linux/net/ipv4/tcp.c
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   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/inet_common.h>
 274#include <net/tcp.h>
 275#include <net/xfrm.h>
 276#include <net/ip.h>
 277#include <net/netdma.h>
 278#include <net/sock.h>
 279
 280#include <asm/uaccess.h>
 281#include <asm/ioctls.h>
 282
 283int sysctl_tcp_fin_timeout __read_mostly = TCP_FIN_TIMEOUT;
 284
 285struct percpu_counter tcp_orphan_count;
 286EXPORT_SYMBOL_GPL(tcp_orphan_count);
 287
 288int sysctl_tcp_wmem[3] __read_mostly;
 289int sysctl_tcp_rmem[3] __read_mostly;
 290
 291EXPORT_SYMBOL(sysctl_tcp_rmem);
 292EXPORT_SYMBOL(sysctl_tcp_wmem);
 293
 294atomic_long_t tcp_memory_allocated;     /* Current allocated memory. */
 295EXPORT_SYMBOL(tcp_memory_allocated);
 296
 297/*
 298 * Current number of TCP sockets.
 299 */
 300struct percpu_counter tcp_sockets_allocated;
 301EXPORT_SYMBOL(tcp_sockets_allocated);
 302
 303/*
 304 * TCP splice context
 305 */
 306struct tcp_splice_state {
 307        struct pipe_inode_info *pipe;
 308        size_t len;
 309        unsigned int flags;
 310};
 311
 312/*
 313 * Pressure flag: try to collapse.
 314 * Technical note: it is used by multiple contexts non atomically.
 315 * All the __sk_mem_schedule() is of this nature: accounting
 316 * is strict, actions are advisory and have some latency.
 317 */
 318int tcp_memory_pressure __read_mostly;
 319EXPORT_SYMBOL(tcp_memory_pressure);
 320
 321void tcp_enter_memory_pressure(struct sock *sk)
 322{
 323        if (!tcp_memory_pressure) {
 324                NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMEMORYPRESSURES);
 325                tcp_memory_pressure = 1;
 326        }
 327}
 328EXPORT_SYMBOL(tcp_enter_memory_pressure);
 329
 330/* Convert seconds to retransmits based on initial and max timeout */
 331static u8 secs_to_retrans(int seconds, int timeout, int rto_max)
 332{
 333        u8 res = 0;
 334
 335        if (seconds > 0) {
 336                int period = timeout;
 337
 338                res = 1;
 339                while (seconds > period && res < 255) {
 340                        res++;
 341                        timeout <<= 1;
 342                        if (timeout > rto_max)
 343                                timeout = rto_max;
 344                        period += timeout;
 345                }
 346        }
 347        return res;
 348}
 349
 350/* Convert retransmits to seconds based on initial and max timeout */
 351static int retrans_to_secs(u8 retrans, int timeout, int rto_max)
 352{
 353        int period = 0;
 354
 355        if (retrans > 0) {
 356                period = timeout;
 357                while (--retrans) {
 358                        timeout <<= 1;
 359                        if (timeout > rto_max)
 360                                timeout = rto_max;
 361                        period += timeout;
 362                }
 363        }
 364        return period;
 365}
 366
 367/* Address-family independent initialization for a tcp_sock.
 368 *
 369 * NOTE: A lot of things set to zero explicitly by call to
 370 *       sk_alloc() so need not be done here.
 371 */
 372void tcp_init_sock(struct sock *sk)
 373{
 374        struct inet_connection_sock *icsk = inet_csk(sk);
 375        struct tcp_sock *tp = tcp_sk(sk);
 376
 377        skb_queue_head_init(&tp->out_of_order_queue);
 378        tcp_init_xmit_timers(sk);
 379        tcp_prequeue_init(tp);
 380        INIT_LIST_HEAD(&tp->tsq_node);
 381
 382        icsk->icsk_rto = TCP_TIMEOUT_INIT;
 383        tp->mdev = TCP_TIMEOUT_INIT;
 384
 385        /* So many TCP implementations out there (incorrectly) count the
 386         * initial SYN frame in their delayed-ACK and congestion control
 387         * algorithms that we must have the following bandaid to talk
 388         * efficiently to them.  -DaveM
 389         */
 390        tp->snd_cwnd = TCP_INIT_CWND;
 391
 392        /* See draft-stevens-tcpca-spec-01 for discussion of the
 393         * initialization of these values.
 394         */
 395        tp->snd_ssthresh = TCP_INFINITE_SSTHRESH;
 396        tp->snd_cwnd_clamp = ~0;
 397        tp->mss_cache = TCP_MSS_DEFAULT;
 398
 399        tp->reordering = sysctl_tcp_reordering;
 400        tcp_enable_early_retrans(tp);
 401        icsk->icsk_ca_ops = &tcp_init_congestion_ops;
 402
 403        sk->sk_state = TCP_CLOSE;
 404
 405        sk->sk_write_space = sk_stream_write_space;
 406        sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
 407
 408        icsk->icsk_sync_mss = tcp_sync_mss;
 409
 410        /* TCP Cookie Transactions */
 411        if (sysctl_tcp_cookie_size > 0) {
 412                /* Default, cookies without s_data_payload. */
 413                tp->cookie_values =
 414                        kzalloc(sizeof(*tp->cookie_values),
 415                                sk->sk_allocation);
 416                if (tp->cookie_values != NULL)
 417                        kref_init(&tp->cookie_values->kref);
 418        }
 419        /* Presumed zeroed, in order of appearance:
 420         *      cookie_in_always, cookie_out_never,
 421         *      s_data_constant, s_data_in, s_data_out
 422         */
 423        sk->sk_sndbuf = sysctl_tcp_wmem[1];
 424        sk->sk_rcvbuf = sysctl_tcp_rmem[1];
 425
 426        local_bh_disable();
 427        sock_update_memcg(sk);
 428        sk_sockets_allocated_inc(sk);
 429        local_bh_enable();
 430}
 431EXPORT_SYMBOL(tcp_init_sock);
 432
 433/*
 434 *      Wait for a TCP event.
 435 *
 436 *      Note that we don't need to lock the socket, as the upper poll layers
 437 *      take care of normal races (between the test and the event) and we don't
 438 *      go look at any of the socket buffers directly.
 439 */
 440unsigned int tcp_poll(struct file *file, struct socket *sock, poll_table *wait)
 441{
 442        unsigned int mask;
 443        struct sock *sk = sock->sk;
 444        const struct tcp_sock *tp = tcp_sk(sk);
 445
 446        sock_poll_wait(file, sk_sleep(sk), wait);
 447        if (sk->sk_state == TCP_LISTEN)
 448                return inet_csk_listen_poll(sk);
 449
 450        /* Socket is not locked. We are protected from async events
 451         * by poll logic and correct handling of state changes
 452         * made by other threads is impossible in any case.
 453         */
 454
 455        mask = 0;
 456
 457        /*
 458         * POLLHUP is certainly not done right. But poll() doesn't
 459         * have a notion of HUP in just one direction, and for a
 460         * socket the read side is more interesting.
 461         *
 462         * Some poll() documentation says that POLLHUP is incompatible
 463         * with the POLLOUT/POLLWR flags, so somebody should check this
 464         * all. But careful, it tends to be safer to return too many
 465         * bits than too few, and you can easily break real applications
 466         * if you don't tell them that something has hung up!
 467         *
 468         * Check-me.
 469         *
 470         * Check number 1. POLLHUP is _UNMASKABLE_ event (see UNIX98 and
 471         * our fs/select.c). It means that after we received EOF,
 472         * poll always returns immediately, making impossible poll() on write()
 473         * in state CLOSE_WAIT. One solution is evident --- to set POLLHUP
 474         * if and only if shutdown has been made in both directions.
 475         * Actually, it is interesting to look how Solaris and DUX
 476         * solve this dilemma. I would prefer, if POLLHUP were maskable,
 477         * then we could set it on SND_SHUTDOWN. BTW examples given
 478         * in Stevens' books assume exactly this behaviour, it explains
 479         * why POLLHUP is incompatible with POLLOUT.    --ANK
 480         *
 481         * NOTE. Check for TCP_CLOSE is added. The goal is to prevent
 482         * blocking on fresh not-connected or disconnected socket. --ANK
 483         */
 484        if (sk->sk_shutdown == SHUTDOWN_MASK || sk->sk_state == TCP_CLOSE)
 485                mask |= POLLHUP;
 486        if (sk->sk_shutdown & RCV_SHUTDOWN)
 487                mask |= POLLIN | POLLRDNORM | POLLRDHUP;
 488
 489        /* Connected or passive Fast Open socket? */
 490        if (sk->sk_state != TCP_SYN_SENT &&
 491            (sk->sk_state != TCP_SYN_RECV || tp->fastopen_rsk != NULL)) {
 492                int target = sock_rcvlowat(sk, 0, INT_MAX);
 493
 494                if (tp->urg_seq == tp->copied_seq &&
 495                    !sock_flag(sk, SOCK_URGINLINE) &&
 496                    tp->urg_data)
 497                        target++;
 498
 499                /* Potential race condition. If read of tp below will
 500                 * escape above sk->sk_state, we can be illegally awaken
 501                 * in SYN_* states. */
 502                if (tp->rcv_nxt - tp->copied_seq >= target)
 503                        mask |= POLLIN | POLLRDNORM;
 504
 505                if (!(sk->sk_shutdown & SEND_SHUTDOWN)) {
 506                        if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk)) {
 507                                mask |= POLLOUT | POLLWRNORM;
 508                        } else {  /* send SIGIO later */
 509                                set_bit(SOCK_ASYNC_NOSPACE,
 510                                        &sk->sk_socket->flags);
 511                                set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
 512
 513                                /* Race breaker. If space is freed after
 514                                 * wspace test but before the flags are set,
 515                                 * IO signal will be lost.
 516                                 */
 517                                if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk))
 518                                        mask |= POLLOUT | POLLWRNORM;
 519                        }
 520                } else
 521                        mask |= POLLOUT | POLLWRNORM;
 522
 523                if (tp->urg_data & TCP_URG_VALID)
 524                        mask |= POLLPRI;
 525        }
 526        /* This barrier is coupled with smp_wmb() in tcp_reset() */
 527        smp_rmb();
 528        if (sk->sk_err)
 529                mask |= POLLERR;
 530
 531        return mask;
 532}
 533EXPORT_SYMBOL(tcp_poll);
 534
 535int tcp_ioctl(struct sock *sk, int cmd, unsigned long arg)
 536{
 537        struct tcp_sock *tp = tcp_sk(sk);
 538        int answ;
 539
 540        switch (cmd) {
 541        case SIOCINQ:
 542                if (sk->sk_state == TCP_LISTEN)
 543                        return -EINVAL;
 544
 545                lock_sock(sk);
 546                if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
 547                        answ = 0;
 548                else if (sock_flag(sk, SOCK_URGINLINE) ||
 549                         !tp->urg_data ||
 550                         before(tp->urg_seq, tp->copied_seq) ||
 551                         !before(tp->urg_seq, tp->rcv_nxt)) {
 552
 553                        answ = tp->rcv_nxt - tp->copied_seq;
 554
 555                        /* Subtract 1, if FIN was received */
 556                        if (answ && sock_flag(sk, SOCK_DONE))
 557                                answ--;
 558                } else
 559                        answ = tp->urg_seq - tp->copied_seq;
 560                release_sock(sk);
 561                break;
 562        case SIOCATMARK:
 563                answ = tp->urg_data && tp->urg_seq == tp->copied_seq;
 564                break;
 565        case SIOCOUTQ:
 566                if (sk->sk_state == TCP_LISTEN)
 567                        return -EINVAL;
 568
 569                if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
 570                        answ = 0;
 571                else
 572                        answ = tp->write_seq - tp->snd_una;
 573                break;
 574        case SIOCOUTQNSD:
 575                if (sk->sk_state == TCP_LISTEN)
 576                        return -EINVAL;
 577
 578                if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
 579                        answ = 0;
 580                else
 581                        answ = tp->write_seq - tp->snd_nxt;
 582                break;
 583        default:
 584                return -ENOIOCTLCMD;
 585        }
 586
 587        return put_user(answ, (int __user *)arg);
 588}
 589EXPORT_SYMBOL(tcp_ioctl);
 590
 591static inline void tcp_mark_push(struct tcp_sock *tp, struct sk_buff *skb)
 592{
 593        TCP_SKB_CB(skb)->tcp_flags |= TCPHDR_PSH;
 594        tp->pushed_seq = tp->write_seq;
 595}
 596
 597static inline bool forced_push(const struct tcp_sock *tp)
 598{
 599        return after(tp->write_seq, tp->pushed_seq + (tp->max_window >> 1));
 600}
 601
 602static inline void skb_entail(struct sock *sk, struct sk_buff *skb)
 603{
 604        struct tcp_sock *tp = tcp_sk(sk);
 605        struct tcp_skb_cb *tcb = TCP_SKB_CB(skb);
 606
 607        skb->csum    = 0;
 608        tcb->seq     = tcb->end_seq = tp->write_seq;
 609        tcb->tcp_flags = TCPHDR_ACK;
 610        tcb->sacked  = 0;
 611        skb_header_release(skb);
 612        tcp_add_write_queue_tail(sk, skb);
 613        sk->sk_wmem_queued += skb->truesize;
 614        sk_mem_charge(sk, skb->truesize);
 615        if (tp->nonagle & TCP_NAGLE_PUSH)
 616                tp->nonagle &= ~TCP_NAGLE_PUSH;
 617}
 618
 619static inline void tcp_mark_urg(struct tcp_sock *tp, int flags)
 620{
 621        if (flags & MSG_OOB)
 622                tp->snd_up = tp->write_seq;
 623}
 624
 625static inline void tcp_push(struct sock *sk, int flags, int mss_now,
 626                            int nonagle)
 627{
 628        if (tcp_send_head(sk)) {
 629                struct tcp_sock *tp = tcp_sk(sk);
 630
 631                if (!(flags & MSG_MORE) || forced_push(tp))
 632                        tcp_mark_push(tp, tcp_write_queue_tail(sk));
 633
 634                tcp_mark_urg(tp, flags);
 635                __tcp_push_pending_frames(sk, mss_now,
 636                                          (flags & MSG_MORE) ? TCP_NAGLE_CORK : nonagle);
 637        }
 638}
 639
 640static int tcp_splice_data_recv(read_descriptor_t *rd_desc, struct sk_buff *skb,
 641                                unsigned int offset, size_t len)
 642{
 643        struct tcp_splice_state *tss = rd_desc->arg.data;
 644        int ret;
 645
 646        ret = skb_splice_bits(skb, offset, tss->pipe, min(rd_desc->count, len),
 647                              tss->flags);
 648        if (ret > 0)
 649                rd_desc->count -= ret;
 650        return ret;
 651}
 652
 653static int __tcp_splice_read(struct sock *sk, struct tcp_splice_state *tss)
 654{
 655        /* Store TCP splice context information in read_descriptor_t. */
 656        read_descriptor_t rd_desc = {
 657                .arg.data = tss,
 658                .count    = tss->len,
 659        };
 660
 661        return tcp_read_sock(sk, &rd_desc, tcp_splice_data_recv);
 662}
 663
 664/**
 665 *  tcp_splice_read - splice data from TCP socket to a pipe
 666 * @sock:       socket to splice from
 667 * @ppos:       position (not valid)
 668 * @pipe:       pipe to splice to
 669 * @len:        number of bytes to splice
 670 * @flags:      splice modifier flags
 671 *
 672 * Description:
 673 *    Will read pages from given socket and fill them into a pipe.
 674 *
 675 **/
 676ssize_t tcp_splice_read(struct socket *sock, loff_t *ppos,
 677                        struct pipe_inode_info *pipe, size_t len,
 678                        unsigned int flags)
 679{
 680        struct sock *sk = sock->sk;
 681        struct tcp_splice_state tss = {
 682                .pipe = pipe,
 683                .len = len,
 684                .flags = flags,
 685        };
 686        long timeo;
 687        ssize_t spliced;
 688        int ret;
 689
 690        sock_rps_record_flow(sk);
 691        /*
 692         * We can't seek on a socket input
 693         */
 694        if (unlikely(*ppos))
 695                return -ESPIPE;
 696
 697        ret = spliced = 0;
 698
 699        lock_sock(sk);
 700
 701        timeo = sock_rcvtimeo(sk, sock->file->f_flags & O_NONBLOCK);
 702        while (tss.len) {
 703                ret = __tcp_splice_read(sk, &tss);
 704                if (ret < 0)
 705                        break;
 706                else if (!ret) {
 707                        if (spliced)
 708                                break;
 709                        if (sock_flag(sk, SOCK_DONE))
 710                                break;
 711                        if (sk->sk_err) {
 712                                ret = sock_error(sk);
 713                                break;
 714                        }
 715                        if (sk->sk_shutdown & RCV_SHUTDOWN)
 716                                break;
 717                        if (sk->sk_state == TCP_CLOSE) {
 718                                /*
 719                                 * This occurs when user tries to read
 720                                 * from never connected socket.
 721                                 */
 722                                if (!sock_flag(sk, SOCK_DONE))
 723                                        ret = -ENOTCONN;
 724                                break;
 725                        }
 726                        if (!timeo) {
 727                                ret = -EAGAIN;
 728                                break;
 729                        }
 730                        sk_wait_data(sk, &timeo);
 731                        if (signal_pending(current)) {
 732                                ret = sock_intr_errno(timeo);
 733                                break;
 734                        }
 735                        continue;
 736                }
 737                tss.len -= ret;
 738                spliced += ret;
 739
 740                if (!timeo)
 741                        break;
 742                release_sock(sk);
 743                lock_sock(sk);
 744
 745                if (sk->sk_err || sk->sk_state == TCP_CLOSE ||
 746                    (sk->sk_shutdown & RCV_SHUTDOWN) ||
 747                    signal_pending(current))
 748                        break;
 749        }
 750
 751        release_sock(sk);
 752
 753        if (spliced)
 754                return spliced;
 755
 756        return ret;
 757}
 758EXPORT_SYMBOL(tcp_splice_read);
 759
 760struct sk_buff *sk_stream_alloc_skb(struct sock *sk, int size, gfp_t gfp)
 761{
 762        struct sk_buff *skb;
 763
 764        /* The TCP header must be at least 32-bit aligned.  */
 765        size = ALIGN(size, 4);
 766
 767        skb = alloc_skb_fclone(size + sk->sk_prot->max_header, gfp);
 768        if (skb) {
 769                if (sk_wmem_schedule(sk, skb->truesize)) {
 770                        skb_reserve(skb, sk->sk_prot->max_header);
 771                        /*
 772                         * Make sure that we have exactly size bytes
 773                         * available to the caller, no more, no less.
 774                         */
 775                        skb->avail_size = size;
 776                        return skb;
 777                }
 778                __kfree_skb(skb);
 779        } else {
 780                sk->sk_prot->enter_memory_pressure(sk);
 781                sk_stream_moderate_sndbuf(sk);
 782        }
 783        return NULL;
 784}
 785
 786static unsigned int tcp_xmit_size_goal(struct sock *sk, u32 mss_now,
 787                                       int large_allowed)
 788{
 789        struct tcp_sock *tp = tcp_sk(sk);
 790        u32 xmit_size_goal, old_size_goal;
 791
 792        xmit_size_goal = mss_now;
 793
 794        if (large_allowed && sk_can_gso(sk)) {
 795                xmit_size_goal = ((sk->sk_gso_max_size - 1) -
 796                                  inet_csk(sk)->icsk_af_ops->net_header_len -
 797                                  inet_csk(sk)->icsk_ext_hdr_len -
 798                                  tp->tcp_header_len);
 799
 800                /* TSQ : try to have two TSO segments in flight */
 801                xmit_size_goal = min_t(u32, xmit_size_goal,
 802                                       sysctl_tcp_limit_output_bytes >> 1);
 803
 804                xmit_size_goal = tcp_bound_to_half_wnd(tp, xmit_size_goal);
 805
 806                /* We try hard to avoid divides here */
 807                old_size_goal = tp->xmit_size_goal_segs * mss_now;
 808
 809                if (likely(old_size_goal <= xmit_size_goal &&
 810                           old_size_goal + mss_now > xmit_size_goal)) {
 811                        xmit_size_goal = old_size_goal;
 812                } else {
 813                        tp->xmit_size_goal_segs =
 814                                min_t(u16, xmit_size_goal / mss_now,
 815                                      sk->sk_gso_max_segs);
 816                        xmit_size_goal = tp->xmit_size_goal_segs * mss_now;
 817                }
 818        }
 819
 820        return max(xmit_size_goal, mss_now);
 821}
 822
 823static int tcp_send_mss(struct sock *sk, int *size_goal, int flags)
 824{
 825        int mss_now;
 826
 827        mss_now = tcp_current_mss(sk);
 828        *size_goal = tcp_xmit_size_goal(sk, mss_now, !(flags & MSG_OOB));
 829
 830        return mss_now;
 831}
 832
 833static ssize_t do_tcp_sendpages(struct sock *sk, struct page *page, int offset,
 834                                size_t size, int flags)
 835{
 836        struct tcp_sock *tp = tcp_sk(sk);
 837        int mss_now, size_goal;
 838        int err;
 839        ssize_t copied;
 840        long timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
 841
 842        /* Wait for a connection to finish. One exception is TCP Fast Open
 843         * (passive side) where data is allowed to be sent before a connection
 844         * is fully established.
 845         */
 846        if (((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) &&
 847            !tcp_passive_fastopen(sk)) {
 848                if ((err = sk_stream_wait_connect(sk, &timeo)) != 0)
 849                        goto out_err;
 850        }
 851
 852        clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
 853
 854        mss_now = tcp_send_mss(sk, &size_goal, flags);
 855        copied = 0;
 856
 857        err = -EPIPE;
 858        if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
 859                goto out_err;
 860
 861        while (size > 0) {
 862                struct sk_buff *skb = tcp_write_queue_tail(sk);
 863                int copy, i;
 864                bool can_coalesce;
 865
 866                if (!tcp_send_head(sk) || (copy = size_goal - skb->len) <= 0) {
 867new_segment:
 868                        if (!sk_stream_memory_free(sk))
 869                                goto wait_for_sndbuf;
 870
 871                        skb = sk_stream_alloc_skb(sk, 0, sk->sk_allocation);
 872                        if (!skb)
 873                                goto wait_for_memory;
 874
 875                        skb_entail(sk, skb);
 876                        copy = size_goal;
 877                }
 878
 879                if (copy > size)
 880                        copy = size;
 881
 882                i = skb_shinfo(skb)->nr_frags;
 883                can_coalesce = skb_can_coalesce(skb, i, page, offset);
 884                if (!can_coalesce && i >= MAX_SKB_FRAGS) {
 885                        tcp_mark_push(tp, skb);
 886                        goto new_segment;
 887                }
 888                if (!sk_wmem_schedule(sk, copy))
 889                        goto wait_for_memory;
 890
 891                if (can_coalesce) {
 892                        skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy);
 893                } else {
 894                        get_page(page);
 895                        skb_fill_page_desc(skb, i, page, offset, copy);
 896                }
 897
 898                skb->len += copy;
 899                skb->data_len += copy;
 900                skb->truesize += copy;
 901                sk->sk_wmem_queued += copy;
 902                sk_mem_charge(sk, copy);
 903                skb->ip_summed = CHECKSUM_PARTIAL;
 904                tp->write_seq += copy;
 905                TCP_SKB_CB(skb)->end_seq += copy;
 906                skb_shinfo(skb)->gso_segs = 0;
 907
 908                if (!copied)
 909                        TCP_SKB_CB(skb)->tcp_flags &= ~TCPHDR_PSH;
 910
 911                copied += copy;
 912                offset += copy;
 913                if (!(size -= copy))
 914                        goto out;
 915
 916                if (skb->len < size_goal || (flags & MSG_OOB))
 917                        continue;
 918
 919                if (forced_push(tp)) {
 920                        tcp_mark_push(tp, skb);
 921                        __tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH);
 922                } else if (skb == tcp_send_head(sk))
 923                        tcp_push_one(sk, mss_now);
 924                continue;
 925
 926wait_for_sndbuf:
 927                set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
 928wait_for_memory:
 929                tcp_push(sk, flags & ~MSG_MORE, mss_now, TCP_NAGLE_PUSH);
 930
 931                if ((err = sk_stream_wait_memory(sk, &timeo)) != 0)
 932                        goto do_error;
 933
 934                mss_now = tcp_send_mss(sk, &size_goal, flags);
 935        }
 936
 937out:
 938        if (copied && !(flags & MSG_SENDPAGE_NOTLAST))
 939                tcp_push(sk, flags, mss_now, tp->nonagle);
 940        return copied;
 941
 942do_error:
 943        if (copied)
 944                goto out;
 945out_err:
 946        return sk_stream_error(sk, flags, err);
 947}
 948
 949int tcp_sendpage(struct sock *sk, struct page *page, int offset,
 950                 size_t size, int flags)
 951{
 952        ssize_t res;
 953
 954        if (!(sk->sk_route_caps & NETIF_F_SG) ||
 955            !(sk->sk_route_caps & NETIF_F_ALL_CSUM))
 956                return sock_no_sendpage(sk->sk_socket, page, offset, size,
 957                                        flags);
 958
 959        lock_sock(sk);
 960        res = do_tcp_sendpages(sk, page, offset, size, flags);
 961        release_sock(sk);
 962        return res;
 963}
 964EXPORT_SYMBOL(tcp_sendpage);
 965
 966static inline int select_size(const struct sock *sk, bool sg)
 967{
 968        const struct tcp_sock *tp = tcp_sk(sk);
 969        int tmp = tp->mss_cache;
 970
 971        if (sg) {
 972                if (sk_can_gso(sk)) {
 973                        /* Small frames wont use a full page:
 974                         * Payload will immediately follow tcp header.
 975                         */
 976                        tmp = SKB_WITH_OVERHEAD(2048 - MAX_TCP_HEADER);
 977                } else {
 978                        int pgbreak = SKB_MAX_HEAD(MAX_TCP_HEADER);
 979
 980                        if (tmp >= pgbreak &&
 981                            tmp <= pgbreak + (MAX_SKB_FRAGS - 1) * PAGE_SIZE)
 982                                tmp = pgbreak;
 983                }
 984        }
 985
 986        return tmp;
 987}
 988
 989void tcp_free_fastopen_req(struct tcp_sock *tp)
 990{
 991        if (tp->fastopen_req != NULL) {
 992                kfree(tp->fastopen_req);
 993                tp->fastopen_req = NULL;
 994        }
 995}
 996
 997static int tcp_sendmsg_fastopen(struct sock *sk, struct msghdr *msg, int *size)
 998{
 999        struct tcp_sock *tp = tcp_sk(sk);
1000        int err, flags;
1001
1002        if (!(sysctl_tcp_fastopen & TFO_CLIENT_ENABLE))
1003                return -EOPNOTSUPP;
1004        if (tp->fastopen_req != NULL)
1005                return -EALREADY; /* Another Fast Open is in progress */
1006
1007        tp->fastopen_req = kzalloc(sizeof(struct tcp_fastopen_request),
1008                                   sk->sk_allocation);
1009        if (unlikely(tp->fastopen_req == NULL))
1010                return -ENOBUFS;
1011        tp->fastopen_req->data = msg;
1012
1013        flags = (msg->msg_flags & MSG_DONTWAIT) ? O_NONBLOCK : 0;
1014        err = __inet_stream_connect(sk->sk_socket, msg->msg_name,
1015                                    msg->msg_namelen, flags);
1016        *size = tp->fastopen_req->copied;
1017        tcp_free_fastopen_req(tp);
1018        return err;
1019}
1020
1021int tcp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
1022                size_t size)
1023{
1024        struct iovec *iov;
1025        struct tcp_sock *tp = tcp_sk(sk);
1026        struct sk_buff *skb;
1027        int iovlen, flags, err, copied = 0;
1028        int mss_now = 0, size_goal, copied_syn = 0, offset = 0;
1029        bool sg;
1030        long timeo;
1031
1032        lock_sock(sk);
1033
1034        flags = msg->msg_flags;
1035        if (flags & MSG_FASTOPEN) {
1036                err = tcp_sendmsg_fastopen(sk, msg, &copied_syn);
1037                if (err == -EINPROGRESS && copied_syn > 0)
1038                        goto out;
1039                else if (err)
1040                        goto out_err;
1041                offset = copied_syn;
1042        }
1043
1044        timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
1045
1046        /* Wait for a connection to finish. One exception is TCP Fast Open
1047         * (passive side) where data is allowed to be sent before a connection
1048         * is fully established.
1049         */
1050        if (((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) &&
1051            !tcp_passive_fastopen(sk)) {
1052                if ((err = sk_stream_wait_connect(sk, &timeo)) != 0)
1053                        goto do_error;
1054        }
1055
1056        if (unlikely(tp->repair)) {
1057                if (tp->repair_queue == TCP_RECV_QUEUE) {
1058                        copied = tcp_send_rcvq(sk, msg, size);
1059                        goto out;
1060                }
1061
1062                err = -EINVAL;
1063                if (tp->repair_queue == TCP_NO_QUEUE)
1064                        goto out_err;
1065
1066                /* 'common' sending to sendq */
1067        }
1068
1069        /* This should be in poll */
1070        clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
1071
1072        mss_now = tcp_send_mss(sk, &size_goal, flags);
1073
1074        /* Ok commence sending. */
1075        iovlen = msg->msg_iovlen;
1076        iov = msg->msg_iov;
1077        copied = 0;
1078
1079        err = -EPIPE;
1080        if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
1081                goto out_err;
1082
1083        sg = !!(sk->sk_route_caps & NETIF_F_SG);
1084
1085        while (--iovlen >= 0) {
1086                size_t seglen = iov->iov_len;
1087                unsigned char __user *from = iov->iov_base;
1088
1089                iov++;
1090                if (unlikely(offset > 0)) {  /* Skip bytes copied in SYN */
1091                        if (offset >= seglen) {
1092                                offset -= seglen;
1093                                continue;
1094                        }
1095                        seglen -= offset;
1096                        from += offset;
1097                        offset = 0;
1098                }
1099
1100                while (seglen > 0) {
1101                        int copy = 0;
1102                        int max = size_goal;
1103
1104                        skb = tcp_write_queue_tail(sk);
1105                        if (tcp_send_head(sk)) {
1106                                if (skb->ip_summed == CHECKSUM_NONE)
1107                                        max = mss_now;
1108                                copy = max - skb->len;
1109                        }
1110
1111                        if (copy <= 0) {
1112new_segment:
1113                                /* Allocate new segment. If the interface is SG,
1114                                 * allocate skb fitting to single page.
1115                                 */
1116                                if (!sk_stream_memory_free(sk))
1117                                        goto wait_for_sndbuf;
1118
1119                                skb = sk_stream_alloc_skb(sk,
1120                                                          select_size(sk, sg),
1121                                                          sk->sk_allocation);
1122                                if (!skb)
1123                                        goto wait_for_memory;
1124
1125                                /*
1126                                 * Check whether we can use HW checksum.
1127                                 */
1128                                if (sk->sk_route_caps & NETIF_F_ALL_CSUM)
1129                                        skb->ip_summed = CHECKSUM_PARTIAL;
1130
1131                                skb_entail(sk, skb);
1132                                copy = size_goal;
1133                                max = size_goal;
1134                        }
1135
1136                        /* Try to append data to the end of skb. */
1137                        if (copy > seglen)
1138                                copy = seglen;
1139
1140                        /* Where to copy to? */
1141                        if (skb_availroom(skb) > 0) {
1142                                /* We have some space in skb head. Superb! */
1143                                copy = min_t(int, copy, skb_availroom(skb));
1144                                err = skb_add_data_nocache(sk, skb, from, copy);
1145                                if (err)
1146                                        goto do_fault;
1147                        } else {
1148                                bool merge = true;
1149                                int i = skb_shinfo(skb)->nr_frags;
1150                                struct page_frag *pfrag = sk_page_frag(sk);
1151
1152                                if (!sk_page_frag_refill(sk, pfrag))
1153                                        goto wait_for_memory;
1154
1155                                if (!skb_can_coalesce(skb, i, pfrag->page,
1156                                                      pfrag->offset)) {
1157                                        if (i == MAX_SKB_FRAGS || !sg) {
1158                                                tcp_mark_push(tp, skb);
1159                                                goto new_segment;
1160                                        }
1161                                        merge = false;
1162                                }
1163
1164                                copy = min_t(int, copy, pfrag->size - pfrag->offset);
1165
1166                                if (!sk_wmem_schedule(sk, copy))
1167                                        goto wait_for_memory;
1168
1169                                err = skb_copy_to_page_nocache(sk, from, skb,
1170                                                               pfrag->page,
1171                                                               pfrag->offset,
1172                                                               copy);
1173                                if (err)
1174                                        goto do_error;
1175
1176                                /* Update the skb. */
1177                                if (merge) {
1178                                        skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy);
1179                                } else {
1180                                        skb_fill_page_desc(skb, i, pfrag->page,
1181                                                           pfrag->offset, copy);
1182                                        get_page(pfrag->page);
1183                                }
1184                                pfrag->offset += copy;
1185                        }
1186
1187                        if (!copied)
1188                                TCP_SKB_CB(skb)->tcp_flags &= ~TCPHDR_PSH;
1189
1190                        tp->write_seq += copy;
1191                        TCP_SKB_CB(skb)->end_seq += copy;
1192                        skb_shinfo(skb)->gso_segs = 0;
1193
1194                        from += copy;
1195                        copied += copy;
1196                        if ((seglen -= copy) == 0 && iovlen == 0)
1197                                goto out;
1198
1199                        if (skb->len < max || (flags & MSG_OOB) || unlikely(tp->repair))
1200                                continue;
1201
1202                        if (forced_push(tp)) {
1203                                tcp_mark_push(tp, skb);
1204                                __tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH);
1205                        } else if (skb == tcp_send_head(sk))
1206                                tcp_push_one(sk, mss_now);
1207                        continue;
1208
1209wait_for_sndbuf:
1210                        set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
1211wait_for_memory:
1212                        if (copied)
1213                                tcp_push(sk, flags & ~MSG_MORE, mss_now, TCP_NAGLE_PUSH);
1214
1215                        if ((err = sk_stream_wait_memory(sk, &timeo)) != 0)
1216                                goto do_error;
1217
1218                        mss_now = tcp_send_mss(sk, &size_goal, flags);
1219                }
1220        }
1221
1222out:
1223        if (copied)
1224                tcp_push(sk, flags, mss_now, tp->nonagle);
1225        release_sock(sk);
1226        return copied + copied_syn;
1227
1228do_fault:
1229        if (!skb->len) {
1230                tcp_unlink_write_queue(skb, sk);
1231                /* It is the one place in all of TCP, except connection
1232                 * reset, where we can be unlinking the send_head.
1233                 */
1234                tcp_check_send_head(sk, skb);
1235                sk_wmem_free_skb(sk, skb);
1236        }
1237
1238do_error:
1239        if (copied + copied_syn)
1240                goto out;
1241out_err:
1242        err = sk_stream_error(sk, flags, err);
1243        release_sock(sk);
1244        return err;
1245}
1246EXPORT_SYMBOL(tcp_sendmsg);
1247
1248/*
1249 *      Handle reading urgent data. BSD has very simple semantics for
1250 *      this, no blocking and very strange errors 8)
1251 */
1252
1253static int tcp_recv_urg(struct sock *sk, struct msghdr *msg, int len, int flags)
1254{
1255        struct tcp_sock *tp = tcp_sk(sk);
1256
1257        /* No URG data to read. */
1258        if (sock_flag(sk, SOCK_URGINLINE) || !tp->urg_data ||
1259            tp->urg_data == TCP_URG_READ)
1260                return -EINVAL; /* Yes this is right ! */
1261
1262        if (sk->sk_state == TCP_CLOSE && !sock_flag(sk, SOCK_DONE))
1263                return -ENOTCONN;
1264
1265        if (tp->urg_data & TCP_URG_VALID) {
1266                int err = 0;
1267                char c = tp->urg_data;
1268
1269                if (!(flags & MSG_PEEK))
1270                        tp->urg_data = TCP_URG_READ;
1271
1272                /* Read urgent data. */
1273                msg->msg_flags |= MSG_OOB;
1274
1275                if (len > 0) {
1276                        if (!(flags & MSG_TRUNC))
1277                                err = memcpy_toiovec(msg->msg_iov, &c, 1);
1278                        len = 1;
1279                } else
1280                        msg->msg_flags |= MSG_TRUNC;
1281
1282                return err ? -EFAULT : len;
1283        }
1284
1285        if (sk->sk_state == TCP_CLOSE || (sk->sk_shutdown & RCV_SHUTDOWN))
1286                return 0;
1287
1288        /* Fixed the recv(..., MSG_OOB) behaviour.  BSD docs and
1289         * the available implementations agree in this case:
1290         * this call should never block, independent of the
1291         * blocking state of the socket.
1292         * Mike <pall@rz.uni-karlsruhe.de>
1293         */
1294        return -EAGAIN;
1295}
1296
1297static int tcp_peek_sndq(struct sock *sk, struct msghdr *msg, int len)
1298{
1299        struct sk_buff *skb;
1300        int copied = 0, err = 0;
1301
1302        /* XXX -- need to support SO_PEEK_OFF */
1303
1304        skb_queue_walk(&sk->sk_write_queue, skb) {
1305                err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, skb->len);
1306                if (err)
1307                        break;
1308
1309                copied += skb->len;
1310        }
1311
1312        return err ?: copied;
1313}
1314
1315/* Clean up the receive buffer for full frames taken by the user,
1316 * then send an ACK if necessary.  COPIED is the number of bytes
1317 * tcp_recvmsg has given to the user so far, it speeds up the
1318 * calculation of whether or not we must ACK for the sake of
1319 * a window update.
1320 */
1321void tcp_cleanup_rbuf(struct sock *sk, int copied)
1322{
1323        struct tcp_sock *tp = tcp_sk(sk);
1324        bool time_to_ack = false;
1325
1326        struct sk_buff *skb = skb_peek(&sk->sk_receive_queue);
1327
1328        WARN(skb && !before(tp->copied_seq, TCP_SKB_CB(skb)->end_seq),
1329             "cleanup rbuf bug: copied %X seq %X rcvnxt %X\n",
1330             tp->copied_seq, TCP_SKB_CB(skb)->end_seq, tp->rcv_nxt);
1331
1332        if (inet_csk_ack_scheduled(sk)) {
1333                const struct inet_connection_sock *icsk = inet_csk(sk);
1334                   /* Delayed ACKs frequently hit locked sockets during bulk
1335                    * receive. */
1336                if (icsk->icsk_ack.blocked ||
1337                    /* Once-per-two-segments ACK was not sent by tcp_input.c */
1338                    tp->rcv_nxt - tp->rcv_wup > icsk->icsk_ack.rcv_mss ||
1339                    /*
1340                     * If this read emptied read buffer, we send ACK, if
1341                     * connection is not bidirectional, user drained
1342                     * receive buffer and there was a small segment
1343                     * in queue.
1344                     */
1345                    (copied > 0 &&
1346                     ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED2) ||
1347                      ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED) &&
1348                       !icsk->icsk_ack.pingpong)) &&
1349                      !atomic_read(&sk->sk_rmem_alloc)))
1350                        time_to_ack = true;
1351        }
1352
1353        /* We send an ACK if we can now advertise a non-zero window
1354         * which has been raised "significantly".
1355         *
1356         * Even if window raised up to infinity, do not send window open ACK
1357         * in states, where we will not receive more. It is useless.
1358         */
1359        if (copied > 0 && !time_to_ack && !(sk->sk_shutdown & RCV_SHUTDOWN)) {
1360                __u32 rcv_window_now = tcp_receive_window(tp);
1361
1362                /* Optimize, __tcp_select_window() is not cheap. */
1363                if (2*rcv_window_now <= tp->window_clamp) {
1364                        __u32 new_window = __tcp_select_window(sk);
1365
1366                        /* Send ACK now, if this read freed lots of space
1367                         * in our buffer. Certainly, new_window is new window.
1368                         * We can advertise it now, if it is not less than current one.
1369                         * "Lots" means "at least twice" here.
1370                         */
1371                        if (new_window && new_window >= 2 * rcv_window_now)
1372                                time_to_ack = true;
1373                }
1374        }
1375        if (time_to_ack)
1376                tcp_send_ack(sk);
1377}
1378
1379static void tcp_prequeue_process(struct sock *sk)
1380{
1381        struct sk_buff *skb;
1382        struct tcp_sock *tp = tcp_sk(sk);
1383
1384        NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPPREQUEUED);
1385
1386        /* RX process wants to run with disabled BHs, though it is not
1387         * necessary */
1388        local_bh_disable();
1389        while ((skb = __skb_dequeue(&tp->ucopy.prequeue)) != NULL)
1390                sk_backlog_rcv(sk, skb);
1391        local_bh_enable();
1392
1393        /* Clear memory counter. */
1394        tp->ucopy.memory = 0;
1395}
1396
1397#ifdef CONFIG_NET_DMA
1398static void tcp_service_net_dma(struct sock *sk, bool wait)
1399{
1400        dma_cookie_t done, used;
1401        dma_cookie_t last_issued;
1402        struct tcp_sock *tp = tcp_sk(sk);
1403
1404        if (!tp->ucopy.dma_chan)
1405                return;
1406
1407        last_issued = tp->ucopy.dma_cookie;
1408        dma_async_memcpy_issue_pending(tp->ucopy.dma_chan);
1409
1410        do {
1411                if (dma_async_memcpy_complete(tp->ucopy.dma_chan,
1412                                              last_issued, &done,
1413                                              &used) == DMA_SUCCESS) {
1414                        /* Safe to free early-copied skbs now */
1415                        __skb_queue_purge(&sk->sk_async_wait_queue);
1416                        break;
1417                } else {
1418                        struct sk_buff *skb;
1419                        while ((skb = skb_peek(&sk->sk_async_wait_queue)) &&
1420                               (dma_async_is_complete(skb->dma_cookie, done,
1421                                                      used) == DMA_SUCCESS)) {
1422                                __skb_dequeue(&sk->sk_async_wait_queue);
1423                                kfree_skb(skb);
1424                        }
1425                }
1426        } while (wait);
1427}
1428#endif
1429
1430static struct sk_buff *tcp_recv_skb(struct sock *sk, u32 seq, u32 *off)
1431{
1432        struct sk_buff *skb;
1433        u32 offset;
1434
1435        while ((skb = skb_peek(&sk->sk_receive_queue)) != NULL) {
1436                offset = seq - TCP_SKB_CB(skb)->seq;
1437                if (tcp_hdr(skb)->syn)
1438                        offset--;
1439                if (offset < skb->len || tcp_hdr(skb)->fin) {
1440                        *off = offset;
1441                        return skb;
1442                }
1443                /* This looks weird, but this can happen if TCP collapsing
1444                 * splitted a fat GRO packet, while we released socket lock
1445                 * in skb_splice_bits()
1446                 */
1447                sk_eat_skb(sk, skb, false);
1448        }
1449        return NULL;
1450}
1451
1452/*
1453 * This routine provides an alternative to tcp_recvmsg() for routines
1454 * that would like to handle copying from skbuffs directly in 'sendfile'
1455 * fashion.
1456 * Note:
1457 *      - It is assumed that the socket was locked by the caller.
1458 *      - The routine does not block.
1459 *      - At present, there is no support for reading OOB data
1460 *        or for 'peeking' the socket using this routine
1461 *        (although both would be easy to implement).
1462 */
1463int tcp_read_sock(struct sock *sk, read_descriptor_t *desc,
1464                  sk_read_actor_t recv_actor)
1465{
1466        struct sk_buff *skb;
1467        struct tcp_sock *tp = tcp_sk(sk);
1468        u32 seq = tp->copied_seq;
1469        u32 offset;
1470        int copied = 0;
1471
1472        if (sk->sk_state == TCP_LISTEN)
1473                return -ENOTCONN;
1474        while ((skb = tcp_recv_skb(sk, seq, &offset)) != NULL) {
1475                if (offset < skb->len) {
1476                        int used;
1477                        size_t len;
1478
1479                        len = skb->len - offset;
1480                        /* Stop reading if we hit a patch of urgent data */
1481                        if (tp->urg_data) {
1482                                u32 urg_offset = tp->urg_seq - seq;
1483                                if (urg_offset < len)
1484                                        len = urg_offset;
1485                                if (!len)
1486                                        break;
1487                        }
1488                        used = recv_actor(desc, skb, offset, len);
1489                        if (used <= 0) {
1490                                if (!copied)
1491                                        copied = used;
1492                                break;
1493                        } else if (used <= len) {
1494                                seq += used;
1495                                copied += used;
1496                                offset += used;
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)
1505                                break;
1506                        /* TCP coalescing might have appended data to the skb.
1507                         * Try to splice more frags
1508                         */
1509                        if (offset + 1 != skb->len)
1510                                continue;
1511                }
1512                if (tcp_hdr(skb)->fin) {
1513                        sk_eat_skb(sk, skb, false);
1514                        ++seq;
1515                        break;
1516                }
1517                sk_eat_skb(sk, skb, false);
1518                if (!desc->count)
1519                        break;
1520                tp->copied_seq = seq;
1521        }
1522        tp->copied_seq = seq;
1523
1524        tcp_rcv_space_adjust(sk);
1525
1526        /* Clean up data we have read: This will do ACK frames. */
1527        if (copied > 0) {
1528                tcp_recv_skb(sk, seq, &offset);
1529                tcp_cleanup_rbuf(sk, copied);
1530        }
1531        return copied;
1532}
1533EXPORT_SYMBOL(tcp_read_sock);
1534
1535/*
1536 *      This routine copies from a sock struct into the user buffer.
1537 *
1538 *      Technical note: in 2.3 we work on _locked_ socket, so that
1539 *      tricks with *seq access order and skb->users are not required.
1540 *      Probably, code can be easily improved even more.
1541 */
1542
1543int tcp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
1544                size_t len, int nonblock, int flags, int *addr_len)
1545{
1546        struct tcp_sock *tp = tcp_sk(sk);
1547        int copied = 0;
1548        u32 peek_seq;
1549        u32 *seq;
1550        unsigned long used;
1551        int err;
1552        int target;             /* Read at least this many bytes */
1553        long timeo;
1554        struct task_struct *user_recv = NULL;
1555        bool copied_early = false;
1556        struct sk_buff *skb;
1557        u32 urg_hole = 0;
1558
1559        lock_sock(sk);
1560
1561        err = -ENOTCONN;
1562        if (sk->sk_state == TCP_LISTEN)
1563                goto out;
1564
1565        timeo = sock_rcvtimeo(sk, nonblock);
1566
1567        /* Urgent data needs to be handled specially. */
1568        if (flags & MSG_OOB)
1569                goto recv_urg;
1570
1571        if (unlikely(tp->repair)) {
1572                err = -EPERM;
1573                if (!(flags & MSG_PEEK))
1574                        goto out;
1575
1576                if (tp->repair_queue == TCP_SEND_QUEUE)
1577                        goto recv_sndq;
1578
1579                err = -EINVAL;
1580                if (tp->repair_queue == TCP_NO_QUEUE)
1581                        goto out;
1582
1583                /* 'common' recv queue MSG_PEEK-ing */
1584        }
1585
1586        seq = &tp->copied_seq;
1587        if (flags & MSG_PEEK) {
1588                peek_seq = tp->copied_seq;
1589                seq = &peek_seq;
1590        }
1591
1592        target = sock_rcvlowat(sk, flags & MSG_WAITALL, len);
1593
1594#ifdef CONFIG_NET_DMA
1595        tp->ucopy.dma_chan = NULL;
1596        preempt_disable();
1597        skb = skb_peek_tail(&sk->sk_receive_queue);
1598        {
1599                int available = 0;
1600
1601                if (skb)
1602                        available = TCP_SKB_CB(skb)->seq + skb->len - (*seq);
1603                if ((available < target) &&
1604                    (len > sysctl_tcp_dma_copybreak) && !(flags & MSG_PEEK) &&
1605                    !sysctl_tcp_low_latency &&
1606                    net_dma_find_channel()) {
1607                        preempt_enable_no_resched();
1608                        tp->ucopy.pinned_list =
1609                                        dma_pin_iovec_pages(msg->msg_iov, len);
1610                } else {
1611                        preempt_enable_no_resched();
1612                }
1613        }
1614#endif
1615
1616        do {
1617                u32 offset;
1618
1619                /* Are we at urgent data? Stop if we have read anything or have SIGURG pending. */
1620                if (tp->urg_data && tp->urg_seq == *seq) {
1621                        if (copied)
1622                                break;
1623                        if (signal_pending(current)) {
1624                                copied = timeo ? sock_intr_errno(timeo) : -EAGAIN;
1625                                break;
1626                        }
1627                }
1628
1629                /* Next get a buffer. */
1630
1631                skb_queue_walk(&sk->sk_receive_queue, skb) {
1632                        /* Now that we have two receive queues this
1633                         * shouldn't happen.
1634                         */
1635                        if (WARN(before(*seq, TCP_SKB_CB(skb)->seq),
1636                                 "recvmsg bug: copied %X seq %X rcvnxt %X fl %X\n",
1637                                 *seq, TCP_SKB_CB(skb)->seq, tp->rcv_nxt,
1638                                 flags))
1639                                break;
1640
1641                        offset = *seq - TCP_SKB_CB(skb)->seq;
1642                        if (tcp_hdr(skb)->syn)
1643                                offset--;
1644                        if (offset < skb->len)
1645                                goto found_ok_skb;
1646                        if (tcp_hdr(skb)->fin)
1647                                goto found_fin_ok;
1648                        WARN(!(flags & MSG_PEEK),
1649                             "recvmsg bug 2: copied %X seq %X rcvnxt %X fl %X\n",
1650                             *seq, TCP_SKB_CB(skb)->seq, tp->rcv_nxt, flags);
1651                }
1652
1653                /* Well, if we have backlog, try to process it now yet. */
1654
1655                if (copied >= target && !sk->sk_backlog.tail)
1656                        break;
1657
1658                if (copied) {
1659                        if (sk->sk_err ||
1660                            sk->sk_state == TCP_CLOSE ||
1661                            (sk->sk_shutdown & RCV_SHUTDOWN) ||
1662                            !timeo ||
1663                            signal_pending(current))
1664                                break;
1665                } else {
1666                        if (sock_flag(sk, SOCK_DONE))
1667                                break;
1668
1669                        if (sk->sk_err) {
1670                                copied = sock_error(sk);
1671                                break;
1672                        }
1673
1674                        if (sk->sk_shutdown & RCV_SHUTDOWN)
1675                                break;
1676
1677                        if (sk->sk_state == TCP_CLOSE) {
1678                                if (!sock_flag(sk, SOCK_DONE)) {
1679                                        /* This occurs when user tries to read
1680                                         * from never connected socket.
1681                                         */
1682                                        copied = -ENOTCONN;
1683                                        break;
1684                                }
1685                                break;
1686                        }
1687
1688                        if (!timeo) {
1689                                copied = -EAGAIN;
1690                                break;
1691                        }
1692
1693                        if (signal_pending(current)) {
1694                                copied = sock_intr_errno(timeo);
1695                                break;
1696                        }
1697                }
1698
1699                tcp_cleanup_rbuf(sk, copied);
1700
1701                if (!sysctl_tcp_low_latency && tp->ucopy.task == user_recv) {
1702                        /* Install new reader */
1703                        if (!user_recv && !(flags & (MSG_TRUNC | MSG_PEEK))) {
1704                                user_recv = current;
1705                                tp->ucopy.task = user_recv;
1706                                tp->ucopy.iov = msg->msg_iov;
1707                        }
1708
1709                        tp->ucopy.len = len;
1710
1711                        WARN_ON(tp->copied_seq != tp->rcv_nxt &&
1712                                !(flags & (MSG_PEEK | MSG_TRUNC)));
1713
1714                        /* Ugly... If prequeue is not empty, we have to
1715                         * process it before releasing socket, otherwise
1716                         * order will be broken at second iteration.
1717                         * More elegant solution is required!!!
1718                         *
1719                         * Look: we have the following (pseudo)queues:
1720                         *
1721                         * 1. packets in flight
1722                         * 2. backlog
1723                         * 3. prequeue
1724                         * 4. receive_queue
1725                         *
1726                         * Each queue can be processed only if the next ones
1727                         * are empty. At this point we have empty receive_queue.
1728                         * But prequeue _can_ be not empty after 2nd iteration,
1729                         * when we jumped to start of loop because backlog
1730                         * processing added something to receive_queue.
1731                         * We cannot release_sock(), because backlog contains
1732                         * packets arrived _after_ prequeued ones.
1733                         *
1734                         * Shortly, algorithm is clear --- to process all
1735                         * the queues in order. We could make it more directly,
1736                         * requeueing packets from backlog to prequeue, if
1737                         * is not empty. It is more elegant, but eats cycles,
1738                         * unfortunately.
1739                         */
1740                        if (!skb_queue_empty(&tp->ucopy.prequeue))
1741                                goto do_prequeue;
1742
1743                        /* __ Set realtime policy in scheduler __ */
1744                }
1745
1746#ifdef CONFIG_NET_DMA
1747                if (tp->ucopy.dma_chan) {
1748                        if (tp->rcv_wnd == 0 &&
1749                            !skb_queue_empty(&sk->sk_async_wait_queue)) {
1750                                tcp_service_net_dma(sk, true);
1751                                tcp_cleanup_rbuf(sk, copied);
1752                        } else
1753                                dma_async_memcpy_issue_pending(tp->ucopy.dma_chan);
1754                }
1755#endif
1756                if (copied >= target) {
1757                        /* Do not sleep, just process backlog. */
1758                        release_sock(sk);
1759                        lock_sock(sk);
1760                } else
1761                        sk_wait_data(sk, &timeo);
1762
1763#ifdef CONFIG_NET_DMA
1764                tcp_service_net_dma(sk, false);  /* Don't block */
1765                tp->ucopy.wakeup = 0;
1766#endif
1767
1768                if (user_recv) {
1769                        int chunk;
1770
1771                        /* __ Restore normal policy in scheduler __ */
1772
1773                        if ((chunk = len - tp->ucopy.len) != 0) {
1774                                NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMBACKLOG, chunk);
1775                                len -= chunk;
1776                                copied += chunk;
1777                        }
1778
1779                        if (tp->rcv_nxt == tp->copied_seq &&
1780                            !skb_queue_empty(&tp->ucopy.prequeue)) {
1781do_prequeue:
1782                                tcp_prequeue_process(sk);
1783
1784                                if ((chunk = len - tp->ucopy.len) != 0) {
1785                                        NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
1786                                        len -= chunk;
1787                                        copied += chunk;
1788                                }
1789                        }
1790                }
1791                if ((flags & MSG_PEEK) &&
1792                    (peek_seq - copied - urg_hole != tp->copied_seq)) {
1793                        net_dbg_ratelimited("TCP(%s:%d): Application bug, race in MSG_PEEK\n",
1794                                            current->comm,
1795                                            task_pid_nr(current));
1796                        peek_seq = tp->copied_seq;
1797                }
1798                continue;
1799
1800        found_ok_skb:
1801                /* Ok so how much can we use? */
1802                used = skb->len - offset;
1803                if (len < used)
1804                        used = len;
1805
1806                /* Do we have urgent data here? */
1807                if (tp->urg_data) {
1808                        u32 urg_offset = tp->urg_seq - *seq;
1809                        if (urg_offset < used) {
1810                                if (!urg_offset) {
1811                                        if (!sock_flag(sk, SOCK_URGINLINE)) {
1812                                                ++*seq;
1813                                                urg_hole++;
1814                                                offset++;
1815                                                used--;
1816                                                if (!used)
1817                                                        goto skip_copy;
1818                                        }
1819                                } else
1820                                        used = urg_offset;
1821                        }
1822                }
1823
1824                if (!(flags & MSG_TRUNC)) {
1825#ifdef CONFIG_NET_DMA
1826                        if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list)
1827                                tp->ucopy.dma_chan = net_dma_find_channel();
1828
1829                        if (tp->ucopy.dma_chan) {
1830                                tp->ucopy.dma_cookie = dma_skb_copy_datagram_iovec(
1831                                        tp->ucopy.dma_chan, skb, offset,
1832                                        msg->msg_iov, used,
1833                                        tp->ucopy.pinned_list);
1834
1835                                if (tp->ucopy.dma_cookie < 0) {
1836
1837                                        pr_alert("%s: dma_cookie < 0\n",
1838                                                 __func__);
1839
1840                                        /* Exception. Bailout! */
1841                                        if (!copied)
1842                                                copied = -EFAULT;
1843                                        break;
1844                                }
1845
1846                                dma_async_memcpy_issue_pending(tp->ucopy.dma_chan);
1847
1848                                if ((offset + used) == skb->len)
1849                                        copied_early = true;
1850
1851                        } else
1852#endif
1853                        {
1854                                err = skb_copy_datagram_iovec(skb, offset,
1855                                                msg->msg_iov, used);
1856                                if (err) {
1857                                        /* Exception. Bailout! */
1858                                        if (!copied)
1859                                                copied = -EFAULT;
1860                                        break;
1861                                }
1862                        }
1863                }
1864
1865                *seq += used;
1866                copied += used;
1867                len -= used;
1868
1869                tcp_rcv_space_adjust(sk);
1870
1871skip_copy:
1872                if (tp->urg_data && after(tp->copied_seq, tp->urg_seq)) {
1873                        tp->urg_data = 0;
1874                        tcp_fast_path_check(sk);
1875                }
1876                if (used + offset < skb->len)
1877                        continue;
1878
1879                if (tcp_hdr(skb)->fin)
1880                        goto found_fin_ok;
1881                if (!(flags & MSG_PEEK)) {
1882                        sk_eat_skb(sk, skb, copied_early);
1883                        copied_early = false;
1884                }
1885                continue;
1886
1887        found_fin_ok:
1888                /* Process the FIN. */
1889                ++*seq;
1890                if (!(flags & MSG_PEEK)) {
1891                        sk_eat_skb(sk, skb, copied_early);
1892                        copied_early = false;
1893                }
1894                break;
1895        } while (len > 0);
1896
1897        if (user_recv) {
1898                if (!skb_queue_empty(&tp->ucopy.prequeue)) {
1899                        int chunk;
1900
1901                        tp->ucopy.len = copied > 0 ? len : 0;
1902
1903                        tcp_prequeue_process(sk);
1904
1905                        if (copied > 0 && (chunk = len - tp->ucopy.len) != 0) {
1906                                NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
1907                                len -= chunk;
1908                                copied += chunk;
1909                        }
1910                }
1911
1912                tp->ucopy.task = NULL;
1913                tp->ucopy.len = 0;
1914        }
1915
1916#ifdef CONFIG_NET_DMA
1917        tcp_service_net_dma(sk, true);  /* Wait for queue to drain */
1918        tp->ucopy.dma_chan = NULL;
1919
1920        if (tp->ucopy.pinned_list) {
1921                dma_unpin_iovec_pages(tp->ucopy.pinned_list);
1922                tp->ucopy.pinned_list = NULL;
1923        }
1924#endif
1925
1926        /* According to UNIX98, msg_name/msg_namelen are ignored
1927         * on connected socket. I was just happy when found this 8) --ANK
1928         */
1929
1930        /* Clean up data we have read: This will do ACK frames. */
1931        tcp_cleanup_rbuf(sk, copied);
1932
1933        release_sock(sk);
1934        return copied;
1935
1936out:
1937        release_sock(sk);
1938        return err;
1939
1940recv_urg:
1941        err = tcp_recv_urg(sk, msg, len, flags);
1942        goto out;
1943
1944recv_sndq:
1945        err = tcp_peek_sndq(sk, msg, len);
1946        goto out;
1947}
1948EXPORT_SYMBOL(tcp_recvmsg);
1949
1950void tcp_set_state(struct sock *sk, int state)
1951{
1952        int oldstate = sk->sk_state;
1953
1954        switch (state) {
1955        case TCP_ESTABLISHED:
1956                if (oldstate != TCP_ESTABLISHED)
1957                        TCP_INC_STATS(sock_net(sk), TCP_MIB_CURRESTAB);
1958                break;
1959
1960        case TCP_CLOSE:
1961                if (oldstate == TCP_CLOSE_WAIT || oldstate == TCP_ESTABLISHED)
1962                        TCP_INC_STATS(sock_net(sk), TCP_MIB_ESTABRESETS);
1963
1964                sk->sk_prot->unhash(sk);
1965                if (inet_csk(sk)->icsk_bind_hash &&
1966                    !(sk->sk_userlocks & SOCK_BINDPORT_LOCK))
1967                        inet_put_port(sk);
1968                /* fall through */
1969        default:
1970                if (oldstate == TCP_ESTABLISHED)
1971                        TCP_DEC_STATS(sock_net(sk), TCP_MIB_CURRESTAB);
1972        }
1973
1974        /* Change state AFTER socket is unhashed to avoid closed
1975         * socket sitting in hash tables.
1976         */
1977        sk->sk_state = state;
1978
1979#ifdef STATE_TRACE
1980        SOCK_DEBUG(sk, "TCP sk=%p, State %s -> %s\n", sk, statename[oldstate], statename[state]);
1981#endif
1982}
1983EXPORT_SYMBOL_GPL(tcp_set_state);
1984
1985/*
1986 *      State processing on a close. This implements the state shift for
1987 *      sending our FIN frame. Note that we only send a FIN for some
1988 *      states. A shutdown() may have already sent the FIN, or we may be
1989 *      closed.
1990 */
1991
1992static const unsigned char new_state[16] = {
1993  /* current state:        new state:      action:      */
1994  /* (Invalid)          */ TCP_CLOSE,
1995  /* TCP_ESTABLISHED    */ TCP_FIN_WAIT1 | TCP_ACTION_FIN,
1996  /* TCP_SYN_SENT       */ TCP_CLOSE,
1997  /* TCP_SYN_RECV       */ TCP_FIN_WAIT1 | TCP_ACTION_FIN,
1998  /* TCP_FIN_WAIT1      */ TCP_FIN_WAIT1,
1999  /* TCP_FIN_WAIT2      */ TCP_FIN_WAIT2,
2000  /* TCP_TIME_WAIT      */ TCP_CLOSE,
2001  /* TCP_CLOSE          */ TCP_CLOSE,
2002  /* TCP_CLOSE_WAIT     */ TCP_LAST_ACK  | TCP_ACTION_FIN,
2003  /* TCP_LAST_ACK       */ TCP_LAST_ACK,
2004  /* TCP_LISTEN         */ TCP_CLOSE,
2005  /* TCP_CLOSING        */ TCP_CLOSING,
2006};
2007
2008static int tcp_close_state(struct sock *sk)
2009{
2010        int next = (int)new_state[sk->sk_state];
2011        int ns = next & TCP_STATE_MASK;
2012
2013        tcp_set_state(sk, ns);
2014
2015        return next & TCP_ACTION_FIN;
2016}
2017
2018/*
2019 *      Shutdown the sending side of a connection. Much like close except
2020 *      that we don't receive shut down or sock_set_flag(sk, SOCK_DEAD).
2021 */
2022
2023void tcp_shutdown(struct sock *sk, int how)
2024{
2025        /*      We need to grab some memory, and put together a FIN,
2026         *      and then put it into the queue to be sent.
2027         *              Tim MacKenzie(tym@dibbler.cs.monash.edu.au) 4 Dec '92.
2028         */
2029        if (!(how & SEND_SHUTDOWN))
2030                return;
2031
2032        /* If we've already sent a FIN, or it's a closed state, skip this. */
2033        if ((1 << sk->sk_state) &
2034            (TCPF_ESTABLISHED | TCPF_SYN_SENT |
2035             TCPF_SYN_RECV | TCPF_CLOSE_WAIT)) {
2036                /* Clear out any half completed packets.  FIN if needed. */
2037                if (tcp_close_state(sk))
2038                        tcp_send_fin(sk);
2039        }
2040}
2041EXPORT_SYMBOL(tcp_shutdown);
2042
2043bool tcp_check_oom(struct sock *sk, int shift)
2044{
2045        bool too_many_orphans, out_of_socket_memory;
2046
2047        too_many_orphans = tcp_too_many_orphans(sk, shift);
2048        out_of_socket_memory = tcp_out_of_memory(sk);
2049
2050        if (too_many_orphans)
2051                net_info_ratelimited("too many orphaned sockets\n");
2052        if (out_of_socket_memory)
2053                net_info_ratelimited("out of memory -- consider tuning tcp_mem\n");
2054        return too_many_orphans || out_of_socket_memory;
2055}
2056
2057void tcp_close(struct sock *sk, long timeout)
2058{
2059        struct sk_buff *skb;
2060        int data_was_unread = 0;
2061        int state;
2062
2063        lock_sock(sk);
2064        sk->sk_shutdown = SHUTDOWN_MASK;
2065
2066        if (sk->sk_state == TCP_LISTEN) {
2067                tcp_set_state(sk, TCP_CLOSE);
2068
2069                /* Special case. */
2070                inet_csk_listen_stop(sk);
2071
2072                goto adjudge_to_death;
2073        }
2074
2075        /*  We need to flush the recv. buffs.  We do this only on the
2076         *  descriptor close, not protocol-sourced closes, because the
2077         *  reader process may not have drained the data yet!
2078         */
2079        while ((skb = __skb_dequeue(&sk->sk_receive_queue)) != NULL) {
2080                u32 len = TCP_SKB_CB(skb)->end_seq - TCP_SKB_CB(skb)->seq -
2081                          tcp_hdr(skb)->fin;
2082                data_was_unread += len;
2083                __kfree_skb(skb);
2084        }
2085
2086        sk_mem_reclaim(sk);
2087
2088        /* If socket has been already reset (e.g. in tcp_reset()) - kill it. */
2089        if (sk->sk_state == TCP_CLOSE)
2090                goto adjudge_to_death;
2091
2092        /* As outlined in RFC 2525, section 2.17, we send a RST here because
2093         * data was lost. To witness the awful effects of the old behavior of
2094         * always doing a FIN, run an older 2.1.x kernel or 2.0.x, start a bulk
2095         * GET in an FTP client, suspend the process, wait for the client to
2096         * advertise a zero window, then kill -9 the FTP client, wheee...
2097         * Note: timeout is always zero in such a case.
2098         */
2099        if (unlikely(tcp_sk(sk)->repair)) {
2100                sk->sk_prot->disconnect(sk, 0);
2101        } else if (data_was_unread) {
2102                /* Unread data was tossed, zap the connection. */
2103                NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPABORTONCLOSE);
2104                tcp_set_state(sk, TCP_CLOSE);
2105                tcp_send_active_reset(sk, sk->sk_allocation);
2106        } else if (sock_flag(sk, SOCK_LINGER) && !sk->sk_lingertime) {
2107                /* Check zero linger _after_ checking for unread data. */
2108                sk->sk_prot->disconnect(sk, 0);
2109                NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPABORTONDATA);
2110        } else if (tcp_close_state(sk)) {
2111                /* We FIN if the application ate all the data before
2112                 * zapping the connection.
2113                 */
2114
2115                /* RED-PEN. Formally speaking, we have broken TCP state
2116                 * machine. State transitions:
2117                 *
2118                 * TCP_ESTABLISHED -> TCP_FIN_WAIT1
2119                 * TCP_SYN_RECV -> TCP_FIN_WAIT1 (forget it, it's impossible)
2120                 * TCP_CLOSE_WAIT -> TCP_LAST_ACK
2121                 *
2122                 * are legal only when FIN has been sent (i.e. in window),
2123                 * rather than queued out of window. Purists blame.
2124                 *
2125                 * F.e. "RFC state" is ESTABLISHED,
2126                 * if Linux state is FIN-WAIT-1, but FIN is still not sent.
2127                 *
2128                 * The visible declinations are that sometimes
2129                 * we enter time-wait state, when it is not required really
2130                 * (harmless), do not send active resets, when they are
2131                 * required by specs (TCP_ESTABLISHED, TCP_CLOSE_WAIT, when
2132                 * they look as CLOSING or LAST_ACK for Linux)
2133                 * Probably, I missed some more holelets.
2134                 *                                              --ANK
2135                 * XXX (TFO) - To start off we don't support SYN+ACK+FIN
2136                 * in a single packet! (May consider it later but will
2137                 * probably need API support or TCP_CORK SYN-ACK until
2138                 * data is written and socket is closed.)
2139                 */
2140                tcp_send_fin(sk);
2141        }
2142
2143        sk_stream_wait_close(sk, timeout);
2144
2145adjudge_to_death:
2146        state = sk->sk_state;
2147        sock_hold(sk);
2148        sock_orphan(sk);
2149
2150        /* It is the last release_sock in its life. It will remove backlog. */
2151        release_sock(sk);
2152
2153
2154        /* Now socket is owned by kernel and we acquire BH lock
2155           to finish close. No need to check for user refs.
2156         */
2157        local_bh_disable();
2158        bh_lock_sock(sk);
2159        WARN_ON(sock_owned_by_user(sk));
2160
2161        percpu_counter_inc(sk->sk_prot->orphan_count);
2162
2163        /* Have we already been destroyed by a softirq or backlog? */
2164        if (state != TCP_CLOSE && sk->sk_state == TCP_CLOSE)
2165                goto out;
2166
2167        /*      This is a (useful) BSD violating of the RFC. There is a
2168         *      problem with TCP as specified in that the other end could
2169         *      keep a socket open forever with no application left this end.
2170         *      We use a 3 minute timeout (about the same as BSD) then kill
2171         *      our end. If they send after that then tough - BUT: long enough
2172         *      that we won't make the old 4*rto = almost no time - whoops
2173         *      reset mistake.
2174         *
2175         *      Nope, it was not mistake. It is really desired behaviour
2176         *      f.e. on http servers, when such sockets are useless, but
2177         *      consume significant resources. Let's do it with special
2178         *      linger2 option.                                 --ANK
2179         */
2180
2181        if (sk->sk_state == TCP_FIN_WAIT2) {
2182                struct tcp_sock *tp = tcp_sk(sk);
2183                if (tp->linger2 < 0) {
2184                        tcp_set_state(sk, TCP_CLOSE);
2185                        tcp_send_active_reset(sk, GFP_ATOMIC);
2186                        NET_INC_STATS_BH(sock_net(sk),
2187                                        LINUX_MIB_TCPABORTONLINGER);
2188                } else {
2189                        const int tmo = tcp_fin_time(sk);
2190
2191                        if (tmo > TCP_TIMEWAIT_LEN) {
2192                                inet_csk_reset_keepalive_timer(sk,
2193                                                tmo - TCP_TIMEWAIT_LEN);
2194                        } else {
2195                                tcp_time_wait(sk, TCP_FIN_WAIT2, tmo);
2196                                goto out;
2197                        }
2198                }
2199        }
2200        if (sk->sk_state != TCP_CLOSE) {
2201                sk_mem_reclaim(sk);
2202                if (tcp_check_oom(sk, 0)) {
2203                        tcp_set_state(sk, TCP_CLOSE);
2204                        tcp_send_active_reset(sk, GFP_ATOMIC);
2205                        NET_INC_STATS_BH(sock_net(sk),
2206                                        LINUX_MIB_TCPABORTONMEMORY);
2207                }
2208        }
2209
2210        if (sk->sk_state == TCP_CLOSE) {
2211                struct request_sock *req = tcp_sk(sk)->fastopen_rsk;
2212                /* We could get here with a non-NULL req if the socket is
2213                 * aborted (e.g., closed with unread data) before 3WHS
2214                 * finishes.
2215                 */
2216                if (req != NULL)
2217                        reqsk_fastopen_remove(sk, req, false);
2218                inet_csk_destroy_sock(sk);
2219        }
2220        /* Otherwise, socket is reprieved until protocol close. */
2221
2222out:
2223        bh_unlock_sock(sk);
2224        local_bh_enable();
2225        sock_put(sk);
2226}
2227EXPORT_SYMBOL(tcp_close);
2228
2229/* These states need RST on ABORT according to RFC793 */
2230
2231static inline bool tcp_need_reset(int state)
2232{
2233        return (1 << state) &
2234               (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT | TCPF_FIN_WAIT1 |
2235                TCPF_FIN_WAIT2 | TCPF_SYN_RECV);
2236}
2237
2238int tcp_disconnect(struct sock *sk, int flags)
2239{
2240        struct inet_sock *inet = inet_sk(sk);
2241        struct inet_connection_sock *icsk = inet_csk(sk);
2242        struct tcp_sock *tp = tcp_sk(sk);
2243        int err = 0;
2244        int old_state = sk->sk_state;
2245
2246        if (old_state != TCP_CLOSE)
2247                tcp_set_state(sk, TCP_CLOSE);
2248
2249        /* ABORT function of RFC793 */
2250        if (old_state == TCP_LISTEN) {
2251                inet_csk_listen_stop(sk);
2252        } else if (unlikely(tp->repair)) {
2253                sk->sk_err = ECONNABORTED;
2254        } else if (tcp_need_reset(old_state) ||
2255                   (tp->snd_nxt != tp->write_seq &&
2256                    (1 << old_state) & (TCPF_CLOSING | TCPF_LAST_ACK))) {
2257                /* The last check adjusts for discrepancy of Linux wrt. RFC
2258                 * states
2259                 */
2260                tcp_send_active_reset(sk, gfp_any());
2261                sk->sk_err = ECONNRESET;
2262        } else if (old_state == TCP_SYN_SENT)
2263                sk->sk_err = ECONNRESET;
2264
2265        tcp_clear_xmit_timers(sk);
2266        __skb_queue_purge(&sk->sk_receive_queue);
2267        tcp_write_queue_purge(sk);
2268        __skb_queue_purge(&tp->out_of_order_queue);
2269#ifdef CONFIG_NET_DMA
2270        __skb_queue_purge(&sk->sk_async_wait_queue);
2271#endif
2272
2273        inet->inet_dport = 0;
2274
2275        if (!(sk->sk_userlocks & SOCK_BINDADDR_LOCK))
2276                inet_reset_saddr(sk);
2277
2278        sk->sk_shutdown = 0;
2279        sock_reset_flag(sk, SOCK_DONE);
2280        tp->srtt = 0;
2281        if ((tp->write_seq += tp->max_window + 2) == 0)
2282                tp->write_seq = 1;
2283        icsk->icsk_backoff = 0;
2284        tp->snd_cwnd = 2;
2285        icsk->icsk_probes_out = 0;
2286        tp->packets_out = 0;
2287        tp->snd_ssthresh = TCP_INFINITE_SSTHRESH;
2288        tp->snd_cwnd_cnt = 0;
2289        tp->bytes_acked = 0;
2290        tp->window_clamp = 0;
2291        tcp_set_ca_state(sk, TCP_CA_Open);
2292        tcp_clear_retrans(tp);
2293        inet_csk_delack_init(sk);
2294        tcp_init_send_head(sk);
2295        memset(&tp->rx_opt, 0, sizeof(tp->rx_opt));
2296        __sk_dst_reset(sk);
2297
2298        WARN_ON(inet->inet_num && !icsk->icsk_bind_hash);
2299
2300        sk->sk_error_report(sk);
2301        return err;
2302}
2303EXPORT_SYMBOL(tcp_disconnect);
2304
2305void tcp_sock_destruct(struct sock *sk)
2306{
2307        inet_sock_destruct(sk);
2308
2309        kfree(inet_csk(sk)->icsk_accept_queue.fastopenq);
2310}
2311
2312static inline bool tcp_can_repair_sock(const struct sock *sk)
2313{
2314        return capable(CAP_NET_ADMIN) &&
2315                ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_ESTABLISHED));
2316}
2317
2318static int tcp_repair_options_est(struct tcp_sock *tp,
2319                struct tcp_repair_opt __user *optbuf, unsigned int len)
2320{
2321        struct tcp_repair_opt opt;
2322
2323        while (len >= sizeof(opt)) {
2324                if (copy_from_user(&opt, optbuf, sizeof(opt)))
2325                        return -EFAULT;
2326
2327                optbuf++;
2328                len -= sizeof(opt);
2329
2330                switch (opt.opt_code) {
2331                case TCPOPT_MSS:
2332                        tp->rx_opt.mss_clamp = opt.opt_val;
2333                        break;
2334                case TCPOPT_WINDOW:
2335                        {
2336                                u16 snd_wscale = opt.opt_val & 0xFFFF;
2337                                u16 rcv_wscale = opt.opt_val >> 16;
2338
2339                                if (snd_wscale > 14 || rcv_wscale > 14)
2340                                        return -EFBIG;
2341
2342                                tp->rx_opt.snd_wscale = snd_wscale;
2343                                tp->rx_opt.rcv_wscale = rcv_wscale;
2344                                tp->rx_opt.wscale_ok = 1;
2345                        }
2346                        break;
2347                case TCPOPT_SACK_PERM:
2348                        if (opt.opt_val != 0)
2349                                return -EINVAL;
2350
2351                        tp->rx_opt.sack_ok |= TCP_SACK_SEEN;
2352                        if (sysctl_tcp_fack)
2353                                tcp_enable_fack(tp);
2354                        break;
2355                case TCPOPT_TIMESTAMP:
2356                        if (opt.opt_val != 0)
2357                                return -EINVAL;
2358
2359                        tp->rx_opt.tstamp_ok = 1;
2360                        break;
2361                }
2362        }
2363
2364        return 0;
2365}
2366
2367/*
2368 *      Socket option code for TCP.
2369 */
2370static int do_tcp_setsockopt(struct sock *sk, int level,
2371                int optname, char __user *optval, unsigned int optlen)
2372{
2373        struct tcp_sock *tp = tcp_sk(sk);
2374        struct inet_connection_sock *icsk = inet_csk(sk);
2375        int val;
2376        int err = 0;
2377
2378        /* These are data/string values, all the others are ints */
2379        switch (optname) {
2380        case TCP_CONGESTION: {
2381                char name[TCP_CA_NAME_MAX];
2382
2383                if (optlen < 1)
2384                        return -EINVAL;
2385
2386                val = strncpy_from_user(name, optval,
2387                                        min_t(long, TCP_CA_NAME_MAX-1, optlen));
2388                if (val < 0)
2389                        return -EFAULT;
2390                name[val] = 0;
2391
2392                lock_sock(sk);
2393                err = tcp_set_congestion_control(sk, name);
2394                release_sock(sk);
2395                return err;
2396        }
2397        case TCP_COOKIE_TRANSACTIONS: {
2398                struct tcp_cookie_transactions ctd;
2399                struct tcp_cookie_values *cvp = NULL;
2400
2401                if (sizeof(ctd) > optlen)
2402                        return -EINVAL;
2403                if (copy_from_user(&ctd, optval, sizeof(ctd)))
2404                        return -EFAULT;
2405
2406                if (ctd.tcpct_used > sizeof(ctd.tcpct_value) ||
2407                    ctd.tcpct_s_data_desired > TCP_MSS_DESIRED)
2408                        return -EINVAL;
2409
2410                if (ctd.tcpct_cookie_desired == 0) {
2411                        /* default to global value */
2412                } else if ((0x1 & ctd.tcpct_cookie_desired) ||
2413                           ctd.tcpct_cookie_desired > TCP_COOKIE_MAX ||
2414                           ctd.tcpct_cookie_desired < TCP_COOKIE_MIN) {
2415                        return -EINVAL;
2416                }
2417
2418                if (TCP_COOKIE_OUT_NEVER & ctd.tcpct_flags) {
2419                        /* Supercedes all other values */
2420                        lock_sock(sk);
2421                        if (tp->cookie_values != NULL) {
2422                                kref_put(&tp->cookie_values->kref,
2423                                         tcp_cookie_values_release);
2424                                tp->cookie_values = NULL;
2425                        }
2426                        tp->rx_opt.cookie_in_always = 0; /* false */
2427                        tp->rx_opt.cookie_out_never = 1; /* true */
2428                        release_sock(sk);
2429                        return err;
2430                }
2431
2432                /* Allocate ancillary memory before locking.
2433                 */
2434                if (ctd.tcpct_used > 0 ||
2435                    (tp->cookie_values == NULL &&
2436                     (sysctl_tcp_cookie_size > 0 ||
2437                      ctd.tcpct_cookie_desired > 0 ||
2438                      ctd.tcpct_s_data_desired > 0))) {
2439                        cvp = kzalloc(sizeof(*cvp) + ctd.tcpct_used,
2440                                      GFP_KERNEL);
2441                        if (cvp == NULL)
2442                                return -ENOMEM;
2443
2444                        kref_init(&cvp->kref);
2445                }
2446                lock_sock(sk);
2447                tp->rx_opt.cookie_in_always =
2448                        (TCP_COOKIE_IN_ALWAYS & ctd.tcpct_flags);
2449                tp->rx_opt.cookie_out_never = 0; /* false */
2450
2451                if (tp->cookie_values != NULL) {
2452                        if (cvp != NULL) {
2453                                /* Changed values are recorded by a changed
2454                                 * pointer, ensuring the cookie will differ,
2455                                 * without separately hashing each value later.
2456                                 */
2457                                kref_put(&tp->cookie_values->kref,
2458                                         tcp_cookie_values_release);
2459                        } else {
2460                                cvp = tp->cookie_values;
2461                        }
2462                }
2463
2464                if (cvp != NULL) {
2465                        cvp->cookie_desired = ctd.tcpct_cookie_desired;
2466
2467                        if (ctd.tcpct_used > 0) {
2468                                memcpy(cvp->s_data_payload, ctd.tcpct_value,
2469                                       ctd.tcpct_used);
2470                                cvp->s_data_desired = ctd.tcpct_used;
2471                                cvp->s_data_constant = 1; /* true */
2472                        } else {
2473                                /* No constant payload data. */
2474                                cvp->s_data_desired = ctd.tcpct_s_data_desired;
2475                                cvp->s_data_constant = 0; /* false */
2476                        }
2477
2478                        tp->cookie_values = cvp;
2479                }
2480                release_sock(sk);
2481                return err;
2482        }
2483        default:
2484                /* fallthru */
2485                break;
2486        }
2487
2488        if (optlen < sizeof(int))
2489                return -EINVAL;
2490
2491        if (get_user(val, (int __user *)optval))
2492                return -EFAULT;
2493
2494        lock_sock(sk);
2495
2496        switch (optname) {
2497        case TCP_MAXSEG:
2498                /* Values greater than interface MTU won't take effect. However
2499                 * at the point when this call is done we typically don't yet
2500                 * know which interface is going to be used */
2501                if (val < TCP_MIN_MSS || val > MAX_TCP_WINDOW) {
2502                        err = -EINVAL;
2503                        break;
2504                }
2505                tp->rx_opt.user_mss = val;
2506                break;
2507
2508        case TCP_NODELAY:
2509                if (val) {
2510                        /* TCP_NODELAY is weaker than TCP_CORK, so that
2511                         * this option on corked socket is remembered, but
2512                         * it is not activated until cork is cleared.
2513                         *
2514                         * However, when TCP_NODELAY is set we make
2515                         * an explicit push, which overrides even TCP_CORK
2516                         * for currently queued segments.
2517                         */
2518                        tp->nonagle |= TCP_NAGLE_OFF|TCP_NAGLE_PUSH;
2519                        tcp_push_pending_frames(sk);
2520                } else {
2521                        tp->nonagle &= ~TCP_NAGLE_OFF;
2522                }
2523                break;
2524
2525        case TCP_THIN_LINEAR_TIMEOUTS:
2526                if (val < 0 || val > 1)
2527                        err = -EINVAL;
2528                else
2529                        tp->thin_lto = val;
2530                break;
2531
2532        case TCP_THIN_DUPACK:
2533                if (val < 0 || val > 1)
2534                        err = -EINVAL;
2535                else
2536                        tp->thin_dupack = val;
2537                        if (tp->thin_dupack)
2538                                tcp_disable_early_retrans(tp);
2539                break;
2540
2541        case TCP_REPAIR:
2542                if (!tcp_can_repair_sock(sk))
2543                        err = -EPERM;
2544                else if (val == 1) {
2545                        tp->repair = 1;
2546                        sk->sk_reuse = SK_FORCE_REUSE;
2547                        tp->repair_queue = TCP_NO_QUEUE;
2548                } else if (val == 0) {
2549                        tp->repair = 0;
2550                        sk->sk_reuse = SK_NO_REUSE;
2551                        tcp_send_window_probe(sk);
2552                } else
2553                        err = -EINVAL;
2554
2555                break;
2556
2557        case TCP_REPAIR_QUEUE:
2558                if (!tp->repair)
2559                        err = -EPERM;
2560                else if (val < TCP_QUEUES_NR)
2561                        tp->repair_queue = val;
2562                else
2563                        err = -EINVAL;
2564                break;
2565
2566        case TCP_QUEUE_SEQ:
2567                if (sk->sk_state != TCP_CLOSE)
2568                        err = -EPERM;
2569                else if (tp->repair_queue == TCP_SEND_QUEUE)
2570                        tp->write_seq = val;
2571                else if (tp->repair_queue == TCP_RECV_QUEUE)
2572                        tp->rcv_nxt = val;
2573                else
2574                        err = -EINVAL;
2575                break;
2576
2577        case TCP_REPAIR_OPTIONS:
2578                if (!tp->repair)
2579                        err = -EINVAL;
2580                else if (sk->sk_state == TCP_ESTABLISHED)
2581                        err = tcp_repair_options_est(tp,
2582                                        (struct tcp_repair_opt __user *)optval,
2583                                        optlen);
2584                else
2585                        err = -EPERM;
2586                break;
2587
2588        case TCP_CORK:
2589                /* When set indicates to always queue non-full frames.
2590                 * Later the user clears this option and we transmit
2591                 * any pending partial frames in the queue.  This is
2592                 * meant to be used alongside sendfile() to get properly
2593                 * filled frames when the user (for example) must write
2594                 * out headers with a write() call first and then use
2595                 * sendfile to send out the data parts.
2596                 *
2597                 * TCP_CORK can be set together with TCP_NODELAY and it is
2598                 * stronger than TCP_NODELAY.
2599                 */
2600                if (val) {
2601                        tp->nonagle |= TCP_NAGLE_CORK;
2602                } else {
2603                        tp->nonagle &= ~TCP_NAGLE_CORK;
2604                        if (tp->nonagle&TCP_NAGLE_OFF)
2605                                tp->nonagle |= TCP_NAGLE_PUSH;
2606                        tcp_push_pending_frames(sk);
2607                }
2608                break;
2609
2610        case TCP_KEEPIDLE:
2611                if (val < 1 || val > MAX_TCP_KEEPIDLE)
2612                        err = -EINVAL;
2613                else {
2614                        tp->keepalive_time = val * HZ;
2615                        if (sock_flag(sk, SOCK_KEEPOPEN) &&
2616                            !((1 << sk->sk_state) &
2617                              (TCPF_CLOSE | TCPF_LISTEN))) {
2618                                u32 elapsed = keepalive_time_elapsed(tp);
2619                                if (tp->keepalive_time > elapsed)
2620                                        elapsed = tp->keepalive_time - elapsed;
2621                                else
2622                                        elapsed = 0;
2623                                inet_csk_reset_keepalive_timer(sk, elapsed);
2624                        }
2625                }
2626                break;
2627        case TCP_KEEPINTVL:
2628                if (val < 1 || val > MAX_TCP_KEEPINTVL)
2629                        err = -EINVAL;
2630                else
2631                        tp->keepalive_intvl = val * HZ;
2632                break;
2633        case TCP_KEEPCNT:
2634                if (val < 1 || val > MAX_TCP_KEEPCNT)
2635                        err = -EINVAL;
2636                else
2637                        tp->keepalive_probes = val;
2638                break;
2639        case TCP_SYNCNT:
2640                if (val < 1 || val > MAX_TCP_SYNCNT)
2641                        err = -EINVAL;
2642                else
2643                        icsk->icsk_syn_retries = val;
2644                break;
2645
2646        case TCP_LINGER2:
2647                if (val < 0)
2648                        tp->linger2 = -1;
2649                else if (val > sysctl_tcp_fin_timeout / HZ)
2650                        tp->linger2 = 0;
2651                else
2652                        tp->linger2 = val * HZ;
2653                break;
2654
2655        case TCP_DEFER_ACCEPT:
2656                /* Translate value in seconds to number of retransmits */
2657                icsk->icsk_accept_queue.rskq_defer_accept =
2658                        secs_to_retrans(val, TCP_TIMEOUT_INIT / HZ,
2659                                        TCP_RTO_MAX / HZ);
2660                break;
2661
2662        case TCP_WINDOW_CLAMP:
2663                if (!val) {
2664                        if (sk->sk_state != TCP_CLOSE) {
2665                                err = -EINVAL;
2666                                break;
2667                        }
2668                        tp->window_clamp = 0;
2669                } else
2670                        tp->window_clamp = val < SOCK_MIN_RCVBUF / 2 ?
2671                                                SOCK_MIN_RCVBUF / 2 : val;
2672                break;
2673
2674        case TCP_QUICKACK:
2675                if (!val) {
2676                        icsk->icsk_ack.pingpong = 1;
2677                } else {
2678                        icsk->icsk_ack.pingpong = 0;
2679                        if ((1 << sk->sk_state) &
2680                            (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT) &&
2681                            inet_csk_ack_scheduled(sk)) {
2682                                icsk->icsk_ack.pending |= ICSK_ACK_PUSHED;
2683                                tcp_cleanup_rbuf(sk, 1);
2684                                if (!(val & 1))
2685                                        icsk->icsk_ack.pingpong = 1;
2686                        }
2687                }
2688                break;
2689
2690#ifdef CONFIG_TCP_MD5SIG
2691        case TCP_MD5SIG:
2692                /* Read the IP->Key mappings from userspace */
2693                err = tp->af_specific->md5_parse(sk, optval, optlen);
2694                break;
2695#endif
2696        case TCP_USER_TIMEOUT:
2697                /* Cap the max timeout in ms TCP will retry/retrans
2698                 * before giving up and aborting (ETIMEDOUT) a connection.
2699                 */
2700                if (val < 0)
2701                        err = -EINVAL;
2702                else
2703                        icsk->icsk_user_timeout = msecs_to_jiffies(val);
2704                break;
2705
2706        case TCP_FASTOPEN:
2707                if (val >= 0 && ((1 << sk->sk_state) & (TCPF_CLOSE |
2708                    TCPF_LISTEN)))
2709                        err = fastopen_init_queue(sk, val);
2710                else
2711                        err = -EINVAL;
2712                break;
2713        default:
2714                err = -ENOPROTOOPT;
2715                break;
2716        }
2717
2718        release_sock(sk);
2719        return err;
2720}
2721
2722int tcp_setsockopt(struct sock *sk, int level, int optname, char __user *optval,
2723                   unsigned int optlen)
2724{
2725        const struct inet_connection_sock *icsk = inet_csk(sk);
2726
2727        if (level != SOL_TCP)
2728                return icsk->icsk_af_ops->setsockopt(sk, level, optname,
2729                                                     optval, optlen);
2730        return do_tcp_setsockopt(sk, level, optname, optval, optlen);
2731}
2732EXPORT_SYMBOL(tcp_setsockopt);
2733
2734#ifdef CONFIG_COMPAT
2735int compat_tcp_setsockopt(struct sock *sk, int level, int optname,
2736                          char __user *optval, unsigned int optlen)
2737{
2738        if (level != SOL_TCP)
2739                return inet_csk_compat_setsockopt(sk, level, optname,
2740                                                  optval, optlen);
2741        return do_tcp_setsockopt(sk, level, optname, optval, optlen);
2742}
2743EXPORT_SYMBOL(compat_tcp_setsockopt);
2744#endif
2745
2746/* Return information about state of tcp endpoint in API format. */
2747void tcp_get_info(const struct sock *sk, struct tcp_info *info)
2748{
2749        const struct tcp_sock *tp = tcp_sk(sk);
2750        const struct inet_connection_sock *icsk = inet_csk(sk);
2751        u32 now = tcp_time_stamp;
2752
2753        memset(info, 0, sizeof(*info));
2754
2755        info->tcpi_state = sk->sk_state;
2756        info->tcpi_ca_state = icsk->icsk_ca_state;
2757        info->tcpi_retransmits = icsk->icsk_retransmits;
2758        info->tcpi_probes = icsk->icsk_probes_out;
2759        info->tcpi_backoff = icsk->icsk_backoff;
2760
2761        if (tp->rx_opt.tstamp_ok)
2762                info->tcpi_options |= TCPI_OPT_TIMESTAMPS;
2763        if (tcp_is_sack(tp))
2764                info->tcpi_options |= TCPI_OPT_SACK;
2765        if (tp->rx_opt.wscale_ok) {
2766                info->tcpi_options |= TCPI_OPT_WSCALE;
2767                info->tcpi_snd_wscale = tp->rx_opt.snd_wscale;
2768                info->tcpi_rcv_wscale = tp->rx_opt.rcv_wscale;
2769        }
2770
2771        if (tp->ecn_flags & TCP_ECN_OK)
2772                info->tcpi_options |= TCPI_OPT_ECN;
2773        if (tp->ecn_flags & TCP_ECN_SEEN)
2774                info->tcpi_options |= TCPI_OPT_ECN_SEEN;
2775        if (tp->syn_data_acked)
2776                info->tcpi_options |= TCPI_OPT_SYN_DATA;
2777
2778        info->tcpi_rto = jiffies_to_usecs(icsk->icsk_rto);
2779        info->tcpi_ato = jiffies_to_usecs(icsk->icsk_ack.ato);
2780        info->tcpi_snd_mss = tp->mss_cache;
2781        info->tcpi_rcv_mss = icsk->icsk_ack.rcv_mss;
2782
2783        if (sk->sk_state == TCP_LISTEN) {
2784                info->tcpi_unacked = sk->sk_ack_backlog;
2785                info->tcpi_sacked = sk->sk_max_ack_backlog;
2786        } else {
2787                info->tcpi_unacked = tp->packets_out;
2788                info->tcpi_sacked = tp->sacked_out;
2789        }
2790        info->tcpi_lost = tp->lost_out;
2791        info->tcpi_retrans = tp->retrans_out;
2792        info->tcpi_fackets = tp->fackets_out;
2793
2794        info->tcpi_last_data_sent = jiffies_to_msecs(now - tp->lsndtime);
2795        info->tcpi_last_data_recv = jiffies_to_msecs(now - icsk->icsk_ack.lrcvtime);
2796        info->tcpi_last_ack_recv = jiffies_to_msecs(now - tp->rcv_tstamp);
2797
2798        info->tcpi_pmtu = icsk->icsk_pmtu_cookie;
2799        info->tcpi_rcv_ssthresh = tp->rcv_ssthresh;
2800        info->tcpi_rtt = jiffies_to_usecs(tp->srtt)>>3;
2801        info->tcpi_rttvar = jiffies_to_usecs(tp->mdev)>>2;
2802        info->tcpi_snd_ssthresh = tp->snd_ssthresh;
2803        info->tcpi_snd_cwnd = tp->snd_cwnd;
2804        info->tcpi_advmss = tp->advmss;
2805        info->tcpi_reordering = tp->reordering;
2806
2807        info->tcpi_rcv_rtt = jiffies_to_usecs(tp->rcv_rtt_est.rtt)>>3;
2808        info->tcpi_rcv_space = tp->rcvq_space.space;
2809
2810        info->tcpi_total_retrans = tp->total_retrans;
2811}
2812EXPORT_SYMBOL_GPL(tcp_get_info);
2813
2814static int do_tcp_getsockopt(struct sock *sk, int level,
2815                int optname, char __user *optval, int __user *optlen)
2816{
2817        struct inet_connection_sock *icsk = inet_csk(sk);
2818        struct tcp_sock *tp = tcp_sk(sk);
2819        int val, len;
2820
2821        if (get_user(len, optlen))
2822                return -EFAULT;
2823
2824        len = min_t(unsigned int, len, sizeof(int));
2825
2826        if (len < 0)
2827                return -EINVAL;
2828
2829        switch (optname) {
2830        case TCP_MAXSEG:
2831                val = tp->mss_cache;
2832                if (!val && ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN)))
2833                        val = tp->rx_opt.user_mss;
2834                if (tp->repair)
2835                        val = tp->rx_opt.mss_clamp;
2836                break;
2837        case TCP_NODELAY:
2838                val = !!(tp->nonagle&TCP_NAGLE_OFF);
2839                break;
2840        case TCP_CORK:
2841                val = !!(tp->nonagle&TCP_NAGLE_CORK);
2842                break;
2843        case TCP_KEEPIDLE:
2844                val = keepalive_time_when(tp) / HZ;
2845                break;
2846        case TCP_KEEPINTVL:
2847                val = keepalive_intvl_when(tp) / HZ;
2848                break;
2849        case TCP_KEEPCNT:
2850                val = keepalive_probes(tp);
2851                break;
2852        case TCP_SYNCNT:
2853                val = icsk->icsk_syn_retries ? : sysctl_tcp_syn_retries;
2854                break;
2855        case TCP_LINGER2:
2856                val = tp->linger2;
2857                if (val >= 0)
2858                        val = (val ? : sysctl_tcp_fin_timeout) / HZ;
2859                break;
2860        case TCP_DEFER_ACCEPT:
2861                val = retrans_to_secs(icsk->icsk_accept_queue.rskq_defer_accept,
2862                                      TCP_TIMEOUT_INIT / HZ, TCP_RTO_MAX / HZ);
2863                break;
2864        case TCP_WINDOW_CLAMP:
2865                val = tp->window_clamp;
2866                break;
2867        case TCP_INFO: {
2868                struct tcp_info info;
2869
2870                if (get_user(len, optlen))
2871                        return -EFAULT;
2872
2873                tcp_get_info(sk, &info);
2874
2875                len = min_t(unsigned int, len, sizeof(info));
2876                if (put_user(len, optlen))
2877                        return -EFAULT;
2878                if (copy_to_user(optval, &info, len))
2879                        return -EFAULT;
2880                return 0;
2881        }
2882        case TCP_QUICKACK:
2883                val = !icsk->icsk_ack.pingpong;
2884                break;
2885
2886        case TCP_CONGESTION:
2887                if (get_user(len, optlen))
2888                        return -EFAULT;
2889                len = min_t(unsigned int, len, TCP_CA_NAME_MAX);
2890                if (put_user(len, optlen))
2891                        return -EFAULT;
2892                if (copy_to_user(optval, icsk->icsk_ca_ops->name, len))
2893                        return -EFAULT;
2894                return 0;
2895
2896        case TCP_COOKIE_TRANSACTIONS: {
2897                struct tcp_cookie_transactions ctd;
2898                struct tcp_cookie_values *cvp = tp->cookie_values;
2899
2900                if (get_user(len, optlen))
2901                        return -EFAULT;
2902                if (len < sizeof(ctd))
2903                        return -EINVAL;
2904
2905                memset(&ctd, 0, sizeof(ctd));
2906                ctd.tcpct_flags = (tp->rx_opt.cookie_in_always ?
2907                                   TCP_COOKIE_IN_ALWAYS : 0)
2908                                | (tp->rx_opt.cookie_out_never ?
2909                                   TCP_COOKIE_OUT_NEVER : 0);
2910
2911                if (cvp != NULL) {
2912                        ctd.tcpct_flags |= (cvp->s_data_in ?
2913                                            TCP_S_DATA_IN : 0)
2914                                         | (cvp->s_data_out ?
2915                                            TCP_S_DATA_OUT : 0);
2916
2917                        ctd.tcpct_cookie_desired = cvp->cookie_desired;
2918                        ctd.tcpct_s_data_desired = cvp->s_data_desired;
2919
2920                        memcpy(&ctd.tcpct_value[0], &cvp->cookie_pair[0],
2921                               cvp->cookie_pair_size);
2922                        ctd.tcpct_used = cvp->cookie_pair_size;
2923                }
2924
2925                if (put_user(sizeof(ctd), optlen))
2926                        return -EFAULT;
2927                if (copy_to_user(optval, &ctd, sizeof(ctd)))
2928                        return -EFAULT;
2929                return 0;
2930        }
2931        case TCP_THIN_LINEAR_TIMEOUTS:
2932                val = tp->thin_lto;
2933                break;
2934        case TCP_THIN_DUPACK:
2935                val = tp->thin_dupack;
2936                break;
2937
2938        case TCP_REPAIR:
2939                val = tp->repair;
2940                break;
2941
2942        case TCP_REPAIR_QUEUE:
2943                if (tp->repair)
2944                        val = tp->repair_queue;
2945                else
2946                        return -EINVAL;
2947                break;
2948
2949        case TCP_QUEUE_SEQ:
2950                if (tp->repair_queue == TCP_SEND_QUEUE)
2951                        val = tp->write_seq;
2952                else if (tp->repair_queue == TCP_RECV_QUEUE)
2953                        val = tp->rcv_nxt;
2954                else
2955                        return -EINVAL;
2956                break;
2957
2958        case TCP_USER_TIMEOUT:
2959                val = jiffies_to_msecs(icsk->icsk_user_timeout);
2960                break;
2961        default:
2962                return -ENOPROTOOPT;
2963        }
2964
2965        if (put_user(len, optlen))
2966                return -EFAULT;
2967        if (copy_to_user(optval, &val, len))
2968                return -EFAULT;
2969        return 0;
2970}
2971
2972int tcp_getsockopt(struct sock *sk, int level, int optname, char __user *optval,
2973                   int __user *optlen)
2974{
2975        struct inet_connection_sock *icsk = inet_csk(sk);
2976
2977        if (level != SOL_TCP)
2978                return icsk->icsk_af_ops->getsockopt(sk, level, optname,
2979                                                     optval, optlen);
2980        return do_tcp_getsockopt(sk, level, optname, optval, optlen);
2981}
2982EXPORT_SYMBOL(tcp_getsockopt);
2983
2984#ifdef CONFIG_COMPAT
2985int compat_tcp_getsockopt(struct sock *sk, int level, int optname,
2986                          char __user *optval, int __user *optlen)
2987{
2988        if (level != SOL_TCP)
2989                return inet_csk_compat_getsockopt(sk, level, optname,
2990                                                  optval, optlen);
2991        return do_tcp_getsockopt(sk, level, optname, optval, optlen);
2992}
2993EXPORT_SYMBOL(compat_tcp_getsockopt);
2994#endif
2995
2996struct sk_buff *tcp_tso_segment(struct sk_buff *skb,
2997        netdev_features_t features)
2998{
2999        struct sk_buff *segs = ERR_PTR(-EINVAL);
3000        struct tcphdr *th;
3001        unsigned int thlen;
3002        unsigned int seq;
3003        __be32 delta;
3004        unsigned int oldlen;
3005        unsigned int mss;
3006
3007        if (!pskb_may_pull(skb, sizeof(*th)))
3008                goto out;
3009
3010        th = tcp_hdr(skb);
3011        thlen = th->doff * 4;
3012        if (thlen < sizeof(*th))
3013                goto out;
3014
3015        if (!pskb_may_pull(skb, thlen))
3016                goto out;
3017
3018        oldlen = (u16)~skb->len;
3019        __skb_pull(skb, thlen);
3020
3021        mss = skb_shinfo(skb)->gso_size;
3022        if (unlikely(skb->len <= mss))
3023                goto out;
3024
3025        if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) {
3026                /* Packet is from an untrusted source, reset gso_segs. */
3027                int type = skb_shinfo(skb)->gso_type;
3028
3029                if (unlikely(type &
3030                             ~(SKB_GSO_TCPV4 |
3031                               SKB_GSO_DODGY |
3032                               SKB_GSO_TCP_ECN |
3033                               SKB_GSO_TCPV6 |
3034                               0) ||
3035                             !(type & (SKB_GSO_TCPV4 | SKB_GSO_TCPV6))))
3036                        goto out;
3037
3038                skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss);
3039
3040                segs = NULL;
3041                goto out;
3042        }
3043
3044        segs = skb_segment(skb, features);
3045        if (IS_ERR(segs))
3046                goto out;
3047
3048        delta = htonl(oldlen + (thlen + mss));
3049
3050        skb = segs;
3051        th = tcp_hdr(skb);
3052        seq = ntohl(th->seq);
3053
3054        do {
3055                th->fin = th->psh = 0;
3056
3057                th->check = ~csum_fold((__force __wsum)((__force u32)th->check +
3058                                       (__force u32)delta));
3059                if (skb->ip_summed != CHECKSUM_PARTIAL)
3060                        th->check =
3061                             csum_fold(csum_partial(skb_transport_header(skb),
3062                                                    thlen, skb->csum));
3063
3064                seq += mss;
3065                skb = skb->next;
3066                th = tcp_hdr(skb);
3067
3068                th->seq = htonl(seq);
3069                th->cwr = 0;
3070        } while (skb->next);
3071
3072        delta = htonl(oldlen + (skb->tail - skb->transport_header) +
3073                      skb->data_len);
3074        th->check = ~csum_fold((__force __wsum)((__force u32)th->check +
3075                                (__force u32)delta));
3076        if (skb->ip_summed != CHECKSUM_PARTIAL)
3077                th->check = csum_fold(csum_partial(skb_transport_header(skb),
3078                                                   thlen, skb->csum));
3079
3080out:
3081        return segs;
3082}
3083EXPORT_SYMBOL(tcp_tso_segment);
3084
3085struct sk_buff **tcp_gro_receive(struct sk_buff **head, struct sk_buff *skb)
3086{
3087        struct sk_buff **pp = NULL;
3088        struct sk_buff *p;
3089        struct tcphdr *th;
3090        struct tcphdr *th2;
3091        unsigned int len;
3092        unsigned int thlen;
3093        __be32 flags;
3094        unsigned int mss = 1;
3095        unsigned int hlen;
3096        unsigned int off;
3097        int flush = 1;
3098        int i;
3099
3100        off = skb_gro_offset(skb);
3101        hlen = off + sizeof(*th);
3102        th = skb_gro_header_fast(skb, off);
3103        if (skb_gro_header_hard(skb, hlen)) {
3104                th = skb_gro_header_slow(skb, hlen, off);
3105                if (unlikely(!th))
3106                        goto out;
3107        }
3108
3109        thlen = th->doff * 4;
3110        if (thlen < sizeof(*th))
3111                goto out;
3112
3113        hlen = off + thlen;
3114        if (skb_gro_header_hard(skb, hlen)) {
3115                th = skb_gro_header_slow(skb, hlen, off);
3116                if (unlikely(!th))
3117                        goto out;
3118        }
3119
3120        skb_gro_pull(skb, thlen);
3121
3122        len = skb_gro_len(skb);
3123        flags = tcp_flag_word(th);
3124
3125        for (; (p = *head); head = &p->next) {
3126                if (!NAPI_GRO_CB(p)->same_flow)
3127                        continue;
3128
3129                th2 = tcp_hdr(p);
3130
3131                if (*(u32 *)&th->source ^ *(u32 *)&th2->source) {
3132                        NAPI_GRO_CB(p)->same_flow = 0;
3133                        continue;
3134                }
3135
3136                goto found;
3137        }
3138
3139        goto out_check_final;
3140
3141found:
3142        flush = NAPI_GRO_CB(p)->flush;
3143        flush |= (__force int)(flags & TCP_FLAG_CWR);
3144        flush |= (__force int)((flags ^ tcp_flag_word(th2)) &
3145                  ~(TCP_FLAG_CWR | TCP_FLAG_FIN | TCP_FLAG_PSH));
3146        flush |= (__force int)(th->ack_seq ^ th2->ack_seq);
3147        for (i = sizeof(*th); i < thlen; i += 4)
3148                flush |= *(u32 *)((u8 *)th + i) ^
3149                         *(u32 *)((u8 *)th2 + i);
3150
3151        mss = skb_shinfo(p)->gso_size;
3152
3153        flush |= (len - 1) >= mss;
3154        flush |= (ntohl(th2->seq) + skb_gro_len(p)) ^ ntohl(th->seq);
3155
3156        if (flush || skb_gro_receive(head, skb)) {
3157                mss = 1;
3158                goto out_check_final;
3159        }
3160
3161        p = *head;
3162        th2 = tcp_hdr(p);
3163        tcp_flag_word(th2) |= flags & (TCP_FLAG_FIN | TCP_FLAG_PSH);
3164
3165out_check_final:
3166        flush = len < mss;
3167        flush |= (__force int)(flags & (TCP_FLAG_URG | TCP_FLAG_PSH |
3168                                        TCP_FLAG_RST | TCP_FLAG_SYN |
3169                                        TCP_FLAG_FIN));
3170
3171        if (p && (!NAPI_GRO_CB(skb)->same_flow || flush))
3172                pp = head;
3173
3174out:
3175        NAPI_GRO_CB(skb)->flush |= flush;
3176
3177        return pp;
3178}
3179EXPORT_SYMBOL(tcp_gro_receive);
3180
3181int tcp_gro_complete(struct sk_buff *skb)
3182{
3183        struct tcphdr *th = tcp_hdr(skb);
3184
3185        skb->csum_start = skb_transport_header(skb) - skb->head;
3186        skb->csum_offset = offsetof(struct tcphdr, check);
3187        skb->ip_summed = CHECKSUM_PARTIAL;
3188
3189        skb_shinfo(skb)->gso_segs = NAPI_GRO_CB(skb)->count;
3190
3191        if (th->cwr)
3192                skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
3193
3194        return 0;
3195}
3196EXPORT_SYMBOL(tcp_gro_complete);
3197
3198#ifdef CONFIG_TCP_MD5SIG
3199static unsigned long tcp_md5sig_users;
3200static struct tcp_md5sig_pool __percpu *tcp_md5sig_pool;
3201static DEFINE_SPINLOCK(tcp_md5sig_pool_lock);
3202
3203static void __tcp_free_md5sig_pool(struct tcp_md5sig_pool __percpu *pool)
3204{
3205        int cpu;
3206
3207        for_each_possible_cpu(cpu) {
3208                struct tcp_md5sig_pool *p = per_cpu_ptr(pool, cpu);
3209
3210                if (p->md5_desc.tfm)
3211                        crypto_free_hash(p->md5_desc.tfm);
3212        }
3213        free_percpu(pool);
3214}
3215
3216void tcp_free_md5sig_pool(void)
3217{
3218        struct tcp_md5sig_pool __percpu *pool = NULL;
3219
3220        spin_lock_bh(&tcp_md5sig_pool_lock);
3221        if (--tcp_md5sig_users == 0) {
3222                pool = tcp_md5sig_pool;
3223                tcp_md5sig_pool = NULL;
3224        }
3225        spin_unlock_bh(&tcp_md5sig_pool_lock);
3226        if (pool)
3227                __tcp_free_md5sig_pool(pool);
3228}
3229EXPORT_SYMBOL(tcp_free_md5sig_pool);
3230
3231static struct tcp_md5sig_pool __percpu *
3232__tcp_alloc_md5sig_pool(struct sock *sk)
3233{
3234        int cpu;
3235        struct tcp_md5sig_pool __percpu *pool;
3236
3237        pool = alloc_percpu(struct tcp_md5sig_pool);
3238        if (!pool)
3239                return NULL;
3240
3241        for_each_possible_cpu(cpu) {
3242                struct crypto_hash *hash;
3243
3244                hash = crypto_alloc_hash("md5", 0, CRYPTO_ALG_ASYNC);
3245                if (!hash || IS_ERR(hash))
3246                        goto out_free;
3247
3248                per_cpu_ptr(pool, cpu)->md5_desc.tfm = hash;
3249        }
3250        return pool;
3251out_free:
3252        __tcp_free_md5sig_pool(pool);
3253        return NULL;
3254}
3255
3256struct tcp_md5sig_pool __percpu *tcp_alloc_md5sig_pool(struct sock *sk)
3257{
3258        struct tcp_md5sig_pool __percpu *pool;
3259        bool alloc = false;
3260
3261retry:
3262        spin_lock_bh(&tcp_md5sig_pool_lock);
3263        pool = tcp_md5sig_pool;
3264        if (tcp_md5sig_users++ == 0) {
3265                alloc = true;
3266                spin_unlock_bh(&tcp_md5sig_pool_lock);
3267        } else if (!pool) {
3268                tcp_md5sig_users--;
3269                spin_unlock_bh(&tcp_md5sig_pool_lock);
3270                cpu_relax();
3271                goto retry;
3272        } else
3273                spin_unlock_bh(&tcp_md5sig_pool_lock);
3274
3275        if (alloc) {
3276                /* we cannot hold spinlock here because this may sleep. */
3277                struct tcp_md5sig_pool __percpu *p;
3278
3279                p = __tcp_alloc_md5sig_pool(sk);
3280                spin_lock_bh(&tcp_md5sig_pool_lock);
3281                if (!p) {
3282                        tcp_md5sig_users--;
3283                        spin_unlock_bh(&tcp_md5sig_pool_lock);
3284                        return NULL;
3285                }
3286                pool = tcp_md5sig_pool;
3287                if (pool) {
3288                        /* oops, it has already been assigned. */
3289                        spin_unlock_bh(&tcp_md5sig_pool_lock);
3290                        __tcp_free_md5sig_pool(p);
3291                } else {
3292                        tcp_md5sig_pool = pool = p;
3293                        spin_unlock_bh(&tcp_md5sig_pool_lock);
3294                }
3295        }
3296        return pool;
3297}
3298EXPORT_SYMBOL(tcp_alloc_md5sig_pool);
3299
3300
3301/**
3302 *      tcp_get_md5sig_pool - get md5sig_pool for this user
3303 *
3304 *      We use percpu structure, so if we succeed, we exit with preemption
3305 *      and BH disabled, to make sure another thread or softirq handling
3306 *      wont try to get same context.
3307 */
3308struct tcp_md5sig_pool *tcp_get_md5sig_pool(void)
3309{
3310        struct tcp_md5sig_pool __percpu *p;
3311
3312        local_bh_disable();
3313
3314        spin_lock(&tcp_md5sig_pool_lock);
3315        p = tcp_md5sig_pool;
3316        if (p)
3317                tcp_md5sig_users++;
3318        spin_unlock(&tcp_md5sig_pool_lock);
3319
3320        if (p)
3321                return this_cpu_ptr(p);
3322
3323        local_bh_enable();
3324        return NULL;
3325}
3326EXPORT_SYMBOL(tcp_get_md5sig_pool);
3327
3328void tcp_put_md5sig_pool(void)
3329{
3330        local_bh_enable();
3331        tcp_free_md5sig_pool();
3332}
3333EXPORT_SYMBOL(tcp_put_md5sig_pool);
3334
3335int tcp_md5_hash_header(struct tcp_md5sig_pool *hp,
3336                        const struct tcphdr *th)
3337{
3338        struct scatterlist sg;
3339        struct tcphdr hdr;
3340        int err;
3341
3342        /* We are not allowed to change tcphdr, make a local copy */
3343        memcpy(&hdr, th, sizeof(hdr));
3344        hdr.check = 0;
3345
3346        /* options aren't included in the hash */
3347        sg_init_one(&sg, &hdr, sizeof(hdr));
3348        err = crypto_hash_update(&hp->md5_desc, &sg, sizeof(hdr));
3349        return err;
3350}
3351EXPORT_SYMBOL(tcp_md5_hash_header);
3352
3353int tcp_md5_hash_skb_data(struct tcp_md5sig_pool *hp,
3354                          const struct sk_buff *skb, unsigned int header_len)
3355{
3356        struct scatterlist sg;
3357        const struct tcphdr *tp = tcp_hdr(skb);
3358        struct hash_desc *desc = &hp->md5_desc;
3359        unsigned int i;
3360        const unsigned int head_data_len = skb_headlen(skb) > header_len ?
3361                                           skb_headlen(skb) - header_len : 0;
3362        const struct skb_shared_info *shi = skb_shinfo(skb);
3363        struct sk_buff *frag_iter;
3364
3365        sg_init_table(&sg, 1);
3366
3367        sg_set_buf(&sg, ((u8 *) tp) + header_len, head_data_len);
3368        if (crypto_hash_update(desc, &sg, head_data_len))
3369                return 1;
3370
3371        for (i = 0; i < shi->nr_frags; ++i) {
3372                const struct skb_frag_struct *f = &shi->frags[i];
3373                struct page *page = skb_frag_page(f);
3374                sg_set_page(&sg, page, skb_frag_size(f), f->page_offset);
3375                if (crypto_hash_update(desc, &sg, skb_frag_size(f)))
3376                        return 1;
3377        }
3378
3379        skb_walk_frags(skb, frag_iter)
3380                if (tcp_md5_hash_skb_data(hp, frag_iter, 0))
3381                        return 1;
3382
3383        return 0;
3384}
3385EXPORT_SYMBOL(tcp_md5_hash_skb_data);
3386
3387int tcp_md5_hash_key(struct tcp_md5sig_pool *hp, const struct tcp_md5sig_key *key)
3388{
3389        struct scatterlist sg;
3390
3391        sg_init_one(&sg, key->key, key->keylen);
3392        return crypto_hash_update(&hp->md5_desc, &sg, key->keylen);
3393}
3394EXPORT_SYMBOL(tcp_md5_hash_key);
3395
3396#endif
3397
3398/* Each Responder maintains up to two secret values concurrently for
3399 * efficient secret rollover.  Each secret value has 4 states:
3400 *
3401 * Generating.  (tcp_secret_generating != tcp_secret_primary)
3402 *    Generates new Responder-Cookies, but not yet used for primary
3403 *    verification.  This is a short-term state, typically lasting only
3404 *    one round trip time (RTT).
3405 *
3406 * Primary.  (tcp_secret_generating == tcp_secret_primary)
3407 *    Used both for generation and primary verification.
3408 *
3409 * Retiring.  (tcp_secret_retiring != tcp_secret_secondary)
3410 *    Used for verification, until the first failure that can be
3411 *    verified by the newer Generating secret.  At that time, this
3412 *    cookie's state is changed to Secondary, and the Generating
3413 *    cookie's state is changed to Primary.  This is a short-term state,
3414 *    typically lasting only one round trip time (RTT).
3415 *
3416 * Secondary.  (tcp_secret_retiring == tcp_secret_secondary)
3417 *    Used for secondary verification, after primary verification
3418 *    failures.  This state lasts no more than twice the Maximum Segment
3419 *    Lifetime (2MSL).  Then, the secret is discarded.
3420 */
3421struct tcp_cookie_secret {
3422        /* The secret is divided into two parts.  The digest part is the
3423         * equivalent of previously hashing a secret and saving the state,
3424         * and serves as an initialization vector (IV).  The message part
3425         * serves as the trailing secret.
3426         */
3427        u32                             secrets[COOKIE_WORKSPACE_WORDS];
3428        unsigned long                   expires;
3429};
3430
3431#define TCP_SECRET_1MSL (HZ * TCP_PAWS_MSL)
3432#define TCP_SECRET_2MSL (HZ * TCP_PAWS_MSL * 2)
3433#define TCP_SECRET_LIFE (HZ * 600)
3434
3435static struct tcp_cookie_secret tcp_secret_one;
3436static struct tcp_cookie_secret tcp_secret_two;
3437
3438/* Essentially a circular list, without dynamic allocation. */
3439static struct tcp_cookie_secret *tcp_secret_generating;
3440static struct tcp_cookie_secret *tcp_secret_primary;
3441static struct tcp_cookie_secret *tcp_secret_retiring;
3442static struct tcp_cookie_secret *tcp_secret_secondary;
3443
3444static DEFINE_SPINLOCK(tcp_secret_locker);
3445
3446/* Select a pseudo-random word in the cookie workspace.
3447 */
3448static inline u32 tcp_cookie_work(const u32 *ws, const int n)
3449{
3450        return ws[COOKIE_DIGEST_WORDS + ((COOKIE_MESSAGE_WORDS-1) & ws[n])];
3451}
3452
3453/* Fill bakery[COOKIE_WORKSPACE_WORDS] with generator, updating as needed.
3454 * Called in softirq context.
3455 * Returns: 0 for success.
3456 */
3457int tcp_cookie_generator(u32 *bakery)
3458{
3459        unsigned long jiffy = jiffies;
3460
3461        if (unlikely(time_after_eq(jiffy, tcp_secret_generating->expires))) {
3462                spin_lock_bh(&tcp_secret_locker);
3463                if (!time_after_eq(jiffy, tcp_secret_generating->expires)) {
3464                        /* refreshed by another */
3465                        memcpy(bakery,
3466                               &tcp_secret_generating->secrets[0],
3467                               COOKIE_WORKSPACE_WORDS);
3468                } else {
3469                        /* still needs refreshing */
3470                        get_random_bytes(bakery, COOKIE_WORKSPACE_WORDS);
3471
3472                        /* The first time, paranoia assumes that the
3473                         * randomization function isn't as strong.  But,
3474                         * this secret initialization is delayed until
3475                         * the last possible moment (packet arrival).
3476                         * Although that time is observable, it is
3477                         * unpredictably variable.  Mash in the most
3478                         * volatile clock bits available, and expire the
3479                         * secret extra quickly.
3480                         */
3481                        if (unlikely(tcp_secret_primary->expires ==
3482                                     tcp_secret_secondary->expires)) {
3483                                struct timespec tv;
3484
3485                                getnstimeofday(&tv);
3486                                bakery[COOKIE_DIGEST_WORDS+0] ^=
3487                                        (u32)tv.tv_nsec;
3488
3489                                tcp_secret_secondary->expires = jiffy
3490                                        + TCP_SECRET_1MSL
3491                                        + (0x0f & tcp_cookie_work(bakery, 0));
3492                        } else {
3493                                tcp_secret_secondary->expires = jiffy
3494                                        + TCP_SECRET_LIFE
3495                                        + (0xff & tcp_cookie_work(bakery, 1));
3496                                tcp_secret_primary->expires = jiffy
3497                                        + TCP_SECRET_2MSL
3498                                        + (0x1f & tcp_cookie_work(bakery, 2));
3499                        }
3500                        memcpy(&tcp_secret_secondary->secrets[0],
3501                               bakery, COOKIE_WORKSPACE_WORDS);
3502
3503                        rcu_assign_pointer(tcp_secret_generating,
3504                                           tcp_secret_secondary);
3505                        rcu_assign_pointer(tcp_secret_retiring,
3506                                           tcp_secret_primary);
3507                        /*
3508                         * Neither call_rcu() nor synchronize_rcu() needed.
3509                         * Retiring data is not freed.  It is replaced after
3510                         * further (locked) pointer updates, and a quiet time
3511                         * (minimum 1MSL, maximum LIFE - 2MSL).
3512                         */
3513                }
3514                spin_unlock_bh(&tcp_secret_locker);
3515        } else {
3516                rcu_read_lock_bh();
3517                memcpy(bakery,
3518                       &rcu_dereference(tcp_secret_generating)->secrets[0],
3519                       COOKIE_WORKSPACE_WORDS);
3520                rcu_read_unlock_bh();
3521        }
3522        return 0;
3523}
3524EXPORT_SYMBOL(tcp_cookie_generator);
3525
3526void tcp_done(struct sock *sk)
3527{
3528        struct request_sock *req = tcp_sk(sk)->fastopen_rsk;
3529
3530        if (sk->sk_state == TCP_SYN_SENT || sk->sk_state == TCP_SYN_RECV)
3531                TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_ATTEMPTFAILS);
3532
3533        tcp_set_state(sk, TCP_CLOSE);
3534        tcp_clear_xmit_timers(sk);
3535        if (req != NULL)
3536                reqsk_fastopen_remove(sk, req, false);
3537
3538        sk->sk_shutdown = SHUTDOWN_MASK;
3539
3540        if (!sock_flag(sk, SOCK_DEAD))
3541                sk->sk_state_change(sk);
3542        else
3543                inet_csk_destroy_sock(sk);
3544}
3545EXPORT_SYMBOL_GPL(tcp_done);
3546
3547extern struct tcp_congestion_ops tcp_reno;
3548
3549static __initdata unsigned long thash_entries;
3550static int __init set_thash_entries(char *str)
3551{
3552        ssize_t ret;
3553
3554        if (!str)
3555                return 0;
3556
3557        ret = kstrtoul(str, 0, &thash_entries);
3558        if (ret)
3559                return 0;
3560
3561        return 1;
3562}
3563__setup("thash_entries=", set_thash_entries);
3564
3565void tcp_init_mem(struct net *net)
3566{
3567        unsigned long limit = nr_free_buffer_pages() / 8;
3568        limit = max(limit, 128UL);
3569        net->ipv4.sysctl_tcp_mem[0] = limit / 4 * 3;
3570        net->ipv4.sysctl_tcp_mem[1] = limit;
3571        net->ipv4.sysctl_tcp_mem[2] = net->ipv4.sysctl_tcp_mem[0] * 2;
3572}
3573
3574void __init tcp_init(void)
3575{
3576        struct sk_buff *skb = NULL;
3577        unsigned long limit;
3578        int max_rshare, max_wshare, cnt;
3579        unsigned int i;
3580        unsigned long jiffy = jiffies;
3581
3582        BUILD_BUG_ON(sizeof(struct tcp_skb_cb) > sizeof(skb->cb));
3583
3584        percpu_counter_init(&tcp_sockets_allocated, 0);
3585        percpu_counter_init(&tcp_orphan_count, 0);
3586        tcp_hashinfo.bind_bucket_cachep =
3587                kmem_cache_create("tcp_bind_bucket",
3588                                  sizeof(struct inet_bind_bucket), 0,
3589                                  SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
3590
3591        /* Size and allocate the main established and bind bucket
3592         * hash tables.
3593         *
3594         * The methodology is similar to that of the buffer cache.
3595         */
3596        tcp_hashinfo.ehash =
3597                alloc_large_system_hash("TCP established",
3598                                        sizeof(struct inet_ehash_bucket),
3599                                        thash_entries,
3600                                        (totalram_pages >= 128 * 1024) ?
3601                                        13 : 15,
3602                                        0,
3603                                        NULL,
3604                                        &tcp_hashinfo.ehash_mask,
3605                                        0,
3606                                        thash_entries ? 0 : 512 * 1024);
3607        for (i = 0; i <= tcp_hashinfo.ehash_mask; i++) {
3608                INIT_HLIST_NULLS_HEAD(&tcp_hashinfo.ehash[i].chain, i);
3609                INIT_HLIST_NULLS_HEAD(&tcp_hashinfo.ehash[i].twchain, i);
3610        }
3611        if (inet_ehash_locks_alloc(&tcp_hashinfo))
3612                panic("TCP: failed to alloc ehash_locks");
3613        tcp_hashinfo.bhash =
3614                alloc_large_system_hash("TCP bind",
3615                                        sizeof(struct inet_bind_hashbucket),
3616                                        tcp_hashinfo.ehash_mask + 1,
3617                                        (totalram_pages >= 128 * 1024) ?
3618                                        13 : 15,
3619                                        0,
3620                                        &tcp_hashinfo.bhash_size,
3621                                        NULL,
3622                                        0,
3623                                        64 * 1024);
3624        tcp_hashinfo.bhash_size = 1U << tcp_hashinfo.bhash_size;
3625        for (i = 0; i < tcp_hashinfo.bhash_size; i++) {
3626                spin_lock_init(&tcp_hashinfo.bhash[i].lock);
3627                INIT_HLIST_HEAD(&tcp_hashinfo.bhash[i].chain);
3628        }
3629
3630
3631        cnt = tcp_hashinfo.ehash_mask + 1;
3632
3633        tcp_death_row.sysctl_max_tw_buckets = cnt / 2;
3634        sysctl_tcp_max_orphans = cnt / 2;
3635        sysctl_max_syn_backlog = max(128, cnt / 256);
3636
3637        tcp_init_mem(&init_net);
3638        /* Set per-socket limits to no more than 1/128 the pressure threshold */
3639        limit = nr_free_buffer_pages() << (PAGE_SHIFT - 7);
3640        max_wshare = min(4UL*1024*1024, limit);
3641        max_rshare = min(6UL*1024*1024, limit);
3642
3643        sysctl_tcp_wmem[0] = SK_MEM_QUANTUM;
3644        sysctl_tcp_wmem[1] = 16*1024;
3645        sysctl_tcp_wmem[2] = max(64*1024, max_wshare);
3646
3647        sysctl_tcp_rmem[0] = SK_MEM_QUANTUM;
3648        sysctl_tcp_rmem[1] = 87380;
3649        sysctl_tcp_rmem[2] = max(87380, max_rshare);
3650
3651        pr_info("Hash tables configured (established %u bind %u)\n",
3652                tcp_hashinfo.ehash_mask + 1, tcp_hashinfo.bhash_size);
3653
3654        tcp_metrics_init();
3655
3656        tcp_register_congestion_control(&tcp_reno);
3657
3658        memset(&tcp_secret_one.secrets[0], 0, sizeof(tcp_secret_one.secrets));
3659        memset(&tcp_secret_two.secrets[0], 0, sizeof(tcp_secret_two.secrets));
3660        tcp_secret_one.expires = jiffy; /* past due */
3661        tcp_secret_two.expires = jiffy; /* past due */
3662        tcp_secret_generating = &tcp_secret_one;
3663        tcp_secret_primary = &tcp_secret_one;
3664        tcp_secret_retiring = &tcp_secret_two;
3665        tcp_secret_secondary = &tcp_secret_two;
3666        tcp_tasklet_init();
3667}
3668
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