46b9c887bede0568ec378d3b809dda8fa463a166
[firefly-linux-kernel-4.4.55.git] / 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 #include <net/tcp.h>
27
28 #ifdef INET_CSK_DEBUG
29 const char inet_csk_timer_bug_msg[] = "inet_csk BUG: unknown timer value\n";
30 EXPORT_SYMBOL(inet_csk_timer_bug_msg);
31 #endif
32
33 void inet_get_local_port_range(struct net *net, int *low, int *high)
34 {
35         unsigned int seq;
36
37         do {
38                 seq = read_seqbegin(&net->ipv4.ip_local_ports.lock);
39
40                 *low = net->ipv4.ip_local_ports.range[0];
41                 *high = net->ipv4.ip_local_ports.range[1];
42         } while (read_seqretry(&net->ipv4.ip_local_ports.lock, seq));
43 }
44 EXPORT_SYMBOL(inet_get_local_port_range);
45
46 int inet_csk_bind_conflict(const struct sock *sk,
47                            const struct inet_bind_bucket *tb, bool relax)
48 {
49         struct sock *sk2;
50         int reuse = sk->sk_reuse;
51         int reuseport = sk->sk_reuseport;
52         kuid_t uid = sock_i_uid((struct sock *)sk);
53
54         /*
55          * Unlike other sk lookup places we do not check
56          * for sk_net here, since _all_ the socks listed
57          * in tb->owners list belong to the same net - the
58          * one this bucket belongs to.
59          */
60
61         sk_for_each_bound(sk2, &tb->owners) {
62                 if (sk != sk2 &&
63                     !inet_v6_ipv6only(sk2) &&
64                     (!sk->sk_bound_dev_if ||
65                      !sk2->sk_bound_dev_if ||
66                      sk->sk_bound_dev_if == sk2->sk_bound_dev_if)) {
67                         if ((!reuse || !sk2->sk_reuse ||
68                             sk2->sk_state == TCP_LISTEN) &&
69                             (!reuseport || !sk2->sk_reuseport ||
70                             (sk2->sk_state != TCP_TIME_WAIT &&
71                              !uid_eq(uid, sock_i_uid(sk2))))) {
72
73                                 if (!sk2->sk_rcv_saddr || !sk->sk_rcv_saddr ||
74                                     sk2->sk_rcv_saddr == sk->sk_rcv_saddr)
75                                         break;
76                         }
77                         if (!relax && reuse && sk2->sk_reuse &&
78                             sk2->sk_state != TCP_LISTEN) {
79
80                                 if (!sk2->sk_rcv_saddr || !sk->sk_rcv_saddr ||
81                                     sk2->sk_rcv_saddr == sk->sk_rcv_saddr)
82                                         break;
83                         }
84                 }
85         }
86         return sk2 != NULL;
87 }
88 EXPORT_SYMBOL_GPL(inet_csk_bind_conflict);
89
90 /* Obtain a reference to a local port for the given sock,
91  * if snum is zero it means select any available local port.
92  */
93 int inet_csk_get_port(struct sock *sk, unsigned short snum)
94 {
95         struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
96         struct inet_bind_hashbucket *head;
97         struct inet_bind_bucket *tb;
98         int ret, attempts = 5;
99         struct net *net = sock_net(sk);
100         int smallest_size = -1, smallest_rover;
101         kuid_t uid = sock_i_uid(sk);
102         int attempt_half = (sk->sk_reuse == SK_CAN_REUSE) ? 1 : 0;
103
104         local_bh_disable();
105         if (!snum) {
106                 int remaining, rover, low, high;
107
108 again:
109                 inet_get_local_port_range(net, &low, &high);
110                 if (attempt_half) {
111                         int half = low + ((high - low) >> 1);
112
113                         if (attempt_half == 1)
114                                 high = half;
115                         else
116                                 low = half;
117                 }
118                 remaining = (high - low) + 1;
119                 smallest_rover = rover = prandom_u32() % remaining + low;
120
121                 smallest_size = -1;
122                 do {
123                         if (inet_is_local_reserved_port(net, rover))
124                                 goto next_nolock;
125                         head = &hashinfo->bhash[inet_bhashfn(net, rover,
126                                         hashinfo->bhash_size)];
127                         spin_lock(&head->lock);
128                         inet_bind_bucket_for_each(tb, &head->chain)
129                                 if (net_eq(ib_net(tb), net) && tb->port == rover) {
130                                         if (((tb->fastreuse > 0 &&
131                                               sk->sk_reuse &&
132                                               sk->sk_state != TCP_LISTEN) ||
133                                              (tb->fastreuseport > 0 &&
134                                               sk->sk_reuseport &&
135                                               uid_eq(tb->fastuid, uid))) &&
136                                             (tb->num_owners < smallest_size || smallest_size == -1)) {
137                                                 smallest_size = tb->num_owners;
138                                                 smallest_rover = rover;
139                                         }
140                                         if (!inet_csk(sk)->icsk_af_ops->bind_conflict(sk, tb, false)) {
141                                                 snum = rover;
142                                                 goto tb_found;
143                                         }
144                                         goto next;
145                                 }
146                         break;
147                 next:
148                         spin_unlock(&head->lock);
149                 next_nolock:
150                         if (++rover > high)
151                                 rover = low;
152                 } while (--remaining > 0);
153
154                 /* Exhausted local port range during search?  It is not
155                  * possible for us to be holding one of the bind hash
156                  * locks if this test triggers, because if 'remaining'
157                  * drops to zero, we broke out of the do/while loop at
158                  * the top level, not from the 'break;' statement.
159                  */
160                 ret = 1;
161                 if (remaining <= 0) {
162                         if (smallest_size != -1) {
163                                 snum = smallest_rover;
164                                 goto have_snum;
165                         }
166                         if (attempt_half == 1) {
167                                 /* OK we now try the upper half of the range */
168                                 attempt_half = 2;
169                                 goto again;
170                         }
171                         goto fail;
172                 }
173                 /* OK, here is the one we will use.  HEAD is
174                  * non-NULL and we hold it's mutex.
175                  */
176                 snum = rover;
177         } else {
178 have_snum:
179                 head = &hashinfo->bhash[inet_bhashfn(net, snum,
180                                 hashinfo->bhash_size)];
181                 spin_lock(&head->lock);
182                 inet_bind_bucket_for_each(tb, &head->chain)
183                         if (net_eq(ib_net(tb), net) && tb->port == snum)
184                                 goto tb_found;
185         }
186         tb = NULL;
187         goto tb_not_found;
188 tb_found:
189         if (!hlist_empty(&tb->owners)) {
190                 if (sk->sk_reuse == SK_FORCE_REUSE)
191                         goto success;
192
193                 if (((tb->fastreuse > 0 &&
194                       sk->sk_reuse && sk->sk_state != TCP_LISTEN) ||
195                      (tb->fastreuseport > 0 &&
196                       sk->sk_reuseport && uid_eq(tb->fastuid, uid))) &&
197                     smallest_size == -1) {
198                         goto success;
199                 } else {
200                         ret = 1;
201                         if (inet_csk(sk)->icsk_af_ops->bind_conflict(sk, tb, true)) {
202                                 if (((sk->sk_reuse && sk->sk_state != TCP_LISTEN) ||
203                                      (tb->fastreuseport > 0 &&
204                                       sk->sk_reuseport && uid_eq(tb->fastuid, uid))) &&
205                                     smallest_size != -1 && --attempts >= 0) {
206                                         spin_unlock(&head->lock);
207                                         goto again;
208                                 }
209
210                                 goto fail_unlock;
211                         }
212                 }
213         }
214 tb_not_found:
215         ret = 1;
216         if (!tb && (tb = inet_bind_bucket_create(hashinfo->bind_bucket_cachep,
217                                         net, head, snum)) == NULL)
218                 goto fail_unlock;
219         if (hlist_empty(&tb->owners)) {
220                 if (sk->sk_reuse && sk->sk_state != TCP_LISTEN)
221                         tb->fastreuse = 1;
222                 else
223                         tb->fastreuse = 0;
224                 if (sk->sk_reuseport) {
225                         tb->fastreuseport = 1;
226                         tb->fastuid = uid;
227                 } else
228                         tb->fastreuseport = 0;
229         } else {
230                 if (tb->fastreuse &&
231                     (!sk->sk_reuse || sk->sk_state == TCP_LISTEN))
232                         tb->fastreuse = 0;
233                 if (tb->fastreuseport &&
234                     (!sk->sk_reuseport || !uid_eq(tb->fastuid, uid)))
235                         tb->fastreuseport = 0;
236         }
237 success:
238         if (!inet_csk(sk)->icsk_bind_hash)
239                 inet_bind_hash(sk, tb, snum);
240         WARN_ON(inet_csk(sk)->icsk_bind_hash != tb);
241         ret = 0;
242
243 fail_unlock:
244         spin_unlock(&head->lock);
245 fail:
246         local_bh_enable();
247         return ret;
248 }
249 EXPORT_SYMBOL_GPL(inet_csk_get_port);
250
251 /*
252  * Wait for an incoming connection, avoid race conditions. This must be called
253  * with the socket locked.
254  */
255 static int inet_csk_wait_for_connect(struct sock *sk, long timeo)
256 {
257         struct inet_connection_sock *icsk = inet_csk(sk);
258         DEFINE_WAIT(wait);
259         int err;
260
261         /*
262          * True wake-one mechanism for incoming connections: only
263          * one process gets woken up, not the 'whole herd'.
264          * Since we do not 'race & poll' for established sockets
265          * anymore, the common case will execute the loop only once.
266          *
267          * Subtle issue: "add_wait_queue_exclusive()" will be added
268          * after any current non-exclusive waiters, and we know that
269          * it will always _stay_ after any new non-exclusive waiters
270          * because all non-exclusive waiters are added at the
271          * beginning of the wait-queue. As such, it's ok to "drop"
272          * our exclusiveness temporarily when we get woken up without
273          * having to remove and re-insert us on the wait queue.
274          */
275         for (;;) {
276                 prepare_to_wait_exclusive(sk_sleep(sk), &wait,
277                                           TASK_INTERRUPTIBLE);
278                 release_sock(sk);
279                 if (reqsk_queue_empty(&icsk->icsk_accept_queue))
280                         timeo = schedule_timeout(timeo);
281                 sched_annotate_sleep();
282                 lock_sock(sk);
283                 err = 0;
284                 if (!reqsk_queue_empty(&icsk->icsk_accept_queue))
285                         break;
286                 err = -EINVAL;
287                 if (sk->sk_state != TCP_LISTEN)
288                         break;
289                 err = sock_intr_errno(timeo);
290                 if (signal_pending(current))
291                         break;
292                 err = -EAGAIN;
293                 if (!timeo)
294                         break;
295         }
296         finish_wait(sk_sleep(sk), &wait);
297         return err;
298 }
299
300 /*
301  * This will accept the next outstanding connection.
302  */
303 struct sock *inet_csk_accept(struct sock *sk, int flags, int *err)
304 {
305         struct inet_connection_sock *icsk = inet_csk(sk);
306         struct request_sock_queue *queue = &icsk->icsk_accept_queue;
307         struct request_sock *req;
308         struct sock *newsk;
309         int error;
310
311         lock_sock(sk);
312
313         /* We need to make sure that this socket is listening,
314          * and that it has something pending.
315          */
316         error = -EINVAL;
317         if (sk->sk_state != TCP_LISTEN)
318                 goto out_err;
319
320         /* Find already established connection */
321         if (reqsk_queue_empty(queue)) {
322                 long timeo = sock_rcvtimeo(sk, flags & O_NONBLOCK);
323
324                 /* If this is a non blocking socket don't sleep */
325                 error = -EAGAIN;
326                 if (!timeo)
327                         goto out_err;
328
329                 error = inet_csk_wait_for_connect(sk, timeo);
330                 if (error)
331                         goto out_err;
332         }
333         req = reqsk_queue_remove(queue, sk);
334         newsk = req->sk;
335
336         if (sk->sk_protocol == IPPROTO_TCP &&
337             tcp_rsk(req)->tfo_listener) {
338                 spin_lock_bh(&queue->fastopenq.lock);
339                 if (tcp_rsk(req)->tfo_listener) {
340                         /* We are still waiting for the final ACK from 3WHS
341                          * so can't free req now. Instead, we set req->sk to
342                          * NULL to signify that the child socket is taken
343                          * so reqsk_fastopen_remove() will free the req
344                          * when 3WHS finishes (or is aborted).
345                          */
346                         req->sk = NULL;
347                         req = NULL;
348                 }
349                 spin_unlock_bh(&queue->fastopenq.lock);
350         }
351 out:
352         release_sock(sk);
353         if (req)
354                 reqsk_put(req);
355         return newsk;
356 out_err:
357         newsk = NULL;
358         req = NULL;
359         *err = error;
360         goto out;
361 }
362 EXPORT_SYMBOL(inet_csk_accept);
363
364 /*
365  * Using different timers for retransmit, delayed acks and probes
366  * We may wish use just one timer maintaining a list of expire jiffies
367  * to optimize.
368  */
369 void inet_csk_init_xmit_timers(struct sock *sk,
370                                void (*retransmit_handler)(unsigned long),
371                                void (*delack_handler)(unsigned long),
372                                void (*keepalive_handler)(unsigned long))
373 {
374         struct inet_connection_sock *icsk = inet_csk(sk);
375
376         setup_timer(&icsk->icsk_retransmit_timer, retransmit_handler,
377                         (unsigned long)sk);
378         setup_timer(&icsk->icsk_delack_timer, delack_handler,
379                         (unsigned long)sk);
380         setup_timer(&sk->sk_timer, keepalive_handler, (unsigned long)sk);
381         icsk->icsk_pending = icsk->icsk_ack.pending = 0;
382 }
383 EXPORT_SYMBOL(inet_csk_init_xmit_timers);
384
385 void inet_csk_clear_xmit_timers(struct sock *sk)
386 {
387         struct inet_connection_sock *icsk = inet_csk(sk);
388
389         icsk->icsk_pending = icsk->icsk_ack.pending = icsk->icsk_ack.blocked = 0;
390
391         sk_stop_timer(sk, &icsk->icsk_retransmit_timer);
392         sk_stop_timer(sk, &icsk->icsk_delack_timer);
393         sk_stop_timer(sk, &sk->sk_timer);
394 }
395 EXPORT_SYMBOL(inet_csk_clear_xmit_timers);
396
397 void inet_csk_delete_keepalive_timer(struct sock *sk)
398 {
399         sk_stop_timer(sk, &sk->sk_timer);
400 }
401 EXPORT_SYMBOL(inet_csk_delete_keepalive_timer);
402
403 void inet_csk_reset_keepalive_timer(struct sock *sk, unsigned long len)
404 {
405         sk_reset_timer(sk, &sk->sk_timer, jiffies + len);
406 }
407 EXPORT_SYMBOL(inet_csk_reset_keepalive_timer);
408
409 struct dst_entry *inet_csk_route_req(const struct sock *sk,
410                                      struct flowi4 *fl4,
411                                      const struct request_sock *req)
412 {
413         const struct inet_request_sock *ireq = inet_rsk(req);
414         struct net *net = read_pnet(&ireq->ireq_net);
415         struct ip_options_rcu *opt = ireq->opt;
416         struct rtable *rt;
417
418         flowi4_init_output(fl4, ireq->ir_iif, ireq->ir_mark,
419                            RT_CONN_FLAGS(sk), RT_SCOPE_UNIVERSE,
420                            sk->sk_protocol, inet_sk_flowi_flags(sk),
421                            (opt && opt->opt.srr) ? opt->opt.faddr : ireq->ir_rmt_addr,
422                            ireq->ir_loc_addr, ireq->ir_rmt_port,
423                            htons(ireq->ir_num));
424         security_req_classify_flow(req, flowi4_to_flowi(fl4));
425         rt = ip_route_output_flow(net, fl4, sk);
426         if (IS_ERR(rt))
427                 goto no_route;
428         if (opt && opt->opt.is_strictroute && rt->rt_uses_gateway)
429                 goto route_err;
430         return &rt->dst;
431
432 route_err:
433         ip_rt_put(rt);
434 no_route:
435         IP_INC_STATS_BH(net, IPSTATS_MIB_OUTNOROUTES);
436         return NULL;
437 }
438 EXPORT_SYMBOL_GPL(inet_csk_route_req);
439
440 struct dst_entry *inet_csk_route_child_sock(const struct sock *sk,
441                                             struct sock *newsk,
442                                             const struct request_sock *req)
443 {
444         const struct inet_request_sock *ireq = inet_rsk(req);
445         struct net *net = read_pnet(&ireq->ireq_net);
446         struct inet_sock *newinet = inet_sk(newsk);
447         struct ip_options_rcu *opt;
448         struct flowi4 *fl4;
449         struct rtable *rt;
450
451         fl4 = &newinet->cork.fl.u.ip4;
452
453         rcu_read_lock();
454         opt = rcu_dereference(newinet->inet_opt);
455         flowi4_init_output(fl4, ireq->ir_iif, ireq->ir_mark,
456                            RT_CONN_FLAGS(sk), RT_SCOPE_UNIVERSE,
457                            sk->sk_protocol, inet_sk_flowi_flags(sk),
458                            (opt && opt->opt.srr) ? opt->opt.faddr : ireq->ir_rmt_addr,
459                            ireq->ir_loc_addr, ireq->ir_rmt_port,
460                            htons(ireq->ir_num));
461         security_req_classify_flow(req, flowi4_to_flowi(fl4));
462         rt = ip_route_output_flow(net, fl4, sk);
463         if (IS_ERR(rt))
464                 goto no_route;
465         if (opt && opt->opt.is_strictroute && rt->rt_uses_gateway)
466                 goto route_err;
467         rcu_read_unlock();
468         return &rt->dst;
469
470 route_err:
471         ip_rt_put(rt);
472 no_route:
473         rcu_read_unlock();
474         IP_INC_STATS_BH(net, IPSTATS_MIB_OUTNOROUTES);
475         return NULL;
476 }
477 EXPORT_SYMBOL_GPL(inet_csk_route_child_sock);
478
479 #if IS_ENABLED(CONFIG_IPV6)
480 #define AF_INET_FAMILY(fam) ((fam) == AF_INET)
481 #else
482 #define AF_INET_FAMILY(fam) true
483 #endif
484
485 /* Only thing we need from tcp.h */
486 extern int sysctl_tcp_synack_retries;
487
488
489 /* Decide when to expire the request and when to resend SYN-ACK */
490 static inline void syn_ack_recalc(struct request_sock *req, const int thresh,
491                                   const int max_retries,
492                                   const u8 rskq_defer_accept,
493                                   int *expire, int *resend)
494 {
495         if (!rskq_defer_accept) {
496                 *expire = req->num_timeout >= thresh;
497                 *resend = 1;
498                 return;
499         }
500         *expire = req->num_timeout >= thresh &&
501                   (!inet_rsk(req)->acked || req->num_timeout >= max_retries);
502         /*
503          * Do not resend while waiting for data after ACK,
504          * start to resend on end of deferring period to give
505          * last chance for data or ACK to create established socket.
506          */
507         *resend = !inet_rsk(req)->acked ||
508                   req->num_timeout >= rskq_defer_accept - 1;
509 }
510
511 int inet_rtx_syn_ack(const struct sock *parent, struct request_sock *req)
512 {
513         int err = req->rsk_ops->rtx_syn_ack(parent, req);
514
515         if (!err)
516                 req->num_retrans++;
517         return err;
518 }
519 EXPORT_SYMBOL(inet_rtx_syn_ack);
520
521 /* return true if req was found in the ehash table */
522 static bool reqsk_queue_unlink(struct request_sock_queue *queue,
523                                struct request_sock *req)
524 {
525         struct inet_hashinfo *hashinfo = req_to_sk(req)->sk_prot->h.hashinfo;
526         bool found = false;
527
528         if (sk_hashed(req_to_sk(req))) {
529                 spinlock_t *lock = inet_ehash_lockp(hashinfo, req->rsk_hash);
530
531                 spin_lock(lock);
532                 found = __sk_nulls_del_node_init_rcu(req_to_sk(req));
533                 spin_unlock(lock);
534         }
535         if (timer_pending(&req->rsk_timer) && del_timer_sync(&req->rsk_timer))
536                 reqsk_put(req);
537         return found;
538 }
539
540 void inet_csk_reqsk_queue_drop(struct sock *sk, struct request_sock *req)
541 {
542         if (reqsk_queue_unlink(&inet_csk(sk)->icsk_accept_queue, req)) {
543                 reqsk_queue_removed(&inet_csk(sk)->icsk_accept_queue, req);
544                 reqsk_put(req);
545         }
546 }
547 EXPORT_SYMBOL(inet_csk_reqsk_queue_drop);
548
549 void inet_csk_reqsk_queue_drop_and_put(struct sock *sk, struct request_sock *req)
550 {
551         inet_csk_reqsk_queue_drop(sk, req);
552         reqsk_put(req);
553 }
554 EXPORT_SYMBOL(inet_csk_reqsk_queue_drop_and_put);
555
556 static void reqsk_timer_handler(unsigned long data)
557 {
558         struct request_sock *req = (struct request_sock *)data;
559         struct sock *sk_listener = req->rsk_listener;
560         struct inet_connection_sock *icsk = inet_csk(sk_listener);
561         struct request_sock_queue *queue = &icsk->icsk_accept_queue;
562         int qlen, expire = 0, resend = 0;
563         int max_retries, thresh;
564         u8 defer_accept;
565
566         if (sk_state_load(sk_listener) != TCP_LISTEN)
567                 goto drop;
568
569         max_retries = icsk->icsk_syn_retries ? : sysctl_tcp_synack_retries;
570         thresh = max_retries;
571         /* Normally all the openreqs are young and become mature
572          * (i.e. converted to established socket) for first timeout.
573          * If synack was not acknowledged for 1 second, it means
574          * one of the following things: synack was lost, ack was lost,
575          * rtt is high or nobody planned to ack (i.e. synflood).
576          * When server is a bit loaded, queue is populated with old
577          * open requests, reducing effective size of queue.
578          * When server is well loaded, queue size reduces to zero
579          * after several minutes of work. It is not synflood,
580          * it is normal operation. The solution is pruning
581          * too old entries overriding normal timeout, when
582          * situation becomes dangerous.
583          *
584          * Essentially, we reserve half of room for young
585          * embrions; and abort old ones without pity, if old
586          * ones are about to clog our table.
587          */
588         qlen = reqsk_queue_len(queue);
589         if ((qlen << 1) > max(8U, sk_listener->sk_max_ack_backlog)) {
590                 int young = reqsk_queue_len_young(queue) << 1;
591
592                 while (thresh > 2) {
593                         if (qlen < young)
594                                 break;
595                         thresh--;
596                         young <<= 1;
597                 }
598         }
599         defer_accept = READ_ONCE(queue->rskq_defer_accept);
600         if (defer_accept)
601                 max_retries = defer_accept;
602         syn_ack_recalc(req, thresh, max_retries, defer_accept,
603                        &expire, &resend);
604         req->rsk_ops->syn_ack_timeout(req);
605         if (!expire &&
606             (!resend ||
607              !inet_rtx_syn_ack(sk_listener, req) ||
608              inet_rsk(req)->acked)) {
609                 unsigned long timeo;
610
611                 if (req->num_timeout++ == 0)
612                         atomic_dec(&queue->young);
613                 timeo = min(TCP_TIMEOUT_INIT << req->num_timeout, TCP_RTO_MAX);
614                 mod_timer_pinned(&req->rsk_timer, jiffies + timeo);
615                 return;
616         }
617 drop:
618         inet_csk_reqsk_queue_drop_and_put(sk_listener, req);
619 }
620
621 static void reqsk_queue_hash_req(struct request_sock *req,
622                                  unsigned long timeout)
623 {
624         req->num_retrans = 0;
625         req->num_timeout = 0;
626         req->sk = NULL;
627
628         setup_timer(&req->rsk_timer, reqsk_timer_handler, (unsigned long)req);
629         mod_timer_pinned(&req->rsk_timer, jiffies + timeout);
630
631         inet_ehash_insert(req_to_sk(req), NULL);
632         /* before letting lookups find us, make sure all req fields
633          * are committed to memory and refcnt initialized.
634          */
635         smp_wmb();
636         atomic_set(&req->rsk_refcnt, 2 + 1);
637 }
638
639 void inet_csk_reqsk_queue_hash_add(struct sock *sk, struct request_sock *req,
640                                    unsigned long timeout)
641 {
642         reqsk_queue_hash_req(req, timeout);
643         inet_csk_reqsk_queue_added(sk);
644 }
645 EXPORT_SYMBOL_GPL(inet_csk_reqsk_queue_hash_add);
646
647 /**
648  *      inet_csk_clone_lock - clone an inet socket, and lock its clone
649  *      @sk: the socket to clone
650  *      @req: request_sock
651  *      @priority: for allocation (%GFP_KERNEL, %GFP_ATOMIC, etc)
652  *
653  *      Caller must unlock socket even in error path (bh_unlock_sock(newsk))
654  */
655 struct sock *inet_csk_clone_lock(const struct sock *sk,
656                                  const struct request_sock *req,
657                                  const gfp_t priority)
658 {
659         struct sock *newsk = sk_clone_lock(sk, priority);
660
661         if (newsk) {
662                 struct inet_connection_sock *newicsk = inet_csk(newsk);
663
664                 newsk->sk_state = TCP_SYN_RECV;
665                 newicsk->icsk_bind_hash = NULL;
666
667                 inet_sk(newsk)->inet_dport = inet_rsk(req)->ir_rmt_port;
668                 inet_sk(newsk)->inet_num = inet_rsk(req)->ir_num;
669                 inet_sk(newsk)->inet_sport = htons(inet_rsk(req)->ir_num);
670                 newsk->sk_write_space = sk_stream_write_space;
671
672                 newsk->sk_mark = inet_rsk(req)->ir_mark;
673                 atomic64_set(&newsk->sk_cookie,
674                              atomic64_read(&inet_rsk(req)->ir_cookie));
675
676                 newicsk->icsk_retransmits = 0;
677                 newicsk->icsk_backoff     = 0;
678                 newicsk->icsk_probes_out  = 0;
679
680                 /* Deinitialize accept_queue to trap illegal accesses. */
681                 memset(&newicsk->icsk_accept_queue, 0, sizeof(newicsk->icsk_accept_queue));
682
683                 security_inet_csk_clone(newsk, req);
684         }
685         return newsk;
686 }
687 EXPORT_SYMBOL_GPL(inet_csk_clone_lock);
688
689 /*
690  * At this point, there should be no process reference to this
691  * socket, and thus no user references at all.  Therefore we
692  * can assume the socket waitqueue is inactive and nobody will
693  * try to jump onto it.
694  */
695 void inet_csk_destroy_sock(struct sock *sk)
696 {
697         WARN_ON(sk->sk_state != TCP_CLOSE);
698         WARN_ON(!sock_flag(sk, SOCK_DEAD));
699
700         /* It cannot be in hash table! */
701         WARN_ON(!sk_unhashed(sk));
702
703         /* If it has not 0 inet_sk(sk)->inet_num, it must be bound */
704         WARN_ON(inet_sk(sk)->inet_num && !inet_csk(sk)->icsk_bind_hash);
705
706         sk->sk_prot->destroy(sk);
707
708         sk_stream_kill_queues(sk);
709
710         xfrm_sk_free_policy(sk);
711
712         sk_refcnt_debug_release(sk);
713
714         percpu_counter_dec(sk->sk_prot->orphan_count);
715         sock_put(sk);
716 }
717 EXPORT_SYMBOL(inet_csk_destroy_sock);
718
719 /* This function allows to force a closure of a socket after the call to
720  * tcp/dccp_create_openreq_child().
721  */
722 void inet_csk_prepare_forced_close(struct sock *sk)
723         __releases(&sk->sk_lock.slock)
724 {
725         /* sk_clone_lock locked the socket and set refcnt to 2 */
726         bh_unlock_sock(sk);
727         sock_put(sk);
728
729         /* The below has to be done to allow calling inet_csk_destroy_sock */
730         sock_set_flag(sk, SOCK_DEAD);
731         percpu_counter_inc(sk->sk_prot->orphan_count);
732         inet_sk(sk)->inet_num = 0;
733 }
734 EXPORT_SYMBOL(inet_csk_prepare_forced_close);
735
736 int inet_csk_listen_start(struct sock *sk, int backlog)
737 {
738         struct inet_connection_sock *icsk = inet_csk(sk);
739         struct inet_sock *inet = inet_sk(sk);
740
741         reqsk_queue_alloc(&icsk->icsk_accept_queue);
742
743         sk->sk_max_ack_backlog = backlog;
744         sk->sk_ack_backlog = 0;
745         inet_csk_delack_init(sk);
746
747         /* There is race window here: we announce ourselves listening,
748          * but this transition is still not validated by get_port().
749          * It is OK, because this socket enters to hash table only
750          * after validation is complete.
751          */
752         sk_state_store(sk, TCP_LISTEN);
753         if (!sk->sk_prot->get_port(sk, inet->inet_num)) {
754                 inet->inet_sport = htons(inet->inet_num);
755
756                 sk_dst_reset(sk);
757                 sk->sk_prot->hash(sk);
758
759                 return 0;
760         }
761
762         sk->sk_state = TCP_CLOSE;
763         return -EADDRINUSE;
764 }
765 EXPORT_SYMBOL_GPL(inet_csk_listen_start);
766
767 static void inet_child_forget(struct sock *sk, struct request_sock *req,
768                               struct sock *child)
769 {
770         sk->sk_prot->disconnect(child, O_NONBLOCK);
771
772         sock_orphan(child);
773
774         percpu_counter_inc(sk->sk_prot->orphan_count);
775
776         if (sk->sk_protocol == IPPROTO_TCP && tcp_rsk(req)->tfo_listener) {
777                 BUG_ON(tcp_sk(child)->fastopen_rsk != req);
778                 BUG_ON(sk != req->rsk_listener);
779
780                 /* Paranoid, to prevent race condition if
781                  * an inbound pkt destined for child is
782                  * blocked by sock lock in tcp_v4_rcv().
783                  * Also to satisfy an assertion in
784                  * tcp_v4_destroy_sock().
785                  */
786                 tcp_sk(child)->fastopen_rsk = NULL;
787         }
788         inet_csk_destroy_sock(child);
789         reqsk_put(req);
790 }
791
792 void inet_csk_reqsk_queue_add(struct sock *sk, struct request_sock *req,
793                               struct sock *child)
794 {
795         struct request_sock_queue *queue = &inet_csk(sk)->icsk_accept_queue;
796
797         spin_lock(&queue->rskq_lock);
798         if (unlikely(sk->sk_state != TCP_LISTEN)) {
799                 inet_child_forget(sk, req, child);
800         } else {
801                 req->sk = child;
802                 req->dl_next = NULL;
803                 if (queue->rskq_accept_head == NULL)
804                         queue->rskq_accept_head = req;
805                 else
806                         queue->rskq_accept_tail->dl_next = req;
807                 queue->rskq_accept_tail = req;
808                 sk_acceptq_added(sk);
809         }
810         spin_unlock(&queue->rskq_lock);
811 }
812 EXPORT_SYMBOL(inet_csk_reqsk_queue_add);
813
814 struct sock *inet_csk_complete_hashdance(struct sock *sk, struct sock *child,
815                                          struct request_sock *req, bool own_req)
816 {
817         if (own_req) {
818                 inet_csk_reqsk_queue_drop(sk, req);
819                 reqsk_queue_removed(&inet_csk(sk)->icsk_accept_queue, req);
820                 inet_csk_reqsk_queue_add(sk, req, child);
821                 /* Warning: caller must not call reqsk_put(req);
822                  * child stole last reference on it.
823                  */
824                 return child;
825         }
826         /* Too bad, another child took ownership of the request, undo. */
827         bh_unlock_sock(child);
828         sock_put(child);
829         return NULL;
830 }
831 EXPORT_SYMBOL(inet_csk_complete_hashdance);
832
833 /*
834  *      This routine closes sockets which have been at least partially
835  *      opened, but not yet accepted.
836  */
837 void inet_csk_listen_stop(struct sock *sk)
838 {
839         struct inet_connection_sock *icsk = inet_csk(sk);
840         struct request_sock_queue *queue = &icsk->icsk_accept_queue;
841         struct request_sock *next, *req;
842
843         /* Following specs, it would be better either to send FIN
844          * (and enter FIN-WAIT-1, it is normal close)
845          * or to send active reset (abort).
846          * Certainly, it is pretty dangerous while synflood, but it is
847          * bad justification for our negligence 8)
848          * To be honest, we are not able to make either
849          * of the variants now.                 --ANK
850          */
851         while ((req = reqsk_queue_remove(queue, sk)) != NULL) {
852                 struct sock *child = req->sk;
853
854                 local_bh_disable();
855                 bh_lock_sock(child);
856                 WARN_ON(sock_owned_by_user(child));
857                 sock_hold(child);
858
859                 inet_child_forget(sk, req, child);
860                 bh_unlock_sock(child);
861                 local_bh_enable();
862                 sock_put(child);
863
864                 cond_resched();
865         }
866         if (queue->fastopenq.rskq_rst_head) {
867                 /* Free all the reqs queued in rskq_rst_head. */
868                 spin_lock_bh(&queue->fastopenq.lock);
869                 req = queue->fastopenq.rskq_rst_head;
870                 queue->fastopenq.rskq_rst_head = NULL;
871                 spin_unlock_bh(&queue->fastopenq.lock);
872                 while (req != NULL) {
873                         next = req->dl_next;
874                         reqsk_put(req);
875                         req = next;
876                 }
877         }
878         WARN_ON_ONCE(sk->sk_ack_backlog);
879 }
880 EXPORT_SYMBOL_GPL(inet_csk_listen_stop);
881
882 void inet_csk_addr2sockaddr(struct sock *sk, struct sockaddr *uaddr)
883 {
884         struct sockaddr_in *sin = (struct sockaddr_in *)uaddr;
885         const struct inet_sock *inet = inet_sk(sk);
886
887         sin->sin_family         = AF_INET;
888         sin->sin_addr.s_addr    = inet->inet_daddr;
889         sin->sin_port           = inet->inet_dport;
890 }
891 EXPORT_SYMBOL_GPL(inet_csk_addr2sockaddr);
892
893 #ifdef CONFIG_COMPAT
894 int inet_csk_compat_getsockopt(struct sock *sk, int level, int optname,
895                                char __user *optval, int __user *optlen)
896 {
897         const struct inet_connection_sock *icsk = inet_csk(sk);
898
899         if (icsk->icsk_af_ops->compat_getsockopt)
900                 return icsk->icsk_af_ops->compat_getsockopt(sk, level, optname,
901                                                             optval, optlen);
902         return icsk->icsk_af_ops->getsockopt(sk, level, optname,
903                                              optval, optlen);
904 }
905 EXPORT_SYMBOL_GPL(inet_csk_compat_getsockopt);
906
907 int inet_csk_compat_setsockopt(struct sock *sk, int level, int optname,
908                                char __user *optval, unsigned int optlen)
909 {
910         const struct inet_connection_sock *icsk = inet_csk(sk);
911
912         if (icsk->icsk_af_ops->compat_setsockopt)
913                 return icsk->icsk_af_ops->compat_setsockopt(sk, level, optname,
914                                                             optval, optlen);
915         return icsk->icsk_af_ops->setsockopt(sk, level, optname,
916                                              optval, optlen);
917 }
918 EXPORT_SYMBOL_GPL(inet_csk_compat_setsockopt);
919 #endif
920
921 static struct dst_entry *inet_csk_rebuild_route(struct sock *sk, struct flowi *fl)
922 {
923         const struct inet_sock *inet = inet_sk(sk);
924         const struct ip_options_rcu *inet_opt;
925         __be32 daddr = inet->inet_daddr;
926         struct flowi4 *fl4;
927         struct rtable *rt;
928
929         rcu_read_lock();
930         inet_opt = rcu_dereference(inet->inet_opt);
931         if (inet_opt && inet_opt->opt.srr)
932                 daddr = inet_opt->opt.faddr;
933         fl4 = &fl->u.ip4;
934         rt = ip_route_output_ports(sock_net(sk), fl4, sk, daddr,
935                                    inet->inet_saddr, inet->inet_dport,
936                                    inet->inet_sport, sk->sk_protocol,
937                                    RT_CONN_FLAGS(sk), sk->sk_bound_dev_if);
938         if (IS_ERR(rt))
939                 rt = NULL;
940         if (rt)
941                 sk_setup_caps(sk, &rt->dst);
942         rcu_read_unlock();
943
944         return &rt->dst;
945 }
946
947 struct dst_entry *inet_csk_update_pmtu(struct sock *sk, u32 mtu)
948 {
949         struct dst_entry *dst = __sk_dst_check(sk, 0);
950         struct inet_sock *inet = inet_sk(sk);
951
952         if (!dst) {
953                 dst = inet_csk_rebuild_route(sk, &inet->cork.fl);
954                 if (!dst)
955                         goto out;
956         }
957         dst->ops->update_pmtu(dst, sk, NULL, mtu);
958
959         dst = __sk_dst_check(sk, 0);
960         if (!dst)
961                 dst = inet_csk_rebuild_route(sk, &inet->cork.fl);
962 out:
963         return dst;
964 }
965 EXPORT_SYMBOL_GPL(inet_csk_update_pmtu);