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