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/smp_lock.h>
 256 #include <linux/fs.h>
 257 #include <linux/random.h>
 258 #include <linux/bootmem.h>
 259 #include <linux/cache.h>
 260 #include <linux/err.h>
 261 #include <linux/crypto.h>
 262
 263 #include <net/icmp.h>
 264 #include <net/tcp.h>
 265 #include <net/xfrm.h>
 266 #include <net/ip.h>
 267 #include <net/netdma.h>
 268
 269 #include <asm/uaccess.h>
 270 #include <asm/ioctls.h>
 271
 272 int sysctl_tcp_fin_timeout __read_mostly = TCP_FIN_TIMEOUT;
 273
 274 DEFINE_SNMP_STAT(struct tcp_mib, tcp_statistics) __read_mostly;
 275
 276 atomic_t tcp_orphan_count = ATOMIC_INIT(0);
 277
 278 EXPORT_SYMBOL_GPL(tcp_orphan_count);
 279
 280 int sysctl_tcp_mem[3] __read_mostly;
 281 int sysctl_tcp_wmem[3] __read_mostly;
 282 int sysctl_tcp_rmem[3] __read_mostly;
 283
 284 EXPORT_SYMBOL(sysctl_tcp_mem);
 285 EXPORT_SYMBOL(sysctl_tcp_rmem);
 286 EXPORT_SYMBOL(sysctl_tcp_wmem);
 287
 288 atomic_t tcp_memory_allocated;  /* Current allocated memory. */
 289 atomic_t tcp_sockets_allocated; /* Current number of TCP sockets. */
 290
 291 EXPORT_SYMBOL(tcp_memory_allocated);
 292 EXPORT_SYMBOL(tcp_sockets_allocated);
 293
 294 /*
 295  * Pressure flag: try to collapse.
 296  * Technical note: it is used by multiple contexts non atomically.
 297  * All the sk_stream_mem_schedule() is of this nature: accounting
 298  * is strict, actions are advisory and have some latency.
 299  */
 300 int tcp_memory_pressure __read_mostly;
 301
 302 EXPORT_SYMBOL(tcp_memory_pressure);
 303
 304 void tcp_enter_memory_pressure(void)
 305 {
 306         if (!tcp_memory_pressure) {
 307                 NET_INC_STATS(LINUX_MIB_TCPMEMORYPRESSURES);
 308                 tcp_memory_pressure = 1;
 309         }
 310 }
 311
 312 EXPORT_SYMBOL(tcp_enter_memory_pressure);
 313
 314 /*
 315  *      Wait for a TCP event.
 316  *
 317  *      Note that we don't need to lock the socket, as the upper poll layers
 318  *      take care of normal races (between the test and the event) and we don't
 319  *      go look at any of the socket buffers directly.
 320  */
 321 unsigned int tcp_poll(struct file *file, struct socket *sock, poll_table *wait)
 322 {
 323         unsigned int mask;
 324         struct sock *sk = sock->sk;
 325         struct tcp_sock *tp = tcp_sk(sk);
 326
 327         poll_wait(file, sk->sk_sleep, wait);
 328         if (sk->sk_state == TCP_LISTEN)
 329                 return inet_csk_listen_poll(sk);
 330
 331         /* Socket is not locked. We are protected from async events
 332            by poll logic and correct handling of state changes
 333            made by another threads is impossible in any case.
 334          */
 335
 336         mask = 0;
 337         if (sk->sk_err)
 338                 mask = POLLERR;
 339
 340         /*
 341          * POLLHUP is certainly not done right. But poll() doesn't
 342          * have a notion of HUP in just one direction, and for a
 343          * socket the read side is more interesting.
 344          *
 345          * Some poll() documentation says that POLLHUP is incompatible
 346          * with the POLLOUT/POLLWR flags, so somebody should check this
 347          * all. But careful, it tends to be safer to return too many
 348          * bits than too few, and you can easily break real applications
 349          * if you don't tell them that something has hung up!
 350          *
 351          * Check-me.
 352          *
 353          * Check number 1. POLLHUP is _UNMASKABLE_ event (see UNIX98 and
 354          * our fs/select.c). It means that after we received EOF,
 355          * poll always returns immediately, making impossible poll() on write()
 356          * in state CLOSE_WAIT. One solution is evident --- to set POLLHUP
 357          * if and only if shutdown has been made in both directions.
 358          * Actually, it is interesting to look how Solaris and DUX
 359          * solve this dilemma. I would prefer, if PULLHUP were maskable,
 360          * then we could set it on SND_SHUTDOWN. BTW examples given
 361          * in Stevens' books assume exactly this behaviour, it explains
 362          * why PULLHUP is incompatible with POLLOUT.    --ANK
 363          *
 364          * NOTE. Check for TCP_CLOSE is added. The goal is to prevent
 365          * blocking on fresh not-connected or disconnected socket. --ANK
 366          */
 367         if (sk->sk_shutdown == SHUTDOWN_MASK || sk->sk_state == TCP_CLOSE)
 368                 mask |= POLLHUP;
 369         if (sk->sk_shutdown & RCV_SHUTDOWN)
 370                 mask |= POLLIN | POLLRDNORM | POLLRDHUP;
 371
 372         /* Connected? */
 373         if ((1 << sk->sk_state) & ~(TCPF_SYN_SENT | TCPF_SYN_RECV)) {
 374                 /* Potential race condition. If read of tp below will
 375                  * escape above sk->sk_state, we can be illegally awaken
 376                  * in SYN_* states. */
 377                 if ((tp->rcv_nxt != tp->copied_seq) &&
 378                     (tp->urg_seq != tp->copied_seq ||
 379                      tp->rcv_nxt != tp->copied_seq + 1 ||
 380                      sock_flag(sk, SOCK_URGINLINE) || !tp->urg_data))
 381                         mask |= POLLIN | POLLRDNORM;
 382
 383                 if (!(sk->sk_shutdown & SEND_SHUTDOWN)) {
 384                         if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk)) {
 385                                 mask |= POLLOUT | POLLWRNORM;
 386                         } else {  /* send SIGIO later */
 387                                 set_bit(SOCK_ASYNC_NOSPACE,
 388                                         &sk->sk_socket->flags);
 389                                 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
 390
 391                                 /* Race breaker. If space is freed after
 392                                  * wspace test but before the flags are set,
 393                                  * IO signal will be lost.
 394                                  */
 395                                 if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk))
 396                                         mask |= POLLOUT | POLLWRNORM;
 397                         }
 398                 }
 399
 400                 if (tp->urg_data & TCP_URG_VALID)
 401                         mask |= POLLPRI;
 402         }
 403         return mask;
 404 }
 405
 406 int tcp_ioctl(struct sock *sk, int cmd, unsigned long arg)
 407 {
 408         struct tcp_sock *tp = tcp_sk(sk);
 409         int answ;
 410
 411         switch (cmd) {
 412         case SIOCINQ:
 413                 if (sk->sk_state == TCP_LISTEN)
 414                         return -EINVAL;
 415
 416                 lock_sock(sk);
 417                 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
 418                         answ = 0;
 419                 else if (sock_flag(sk, SOCK_URGINLINE) ||
 420                          !tp->urg_data ||
 421                          before(tp->urg_seq, tp->copied_seq) ||
 422                          !before(tp->urg_seq, tp->rcv_nxt)) {
 423                         answ = tp->rcv_nxt - tp->copied_seq;
 424
 425                         /* Subtract 1, if FIN is in queue. */
 426                         if (answ && !skb_queue_empty(&sk->sk_receive_queue))
 427                                 answ -=
 428                        tcp_hdr((struct sk_buff *)sk->sk_receive_queue.prev)->fin;
 429                 } else
 430                         answ = tp->urg_seq - tp->copied_seq;
 431                 release_sock(sk);
 432                 break;
 433         case SIOCATMARK:
 434                 answ = tp->urg_data && tp->urg_seq == tp->copied_seq;
 435                 break;
 436         case SIOCOUTQ:
 437                 if (sk->sk_state == TCP_LISTEN)
 438                         return -EINVAL;
 439
 440                 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
 441                         answ = 0;
 442                 else
 443                         answ = tp->write_seq - tp->snd_una;
 444                 break;
 445         default:
 446                 return -ENOIOCTLCMD;
 447         }
 448
 449         return put_user(answ, (int __user *)arg);
 450 }
 451
 452 static inline void tcp_mark_push(struct tcp_sock *tp, struct sk_buff *skb)
 453 {
 454         TCP_SKB_CB(skb)->flags |= TCPCB_FLAG_PSH;
 455         tp->pushed_seq = tp->write_seq;
 456 }
 457
 458 static inline int forced_push(struct tcp_sock *tp)
 459 {
 460         return after(tp->write_seq, tp->pushed_seq + (tp->max_window >> 1));
 461 }
 462
 463 static inline void skb_entail(struct sock *sk, struct sk_buff *skb)
 464 {
 465         struct tcp_sock *tp = tcp_sk(sk);
 466         struct tcp_skb_cb *tcb = TCP_SKB_CB(skb);
 467
 468         skb->csum    = 0;
 469         tcb->seq     = tcb->end_seq = tp->write_seq;
 470         tcb->flags   = TCPCB_FLAG_ACK;
 471         tcb->sacked  = 0;
 472         skb_header_release(skb);
 473         tcp_add_write_queue_tail(sk, skb);
 474         sk_charge_skb(sk, skb);
 475         if (tp->nonagle & TCP_NAGLE_PUSH)
 476                 tp->nonagle &= ~TCP_NAGLE_PUSH;
 477 }
 478
 479 static inline void tcp_mark_urg(struct tcp_sock *tp, int flags,
 480                                 struct sk_buff *skb)
 481 {
 482         if (flags & MSG_OOB) {
 483                 tp->urg_mode = 1;
 484                 tp->snd_up = tp->write_seq;
 485                 TCP_SKB_CB(skb)->sacked |= TCPCB_URG;
 486         }
 487 }
 488
 489 static inline void tcp_push(struct sock *sk, int flags, int mss_now,
 490                             int nonagle)
 491 {
 492         struct tcp_sock *tp = tcp_sk(sk);
 493
 494         if (tcp_send_head(sk)) {
 495                 struct sk_buff *skb = tcp_write_queue_tail(sk);
 496                 if (!(flags & MSG_MORE) || forced_push(tp))
 497                         tcp_mark_push(tp, skb);
 498                 tcp_mark_urg(tp, flags, skb);
 499                 __tcp_push_pending_frames(sk, mss_now,
 500                                           (flags & MSG_MORE) ? TCP_NAGLE_CORK : nonagle);
 501         }
 502 }
 503
 504 static ssize_t do_tcp_sendpages(struct sock *sk, struct page **pages, int poffset,
 505                          size_t psize, int flags)
 506 {
 507         struct tcp_sock *tp = tcp_sk(sk);
 508         int mss_now, size_goal;
 509         int err;
 510         ssize_t copied;
 511         long timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
 512
 513         /* Wait for a connection to finish. */
 514         if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT))
 515                 if ((err = sk_stream_wait_connect(sk, &timeo)) != 0)
 516                         goto out_err;
 517
 518         clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
 519
 520         mss_now = tcp_current_mss(sk, !(flags&MSG_OOB));
 521         size_goal = tp->xmit_size_goal;
 522         copied = 0;
 523
 524         err = -EPIPE;
 525         if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
 526                 goto do_error;
 527
 528         while (psize > 0) {
 529                 struct sk_buff *skb = tcp_write_queue_tail(sk);
 530                 struct page *page = pages[poffset / PAGE_SIZE];
 531                 int copy, i, can_coalesce;
 532                 int offset = poffset % PAGE_SIZE;
 533                 int size = min_t(size_t, psize, PAGE_SIZE - offset);
 534
 535                 if (!tcp_send_head(sk) || (copy = size_goal - skb->len) <= 0) {
 536 new_segment:
 537                         if (!sk_stream_memory_free(sk))
 538                                 goto wait_for_sndbuf;
 539
 540                         skb = sk_stream_alloc_pskb(sk, 0, 0,
 541                                                    sk->sk_allocation);
 542                         if (!skb)
 543                                 goto wait_for_memory;
 544
 545                         skb_entail(sk, skb);
 546                         copy = size_goal;
 547                 }
 548
 549                 if (copy > size)
 550                         copy = size;
 551
 552                 i = skb_shinfo(skb)->nr_frags;
 553                 can_coalesce = skb_can_coalesce(skb, i, page, offset);
 554                 if (!can_coalesce && i >= MAX_SKB_FRAGS) {
 555                         tcp_mark_push(tp, skb);
 556                         goto new_segment;
 557                 }
 558                 if (!sk_stream_wmem_schedule(sk, copy))
 559                         goto wait_for_memory;
 560
 561                 if (can_coalesce) {
 562                         skb_shinfo(skb)->frags[i - 1].size += copy;
 563                 } else {
 564                         get_page(page);
 565                         skb_fill_page_desc(skb, i, page, offset, copy);
 566                 }
 567
 568                 skb->len += copy;
 569                 skb->data_len += copy;
 570                 skb->truesize += copy;
 571                 sk->sk_wmem_queued += copy;
 572                 sk->sk_forward_alloc -= copy;
 573                 skb->ip_summed = CHECKSUM_PARTIAL;
 574                 tp->write_seq += copy;
 575                 TCP_SKB_CB(skb)->end_seq += copy;
 576                 skb_shinfo(skb)->gso_segs = 0;
 577
 578                 if (!copied)
 579                         TCP_SKB_CB(skb)->flags &= ~TCPCB_FLAG_PSH;
 580
 581                 copied += copy;
 582                 poffset += copy;
 583                 if (!(psize -= copy))
 584                         goto out;
 585
 586                 if (skb->len < mss_now || (flags & MSG_OOB))
 587                         continue;
 588
 589                 if (forced_push(tp)) {
 590                         tcp_mark_push(tp, skb);
 591                         __tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH);
 592                 } else if (skb == tcp_send_head(sk))
 593                         tcp_push_one(sk, mss_now);
 594                 continue;
 595
 596 wait_for_sndbuf:
 597                 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
 598 wait_for_memory:
 599                 if (copied)
 600                         tcp_push(sk, flags & ~MSG_MORE, mss_now, TCP_NAGLE_PUSH);
 601
 602                 if ((err = sk_stream_wait_memory(sk, &timeo)) != 0)
 603                         goto do_error;
 604
 605                 mss_now = tcp_current_mss(sk, !(flags&MSG_OOB));
 606                 size_goal = tp->xmit_size_goal;
 607         }
 608
 609 out:
 610         if (copied)
 611                 tcp_push(sk, flags, mss_now, tp->nonagle);
 612         return copied;
 613
 614 do_error:
 615         if (copied)
 616                 goto out;
 617 out_err:
 618         return sk_stream_error(sk, flags, err);
 619 }
 620
 621 ssize_t tcp_sendpage(struct socket *sock, struct page *page, int offset,
 622                      size_t size, int flags)
 623 {
 624         ssize_t res;
 625         struct sock *sk = sock->sk;
 626
 627         if (!(sk->sk_route_caps & NETIF_F_SG) ||
 628             !(sk->sk_route_caps & NETIF_F_ALL_CSUM))
 629                 return sock_no_sendpage(sock, page, offset, size, flags);
 630
 631         lock_sock(sk);
 632         TCP_CHECK_TIMER(sk);
 633         res = do_tcp_sendpages(sk, &page, offset, size, flags);
 634         TCP_CHECK_TIMER(sk);
 635         release_sock(sk);
 636         return res;
 637 }
 638
 639 #define TCP_PAGE(sk)    (sk->sk_sndmsg_page)
 640 #define TCP_OFF(sk)     (sk->sk_sndmsg_off)
 641
 642 static inline int select_size(struct sock *sk)
 643 {
 644         struct tcp_sock *tp = tcp_sk(sk);
 645         int tmp = tp->mss_cache;
 646
 647         if (sk->sk_route_caps & NETIF_F_SG) {
 648                 if (sk_can_gso(sk))
 649                         tmp = 0;
 650                 else {
 651                         int pgbreak = SKB_MAX_HEAD(MAX_TCP_HEADER);
 652
 653                         if (tmp >= pgbreak &&
 654                             tmp <= pgbreak + (MAX_SKB_FRAGS - 1) * PAGE_SIZE)
 655                                 tmp = pgbreak;
 656                 }
 657         }
 658
 659         return tmp;
 660 }
 661
 662 int tcp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
 663                 size_t size)
 664 {
 665         struct iovec *iov;
 666         struct tcp_sock *tp = tcp_sk(sk);
 667         struct sk_buff *skb;
 668         int iovlen, flags;
 669         int mss_now, size_goal;
 670         int err, copied;
 671         long timeo;
 672
 673         lock_sock(sk);
 674         TCP_CHECK_TIMER(sk);
 675
 676         flags = msg->msg_flags;
 677         timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
 678
 679         /* Wait for a connection to finish. */
 680         if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT))
 681                 if ((err = sk_stream_wait_connect(sk, &timeo)) != 0)
 682                         goto out_err;
 683
 684         /* This should be in poll */
 685         clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
 686
 687         mss_now = tcp_current_mss(sk, !(flags&MSG_OOB));
 688         size_goal = tp->xmit_size_goal;
 689
 690         /* Ok commence sending. */
 691         iovlen = msg->msg_iovlen;
 692         iov = msg->msg_iov;
 693         copied = 0;
 694
 695         err = -EPIPE;
 696         if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
 697                 goto do_error;
 698
 699         while (--iovlen >= 0) {
 700                 int seglen = iov->iov_len;
 701                 unsigned char __user *from = iov->iov_base;
 702
 703                 iov++;
 704
 705                 while (seglen > 0) {
 706                         int copy;
 707
 708                         skb = tcp_write_queue_tail(sk);
 709
 710                         if (!tcp_send_head(sk) ||
 711                             (copy = size_goal - skb->len) <= 0) {
 712
 713 new_segment:
 714                                 /* Allocate new segment. If the interface is SG,
 715                                  * allocate skb fitting to single page.
 716                                  */
 717                                 if (!sk_stream_memory_free(sk))
 718                                         goto wait_for_sndbuf;
 719
 720                                 skb = sk_stream_alloc_pskb(sk, select_size(sk),
 721                                                            0, sk->sk_allocation);
 722                                 if (!skb)
 723                                         goto wait_for_memory;
 724
 725                                 /*
 726                                  * Check whether we can use HW checksum.
 727                                  */
 728                                 if (sk->sk_route_caps & NETIF_F_ALL_CSUM)
 729                                         skb->ip_summed = CHECKSUM_PARTIAL;
 730
 731                                 skb_entail(sk, skb);
 732                                 copy = size_goal;
 733                         }
 734
 735                         /* Try to append data to the end of skb. */
 736                         if (copy > seglen)
 737                                 copy = seglen;
 738
 739                         /* Where to copy to? */
 740                         if (skb_tailroom(skb) > 0) {
 741                                 /* We have some space in skb head. Superb! */
 742                                 if (copy > skb_tailroom(skb))
 743                                         copy = skb_tailroom(skb);
 744                                 if ((err = skb_add_data(skb, from, copy)) != 0)
 745                                         goto do_fault;
 746                         } else {
 747                                 int merge = 0;
 748                                 int i = skb_shinfo(skb)->nr_frags;
 749                                 struct page *page = TCP_PAGE(sk);
 750                                 int off = TCP_OFF(sk);
 751
 752                                 if (skb_can_coalesce(skb, i, page, off) &&
 753                                     off != PAGE_SIZE) {
 754                                         /* We can extend the last page
 755                                          * fragment. */
 756                                         merge = 1;
 757                                 } else if (i == MAX_SKB_FRAGS ||
 758                                            (!i &&
 759                                            !(sk->sk_route_caps & NETIF_F_SG))) {
 760                                         /* Need to add new fragment and cannot
 761                                          * do this because interface is non-SG,
 762                                          * or because all the page slots are
 763                                          * busy. */
 764                                         tcp_mark_push(tp, skb);
 765                                         goto new_segment;
 766                                 } else if (page) {
 767                                         if (off == PAGE_SIZE) {
 768                                                 put_page(page);
 769                                                 TCP_PAGE(sk) = page = NULL;
 770                                                 off = 0;
 771                                         }
 772                                 } else
 773                                         off = 0;
 774
 775                                 if (copy > PAGE_SIZE - off)
 776                                         copy = PAGE_SIZE - off;
 777
 778                                 if (!sk_stream_wmem_schedule(sk, copy))
 779                                         goto wait_for_memory;
 780
 781                                 if (!page) {
 782                                         /* Allocate new cache page. */
 783                                         if (!(page = sk_stream_alloc_page(sk)))
 784                                                 goto wait_for_memory;
 785                                 }
 786
 787                                 /* Time to copy data. We are close to
 788                                  * the end! */
 789                                 err = skb_copy_to_page(sk, from, skb, page,
 790                                                        off, copy);
 791                                 if (err) {
 792                                         /* If this page was new, give it to the
 793                                          * socket so it does not get leaked.
 794                                          */
 795                                         if (!TCP_PAGE(sk)) {
 796                                                 TCP_PAGE(sk) = page;
 797                                                 TCP_OFF(sk) = 0;
 798                                         }
 799                                         goto do_error;
 800                                 }
 801
 802                                 /* Update the skb. */
 803                                 if (merge) {
 804                                         skb_shinfo(skb)->frags[i - 1].size +=
 805                                                                         copy;
 806                                 } else {
 807                                         skb_fill_page_desc(skb, i, page, off, copy);
 808                                         if (TCP_PAGE(sk)) {
 809                                                 get_page(page);
 810                                         } else if (off + copy < PAGE_SIZE) {
 811                                                 get_page(page);
 812                                                 TCP_PAGE(sk) = page;
 813                                         }
 814                                 }
 815
 816                                 TCP_OFF(sk) = off + copy;
 817                         }
 818
 819                         if (!copied)
 820                                 TCP_SKB_CB(skb)->flags &= ~TCPCB_FLAG_PSH;
 821
 822                         tp->write_seq += copy;
 823                         TCP_SKB_CB(skb)->end_seq += copy;
 824                         skb_shinfo(skb)->gso_segs = 0;
 825
 826                         from += copy;
 827                         copied += copy;
 828                         if ((seglen -= copy) == 0 && iovlen == 0)
 829                                 goto out;
 830
 831                         if (skb->len < mss_now || (flags & MSG_OOB))
 832                                 continue;
 833
 834                         if (forced_push(tp)) {
 835                                 tcp_mark_push(tp, skb);
 836                                 __tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH);
 837                         } else if (skb == tcp_send_head(sk))
 838                                 tcp_push_one(sk, mss_now);
 839                         continue;
 840
 841 wait_for_sndbuf:
 842                         set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
 843 wait_for_memory:
 844                         if (copied)
 845                                 tcp_push(sk, flags & ~MSG_MORE, mss_now, TCP_NAGLE_PUSH);
 846
 847                         if ((err = sk_stream_wait_memory(sk, &timeo)) != 0)
 848                                 goto do_error;
 849
 850                         mss_now = tcp_current_mss(sk, !(flags&MSG_OOB));
 851                         size_goal = tp->xmit_size_goal;
 852                 }
 853         }
 854
 855 out:
 856         if (copied)
 857                 tcp_push(sk, flags, mss_now, tp->nonagle);
 858         TCP_CHECK_TIMER(sk);
 859         release_sock(sk);
 860         return copied;
 861
 862 do_fault:
 863         if (!skb->len) {
 864                 tcp_unlink_write_queue(skb, sk);
 865                 /* It is the one place in all of TCP, except connection
 866                  * reset, where we can be unlinking the send_head.
 867                  */
 868                 tcp_check_send_head(sk, skb);
 869                 sk_stream_free_skb(sk, skb);
 870         }
 871
 872 do_error:
 873         if (copied)
 874                 goto out;
 875 out_err:
 876         err = sk_stream_error(sk, flags, err);
 877         TCP_CHECK_TIMER(sk);
 878         release_sock(sk);
 879         return err;
 880 }
 881
 882 /*
 883  *      Handle reading urgent data. BSD has very simple semantics for
 884  *      this, no blocking and very strange errors 8)
 885  */
 886
 887 static int tcp_recv_urg(struct sock *sk, long timeo,
 888                         struct msghdr *msg, int len, int flags,
 889                         int *addr_len)
 890 {
 891         struct tcp_sock *tp = tcp_sk(sk);
 892
 893         /* No URG data to read. */
 894         if (sock_flag(sk, SOCK_URGINLINE) || !tp->urg_data ||
 895             tp->urg_data == TCP_URG_READ)
 896                 return -EINVAL; /* Yes this is right ! */
 897
 898         if (sk->sk_state == TCP_CLOSE && !sock_flag(sk, SOCK_DONE))
 899                 return -ENOTCONN;
 900
 901         if (tp->urg_data & TCP_URG_VALID) {
 902                 int err = 0;
 903                 char c = tp->urg_data;
 904
 905                 if (!(flags & MSG_PEEK))
 906                         tp->urg_data = TCP_URG_READ;
 907
 908                 /* Read urgent data. */
 909                 msg->msg_flags |= MSG_OOB;
 910
 911                 if (len > 0) {
 912                         if (!(flags & MSG_TRUNC))
 913                                 err = memcpy_toiovec(msg->msg_iov, &c, 1);
 914                         len = 1;
 915                 } else
 916                         msg->msg_flags |= MSG_TRUNC;
 917
 918                 return err ? -EFAULT : len;
 919         }
 920
 921         if (sk->sk_state == TCP_CLOSE || (sk->sk_shutdown & RCV_SHUTDOWN))
 922                 return 0;
 923
 924         /* Fixed the recv(..., MSG_OOB) behaviour.  BSD docs and
 925          * the available implementations agree in this case:
 926          * this call should never block, independent of the
 927          * blocking state of the socket.
 928          * Mike <pall@rz.uni-karlsruhe.de>
 929          */
 930         return -EAGAIN;
 931 }
 932
 933 /* Clean up the receive buffer for full frames taken by the user,
 934  * then send an ACK if necessary.  COPIED is the number of bytes
 935  * tcp_recvmsg has given to the user so far, it speeds up the
 936  * calculation of whether or not we must ACK for the sake of
 937  * a window update.
 938  */
 939 void tcp_cleanup_rbuf(struct sock *sk, int copied)
 940 {
 941         struct tcp_sock *tp = tcp_sk(sk);
 942         int time_to_ack = 0;
 943
 944 #if TCP_DEBUG
 945         struct sk_buff *skb = skb_peek(&sk->sk_receive_queue);
 946
 947         BUG_TRAP(!skb || before(tp->copied_seq, TCP_SKB_CB(skb)->end_seq));
 948 #endif
 949
 950         if (inet_csk_ack_scheduled(sk)) {
 951                 const struct inet_connection_sock *icsk = inet_csk(sk);
 952                    /* Delayed ACKs frequently hit locked sockets during bulk
 953                     * receive. */
 954                 if (icsk->icsk_ack.blocked ||
 955                     /* Once-per-two-segments ACK was not sent by tcp_input.c */
 956                     tp->rcv_nxt - tp->rcv_wup > icsk->icsk_ack.rcv_mss ||
 957                     /*
 958                      * If this read emptied read buffer, we send ACK, if
 959                      * connection is not bidirectional, user drained
 960                      * receive buffer and there was a small segment
 961                      * in queue.
 962                      */
 963                     (copied > 0 &&
 964                      ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED2) ||
 965                       ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED) &&
 966                        !icsk->icsk_ack.pingpong)) &&
 967                       !atomic_read(&sk->sk_rmem_alloc)))
 968                         time_to_ack = 1;
 969         }
 970
 971         /* We send an ACK if we can now advertise a non-zero window
 972          * which has been raised "significantly".
 973          *
 974          * Even if window raised up to infinity, do not send window open ACK
 975          * in states, where we will not receive more. It is useless.
 976          */
 977         if (copied > 0 && !time_to_ack && !(sk->sk_shutdown & RCV_SHUTDOWN)) {
 978                 __u32 rcv_window_now = tcp_receive_window(tp);
 979
 980                 /* Optimize, __tcp_select_window() is not cheap. */
 981                 if (2*rcv_window_now <= tp->window_clamp) {
 982                         __u32 new_window = __tcp_select_window(sk);
 983
 984                         /* Send ACK now, if this read freed lots of space
 985                          * in our buffer. Certainly, new_window is new window.
 986                          * We can advertise it now, if it is not less than current one.
 987                          * "Lots" means "at least twice" here.
 988                          */
 989                         if (new_window && new_window >= 2 * rcv_window_now)
 990                                 time_to_ack = 1;
 991                 }
 992         }
 993         if (time_to_ack)
 994                 tcp_send_ack(sk);
 995 }
 996
 997 static void tcp_prequeue_process(struct sock *sk)
 998 {
 999         struct sk_buff *skb;
1000         struct tcp_sock *tp = tcp_sk(sk);
1001
1002         NET_INC_STATS_USER(LINUX_MIB_TCPPREQUEUED);
1003
1004         /* RX process wants to run with disabled BHs, though it is not
1005          * necessary */
1006         local_bh_disable();
1007         while ((skb = __skb_dequeue(&tp->ucopy.prequeue)) != NULL)
1008                 sk->sk_backlog_rcv(sk, skb);
1009         local_bh_enable();
1010
1011         /* Clear memory counter. */
1012         tp->ucopy.memory = 0;
1013 }
1014
1015 static inline struct sk_buff *tcp_recv_skb(struct sock *sk, u32 seq, u32 *off)
1016 {
1017         struct sk_buff *skb;
1018         u32 offset;
1019
1020         skb_queue_walk(&sk->sk_receive_queue, skb) {
1021                 offset = seq - TCP_SKB_CB(skb)->seq;
1022                 if (tcp_hdr(skb)->syn)
1023                         offset--;
1024                 if (offset < skb->len || tcp_hdr(skb)->fin) {
1025                         *off = offset;
1026                         return skb;
1027                 }
1028         }
1029         return NULL;
1030 }
1031
1032 /*
1033  * This routine provides an alternative to tcp_recvmsg() for routines
1034  * that would like to handle copying from skbuffs directly in 'sendfile'
1035  * fashion.
1036  * Note:
1037  *      - It is assumed that the socket was locked by the caller.
1038  *      - The routine does not block.
1039  *      - At present, there is no support for reading OOB data
1040  *        or for 'peeking' the socket using this routine
1041  *        (although both would be easy to implement).
1042  */
1043 int tcp_read_sock(struct sock *sk, read_descriptor_t *desc,
1044                   sk_read_actor_t recv_actor)
1045 {
1046         struct sk_buff *skb;
1047         struct tcp_sock *tp = tcp_sk(sk);
1048         u32 seq = tp->copied_seq;
1049         u32 offset;
1050         int copied = 0;
1051
1052         if (sk->sk_state == TCP_LISTEN)
1053                 return -ENOTCONN;
1054         while ((skb = tcp_recv_skb(sk, seq, &offset)) != NULL) {
1055                 if (offset < skb->len) {
1056                         size_t used, len;
1057
1058                         len = skb->len - offset;
1059                         /* Stop reading if we hit a patch of urgent data */
1060                         if (tp->urg_data) {
1061                                 u32 urg_offset = tp->urg_seq - seq;
1062                                 if (urg_offset < len)
1063                                         len = urg_offset;
1064                                 if (!len)
1065                                         break;
1066                         }
1067                         used = recv_actor(desc, skb, offset, len);
1068                         if (used <= len) {
1069                                 seq += used;
1070                                 copied += used;
1071                                 offset += used;
1072                         }
1073                         if (offset != skb->len)
1074                                 break;
1075                 }
1076                 if (tcp_hdr(skb)->fin) {
1077                         sk_eat_skb(sk, skb, 0);
1078                         ++seq;
1079                         break;
1080                 }
1081                 sk_eat_skb(sk, skb, 0);
1082                 if (!desc->count)
1083                         break;
1084         }
1085         tp->copied_seq = seq;
1086
1087         tcp_rcv_space_adjust(sk);
1088
1089         /* Clean up data we have read: This will do ACK frames. */
1090         if (copied)
1091                 tcp_cleanup_rbuf(sk, copied);
1092         return copied;
1093 }
1094
1095 /*
1096  *      This routine copies from a sock struct into the user buffer.
1097  *
1098  *      Technical note: in 2.3 we work on _locked_ socket, so that
1099  *      tricks with *seq access order and skb->users are not required.
1100  *      Probably, code can be easily improved even more.
1101  */
1102
1103 int tcp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
1104                 size_t len, int nonblock, int flags, int *addr_len)
1105 {
1106         struct tcp_sock *tp = tcp_sk(sk);
1107         int copied = 0;
1108         u32 peek_seq;
1109         u32 *seq;
1110         unsigned long used;
1111         int err;
1112         int target;             /* Read at least this many bytes */
1113         long timeo;
1114         struct task_struct *user_recv = NULL;
1115         int copied_early = 0;
1116
1117         lock_sock(sk);
1118
1119         TCP_CHECK_TIMER(sk);
1120
1121         err = -ENOTCONN;
1122         if (sk->sk_state == TCP_LISTEN)
1123                 goto out;
1124
1125         timeo = sock_rcvtimeo(sk, nonblock);
1126
1127         /* Urgent data needs to be handled specially. */
1128         if (flags & MSG_OOB)
1129                 goto recv_urg;
1130
1131         seq = &tp->copied_seq;
1132         if (flags & MSG_PEEK) {
1133                 peek_seq = tp->copied_seq;
1134                 seq = &peek_seq;
1135         }
1136
1137         target = sock_rcvlowat(sk, flags & MSG_WAITALL, len);
1138
1139 #ifdef CONFIG_NET_DMA
1140         tp->ucopy.dma_chan = NULL;
1141         preempt_disable();
1142         if ((len > sysctl_tcp_dma_copybreak) && !(flags & MSG_PEEK) &&
1143             !sysctl_tcp_low_latency && __get_cpu_var(softnet_data).net_dma) {
1144                 preempt_enable_no_resched();
1145                 tp->ucopy.pinned_list = dma_pin_iovec_pages(msg->msg_iov, len);
1146         } else
1147                 preempt_enable_no_resched();
1148 #endif
1149
1150         do {
1151                 struct sk_buff *skb;
1152                 u32 offset;
1153
1154                 /* Are we at urgent data? Stop if we have read anything or have SIGURG pending. */
1155                 if (tp->urg_data && tp->urg_seq == *seq) {
1156                         if (copied)
1157                                 break;
1158                         if (signal_pending(current)) {
1159                                 copied = timeo ? sock_intr_errno(timeo) : -EAGAIN;
1160                                 break;
1161                         }
1162                 }
1163
1164                 /* Next get a buffer. */
1165
1166                 skb = skb_peek(&sk->sk_receive_queue);
1167                 do {
1168                         if (!skb)
1169                                 break;
1170
1171                         /* Now that we have two receive queues this
1172                          * shouldn't happen.
1173                          */
1174                         if (before(*seq, TCP_SKB_CB(skb)->seq)) {
1175                                 printk(KERN_INFO "recvmsg bug: copied %X "
1176                                        "seq %X\n", *seq, TCP_SKB_CB(skb)->seq);
1177                                 break;
1178                         }
1179                         offset = *seq - TCP_SKB_CB(skb)->seq;
1180                         if (tcp_hdr(skb)->syn)
1181                                 offset--;
1182                         if (offset < skb->len)
1183                                 goto found_ok_skb;
1184                         if (tcp_hdr(skb)->fin)
1185                                 goto found_fin_ok;
1186                         BUG_TRAP(flags & MSG_PEEK);
1187                         skb = skb->next;
1188                 } while (skb != (struct sk_buff *)&sk->sk_receive_queue);
1189
1190                 /* Well, if we have backlog, try to process it now yet. */
1191
1192                 if (copied >= target && !sk->sk_backlog.tail)
1193                         break;
1194
1195                 if (copied) {
1196                         if (sk->sk_err ||
1197                             sk->sk_state == TCP_CLOSE ||
1198                             (sk->sk_shutdown & RCV_SHUTDOWN) ||
1199                             !timeo ||
1200                             signal_pending(current) ||
1201                             (flags & MSG_PEEK))
1202                                 break;
1203                 } else {
1204                         if (sock_flag(sk, SOCK_DONE))
1205                                 break;
1206
1207                         if (sk->sk_err) {
1208                                 copied = sock_error(sk);
1209                                 break;
1210                         }
1211
1212                         if (sk->sk_shutdown & RCV_SHUTDOWN)
1213                                 break;
1214
1215                         if (sk->sk_state == TCP_CLOSE) {
1216                                 if (!sock_flag(sk, SOCK_DONE)) {
1217                                         /* This occurs when user tries to read
1218                                          * from never connected socket.
1219                                          */
1220                                         copied = -ENOTCONN;
1221                                         break;
1222                                 }
1223                                 break;
1224                         }
1225
1226                         if (!timeo) {
1227                                 copied = -EAGAIN;
1228                                 break;
1229                         }
1230
1231                         if (signal_pending(current)) {
1232                                 copied = sock_intr_errno(timeo);
1233                                 break;
1234                         }
1235                 }
1236
1237                 tcp_cleanup_rbuf(sk, copied);
1238
1239                 if (!sysctl_tcp_low_latency && tp->ucopy.task == user_recv) {
1240                         /* Install new reader */
1241                         if (!user_recv && !(flags & (MSG_TRUNC | MSG_PEEK))) {
1242                                 user_recv = current;
1243                                 tp->ucopy.task = user_recv;
1244                                 tp->ucopy.iov = msg->msg_iov;
1245                         }
1246
1247                         tp->ucopy.len = len;
1248
1249                         BUG_TRAP(tp->copied_seq == tp->rcv_nxt ||
1250                                  (flags & (MSG_PEEK | MSG_TRUNC)));
1251
1252                         /* Ugly... If prequeue is not empty, we have to
1253                          * process it before releasing socket, otherwise
1254                          * order will be broken at second iteration.
1255                          * More elegant solution is required!!!
1256                          *
1257                          * Look: we have the following (pseudo)queues:
1258                          *
1259                          * 1. packets in flight
1260                          * 2. backlog
1261                          * 3. prequeue
1262                          * 4. receive_queue
1263                          *
1264                          * Each queue can be processed only if the next ones
1265                          * are empty. At this point we have empty receive_queue.
1266                          * But prequeue _can_ be not empty after 2nd iteration,
1267                          * when we jumped to start of loop because backlog
1268                          * processing added something to receive_queue.
1269                          * We cannot release_sock(), because backlog contains
1270                          * packets arrived _after_ prequeued ones.
1271                          *
1272                          * Shortly, algorithm is clear --- to process all
1273                          * the queues in order. We could make it more directly,
1274                          * requeueing packets from backlog to prequeue, if
1275                          * is not empty. It is more elegant, but eats cycles,
1276                          * unfortunately.
1277                          */
1278                         if (!skb_queue_empty(&tp->ucopy.prequeue))
1279                                 goto do_prequeue;
1280
1281                         /* __ Set realtime policy in scheduler __ */
1282                 }
1283
1284                 if (copied >= target) {
1285                         /* Do not sleep, just process backlog. */
1286                         release_sock(sk);
1287                         lock_sock(sk);
1288                 } else
1289                         sk_wait_data(sk, &timeo);
1290
1291 #ifdef CONFIG_NET_DMA
1292                 tp->ucopy.wakeup = 0;
1293 #endif
1294
1295                 if (user_recv) {
1296                         int chunk;
1297
1298                         /* __ Restore normal policy in scheduler __ */
1299
1300                         if ((chunk = len - tp->ucopy.len) != 0) {
1301                                 NET_ADD_STATS_USER(LINUX_MIB_TCPDIRECTCOPYFROMBACKLOG, chunk);
1302                                 len -= chunk;
1303                                 copied += chunk;
1304                         }
1305
1306                         if (tp->rcv_nxt == tp->copied_seq &&
1307                             !skb_queue_empty(&tp->ucopy.prequeue)) {
1308 do_prequeue:
1309                                 tcp_prequeue_process(sk);
1310
1311                                 if ((chunk = len - tp->ucopy.len) != 0) {
1312                                         NET_ADD_STATS_USER(LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
1313                                         len -= chunk;
1314                                         copied += chunk;
1315                                 }
1316                         }
1317                 }
1318                 if ((flags & MSG_PEEK) && peek_seq != tp->copied_seq) {
1319                         if (net_ratelimit())
1320                                 printk(KERN_DEBUG "TCP(%s:%d): Application bug, race in MSG_PEEK.\n",
1321                                        current->comm, current->pid);
1322                         peek_seq = tp->copied_seq;
1323                 }
1324                 continue;
1325
1326         found_ok_skb:
1327                 /* Ok so how much can we use? */
1328                 used = skb->len - offset;
1329                 if (len < used)
1330                         used = len;
1331
1332                 /* Do we have urgent data here? */
1333                 if (tp->urg_data) {
1334                         u32 urg_offset = tp->urg_seq - *seq;
1335                         if (urg_offset < used) {
1336                                 if (!urg_offset) {
1337                                         if (!sock_flag(sk, SOCK_URGINLINE)) {
1338                                                 ++*seq;
1339                                                 offset++;
1340                                                 used--;
1341                                                 if (!used)
1342                                                         goto skip_copy;
1343                                         }
1344                                 } else
1345                                         used = urg_offset;
1346                         }
1347                 }
1348
1349                 if (!(flags & MSG_TRUNC)) {
1350 #ifdef CONFIG_NET_DMA
1351                         if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list)
1352                                 tp->ucopy.dma_chan = get_softnet_dma();
1353
1354                         if (tp->ucopy.dma_chan) {
1355                                 tp->ucopy.dma_cookie = dma_skb_copy_datagram_iovec(
1356                                         tp->ucopy.dma_chan, skb, offset,
1357                                         msg->msg_iov, used,
1358                                         tp->ucopy.pinned_list);
1359
1360                                 if (tp->ucopy.dma_cookie < 0) {
1361
1362                                         printk(KERN_ALERT "dma_cookie < 0\n");
1363
1364                                         /* Exception. Bailout! */
1365                                         if (!copied)
1366                                                 copied = -EFAULT;
1367                                         break;
1368                                 }
1369                                 if ((offset + used) == skb->len)
1370                                         copied_early = 1;
1371
1372                         } else
1373 #endif
1374                         {
1375                                 err = skb_copy_datagram_iovec(skb, offset,
1376                                                 msg->msg_iov, used);
1377                                 if (err) {
1378                                         /* Exception. Bailout! */
1379                                         if (!copied)
1380                                                 copied = -EFAULT;
1381                                         break;
1382                                 }
1383                         }
1384                 }
1385
1386                 *seq += used;
1387                 copied += used;
1388                 len -= used;
1389
1390                 tcp_rcv_space_adjust(sk);
1391
1392 skip_copy:
1393                 if (tp->urg_data && after(tp->copied_seq, tp->urg_seq)) {
1394                         tp->urg_data = 0;
1395                         tcp_fast_path_check(sk);
1396                 }
1397                 if (used + offset < skb->len)
1398                         continue;
1399
1400                 if (tcp_hdr(skb)->fin)
1401                         goto found_fin_ok;
1402                 if (!(flags & MSG_PEEK)) {
1403                         sk_eat_skb(sk, skb, copied_early);
1404                         copied_early = 0;
1405                 }
1406                 continue;
1407
1408         found_fin_ok:
1409                 /* Process the FIN. */
1410                 ++*seq;
1411                 if (!(flags & MSG_PEEK)) {
1412                         sk_eat_skb(sk, skb, copied_early);
1413                         copied_early = 0;
1414                 }
1415                 break;
1416         } while (len > 0);
1417
1418         if (user_recv) {
1419                 if (!skb_queue_empty(&tp->ucopy.prequeue)) {
1420                         int chunk;
1421
1422                         tp->ucopy.len = copied > 0 ? len : 0;
1423
1424                         tcp_prequeue_process(sk);
1425
1426                         if (copied > 0 && (chunk = len - tp->ucopy.len) != 0) {
1427                                 NET_ADD_STATS_USER(LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
1428                                 len -= chunk;
1429                                 copied += chunk;
1430                         }
1431                 }
1432
1433                 tp->ucopy.task = NULL;
1434                 tp->ucopy.len = 0;
1435         }
1436
1437 #ifdef CONFIG_NET_DMA
1438         if (tp->ucopy.dma_chan) {
1439                 struct sk_buff *skb;
1440                 dma_cookie_t done, used;
1441
1442                 dma_async_memcpy_issue_pending(tp->ucopy.dma_chan);
1443
1444                 while (dma_async_memcpy_complete(tp->ucopy.dma_chan,
1445                                                  tp->ucopy.dma_cookie, &done,
1446                                                  &used) == DMA_IN_PROGRESS) {
1447                         /* do partial cleanup of sk_async_wait_queue */
1448                         while ((skb = skb_peek(&sk->sk_async_wait_queue)) &&
1449                                (dma_async_is_complete(skb->dma_cookie, done,
1450                                                       used) == DMA_SUCCESS)) {
1451                                 __skb_dequeue(&sk->sk_async_wait_queue);
1452                                 kfree_skb(skb);
1453                         }
1454                 }
1455
1456                 /* Safe to free early-copied skbs now */
1457                 __skb_queue_purge(&sk->sk_async_wait_queue);
1458                 dma_chan_put(tp->ucopy.dma_chan);
1459                 tp->ucopy.dma_chan = NULL;
1460         }
1461         if (tp->ucopy.pinned_list) {
1462                 dma_unpin_iovec_pages(tp->ucopy.pinned_list);
1463                 tp->ucopy.pinned_list = NULL;
1464         }
1465 #endif
1466
1467         /* According to UNIX98, msg_name/msg_namelen are ignored
1468          * on connected socket. I was just happy when found this 8) --ANK
1469          */
1470
1471         /* Clean up data we have read: This will do ACK frames. */
1472         tcp_cleanup_rbuf(sk, copied);
1473
1474         TCP_CHECK_TIMER(sk);
1475         release_sock(sk);
1476         return copied;
1477
1478 out:
1479         TCP_CHECK_TIMER(sk);
1480         release_sock(sk);
1481         return err;
1482
1483 recv_urg:
1484         err = tcp_recv_urg(sk, timeo, msg, len, flags, addr_len);
1485         goto out;
1486 }
1487
1488 /*
1489  *      State processing on a close. This implements the state shift for
1490  *      sending our FIN frame. Note that we only send a FIN for some
1491  *      states. A shutdown() may have already sent the FIN, or we may be
1492  *      closed.
1493  */
1494
1495 static const unsigned char new_state[16] = {
1496   /* current state:        new state:      action:      */
1497   /* (Invalid)          */ TCP_CLOSE,
1498   /* TCP_ESTABLISHED    */ TCP_FIN_WAIT1 | TCP_ACTION_FIN,
1499   /* TCP_SYN_SENT       */ TCP_CLOSE,
1500   /* TCP_SYN_RECV       */ TCP_FIN_WAIT1 | TCP_ACTION_FIN,
1501   /* TCP_FIN_WAIT1      */ TCP_FIN_WAIT1,
1502   /* TCP_FIN_WAIT2      */ TCP_FIN_WAIT2,
1503   /* TCP_TIME_WAIT      */ TCP_CLOSE,
1504   /* TCP_CLOSE          */ TCP_CLOSE,
1505   /* TCP_CLOSE_WAIT     */ TCP_LAST_ACK  | TCP_ACTION_FIN,
1506   /* TCP_LAST_ACK       */ TCP_LAST_ACK,
1507   /* TCP_LISTEN         */ TCP_CLOSE,
1508   /* TCP_CLOSING        */ TCP_CLOSING,
1509 };
1510
1511 static int tcp_close_state(struct sock *sk)
1512 {
1513         int next = (int)new_state[sk->sk_state];
1514         int ns = next & TCP_STATE_MASK;
1515
1516         tcp_set_state(sk, ns);
1517
1518         return next & TCP_ACTION_FIN;
1519 }
1520
1521 /*
1522  *      Shutdown the sending side of a connection. Much like close except
1523  *      that we don't receive shut down or set_sock_flag(sk, SOCK_DEAD).
1524  */
1525
1526 void tcp_shutdown(struct sock *sk, int how)
1527 {
1528         /*      We need to grab some memory, and put together a FIN,
1529          *      and then put it into the queue to be sent.
1530          *              Tim MacKenzie(tym@dibbler.cs.monash.edu.au) 4 Dec '92.
1531          */
1532         if (!(how & SEND_SHUTDOWN))
1533                 return;
1534
1535         /* If we've already sent a FIN, or it's a closed state, skip this. */
1536         if ((1 << sk->sk_state) &
1537             (TCPF_ESTABLISHED | TCPF_SYN_SENT |
1538              TCPF_SYN_RECV | TCPF_CLOSE_WAIT)) {
1539                 /* Clear out any half completed packets.  FIN if needed. */
1540                 if (tcp_close_state(sk))
1541                         tcp_send_fin(sk);
1542         }
1543 }
1544
1545 void tcp_close(struct sock *sk, long timeout)
1546 {
1547         struct sk_buff *skb;
1548         int data_was_unread = 0;
1549         int state;
1550
1551         lock_sock(sk);
1552         sk->sk_shutdown = SHUTDOWN_MASK;
1553
1554         if (sk->sk_state == TCP_LISTEN) {
1555                 tcp_set_state(sk, TCP_CLOSE);
1556
1557                 /* Special case. */
1558                 inet_csk_listen_stop(sk);
1559
1560                 goto adjudge_to_death;
1561         }
1562
1563         /*  We need to flush the recv. buffs.  We do this only on the
1564          *  descriptor close, not protocol-sourced closes, because the
1565          *  reader process may not have drained the data yet!
1566          */
1567         while ((skb = __skb_dequeue(&sk->sk_receive_queue)) != NULL) {
1568                 u32 len = TCP_SKB_CB(skb)->end_seq - TCP_SKB_CB(skb)->seq -
1569                           tcp_hdr(skb)->fin;
1570                 data_was_unread += len;
1571                 __kfree_skb(skb);
1572         }
1573
1574         sk_stream_mem_reclaim(sk);
1575
1576         /* As outlined in draft-ietf-tcpimpl-prob-03.txt, section
1577          * 3.10, we send a RST here because data was lost.  To
1578          * witness the awful effects of the old behavior of always
1579          * doing a FIN, run an older 2.1.x kernel or 2.0.x, start
1580          * a bulk GET in an FTP client, suspend the process, wait
1581          * for the client to advertise a zero window, then kill -9
1582          * the FTP client, wheee...  Note: timeout is always zero
1583          * in such a case.
1584          */
1585         if (data_was_unread) {
1586                 /* Unread data was tossed, zap the connection. */
1587                 NET_INC_STATS_USER(LINUX_MIB_TCPABORTONCLOSE);
1588                 tcp_set_state(sk, TCP_CLOSE);
1589                 tcp_send_active_reset(sk, GFP_KERNEL);
1590         } else if (sock_flag(sk, SOCK_LINGER) && !sk->sk_lingertime) {
1591                 /* Check zero linger _after_ checking for unread data. */
1592                 sk->sk_prot->disconnect(sk, 0);
1593                 NET_INC_STATS_USER(LINUX_MIB_TCPABORTONDATA);
1594         } else if (tcp_close_state(sk)) {
1595                 /* We FIN if the application ate all the data before
1596                  * zapping the connection.
1597                  */
1598
1599                 /* RED-PEN. Formally speaking, we have broken TCP state
1600                  * machine. State transitions:
1601                  *
1602                  * TCP_ESTABLISHED -> TCP_FIN_WAIT1
1603                  * TCP_SYN_RECV -> TCP_FIN_WAIT1 (forget it, it's impossible)
1604                  * TCP_CLOSE_WAIT -> TCP_LAST_ACK
1605                  *
1606                  * are legal only when FIN has been sent (i.e. in window),
1607                  * rather than queued out of window. Purists blame.
1608                  *
1609                  * F.e. "RFC state" is ESTABLISHED,
1610                  * if Linux state is FIN-WAIT-1, but FIN is still not sent.
1611                  *
1612                  * The visible declinations are that sometimes
1613                  * we enter time-wait state, when it is not required really
1614                  * (harmless), do not send active resets, when they are
1615                  * required by specs (TCP_ESTABLISHED, TCP_CLOSE_WAIT, when
1616                  * they look as CLOSING or LAST_ACK for Linux)
1617                  * Probably, I missed some more holelets.
1618                  *                                              --ANK
1619                  */
1620                 tcp_send_fin(sk);
1621         }
1622
1623         sk_stream_wait_close(sk, timeout);
1624
1625 adjudge_to_death:
1626         state = sk->sk_state;
1627         sock_hold(sk);
1628         sock_orphan(sk);
1629         atomic_inc(sk->sk_prot->orphan_count);
1630
1631         /* It is the last release_sock in its life. It will remove backlog. */
1632         release_sock(sk);
1633
1634
1635         /* Now socket is owned by kernel and we acquire BH lock
1636            to finish close. No need to check for user refs.
1637          */
1638         local_bh_disable();
1639         bh_lock_sock(sk);
1640         BUG_TRAP(!sock_owned_by_user(sk));
1641
1642         /* Have we already been destroyed by a softirq or backlog? */
1643         if (state != TCP_CLOSE && sk->sk_state == TCP_CLOSE)
1644                 goto out;
1645
1646         /*      This is a (useful) BSD violating of the RFC. There is a
1647          *      problem with TCP as specified in that the other end could
1648          *      keep a socket open forever with no application left this end.
1649          *      We use a 3 minute timeout (about the same as BSD) then kill
1650          *      our end. If they send after that then tough - BUT: long enough
1651          *      that we won't make the old 4*rto = almost no time - whoops
1652          *      reset mistake.
1653          *
1654          *      Nope, it was not mistake. It is really desired behaviour
1655          *      f.e. on http servers, when such sockets are useless, but
1656          *      consume significant resources. Let's do it with special
1657          *      linger2 option.                                 --ANK
1658          */
1659
1660         if (sk->sk_state == TCP_FIN_WAIT2) {
1661                 struct tcp_sock *tp = tcp_sk(sk);
1662                 if (tp->linger2 < 0) {
1663                         tcp_set_state(sk, TCP_CLOSE);
1664                         tcp_send_active_reset(sk, GFP_ATOMIC);
1665                         NET_INC_STATS_BH(LINUX_MIB_TCPABORTONLINGER);
1666                 } else {
1667                         const int tmo = tcp_fin_time(sk);
1668
1669                         if (tmo > TCP_TIMEWAIT_LEN) {
1670                                 inet_csk_reset_keepalive_timer(sk,
1671                                                 tmo - TCP_TIMEWAIT_LEN);
1672                         } else {
1673                                 tcp_time_wait(sk, TCP_FIN_WAIT2, tmo);
1674                                 goto out;
1675                         }
1676                 }
1677         }
1678         if (sk->sk_state != TCP_CLOSE) {
1679                 sk_stream_mem_reclaim(sk);
1680                 if (atomic_read(sk->sk_prot->orphan_count) > sysctl_tcp_max_orphans ||
1681                     (sk->sk_wmem_queued > SOCK_MIN_SNDBUF &&
1682                      atomic_read(&tcp_memory_allocated) > sysctl_tcp_mem[2])) {
1683                         if (net_ratelimit())
1684                                 printk(KERN_INFO "TCP: too many of orphaned "
1685                                        "sockets\n");
1686                         tcp_set_state(sk, TCP_CLOSE);
1687                         tcp_send_active_reset(sk, GFP_ATOMIC);
1688                         NET_INC_STATS_BH(LINUX_MIB_TCPABORTONMEMORY);
1689                 }
1690         }
1691
1692         if (sk->sk_state == TCP_CLOSE)
1693                 inet_csk_destroy_sock(sk);
1694         /* Otherwise, socket is reprieved until protocol close. */
1695
1696 out:
1697         bh_unlock_sock(sk);
1698         local_bh_enable();
1699         sock_put(sk);
1700 }
1701
1702 /* These states need RST on ABORT according to RFC793 */
1703
1704 static inline int tcp_need_reset(int state)
1705 {
1706         return (1 << state) &
1707                (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT | TCPF_FIN_WAIT1 |
1708                 TCPF_FIN_WAIT2 | TCPF_SYN_RECV);
1709 }
1710
1711 int tcp_disconnect(struct sock *sk, int flags)
1712 {
1713         struct inet_sock *inet = inet_sk(sk);
1714         struct inet_connection_sock *icsk = inet_csk(sk);
1715         struct tcp_sock *tp = tcp_sk(sk);
1716         int err = 0;
1717         int old_state = sk->sk_state;
1718
1719         if (old_state != TCP_CLOSE)
1720                 tcp_set_state(sk, TCP_CLOSE);
1721
1722         /* ABORT function of RFC793 */
1723         if (old_state == TCP_LISTEN) {
1724                 inet_csk_listen_stop(sk);
1725         } else if (tcp_need_reset(old_state) ||
1726                    (tp->snd_nxt != tp->write_seq &&
1727                     (1 << old_state) & (TCPF_CLOSING | TCPF_LAST_ACK))) {
1728                 /* The last check adjusts for discrepancy of Linux wrt. RFC
1729                  * states
1730                  */
1731                 tcp_send_active_reset(sk, gfp_any());
1732                 sk->sk_err = ECONNRESET;
1733         } else if (old_state == TCP_SYN_SENT)
1734                 sk->sk_err = ECONNRESET;
1735
1736         tcp_clear_xmit_timers(sk);
1737         __skb_queue_purge(&sk->sk_receive_queue);
1738         tcp_write_queue_purge(sk);
1739         __skb_queue_purge(&tp->out_of_order_queue);
1740 #ifdef CONFIG_NET_DMA
1741         __skb_queue_purge(&sk->sk_async_wait_queue);
1742 #endif
1743
1744         inet->dport = 0;
1745
1746         if (!(sk->sk_userlocks & SOCK_BINDADDR_LOCK))
1747                 inet_reset_saddr(sk);
1748
1749         sk->sk_shutdown = 0;
1750         sock_reset_flag(sk, SOCK_DONE);
1751         tp->srtt = 0;
1752         if ((tp->write_seq += tp->max_window + 2) == 0)
1753                 tp->write_seq = 1;
1754         icsk->icsk_backoff = 0;
1755         tp->snd_cwnd = 2;
1756         icsk->icsk_probes_out = 0;
1757         tp->packets_out = 0;
1758         tp->snd_ssthresh = 0x7fffffff;
1759         tp->snd_cwnd_cnt = 0;
1760         tp->bytes_acked = 0;
1761         tcp_set_ca_state(sk, TCP_CA_Open);
1762         tcp_clear_retrans(tp);
1763         inet_csk_delack_init(sk);
1764         tcp_init_send_head(sk);
1765         tp->rx_opt.saw_tstamp = 0;
1766         tcp_sack_reset(&tp->rx_opt);
1767         __sk_dst_reset(sk);
1768
1769         BUG_TRAP(!inet->num || icsk->icsk_bind_hash);
1770
1771         sk->sk_error_report(sk);
1772         return err;
1773 }
1774
1775 /*
1776  *      Socket option code for TCP.
1777  */
1778 static int do_tcp_setsockopt(struct sock *sk, int level,
1779                 int optname, char __user *optval, int optlen)
1780 {
1781         struct tcp_sock *tp = tcp_sk(sk);
1782         struct inet_connection_sock *icsk = inet_csk(sk);
1783         int val;
1784         int err = 0;
1785
1786         /* This is a string value all the others are int's */
1787         if (optname == TCP_CONGESTION) {
1788                 char name[TCP_CA_NAME_MAX];
1789
1790                 if (optlen < 1)
1791                         return -EINVAL;
1792
1793                 val = strncpy_from_user(name, optval,
1794                                         min(TCP_CA_NAME_MAX-1, optlen));
1795                 if (val < 0)
1796                         return -EFAULT;
1797                 name[val] = 0;
1798
1799                 lock_sock(sk);
1800                 err = tcp_set_congestion_control(sk, name);
1801                 release_sock(sk);
1802                 return err;
1803         }
1804
1805         if (optlen < sizeof(int))
1806                 return -EINVAL;
1807
1808         if (get_user(val, (int __user *)optval))
1809                 return -EFAULT;
1810
1811         lock_sock(sk);
1812
1813         switch (optname) {
1814         case TCP_MAXSEG:
1815                 /* Values greater than interface MTU won't take effect. However
1816                  * at the point when this call is done we typically don't yet
1817                  * know which interface is going to be used */
1818                 if (val < 8 || val > MAX_TCP_WINDOW) {
1819                         err = -EINVAL;
1820                         break;
1821                 }
1822                 tp->rx_opt.user_mss = val;
1823                 break;
1824
1825         case TCP_NODELAY:
1826                 if (val) {
1827                         /* TCP_NODELAY is weaker than TCP_CORK, so that
1828                          * this option on corked socket is remembered, but
1829                          * it is not activated until cork is cleared.
1830                          *
1831                          * However, when TCP_NODELAY is set we make
1832                          * an explicit push, which overrides even TCP_CORK
1833                          * for currently queued segments.
1834                          */
1835                         tp->nonagle |= TCP_NAGLE_OFF|TCP_NAGLE_PUSH;
1836                         tcp_push_pending_frames(sk);
1837                 } else {
1838                         tp->nonagle &= ~TCP_NAGLE_OFF;
1839                 }
1840                 break;
1841
1842         case TCP_CORK:
1843                 /* When set indicates to always queue non-full frames.
1844                  * Later the user clears this option and we transmit
1845                  * any pending partial frames in the queue.  This is
1846                  * meant to be used alongside sendfile() to get properly
1847                  * filled frames when the user (for example) must write
1848                  * out headers with a write() call first and then use
1849                  * sendfile to send out the data parts.
1850                  *
1851                  * TCP_CORK can be set together with TCP_NODELAY and it is
1852                  * stronger than TCP_NODELAY.
1853                  */
1854                 if (val) {
1855                         tp->nonagle |= TCP_NAGLE_CORK;
1856                 } else {
1857                         tp->nonagle &= ~TCP_NAGLE_CORK;
1858                         if (tp->nonagle&TCP_NAGLE_OFF)
1859                                 tp->nonagle |= TCP_NAGLE_PUSH;
1860                         tcp_push_pending_frames(sk);
1861                 }
1862                 break;
1863
1864         case TCP_KEEPIDLE:
1865                 if (val < 1 || val > MAX_TCP_KEEPIDLE)
1866                         err = -EINVAL;
1867                 else {
1868                         tp->keepalive_time = val * HZ;
1869                         if (sock_flag(sk, SOCK_KEEPOPEN) &&
1870                             !((1 << sk->sk_state) &
1871                               (TCPF_CLOSE | TCPF_LISTEN))) {
1872                                 __u32 elapsed = tcp_time_stamp - tp->rcv_tstamp;
1873                                 if (tp->keepalive_time > elapsed)
1874                                         elapsed = tp->keepalive_time - elapsed;
1875                                 else
1876                                         elapsed = 0;
1877                                 inet_csk_reset_keepalive_timer(sk, elapsed);
1878                         }
1879                 }
1880                 break;
1881         case TCP_KEEPINTVL:
1882                 if (val < 1 || val > MAX_TCP_KEEPINTVL)
1883                         err = -EINVAL;
1884                 else
1885                         tp->keepalive_intvl = val * HZ;
1886                 break;
1887         case TCP_KEEPCNT:
1888                 if (val < 1 || val > MAX_TCP_KEEPCNT)
1889                         err = -EINVAL;
1890                 else
1891                         tp->keepalive_probes = val;
1892                 break;
1893         case TCP_SYNCNT:
1894                 if (val < 1 || val > MAX_TCP_SYNCNT)
1895                         err = -EINVAL;
1896                 else
1897                         icsk->icsk_syn_retries = val;
1898                 break;
1899
1900         case TCP_LINGER2:
1901                 if (val < 0)
1902                         tp->linger2 = -1;
1903                 else if (val > sysctl_tcp_fin_timeout / HZ)
1904                         tp->linger2 = 0;
1905                 else
1906                         tp->linger2 = val * HZ;
1907                 break;
1908
1909         case TCP_DEFER_ACCEPT:
1910                 icsk->icsk_accept_queue.rskq_defer_accept = 0;
1911                 if (val > 0) {
1912                         /* Translate value in seconds to number of
1913                          * retransmits */
1914                         while (icsk->icsk_accept_queue.rskq_defer_accept < 32 &&
1915                                val > ((TCP_TIMEOUT_INIT / HZ) <<
1916                                        icsk->icsk_accept_queue.rskq_defer_accept))
1917                                 icsk->icsk_accept_queue.rskq_defer_accept++;
1918                         icsk->icsk_accept_queue.rskq_defer_accept++;
1919                 }
1920                 break;
1921
1922         case TCP_WINDOW_CLAMP:
1923                 if (!val) {
1924                         if (sk->sk_state != TCP_CLOSE) {
1925                                 err = -EINVAL;
1926                                 break;
1927                         }
1928                         tp->window_clamp = 0;
1929                 } else
1930                         tp->window_clamp = val < SOCK_MIN_RCVBUF / 2 ?
1931                                                 SOCK_MIN_RCVBUF / 2 : val;
1932                 break;
1933
1934         case TCP_QUICKACK:
1935                 if (!val) {
1936                         icsk->icsk_ack.pingpong = 1;
1937                 } else {
1938                         icsk->icsk_ack.pingpong = 0;
1939                         if ((1 << sk->sk_state) &
1940                             (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT) &&
1941                             inet_csk_ack_scheduled(sk)) {
1942                                 icsk->icsk_ack.pending |= ICSK_ACK_PUSHED;
1943                                 tcp_cleanup_rbuf(sk, 1);
1944                                 if (!(val & 1))
1945                                         icsk->icsk_ack.pingpong = 1;
1946                         }
1947                 }
1948                 break;
1949
1950 #ifdef CONFIG_TCP_MD5SIG
1951         case TCP_MD5SIG:
1952                 /* Read the IP->Key mappings from userspace */
1953                 err = tp->af_specific->md5_parse(sk, optval, optlen);
1954                 break;
1955 #endif
1956
1957         default:
1958                 err = -ENOPROTOOPT;
1959                 break;
1960         }
1961
1962         release_sock(sk);
1963         return err;
1964 }
1965
1966 int tcp_setsockopt(struct sock *sk, int level, int optname, char __user *optval,
1967                    int optlen)
1968 {
1969         struct inet_connection_sock *icsk = inet_csk(sk);
1970
1971         if (level != SOL_TCP)
1972                 return icsk->icsk_af_ops->setsockopt(sk, level, optname,
1973                                                      optval, optlen);
1974         return do_tcp_setsockopt(sk, level, optname, optval, optlen);
1975 }
1976
1977 #ifdef CONFIG_COMPAT
1978 int compat_tcp_setsockopt(struct sock *sk, int level, int optname,
1979                           char __user *optval, int optlen)
1980 {
1981         if (level != SOL_TCP)
1982                 return inet_csk_compat_setsockopt(sk, level, optname,
1983                                                   optval, optlen);
1984         return do_tcp_setsockopt(sk, level, optname, optval, optlen);
1985 }
1986
1987 EXPORT_SYMBOL(compat_tcp_setsockopt);
1988 #endif
1989
1990 /* Return information about state of tcp endpoint in API format. */
1991 void tcp_get_info(struct sock *sk, struct tcp_info *info)
1992 {
1993         struct tcp_sock *tp = tcp_sk(sk);
1994         const struct inet_connection_sock *icsk = inet_csk(sk);
1995         u32 now = tcp_time_stamp;
1996
1997         memset(info, 0, sizeof(*info));
1998
1999         info->tcpi_state = sk->sk_state;
2000         info->tcpi_ca_state = icsk->icsk_ca_state;
2001         info->tcpi_retransmits = icsk->icsk_retransmits;
2002         info->tcpi_probes = icsk->icsk_probes_out;
2003         info->tcpi_backoff = icsk->icsk_backoff;
2004
2005         if (tp->rx_opt.tstamp_ok)
2006                 info->tcpi_options |= TCPI_OPT_TIMESTAMPS;
2007         if (tp->rx_opt.sack_ok)
2008                 info->tcpi_options |= TCPI_OPT_SACK;
2009         if (tp->rx_opt.wscale_ok) {
2010                 info->tcpi_options |= TCPI_OPT_WSCALE;
2011                 info->tcpi_snd_wscale = tp->rx_opt.snd_wscale;
2012                 info->tcpi_rcv_wscale = tp->rx_opt.rcv_wscale;
2013         }
2014
2015         if (tp->ecn_flags&TCP_ECN_OK)
2016                 info->tcpi_options |= TCPI_OPT_ECN;
2017
2018         info->tcpi_rto = jiffies_to_usecs(icsk->icsk_rto);
2019         info->tcpi_ato = jiffies_to_usecs(icsk->icsk_ack.ato);
2020         info->tcpi_snd_mss = tp->mss_cache;
2021         info->tcpi_rcv_mss = icsk->icsk_ack.rcv_mss;
2022
2023         info->tcpi_unacked = tp->packets_out;
2024         info->tcpi_sacked = tp->sacked_out;
2025         info->tcpi_lost = tp->lost_out;
2026         info->tcpi_retrans = tp->retrans_out;
2027         info->tcpi_fackets = tp->fackets_out;
2028
2029         info->tcpi_last_data_sent = jiffies_to_msecs(now - tp->lsndtime);
2030         info->tcpi_last_data_recv = jiffies_to_msecs(now - icsk->icsk_ack.lrcvtime);
2031         info->tcpi_last_ack_recv = jiffies_to_msecs(now - tp->rcv_tstamp);
2032
2033         info->tcpi_pmtu = icsk->icsk_pmtu_cookie;
2034         info->tcpi_rcv_ssthresh = tp->rcv_ssthresh;
2035         info->tcpi_rtt = jiffies_to_usecs(tp->srtt)>>3;
2036         info->tcpi_rttvar = jiffies_to_usecs(tp->mdev)>>2;
2037         info->tcpi_snd_ssthresh = tp->snd_ssthresh;
2038         info->tcpi_snd_cwnd = tp->snd_cwnd;
2039         info->tcpi_advmss = tp->advmss;
2040         info->tcpi_reordering = tp->reordering;
2041
2042         info->tcpi_rcv_rtt = jiffies_to_usecs(tp->rcv_rtt_est.rtt)>>3;
2043         info->tcpi_rcv_space = tp->rcvq_space.space;
2044
2045         info->tcpi_total_retrans = tp->total_retrans;
2046 }
2047
2048 EXPORT_SYMBOL_GPL(tcp_get_info);
2049
2050 static int do_tcp_getsockopt(struct sock *sk, int level,
2051                 int optname, char __user *optval, int __user *optlen)
2052 {
2053         struct inet_connection_sock *icsk = inet_csk(sk);
2054         struct tcp_sock *tp = tcp_sk(sk);
2055         int val, len;
2056
2057         if (get_user(len, optlen))
2058                 return -EFAULT;
2059
2060         len = min_t(unsigned int, len, sizeof(int));
2061
2062         if (len < 0)
2063                 return -EINVAL;
2064
2065         switch (optname) {
2066         case TCP_MAXSEG:
2067                 val = tp->mss_cache;
2068                 if (!val && ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN)))
2069                         val = tp->rx_opt.user_mss;
2070                 break;
2071         case TCP_NODELAY:
2072                 val = !!(tp->nonagle&TCP_NAGLE_OFF);
2073                 break;
2074         case TCP_CORK:
2075                 val = !!(tp->nonagle&TCP_NAGLE_CORK);
2076                 break;
2077         case TCP_KEEPIDLE:
2078                 val = (tp->keepalive_time ? : sysctl_tcp_keepalive_time) / HZ;
2079                 break;
2080         case TCP_KEEPINTVL:
2081                 val = (tp->keepalive_intvl ? : sysctl_tcp_keepalive_intvl) / HZ;
2082                 break;
2083         case TCP_KEEPCNT:
2084                 val = tp->keepalive_probes ? : sysctl_tcp_keepalive_probes;
2085                 break;
2086         case TCP_SYNCNT:
2087                 val = icsk->icsk_syn_retries ? : sysctl_tcp_syn_retries;
2088                 break;
2089         case TCP_LINGER2:
2090                 val = tp->linger2;
2091                 if (val >= 0)
2092                         val = (val ? : sysctl_tcp_fin_timeout) / HZ;
2093                 break;
2094         case TCP_DEFER_ACCEPT:
2095                 val = !icsk->icsk_accept_queue.rskq_defer_accept ? 0 :
2096                         ((TCP_TIMEOUT_INIT / HZ) << (icsk->icsk_accept_queue.rskq_defer_accept - 1));
2097                 break;
2098         case TCP_WINDOW_CLAMP:
2099                 val = tp->window_clamp;
2100                 break;
2101         case TCP_INFO: {
2102                 struct tcp_info info;
2103
2104                 if (get_user(len, optlen))
2105                         return -EFAULT;
2106
2107                 tcp_get_info(sk, &info);
2108
2109                 len = min_t(unsigned int, len, sizeof(info));
2110                 if (put_user(len, optlen))
2111                         return -EFAULT;
2112                 if (copy_to_user(optval, &info, len))
2113                         return -EFAULT;
2114                 return 0;
2115         }
2116         case TCP_QUICKACK:
2117                 val = !icsk->icsk_ack.pingpong;
2118                 break;
2119
2120         case TCP_CONGESTION:
2121                 if (get_user(len, optlen))
2122                         return -EFAULT;
2123                 len = min_t(unsigned int, len, TCP_CA_NAME_MAX);
2124                 if (put_user(len, optlen))
2125                         return -EFAULT;
2126                 if (copy_to_user(optval, icsk->icsk_ca_ops->name, len))
2127                         return -EFAULT;
2128                 return 0;
2129         default:
2130                 return -ENOPROTOOPT;
2131         }
2132
2133         if (put_user(len, optlen))
2134                 return -EFAULT;
2135         if (copy_to_user(optval, &val, len))
2136                 return -EFAULT;
2137         return 0;
2138 }
2139
2140 int tcp_getsockopt(struct sock *sk, int level, int optname, char __user *optval,
2141                    int __user *optlen)
2142 {
2143         struct inet_connection_sock *icsk = inet_csk(sk);
2144
2145         if (level != SOL_TCP)
2146                 return icsk->icsk_af_ops->getsockopt(sk, level, optname,
2147                                                      optval, optlen);
2148         return do_tcp_getsockopt(sk, level, optname, optval, optlen);
2149 }
2150
2151 #ifdef CONFIG_COMPAT
2152 int compat_tcp_getsockopt(struct sock *sk, int level, int optname,
2153                           char __user *optval, int __user *optlen)
2154 {
2155         if (level != SOL_TCP)
2156                 return inet_csk_compat_getsockopt(sk, level, optname,
2157                                                   optval, optlen);
2158         return do_tcp_getsockopt(sk, level, optname, optval, optlen);
2159 }
2160
2161 EXPORT_SYMBOL(compat_tcp_getsockopt);
2162 #endif
2163
2164 struct sk_buff *tcp_tso_segment(struct sk_buff *skb, int features)
2165 {
2166         struct sk_buff *segs = ERR_PTR(-EINVAL);
2167         struct tcphdr *th;
2168         unsigned thlen;
2169         unsigned int seq;
2170         __be32 delta;
2171         unsigned int oldlen;
2172         unsigned int len;
2173
2174         if (!pskb_may_pull(skb, sizeof(*th)))
2175                 goto out;
2176
2177         th = tcp_hdr(skb);
2178         thlen = th->doff * 4;
2179         if (thlen < sizeof(*th))
2180                 goto out;
2181
2182         if (!pskb_may_pull(skb, thlen))
2183                 goto out;
2184
2185         oldlen = (u16)~skb->len;
2186         __skb_pull(skb, thlen);
2187
2188         if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) {
2189                 /* Packet is from an untrusted source, reset gso_segs. */
2190                 int type = skb_shinfo(skb)->gso_type;
2191                 int mss;
2192
2193                 if (unlikely(type &
2194                              ~(SKB_GSO_TCPV4 |
2195                                SKB_GSO_DODGY |
2196                                SKB_GSO_TCP_ECN |
2197                                SKB_GSO_TCPV6 |
2198                                0) ||
2199                              !(type & (SKB_GSO_TCPV4 | SKB_GSO_TCPV6))))
2200                         goto out;
2201
2202                 mss = skb_shinfo(skb)->gso_size;
2203                 skb_shinfo(skb)->gso_segs = (skb->len + mss - 1) / mss;
2204
2205                 segs = NULL;
2206                 goto out;
2207         }
2208
2209         segs = skb_segment(skb, features);
2210         if (IS_ERR(segs))
2211                 goto out;
2212
2213         len = skb_shinfo(skb)->gso_size;
2214         delta = htonl(oldlen + (thlen + len));
2215
2216         skb = segs;
2217         th = tcp_hdr(skb);
2218         seq = ntohl(th->seq);
2219
2220         do {
2221                 th->fin = th->psh = 0;
2222
2223                 th->check = ~csum_fold((__force __wsum)((__force u32)th->check +
2224                                        (__force u32)delta));
2225                 if (skb->ip_summed != CHECKSUM_PARTIAL)
2226                         th->check =
2227                              csum_fold(csum_partial(skb_transport_header(skb),
2228                                                     thlen, skb->csum));
2229
2230                 seq += len;
2231                 skb = skb->next;
2232                 th = tcp_hdr(skb);
2233
2234                 th->seq = htonl(seq);
2235                 th->cwr = 0;
2236         } while (skb->next);
2237
2238         delta = htonl(oldlen + (skb->tail - skb->transport_header) +
2239                       skb->data_len);
2240         th->check = ~csum_fold((__force __wsum)((__force u32)th->check +
2241                                 (__force u32)delta));
2242         if (skb->ip_summed != CHECKSUM_PARTIAL)
2243                 th->check = csum_fold(csum_partial(skb_transport_header(skb),
2244                                                    thlen, skb->csum));
2245
2246 out:
2247         return segs;
2248 }
2249 EXPORT_SYMBOL(tcp_tso_segment);
2250
2251 #ifdef CONFIG_TCP_MD5SIG
2252 static unsigned long tcp_md5sig_users;
2253 static struct tcp_md5sig_pool **tcp_md5sig_pool;
2254 static DEFINE_SPINLOCK(tcp_md5sig_pool_lock);
2255
2256 static void __tcp_free_md5sig_pool(struct tcp_md5sig_pool **pool)
2257 {
2258         int cpu;
2259         for_each_possible_cpu(cpu) {
2260                 struct tcp_md5sig_pool *p = *per_cpu_ptr(pool, cpu);
2261                 if (p) {
2262                         if (p->md5_desc.tfm)
2263                                 crypto_free_hash(p->md5_desc.tfm);
2264                         kfree(p);
2265                         p = NULL;
2266                 }
2267         }
2268         free_percpu(pool);
2269 }
2270
2271 void tcp_free_md5sig_pool(void)
2272 {
2273         struct tcp_md5sig_pool **pool = NULL;
2274
2275         spin_lock_bh(&tcp_md5sig_pool_lock);
2276         if (--tcp_md5sig_users == 0) {
2277                 pool = tcp_md5sig_pool;
2278                 tcp_md5sig_pool = NULL;
2279         }
2280         spin_unlock_bh(&tcp_md5sig_pool_lock);
2281         if (pool)
2282                 __tcp_free_md5sig_pool(pool);
2283 }
2284
2285 EXPORT_SYMBOL(tcp_free_md5sig_pool);
2286
2287 static struct tcp_md5sig_pool **__tcp_alloc_md5sig_pool(void)
2288 {
2289         int cpu;
2290         struct tcp_md5sig_pool **pool;
2291
2292         pool = alloc_percpu(struct tcp_md5sig_pool *);
2293         if (!pool)
2294                 return NULL;
2295
2296         for_each_possible_cpu(cpu) {
2297                 struct tcp_md5sig_pool *p;
2298                 struct crypto_hash *hash;
2299
2300                 p = kzalloc(sizeof(*p), GFP_KERNEL);
2301                 if (!p)
2302                         goto out_free;
2303                 *per_cpu_ptr(pool, cpu) = p;
2304
2305                 hash = crypto_alloc_hash("md5", 0, CRYPTO_ALG_ASYNC);
2306                 if (!hash || IS_ERR(hash))
2307                         goto out_free;
2308
2309                 p->md5_desc.tfm = hash;
2310         }
2311         return pool;
2312 out_free:
2313         __tcp_free_md5sig_pool(pool);
2314         return NULL;
2315 }
2316
2317 struct tcp_md5sig_pool **tcp_alloc_md5sig_pool(void)
2318 {
2319         struct tcp_md5sig_pool **pool;
2320         int alloc = 0;
2321
2322 retry:
2323         spin_lock_bh(&tcp_md5sig_pool_lock);
2324         pool = tcp_md5sig_pool;
2325         if (tcp_md5sig_users++ == 0) {
2326                 alloc = 1;
2327                 spin_unlock_bh(&tcp_md5sig_pool_lock);
2328         } else if (!pool) {
2329                 tcp_md5sig_users--;
2330                 spin_unlock_bh(&tcp_md5sig_pool_lock);
2331                 cpu_relax();
2332                 goto retry;
2333         } else
2334                 spin_unlock_bh(&tcp_md5sig_pool_lock);
2335
2336         if (alloc) {
2337                 /* we cannot hold spinlock here because this may sleep. */
2338                 struct tcp_md5sig_pool **p = __tcp_alloc_md5sig_pool();
2339                 spin_lock_bh(&tcp_md5sig_pool_lock);
2340                 if (!p) {
2341                         tcp_md5sig_users--;
2342                         spin_unlock_bh(&tcp_md5sig_pool_lock);
2343                         return NULL;
2344                 }
2345                 pool = tcp_md5sig_pool;
2346                 if (pool) {
2347                         /* oops, it has already been assigned. */
2348                         spin_unlock_bh(&tcp_md5sig_pool_lock);
2349                         __tcp_free_md5sig_pool(p);
2350                 } else {
2351                         tcp_md5sig_pool = pool = p;
2352                         spin_unlock_bh(&tcp_md5sig_pool_lock);
2353                 }
2354         }
2355         return pool;
2356 }
2357
2358 EXPORT_SYMBOL(tcp_alloc_md5sig_pool);
2359
2360 struct tcp_md5sig_pool *__tcp_get_md5sig_pool(int cpu)
2361 {
2362         struct tcp_md5sig_pool **p;
2363         spin_lock_bh(&tcp_md5sig_pool_lock);
2364         p = tcp_md5sig_pool;
2365         if (p)
2366                 tcp_md5sig_users++;
2367         spin_unlock_bh(&tcp_md5sig_pool_lock);
2368         return (p ? *per_cpu_ptr(p, cpu) : NULL);
2369 }
2370
2371 EXPORT_SYMBOL(__tcp_get_md5sig_pool);
2372
2373 void __tcp_put_md5sig_pool(void)
2374 {
2375         tcp_free_md5sig_pool();
2376 }
2377
2378 EXPORT_SYMBOL(__tcp_put_md5sig_pool);
2379 #endif
2380
2381 void tcp_done(struct sock *sk)
2382 {
2383         if(sk->sk_state == TCP_SYN_SENT || sk->sk_state == TCP_SYN_RECV)
2384                 TCP_INC_STATS_BH(TCP_MIB_ATTEMPTFAILS);
2385
2386         tcp_set_state(sk, TCP_CLOSE);
2387         tcp_clear_xmit_timers(sk);
2388
2389         sk->sk_shutdown = SHUTDOWN_MASK;
2390
2391         if (!sock_flag(sk, SOCK_DEAD))
2392                 sk->sk_state_change(sk);
2393         else
2394                 inet_csk_destroy_sock(sk);
2395 }
2396 EXPORT_SYMBOL_GPL(tcp_done);
2397
2398 extern void __skb_cb_too_small_for_tcp(int, int);
2399 extern struct tcp_congestion_ops tcp_reno;
2400
2401 static __initdata unsigned long thash_entries;
2402 static int __init set_thash_entries(char *str)
2403 {
2404         if (!str)
2405                 return 0;
2406         thash_entries = simple_strtoul(str, &str, 0);
2407         return 1;
2408 }
2409 __setup("thash_entries=", set_thash_entries);
2410
2411 void __init tcp_init(void)
2412 {
2413         struct sk_buff *skb = NULL;
2414         unsigned long limit;
2415         int order, i, max_share;
2416
2417         if (sizeof(struct tcp_skb_cb) > sizeof(skb->cb))
2418                 __skb_cb_too_small_for_tcp(sizeof(struct tcp_skb_cb),
2419                                            sizeof(skb->cb));
2420
2421         tcp_hashinfo.bind_bucket_cachep =
2422                 kmem_cache_create("tcp_bind_bucket",
2423                                   sizeof(struct inet_bind_bucket), 0,
2424                                   SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL);
2425
2426         /* Size and allocate the main established and bind bucket
2427          * hash tables.
2428          *
2429          * The methodology is similar to that of the buffer cache.
2430          */
2431         tcp_hashinfo.ehash =
2432                 alloc_large_system_hash("TCP established",
2433                                         sizeof(struct inet_ehash_bucket),
2434                                         thash_entries,
2435                                         (num_physpages >= 128 * 1024) ?
2436                                         13 : 15,
2437                                         0,
2438                                         &tcp_hashinfo.ehash_size,
2439                                         NULL,
2440                                         0);
2441         tcp_hashinfo.ehash_size = 1 << tcp_hashinfo.ehash_size;
2442         for (i = 0; i < tcp_hashinfo.ehash_size; i++) {
2443                 rwlock_init(&tcp_hashinfo.ehash[i].lock);
2444                 INIT_HLIST_HEAD(&tcp_hashinfo.ehash[i].chain);
2445                 INIT_HLIST_HEAD(&tcp_hashinfo.ehash[i].twchain);
2446         }
2447
2448         tcp_hashinfo.bhash =
2449                 alloc_large_system_hash("TCP bind",
2450                                         sizeof(struct inet_bind_hashbucket),
2451                                         tcp_hashinfo.ehash_size,
2452                                         (num_physpages >= 128 * 1024) ?
2453                                         13 : 15,
2454                                         0,
2455                                         &tcp_hashinfo.bhash_size,
2456                                         NULL,
2457                                         64 * 1024);
2458         tcp_hashinfo.bhash_size = 1 << tcp_hashinfo.bhash_size;
2459         for (i = 0; i < tcp_hashinfo.bhash_size; i++) {
2460                 spin_lock_init(&tcp_hashinfo.bhash[i].lock);
2461                 INIT_HLIST_HEAD(&tcp_hashinfo.bhash[i].chain);
2462         }
2463
2464         /* Try to be a bit smarter and adjust defaults depending
2465          * on available memory.
2466          */
2467         for (order = 0; ((1 << order) << PAGE_SHIFT) <
2468                         (tcp_hashinfo.bhash_size * sizeof(struct inet_bind_hashbucket));
2469                         order++)
2470                 ;
2471         if (order >= 4) {
2472                 sysctl_local_port_range[0] = 32768;
2473                 sysctl_local_port_range[1] = 61000;
2474                 tcp_death_row.sysctl_max_tw_buckets = 180000;
2475                 sysctl_tcp_max_orphans = 4096 << (order - 4);
2476                 sysctl_max_syn_backlog = 1024;
2477         } else if (order < 3) {
2478                 sysctl_local_port_range[0] = 1024 * (3 - order);
2479                 tcp_death_row.sysctl_max_tw_buckets >>= (3 - order);
2480                 sysctl_tcp_max_orphans >>= (3 - order);
2481                 sysctl_max_syn_backlog = 128;
2482         }
2483
2484         /* Set the pressure threshold to be a fraction of global memory that
2485          * is up to 1/2 at 256 MB, decreasing toward zero with the amount of
2486          * memory, with a floor of 128 pages.
2487          */
2488         limit = min(nr_all_pages, 1UL<<(28-PAGE_SHIFT)) >> (20-PAGE_SHIFT);
2489         limit = (limit * (nr_all_pages >> (20-PAGE_SHIFT))) >> (PAGE_SHIFT-11);
2490         limit = max(limit, 128UL);
2491         sysctl_tcp_mem[0] = limit / 4 * 3;
2492         sysctl_tcp_mem[1] = limit;
2493         sysctl_tcp_mem[2] = sysctl_tcp_mem[0] * 2;
2494
2495         /* Set per-socket limits to no more than 1/128 the pressure threshold */
2496         limit = ((unsigned long)sysctl_tcp_mem[1]) << (PAGE_SHIFT - 7);
2497         max_share = min(4UL*1024*1024, limit);
2498
2499         sysctl_tcp_wmem[0] = SK_STREAM_MEM_QUANTUM;
2500         sysctl_tcp_wmem[1] = 16*1024;
2501         sysctl_tcp_wmem[2] = max(64*1024, max_share);
2502
2503         sysctl_tcp_rmem[0] = SK_STREAM_MEM_QUANTUM;
2504         sysctl_tcp_rmem[1] = 87380;
2505         sysctl_tcp_rmem[2] = max(87380, max_share);
2506
2507         printk(KERN_INFO "TCP: Hash tables configured "
2508                "(established %d bind %d)\n",
2509                tcp_hashinfo.ehash_size, tcp_hashinfo.bhash_size);
2510
2511         tcp_register_congestion_control(&tcp_reno);
2512 }
2513
2514 EXPORT_SYMBOL(tcp_close);
2515 EXPORT_SYMBOL(tcp_disconnect);
2516 EXPORT_SYMBOL(tcp_getsockopt);
2517 EXPORT_SYMBOL(tcp_ioctl);
2518 EXPORT_SYMBOL(tcp_poll);
2519 EXPORT_SYMBOL(tcp_read_sock);
2520 EXPORT_SYMBOL(tcp_recvmsg);
2521 EXPORT_SYMBOL(tcp_sendmsg);
2522 EXPORT_SYMBOL(tcp_sendpage);
2523 EXPORT_SYMBOL(tcp_setsockopt);
2524 EXPORT_SYMBOL(tcp_shutdown);
2525 EXPORT_SYMBOL(tcp_statistics);