netfilter: arptables: Select NETFILTER_FAMILY_ARP when building arp_tables.c
[sfrench/cifs-2.6.git] / net / ipv4 / tcp.c
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * INET         An implementation of the TCP/IP protocol suite for the LINUX
4  *              operating system.  INET is implemented using the  BSD Socket
5  *              interface as the means of communication with the user level.
6  *
7  *              Implementation of the Transmission Control Protocol(TCP).
8  *
9  * Authors:     Ross Biro
10  *              Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
11  *              Mark Evans, <evansmp@uhura.aston.ac.uk>
12  *              Corey Minyard <wf-rch!minyard@relay.EU.net>
13  *              Florian La Roche, <flla@stud.uni-sb.de>
14  *              Charles Hedrick, <hedrick@klinzhai.rutgers.edu>
15  *              Linus Torvalds, <torvalds@cs.helsinki.fi>
16  *              Alan Cox, <gw4pts@gw4pts.ampr.org>
17  *              Matthew Dillon, <dillon@apollo.west.oic.com>
18  *              Arnt Gulbrandsen, <agulbra@nvg.unit.no>
19  *              Jorge Cwik, <jorge@laser.satlink.net>
20  *
21  * Fixes:
22  *              Alan Cox        :       Numerous verify_area() calls
23  *              Alan Cox        :       Set the ACK bit on a reset
24  *              Alan Cox        :       Stopped it crashing if it closed while
25  *                                      sk->inuse=1 and was trying to connect
26  *                                      (tcp_err()).
27  *              Alan Cox        :       All icmp error handling was broken
28  *                                      pointers passed where wrong and the
29  *                                      socket was looked up backwards. Nobody
30  *                                      tested any icmp error code obviously.
31  *              Alan Cox        :       tcp_err() now handled properly. It
32  *                                      wakes people on errors. poll
33  *                                      behaves and the icmp error race
34  *                                      has gone by moving it into sock.c
35  *              Alan Cox        :       tcp_send_reset() fixed to work for
36  *                                      everything not just packets for
37  *                                      unknown sockets.
38  *              Alan Cox        :       tcp option processing.
39  *              Alan Cox        :       Reset tweaked (still not 100%) [Had
40  *                                      syn rule wrong]
41  *              Herp Rosmanith  :       More reset fixes
42  *              Alan Cox        :       No longer acks invalid rst frames.
43  *                                      Acking any kind of RST is right out.
44  *              Alan Cox        :       Sets an ignore me flag on an rst
45  *                                      receive otherwise odd bits of prattle
46  *                                      escape still
47  *              Alan Cox        :       Fixed another acking RST frame bug.
48  *                                      Should stop LAN workplace lockups.
49  *              Alan Cox        :       Some tidyups using the new skb list
50  *                                      facilities
51  *              Alan Cox        :       sk->keepopen now seems to work
52  *              Alan Cox        :       Pulls options out correctly on accepts
53  *              Alan Cox        :       Fixed assorted sk->rqueue->next errors
54  *              Alan Cox        :       PSH doesn't end a TCP read. Switched a
55  *                                      bit to skb ops.
56  *              Alan Cox        :       Tidied tcp_data to avoid a potential
57  *                                      nasty.
58  *              Alan Cox        :       Added some better commenting, as the
59  *                                      tcp is hard to follow
60  *              Alan Cox        :       Removed incorrect check for 20 * psh
61  *      Michael O'Reilly        :       ack < copied bug fix.
62  *      Johannes Stille         :       Misc tcp fixes (not all in yet).
63  *              Alan Cox        :       FIN with no memory -> CRASH
64  *              Alan Cox        :       Added socket option proto entries.
65  *                                      Also added awareness of them to accept.
66  *              Alan Cox        :       Added TCP options (SOL_TCP)
67  *              Alan Cox        :       Switched wakeup calls to callbacks,
68  *                                      so the kernel can layer network
69  *                                      sockets.
70  *              Alan Cox        :       Use ip_tos/ip_ttl settings.
71  *              Alan Cox        :       Handle FIN (more) properly (we hope).
72  *              Alan Cox        :       RST frames sent on unsynchronised
73  *                                      state ack error.
74  *              Alan Cox        :       Put in missing check for SYN bit.
75  *              Alan Cox        :       Added tcp_select_window() aka NET2E
76  *                                      window non shrink trick.
77  *              Alan Cox        :       Added a couple of small NET2E timer
78  *                                      fixes
79  *              Charles Hedrick :       TCP fixes
80  *              Toomas Tamm     :       TCP window fixes
81  *              Alan Cox        :       Small URG fix to rlogin ^C ack fight
82  *              Charles Hedrick :       Rewrote most of it to actually work
83  *              Linus           :       Rewrote tcp_read() and URG handling
84  *                                      completely
85  *              Gerhard Koerting:       Fixed some missing timer handling
86  *              Matthew Dillon  :       Reworked TCP machine states as per RFC
87  *              Gerhard Koerting:       PC/TCP workarounds
88  *              Adam Caldwell   :       Assorted timer/timing errors
89  *              Matthew Dillon  :       Fixed another RST bug
90  *              Alan Cox        :       Move to kernel side addressing changes.
91  *              Alan Cox        :       Beginning work on TCP fastpathing
92  *                                      (not yet usable)
93  *              Arnt Gulbrandsen:       Turbocharged tcp_check() routine.
94  *              Alan Cox        :       TCP fast path debugging
95  *              Alan Cox        :       Window clamping
96  *              Michael Riepe   :       Bug in tcp_check()
97  *              Matt Dillon     :       More TCP improvements and RST bug fixes
98  *              Matt Dillon     :       Yet more small nasties remove from the
99  *                                      TCP code (Be very nice to this man if
100  *                                      tcp finally works 100%) 8)
101  *              Alan Cox        :       BSD accept semantics.
102  *              Alan Cox        :       Reset on closedown bug.
103  *      Peter De Schrijver      :       ENOTCONN check missing in tcp_sendto().
104  *              Michael Pall    :       Handle poll() after URG properly in
105  *                                      all cases.
106  *              Michael Pall    :       Undo the last fix in tcp_read_urg()
107  *                                      (multi URG PUSH broke rlogin).
108  *              Michael Pall    :       Fix the multi URG PUSH problem in
109  *                                      tcp_readable(), poll() after URG
110  *                                      works now.
111  *              Michael Pall    :       recv(...,MSG_OOB) never blocks in the
112  *                                      BSD api.
113  *              Alan Cox        :       Changed the semantics of sk->socket to
114  *                                      fix a race and a signal problem with
115  *                                      accept() and async I/O.
116  *              Alan Cox        :       Relaxed the rules on tcp_sendto().
117  *              Yury Shevchuk   :       Really fixed accept() blocking problem.
118  *              Craig I. Hagan  :       Allow for BSD compatible TIME_WAIT for
119  *                                      clients/servers which listen in on
120  *                                      fixed ports.
121  *              Alan Cox        :       Cleaned the above up and shrank it to
122  *                                      a sensible code size.
123  *              Alan Cox        :       Self connect lockup fix.
124  *              Alan Cox        :       No connect to multicast.
125  *              Ross Biro       :       Close unaccepted children on master
126  *                                      socket close.
127  *              Alan Cox        :       Reset tracing code.
128  *              Alan Cox        :       Spurious resets on shutdown.
129  *              Alan Cox        :       Giant 15 minute/60 second timer error
130  *              Alan Cox        :       Small whoops in polling before an
131  *                                      accept.
132  *              Alan Cox        :       Kept the state trace facility since
133  *                                      it's handy for debugging.
134  *              Alan Cox        :       More reset handler fixes.
135  *              Alan Cox        :       Started rewriting the code based on
136  *                                      the RFC's for other useful protocol
137  *                                      references see: Comer, KA9Q NOS, and
138  *                                      for a reference on the difference
139  *                                      between specifications and how BSD
140  *                                      works see the 4.4lite source.
141  *              A.N.Kuznetsov   :       Don't time wait on completion of tidy
142  *                                      close.
143  *              Linus Torvalds  :       Fin/Shutdown & copied_seq changes.
144  *              Linus Torvalds  :       Fixed BSD port reuse to work first syn
145  *              Alan Cox        :       Reimplemented timers as per the RFC
146  *                                      and using multiple timers for sanity.
147  *              Alan Cox        :       Small bug fixes, and a lot of new
148  *                                      comments.
149  *              Alan Cox        :       Fixed dual reader crash by locking
150  *                                      the buffers (much like datagram.c)
151  *              Alan Cox        :       Fixed stuck sockets in probe. A probe
152  *                                      now gets fed up of retrying without
153  *                                      (even a no space) answer.
154  *              Alan Cox        :       Extracted closing code better
155  *              Alan Cox        :       Fixed the closing state machine to
156  *                                      resemble the RFC.
157  *              Alan Cox        :       More 'per spec' fixes.
158  *              Jorge Cwik      :       Even faster checksumming.
159  *              Alan Cox        :       tcp_data() doesn't ack illegal PSH
160  *                                      only frames. At least one pc tcp stack
161  *                                      generates them.
162  *              Alan Cox        :       Cache last socket.
163  *              Alan Cox        :       Per route irtt.
164  *              Matt Day        :       poll()->select() match BSD precisely on error
165  *              Alan Cox        :       New buffers
166  *              Marc Tamsky     :       Various sk->prot->retransmits and
167  *                                      sk->retransmits misupdating fixed.
168  *                                      Fixed tcp_write_timeout: stuck close,
169  *                                      and TCP syn retries gets used now.
170  *              Mark Yarvis     :       In tcp_read_wakeup(), don't send an
171  *                                      ack if state is TCP_CLOSED.
172  *              Alan Cox        :       Look up device on a retransmit - routes may
173  *                                      change. Doesn't yet cope with MSS shrink right
174  *                                      but it's a start!
175  *              Marc Tamsky     :       Closing in closing fixes.
176  *              Mike Shaver     :       RFC1122 verifications.
177  *              Alan Cox        :       rcv_saddr errors.
178  *              Alan Cox        :       Block double connect().
179  *              Alan Cox        :       Small hooks for enSKIP.
180  *              Alexey Kuznetsov:       Path MTU discovery.
181  *              Alan Cox        :       Support soft errors.
182  *              Alan Cox        :       Fix MTU discovery pathological case
183  *                                      when the remote claims no mtu!
184  *              Marc Tamsky     :       TCP_CLOSE fix.
185  *              Colin (G3TNE)   :       Send a reset on syn ack replies in
186  *                                      window but wrong (fixes NT lpd problems)
187  *              Pedro Roque     :       Better TCP window handling, delayed ack.
188  *              Joerg Reuter    :       No modification of locked buffers in
189  *                                      tcp_do_retransmit()
190  *              Eric Schenk     :       Changed receiver side silly window
191  *                                      avoidance algorithm to BSD style
192  *                                      algorithm. This doubles throughput
193  *                                      against machines running Solaris,
194  *                                      and seems to result in general
195  *                                      improvement.
196  *      Stefan Magdalinski      :       adjusted tcp_readable() to fix FIONREAD
197  *      Willy Konynenberg       :       Transparent proxying support.
198  *      Mike McLagan            :       Routing by source
199  *              Keith Owens     :       Do proper merging with partial SKB's in
200  *                                      tcp_do_sendmsg to avoid burstiness.
201  *              Eric Schenk     :       Fix fast close down bug with
202  *                                      shutdown() followed by close().
203  *              Andi Kleen      :       Make poll agree with SIGIO
204  *      Salvatore Sanfilippo    :       Support SO_LINGER with linger == 1 and
205  *                                      lingertime == 0 (RFC 793 ABORT Call)
206  *      Hirokazu Takahashi      :       Use copy_from_user() instead of
207  *                                      csum_and_copy_from_user() if possible.
208  *
209  * Description of States:
210  *
211  *      TCP_SYN_SENT            sent a connection request, waiting for ack
212  *
213  *      TCP_SYN_RECV            received a connection request, sent ack,
214  *                              waiting for final ack in three-way handshake.
215  *
216  *      TCP_ESTABLISHED         connection established
217  *
218  *      TCP_FIN_WAIT1           our side has shutdown, waiting to complete
219  *                              transmission of remaining buffered data
220  *
221  *      TCP_FIN_WAIT2           all buffered data sent, waiting for remote
222  *                              to shutdown
223  *
224  *      TCP_CLOSING             both sides have shutdown but we still have
225  *                              data we have to finish sending
226  *
227  *      TCP_TIME_WAIT           timeout to catch resent junk before entering
228  *                              closed, can only be entered from FIN_WAIT2
229  *                              or CLOSING.  Required because the other end
230  *                              may not have gotten our last ACK causing it
231  *                              to retransmit the data packet (which we ignore)
232  *
233  *      TCP_CLOSE_WAIT          remote side has shutdown and is waiting for
234  *                              us to finish writing our data and to shutdown
235  *                              (we have to close() to move on to LAST_ACK)
236  *
237  *      TCP_LAST_ACK            out side has shutdown after remote has
238  *                              shutdown.  There may still be data in our
239  *                              buffer that we have to finish sending
240  *
241  *      TCP_CLOSE               socket is finished
242  */
243
244 #define pr_fmt(fmt) "TCP: " fmt
245
246 #include <crypto/hash.h>
247 #include <linux/kernel.h>
248 #include <linux/module.h>
249 #include <linux/types.h>
250 #include <linux/fcntl.h>
251 #include <linux/poll.h>
252 #include <linux/inet_diag.h>
253 #include <linux/init.h>
254 #include <linux/fs.h>
255 #include <linux/skbuff.h>
256 #include <linux/scatterlist.h>
257 #include <linux/splice.h>
258 #include <linux/net.h>
259 #include <linux/socket.h>
260 #include <linux/random.h>
261 #include <linux/memblock.h>
262 #include <linux/highmem.h>
263 #include <linux/cache.h>
264 #include <linux/err.h>
265 #include <linux/time.h>
266 #include <linux/slab.h>
267 #include <linux/errqueue.h>
268 #include <linux/static_key.h>
269 #include <linux/btf.h>
270
271 #include <net/icmp.h>
272 #include <net/inet_common.h>
273 #include <net/tcp.h>
274 #include <net/mptcp.h>
275 #include <net/xfrm.h>
276 #include <net/ip.h>
277 #include <net/sock.h>
278
279 #include <linux/uaccess.h>
280 #include <asm/ioctls.h>
281 #include <net/busy_poll.h>
282 #include <net/rps.h>
283
284 /* Track pending CMSGs. */
285 enum {
286         TCP_CMSG_INQ = 1,
287         TCP_CMSG_TS = 2
288 };
289
290 DEFINE_PER_CPU(unsigned int, tcp_orphan_count);
291 EXPORT_PER_CPU_SYMBOL_GPL(tcp_orphan_count);
292
293 long sysctl_tcp_mem[3] __read_mostly;
294 EXPORT_SYMBOL(sysctl_tcp_mem);
295
296 atomic_long_t tcp_memory_allocated ____cacheline_aligned_in_smp;        /* Current allocated memory. */
297 EXPORT_SYMBOL(tcp_memory_allocated);
298 DEFINE_PER_CPU(int, tcp_memory_per_cpu_fw_alloc);
299 EXPORT_PER_CPU_SYMBOL_GPL(tcp_memory_per_cpu_fw_alloc);
300
301 #if IS_ENABLED(CONFIG_SMC)
302 DEFINE_STATIC_KEY_FALSE(tcp_have_smc);
303 EXPORT_SYMBOL(tcp_have_smc);
304 #endif
305
306 /*
307  * Current number of TCP sockets.
308  */
309 struct percpu_counter tcp_sockets_allocated ____cacheline_aligned_in_smp;
310 EXPORT_SYMBOL(tcp_sockets_allocated);
311
312 /*
313  * TCP splice context
314  */
315 struct tcp_splice_state {
316         struct pipe_inode_info *pipe;
317         size_t len;
318         unsigned int flags;
319 };
320
321 /*
322  * Pressure flag: try to collapse.
323  * Technical note: it is used by multiple contexts non atomically.
324  * All the __sk_mem_schedule() is of this nature: accounting
325  * is strict, actions are advisory and have some latency.
326  */
327 unsigned long tcp_memory_pressure __read_mostly;
328 EXPORT_SYMBOL_GPL(tcp_memory_pressure);
329
330 void tcp_enter_memory_pressure(struct sock *sk)
331 {
332         unsigned long val;
333
334         if (READ_ONCE(tcp_memory_pressure))
335                 return;
336         val = jiffies;
337
338         if (!val)
339                 val--;
340         if (!cmpxchg(&tcp_memory_pressure, 0, val))
341                 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMEMORYPRESSURES);
342 }
343 EXPORT_SYMBOL_GPL(tcp_enter_memory_pressure);
344
345 void tcp_leave_memory_pressure(struct sock *sk)
346 {
347         unsigned long val;
348
349         if (!READ_ONCE(tcp_memory_pressure))
350                 return;
351         val = xchg(&tcp_memory_pressure, 0);
352         if (val)
353                 NET_ADD_STATS(sock_net(sk), LINUX_MIB_TCPMEMORYPRESSURESCHRONO,
354                               jiffies_to_msecs(jiffies - val));
355 }
356 EXPORT_SYMBOL_GPL(tcp_leave_memory_pressure);
357
358 /* Convert seconds to retransmits based on initial and max timeout */
359 static u8 secs_to_retrans(int seconds, int timeout, int rto_max)
360 {
361         u8 res = 0;
362
363         if (seconds > 0) {
364                 int period = timeout;
365
366                 res = 1;
367                 while (seconds > period && res < 255) {
368                         res++;
369                         timeout <<= 1;
370                         if (timeout > rto_max)
371                                 timeout = rto_max;
372                         period += timeout;
373                 }
374         }
375         return res;
376 }
377
378 /* Convert retransmits to seconds based on initial and max timeout */
379 static int retrans_to_secs(u8 retrans, int timeout, int rto_max)
380 {
381         int period = 0;
382
383         if (retrans > 0) {
384                 period = timeout;
385                 while (--retrans) {
386                         timeout <<= 1;
387                         if (timeout > rto_max)
388                                 timeout = rto_max;
389                         period += timeout;
390                 }
391         }
392         return period;
393 }
394
395 static u64 tcp_compute_delivery_rate(const struct tcp_sock *tp)
396 {
397         u32 rate = READ_ONCE(tp->rate_delivered);
398         u32 intv = READ_ONCE(tp->rate_interval_us);
399         u64 rate64 = 0;
400
401         if (rate && intv) {
402                 rate64 = (u64)rate * tp->mss_cache * USEC_PER_SEC;
403                 do_div(rate64, intv);
404         }
405         return rate64;
406 }
407
408 /* Address-family independent initialization for a tcp_sock.
409  *
410  * NOTE: A lot of things set to zero explicitly by call to
411  *       sk_alloc() so need not be done here.
412  */
413 void tcp_init_sock(struct sock *sk)
414 {
415         struct inet_connection_sock *icsk = inet_csk(sk);
416         struct tcp_sock *tp = tcp_sk(sk);
417
418         tp->out_of_order_queue = RB_ROOT;
419         sk->tcp_rtx_queue = RB_ROOT;
420         tcp_init_xmit_timers(sk);
421         INIT_LIST_HEAD(&tp->tsq_node);
422         INIT_LIST_HEAD(&tp->tsorted_sent_queue);
423
424         icsk->icsk_rto = TCP_TIMEOUT_INIT;
425         icsk->icsk_rto_min = TCP_RTO_MIN;
426         icsk->icsk_delack_max = TCP_DELACK_MAX;
427         tp->mdev_us = jiffies_to_usecs(TCP_TIMEOUT_INIT);
428         minmax_reset(&tp->rtt_min, tcp_jiffies32, ~0U);
429
430         /* So many TCP implementations out there (incorrectly) count the
431          * initial SYN frame in their delayed-ACK and congestion control
432          * algorithms that we must have the following bandaid to talk
433          * efficiently to them.  -DaveM
434          */
435         tcp_snd_cwnd_set(tp, TCP_INIT_CWND);
436
437         /* There's a bubble in the pipe until at least the first ACK. */
438         tp->app_limited = ~0U;
439         tp->rate_app_limited = 1;
440
441         /* See draft-stevens-tcpca-spec-01 for discussion of the
442          * initialization of these values.
443          */
444         tp->snd_ssthresh = TCP_INFINITE_SSTHRESH;
445         tp->snd_cwnd_clamp = ~0;
446         tp->mss_cache = TCP_MSS_DEFAULT;
447
448         tp->reordering = READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_reordering);
449         tcp_assign_congestion_control(sk);
450
451         tp->tsoffset = 0;
452         tp->rack.reo_wnd_steps = 1;
453
454         sk->sk_write_space = sk_stream_write_space;
455         sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
456
457         icsk->icsk_sync_mss = tcp_sync_mss;
458
459         WRITE_ONCE(sk->sk_sndbuf, READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_wmem[1]));
460         WRITE_ONCE(sk->sk_rcvbuf, READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_rmem[1]));
461         tcp_scaling_ratio_init(sk);
462
463         set_bit(SOCK_SUPPORT_ZC, &sk->sk_socket->flags);
464         sk_sockets_allocated_inc(sk);
465 }
466 EXPORT_SYMBOL(tcp_init_sock);
467
468 static void tcp_tx_timestamp(struct sock *sk, u16 tsflags)
469 {
470         struct sk_buff *skb = tcp_write_queue_tail(sk);
471
472         if (tsflags && skb) {
473                 struct skb_shared_info *shinfo = skb_shinfo(skb);
474                 struct tcp_skb_cb *tcb = TCP_SKB_CB(skb);
475
476                 sock_tx_timestamp(sk, tsflags, &shinfo->tx_flags);
477                 if (tsflags & SOF_TIMESTAMPING_TX_ACK)
478                         tcb->txstamp_ack = 1;
479                 if (tsflags & SOF_TIMESTAMPING_TX_RECORD_MASK)
480                         shinfo->tskey = TCP_SKB_CB(skb)->seq + skb->len - 1;
481         }
482 }
483
484 static bool tcp_stream_is_readable(struct sock *sk, int target)
485 {
486         if (tcp_epollin_ready(sk, target))
487                 return true;
488         return sk_is_readable(sk);
489 }
490
491 /*
492  *      Wait for a TCP event.
493  *
494  *      Note that we don't need to lock the socket, as the upper poll layers
495  *      take care of normal races (between the test and the event) and we don't
496  *      go look at any of the socket buffers directly.
497  */
498 __poll_t tcp_poll(struct file *file, struct socket *sock, poll_table *wait)
499 {
500         __poll_t mask;
501         struct sock *sk = sock->sk;
502         const struct tcp_sock *tp = tcp_sk(sk);
503         u8 shutdown;
504         int state;
505
506         sock_poll_wait(file, sock, wait);
507
508         state = inet_sk_state_load(sk);
509         if (state == TCP_LISTEN)
510                 return inet_csk_listen_poll(sk);
511
512         /* Socket is not locked. We are protected from async events
513          * by poll logic and correct handling of state changes
514          * made by other threads is impossible in any case.
515          */
516
517         mask = 0;
518
519         /*
520          * EPOLLHUP is certainly not done right. But poll() doesn't
521          * have a notion of HUP in just one direction, and for a
522          * socket the read side is more interesting.
523          *
524          * Some poll() documentation says that EPOLLHUP is incompatible
525          * with the EPOLLOUT/POLLWR flags, so somebody should check this
526          * all. But careful, it tends to be safer to return too many
527          * bits than too few, and you can easily break real applications
528          * if you don't tell them that something has hung up!
529          *
530          * Check-me.
531          *
532          * Check number 1. EPOLLHUP is _UNMASKABLE_ event (see UNIX98 and
533          * our fs/select.c). It means that after we received EOF,
534          * poll always returns immediately, making impossible poll() on write()
535          * in state CLOSE_WAIT. One solution is evident --- to set EPOLLHUP
536          * if and only if shutdown has been made in both directions.
537          * Actually, it is interesting to look how Solaris and DUX
538          * solve this dilemma. I would prefer, if EPOLLHUP were maskable,
539          * then we could set it on SND_SHUTDOWN. BTW examples given
540          * in Stevens' books assume exactly this behaviour, it explains
541          * why EPOLLHUP is incompatible with EPOLLOUT.  --ANK
542          *
543          * NOTE. Check for TCP_CLOSE is added. The goal is to prevent
544          * blocking on fresh not-connected or disconnected socket. --ANK
545          */
546         shutdown = READ_ONCE(sk->sk_shutdown);
547         if (shutdown == SHUTDOWN_MASK || state == TCP_CLOSE)
548                 mask |= EPOLLHUP;
549         if (shutdown & RCV_SHUTDOWN)
550                 mask |= EPOLLIN | EPOLLRDNORM | EPOLLRDHUP;
551
552         /* Connected or passive Fast Open socket? */
553         if (state != TCP_SYN_SENT &&
554             (state != TCP_SYN_RECV || rcu_access_pointer(tp->fastopen_rsk))) {
555                 int target = sock_rcvlowat(sk, 0, INT_MAX);
556                 u16 urg_data = READ_ONCE(tp->urg_data);
557
558                 if (unlikely(urg_data) &&
559                     READ_ONCE(tp->urg_seq) == READ_ONCE(tp->copied_seq) &&
560                     !sock_flag(sk, SOCK_URGINLINE))
561                         target++;
562
563                 if (tcp_stream_is_readable(sk, target))
564                         mask |= EPOLLIN | EPOLLRDNORM;
565
566                 if (!(shutdown & SEND_SHUTDOWN)) {
567                         if (__sk_stream_is_writeable(sk, 1)) {
568                                 mask |= EPOLLOUT | EPOLLWRNORM;
569                         } else {  /* send SIGIO later */
570                                 sk_set_bit(SOCKWQ_ASYNC_NOSPACE, sk);
571                                 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
572
573                                 /* Race breaker. If space is freed after
574                                  * wspace test but before the flags are set,
575                                  * IO signal will be lost. Memory barrier
576                                  * pairs with the input side.
577                                  */
578                                 smp_mb__after_atomic();
579                                 if (__sk_stream_is_writeable(sk, 1))
580                                         mask |= EPOLLOUT | EPOLLWRNORM;
581                         }
582                 } else
583                         mask |= EPOLLOUT | EPOLLWRNORM;
584
585                 if (urg_data & TCP_URG_VALID)
586                         mask |= EPOLLPRI;
587         } else if (state == TCP_SYN_SENT &&
588                    inet_test_bit(DEFER_CONNECT, sk)) {
589                 /* Active TCP fastopen socket with defer_connect
590                  * Return EPOLLOUT so application can call write()
591                  * in order for kernel to generate SYN+data
592                  */
593                 mask |= EPOLLOUT | EPOLLWRNORM;
594         }
595         /* This barrier is coupled with smp_wmb() in tcp_reset() */
596         smp_rmb();
597         if (READ_ONCE(sk->sk_err) ||
598             !skb_queue_empty_lockless(&sk->sk_error_queue))
599                 mask |= EPOLLERR;
600
601         return mask;
602 }
603 EXPORT_SYMBOL(tcp_poll);
604
605 int tcp_ioctl(struct sock *sk, int cmd, int *karg)
606 {
607         struct tcp_sock *tp = tcp_sk(sk);
608         int answ;
609         bool slow;
610
611         switch (cmd) {
612         case SIOCINQ:
613                 if (sk->sk_state == TCP_LISTEN)
614                         return -EINVAL;
615
616                 slow = lock_sock_fast(sk);
617                 answ = tcp_inq(sk);
618                 unlock_sock_fast(sk, slow);
619                 break;
620         case SIOCATMARK:
621                 answ = READ_ONCE(tp->urg_data) &&
622                        READ_ONCE(tp->urg_seq) == READ_ONCE(tp->copied_seq);
623                 break;
624         case SIOCOUTQ:
625                 if (sk->sk_state == TCP_LISTEN)
626                         return -EINVAL;
627
628                 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
629                         answ = 0;
630                 else
631                         answ = READ_ONCE(tp->write_seq) - tp->snd_una;
632                 break;
633         case SIOCOUTQNSD:
634                 if (sk->sk_state == TCP_LISTEN)
635                         return -EINVAL;
636
637                 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
638                         answ = 0;
639                 else
640                         answ = READ_ONCE(tp->write_seq) -
641                                READ_ONCE(tp->snd_nxt);
642                 break;
643         default:
644                 return -ENOIOCTLCMD;
645         }
646
647         *karg = answ;
648         return 0;
649 }
650 EXPORT_SYMBOL(tcp_ioctl);
651
652 void tcp_mark_push(struct tcp_sock *tp, struct sk_buff *skb)
653 {
654         TCP_SKB_CB(skb)->tcp_flags |= TCPHDR_PSH;
655         tp->pushed_seq = tp->write_seq;
656 }
657
658 static inline bool forced_push(const struct tcp_sock *tp)
659 {
660         return after(tp->write_seq, tp->pushed_seq + (tp->max_window >> 1));
661 }
662
663 void tcp_skb_entail(struct sock *sk, struct sk_buff *skb)
664 {
665         struct tcp_sock *tp = tcp_sk(sk);
666         struct tcp_skb_cb *tcb = TCP_SKB_CB(skb);
667
668         tcb->seq     = tcb->end_seq = tp->write_seq;
669         tcb->tcp_flags = TCPHDR_ACK;
670         __skb_header_release(skb);
671         tcp_add_write_queue_tail(sk, skb);
672         sk_wmem_queued_add(sk, skb->truesize);
673         sk_mem_charge(sk, skb->truesize);
674         if (tp->nonagle & TCP_NAGLE_PUSH)
675                 tp->nonagle &= ~TCP_NAGLE_PUSH;
676
677         tcp_slow_start_after_idle_check(sk);
678 }
679
680 static inline void tcp_mark_urg(struct tcp_sock *tp, int flags)
681 {
682         if (flags & MSG_OOB)
683                 tp->snd_up = tp->write_seq;
684 }
685
686 /* If a not yet filled skb is pushed, do not send it if
687  * we have data packets in Qdisc or NIC queues :
688  * Because TX completion will happen shortly, it gives a chance
689  * to coalesce future sendmsg() payload into this skb, without
690  * need for a timer, and with no latency trade off.
691  * As packets containing data payload have a bigger truesize
692  * than pure acks (dataless) packets, the last checks prevent
693  * autocorking if we only have an ACK in Qdisc/NIC queues,
694  * or if TX completion was delayed after we processed ACK packet.
695  */
696 static bool tcp_should_autocork(struct sock *sk, struct sk_buff *skb,
697                                 int size_goal)
698 {
699         return skb->len < size_goal &&
700                READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_autocorking) &&
701                !tcp_rtx_queue_empty(sk) &&
702                refcount_read(&sk->sk_wmem_alloc) > skb->truesize &&
703                tcp_skb_can_collapse_to(skb);
704 }
705
706 void tcp_push(struct sock *sk, int flags, int mss_now,
707               int nonagle, int size_goal)
708 {
709         struct tcp_sock *tp = tcp_sk(sk);
710         struct sk_buff *skb;
711
712         skb = tcp_write_queue_tail(sk);
713         if (!skb)
714                 return;
715         if (!(flags & MSG_MORE) || forced_push(tp))
716                 tcp_mark_push(tp, skb);
717
718         tcp_mark_urg(tp, flags);
719
720         if (tcp_should_autocork(sk, skb, size_goal)) {
721
722                 /* avoid atomic op if TSQ_THROTTLED bit is already set */
723                 if (!test_bit(TSQ_THROTTLED, &sk->sk_tsq_flags)) {
724                         NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPAUTOCORKING);
725                         set_bit(TSQ_THROTTLED, &sk->sk_tsq_flags);
726                         smp_mb__after_atomic();
727                 }
728                 /* It is possible TX completion already happened
729                  * before we set TSQ_THROTTLED.
730                  */
731                 if (refcount_read(&sk->sk_wmem_alloc) > skb->truesize)
732                         return;
733         }
734
735         if (flags & MSG_MORE)
736                 nonagle = TCP_NAGLE_CORK;
737
738         __tcp_push_pending_frames(sk, mss_now, nonagle);
739 }
740
741 static int tcp_splice_data_recv(read_descriptor_t *rd_desc, struct sk_buff *skb,
742                                 unsigned int offset, size_t len)
743 {
744         struct tcp_splice_state *tss = rd_desc->arg.data;
745         int ret;
746
747         ret = skb_splice_bits(skb, skb->sk, offset, tss->pipe,
748                               min(rd_desc->count, len), tss->flags);
749         if (ret > 0)
750                 rd_desc->count -= ret;
751         return ret;
752 }
753
754 static int __tcp_splice_read(struct sock *sk, struct tcp_splice_state *tss)
755 {
756         /* Store TCP splice context information in read_descriptor_t. */
757         read_descriptor_t rd_desc = {
758                 .arg.data = tss,
759                 .count    = tss->len,
760         };
761
762         return tcp_read_sock(sk, &rd_desc, tcp_splice_data_recv);
763 }
764
765 /**
766  *  tcp_splice_read - splice data from TCP socket to a pipe
767  * @sock:       socket to splice from
768  * @ppos:       position (not valid)
769  * @pipe:       pipe to splice to
770  * @len:        number of bytes to splice
771  * @flags:      splice modifier flags
772  *
773  * Description:
774  *    Will read pages from given socket and fill them into a pipe.
775  *
776  **/
777 ssize_t tcp_splice_read(struct socket *sock, loff_t *ppos,
778                         struct pipe_inode_info *pipe, size_t len,
779                         unsigned int flags)
780 {
781         struct sock *sk = sock->sk;
782         struct tcp_splice_state tss = {
783                 .pipe = pipe,
784                 .len = len,
785                 .flags = flags,
786         };
787         long timeo;
788         ssize_t spliced;
789         int ret;
790
791         sock_rps_record_flow(sk);
792         /*
793          * We can't seek on a socket input
794          */
795         if (unlikely(*ppos))
796                 return -ESPIPE;
797
798         ret = spliced = 0;
799
800         lock_sock(sk);
801
802         timeo = sock_rcvtimeo(sk, sock->file->f_flags & O_NONBLOCK);
803         while (tss.len) {
804                 ret = __tcp_splice_read(sk, &tss);
805                 if (ret < 0)
806                         break;
807                 else if (!ret) {
808                         if (spliced)
809                                 break;
810                         if (sock_flag(sk, SOCK_DONE))
811                                 break;
812                         if (sk->sk_err) {
813                                 ret = sock_error(sk);
814                                 break;
815                         }
816                         if (sk->sk_shutdown & RCV_SHUTDOWN)
817                                 break;
818                         if (sk->sk_state == TCP_CLOSE) {
819                                 /*
820                                  * This occurs when user tries to read
821                                  * from never connected socket.
822                                  */
823                                 ret = -ENOTCONN;
824                                 break;
825                         }
826                         if (!timeo) {
827                                 ret = -EAGAIN;
828                                 break;
829                         }
830                         /* if __tcp_splice_read() got nothing while we have
831                          * an skb in receive queue, we do not want to loop.
832                          * This might happen with URG data.
833                          */
834                         if (!skb_queue_empty(&sk->sk_receive_queue))
835                                 break;
836                         ret = sk_wait_data(sk, &timeo, NULL);
837                         if (ret < 0)
838                                 break;
839                         if (signal_pending(current)) {
840                                 ret = sock_intr_errno(timeo);
841                                 break;
842                         }
843                         continue;
844                 }
845                 tss.len -= ret;
846                 spliced += ret;
847
848                 if (!tss.len || !timeo)
849                         break;
850                 release_sock(sk);
851                 lock_sock(sk);
852
853                 if (sk->sk_err || sk->sk_state == TCP_CLOSE ||
854                     (sk->sk_shutdown & RCV_SHUTDOWN) ||
855                     signal_pending(current))
856                         break;
857         }
858
859         release_sock(sk);
860
861         if (spliced)
862                 return spliced;
863
864         return ret;
865 }
866 EXPORT_SYMBOL(tcp_splice_read);
867
868 struct sk_buff *tcp_stream_alloc_skb(struct sock *sk, gfp_t gfp,
869                                      bool force_schedule)
870 {
871         struct sk_buff *skb;
872
873         skb = alloc_skb_fclone(MAX_TCP_HEADER, gfp);
874         if (likely(skb)) {
875                 bool mem_scheduled;
876
877                 skb->truesize = SKB_TRUESIZE(skb_end_offset(skb));
878                 if (force_schedule) {
879                         mem_scheduled = true;
880                         sk_forced_mem_schedule(sk, skb->truesize);
881                 } else {
882                         mem_scheduled = sk_wmem_schedule(sk, skb->truesize);
883                 }
884                 if (likely(mem_scheduled)) {
885                         skb_reserve(skb, MAX_TCP_HEADER);
886                         skb->ip_summed = CHECKSUM_PARTIAL;
887                         INIT_LIST_HEAD(&skb->tcp_tsorted_anchor);
888                         return skb;
889                 }
890                 __kfree_skb(skb);
891         } else {
892                 sk->sk_prot->enter_memory_pressure(sk);
893                 sk_stream_moderate_sndbuf(sk);
894         }
895         return NULL;
896 }
897
898 static unsigned int tcp_xmit_size_goal(struct sock *sk, u32 mss_now,
899                                        int large_allowed)
900 {
901         struct tcp_sock *tp = tcp_sk(sk);
902         u32 new_size_goal, size_goal;
903
904         if (!large_allowed)
905                 return mss_now;
906
907         /* Note : tcp_tso_autosize() will eventually split this later */
908         new_size_goal = tcp_bound_to_half_wnd(tp, sk->sk_gso_max_size);
909
910         /* We try hard to avoid divides here */
911         size_goal = tp->gso_segs * mss_now;
912         if (unlikely(new_size_goal < size_goal ||
913                      new_size_goal >= size_goal + mss_now)) {
914                 tp->gso_segs = min_t(u16, new_size_goal / mss_now,
915                                      sk->sk_gso_max_segs);
916                 size_goal = tp->gso_segs * mss_now;
917         }
918
919         return max(size_goal, mss_now);
920 }
921
922 int tcp_send_mss(struct sock *sk, int *size_goal, int flags)
923 {
924         int mss_now;
925
926         mss_now = tcp_current_mss(sk);
927         *size_goal = tcp_xmit_size_goal(sk, mss_now, !(flags & MSG_OOB));
928
929         return mss_now;
930 }
931
932 /* In some cases, sendmsg() could have added an skb to the write queue,
933  * but failed adding payload on it. We need to remove it to consume less
934  * memory, but more importantly be able to generate EPOLLOUT for Edge Trigger
935  * epoll() users. Another reason is that tcp_write_xmit() does not like
936  * finding an empty skb in the write queue.
937  */
938 void tcp_remove_empty_skb(struct sock *sk)
939 {
940         struct sk_buff *skb = tcp_write_queue_tail(sk);
941
942         if (skb && TCP_SKB_CB(skb)->seq == TCP_SKB_CB(skb)->end_seq) {
943                 tcp_unlink_write_queue(skb, sk);
944                 if (tcp_write_queue_empty(sk))
945                         tcp_chrono_stop(sk, TCP_CHRONO_BUSY);
946                 tcp_wmem_free_skb(sk, skb);
947         }
948 }
949
950 /* skb changing from pure zc to mixed, must charge zc */
951 static int tcp_downgrade_zcopy_pure(struct sock *sk, struct sk_buff *skb)
952 {
953         if (unlikely(skb_zcopy_pure(skb))) {
954                 u32 extra = skb->truesize -
955                             SKB_TRUESIZE(skb_end_offset(skb));
956
957                 if (!sk_wmem_schedule(sk, extra))
958                         return -ENOMEM;
959
960                 sk_mem_charge(sk, extra);
961                 skb_shinfo(skb)->flags &= ~SKBFL_PURE_ZEROCOPY;
962         }
963         return 0;
964 }
965
966
967 int tcp_wmem_schedule(struct sock *sk, int copy)
968 {
969         int left;
970
971         if (likely(sk_wmem_schedule(sk, copy)))
972                 return copy;
973
974         /* We could be in trouble if we have nothing queued.
975          * Use whatever is left in sk->sk_forward_alloc and tcp_wmem[0]
976          * to guarantee some progress.
977          */
978         left = READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_wmem[0]) - sk->sk_wmem_queued;
979         if (left > 0)
980                 sk_forced_mem_schedule(sk, min(left, copy));
981         return min(copy, sk->sk_forward_alloc);
982 }
983
984 void tcp_free_fastopen_req(struct tcp_sock *tp)
985 {
986         if (tp->fastopen_req) {
987                 kfree(tp->fastopen_req);
988                 tp->fastopen_req = NULL;
989         }
990 }
991
992 int tcp_sendmsg_fastopen(struct sock *sk, struct msghdr *msg, int *copied,
993                          size_t size, struct ubuf_info *uarg)
994 {
995         struct tcp_sock *tp = tcp_sk(sk);
996         struct inet_sock *inet = inet_sk(sk);
997         struct sockaddr *uaddr = msg->msg_name;
998         int err, flags;
999
1000         if (!(READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_fastopen) &
1001               TFO_CLIENT_ENABLE) ||
1002             (uaddr && msg->msg_namelen >= sizeof(uaddr->sa_family) &&
1003              uaddr->sa_family == AF_UNSPEC))
1004                 return -EOPNOTSUPP;
1005         if (tp->fastopen_req)
1006                 return -EALREADY; /* Another Fast Open is in progress */
1007
1008         tp->fastopen_req = kzalloc(sizeof(struct tcp_fastopen_request),
1009                                    sk->sk_allocation);
1010         if (unlikely(!tp->fastopen_req))
1011                 return -ENOBUFS;
1012         tp->fastopen_req->data = msg;
1013         tp->fastopen_req->size = size;
1014         tp->fastopen_req->uarg = uarg;
1015
1016         if (inet_test_bit(DEFER_CONNECT, sk)) {
1017                 err = tcp_connect(sk);
1018                 /* Same failure procedure as in tcp_v4/6_connect */
1019                 if (err) {
1020                         tcp_set_state(sk, TCP_CLOSE);
1021                         inet->inet_dport = 0;
1022                         sk->sk_route_caps = 0;
1023                 }
1024         }
1025         flags = (msg->msg_flags & MSG_DONTWAIT) ? O_NONBLOCK : 0;
1026         err = __inet_stream_connect(sk->sk_socket, uaddr,
1027                                     msg->msg_namelen, flags, 1);
1028         /* fastopen_req could already be freed in __inet_stream_connect
1029          * if the connection times out or gets rst
1030          */
1031         if (tp->fastopen_req) {
1032                 *copied = tp->fastopen_req->copied;
1033                 tcp_free_fastopen_req(tp);
1034                 inet_clear_bit(DEFER_CONNECT, sk);
1035         }
1036         return err;
1037 }
1038
1039 int tcp_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t size)
1040 {
1041         struct tcp_sock *tp = tcp_sk(sk);
1042         struct ubuf_info *uarg = NULL;
1043         struct sk_buff *skb;
1044         struct sockcm_cookie sockc;
1045         int flags, err, copied = 0;
1046         int mss_now = 0, size_goal, copied_syn = 0;
1047         int process_backlog = 0;
1048         int zc = 0;
1049         long timeo;
1050
1051         flags = msg->msg_flags;
1052
1053         if ((flags & MSG_ZEROCOPY) && size) {
1054                 if (msg->msg_ubuf) {
1055                         uarg = msg->msg_ubuf;
1056                         if (sk->sk_route_caps & NETIF_F_SG)
1057                                 zc = MSG_ZEROCOPY;
1058                 } else if (sock_flag(sk, SOCK_ZEROCOPY)) {
1059                         skb = tcp_write_queue_tail(sk);
1060                         uarg = msg_zerocopy_realloc(sk, size, skb_zcopy(skb));
1061                         if (!uarg) {
1062                                 err = -ENOBUFS;
1063                                 goto out_err;
1064                         }
1065                         if (sk->sk_route_caps & NETIF_F_SG)
1066                                 zc = MSG_ZEROCOPY;
1067                         else
1068                                 uarg_to_msgzc(uarg)->zerocopy = 0;
1069                 }
1070         } else if (unlikely(msg->msg_flags & MSG_SPLICE_PAGES) && size) {
1071                 if (sk->sk_route_caps & NETIF_F_SG)
1072                         zc = MSG_SPLICE_PAGES;
1073         }
1074
1075         if (unlikely(flags & MSG_FASTOPEN ||
1076                      inet_test_bit(DEFER_CONNECT, sk)) &&
1077             !tp->repair) {
1078                 err = tcp_sendmsg_fastopen(sk, msg, &copied_syn, size, uarg);
1079                 if (err == -EINPROGRESS && copied_syn > 0)
1080                         goto out;
1081                 else if (err)
1082                         goto out_err;
1083         }
1084
1085         timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
1086
1087         tcp_rate_check_app_limited(sk);  /* is sending application-limited? */
1088
1089         /* Wait for a connection to finish. One exception is TCP Fast Open
1090          * (passive side) where data is allowed to be sent before a connection
1091          * is fully established.
1092          */
1093         if (((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) &&
1094             !tcp_passive_fastopen(sk)) {
1095                 err = sk_stream_wait_connect(sk, &timeo);
1096                 if (err != 0)
1097                         goto do_error;
1098         }
1099
1100         if (unlikely(tp->repair)) {
1101                 if (tp->repair_queue == TCP_RECV_QUEUE) {
1102                         copied = tcp_send_rcvq(sk, msg, size);
1103                         goto out_nopush;
1104                 }
1105
1106                 err = -EINVAL;
1107                 if (tp->repair_queue == TCP_NO_QUEUE)
1108                         goto out_err;
1109
1110                 /* 'common' sending to sendq */
1111         }
1112
1113         sockcm_init(&sockc, sk);
1114         if (msg->msg_controllen) {
1115                 err = sock_cmsg_send(sk, msg, &sockc);
1116                 if (unlikely(err)) {
1117                         err = -EINVAL;
1118                         goto out_err;
1119                 }
1120         }
1121
1122         /* This should be in poll */
1123         sk_clear_bit(SOCKWQ_ASYNC_NOSPACE, sk);
1124
1125         /* Ok commence sending. */
1126         copied = 0;
1127
1128 restart:
1129         mss_now = tcp_send_mss(sk, &size_goal, flags);
1130
1131         err = -EPIPE;
1132         if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
1133                 goto do_error;
1134
1135         while (msg_data_left(msg)) {
1136                 ssize_t copy = 0;
1137
1138                 skb = tcp_write_queue_tail(sk);
1139                 if (skb)
1140                         copy = size_goal - skb->len;
1141
1142                 if (copy <= 0 || !tcp_skb_can_collapse_to(skb)) {
1143                         bool first_skb;
1144
1145 new_segment:
1146                         if (!sk_stream_memory_free(sk))
1147                                 goto wait_for_space;
1148
1149                         if (unlikely(process_backlog >= 16)) {
1150                                 process_backlog = 0;
1151                                 if (sk_flush_backlog(sk))
1152                                         goto restart;
1153                         }
1154                         first_skb = tcp_rtx_and_write_queues_empty(sk);
1155                         skb = tcp_stream_alloc_skb(sk, sk->sk_allocation,
1156                                                    first_skb);
1157                         if (!skb)
1158                                 goto wait_for_space;
1159
1160                         process_backlog++;
1161
1162                         tcp_skb_entail(sk, skb);
1163                         copy = size_goal;
1164
1165                         /* All packets are restored as if they have
1166                          * already been sent. skb_mstamp_ns isn't set to
1167                          * avoid wrong rtt estimation.
1168                          */
1169                         if (tp->repair)
1170                                 TCP_SKB_CB(skb)->sacked |= TCPCB_REPAIRED;
1171                 }
1172
1173                 /* Try to append data to the end of skb. */
1174                 if (copy > msg_data_left(msg))
1175                         copy = msg_data_left(msg);
1176
1177                 if (zc == 0) {
1178                         bool merge = true;
1179                         int i = skb_shinfo(skb)->nr_frags;
1180                         struct page_frag *pfrag = sk_page_frag(sk);
1181
1182                         if (!sk_page_frag_refill(sk, pfrag))
1183                                 goto wait_for_space;
1184
1185                         if (!skb_can_coalesce(skb, i, pfrag->page,
1186                                               pfrag->offset)) {
1187                                 if (i >= READ_ONCE(sysctl_max_skb_frags)) {
1188                                         tcp_mark_push(tp, skb);
1189                                         goto new_segment;
1190                                 }
1191                                 merge = false;
1192                         }
1193
1194                         copy = min_t(int, copy, pfrag->size - pfrag->offset);
1195
1196                         if (unlikely(skb_zcopy_pure(skb) || skb_zcopy_managed(skb))) {
1197                                 if (tcp_downgrade_zcopy_pure(sk, skb))
1198                                         goto wait_for_space;
1199                                 skb_zcopy_downgrade_managed(skb);
1200                         }
1201
1202                         copy = tcp_wmem_schedule(sk, copy);
1203                         if (!copy)
1204                                 goto wait_for_space;
1205
1206                         err = skb_copy_to_page_nocache(sk, &msg->msg_iter, skb,
1207                                                        pfrag->page,
1208                                                        pfrag->offset,
1209                                                        copy);
1210                         if (err)
1211                                 goto do_error;
1212
1213                         /* Update the skb. */
1214                         if (merge) {
1215                                 skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy);
1216                         } else {
1217                                 skb_fill_page_desc(skb, i, pfrag->page,
1218                                                    pfrag->offset, copy);
1219                                 page_ref_inc(pfrag->page);
1220                         }
1221                         pfrag->offset += copy;
1222                 } else if (zc == MSG_ZEROCOPY)  {
1223                         /* First append to a fragless skb builds initial
1224                          * pure zerocopy skb
1225                          */
1226                         if (!skb->len)
1227                                 skb_shinfo(skb)->flags |= SKBFL_PURE_ZEROCOPY;
1228
1229                         if (!skb_zcopy_pure(skb)) {
1230                                 copy = tcp_wmem_schedule(sk, copy);
1231                                 if (!copy)
1232                                         goto wait_for_space;
1233                         }
1234
1235                         err = skb_zerocopy_iter_stream(sk, skb, msg, copy, uarg);
1236                         if (err == -EMSGSIZE || err == -EEXIST) {
1237                                 tcp_mark_push(tp, skb);
1238                                 goto new_segment;
1239                         }
1240                         if (err < 0)
1241                                 goto do_error;
1242                         copy = err;
1243                 } else if (zc == MSG_SPLICE_PAGES) {
1244                         /* Splice in data if we can; copy if we can't. */
1245                         if (tcp_downgrade_zcopy_pure(sk, skb))
1246                                 goto wait_for_space;
1247                         copy = tcp_wmem_schedule(sk, copy);
1248                         if (!copy)
1249                                 goto wait_for_space;
1250
1251                         err = skb_splice_from_iter(skb, &msg->msg_iter, copy,
1252                                                    sk->sk_allocation);
1253                         if (err < 0) {
1254                                 if (err == -EMSGSIZE) {
1255                                         tcp_mark_push(tp, skb);
1256                                         goto new_segment;
1257                                 }
1258                                 goto do_error;
1259                         }
1260                         copy = err;
1261
1262                         if (!(flags & MSG_NO_SHARED_FRAGS))
1263                                 skb_shinfo(skb)->flags |= SKBFL_SHARED_FRAG;
1264
1265                         sk_wmem_queued_add(sk, copy);
1266                         sk_mem_charge(sk, copy);
1267                 }
1268
1269                 if (!copied)
1270                         TCP_SKB_CB(skb)->tcp_flags &= ~TCPHDR_PSH;
1271
1272                 WRITE_ONCE(tp->write_seq, tp->write_seq + copy);
1273                 TCP_SKB_CB(skb)->end_seq += copy;
1274                 tcp_skb_pcount_set(skb, 0);
1275
1276                 copied += copy;
1277                 if (!msg_data_left(msg)) {
1278                         if (unlikely(flags & MSG_EOR))
1279                                 TCP_SKB_CB(skb)->eor = 1;
1280                         goto out;
1281                 }
1282
1283                 if (skb->len < size_goal || (flags & MSG_OOB) || unlikely(tp->repair))
1284                         continue;
1285
1286                 if (forced_push(tp)) {
1287                         tcp_mark_push(tp, skb);
1288                         __tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH);
1289                 } else if (skb == tcp_send_head(sk))
1290                         tcp_push_one(sk, mss_now);
1291                 continue;
1292
1293 wait_for_space:
1294                 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
1295                 tcp_remove_empty_skb(sk);
1296                 if (copied)
1297                         tcp_push(sk, flags & ~MSG_MORE, mss_now,
1298                                  TCP_NAGLE_PUSH, size_goal);
1299
1300                 err = sk_stream_wait_memory(sk, &timeo);
1301                 if (err != 0)
1302                         goto do_error;
1303
1304                 mss_now = tcp_send_mss(sk, &size_goal, flags);
1305         }
1306
1307 out:
1308         if (copied) {
1309                 tcp_tx_timestamp(sk, sockc.tsflags);
1310                 tcp_push(sk, flags, mss_now, tp->nonagle, size_goal);
1311         }
1312 out_nopush:
1313         /* msg->msg_ubuf is pinned by the caller so we don't take extra refs */
1314         if (uarg && !msg->msg_ubuf)
1315                 net_zcopy_put(uarg);
1316         return copied + copied_syn;
1317
1318 do_error:
1319         tcp_remove_empty_skb(sk);
1320
1321         if (copied + copied_syn)
1322                 goto out;
1323 out_err:
1324         /* msg->msg_ubuf is pinned by the caller so we don't take extra refs */
1325         if (uarg && !msg->msg_ubuf)
1326                 net_zcopy_put_abort(uarg, true);
1327         err = sk_stream_error(sk, flags, err);
1328         /* make sure we wake any epoll edge trigger waiter */
1329         if (unlikely(tcp_rtx_and_write_queues_empty(sk) && err == -EAGAIN)) {
1330                 sk->sk_write_space(sk);
1331                 tcp_chrono_stop(sk, TCP_CHRONO_SNDBUF_LIMITED);
1332         }
1333         return err;
1334 }
1335 EXPORT_SYMBOL_GPL(tcp_sendmsg_locked);
1336
1337 int tcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t size)
1338 {
1339         int ret;
1340
1341         lock_sock(sk);
1342         ret = tcp_sendmsg_locked(sk, msg, size);
1343         release_sock(sk);
1344
1345         return ret;
1346 }
1347 EXPORT_SYMBOL(tcp_sendmsg);
1348
1349 void tcp_splice_eof(struct socket *sock)
1350 {
1351         struct sock *sk = sock->sk;
1352         struct tcp_sock *tp = tcp_sk(sk);
1353         int mss_now, size_goal;
1354
1355         if (!tcp_write_queue_tail(sk))
1356                 return;
1357
1358         lock_sock(sk);
1359         mss_now = tcp_send_mss(sk, &size_goal, 0);
1360         tcp_push(sk, 0, mss_now, tp->nonagle, size_goal);
1361         release_sock(sk);
1362 }
1363 EXPORT_SYMBOL_GPL(tcp_splice_eof);
1364
1365 /*
1366  *      Handle reading urgent data. BSD has very simple semantics for
1367  *      this, no blocking and very strange errors 8)
1368  */
1369
1370 static int tcp_recv_urg(struct sock *sk, struct msghdr *msg, int len, int flags)
1371 {
1372         struct tcp_sock *tp = tcp_sk(sk);
1373
1374         /* No URG data to read. */
1375         if (sock_flag(sk, SOCK_URGINLINE) || !tp->urg_data ||
1376             tp->urg_data == TCP_URG_READ)
1377                 return -EINVAL; /* Yes this is right ! */
1378
1379         if (sk->sk_state == TCP_CLOSE && !sock_flag(sk, SOCK_DONE))
1380                 return -ENOTCONN;
1381
1382         if (tp->urg_data & TCP_URG_VALID) {
1383                 int err = 0;
1384                 char c = tp->urg_data;
1385
1386                 if (!(flags & MSG_PEEK))
1387                         WRITE_ONCE(tp->urg_data, TCP_URG_READ);
1388
1389                 /* Read urgent data. */
1390                 msg->msg_flags |= MSG_OOB;
1391
1392                 if (len > 0) {
1393                         if (!(flags & MSG_TRUNC))
1394                                 err = memcpy_to_msg(msg, &c, 1);
1395                         len = 1;
1396                 } else
1397                         msg->msg_flags |= MSG_TRUNC;
1398
1399                 return err ? -EFAULT : len;
1400         }
1401
1402         if (sk->sk_state == TCP_CLOSE || (sk->sk_shutdown & RCV_SHUTDOWN))
1403                 return 0;
1404
1405         /* Fixed the recv(..., MSG_OOB) behaviour.  BSD docs and
1406          * the available implementations agree in this case:
1407          * this call should never block, independent of the
1408          * blocking state of the socket.
1409          * Mike <pall@rz.uni-karlsruhe.de>
1410          */
1411         return -EAGAIN;
1412 }
1413
1414 static int tcp_peek_sndq(struct sock *sk, struct msghdr *msg, int len)
1415 {
1416         struct sk_buff *skb;
1417         int copied = 0, err = 0;
1418
1419         /* XXX -- need to support SO_PEEK_OFF */
1420
1421         skb_rbtree_walk(skb, &sk->tcp_rtx_queue) {
1422                 err = skb_copy_datagram_msg(skb, 0, msg, skb->len);
1423                 if (err)
1424                         return err;
1425                 copied += skb->len;
1426         }
1427
1428         skb_queue_walk(&sk->sk_write_queue, skb) {
1429                 err = skb_copy_datagram_msg(skb, 0, msg, skb->len);
1430                 if (err)
1431                         break;
1432
1433                 copied += skb->len;
1434         }
1435
1436         return err ?: copied;
1437 }
1438
1439 /* Clean up the receive buffer for full frames taken by the user,
1440  * then send an ACK if necessary.  COPIED is the number of bytes
1441  * tcp_recvmsg has given to the user so far, it speeds up the
1442  * calculation of whether or not we must ACK for the sake of
1443  * a window update.
1444  */
1445 void __tcp_cleanup_rbuf(struct sock *sk, int copied)
1446 {
1447         struct tcp_sock *tp = tcp_sk(sk);
1448         bool time_to_ack = false;
1449
1450         if (inet_csk_ack_scheduled(sk)) {
1451                 const struct inet_connection_sock *icsk = inet_csk(sk);
1452
1453                 if (/* Once-per-two-segments ACK was not sent by tcp_input.c */
1454                     tp->rcv_nxt - tp->rcv_wup > icsk->icsk_ack.rcv_mss ||
1455                     /*
1456                      * If this read emptied read buffer, we send ACK, if
1457                      * connection is not bidirectional, user drained
1458                      * receive buffer and there was a small segment
1459                      * in queue.
1460                      */
1461                     (copied > 0 &&
1462                      ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED2) ||
1463                       ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED) &&
1464                        !inet_csk_in_pingpong_mode(sk))) &&
1465                       !atomic_read(&sk->sk_rmem_alloc)))
1466                         time_to_ack = true;
1467         }
1468
1469         /* We send an ACK if we can now advertise a non-zero window
1470          * which has been raised "significantly".
1471          *
1472          * Even if window raised up to infinity, do not send window open ACK
1473          * in states, where we will not receive more. It is useless.
1474          */
1475         if (copied > 0 && !time_to_ack && !(sk->sk_shutdown & RCV_SHUTDOWN)) {
1476                 __u32 rcv_window_now = tcp_receive_window(tp);
1477
1478                 /* Optimize, __tcp_select_window() is not cheap. */
1479                 if (2*rcv_window_now <= tp->window_clamp) {
1480                         __u32 new_window = __tcp_select_window(sk);
1481
1482                         /* Send ACK now, if this read freed lots of space
1483                          * in our buffer. Certainly, new_window is new window.
1484                          * We can advertise it now, if it is not less than current one.
1485                          * "Lots" means "at least twice" here.
1486                          */
1487                         if (new_window && new_window >= 2 * rcv_window_now)
1488                                 time_to_ack = true;
1489                 }
1490         }
1491         if (time_to_ack)
1492                 tcp_send_ack(sk);
1493 }
1494
1495 void tcp_cleanup_rbuf(struct sock *sk, int copied)
1496 {
1497         struct sk_buff *skb = skb_peek(&sk->sk_receive_queue);
1498         struct tcp_sock *tp = tcp_sk(sk);
1499
1500         WARN(skb && !before(tp->copied_seq, TCP_SKB_CB(skb)->end_seq),
1501              "cleanup rbuf bug: copied %X seq %X rcvnxt %X\n",
1502              tp->copied_seq, TCP_SKB_CB(skb)->end_seq, tp->rcv_nxt);
1503         __tcp_cleanup_rbuf(sk, copied);
1504 }
1505
1506 static void tcp_eat_recv_skb(struct sock *sk, struct sk_buff *skb)
1507 {
1508         __skb_unlink(skb, &sk->sk_receive_queue);
1509         if (likely(skb->destructor == sock_rfree)) {
1510                 sock_rfree(skb);
1511                 skb->destructor = NULL;
1512                 skb->sk = NULL;
1513                 return skb_attempt_defer_free(skb);
1514         }
1515         __kfree_skb(skb);
1516 }
1517
1518 struct sk_buff *tcp_recv_skb(struct sock *sk, u32 seq, u32 *off)
1519 {
1520         struct sk_buff *skb;
1521         u32 offset;
1522
1523         while ((skb = skb_peek(&sk->sk_receive_queue)) != NULL) {
1524                 offset = seq - TCP_SKB_CB(skb)->seq;
1525                 if (unlikely(TCP_SKB_CB(skb)->tcp_flags & TCPHDR_SYN)) {
1526                         pr_err_once("%s: found a SYN, please report !\n", __func__);
1527                         offset--;
1528                 }
1529                 if (offset < skb->len || (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)) {
1530                         *off = offset;
1531                         return skb;
1532                 }
1533                 /* This looks weird, but this can happen if TCP collapsing
1534                  * splitted a fat GRO packet, while we released socket lock
1535                  * in skb_splice_bits()
1536                  */
1537                 tcp_eat_recv_skb(sk, skb);
1538         }
1539         return NULL;
1540 }
1541 EXPORT_SYMBOL(tcp_recv_skb);
1542
1543 /*
1544  * This routine provides an alternative to tcp_recvmsg() for routines
1545  * that would like to handle copying from skbuffs directly in 'sendfile'
1546  * fashion.
1547  * Note:
1548  *      - It is assumed that the socket was locked by the caller.
1549  *      - The routine does not block.
1550  *      - At present, there is no support for reading OOB data
1551  *        or for 'peeking' the socket using this routine
1552  *        (although both would be easy to implement).
1553  */
1554 int tcp_read_sock(struct sock *sk, read_descriptor_t *desc,
1555                   sk_read_actor_t recv_actor)
1556 {
1557         struct sk_buff *skb;
1558         struct tcp_sock *tp = tcp_sk(sk);
1559         u32 seq = tp->copied_seq;
1560         u32 offset;
1561         int copied = 0;
1562
1563         if (sk->sk_state == TCP_LISTEN)
1564                 return -ENOTCONN;
1565         while ((skb = tcp_recv_skb(sk, seq, &offset)) != NULL) {
1566                 if (offset < skb->len) {
1567                         int used;
1568                         size_t len;
1569
1570                         len = skb->len - offset;
1571                         /* Stop reading if we hit a patch of urgent data */
1572                         if (unlikely(tp->urg_data)) {
1573                                 u32 urg_offset = tp->urg_seq - seq;
1574                                 if (urg_offset < len)
1575                                         len = urg_offset;
1576                                 if (!len)
1577                                         break;
1578                         }
1579                         used = recv_actor(desc, skb, offset, len);
1580                         if (used <= 0) {
1581                                 if (!copied)
1582                                         copied = used;
1583                                 break;
1584                         }
1585                         if (WARN_ON_ONCE(used > len))
1586                                 used = len;
1587                         seq += used;
1588                         copied += used;
1589                         offset += used;
1590
1591                         /* If recv_actor drops the lock (e.g. TCP splice
1592                          * receive) the skb pointer might be invalid when
1593                          * getting here: tcp_collapse might have deleted it
1594                          * while aggregating skbs from the socket queue.
1595                          */
1596                         skb = tcp_recv_skb(sk, seq - 1, &offset);
1597                         if (!skb)
1598                                 break;
1599                         /* TCP coalescing might have appended data to the skb.
1600                          * Try to splice more frags
1601                          */
1602                         if (offset + 1 != skb->len)
1603                                 continue;
1604                 }
1605                 if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN) {
1606                         tcp_eat_recv_skb(sk, skb);
1607                         ++seq;
1608                         break;
1609                 }
1610                 tcp_eat_recv_skb(sk, skb);
1611                 if (!desc->count)
1612                         break;
1613                 WRITE_ONCE(tp->copied_seq, seq);
1614         }
1615         WRITE_ONCE(tp->copied_seq, seq);
1616
1617         tcp_rcv_space_adjust(sk);
1618
1619         /* Clean up data we have read: This will do ACK frames. */
1620         if (copied > 0) {
1621                 tcp_recv_skb(sk, seq, &offset);
1622                 tcp_cleanup_rbuf(sk, copied);
1623         }
1624         return copied;
1625 }
1626 EXPORT_SYMBOL(tcp_read_sock);
1627
1628 int tcp_read_skb(struct sock *sk, skb_read_actor_t recv_actor)
1629 {
1630         struct sk_buff *skb;
1631         int copied = 0;
1632
1633         if (sk->sk_state == TCP_LISTEN)
1634                 return -ENOTCONN;
1635
1636         while ((skb = skb_peek(&sk->sk_receive_queue)) != NULL) {
1637                 u8 tcp_flags;
1638                 int used;
1639
1640                 __skb_unlink(skb, &sk->sk_receive_queue);
1641                 WARN_ON_ONCE(!skb_set_owner_sk_safe(skb, sk));
1642                 tcp_flags = TCP_SKB_CB(skb)->tcp_flags;
1643                 used = recv_actor(sk, skb);
1644                 if (used < 0) {
1645                         if (!copied)
1646                                 copied = used;
1647                         break;
1648                 }
1649                 copied += used;
1650
1651                 if (tcp_flags & TCPHDR_FIN)
1652                         break;
1653         }
1654         return copied;
1655 }
1656 EXPORT_SYMBOL(tcp_read_skb);
1657
1658 void tcp_read_done(struct sock *sk, size_t len)
1659 {
1660         struct tcp_sock *tp = tcp_sk(sk);
1661         u32 seq = tp->copied_seq;
1662         struct sk_buff *skb;
1663         size_t left;
1664         u32 offset;
1665
1666         if (sk->sk_state == TCP_LISTEN)
1667                 return;
1668
1669         left = len;
1670         while (left && (skb = tcp_recv_skb(sk, seq, &offset)) != NULL) {
1671                 int used;
1672
1673                 used = min_t(size_t, skb->len - offset, left);
1674                 seq += used;
1675                 left -= used;
1676
1677                 if (skb->len > offset + used)
1678                         break;
1679
1680                 if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN) {
1681                         tcp_eat_recv_skb(sk, skb);
1682                         ++seq;
1683                         break;
1684                 }
1685                 tcp_eat_recv_skb(sk, skb);
1686         }
1687         WRITE_ONCE(tp->copied_seq, seq);
1688
1689         tcp_rcv_space_adjust(sk);
1690
1691         /* Clean up data we have read: This will do ACK frames. */
1692         if (left != len)
1693                 tcp_cleanup_rbuf(sk, len - left);
1694 }
1695 EXPORT_SYMBOL(tcp_read_done);
1696
1697 int tcp_peek_len(struct socket *sock)
1698 {
1699         return tcp_inq(sock->sk);
1700 }
1701 EXPORT_SYMBOL(tcp_peek_len);
1702
1703 /* Make sure sk_rcvbuf is big enough to satisfy SO_RCVLOWAT hint */
1704 int tcp_set_rcvlowat(struct sock *sk, int val)
1705 {
1706         int space, cap;
1707
1708         if (sk->sk_userlocks & SOCK_RCVBUF_LOCK)
1709                 cap = sk->sk_rcvbuf >> 1;
1710         else
1711                 cap = READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_rmem[2]) >> 1;
1712         val = min(val, cap);
1713         WRITE_ONCE(sk->sk_rcvlowat, val ? : 1);
1714
1715         /* Check if we need to signal EPOLLIN right now */
1716         tcp_data_ready(sk);
1717
1718         if (sk->sk_userlocks & SOCK_RCVBUF_LOCK)
1719                 return 0;
1720
1721         space = tcp_space_from_win(sk, val);
1722         if (space > sk->sk_rcvbuf) {
1723                 WRITE_ONCE(sk->sk_rcvbuf, space);
1724                 tcp_sk(sk)->window_clamp = val;
1725         }
1726         return 0;
1727 }
1728 EXPORT_SYMBOL(tcp_set_rcvlowat);
1729
1730 void tcp_update_recv_tstamps(struct sk_buff *skb,
1731                              struct scm_timestamping_internal *tss)
1732 {
1733         if (skb->tstamp)
1734                 tss->ts[0] = ktime_to_timespec64(skb->tstamp);
1735         else
1736                 tss->ts[0] = (struct timespec64) {0};
1737
1738         if (skb_hwtstamps(skb)->hwtstamp)
1739                 tss->ts[2] = ktime_to_timespec64(skb_hwtstamps(skb)->hwtstamp);
1740         else
1741                 tss->ts[2] = (struct timespec64) {0};
1742 }
1743
1744 #ifdef CONFIG_MMU
1745 static const struct vm_operations_struct tcp_vm_ops = {
1746 };
1747
1748 int tcp_mmap(struct file *file, struct socket *sock,
1749              struct vm_area_struct *vma)
1750 {
1751         if (vma->vm_flags & (VM_WRITE | VM_EXEC))
1752                 return -EPERM;
1753         vm_flags_clear(vma, VM_MAYWRITE | VM_MAYEXEC);
1754
1755         /* Instruct vm_insert_page() to not mmap_read_lock(mm) */
1756         vm_flags_set(vma, VM_MIXEDMAP);
1757
1758         vma->vm_ops = &tcp_vm_ops;
1759         return 0;
1760 }
1761 EXPORT_SYMBOL(tcp_mmap);
1762
1763 static skb_frag_t *skb_advance_to_frag(struct sk_buff *skb, u32 offset_skb,
1764                                        u32 *offset_frag)
1765 {
1766         skb_frag_t *frag;
1767
1768         if (unlikely(offset_skb >= skb->len))
1769                 return NULL;
1770
1771         offset_skb -= skb_headlen(skb);
1772         if ((int)offset_skb < 0 || skb_has_frag_list(skb))
1773                 return NULL;
1774
1775         frag = skb_shinfo(skb)->frags;
1776         while (offset_skb) {
1777                 if (skb_frag_size(frag) > offset_skb) {
1778                         *offset_frag = offset_skb;
1779                         return frag;
1780                 }
1781                 offset_skb -= skb_frag_size(frag);
1782                 ++frag;
1783         }
1784         *offset_frag = 0;
1785         return frag;
1786 }
1787
1788 static bool can_map_frag(const skb_frag_t *frag)
1789 {
1790         struct page *page;
1791
1792         if (skb_frag_size(frag) != PAGE_SIZE || skb_frag_off(frag))
1793                 return false;
1794
1795         page = skb_frag_page(frag);
1796
1797         if (PageCompound(page) || page->mapping)
1798                 return false;
1799
1800         return true;
1801 }
1802
1803 static int find_next_mappable_frag(const skb_frag_t *frag,
1804                                    int remaining_in_skb)
1805 {
1806         int offset = 0;
1807
1808         if (likely(can_map_frag(frag)))
1809                 return 0;
1810
1811         while (offset < remaining_in_skb && !can_map_frag(frag)) {
1812                 offset += skb_frag_size(frag);
1813                 ++frag;
1814         }
1815         return offset;
1816 }
1817
1818 static void tcp_zerocopy_set_hint_for_skb(struct sock *sk,
1819                                           struct tcp_zerocopy_receive *zc,
1820                                           struct sk_buff *skb, u32 offset)
1821 {
1822         u32 frag_offset, partial_frag_remainder = 0;
1823         int mappable_offset;
1824         skb_frag_t *frag;
1825
1826         /* worst case: skip to next skb. try to improve on this case below */
1827         zc->recv_skip_hint = skb->len - offset;
1828
1829         /* Find the frag containing this offset (and how far into that frag) */
1830         frag = skb_advance_to_frag(skb, offset, &frag_offset);
1831         if (!frag)
1832                 return;
1833
1834         if (frag_offset) {
1835                 struct skb_shared_info *info = skb_shinfo(skb);
1836
1837                 /* We read part of the last frag, must recvmsg() rest of skb. */
1838                 if (frag == &info->frags[info->nr_frags - 1])
1839                         return;
1840
1841                 /* Else, we must at least read the remainder in this frag. */
1842                 partial_frag_remainder = skb_frag_size(frag) - frag_offset;
1843                 zc->recv_skip_hint -= partial_frag_remainder;
1844                 ++frag;
1845         }
1846
1847         /* partial_frag_remainder: If part way through a frag, must read rest.
1848          * mappable_offset: Bytes till next mappable frag, *not* counting bytes
1849          * in partial_frag_remainder.
1850          */
1851         mappable_offset = find_next_mappable_frag(frag, zc->recv_skip_hint);
1852         zc->recv_skip_hint = mappable_offset + partial_frag_remainder;
1853 }
1854
1855 static int tcp_recvmsg_locked(struct sock *sk, struct msghdr *msg, size_t len,
1856                               int flags, struct scm_timestamping_internal *tss,
1857                               int *cmsg_flags);
1858 static int receive_fallback_to_copy(struct sock *sk,
1859                                     struct tcp_zerocopy_receive *zc, int inq,
1860                                     struct scm_timestamping_internal *tss)
1861 {
1862         unsigned long copy_address = (unsigned long)zc->copybuf_address;
1863         struct msghdr msg = {};
1864         int err;
1865
1866         zc->length = 0;
1867         zc->recv_skip_hint = 0;
1868
1869         if (copy_address != zc->copybuf_address)
1870                 return -EINVAL;
1871
1872         err = import_ubuf(ITER_DEST, (void __user *)copy_address, inq,
1873                           &msg.msg_iter);
1874         if (err)
1875                 return err;
1876
1877         err = tcp_recvmsg_locked(sk, &msg, inq, MSG_DONTWAIT,
1878                                  tss, &zc->msg_flags);
1879         if (err < 0)
1880                 return err;
1881
1882         zc->copybuf_len = err;
1883         if (likely(zc->copybuf_len)) {
1884                 struct sk_buff *skb;
1885                 u32 offset;
1886
1887                 skb = tcp_recv_skb(sk, tcp_sk(sk)->copied_seq, &offset);
1888                 if (skb)
1889                         tcp_zerocopy_set_hint_for_skb(sk, zc, skb, offset);
1890         }
1891         return 0;
1892 }
1893
1894 static int tcp_copy_straggler_data(struct tcp_zerocopy_receive *zc,
1895                                    struct sk_buff *skb, u32 copylen,
1896                                    u32 *offset, u32 *seq)
1897 {
1898         unsigned long copy_address = (unsigned long)zc->copybuf_address;
1899         struct msghdr msg = {};
1900         int err;
1901
1902         if (copy_address != zc->copybuf_address)
1903                 return -EINVAL;
1904
1905         err = import_ubuf(ITER_DEST, (void __user *)copy_address, copylen,
1906                           &msg.msg_iter);
1907         if (err)
1908                 return err;
1909         err = skb_copy_datagram_msg(skb, *offset, &msg, copylen);
1910         if (err)
1911                 return err;
1912         zc->recv_skip_hint -= copylen;
1913         *offset += copylen;
1914         *seq += copylen;
1915         return (__s32)copylen;
1916 }
1917
1918 static int tcp_zc_handle_leftover(struct tcp_zerocopy_receive *zc,
1919                                   struct sock *sk,
1920                                   struct sk_buff *skb,
1921                                   u32 *seq,
1922                                   s32 copybuf_len,
1923                                   struct scm_timestamping_internal *tss)
1924 {
1925         u32 offset, copylen = min_t(u32, copybuf_len, zc->recv_skip_hint);
1926
1927         if (!copylen)
1928                 return 0;
1929         /* skb is null if inq < PAGE_SIZE. */
1930         if (skb) {
1931                 offset = *seq - TCP_SKB_CB(skb)->seq;
1932         } else {
1933                 skb = tcp_recv_skb(sk, *seq, &offset);
1934                 if (TCP_SKB_CB(skb)->has_rxtstamp) {
1935                         tcp_update_recv_tstamps(skb, tss);
1936                         zc->msg_flags |= TCP_CMSG_TS;
1937                 }
1938         }
1939
1940         zc->copybuf_len = tcp_copy_straggler_data(zc, skb, copylen, &offset,
1941                                                   seq);
1942         return zc->copybuf_len < 0 ? 0 : copylen;
1943 }
1944
1945 static int tcp_zerocopy_vm_insert_batch_error(struct vm_area_struct *vma,
1946                                               struct page **pending_pages,
1947                                               unsigned long pages_remaining,
1948                                               unsigned long *address,
1949                                               u32 *length,
1950                                               u32 *seq,
1951                                               struct tcp_zerocopy_receive *zc,
1952                                               u32 total_bytes_to_map,
1953                                               int err)
1954 {
1955         /* At least one page did not map. Try zapping if we skipped earlier. */
1956         if (err == -EBUSY &&
1957             zc->flags & TCP_RECEIVE_ZEROCOPY_FLAG_TLB_CLEAN_HINT) {
1958                 u32 maybe_zap_len;
1959
1960                 maybe_zap_len = total_bytes_to_map -  /* All bytes to map */
1961                                 *length + /* Mapped or pending */
1962                                 (pages_remaining * PAGE_SIZE); /* Failed map. */
1963                 zap_page_range_single(vma, *address, maybe_zap_len, NULL);
1964                 err = 0;
1965         }
1966
1967         if (!err) {
1968                 unsigned long leftover_pages = pages_remaining;
1969                 int bytes_mapped;
1970
1971                 /* We called zap_page_range_single, try to reinsert. */
1972                 err = vm_insert_pages(vma, *address,
1973                                       pending_pages,
1974                                       &pages_remaining);
1975                 bytes_mapped = PAGE_SIZE * (leftover_pages - pages_remaining);
1976                 *seq += bytes_mapped;
1977                 *address += bytes_mapped;
1978         }
1979         if (err) {
1980                 /* Either we were unable to zap, OR we zapped, retried an
1981                  * insert, and still had an issue. Either ways, pages_remaining
1982                  * is the number of pages we were unable to map, and we unroll
1983                  * some state we speculatively touched before.
1984                  */
1985                 const int bytes_not_mapped = PAGE_SIZE * pages_remaining;
1986
1987                 *length -= bytes_not_mapped;
1988                 zc->recv_skip_hint += bytes_not_mapped;
1989         }
1990         return err;
1991 }
1992
1993 static int tcp_zerocopy_vm_insert_batch(struct vm_area_struct *vma,
1994                                         struct page **pages,
1995                                         unsigned int pages_to_map,
1996                                         unsigned long *address,
1997                                         u32 *length,
1998                                         u32 *seq,
1999                                         struct tcp_zerocopy_receive *zc,
2000                                         u32 total_bytes_to_map)
2001 {
2002         unsigned long pages_remaining = pages_to_map;
2003         unsigned int pages_mapped;
2004         unsigned int bytes_mapped;
2005         int err;
2006
2007         err = vm_insert_pages(vma, *address, pages, &pages_remaining);
2008         pages_mapped = pages_to_map - (unsigned int)pages_remaining;
2009         bytes_mapped = PAGE_SIZE * pages_mapped;
2010         /* Even if vm_insert_pages fails, it may have partially succeeded in
2011          * mapping (some but not all of the pages).
2012          */
2013         *seq += bytes_mapped;
2014         *address += bytes_mapped;
2015
2016         if (likely(!err))
2017                 return 0;
2018
2019         /* Error: maybe zap and retry + rollback state for failed inserts. */
2020         return tcp_zerocopy_vm_insert_batch_error(vma, pages + pages_mapped,
2021                 pages_remaining, address, length, seq, zc, total_bytes_to_map,
2022                 err);
2023 }
2024
2025 #define TCP_VALID_ZC_MSG_FLAGS   (TCP_CMSG_TS)
2026 static void tcp_zc_finalize_rx_tstamp(struct sock *sk,
2027                                       struct tcp_zerocopy_receive *zc,
2028                                       struct scm_timestamping_internal *tss)
2029 {
2030         unsigned long msg_control_addr;
2031         struct msghdr cmsg_dummy;
2032
2033         msg_control_addr = (unsigned long)zc->msg_control;
2034         cmsg_dummy.msg_control_user = (void __user *)msg_control_addr;
2035         cmsg_dummy.msg_controllen =
2036                 (__kernel_size_t)zc->msg_controllen;
2037         cmsg_dummy.msg_flags = in_compat_syscall()
2038                 ? MSG_CMSG_COMPAT : 0;
2039         cmsg_dummy.msg_control_is_user = true;
2040         zc->msg_flags = 0;
2041         if (zc->msg_control == msg_control_addr &&
2042             zc->msg_controllen == cmsg_dummy.msg_controllen) {
2043                 tcp_recv_timestamp(&cmsg_dummy, sk, tss);
2044                 zc->msg_control = (__u64)
2045                         ((uintptr_t)cmsg_dummy.msg_control_user);
2046                 zc->msg_controllen =
2047                         (__u64)cmsg_dummy.msg_controllen;
2048                 zc->msg_flags = (__u32)cmsg_dummy.msg_flags;
2049         }
2050 }
2051
2052 static struct vm_area_struct *find_tcp_vma(struct mm_struct *mm,
2053                                            unsigned long address,
2054                                            bool *mmap_locked)
2055 {
2056         struct vm_area_struct *vma = lock_vma_under_rcu(mm, address);
2057
2058         if (vma) {
2059                 if (vma->vm_ops != &tcp_vm_ops) {
2060                         vma_end_read(vma);
2061                         return NULL;
2062                 }
2063                 *mmap_locked = false;
2064                 return vma;
2065         }
2066
2067         mmap_read_lock(mm);
2068         vma = vma_lookup(mm, address);
2069         if (!vma || vma->vm_ops != &tcp_vm_ops) {
2070                 mmap_read_unlock(mm);
2071                 return NULL;
2072         }
2073         *mmap_locked = true;
2074         return vma;
2075 }
2076
2077 #define TCP_ZEROCOPY_PAGE_BATCH_SIZE 32
2078 static int tcp_zerocopy_receive(struct sock *sk,
2079                                 struct tcp_zerocopy_receive *zc,
2080                                 struct scm_timestamping_internal *tss)
2081 {
2082         u32 length = 0, offset, vma_len, avail_len, copylen = 0;
2083         unsigned long address = (unsigned long)zc->address;
2084         struct page *pages[TCP_ZEROCOPY_PAGE_BATCH_SIZE];
2085         s32 copybuf_len = zc->copybuf_len;
2086         struct tcp_sock *tp = tcp_sk(sk);
2087         const skb_frag_t *frags = NULL;
2088         unsigned int pages_to_map = 0;
2089         struct vm_area_struct *vma;
2090         struct sk_buff *skb = NULL;
2091         u32 seq = tp->copied_seq;
2092         u32 total_bytes_to_map;
2093         int inq = tcp_inq(sk);
2094         bool mmap_locked;
2095         int ret;
2096
2097         zc->copybuf_len = 0;
2098         zc->msg_flags = 0;
2099
2100         if (address & (PAGE_SIZE - 1) || address != zc->address)
2101                 return -EINVAL;
2102
2103         if (sk->sk_state == TCP_LISTEN)
2104                 return -ENOTCONN;
2105
2106         sock_rps_record_flow(sk);
2107
2108         if (inq && inq <= copybuf_len)
2109                 return receive_fallback_to_copy(sk, zc, inq, tss);
2110
2111         if (inq < PAGE_SIZE) {
2112                 zc->length = 0;
2113                 zc->recv_skip_hint = inq;
2114                 if (!inq && sock_flag(sk, SOCK_DONE))
2115                         return -EIO;
2116                 return 0;
2117         }
2118
2119         vma = find_tcp_vma(current->mm, address, &mmap_locked);
2120         if (!vma)
2121                 return -EINVAL;
2122
2123         vma_len = min_t(unsigned long, zc->length, vma->vm_end - address);
2124         avail_len = min_t(u32, vma_len, inq);
2125         total_bytes_to_map = avail_len & ~(PAGE_SIZE - 1);
2126         if (total_bytes_to_map) {
2127                 if (!(zc->flags & TCP_RECEIVE_ZEROCOPY_FLAG_TLB_CLEAN_HINT))
2128                         zap_page_range_single(vma, address, total_bytes_to_map,
2129                                               NULL);
2130                 zc->length = total_bytes_to_map;
2131                 zc->recv_skip_hint = 0;
2132         } else {
2133                 zc->length = avail_len;
2134                 zc->recv_skip_hint = avail_len;
2135         }
2136         ret = 0;
2137         while (length + PAGE_SIZE <= zc->length) {
2138                 int mappable_offset;
2139                 struct page *page;
2140
2141                 if (zc->recv_skip_hint < PAGE_SIZE) {
2142                         u32 offset_frag;
2143
2144                         if (skb) {
2145                                 if (zc->recv_skip_hint > 0)
2146                                         break;
2147                                 skb = skb->next;
2148                                 offset = seq - TCP_SKB_CB(skb)->seq;
2149                         } else {
2150                                 skb = tcp_recv_skb(sk, seq, &offset);
2151                         }
2152
2153                         if (TCP_SKB_CB(skb)->has_rxtstamp) {
2154                                 tcp_update_recv_tstamps(skb, tss);
2155                                 zc->msg_flags |= TCP_CMSG_TS;
2156                         }
2157                         zc->recv_skip_hint = skb->len - offset;
2158                         frags = skb_advance_to_frag(skb, offset, &offset_frag);
2159                         if (!frags || offset_frag)
2160                                 break;
2161                 }
2162
2163                 mappable_offset = find_next_mappable_frag(frags,
2164                                                           zc->recv_skip_hint);
2165                 if (mappable_offset) {
2166                         zc->recv_skip_hint = mappable_offset;
2167                         break;
2168                 }
2169                 page = skb_frag_page(frags);
2170                 prefetchw(page);
2171                 pages[pages_to_map++] = page;
2172                 length += PAGE_SIZE;
2173                 zc->recv_skip_hint -= PAGE_SIZE;
2174                 frags++;
2175                 if (pages_to_map == TCP_ZEROCOPY_PAGE_BATCH_SIZE ||
2176                     zc->recv_skip_hint < PAGE_SIZE) {
2177                         /* Either full batch, or we're about to go to next skb
2178                          * (and we cannot unroll failed ops across skbs).
2179                          */
2180                         ret = tcp_zerocopy_vm_insert_batch(vma, pages,
2181                                                            pages_to_map,
2182                                                            &address, &length,
2183                                                            &seq, zc,
2184                                                            total_bytes_to_map);
2185                         if (ret)
2186                                 goto out;
2187                         pages_to_map = 0;
2188                 }
2189         }
2190         if (pages_to_map) {
2191                 ret = tcp_zerocopy_vm_insert_batch(vma, pages, pages_to_map,
2192                                                    &address, &length, &seq,
2193                                                    zc, total_bytes_to_map);
2194         }
2195 out:
2196         if (mmap_locked)
2197                 mmap_read_unlock(current->mm);
2198         else
2199                 vma_end_read(vma);
2200         /* Try to copy straggler data. */
2201         if (!ret)
2202                 copylen = tcp_zc_handle_leftover(zc, sk, skb, &seq, copybuf_len, tss);
2203
2204         if (length + copylen) {
2205                 WRITE_ONCE(tp->copied_seq, seq);
2206                 tcp_rcv_space_adjust(sk);
2207
2208                 /* Clean up data we have read: This will do ACK frames. */
2209                 tcp_recv_skb(sk, seq, &offset);
2210                 tcp_cleanup_rbuf(sk, length + copylen);
2211                 ret = 0;
2212                 if (length == zc->length)
2213                         zc->recv_skip_hint = 0;
2214         } else {
2215                 if (!zc->recv_skip_hint && sock_flag(sk, SOCK_DONE))
2216                         ret = -EIO;
2217         }
2218         zc->length = length;
2219         return ret;
2220 }
2221 #endif
2222
2223 /* Similar to __sock_recv_timestamp, but does not require an skb */
2224 void tcp_recv_timestamp(struct msghdr *msg, const struct sock *sk,
2225                         struct scm_timestamping_internal *tss)
2226 {
2227         int new_tstamp = sock_flag(sk, SOCK_TSTAMP_NEW);
2228         bool has_timestamping = false;
2229
2230         if (tss->ts[0].tv_sec || tss->ts[0].tv_nsec) {
2231                 if (sock_flag(sk, SOCK_RCVTSTAMP)) {
2232                         if (sock_flag(sk, SOCK_RCVTSTAMPNS)) {
2233                                 if (new_tstamp) {
2234                                         struct __kernel_timespec kts = {
2235                                                 .tv_sec = tss->ts[0].tv_sec,
2236                                                 .tv_nsec = tss->ts[0].tv_nsec,
2237                                         };
2238                                         put_cmsg(msg, SOL_SOCKET, SO_TIMESTAMPNS_NEW,
2239                                                  sizeof(kts), &kts);
2240                                 } else {
2241                                         struct __kernel_old_timespec ts_old = {
2242                                                 .tv_sec = tss->ts[0].tv_sec,
2243                                                 .tv_nsec = tss->ts[0].tv_nsec,
2244                                         };
2245                                         put_cmsg(msg, SOL_SOCKET, SO_TIMESTAMPNS_OLD,
2246                                                  sizeof(ts_old), &ts_old);
2247                                 }
2248                         } else {
2249                                 if (new_tstamp) {
2250                                         struct __kernel_sock_timeval stv = {
2251                                                 .tv_sec = tss->ts[0].tv_sec,
2252                                                 .tv_usec = tss->ts[0].tv_nsec / 1000,
2253                                         };
2254                                         put_cmsg(msg, SOL_SOCKET, SO_TIMESTAMP_NEW,
2255                                                  sizeof(stv), &stv);
2256                                 } else {
2257                                         struct __kernel_old_timeval tv = {
2258                                                 .tv_sec = tss->ts[0].tv_sec,
2259                                                 .tv_usec = tss->ts[0].tv_nsec / 1000,
2260                                         };
2261                                         put_cmsg(msg, SOL_SOCKET, SO_TIMESTAMP_OLD,
2262                                                  sizeof(tv), &tv);
2263                                 }
2264                         }
2265                 }
2266
2267                 if (READ_ONCE(sk->sk_tsflags) & SOF_TIMESTAMPING_SOFTWARE)
2268                         has_timestamping = true;
2269                 else
2270                         tss->ts[0] = (struct timespec64) {0};
2271         }
2272
2273         if (tss->ts[2].tv_sec || tss->ts[2].tv_nsec) {
2274                 if (READ_ONCE(sk->sk_tsflags) & SOF_TIMESTAMPING_RAW_HARDWARE)
2275                         has_timestamping = true;
2276                 else
2277                         tss->ts[2] = (struct timespec64) {0};
2278         }
2279
2280         if (has_timestamping) {
2281                 tss->ts[1] = (struct timespec64) {0};
2282                 if (sock_flag(sk, SOCK_TSTAMP_NEW))
2283                         put_cmsg_scm_timestamping64(msg, tss);
2284                 else
2285                         put_cmsg_scm_timestamping(msg, tss);
2286         }
2287 }
2288
2289 static int tcp_inq_hint(struct sock *sk)
2290 {
2291         const struct tcp_sock *tp = tcp_sk(sk);
2292         u32 copied_seq = READ_ONCE(tp->copied_seq);
2293         u32 rcv_nxt = READ_ONCE(tp->rcv_nxt);
2294         int inq;
2295
2296         inq = rcv_nxt - copied_seq;
2297         if (unlikely(inq < 0 || copied_seq != READ_ONCE(tp->copied_seq))) {
2298                 lock_sock(sk);
2299                 inq = tp->rcv_nxt - tp->copied_seq;
2300                 release_sock(sk);
2301         }
2302         /* After receiving a FIN, tell the user-space to continue reading
2303          * by returning a non-zero inq.
2304          */
2305         if (inq == 0 && sock_flag(sk, SOCK_DONE))
2306                 inq = 1;
2307         return inq;
2308 }
2309
2310 /*
2311  *      This routine copies from a sock struct into the user buffer.
2312  *
2313  *      Technical note: in 2.3 we work on _locked_ socket, so that
2314  *      tricks with *seq access order and skb->users are not required.
2315  *      Probably, code can be easily improved even more.
2316  */
2317
2318 static int tcp_recvmsg_locked(struct sock *sk, struct msghdr *msg, size_t len,
2319                               int flags, struct scm_timestamping_internal *tss,
2320                               int *cmsg_flags)
2321 {
2322         struct tcp_sock *tp = tcp_sk(sk);
2323         int copied = 0;
2324         u32 peek_seq;
2325         u32 *seq;
2326         unsigned long used;
2327         int err;
2328         int target;             /* Read at least this many bytes */
2329         long timeo;
2330         struct sk_buff *skb, *last;
2331         u32 urg_hole = 0;
2332
2333         err = -ENOTCONN;
2334         if (sk->sk_state == TCP_LISTEN)
2335                 goto out;
2336
2337         if (tp->recvmsg_inq) {
2338                 *cmsg_flags = TCP_CMSG_INQ;
2339                 msg->msg_get_inq = 1;
2340         }
2341         timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);
2342
2343         /* Urgent data needs to be handled specially. */
2344         if (flags & MSG_OOB)
2345                 goto recv_urg;
2346
2347         if (unlikely(tp->repair)) {
2348                 err = -EPERM;
2349                 if (!(flags & MSG_PEEK))
2350                         goto out;
2351
2352                 if (tp->repair_queue == TCP_SEND_QUEUE)
2353                         goto recv_sndq;
2354
2355                 err = -EINVAL;
2356                 if (tp->repair_queue == TCP_NO_QUEUE)
2357                         goto out;
2358
2359                 /* 'common' recv queue MSG_PEEK-ing */
2360         }
2361
2362         seq = &tp->copied_seq;
2363         if (flags & MSG_PEEK) {
2364                 peek_seq = tp->copied_seq;
2365                 seq = &peek_seq;
2366         }
2367
2368         target = sock_rcvlowat(sk, flags & MSG_WAITALL, len);
2369
2370         do {
2371                 u32 offset;
2372
2373                 /* Are we at urgent data? Stop if we have read anything or have SIGURG pending. */
2374                 if (unlikely(tp->urg_data) && tp->urg_seq == *seq) {
2375                         if (copied)
2376                                 break;
2377                         if (signal_pending(current)) {
2378                                 copied = timeo ? sock_intr_errno(timeo) : -EAGAIN;
2379                                 break;
2380                         }
2381                 }
2382
2383                 /* Next get a buffer. */
2384
2385                 last = skb_peek_tail(&sk->sk_receive_queue);
2386                 skb_queue_walk(&sk->sk_receive_queue, skb) {
2387                         last = skb;
2388                         /* Now that we have two receive queues this
2389                          * shouldn't happen.
2390                          */
2391                         if (WARN(before(*seq, TCP_SKB_CB(skb)->seq),
2392                                  "TCP recvmsg seq # bug: copied %X, seq %X, rcvnxt %X, fl %X\n",
2393                                  *seq, TCP_SKB_CB(skb)->seq, tp->rcv_nxt,
2394                                  flags))
2395                                 break;
2396
2397                         offset = *seq - TCP_SKB_CB(skb)->seq;
2398                         if (unlikely(TCP_SKB_CB(skb)->tcp_flags & TCPHDR_SYN)) {
2399                                 pr_err_once("%s: found a SYN, please report !\n", __func__);
2400                                 offset--;
2401                         }
2402                         if (offset < skb->len)
2403                                 goto found_ok_skb;
2404                         if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)
2405                                 goto found_fin_ok;
2406                         WARN(!(flags & MSG_PEEK),
2407                              "TCP recvmsg seq # bug 2: copied %X, seq %X, rcvnxt %X, fl %X\n",
2408                              *seq, TCP_SKB_CB(skb)->seq, tp->rcv_nxt, flags);
2409                 }
2410
2411                 /* Well, if we have backlog, try to process it now yet. */
2412
2413                 if (copied >= target && !READ_ONCE(sk->sk_backlog.tail))
2414                         break;
2415
2416                 if (copied) {
2417                         if (!timeo ||
2418                             sk->sk_err ||
2419                             sk->sk_state == TCP_CLOSE ||
2420                             (sk->sk_shutdown & RCV_SHUTDOWN) ||
2421                             signal_pending(current))
2422                                 break;
2423                 } else {
2424                         if (sock_flag(sk, SOCK_DONE))
2425                                 break;
2426
2427                         if (sk->sk_err) {
2428                                 copied = sock_error(sk);
2429                                 break;
2430                         }
2431
2432                         if (sk->sk_shutdown & RCV_SHUTDOWN)
2433                                 break;
2434
2435                         if (sk->sk_state == TCP_CLOSE) {
2436                                 /* This occurs when user tries to read
2437                                  * from never connected socket.
2438                                  */
2439                                 copied = -ENOTCONN;
2440                                 break;
2441                         }
2442
2443                         if (!timeo) {
2444                                 copied = -EAGAIN;
2445                                 break;
2446                         }
2447
2448                         if (signal_pending(current)) {
2449                                 copied = sock_intr_errno(timeo);
2450                                 break;
2451                         }
2452                 }
2453
2454                 if (copied >= target) {
2455                         /* Do not sleep, just process backlog. */
2456                         __sk_flush_backlog(sk);
2457                 } else {
2458                         tcp_cleanup_rbuf(sk, copied);
2459                         err = sk_wait_data(sk, &timeo, last);
2460                         if (err < 0) {
2461                                 err = copied ? : err;
2462                                 goto out;
2463                         }
2464                 }
2465
2466                 if ((flags & MSG_PEEK) &&
2467                     (peek_seq - copied - urg_hole != tp->copied_seq)) {
2468                         net_dbg_ratelimited("TCP(%s:%d): Application bug, race in MSG_PEEK\n",
2469                                             current->comm,
2470                                             task_pid_nr(current));
2471                         peek_seq = tp->copied_seq;
2472                 }
2473                 continue;
2474
2475 found_ok_skb:
2476                 /* Ok so how much can we use? */
2477                 used = skb->len - offset;
2478                 if (len < used)
2479                         used = len;
2480
2481                 /* Do we have urgent data here? */
2482                 if (unlikely(tp->urg_data)) {
2483                         u32 urg_offset = tp->urg_seq - *seq;
2484                         if (urg_offset < used) {
2485                                 if (!urg_offset) {
2486                                         if (!sock_flag(sk, SOCK_URGINLINE)) {
2487                                                 WRITE_ONCE(*seq, *seq + 1);
2488                                                 urg_hole++;
2489                                                 offset++;
2490                                                 used--;
2491                                                 if (!used)
2492                                                         goto skip_copy;
2493                                         }
2494                                 } else
2495                                         used = urg_offset;
2496                         }
2497                 }
2498
2499                 if (!(flags & MSG_TRUNC)) {
2500                         err = skb_copy_datagram_msg(skb, offset, msg, used);
2501                         if (err) {
2502                                 /* Exception. Bailout! */
2503                                 if (!copied)
2504                                         copied = -EFAULT;
2505                                 break;
2506                         }
2507                 }
2508
2509                 WRITE_ONCE(*seq, *seq + used);
2510                 copied += used;
2511                 len -= used;
2512
2513                 tcp_rcv_space_adjust(sk);
2514
2515 skip_copy:
2516                 if (unlikely(tp->urg_data) && after(tp->copied_seq, tp->urg_seq)) {
2517                         WRITE_ONCE(tp->urg_data, 0);
2518                         tcp_fast_path_check(sk);
2519                 }
2520
2521                 if (TCP_SKB_CB(skb)->has_rxtstamp) {
2522                         tcp_update_recv_tstamps(skb, tss);
2523                         *cmsg_flags |= TCP_CMSG_TS;
2524                 }
2525
2526                 if (used + offset < skb->len)
2527                         continue;
2528
2529                 if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)
2530                         goto found_fin_ok;
2531                 if (!(flags & MSG_PEEK))
2532                         tcp_eat_recv_skb(sk, skb);
2533                 continue;
2534
2535 found_fin_ok:
2536                 /* Process the FIN. */
2537                 WRITE_ONCE(*seq, *seq + 1);
2538                 if (!(flags & MSG_PEEK))
2539                         tcp_eat_recv_skb(sk, skb);
2540                 break;
2541         } while (len > 0);
2542
2543         /* According to UNIX98, msg_name/msg_namelen are ignored
2544          * on connected socket. I was just happy when found this 8) --ANK
2545          */
2546
2547         /* Clean up data we have read: This will do ACK frames. */
2548         tcp_cleanup_rbuf(sk, copied);
2549         return copied;
2550
2551 out:
2552         return err;
2553
2554 recv_urg:
2555         err = tcp_recv_urg(sk, msg, len, flags);
2556         goto out;
2557
2558 recv_sndq:
2559         err = tcp_peek_sndq(sk, msg, len);
2560         goto out;
2561 }
2562
2563 int tcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int flags,
2564                 int *addr_len)
2565 {
2566         int cmsg_flags = 0, ret;
2567         struct scm_timestamping_internal tss;
2568
2569         if (unlikely(flags & MSG_ERRQUEUE))
2570                 return inet_recv_error(sk, msg, len, addr_len);
2571
2572         if (sk_can_busy_loop(sk) &&
2573             skb_queue_empty_lockless(&sk->sk_receive_queue) &&
2574             sk->sk_state == TCP_ESTABLISHED)
2575                 sk_busy_loop(sk, flags & MSG_DONTWAIT);
2576
2577         lock_sock(sk);
2578         ret = tcp_recvmsg_locked(sk, msg, len, flags, &tss, &cmsg_flags);
2579         release_sock(sk);
2580
2581         if ((cmsg_flags || msg->msg_get_inq) && ret >= 0) {
2582                 if (cmsg_flags & TCP_CMSG_TS)
2583                         tcp_recv_timestamp(msg, sk, &tss);
2584                 if (msg->msg_get_inq) {
2585                         msg->msg_inq = tcp_inq_hint(sk);
2586                         if (cmsg_flags & TCP_CMSG_INQ)
2587                                 put_cmsg(msg, SOL_TCP, TCP_CM_INQ,
2588                                          sizeof(msg->msg_inq), &msg->msg_inq);
2589                 }
2590         }
2591         return ret;
2592 }
2593 EXPORT_SYMBOL(tcp_recvmsg);
2594
2595 void tcp_set_state(struct sock *sk, int state)
2596 {
2597         int oldstate = sk->sk_state;
2598
2599         /* We defined a new enum for TCP states that are exported in BPF
2600          * so as not force the internal TCP states to be frozen. The
2601          * following checks will detect if an internal state value ever
2602          * differs from the BPF value. If this ever happens, then we will
2603          * need to remap the internal value to the BPF value before calling
2604          * tcp_call_bpf_2arg.
2605          */
2606         BUILD_BUG_ON((int)BPF_TCP_ESTABLISHED != (int)TCP_ESTABLISHED);
2607         BUILD_BUG_ON((int)BPF_TCP_SYN_SENT != (int)TCP_SYN_SENT);
2608         BUILD_BUG_ON((int)BPF_TCP_SYN_RECV != (int)TCP_SYN_RECV);
2609         BUILD_BUG_ON((int)BPF_TCP_FIN_WAIT1 != (int)TCP_FIN_WAIT1);
2610         BUILD_BUG_ON((int)BPF_TCP_FIN_WAIT2 != (int)TCP_FIN_WAIT2);
2611         BUILD_BUG_ON((int)BPF_TCP_TIME_WAIT != (int)TCP_TIME_WAIT);
2612         BUILD_BUG_ON((int)BPF_TCP_CLOSE != (int)TCP_CLOSE);
2613         BUILD_BUG_ON((int)BPF_TCP_CLOSE_WAIT != (int)TCP_CLOSE_WAIT);
2614         BUILD_BUG_ON((int)BPF_TCP_LAST_ACK != (int)TCP_LAST_ACK);
2615         BUILD_BUG_ON((int)BPF_TCP_LISTEN != (int)TCP_LISTEN);
2616         BUILD_BUG_ON((int)BPF_TCP_CLOSING != (int)TCP_CLOSING);
2617         BUILD_BUG_ON((int)BPF_TCP_NEW_SYN_RECV != (int)TCP_NEW_SYN_RECV);
2618         BUILD_BUG_ON((int)BPF_TCP_BOUND_INACTIVE != (int)TCP_BOUND_INACTIVE);
2619         BUILD_BUG_ON((int)BPF_TCP_MAX_STATES != (int)TCP_MAX_STATES);
2620
2621         /* bpf uapi header bpf.h defines an anonymous enum with values
2622          * BPF_TCP_* used by bpf programs. Currently gcc built vmlinux
2623          * is able to emit this enum in DWARF due to the above BUILD_BUG_ON.
2624          * But clang built vmlinux does not have this enum in DWARF
2625          * since clang removes the above code before generating IR/debuginfo.
2626          * Let us explicitly emit the type debuginfo to ensure the
2627          * above-mentioned anonymous enum in the vmlinux DWARF and hence BTF
2628          * regardless of which compiler is used.
2629          */
2630         BTF_TYPE_EMIT_ENUM(BPF_TCP_ESTABLISHED);
2631
2632         if (BPF_SOCK_OPS_TEST_FLAG(tcp_sk(sk), BPF_SOCK_OPS_STATE_CB_FLAG))
2633                 tcp_call_bpf_2arg(sk, BPF_SOCK_OPS_STATE_CB, oldstate, state);
2634
2635         switch (state) {
2636         case TCP_ESTABLISHED:
2637                 if (oldstate != TCP_ESTABLISHED)
2638                         TCP_INC_STATS(sock_net(sk), TCP_MIB_CURRESTAB);
2639                 break;
2640
2641         case TCP_CLOSE:
2642                 if (oldstate == TCP_CLOSE_WAIT || oldstate == TCP_ESTABLISHED)
2643                         TCP_INC_STATS(sock_net(sk), TCP_MIB_ESTABRESETS);
2644
2645                 sk->sk_prot->unhash(sk);
2646                 if (inet_csk(sk)->icsk_bind_hash &&
2647                     !(sk->sk_userlocks & SOCK_BINDPORT_LOCK))
2648                         inet_put_port(sk);
2649                 fallthrough;
2650         default:
2651                 if (oldstate == TCP_ESTABLISHED)
2652                         TCP_DEC_STATS(sock_net(sk), TCP_MIB_CURRESTAB);
2653         }
2654
2655         /* Change state AFTER socket is unhashed to avoid closed
2656          * socket sitting in hash tables.
2657          */
2658         inet_sk_state_store(sk, state);
2659 }
2660 EXPORT_SYMBOL_GPL(tcp_set_state);
2661
2662 /*
2663  *      State processing on a close. This implements the state shift for
2664  *      sending our FIN frame. Note that we only send a FIN for some
2665  *      states. A shutdown() may have already sent the FIN, or we may be
2666  *      closed.
2667  */
2668
2669 static const unsigned char new_state[16] = {
2670   /* current state:        new state:      action:      */
2671   [0 /* (Invalid) */]   = TCP_CLOSE,
2672   [TCP_ESTABLISHED]     = TCP_FIN_WAIT1 | TCP_ACTION_FIN,
2673   [TCP_SYN_SENT]        = TCP_CLOSE,
2674   [TCP_SYN_RECV]        = TCP_FIN_WAIT1 | TCP_ACTION_FIN,
2675   [TCP_FIN_WAIT1]       = TCP_FIN_WAIT1,
2676   [TCP_FIN_WAIT2]       = TCP_FIN_WAIT2,
2677   [TCP_TIME_WAIT]       = TCP_CLOSE,
2678   [TCP_CLOSE]           = TCP_CLOSE,
2679   [TCP_CLOSE_WAIT]      = TCP_LAST_ACK  | TCP_ACTION_FIN,
2680   [TCP_LAST_ACK]        = TCP_LAST_ACK,
2681   [TCP_LISTEN]          = TCP_CLOSE,
2682   [TCP_CLOSING]         = TCP_CLOSING,
2683   [TCP_NEW_SYN_RECV]    = TCP_CLOSE,    /* should not happen ! */
2684 };
2685
2686 static int tcp_close_state(struct sock *sk)
2687 {
2688         int next = (int)new_state[sk->sk_state];
2689         int ns = next & TCP_STATE_MASK;
2690
2691         tcp_set_state(sk, ns);
2692
2693         return next & TCP_ACTION_FIN;
2694 }
2695
2696 /*
2697  *      Shutdown the sending side of a connection. Much like close except
2698  *      that we don't receive shut down or sock_set_flag(sk, SOCK_DEAD).
2699  */
2700
2701 void tcp_shutdown(struct sock *sk, int how)
2702 {
2703         /*      We need to grab some memory, and put together a FIN,
2704          *      and then put it into the queue to be sent.
2705          *              Tim MacKenzie(tym@dibbler.cs.monash.edu.au) 4 Dec '92.
2706          */
2707         if (!(how & SEND_SHUTDOWN))
2708                 return;
2709
2710         /* If we've already sent a FIN, or it's a closed state, skip this. */
2711         if ((1 << sk->sk_state) &
2712             (TCPF_ESTABLISHED | TCPF_SYN_SENT |
2713              TCPF_SYN_RECV | TCPF_CLOSE_WAIT)) {
2714                 /* Clear out any half completed packets.  FIN if needed. */
2715                 if (tcp_close_state(sk))
2716                         tcp_send_fin(sk);
2717         }
2718 }
2719 EXPORT_SYMBOL(tcp_shutdown);
2720
2721 int tcp_orphan_count_sum(void)
2722 {
2723         int i, total = 0;
2724
2725         for_each_possible_cpu(i)
2726                 total += per_cpu(tcp_orphan_count, i);
2727
2728         return max(total, 0);
2729 }
2730
2731 static int tcp_orphan_cache;
2732 static struct timer_list tcp_orphan_timer;
2733 #define TCP_ORPHAN_TIMER_PERIOD msecs_to_jiffies(100)
2734
2735 static void tcp_orphan_update(struct timer_list *unused)
2736 {
2737         WRITE_ONCE(tcp_orphan_cache, tcp_orphan_count_sum());
2738         mod_timer(&tcp_orphan_timer, jiffies + TCP_ORPHAN_TIMER_PERIOD);
2739 }
2740
2741 static bool tcp_too_many_orphans(int shift)
2742 {
2743         return READ_ONCE(tcp_orphan_cache) << shift >
2744                 READ_ONCE(sysctl_tcp_max_orphans);
2745 }
2746
2747 bool tcp_check_oom(struct sock *sk, int shift)
2748 {
2749         bool too_many_orphans, out_of_socket_memory;
2750
2751         too_many_orphans = tcp_too_many_orphans(shift);
2752         out_of_socket_memory = tcp_out_of_memory(sk);
2753
2754         if (too_many_orphans)
2755                 net_info_ratelimited("too many orphaned sockets\n");
2756         if (out_of_socket_memory)
2757                 net_info_ratelimited("out of memory -- consider tuning tcp_mem\n");
2758         return too_many_orphans || out_of_socket_memory;
2759 }
2760
2761 void __tcp_close(struct sock *sk, long timeout)
2762 {
2763         struct sk_buff *skb;
2764         int data_was_unread = 0;
2765         int state;
2766
2767         WRITE_ONCE(sk->sk_shutdown, SHUTDOWN_MASK);
2768
2769         if (sk->sk_state == TCP_LISTEN) {
2770                 tcp_set_state(sk, TCP_CLOSE);
2771
2772                 /* Special case. */
2773                 inet_csk_listen_stop(sk);
2774
2775                 goto adjudge_to_death;
2776         }
2777
2778         /*  We need to flush the recv. buffs.  We do this only on the
2779          *  descriptor close, not protocol-sourced closes, because the
2780          *  reader process may not have drained the data yet!
2781          */
2782         while ((skb = __skb_dequeue(&sk->sk_receive_queue)) != NULL) {
2783                 u32 len = TCP_SKB_CB(skb)->end_seq - TCP_SKB_CB(skb)->seq;
2784
2785                 if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)
2786                         len--;
2787                 data_was_unread += len;
2788                 __kfree_skb(skb);
2789         }
2790
2791         /* If socket has been already reset (e.g. in tcp_reset()) - kill it. */
2792         if (sk->sk_state == TCP_CLOSE)
2793                 goto adjudge_to_death;
2794
2795         /* As outlined in RFC 2525, section 2.17, we send a RST here because
2796          * data was lost. To witness the awful effects of the old behavior of
2797          * always doing a FIN, run an older 2.1.x kernel or 2.0.x, start a bulk
2798          * GET in an FTP client, suspend the process, wait for the client to
2799          * advertise a zero window, then kill -9 the FTP client, wheee...
2800          * Note: timeout is always zero in such a case.
2801          */
2802         if (unlikely(tcp_sk(sk)->repair)) {
2803                 sk->sk_prot->disconnect(sk, 0);
2804         } else if (data_was_unread) {
2805                 /* Unread data was tossed, zap the connection. */
2806                 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPABORTONCLOSE);
2807                 tcp_set_state(sk, TCP_CLOSE);
2808                 tcp_send_active_reset(sk, sk->sk_allocation);
2809         } else if (sock_flag(sk, SOCK_LINGER) && !sk->sk_lingertime) {
2810                 /* Check zero linger _after_ checking for unread data. */
2811                 sk->sk_prot->disconnect(sk, 0);
2812                 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPABORTONDATA);
2813         } else if (tcp_close_state(sk)) {
2814                 /* We FIN if the application ate all the data before
2815                  * zapping the connection.
2816                  */
2817
2818                 /* RED-PEN. Formally speaking, we have broken TCP state
2819                  * machine. State transitions:
2820                  *
2821                  * TCP_ESTABLISHED -> TCP_FIN_WAIT1
2822                  * TCP_SYN_RECV -> TCP_FIN_WAIT1 (forget it, it's impossible)
2823                  * TCP_CLOSE_WAIT -> TCP_LAST_ACK
2824                  *
2825                  * are legal only when FIN has been sent (i.e. in window),
2826                  * rather than queued out of window. Purists blame.
2827                  *
2828                  * F.e. "RFC state" is ESTABLISHED,
2829                  * if Linux state is FIN-WAIT-1, but FIN is still not sent.
2830                  *
2831                  * The visible declinations are that sometimes
2832                  * we enter time-wait state, when it is not required really
2833                  * (harmless), do not send active resets, when they are
2834                  * required by specs (TCP_ESTABLISHED, TCP_CLOSE_WAIT, when
2835                  * they look as CLOSING or LAST_ACK for Linux)
2836                  * Probably, I missed some more holelets.
2837                  *                                              --ANK
2838                  * XXX (TFO) - To start off we don't support SYN+ACK+FIN
2839                  * in a single packet! (May consider it later but will
2840                  * probably need API support or TCP_CORK SYN-ACK until
2841                  * data is written and socket is closed.)
2842                  */
2843                 tcp_send_fin(sk);
2844         }
2845
2846         sk_stream_wait_close(sk, timeout);
2847
2848 adjudge_to_death:
2849         state = sk->sk_state;
2850         sock_hold(sk);
2851         sock_orphan(sk);
2852
2853         local_bh_disable();
2854         bh_lock_sock(sk);
2855         /* remove backlog if any, without releasing ownership. */
2856         __release_sock(sk);
2857
2858         this_cpu_inc(tcp_orphan_count);
2859
2860         /* Have we already been destroyed by a softirq or backlog? */
2861         if (state != TCP_CLOSE && sk->sk_state == TCP_CLOSE)
2862                 goto out;
2863
2864         /*      This is a (useful) BSD violating of the RFC. There is a
2865          *      problem with TCP as specified in that the other end could
2866          *      keep a socket open forever with no application left this end.
2867          *      We use a 1 minute timeout (about the same as BSD) then kill
2868          *      our end. If they send after that then tough - BUT: long enough
2869          *      that we won't make the old 4*rto = almost no time - whoops
2870          *      reset mistake.
2871          *
2872          *      Nope, it was not mistake. It is really desired behaviour
2873          *      f.e. on http servers, when such sockets are useless, but
2874          *      consume significant resources. Let's do it with special
2875          *      linger2 option.                                 --ANK
2876          */
2877
2878         if (sk->sk_state == TCP_FIN_WAIT2) {
2879                 struct tcp_sock *tp = tcp_sk(sk);
2880                 if (READ_ONCE(tp->linger2) < 0) {
2881                         tcp_set_state(sk, TCP_CLOSE);
2882                         tcp_send_active_reset(sk, GFP_ATOMIC);
2883                         __NET_INC_STATS(sock_net(sk),
2884                                         LINUX_MIB_TCPABORTONLINGER);
2885                 } else {
2886                         const int tmo = tcp_fin_time(sk);
2887
2888                         if (tmo > TCP_TIMEWAIT_LEN) {
2889                                 inet_csk_reset_keepalive_timer(sk,
2890                                                 tmo - TCP_TIMEWAIT_LEN);
2891                         } else {
2892                                 tcp_time_wait(sk, TCP_FIN_WAIT2, tmo);
2893                                 goto out;
2894                         }
2895                 }
2896         }
2897         if (sk->sk_state != TCP_CLOSE) {
2898                 if (tcp_check_oom(sk, 0)) {
2899                         tcp_set_state(sk, TCP_CLOSE);
2900                         tcp_send_active_reset(sk, GFP_ATOMIC);
2901                         __NET_INC_STATS(sock_net(sk),
2902                                         LINUX_MIB_TCPABORTONMEMORY);
2903                 } else if (!check_net(sock_net(sk))) {
2904                         /* Not possible to send reset; just close */
2905                         tcp_set_state(sk, TCP_CLOSE);
2906                 }
2907         }
2908
2909         if (sk->sk_state == TCP_CLOSE) {
2910                 struct request_sock *req;
2911
2912                 req = rcu_dereference_protected(tcp_sk(sk)->fastopen_rsk,
2913                                                 lockdep_sock_is_held(sk));
2914                 /* We could get here with a non-NULL req if the socket is
2915                  * aborted (e.g., closed with unread data) before 3WHS
2916                  * finishes.
2917                  */
2918                 if (req)
2919                         reqsk_fastopen_remove(sk, req, false);
2920                 inet_csk_destroy_sock(sk);
2921         }
2922         /* Otherwise, socket is reprieved until protocol close. */
2923
2924 out:
2925         bh_unlock_sock(sk);
2926         local_bh_enable();
2927 }
2928
2929 void tcp_close(struct sock *sk, long timeout)
2930 {
2931         lock_sock(sk);
2932         __tcp_close(sk, timeout);
2933         release_sock(sk);
2934         sock_put(sk);
2935 }
2936 EXPORT_SYMBOL(tcp_close);
2937
2938 /* These states need RST on ABORT according to RFC793 */
2939
2940 static inline bool tcp_need_reset(int state)
2941 {
2942         return (1 << state) &
2943                (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT | TCPF_FIN_WAIT1 |
2944                 TCPF_FIN_WAIT2 | TCPF_SYN_RECV);
2945 }
2946
2947 static void tcp_rtx_queue_purge(struct sock *sk)
2948 {
2949         struct rb_node *p = rb_first(&sk->tcp_rtx_queue);
2950
2951         tcp_sk(sk)->highest_sack = NULL;
2952         while (p) {
2953                 struct sk_buff *skb = rb_to_skb(p);
2954
2955                 p = rb_next(p);
2956                 /* Since we are deleting whole queue, no need to
2957                  * list_del(&skb->tcp_tsorted_anchor)
2958                  */
2959                 tcp_rtx_queue_unlink(skb, sk);
2960                 tcp_wmem_free_skb(sk, skb);
2961         }
2962 }
2963
2964 void tcp_write_queue_purge(struct sock *sk)
2965 {
2966         struct sk_buff *skb;
2967
2968         tcp_chrono_stop(sk, TCP_CHRONO_BUSY);
2969         while ((skb = __skb_dequeue(&sk->sk_write_queue)) != NULL) {
2970                 tcp_skb_tsorted_anchor_cleanup(skb);
2971                 tcp_wmem_free_skb(sk, skb);
2972         }
2973         tcp_rtx_queue_purge(sk);
2974         INIT_LIST_HEAD(&tcp_sk(sk)->tsorted_sent_queue);
2975         tcp_clear_all_retrans_hints(tcp_sk(sk));
2976         tcp_sk(sk)->packets_out = 0;
2977         inet_csk(sk)->icsk_backoff = 0;
2978 }
2979
2980 int tcp_disconnect(struct sock *sk, int flags)
2981 {
2982         struct inet_sock *inet = inet_sk(sk);
2983         struct inet_connection_sock *icsk = inet_csk(sk);
2984         struct tcp_sock *tp = tcp_sk(sk);
2985         int old_state = sk->sk_state;
2986         u32 seq;
2987
2988         if (old_state != TCP_CLOSE)
2989                 tcp_set_state(sk, TCP_CLOSE);
2990
2991         /* ABORT function of RFC793 */
2992         if (old_state == TCP_LISTEN) {
2993                 inet_csk_listen_stop(sk);
2994         } else if (unlikely(tp->repair)) {
2995                 WRITE_ONCE(sk->sk_err, ECONNABORTED);
2996         } else if (tcp_need_reset(old_state) ||
2997                    (tp->snd_nxt != tp->write_seq &&
2998                     (1 << old_state) & (TCPF_CLOSING | TCPF_LAST_ACK))) {
2999                 /* The last check adjusts for discrepancy of Linux wrt. RFC
3000                  * states
3001                  */
3002                 tcp_send_active_reset(sk, gfp_any());
3003                 WRITE_ONCE(sk->sk_err, ECONNRESET);
3004         } else if (old_state == TCP_SYN_SENT)
3005                 WRITE_ONCE(sk->sk_err, ECONNRESET);
3006
3007         tcp_clear_xmit_timers(sk);
3008         __skb_queue_purge(&sk->sk_receive_queue);
3009         WRITE_ONCE(tp->copied_seq, tp->rcv_nxt);
3010         WRITE_ONCE(tp->urg_data, 0);
3011         tcp_write_queue_purge(sk);
3012         tcp_fastopen_active_disable_ofo_check(sk);
3013         skb_rbtree_purge(&tp->out_of_order_queue);
3014
3015         inet->inet_dport = 0;
3016
3017         inet_bhash2_reset_saddr(sk);
3018
3019         WRITE_ONCE(sk->sk_shutdown, 0);
3020         sock_reset_flag(sk, SOCK_DONE);
3021         tp->srtt_us = 0;
3022         tp->mdev_us = jiffies_to_usecs(TCP_TIMEOUT_INIT);
3023         tp->rcv_rtt_last_tsecr = 0;
3024
3025         seq = tp->write_seq + tp->max_window + 2;
3026         if (!seq)
3027                 seq = 1;
3028         WRITE_ONCE(tp->write_seq, seq);
3029
3030         icsk->icsk_backoff = 0;
3031         icsk->icsk_probes_out = 0;
3032         icsk->icsk_probes_tstamp = 0;
3033         icsk->icsk_rto = TCP_TIMEOUT_INIT;
3034         icsk->icsk_rto_min = TCP_RTO_MIN;
3035         icsk->icsk_delack_max = TCP_DELACK_MAX;
3036         tp->snd_ssthresh = TCP_INFINITE_SSTHRESH;
3037         tcp_snd_cwnd_set(tp, TCP_INIT_CWND);
3038         tp->snd_cwnd_cnt = 0;
3039         tp->is_cwnd_limited = 0;
3040         tp->max_packets_out = 0;
3041         tp->window_clamp = 0;
3042         tp->delivered = 0;
3043         tp->delivered_ce = 0;
3044         if (icsk->icsk_ca_ops->release)
3045                 icsk->icsk_ca_ops->release(sk);
3046         memset(icsk->icsk_ca_priv, 0, sizeof(icsk->icsk_ca_priv));
3047         icsk->icsk_ca_initialized = 0;
3048         tcp_set_ca_state(sk, TCP_CA_Open);
3049         tp->is_sack_reneg = 0;
3050         tcp_clear_retrans(tp);
3051         tp->total_retrans = 0;
3052         inet_csk_delack_init(sk);
3053         /* Initialize rcv_mss to TCP_MIN_MSS to avoid division by 0
3054          * issue in __tcp_select_window()
3055          */
3056         icsk->icsk_ack.rcv_mss = TCP_MIN_MSS;
3057         memset(&tp->rx_opt, 0, sizeof(tp->rx_opt));
3058         __sk_dst_reset(sk);
3059         dst_release(xchg((__force struct dst_entry **)&sk->sk_rx_dst, NULL));
3060         tcp_saved_syn_free(tp);
3061         tp->compressed_ack = 0;
3062         tp->segs_in = 0;
3063         tp->segs_out = 0;
3064         tp->bytes_sent = 0;
3065         tp->bytes_acked = 0;
3066         tp->bytes_received = 0;
3067         tp->bytes_retrans = 0;
3068         tp->data_segs_in = 0;
3069         tp->data_segs_out = 0;
3070         tp->duplicate_sack[0].start_seq = 0;
3071         tp->duplicate_sack[0].end_seq = 0;
3072         tp->dsack_dups = 0;
3073         tp->reord_seen = 0;
3074         tp->retrans_out = 0;
3075         tp->sacked_out = 0;
3076         tp->tlp_high_seq = 0;
3077         tp->last_oow_ack_time = 0;
3078         tp->plb_rehash = 0;
3079         /* There's a bubble in the pipe until at least the first ACK. */
3080         tp->app_limited = ~0U;
3081         tp->rate_app_limited = 1;
3082         tp->rack.mstamp = 0;
3083         tp->rack.advanced = 0;
3084         tp->rack.reo_wnd_steps = 1;
3085         tp->rack.last_delivered = 0;
3086         tp->rack.reo_wnd_persist = 0;
3087         tp->rack.dsack_seen = 0;
3088         tp->syn_data_acked = 0;
3089         tp->rx_opt.saw_tstamp = 0;
3090         tp->rx_opt.dsack = 0;
3091         tp->rx_opt.num_sacks = 0;
3092         tp->rcv_ooopack = 0;
3093
3094
3095         /* Clean up fastopen related fields */
3096         tcp_free_fastopen_req(tp);
3097         inet_clear_bit(DEFER_CONNECT, sk);
3098         tp->fastopen_client_fail = 0;
3099
3100         WARN_ON(inet->inet_num && !icsk->icsk_bind_hash);
3101
3102         if (sk->sk_frag.page) {
3103                 put_page(sk->sk_frag.page);
3104                 sk->sk_frag.page = NULL;
3105                 sk->sk_frag.offset = 0;
3106         }
3107         sk_error_report(sk);
3108         return 0;
3109 }
3110 EXPORT_SYMBOL(tcp_disconnect);
3111
3112 static inline bool tcp_can_repair_sock(const struct sock *sk)
3113 {
3114         return sockopt_ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN) &&
3115                 (sk->sk_state != TCP_LISTEN);
3116 }
3117
3118 static int tcp_repair_set_window(struct tcp_sock *tp, sockptr_t optbuf, int len)
3119 {
3120         struct tcp_repair_window opt;
3121
3122         if (!tp->repair)
3123                 return -EPERM;
3124
3125         if (len != sizeof(opt))
3126                 return -EINVAL;
3127
3128         if (copy_from_sockptr(&opt, optbuf, sizeof(opt)))
3129                 return -EFAULT;
3130
3131         if (opt.max_window < opt.snd_wnd)
3132                 return -EINVAL;
3133
3134         if (after(opt.snd_wl1, tp->rcv_nxt + opt.rcv_wnd))
3135                 return -EINVAL;
3136
3137         if (after(opt.rcv_wup, tp->rcv_nxt))
3138                 return -EINVAL;
3139
3140         tp->snd_wl1     = opt.snd_wl1;
3141         tp->snd_wnd     = opt.snd_wnd;
3142         tp->max_window  = opt.max_window;
3143
3144         tp->rcv_wnd     = opt.rcv_wnd;
3145         tp->rcv_wup     = opt.rcv_wup;
3146
3147         return 0;
3148 }
3149
3150 static int tcp_repair_options_est(struct sock *sk, sockptr_t optbuf,
3151                 unsigned int len)
3152 {
3153         struct tcp_sock *tp = tcp_sk(sk);
3154         struct tcp_repair_opt opt;
3155         size_t offset = 0;
3156
3157         while (len >= sizeof(opt)) {
3158                 if (copy_from_sockptr_offset(&opt, optbuf, offset, sizeof(opt)))
3159                         return -EFAULT;
3160
3161                 offset += sizeof(opt);
3162                 len -= sizeof(opt);
3163
3164                 switch (opt.opt_code) {
3165                 case TCPOPT_MSS:
3166                         tp->rx_opt.mss_clamp = opt.opt_val;
3167                         tcp_mtup_init(sk);
3168                         break;
3169                 case TCPOPT_WINDOW:
3170                         {
3171                                 u16 snd_wscale = opt.opt_val & 0xFFFF;
3172                                 u16 rcv_wscale = opt.opt_val >> 16;
3173
3174                                 if (snd_wscale > TCP_MAX_WSCALE || rcv_wscale > TCP_MAX_WSCALE)
3175                                         return -EFBIG;
3176
3177                                 tp->rx_opt.snd_wscale = snd_wscale;
3178                                 tp->rx_opt.rcv_wscale = rcv_wscale;
3179                                 tp->rx_opt.wscale_ok = 1;
3180                         }
3181                         break;
3182                 case TCPOPT_SACK_PERM:
3183                         if (opt.opt_val != 0)
3184                                 return -EINVAL;
3185
3186                         tp->rx_opt.sack_ok |= TCP_SACK_SEEN;
3187                         break;
3188                 case TCPOPT_TIMESTAMP:
3189                         if (opt.opt_val != 0)
3190                                 return -EINVAL;
3191
3192                         tp->rx_opt.tstamp_ok = 1;
3193                         break;
3194                 }
3195         }
3196
3197         return 0;
3198 }
3199
3200 DEFINE_STATIC_KEY_FALSE(tcp_tx_delay_enabled);
3201 EXPORT_SYMBOL(tcp_tx_delay_enabled);
3202
3203 static void tcp_enable_tx_delay(void)
3204 {
3205         if (!static_branch_unlikely(&tcp_tx_delay_enabled)) {
3206                 static int __tcp_tx_delay_enabled = 0;
3207
3208                 if (cmpxchg(&__tcp_tx_delay_enabled, 0, 1) == 0) {
3209                         static_branch_enable(&tcp_tx_delay_enabled);
3210                         pr_info("TCP_TX_DELAY enabled\n");
3211                 }
3212         }
3213 }
3214
3215 /* When set indicates to always queue non-full frames.  Later the user clears
3216  * this option and we transmit any pending partial frames in the queue.  This is
3217  * meant to be used alongside sendfile() to get properly filled frames when the
3218  * user (for example) must write out headers with a write() call first and then
3219  * use sendfile to send out the data parts.
3220  *
3221  * TCP_CORK can be set together with TCP_NODELAY and it is stronger than
3222  * TCP_NODELAY.
3223  */
3224 void __tcp_sock_set_cork(struct sock *sk, bool on)
3225 {
3226         struct tcp_sock *tp = tcp_sk(sk);
3227
3228         if (on) {
3229                 tp->nonagle |= TCP_NAGLE_CORK;
3230         } else {
3231                 tp->nonagle &= ~TCP_NAGLE_CORK;
3232                 if (tp->nonagle & TCP_NAGLE_OFF)
3233                         tp->nonagle |= TCP_NAGLE_PUSH;
3234                 tcp_push_pending_frames(sk);
3235         }
3236 }
3237
3238 void tcp_sock_set_cork(struct sock *sk, bool on)
3239 {
3240         lock_sock(sk);
3241         __tcp_sock_set_cork(sk, on);
3242         release_sock(sk);
3243 }
3244 EXPORT_SYMBOL(tcp_sock_set_cork);
3245
3246 /* TCP_NODELAY is weaker than TCP_CORK, so that this option on corked socket is
3247  * remembered, but it is not activated until cork is cleared.
3248  *
3249  * However, when TCP_NODELAY is set we make an explicit push, which overrides
3250  * even TCP_CORK for currently queued segments.
3251  */
3252 void __tcp_sock_set_nodelay(struct sock *sk, bool on)
3253 {
3254         if (on) {
3255                 tcp_sk(sk)->nonagle |= TCP_NAGLE_OFF|TCP_NAGLE_PUSH;
3256                 tcp_push_pending_frames(sk);
3257         } else {
3258                 tcp_sk(sk)->nonagle &= ~TCP_NAGLE_OFF;
3259         }
3260 }
3261
3262 void tcp_sock_set_nodelay(struct sock *sk)
3263 {
3264         lock_sock(sk);
3265         __tcp_sock_set_nodelay(sk, true);
3266         release_sock(sk);
3267 }
3268 EXPORT_SYMBOL(tcp_sock_set_nodelay);
3269
3270 static void __tcp_sock_set_quickack(struct sock *sk, int val)
3271 {
3272         if (!val) {
3273                 inet_csk_enter_pingpong_mode(sk);
3274                 return;
3275         }
3276
3277         inet_csk_exit_pingpong_mode(sk);
3278         if ((1 << sk->sk_state) & (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT) &&
3279             inet_csk_ack_scheduled(sk)) {
3280                 inet_csk(sk)->icsk_ack.pending |= ICSK_ACK_PUSHED;
3281                 tcp_cleanup_rbuf(sk, 1);
3282                 if (!(val & 1))
3283                         inet_csk_enter_pingpong_mode(sk);
3284         }
3285 }
3286
3287 void tcp_sock_set_quickack(struct sock *sk, int val)
3288 {
3289         lock_sock(sk);
3290         __tcp_sock_set_quickack(sk, val);
3291         release_sock(sk);
3292 }
3293 EXPORT_SYMBOL(tcp_sock_set_quickack);
3294
3295 int tcp_sock_set_syncnt(struct sock *sk, int val)
3296 {
3297         if (val < 1 || val > MAX_TCP_SYNCNT)
3298                 return -EINVAL;
3299
3300         WRITE_ONCE(inet_csk(sk)->icsk_syn_retries, val);
3301         return 0;
3302 }
3303 EXPORT_SYMBOL(tcp_sock_set_syncnt);
3304
3305 int tcp_sock_set_user_timeout(struct sock *sk, int val)
3306 {
3307         /* Cap the max time in ms TCP will retry or probe the window
3308          * before giving up and aborting (ETIMEDOUT) a connection.
3309          */
3310         if (val < 0)
3311                 return -EINVAL;
3312
3313         WRITE_ONCE(inet_csk(sk)->icsk_user_timeout, val);
3314         return 0;
3315 }
3316 EXPORT_SYMBOL(tcp_sock_set_user_timeout);
3317
3318 int tcp_sock_set_keepidle_locked(struct sock *sk, int val)
3319 {
3320         struct tcp_sock *tp = tcp_sk(sk);
3321
3322         if (val < 1 || val > MAX_TCP_KEEPIDLE)
3323                 return -EINVAL;
3324
3325         /* Paired with WRITE_ONCE() in keepalive_time_when() */
3326         WRITE_ONCE(tp->keepalive_time, val * HZ);
3327         if (sock_flag(sk, SOCK_KEEPOPEN) &&
3328             !((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN))) {
3329                 u32 elapsed = keepalive_time_elapsed(tp);
3330
3331                 if (tp->keepalive_time > elapsed)
3332                         elapsed = tp->keepalive_time - elapsed;
3333                 else
3334                         elapsed = 0;
3335                 inet_csk_reset_keepalive_timer(sk, elapsed);
3336         }
3337
3338         return 0;
3339 }
3340
3341 int tcp_sock_set_keepidle(struct sock *sk, int val)
3342 {
3343         int err;
3344
3345         lock_sock(sk);
3346         err = tcp_sock_set_keepidle_locked(sk, val);
3347         release_sock(sk);
3348         return err;
3349 }
3350 EXPORT_SYMBOL(tcp_sock_set_keepidle);
3351
3352 int tcp_sock_set_keepintvl(struct sock *sk, int val)
3353 {
3354         if (val < 1 || val > MAX_TCP_KEEPINTVL)
3355                 return -EINVAL;
3356
3357         WRITE_ONCE(tcp_sk(sk)->keepalive_intvl, val * HZ);
3358         return 0;
3359 }
3360 EXPORT_SYMBOL(tcp_sock_set_keepintvl);
3361
3362 int tcp_sock_set_keepcnt(struct sock *sk, int val)
3363 {
3364         if (val < 1 || val > MAX_TCP_KEEPCNT)
3365                 return -EINVAL;
3366
3367         /* Paired with READ_ONCE() in keepalive_probes() */
3368         WRITE_ONCE(tcp_sk(sk)->keepalive_probes, val);
3369         return 0;
3370 }
3371 EXPORT_SYMBOL(tcp_sock_set_keepcnt);
3372
3373 int tcp_set_window_clamp(struct sock *sk, int val)
3374 {
3375         struct tcp_sock *tp = tcp_sk(sk);
3376
3377         if (!val) {
3378                 if (sk->sk_state != TCP_CLOSE)
3379                         return -EINVAL;
3380                 tp->window_clamp = 0;
3381         } else {
3382                 u32 new_rcv_ssthresh, old_window_clamp = tp->window_clamp;
3383                 u32 new_window_clamp = val < SOCK_MIN_RCVBUF / 2 ?
3384                                                 SOCK_MIN_RCVBUF / 2 : val;
3385
3386                 if (new_window_clamp == old_window_clamp)
3387                         return 0;
3388
3389                 tp->window_clamp = new_window_clamp;
3390                 if (new_window_clamp < old_window_clamp) {
3391                         /* need to apply the reserved mem provisioning only
3392                          * when shrinking the window clamp
3393                          */
3394                         __tcp_adjust_rcv_ssthresh(sk, tp->window_clamp);
3395
3396                 } else {
3397                         new_rcv_ssthresh = min(tp->rcv_wnd, tp->window_clamp);
3398                         tp->rcv_ssthresh = max(new_rcv_ssthresh,
3399                                                tp->rcv_ssthresh);
3400                 }
3401         }
3402         return 0;
3403 }
3404
3405 /*
3406  *      Socket option code for TCP.
3407  */
3408 int do_tcp_setsockopt(struct sock *sk, int level, int optname,
3409                       sockptr_t optval, unsigned int optlen)
3410 {
3411         struct tcp_sock *tp = tcp_sk(sk);
3412         struct inet_connection_sock *icsk = inet_csk(sk);
3413         struct net *net = sock_net(sk);
3414         int val;
3415         int err = 0;
3416
3417         /* These are data/string values, all the others are ints */
3418         switch (optname) {
3419         case TCP_CONGESTION: {
3420                 char name[TCP_CA_NAME_MAX];
3421
3422                 if (optlen < 1)
3423                         return -EINVAL;
3424
3425                 val = strncpy_from_sockptr(name, optval,
3426                                         min_t(long, TCP_CA_NAME_MAX-1, optlen));
3427                 if (val < 0)
3428                         return -EFAULT;
3429                 name[val] = 0;
3430
3431                 sockopt_lock_sock(sk);
3432                 err = tcp_set_congestion_control(sk, name, !has_current_bpf_ctx(),
3433                                                  sockopt_ns_capable(sock_net(sk)->user_ns,
3434                                                                     CAP_NET_ADMIN));
3435                 sockopt_release_sock(sk);
3436                 return err;
3437         }
3438         case TCP_ULP: {
3439                 char name[TCP_ULP_NAME_MAX];
3440
3441                 if (optlen < 1)
3442                         return -EINVAL;
3443
3444                 val = strncpy_from_sockptr(name, optval,
3445                                         min_t(long, TCP_ULP_NAME_MAX - 1,
3446                                               optlen));
3447                 if (val < 0)
3448                         return -EFAULT;
3449                 name[val] = 0;
3450
3451                 sockopt_lock_sock(sk);
3452                 err = tcp_set_ulp(sk, name);
3453                 sockopt_release_sock(sk);
3454                 return err;
3455         }
3456         case TCP_FASTOPEN_KEY: {
3457                 __u8 key[TCP_FASTOPEN_KEY_BUF_LENGTH];
3458                 __u8 *backup_key = NULL;
3459
3460                 /* Allow a backup key as well to facilitate key rotation
3461                  * First key is the active one.
3462                  */
3463                 if (optlen != TCP_FASTOPEN_KEY_LENGTH &&
3464                     optlen != TCP_FASTOPEN_KEY_BUF_LENGTH)
3465                         return -EINVAL;
3466
3467                 if (copy_from_sockptr(key, optval, optlen))
3468                         return -EFAULT;
3469
3470                 if (optlen == TCP_FASTOPEN_KEY_BUF_LENGTH)
3471                         backup_key = key + TCP_FASTOPEN_KEY_LENGTH;
3472
3473                 return tcp_fastopen_reset_cipher(net, sk, key, backup_key);
3474         }
3475         default:
3476                 /* fallthru */
3477                 break;
3478         }
3479
3480         if (optlen < sizeof(int))
3481                 return -EINVAL;
3482
3483         if (copy_from_sockptr(&val, optval, sizeof(val)))
3484                 return -EFAULT;
3485
3486         /* Handle options that can be set without locking the socket. */
3487         switch (optname) {
3488         case TCP_SYNCNT:
3489                 return tcp_sock_set_syncnt(sk, val);
3490         case TCP_USER_TIMEOUT:
3491                 return tcp_sock_set_user_timeout(sk, val);
3492         case TCP_KEEPINTVL:
3493                 return tcp_sock_set_keepintvl(sk, val);
3494         case TCP_KEEPCNT:
3495                 return tcp_sock_set_keepcnt(sk, val);
3496         case TCP_LINGER2:
3497                 if (val < 0)
3498                         WRITE_ONCE(tp->linger2, -1);
3499                 else if (val > TCP_FIN_TIMEOUT_MAX / HZ)
3500                         WRITE_ONCE(tp->linger2, TCP_FIN_TIMEOUT_MAX);
3501                 else
3502                         WRITE_ONCE(tp->linger2, val * HZ);
3503                 return 0;
3504         case TCP_DEFER_ACCEPT:
3505                 /* Translate value in seconds to number of retransmits */
3506                 WRITE_ONCE(icsk->icsk_accept_queue.rskq_defer_accept,
3507                            secs_to_retrans(val, TCP_TIMEOUT_INIT / HZ,
3508                                            TCP_RTO_MAX / HZ));
3509                 return 0;
3510         }
3511
3512         sockopt_lock_sock(sk);
3513
3514         switch (optname) {
3515         case TCP_MAXSEG:
3516                 /* Values greater than interface MTU won't take effect. However
3517                  * at the point when this call is done we typically don't yet
3518                  * know which interface is going to be used
3519                  */
3520                 if (val && (val < TCP_MIN_MSS || val > MAX_TCP_WINDOW)) {
3521                         err = -EINVAL;
3522                         break;
3523                 }
3524                 tp->rx_opt.user_mss = val;
3525                 break;
3526
3527         case TCP_NODELAY:
3528                 __tcp_sock_set_nodelay(sk, val);
3529                 break;
3530
3531         case TCP_THIN_LINEAR_TIMEOUTS:
3532                 if (val < 0 || val > 1)
3533                         err = -EINVAL;
3534                 else
3535                         tp->thin_lto = val;
3536                 break;
3537
3538         case TCP_THIN_DUPACK:
3539                 if (val < 0 || val > 1)
3540                         err = -EINVAL;
3541                 break;
3542
3543         case TCP_REPAIR:
3544                 if (!tcp_can_repair_sock(sk))
3545                         err = -EPERM;
3546                 else if (val == TCP_REPAIR_ON) {
3547                         tp->repair = 1;
3548                         sk->sk_reuse = SK_FORCE_REUSE;
3549                         tp->repair_queue = TCP_NO_QUEUE;
3550                 } else if (val == TCP_REPAIR_OFF) {
3551                         tp->repair = 0;
3552                         sk->sk_reuse = SK_NO_REUSE;
3553                         tcp_send_window_probe(sk);
3554                 } else if (val == TCP_REPAIR_OFF_NO_WP) {
3555                         tp->repair = 0;
3556                         sk->sk_reuse = SK_NO_REUSE;
3557                 } else
3558                         err = -EINVAL;
3559
3560                 break;
3561
3562         case TCP_REPAIR_QUEUE:
3563                 if (!tp->repair)
3564                         err = -EPERM;
3565                 else if ((unsigned int)val < TCP_QUEUES_NR)
3566                         tp->repair_queue = val;
3567                 else
3568                         err = -EINVAL;
3569                 break;
3570
3571         case TCP_QUEUE_SEQ:
3572                 if (sk->sk_state != TCP_CLOSE) {
3573                         err = -EPERM;
3574                 } else if (tp->repair_queue == TCP_SEND_QUEUE) {
3575                         if (!tcp_rtx_queue_empty(sk))
3576                                 err = -EPERM;
3577                         else
3578                                 WRITE_ONCE(tp->write_seq, val);
3579                 } else if (tp->repair_queue == TCP_RECV_QUEUE) {
3580                         if (tp->rcv_nxt != tp->copied_seq) {
3581                                 err = -EPERM;
3582                         } else {
3583                                 WRITE_ONCE(tp->rcv_nxt, val);
3584                                 WRITE_ONCE(tp->copied_seq, val);
3585                         }
3586                 } else {
3587                         err = -EINVAL;
3588                 }
3589                 break;
3590
3591         case TCP_REPAIR_OPTIONS:
3592                 if (!tp->repair)
3593                         err = -EINVAL;
3594                 else if (sk->sk_state == TCP_ESTABLISHED && !tp->bytes_sent)
3595                         err = tcp_repair_options_est(sk, optval, optlen);
3596                 else
3597                         err = -EPERM;
3598                 break;
3599
3600         case TCP_CORK:
3601                 __tcp_sock_set_cork(sk, val);
3602                 break;
3603
3604         case TCP_KEEPIDLE:
3605                 err = tcp_sock_set_keepidle_locked(sk, val);
3606                 break;
3607         case TCP_SAVE_SYN:
3608                 /* 0: disable, 1: enable, 2: start from ether_header */
3609                 if (val < 0 || val > 2)
3610                         err = -EINVAL;
3611                 else
3612                         tp->save_syn = val;
3613                 break;
3614
3615         case TCP_WINDOW_CLAMP:
3616                 err = tcp_set_window_clamp(sk, val);
3617                 break;
3618
3619         case TCP_QUICKACK:
3620                 __tcp_sock_set_quickack(sk, val);
3621                 break;
3622
3623         case TCP_AO_REPAIR:
3624                 if (!tcp_can_repair_sock(sk)) {
3625                         err = -EPERM;
3626                         break;
3627                 }
3628                 err = tcp_ao_set_repair(sk, optval, optlen);
3629                 break;
3630 #ifdef CONFIG_TCP_AO
3631         case TCP_AO_ADD_KEY:
3632         case TCP_AO_DEL_KEY:
3633         case TCP_AO_INFO: {
3634                 /* If this is the first TCP-AO setsockopt() on the socket,
3635                  * sk_state has to be LISTEN or CLOSE. Allow TCP_REPAIR
3636                  * in any state.
3637                  */
3638                 if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE))
3639                         goto ao_parse;
3640                 if (rcu_dereference_protected(tcp_sk(sk)->ao_info,
3641                                               lockdep_sock_is_held(sk)))
3642                         goto ao_parse;
3643                 if (tp->repair)
3644                         goto ao_parse;
3645                 err = -EISCONN;
3646                 break;
3647 ao_parse:
3648                 err = tp->af_specific->ao_parse(sk, optname, optval, optlen);
3649                 break;
3650         }
3651 #endif
3652 #ifdef CONFIG_TCP_MD5SIG
3653         case TCP_MD5SIG:
3654         case TCP_MD5SIG_EXT:
3655                 err = tp->af_specific->md5_parse(sk, optname, optval, optlen);
3656                 break;
3657 #endif
3658         case TCP_FASTOPEN:
3659                 if (val >= 0 && ((1 << sk->sk_state) & (TCPF_CLOSE |
3660                     TCPF_LISTEN))) {
3661                         tcp_fastopen_init_key_once(net);
3662
3663                         fastopen_queue_tune(sk, val);
3664                 } else {
3665                         err = -EINVAL;
3666                 }
3667                 break;
3668         case TCP_FASTOPEN_CONNECT:
3669                 if (val > 1 || val < 0) {
3670                         err = -EINVAL;
3671                 } else if (READ_ONCE(net->ipv4.sysctl_tcp_fastopen) &
3672                            TFO_CLIENT_ENABLE) {
3673                         if (sk->sk_state == TCP_CLOSE)
3674                                 tp->fastopen_connect = val;
3675                         else
3676                                 err = -EINVAL;
3677                 } else {
3678                         err = -EOPNOTSUPP;
3679                 }
3680                 break;
3681         case TCP_FASTOPEN_NO_COOKIE:
3682                 if (val > 1 || val < 0)
3683                         err = -EINVAL;
3684                 else if (!((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN)))
3685                         err = -EINVAL;
3686                 else
3687                         tp->fastopen_no_cookie = val;
3688                 break;
3689         case TCP_TIMESTAMP:
3690                 if (!tp->repair) {
3691                         err = -EPERM;
3692                         break;
3693                 }
3694                 /* val is an opaque field,
3695                  * and low order bit contains usec_ts enable bit.
3696                  * Its a best effort, and we do not care if user makes an error.
3697                  */
3698                 tp->tcp_usec_ts = val & 1;
3699                 WRITE_ONCE(tp->tsoffset, val - tcp_clock_ts(tp->tcp_usec_ts));
3700                 break;
3701         case TCP_REPAIR_WINDOW:
3702                 err = tcp_repair_set_window(tp, optval, optlen);
3703                 break;
3704         case TCP_NOTSENT_LOWAT:
3705                 WRITE_ONCE(tp->notsent_lowat, val);
3706                 sk->sk_write_space(sk);
3707                 break;
3708         case TCP_INQ:
3709                 if (val > 1 || val < 0)
3710                         err = -EINVAL;
3711                 else
3712                         tp->recvmsg_inq = val;
3713                 break;
3714         case TCP_TX_DELAY:
3715                 if (val)
3716                         tcp_enable_tx_delay();
3717                 WRITE_ONCE(tp->tcp_tx_delay, val);
3718                 break;
3719         default:
3720                 err = -ENOPROTOOPT;
3721                 break;
3722         }
3723
3724         sockopt_release_sock(sk);
3725         return err;
3726 }
3727
3728 int tcp_setsockopt(struct sock *sk, int level, int optname, sockptr_t optval,
3729                    unsigned int optlen)
3730 {
3731         const struct inet_connection_sock *icsk = inet_csk(sk);
3732
3733         if (level != SOL_TCP)
3734                 /* Paired with WRITE_ONCE() in do_ipv6_setsockopt() and tcp_v6_connect() */
3735                 return READ_ONCE(icsk->icsk_af_ops)->setsockopt(sk, level, optname,
3736                                                                 optval, optlen);
3737         return do_tcp_setsockopt(sk, level, optname, optval, optlen);
3738 }
3739 EXPORT_SYMBOL(tcp_setsockopt);
3740
3741 static void tcp_get_info_chrono_stats(const struct tcp_sock *tp,
3742                                       struct tcp_info *info)
3743 {
3744         u64 stats[__TCP_CHRONO_MAX], total = 0;
3745         enum tcp_chrono i;
3746
3747         for (i = TCP_CHRONO_BUSY; i < __TCP_CHRONO_MAX; ++i) {
3748                 stats[i] = tp->chrono_stat[i - 1];
3749                 if (i == tp->chrono_type)
3750                         stats[i] += tcp_jiffies32 - tp->chrono_start;
3751                 stats[i] *= USEC_PER_SEC / HZ;
3752                 total += stats[i];
3753         }
3754
3755         info->tcpi_busy_time = total;
3756         info->tcpi_rwnd_limited = stats[TCP_CHRONO_RWND_LIMITED];
3757         info->tcpi_sndbuf_limited = stats[TCP_CHRONO_SNDBUF_LIMITED];
3758 }
3759
3760 /* Return information about state of tcp endpoint in API format. */
3761 void tcp_get_info(struct sock *sk, struct tcp_info *info)
3762 {
3763         const struct tcp_sock *tp = tcp_sk(sk); /* iff sk_type == SOCK_STREAM */
3764         const struct inet_connection_sock *icsk = inet_csk(sk);
3765         unsigned long rate;
3766         u32 now;
3767         u64 rate64;
3768         bool slow;
3769
3770         memset(info, 0, sizeof(*info));
3771         if (sk->sk_type != SOCK_STREAM)
3772                 return;
3773
3774         info->tcpi_state = inet_sk_state_load(sk);
3775
3776         /* Report meaningful fields for all TCP states, including listeners */
3777         rate = READ_ONCE(sk->sk_pacing_rate);
3778         rate64 = (rate != ~0UL) ? rate : ~0ULL;
3779         info->tcpi_pacing_rate = rate64;
3780
3781         rate = READ_ONCE(sk->sk_max_pacing_rate);
3782         rate64 = (rate != ~0UL) ? rate : ~0ULL;
3783         info->tcpi_max_pacing_rate = rate64;
3784
3785         info->tcpi_reordering = tp->reordering;
3786         info->tcpi_snd_cwnd = tcp_snd_cwnd(tp);
3787
3788         if (info->tcpi_state == TCP_LISTEN) {
3789                 /* listeners aliased fields :
3790                  * tcpi_unacked -> Number of children ready for accept()
3791                  * tcpi_sacked  -> max backlog
3792                  */
3793                 info->tcpi_unacked = READ_ONCE(sk->sk_ack_backlog);
3794                 info->tcpi_sacked = READ_ONCE(sk->sk_max_ack_backlog);
3795                 return;
3796         }
3797
3798         slow = lock_sock_fast(sk);
3799
3800         info->tcpi_ca_state = icsk->icsk_ca_state;
3801         info->tcpi_retransmits = icsk->icsk_retransmits;
3802         info->tcpi_probes = icsk->icsk_probes_out;
3803         info->tcpi_backoff = icsk->icsk_backoff;
3804
3805         if (tp->rx_opt.tstamp_ok)
3806                 info->tcpi_options |= TCPI_OPT_TIMESTAMPS;
3807         if (tcp_is_sack(tp))
3808                 info->tcpi_options |= TCPI_OPT_SACK;
3809         if (tp->rx_opt.wscale_ok) {
3810                 info->tcpi_options |= TCPI_OPT_WSCALE;
3811                 info->tcpi_snd_wscale = tp->rx_opt.snd_wscale;
3812                 info->tcpi_rcv_wscale = tp->rx_opt.rcv_wscale;
3813         }
3814
3815         if (tp->ecn_flags & TCP_ECN_OK)
3816                 info->tcpi_options |= TCPI_OPT_ECN;
3817         if (tp->ecn_flags & TCP_ECN_SEEN)
3818                 info->tcpi_options |= TCPI_OPT_ECN_SEEN;
3819         if (tp->syn_data_acked)
3820                 info->tcpi_options |= TCPI_OPT_SYN_DATA;
3821         if (tp->tcp_usec_ts)
3822                 info->tcpi_options |= TCPI_OPT_USEC_TS;
3823
3824         info->tcpi_rto = jiffies_to_usecs(icsk->icsk_rto);
3825         info->tcpi_ato = jiffies_to_usecs(min_t(u32, icsk->icsk_ack.ato,
3826                                                 tcp_delack_max(sk)));
3827         info->tcpi_snd_mss = tp->mss_cache;
3828         info->tcpi_rcv_mss = icsk->icsk_ack.rcv_mss;
3829
3830         info->tcpi_unacked = tp->packets_out;
3831         info->tcpi_sacked = tp->sacked_out;
3832
3833         info->tcpi_lost = tp->lost_out;
3834         info->tcpi_retrans = tp->retrans_out;
3835
3836         now = tcp_jiffies32;
3837         info->tcpi_last_data_sent = jiffies_to_msecs(now - tp->lsndtime);
3838         info->tcpi_last_data_recv = jiffies_to_msecs(now - icsk->icsk_ack.lrcvtime);
3839         info->tcpi_last_ack_recv = jiffies_to_msecs(now - tp->rcv_tstamp);
3840
3841         info->tcpi_pmtu = icsk->icsk_pmtu_cookie;
3842         info->tcpi_rcv_ssthresh = tp->rcv_ssthresh;
3843         info->tcpi_rtt = tp->srtt_us >> 3;
3844         info->tcpi_rttvar = tp->mdev_us >> 2;
3845         info->tcpi_snd_ssthresh = tp->snd_ssthresh;
3846         info->tcpi_advmss = tp->advmss;
3847
3848         info->tcpi_rcv_rtt = tp->rcv_rtt_est.rtt_us >> 3;
3849         info->tcpi_rcv_space = tp->rcvq_space.space;
3850
3851         info->tcpi_total_retrans = tp->total_retrans;
3852
3853         info->tcpi_bytes_acked = tp->bytes_acked;
3854         info->tcpi_bytes_received = tp->bytes_received;
3855         info->tcpi_notsent_bytes = max_t(int, 0, tp->write_seq - tp->snd_nxt);
3856         tcp_get_info_chrono_stats(tp, info);
3857
3858         info->tcpi_segs_out = tp->segs_out;
3859
3860         /* segs_in and data_segs_in can be updated from tcp_segs_in() from BH */
3861         info->tcpi_segs_in = READ_ONCE(tp->segs_in);
3862         info->tcpi_data_segs_in = READ_ONCE(tp->data_segs_in);
3863
3864         info->tcpi_min_rtt = tcp_min_rtt(tp);
3865         info->tcpi_data_segs_out = tp->data_segs_out;
3866
3867         info->tcpi_delivery_rate_app_limited = tp->rate_app_limited ? 1 : 0;
3868         rate64 = tcp_compute_delivery_rate(tp);
3869         if (rate64)
3870                 info->tcpi_delivery_rate = rate64;
3871         info->tcpi_delivered = tp->delivered;
3872         info->tcpi_delivered_ce = tp->delivered_ce;
3873         info->tcpi_bytes_sent = tp->bytes_sent;
3874         info->tcpi_bytes_retrans = tp->bytes_retrans;
3875         info->tcpi_dsack_dups = tp->dsack_dups;
3876         info->tcpi_reord_seen = tp->reord_seen;
3877         info->tcpi_rcv_ooopack = tp->rcv_ooopack;
3878         info->tcpi_snd_wnd = tp->snd_wnd;
3879         info->tcpi_rcv_wnd = tp->rcv_wnd;
3880         info->tcpi_rehash = tp->plb_rehash + tp->timeout_rehash;
3881         info->tcpi_fastopen_client_fail = tp->fastopen_client_fail;
3882
3883         info->tcpi_total_rto = tp->total_rto;
3884         info->tcpi_total_rto_recoveries = tp->total_rto_recoveries;
3885         info->tcpi_total_rto_time = tp->total_rto_time;
3886         if (tp->rto_stamp)
3887                 info->tcpi_total_rto_time += tcp_clock_ms() - tp->rto_stamp;
3888
3889         unlock_sock_fast(sk, slow);
3890 }
3891 EXPORT_SYMBOL_GPL(tcp_get_info);
3892
3893 static size_t tcp_opt_stats_get_size(void)
3894 {
3895         return
3896                 nla_total_size_64bit(sizeof(u64)) + /* TCP_NLA_BUSY */
3897                 nla_total_size_64bit(sizeof(u64)) + /* TCP_NLA_RWND_LIMITED */
3898                 nla_total_size_64bit(sizeof(u64)) + /* TCP_NLA_SNDBUF_LIMITED */
3899                 nla_total_size_64bit(sizeof(u64)) + /* TCP_NLA_DATA_SEGS_OUT */
3900                 nla_total_size_64bit(sizeof(u64)) + /* TCP_NLA_TOTAL_RETRANS */
3901                 nla_total_size_64bit(sizeof(u64)) + /* TCP_NLA_PACING_RATE */
3902                 nla_total_size_64bit(sizeof(u64)) + /* TCP_NLA_DELIVERY_RATE */
3903                 nla_total_size(sizeof(u32)) + /* TCP_NLA_SND_CWND */
3904                 nla_total_size(sizeof(u32)) + /* TCP_NLA_REORDERING */
3905                 nla_total_size(sizeof(u32)) + /* TCP_NLA_MIN_RTT */
3906                 nla_total_size(sizeof(u8)) + /* TCP_NLA_RECUR_RETRANS */
3907                 nla_total_size(sizeof(u8)) + /* TCP_NLA_DELIVERY_RATE_APP_LMT */
3908                 nla_total_size(sizeof(u32)) + /* TCP_NLA_SNDQ_SIZE */
3909                 nla_total_size(sizeof(u8)) + /* TCP_NLA_CA_STATE */
3910                 nla_total_size(sizeof(u32)) + /* TCP_NLA_SND_SSTHRESH */
3911                 nla_total_size(sizeof(u32)) + /* TCP_NLA_DELIVERED */
3912                 nla_total_size(sizeof(u32)) + /* TCP_NLA_DELIVERED_CE */
3913                 nla_total_size_64bit(sizeof(u64)) + /* TCP_NLA_BYTES_SENT */
3914                 nla_total_size_64bit(sizeof(u64)) + /* TCP_NLA_BYTES_RETRANS */
3915                 nla_total_size(sizeof(u32)) + /* TCP_NLA_DSACK_DUPS */
3916                 nla_total_size(sizeof(u32)) + /* TCP_NLA_REORD_SEEN */
3917                 nla_total_size(sizeof(u32)) + /* TCP_NLA_SRTT */
3918                 nla_total_size(sizeof(u16)) + /* TCP_NLA_TIMEOUT_REHASH */
3919                 nla_total_size(sizeof(u32)) + /* TCP_NLA_BYTES_NOTSENT */
3920                 nla_total_size_64bit(sizeof(u64)) + /* TCP_NLA_EDT */
3921                 nla_total_size(sizeof(u8)) + /* TCP_NLA_TTL */
3922                 nla_total_size(sizeof(u32)) + /* TCP_NLA_REHASH */
3923                 0;
3924 }
3925
3926 /* Returns TTL or hop limit of an incoming packet from skb. */
3927 static u8 tcp_skb_ttl_or_hop_limit(const struct sk_buff *skb)
3928 {
3929         if (skb->protocol == htons(ETH_P_IP))
3930                 return ip_hdr(skb)->ttl;
3931         else if (skb->protocol == htons(ETH_P_IPV6))
3932                 return ipv6_hdr(skb)->hop_limit;
3933         else
3934                 return 0;
3935 }
3936
3937 struct sk_buff *tcp_get_timestamping_opt_stats(const struct sock *sk,
3938                                                const struct sk_buff *orig_skb,
3939                                                const struct sk_buff *ack_skb)
3940 {
3941         const struct tcp_sock *tp = tcp_sk(sk);
3942         struct sk_buff *stats;
3943         struct tcp_info info;
3944         unsigned long rate;
3945         u64 rate64;
3946
3947         stats = alloc_skb(tcp_opt_stats_get_size(), GFP_ATOMIC);
3948         if (!stats)
3949                 return NULL;
3950
3951         tcp_get_info_chrono_stats(tp, &info);
3952         nla_put_u64_64bit(stats, TCP_NLA_BUSY,
3953                           info.tcpi_busy_time, TCP_NLA_PAD);
3954         nla_put_u64_64bit(stats, TCP_NLA_RWND_LIMITED,
3955                           info.tcpi_rwnd_limited, TCP_NLA_PAD);
3956         nla_put_u64_64bit(stats, TCP_NLA_SNDBUF_LIMITED,
3957                           info.tcpi_sndbuf_limited, TCP_NLA_PAD);
3958         nla_put_u64_64bit(stats, TCP_NLA_DATA_SEGS_OUT,
3959                           tp->data_segs_out, TCP_NLA_PAD);
3960         nla_put_u64_64bit(stats, TCP_NLA_TOTAL_RETRANS,
3961                           tp->total_retrans, TCP_NLA_PAD);
3962
3963         rate = READ_ONCE(sk->sk_pacing_rate);
3964         rate64 = (rate != ~0UL) ? rate : ~0ULL;
3965         nla_put_u64_64bit(stats, TCP_NLA_PACING_RATE, rate64, TCP_NLA_PAD);
3966
3967         rate64 = tcp_compute_delivery_rate(tp);
3968         nla_put_u64_64bit(stats, TCP_NLA_DELIVERY_RATE, rate64, TCP_NLA_PAD);
3969
3970         nla_put_u32(stats, TCP_NLA_SND_CWND, tcp_snd_cwnd(tp));
3971         nla_put_u32(stats, TCP_NLA_REORDERING, tp->reordering);
3972         nla_put_u32(stats, TCP_NLA_MIN_RTT, tcp_min_rtt(tp));
3973
3974         nla_put_u8(stats, TCP_NLA_RECUR_RETRANS, inet_csk(sk)->icsk_retransmits);
3975         nla_put_u8(stats, TCP_NLA_DELIVERY_RATE_APP_LMT, !!tp->rate_app_limited);
3976         nla_put_u32(stats, TCP_NLA_SND_SSTHRESH, tp->snd_ssthresh);
3977         nla_put_u32(stats, TCP_NLA_DELIVERED, tp->delivered);
3978         nla_put_u32(stats, TCP_NLA_DELIVERED_CE, tp->delivered_ce);
3979
3980         nla_put_u32(stats, TCP_NLA_SNDQ_SIZE, tp->write_seq - tp->snd_una);
3981         nla_put_u8(stats, TCP_NLA_CA_STATE, inet_csk(sk)->icsk_ca_state);
3982
3983         nla_put_u64_64bit(stats, TCP_NLA_BYTES_SENT, tp->bytes_sent,
3984                           TCP_NLA_PAD);
3985         nla_put_u64_64bit(stats, TCP_NLA_BYTES_RETRANS, tp->bytes_retrans,
3986                           TCP_NLA_PAD);
3987         nla_put_u32(stats, TCP_NLA_DSACK_DUPS, tp->dsack_dups);
3988         nla_put_u32(stats, TCP_NLA_REORD_SEEN, tp->reord_seen);
3989         nla_put_u32(stats, TCP_NLA_SRTT, tp->srtt_us >> 3);
3990         nla_put_u16(stats, TCP_NLA_TIMEOUT_REHASH, tp->timeout_rehash);
3991         nla_put_u32(stats, TCP_NLA_BYTES_NOTSENT,
3992                     max_t(int, 0, tp->write_seq - tp->snd_nxt));
3993         nla_put_u64_64bit(stats, TCP_NLA_EDT, orig_skb->skb_mstamp_ns,
3994                           TCP_NLA_PAD);
3995         if (ack_skb)
3996                 nla_put_u8(stats, TCP_NLA_TTL,
3997                            tcp_skb_ttl_or_hop_limit(ack_skb));
3998
3999         nla_put_u32(stats, TCP_NLA_REHASH, tp->plb_rehash + tp->timeout_rehash);
4000         return stats;
4001 }
4002
4003 int do_tcp_getsockopt(struct sock *sk, int level,
4004                       int optname, sockptr_t optval, sockptr_t optlen)
4005 {
4006         struct inet_connection_sock *icsk = inet_csk(sk);
4007         struct tcp_sock *tp = tcp_sk(sk);
4008         struct net *net = sock_net(sk);
4009         int val, len;
4010
4011         if (copy_from_sockptr(&len, optlen, sizeof(int)))
4012                 return -EFAULT;
4013
4014         if (len < 0)
4015                 return -EINVAL;
4016
4017         len = min_t(unsigned int, len, sizeof(int));
4018
4019         switch (optname) {
4020         case TCP_MAXSEG:
4021                 val = tp->mss_cache;
4022                 if (tp->rx_opt.user_mss &&
4023                     ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN)))
4024                         val = tp->rx_opt.user_mss;
4025                 if (tp->repair)
4026                         val = tp->rx_opt.mss_clamp;
4027                 break;
4028         case TCP_NODELAY:
4029                 val = !!(tp->nonagle&TCP_NAGLE_OFF);
4030                 break;
4031         case TCP_CORK:
4032                 val = !!(tp->nonagle&TCP_NAGLE_CORK);
4033                 break;
4034         case TCP_KEEPIDLE:
4035                 val = keepalive_time_when(tp) / HZ;
4036                 break;
4037         case TCP_KEEPINTVL:
4038                 val = keepalive_intvl_when(tp) / HZ;
4039                 break;
4040         case TCP_KEEPCNT:
4041                 val = keepalive_probes(tp);
4042                 break;
4043         case TCP_SYNCNT:
4044                 val = READ_ONCE(icsk->icsk_syn_retries) ? :
4045                         READ_ONCE(net->ipv4.sysctl_tcp_syn_retries);
4046                 break;
4047         case TCP_LINGER2:
4048                 val = READ_ONCE(tp->linger2);
4049                 if (val >= 0)
4050                         val = (val ? : READ_ONCE(net->ipv4.sysctl_tcp_fin_timeout)) / HZ;
4051                 break;
4052         case TCP_DEFER_ACCEPT:
4053                 val = READ_ONCE(icsk->icsk_accept_queue.rskq_defer_accept);
4054                 val = retrans_to_secs(val, TCP_TIMEOUT_INIT / HZ,
4055                                       TCP_RTO_MAX / HZ);
4056                 break;
4057         case TCP_WINDOW_CLAMP:
4058                 val = tp->window_clamp;
4059                 break;
4060         case TCP_INFO: {
4061                 struct tcp_info info;
4062
4063                 if (copy_from_sockptr(&len, optlen, sizeof(int)))
4064                         return -EFAULT;
4065
4066                 tcp_get_info(sk, &info);
4067
4068                 len = min_t(unsigned int, len, sizeof(info));
4069                 if (copy_to_sockptr(optlen, &len, sizeof(int)))
4070                         return -EFAULT;
4071                 if (copy_to_sockptr(optval, &info, len))
4072                         return -EFAULT;
4073                 return 0;
4074         }
4075         case TCP_CC_INFO: {
4076                 const struct tcp_congestion_ops *ca_ops;
4077                 union tcp_cc_info info;
4078                 size_t sz = 0;
4079                 int attr;
4080
4081                 if (copy_from_sockptr(&len, optlen, sizeof(int)))
4082                         return -EFAULT;
4083
4084                 ca_ops = icsk->icsk_ca_ops;
4085                 if (ca_ops && ca_ops->get_info)
4086                         sz = ca_ops->get_info(sk, ~0U, &attr, &info);
4087
4088                 len = min_t(unsigned int, len, sz);
4089                 if (copy_to_sockptr(optlen, &len, sizeof(int)))
4090                         return -EFAULT;
4091                 if (copy_to_sockptr(optval, &info, len))
4092                         return -EFAULT;
4093                 return 0;
4094         }
4095         case TCP_QUICKACK:
4096                 val = !inet_csk_in_pingpong_mode(sk);
4097                 break;
4098
4099         case TCP_CONGESTION:
4100                 if (copy_from_sockptr(&len, optlen, sizeof(int)))
4101                         return -EFAULT;
4102                 len = min_t(unsigned int, len, TCP_CA_NAME_MAX);
4103                 if (copy_to_sockptr(optlen, &len, sizeof(int)))
4104                         return -EFAULT;
4105                 if (copy_to_sockptr(optval, icsk->icsk_ca_ops->name, len))
4106                         return -EFAULT;
4107                 return 0;
4108
4109         case TCP_ULP:
4110                 if (copy_from_sockptr(&len, optlen, sizeof(int)))
4111                         return -EFAULT;
4112                 len = min_t(unsigned int, len, TCP_ULP_NAME_MAX);
4113                 if (!icsk->icsk_ulp_ops) {
4114                         len = 0;
4115                         if (copy_to_sockptr(optlen, &len, sizeof(int)))
4116                                 return -EFAULT;
4117                         return 0;
4118                 }
4119                 if (copy_to_sockptr(optlen, &len, sizeof(int)))
4120                         return -EFAULT;
4121                 if (copy_to_sockptr(optval, icsk->icsk_ulp_ops->name, len))
4122                         return -EFAULT;
4123                 return 0;
4124
4125         case TCP_FASTOPEN_KEY: {
4126                 u64 key[TCP_FASTOPEN_KEY_BUF_LENGTH / sizeof(u64)];
4127                 unsigned int key_len;
4128
4129                 if (copy_from_sockptr(&len, optlen, sizeof(int)))
4130                         return -EFAULT;
4131
4132                 key_len = tcp_fastopen_get_cipher(net, icsk, key) *
4133                                 TCP_FASTOPEN_KEY_LENGTH;
4134                 len = min_t(unsigned int, len, key_len);
4135                 if (copy_to_sockptr(optlen, &len, sizeof(int)))
4136                         return -EFAULT;
4137                 if (copy_to_sockptr(optval, key, len))
4138                         return -EFAULT;
4139                 return 0;
4140         }
4141         case TCP_THIN_LINEAR_TIMEOUTS:
4142                 val = tp->thin_lto;
4143                 break;
4144
4145         case TCP_THIN_DUPACK:
4146                 val = 0;
4147                 break;
4148
4149         case TCP_REPAIR:
4150                 val = tp->repair;
4151                 break;
4152
4153         case TCP_REPAIR_QUEUE:
4154                 if (tp->repair)
4155                         val = tp->repair_queue;
4156                 else
4157                         return -EINVAL;
4158                 break;
4159
4160         case TCP_REPAIR_WINDOW: {
4161                 struct tcp_repair_window opt;
4162
4163                 if (copy_from_sockptr(&len, optlen, sizeof(int)))
4164                         return -EFAULT;
4165
4166                 if (len != sizeof(opt))
4167                         return -EINVAL;
4168
4169                 if (!tp->repair)
4170                         return -EPERM;
4171
4172                 opt.snd_wl1     = tp->snd_wl1;
4173                 opt.snd_wnd     = tp->snd_wnd;
4174                 opt.max_window  = tp->max_window;
4175                 opt.rcv_wnd     = tp->rcv_wnd;
4176                 opt.rcv_wup     = tp->rcv_wup;
4177
4178                 if (copy_to_sockptr(optval, &opt, len))
4179                         return -EFAULT;
4180                 return 0;
4181         }
4182         case TCP_QUEUE_SEQ:
4183                 if (tp->repair_queue == TCP_SEND_QUEUE)
4184                         val = tp->write_seq;
4185                 else if (tp->repair_queue == TCP_RECV_QUEUE)
4186                         val = tp->rcv_nxt;
4187                 else
4188                         return -EINVAL;
4189                 break;
4190
4191         case TCP_USER_TIMEOUT:
4192                 val = READ_ONCE(icsk->icsk_user_timeout);
4193                 break;
4194
4195         case TCP_FASTOPEN:
4196                 val = READ_ONCE(icsk->icsk_accept_queue.fastopenq.max_qlen);
4197                 break;
4198
4199         case TCP_FASTOPEN_CONNECT:
4200                 val = tp->fastopen_connect;
4201                 break;
4202
4203         case TCP_FASTOPEN_NO_COOKIE:
4204                 val = tp->fastopen_no_cookie;
4205                 break;
4206
4207         case TCP_TX_DELAY:
4208                 val = READ_ONCE(tp->tcp_tx_delay);
4209                 break;
4210
4211         case TCP_TIMESTAMP:
4212                 val = tcp_clock_ts(tp->tcp_usec_ts) + READ_ONCE(tp->tsoffset);
4213                 if (tp->tcp_usec_ts)
4214                         val |= 1;
4215                 else
4216                         val &= ~1;
4217                 break;
4218         case TCP_NOTSENT_LOWAT:
4219                 val = READ_ONCE(tp->notsent_lowat);
4220                 break;
4221         case TCP_INQ:
4222                 val = tp->recvmsg_inq;
4223                 break;
4224         case TCP_SAVE_SYN:
4225                 val = tp->save_syn;
4226                 break;
4227         case TCP_SAVED_SYN: {
4228                 if (copy_from_sockptr(&len, optlen, sizeof(int)))
4229                         return -EFAULT;
4230
4231                 sockopt_lock_sock(sk);
4232                 if (tp->saved_syn) {
4233                         if (len < tcp_saved_syn_len(tp->saved_syn)) {
4234                                 len = tcp_saved_syn_len(tp->saved_syn);
4235                                 if (copy_to_sockptr(optlen, &len, sizeof(int))) {
4236                                         sockopt_release_sock(sk);
4237                                         return -EFAULT;
4238                                 }
4239                                 sockopt_release_sock(sk);
4240                                 return -EINVAL;
4241                         }
4242                         len = tcp_saved_syn_len(tp->saved_syn);
4243                         if (copy_to_sockptr(optlen, &len, sizeof(int))) {
4244                                 sockopt_release_sock(sk);
4245                                 return -EFAULT;
4246                         }
4247                         if (copy_to_sockptr(optval, tp->saved_syn->data, len)) {
4248                                 sockopt_release_sock(sk);
4249                                 return -EFAULT;
4250                         }
4251                         tcp_saved_syn_free(tp);
4252                         sockopt_release_sock(sk);
4253                 } else {
4254                         sockopt_release_sock(sk);
4255                         len = 0;
4256                         if (copy_to_sockptr(optlen, &len, sizeof(int)))
4257                                 return -EFAULT;
4258                 }
4259                 return 0;
4260         }
4261 #ifdef CONFIG_MMU
4262         case TCP_ZEROCOPY_RECEIVE: {
4263                 struct scm_timestamping_internal tss;
4264                 struct tcp_zerocopy_receive zc = {};
4265                 int err;
4266
4267                 if (copy_from_sockptr(&len, optlen, sizeof(int)))
4268                         return -EFAULT;
4269                 if (len < 0 ||
4270                     len < offsetofend(struct tcp_zerocopy_receive, length))
4271                         return -EINVAL;
4272                 if (unlikely(len > sizeof(zc))) {
4273                         err = check_zeroed_sockptr(optval, sizeof(zc),
4274                                                    len - sizeof(zc));
4275                         if (err < 1)
4276                                 return err == 0 ? -EINVAL : err;
4277                         len = sizeof(zc);
4278                         if (copy_to_sockptr(optlen, &len, sizeof(int)))
4279                                 return -EFAULT;
4280                 }
4281                 if (copy_from_sockptr(&zc, optval, len))
4282                         return -EFAULT;
4283                 if (zc.reserved)
4284                         return -EINVAL;
4285                 if (zc.msg_flags &  ~(TCP_VALID_ZC_MSG_FLAGS))
4286                         return -EINVAL;
4287                 sockopt_lock_sock(sk);
4288                 err = tcp_zerocopy_receive(sk, &zc, &tss);
4289                 err = BPF_CGROUP_RUN_PROG_GETSOCKOPT_KERN(sk, level, optname,
4290                                                           &zc, &len, err);
4291                 sockopt_release_sock(sk);
4292                 if (len >= offsetofend(struct tcp_zerocopy_receive, msg_flags))
4293                         goto zerocopy_rcv_cmsg;
4294                 switch (len) {
4295                 case offsetofend(struct tcp_zerocopy_receive, msg_flags):
4296                         goto zerocopy_rcv_cmsg;
4297                 case offsetofend(struct tcp_zerocopy_receive, msg_controllen):
4298                 case offsetofend(struct tcp_zerocopy_receive, msg_control):
4299                 case offsetofend(struct tcp_zerocopy_receive, flags):
4300                 case offsetofend(struct tcp_zerocopy_receive, copybuf_len):
4301                 case offsetofend(struct tcp_zerocopy_receive, copybuf_address):
4302                 case offsetofend(struct tcp_zerocopy_receive, err):
4303                         goto zerocopy_rcv_sk_err;
4304                 case offsetofend(struct tcp_zerocopy_receive, inq):
4305                         goto zerocopy_rcv_inq;
4306                 case offsetofend(struct tcp_zerocopy_receive, length):
4307                 default:
4308                         goto zerocopy_rcv_out;
4309                 }
4310 zerocopy_rcv_cmsg:
4311                 if (zc.msg_flags & TCP_CMSG_TS)
4312                         tcp_zc_finalize_rx_tstamp(sk, &zc, &tss);
4313                 else
4314                         zc.msg_flags = 0;
4315 zerocopy_rcv_sk_err:
4316                 if (!err)
4317                         zc.err = sock_error(sk);
4318 zerocopy_rcv_inq:
4319                 zc.inq = tcp_inq_hint(sk);
4320 zerocopy_rcv_out:
4321                 if (!err && copy_to_sockptr(optval, &zc, len))
4322                         err = -EFAULT;
4323                 return err;
4324         }
4325 #endif
4326         case TCP_AO_REPAIR:
4327                 if (!tcp_can_repair_sock(sk))
4328                         return -EPERM;
4329                 return tcp_ao_get_repair(sk, optval, optlen);
4330         case TCP_AO_GET_KEYS:
4331         case TCP_AO_INFO: {
4332                 int err;
4333
4334                 sockopt_lock_sock(sk);
4335                 if (optname == TCP_AO_GET_KEYS)
4336                         err = tcp_ao_get_mkts(sk, optval, optlen);
4337                 else
4338                         err = tcp_ao_get_sock_info(sk, optval, optlen);
4339                 sockopt_release_sock(sk);
4340
4341                 return err;
4342         }
4343         default:
4344                 return -ENOPROTOOPT;
4345         }
4346
4347         if (copy_to_sockptr(optlen, &len, sizeof(int)))
4348                 return -EFAULT;
4349         if (copy_to_sockptr(optval, &val, len))
4350                 return -EFAULT;
4351         return 0;
4352 }
4353
4354 bool tcp_bpf_bypass_getsockopt(int level, int optname)
4355 {
4356         /* TCP do_tcp_getsockopt has optimized getsockopt implementation
4357          * to avoid extra socket lock for TCP_ZEROCOPY_RECEIVE.
4358          */
4359         if (level == SOL_TCP && optname == TCP_ZEROCOPY_RECEIVE)
4360                 return true;
4361
4362         return false;
4363 }
4364 EXPORT_SYMBOL(tcp_bpf_bypass_getsockopt);
4365
4366 int tcp_getsockopt(struct sock *sk, int level, int optname, char __user *optval,
4367                    int __user *optlen)
4368 {
4369         struct inet_connection_sock *icsk = inet_csk(sk);
4370
4371         if (level != SOL_TCP)
4372                 /* Paired with WRITE_ONCE() in do_ipv6_setsockopt() and tcp_v6_connect() */
4373                 return READ_ONCE(icsk->icsk_af_ops)->getsockopt(sk, level, optname,
4374                                                                 optval, optlen);
4375         return do_tcp_getsockopt(sk, level, optname, USER_SOCKPTR(optval),
4376                                  USER_SOCKPTR(optlen));
4377 }
4378 EXPORT_SYMBOL(tcp_getsockopt);
4379
4380 #ifdef CONFIG_TCP_MD5SIG
4381 int tcp_md5_sigpool_id = -1;
4382 EXPORT_SYMBOL_GPL(tcp_md5_sigpool_id);
4383
4384 int tcp_md5_alloc_sigpool(void)
4385 {
4386         size_t scratch_size;
4387         int ret;
4388
4389         scratch_size = sizeof(union tcp_md5sum_block) + sizeof(struct tcphdr);
4390         ret = tcp_sigpool_alloc_ahash("md5", scratch_size);
4391         if (ret >= 0) {
4392                 /* As long as any md5 sigpool was allocated, the return
4393                  * id would stay the same. Re-write the id only for the case
4394                  * when previously all MD5 keys were deleted and this call
4395                  * allocates the first MD5 key, which may return a different
4396                  * sigpool id than was used previously.
4397                  */
4398                 WRITE_ONCE(tcp_md5_sigpool_id, ret); /* Avoids the compiler potentially being smart here */
4399                 return 0;
4400         }
4401         return ret;
4402 }
4403
4404 void tcp_md5_release_sigpool(void)
4405 {
4406         tcp_sigpool_release(READ_ONCE(tcp_md5_sigpool_id));
4407 }
4408
4409 void tcp_md5_add_sigpool(void)
4410 {
4411         tcp_sigpool_get(READ_ONCE(tcp_md5_sigpool_id));
4412 }
4413
4414 int tcp_md5_hash_key(struct tcp_sigpool *hp,
4415                      const struct tcp_md5sig_key *key)
4416 {
4417         u8 keylen = READ_ONCE(key->keylen); /* paired with WRITE_ONCE() in tcp_md5_do_add */
4418         struct scatterlist sg;
4419
4420         sg_init_one(&sg, key->key, keylen);
4421         ahash_request_set_crypt(hp->req, &sg, NULL, keylen);
4422
4423         /* We use data_race() because tcp_md5_do_add() might change
4424          * key->key under us
4425          */
4426         return data_race(crypto_ahash_update(hp->req));
4427 }
4428 EXPORT_SYMBOL(tcp_md5_hash_key);
4429
4430 /* Called with rcu_read_lock() */
4431 enum skb_drop_reason
4432 tcp_inbound_md5_hash(const struct sock *sk, const struct sk_buff *skb,
4433                      const void *saddr, const void *daddr,
4434                      int family, int l3index, const __u8 *hash_location)
4435 {
4436         /* This gets called for each TCP segment that has TCP-MD5 option.
4437          * We have 3 drop cases:
4438          * o No MD5 hash and one expected.
4439          * o MD5 hash and we're not expecting one.
4440          * o MD5 hash and its wrong.
4441          */
4442         const struct tcp_sock *tp = tcp_sk(sk);
4443         struct tcp_md5sig_key *key;
4444         u8 newhash[16];
4445         int genhash;
4446
4447         key = tcp_md5_do_lookup(sk, l3index, saddr, family);
4448
4449         if (!key && hash_location) {
4450                 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5UNEXPECTED);
4451                 tcp_hash_fail("Unexpected MD5 Hash found", family, skb, "");
4452                 return SKB_DROP_REASON_TCP_MD5UNEXPECTED;
4453         }
4454
4455         /* Check the signature.
4456          * To support dual stack listeners, we need to handle
4457          * IPv4-mapped case.
4458          */
4459         if (family == AF_INET)
4460                 genhash = tcp_v4_md5_hash_skb(newhash, key, NULL, skb);
4461         else
4462                 genhash = tp->af_specific->calc_md5_hash(newhash, key,
4463                                                          NULL, skb);
4464         if (genhash || memcmp(hash_location, newhash, 16) != 0) {
4465                 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5FAILURE);
4466                 if (family == AF_INET) {
4467                         tcp_hash_fail("MD5 Hash failed", AF_INET, skb, "%s L3 index %d",
4468                                       genhash ? "tcp_v4_calc_md5_hash failed"
4469                                       : "", l3index);
4470                 } else {
4471                         if (genhash) {
4472                                 tcp_hash_fail("MD5 Hash failed",
4473                                               AF_INET6, skb, "L3 index %d",
4474                                               l3index);
4475                         } else {
4476                                 tcp_hash_fail("MD5 Hash mismatch",
4477                                               AF_INET6, skb, "L3 index %d",
4478                                               l3index);
4479                         }
4480                 }
4481                 return SKB_DROP_REASON_TCP_MD5FAILURE;
4482         }
4483         return SKB_NOT_DROPPED_YET;
4484 }
4485 EXPORT_SYMBOL(tcp_inbound_md5_hash);
4486
4487 #endif
4488
4489 void tcp_done(struct sock *sk)
4490 {
4491         struct request_sock *req;
4492
4493         /* We might be called with a new socket, after
4494          * inet_csk_prepare_forced_close() has been called
4495          * so we can not use lockdep_sock_is_held(sk)
4496          */
4497         req = rcu_dereference_protected(tcp_sk(sk)->fastopen_rsk, 1);
4498
4499         if (sk->sk_state == TCP_SYN_SENT || sk->sk_state == TCP_SYN_RECV)
4500                 TCP_INC_STATS(sock_net(sk), TCP_MIB_ATTEMPTFAILS);
4501
4502         tcp_set_state(sk, TCP_CLOSE);
4503         tcp_clear_xmit_timers(sk);
4504         if (req)
4505                 reqsk_fastopen_remove(sk, req, false);
4506
4507         WRITE_ONCE(sk->sk_shutdown, SHUTDOWN_MASK);
4508
4509         if (!sock_flag(sk, SOCK_DEAD))
4510                 sk->sk_state_change(sk);
4511         else
4512                 inet_csk_destroy_sock(sk);
4513 }
4514 EXPORT_SYMBOL_GPL(tcp_done);
4515
4516 int tcp_abort(struct sock *sk, int err)
4517 {
4518         int state = inet_sk_state_load(sk);
4519
4520         if (state == TCP_NEW_SYN_RECV) {
4521                 struct request_sock *req = inet_reqsk(sk);
4522
4523                 local_bh_disable();
4524                 inet_csk_reqsk_queue_drop(req->rsk_listener, req);
4525                 local_bh_enable();
4526                 return 0;
4527         }
4528         if (state == TCP_TIME_WAIT) {
4529                 struct inet_timewait_sock *tw = inet_twsk(sk);
4530
4531                 refcount_inc(&tw->tw_refcnt);
4532                 local_bh_disable();
4533                 inet_twsk_deschedule_put(tw);
4534                 local_bh_enable();
4535                 return 0;
4536         }
4537
4538         /* BPF context ensures sock locking. */
4539         if (!has_current_bpf_ctx())
4540                 /* Don't race with userspace socket closes such as tcp_close. */
4541                 lock_sock(sk);
4542
4543         if (sk->sk_state == TCP_LISTEN) {
4544                 tcp_set_state(sk, TCP_CLOSE);
4545                 inet_csk_listen_stop(sk);
4546         }
4547
4548         /* Don't race with BH socket closes such as inet_csk_listen_stop. */
4549         local_bh_disable();
4550         bh_lock_sock(sk);
4551
4552         if (!sock_flag(sk, SOCK_DEAD)) {
4553                 WRITE_ONCE(sk->sk_err, err);
4554                 /* This barrier is coupled with smp_rmb() in tcp_poll() */
4555                 smp_wmb();
4556                 sk_error_report(sk);
4557                 if (tcp_need_reset(sk->sk_state))
4558                         tcp_send_active_reset(sk, GFP_ATOMIC);
4559                 tcp_done(sk);
4560         }
4561
4562         bh_unlock_sock(sk);
4563         local_bh_enable();
4564         tcp_write_queue_purge(sk);
4565         if (!has_current_bpf_ctx())
4566                 release_sock(sk);
4567         return 0;
4568 }
4569 EXPORT_SYMBOL_GPL(tcp_abort);
4570
4571 extern struct tcp_congestion_ops tcp_reno;
4572
4573 static __initdata unsigned long thash_entries;
4574 static int __init set_thash_entries(char *str)
4575 {
4576         ssize_t ret;
4577
4578         if (!str)
4579                 return 0;
4580
4581         ret = kstrtoul(str, 0, &thash_entries);
4582         if (ret)
4583                 return 0;
4584
4585         return 1;
4586 }
4587 __setup("thash_entries=", set_thash_entries);
4588
4589 static void __init tcp_init_mem(void)
4590 {
4591         unsigned long limit = nr_free_buffer_pages() / 16;
4592
4593         limit = max(limit, 128UL);
4594         sysctl_tcp_mem[0] = limit / 4 * 3;              /* 4.68 % */
4595         sysctl_tcp_mem[1] = limit;                      /* 6.25 % */
4596         sysctl_tcp_mem[2] = sysctl_tcp_mem[0] * 2;      /* 9.37 % */
4597 }
4598
4599 static void __init tcp_struct_check(void)
4600 {
4601         /* TX read-mostly hotpath cache lines */
4602         CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_read_tx, max_window);
4603         CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_read_tx, rcv_ssthresh);
4604         CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_read_tx, reordering);
4605         CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_read_tx, notsent_lowat);
4606         CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_read_tx, gso_segs);
4607         CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_read_tx, lost_skb_hint);
4608         CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_read_tx, retransmit_skb_hint);
4609         CACHELINE_ASSERT_GROUP_SIZE(struct tcp_sock, tcp_sock_read_tx, 40);
4610
4611         /* TXRX read-mostly hotpath cache lines */
4612         CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_read_txrx, tsoffset);
4613         CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_read_txrx, snd_wnd);
4614         CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_read_txrx, mss_cache);
4615         CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_read_txrx, snd_cwnd);
4616         CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_read_txrx, prr_out);
4617         CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_read_txrx, lost_out);
4618         CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_read_txrx, sacked_out);
4619         CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_read_txrx, scaling_ratio);
4620         CACHELINE_ASSERT_GROUP_SIZE(struct tcp_sock, tcp_sock_read_txrx, 32);
4621
4622         /* RX read-mostly hotpath cache lines */
4623         CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_read_rx, copied_seq);
4624         CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_read_rx, rcv_tstamp);
4625         CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_read_rx, snd_wl1);
4626         CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_read_rx, tlp_high_seq);
4627         CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_read_rx, rttvar_us);
4628         CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_read_rx, retrans_out);
4629         CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_read_rx, advmss);
4630         CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_read_rx, urg_data);
4631         CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_read_rx, lost);
4632         CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_read_rx, rtt_min);
4633         CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_read_rx, out_of_order_queue);
4634         CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_read_rx, snd_ssthresh);
4635         CACHELINE_ASSERT_GROUP_SIZE(struct tcp_sock, tcp_sock_read_rx, 69);
4636
4637         /* TX read-write hotpath cache lines */
4638         CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_write_tx, segs_out);
4639         CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_write_tx, data_segs_out);
4640         CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_write_tx, bytes_sent);
4641         CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_write_tx, snd_sml);
4642         CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_write_tx, chrono_start);
4643         CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_write_tx, chrono_stat);
4644         CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_write_tx, write_seq);
4645         CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_write_tx, pushed_seq);
4646         CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_write_tx, lsndtime);
4647         CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_write_tx, mdev_us);
4648         CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_write_tx, tcp_wstamp_ns);
4649         CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_write_tx, tcp_clock_cache);
4650         CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_write_tx, tcp_mstamp);
4651         CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_write_tx, rtt_seq);
4652         CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_write_tx, tsorted_sent_queue);
4653         CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_write_tx, highest_sack);
4654         CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_write_tx, ecn_flags);
4655         CACHELINE_ASSERT_GROUP_SIZE(struct tcp_sock, tcp_sock_write_tx, 105);
4656
4657         /* TXRX read-write hotpath cache lines */
4658         CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_write_txrx, pred_flags);
4659         CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_write_txrx, rcv_nxt);
4660         CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_write_txrx, snd_nxt);
4661         CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_write_txrx, snd_una);
4662         CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_write_txrx, window_clamp);
4663         CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_write_txrx, srtt_us);
4664         CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_write_txrx, packets_out);
4665         CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_write_txrx, snd_up);
4666         CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_write_txrx, delivered);
4667         CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_write_txrx, delivered_ce);
4668         CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_write_txrx, app_limited);
4669         CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_write_txrx, rcv_wnd);
4670         CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_write_txrx, rx_opt);
4671         CACHELINE_ASSERT_GROUP_SIZE(struct tcp_sock, tcp_sock_write_txrx, 76);
4672
4673         /* RX read-write hotpath cache lines */
4674         CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_write_rx, bytes_received);
4675         CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_write_rx, segs_in);
4676         CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_write_rx, data_segs_in);
4677         CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_write_rx, rcv_wup);
4678         CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_write_rx, max_packets_out);
4679         CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_write_rx, cwnd_usage_seq);
4680         CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_write_rx, rate_delivered);
4681         CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_write_rx, rate_interval_us);
4682         CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_write_rx, rcv_rtt_last_tsecr);
4683         CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_write_rx, first_tx_mstamp);
4684         CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_write_rx, delivered_mstamp);
4685         CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_write_rx, bytes_acked);
4686         CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_write_rx, rcv_rtt_est);
4687         CACHELINE_ASSERT_GROUP_MEMBER(struct tcp_sock, tcp_sock_write_rx, rcvq_space);
4688         CACHELINE_ASSERT_GROUP_SIZE(struct tcp_sock, tcp_sock_write_rx, 99);
4689 }
4690
4691 void __init tcp_init(void)
4692 {
4693         int max_rshare, max_wshare, cnt;
4694         unsigned long limit;
4695         unsigned int i;
4696
4697         BUILD_BUG_ON(TCP_MIN_SND_MSS <= MAX_TCP_OPTION_SPACE);
4698         BUILD_BUG_ON(sizeof(struct tcp_skb_cb) >
4699                      sizeof_field(struct sk_buff, cb));
4700
4701         tcp_struct_check();
4702
4703         percpu_counter_init(&tcp_sockets_allocated, 0, GFP_KERNEL);
4704
4705         timer_setup(&tcp_orphan_timer, tcp_orphan_update, TIMER_DEFERRABLE);
4706         mod_timer(&tcp_orphan_timer, jiffies + TCP_ORPHAN_TIMER_PERIOD);
4707
4708         inet_hashinfo2_init(&tcp_hashinfo, "tcp_listen_portaddr_hash",
4709                             thash_entries, 21,  /* one slot per 2 MB*/
4710                             0, 64 * 1024);
4711         tcp_hashinfo.bind_bucket_cachep =
4712                 kmem_cache_create("tcp_bind_bucket",
4713                                   sizeof(struct inet_bind_bucket), 0,
4714                                   SLAB_HWCACHE_ALIGN | SLAB_PANIC |
4715                                   SLAB_ACCOUNT,
4716                                   NULL);
4717         tcp_hashinfo.bind2_bucket_cachep =
4718                 kmem_cache_create("tcp_bind2_bucket",
4719                                   sizeof(struct inet_bind2_bucket), 0,
4720                                   SLAB_HWCACHE_ALIGN | SLAB_PANIC |
4721                                   SLAB_ACCOUNT,
4722                                   NULL);
4723
4724         /* Size and allocate the main established and bind bucket
4725          * hash tables.
4726          *
4727          * The methodology is similar to that of the buffer cache.
4728          */
4729         tcp_hashinfo.ehash =
4730                 alloc_large_system_hash("TCP established",
4731                                         sizeof(struct inet_ehash_bucket),
4732                                         thash_entries,
4733                                         17, /* one slot per 128 KB of memory */
4734                                         0,
4735                                         NULL,
4736                                         &tcp_hashinfo.ehash_mask,
4737                                         0,
4738                                         thash_entries ? 0 : 512 * 1024);
4739         for (i = 0; i <= tcp_hashinfo.ehash_mask; i++)
4740                 INIT_HLIST_NULLS_HEAD(&tcp_hashinfo.ehash[i].chain, i);
4741
4742         if (inet_ehash_locks_alloc(&tcp_hashinfo))
4743                 panic("TCP: failed to alloc ehash_locks");
4744         tcp_hashinfo.bhash =
4745                 alloc_large_system_hash("TCP bind",
4746                                         2 * sizeof(struct inet_bind_hashbucket),
4747                                         tcp_hashinfo.ehash_mask + 1,
4748                                         17, /* one slot per 128 KB of memory */
4749                                         0,
4750                                         &tcp_hashinfo.bhash_size,
4751                                         NULL,
4752                                         0,
4753                                         64 * 1024);
4754         tcp_hashinfo.bhash_size = 1U << tcp_hashinfo.bhash_size;
4755         tcp_hashinfo.bhash2 = tcp_hashinfo.bhash + tcp_hashinfo.bhash_size;
4756         for (i = 0; i < tcp_hashinfo.bhash_size; i++) {
4757                 spin_lock_init(&tcp_hashinfo.bhash[i].lock);
4758                 INIT_HLIST_HEAD(&tcp_hashinfo.bhash[i].chain);
4759                 spin_lock_init(&tcp_hashinfo.bhash2[i].lock);
4760                 INIT_HLIST_HEAD(&tcp_hashinfo.bhash2[i].chain);
4761         }
4762
4763         tcp_hashinfo.pernet = false;
4764
4765         cnt = tcp_hashinfo.ehash_mask + 1;
4766         sysctl_tcp_max_orphans = cnt / 2;
4767
4768         tcp_init_mem();
4769         /* Set per-socket limits to no more than 1/128 the pressure threshold */
4770         limit = nr_free_buffer_pages() << (PAGE_SHIFT - 7);
4771         max_wshare = min(4UL*1024*1024, limit);
4772         max_rshare = min(6UL*1024*1024, limit);
4773
4774         init_net.ipv4.sysctl_tcp_wmem[0] = PAGE_SIZE;
4775         init_net.ipv4.sysctl_tcp_wmem[1] = 16*1024;
4776         init_net.ipv4.sysctl_tcp_wmem[2] = max(64*1024, max_wshare);
4777
4778         init_net.ipv4.sysctl_tcp_rmem[0] = PAGE_SIZE;
4779         init_net.ipv4.sysctl_tcp_rmem[1] = 131072;
4780         init_net.ipv4.sysctl_tcp_rmem[2] = max(131072, max_rshare);
4781
4782         pr_info("Hash tables configured (established %u bind %u)\n",
4783                 tcp_hashinfo.ehash_mask + 1, tcp_hashinfo.bhash_size);
4784
4785         tcp_v4_init();
4786         tcp_metrics_init();
4787         BUG_ON(tcp_register_congestion_control(&tcp_reno) != 0);
4788         tcp_tasklet_init();
4789         mptcp_init();
4790 }