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#include <net/busy_poll.h>
 283
 284int sysctl_tcp_fin_timeout __read_mostly = TCP_FIN_TIMEOUT;
 285
 286int sysctl_tcp_min_tso_segs __read_mostly = 2;
 287
 288int sysctl_tcp_autocorking __read_mostly = 1;
 289
 290struct percpu_counter tcp_orphan_count;
 291EXPORT_SYMBOL_GPL(tcp_orphan_count);
 292
 293long sysctl_tcp_mem[3] __read_mostly;
 294int sysctl_tcp_wmem[3] __read_mostly;
 295int sysctl_tcp_rmem[3] __read_mostly;
 296
 297EXPORT_SYMBOL(sysctl_tcp_mem);
 298EXPORT_SYMBOL(sysctl_tcp_rmem);
 299EXPORT_SYMBOL(sysctl_tcp_wmem);
 300
 301atomic_long_t tcp_memory_allocated;     /* Current allocated memory. */
 302EXPORT_SYMBOL(tcp_memory_allocated);
 303
 304/*
 305 * Current number of TCP sockets.
 306 */
 307struct percpu_counter tcp_sockets_allocated;
 308EXPORT_SYMBOL(tcp_sockets_allocated);
 309
 310/*
 311 * TCP splice context
 312 */
 313struct tcp_splice_state {
 314        struct pipe_inode_info *pipe;
 315        size_t len;
 316        unsigned int flags;
 317};
 318
 319/*
 320 * Pressure flag: try to collapse.
 321 * Technical note: it is used by multiple contexts non atomically.
 322 * All the __sk_mem_schedule() is of this nature: accounting
 323 * is strict, actions are advisory and have some latency.
 324 */
 325int tcp_memory_pressure __read_mostly;
 326EXPORT_SYMBOL(tcp_memory_pressure);
 327
 328void tcp_enter_memory_pressure(struct sock *sk)
 329{
 330        if (!tcp_memory_pressure) {
 331                NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMEMORYPRESSURES);
 332                tcp_memory_pressure = 1;
 333        }
 334}
 335EXPORT_SYMBOL(tcp_enter_memory_pressure);
 336
 337/* Convert seconds to retransmits based on initial and max timeout */
 338static u8 secs_to_retrans(int seconds, int timeout, int rto_max)
 339{
 340        u8 res = 0;
 341
 342        if (seconds > 0) {
 343                int period = timeout;
 344
 345                res = 1;
 346                while (seconds > period && res < 255) {
 347                        res++;
 348                        timeout <<= 1;
 349                        if (timeout > rto_max)
 350                                timeout = rto_max;
 351                        period += timeout;
 352                }
 353        }
 354        return res;
 355}
 356
 357/* Convert retransmits to seconds based on initial and max timeout */
 358static int retrans_to_secs(u8 retrans, int timeout, int rto_max)
 359{
 360        int period = 0;
 361
 362        if (retrans > 0) {
 363                period = timeout;
 364                while (--retrans) {
 365                        timeout <<= 1;
 366                        if (timeout > rto_max)
 367                                timeout = rto_max;
 368                        period += timeout;
 369                }
 370        }
 371        return period;
 372}
 373
 374/* Address-family independent initialization for a tcp_sock.
 375 *
 376 * NOTE: A lot of things set to zero explicitly by call to
 377 *       sk_alloc() so need not be done here.
 378 */
 379void tcp_init_sock(struct sock *sk)
 380{
 381        struct inet_connection_sock *icsk = inet_csk(sk);
 382        struct tcp_sock *tp = tcp_sk(sk);
 383
 384        __skb_queue_head_init(&tp->out_of_order_queue);
 385        tcp_init_xmit_timers(sk);
 386        tcp_prequeue_init(tp);
 387        INIT_LIST_HEAD(&tp->tsq_node);
 388
 389        icsk->icsk_rto = TCP_TIMEOUT_INIT;
 390        tp->mdev = TCP_TIMEOUT_INIT;
 391
 392        /* So many TCP implementations out there (incorrectly) count the
 393         * initial SYN frame in their delayed-ACK and congestion control
 394         * algorithms that we must have the following bandaid to talk
 395         * efficiently to them.  -DaveM
 396         */
 397        tp->snd_cwnd = TCP_INIT_CWND;
 398
 399        /* See draft-stevens-tcpca-spec-01 for discussion of the
 400         * initialization of these values.
 401         */
 402        tp->snd_ssthresh = TCP_INFINITE_SSTHRESH;
 403        tp->snd_cwnd_clamp = ~0;
 404        tp->mss_cache = TCP_MSS_DEFAULT;
 405
 406        tp->reordering = sysctl_tcp_reordering;
 407        tcp_enable_early_retrans(tp);
 408        icsk->icsk_ca_ops = &tcp_init_congestion_ops;
 409
 410        tp->tsoffset = 0;
 411
 412        sk->sk_state = TCP_CLOSE;
 413
 414        sk->sk_write_space = sk_stream_write_space;
 415        sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
 416
 417        icsk->icsk_sync_mss = tcp_sync_mss;
 418
 419        sk->sk_sndbuf = sysctl_tcp_wmem[1];
 420        sk->sk_rcvbuf = sysctl_tcp_rmem[1];
 421
 422        local_bh_disable();
 423        sock_update_memcg(sk);
 424        sk_sockets_allocated_inc(sk);
 425        local_bh_enable();
 426}
 427EXPORT_SYMBOL(tcp_init_sock);
 428
 429/*
 430 *      Wait for a TCP event.
 431 *
 432 *      Note that we don't need to lock the socket, as the upper poll layers
 433 *      take care of normal races (between the test and the event) and we don't
 434 *      go look at any of the socket buffers directly.
 435 */
 436unsigned int tcp_poll(struct file *file, struct socket *sock, poll_table *wait)
 437{
 438        unsigned int mask;
 439        struct sock *sk = sock->sk;
 440        const struct tcp_sock *tp = tcp_sk(sk);
 441
 442        sock_rps_record_flow(sk);
 443
 444        sock_poll_wait(file, sk_sleep(sk), wait);
 445        if (sk->sk_state == TCP_LISTEN)
 446                return inet_csk_listen_poll(sk);
 447
 448        /* Socket is not locked. We are protected from async events
 449         * by poll logic and correct handling of state changes
 450         * made by other threads is impossible in any case.
 451         */
 452
 453        mask = 0;
 454
 455        /*
 456         * POLLHUP is certainly not done right. But poll() doesn't
 457         * have a notion of HUP in just one direction, and for a
 458         * socket the read side is more interesting.
 459         *
 460         * Some poll() documentation says that POLLHUP is incompatible
 461         * with the POLLOUT/POLLWR flags, so somebody should check this
 462         * all. But careful, it tends to be safer to return too many
 463         * bits than too few, and you can easily break real applications
 464         * if you don't tell them that something has hung up!
 465         *
 466         * Check-me.
 467         *
 468         * Check number 1. POLLHUP is _UNMASKABLE_ event (see UNIX98 and
 469         * our fs/select.c). It means that after we received EOF,
 470         * poll always returns immediately, making impossible poll() on write()
 471         * in state CLOSE_WAIT. One solution is evident --- to set POLLHUP
 472         * if and only if shutdown has been made in both directions.
 473         * Actually, it is interesting to look how Solaris and DUX
 474         * solve this dilemma. I would prefer, if POLLHUP were maskable,
 475         * then we could set it on SND_SHUTDOWN. BTW examples given
 476         * in Stevens' books assume exactly this behaviour, it explains
 477         * why POLLHUP is incompatible with POLLOUT.    --ANK
 478         *
 479         * NOTE. Check for TCP_CLOSE is added. The goal is to prevent
 480         * blocking on fresh not-connected or disconnected socket. --ANK
 481         */
 482        if (sk->sk_shutdown == SHUTDOWN_MASK || sk->sk_state == TCP_CLOSE)
 483                mask |= POLLHUP;
 484        if (sk->sk_shutdown & RCV_SHUTDOWN)
 485                mask |= POLLIN | POLLRDNORM | POLLRDHUP;
 486
 487        /* Connected or passive Fast Open socket? */
 488        if (sk->sk_state != TCP_SYN_SENT &&
 489            (sk->sk_state != TCP_SYN_RECV || tp->fastopen_rsk != NULL)) {
 490                int target = sock_rcvlowat(sk, 0, INT_MAX);
 491
 492                if (tp->urg_seq == tp->copied_seq &&
 493                    !sock_flag(sk, SOCK_URGINLINE) &&
 494                    tp->urg_data)
 495                        target++;
 496
 497                /* Potential race condition. If read of tp below will
 498                 * escape above sk->sk_state, we can be illegally awaken
 499                 * in SYN_* states. */
 500                if (tp->rcv_nxt - tp->copied_seq >= target)
 501                        mask |= POLLIN | POLLRDNORM;
 502
 503                if (!(sk->sk_shutdown & SEND_SHUTDOWN)) {
 504                        if (sk_stream_is_writeable(sk)) {
 505                                mask |= POLLOUT | POLLWRNORM;
 506                        } else {  /* send SIGIO later */
 507                                set_bit(SOCK_ASYNC_NOSPACE,
 508                                        &sk->sk_socket->flags);
 509                                set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
 510
 511                                /* Race breaker. If space is freed after
 512                                 * wspace test but before the flags are set,
 513                                 * IO signal will be lost.
 514                                 */
 515                                if (sk_stream_is_writeable(sk))
 516                                        mask |= POLLOUT | POLLWRNORM;
 517                        }
 518                } else
 519                        mask |= POLLOUT | POLLWRNORM;
 520
 521                if (tp->urg_data & TCP_URG_VALID)
 522                        mask |= POLLPRI;
 523        }
 524        /* This barrier is coupled with smp_wmb() in tcp_reset() */
 525        smp_rmb();
 526        if (sk->sk_err)
 527                mask |= POLLERR;
 528
 529        return mask;
 530}
 531EXPORT_SYMBOL(tcp_poll);
 532
 533int tcp_ioctl(struct sock *sk, int cmd, unsigned long arg)
 534{
 535        struct tcp_sock *tp = tcp_sk(sk);
 536        int answ;
 537        bool slow;
 538
 539        switch (cmd) {
 540        case SIOCINQ:
 541                if (sk->sk_state == TCP_LISTEN)
 542                        return -EINVAL;
 543
 544                slow = lock_sock_fast(sk);
 545                if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
 546                        answ = 0;
 547                else if (sock_flag(sk, SOCK_URGINLINE) ||
 548                         !tp->urg_data ||
 549                         before(tp->urg_seq, tp->copied_seq) ||
 550                         !before(tp->urg_seq, tp->rcv_nxt)) {
 551
 552                        answ = tp->rcv_nxt - tp->copied_seq;
 553
 554                        /* Subtract 1, if FIN was received */
 555                        if (answ && sock_flag(sk, SOCK_DONE))
 556                                answ--;
 557                } else
 558                        answ = tp->urg_seq - tp->copied_seq;
 559                unlock_sock_fast(sk, slow);
 560                break;
 561        case SIOCATMARK:
 562                answ = tp->urg_data && tp->urg_seq == tp->copied_seq;
 563                break;
 564        case SIOCOUTQ:
 565                if (sk->sk_state == TCP_LISTEN)
 566                        return -EINVAL;
 567
 568                if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
 569                        answ = 0;
 570                else
 571                        answ = tp->write_seq - tp->snd_una;
 572                break;
 573        case SIOCOUTQNSD:
 574                if (sk->sk_state == TCP_LISTEN)
 575                        return -EINVAL;
 576
 577                if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
 578                        answ = 0;
 579                else
 580                        answ = tp->write_seq - tp->snd_nxt;
 581                break;
 582        default:
 583                return -ENOIOCTLCMD;
 584        }
 585
 586        return put_user(answ, (int __user *)arg);
 587}
 588EXPORT_SYMBOL(tcp_ioctl);
 589
 590static inline void tcp_mark_push(struct tcp_sock *tp, struct sk_buff *skb)
 591{
 592        TCP_SKB_CB(skb)->tcp_flags |= TCPHDR_PSH;
 593        tp->pushed_seq = tp->write_seq;
 594}
 595
 596static inline bool forced_push(const struct tcp_sock *tp)
 597{
 598        return after(tp->write_seq, tp->pushed_seq + (tp->max_window >> 1));
 599}
 600
 601static inline void skb_entail(struct sock *sk, struct sk_buff *skb)
 602{
 603        struct tcp_sock *tp = tcp_sk(sk);
 604        struct tcp_skb_cb *tcb = TCP_SKB_CB(skb);
 605
 606        skb->csum    = 0;
 607        tcb->seq     = tcb->end_seq = tp->write_seq;
 608        tcb->tcp_flags = TCPHDR_ACK;
 609        tcb->sacked  = 0;
 610        skb_header_release(skb);
 611        tcp_add_write_queue_tail(sk, skb);
 612        sk->sk_wmem_queued += skb->truesize;
 613        sk_mem_charge(sk, skb->truesize);
 614        if (tp->nonagle & TCP_NAGLE_PUSH)
 615                tp->nonagle &= ~TCP_NAGLE_PUSH;
 616}
 617
 618static inline void tcp_mark_urg(struct tcp_sock *tp, int flags)
 619{
 620        if (flags & MSG_OOB)
 621                tp->snd_up = tp->write_seq;
 622}
 623
 624/* If a not yet filled skb is pushed, do not send it if
 625 * we have data packets in Qdisc or NIC queues :
 626 * Because TX completion will happen shortly, it gives a chance
 627 * to coalesce future sendmsg() payload into this skb, without
 628 * need for a timer, and with no latency trade off.
 629 * As packets containing data payload have a bigger truesize
 630 * than pure acks (dataless) packets, the last checks prevent
 631 * autocorking if we only have an ACK in Qdisc/NIC queues,
 632 * or if TX completion was delayed after we processed ACK packet.
 633 */
 634static bool tcp_should_autocork(struct sock *sk, struct sk_buff *skb,
 635                                int size_goal)
 636{
 637        return skb->len < size_goal &&
 638               sysctl_tcp_autocorking &&
 639               skb != tcp_write_queue_head(sk) &&
 640               atomic_read(&sk->sk_wmem_alloc) > skb->truesize;
 641}
 642
 643static void tcp_push(struct sock *sk, int flags, int mss_now,
 644                     int nonagle, int size_goal)
 645{
 646        struct tcp_sock *tp = tcp_sk(sk);
 647        struct sk_buff *skb;
 648
 649        if (!tcp_send_head(sk))
 650                return;
 651
 652        skb = tcp_write_queue_tail(sk);
 653        if (!(flags & MSG_MORE) || forced_push(tp))
 654                tcp_mark_push(tp, skb);
 655
 656        tcp_mark_urg(tp, flags);
 657
 658        if (tcp_should_autocork(sk, skb, size_goal)) {
 659
 660                /* avoid atomic op if TSQ_THROTTLED bit is already set */
 661                if (!test_bit(TSQ_THROTTLED, &tp->tsq_flags)) {
 662                        NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPAUTOCORKING);
 663                        set_bit(TSQ_THROTTLED, &tp->tsq_flags);
 664                }
 665                /* It is possible TX completion already happened
 666                 * before we set TSQ_THROTTLED.
 667                 */
 668                if (atomic_read(&sk->sk_wmem_alloc) > skb->truesize)
 669                        return;
 670        }
 671
 672        if (flags & MSG_MORE)
 673                nonagle = TCP_NAGLE_CORK;
 674
 675        __tcp_push_pending_frames(sk, mss_now, nonagle);
 676}
 677
 678static int tcp_splice_data_recv(read_descriptor_t *rd_desc, struct sk_buff *skb,
 679                                unsigned int offset, size_t len)
 680{
 681        struct tcp_splice_state *tss = rd_desc->arg.data;
 682        int ret;
 683
 684        ret = skb_splice_bits(skb, offset, tss->pipe, min(rd_desc->count, len),
 685                              tss->flags);
 686        if (ret > 0)
 687                rd_desc->count -= ret;
 688        return ret;
 689}
 690
 691static int __tcp_splice_read(struct sock *sk, struct tcp_splice_state *tss)
 692{
 693        /* Store TCP splice context information in read_descriptor_t. */
 694        read_descriptor_t rd_desc = {
 695                .arg.data = tss,
 696                .count    = tss->len,
 697        };
 698
 699        return tcp_read_sock(sk, &rd_desc, tcp_splice_data_recv);
 700}
 701
 702/**
 703 *  tcp_splice_read - splice data from TCP socket to a pipe
 704 * @sock:       socket to splice from
 705 * @ppos:       position (not valid)
 706 * @pipe:       pipe to splice to
 707 * @len:        number of bytes to splice
 708 * @flags:      splice modifier flags
 709 *
 710 * Description:
 711 *    Will read pages from given socket and fill them into a pipe.
 712 *
 713 **/
 714ssize_t tcp_splice_read(struct socket *sock, loff_t *ppos,
 715                        struct pipe_inode_info *pipe, size_t len,
 716                        unsigned int flags)
 717{
 718        struct sock *sk = sock->sk;
 719        struct tcp_splice_state tss = {
 720                .pipe = pipe,
 721                .len = len,
 722                .flags = flags,
 723        };
 724        long timeo;
 725        ssize_t spliced;
 726        int ret;
 727
 728        sock_rps_record_flow(sk);
 729        /*
 730         * We can't seek on a socket input
 731         */
 732        if (unlikely(*ppos))
 733                return -ESPIPE;
 734
 735        ret = spliced = 0;
 736
 737        lock_sock(sk);
 738
 739        timeo = sock_rcvtimeo(sk, sock->file->f_flags & O_NONBLOCK);
 740        while (tss.len) {
 741                ret = __tcp_splice_read(sk, &tss);
 742                if (ret < 0)
 743                        break;
 744                else if (!ret) {
 745                        if (spliced)
 746                                break;
 747                        if (sock_flag(sk, SOCK_DONE))
 748                                break;
 749                        if (sk->sk_err) {
 750                                ret = sock_error(sk);
 751                                break;
 752                        }
 753                        if (sk->sk_shutdown & RCV_SHUTDOWN)
 754                                break;
 755                        if (sk->sk_state == TCP_CLOSE) {
 756                                /*
 757                                 * This occurs when user tries to read
 758                                 * from never connected socket.
 759                                 */
 760                                if (!sock_flag(sk, SOCK_DONE))
 761                                        ret = -ENOTCONN;
 762                                break;
 763                        }
 764                        if (!timeo) {
 765                                ret = -EAGAIN;
 766                                break;
 767                        }
 768                        sk_wait_data(sk, &timeo);
 769                        if (signal_pending(current)) {
 770                                ret = sock_intr_errno(timeo);
 771                                break;
 772                        }
 773                        continue;
 774                }
 775                tss.len -= ret;
 776                spliced += ret;
 777
 778                if (!timeo)
 779                        break;
 780                release_sock(sk);
 781                lock_sock(sk);
 782
 783                if (sk->sk_err || sk->sk_state == TCP_CLOSE ||
 784                    (sk->sk_shutdown & RCV_SHUTDOWN) ||
 785                    signal_pending(current))
 786                        break;
 787        }
 788
 789        release_sock(sk);
 790
 791        if (spliced)
 792                return spliced;
 793
 794        return ret;
 795}
 796EXPORT_SYMBOL(tcp_splice_read);
 797
 798struct sk_buff *sk_stream_alloc_skb(struct sock *sk, int size, gfp_t gfp)
 799{
 800        struct sk_buff *skb;
 801
 802        /* The TCP header must be at least 32-bit aligned.  */
 803        size = ALIGN(size, 4);
 804
 805        skb = alloc_skb_fclone(size + sk->sk_prot->max_header, gfp);
 806        if (skb) {
 807                if (sk_wmem_schedule(sk, skb->truesize)) {
 808                        skb_reserve(skb, sk->sk_prot->max_header);
 809                        /*
 810                         * Make sure that we have exactly size bytes
 811                         * available to the caller, no more, no less.
 812                         */
 813                        skb->reserved_tailroom = skb->end - skb->tail - size;
 814                        return skb;
 815                }
 816                __kfree_skb(skb);
 817        } else {
 818                sk->sk_prot->enter_memory_pressure(sk);
 819                sk_stream_moderate_sndbuf(sk);
 820        }
 821        return NULL;
 822}
 823
 824static unsigned int tcp_xmit_size_goal(struct sock *sk, u32 mss_now,
 825                                       int large_allowed)
 826{
 827        struct tcp_sock *tp = tcp_sk(sk);
 828        u32 xmit_size_goal, old_size_goal;
 829
 830        xmit_size_goal = mss_now;
 831
 832        if (large_allowed && sk_can_gso(sk)) {
 833                u32 gso_size, hlen;
 834
 835                /* Maybe we should/could use sk->sk_prot->max_header here ? */
 836                hlen = inet_csk(sk)->icsk_af_ops->net_header_len +
 837                       inet_csk(sk)->icsk_ext_hdr_len +
 838                       tp->tcp_header_len;
 839
 840                /* Goal is to send at least one packet per ms,
 841                 * not one big TSO packet every 100 ms.
 842                 * This preserves ACK clocking and is consistent
 843                 * with tcp_tso_should_defer() heuristic.
 844                 */
 845                gso_size = sk->sk_pacing_rate / (2 * MSEC_PER_SEC);
 846                gso_size = max_t(u32, gso_size,
 847                                 sysctl_tcp_min_tso_segs * mss_now);
 848
 849                xmit_size_goal = min_t(u32, gso_size,
 850                                       sk->sk_gso_max_size - 1 - hlen);
 851
 852                xmit_size_goal = tcp_bound_to_half_wnd(tp, xmit_size_goal);
 853
 854                /* We try hard to avoid divides here */
 855                old_size_goal = tp->xmit_size_goal_segs * mss_now;
 856
 857                if (likely(old_size_goal <= xmit_size_goal &&
 858                           old_size_goal + mss_now > xmit_size_goal)) {
 859                        xmit_size_goal = old_size_goal;
 860                } else {
 861                        tp->xmit_size_goal_segs =
 862                                min_t(u16, xmit_size_goal / mss_now,
 863                                      sk->sk_gso_max_segs);
 864                        xmit_size_goal = tp->xmit_size_goal_segs * mss_now;
 865                }
 866        }
 867
 868        return max(xmit_size_goal, mss_now);
 869}
 870
 871static int tcp_send_mss(struct sock *sk, int *size_goal, int flags)
 872{
 873        int mss_now;
 874
 875        mss_now = tcp_current_mss(sk);
 876        *size_goal = tcp_xmit_size_goal(sk, mss_now, !(flags & MSG_OOB));
 877
 878        return mss_now;
 879}
 880
 881static ssize_t do_tcp_sendpages(struct sock *sk, struct page *page, int offset,
 882                                size_t size, int flags)
 883{
 884        struct tcp_sock *tp = tcp_sk(sk);
 885        int mss_now, size_goal;
 886        int err;
 887        ssize_t copied;
 888        long timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
 889
 890        /* Wait for a connection to finish. One exception is TCP Fast Open
 891         * (passive side) where data is allowed to be sent before a connection
 892         * is fully established.
 893         */
 894        if (((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) &&
 895            !tcp_passive_fastopen(sk)) {
 896                if ((err = sk_stream_wait_connect(sk, &timeo)) != 0)
 897                        goto out_err;
 898        }
 899
 900        clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
 901
 902        mss_now = tcp_send_mss(sk, &size_goal, flags);
 903        copied = 0;
 904
 905        err = -EPIPE;
 906        if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
 907                goto out_err;
 908
 909        while (size > 0) {
 910                struct sk_buff *skb = tcp_write_queue_tail(sk);
 911                int copy, i;
 912                bool can_coalesce;
 913
 914                if (!tcp_send_head(sk) || (copy = size_goal - skb->len) <= 0) {
 915new_segment:
 916                        if (!sk_stream_memory_free(sk))
 917                                goto wait_for_sndbuf;
 918
 919                        skb = sk_stream_alloc_skb(sk, 0, sk->sk_allocation);
 920                        if (!skb)
 921                                goto wait_for_memory;
 922
 923                        skb_entail(sk, skb);
 924                        copy = size_goal;
 925                }
 926
 927                if (copy > size)
 928                        copy = size;
 929
 930                i = skb_shinfo(skb)->nr_frags;
 931                can_coalesce = skb_can_coalesce(skb, i, page, offset);
 932                if (!can_coalesce && i >= MAX_SKB_FRAGS) {
 933                        tcp_mark_push(tp, skb);
 934                        goto new_segment;
 935                }
 936                if (!sk_wmem_schedule(sk, copy))
 937                        goto wait_for_memory;
 938
 939                if (can_coalesce) {
 940                        skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy);
 941                } else {
 942                        get_page(page);
 943                        skb_fill_page_desc(skb, i, page, offset, copy);
 944                }
 945                skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG;
 946
 947                skb->len += copy;
 948                skb->data_len += copy;
 949                skb->truesize += copy;
 950                sk->sk_wmem_queued += copy;
 951                sk_mem_charge(sk, copy);
 952                skb->ip_summed = CHECKSUM_PARTIAL;
 953                tp->write_seq += copy;
 954                TCP_SKB_CB(skb)->end_seq += copy;
 955                skb_shinfo(skb)->gso_segs = 0;
 956
 957                if (!copied)
 958                        TCP_SKB_CB(skb)->tcp_flags &= ~TCPHDR_PSH;
 959
 960                copied += copy;
 961                offset += copy;
 962                if (!(size -= copy))
 963                        goto out;
 964
 965                if (skb->len < size_goal || (flags & MSG_OOB))
 966                        continue;
 967
 968                if (forced_push(tp)) {
 969                        tcp_mark_push(tp, skb);
 970                        __tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH);
 971                } else if (skb == tcp_send_head(sk))
 972                        tcp_push_one(sk, mss_now);
 973                continue;
 974
 975wait_for_sndbuf:
 976                set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
 977wait_for_memory:
 978                tcp_push(sk, flags & ~MSG_MORE, mss_now,
 979                         TCP_NAGLE_PUSH, size_goal);
 980
 981                if ((err = sk_stream_wait_memory(sk, &timeo)) != 0)
 982                        goto do_error;
 983
 984                mss_now = tcp_send_mss(sk, &size_goal, flags);
 985        }
 986
 987out:
 988        if (copied && !(flags & MSG_SENDPAGE_NOTLAST))
 989                tcp_push(sk, flags, mss_now, tp->nonagle, size_goal);
 990        return copied;
 991
 992do_error:
 993        if (copied)
 994                goto out;
 995out_err:
 996        return sk_stream_error(sk, flags, err);
 997}
 998
 999int tcp_sendpage(struct sock *sk, struct page *page, int offset,
1000                 size_t size, int flags)
1001{
1002        ssize_t res;
1003
1004        if (!(sk->sk_route_caps & NETIF_F_SG) ||
1005            !(sk->sk_route_caps & NETIF_F_ALL_CSUM))
1006                return sock_no_sendpage(sk->sk_socket, page, offset, size,
1007                                        flags);
1008
1009        lock_sock(sk);
1010        res = do_tcp_sendpages(sk, page, offset, size, flags);
1011        release_sock(sk);
1012        return res;
1013}
1014EXPORT_SYMBOL(tcp_sendpage);
1015
1016static inline int select_size(const struct sock *sk, bool sg)
1017{
1018        const struct tcp_sock *tp = tcp_sk(sk);
1019        int tmp = tp->mss_cache;
1020
1021        if (sg) {
1022                if (sk_can_gso(sk)) {
1023                        /* Small frames wont use a full page:
1024                         * Payload will immediately follow tcp header.
1025                         */
1026                        tmp = SKB_WITH_OVERHEAD(2048 - MAX_TCP_HEADER);
1027                } else {
1028                        int pgbreak = SKB_MAX_HEAD(MAX_TCP_HEADER);
1029
1030                        if (tmp >= pgbreak &&
1031                            tmp <= pgbreak + (MAX_SKB_FRAGS - 1) * PAGE_SIZE)
1032                                tmp = pgbreak;
1033                }
1034        }
1035
1036        return tmp;
1037}
1038
1039void tcp_free_fastopen_req(struct tcp_sock *tp)
1040{
1041        if (tp->fastopen_req != NULL) {
1042                kfree(tp->fastopen_req);
1043                tp->fastopen_req = NULL;
1044        }
1045}
1046
1047static int tcp_sendmsg_fastopen(struct sock *sk, struct msghdr *msg,
1048                                int *copied, size_t size)
1049{
1050        struct tcp_sock *tp = tcp_sk(sk);
1051        int err, flags;
1052
1053        if (!(sysctl_tcp_fastopen & TFO_CLIENT_ENABLE))
1054                return -EOPNOTSUPP;
1055        if (tp->fastopen_req != NULL)
1056                return -EALREADY; /* Another Fast Open is in progress */
1057
1058        tp->fastopen_req = kzalloc(sizeof(struct tcp_fastopen_request),
1059                                   sk->sk_allocation);
1060        if (unlikely(tp->fastopen_req == NULL))
1061                return -ENOBUFS;
1062        tp->fastopen_req->data = msg;
1063        tp->fastopen_req->size = size;
1064
1065        flags = (msg->msg_flags & MSG_DONTWAIT) ? O_NONBLOCK : 0;
1066        err = __inet_stream_connect(sk->sk_socket, msg->msg_name,
1067                                    msg->msg_namelen, flags);
1068        *copied = tp->fastopen_req->copied;
1069        tcp_free_fastopen_req(tp);
1070        return err;
1071}
1072
1073int tcp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
1074                size_t size)
1075{
1076        struct iovec *iov;
1077        struct tcp_sock *tp = tcp_sk(sk);
1078        struct sk_buff *skb;
1079        int iovlen, flags, err, copied = 0;
1080        int mss_now = 0, size_goal, copied_syn = 0, offset = 0;
1081        bool sg;
1082        long timeo;
1083
1084        lock_sock(sk);
1085
1086        flags = msg->msg_flags;
1087        if (flags & MSG_FASTOPEN) {
1088                err = tcp_sendmsg_fastopen(sk, msg, &copied_syn, size);
1089                if (err == -EINPROGRESS && copied_syn > 0)
1090                        goto out;
1091                else if (err)
1092                        goto out_err;
1093                offset = copied_syn;
1094        }
1095
1096        timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
1097
1098        /* Wait for a connection to finish. One exception is TCP Fast Open
1099         * (passive side) where data is allowed to be sent before a connection
1100         * is fully established.
1101         */
1102        if (((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) &&
1103            !tcp_passive_fastopen(sk)) {
1104                if ((err = sk_stream_wait_connect(sk, &timeo)) != 0)
1105                        goto do_error;
1106        }
1107
1108        if (unlikely(tp->repair)) {
1109                if (tp->repair_queue == TCP_RECV_QUEUE) {
1110                        copied = tcp_send_rcvq(sk, msg, size);
1111                        goto out;
1112                }
1113
1114                err = -EINVAL;
1115                if (tp->repair_queue == TCP_NO_QUEUE)
1116                        goto out_err;
1117
1118                /* 'common' sending to sendq */
1119        }
1120
1121        /* This should be in poll */
1122        clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
1123
1124        mss_now = tcp_send_mss(sk, &size_goal, flags);
1125
1126        /* Ok commence sending. */
1127        iovlen = msg->msg_iovlen;
1128        iov = msg->msg_iov;
1129        copied = 0;
1130
1131        err = -EPIPE;
1132        if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
1133                goto out_err;
1134
1135        sg = !!(sk->sk_route_caps & NETIF_F_SG);
1136
1137        while (--iovlen >= 0) {
1138                size_t seglen = iov->iov_len;
1139                unsigned char __user *from = iov->iov_base;
1140
1141                iov++;
1142                if (unlikely(offset > 0)) {  /* Skip bytes copied in SYN */
1143                        if (offset >= seglen) {
1144                                offset -= seglen;
1145                                continue;
1146                        }
1147                        seglen -= offset;
1148                        from += offset;
1149                        offset = 0;
1150                }
1151
1152                while (seglen > 0) {
1153                        int copy = 0;
1154                        int max = size_goal;
1155
1156                        skb = tcp_write_queue_tail(sk);
1157                        if (tcp_send_head(sk)) {
1158                                if (skb->ip_summed == CHECKSUM_NONE)
1159                                        max = mss_now;
1160                                copy = max - skb->len;
1161                        }
1162
1163                        if (copy <= 0) {
1164new_segment:
1165                                /* Allocate new segment. If the interface is SG,
1166                                 * allocate skb fitting to single page.
1167                                 */
1168                                if (!sk_stream_memory_free(sk))
1169                                        goto wait_for_sndbuf;
1170
1171                                skb = sk_stream_alloc_skb(sk,
1172                                                          select_size(sk, sg),
1173                                                          sk->sk_allocation);
1174                                if (!skb)
1175                                        goto wait_for_memory;
1176
1177                                /*
1178                                 * All packets are restored as if they have
1179                                 * already been sent.
1180                                 */
1181                                if (tp->repair)
1182                                        TCP_SKB_CB(skb)->when = tcp_time_stamp;
1183
1184                                /*
1185                                 * Check whether we can use HW checksum.
1186                                 */
1187                                if (sk->sk_route_caps & NETIF_F_ALL_CSUM)
1188                                        skb->ip_summed = CHECKSUM_PARTIAL;
1189
1190                                skb_entail(sk, skb);
1191                                copy = size_goal;
1192                                max = size_goal;
1193                        }
1194
1195                        /* Try to append data to the end of skb. */
1196                        if (copy > seglen)
1197                                copy = seglen;
1198
1199                        /* Where to copy to? */
1200                        if (skb_availroom(skb) > 0) {
1201                                /* We have some space in skb head. Superb! */
1202                                copy = min_t(int, copy, skb_availroom(skb));
1203                                err = skb_add_data_nocache(sk, skb, from, copy);
1204                                if (err)
1205                                        goto do_fault;
1206                        } else {
1207                                bool merge = true;
1208                                int i = skb_shinfo(skb)->nr_frags;
1209                                struct page_frag *pfrag = sk_page_frag(sk);
1210
1211                                if (!sk_page_frag_refill(sk, pfrag))
1212                                        goto wait_for_memory;
1213
1214                                if (!skb_can_coalesce(skb, i, pfrag->page,
1215                                                      pfrag->offset)) {
1216                                        if (i == MAX_SKB_FRAGS || !sg) {
1217                                                tcp_mark_push(tp, skb);
1218                                                goto new_segment;
1219                                        }
1220                                        merge = false;
1221                                }
1222
1223                                copy = min_t(int, copy, pfrag->size - pfrag->offset);
1224
1225                                if (!sk_wmem_schedule(sk, copy))
1226                                        goto wait_for_memory;
1227
1228                                err = skb_copy_to_page_nocache(sk, from, skb,
1229                                                               pfrag->page,
1230                                                               pfrag->offset,
1231                                                               copy);
1232                                if (err)
1233                                        goto do_error;
1234
1235                                /* Update the skb. */
1236                                if (merge) {
1237                                        skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy);
1238                                } else {
1239                                        skb_fill_page_desc(skb, i, pfrag->page,
1240                                                           pfrag->offset, copy);
1241                                        get_page(pfrag->page);
1242                                }
1243                                pfrag->offset += copy;
1244                        }
1245
1246                        if (!copied)
1247                                TCP_SKB_CB(skb)->tcp_flags &= ~TCPHDR_PSH;
1248
1249                        tp->write_seq += copy;
1250                        TCP_SKB_CB(skb)->end_seq += copy;
1251                        skb_shinfo(skb)->gso_segs = 0;
1252
1253                        from += copy;
1254                        copied += copy;
1255                        if ((seglen -= copy) == 0 && iovlen == 0)
1256                                goto out;
1257
1258                        if (skb->len < max || (flags & MSG_OOB) || unlikely(tp->repair))
1259                                continue;
1260
1261                        if (forced_push(tp)) {
1262                                tcp_mark_push(tp, skb);
1263                                __tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH);
1264                        } else if (skb == tcp_send_head(sk))
1265                                tcp_push_one(sk, mss_now);
1266                        continue;
1267
1268wait_for_sndbuf:
1269                        set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
1270wait_for_memory:
1271                        if (copied)
1272                                tcp_push(sk, flags & ~MSG_MORE, mss_now,
1273                                         TCP_NAGLE_PUSH, size_goal);
1274
1275                        if ((err = sk_stream_wait_memory(sk, &timeo)) != 0)
1276                                goto do_error;
1277
1278                        mss_now = tcp_send_mss(sk, &size_goal, flags);
1279                }
1280        }
1281
1282out:
1283        if (copied)
1284                tcp_push(sk, flags, mss_now, tp->nonagle, size_goal);
1285        release_sock(sk);
1286        return copied + copied_syn;
1287
1288do_fault:
1289        if (!skb->len) {
1290                tcp_unlink_write_queue(skb, sk);
1291                /* It is the one place in all of TCP, except connection
1292                 * reset, where we can be unlinking the send_head.
1293                 */
1294                tcp_check_send_head(sk, skb);
1295                sk_wmem_free_skb(sk, skb);
1296        }
1297
1298do_error:
1299        if (copied + copied_syn)
1300                goto out;
1301out_err:
1302        err = sk_stream_error(sk, flags, err);
1303        release_sock(sk);
1304        return err;
1305}
1306EXPORT_SYMBOL(tcp_sendmsg);
1307
1308/*
1309 *      Handle reading urgent data. BSD has very simple semantics for
1310 *      this, no blocking and very strange errors 8)
1311 */
1312
1313static int tcp_recv_urg(struct sock *sk, struct msghdr *msg, int len, int flags)
1314{
1315        struct tcp_sock *tp = tcp_sk(sk);
1316
1317        /* No URG data to read. */
1318        if (sock_flag(sk, SOCK_URGINLINE) || !tp->urg_data ||
1319            tp->urg_data == TCP_URG_READ)
1320                return -EINVAL; /* Yes this is right ! */
1321
1322        if (sk->sk_state == TCP_CLOSE && !sock_flag(sk, SOCK_DONE))
1323                return -ENOTCONN;
1324
1325        if (tp->urg_data & TCP_URG_VALID) {
1326                int err = 0;
1327                char c = tp->urg_data;
1328
1329                if (!(flags & MSG_PEEK))
1330                        tp->urg_data = TCP_URG_READ;
1331
1332                /* Read urgent data. */
1333                msg->msg_flags |= MSG_OOB;
1334
1335                if (len > 0) {
1336                        if (!(flags & MSG_TRUNC))
1337                                err = memcpy_toiovec(msg->msg_iov, &c, 1);
1338                        len = 1;
1339                } else
1340                        msg->msg_flags |= MSG_TRUNC;
1341
1342                return err ? -EFAULT : len;
1343        }
1344
1345        if (sk->sk_state == TCP_CLOSE || (sk->sk_shutdown & RCV_SHUTDOWN))
1346                return 0;
1347
1348        /* Fixed the recv(..., MSG_OOB) behaviour.  BSD docs and
1349         * the available implementations agree in this case:
1350         * this call should never block, independent of the
1351         * blocking state of the socket.
1352         * Mike <pall@rz.uni-karlsruhe.de>
1353         */
1354        return -EAGAIN;
1355}
1356
1357static int tcp_peek_sndq(struct sock *sk, struct msghdr *msg, int len)
1358{
1359        struct sk_buff *skb;
1360        int copied = 0, err = 0;
1361
1362        /* XXX -- need to support SO_PEEK_OFF */
1363
1364        skb_queue_walk(&sk->sk_write_queue, skb) {
1365                err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, skb->len);
1366                if (err)
1367                        break;
1368
1369                copied += skb->len;
1370        }
1371
1372        return err ?: copied;
1373}
1374
1375/* Clean up the receive buffer for full frames taken by the user,
1376 * then send an ACK if necessary.  COPIED is the number of bytes
1377 * tcp_recvmsg has given to the user so far, it speeds up the
1378 * calculation of whether or not we must ACK for the sake of
1379 * a window update.
1380 */
1381void tcp_cleanup_rbuf(struct sock *sk, int copied)
1382{
1383        struct tcp_sock *tp = tcp_sk(sk);
1384        bool time_to_ack = false;
1385
1386        struct sk_buff *skb = skb_peek(&sk->sk_receive_queue);
1387
1388        WARN(skb && !before(tp->copied_seq, TCP_SKB_CB(skb)->end_seq),
1389             "cleanup rbuf bug: copied %X seq %X rcvnxt %X\n",
1390             tp->copied_seq, TCP_SKB_CB(skb)->end_seq, tp->rcv_nxt);
1391
1392        if (inet_csk_ack_scheduled(sk)) {
1393                const struct inet_connection_sock *icsk = inet_csk(sk);
1394                   /* Delayed ACKs frequently hit locked sockets during bulk
1395                    * receive. */
1396                if (icsk->icsk_ack.blocked ||
1397                    /* Once-per-two-segments ACK was not sent by tcp_input.c */
1398                    tp->rcv_nxt - tp->rcv_wup > icsk->icsk_ack.rcv_mss ||
1399                    /*
1400                     * If this read emptied read buffer, we send ACK, if
1401                     * connection is not bidirectional, user drained
1402                     * receive buffer and there was a small segment
1403                     * in queue.
1404                     */
1405                    (copied > 0 &&
1406                     ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED2) ||
1407                      ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED) &&
1408                       !icsk->icsk_ack.pingpong)) &&
1409                      !atomic_read(&sk->sk_rmem_alloc)))
1410                        time_to_ack = true;
1411        }
1412
1413        /* We send an ACK if we can now advertise a non-zero window
1414         * which has been raised "significantly".
1415         *
1416         * Even if window raised up to infinity, do not send window open ACK
1417         * in states, where we will not receive more. It is useless.
1418         */
1419        if (copied > 0 && !time_to_ack && !(sk->sk_shutdown & RCV_SHUTDOWN)) {
1420                __u32 rcv_window_now = tcp_receive_window(tp);
1421
1422                /* Optimize, __tcp_select_window() is not cheap. */
1423                if (2*rcv_window_now <= tp->window_clamp) {
1424                        __u32 new_window = __tcp_select_window(sk);
1425
1426                        /* Send ACK now, if this read freed lots of space
1427                         * in our buffer. Certainly, new_window is new window.
1428                         * We can advertise it now, if it is not less than current one.
1429                         * "Lots" means "at least twice" here.
1430                         */
1431                        if (new_window && new_window >= 2 * rcv_window_now)
1432                                time_to_ack = true;
1433                }
1434        }
1435        if (time_to_ack)
1436                tcp_send_ack(sk);
1437}
1438
1439static void tcp_prequeue_process(struct sock *sk)
1440{
1441        struct sk_buff *skb;
1442        struct tcp_sock *tp = tcp_sk(sk);
1443
1444        NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPPREQUEUED);
1445
1446        /* RX process wants to run with disabled BHs, though it is not
1447         * necessary */
1448        local_bh_disable();
1449        while ((skb = __skb_dequeue(&tp->ucopy.prequeue)) != NULL)
1450                sk_backlog_rcv(sk, skb);
1451        local_bh_enable();
1452
1453        /* Clear memory counter. */
1454        tp->ucopy.memory = 0;
1455}
1456
1457#ifdef CONFIG_NET_DMA
1458static void tcp_service_net_dma(struct sock *sk, bool wait)
1459{
1460        dma_cookie_t done, used;
1461        dma_cookie_t last_issued;
1462        struct tcp_sock *tp = tcp_sk(sk);
1463
1464        if (!tp->ucopy.dma_chan)
1465                return;
1466
1467        last_issued = tp->ucopy.dma_cookie;
1468        dma_async_issue_pending(tp->ucopy.dma_chan);
1469
1470        do {
1471                if (dma_async_is_tx_complete(tp->ucopy.dma_chan,
1472                                              last_issued, &done,
1473                                              &used) == DMA_COMPLETE) {
1474                        /* Safe to free early-copied skbs now */
1475                        __skb_queue_purge(&sk->sk_async_wait_queue);
1476                        break;
1477                } else {
1478                        struct sk_buff *skb;
1479                        while ((skb = skb_peek(&sk->sk_async_wait_queue)) &&
1480                               (dma_async_is_complete(skb->dma_cookie, done,
1481                                                      used) == DMA_COMPLETE)) {
1482                                __skb_dequeue(&sk->sk_async_wait_queue);
1483                                kfree_skb(skb);
1484                        }
1485                }
1486        } while (wait);
1487}
1488#endif
1489
1490static struct sk_buff *tcp_recv_skb(struct sock *sk, u32 seq, u32 *off)
1491{
1492        struct sk_buff *skb;
1493        u32 offset;
1494
1495        while ((skb = skb_peek(&sk->sk_receive_queue)) != NULL) {
1496                offset = seq - TCP_SKB_CB(skb)->seq;
1497                if (tcp_hdr(skb)->syn)
1498                        offset--;
1499                if (offset < skb->len || tcp_hdr(skb)->fin) {
1500                        *off = offset;
1501                        return skb;
1502                }
1503                /* This looks weird, but this can happen if TCP collapsing
1504                 * splitted a fat GRO packet, while we released socket lock
1505                 * in skb_splice_bits()
1506                 */
1507                sk_eat_skb(sk, skb, false);
1508        }
1509        return NULL;
1510}
1511
1512/*
1513 * This routine provides an alternative to tcp_recvmsg() for routines
1514 * that would like to handle copying from skbuffs directly in 'sendfile'
1515 * fashion.
1516 * Note:
1517 *      - It is assumed that the socket was locked by the caller.
1518 *      - The routine does not block.
1519 *      - At present, there is no support for reading OOB data
1520 *        or for 'peeking' the socket using this routine
1521 *        (although both would be easy to implement).
1522 */
1523int tcp_read_sock(struct sock *sk, read_descriptor_t *desc,
1524                  sk_read_actor_t recv_actor)
1525{
1526        struct sk_buff *skb;
1527        struct tcp_sock *tp = tcp_sk(sk);
1528        u32 seq = tp->copied_seq;
1529        u32 offset;
1530        int copied = 0;
1531
1532        if (sk->sk_state == TCP_LISTEN)
1533                return -ENOTCONN;
1534        while ((skb = tcp_recv_skb(sk, seq, &offset)) != NULL) {
1535                if (offset < skb->len) {
1536                        int used;
1537                        size_t len;
1538
1539                        len = skb->len - offset;
1540                        /* Stop reading if we hit a patch of urgent data */
1541                        if (tp->urg_data) {
1542                                u32 urg_offset = tp->urg_seq - seq;
1543                                if (urg_offset < len)
1544                                        len = urg_offset;
1545                                if (!len)
1546                                        break;
1547                        }
1548                        used = recv_actor(desc, skb, offset, len);
1549                        if (used <= 0) {
1550                                if (!copied)
1551                                        copied = used;
1552                                break;
1553                        } else if (used <= len) {
1554                                seq += used;
1555                                copied += used;
1556                                offset += used;
1557                        }
1558                        /* If recv_actor drops the lock (e.g. TCP splice
1559                         * receive) the skb pointer might be invalid when
1560                         * getting here: tcp_collapse might have deleted it
1561                         * while aggregating skbs from the socket queue.
1562                         */
1563                        skb = tcp_recv_skb(sk, seq - 1, &offset);
1564                        if (!skb)
1565                                break;
1566                        /* TCP coalescing might have appended data to the skb.
1567                         * Try to splice more frags
1568                         */
1569                        if (offset + 1 != skb->len)
1570                                continue;
1571                }
1572                if (tcp_hdr(skb)->fin) {
1573                        sk_eat_skb(sk, skb, false);
1574                        ++seq;
1575                        break;
1576                }
1577                sk_eat_skb(sk, skb, false);
1578                if (!desc->count)
1579                        break;
1580                tp->copied_seq = seq;
1581        }
1582        tp->copied_seq = seq;
1583
1584        tcp_rcv_space_adjust(sk);
1585
1586        /* Clean up data we have read: This will do ACK frames. */
1587        if (copied > 0) {
1588                tcp_recv_skb(sk, seq, &offset);
1589                tcp_cleanup_rbuf(sk, copied);
1590        }
1591        return copied;
1592}
1593EXPORT_SYMBOL(tcp_read_sock);
1594
1595/*
1596 *      This routine copies from a sock struct into the user buffer.
1597 *
1598 *      Technical note: in 2.3 we work on _locked_ socket, so that
1599 *      tricks with *seq access order and skb->users are not required.
1600 *      Probably, code can be easily improved even more.
1601 */
1602
1603int tcp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
1604                size_t len, int nonblock, int flags, int *addr_len)
1605{
1606        struct tcp_sock *tp = tcp_sk(sk);
1607        int copied = 0;
1608        u32 peek_seq;
1609        u32 *seq;
1610        unsigned long used;
1611        int err;
1612        int target;             /* Read at least this many bytes */
1613        long timeo;
1614        struct task_struct *user_recv = NULL;
1615        bool copied_early = false;
1616        struct sk_buff *skb;
1617        u32 urg_hole = 0;
1618
1619        if (sk_can_busy_loop(sk) && skb_queue_empty(&sk->sk_receive_queue) &&
1620            (sk->sk_state == TCP_ESTABLISHED))
1621                sk_busy_loop(sk, nonblock);
1622
1623        lock_sock(sk);
1624
1625        err = -ENOTCONN;
1626        if (sk->sk_state == TCP_LISTEN)
1627                goto out;
1628
1629        timeo = sock_rcvtimeo(sk, nonblock);
1630
1631        /* Urgent data needs to be handled specially. */
1632        if (flags & MSG_OOB)
1633                goto recv_urg;
1634
1635        if (unlikely(tp->repair)) {
1636                err = -EPERM;
1637                if (!(flags & MSG_PEEK))
1638                        goto out;
1639
1640                if (tp->repair_queue == TCP_SEND_QUEUE)
1641                        goto recv_sndq;
1642
1643                err = -EINVAL;
1644                if (tp->repair_queue == TCP_NO_QUEUE)
1645                        goto out;
1646
1647                /* 'common' recv queue MSG_PEEK-ing */
1648        }
1649
1650        seq = &tp->copied_seq;
1651        if (flags & MSG_PEEK) {
1652                peek_seq = tp->copied_seq;
1653                seq = &peek_seq;
1654        }
1655
1656        target = sock_rcvlowat(sk, flags & MSG_WAITALL, len);
1657
1658#ifdef CONFIG_NET_DMA
1659        tp->ucopy.dma_chan = NULL;
1660        preempt_disable();
1661        skb = skb_peek_tail(&sk->sk_receive_queue);
1662        {
1663                int available = 0;
1664
1665                if (skb)
1666                        available = TCP_SKB_CB(skb)->seq + skb->len - (*seq);
1667                if ((available < target) &&
1668                    (len > sysctl_tcp_dma_copybreak) && !(flags & MSG_PEEK) &&
1669                    !sysctl_tcp_low_latency &&
1670                    net_dma_find_channel()) {
1671                        preempt_enable();
1672                        tp->ucopy.pinned_list =
1673                                        dma_pin_iovec_pages(msg->msg_iov, len);
1674                } else {
1675                        preempt_enable();
1676                }
1677        }
1678#endif
1679
1680        do {
1681                u32 offset;
1682
1683                /* Are we at urgent data? Stop if we have read anything or have SIGURG pending. */
1684                if (tp->urg_data && tp->urg_seq == *seq) {
1685                        if (copied)
1686                                break;
1687                        if (signal_pending(current)) {
1688                                copied = timeo ? sock_intr_errno(timeo) : -EAGAIN;
1689                                break;
1690                        }
1691                }
1692
1693                /* Next get a buffer. */
1694
1695                skb_queue_walk(&sk->sk_receive_queue, skb) {
1696                        /* Now that we have two receive queues this
1697                         * shouldn't happen.
1698                         */
1699                        if (WARN(before(*seq, TCP_SKB_CB(skb)->seq),
1700                                 "recvmsg bug: copied %X seq %X rcvnxt %X fl %X\n",
1701                                 *seq, TCP_SKB_CB(skb)->seq, tp->rcv_nxt,
1702                                 flags))
1703                                break;
1704
1705                        offset = *seq - TCP_SKB_CB(skb)->seq;
1706                        if (tcp_hdr(skb)->syn)
1707                                offset--;
1708                        if (offset < skb->len)
1709                                goto found_ok_skb;
1710                        if (tcp_hdr(skb)->fin)
1711                                goto found_fin_ok;
1712                        WARN(!(flags & MSG_PEEK),
1713                             "recvmsg bug 2: copied %X seq %X rcvnxt %X fl %X\n",
1714                             *seq, TCP_SKB_CB(skb)->seq, tp->rcv_nxt, flags);
1715                }
1716
1717                /* Well, if we have backlog, try to process it now yet. */
1718
1719                if (copied >= target && !sk->sk_backlog.tail)
1720                        break;
1721
1722                if (copied) {
1723                        if (sk->sk_err ||
1724                            sk->sk_state == TCP_CLOSE ||
1725                            (sk->sk_shutdown & RCV_SHUTDOWN) ||
1726                            !timeo ||
1727                            signal_pending(current))
1728                                break;
1729                } else {
1730                        if (sock_flag(sk, SOCK_DONE))
1731                                break;
1732
1733                        if (sk->sk_err) {
1734                                copied = sock_error(sk);
1735                                break;
1736                        }
1737
1738                        if (sk->sk_shutdown & RCV_SHUTDOWN)
1739                                break;
1740
1741                        if (sk->sk_state == TCP_CLOSE) {
1742                                if (!sock_flag(sk, SOCK_DONE)) {
1743                                        /* This occurs when user tries to read
1744                                         * from never connected socket.
1745                                         */
1746                                        copied = -ENOTCONN;
1747                                        break;
1748                                }
1749                                break;
1750                        }
1751
1752                        if (!timeo) {
1753                                copied = -EAGAIN;
1754                                break;
1755                        }
1756
1757                        if (signal_pending(current)) {
1758                                copied = sock_intr_errno(timeo);
1759                                break;
1760                        }
1761                }
1762
1763                tcp_cleanup_rbuf(sk, copied);
1764
1765                if (!sysctl_tcp_low_latency && tp->ucopy.task == user_recv) {
1766                        /* Install new reader */
1767                        if (!user_recv && !(flags & (MSG_TRUNC | MSG_PEEK))) {
1768                                user_recv = current;
1769                                tp->ucopy.task = user_recv;
1770                                tp->ucopy.iov = msg->msg_iov;
1771                        }
1772
1773                        tp->ucopy.len = len;
1774
1775                        WARN_ON(tp->copied_seq != tp->rcv_nxt &&
1776                                !(flags & (MSG_PEEK | MSG_TRUNC)));
1777
1778                        /* Ugly... If prequeue is not empty, we have to
1779                         * process it before releasing socket, otherwise
1780                         * order will be broken at second iteration.
1781                         * More elegant solution is required!!!
1782                         *
1783                         * Look: we have the following (pseudo)queues:
1784                         *
1785                         * 1. packets in flight
1786                         * 2. backlog
1787                         * 3. prequeue
1788                         * 4. receive_queue
1789                         *
1790                         * Each queue can be processed only if the next ones
1791                         * are empty. At this point we have empty receive_queue.
1792                         * But prequeue _can_ be not empty after 2nd iteration,
1793                         * when we jumped to start of loop because backlog
1794                         * processing added something to receive_queue.
1795                         * We cannot release_sock(), because backlog contains
1796                         * packets arrived _after_ prequeued ones.
1797                         *
1798                         * Shortly, algorithm is clear --- to process all
1799                         * the queues in order. We could make it more directly,
1800                         * requeueing packets from backlog to prequeue, if
1801                         * is not empty. It is more elegant, but eats cycles,
1802                         * unfortunately.
1803                         */
1804                        if (!skb_queue_empty(&tp->ucopy.prequeue))
1805                                goto do_prequeue;
1806
1807                        /* __ Set realtime policy in scheduler __ */
1808                }
1809
1810#ifdef CONFIG_NET_DMA
1811                if (tp->ucopy.dma_chan) {
1812                        if (tp->rcv_wnd == 0 &&
1813                            !skb_queue_empty(&sk->sk_async_wait_queue)) {
1814                                tcp_service_net_dma(sk, true);
1815                                tcp_cleanup_rbuf(sk, copied);
1816                        } else
1817                                dma_async_issue_pending(tp->ucopy.dma_chan);
1818                }
1819#endif
1820                if (copied >= target) {
1821                        /* Do not sleep, just process backlog. */
1822                        release_sock(sk);
1823                        lock_sock(sk);
1824                } else
1825                        sk_wait_data(sk, &timeo);
1826
1827#ifdef CONFIG_NET_DMA
1828                tcp_service_net_dma(sk, false);  /* Don't block */
1829                tp->ucopy.wakeup = 0;
1830#endif
1831
1832                if (user_recv) {
1833                        int chunk;
1834
1835                        /* __ Restore normal policy in scheduler __ */
1836
1837                        if ((chunk = len - tp->ucopy.len) != 0) {
1838                                NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMBACKLOG, chunk);
1839                                len -= chunk;
1840                                copied += chunk;
1841                        }
1842
1843                        if (tp->rcv_nxt == tp->copied_seq &&
1844                            !skb_queue_empty(&tp->ucopy.prequeue)) {
1845do_prequeue:
1846                                tcp_prequeue_process(sk);
1847
1848                                if ((chunk = len - tp->ucopy.len) != 0) {
1849                                        NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
1850                                        len -= chunk;
1851                                        copied += chunk;
1852                                }
1853                        }
1854                }
1855                if ((flags & MSG_PEEK) &&
1856                    (peek_seq - copied - urg_hole != tp->copied_seq)) {
1857                        net_dbg_ratelimited("TCP(%s:%d): Application bug, race in MSG_PEEK\n",
1858                                            current->comm,
1859                                            task_pid_nr(current));
1860                        peek_seq = tp->copied_seq;
1861                }
1862                continue;
1863
1864        found_ok_skb:
1865                /* Ok so how much can we use? */
1866                used = skb->len - offset;
1867                if (len < used)
1868                        used = len;
1869
1870                /* Do we have urgent data here? */
1871                if (tp->urg_data) {
1872                        u32 urg_offset = tp->urg_seq - *seq;
1873                        if (urg_offset < used) {
1874                                if (!urg_offset) {
1875                                        if (!sock_flag(sk, SOCK_URGINLINE)) {
1876                                                ++*seq;
1877                                                urg_hole++;
1878                                                offset++;
1879                                                used--;
1880                                                if (!used)
1881                                                        goto skip_copy;
1882                                        }
1883                                } else
1884                                        used = urg_offset;
1885                        }
1886                }
1887
1888                if (!(flags & MSG_TRUNC)) {
1889#ifdef CONFIG_NET_DMA
1890                        if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list)
1891                                tp->ucopy.dma_chan = net_dma_find_channel();
1892
1893                        if (tp->ucopy.dma_chan) {
1894                                tp->ucopy.dma_cookie = dma_skb_copy_datagram_iovec(
1895                                        tp->ucopy.dma_chan, skb, offset,
1896                                        msg->msg_iov, used,
1897                                        tp->ucopy.pinned_list);
1898
1899                                if (tp->ucopy.dma_cookie < 0) {
1900
1901                                        pr_alert("%s: dma_cookie < 0\n",
1902                                                 __func__);
1903
1904                                        /* Exception. Bailout! */
1905                                        if (!copied)
1906                                                copied = -EFAULT;
1907                                        break;
1908                                }
1909
1910                                dma_async_issue_pending(tp->ucopy.dma_chan);
1911
1912                                if ((offset + used) == skb->len)
1913                                        copied_early = true;
1914
1915                        } else
1916#endif
1917                        {
1918                                err = skb_copy_datagram_iovec(skb, offset,
1919                                                msg->msg_iov, used);
1920                                if (err) {
1921                                        /* Exception. Bailout! */
1922                                        if (!copied)
1923                                                copied = -EFAULT;
1924                                        break;
1925                                }
1926                        }
1927                }
1928
1929                *seq += used;
1930                copied += used;
1931                len -= used;
1932
1933                tcp_rcv_space_adjust(sk);
1934
1935skip_copy:
1936                if (tp->urg_data && after(tp->copied_seq, tp->urg_seq)) {
1937                        tp->urg_data = 0;
1938                        tcp_fast_path_check(sk);
1939                }
1940                if (used + offset < skb->len)
1941                        continue;
1942
1943                if (tcp_hdr(skb)->fin)
1944                        goto found_fin_ok;
1945                if (!(flags & MSG_PEEK)) {
1946                        sk_eat_skb(sk, skb, copied_early);
1947                        copied_early = false;
1948                }
1949                continue;
1950
1951        found_fin_ok:
1952                /* Process the FIN. */
1953                ++*seq;
1954                if (!(flags & MSG_PEEK)) {
1955                        sk_eat_skb(sk, skb, copied_early);
1956                        copied_early = false;
1957                }
1958                break;
1959        } while (len > 0);
1960
1961        if (user_recv) {
1962                if (!skb_queue_empty(&tp->ucopy.prequeue)) {
1963                        int chunk;
1964
1965                        tp->ucopy.len = copied > 0 ? len : 0;
1966
1967                        tcp_prequeue_process(sk);
1968
1969                        if (copied > 0 && (chunk = len - tp->ucopy.len) != 0) {
1970                                NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
1971                                len -= chunk;
1972                                copied += chunk;
1973                        }
1974                }
1975
1976                tp->ucopy.task = NULL;
1977                tp->ucopy.len = 0;
1978        }
1979
1980#ifdef CONFIG_NET_DMA
1981        tcp_service_net_dma(sk, true);  /* Wait for queue to drain */
1982        tp->ucopy.dma_chan = NULL;
1983
1984        if (tp->ucopy.pinned_list) {
1985                dma_unpin_iovec_pages(tp->ucopy.pinned_list);
1986                tp->ucopy.pinned_list = NULL;
1987        }
1988#endif
1989
1990        /* According to UNIX98, msg_name/msg_namelen are ignored
1991         * on connected socket. I was just happy when found this 8) --ANK
1992         */
1993
1994        /* Clean up data we have read: This will do ACK frames. */
1995        tcp_cleanup_rbuf(sk, copied);
1996
1997        release_sock(sk);
1998        return copied;
1999
2000out:
2001        release_sock(sk);
2002        return err;
2003
2004recv_urg:
2005        err = tcp_recv_urg(sk, msg, len, flags);
2006        goto out;
2007
2008recv_sndq:
2009        err = tcp_peek_sndq(sk, msg, len);
2010        goto out;
2011}
2012EXPORT_SYMBOL(tcp_recvmsg);
2013
2014void tcp_set_state(struct sock *sk, int state)
2015{
2016        int oldstate = sk->sk_state;
2017
2018        switch (state) {
2019        case TCP_ESTABLISHED:
2020                if (oldstate != TCP_ESTABLISHED)
2021                        TCP_INC_STATS(sock_net(sk), TCP_MIB_CURRESTAB);
2022                break;
2023
2024        case TCP_CLOSE:
2025                if (oldstate == TCP_CLOSE_WAIT || oldstate == TCP_ESTABLISHED)
2026                        TCP_INC_STATS(sock_net(sk), TCP_MIB_ESTABRESETS);
2027
2028                sk->sk_prot->unhash(sk);
2029                if (inet_csk(sk)->icsk_bind_hash &&
2030                    !(sk->sk_userlocks & SOCK_BINDPORT_LOCK))
2031                        inet_put_port(sk);
2032                /* fall through */
2033        default:
2034                if (oldstate == TCP_ESTABLISHED)
2035                        TCP_DEC_STATS(sock_net(sk), TCP_MIB_CURRESTAB);
2036        }
2037
2038        /* Change state AFTER socket is unhashed to avoid closed
2039         * socket sitting in hash tables.
2040         */
2041        sk->sk_state = state;
2042
2043#ifdef STATE_TRACE
2044        SOCK_DEBUG(sk, "TCP sk=%p, State %s -> %s\n", sk, statename[oldstate], statename[state]);
2045#endif
2046}
2047EXPORT_SYMBOL_GPL(tcp_set_state);
2048
2049/*
2050 *      State processing on a close. This implements the state shift for
2051 *      sending our FIN frame. Note that we only send a FIN for some
2052 *      states. A shutdown() may have already sent the FIN, or we may be
2053 *      closed.
2054 */
2055
2056static const unsigned char new_state[16] = {
2057  /* current state:        new state:      action:      */
2058  /* (Invalid)          */ TCP_CLOSE,
2059  /* TCP_ESTABLISHED    */ TCP_FIN_WAIT1 | TCP_ACTION_FIN,
2060  /* TCP_SYN_SENT       */ TCP_CLOSE,
2061  /* TCP_SYN_RECV       */ TCP_FIN_WAIT1 | TCP_ACTION_FIN,
2062  /* TCP_FIN_WAIT1      */ TCP_FIN_WAIT1,
2063  /* TCP_FIN_WAIT2      */ TCP_FIN_WAIT2,
2064  /* TCP_TIME_WAIT      */ TCP_CLOSE,
2065  /* TCP_CLOSE          */ TCP_CLOSE,
2066  /* TCP_CLOSE_WAIT     */ TCP_LAST_ACK  | TCP_ACTION_FIN,
2067  /* TCP_LAST_ACK       */ TCP_LAST_ACK,
2068  /* TCP_LISTEN         */ TCP_CLOSE,
2069  /* TCP_CLOSING        */ TCP_CLOSING,
2070};
2071
2072static int tcp_close_state(struct sock *sk)
2073{
2074        int next = (int)new_state[sk->sk_state];
2075        int ns = next & TCP_STATE_MASK;
2076
2077        tcp_set_state(sk, ns);
2078
2079        return next & TCP_ACTION_FIN;
2080}
2081
2082/*
2083 *      Shutdown the sending side of a connection. Much like close except
2084 *      that we don't receive shut down or sock_set_flag(sk, SOCK_DEAD).
2085 */
2086
2087void tcp_shutdown(struct sock *sk, int how)
2088{
2089        /*      We need to grab some memory, and put together a FIN,
2090         *      and then put it into the queue to be sent.
2091         *              Tim MacKenzie(tym@dibbler.cs.monash.edu.au) 4 Dec '92.
2092         */
2093        if (!(how & SEND_SHUTDOWN))
2094                return;
2095
2096        /* If we've already sent a FIN, or it's a closed state, skip this. */
2097        if ((1 << sk->sk_state) &
2098            (TCPF_ESTABLISHED | TCPF_SYN_SENT |
2099             TCPF_SYN_RECV | TCPF_CLOSE_WAIT)) {
2100                /* Clear out any half completed packets.  FIN if needed. */
2101                if (tcp_close_state(sk))
2102                        tcp_send_fin(sk);
2103        }
2104}
2105EXPORT_SYMBOL(tcp_shutdown);
2106
2107bool tcp_check_oom(struct sock *sk, int shift)
2108{
2109        bool too_many_orphans, out_of_socket_memory;
2110
2111        too_many_orphans = tcp_too_many_orphans(sk, shift);
2112        out_of_socket_memory = tcp_out_of_memory(sk);
2113
2114        if (too_many_orphans)
2115                net_info_ratelimited("too many orphaned sockets\n");
2116        if (out_of_socket_memory)
2117                net_info_ratelimited("out of memory -- consider tuning tcp_mem\n");
2118        return too_many_orphans || out_of_socket_memory;
2119}
2120
2121void tcp_close(struct sock *sk, long timeout)
2122{
2123        struct sk_buff *skb;
2124        int data_was_unread = 0;
2125        int state;
2126
2127        lock_sock(sk);
2128        sk->sk_shutdown = SHUTDOWN_MASK;
2129
2130        if (sk->sk_state == TCP_LISTEN) {
2131                tcp_set_state(sk, TCP_CLOSE);
2132
2133                /* Special case. */
2134                inet_csk_listen_stop(sk);
2135
2136                goto adjudge_to_death;
2137        }
2138
2139        /*  We need to flush the recv. buffs.  We do this only on the
2140         *  descriptor close, not protocol-sourced closes, because the
2141         *  reader process may not have drained the data yet!
2142         */
2143        while ((skb = __skb_dequeue(&sk->sk_receive_queue)) != NULL) {
2144                u32 len = TCP_SKB_CB(skb)->end_seq - TCP_SKB_CB(skb)->seq -
2145                          tcp_hdr(skb)->fin;
2146                data_was_unread += len;
2147                __kfree_skb(skb);
2148        }
2149
2150        sk_mem_reclaim(sk);
2151
2152        /* If socket has been already reset (e.g. in tcp_reset()) - kill it. */
2153        if (sk->sk_state == TCP_CLOSE)
2154                goto adjudge_to_death;
2155
2156        /* As outlined in RFC 2525, section 2.17, we send a RST here because
2157         * data was lost. To witness the awful effects of the old behavior of
2158         * always doing a FIN, run an older 2.1.x kernel or 2.0.x, start a bulk
2159         * GET in an FTP client, suspend the process, wait for the client to
2160         * advertise a zero window, then kill -9 the FTP client, wheee...
2161         * Note: timeout is always zero in such a case.
2162         */
2163        if (unlikely(tcp_sk(sk)->repair)) {
2164                sk->sk_prot->disconnect(sk, 0);
2165        } else if (data_was_unread) {
2166                /* Unread data was tossed, zap the connection. */
2167                NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPABORTONCLOSE);
2168                tcp_set_state(sk, TCP_CLOSE);
2169                tcp_send_active_reset(sk, sk->sk_allocation);
2170        } else if (sock_flag(sk, SOCK_LINGER) && !sk->sk_lingertime) {
2171                /* Check zero linger _after_ checking for unread data. */
2172                sk->sk_prot->disconnect(sk, 0);
2173                NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPABORTONDATA);
2174        } else if (tcp_close_state(sk)) {
2175                /* We FIN if the application ate all the data before
2176                 * zapping the connection.
2177                 */
2178
2179                /* RED-PEN. Formally speaking, we have broken TCP state
2180                 * machine. State transitions:
2181                 *
2182                 * TCP_ESTABLISHED -> TCP_FIN_WAIT1
2183                 * TCP_SYN_RECV -> TCP_FIN_WAIT1 (forget it, it's impossible)
2184                 * TCP_CLOSE_WAIT -> TCP_LAST_ACK
2185                 *
2186                 * are legal only when FIN has been sent (i.e. in window),
2187                 * rather than queued out of window. Purists blame.
2188                 *
2189                 * F.e. "RFC state" is ESTABLISHED,
2190                 * if Linux state is FIN-WAIT-1, but FIN is still not sent.
2191                 *
2192                 * The visible declinations are that sometimes
2193                 * we enter time-wait state, when it is not required really
2194                 * (harmless), do not send active resets, when they are
2195                 * required by specs (TCP_ESTABLISHED, TCP_CLOSE_WAIT, when
2196                 * they look as CLOSING or LAST_ACK for Linux)
2197                 * Probably, I missed some more holelets.
2198                 *                                              --ANK
2199                 * XXX (TFO) - To start off we don't support SYN+ACK+FIN
2200                 * in a single packet! (May consider it later but will
2201                 * probably need API support or TCP_CORK SYN-ACK until
2202                 * data is written and socket is closed.)
2203                 */
2204                tcp_send_fin(sk);
2205        }
2206
2207        sk_stream_wait_close(sk, timeout);
2208
2209adjudge_to_death:
2210        state = sk->sk_state;
2211        sock_hold(sk);
2212        sock_orphan(sk);
2213
2214        /* It is the last release_sock in its life. It will remove backlog. */
2215        release_sock(sk);
2216
2217
2218        /* Now socket is owned by kernel and we acquire BH lock
2219           to finish close. No need to check for user refs.
2220         */
2221        local_bh_disable();
2222        bh_lock_sock(sk);
2223        WARN_ON(sock_owned_by_user(sk));
2224
2225        percpu_counter_inc(sk->sk_prot->orphan_count);
2226
2227        /* Have we already been destroyed by a softirq or backlog? */
2228        if (state != TCP_CLOSE && sk->sk_state == TCP_CLOSE)
2229                goto out;
2230
2231        /*      This is a (useful) BSD violating of the RFC. There is a
2232         *      problem with TCP as specified in that the other end could
2233         *      keep a socket open forever with no application left this end.
2234         *      We use a 1 minute timeout (about the same as BSD) then kill
2235         *      our end. If they send after that then tough - BUT: long enough
2236         *      that we won't make the old 4*rto = almost no time - whoops
2237         *      reset mistake.
2238         *
2239         *      Nope, it was not mistake. It is really desired behaviour
2240         *      f.e. on http servers, when such sockets are useless, but
2241         *      consume significant resources. Let's do it with special
2242         *      linger2 option.                                 --ANK
2243         */
2244
2245        if (sk->sk_state == TCP_FIN_WAIT2) {
2246                struct tcp_sock *tp = tcp_sk(sk);
2247                if (tp->linger2 < 0) {
2248                        tcp_set_state(sk, TCP_CLOSE);
2249                        tcp_send_active_reset(sk, GFP_ATOMIC);
2250                        NET_INC_STATS_BH(sock_net(sk),
2251                                        LINUX_MIB_TCPABORTONLINGER);
2252                } else {
2253                        const int tmo = tcp_fin_time(sk);
2254
2255                        if (tmo > TCP_TIMEWAIT_LEN) {
2256                                inet_csk_reset_keepalive_timer(sk,
2257                                                tmo - TCP_TIMEWAIT_LEN);
2258                        } else {
2259                                tcp_time_wait(sk, TCP_FIN_WAIT2, tmo);
2260                                goto out;
2261                        }
2262                }
2263        }
2264        if (sk->sk_state != TCP_CLOSE) {
2265                sk_mem_reclaim(sk);
2266                if (tcp_check_oom(sk, 0)) {
2267                        tcp_set_state(sk, TCP_CLOSE);
2268                        tcp_send_active_reset(sk, GFP_ATOMIC);
2269                        NET_INC_STATS_BH(sock_net(sk),
2270                                        LINUX_MIB_TCPABORTONMEMORY);
2271                }
2272        }
2273
2274        if (sk->sk_state == TCP_CLOSE) {
2275                struct request_sock *req = tcp_sk(sk)->fastopen_rsk;
2276                /* We could get here with a non-NULL req if the socket is
2277                 * aborted (e.g., closed with unread data) before 3WHS
2278                 * finishes.
2279                 */
2280                if (req != NULL)
2281                        reqsk_fastopen_remove(sk, req, false);
2282                inet_csk_destroy_sock(sk);
2283        }
2284        /* Otherwise, socket is reprieved until protocol close. */
2285
2286out:
2287        bh_unlock_sock(sk);
2288        local_bh_enable();
2289        sock_put(sk);
2290}
2291EXPORT_SYMBOL(tcp_close);
2292
2293/* These states need RST on ABORT according to RFC793 */
2294
2295static inline bool tcp_need_reset(int state)
2296{
2297        return (1 << state) &
2298               (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT | TCPF_FIN_WAIT1 |
2299                TCPF_FIN_WAIT2 | TCPF_SYN_RECV);
2300}
2301
2302int tcp_disconnect(struct sock *sk, int flags)
2303{
2304        struct inet_sock *inet = inet_sk(sk);
2305        struct inet_connection_sock *icsk = inet_csk(sk);
2306        struct tcp_sock *tp = tcp_sk(sk);
2307        int err = 0;
2308        int old_state = sk->sk_state;
2309
2310        if (old_state != TCP_CLOSE)
2311                tcp_set_state(sk, TCP_CLOSE);
2312
2313        /* ABORT function of RFC793 */
2314        if (old_state == TCP_LISTEN) {
2315                inet_csk_listen_stop(sk);
2316        } else if (unlikely(tp->repair)) {
2317                sk->sk_err = ECONNABORTED;
2318        } else if (tcp_need_reset(old_state) ||
2319                   (tp->snd_nxt != tp->write_seq &&
2320                    (1 << old_state) & (TCPF_CLOSING | TCPF_LAST_ACK))) {
2321                /* The last check adjusts for discrepancy of Linux wrt. RFC
2322                 * states
2323                 */
2324                tcp_send_active_reset(sk, gfp_any());
2325                sk->sk_err = ECONNRESET;
2326        } else if (old_state == TCP_SYN_SENT)
2327                sk->sk_err = ECONNRESET;
2328
2329        tcp_clear_xmit_timers(sk);
2330        __skb_queue_purge(&sk->sk_receive_queue);
2331        tcp_write_queue_purge(sk);
2332        __skb_queue_purge(&tp->out_of_order_queue);
2333#ifdef CONFIG_NET_DMA
2334        __skb_queue_purge(&sk->sk_async_wait_queue);
2335#endif
2336
2337        inet->inet_dport = 0;
2338
2339        if (!(sk->sk_userlocks & SOCK_BINDADDR_LOCK))
2340                inet_reset_saddr(sk);
2341
2342        sk->sk_shutdown = 0;
2343        sock_reset_flag(sk, SOCK_DONE);
2344        tp->srtt = 0;
2345        if ((tp->write_seq += tp->max_window + 2) == 0)
2346                tp->write_seq = 1;
2347        icsk->icsk_backoff = 0;
2348        tp->snd_cwnd = 2;
2349        icsk->icsk_probes_out = 0;
2350        tp->packets_out = 0;
2351        tp->snd_ssthresh = TCP_INFINITE_SSTHRESH;
2352        tp->snd_cwnd_cnt = 0;
2353        tp->window_clamp = 0;
2354        tcp_set_ca_state(sk, TCP_CA_Open);
2355        tcp_clear_retrans(tp);
2356        inet_csk_delack_init(sk);
2357        tcp_init_send_head(sk);
2358        memset(&tp->rx_opt, 0, sizeof(tp->rx_opt));
2359        __sk_dst_reset(sk);
2360
2361        WARN_ON(inet->inet_num && !icsk->icsk_bind_hash);
2362
2363        sk->sk_error_report(sk);
2364        return err;
2365}
2366EXPORT_SYMBOL(tcp_disconnect);
2367
2368void tcp_sock_destruct(struct sock *sk)
2369{
2370        inet_sock_destruct(sk);
2371
2372        kfree(inet_csk(sk)->icsk_accept_queue.fastopenq);
2373}
2374
2375static inline bool tcp_can_repair_sock(const struct sock *sk)
2376{
2377        return ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN) &&
2378                ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_ESTABLISHED));
2379}
2380
2381static int tcp_repair_options_est(struct tcp_sock *tp,
2382                struct tcp_repair_opt __user *optbuf, unsigned int len)
2383{
2384        struct tcp_repair_opt opt;
2385
2386        while (len >= sizeof(opt)) {
2387                if (copy_from_user(&opt, optbuf, sizeof(opt)))
2388                        return -EFAULT;
2389
2390                optbuf++;
2391                len -= sizeof(opt);
2392
2393                switch (opt.opt_code) {
2394                case TCPOPT_MSS:
2395                        tp->rx_opt.mss_clamp = opt.opt_val;
2396                        break;
2397                case TCPOPT_WINDOW:
2398                        {
2399                                u16 snd_wscale = opt.opt_val & 0xFFFF;
2400                                u16 rcv_wscale = opt.opt_val >> 16;
2401
2402                                if (snd_wscale > 14 || rcv_wscale > 14)
2403                                        return -EFBIG;
2404
2405                                tp->rx_opt.snd_wscale = snd_wscale;
2406                                tp->rx_opt.rcv_wscale = rcv_wscale;
2407                                tp->rx_opt.wscale_ok = 1;
2408                        }
2409                        break;
2410                case TCPOPT_SACK_PERM:
2411                        if (opt.opt_val != 0)
2412                                return -EINVAL;
2413
2414                        tp->rx_opt.sack_ok |= TCP_SACK_SEEN;
2415                        if (sysctl_tcp_fack)
2416                                tcp_enable_fack(tp);
2417                        break;
2418                case TCPOPT_TIMESTAMP:
2419                        if (opt.opt_val != 0)
2420                                return -EINVAL;
2421
2422                        tp->rx_opt.tstamp_ok = 1;
2423                        break;
2424                }
2425        }
2426
2427        return 0;
2428}
2429
2430/*
2431 *      Socket option code for TCP.
2432 */
2433static int do_tcp_setsockopt(struct sock *sk, int level,
2434                int optname, char __user *optval, unsigned int optlen)
2435{
2436        struct tcp_sock *tp = tcp_sk(sk);
2437        struct inet_connection_sock *icsk = inet_csk(sk);
2438        int val;
2439        int err = 0;
2440
2441        /* These are data/string values, all the others are ints */
2442        switch (optname) {
2443        case TCP_CONGESTION: {
2444                char name[TCP_CA_NAME_MAX];
2445
2446                if (optlen < 1)
2447                        return -EINVAL;
2448
2449                val = strncpy_from_user(name, optval,
2450                                        min_t(long, TCP_CA_NAME_MAX-1, optlen));
2451                if (val < 0)
2452                        return -EFAULT;
2453                name[val] = 0;
2454
2455                lock_sock(sk);
2456                err = tcp_set_congestion_control(sk, name);
2457                release_sock(sk);
2458                return err;
2459        }
2460        default:
2461                /* fallthru */
2462                break;
2463        }
2464
2465        if (optlen < sizeof(int))
2466                return -EINVAL;
2467
2468        if (get_user(val, (int __user *)optval))
2469                return -EFAULT;
2470
2471        lock_sock(sk);
2472
2473        switch (optname) {
2474        case TCP_MAXSEG:
2475                /* Values greater than interface MTU won't take effect. However
2476                 * at the point when this call is done we typically don't yet
2477                 * know which interface is going to be used */
2478                if (val < TCP_MIN_MSS || val > MAX_TCP_WINDOW) {
2479                        err = -EINVAL;
2480                        break;
2481                }
2482                tp->rx_opt.user_mss = val;
2483                break;
2484
2485        case TCP_NODELAY:
2486                if (val) {
2487                        /* TCP_NODELAY is weaker than TCP_CORK, so that
2488                         * this option on corked socket is remembered, but
2489                         * it is not activated until cork is cleared.
2490                         *
2491                         * However, when TCP_NODELAY is set we make
2492                         * an explicit push, which overrides even TCP_CORK
2493                         * for currently queued segments.
2494                         */
2495                        tp->nonagle |= TCP_NAGLE_OFF|TCP_NAGLE_PUSH;
2496                        tcp_push_pending_frames(sk);
2497                } else {
2498                        tp->nonagle &= ~TCP_NAGLE_OFF;
2499                }
2500                break;
2501
2502        case TCP_THIN_LINEAR_TIMEOUTS:
2503                if (val < 0 || val > 1)
2504                        err = -EINVAL;
2505                else
2506                        tp->thin_lto = val;
2507                break;
2508
2509        case TCP_THIN_DUPACK:
2510                if (val < 0 || val > 1)
2511                        err = -EINVAL;
2512                else {
2513                        tp->thin_dupack = val;
2514                        if (tp->thin_dupack)
2515                                tcp_disable_early_retrans(tp);
2516                }
2517                break;
2518
2519        case TCP_REPAIR:
2520                if (!tcp_can_repair_sock(sk))
2521                        err = -EPERM;
2522                else if (val == 1) {
2523                        tp->repair = 1;
2524                        sk->sk_reuse = SK_FORCE_REUSE;
2525                        tp->repair_queue = TCP_NO_QUEUE;
2526                } else if (val == 0) {
2527                        tp->repair = 0;
2528                        sk->sk_reuse = SK_NO_REUSE;
2529                        tcp_send_window_probe(sk);
2530                } else
2531                        err = -EINVAL;
2532
2533                break;
2534
2535        case TCP_REPAIR_QUEUE:
2536                if (!tp->repair)
2537                        err = -EPERM;
2538                else if (val < TCP_QUEUES_NR)
2539                        tp->repair_queue = val;
2540                else
2541                        err = -EINVAL;
2542                break;
2543
2544        case TCP_QUEUE_SEQ:
2545                if (sk->sk_state != TCP_CLOSE)
2546                        err = -EPERM;
2547                else if (tp->repair_queue == TCP_SEND_QUEUE)
2548                        tp->write_seq = val;
2549                else if (tp->repair_queue == TCP_RECV_QUEUE)
2550                        tp->rcv_nxt = val;
2551                else
2552                        err = -EINVAL;
2553                break;
2554
2555        case TCP_REPAIR_OPTIONS:
2556                if (!tp->repair)
2557                        err = -EINVAL;
2558                else if (sk->sk_state == TCP_ESTABLISHED)
2559                        err = tcp_repair_options_est(tp,
2560                                        (struct tcp_repair_opt __user *)optval,
2561                                        optlen);
2562                else
2563                        err = -EPERM;
2564                break;
2565
2566        case TCP_CORK:
2567                /* When set indicates to always queue non-full frames.
2568                 * Later the user clears this option and we transmit
2569                 * any pending partial frames in the queue.  This is
2570                 * meant to be used alongside sendfile() to get properly
2571                 * filled frames when the user (for example) must write
2572                 * out headers with a write() call first and then use
2573                 * sendfile to send out the data parts.
2574                 *
2575                 * TCP_CORK can be set together with TCP_NODELAY and it is
2576                 * stronger than TCP_NODELAY.
2577                 */
2578                if (val) {
2579                        tp->nonagle |= TCP_NAGLE_CORK;
2580                } else {
2581                        tp->nonagle &= ~TCP_NAGLE_CORK;
2582                        if (tp->nonagle&TCP_NAGLE_OFF)
2583                                tp->nonagle |= TCP_NAGLE_PUSH;
2584                        tcp_push_pending_frames(sk);
2585                }
2586                break;
2587
2588        case TCP_KEEPIDLE:
2589                if (val < 1 || val > MAX_TCP_KEEPIDLE)
2590                        err = -EINVAL;
2591                else {
2592                        tp->keepalive_time = val * HZ;
2593                        if (sock_flag(sk, SOCK_KEEPOPEN) &&
2594                            !((1 << sk->sk_state) &
2595                              (TCPF_CLOSE | TCPF_LISTEN))) {
2596                                u32 elapsed = keepalive_time_elapsed(tp);
2597                                if (tp->keepalive_time > elapsed)
2598                                        elapsed = tp->keepalive_time - elapsed;
2599                                else
2600                                        elapsed = 0;
2601                                inet_csk_reset_keepalive_timer(sk, elapsed);
2602                        }
2603                }
2604                break;
2605        case TCP_KEEPINTVL:
2606                if (val < 1 || val > MAX_TCP_KEEPINTVL)
2607                        err = -EINVAL;
2608                else
2609                        tp->keepalive_intvl = val * HZ;
2610                break;
2611        case TCP_KEEPCNT:
2612                if (val < 1 || val > MAX_TCP_KEEPCNT)
2613                        err = -EINVAL;
2614                else
2615                        tp->keepalive_probes = val;
2616                break;
2617        case TCP_SYNCNT:
2618                if (val < 1 || val > MAX_TCP_SYNCNT)
2619                        err = -EINVAL;
2620                else
2621                        icsk->icsk_syn_retries = val;
2622                break;
2623
2624        case TCP_LINGER2:
2625                if (val < 0)
2626                        tp->linger2 = -1;
2627                else if (val > sysctl_tcp_fin_timeout / HZ)
2628                        tp->linger2 = 0;
2629                else
2630                        tp->linger2 = val * HZ;
2631                break;
2632
2633        case TCP_DEFER_ACCEPT:
2634                /* Translate value in seconds to number of retransmits */
2635                icsk->icsk_accept_queue.rskq_defer_accept =
2636                        secs_to_retrans(val, TCP_TIMEOUT_INIT / HZ,
2637                                        TCP_RTO_MAX / HZ);
2638                break;
2639
2640        case TCP_WINDOW_CLAMP:
2641                if (!val) {
2642                        if (sk->sk_state != TCP_CLOSE) {
2643                                err = -EINVAL;
2644                                break;
2645                        }
2646                        tp->window_clamp = 0;
2647                } else
2648                        tp->window_clamp = val < SOCK_MIN_RCVBUF / 2 ?
2649                                                SOCK_MIN_RCVBUF / 2 : val;
2650                break;
2651
2652        case TCP_QUICKACK:
2653                if (!val) {
2654                        icsk->icsk_ack.pingpong = 1;
2655                } else {
2656                        icsk->icsk_ack.pingpong = 0;
2657                        if ((1 << sk->sk_state) &
2658                            (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT) &&
2659                            inet_csk_ack_scheduled(sk)) {
2660                                icsk->icsk_ack.pending |= ICSK_ACK_PUSHED;
2661                                tcp_cleanup_rbuf(sk, 1);
2662                                if (!(val & 1))
2663                                        icsk->icsk_ack.pingpong = 1;
2664                        }
2665                }
2666                break;
2667
2668#ifdef CONFIG_TCP_MD5SIG
2669        case TCP_MD5SIG:
2670                /* Read the IP->Key mappings from userspace */
2671                err = tp->af_specific->md5_parse(sk, optval, optlen);
2672                break;
2673#endif
2674        case TCP_USER_TIMEOUT:
2675                /* Cap the max timeout in ms TCP will retry/retrans
2676                 * before giving up and aborting (ETIMEDOUT) a connection.
2677                 */
2678                if (val < 0)
2679                        err = -EINVAL;
2680                else
2681                        icsk->icsk_user_timeout = msecs_to_jiffies(val);
2682                break;
2683
2684        case TCP_FASTOPEN:
2685                if (val >= 0 && ((1 << sk->sk_state) & (TCPF_CLOSE |
2686                    TCPF_LISTEN)))
2687                        err = fastopen_init_queue(sk, val);
2688                else
2689                        err = -EINVAL;
2690                break;
2691        case TCP_TIMESTAMP:
2692                if (!tp->repair)
2693                        err = -EPERM;
2694                else
2695                        tp->tsoffset = val - tcp_time_stamp;
2696                break;
2697        case TCP_NOTSENT_LOWAT:
2698                tp->notsent_lowat = val;
2699                sk->sk_write_space(sk);
2700                break;
2701        default:
2702                err = -ENOPROTOOPT;
2703                break;
2704        }
2705
2706        release_sock(sk);
2707        return err;
2708}
2709
2710int tcp_setsockopt(struct sock *sk, int level, int optname, char __user *optval,
2711                   unsigned int optlen)
2712{
2713        const struct inet_connection_sock *icsk = inet_csk(sk);
2714
2715        if (level != SOL_TCP)
2716                return icsk->icsk_af_ops->setsockopt(sk, level, optname,
2717                                                     optval, optlen);
2718        return do_tcp_setsockopt(sk, level, optname, optval, optlen);
2719}
2720EXPORT_SYMBOL(tcp_setsockopt);
2721
2722#ifdef CONFIG_COMPAT
2723int compat_tcp_setsockopt(struct sock *sk, int level, int optname,
2724                          char __user *optval, unsigned int optlen)
2725{
2726        if (level != SOL_TCP)
2727                return inet_csk_compat_setsockopt(sk, level, optname,
2728                                                  optval, optlen);
2729        return do_tcp_setsockopt(sk, level, optname, optval, optlen);
2730}
2731EXPORT_SYMBOL(compat_tcp_setsockopt);
2732#endif
2733
2734/* Return information about state of tcp endpoint in API format. */
2735void tcp_get_info(const struct sock *sk, struct tcp_info *info)
2736{
2737        const struct tcp_sock *tp = tcp_sk(sk);
2738        const struct inet_connection_sock *icsk = inet_csk(sk);
2739        u32 now = tcp_time_stamp;
2740
2741        memset(info, 0, sizeof(*info));
2742
2743        info->tcpi_state = sk->sk_state;
2744        info->tcpi_ca_state = icsk->icsk_ca_state;
2745        info->tcpi_retransmits = icsk->icsk_retransmits;
2746        info->tcpi_probes = icsk->icsk_probes_out;
2747        info->tcpi_backoff = icsk->icsk_backoff;
2748
2749        if (tp->rx_opt.tstamp_ok)
2750                info->tcpi_options |= TCPI_OPT_TIMESTAMPS;
2751        if (tcp_is_sack(tp))
2752                info->tcpi_options |= TCPI_OPT_SACK;
2753        if (tp->rx_opt.wscale_ok) {
2754                info->tcpi_options |= TCPI_OPT_WSCALE;
2755                info->tcpi_snd_wscale = tp->rx_opt.snd_wscale;
2756                info->tcpi_rcv_wscale = tp->rx_opt.rcv_wscale;
2757        }
2758
2759        if (tp->ecn_flags & TCP_ECN_OK)
2760                info->tcpi_options |= TCPI_OPT_ECN;
2761        if (tp->ecn_flags & TCP_ECN_SEEN)
2762                info->tcpi_options |= TCPI_OPT_ECN_SEEN;
2763        if (tp->syn_data_acked)
2764                info->tcpi_options |= TCPI_OPT_SYN_DATA;
2765
2766        info->tcpi_rto = jiffies_to_usecs(icsk->icsk_rto);
2767        info->tcpi_ato = jiffies_to_usecs(icsk->icsk_ack.ato);
2768        info->tcpi_snd_mss = tp->mss_cache;
2769        info->tcpi_rcv_mss = icsk->icsk_ack.rcv_mss;
2770
2771        if (sk->sk_state == TCP_LISTEN) {
2772                info->tcpi_unacked = sk->sk_ack_backlog;
2773                info->tcpi_sacked = sk->sk_max_ack_backlog;
2774        } else {
2775                info->tcpi_unacked = tp->packets_out;
2776                info->tcpi_sacked = tp->sacked_out;
2777        }
2778        info->tcpi_lost = tp->lost_out;
2779        info->tcpi_retrans = tp->retrans_out;
2780        info->tcpi_fackets = tp->fackets_out;
2781
2782        info->tcpi_last_data_sent = jiffies_to_msecs(now - tp->lsndtime);
2783        info->tcpi_last_data_recv = jiffies_to_msecs(now - icsk->icsk_ack.lrcvtime);
2784        info->tcpi_last_ack_recv = jiffies_to_msecs(now - tp->rcv_tstamp);
2785
2786        info->tcpi_pmtu = icsk->icsk_pmtu_cookie;
2787        info->tcpi_rcv_ssthresh = tp->rcv_ssthresh;
2788        info->tcpi_rtt = jiffies_to_usecs(tp->srtt)>>3;
2789        info->tcpi_rttvar = jiffies_to_usecs(tp->mdev)>>2;
2790        info->tcpi_snd_ssthresh = tp->snd_ssthresh;
2791        info->tcpi_snd_cwnd = tp->snd_cwnd;
2792        info->tcpi_advmss = tp->advmss;
2793        info->tcpi_reordering = tp->reordering;
2794
2795        info->tcpi_rcv_rtt = jiffies_to_usecs(tp->rcv_rtt_est.rtt)>>3;
2796        info->tcpi_rcv_space = tp->rcvq_space.space;
2797
2798        info->tcpi_total_retrans = tp->total_retrans;
2799}
2800EXPORT_SYMBOL_GPL(tcp_get_info);
2801
2802static int do_tcp_getsockopt(struct sock *sk, int level,
2803                int optname, char __user *optval, int __user *optlen)
2804{
2805        struct inet_connection_sock *icsk = inet_csk(sk);
2806        struct tcp_sock *tp = tcp_sk(sk);
2807        int val, len;
2808
2809        if (get_user(len, optlen))
2810                return -EFAULT;
2811
2812        len = min_t(unsigned int, len, sizeof(int));
2813
2814        if (len < 0)
2815                return -EINVAL;
2816
2817        switch (optname) {
2818        case TCP_MAXSEG:
2819                val = tp->mss_cache;
2820                if (!val && ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN)))
2821                        val = tp->rx_opt.user_mss;
2822                if (tp->repair)
2823                        val = tp->rx_opt.mss_clamp;
2824                break;
2825        case TCP_NODELAY:
2826                val = !!(tp->nonagle&TCP_NAGLE_OFF);
2827                break;
2828        case TCP_CORK:
2829                val = !!(tp->nonagle&TCP_NAGLE_CORK);
2830                break;
2831        case TCP_KEEPIDLE:
2832                val = keepalive_time_when(tp) / HZ;
2833                break;
2834        case TCP_KEEPINTVL:
2835                val = keepalive_intvl_when(tp) / HZ;
2836                break;
2837        case TCP_KEEPCNT:
2838                val = keepalive_probes(tp);
2839                break;
2840        case TCP_SYNCNT:
2841                val = icsk->icsk_syn_retries ? : sysctl_tcp_syn_retries;
2842                break;
2843        case TCP_LINGER2:
2844                val = tp->linger2;
2845                if (val >= 0)
2846                        val = (val ? : sysctl_tcp_fin_timeout) / HZ;
2847                break;
2848        case TCP_DEFER_ACCEPT:
2849                val = retrans_to_secs(icsk->icsk_accept_queue.rskq_defer_accept,
2850                                      TCP_TIMEOUT_INIT / HZ, TCP_RTO_MAX / HZ);
2851                break;
2852        case TCP_WINDOW_CLAMP:
2853                val = tp->window_clamp;
2854                break;
2855        case TCP_INFO: {
2856                struct tcp_info info;
2857
2858                if (get_user(len, optlen))
2859                        return -EFAULT;
2860
2861                tcp_get_info(sk, &info);
2862
2863                len = min_t(unsigned int, len, sizeof(info));
2864                if (put_user(len, optlen))
2865                        return -EFAULT;
2866                if (copy_to_user(optval, &info, len))
2867                        return -EFAULT;
2868                return 0;
2869        }
2870        case TCP_QUICKACK:
2871                val = !icsk->icsk_ack.pingpong;
2872                break;
2873
2874        case TCP_CONGESTION:
2875                if (get_user(len, optlen))
2876                        return -EFAULT;
2877                len = min_t(unsigned int, len, TCP_CA_NAME_MAX);
2878                if (put_user(len, optlen))
2879                        return -EFAULT;
2880                if (copy_to_user(optval, icsk->icsk_ca_ops->name, len))
2881                        return -EFAULT;
2882                return 0;
2883
2884        case TCP_THIN_LINEAR_TIMEOUTS:
2885                val = tp->thin_lto;
2886                break;
2887        case TCP_THIN_DUPACK:
2888                val = tp->thin_dupack;
2889                break;
2890
2891        case TCP_REPAIR:
2892                val = tp->repair;
2893                break;
2894
2895        case TCP_REPAIR_QUEUE:
2896                if (tp->repair)
2897                        val = tp->repair_queue;
2898                else
2899                        return -EINVAL;
2900                break;
2901
2902        case TCP_QUEUE_SEQ:
2903                if (tp->repair_queue == TCP_SEND_QUEUE)
2904                        val = tp->write_seq;
2905                else if (tp->repair_queue == TCP_RECV_QUEUE)
2906                        val = tp->rcv_nxt;
2907                else
2908                        return -EINVAL;
2909                break;
2910
2911        case TCP_USER_TIMEOUT:
2912                val = jiffies_to_msecs(icsk->icsk_user_timeout);
2913                break;
2914        case TCP_TIMESTAMP:
2915                val = tcp_time_stamp + tp->tsoffset;
2916                break;
2917        case TCP_NOTSENT_LOWAT:
2918                val = tp->notsent_lowat;
2919                break;
2920        default:
2921                return -ENOPROTOOPT;
2922        }
2923
2924        if (put_user(len, optlen))
2925                return -EFAULT;
2926        if (copy_to_user(optval, &val, len))
2927                return -EFAULT;
2928        return 0;
2929}
2930
2931int tcp_getsockopt(struct sock *sk, int level, int optname, char __user *optval,
2932                   int __user *optlen)
2933{
2934        struct inet_connection_sock *icsk = inet_csk(sk);
2935
2936        if (level != SOL_TCP)
2937                return icsk->icsk_af_ops->getsockopt(sk, level, optname,
2938                                                     optval, optlen);
2939        return do_tcp_getsockopt(sk, level, optname, optval, optlen);
2940}
2941EXPORT_SYMBOL(tcp_getsockopt);
2942
2943#ifdef CONFIG_COMPAT
2944int compat_tcp_getsockopt(struct sock *sk, int level, int optname,
2945                          char __user *optval, int __user *optlen)
2946{
2947        if (level != SOL_TCP)
2948                return inet_csk_compat_getsockopt(sk, level, optname,
2949                                                  optval, optlen);
2950        return do_tcp_getsockopt(sk, level, optname, optval, optlen);
2951}
2952EXPORT_SYMBOL(compat_tcp_getsockopt);
2953#endif
2954
2955#ifdef CONFIG_TCP_MD5SIG
2956static struct tcp_md5sig_pool __percpu *tcp_md5sig_pool __read_mostly;
2957static DEFINE_MUTEX(tcp_md5sig_mutex);
2958
2959static void __tcp_free_md5sig_pool(struct tcp_md5sig_pool __percpu *pool)
2960{
2961        int cpu;
2962
2963        for_each_possible_cpu(cpu) {
2964                struct tcp_md5sig_pool *p = per_cpu_ptr(pool, cpu);
2965
2966                if (p->md5_desc.tfm)
2967                        crypto_free_hash(p->md5_desc.tfm);
2968        }
2969        free_percpu(pool);
2970}
2971
2972static void __tcp_alloc_md5sig_pool(void)
2973{
2974        int cpu;
2975        struct tcp_md5sig_pool __percpu *pool;
2976
2977        pool = alloc_percpu(struct tcp_md5sig_pool);
2978        if (!pool)
2979                return;
2980
2981        for_each_possible_cpu(cpu) {
2982                struct crypto_hash *hash;
2983
2984                hash = crypto_alloc_hash("md5", 0, CRYPTO_ALG_ASYNC);
2985                if (IS_ERR_OR_NULL(hash))
2986                        goto out_free;
2987
2988                per_cpu_ptr(pool, cpu)->md5_desc.tfm = hash;
2989        }
2990        /* before setting tcp_md5sig_pool, we must commit all writes
2991         * to memory. See ACCESS_ONCE() in tcp_get_md5sig_pool()
2992         */
2993        smp_wmb();
2994        tcp_md5sig_pool = pool;
2995        return;
2996out_free:
2997        __tcp_free_md5sig_pool(pool);
2998}
2999
3000bool tcp_alloc_md5sig_pool(void)
3001{
3002        if (unlikely(!tcp_md5sig_pool)) {
3003                mutex_lock(&tcp_md5sig_mutex);
3004
3005                if (!tcp_md5sig_pool)
3006                        __tcp_alloc_md5sig_pool();
3007
3008                mutex_unlock(&tcp_md5sig_mutex);
3009        }
3010        return tcp_md5sig_pool != NULL;
3011}
3012EXPORT_SYMBOL(tcp_alloc_md5sig_pool);
3013
3014
3015/**
3016 *      tcp_get_md5sig_pool - get md5sig_pool for this user
3017 *
3018 *      We use percpu structure, so if we succeed, we exit with preemption
3019 *      and BH disabled, to make sure another thread or softirq handling
3020 *      wont try to get same context.
3021 */
3022struct tcp_md5sig_pool *tcp_get_md5sig_pool(void)
3023{
3024        struct tcp_md5sig_pool __percpu *p;
3025
3026        local_bh_disable();
3027        p = ACCESS_ONCE(tcp_md5sig_pool);
3028        if (p)
3029                return __this_cpu_ptr(p);
3030
3031        local_bh_enable();
3032        return NULL;
3033}
3034EXPORT_SYMBOL(tcp_get_md5sig_pool);
3035
3036int tcp_md5_hash_header(struct tcp_md5sig_pool *hp,
3037                        const struct tcphdr *th)
3038{
3039        struct scatterlist sg;
3040        struct tcphdr hdr;
3041        int err;
3042
3043        /* We are not allowed to change tcphdr, make a local copy */
3044        memcpy(&hdr, th, sizeof(hdr));
3045        hdr.check = 0;
3046
3047        /* options aren't included in the hash */
3048        sg_init_one(&sg, &hdr, sizeof(hdr));
3049        err = crypto_hash_update(&hp->md5_desc, &sg, sizeof(hdr));
3050        return err;
3051}
3052EXPORT_SYMBOL(tcp_md5_hash_header);
3053
3054int tcp_md5_hash_skb_data(struct tcp_md5sig_pool *hp,
3055                          const struct sk_buff *skb, unsigned int header_len)
3056{
3057        struct scatterlist sg;
3058        const struct tcphdr *tp = tcp_hdr(skb);
3059        struct hash_desc *desc = &hp->md5_desc;
3060        unsigned int i;
3061        const unsigned int head_data_len = skb_headlen(skb) > header_len ?
3062                                           skb_headlen(skb) - header_len : 0;
3063        const struct skb_shared_info *shi = skb_shinfo(skb);
3064        struct sk_buff *frag_iter;
3065
3066        sg_init_table(&sg, 1);
3067
3068        sg_set_buf(&sg, ((u8 *) tp) + header_len, head_data_len);
3069        if (crypto_hash_update(desc, &sg, head_data_len))
3070                return 1;
3071
3072        for (i = 0; i < shi->nr_frags; ++i) {
3073                const struct skb_frag_struct *f = &shi->frags[i];
3074                unsigned int offset = f->page_offset;
3075                struct page *page = skb_frag_page(f) + (offset >> PAGE_SHIFT);
3076
3077                sg_set_page(&sg, page, skb_frag_size(f),
3078                            offset_in_page(offset));
3079                if (crypto_hash_update(desc, &sg, skb_frag_size(f)))
3080                        return 1;
3081        }
3082
3083        skb_walk_frags(skb, frag_iter)
3084                if (tcp_md5_hash_skb_data(hp, frag_iter, 0))
3085                        return 1;
3086
3087        return 0;
3088}
3089EXPORT_SYMBOL(tcp_md5_hash_skb_data);
3090
3091int tcp_md5_hash_key(struct tcp_md5sig_pool *hp, const struct tcp_md5sig_key *key)
3092{
3093        struct scatterlist sg;
3094
3095        sg_init_one(&sg, key->key, key->keylen);
3096        return crypto_hash_update(&hp->md5_desc, &sg, key->keylen);
3097}
3098EXPORT_SYMBOL(tcp_md5_hash_key);
3099
3100#endif
3101
3102void tcp_done(struct sock *sk)
3103{
3104        struct request_sock *req = tcp_sk(sk)->fastopen_rsk;
3105
3106        if (sk->sk_state == TCP_SYN_SENT || sk->sk_state == TCP_SYN_RECV)
3107                TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_ATTEMPTFAILS);
3108
3109        tcp_set_state(sk, TCP_CLOSE);
3110        tcp_clear_xmit_timers(sk);
3111        if (req != NULL)
3112                reqsk_fastopen_remove(sk, req, false);
3113
3114        sk->sk_shutdown = SHUTDOWN_MASK;
3115
3116        if (!sock_flag(sk, SOCK_DEAD))
3117                sk->sk_state_change(sk);
3118        else
3119                inet_csk_destroy_sock(sk);
3120}
3121EXPORT_SYMBOL_GPL(tcp_done);
3122
3123extern struct tcp_congestion_ops tcp_reno;
3124
3125static __initdata unsigned long thash_entries;
3126static int __init set_thash_entries(char *str)
3127{
3128        ssize_t ret;
3129
3130        if (!str)
3131                return 0;
3132
3133        ret = kstrtoul(str, 0, &thash_entries);
3134        if (ret)
3135                return 0;
3136
3137        return 1;
3138}
3139__setup("thash_entries=", set_thash_entries);
3140
3141static void tcp_init_mem(void)
3142{
3143        unsigned long limit = nr_free_buffer_pages() / 8;
3144        limit = max(limit, 128UL);
3145        sysctl_tcp_mem[0] = limit / 4 * 3;
3146        sysctl_tcp_mem[1] = limit;
3147        sysctl_tcp_mem[2] = sysctl_tcp_mem[0] * 2;
3148}
3149
3150void __init tcp_init(void)
3151{
3152        struct sk_buff *skb = NULL;
3153        unsigned long limit;
3154        int max_rshare, max_wshare, cnt;
3155        unsigned int i;
3156
3157        BUILD_BUG_ON(sizeof(struct tcp_skb_cb) > sizeof(skb->cb));
3158
3159        percpu_counter_init(&tcp_sockets_allocated, 0);
3160        percpu_counter_init(&tcp_orphan_count, 0);
3161        tcp_hashinfo.bind_bucket_cachep =
3162                kmem_cache_create("tcp_bind_bucket",
3163                                  sizeof(struct inet_bind_bucket), 0,
3164                                  SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
3165
3166        /* Size and allocate the main established and bind bucket
3167         * hash tables.
3168         *
3169         * The methodology is similar to that of the buffer cache.
3170         */
3171        tcp_hashinfo.ehash =
3172                alloc_large_system_hash("TCP established",
3173                                        sizeof(struct inet_ehash_bucket),
3174                                        thash_entries,
3175                                        17, /* one slot per 128 KB of memory */
3176                                        0,
3177                                        NULL,
3178                                        &tcp_hashinfo.ehash_mask,
3179                                        0,
3180                                        thash_entries ? 0 : 512 * 1024);
3181        for (i = 0; i <= tcp_hashinfo.ehash_mask; i++)
3182                INIT_HLIST_NULLS_HEAD(&tcp_hashinfo.ehash[i].chain, i);
3183
3184        if (inet_ehash_locks_alloc(&tcp_hashinfo))
3185                panic("TCP: failed to alloc ehash_locks");
3186        tcp_hashinfo.bhash =
3187                alloc_large_system_hash("TCP bind",
3188                                        sizeof(struct inet_bind_hashbucket),
3189                                        tcp_hashinfo.ehash_mask + 1,
3190                                        17, /* one slot per 128 KB of memory */
3191                                        0,
3192                                        &tcp_hashinfo.bhash_size,
3193                                        NULL,
3194                                        0,
3195                                        64 * 1024);
3196        tcp_hashinfo.bhash_size = 1U << tcp_hashinfo.bhash_size;
3197        for (i = 0; i < tcp_hashinfo.bhash_size; i++) {
3198                spin_lock_init(&tcp_hashinfo.bhash[i].lock);
3199                INIT_HLIST_HEAD(&tcp_hashinfo.bhash[i].chain);
3200        }
3201
3202
3203        cnt = tcp_hashinfo.ehash_mask + 1;
3204
3205        tcp_death_row.sysctl_max_tw_buckets = cnt / 2;
3206        sysctl_tcp_max_orphans = cnt / 2;
3207        sysctl_max_syn_backlog = max(128, cnt / 256);
3208
3209        tcp_init_mem();
3210        /* Set per-socket limits to no more than 1/128 the pressure threshold */
3211        limit = nr_free_buffer_pages() << (PAGE_SHIFT - 7);
3212        max_wshare = min(4UL*1024*1024, limit);
3213        max_rshare = min(6UL*1024*1024, limit);
3214
3215        sysctl_tcp_wmem[0] = SK_MEM_QUANTUM;
3216        sysctl_tcp_wmem[1] = 16*1024;
3217        sysctl_tcp_wmem[2] = max(64*1024, max_wshare);
3218
3219        sysctl_tcp_rmem[0] = SK_MEM_QUANTUM;
3220        sysctl_tcp_rmem[1] = 87380;
3221        sysctl_tcp_rmem[2] = max(87380, max_rshare);
3222
3223        pr_info("Hash tables configured (established %u bind %u)\n",
3224                tcp_hashinfo.ehash_mask + 1, tcp_hashinfo.bhash_size);
3225
3226        tcp_metrics_init();
3227
3228        tcp_register_congestion_control(&tcp_reno);
3229
3230        tcp_tasklet_init();
3231}
3232
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