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_wildcard == true: IPV6_ADDR_ANY equals to any IPv6 addresses if IPv6
28 * only, and any IPv4 addresses if not IPv6 only
29 * match_wildcard == false: addresses must be exactly the same, i.e.
30 * IPV6_ADDR_ANY only equals to IPV6_ADDR_ANY,
31 * and 0.0.0.0 equals to 0.0.0.0 only
33 static bool ipv6_rcv_saddr_equal(const struct in6_addr *sk1_rcv_saddr6,
34 const struct in6_addr *sk2_rcv_saddr6,
35 __be32 sk1_rcv_saddr, __be32 sk2_rcv_saddr,
36 bool sk1_ipv6only, bool sk2_ipv6only,
39 int addr_type = ipv6_addr_type(sk1_rcv_saddr6);
40 int addr_type2 = sk2_rcv_saddr6 ? ipv6_addr_type(sk2_rcv_saddr6) : IPV6_ADDR_MAPPED;
42 /* if both are mapped, treat as IPv4 */
43 if (addr_type == IPV6_ADDR_MAPPED && addr_type2 == IPV6_ADDR_MAPPED) {
45 if (sk1_rcv_saddr == sk2_rcv_saddr)
47 if (!sk1_rcv_saddr || !sk2_rcv_saddr)
48 return match_wildcard;
53 if (addr_type == IPV6_ADDR_ANY && addr_type2 == IPV6_ADDR_ANY)
56 if (addr_type2 == IPV6_ADDR_ANY && match_wildcard &&
57 !(sk2_ipv6only && addr_type == IPV6_ADDR_MAPPED))
60 if (addr_type == IPV6_ADDR_ANY && match_wildcard &&
61 !(sk1_ipv6only && addr_type2 == IPV6_ADDR_MAPPED))
65 ipv6_addr_equal(sk1_rcv_saddr6, sk2_rcv_saddr6))
72 /* match_wildcard == true: 0.0.0.0 equals to any IPv4 addresses
73 * match_wildcard == false: addresses must be exactly the same, i.e.
74 * 0.0.0.0 only equals to 0.0.0.0
76 static bool ipv4_rcv_saddr_equal(__be32 sk1_rcv_saddr, __be32 sk2_rcv_saddr,
77 bool sk2_ipv6only, bool match_wildcard)
80 if (sk1_rcv_saddr == sk2_rcv_saddr)
82 if (!sk1_rcv_saddr || !sk2_rcv_saddr)
83 return match_wildcard;
88 bool inet_rcv_saddr_equal(const struct sock *sk, const struct sock *sk2,
91 #if IS_ENABLED(CONFIG_IPV6)
92 if (sk->sk_family == AF_INET6)
93 return ipv6_rcv_saddr_equal(&sk->sk_v6_rcv_saddr,
101 return ipv4_rcv_saddr_equal(sk->sk_rcv_saddr, sk2->sk_rcv_saddr,
102 ipv6_only_sock(sk2), match_wildcard);
104 EXPORT_SYMBOL(inet_rcv_saddr_equal);
106 bool inet_rcv_saddr_any(const struct sock *sk)
108 #if IS_ENABLED(CONFIG_IPV6)
109 if (sk->sk_family == AF_INET6)
110 return ipv6_addr_any(&sk->sk_v6_rcv_saddr);
112 return !sk->sk_rcv_saddr;
115 void inet_get_local_port_range(struct net *net, int *low, int *high)
120 seq = read_seqbegin(&net->ipv4.ip_local_ports.lock);
122 *low = net->ipv4.ip_local_ports.range[0];
123 *high = net->ipv4.ip_local_ports.range[1];
124 } while (read_seqretry(&net->ipv4.ip_local_ports.lock, seq));
126 EXPORT_SYMBOL(inet_get_local_port_range);
128 static int inet_csk_bind_conflict(const struct sock *sk,
129 const struct inet_bind_bucket *tb,
130 bool relax, bool reuseport_ok)
133 bool reuse = sk->sk_reuse;
134 bool reuseport = !!sk->sk_reuseport && reuseport_ok;
135 kuid_t uid = sock_i_uid((struct sock *)sk);
138 * Unlike other sk lookup places we do not check
139 * for sk_net here, since _all_ the socks listed
140 * in tb->owners list belong to the same net - the
141 * one this bucket belongs to.
144 sk_for_each_bound(sk2, &tb->owners) {
146 (!sk->sk_bound_dev_if ||
147 !sk2->sk_bound_dev_if ||
148 sk->sk_bound_dev_if == sk2->sk_bound_dev_if)) {
149 if ((!reuse || !sk2->sk_reuse ||
150 sk2->sk_state == TCP_LISTEN) &&
151 (!reuseport || !sk2->sk_reuseport ||
152 rcu_access_pointer(sk->sk_reuseport_cb) ||
153 (sk2->sk_state != TCP_TIME_WAIT &&
154 !uid_eq(uid, sock_i_uid(sk2))))) {
155 if (inet_rcv_saddr_equal(sk, sk2, true))
158 if (!relax && reuse && sk2->sk_reuse &&
159 sk2->sk_state != TCP_LISTEN) {
160 if (inet_rcv_saddr_equal(sk, sk2, true))
169 * Find an open port number for the socket. Returns with the
170 * inet_bind_hashbucket lock held.
172 static struct inet_bind_hashbucket *
173 inet_csk_find_open_port(struct sock *sk, struct inet_bind_bucket **tb_ret, int *port_ret)
175 struct inet_hashinfo *hinfo = sk->sk_prot->h.hashinfo;
177 struct inet_bind_hashbucket *head;
178 struct net *net = sock_net(sk);
179 int i, low, high, attempt_half;
180 struct inet_bind_bucket *tb;
181 u32 remaining, offset;
184 l3mdev = inet_sk_bound_l3mdev(sk);
185 attempt_half = (sk->sk_reuse == SK_CAN_REUSE) ? 1 : 0;
187 inet_get_local_port_range(net, &low, &high);
188 high++; /* [32768, 60999] -> [32768, 61000[ */
192 int half = low + (((high - low) >> 2) << 1);
194 if (attempt_half == 1)
199 remaining = high - low;
200 if (likely(remaining > 1))
203 offset = prandom_u32() % remaining;
204 /* __inet_hash_connect() favors ports having @low parity
205 * We do the opposite to not pollute connect() users.
211 for (i = 0; i < remaining; i += 2, port += 2) {
212 if (unlikely(port >= high))
214 if (inet_is_local_reserved_port(net, port))
216 head = &hinfo->bhash[inet_bhashfn(net, port,
218 spin_lock_bh(&head->lock);
219 inet_bind_bucket_for_each(tb, &head->chain)
220 if (net_eq(ib_net(tb), net) && tb->l3mdev == l3mdev &&
222 if (!inet_csk_bind_conflict(sk, tb, false, false))
229 spin_unlock_bh(&head->lock);
235 goto other_parity_scan;
237 if (attempt_half == 1) {
238 /* OK we now try the upper half of the range */
240 goto other_half_scan;
249 static inline int sk_reuseport_match(struct inet_bind_bucket *tb,
252 kuid_t uid = sock_i_uid(sk);
254 if (tb->fastreuseport <= 0)
256 if (!sk->sk_reuseport)
258 if (rcu_access_pointer(sk->sk_reuseport_cb))
260 if (!uid_eq(tb->fastuid, uid))
262 /* We only need to check the rcv_saddr if this tb was once marked
263 * without fastreuseport and then was reset, as we can only know that
264 * the fast_*rcv_saddr doesn't have any conflicts with the socks on the
267 if (tb->fastreuseport == FASTREUSEPORT_ANY)
269 #if IS_ENABLED(CONFIG_IPV6)
270 if (tb->fast_sk_family == AF_INET6)
271 return ipv6_rcv_saddr_equal(&tb->fast_v6_rcv_saddr,
276 ipv6_only_sock(sk), true);
278 return ipv4_rcv_saddr_equal(tb->fast_rcv_saddr, sk->sk_rcv_saddr,
279 ipv6_only_sock(sk), true);
282 /* Obtain a reference to a local port for the given sock,
283 * if snum is zero it means select any available local port.
284 * We try to allocate an odd port (and leave even ports for connect())
286 int inet_csk_get_port(struct sock *sk, unsigned short snum)
288 bool reuse = sk->sk_reuse && sk->sk_state != TCP_LISTEN;
289 struct inet_hashinfo *hinfo = sk->sk_prot->h.hashinfo;
290 int ret = 1, port = snum;
291 struct inet_bind_hashbucket *head;
292 struct net *net = sock_net(sk);
293 struct inet_bind_bucket *tb = NULL;
294 kuid_t uid = sock_i_uid(sk);
297 l3mdev = inet_sk_bound_l3mdev(sk);
300 head = inet_csk_find_open_port(sk, &tb, &port);
307 head = &hinfo->bhash[inet_bhashfn(net, port,
309 spin_lock_bh(&head->lock);
310 inet_bind_bucket_for_each(tb, &head->chain)
311 if (net_eq(ib_net(tb), net) && tb->l3mdev == l3mdev &&
315 tb = inet_bind_bucket_create(hinfo->bind_bucket_cachep,
316 net, head, port, l3mdev);
320 if (!hlist_empty(&tb->owners)) {
321 if (sk->sk_reuse == SK_FORCE_REUSE)
324 if ((tb->fastreuse > 0 && reuse) ||
325 sk_reuseport_match(tb, sk))
327 if (inet_csk_bind_conflict(sk, tb, true, true))
331 if (hlist_empty(&tb->owners)) {
332 tb->fastreuse = reuse;
333 if (sk->sk_reuseport) {
334 tb->fastreuseport = FASTREUSEPORT_ANY;
336 tb->fast_rcv_saddr = sk->sk_rcv_saddr;
337 tb->fast_ipv6_only = ipv6_only_sock(sk);
338 tb->fast_sk_family = sk->sk_family;
339 #if IS_ENABLED(CONFIG_IPV6)
340 tb->fast_v6_rcv_saddr = sk->sk_v6_rcv_saddr;
343 tb->fastreuseport = 0;
348 if (sk->sk_reuseport) {
349 /* We didn't match or we don't have fastreuseport set on
350 * the tb, but we have sk_reuseport set on this socket
351 * and we know that there are no bind conflicts with
352 * this socket in this tb, so reset our tb's reuseport
353 * settings so that any subsequent sockets that match
354 * our current socket will be put on the fast path.
356 * If we reset we need to set FASTREUSEPORT_STRICT so we
357 * do extra checking for all subsequent sk_reuseport
360 if (!sk_reuseport_match(tb, sk)) {
361 tb->fastreuseport = FASTREUSEPORT_STRICT;
363 tb->fast_rcv_saddr = sk->sk_rcv_saddr;
364 tb->fast_ipv6_only = ipv6_only_sock(sk);
365 tb->fast_sk_family = sk->sk_family;
366 #if IS_ENABLED(CONFIG_IPV6)
367 tb->fast_v6_rcv_saddr = sk->sk_v6_rcv_saddr;
371 tb->fastreuseport = 0;
374 if (!inet_csk(sk)->icsk_bind_hash)
375 inet_bind_hash(sk, tb, port);
376 WARN_ON(inet_csk(sk)->icsk_bind_hash != tb);
380 spin_unlock_bh(&head->lock);
383 EXPORT_SYMBOL_GPL(inet_csk_get_port);
386 * Wait for an incoming connection, avoid race conditions. This must be called
387 * with the socket locked.
389 static int inet_csk_wait_for_connect(struct sock *sk, long timeo)
391 struct inet_connection_sock *icsk = inet_csk(sk);
396 * True wake-one mechanism for incoming connections: only
397 * one process gets woken up, not the 'whole herd'.
398 * Since we do not 'race & poll' for established sockets
399 * anymore, the common case will execute the loop only once.
401 * Subtle issue: "add_wait_queue_exclusive()" will be added
402 * after any current non-exclusive waiters, and we know that
403 * it will always _stay_ after any new non-exclusive waiters
404 * because all non-exclusive waiters are added at the
405 * beginning of the wait-queue. As such, it's ok to "drop"
406 * our exclusiveness temporarily when we get woken up without
407 * having to remove and re-insert us on the wait queue.
410 prepare_to_wait_exclusive(sk_sleep(sk), &wait,
413 if (reqsk_queue_empty(&icsk->icsk_accept_queue))
414 timeo = schedule_timeout(timeo);
415 sched_annotate_sleep();
418 if (!reqsk_queue_empty(&icsk->icsk_accept_queue))
421 if (sk->sk_state != TCP_LISTEN)
423 err = sock_intr_errno(timeo);
424 if (signal_pending(current))
430 finish_wait(sk_sleep(sk), &wait);
435 * This will accept the next outstanding connection.
437 struct sock *inet_csk_accept(struct sock *sk, int flags, int *err, bool kern)
439 struct inet_connection_sock *icsk = inet_csk(sk);
440 struct request_sock_queue *queue = &icsk->icsk_accept_queue;
441 struct request_sock *req;
447 /* We need to make sure that this socket is listening,
448 * and that it has something pending.
451 if (sk->sk_state != TCP_LISTEN)
454 /* Find already established connection */
455 if (reqsk_queue_empty(queue)) {
456 long timeo = sock_rcvtimeo(sk, flags & O_NONBLOCK);
458 /* If this is a non blocking socket don't sleep */
463 error = inet_csk_wait_for_connect(sk, timeo);
467 req = reqsk_queue_remove(queue, sk);
470 if (sk->sk_protocol == IPPROTO_TCP &&
471 tcp_rsk(req)->tfo_listener) {
472 spin_lock_bh(&queue->fastopenq.lock);
473 if (tcp_rsk(req)->tfo_listener) {
474 /* We are still waiting for the final ACK from 3WHS
475 * so can't free req now. Instead, we set req->sk to
476 * NULL to signify that the child socket is taken
477 * so reqsk_fastopen_remove() will free the req
478 * when 3WHS finishes (or is aborted).
483 spin_unlock_bh(&queue->fastopenq.lock);
496 EXPORT_SYMBOL(inet_csk_accept);
499 * Using different timers for retransmit, delayed acks and probes
500 * We may wish use just one timer maintaining a list of expire jiffies
503 void inet_csk_init_xmit_timers(struct sock *sk,
504 void (*retransmit_handler)(struct timer_list *t),
505 void (*delack_handler)(struct timer_list *t),
506 void (*keepalive_handler)(struct timer_list *t))
508 struct inet_connection_sock *icsk = inet_csk(sk);
510 timer_setup(&icsk->icsk_retransmit_timer, retransmit_handler, 0);
511 timer_setup(&icsk->icsk_delack_timer, delack_handler, 0);
512 timer_setup(&sk->sk_timer, keepalive_handler, 0);
513 icsk->icsk_pending = icsk->icsk_ack.pending = 0;
515 EXPORT_SYMBOL(inet_csk_init_xmit_timers);
517 void inet_csk_clear_xmit_timers(struct sock *sk)
519 struct inet_connection_sock *icsk = inet_csk(sk);
521 icsk->icsk_pending = icsk->icsk_ack.pending = icsk->icsk_ack.blocked = 0;
523 sk_stop_timer(sk, &icsk->icsk_retransmit_timer);
524 sk_stop_timer(sk, &icsk->icsk_delack_timer);
525 sk_stop_timer(sk, &sk->sk_timer);
527 EXPORT_SYMBOL(inet_csk_clear_xmit_timers);
529 void inet_csk_delete_keepalive_timer(struct sock *sk)
531 sk_stop_timer(sk, &sk->sk_timer);
533 EXPORT_SYMBOL(inet_csk_delete_keepalive_timer);
535 void inet_csk_reset_keepalive_timer(struct sock *sk, unsigned long len)
537 sk_reset_timer(sk, &sk->sk_timer, jiffies + len);
539 EXPORT_SYMBOL(inet_csk_reset_keepalive_timer);
541 struct dst_entry *inet_csk_route_req(const struct sock *sk,
543 const struct request_sock *req)
545 const struct inet_request_sock *ireq = inet_rsk(req);
546 struct net *net = read_pnet(&ireq->ireq_net);
547 struct ip_options_rcu *opt;
551 opt = rcu_dereference(ireq->ireq_opt);
553 flowi4_init_output(fl4, ireq->ir_iif, ireq->ir_mark,
554 RT_CONN_FLAGS(sk), RT_SCOPE_UNIVERSE,
555 sk->sk_protocol, inet_sk_flowi_flags(sk),
556 (opt && opt->opt.srr) ? opt->opt.faddr : ireq->ir_rmt_addr,
557 ireq->ir_loc_addr, ireq->ir_rmt_port,
558 htons(ireq->ir_num), sk->sk_uid);
559 security_req_classify_flow(req, flowi4_to_flowi(fl4));
560 rt = ip_route_output_flow(net, fl4, sk);
563 if (opt && opt->opt.is_strictroute && rt->rt_uses_gateway)
572 __IP_INC_STATS(net, IPSTATS_MIB_OUTNOROUTES);
575 EXPORT_SYMBOL_GPL(inet_csk_route_req);
577 struct dst_entry *inet_csk_route_child_sock(const struct sock *sk,
579 const struct request_sock *req)
581 const struct inet_request_sock *ireq = inet_rsk(req);
582 struct net *net = read_pnet(&ireq->ireq_net);
583 struct inet_sock *newinet = inet_sk(newsk);
584 struct ip_options_rcu *opt;
588 opt = rcu_dereference(ireq->ireq_opt);
589 fl4 = &newinet->cork.fl.u.ip4;
591 flowi4_init_output(fl4, ireq->ir_iif, ireq->ir_mark,
592 RT_CONN_FLAGS(sk), RT_SCOPE_UNIVERSE,
593 sk->sk_protocol, inet_sk_flowi_flags(sk),
594 (opt && opt->opt.srr) ? opt->opt.faddr : ireq->ir_rmt_addr,
595 ireq->ir_loc_addr, ireq->ir_rmt_port,
596 htons(ireq->ir_num), sk->sk_uid);
597 security_req_classify_flow(req, flowi4_to_flowi(fl4));
598 rt = ip_route_output_flow(net, fl4, sk);
601 if (opt && opt->opt.is_strictroute && rt->rt_uses_gateway)
608 __IP_INC_STATS(net, IPSTATS_MIB_OUTNOROUTES);
611 EXPORT_SYMBOL_GPL(inet_csk_route_child_sock);
613 /* Decide when to expire the request and when to resend SYN-ACK */
614 static inline void syn_ack_recalc(struct request_sock *req, const int thresh,
615 const int max_retries,
616 const u8 rskq_defer_accept,
617 int *expire, int *resend)
619 if (!rskq_defer_accept) {
620 *expire = req->num_timeout >= thresh;
624 *expire = req->num_timeout >= thresh &&
625 (!inet_rsk(req)->acked || req->num_timeout >= max_retries);
627 * Do not resend while waiting for data after ACK,
628 * start to resend on end of deferring period to give
629 * last chance for data or ACK to create established socket.
631 *resend = !inet_rsk(req)->acked ||
632 req->num_timeout >= rskq_defer_accept - 1;
635 int inet_rtx_syn_ack(const struct sock *parent, struct request_sock *req)
637 int err = req->rsk_ops->rtx_syn_ack(parent, req);
643 EXPORT_SYMBOL(inet_rtx_syn_ack);
645 /* return true if req was found in the ehash table */
646 static bool reqsk_queue_unlink(struct request_sock *req)
648 struct inet_hashinfo *hashinfo = req_to_sk(req)->sk_prot->h.hashinfo;
651 if (sk_hashed(req_to_sk(req))) {
652 spinlock_t *lock = inet_ehash_lockp(hashinfo, req->rsk_hash);
655 found = __sk_nulls_del_node_init_rcu(req_to_sk(req));
658 if (timer_pending(&req->rsk_timer) && del_timer_sync(&req->rsk_timer))
663 void inet_csk_reqsk_queue_drop(struct sock *sk, struct request_sock *req)
665 if (reqsk_queue_unlink(req)) {
666 reqsk_queue_removed(&inet_csk(sk)->icsk_accept_queue, req);
670 EXPORT_SYMBOL(inet_csk_reqsk_queue_drop);
672 void inet_csk_reqsk_queue_drop_and_put(struct sock *sk, struct request_sock *req)
674 inet_csk_reqsk_queue_drop(sk, req);
677 EXPORT_SYMBOL(inet_csk_reqsk_queue_drop_and_put);
679 static void reqsk_timer_handler(struct timer_list *t)
681 struct request_sock *req = from_timer(req, t, rsk_timer);
682 struct sock *sk_listener = req->rsk_listener;
683 struct net *net = sock_net(sk_listener);
684 struct inet_connection_sock *icsk = inet_csk(sk_listener);
685 struct request_sock_queue *queue = &icsk->icsk_accept_queue;
686 int qlen, expire = 0, resend = 0;
687 int max_retries, thresh;
690 if (inet_sk_state_load(sk_listener) != TCP_LISTEN)
693 max_retries = icsk->icsk_syn_retries ? : net->ipv4.sysctl_tcp_synack_retries;
694 thresh = max_retries;
695 /* Normally all the openreqs are young and become mature
696 * (i.e. converted to established socket) for first timeout.
697 * If synack was not acknowledged for 1 second, it means
698 * one of the following things: synack was lost, ack was lost,
699 * rtt is high or nobody planned to ack (i.e. synflood).
700 * When server is a bit loaded, queue is populated with old
701 * open requests, reducing effective size of queue.
702 * When server is well loaded, queue size reduces to zero
703 * after several minutes of work. It is not synflood,
704 * it is normal operation. The solution is pruning
705 * too old entries overriding normal timeout, when
706 * situation becomes dangerous.
708 * Essentially, we reserve half of room for young
709 * embrions; and abort old ones without pity, if old
710 * ones are about to clog our table.
712 qlen = reqsk_queue_len(queue);
713 if ((qlen << 1) > max(8U, READ_ONCE(sk_listener->sk_max_ack_backlog))) {
714 int young = reqsk_queue_len_young(queue) << 1;
723 defer_accept = READ_ONCE(queue->rskq_defer_accept);
725 max_retries = defer_accept;
726 syn_ack_recalc(req, thresh, max_retries, defer_accept,
728 req->rsk_ops->syn_ack_timeout(req);
731 !inet_rtx_syn_ack(sk_listener, req) ||
732 inet_rsk(req)->acked)) {
735 if (req->num_timeout++ == 0)
736 atomic_dec(&queue->young);
737 timeo = min(TCP_TIMEOUT_INIT << req->num_timeout, TCP_RTO_MAX);
738 mod_timer(&req->rsk_timer, jiffies + timeo);
742 inet_csk_reqsk_queue_drop_and_put(sk_listener, req);
745 static void reqsk_queue_hash_req(struct request_sock *req,
746 unsigned long timeout)
748 timer_setup(&req->rsk_timer, reqsk_timer_handler, TIMER_PINNED);
749 mod_timer(&req->rsk_timer, jiffies + timeout);
751 inet_ehash_insert(req_to_sk(req), NULL);
752 /* before letting lookups find us, make sure all req fields
753 * are committed to memory and refcnt initialized.
756 refcount_set(&req->rsk_refcnt, 2 + 1);
759 void inet_csk_reqsk_queue_hash_add(struct sock *sk, struct request_sock *req,
760 unsigned long timeout)
762 reqsk_queue_hash_req(req, timeout);
763 inet_csk_reqsk_queue_added(sk);
765 EXPORT_SYMBOL_GPL(inet_csk_reqsk_queue_hash_add);
767 static void inet_clone_ulp(const struct request_sock *req, struct sock *newsk,
768 const gfp_t priority)
770 struct inet_connection_sock *icsk = inet_csk(newsk);
772 if (!icsk->icsk_ulp_ops)
775 if (icsk->icsk_ulp_ops->clone)
776 icsk->icsk_ulp_ops->clone(req, newsk, priority);
780 * inet_csk_clone_lock - clone an inet socket, and lock its clone
781 * @sk: the socket to clone
783 * @priority: for allocation (%GFP_KERNEL, %GFP_ATOMIC, etc)
785 * Caller must unlock socket even in error path (bh_unlock_sock(newsk))
787 struct sock *inet_csk_clone_lock(const struct sock *sk,
788 const struct request_sock *req,
789 const gfp_t priority)
791 struct sock *newsk = sk_clone_lock(sk, priority);
794 struct inet_connection_sock *newicsk = inet_csk(newsk);
796 inet_sk_set_state(newsk, TCP_SYN_RECV);
797 newicsk->icsk_bind_hash = NULL;
799 inet_sk(newsk)->inet_dport = inet_rsk(req)->ir_rmt_port;
800 inet_sk(newsk)->inet_num = inet_rsk(req)->ir_num;
801 inet_sk(newsk)->inet_sport = htons(inet_rsk(req)->ir_num);
803 /* listeners have SOCK_RCU_FREE, not the children */
804 sock_reset_flag(newsk, SOCK_RCU_FREE);
806 inet_sk(newsk)->mc_list = NULL;
808 newsk->sk_mark = inet_rsk(req)->ir_mark;
809 atomic64_set(&newsk->sk_cookie,
810 atomic64_read(&inet_rsk(req)->ir_cookie));
812 newicsk->icsk_retransmits = 0;
813 newicsk->icsk_backoff = 0;
814 newicsk->icsk_probes_out = 0;
816 /* Deinitialize accept_queue to trap illegal accesses. */
817 memset(&newicsk->icsk_accept_queue, 0, sizeof(newicsk->icsk_accept_queue));
819 inet_clone_ulp(req, newsk, priority);
821 security_inet_csk_clone(newsk, req);
825 EXPORT_SYMBOL_GPL(inet_csk_clone_lock);
828 * At this point, there should be no process reference to this
829 * socket, and thus no user references at all. Therefore we
830 * can assume the socket waitqueue is inactive and nobody will
831 * try to jump onto it.
833 void inet_csk_destroy_sock(struct sock *sk)
835 WARN_ON(sk->sk_state != TCP_CLOSE);
836 WARN_ON(!sock_flag(sk, SOCK_DEAD));
838 /* It cannot be in hash table! */
839 WARN_ON(!sk_unhashed(sk));
841 /* If it has not 0 inet_sk(sk)->inet_num, it must be bound */
842 WARN_ON(inet_sk(sk)->inet_num && !inet_csk(sk)->icsk_bind_hash);
844 sk->sk_prot->destroy(sk);
846 sk_stream_kill_queues(sk);
848 xfrm_sk_free_policy(sk);
850 sk_refcnt_debug_release(sk);
852 percpu_counter_dec(sk->sk_prot->orphan_count);
856 EXPORT_SYMBOL(inet_csk_destroy_sock);
858 /* This function allows to force a closure of a socket after the call to
859 * tcp/dccp_create_openreq_child().
861 void inet_csk_prepare_forced_close(struct sock *sk)
862 __releases(&sk->sk_lock.slock)
864 /* sk_clone_lock locked the socket and set refcnt to 2 */
868 /* The below has to be done to allow calling inet_csk_destroy_sock */
869 sock_set_flag(sk, SOCK_DEAD);
870 percpu_counter_inc(sk->sk_prot->orphan_count);
871 inet_sk(sk)->inet_num = 0;
873 EXPORT_SYMBOL(inet_csk_prepare_forced_close);
875 int inet_csk_listen_start(struct sock *sk, int backlog)
877 struct inet_connection_sock *icsk = inet_csk(sk);
878 struct inet_sock *inet = inet_sk(sk);
879 int err = -EADDRINUSE;
881 reqsk_queue_alloc(&icsk->icsk_accept_queue);
883 sk->sk_ack_backlog = 0;
884 inet_csk_delack_init(sk);
886 /* There is race window here: we announce ourselves listening,
887 * but this transition is still not validated by get_port().
888 * It is OK, because this socket enters to hash table only
889 * after validation is complete.
891 inet_sk_state_store(sk, TCP_LISTEN);
892 if (!sk->sk_prot->get_port(sk, inet->inet_num)) {
893 inet->inet_sport = htons(inet->inet_num);
896 err = sk->sk_prot->hash(sk);
902 inet_sk_set_state(sk, TCP_CLOSE);
905 EXPORT_SYMBOL_GPL(inet_csk_listen_start);
907 static void inet_child_forget(struct sock *sk, struct request_sock *req,
910 sk->sk_prot->disconnect(child, O_NONBLOCK);
914 percpu_counter_inc(sk->sk_prot->orphan_count);
916 if (sk->sk_protocol == IPPROTO_TCP && tcp_rsk(req)->tfo_listener) {
917 BUG_ON(rcu_access_pointer(tcp_sk(child)->fastopen_rsk) != req);
918 BUG_ON(sk != req->rsk_listener);
920 /* Paranoid, to prevent race condition if
921 * an inbound pkt destined for child is
922 * blocked by sock lock in tcp_v4_rcv().
923 * Also to satisfy an assertion in
924 * tcp_v4_destroy_sock().
926 RCU_INIT_POINTER(tcp_sk(child)->fastopen_rsk, NULL);
928 inet_csk_destroy_sock(child);
931 struct sock *inet_csk_reqsk_queue_add(struct sock *sk,
932 struct request_sock *req,
935 struct request_sock_queue *queue = &inet_csk(sk)->icsk_accept_queue;
937 spin_lock(&queue->rskq_lock);
938 if (unlikely(sk->sk_state != TCP_LISTEN)) {
939 inet_child_forget(sk, req, child);
944 if (queue->rskq_accept_head == NULL)
945 WRITE_ONCE(queue->rskq_accept_head, req);
947 queue->rskq_accept_tail->dl_next = req;
948 queue->rskq_accept_tail = req;
949 sk_acceptq_added(sk);
951 spin_unlock(&queue->rskq_lock);
954 EXPORT_SYMBOL(inet_csk_reqsk_queue_add);
956 struct sock *inet_csk_complete_hashdance(struct sock *sk, struct sock *child,
957 struct request_sock *req, bool own_req)
960 inet_csk_reqsk_queue_drop(sk, req);
961 reqsk_queue_removed(&inet_csk(sk)->icsk_accept_queue, req);
962 if (inet_csk_reqsk_queue_add(sk, req, child))
965 /* Too bad, another child took ownership of the request, undo. */
966 bh_unlock_sock(child);
970 EXPORT_SYMBOL(inet_csk_complete_hashdance);
973 * This routine closes sockets which have been at least partially
974 * opened, but not yet accepted.
976 void inet_csk_listen_stop(struct sock *sk)
978 struct inet_connection_sock *icsk = inet_csk(sk);
979 struct request_sock_queue *queue = &icsk->icsk_accept_queue;
980 struct request_sock *next, *req;
982 /* Following specs, it would be better either to send FIN
983 * (and enter FIN-WAIT-1, it is normal close)
984 * or to send active reset (abort).
985 * Certainly, it is pretty dangerous while synflood, but it is
986 * bad justification for our negligence 8)
987 * To be honest, we are not able to make either
988 * of the variants now. --ANK
990 while ((req = reqsk_queue_remove(queue, sk)) != NULL) {
991 struct sock *child = req->sk;
995 WARN_ON(sock_owned_by_user(child));
998 inet_child_forget(sk, req, child);
1000 bh_unlock_sock(child);
1006 if (queue->fastopenq.rskq_rst_head) {
1007 /* Free all the reqs queued in rskq_rst_head. */
1008 spin_lock_bh(&queue->fastopenq.lock);
1009 req = queue->fastopenq.rskq_rst_head;
1010 queue->fastopenq.rskq_rst_head = NULL;
1011 spin_unlock_bh(&queue->fastopenq.lock);
1012 while (req != NULL) {
1013 next = req->dl_next;
1018 WARN_ON_ONCE(sk->sk_ack_backlog);
1020 EXPORT_SYMBOL_GPL(inet_csk_listen_stop);
1022 void inet_csk_addr2sockaddr(struct sock *sk, struct sockaddr *uaddr)
1024 struct sockaddr_in *sin = (struct sockaddr_in *)uaddr;
1025 const struct inet_sock *inet = inet_sk(sk);
1027 sin->sin_family = AF_INET;
1028 sin->sin_addr.s_addr = inet->inet_daddr;
1029 sin->sin_port = inet->inet_dport;
1031 EXPORT_SYMBOL_GPL(inet_csk_addr2sockaddr);
1033 #ifdef CONFIG_COMPAT
1034 int inet_csk_compat_getsockopt(struct sock *sk, int level, int optname,
1035 char __user *optval, int __user *optlen)
1037 const struct inet_connection_sock *icsk = inet_csk(sk);
1039 if (icsk->icsk_af_ops->compat_getsockopt)
1040 return icsk->icsk_af_ops->compat_getsockopt(sk, level, optname,
1042 return icsk->icsk_af_ops->getsockopt(sk, level, optname,
1045 EXPORT_SYMBOL_GPL(inet_csk_compat_getsockopt);
1047 int inet_csk_compat_setsockopt(struct sock *sk, int level, int optname,
1048 char __user *optval, unsigned int optlen)
1050 const struct inet_connection_sock *icsk = inet_csk(sk);
1052 if (icsk->icsk_af_ops->compat_setsockopt)
1053 return icsk->icsk_af_ops->compat_setsockopt(sk, level, optname,
1055 return icsk->icsk_af_ops->setsockopt(sk, level, optname,
1058 EXPORT_SYMBOL_GPL(inet_csk_compat_setsockopt);
1061 static struct dst_entry *inet_csk_rebuild_route(struct sock *sk, struct flowi *fl)
1063 const struct inet_sock *inet = inet_sk(sk);
1064 const struct ip_options_rcu *inet_opt;
1065 __be32 daddr = inet->inet_daddr;
1070 inet_opt = rcu_dereference(inet->inet_opt);
1071 if (inet_opt && inet_opt->opt.srr)
1072 daddr = inet_opt->opt.faddr;
1074 rt = ip_route_output_ports(sock_net(sk), fl4, sk, daddr,
1075 inet->inet_saddr, inet->inet_dport,
1076 inet->inet_sport, sk->sk_protocol,
1077 RT_CONN_FLAGS(sk), sk->sk_bound_dev_if);
1081 sk_setup_caps(sk, &rt->dst);
1087 struct dst_entry *inet_csk_update_pmtu(struct sock *sk, u32 mtu)
1089 struct dst_entry *dst = __sk_dst_check(sk, 0);
1090 struct inet_sock *inet = inet_sk(sk);
1093 dst = inet_csk_rebuild_route(sk, &inet->cork.fl);
1097 dst->ops->update_pmtu(dst, sk, NULL, mtu, true);
1099 dst = __sk_dst_check(sk, 0);
1101 dst = inet_csk_rebuild_route(sk, &inet->cork.fl);
1105 EXPORT_SYMBOL_GPL(inet_csk_update_pmtu);