Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6
[sfrench/cifs-2.6.git] / net / ipv4 / tcp.c
1 /*
2  * INET         An implementation of the TCP/IP protocol suite for the LINUX
3  *              operating system.  INET is implemented using the  BSD Socket
4  *              interface as the means of communication with the user level.
5  *
6  *              Implementation of the Transmission Control Protocol(TCP).
7  *
8  * Authors:     Ross Biro
9  *              Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
10  *              Mark Evans, <evansmp@uhura.aston.ac.uk>
11  *              Corey Minyard <wf-rch!minyard@relay.EU.net>
12  *              Florian La Roche, <flla@stud.uni-sb.de>
13  *              Charles Hedrick, <hedrick@klinzhai.rutgers.edu>
14  *              Linus Torvalds, <torvalds@cs.helsinki.fi>
15  *              Alan Cox, <gw4pts@gw4pts.ampr.org>
16  *              Matthew Dillon, <dillon@apollo.west.oic.com>
17  *              Arnt Gulbrandsen, <agulbra@nvg.unit.no>
18  *              Jorge Cwik, <jorge@laser.satlink.net>
19  *
20  * Fixes:
21  *              Alan Cox        :       Numerous verify_area() calls
22  *              Alan Cox        :       Set the ACK bit on a reset
23  *              Alan Cox        :       Stopped it crashing if it closed while
24  *                                      sk->inuse=1 and was trying to connect
25  *                                      (tcp_err()).
26  *              Alan Cox        :       All icmp error handling was broken
27  *                                      pointers passed where wrong and the
28  *                                      socket was looked up backwards. Nobody
29  *                                      tested any icmp error code obviously.
30  *              Alan Cox        :       tcp_err() now handled properly. It
31  *                                      wakes people on errors. poll
32  *                                      behaves and the icmp error race
33  *                                      has gone by moving it into sock.c
34  *              Alan Cox        :       tcp_send_reset() fixed to work for
35  *                                      everything not just packets for
36  *                                      unknown sockets.
37  *              Alan Cox        :       tcp option processing.
38  *              Alan Cox        :       Reset tweaked (still not 100%) [Had
39  *                                      syn rule wrong]
40  *              Herp Rosmanith  :       More reset fixes
41  *              Alan Cox        :       No longer acks invalid rst frames.
42  *                                      Acking any kind of RST is right out.
43  *              Alan Cox        :       Sets an ignore me flag on an rst
44  *                                      receive otherwise odd bits of prattle
45  *                                      escape still
46  *              Alan Cox        :       Fixed another acking RST frame bug.
47  *                                      Should stop LAN workplace lockups.
48  *              Alan Cox        :       Some tidyups using the new skb list
49  *                                      facilities
50  *              Alan Cox        :       sk->keepopen now seems to work
51  *              Alan Cox        :       Pulls options out correctly on accepts
52  *              Alan Cox        :       Fixed assorted sk->rqueue->next errors
53  *              Alan Cox        :       PSH doesn't end a TCP read. Switched a
54  *                                      bit to skb ops.
55  *              Alan Cox        :       Tidied tcp_data to avoid a potential
56  *                                      nasty.
57  *              Alan Cox        :       Added some better commenting, as the
58  *                                      tcp is hard to follow
59  *              Alan Cox        :       Removed incorrect check for 20 * psh
60  *      Michael O'Reilly        :       ack < copied bug fix.
61  *      Johannes Stille         :       Misc tcp fixes (not all in yet).
62  *              Alan Cox        :       FIN with no memory -> CRASH
63  *              Alan Cox        :       Added socket option proto entries.
64  *                                      Also added awareness of them to accept.
65  *              Alan Cox        :       Added TCP options (SOL_TCP)
66  *              Alan Cox        :       Switched wakeup calls to callbacks,
67  *                                      so the kernel can layer network
68  *                                      sockets.
69  *              Alan Cox        :       Use ip_tos/ip_ttl settings.
70  *              Alan Cox        :       Handle FIN (more) properly (we hope).
71  *              Alan Cox        :       RST frames sent on unsynchronised
72  *                                      state ack error.
73  *              Alan Cox        :       Put in missing check for SYN bit.
74  *              Alan Cox        :       Added tcp_select_window() aka NET2E
75  *                                      window non shrink trick.
76  *              Alan Cox        :       Added a couple of small NET2E timer
77  *                                      fixes
78  *              Charles Hedrick :       TCP fixes
79  *              Toomas Tamm     :       TCP window fixes
80  *              Alan Cox        :       Small URG fix to rlogin ^C ack fight
81  *              Charles Hedrick :       Rewrote most of it to actually work
82  *              Linus           :       Rewrote tcp_read() and URG handling
83  *                                      completely
84  *              Gerhard Koerting:       Fixed some missing timer handling
85  *              Matthew Dillon  :       Reworked TCP machine states as per RFC
86  *              Gerhard Koerting:       PC/TCP workarounds
87  *              Adam Caldwell   :       Assorted timer/timing errors
88  *              Matthew Dillon  :       Fixed another RST bug
89  *              Alan Cox        :       Move to kernel side addressing changes.
90  *              Alan Cox        :       Beginning work on TCP fastpathing
91  *                                      (not yet usable)
92  *              Arnt Gulbrandsen:       Turbocharged tcp_check() routine.
93  *              Alan Cox        :       TCP fast path debugging
94  *              Alan Cox        :       Window clamping
95  *              Michael Riepe   :       Bug in tcp_check()
96  *              Matt Dillon     :       More TCP improvements and RST bug fixes
97  *              Matt Dillon     :       Yet more small nasties remove from the
98  *                                      TCP code (Be very nice to this man if
99  *                                      tcp finally works 100%) 8)
100  *              Alan Cox        :       BSD accept semantics.
101  *              Alan Cox        :       Reset on closedown bug.
102  *      Peter De Schrijver      :       ENOTCONN check missing in tcp_sendto().
103  *              Michael Pall    :       Handle poll() after URG properly in
104  *                                      all cases.
105  *              Michael Pall    :       Undo the last fix in tcp_read_urg()
106  *                                      (multi URG PUSH broke rlogin).
107  *              Michael Pall    :       Fix the multi URG PUSH problem in
108  *                                      tcp_readable(), poll() after URG
109  *                                      works now.
110  *              Michael Pall    :       recv(...,MSG_OOB) never blocks in the
111  *                                      BSD api.
112  *              Alan Cox        :       Changed the semantics of sk->socket to
113  *                                      fix a race and a signal problem with
114  *                                      accept() and async I/O.
115  *              Alan Cox        :       Relaxed the rules on tcp_sendto().
116  *              Yury Shevchuk   :       Really fixed accept() blocking problem.
117  *              Craig I. Hagan  :       Allow for BSD compatible TIME_WAIT for
118  *                                      clients/servers which listen in on
119  *                                      fixed ports.
120  *              Alan Cox        :       Cleaned the above up and shrank it to
121  *                                      a sensible code size.
122  *              Alan Cox        :       Self connect lockup fix.
123  *              Alan Cox        :       No connect to multicast.
124  *              Ross Biro       :       Close unaccepted children on master
125  *                                      socket close.
126  *              Alan Cox        :       Reset tracing code.
127  *              Alan Cox        :       Spurious resets on shutdown.
128  *              Alan Cox        :       Giant 15 minute/60 second timer error
129  *              Alan Cox        :       Small whoops in polling before an
130  *                                      accept.
131  *              Alan Cox        :       Kept the state trace facility since
132  *                                      it's handy for debugging.
133  *              Alan Cox        :       More reset handler fixes.
134  *              Alan Cox        :       Started rewriting the code based on
135  *                                      the RFC's for other useful protocol
136  *                                      references see: Comer, KA9Q NOS, and
137  *                                      for a reference on the difference
138  *                                      between specifications and how BSD
139  *                                      works see the 4.4lite source.
140  *              A.N.Kuznetsov   :       Don't time wait on completion of tidy
141  *                                      close.
142  *              Linus Torvalds  :       Fin/Shutdown & copied_seq changes.
143  *              Linus Torvalds  :       Fixed BSD port reuse to work first syn
144  *              Alan Cox        :       Reimplemented timers as per the RFC
145  *                                      and using multiple timers for sanity.
146  *              Alan Cox        :       Small bug fixes, and a lot of new
147  *                                      comments.
148  *              Alan Cox        :       Fixed dual reader crash by locking
149  *                                      the buffers (much like datagram.c)
150  *              Alan Cox        :       Fixed stuck sockets in probe. A probe
151  *                                      now gets fed up of retrying without
152  *                                      (even a no space) answer.
153  *              Alan Cox        :       Extracted closing code better
154  *              Alan Cox        :       Fixed the closing state machine to
155  *                                      resemble the RFC.
156  *              Alan Cox        :       More 'per spec' fixes.
157  *              Jorge Cwik      :       Even faster checksumming.
158  *              Alan Cox        :       tcp_data() doesn't ack illegal PSH
159  *                                      only frames. At least one pc tcp stack
160  *                                      generates them.
161  *              Alan Cox        :       Cache last socket.
162  *              Alan Cox        :       Per route irtt.
163  *              Matt Day        :       poll()->select() match BSD precisely on error
164  *              Alan Cox        :       New buffers
165  *              Marc Tamsky     :       Various sk->prot->retransmits and
166  *                                      sk->retransmits misupdating fixed.
167  *                                      Fixed tcp_write_timeout: stuck close,
168  *                                      and TCP syn retries gets used now.
169  *              Mark Yarvis     :       In tcp_read_wakeup(), don't send an
170  *                                      ack if state is TCP_CLOSED.
171  *              Alan Cox        :       Look up device on a retransmit - routes may
172  *                                      change. Doesn't yet cope with MSS shrink right
173  *                                      but it's a start!
174  *              Marc Tamsky     :       Closing in closing fixes.
175  *              Mike Shaver     :       RFC1122 verifications.
176  *              Alan Cox        :       rcv_saddr errors.
177  *              Alan Cox        :       Block double connect().
178  *              Alan Cox        :       Small hooks for enSKIP.
179  *              Alexey Kuznetsov:       Path MTU discovery.
180  *              Alan Cox        :       Support soft errors.
181  *              Alan Cox        :       Fix MTU discovery pathological case
182  *                                      when the remote claims no mtu!
183  *              Marc Tamsky     :       TCP_CLOSE fix.
184  *              Colin (G3TNE)   :       Send a reset on syn ack replies in
185  *                                      window but wrong (fixes NT lpd problems)
186  *              Pedro Roque     :       Better TCP window handling, delayed ack.
187  *              Joerg Reuter    :       No modification of locked buffers in
188  *                                      tcp_do_retransmit()
189  *              Eric Schenk     :       Changed receiver side silly window
190  *                                      avoidance algorithm to BSD style
191  *                                      algorithm. This doubles throughput
192  *                                      against machines running Solaris,
193  *                                      and seems to result in general
194  *                                      improvement.
195  *      Stefan Magdalinski      :       adjusted tcp_readable() to fix FIONREAD
196  *      Willy Konynenberg       :       Transparent proxying support.
197  *      Mike McLagan            :       Routing by source
198  *              Keith Owens     :       Do proper merging with partial SKB's in
199  *                                      tcp_do_sendmsg to avoid burstiness.
200  *              Eric Schenk     :       Fix fast close down bug with
201  *                                      shutdown() followed by close().
202  *              Andi Kleen      :       Make poll agree with SIGIO
203  *      Salvatore Sanfilippo    :       Support SO_LINGER with linger == 1 and
204  *                                      lingertime == 0 (RFC 793 ABORT Call)
205  *      Hirokazu Takahashi      :       Use copy_from_user() instead of
206  *                                      csum_and_copy_from_user() if possible.
207  *
208  *              This program is free software; you can redistribute it and/or
209  *              modify it under the terms of the GNU General Public License
210  *              as published by the Free Software Foundation; either version
211  *              2 of the License, or(at your option) any later version.
212  *
213  * Description of States:
214  *
215  *      TCP_SYN_SENT            sent a connection request, waiting for ack
216  *
217  *      TCP_SYN_RECV            received a connection request, sent ack,
218  *                              waiting for final ack in three-way handshake.
219  *
220  *      TCP_ESTABLISHED         connection established
221  *
222  *      TCP_FIN_WAIT1           our side has shutdown, waiting to complete
223  *                              transmission of remaining buffered data
224  *
225  *      TCP_FIN_WAIT2           all buffered data sent, waiting for remote
226  *                              to shutdown
227  *
228  *      TCP_CLOSING             both sides have shutdown but we still have
229  *                              data we have to finish sending
230  *
231  *      TCP_TIME_WAIT           timeout to catch resent junk before entering
232  *                              closed, can only be entered from FIN_WAIT2
233  *                              or CLOSING.  Required because the other end
234  *                              may not have gotten our last ACK causing it
235  *                              to retransmit the data packet (which we ignore)
236  *
237  *      TCP_CLOSE_WAIT          remote side has shutdown and is waiting for
238  *                              us to finish writing our data and to shutdown
239  *                              (we have to close() to move on to LAST_ACK)
240  *
241  *      TCP_LAST_ACK            out side has shutdown after remote has
242  *                              shutdown.  There may still be data in our
243  *                              buffer that we have to finish sending
244  *
245  *      TCP_CLOSE               socket is finished
246  */
247
248 #include <linux/kernel.h>
249 #include <linux/module.h>
250 #include <linux/types.h>
251 #include <linux/fcntl.h>
252 #include <linux/poll.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/bootmem.h>
262 #include <linux/highmem.h>
263 #include <linux/swap.h>
264 #include <linux/cache.h>
265 #include <linux/err.h>
266 #include <linux/crypto.h>
267 #include <linux/time.h>
268 #include <linux/slab.h>
269
270 #include <net/icmp.h>
271 #include <net/tcp.h>
272 #include <net/xfrm.h>
273 #include <net/ip.h>
274 #include <net/netdma.h>
275 #include <net/sock.h>
276
277 #include <asm/uaccess.h>
278 #include <asm/ioctls.h>
279
280 int sysctl_tcp_fin_timeout __read_mostly = TCP_FIN_TIMEOUT;
281
282 struct percpu_counter tcp_orphan_count;
283 EXPORT_SYMBOL_GPL(tcp_orphan_count);
284
285 int sysctl_tcp_mem[3] __read_mostly;
286 int sysctl_tcp_wmem[3] __read_mostly;
287 int sysctl_tcp_rmem[3] __read_mostly;
288
289 EXPORT_SYMBOL(sysctl_tcp_mem);
290 EXPORT_SYMBOL(sysctl_tcp_rmem);
291 EXPORT_SYMBOL(sysctl_tcp_wmem);
292
293 atomic_t tcp_memory_allocated;  /* Current allocated memory. */
294 EXPORT_SYMBOL(tcp_memory_allocated);
295
296 /*
297  * Current number of TCP sockets.
298  */
299 struct percpu_counter tcp_sockets_allocated;
300 EXPORT_SYMBOL(tcp_sockets_allocated);
301
302 /*
303  * TCP splice context
304  */
305 struct tcp_splice_state {
306         struct pipe_inode_info *pipe;
307         size_t len;
308         unsigned int flags;
309 };
310
311 /*
312  * Pressure flag: try to collapse.
313  * Technical note: it is used by multiple contexts non atomically.
314  * All the __sk_mem_schedule() is of this nature: accounting
315  * is strict, actions are advisory and have some latency.
316  */
317 int tcp_memory_pressure __read_mostly;
318 EXPORT_SYMBOL(tcp_memory_pressure);
319
320 void tcp_enter_memory_pressure(struct sock *sk)
321 {
322         if (!tcp_memory_pressure) {
323                 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMEMORYPRESSURES);
324                 tcp_memory_pressure = 1;
325         }
326 }
327 EXPORT_SYMBOL(tcp_enter_memory_pressure);
328
329 /* Convert seconds to retransmits based on initial and max timeout */
330 static u8 secs_to_retrans(int seconds, int timeout, int rto_max)
331 {
332         u8 res = 0;
333
334         if (seconds > 0) {
335                 int period = timeout;
336
337                 res = 1;
338                 while (seconds > period && res < 255) {
339                         res++;
340                         timeout <<= 1;
341                         if (timeout > rto_max)
342                                 timeout = rto_max;
343                         period += timeout;
344                 }
345         }
346         return res;
347 }
348
349 /* Convert retransmits to seconds based on initial and max timeout */
350 static int retrans_to_secs(u8 retrans, int timeout, int rto_max)
351 {
352         int period = 0;
353
354         if (retrans > 0) {
355                 period = timeout;
356                 while (--retrans) {
357                         timeout <<= 1;
358                         if (timeout > rto_max)
359                                 timeout = rto_max;
360                         period += timeout;
361                 }
362         }
363         return period;
364 }
365
366 /*
367  *      Wait for a TCP event.
368  *
369  *      Note that we don't need to lock the socket, as the upper poll layers
370  *      take care of normal races (between the test and the event) and we don't
371  *      go look at any of the socket buffers directly.
372  */
373 unsigned int tcp_poll(struct file *file, struct socket *sock, poll_table *wait)
374 {
375         unsigned int mask;
376         struct sock *sk = sock->sk;
377         struct tcp_sock *tp = tcp_sk(sk);
378
379         sock_poll_wait(file, sk_sleep(sk), wait);
380         if (sk->sk_state == TCP_LISTEN)
381                 return inet_csk_listen_poll(sk);
382
383         /* Socket is not locked. We are protected from async events
384          * by poll logic and correct handling of state changes
385          * made by other threads is impossible in any case.
386          */
387
388         mask = 0;
389         if (sk->sk_err)
390                 mask = POLLERR;
391
392         /*
393          * POLLHUP is certainly not done right. But poll() doesn't
394          * have a notion of HUP in just one direction, and for a
395          * socket the read side is more interesting.
396          *
397          * Some poll() documentation says that POLLHUP is incompatible
398          * with the POLLOUT/POLLWR flags, so somebody should check this
399          * all. But careful, it tends to be safer to return too many
400          * bits than too few, and you can easily break real applications
401          * if you don't tell them that something has hung up!
402          *
403          * Check-me.
404          *
405          * Check number 1. POLLHUP is _UNMASKABLE_ event (see UNIX98 and
406          * our fs/select.c). It means that after we received EOF,
407          * poll always returns immediately, making impossible poll() on write()
408          * in state CLOSE_WAIT. One solution is evident --- to set POLLHUP
409          * if and only if shutdown has been made in both directions.
410          * Actually, it is interesting to look how Solaris and DUX
411          * solve this dilemma. I would prefer, if POLLHUP were maskable,
412          * then we could set it on SND_SHUTDOWN. BTW examples given
413          * in Stevens' books assume exactly this behaviour, it explains
414          * why POLLHUP is incompatible with POLLOUT.    --ANK
415          *
416          * NOTE. Check for TCP_CLOSE is added. The goal is to prevent
417          * blocking on fresh not-connected or disconnected socket. --ANK
418          */
419         if (sk->sk_shutdown == SHUTDOWN_MASK || sk->sk_state == TCP_CLOSE)
420                 mask |= POLLHUP;
421         if (sk->sk_shutdown & RCV_SHUTDOWN)
422                 mask |= POLLIN | POLLRDNORM | POLLRDHUP;
423
424         /* Connected? */
425         if ((1 << sk->sk_state) & ~(TCPF_SYN_SENT | TCPF_SYN_RECV)) {
426                 int target = sock_rcvlowat(sk, 0, INT_MAX);
427
428                 if (tp->urg_seq == tp->copied_seq &&
429                     !sock_flag(sk, SOCK_URGINLINE) &&
430                     tp->urg_data)
431                         target++;
432
433                 /* Potential race condition. If read of tp below will
434                  * escape above sk->sk_state, we can be illegally awaken
435                  * in SYN_* states. */
436                 if (tp->rcv_nxt - tp->copied_seq >= target)
437                         mask |= POLLIN | POLLRDNORM;
438
439                 if (!(sk->sk_shutdown & SEND_SHUTDOWN)) {
440                         if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk)) {
441                                 mask |= POLLOUT | POLLWRNORM;
442                         } else {  /* send SIGIO later */
443                                 set_bit(SOCK_ASYNC_NOSPACE,
444                                         &sk->sk_socket->flags);
445                                 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
446
447                                 /* Race breaker. If space is freed after
448                                  * wspace test but before the flags are set,
449                                  * IO signal will be lost.
450                                  */
451                                 if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk))
452                                         mask |= POLLOUT | POLLWRNORM;
453                         }
454                 }
455
456                 if (tp->urg_data & TCP_URG_VALID)
457                         mask |= POLLPRI;
458         }
459         return mask;
460 }
461 EXPORT_SYMBOL(tcp_poll);
462
463 int tcp_ioctl(struct sock *sk, int cmd, unsigned long arg)
464 {
465         struct tcp_sock *tp = tcp_sk(sk);
466         int answ;
467
468         switch (cmd) {
469         case SIOCINQ:
470                 if (sk->sk_state == TCP_LISTEN)
471                         return -EINVAL;
472
473                 lock_sock(sk);
474                 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
475                         answ = 0;
476                 else if (sock_flag(sk, SOCK_URGINLINE) ||
477                          !tp->urg_data ||
478                          before(tp->urg_seq, tp->copied_seq) ||
479                          !before(tp->urg_seq, tp->rcv_nxt)) {
480                         struct sk_buff *skb;
481
482                         answ = tp->rcv_nxt - tp->copied_seq;
483
484                         /* Subtract 1, if FIN is in queue. */
485                         skb = skb_peek_tail(&sk->sk_receive_queue);
486                         if (answ && skb)
487                                 answ -= tcp_hdr(skb)->fin;
488                 } else
489                         answ = tp->urg_seq - tp->copied_seq;
490                 release_sock(sk);
491                 break;
492         case SIOCATMARK:
493                 answ = tp->urg_data && tp->urg_seq == tp->copied_seq;
494                 break;
495         case SIOCOUTQ:
496                 if (sk->sk_state == TCP_LISTEN)
497                         return -EINVAL;
498
499                 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
500                         answ = 0;
501                 else
502                         answ = tp->write_seq - tp->snd_una;
503                 break;
504         default:
505                 return -ENOIOCTLCMD;
506         }
507
508         return put_user(answ, (int __user *)arg);
509 }
510 EXPORT_SYMBOL(tcp_ioctl);
511
512 static inline void tcp_mark_push(struct tcp_sock *tp, struct sk_buff *skb)
513 {
514         TCP_SKB_CB(skb)->flags |= TCPHDR_PSH;
515         tp->pushed_seq = tp->write_seq;
516 }
517
518 static inline int forced_push(struct tcp_sock *tp)
519 {
520         return after(tp->write_seq, tp->pushed_seq + (tp->max_window >> 1));
521 }
522
523 static inline void skb_entail(struct sock *sk, struct sk_buff *skb)
524 {
525         struct tcp_sock *tp = tcp_sk(sk);
526         struct tcp_skb_cb *tcb = TCP_SKB_CB(skb);
527
528         skb->csum    = 0;
529         tcb->seq     = tcb->end_seq = tp->write_seq;
530         tcb->flags   = TCPHDR_ACK;
531         tcb->sacked  = 0;
532         skb_header_release(skb);
533         tcp_add_write_queue_tail(sk, skb);
534         sk->sk_wmem_queued += skb->truesize;
535         sk_mem_charge(sk, skb->truesize);
536         if (tp->nonagle & TCP_NAGLE_PUSH)
537                 tp->nonagle &= ~TCP_NAGLE_PUSH;
538 }
539
540 static inline void tcp_mark_urg(struct tcp_sock *tp, int flags)
541 {
542         if (flags & MSG_OOB)
543                 tp->snd_up = tp->write_seq;
544 }
545
546 static inline void tcp_push(struct sock *sk, int flags, int mss_now,
547                             int nonagle)
548 {
549         if (tcp_send_head(sk)) {
550                 struct tcp_sock *tp = tcp_sk(sk);
551
552                 if (!(flags & MSG_MORE) || forced_push(tp))
553                         tcp_mark_push(tp, tcp_write_queue_tail(sk));
554
555                 tcp_mark_urg(tp, flags);
556                 __tcp_push_pending_frames(sk, mss_now,
557                                           (flags & MSG_MORE) ? TCP_NAGLE_CORK : nonagle);
558         }
559 }
560
561 static int tcp_splice_data_recv(read_descriptor_t *rd_desc, struct sk_buff *skb,
562                                 unsigned int offset, size_t len)
563 {
564         struct tcp_splice_state *tss = rd_desc->arg.data;
565         int ret;
566
567         ret = skb_splice_bits(skb, offset, tss->pipe, min(rd_desc->count, len),
568                               tss->flags);
569         if (ret > 0)
570                 rd_desc->count -= ret;
571         return ret;
572 }
573
574 static int __tcp_splice_read(struct sock *sk, struct tcp_splice_state *tss)
575 {
576         /* Store TCP splice context information in read_descriptor_t. */
577         read_descriptor_t rd_desc = {
578                 .arg.data = tss,
579                 .count    = tss->len,
580         };
581
582         return tcp_read_sock(sk, &rd_desc, tcp_splice_data_recv);
583 }
584
585 /**
586  *  tcp_splice_read - splice data from TCP socket to a pipe
587  * @sock:       socket to splice from
588  * @ppos:       position (not valid)
589  * @pipe:       pipe to splice to
590  * @len:        number of bytes to splice
591  * @flags:      splice modifier flags
592  *
593  * Description:
594  *    Will read pages from given socket and fill them into a pipe.
595  *
596  **/
597 ssize_t tcp_splice_read(struct socket *sock, loff_t *ppos,
598                         struct pipe_inode_info *pipe, size_t len,
599                         unsigned int flags)
600 {
601         struct sock *sk = sock->sk;
602         struct tcp_splice_state tss = {
603                 .pipe = pipe,
604                 .len = len,
605                 .flags = flags,
606         };
607         long timeo;
608         ssize_t spliced;
609         int ret;
610
611         sock_rps_record_flow(sk);
612         /*
613          * We can't seek on a socket input
614          */
615         if (unlikely(*ppos))
616                 return -ESPIPE;
617
618         ret = spliced = 0;
619
620         lock_sock(sk);
621
622         timeo = sock_rcvtimeo(sk, sock->file->f_flags & O_NONBLOCK);
623         while (tss.len) {
624                 ret = __tcp_splice_read(sk, &tss);
625                 if (ret < 0)
626                         break;
627                 else if (!ret) {
628                         if (spliced)
629                                 break;
630                         if (sock_flag(sk, SOCK_DONE))
631                                 break;
632                         if (sk->sk_err) {
633                                 ret = sock_error(sk);
634                                 break;
635                         }
636                         if (sk->sk_shutdown & RCV_SHUTDOWN)
637                                 break;
638                         if (sk->sk_state == TCP_CLOSE) {
639                                 /*
640                                  * This occurs when user tries to read
641                                  * from never connected socket.
642                                  */
643                                 if (!sock_flag(sk, SOCK_DONE))
644                                         ret = -ENOTCONN;
645                                 break;
646                         }
647                         if (!timeo) {
648                                 ret = -EAGAIN;
649                                 break;
650                         }
651                         sk_wait_data(sk, &timeo);
652                         if (signal_pending(current)) {
653                                 ret = sock_intr_errno(timeo);
654                                 break;
655                         }
656                         continue;
657                 }
658                 tss.len -= ret;
659                 spliced += ret;
660
661                 if (!timeo)
662                         break;
663                 release_sock(sk);
664                 lock_sock(sk);
665
666                 if (sk->sk_err || sk->sk_state == TCP_CLOSE ||
667                     (sk->sk_shutdown & RCV_SHUTDOWN) ||
668                     signal_pending(current))
669                         break;
670         }
671
672         release_sock(sk);
673
674         if (spliced)
675                 return spliced;
676
677         return ret;
678 }
679 EXPORT_SYMBOL(tcp_splice_read);
680
681 struct sk_buff *sk_stream_alloc_skb(struct sock *sk, int size, gfp_t gfp)
682 {
683         struct sk_buff *skb;
684
685         /* The TCP header must be at least 32-bit aligned.  */
686         size = ALIGN(size, 4);
687
688         skb = alloc_skb_fclone(size + sk->sk_prot->max_header, gfp);
689         if (skb) {
690                 if (sk_wmem_schedule(sk, skb->truesize)) {
691                         /*
692                          * Make sure that we have exactly size bytes
693                          * available to the caller, no more, no less.
694                          */
695                         skb_reserve(skb, skb_tailroom(skb) - size);
696                         return skb;
697                 }
698                 __kfree_skb(skb);
699         } else {
700                 sk->sk_prot->enter_memory_pressure(sk);
701                 sk_stream_moderate_sndbuf(sk);
702         }
703         return NULL;
704 }
705
706 static unsigned int tcp_xmit_size_goal(struct sock *sk, u32 mss_now,
707                                        int large_allowed)
708 {
709         struct tcp_sock *tp = tcp_sk(sk);
710         u32 xmit_size_goal, old_size_goal;
711
712         xmit_size_goal = mss_now;
713
714         if (large_allowed && sk_can_gso(sk)) {
715                 xmit_size_goal = ((sk->sk_gso_max_size - 1) -
716                                   inet_csk(sk)->icsk_af_ops->net_header_len -
717                                   inet_csk(sk)->icsk_ext_hdr_len -
718                                   tp->tcp_header_len);
719
720                 xmit_size_goal = tcp_bound_to_half_wnd(tp, xmit_size_goal);
721
722                 /* We try hard to avoid divides here */
723                 old_size_goal = tp->xmit_size_goal_segs * mss_now;
724
725                 if (likely(old_size_goal <= xmit_size_goal &&
726                            old_size_goal + mss_now > xmit_size_goal)) {
727                         xmit_size_goal = old_size_goal;
728                 } else {
729                         tp->xmit_size_goal_segs = xmit_size_goal / mss_now;
730                         xmit_size_goal = tp->xmit_size_goal_segs * mss_now;
731                 }
732         }
733
734         return max(xmit_size_goal, mss_now);
735 }
736
737 static int tcp_send_mss(struct sock *sk, int *size_goal, int flags)
738 {
739         int mss_now;
740
741         mss_now = tcp_current_mss(sk);
742         *size_goal = tcp_xmit_size_goal(sk, mss_now, !(flags & MSG_OOB));
743
744         return mss_now;
745 }
746
747 static ssize_t do_tcp_sendpages(struct sock *sk, struct page **pages, int poffset,
748                          size_t psize, int flags)
749 {
750         struct tcp_sock *tp = tcp_sk(sk);
751         int mss_now, size_goal;
752         int err;
753         ssize_t copied;
754         long timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
755
756         /* Wait for a connection to finish. */
757         if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT))
758                 if ((err = sk_stream_wait_connect(sk, &timeo)) != 0)
759                         goto out_err;
760
761         clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
762
763         mss_now = tcp_send_mss(sk, &size_goal, flags);
764         copied = 0;
765
766         err = -EPIPE;
767         if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
768                 goto out_err;
769
770         while (psize > 0) {
771                 struct sk_buff *skb = tcp_write_queue_tail(sk);
772                 struct page *page = pages[poffset / PAGE_SIZE];
773                 int copy, i, can_coalesce;
774                 int offset = poffset % PAGE_SIZE;
775                 int size = min_t(size_t, psize, PAGE_SIZE - offset);
776
777                 if (!tcp_send_head(sk) || (copy = size_goal - skb->len) <= 0) {
778 new_segment:
779                         if (!sk_stream_memory_free(sk))
780                                 goto wait_for_sndbuf;
781
782                         skb = sk_stream_alloc_skb(sk, 0, sk->sk_allocation);
783                         if (!skb)
784                                 goto wait_for_memory;
785
786                         skb_entail(sk, skb);
787                         copy = size_goal;
788                 }
789
790                 if (copy > size)
791                         copy = size;
792
793                 i = skb_shinfo(skb)->nr_frags;
794                 can_coalesce = skb_can_coalesce(skb, i, page, offset);
795                 if (!can_coalesce && i >= MAX_SKB_FRAGS) {
796                         tcp_mark_push(tp, skb);
797                         goto new_segment;
798                 }
799                 if (!sk_wmem_schedule(sk, copy))
800                         goto wait_for_memory;
801
802                 if (can_coalesce) {
803                         skb_shinfo(skb)->frags[i - 1].size += copy;
804                 } else {
805                         get_page(page);
806                         skb_fill_page_desc(skb, i, page, offset, copy);
807                 }
808
809                 skb->len += copy;
810                 skb->data_len += copy;
811                 skb->truesize += copy;
812                 sk->sk_wmem_queued += copy;
813                 sk_mem_charge(sk, copy);
814                 skb->ip_summed = CHECKSUM_PARTIAL;
815                 tp->write_seq += copy;
816                 TCP_SKB_CB(skb)->end_seq += copy;
817                 skb_shinfo(skb)->gso_segs = 0;
818
819                 if (!copied)
820                         TCP_SKB_CB(skb)->flags &= ~TCPHDR_PSH;
821
822                 copied += copy;
823                 poffset += copy;
824                 if (!(psize -= copy))
825                         goto out;
826
827                 if (skb->len < size_goal || (flags & MSG_OOB))
828                         continue;
829
830                 if (forced_push(tp)) {
831                         tcp_mark_push(tp, skb);
832                         __tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH);
833                 } else if (skb == tcp_send_head(sk))
834                         tcp_push_one(sk, mss_now);
835                 continue;
836
837 wait_for_sndbuf:
838                 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
839 wait_for_memory:
840                 if (copied)
841                         tcp_push(sk, flags & ~MSG_MORE, mss_now, TCP_NAGLE_PUSH);
842
843                 if ((err = sk_stream_wait_memory(sk, &timeo)) != 0)
844                         goto do_error;
845
846                 mss_now = tcp_send_mss(sk, &size_goal, flags);
847         }
848
849 out:
850         if (copied)
851                 tcp_push(sk, flags, mss_now, tp->nonagle);
852         return copied;
853
854 do_error:
855         if (copied)
856                 goto out;
857 out_err:
858         return sk_stream_error(sk, flags, err);
859 }
860
861 int tcp_sendpage(struct sock *sk, struct page *page, int offset,
862                  size_t size, int flags)
863 {
864         ssize_t res;
865
866         if (!(sk->sk_route_caps & NETIF_F_SG) ||
867             !(sk->sk_route_caps & NETIF_F_ALL_CSUM))
868                 return sock_no_sendpage(sk->sk_socket, page, offset, size,
869                                         flags);
870
871         lock_sock(sk);
872         TCP_CHECK_TIMER(sk);
873         res = do_tcp_sendpages(sk, &page, offset, size, flags);
874         TCP_CHECK_TIMER(sk);
875         release_sock(sk);
876         return res;
877 }
878 EXPORT_SYMBOL(tcp_sendpage);
879
880 #define TCP_PAGE(sk)    (sk->sk_sndmsg_page)
881 #define TCP_OFF(sk)     (sk->sk_sndmsg_off)
882
883 static inline int select_size(struct sock *sk, int sg)
884 {
885         struct tcp_sock *tp = tcp_sk(sk);
886         int tmp = tp->mss_cache;
887
888         if (sg) {
889                 if (sk_can_gso(sk))
890                         tmp = 0;
891                 else {
892                         int pgbreak = SKB_MAX_HEAD(MAX_TCP_HEADER);
893
894                         if (tmp >= pgbreak &&
895                             tmp <= pgbreak + (MAX_SKB_FRAGS - 1) * PAGE_SIZE)
896                                 tmp = pgbreak;
897                 }
898         }
899
900         return tmp;
901 }
902
903 int tcp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
904                 size_t size)
905 {
906         struct iovec *iov;
907         struct tcp_sock *tp = tcp_sk(sk);
908         struct sk_buff *skb;
909         int iovlen, flags;
910         int mss_now, size_goal;
911         int sg, err, copied;
912         long timeo;
913
914         lock_sock(sk);
915         TCP_CHECK_TIMER(sk);
916
917         flags = msg->msg_flags;
918         timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
919
920         /* Wait for a connection to finish. */
921         if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT))
922                 if ((err = sk_stream_wait_connect(sk, &timeo)) != 0)
923                         goto out_err;
924
925         /* This should be in poll */
926         clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
927
928         mss_now = tcp_send_mss(sk, &size_goal, flags);
929
930         /* Ok commence sending. */
931         iovlen = msg->msg_iovlen;
932         iov = msg->msg_iov;
933         copied = 0;
934
935         err = -EPIPE;
936         if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
937                 goto out_err;
938
939         sg = sk->sk_route_caps & NETIF_F_SG;
940
941         while (--iovlen >= 0) {
942                 int seglen = iov->iov_len;
943                 unsigned char __user *from = iov->iov_base;
944
945                 iov++;
946
947                 while (seglen > 0) {
948                         int copy = 0;
949                         int max = size_goal;
950
951                         skb = tcp_write_queue_tail(sk);
952                         if (tcp_send_head(sk)) {
953                                 if (skb->ip_summed == CHECKSUM_NONE)
954                                         max = mss_now;
955                                 copy = max - skb->len;
956                         }
957
958                         if (copy <= 0) {
959 new_segment:
960                                 /* Allocate new segment. If the interface is SG,
961                                  * allocate skb fitting to single page.
962                                  */
963                                 if (!sk_stream_memory_free(sk))
964                                         goto wait_for_sndbuf;
965
966                                 skb = sk_stream_alloc_skb(sk,
967                                                           select_size(sk, sg),
968                                                           sk->sk_allocation);
969                                 if (!skb)
970                                         goto wait_for_memory;
971
972                                 /*
973                                  * Check whether we can use HW checksum.
974                                  */
975                                 if (sk->sk_route_caps & NETIF_F_ALL_CSUM)
976                                         skb->ip_summed = CHECKSUM_PARTIAL;
977
978                                 skb_entail(sk, skb);
979                                 copy = size_goal;
980                                 max = size_goal;
981                         }
982
983                         /* Try to append data to the end of skb. */
984                         if (copy > seglen)
985                                 copy = seglen;
986
987                         /* Where to copy to? */
988                         if (skb_tailroom(skb) > 0) {
989                                 /* We have some space in skb head. Superb! */
990                                 if (copy > skb_tailroom(skb))
991                                         copy = skb_tailroom(skb);
992                                 if ((err = skb_add_data(skb, from, copy)) != 0)
993                                         goto do_fault;
994                         } else {
995                                 int merge = 0;
996                                 int i = skb_shinfo(skb)->nr_frags;
997                                 struct page *page = TCP_PAGE(sk);
998                                 int off = TCP_OFF(sk);
999
1000                                 if (skb_can_coalesce(skb, i, page, off) &&
1001                                     off != PAGE_SIZE) {
1002                                         /* We can extend the last page
1003                                          * fragment. */
1004                                         merge = 1;
1005                                 } else if (i == MAX_SKB_FRAGS || !sg) {
1006                                         /* Need to add new fragment and cannot
1007                                          * do this because interface is non-SG,
1008                                          * or because all the page slots are
1009                                          * busy. */
1010                                         tcp_mark_push(tp, skb);
1011                                         goto new_segment;
1012                                 } else if (page) {
1013                                         if (off == PAGE_SIZE) {
1014                                                 put_page(page);
1015                                                 TCP_PAGE(sk) = page = NULL;
1016                                                 off = 0;
1017                                         }
1018                                 } else
1019                                         off = 0;
1020
1021                                 if (copy > PAGE_SIZE - off)
1022                                         copy = PAGE_SIZE - off;
1023
1024                                 if (!sk_wmem_schedule(sk, copy))
1025                                         goto wait_for_memory;
1026
1027                                 if (!page) {
1028                                         /* Allocate new cache page. */
1029                                         if (!(page = sk_stream_alloc_page(sk)))
1030                                                 goto wait_for_memory;
1031                                 }
1032
1033                                 /* Time to copy data. We are close to
1034                                  * the end! */
1035                                 err = skb_copy_to_page(sk, from, skb, page,
1036                                                        off, copy);
1037                                 if (err) {
1038                                         /* If this page was new, give it to the
1039                                          * socket so it does not get leaked.
1040                                          */
1041                                         if (!TCP_PAGE(sk)) {
1042                                                 TCP_PAGE(sk) = page;
1043                                                 TCP_OFF(sk) = 0;
1044                                         }
1045                                         goto do_error;
1046                                 }
1047
1048                                 /* Update the skb. */
1049                                 if (merge) {
1050                                         skb_shinfo(skb)->frags[i - 1].size +=
1051                                                                         copy;
1052                                 } else {
1053                                         skb_fill_page_desc(skb, i, page, off, copy);
1054                                         if (TCP_PAGE(sk)) {
1055                                                 get_page(page);
1056                                         } else if (off + copy < PAGE_SIZE) {
1057                                                 get_page(page);
1058                                                 TCP_PAGE(sk) = page;
1059                                         }
1060                                 }
1061
1062                                 TCP_OFF(sk) = off + copy;
1063                         }
1064
1065                         if (!copied)
1066                                 TCP_SKB_CB(skb)->flags &= ~TCPHDR_PSH;
1067
1068                         tp->write_seq += copy;
1069                         TCP_SKB_CB(skb)->end_seq += copy;
1070                         skb_shinfo(skb)->gso_segs = 0;
1071
1072                         from += copy;
1073                         copied += copy;
1074                         if ((seglen -= copy) == 0 && iovlen == 0)
1075                                 goto out;
1076
1077                         if (skb->len < max || (flags & MSG_OOB))
1078                                 continue;
1079
1080                         if (forced_push(tp)) {
1081                                 tcp_mark_push(tp, skb);
1082                                 __tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH);
1083                         } else if (skb == tcp_send_head(sk))
1084                                 tcp_push_one(sk, mss_now);
1085                         continue;
1086
1087 wait_for_sndbuf:
1088                         set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
1089 wait_for_memory:
1090                         if (copied)
1091                                 tcp_push(sk, flags & ~MSG_MORE, mss_now, TCP_NAGLE_PUSH);
1092
1093                         if ((err = sk_stream_wait_memory(sk, &timeo)) != 0)
1094                                 goto do_error;
1095
1096                         mss_now = tcp_send_mss(sk, &size_goal, flags);
1097                 }
1098         }
1099
1100 out:
1101         if (copied)
1102                 tcp_push(sk, flags, mss_now, tp->nonagle);
1103         TCP_CHECK_TIMER(sk);
1104         release_sock(sk);
1105         return copied;
1106
1107 do_fault:
1108         if (!skb->len) {
1109                 tcp_unlink_write_queue(skb, sk);
1110                 /* It is the one place in all of TCP, except connection
1111                  * reset, where we can be unlinking the send_head.
1112                  */
1113                 tcp_check_send_head(sk, skb);
1114                 sk_wmem_free_skb(sk, skb);
1115         }
1116
1117 do_error:
1118         if (copied)
1119                 goto out;
1120 out_err:
1121         err = sk_stream_error(sk, flags, err);
1122         TCP_CHECK_TIMER(sk);
1123         release_sock(sk);
1124         return err;
1125 }
1126 EXPORT_SYMBOL(tcp_sendmsg);
1127
1128 /*
1129  *      Handle reading urgent data. BSD has very simple semantics for
1130  *      this, no blocking and very strange errors 8)
1131  */
1132
1133 static int tcp_recv_urg(struct sock *sk, struct msghdr *msg, int len, int flags)
1134 {
1135         struct tcp_sock *tp = tcp_sk(sk);
1136
1137         /* No URG data to read. */
1138         if (sock_flag(sk, SOCK_URGINLINE) || !tp->urg_data ||
1139             tp->urg_data == TCP_URG_READ)
1140                 return -EINVAL; /* Yes this is right ! */
1141
1142         if (sk->sk_state == TCP_CLOSE && !sock_flag(sk, SOCK_DONE))
1143                 return -ENOTCONN;
1144
1145         if (tp->urg_data & TCP_URG_VALID) {
1146                 int err = 0;
1147                 char c = tp->urg_data;
1148
1149                 if (!(flags & MSG_PEEK))
1150                         tp->urg_data = TCP_URG_READ;
1151
1152                 /* Read urgent data. */
1153                 msg->msg_flags |= MSG_OOB;
1154
1155                 if (len > 0) {
1156                         if (!(flags & MSG_TRUNC))
1157                                 err = memcpy_toiovec(msg->msg_iov, &c, 1);
1158                         len = 1;
1159                 } else
1160                         msg->msg_flags |= MSG_TRUNC;
1161
1162                 return err ? -EFAULT : len;
1163         }
1164
1165         if (sk->sk_state == TCP_CLOSE || (sk->sk_shutdown & RCV_SHUTDOWN))
1166                 return 0;
1167
1168         /* Fixed the recv(..., MSG_OOB) behaviour.  BSD docs and
1169          * the available implementations agree in this case:
1170          * this call should never block, independent of the
1171          * blocking state of the socket.
1172          * Mike <pall@rz.uni-karlsruhe.de>
1173          */
1174         return -EAGAIN;
1175 }
1176
1177 /* Clean up the receive buffer for full frames taken by the user,
1178  * then send an ACK if necessary.  COPIED is the number of bytes
1179  * tcp_recvmsg has given to the user so far, it speeds up the
1180  * calculation of whether or not we must ACK for the sake of
1181  * a window update.
1182  */
1183 void tcp_cleanup_rbuf(struct sock *sk, int copied)
1184 {
1185         struct tcp_sock *tp = tcp_sk(sk);
1186         int time_to_ack = 0;
1187
1188 #if TCP_DEBUG
1189         struct sk_buff *skb = skb_peek(&sk->sk_receive_queue);
1190
1191         WARN(skb && !before(tp->copied_seq, TCP_SKB_CB(skb)->end_seq),
1192              KERN_INFO "cleanup rbuf bug: copied %X seq %X rcvnxt %X\n",
1193              tp->copied_seq, TCP_SKB_CB(skb)->end_seq, tp->rcv_nxt);
1194 #endif
1195
1196         if (inet_csk_ack_scheduled(sk)) {
1197                 const struct inet_connection_sock *icsk = inet_csk(sk);
1198                    /* Delayed ACKs frequently hit locked sockets during bulk
1199                     * receive. */
1200                 if (icsk->icsk_ack.blocked ||
1201                     /* Once-per-two-segments ACK was not sent by tcp_input.c */
1202                     tp->rcv_nxt - tp->rcv_wup > icsk->icsk_ack.rcv_mss ||
1203                     /*
1204                      * If this read emptied read buffer, we send ACK, if
1205                      * connection is not bidirectional, user drained
1206                      * receive buffer and there was a small segment
1207                      * in queue.
1208                      */
1209                     (copied > 0 &&
1210                      ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED2) ||
1211                       ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED) &&
1212                        !icsk->icsk_ack.pingpong)) &&
1213                       !atomic_read(&sk->sk_rmem_alloc)))
1214                         time_to_ack = 1;
1215         }
1216
1217         /* We send an ACK if we can now advertise a non-zero window
1218          * which has been raised "significantly".
1219          *
1220          * Even if window raised up to infinity, do not send window open ACK
1221          * in states, where we will not receive more. It is useless.
1222          */
1223         if (copied > 0 && !time_to_ack && !(sk->sk_shutdown & RCV_SHUTDOWN)) {
1224                 __u32 rcv_window_now = tcp_receive_window(tp);
1225
1226                 /* Optimize, __tcp_select_window() is not cheap. */
1227                 if (2*rcv_window_now <= tp->window_clamp) {
1228                         __u32 new_window = __tcp_select_window(sk);
1229
1230                         /* Send ACK now, if this read freed lots of space
1231                          * in our buffer. Certainly, new_window is new window.
1232                          * We can advertise it now, if it is not less than current one.
1233                          * "Lots" means "at least twice" here.
1234                          */
1235                         if (new_window && new_window >= 2 * rcv_window_now)
1236                                 time_to_ack = 1;
1237                 }
1238         }
1239         if (time_to_ack)
1240                 tcp_send_ack(sk);
1241 }
1242
1243 static void tcp_prequeue_process(struct sock *sk)
1244 {
1245         struct sk_buff *skb;
1246         struct tcp_sock *tp = tcp_sk(sk);
1247
1248         NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPPREQUEUED);
1249
1250         /* RX process wants to run with disabled BHs, though it is not
1251          * necessary */
1252         local_bh_disable();
1253         while ((skb = __skb_dequeue(&tp->ucopy.prequeue)) != NULL)
1254                 sk_backlog_rcv(sk, skb);
1255         local_bh_enable();
1256
1257         /* Clear memory counter. */
1258         tp->ucopy.memory = 0;
1259 }
1260
1261 #ifdef CONFIG_NET_DMA
1262 static void tcp_service_net_dma(struct sock *sk, bool wait)
1263 {
1264         dma_cookie_t done, used;
1265         dma_cookie_t last_issued;
1266         struct tcp_sock *tp = tcp_sk(sk);
1267
1268         if (!tp->ucopy.dma_chan)
1269                 return;
1270
1271         last_issued = tp->ucopy.dma_cookie;
1272         dma_async_memcpy_issue_pending(tp->ucopy.dma_chan);
1273
1274         do {
1275                 if (dma_async_memcpy_complete(tp->ucopy.dma_chan,
1276                                               last_issued, &done,
1277                                               &used) == DMA_SUCCESS) {
1278                         /* Safe to free early-copied skbs now */
1279                         __skb_queue_purge(&sk->sk_async_wait_queue);
1280                         break;
1281                 } else {
1282                         struct sk_buff *skb;
1283                         while ((skb = skb_peek(&sk->sk_async_wait_queue)) &&
1284                                (dma_async_is_complete(skb->dma_cookie, done,
1285                                                       used) == DMA_SUCCESS)) {
1286                                 __skb_dequeue(&sk->sk_async_wait_queue);
1287                                 kfree_skb(skb);
1288                         }
1289                 }
1290         } while (wait);
1291 }
1292 #endif
1293
1294 static inline struct sk_buff *tcp_recv_skb(struct sock *sk, u32 seq, u32 *off)
1295 {
1296         struct sk_buff *skb;
1297         u32 offset;
1298
1299         skb_queue_walk(&sk->sk_receive_queue, skb) {
1300                 offset = seq - TCP_SKB_CB(skb)->seq;
1301                 if (tcp_hdr(skb)->syn)
1302                         offset--;
1303                 if (offset < skb->len || tcp_hdr(skb)->fin) {
1304                         *off = offset;
1305                         return skb;
1306                 }
1307         }
1308         return NULL;
1309 }
1310
1311 /*
1312  * This routine provides an alternative to tcp_recvmsg() for routines
1313  * that would like to handle copying from skbuffs directly in 'sendfile'
1314  * fashion.
1315  * Note:
1316  *      - It is assumed that the socket was locked by the caller.
1317  *      - The routine does not block.
1318  *      - At present, there is no support for reading OOB data
1319  *        or for 'peeking' the socket using this routine
1320  *        (although both would be easy to implement).
1321  */
1322 int tcp_read_sock(struct sock *sk, read_descriptor_t *desc,
1323                   sk_read_actor_t recv_actor)
1324 {
1325         struct sk_buff *skb;
1326         struct tcp_sock *tp = tcp_sk(sk);
1327         u32 seq = tp->copied_seq;
1328         u32 offset;
1329         int copied = 0;
1330
1331         if (sk->sk_state == TCP_LISTEN)
1332                 return -ENOTCONN;
1333         while ((skb = tcp_recv_skb(sk, seq, &offset)) != NULL) {
1334                 if (offset < skb->len) {
1335                         int used;
1336                         size_t len;
1337
1338                         len = skb->len - offset;
1339                         /* Stop reading if we hit a patch of urgent data */
1340                         if (tp->urg_data) {
1341                                 u32 urg_offset = tp->urg_seq - seq;
1342                                 if (urg_offset < len)
1343                                         len = urg_offset;
1344                                 if (!len)
1345                                         break;
1346                         }
1347                         used = recv_actor(desc, skb, offset, len);
1348                         if (used < 0) {
1349                                 if (!copied)
1350                                         copied = used;
1351                                 break;
1352                         } else if (used <= len) {
1353                                 seq += used;
1354                                 copied += used;
1355                                 offset += used;
1356                         }
1357                         /*
1358                          * If recv_actor drops the lock (e.g. TCP splice
1359                          * receive) the skb pointer might be invalid when
1360                          * getting here: tcp_collapse might have deleted it
1361                          * while aggregating skbs from the socket queue.
1362                          */
1363                         skb = tcp_recv_skb(sk, seq-1, &offset);
1364                         if (!skb || (offset+1 != skb->len))
1365                                 break;
1366                 }
1367                 if (tcp_hdr(skb)->fin) {
1368                         sk_eat_skb(sk, skb, 0);
1369                         ++seq;
1370                         break;
1371                 }
1372                 sk_eat_skb(sk, skb, 0);
1373                 if (!desc->count)
1374                         break;
1375                 tp->copied_seq = seq;
1376         }
1377         tp->copied_seq = seq;
1378
1379         tcp_rcv_space_adjust(sk);
1380
1381         /* Clean up data we have read: This will do ACK frames. */
1382         if (copied > 0)
1383                 tcp_cleanup_rbuf(sk, copied);
1384         return copied;
1385 }
1386 EXPORT_SYMBOL(tcp_read_sock);
1387
1388 /*
1389  *      This routine copies from a sock struct into the user buffer.
1390  *
1391  *      Technical note: in 2.3 we work on _locked_ socket, so that
1392  *      tricks with *seq access order and skb->users are not required.
1393  *      Probably, code can be easily improved even more.
1394  */
1395
1396 int tcp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
1397                 size_t len, int nonblock, int flags, int *addr_len)
1398 {
1399         struct tcp_sock *tp = tcp_sk(sk);
1400         int copied = 0;
1401         u32 peek_seq;
1402         u32 *seq;
1403         unsigned long used;
1404         int err;
1405         int target;             /* Read at least this many bytes */
1406         long timeo;
1407         struct task_struct *user_recv = NULL;
1408         int copied_early = 0;
1409         struct sk_buff *skb;
1410         u32 urg_hole = 0;
1411
1412         lock_sock(sk);
1413
1414         TCP_CHECK_TIMER(sk);
1415
1416         err = -ENOTCONN;
1417         if (sk->sk_state == TCP_LISTEN)
1418                 goto out;
1419
1420         timeo = sock_rcvtimeo(sk, nonblock);
1421
1422         /* Urgent data needs to be handled specially. */
1423         if (flags & MSG_OOB)
1424                 goto recv_urg;
1425
1426         seq = &tp->copied_seq;
1427         if (flags & MSG_PEEK) {
1428                 peek_seq = tp->copied_seq;
1429                 seq = &peek_seq;
1430         }
1431
1432         target = sock_rcvlowat(sk, flags & MSG_WAITALL, len);
1433
1434 #ifdef CONFIG_NET_DMA
1435         tp->ucopy.dma_chan = NULL;
1436         preempt_disable();
1437         skb = skb_peek_tail(&sk->sk_receive_queue);
1438         {
1439                 int available = 0;
1440
1441                 if (skb)
1442                         available = TCP_SKB_CB(skb)->seq + skb->len - (*seq);
1443                 if ((available < target) &&
1444                     (len > sysctl_tcp_dma_copybreak) && !(flags & MSG_PEEK) &&
1445                     !sysctl_tcp_low_latency &&
1446                     dma_find_channel(DMA_MEMCPY)) {
1447                         preempt_enable_no_resched();
1448                         tp->ucopy.pinned_list =
1449                                         dma_pin_iovec_pages(msg->msg_iov, len);
1450                 } else {
1451                         preempt_enable_no_resched();
1452                 }
1453         }
1454 #endif
1455
1456         do {
1457                 u32 offset;
1458
1459                 /* Are we at urgent data? Stop if we have read anything or have SIGURG pending. */
1460                 if (tp->urg_data && tp->urg_seq == *seq) {
1461                         if (copied)
1462                                 break;
1463                         if (signal_pending(current)) {
1464                                 copied = timeo ? sock_intr_errno(timeo) : -EAGAIN;
1465                                 break;
1466                         }
1467                 }
1468
1469                 /* Next get a buffer. */
1470
1471                 skb_queue_walk(&sk->sk_receive_queue, skb) {
1472                         /* Now that we have two receive queues this
1473                          * shouldn't happen.
1474                          */
1475                         if (WARN(before(*seq, TCP_SKB_CB(skb)->seq),
1476                              KERN_INFO "recvmsg bug: copied %X "
1477                                        "seq %X rcvnxt %X fl %X\n", *seq,
1478                                        TCP_SKB_CB(skb)->seq, tp->rcv_nxt,
1479                                        flags))
1480                                 break;
1481
1482                         offset = *seq - TCP_SKB_CB(skb)->seq;
1483                         if (tcp_hdr(skb)->syn)
1484                                 offset--;
1485                         if (offset < skb->len)
1486                                 goto found_ok_skb;
1487                         if (tcp_hdr(skb)->fin)
1488                                 goto found_fin_ok;
1489                         WARN(!(flags & MSG_PEEK), KERN_INFO "recvmsg bug 2: "
1490                                         "copied %X seq %X rcvnxt %X fl %X\n",
1491                                         *seq, TCP_SKB_CB(skb)->seq,
1492                                         tp->rcv_nxt, flags);
1493                 }
1494
1495                 /* Well, if we have backlog, try to process it now yet. */
1496
1497                 if (copied >= target && !sk->sk_backlog.tail)
1498                         break;
1499
1500                 if (copied) {
1501                         if (sk->sk_err ||
1502                             sk->sk_state == TCP_CLOSE ||
1503                             (sk->sk_shutdown & RCV_SHUTDOWN) ||
1504                             !timeo ||
1505                             signal_pending(current))
1506                                 break;
1507                 } else {
1508                         if (sock_flag(sk, SOCK_DONE))
1509                                 break;
1510
1511                         if (sk->sk_err) {
1512                                 copied = sock_error(sk);
1513                                 break;
1514                         }
1515
1516                         if (sk->sk_shutdown & RCV_SHUTDOWN)
1517                                 break;
1518
1519                         if (sk->sk_state == TCP_CLOSE) {
1520                                 if (!sock_flag(sk, SOCK_DONE)) {
1521                                         /* This occurs when user tries to read
1522                                          * from never connected socket.
1523                                          */
1524                                         copied = -ENOTCONN;
1525                                         break;
1526                                 }
1527                                 break;
1528                         }
1529
1530                         if (!timeo) {
1531                                 copied = -EAGAIN;
1532                                 break;
1533                         }
1534
1535                         if (signal_pending(current)) {
1536                                 copied = sock_intr_errno(timeo);
1537                                 break;
1538                         }
1539                 }
1540
1541                 tcp_cleanup_rbuf(sk, copied);
1542
1543                 if (!sysctl_tcp_low_latency && tp->ucopy.task == user_recv) {
1544                         /* Install new reader */
1545                         if (!user_recv && !(flags & (MSG_TRUNC | MSG_PEEK))) {
1546                                 user_recv = current;
1547                                 tp->ucopy.task = user_recv;
1548                                 tp->ucopy.iov = msg->msg_iov;
1549                         }
1550
1551                         tp->ucopy.len = len;
1552
1553                         WARN_ON(tp->copied_seq != tp->rcv_nxt &&
1554                                 !(flags & (MSG_PEEK | MSG_TRUNC)));
1555
1556                         /* Ugly... If prequeue is not empty, we have to
1557                          * process it before releasing socket, otherwise
1558                          * order will be broken at second iteration.
1559                          * More elegant solution is required!!!
1560                          *
1561                          * Look: we have the following (pseudo)queues:
1562                          *
1563                          * 1. packets in flight
1564                          * 2. backlog
1565                          * 3. prequeue
1566                          * 4. receive_queue
1567                          *
1568                          * Each queue can be processed only if the next ones
1569                          * are empty. At this point we have empty receive_queue.
1570                          * But prequeue _can_ be not empty after 2nd iteration,
1571                          * when we jumped to start of loop because backlog
1572                          * processing added something to receive_queue.
1573                          * We cannot release_sock(), because backlog contains
1574                          * packets arrived _after_ prequeued ones.
1575                          *
1576                          * Shortly, algorithm is clear --- to process all
1577                          * the queues in order. We could make it more directly,
1578                          * requeueing packets from backlog to prequeue, if
1579                          * is not empty. It is more elegant, but eats cycles,
1580                          * unfortunately.
1581                          */
1582                         if (!skb_queue_empty(&tp->ucopy.prequeue))
1583                                 goto do_prequeue;
1584
1585                         /* __ Set realtime policy in scheduler __ */
1586                 }
1587
1588 #ifdef CONFIG_NET_DMA
1589                 if (tp->ucopy.dma_chan)
1590                         dma_async_memcpy_issue_pending(tp->ucopy.dma_chan);
1591 #endif
1592                 if (copied >= target) {
1593                         /* Do not sleep, just process backlog. */
1594                         release_sock(sk);
1595                         lock_sock(sk);
1596                 } else
1597                         sk_wait_data(sk, &timeo);
1598
1599 #ifdef CONFIG_NET_DMA
1600                 tcp_service_net_dma(sk, false);  /* Don't block */
1601                 tp->ucopy.wakeup = 0;
1602 #endif
1603
1604                 if (user_recv) {
1605                         int chunk;
1606
1607                         /* __ Restore normal policy in scheduler __ */
1608
1609                         if ((chunk = len - tp->ucopy.len) != 0) {
1610                                 NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMBACKLOG, chunk);
1611                                 len -= chunk;
1612                                 copied += chunk;
1613                         }
1614
1615                         if (tp->rcv_nxt == tp->copied_seq &&
1616                             !skb_queue_empty(&tp->ucopy.prequeue)) {
1617 do_prequeue:
1618                                 tcp_prequeue_process(sk);
1619
1620                                 if ((chunk = len - tp->ucopy.len) != 0) {
1621                                         NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
1622                                         len -= chunk;
1623                                         copied += chunk;
1624                                 }
1625                         }
1626                 }
1627                 if ((flags & MSG_PEEK) &&
1628                     (peek_seq - copied - urg_hole != tp->copied_seq)) {
1629                         if (net_ratelimit())
1630                                 printk(KERN_DEBUG "TCP(%s:%d): Application bug, race in MSG_PEEK.\n",
1631                                        current->comm, task_pid_nr(current));
1632                         peek_seq = tp->copied_seq;
1633                 }
1634                 continue;
1635
1636         found_ok_skb:
1637                 /* Ok so how much can we use? */
1638                 used = skb->len - offset;
1639                 if (len < used)
1640                         used = len;
1641
1642                 /* Do we have urgent data here? */
1643                 if (tp->urg_data) {
1644                         u32 urg_offset = tp->urg_seq - *seq;
1645                         if (urg_offset < used) {
1646                                 if (!urg_offset) {
1647                                         if (!sock_flag(sk, SOCK_URGINLINE)) {
1648                                                 ++*seq;
1649                                                 urg_hole++;
1650                                                 offset++;
1651                                                 used--;
1652                                                 if (!used)
1653                                                         goto skip_copy;
1654                                         }
1655                                 } else
1656                                         used = urg_offset;
1657                         }
1658                 }
1659
1660                 if (!(flags & MSG_TRUNC)) {
1661 #ifdef CONFIG_NET_DMA
1662                         if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list)
1663                                 tp->ucopy.dma_chan = dma_find_channel(DMA_MEMCPY);
1664
1665                         if (tp->ucopy.dma_chan) {
1666                                 tp->ucopy.dma_cookie = dma_skb_copy_datagram_iovec(
1667                                         tp->ucopy.dma_chan, skb, offset,
1668                                         msg->msg_iov, used,
1669                                         tp->ucopy.pinned_list);
1670
1671                                 if (tp->ucopy.dma_cookie < 0) {
1672
1673                                         printk(KERN_ALERT "dma_cookie < 0\n");
1674
1675                                         /* Exception. Bailout! */
1676                                         if (!copied)
1677                                                 copied = -EFAULT;
1678                                         break;
1679                                 }
1680
1681                                 dma_async_memcpy_issue_pending(tp->ucopy.dma_chan);
1682
1683                                 if ((offset + used) == skb->len)
1684                                         copied_early = 1;
1685
1686                         } else
1687 #endif
1688                         {
1689                                 err = skb_copy_datagram_iovec(skb, offset,
1690                                                 msg->msg_iov, used);
1691                                 if (err) {
1692                                         /* Exception. Bailout! */
1693                                         if (!copied)
1694                                                 copied = -EFAULT;
1695                                         break;
1696                                 }
1697                         }
1698                 }
1699
1700                 *seq += used;
1701                 copied += used;
1702                 len -= used;
1703
1704                 tcp_rcv_space_adjust(sk);
1705
1706 skip_copy:
1707                 if (tp->urg_data && after(tp->copied_seq, tp->urg_seq)) {
1708                         tp->urg_data = 0;
1709                         tcp_fast_path_check(sk);
1710                 }
1711                 if (used + offset < skb->len)
1712                         continue;
1713
1714                 if (tcp_hdr(skb)->fin)
1715                         goto found_fin_ok;
1716                 if (!(flags & MSG_PEEK)) {
1717                         sk_eat_skb(sk, skb, copied_early);
1718                         copied_early = 0;
1719                 }
1720                 continue;
1721
1722         found_fin_ok:
1723                 /* Process the FIN. */
1724                 ++*seq;
1725                 if (!(flags & MSG_PEEK)) {
1726                         sk_eat_skb(sk, skb, copied_early);
1727                         copied_early = 0;
1728                 }
1729                 break;
1730         } while (len > 0);
1731
1732         if (user_recv) {
1733                 if (!skb_queue_empty(&tp->ucopy.prequeue)) {
1734                         int chunk;
1735
1736                         tp->ucopy.len = copied > 0 ? len : 0;
1737
1738                         tcp_prequeue_process(sk);
1739
1740                         if (copied > 0 && (chunk = len - tp->ucopy.len) != 0) {
1741                                 NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
1742                                 len -= chunk;
1743                                 copied += chunk;
1744                         }
1745                 }
1746
1747                 tp->ucopy.task = NULL;
1748                 tp->ucopy.len = 0;
1749         }
1750
1751 #ifdef CONFIG_NET_DMA
1752         tcp_service_net_dma(sk, true);  /* Wait for queue to drain */
1753         tp->ucopy.dma_chan = NULL;
1754
1755         if (tp->ucopy.pinned_list) {
1756                 dma_unpin_iovec_pages(tp->ucopy.pinned_list);
1757                 tp->ucopy.pinned_list = NULL;
1758         }
1759 #endif
1760
1761         /* According to UNIX98, msg_name/msg_namelen are ignored
1762          * on connected socket. I was just happy when found this 8) --ANK
1763          */
1764
1765         /* Clean up data we have read: This will do ACK frames. */
1766         tcp_cleanup_rbuf(sk, copied);
1767
1768         TCP_CHECK_TIMER(sk);
1769         release_sock(sk);
1770         return copied;
1771
1772 out:
1773         TCP_CHECK_TIMER(sk);
1774         release_sock(sk);
1775         return err;
1776
1777 recv_urg:
1778         err = tcp_recv_urg(sk, msg, len, flags);
1779         goto out;
1780 }
1781 EXPORT_SYMBOL(tcp_recvmsg);
1782
1783 void tcp_set_state(struct sock *sk, int state)
1784 {
1785         int oldstate = sk->sk_state;
1786
1787         switch (state) {
1788         case TCP_ESTABLISHED:
1789                 if (oldstate != TCP_ESTABLISHED)
1790                         TCP_INC_STATS(sock_net(sk), TCP_MIB_CURRESTAB);
1791                 break;
1792
1793         case TCP_CLOSE:
1794                 if (oldstate == TCP_CLOSE_WAIT || oldstate == TCP_ESTABLISHED)
1795                         TCP_INC_STATS(sock_net(sk), TCP_MIB_ESTABRESETS);
1796
1797                 sk->sk_prot->unhash(sk);
1798                 if (inet_csk(sk)->icsk_bind_hash &&
1799                     !(sk->sk_userlocks & SOCK_BINDPORT_LOCK))
1800                         inet_put_port(sk);
1801                 /* fall through */
1802         default:
1803                 if (oldstate == TCP_ESTABLISHED)
1804                         TCP_DEC_STATS(sock_net(sk), TCP_MIB_CURRESTAB);
1805         }
1806
1807         /* Change state AFTER socket is unhashed to avoid closed
1808          * socket sitting in hash tables.
1809          */
1810         sk->sk_state = state;
1811
1812 #ifdef STATE_TRACE
1813         SOCK_DEBUG(sk, "TCP sk=%p, State %s -> %s\n", sk, statename[oldstate], statename[state]);
1814 #endif
1815 }
1816 EXPORT_SYMBOL_GPL(tcp_set_state);
1817
1818 /*
1819  *      State processing on a close. This implements the state shift for
1820  *      sending our FIN frame. Note that we only send a FIN for some
1821  *      states. A shutdown() may have already sent the FIN, or we may be
1822  *      closed.
1823  */
1824
1825 static const unsigned char new_state[16] = {
1826   /* current state:        new state:      action:      */
1827   /* (Invalid)          */ TCP_CLOSE,
1828   /* TCP_ESTABLISHED    */ TCP_FIN_WAIT1 | TCP_ACTION_FIN,
1829   /* TCP_SYN_SENT       */ TCP_CLOSE,
1830   /* TCP_SYN_RECV       */ TCP_FIN_WAIT1 | TCP_ACTION_FIN,
1831   /* TCP_FIN_WAIT1      */ TCP_FIN_WAIT1,
1832   /* TCP_FIN_WAIT2      */ TCP_FIN_WAIT2,
1833   /* TCP_TIME_WAIT      */ TCP_CLOSE,
1834   /* TCP_CLOSE          */ TCP_CLOSE,
1835   /* TCP_CLOSE_WAIT     */ TCP_LAST_ACK  | TCP_ACTION_FIN,
1836   /* TCP_LAST_ACK       */ TCP_LAST_ACK,
1837   /* TCP_LISTEN         */ TCP_CLOSE,
1838   /* TCP_CLOSING        */ TCP_CLOSING,
1839 };
1840
1841 static int tcp_close_state(struct sock *sk)
1842 {
1843         int next = (int)new_state[sk->sk_state];
1844         int ns = next & TCP_STATE_MASK;
1845
1846         tcp_set_state(sk, ns);
1847
1848         return next & TCP_ACTION_FIN;
1849 }
1850
1851 /*
1852  *      Shutdown the sending side of a connection. Much like close except
1853  *      that we don't receive shut down or sock_set_flag(sk, SOCK_DEAD).
1854  */
1855
1856 void tcp_shutdown(struct sock *sk, int how)
1857 {
1858         /*      We need to grab some memory, and put together a FIN,
1859          *      and then put it into the queue to be sent.
1860          *              Tim MacKenzie(tym@dibbler.cs.monash.edu.au) 4 Dec '92.
1861          */
1862         if (!(how & SEND_SHUTDOWN))
1863                 return;
1864
1865         /* If we've already sent a FIN, or it's a closed state, skip this. */
1866         if ((1 << sk->sk_state) &
1867             (TCPF_ESTABLISHED | TCPF_SYN_SENT |
1868              TCPF_SYN_RECV | TCPF_CLOSE_WAIT)) {
1869                 /* Clear out any half completed packets.  FIN if needed. */
1870                 if (tcp_close_state(sk))
1871                         tcp_send_fin(sk);
1872         }
1873 }
1874 EXPORT_SYMBOL(tcp_shutdown);
1875
1876 void tcp_close(struct sock *sk, long timeout)
1877 {
1878         struct sk_buff *skb;
1879         int data_was_unread = 0;
1880         int state;
1881
1882         lock_sock(sk);
1883         sk->sk_shutdown = SHUTDOWN_MASK;
1884
1885         if (sk->sk_state == TCP_LISTEN) {
1886                 tcp_set_state(sk, TCP_CLOSE);
1887
1888                 /* Special case. */
1889                 inet_csk_listen_stop(sk);
1890
1891                 goto adjudge_to_death;
1892         }
1893
1894         /*  We need to flush the recv. buffs.  We do this only on the
1895          *  descriptor close, not protocol-sourced closes, because the
1896          *  reader process may not have drained the data yet!
1897          */
1898         while ((skb = __skb_dequeue(&sk->sk_receive_queue)) != NULL) {
1899                 u32 len = TCP_SKB_CB(skb)->end_seq - TCP_SKB_CB(skb)->seq -
1900                           tcp_hdr(skb)->fin;
1901                 data_was_unread += len;
1902                 __kfree_skb(skb);
1903         }
1904
1905         sk_mem_reclaim(sk);
1906
1907         /* If socket has been already reset (e.g. in tcp_reset()) - kill it. */
1908         if (sk->sk_state == TCP_CLOSE)
1909                 goto adjudge_to_death;
1910
1911         /* As outlined in RFC 2525, section 2.17, we send a RST here because
1912          * data was lost. To witness the awful effects of the old behavior of
1913          * always doing a FIN, run an older 2.1.x kernel or 2.0.x, start a bulk
1914          * GET in an FTP client, suspend the process, wait for the client to
1915          * advertise a zero window, then kill -9 the FTP client, wheee...
1916          * Note: timeout is always zero in such a case.
1917          */
1918         if (data_was_unread) {
1919                 /* Unread data was tossed, zap the connection. */
1920                 NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPABORTONCLOSE);
1921                 tcp_set_state(sk, TCP_CLOSE);
1922                 tcp_send_active_reset(sk, sk->sk_allocation);
1923         } else if (sock_flag(sk, SOCK_LINGER) && !sk->sk_lingertime) {
1924                 /* Check zero linger _after_ checking for unread data. */
1925                 sk->sk_prot->disconnect(sk, 0);
1926                 NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPABORTONDATA);
1927         } else if (tcp_close_state(sk)) {
1928                 /* We FIN if the application ate all the data before
1929                  * zapping the connection.
1930                  */
1931
1932                 /* RED-PEN. Formally speaking, we have broken TCP state
1933                  * machine. State transitions:
1934                  *
1935                  * TCP_ESTABLISHED -> TCP_FIN_WAIT1
1936                  * TCP_SYN_RECV -> TCP_FIN_WAIT1 (forget it, it's impossible)
1937                  * TCP_CLOSE_WAIT -> TCP_LAST_ACK
1938                  *
1939                  * are legal only when FIN has been sent (i.e. in window),
1940                  * rather than queued out of window. Purists blame.
1941                  *
1942                  * F.e. "RFC state" is ESTABLISHED,
1943                  * if Linux state is FIN-WAIT-1, but FIN is still not sent.
1944                  *
1945                  * The visible declinations are that sometimes
1946                  * we enter time-wait state, when it is not required really
1947                  * (harmless), do not send active resets, when they are
1948                  * required by specs (TCP_ESTABLISHED, TCP_CLOSE_WAIT, when
1949                  * they look as CLOSING or LAST_ACK for Linux)
1950                  * Probably, I missed some more holelets.
1951                  *                                              --ANK
1952                  */
1953                 tcp_send_fin(sk);
1954         }
1955
1956         sk_stream_wait_close(sk, timeout);
1957
1958 adjudge_to_death:
1959         state = sk->sk_state;
1960         sock_hold(sk);
1961         sock_orphan(sk);
1962
1963         /* It is the last release_sock in its life. It will remove backlog. */
1964         release_sock(sk);
1965
1966
1967         /* Now socket is owned by kernel and we acquire BH lock
1968            to finish close. No need to check for user refs.
1969          */
1970         local_bh_disable();
1971         bh_lock_sock(sk);
1972         WARN_ON(sock_owned_by_user(sk));
1973
1974         percpu_counter_inc(sk->sk_prot->orphan_count);
1975
1976         /* Have we already been destroyed by a softirq or backlog? */
1977         if (state != TCP_CLOSE && sk->sk_state == TCP_CLOSE)
1978                 goto out;
1979
1980         /*      This is a (useful) BSD violating of the RFC. There is a
1981          *      problem with TCP as specified in that the other end could
1982          *      keep a socket open forever with no application left this end.
1983          *      We use a 3 minute timeout (about the same as BSD) then kill
1984          *      our end. If they send after that then tough - BUT: long enough
1985          *      that we won't make the old 4*rto = almost no time - whoops
1986          *      reset mistake.
1987          *
1988          *      Nope, it was not mistake. It is really desired behaviour
1989          *      f.e. on http servers, when such sockets are useless, but
1990          *      consume significant resources. Let's do it with special
1991          *      linger2 option.                                 --ANK
1992          */
1993
1994         if (sk->sk_state == TCP_FIN_WAIT2) {
1995                 struct tcp_sock *tp = tcp_sk(sk);
1996                 if (tp->linger2 < 0) {
1997                         tcp_set_state(sk, TCP_CLOSE);
1998                         tcp_send_active_reset(sk, GFP_ATOMIC);
1999                         NET_INC_STATS_BH(sock_net(sk),
2000                                         LINUX_MIB_TCPABORTONLINGER);
2001                 } else {
2002                         const int tmo = tcp_fin_time(sk);
2003
2004                         if (tmo > TCP_TIMEWAIT_LEN) {
2005                                 inet_csk_reset_keepalive_timer(sk,
2006                                                 tmo - TCP_TIMEWAIT_LEN);
2007                         } else {
2008                                 tcp_time_wait(sk, TCP_FIN_WAIT2, tmo);
2009                                 goto out;
2010                         }
2011                 }
2012         }
2013         if (sk->sk_state != TCP_CLOSE) {
2014                 int orphan_count = percpu_counter_read_positive(
2015                                                 sk->sk_prot->orphan_count);
2016
2017                 sk_mem_reclaim(sk);
2018                 if (tcp_too_many_orphans(sk, orphan_count)) {
2019                         if (net_ratelimit())
2020                                 printk(KERN_INFO "TCP: too many of orphaned "
2021                                        "sockets\n");
2022                         tcp_set_state(sk, TCP_CLOSE);
2023                         tcp_send_active_reset(sk, GFP_ATOMIC);
2024                         NET_INC_STATS_BH(sock_net(sk),
2025                                         LINUX_MIB_TCPABORTONMEMORY);
2026                 }
2027         }
2028
2029         if (sk->sk_state == TCP_CLOSE)
2030                 inet_csk_destroy_sock(sk);
2031         /* Otherwise, socket is reprieved until protocol close. */
2032
2033 out:
2034         bh_unlock_sock(sk);
2035         local_bh_enable();
2036         sock_put(sk);
2037 }
2038 EXPORT_SYMBOL(tcp_close);
2039
2040 /* These states need RST on ABORT according to RFC793 */
2041
2042 static inline int tcp_need_reset(int state)
2043 {
2044         return (1 << state) &
2045                (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT | TCPF_FIN_WAIT1 |
2046                 TCPF_FIN_WAIT2 | TCPF_SYN_RECV);
2047 }
2048
2049 int tcp_disconnect(struct sock *sk, int flags)
2050 {
2051         struct inet_sock *inet = inet_sk(sk);
2052         struct inet_connection_sock *icsk = inet_csk(sk);
2053         struct tcp_sock *tp = tcp_sk(sk);
2054         int err = 0;
2055         int old_state = sk->sk_state;
2056
2057         if (old_state != TCP_CLOSE)
2058                 tcp_set_state(sk, TCP_CLOSE);
2059
2060         /* ABORT function of RFC793 */
2061         if (old_state == TCP_LISTEN) {
2062                 inet_csk_listen_stop(sk);
2063         } else if (tcp_need_reset(old_state) ||
2064                    (tp->snd_nxt != tp->write_seq &&
2065                     (1 << old_state) & (TCPF_CLOSING | TCPF_LAST_ACK))) {
2066                 /* The last check adjusts for discrepancy of Linux wrt. RFC
2067                  * states
2068                  */
2069                 tcp_send_active_reset(sk, gfp_any());
2070                 sk->sk_err = ECONNRESET;
2071         } else if (old_state == TCP_SYN_SENT)
2072                 sk->sk_err = ECONNRESET;
2073
2074         tcp_clear_xmit_timers(sk);
2075         __skb_queue_purge(&sk->sk_receive_queue);
2076         tcp_write_queue_purge(sk);
2077         __skb_queue_purge(&tp->out_of_order_queue);
2078 #ifdef CONFIG_NET_DMA
2079         __skb_queue_purge(&sk->sk_async_wait_queue);
2080 #endif
2081
2082         inet->inet_dport = 0;
2083
2084         if (!(sk->sk_userlocks & SOCK_BINDADDR_LOCK))
2085                 inet_reset_saddr(sk);
2086
2087         sk->sk_shutdown = 0;
2088         sock_reset_flag(sk, SOCK_DONE);
2089         tp->srtt = 0;
2090         if ((tp->write_seq += tp->max_window + 2) == 0)
2091                 tp->write_seq = 1;
2092         icsk->icsk_backoff = 0;
2093         tp->snd_cwnd = 2;
2094         icsk->icsk_probes_out = 0;
2095         tp->packets_out = 0;
2096         tp->snd_ssthresh = TCP_INFINITE_SSTHRESH;
2097         tp->snd_cwnd_cnt = 0;
2098         tp->bytes_acked = 0;
2099         tp->window_clamp = 0;
2100         tcp_set_ca_state(sk, TCP_CA_Open);
2101         tcp_clear_retrans(tp);
2102         inet_csk_delack_init(sk);
2103         tcp_init_send_head(sk);
2104         memset(&tp->rx_opt, 0, sizeof(tp->rx_opt));
2105         __sk_dst_reset(sk);
2106
2107         WARN_ON(inet->inet_num && !icsk->icsk_bind_hash);
2108
2109         sk->sk_error_report(sk);
2110         return err;
2111 }
2112 EXPORT_SYMBOL(tcp_disconnect);
2113
2114 /*
2115  *      Socket option code for TCP.
2116  */
2117 static int do_tcp_setsockopt(struct sock *sk, int level,
2118                 int optname, char __user *optval, unsigned int optlen)
2119 {
2120         struct tcp_sock *tp = tcp_sk(sk);
2121         struct inet_connection_sock *icsk = inet_csk(sk);
2122         int val;
2123         int err = 0;
2124
2125         /* These are data/string values, all the others are ints */
2126         switch (optname) {
2127         case TCP_CONGESTION: {
2128                 char name[TCP_CA_NAME_MAX];
2129
2130                 if (optlen < 1)
2131                         return -EINVAL;
2132
2133                 val = strncpy_from_user(name, optval,
2134                                         min_t(long, TCP_CA_NAME_MAX-1, optlen));
2135                 if (val < 0)
2136                         return -EFAULT;
2137                 name[val] = 0;
2138
2139                 lock_sock(sk);
2140                 err = tcp_set_congestion_control(sk, name);
2141                 release_sock(sk);
2142                 return err;
2143         }
2144         case TCP_COOKIE_TRANSACTIONS: {
2145                 struct tcp_cookie_transactions ctd;
2146                 struct tcp_cookie_values *cvp = NULL;
2147
2148                 if (sizeof(ctd) > optlen)
2149                         return -EINVAL;
2150                 if (copy_from_user(&ctd, optval, sizeof(ctd)))
2151                         return -EFAULT;
2152
2153                 if (ctd.tcpct_used > sizeof(ctd.tcpct_value) ||
2154                     ctd.tcpct_s_data_desired > TCP_MSS_DESIRED)
2155                         return -EINVAL;
2156
2157                 if (ctd.tcpct_cookie_desired == 0) {
2158                         /* default to global value */
2159                 } else if ((0x1 & ctd.tcpct_cookie_desired) ||
2160                            ctd.tcpct_cookie_desired > TCP_COOKIE_MAX ||
2161                            ctd.tcpct_cookie_desired < TCP_COOKIE_MIN) {
2162                         return -EINVAL;
2163                 }
2164
2165                 if (TCP_COOKIE_OUT_NEVER & ctd.tcpct_flags) {
2166                         /* Supercedes all other values */
2167                         lock_sock(sk);
2168                         if (tp->cookie_values != NULL) {
2169                                 kref_put(&tp->cookie_values->kref,
2170                                          tcp_cookie_values_release);
2171                                 tp->cookie_values = NULL;
2172                         }
2173                         tp->rx_opt.cookie_in_always = 0; /* false */
2174                         tp->rx_opt.cookie_out_never = 1; /* true */
2175                         release_sock(sk);
2176                         return err;
2177                 }
2178
2179                 /* Allocate ancillary memory before locking.
2180                  */
2181                 if (ctd.tcpct_used > 0 ||
2182                     (tp->cookie_values == NULL &&
2183                      (sysctl_tcp_cookie_size > 0 ||
2184                       ctd.tcpct_cookie_desired > 0 ||
2185                       ctd.tcpct_s_data_desired > 0))) {
2186                         cvp = kzalloc(sizeof(*cvp) + ctd.tcpct_used,
2187                                       GFP_KERNEL);
2188                         if (cvp == NULL)
2189                                 return -ENOMEM;
2190
2191                         kref_init(&cvp->kref);
2192                 }
2193                 lock_sock(sk);
2194                 tp->rx_opt.cookie_in_always =
2195                         (TCP_COOKIE_IN_ALWAYS & ctd.tcpct_flags);
2196                 tp->rx_opt.cookie_out_never = 0; /* false */
2197
2198                 if (tp->cookie_values != NULL) {
2199                         if (cvp != NULL) {
2200                                 /* Changed values are recorded by a changed
2201                                  * pointer, ensuring the cookie will differ,
2202                                  * without separately hashing each value later.
2203                                  */
2204                                 kref_put(&tp->cookie_values->kref,
2205                                          tcp_cookie_values_release);
2206                         } else {
2207                                 cvp = tp->cookie_values;
2208                         }
2209                 }
2210
2211                 if (cvp != NULL) {
2212                         cvp->cookie_desired = ctd.tcpct_cookie_desired;
2213
2214                         if (ctd.tcpct_used > 0) {
2215                                 memcpy(cvp->s_data_payload, ctd.tcpct_value,
2216                                        ctd.tcpct_used);
2217                                 cvp->s_data_desired = ctd.tcpct_used;
2218                                 cvp->s_data_constant = 1; /* true */
2219                         } else {
2220                                 /* No constant payload data. */
2221                                 cvp->s_data_desired = ctd.tcpct_s_data_desired;
2222                                 cvp->s_data_constant = 0; /* false */
2223                         }
2224
2225                         tp->cookie_values = cvp;
2226                 }
2227                 release_sock(sk);
2228                 return err;
2229         }
2230         default:
2231                 /* fallthru */
2232                 break;
2233         }
2234
2235         if (optlen < sizeof(int))
2236                 return -EINVAL;
2237
2238         if (get_user(val, (int __user *)optval))
2239                 return -EFAULT;
2240
2241         lock_sock(sk);
2242
2243         switch (optname) {
2244         case TCP_MAXSEG:
2245                 /* Values greater than interface MTU won't take effect. However
2246                  * at the point when this call is done we typically don't yet
2247                  * know which interface is going to be used */
2248                 if (val < 8 || val > MAX_TCP_WINDOW) {
2249                         err = -EINVAL;
2250                         break;
2251                 }
2252                 tp->rx_opt.user_mss = val;
2253                 break;
2254
2255         case TCP_NODELAY:
2256                 if (val) {
2257                         /* TCP_NODELAY is weaker than TCP_CORK, so that
2258                          * this option on corked socket is remembered, but
2259                          * it is not activated until cork is cleared.
2260                          *
2261                          * However, when TCP_NODELAY is set we make
2262                          * an explicit push, which overrides even TCP_CORK
2263                          * for currently queued segments.
2264                          */
2265                         tp->nonagle |= TCP_NAGLE_OFF|TCP_NAGLE_PUSH;
2266                         tcp_push_pending_frames(sk);
2267                 } else {
2268                         tp->nonagle &= ~TCP_NAGLE_OFF;
2269                 }
2270                 break;
2271
2272         case TCP_THIN_LINEAR_TIMEOUTS:
2273                 if (val < 0 || val > 1)
2274                         err = -EINVAL;
2275                 else
2276                         tp->thin_lto = val;
2277                 break;
2278
2279         case TCP_THIN_DUPACK:
2280                 if (val < 0 || val > 1)
2281                         err = -EINVAL;
2282                 else
2283                         tp->thin_dupack = val;
2284                 break;
2285
2286         case TCP_CORK:
2287                 /* When set indicates to always queue non-full frames.
2288                  * Later the user clears this option and we transmit
2289                  * any pending partial frames in the queue.  This is
2290                  * meant to be used alongside sendfile() to get properly
2291                  * filled frames when the user (for example) must write
2292                  * out headers with a write() call first and then use
2293                  * sendfile to send out the data parts.
2294                  *
2295                  * TCP_CORK can be set together with TCP_NODELAY and it is
2296                  * stronger than TCP_NODELAY.
2297                  */
2298                 if (val) {
2299                         tp->nonagle |= TCP_NAGLE_CORK;
2300                 } else {
2301                         tp->nonagle &= ~TCP_NAGLE_CORK;
2302                         if (tp->nonagle&TCP_NAGLE_OFF)
2303                                 tp->nonagle |= TCP_NAGLE_PUSH;
2304                         tcp_push_pending_frames(sk);
2305                 }
2306                 break;
2307
2308         case TCP_KEEPIDLE:
2309                 if (val < 1 || val > MAX_TCP_KEEPIDLE)
2310                         err = -EINVAL;
2311                 else {
2312                         tp->keepalive_time = val * HZ;
2313                         if (sock_flag(sk, SOCK_KEEPOPEN) &&
2314                             !((1 << sk->sk_state) &
2315                               (TCPF_CLOSE | TCPF_LISTEN))) {
2316                                 u32 elapsed = keepalive_time_elapsed(tp);
2317                                 if (tp->keepalive_time > elapsed)
2318                                         elapsed = tp->keepalive_time - elapsed;
2319                                 else
2320                                         elapsed = 0;
2321                                 inet_csk_reset_keepalive_timer(sk, elapsed);
2322                         }
2323                 }
2324                 break;
2325         case TCP_KEEPINTVL:
2326                 if (val < 1 || val > MAX_TCP_KEEPINTVL)
2327                         err = -EINVAL;
2328                 else
2329                         tp->keepalive_intvl = val * HZ;
2330                 break;
2331         case TCP_KEEPCNT:
2332                 if (val < 1 || val > MAX_TCP_KEEPCNT)
2333                         err = -EINVAL;
2334                 else
2335                         tp->keepalive_probes = val;
2336                 break;
2337         case TCP_SYNCNT:
2338                 if (val < 1 || val > MAX_TCP_SYNCNT)
2339                         err = -EINVAL;
2340                 else
2341                         icsk->icsk_syn_retries = val;
2342                 break;
2343
2344         case TCP_LINGER2:
2345                 if (val < 0)
2346                         tp->linger2 = -1;
2347                 else if (val > sysctl_tcp_fin_timeout / HZ)
2348                         tp->linger2 = 0;
2349                 else
2350                         tp->linger2 = val * HZ;
2351                 break;
2352
2353         case TCP_DEFER_ACCEPT:
2354                 /* Translate value in seconds to number of retransmits */
2355                 icsk->icsk_accept_queue.rskq_defer_accept =
2356                         secs_to_retrans(val, TCP_TIMEOUT_INIT / HZ,
2357                                         TCP_RTO_MAX / HZ);
2358                 break;
2359
2360         case TCP_WINDOW_CLAMP:
2361                 if (!val) {
2362                         if (sk->sk_state != TCP_CLOSE) {
2363                                 err = -EINVAL;
2364                                 break;
2365                         }
2366                         tp->window_clamp = 0;
2367                 } else
2368                         tp->window_clamp = val < SOCK_MIN_RCVBUF / 2 ?
2369                                                 SOCK_MIN_RCVBUF / 2 : val;
2370                 break;
2371
2372         case TCP_QUICKACK:
2373                 if (!val) {
2374                         icsk->icsk_ack.pingpong = 1;
2375                 } else {
2376                         icsk->icsk_ack.pingpong = 0;
2377                         if ((1 << sk->sk_state) &
2378                             (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT) &&
2379                             inet_csk_ack_scheduled(sk)) {
2380                                 icsk->icsk_ack.pending |= ICSK_ACK_PUSHED;
2381                                 tcp_cleanup_rbuf(sk, 1);
2382                                 if (!(val & 1))
2383                                         icsk->icsk_ack.pingpong = 1;
2384                         }
2385                 }
2386                 break;
2387
2388 #ifdef CONFIG_TCP_MD5SIG
2389         case TCP_MD5SIG:
2390                 /* Read the IP->Key mappings from userspace */
2391                 err = tp->af_specific->md5_parse(sk, optval, optlen);
2392                 break;
2393 #endif
2394
2395         default:
2396                 err = -ENOPROTOOPT;
2397                 break;
2398         }
2399
2400         release_sock(sk);
2401         return err;
2402 }
2403
2404 int tcp_setsockopt(struct sock *sk, int level, int optname, char __user *optval,
2405                    unsigned int optlen)
2406 {
2407         struct inet_connection_sock *icsk = inet_csk(sk);
2408
2409         if (level != SOL_TCP)
2410                 return icsk->icsk_af_ops->setsockopt(sk, level, optname,
2411                                                      optval, optlen);
2412         return do_tcp_setsockopt(sk, level, optname, optval, optlen);
2413 }
2414 EXPORT_SYMBOL(tcp_setsockopt);
2415
2416 #ifdef CONFIG_COMPAT
2417 int compat_tcp_setsockopt(struct sock *sk, int level, int optname,
2418                           char __user *optval, unsigned int optlen)
2419 {
2420         if (level != SOL_TCP)
2421                 return inet_csk_compat_setsockopt(sk, level, optname,
2422                                                   optval, optlen);
2423         return do_tcp_setsockopt(sk, level, optname, optval, optlen);
2424 }
2425 EXPORT_SYMBOL(compat_tcp_setsockopt);
2426 #endif
2427
2428 /* Return information about state of tcp endpoint in API format. */
2429 void tcp_get_info(struct sock *sk, struct tcp_info *info)
2430 {
2431         struct tcp_sock *tp = tcp_sk(sk);
2432         const struct inet_connection_sock *icsk = inet_csk(sk);
2433         u32 now = tcp_time_stamp;
2434
2435         memset(info, 0, sizeof(*info));
2436
2437         info->tcpi_state = sk->sk_state;
2438         info->tcpi_ca_state = icsk->icsk_ca_state;
2439         info->tcpi_retransmits = icsk->icsk_retransmits;
2440         info->tcpi_probes = icsk->icsk_probes_out;
2441         info->tcpi_backoff = icsk->icsk_backoff;
2442
2443         if (tp->rx_opt.tstamp_ok)
2444                 info->tcpi_options |= TCPI_OPT_TIMESTAMPS;
2445         if (tcp_is_sack(tp))
2446                 info->tcpi_options |= TCPI_OPT_SACK;
2447         if (tp->rx_opt.wscale_ok) {
2448                 info->tcpi_options |= TCPI_OPT_WSCALE;
2449                 info->tcpi_snd_wscale = tp->rx_opt.snd_wscale;
2450                 info->tcpi_rcv_wscale = tp->rx_opt.rcv_wscale;
2451         }
2452
2453         if (tp->ecn_flags&TCP_ECN_OK)
2454                 info->tcpi_options |= TCPI_OPT_ECN;
2455
2456         info->tcpi_rto = jiffies_to_usecs(icsk->icsk_rto);
2457         info->tcpi_ato = jiffies_to_usecs(icsk->icsk_ack.ato);
2458         info->tcpi_snd_mss = tp->mss_cache;
2459         info->tcpi_rcv_mss = icsk->icsk_ack.rcv_mss;
2460
2461         if (sk->sk_state == TCP_LISTEN) {
2462                 info->tcpi_unacked = sk->sk_ack_backlog;
2463                 info->tcpi_sacked = sk->sk_max_ack_backlog;
2464         } else {
2465                 info->tcpi_unacked = tp->packets_out;
2466                 info->tcpi_sacked = tp->sacked_out;
2467         }
2468         info->tcpi_lost = tp->lost_out;
2469         info->tcpi_retrans = tp->retrans_out;
2470         info->tcpi_fackets = tp->fackets_out;
2471
2472         info->tcpi_last_data_sent = jiffies_to_msecs(now - tp->lsndtime);
2473         info->tcpi_last_data_recv = jiffies_to_msecs(now - icsk->icsk_ack.lrcvtime);
2474         info->tcpi_last_ack_recv = jiffies_to_msecs(now - tp->rcv_tstamp);
2475
2476         info->tcpi_pmtu = icsk->icsk_pmtu_cookie;
2477         info->tcpi_rcv_ssthresh = tp->rcv_ssthresh;
2478         info->tcpi_rtt = jiffies_to_usecs(tp->srtt)>>3;
2479         info->tcpi_rttvar = jiffies_to_usecs(tp->mdev)>>2;
2480         info->tcpi_snd_ssthresh = tp->snd_ssthresh;
2481         info->tcpi_snd_cwnd = tp->snd_cwnd;
2482         info->tcpi_advmss = tp->advmss;
2483         info->tcpi_reordering = tp->reordering;
2484
2485         info->tcpi_rcv_rtt = jiffies_to_usecs(tp->rcv_rtt_est.rtt)>>3;
2486         info->tcpi_rcv_space = tp->rcvq_space.space;
2487
2488         info->tcpi_total_retrans = tp->total_retrans;
2489 }
2490 EXPORT_SYMBOL_GPL(tcp_get_info);
2491
2492 static int do_tcp_getsockopt(struct sock *sk, int level,
2493                 int optname, char __user *optval, int __user *optlen)
2494 {
2495         struct inet_connection_sock *icsk = inet_csk(sk);
2496         struct tcp_sock *tp = tcp_sk(sk);
2497         int val, len;
2498
2499         if (get_user(len, optlen))
2500                 return -EFAULT;
2501
2502         len = min_t(unsigned int, len, sizeof(int));
2503
2504         if (len < 0)
2505                 return -EINVAL;
2506
2507         switch (optname) {
2508         case TCP_MAXSEG:
2509                 val = tp->mss_cache;
2510                 if (!val && ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN)))
2511                         val = tp->rx_opt.user_mss;
2512                 break;
2513         case TCP_NODELAY:
2514                 val = !!(tp->nonagle&TCP_NAGLE_OFF);
2515                 break;
2516         case TCP_CORK:
2517                 val = !!(tp->nonagle&TCP_NAGLE_CORK);
2518                 break;
2519         case TCP_KEEPIDLE:
2520                 val = keepalive_time_when(tp) / HZ;
2521                 break;
2522         case TCP_KEEPINTVL:
2523                 val = keepalive_intvl_when(tp) / HZ;
2524                 break;
2525         case TCP_KEEPCNT:
2526                 val = keepalive_probes(tp);
2527                 break;
2528         case TCP_SYNCNT:
2529                 val = icsk->icsk_syn_retries ? : sysctl_tcp_syn_retries;
2530                 break;
2531         case TCP_LINGER2:
2532                 val = tp->linger2;
2533                 if (val >= 0)
2534                         val = (val ? : sysctl_tcp_fin_timeout) / HZ;
2535                 break;
2536         case TCP_DEFER_ACCEPT:
2537                 val = retrans_to_secs(icsk->icsk_accept_queue.rskq_defer_accept,
2538                                       TCP_TIMEOUT_INIT / HZ, TCP_RTO_MAX / HZ);
2539                 break;
2540         case TCP_WINDOW_CLAMP:
2541                 val = tp->window_clamp;
2542                 break;
2543         case TCP_INFO: {
2544                 struct tcp_info info;
2545
2546                 if (get_user(len, optlen))
2547                         return -EFAULT;
2548
2549                 tcp_get_info(sk, &info);
2550
2551                 len = min_t(unsigned int, len, sizeof(info));
2552                 if (put_user(len, optlen))
2553                         return -EFAULT;
2554                 if (copy_to_user(optval, &info, len))
2555                         return -EFAULT;
2556                 return 0;
2557         }
2558         case TCP_QUICKACK:
2559                 val = !icsk->icsk_ack.pingpong;
2560                 break;
2561
2562         case TCP_CONGESTION:
2563                 if (get_user(len, optlen))
2564                         return -EFAULT;
2565                 len = min_t(unsigned int, len, TCP_CA_NAME_MAX);
2566                 if (put_user(len, optlen))
2567                         return -EFAULT;
2568                 if (copy_to_user(optval, icsk->icsk_ca_ops->name, len))
2569                         return -EFAULT;
2570                 return 0;
2571
2572         case TCP_COOKIE_TRANSACTIONS: {
2573                 struct tcp_cookie_transactions ctd;
2574                 struct tcp_cookie_values *cvp = tp->cookie_values;
2575
2576                 if (get_user(len, optlen))
2577                         return -EFAULT;
2578                 if (len < sizeof(ctd))
2579                         return -EINVAL;
2580
2581                 memset(&ctd, 0, sizeof(ctd));
2582                 ctd.tcpct_flags = (tp->rx_opt.cookie_in_always ?
2583                                    TCP_COOKIE_IN_ALWAYS : 0)
2584                                 | (tp->rx_opt.cookie_out_never ?
2585                                    TCP_COOKIE_OUT_NEVER : 0);
2586
2587                 if (cvp != NULL) {
2588                         ctd.tcpct_flags |= (cvp->s_data_in ?
2589                                             TCP_S_DATA_IN : 0)
2590                                          | (cvp->s_data_out ?
2591                                             TCP_S_DATA_OUT : 0);
2592
2593                         ctd.tcpct_cookie_desired = cvp->cookie_desired;
2594                         ctd.tcpct_s_data_desired = cvp->s_data_desired;
2595
2596                         memcpy(&ctd.tcpct_value[0], &cvp->cookie_pair[0],
2597                                cvp->cookie_pair_size);
2598                         ctd.tcpct_used = cvp->cookie_pair_size;
2599                 }
2600
2601                 if (put_user(sizeof(ctd), optlen))
2602                         return -EFAULT;
2603                 if (copy_to_user(optval, &ctd, sizeof(ctd)))
2604                         return -EFAULT;
2605                 return 0;
2606         }
2607         case TCP_THIN_LINEAR_TIMEOUTS:
2608                 val = tp->thin_lto;
2609                 break;
2610         case TCP_THIN_DUPACK:
2611                 val = tp->thin_dupack;
2612                 break;
2613         default:
2614                 return -ENOPROTOOPT;
2615         }
2616
2617         if (put_user(len, optlen))
2618                 return -EFAULT;
2619         if (copy_to_user(optval, &val, len))
2620                 return -EFAULT;
2621         return 0;
2622 }
2623
2624 int tcp_getsockopt(struct sock *sk, int level, int optname, char __user *optval,
2625                    int __user *optlen)
2626 {
2627         struct inet_connection_sock *icsk = inet_csk(sk);
2628
2629         if (level != SOL_TCP)
2630                 return icsk->icsk_af_ops->getsockopt(sk, level, optname,
2631                                                      optval, optlen);
2632         return do_tcp_getsockopt(sk, level, optname, optval, optlen);
2633 }
2634 EXPORT_SYMBOL(tcp_getsockopt);
2635
2636 #ifdef CONFIG_COMPAT
2637 int compat_tcp_getsockopt(struct sock *sk, int level, int optname,
2638                           char __user *optval, int __user *optlen)
2639 {
2640         if (level != SOL_TCP)
2641                 return inet_csk_compat_getsockopt(sk, level, optname,
2642                                                   optval, optlen);
2643         return do_tcp_getsockopt(sk, level, optname, optval, optlen);
2644 }
2645 EXPORT_SYMBOL(compat_tcp_getsockopt);
2646 #endif
2647
2648 struct sk_buff *tcp_tso_segment(struct sk_buff *skb, int features)
2649 {
2650         struct sk_buff *segs = ERR_PTR(-EINVAL);
2651         struct tcphdr *th;
2652         unsigned thlen;
2653         unsigned int seq;
2654         __be32 delta;
2655         unsigned int oldlen;
2656         unsigned int mss;
2657
2658         if (!pskb_may_pull(skb, sizeof(*th)))
2659                 goto out;
2660
2661         th = tcp_hdr(skb);
2662         thlen = th->doff * 4;
2663         if (thlen < sizeof(*th))
2664                 goto out;
2665
2666         if (!pskb_may_pull(skb, thlen))
2667                 goto out;
2668
2669         oldlen = (u16)~skb->len;
2670         __skb_pull(skb, thlen);
2671
2672         mss = skb_shinfo(skb)->gso_size;
2673         if (unlikely(skb->len <= mss))
2674                 goto out;
2675
2676         if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) {
2677                 /* Packet is from an untrusted source, reset gso_segs. */
2678                 int type = skb_shinfo(skb)->gso_type;
2679
2680                 if (unlikely(type &
2681                              ~(SKB_GSO_TCPV4 |
2682                                SKB_GSO_DODGY |
2683                                SKB_GSO_TCP_ECN |
2684                                SKB_GSO_TCPV6 |
2685                                0) ||
2686                              !(type & (SKB_GSO_TCPV4 | SKB_GSO_TCPV6))))
2687                         goto out;
2688
2689                 skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss);
2690
2691                 segs = NULL;
2692                 goto out;
2693         }
2694
2695         segs = skb_segment(skb, features);
2696         if (IS_ERR(segs))
2697                 goto out;
2698
2699         delta = htonl(oldlen + (thlen + mss));
2700
2701         skb = segs;
2702         th = tcp_hdr(skb);
2703         seq = ntohl(th->seq);
2704
2705         do {
2706                 th->fin = th->psh = 0;
2707
2708                 th->check = ~csum_fold((__force __wsum)((__force u32)th->check +
2709                                        (__force u32)delta));
2710                 if (skb->ip_summed != CHECKSUM_PARTIAL)
2711                         th->check =
2712                              csum_fold(csum_partial(skb_transport_header(skb),
2713                                                     thlen, skb->csum));
2714
2715                 seq += mss;
2716                 skb = skb->next;
2717                 th = tcp_hdr(skb);
2718
2719                 th->seq = htonl(seq);
2720                 th->cwr = 0;
2721         } while (skb->next);
2722
2723         delta = htonl(oldlen + (skb->tail - skb->transport_header) +
2724                       skb->data_len);
2725         th->check = ~csum_fold((__force __wsum)((__force u32)th->check +
2726                                 (__force u32)delta));
2727         if (skb->ip_summed != CHECKSUM_PARTIAL)
2728                 th->check = csum_fold(csum_partial(skb_transport_header(skb),
2729                                                    thlen, skb->csum));
2730
2731 out:
2732         return segs;
2733 }
2734 EXPORT_SYMBOL(tcp_tso_segment);
2735
2736 struct sk_buff **tcp_gro_receive(struct sk_buff **head, struct sk_buff *skb)
2737 {
2738         struct sk_buff **pp = NULL;
2739         struct sk_buff *p;
2740         struct tcphdr *th;
2741         struct tcphdr *th2;
2742         unsigned int len;
2743         unsigned int thlen;
2744         __be32 flags;
2745         unsigned int mss = 1;
2746         unsigned int hlen;
2747         unsigned int off;
2748         int flush = 1;
2749         int i;
2750
2751         off = skb_gro_offset(skb);
2752         hlen = off + sizeof(*th);
2753         th = skb_gro_header_fast(skb, off);
2754         if (skb_gro_header_hard(skb, hlen)) {
2755                 th = skb_gro_header_slow(skb, hlen, off);
2756                 if (unlikely(!th))
2757                         goto out;
2758         }
2759
2760         thlen = th->doff * 4;
2761         if (thlen < sizeof(*th))
2762                 goto out;
2763
2764         hlen = off + thlen;
2765         if (skb_gro_header_hard(skb, hlen)) {
2766                 th = skb_gro_header_slow(skb, hlen, off);
2767                 if (unlikely(!th))
2768                         goto out;
2769         }
2770
2771         skb_gro_pull(skb, thlen);
2772
2773         len = skb_gro_len(skb);
2774         flags = tcp_flag_word(th);
2775
2776         for (; (p = *head); head = &p->next) {
2777                 if (!NAPI_GRO_CB(p)->same_flow)
2778                         continue;
2779
2780                 th2 = tcp_hdr(p);
2781
2782                 if (*(u32 *)&th->source ^ *(u32 *)&th2->source) {
2783                         NAPI_GRO_CB(p)->same_flow = 0;
2784                         continue;
2785                 }
2786
2787                 goto found;
2788         }
2789
2790         goto out_check_final;
2791
2792 found:
2793         flush = NAPI_GRO_CB(p)->flush;
2794         flush |= (__force int)(flags & TCP_FLAG_CWR);
2795         flush |= (__force int)((flags ^ tcp_flag_word(th2)) &
2796                   ~(TCP_FLAG_CWR | TCP_FLAG_FIN | TCP_FLAG_PSH));
2797         flush |= (__force int)(th->ack_seq ^ th2->ack_seq);
2798         for (i = sizeof(*th); i < thlen; i += 4)
2799                 flush |= *(u32 *)((u8 *)th + i) ^
2800                          *(u32 *)((u8 *)th2 + i);
2801
2802         mss = skb_shinfo(p)->gso_size;
2803
2804         flush |= (len - 1) >= mss;
2805         flush |= (ntohl(th2->seq) + skb_gro_len(p)) ^ ntohl(th->seq);
2806
2807         if (flush || skb_gro_receive(head, skb)) {
2808                 mss = 1;
2809                 goto out_check_final;
2810         }
2811
2812         p = *head;
2813         th2 = tcp_hdr(p);
2814         tcp_flag_word(th2) |= flags & (TCP_FLAG_FIN | TCP_FLAG_PSH);
2815
2816 out_check_final:
2817         flush = len < mss;
2818         flush |= (__force int)(flags & (TCP_FLAG_URG | TCP_FLAG_PSH |
2819                                         TCP_FLAG_RST | TCP_FLAG_SYN |
2820                                         TCP_FLAG_FIN));
2821
2822         if (p && (!NAPI_GRO_CB(skb)->same_flow || flush))
2823                 pp = head;
2824
2825 out:
2826         NAPI_GRO_CB(skb)->flush |= flush;
2827
2828         return pp;
2829 }
2830 EXPORT_SYMBOL(tcp_gro_receive);
2831
2832 int tcp_gro_complete(struct sk_buff *skb)
2833 {
2834         struct tcphdr *th = tcp_hdr(skb);
2835
2836         skb->csum_start = skb_transport_header(skb) - skb->head;
2837         skb->csum_offset = offsetof(struct tcphdr, check);
2838         skb->ip_summed = CHECKSUM_PARTIAL;
2839
2840         skb_shinfo(skb)->gso_segs = NAPI_GRO_CB(skb)->count;
2841
2842         if (th->cwr)
2843                 skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
2844
2845         return 0;
2846 }
2847 EXPORT_SYMBOL(tcp_gro_complete);
2848
2849 #ifdef CONFIG_TCP_MD5SIG
2850 static unsigned long tcp_md5sig_users;
2851 static struct tcp_md5sig_pool * __percpu *tcp_md5sig_pool;
2852 static DEFINE_SPINLOCK(tcp_md5sig_pool_lock);
2853
2854 static void __tcp_free_md5sig_pool(struct tcp_md5sig_pool * __percpu *pool)
2855 {
2856         int cpu;
2857         for_each_possible_cpu(cpu) {
2858                 struct tcp_md5sig_pool *p = *per_cpu_ptr(pool, cpu);
2859                 if (p) {
2860                         if (p->md5_desc.tfm)
2861                                 crypto_free_hash(p->md5_desc.tfm);
2862                         kfree(p);
2863                 }
2864         }
2865         free_percpu(pool);
2866 }
2867
2868 void tcp_free_md5sig_pool(void)
2869 {
2870         struct tcp_md5sig_pool * __percpu *pool = NULL;
2871
2872         spin_lock_bh(&tcp_md5sig_pool_lock);
2873         if (--tcp_md5sig_users == 0) {
2874                 pool = tcp_md5sig_pool;
2875                 tcp_md5sig_pool = NULL;
2876         }
2877         spin_unlock_bh(&tcp_md5sig_pool_lock);
2878         if (pool)
2879                 __tcp_free_md5sig_pool(pool);
2880 }
2881 EXPORT_SYMBOL(tcp_free_md5sig_pool);
2882
2883 static struct tcp_md5sig_pool * __percpu *
2884 __tcp_alloc_md5sig_pool(struct sock *sk)
2885 {
2886         int cpu;
2887         struct tcp_md5sig_pool * __percpu *pool;
2888
2889         pool = alloc_percpu(struct tcp_md5sig_pool *);
2890         if (!pool)
2891                 return NULL;
2892
2893         for_each_possible_cpu(cpu) {
2894                 struct tcp_md5sig_pool *p;
2895                 struct crypto_hash *hash;
2896
2897                 p = kzalloc(sizeof(*p), sk->sk_allocation);
2898                 if (!p)
2899                         goto out_free;
2900                 *per_cpu_ptr(pool, cpu) = p;
2901
2902                 hash = crypto_alloc_hash("md5", 0, CRYPTO_ALG_ASYNC);
2903                 if (!hash || IS_ERR(hash))
2904                         goto out_free;
2905
2906                 p->md5_desc.tfm = hash;
2907         }
2908         return pool;
2909 out_free:
2910         __tcp_free_md5sig_pool(pool);
2911         return NULL;
2912 }
2913
2914 struct tcp_md5sig_pool * __percpu *tcp_alloc_md5sig_pool(struct sock *sk)
2915 {
2916         struct tcp_md5sig_pool * __percpu *pool;
2917         int alloc = 0;
2918
2919 retry:
2920         spin_lock_bh(&tcp_md5sig_pool_lock);
2921         pool = tcp_md5sig_pool;
2922         if (tcp_md5sig_users++ == 0) {
2923                 alloc = 1;
2924                 spin_unlock_bh(&tcp_md5sig_pool_lock);
2925         } else if (!pool) {
2926                 tcp_md5sig_users--;
2927                 spin_unlock_bh(&tcp_md5sig_pool_lock);
2928                 cpu_relax();
2929                 goto retry;
2930         } else
2931                 spin_unlock_bh(&tcp_md5sig_pool_lock);
2932
2933         if (alloc) {
2934                 /* we cannot hold spinlock here because this may sleep. */
2935                 struct tcp_md5sig_pool * __percpu *p;
2936
2937                 p = __tcp_alloc_md5sig_pool(sk);
2938                 spin_lock_bh(&tcp_md5sig_pool_lock);
2939                 if (!p) {
2940                         tcp_md5sig_users--;
2941                         spin_unlock_bh(&tcp_md5sig_pool_lock);
2942                         return NULL;
2943                 }
2944                 pool = tcp_md5sig_pool;
2945                 if (pool) {
2946                         /* oops, it has already been assigned. */
2947                         spin_unlock_bh(&tcp_md5sig_pool_lock);
2948                         __tcp_free_md5sig_pool(p);
2949                 } else {
2950                         tcp_md5sig_pool = pool = p;
2951                         spin_unlock_bh(&tcp_md5sig_pool_lock);
2952                 }
2953         }
2954         return pool;
2955 }
2956 EXPORT_SYMBOL(tcp_alloc_md5sig_pool);
2957
2958
2959 /**
2960  *      tcp_get_md5sig_pool - get md5sig_pool for this user
2961  *
2962  *      We use percpu structure, so if we succeed, we exit with preemption
2963  *      and BH disabled, to make sure another thread or softirq handling
2964  *      wont try to get same context.
2965  */
2966 struct tcp_md5sig_pool *tcp_get_md5sig_pool(void)
2967 {
2968         struct tcp_md5sig_pool * __percpu *p;
2969
2970         local_bh_disable();
2971
2972         spin_lock(&tcp_md5sig_pool_lock);
2973         p = tcp_md5sig_pool;
2974         if (p)
2975                 tcp_md5sig_users++;
2976         spin_unlock(&tcp_md5sig_pool_lock);
2977
2978         if (p)
2979                 return *this_cpu_ptr(p);
2980
2981         local_bh_enable();
2982         return NULL;
2983 }
2984 EXPORT_SYMBOL(tcp_get_md5sig_pool);
2985
2986 void tcp_put_md5sig_pool(void)
2987 {
2988         local_bh_enable();
2989         tcp_free_md5sig_pool();
2990 }
2991 EXPORT_SYMBOL(tcp_put_md5sig_pool);
2992
2993 int tcp_md5_hash_header(struct tcp_md5sig_pool *hp,
2994                         struct tcphdr *th)
2995 {
2996         struct scatterlist sg;
2997         int err;
2998
2999         __sum16 old_checksum = th->check;
3000         th->check = 0;
3001         /* options aren't included in the hash */
3002         sg_init_one(&sg, th, sizeof(struct tcphdr));
3003         err = crypto_hash_update(&hp->md5_desc, &sg, sizeof(struct tcphdr));
3004         th->check = old_checksum;
3005         return err;
3006 }
3007 EXPORT_SYMBOL(tcp_md5_hash_header);
3008
3009 int tcp_md5_hash_skb_data(struct tcp_md5sig_pool *hp,
3010                           struct sk_buff *skb, unsigned header_len)
3011 {
3012         struct scatterlist sg;
3013         const struct tcphdr *tp = tcp_hdr(skb);
3014         struct hash_desc *desc = &hp->md5_desc;
3015         unsigned i;
3016         const unsigned head_data_len = skb_headlen(skb) > header_len ?
3017                                        skb_headlen(skb) - header_len : 0;
3018         const struct skb_shared_info *shi = skb_shinfo(skb);
3019         struct sk_buff *frag_iter;
3020
3021         sg_init_table(&sg, 1);
3022
3023         sg_set_buf(&sg, ((u8 *) tp) + header_len, head_data_len);
3024         if (crypto_hash_update(desc, &sg, head_data_len))
3025                 return 1;
3026
3027         for (i = 0; i < shi->nr_frags; ++i) {
3028                 const struct skb_frag_struct *f = &shi->frags[i];
3029                 sg_set_page(&sg, f->page, f->size, f->page_offset);
3030                 if (crypto_hash_update(desc, &sg, f->size))
3031                         return 1;
3032         }
3033
3034         skb_walk_frags(skb, frag_iter)
3035                 if (tcp_md5_hash_skb_data(hp, frag_iter, 0))
3036                         return 1;
3037
3038         return 0;
3039 }
3040 EXPORT_SYMBOL(tcp_md5_hash_skb_data);
3041
3042 int tcp_md5_hash_key(struct tcp_md5sig_pool *hp, struct tcp_md5sig_key *key)
3043 {
3044         struct scatterlist sg;
3045
3046         sg_init_one(&sg, key->key, key->keylen);
3047         return crypto_hash_update(&hp->md5_desc, &sg, key->keylen);
3048 }
3049 EXPORT_SYMBOL(tcp_md5_hash_key);
3050
3051 #endif
3052