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.
6 * Implementation of the Transmission Control Protocol(TCP).
8 * Version: $Id: tcp_ipv4.c,v 1.240 2002/02/01 22:01:04 davem Exp $
10 * IPv4 specific functions
15 * linux/ipv4/tcp_input.c
16 * linux/ipv4/tcp_output.c
18 * See tcp.c for author information
20 * This program is free software; you can redistribute it and/or
21 * modify it under the terms of the GNU General Public License
22 * as published by the Free Software Foundation; either version
23 * 2 of the License, or (at your option) any later version.
28 * David S. Miller : New socket lookup architecture.
29 * This code is dedicated to John Dyson.
30 * David S. Miller : Change semantics of established hash,
31 * half is devoted to TIME_WAIT sockets
32 * and the rest go in the other half.
33 * Andi Kleen : Add support for syncookies and fixed
34 * some bugs: ip options weren't passed to
35 * the TCP layer, missed a check for an
37 * Andi Kleen : Implemented fast path mtu discovery.
38 * Fixed many serious bugs in the
39 * open_request handling and moved
40 * most of it into the af independent code.
41 * Added tail drop and some other bugfixes.
42 * Added new listen sematics.
43 * Mike McLagan : Routing by source
44 * Juan Jose Ciarlante: ip_dynaddr bits
45 * Andi Kleen: various fixes.
46 * Vitaly E. Lavrov : Transparent proxy revived after year
48 * Andi Kleen : Fix new listen.
49 * Andi Kleen : Fix accept error reporting.
50 * YOSHIFUJI Hideaki @USAGI and: Support IPV6_V6ONLY socket option, which
51 * Alexey Kuznetsov allow both IPv4 and IPv6 sockets to bind
52 * a single port at the same time.
55 #include <linux/config.h>
57 #include <linux/types.h>
58 #include <linux/fcntl.h>
59 #include <linux/module.h>
60 #include <linux/random.h>
61 #include <linux/cache.h>
62 #include <linux/jhash.h>
63 #include <linux/init.h>
64 #include <linux/times.h>
69 #include <net/inet_common.h>
72 #include <linux/inet.h>
73 #include <linux/ipv6.h>
74 #include <linux/stddef.h>
75 #include <linux/proc_fs.h>
76 #include <linux/seq_file.h>
78 extern int sysctl_ip_dynaddr;
79 int sysctl_tcp_tw_reuse;
80 int sysctl_tcp_low_latency;
82 /* Check TCP sequence numbers in ICMP packets. */
83 #define ICMP_MIN_LENGTH 8
85 /* Socket used for sending RSTs */
86 static struct socket *tcp_socket;
88 void tcp_v4_send_check(struct sock *sk, struct tcphdr *th, int len,
91 struct tcp_hashinfo __cacheline_aligned tcp_hashinfo = {
92 .__tcp_lhash_lock = RW_LOCK_UNLOCKED,
93 .__tcp_lhash_users = ATOMIC_INIT(0),
95 = __WAIT_QUEUE_HEAD_INITIALIZER(tcp_hashinfo.__tcp_lhash_wait),
96 .__tcp_portalloc_lock = SPIN_LOCK_UNLOCKED
100 * This array holds the first and last local port number.
101 * For high-usage systems, use sysctl to change this to
104 int sysctl_local_port_range[2] = { 1024, 4999 };
105 int tcp_port_rover = 1024 - 1;
107 static __inline__ int tcp_hashfn(__u32 laddr, __u16 lport,
108 __u32 faddr, __u16 fport)
110 int h = (laddr ^ lport) ^ (faddr ^ fport);
113 return h & (tcp_ehash_size - 1);
116 static __inline__ int tcp_sk_hashfn(struct sock *sk)
118 struct inet_sock *inet = inet_sk(sk);
119 __u32 laddr = inet->rcv_saddr;
120 __u16 lport = inet->num;
121 __u32 faddr = inet->daddr;
122 __u16 fport = inet->dport;
124 return tcp_hashfn(laddr, lport, faddr, fport);
127 /* Allocate and initialize a new TCP local port bind bucket.
128 * The bindhash mutex for snum's hash chain must be held here.
130 struct tcp_bind_bucket *tcp_bucket_create(struct tcp_bind_hashbucket *head,
133 struct tcp_bind_bucket *tb = kmem_cache_alloc(tcp_bucket_cachep,
138 INIT_HLIST_HEAD(&tb->owners);
139 hlist_add_head(&tb->node, &head->chain);
144 /* Caller must hold hashbucket lock for this tb with local BH disabled */
145 void tcp_bucket_destroy(struct tcp_bind_bucket *tb)
147 if (hlist_empty(&tb->owners)) {
148 __hlist_del(&tb->node);
149 kmem_cache_free(tcp_bucket_cachep, tb);
153 /* Caller must disable local BH processing. */
154 static __inline__ void __tcp_inherit_port(struct sock *sk, struct sock *child)
156 struct tcp_bind_hashbucket *head =
157 &tcp_bhash[tcp_bhashfn(inet_sk(child)->num)];
158 struct tcp_bind_bucket *tb;
160 spin_lock(&head->lock);
161 tb = tcp_sk(sk)->bind_hash;
162 sk_add_bind_node(child, &tb->owners);
163 tcp_sk(child)->bind_hash = tb;
164 spin_unlock(&head->lock);
167 inline void tcp_inherit_port(struct sock *sk, struct sock *child)
170 __tcp_inherit_port(sk, child);
174 void tcp_bind_hash(struct sock *sk, struct tcp_bind_bucket *tb,
177 inet_sk(sk)->num = snum;
178 sk_add_bind_node(sk, &tb->owners);
179 tcp_sk(sk)->bind_hash = tb;
182 static inline int tcp_bind_conflict(struct sock *sk, struct tcp_bind_bucket *tb)
184 const u32 sk_rcv_saddr = tcp_v4_rcv_saddr(sk);
186 struct hlist_node *node;
187 int reuse = sk->sk_reuse;
189 sk_for_each_bound(sk2, node, &tb->owners) {
191 !tcp_v6_ipv6only(sk2) &&
192 (!sk->sk_bound_dev_if ||
193 !sk2->sk_bound_dev_if ||
194 sk->sk_bound_dev_if == sk2->sk_bound_dev_if)) {
195 if (!reuse || !sk2->sk_reuse ||
196 sk2->sk_state == TCP_LISTEN) {
197 const u32 sk2_rcv_saddr = tcp_v4_rcv_saddr(sk2);
198 if (!sk2_rcv_saddr || !sk_rcv_saddr ||
199 sk2_rcv_saddr == sk_rcv_saddr)
207 /* Obtain a reference to a local port for the given sock,
208 * if snum is zero it means select any available local port.
210 static int tcp_v4_get_port(struct sock *sk, unsigned short snum)
212 struct tcp_bind_hashbucket *head;
213 struct hlist_node *node;
214 struct tcp_bind_bucket *tb;
219 int low = sysctl_local_port_range[0];
220 int high = sysctl_local_port_range[1];
221 int remaining = (high - low) + 1;
224 spin_lock(&tcp_portalloc_lock);
225 if (tcp_port_rover < low)
228 rover = tcp_port_rover;
233 head = &tcp_bhash[tcp_bhashfn(rover)];
234 spin_lock(&head->lock);
235 tb_for_each(tb, node, &head->chain)
236 if (tb->port == rover)
240 spin_unlock(&head->lock);
241 } while (--remaining > 0);
242 tcp_port_rover = rover;
243 spin_unlock(&tcp_portalloc_lock);
245 /* Exhausted local port range during search? */
250 /* OK, here is the one we will use. HEAD is
251 * non-NULL and we hold it's mutex.
255 head = &tcp_bhash[tcp_bhashfn(snum)];
256 spin_lock(&head->lock);
257 tb_for_each(tb, node, &head->chain)
258 if (tb->port == snum)
264 if (!hlist_empty(&tb->owners)) {
265 if (sk->sk_reuse > 1)
267 if (tb->fastreuse > 0 &&
268 sk->sk_reuse && sk->sk_state != TCP_LISTEN) {
272 if (tcp_bind_conflict(sk, tb))
278 if (!tb && (tb = tcp_bucket_create(head, snum)) == NULL)
280 if (hlist_empty(&tb->owners)) {
281 if (sk->sk_reuse && sk->sk_state != TCP_LISTEN)
285 } else if (tb->fastreuse &&
286 (!sk->sk_reuse || sk->sk_state == TCP_LISTEN))
289 if (!tcp_sk(sk)->bind_hash)
290 tcp_bind_hash(sk, tb, snum);
291 BUG_TRAP(tcp_sk(sk)->bind_hash == tb);
295 spin_unlock(&head->lock);
301 /* Get rid of any references to a local port held by the
304 static void __tcp_put_port(struct sock *sk)
306 struct inet_sock *inet = inet_sk(sk);
307 struct tcp_bind_hashbucket *head = &tcp_bhash[tcp_bhashfn(inet->num)];
308 struct tcp_bind_bucket *tb;
310 spin_lock(&head->lock);
311 tb = tcp_sk(sk)->bind_hash;
312 __sk_del_bind_node(sk);
313 tcp_sk(sk)->bind_hash = NULL;
315 tcp_bucket_destroy(tb);
316 spin_unlock(&head->lock);
319 void tcp_put_port(struct sock *sk)
326 /* This lock without WQ_FLAG_EXCLUSIVE is good on UP and it can be very bad on SMP.
327 * Look, when several writers sleep and reader wakes them up, all but one
328 * immediately hit write lock and grab all the cpus. Exclusive sleep solves
329 * this, _but_ remember, it adds useless work on UP machines (wake up each
330 * exclusive lock release). It should be ifdefed really.
333 void tcp_listen_wlock(void)
335 write_lock(&tcp_lhash_lock);
337 if (atomic_read(&tcp_lhash_users)) {
341 prepare_to_wait_exclusive(&tcp_lhash_wait,
342 &wait, TASK_UNINTERRUPTIBLE);
343 if (!atomic_read(&tcp_lhash_users))
345 write_unlock_bh(&tcp_lhash_lock);
347 write_lock_bh(&tcp_lhash_lock);
350 finish_wait(&tcp_lhash_wait, &wait);
354 static __inline__ void __tcp_v4_hash(struct sock *sk, const int listen_possible)
356 struct hlist_head *list;
359 BUG_TRAP(sk_unhashed(sk));
360 if (listen_possible && sk->sk_state == TCP_LISTEN) {
361 list = &tcp_listening_hash[tcp_sk_listen_hashfn(sk)];
362 lock = &tcp_lhash_lock;
365 list = &tcp_ehash[(sk->sk_hashent = tcp_sk_hashfn(sk))].chain;
366 lock = &tcp_ehash[sk->sk_hashent].lock;
369 __sk_add_node(sk, list);
370 sock_prot_inc_use(sk->sk_prot);
372 if (listen_possible && sk->sk_state == TCP_LISTEN)
373 wake_up(&tcp_lhash_wait);
376 static void tcp_v4_hash(struct sock *sk)
378 if (sk->sk_state != TCP_CLOSE) {
380 __tcp_v4_hash(sk, 1);
385 void tcp_unhash(struct sock *sk)
392 if (sk->sk_state == TCP_LISTEN) {
395 lock = &tcp_lhash_lock;
397 struct tcp_ehash_bucket *head = &tcp_ehash[sk->sk_hashent];
399 write_lock_bh(&head->lock);
402 if (__sk_del_node_init(sk))
403 sock_prot_dec_use(sk->sk_prot);
404 write_unlock_bh(lock);
407 if (sk->sk_state == TCP_LISTEN)
408 wake_up(&tcp_lhash_wait);
411 /* Don't inline this cruft. Here are some nice properties to
412 * exploit here. The BSD API does not allow a listening TCP
413 * to specify the remote port nor the remote address for the
414 * connection. So always assume those are both wildcarded
415 * during the search since they can never be otherwise.
417 static struct sock *__tcp_v4_lookup_listener(struct hlist_head *head, u32 daddr,
418 unsigned short hnum, int dif)
420 struct sock *result = NULL, *sk;
421 struct hlist_node *node;
425 sk_for_each(sk, node, head) {
426 struct inet_sock *inet = inet_sk(sk);
428 if (inet->num == hnum && !ipv6_only_sock(sk)) {
429 __u32 rcv_saddr = inet->rcv_saddr;
431 score = (sk->sk_family == PF_INET ? 1 : 0);
433 if (rcv_saddr != daddr)
437 if (sk->sk_bound_dev_if) {
438 if (sk->sk_bound_dev_if != dif)
444 if (score > hiscore) {
453 /* Optimize the common listener case. */
454 static inline struct sock *tcp_v4_lookup_listener(u32 daddr,
455 unsigned short hnum, int dif)
457 struct sock *sk = NULL;
458 struct hlist_head *head;
460 read_lock(&tcp_lhash_lock);
461 head = &tcp_listening_hash[tcp_lhashfn(hnum)];
462 if (!hlist_empty(head)) {
463 struct inet_sock *inet = inet_sk((sk = __sk_head(head)));
465 if (inet->num == hnum && !sk->sk_node.next &&
466 (!inet->rcv_saddr || inet->rcv_saddr == daddr) &&
467 (sk->sk_family == PF_INET || !ipv6_only_sock(sk)) &&
468 !sk->sk_bound_dev_if)
470 sk = __tcp_v4_lookup_listener(head, daddr, hnum, dif);
476 read_unlock(&tcp_lhash_lock);
480 /* Sockets in TCP_CLOSE state are _always_ taken out of the hash, so
481 * we need not check it for TCP lookups anymore, thanks Alexey. -DaveM
483 * Local BH must be disabled here.
486 static inline struct sock *__tcp_v4_lookup_established(u32 saddr, u16 sport,
490 struct tcp_ehash_bucket *head;
491 TCP_V4_ADDR_COOKIE(acookie, saddr, daddr)
492 __u32 ports = TCP_COMBINED_PORTS(sport, hnum);
494 struct hlist_node *node;
495 /* Optimize here for direct hit, only listening connections can
496 * have wildcards anyways.
498 int hash = tcp_hashfn(daddr, hnum, saddr, sport);
499 head = &tcp_ehash[hash];
500 read_lock(&head->lock);
501 sk_for_each(sk, node, &head->chain) {
502 if (TCP_IPV4_MATCH(sk, acookie, saddr, daddr, ports, dif))
503 goto hit; /* You sunk my battleship! */
506 /* Must check for a TIME_WAIT'er before going to listener hash. */
507 sk_for_each(sk, node, &(head + tcp_ehash_size)->chain) {
508 if (TCP_IPV4_TW_MATCH(sk, acookie, saddr, daddr, ports, dif))
513 read_unlock(&head->lock);
520 static inline struct sock *__tcp_v4_lookup(u32 saddr, u16 sport,
521 u32 daddr, u16 hnum, int dif)
523 struct sock *sk = __tcp_v4_lookup_established(saddr, sport,
526 return sk ? : tcp_v4_lookup_listener(daddr, hnum, dif);
529 inline struct sock *tcp_v4_lookup(u32 saddr, u16 sport, u32 daddr,
535 sk = __tcp_v4_lookup(saddr, sport, daddr, ntohs(dport), dif);
541 EXPORT_SYMBOL_GPL(tcp_v4_lookup);
543 static inline __u32 tcp_v4_init_sequence(struct sock *sk, struct sk_buff *skb)
545 return secure_tcp_sequence_number(skb->nh.iph->daddr,
551 /* called with local bh disabled */
552 static int __tcp_v4_check_established(struct sock *sk, __u16 lport,
553 struct tcp_tw_bucket **twp)
555 struct inet_sock *inet = inet_sk(sk);
556 u32 daddr = inet->rcv_saddr;
557 u32 saddr = inet->daddr;
558 int dif = sk->sk_bound_dev_if;
559 TCP_V4_ADDR_COOKIE(acookie, saddr, daddr)
560 __u32 ports = TCP_COMBINED_PORTS(inet->dport, lport);
561 int hash = tcp_hashfn(daddr, lport, saddr, inet->dport);
562 struct tcp_ehash_bucket *head = &tcp_ehash[hash];
564 struct hlist_node *node;
565 struct tcp_tw_bucket *tw;
567 write_lock(&head->lock);
569 /* Check TIME-WAIT sockets first. */
570 sk_for_each(sk2, node, &(head + tcp_ehash_size)->chain) {
571 tw = (struct tcp_tw_bucket *)sk2;
573 if (TCP_IPV4_TW_MATCH(sk2, acookie, saddr, daddr, ports, dif)) {
574 struct tcp_sock *tp = tcp_sk(sk);
576 /* With PAWS, it is safe from the viewpoint
577 of data integrity. Even without PAWS it
578 is safe provided sequence spaces do not
579 overlap i.e. at data rates <= 80Mbit/sec.
581 Actually, the idea is close to VJ's one,
582 only timestamp cache is held not per host,
583 but per port pair and TW bucket is used
586 If TW bucket has been already destroyed we
587 fall back to VJ's scheme and use initial
588 timestamp retrieved from peer table.
590 if (tw->tw_ts_recent_stamp &&
591 (!twp || (sysctl_tcp_tw_reuse &&
593 tw->tw_ts_recent_stamp > 1))) {
595 tw->tw_snd_nxt + 65535 + 2) == 0)
597 tp->rx_opt.ts_recent = tw->tw_ts_recent;
598 tp->rx_opt.ts_recent_stamp = tw->tw_ts_recent_stamp;
607 /* And established part... */
608 sk_for_each(sk2, node, &head->chain) {
609 if (TCP_IPV4_MATCH(sk2, acookie, saddr, daddr, ports, dif))
614 /* Must record num and sport now. Otherwise we will see
615 * in hash table socket with a funny identity. */
617 inet->sport = htons(lport);
618 sk->sk_hashent = hash;
619 BUG_TRAP(sk_unhashed(sk));
620 __sk_add_node(sk, &head->chain);
621 sock_prot_inc_use(sk->sk_prot);
622 write_unlock(&head->lock);
626 NET_INC_STATS_BH(LINUX_MIB_TIMEWAITRECYCLED);
628 /* Silly. Should hash-dance instead... */
629 tcp_tw_deschedule(tw);
630 NET_INC_STATS_BH(LINUX_MIB_TIMEWAITRECYCLED);
638 write_unlock(&head->lock);
639 return -EADDRNOTAVAIL;
642 static inline u32 connect_port_offset(const struct sock *sk)
644 const struct inet_sock *inet = inet_sk(sk);
646 return secure_tcp_port_ephemeral(inet->rcv_saddr, inet->daddr,
651 * Bind a port for a connect operation and hash it.
653 static inline int tcp_v4_hash_connect(struct sock *sk)
655 unsigned short snum = inet_sk(sk)->num;
656 struct tcp_bind_hashbucket *head;
657 struct tcp_bind_bucket *tb;
661 int low = sysctl_local_port_range[0];
662 int high = sysctl_local_port_range[1];
663 int range = high - low;
667 u32 offset = hint + connect_port_offset(sk);
668 struct hlist_node *node;
669 struct tcp_tw_bucket *tw = NULL;
672 for (i = 1; i <= range; i++) {
673 port = low + (i + offset) % range;
674 head = &tcp_bhash[tcp_bhashfn(port)];
675 spin_lock(&head->lock);
677 /* Does not bother with rcv_saddr checks,
678 * because the established check is already
681 tb_for_each(tb, node, &head->chain) {
682 if (tb->port == port) {
683 BUG_TRAP(!hlist_empty(&tb->owners));
684 if (tb->fastreuse >= 0)
686 if (!__tcp_v4_check_established(sk,
694 tb = tcp_bucket_create(head, port);
696 spin_unlock(&head->lock);
703 spin_unlock(&head->lock);
707 return -EADDRNOTAVAIL;
712 /* Head lock still held and bh's disabled */
713 tcp_bind_hash(sk, tb, port);
714 if (sk_unhashed(sk)) {
715 inet_sk(sk)->sport = htons(port);
716 __tcp_v4_hash(sk, 0);
718 spin_unlock(&head->lock);
721 tcp_tw_deschedule(tw);
729 head = &tcp_bhash[tcp_bhashfn(snum)];
730 tb = tcp_sk(sk)->bind_hash;
731 spin_lock_bh(&head->lock);
732 if (sk_head(&tb->owners) == sk && !sk->sk_bind_node.next) {
733 __tcp_v4_hash(sk, 0);
734 spin_unlock_bh(&head->lock);
737 spin_unlock(&head->lock);
738 /* No definite answer... Walk to established hash table */
739 ret = __tcp_v4_check_established(sk, snum, NULL);
746 /* This will initiate an outgoing connection. */
747 int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
749 struct inet_sock *inet = inet_sk(sk);
750 struct tcp_sock *tp = tcp_sk(sk);
751 struct sockaddr_in *usin = (struct sockaddr_in *)uaddr;
757 if (addr_len < sizeof(struct sockaddr_in))
760 if (usin->sin_family != AF_INET)
761 return -EAFNOSUPPORT;
763 nexthop = daddr = usin->sin_addr.s_addr;
764 if (inet->opt && inet->opt->srr) {
767 nexthop = inet->opt->faddr;
770 tmp = ip_route_connect(&rt, nexthop, inet->saddr,
771 RT_CONN_FLAGS(sk), sk->sk_bound_dev_if,
773 inet->sport, usin->sin_port, sk);
777 if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) {
782 if (!inet->opt || !inet->opt->srr)
786 inet->saddr = rt->rt_src;
787 inet->rcv_saddr = inet->saddr;
789 if (tp->rx_opt.ts_recent_stamp && inet->daddr != daddr) {
790 /* Reset inherited state */
791 tp->rx_opt.ts_recent = 0;
792 tp->rx_opt.ts_recent_stamp = 0;
796 if (sysctl_tcp_tw_recycle &&
797 !tp->rx_opt.ts_recent_stamp && rt->rt_dst == daddr) {
798 struct inet_peer *peer = rt_get_peer(rt);
800 /* VJ's idea. We save last timestamp seen from
801 * the destination in peer table, when entering state TIME-WAIT
802 * and initialize rx_opt.ts_recent from it, when trying new connection.
805 if (peer && peer->tcp_ts_stamp + TCP_PAWS_MSL >= xtime.tv_sec) {
806 tp->rx_opt.ts_recent_stamp = peer->tcp_ts_stamp;
807 tp->rx_opt.ts_recent = peer->tcp_ts;
811 inet->dport = usin->sin_port;
814 tp->ext_header_len = 0;
816 tp->ext_header_len = inet->opt->optlen;
818 tp->rx_opt.mss_clamp = 536;
820 /* Socket identity is still unknown (sport may be zero).
821 * However we set state to SYN-SENT and not releasing socket
822 * lock select source port, enter ourselves into the hash tables and
823 * complete initialization after this.
825 tcp_set_state(sk, TCP_SYN_SENT);
826 err = tcp_v4_hash_connect(sk);
830 err = ip_route_newports(&rt, inet->sport, inet->dport, sk);
834 /* OK, now commit destination to socket. */
835 __sk_dst_set(sk, &rt->u.dst);
836 tcp_v4_setup_caps(sk, &rt->u.dst);
839 tp->write_seq = secure_tcp_sequence_number(inet->saddr,
844 inet->id = tp->write_seq ^ jiffies;
846 err = tcp_connect(sk);
854 /* This unhashes the socket and releases the local port, if necessary. */
855 tcp_set_state(sk, TCP_CLOSE);
857 sk->sk_route_caps = 0;
862 static __inline__ int tcp_v4_iif(struct sk_buff *skb)
864 return ((struct rtable *)skb->dst)->rt_iif;
867 static __inline__ u32 tcp_v4_synq_hash(u32 raddr, u16 rport, u32 rnd)
869 return (jhash_2words(raddr, (u32) rport, rnd) & (TCP_SYNQ_HSIZE - 1));
872 static struct open_request *tcp_v4_search_req(struct tcp_sock *tp,
873 struct open_request ***prevp,
875 __u32 raddr, __u32 laddr)
877 struct tcp_listen_opt *lopt = tp->listen_opt;
878 struct open_request *req, **prev;
880 for (prev = &lopt->syn_table[tcp_v4_synq_hash(raddr, rport, lopt->hash_rnd)];
881 (req = *prev) != NULL;
882 prev = &req->dl_next) {
883 const struct inet_request_sock *ireq = inet_rsk(req);
885 if (ireq->rmt_port == rport &&
886 ireq->rmt_addr == raddr &&
887 ireq->loc_addr == laddr &&
888 TCP_INET_FAMILY(req->class->family)) {
898 static void tcp_v4_synq_add(struct sock *sk, struct open_request *req)
900 struct tcp_sock *tp = tcp_sk(sk);
901 struct tcp_listen_opt *lopt = tp->listen_opt;
902 u32 h = tcp_v4_synq_hash(inet_rsk(req)->rmt_addr, inet_rsk(req)->rmt_port, lopt->hash_rnd);
904 req->expires = jiffies + TCP_TIMEOUT_INIT;
907 req->dl_next = lopt->syn_table[h];
909 write_lock(&tp->syn_wait_lock);
910 lopt->syn_table[h] = req;
911 write_unlock(&tp->syn_wait_lock);
918 * This routine does path mtu discovery as defined in RFC1191.
920 static inline void do_pmtu_discovery(struct sock *sk, struct iphdr *iph,
923 struct dst_entry *dst;
924 struct inet_sock *inet = inet_sk(sk);
925 struct tcp_sock *tp = tcp_sk(sk);
927 /* We are not interested in TCP_LISTEN and open_requests (SYN-ACKs
928 * send out by Linux are always <576bytes so they should go through
931 if (sk->sk_state == TCP_LISTEN)
934 /* We don't check in the destentry if pmtu discovery is forbidden
935 * on this route. We just assume that no packet_to_big packets
936 * are send back when pmtu discovery is not active.
937 * There is a small race when the user changes this flag in the
938 * route, but I think that's acceptable.
940 if ((dst = __sk_dst_check(sk, 0)) == NULL)
943 dst->ops->update_pmtu(dst, mtu);
945 /* Something is about to be wrong... Remember soft error
946 * for the case, if this connection will not able to recover.
948 if (mtu < dst_mtu(dst) && ip_dont_fragment(sk, dst))
949 sk->sk_err_soft = EMSGSIZE;
953 if (inet->pmtudisc != IP_PMTUDISC_DONT &&
954 tp->pmtu_cookie > mtu) {
955 tcp_sync_mss(sk, mtu);
957 /* Resend the TCP packet because it's
958 * clear that the old packet has been
959 * dropped. This is the new "fast" path mtu
962 tcp_simple_retransmit(sk);
963 } /* else let the usual retransmit timer handle it */
967 * This routine is called by the ICMP module when it gets some
968 * sort of error condition. If err < 0 then the socket should
969 * be closed and the error returned to the user. If err > 0
970 * it's just the icmp type << 8 | icmp code. After adjustment
971 * header points to the first 8 bytes of the tcp header. We need
972 * to find the appropriate port.
974 * The locking strategy used here is very "optimistic". When
975 * someone else accesses the socket the ICMP is just dropped
976 * and for some paths there is no check at all.
977 * A more general error queue to queue errors for later handling
978 * is probably better.
982 void tcp_v4_err(struct sk_buff *skb, u32 info)
984 struct iphdr *iph = (struct iphdr *)skb->data;
985 struct tcphdr *th = (struct tcphdr *)(skb->data + (iph->ihl << 2));
987 struct inet_sock *inet;
988 int type = skb->h.icmph->type;
989 int code = skb->h.icmph->code;
994 if (skb->len < (iph->ihl << 2) + 8) {
995 ICMP_INC_STATS_BH(ICMP_MIB_INERRORS);
999 sk = tcp_v4_lookup(iph->daddr, th->dest, iph->saddr,
1000 th->source, tcp_v4_iif(skb));
1002 ICMP_INC_STATS_BH(ICMP_MIB_INERRORS);
1005 if (sk->sk_state == TCP_TIME_WAIT) {
1006 tcp_tw_put((struct tcp_tw_bucket *)sk);
1011 /* If too many ICMPs get dropped on busy
1012 * servers this needs to be solved differently.
1014 if (sock_owned_by_user(sk))
1015 NET_INC_STATS_BH(LINUX_MIB_LOCKDROPPEDICMPS);
1017 if (sk->sk_state == TCP_CLOSE)
1021 seq = ntohl(th->seq);
1022 if (sk->sk_state != TCP_LISTEN &&
1023 !between(seq, tp->snd_una, tp->snd_nxt)) {
1024 NET_INC_STATS(LINUX_MIB_OUTOFWINDOWICMPS);
1029 case ICMP_SOURCE_QUENCH:
1030 /* Just silently ignore these. */
1032 case ICMP_PARAMETERPROB:
1035 case ICMP_DEST_UNREACH:
1036 if (code > NR_ICMP_UNREACH)
1039 if (code == ICMP_FRAG_NEEDED) { /* PMTU discovery (RFC1191) */
1040 if (!sock_owned_by_user(sk))
1041 do_pmtu_discovery(sk, iph, info);
1045 err = icmp_err_convert[code].errno;
1047 case ICMP_TIME_EXCEEDED:
1054 switch (sk->sk_state) {
1055 struct open_request *req, **prev;
1057 if (sock_owned_by_user(sk))
1060 req = tcp_v4_search_req(tp, &prev, th->dest,
1061 iph->daddr, iph->saddr);
1065 /* ICMPs are not backlogged, hence we cannot get
1066 an established socket here.
1070 if (seq != tcp_rsk(req)->snt_isn) {
1071 NET_INC_STATS_BH(LINUX_MIB_OUTOFWINDOWICMPS);
1076 * Still in SYN_RECV, just remove it silently.
1077 * There is no good way to pass the error to the newly
1078 * created socket, and POSIX does not want network
1079 * errors returned from accept().
1081 tcp_synq_drop(sk, req, prev);
1085 case TCP_SYN_RECV: /* Cannot happen.
1086 It can f.e. if SYNs crossed.
1088 if (!sock_owned_by_user(sk)) {
1089 TCP_INC_STATS_BH(TCP_MIB_ATTEMPTFAILS);
1092 sk->sk_error_report(sk);
1096 sk->sk_err_soft = err;
1101 /* If we've already connected we will keep trying
1102 * until we time out, or the user gives up.
1104 * rfc1122 4.2.3.9 allows to consider as hard errors
1105 * only PROTO_UNREACH and PORT_UNREACH (well, FRAG_FAILED too,
1106 * but it is obsoleted by pmtu discovery).
1108 * Note, that in modern internet, where routing is unreliable
1109 * and in each dark corner broken firewalls sit, sending random
1110 * errors ordered by their masters even this two messages finally lose
1111 * their original sense (even Linux sends invalid PORT_UNREACHs)
1113 * Now we are in compliance with RFCs.
1118 if (!sock_owned_by_user(sk) && inet->recverr) {
1120 sk->sk_error_report(sk);
1121 } else { /* Only an error on timeout */
1122 sk->sk_err_soft = err;
1130 /* This routine computes an IPv4 TCP checksum. */
1131 void tcp_v4_send_check(struct sock *sk, struct tcphdr *th, int len,
1132 struct sk_buff *skb)
1134 struct inet_sock *inet = inet_sk(sk);
1136 if (skb->ip_summed == CHECKSUM_HW) {
1137 th->check = ~tcp_v4_check(th, len, inet->saddr, inet->daddr, 0);
1138 skb->csum = offsetof(struct tcphdr, check);
1140 th->check = tcp_v4_check(th, len, inet->saddr, inet->daddr,
1141 csum_partial((char *)th,
1148 * This routine will send an RST to the other tcp.
1150 * Someone asks: why I NEVER use socket parameters (TOS, TTL etc.)
1152 * Answer: if a packet caused RST, it is not for a socket
1153 * existing in our system, if it is matched to a socket,
1154 * it is just duplicate segment or bug in other side's TCP.
1155 * So that we build reply only basing on parameters
1156 * arrived with segment.
1157 * Exception: precedence violation. We do not implement it in any case.
1160 static void tcp_v4_send_reset(struct sk_buff *skb)
1162 struct tcphdr *th = skb->h.th;
1164 struct ip_reply_arg arg;
1166 /* Never send a reset in response to a reset. */
1170 if (((struct rtable *)skb->dst)->rt_type != RTN_LOCAL)
1173 /* Swap the send and the receive. */
1174 memset(&rth, 0, sizeof(struct tcphdr));
1175 rth.dest = th->source;
1176 rth.source = th->dest;
1177 rth.doff = sizeof(struct tcphdr) / 4;
1181 rth.seq = th->ack_seq;
1184 rth.ack_seq = htonl(ntohl(th->seq) + th->syn + th->fin +
1185 skb->len - (th->doff << 2));
1188 memset(&arg, 0, sizeof arg);
1189 arg.iov[0].iov_base = (unsigned char *)&rth;
1190 arg.iov[0].iov_len = sizeof rth;
1191 arg.csum = csum_tcpudp_nofold(skb->nh.iph->daddr,
1192 skb->nh.iph->saddr, /*XXX*/
1193 sizeof(struct tcphdr), IPPROTO_TCP, 0);
1194 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
1196 ip_send_reply(tcp_socket->sk, skb, &arg, sizeof rth);
1198 TCP_INC_STATS_BH(TCP_MIB_OUTSEGS);
1199 TCP_INC_STATS_BH(TCP_MIB_OUTRSTS);
1202 /* The code following below sending ACKs in SYN-RECV and TIME-WAIT states
1203 outside socket context is ugly, certainly. What can I do?
1206 static void tcp_v4_send_ack(struct sk_buff *skb, u32 seq, u32 ack,
1209 struct tcphdr *th = skb->h.th;
1214 struct ip_reply_arg arg;
1216 memset(&rep.th, 0, sizeof(struct tcphdr));
1217 memset(&arg, 0, sizeof arg);
1219 arg.iov[0].iov_base = (unsigned char *)&rep;
1220 arg.iov[0].iov_len = sizeof(rep.th);
1222 rep.tsopt[0] = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
1223 (TCPOPT_TIMESTAMP << 8) |
1225 rep.tsopt[1] = htonl(tcp_time_stamp);
1226 rep.tsopt[2] = htonl(ts);
1227 arg.iov[0].iov_len = sizeof(rep);
1230 /* Swap the send and the receive. */
1231 rep.th.dest = th->source;
1232 rep.th.source = th->dest;
1233 rep.th.doff = arg.iov[0].iov_len / 4;
1234 rep.th.seq = htonl(seq);
1235 rep.th.ack_seq = htonl(ack);
1237 rep.th.window = htons(win);
1239 arg.csum = csum_tcpudp_nofold(skb->nh.iph->daddr,
1240 skb->nh.iph->saddr, /*XXX*/
1241 arg.iov[0].iov_len, IPPROTO_TCP, 0);
1242 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
1244 ip_send_reply(tcp_socket->sk, skb, &arg, arg.iov[0].iov_len);
1246 TCP_INC_STATS_BH(TCP_MIB_OUTSEGS);
1249 static void tcp_v4_timewait_ack(struct sock *sk, struct sk_buff *skb)
1251 struct tcp_tw_bucket *tw = (struct tcp_tw_bucket *)sk;
1253 tcp_v4_send_ack(skb, tw->tw_snd_nxt, tw->tw_rcv_nxt,
1254 tw->tw_rcv_wnd >> tw->tw_rcv_wscale, tw->tw_ts_recent);
1259 static void tcp_v4_or_send_ack(struct sk_buff *skb, struct open_request *req)
1261 tcp_v4_send_ack(skb, tcp_rsk(req)->snt_isn + 1, tcp_rsk(req)->rcv_isn + 1, req->rcv_wnd,
1265 static struct dst_entry* tcp_v4_route_req(struct sock *sk,
1266 struct open_request *req)
1269 const struct inet_request_sock *ireq = inet_rsk(req);
1270 struct ip_options *opt = inet_rsk(req)->opt;
1271 struct flowi fl = { .oif = sk->sk_bound_dev_if,
1273 { .daddr = ((opt && opt->srr) ?
1276 .saddr = ireq->loc_addr,
1277 .tos = RT_CONN_FLAGS(sk) } },
1278 .proto = IPPROTO_TCP,
1280 { .sport = inet_sk(sk)->sport,
1281 .dport = ireq->rmt_port } } };
1283 if (ip_route_output_flow(&rt, &fl, sk, 0)) {
1284 IP_INC_STATS_BH(IPSTATS_MIB_OUTNOROUTES);
1287 if (opt && opt->is_strictroute && rt->rt_dst != rt->rt_gateway) {
1289 IP_INC_STATS_BH(IPSTATS_MIB_OUTNOROUTES);
1296 * Send a SYN-ACK after having received an ACK.
1297 * This still operates on a open_request only, not on a big
1300 static int tcp_v4_send_synack(struct sock *sk, struct open_request *req,
1301 struct dst_entry *dst)
1303 const struct inet_request_sock *ireq = inet_rsk(req);
1305 struct sk_buff * skb;
1307 /* First, grab a route. */
1308 if (!dst && (dst = tcp_v4_route_req(sk, req)) == NULL)
1311 skb = tcp_make_synack(sk, dst, req);
1314 struct tcphdr *th = skb->h.th;
1316 th->check = tcp_v4_check(th, skb->len,
1319 csum_partial((char *)th, skb->len,
1322 err = ip_build_and_send_pkt(skb, sk, ireq->loc_addr,
1325 if (err == NET_XMIT_CN)
1335 * IPv4 open_request destructor.
1337 static void tcp_v4_or_free(struct open_request *req)
1339 if (inet_rsk(req)->opt)
1340 kfree(inet_rsk(req)->opt);
1343 static inline void syn_flood_warning(struct sk_buff *skb)
1345 static unsigned long warntime;
1347 if (time_after(jiffies, (warntime + HZ * 60))) {
1350 "possible SYN flooding on port %d. Sending cookies.\n",
1351 ntohs(skb->h.th->dest));
1356 * Save and compile IPv4 options into the open_request if needed.
1358 static inline struct ip_options *tcp_v4_save_options(struct sock *sk,
1359 struct sk_buff *skb)
1361 struct ip_options *opt = &(IPCB(skb)->opt);
1362 struct ip_options *dopt = NULL;
1364 if (opt && opt->optlen) {
1365 int opt_size = optlength(opt);
1366 dopt = kmalloc(opt_size, GFP_ATOMIC);
1368 if (ip_options_echo(dopt, skb)) {
1378 * Maximum number of SYN_RECV sockets in queue per LISTEN socket.
1379 * One SYN_RECV socket costs about 80bytes on a 32bit machine.
1380 * It would be better to replace it with a global counter for all sockets
1381 * but then some measure against one socket starving all other sockets
1384 * It was 128 by default. Experiments with real servers show, that
1385 * it is absolutely not enough even at 100conn/sec. 256 cures most
1386 * of problems. This value is adjusted to 128 for very small machines
1387 * (<=32Mb of memory) and to 1024 on normal or better ones (>=256Mb).
1388 * Further increasing requires to change hash table size.
1390 int sysctl_max_syn_backlog = 256;
1392 struct or_calltable or_ipv4 = {
1394 .obj_size = sizeof(struct tcp_request_sock),
1395 .rtx_syn_ack = tcp_v4_send_synack,
1396 .send_ack = tcp_v4_or_send_ack,
1397 .destructor = tcp_v4_or_free,
1398 .send_reset = tcp_v4_send_reset,
1401 int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
1403 struct inet_request_sock *ireq;
1404 struct tcp_options_received tmp_opt;
1405 struct open_request *req;
1406 __u32 saddr = skb->nh.iph->saddr;
1407 __u32 daddr = skb->nh.iph->daddr;
1408 __u32 isn = TCP_SKB_CB(skb)->when;
1409 struct dst_entry *dst = NULL;
1410 #ifdef CONFIG_SYN_COOKIES
1411 int want_cookie = 0;
1413 #define want_cookie 0 /* Argh, why doesn't gcc optimize this :( */
1416 /* Never answer to SYNs send to broadcast or multicast */
1417 if (((struct rtable *)skb->dst)->rt_flags &
1418 (RTCF_BROADCAST | RTCF_MULTICAST))
1421 /* TW buckets are converted to open requests without
1422 * limitations, they conserve resources and peer is
1423 * evidently real one.
1425 if (tcp_synq_is_full(sk) && !isn) {
1426 #ifdef CONFIG_SYN_COOKIES
1427 if (sysctl_tcp_syncookies) {
1434 /* Accept backlog is full. If we have already queued enough
1435 * of warm entries in syn queue, drop request. It is better than
1436 * clogging syn queue with openreqs with exponentially increasing
1439 if (sk_acceptq_is_full(sk) && tcp_synq_young(sk) > 1)
1442 req = tcp_openreq_alloc(&or_ipv4);
1446 tcp_clear_options(&tmp_opt);
1447 tmp_opt.mss_clamp = 536;
1448 tmp_opt.user_mss = tcp_sk(sk)->rx_opt.user_mss;
1450 tcp_parse_options(skb, &tmp_opt, 0);
1453 tcp_clear_options(&tmp_opt);
1454 tmp_opt.saw_tstamp = 0;
1457 if (tmp_opt.saw_tstamp && !tmp_opt.rcv_tsval) {
1458 /* Some OSes (unknown ones, but I see them on web server, which
1459 * contains information interesting only for windows'
1460 * users) do not send their stamp in SYN. It is easy case.
1461 * We simply do not advertise TS support.
1463 tmp_opt.saw_tstamp = 0;
1464 tmp_opt.tstamp_ok = 0;
1466 tmp_opt.tstamp_ok = tmp_opt.saw_tstamp;
1468 tcp_openreq_init(req, &tmp_opt, skb);
1470 ireq = inet_rsk(req);
1471 ireq->loc_addr = daddr;
1472 ireq->rmt_addr = saddr;
1473 ireq->opt = tcp_v4_save_options(sk, skb);
1475 TCP_ECN_create_request(req, skb->h.th);
1478 #ifdef CONFIG_SYN_COOKIES
1479 syn_flood_warning(skb);
1481 isn = cookie_v4_init_sequence(sk, skb, &req->mss);
1483 struct inet_peer *peer = NULL;
1485 /* VJ's idea. We save last timestamp seen
1486 * from the destination in peer table, when entering
1487 * state TIME-WAIT, and check against it before
1488 * accepting new connection request.
1490 * If "isn" is not zero, this request hit alive
1491 * timewait bucket, so that all the necessary checks
1492 * are made in the function processing timewait state.
1494 if (tmp_opt.saw_tstamp &&
1495 sysctl_tcp_tw_recycle &&
1496 (dst = tcp_v4_route_req(sk, req)) != NULL &&
1497 (peer = rt_get_peer((struct rtable *)dst)) != NULL &&
1498 peer->v4daddr == saddr) {
1499 if (xtime.tv_sec < peer->tcp_ts_stamp + TCP_PAWS_MSL &&
1500 (s32)(peer->tcp_ts - req->ts_recent) >
1502 NET_INC_STATS_BH(LINUX_MIB_PAWSPASSIVEREJECTED);
1507 /* Kill the following clause, if you dislike this way. */
1508 else if (!sysctl_tcp_syncookies &&
1509 (sysctl_max_syn_backlog - tcp_synq_len(sk) <
1510 (sysctl_max_syn_backlog >> 2)) &&
1511 (!peer || !peer->tcp_ts_stamp) &&
1512 (!dst || !dst_metric(dst, RTAX_RTT))) {
1513 /* Without syncookies last quarter of
1514 * backlog is filled with destinations,
1515 * proven to be alive.
1516 * It means that we continue to communicate
1517 * to destinations, already remembered
1518 * to the moment of synflood.
1520 NETDEBUG(if (net_ratelimit()) \
1521 printk(KERN_DEBUG "TCP: drop open "
1522 "request from %u.%u."
1525 ntohs(skb->h.th->source)));
1530 isn = tcp_v4_init_sequence(sk, skb);
1532 tcp_rsk(req)->snt_isn = isn;
1534 if (tcp_v4_send_synack(sk, req, dst))
1538 tcp_openreq_free(req);
1540 tcp_v4_synq_add(sk, req);
1545 tcp_openreq_free(req);
1547 TCP_INC_STATS_BH(TCP_MIB_ATTEMPTFAILS);
1553 * The three way handshake has completed - we got a valid synack -
1554 * now create the new socket.
1556 struct sock *tcp_v4_syn_recv_sock(struct sock *sk, struct sk_buff *skb,
1557 struct open_request *req,
1558 struct dst_entry *dst)
1560 struct inet_request_sock *ireq;
1561 struct inet_sock *newinet;
1562 struct tcp_sock *newtp;
1565 if (sk_acceptq_is_full(sk))
1568 if (!dst && (dst = tcp_v4_route_req(sk, req)) == NULL)
1571 newsk = tcp_create_openreq_child(sk, req, skb);
1575 newsk->sk_dst_cache = dst;
1576 tcp_v4_setup_caps(newsk, dst);
1578 newtp = tcp_sk(newsk);
1579 newinet = inet_sk(newsk);
1580 ireq = inet_rsk(req);
1581 newinet->daddr = ireq->rmt_addr;
1582 newinet->rcv_saddr = ireq->loc_addr;
1583 newinet->saddr = ireq->loc_addr;
1584 newinet->opt = ireq->opt;
1586 newinet->mc_index = tcp_v4_iif(skb);
1587 newinet->mc_ttl = skb->nh.iph->ttl;
1588 newtp->ext_header_len = 0;
1590 newtp->ext_header_len = newinet->opt->optlen;
1591 newinet->id = newtp->write_seq ^ jiffies;
1593 tcp_sync_mss(newsk, dst_mtu(dst));
1594 newtp->advmss = dst_metric(dst, RTAX_ADVMSS);
1595 tcp_initialize_rcv_mss(newsk);
1597 __tcp_v4_hash(newsk, 0);
1598 __tcp_inherit_port(sk, newsk);
1603 NET_INC_STATS_BH(LINUX_MIB_LISTENOVERFLOWS);
1605 NET_INC_STATS_BH(LINUX_MIB_LISTENDROPS);
1610 static struct sock *tcp_v4_hnd_req(struct sock *sk, struct sk_buff *skb)
1612 struct tcphdr *th = skb->h.th;
1613 struct iphdr *iph = skb->nh.iph;
1614 struct tcp_sock *tp = tcp_sk(sk);
1616 struct open_request **prev;
1617 /* Find possible connection requests. */
1618 struct open_request *req = tcp_v4_search_req(tp, &prev, th->source,
1619 iph->saddr, iph->daddr);
1621 return tcp_check_req(sk, skb, req, prev);
1623 nsk = __tcp_v4_lookup_established(skb->nh.iph->saddr,
1630 if (nsk->sk_state != TCP_TIME_WAIT) {
1634 tcp_tw_put((struct tcp_tw_bucket *)nsk);
1638 #ifdef CONFIG_SYN_COOKIES
1639 if (!th->rst && !th->syn && th->ack)
1640 sk = cookie_v4_check(sk, skb, &(IPCB(skb)->opt));
1645 static int tcp_v4_checksum_init(struct sk_buff *skb)
1647 if (skb->ip_summed == CHECKSUM_HW) {
1648 skb->ip_summed = CHECKSUM_UNNECESSARY;
1649 if (!tcp_v4_check(skb->h.th, skb->len, skb->nh.iph->saddr,
1650 skb->nh.iph->daddr, skb->csum))
1653 NETDEBUG(if (net_ratelimit())
1654 printk(KERN_DEBUG "hw tcp v4 csum failed\n"));
1655 skb->ip_summed = CHECKSUM_NONE;
1657 if (skb->len <= 76) {
1658 if (tcp_v4_check(skb->h.th, skb->len, skb->nh.iph->saddr,
1660 skb_checksum(skb, 0, skb->len, 0)))
1662 skb->ip_summed = CHECKSUM_UNNECESSARY;
1664 skb->csum = ~tcp_v4_check(skb->h.th, skb->len,
1666 skb->nh.iph->daddr, 0);
1672 /* The socket must have it's spinlock held when we get
1675 * We have a potential double-lock case here, so even when
1676 * doing backlog processing we use the BH locking scheme.
1677 * This is because we cannot sleep with the original spinlock
1680 int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
1682 if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
1683 TCP_CHECK_TIMER(sk);
1684 if (tcp_rcv_established(sk, skb, skb->h.th, skb->len))
1686 TCP_CHECK_TIMER(sk);
1690 if (skb->len < (skb->h.th->doff << 2) || tcp_checksum_complete(skb))
1693 if (sk->sk_state == TCP_LISTEN) {
1694 struct sock *nsk = tcp_v4_hnd_req(sk, skb);
1699 if (tcp_child_process(sk, nsk, skb))
1705 TCP_CHECK_TIMER(sk);
1706 if (tcp_rcv_state_process(sk, skb, skb->h.th, skb->len))
1708 TCP_CHECK_TIMER(sk);
1712 tcp_v4_send_reset(skb);
1715 /* Be careful here. If this function gets more complicated and
1716 * gcc suffers from register pressure on the x86, sk (in %ebx)
1717 * might be destroyed here. This current version compiles correctly,
1718 * but you have been warned.
1723 TCP_INC_STATS_BH(TCP_MIB_INERRS);
1731 int tcp_v4_rcv(struct sk_buff *skb)
1737 if (skb->pkt_type != PACKET_HOST)
1740 /* Count it even if it's bad */
1741 TCP_INC_STATS_BH(TCP_MIB_INSEGS);
1743 if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
1748 if (th->doff < sizeof(struct tcphdr) / 4)
1750 if (!pskb_may_pull(skb, th->doff * 4))
1753 /* An explanation is required here, I think.
1754 * Packet length and doff are validated by header prediction,
1755 * provided case of th->doff==0 is elimineted.
1756 * So, we defer the checks. */
1757 if ((skb->ip_summed != CHECKSUM_UNNECESSARY &&
1758 tcp_v4_checksum_init(skb) < 0))
1762 TCP_SKB_CB(skb)->seq = ntohl(th->seq);
1763 TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
1764 skb->len - th->doff * 4);
1765 TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
1766 TCP_SKB_CB(skb)->when = 0;
1767 TCP_SKB_CB(skb)->flags = skb->nh.iph->tos;
1768 TCP_SKB_CB(skb)->sacked = 0;
1770 sk = __tcp_v4_lookup(skb->nh.iph->saddr, th->source,
1771 skb->nh.iph->daddr, ntohs(th->dest),
1778 if (sk->sk_state == TCP_TIME_WAIT)
1781 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
1782 goto discard_and_relse;
1784 if (sk_filter(sk, skb, 0))
1785 goto discard_and_relse;
1791 if (!sock_owned_by_user(sk)) {
1792 if (!tcp_prequeue(sk, skb))
1793 ret = tcp_v4_do_rcv(sk, skb);
1795 sk_add_backlog(sk, skb);
1803 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
1806 if (skb->len < (th->doff << 2) || tcp_checksum_complete(skb)) {
1808 TCP_INC_STATS_BH(TCP_MIB_INERRS);
1810 tcp_v4_send_reset(skb);
1814 /* Discard frame. */
1823 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
1824 tcp_tw_put((struct tcp_tw_bucket *) sk);
1828 if (skb->len < (th->doff << 2) || tcp_checksum_complete(skb)) {
1829 TCP_INC_STATS_BH(TCP_MIB_INERRS);
1830 tcp_tw_put((struct tcp_tw_bucket *) sk);
1833 switch (tcp_timewait_state_process((struct tcp_tw_bucket *)sk,
1834 skb, th, skb->len)) {
1836 struct sock *sk2 = tcp_v4_lookup_listener(skb->nh.iph->daddr,
1840 tcp_tw_deschedule((struct tcp_tw_bucket *)sk);
1841 tcp_tw_put((struct tcp_tw_bucket *)sk);
1845 /* Fall through to ACK */
1848 tcp_v4_timewait_ack(sk, skb);
1852 case TCP_TW_SUCCESS:;
1857 /* With per-bucket locks this operation is not-atomic, so that
1858 * this version is not worse.
1860 static void __tcp_v4_rehash(struct sock *sk)
1862 sk->sk_prot->unhash(sk);
1863 sk->sk_prot->hash(sk);
1866 static int tcp_v4_reselect_saddr(struct sock *sk)
1868 struct inet_sock *inet = inet_sk(sk);
1871 __u32 old_saddr = inet->saddr;
1873 __u32 daddr = inet->daddr;
1875 if (inet->opt && inet->opt->srr)
1876 daddr = inet->opt->faddr;
1878 /* Query new route. */
1879 err = ip_route_connect(&rt, daddr, 0,
1881 sk->sk_bound_dev_if,
1883 inet->sport, inet->dport, sk);
1887 __sk_dst_set(sk, &rt->u.dst);
1888 tcp_v4_setup_caps(sk, &rt->u.dst);
1890 new_saddr = rt->rt_src;
1892 if (new_saddr == old_saddr)
1895 if (sysctl_ip_dynaddr > 1) {
1896 printk(KERN_INFO "tcp_v4_rebuild_header(): shifting inet->"
1897 "saddr from %d.%d.%d.%d to %d.%d.%d.%d\n",
1899 NIPQUAD(new_saddr));
1902 inet->saddr = new_saddr;
1903 inet->rcv_saddr = new_saddr;
1905 /* XXX The only one ugly spot where we need to
1906 * XXX really change the sockets identity after
1907 * XXX it has entered the hashes. -DaveM
1909 * Besides that, it does not check for connection
1910 * uniqueness. Wait for troubles.
1912 __tcp_v4_rehash(sk);
1916 int tcp_v4_rebuild_header(struct sock *sk)
1918 struct inet_sock *inet = inet_sk(sk);
1919 struct rtable *rt = (struct rtable *)__sk_dst_check(sk, 0);
1923 /* Route is OK, nothing to do. */
1928 daddr = inet->daddr;
1929 if (inet->opt && inet->opt->srr)
1930 daddr = inet->opt->faddr;
1933 struct flowi fl = { .oif = sk->sk_bound_dev_if,
1936 .saddr = inet->saddr,
1937 .tos = RT_CONN_FLAGS(sk) } },
1938 .proto = IPPROTO_TCP,
1940 { .sport = inet->sport,
1941 .dport = inet->dport } } };
1943 err = ip_route_output_flow(&rt, &fl, sk, 0);
1946 __sk_dst_set(sk, &rt->u.dst);
1947 tcp_v4_setup_caps(sk, &rt->u.dst);
1951 /* Routing failed... */
1952 sk->sk_route_caps = 0;
1954 if (!sysctl_ip_dynaddr ||
1955 sk->sk_state != TCP_SYN_SENT ||
1956 (sk->sk_userlocks & SOCK_BINDADDR_LOCK) ||
1957 (err = tcp_v4_reselect_saddr(sk)) != 0)
1958 sk->sk_err_soft = -err;
1963 static void v4_addr2sockaddr(struct sock *sk, struct sockaddr * uaddr)
1965 struct sockaddr_in *sin = (struct sockaddr_in *) uaddr;
1966 struct inet_sock *inet = inet_sk(sk);
1968 sin->sin_family = AF_INET;
1969 sin->sin_addr.s_addr = inet->daddr;
1970 sin->sin_port = inet->dport;
1973 /* VJ's idea. Save last timestamp seen from this destination
1974 * and hold it at least for normal timewait interval to use for duplicate
1975 * segment detection in subsequent connections, before they enter synchronized
1979 int tcp_v4_remember_stamp(struct sock *sk)
1981 struct inet_sock *inet = inet_sk(sk);
1982 struct tcp_sock *tp = tcp_sk(sk);
1983 struct rtable *rt = (struct rtable *)__sk_dst_get(sk);
1984 struct inet_peer *peer = NULL;
1987 if (!rt || rt->rt_dst != inet->daddr) {
1988 peer = inet_getpeer(inet->daddr, 1);
1992 rt_bind_peer(rt, 1);
1997 if ((s32)(peer->tcp_ts - tp->rx_opt.ts_recent) <= 0 ||
1998 (peer->tcp_ts_stamp + TCP_PAWS_MSL < xtime.tv_sec &&
1999 peer->tcp_ts_stamp <= tp->rx_opt.ts_recent_stamp)) {
2000 peer->tcp_ts_stamp = tp->rx_opt.ts_recent_stamp;
2001 peer->tcp_ts = tp->rx_opt.ts_recent;
2011 int tcp_v4_tw_remember_stamp(struct tcp_tw_bucket *tw)
2013 struct inet_peer *peer = NULL;
2015 peer = inet_getpeer(tw->tw_daddr, 1);
2018 if ((s32)(peer->tcp_ts - tw->tw_ts_recent) <= 0 ||
2019 (peer->tcp_ts_stamp + TCP_PAWS_MSL < xtime.tv_sec &&
2020 peer->tcp_ts_stamp <= tw->tw_ts_recent_stamp)) {
2021 peer->tcp_ts_stamp = tw->tw_ts_recent_stamp;
2022 peer->tcp_ts = tw->tw_ts_recent;
2031 struct tcp_func ipv4_specific = {
2032 .queue_xmit = ip_queue_xmit,
2033 .send_check = tcp_v4_send_check,
2034 .rebuild_header = tcp_v4_rebuild_header,
2035 .conn_request = tcp_v4_conn_request,
2036 .syn_recv_sock = tcp_v4_syn_recv_sock,
2037 .remember_stamp = tcp_v4_remember_stamp,
2038 .net_header_len = sizeof(struct iphdr),
2039 .setsockopt = ip_setsockopt,
2040 .getsockopt = ip_getsockopt,
2041 .addr2sockaddr = v4_addr2sockaddr,
2042 .sockaddr_len = sizeof(struct sockaddr_in),
2045 /* NOTE: A lot of things set to zero explicitly by call to
2046 * sk_alloc() so need not be done here.
2048 static int tcp_v4_init_sock(struct sock *sk)
2050 struct tcp_sock *tp = tcp_sk(sk);
2052 skb_queue_head_init(&tp->out_of_order_queue);
2053 tcp_init_xmit_timers(sk);
2054 tcp_prequeue_init(tp);
2056 tp->rto = TCP_TIMEOUT_INIT;
2057 tp->mdev = TCP_TIMEOUT_INIT;
2059 /* So many TCP implementations out there (incorrectly) count the
2060 * initial SYN frame in their delayed-ACK and congestion control
2061 * algorithms that we must have the following bandaid to talk
2062 * efficiently to them. -DaveM
2066 /* See draft-stevens-tcpca-spec-01 for discussion of the
2067 * initialization of these values.
2069 tp->snd_ssthresh = 0x7fffffff; /* Infinity */
2070 tp->snd_cwnd_clamp = ~0;
2071 tp->mss_cache_std = tp->mss_cache = 536;
2073 tp->reordering = sysctl_tcp_reordering;
2075 sk->sk_state = TCP_CLOSE;
2077 sk->sk_write_space = sk_stream_write_space;
2078 sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
2080 tp->af_specific = &ipv4_specific;
2082 sk->sk_sndbuf = sysctl_tcp_wmem[1];
2083 sk->sk_rcvbuf = sysctl_tcp_rmem[1];
2085 atomic_inc(&tcp_sockets_allocated);
2090 int tcp_v4_destroy_sock(struct sock *sk)
2092 struct tcp_sock *tp = tcp_sk(sk);
2094 tcp_clear_xmit_timers(sk);
2096 /* Cleanup up the write buffer. */
2097 sk_stream_writequeue_purge(sk);
2099 /* Cleans up our, hopefully empty, out_of_order_queue. */
2100 __skb_queue_purge(&tp->out_of_order_queue);
2102 /* Clean prequeue, it must be empty really */
2103 __skb_queue_purge(&tp->ucopy.prequeue);
2105 /* Clean up a referenced TCP bind bucket. */
2110 * If sendmsg cached page exists, toss it.
2112 if (sk->sk_sndmsg_page) {
2113 __free_page(sk->sk_sndmsg_page);
2114 sk->sk_sndmsg_page = NULL;
2117 atomic_dec(&tcp_sockets_allocated);
2122 EXPORT_SYMBOL(tcp_v4_destroy_sock);
2124 #ifdef CONFIG_PROC_FS
2125 /* Proc filesystem TCP sock list dumping. */
2127 static inline struct tcp_tw_bucket *tw_head(struct hlist_head *head)
2129 return hlist_empty(head) ? NULL :
2130 list_entry(head->first, struct tcp_tw_bucket, tw_node);
2133 static inline struct tcp_tw_bucket *tw_next(struct tcp_tw_bucket *tw)
2135 return tw->tw_node.next ?
2136 hlist_entry(tw->tw_node.next, typeof(*tw), tw_node) : NULL;
2139 static void *listening_get_next(struct seq_file *seq, void *cur)
2141 struct tcp_sock *tp;
2142 struct hlist_node *node;
2143 struct sock *sk = cur;
2144 struct tcp_iter_state* st = seq->private;
2148 sk = sk_head(&tcp_listening_hash[0]);
2154 if (st->state == TCP_SEQ_STATE_OPENREQ) {
2155 struct open_request *req = cur;
2157 tp = tcp_sk(st->syn_wait_sk);
2161 if (req->class->family == st->family) {
2167 if (++st->sbucket >= TCP_SYNQ_HSIZE)
2170 req = tp->listen_opt->syn_table[st->sbucket];
2172 sk = sk_next(st->syn_wait_sk);
2173 st->state = TCP_SEQ_STATE_LISTENING;
2174 read_unlock_bh(&tp->syn_wait_lock);
2177 read_lock_bh(&tp->syn_wait_lock);
2178 if (tp->listen_opt && tp->listen_opt->qlen)
2180 read_unlock_bh(&tp->syn_wait_lock);
2184 sk_for_each_from(sk, node) {
2185 if (sk->sk_family == st->family) {
2190 read_lock_bh(&tp->syn_wait_lock);
2191 if (tp->listen_opt && tp->listen_opt->qlen) {
2193 st->uid = sock_i_uid(sk);
2194 st->syn_wait_sk = sk;
2195 st->state = TCP_SEQ_STATE_OPENREQ;
2199 read_unlock_bh(&tp->syn_wait_lock);
2201 if (++st->bucket < TCP_LHTABLE_SIZE) {
2202 sk = sk_head(&tcp_listening_hash[st->bucket]);
2210 static void *listening_get_idx(struct seq_file *seq, loff_t *pos)
2212 void *rc = listening_get_next(seq, NULL);
2214 while (rc && *pos) {
2215 rc = listening_get_next(seq, rc);
2221 static void *established_get_first(struct seq_file *seq)
2223 struct tcp_iter_state* st = seq->private;
2226 for (st->bucket = 0; st->bucket < tcp_ehash_size; ++st->bucket) {
2228 struct hlist_node *node;
2229 struct tcp_tw_bucket *tw;
2231 /* We can reschedule _before_ having picked the target: */
2232 cond_resched_softirq();
2234 read_lock(&tcp_ehash[st->bucket].lock);
2235 sk_for_each(sk, node, &tcp_ehash[st->bucket].chain) {
2236 if (sk->sk_family != st->family) {
2242 st->state = TCP_SEQ_STATE_TIME_WAIT;
2243 tw_for_each(tw, node,
2244 &tcp_ehash[st->bucket + tcp_ehash_size].chain) {
2245 if (tw->tw_family != st->family) {
2251 read_unlock(&tcp_ehash[st->bucket].lock);
2252 st->state = TCP_SEQ_STATE_ESTABLISHED;
2258 static void *established_get_next(struct seq_file *seq, void *cur)
2260 struct sock *sk = cur;
2261 struct tcp_tw_bucket *tw;
2262 struct hlist_node *node;
2263 struct tcp_iter_state* st = seq->private;
2267 if (st->state == TCP_SEQ_STATE_TIME_WAIT) {
2271 while (tw && tw->tw_family != st->family) {
2278 read_unlock(&tcp_ehash[st->bucket].lock);
2279 st->state = TCP_SEQ_STATE_ESTABLISHED;
2281 /* We can reschedule between buckets: */
2282 cond_resched_softirq();
2284 if (++st->bucket < tcp_ehash_size) {
2285 read_lock(&tcp_ehash[st->bucket].lock);
2286 sk = sk_head(&tcp_ehash[st->bucket].chain);
2294 sk_for_each_from(sk, node) {
2295 if (sk->sk_family == st->family)
2299 st->state = TCP_SEQ_STATE_TIME_WAIT;
2300 tw = tw_head(&tcp_ehash[st->bucket + tcp_ehash_size].chain);
2308 static void *established_get_idx(struct seq_file *seq, loff_t pos)
2310 void *rc = established_get_first(seq);
2313 rc = established_get_next(seq, rc);
2319 static void *tcp_get_idx(struct seq_file *seq, loff_t pos)
2322 struct tcp_iter_state* st = seq->private;
2325 st->state = TCP_SEQ_STATE_LISTENING;
2326 rc = listening_get_idx(seq, &pos);
2329 tcp_listen_unlock();
2331 st->state = TCP_SEQ_STATE_ESTABLISHED;
2332 rc = established_get_idx(seq, pos);
2338 static void *tcp_seq_start(struct seq_file *seq, loff_t *pos)
2340 struct tcp_iter_state* st = seq->private;
2341 st->state = TCP_SEQ_STATE_LISTENING;
2343 return *pos ? tcp_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
2346 static void *tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2349 struct tcp_iter_state* st;
2351 if (v == SEQ_START_TOKEN) {
2352 rc = tcp_get_idx(seq, 0);
2357 switch (st->state) {
2358 case TCP_SEQ_STATE_OPENREQ:
2359 case TCP_SEQ_STATE_LISTENING:
2360 rc = listening_get_next(seq, v);
2362 tcp_listen_unlock();
2364 st->state = TCP_SEQ_STATE_ESTABLISHED;
2365 rc = established_get_first(seq);
2368 case TCP_SEQ_STATE_ESTABLISHED:
2369 case TCP_SEQ_STATE_TIME_WAIT:
2370 rc = established_get_next(seq, v);
2378 static void tcp_seq_stop(struct seq_file *seq, void *v)
2380 struct tcp_iter_state* st = seq->private;
2382 switch (st->state) {
2383 case TCP_SEQ_STATE_OPENREQ:
2385 struct tcp_sock *tp = tcp_sk(st->syn_wait_sk);
2386 read_unlock_bh(&tp->syn_wait_lock);
2388 case TCP_SEQ_STATE_LISTENING:
2389 if (v != SEQ_START_TOKEN)
2390 tcp_listen_unlock();
2392 case TCP_SEQ_STATE_TIME_WAIT:
2393 case TCP_SEQ_STATE_ESTABLISHED:
2395 read_unlock(&tcp_ehash[st->bucket].lock);
2401 static int tcp_seq_open(struct inode *inode, struct file *file)
2403 struct tcp_seq_afinfo *afinfo = PDE(inode)->data;
2404 struct seq_file *seq;
2405 struct tcp_iter_state *s;
2408 if (unlikely(afinfo == NULL))
2411 s = kmalloc(sizeof(*s), GFP_KERNEL);
2414 memset(s, 0, sizeof(*s));
2415 s->family = afinfo->family;
2416 s->seq_ops.start = tcp_seq_start;
2417 s->seq_ops.next = tcp_seq_next;
2418 s->seq_ops.show = afinfo->seq_show;
2419 s->seq_ops.stop = tcp_seq_stop;
2421 rc = seq_open(file, &s->seq_ops);
2424 seq = file->private_data;
2433 int tcp_proc_register(struct tcp_seq_afinfo *afinfo)
2436 struct proc_dir_entry *p;
2440 afinfo->seq_fops->owner = afinfo->owner;
2441 afinfo->seq_fops->open = tcp_seq_open;
2442 afinfo->seq_fops->read = seq_read;
2443 afinfo->seq_fops->llseek = seq_lseek;
2444 afinfo->seq_fops->release = seq_release_private;
2446 p = proc_net_fops_create(afinfo->name, S_IRUGO, afinfo->seq_fops);
2454 void tcp_proc_unregister(struct tcp_seq_afinfo *afinfo)
2458 proc_net_remove(afinfo->name);
2459 memset(afinfo->seq_fops, 0, sizeof(*afinfo->seq_fops));
2462 static void get_openreq4(struct sock *sk, struct open_request *req,
2463 char *tmpbuf, int i, int uid)
2465 const struct inet_request_sock *ireq = inet_rsk(req);
2466 int ttd = req->expires - jiffies;
2468 sprintf(tmpbuf, "%4d: %08X:%04X %08X:%04X"
2469 " %02X %08X:%08X %02X:%08lX %08X %5d %8d %u %d %p",
2472 ntohs(inet_sk(sk)->sport),
2474 ntohs(ireq->rmt_port),
2476 0, 0, /* could print option size, but that is af dependent. */
2477 1, /* timers active (only the expire timer) */
2478 jiffies_to_clock_t(ttd),
2481 0, /* non standard timer */
2482 0, /* open_requests have no inode */
2483 atomic_read(&sk->sk_refcnt),
2487 static void get_tcp4_sock(struct sock *sp, char *tmpbuf, int i)
2490 unsigned long timer_expires;
2491 struct tcp_sock *tp = tcp_sk(sp);
2492 struct inet_sock *inet = inet_sk(sp);
2493 unsigned int dest = inet->daddr;
2494 unsigned int src = inet->rcv_saddr;
2495 __u16 destp = ntohs(inet->dport);
2496 __u16 srcp = ntohs(inet->sport);
2498 if (tp->pending == TCP_TIME_RETRANS) {
2500 timer_expires = tp->timeout;
2501 } else if (tp->pending == TCP_TIME_PROBE0) {
2503 timer_expires = tp->timeout;
2504 } else if (timer_pending(&sp->sk_timer)) {
2506 timer_expires = sp->sk_timer.expires;
2509 timer_expires = jiffies;
2512 sprintf(tmpbuf, "%4d: %08X:%04X %08X:%04X %02X %08X:%08X %02X:%08lX "
2513 "%08X %5d %8d %lu %d %p %u %u %u %u %d",
2514 i, src, srcp, dest, destp, sp->sk_state,
2515 tp->write_seq - tp->snd_una, tp->rcv_nxt - tp->copied_seq,
2517 jiffies_to_clock_t(timer_expires - jiffies),
2522 atomic_read(&sp->sk_refcnt), sp,
2523 tp->rto, tp->ack.ato, (tp->ack.quick << 1) | tp->ack.pingpong,
2525 tp->snd_ssthresh >= 0xFFFF ? -1 : tp->snd_ssthresh);
2528 static void get_timewait4_sock(struct tcp_tw_bucket *tw, char *tmpbuf, int i)
2530 unsigned int dest, src;
2532 int ttd = tw->tw_ttd - jiffies;
2537 dest = tw->tw_daddr;
2538 src = tw->tw_rcv_saddr;
2539 destp = ntohs(tw->tw_dport);
2540 srcp = ntohs(tw->tw_sport);
2542 sprintf(tmpbuf, "%4d: %08X:%04X %08X:%04X"
2543 " %02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %p",
2544 i, src, srcp, dest, destp, tw->tw_substate, 0, 0,
2545 3, jiffies_to_clock_t(ttd), 0, 0, 0, 0,
2546 atomic_read(&tw->tw_refcnt), tw);
2551 static int tcp4_seq_show(struct seq_file *seq, void *v)
2553 struct tcp_iter_state* st;
2554 char tmpbuf[TMPSZ + 1];
2556 if (v == SEQ_START_TOKEN) {
2557 seq_printf(seq, "%-*s\n", TMPSZ - 1,
2558 " sl local_address rem_address st tx_queue "
2559 "rx_queue tr tm->when retrnsmt uid timeout "
2565 switch (st->state) {
2566 case TCP_SEQ_STATE_LISTENING:
2567 case TCP_SEQ_STATE_ESTABLISHED:
2568 get_tcp4_sock(v, tmpbuf, st->num);
2570 case TCP_SEQ_STATE_OPENREQ:
2571 get_openreq4(st->syn_wait_sk, v, tmpbuf, st->num, st->uid);
2573 case TCP_SEQ_STATE_TIME_WAIT:
2574 get_timewait4_sock(v, tmpbuf, st->num);
2577 seq_printf(seq, "%-*s\n", TMPSZ - 1, tmpbuf);
2582 static struct file_operations tcp4_seq_fops;
2583 static struct tcp_seq_afinfo tcp4_seq_afinfo = {
2584 .owner = THIS_MODULE,
2587 .seq_show = tcp4_seq_show,
2588 .seq_fops = &tcp4_seq_fops,
2591 int __init tcp4_proc_init(void)
2593 return tcp_proc_register(&tcp4_seq_afinfo);
2596 void tcp4_proc_exit(void)
2598 tcp_proc_unregister(&tcp4_seq_afinfo);
2600 #endif /* CONFIG_PROC_FS */
2602 struct proto tcp_prot = {
2604 .owner = THIS_MODULE,
2606 .connect = tcp_v4_connect,
2607 .disconnect = tcp_disconnect,
2608 .accept = tcp_accept,
2610 .init = tcp_v4_init_sock,
2611 .destroy = tcp_v4_destroy_sock,
2612 .shutdown = tcp_shutdown,
2613 .setsockopt = tcp_setsockopt,
2614 .getsockopt = tcp_getsockopt,
2615 .sendmsg = tcp_sendmsg,
2616 .recvmsg = tcp_recvmsg,
2617 .backlog_rcv = tcp_v4_do_rcv,
2618 .hash = tcp_v4_hash,
2619 .unhash = tcp_unhash,
2620 .get_port = tcp_v4_get_port,
2621 .enter_memory_pressure = tcp_enter_memory_pressure,
2622 .sockets_allocated = &tcp_sockets_allocated,
2623 .memory_allocated = &tcp_memory_allocated,
2624 .memory_pressure = &tcp_memory_pressure,
2625 .sysctl_mem = sysctl_tcp_mem,
2626 .sysctl_wmem = sysctl_tcp_wmem,
2627 .sysctl_rmem = sysctl_tcp_rmem,
2628 .max_header = MAX_TCP_HEADER,
2629 .obj_size = sizeof(struct tcp_sock),
2630 .rsk_prot = &or_ipv4,
2635 void __init tcp_v4_init(struct net_proto_family *ops)
2637 int err = sock_create_kern(PF_INET, SOCK_RAW, IPPROTO_TCP, &tcp_socket);
2639 panic("Failed to create the TCP control socket.\n");
2640 tcp_socket->sk->sk_allocation = GFP_ATOMIC;
2641 inet_sk(tcp_socket->sk)->uc_ttl = -1;
2643 /* Unhash it so that IP input processing does not even
2644 * see it, we do not wish this socket to see incoming
2647 tcp_socket->sk->sk_prot->unhash(tcp_socket->sk);
2650 EXPORT_SYMBOL(ipv4_specific);
2651 EXPORT_SYMBOL(tcp_bind_hash);
2652 EXPORT_SYMBOL(tcp_bucket_create);
2653 EXPORT_SYMBOL(tcp_hashinfo);
2654 EXPORT_SYMBOL(tcp_inherit_port);
2655 EXPORT_SYMBOL(tcp_listen_wlock);
2656 EXPORT_SYMBOL(tcp_port_rover);
2657 EXPORT_SYMBOL(tcp_prot);
2658 EXPORT_SYMBOL(tcp_put_port);
2659 EXPORT_SYMBOL(tcp_unhash);
2660 EXPORT_SYMBOL(tcp_v4_conn_request);
2661 EXPORT_SYMBOL(tcp_v4_connect);
2662 EXPORT_SYMBOL(tcp_v4_do_rcv);
2663 EXPORT_SYMBOL(tcp_v4_rebuild_header);
2664 EXPORT_SYMBOL(tcp_v4_remember_stamp);
2665 EXPORT_SYMBOL(tcp_v4_send_check);
2666 EXPORT_SYMBOL(tcp_v4_syn_recv_sock);
2668 #ifdef CONFIG_PROC_FS
2669 EXPORT_SYMBOL(tcp_proc_register);
2670 EXPORT_SYMBOL(tcp_proc_unregister);
2672 EXPORT_SYMBOL(sysctl_local_port_range);
2673 EXPORT_SYMBOL(sysctl_max_syn_backlog);
2674 EXPORT_SYMBOL(sysctl_tcp_low_latency);
2675 EXPORT_SYMBOL(sysctl_tcp_tw_reuse);