git.oblomov.eu Git - linux-2.6/blob - net/ipv4/inet_connection_sock.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  *              Support for INET connection oriented protocols.
   7  *
   8  * Authors:     See the TCP sources
   9  *
  10  *              This program is free software; you can redistribute it and/or
  11  *              modify it under the terms of the GNU General Public License
  12  *              as published by the Free Software Foundation; either version
  13  *              2 of the License, or(at your option) any later version.
  14  */
  15
  16 #include <linux/module.h>
  17 #include <linux/jhash.h>
  18
  19 #include <net/inet_connection_sock.h>
  20 #include <net/inet_hashtables.h>
  21 #include <net/inet_timewait_sock.h>
  22 #include <net/ip.h>
  23 #include <net/route.h>
  24 #include <net/tcp_states.h>
  25 #include <net/xfrm.h>
  26
  27 #ifdef INET_CSK_DEBUG
  28 const char inet_csk_timer_bug_msg[] = "inet_csk BUG: unknown timer value\n";
  29 EXPORT_SYMBOL(inet_csk_timer_bug_msg);
  30 #endif
  31
  32 /*
  33  * This struct holds the first and last local port number.
  34  */
  35 struct local_ports sysctl_local_ports __read_mostly = {
  36         .lock = SEQLOCK_UNLOCKED,
  37         .range = { 32768, 61000 },
  38 };
  39
  40 void inet_get_local_port_range(int *low, int *high)
  41 {
  42         unsigned seq;
  43         do {
  44                 seq = read_seqbegin(&sysctl_local_ports.lock);
  45
  46                 *low = sysctl_local_ports.range[0];
  47                 *high = sysctl_local_ports.range[1];
  48         } while (read_seqretry(&sysctl_local_ports.lock, seq));
  49 }
  50 EXPORT_SYMBOL(inet_get_local_port_range);
  51
  52 int inet_csk_bind_conflict(const struct sock *sk,
  53                            const struct inet_bind_bucket *tb)
  54 {
  55         const __be32 sk_rcv_saddr = inet_rcv_saddr(sk);
  56         struct sock *sk2;
  57         struct hlist_node *node;
  58         int reuse = sk->sk_reuse;
  59
  60         /*
  61          * Unlike other sk lookup places we do not check
  62          * for sk_net here, since _all_ the socks listed
  63          * in tb->owners list belong to the same net - the
  64          * one this bucket belongs to.
  65          */
  66
  67         sk_for_each_bound(sk2, node, &tb->owners) {
  68                 if (sk != sk2 &&
  69                     !inet_v6_ipv6only(sk2) &&
  70                     (!sk->sk_bound_dev_if ||
  71                      !sk2->sk_bound_dev_if ||
  72                      sk->sk_bound_dev_if == sk2->sk_bound_dev_if)) {
  73                         if (!reuse || !sk2->sk_reuse ||
  74                             sk2->sk_state == TCP_LISTEN) {
  75                                 const __be32 sk2_rcv_saddr = inet_rcv_saddr(sk2);
  76                                 if (!sk2_rcv_saddr || !sk_rcv_saddr ||
  77                                     sk2_rcv_saddr == sk_rcv_saddr)
  78                                         break;
  79                         }
  80                 }
  81         }
  82         return node != NULL;
  83 }
  84
  85 EXPORT_SYMBOL_GPL(inet_csk_bind_conflict);
  86
  87 /* Obtain a reference to a local port for the given sock,
  88  * if snum is zero it means select any available local port.
  89  */
  90 int inet_csk_get_port(struct sock *sk, unsigned short snum)
  91 {
  92         struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
  93         struct inet_bind_hashbucket *head;
  94         struct hlist_node *node;
  95         struct inet_bind_bucket *tb;
  96         int ret, attempts = 5;
  97         struct net *net = sock_net(sk);
  98         int smallest_size = -1, smallest_rover;
  99
 100         local_bh_disable();
 101         if (!snum) {
 102                 int remaining, rover, low, high;
 103
 104 again:
 105                 inet_get_local_port_range(&low, &high);
 106                 remaining = (high - low) + 1;
 107                 smallest_rover = rover = net_random() % remaining + low;
 108
 109                 smallest_size = -1;
 110                 do {
 111                         head = &hashinfo->bhash[inet_bhashfn(net, rover,
 112                                         hashinfo->bhash_size)];
 113                         spin_lock(&head->lock);
 114                         inet_bind_bucket_for_each(tb, node, &head->chain)
 115                                 if (ib_net(tb) == net && tb->port == rover) {
 116                                         if (tb->fastreuse > 0 &&
 117                                             sk->sk_reuse &&
 118                                             sk->sk_state != TCP_LISTEN &&
 119                                             (tb->num_owners < smallest_size || smallest_size == -1)) {
 120                                                 smallest_size = tb->num_owners;
 121                                                 smallest_rover = rover;
 122                                                 if (atomic_read(&hashinfo->bsockets) > (high - low) + 1) {
 123                                                         spin_unlock(&head->lock);
 124                                                         snum = smallest_rover;
 125                                                         goto have_snum;
 126                                                 }
 127                                         }
 128                                         goto next;
 129                                 }
 130                         break;
 131                 next:
 132                         spin_unlock(&head->lock);
 133                         if (++rover > high)
 134                                 rover = low;
 135                 } while (--remaining > 0);
 136
 137                 /* Exhausted local port range during search?  It is not
 138                  * possible for us to be holding one of the bind hash
 139                  * locks if this test triggers, because if 'remaining'
 140                  * drops to zero, we broke out of the do/while loop at
 141                  * the top level, not from the 'break;' statement.
 142                  */
 143                 ret = 1;
 144                 if (remaining <= 0) {
 145                         if (smallest_size != -1) {
 146                                 snum = smallest_rover;
 147                                 goto have_snum;
 148                         }
 149                         goto fail;
 150                 }
 151                 /* OK, here is the one we will use.  HEAD is
 152                  * non-NULL and we hold it's mutex.
 153                  */
 154                 snum = rover;
 155         } else {
 156 have_snum:
 157                 head = &hashinfo->bhash[inet_bhashfn(net, snum,
 158                                 hashinfo->bhash_size)];
 159                 spin_lock(&head->lock);
 160                 inet_bind_bucket_for_each(tb, node, &head->chain)
 161                         if (ib_net(tb) == net && tb->port == snum)
 162                                 goto tb_found;
 163         }
 164         tb = NULL;
 165         goto tb_not_found;
 166 tb_found:
 167         if (!hlist_empty(&tb->owners)) {
 168                 if (tb->fastreuse > 0 &&
 169                     sk->sk_reuse && sk->sk_state != TCP_LISTEN &&
 170                     smallest_size == -1) {
 171                         goto success;
 172                 } else {
 173                         ret = 1;
 174                         if (inet_csk(sk)->icsk_af_ops->bind_conflict(sk, tb)) {
 175                                 if (sk->sk_reuse && sk->sk_state != TCP_LISTEN &&
 176                                     smallest_size != -1 && --attempts >= 0) {
 177                                         spin_unlock(&head->lock);
 178                                         goto again;
 179                                 }
 180                                 goto fail_unlock;
 181                         }
 182                 }
 183         }
 184 tb_not_found:
 185         ret = 1;
 186         if (!tb && (tb = inet_bind_bucket_create(hashinfo->bind_bucket_cachep,
 187                                         net, head, snum)) == NULL)
 188                 goto fail_unlock;
 189         if (hlist_empty(&tb->owners)) {
 190                 if (sk->sk_reuse && sk->sk_state != TCP_LISTEN)
 191                         tb->fastreuse = 1;
 192                 else
 193                         tb->fastreuse = 0;
 194         } else if (tb->fastreuse &&
 195                    (!sk->sk_reuse || sk->sk_state == TCP_LISTEN))
 196                 tb->fastreuse = 0;
 197 success:
 198         if (!inet_csk(sk)->icsk_bind_hash)
 199                 inet_bind_hash(sk, tb, snum);
 200         WARN_ON(inet_csk(sk)->icsk_bind_hash != tb);
 201         ret = 0;
 202
 203 fail_unlock:
 204         spin_unlock(&head->lock);
 205 fail:
 206         local_bh_enable();
 207         return ret;
 208 }
 209
 210 EXPORT_SYMBOL_GPL(inet_csk_get_port);
 211
 212 /*
 213  * Wait for an incoming connection, avoid race conditions. This must be called
 214  * with the socket locked.
 215  */
 216 static int inet_csk_wait_for_connect(struct sock *sk, long timeo)
 217 {
 218         struct inet_connection_sock *icsk = inet_csk(sk);
 219         DEFINE_WAIT(wait);
 220         int err;
 221
 222         /*
 223          * True wake-one mechanism for incoming connections: only
 224          * one process gets woken up, not the 'whole herd'.
 225          * Since we do not 'race & poll' for established sockets
 226          * anymore, the common case will execute the loop only once.
 227          *
 228          * Subtle issue: "add_wait_queue_exclusive()" will be added
 229          * after any current non-exclusive waiters, and we know that
 230          * it will always _stay_ after any new non-exclusive waiters
 231          * because all non-exclusive waiters are added at the
 232          * beginning of the wait-queue. As such, it's ok to "drop"
 233          * our exclusiveness temporarily when we get woken up without
 234          * having to remove and re-insert us on the wait queue.
 235          */
 236         for (;;) {
 237                 prepare_to_wait_exclusive(sk->sk_sleep, &wait,
 238                                           TASK_INTERRUPTIBLE);
 239                 release_sock(sk);
 240                 if (reqsk_queue_empty(&icsk->icsk_accept_queue))
 241                         timeo = schedule_timeout(timeo);
 242                 lock_sock(sk);
 243                 err = 0;
 244                 if (!reqsk_queue_empty(&icsk->icsk_accept_queue))
 245                         break;
 246                 err = -EINVAL;
 247                 if (sk->sk_state != TCP_LISTEN)
 248                         break;
 249                 err = sock_intr_errno(timeo);
 250                 if (signal_pending(current))
 251                         break;
 252                 err = -EAGAIN;
 253                 if (!timeo)
 254                         break;
 255         }
 256         finish_wait(sk->sk_sleep, &wait);
 257         return err;
 258 }
 259
 260 /*
 261  * This will accept the next outstanding connection.
 262  */
 263 struct sock *inet_csk_accept(struct sock *sk, int flags, int *err)
 264 {
 265         struct inet_connection_sock *icsk = inet_csk(sk);
 266         struct sock *newsk;
 267         int error;
 268
 269         lock_sock(sk);
 270
 271         /* We need to make sure that this socket is listening,
 272          * and that it has something pending.
 273          */
 274         error = -EINVAL;
 275         if (sk->sk_state != TCP_LISTEN)
 276                 goto out_err;
 277
 278         /* Find already established connection */
 279         if (reqsk_queue_empty(&icsk->icsk_accept_queue)) {
 280                 long timeo = sock_rcvtimeo(sk, flags & O_NONBLOCK);
 281
 282                 /* If this is a non blocking socket don't sleep */
 283                 error = -EAGAIN;
 284                 if (!timeo)
 285                         goto out_err;
 286
 287                 error = inet_csk_wait_for_connect(sk, timeo);
 288                 if (error)
 289                         goto out_err;
 290         }
 291
 292         newsk = reqsk_queue_get_child(&icsk->icsk_accept_queue, sk);
 293         WARN_ON(newsk->sk_state == TCP_SYN_RECV);
 294 out:
 295         release_sock(sk);
 296         return newsk;
 297 out_err:
 298         newsk = NULL;
 299         *err = error;
 300         goto out;
 301 }
 302
 303 EXPORT_SYMBOL(inet_csk_accept);
 304
 305 /*
 306  * Using different timers for retransmit, delayed acks and probes
 307  * We may wish use just one timer maintaining a list of expire jiffies
 308  * to optimize.
 309  */
 310 void inet_csk_init_xmit_timers(struct sock *sk,
 311                                void (*retransmit_handler)(unsigned long),
 312                                void (*delack_handler)(unsigned long),
 313                                void (*keepalive_handler)(unsigned long))
 314 {
 315         struct inet_connection_sock *icsk = inet_csk(sk);
 316
 317         setup_timer(&icsk->icsk_retransmit_timer, retransmit_handler,
 318                         (unsigned long)sk);
 319         setup_timer(&icsk->icsk_delack_timer, delack_handler,
 320                         (unsigned long)sk);
 321         setup_timer(&sk->sk_timer, keepalive_handler, (unsigned long)sk);
 322         icsk->icsk_pending = icsk->icsk_ack.pending = 0;
 323 }
 324
 325 EXPORT_SYMBOL(inet_csk_init_xmit_timers);
 326
 327 void inet_csk_clear_xmit_timers(struct sock *sk)
 328 {
 329         struct inet_connection_sock *icsk = inet_csk(sk);
 330
 331         icsk->icsk_pending = icsk->icsk_ack.pending = icsk->icsk_ack.blocked = 0;
 332
 333         sk_stop_timer(sk, &icsk->icsk_retransmit_timer);
 334         sk_stop_timer(sk, &icsk->icsk_delack_timer);
 335         sk_stop_timer(sk, &sk->sk_timer);
 336 }
 337
 338 EXPORT_SYMBOL(inet_csk_clear_xmit_timers);
 339
 340 void inet_csk_delete_keepalive_timer(struct sock *sk)
 341 {
 342         sk_stop_timer(sk, &sk->sk_timer);
 343 }
 344
 345 EXPORT_SYMBOL(inet_csk_delete_keepalive_timer);
 346
 347 void inet_csk_reset_keepalive_timer(struct sock *sk, unsigned long len)
 348 {
 349         sk_reset_timer(sk, &sk->sk_timer, jiffies + len);
 350 }
 351
 352 EXPORT_SYMBOL(inet_csk_reset_keepalive_timer);
 353
 354 struct dst_entry *inet_csk_route_req(struct sock *sk,
 355                                      const struct request_sock *req)
 356 {
 357         struct rtable *rt;
 358         const struct inet_request_sock *ireq = inet_rsk(req);
 359         struct ip_options *opt = inet_rsk(req)->opt;
 360         struct flowi fl = { .oif = sk->sk_bound_dev_if,
 361                             .nl_u = { .ip4_u =
 362                                       { .daddr = ((opt && opt->srr) ?
 363                                                   opt->faddr :
 364                                                   ireq->rmt_addr),
 365                                         .saddr = ireq->loc_addr,
 366                                         .tos = RT_CONN_FLAGS(sk) } },
 367                             .proto = sk->sk_protocol,
 368                             .flags = inet_sk_flowi_flags(sk),
 369                             .uli_u = { .ports =
 370                                        { .sport = inet_sk(sk)->sport,
 371                                          .dport = ireq->rmt_port } } };
 372         struct net *net = sock_net(sk);
 373
 374         security_req_classify_flow(req, &fl);
 375         if (ip_route_output_flow(net, &rt, &fl, sk, 0))
 376                 goto no_route;
 377         if (opt && opt->is_strictroute && rt->rt_dst != rt->rt_gateway)
 378                 goto route_err;
 379         return &rt->u.dst;
 380
 381 route_err:
 382         ip_rt_put(rt);
 383 no_route:
 384         IP_INC_STATS_BH(net, IPSTATS_MIB_OUTNOROUTES);
 385         return NULL;
 386 }
 387
 388 EXPORT_SYMBOL_GPL(inet_csk_route_req);
 389
 390 static inline u32 inet_synq_hash(const __be32 raddr, const __be16 rport,
 391                                  const u32 rnd, const u32 synq_hsize)
 392 {
 393         return jhash_2words((__force u32)raddr, (__force u32)rport, rnd) & (synq_hsize - 1);
 394 }
 395
 396 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
 397 #define AF_INET_FAMILY(fam) ((fam) == AF_INET)
 398 #else
 399 #define AF_INET_FAMILY(fam) 1
 400 #endif
 401
 402 struct request_sock *inet_csk_search_req(const struct sock *sk,
 403                                          struct request_sock ***prevp,
 404                                          const __be16 rport, const __be32 raddr,
 405                                          const __be32 laddr)
 406 {
 407         const struct inet_connection_sock *icsk = inet_csk(sk);
 408         struct listen_sock *lopt = icsk->icsk_accept_queue.listen_opt;
 409         struct request_sock *req, **prev;
 410
 411         for (prev = &lopt->syn_table[inet_synq_hash(raddr, rport, lopt->hash_rnd,
 412                                                     lopt->nr_table_entries)];
 413              (req = *prev) != NULL;
 414              prev = &req->dl_next) {
 415                 const struct inet_request_sock *ireq = inet_rsk(req);
 416
 417                 if (ireq->rmt_port == rport &&
 418                     ireq->rmt_addr == raddr &&
 419                     ireq->loc_addr == laddr &&
 420                     AF_INET_FAMILY(req->rsk_ops->family)) {
 421                         WARN_ON(req->sk);
 422                         *prevp = prev;
 423                         break;
 424                 }
 425         }
 426
 427         return req;
 428 }
 429
 430 EXPORT_SYMBOL_GPL(inet_csk_search_req);
 431
 432 void inet_csk_reqsk_queue_hash_add(struct sock *sk, struct request_sock *req,
 433                                    unsigned long timeout)
 434 {
 435         struct inet_connection_sock *icsk = inet_csk(sk);
 436         struct listen_sock *lopt = icsk->icsk_accept_queue.listen_opt;
 437         const u32 h = inet_synq_hash(inet_rsk(req)->rmt_addr, inet_rsk(req)->rmt_port,
 438                                      lopt->hash_rnd, lopt->nr_table_entries);
 439
 440         reqsk_queue_hash_req(&icsk->icsk_accept_queue, h, req, timeout);
 441         inet_csk_reqsk_queue_added(sk, timeout);
 442 }
 443
 444 /* Only thing we need from tcp.h */
 445 extern int sysctl_tcp_synack_retries;
 446
 447 EXPORT_SYMBOL_GPL(inet_csk_reqsk_queue_hash_add);
 448
 449 void inet_csk_reqsk_queue_prune(struct sock *parent,
 450                                 const unsigned long interval,
 451                                 const unsigned long timeout,
 452                                 const unsigned long max_rto)
 453 {
 454         struct inet_connection_sock *icsk = inet_csk(parent);
 455         struct request_sock_queue *queue = &icsk->icsk_accept_queue;
 456         struct listen_sock *lopt = queue->listen_opt;
 457         int max_retries = icsk->icsk_syn_retries ? : sysctl_tcp_synack_retries;
 458         int thresh = max_retries;
 459         unsigned long now = jiffies;
 460         struct request_sock **reqp, *req;
 461         int i, budget;
 462
 463         if (lopt == NULL || lopt->qlen == 0)
 464                 return;
 465
 466         /* Normally all the openreqs are young and become mature
 467          * (i.e. converted to established socket) for first timeout.
 468          * If synack was not acknowledged for 3 seconds, it means
 469          * one of the following things: synack was lost, ack was lost,
 470          * rtt is high or nobody planned to ack (i.e. synflood).
 471          * When server is a bit loaded, queue is populated with old
 472          * open requests, reducing effective size of queue.
 473          * When server is well loaded, queue size reduces to zero
 474          * after several minutes of work. It is not synflood,
 475          * it is normal operation. The solution is pruning
 476          * too old entries overriding normal timeout, when
 477          * situation becomes dangerous.
 478          *
 479          * Essentially, we reserve half of room for young
 480          * embrions; and abort old ones without pity, if old
 481          * ones are about to clog our table.
 482          */
 483         if (lopt->qlen>>(lopt->max_qlen_log-1)) {
 484                 int young = (lopt->qlen_young<<1);
 485
 486                 while (thresh > 2) {
 487                         if (lopt->qlen < young)
 488                                 break;
 489                         thresh--;
 490                         young <<= 1;
 491                 }
 492         }
 493
 494         if (queue->rskq_defer_accept)
 495                 max_retries = queue->rskq_defer_accept;
 496
 497         budget = 2 * (lopt->nr_table_entries / (timeout / interval));
 498         i = lopt->clock_hand;
 499
 500         do {
 501                 reqp=&lopt->syn_table[i];
 502                 while ((req = *reqp) != NULL) {
 503                         if (time_after_eq(now, req->expires)) {
 504                                 if ((req->retrans < thresh ||
 505                                      (inet_rsk(req)->acked && req->retrans < max_retries))
 506                                     && !req->rsk_ops->rtx_syn_ack(parent, req)) {
 507                                         unsigned long timeo;
 508
 509                                         if (req->retrans++ == 0)
 510                                                 lopt->qlen_young--;
 511                                         timeo = min((timeout << req->retrans), max_rto);
 512                                         req->expires = now + timeo;
 513                                         reqp = &req->dl_next;
 514                                         continue;
 515                                 }
 516
 517                                 /* Drop this request */
 518                                 inet_csk_reqsk_queue_unlink(parent, req, reqp);
 519                                 reqsk_queue_removed(queue, req);
 520                                 reqsk_free(req);
 521                                 continue;
 522                         }
 523                         reqp = &req->dl_next;
 524                 }
 525
 526                 i = (i + 1) & (lopt->nr_table_entries - 1);
 527
 528         } while (--budget > 0);
 529
 530         lopt->clock_hand = i;
 531
 532         if (lopt->qlen)
 533                 inet_csk_reset_keepalive_timer(parent, interval);
 534 }
 535
 536 EXPORT_SYMBOL_GPL(inet_csk_reqsk_queue_prune);
 537
 538 struct sock *inet_csk_clone(struct sock *sk, const struct request_sock *req,
 539                             const gfp_t priority)
 540 {
 541         struct sock *newsk = sk_clone(sk, priority);
 542
 543         if (newsk != NULL) {
 544                 struct inet_connection_sock *newicsk = inet_csk(newsk);
 545
 546                 newsk->sk_state = TCP_SYN_RECV;
 547                 newicsk->icsk_bind_hash = NULL;
 548
 549                 inet_sk(newsk)->dport = inet_rsk(req)->rmt_port;
 550                 inet_sk(newsk)->num = ntohs(inet_rsk(req)->loc_port);
 551                 inet_sk(newsk)->sport = inet_rsk(req)->loc_port;
 552                 newsk->sk_write_space = sk_stream_write_space;
 553
 554                 newicsk->icsk_retransmits = 0;
 555                 newicsk->icsk_backoff     = 0;
 556                 newicsk->icsk_probes_out  = 0;
 557
 558                 /* Deinitialize accept_queue to trap illegal accesses. */
 559                 memset(&newicsk->icsk_accept_queue, 0, sizeof(newicsk->icsk_accept_queue));
 560
 561                 security_inet_csk_clone(newsk, req);
 562         }
 563         return newsk;
 564 }
 565
 566 EXPORT_SYMBOL_GPL(inet_csk_clone);
 567
 568 /*
 569  * At this point, there should be no process reference to this
 570  * socket, and thus no user references at all.  Therefore we
 571  * can assume the socket waitqueue is inactive and nobody will
 572  * try to jump onto it.
 573  */
 574 void inet_csk_destroy_sock(struct sock *sk)
 575 {
 576         WARN_ON(sk->sk_state != TCP_CLOSE);
 577         WARN_ON(!sock_flag(sk, SOCK_DEAD));
 578
 579         /* It cannot be in hash table! */
 580         WARN_ON(!sk_unhashed(sk));
 581
 582         /* If it has not 0 inet_sk(sk)->num, it must be bound */
 583         WARN_ON(inet_sk(sk)->num && !inet_csk(sk)->icsk_bind_hash);
 584
 585         sk->sk_prot->destroy(sk);
 586
 587         sk_stream_kill_queues(sk);
 588
 589         xfrm_sk_free_policy(sk);
 590
 591         sk_refcnt_debug_release(sk);
 592
 593         percpu_counter_dec(sk->sk_prot->orphan_count);
 594         sock_put(sk);
 595 }
 596
 597 EXPORT_SYMBOL(inet_csk_destroy_sock);
 598
 599 int inet_csk_listen_start(struct sock *sk, const int nr_table_entries)
 600 {
 601         struct inet_sock *inet = inet_sk(sk);
 602         struct inet_connection_sock *icsk = inet_csk(sk);
 603         int rc = reqsk_queue_alloc(&icsk->icsk_accept_queue, nr_table_entries);
 604
 605         if (rc != 0)
 606                 return rc;
 607
 608         sk->sk_max_ack_backlog = 0;
 609         sk->sk_ack_backlog = 0;
 610         inet_csk_delack_init(sk);
 611
 612         /* There is race window here: we announce ourselves listening,
 613          * but this transition is still not validated by get_port().
 614          * It is OK, because this socket enters to hash table only
 615          * after validation is complete.
 616          */
 617         sk->sk_state = TCP_LISTEN;
 618         if (!sk->sk_prot->get_port(sk, inet->num)) {
 619                 inet->sport = htons(inet->num);
 620
 621                 sk_dst_reset(sk);
 622                 sk->sk_prot->hash(sk);
 623
 624                 return 0;
 625         }
 626
 627         sk->sk_state = TCP_CLOSE;
 628         __reqsk_queue_destroy(&icsk->icsk_accept_queue);
 629         return -EADDRINUSE;
 630 }
 631
 632 EXPORT_SYMBOL_GPL(inet_csk_listen_start);
 633
 634 /*
 635  *      This routine closes sockets which have been at least partially
 636  *      opened, but not yet accepted.
 637  */
 638 void inet_csk_listen_stop(struct sock *sk)
 639 {
 640         struct inet_connection_sock *icsk = inet_csk(sk);
 641         struct request_sock *acc_req;
 642         struct request_sock *req;
 643
 644         inet_csk_delete_keepalive_timer(sk);
 645
 646         /* make all the listen_opt local to us */
 647         acc_req = reqsk_queue_yank_acceptq(&icsk->icsk_accept_queue);
 648
 649         /* Following specs, it would be better either to send FIN
 650          * (and enter FIN-WAIT-1, it is normal close)
 651          * or to send active reset (abort).
 652          * Certainly, it is pretty dangerous while synflood, but it is
 653          * bad justification for our negligence 8)
 654          * To be honest, we are not able to make either
 655          * of the variants now.                 --ANK
 656          */
 657         reqsk_queue_destroy(&icsk->icsk_accept_queue);
 658
 659         while ((req = acc_req) != NULL) {
 660                 struct sock *child = req->sk;
 661
 662                 acc_req = req->dl_next;
 663
 664                 local_bh_disable();
 665                 bh_lock_sock(child);
 666                 WARN_ON(sock_owned_by_user(child));
 667                 sock_hold(child);
 668
 669                 sk->sk_prot->disconnect(child, O_NONBLOCK);
 670
 671                 sock_orphan(child);
 672
 673                 percpu_counter_inc(sk->sk_prot->orphan_count);
 674
 675                 inet_csk_destroy_sock(child);
 676
 677                 bh_unlock_sock(child);
 678                 local_bh_enable();
 679                 sock_put(child);
 680
 681                 sk_acceptq_removed(sk);
 682                 __reqsk_free(req);
 683         }
 684         WARN_ON(sk->sk_ack_backlog);
 685 }
 686
 687 EXPORT_SYMBOL_GPL(inet_csk_listen_stop);
 688
 689 void inet_csk_addr2sockaddr(struct sock *sk, struct sockaddr *uaddr)
 690 {
 691         struct sockaddr_in *sin = (struct sockaddr_in *)uaddr;
 692         const struct inet_sock *inet = inet_sk(sk);
 693
 694         sin->sin_family         = AF_INET;
 695         sin->sin_addr.s_addr    = inet->daddr;
 696         sin->sin_port           = inet->dport;
 697 }
 698
 699 EXPORT_SYMBOL_GPL(inet_csk_addr2sockaddr);
 700
 701 #ifdef CONFIG_COMPAT
 702 int inet_csk_compat_getsockopt(struct sock *sk, int level, int optname,
 703                                char __user *optval, int __user *optlen)
 704 {
 705         const struct inet_connection_sock *icsk = inet_csk(sk);
 706
 707         if (icsk->icsk_af_ops->compat_getsockopt != NULL)
 708                 return icsk->icsk_af_ops->compat_getsockopt(sk, level, optname,
 709                                                             optval, optlen);
 710         return icsk->icsk_af_ops->getsockopt(sk, level, optname,
 711                                              optval, optlen);
 712 }
 713
 714 EXPORT_SYMBOL_GPL(inet_csk_compat_getsockopt);
 715
 716 int inet_csk_compat_setsockopt(struct sock *sk, int level, int optname,
 717                                char __user *optval, int optlen)
 718 {
 719         const struct inet_connection_sock *icsk = inet_csk(sk);
 720
 721         if (icsk->icsk_af_ops->compat_setsockopt != NULL)
 722                 return icsk->icsk_af_ops->compat_setsockopt(sk, level, optname,
 723                                                             optval, optlen);
 724         return icsk->icsk_af_ops->setsockopt(sk, level, optname,
 725                                              optval, optlen);
 726 }
 727
 728 EXPORT_SYMBOL_GPL(inet_csk_compat_setsockopt);
 729 #endif