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  * Version:     $Id: tcp.c,v 1.216 2002/02/01 22:01:04 davem Exp $
   9  *
  10  * Authors:     Ross Biro
  11  *              Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
  12  *              Mark Evans, <evansmp@uhura.aston.ac.uk>
  13  *              Corey Minyard <wf-rch!minyard@relay.EU.net>
  14  *              Florian La Roche, <flla@stud.uni-sb.de>
  15  *              Charles Hedrick, <hedrick@klinzhai.rutgers.edu>
  16  *              Linus Torvalds, <torvalds@cs.helsinki.fi>
  17  *              Alan Cox, <gw4pts@gw4pts.ampr.org>
  18  *              Matthew Dillon, <dillon@apollo.west.oic.com>
  19  *              Arnt Gulbrandsen, <agulbra@nvg.unit.no>
  20  *              Jorge Cwik, <jorge@laser.satlink.net>
  21  *
  22  * Fixes:
  23  *              Alan Cox        :       Numerous verify_area() calls
  24  *              Alan Cox        :       Set the ACK bit on a reset
  25  *              Alan Cox        :       Stopped it crashing if it closed while
  26  *                                      sk->inuse=1 and was trying to connect
  27  *                                      (tcp_err()).
  28  *              Alan Cox        :       All icmp error handling was broken
  29  *                                      pointers passed where wrong and the
  30  *                                      socket was looked up backwards. Nobody
  31  *                                      tested any icmp error code obviously.
  32  *              Alan Cox        :       tcp_err() now handled properly. It
  33  *                                      wakes people on errors. poll
  34  *                                      behaves and the icmp error race
  35  *                                      has gone by moving it into sock.c
  36  *              Alan Cox        :       tcp_send_reset() fixed to work for
  37  *                                      everything not just packets for
  38  *                                      unknown sockets.
  39  *              Alan Cox        :       tcp option processing.
  40  *              Alan Cox        :       Reset tweaked (still not 100%) [Had
  41  *                                      syn rule wrong]
  42  *              Herp Rosmanith  :       More reset fixes
  43  *              Alan Cox        :       No longer acks invalid rst frames.
  44  *                                      Acking any kind of RST is right out.
  45  *              Alan Cox        :       Sets an ignore me flag on an rst
  46  *                                      receive otherwise odd bits of prattle
  47  *                                      escape still
  48  *              Alan Cox        :       Fixed another acking RST frame bug.
  49  *                                      Should stop LAN workplace lockups.
  50  *              Alan Cox        :       Some tidyups using the new skb list
  51  *                                      facilities
  52  *              Alan Cox        :       sk->keepopen now seems to work
  53  *              Alan Cox        :       Pulls options out correctly on accepts
  54  *              Alan Cox        :       Fixed assorted sk->rqueue->next errors
  55  *              Alan Cox        :       PSH doesn't end a TCP read. Switched a
  56  *                                      bit to skb ops.
  57  *              Alan Cox        :       Tidied tcp_data to avoid a potential
  58  *                                      nasty.
  59  *              Alan Cox        :       Added some better commenting, as the
  60  *                                      tcp is hard to follow
  61  *              Alan Cox        :       Removed incorrect check for 20 * psh
  62  *      Michael O'Reilly        :       ack < copied bug fix.
  63  *      Johannes Stille         :       Misc tcp fixes (not all in yet).
  64  *              Alan Cox        :       FIN with no memory -> CRASH
  65  *              Alan Cox        :       Added socket option proto entries.
  66  *                                      Also added awareness of them to accept.
  67  *              Alan Cox        :       Added TCP options (SOL_TCP)
  68  *              Alan Cox        :       Switched wakeup calls to callbacks,
  69  *                                      so the kernel can layer network
  70  *                                      sockets.
  71  *              Alan Cox        :       Use ip_tos/ip_ttl settings.
  72  *              Alan Cox        :       Handle FIN (more) properly (we hope).
  73  *              Alan Cox        :       RST frames sent on unsynchronised
  74  *                                      state ack error.
  75  *              Alan Cox        :       Put in missing check for SYN bit.
  76  *              Alan Cox        :       Added tcp_select_window() aka NET2E
  77  *                                      window non shrink trick.
  78  *              Alan Cox        :       Added a couple of small NET2E timer
  79  *                                      fixes
  80  *              Charles Hedrick :       TCP fixes
  81  *              Toomas Tamm     :       TCP window fixes
  82  *              Alan Cox        :       Small URG fix to rlogin ^C ack fight
  83  *              Charles Hedrick :       Rewrote most of it to actually work
  84  *              Linus           :       Rewrote tcp_read() and URG handling
  85  *                                      completely
  86  *              Gerhard Koerting:       Fixed some missing timer handling
  87  *              Matthew Dillon  :       Reworked TCP machine states as per RFC
  88  *              Gerhard Koerting:       PC/TCP workarounds
  89  *              Adam Caldwell   :       Assorted timer/timing errors
  90  *              Matthew Dillon  :       Fixed another RST bug
  91  *              Alan Cox        :       Move to kernel side addressing changes.
  92  *              Alan Cox        :       Beginning work on TCP fastpathing
  93  *                                      (not yet usable)
  94  *              Arnt Gulbrandsen:       Turbocharged tcp_check() routine.
  95  *              Alan Cox        :       TCP fast path debugging
  96  *              Alan Cox        :       Window clamping
  97  *              Michael Riepe   :       Bug in tcp_check()
  98  *              Matt Dillon     :       More TCP improvements and RST bug fixes
  99  *              Matt Dillon     :       Yet more small nasties remove from the
 100  *                                      TCP code (Be very nice to this man if
 101  *                                      tcp finally works 100%) 8)
 102  *              Alan Cox        :       BSD accept semantics.
 103  *              Alan Cox        :       Reset on closedown bug.
 104  *      Peter De Schrijver      :       ENOTCONN check missing in tcp_sendto().
 105  *              Michael Pall    :       Handle poll() after URG properly in
 106  *                                      all cases.
 107  *              Michael Pall    :       Undo the last fix in tcp_read_urg()
 108  *                                      (multi URG PUSH broke rlogin).
 109  *              Michael Pall    :       Fix the multi URG PUSH problem in
 110  *                                      tcp_readable(), poll() after URG
 111  *                                      works now.
 112  *              Michael Pall    :       recv(...,MSG_OOB) never blocks in the
 113  *                                      BSD api.
 114  *              Alan Cox        :       Changed the semantics of sk->socket to
 115  *                                      fix a race and a signal problem with
 116  *                                      accept() and async I/O.
 117  *              Alan Cox        :       Relaxed the rules on tcp_sendto().
 118  *              Yury Shevchuk   :       Really fixed accept() blocking problem.
 119  *              Craig I. Hagan  :       Allow for BSD compatible TIME_WAIT for
 120  *                                      clients/servers which listen in on
 121  *                                      fixed ports.
 122  *              Alan Cox        :       Cleaned the above up and shrank it to
 123  *                                      a sensible code size.
 124  *              Alan Cox        :       Self connect lockup fix.
 125  *              Alan Cox        :       No connect to multicast.
 126  *              Ross Biro       :       Close unaccepted children on master
 127  *                                      socket close.
 128  *              Alan Cox        :       Reset tracing code.
 129  *              Alan Cox        :       Spurious resets on shutdown.
 130  *              Alan Cox        :       Giant 15 minute/60 second timer error
 131  *              Alan Cox        :       Small whoops in polling before an
 132  *                                      accept.
 133  *              Alan Cox        :       Kept the state trace facility since
 134  *                                      it's handy for debugging.
 135  *              Alan Cox        :       More reset handler fixes.
 136  *              Alan Cox        :       Started rewriting the code based on
 137  *                                      the RFC's for other useful protocol
 138  *                                      references see: Comer, KA9Q NOS, and
 139  *                                      for a reference on the difference
 140  *                                      between specifications and how BSD
 141  *                                      works see the 4.4lite source.
 142  *              A.N.Kuznetsov   :       Don't time wait on completion of tidy
 143  *                                      close.
 144  *              Linus Torvalds  :       Fin/Shutdown & copied_seq changes.
 145  *              Linus Torvalds  :       Fixed BSD port reuse to work first syn
 146  *              Alan Cox        :       Reimplemented timers as per the RFC
 147  *                                      and using multiple timers for sanity.
 148  *              Alan Cox        :       Small bug fixes, and a lot of new
 149  *                                      comments.
 150  *              Alan Cox        :       Fixed dual reader crash by locking
 151  *                                      the buffers (much like datagram.c)
 152  *              Alan Cox        :       Fixed stuck sockets in probe. A probe
 153  *                                      now gets fed up of retrying without
 154  *                                      (even a no space) answer.
 155  *              Alan Cox        :       Extracted closing code better
 156  *              Alan Cox        :       Fixed the closing state machine to
 157  *                                      resemble the RFC.
 158  *              Alan Cox        :       More 'per spec' fixes.
 159  *              Jorge Cwik      :       Even faster checksumming.
 160  *              Alan Cox        :       tcp_data() doesn't ack illegal PSH
 161  *                                      only frames. At least one pc tcp stack
 162  *                                      generates them.
 163  *              Alan Cox        :       Cache last socket.
 164  *              Alan Cox        :       Per route irtt.
 165  *              Matt Day        :       poll()->select() match BSD precisely on error
 166  *              Alan Cox        :       New buffers
 167  *              Marc Tamsky     :       Various sk->prot->retransmits and
 168  *                                      sk->retransmits misupdating fixed.
 169  *                                      Fixed tcp_write_timeout: stuck close,
 170  *                                      and TCP syn retries gets used now.
 171  *              Mark Yarvis     :       In tcp_read_wakeup(), don't send an
 172  *                                      ack if state is TCP_CLOSED.
 173  *              Alan Cox        :       Look up device on a retransmit - routes may
 174  *                                      change. Doesn't yet cope with MSS shrink right
 175  *                                      but it's a start!
 176  *              Marc Tamsky     :       Closing in closing fixes.
 177  *              Mike Shaver     :       RFC1122 verifications.
 178  *              Alan Cox        :       rcv_saddr errors.
 179  *              Alan Cox        :       Block double connect().
 180  *              Alan Cox        :       Small hooks for enSKIP.
 181  *              Alexey Kuznetsov:       Path MTU discovery.
 182  *              Alan Cox        :       Support soft errors.
 183  *              Alan Cox        :       Fix MTU discovery pathological case
 184  *                                      when the remote claims no mtu!
 185  *              Marc Tamsky     :       TCP_CLOSE fix.
 186  *              Colin (G3TNE)   :       Send a reset on syn ack replies in
 187  *                                      window but wrong (fixes NT lpd problems)
 188  *              Pedro Roque     :       Better TCP window handling, delayed ack.
 189  *              Joerg Reuter    :       No modification of locked buffers in
 190  *                                      tcp_do_retransmit()
 191  *              Eric Schenk     :       Changed receiver side silly window
 192  *                                      avoidance algorithm to BSD style
 193  *                                      algorithm. This doubles throughput
 194  *                                      against machines running Solaris,
 195  *                                      and seems to result in general
 196  *                                      improvement.
 197  *      Stefan Magdalinski      :       adjusted tcp_readable() to fix FIONREAD
 198  *      Willy Konynenberg       :       Transparent proxying support.
 199  *      Mike McLagan            :       Routing by source
 200  *              Keith Owens     :       Do proper merging with partial SKB's in
 201  *                                      tcp_do_sendmsg to avoid burstiness.
 202  *              Eric Schenk     :       Fix fast close down bug with
 203  *                                      shutdown() followed by close().
 204  *              Andi Kleen      :       Make poll agree with SIGIO
 205  *      Salvatore Sanfilippo    :       Support SO_LINGER with linger == 1 and
 206  *                                      lingertime == 0 (RFC 793 ABORT Call)
 207  *      Hirokazu Takahashi      :       Use copy_from_user() instead of
 208  *                                      csum_and_copy_from_user() if possible.
 209  *
 210  *              This program is free software; you can redistribute it and/or
 211  *              modify it under the terms of the GNU General Public License
 212  *              as published by the Free Software Foundation; either version
 213  *              2 of the License, or(at your option) any later version.
 214  *
 215  * Description of States:
 216  *
 217  *      TCP_SYN_SENT            sent a connection request, waiting for ack
 218  *
 219  *      TCP_SYN_RECV            received a connection request, sent ack,
 220  *                              waiting for final ack in three-way handshake.
 221  *
 222  *      TCP_ESTABLISHED         connection established
 223  *
 224  *      TCP_FIN_WAIT1           our side has shutdown, waiting to complete
 225  *                              transmission of remaining buffered data
 226  *
 227  *      TCP_FIN_WAIT2           all buffered data sent, waiting for remote
 228  *                              to shutdown
 229  *
 230  *      TCP_CLOSING             both sides have shutdown but we still have
 231  *                              data we have to finish sending
 232  *
 233  *      TCP_TIME_WAIT           timeout to catch resent junk before entering
 234  *                              closed, can only be entered from FIN_WAIT2
 235  *                              or CLOSING.  Required because the other end
 236  *                              may not have gotten our last ACK causing it
 237  *                              to retransmit the data packet (which we ignore)
 238  *
 239  *      TCP_CLOSE_WAIT          remote side has shutdown and is waiting for
 240  *                              us to finish writing our data and to shutdown
 241  *                              (we have to close() to move on to LAST_ACK)
 242  *
 243  *      TCP_LAST_ACK            out side has shutdown after remote has
 244  *                              shutdown.  There may still be data in our
 245  *                              buffer that we have to finish sending
 246  *
 247  *      TCP_CLOSE               socket is finished
 248  */
 249
 250 #include <linux/module.h>
 251 #include <linux/types.h>
 252 #include <linux/fcntl.h>
 253 #include <linux/poll.h>
 254 #include <linux/init.h>
 255 #include <linux/fs.h>
 256 #include <linux/random.h>
 257 #include <linux/bootmem.h>
 258 #include <linux/cache.h>
 259 #include <linux/err.h>
 260 #include <linux/crypto.h>
 261
 262 #include <net/icmp.h>
 263 #include <net/tcp.h>
 264 #include <net/xfrm.h>
 265 #include <net/ip.h>
 266 #include <net/netdma.h>
 267
 268 #include <asm/uaccess.h>
 269 #include <asm/ioctls.h>
 270
 271 int sysctl_tcp_fin_timeout __read_mostly = TCP_FIN_TIMEOUT;
 272
 273 DEFINE_SNMP_STAT(struct tcp_mib, tcp_statistics) __read_mostly;
 274
 275 atomic_t tcp_orphan_count = ATOMIC_INIT(0);
 276
 277 EXPORT_SYMBOL_GPL(tcp_orphan_count);
 278
 279 int sysctl_tcp_mem[3] __read_mostly;
 280 int sysctl_tcp_wmem[3] __read_mostly;
 281 int sysctl_tcp_rmem[3] __read_mostly;
 282
 283 EXPORT_SYMBOL(sysctl_tcp_mem);
 284 EXPORT_SYMBOL(sysctl_tcp_rmem);
 285 EXPORT_SYMBOL(sysctl_tcp_wmem);
 286
 287 atomic_t tcp_memory_allocated;  /* Current allocated memory. */
 288 atomic_t tcp_sockets_allocated; /* Current number of TCP sockets. */
 289
 290 EXPORT_SYMBOL(tcp_memory_allocated);
 291 EXPORT_SYMBOL(tcp_sockets_allocated);
 292
 293 /*
 294  * Pressure flag: try to collapse.
 295  * Technical note: it is used by multiple contexts non atomically.
 296  * All the sk_stream_mem_schedule() is of this nature: accounting
 297  * is strict, actions are advisory and have some latency.
 298  */
 299 int tcp_memory_pressure __read_mostly;
 300
 301 EXPORT_SYMBOL(tcp_memory_pressure);
 302
 303 void tcp_enter_memory_pressure(void)
 304 {
 305         if (!tcp_memory_pressure) {
 306                 NET_INC_STATS(LINUX_MIB_TCPMEMORYPRESSURES);
 307                 tcp_memory_pressure = 1;
 308         }
 309 }
 310
 311 EXPORT_SYMBOL(tcp_enter_memory_pressure);
 312
 313 /*
 314  *      Wait for a TCP event.
 315  *
 316  *      Note that we don't need to lock the socket, as the upper poll layers
 317  *      take care of normal races (between the test and the event) and we don't
 318  *      go look at any of the socket buffers directly.
 319  */
 320 unsigned int tcp_poll(struct file *file, struct socket *sock, poll_table *wait)
 321 {
 322         unsigned int mask;
 323         struct sock *sk = sock->sk;
 324         struct tcp_sock *tp = tcp_sk(sk);
 325
 326         poll_wait(file, sk->sk_sleep, wait);
 327         if (sk->sk_state == TCP_LISTEN)
 328                 return inet_csk_listen_poll(sk);
 329
 330         /* Socket is not locked. We are protected from async events
 331            by poll logic and correct handling of state changes
 332            made by another threads is impossible in any case.
 333          */
 334
 335         mask = 0;
 336         if (sk->sk_err)
 337                 mask = POLLERR;
 338
 339         /*
 340          * POLLHUP is certainly not done right. But poll() doesn't
 341          * have a notion of HUP in just one direction, and for a
 342          * socket the read side is more interesting.
 343          *
 344          * Some poll() documentation says that POLLHUP is incompatible
 345          * with the POLLOUT/POLLWR flags, so somebody should check this
 346          * all. But careful, it tends to be safer to return too many
 347          * bits than too few, and you can easily break real applications
 348          * if you don't tell them that something has hung up!
 349          *
 350          * Check-me.
 351          *
 352          * Check number 1. POLLHUP is _UNMASKABLE_ event (see UNIX98 and
 353          * our fs/select.c). It means that after we received EOF,
 354          * poll always returns immediately, making impossible poll() on write()
 355          * in state CLOSE_WAIT. One solution is evident --- to set POLLHUP
 356          * if and only if shutdown has been made in both directions.
 357          * Actually, it is interesting to look how Solaris and DUX
 358          * solve this dilemma. I would prefer, if PULLHUP were maskable,
 359          * then we could set it on SND_SHUTDOWN. BTW examples given
 360          * in Stevens' books assume exactly this behaviour, it explains
 361          * why PULLHUP is incompatible with POLLOUT.    --ANK
 362          *
 363          * NOTE. Check for TCP_CLOSE is added. The goal is to prevent
 364          * blocking on fresh not-connected or disconnected socket. --ANK
 365          */
 366         if (sk->sk_shutdown == SHUTDOWN_MASK || sk->sk_state == TCP_CLOSE)
 367                 mask |= POLLHUP;
 368         if (sk->sk_shutdown & RCV_SHUTDOWN)
 369                 mask |= POLLIN | POLLRDNORM | POLLRDHUP;
 370
 371         /* Connected? */
 372         if ((1 << sk->sk_state) & ~(TCPF_SYN_SENT | TCPF_SYN_RECV)) {
 373                 /* Potential race condition. If read of tp below will
 374                  * escape above sk->sk_state, we can be illegally awaken
 375                  * in SYN_* states. */
 376                 if ((tp->rcv_nxt != tp->copied_seq) &&
 377                     (tp->urg_seq != tp->copied_seq ||
 378                      tp->rcv_nxt != tp->copied_seq + 1 ||
 379                      sock_flag(sk, SOCK_URGINLINE) || !tp->urg_data))
 380                         mask |= POLLIN | POLLRDNORM;
 381
 382                 if (!(sk->sk_shutdown & SEND_SHUTDOWN)) {
 383                         if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk)) {
 384                                 mask |= POLLOUT | POLLWRNORM;
 385                         } else {  /* send SIGIO later */
 386                                 set_bit(SOCK_ASYNC_NOSPACE,
 387                                         &sk->sk_socket->flags);
 388                                 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
 389
 390                                 /* Race breaker. If space is freed after
 391                                  * wspace test but before the flags are set,
 392                                  * IO signal will be lost.
 393                                  */
 394                                 if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk))
 395                                         mask |= POLLOUT | POLLWRNORM;
 396                         }
 397                 }
 398
 399                 if (tp->urg_data & TCP_URG_VALID)
 400                         mask |= POLLPRI;
 401         }
 402         return mask;
 403 }
 404
 405 int tcp_ioctl(struct sock *sk, int cmd, unsigned long arg)
 406 {
 407         struct tcp_sock *tp = tcp_sk(sk);
 408         int answ;
 409
 410         switch (cmd) {
 411         case SIOCINQ:
 412                 if (sk->sk_state == TCP_LISTEN)
 413                         return -EINVAL;
 414
 415                 lock_sock(sk);
 416                 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
 417                         answ = 0;
 418                 else if (sock_flag(sk, SOCK_URGINLINE) ||
 419                          !tp->urg_data ||
 420                          before(tp->urg_seq, tp->copied_seq) ||
 421                          !before(tp->urg_seq, tp->rcv_nxt)) {
 422                         answ = tp->rcv_nxt - tp->copied_seq;
 423
 424                         /* Subtract 1, if FIN is in queue. */
 425                         if (answ && !skb_queue_empty(&sk->sk_receive_queue))
 426                                 answ -=
 427                        tcp_hdr((struct sk_buff *)sk->sk_receive_queue.prev)->fin;
 428                 } else
 429                         answ = tp->urg_seq - tp->copied_seq;
 430                 release_sock(sk);
 431                 break;
 432         case SIOCATMARK:
 433                 answ = tp->urg_data && tp->urg_seq == tp->copied_seq;
 434                 break;
 435         case SIOCOUTQ:
 436                 if (sk->sk_state == TCP_LISTEN)
 437                         return -EINVAL;
 438
 439                 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
 440                         answ = 0;
 441                 else
 442                         answ = tp->write_seq - tp->snd_una;
 443                 break;
 444         default:
 445                 return -ENOIOCTLCMD;
 446         }
 447
 448         return put_user(answ, (int __user *)arg);
 449 }
 450
 451 static inline void tcp_mark_push(struct tcp_sock *tp, struct sk_buff *skb)
 452 {
 453         TCP_SKB_CB(skb)->flags |= TCPCB_FLAG_PSH;
 454         tp->pushed_seq = tp->write_seq;
 455 }
 456
 457 static inline int forced_push(struct tcp_sock *tp)
 458 {
 459         return after(tp->write_seq, tp->pushed_seq + (tp->max_window >> 1));
 460 }
 461
 462 static inline void skb_entail(struct sock *sk, struct sk_buff *skb)
 463 {
 464         struct tcp_sock *tp = tcp_sk(sk);
 465         struct tcp_skb_cb *tcb = TCP_SKB_CB(skb);
 466
 467         skb->csum    = 0;
 468         tcb->seq     = tcb->end_seq = tp->write_seq;
 469         tcb->flags   = TCPCB_FLAG_ACK;
 470         tcb->sacked  = 0;
 471         skb_header_release(skb);
 472         tcp_add_write_queue_tail(sk, skb);
 473         sk_charge_skb(sk, skb);
 474         if (tp->nonagle & TCP_NAGLE_PUSH)
 475                 tp->nonagle &= ~TCP_NAGLE_PUSH;
 476 }
 477
 478 static inline void tcp_mark_urg(struct tcp_sock *tp, int flags,
 479                                 struct sk_buff *skb)
 480 {
 481         if (flags & MSG_OOB) {
 482                 tp->urg_mode = 1;
 483                 tp->snd_up = tp->write_seq;
 484                 TCP_SKB_CB(skb)->sacked |= TCPCB_URG;
 485         }
 486 }
 487
 488 static inline void tcp_push(struct sock *sk, int flags, int mss_now,
 489                             int nonagle)
 490 {
 491         struct tcp_sock *tp = tcp_sk(sk);
 492
 493         if (tcp_send_head(sk)) {
 494                 struct sk_buff *skb = tcp_write_queue_tail(sk);
 495                 if (!(flags & MSG_MORE) || forced_push(tp))
 496                         tcp_mark_push(tp, skb);
 497                 tcp_mark_urg(tp, flags, skb);
 498                 __tcp_push_pending_frames(sk, mss_now,
 499                                           (flags & MSG_MORE) ? TCP_NAGLE_CORK : nonagle);
 500         }
 501 }
 502
 503 static ssize_t do_tcp_sendpages(struct sock *sk, struct page **pages, int poffset,
 504                          size_t psize, int flags)
 505 {
 506         struct tcp_sock *tp = tcp_sk(sk);
 507         int mss_now, size_goal;
 508         int err;
 509         ssize_t copied;
 510         long timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
 511
 512         /* Wait for a connection to finish. */
 513         if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT))
 514                 if ((err = sk_stream_wait_connect(sk, &timeo)) != 0)
 515                         goto out_err;
 516
 517         clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
 518
 519         mss_now = tcp_current_mss(sk, !(flags&MSG_OOB));
 520         size_goal = tp->xmit_size_goal;
 521         copied = 0;
 522
 523         err = -EPIPE;
 524         if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
 525                 goto do_error;
 526
 527         while (psize > 0) {
 528                 struct sk_buff *skb = tcp_write_queue_tail(sk);
 529                 struct page *page = pages[poffset / PAGE_SIZE];
 530                 int copy, i, can_coalesce;
 531                 int offset = poffset % PAGE_SIZE;
 532                 int size = min_t(size_t, psize, PAGE_SIZE - offset);
 533
 534                 if (!tcp_send_head(sk) || (copy = size_goal - skb->len) <= 0) {
 535 new_segment:
 536                         if (!sk_stream_memory_free(sk))
 537                                 goto wait_for_sndbuf;
 538
 539                         skb = sk_stream_alloc_pskb(sk, 0, 0,
 540                                                    sk->sk_allocation);
 541                         if (!skb)
 542                                 goto wait_for_memory;
 543
 544                         skb_entail(sk, skb);
 545                         copy = size_goal;
 546                 }
 547
 548                 if (copy > size)
 549                         copy = size;
 550
 551                 i = skb_shinfo(skb)->nr_frags;
 552                 can_coalesce = skb_can_coalesce(skb, i, page, offset);
 553                 if (!can_coalesce && i >= MAX_SKB_FRAGS) {
 554                         tcp_mark_push(tp, skb);
 555                         goto new_segment;
 556                 }
 557                 if (!sk_stream_wmem_schedule(sk, copy))
 558                         goto wait_for_memory;
 559
 560                 if (can_coalesce) {
 561                         skb_shinfo(skb)->frags[i - 1].size += copy;
 562                 } else {
 563                         get_page(page);
 564                         skb_fill_page_desc(skb, i, page, offset, copy);
 565                 }
 566
 567                 skb->len += copy;
 568                 skb->data_len += copy;
 569                 skb->truesize += copy;
 570                 sk->sk_wmem_queued += copy;
 571                 sk->sk_forward_alloc -= copy;
 572                 skb->ip_summed = CHECKSUM_PARTIAL;
 573                 tp->write_seq += copy;
 574                 TCP_SKB_CB(skb)->end_seq += copy;
 575                 skb_shinfo(skb)->gso_segs = 0;
 576
 577                 if (!copied)
 578                         TCP_SKB_CB(skb)->flags &= ~TCPCB_FLAG_PSH;
 579
 580                 copied += copy;
 581                 poffset += copy;
 582                 if (!(psize -= copy))
 583                         goto out;
 584
 585                 if (skb->len < mss_now || (flags & MSG_OOB))
 586                         continue;
 587
 588                 if (forced_push(tp)) {
 589                         tcp_mark_push(tp, skb);
 590                         __tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH);
 591                 } else if (skb == tcp_send_head(sk))
 592                         tcp_push_one(sk, mss_now);
 593                 continue;
 594
 595 wait_for_sndbuf:
 596                 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
 597 wait_for_memory:
 598                 if (copied)
 599                         tcp_push(sk, flags & ~MSG_MORE, mss_now, TCP_NAGLE_PUSH);
 600
 601                 if ((err = sk_stream_wait_memory(sk, &timeo)) != 0)
 602                         goto do_error;
 603
 604                 mss_now = tcp_current_mss(sk, !(flags&MSG_OOB));
 605                 size_goal = tp->xmit_size_goal;
 606         }
 607
 608 out:
 609         if (copied)
 610                 tcp_push(sk, flags, mss_now, tp->nonagle);
 611         return copied;
 612
 613 do_error:
 614         if (copied)
 615                 goto out;
 616 out_err:
 617         return sk_stream_error(sk, flags, err);
 618 }
 619
 620 ssize_t tcp_sendpage(struct socket *sock, struct page *page, int offset,
 621                      size_t size, int flags)
 622 {
 623         ssize_t res;
 624         struct sock *sk = sock->sk;
 625
 626         if (!(sk->sk_route_caps & NETIF_F_SG) ||
 627             !(sk->sk_route_caps & NETIF_F_ALL_CSUM))
 628                 return sock_no_sendpage(sock, page, offset, size, flags);
 629
 630         lock_sock(sk);
 631         TCP_CHECK_TIMER(sk);
 632         res = do_tcp_sendpages(sk, &page, offset, size, flags);
 633         TCP_CHECK_TIMER(sk);
 634         release_sock(sk);
 635         return res;
 636 }
 637
 638 #define TCP_PAGE(sk)    (sk->sk_sndmsg_page)
 639 #define TCP_OFF(sk)     (sk->sk_sndmsg_off)
 640
 641 static inline int select_size(struct sock *sk)
 642 {
 643         struct tcp_sock *tp = tcp_sk(sk);
 644         int tmp = tp->mss_cache;
 645
 646         if (sk->sk_route_caps & NETIF_F_SG) {
 647                 if (sk_can_gso(sk))
 648                         tmp = 0;
 649                 else {
 650                         int pgbreak = SKB_MAX_HEAD(MAX_TCP_HEADER);
 651
 652                         if (tmp >= pgbreak &&
 653                             tmp <= pgbreak + (MAX_SKB_FRAGS - 1) * PAGE_SIZE)
 654                                 tmp = pgbreak;
 655                 }
 656         }
 657
 658         return tmp;
 659 }
 660
 661 int tcp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
 662                 size_t size)
 663 {
 664         struct iovec *iov;
 665         struct tcp_sock *tp = tcp_sk(sk);
 666         struct sk_buff *skb;
 667         int iovlen, flags;
 668         int mss_now, size_goal;
 669         int err, copied;
 670         long timeo;
 671
 672         lock_sock(sk);
 673         TCP_CHECK_TIMER(sk);
 674
 675         flags = msg->msg_flags;
 676         timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
 677
 678         /* Wait for a connection to finish. */
 679         if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT))
 680                 if ((err = sk_stream_wait_connect(sk, &timeo)) != 0)
 681                         goto out_err;
 682
 683         /* This should be in poll */
 684         clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
 685
 686         mss_now = tcp_current_mss(sk, !(flags&MSG_OOB));
 687         size_goal = tp->xmit_size_goal;
 688
 689         /* Ok commence sending. */
 690         iovlen = msg->msg_iovlen;
 691         iov = msg->msg_iov;
 692         copied = 0;
 693
 694         err = -EPIPE;
 695         if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
 696                 goto do_error;
 697
 698         while (--iovlen >= 0) {
 699                 int seglen = iov->iov_len;
 700                 unsigned char __user *from = iov->iov_base;
 701
 702                 iov++;
 703
 704                 while (seglen > 0) {
 705                         int copy;
 706
 707                         skb = tcp_write_queue_tail(sk);
 708
 709                         if (!tcp_send_head(sk) ||
 710                             (copy = size_goal - skb->len) <= 0) {
 711
 712 new_segment:
 713                                 /* Allocate new segment. If the interface is SG,
 714                                  * allocate skb fitting to single page.
 715                                  */
 716                                 if (!sk_stream_memory_free(sk))
 717                                         goto wait_for_sndbuf;
 718
 719                                 skb = sk_stream_alloc_pskb(sk, select_size(sk),
 720                                                            0, sk->sk_allocation);
 721                                 if (!skb)
 722                                         goto wait_for_memory;
 723
 724                                 /*
 725                                  * Check whether we can use HW checksum.
 726                                  */
 727                                 if (sk->sk_route_caps & NETIF_F_ALL_CSUM)
 728                                         skb->ip_summed = CHECKSUM_PARTIAL;
 729
 730                                 skb_entail(sk, skb);
 731                                 copy = size_goal;
 732                         }
 733
 734                         /* Try to append data to the end of skb. */
 735                         if (copy > seglen)
 736                                 copy = seglen;
 737
 738                         /* Where to copy to? */
 739                         if (skb_tailroom(skb) > 0) {
 740                                 /* We have some space in skb head. Superb! */
 741                                 if (copy > skb_tailroom(skb))
 742                                         copy = skb_tailroom(skb);
 743                                 if ((err = skb_add_data(skb, from, copy)) != 0)
 744                                         goto do_fault;
 745                         } else {
 746                                 int merge = 0;
 747                                 int i = skb_shinfo(skb)->nr_frags;
 748                                 struct page *page = TCP_PAGE(sk);
 749                                 int off = TCP_OFF(sk);
 750
 751                                 if (skb_can_coalesce(skb, i, page, off) &&
 752                                     off != PAGE_SIZE) {
 753                                         /* We can extend the last page
 754                                          * fragment. */
 755                                         merge = 1;
 756                                 } else if (i == MAX_SKB_FRAGS ||
 757                                            (!i &&
 758                                            !(sk->sk_route_caps & NETIF_F_SG))) {
 759                                         /* Need to add new fragment and cannot
 760                                          * do this because interface is non-SG,
 761                                          * or because all the page slots are
 762                                          * busy. */
 763                                         tcp_mark_push(tp, skb);
 764                                         goto new_segment;
 765                                 } else if (page) {
 766                                         if (off == PAGE_SIZE) {
 767                                                 put_page(page);
 768                                                 TCP_PAGE(sk) = page = NULL;
 769                                                 off = 0;
 770                                         }
 771                                 } else
 772                                         off = 0;
 773
 774                                 if (copy > PAGE_SIZE - off)
 775                                         copy = PAGE_SIZE - off;
 776
 777                                 if (!sk_stream_wmem_schedule(sk, copy))
 778                                         goto wait_for_memory;
 779
 780                                 if (!page) {
 781                                         /* Allocate new cache page. */
 782                                         if (!(page = sk_stream_alloc_page(sk)))
 783                                                 goto wait_for_memory;
 784                                 }
 785
 786                                 /* Time to copy data. We are close to
 787                                  * the end! */
 788                                 err = skb_copy_to_page(sk, from, skb, page,
 789                                                        off, copy);
 790                                 if (err) {
 791                                         /* If this page was new, give it to the
 792                                          * socket so it does not get leaked.
 793                                          */
 794                                         if (!TCP_PAGE(sk)) {
 795                                                 TCP_PAGE(sk) = page;
 796                                                 TCP_OFF(sk) = 0;
 797                                         }
 798                                         goto do_error;
 799                                 }
 800
 801                                 /* Update the skb. */
 802                                 if (merge) {
 803                                         skb_shinfo(skb)->frags[i - 1].size +=
 804                                                                         copy;
 805                                 } else {
 806                                         skb_fill_page_desc(skb, i, page, off, copy);
 807                                         if (TCP_PAGE(sk)) {
 808                                                 get_page(page);
 809                                         } else if (off + copy < PAGE_SIZE) {
 810                                                 get_page(page);
 811                                                 TCP_PAGE(sk) = page;
 812                                         }
 813                                 }
 814
 815                                 TCP_OFF(sk) = off + copy;
 816                         }
 817
 818                         if (!copied)
 819                                 TCP_SKB_CB(skb)->flags &= ~TCPCB_FLAG_PSH;
 820
 821                         tp->write_seq += copy;
 822                         TCP_SKB_CB(skb)->end_seq += copy;
 823                         skb_shinfo(skb)->gso_segs = 0;
 824
 825                         from += copy;
 826                         copied += copy;
 827                         if ((seglen -= copy) == 0 && iovlen == 0)
 828                                 goto out;
 829
 830                         if (skb->len < mss_now || (flags & MSG_OOB))
 831                                 continue;
 832
 833                         if (forced_push(tp)) {
 834                                 tcp_mark_push(tp, skb);
 835                                 __tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH);
 836                         } else if (skb == tcp_send_head(sk))
 837                                 tcp_push_one(sk, mss_now);
 838                         continue;
 839
 840 wait_for_sndbuf:
 841                         set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
 842 wait_for_memory:
 843                         if (copied)
 844                                 tcp_push(sk, flags & ~MSG_MORE, mss_now, TCP_NAGLE_PUSH);
 845
 846                         if ((err = sk_stream_wait_memory(sk, &timeo)) != 0)
 847                                 goto do_error;
 848
 849                         mss_now = tcp_current_mss(sk, !(flags&MSG_OOB));
 850                         size_goal = tp->xmit_size_goal;
 851                 }
 852         }
 853
 854 out:
 855         if (copied)
 856                 tcp_push(sk, flags, mss_now, tp->nonagle);
 857         TCP_CHECK_TIMER(sk);
 858         release_sock(sk);
 859         return copied;
 860
 861 do_fault:
 862         if (!skb->len) {
 863                 tcp_unlink_write_queue(skb, sk);
 864                 /* It is the one place in all of TCP, except connection
 865                  * reset, where we can be unlinking the send_head.
 866                  */
 867                 tcp_check_send_head(sk, skb);
 868                 sk_stream_free_skb(sk, skb);
 869         }
 870
 871 do_error:
 872         if (copied)
 873                 goto out;
 874 out_err:
 875         err = sk_stream_error(sk, flags, err);
 876         TCP_CHECK_TIMER(sk);
 877         release_sock(sk);
 878         return err;
 879 }
 880
 881 /*
 882  *      Handle reading urgent data. BSD has very simple semantics for
 883  *      this, no blocking and very strange errors 8)
 884  */
 885
 886 static int tcp_recv_urg(struct sock *sk, long timeo,
 887                         struct msghdr *msg, int len, int flags,
 888                         int *addr_len)
 889 {
 890         struct tcp_sock *tp = tcp_sk(sk);
 891
 892         /* No URG data to read. */
 893         if (sock_flag(sk, SOCK_URGINLINE) || !tp->urg_data ||
 894             tp->urg_data == TCP_URG_READ)
 895                 return -EINVAL; /* Yes this is right ! */
 896
 897         if (sk->sk_state == TCP_CLOSE && !sock_flag(sk, SOCK_DONE))
 898                 return -ENOTCONN;
 899
 900         if (tp->urg_data & TCP_URG_VALID) {
 901                 int err = 0;
 902                 char c = tp->urg_data;
 903
 904                 if (!(flags & MSG_PEEK))
 905                         tp->urg_data = TCP_URG_READ;
 906
 907                 /* Read urgent data. */
 908                 msg->msg_flags |= MSG_OOB;
 909
 910                 if (len > 0) {
 911                         if (!(flags & MSG_TRUNC))
 912                                 err = memcpy_toiovec(msg->msg_iov, &c, 1);
 913                         len = 1;
 914                 } else
 915                         msg->msg_flags |= MSG_TRUNC;
 916
 917                 return err ? -EFAULT : len;
 918         }
 919
 920         if (sk->sk_state == TCP_CLOSE || (sk->sk_shutdown & RCV_SHUTDOWN))
 921                 return 0;
 922
 923         /* Fixed the recv(..., MSG_OOB) behaviour.  BSD docs and
 924          * the available implementations agree in this case:
 925          * this call should never block, independent of the
 926          * blocking state of the socket.
 927          * Mike <pall@rz.uni-karlsruhe.de>
 928          */
 929         return -EAGAIN;
 930 }
 931
 932 /* Clean up the receive buffer for full frames taken by the user,
 933  * then send an ACK if necessary.  COPIED is the number of bytes
 934  * tcp_recvmsg has given to the user so far, it speeds up the
 935  * calculation of whether or not we must ACK for the sake of
 936  * a window update.
 937  */
 938 void tcp_cleanup_rbuf(struct sock *sk, int copied)
 939 {
 940         struct tcp_sock *tp = tcp_sk(sk);
 941         int time_to_ack = 0;
 942
 943 #if TCP_DEBUG
 944         struct sk_buff *skb = skb_peek(&sk->sk_receive_queue);
 945
 946         BUG_TRAP(!skb || before(tp->copied_seq, TCP_SKB_CB(skb)->end_seq));
 947 #endif
 948
 949         if (inet_csk_ack_scheduled(sk)) {
 950                 const struct inet_connection_sock *icsk = inet_csk(sk);
 951                    /* Delayed ACKs frequently hit locked sockets during bulk
 952                     * receive. */
 953                 if (icsk->icsk_ack.blocked ||
 954                     /* Once-per-two-segments ACK was not sent by tcp_input.c */
 955                     tp->rcv_nxt - tp->rcv_wup > icsk->icsk_ack.rcv_mss ||
 956                     /*
 957                      * If this read emptied read buffer, we send ACK, if
 958                      * connection is not bidirectional, user drained
 959                      * receive buffer and there was a small segment
 960                      * in queue.
 961                      */
 962                     (copied > 0 &&
 963                      ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED2) ||
 964                       ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED) &&
 965                        !icsk->icsk_ack.pingpong)) &&
 966                       !atomic_read(&sk->sk_rmem_alloc)))
 967                         time_to_ack = 1;
 968         }
 969
 970         /* We send an ACK if we can now advertise a non-zero window
 971          * which has been raised "significantly".
 972          *
 973          * Even if window raised up to infinity, do not send window open ACK
 974          * in states, where we will not receive more. It is useless.
 975          */
 976         if (copied > 0 && !time_to_ack && !(sk->sk_shutdown & RCV_SHUTDOWN)) {
 977                 __u32 rcv_window_now = tcp_receive_window(tp);
 978
 979                 /* Optimize, __tcp_select_window() is not cheap. */
 980                 if (2*rcv_window_now <= tp->window_clamp) {
 981                         __u32 new_window = __tcp_select_window(sk);
 982
 983                         /* Send ACK now, if this read freed lots of space
 984                          * in our buffer. Certainly, new_window is new window.
 985                          * We can advertise it now, if it is not less than current one.
 986                          * "Lots" means "at least twice" here.
 987                          */
 988                         if (new_window && new_window >= 2 * rcv_window_now)
 989                                 time_to_ack = 1;
 990                 }
 991         }
 992         if (time_to_ack)
 993                 tcp_send_ack(sk);
 994 }
 995
 996 static void tcp_prequeue_process(struct sock *sk)
 997 {
 998         struct sk_buff *skb;
 999         struct tcp_sock *tp = tcp_sk(sk);
1000
1001         NET_INC_STATS_USER(LINUX_MIB_TCPPREQUEUED);
1002
1003         /* RX process wants to run with disabled BHs, though it is not
1004          * necessary */
1005         local_bh_disable();
1006         while ((skb = __skb_dequeue(&tp->ucopy.prequeue)) != NULL)
1007                 sk->sk_backlog_rcv(sk, skb);
1008         local_bh_enable();
1009
1010         /* Clear memory counter. */
1011         tp->ucopy.memory = 0;
1012 }
1013
1014 static inline struct sk_buff *tcp_recv_skb(struct sock *sk, u32 seq, u32 *off)
1015 {
1016         struct sk_buff *skb;
1017         u32 offset;
1018
1019         skb_queue_walk(&sk->sk_receive_queue, skb) {
1020                 offset = seq - TCP_SKB_CB(skb)->seq;
1021                 if (tcp_hdr(skb)->syn)
1022                         offset--;
1023                 if (offset < skb->len || tcp_hdr(skb)->fin) {
1024                         *off = offset;
1025                         return skb;
1026                 }
1027         }
1028         return NULL;
1029 }
1030
1031 /*
1032  * This routine provides an alternative to tcp_recvmsg() for routines
1033  * that would like to handle copying from skbuffs directly in 'sendfile'
1034  * fashion.
1035  * Note:
1036  *      - It is assumed that the socket was locked by the caller.
1037  *      - The routine does not block.
1038  *      - At present, there is no support for reading OOB data
1039  *        or for 'peeking' the socket using this routine
1040  *        (although both would be easy to implement).
1041  */
1042 int tcp_read_sock(struct sock *sk, read_descriptor_t *desc,
1043                   sk_read_actor_t recv_actor)
1044 {
1045         struct sk_buff *skb;
1046         struct tcp_sock *tp = tcp_sk(sk);
1047         u32 seq = tp->copied_seq;
1048         u32 offset;
1049         int copied = 0;
1050
1051         if (sk->sk_state == TCP_LISTEN)
1052                 return -ENOTCONN;
1053         while ((skb = tcp_recv_skb(sk, seq, &offset)) != NULL) {
1054                 if (offset < skb->len) {
1055                         size_t used, len;
1056
1057                         len = skb->len - offset;
1058                         /* Stop reading if we hit a patch of urgent data */
1059                         if (tp->urg_data) {
1060                                 u32 urg_offset = tp->urg_seq - seq;
1061                                 if (urg_offset < len)
1062                                         len = urg_offset;
1063                                 if (!len)
1064                                         break;
1065                         }
1066                         used = recv_actor(desc, skb, offset, len);
1067                         if (used <= len) {
1068                                 seq += used;
1069                                 copied += used;
1070                                 offset += used;
1071                         }
1072                         if (offset != skb->len)
1073                                 break;
1074                 }
1075                 if (tcp_hdr(skb)->fin) {
1076                         sk_eat_skb(sk, skb, 0);
1077                         ++seq;
1078                         break;
1079                 }
1080                 sk_eat_skb(sk, skb, 0);
1081                 if (!desc->count)
1082                         break;
1083         }
1084         tp->copied_seq = seq;
1085
1086         tcp_rcv_space_adjust(sk);
1087
1088         /* Clean up data we have read: This will do ACK frames. */
1089         if (copied)
1090                 tcp_cleanup_rbuf(sk, copied);
1091         return copied;
1092 }
1093
1094 /*
1095  *      This routine copies from a sock struct into the user buffer.
1096  *
1097  *      Technical note: in 2.3 we work on _locked_ socket, so that
1098  *      tricks with *seq access order and skb->users are not required.
1099  *      Probably, code can be easily improved even more.
1100  */
1101
1102 int tcp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
1103                 size_t len, int nonblock, int flags, int *addr_len)
1104 {
1105         struct tcp_sock *tp = tcp_sk(sk);
1106         int copied = 0;
1107         u32 peek_seq;
1108         u32 *seq;
1109         unsigned long used;
1110         int err;
1111         int target;             /* Read at least this many bytes */
1112         long timeo;
1113         struct task_struct *user_recv = NULL;
1114         int copied_early = 0;
1115
1116         lock_sock(sk);
1117
1118         TCP_CHECK_TIMER(sk);
1119
1120         err = -ENOTCONN;
1121         if (sk->sk_state == TCP_LISTEN)
1122                 goto out;
1123
1124         timeo = sock_rcvtimeo(sk, nonblock);
1125
1126         /* Urgent data needs to be handled specially. */
1127         if (flags & MSG_OOB)
1128                 goto recv_urg;
1129
1130         seq = &tp->copied_seq;
1131         if (flags & MSG_PEEK) {
1132                 peek_seq = tp->copied_seq;
1133                 seq = &peek_seq;
1134         }
1135
1136         target = sock_rcvlowat(sk, flags & MSG_WAITALL, len);
1137
1138 #ifdef CONFIG_NET_DMA
1139         tp->ucopy.dma_chan = NULL;
1140         preempt_disable();
1141         if ((len > sysctl_tcp_dma_copybreak) && !(flags & MSG_PEEK) &&
1142             !sysctl_tcp_low_latency && __get_cpu_var(softnet_data).net_dma) {
1143                 preempt_enable_no_resched();
1144                 tp->ucopy.pinned_list = dma_pin_iovec_pages(msg->msg_iov, len);
1145         } else
1146                 preempt_enable_no_resched();
1147 #endif
1148
1149         do {
1150                 struct sk_buff *skb;
1151                 u32 offset;
1152
1153                 /* Are we at urgent data? Stop if we have read anything or have SIGURG pending. */
1154                 if (tp->urg_data && tp->urg_seq == *seq) {
1155                         if (copied)
1156                                 break;
1157                         if (signal_pending(current)) {
1158                                 copied = timeo ? sock_intr_errno(timeo) : -EAGAIN;
1159                                 break;
1160                         }
1161                 }
1162
1163                 /* Next get a buffer. */
1164
1165                 skb = skb_peek(&sk->sk_receive_queue);
1166                 do {
1167                         if (!skb)
1168                                 break;
1169
1170                         /* Now that we have two receive queues this
1171                          * shouldn't happen.
1172                          */
1173                         if (before(*seq, TCP_SKB_CB(skb)->seq)) {
1174                                 printk(KERN_INFO "recvmsg bug: copied %X "
1175                                        "seq %X\n", *seq, TCP_SKB_CB(skb)->seq);
1176                                 break;
1177                         }
1178                         offset = *seq - TCP_SKB_CB(skb)->seq;
1179                         if (tcp_hdr(skb)->syn)
1180                                 offset--;
1181                         if (offset < skb->len)
1182                                 goto found_ok_skb;
1183                         if (tcp_hdr(skb)->fin)
1184                                 goto found_fin_ok;
1185                         BUG_TRAP(flags & MSG_PEEK);
1186                         skb = skb->next;
1187                 } while (skb != (struct sk_buff *)&sk->sk_receive_queue);
1188
1189                 /* Well, if we have backlog, try to process it now yet. */
1190
1191                 if (copied >= target && !sk->sk_backlog.tail)
1192                         break;
1193
1194                 if (copied) {
1195                         if (sk->sk_err ||
1196                             sk->sk_state == TCP_CLOSE ||
1197                             (sk->sk_shutdown & RCV_SHUTDOWN) ||
1198                             !timeo ||
1199                             signal_pending(current) ||
1200                             (flags & MSG_PEEK))
1201                                 break;
1202                 } else {
1203                         if (sock_flag(sk, SOCK_DONE))
1204                                 break;
1205
1206                         if (sk->sk_err) {
1207                                 copied = sock_error(sk);
1208                                 break;
1209                         }
1210
1211                         if (sk->sk_shutdown & RCV_SHUTDOWN)
1212                                 break;
1213
1214                         if (sk->sk_state == TCP_CLOSE) {
1215                                 if (!sock_flag(sk, SOCK_DONE)) {
1216                                         /* This occurs when user tries to read
1217                                          * from never connected socket.
1218                                          */
1219                                         copied = -ENOTCONN;
1220                                         break;
1221                                 }
1222                                 break;
1223                         }
1224
1225                         if (!timeo) {
1226                                 copied = -EAGAIN;
1227                                 break;
1228                         }
1229
1230                         if (signal_pending(current)) {
1231                                 copied = sock_intr_errno(timeo);
1232                                 break;
1233                         }
1234                 }
1235
1236                 tcp_cleanup_rbuf(sk, copied);
1237
1238                 if (!sysctl_tcp_low_latency && tp->ucopy.task == user_recv) {
1239                         /* Install new reader */
1240                         if (!user_recv && !(flags & (MSG_TRUNC | MSG_PEEK))) {
1241                                 user_recv = current;
1242                                 tp->ucopy.task = user_recv;
1243                                 tp->ucopy.iov = msg->msg_iov;
1244                         }
1245
1246                         tp->ucopy.len = len;
1247
1248                         BUG_TRAP(tp->copied_seq == tp->rcv_nxt ||
1249                                  (flags & (MSG_PEEK | MSG_TRUNC)));
1250
1251                         /* Ugly... If prequeue is not empty, we have to
1252                          * process it before releasing socket, otherwise
1253                          * order will be broken at second iteration.
1254                          * More elegant solution is required!!!
1255                          *
1256                          * Look: we have the following (pseudo)queues:
1257                          *
1258                          * 1. packets in flight
1259                          * 2. backlog
1260                          * 3. prequeue
1261                          * 4. receive_queue
1262                          *
1263                          * Each queue can be processed only if the next ones
1264                          * are empty. At this point we have empty receive_queue.
1265                          * But prequeue _can_ be not empty after 2nd iteration,
1266                          * when we jumped to start of loop because backlog
1267                          * processing added something to receive_queue.
1268                          * We cannot release_sock(), because backlog contains
1269                          * packets arrived _after_ prequeued ones.
1270                          *
1271                          * Shortly, algorithm is clear --- to process all
1272                          * the queues in order. We could make it more directly,
1273                          * requeueing packets from backlog to prequeue, if
1274                          * is not empty. It is more elegant, but eats cycles,
1275                          * unfortunately.
1276                          */
1277                         if (!skb_queue_empty(&tp->ucopy.prequeue))
1278                                 goto do_prequeue;
1279
1280                         /* __ Set realtime policy in scheduler __ */
1281                 }
1282
1283                 if (copied >= target) {
1284                         /* Do not sleep, just process backlog. */
1285                         release_sock(sk);
1286                         lock_sock(sk);
1287                 } else
1288                         sk_wait_data(sk, &timeo);
1289
1290 #ifdef CONFIG_NET_DMA
1291                 tp->ucopy.wakeup = 0;
1292 #endif
1293
1294                 if (user_recv) {
1295                         int chunk;
1296
1297                         /* __ Restore normal policy in scheduler __ */
1298
1299                         if ((chunk = len - tp->ucopy.len) != 0) {
1300                                 NET_ADD_STATS_USER(LINUX_MIB_TCPDIRECTCOPYFROMBACKLOG, chunk);
1301                                 len -= chunk;
1302                                 copied += chunk;
1303                         }
1304
1305                         if (tp->rcv_nxt == tp->copied_seq &&
1306                             !skb_queue_empty(&tp->ucopy.prequeue)) {
1307 do_prequeue:
1308                                 tcp_prequeue_process(sk);
1309
1310                                 if ((chunk = len - tp->ucopy.len) != 0) {
1311                                         NET_ADD_STATS_USER(LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
1312                                         len -= chunk;
1313                                         copied += chunk;
1314                                 }
1315                         }
1316                 }
1317                 if ((flags & MSG_PEEK) && peek_seq != tp->copied_seq) {
1318                         if (net_ratelimit())
1319                                 printk(KERN_DEBUG "TCP(%s:%d): Application bug, race in MSG_PEEK.\n",
1320                                        current->comm, current->pid);
1321                         peek_seq = tp->copied_seq;
1322                 }
1323                 continue;
1324
1325         found_ok_skb:
1326                 /* Ok so how much can we use? */
1327                 used = skb->len - offset;
1328                 if (len < used)
1329                         used = len;
1330
1331                 /* Do we have urgent data here? */
1332                 if (tp->urg_data) {
1333                         u32 urg_offset = tp->urg_seq - *seq;
1334                         if (urg_offset < used) {
1335                                 if (!urg_offset) {
1336                                         if (!sock_flag(sk, SOCK_URGINLINE)) {
1337                                                 ++*seq;
1338                                                 offset++;
1339                                                 used--;
1340                                                 if (!used)
1341                                                         goto skip_copy;
1342                                         }
1343                                 } else
1344                                         used = urg_offset;
1345                         }
1346                 }
1347
1348                 if (!(flags & MSG_TRUNC)) {
1349 #ifdef CONFIG_NET_DMA
1350                         if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list)
1351                                 tp->ucopy.dma_chan = get_softnet_dma();
1352
1353                         if (tp->ucopy.dma_chan) {
1354                                 tp->ucopy.dma_cookie = dma_skb_copy_datagram_iovec(
1355                                         tp->ucopy.dma_chan, skb, offset,
1356                                         msg->msg_iov, used,
1357                                         tp->ucopy.pinned_list);
1358
1359                                 if (tp->ucopy.dma_cookie < 0) {
1360
1361                                         printk(KERN_ALERT "dma_cookie < 0\n");
1362
1363                                         /* Exception. Bailout! */
1364                                         if (!copied)
1365                                                 copied = -EFAULT;
1366                                         break;
1367                                 }
1368                                 if ((offset + used) == skb->len)
1369                                         copied_early = 1;
1370
1371                         } else
1372 #endif
1373                         {
1374                                 err = skb_copy_datagram_iovec(skb, offset,
1375                                                 msg->msg_iov, used);
1376                                 if (err) {
1377                                         /* Exception. Bailout! */
1378                                         if (!copied)
1379                                                 copied = -EFAULT;
1380                                         break;
1381                                 }
1382                         }
1383                 }
1384
1385                 *seq += used;
1386                 copied += used;
1387                 len -= used;
1388
1389                 tcp_rcv_space_adjust(sk);
1390
1391 skip_copy:
1392                 if (tp->urg_data && after(tp->copied_seq, tp->urg_seq)) {
1393                         tp->urg_data = 0;
1394                         tcp_fast_path_check(sk);
1395                 }
1396                 if (used + offset < skb->len)
1397                         continue;
1398
1399                 if (tcp_hdr(skb)->fin)
1400                         goto found_fin_ok;
1401                 if (!(flags & MSG_PEEK)) {
1402                         sk_eat_skb(sk, skb, copied_early);
1403                         copied_early = 0;
1404                 }
1405                 continue;
1406
1407         found_fin_ok:
1408                 /* Process the FIN. */
1409                 ++*seq;
1410                 if (!(flags & MSG_PEEK)) {
1411                         sk_eat_skb(sk, skb, copied_early);
1412                         copied_early = 0;
1413                 }
1414                 break;
1415         } while (len > 0);
1416
1417         if (user_recv) {
1418                 if (!skb_queue_empty(&tp->ucopy.prequeue)) {
1419                         int chunk;
1420
1421                         tp->ucopy.len = copied > 0 ? len : 0;
1422
1423                         tcp_prequeue_process(sk);
1424
1425                         if (copied > 0 && (chunk = len - tp->ucopy.len) != 0) {
1426                                 NET_ADD_STATS_USER(LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
1427                                 len -= chunk;
1428                                 copied += chunk;
1429                         }
1430                 }
1431
1432                 tp->ucopy.task = NULL;
1433                 tp->ucopy.len = 0;
1434         }
1435
1436 #ifdef CONFIG_NET_DMA
1437         if (tp->ucopy.dma_chan) {
1438                 struct sk_buff *skb;
1439                 dma_cookie_t done, used;
1440
1441                 dma_async_memcpy_issue_pending(tp->ucopy.dma_chan);
1442
1443                 while (dma_async_memcpy_complete(tp->ucopy.dma_chan,
1444                                                  tp->ucopy.dma_cookie, &done,
1445                                                  &used) == DMA_IN_PROGRESS) {
1446                         /* do partial cleanup of sk_async_wait_queue */
1447                         while ((skb = skb_peek(&sk->sk_async_wait_queue)) &&
1448                                (dma_async_is_complete(skb->dma_cookie, done,
1449                                                       used) == DMA_SUCCESS)) {
1450                                 __skb_dequeue(&sk->sk_async_wait_queue);
1451                                 kfree_skb(skb);
1452                         }
1453                 }
1454
1455                 /* Safe to free early-copied skbs now */
1456                 __skb_queue_purge(&sk->sk_async_wait_queue);
1457                 dma_chan_put(tp->ucopy.dma_chan);
1458                 tp->ucopy.dma_chan = NULL;
1459         }
1460         if (tp->ucopy.pinned_list) {
1461                 dma_unpin_iovec_pages(tp->ucopy.pinned_list);
1462                 tp->ucopy.pinned_list = NULL;
1463         }
1464 #endif
1465
1466         /* According to UNIX98, msg_name/msg_namelen are ignored
1467          * on connected socket. I was just happy when found this 8) --ANK
1468          */
1469
1470         /* Clean up data we have read: This will do ACK frames. */
1471         tcp_cleanup_rbuf(sk, copied);
1472
1473         TCP_CHECK_TIMER(sk);
1474         release_sock(sk);
1475         return copied;
1476
1477 out:
1478         TCP_CHECK_TIMER(sk);
1479         release_sock(sk);
1480         return err;
1481
1482 recv_urg:
1483         err = tcp_recv_urg(sk, timeo, msg, len, flags, addr_len);
1484         goto out;
1485 }
1486
1487 /*
1488  *      State processing on a close. This implements the state shift for
1489  *      sending our FIN frame. Note that we only send a FIN for some
1490  *      states. A shutdown() may have already sent the FIN, or we may be
1491  *      closed.
1492  */
1493
1494 static const unsigned char new_state[16] = {
1495   /* current state:        new state:      action:      */
1496   /* (Invalid)          */ TCP_CLOSE,
1497   /* TCP_ESTABLISHED    */ TCP_FIN_WAIT1 | TCP_ACTION_FIN,
1498   /* TCP_SYN_SENT       */ TCP_CLOSE,
1499   /* TCP_SYN_RECV       */ TCP_FIN_WAIT1 | TCP_ACTION_FIN,
1500   /* TCP_FIN_WAIT1      */ TCP_FIN_WAIT1,
1501   /* TCP_FIN_WAIT2      */ TCP_FIN_WAIT2,
1502   /* TCP_TIME_WAIT      */ TCP_CLOSE,
1503   /* TCP_CLOSE          */ TCP_CLOSE,
1504   /* TCP_CLOSE_WAIT     */ TCP_LAST_ACK  | TCP_ACTION_FIN,
1505   /* TCP_LAST_ACK       */ TCP_LAST_ACK,
1506   /* TCP_LISTEN         */ TCP_CLOSE,
1507   /* TCP_CLOSING        */ TCP_CLOSING,
1508 };
1509
1510 static int tcp_close_state(struct sock *sk)
1511 {
1512         int next = (int)new_state[sk->sk_state];
1513         int ns = next & TCP_STATE_MASK;
1514
1515         tcp_set_state(sk, ns);
1516
1517         return next & TCP_ACTION_FIN;
1518 }
1519
1520 /*
1521  *      Shutdown the sending side of a connection. Much like close except
1522  *      that we don't receive shut down or set_sock_flag(sk, SOCK_DEAD).
1523  */
1524
1525 void tcp_shutdown(struct sock *sk, int how)
1526 {
1527         /*      We need to grab some memory, and put together a FIN,
1528          *      and then put it into the queue to be sent.
1529          *              Tim MacKenzie(tym@dibbler.cs.monash.edu.au) 4 Dec '92.
1530          */
1531         if (!(how & SEND_SHUTDOWN))
1532                 return;
1533
1534         /* If we've already sent a FIN, or it's a closed state, skip this. */
1535         if ((1 << sk->sk_state) &
1536             (TCPF_ESTABLISHED | TCPF_SYN_SENT |
1537              TCPF_SYN_RECV | TCPF_CLOSE_WAIT)) {
1538                 /* Clear out any half completed packets.  FIN if needed. */
1539                 if (tcp_close_state(sk))
1540                         tcp_send_fin(sk);
1541         }
1542 }
1543
1544 void tcp_close(struct sock *sk, long timeout)
1545 {
1546         struct sk_buff *skb;
1547         int data_was_unread = 0;
1548         int state;
1549
1550         lock_sock(sk);
1551         sk->sk_shutdown = SHUTDOWN_MASK;
1552
1553         if (sk->sk_state == TCP_LISTEN) {
1554                 tcp_set_state(sk, TCP_CLOSE);
1555
1556                 /* Special case. */
1557                 inet_csk_listen_stop(sk);
1558
1559                 goto adjudge_to_death;
1560         }
1561
1562         /*  We need to flush the recv. buffs.  We do this only on the
1563          *  descriptor close, not protocol-sourced closes, because the
1564          *  reader process may not have drained the data yet!
1565          */
1566         while ((skb = __skb_dequeue(&sk->sk_receive_queue)) != NULL) {
1567                 u32 len = TCP_SKB_CB(skb)->end_seq - TCP_SKB_CB(skb)->seq -
1568                           tcp_hdr(skb)->fin;
1569                 data_was_unread += len;
1570                 __kfree_skb(skb);
1571         }
1572
1573         sk_stream_mem_reclaim(sk);
1574
1575         /* As outlined in RFC 2525, section 2.17, we send a RST here because
1576          * data was lost. To witness the awful effects of the old behavior of
1577          * always doing a FIN, run an older 2.1.x kernel or 2.0.x, start a bulk
1578          * GET in an FTP client, suspend the process, wait for the client to
1579          * advertise a zero window, then kill -9 the FTP client, wheee...
1580          * Note: timeout is always zero in such a case.
1581          */
1582         if (data_was_unread) {
1583                 /* Unread data was tossed, zap the connection. */
1584                 NET_INC_STATS_USER(LINUX_MIB_TCPABORTONCLOSE);
1585                 tcp_set_state(sk, TCP_CLOSE);
1586                 tcp_send_active_reset(sk, GFP_KERNEL);
1587         } else if (sock_flag(sk, SOCK_LINGER) && !sk->sk_lingertime) {
1588                 /* Check zero linger _after_ checking for unread data. */
1589                 sk->sk_prot->disconnect(sk, 0);
1590                 NET_INC_STATS_USER(LINUX_MIB_TCPABORTONDATA);
1591         } else if (tcp_close_state(sk)) {
1592                 /* We FIN if the application ate all the data before
1593                  * zapping the connection.
1594                  */
1595
1596                 /* RED-PEN. Formally speaking, we have broken TCP state
1597                  * machine. State transitions:
1598                  *
1599                  * TCP_ESTABLISHED -> TCP_FIN_WAIT1
1600                  * TCP_SYN_RECV -> TCP_FIN_WAIT1 (forget it, it's impossible)
1601                  * TCP_CLOSE_WAIT -> TCP_LAST_ACK
1602                  *
1603                  * are legal only when FIN has been sent (i.e. in window),
1604                  * rather than queued out of window. Purists blame.
1605                  *
1606                  * F.e. "RFC state" is ESTABLISHED,
1607                  * if Linux state is FIN-WAIT-1, but FIN is still not sent.
1608                  *
1609                  * The visible declinations are that sometimes
1610                  * we enter time-wait state, when it is not required really
1611                  * (harmless), do not send active resets, when they are
1612                  * required by specs (TCP_ESTABLISHED, TCP_CLOSE_WAIT, when
1613                  * they look as CLOSING or LAST_ACK for Linux)
1614                  * Probably, I missed some more holelets.
1615                  *                                              --ANK
1616                  */
1617                 tcp_send_fin(sk);
1618         }
1619
1620         sk_stream_wait_close(sk, timeout);
1621
1622 adjudge_to_death:
1623         state = sk->sk_state;
1624         sock_hold(sk);
1625         sock_orphan(sk);
1626         atomic_inc(sk->sk_prot->orphan_count);
1627
1628         /* It is the last release_sock in its life. It will remove backlog. */
1629         release_sock(sk);
1630
1631
1632         /* Now socket is owned by kernel and we acquire BH lock
1633            to finish close. No need to check for user refs.
1634          */
1635         local_bh_disable();
1636         bh_lock_sock(sk);
1637         BUG_TRAP(!sock_owned_by_user(sk));
1638
1639         /* Have we already been destroyed by a softirq or backlog? */
1640         if (state != TCP_CLOSE && sk->sk_state == TCP_CLOSE)
1641                 goto out;
1642
1643         /*      This is a (useful) BSD violating of the RFC. There is a
1644          *      problem with TCP as specified in that the other end could
1645          *      keep a socket open forever with no application left this end.
1646          *      We use a 3 minute timeout (about the same as BSD) then kill
1647          *      our end. If they send after that then tough - BUT: long enough
1648          *      that we won't make the old 4*rto = almost no time - whoops
1649          *      reset mistake.
1650          *
1651          *      Nope, it was not mistake. It is really desired behaviour
1652          *      f.e. on http servers, when such sockets are useless, but
1653          *      consume significant resources. Let's do it with special
1654          *      linger2 option.                                 --ANK
1655          */
1656
1657         if (sk->sk_state == TCP_FIN_WAIT2) {
1658                 struct tcp_sock *tp = tcp_sk(sk);
1659                 if (tp->linger2 < 0) {
1660                         tcp_set_state(sk, TCP_CLOSE);
1661                         tcp_send_active_reset(sk, GFP_ATOMIC);
1662                         NET_INC_STATS_BH(LINUX_MIB_TCPABORTONLINGER);
1663                 } else {
1664                         const int tmo = tcp_fin_time(sk);
1665
1666                         if (tmo > TCP_TIMEWAIT_LEN) {
1667                                 inet_csk_reset_keepalive_timer(sk,
1668                                                 tmo - TCP_TIMEWAIT_LEN);
1669                         } else {
1670                                 tcp_time_wait(sk, TCP_FIN_WAIT2, tmo);
1671                                 goto out;
1672                         }
1673                 }
1674         }
1675         if (sk->sk_state != TCP_CLOSE) {
1676                 sk_stream_mem_reclaim(sk);
1677                 if (tcp_too_many_orphans(sk,
1678                                 atomic_read(sk->sk_prot->orphan_count))) {
1679                         if (net_ratelimit())
1680                                 printk(KERN_INFO "TCP: too many of orphaned "
1681                                        "sockets\n");
1682                         tcp_set_state(sk, TCP_CLOSE);
1683                         tcp_send_active_reset(sk, GFP_ATOMIC);
1684                         NET_INC_STATS_BH(LINUX_MIB_TCPABORTONMEMORY);
1685                 }
1686         }
1687
1688         if (sk->sk_state == TCP_CLOSE)
1689                 inet_csk_destroy_sock(sk);
1690         /* Otherwise, socket is reprieved until protocol close. */
1691
1692 out:
1693         bh_unlock_sock(sk);
1694         local_bh_enable();
1695         sock_put(sk);
1696 }
1697
1698 /* These states need RST on ABORT according to RFC793 */
1699
1700 static inline int tcp_need_reset(int state)
1701 {
1702         return (1 << state) &
1703                (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT | TCPF_FIN_WAIT1 |
1704                 TCPF_FIN_WAIT2 | TCPF_SYN_RECV);
1705 }
1706
1707 int tcp_disconnect(struct sock *sk, int flags)
1708 {
1709         struct inet_sock *inet = inet_sk(sk);
1710         struct inet_connection_sock *icsk = inet_csk(sk);
1711         struct tcp_sock *tp = tcp_sk(sk);
1712         int err = 0;
1713         int old_state = sk->sk_state;
1714
1715         if (old_state != TCP_CLOSE)
1716                 tcp_set_state(sk, TCP_CLOSE);
1717
1718         /* ABORT function of RFC793 */
1719         if (old_state == TCP_LISTEN) {
1720                 inet_csk_listen_stop(sk);
1721         } else if (tcp_need_reset(old_state) ||
1722                    (tp->snd_nxt != tp->write_seq &&
1723                     (1 << old_state) & (TCPF_CLOSING | TCPF_LAST_ACK))) {
1724                 /* The last check adjusts for discrepancy of Linux wrt. RFC
1725                  * states
1726                  */
1727                 tcp_send_active_reset(sk, gfp_any());
1728                 sk->sk_err = ECONNRESET;
1729         } else if (old_state == TCP_SYN_SENT)
1730                 sk->sk_err = ECONNRESET;
1731
1732         tcp_clear_xmit_timers(sk);
1733         __skb_queue_purge(&sk->sk_receive_queue);
1734         tcp_write_queue_purge(sk);
1735         __skb_queue_purge(&tp->out_of_order_queue);
1736 #ifdef CONFIG_NET_DMA
1737         __skb_queue_purge(&sk->sk_async_wait_queue);
1738 #endif
1739
1740         inet->dport = 0;
1741
1742         if (!(sk->sk_userlocks & SOCK_BINDADDR_LOCK))
1743                 inet_reset_saddr(sk);
1744
1745         sk->sk_shutdown = 0;
1746         sock_reset_flag(sk, SOCK_DONE);
1747         tp->srtt = 0;
1748         if ((tp->write_seq += tp->max_window + 2) == 0)
1749                 tp->write_seq = 1;
1750         icsk->icsk_backoff = 0;
1751         tp->snd_cwnd = 2;
1752         icsk->icsk_probes_out = 0;
1753         tp->packets_out = 0;
1754         tp->snd_ssthresh = 0x7fffffff;
1755         tp->snd_cwnd_cnt = 0;
1756         tp->bytes_acked = 0;
1757         tcp_set_ca_state(sk, TCP_CA_Open);
1758         tcp_clear_retrans(tp);
1759         inet_csk_delack_init(sk);
1760         tcp_init_send_head(sk);
1761         memset(&tp->rx_opt, 0, sizeof(tp->rx_opt));
1762         __sk_dst_reset(sk);
1763
1764         BUG_TRAP(!inet->num || icsk->icsk_bind_hash);
1765
1766         sk->sk_error_report(sk);
1767         return err;
1768 }
1769
1770 /*
1771  *      Socket option code for TCP.
1772  */
1773 static int do_tcp_setsockopt(struct sock *sk, int level,
1774                 int optname, char __user *optval, int optlen)
1775 {
1776         struct tcp_sock *tp = tcp_sk(sk);
1777         struct inet_connection_sock *icsk = inet_csk(sk);
1778         int val;
1779         int err = 0;
1780
1781         /* This is a string value all the others are int's */
1782         if (optname == TCP_CONGESTION) {
1783                 char name[TCP_CA_NAME_MAX];
1784
1785                 if (optlen < 1)
1786                         return -EINVAL;
1787
1788                 val = strncpy_from_user(name, optval,
1789                                         min(TCP_CA_NAME_MAX-1, optlen));
1790                 if (val < 0)
1791                         return -EFAULT;
1792                 name[val] = 0;
1793
1794                 lock_sock(sk);
1795                 err = tcp_set_congestion_control(sk, name);
1796                 release_sock(sk);
1797                 return err;
1798         }
1799
1800         if (optlen < sizeof(int))
1801                 return -EINVAL;
1802
1803         if (get_user(val, (int __user *)optval))
1804                 return -EFAULT;
1805
1806         lock_sock(sk);
1807
1808         switch (optname) {
1809         case TCP_MAXSEG:
1810                 /* Values greater than interface MTU won't take effect. However
1811                  * at the point when this call is done we typically don't yet
1812                  * know which interface is going to be used */
1813                 if (val < 8 || val > MAX_TCP_WINDOW) {
1814                         err = -EINVAL;
1815                         break;
1816                 }
1817                 tp->rx_opt.user_mss = val;
1818                 break;
1819
1820         case TCP_NODELAY:
1821                 if (val) {
1822                         /* TCP_NODELAY is weaker than TCP_CORK, so that
1823                          * this option on corked socket is remembered, but
1824                          * it is not activated until cork is cleared.
1825                          *
1826                          * However, when TCP_NODELAY is set we make
1827                          * an explicit push, which overrides even TCP_CORK
1828                          * for currently queued segments.
1829                          */
1830                         tp->nonagle |= TCP_NAGLE_OFF|TCP_NAGLE_PUSH;
1831                         tcp_push_pending_frames(sk);
1832                 } else {
1833                         tp->nonagle &= ~TCP_NAGLE_OFF;
1834                 }
1835                 break;
1836
1837         case TCP_CORK:
1838                 /* When set indicates to always queue non-full frames.
1839                  * Later the user clears this option and we transmit
1840                  * any pending partial frames in the queue.  This is
1841                  * meant to be used alongside sendfile() to get properly
1842                  * filled frames when the user (for example) must write
1843                  * out headers with a write() call first and then use
1844                  * sendfile to send out the data parts.
1845                  *
1846                  * TCP_CORK can be set together with TCP_NODELAY and it is
1847                  * stronger than TCP_NODELAY.
1848                  */
1849                 if (val) {
1850                         tp->nonagle |= TCP_NAGLE_CORK;
1851                 } else {
1852                         tp->nonagle &= ~TCP_NAGLE_CORK;
1853                         if (tp->nonagle&TCP_NAGLE_OFF)
1854                                 tp->nonagle |= TCP_NAGLE_PUSH;
1855                         tcp_push_pending_frames(sk);
1856                 }
1857                 break;
1858
1859         case TCP_KEEPIDLE:
1860                 if (val < 1 || val > MAX_TCP_KEEPIDLE)
1861                         err = -EINVAL;
1862                 else {
1863                         tp->keepalive_time = val * HZ;
1864                         if (sock_flag(sk, SOCK_KEEPOPEN) &&
1865                             !((1 << sk->sk_state) &
1866                               (TCPF_CLOSE | TCPF_LISTEN))) {
1867                                 __u32 elapsed = tcp_time_stamp - tp->rcv_tstamp;
1868                                 if (tp->keepalive_time > elapsed)
1869                                         elapsed = tp->keepalive_time - elapsed;
1870                                 else
1871                                         elapsed = 0;
1872                                 inet_csk_reset_keepalive_timer(sk, elapsed);
1873                         }
1874                 }
1875                 break;
1876         case TCP_KEEPINTVL:
1877                 if (val < 1 || val > MAX_TCP_KEEPINTVL)
1878                         err = -EINVAL;
1879                 else
1880                         tp->keepalive_intvl = val * HZ;
1881                 break;
1882         case TCP_KEEPCNT:
1883                 if (val < 1 || val > MAX_TCP_KEEPCNT)
1884                         err = -EINVAL;
1885                 else
1886                         tp->keepalive_probes = val;
1887                 break;
1888         case TCP_SYNCNT:
1889                 if (val < 1 || val > MAX_TCP_SYNCNT)
1890                         err = -EINVAL;
1891                 else
1892                         icsk->icsk_syn_retries = val;
1893                 break;
1894
1895         case TCP_LINGER2:
1896                 if (val < 0)
1897                         tp->linger2 = -1;
1898                 else if (val > sysctl_tcp_fin_timeout / HZ)
1899                         tp->linger2 = 0;
1900                 else
1901                         tp->linger2 = val * HZ;
1902                 break;
1903
1904         case TCP_DEFER_ACCEPT:
1905                 icsk->icsk_accept_queue.rskq_defer_accept = 0;
1906                 if (val > 0) {
1907                         /* Translate value in seconds to number of
1908                          * retransmits */
1909                         while (icsk->icsk_accept_queue.rskq_defer_accept < 32 &&
1910                                val > ((TCP_TIMEOUT_INIT / HZ) <<
1911                                        icsk->icsk_accept_queue.rskq_defer_accept))
1912                                 icsk->icsk_accept_queue.rskq_defer_accept++;
1913                         icsk->icsk_accept_queue.rskq_defer_accept++;
1914                 }
1915                 break;
1916
1917         case TCP_WINDOW_CLAMP:
1918                 if (!val) {
1919                         if (sk->sk_state != TCP_CLOSE) {
1920                                 err = -EINVAL;
1921                                 break;
1922                         }
1923                         tp->window_clamp = 0;
1924                 } else
1925                         tp->window_clamp = val < SOCK_MIN_RCVBUF / 2 ?
1926                                                 SOCK_MIN_RCVBUF / 2 : val;
1927                 break;
1928
1929         case TCP_QUICKACK:
1930                 if (!val) {
1931                         icsk->icsk_ack.pingpong = 1;
1932                 } else {
1933                         icsk->icsk_ack.pingpong = 0;
1934                         if ((1 << sk->sk_state) &
1935                             (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT) &&
1936                             inet_csk_ack_scheduled(sk)) {
1937                                 icsk->icsk_ack.pending |= ICSK_ACK_PUSHED;
1938                                 tcp_cleanup_rbuf(sk, 1);
1939                                 if (!(val & 1))
1940                                         icsk->icsk_ack.pingpong = 1;
1941                         }
1942                 }
1943                 break;
1944
1945 #ifdef CONFIG_TCP_MD5SIG
1946         case TCP_MD5SIG:
1947                 /* Read the IP->Key mappings from userspace */
1948                 err = tp->af_specific->md5_parse(sk, optval, optlen);
1949                 break;
1950 #endif
1951
1952         default:
1953                 err = -ENOPROTOOPT;
1954                 break;
1955         }
1956
1957         release_sock(sk);
1958         return err;
1959 }
1960
1961 int tcp_setsockopt(struct sock *sk, int level, int optname, char __user *optval,
1962                    int optlen)
1963 {
1964         struct inet_connection_sock *icsk = inet_csk(sk);
1965
1966         if (level != SOL_TCP)
1967                 return icsk->icsk_af_ops->setsockopt(sk, level, optname,
1968                                                      optval, optlen);
1969         return do_tcp_setsockopt(sk, level, optname, optval, optlen);
1970 }
1971
1972 #ifdef CONFIG_COMPAT
1973 int compat_tcp_setsockopt(struct sock *sk, int level, int optname,
1974                           char __user *optval, int optlen)
1975 {
1976         if (level != SOL_TCP)
1977                 return inet_csk_compat_setsockopt(sk, level, optname,
1978                                                   optval, optlen);
1979         return do_tcp_setsockopt(sk, level, optname, optval, optlen);
1980 }
1981
1982 EXPORT_SYMBOL(compat_tcp_setsockopt);
1983 #endif
1984
1985 /* Return information about state of tcp endpoint in API format. */
1986 void tcp_get_info(struct sock *sk, struct tcp_info *info)
1987 {
1988         struct tcp_sock *tp = tcp_sk(sk);
1989         const struct inet_connection_sock *icsk = inet_csk(sk);
1990         u32 now = tcp_time_stamp;
1991
1992         memset(info, 0, sizeof(*info));
1993
1994         info->tcpi_state = sk->sk_state;
1995         info->tcpi_ca_state = icsk->icsk_ca_state;
1996         info->tcpi_retransmits = icsk->icsk_retransmits;
1997         info->tcpi_probes = icsk->icsk_probes_out;
1998         info->tcpi_backoff = icsk->icsk_backoff;
1999
2000         if (tp->rx_opt.tstamp_ok)
2001                 info->tcpi_options |= TCPI_OPT_TIMESTAMPS;
2002         if (tp->rx_opt.sack_ok)
2003                 info->tcpi_options |= TCPI_OPT_SACK;
2004         if (tp->rx_opt.wscale_ok) {
2005                 info->tcpi_options |= TCPI_OPT_WSCALE;
2006                 info->tcpi_snd_wscale = tp->rx_opt.snd_wscale;
2007                 info->tcpi_rcv_wscale = tp->rx_opt.rcv_wscale;
2008         }
2009
2010         if (tp->ecn_flags&TCP_ECN_OK)
2011                 info->tcpi_options |= TCPI_OPT_ECN;
2012
2013         info->tcpi_rto = jiffies_to_usecs(icsk->icsk_rto);
2014         info->tcpi_ato = jiffies_to_usecs(icsk->icsk_ack.ato);
2015         info->tcpi_snd_mss = tp->mss_cache;
2016         info->tcpi_rcv_mss = icsk->icsk_ack.rcv_mss;
2017
2018         info->tcpi_unacked = tp->packets_out;
2019         info->tcpi_sacked = tp->sacked_out;
2020         info->tcpi_lost = tp->lost_out;
2021         info->tcpi_retrans = tp->retrans_out;
2022         info->tcpi_fackets = tp->fackets_out;
2023
2024         info->tcpi_last_data_sent = jiffies_to_msecs(now - tp->lsndtime);
2025         info->tcpi_last_data_recv = jiffies_to_msecs(now - icsk->icsk_ack.lrcvtime);
2026         info->tcpi_last_ack_recv = jiffies_to_msecs(now - tp->rcv_tstamp);
2027
2028         info->tcpi_pmtu = icsk->icsk_pmtu_cookie;
2029         info->tcpi_rcv_ssthresh = tp->rcv_ssthresh;
2030         info->tcpi_rtt = jiffies_to_usecs(tp->srtt)>>3;
2031         info->tcpi_rttvar = jiffies_to_usecs(tp->mdev)>>2;
2032         info->tcpi_snd_ssthresh = tp->snd_ssthresh;
2033         info->tcpi_snd_cwnd = tp->snd_cwnd;
2034         info->tcpi_advmss = tp->advmss;
2035         info->tcpi_reordering = tp->reordering;
2036
2037         info->tcpi_rcv_rtt = jiffies_to_usecs(tp->rcv_rtt_est.rtt)>>3;
2038         info->tcpi_rcv_space = tp->rcvq_space.space;
2039
2040         info->tcpi_total_retrans = tp->total_retrans;
2041 }
2042
2043 EXPORT_SYMBOL_GPL(tcp_get_info);
2044
2045 static int do_tcp_getsockopt(struct sock *sk, int level,
2046                 int optname, char __user *optval, int __user *optlen)
2047 {
2048         struct inet_connection_sock *icsk = inet_csk(sk);
2049         struct tcp_sock *tp = tcp_sk(sk);
2050         int val, len;
2051
2052         if (get_user(len, optlen))
2053                 return -EFAULT;
2054
2055         len = min_t(unsigned int, len, sizeof(int));
2056
2057         if (len < 0)
2058                 return -EINVAL;
2059
2060         switch (optname) {
2061         case TCP_MAXSEG:
2062                 val = tp->mss_cache;
2063                 if (!val && ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN)))
2064                         val = tp->rx_opt.user_mss;
2065                 break;
2066         case TCP_NODELAY:
2067                 val = !!(tp->nonagle&TCP_NAGLE_OFF);
2068                 break;
2069         case TCP_CORK:
2070                 val = !!(tp->nonagle&TCP_NAGLE_CORK);
2071                 break;
2072         case TCP_KEEPIDLE:
2073                 val = (tp->keepalive_time ? : sysctl_tcp_keepalive_time) / HZ;
2074                 break;
2075         case TCP_KEEPINTVL:
2076                 val = (tp->keepalive_intvl ? : sysctl_tcp_keepalive_intvl) / HZ;
2077                 break;
2078         case TCP_KEEPCNT:
2079                 val = tp->keepalive_probes ? : sysctl_tcp_keepalive_probes;
2080                 break;
2081         case TCP_SYNCNT:
2082                 val = icsk->icsk_syn_retries ? : sysctl_tcp_syn_retries;
2083                 break;
2084         case TCP_LINGER2:
2085                 val = tp->linger2;
2086                 if (val >= 0)
2087                         val = (val ? : sysctl_tcp_fin_timeout) / HZ;
2088                 break;
2089         case TCP_DEFER_ACCEPT:
2090                 val = !icsk->icsk_accept_queue.rskq_defer_accept ? 0 :
2091                         ((TCP_TIMEOUT_INIT / HZ) << (icsk->icsk_accept_queue.rskq_defer_accept - 1));
2092                 break;
2093         case TCP_WINDOW_CLAMP:
2094                 val = tp->window_clamp;
2095                 break;
2096         case TCP_INFO: {
2097                 struct tcp_info info;
2098
2099                 if (get_user(len, optlen))
2100                         return -EFAULT;
2101
2102                 tcp_get_info(sk, &info);
2103
2104                 len = min_t(unsigned int, len, sizeof(info));
2105                 if (put_user(len, optlen))
2106                         return -EFAULT;
2107                 if (copy_to_user(optval, &info, len))
2108                         return -EFAULT;
2109                 return 0;
2110         }
2111         case TCP_QUICKACK:
2112                 val = !icsk->icsk_ack.pingpong;
2113                 break;
2114
2115         case TCP_CONGESTION:
2116                 if (get_user(len, optlen))
2117                         return -EFAULT;
2118                 len = min_t(unsigned int, len, TCP_CA_NAME_MAX);
2119                 if (put_user(len, optlen))
2120                         return -EFAULT;
2121                 if (copy_to_user(optval, icsk->icsk_ca_ops->name, len))
2122                         return -EFAULT;
2123                 return 0;
2124         default:
2125                 return -ENOPROTOOPT;
2126         }
2127
2128         if (put_user(len, optlen))
2129                 return -EFAULT;
2130         if (copy_to_user(optval, &val, len))
2131                 return -EFAULT;
2132         return 0;
2133 }
2134
2135 int tcp_getsockopt(struct sock *sk, int level, int optname, char __user *optval,
2136                    int __user *optlen)
2137 {
2138         struct inet_connection_sock *icsk = inet_csk(sk);
2139
2140         if (level != SOL_TCP)
2141                 return icsk->icsk_af_ops->getsockopt(sk, level, optname,
2142                                                      optval, optlen);
2143         return do_tcp_getsockopt(sk, level, optname, optval, optlen);
2144 }
2145
2146 #ifdef CONFIG_COMPAT
2147 int compat_tcp_getsockopt(struct sock *sk, int level, int optname,
2148                           char __user *optval, int __user *optlen)
2149 {
2150         if (level != SOL_TCP)
2151                 return inet_csk_compat_getsockopt(sk, level, optname,
2152                                                   optval, optlen);
2153         return do_tcp_getsockopt(sk, level, optname, optval, optlen);
2154 }
2155
2156 EXPORT_SYMBOL(compat_tcp_getsockopt);
2157 #endif
2158
2159 struct sk_buff *tcp_tso_segment(struct sk_buff *skb, int features)
2160 {
2161         struct sk_buff *segs = ERR_PTR(-EINVAL);
2162         struct tcphdr *th;
2163         unsigned thlen;
2164         unsigned int seq;
2165         __be32 delta;
2166         unsigned int oldlen;
2167         unsigned int len;
2168
2169         if (!pskb_may_pull(skb, sizeof(*th)))
2170                 goto out;
2171
2172         th = tcp_hdr(skb);
2173         thlen = th->doff * 4;
2174         if (thlen < sizeof(*th))
2175                 goto out;
2176
2177         if (!pskb_may_pull(skb, thlen))
2178                 goto out;
2179
2180         oldlen = (u16)~skb->len;
2181         __skb_pull(skb, thlen);
2182
2183         if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) {
2184                 /* Packet is from an untrusted source, reset gso_segs. */
2185                 int type = skb_shinfo(skb)->gso_type;
2186                 int mss;
2187
2188                 if (unlikely(type &
2189                              ~(SKB_GSO_TCPV4 |
2190                                SKB_GSO_DODGY |
2191                                SKB_GSO_TCP_ECN |
2192                                SKB_GSO_TCPV6 |
2193                                0) ||
2194                              !(type & (SKB_GSO_TCPV4 | SKB_GSO_TCPV6))))
2195                         goto out;
2196
2197                 mss = skb_shinfo(skb)->gso_size;
2198                 skb_shinfo(skb)->gso_segs = (skb->len + mss - 1) / mss;
2199
2200                 segs = NULL;
2201                 goto out;
2202         }
2203
2204         segs = skb_segment(skb, features);
2205         if (IS_ERR(segs))
2206                 goto out;
2207
2208         len = skb_shinfo(skb)->gso_size;
2209         delta = htonl(oldlen + (thlen + len));
2210
2211         skb = segs;
2212         th = tcp_hdr(skb);
2213         seq = ntohl(th->seq);
2214
2215         do {
2216                 th->fin = th->psh = 0;
2217
2218                 th->check = ~csum_fold((__force __wsum)((__force u32)th->check +
2219                                        (__force u32)delta));
2220                 if (skb->ip_summed != CHECKSUM_PARTIAL)
2221                         th->check =
2222                              csum_fold(csum_partial(skb_transport_header(skb),
2223                                                     thlen, skb->csum));
2224
2225                 seq += len;
2226                 skb = skb->next;
2227                 th = tcp_hdr(skb);
2228
2229                 th->seq = htonl(seq);
2230                 th->cwr = 0;
2231         } while (skb->next);
2232
2233         delta = htonl(oldlen + (skb->tail - skb->transport_header) +
2234                       skb->data_len);
2235         th->check = ~csum_fold((__force __wsum)((__force u32)th->check +
2236                                 (__force u32)delta));
2237         if (skb->ip_summed != CHECKSUM_PARTIAL)
2238                 th->check = csum_fold(csum_partial(skb_transport_header(skb),
2239                                                    thlen, skb->csum));
2240
2241 out:
2242         return segs;
2243 }
2244 EXPORT_SYMBOL(tcp_tso_segment);
2245
2246 #ifdef CONFIG_TCP_MD5SIG
2247 static unsigned long tcp_md5sig_users;
2248 static struct tcp_md5sig_pool **tcp_md5sig_pool;
2249 static DEFINE_SPINLOCK(tcp_md5sig_pool_lock);
2250
2251 static void __tcp_free_md5sig_pool(struct tcp_md5sig_pool **pool)
2252 {
2253         int cpu;
2254         for_each_possible_cpu(cpu) {
2255                 struct tcp_md5sig_pool *p = *per_cpu_ptr(pool, cpu);
2256                 if (p) {
2257                         if (p->md5_desc.tfm)
2258                                 crypto_free_hash(p->md5_desc.tfm);
2259                         kfree(p);
2260                         p = NULL;
2261                 }
2262         }
2263         free_percpu(pool);
2264 }
2265
2266 void tcp_free_md5sig_pool(void)
2267 {
2268         struct tcp_md5sig_pool **pool = NULL;
2269
2270         spin_lock_bh(&tcp_md5sig_pool_lock);
2271         if (--tcp_md5sig_users == 0) {
2272                 pool = tcp_md5sig_pool;
2273                 tcp_md5sig_pool = NULL;
2274         }
2275         spin_unlock_bh(&tcp_md5sig_pool_lock);
2276         if (pool)
2277                 __tcp_free_md5sig_pool(pool);
2278 }
2279
2280 EXPORT_SYMBOL(tcp_free_md5sig_pool);
2281
2282 static struct tcp_md5sig_pool **__tcp_alloc_md5sig_pool(void)
2283 {
2284         int cpu;
2285         struct tcp_md5sig_pool **pool;
2286
2287         pool = alloc_percpu(struct tcp_md5sig_pool *);
2288         if (!pool)
2289                 return NULL;
2290
2291         for_each_possible_cpu(cpu) {
2292                 struct tcp_md5sig_pool *p;
2293                 struct crypto_hash *hash;
2294
2295                 p = kzalloc(sizeof(*p), GFP_KERNEL);
2296                 if (!p)
2297                         goto out_free;
2298                 *per_cpu_ptr(pool, cpu) = p;
2299
2300                 hash = crypto_alloc_hash("md5", 0, CRYPTO_ALG_ASYNC);
2301                 if (!hash || IS_ERR(hash))
2302                         goto out_free;
2303
2304                 p->md5_desc.tfm = hash;
2305         }
2306         return pool;
2307 out_free:
2308         __tcp_free_md5sig_pool(pool);
2309         return NULL;
2310 }
2311
2312 struct tcp_md5sig_pool **tcp_alloc_md5sig_pool(void)
2313 {
2314         struct tcp_md5sig_pool **pool;
2315         int alloc = 0;
2316
2317 retry:
2318         spin_lock_bh(&tcp_md5sig_pool_lock);
2319         pool = tcp_md5sig_pool;
2320         if (tcp_md5sig_users++ == 0) {
2321                 alloc = 1;
2322                 spin_unlock_bh(&tcp_md5sig_pool_lock);
2323         } else if (!pool) {
2324                 tcp_md5sig_users--;
2325                 spin_unlock_bh(&tcp_md5sig_pool_lock);
2326                 cpu_relax();
2327                 goto retry;
2328         } else
2329                 spin_unlock_bh(&tcp_md5sig_pool_lock);
2330
2331         if (alloc) {
2332                 /* we cannot hold spinlock here because this may sleep. */
2333                 struct tcp_md5sig_pool **p = __tcp_alloc_md5sig_pool();
2334                 spin_lock_bh(&tcp_md5sig_pool_lock);
2335                 if (!p) {
2336                         tcp_md5sig_users--;
2337                         spin_unlock_bh(&tcp_md5sig_pool_lock);
2338                         return NULL;
2339                 }
2340                 pool = tcp_md5sig_pool;
2341                 if (pool) {
2342                         /* oops, it has already been assigned. */
2343                         spin_unlock_bh(&tcp_md5sig_pool_lock);
2344                         __tcp_free_md5sig_pool(p);
2345                 } else {
2346                         tcp_md5sig_pool = pool = p;
2347                         spin_unlock_bh(&tcp_md5sig_pool_lock);
2348                 }
2349         }
2350         return pool;
2351 }
2352
2353 EXPORT_SYMBOL(tcp_alloc_md5sig_pool);
2354
2355 struct tcp_md5sig_pool *__tcp_get_md5sig_pool(int cpu)
2356 {
2357         struct tcp_md5sig_pool **p;
2358         spin_lock_bh(&tcp_md5sig_pool_lock);
2359         p = tcp_md5sig_pool;
2360         if (p)
2361                 tcp_md5sig_users++;
2362         spin_unlock_bh(&tcp_md5sig_pool_lock);
2363         return (p ? *per_cpu_ptr(p, cpu) : NULL);
2364 }
2365
2366 EXPORT_SYMBOL(__tcp_get_md5sig_pool);
2367
2368 void __tcp_put_md5sig_pool(void)
2369 {
2370         tcp_free_md5sig_pool();
2371 }
2372
2373 EXPORT_SYMBOL(__tcp_put_md5sig_pool);
2374 #endif
2375
2376 void tcp_done(struct sock *sk)
2377 {
2378         if(sk->sk_state == TCP_SYN_SENT || sk->sk_state == TCP_SYN_RECV)
2379                 TCP_INC_STATS_BH(TCP_MIB_ATTEMPTFAILS);
2380
2381         tcp_set_state(sk, TCP_CLOSE);
2382         tcp_clear_xmit_timers(sk);
2383
2384         sk->sk_shutdown = SHUTDOWN_MASK;
2385
2386         if (!sock_flag(sk, SOCK_DEAD))
2387                 sk->sk_state_change(sk);
2388         else
2389                 inet_csk_destroy_sock(sk);
2390 }
2391 EXPORT_SYMBOL_GPL(tcp_done);
2392
2393 extern void __skb_cb_too_small_for_tcp(int, int);
2394 extern struct tcp_congestion_ops tcp_reno;
2395
2396 static __initdata unsigned long thash_entries;
2397 static int __init set_thash_entries(char *str)
2398 {
2399         if (!str)
2400                 return 0;
2401         thash_entries = simple_strtoul(str, &str, 0);
2402         return 1;
2403 }
2404 __setup("thash_entries=", set_thash_entries);
2405
2406 void __init tcp_init(void)
2407 {
2408         struct sk_buff *skb = NULL;
2409         unsigned long limit;
2410         int order, i, max_share;
2411
2412         if (sizeof(struct tcp_skb_cb) > sizeof(skb->cb))
2413                 __skb_cb_too_small_for_tcp(sizeof(struct tcp_skb_cb),
2414                                            sizeof(skb->cb));
2415
2416         tcp_hashinfo.bind_bucket_cachep =
2417                 kmem_cache_create("tcp_bind_bucket",
2418                                   sizeof(struct inet_bind_bucket), 0,
2419                                   SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL);
2420
2421         /* Size and allocate the main established and bind bucket
2422          * hash tables.
2423          *
2424          * The methodology is similar to that of the buffer cache.
2425          */
2426         tcp_hashinfo.ehash =
2427                 alloc_large_system_hash("TCP established",
2428                                         sizeof(struct inet_ehash_bucket),
2429                                         thash_entries,
2430                                         (num_physpages >= 128 * 1024) ?
2431                                         13 : 15,
2432                                         0,
2433                                         &tcp_hashinfo.ehash_size,
2434                                         NULL,
2435                                         0);
2436         tcp_hashinfo.ehash_size = 1 << tcp_hashinfo.ehash_size;
2437         for (i = 0; i < tcp_hashinfo.ehash_size; i++) {
2438                 rwlock_init(&tcp_hashinfo.ehash[i].lock);
2439                 INIT_HLIST_HEAD(&tcp_hashinfo.ehash[i].chain);
2440                 INIT_HLIST_HEAD(&tcp_hashinfo.ehash[i].twchain);
2441         }
2442
2443         tcp_hashinfo.bhash =
2444                 alloc_large_system_hash("TCP bind",
2445                                         sizeof(struct inet_bind_hashbucket),
2446                                         tcp_hashinfo.ehash_size,
2447                                         (num_physpages >= 128 * 1024) ?
2448                                         13 : 15,
2449                                         0,
2450                                         &tcp_hashinfo.bhash_size,
2451                                         NULL,
2452                                         64 * 1024);
2453         tcp_hashinfo.bhash_size = 1 << tcp_hashinfo.bhash_size;
2454         for (i = 0; i < tcp_hashinfo.bhash_size; i++) {
2455                 spin_lock_init(&tcp_hashinfo.bhash[i].lock);
2456                 INIT_HLIST_HEAD(&tcp_hashinfo.bhash[i].chain);
2457         }
2458
2459         /* Try to be a bit smarter and adjust defaults depending
2460          * on available memory.
2461          */
2462         for (order = 0; ((1 << order) << PAGE_SHIFT) <
2463                         (tcp_hashinfo.bhash_size * sizeof(struct inet_bind_hashbucket));
2464                         order++)
2465                 ;
2466         if (order >= 4) {
2467                 tcp_death_row.sysctl_max_tw_buckets = 180000;
2468                 sysctl_tcp_max_orphans = 4096 << (order - 4);
2469                 sysctl_max_syn_backlog = 1024;
2470         } else if (order < 3) {
2471                 tcp_death_row.sysctl_max_tw_buckets >>= (3 - order);
2472                 sysctl_tcp_max_orphans >>= (3 - order);
2473                 sysctl_max_syn_backlog = 128;
2474         }
2475
2476         /* Set the pressure threshold to be a fraction of global memory that
2477          * is up to 1/2 at 256 MB, decreasing toward zero with the amount of
2478          * memory, with a floor of 128 pages.
2479          */
2480         limit = min(nr_all_pages, 1UL<<(28-PAGE_SHIFT)) >> (20-PAGE_SHIFT);
2481         limit = (limit * (nr_all_pages >> (20-PAGE_SHIFT))) >> (PAGE_SHIFT-11);
2482         limit = max(limit, 128UL);
2483         sysctl_tcp_mem[0] = limit / 4 * 3;
2484         sysctl_tcp_mem[1] = limit;
2485         sysctl_tcp_mem[2] = sysctl_tcp_mem[0] * 2;
2486
2487         /* Set per-socket limits to no more than 1/128 the pressure threshold */
2488         limit = ((unsigned long)sysctl_tcp_mem[1]) << (PAGE_SHIFT - 7);
2489         max_share = min(4UL*1024*1024, limit);
2490
2491         sysctl_tcp_wmem[0] = SK_STREAM_MEM_QUANTUM;
2492         sysctl_tcp_wmem[1] = 16*1024;
2493         sysctl_tcp_wmem[2] = max(64*1024, max_share);
2494
2495         sysctl_tcp_rmem[0] = SK_STREAM_MEM_QUANTUM;
2496         sysctl_tcp_rmem[1] = 87380;
2497         sysctl_tcp_rmem[2] = max(87380, max_share);
2498
2499         printk(KERN_INFO "TCP: Hash tables configured "
2500                "(established %d bind %d)\n",
2501                tcp_hashinfo.ehash_size, tcp_hashinfo.bhash_size);
2502
2503         tcp_register_congestion_control(&tcp_reno);
2504 }
2505
2506 EXPORT_SYMBOL(tcp_close);
2507 EXPORT_SYMBOL(tcp_disconnect);
2508 EXPORT_SYMBOL(tcp_getsockopt);
2509 EXPORT_SYMBOL(tcp_ioctl);
2510 EXPORT_SYMBOL(tcp_poll);
2511 EXPORT_SYMBOL(tcp_read_sock);
2512 EXPORT_SYMBOL(tcp_recvmsg);
2513 EXPORT_SYMBOL(tcp_sendmsg);
2514 EXPORT_SYMBOL(tcp_sendpage);
2515 EXPORT_SYMBOL(tcp_setsockopt);
2516 EXPORT_SYMBOL(tcp_shutdown);
2517 EXPORT_SYMBOL(tcp_statistics);