1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * INET An implementation of the TCP/IP protocol suite for the LINUX
4 * operating system. INET is implemented using the BSD Socket
5 * interface as the means of communication with the user level.
7 * Support for INET connection oriented protocols.
9 * Authors: See the TCP sources
12 #include <linux/module.h>
13 #include <linux/jhash.h>
15 #include <net/inet_connection_sock.h>
16 #include <net/inet_hashtables.h>
17 #include <net/inet_timewait_sock.h>
19 #include <net/route.h>
20 #include <net/tcp_states.h>
23 #include <net/sock_reuseport.h>
24 #include <net/addrconf.h>
26 #if IS_ENABLED(CONFIG_IPV6)
27 /* match_sk*_wildcard == true: IPV6_ADDR_ANY equals to any IPv6 addresses
28 * if IPv6 only, and any IPv4 addresses
30 * match_sk*_wildcard == false: addresses must be exactly the same, i.e.
31 * IPV6_ADDR_ANY only equals to IPV6_ADDR_ANY,
32 * and 0.0.0.0 equals to 0.0.0.0 only
34 static bool ipv6_rcv_saddr_equal(const struct in6_addr *sk1_rcv_saddr6,
35 const struct in6_addr *sk2_rcv_saddr6,
36 __be32 sk1_rcv_saddr, __be32 sk2_rcv_saddr,
37 bool sk1_ipv6only, bool sk2_ipv6only,
38 bool match_sk1_wildcard,
39 bool match_sk2_wildcard)
41 int addr_type = ipv6_addr_type(sk1_rcv_saddr6);
42 int addr_type2 = sk2_rcv_saddr6 ? ipv6_addr_type(sk2_rcv_saddr6) : IPV6_ADDR_MAPPED;
44 /* if both are mapped, treat as IPv4 */
45 if (addr_type == IPV6_ADDR_MAPPED && addr_type2 == IPV6_ADDR_MAPPED) {
47 if (sk1_rcv_saddr == sk2_rcv_saddr)
49 return (match_sk1_wildcard && !sk1_rcv_saddr) ||
50 (match_sk2_wildcard && !sk2_rcv_saddr);
55 if (addr_type == IPV6_ADDR_ANY && addr_type2 == IPV6_ADDR_ANY)
58 if (addr_type2 == IPV6_ADDR_ANY && match_sk2_wildcard &&
59 !(sk2_ipv6only && addr_type == IPV6_ADDR_MAPPED))
62 if (addr_type == IPV6_ADDR_ANY && match_sk1_wildcard &&
63 !(sk1_ipv6only && addr_type2 == IPV6_ADDR_MAPPED))
67 ipv6_addr_equal(sk1_rcv_saddr6, sk2_rcv_saddr6))
74 /* match_sk*_wildcard == true: 0.0.0.0 equals to any IPv4 addresses
75 * match_sk*_wildcard == false: addresses must be exactly the same, i.e.
76 * 0.0.0.0 only equals to 0.0.0.0
78 static bool ipv4_rcv_saddr_equal(__be32 sk1_rcv_saddr, __be32 sk2_rcv_saddr,
79 bool sk2_ipv6only, bool match_sk1_wildcard,
80 bool match_sk2_wildcard)
83 if (sk1_rcv_saddr == sk2_rcv_saddr)
85 return (match_sk1_wildcard && !sk1_rcv_saddr) ||
86 (match_sk2_wildcard && !sk2_rcv_saddr);
91 bool inet_rcv_saddr_equal(const struct sock *sk, const struct sock *sk2,
94 #if IS_ENABLED(CONFIG_IPV6)
95 if (sk->sk_family == AF_INET6)
96 return ipv6_rcv_saddr_equal(&sk->sk_v6_rcv_saddr,
105 return ipv4_rcv_saddr_equal(sk->sk_rcv_saddr, sk2->sk_rcv_saddr,
106 ipv6_only_sock(sk2), match_wildcard,
109 EXPORT_SYMBOL(inet_rcv_saddr_equal);
111 bool inet_rcv_saddr_any(const struct sock *sk)
113 #if IS_ENABLED(CONFIG_IPV6)
114 if (sk->sk_family == AF_INET6)
115 return ipv6_addr_any(&sk->sk_v6_rcv_saddr);
117 return !sk->sk_rcv_saddr;
120 void inet_get_local_port_range(struct net *net, int *low, int *high)
125 seq = read_seqbegin(&net->ipv4.ip_local_ports.lock);
127 *low = net->ipv4.ip_local_ports.range[0];
128 *high = net->ipv4.ip_local_ports.range[1];
129 } while (read_seqretry(&net->ipv4.ip_local_ports.lock, seq));
131 EXPORT_SYMBOL(inet_get_local_port_range);
133 static int inet_csk_bind_conflict(const struct sock *sk,
134 const struct inet_bind_bucket *tb,
135 bool relax, bool reuseport_ok)
138 bool reuse = sk->sk_reuse;
139 bool reuseport = !!sk->sk_reuseport;
140 kuid_t uid = sock_i_uid((struct sock *)sk);
143 * Unlike other sk lookup places we do not check
144 * for sk_net here, since _all_ the socks listed
145 * in tb->owners list belong to the same net - the
146 * one this bucket belongs to.
149 sk_for_each_bound(sk2, &tb->owners) {
151 (!sk->sk_bound_dev_if ||
152 !sk2->sk_bound_dev_if ||
153 sk->sk_bound_dev_if == sk2->sk_bound_dev_if)) {
154 if (reuse && sk2->sk_reuse &&
155 sk2->sk_state != TCP_LISTEN) {
158 reuseport && sk2->sk_reuseport &&
159 !rcu_access_pointer(sk->sk_reuseport_cb) &&
160 (sk2->sk_state == TCP_TIME_WAIT ||
161 uid_eq(uid, sock_i_uid(sk2))))) &&
162 inet_rcv_saddr_equal(sk, sk2, true))
164 } else if (!reuseport_ok ||
165 !reuseport || !sk2->sk_reuseport ||
166 rcu_access_pointer(sk->sk_reuseport_cb) ||
167 (sk2->sk_state != TCP_TIME_WAIT &&
168 !uid_eq(uid, sock_i_uid(sk2)))) {
169 if (inet_rcv_saddr_equal(sk, sk2, true))
178 * Find an open port number for the socket. Returns with the
179 * inet_bind_hashbucket lock held.
181 static struct inet_bind_hashbucket *
182 inet_csk_find_open_port(struct sock *sk, struct inet_bind_bucket **tb_ret, int *port_ret)
184 struct inet_hashinfo *hinfo = sk->sk_prot->h.hashinfo;
186 struct inet_bind_hashbucket *head;
187 struct net *net = sock_net(sk);
189 int i, low, high, attempt_half;
190 struct inet_bind_bucket *tb;
191 u32 remaining, offset;
194 l3mdev = inet_sk_bound_l3mdev(sk);
196 attempt_half = (sk->sk_reuse == SK_CAN_REUSE) ? 1 : 0;
198 inet_get_local_port_range(net, &low, &high);
199 high++; /* [32768, 60999] -> [32768, 61000[ */
203 int half = low + (((high - low) >> 2) << 1);
205 if (attempt_half == 1)
210 remaining = high - low;
211 if (likely(remaining > 1))
214 offset = prandom_u32() % remaining;
215 /* __inet_hash_connect() favors ports having @low parity
216 * We do the opposite to not pollute connect() users.
222 for (i = 0; i < remaining; i += 2, port += 2) {
223 if (unlikely(port >= high))
225 if (inet_is_local_reserved_port(net, port))
227 head = &hinfo->bhash[inet_bhashfn(net, port,
229 spin_lock_bh(&head->lock);
230 inet_bind_bucket_for_each(tb, &head->chain)
231 if (net_eq(ib_net(tb), net) && tb->l3mdev == l3mdev &&
233 if (!inet_csk_bind_conflict(sk, tb, relax, false))
240 spin_unlock_bh(&head->lock);
246 goto other_parity_scan;
248 if (attempt_half == 1) {
249 /* OK we now try the upper half of the range */
251 goto other_half_scan;
254 if (net->ipv4.sysctl_ip_autobind_reuse && !relax) {
255 /* We still have a chance to connect to different destinations */
257 goto ports_exhausted;
266 static inline int sk_reuseport_match(struct inet_bind_bucket *tb,
269 kuid_t uid = sock_i_uid(sk);
271 if (tb->fastreuseport <= 0)
273 if (!sk->sk_reuseport)
275 if (rcu_access_pointer(sk->sk_reuseport_cb))
277 if (!uid_eq(tb->fastuid, uid))
279 /* We only need to check the rcv_saddr if this tb was once marked
280 * without fastreuseport and then was reset, as we can only know that
281 * the fast_*rcv_saddr doesn't have any conflicts with the socks on the
284 if (tb->fastreuseport == FASTREUSEPORT_ANY)
286 #if IS_ENABLED(CONFIG_IPV6)
287 if (tb->fast_sk_family == AF_INET6)
288 return ipv6_rcv_saddr_equal(&tb->fast_v6_rcv_saddr,
293 ipv6_only_sock(sk), true, false);
295 return ipv4_rcv_saddr_equal(tb->fast_rcv_saddr, sk->sk_rcv_saddr,
296 ipv6_only_sock(sk), true, false);
299 /* Obtain a reference to a local port for the given sock,
300 * if snum is zero it means select any available local port.
301 * We try to allocate an odd port (and leave even ports for connect())
303 int inet_csk_get_port(struct sock *sk, unsigned short snum)
305 bool reuse = sk->sk_reuse && sk->sk_state != TCP_LISTEN;
306 struct inet_hashinfo *hinfo = sk->sk_prot->h.hashinfo;
307 int ret = 1, port = snum;
308 struct inet_bind_hashbucket *head;
309 struct net *net = sock_net(sk);
310 struct inet_bind_bucket *tb = NULL;
311 kuid_t uid = sock_i_uid(sk);
314 l3mdev = inet_sk_bound_l3mdev(sk);
317 head = inet_csk_find_open_port(sk, &tb, &port);
324 head = &hinfo->bhash[inet_bhashfn(net, port,
326 spin_lock_bh(&head->lock);
327 inet_bind_bucket_for_each(tb, &head->chain)
328 if (net_eq(ib_net(tb), net) && tb->l3mdev == l3mdev &&
332 tb = inet_bind_bucket_create(hinfo->bind_bucket_cachep,
333 net, head, port, l3mdev);
337 if (!hlist_empty(&tb->owners)) {
338 if (sk->sk_reuse == SK_FORCE_REUSE)
341 if ((tb->fastreuse > 0 && reuse) ||
342 sk_reuseport_match(tb, sk))
344 if (inet_csk_bind_conflict(sk, tb, true, true))
348 if (hlist_empty(&tb->owners)) {
349 tb->fastreuse = reuse;
350 if (sk->sk_reuseport) {
351 tb->fastreuseport = FASTREUSEPORT_ANY;
353 tb->fast_rcv_saddr = sk->sk_rcv_saddr;
354 tb->fast_ipv6_only = ipv6_only_sock(sk);
355 tb->fast_sk_family = sk->sk_family;
356 #if IS_ENABLED(CONFIG_IPV6)
357 tb->fast_v6_rcv_saddr = sk->sk_v6_rcv_saddr;
360 tb->fastreuseport = 0;
365 if (sk->sk_reuseport) {
366 /* We didn't match or we don't have fastreuseport set on
367 * the tb, but we have sk_reuseport set on this socket
368 * and we know that there are no bind conflicts with
369 * this socket in this tb, so reset our tb's reuseport
370 * settings so that any subsequent sockets that match
371 * our current socket will be put on the fast path.
373 * If we reset we need to set FASTREUSEPORT_STRICT so we
374 * do extra checking for all subsequent sk_reuseport
377 if (!sk_reuseport_match(tb, sk)) {
378 tb->fastreuseport = FASTREUSEPORT_STRICT;
380 tb->fast_rcv_saddr = sk->sk_rcv_saddr;
381 tb->fast_ipv6_only = ipv6_only_sock(sk);
382 tb->fast_sk_family = sk->sk_family;
383 #if IS_ENABLED(CONFIG_IPV6)
384 tb->fast_v6_rcv_saddr = sk->sk_v6_rcv_saddr;
388 tb->fastreuseport = 0;
391 if (!inet_csk(sk)->icsk_bind_hash)
392 inet_bind_hash(sk, tb, port);
393 WARN_ON(inet_csk(sk)->icsk_bind_hash != tb);
397 spin_unlock_bh(&head->lock);
400 EXPORT_SYMBOL_GPL(inet_csk_get_port);
403 * Wait for an incoming connection, avoid race conditions. This must be called
404 * with the socket locked.
406 static int inet_csk_wait_for_connect(struct sock *sk, long timeo)
408 struct inet_connection_sock *icsk = inet_csk(sk);
413 * True wake-one mechanism for incoming connections: only
414 * one process gets woken up, not the 'whole herd'.
415 * Since we do not 'race & poll' for established sockets
416 * anymore, the common case will execute the loop only once.
418 * Subtle issue: "add_wait_queue_exclusive()" will be added
419 * after any current non-exclusive waiters, and we know that
420 * it will always _stay_ after any new non-exclusive waiters
421 * because all non-exclusive waiters are added at the
422 * beginning of the wait-queue. As such, it's ok to "drop"
423 * our exclusiveness temporarily when we get woken up without
424 * having to remove and re-insert us on the wait queue.
427 prepare_to_wait_exclusive(sk_sleep(sk), &wait,
430 if (reqsk_queue_empty(&icsk->icsk_accept_queue))
431 timeo = schedule_timeout(timeo);
432 sched_annotate_sleep();
435 if (!reqsk_queue_empty(&icsk->icsk_accept_queue))
438 if (sk->sk_state != TCP_LISTEN)
440 err = sock_intr_errno(timeo);
441 if (signal_pending(current))
447 finish_wait(sk_sleep(sk), &wait);
452 * This will accept the next outstanding connection.
454 struct sock *inet_csk_accept(struct sock *sk, int flags, int *err, bool kern)
456 struct inet_connection_sock *icsk = inet_csk(sk);
457 struct request_sock_queue *queue = &icsk->icsk_accept_queue;
458 struct request_sock *req;
464 /* We need to make sure that this socket is listening,
465 * and that it has something pending.
468 if (sk->sk_state != TCP_LISTEN)
471 /* Find already established connection */
472 if (reqsk_queue_empty(queue)) {
473 long timeo = sock_rcvtimeo(sk, flags & O_NONBLOCK);
475 /* If this is a non blocking socket don't sleep */
480 error = inet_csk_wait_for_connect(sk, timeo);
484 req = reqsk_queue_remove(queue, sk);
487 if (sk->sk_protocol == IPPROTO_TCP &&
488 tcp_rsk(req)->tfo_listener) {
489 spin_lock_bh(&queue->fastopenq.lock);
490 if (tcp_rsk(req)->tfo_listener) {
491 /* We are still waiting for the final ACK from 3WHS
492 * so can't free req now. Instead, we set req->sk to
493 * NULL to signify that the child socket is taken
494 * so reqsk_fastopen_remove() will free the req
495 * when 3WHS finishes (or is aborted).
500 spin_unlock_bh(&queue->fastopenq.lock);
505 if (newsk && mem_cgroup_sockets_enabled) {
508 /* atomically get the memory usage, set and charge the
513 /* The socket has not been accepted yet, no need to look at
514 * newsk->sk_wmem_queued.
516 amt = sk_mem_pages(newsk->sk_forward_alloc +
517 atomic_read(&newsk->sk_rmem_alloc));
518 mem_cgroup_sk_alloc(newsk);
519 if (newsk->sk_memcg && amt)
520 mem_cgroup_charge_skmem(newsk->sk_memcg, amt);
533 EXPORT_SYMBOL(inet_csk_accept);
536 * Using different timers for retransmit, delayed acks and probes
537 * We may wish use just one timer maintaining a list of expire jiffies
540 void inet_csk_init_xmit_timers(struct sock *sk,
541 void (*retransmit_handler)(struct timer_list *t),
542 void (*delack_handler)(struct timer_list *t),
543 void (*keepalive_handler)(struct timer_list *t))
545 struct inet_connection_sock *icsk = inet_csk(sk);
547 timer_setup(&icsk->icsk_retransmit_timer, retransmit_handler, 0);
548 timer_setup(&icsk->icsk_delack_timer, delack_handler, 0);
549 timer_setup(&sk->sk_timer, keepalive_handler, 0);
550 icsk->icsk_pending = icsk->icsk_ack.pending = 0;
552 EXPORT_SYMBOL(inet_csk_init_xmit_timers);
554 void inet_csk_clear_xmit_timers(struct sock *sk)
556 struct inet_connection_sock *icsk = inet_csk(sk);
558 icsk->icsk_pending = icsk->icsk_ack.pending = icsk->icsk_ack.blocked = 0;
560 sk_stop_timer(sk, &icsk->icsk_retransmit_timer);
561 sk_stop_timer(sk, &icsk->icsk_delack_timer);
562 sk_stop_timer(sk, &sk->sk_timer);
564 EXPORT_SYMBOL(inet_csk_clear_xmit_timers);
566 void inet_csk_delete_keepalive_timer(struct sock *sk)
568 sk_stop_timer(sk, &sk->sk_timer);
570 EXPORT_SYMBOL(inet_csk_delete_keepalive_timer);
572 void inet_csk_reset_keepalive_timer(struct sock *sk, unsigned long len)
574 sk_reset_timer(sk, &sk->sk_timer, jiffies + len);
576 EXPORT_SYMBOL(inet_csk_reset_keepalive_timer);
578 struct dst_entry *inet_csk_route_req(const struct sock *sk,
580 const struct request_sock *req)
582 const struct inet_request_sock *ireq = inet_rsk(req);
583 struct net *net = read_pnet(&ireq->ireq_net);
584 struct ip_options_rcu *opt;
588 opt = rcu_dereference(ireq->ireq_opt);
590 flowi4_init_output(fl4, ireq->ir_iif, ireq->ir_mark,
591 RT_CONN_FLAGS(sk), RT_SCOPE_UNIVERSE,
592 sk->sk_protocol, inet_sk_flowi_flags(sk),
593 (opt && opt->opt.srr) ? opt->opt.faddr : ireq->ir_rmt_addr,
594 ireq->ir_loc_addr, ireq->ir_rmt_port,
595 htons(ireq->ir_num), sk->sk_uid);
596 security_req_classify_flow(req, flowi4_to_flowi(fl4));
597 rt = ip_route_output_flow(net, fl4, sk);
600 if (opt && opt->opt.is_strictroute && rt->rt_uses_gateway)
609 __IP_INC_STATS(net, IPSTATS_MIB_OUTNOROUTES);
612 EXPORT_SYMBOL_GPL(inet_csk_route_req);
614 struct dst_entry *inet_csk_route_child_sock(const struct sock *sk,
616 const struct request_sock *req)
618 const struct inet_request_sock *ireq = inet_rsk(req);
619 struct net *net = read_pnet(&ireq->ireq_net);
620 struct inet_sock *newinet = inet_sk(newsk);
621 struct ip_options_rcu *opt;
625 opt = rcu_dereference(ireq->ireq_opt);
626 fl4 = &newinet->cork.fl.u.ip4;
628 flowi4_init_output(fl4, ireq->ir_iif, ireq->ir_mark,
629 RT_CONN_FLAGS(sk), RT_SCOPE_UNIVERSE,
630 sk->sk_protocol, inet_sk_flowi_flags(sk),
631 (opt && opt->opt.srr) ? opt->opt.faddr : ireq->ir_rmt_addr,
632 ireq->ir_loc_addr, ireq->ir_rmt_port,
633 htons(ireq->ir_num), sk->sk_uid);
634 security_req_classify_flow(req, flowi4_to_flowi(fl4));
635 rt = ip_route_output_flow(net, fl4, sk);
638 if (opt && opt->opt.is_strictroute && rt->rt_uses_gateway)
645 __IP_INC_STATS(net, IPSTATS_MIB_OUTNOROUTES);
648 EXPORT_SYMBOL_GPL(inet_csk_route_child_sock);
650 /* Decide when to expire the request and when to resend SYN-ACK */
651 static inline void syn_ack_recalc(struct request_sock *req, const int thresh,
652 const int max_retries,
653 const u8 rskq_defer_accept,
654 int *expire, int *resend)
656 if (!rskq_defer_accept) {
657 *expire = req->num_timeout >= thresh;
661 *expire = req->num_timeout >= thresh &&
662 (!inet_rsk(req)->acked || req->num_timeout >= max_retries);
664 * Do not resend while waiting for data after ACK,
665 * start to resend on end of deferring period to give
666 * last chance for data or ACK to create established socket.
668 *resend = !inet_rsk(req)->acked ||
669 req->num_timeout >= rskq_defer_accept - 1;
672 int inet_rtx_syn_ack(const struct sock *parent, struct request_sock *req)
674 int err = req->rsk_ops->rtx_syn_ack(parent, req);
680 EXPORT_SYMBOL(inet_rtx_syn_ack);
682 /* return true if req was found in the ehash table */
683 static bool reqsk_queue_unlink(struct request_sock *req)
685 struct inet_hashinfo *hashinfo = req_to_sk(req)->sk_prot->h.hashinfo;
688 if (sk_hashed(req_to_sk(req))) {
689 spinlock_t *lock = inet_ehash_lockp(hashinfo, req->rsk_hash);
692 found = __sk_nulls_del_node_init_rcu(req_to_sk(req));
695 if (timer_pending(&req->rsk_timer) && del_timer_sync(&req->rsk_timer))
700 void inet_csk_reqsk_queue_drop(struct sock *sk, struct request_sock *req)
702 if (reqsk_queue_unlink(req)) {
703 reqsk_queue_removed(&inet_csk(sk)->icsk_accept_queue, req);
707 EXPORT_SYMBOL(inet_csk_reqsk_queue_drop);
709 void inet_csk_reqsk_queue_drop_and_put(struct sock *sk, struct request_sock *req)
711 inet_csk_reqsk_queue_drop(sk, req);
714 EXPORT_SYMBOL(inet_csk_reqsk_queue_drop_and_put);
716 static void reqsk_timer_handler(struct timer_list *t)
718 struct request_sock *req = from_timer(req, t, rsk_timer);
719 struct sock *sk_listener = req->rsk_listener;
720 struct net *net = sock_net(sk_listener);
721 struct inet_connection_sock *icsk = inet_csk(sk_listener);
722 struct request_sock_queue *queue = &icsk->icsk_accept_queue;
723 int qlen, expire = 0, resend = 0;
724 int max_retries, thresh;
727 if (inet_sk_state_load(sk_listener) != TCP_LISTEN)
730 max_retries = icsk->icsk_syn_retries ? : net->ipv4.sysctl_tcp_synack_retries;
731 thresh = max_retries;
732 /* Normally all the openreqs are young and become mature
733 * (i.e. converted to established socket) for first timeout.
734 * If synack was not acknowledged for 1 second, it means
735 * one of the following things: synack was lost, ack was lost,
736 * rtt is high or nobody planned to ack (i.e. synflood).
737 * When server is a bit loaded, queue is populated with old
738 * open requests, reducing effective size of queue.
739 * When server is well loaded, queue size reduces to zero
740 * after several minutes of work. It is not synflood,
741 * it is normal operation. The solution is pruning
742 * too old entries overriding normal timeout, when
743 * situation becomes dangerous.
745 * Essentially, we reserve half of room for young
746 * embrions; and abort old ones without pity, if old
747 * ones are about to clog our table.
749 qlen = reqsk_queue_len(queue);
750 if ((qlen << 1) > max(8U, READ_ONCE(sk_listener->sk_max_ack_backlog))) {
751 int young = reqsk_queue_len_young(queue) << 1;
760 defer_accept = READ_ONCE(queue->rskq_defer_accept);
762 max_retries = defer_accept;
763 syn_ack_recalc(req, thresh, max_retries, defer_accept,
765 req->rsk_ops->syn_ack_timeout(req);
768 !inet_rtx_syn_ack(sk_listener, req) ||
769 inet_rsk(req)->acked)) {
772 if (req->num_timeout++ == 0)
773 atomic_dec(&queue->young);
774 timeo = min(TCP_TIMEOUT_INIT << req->num_timeout, TCP_RTO_MAX);
775 mod_timer(&req->rsk_timer, jiffies + timeo);
779 inet_csk_reqsk_queue_drop_and_put(sk_listener, req);
782 static void reqsk_queue_hash_req(struct request_sock *req,
783 unsigned long timeout)
785 timer_setup(&req->rsk_timer, reqsk_timer_handler, TIMER_PINNED);
786 mod_timer(&req->rsk_timer, jiffies + timeout);
788 inet_ehash_insert(req_to_sk(req), NULL);
789 /* before letting lookups find us, make sure all req fields
790 * are committed to memory and refcnt initialized.
793 refcount_set(&req->rsk_refcnt, 2 + 1);
796 void inet_csk_reqsk_queue_hash_add(struct sock *sk, struct request_sock *req,
797 unsigned long timeout)
799 reqsk_queue_hash_req(req, timeout);
800 inet_csk_reqsk_queue_added(sk);
802 EXPORT_SYMBOL_GPL(inet_csk_reqsk_queue_hash_add);
804 static void inet_clone_ulp(const struct request_sock *req, struct sock *newsk,
805 const gfp_t priority)
807 struct inet_connection_sock *icsk = inet_csk(newsk);
809 if (!icsk->icsk_ulp_ops)
812 if (icsk->icsk_ulp_ops->clone)
813 icsk->icsk_ulp_ops->clone(req, newsk, priority);
817 * inet_csk_clone_lock - clone an inet socket, and lock its clone
818 * @sk: the socket to clone
820 * @priority: for allocation (%GFP_KERNEL, %GFP_ATOMIC, etc)
822 * Caller must unlock socket even in error path (bh_unlock_sock(newsk))
824 struct sock *inet_csk_clone_lock(const struct sock *sk,
825 const struct request_sock *req,
826 const gfp_t priority)
828 struct sock *newsk = sk_clone_lock(sk, priority);
831 struct inet_connection_sock *newicsk = inet_csk(newsk);
833 inet_sk_set_state(newsk, TCP_SYN_RECV);
834 newicsk->icsk_bind_hash = NULL;
836 inet_sk(newsk)->inet_dport = inet_rsk(req)->ir_rmt_port;
837 inet_sk(newsk)->inet_num = inet_rsk(req)->ir_num;
838 inet_sk(newsk)->inet_sport = htons(inet_rsk(req)->ir_num);
840 /* listeners have SOCK_RCU_FREE, not the children */
841 sock_reset_flag(newsk, SOCK_RCU_FREE);
843 inet_sk(newsk)->mc_list = NULL;
845 newsk->sk_mark = inet_rsk(req)->ir_mark;
846 atomic64_set(&newsk->sk_cookie,
847 atomic64_read(&inet_rsk(req)->ir_cookie));
849 newicsk->icsk_retransmits = 0;
850 newicsk->icsk_backoff = 0;
851 newicsk->icsk_probes_out = 0;
853 /* Deinitialize accept_queue to trap illegal accesses. */
854 memset(&newicsk->icsk_accept_queue, 0, sizeof(newicsk->icsk_accept_queue));
856 inet_clone_ulp(req, newsk, priority);
858 security_inet_csk_clone(newsk, req);
862 EXPORT_SYMBOL_GPL(inet_csk_clone_lock);
865 * At this point, there should be no process reference to this
866 * socket, and thus no user references at all. Therefore we
867 * can assume the socket waitqueue is inactive and nobody will
868 * try to jump onto it.
870 void inet_csk_destroy_sock(struct sock *sk)
872 WARN_ON(sk->sk_state != TCP_CLOSE);
873 WARN_ON(!sock_flag(sk, SOCK_DEAD));
875 /* It cannot be in hash table! */
876 WARN_ON(!sk_unhashed(sk));
878 /* If it has not 0 inet_sk(sk)->inet_num, it must be bound */
879 WARN_ON(inet_sk(sk)->inet_num && !inet_csk(sk)->icsk_bind_hash);
881 sk->sk_prot->destroy(sk);
883 sk_stream_kill_queues(sk);
885 xfrm_sk_free_policy(sk);
887 sk_refcnt_debug_release(sk);
889 percpu_counter_dec(sk->sk_prot->orphan_count);
893 EXPORT_SYMBOL(inet_csk_destroy_sock);
895 /* This function allows to force a closure of a socket after the call to
896 * tcp/dccp_create_openreq_child().
898 void inet_csk_prepare_forced_close(struct sock *sk)
899 __releases(&sk->sk_lock.slock)
901 /* sk_clone_lock locked the socket and set refcnt to 2 */
904 inet_csk_prepare_for_destroy_sock(sk);
905 inet_sk(sk)->inet_num = 0;
907 EXPORT_SYMBOL(inet_csk_prepare_forced_close);
909 int inet_csk_listen_start(struct sock *sk, int backlog)
911 struct inet_connection_sock *icsk = inet_csk(sk);
912 struct inet_sock *inet = inet_sk(sk);
913 int err = -EADDRINUSE;
915 reqsk_queue_alloc(&icsk->icsk_accept_queue);
917 sk->sk_ack_backlog = 0;
918 inet_csk_delack_init(sk);
920 /* There is race window here: we announce ourselves listening,
921 * but this transition is still not validated by get_port().
922 * It is OK, because this socket enters to hash table only
923 * after validation is complete.
925 inet_sk_state_store(sk, TCP_LISTEN);
926 if (!sk->sk_prot->get_port(sk, inet->inet_num)) {
927 inet->inet_sport = htons(inet->inet_num);
930 err = sk->sk_prot->hash(sk);
936 inet_sk_set_state(sk, TCP_CLOSE);
939 EXPORT_SYMBOL_GPL(inet_csk_listen_start);
941 static void inet_child_forget(struct sock *sk, struct request_sock *req,
944 sk->sk_prot->disconnect(child, O_NONBLOCK);
948 percpu_counter_inc(sk->sk_prot->orphan_count);
950 if (sk->sk_protocol == IPPROTO_TCP && tcp_rsk(req)->tfo_listener) {
951 BUG_ON(rcu_access_pointer(tcp_sk(child)->fastopen_rsk) != req);
952 BUG_ON(sk != req->rsk_listener);
954 /* Paranoid, to prevent race condition if
955 * an inbound pkt destined for child is
956 * blocked by sock lock in tcp_v4_rcv().
957 * Also to satisfy an assertion in
958 * tcp_v4_destroy_sock().
960 RCU_INIT_POINTER(tcp_sk(child)->fastopen_rsk, NULL);
962 inet_csk_destroy_sock(child);
965 struct sock *inet_csk_reqsk_queue_add(struct sock *sk,
966 struct request_sock *req,
969 struct request_sock_queue *queue = &inet_csk(sk)->icsk_accept_queue;
971 spin_lock(&queue->rskq_lock);
972 if (unlikely(sk->sk_state != TCP_LISTEN)) {
973 inet_child_forget(sk, req, child);
978 if (queue->rskq_accept_head == NULL)
979 WRITE_ONCE(queue->rskq_accept_head, req);
981 queue->rskq_accept_tail->dl_next = req;
982 queue->rskq_accept_tail = req;
983 sk_acceptq_added(sk);
985 spin_unlock(&queue->rskq_lock);
988 EXPORT_SYMBOL(inet_csk_reqsk_queue_add);
990 struct sock *inet_csk_complete_hashdance(struct sock *sk, struct sock *child,
991 struct request_sock *req, bool own_req)
994 inet_csk_reqsk_queue_drop(sk, req);
995 reqsk_queue_removed(&inet_csk(sk)->icsk_accept_queue, req);
996 if (inet_csk_reqsk_queue_add(sk, req, child))
999 /* Too bad, another child took ownership of the request, undo. */
1000 bh_unlock_sock(child);
1004 EXPORT_SYMBOL(inet_csk_complete_hashdance);
1007 * This routine closes sockets which have been at least partially
1008 * opened, but not yet accepted.
1010 void inet_csk_listen_stop(struct sock *sk)
1012 struct inet_connection_sock *icsk = inet_csk(sk);
1013 struct request_sock_queue *queue = &icsk->icsk_accept_queue;
1014 struct request_sock *next, *req;
1016 /* Following specs, it would be better either to send FIN
1017 * (and enter FIN-WAIT-1, it is normal close)
1018 * or to send active reset (abort).
1019 * Certainly, it is pretty dangerous while synflood, but it is
1020 * bad justification for our negligence 8)
1021 * To be honest, we are not able to make either
1022 * of the variants now. --ANK
1024 while ((req = reqsk_queue_remove(queue, sk)) != NULL) {
1025 struct sock *child = req->sk;
1028 bh_lock_sock(child);
1029 WARN_ON(sock_owned_by_user(child));
1032 inet_child_forget(sk, req, child);
1034 bh_unlock_sock(child);
1040 if (queue->fastopenq.rskq_rst_head) {
1041 /* Free all the reqs queued in rskq_rst_head. */
1042 spin_lock_bh(&queue->fastopenq.lock);
1043 req = queue->fastopenq.rskq_rst_head;
1044 queue->fastopenq.rskq_rst_head = NULL;
1045 spin_unlock_bh(&queue->fastopenq.lock);
1046 while (req != NULL) {
1047 next = req->dl_next;
1052 WARN_ON_ONCE(sk->sk_ack_backlog);
1054 EXPORT_SYMBOL_GPL(inet_csk_listen_stop);
1056 void inet_csk_addr2sockaddr(struct sock *sk, struct sockaddr *uaddr)
1058 struct sockaddr_in *sin = (struct sockaddr_in *)uaddr;
1059 const struct inet_sock *inet = inet_sk(sk);
1061 sin->sin_family = AF_INET;
1062 sin->sin_addr.s_addr = inet->inet_daddr;
1063 sin->sin_port = inet->inet_dport;
1065 EXPORT_SYMBOL_GPL(inet_csk_addr2sockaddr);
1067 #ifdef CONFIG_COMPAT
1068 int inet_csk_compat_getsockopt(struct sock *sk, int level, int optname,
1069 char __user *optval, int __user *optlen)
1071 const struct inet_connection_sock *icsk = inet_csk(sk);
1073 if (icsk->icsk_af_ops->compat_getsockopt)
1074 return icsk->icsk_af_ops->compat_getsockopt(sk, level, optname,
1076 return icsk->icsk_af_ops->getsockopt(sk, level, optname,
1079 EXPORT_SYMBOL_GPL(inet_csk_compat_getsockopt);
1081 int inet_csk_compat_setsockopt(struct sock *sk, int level, int optname,
1082 char __user *optval, unsigned int optlen)
1084 const struct inet_connection_sock *icsk = inet_csk(sk);
1086 if (icsk->icsk_af_ops->compat_setsockopt)
1087 return icsk->icsk_af_ops->compat_setsockopt(sk, level, optname,
1089 return icsk->icsk_af_ops->setsockopt(sk, level, optname,
1092 EXPORT_SYMBOL_GPL(inet_csk_compat_setsockopt);
1095 static struct dst_entry *inet_csk_rebuild_route(struct sock *sk, struct flowi *fl)
1097 const struct inet_sock *inet = inet_sk(sk);
1098 const struct ip_options_rcu *inet_opt;
1099 __be32 daddr = inet->inet_daddr;
1104 inet_opt = rcu_dereference(inet->inet_opt);
1105 if (inet_opt && inet_opt->opt.srr)
1106 daddr = inet_opt->opt.faddr;
1108 rt = ip_route_output_ports(sock_net(sk), fl4, sk, daddr,
1109 inet->inet_saddr, inet->inet_dport,
1110 inet->inet_sport, sk->sk_protocol,
1111 RT_CONN_FLAGS(sk), sk->sk_bound_dev_if);
1115 sk_setup_caps(sk, &rt->dst);
1121 struct dst_entry *inet_csk_update_pmtu(struct sock *sk, u32 mtu)
1123 struct dst_entry *dst = __sk_dst_check(sk, 0);
1124 struct inet_sock *inet = inet_sk(sk);
1127 dst = inet_csk_rebuild_route(sk, &inet->cork.fl);
1131 dst->ops->update_pmtu(dst, sk, NULL, mtu, true);
1133 dst = __sk_dst_check(sk, 0);
1135 dst = inet_csk_rebuild_route(sk, &inet->cork.fl);
1139 EXPORT_SYMBOL_GPL(inet_csk_update_pmtu);