net/ipv4/tcp.c

   1 /*
   2  * INET         An implementation of the TCP/IP protocol suite for the LINUX
   3  *              operating system.  INET is implemented using the  BSD Socket
   4  *              interface as the means of communication with the user level.
   5  *
   6  *              Implementation of the Transmission Control Protocol(TCP).
   7  *
   8  * Authors:     Ross Biro
   9  *              Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
  10  *              Mark Evans, <evansmp@uhura.aston.ac.uk>
  11  *              Corey Minyard <wf-rch!minyard@relay.EU.net>
  12  *              Florian La Roche, <flla@stud.uni-sb.de>
  13  *              Charles Hedrick, <hedrick@klinzhai.rutgers.edu>
  14  *              Linus Torvalds, <torvalds@cs.helsinki.fi>
  15  *              Alan Cox, <gw4pts@gw4pts.ampr.org>
  16  *              Matthew Dillon, <dillon@apollo.west.oic.com>
  17  *              Arnt Gulbrandsen, <agulbra@nvg.unit.no>
  18  *              Jorge Cwik, <jorge@laser.satlink.net>
  19  *
  20  * Fixes:
  21  *              Alan Cox        :       Numerous verify_area() calls
  22  *              Alan Cox        :       Set the ACK bit on a reset
  23  *              Alan Cox        :       Stopped it crashing if it closed while
  24  *                                      sk->inuse=1 and was trying to connect
  25  *                                      (tcp_err()).
  26  *              Alan Cox        :       All icmp error handling was broken
  27  *                                      pointers passed where wrong and the
  28  *                                      socket was looked up backwards. Nobody
  29  *                                      tested any icmp error code obviously.
  30  *              Alan Cox        :       tcp_err() now handled properly. It
  31  *                                      wakes people on errors. poll
  32  *                                      behaves and the icmp error race
  33  *                                      has gone by moving it into sock.c
  34  *              Alan Cox        :       tcp_send_reset() fixed to work for
  35  *                                      everything not just packets for
  36  *                                      unknown sockets.
  37  *              Alan Cox        :       tcp option processing.
  38  *              Alan Cox        :       Reset tweaked (still not 100%) [Had
  39  *                                      syn rule wrong]
  40  *              Herp Rosmanith  :       More reset fixes
  41  *              Alan Cox        :       No longer acks invalid rst frames.
  42  *                                      Acking any kind of RST is right out.
  43  *              Alan Cox        :       Sets an ignore me flag on an rst
  44  *                                      receive otherwise odd bits of prattle
  45  *                                      escape still
  46  *              Alan Cox        :       Fixed another acking RST frame bug.
  47  *                                      Should stop LAN workplace lockups.
  48  *              Alan Cox        :       Some tidyups using the new skb list
  49  *                                      facilities
  50  *              Alan Cox        :       sk->keepopen now seems to work
  51  *              Alan Cox        :       Pulls options out correctly on accepts
  52  *              Alan Cox        :       Fixed assorted sk->rqueue->next errors
  53  *              Alan Cox        :       PSH doesn't end a TCP read. Switched a
  54  *                                      bit to skb ops.
  55  *              Alan Cox        :       Tidied tcp_data to avoid a potential
  56  *                                      nasty.
  57  *              Alan Cox        :       Added some better commenting, as the
  58  *                                      tcp is hard to follow
  59  *              Alan Cox        :       Removed incorrect check for 20 * psh
  60  *      Michael O'Reilly        :       ack < copied bug fix.
  61  *      Johannes Stille         :       Misc tcp fixes (not all in yet).
  62  *              Alan Cox        :       FIN with no memory -> CRASH
  63  *              Alan Cox        :       Added socket option proto entries.
  64  *                                      Also added awareness of them to accept.
  65  *              Alan Cox        :       Added TCP options (SOL_TCP)
  66  *              Alan Cox        :       Switched wakeup calls to callbacks,
  67  *                                      so the kernel can layer network
  68  *                                      sockets.
  69  *              Alan Cox        :       Use ip_tos/ip_ttl settings.
  70  *              Alan Cox        :       Handle FIN (more) properly (we hope).
  71  *              Alan Cox        :       RST frames sent on unsynchronised
  72  *                                      state ack error.
  73  *              Alan Cox        :       Put in missing check for SYN bit.
  74  *              Alan Cox        :       Added tcp_select_window() aka NET2E
  75  *                                      window non shrink trick.
  76  *              Alan Cox        :       Added a couple of small NET2E timer
  77  *                                      fixes
  78  *              Charles Hedrick :       TCP fixes
  79  *              Toomas Tamm     :       TCP window fixes
  80  *              Alan Cox        :       Small URG fix to rlogin ^C ack fight
  81  *              Charles Hedrick :       Rewrote most of it to actually work
  82  *              Linus           :       Rewrote tcp_read() and URG handling
  83  *                                      completely
  84  *              Gerhard Koerting:       Fixed some missing timer handling
  85  *              Matthew Dillon  :       Reworked TCP machine states as per RFC
  86  *              Gerhard Koerting:       PC/TCP workarounds
  87  *              Adam Caldwell   :       Assorted timer/timing errors
  88  *              Matthew Dillon  :       Fixed another RST bug
  89  *              Alan Cox        :       Move to kernel side addressing changes.
  90  *              Alan Cox        :       Beginning work on TCP fastpathing
  91  *                                      (not yet usable)
  92  *              Arnt Gulbrandsen:       Turbocharged tcp_check() routine.
  93  *              Alan Cox        :       TCP fast path debugging
  94  *              Alan Cox        :       Window clamping
  95  *              Michael Riepe   :       Bug in tcp_check()
  96  *              Matt Dillon     :       More TCP improvements and RST bug fixes
  97  *              Matt Dillon     :       Yet more small nasties remove from the
  98  *                                      TCP code (Be very nice to this man if
  99  *                                      tcp finally works 100%) 8)
 100  *              Alan Cox        :       BSD accept semantics.
 101  *              Alan Cox        :       Reset on closedown bug.
 102  *      Peter De Schrijver      :       ENOTCONN check missing in tcp_sendto().
 103  *              Michael Pall    :       Handle poll() after URG properly in
 104  *                                      all cases.
 105  *              Michael Pall    :       Undo the last fix in tcp_read_urg()
 106  *                                      (multi URG PUSH broke rlogin).
 107  *              Michael Pall    :       Fix the multi URG PUSH problem in
 108  *                                      tcp_readable(), poll() after URG
 109  *                                      works now.
 110  *              Michael Pall    :       recv(...,MSG_OOB) never blocks in the
 111  *                                      BSD api.
 112  *              Alan Cox        :       Changed the semantics of sk->socket to
 113  *                                      fix a race and a signal problem with
 114  *                                      accept() and async I/O.
 115  *              Alan Cox        :       Relaxed the rules on tcp_sendto().
 116  *              Yury Shevchuk   :       Really fixed accept() blocking problem.
 117  *              Craig I. Hagan  :       Allow for BSD compatible TIME_WAIT for
 118  *                                      clients/servers which listen in on
 119  *                                      fixed ports.
 120  *              Alan Cox        :       Cleaned the above up and shrank it to
 121  *                                      a sensible code size.
 122  *              Alan Cox        :       Self connect lockup fix.
 123  *              Alan Cox        :       No connect to multicast.
 124  *              Ross Biro       :       Close unaccepted children on master
 125  *                                      socket close.
 126  *              Alan Cox        :       Reset tracing code.
 127  *              Alan Cox        :       Spurious resets on shutdown.
 128  *              Alan Cox        :       Giant 15 minute/60 second timer error
 129  *              Alan Cox        :       Small whoops in polling before an
 130  *                                      accept.
 131  *              Alan Cox        :       Kept the state trace facility since
 132  *                                      it's handy for debugging.
 133  *              Alan Cox        :       More reset handler fixes.
 134  *              Alan Cox        :       Started rewriting the code based on
 135  *                                      the RFC's for other useful protocol
 136  *                                      references see: Comer, KA9Q NOS, and
 137  *                                      for a reference on the difference
 138  *                                      between specifications and how BSD
 139  *                                      works see the 4.4lite source.
 140  *              A.N.Kuznetsov   :       Don't time wait on completion of tidy
 141  *                                      close.
 142  *              Linus Torvalds  :       Fin/Shutdown & copied_seq changes.
 143  *              Linus Torvalds  :       Fixed BSD port reuse to work first syn
 144  *              Alan Cox        :       Reimplemented timers as per the RFC
 145  *                                      and using multiple timers for sanity.
 146  *              Alan Cox        :       Small bug fixes, and a lot of new
 147  *                                      comments.
 148  *              Alan Cox        :       Fixed dual reader crash by locking
 149  *                                      the buffers (much like datagram.c)
 150  *              Alan Cox        :       Fixed stuck sockets in probe. A probe
 151  *                                      now gets fed up of retrying without
 152  *                                      (even a no space) answer.
 153  *              Alan Cox        :       Extracted closing code better
 154  *              Alan Cox        :       Fixed the closing state machine to
 155  *                                      resemble the RFC.
 156  *              Alan Cox        :       More 'per spec' fixes.
 157  *              Jorge Cwik      :       Even faster checksumming.
 158  *              Alan Cox        :       tcp_data() doesn't ack illegal PSH
 159  *                                      only frames. At least one pc tcp stack
 160  *                                      generates them.
 161  *              Alan Cox        :       Cache last socket.
 162  *              Alan Cox        :       Per route irtt.
 163  *              Matt Day        :       poll()->select() match BSD precisely on error
 164  *              Alan Cox        :       New buffers
 165  *              Marc Tamsky     :       Various sk->prot->retransmits and
 166  *                                      sk->retransmits misupdating fixed.
 167  *                                      Fixed tcp_write_timeout: stuck close,
 168  *                                      and TCP syn retries gets used now.
 169  *              Mark Yarvis     :       In tcp_read_wakeup(), don't send an
 170  *                                      ack if state is TCP_CLOSED.
 171  *              Alan Cox        :       Look up device on a retransmit - routes may
 172  *                                      change. Doesn't yet cope with MSS shrink right
 173  *                                      but it's a start!
 174  *              Marc Tamsky     :       Closing in closing fixes.
 175  *              Mike Shaver     :       RFC1122 verifications.
 176  *              Alan Cox        :       rcv_saddr errors.
 177  *              Alan Cox        :       Block double connect().
 178  *              Alan Cox        :       Small hooks for enSKIP.
 179  *              Alexey Kuznetsov:       Path MTU discovery.
 180  *              Alan Cox        :       Support soft errors.
 181  *              Alan Cox        :       Fix MTU discovery pathological case
 182  *                                      when the remote claims no mtu!
 183  *              Marc Tamsky     :       TCP_CLOSE fix.
 184  *              Colin (G3TNE)   :       Send a reset on syn ack replies in
 185  *                                      window but wrong (fixes NT lpd problems)
 186  *              Pedro Roque     :       Better TCP window handling, delayed ack.
 187  *              Joerg Reuter    :       No modification of locked buffers in
 188  *                                      tcp_do_retransmit()
 189  *              Eric Schenk     :       Changed receiver side silly window
 190  *                                      avoidance algorithm to BSD style
 191  *                                      algorithm. This doubles throughput
 192  *                                      against machines running Solaris,
 193  *                                      and seems to result in general
 194  *                                      improvement.
 195  *      Stefan Magdalinski      :       adjusted tcp_readable() to fix FIONREAD
 196  *      Willy Konynenberg       :       Transparent proxying support.
 197  *      Mike McLagan            :       Routing by source
 198  *              Keith Owens     :       Do proper merging with partial SKB's in
 199  *                                      tcp_do_sendmsg to avoid burstiness.
 200  *              Eric Schenk     :       Fix fast close down bug with
 201  *                                      shutdown() followed by close().
 202  *              Andi Kleen      :       Make poll agree with SIGIO
 203  *      Salvatore Sanfilippo    :       Support SO_LINGER with linger == 1 and
 204  *                                      lingertime == 0 (RFC 793 ABORT Call)
 205  *      Hirokazu Takahashi      :       Use copy_from_user() instead of
 206  *                                      csum_and_copy_from_user() if possible.
 207  *
 208  *              This program is free software; you can redistribute it and/or
 209  *              modify it under the terms of the GNU General Public License
 210  *              as published by the Free Software Foundation; either version
 211  *              2 of the License, or(at your option) any later version.
 212  *
 213  * Description of States:
 214  *
 215  *      TCP_SYN_SENT            sent a connection request, waiting for ack
 216  *
 217  *      TCP_SYN_RECV            received a connection request, sent ack,
 218  *                              waiting for final ack in three-way handshake.
 219  *
 220  *      TCP_ESTABLISHED         connection established
 221  *
 222  *      TCP_FIN_WAIT1           our side has shutdown, waiting to complete
 223  *                              transmission of remaining buffered data
 224  *
 225  *      TCP_FIN_WAIT2           all buffered data sent, waiting for remote
 226  *                              to shutdown
 227  *
 228  *      TCP_CLOSING             both sides have shutdown but we still have
 229  *                              data we have to finish sending
 230  *
 231  *      TCP_TIME_WAIT           timeout to catch resent junk before entering
 232  *                              closed, can only be entered from FIN_WAIT2
 233  *                              or CLOSING.  Required because the other end
 234  *                              may not have gotten our last ACK causing it
 235  *                              to retransmit the data packet (which we ignore)
 236  *
 237  *      TCP_CLOSE_WAIT          remote side has shutdown and is waiting for
 238  *                              us to finish writing our data and to shutdown
 239  *                              (we have to close() to move on to LAST_ACK)
 240  *
 241  *      TCP_LAST_ACK            out side has shutdown after remote has
 242  *                              shutdown.  There may still be data in our
 243  *                              buffer that we have to finish sending
 244  *
 245  *      TCP_CLOSE               socket is finished
 246  */
 247
 248 #define pr_fmt(fmt) "TCP: " fmt
 249
 250 #include <linux/kernel.h>
 251 #include <linux/module.h>
 252 #include <linux/types.h>
 253 #include <linux/fcntl.h>
 254 #include <linux/poll.h>
 255 #include <linux/init.h>
 256 #include <linux/fs.h>
 257 #include <linux/skbuff.h>
 258 #include <linux/scatterlist.h>
 259 #include <linux/splice.h>
 260 #include <linux/net.h>
 261 #include <linux/socket.h>
 262 #include <linux/random.h>
 263 #include <linux/bootmem.h>
 264 #include <linux/highmem.h>
 265 #include <linux/swap.h>
 266 #include <linux/cache.h>
 267 #include <linux/err.h>
 268 #include <linux/crypto.h>
 269 #include <linux/time.h>
 270 #include <linux/slab.h>
 271
 272 #include <net/icmp.h>
 273 #include <net/tcp.h>
 274 #include <net/xfrm.h>
 275 #include <net/ip.h>
 276 #include <net/netdma.h>
 277 #include <net/sock.h>
 278
 279 #include <asm/uaccess.h>
 280 #include <asm/ioctls.h>
 281
 282 int sysctl_tcp_fin_timeout __read_mostly = TCP_FIN_TIMEOUT;
 283
 284 struct percpu_counter tcp_orphan_count;
 285 EXPORT_SYMBOL_GPL(tcp_orphan_count);
 286
 287 int sysctl_tcp_wmem[3] __read_mostly;
 288 int sysctl_tcp_rmem[3] __read_mostly;
 289
 290 EXPORT_SYMBOL(sysctl_tcp_rmem);
 291 EXPORT_SYMBOL(sysctl_tcp_wmem);
 292
 293 atomic_long_t tcp_memory_allocated;     /* Current allocated memory. */
 294 EXPORT_SYMBOL(tcp_memory_allocated);
 295
 296 /*
 297  * Current number of TCP sockets.
 298  */
 299 struct percpu_counter tcp_sockets_allocated;
 300 EXPORT_SYMBOL(tcp_sockets_allocated);
 301
 302 /*
 303  * TCP splice context
 304  */
 305 struct tcp_splice_state {
 306         struct pipe_inode_info *pipe;
 307         size_t len;
 308         unsigned int flags;
 309 };
 310
 311 /*
 312  * Pressure flag: try to collapse.
 313  * Technical note: it is used by multiple contexts non atomically.
 314  * All the __sk_mem_schedule() is of this nature: accounting
 315  * is strict, actions are advisory and have some latency.
 316  */
 317 int tcp_memory_pressure __read_mostly;
 318 EXPORT_SYMBOL(tcp_memory_pressure);
 319
 320 void tcp_enter_memory_pressure(struct sock *sk)
 321 {
 322         if (!tcp_memory_pressure) {
 323                 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMEMORYPRESSURES);
 324                 tcp_memory_pressure = 1;
 325         }
 326 }
 327 EXPORT_SYMBOL(tcp_enter_memory_pressure);
 328
 329 /* Convert seconds to retransmits based on initial and max timeout */
 330 static u8 secs_to_retrans(int seconds, int timeout, int rto_max)
 331 {
 332         u8 res = 0;
 333
 334         if (seconds > 0) {
 335                 int period = timeout;
 336
 337                 res = 1;
 338                 while (seconds > period && res < 255) {
 339                         res++;
 340                         timeout <<= 1;
 341                         if (timeout > rto_max)
 342                                 timeout = rto_max;
 343                         period += timeout;
 344                 }
 345         }
 346         return res;
 347 }
 348
 349 /* Convert retransmits to seconds based on initial and max timeout */
 350 static int retrans_to_secs(u8 retrans, int timeout, int rto_max)
 351 {
 352         int period = 0;
 353
 354         if (retrans > 0) {
 355                 period = timeout;
 356                 while (--retrans) {
 357                         timeout <<= 1;
 358                         if (timeout > rto_max)
 359                                 timeout = rto_max;
 360                         period += timeout;
 361                 }
 362         }
 363         return period;
 364 }
 365
 366 /* Address-family independent initialization for a tcp_sock.
 367  *
 368  * NOTE: A lot of things set to zero explicitly by call to
 369  *       sk_alloc() so need not be done here.
 370  */
 371 void tcp_init_sock(struct sock *sk)
 372 {
 373         struct inet_connection_sock *icsk = inet_csk(sk);
 374         struct tcp_sock *tp = tcp_sk(sk);
 375
 376         skb_queue_head_init(&tp->out_of_order_queue);
 377         tcp_init_xmit_timers(sk);
 378         tcp_prequeue_init(tp);
 379
 380         icsk->icsk_rto = TCP_TIMEOUT_INIT;
 381         tp->mdev = TCP_TIMEOUT_INIT;
 382
 383         /* So many TCP implementations out there (incorrectly) count the
 384          * initial SYN frame in their delayed-ACK and congestion control
 385          * algorithms that we must have the following bandaid to talk
 386          * efficiently to them.  -DaveM
 387          */
 388         tp->snd_cwnd = TCP_INIT_CWND;
 389
 390         /* See draft-stevens-tcpca-spec-01 for discussion of the
 391          * initialization of these values.
 392          */
 393         tp->snd_ssthresh = TCP_INFINITE_SSTHRESH;
 394         tp->snd_cwnd_clamp = ~0;
 395         tp->mss_cache = TCP_MSS_DEFAULT;
 396
 397         tp->reordering = sysctl_tcp_reordering;
 398         icsk->icsk_ca_ops = &tcp_init_congestion_ops;
 399
 400         sk->sk_state = TCP_CLOSE;
 401
 402         sk->sk_write_space = sk_stream_write_space;
 403         sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
 404
 405         icsk->icsk_sync_mss = tcp_sync_mss;
 406
 407         /* TCP Cookie Transactions */
 408         if (sysctl_tcp_cookie_size > 0) {
 409                 /* Default, cookies without s_data_payload. */
 410                 tp->cookie_values =
 411                         kzalloc(sizeof(*tp->cookie_values),
 412                                 sk->sk_allocation);
 413                 if (tp->cookie_values != NULL)
 414                         kref_init(&tp->cookie_values->kref);
 415         }
 416         /* Presumed zeroed, in order of appearance:
 417          *      cookie_in_always, cookie_out_never,
 418          *      s_data_constant, s_data_in, s_data_out
 419          */
 420         sk->sk_sndbuf = sysctl_tcp_wmem[1];
 421         sk->sk_rcvbuf = sysctl_tcp_rmem[1];
 422
 423         local_bh_disable();
 424         sock_update_memcg(sk);
 425         sk_sockets_allocated_inc(sk);
 426         local_bh_enable();
 427 }
 428 EXPORT_SYMBOL(tcp_init_sock);
 429
 430 /*
 431  *      Wait for a TCP event.
 432  *
 433  *      Note that we don't need to lock the socket, as the upper poll layers
 434  *      take care of normal races (between the test and the event) and we don't
 435  *      go look at any of the socket buffers directly.
 436  */
 437 unsigned int tcp_poll(struct file *file, struct socket *sock, poll_table *wait)
 438 {
 439         unsigned int mask;
 440         struct sock *sk = sock->sk;
 441         const struct tcp_sock *tp = tcp_sk(sk);
 442
 443         sock_poll_wait(file, sk_sleep(sk), wait);
 444         if (sk->sk_state == TCP_LISTEN)
 445                 return inet_csk_listen_poll(sk);
 446
 447         /* Socket is not locked. We are protected from async events
 448          * by poll logic and correct handling of state changes
 449          * made by other threads is impossible in any case.
 450          */
 451
 452         mask = 0;
 453
 454         /*
 455          * POLLHUP is certainly not done right. But poll() doesn't
 456          * have a notion of HUP in just one direction, and for a
 457          * socket the read side is more interesting.
 458          *
 459          * Some poll() documentation says that POLLHUP is incompatible
 460          * with the POLLOUT/POLLWR flags, so somebody should check this
 461          * all. But careful, it tends to be safer to return too many
 462          * bits than too few, and you can easily break real applications
 463          * if you don't tell them that something has hung up!
 464          *
 465          * Check-me.
 466          *
 467          * Check number 1. POLLHUP is _UNMASKABLE_ event (see UNIX98 and
 468          * our fs/select.c). It means that after we received EOF,
 469          * poll always returns immediately, making impossible poll() on write()
 470          * in state CLOSE_WAIT. One solution is evident --- to set POLLHUP
 471          * if and only if shutdown has been made in both directions.
 472          * Actually, it is interesting to look how Solaris and DUX
 473          * solve this dilemma. I would prefer, if POLLHUP were maskable,
 474          * then we could set it on SND_SHUTDOWN. BTW examples given
 475          * in Stevens' books assume exactly this behaviour, it explains
 476          * why POLLHUP is incompatible with POLLOUT.    --ANK
 477          *
 478          * NOTE. Check for TCP_CLOSE is added. The goal is to prevent
 479          * blocking on fresh not-connected or disconnected socket. --ANK
 480          */
 481         if (sk->sk_shutdown == SHUTDOWN_MASK || sk->sk_state == TCP_CLOSE)
 482                 mask |= POLLHUP;
 483         if (sk->sk_shutdown & RCV_SHUTDOWN)
 484                 mask |= POLLIN | POLLRDNORM | POLLRDHUP;
 485
 486         /* Connected? */
 487         if ((1 << sk->sk_state) & ~(TCPF_SYN_SENT | TCPF_SYN_RECV)) {
 488                 int target = sock_rcvlowat(sk, 0, INT_MAX);
 489
 490                 if (tp->urg_seq == tp->copied_seq &&
 491                     !sock_flag(sk, SOCK_URGINLINE) &&
 492                     tp->urg_data)
 493                         target++;
 494
 495                 /* Potential race condition. If read of tp below will
 496                  * escape above sk->sk_state, we can be illegally awaken
 497                  * in SYN_* states. */
 498                 if (tp->rcv_nxt - tp->copied_seq >= target)
 499                         mask |= POLLIN | POLLRDNORM;
 500
 501                 if (!(sk->sk_shutdown & SEND_SHUTDOWN)) {
 502                         if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk)) {
 503                                 mask |= POLLOUT | POLLWRNORM;
 504                         } else {  /* send SIGIO later */
 505                                 set_bit(SOCK_ASYNC_NOSPACE,
 506                                         &sk->sk_socket->flags);
 507                                 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
 508
 509                                 /* Race breaker. If space is freed after
 510                                  * wspace test but before the flags are set,
 511                                  * IO signal will be lost.
 512                                  */
 513                                 if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk))
 514                                         mask |= POLLOUT | POLLWRNORM;
 515                         }
 516                 } else
 517                         mask |= POLLOUT | POLLWRNORM;
 518
 519                 if (tp->urg_data & TCP_URG_VALID)
 520                         mask |= POLLPRI;
 521         }
 522         /* This barrier is coupled with smp_wmb() in tcp_reset() */
 523         smp_rmb();
 524         if (sk->sk_err)
 525                 mask |= POLLERR;
 526
 527         return mask;
 528 }
 529 EXPORT_SYMBOL(tcp_poll);
 530
 531 int tcp_ioctl(struct sock *sk, int cmd, unsigned long arg)
 532 {
 533         struct tcp_sock *tp = tcp_sk(sk);
 534         int answ;
 535
 536         switch (cmd) {
 537         case SIOCINQ:
 538                 if (sk->sk_state == TCP_LISTEN)
 539                         return -EINVAL;
 540
 541                 lock_sock(sk);
 542                 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
 543                         answ = 0;
 544                 else if (sock_flag(sk, SOCK_URGINLINE) ||
 545                          !tp->urg_data ||
 546                          before(tp->urg_seq, tp->copied_seq) ||
 547                          !before(tp->urg_seq, tp->rcv_nxt)) {
 548                         struct sk_buff *skb;
 549
 550                         answ = tp->rcv_nxt - tp->copied_seq;
 551
 552                         /* Subtract 1, if FIN is in queue. */
 553                         skb = skb_peek_tail(&sk->sk_receive_queue);
 554                         if (answ && skb)
 555                                 answ -= tcp_hdr(skb)->fin;
 556                 } else
 557                         answ = tp->urg_seq - tp->copied_seq;
 558                 release_sock(sk);
 559                 break;
 560         case SIOCATMARK:
 561                 answ = tp->urg_data && tp->urg_seq == tp->copied_seq;
 562                 break;
 563         case SIOCOUTQ:
 564                 if (sk->sk_state == TCP_LISTEN)
 565                         return -EINVAL;
 566
 567                 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
 568                         answ = 0;
 569                 else
 570                         answ = tp->write_seq - tp->snd_una;
 571                 break;
 572         case SIOCOUTQNSD:
 573                 if (sk->sk_state == TCP_LISTEN)
 574                         return -EINVAL;
 575
 576                 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
 577                         answ = 0;
 578                 else
 579                         answ = tp->write_seq - tp->snd_nxt;
 580                 break;
 581         default:
 582                 return -ENOIOCTLCMD;
 583         }
 584
 585         return put_user(answ, (int __user *)arg);
 586 }
 587 EXPORT_SYMBOL(tcp_ioctl);
 588
 589 static inline void tcp_mark_push(struct tcp_sock *tp, struct sk_buff *skb)
 590 {
 591         TCP_SKB_CB(skb)->tcp_flags |= TCPHDR_PSH;
 592         tp->pushed_seq = tp->write_seq;
 593 }
 594
 595 static inline int forced_push(const struct tcp_sock *tp)
 596 {
 597         return after(tp->write_seq, tp->pushed_seq + (tp->max_window >> 1));
 598 }
 599
 600 static inline void skb_entail(struct sock *sk, struct sk_buff *skb)
 601 {
 602         struct tcp_sock *tp = tcp_sk(sk);
 603         struct tcp_skb_cb *tcb = TCP_SKB_CB(skb);
 604
 605         skb->csum    = 0;
 606         tcb->seq     = tcb->end_seq = tp->write_seq;
 607         tcb->tcp_flags = TCPHDR_ACK;
 608         tcb->sacked  = 0;
 609         skb_header_release(skb);
 610         tcp_add_write_queue_tail(sk, skb);
 611         sk->sk_wmem_queued += skb->truesize;
 612         sk_mem_charge(sk, skb->truesize);
 613         if (tp->nonagle & TCP_NAGLE_PUSH)
 614                 tp->nonagle &= ~TCP_NAGLE_PUSH;
 615 }
 616
 617 static inline void tcp_mark_urg(struct tcp_sock *tp, int flags)
 618 {
 619         if (flags & MSG_OOB)
 620                 tp->snd_up = tp->write_seq;
 621 }
 622
 623 static inline void tcp_push(struct sock *sk, int flags, int mss_now,
 624                             int nonagle)
 625 {
 626         if (tcp_send_head(sk)) {
 627                 struct tcp_sock *tp = tcp_sk(sk);
 628
 629                 if (!(flags & MSG_MORE) || forced_push(tp))
 630                         tcp_mark_push(tp, tcp_write_queue_tail(sk));
 631
 632                 tcp_mark_urg(tp, flags);
 633                 __tcp_push_pending_frames(sk, mss_now,
 634                                           (flags & MSG_MORE) ? TCP_NAGLE_CORK : nonagle);
 635         }
 636 }
 637
 638 static int tcp_splice_data_recv(read_descriptor_t *rd_desc, struct sk_buff *skb,
 639                                 unsigned int offset, size_t len)
 640 {
 641         struct tcp_splice_state *tss = rd_desc->arg.data;
 642         int ret;
 643
 644         ret = skb_splice_bits(skb, offset, tss->pipe, min(rd_desc->count, len),
 645                               tss->flags);
 646         if (ret > 0)
 647                 rd_desc->count -= ret;
 648         return ret;
 649 }
 650
 651 static int __tcp_splice_read(struct sock *sk, struct tcp_splice_state *tss)
 652 {
 653         /* Store TCP splice context information in read_descriptor_t. */
 654         read_descriptor_t rd_desc = {
 655                 .arg.data = tss,
 656                 .count    = tss->len,
 657         };
 658
 659         return tcp_read_sock(sk, &rd_desc, tcp_splice_data_recv);
 660 }
 661
 662 /**
 663  *  tcp_splice_read - splice data from TCP socket to a pipe
 664  * @sock:       socket to splice from
 665  * @ppos:       position (not valid)
 666  * @pipe:       pipe to splice to
 667  * @len:        number of bytes to splice
 668  * @flags:      splice modifier flags
 669  *
 670  * Description:
 671  *    Will read pages from given socket and fill them into a pipe.
 672  *
 673  **/
 674 ssize_t tcp_splice_read(struct socket *sock, loff_t *ppos,
 675                         struct pipe_inode_info *pipe, size_t len,
 676                         unsigned int flags)
 677 {
 678         struct sock *sk = sock->sk;
 679         struct tcp_splice_state tss = {
 680                 .pipe = pipe,
 681                 .len = len,
 682                 .flags = flags,
 683         };
 684         long timeo;
 685         ssize_t spliced;
 686         int ret;
 687
 688         sock_rps_record_flow(sk);
 689         /*
 690          * We can't seek on a socket input
 691          */
 692         if (unlikely(*ppos))
 693                 return -ESPIPE;
 694
 695         ret = spliced = 0;
 696
 697         lock_sock(sk);
 698
 699         timeo = sock_rcvtimeo(sk, sock->file->f_flags & O_NONBLOCK);
 700         while (tss.len) {
 701                 ret = __tcp_splice_read(sk, &tss);
 702                 if (ret < 0)
 703                         break;
 704                 else if (!ret) {
 705                         if (spliced)
 706                                 break;
 707                         if (sock_flag(sk, SOCK_DONE))
 708                                 break;
 709                         if (sk->sk_err) {
 710                                 ret = sock_error(sk);
 711                                 break;
 712                         }
 713                         if (sk->sk_shutdown & RCV_SHUTDOWN)
 714                                 break;
 715                         if (sk->sk_state == TCP_CLOSE) {
 716                                 /*
 717                                  * This occurs when user tries to read
 718                                  * from never connected socket.
 719                                  */
 720                                 if (!sock_flag(sk, SOCK_DONE))
 721                                         ret = -ENOTCONN;
 722                                 break;
 723                         }
 724                         if (!timeo) {
 725                                 ret = -EAGAIN;
 726                                 break;
 727                         }
 728                         sk_wait_data(sk, &timeo);
 729                         if (signal_pending(current)) {
 730                                 ret = sock_intr_errno(timeo);
 731                                 break;
 732                         }
 733                         continue;
 734                 }
 735                 tss.len -= ret;
 736                 spliced += ret;
 737
 738                 if (!timeo)
 739                         break;
 740                 release_sock(sk);
 741                 lock_sock(sk);
 742
 743                 if (sk->sk_err || sk->sk_state == TCP_CLOSE ||
 744                     (sk->sk_shutdown & RCV_SHUTDOWN) ||
 745                     signal_pending(current))
 746                         break;
 747         }
 748
 749         release_sock(sk);
 750
 751         if (spliced)
 752                 return spliced;
 753
 754         return ret;
 755 }
 756 EXPORT_SYMBOL(tcp_splice_read);
 757
 758 struct sk_buff *sk_stream_alloc_skb(struct sock *sk, int size, gfp_t gfp)
 759 {
 760         struct sk_buff *skb;
 761
 762         /* The TCP header must be at least 32-bit aligned.  */
 763         size = ALIGN(size, 4);
 764
 765         skb = alloc_skb_fclone(size + sk->sk_prot->max_header, gfp);
 766         if (skb) {
 767                 if (sk_wmem_schedule(sk, skb->truesize)) {
 768                         skb_reserve(skb, sk->sk_prot->max_header);
 769                         /*
 770                          * Make sure that we have exactly size bytes
 771                          * available to the caller, no more, no less.
 772                          */
 773                         skb->avail_size = size;
 774                         return skb;
 775                 }
 776                 __kfree_skb(skb);
 777         } else {
 778                 sk->sk_prot->enter_memory_pressure(sk);
 779                 sk_stream_moderate_sndbuf(sk);
 780         }
 781         return NULL;
 782 }
 783
 784 static unsigned int tcp_xmit_size_goal(struct sock *sk, u32 mss_now,
 785                                        int large_allowed)
 786 {
 787         struct tcp_sock *tp = tcp_sk(sk);
 788         u32 xmit_size_goal, old_size_goal;
 789
 790         xmit_size_goal = mss_now;
 791
 792         if (large_allowed && sk_can_gso(sk)) {
 793                 xmit_size_goal = ((sk->sk_gso_max_size - 1) -
 794                                   inet_csk(sk)->icsk_af_ops->net_header_len -
 795                                   inet_csk(sk)->icsk_ext_hdr_len -
 796                                   tp->tcp_header_len);
 797
 798                 xmit_size_goal = tcp_bound_to_half_wnd(tp, xmit_size_goal);
 799
 800                 /* We try hard to avoid divides here */
 801                 old_size_goal = tp->xmit_size_goal_segs * mss_now;
 802
 803                 if (likely(old_size_goal <= xmit_size_goal &&
 804                            old_size_goal + mss_now > xmit_size_goal)) {
 805                         xmit_size_goal = old_size_goal;
 806                 } else {
 807                         tp->xmit_size_goal_segs = xmit_size_goal / mss_now;
 808                         xmit_size_goal = tp->xmit_size_goal_segs * mss_now;
 809                 }
 810         }
 811
 812         return max(xmit_size_goal, mss_now);
 813 }
 814
 815 static int tcp_send_mss(struct sock *sk, int *size_goal, int flags)
 816 {
 817         int mss_now;
 818
 819         mss_now = tcp_current_mss(sk);
 820         *size_goal = tcp_xmit_size_goal(sk, mss_now, !(flags & MSG_OOB));
 821
 822         return mss_now;
 823 }
 824
 825 static ssize_t do_tcp_sendpages(struct sock *sk, struct page **pages, int poffset,
 826                          size_t psize, int flags)
 827 {
 828         struct tcp_sock *tp = tcp_sk(sk);
 829         int mss_now, size_goal;
 830         int err;
 831         ssize_t copied;
 832         long timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
 833
 834         /* Wait for a connection to finish. */
 835         if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT))
 836                 if ((err = sk_stream_wait_connect(sk, &timeo)) != 0)
 837                         goto out_err;
 838
 839         clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
 840
 841         mss_now = tcp_send_mss(sk, &size_goal, flags);
 842         copied = 0;
 843
 844         err = -EPIPE;
 845         if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
 846                 goto out_err;
 847
 848         while (psize > 0) {
 849                 struct sk_buff *skb = tcp_write_queue_tail(sk);
 850                 struct page *page = pages[poffset / PAGE_SIZE];
 851                 int copy, i;
 852                 int offset = poffset % PAGE_SIZE;
 853                 int size = min_t(size_t, psize, PAGE_SIZE - offset);
 854                 bool can_coalesce;
 855
 856                 if (!tcp_send_head(sk) || (copy = size_goal - skb->len) <= 0) {
 857 new_segment:
 858                         if (!sk_stream_memory_free(sk))
 859                                 goto wait_for_sndbuf;
 860
 861                         skb = sk_stream_alloc_skb(sk, 0, sk->sk_allocation);
 862                         if (!skb)
 863                                 goto wait_for_memory;
 864
 865                         skb_entail(sk, skb);
 866                         copy = size_goal;
 867                 }
 868
 869                 if (copy > size)
 870                         copy = size;
 871
 872                 i = skb_shinfo(skb)->nr_frags;
 873                 can_coalesce = skb_can_coalesce(skb, i, page, offset);
 874                 if (!can_coalesce && i >= MAX_SKB_FRAGS) {
 875                         tcp_mark_push(tp, skb);
 876                         goto new_segment;
 877                 }
 878                 if (!sk_wmem_schedule(sk, copy))
 879                         goto wait_for_memory;
 880
 881                 if (can_coalesce) {
 882                         skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy);
 883                 } else {
 884                         get_page(page);
 885                         skb_fill_page_desc(skb, i, page, offset, copy);
 886                 }
 887
 888                 skb->len += copy;
 889                 skb->data_len += copy;
 890                 skb->truesize += copy;
 891                 sk->sk_wmem_queued += copy;
 892                 sk_mem_charge(sk, copy);
 893                 skb->ip_summed = CHECKSUM_PARTIAL;
 894                 tp->write_seq += copy;
 895                 TCP_SKB_CB(skb)->end_seq += copy;
 896                 skb_shinfo(skb)->gso_segs = 0;
 897
 898                 if (!copied)
 899                         TCP_SKB_CB(skb)->tcp_flags &= ~TCPHDR_PSH;
 900
 901                 copied += copy;
 902                 poffset += copy;
 903                 if (!(psize -= copy))
 904                         goto out;
 905
 906                 if (skb->len < size_goal || (flags & MSG_OOB))
 907                         continue;
 908
 909                 if (forced_push(tp)) {
 910                         tcp_mark_push(tp, skb);
 911                         __tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH);
 912                 } else if (skb == tcp_send_head(sk))
 913                         tcp_push_one(sk, mss_now);
 914                 continue;
 915
 916 wait_for_sndbuf:
 917                 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
 918 wait_for_memory:
 919                 if (copied)
 920                         tcp_push(sk, flags & ~MSG_MORE, mss_now, TCP_NAGLE_PUSH);
 921
 922                 if ((err = sk_stream_wait_memory(sk, &timeo)) != 0)
 923                         goto do_error;
 924
 925                 mss_now = tcp_send_mss(sk, &size_goal, flags);
 926         }
 927
 928 out:
 929         if (copied && !(flags & MSG_SENDPAGE_NOTLAST))
 930                 tcp_push(sk, flags, mss_now, tp->nonagle);
 931         return copied;
 932
 933 do_error:
 934         if (copied)
 935                 goto out;
 936 out_err:
 937         return sk_stream_error(sk, flags, err);
 938 }
 939
 940 int tcp_sendpage(struct sock *sk, struct page *page, int offset,
 941                  size_t size, int flags)
 942 {
 943         ssize_t res;
 944
 945         if (!(sk->sk_route_caps & NETIF_F_SG) ||
 946             !(sk->sk_route_caps & NETIF_F_ALL_CSUM))
 947                 return sock_no_sendpage(sk->sk_socket, page, offset, size,
 948                                         flags);
 949
 950         lock_sock(sk);
 951         res = do_tcp_sendpages(sk, &page, offset, size, flags);
 952         release_sock(sk);
 953         return res;
 954 }
 955 EXPORT_SYMBOL(tcp_sendpage);
 956
 957 static inline int select_size(const struct sock *sk, bool sg)
 958 {
 959         const struct tcp_sock *tp = tcp_sk(sk);
 960         int tmp = tp->mss_cache;
 961
 962         if (sg) {
 963                 if (sk_can_gso(sk)) {
 964                         /* Small frames wont use a full page:
 965                          * Payload will immediately follow tcp header.
 966                          */
 967                         tmp = SKB_WITH_OVERHEAD(2048 - MAX_TCP_HEADER);
 968                 } else {
 969                         int pgbreak = SKB_MAX_HEAD(MAX_TCP_HEADER);
 970
 971                         if (tmp >= pgbreak &&
 972                             tmp <= pgbreak + (MAX_SKB_FRAGS - 1) * PAGE_SIZE)
 973                                 tmp = pgbreak;
 974                 }
 975         }
 976
 977         return tmp;
 978 }
 979
 980 static int tcp_send_rcvq(struct sock *sk, struct msghdr *msg, size_t size)
 981 {
 982         struct sk_buff *skb;
 983         struct tcp_skb_cb *cb;
 984         struct tcphdr *th;
 985
 986         skb = alloc_skb(size + sizeof(*th), sk->sk_allocation);
 987         if (!skb)
 988                 goto err;
 989
 990         th = (struct tcphdr *)skb_put(skb, sizeof(*th));
 991         skb_reset_transport_header(skb);
 992         memset(th, 0, sizeof(*th));
 993
 994         if (memcpy_fromiovec(skb_put(skb, size), msg->msg_iov, size))
 995                 goto err_free;
 996
 997         cb = TCP_SKB_CB(skb);
 998
 999         TCP_SKB_CB(skb)->seq = tcp_sk(sk)->rcv_nxt;
1000         TCP_SKB_CB(skb)->end_seq = TCP_SKB_CB(skb)->seq + size;
1001         TCP_SKB_CB(skb)->ack_seq = tcp_sk(sk)->snd_una - 1;
1002
1003         tcp_queue_rcv(sk, skb, sizeof(*th));
1004
1005         return size;
1006
1007 err_free:
1008         kfree_skb(skb);
1009 err:
1010         return -ENOMEM;
1011 }
1012
1013 int tcp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
1014                 size_t size)
1015 {
1016         struct iovec *iov;
1017         struct tcp_sock *tp = tcp_sk(sk);
1018         struct sk_buff *skb;
1019         int iovlen, flags, err, copied;
1020         int mss_now = 0, size_goal;
1021         bool sg;
1022         long timeo;
1023
1024         lock_sock(sk);
1025
1026         flags = msg->msg_flags;
1027         timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
1028
1029         /* Wait for a connection to finish. */
1030         if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT))
1031                 if ((err = sk_stream_wait_connect(sk, &timeo)) != 0)
1032                         goto out_err;
1033
1034         if (unlikely(tp->repair)) {
1035                 if (tp->repair_queue == TCP_RECV_QUEUE) {
1036                         copied = tcp_send_rcvq(sk, msg, size);
1037                         goto out;
1038                 }
1039
1040                 err = -EINVAL;
1041                 if (tp->repair_queue == TCP_NO_QUEUE)
1042                         goto out_err;
1043
1044                 /* 'common' sending to sendq */
1045         }
1046
1047         /* This should be in poll */
1048         clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
1049
1050         mss_now = tcp_send_mss(sk, &size_goal, flags);
1051
1052         /* Ok commence sending. */
1053         iovlen = msg->msg_iovlen;
1054         iov = msg->msg_iov;
1055         copied = 0;
1056
1057         err = -EPIPE;
1058         if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
1059                 goto out_err;
1060
1061         sg = !!(sk->sk_route_caps & NETIF_F_SG);
1062
1063         while (--iovlen >= 0) {
1064                 size_t seglen = iov->iov_len;
1065                 unsigned char __user *from = iov->iov_base;
1066
1067                 iov++;
1068
1069                 while (seglen > 0) {
1070                         int copy = 0;
1071                         int max = size_goal;
1072
1073                         skb = tcp_write_queue_tail(sk);
1074                         if (tcp_send_head(sk)) {
1075                                 if (skb->ip_summed == CHECKSUM_NONE)
1076                                         max = mss_now;
1077                                 copy = max - skb->len;
1078                         }
1079
1080                         if (copy <= 0) {
1081 new_segment:
1082                                 /* Allocate new segment. If the interface is SG,
1083                                  * allocate skb fitting to single page.
1084                                  */
1085                                 if (!sk_stream_memory_free(sk))
1086                                         goto wait_for_sndbuf;
1087
1088                                 skb = sk_stream_alloc_skb(sk,
1089                                                           select_size(sk, sg),
1090                                                           sk->sk_allocation);
1091                                 if (!skb)
1092                                         goto wait_for_memory;
1093
1094                                 /*
1095                                  * Check whether we can use HW checksum.
1096                                  */
1097                                 if (sk->sk_route_caps & NETIF_F_ALL_CSUM)
1098                                         skb->ip_summed = CHECKSUM_PARTIAL;
1099
1100                                 skb_entail(sk, skb);
1101                                 copy = size_goal;
1102                                 max = size_goal;
1103                         }
1104
1105                         /* Try to append data to the end of skb. */
1106                         if (copy > seglen)
1107                                 copy = seglen;
1108
1109                         /* Where to copy to? */
1110                         if (skb_availroom(skb) > 0) {
1111                                 /* We have some space in skb head. Superb! */
1112                                 copy = min_t(int, copy, skb_availroom(skb));
1113                                 err = skb_add_data_nocache(sk, skb, from, copy);
1114                                 if (err)
1115                                         goto do_fault;
1116                         } else {
1117                                 int merge = 0;
1118                                 int i = skb_shinfo(skb)->nr_frags;
1119                                 struct page *page = sk->sk_sndmsg_page;
1120                                 int off;
1121
1122                                 if (page && page_count(page) == 1)
1123                                         sk->sk_sndmsg_off = 0;
1124
1125                                 off = sk->sk_sndmsg_off;
1126
1127                                 if (skb_can_coalesce(skb, i, page, off) &&
1128                                     off != PAGE_SIZE) {
1129                                         /* We can extend the last page
1130                                          * fragment. */
1131                                         merge = 1;
1132                                 } else if (i == MAX_SKB_FRAGS || !sg) {
1133                                         /* Need to add new fragment and cannot
1134                                          * do this because interface is non-SG,
1135                                          * or because all the page slots are
1136                                          * busy. */
1137                                         tcp_mark_push(tp, skb);
1138                                         goto new_segment;
1139                                 } else if (page) {
1140                                         if (off == PAGE_SIZE) {
1141                                                 put_page(page);
1142                                                 sk->sk_sndmsg_page = page = NULL;
1143                                                 off = 0;
1144                                         }
1145                                 } else
1146                                         off = 0;
1147
1148                                 if (copy > PAGE_SIZE - off)
1149                                         copy = PAGE_SIZE - off;
1150
1151                                 if (!sk_wmem_schedule(sk, copy))
1152                                         goto wait_for_memory;
1153
1154                                 if (!page) {
1155                                         /* Allocate new cache page. */
1156                                         if (!(page = sk_stream_alloc_page(sk)))
1157                                                 goto wait_for_memory;
1158                                 }
1159
1160                                 /* Time to copy data. We are close to
1161                                  * the end! */
1162                                 err = skb_copy_to_page_nocache(sk, from, skb,
1163                                                                page, off, copy);
1164                                 if (err) {
1165                                         /* If this page was new, give it to the
1166                                          * socket so it does not get leaked.
1167                                          */
1168                                         if (!sk->sk_sndmsg_page) {
1169                                                 sk->sk_sndmsg_page = page;
1170                                                 sk->sk_sndmsg_off = 0;
1171                                         }
1172                                         goto do_error;
1173                                 }
1174
1175                                 /* Update the skb. */
1176                                 if (merge) {
1177                                         skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy);
1178                                 } else {
1179                                         skb_fill_page_desc(skb, i, page, off, copy);
1180                                         if (sk->sk_sndmsg_page) {
1181                                                 get_page(page);
1182                                         } else if (off + copy < PAGE_SIZE) {
1183                                                 get_page(page);
1184                                                 sk->sk_sndmsg_page = page;
1185                                         }
1186                                 }
1187
1188                                 sk->sk_sndmsg_off = off + copy;
1189                         }
1190
1191                         if (!copied)
1192                                 TCP_SKB_CB(skb)->tcp_flags &= ~TCPHDR_PSH;
1193
1194                         tp->write_seq += copy;
1195                         TCP_SKB_CB(skb)->end_seq += copy;
1196                         skb_shinfo(skb)->gso_segs = 0;
1197
1198                         from += copy;
1199                         copied += copy;
1200                         if ((seglen -= copy) == 0 && iovlen == 0)
1201                                 goto out;
1202
1203                         if (skb->len < max || (flags & MSG_OOB) || unlikely(tp->repair))
1204                                 continue;
1205
1206                         if (forced_push(tp)) {
1207                                 tcp_mark_push(tp, skb);
1208                                 __tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH);
1209                         } else if (skb == tcp_send_head(sk))
1210                                 tcp_push_one(sk, mss_now);
1211                         continue;
1212
1213 wait_for_sndbuf:
1214                         set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
1215 wait_for_memory:
1216                         if (copied && likely(!tp->repair))
1217                                 tcp_push(sk, flags & ~MSG_MORE, mss_now, TCP_NAGLE_PUSH);
1218
1219                         if ((err = sk_stream_wait_memory(sk, &timeo)) != 0)
1220                                 goto do_error;
1221
1222                         mss_now = tcp_send_mss(sk, &size_goal, flags);
1223                 }
1224         }
1225
1226 out:
1227         if (copied && likely(!tp->repair))
1228                 tcp_push(sk, flags, mss_now, tp->nonagle);
1229         release_sock(sk);
1230         return copied;
1231
1232 do_fault:
1233         if (!skb->len) {
1234                 tcp_unlink_write_queue(skb, sk);
1235                 /* It is the one place in all of TCP, except connection
1236                  * reset, where we can be unlinking the send_head.
1237                  */
1238                 tcp_check_send_head(sk, skb);
1239                 sk_wmem_free_skb(sk, skb);
1240         }
1241
1242 do_error:
1243         if (copied)
1244                 goto out;
1245 out_err:
1246         err = sk_stream_error(sk, flags, err);
1247         release_sock(sk);
1248         return err;
1249 }
1250 EXPORT_SYMBOL(tcp_sendmsg);
1251
1252 /*
1253  *      Handle reading urgent data. BSD has very simple semantics for
1254  *      this, no blocking and very strange errors 8)
1255  */
1256
1257 static int tcp_recv_urg(struct sock *sk, struct msghdr *msg, int len, int flags)
1258 {
1259         struct tcp_sock *tp = tcp_sk(sk);
1260
1261         /* No URG data to read. */
1262         if (sock_flag(sk, SOCK_URGINLINE) || !tp->urg_data ||
1263             tp->urg_data == TCP_URG_READ)
1264                 return -EINVAL; /* Yes this is right ! */
1265
1266         if (sk->sk_state == TCP_CLOSE && !sock_flag(sk, SOCK_DONE))
1267                 return -ENOTCONN;
1268
1269         if (tp->urg_data & TCP_URG_VALID) {
1270                 int err = 0;
1271                 char c = tp->urg_data;
1272
1273                 if (!(flags & MSG_PEEK))
1274                         tp->urg_data = TCP_URG_READ;
1275
1276                 /* Read urgent data. */
1277                 msg->msg_flags |= MSG_OOB;
1278
1279                 if (len > 0) {
1280                         if (!(flags & MSG_TRUNC))
1281                                 err = memcpy_toiovec(msg->msg_iov, &c, 1);
1282                         len = 1;
1283                 } else
1284                         msg->msg_flags |= MSG_TRUNC;
1285
1286                 return err ? -EFAULT : len;
1287         }
1288
1289         if (sk->sk_state == TCP_CLOSE || (sk->sk_shutdown & RCV_SHUTDOWN))
1290                 return 0;
1291
1292         /* Fixed the recv(..., MSG_OOB) behaviour.  BSD docs and
1293          * the available implementations agree in this case:
1294          * this call should never block, independent of the
1295          * blocking state of the socket.
1296          * Mike <pall@rz.uni-karlsruhe.de>
1297          */
1298         return -EAGAIN;
1299 }
1300
1301 static int tcp_peek_sndq(struct sock *sk, struct msghdr *msg, int len)
1302 {
1303         struct sk_buff *skb;
1304         int copied = 0, err = 0;
1305
1306         /* XXX -- need to support SO_PEEK_OFF */
1307
1308         skb_queue_walk(&sk->sk_write_queue, skb) {
1309                 err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, skb->len);
1310                 if (err)
1311                         break;
1312
1313                 copied += skb->len;
1314         }
1315
1316         return err ?: copied;
1317 }
1318
1319 /* Clean up the receive buffer for full frames taken by the user,
1320  * then send an ACK if necessary.  COPIED is the number of bytes
1321  * tcp_recvmsg has given to the user so far, it speeds up the
1322  * calculation of whether or not we must ACK for the sake of
1323  * a window update.
1324  */
1325 void tcp_cleanup_rbuf(struct sock *sk, int copied)
1326 {
1327         struct tcp_sock *tp = tcp_sk(sk);
1328         int time_to_ack = 0;
1329
1330         struct sk_buff *skb = skb_peek(&sk->sk_receive_queue);
1331
1332         WARN(skb && !before(tp->copied_seq, TCP_SKB_CB(skb)->end_seq),
1333              "cleanup rbuf bug: copied %X seq %X rcvnxt %X\n",
1334              tp->copied_seq, TCP_SKB_CB(skb)->end_seq, tp->rcv_nxt);
1335
1336         if (inet_csk_ack_scheduled(sk)) {
1337                 const struct inet_connection_sock *icsk = inet_csk(sk);
1338                    /* Delayed ACKs frequently hit locked sockets during bulk
1339                     * receive. */
1340                 if (icsk->icsk_ack.blocked ||
1341                     /* Once-per-two-segments ACK was not sent by tcp_input.c */
1342                     tp->rcv_nxt - tp->rcv_wup > icsk->icsk_ack.rcv_mss ||
1343                     /*
1344                      * If this read emptied read buffer, we send ACK, if
1345                      * connection is not bidirectional, user drained
1346                      * receive buffer and there was a small segment
1347                      * in queue.
1348                      */
1349                     (copied > 0 &&
1350                      ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED2) ||
1351                       ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED) &&
1352                        !icsk->icsk_ack.pingpong)) &&
1353                       !atomic_read(&sk->sk_rmem_alloc)))
1354                         time_to_ack = 1;
1355         }
1356
1357         /* We send an ACK if we can now advertise a non-zero window
1358          * which has been raised "significantly".
1359          *
1360          * Even if window raised up to infinity, do not send window open ACK
1361          * in states, where we will not receive more. It is useless.
1362          */
1363         if (copied > 0 && !time_to_ack && !(sk->sk_shutdown & RCV_SHUTDOWN)) {
1364                 __u32 rcv_window_now = tcp_receive_window(tp);
1365
1366                 /* Optimize, __tcp_select_window() is not cheap. */
1367                 if (2*rcv_window_now <= tp->window_clamp) {
1368                         __u32 new_window = __tcp_select_window(sk);
1369
1370                         /* Send ACK now, if this read freed lots of space
1371                          * in our buffer. Certainly, new_window is new window.
1372                          * We can advertise it now, if it is not less than current one.
1373                          * "Lots" means "at least twice" here.
1374                          */
1375                         if (new_window && new_window >= 2 * rcv_window_now)
1376                                 time_to_ack = 1;
1377                 }
1378         }
1379         if (time_to_ack)
1380                 tcp_send_ack(sk);
1381 }
1382
1383 static void tcp_prequeue_process(struct sock *sk)
1384 {
1385         struct sk_buff *skb;
1386         struct tcp_sock *tp = tcp_sk(sk);
1387
1388         NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPPREQUEUED);
1389
1390         /* RX process wants to run with disabled BHs, though it is not
1391          * necessary */
1392         local_bh_disable();
1393         while ((skb = __skb_dequeue(&tp->ucopy.prequeue)) != NULL)
1394                 sk_backlog_rcv(sk, skb);
1395         local_bh_enable();
1396
1397         /* Clear memory counter. */
1398         tp->ucopy.memory = 0;
1399 }
1400
1401 #ifdef CONFIG_NET_DMA
1402 static void tcp_service_net_dma(struct sock *sk, bool wait)
1403 {
1404         dma_cookie_t done, used;
1405         dma_cookie_t last_issued;
1406         struct tcp_sock *tp = tcp_sk(sk);
1407
1408         if (!tp->ucopy.dma_chan)
1409                 return;
1410
1411         last_issued = tp->ucopy.dma_cookie;
1412         dma_async_memcpy_issue_pending(tp->ucopy.dma_chan);
1413
1414         do {
1415                 if (dma_async_memcpy_complete(tp->ucopy.dma_chan,
1416                                               last_issued, &done,
1417                                               &used) == DMA_SUCCESS) {
1418                         /* Safe to free early-copied skbs now */
1419                         __skb_queue_purge(&sk->sk_async_wait_queue);
1420                         break;
1421                 } else {
1422                         struct sk_buff *skb;
1423                         while ((skb = skb_peek(&sk->sk_async_wait_queue)) &&
1424                                (dma_async_is_complete(skb->dma_cookie, done,
1425                                                       used) == DMA_SUCCESS)) {
1426                                 __skb_dequeue(&sk->sk_async_wait_queue);
1427                                 kfree_skb(skb);
1428                         }
1429                 }
1430         } while (wait);
1431 }
1432 #endif
1433
1434 static inline struct sk_buff *tcp_recv_skb(struct sock *sk, u32 seq, u32 *off)
1435 {
1436         struct sk_buff *skb;
1437         u32 offset;
1438
1439         skb_queue_walk(&sk->sk_receive_queue, skb) {
1440                 offset = seq - TCP_SKB_CB(skb)->seq;
1441                 if (tcp_hdr(skb)->syn)
1442                         offset--;
1443                 if (offset < skb->len || tcp_hdr(skb)->fin) {
1444                         *off = offset;
1445                         return skb;
1446                 }
1447         }
1448         return NULL;
1449 }
1450
1451 /*
1452  * This routine provides an alternative to tcp_recvmsg() for routines
1453  * that would like to handle copying from skbuffs directly in 'sendfile'
1454  * fashion.
1455  * Note:
1456  *      - It is assumed that the socket was locked by the caller.
1457  *      - The routine does not block.
1458  *      - At present, there is no support for reading OOB data
1459  *        or for 'peeking' the socket using this routine
1460  *        (although both would be easy to implement).
1461  */
1462 int tcp_read_sock(struct sock *sk, read_descriptor_t *desc,
1463                   sk_read_actor_t recv_actor)
1464 {
1465         struct sk_buff *skb;
1466         struct tcp_sock *tp = tcp_sk(sk);
1467         u32 seq = tp->copied_seq;
1468         u32 offset;
1469         int copied = 0;
1470
1471         if (sk->sk_state == TCP_LISTEN)
1472                 return -ENOTCONN;
1473         while ((skb = tcp_recv_skb(sk, seq, &offset)) != NULL) {
1474                 if (offset < skb->len) {
1475                         int used;
1476                         size_t len;
1477
1478                         len = skb->len - offset;
1479                         /* Stop reading if we hit a patch of urgent data */
1480                         if (tp->urg_data) {
1481                                 u32 urg_offset = tp->urg_seq - seq;
1482                                 if (urg_offset < len)
1483                                         len = urg_offset;
1484                                 if (!len)
1485                                         break;
1486                         }
1487                         used = recv_actor(desc, skb, offset, len);
1488                         if (used < 0) {
1489                                 if (!copied)
1490                                         copied = used;
1491                                 break;
1492                         } else if (used <= len) {
1493                                 seq += used;
1494                                 copied += used;
1495                                 offset += used;
1496                         }
1497                         /*
1498                          * If recv_actor drops the lock (e.g. TCP splice
1499                          * receive) the skb pointer might be invalid when
1500                          * getting here: tcp_collapse might have deleted it
1501                          * while aggregating skbs from the socket queue.
1502                          */
1503                         skb = tcp_recv_skb(sk, seq-1, &offset);
1504                         if (!skb || (offset+1 != skb->len))
1505                                 break;
1506                 }
1507                 if (tcp_hdr(skb)->fin) {
1508                         sk_eat_skb(sk, skb, 0);
1509                         ++seq;
1510                         break;
1511                 }
1512                 sk_eat_skb(sk, skb, 0);
1513                 if (!desc->count)
1514                         break;
1515                 tp->copied_seq = seq;
1516         }
1517         tp->copied_seq = seq;
1518
1519         tcp_rcv_space_adjust(sk);
1520
1521         /* Clean up data we have read: This will do ACK frames. */
1522         if (copied > 0)
1523                 tcp_cleanup_rbuf(sk, copied);
1524         return copied;
1525 }
1526 EXPORT_SYMBOL(tcp_read_sock);
1527
1528 /*
1529  *      This routine copies from a sock struct into the user buffer.
1530  *
1531  *      Technical note: in 2.3 we work on _locked_ socket, so that
1532  *      tricks with *seq access order and skb->users are not required.
1533  *      Probably, code can be easily improved even more.
1534  */
1535
1536 int tcp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
1537                 size_t len, int nonblock, int flags, int *addr_len)
1538 {
1539         struct tcp_sock *tp = tcp_sk(sk);
1540         int copied = 0;
1541         u32 peek_seq;
1542         u32 *seq;
1543         unsigned long used;
1544         int err;
1545         int target;             /* Read at least this many bytes */
1546         long timeo;
1547         struct task_struct *user_recv = NULL;
1548         int copied_early = 0;
1549         struct sk_buff *skb;
1550         u32 urg_hole = 0;
1551
1552         lock_sock(sk);
1553
1554         err = -ENOTCONN;
1555         if (sk->sk_state == TCP_LISTEN)
1556                 goto out;
1557
1558         timeo = sock_rcvtimeo(sk, nonblock);
1559
1560         /* Urgent data needs to be handled specially. */
1561         if (flags & MSG_OOB)
1562                 goto recv_urg;
1563
1564         if (unlikely(tp->repair)) {
1565                 err = -EPERM;
1566                 if (!(flags & MSG_PEEK))
1567                         goto out;
1568
1569                 if (tp->repair_queue == TCP_SEND_QUEUE)
1570                         goto recv_sndq;
1571
1572                 err = -EINVAL;
1573                 if (tp->repair_queue == TCP_NO_QUEUE)
1574                         goto out;
1575
1576                 /* 'common' recv queue MSG_PEEK-ing */
1577         }
1578
1579         seq = &tp->copied_seq;
1580         if (flags & MSG_PEEK) {
1581                 peek_seq = tp->copied_seq;
1582                 seq = &peek_seq;
1583         }
1584
1585         target = sock_rcvlowat(sk, flags & MSG_WAITALL, len);
1586
1587 #ifdef CONFIG_NET_DMA
1588         tp->ucopy.dma_chan = NULL;
1589         preempt_disable();
1590         skb = skb_peek_tail(&sk->sk_receive_queue);
1591         {
1592                 int available = 0;
1593
1594                 if (skb)
1595                         available = TCP_SKB_CB(skb)->seq + skb->len - (*seq);
1596                 if ((available < target) &&
1597                     (len > sysctl_tcp_dma_copybreak) && !(flags & MSG_PEEK) &&
1598                     !sysctl_tcp_low_latency &&
1599                     net_dma_find_channel()) {
1600                         preempt_enable_no_resched();
1601                         tp->ucopy.pinned_list =
1602                                         dma_pin_iovec_pages(msg->msg_iov, len);
1603                 } else {
1604                         preempt_enable_no_resched();
1605                 }
1606         }
1607 #endif
1608
1609         do {
1610                 u32 offset;
1611
1612                 /* Are we at urgent data? Stop if we have read anything or have SIGURG pending. */
1613                 if (tp->urg_data && tp->urg_seq == *seq) {
1614                         if (copied)
1615                                 break;
1616                         if (signal_pending(current)) {
1617                                 copied = timeo ? sock_intr_errno(timeo) : -EAGAIN;
1618                                 break;
1619                         }
1620                 }
1621
1622                 /* Next get a buffer. */
1623
1624                 skb_queue_walk(&sk->sk_receive_queue, skb) {
1625                         /* Now that we have two receive queues this
1626                          * shouldn't happen.
1627                          */
1628                         if (WARN(before(*seq, TCP_SKB_CB(skb)->seq),
1629                                  "recvmsg bug: copied %X seq %X rcvnxt %X fl %X\n",
1630                                  *seq, TCP_SKB_CB(skb)->seq, tp->rcv_nxt,
1631                                  flags))
1632                                 break;
1633
1634                         offset = *seq - TCP_SKB_CB(skb)->seq;
1635                         if (tcp_hdr(skb)->syn)
1636                                 offset--;
1637                         if (offset < skb->len)
1638                                 goto found_ok_skb;
1639                         if (tcp_hdr(skb)->fin)
1640                                 goto found_fin_ok;
1641                         WARN(!(flags & MSG_PEEK),
1642                              "recvmsg bug 2: copied %X seq %X rcvnxt %X fl %X\n",
1643                              *seq, TCP_SKB_CB(skb)->seq, tp->rcv_nxt, flags);
1644                 }
1645
1646                 /* Well, if we have backlog, try to process it now yet. */
1647
1648                 if (copied >= target && !sk->sk_backlog.tail)
1649                         break;
1650
1651                 if (copied) {
1652                         if (sk->sk_err ||
1653                             sk->sk_state == TCP_CLOSE ||
1654                             (sk->sk_shutdown & RCV_SHUTDOWN) ||
1655                             !timeo ||
1656                             signal_pending(current))
1657                                 break;
1658                 } else {
1659                         if (sock_flag(sk, SOCK_DONE))
1660                                 break;
1661
1662                         if (sk->sk_err) {
1663                                 copied = sock_error(sk);
1664                                 break;
1665                         }
1666
1667                         if (sk->sk_shutdown & RCV_SHUTDOWN)
1668                                 break;
1669
1670                         if (sk->sk_state == TCP_CLOSE) {
1671                                 if (!sock_flag(sk, SOCK_DONE)) {
1672                                         /* This occurs when user tries to read
1673                                          * from never connected socket.
1674                                          */
1675                                         copied = -ENOTCONN;
1676                                         break;
1677                                 }
1678                                 break;
1679                         }
1680
1681                         if (!timeo) {
1682                                 copied = -EAGAIN;
1683                                 break;
1684                         }
1685
1686                         if (signal_pending(current)) {
1687                                 copied = sock_intr_errno(timeo);
1688                                 break;
1689                         }
1690                 }
1691
1692                 tcp_cleanup_rbuf(sk, copied);
1693
1694                 if (!sysctl_tcp_low_latency && tp->ucopy.task == user_recv) {
1695                         /* Install new reader */
1696                         if (!user_recv && !(flags & (MSG_TRUNC | MSG_PEEK))) {
1697                                 user_recv = current;
1698                                 tp->ucopy.task = user_recv;
1699                                 tp->ucopy.iov = msg->msg_iov;
1700                         }
1701
1702                         tp->ucopy.len = len;
1703
1704                         WARN_ON(tp->copied_seq != tp->rcv_nxt &&
1705                                 !(flags & (MSG_PEEK | MSG_TRUNC)));
1706
1707                         /* Ugly... If prequeue is not empty, we have to
1708                          * process it before releasing socket, otherwise
1709                          * order will be broken at second iteration.
1710                          * More elegant solution is required!!!
1711                          *
1712                          * Look: we have the following (pseudo)queues:
1713                          *
1714                          * 1. packets in flight
1715                          * 2. backlog
1716                          * 3. prequeue
1717                          * 4. receive_queue
1718                          *
1719                          * Each queue can be processed only if the next ones
1720                          * are empty. At this point we have empty receive_queue.
1721                          * But prequeue _can_ be not empty after 2nd iteration,
1722                          * when we jumped to start of loop because backlog
1723                          * processing added something to receive_queue.
1724                          * We cannot release_sock(), because backlog contains
1725                          * packets arrived _after_ prequeued ones.
1726                          *
1727                          * Shortly, algorithm is clear --- to process all
1728                          * the queues in order. We could make it more directly,
1729                          * requeueing packets from backlog to prequeue, if
1730                          * is not empty. It is more elegant, but eats cycles,
1731                          * unfortunately.
1732                          */
1733                         if (!skb_queue_empty(&tp->ucopy.prequeue))
1734                                 goto do_prequeue;
1735
1736                         /* __ Set realtime policy in scheduler __ */
1737                 }
1738
1739 #ifdef CONFIG_NET_DMA
1740                 if (tp->ucopy.dma_chan)
1741                         dma_async_memcpy_issue_pending(tp->ucopy.dma_chan);
1742 #endif
1743                 if (copied >= target) {
1744                         /* Do not sleep, just process backlog. */
1745                         release_sock(sk);
1746                         lock_sock(sk);
1747                 } else
1748                         sk_wait_data(sk, &timeo);
1749
1750 #ifdef CONFIG_NET_DMA
1751                 tcp_service_net_dma(sk, false);  /* Don't block */
1752                 tp->ucopy.wakeup = 0;
1753 #endif
1754
1755                 if (user_recv) {
1756                         int chunk;
1757
1758                         /* __ Restore normal policy in scheduler __ */
1759
1760                         if ((chunk = len - tp->ucopy.len) != 0) {
1761                                 NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMBACKLOG, chunk);
1762                                 len -= chunk;
1763                                 copied += chunk;
1764                         }
1765
1766                         if (tp->rcv_nxt == tp->copied_seq &&
1767                             !skb_queue_empty(&tp->ucopy.prequeue)) {
1768 do_prequeue:
1769                                 tcp_prequeue_process(sk);
1770
1771                                 if ((chunk = len - tp->ucopy.len) != 0) {
1772                                         NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
1773                                         len -= chunk;
1774                                         copied += chunk;
1775                                 }
1776                         }
1777                 }
1778                 if ((flags & MSG_PEEK) &&
1779                     (peek_seq - copied - urg_hole != tp->copied_seq)) {
1780                         if (net_ratelimit())
1781                                 printk(KERN_DEBUG "TCP(%s:%d): Application bug, race in MSG_PEEK.\n",
1782                                        current->comm, task_pid_nr(current));
1783                         peek_seq = tp->copied_seq;
1784                 }
1785                 continue;
1786
1787         found_ok_skb:
1788                 /* Ok so how much can we use? */
1789                 used = skb->len - offset;
1790                 if (len < used)
1791                         used = len;
1792
1793                 /* Do we have urgent data here? */
1794                 if (tp->urg_data) {
1795                         u32 urg_offset = tp->urg_seq - *seq;
1796                         if (urg_offset < used) {
1797                                 if (!urg_offset) {
1798                                         if (!sock_flag(sk, SOCK_URGINLINE)) {
1799                                                 ++*seq;
1800                                                 urg_hole++;
1801                                                 offset++;
1802                                                 used--;
1803                                                 if (!used)
1804                                                         goto skip_copy;
1805                                         }
1806                                 } else
1807                                         used = urg_offset;
1808                         }
1809                 }
1810
1811                 if (!(flags & MSG_TRUNC)) {
1812 #ifdef CONFIG_NET_DMA
1813                         if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list)
1814                                 tp->ucopy.dma_chan = net_dma_find_channel();
1815
1816                         if (tp->ucopy.dma_chan) {
1817                                 tp->ucopy.dma_cookie = dma_skb_copy_datagram_iovec(
1818                                         tp->ucopy.dma_chan, skb, offset,
1819                                         msg->msg_iov, used,
1820                                         tp->ucopy.pinned_list);
1821
1822                                 if (tp->ucopy.dma_cookie < 0) {
1823
1824                                         pr_alert("%s: dma_cookie < 0\n",
1825                                                  __func__);
1826
1827                                         /* Exception. Bailout! */
1828                                         if (!copied)
1829                                                 copied = -EFAULT;
1830                                         break;
1831                                 }
1832
1833                                 dma_async_memcpy_issue_pending(tp->ucopy.dma_chan);
1834
1835                                 if ((offset + used) == skb->len)
1836                                         copied_early = 1;
1837
1838                         } else
1839 #endif
1840                         {
1841                                 err = skb_copy_datagram_iovec(skb, offset,
1842                                                 msg->msg_iov, used);
1843                                 if (err) {
1844                                         /* Exception. Bailout! */
1845                                         if (!copied)
1846                                                 copied = -EFAULT;
1847                                         break;
1848                                 }
1849                         }
1850                 }
1851
1852                 *seq += used;
1853                 copied += used;
1854                 len -= used;
1855
1856                 tcp_rcv_space_adjust(sk);
1857
1858 skip_copy:
1859                 if (tp->urg_data && after(tp->copied_seq, tp->urg_seq)) {
1860                         tp->urg_data = 0;
1861                         tcp_fast_path_check(sk);
1862                 }
1863                 if (used + offset < skb->len)
1864                         continue;
1865
1866                 if (tcp_hdr(skb)->fin)
1867                         goto found_fin_ok;
1868                 if (!(flags & MSG_PEEK)) {
1869                         sk_eat_skb(sk, skb, copied_early);
1870                         copied_early = 0;
1871                 }
1872                 continue;
1873
1874         found_fin_ok:
1875                 /* Process the FIN. */
1876                 ++*seq;
1877                 if (!(flags & MSG_PEEK)) {
1878                         sk_eat_skb(sk, skb, copied_early);
1879                         copied_early = 0;
1880                 }
1881                 break;
1882         } while (len > 0);
1883
1884         if (user_recv) {
1885                 if (!skb_queue_empty(&tp->ucopy.prequeue)) {
1886                         int chunk;
1887
1888                         tp->ucopy.len = copied > 0 ? len : 0;
1889
1890                         tcp_prequeue_process(sk);
1891
1892                         if (copied > 0 && (chunk = len - tp->ucopy.len) != 0) {
1893                                 NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
1894                                 len -= chunk;
1895                                 copied += chunk;
1896                         }
1897                 }
1898
1899                 tp->ucopy.task = NULL;
1900                 tp->ucopy.len = 0;
1901         }
1902
1903 #ifdef CONFIG_NET_DMA
1904         tcp_service_net_dma(sk, true);  /* Wait for queue to drain */
1905         tp->ucopy.dma_chan = NULL;
1906
1907         if (tp->ucopy.pinned_list) {
1908                 dma_unpin_iovec_pages(tp->ucopy.pinned_list);
1909                 tp->ucopy.pinned_list = NULL;
1910         }
1911 #endif
1912
1913         /* According to UNIX98, msg_name/msg_namelen are ignored
1914          * on connected socket. I was just happy when found this 8) --ANK
1915          */
1916
1917         /* Clean up data we have read: This will do ACK frames. */
1918         tcp_cleanup_rbuf(sk, copied);
1919
1920         release_sock(sk);
1921         return copied;
1922
1923 out:
1924         release_sock(sk);
1925         return err;
1926
1927 recv_urg:
1928         err = tcp_recv_urg(sk, msg, len, flags);
1929         goto out;
1930
1931 recv_sndq:
1932         err = tcp_peek_sndq(sk, msg, len);
1933         goto out;
1934 }
1935 EXPORT_SYMBOL(tcp_recvmsg);
1936
1937 void tcp_set_state(struct sock *sk, int state)
1938 {
1939         int oldstate = sk->sk_state;
1940
1941         switch (state) {
1942         case TCP_ESTABLISHED:
1943                 if (oldstate != TCP_ESTABLISHED)
1944                         TCP_INC_STATS(sock_net(sk), TCP_MIB_CURRESTAB);
1945                 break;
1946
1947         case TCP_CLOSE:
1948                 if (oldstate == TCP_CLOSE_WAIT || oldstate == TCP_ESTABLISHED)
1949                         TCP_INC_STATS(sock_net(sk), TCP_MIB_ESTABRESETS);
1950
1951                 sk->sk_prot->unhash(sk);
1952                 if (inet_csk(sk)->icsk_bind_hash &&
1953                     !(sk->sk_userlocks & SOCK_BINDPORT_LOCK))
1954                         inet_put_port(sk);
1955                 /* fall through */
1956         default:
1957                 if (oldstate == TCP_ESTABLISHED)
1958                         TCP_DEC_STATS(sock_net(sk), TCP_MIB_CURRESTAB);
1959         }
1960
1961         /* Change state AFTER socket is unhashed to avoid closed
1962          * socket sitting in hash tables.
1963          */
1964         sk->sk_state = state;
1965
1966 #ifdef STATE_TRACE
1967         SOCK_DEBUG(sk, "TCP sk=%p, State %s -> %s\n", sk, statename[oldstate], statename[state]);
1968 #endif
1969 }
1970 EXPORT_SYMBOL_GPL(tcp_set_state);
1971
1972 /*
1973  *      State processing on a close. This implements the state shift for
1974  *      sending our FIN frame. Note that we only send a FIN for some
1975  *      states. A shutdown() may have already sent the FIN, or we may be
1976  *      closed.
1977  */
1978
1979 static const unsigned char new_state[16] = {
1980   /* current state:        new state:      action:      */
1981   /* (Invalid)          */ TCP_CLOSE,
1982   /* TCP_ESTABLISHED    */ TCP_FIN_WAIT1 | TCP_ACTION_FIN,
1983   /* TCP_SYN_SENT       */ TCP_CLOSE,
1984   /* TCP_SYN_RECV       */ TCP_FIN_WAIT1 | TCP_ACTION_FIN,
1985   /* TCP_FIN_WAIT1      */ TCP_FIN_WAIT1,
1986   /* TCP_FIN_WAIT2      */ TCP_FIN_WAIT2,
1987   /* TCP_TIME_WAIT      */ TCP_CLOSE,
1988   /* TCP_CLOSE          */ TCP_CLOSE,
1989   /* TCP_CLOSE_WAIT     */ TCP_LAST_ACK  | TCP_ACTION_FIN,
1990   /* TCP_LAST_ACK       */ TCP_LAST_ACK,
1991   /* TCP_LISTEN         */ TCP_CLOSE,
1992   /* TCP_CLOSING        */ TCP_CLOSING,
1993 };
1994
1995 static int tcp_close_state(struct sock *sk)
1996 {
1997         int next = (int)new_state[sk->sk_state];
1998         int ns = next & TCP_STATE_MASK;
1999
2000         tcp_set_state(sk, ns);
2001
2002         return next & TCP_ACTION_FIN;
2003 }
2004
2005 /*
2006  *      Shutdown the sending side of a connection. Much like close except
2007  *      that we don't receive shut down or sock_set_flag(sk, SOCK_DEAD).
2008  */
2009
2010 void tcp_shutdown(struct sock *sk, int how)
2011 {
2012         /*      We need to grab some memory, and put together a FIN,
2013          *      and then put it into the queue to be sent.
2014          *              Tim MacKenzie(tym@dibbler.cs.monash.edu.au) 4 Dec '92.
2015          */
2016         if (!(how & SEND_SHUTDOWN))
2017                 return;
2018
2019         /* If we've already sent a FIN, or it's a closed state, skip this. */
2020         if ((1 << sk->sk_state) &
2021             (TCPF_ESTABLISHED | TCPF_SYN_SENT |
2022              TCPF_SYN_RECV | TCPF_CLOSE_WAIT)) {
2023                 /* Clear out any half completed packets.  FIN if needed. */
2024                 if (tcp_close_state(sk))
2025                         tcp_send_fin(sk);
2026         }
2027 }
2028 EXPORT_SYMBOL(tcp_shutdown);
2029
2030 bool tcp_check_oom(struct sock *sk, int shift)
2031 {
2032         bool too_many_orphans, out_of_socket_memory;
2033
2034         too_many_orphans = tcp_too_many_orphans(sk, shift);
2035         out_of_socket_memory = tcp_out_of_memory(sk);
2036
2037         if (too_many_orphans && net_ratelimit())
2038                 pr_info("too many orphaned sockets\n");
2039         if (out_of_socket_memory && net_ratelimit())
2040                 pr_info("out of memory -- consider tuning tcp_mem\n");
2041         return too_many_orphans || out_of_socket_memory;
2042 }
2043
2044 void tcp_close(struct sock *sk, long timeout)
2045 {
2046         struct sk_buff *skb;
2047         int data_was_unread = 0;
2048         int state;
2049
2050         lock_sock(sk);
2051         sk->sk_shutdown = SHUTDOWN_MASK;
2052
2053         if (sk->sk_state == TCP_LISTEN) {
2054                 tcp_set_state(sk, TCP_CLOSE);
2055
2056                 /* Special case. */
2057                 inet_csk_listen_stop(sk);
2058
2059                 goto adjudge_to_death;
2060         }
2061
2062         /*  We need to flush the recv. buffs.  We do this only on the
2063          *  descriptor close, not protocol-sourced closes, because the
2064          *  reader process may not have drained the data yet!
2065          */
2066         while ((skb = __skb_dequeue(&sk->sk_receive_queue)) != NULL) {
2067                 u32 len = TCP_SKB_CB(skb)->end_seq - TCP_SKB_CB(skb)->seq -
2068                           tcp_hdr(skb)->fin;
2069                 data_was_unread += len;
2070                 __kfree_skb(skb);
2071         }
2072
2073         sk_mem_reclaim(sk);
2074
2075         /* If socket has been already reset (e.g. in tcp_reset()) - kill it. */
2076         if (sk->sk_state == TCP_CLOSE)
2077                 goto adjudge_to_death;
2078
2079         /* As outlined in RFC 2525, section 2.17, we send a RST here because
2080          * data was lost. To witness the awful effects of the old behavior of
2081          * always doing a FIN, run an older 2.1.x kernel or 2.0.x, start a bulk
2082          * GET in an FTP client, suspend the process, wait for the client to
2083          * advertise a zero window, then kill -9 the FTP client, wheee...
2084          * Note: timeout is always zero in such a case.
2085          */
2086         if (unlikely(tcp_sk(sk)->repair)) {
2087                 sk->sk_prot->disconnect(sk, 0);
2088         } else if (data_was_unread) {
2089                 /* Unread data was tossed, zap the connection. */
2090                 NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPABORTONCLOSE);
2091                 tcp_set_state(sk, TCP_CLOSE);
2092                 tcp_send_active_reset(sk, sk->sk_allocation);
2093         } else if (sock_flag(sk, SOCK_LINGER) && !sk->sk_lingertime) {
2094                 /* Check zero linger _after_ checking for unread data. */
2095                 sk->sk_prot->disconnect(sk, 0);
2096                 NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPABORTONDATA);
2097         } else if (tcp_close_state(sk)) {
2098                 /* We FIN if the application ate all the data before
2099                  * zapping the connection.
2100                  */
2101
2102                 /* RED-PEN. Formally speaking, we have broken TCP state
2103                  * machine. State transitions:
2104                  *
2105                  * TCP_ESTABLISHED -> TCP_FIN_WAIT1
2106                  * TCP_SYN_RECV -> TCP_FIN_WAIT1 (forget it, it's impossible)
2107                  * TCP_CLOSE_WAIT -> TCP_LAST_ACK
2108                  *
2109                  * are legal only when FIN has been sent (i.e. in window),
2110                  * rather than queued out of window. Purists blame.
2111                  *
2112                  * F.e. "RFC state" is ESTABLISHED,
2113                  * if Linux state is FIN-WAIT-1, but FIN is still not sent.
2114                  *
2115                  * The visible declinations are that sometimes
2116                  * we enter time-wait state, when it is not required really
2117                  * (harmless), do not send active resets, when they are
2118                  * required by specs (TCP_ESTABLISHED, TCP_CLOSE_WAIT, when
2119                  * they look as CLOSING or LAST_ACK for Linux)
2120                  * Probably, I missed some more holelets.
2121                  *                                              --ANK
2122                  */
2123                 tcp_send_fin(sk);
2124         }
2125
2126         sk_stream_wait_close(sk, timeout);
2127
2128 adjudge_to_death:
2129         state = sk->sk_state;
2130         sock_hold(sk);
2131         sock_orphan(sk);
2132
2133         /* It is the last release_sock in its life. It will remove backlog. */
2134         release_sock(sk);
2135
2136
2137         /* Now socket is owned by kernel and we acquire BH lock
2138            to finish close. No need to check for user refs.
2139          */
2140         local_bh_disable();
2141         bh_lock_sock(sk);
2142         WARN_ON(sock_owned_by_user(sk));
2143
2144         percpu_counter_inc(sk->sk_prot->orphan_count);
2145
2146         /* Have we already been destroyed by a softirq or backlog? */
2147         if (state != TCP_CLOSE && sk->sk_state == TCP_CLOSE)
2148                 goto out;
2149
2150         /*      This is a (useful) BSD violating of the RFC. There is a
2151          *      problem with TCP as specified in that the other end could
2152          *      keep a socket open forever with no application left this end.
2153          *      We use a 3 minute timeout (about the same as BSD) then kill
2154          *      our end. If they send after that then tough - BUT: long enough
2155          *      that we won't make the old 4*rto = almost no time - whoops
2156          *      reset mistake.
2157          *
2158          *      Nope, it was not mistake. It is really desired behaviour
2159          *      f.e. on http servers, when such sockets are useless, but
2160          *      consume significant resources. Let's do it with special
2161          *      linger2 option.                                 --ANK
2162          */
2163
2164         if (sk->sk_state == TCP_FIN_WAIT2) {
2165                 struct tcp_sock *tp = tcp_sk(sk);
2166                 if (tp->linger2 < 0) {
2167                         tcp_set_state(sk, TCP_CLOSE);
2168                         tcp_send_active_reset(sk, GFP_ATOMIC);
2169                         NET_INC_STATS_BH(sock_net(sk),
2170                                         LINUX_MIB_TCPABORTONLINGER);
2171                 } else {
2172                         const int tmo = tcp_fin_time(sk);
2173
2174                         if (tmo > TCP_TIMEWAIT_LEN) {
2175                                 inet_csk_reset_keepalive_timer(sk,
2176                                                 tmo - TCP_TIMEWAIT_LEN);
2177                         } else {
2178                                 tcp_time_wait(sk, TCP_FIN_WAIT2, tmo);
2179                                 goto out;
2180                         }
2181                 }
2182         }
2183         if (sk->sk_state != TCP_CLOSE) {
2184                 sk_mem_reclaim(sk);
2185                 if (tcp_check_oom(sk, 0)) {
2186                         tcp_set_state(sk, TCP_CLOSE);
2187                         tcp_send_active_reset(sk, GFP_ATOMIC);
2188                         NET_INC_STATS_BH(sock_net(sk),
2189                                         LINUX_MIB_TCPABORTONMEMORY);
2190                 }
2191         }
2192
2193         if (sk->sk_state == TCP_CLOSE)
2194                 inet_csk_destroy_sock(sk);
2195         /* Otherwise, socket is reprieved until protocol close. */
2196
2197 out:
2198         bh_unlock_sock(sk);
2199         local_bh_enable();
2200         sock_put(sk);
2201 }
2202 EXPORT_SYMBOL(tcp_close);
2203
2204 /* These states need RST on ABORT according to RFC793 */
2205
2206 static inline int tcp_need_reset(int state)
2207 {
2208         return (1 << state) &
2209                (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT | TCPF_FIN_WAIT1 |
2210                 TCPF_FIN_WAIT2 | TCPF_SYN_RECV);
2211 }
2212
2213 int tcp_disconnect(struct sock *sk, int flags)
2214 {
2215         struct inet_sock *inet = inet_sk(sk);
2216         struct inet_connection_sock *icsk = inet_csk(sk);
2217         struct tcp_sock *tp = tcp_sk(sk);
2218         int err = 0;
2219         int old_state = sk->sk_state;
2220
2221         if (old_state != TCP_CLOSE)
2222                 tcp_set_state(sk, TCP_CLOSE);
2223
2224         /* ABORT function of RFC793 */
2225         if (old_state == TCP_LISTEN) {
2226                 inet_csk_listen_stop(sk);
2227         } else if (unlikely(tp->repair)) {
2228                 sk->sk_err = ECONNABORTED;
2229         } else if (tcp_need_reset(old_state) ||
2230                    (tp->snd_nxt != tp->write_seq &&
2231                     (1 << old_state) & (TCPF_CLOSING | TCPF_LAST_ACK))) {
2232                 /* The last check adjusts for discrepancy of Linux wrt. RFC
2233                  * states
2234                  */
2235                 tcp_send_active_reset(sk, gfp_any());
2236                 sk->sk_err = ECONNRESET;
2237         } else if (old_state == TCP_SYN_SENT)
2238                 sk->sk_err = ECONNRESET;
2239
2240         tcp_clear_xmit_timers(sk);
2241         __skb_queue_purge(&sk->sk_receive_queue);
2242         tcp_write_queue_purge(sk);
2243         __skb_queue_purge(&tp->out_of_order_queue);
2244 #ifdef CONFIG_NET_DMA
2245         __skb_queue_purge(&sk->sk_async_wait_queue);
2246 #endif
2247
2248         inet->inet_dport = 0;
2249
2250         if (!(sk->sk_userlocks & SOCK_BINDADDR_LOCK))
2251                 inet_reset_saddr(sk);
2252
2253         sk->sk_shutdown = 0;
2254         sock_reset_flag(sk, SOCK_DONE);
2255         tp->srtt = 0;
2256         if ((tp->write_seq += tp->max_window + 2) == 0)
2257                 tp->write_seq = 1;
2258         icsk->icsk_backoff = 0;
2259         tp->snd_cwnd = 2;
2260         icsk->icsk_probes_out = 0;
2261         tp->packets_out = 0;
2262         tp->snd_ssthresh = TCP_INFINITE_SSTHRESH;
2263         tp->snd_cwnd_cnt = 0;
2264         tp->bytes_acked = 0;
2265         tp->window_clamp = 0;
2266         tcp_set_ca_state(sk, TCP_CA_Open);
2267         tcp_clear_retrans(tp);
2268         inet_csk_delack_init(sk);
2269         tcp_init_send_head(sk);
2270         memset(&tp->rx_opt, 0, sizeof(tp->rx_opt));
2271         __sk_dst_reset(sk);
2272
2273         WARN_ON(inet->inet_num && !icsk->icsk_bind_hash);
2274
2275         sk->sk_error_report(sk);
2276         return err;
2277 }
2278 EXPORT_SYMBOL(tcp_disconnect);
2279
2280 static inline int tcp_can_repair_sock(struct sock *sk)
2281 {
2282         return capable(CAP_NET_ADMIN) &&
2283                 ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_ESTABLISHED));
2284 }
2285
2286 static int tcp_repair_options_est(struct tcp_sock *tp,
2287                 struct tcp_repair_opt __user *optbuf, unsigned int len)
2288 {
2289         struct tcp_repair_opt opt;
2290
2291         while (len >= sizeof(opt)) {
2292                 if (copy_from_user(&opt, optbuf, sizeof(opt)))
2293                         return -EFAULT;
2294
2295                 optbuf++;
2296                 len -= sizeof(opt);
2297
2298                 switch (opt.opt_code) {
2299                 case TCPOPT_MSS:
2300                         tp->rx_opt.mss_clamp = opt.opt_val;
2301                         break;
2302                 case TCPOPT_WINDOW:
2303                         if (opt.opt_val > 14)
2304                                 return -EFBIG;
2305
2306                         tp->rx_opt.snd_wscale = opt.opt_val;
2307                         break;
2308                 case TCPOPT_SACK_PERM:
2309                         if (opt.opt_val != 0)
2310                                 return -EINVAL;
2311
2312                         tp->rx_opt.sack_ok |= TCP_SACK_SEEN;
2313                         if (sysctl_tcp_fack)
2314                                 tcp_enable_fack(tp);
2315                         break;
2316                 case TCPOPT_TIMESTAMP:
2317                         if (opt.opt_val != 0)
2318                                 return -EINVAL;
2319
2320                         tp->rx_opt.tstamp_ok = 1;
2321                         break;
2322                 }
2323         }
2324
2325         return 0;
2326 }
2327
2328 /*
2329  *      Socket option code for TCP.
2330  */
2331 static int do_tcp_setsockopt(struct sock *sk, int level,
2332                 int optname, char __user *optval, unsigned int optlen)
2333 {
2334         struct tcp_sock *tp = tcp_sk(sk);
2335         struct inet_connection_sock *icsk = inet_csk(sk);
2336         int val;
2337         int err = 0;
2338
2339         /* These are data/string values, all the others are ints */
2340         switch (optname) {
2341         case TCP_CONGESTION: {
2342                 char name[TCP_CA_NAME_MAX];
2343
2344                 if (optlen < 1)
2345                         return -EINVAL;
2346
2347                 val = strncpy_from_user(name, optval,
2348                                         min_t(long, TCP_CA_NAME_MAX-1, optlen));
2349                 if (val < 0)
2350                         return -EFAULT;
2351                 name[val] = 0;
2352
2353                 lock_sock(sk);
2354                 err = tcp_set_congestion_control(sk, name);
2355                 release_sock(sk);
2356                 return err;
2357         }
2358         case TCP_COOKIE_TRANSACTIONS: {
2359                 struct tcp_cookie_transactions ctd;
2360                 struct tcp_cookie_values *cvp = NULL;
2361
2362                 if (sizeof(ctd) > optlen)
2363                         return -EINVAL;
2364                 if (copy_from_user(&ctd, optval, sizeof(ctd)))
2365                         return -EFAULT;
2366
2367                 if (ctd.tcpct_used > sizeof(ctd.tcpct_value) ||
2368                     ctd.tcpct_s_data_desired > TCP_MSS_DESIRED)
2369                         return -EINVAL;
2370
2371                 if (ctd.tcpct_cookie_desired == 0) {
2372                         /* default to global value */
2373                 } else if ((0x1 & ctd.tcpct_cookie_desired) ||
2374                            ctd.tcpct_cookie_desired > TCP_COOKIE_MAX ||
2375                            ctd.tcpct_cookie_desired < TCP_COOKIE_MIN) {
2376                         return -EINVAL;
2377                 }
2378
2379                 if (TCP_COOKIE_OUT_NEVER & ctd.tcpct_flags) {
2380                         /* Supercedes all other values */
2381                         lock_sock(sk);
2382                         if (tp->cookie_values != NULL) {
2383                                 kref_put(&tp->cookie_values->kref,
2384                                          tcp_cookie_values_release);
2385                                 tp->cookie_values = NULL;
2386                         }
2387                         tp->rx_opt.cookie_in_always = 0; /* false */
2388                         tp->rx_opt.cookie_out_never = 1; /* true */
2389                         release_sock(sk);
2390                         return err;
2391                 }
2392
2393                 /* Allocate ancillary memory before locking.
2394                  */
2395                 if (ctd.tcpct_used > 0 ||
2396                     (tp->cookie_values == NULL &&
2397                      (sysctl_tcp_cookie_size > 0 ||
2398                       ctd.tcpct_cookie_desired > 0 ||
2399                       ctd.tcpct_s_data_desired > 0))) {
2400                         cvp = kzalloc(sizeof(*cvp) + ctd.tcpct_used,
2401                                       GFP_KERNEL);
2402                         if (cvp == NULL)
2403                                 return -ENOMEM;
2404
2405                         kref_init(&cvp->kref);
2406                 }
2407                 lock_sock(sk);
2408                 tp->rx_opt.cookie_in_always =
2409                         (TCP_COOKIE_IN_ALWAYS & ctd.tcpct_flags);
2410                 tp->rx_opt.cookie_out_never = 0; /* false */
2411
2412                 if (tp->cookie_values != NULL) {
2413                         if (cvp != NULL) {
2414                                 /* Changed values are recorded by a changed
2415                                  * pointer, ensuring the cookie will differ,
2416                                  * without separately hashing each value later.
2417                                  */
2418                                 kref_put(&tp->cookie_values->kref,
2419                                          tcp_cookie_values_release);
2420                         } else {
2421                                 cvp = tp->cookie_values;
2422                         }
2423                 }
2424
2425                 if (cvp != NULL) {
2426                         cvp->cookie_desired = ctd.tcpct_cookie_desired;
2427
2428                         if (ctd.tcpct_used > 0) {
2429                                 memcpy(cvp->s_data_payload, ctd.tcpct_value,
2430                                        ctd.tcpct_used);
2431                                 cvp->s_data_desired = ctd.tcpct_used;
2432                                 cvp->s_data_constant = 1; /* true */
2433                         } else {
2434                                 /* No constant payload data. */
2435                                 cvp->s_data_desired = ctd.tcpct_s_data_desired;
2436                                 cvp->s_data_constant = 0; /* false */
2437                         }
2438
2439                         tp->cookie_values = cvp;
2440                 }
2441                 release_sock(sk);
2442                 return err;
2443         }
2444         default:
2445                 /* fallthru */
2446                 break;
2447         }
2448
2449         if (optlen < sizeof(int))
2450                 return -EINVAL;
2451
2452         if (get_user(val, (int __user *)optval))
2453                 return -EFAULT;
2454
2455         lock_sock(sk);
2456
2457         switch (optname) {
2458         case TCP_MAXSEG:
2459                 /* Values greater than interface MTU won't take effect. However
2460                  * at the point when this call is done we typically don't yet
2461                  * know which interface is going to be used */
2462                 if (val < TCP_MIN_MSS || val > MAX_TCP_WINDOW) {
2463                         err = -EINVAL;
2464                         break;
2465                 }
2466                 tp->rx_opt.user_mss = val;
2467                 break;
2468
2469         case TCP_NODELAY:
2470                 if (val) {
2471                         /* TCP_NODELAY is weaker than TCP_CORK, so that
2472                          * this option on corked socket is remembered, but
2473                          * it is not activated until cork is cleared.
2474                          *
2475                          * However, when TCP_NODELAY is set we make
2476                          * an explicit push, which overrides even TCP_CORK
2477                          * for currently queued segments.
2478                          */
2479                         tp->nonagle |= TCP_NAGLE_OFF|TCP_NAGLE_PUSH;
2480                         tcp_push_pending_frames(sk);
2481                 } else {
2482                         tp->nonagle &= ~TCP_NAGLE_OFF;
2483                 }
2484                 break;
2485
2486         case TCP_THIN_LINEAR_TIMEOUTS:
2487                 if (val < 0 || val > 1)
2488                         err = -EINVAL;
2489                 else
2490                         tp->thin_lto = val;
2491                 break;
2492
2493         case TCP_THIN_DUPACK:
2494                 if (val < 0 || val > 1)
2495                         err = -EINVAL;
2496                 else
2497                         tp->thin_dupack = val;
2498                 break;
2499
2500         case TCP_REPAIR:
2501                 if (!tcp_can_repair_sock(sk))
2502                         err = -EPERM;
2503                 else if (val == 1) {
2504                         tp->repair = 1;
2505                         sk->sk_reuse = SK_FORCE_REUSE;
2506                         tp->repair_queue = TCP_NO_QUEUE;
2507                 } else if (val == 0) {
2508                         tp->repair = 0;
2509                         sk->sk_reuse = SK_NO_REUSE;
2510                         tcp_send_window_probe(sk);
2511                 } else
2512                         err = -EINVAL;
2513
2514                 break;
2515
2516         case TCP_REPAIR_QUEUE:
2517                 if (!tp->repair)
2518                         err = -EPERM;
2519                 else if (val < TCP_QUEUES_NR)
2520                         tp->repair_queue = val;
2521                 else
2522                         err = -EINVAL;
2523                 break;
2524
2525         case TCP_QUEUE_SEQ:
2526                 if (sk->sk_state != TCP_CLOSE)
2527                         err = -EPERM;
2528                 else if (tp->repair_queue == TCP_SEND_QUEUE)
2529                         tp->write_seq = val;
2530                 else if (tp->repair_queue == TCP_RECV_QUEUE)
2531                         tp->rcv_nxt = val;
2532                 else
2533                         err = -EINVAL;
2534                 break;
2535
2536         case TCP_REPAIR_OPTIONS:
2537                 if (!tp->repair)
2538                         err = -EINVAL;
2539                 else if (sk->sk_state == TCP_ESTABLISHED)
2540                         err = tcp_repair_options_est(tp,
2541                                         (struct tcp_repair_opt __user *)optval,
2542                                         optlen);
2543                 else
2544                         err = -EPERM;
2545                 break;
2546
2547         case TCP_CORK:
2548                 /* When set indicates to always queue non-full frames.
2549                  * Later the user clears this option and we transmit
2550                  * any pending partial frames in the queue.  This is
2551                  * meant to be used alongside sendfile() to get properly
2552                  * filled frames when the user (for example) must write
2553                  * out headers with a write() call first and then use
2554                  * sendfile to send out the data parts.
2555                  *
2556                  * TCP_CORK can be set together with TCP_NODELAY and it is
2557                  * stronger than TCP_NODELAY.
2558                  */
2559                 if (val) {
2560                         tp->nonagle |= TCP_NAGLE_CORK;
2561                 } else {
2562                         tp->nonagle &= ~TCP_NAGLE_CORK;
2563                         if (tp->nonagle&TCP_NAGLE_OFF)
2564                                 tp->nonagle |= TCP_NAGLE_PUSH;
2565                         tcp_push_pending_frames(sk);
2566                 }
2567                 break;
2568
2569         case TCP_KEEPIDLE:
2570                 if (val < 1 || val > MAX_TCP_KEEPIDLE)
2571                         err = -EINVAL;
2572                 else {
2573                         tp->keepalive_time = val * HZ;
2574                         if (sock_flag(sk, SOCK_KEEPOPEN) &&
2575                             !((1 << sk->sk_state) &
2576                               (TCPF_CLOSE | TCPF_LISTEN))) {
2577                                 u32 elapsed = keepalive_time_elapsed(tp);
2578                                 if (tp->keepalive_time > elapsed)
2579                                         elapsed = tp->keepalive_time - elapsed;
2580                                 else
2581                                         elapsed = 0;
2582                                 inet_csk_reset_keepalive_timer(sk, elapsed);
2583                         }
2584                 }
2585                 break;
2586         case TCP_KEEPINTVL:
2587                 if (val < 1 || val > MAX_TCP_KEEPINTVL)
2588                         err = -EINVAL;
2589                 else
2590                         tp->keepalive_intvl = val * HZ;
2591                 break;
2592         case TCP_KEEPCNT:
2593                 if (val < 1 || val > MAX_TCP_KEEPCNT)
2594                         err = -EINVAL;
2595                 else
2596                         tp->keepalive_probes = val;
2597                 break;
2598         case TCP_SYNCNT:
2599                 if (val < 1 || val > MAX_TCP_SYNCNT)
2600                         err = -EINVAL;
2601                 else
2602                         icsk->icsk_syn_retries = val;
2603                 break;
2604
2605         case TCP_LINGER2:
2606                 if (val < 0)
2607                         tp->linger2 = -1;
2608                 else if (val > sysctl_tcp_fin_timeout / HZ)
2609                         tp->linger2 = 0;
2610                 else
2611                         tp->linger2 = val * HZ;
2612                 break;
2613
2614         case TCP_DEFER_ACCEPT:
2615                 /* Translate value in seconds to number of retransmits */
2616                 icsk->icsk_accept_queue.rskq_defer_accept =
2617                         secs_to_retrans(val, TCP_TIMEOUT_INIT / HZ,
2618                                         TCP_RTO_MAX / HZ);
2619                 break;
2620
2621         case TCP_WINDOW_CLAMP:
2622                 if (!val) {
2623                         if (sk->sk_state != TCP_CLOSE) {
2624                                 err = -EINVAL;
2625                                 break;
2626                         }
2627                         tp->window_clamp = 0;
2628                 } else
2629                         tp->window_clamp = val < SOCK_MIN_RCVBUF / 2 ?
2630                                                 SOCK_MIN_RCVBUF / 2 : val;
2631                 break;
2632
2633         case TCP_QUICKACK:
2634                 if (!val) {
2635                         icsk->icsk_ack.pingpong = 1;
2636                 } else {
2637                         icsk->icsk_ack.pingpong = 0;
2638                         if ((1 << sk->sk_state) &
2639                             (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT) &&
2640                             inet_csk_ack_scheduled(sk)) {
2641                                 icsk->icsk_ack.pending |= ICSK_ACK_PUSHED;
2642                                 tcp_cleanup_rbuf(sk, 1);
2643                                 if (!(val & 1))
2644                                         icsk->icsk_ack.pingpong = 1;
2645                         }
2646                 }
2647                 break;
2648
2649 #ifdef CONFIG_TCP_MD5SIG
2650         case TCP_MD5SIG:
2651                 /* Read the IP->Key mappings from userspace */
2652                 err = tp->af_specific->md5_parse(sk, optval, optlen);
2653                 break;
2654 #endif
2655         case TCP_USER_TIMEOUT:
2656                 /* Cap the max timeout in ms TCP will retry/retrans
2657                  * before giving up and aborting (ETIMEDOUT) a connection.
2658                  */
2659                 icsk->icsk_user_timeout = msecs_to_jiffies(val);
2660                 break;
2661         default:
2662                 err = -ENOPROTOOPT;
2663                 break;
2664         }
2665
2666         release_sock(sk);
2667         return err;
2668 }
2669
2670 int tcp_setsockopt(struct sock *sk, int level, int optname, char __user *optval,
2671                    unsigned int optlen)
2672 {
2673         const struct inet_connection_sock *icsk = inet_csk(sk);
2674
2675         if (level != SOL_TCP)
2676                 return icsk->icsk_af_ops->setsockopt(sk, level, optname,
2677                                                      optval, optlen);
2678         return do_tcp_setsockopt(sk, level, optname, optval, optlen);
2679 }
2680 EXPORT_SYMBOL(tcp_setsockopt);
2681
2682 #ifdef CONFIG_COMPAT
2683 int compat_tcp_setsockopt(struct sock *sk, int level, int optname,
2684                           char __user *optval, unsigned int optlen)
2685 {
2686         if (level != SOL_TCP)
2687                 return inet_csk_compat_setsockopt(sk, level, optname,
2688                                                   optval, optlen);
2689         return do_tcp_setsockopt(sk, level, optname, optval, optlen);
2690 }
2691 EXPORT_SYMBOL(compat_tcp_setsockopt);
2692 #endif
2693
2694 /* Return information about state of tcp endpoint in API format. */
2695 void tcp_get_info(const struct sock *sk, struct tcp_info *info)
2696 {
2697         const struct tcp_sock *tp = tcp_sk(sk);
2698         const struct inet_connection_sock *icsk = inet_csk(sk);
2699         u32 now = tcp_time_stamp;
2700
2701         memset(info, 0, sizeof(*info));
2702
2703         info->tcpi_state = sk->sk_state;
2704         info->tcpi_ca_state = icsk->icsk_ca_state;
2705         info->tcpi_retransmits = icsk->icsk_retransmits;
2706         info->tcpi_probes = icsk->icsk_probes_out;
2707         info->tcpi_backoff = icsk->icsk_backoff;
2708
2709         if (tp->rx_opt.tstamp_ok)
2710                 info->tcpi_options |= TCPI_OPT_TIMESTAMPS;
2711         if (tcp_is_sack(tp))
2712                 info->tcpi_options |= TCPI_OPT_SACK;
2713         if (tp->rx_opt.wscale_ok) {
2714                 info->tcpi_options |= TCPI_OPT_WSCALE;
2715                 info->tcpi_snd_wscale = tp->rx_opt.snd_wscale;
2716                 info->tcpi_rcv_wscale = tp->rx_opt.rcv_wscale;
2717         }
2718
2719         if (tp->ecn_flags & TCP_ECN_OK)
2720                 info->tcpi_options |= TCPI_OPT_ECN;
2721         if (tp->ecn_flags & TCP_ECN_SEEN)
2722                 info->tcpi_options |= TCPI_OPT_ECN_SEEN;
2723
2724         info->tcpi_rto = jiffies_to_usecs(icsk->icsk_rto);
2725         info->tcpi_ato = jiffies_to_usecs(icsk->icsk_ack.ato);
2726         info->tcpi_snd_mss = tp->mss_cache;
2727         info->tcpi_rcv_mss = icsk->icsk_ack.rcv_mss;
2728
2729         if (sk->sk_state == TCP_LISTEN) {
2730                 info->tcpi_unacked = sk->sk_ack_backlog;
2731                 info->tcpi_sacked = sk->sk_max_ack_backlog;
2732         } else {
2733                 info->tcpi_unacked = tp->packets_out;
2734                 info->tcpi_sacked = tp->sacked_out;
2735         }
2736         info->tcpi_lost = tp->lost_out;
2737         info->tcpi_retrans = tp->retrans_out;
2738         info->tcpi_fackets = tp->fackets_out;
2739
2740         info->tcpi_last_data_sent = jiffies_to_msecs(now - tp->lsndtime);
2741         info->tcpi_last_data_recv = jiffies_to_msecs(now - icsk->icsk_ack.lrcvtime);
2742         info->tcpi_last_ack_recv = jiffies_to_msecs(now - tp->rcv_tstamp);
2743
2744         info->tcpi_pmtu = icsk->icsk_pmtu_cookie;
2745         info->tcpi_rcv_ssthresh = tp->rcv_ssthresh;
2746         info->tcpi_rtt = jiffies_to_usecs(tp->srtt)>>3;
2747         info->tcpi_rttvar = jiffies_to_usecs(tp->mdev)>>2;
2748         info->tcpi_snd_ssthresh = tp->snd_ssthresh;
2749         info->tcpi_snd_cwnd = tp->snd_cwnd;
2750         info->tcpi_advmss = tp->advmss;
2751         info->tcpi_reordering = tp->reordering;
2752
2753         info->tcpi_rcv_rtt = jiffies_to_usecs(tp->rcv_rtt_est.rtt)>>3;
2754         info->tcpi_rcv_space = tp->rcvq_space.space;
2755
2756         info->tcpi_total_retrans = tp->total_retrans;
2757 }
2758 EXPORT_SYMBOL_GPL(tcp_get_info);
2759
2760 static int do_tcp_getsockopt(struct sock *sk, int level,
2761                 int optname, char __user *optval, int __user *optlen)
2762 {
2763         struct inet_connection_sock *icsk = inet_csk(sk);
2764         struct tcp_sock *tp = tcp_sk(sk);
2765         int val, len;
2766
2767         if (get_user(len, optlen))
2768                 return -EFAULT;
2769
2770         len = min_t(unsigned int, len, sizeof(int));
2771
2772         if (len < 0)
2773                 return -EINVAL;
2774
2775         switch (optname) {
2776         case TCP_MAXSEG:
2777                 val = tp->mss_cache;
2778                 if (!val && ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN)))
2779                         val = tp->rx_opt.user_mss;
2780                 if (tp->repair)
2781                         val = tp->rx_opt.mss_clamp;
2782                 break;
2783         case TCP_NODELAY:
2784                 val = !!(tp->nonagle&TCP_NAGLE_OFF);
2785                 break;
2786         case TCP_CORK:
2787                 val = !!(tp->nonagle&TCP_NAGLE_CORK);
2788                 break;
2789         case TCP_KEEPIDLE:
2790                 val = keepalive_time_when(tp) / HZ;
2791                 break;
2792         case TCP_KEEPINTVL:
2793                 val = keepalive_intvl_when(tp) / HZ;
2794                 break;
2795         case TCP_KEEPCNT:
2796                 val = keepalive_probes(tp);
2797                 break;
2798         case TCP_SYNCNT:
2799                 val = icsk->icsk_syn_retries ? : sysctl_tcp_syn_retries;
2800                 break;
2801         case TCP_LINGER2:
2802                 val = tp->linger2;
2803                 if (val >= 0)
2804                         val = (val ? : sysctl_tcp_fin_timeout) / HZ;
2805                 break;
2806         case TCP_DEFER_ACCEPT:
2807                 val = retrans_to_secs(icsk->icsk_accept_queue.rskq_defer_accept,
2808                                       TCP_TIMEOUT_INIT / HZ, TCP_RTO_MAX / HZ);
2809                 break;
2810         case TCP_WINDOW_CLAMP:
2811                 val = tp->window_clamp;
2812                 break;
2813         case TCP_INFO: {
2814                 struct tcp_info info;
2815
2816                 if (get_user(len, optlen))
2817                         return -EFAULT;
2818
2819                 tcp_get_info(sk, &info);
2820
2821                 len = min_t(unsigned int, len, sizeof(info));
2822                 if (put_user(len, optlen))
2823                         return -EFAULT;
2824                 if (copy_to_user(optval, &info, len))
2825                         return -EFAULT;
2826                 return 0;
2827         }
2828         case TCP_QUICKACK:
2829                 val = !icsk->icsk_ack.pingpong;
2830                 break;
2831
2832         case TCP_CONGESTION:
2833                 if (get_user(len, optlen))
2834                         return -EFAULT;
2835                 len = min_t(unsigned int, len, TCP_CA_NAME_MAX);
2836                 if (put_user(len, optlen))
2837                         return -EFAULT;
2838                 if (copy_to_user(optval, icsk->icsk_ca_ops->name, len))
2839                         return -EFAULT;
2840                 return 0;
2841
2842         case TCP_COOKIE_TRANSACTIONS: {
2843                 struct tcp_cookie_transactions ctd;
2844                 struct tcp_cookie_values *cvp = tp->cookie_values;
2845
2846                 if (get_user(len, optlen))
2847                         return -EFAULT;
2848                 if (len < sizeof(ctd))
2849                         return -EINVAL;
2850
2851                 memset(&ctd, 0, sizeof(ctd));
2852                 ctd.tcpct_flags = (tp->rx_opt.cookie_in_always ?
2853                                    TCP_COOKIE_IN_ALWAYS : 0)
2854                                 | (tp->rx_opt.cookie_out_never ?
2855                                    TCP_COOKIE_OUT_NEVER : 0);
2856
2857                 if (cvp != NULL) {
2858                         ctd.tcpct_flags |= (cvp->s_data_in ?
2859                                             TCP_S_DATA_IN : 0)
2860                                          | (cvp->s_data_out ?
2861                                             TCP_S_DATA_OUT : 0);
2862
2863                         ctd.tcpct_cookie_desired = cvp->cookie_desired;
2864                         ctd.tcpct_s_data_desired = cvp->s_data_desired;
2865
2866                         memcpy(&ctd.tcpct_value[0], &cvp->cookie_pair[0],
2867                                cvp->cookie_pair_size);
2868                         ctd.tcpct_used = cvp->cookie_pair_size;
2869                 }
2870
2871                 if (put_user(sizeof(ctd), optlen))
2872                         return -EFAULT;
2873                 if (copy_to_user(optval, &ctd, sizeof(ctd)))
2874                         return -EFAULT;
2875                 return 0;
2876         }
2877         case TCP_THIN_LINEAR_TIMEOUTS:
2878                 val = tp->thin_lto;
2879                 break;
2880         case TCP_THIN_DUPACK:
2881                 val = tp->thin_dupack;
2882                 break;
2883
2884         case TCP_REPAIR:
2885                 val = tp->repair;
2886                 break;
2887
2888         case TCP_REPAIR_QUEUE:
2889                 if (tp->repair)
2890                         val = tp->repair_queue;
2891                 else
2892                         return -EINVAL;
2893                 break;
2894
2895         case TCP_QUEUE_SEQ:
2896                 if (tp->repair_queue == TCP_SEND_QUEUE)
2897                         val = tp->write_seq;
2898                 else if (tp->repair_queue == TCP_RECV_QUEUE)
2899                         val = tp->rcv_nxt;
2900                 else
2901                         return -EINVAL;
2902                 break;
2903
2904         case TCP_USER_TIMEOUT:
2905                 val = jiffies_to_msecs(icsk->icsk_user_timeout);
2906                 break;
2907         default:
2908                 return -ENOPROTOOPT;
2909         }
2910
2911         if (put_user(len, optlen))
2912                 return -EFAULT;
2913         if (copy_to_user(optval, &val, len))
2914                 return -EFAULT;
2915         return 0;
2916 }
2917
2918 int tcp_getsockopt(struct sock *sk, int level, int optname, char __user *optval,
2919                    int __user *optlen)
2920 {
2921         struct inet_connection_sock *icsk = inet_csk(sk);
2922
2923         if (level != SOL_TCP)
2924                 return icsk->icsk_af_ops->getsockopt(sk, level, optname,
2925                                                      optval, optlen);
2926         return do_tcp_getsockopt(sk, level, optname, optval, optlen);
2927 }
2928 EXPORT_SYMBOL(tcp_getsockopt);
2929
2930 #ifdef CONFIG_COMPAT
2931 int compat_tcp_getsockopt(struct sock *sk, int level, int optname,
2932                           char __user *optval, int __user *optlen)
2933 {
2934         if (level != SOL_TCP)
2935                 return inet_csk_compat_getsockopt(sk, level, optname,
2936                                                   optval, optlen);
2937         return do_tcp_getsockopt(sk, level, optname, optval, optlen);
2938 }
2939 EXPORT_SYMBOL(compat_tcp_getsockopt);
2940 #endif
2941
2942 struct sk_buff *tcp_tso_segment(struct sk_buff *skb,
2943         netdev_features_t features)
2944 {
2945         struct sk_buff *segs = ERR_PTR(-EINVAL);
2946         struct tcphdr *th;
2947         unsigned int thlen;
2948         unsigned int seq;
2949         __be32 delta;
2950         unsigned int oldlen;
2951         unsigned int mss;
2952
2953         if (!pskb_may_pull(skb, sizeof(*th)))
2954                 goto out;
2955
2956         th = tcp_hdr(skb);
2957         thlen = th->doff * 4;
2958         if (thlen < sizeof(*th))
2959                 goto out;
2960
2961         if (!pskb_may_pull(skb, thlen))
2962                 goto out;
2963
2964         oldlen = (u16)~skb->len;
2965         __skb_pull(skb, thlen);
2966
2967         mss = skb_shinfo(skb)->gso_size;
2968         if (unlikely(skb->len <= mss))
2969                 goto out;
2970
2971         if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) {
2972                 /* Packet is from an untrusted source, reset gso_segs. */
2973                 int type = skb_shinfo(skb)->gso_type;
2974
2975                 if (unlikely(type &
2976                              ~(SKB_GSO_TCPV4 |
2977                                SKB_GSO_DODGY |
2978                                SKB_GSO_TCP_ECN |
2979                                SKB_GSO_TCPV6 |
2980                                0) ||
2981                              !(type & (SKB_GSO_TCPV4 | SKB_GSO_TCPV6))))
2982                         goto out;
2983
2984                 skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss);
2985
2986                 segs = NULL;
2987                 goto out;
2988         }
2989
2990         segs = skb_segment(skb, features);
2991         if (IS_ERR(segs))
2992                 goto out;
2993
2994         delta = htonl(oldlen + (thlen + mss));
2995
2996         skb = segs;
2997         th = tcp_hdr(skb);
2998         seq = ntohl(th->seq);
2999
3000         do {
3001                 th->fin = th->psh = 0;
3002
3003                 th->check = ~csum_fold((__force __wsum)((__force u32)th->check +
3004                                        (__force u32)delta));
3005                 if (skb->ip_summed != CHECKSUM_PARTIAL)
3006                         th->check =
3007                              csum_fold(csum_partial(skb_transport_header(skb),
3008                                                     thlen, skb->csum));
3009
3010                 seq += mss;
3011                 skb = skb->next;
3012                 th = tcp_hdr(skb);
3013
3014                 th->seq = htonl(seq);
3015                 th->cwr = 0;
3016         } while (skb->next);
3017
3018         delta = htonl(oldlen + (skb->tail - skb->transport_header) +
3019                       skb->data_len);
3020         th->check = ~csum_fold((__force __wsum)((__force u32)th->check +
3021                                 (__force u32)delta));
3022         if (skb->ip_summed != CHECKSUM_PARTIAL)
3023                 th->check = csum_fold(csum_partial(skb_transport_header(skb),
3024                                                    thlen, skb->csum));
3025
3026 out:
3027         return segs;
3028 }
3029 EXPORT_SYMBOL(tcp_tso_segment);
3030
3031 struct sk_buff **tcp_gro_receive(struct sk_buff **head, struct sk_buff *skb)
3032 {
3033         struct sk_buff **pp = NULL;
3034         struct sk_buff *p;
3035         struct tcphdr *th;
3036         struct tcphdr *th2;
3037         unsigned int len;
3038         unsigned int thlen;
3039         __be32 flags;
3040         unsigned int mss = 1;
3041         unsigned int hlen;
3042         unsigned int off;
3043         int flush = 1;
3044         int i;
3045
3046         off = skb_gro_offset(skb);
3047         hlen = off + sizeof(*th);
3048         th = skb_gro_header_fast(skb, off);
3049         if (skb_gro_header_hard(skb, hlen)) {
3050                 th = skb_gro_header_slow(skb, hlen, off);
3051                 if (unlikely(!th))
3052                         goto out;
3053         }
3054
3055         thlen = th->doff * 4;
3056         if (thlen < sizeof(*th))
3057                 goto out;
3058
3059         hlen = off + thlen;
3060         if (skb_gro_header_hard(skb, hlen)) {
3061                 th = skb_gro_header_slow(skb, hlen, off);
3062                 if (unlikely(!th))
3063                         goto out;
3064         }
3065
3066         skb_gro_pull(skb, thlen);
3067
3068         len = skb_gro_len(skb);
3069         flags = tcp_flag_word(th);
3070
3071         for (; (p = *head); head = &p->next) {
3072                 if (!NAPI_GRO_CB(p)->same_flow)
3073                         continue;
3074
3075                 th2 = tcp_hdr(p);
3076
3077                 if (*(u32 *)&th->source ^ *(u32 *)&th2->source) {
3078                         NAPI_GRO_CB(p)->same_flow = 0;
3079                         continue;
3080                 }
3081
3082                 goto found;
3083         }
3084
3085         goto out_check_final;
3086
3087 found:
3088         flush = NAPI_GRO_CB(p)->flush;
3089         flush |= (__force int)(flags & TCP_FLAG_CWR);
3090         flush |= (__force int)((flags ^ tcp_flag_word(th2)) &
3091                   ~(TCP_FLAG_CWR | TCP_FLAG_FIN | TCP_FLAG_PSH));
3092         flush |= (__force int)(th->ack_seq ^ th2->ack_seq);
3093         for (i = sizeof(*th); i < thlen; i += 4)
3094                 flush |= *(u32 *)((u8 *)th + i) ^
3095                          *(u32 *)((u8 *)th2 + i);
3096
3097         mss = skb_shinfo(p)->gso_size;
3098
3099         flush |= (len - 1) >= mss;
3100         flush |= (ntohl(th2->seq) + skb_gro_len(p)) ^ ntohl(th->seq);
3101
3102         if (flush || skb_gro_receive(head, skb)) {
3103                 mss = 1;
3104                 goto out_check_final;
3105         }
3106
3107         p = *head;
3108         th2 = tcp_hdr(p);
3109         tcp_flag_word(th2) |= flags & (TCP_FLAG_FIN | TCP_FLAG_PSH);
3110
3111 out_check_final:
3112         flush = len < mss;
3113         flush |= (__force int)(flags & (TCP_FLAG_URG | TCP_FLAG_PSH |
3114                                         TCP_FLAG_RST | TCP_FLAG_SYN |
3115                                         TCP_FLAG_FIN));
3116
3117         if (p && (!NAPI_GRO_CB(skb)->same_flow || flush))
3118                 pp = head;
3119
3120 out:
3121         NAPI_GRO_CB(skb)->flush |= flush;
3122
3123         return pp;
3124 }
3125 EXPORT_SYMBOL(tcp_gro_receive);
3126
3127 int tcp_gro_complete(struct sk_buff *skb)
3128 {
3129         struct tcphdr *th = tcp_hdr(skb);
3130
3131         skb->csum_start = skb_transport_header(skb) - skb->head;
3132         skb->csum_offset = offsetof(struct tcphdr, check);
3133         skb->ip_summed = CHECKSUM_PARTIAL;
3134
3135         skb_shinfo(skb)->gso_segs = NAPI_GRO_CB(skb)->count;
3136
3137         if (th->cwr)
3138                 skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
3139
3140         return 0;
3141 }
3142 EXPORT_SYMBOL(tcp_gro_complete);
3143
3144 #ifdef CONFIG_TCP_MD5SIG
3145 static unsigned long tcp_md5sig_users;
3146 static struct tcp_md5sig_pool __percpu *tcp_md5sig_pool;
3147 static DEFINE_SPINLOCK(tcp_md5sig_pool_lock);
3148
3149 static void __tcp_free_md5sig_pool(struct tcp_md5sig_pool __percpu *pool)
3150 {
3151         int cpu;
3152
3153         for_each_possible_cpu(cpu) {
3154                 struct tcp_md5sig_pool *p = per_cpu_ptr(pool, cpu);
3155
3156                 if (p->md5_desc.tfm)
3157                         crypto_free_hash(p->md5_desc.tfm);
3158         }
3159         free_percpu(pool);
3160 }
3161
3162 void tcp_free_md5sig_pool(void)
3163 {
3164         struct tcp_md5sig_pool __percpu *pool = NULL;
3165
3166         spin_lock_bh(&tcp_md5sig_pool_lock);
3167         if (--tcp_md5sig_users == 0) {
3168                 pool = tcp_md5sig_pool;
3169                 tcp_md5sig_pool = NULL;
3170         }
3171         spin_unlock_bh(&tcp_md5sig_pool_lock);
3172         if (pool)
3173                 __tcp_free_md5sig_pool(pool);
3174 }
3175 EXPORT_SYMBOL(tcp_free_md5sig_pool);
3176
3177 static struct tcp_md5sig_pool __percpu *
3178 __tcp_alloc_md5sig_pool(struct sock *sk)
3179 {
3180         int cpu;
3181         struct tcp_md5sig_pool __percpu *pool;
3182
3183         pool = alloc_percpu(struct tcp_md5sig_pool);
3184         if (!pool)
3185                 return NULL;
3186
3187         for_each_possible_cpu(cpu) {
3188                 struct crypto_hash *hash;
3189
3190                 hash = crypto_alloc_hash("md5", 0, CRYPTO_ALG_ASYNC);
3191                 if (!hash || IS_ERR(hash))
3192                         goto out_free;
3193
3194                 per_cpu_ptr(pool, cpu)->md5_desc.tfm = hash;
3195         }
3196         return pool;
3197 out_free:
3198         __tcp_free_md5sig_pool(pool);
3199         return NULL;
3200 }
3201
3202 struct tcp_md5sig_pool __percpu *tcp_alloc_md5sig_pool(struct sock *sk)
3203 {
3204         struct tcp_md5sig_pool __percpu *pool;
3205         int alloc = 0;
3206
3207 retry:
3208         spin_lock_bh(&tcp_md5sig_pool_lock);
3209         pool = tcp_md5sig_pool;
3210         if (tcp_md5sig_users++ == 0) {
3211                 alloc = 1;
3212                 spin_unlock_bh(&tcp_md5sig_pool_lock);
3213         } else if (!pool) {
3214                 tcp_md5sig_users--;
3215                 spin_unlock_bh(&tcp_md5sig_pool_lock);
3216                 cpu_relax();
3217                 goto retry;
3218         } else
3219                 spin_unlock_bh(&tcp_md5sig_pool_lock);
3220
3221         if (alloc) {
3222                 /* we cannot hold spinlock here because this may sleep. */
3223                 struct tcp_md5sig_pool __percpu *p;
3224
3225                 p = __tcp_alloc_md5sig_pool(sk);
3226                 spin_lock_bh(&tcp_md5sig_pool_lock);
3227                 if (!p) {
3228                         tcp_md5sig_users--;
3229                         spin_unlock_bh(&tcp_md5sig_pool_lock);
3230                         return NULL;
3231                 }
3232                 pool = tcp_md5sig_pool;
3233                 if (pool) {
3234                         /* oops, it has already been assigned. */
3235                         spin_unlock_bh(&tcp_md5sig_pool_lock);
3236                         __tcp_free_md5sig_pool(p);
3237                 } else {
3238                         tcp_md5sig_pool = pool = p;
3239                         spin_unlock_bh(&tcp_md5sig_pool_lock);
3240                 }
3241         }
3242         return pool;
3243 }
3244 EXPORT_SYMBOL(tcp_alloc_md5sig_pool);
3245
3246
3247 /**
3248  *      tcp_get_md5sig_pool - get md5sig_pool for this user
3249  *
3250  *      We use percpu structure, so if we succeed, we exit with preemption
3251  *      and BH disabled, to make sure another thread or softirq handling
3252  *      wont try to get same context.
3253  */
3254 struct tcp_md5sig_pool *tcp_get_md5sig_pool(void)
3255 {
3256         struct tcp_md5sig_pool __percpu *p;
3257
3258         local_bh_disable();
3259
3260         spin_lock(&tcp_md5sig_pool_lock);
3261         p = tcp_md5sig_pool;
3262         if (p)
3263                 tcp_md5sig_users++;
3264         spin_unlock(&tcp_md5sig_pool_lock);
3265
3266         if (p)
3267                 return this_cpu_ptr(p);
3268
3269         local_bh_enable();
3270         return NULL;
3271 }
3272 EXPORT_SYMBOL(tcp_get_md5sig_pool);
3273
3274 void tcp_put_md5sig_pool(void)
3275 {
3276         local_bh_enable();
3277         tcp_free_md5sig_pool();
3278 }
3279 EXPORT_SYMBOL(tcp_put_md5sig_pool);
3280
3281 int tcp_md5_hash_header(struct tcp_md5sig_pool *hp,
3282                         const struct tcphdr *th)
3283 {
3284         struct scatterlist sg;
3285         struct tcphdr hdr;
3286         int err;
3287
3288         /* We are not allowed to change tcphdr, make a local copy */
3289         memcpy(&hdr, th, sizeof(hdr));
3290         hdr.check = 0;
3291
3292         /* options aren't included in the hash */
3293         sg_init_one(&sg, &hdr, sizeof(hdr));
3294         err = crypto_hash_update(&hp->md5_desc, &sg, sizeof(hdr));
3295         return err;
3296 }
3297 EXPORT_SYMBOL(tcp_md5_hash_header);
3298
3299 int tcp_md5_hash_skb_data(struct tcp_md5sig_pool *hp,
3300                           const struct sk_buff *skb, unsigned int header_len)
3301 {
3302         struct scatterlist sg;
3303         const struct tcphdr *tp = tcp_hdr(skb);
3304         struct hash_desc *desc = &hp->md5_desc;
3305         unsigned int i;
3306         const unsigned int head_data_len = skb_headlen(skb) > header_len ?
3307                                            skb_headlen(skb) - header_len : 0;
3308         const struct skb_shared_info *shi = skb_shinfo(skb);
3309         struct sk_buff *frag_iter;
3310
3311         sg_init_table(&sg, 1);
3312
3313         sg_set_buf(&sg, ((u8 *) tp) + header_len, head_data_len);
3314         if (crypto_hash_update(desc, &sg, head_data_len))
3315                 return 1;
3316
3317         for (i = 0; i < shi->nr_frags; ++i) {
3318                 const struct skb_frag_struct *f = &shi->frags[i];
3319                 struct page *page = skb_frag_page(f);
3320                 sg_set_page(&sg, page, skb_frag_size(f), f->page_offset);
3321                 if (crypto_hash_update(desc, &sg, skb_frag_size(f)))
3322                         return 1;
3323         }
3324
3325         skb_walk_frags(skb, frag_iter)
3326                 if (tcp_md5_hash_skb_data(hp, frag_iter, 0))
3327                         return 1;
3328
3329         return 0;
3330 }
3331 EXPORT_SYMBOL(tcp_md5_hash_skb_data);
3332
3333 int tcp_md5_hash_key(struct tcp_md5sig_pool *hp, const struct tcp_md5sig_key *key)
3334 {
3335         struct scatterlist sg;
3336
3337         sg_init_one(&sg, key->key, key->keylen);
3338         return crypto_hash_update(&hp->md5_desc, &sg, key->keylen);
3339 }
3340 EXPORT_SYMBOL(tcp_md5_hash_key);
3341
3342 #endif
3343
3344 /**
3345  * Each Responder maintains up to two secret values concurrently for
3346  * efficient secret rollover.  Each secret value has 4 states:
3347  *
3348  * Generating.  (tcp_secret_generating != tcp_secret_primary)
3349  *    Generates new Responder-Cookies, but not yet used for primary
3350  *    verification.  This is a short-term state, typically lasting only
3351  *    one round trip time (RTT).
3352  *
3353  * Primary.  (tcp_secret_generating == tcp_secret_primary)
3354  *    Used both for generation and primary verification.
3355  *
3356  * Retiring.  (tcp_secret_retiring != tcp_secret_secondary)
3357  *    Used for verification, until the first failure that can be
3358  *    verified by the newer Generating secret.  At that time, this
3359  *    cookie's state is changed to Secondary, and the Generating
3360  *    cookie's state is changed to Primary.  This is a short-term state,
3361  *    typically lasting only one round trip time (RTT).
3362  *
3363  * Secondary.  (tcp_secret_retiring == tcp_secret_secondary)
3364  *    Used for secondary verification, after primary verification
3365  *    failures.  This state lasts no more than twice the Maximum Segment
3366  *    Lifetime (2MSL).  Then, the secret is discarded.
3367  */
3368 struct tcp_cookie_secret {
3369         /* The secret is divided into two parts.  The digest part is the
3370          * equivalent of previously hashing a secret and saving the state,
3371          * and serves as an initialization vector (IV).  The message part
3372          * serves as the trailing secret.
3373          */
3374         u32                             secrets[COOKIE_WORKSPACE_WORDS];
3375         unsigned long                   expires;
3376 };
3377
3378 #define TCP_SECRET_1MSL (HZ * TCP_PAWS_MSL)
3379 #define TCP_SECRET_2MSL (HZ * TCP_PAWS_MSL * 2)
3380 #define TCP_SECRET_LIFE (HZ * 600)
3381
3382 static struct tcp_cookie_secret tcp_secret_one;
3383 static struct tcp_cookie_secret tcp_secret_two;
3384
3385 /* Essentially a circular list, without dynamic allocation. */
3386 static struct tcp_cookie_secret *tcp_secret_generating;
3387 static struct tcp_cookie_secret *tcp_secret_primary;
3388 static struct tcp_cookie_secret *tcp_secret_retiring;
3389 static struct tcp_cookie_secret *tcp_secret_secondary;
3390
3391 static DEFINE_SPINLOCK(tcp_secret_locker);
3392
3393 /* Select a pseudo-random word in the cookie workspace.
3394  */
3395 static inline u32 tcp_cookie_work(const u32 *ws, const int n)
3396 {
3397         return ws[COOKIE_DIGEST_WORDS + ((COOKIE_MESSAGE_WORDS-1) & ws[n])];
3398 }
3399
3400 /* Fill bakery[COOKIE_WORKSPACE_WORDS] with generator, updating as needed.
3401  * Called in softirq context.
3402  * Returns: 0 for success.
3403  */
3404 int tcp_cookie_generator(u32 *bakery)
3405 {
3406         unsigned long jiffy = jiffies;
3407
3408         if (unlikely(time_after_eq(jiffy, tcp_secret_generating->expires))) {
3409                 spin_lock_bh(&tcp_secret_locker);
3410                 if (!time_after_eq(jiffy, tcp_secret_generating->expires)) {
3411                         /* refreshed by another */
3412                         memcpy(bakery,
3413                                &tcp_secret_generating->secrets[0],
3414                                COOKIE_WORKSPACE_WORDS);
3415                 } else {
3416                         /* still needs refreshing */
3417                         get_random_bytes(bakery, COOKIE_WORKSPACE_WORDS);
3418
3419                         /* The first time, paranoia assumes that the
3420                          * randomization function isn't as strong.  But,
3421                          * this secret initialization is delayed until
3422                          * the last possible moment (packet arrival).
3423                          * Although that time is observable, it is
3424                          * unpredictably variable.  Mash in the most
3425                          * volatile clock bits available, and expire the
3426                          * secret extra quickly.
3427                          */
3428                         if (unlikely(tcp_secret_primary->expires ==
3429                                      tcp_secret_secondary->expires)) {
3430                                 struct timespec tv;
3431
3432                                 getnstimeofday(&tv);
3433                                 bakery[COOKIE_DIGEST_WORDS+0] ^=
3434                                         (u32)tv.tv_nsec;
3435
3436                                 tcp_secret_secondary->expires = jiffy
3437                                         + TCP_SECRET_1MSL
3438                                         + (0x0f & tcp_cookie_work(bakery, 0));
3439                         } else {
3440                                 tcp_secret_secondary->expires = jiffy
3441                                         + TCP_SECRET_LIFE
3442                                         + (0xff & tcp_cookie_work(bakery, 1));
3443                                 tcp_secret_primary->expires = jiffy
3444                                         + TCP_SECRET_2MSL
3445                                         + (0x1f & tcp_cookie_work(bakery, 2));
3446                         }
3447                         memcpy(&tcp_secret_secondary->secrets[0],
3448                                bakery, COOKIE_WORKSPACE_WORDS);
3449
3450                         rcu_assign_pointer(tcp_secret_generating,
3451                                            tcp_secret_secondary);
3452                         rcu_assign_pointer(tcp_secret_retiring,
3453                                            tcp_secret_primary);
3454                         /*
3455                          * Neither call_rcu() nor synchronize_rcu() needed.
3456                          * Retiring data is not freed.  It is replaced after
3457                          * further (locked) pointer updates, and a quiet time
3458                          * (minimum 1MSL, maximum LIFE - 2MSL).
3459                          */
3460                 }
3461                 spin_unlock_bh(&tcp_secret_locker);
3462         } else {
3463                 rcu_read_lock_bh();
3464                 memcpy(bakery,
3465                        &rcu_dereference(tcp_secret_generating)->secrets[0],
3466                        COOKIE_WORKSPACE_WORDS);
3467                 rcu_read_unlock_bh();
3468         }
3469         return 0;
3470 }
3471 EXPORT_SYMBOL(tcp_cookie_generator);
3472
3473 void tcp_done(struct sock *sk)
3474 {
3475         if (sk->sk_state == TCP_SYN_SENT || sk->sk_state == TCP_SYN_RECV)
3476                 TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_ATTEMPTFAILS);
3477
3478         tcp_set_state(sk, TCP_CLOSE);
3479         tcp_clear_xmit_timers(sk);
3480
3481         sk->sk_shutdown = SHUTDOWN_MASK;
3482
3483         if (!sock_flag(sk, SOCK_DEAD))
3484                 sk->sk_state_change(sk);
3485         else
3486                 inet_csk_destroy_sock(sk);
3487 }
3488 EXPORT_SYMBOL_GPL(tcp_done);
3489
3490 extern struct tcp_congestion_ops tcp_reno;
3491
3492 static __initdata unsigned long thash_entries;
3493 static int __init set_thash_entries(char *str)
3494 {
3495         if (!str)
3496                 return 0;
3497         thash_entries = simple_strtoul(str, &str, 0);
3498         return 1;
3499 }
3500 __setup("thash_entries=", set_thash_entries);
3501
3502 void tcp_init_mem(struct net *net)
3503 {
3504         unsigned long limit = nr_free_buffer_pages() / 8;
3505         limit = max(limit, 128UL);
3506         net->ipv4.sysctl_tcp_mem[0] = limit / 4 * 3;
3507         net->ipv4.sysctl_tcp_mem[1] = limit;
3508         net->ipv4.sysctl_tcp_mem[2] = net->ipv4.sysctl_tcp_mem[0] * 2;
3509 }
3510
3511 void __init tcp_init(void)
3512 {
3513         struct sk_buff *skb = NULL;
3514         unsigned long limit;
3515         int max_share, cnt;
3516         unsigned int i;
3517         unsigned long jiffy = jiffies;
3518
3519         BUILD_BUG_ON(sizeof(struct tcp_skb_cb) > sizeof(skb->cb));
3520
3521         percpu_counter_init(&tcp_sockets_allocated, 0);
3522         percpu_counter_init(&tcp_orphan_count, 0);
3523         tcp_hashinfo.bind_bucket_cachep =
3524                 kmem_cache_create("tcp_bind_bucket",
3525                                   sizeof(struct inet_bind_bucket), 0,
3526                                   SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
3527
3528         /* Size and allocate the main established and bind bucket
3529          * hash tables.
3530          *
3531          * The methodology is similar to that of the buffer cache.
3532          */
3533         tcp_hashinfo.ehash =
3534                 alloc_large_system_hash("TCP established",
3535                                         sizeof(struct inet_ehash_bucket),
3536                                         thash_entries,
3537                                         (totalram_pages >= 128 * 1024) ?
3538                                         13 : 15,
3539                                         0,
3540                                         NULL,
3541                                         &tcp_hashinfo.ehash_mask,
3542                                         thash_entries ? 0 : 512 * 1024);
3543         for (i = 0; i <= tcp_hashinfo.ehash_mask; i++) {
3544                 INIT_HLIST_NULLS_HEAD(&tcp_hashinfo.ehash[i].chain, i);
3545                 INIT_HLIST_NULLS_HEAD(&tcp_hashinfo.ehash[i].twchain, i);
3546         }
3547         if (inet_ehash_locks_alloc(&tcp_hashinfo))
3548                 panic("TCP: failed to alloc ehash_locks");
3549         tcp_hashinfo.bhash =
3550                 alloc_large_system_hash("TCP bind",
3551                                         sizeof(struct inet_bind_hashbucket),
3552                                         tcp_hashinfo.ehash_mask + 1,
3553                                         (totalram_pages >= 128 * 1024) ?
3554                                         13 : 15,
3555                                         0,
3556                                         &tcp_hashinfo.bhash_size,
3557                                         NULL,
3558                                         64 * 1024);
3559         tcp_hashinfo.bhash_size = 1U << tcp_hashinfo.bhash_size;
3560         for (i = 0; i < tcp_hashinfo.bhash_size; i++) {
3561                 spin_lock_init(&tcp_hashinfo.bhash[i].lock);
3562                 INIT_HLIST_HEAD(&tcp_hashinfo.bhash[i].chain);
3563         }
3564
3565
3566         cnt = tcp_hashinfo.ehash_mask + 1;
3567
3568         tcp_death_row.sysctl_max_tw_buckets = cnt / 2;
3569         sysctl_tcp_max_orphans = cnt / 2;
3570         sysctl_max_syn_backlog = max(128, cnt / 256);
3571
3572         tcp_init_mem(&init_net);
3573         /* Set per-socket limits to no more than 1/128 the pressure threshold */
3574         limit = nr_free_buffer_pages() << (PAGE_SHIFT - 7);
3575         max_share = min(4UL*1024*1024, limit);
3576
3577         sysctl_tcp_wmem[0] = SK_MEM_QUANTUM;
3578         sysctl_tcp_wmem[1] = 16*1024;
3579         sysctl_tcp_wmem[2] = max(64*1024, max_share);
3580
3581         sysctl_tcp_rmem[0] = SK_MEM_QUANTUM;
3582         sysctl_tcp_rmem[1] = 87380;
3583         sysctl_tcp_rmem[2] = max(87380, max_share);
3584
3585         pr_info("Hash tables configured (established %u bind %u)\n",
3586                 tcp_hashinfo.ehash_mask + 1, tcp_hashinfo.bhash_size);
3587
3588         tcp_register_congestion_control(&tcp_reno);
3589
3590         memset(&tcp_secret_one.secrets[0], 0, sizeof(tcp_secret_one.secrets));
3591         memset(&tcp_secret_two.secrets[0], 0, sizeof(tcp_secret_two.secrets));
3592         tcp_secret_one.expires = jiffy; /* past due */
3593         tcp_secret_two.expires = jiffy; /* past due */
3594         tcp_secret_generating = &tcp_secret_one;
3595         tcp_secret_primary = &tcp_secret_one;
3596         tcp_secret_retiring = &tcp_secret_two;
3597         tcp_secret_secondary = &tcp_secret_two;
3598 }