SAFE public projects git trees. - safe/jmp/linux-2.6/blob - net/ipv4/tcp.c

   1 /*
   2  * INET         An implementation of the TCP/IP protocol suite for the LINUX
   3  *              operating system.  INET is implemented using the  BSD Socket
   4  *              interface as the means of communication with the user level.
   5  *
   6  *              Implementation of the Transmission Control Protocol(TCP).
   7  *
   8  * Version:     $Id: tcp.c,v 1.216 2002/02/01 22:01:04 davem Exp $
   9  *
  10  * Authors:     Ross Biro
  11  *              Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
  12  *              Mark Evans, <evansmp@uhura.aston.ac.uk>
  13  *              Corey Minyard <wf-rch!minyard@relay.EU.net>
  14  *              Florian La Roche, <flla@stud.uni-sb.de>
  15  *              Charles Hedrick, <hedrick@klinzhai.rutgers.edu>
  16  *              Linus Torvalds, <torvalds@cs.helsinki.fi>
  17  *              Alan Cox, <gw4pts@gw4pts.ampr.org>
  18  *              Matthew Dillon, <dillon@apollo.west.oic.com>
  19  *              Arnt Gulbrandsen, <agulbra@nvg.unit.no>
  20  *              Jorge Cwik, <jorge@laser.satlink.net>
  21  *
  22  * Fixes:
  23  *              Alan Cox        :       Numerous verify_area() calls
  24  *              Alan Cox        :       Set the ACK bit on a reset
  25  *              Alan Cox        :       Stopped it crashing if it closed while
  26  *                                      sk->inuse=1 and was trying to connect
  27  *                                      (tcp_err()).
  28  *              Alan Cox        :       All icmp error handling was broken
  29  *                                      pointers passed where wrong and the
  30  *                                      socket was looked up backwards. Nobody
  31  *                                      tested any icmp error code obviously.
  32  *              Alan Cox        :       tcp_err() now handled properly. It
  33  *                                      wakes people on errors. poll
  34  *                                      behaves and the icmp error race
  35  *                                      has gone by moving it into sock.c
  36  *              Alan Cox        :       tcp_send_reset() fixed to work for
  37  *                                      everything not just packets for
  38  *                                      unknown sockets.
  39  *              Alan Cox        :       tcp option processing.
  40  *              Alan Cox        :       Reset tweaked (still not 100%) [Had
  41  *                                      syn rule wrong]
  42  *              Herp Rosmanith  :       More reset fixes
  43  *              Alan Cox        :       No longer acks invalid rst frames.
  44  *                                      Acking any kind of RST is right out.
  45  *              Alan Cox        :       Sets an ignore me flag on an rst
  46  *                                      receive otherwise odd bits of prattle
  47  *                                      escape still
  48  *              Alan Cox        :       Fixed another acking RST frame bug.
  49  *                                      Should stop LAN workplace lockups.
  50  *              Alan Cox        :       Some tidyups using the new skb list
  51  *                                      facilities
  52  *              Alan Cox        :       sk->keepopen now seems to work
  53  *              Alan Cox        :       Pulls options out correctly on accepts
  54  *              Alan Cox        :       Fixed assorted sk->rqueue->next errors
  55  *              Alan Cox        :       PSH doesn't end a TCP read. Switched a
  56  *                                      bit to skb ops.
  57  *              Alan Cox        :       Tidied tcp_data to avoid a potential
  58  *                                      nasty.
  59  *              Alan Cox        :       Added some better commenting, as the
  60  *                                      tcp is hard to follow
  61  *              Alan Cox        :       Removed incorrect check for 20 * psh
  62  *      Michael O'Reilly        :       ack < copied bug fix.
  63  *      Johannes Stille         :       Misc tcp fixes (not all in yet).
  64  *              Alan Cox        :       FIN with no memory -> CRASH
  65  *              Alan Cox        :       Added socket option proto entries.
  66  *                                      Also added awareness of them to accept.
  67  *              Alan Cox        :       Added TCP options (SOL_TCP)
  68  *              Alan Cox        :       Switched wakeup calls to callbacks,
  69  *                                      so the kernel can layer network
  70  *                                      sockets.
  71  *              Alan Cox        :       Use ip_tos/ip_ttl settings.
  72  *              Alan Cox        :       Handle FIN (more) properly (we hope).
  73  *              Alan Cox        :       RST frames sent on unsynchronised
  74  *                                      state ack error.
  75  *              Alan Cox        :       Put in missing check for SYN bit.
  76  *              Alan Cox        :       Added tcp_select_window() aka NET2E
  77  *                                      window non shrink trick.
  78  *              Alan Cox        :       Added a couple of small NET2E timer
  79  *                                      fixes
  80  *              Charles Hedrick :       TCP fixes
  81  *              Toomas Tamm     :       TCP window fixes
  82  *              Alan Cox        :       Small URG fix to rlogin ^C ack fight
  83  *              Charles Hedrick :       Rewrote most of it to actually work
  84  *              Linus           :       Rewrote tcp_read() and URG handling
  85  *                                      completely
  86  *              Gerhard Koerting:       Fixed some missing timer handling
  87  *              Matthew Dillon  :       Reworked TCP machine states as per RFC
  88  *              Gerhard Koerting:       PC/TCP workarounds
  89  *              Adam Caldwell   :       Assorted timer/timing errors
  90  *              Matthew Dillon  :       Fixed another RST bug
  91  *              Alan Cox        :       Move to kernel side addressing changes.
  92  *              Alan Cox        :       Beginning work on TCP fastpathing
  93  *                                      (not yet usable)
  94  *              Arnt Gulbrandsen:       Turbocharged tcp_check() routine.
  95  *              Alan Cox        :       TCP fast path debugging
  96  *              Alan Cox        :       Window clamping
  97  *              Michael Riepe   :       Bug in tcp_check()
  98  *              Matt Dillon     :       More TCP improvements and RST bug fixes
  99  *              Matt Dillon     :       Yet more small nasties remove from the
 100  *                                      TCP code (Be very nice to this man if
 101  *                                      tcp finally works 100%) 8)
 102  *              Alan Cox        :       BSD accept semantics.
 103  *              Alan Cox        :       Reset on closedown bug.
 104  *      Peter De Schrijver      :       ENOTCONN check missing in tcp_sendto().
 105  *              Michael Pall    :       Handle poll() after URG properly in
 106  *                                      all cases.
 107  *              Michael Pall    :       Undo the last fix in tcp_read_urg()
 108  *                                      (multi URG PUSH broke rlogin).
 109  *              Michael Pall    :       Fix the multi URG PUSH problem in
 110  *                                      tcp_readable(), poll() after URG
 111  *                                      works now.
 112  *              Michael Pall    :       recv(...,MSG_OOB) never blocks in the
 113  *                                      BSD api.
 114  *              Alan Cox        :       Changed the semantics of sk->socket to
 115  *                                      fix a race and a signal problem with
 116  *                                      accept() and async I/O.
 117  *              Alan Cox        :       Relaxed the rules on tcp_sendto().
 118  *              Yury Shevchuk   :       Really fixed accept() blocking problem.
 119  *              Craig I. Hagan  :       Allow for BSD compatible TIME_WAIT for
 120  *                                      clients/servers which listen in on
 121  *                                      fixed ports.
 122  *              Alan Cox        :       Cleaned the above up and shrank it to
 123  *                                      a sensible code size.
 124  *              Alan Cox        :       Self connect lockup fix.
 125  *              Alan Cox        :       No connect to multicast.
 126  *              Ross Biro       :       Close unaccepted children on master
 127  *                                      socket close.
 128  *              Alan Cox        :       Reset tracing code.
 129  *              Alan Cox        :       Spurious resets on shutdown.
 130  *              Alan Cox        :       Giant 15 minute/60 second timer error
 131  *              Alan Cox        :       Small whoops in polling before an
 132  *                                      accept.
 133  *              Alan Cox        :       Kept the state trace facility since
 134  *                                      it's handy for debugging.
 135  *              Alan Cox        :       More reset handler fixes.
 136  *              Alan Cox        :       Started rewriting the code based on
 137  *                                      the RFC's for other useful protocol
 138  *                                      references see: Comer, KA9Q NOS, and
 139  *                                      for a reference on the difference
 140  *                                      between specifications and how BSD
 141  *                                      works see the 4.4lite source.
 142  *              A.N.Kuznetsov   :       Don't time wait on completion of tidy
 143  *                                      close.
 144  *              Linus Torvalds  :       Fin/Shutdown & copied_seq changes.
 145  *              Linus Torvalds  :       Fixed BSD port reuse to work first syn
 146  *              Alan Cox        :       Reimplemented timers as per the RFC
 147  *                                      and using multiple timers for sanity.
 148  *              Alan Cox        :       Small bug fixes, and a lot of new
 149  *                                      comments.
 150  *              Alan Cox        :       Fixed dual reader crash by locking
 151  *                                      the buffers (much like datagram.c)
 152  *              Alan Cox        :       Fixed stuck sockets in probe. A probe
 153  *                                      now gets fed up of retrying without
 154  *                                      (even a no space) answer.
 155  *              Alan Cox        :       Extracted closing code better
 156  *              Alan Cox        :       Fixed the closing state machine to
 157  *                                      resemble the RFC.
 158  *              Alan Cox        :       More 'per spec' fixes.
 159  *              Jorge Cwik      :       Even faster checksumming.
 160  *              Alan Cox        :       tcp_data() doesn't ack illegal PSH
 161  *                                      only frames. At least one pc tcp stack
 162  *                                      generates them.
 163  *              Alan Cox        :       Cache last socket.
 164  *              Alan Cox        :       Per route irtt.
 165  *              Matt Day        :       poll()->select() match BSD precisely on error
 166  *              Alan Cox        :       New buffers
 167  *              Marc Tamsky     :       Various sk->prot->retransmits and
 168  *                                      sk->retransmits misupdating fixed.
 169  *                                      Fixed tcp_write_timeout: stuck close,
 170  *                                      and TCP syn retries gets used now.
 171  *              Mark Yarvis     :       In tcp_read_wakeup(), don't send an
 172  *                                      ack if state is TCP_CLOSED.
 173  *              Alan Cox        :       Look up device on a retransmit - routes may
 174  *                                      change. Doesn't yet cope with MSS shrink right
 175  *                                      but it's a start!
 176  *              Marc Tamsky     :       Closing in closing fixes.
 177  *              Mike Shaver     :       RFC1122 verifications.
 178  *              Alan Cox        :       rcv_saddr errors.
 179  *              Alan Cox        :       Block double connect().
 180  *              Alan Cox        :       Small hooks for enSKIP.
 181  *              Alexey Kuznetsov:       Path MTU discovery.
 182  *              Alan Cox        :       Support soft errors.
 183  *              Alan Cox        :       Fix MTU discovery pathological case
 184  *                                      when the remote claims no mtu!
 185  *              Marc Tamsky     :       TCP_CLOSE fix.
 186  *              Colin (G3TNE)   :       Send a reset on syn ack replies in
 187  *                                      window but wrong (fixes NT lpd problems)
 188  *              Pedro Roque     :       Better TCP window handling, delayed ack.
 189  *              Joerg Reuter    :       No modification of locked buffers in
 190  *                                      tcp_do_retransmit()
 191  *              Eric Schenk     :       Changed receiver side silly window
 192  *                                      avoidance algorithm to BSD style
 193  *                                      algorithm. This doubles throughput
 194  *                                      against machines running Solaris,
 195  *                                      and seems to result in general
 196  *                                      improvement.
 197  *      Stefan Magdalinski      :       adjusted tcp_readable() to fix FIONREAD
 198  *      Willy Konynenberg       :       Transparent proxying support.
 199  *      Mike McLagan            :       Routing by source
 200  *              Keith Owens     :       Do proper merging with partial SKB's in
 201  *                                      tcp_do_sendmsg to avoid burstiness.
 202  *              Eric Schenk     :       Fix fast close down bug with
 203  *                                      shutdown() followed by close().
 204  *              Andi Kleen      :       Make poll agree with SIGIO
 205  *      Salvatore Sanfilippo    :       Support SO_LINGER with linger == 1 and
 206  *                                      lingertime == 0 (RFC 793 ABORT Call)
 207  *      Hirokazu Takahashi      :       Use copy_from_user() instead of
 208  *                                      csum_and_copy_from_user() if possible.
 209  *
 210  *              This program is free software; you can redistribute it and/or
 211  *              modify it under the terms of the GNU General Public License
 212  *              as published by the Free Software Foundation; either version
 213  *              2 of the License, or(at your option) any later version.
 214  *
 215  * Description of States:
 216  *
 217  *      TCP_SYN_SENT            sent a connection request, waiting for ack
 218  *
 219  *      TCP_SYN_RECV            received a connection request, sent ack,
 220  *                              waiting for final ack in three-way handshake.
 221  *
 222  *      TCP_ESTABLISHED         connection established
 223  *
 224  *      TCP_FIN_WAIT1           our side has shutdown, waiting to complete
 225  *                              transmission of remaining buffered data
 226  *
 227  *      TCP_FIN_WAIT2           all buffered data sent, waiting for remote
 228  *                              to shutdown
 229  *
 230  *      TCP_CLOSING             both sides have shutdown but we still have
 231  *                              data we have to finish sending
 232  *
 233  *      TCP_TIME_WAIT           timeout to catch resent junk before entering
 234  *                              closed, can only be entered from FIN_WAIT2
 235  *                              or CLOSING.  Required because the other end
 236  *                              may not have gotten our last ACK causing it
 237  *                              to retransmit the data packet (which we ignore)
 238  *
 239  *      TCP_CLOSE_WAIT          remote side has shutdown and is waiting for
 240  *                              us to finish writing our data and to shutdown
 241  *                              (we have to close() to move on to LAST_ACK)
 242  *
 243  *      TCP_LAST_ACK            out side has shutdown after remote has
 244  *                              shutdown.  There may still be data in our
 245  *                              buffer that we have to finish sending
 246  *
 247  *      TCP_CLOSE               socket is finished
 248  */
 249
 250 #include <linux/module.h>
 251 #include <linux/types.h>
 252 #include <linux/fcntl.h>
 253 #include <linux/poll.h>
 254 #include <linux/init.h>
 255 #include <linux/fs.h>
 256 #include <linux/random.h>
 257 #include <linux/bootmem.h>
 258 #include <linux/cache.h>
 259 #include <linux/err.h>
 260 #include <linux/crypto.h>
 261
 262 #include <net/icmp.h>
 263 #include <net/tcp.h>
 264 #include <net/xfrm.h>
 265 #include <net/ip.h>
 266 #include <net/netdma.h>
 267
 268 #include <asm/uaccess.h>
 269 #include <asm/ioctls.h>
 270
 271 int sysctl_tcp_fin_timeout __read_mostly = TCP_FIN_TIMEOUT;
 272
 273 DEFINE_SNMP_STAT(struct tcp_mib, tcp_statistics) __read_mostly;
 274
 275 atomic_t tcp_orphan_count = ATOMIC_INIT(0);
 276
 277 EXPORT_SYMBOL_GPL(tcp_orphan_count);
 278
 279 int sysctl_tcp_mem[3] __read_mostly;
 280 int sysctl_tcp_wmem[3] __read_mostly;
 281 int sysctl_tcp_rmem[3] __read_mostly;
 282
 283 EXPORT_SYMBOL(sysctl_tcp_mem);
 284 EXPORT_SYMBOL(sysctl_tcp_rmem);
 285 EXPORT_SYMBOL(sysctl_tcp_wmem);
 286
 287 atomic_t tcp_memory_allocated;  /* Current allocated memory. */
 288 atomic_t tcp_sockets_allocated; /* Current number of TCP sockets. */
 289
 290 EXPORT_SYMBOL(tcp_memory_allocated);
 291 EXPORT_SYMBOL(tcp_sockets_allocated);
 292
 293 /*
 294  * Pressure flag: try to collapse.
 295  * Technical note: it is used by multiple contexts non atomically.
 296  * All the sk_stream_mem_schedule() is of this nature: accounting
 297  * is strict, actions are advisory and have some latency.
 298  */
 299 int tcp_memory_pressure __read_mostly;
 300
 301 EXPORT_SYMBOL(tcp_memory_pressure);
 302
 303 void tcp_enter_memory_pressure(void)
 304 {
 305         if (!tcp_memory_pressure) {
 306                 NET_INC_STATS(LINUX_MIB_TCPMEMORYPRESSURES);
 307                 tcp_memory_pressure = 1;
 308         }
 309 }
 310
 311 EXPORT_SYMBOL(tcp_enter_memory_pressure);
 312
 313 /*
 314  *      Wait for a TCP event.
 315  *
 316  *      Note that we don't need to lock the socket, as the upper poll layers
 317  *      take care of normal races (between the test and the event) and we don't
 318  *      go look at any of the socket buffers directly.
 319  */
 320 unsigned int tcp_poll(struct file *file, struct socket *sock, poll_table *wait)
 321 {
 322         unsigned int mask;
 323         struct sock *sk = sock->sk;
 324         struct tcp_sock *tp = tcp_sk(sk);
 325
 326         poll_wait(file, sk->sk_sleep, wait);
 327         if (sk->sk_state == TCP_LISTEN)
 328                 return inet_csk_listen_poll(sk);
 329
 330         /* Socket is not locked. We are protected from async events
 331            by poll logic and correct handling of state changes
 332            made by another threads is impossible in any case.
 333          */
 334
 335         mask = 0;
 336         if (sk->sk_err)
 337                 mask = POLLERR;
 338
 339         /*
 340          * POLLHUP is certainly not done right. But poll() doesn't
 341          * have a notion of HUP in just one direction, and for a
 342          * socket the read side is more interesting.
 343          *
 344          * Some poll() documentation says that POLLHUP is incompatible
 345          * with the POLLOUT/POLLWR flags, so somebody should check this
 346          * all. But careful, it tends to be safer to return too many
 347          * bits than too few, and you can easily break real applications
 348          * if you don't tell them that something has hung up!
 349          *
 350          * Check-me.
 351          *
 352          * Check number 1. POLLHUP is _UNMASKABLE_ event (see UNIX98 and
 353          * our fs/select.c). It means that after we received EOF,
 354          * poll always returns immediately, making impossible poll() on write()
 355          * in state CLOSE_WAIT. One solution is evident --- to set POLLHUP
 356          * if and only if shutdown has been made in both directions.
 357          * Actually, it is interesting to look how Solaris and DUX
 358          * solve this dilemma. I would prefer, if PULLHUP were maskable,
 359          * then we could set it on SND_SHUTDOWN. BTW examples given
 360          * in Stevens' books assume exactly this behaviour, it explains
 361          * why PULLHUP is incompatible with POLLOUT.    --ANK
 362          *
 363          * NOTE. Check for TCP_CLOSE is added. The goal is to prevent
 364          * blocking on fresh not-connected or disconnected socket. --ANK
 365          */
 366         if (sk->sk_shutdown == SHUTDOWN_MASK || sk->sk_state == TCP_CLOSE)
 367                 mask |= POLLHUP;
 368         if (sk->sk_shutdown & RCV_SHUTDOWN)
 369                 mask |= POLLIN | POLLRDNORM | POLLRDHUP;
 370
 371         /* Connected? */
 372         if ((1 << sk->sk_state) & ~(TCPF_SYN_SENT | TCPF_SYN_RECV)) {
 373                 /* Potential race condition. If read of tp below will
 374                  * escape above sk->sk_state, we can be illegally awaken
 375                  * in SYN_* states. */
 376                 if ((tp->rcv_nxt != tp->copied_seq) &&
 377                     (tp->urg_seq != tp->copied_seq ||
 378                      tp->rcv_nxt != tp->copied_seq + 1 ||
 379                      sock_flag(sk, SOCK_URGINLINE) || !tp->urg_data))
 380                         mask |= POLLIN | POLLRDNORM;
 381
 382                 if (!(sk->sk_shutdown & SEND_SHUTDOWN)) {
 383                         if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk)) {
 384                                 mask |= POLLOUT | POLLWRNORM;
 385                         } else {  /* send SIGIO later */
 386                                 set_bit(SOCK_ASYNC_NOSPACE,
 387                                         &sk->sk_socket->flags);
 388                                 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
 389
 390                                 /* Race breaker. If space is freed after
 391                                  * wspace test but before the flags are set,
 392                                  * IO signal will be lost.
 393                                  */
 394                                 if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk))
 395                                         mask |= POLLOUT | POLLWRNORM;
 396                         }
 397                 }
 398
 399                 if (tp->urg_data & TCP_URG_VALID)
 400                         mask |= POLLPRI;
 401         }
 402         return mask;
 403 }
 404
 405 int tcp_ioctl(struct sock *sk, int cmd, unsigned long arg)
 406 {
 407         struct tcp_sock *tp = tcp_sk(sk);
 408         int answ;
 409
 410         switch (cmd) {
 411         case SIOCINQ:
 412                 if (sk->sk_state == TCP_LISTEN)
 413                         return -EINVAL;
 414
 415                 lock_sock(sk);
 416                 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
 417                         answ = 0;
 418                 else if (sock_flag(sk, SOCK_URGINLINE) ||
 419                          !tp->urg_data ||
 420                          before(tp->urg_seq, tp->copied_seq) ||
 421                          !before(tp->urg_seq, tp->rcv_nxt)) {
 422                         answ = tp->rcv_nxt - tp->copied_seq;
 423
 424                         /* Subtract 1, if FIN is in queue. */
 425                         if (answ && !skb_queue_empty(&sk->sk_receive_queue))
 426                                 answ -=
 427                        tcp_hdr((struct sk_buff *)sk->sk_receive_queue.prev)->fin;
 428                 } else
 429                         answ = tp->urg_seq - tp->copied_seq;
 430                 release_sock(sk);
 431                 break;
 432         case SIOCATMARK:
 433                 answ = tp->urg_data && tp->urg_seq == tp->copied_seq;
 434                 break;
 435         case SIOCOUTQ:
 436                 if (sk->sk_state == TCP_LISTEN)
 437                         return -EINVAL;
 438
 439                 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
 440                         answ = 0;
 441                 else
 442                         answ = tp->write_seq - tp->snd_una;
 443                 break;
 444         default:
 445                 return -ENOIOCTLCMD;
 446         }
 447
 448         return put_user(answ, (int __user *)arg);
 449 }
 450
 451 static inline void tcp_mark_push(struct tcp_sock *tp, struct sk_buff *skb)
 452 {
 453         TCP_SKB_CB(skb)->flags |= TCPCB_FLAG_PSH;
 454         tp->pushed_seq = tp->write_seq;
 455 }
 456
 457 static inline int forced_push(struct tcp_sock *tp)
 458 {
 459         return after(tp->write_seq, tp->pushed_seq + (tp->max_window >> 1));
 460 }
 461
 462 static inline void skb_entail(struct sock *sk, struct sk_buff *skb)
 463 {
 464         struct tcp_sock *tp = tcp_sk(sk);
 465         struct tcp_skb_cb *tcb = TCP_SKB_CB(skb);
 466
 467         skb->csum    = 0;
 468         tcb->seq     = tcb->end_seq = tp->write_seq;
 469         tcb->flags   = TCPCB_FLAG_ACK;
 470         tcb->sacked  = 0;
 471         skb_header_release(skb);
 472         tcp_add_write_queue_tail(sk, skb);
 473         sk_charge_skb(sk, skb);
 474         if (tp->nonagle & TCP_NAGLE_PUSH)
 475                 tp->nonagle &= ~TCP_NAGLE_PUSH;
 476 }
 477
 478 static inline void tcp_mark_urg(struct tcp_sock *tp, int flags,
 479                                 struct sk_buff *skb)
 480 {
 481         if (flags & MSG_OOB) {
 482                 tp->urg_mode = 1;
 483                 tp->snd_up = tp->write_seq;
 484                 TCP_SKB_CB(skb)->sacked |= TCPCB_URG;
 485         }
 486 }
 487
 488 static inline void tcp_push(struct sock *sk, int flags, int mss_now,
 489                             int nonagle)
 490 {
 491         struct tcp_sock *tp = tcp_sk(sk);
 492
 493         if (tcp_send_head(sk)) {
 494                 struct sk_buff *skb = tcp_write_queue_tail(sk);
 495                 if (!(flags & MSG_MORE) || forced_push(tp))
 496                         tcp_mark_push(tp, skb);
 497                 tcp_mark_urg(tp, flags, skb);
 498                 __tcp_push_pending_frames(sk, mss_now,
 499                                           (flags & MSG_MORE) ? TCP_NAGLE_CORK : nonagle);
 500         }
 501 }
 502
 503 static ssize_t do_tcp_sendpages(struct sock *sk, struct page **pages, int poffset,
 504                          size_t psize, int flags)
 505 {
 506         struct tcp_sock *tp = tcp_sk(sk);
 507         int mss_now, size_goal;
 508         int err;
 509         ssize_t copied;
 510         long timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
 511
 512         /* Wait for a connection to finish. */
 513         if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT))
 514                 if ((err = sk_stream_wait_connect(sk, &timeo)) != 0)
 515                         goto out_err;
 516
 517         clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
 518
 519         mss_now = tcp_current_mss(sk, !(flags&MSG_OOB));
 520         size_goal = tp->xmit_size_goal;
 521         copied = 0;
 522
 523         err = -EPIPE;
 524         if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
 525                 goto do_error;
 526
 527         while (psize > 0) {
 528                 struct sk_buff *skb = tcp_write_queue_tail(sk);
 529                 struct page *page = pages[poffset / PAGE_SIZE];
 530                 int copy, i, can_coalesce;
 531                 int offset = poffset % PAGE_SIZE;
 532                 int size = min_t(size_t, psize, PAGE_SIZE - offset);
 533
 534                 if (!tcp_send_head(sk) || (copy = size_goal - skb->len) <= 0) {
 535 new_segment:
 536                         if (!sk_stream_memory_free(sk))
 537                                 goto wait_for_sndbuf;
 538
 539                         skb = sk_stream_alloc_pskb(sk, 0, 0,
 540                                                    sk->sk_allocation);
 541                         if (!skb)
 542                                 goto wait_for_memory;
 543
 544                         skb_entail(sk, skb);
 545                         copy = size_goal;
 546                 }
 547
 548                 if (copy > size)
 549                         copy = size;
 550
 551                 i = skb_shinfo(skb)->nr_frags;
 552                 can_coalesce = skb_can_coalesce(skb, i, page, offset);
 553                 if (!can_coalesce && i >= MAX_SKB_FRAGS) {
 554                         tcp_mark_push(tp, skb);
 555                         goto new_segment;
 556                 }
 557                 if (!sk_stream_wmem_schedule(sk, copy))
 558                         goto wait_for_memory;
 559
 560                 if (can_coalesce) {
 561                         skb_shinfo(skb)->frags[i - 1].size += copy;
 562                 } else {
 563                         get_page(page);
 564                         skb_fill_page_desc(skb, i, page, offset, copy);
 565                 }
 566
 567                 skb->len += copy;
 568                 skb->data_len += copy;
 569                 skb->truesize += copy;
 570                 sk->sk_wmem_queued += copy;
 571                 sk->sk_forward_alloc -= copy;
 572                 skb->ip_summed = CHECKSUM_PARTIAL;
 573                 tp->write_seq += copy;
 574                 TCP_SKB_CB(skb)->end_seq += copy;
 575                 skb_shinfo(skb)->gso_segs = 0;
 576
 577                 if (!copied)
 578                         TCP_SKB_CB(skb)->flags &= ~TCPCB_FLAG_PSH;
 579
 580                 copied += copy;
 581                 poffset += copy;
 582                 if (!(psize -= copy))
 583                         goto out;
 584
 585                 if (skb->len < mss_now || (flags & MSG_OOB))
 586                         continue;
 587
 588                 if (forced_push(tp)) {
 589                         tcp_mark_push(tp, skb);
 590                         __tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH);
 591                 } else if (skb == tcp_send_head(sk))
 592                         tcp_push_one(sk, mss_now);
 593                 continue;
 594
 595 wait_for_sndbuf:
 596                 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
 597 wait_for_memory:
 598                 if (copied)
 599                         tcp_push(sk, flags & ~MSG_MORE, mss_now, TCP_NAGLE_PUSH);
 600
 601                 if ((err = sk_stream_wait_memory(sk, &timeo)) != 0)
 602                         goto do_error;
 603
 604                 mss_now = tcp_current_mss(sk, !(flags&MSG_OOB));
 605                 size_goal = tp->xmit_size_goal;
 606         }
 607
 608 out:
 609         if (copied)
 610                 tcp_push(sk, flags, mss_now, tp->nonagle);
 611         return copied;
 612
 613 do_error:
 614         if (copied)
 615                 goto out;
 616 out_err:
 617         return sk_stream_error(sk, flags, err);
 618 }
 619
 620 ssize_t tcp_sendpage(struct socket *sock, struct page *page, int offset,
 621                      size_t size, int flags)
 622 {
 623         ssize_t res;
 624         struct sock *sk = sock->sk;
 625
 626         if (!(sk->sk_route_caps & NETIF_F_SG) ||
 627             !(sk->sk_route_caps & NETIF_F_ALL_CSUM))
 628                 return sock_no_sendpage(sock, page, offset, size, flags);
 629
 630         lock_sock(sk);
 631         TCP_CHECK_TIMER(sk);
 632         res = do_tcp_sendpages(sk, &page, offset, size, flags);
 633         TCP_CHECK_TIMER(sk);
 634         release_sock(sk);
 635         return res;
 636 }
 637
 638 #define TCP_PAGE(sk)    (sk->sk_sndmsg_page)
 639 #define TCP_OFF(sk)     (sk->sk_sndmsg_off)
 640
 641 static inline int select_size(struct sock *sk)
 642 {
 643         struct tcp_sock *tp = tcp_sk(sk);
 644         int tmp = tp->mss_cache;
 645
 646         if (sk->sk_route_caps & NETIF_F_SG) {
 647                 if (sk_can_gso(sk))
 648                         tmp = 0;
 649                 else {
 650                         int pgbreak = SKB_MAX_HEAD(MAX_TCP_HEADER);
 651
 652                         if (tmp >= pgbreak &&
 653                             tmp <= pgbreak + (MAX_SKB_FRAGS - 1) * PAGE_SIZE)
 654                                 tmp = pgbreak;
 655                 }
 656         }
 657
 658         return tmp;
 659 }
 660
 661 int tcp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
 662                 size_t size)
 663 {
 664         struct iovec *iov;
 665         struct tcp_sock *tp = tcp_sk(sk);
 666         struct sk_buff *skb;
 667         int iovlen, flags;
 668         int mss_now, size_goal;
 669         int err, copied;
 670         long timeo;
 671
 672         lock_sock(sk);
 673         TCP_CHECK_TIMER(sk);
 674
 675         flags = msg->msg_flags;
 676         timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
 677
 678         /* Wait for a connection to finish. */
 679         if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT))
 680                 if ((err = sk_stream_wait_connect(sk, &timeo)) != 0)
 681                         goto out_err;
 682
 683         /* This should be in poll */
 684         clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
 685
 686         mss_now = tcp_current_mss(sk, !(flags&MSG_OOB));
 687         size_goal = tp->xmit_size_goal;
 688
 689         /* Ok commence sending. */
 690         iovlen = msg->msg_iovlen;
 691         iov = msg->msg_iov;
 692         copied = 0;
 693
 694         err = -EPIPE;
 695         if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
 696                 goto do_error;
 697
 698         while (--iovlen >= 0) {
 699                 int seglen = iov->iov_len;
 700                 unsigned char __user *from = iov->iov_base;
 701
 702                 iov++;
 703
 704                 while (seglen > 0) {
 705                         int copy;
 706
 707                         skb = tcp_write_queue_tail(sk);
 708
 709                         if (!tcp_send_head(sk) ||
 710                             (copy = size_goal - skb->len) <= 0) {
 711
 712 new_segment:
 713                                 /* Allocate new segment. If the interface is SG,
 714                                  * allocate skb fitting to single page.
 715                                  */
 716                                 if (!sk_stream_memory_free(sk))
 717                                         goto wait_for_sndbuf;
 718
 719                                 skb = sk_stream_alloc_pskb(sk, select_size(sk),
 720                                                            0, sk->sk_allocation);
 721                                 if (!skb)
 722                                         goto wait_for_memory;
 723
 724                                 /*
 725                                  * Check whether we can use HW checksum.
 726                                  */
 727                                 if (sk->sk_route_caps & NETIF_F_ALL_CSUM)
 728                                         skb->ip_summed = CHECKSUM_PARTIAL;
 729
 730                                 skb_entail(sk, skb);
 731                                 copy = size_goal;
 732                         }
 733
 734                         /* Try to append data to the end of skb. */
 735                         if (copy > seglen)
 736                                 copy = seglen;
 737
 738                         /* Where to copy to? */
 739                         if (skb_tailroom(skb) > 0) {
 740                                 /* We have some space in skb head. Superb! */
 741                                 if (copy > skb_tailroom(skb))
 742                                         copy = skb_tailroom(skb);
 743                                 if ((err = skb_add_data(skb, from, copy)) != 0)
 744                                         goto do_fault;
 745                         } else {
 746                                 int merge = 0;
 747                                 int i = skb_shinfo(skb)->nr_frags;
 748                                 struct page *page = TCP_PAGE(sk);
 749                                 int off = TCP_OFF(sk);
 750
 751                                 if (skb_can_coalesce(skb, i, page, off) &&
 752                                     off != PAGE_SIZE) {
 753                                         /* We can extend the last page
 754                                          * fragment. */
 755                                         merge = 1;
 756                                 } else if (i == MAX_SKB_FRAGS ||
 757                                            (!i &&
 758                                            !(sk->sk_route_caps & NETIF_F_SG))) {
 759                                         /* Need to add new fragment and cannot
 760                                          * do this because interface is non-SG,
 761                                          * or because all the page slots are
 762                                          * busy. */
 763                                         tcp_mark_push(tp, skb);
 764                                         goto new_segment;
 765                                 } else if (page) {
 766                                         if (off == PAGE_SIZE) {
 767                                                 put_page(page);
 768                                                 TCP_PAGE(sk) = page = NULL;
 769                                                 off = 0;
 770                                         }
 771                                 } else
 772                                         off = 0;
 773
 774                                 if (copy > PAGE_SIZE - off)
 775                                         copy = PAGE_SIZE - off;
 776
 777                                 if (!sk_stream_wmem_schedule(sk, copy))
 778                                         goto wait_for_memory;
 779
 780                                 if (!page) {
 781                                         /* Allocate new cache page. */
 782                                         if (!(page = sk_stream_alloc_page(sk)))
 783                                                 goto wait_for_memory;
 784                                 }
 785
 786                                 /* Time to copy data. We are close to
 787                                  * the end! */
 788                                 err = skb_copy_to_page(sk, from, skb, page,
 789                                                        off, copy);
 790                                 if (err) {
 791                                         /* If this page was new, give it to the
 792                                          * socket so it does not get leaked.
 793                                          */
 794                                         if (!TCP_PAGE(sk)) {
 795                                                 TCP_PAGE(sk) = page;
 796                                                 TCP_OFF(sk) = 0;
 797                                         }
 798                                         goto do_error;
 799                                 }
 800
 801                                 /* Update the skb. */
 802                                 if (merge) {
 803                                         skb_shinfo(skb)->frags[i - 1].size +=
 804                                                                         copy;
 805                                 } else {
 806                                         skb_fill_page_desc(skb, i, page, off, copy);
 807                                         if (TCP_PAGE(sk)) {
 808                                                 get_page(page);
 809                                         } else if (off + copy < PAGE_SIZE) {
 810                                                 get_page(page);
 811                                                 TCP_PAGE(sk) = page;
 812                                         }
 813                                 }
 814
 815                                 TCP_OFF(sk) = off + copy;
 816                         }
 817
 818                         if (!copied)
 819                                 TCP_SKB_CB(skb)->flags &= ~TCPCB_FLAG_PSH;
 820
 821                         tp->write_seq += copy;
 822                         TCP_SKB_CB(skb)->end_seq += copy;
 823                         skb_shinfo(skb)->gso_segs = 0;
 824
 825                         from += copy;
 826                         copied += copy;
 827                         if ((seglen -= copy) == 0 && iovlen == 0)
 828                                 goto out;
 829
 830                         if (skb->len < mss_now || (flags & MSG_OOB))
 831                                 continue;
 832
 833                         if (forced_push(tp)) {
 834                                 tcp_mark_push(tp, skb);
 835                                 __tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH);
 836                         } else if (skb == tcp_send_head(sk))
 837                                 tcp_push_one(sk, mss_now);
 838                         continue;
 839
 840 wait_for_sndbuf:
 841                         set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
 842 wait_for_memory:
 843                         if (copied)
 844                                 tcp_push(sk, flags & ~MSG_MORE, mss_now, TCP_NAGLE_PUSH);
 845
 846                         if ((err = sk_stream_wait_memory(sk, &timeo)) != 0)
 847                                 goto do_error;
 848
 849                         mss_now = tcp_current_mss(sk, !(flags&MSG_OOB));
 850                         size_goal = tp->xmit_size_goal;
 851                 }
 852         }
 853
 854 out:
 855         if (copied)
 856                 tcp_push(sk, flags, mss_now, tp->nonagle);
 857         TCP_CHECK_TIMER(sk);
 858         release_sock(sk);
 859         return copied;
 860
 861 do_fault:
 862         if (!skb->len) {
 863                 tcp_unlink_write_queue(skb, sk);
 864                 /* It is the one place in all of TCP, except connection
 865                  * reset, where we can be unlinking the send_head.
 866                  */
 867                 tcp_check_send_head(sk, skb);
 868                 sk_stream_free_skb(sk, skb);
 869         }
 870
 871 do_error:
 872         if (copied)
 873                 goto out;
 874 out_err:
 875         err = sk_stream_error(sk, flags, err);
 876         TCP_CHECK_TIMER(sk);
 877         release_sock(sk);
 878         return err;
 879 }
 880
 881 /*
 882  *      Handle reading urgent data. BSD has very simple semantics for
 883  *      this, no blocking and very strange errors 8)
 884  */
 885
 886 static int tcp_recv_urg(struct sock *sk, long timeo,
 887                         struct msghdr *msg, int len, int flags,
 888                         int *addr_len)
 889 {
 890         struct tcp_sock *tp = tcp_sk(sk);
 891
 892         /* No URG data to read. */
 893         if (sock_flag(sk, SOCK_URGINLINE) || !tp->urg_data ||
 894             tp->urg_data == TCP_URG_READ)
 895                 return -EINVAL; /* Yes this is right ! */
 896
 897         if (sk->sk_state == TCP_CLOSE && !sock_flag(sk, SOCK_DONE))
 898                 return -ENOTCONN;
 899
 900         if (tp->urg_data & TCP_URG_VALID) {
 901                 int err = 0;
 902                 char c = tp->urg_data;
 903
 904                 if (!(flags & MSG_PEEK))
 905                         tp->urg_data = TCP_URG_READ;
 906
 907                 /* Read urgent data. */
 908                 msg->msg_flags |= MSG_OOB;
 909
 910                 if (len > 0) {
 911                         if (!(flags & MSG_TRUNC))
 912                                 err = memcpy_toiovec(msg->msg_iov, &c, 1);
 913                         len = 1;
 914                 } else
 915                         msg->msg_flags |= MSG_TRUNC;
 916
 917                 return err ? -EFAULT : len;
 918         }
 919
 920         if (sk->sk_state == TCP_CLOSE || (sk->sk_shutdown & RCV_SHUTDOWN))
 921                 return 0;
 922
 923         /* Fixed the recv(..., MSG_OOB) behaviour.  BSD docs and
 924          * the available implementations agree in this case:
 925          * this call should never block, independent of the
 926          * blocking state of the socket.
 927          * Mike <pall@rz.uni-karlsruhe.de>
 928          */
 929         return -EAGAIN;
 930 }
 931
 932 /* Clean up the receive buffer for full frames taken by the user,
 933  * then send an ACK if necessary.  COPIED is the number of bytes
 934  * tcp_recvmsg has given to the user so far, it speeds up the
 935  * calculation of whether or not we must ACK for the sake of
 936  * a window update.
 937  */
 938 void tcp_cleanup_rbuf(struct sock *sk, int copied)
 939 {
 940         struct tcp_sock *tp = tcp_sk(sk);
 941         int time_to_ack = 0;
 942
 943 #if TCP_DEBUG
 944         struct sk_buff *skb = skb_peek(&sk->sk_receive_queue);
 945
 946         BUG_TRAP(!skb || before(tp->copied_seq, TCP_SKB_CB(skb)->end_seq));
 947 #endif
 948
 949         if (inet_csk_ack_scheduled(sk)) {
 950                 const struct inet_connection_sock *icsk = inet_csk(sk);
 951                    /* Delayed ACKs frequently hit locked sockets during bulk
 952                     * receive. */
 953                 if (icsk->icsk_ack.blocked ||
 954                     /* Once-per-two-segments ACK was not sent by tcp_input.c */
 955                     tp->rcv_nxt - tp->rcv_wup > icsk->icsk_ack.rcv_mss ||
 956                     /*
 957                      * If this read emptied read buffer, we send ACK, if
 958                      * connection is not bidirectional, user drained
 959                      * receive buffer and there was a small segment
 960                      * in queue.
 961                      */
 962                     (copied > 0 &&
 963                      ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED2) ||
 964                       ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED) &&
 965                        !icsk->icsk_ack.pingpong)) &&
 966                       !atomic_read(&sk->sk_rmem_alloc)))
 967                         time_to_ack = 1;
 968         }
 969
 970         /* We send an ACK if we can now advertise a non-zero window
 971          * which has been raised "significantly".
 972          *
 973          * Even if window raised up to infinity, do not send window open ACK
 974          * in states, where we will not receive more. It is useless.
 975          */
 976         if (copied > 0 && !time_to_ack && !(sk->sk_shutdown & RCV_SHUTDOWN)) {
 977                 __u32 rcv_window_now = tcp_receive_window(tp);
 978
 979                 /* Optimize, __tcp_select_window() is not cheap. */
 980                 if (2*rcv_window_now <= tp->window_clamp) {
 981                         __u32 new_window = __tcp_select_window(sk);
 982
 983                         /* Send ACK now, if this read freed lots of space
 984                          * in our buffer. Certainly, new_window is new window.
 985                          * We can advertise it now, if it is not less than current one.
 986                          * "Lots" means "at least twice" here.
 987                          */
 988                         if (new_window && new_window >= 2 * rcv_window_now)
 989                                 time_to_ack = 1;
 990                 }
 991         }
 992         if (time_to_ack)
 993                 tcp_send_ack(sk);
 994 }
 995
 996 static void tcp_prequeue_process(struct sock *sk)
 997 {
 998         struct sk_buff *skb;
 999         struct tcp_sock *tp = tcp_sk(sk);
1000
1001         NET_INC_STATS_USER(LINUX_MIB_TCPPREQUEUED);
1002
1003         /* RX process wants to run with disabled BHs, though it is not
1004          * necessary */
1005         local_bh_disable();
1006         while ((skb = __skb_dequeue(&tp->ucopy.prequeue)) != NULL)
1007                 sk->sk_backlog_rcv(sk, skb);
1008         local_bh_enable();
1009
1010         /* Clear memory counter. */
1011         tp->ucopy.memory = 0;
1012 }
1013
1014 static inline struct sk_buff *tcp_recv_skb(struct sock *sk, u32 seq, u32 *off)
1015 {
1016         struct sk_buff *skb;
1017         u32 offset;
1018
1019         skb_queue_walk(&sk->sk_receive_queue, skb) {
1020                 offset = seq - TCP_SKB_CB(skb)->seq;
1021                 if (tcp_hdr(skb)->syn)
1022                         offset--;
1023                 if (offset < skb->len || tcp_hdr(skb)->fin) {
1024                         *off = offset;
1025                         return skb;
1026                 }
1027         }
1028         return NULL;
1029 }
1030
1031 /*
1032  * This routine provides an alternative to tcp_recvmsg() for routines
1033  * that would like to handle copying from skbuffs directly in 'sendfile'
1034  * fashion.
1035  * Note:
1036  *      - It is assumed that the socket was locked by the caller.
1037  *      - The routine does not block.
1038  *      - At present, there is no support for reading OOB data
1039  *        or for 'peeking' the socket using this routine
1040  *        (although both would be easy to implement).
1041  */
1042 int tcp_read_sock(struct sock *sk, read_descriptor_t *desc,
1043                   sk_read_actor_t recv_actor)
1044 {
1045         struct sk_buff *skb;
1046         struct tcp_sock *tp = tcp_sk(sk);
1047         u32 seq = tp->copied_seq;
1048         u32 offset;
1049         int copied = 0;
1050
1051         if (sk->sk_state == TCP_LISTEN)
1052                 return -ENOTCONN;
1053         while ((skb = tcp_recv_skb(sk, seq, &offset)) != NULL) {
1054                 if (offset < skb->len) {
1055                         size_t used, len;
1056
1057                         len = skb->len - offset;
1058                         /* Stop reading if we hit a patch of urgent data */
1059                         if (tp->urg_data) {
1060                                 u32 urg_offset = tp->urg_seq - seq;
1061                                 if (urg_offset < len)
1062                                         len = urg_offset;
1063                                 if (!len)
1064                                         break;
1065                         }
1066                         used = recv_actor(desc, skb, offset, len);
1067                         if (used < 0) {
1068                                 if (!copied)
1069                                         copied = used;
1070                                 break;
1071                         } else if (used <= len) {
1072                                 seq += used;
1073                                 copied += used;
1074                                 offset += used;
1075                         }
1076                         if (offset != skb->len)
1077                                 break;
1078                 }
1079                 if (tcp_hdr(skb)->fin) {
1080                         sk_eat_skb(sk, skb, 0);
1081                         ++seq;
1082                         break;
1083                 }
1084                 sk_eat_skb(sk, skb, 0);
1085                 if (!desc->count)
1086                         break;
1087         }
1088         tp->copied_seq = seq;
1089
1090         tcp_rcv_space_adjust(sk);
1091
1092         /* Clean up data we have read: This will do ACK frames. */
1093         if (copied > 0)
1094                 tcp_cleanup_rbuf(sk, copied);
1095         return copied;
1096 }
1097
1098 /*
1099  *      This routine copies from a sock struct into the user buffer.
1100  *
1101  *      Technical note: in 2.3 we work on _locked_ socket, so that
1102  *      tricks with *seq access order and skb->users are not required.
1103  *      Probably, code can be easily improved even more.
1104  */
1105
1106 int tcp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
1107                 size_t len, int nonblock, int flags, int *addr_len)
1108 {
1109         struct tcp_sock *tp = tcp_sk(sk);
1110         int copied = 0;
1111         u32 peek_seq;
1112         u32 *seq;
1113         unsigned long used;
1114         int err;
1115         int target;             /* Read at least this many bytes */
1116         long timeo;
1117         struct task_struct *user_recv = NULL;
1118         int copied_early = 0;
1119         int available = 0;
1120         struct sk_buff *skb;
1121
1122         lock_sock(sk);
1123
1124         TCP_CHECK_TIMER(sk);
1125
1126         err = -ENOTCONN;
1127         if (sk->sk_state == TCP_LISTEN)
1128                 goto out;
1129
1130         timeo = sock_rcvtimeo(sk, nonblock);
1131
1132         /* Urgent data needs to be handled specially. */
1133         if (flags & MSG_OOB)
1134                 goto recv_urg;
1135
1136         seq = &tp->copied_seq;
1137         if (flags & MSG_PEEK) {
1138                 peek_seq = tp->copied_seq;
1139                 seq = &peek_seq;
1140         }
1141
1142         target = sock_rcvlowat(sk, flags & MSG_WAITALL, len);
1143
1144 #ifdef CONFIG_NET_DMA
1145         tp->ucopy.dma_chan = NULL;
1146         preempt_disable();
1147         skb = skb_peek_tail(&sk->sk_receive_queue);
1148         if (skb)
1149                 available = TCP_SKB_CB(skb)->seq + skb->len - (*seq);
1150         if ((available < target) &&
1151             (len > sysctl_tcp_dma_copybreak) && !(flags & MSG_PEEK) &&
1152             !sysctl_tcp_low_latency && __get_cpu_var(softnet_data).net_dma) {
1153                 preempt_enable_no_resched();
1154                 tp->ucopy.pinned_list = dma_pin_iovec_pages(msg->msg_iov, len);
1155         } else
1156                 preempt_enable_no_resched();
1157 #endif
1158
1159         do {
1160                 u32 offset;
1161
1162                 /* Are we at urgent data? Stop if we have read anything or have SIGURG pending. */
1163                 if (tp->urg_data && tp->urg_seq == *seq) {
1164                         if (copied)
1165                                 break;
1166                         if (signal_pending(current)) {
1167                                 copied = timeo ? sock_intr_errno(timeo) : -EAGAIN;
1168                                 break;
1169                         }
1170                 }
1171
1172                 /* Next get a buffer. */
1173
1174                 skb = skb_peek(&sk->sk_receive_queue);
1175                 do {
1176                         if (!skb)
1177                                 break;
1178
1179                         /* Now that we have two receive queues this
1180                          * shouldn't happen.
1181                          */
1182                         if (before(*seq, TCP_SKB_CB(skb)->seq)) {
1183                                 printk(KERN_INFO "recvmsg bug: copied %X "
1184                                        "seq %X\n", *seq, TCP_SKB_CB(skb)->seq);
1185                                 break;
1186                         }
1187                         offset = *seq - TCP_SKB_CB(skb)->seq;
1188                         if (tcp_hdr(skb)->syn)
1189                                 offset--;
1190                         if (offset < skb->len)
1191                                 goto found_ok_skb;
1192                         if (tcp_hdr(skb)->fin)
1193                                 goto found_fin_ok;
1194                         BUG_TRAP(flags & MSG_PEEK);
1195                         skb = skb->next;
1196                 } while (skb != (struct sk_buff *)&sk->sk_receive_queue);
1197
1198                 /* Well, if we have backlog, try to process it now yet. */
1199
1200                 if (copied >= target && !sk->sk_backlog.tail)
1201                         break;
1202
1203                 if (copied) {
1204                         if (sk->sk_err ||
1205                             sk->sk_state == TCP_CLOSE ||
1206                             (sk->sk_shutdown & RCV_SHUTDOWN) ||
1207                             !timeo ||
1208                             signal_pending(current) ||
1209                             (flags & MSG_PEEK))
1210                                 break;
1211                 } else {
1212                         if (sock_flag(sk, SOCK_DONE))
1213                                 break;
1214
1215                         if (sk->sk_err) {
1216                                 copied = sock_error(sk);
1217                                 break;
1218                         }
1219
1220                         if (sk->sk_shutdown & RCV_SHUTDOWN)
1221                                 break;
1222
1223                         if (sk->sk_state == TCP_CLOSE) {
1224                                 if (!sock_flag(sk, SOCK_DONE)) {
1225                                         /* This occurs when user tries to read
1226                                          * from never connected socket.
1227                                          */
1228                                         copied = -ENOTCONN;
1229                                         break;
1230                                 }
1231                                 break;
1232                         }
1233
1234                         if (!timeo) {
1235                                 copied = -EAGAIN;
1236                                 break;
1237                         }
1238
1239                         if (signal_pending(current)) {
1240                                 copied = sock_intr_errno(timeo);
1241                                 break;
1242                         }
1243                 }
1244
1245                 tcp_cleanup_rbuf(sk, copied);
1246
1247                 if (!sysctl_tcp_low_latency && tp->ucopy.task == user_recv) {
1248                         /* Install new reader */
1249                         if (!user_recv && !(flags & (MSG_TRUNC | MSG_PEEK))) {
1250                                 user_recv = current;
1251                                 tp->ucopy.task = user_recv;
1252                                 tp->ucopy.iov = msg->msg_iov;
1253                         }
1254
1255                         tp->ucopy.len = len;
1256
1257                         BUG_TRAP(tp->copied_seq == tp->rcv_nxt ||
1258                                  (flags & (MSG_PEEK | MSG_TRUNC)));
1259
1260                         /* Ugly... If prequeue is not empty, we have to
1261                          * process it before releasing socket, otherwise
1262                          * order will be broken at second iteration.
1263                          * More elegant solution is required!!!
1264                          *
1265                          * Look: we have the following (pseudo)queues:
1266                          *
1267                          * 1. packets in flight
1268                          * 2. backlog
1269                          * 3. prequeue
1270                          * 4. receive_queue
1271                          *
1272                          * Each queue can be processed only if the next ones
1273                          * are empty. At this point we have empty receive_queue.
1274                          * But prequeue _can_ be not empty after 2nd iteration,
1275                          * when we jumped to start of loop because backlog
1276                          * processing added something to receive_queue.
1277                          * We cannot release_sock(), because backlog contains
1278                          * packets arrived _after_ prequeued ones.
1279                          *
1280                          * Shortly, algorithm is clear --- to process all
1281                          * the queues in order. We could make it more directly,
1282                          * requeueing packets from backlog to prequeue, if
1283                          * is not empty. It is more elegant, but eats cycles,
1284                          * unfortunately.
1285                          */
1286                         if (!skb_queue_empty(&tp->ucopy.prequeue))
1287                                 goto do_prequeue;
1288
1289                         /* __ Set realtime policy in scheduler __ */
1290                 }
1291
1292                 if (copied >= target) {
1293                         /* Do not sleep, just process backlog. */
1294                         release_sock(sk);
1295                         lock_sock(sk);
1296                 } else
1297                         sk_wait_data(sk, &timeo);
1298
1299 #ifdef CONFIG_NET_DMA
1300                 tp->ucopy.wakeup = 0;
1301 #endif
1302
1303                 if (user_recv) {
1304                         int chunk;
1305
1306                         /* __ Restore normal policy in scheduler __ */
1307
1308                         if ((chunk = len - tp->ucopy.len) != 0) {
1309                                 NET_ADD_STATS_USER(LINUX_MIB_TCPDIRECTCOPYFROMBACKLOG, chunk);
1310                                 len -= chunk;
1311                                 copied += chunk;
1312                         }
1313
1314                         if (tp->rcv_nxt == tp->copied_seq &&
1315                             !skb_queue_empty(&tp->ucopy.prequeue)) {
1316 do_prequeue:
1317                                 tcp_prequeue_process(sk);
1318
1319                                 if ((chunk = len - tp->ucopy.len) != 0) {
1320                                         NET_ADD_STATS_USER(LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
1321                                         len -= chunk;
1322                                         copied += chunk;
1323                                 }
1324                         }
1325                 }
1326                 if ((flags & MSG_PEEK) && peek_seq != tp->copied_seq) {
1327                         if (net_ratelimit())
1328                                 printk(KERN_DEBUG "TCP(%s:%d): Application bug, race in MSG_PEEK.\n",
1329                                        current->comm, current->pid);
1330                         peek_seq = tp->copied_seq;
1331                 }
1332                 continue;
1333
1334         found_ok_skb:
1335                 /* Ok so how much can we use? */
1336                 used = skb->len - offset;
1337                 if (len < used)
1338                         used = len;
1339
1340                 /* Do we have urgent data here? */
1341                 if (tp->urg_data) {
1342                         u32 urg_offset = tp->urg_seq - *seq;
1343                         if (urg_offset < used) {
1344                                 if (!urg_offset) {
1345                                         if (!sock_flag(sk, SOCK_URGINLINE)) {
1346                                                 ++*seq;
1347                                                 offset++;
1348                                                 used--;
1349                                                 if (!used)
1350                                                         goto skip_copy;
1351                                         }
1352                                 } else
1353                                         used = urg_offset;
1354                         }
1355                 }
1356
1357                 if (!(flags & MSG_TRUNC)) {
1358 #ifdef CONFIG_NET_DMA
1359                         if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list)
1360                                 tp->ucopy.dma_chan = get_softnet_dma();
1361
1362                         if (tp->ucopy.dma_chan) {
1363                                 tp->ucopy.dma_cookie = dma_skb_copy_datagram_iovec(
1364                                         tp->ucopy.dma_chan, skb, offset,
1365                                         msg->msg_iov, used,
1366                                         tp->ucopy.pinned_list);
1367
1368                                 if (tp->ucopy.dma_cookie < 0) {
1369
1370                                         printk(KERN_ALERT "dma_cookie < 0\n");
1371
1372                                         /* Exception. Bailout! */
1373                                         if (!copied)
1374                                                 copied = -EFAULT;
1375                                         break;
1376                                 }
1377                                 if ((offset + used) == skb->len)
1378                                         copied_early = 1;
1379
1380                         } else
1381 #endif
1382                         {
1383                                 err = skb_copy_datagram_iovec(skb, offset,
1384                                                 msg->msg_iov, used);
1385                                 if (err) {
1386                                         /* Exception. Bailout! */
1387                                         if (!copied)
1388                                                 copied = -EFAULT;
1389                                         break;
1390                                 }
1391                         }
1392                 }
1393
1394                 *seq += used;
1395                 copied += used;
1396                 len -= used;
1397
1398                 tcp_rcv_space_adjust(sk);
1399
1400 skip_copy:
1401                 if (tp->urg_data && after(tp->copied_seq, tp->urg_seq)) {
1402                         tp->urg_data = 0;
1403                         tcp_fast_path_check(sk);
1404                 }
1405                 if (used + offset < skb->len)
1406                         continue;
1407
1408                 if (tcp_hdr(skb)->fin)
1409                         goto found_fin_ok;
1410                 if (!(flags & MSG_PEEK)) {
1411                         sk_eat_skb(sk, skb, copied_early);
1412                         copied_early = 0;
1413                 }
1414                 continue;
1415
1416         found_fin_ok:
1417                 /* Process the FIN. */
1418                 ++*seq;
1419                 if (!(flags & MSG_PEEK)) {
1420                         sk_eat_skb(sk, skb, copied_early);
1421                         copied_early = 0;
1422                 }
1423                 break;
1424         } while (len > 0);
1425
1426         if (user_recv) {
1427                 if (!skb_queue_empty(&tp->ucopy.prequeue)) {
1428                         int chunk;
1429
1430                         tp->ucopy.len = copied > 0 ? len : 0;
1431
1432                         tcp_prequeue_process(sk);
1433
1434                         if (copied > 0 && (chunk = len - tp->ucopy.len) != 0) {
1435                                 NET_ADD_STATS_USER(LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
1436                                 len -= chunk;
1437                                 copied += chunk;
1438                         }
1439                 }
1440
1441                 tp->ucopy.task = NULL;
1442                 tp->ucopy.len = 0;
1443         }
1444
1445 #ifdef CONFIG_NET_DMA
1446         if (tp->ucopy.dma_chan) {
1447                 dma_cookie_t done, used;
1448
1449                 dma_async_memcpy_issue_pending(tp->ucopy.dma_chan);
1450
1451                 while (dma_async_memcpy_complete(tp->ucopy.dma_chan,
1452                                                  tp->ucopy.dma_cookie, &done,
1453                                                  &used) == DMA_IN_PROGRESS) {
1454                         /* do partial cleanup of sk_async_wait_queue */
1455                         while ((skb = skb_peek(&sk->sk_async_wait_queue)) &&
1456                                (dma_async_is_complete(skb->dma_cookie, done,
1457                                                       used) == DMA_SUCCESS)) {
1458                                 __skb_dequeue(&sk->sk_async_wait_queue);
1459                                 kfree_skb(skb);
1460                         }
1461                 }
1462
1463                 /* Safe to free early-copied skbs now */
1464                 __skb_queue_purge(&sk->sk_async_wait_queue);
1465                 dma_chan_put(tp->ucopy.dma_chan);
1466                 tp->ucopy.dma_chan = NULL;
1467         }
1468         if (tp->ucopy.pinned_list) {
1469                 dma_unpin_iovec_pages(tp->ucopy.pinned_list);
1470                 tp->ucopy.pinned_list = NULL;
1471         }
1472 #endif
1473
1474         /* According to UNIX98, msg_name/msg_namelen are ignored
1475          * on connected socket. I was just happy when found this 8) --ANK
1476          */
1477
1478         /* Clean up data we have read: This will do ACK frames. */
1479         tcp_cleanup_rbuf(sk, copied);
1480
1481         TCP_CHECK_TIMER(sk);
1482         release_sock(sk);
1483         return copied;
1484
1485 out:
1486         TCP_CHECK_TIMER(sk);
1487         release_sock(sk);
1488         return err;
1489
1490 recv_urg:
1491         err = tcp_recv_urg(sk, timeo, msg, len, flags, addr_len);
1492         goto out;
1493 }
1494
1495 /*
1496  *      State processing on a close. This implements the state shift for
1497  *      sending our FIN frame. Note that we only send a FIN for some
1498  *      states. A shutdown() may have already sent the FIN, or we may be
1499  *      closed.
1500  */
1501
1502 static const unsigned char new_state[16] = {
1503   /* current state:        new state:      action:      */
1504   /* (Invalid)          */ TCP_CLOSE,
1505   /* TCP_ESTABLISHED    */ TCP_FIN_WAIT1 | TCP_ACTION_FIN,
1506   /* TCP_SYN_SENT       */ TCP_CLOSE,
1507   /* TCP_SYN_RECV       */ TCP_FIN_WAIT1 | TCP_ACTION_FIN,
1508   /* TCP_FIN_WAIT1      */ TCP_FIN_WAIT1,
1509   /* TCP_FIN_WAIT2      */ TCP_FIN_WAIT2,
1510   /* TCP_TIME_WAIT      */ TCP_CLOSE,
1511   /* TCP_CLOSE          */ TCP_CLOSE,
1512   /* TCP_CLOSE_WAIT     */ TCP_LAST_ACK  | TCP_ACTION_FIN,
1513   /* TCP_LAST_ACK       */ TCP_LAST_ACK,
1514   /* TCP_LISTEN         */ TCP_CLOSE,
1515   /* TCP_CLOSING        */ TCP_CLOSING,
1516 };
1517
1518 static int tcp_close_state(struct sock *sk)
1519 {
1520         int next = (int)new_state[sk->sk_state];
1521         int ns = next & TCP_STATE_MASK;
1522
1523         tcp_set_state(sk, ns);
1524
1525         return next & TCP_ACTION_FIN;
1526 }
1527
1528 /*
1529  *      Shutdown the sending side of a connection. Much like close except
1530  *      that we don't receive shut down or set_sock_flag(sk, SOCK_DEAD).
1531  */
1532
1533 void tcp_shutdown(struct sock *sk, int how)
1534 {
1535         /*      We need to grab some memory, and put together a FIN,
1536          *      and then put it into the queue to be sent.
1537          *              Tim MacKenzie(tym@dibbler.cs.monash.edu.au) 4 Dec '92.
1538          */
1539         if (!(how & SEND_SHUTDOWN))
1540                 return;
1541
1542         /* If we've already sent a FIN, or it's a closed state, skip this. */
1543         if ((1 << sk->sk_state) &
1544             (TCPF_ESTABLISHED | TCPF_SYN_SENT |
1545              TCPF_SYN_RECV | TCPF_CLOSE_WAIT)) {
1546                 /* Clear out any half completed packets.  FIN if needed. */
1547                 if (tcp_close_state(sk))
1548                         tcp_send_fin(sk);
1549         }
1550 }
1551
1552 void tcp_close(struct sock *sk, long timeout)
1553 {
1554         struct sk_buff *skb;
1555         int data_was_unread = 0;
1556         int state;
1557
1558         lock_sock(sk);
1559         sk->sk_shutdown = SHUTDOWN_MASK;
1560
1561         if (sk->sk_state == TCP_LISTEN) {
1562                 tcp_set_state(sk, TCP_CLOSE);
1563
1564                 /* Special case. */
1565                 inet_csk_listen_stop(sk);
1566
1567                 goto adjudge_to_death;
1568         }
1569
1570         /*  We need to flush the recv. buffs.  We do this only on the
1571          *  descriptor close, not protocol-sourced closes, because the
1572          *  reader process may not have drained the data yet!
1573          */
1574         while ((skb = __skb_dequeue(&sk->sk_receive_queue)) != NULL) {
1575                 u32 len = TCP_SKB_CB(skb)->end_seq - TCP_SKB_CB(skb)->seq -
1576                           tcp_hdr(skb)->fin;
1577                 data_was_unread += len;
1578                 __kfree_skb(skb);
1579         }
1580
1581         sk_stream_mem_reclaim(sk);
1582
1583         /* As outlined in RFC 2525, section 2.17, we send a RST here because
1584          * data was lost. To witness the awful effects of the old behavior of
1585          * always doing a FIN, run an older 2.1.x kernel or 2.0.x, start a bulk
1586          * GET in an FTP client, suspend the process, wait for the client to
1587          * advertise a zero window, then kill -9 the FTP client, wheee...
1588          * Note: timeout is always zero in such a case.
1589          */
1590         if (data_was_unread) {
1591                 /* Unread data was tossed, zap the connection. */
1592                 NET_INC_STATS_USER(LINUX_MIB_TCPABORTONCLOSE);
1593                 tcp_set_state(sk, TCP_CLOSE);
1594                 tcp_send_active_reset(sk, GFP_KERNEL);
1595         } else if (sock_flag(sk, SOCK_LINGER) && !sk->sk_lingertime) {
1596                 /* Check zero linger _after_ checking for unread data. */
1597                 sk->sk_prot->disconnect(sk, 0);
1598                 NET_INC_STATS_USER(LINUX_MIB_TCPABORTONDATA);
1599         } else if (tcp_close_state(sk)) {
1600                 /* We FIN if the application ate all the data before
1601                  * zapping the connection.
1602                  */
1603
1604                 /* RED-PEN. Formally speaking, we have broken TCP state
1605                  * machine. State transitions:
1606                  *
1607                  * TCP_ESTABLISHED -> TCP_FIN_WAIT1
1608                  * TCP_SYN_RECV -> TCP_FIN_WAIT1 (forget it, it's impossible)
1609                  * TCP_CLOSE_WAIT -> TCP_LAST_ACK
1610                  *
1611                  * are legal only when FIN has been sent (i.e. in window),
1612                  * rather than queued out of window. Purists blame.
1613                  *
1614                  * F.e. "RFC state" is ESTABLISHED,
1615                  * if Linux state is FIN-WAIT-1, but FIN is still not sent.
1616                  *
1617                  * The visible declinations are that sometimes
1618                  * we enter time-wait state, when it is not required really
1619                  * (harmless), do not send active resets, when they are
1620                  * required by specs (TCP_ESTABLISHED, TCP_CLOSE_WAIT, when
1621                  * they look as CLOSING or LAST_ACK for Linux)
1622                  * Probably, I missed some more holelets.
1623                  *                                              --ANK
1624                  */
1625                 tcp_send_fin(sk);
1626         }
1627
1628         sk_stream_wait_close(sk, timeout);
1629
1630 adjudge_to_death:
1631         state = sk->sk_state;
1632         sock_hold(sk);
1633         sock_orphan(sk);
1634         atomic_inc(sk->sk_prot->orphan_count);
1635
1636         /* It is the last release_sock in its life. It will remove backlog. */
1637         release_sock(sk);
1638
1639
1640         /* Now socket is owned by kernel and we acquire BH lock
1641            to finish close. No need to check for user refs.
1642          */
1643         local_bh_disable();
1644         bh_lock_sock(sk);
1645         BUG_TRAP(!sock_owned_by_user(sk));
1646
1647         /* Have we already been destroyed by a softirq or backlog? */
1648         if (state != TCP_CLOSE && sk->sk_state == TCP_CLOSE)
1649                 goto out;
1650
1651         /*      This is a (useful) BSD violating of the RFC. There is a
1652          *      problem with TCP as specified in that the other end could
1653          *      keep a socket open forever with no application left this end.
1654          *      We use a 3 minute timeout (about the same as BSD) then kill
1655          *      our end. If they send after that then tough - BUT: long enough
1656          *      that we won't make the old 4*rto = almost no time - whoops
1657          *      reset mistake.
1658          *
1659          *      Nope, it was not mistake. It is really desired behaviour
1660          *      f.e. on http servers, when such sockets are useless, but
1661          *      consume significant resources. Let's do it with special
1662          *      linger2 option.                                 --ANK
1663          */
1664
1665         if (sk->sk_state == TCP_FIN_WAIT2) {
1666                 struct tcp_sock *tp = tcp_sk(sk);
1667                 if (tp->linger2 < 0) {
1668                         tcp_set_state(sk, TCP_CLOSE);
1669                         tcp_send_active_reset(sk, GFP_ATOMIC);
1670                         NET_INC_STATS_BH(LINUX_MIB_TCPABORTONLINGER);
1671                 } else {
1672                         const int tmo = tcp_fin_time(sk);
1673
1674                         if (tmo > TCP_TIMEWAIT_LEN) {
1675                                 inet_csk_reset_keepalive_timer(sk,
1676                                                 tmo - TCP_TIMEWAIT_LEN);
1677                         } else {
1678                                 tcp_time_wait(sk, TCP_FIN_WAIT2, tmo);
1679                                 goto out;
1680                         }
1681                 }
1682         }
1683         if (sk->sk_state != TCP_CLOSE) {
1684                 sk_stream_mem_reclaim(sk);
1685                 if (tcp_too_many_orphans(sk,
1686                                 atomic_read(sk->sk_prot->orphan_count))) {
1687                         if (net_ratelimit())
1688                                 printk(KERN_INFO "TCP: too many of orphaned "
1689                                        "sockets\n");
1690                         tcp_set_state(sk, TCP_CLOSE);
1691                         tcp_send_active_reset(sk, GFP_ATOMIC);
1692                         NET_INC_STATS_BH(LINUX_MIB_TCPABORTONMEMORY);
1693                 }
1694         }
1695
1696         if (sk->sk_state == TCP_CLOSE)
1697                 inet_csk_destroy_sock(sk);
1698         /* Otherwise, socket is reprieved until protocol close. */
1699
1700 out:
1701         bh_unlock_sock(sk);
1702         local_bh_enable();
1703         sock_put(sk);
1704 }
1705
1706 /* These states need RST on ABORT according to RFC793 */
1707
1708 static inline int tcp_need_reset(int state)
1709 {
1710         return (1 << state) &
1711                (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT | TCPF_FIN_WAIT1 |
1712                 TCPF_FIN_WAIT2 | TCPF_SYN_RECV);
1713 }
1714
1715 int tcp_disconnect(struct sock *sk, int flags)
1716 {
1717         struct inet_sock *inet = inet_sk(sk);
1718         struct inet_connection_sock *icsk = inet_csk(sk);
1719         struct tcp_sock *tp = tcp_sk(sk);
1720         int err = 0;
1721         int old_state = sk->sk_state;
1722
1723         if (old_state != TCP_CLOSE)
1724                 tcp_set_state(sk, TCP_CLOSE);
1725
1726         /* ABORT function of RFC793 */
1727         if (old_state == TCP_LISTEN) {
1728                 inet_csk_listen_stop(sk);
1729         } else if (tcp_need_reset(old_state) ||
1730                    (tp->snd_nxt != tp->write_seq &&
1731                     (1 << old_state) & (TCPF_CLOSING | TCPF_LAST_ACK))) {
1732                 /* The last check adjusts for discrepancy of Linux wrt. RFC
1733                  * states
1734                  */
1735                 tcp_send_active_reset(sk, gfp_any());
1736                 sk->sk_err = ECONNRESET;
1737         } else if (old_state == TCP_SYN_SENT)
1738                 sk->sk_err = ECONNRESET;
1739
1740         tcp_clear_xmit_timers(sk);
1741         __skb_queue_purge(&sk->sk_receive_queue);
1742         tcp_write_queue_purge(sk);
1743         __skb_queue_purge(&tp->out_of_order_queue);
1744 #ifdef CONFIG_NET_DMA
1745         __skb_queue_purge(&sk->sk_async_wait_queue);
1746 #endif
1747
1748         inet->dport = 0;
1749
1750         if (!(sk->sk_userlocks & SOCK_BINDADDR_LOCK))
1751                 inet_reset_saddr(sk);
1752
1753         sk->sk_shutdown = 0;
1754         sock_reset_flag(sk, SOCK_DONE);
1755         tp->srtt = 0;
1756         if ((tp->write_seq += tp->max_window + 2) == 0)
1757                 tp->write_seq = 1;
1758         icsk->icsk_backoff = 0;
1759         tp->snd_cwnd = 2;
1760         icsk->icsk_probes_out = 0;
1761         tp->packets_out = 0;
1762         tp->snd_ssthresh = 0x7fffffff;
1763         tp->snd_cwnd_cnt = 0;
1764         tp->bytes_acked = 0;
1765         tcp_set_ca_state(sk, TCP_CA_Open);
1766         tcp_clear_retrans(tp);
1767         inet_csk_delack_init(sk);
1768         tcp_init_send_head(sk);
1769         memset(&tp->rx_opt, 0, sizeof(tp->rx_opt));
1770         __sk_dst_reset(sk);
1771
1772         BUG_TRAP(!inet->num || icsk->icsk_bind_hash);
1773
1774         sk->sk_error_report(sk);
1775         return err;
1776 }
1777
1778 /*
1779  *      Socket option code for TCP.
1780  */
1781 static int do_tcp_setsockopt(struct sock *sk, int level,
1782                 int optname, char __user *optval, int optlen)
1783 {
1784         struct tcp_sock *tp = tcp_sk(sk);
1785         struct inet_connection_sock *icsk = inet_csk(sk);
1786         int val;
1787         int err = 0;
1788
1789         /* This is a string value all the others are int's */
1790         if (optname == TCP_CONGESTION) {
1791                 char name[TCP_CA_NAME_MAX];
1792
1793                 if (optlen < 1)
1794                         return -EINVAL;
1795
1796                 val = strncpy_from_user(name, optval,
1797                                         min(TCP_CA_NAME_MAX-1, optlen));
1798                 if (val < 0)
1799                         return -EFAULT;
1800                 name[val] = 0;
1801
1802                 lock_sock(sk);
1803                 err = tcp_set_congestion_control(sk, name);
1804                 release_sock(sk);
1805                 return err;
1806         }
1807
1808         if (optlen < sizeof(int))
1809                 return -EINVAL;
1810
1811         if (get_user(val, (int __user *)optval))
1812                 return -EFAULT;
1813
1814         lock_sock(sk);
1815
1816         switch (optname) {
1817         case TCP_MAXSEG:
1818                 /* Values greater than interface MTU won't take effect. However
1819                  * at the point when this call is done we typically don't yet
1820                  * know which interface is going to be used */
1821                 if (val < 8 || val > MAX_TCP_WINDOW) {
1822                         err = -EINVAL;
1823                         break;
1824                 }
1825                 tp->rx_opt.user_mss = val;
1826                 break;
1827
1828         case TCP_NODELAY:
1829                 if (val) {
1830                         /* TCP_NODELAY is weaker than TCP_CORK, so that
1831                          * this option on corked socket is remembered, but
1832                          * it is not activated until cork is cleared.
1833                          *
1834                          * However, when TCP_NODELAY is set we make
1835                          * an explicit push, which overrides even TCP_CORK
1836                          * for currently queued segments.
1837                          */
1838                         tp->nonagle |= TCP_NAGLE_OFF|TCP_NAGLE_PUSH;
1839                         tcp_push_pending_frames(sk);
1840                 } else {
1841                         tp->nonagle &= ~TCP_NAGLE_OFF;
1842                 }
1843                 break;
1844
1845         case TCP_CORK:
1846                 /* When set indicates to always queue non-full frames.
1847                  * Later the user clears this option and we transmit
1848                  * any pending partial frames in the queue.  This is
1849                  * meant to be used alongside sendfile() to get properly
1850                  * filled frames when the user (for example) must write
1851                  * out headers with a write() call first and then use
1852                  * sendfile to send out the data parts.
1853                  *
1854                  * TCP_CORK can be set together with TCP_NODELAY and it is
1855                  * stronger than TCP_NODELAY.
1856                  */
1857                 if (val) {
1858                         tp->nonagle |= TCP_NAGLE_CORK;
1859                 } else {
1860                         tp->nonagle &= ~TCP_NAGLE_CORK;
1861                         if (tp->nonagle&TCP_NAGLE_OFF)
1862                                 tp->nonagle |= TCP_NAGLE_PUSH;
1863                         tcp_push_pending_frames(sk);
1864                 }
1865                 break;
1866
1867         case TCP_KEEPIDLE:
1868                 if (val < 1 || val > MAX_TCP_KEEPIDLE)
1869                         err = -EINVAL;
1870                 else {
1871                         tp->keepalive_time = val * HZ;
1872                         if (sock_flag(sk, SOCK_KEEPOPEN) &&
1873                             !((1 << sk->sk_state) &
1874                               (TCPF_CLOSE | TCPF_LISTEN))) {
1875                                 __u32 elapsed = tcp_time_stamp - tp->rcv_tstamp;
1876                                 if (tp->keepalive_time > elapsed)
1877                                         elapsed = tp->keepalive_time - elapsed;
1878                                 else
1879                                         elapsed = 0;
1880                                 inet_csk_reset_keepalive_timer(sk, elapsed);
1881                         }
1882                 }
1883                 break;
1884         case TCP_KEEPINTVL:
1885                 if (val < 1 || val > MAX_TCP_KEEPINTVL)
1886                         err = -EINVAL;
1887                 else
1888                         tp->keepalive_intvl = val * HZ;
1889                 break;
1890         case TCP_KEEPCNT:
1891                 if (val < 1 || val > MAX_TCP_KEEPCNT)
1892                         err = -EINVAL;
1893                 else
1894                         tp->keepalive_probes = val;
1895                 break;
1896         case TCP_SYNCNT:
1897                 if (val < 1 || val > MAX_TCP_SYNCNT)
1898                         err = -EINVAL;
1899                 else
1900                         icsk->icsk_syn_retries = val;
1901                 break;
1902
1903         case TCP_LINGER2:
1904                 if (val < 0)
1905                         tp->linger2 = -1;
1906                 else if (val > sysctl_tcp_fin_timeout / HZ)
1907                         tp->linger2 = 0;
1908                 else
1909                         tp->linger2 = val * HZ;
1910                 break;
1911
1912         case TCP_DEFER_ACCEPT:
1913                 icsk->icsk_accept_queue.rskq_defer_accept = 0;
1914                 if (val > 0) {
1915                         /* Translate value in seconds to number of
1916                          * retransmits */
1917                         while (icsk->icsk_accept_queue.rskq_defer_accept < 32 &&
1918                                val > ((TCP_TIMEOUT_INIT / HZ) <<
1919                                        icsk->icsk_accept_queue.rskq_defer_accept))
1920                                 icsk->icsk_accept_queue.rskq_defer_accept++;
1921                         icsk->icsk_accept_queue.rskq_defer_accept++;
1922                 }
1923                 break;
1924
1925         case TCP_WINDOW_CLAMP:
1926                 if (!val) {
1927                         if (sk->sk_state != TCP_CLOSE) {
1928                                 err = -EINVAL;
1929                                 break;
1930                         }
1931                         tp->window_clamp = 0;
1932                 } else
1933                         tp->window_clamp = val < SOCK_MIN_RCVBUF / 2 ?
1934                                                 SOCK_MIN_RCVBUF / 2 : val;
1935                 break;
1936
1937         case TCP_QUICKACK:
1938                 if (!val) {
1939                         icsk->icsk_ack.pingpong = 1;
1940                 } else {
1941                         icsk->icsk_ack.pingpong = 0;
1942                         if ((1 << sk->sk_state) &
1943                             (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT) &&
1944                             inet_csk_ack_scheduled(sk)) {
1945                                 icsk->icsk_ack.pending |= ICSK_ACK_PUSHED;
1946                                 tcp_cleanup_rbuf(sk, 1);
1947                                 if (!(val & 1))
1948                                         icsk->icsk_ack.pingpong = 1;
1949                         }
1950                 }
1951                 break;
1952
1953 #ifdef CONFIG_TCP_MD5SIG
1954         case TCP_MD5SIG:
1955                 /* Read the IP->Key mappings from userspace */
1956                 err = tp->af_specific->md5_parse(sk, optval, optlen);
1957                 break;
1958 #endif
1959
1960         default:
1961                 err = -ENOPROTOOPT;
1962                 break;
1963         }
1964
1965         release_sock(sk);
1966         return err;
1967 }
1968
1969 int tcp_setsockopt(struct sock *sk, int level, int optname, char __user *optval,
1970                    int optlen)
1971 {
1972         struct inet_connection_sock *icsk = inet_csk(sk);
1973
1974         if (level != SOL_TCP)
1975                 return icsk->icsk_af_ops->setsockopt(sk, level, optname,
1976                                                      optval, optlen);
1977         return do_tcp_setsockopt(sk, level, optname, optval, optlen);
1978 }
1979
1980 #ifdef CONFIG_COMPAT
1981 int compat_tcp_setsockopt(struct sock *sk, int level, int optname,
1982                           char __user *optval, int optlen)
1983 {
1984         if (level != SOL_TCP)
1985                 return inet_csk_compat_setsockopt(sk, level, optname,
1986                                                   optval, optlen);
1987         return do_tcp_setsockopt(sk, level, optname, optval, optlen);
1988 }
1989
1990 EXPORT_SYMBOL(compat_tcp_setsockopt);
1991 #endif
1992
1993 /* Return information about state of tcp endpoint in API format. */
1994 void tcp_get_info(struct sock *sk, struct tcp_info *info)
1995 {
1996         struct tcp_sock *tp = tcp_sk(sk);
1997         const struct inet_connection_sock *icsk = inet_csk(sk);
1998         u32 now = tcp_time_stamp;
1999
2000         memset(info, 0, sizeof(*info));
2001
2002         info->tcpi_state = sk->sk_state;
2003         info->tcpi_ca_state = icsk->icsk_ca_state;
2004         info->tcpi_retransmits = icsk->icsk_retransmits;
2005         info->tcpi_probes = icsk->icsk_probes_out;
2006         info->tcpi_backoff = icsk->icsk_backoff;
2007
2008         if (tp->rx_opt.tstamp_ok)
2009                 info->tcpi_options |= TCPI_OPT_TIMESTAMPS;
2010         if (tp->rx_opt.sack_ok)
2011                 info->tcpi_options |= TCPI_OPT_SACK;
2012         if (tp->rx_opt.wscale_ok) {
2013                 info->tcpi_options |= TCPI_OPT_WSCALE;
2014                 info->tcpi_snd_wscale = tp->rx_opt.snd_wscale;
2015                 info->tcpi_rcv_wscale = tp->rx_opt.rcv_wscale;
2016         }
2017
2018         if (tp->ecn_flags&TCP_ECN_OK)
2019                 info->tcpi_options |= TCPI_OPT_ECN;
2020
2021         info->tcpi_rto = jiffies_to_usecs(icsk->icsk_rto);
2022         info->tcpi_ato = jiffies_to_usecs(icsk->icsk_ack.ato);
2023         info->tcpi_snd_mss = tp->mss_cache;
2024         info->tcpi_rcv_mss = icsk->icsk_ack.rcv_mss;
2025
2026         info->tcpi_unacked = tp->packets_out;
2027         info->tcpi_sacked = tp->sacked_out;
2028         info->tcpi_lost = tp->lost_out;
2029         info->tcpi_retrans = tp->retrans_out;
2030         info->tcpi_fackets = tp->fackets_out;
2031
2032         info->tcpi_last_data_sent = jiffies_to_msecs(now - tp->lsndtime);
2033         info->tcpi_last_data_recv = jiffies_to_msecs(now - icsk->icsk_ack.lrcvtime);
2034         info->tcpi_last_ack_recv = jiffies_to_msecs(now - tp->rcv_tstamp);
2035
2036         info->tcpi_pmtu = icsk->icsk_pmtu_cookie;
2037         info->tcpi_rcv_ssthresh = tp->rcv_ssthresh;
2038         info->tcpi_rtt = jiffies_to_usecs(tp->srtt)>>3;
2039         info->tcpi_rttvar = jiffies_to_usecs(tp->mdev)>>2;
2040         info->tcpi_snd_ssthresh = tp->snd_ssthresh;
2041         info->tcpi_snd_cwnd = tp->snd_cwnd;
2042         info->tcpi_advmss = tp->advmss;
2043         info->tcpi_reordering = tp->reordering;
2044
2045         info->tcpi_rcv_rtt = jiffies_to_usecs(tp->rcv_rtt_est.rtt)>>3;
2046         info->tcpi_rcv_space = tp->rcvq_space.space;
2047
2048         info->tcpi_total_retrans = tp->total_retrans;
2049 }
2050
2051 EXPORT_SYMBOL_GPL(tcp_get_info);
2052
2053 static int do_tcp_getsockopt(struct sock *sk, int level,
2054                 int optname, char __user *optval, int __user *optlen)
2055 {
2056         struct inet_connection_sock *icsk = inet_csk(sk);
2057         struct tcp_sock *tp = tcp_sk(sk);
2058         int val, len;
2059
2060         if (get_user(len, optlen))
2061                 return -EFAULT;
2062
2063         len = min_t(unsigned int, len, sizeof(int));
2064
2065         if (len < 0)
2066                 return -EINVAL;
2067
2068         switch (optname) {
2069         case TCP_MAXSEG:
2070                 val = tp->mss_cache;
2071                 if (!val && ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN)))
2072                         val = tp->rx_opt.user_mss;
2073                 break;
2074         case TCP_NODELAY:
2075                 val = !!(tp->nonagle&TCP_NAGLE_OFF);
2076                 break;
2077         case TCP_CORK:
2078                 val = !!(tp->nonagle&TCP_NAGLE_CORK);
2079                 break;
2080         case TCP_KEEPIDLE:
2081                 val = (tp->keepalive_time ? : sysctl_tcp_keepalive_time) / HZ;
2082                 break;
2083         case TCP_KEEPINTVL:
2084                 val = (tp->keepalive_intvl ? : sysctl_tcp_keepalive_intvl) / HZ;
2085                 break;
2086         case TCP_KEEPCNT:
2087                 val = tp->keepalive_probes ? : sysctl_tcp_keepalive_probes;
2088                 break;
2089         case TCP_SYNCNT:
2090                 val = icsk->icsk_syn_retries ? : sysctl_tcp_syn_retries;
2091                 break;
2092         case TCP_LINGER2:
2093                 val = tp->linger2;
2094                 if (val >= 0)
2095                         val = (val ? : sysctl_tcp_fin_timeout) / HZ;
2096                 break;
2097         case TCP_DEFER_ACCEPT:
2098                 val = !icsk->icsk_accept_queue.rskq_defer_accept ? 0 :
2099                         ((TCP_TIMEOUT_INIT / HZ) << (icsk->icsk_accept_queue.rskq_defer_accept - 1));
2100                 break;
2101         case TCP_WINDOW_CLAMP:
2102                 val = tp->window_clamp;
2103                 break;
2104         case TCP_INFO: {
2105                 struct tcp_info info;
2106
2107                 if (get_user(len, optlen))
2108                         return -EFAULT;
2109
2110                 tcp_get_info(sk, &info);
2111
2112                 len = min_t(unsigned int, len, sizeof(info));
2113                 if (put_user(len, optlen))
2114                         return -EFAULT;
2115                 if (copy_to_user(optval, &info, len))
2116                         return -EFAULT;
2117                 return 0;
2118         }
2119         case TCP_QUICKACK:
2120                 val = !icsk->icsk_ack.pingpong;
2121                 break;
2122
2123         case TCP_CONGESTION:
2124                 if (get_user(len, optlen))
2125                         return -EFAULT;
2126                 len = min_t(unsigned int, len, TCP_CA_NAME_MAX);
2127                 if (put_user(len, optlen))
2128                         return -EFAULT;
2129                 if (copy_to_user(optval, icsk->icsk_ca_ops->name, len))
2130                         return -EFAULT;
2131                 return 0;
2132         default:
2133                 return -ENOPROTOOPT;
2134         }
2135
2136         if (put_user(len, optlen))
2137                 return -EFAULT;
2138         if (copy_to_user(optval, &val, len))
2139                 return -EFAULT;
2140         return 0;
2141 }
2142
2143 int tcp_getsockopt(struct sock *sk, int level, int optname, char __user *optval,
2144                    int __user *optlen)
2145 {
2146         struct inet_connection_sock *icsk = inet_csk(sk);
2147
2148         if (level != SOL_TCP)
2149                 return icsk->icsk_af_ops->getsockopt(sk, level, optname,
2150                                                      optval, optlen);
2151         return do_tcp_getsockopt(sk, level, optname, optval, optlen);
2152 }
2153
2154 #ifdef CONFIG_COMPAT
2155 int compat_tcp_getsockopt(struct sock *sk, int level, int optname,
2156                           char __user *optval, int __user *optlen)
2157 {
2158         if (level != SOL_TCP)
2159                 return inet_csk_compat_getsockopt(sk, level, optname,
2160                                                   optval, optlen);
2161         return do_tcp_getsockopt(sk, level, optname, optval, optlen);
2162 }
2163
2164 EXPORT_SYMBOL(compat_tcp_getsockopt);
2165 #endif
2166
2167 struct sk_buff *tcp_tso_segment(struct sk_buff *skb, int features)
2168 {
2169         struct sk_buff *segs = ERR_PTR(-EINVAL);
2170         struct tcphdr *th;
2171         unsigned thlen;
2172         unsigned int seq;
2173         __be32 delta;
2174         unsigned int oldlen;
2175         unsigned int len;
2176
2177         if (!pskb_may_pull(skb, sizeof(*th)))
2178                 goto out;
2179
2180         th = tcp_hdr(skb);
2181         thlen = th->doff * 4;
2182         if (thlen < sizeof(*th))
2183                 goto out;
2184
2185         if (!pskb_may_pull(skb, thlen))
2186                 goto out;
2187
2188         oldlen = (u16)~skb->len;
2189         __skb_pull(skb, thlen);
2190
2191         if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) {
2192                 /* Packet is from an untrusted source, reset gso_segs. */
2193                 int type = skb_shinfo(skb)->gso_type;
2194                 int mss;
2195
2196                 if (unlikely(type &
2197                              ~(SKB_GSO_TCPV4 |
2198                                SKB_GSO_DODGY |
2199                                SKB_GSO_TCP_ECN |
2200                                SKB_GSO_TCPV6 |
2201                                0) ||
2202                              !(type & (SKB_GSO_TCPV4 | SKB_GSO_TCPV6))))
2203                         goto out;
2204
2205                 mss = skb_shinfo(skb)->gso_size;
2206                 skb_shinfo(skb)->gso_segs = (skb->len + mss - 1) / mss;
2207
2208                 segs = NULL;
2209                 goto out;
2210         }
2211
2212         segs = skb_segment(skb, features);
2213         if (IS_ERR(segs))
2214                 goto out;
2215
2216         len = skb_shinfo(skb)->gso_size;
2217         delta = htonl(oldlen + (thlen + len));
2218
2219         skb = segs;
2220         th = tcp_hdr(skb);
2221         seq = ntohl(th->seq);
2222
2223         do {
2224                 th->fin = th->psh = 0;
2225
2226                 th->check = ~csum_fold((__force __wsum)((__force u32)th->check +
2227                                        (__force u32)delta));
2228                 if (skb->ip_summed != CHECKSUM_PARTIAL)
2229                         th->check =
2230                              csum_fold(csum_partial(skb_transport_header(skb),
2231                                                     thlen, skb->csum));
2232
2233                 seq += len;
2234                 skb = skb->next;
2235                 th = tcp_hdr(skb);
2236
2237                 th->seq = htonl(seq);
2238                 th->cwr = 0;
2239         } while (skb->next);
2240
2241         delta = htonl(oldlen + (skb->tail - skb->transport_header) +
2242                       skb->data_len);
2243         th->check = ~csum_fold((__force __wsum)((__force u32)th->check +
2244                                 (__force u32)delta));
2245         if (skb->ip_summed != CHECKSUM_PARTIAL)
2246                 th->check = csum_fold(csum_partial(skb_transport_header(skb),
2247                                                    thlen, skb->csum));
2248
2249 out:
2250         return segs;
2251 }
2252 EXPORT_SYMBOL(tcp_tso_segment);
2253
2254 #ifdef CONFIG_TCP_MD5SIG
2255 static unsigned long tcp_md5sig_users;
2256 static struct tcp_md5sig_pool **tcp_md5sig_pool;
2257 static DEFINE_SPINLOCK(tcp_md5sig_pool_lock);
2258
2259 static void __tcp_free_md5sig_pool(struct tcp_md5sig_pool **pool)
2260 {
2261         int cpu;
2262         for_each_possible_cpu(cpu) {
2263                 struct tcp_md5sig_pool *p = *per_cpu_ptr(pool, cpu);
2264                 if (p) {
2265                         if (p->md5_desc.tfm)
2266                                 crypto_free_hash(p->md5_desc.tfm);
2267                         kfree(p);
2268                         p = NULL;
2269                 }
2270         }
2271         free_percpu(pool);
2272 }
2273
2274 void tcp_free_md5sig_pool(void)
2275 {
2276         struct tcp_md5sig_pool **pool = NULL;
2277
2278         spin_lock_bh(&tcp_md5sig_pool_lock);
2279         if (--tcp_md5sig_users == 0) {
2280                 pool = tcp_md5sig_pool;
2281                 tcp_md5sig_pool = NULL;
2282         }
2283         spin_unlock_bh(&tcp_md5sig_pool_lock);
2284         if (pool)
2285                 __tcp_free_md5sig_pool(pool);
2286 }
2287
2288 EXPORT_SYMBOL(tcp_free_md5sig_pool);
2289
2290 static struct tcp_md5sig_pool **__tcp_alloc_md5sig_pool(void)
2291 {
2292         int cpu;
2293         struct tcp_md5sig_pool **pool;
2294
2295         pool = alloc_percpu(struct tcp_md5sig_pool *);
2296         if (!pool)
2297                 return NULL;
2298
2299         for_each_possible_cpu(cpu) {
2300                 struct tcp_md5sig_pool *p;
2301                 struct crypto_hash *hash;
2302
2303                 p = kzalloc(sizeof(*p), GFP_KERNEL);
2304                 if (!p)
2305                         goto out_free;
2306                 *per_cpu_ptr(pool, cpu) = p;
2307
2308                 hash = crypto_alloc_hash("md5", 0, CRYPTO_ALG_ASYNC);
2309                 if (!hash || IS_ERR(hash))
2310                         goto out_free;
2311
2312                 p->md5_desc.tfm = hash;
2313         }
2314         return pool;
2315 out_free:
2316         __tcp_free_md5sig_pool(pool);
2317         return NULL;
2318 }
2319
2320 struct tcp_md5sig_pool **tcp_alloc_md5sig_pool(void)
2321 {
2322         struct tcp_md5sig_pool **pool;
2323         int alloc = 0;
2324
2325 retry:
2326         spin_lock_bh(&tcp_md5sig_pool_lock);
2327         pool = tcp_md5sig_pool;
2328         if (tcp_md5sig_users++ == 0) {
2329                 alloc = 1;
2330                 spin_unlock_bh(&tcp_md5sig_pool_lock);
2331         } else if (!pool) {
2332                 tcp_md5sig_users--;
2333                 spin_unlock_bh(&tcp_md5sig_pool_lock);
2334                 cpu_relax();
2335                 goto retry;
2336         } else
2337                 spin_unlock_bh(&tcp_md5sig_pool_lock);
2338
2339         if (alloc) {
2340                 /* we cannot hold spinlock here because this may sleep. */
2341                 struct tcp_md5sig_pool **p = __tcp_alloc_md5sig_pool();
2342                 spin_lock_bh(&tcp_md5sig_pool_lock);
2343                 if (!p) {
2344                         tcp_md5sig_users--;
2345                         spin_unlock_bh(&tcp_md5sig_pool_lock);
2346                         return NULL;
2347                 }
2348                 pool = tcp_md5sig_pool;
2349                 if (pool) {
2350                         /* oops, it has already been assigned. */
2351                         spin_unlock_bh(&tcp_md5sig_pool_lock);
2352                         __tcp_free_md5sig_pool(p);
2353                 } else {
2354                         tcp_md5sig_pool = pool = p;
2355                         spin_unlock_bh(&tcp_md5sig_pool_lock);
2356                 }
2357         }
2358         return pool;
2359 }
2360
2361 EXPORT_SYMBOL(tcp_alloc_md5sig_pool);
2362
2363 struct tcp_md5sig_pool *__tcp_get_md5sig_pool(int cpu)
2364 {
2365         struct tcp_md5sig_pool **p;
2366         spin_lock_bh(&tcp_md5sig_pool_lock);
2367         p = tcp_md5sig_pool;
2368         if (p)
2369                 tcp_md5sig_users++;
2370         spin_unlock_bh(&tcp_md5sig_pool_lock);
2371         return (p ? *per_cpu_ptr(p, cpu) : NULL);
2372 }
2373
2374 EXPORT_SYMBOL(__tcp_get_md5sig_pool);
2375
2376 void __tcp_put_md5sig_pool(void)
2377 {
2378         tcp_free_md5sig_pool();
2379 }
2380
2381 EXPORT_SYMBOL(__tcp_put_md5sig_pool);
2382 #endif
2383
2384 void tcp_done(struct sock *sk)
2385 {
2386         if(sk->sk_state == TCP_SYN_SENT || sk->sk_state == TCP_SYN_RECV)
2387                 TCP_INC_STATS_BH(TCP_MIB_ATTEMPTFAILS);
2388
2389         tcp_set_state(sk, TCP_CLOSE);
2390         tcp_clear_xmit_timers(sk);
2391
2392         sk->sk_shutdown = SHUTDOWN_MASK;
2393
2394         if (!sock_flag(sk, SOCK_DEAD))
2395                 sk->sk_state_change(sk);
2396         else
2397                 inet_csk_destroy_sock(sk);
2398 }
2399 EXPORT_SYMBOL_GPL(tcp_done);
2400
2401 extern void __skb_cb_too_small_for_tcp(int, int);
2402 extern struct tcp_congestion_ops tcp_reno;
2403
2404 static __initdata unsigned long thash_entries;
2405 static int __init set_thash_entries(char *str)
2406 {
2407         if (!str)
2408                 return 0;
2409         thash_entries = simple_strtoul(str, &str, 0);
2410         return 1;
2411 }
2412 __setup("thash_entries=", set_thash_entries);
2413
2414 void __init tcp_init(void)
2415 {
2416         struct sk_buff *skb = NULL;
2417         unsigned long limit;
2418         int order, i, max_share;
2419
2420         if (sizeof(struct tcp_skb_cb) > sizeof(skb->cb))
2421                 __skb_cb_too_small_for_tcp(sizeof(struct tcp_skb_cb),
2422                                            sizeof(skb->cb));
2423
2424         tcp_hashinfo.bind_bucket_cachep =
2425                 kmem_cache_create("tcp_bind_bucket",
2426                                   sizeof(struct inet_bind_bucket), 0,
2427                                   SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL);
2428
2429         /* Size and allocate the main established and bind bucket
2430          * hash tables.
2431          *
2432          * The methodology is similar to that of the buffer cache.
2433          */
2434         tcp_hashinfo.ehash =
2435                 alloc_large_system_hash("TCP established",
2436                                         sizeof(struct inet_ehash_bucket),
2437                                         thash_entries,
2438                                         (num_physpages >= 128 * 1024) ?
2439                                         13 : 15,
2440                                         0,
2441                                         &tcp_hashinfo.ehash_size,
2442                                         NULL,
2443                                         0);
2444         tcp_hashinfo.ehash_size = 1 << tcp_hashinfo.ehash_size;
2445         for (i = 0; i < tcp_hashinfo.ehash_size; i++) {
2446                 rwlock_init(&tcp_hashinfo.ehash[i].lock);
2447                 INIT_HLIST_HEAD(&tcp_hashinfo.ehash[i].chain);
2448                 INIT_HLIST_HEAD(&tcp_hashinfo.ehash[i].twchain);
2449         }
2450
2451         tcp_hashinfo.bhash =
2452                 alloc_large_system_hash("TCP bind",
2453                                         sizeof(struct inet_bind_hashbucket),
2454                                         tcp_hashinfo.ehash_size,
2455                                         (num_physpages >= 128 * 1024) ?
2456                                         13 : 15,
2457                                         0,
2458                                         &tcp_hashinfo.bhash_size,
2459                                         NULL,
2460                                         64 * 1024);
2461         tcp_hashinfo.bhash_size = 1 << tcp_hashinfo.bhash_size;
2462         for (i = 0; i < tcp_hashinfo.bhash_size; i++) {
2463                 spin_lock_init(&tcp_hashinfo.bhash[i].lock);
2464                 INIT_HLIST_HEAD(&tcp_hashinfo.bhash[i].chain);
2465         }
2466
2467         /* Try to be a bit smarter and adjust defaults depending
2468          * on available memory.
2469          */
2470         for (order = 0; ((1 << order) << PAGE_SHIFT) <
2471                         (tcp_hashinfo.bhash_size * sizeof(struct inet_bind_hashbucket));
2472                         order++)
2473                 ;
2474         if (order >= 4) {
2475                 tcp_death_row.sysctl_max_tw_buckets = 180000;
2476                 sysctl_tcp_max_orphans = 4096 << (order - 4);
2477                 sysctl_max_syn_backlog = 1024;
2478         } else if (order < 3) {
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);