net/ipv4/tcp.c

   1 /*
   2  * INET         An implementation of the TCP/IP protocol suite for the LINUX
   3  *              operating system.  INET is implemented using the  BSD Socket
   4  *              interface as the means of communication with the user level.
   5  *
   6  *              Implementation of the Transmission Control Protocol(TCP).
   7  *
   8  * Authors:     Ross Biro
   9  *              Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
  10  *              Mark Evans, <evansmp@uhura.aston.ac.uk>
  11  *              Corey Minyard <wf-rch!minyard@relay.EU.net>
  12  *              Florian La Roche, <flla@stud.uni-sb.de>
  13  *              Charles Hedrick, <hedrick@klinzhai.rutgers.edu>
  14  *              Linus Torvalds, <torvalds@cs.helsinki.fi>
  15  *              Alan Cox, <gw4pts@gw4pts.ampr.org>
  16  *              Matthew Dillon, <dillon@apollo.west.oic.com>
  17  *              Arnt Gulbrandsen, <agulbra@nvg.unit.no>
  18  *              Jorge Cwik, <jorge@laser.satlink.net>
  19  *
  20  * Fixes:
  21  *              Alan Cox        :       Numerous verify_area() calls
  22  *              Alan Cox        :       Set the ACK bit on a reset
  23  *              Alan Cox        :       Stopped it crashing if it closed while
  24  *                                      sk->inuse=1 and was trying to connect
  25  *                                      (tcp_err()).
  26  *              Alan Cox        :       All icmp error handling was broken
  27  *                                      pointers passed where wrong and the
  28  *                                      socket was looked up backwards. Nobody
  29  *                                      tested any icmp error code obviously.
  30  *              Alan Cox        :       tcp_err() now handled properly. It
  31  *                                      wakes people on errors. poll
  32  *                                      behaves and the icmp error race
  33  *                                      has gone by moving it into sock.c
  34  *              Alan Cox        :       tcp_send_reset() fixed to work for
  35  *                                      everything not just packets for
  36  *                                      unknown sockets.
  37  *              Alan Cox        :       tcp option processing.
  38  *              Alan Cox        :       Reset tweaked (still not 100%) [Had
  39  *                                      syn rule wrong]
  40  *              Herp Rosmanith  :       More reset fixes
  41  *              Alan Cox        :       No longer acks invalid rst frames.
  42  *                                      Acking any kind of RST is right out.
  43  *              Alan Cox        :       Sets an ignore me flag on an rst
  44  *                                      receive otherwise odd bits of prattle
  45  *                                      escape still
  46  *              Alan Cox        :       Fixed another acking RST frame bug.
  47  *                                      Should stop LAN workplace lockups.
  48  *              Alan Cox        :       Some tidyups using the new skb list
  49  *                                      facilities
  50  *              Alan Cox        :       sk->keepopen now seems to work
  51  *              Alan Cox        :       Pulls options out correctly on accepts
  52  *              Alan Cox        :       Fixed assorted sk->rqueue->next errors
  53  *              Alan Cox        :       PSH doesn't end a TCP read. Switched a
  54  *                                      bit to skb ops.
  55  *              Alan Cox        :       Tidied tcp_data to avoid a potential
  56  *                                      nasty.
  57  *              Alan Cox        :       Added some better commenting, as the
  58  *                                      tcp is hard to follow
  59  *              Alan Cox        :       Removed incorrect check for 20 * psh
  60  *      Michael O'Reilly        :       ack < copied bug fix.
  61  *      Johannes Stille         :       Misc tcp fixes (not all in yet).
  62  *              Alan Cox        :       FIN with no memory -> CRASH
  63  *              Alan Cox        :       Added socket option proto entries.
  64  *                                      Also added awareness of them to accept.
  65  *              Alan Cox        :       Added TCP options (SOL_TCP)
  66  *              Alan Cox        :       Switched wakeup calls to callbacks,
  67  *                                      so the kernel can layer network
  68  *                                      sockets.
  69  *              Alan Cox        :       Use ip_tos/ip_ttl settings.
  70  *              Alan Cox        :       Handle FIN (more) properly (we hope).
  71  *              Alan Cox        :       RST frames sent on unsynchronised
  72  *                                      state ack error.
  73  *              Alan Cox        :       Put in missing check for SYN bit.
  74  *              Alan Cox        :       Added tcp_select_window() aka NET2E
  75  *                                      window non shrink trick.
  76  *              Alan Cox        :       Added a couple of small NET2E timer
  77  *                                      fixes
  78  *              Charles Hedrick :       TCP fixes
  79  *              Toomas Tamm     :       TCP window fixes
  80  *              Alan Cox        :       Small URG fix to rlogin ^C ack fight
  81  *              Charles Hedrick :       Rewrote most of it to actually work
  82  *              Linus           :       Rewrote tcp_read() and URG handling
  83  *                                      completely
  84  *              Gerhard Koerting:       Fixed some missing timer handling
  85  *              Matthew Dillon  :       Reworked TCP machine states as per RFC
  86  *              Gerhard Koerting:       PC/TCP workarounds
  87  *              Adam Caldwell   :       Assorted timer/timing errors
  88  *              Matthew Dillon  :       Fixed another RST bug
  89  *              Alan Cox        :       Move to kernel side addressing changes.
  90  *              Alan Cox        :       Beginning work on TCP fastpathing
  91  *                                      (not yet usable)
  92  *              Arnt Gulbrandsen:       Turbocharged tcp_check() routine.
  93  *              Alan Cox        :       TCP fast path debugging
  94  *              Alan Cox        :       Window clamping
  95  *              Michael Riepe   :       Bug in tcp_check()
  96  *              Matt Dillon     :       More TCP improvements and RST bug fixes
  97  *              Matt Dillon     :       Yet more small nasties remove from the
  98  *                                      TCP code (Be very nice to this man if
  99  *                                      tcp finally works 100%) 8)
 100  *              Alan Cox        :       BSD accept semantics.
 101  *              Alan Cox        :       Reset on closedown bug.
 102  *      Peter De Schrijver      :       ENOTCONN check missing in tcp_sendto().
 103  *              Michael Pall    :       Handle poll() after URG properly in
 104  *                                      all cases.
 105  *              Michael Pall    :       Undo the last fix in tcp_read_urg()
 106  *                                      (multi URG PUSH broke rlogin).
 107  *              Michael Pall    :       Fix the multi URG PUSH problem in
 108  *                                      tcp_readable(), poll() after URG
 109  *                                      works now.
 110  *              Michael Pall    :       recv(...,MSG_OOB) never blocks in the
 111  *                                      BSD api.
 112  *              Alan Cox        :       Changed the semantics of sk->socket to
 113  *                                      fix a race and a signal problem with
 114  *                                      accept() and async I/O.
 115  *              Alan Cox        :       Relaxed the rules on tcp_sendto().
 116  *              Yury Shevchuk   :       Really fixed accept() blocking problem.
 117  *              Craig I. Hagan  :       Allow for BSD compatible TIME_WAIT for
 118  *                                      clients/servers which listen in on
 119  *                                      fixed ports.
 120  *              Alan Cox        :       Cleaned the above up and shrank it to
 121  *                                      a sensible code size.
 122  *              Alan Cox        :       Self connect lockup fix.
 123  *              Alan Cox        :       No connect to multicast.
 124  *              Ross Biro       :       Close unaccepted children on master
 125  *                                      socket close.
 126  *              Alan Cox        :       Reset tracing code.
 127  *              Alan Cox        :       Spurious resets on shutdown.
 128  *              Alan Cox        :       Giant 15 minute/60 second timer error
 129  *              Alan Cox        :       Small whoops in polling before an
 130  *                                      accept.
 131  *              Alan Cox        :       Kept the state trace facility since
 132  *                                      it's handy for debugging.
 133  *              Alan Cox        :       More reset handler fixes.
 134  *              Alan Cox        :       Started rewriting the code based on
 135  *                                      the RFC's for other useful protocol
 136  *                                      references see: Comer, KA9Q NOS, and
 137  *                                      for a reference on the difference
 138  *                                      between specifications and how BSD
 139  *                                      works see the 4.4lite source.
 140  *              A.N.Kuznetsov   :       Don't time wait on completion of tidy
 141  *                                      close.
 142  *              Linus Torvalds  :       Fin/Shutdown & copied_seq changes.
 143  *              Linus Torvalds  :       Fixed BSD port reuse to work first syn
 144  *              Alan Cox        :       Reimplemented timers as per the RFC
 145  *                                      and using multiple timers for sanity.
 146  *              Alan Cox        :       Small bug fixes, and a lot of new
 147  *                                      comments.
 148  *              Alan Cox        :       Fixed dual reader crash by locking
 149  *                                      the buffers (much like datagram.c)
 150  *              Alan Cox        :       Fixed stuck sockets in probe. A probe
 151  *                                      now gets fed up of retrying without
 152  *                                      (even a no space) answer.
 153  *              Alan Cox        :       Extracted closing code better
 154  *              Alan Cox        :       Fixed the closing state machine to
 155  *                                      resemble the RFC.
 156  *              Alan Cox        :       More 'per spec' fixes.
 157  *              Jorge Cwik      :       Even faster checksumming.
 158  *              Alan Cox        :       tcp_data() doesn't ack illegal PSH
 159  *                                      only frames. At least one pc tcp stack
 160  *                                      generates them.
 161  *              Alan Cox        :       Cache last socket.
 162  *              Alan Cox        :       Per route irtt.
 163  *              Matt Day        :       poll()->select() match BSD precisely on error
 164  *              Alan Cox        :       New buffers
 165  *              Marc Tamsky     :       Various sk->prot->retransmits and
 166  *                                      sk->retransmits misupdating fixed.
 167  *                                      Fixed tcp_write_timeout: stuck close,
 168  *                                      and TCP syn retries gets used now.
 169  *              Mark Yarvis     :       In tcp_read_wakeup(), don't send an
 170  *                                      ack if state is TCP_CLOSED.
 171  *              Alan Cox        :       Look up device on a retransmit - routes may
 172  *                                      change. Doesn't yet cope with MSS shrink right
 173  *                                      but it's a start!
 174  *              Marc Tamsky     :       Closing in closing fixes.
 175  *              Mike Shaver     :       RFC1122 verifications.
 176  *              Alan Cox        :       rcv_saddr errors.
 177  *              Alan Cox        :       Block double connect().
 178  *              Alan Cox        :       Small hooks for enSKIP.
 179  *              Alexey Kuznetsov:       Path MTU discovery.
 180  *              Alan Cox        :       Support soft errors.
 181  *              Alan Cox        :       Fix MTU discovery pathological case
 182  *                                      when the remote claims no mtu!
 183  *              Marc Tamsky     :       TCP_CLOSE fix.
 184  *              Colin (G3TNE)   :       Send a reset on syn ack replies in
 185  *                                      window but wrong (fixes NT lpd problems)
 186  *              Pedro Roque     :       Better TCP window handling, delayed ack.
 187  *              Joerg Reuter    :       No modification of locked buffers in
 188  *                                      tcp_do_retransmit()
 189  *              Eric Schenk     :       Changed receiver side silly window
 190  *                                      avoidance algorithm to BSD style
 191  *                                      algorithm. This doubles throughput
 192  *                                      against machines running Solaris,
 193  *                                      and seems to result in general
 194  *                                      improvement.
 195  *      Stefan Magdalinski      :       adjusted tcp_readable() to fix FIONREAD
 196  *      Willy Konynenberg       :       Transparent proxying support.
 197  *      Mike McLagan            :       Routing by source
 198  *              Keith Owens     :       Do proper merging with partial SKB's in
 199  *                                      tcp_do_sendmsg to avoid burstiness.
 200  *              Eric Schenk     :       Fix fast close down bug with
 201  *                                      shutdown() followed by close().
 202  *              Andi Kleen      :       Make poll agree with SIGIO
 203  *      Salvatore Sanfilippo    :       Support SO_LINGER with linger == 1 and
 204  *                                      lingertime == 0 (RFC 793 ABORT Call)
 205  *      Hirokazu Takahashi      :       Use copy_from_user() instead of
 206  *                                      csum_and_copy_from_user() if possible.
 207  *
 208  *              This program is free software; you can redistribute it and/or
 209  *              modify it under the terms of the GNU General Public License
 210  *              as published by the Free Software Foundation; either version
 211  *              2 of the License, or(at your option) any later version.
 212  *
 213  * Description of States:
 214  *
 215  *      TCP_SYN_SENT            sent a connection request, waiting for ack
 216  *
 217  *      TCP_SYN_RECV            received a connection request, sent ack,
 218  *                              waiting for final ack in three-way handshake.
 219  *
 220  *      TCP_ESTABLISHED         connection established
 221  *
 222  *      TCP_FIN_WAIT1           our side has shutdown, waiting to complete
 223  *                              transmission of remaining buffered data
 224  *
 225  *      TCP_FIN_WAIT2           all buffered data sent, waiting for remote
 226  *                              to shutdown
 227  *
 228  *      TCP_CLOSING             both sides have shutdown but we still have
 229  *                              data we have to finish sending
 230  *
 231  *      TCP_TIME_WAIT           timeout to catch resent junk before entering
 232  *                              closed, can only be entered from FIN_WAIT2
 233  *                              or CLOSING.  Required because the other end
 234  *                              may not have gotten our last ACK causing it
 235  *                              to retransmit the data packet (which we ignore)
 236  *
 237  *      TCP_CLOSE_WAIT          remote side has shutdown and is waiting for
 238  *                              us to finish writing our data and to shutdown
 239  *                              (we have to close() to move on to LAST_ACK)
 240  *
 241  *      TCP_LAST_ACK            out side has shutdown after remote has
 242  *                              shutdown.  There may still be data in our
 243  *                              buffer that we have to finish sending
 244  *
 245  *      TCP_CLOSE               socket is finished
 246  */
 247
 248 #include <linux/kernel.h>
 249 #include <linux/module.h>
 250 #include <linux/types.h>
 251 #include <linux/fcntl.h>
 252 #include <linux/poll.h>
 253 #include <linux/init.h>
 254 #include <linux/fs.h>
 255 #include <linux/skbuff.h>
 256 #include <linux/scatterlist.h>
 257 #include <linux/splice.h>
 258 #include <linux/net.h>
 259 #include <linux/socket.h>
 260 #include <linux/random.h>
 261 #include <linux/bootmem.h>
 262 #include <linux/highmem.h>
 263 #include <linux/swap.h>
 264 #include <linux/cache.h>
 265 #include <linux/err.h>
 266 #include <linux/crypto.h>
 267 #include <linux/time.h>
 268 #include <linux/slab.h>
 269
 270 #include <net/icmp.h>
 271 #include <net/tcp.h>
 272 #include <net/xfrm.h>
 273 #include <net/ip.h>
 274 #include <net/netdma.h>
 275 #include <net/sock.h>
 276
 277 #include <asm/uaccess.h>
 278 #include <asm/ioctls.h>
 279
 280 int sysctl_tcp_fin_timeout __read_mostly = TCP_FIN_TIMEOUT;
 281
 282 struct percpu_counter tcp_orphan_count;
 283 EXPORT_SYMBOL_GPL(tcp_orphan_count);
 284
 285 int sysctl_tcp_mem[3] __read_mostly;
 286 int sysctl_tcp_wmem[3] __read_mostly;
 287 int sysctl_tcp_rmem[3] __read_mostly;
 288
 289 EXPORT_SYMBOL(sysctl_tcp_mem);
 290 EXPORT_SYMBOL(sysctl_tcp_rmem);
 291 EXPORT_SYMBOL(sysctl_tcp_wmem);
 292
 293 atomic_t tcp_memory_allocated;  /* Current allocated memory. */
 294 EXPORT_SYMBOL(tcp_memory_allocated);
 295
 296 /*
 297  * Current number of TCP sockets.
 298  */
 299 struct percpu_counter tcp_sockets_allocated;
 300 EXPORT_SYMBOL(tcp_sockets_allocated);
 301
 302 /*
 303  * TCP splice context
 304  */
 305 struct tcp_splice_state {
 306         struct pipe_inode_info *pipe;
 307         size_t len;
 308         unsigned int flags;
 309 };
 310
 311 /*
 312  * Pressure flag: try to collapse.
 313  * Technical note: it is used by multiple contexts non atomically.
 314  * All the __sk_mem_schedule() is of this nature: accounting
 315  * is strict, actions are advisory and have some latency.
 316  */
 317 int tcp_memory_pressure __read_mostly;
 318 EXPORT_SYMBOL(tcp_memory_pressure);
 319
 320 void tcp_enter_memory_pressure(struct sock *sk)
 321 {
 322         if (!tcp_memory_pressure) {
 323                 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMEMORYPRESSURES);
 324                 tcp_memory_pressure = 1;
 325         }
 326 }
 327 EXPORT_SYMBOL(tcp_enter_memory_pressure);
 328
 329 /* Convert seconds to retransmits based on initial and max timeout */
 330 static u8 secs_to_retrans(int seconds, int timeout, int rto_max)
 331 {
 332         u8 res = 0;
 333
 334         if (seconds > 0) {
 335                 int period = timeout;
 336
 337                 res = 1;
 338                 while (seconds > period && res < 255) {
 339                         res++;
 340                         timeout <<= 1;
 341                         if (timeout > rto_max)
 342                                 timeout = rto_max;
 343                         period += timeout;
 344                 }
 345         }
 346         return res;
 347 }
 348
 349 /* Convert retransmits to seconds based on initial and max timeout */
 350 static int retrans_to_secs(u8 retrans, int timeout, int rto_max)
 351 {
 352         int period = 0;
 353
 354         if (retrans > 0) {
 355                 period = timeout;
 356                 while (--retrans) {
 357                         timeout <<= 1;
 358                         if (timeout > rto_max)
 359                                 timeout = rto_max;
 360                         period += timeout;
 361                 }
 362         }
 363         return period;
 364 }
 365
 366 /*
 367  *      Wait for a TCP event.
 368  *
 369  *      Note that we don't need to lock the socket, as the upper poll layers
 370  *      take care of normal races (between the test and the event) and we don't
 371  *      go look at any of the socket buffers directly.
 372  */
 373 unsigned int tcp_poll(struct file *file, struct socket *sock, poll_table *wait)
 374 {
 375         unsigned int mask;
 376         struct sock *sk = sock->sk;
 377         struct tcp_sock *tp = tcp_sk(sk);
 378
 379         sock_poll_wait(file, sk_sleep(sk), wait);
 380         if (sk->sk_state == TCP_LISTEN)
 381                 return inet_csk_listen_poll(sk);
 382
 383         /* Socket is not locked. We are protected from async events
 384          * by poll logic and correct handling of state changes
 385          * made by other threads is impossible in any case.
 386          */
 387
 388         mask = 0;
 389
 390         /*
 391          * POLLHUP is certainly not done right. But poll() doesn't
 392          * have a notion of HUP in just one direction, and for a
 393          * socket the read side is more interesting.
 394          *
 395          * Some poll() documentation says that POLLHUP is incompatible
 396          * with the POLLOUT/POLLWR flags, so somebody should check this
 397          * all. But careful, it tends to be safer to return too many
 398          * bits than too few, and you can easily break real applications
 399          * if you don't tell them that something has hung up!
 400          *
 401          * Check-me.
 402          *
 403          * Check number 1. POLLHUP is _UNMASKABLE_ event (see UNIX98 and
 404          * our fs/select.c). It means that after we received EOF,
 405          * poll always returns immediately, making impossible poll() on write()
 406          * in state CLOSE_WAIT. One solution is evident --- to set POLLHUP
 407          * if and only if shutdown has been made in both directions.
 408          * Actually, it is interesting to look how Solaris and DUX
 409          * solve this dilemma. I would prefer, if POLLHUP were maskable,
 410          * then we could set it on SND_SHUTDOWN. BTW examples given
 411          * in Stevens' books assume exactly this behaviour, it explains
 412          * why POLLHUP is incompatible with POLLOUT.    --ANK
 413          *
 414          * NOTE. Check for TCP_CLOSE is added. The goal is to prevent
 415          * blocking on fresh not-connected or disconnected socket. --ANK
 416          */
 417         if (sk->sk_shutdown == SHUTDOWN_MASK || sk->sk_state == TCP_CLOSE)
 418                 mask |= POLLHUP;
 419         if (sk->sk_shutdown & RCV_SHUTDOWN)
 420                 mask |= POLLIN | POLLRDNORM | POLLRDHUP;
 421
 422         /* Connected? */
 423         if ((1 << sk->sk_state) & ~(TCPF_SYN_SENT | TCPF_SYN_RECV)) {
 424                 int target = sock_rcvlowat(sk, 0, INT_MAX);
 425
 426                 if (tp->urg_seq == tp->copied_seq &&
 427                     !sock_flag(sk, SOCK_URGINLINE) &&
 428                     tp->urg_data)
 429                         target++;
 430
 431                 /* Potential race condition. If read of tp below will
 432                  * escape above sk->sk_state, we can be illegally awaken
 433                  * in SYN_* states. */
 434                 if (tp->rcv_nxt - tp->copied_seq >= target)
 435                         mask |= POLLIN | POLLRDNORM;
 436
 437                 if (!(sk->sk_shutdown & SEND_SHUTDOWN)) {
 438                         if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk)) {
 439                                 mask |= POLLOUT | POLLWRNORM;
 440                         } else {  /* send SIGIO later */
 441                                 set_bit(SOCK_ASYNC_NOSPACE,
 442                                         &sk->sk_socket->flags);
 443                                 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
 444
 445                                 /* Race breaker. If space is freed after
 446                                  * wspace test but before the flags are set,
 447                                  * IO signal will be lost.
 448                                  */
 449                                 if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk))
 450                                         mask |= POLLOUT | POLLWRNORM;
 451                         }
 452                 } else
 453                         mask |= POLLOUT | POLLWRNORM;
 454
 455                 if (tp->urg_data & TCP_URG_VALID)
 456                         mask |= POLLPRI;
 457         }
 458         /* This barrier is coupled with smp_wmb() in tcp_reset() */
 459         smp_rmb();
 460         if (sk->sk_err)
 461                 mask |= POLLERR;
 462
 463         return mask;
 464 }
 465 EXPORT_SYMBOL(tcp_poll);
 466
 467 int tcp_ioctl(struct sock *sk, int cmd, unsigned long arg)
 468 {
 469         struct tcp_sock *tp = tcp_sk(sk);
 470         int answ;
 471
 472         switch (cmd) {
 473         case SIOCINQ:
 474                 if (sk->sk_state == TCP_LISTEN)
 475                         return -EINVAL;
 476
 477                 lock_sock(sk);
 478                 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
 479                         answ = 0;
 480                 else if (sock_flag(sk, SOCK_URGINLINE) ||
 481                          !tp->urg_data ||
 482                          before(tp->urg_seq, tp->copied_seq) ||
 483                          !before(tp->urg_seq, tp->rcv_nxt)) {
 484                         struct sk_buff *skb;
 485
 486                         answ = tp->rcv_nxt - tp->copied_seq;
 487
 488                         /* Subtract 1, if FIN is in queue. */
 489                         skb = skb_peek_tail(&sk->sk_receive_queue);
 490                         if (answ && skb)
 491                                 answ -= tcp_hdr(skb)->fin;
 492                 } else
 493                         answ = tp->urg_seq - tp->copied_seq;
 494                 release_sock(sk);
 495                 break;
 496         case SIOCATMARK:
 497                 answ = tp->urg_data && tp->urg_seq == tp->copied_seq;
 498                 break;
 499         case SIOCOUTQ:
 500                 if (sk->sk_state == TCP_LISTEN)
 501                         return -EINVAL;
 502
 503                 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
 504                         answ = 0;
 505                 else
 506                         answ = tp->write_seq - tp->snd_una;
 507                 break;
 508         default:
 509                 return -ENOIOCTLCMD;
 510         }
 511
 512         return put_user(answ, (int __user *)arg);
 513 }
 514 EXPORT_SYMBOL(tcp_ioctl);
 515
 516 static inline void tcp_mark_push(struct tcp_sock *tp, struct sk_buff *skb)
 517 {
 518         TCP_SKB_CB(skb)->flags |= TCPHDR_PSH;
 519         tp->pushed_seq = tp->write_seq;
 520 }
 521
 522 static inline int forced_push(struct tcp_sock *tp)
 523 {
 524         return after(tp->write_seq, tp->pushed_seq + (tp->max_window >> 1));
 525 }
 526
 527 static inline void skb_entail(struct sock *sk, struct sk_buff *skb)
 528 {
 529         struct tcp_sock *tp = tcp_sk(sk);
 530         struct tcp_skb_cb *tcb = TCP_SKB_CB(skb);
 531
 532         skb->csum    = 0;
 533         tcb->seq     = tcb->end_seq = tp->write_seq;
 534         tcb->flags   = TCPHDR_ACK;
 535         tcb->sacked  = 0;
 536         skb_header_release(skb);
 537         tcp_add_write_queue_tail(sk, skb);
 538         sk->sk_wmem_queued += skb->truesize;
 539         sk_mem_charge(sk, skb->truesize);
 540         if (tp->nonagle & TCP_NAGLE_PUSH)
 541                 tp->nonagle &= ~TCP_NAGLE_PUSH;
 542 }
 543
 544 static inline void tcp_mark_urg(struct tcp_sock *tp, int flags)
 545 {
 546         if (flags & MSG_OOB)
 547                 tp->snd_up = tp->write_seq;
 548 }
 549
 550 static inline void tcp_push(struct sock *sk, int flags, int mss_now,
 551                             int nonagle)
 552 {
 553         if (tcp_send_head(sk)) {
 554                 struct tcp_sock *tp = tcp_sk(sk);
 555
 556                 if (!(flags & MSG_MORE) || forced_push(tp))
 557                         tcp_mark_push(tp, tcp_write_queue_tail(sk));
 558
 559                 tcp_mark_urg(tp, flags);
 560                 __tcp_push_pending_frames(sk, mss_now,
 561                                           (flags & MSG_MORE) ? TCP_NAGLE_CORK : nonagle);
 562         }
 563 }
 564
 565 static int tcp_splice_data_recv(read_descriptor_t *rd_desc, struct sk_buff *skb,
 566                                 unsigned int offset, size_t len)
 567 {
 568         struct tcp_splice_state *tss = rd_desc->arg.data;
 569         int ret;
 570
 571         ret = skb_splice_bits(skb, offset, tss->pipe, min(rd_desc->count, len),
 572                               tss->flags);
 573         if (ret > 0)
 574                 rd_desc->count -= ret;
 575         return ret;
 576 }
 577
 578 static int __tcp_splice_read(struct sock *sk, struct tcp_splice_state *tss)
 579 {
 580         /* Store TCP splice context information in read_descriptor_t. */
 581         read_descriptor_t rd_desc = {
 582                 .arg.data = tss,
 583                 .count    = tss->len,
 584         };
 585
 586         return tcp_read_sock(sk, &rd_desc, tcp_splice_data_recv);
 587 }
 588
 589 /**
 590  *  tcp_splice_read - splice data from TCP socket to a pipe
 591  * @sock:       socket to splice from
 592  * @ppos:       position (not valid)
 593  * @pipe:       pipe to splice to
 594  * @len:        number of bytes to splice
 595  * @flags:      splice modifier flags
 596  *
 597  * Description:
 598  *    Will read pages from given socket and fill them into a pipe.
 599  *
 600  **/
 601 ssize_t tcp_splice_read(struct socket *sock, loff_t *ppos,
 602                         struct pipe_inode_info *pipe, size_t len,
 603                         unsigned int flags)
 604 {
 605         struct sock *sk = sock->sk;
 606         struct tcp_splice_state tss = {
 607                 .pipe = pipe,
 608                 .len = len,
 609                 .flags = flags,
 610         };
 611         long timeo;
 612         ssize_t spliced;
 613         int ret;
 614
 615         sock_rps_record_flow(sk);
 616         /*
 617          * We can't seek on a socket input
 618          */
 619         if (unlikely(*ppos))
 620                 return -ESPIPE;
 621
 622         ret = spliced = 0;
 623
 624         lock_sock(sk);
 625
 626         timeo = sock_rcvtimeo(sk, sock->file->f_flags & O_NONBLOCK);
 627         while (tss.len) {
 628                 ret = __tcp_splice_read(sk, &tss);
 629                 if (ret < 0)
 630                         break;
 631                 else if (!ret) {
 632                         if (spliced)
 633                                 break;
 634                         if (sock_flag(sk, SOCK_DONE))
 635                                 break;
 636                         if (sk->sk_err) {
 637                                 ret = sock_error(sk);
 638                                 break;
 639                         }
 640                         if (sk->sk_shutdown & RCV_SHUTDOWN)
 641                                 break;
 642                         if (sk->sk_state == TCP_CLOSE) {
 643                                 /*
 644                                  * This occurs when user tries to read
 645                                  * from never connected socket.
 646                                  */
 647                                 if (!sock_flag(sk, SOCK_DONE))
 648                                         ret = -ENOTCONN;
 649                                 break;
 650                         }
 651                         if (!timeo) {
 652                                 ret = -EAGAIN;
 653                                 break;
 654                         }
 655                         sk_wait_data(sk, &timeo);
 656                         if (signal_pending(current)) {
 657                                 ret = sock_intr_errno(timeo);
 658                                 break;
 659                         }
 660                         continue;
 661                 }
 662                 tss.len -= ret;
 663                 spliced += ret;
 664
 665                 if (!timeo)
 666                         break;
 667                 release_sock(sk);
 668                 lock_sock(sk);
 669
 670                 if (sk->sk_err || sk->sk_state == TCP_CLOSE ||
 671                     (sk->sk_shutdown & RCV_SHUTDOWN) ||
 672                     signal_pending(current))
 673                         break;
 674         }
 675
 676         release_sock(sk);
 677
 678         if (spliced)
 679                 return spliced;
 680
 681         return ret;
 682 }
 683 EXPORT_SYMBOL(tcp_splice_read);
 684
 685 struct sk_buff *sk_stream_alloc_skb(struct sock *sk, int size, gfp_t gfp)
 686 {
 687         struct sk_buff *skb;
 688
 689         /* The TCP header must be at least 32-bit aligned.  */
 690         size = ALIGN(size, 4);
 691
 692         skb = alloc_skb_fclone(size + sk->sk_prot->max_header, gfp);
 693         if (skb) {
 694                 if (sk_wmem_schedule(sk, skb->truesize)) {
 695                         /*
 696                          * Make sure that we have exactly size bytes
 697                          * available to the caller, no more, no less.
 698                          */
 699                         skb_reserve(skb, skb_tailroom(skb) - size);
 700                         return skb;
 701                 }
 702                 __kfree_skb(skb);
 703         } else {
 704                 sk->sk_prot->enter_memory_pressure(sk);
 705                 sk_stream_moderate_sndbuf(sk);
 706         }
 707         return NULL;
 708 }
 709
 710 static unsigned int tcp_xmit_size_goal(struct sock *sk, u32 mss_now,
 711                                        int large_allowed)
 712 {
 713         struct tcp_sock *tp = tcp_sk(sk);
 714         u32 xmit_size_goal, old_size_goal;
 715
 716         xmit_size_goal = mss_now;
 717
 718         if (large_allowed && sk_can_gso(sk)) {
 719                 xmit_size_goal = ((sk->sk_gso_max_size - 1) -
 720                                   inet_csk(sk)->icsk_af_ops->net_header_len -
 721                                   inet_csk(sk)->icsk_ext_hdr_len -
 722                                   tp->tcp_header_len);
 723
 724                 xmit_size_goal = tcp_bound_to_half_wnd(tp, xmit_size_goal);
 725
 726                 /* We try hard to avoid divides here */
 727                 old_size_goal = tp->xmit_size_goal_segs * mss_now;
 728
 729                 if (likely(old_size_goal <= xmit_size_goal &&
 730                            old_size_goal + mss_now > xmit_size_goal)) {
 731                         xmit_size_goal = old_size_goal;
 732                 } else {
 733                         tp->xmit_size_goal_segs = xmit_size_goal / mss_now;
 734                         xmit_size_goal = tp->xmit_size_goal_segs * mss_now;
 735                 }
 736         }
 737
 738         return max(xmit_size_goal, mss_now);
 739 }
 740
 741 static int tcp_send_mss(struct sock *sk, int *size_goal, int flags)
 742 {
 743         int mss_now;
 744
 745         mss_now = tcp_current_mss(sk);
 746         *size_goal = tcp_xmit_size_goal(sk, mss_now, !(flags & MSG_OOB));
 747
 748         return mss_now;
 749 }
 750
 751 static ssize_t do_tcp_sendpages(struct sock *sk, struct page **pages, int poffset,
 752                          size_t psize, int flags)
 753 {
 754         struct tcp_sock *tp = tcp_sk(sk);
 755         int mss_now, size_goal;
 756         int err;
 757         ssize_t copied;
 758         long timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
 759
 760         /* Wait for a connection to finish. */
 761         if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT))
 762                 if ((err = sk_stream_wait_connect(sk, &timeo)) != 0)
 763                         goto out_err;
 764
 765         clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
 766
 767         mss_now = tcp_send_mss(sk, &size_goal, flags);
 768         copied = 0;
 769
 770         err = -EPIPE;
 771         if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
 772                 goto out_err;
 773
 774         while (psize > 0) {
 775                 struct sk_buff *skb = tcp_write_queue_tail(sk);
 776                 struct page *page = pages[poffset / PAGE_SIZE];
 777                 int copy, i, can_coalesce;
 778                 int offset = poffset % PAGE_SIZE;
 779                 int size = min_t(size_t, psize, PAGE_SIZE - offset);
 780
 781                 if (!tcp_send_head(sk) || (copy = size_goal - skb->len) <= 0) {
 782 new_segment:
 783                         if (!sk_stream_memory_free(sk))
 784                                 goto wait_for_sndbuf;
 785
 786                         skb = sk_stream_alloc_skb(sk, 0, sk->sk_allocation);
 787                         if (!skb)
 788                                 goto wait_for_memory;
 789
 790                         skb_entail(sk, skb);
 791                         copy = size_goal;
 792                 }
 793
 794                 if (copy > size)
 795                         copy = size;
 796
 797                 i = skb_shinfo(skb)->nr_frags;
 798                 can_coalesce = skb_can_coalesce(skb, i, page, offset);
 799                 if (!can_coalesce && i >= MAX_SKB_FRAGS) {
 800                         tcp_mark_push(tp, skb);
 801                         goto new_segment;
 802                 }
 803                 if (!sk_wmem_schedule(sk, copy))
 804                         goto wait_for_memory;
 805
 806                 if (can_coalesce) {
 807                         skb_shinfo(skb)->frags[i - 1].size += copy;
 808                 } else {
 809                         get_page(page);
 810                         skb_fill_page_desc(skb, i, page, offset, copy);
 811                 }
 812
 813                 skb->len += copy;
 814                 skb->data_len += copy;
 815                 skb->truesize += copy;
 816                 sk->sk_wmem_queued += copy;
 817                 sk_mem_charge(sk, copy);
 818                 skb->ip_summed = CHECKSUM_PARTIAL;
 819                 tp->write_seq += copy;
 820                 TCP_SKB_CB(skb)->end_seq += copy;
 821                 skb_shinfo(skb)->gso_segs = 0;
 822
 823                 if (!copied)
 824                         TCP_SKB_CB(skb)->flags &= ~TCPHDR_PSH;
 825
 826                 copied += copy;
 827                 poffset += copy;
 828                 if (!(psize -= copy))
 829                         goto out;
 830
 831                 if (skb->len < size_goal || (flags & MSG_OOB))
 832                         continue;
 833
 834                 if (forced_push(tp)) {
 835                         tcp_mark_push(tp, skb);
 836                         __tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH);
 837                 } else if (skb == tcp_send_head(sk))
 838                         tcp_push_one(sk, mss_now);
 839                 continue;
 840
 841 wait_for_sndbuf:
 842                 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
 843 wait_for_memory:
 844                 if (copied)
 845                         tcp_push(sk, flags & ~MSG_MORE, mss_now, TCP_NAGLE_PUSH);
 846
 847                 if ((err = sk_stream_wait_memory(sk, &timeo)) != 0)
 848                         goto do_error;
 849
 850                 mss_now = tcp_send_mss(sk, &size_goal, flags);
 851         }
 852
 853 out:
 854         if (copied)
 855                 tcp_push(sk, flags, mss_now, tp->nonagle);
 856         return copied;
 857
 858 do_error:
 859         if (copied)
 860                 goto out;
 861 out_err:
 862         return sk_stream_error(sk, flags, err);
 863 }
 864
 865 int tcp_sendpage(struct sock *sk, struct page *page, int offset,
 866                  size_t size, int flags)
 867 {
 868         ssize_t res;
 869
 870         if (!(sk->sk_route_caps & NETIF_F_SG) ||
 871             !(sk->sk_route_caps & NETIF_F_ALL_CSUM))
 872                 return sock_no_sendpage(sk->sk_socket, page, offset, size,
 873                                         flags);
 874
 875         lock_sock(sk);
 876         TCP_CHECK_TIMER(sk);
 877         res = do_tcp_sendpages(sk, &page, offset, size, flags);
 878         TCP_CHECK_TIMER(sk);
 879         release_sock(sk);
 880         return res;
 881 }
 882 EXPORT_SYMBOL(tcp_sendpage);
 883
 884 #define TCP_PAGE(sk)    (sk->sk_sndmsg_page)
 885 #define TCP_OFF(sk)     (sk->sk_sndmsg_off)
 886
 887 static inline int select_size(struct sock *sk, int sg)
 888 {
 889         struct tcp_sock *tp = tcp_sk(sk);
 890         int tmp = tp->mss_cache;
 891
 892         if (sg) {
 893                 if (sk_can_gso(sk))
 894                         tmp = 0;
 895                 else {
 896                         int pgbreak = SKB_MAX_HEAD(MAX_TCP_HEADER);
 897
 898                         if (tmp >= pgbreak &&
 899                             tmp <= pgbreak + (MAX_SKB_FRAGS - 1) * PAGE_SIZE)
 900                                 tmp = pgbreak;
 901                 }
 902         }
 903
 904         return tmp;
 905 }
 906
 907 int tcp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
 908                 size_t size)
 909 {
 910         struct iovec *iov;
 911         struct tcp_sock *tp = tcp_sk(sk);
 912         struct sk_buff *skb;
 913         int iovlen, flags;
 914         int mss_now, size_goal;
 915         int sg, err, copied;
 916         long timeo;
 917
 918         lock_sock(sk);
 919         TCP_CHECK_TIMER(sk);
 920
 921         flags = msg->msg_flags;
 922         timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
 923
 924         /* Wait for a connection to finish. */
 925         if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT))
 926                 if ((err = sk_stream_wait_connect(sk, &timeo)) != 0)
 927                         goto out_err;
 928
 929         /* This should be in poll */
 930         clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
 931
 932         mss_now = tcp_send_mss(sk, &size_goal, flags);
 933
 934         /* Ok commence sending. */
 935         iovlen = msg->msg_iovlen;
 936         iov = msg->msg_iov;
 937         copied = 0;
 938
 939         err = -EPIPE;
 940         if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
 941                 goto out_err;
 942
 943         sg = sk->sk_route_caps & NETIF_F_SG;
 944
 945         while (--iovlen >= 0) {
 946                 size_t seglen = iov->iov_len;
 947                 unsigned char __user *from = iov->iov_base;
 948
 949                 iov++;
 950
 951                 while (seglen > 0) {
 952                         int copy = 0;
 953                         int max = size_goal;
 954
 955                         skb = tcp_write_queue_tail(sk);
 956                         if (tcp_send_head(sk)) {
 957                                 if (skb->ip_summed == CHECKSUM_NONE)
 958                                         max = mss_now;
 959                                 copy = max - skb->len;
 960                         }
 961
 962                         if (copy <= 0) {
 963 new_segment:
 964                                 /* Allocate new segment. If the interface is SG,
 965                                  * allocate skb fitting to single page.
 966                                  */
 967                                 if (!sk_stream_memory_free(sk))
 968                                         goto wait_for_sndbuf;
 969
 970                                 skb = sk_stream_alloc_skb(sk,
 971                                                           select_size(sk, sg),
 972                                                           sk->sk_allocation);
 973                                 if (!skb)
 974                                         goto wait_for_memory;
 975
 976                                 /*
 977                                  * Check whether we can use HW checksum.
 978                                  */
 979                                 if (sk->sk_route_caps & NETIF_F_ALL_CSUM)
 980                                         skb->ip_summed = CHECKSUM_PARTIAL;
 981
 982                                 skb_entail(sk, skb);
 983                                 copy = size_goal;
 984                                 max = size_goal;
 985                         }
 986
 987                         /* Try to append data to the end of skb. */
 988                         if (copy > seglen)
 989                                 copy = seglen;
 990
 991                         /* Where to copy to? */
 992                         if (skb_tailroom(skb) > 0) {
 993                                 /* We have some space in skb head. Superb! */
 994                                 if (copy > skb_tailroom(skb))
 995                                         copy = skb_tailroom(skb);
 996                                 if ((err = skb_add_data(skb, from, copy)) != 0)
 997                                         goto do_fault;
 998                         } else {
 999                                 int merge = 0;
1000                                 int i = skb_shinfo(skb)->nr_frags;
1001                                 struct page *page = TCP_PAGE(sk);
1002                                 int off = TCP_OFF(sk);
1003
1004                                 if (skb_can_coalesce(skb, i, page, off) &&
1005                                     off != PAGE_SIZE) {
1006                                         /* We can extend the last page
1007                                          * fragment. */
1008                                         merge = 1;
1009                                 } else if (i == MAX_SKB_FRAGS || !sg) {
1010                                         /* Need to add new fragment and cannot
1011                                          * do this because interface is non-SG,
1012                                          * or because all the page slots are
1013                                          * busy. */
1014                                         tcp_mark_push(tp, skb);
1015                                         goto new_segment;
1016                                 } else if (page) {
1017                                         if (off == PAGE_SIZE) {
1018                                                 put_page(page);
1019                                                 TCP_PAGE(sk) = page = NULL;
1020                                                 off = 0;
1021                                         }
1022                                 } else
1023                                         off = 0;
1024
1025                                 if (copy > PAGE_SIZE - off)
1026                                         copy = PAGE_SIZE - off;
1027
1028                                 if (!sk_wmem_schedule(sk, copy))
1029                                         goto wait_for_memory;
1030
1031                                 if (!page) {
1032                                         /* Allocate new cache page. */
1033                                         if (!(page = sk_stream_alloc_page(sk)))
1034                                                 goto wait_for_memory;
1035                                 }
1036
1037                                 /* Time to copy data. We are close to
1038                                  * the end! */
1039                                 err = skb_copy_to_page(sk, from, skb, page,
1040                                                        off, copy);
1041                                 if (err) {
1042                                         /* If this page was new, give it to the
1043                                          * socket so it does not get leaked.
1044                                          */
1045                                         if (!TCP_PAGE(sk)) {
1046                                                 TCP_PAGE(sk) = page;
1047                                                 TCP_OFF(sk) = 0;
1048                                         }
1049                                         goto do_error;
1050                                 }
1051
1052                                 /* Update the skb. */
1053                                 if (merge) {
1054                                         skb_shinfo(skb)->frags[i - 1].size +=
1055                                                                         copy;
1056                                 } else {
1057                                         skb_fill_page_desc(skb, i, page, off, copy);
1058                                         if (TCP_PAGE(sk)) {
1059                                                 get_page(page);
1060                                         } else if (off + copy < PAGE_SIZE) {
1061                                                 get_page(page);
1062                                                 TCP_PAGE(sk) = page;
1063                                         }
1064                                 }
1065
1066                                 TCP_OFF(sk) = off + copy;
1067                         }
1068
1069                         if (!copied)
1070                                 TCP_SKB_CB(skb)->flags &= ~TCPHDR_PSH;
1071
1072                         tp->write_seq += copy;
1073                         TCP_SKB_CB(skb)->end_seq += copy;
1074                         skb_shinfo(skb)->gso_segs = 0;
1075
1076                         from += copy;
1077                         copied += copy;
1078                         if ((seglen -= copy) == 0 && iovlen == 0)
1079                                 goto out;
1080
1081                         if (skb->len < max || (flags & MSG_OOB))
1082                                 continue;
1083
1084                         if (forced_push(tp)) {
1085                                 tcp_mark_push(tp, skb);
1086                                 __tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH);
1087                         } else if (skb == tcp_send_head(sk))
1088                                 tcp_push_one(sk, mss_now);
1089                         continue;
1090
1091 wait_for_sndbuf:
1092                         set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
1093 wait_for_memory:
1094                         if (copied)
1095                                 tcp_push(sk, flags & ~MSG_MORE, mss_now, TCP_NAGLE_PUSH);
1096
1097                         if ((err = sk_stream_wait_memory(sk, &timeo)) != 0)
1098                                 goto do_error;
1099
1100                         mss_now = tcp_send_mss(sk, &size_goal, flags);
1101                 }
1102         }
1103
1104 out:
1105         if (copied)
1106                 tcp_push(sk, flags, mss_now, tp->nonagle);
1107         TCP_CHECK_TIMER(sk);
1108         release_sock(sk);
1109         return copied;
1110
1111 do_fault:
1112         if (!skb->len) {
1113                 tcp_unlink_write_queue(skb, sk);
1114                 /* It is the one place in all of TCP, except connection
1115                  * reset, where we can be unlinking the send_head.
1116                  */
1117                 tcp_check_send_head(sk, skb);
1118                 sk_wmem_free_skb(sk, skb);
1119         }
1120
1121 do_error:
1122         if (copied)
1123                 goto out;
1124 out_err:
1125         err = sk_stream_error(sk, flags, err);
1126         TCP_CHECK_TIMER(sk);
1127         release_sock(sk);
1128         return err;
1129 }
1130 EXPORT_SYMBOL(tcp_sendmsg);
1131
1132 /*
1133  *      Handle reading urgent data. BSD has very simple semantics for
1134  *      this, no blocking and very strange errors 8)
1135  */
1136
1137 static int tcp_recv_urg(struct sock *sk, struct msghdr *msg, int len, int flags)
1138 {
1139         struct tcp_sock *tp = tcp_sk(sk);
1140
1141         /* No URG data to read. */
1142         if (sock_flag(sk, SOCK_URGINLINE) || !tp->urg_data ||
1143             tp->urg_data == TCP_URG_READ)
1144                 return -EINVAL; /* Yes this is right ! */
1145
1146         if (sk->sk_state == TCP_CLOSE && !sock_flag(sk, SOCK_DONE))
1147                 return -ENOTCONN;
1148
1149         if (tp->urg_data & TCP_URG_VALID) {
1150                 int err = 0;
1151                 char c = tp->urg_data;
1152
1153                 if (!(flags & MSG_PEEK))
1154                         tp->urg_data = TCP_URG_READ;
1155
1156                 /* Read urgent data. */
1157                 msg->msg_flags |= MSG_OOB;
1158
1159                 if (len > 0) {
1160                         if (!(flags & MSG_TRUNC))
1161                                 err = memcpy_toiovec(msg->msg_iov, &c, 1);
1162                         len = 1;
1163                 } else
1164                         msg->msg_flags |= MSG_TRUNC;
1165
1166                 return err ? -EFAULT : len;
1167         }
1168
1169         if (sk->sk_state == TCP_CLOSE || (sk->sk_shutdown & RCV_SHUTDOWN))
1170                 return 0;
1171
1172         /* Fixed the recv(..., MSG_OOB) behaviour.  BSD docs and
1173          * the available implementations agree in this case:
1174          * this call should never block, independent of the
1175          * blocking state of the socket.
1176          * Mike <pall@rz.uni-karlsruhe.de>
1177          */
1178         return -EAGAIN;
1179 }
1180
1181 /* Clean up the receive buffer for full frames taken by the user,
1182  * then send an ACK if necessary.  COPIED is the number of bytes
1183  * tcp_recvmsg has given to the user so far, it speeds up the
1184  * calculation of whether or not we must ACK for the sake of
1185  * a window update.
1186  */
1187 void tcp_cleanup_rbuf(struct sock *sk, int copied)
1188 {
1189         struct tcp_sock *tp = tcp_sk(sk);
1190         int time_to_ack = 0;
1191
1192 #if TCP_DEBUG
1193         struct sk_buff *skb = skb_peek(&sk->sk_receive_queue);
1194
1195         WARN(skb && !before(tp->copied_seq, TCP_SKB_CB(skb)->end_seq),
1196              KERN_INFO "cleanup rbuf bug: copied %X seq %X rcvnxt %X\n",
1197              tp->copied_seq, TCP_SKB_CB(skb)->end_seq, tp->rcv_nxt);
1198 #endif
1199
1200         if (inet_csk_ack_scheduled(sk)) {
1201                 const struct inet_connection_sock *icsk = inet_csk(sk);
1202                    /* Delayed ACKs frequently hit locked sockets during bulk
1203                     * receive. */
1204                 if (icsk->icsk_ack.blocked ||
1205                     /* Once-per-two-segments ACK was not sent by tcp_input.c */
1206                     tp->rcv_nxt - tp->rcv_wup > icsk->icsk_ack.rcv_mss ||
1207                     /*
1208                      * If this read emptied read buffer, we send ACK, if
1209                      * connection is not bidirectional, user drained
1210                      * receive buffer and there was a small segment
1211                      * in queue.
1212                      */
1213                     (copied > 0 &&
1214                      ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED2) ||
1215                       ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED) &&
1216                        !icsk->icsk_ack.pingpong)) &&
1217                       !atomic_read(&sk->sk_rmem_alloc)))
1218                         time_to_ack = 1;
1219         }
1220
1221         /* We send an ACK if we can now advertise a non-zero window
1222          * which has been raised "significantly".
1223          *
1224          * Even if window raised up to infinity, do not send window open ACK
1225          * in states, where we will not receive more. It is useless.
1226          */
1227         if (copied > 0 && !time_to_ack && !(sk->sk_shutdown & RCV_SHUTDOWN)) {
1228                 __u32 rcv_window_now = tcp_receive_window(tp);
1229
1230                 /* Optimize, __tcp_select_window() is not cheap. */
1231                 if (2*rcv_window_now <= tp->window_clamp) {
1232                         __u32 new_window = __tcp_select_window(sk);
1233
1234                         /* Send ACK now, if this read freed lots of space
1235                          * in our buffer. Certainly, new_window is new window.
1236                          * We can advertise it now, if it is not less than current one.
1237                          * "Lots" means "at least twice" here.
1238                          */
1239                         if (new_window && new_window >= 2 * rcv_window_now)
1240                                 time_to_ack = 1;
1241                 }
1242         }
1243         if (time_to_ack)
1244                 tcp_send_ack(sk);
1245 }
1246
1247 static void tcp_prequeue_process(struct sock *sk)
1248 {
1249         struct sk_buff *skb;
1250         struct tcp_sock *tp = tcp_sk(sk);
1251
1252         NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPPREQUEUED);
1253
1254         /* RX process wants to run with disabled BHs, though it is not
1255          * necessary */
1256         local_bh_disable();
1257         while ((skb = __skb_dequeue(&tp->ucopy.prequeue)) != NULL)
1258                 sk_backlog_rcv(sk, skb);
1259         local_bh_enable();
1260
1261         /* Clear memory counter. */
1262         tp->ucopy.memory = 0;
1263 }
1264
1265 #ifdef CONFIG_NET_DMA
1266 static void tcp_service_net_dma(struct sock *sk, bool wait)
1267 {
1268         dma_cookie_t done, used;
1269         dma_cookie_t last_issued;
1270         struct tcp_sock *tp = tcp_sk(sk);
1271
1272         if (!tp->ucopy.dma_chan)
1273                 return;
1274
1275         last_issued = tp->ucopy.dma_cookie;
1276         dma_async_memcpy_issue_pending(tp->ucopy.dma_chan);
1277
1278         do {
1279                 if (dma_async_memcpy_complete(tp->ucopy.dma_chan,
1280                                               last_issued, &done,
1281                                               &used) == DMA_SUCCESS) {
1282                         /* Safe to free early-copied skbs now */
1283                         __skb_queue_purge(&sk->sk_async_wait_queue);
1284                         break;
1285                 } else {
1286                         struct sk_buff *skb;
1287                         while ((skb = skb_peek(&sk->sk_async_wait_queue)) &&
1288                                (dma_async_is_complete(skb->dma_cookie, done,
1289                                                       used) == DMA_SUCCESS)) {
1290                                 __skb_dequeue(&sk->sk_async_wait_queue);
1291                                 kfree_skb(skb);
1292                         }
1293                 }
1294         } while (wait);
1295 }
1296 #endif
1297
1298 static inline struct sk_buff *tcp_recv_skb(struct sock *sk, u32 seq, u32 *off)
1299 {
1300         struct sk_buff *skb;
1301         u32 offset;
1302
1303         skb_queue_walk(&sk->sk_receive_queue, skb) {
1304                 offset = seq - TCP_SKB_CB(skb)->seq;
1305                 if (tcp_hdr(skb)->syn)
1306                         offset--;
1307                 if (offset < skb->len || tcp_hdr(skb)->fin) {
1308                         *off = offset;
1309                         return skb;
1310                 }
1311         }
1312         return NULL;
1313 }
1314
1315 /*
1316  * This routine provides an alternative to tcp_recvmsg() for routines
1317  * that would like to handle copying from skbuffs directly in 'sendfile'
1318  * fashion.
1319  * Note:
1320  *      - It is assumed that the socket was locked by the caller.
1321  *      - The routine does not block.
1322  *      - At present, there is no support for reading OOB data
1323  *        or for 'peeking' the socket using this routine
1324  *        (although both would be easy to implement).
1325  */
1326 int tcp_read_sock(struct sock *sk, read_descriptor_t *desc,
1327                   sk_read_actor_t recv_actor)
1328 {
1329         struct sk_buff *skb;
1330         struct tcp_sock *tp = tcp_sk(sk);
1331         u32 seq = tp->copied_seq;
1332         u32 offset;
1333         int copied = 0;
1334
1335         if (sk->sk_state == TCP_LISTEN)
1336                 return -ENOTCONN;
1337         while ((skb = tcp_recv_skb(sk, seq, &offset)) != NULL) {
1338                 if (offset < skb->len) {
1339                         int used;
1340                         size_t len;
1341
1342                         len = skb->len - offset;
1343                         /* Stop reading if we hit a patch of urgent data */
1344                         if (tp->urg_data) {
1345                                 u32 urg_offset = tp->urg_seq - seq;
1346                                 if (urg_offset < len)
1347                                         len = urg_offset;
1348                                 if (!len)
1349                                         break;
1350                         }
1351                         used = recv_actor(desc, skb, offset, len);
1352                         if (used < 0) {
1353                                 if (!copied)
1354                                         copied = used;
1355                                 break;
1356                         } else if (used <= len) {
1357                                 seq += used;
1358                                 copied += used;
1359                                 offset += used;
1360                         }
1361                         /*
1362                          * If recv_actor drops the lock (e.g. TCP splice
1363                          * receive) the skb pointer might be invalid when
1364                          * getting here: tcp_collapse might have deleted it
1365                          * while aggregating skbs from the socket queue.
1366                          */
1367                         skb = tcp_recv_skb(sk, seq-1, &offset);
1368                         if (!skb || (offset+1 != skb->len))
1369                                 break;
1370                 }
1371                 if (tcp_hdr(skb)->fin) {
1372                         sk_eat_skb(sk, skb, 0);
1373                         ++seq;
1374                         break;
1375                 }
1376                 sk_eat_skb(sk, skb, 0);
1377                 if (!desc->count)
1378                         break;
1379                 tp->copied_seq = seq;
1380         }
1381         tp->copied_seq = seq;
1382
1383         tcp_rcv_space_adjust(sk);
1384
1385         /* Clean up data we have read: This will do ACK frames. */
1386         if (copied > 0)
1387                 tcp_cleanup_rbuf(sk, copied);
1388         return copied;
1389 }
1390 EXPORT_SYMBOL(tcp_read_sock);
1391
1392 /*
1393  *      This routine copies from a sock struct into the user buffer.
1394  *
1395  *      Technical note: in 2.3 we work on _locked_ socket, so that
1396  *      tricks with *seq access order and skb->users are not required.
1397  *      Probably, code can be easily improved even more.
1398  */
1399
1400 int tcp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
1401                 size_t len, int nonblock, int flags, int *addr_len)
1402 {
1403         struct tcp_sock *tp = tcp_sk(sk);
1404         int copied = 0;
1405         u32 peek_seq;
1406         u32 *seq;
1407         unsigned long used;
1408         int err;
1409         int target;             /* Read at least this many bytes */
1410         long timeo;
1411         struct task_struct *user_recv = NULL;
1412         int copied_early = 0;
1413         struct sk_buff *skb;
1414         u32 urg_hole = 0;
1415
1416         lock_sock(sk);
1417
1418         TCP_CHECK_TIMER(sk);
1419
1420         err = -ENOTCONN;
1421         if (sk->sk_state == TCP_LISTEN)
1422                 goto out;
1423
1424         timeo = sock_rcvtimeo(sk, nonblock);
1425
1426         /* Urgent data needs to be handled specially. */
1427         if (flags & MSG_OOB)
1428                 goto recv_urg;
1429
1430         seq = &tp->copied_seq;
1431         if (flags & MSG_PEEK) {
1432                 peek_seq = tp->copied_seq;
1433                 seq = &peek_seq;
1434         }
1435
1436         target = sock_rcvlowat(sk, flags & MSG_WAITALL, len);
1437
1438 #ifdef CONFIG_NET_DMA
1439         tp->ucopy.dma_chan = NULL;
1440         preempt_disable();
1441         skb = skb_peek_tail(&sk->sk_receive_queue);
1442         {
1443                 int available = 0;
1444
1445                 if (skb)
1446                         available = TCP_SKB_CB(skb)->seq + skb->len - (*seq);
1447                 if ((available < target) &&
1448                     (len > sysctl_tcp_dma_copybreak) && !(flags & MSG_PEEK) &&
1449                     !sysctl_tcp_low_latency &&
1450                     dma_find_channel(DMA_MEMCPY)) {
1451                         preempt_enable_no_resched();
1452                         tp->ucopy.pinned_list =
1453                                         dma_pin_iovec_pages(msg->msg_iov, len);
1454                 } else {
1455                         preempt_enable_no_resched();
1456                 }
1457         }
1458 #endif
1459
1460         do {
1461                 u32 offset;
1462
1463                 /* Are we at urgent data? Stop if we have read anything or have SIGURG pending. */
1464                 if (tp->urg_data && tp->urg_seq == *seq) {
1465                         if (copied)
1466                                 break;
1467                         if (signal_pending(current)) {
1468                                 copied = timeo ? sock_intr_errno(timeo) : -EAGAIN;
1469                                 break;
1470                         }
1471                 }
1472
1473                 /* Next get a buffer. */
1474
1475                 skb_queue_walk(&sk->sk_receive_queue, skb) {
1476                         /* Now that we have two receive queues this
1477                          * shouldn't happen.
1478                          */
1479                         if (WARN(before(*seq, TCP_SKB_CB(skb)->seq),
1480                              KERN_INFO "recvmsg bug: copied %X "
1481                                        "seq %X rcvnxt %X fl %X\n", *seq,
1482                                        TCP_SKB_CB(skb)->seq, tp->rcv_nxt,
1483                                        flags))
1484                                 break;
1485
1486                         offset = *seq - TCP_SKB_CB(skb)->seq;
1487                         if (tcp_hdr(skb)->syn)
1488                                 offset--;
1489                         if (offset < skb->len)
1490                                 goto found_ok_skb;
1491                         if (tcp_hdr(skb)->fin)
1492                                 goto found_fin_ok;
1493                         WARN(!(flags & MSG_PEEK), KERN_INFO "recvmsg bug 2: "
1494                                         "copied %X seq %X rcvnxt %X fl %X\n",
1495                                         *seq, TCP_SKB_CB(skb)->seq,
1496                                         tp->rcv_nxt, flags);
1497                 }
1498
1499                 /* Well, if we have backlog, try to process it now yet. */
1500
1501                 if (copied >= target && !sk->sk_backlog.tail)
1502                         break;
1503
1504                 if (copied) {
1505                         if (sk->sk_err ||
1506                             sk->sk_state == TCP_CLOSE ||
1507                             (sk->sk_shutdown & RCV_SHUTDOWN) ||
1508                             !timeo ||
1509                             signal_pending(current))
1510                                 break;
1511                 } else {
1512                         if (sock_flag(sk, SOCK_DONE))
1513                                 break;
1514
1515                         if (sk->sk_err) {
1516                                 copied = sock_error(sk);
1517                                 break;
1518                         }
1519
1520                         if (sk->sk_shutdown & RCV_SHUTDOWN)
1521                                 break;
1522
1523                         if (sk->sk_state == TCP_CLOSE) {
1524                                 if (!sock_flag(sk, SOCK_DONE)) {
1525                                         /* This occurs when user tries to read
1526                                          * from never connected socket.
1527                                          */
1528                                         copied = -ENOTCONN;
1529                                         break;
1530                                 }
1531                                 break;
1532                         }
1533
1534                         if (!timeo) {
1535                                 copied = -EAGAIN;
1536                                 break;
1537                         }
1538
1539                         if (signal_pending(current)) {
1540                                 copied = sock_intr_errno(timeo);
1541                                 break;
1542                         }
1543                 }
1544
1545                 tcp_cleanup_rbuf(sk, copied);
1546
1547                 if (!sysctl_tcp_low_latency && tp->ucopy.task == user_recv) {
1548                         /* Install new reader */
1549                         if (!user_recv && !(flags & (MSG_TRUNC | MSG_PEEK))) {
1550                                 user_recv = current;
1551                                 tp->ucopy.task = user_recv;
1552                                 tp->ucopy.iov = msg->msg_iov;
1553                         }
1554
1555                         tp->ucopy.len = len;
1556
1557                         WARN_ON(tp->copied_seq != tp->rcv_nxt &&
1558                                 !(flags & (MSG_PEEK | MSG_TRUNC)));
1559
1560                         /* Ugly... If prequeue is not empty, we have to
1561                          * process it before releasing socket, otherwise
1562                          * order will be broken at second iteration.
1563                          * More elegant solution is required!!!
1564                          *
1565                          * Look: we have the following (pseudo)queues:
1566                          *
1567                          * 1. packets in flight
1568                          * 2. backlog
1569                          * 3. prequeue
1570                          * 4. receive_queue
1571                          *
1572                          * Each queue can be processed only if the next ones
1573                          * are empty. At this point we have empty receive_queue.
1574                          * But prequeue _can_ be not empty after 2nd iteration,
1575                          * when we jumped to start of loop because backlog
1576                          * processing added something to receive_queue.
1577                          * We cannot release_sock(), because backlog contains
1578                          * packets arrived _after_ prequeued ones.
1579                          *
1580                          * Shortly, algorithm is clear --- to process all
1581                          * the queues in order. We could make it more directly,
1582                          * requeueing packets from backlog to prequeue, if
1583                          * is not empty. It is more elegant, but eats cycles,
1584                          * unfortunately.
1585                          */
1586                         if (!skb_queue_empty(&tp->ucopy.prequeue))
1587                                 goto do_prequeue;
1588
1589                         /* __ Set realtime policy in scheduler __ */
1590                 }
1591
1592 #ifdef CONFIG_NET_DMA
1593                 if (tp->ucopy.dma_chan)
1594                         dma_async_memcpy_issue_pending(tp->ucopy.dma_chan);
1595 #endif
1596                 if (copied >= target) {
1597                         /* Do not sleep, just process backlog. */
1598                         release_sock(sk);
1599                         lock_sock(sk);
1600                 } else
1601                         sk_wait_data(sk, &timeo);
1602
1603 #ifdef CONFIG_NET_DMA
1604                 tcp_service_net_dma(sk, false);  /* Don't block */
1605                 tp->ucopy.wakeup = 0;
1606 #endif
1607
1608                 if (user_recv) {
1609                         int chunk;
1610
1611                         /* __ Restore normal policy in scheduler __ */
1612
1613                         if ((chunk = len - tp->ucopy.len) != 0) {
1614                                 NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMBACKLOG, chunk);
1615                                 len -= chunk;
1616                                 copied += chunk;
1617                         }
1618
1619                         if (tp->rcv_nxt == tp->copied_seq &&
1620                             !skb_queue_empty(&tp->ucopy.prequeue)) {
1621 do_prequeue:
1622                                 tcp_prequeue_process(sk);
1623
1624                                 if ((chunk = len - tp->ucopy.len) != 0) {
1625                                         NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
1626                                         len -= chunk;
1627                                         copied += chunk;
1628                                 }
1629                         }
1630                 }
1631                 if ((flags & MSG_PEEK) &&
1632                     (peek_seq - copied - urg_hole != tp->copied_seq)) {
1633                         if (net_ratelimit())
1634                                 printk(KERN_DEBUG "TCP(%s:%d): Application bug, race in MSG_PEEK.\n",
1635                                        current->comm, task_pid_nr(current));
1636                         peek_seq = tp->copied_seq;
1637                 }
1638                 continue;
1639
1640         found_ok_skb:
1641                 /* Ok so how much can we use? */
1642                 used = skb->len - offset;
1643                 if (len < used)
1644                         used = len;
1645
1646                 /* Do we have urgent data here? */
1647                 if (tp->urg_data) {
1648                         u32 urg_offset = tp->urg_seq - *seq;
1649                         if (urg_offset < used) {
1650                                 if (!urg_offset) {
1651                                         if (!sock_flag(sk, SOCK_URGINLINE)) {
1652                                                 ++*seq;
1653                                                 urg_hole++;
1654                                                 offset++;
1655                                                 used--;
1656                                                 if (!used)
1657                                                         goto skip_copy;
1658                                         }
1659                                 } else
1660                                         used = urg_offset;
1661                         }
1662                 }
1663
1664                 if (!(flags & MSG_TRUNC)) {
1665 #ifdef CONFIG_NET_DMA
1666                         if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list)
1667                                 tp->ucopy.dma_chan = dma_find_channel(DMA_MEMCPY);
1668
1669                         if (tp->ucopy.dma_chan) {
1670                                 tp->ucopy.dma_cookie = dma_skb_copy_datagram_iovec(
1671                                         tp->ucopy.dma_chan, skb, offset,
1672                                         msg->msg_iov, used,
1673                                         tp->ucopy.pinned_list);
1674
1675                                 if (tp->ucopy.dma_cookie < 0) {
1676
1677                                         printk(KERN_ALERT "dma_cookie < 0\n");
1678
1679                                         /* Exception. Bailout! */
1680                                         if (!copied)
1681                                                 copied = -EFAULT;
1682                                         break;
1683                                 }
1684
1685                                 dma_async_memcpy_issue_pending(tp->ucopy.dma_chan);
1686
1687                                 if ((offset + used) == skb->len)
1688                                         copied_early = 1;
1689
1690                         } else
1691 #endif
1692                         {
1693                                 err = skb_copy_datagram_iovec(skb, offset,
1694                                                 msg->msg_iov, used);
1695                                 if (err) {
1696                                         /* Exception. Bailout! */
1697                                         if (!copied)
1698                                                 copied = -EFAULT;
1699                                         break;
1700                                 }
1701                         }
1702                 }
1703
1704                 *seq += used;
1705                 copied += used;
1706                 len -= used;
1707
1708                 tcp_rcv_space_adjust(sk);
1709
1710 skip_copy:
1711                 if (tp->urg_data && after(tp->copied_seq, tp->urg_seq)) {
1712                         tp->urg_data = 0;
1713                         tcp_fast_path_check(sk);
1714                 }
1715                 if (used + offset < skb->len)
1716                         continue;
1717
1718                 if (tcp_hdr(skb)->fin)
1719                         goto found_fin_ok;
1720                 if (!(flags & MSG_PEEK)) {
1721                         sk_eat_skb(sk, skb, copied_early);
1722                         copied_early = 0;
1723                 }
1724                 continue;
1725
1726         found_fin_ok:
1727                 /* Process the FIN. */
1728                 ++*seq;
1729                 if (!(flags & MSG_PEEK)) {
1730                         sk_eat_skb(sk, skb, copied_early);
1731                         copied_early = 0;
1732                 }
1733                 break;
1734         } while (len > 0);
1735
1736         if (user_recv) {
1737                 if (!skb_queue_empty(&tp->ucopy.prequeue)) {
1738                         int chunk;
1739
1740                         tp->ucopy.len = copied > 0 ? len : 0;
1741
1742                         tcp_prequeue_process(sk);
1743
1744                         if (copied > 0 && (chunk = len - tp->ucopy.len) != 0) {
1745                                 NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
1746                                 len -= chunk;
1747                                 copied += chunk;
1748                         }
1749                 }
1750
1751                 tp->ucopy.task = NULL;
1752                 tp->ucopy.len = 0;
1753         }
1754
1755 #ifdef CONFIG_NET_DMA
1756         tcp_service_net_dma(sk, true);  /* Wait for queue to drain */
1757         tp->ucopy.dma_chan = NULL;
1758
1759         if (tp->ucopy.pinned_list) {
1760                 dma_unpin_iovec_pages(tp->ucopy.pinned_list);
1761                 tp->ucopy.pinned_list = NULL;
1762         }
1763 #endif
1764
1765         /* According to UNIX98, msg_name/msg_namelen are ignored
1766          * on connected socket. I was just happy when found this 8) --ANK
1767          */
1768
1769         /* Clean up data we have read: This will do ACK frames. */
1770         tcp_cleanup_rbuf(sk, copied);
1771
1772         TCP_CHECK_TIMER(sk);
1773         release_sock(sk);
1774         return copied;
1775
1776 out:
1777         TCP_CHECK_TIMER(sk);
1778         release_sock(sk);
1779         return err;
1780
1781 recv_urg:
1782         err = tcp_recv_urg(sk, msg, len, flags);
1783         goto out;
1784 }
1785 EXPORT_SYMBOL(tcp_recvmsg);
1786
1787 void tcp_set_state(struct sock *sk, int state)
1788 {
1789         int oldstate = sk->sk_state;
1790
1791         switch (state) {
1792         case TCP_ESTABLISHED:
1793                 if (oldstate != TCP_ESTABLISHED)
1794                         TCP_INC_STATS(sock_net(sk), TCP_MIB_CURRESTAB);
1795                 break;
1796
1797         case TCP_CLOSE:
1798                 if (oldstate == TCP_CLOSE_WAIT || oldstate == TCP_ESTABLISHED)
1799                         TCP_INC_STATS(sock_net(sk), TCP_MIB_ESTABRESETS);
1800
1801                 sk->sk_prot->unhash(sk);
1802                 if (inet_csk(sk)->icsk_bind_hash &&
1803                     !(sk->sk_userlocks & SOCK_BINDPORT_LOCK))
1804                         inet_put_port(sk);
1805                 /* fall through */
1806         default:
1807                 if (oldstate == TCP_ESTABLISHED)
1808                         TCP_DEC_STATS(sock_net(sk), TCP_MIB_CURRESTAB);
1809         }
1810
1811         /* Change state AFTER socket is unhashed to avoid closed
1812          * socket sitting in hash tables.
1813          */
1814         sk->sk_state = state;
1815
1816 #ifdef STATE_TRACE
1817         SOCK_DEBUG(sk, "TCP sk=%p, State %s -> %s\n", sk, statename[oldstate], statename[state]);
1818 #endif
1819 }
1820 EXPORT_SYMBOL_GPL(tcp_set_state);
1821
1822 /*
1823  *      State processing on a close. This implements the state shift for
1824  *      sending our FIN frame. Note that we only send a FIN for some
1825  *      states. A shutdown() may have already sent the FIN, or we may be
1826  *      closed.
1827  */
1828
1829 static const unsigned char new_state[16] = {
1830   /* current state:        new state:      action:      */
1831   /* (Invalid)          */ TCP_CLOSE,
1832   /* TCP_ESTABLISHED    */ TCP_FIN_WAIT1 | TCP_ACTION_FIN,
1833   /* TCP_SYN_SENT       */ TCP_CLOSE,
1834   /* TCP_SYN_RECV       */ TCP_FIN_WAIT1 | TCP_ACTION_FIN,
1835   /* TCP_FIN_WAIT1      */ TCP_FIN_WAIT1,
1836   /* TCP_FIN_WAIT2      */ TCP_FIN_WAIT2,
1837   /* TCP_TIME_WAIT      */ TCP_CLOSE,
1838   /* TCP_CLOSE          */ TCP_CLOSE,
1839   /* TCP_CLOSE_WAIT     */ TCP_LAST_ACK  | TCP_ACTION_FIN,
1840   /* TCP_LAST_ACK       */ TCP_LAST_ACK,
1841   /* TCP_LISTEN         */ TCP_CLOSE,
1842   /* TCP_CLOSING        */ TCP_CLOSING,
1843 };
1844
1845 static int tcp_close_state(struct sock *sk)
1846 {
1847         int next = (int)new_state[sk->sk_state];
1848         int ns = next & TCP_STATE_MASK;
1849
1850         tcp_set_state(sk, ns);
1851
1852         return next & TCP_ACTION_FIN;
1853 }
1854
1855 /*
1856  *      Shutdown the sending side of a connection. Much like close except
1857  *      that we don't receive shut down or sock_set_flag(sk, SOCK_DEAD).
1858  */
1859
1860 void tcp_shutdown(struct sock *sk, int how)
1861 {
1862         /*      We need to grab some memory, and put together a FIN,
1863          *      and then put it into the queue to be sent.
1864          *              Tim MacKenzie(tym@dibbler.cs.monash.edu.au) 4 Dec '92.
1865          */
1866         if (!(how & SEND_SHUTDOWN))
1867                 return;
1868
1869         /* If we've already sent a FIN, or it's a closed state, skip this. */
1870         if ((1 << sk->sk_state) &
1871             (TCPF_ESTABLISHED | TCPF_SYN_SENT |
1872              TCPF_SYN_RECV | TCPF_CLOSE_WAIT)) {
1873                 /* Clear out any half completed packets.  FIN if needed. */
1874                 if (tcp_close_state(sk))
1875                         tcp_send_fin(sk);
1876         }
1877 }
1878 EXPORT_SYMBOL(tcp_shutdown);
1879
1880 void tcp_close(struct sock *sk, long timeout)
1881 {
1882         struct sk_buff *skb;
1883         int data_was_unread = 0;
1884         int state;
1885
1886         lock_sock(sk);
1887         sk->sk_shutdown = SHUTDOWN_MASK;
1888
1889         if (sk->sk_state == TCP_LISTEN) {
1890                 tcp_set_state(sk, TCP_CLOSE);
1891
1892                 /* Special case. */
1893                 inet_csk_listen_stop(sk);
1894
1895                 goto adjudge_to_death;
1896         }
1897
1898         /*  We need to flush the recv. buffs.  We do this only on the
1899          *  descriptor close, not protocol-sourced closes, because the
1900          *  reader process may not have drained the data yet!
1901          */
1902         while ((skb = __skb_dequeue(&sk->sk_receive_queue)) != NULL) {
1903                 u32 len = TCP_SKB_CB(skb)->end_seq - TCP_SKB_CB(skb)->seq -
1904                           tcp_hdr(skb)->fin;
1905                 data_was_unread += len;
1906                 __kfree_skb(skb);
1907         }
1908
1909         sk_mem_reclaim(sk);
1910
1911         /* If socket has been already reset (e.g. in tcp_reset()) - kill it. */
1912         if (sk->sk_state == TCP_CLOSE)
1913                 goto adjudge_to_death;
1914
1915         /* As outlined in RFC 2525, section 2.17, we send a RST here because
1916          * data was lost. To witness the awful effects of the old behavior of
1917          * always doing a FIN, run an older 2.1.x kernel or 2.0.x, start a bulk
1918          * GET in an FTP client, suspend the process, wait for the client to
1919          * advertise a zero window, then kill -9 the FTP client, wheee...
1920          * Note: timeout is always zero in such a case.
1921          */
1922         if (data_was_unread) {
1923                 /* Unread data was tossed, zap the connection. */
1924                 NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPABORTONCLOSE);
1925                 tcp_set_state(sk, TCP_CLOSE);
1926                 tcp_send_active_reset(sk, sk->sk_allocation);
1927         } else if (sock_flag(sk, SOCK_LINGER) && !sk->sk_lingertime) {
1928                 /* Check zero linger _after_ checking for unread data. */
1929                 sk->sk_prot->disconnect(sk, 0);
1930                 NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPABORTONDATA);
1931         } else if (tcp_close_state(sk)) {
1932                 /* We FIN if the application ate all the data before
1933                  * zapping the connection.
1934                  */
1935
1936                 /* RED-PEN. Formally speaking, we have broken TCP state
1937                  * machine. State transitions:
1938                  *
1939                  * TCP_ESTABLISHED -> TCP_FIN_WAIT1
1940                  * TCP_SYN_RECV -> TCP_FIN_WAIT1 (forget it, it's impossible)
1941                  * TCP_CLOSE_WAIT -> TCP_LAST_ACK
1942                  *
1943                  * are legal only when FIN has been sent (i.e. in window),
1944                  * rather than queued out of window. Purists blame.
1945                  *
1946                  * F.e. "RFC state" is ESTABLISHED,
1947                  * if Linux state is FIN-WAIT-1, but FIN is still not sent.
1948                  *
1949                  * The visible declinations are that sometimes
1950                  * we enter time-wait state, when it is not required really
1951                  * (harmless), do not send active resets, when they are
1952                  * required by specs (TCP_ESTABLISHED, TCP_CLOSE_WAIT, when
1953                  * they look as CLOSING or LAST_ACK for Linux)
1954                  * Probably, I missed some more holelets.
1955                  *                                              --ANK
1956                  */
1957                 tcp_send_fin(sk);
1958         }
1959
1960         sk_stream_wait_close(sk, timeout);
1961
1962 adjudge_to_death:
1963         state = sk->sk_state;
1964         sock_hold(sk);
1965         sock_orphan(sk);
1966
1967         /* It is the last release_sock in its life. It will remove backlog. */
1968         release_sock(sk);
1969
1970
1971         /* Now socket is owned by kernel and we acquire BH lock
1972            to finish close. No need to check for user refs.
1973          */
1974         local_bh_disable();
1975         bh_lock_sock(sk);
1976         WARN_ON(sock_owned_by_user(sk));
1977
1978         percpu_counter_inc(sk->sk_prot->orphan_count);
1979
1980         /* Have we already been destroyed by a softirq or backlog? */
1981         if (state != TCP_CLOSE && sk->sk_state == TCP_CLOSE)
1982                 goto out;
1983
1984         /*      This is a (useful) BSD violating of the RFC. There is a
1985          *      problem with TCP as specified in that the other end could
1986          *      keep a socket open forever with no application left this end.
1987          *      We use a 3 minute timeout (about the same as BSD) then kill
1988          *      our end. If they send after that then tough - BUT: long enough
1989          *      that we won't make the old 4*rto = almost no time - whoops
1990          *      reset mistake.
1991          *
1992          *      Nope, it was not mistake. It is really desired behaviour
1993          *      f.e. on http servers, when such sockets are useless, but
1994          *      consume significant resources. Let's do it with special
1995          *      linger2 option.                                 --ANK
1996          */
1997
1998         if (sk->sk_state == TCP_FIN_WAIT2) {
1999                 struct tcp_sock *tp = tcp_sk(sk);
2000                 if (tp->linger2 < 0) {
2001                         tcp_set_state(sk, TCP_CLOSE);
2002                         tcp_send_active_reset(sk, GFP_ATOMIC);
2003                         NET_INC_STATS_BH(sock_net(sk),
2004                                         LINUX_MIB_TCPABORTONLINGER);
2005                 } else {
2006                         const int tmo = tcp_fin_time(sk);
2007
2008                         if (tmo > TCP_TIMEWAIT_LEN) {
2009                                 inet_csk_reset_keepalive_timer(sk,
2010                                                 tmo - TCP_TIMEWAIT_LEN);
2011                         } else {
2012                                 tcp_time_wait(sk, TCP_FIN_WAIT2, tmo);
2013                                 goto out;
2014                         }
2015                 }
2016         }
2017         if (sk->sk_state != TCP_CLOSE) {
2018                 sk_mem_reclaim(sk);
2019                 if (tcp_too_many_orphans(sk, 0)) {
2020                         if (net_ratelimit())
2021                                 printk(KERN_INFO "TCP: too many of orphaned "
2022                                        "sockets\n");
2023                         tcp_set_state(sk, TCP_CLOSE);
2024                         tcp_send_active_reset(sk, GFP_ATOMIC);
2025                         NET_INC_STATS_BH(sock_net(sk),
2026                                         LINUX_MIB_TCPABORTONMEMORY);
2027                 }
2028         }
2029
2030         if (sk->sk_state == TCP_CLOSE)
2031                 inet_csk_destroy_sock(sk);
2032         /* Otherwise, socket is reprieved until protocol close. */
2033
2034 out:
2035         bh_unlock_sock(sk);
2036         local_bh_enable();
2037         sock_put(sk);
2038 }
2039 EXPORT_SYMBOL(tcp_close);
2040
2041 /* These states need RST on ABORT according to RFC793 */
2042
2043 static inline int tcp_need_reset(int state)
2044 {
2045         return (1 << state) &
2046                (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT | TCPF_FIN_WAIT1 |
2047                 TCPF_FIN_WAIT2 | TCPF_SYN_RECV);
2048 }
2049
2050 int tcp_disconnect(struct sock *sk, int flags)
2051 {
2052         struct inet_sock *inet = inet_sk(sk);
2053         struct inet_connection_sock *icsk = inet_csk(sk);
2054         struct tcp_sock *tp = tcp_sk(sk);
2055         int err = 0;
2056         int old_state = sk->sk_state;
2057
2058         if (old_state != TCP_CLOSE)
2059                 tcp_set_state(sk, TCP_CLOSE);
2060
2061         /* ABORT function of RFC793 */
2062         if (old_state == TCP_LISTEN) {
2063                 inet_csk_listen_stop(sk);
2064         } else if (tcp_need_reset(old_state) ||
2065                    (tp->snd_nxt != tp->write_seq &&
2066                     (1 << old_state) & (TCPF_CLOSING | TCPF_LAST_ACK))) {
2067                 /* The last check adjusts for discrepancy of Linux wrt. RFC
2068                  * states
2069                  */
2070                 tcp_send_active_reset(sk, gfp_any());
2071                 sk->sk_err = ECONNRESET;
2072         } else if (old_state == TCP_SYN_SENT)
2073                 sk->sk_err = ECONNRESET;
2074
2075         tcp_clear_xmit_timers(sk);
2076         __skb_queue_purge(&sk->sk_receive_queue);
2077         tcp_write_queue_purge(sk);
2078         __skb_queue_purge(&tp->out_of_order_queue);
2079 #ifdef CONFIG_NET_DMA
2080         __skb_queue_purge(&sk->sk_async_wait_queue);
2081 #endif
2082
2083         inet->inet_dport = 0;
2084
2085         if (!(sk->sk_userlocks & SOCK_BINDADDR_LOCK))
2086                 inet_reset_saddr(sk);
2087
2088         sk->sk_shutdown = 0;
2089         sock_reset_flag(sk, SOCK_DONE);
2090         tp->srtt = 0;
2091         if ((tp->write_seq += tp->max_window + 2) == 0)
2092                 tp->write_seq = 1;
2093         icsk->icsk_backoff = 0;
2094         tp->snd_cwnd = 2;
2095         icsk->icsk_probes_out = 0;
2096         tp->packets_out = 0;
2097         tp->snd_ssthresh = TCP_INFINITE_SSTHRESH;
2098         tp->snd_cwnd_cnt = 0;
2099         tp->bytes_acked = 0;
2100         tp->window_clamp = 0;
2101         tcp_set_ca_state(sk, TCP_CA_Open);
2102         tcp_clear_retrans(tp);
2103         inet_csk_delack_init(sk);
2104         tcp_init_send_head(sk);
2105         memset(&tp->rx_opt, 0, sizeof(tp->rx_opt));
2106         __sk_dst_reset(sk);
2107
2108         WARN_ON(inet->inet_num && !icsk->icsk_bind_hash);
2109
2110         sk->sk_error_report(sk);
2111         return err;
2112 }
2113 EXPORT_SYMBOL(tcp_disconnect);
2114
2115 /*
2116  *      Socket option code for TCP.
2117  */
2118 static int do_tcp_setsockopt(struct sock *sk, int level,
2119                 int optname, char __user *optval, unsigned int optlen)
2120 {
2121         struct tcp_sock *tp = tcp_sk(sk);
2122         struct inet_connection_sock *icsk = inet_csk(sk);
2123         int val;
2124         int err = 0;
2125
2126         /* These are data/string values, all the others are ints */
2127         switch (optname) {
2128         case TCP_CONGESTION: {
2129                 char name[TCP_CA_NAME_MAX];
2130
2131                 if (optlen < 1)
2132                         return -EINVAL;
2133
2134                 val = strncpy_from_user(name, optval,
2135                                         min_t(long, TCP_CA_NAME_MAX-1, optlen));
2136                 if (val < 0)
2137                         return -EFAULT;
2138                 name[val] = 0;
2139
2140                 lock_sock(sk);
2141                 err = tcp_set_congestion_control(sk, name);
2142                 release_sock(sk);
2143                 return err;
2144         }
2145         case TCP_COOKIE_TRANSACTIONS: {
2146                 struct tcp_cookie_transactions ctd;
2147                 struct tcp_cookie_values *cvp = NULL;
2148
2149                 if (sizeof(ctd) > optlen)
2150                         return -EINVAL;
2151                 if (copy_from_user(&ctd, optval, sizeof(ctd)))
2152                         return -EFAULT;
2153
2154                 if (ctd.tcpct_used > sizeof(ctd.tcpct_value) ||
2155                     ctd.tcpct_s_data_desired > TCP_MSS_DESIRED)
2156                         return -EINVAL;
2157
2158                 if (ctd.tcpct_cookie_desired == 0) {
2159                         /* default to global value */
2160                 } else if ((0x1 & ctd.tcpct_cookie_desired) ||
2161                            ctd.tcpct_cookie_desired > TCP_COOKIE_MAX ||
2162                            ctd.tcpct_cookie_desired < TCP_COOKIE_MIN) {
2163                         return -EINVAL;
2164                 }
2165
2166                 if (TCP_COOKIE_OUT_NEVER & ctd.tcpct_flags) {
2167                         /* Supercedes all other values */
2168                         lock_sock(sk);
2169                         if (tp->cookie_values != NULL) {
2170                                 kref_put(&tp->cookie_values->kref,
2171                                          tcp_cookie_values_release);
2172                                 tp->cookie_values = NULL;
2173                         }
2174                         tp->rx_opt.cookie_in_always = 0; /* false */
2175                         tp->rx_opt.cookie_out_never = 1; /* true */
2176                         release_sock(sk);
2177                         return err;
2178                 }
2179
2180                 /* Allocate ancillary memory before locking.
2181                  */
2182                 if (ctd.tcpct_used > 0 ||
2183                     (tp->cookie_values == NULL &&
2184                      (sysctl_tcp_cookie_size > 0 ||
2185                       ctd.tcpct_cookie_desired > 0 ||
2186                       ctd.tcpct_s_data_desired > 0))) {
2187                         cvp = kzalloc(sizeof(*cvp) + ctd.tcpct_used,
2188                                       GFP_KERNEL);
2189                         if (cvp == NULL)
2190                                 return -ENOMEM;
2191
2192                         kref_init(&cvp->kref);
2193                 }
2194                 lock_sock(sk);
2195                 tp->rx_opt.cookie_in_always =
2196                         (TCP_COOKIE_IN_ALWAYS & ctd.tcpct_flags);
2197                 tp->rx_opt.cookie_out_never = 0; /* false */
2198
2199                 if (tp->cookie_values != NULL) {
2200                         if (cvp != NULL) {
2201                                 /* Changed values are recorded by a changed
2202                                  * pointer, ensuring the cookie will differ,
2203                                  * without separately hashing each value later.
2204                                  */
2205                                 kref_put(&tp->cookie_values->kref,
2206                                          tcp_cookie_values_release);
2207                         } else {
2208                                 cvp = tp->cookie_values;
2209                         }
2210                 }
2211
2212                 if (cvp != NULL) {
2213                         cvp->cookie_desired = ctd.tcpct_cookie_desired;
2214
2215                         if (ctd.tcpct_used > 0) {
2216                                 memcpy(cvp->s_data_payload, ctd.tcpct_value,
2217                                        ctd.tcpct_used);
2218                                 cvp->s_data_desired = ctd.tcpct_used;
2219                                 cvp->s_data_constant = 1; /* true */
2220                         } else {
2221                                 /* No constant payload data. */
2222                                 cvp->s_data_desired = ctd.tcpct_s_data_desired;
2223                                 cvp->s_data_constant = 0; /* false */
2224                         }
2225
2226                         tp->cookie_values = cvp;
2227                 }
2228                 release_sock(sk);
2229                 return err;
2230         }
2231         default:
2232                 /* fallthru */
2233                 break;
2234         }
2235
2236         if (optlen < sizeof(int))
2237                 return -EINVAL;
2238
2239         if (get_user(val, (int __user *)optval))
2240                 return -EFAULT;
2241
2242         lock_sock(sk);
2243
2244         switch (optname) {
2245         case TCP_MAXSEG:
2246                 /* Values greater than interface MTU won't take effect. However
2247                  * at the point when this call is done we typically don't yet
2248                  * know which interface is going to be used */
2249                 if (val < 8 || val > MAX_TCP_WINDOW) {
2250                         err = -EINVAL;
2251                         break;
2252                 }
2253                 tp->rx_opt.user_mss = val;
2254                 break;
2255
2256         case TCP_NODELAY:
2257                 if (val) {
2258                         /* TCP_NODELAY is weaker than TCP_CORK, so that
2259                          * this option on corked socket is remembered, but
2260                          * it is not activated until cork is cleared.
2261                          *
2262                          * However, when TCP_NODELAY is set we make
2263                          * an explicit push, which overrides even TCP_CORK
2264                          * for currently queued segments.
2265                          */
2266                         tp->nonagle |= TCP_NAGLE_OFF|TCP_NAGLE_PUSH;
2267                         tcp_push_pending_frames(sk);
2268                 } else {
2269                         tp->nonagle &= ~TCP_NAGLE_OFF;
2270                 }
2271                 break;
2272
2273         case TCP_THIN_LINEAR_TIMEOUTS:
2274                 if (val < 0 || val > 1)
2275                         err = -EINVAL;
2276                 else
2277                         tp->thin_lto = val;
2278                 break;
2279
2280         case TCP_THIN_DUPACK:
2281                 if (val < 0 || val > 1)
2282                         err = -EINVAL;
2283                 else
2284                         tp->thin_dupack = val;
2285                 break;
2286
2287         case TCP_CORK:
2288                 /* When set indicates to always queue non-full frames.
2289                  * Later the user clears this option and we transmit
2290                  * any pending partial frames in the queue.  This is
2291                  * meant to be used alongside sendfile() to get properly
2292                  * filled frames when the user (for example) must write
2293                  * out headers with a write() call first and then use
2294                  * sendfile to send out the data parts.
2295                  *
2296                  * TCP_CORK can be set together with TCP_NODELAY and it is
2297                  * stronger than TCP_NODELAY.
2298                  */
2299                 if (val) {
2300                         tp->nonagle |= TCP_NAGLE_CORK;
2301                 } else {
2302                         tp->nonagle &= ~TCP_NAGLE_CORK;
2303                         if (tp->nonagle&TCP_NAGLE_OFF)
2304                                 tp->nonagle |= TCP_NAGLE_PUSH;
2305                         tcp_push_pending_frames(sk);
2306                 }
2307                 break;
2308
2309         case TCP_KEEPIDLE:
2310                 if (val < 1 || val > MAX_TCP_KEEPIDLE)
2311                         err = -EINVAL;
2312                 else {
2313                         tp->keepalive_time = val * HZ;
2314                         if (sock_flag(sk, SOCK_KEEPOPEN) &&
2315                             !((1 << sk->sk_state) &
2316                               (TCPF_CLOSE | TCPF_LISTEN))) {
2317                                 u32 elapsed = keepalive_time_elapsed(tp);
2318                                 if (tp->keepalive_time > elapsed)
2319                                         elapsed = tp->keepalive_time - elapsed;
2320                                 else
2321                                         elapsed = 0;
2322                                 inet_csk_reset_keepalive_timer(sk, elapsed);
2323                         }
2324                 }
2325                 break;
2326         case TCP_KEEPINTVL:
2327                 if (val < 1 || val > MAX_TCP_KEEPINTVL)
2328                         err = -EINVAL;
2329                 else
2330                         tp->keepalive_intvl = val * HZ;
2331                 break;
2332         case TCP_KEEPCNT:
2333                 if (val < 1 || val > MAX_TCP_KEEPCNT)
2334                         err = -EINVAL;
2335                 else
2336                         tp->keepalive_probes = val;
2337                 break;
2338         case TCP_SYNCNT:
2339                 if (val < 1 || val > MAX_TCP_SYNCNT)
2340                         err = -EINVAL;
2341                 else
2342                         icsk->icsk_syn_retries = val;
2343                 break;
2344
2345         case TCP_LINGER2:
2346                 if (val < 0)
2347                         tp->linger2 = -1;
2348                 else if (val > sysctl_tcp_fin_timeout / HZ)
2349                         tp->linger2 = 0;
2350                 else
2351                         tp->linger2 = val * HZ;
2352                 break;
2353
2354         case TCP_DEFER_ACCEPT:
2355                 /* Translate value in seconds to number of retransmits */
2356                 icsk->icsk_accept_queue.rskq_defer_accept =
2357                         secs_to_retrans(val, TCP_TIMEOUT_INIT / HZ,
2358                                         TCP_RTO_MAX / HZ);
2359                 break;
2360
2361         case TCP_WINDOW_CLAMP:
2362                 if (!val) {
2363                         if (sk->sk_state != TCP_CLOSE) {
2364                                 err = -EINVAL;
2365                                 break;
2366                         }
2367                         tp->window_clamp = 0;
2368                 } else
2369                         tp->window_clamp = val < SOCK_MIN_RCVBUF / 2 ?
2370                                                 SOCK_MIN_RCVBUF / 2 : val;
2371                 break;
2372
2373         case TCP_QUICKACK:
2374                 if (!val) {
2375                         icsk->icsk_ack.pingpong = 1;
2376                 } else {
2377                         icsk->icsk_ack.pingpong = 0;
2378                         if ((1 << sk->sk_state) &
2379                             (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT) &&
2380                             inet_csk_ack_scheduled(sk)) {
2381                                 icsk->icsk_ack.pending |= ICSK_ACK_PUSHED;
2382                                 tcp_cleanup_rbuf(sk, 1);
2383                                 if (!(val & 1))
2384                                         icsk->icsk_ack.pingpong = 1;
2385                         }
2386                 }
2387                 break;
2388
2389 #ifdef CONFIG_TCP_MD5SIG
2390         case TCP_MD5SIG:
2391                 /* Read the IP->Key mappings from userspace */
2392                 err = tp->af_specific->md5_parse(sk, optval, optlen);
2393                 break;
2394 #endif
2395
2396         default:
2397                 err = -ENOPROTOOPT;
2398                 break;
2399         }
2400
2401         release_sock(sk);
2402         return err;
2403 }
2404
2405 int tcp_setsockopt(struct sock *sk, int level, int optname, char __user *optval,
2406                    unsigned int optlen)
2407 {
2408         struct inet_connection_sock *icsk = inet_csk(sk);
2409
2410         if (level != SOL_TCP)
2411                 return icsk->icsk_af_ops->setsockopt(sk, level, optname,
2412                                                      optval, optlen);
2413         return do_tcp_setsockopt(sk, level, optname, optval, optlen);
2414 }
2415 EXPORT_SYMBOL(tcp_setsockopt);
2416
2417 #ifdef CONFIG_COMPAT
2418 int compat_tcp_setsockopt(struct sock *sk, int level, int optname,
2419                           char __user *optval, unsigned int optlen)
2420 {
2421         if (level != SOL_TCP)
2422                 return inet_csk_compat_setsockopt(sk, level, optname,
2423                                                   optval, optlen);
2424         return do_tcp_setsockopt(sk, level, optname, optval, optlen);
2425 }
2426 EXPORT_SYMBOL(compat_tcp_setsockopt);
2427 #endif
2428
2429 /* Return information about state of tcp endpoint in API format. */
2430 void tcp_get_info(struct sock *sk, struct tcp_info *info)
2431 {
2432         struct tcp_sock *tp = tcp_sk(sk);
2433         const struct inet_connection_sock *icsk = inet_csk(sk);
2434         u32 now = tcp_time_stamp;
2435
2436         memset(info, 0, sizeof(*info));
2437
2438         info->tcpi_state = sk->sk_state;
2439         info->tcpi_ca_state = icsk->icsk_ca_state;
2440         info->tcpi_retransmits = icsk->icsk_retransmits;
2441         info->tcpi_probes = icsk->icsk_probes_out;
2442         info->tcpi_backoff = icsk->icsk_backoff;
2443
2444         if (tp->rx_opt.tstamp_ok)
2445                 info->tcpi_options |= TCPI_OPT_TIMESTAMPS;
2446         if (tcp_is_sack(tp))
2447                 info->tcpi_options |= TCPI_OPT_SACK;
2448         if (tp->rx_opt.wscale_ok) {
2449                 info->tcpi_options |= TCPI_OPT_WSCALE;
2450                 info->tcpi_snd_wscale = tp->rx_opt.snd_wscale;
2451                 info->tcpi_rcv_wscale = tp->rx_opt.rcv_wscale;
2452         }
2453
2454         if (tp->ecn_flags&TCP_ECN_OK)
2455                 info->tcpi_options |= TCPI_OPT_ECN;
2456
2457         info->tcpi_rto = jiffies_to_usecs(icsk->icsk_rto);
2458         info->tcpi_ato = jiffies_to_usecs(icsk->icsk_ack.ato);
2459         info->tcpi_snd_mss = tp->mss_cache;
2460         info->tcpi_rcv_mss = icsk->icsk_ack.rcv_mss;
2461
2462         if (sk->sk_state == TCP_LISTEN) {
2463                 info->tcpi_unacked = sk->sk_ack_backlog;
2464                 info->tcpi_sacked = sk->sk_max_ack_backlog;
2465         } else {
2466                 info->tcpi_unacked = tp->packets_out;
2467                 info->tcpi_sacked = tp->sacked_out;
2468         }
2469         info->tcpi_lost = tp->lost_out;
2470         info->tcpi_retrans = tp->retrans_out;
2471         info->tcpi_fackets = tp->fackets_out;
2472
2473         info->tcpi_last_data_sent = jiffies_to_msecs(now - tp->lsndtime);
2474         info->tcpi_last_data_recv = jiffies_to_msecs(now - icsk->icsk_ack.lrcvtime);
2475         info->tcpi_last_ack_recv = jiffies_to_msecs(now - tp->rcv_tstamp);
2476
2477         info->tcpi_pmtu = icsk->icsk_pmtu_cookie;
2478         info->tcpi_rcv_ssthresh = tp->rcv_ssthresh;
2479         info->tcpi_rtt = jiffies_to_usecs(tp->srtt)>>3;
2480         info->tcpi_rttvar = jiffies_to_usecs(tp->mdev)>>2;
2481         info->tcpi_snd_ssthresh = tp->snd_ssthresh;
2482         info->tcpi_snd_cwnd = tp->snd_cwnd;
2483         info->tcpi_advmss = tp->advmss;
2484         info->tcpi_reordering = tp->reordering;
2485
2486         info->tcpi_rcv_rtt = jiffies_to_usecs(tp->rcv_rtt_est.rtt)>>3;
2487         info->tcpi_rcv_space = tp->rcvq_space.space;
2488
2489         info->tcpi_total_retrans = tp->total_retrans;
2490 }
2491 EXPORT_SYMBOL_GPL(tcp_get_info);
2492
2493 static int do_tcp_getsockopt(struct sock *sk, int level,
2494                 int optname, char __user *optval, int __user *optlen)
2495 {
2496         struct inet_connection_sock *icsk = inet_csk(sk);
2497         struct tcp_sock *tp = tcp_sk(sk);
2498         int val, len;
2499
2500         if (get_user(len, optlen))
2501                 return -EFAULT;
2502
2503         len = min_t(unsigned int, len, sizeof(int));
2504
2505         if (len < 0)
2506                 return -EINVAL;
2507
2508         switch (optname) {
2509         case TCP_MAXSEG:
2510                 val = tp->mss_cache;
2511                 if (!val && ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN)))
2512                         val = tp->rx_opt.user_mss;
2513                 break;
2514         case TCP_NODELAY:
2515                 val = !!(tp->nonagle&TCP_NAGLE_OFF);
2516                 break;
2517         case TCP_CORK:
2518                 val = !!(tp->nonagle&TCP_NAGLE_CORK);
2519                 break;
2520         case TCP_KEEPIDLE:
2521                 val = keepalive_time_when(tp) / HZ;
2522                 break;
2523         case TCP_KEEPINTVL:
2524                 val = keepalive_intvl_when(tp) / HZ;
2525                 break;
2526         case TCP_KEEPCNT:
2527                 val = keepalive_probes(tp);
2528                 break;
2529         case TCP_SYNCNT:
2530                 val = icsk->icsk_syn_retries ? : sysctl_tcp_syn_retries;
2531                 break;
2532         case TCP_LINGER2:
2533                 val = tp->linger2;
2534                 if (val >= 0)
2535                         val = (val ? : sysctl_tcp_fin_timeout) / HZ;
2536                 break;
2537         case TCP_DEFER_ACCEPT:
2538                 val = retrans_to_secs(icsk->icsk_accept_queue.rskq_defer_accept,
2539                                       TCP_TIMEOUT_INIT / HZ, TCP_RTO_MAX / HZ);
2540                 break;
2541         case TCP_WINDOW_CLAMP:
2542                 val = tp->window_clamp;
2543                 break;
2544         case TCP_INFO: {
2545                 struct tcp_info info;
2546
2547                 if (get_user(len, optlen))
2548                         return -EFAULT;
2549
2550                 tcp_get_info(sk, &info);
2551
2552                 len = min_t(unsigned int, len, sizeof(info));
2553                 if (put_user(len, optlen))
2554                         return -EFAULT;
2555                 if (copy_to_user(optval, &info, len))
2556                         return -EFAULT;
2557                 return 0;
2558         }
2559         case TCP_QUICKACK:
2560                 val = !icsk->icsk_ack.pingpong;
2561                 break;
2562
2563         case TCP_CONGESTION:
2564                 if (get_user(len, optlen))
2565                         return -EFAULT;
2566                 len = min_t(unsigned int, len, TCP_CA_NAME_MAX);
2567                 if (put_user(len, optlen))
2568                         return -EFAULT;
2569                 if (copy_to_user(optval, icsk->icsk_ca_ops->name, len))
2570                         return -EFAULT;
2571                 return 0;
2572
2573         case TCP_COOKIE_TRANSACTIONS: {
2574                 struct tcp_cookie_transactions ctd;
2575                 struct tcp_cookie_values *cvp = tp->cookie_values;
2576
2577                 if (get_user(len, optlen))
2578                         return -EFAULT;
2579                 if (len < sizeof(ctd))
2580                         return -EINVAL;
2581
2582                 memset(&ctd, 0, sizeof(ctd));
2583                 ctd.tcpct_flags = (tp->rx_opt.cookie_in_always ?
2584                                    TCP_COOKIE_IN_ALWAYS : 0)
2585                                 | (tp->rx_opt.cookie_out_never ?
2586                                    TCP_COOKIE_OUT_NEVER : 0);
2587
2588                 if (cvp != NULL) {
2589                         ctd.tcpct_flags |= (cvp->s_data_in ?
2590                                             TCP_S_DATA_IN : 0)
2591                                          | (cvp->s_data_out ?
2592                                             TCP_S_DATA_OUT : 0);
2593
2594                         ctd.tcpct_cookie_desired = cvp->cookie_desired;
2595                         ctd.tcpct_s_data_desired = cvp->s_data_desired;
2596
2597                         memcpy(&ctd.tcpct_value[0], &cvp->cookie_pair[0],
2598                                cvp->cookie_pair_size);
2599                         ctd.tcpct_used = cvp->cookie_pair_size;
2600                 }
2601
2602                 if (put_user(sizeof(ctd), optlen))
2603                         return -EFAULT;
2604                 if (copy_to_user(optval, &ctd, sizeof(ctd)))
2605                         return -EFAULT;
2606                 return 0;
2607         }
2608         case TCP_THIN_LINEAR_TIMEOUTS:
2609                 val = tp->thin_lto;
2610                 break;
2611         case TCP_THIN_DUPACK:
2612                 val = tp->thin_dupack;
2613                 break;
2614         default:
2615                 return -ENOPROTOOPT;
2616         }
2617
2618         if (put_user(len, optlen))
2619                 return -EFAULT;
2620         if (copy_to_user(optval, &val, len))
2621                 return -EFAULT;
2622         return 0;
2623 }
2624
2625 int tcp_getsockopt(struct sock *sk, int level, int optname, char __user *optval,
2626                    int __user *optlen)
2627 {
2628         struct inet_connection_sock *icsk = inet_csk(sk);
2629
2630         if (level != SOL_TCP)
2631                 return icsk->icsk_af_ops->getsockopt(sk, level, optname,
2632                                                      optval, optlen);
2633         return do_tcp_getsockopt(sk, level, optname, optval, optlen);
2634 }
2635 EXPORT_SYMBOL(tcp_getsockopt);
2636
2637 #ifdef CONFIG_COMPAT
2638 int compat_tcp_getsockopt(struct sock *sk, int level, int optname,
2639                           char __user *optval, int __user *optlen)
2640 {
2641         if (level != SOL_TCP)
2642                 return inet_csk_compat_getsockopt(sk, level, optname,
2643                                                   optval, optlen);
2644         return do_tcp_getsockopt(sk, level, optname, optval, optlen);
2645 }
2646 EXPORT_SYMBOL(compat_tcp_getsockopt);
2647 #endif
2648
2649 struct sk_buff *tcp_tso_segment(struct sk_buff *skb, int features)
2650 {
2651         struct sk_buff *segs = ERR_PTR(-EINVAL);
2652         struct tcphdr *th;
2653         unsigned thlen;
2654         unsigned int seq;
2655         __be32 delta;
2656         unsigned int oldlen;
2657         unsigned int mss;
2658
2659         if (!pskb_may_pull(skb, sizeof(*th)))
2660                 goto out;
2661
2662         th = tcp_hdr(skb);
2663         thlen = th->doff * 4;
2664         if (thlen < sizeof(*th))
2665                 goto out;
2666
2667         if (!pskb_may_pull(skb, thlen))
2668                 goto out;
2669
2670         oldlen = (u16)~skb->len;
2671         __skb_pull(skb, thlen);
2672
2673         mss = skb_shinfo(skb)->gso_size;
2674         if (unlikely(skb->len <= mss))
2675                 goto out;
2676
2677         if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) {
2678                 /* Packet is from an untrusted source, reset gso_segs. */
2679                 int type = skb_shinfo(skb)->gso_type;
2680
2681                 if (unlikely(type &
2682                              ~(SKB_GSO_TCPV4 |
2683                                SKB_GSO_DODGY |
2684                                SKB_GSO_TCP_ECN |
2685                                SKB_GSO_TCPV6 |
2686                                0) ||
2687                              !(type & (SKB_GSO_TCPV4 | SKB_GSO_TCPV6))))
2688                         goto out;
2689
2690                 skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss);
2691
2692                 segs = NULL;
2693                 goto out;
2694         }
2695
2696         segs = skb_segment(skb, features);
2697         if (IS_ERR(segs))
2698                 goto out;
2699
2700         delta = htonl(oldlen + (thlen + mss));
2701
2702         skb = segs;
2703         th = tcp_hdr(skb);
2704         seq = ntohl(th->seq);
2705
2706         do {
2707                 th->fin = th->psh = 0;
2708
2709                 th->check = ~csum_fold((__force __wsum)((__force u32)th->check +
2710                                        (__force u32)delta));
2711                 if (skb->ip_summed != CHECKSUM_PARTIAL)
2712                         th->check =
2713                              csum_fold(csum_partial(skb_transport_header(skb),
2714                                                     thlen, skb->csum));
2715
2716                 seq += mss;
2717                 skb = skb->next;
2718                 th = tcp_hdr(skb);
2719
2720                 th->seq = htonl(seq);
2721                 th->cwr = 0;
2722         } while (skb->next);
2723
2724         delta = htonl(oldlen + (skb->tail - skb->transport_header) +
2725                       skb->data_len);
2726         th->check = ~csum_fold((__force __wsum)((__force u32)th->check +
2727                                 (__force u32)delta));
2728         if (skb->ip_summed != CHECKSUM_PARTIAL)
2729                 th->check = csum_fold(csum_partial(skb_transport_header(skb),
2730                                                    thlen, skb->csum));
2731
2732 out:
2733         return segs;
2734 }
2735 EXPORT_SYMBOL(tcp_tso_segment);
2736
2737 struct sk_buff **tcp_gro_receive(struct sk_buff **head, struct sk_buff *skb)
2738 {
2739         struct sk_buff **pp = NULL;
2740         struct sk_buff *p;
2741         struct tcphdr *th;
2742         struct tcphdr *th2;
2743         unsigned int len;
2744         unsigned int thlen;
2745         __be32 flags;
2746         unsigned int mss = 1;
2747         unsigned int hlen;
2748         unsigned int off;
2749         int flush = 1;
2750         int i;
2751
2752         off = skb_gro_offset(skb);
2753         hlen = off + sizeof(*th);
2754         th = skb_gro_header_fast(skb, off);
2755         if (skb_gro_header_hard(skb, hlen)) {
2756                 th = skb_gro_header_slow(skb, hlen, off);
2757                 if (unlikely(!th))
2758                         goto out;
2759         }
2760
2761         thlen = th->doff * 4;
2762         if (thlen < sizeof(*th))
2763                 goto out;
2764
2765         hlen = off + thlen;
2766         if (skb_gro_header_hard(skb, hlen)) {
2767                 th = skb_gro_header_slow(skb, hlen, off);
2768                 if (unlikely(!th))
2769                         goto out;
2770         }
2771
2772         skb_gro_pull(skb, thlen);
2773
2774         len = skb_gro_len(skb);
2775         flags = tcp_flag_word(th);
2776
2777         for (; (p = *head); head = &p->next) {
2778                 if (!NAPI_GRO_CB(p)->same_flow)
2779                         continue;
2780
2781                 th2 = tcp_hdr(p);
2782
2783                 if (*(u32 *)&th->source ^ *(u32 *)&th2->source) {
2784                         NAPI_GRO_CB(p)->same_flow = 0;
2785                         continue;
2786                 }
2787
2788                 goto found;
2789         }
2790
2791         goto out_check_final;
2792
2793 found:
2794         flush = NAPI_GRO_CB(p)->flush;
2795         flush |= (__force int)(flags & TCP_FLAG_CWR);
2796         flush |= (__force int)((flags ^ tcp_flag_word(th2)) &
2797                   ~(TCP_FLAG_CWR | TCP_FLAG_FIN | TCP_FLAG_PSH));
2798         flush |= (__force int)(th->ack_seq ^ th2->ack_seq);
2799         for (i = sizeof(*th); i < thlen; i += 4)
2800                 flush |= *(u32 *)((u8 *)th + i) ^
2801                          *(u32 *)((u8 *)th2 + i);
2802
2803         mss = skb_shinfo(p)->gso_size;
2804
2805         flush |= (len - 1) >= mss;
2806         flush |= (ntohl(th2->seq) + skb_gro_len(p)) ^ ntohl(th->seq);
2807
2808         if (flush || skb_gro_receive(head, skb)) {
2809                 mss = 1;
2810                 goto out_check_final;
2811         }
2812
2813         p = *head;
2814         th2 = tcp_hdr(p);
2815         tcp_flag_word(th2) |= flags & (TCP_FLAG_FIN | TCP_FLAG_PSH);
2816
2817 out_check_final:
2818         flush = len < mss;
2819         flush |= (__force int)(flags & (TCP_FLAG_URG | TCP_FLAG_PSH |
2820                                         TCP_FLAG_RST | TCP_FLAG_SYN |
2821                                         TCP_FLAG_FIN));
2822
2823         if (p && (!NAPI_GRO_CB(skb)->same_flow || flush))
2824                 pp = head;
2825
2826 out:
2827         NAPI_GRO_CB(skb)->flush |= flush;
2828
2829         return pp;
2830 }
2831 EXPORT_SYMBOL(tcp_gro_receive);
2832
2833 int tcp_gro_complete(struct sk_buff *skb)
2834 {
2835         struct tcphdr *th = tcp_hdr(skb);
2836
2837         skb->csum_start = skb_transport_header(skb) - skb->head;
2838         skb->csum_offset = offsetof(struct tcphdr, check);
2839         skb->ip_summed = CHECKSUM_PARTIAL;
2840
2841         skb_shinfo(skb)->gso_segs = NAPI_GRO_CB(skb)->count;
2842
2843         if (th->cwr)
2844                 skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
2845
2846         return 0;
2847 }
2848 EXPORT_SYMBOL(tcp_gro_complete);
2849
2850 #ifdef CONFIG_TCP_MD5SIG
2851 static unsigned long tcp_md5sig_users;
2852 static struct tcp_md5sig_pool * __percpu *tcp_md5sig_pool;
2853 static DEFINE_SPINLOCK(tcp_md5sig_pool_lock);
2854
2855 static void __tcp_free_md5sig_pool(struct tcp_md5sig_pool * __percpu *pool)
2856 {
2857         int cpu;
2858         for_each_possible_cpu(cpu) {
2859                 struct tcp_md5sig_pool *p = *per_cpu_ptr(pool, cpu);
2860                 if (p) {
2861                         if (p->md5_desc.tfm)
2862                                 crypto_free_hash(p->md5_desc.tfm);
2863                         kfree(p);
2864                 }
2865         }
2866         free_percpu(pool);
2867 }
2868
2869 void tcp_free_md5sig_pool(void)
2870 {
2871         struct tcp_md5sig_pool * __percpu *pool = NULL;
2872
2873         spin_lock_bh(&tcp_md5sig_pool_lock);
2874         if (--tcp_md5sig_users == 0) {
2875                 pool = tcp_md5sig_pool;
2876                 tcp_md5sig_pool = NULL;
2877         }
2878         spin_unlock_bh(&tcp_md5sig_pool_lock);
2879         if (pool)
2880                 __tcp_free_md5sig_pool(pool);
2881 }
2882 EXPORT_SYMBOL(tcp_free_md5sig_pool);
2883
2884 static struct tcp_md5sig_pool * __percpu *
2885 __tcp_alloc_md5sig_pool(struct sock *sk)
2886 {
2887         int cpu;
2888         struct tcp_md5sig_pool * __percpu *pool;
2889
2890         pool = alloc_percpu(struct tcp_md5sig_pool *);
2891         if (!pool)
2892                 return NULL;
2893
2894         for_each_possible_cpu(cpu) {
2895                 struct tcp_md5sig_pool *p;
2896                 struct crypto_hash *hash;
2897
2898                 p = kzalloc(sizeof(*p), sk->sk_allocation);
2899                 if (!p)
2900                         goto out_free;
2901                 *per_cpu_ptr(pool, cpu) = p;
2902
2903                 hash = crypto_alloc_hash("md5", 0, CRYPTO_ALG_ASYNC);
2904                 if (!hash || IS_ERR(hash))
2905                         goto out_free;
2906
2907                 p->md5_desc.tfm = hash;
2908         }
2909         return pool;
2910 out_free:
2911         __tcp_free_md5sig_pool(pool);
2912         return NULL;
2913 }
2914
2915 struct tcp_md5sig_pool * __percpu *tcp_alloc_md5sig_pool(struct sock *sk)
2916 {
2917         struct tcp_md5sig_pool * __percpu *pool;
2918         int alloc = 0;
2919
2920 retry:
2921         spin_lock_bh(&tcp_md5sig_pool_lock);
2922         pool = tcp_md5sig_pool;
2923         if (tcp_md5sig_users++ == 0) {
2924                 alloc = 1;
2925                 spin_unlock_bh(&tcp_md5sig_pool_lock);
2926         } else if (!pool) {
2927                 tcp_md5sig_users--;
2928                 spin_unlock_bh(&tcp_md5sig_pool_lock);
2929                 cpu_relax();
2930                 goto retry;
2931         } else
2932                 spin_unlock_bh(&tcp_md5sig_pool_lock);
2933
2934         if (alloc) {
2935                 /* we cannot hold spinlock here because this may sleep. */
2936                 struct tcp_md5sig_pool * __percpu *p;
2937
2938                 p = __tcp_alloc_md5sig_pool(sk);
2939                 spin_lock_bh(&tcp_md5sig_pool_lock);
2940                 if (!p) {
2941                         tcp_md5sig_users--;
2942                         spin_unlock_bh(&tcp_md5sig_pool_lock);
2943                         return NULL;
2944                 }
2945                 pool = tcp_md5sig_pool;
2946                 if (pool) {
2947                         /* oops, it has already been assigned. */
2948                         spin_unlock_bh(&tcp_md5sig_pool_lock);
2949                         __tcp_free_md5sig_pool(p);
2950                 } else {
2951                         tcp_md5sig_pool = pool = p;
2952                         spin_unlock_bh(&tcp_md5sig_pool_lock);
2953                 }
2954         }
2955         return pool;
2956 }
2957 EXPORT_SYMBOL(tcp_alloc_md5sig_pool);
2958
2959
2960 /**
2961  *      tcp_get_md5sig_pool - get md5sig_pool for this user
2962  *
2963  *      We use percpu structure, so if we succeed, we exit with preemption
2964  *      and BH disabled, to make sure another thread or softirq handling
2965  *      wont try to get same context.
2966  */
2967 struct tcp_md5sig_pool *tcp_get_md5sig_pool(void)
2968 {
2969         struct tcp_md5sig_pool * __percpu *p;
2970
2971         local_bh_disable();
2972
2973         spin_lock(&tcp_md5sig_pool_lock);
2974         p = tcp_md5sig_pool;
2975         if (p)
2976                 tcp_md5sig_users++;
2977         spin_unlock(&tcp_md5sig_pool_lock);
2978
2979         if (p)
2980                 return *this_cpu_ptr(p);
2981
2982         local_bh_enable();
2983         return NULL;
2984 }
2985 EXPORT_SYMBOL(tcp_get_md5sig_pool);
2986
2987 void tcp_put_md5sig_pool(void)
2988 {
2989         local_bh_enable();
2990         tcp_free_md5sig_pool();
2991 }
2992 EXPORT_SYMBOL(tcp_put_md5sig_pool);
2993
2994 int tcp_md5_hash_header(struct tcp_md5sig_pool *hp,
2995                         struct tcphdr *th)
2996 {
2997         struct scatterlist sg;
2998         int err;
2999
3000         __sum16 old_checksum = th->check;
3001         th->check = 0;
3002         /* options aren't included in the hash */
3003         sg_init_one(&sg, th, sizeof(struct tcphdr));
3004         err = crypto_hash_update(&hp->md5_desc, &sg, sizeof(struct tcphdr));
3005         th->check = old_checksum;
3006         return err;
3007 }
3008 EXPORT_SYMBOL(tcp_md5_hash_header);
3009
3010 int tcp_md5_hash_skb_data(struct tcp_md5sig_pool *hp,
3011                           struct sk_buff *skb, unsigned header_len)
3012 {
3013         struct scatterlist sg;
3014         const struct tcphdr *tp = tcp_hdr(skb);
3015         struct hash_desc *desc = &hp->md5_desc;
3016         unsigned i;
3017         const unsigned head_data_len = skb_headlen(skb) > header_len ?
3018                                        skb_headlen(skb) - header_len : 0;
3019         const struct skb_shared_info *shi = skb_shinfo(skb);
3020         struct sk_buff *frag_iter;
3021
3022         sg_init_table(&sg, 1);
3023
3024         sg_set_buf(&sg, ((u8 *) tp) + header_len, head_data_len);
3025         if (crypto_hash_update(desc, &sg, head_data_len))
3026                 return 1;
3027
3028         for (i = 0; i < shi->nr_frags; ++i) {
3029                 const struct skb_frag_struct *f = &shi->frags[i];
3030                 sg_set_page(&sg, f->page, f->size, f->page_offset);
3031                 if (crypto_hash_update(desc, &sg, f->size))
3032                         return 1;
3033         }
3034
3035         skb_walk_frags(skb, frag_iter)
3036                 if (tcp_md5_hash_skb_data(hp, frag_iter, 0))
3037                         return 1;
3038
3039         return 0;
3040 }
3041 EXPORT_SYMBOL(tcp_md5_hash_skb_data);
3042
3043 int tcp_md5_hash_key(struct tcp_md5sig_pool *hp, struct tcp_md5sig_key *key)
3044 {
3045         struct scatterlist sg;
3046
3047         sg_init_one(&sg, key->key, key->keylen);
3048         return crypto_hash_update(&hp->md5_desc, &sg, key->keylen);
3049 }
3050 EXPORT_SYMBOL(tcp_md5_hash_key);
3051
3052 #endif
3053
3054 /**
3055  * Each Responder maintains up to two secret values concurrently for
3056  * efficient secret rollover.  Each secret value has 4 states:
3057  *
3058  * Generating.  (tcp_secret_generating != tcp_secret_primary)
3059  *    Generates new Responder-Cookies, but not yet used for primary
3060  *    verification.  This is a short-term state, typically lasting only
3061  *    one round trip time (RTT).
3062  *
3063  * Primary.  (tcp_secret_generating == tcp_secret_primary)
3064  *    Used both for generation and primary verification.
3065  *
3066  * Retiring.  (tcp_secret_retiring != tcp_secret_secondary)
3067  *    Used for verification, until the first failure that can be
3068  *    verified by the newer Generating secret.  At that time, this
3069  *    cookie's state is changed to Secondary, and the Generating
3070  *    cookie's state is changed to Primary.  This is a short-term state,
3071  *    typically lasting only one round trip time (RTT).
3072  *
3073  * Secondary.  (tcp_secret_retiring == tcp_secret_secondary)
3074  *    Used for secondary verification, after primary verification
3075  *    failures.  This state lasts no more than twice the Maximum Segment
3076  *    Lifetime (2MSL).  Then, the secret is discarded.
3077  */
3078 struct tcp_cookie_secret {
3079         /* The secret is divided into two parts.  The digest part is the
3080          * equivalent of previously hashing a secret and saving the state,
3081          * and serves as an initialization vector (IV).  The message part
3082          * serves as the trailing secret.
3083          */
3084         u32                             secrets[COOKIE_WORKSPACE_WORDS];
3085         unsigned long                   expires;
3086 };
3087
3088 #define TCP_SECRET_1MSL (HZ * TCP_PAWS_MSL)
3089 #define TCP_SECRET_2MSL (HZ * TCP_PAWS_MSL * 2)
3090 #define TCP_SECRET_LIFE (HZ * 600)
3091
3092 static struct tcp_cookie_secret tcp_secret_one;
3093 static struct tcp_cookie_secret tcp_secret_two;
3094
3095 /* Essentially a circular list, without dynamic allocation. */
3096 static struct tcp_cookie_secret *tcp_secret_generating;
3097 static struct tcp_cookie_secret *tcp_secret_primary;
3098 static struct tcp_cookie_secret *tcp_secret_retiring;
3099 static struct tcp_cookie_secret *tcp_secret_secondary;
3100
3101 static DEFINE_SPINLOCK(tcp_secret_locker);
3102
3103 /* Select a pseudo-random word in the cookie workspace.
3104  */
3105 static inline u32 tcp_cookie_work(const u32 *ws, const int n)
3106 {
3107         return ws[COOKIE_DIGEST_WORDS + ((COOKIE_MESSAGE_WORDS-1) & ws[n])];
3108 }
3109
3110 /* Fill bakery[COOKIE_WORKSPACE_WORDS] with generator, updating as needed.
3111  * Called in softirq context.
3112  * Returns: 0 for success.
3113  */
3114 int tcp_cookie_generator(u32 *bakery)
3115 {
3116         unsigned long jiffy = jiffies;
3117
3118         if (unlikely(time_after_eq(jiffy, tcp_secret_generating->expires))) {
3119                 spin_lock_bh(&tcp_secret_locker);
3120                 if (!time_after_eq(jiffy, tcp_secret_generating->expires)) {
3121                         /* refreshed by another */
3122                         memcpy(bakery,
3123                                &tcp_secret_generating->secrets[0],
3124                                COOKIE_WORKSPACE_WORDS);
3125                 } else {
3126                         /* still needs refreshing */
3127                         get_random_bytes(bakery, COOKIE_WORKSPACE_WORDS);
3128
3129                         /* The first time, paranoia assumes that the
3130                          * randomization function isn't as strong.  But,
3131                          * this secret initialization is delayed until
3132                          * the last possible moment (packet arrival).
3133                          * Although that time is observable, it is
3134                          * unpredictably variable.  Mash in the most
3135                          * volatile clock bits available, and expire the
3136                          * secret extra quickly.
3137                          */
3138                         if (unlikely(tcp_secret_primary->expires ==
3139                                      tcp_secret_secondary->expires)) {
3140                                 struct timespec tv;
3141
3142                                 getnstimeofday(&tv);
3143                                 bakery[COOKIE_DIGEST_WORDS+0] ^=
3144                                         (u32)tv.tv_nsec;
3145
3146                                 tcp_secret_secondary->expires = jiffy
3147                                         + TCP_SECRET_1MSL
3148                                         + (0x0f & tcp_cookie_work(bakery, 0));
3149                         } else {
3150                                 tcp_secret_secondary->expires = jiffy
3151                                         + TCP_SECRET_LIFE
3152                                         + (0xff & tcp_cookie_work(bakery, 1));
3153                                 tcp_secret_primary->expires = jiffy
3154                                         + TCP_SECRET_2MSL
3155                                         + (0x1f & tcp_cookie_work(bakery, 2));
3156                         }
3157                         memcpy(&tcp_secret_secondary->secrets[0],
3158                                bakery, COOKIE_WORKSPACE_WORDS);
3159
3160                         rcu_assign_pointer(tcp_secret_generating,
3161                                            tcp_secret_secondary);
3162                         rcu_assign_pointer(tcp_secret_retiring,
3163                                            tcp_secret_primary);
3164                         /*
3165                          * Neither call_rcu() nor synchronize_rcu() needed.
3166                          * Retiring data is not freed.  It is replaced after
3167                          * further (locked) pointer updates, and a quiet time
3168                          * (minimum 1MSL, maximum LIFE - 2MSL).
3169                          */
3170                 }
3171                 spin_unlock_bh(&tcp_secret_locker);
3172         } else {
3173                 rcu_read_lock_bh();
3174                 memcpy(bakery,
3175                        &rcu_dereference(tcp_secret_generating)->secrets[0],
3176                        COOKIE_WORKSPACE_WORDS);
3177                 rcu_read_unlock_bh();
3178         }
3179         return 0;
3180 }
3181 EXPORT_SYMBOL(tcp_cookie_generator);
3182
3183 void tcp_done(struct sock *sk)
3184 {
3185         if (sk->sk_state == TCP_SYN_SENT || sk->sk_state == TCP_SYN_RECV)
3186                 TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_ATTEMPTFAILS);
3187
3188         tcp_set_state(sk, TCP_CLOSE);
3189         tcp_clear_xmit_timers(sk);
3190
3191         sk->sk_shutdown = SHUTDOWN_MASK;
3192
3193         if (!sock_flag(sk, SOCK_DEAD))
3194                 sk->sk_state_change(sk);
3195         else
3196                 inet_csk_destroy_sock(sk);
3197 }
3198 EXPORT_SYMBOL_GPL(tcp_done);
3199
3200 extern struct tcp_congestion_ops tcp_reno;
3201
3202 static __initdata unsigned long thash_entries;
3203 static int __init set_thash_entries(char *str)
3204 {
3205         if (!str)
3206                 return 0;
3207         thash_entries = simple_strtoul(str, &str, 0);
3208         return 1;
3209 }
3210 __setup("thash_entries=", set_thash_entries);
3211
3212 void __init tcp_init(void)
3213 {
3214         struct sk_buff *skb = NULL;
3215         unsigned long nr_pages, limit;
3216         int i, max_share, cnt;
3217         unsigned long jiffy = jiffies;
3218
3219         BUILD_BUG_ON(sizeof(struct tcp_skb_cb) > sizeof(skb->cb));
3220
3221         percpu_counter_init(&tcp_sockets_allocated, 0);
3222         percpu_counter_init(&tcp_orphan_count, 0);
3223         tcp_hashinfo.bind_bucket_cachep =
3224                 kmem_cache_create("tcp_bind_bucket",
3225                                   sizeof(struct inet_bind_bucket), 0,
3226                                   SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
3227
3228         /* Size and allocate the main established and bind bucket
3229          * hash tables.
3230          *
3231          * The methodology is similar to that of the buffer cache.
3232          */
3233         tcp_hashinfo.ehash =
3234                 alloc_large_system_hash("TCP established",
3235                                         sizeof(struct inet_ehash_bucket),
3236                                         thash_entries,
3237                                         (totalram_pages >= 128 * 1024) ?
3238                                         13 : 15,
3239                                         0,
3240                                         NULL,
3241                                         &tcp_hashinfo.ehash_mask,
3242                                         thash_entries ? 0 : 512 * 1024);
3243         for (i = 0; i <= tcp_hashinfo.ehash_mask; i++) {
3244                 INIT_HLIST_NULLS_HEAD(&tcp_hashinfo.ehash[i].chain, i);
3245                 INIT_HLIST_NULLS_HEAD(&tcp_hashinfo.ehash[i].twchain, i);
3246         }
3247         if (inet_ehash_locks_alloc(&tcp_hashinfo))
3248                 panic("TCP: failed to alloc ehash_locks");
3249         tcp_hashinfo.bhash =
3250                 alloc_large_system_hash("TCP bind",
3251                                         sizeof(struct inet_bind_hashbucket),
3252                                         tcp_hashinfo.ehash_mask + 1,
3253                                         (totalram_pages >= 128 * 1024) ?
3254                                         13 : 15,
3255                                         0,
3256                                         &tcp_hashinfo.bhash_size,
3257                                         NULL,
3258                                         64 * 1024);
3259         tcp_hashinfo.bhash_size = 1 << tcp_hashinfo.bhash_size;
3260         for (i = 0; i < tcp_hashinfo.bhash_size; i++) {
3261                 spin_lock_init(&tcp_hashinfo.bhash[i].lock);
3262                 INIT_HLIST_HEAD(&tcp_hashinfo.bhash[i].chain);
3263         }
3264
3265
3266         cnt = tcp_hashinfo.ehash_mask + 1;
3267
3268         tcp_death_row.sysctl_max_tw_buckets = cnt / 2;
3269         sysctl_tcp_max_orphans = cnt / 2;
3270         sysctl_max_syn_backlog = max(128, cnt / 256);
3271
3272         /* Set the pressure threshold to be a fraction of global memory that
3273          * is up to 1/2 at 256 MB, decreasing toward zero with the amount of
3274          * memory, with a floor of 128 pages.
3275          */
3276         nr_pages = totalram_pages - totalhigh_pages;
3277         limit = min(nr_pages, 1UL<<(28-PAGE_SHIFT)) >> (20-PAGE_SHIFT);
3278         limit = (limit * (nr_pages >> (20-PAGE_SHIFT))) >> (PAGE_SHIFT-11);
3279         limit = max(limit, 128UL);
3280         sysctl_tcp_mem[0] = limit / 4 * 3;
3281         sysctl_tcp_mem[1] = limit;
3282         sysctl_tcp_mem[2] = sysctl_tcp_mem[0] * 2;
3283
3284         /* Set per-socket limits to no more than 1/128 the pressure threshold */
3285         limit = ((unsigned long)sysctl_tcp_mem[1]) << (PAGE_SHIFT - 7);
3286         max_share = min(4UL*1024*1024, limit);
3287
3288         sysctl_tcp_wmem[0] = SK_MEM_QUANTUM;
3289         sysctl_tcp_wmem[1] = 16*1024;
3290         sysctl_tcp_wmem[2] = max(64*1024, max_share);
3291
3292         sysctl_tcp_rmem[0] = SK_MEM_QUANTUM;
3293         sysctl_tcp_rmem[1] = 87380;
3294         sysctl_tcp_rmem[2] = max(87380, max_share);
3295
3296         printk(KERN_INFO "TCP: Hash tables configured "
3297                "(established %u bind %u)\n",
3298                tcp_hashinfo.ehash_mask + 1, tcp_hashinfo.bhash_size);
3299
3300         tcp_register_congestion_control(&tcp_reno);
3301
3302         memset(&tcp_secret_one.secrets[0], 0, sizeof(tcp_secret_one.secrets));
3303         memset(&tcp_secret_two.secrets[0], 0, sizeof(tcp_secret_two.secrets));
3304         tcp_secret_one.expires = jiffy; /* past due */
3305         tcp_secret_two.expires = jiffy; /* past due */
3306         tcp_secret_generating = &tcp_secret_one;
3307         tcp_secret_primary = &tcp_secret_one;
3308         tcp_secret_retiring = &tcp_secret_two;
3309         tcp_secret_secondary = &tcp_secret_two;
3310 }