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 unsigned long *sysctl_local_reserved_ports;
  41 EXPORT_SYMBOL(sysctl_local_reserved_ports);
  42
  43 void inet_get_local_port_range(int *low, int *high)
  44 {
  45         unsigned seq;
  46         do {
  47                 seq = read_seqbegin(&sysctl_local_ports.lock);
  48
  49                 *low = sysctl_local_ports.range[0];
  50                 *high = sysctl_local_ports.range[1];
  51         } while (read_seqretry(&sysctl_local_ports.lock, seq));
  52 }
  53 EXPORT_SYMBOL(inet_get_local_port_range);
  54
  55 int inet_csk_bind_conflict(const struct sock *sk,
  56                            const struct inet_bind_bucket *tb)
  57 {
  58         struct sock *sk2;
  59         struct hlist_node *node;
  60         int reuse = sk->sk_reuse;
  61
  62         /*
  63          * Unlike other sk lookup places we do not check
  64          * for sk_net here, since _all_ the socks listed
  65          * in tb->owners list belong to the same net - the
  66          * one this bucket belongs to.
  67          */
  68
  69         sk_for_each_bound(sk2, node, &tb->owners) {
  70                 if (sk != sk2 &&
  71                     !inet_v6_ipv6only(sk2) &&
  72                     (!sk->sk_bound_dev_if ||
  73                      !sk2->sk_bound_dev_if ||
  74                      sk->sk_bound_dev_if == sk2->sk_bound_dev_if)) {
  75                         if (!reuse || !sk2->sk_reuse ||
  76                             sk2->sk_state == TCP_LISTEN) {
  77                                 const __be32 sk2_rcv_saddr = sk_rcv_saddr(sk2);
  78                                 if (!sk2_rcv_saddr || !sk_rcv_saddr(sk) ||
  79                                     sk2_rcv_saddr == sk_rcv_saddr(sk))
  80                                         break;
  81                         }
  82                 }
  83         }
  84         return node != NULL;
  85 }
  86 EXPORT_SYMBOL_GPL(inet_csk_bind_conflict);
  87
  88 /* Obtain a reference to a local port for the given sock,
  89  * if snum is zero it means select any available local port.
  90  */
  91 int inet_csk_get_port(struct sock *sk, unsigned short snum)
  92 {
  93         struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
  94         struct inet_bind_hashbucket *head;
  95         struct hlist_node *node;
  96         struct inet_bind_bucket *tb;
  97         int ret, attempts = 5;
  98         struct net *net = sock_net(sk);
  99         int smallest_size = -1, smallest_rover;
 100
 101         local_bh_disable();
 102         if (!snum) {
 103                 int remaining, rover, low, high;
 104
 105 again:
 106                 inet_get_local_port_range(&low, &high);
 107                 remaining = (high - low) + 1;
 108                 smallest_rover = rover = net_random() % remaining + low;
 109
 110                 smallest_size = -1;
 111                 do {
 112                         if (inet_is_reserved_local_port(rover))
 113                                 goto next_nolock;
 114                         head = &hashinfo->bhash[inet_bhashfn(net, rover,
 115                                         hashinfo->bhash_size)];
 116                         spin_lock(&head->lock);
 117                         inet_bind_bucket_for_each(tb, node, &head->chain)
 118                                 if (net_eq(ib_net(tb), net) && tb->port == rover) {
 119                                         if (tb->fastreuse > 0 &&
 120                                             sk->sk_reuse &&
 121                                             sk->sk_state != TCP_LISTEN &&
 122                                             (tb->num_owners < smallest_size || smallest_size == -1)) {
 123                                                 smallest_size = tb->num_owners;
 124                                                 smallest_rover = rover;
 125                                                 if (atomic_read(&hashinfo->bsockets) > (high - low) + 1) {
 126                                                         spin_unlock(&head->lock);
 127                                                         snum = smallest_rover;
 128                                                         goto have_snum;
 129                                                 }
 130                                         }
 131                                         goto next;
 132                                 }
 133                         break;
 134                 next:
 135                         spin_unlock(&head->lock);
 136                 next_nolock:
 137                         if (++rover > high)
 138                                 rover = low;
 139                 } while (--remaining > 0);
 140
 141                 /* Exhausted local port range during search?  It is not
 142                  * possible for us to be holding one of the bind hash
 143                  * locks if this test triggers, because if 'remaining'
 144                  * drops to zero, we broke out of the do/while loop at
 145                  * the top level, not from the 'break;' statement.
 146                  */
 147                 ret = 1;
 148                 if (remaining <= 0) {
 149                         if (smallest_size != -1) {
 150                                 snum = smallest_rover;
 151                                 goto have_snum;
 152                         }
 153                         goto fail;
 154                 }
 155                 /* OK, here is the one we will use.  HEAD is
 156                  * non-NULL and we hold it's mutex.
 157                  */
 158                 snum = rover;
 159         } else {
 160 have_snum:
 161                 head = &hashinfo->bhash[inet_bhashfn(net, snum,
 162                                 hashinfo->bhash_size)];
 163                 spin_lock(&head->lock);
 164                 inet_bind_bucket_for_each(tb, node, &head->chain)
 165                         if (net_eq(ib_net(tb), net) && tb->port == snum)
 166                                 goto tb_found;
 167         }
 168         tb = NULL;
 169         goto tb_not_found;
 170 tb_found:
 171         if (!hlist_empty(&tb->owners)) {
 172                 if (tb->fastreuse > 0 &&
 173                     sk->sk_reuse && sk->sk_state != TCP_LISTEN &&
 174                     smallest_size == -1) {
 175                         goto success;
 176                 } else {
 177                         ret = 1;
 178                         if (inet_csk(sk)->icsk_af_ops->bind_conflict(sk, tb)) {
 179                                 if (sk->sk_reuse && sk->sk_state != TCP_LISTEN &&
 180                                     smallest_size != -1 && --attempts >= 0) {
 181                                         spin_unlock(&head->lock);
 182                                         goto again;
 183                                 }
 184                                 goto fail_unlock;
 185                         }
 186                 }
 187         }
 188 tb_not_found:
 189         ret = 1;
 190         if (!tb && (tb = inet_bind_bucket_create(hashinfo->bind_bucket_cachep,
 191                                         net, head, snum)) == NULL)
 192                 goto fail_unlock;
 193         if (hlist_empty(&tb->owners)) {
 194                 if (sk->sk_reuse && sk->sk_state != TCP_LISTEN)
 195                         tb->fastreuse = 1;
 196                 else
 197                         tb->fastreuse = 0;
 198         } else if (tb->fastreuse &&
 199                    (!sk->sk_reuse || sk->sk_state == TCP_LISTEN))
 200                 tb->fastreuse = 0;
 201 success:
 202         if (!inet_csk(sk)->icsk_bind_hash)
 203                 inet_bind_hash(sk, tb, snum);
 204         WARN_ON(inet_csk(sk)->icsk_bind_hash != tb);
 205         ret = 0;
 206
 207 fail_unlock:
 208         spin_unlock(&head->lock);
 209 fail:
 210         local_bh_enable();
 211         return ret;
 212 }
 213 EXPORT_SYMBOL_GPL(inet_csk_get_port);
 214
 215 /*
 216  * Wait for an incoming connection, avoid race conditions. This must be called
 217  * with the socket locked.
 218  */
 219 static int inet_csk_wait_for_connect(struct sock *sk, long timeo)
 220 {
 221         struct inet_connection_sock *icsk = inet_csk(sk);
 222         DEFINE_WAIT(wait);
 223         int err;
 224
 225         /*
 226          * True wake-one mechanism for incoming connections: only
 227          * one process gets woken up, not the 'whole herd'.
 228          * Since we do not 'race & poll' for established sockets
 229          * anymore, the common case will execute the loop only once.
 230          *
 231          * Subtle issue: "add_wait_queue_exclusive()" will be added
 232          * after any current non-exclusive waiters, and we know that
 233          * it will always _stay_ after any new non-exclusive waiters
 234          * because all non-exclusive waiters are added at the
 235          * beginning of the wait-queue. As such, it's ok to "drop"
 236          * our exclusiveness temporarily when we get woken up without
 237          * having to remove and re-insert us on the wait queue.
 238          */
 239         for (;;) {
 240                 prepare_to_wait_exclusive(sk_sleep(sk), &wait,
 241                                           TASK_INTERRUPTIBLE);
 242                 release_sock(sk);
 243                 if (reqsk_queue_empty(&icsk->icsk_accept_queue))
 244                         timeo = schedule_timeout(timeo);
 245                 lock_sock(sk);
 246                 err = 0;
 247                 if (!reqsk_queue_empty(&icsk->icsk_accept_queue))
 248                         break;
 249                 err = -EINVAL;
 250                 if (sk->sk_state != TCP_LISTEN)
 251                         break;
 252                 err = sock_intr_errno(timeo);
 253                 if (signal_pending(current))
 254                         break;
 255                 err = -EAGAIN;
 256                 if (!timeo)
 257                         break;
 258         }
 259         finish_wait(sk_sleep(sk), &wait);
 260         return err;
 261 }
 262
 263 /*
 264  * This will accept the next outstanding connection.
 265  */
 266 struct sock *inet_csk_accept(struct sock *sk, int flags, int *err)
 267 {
 268         struct inet_connection_sock *icsk = inet_csk(sk);
 269         struct sock *newsk;
 270         int error;
 271
 272         lock_sock(sk);
 273
 274         /* We need to make sure that this socket is listening,
 275          * and that it has something pending.
 276          */
 277         error = -EINVAL;
 278         if (sk->sk_state != TCP_LISTEN)
 279                 goto out_err;
 280
 281         /* Find already established connection */
 282         if (reqsk_queue_empty(&icsk->icsk_accept_queue)) {
 283                 long timeo = sock_rcvtimeo(sk, flags & O_NONBLOCK);
 284
 285                 /* If this is a non blocking socket don't sleep */
 286                 error = -EAGAIN;
 287                 if (!timeo)
 288                         goto out_err;
 289
 290                 error = inet_csk_wait_for_connect(sk, timeo);
 291                 if (error)
 292                         goto out_err;
 293         }
 294
 295         newsk = reqsk_queue_get_child(&icsk->icsk_accept_queue, sk);
 296         WARN_ON(newsk->sk_state == TCP_SYN_RECV);
 297 out:
 298         release_sock(sk);
 299         return newsk;
 300 out_err:
 301         newsk = NULL;
 302         *err = error;
 303         goto out;
 304 }
 305 EXPORT_SYMBOL(inet_csk_accept);
 306
 307 /*
 308  * Using different timers for retransmit, delayed acks and probes
 309  * We may wish use just one timer maintaining a list of expire jiffies
 310  * to optimize.
 311  */
 312 void inet_csk_init_xmit_timers(struct sock *sk,
 313                                void (*retransmit_handler)(unsigned long),
 314                                void (*delack_handler)(unsigned long),
 315                                void (*keepalive_handler)(unsigned long))
 316 {
 317         struct inet_connection_sock *icsk = inet_csk(sk);
 318
 319         setup_timer(&icsk->icsk_retransmit_timer, retransmit_handler,
 320                         (unsigned long)sk);
 321         setup_timer(&icsk->icsk_delack_timer, delack_handler,
 322                         (unsigned long)sk);
 323         setup_timer(&sk->sk_timer, keepalive_handler, (unsigned long)sk);
 324         icsk->icsk_pending = icsk->icsk_ack.pending = 0;
 325 }
 326 EXPORT_SYMBOL(inet_csk_init_xmit_timers);
 327
 328 void inet_csk_clear_xmit_timers(struct sock *sk)
 329 {
 330         struct inet_connection_sock *icsk = inet_csk(sk);
 331
 332         icsk->icsk_pending = icsk->icsk_ack.pending = icsk->icsk_ack.blocked = 0;
 333
 334         sk_stop_timer(sk, &icsk->icsk_retransmit_timer);
 335         sk_stop_timer(sk, &icsk->icsk_delack_timer);
 336         sk_stop_timer(sk, &sk->sk_timer);
 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 EXPORT_SYMBOL(inet_csk_delete_keepalive_timer);
 345
 346 void inet_csk_reset_keepalive_timer(struct sock *sk, unsigned long len)
 347 {
 348         sk_reset_timer(sk, &sk->sk_timer, jiffies + len);
 349 }
 350 EXPORT_SYMBOL(inet_csk_reset_keepalive_timer);
 351
 352 struct dst_entry *inet_csk_route_req(struct sock *sk,
 353                                      const struct request_sock *req)
 354 {
 355         struct rtable *rt;
 356         const struct inet_request_sock *ireq = inet_rsk(req);
 357         struct ip_options *opt = inet_rsk(req)->opt;
 358         struct flowi fl = { .oif = sk->sk_bound_dev_if,
 359                             .mark = sk->sk_mark,
 360                             .fl4_dst = ((opt && opt->srr) ?
 361                                           opt->faddr : ireq->rmt_addr),
 362                             .fl4_src = ireq->loc_addr,
 363                             .fl4_tos = RT_CONN_FLAGS(sk),
 364                             .proto = sk->sk_protocol,
 365                             .flags = inet_sk_flowi_flags(sk),
 366                             .fl_ip_sport = inet_sk(sk)->inet_sport,
 367                             .fl_ip_dport = ireq->rmt_port };
 368         struct net *net = sock_net(sk);
 369
 370         security_req_classify_flow(req, &fl);
 371         if (ip_route_output_flow(net, &rt, &fl, sk, 0))
 372                 goto no_route;
 373         if (opt && opt->is_strictroute && rt->rt_dst != rt->rt_gateway)
 374                 goto route_err;
 375         return &rt->dst;
 376
 377 route_err:
 378         ip_rt_put(rt);
 379 no_route:
 380         IP_INC_STATS_BH(net, IPSTATS_MIB_OUTNOROUTES);
 381         return NULL;
 382 }
 383 EXPORT_SYMBOL_GPL(inet_csk_route_req);
 384
 385 static inline u32 inet_synq_hash(const __be32 raddr, const __be16 rport,
 386                                  const u32 rnd, const u32 synq_hsize)
 387 {
 388         return jhash_2words((__force u32)raddr, (__force u32)rport, rnd) & (synq_hsize - 1);
 389 }
 390
 391 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
 392 #define AF_INET_FAMILY(fam) ((fam) == AF_INET)
 393 #else
 394 #define AF_INET_FAMILY(fam) 1
 395 #endif
 396
 397 struct request_sock *inet_csk_search_req(const struct sock *sk,
 398                                          struct request_sock ***prevp,
 399                                          const __be16 rport, const __be32 raddr,
 400                                          const __be32 laddr)
 401 {
 402         const struct inet_connection_sock *icsk = inet_csk(sk);
 403         struct listen_sock *lopt = icsk->icsk_accept_queue.listen_opt;
 404         struct request_sock *req, **prev;
 405
 406         for (prev = &lopt->syn_table[inet_synq_hash(raddr, rport, lopt->hash_rnd,
 407                                                     lopt->nr_table_entries)];
 408              (req = *prev) != NULL;
 409              prev = &req->dl_next) {
 410                 const struct inet_request_sock *ireq = inet_rsk(req);
 411
 412                 if (ireq->rmt_port == rport &&
 413                     ireq->rmt_addr == raddr &&
 414                     ireq->loc_addr == laddr &&
 415                     AF_INET_FAMILY(req->rsk_ops->family)) {
 416                         WARN_ON(req->sk);
 417                         *prevp = prev;
 418                         break;
 419                 }
 420         }
 421
 422         return req;
 423 }
 424 EXPORT_SYMBOL_GPL(inet_csk_search_req);
 425
 426 void inet_csk_reqsk_queue_hash_add(struct sock *sk, struct request_sock *req,
 427                                    unsigned long timeout)
 428 {
 429         struct inet_connection_sock *icsk = inet_csk(sk);
 430         struct listen_sock *lopt = icsk->icsk_accept_queue.listen_opt;
 431         const u32 h = inet_synq_hash(inet_rsk(req)->rmt_addr, inet_rsk(req)->rmt_port,
 432                                      lopt->hash_rnd, lopt->nr_table_entries);
 433
 434         reqsk_queue_hash_req(&icsk->icsk_accept_queue, h, req, timeout);
 435         inet_csk_reqsk_queue_added(sk, timeout);
 436 }
 437 EXPORT_SYMBOL_GPL(inet_csk_reqsk_queue_hash_add);
 438
 439 /* Only thing we need from tcp.h */
 440 extern int sysctl_tcp_synack_retries;
 441
 442
 443 /* Decide when to expire the request and when to resend SYN-ACK */
 444 static inline void syn_ack_recalc(struct request_sock *req, const int thresh,
 445                                   const int max_retries,
 446                                   const u8 rskq_defer_accept,
 447                                   int *expire, int *resend)
 448 {
 449         if (!rskq_defer_accept) {
 450                 *expire = req->retrans >= thresh;
 451                 *resend = 1;
 452                 return;
 453         }
 454         *expire = req->retrans >= thresh &&
 455                   (!inet_rsk(req)->acked || req->retrans >= max_retries);
 456         /*
 457          * Do not resend while waiting for data after ACK,
 458          * start to resend on end of deferring period to give
 459          * last chance for data or ACK to create established socket.
 460          */
 461         *resend = !inet_rsk(req)->acked ||
 462                   req->retrans >= rskq_defer_accept - 1;
 463 }
 464
 465 void inet_csk_reqsk_queue_prune(struct sock *parent,
 466                                 const unsigned long interval,
 467                                 const unsigned long timeout,
 468                                 const unsigned long max_rto)
 469 {
 470         struct inet_connection_sock *icsk = inet_csk(parent);
 471         struct request_sock_queue *queue = &icsk->icsk_accept_queue;
 472         struct listen_sock *lopt = queue->listen_opt;
 473         int max_retries = icsk->icsk_syn_retries ? : sysctl_tcp_synack_retries;
 474         int thresh = max_retries;
 475         unsigned long now = jiffies;
 476         struct request_sock **reqp, *req;
 477         int i, budget;
 478
 479         if (lopt == NULL || lopt->qlen == 0)
 480                 return;
 481
 482         /* Normally all the openreqs are young and become mature
 483          * (i.e. converted to established socket) for first timeout.
 484          * If synack was not acknowledged for 3 seconds, it means
 485          * one of the following things: synack was lost, ack was lost,
 486          * rtt is high or nobody planned to ack (i.e. synflood).
 487          * When server is a bit loaded, queue is populated with old
 488          * open requests, reducing effective size of queue.
 489          * When server is well loaded, queue size reduces to zero
 490          * after several minutes of work. It is not synflood,
 491          * it is normal operation. The solution is pruning
 492          * too old entries overriding normal timeout, when
 493          * situation becomes dangerous.
 494          *
 495          * Essentially, we reserve half of room for young
 496          * embrions; and abort old ones without pity, if old
 497          * ones are about to clog our table.
 498          */
 499         if (lopt->qlen>>(lopt->max_qlen_log-1)) {
 500                 int young = (lopt->qlen_young<<1);
 501
 502                 while (thresh > 2) {
 503                         if (lopt->qlen < young)
 504                                 break;
 505                         thresh--;
 506                         young <<= 1;
 507                 }
 508         }
 509
 510         if (queue->rskq_defer_accept)
 511                 max_retries = queue->rskq_defer_accept;
 512
 513         budget = 2 * (lopt->nr_table_entries / (timeout / interval));
 514         i = lopt->clock_hand;
 515
 516         do {
 517                 reqp=&lopt->syn_table[i];
 518                 while ((req = *reqp) != NULL) {
 519                         if (time_after_eq(now, req->expires)) {
 520                                 int expire = 0, resend = 0;
 521
 522                                 syn_ack_recalc(req, thresh, max_retries,
 523                                                queue->rskq_defer_accept,
 524                                                &expire, &resend);
 525                                 if (req->rsk_ops->syn_ack_timeout)
 526                                         req->rsk_ops->syn_ack_timeout(parent, req);
 527                                 if (!expire &&
 528                                     (!resend ||
 529                                      !req->rsk_ops->rtx_syn_ack(parent, req, NULL) ||
 530                                      inet_rsk(req)->acked)) {
 531                                         unsigned long timeo;
 532
 533                                         if (req->retrans++ == 0)
 534                                                 lopt->qlen_young--;
 535                                         timeo = min((timeout << req->retrans), max_rto);
 536                                         req->expires = now + timeo;
 537                                         reqp = &req->dl_next;
 538                                         continue;
 539                                 }
 540
 541                                 /* Drop this request */
 542                                 inet_csk_reqsk_queue_unlink(parent, req, reqp);
 543                                 reqsk_queue_removed(queue, req);
 544                                 reqsk_free(req);
 545                                 continue;
 546                         }
 547                         reqp = &req->dl_next;
 548                 }
 549
 550                 i = (i + 1) & (lopt->nr_table_entries - 1);
 551
 552         } while (--budget > 0);
 553
 554         lopt->clock_hand = i;
 555
 556         if (lopt->qlen)
 557                 inet_csk_reset_keepalive_timer(parent, interval);
 558 }
 559 EXPORT_SYMBOL_GPL(inet_csk_reqsk_queue_prune);
 560
 561 struct sock *inet_csk_clone(struct sock *sk, const struct request_sock *req,
 562                             const gfp_t priority)
 563 {
 564         struct sock *newsk = sk_clone(sk, priority);
 565
 566         if (newsk != NULL) {
 567                 struct inet_connection_sock *newicsk = inet_csk(newsk);
 568
 569                 newsk->sk_state = TCP_SYN_RECV;
 570                 newicsk->icsk_bind_hash = NULL;
 571
 572                 inet_sk(newsk)->inet_dport = inet_rsk(req)->rmt_port;
 573                 inet_sk(newsk)->inet_num = ntohs(inet_rsk(req)->loc_port);
 574                 inet_sk(newsk)->inet_sport = inet_rsk(req)->loc_port;
 575                 newsk->sk_write_space = sk_stream_write_space;
 576
 577                 newicsk->icsk_retransmits = 0;
 578                 newicsk->icsk_backoff     = 0;
 579                 newicsk->icsk_probes_out  = 0;
 580
 581                 /* Deinitialize accept_queue to trap illegal accesses. */
 582                 memset(&newicsk->icsk_accept_queue, 0, sizeof(newicsk->icsk_accept_queue));
 583
 584                 security_inet_csk_clone(newsk, req);
 585         }
 586         return newsk;
 587 }
 588 EXPORT_SYMBOL_GPL(inet_csk_clone);
 589
 590 /*
 591  * At this point, there should be no process reference to this
 592  * socket, and thus no user references at all.  Therefore we
 593  * can assume the socket waitqueue is inactive and nobody will
 594  * try to jump onto it.
 595  */
 596 void inet_csk_destroy_sock(struct sock *sk)
 597 {
 598         WARN_ON(sk->sk_state != TCP_CLOSE);
 599         WARN_ON(!sock_flag(sk, SOCK_DEAD));
 600
 601         /* It cannot be in hash table! */
 602         WARN_ON(!sk_unhashed(sk));
 603
 604         /* If it has not 0 inet_sk(sk)->inet_num, it must be bound */
 605         WARN_ON(inet_sk(sk)->inet_num && !inet_csk(sk)->icsk_bind_hash);
 606
 607         sk->sk_prot->destroy(sk);
 608
 609         sk_stream_kill_queues(sk);
 610
 611         xfrm_sk_free_policy(sk);
 612
 613         sk_refcnt_debug_release(sk);
 614
 615         percpu_counter_dec(sk->sk_prot->orphan_count);
 616         sock_put(sk);
 617 }
 618 EXPORT_SYMBOL(inet_csk_destroy_sock);
 619
 620 int inet_csk_listen_start(struct sock *sk, const int nr_table_entries)
 621 {
 622         struct inet_sock *inet = inet_sk(sk);
 623         struct inet_connection_sock *icsk = inet_csk(sk);
 624         int rc = reqsk_queue_alloc(&icsk->icsk_accept_queue, nr_table_entries);
 625
 626         if (rc != 0)
 627                 return rc;
 628
 629         sk->sk_max_ack_backlog = 0;
 630         sk->sk_ack_backlog = 0;
 631         inet_csk_delack_init(sk);
 632
 633         /* There is race window here: we announce ourselves listening,
 634          * but this transition is still not validated by get_port().
 635          * It is OK, because this socket enters to hash table only
 636          * after validation is complete.
 637          */
 638         sk->sk_state = TCP_LISTEN;
 639         if (!sk->sk_prot->get_port(sk, inet->inet_num)) {
 640                 inet->inet_sport = htons(inet->inet_num);
 641
 642                 sk_dst_reset(sk);
 643                 sk->sk_prot->hash(sk);
 644
 645                 return 0;
 646         }
 647
 648         sk->sk_state = TCP_CLOSE;
 649         __reqsk_queue_destroy(&icsk->icsk_accept_queue);
 650         return -EADDRINUSE;
 651 }
 652 EXPORT_SYMBOL_GPL(inet_csk_listen_start);
 653
 654 /*
 655  *      This routine closes sockets which have been at least partially
 656  *      opened, but not yet accepted.
 657  */
 658 void inet_csk_listen_stop(struct sock *sk)
 659 {
 660         struct inet_connection_sock *icsk = inet_csk(sk);
 661         struct request_sock *acc_req;
 662         struct request_sock *req;
 663
 664         inet_csk_delete_keepalive_timer(sk);
 665
 666         /* make all the listen_opt local to us */
 667         acc_req = reqsk_queue_yank_acceptq(&icsk->icsk_accept_queue);
 668
 669         /* Following specs, it would be better either to send FIN
 670          * (and enter FIN-WAIT-1, it is normal close)
 671          * or to send active reset (abort).
 672          * Certainly, it is pretty dangerous while synflood, but it is
 673          * bad justification for our negligence 8)
 674          * To be honest, we are not able to make either
 675          * of the variants now.                 --ANK
 676          */
 677         reqsk_queue_destroy(&icsk->icsk_accept_queue);
 678
 679         while ((req = acc_req) != NULL) {
 680                 struct sock *child = req->sk;
 681
 682                 acc_req = req->dl_next;
 683
 684                 local_bh_disable();
 685                 bh_lock_sock(child);
 686                 WARN_ON(sock_owned_by_user(child));
 687                 sock_hold(child);
 688
 689                 sk->sk_prot->disconnect(child, O_NONBLOCK);
 690
 691                 sock_orphan(child);
 692
 693                 percpu_counter_inc(sk->sk_prot->orphan_count);
 694
 695                 inet_csk_destroy_sock(child);
 696
 697                 bh_unlock_sock(child);
 698                 local_bh_enable();
 699                 sock_put(child);
 700
 701                 sk_acceptq_removed(sk);
 702                 __reqsk_free(req);
 703         }
 704         WARN_ON(sk->sk_ack_backlog);
 705 }
 706 EXPORT_SYMBOL_GPL(inet_csk_listen_stop);
 707
 708 void inet_csk_addr2sockaddr(struct sock *sk, struct sockaddr *uaddr)
 709 {
 710         struct sockaddr_in *sin = (struct sockaddr_in *)uaddr;
 711         const struct inet_sock *inet = inet_sk(sk);
 712
 713         sin->sin_family         = AF_INET;
 714         sin->sin_addr.s_addr    = inet->inet_daddr;
 715         sin->sin_port           = inet->inet_dport;
 716 }
 717 EXPORT_SYMBOL_GPL(inet_csk_addr2sockaddr);
 718
 719 #ifdef CONFIG_COMPAT
 720 int inet_csk_compat_getsockopt(struct sock *sk, int level, int optname,
 721                                char __user *optval, int __user *optlen)
 722 {
 723         const struct inet_connection_sock *icsk = inet_csk(sk);
 724
 725         if (icsk->icsk_af_ops->compat_getsockopt != NULL)
 726                 return icsk->icsk_af_ops->compat_getsockopt(sk, level, optname,
 727                                                             optval, optlen);
 728         return icsk->icsk_af_ops->getsockopt(sk, level, optname,
 729                                              optval, optlen);
 730 }
 731 EXPORT_SYMBOL_GPL(inet_csk_compat_getsockopt);
 732
 733 int inet_csk_compat_setsockopt(struct sock *sk, int level, int optname,
 734                                char __user *optval, unsigned int optlen)
 735 {
 736         const struct inet_connection_sock *icsk = inet_csk(sk);
 737
 738         if (icsk->icsk_af_ops->compat_setsockopt != NULL)
 739                 return icsk->icsk_af_ops->compat_setsockopt(sk, level, optname,
 740                                                             optval, optlen);
 741         return icsk->icsk_af_ops->setsockopt(sk, level, optname,
 742                                              optval, optlen);
 743 }
 744 EXPORT_SYMBOL_GPL(inet_csk_compat_setsockopt);
 745 #endif