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).
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>
77 #include <linux/vserver/debug.h>
79 extern int sysctl_ip_dynaddr;
80 int sysctl_tcp_tw_reuse;
81 int sysctl_tcp_low_latency;
83 /* Check TCP sequence numbers in ICMP packets. */
84 #define ICMP_MIN_LENGTH 8
86 /* Socket used for sending RSTs */
87 static struct socket *tcp_socket;
89 void tcp_v4_send_check(struct sock *sk, struct tcphdr *th, int len,
92 struct tcp_hashinfo __cacheline_aligned tcp_hashinfo = {
93 .__tcp_lhash_lock = RW_LOCK_UNLOCKED,
94 .__tcp_lhash_users = ATOMIC_INIT(0),
96 = __WAIT_QUEUE_HEAD_INITIALIZER(tcp_hashinfo.__tcp_lhash_wait),
97 .__tcp_portalloc_lock = SPIN_LOCK_UNLOCKED
101 * This array holds the first and last local port number.
102 * For high-usage systems, use sysctl to change this to
105 int sysctl_local_port_range[2] = { 1024, 4999 };
106 int tcp_port_rover = 1024 - 1;
108 static __inline__ int tcp_hashfn(__u32 laddr, __u16 lport,
109 __u32 faddr, __u16 fport)
111 int h = (laddr ^ lport) ^ (faddr ^ fport);
114 return h & (tcp_ehash_size - 1);
117 static __inline__ int tcp_sk_hashfn(struct sock *sk)
119 struct inet_opt *inet = inet_sk(sk);
120 __u32 laddr = inet->rcv_saddr;
121 __u16 lport = inet->num;
122 __u32 faddr = inet->daddr;
123 __u16 fport = inet->dport;
125 return tcp_hashfn(laddr, lport, faddr, fport);
128 /* Allocate and initialize a new TCP local port bind bucket.
129 * The bindhash mutex for snum's hash chain must be held here.
131 struct tcp_bind_bucket *tcp_bucket_create(struct tcp_bind_hashbucket *head,
134 struct tcp_bind_bucket *tb = kmem_cache_alloc(tcp_bucket_cachep,
139 INIT_HLIST_HEAD(&tb->owners);
140 hlist_add_head(&tb->node, &head->chain);
145 /* Caller must hold hashbucket lock for this tb with local BH disabled */
146 void tcp_bucket_destroy(struct tcp_bind_bucket *tb)
148 if (hlist_empty(&tb->owners)) {
149 __hlist_del(&tb->node);
150 kmem_cache_free(tcp_bucket_cachep, tb);
154 /* Caller must disable local BH processing. */
155 static __inline__ void __tcp_inherit_port(struct sock *sk, struct sock *child)
157 struct tcp_bind_hashbucket *head =
158 &tcp_bhash[tcp_bhashfn(inet_sk(child)->num)];
159 struct tcp_bind_bucket *tb;
161 spin_lock(&head->lock);
162 tb = tcp_sk(sk)->bind_hash;
163 sk_add_bind_node(child, &tb->owners);
164 tcp_sk(child)->bind_hash = tb;
165 spin_unlock(&head->lock);
168 inline void tcp_inherit_port(struct sock *sk, struct sock *child)
171 __tcp_inherit_port(sk, child);
175 void tcp_bind_hash(struct sock *sk, struct tcp_bind_bucket *tb,
178 inet_sk(sk)->num = snum;
179 sk_add_bind_node(sk, &tb->owners);
180 tcp_sk(sk)->bind_hash = tb;
183 static inline int tcp_bind_conflict(struct sock *sk, struct tcp_bind_bucket *tb)
185 const u32 sk_rcv_saddr = tcp_v4_rcv_saddr(sk);
187 struct hlist_node *node;
188 int reuse = sk->sk_reuse;
190 sk_for_each_bound(sk2, node, &tb->owners) {
192 !tcp_v6_ipv6only(sk2) &&
193 (!sk->sk_bound_dev_if ||
194 !sk2->sk_bound_dev_if ||
195 sk->sk_bound_dev_if == sk2->sk_bound_dev_if)) {
196 if (!reuse || !sk2->sk_reuse ||
197 sk2->sk_state == TCP_LISTEN) {
198 const u32 sk2_rcv_saddr = tcp_v4_rcv_saddr(sk2);
199 if (!sk2_rcv_saddr || !sk_rcv_saddr ||
200 sk2_rcv_saddr == sk_rcv_saddr)
208 /* Obtain a reference to a local port for the given sock,
209 * if snum is zero it means select any available local port.
211 static int tcp_v4_get_port(struct sock *sk, unsigned short snum)
213 struct tcp_bind_hashbucket *head;
214 struct hlist_node *node;
215 struct tcp_bind_bucket *tb;
220 int low = sysctl_local_port_range[0];
221 int high = sysctl_local_port_range[1];
222 int remaining = (high - low) + 1;
225 spin_lock(&tcp_portalloc_lock);
226 rover = tcp_port_rover;
229 if (rover < low || rover > high)
231 head = &tcp_bhash[tcp_bhashfn(rover)];
232 spin_lock(&head->lock);
233 tb_for_each(tb, node, &head->chain)
234 if (tb->port == rover)
238 spin_unlock(&head->lock);
239 } while (--remaining > 0);
240 tcp_port_rover = rover;
241 spin_unlock(&tcp_portalloc_lock);
243 /* Exhausted local port range during search? */
248 /* OK, here is the one we will use. HEAD is
249 * non-NULL and we hold it's mutex.
253 head = &tcp_bhash[tcp_bhashfn(snum)];
254 spin_lock(&head->lock);
255 tb_for_each(tb, node, &head->chain)
256 if (tb->port == snum)
262 if (!hlist_empty(&tb->owners)) {
263 if (sk->sk_reuse > 1)
265 if (tb->fastreuse > 0 &&
266 sk->sk_reuse && sk->sk_state != TCP_LISTEN) {
270 if (tcp_bind_conflict(sk, tb))
276 if (!tb && (tb = tcp_bucket_create(head, snum)) == NULL)
278 if (hlist_empty(&tb->owners)) {
279 if (sk->sk_reuse && sk->sk_state != TCP_LISTEN)
283 } else if (tb->fastreuse &&
284 (!sk->sk_reuse || sk->sk_state == TCP_LISTEN))
287 if (!tcp_sk(sk)->bind_hash)
288 tcp_bind_hash(sk, tb, snum);
289 BUG_TRAP(tcp_sk(sk)->bind_hash == tb);
293 spin_unlock(&head->lock);
299 /* Get rid of any references to a local port held by the
302 static void __tcp_put_port(struct sock *sk)
304 struct inet_opt *inet = inet_sk(sk);
305 struct tcp_bind_hashbucket *head = &tcp_bhash[tcp_bhashfn(inet->num)];
306 struct tcp_bind_bucket *tb;
308 spin_lock(&head->lock);
309 tb = tcp_sk(sk)->bind_hash;
310 __sk_del_bind_node(sk);
311 tcp_sk(sk)->bind_hash = NULL;
313 tcp_bucket_destroy(tb);
314 spin_unlock(&head->lock);
317 void tcp_put_port(struct sock *sk)
324 /* This lock without WQ_FLAG_EXCLUSIVE is good on UP and it can be very bad on SMP.
325 * Look, when several writers sleep and reader wakes them up, all but one
326 * immediately hit write lock and grab all the cpus. Exclusive sleep solves
327 * this, _but_ remember, it adds useless work on UP machines (wake up each
328 * exclusive lock release). It should be ifdefed really.
331 void tcp_listen_wlock(void)
333 write_lock(&tcp_lhash_lock);
335 if (atomic_read(&tcp_lhash_users)) {
339 prepare_to_wait_exclusive(&tcp_lhash_wait,
340 &wait, TASK_UNINTERRUPTIBLE);
341 if (!atomic_read(&tcp_lhash_users))
343 write_unlock_bh(&tcp_lhash_lock);
345 write_lock_bh(&tcp_lhash_lock);
348 finish_wait(&tcp_lhash_wait, &wait);
352 static __inline__ void __tcp_v4_hash(struct sock *sk, const int listen_possible)
354 struct hlist_head *list;
357 BUG_TRAP(sk_unhashed(sk));
358 if (listen_possible && sk->sk_state == TCP_LISTEN) {
359 list = &tcp_listening_hash[tcp_sk_listen_hashfn(sk)];
360 lock = &tcp_lhash_lock;
363 list = &tcp_ehash[(sk->sk_hashent = tcp_sk_hashfn(sk))].chain;
364 lock = &tcp_ehash[sk->sk_hashent].lock;
367 __sk_add_node(sk, list);
368 sock_prot_inc_use(sk->sk_prot);
370 if (listen_possible && sk->sk_state == TCP_LISTEN)
371 wake_up(&tcp_lhash_wait);
374 static void tcp_v4_hash(struct sock *sk)
376 if (sk->sk_state != TCP_CLOSE) {
378 __tcp_v4_hash(sk, 1);
383 void tcp_unhash(struct sock *sk)
390 if (sk->sk_state == TCP_LISTEN) {
393 lock = &tcp_lhash_lock;
395 struct tcp_ehash_bucket *head = &tcp_ehash[sk->sk_hashent];
397 write_lock_bh(&head->lock);
400 if (__sk_del_node_init(sk))
401 sock_prot_dec_use(sk->sk_prot);
402 write_unlock_bh(lock);
405 if (sk->sk_state == TCP_LISTEN)
406 wake_up(&tcp_lhash_wait);
409 /* Don't inline this cruft. Here are some nice properties to
410 * exploit here. The BSD API does not allow a listening TCP
411 * to specify the remote port nor the remote address for the
412 * connection. So always assume those are both wildcarded
413 * during the search since they can never be otherwise.
415 static struct sock *__tcp_v4_lookup_listener(struct hlist_head *head, u32 daddr,
416 unsigned short hnum, int dif)
418 struct sock *result = NULL, *sk;
419 struct hlist_node *node;
423 sk_for_each(sk, node, head) {
424 struct inet_opt *inet = inet_sk(sk);
426 if (inet->num == hnum && !ipv6_only_sock(sk)) {
427 __u32 rcv_saddr = inet->rcv_saddr;
429 score = (sk->sk_family == PF_INET ? 1 : 0);
431 if (rcv_saddr != daddr)
435 if (sk->sk_bound_dev_if) {
436 if (sk->sk_bound_dev_if != dif)
442 if (score > hiscore) {
451 /* Optimize the common listener case. */
452 inline struct sock *tcp_v4_lookup_listener(u32 daddr, unsigned short hnum,
455 struct sock *sk = NULL;
456 struct hlist_head *head;
458 read_lock(&tcp_lhash_lock);
459 head = &tcp_listening_hash[tcp_lhashfn(hnum)];
460 if (!hlist_empty(head)) {
461 struct inet_opt *inet = inet_sk((sk = __sk_head(head)));
462 if (inet->num == hnum && !sk->sk_node.next &&
463 (!inet->rcv_saddr || inet->rcv_saddr == daddr) &&
464 (sk->sk_family == PF_INET || !ipv6_only_sock(sk)) &&
465 !sk->sk_bound_dev_if)
467 sk = __tcp_v4_lookup_listener(head, daddr, hnum, dif);
473 read_unlock(&tcp_lhash_lock);
477 /* Sockets in TCP_CLOSE state are _always_ taken out of the hash, so
478 * we need not check it for TCP lookups anymore, thanks Alexey. -DaveM
480 * Local BH must be disabled here.
483 static inline struct sock *__tcp_v4_lookup_established(u32 saddr, u16 sport,
487 struct tcp_ehash_bucket *head;
488 TCP_V4_ADDR_COOKIE(acookie, saddr, daddr)
489 __u32 ports = TCP_COMBINED_PORTS(sport, hnum);
491 struct hlist_node *node;
492 /* Optimize here for direct hit, only listening connections can
493 * have wildcards anyways.
495 int hash = tcp_hashfn(daddr, hnum, saddr, sport);
496 head = &tcp_ehash[hash];
497 read_lock(&head->lock);
498 sk_for_each(sk, node, &head->chain) {
499 if (TCP_IPV4_MATCH(sk, acookie, saddr, daddr, ports, dif))
500 goto hit; /* You sunk my battleship! */
503 /* Must check for a TIME_WAIT'er before going to listener hash. */
504 sk_for_each(sk, node, &(head + tcp_ehash_size)->chain) {
505 if (TCP_IPV4_TW_MATCH(sk, acookie, saddr, daddr, ports, dif))
510 read_unlock(&head->lock);
517 static inline struct sock *__tcp_v4_lookup(u32 saddr, u16 sport,
518 u32 daddr, u16 hnum, int dif)
520 struct sock *sk = __tcp_v4_lookup_established(saddr, sport,
523 return sk ? : tcp_v4_lookup_listener(daddr, hnum, dif);
526 inline struct sock *tcp_v4_lookup(u32 saddr, u16 sport, u32 daddr,
532 sk = __tcp_v4_lookup(saddr, sport, daddr, ntohs(dport), dif);
538 static inline __u32 tcp_v4_init_sequence(struct sock *sk, struct sk_buff *skb)
540 return secure_tcp_sequence_number(skb->nh.iph->daddr,
546 /* called with local bh disabled */
547 static int __tcp_v4_check_established(struct sock *sk, __u16 lport,
548 struct tcp_tw_bucket **twp)
550 struct inet_opt *inet = inet_sk(sk);
551 u32 daddr = inet->rcv_saddr;
552 u32 saddr = inet->daddr;
553 int dif = sk->sk_bound_dev_if;
554 TCP_V4_ADDR_COOKIE(acookie, saddr, daddr)
555 __u32 ports = TCP_COMBINED_PORTS(inet->dport, lport);
556 int hash = tcp_hashfn(daddr, lport, saddr, inet->dport);
557 struct tcp_ehash_bucket *head = &tcp_ehash[hash];
559 struct hlist_node *node;
560 struct tcp_tw_bucket *tw;
562 write_lock(&head->lock);
564 /* Check TIME-WAIT sockets first. */
565 sk_for_each(sk2, node, &(head + tcp_ehash_size)->chain) {
566 tw = (struct tcp_tw_bucket *)sk2;
568 if (TCP_IPV4_TW_MATCH(sk2, acookie, saddr, daddr, ports, dif)) {
569 struct tcp_opt *tp = tcp_sk(sk);
571 /* With PAWS, it is safe from the viewpoint
572 of data integrity. Even without PAWS it
573 is safe provided sequence spaces do not
574 overlap i.e. at data rates <= 80Mbit/sec.
576 Actually, the idea is close to VJ's one,
577 only timestamp cache is held not per host,
578 but per port pair and TW bucket is used
581 If TW bucket has been already destroyed we
582 fall back to VJ's scheme and use initial
583 timestamp retrieved from peer table.
585 if (tw->tw_ts_recent_stamp &&
586 (!twp || (sysctl_tcp_tw_reuse &&
588 tw->tw_ts_recent_stamp > 1))) {
590 tw->tw_snd_nxt + 65535 + 2) == 0)
592 tp->ts_recent = tw->tw_ts_recent;
593 tp->ts_recent_stamp = tw->tw_ts_recent_stamp;
602 /* And established part... */
603 sk_for_each(sk2, node, &head->chain) {
604 if (TCP_IPV4_MATCH(sk2, acookie, saddr, daddr, ports, dif))
609 /* Must record num and sport now. Otherwise we will see
610 * in hash table socket with a funny identity. */
612 inet->sport = htons(lport);
613 sk->sk_hashent = hash;
614 BUG_TRAP(sk_unhashed(sk));
615 __sk_add_node(sk, &head->chain);
616 sock_prot_inc_use(sk->sk_prot);
617 write_unlock(&head->lock);
621 NET_INC_STATS_BH(LINUX_MIB_TIMEWAITRECYCLED);
623 /* Silly. Should hash-dance instead... */
624 tcp_tw_deschedule(tw);
625 NET_INC_STATS_BH(LINUX_MIB_TIMEWAITRECYCLED);
633 write_unlock(&head->lock);
634 return -EADDRNOTAVAIL;
638 * Bind a port for a connect operation and hash it.
640 static int tcp_v4_hash_connect(struct sock *sk)
642 unsigned short snum = inet_sk(sk)->num;
643 struct tcp_bind_hashbucket *head;
644 struct tcp_bind_bucket *tb;
649 int low = sysctl_local_port_range[0];
650 int high = sysctl_local_port_range[1];
651 int remaining = (high - low) + 1;
652 struct hlist_node *node;
653 struct tcp_tw_bucket *tw = NULL;
657 /* TODO. Actually it is not so bad idea to remove
658 * tcp_portalloc_lock before next submission to Linus.
659 * As soon as we touch this place at all it is time to think.
661 * Now it protects single _advisory_ variable tcp_port_rover,
662 * hence it is mostly useless.
663 * Code will work nicely if we just delete it, but
664 * I am afraid in contented case it will work not better or
665 * even worse: another cpu just will hit the same bucket
667 * So some cpu salt could remove both contention and
668 * memory pingpong. Any ideas how to do this in a nice way?
670 spin_lock(&tcp_portalloc_lock);
671 rover = tcp_port_rover;
675 if ((rover < low) || (rover > high))
677 head = &tcp_bhash[tcp_bhashfn(rover)];
678 spin_lock(&head->lock);
680 /* Does not bother with rcv_saddr checks,
681 * because the established check is already
684 tb_for_each(tb, node, &head->chain) {
685 if (tb->port == rover) {
686 BUG_TRAP(!hlist_empty(&tb->owners));
687 if (tb->fastreuse >= 0)
689 if (!__tcp_v4_check_established(sk,
697 tb = tcp_bucket_create(head, rover);
699 spin_unlock(&head->lock);
706 spin_unlock(&head->lock);
707 } while (--remaining > 0);
708 tcp_port_rover = rover;
709 spin_unlock(&tcp_portalloc_lock);
713 return -EADDRNOTAVAIL;
716 /* All locks still held and bhs disabled */
717 tcp_port_rover = rover;
718 spin_unlock(&tcp_portalloc_lock);
720 tcp_bind_hash(sk, tb, rover);
721 if (sk_unhashed(sk)) {
722 inet_sk(sk)->sport = htons(rover);
723 __tcp_v4_hash(sk, 0);
725 spin_unlock(&head->lock);
728 tcp_tw_deschedule(tw);
736 head = &tcp_bhash[tcp_bhashfn(snum)];
737 tb = tcp_sk(sk)->bind_hash;
738 spin_lock_bh(&head->lock);
739 if (sk_head(&tb->owners) == sk && !sk->sk_bind_node.next) {
740 __tcp_v4_hash(sk, 0);
741 spin_unlock_bh(&head->lock);
744 spin_unlock(&head->lock);
745 /* No definite answer... Walk to established hash table */
746 ret = __tcp_v4_check_established(sk, snum, NULL);
753 /* This will initiate an outgoing connection. */
754 int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
756 struct inet_opt *inet = inet_sk(sk);
757 struct tcp_opt *tp = tcp_sk(sk);
758 struct sockaddr_in *usin = (struct sockaddr_in *)uaddr;
764 if (addr_len < sizeof(struct sockaddr_in))
767 if (usin->sin_family != AF_INET)
768 return -EAFNOSUPPORT;
770 nexthop = daddr = usin->sin_addr.s_addr;
771 if (inet->opt && inet->opt->srr) {
774 nexthop = inet->opt->faddr;
777 tmp = ip_route_connect(&rt, nexthop, inet->saddr,
778 RT_CONN_FLAGS(sk), sk->sk_bound_dev_if,
780 inet->sport, usin->sin_port, sk);
784 if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) {
789 if (!inet->opt || !inet->opt->srr)
793 inet->saddr = rt->rt_src;
794 inet->rcv_saddr = inet->saddr;
796 if (tp->ts_recent_stamp && inet->daddr != daddr) {
797 /* Reset inherited state */
799 tp->ts_recent_stamp = 0;
803 if (sysctl_tcp_tw_recycle &&
804 !tp->ts_recent_stamp && rt->rt_dst == daddr) {
805 struct inet_peer *peer = rt_get_peer(rt);
807 /* VJ's idea. We save last timestamp seen from
808 * the destination in peer table, when entering state TIME-WAIT
809 * and initialize ts_recent from it, when trying new connection.
812 if (peer && peer->tcp_ts_stamp + TCP_PAWS_MSL >= xtime.tv_sec) {
813 tp->ts_recent_stamp = peer->tcp_ts_stamp;
814 tp->ts_recent = peer->tcp_ts;
818 inet->dport = usin->sin_port;
821 tp->ext_header_len = 0;
823 tp->ext_header_len = inet->opt->optlen;
827 /* Socket identity is still unknown (sport may be zero).
828 * However we set state to SYN-SENT and not releasing socket
829 * lock select source port, enter ourselves into the hash tables and
830 * complete initialization after this.
832 tcp_set_state(sk, TCP_SYN_SENT);
833 err = tcp_v4_hash_connect(sk);
837 err = ip_route_newports(&rt, inet->sport, inet->dport, sk);
841 /* OK, now commit destination to socket. */
842 __sk_dst_set(sk, &rt->u.dst);
843 tcp_v4_setup_caps(sk, &rt->u.dst);
844 tp->ext2_header_len = rt->u.dst.header_len;
847 tp->write_seq = secure_tcp_sequence_number(inet->saddr,
852 inet->id = tp->write_seq ^ jiffies;
854 err = tcp_connect(sk);
862 /* This unhashes the socket and releases the local port, if necessary. */
863 tcp_set_state(sk, TCP_CLOSE);
865 sk->sk_route_caps = 0;
870 static __inline__ int tcp_v4_iif(struct sk_buff *skb)
872 return ((struct rtable *)skb->dst)->rt_iif;
875 static __inline__ u32 tcp_v4_synq_hash(u32 raddr, u16 rport, u32 rnd)
877 return (jhash_2words(raddr, (u32) rport, rnd) & (TCP_SYNQ_HSIZE - 1));
880 static struct open_request *tcp_v4_search_req(struct tcp_opt *tp,
881 struct open_request ***prevp,
883 __u32 raddr, __u32 laddr)
885 struct tcp_listen_opt *lopt = tp->listen_opt;
886 struct open_request *req, **prev;
888 for (prev = &lopt->syn_table[tcp_v4_synq_hash(raddr, rport, lopt->hash_rnd)];
889 (req = *prev) != NULL;
890 prev = &req->dl_next) {
891 if (req->rmt_port == rport &&
892 req->af.v4_req.rmt_addr == raddr &&
893 req->af.v4_req.loc_addr == laddr &&
894 TCP_INET_FAMILY(req->class->family)) {
904 static void tcp_v4_synq_add(struct sock *sk, struct open_request *req)
906 struct tcp_opt *tp = tcp_sk(sk);
907 struct tcp_listen_opt *lopt = tp->listen_opt;
908 u32 h = tcp_v4_synq_hash(req->af.v4_req.rmt_addr, req->rmt_port, lopt->hash_rnd);
910 req->expires = jiffies + TCP_TIMEOUT_INIT;
913 req->dl_next = lopt->syn_table[h];
915 write_lock(&tp->syn_wait_lock);
916 lopt->syn_table[h] = req;
917 write_unlock(&tp->syn_wait_lock);
919 #ifdef CONFIG_ACCEPT_QUEUES
920 tcp_synq_added(sk, req);
928 * This routine does path mtu discovery as defined in RFC1191.
930 static inline void do_pmtu_discovery(struct sock *sk, struct iphdr *iph,
933 struct dst_entry *dst;
934 struct inet_opt *inet = inet_sk(sk);
935 struct tcp_opt *tp = tcp_sk(sk);
937 /* We are not interested in TCP_LISTEN and open_requests (SYN-ACKs
938 * send out by Linux are always <576bytes so they should go through
941 if (sk->sk_state == TCP_LISTEN)
944 /* We don't check in the destentry if pmtu discovery is forbidden
945 * on this route. We just assume that no packet_to_big packets
946 * are send back when pmtu discovery is not active.
947 * There is a small race when the user changes this flag in the
948 * route, but I think that's acceptable.
950 if ((dst = __sk_dst_check(sk, 0)) == NULL)
953 dst->ops->update_pmtu(dst, mtu);
955 /* Something is about to be wrong... Remember soft error
956 * for the case, if this connection will not able to recover.
958 if (mtu < dst_pmtu(dst) && ip_dont_fragment(sk, dst))
959 sk->sk_err_soft = EMSGSIZE;
963 if (inet->pmtudisc != IP_PMTUDISC_DONT &&
964 tp->pmtu_cookie > mtu) {
965 tcp_sync_mss(sk, mtu);
967 /* Resend the TCP packet because it's
968 * clear that the old packet has been
969 * dropped. This is the new "fast" path mtu
972 tcp_simple_retransmit(sk);
973 } /* else let the usual retransmit timer handle it */
977 * This routine is called by the ICMP module when it gets some
978 * sort of error condition. If err < 0 then the socket should
979 * be closed and the error returned to the user. If err > 0
980 * it's just the icmp type << 8 | icmp code. After adjustment
981 * header points to the first 8 bytes of the tcp header. We need
982 * to find the appropriate port.
984 * The locking strategy used here is very "optimistic". When
985 * someone else accesses the socket the ICMP is just dropped
986 * and for some paths there is no check at all.
987 * A more general error queue to queue errors for later handling
988 * is probably better.
992 void tcp_v4_err(struct sk_buff *skb, u32 info)
994 struct iphdr *iph = (struct iphdr *)skb->data;
995 struct tcphdr *th = (struct tcphdr *)(skb->data + (iph->ihl << 2));
997 struct inet_opt *inet;
998 int type = skb->h.icmph->type;
999 int code = skb->h.icmph->code;
1004 if (skb->len < (iph->ihl << 2) + 8) {
1005 ICMP_INC_STATS_BH(ICMP_MIB_INERRORS);
1009 sk = tcp_v4_lookup(iph->daddr, th->dest, iph->saddr,
1010 th->source, tcp_v4_iif(skb));
1012 ICMP_INC_STATS_BH(ICMP_MIB_INERRORS);
1015 if (sk->sk_state == TCP_TIME_WAIT) {
1016 tcp_tw_put((struct tcp_tw_bucket *)sk);
1021 /* If too many ICMPs get dropped on busy
1022 * servers this needs to be solved differently.
1024 if (sock_owned_by_user(sk))
1025 NET_INC_STATS_BH(LINUX_MIB_LOCKDROPPEDICMPS);
1027 if (sk->sk_state == TCP_CLOSE)
1031 seq = ntohl(th->seq);
1032 if (sk->sk_state != TCP_LISTEN &&
1033 !between(seq, tp->snd_una, tp->snd_nxt)) {
1034 NET_INC_STATS(LINUX_MIB_OUTOFWINDOWICMPS);
1039 case ICMP_SOURCE_QUENCH:
1040 /* Just silently ignore these. */
1042 case ICMP_PARAMETERPROB:
1045 case ICMP_DEST_UNREACH:
1046 if (code > NR_ICMP_UNREACH)
1049 if (code == ICMP_FRAG_NEEDED) { /* PMTU discovery (RFC1191) */
1050 if (!sock_owned_by_user(sk))
1051 do_pmtu_discovery(sk, iph, info);
1055 err = icmp_err_convert[code].errno;
1057 case ICMP_TIME_EXCEEDED:
1064 switch (sk->sk_state) {
1065 struct open_request *req, **prev;
1067 if (sock_owned_by_user(sk))
1070 req = tcp_v4_search_req(tp, &prev, th->dest,
1071 iph->daddr, iph->saddr);
1075 /* ICMPs are not backlogged, hence we cannot get
1076 an established socket here.
1080 if (seq != req->snt_isn) {
1081 NET_INC_STATS_BH(LINUX_MIB_OUTOFWINDOWICMPS);
1086 * Still in SYN_RECV, just remove it silently.
1087 * There is no good way to pass the error to the newly
1088 * created socket, and POSIX does not want network
1089 * errors returned from accept().
1091 tcp_synq_drop(sk, req, prev);
1095 case TCP_SYN_RECV: /* Cannot happen.
1096 It can f.e. if SYNs crossed.
1098 if (!sock_owned_by_user(sk)) {
1099 TCP_INC_STATS_BH(TCP_MIB_ATTEMPTFAILS);
1102 sk->sk_error_report(sk);
1106 sk->sk_err_soft = err;
1111 /* If we've already connected we will keep trying
1112 * until we time out, or the user gives up.
1114 * rfc1122 4.2.3.9 allows to consider as hard errors
1115 * only PROTO_UNREACH and PORT_UNREACH (well, FRAG_FAILED too,
1116 * but it is obsoleted by pmtu discovery).
1118 * Note, that in modern internet, where routing is unreliable
1119 * and in each dark corner broken firewalls sit, sending random
1120 * errors ordered by their masters even this two messages finally lose
1121 * their original sense (even Linux sends invalid PORT_UNREACHs)
1123 * Now we are in compliance with RFCs.
1128 if (!sock_owned_by_user(sk) && inet->recverr) {
1130 sk->sk_error_report(sk);
1131 } else { /* Only an error on timeout */
1132 sk->sk_err_soft = err;
1140 /* This routine computes an IPv4 TCP checksum. */
1141 void tcp_v4_send_check(struct sock *sk, struct tcphdr *th, int len,
1142 struct sk_buff *skb)
1144 struct inet_opt *inet = inet_sk(sk);
1146 if (skb->ip_summed == CHECKSUM_HW) {
1147 th->check = ~tcp_v4_check(th, len, inet->saddr, inet->daddr, 0);
1148 skb->csum = offsetof(struct tcphdr, check);
1150 th->check = tcp_v4_check(th, len, inet->saddr, inet->daddr,
1151 csum_partial((char *)th,
1158 * This routine will send an RST to the other tcp.
1160 * Someone asks: why I NEVER use socket parameters (TOS, TTL etc.)
1162 * Answer: if a packet caused RST, it is not for a socket
1163 * existing in our system, if it is matched to a socket,
1164 * it is just duplicate segment or bug in other side's TCP.
1165 * So that we build reply only basing on parameters
1166 * arrived with segment.
1167 * Exception: precedence violation. We do not implement it in any case.
1170 static void tcp_v4_send_reset(struct sk_buff *skb)
1172 struct tcphdr *th = skb->h.th;
1174 struct ip_reply_arg arg;
1176 /* Never send a reset in response to a reset. */
1180 if (((struct rtable *)skb->dst)->rt_type != RTN_LOCAL)
1183 /* Swap the send and the receive. */
1184 memset(&rth, 0, sizeof(struct tcphdr));
1185 rth.dest = th->source;
1186 rth.source = th->dest;
1187 rth.doff = sizeof(struct tcphdr) / 4;
1191 rth.seq = th->ack_seq;
1194 rth.ack_seq = htonl(ntohl(th->seq) + th->syn + th->fin +
1195 skb->len - (th->doff << 2));
1198 memset(&arg, 0, sizeof arg);
1199 arg.iov[0].iov_base = (unsigned char *)&rth;
1200 arg.iov[0].iov_len = sizeof rth;
1201 arg.csum = csum_tcpudp_nofold(skb->nh.iph->daddr,
1202 skb->nh.iph->saddr, /*XXX*/
1203 sizeof(struct tcphdr), IPPROTO_TCP, 0);
1204 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
1206 ip_send_reply(tcp_socket->sk, skb, &arg, sizeof rth);
1208 TCP_INC_STATS_BH(TCP_MIB_OUTSEGS);
1209 TCP_INC_STATS_BH(TCP_MIB_OUTRSTS);
1212 /* The code following below sending ACKs in SYN-RECV and TIME-WAIT states
1213 outside socket context is ugly, certainly. What can I do?
1216 static void tcp_v4_send_ack(struct sk_buff *skb, u32 seq, u32 ack,
1219 struct tcphdr *th = skb->h.th;
1224 struct ip_reply_arg arg;
1226 memset(&rep.th, 0, sizeof(struct tcphdr));
1227 memset(&arg, 0, sizeof arg);
1229 arg.iov[0].iov_base = (unsigned char *)&rep;
1230 arg.iov[0].iov_len = sizeof(rep.th);
1232 rep.tsopt[0] = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
1233 (TCPOPT_TIMESTAMP << 8) |
1235 rep.tsopt[1] = htonl(tcp_time_stamp);
1236 rep.tsopt[2] = htonl(ts);
1237 arg.iov[0].iov_len = sizeof(rep);
1240 /* Swap the send and the receive. */
1241 rep.th.dest = th->source;
1242 rep.th.source = th->dest;
1243 rep.th.doff = arg.iov[0].iov_len / 4;
1244 rep.th.seq = htonl(seq);
1245 rep.th.ack_seq = htonl(ack);
1247 rep.th.window = htons(win);
1249 arg.csum = csum_tcpudp_nofold(skb->nh.iph->daddr,
1250 skb->nh.iph->saddr, /*XXX*/
1251 arg.iov[0].iov_len, IPPROTO_TCP, 0);
1252 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
1254 ip_send_reply(tcp_socket->sk, skb, &arg, arg.iov[0].iov_len);
1256 TCP_INC_STATS_BH(TCP_MIB_OUTSEGS);
1259 static void tcp_v4_timewait_ack(struct sock *sk, struct sk_buff *skb)
1261 struct tcp_tw_bucket *tw = (struct tcp_tw_bucket *)sk;
1263 tcp_v4_send_ack(skb, tw->tw_snd_nxt, tw->tw_rcv_nxt,
1264 tw->tw_rcv_wnd >> tw->tw_rcv_wscale, tw->tw_ts_recent);
1269 static void tcp_v4_or_send_ack(struct sk_buff *skb, struct open_request *req)
1271 tcp_v4_send_ack(skb, req->snt_isn + 1, req->rcv_isn + 1, req->rcv_wnd,
1275 static struct dst_entry* tcp_v4_route_req(struct sock *sk,
1276 struct open_request *req)
1279 struct ip_options *opt = req->af.v4_req.opt;
1280 struct flowi fl = { .oif = sk->sk_bound_dev_if,
1282 { .daddr = ((opt && opt->srr) ?
1284 req->af.v4_req.rmt_addr),
1285 .saddr = req->af.v4_req.loc_addr,
1286 .tos = RT_CONN_FLAGS(sk) } },
1287 .proto = IPPROTO_TCP,
1289 { .sport = inet_sk(sk)->sport,
1290 .dport = req->rmt_port } } };
1292 if (ip_route_output_flow(&rt, &fl, sk, 0)) {
1293 IP_INC_STATS_BH(IPSTATS_MIB_OUTNOROUTES);
1296 if (opt && opt->is_strictroute && rt->rt_dst != rt->rt_gateway) {
1298 IP_INC_STATS_BH(IPSTATS_MIB_OUTNOROUTES);
1305 * Send a SYN-ACK after having received an ACK.
1306 * This still operates on a open_request only, not on a big
1309 static int tcp_v4_send_synack(struct sock *sk, struct open_request *req,
1310 struct dst_entry *dst)
1313 struct sk_buff * skb;
1315 /* First, grab a route. */
1316 if (!dst && (dst = tcp_v4_route_req(sk, req)) == NULL)
1319 skb = tcp_make_synack(sk, dst, req);
1322 struct tcphdr *th = skb->h.th;
1324 th->check = tcp_v4_check(th, skb->len,
1325 req->af.v4_req.loc_addr,
1326 req->af.v4_req.rmt_addr,
1327 csum_partial((char *)th, skb->len,
1330 err = ip_build_and_send_pkt(skb, sk, req->af.v4_req.loc_addr,
1331 req->af.v4_req.rmt_addr,
1332 req->af.v4_req.opt);
1333 if (err == NET_XMIT_CN)
1343 * IPv4 open_request destructor.
1345 static void tcp_v4_or_free(struct open_request *req)
1347 if (req->af.v4_req.opt)
1348 kfree(req->af.v4_req.opt);
1351 static inline void syn_flood_warning(struct sk_buff *skb)
1353 static unsigned long warntime;
1355 if (time_after(jiffies, (warntime + HZ * 60))) {
1358 "possible SYN flooding on port %d. Sending cookies.\n",
1359 ntohs(skb->h.th->dest));
1364 * Save and compile IPv4 options into the open_request if needed.
1366 static inline struct ip_options *tcp_v4_save_options(struct sock *sk,
1367 struct sk_buff *skb)
1369 struct ip_options *opt = &(IPCB(skb)->opt);
1370 struct ip_options *dopt = NULL;
1372 if (opt && opt->optlen) {
1373 int opt_size = optlength(opt);
1374 dopt = kmalloc(opt_size, GFP_ATOMIC);
1376 if (ip_options_echo(dopt, skb)) {
1386 * Maximum number of SYN_RECV sockets in queue per LISTEN socket.
1387 * One SYN_RECV socket costs about 80bytes on a 32bit machine.
1388 * It would be better to replace it with a global counter for all sockets
1389 * but then some measure against one socket starving all other sockets
1392 * It was 128 by default. Experiments with real servers show, that
1393 * it is absolutely not enough even at 100conn/sec. 256 cures most
1394 * of problems. This value is adjusted to 128 for very small machines
1395 * (<=32Mb of memory) and to 1024 on normal or better ones (>=256Mb).
1396 * Further increasing requires to change hash table size.
1398 int sysctl_max_syn_backlog = 256;
1400 struct or_calltable or_ipv4 = {
1402 .rtx_syn_ack = tcp_v4_send_synack,
1403 .send_ack = tcp_v4_or_send_ack,
1404 .destructor = tcp_v4_or_free,
1405 .send_reset = tcp_v4_send_reset,
1408 int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
1411 struct open_request *req;
1412 __u32 saddr = skb->nh.iph->saddr;
1413 __u32 daddr = skb->nh.iph->daddr;
1414 __u32 isn = TCP_SKB_CB(skb)->when;
1415 struct dst_entry *dst = NULL;
1416 #ifdef CONFIG_ACCEPT_QUEUES
1419 #ifdef CONFIG_SYN_COOKIES
1420 int want_cookie = 0;
1422 #define want_cookie 0 /* Argh, why doesn't gcc optimize this :( */
1425 /* Never answer to SYNs send to broadcast or multicast */
1426 if (((struct rtable *)skb->dst)->rt_flags &
1427 (RTCF_BROADCAST | RTCF_MULTICAST))
1430 /* TW buckets are converted to open requests without
1431 * limitations, they conserve resources and peer is
1432 * evidently real one.
1434 if (tcp_synq_is_full(sk) && !isn) {
1435 #ifdef CONFIG_SYN_COOKIES
1436 if (sysctl_tcp_syncookies) {
1443 #ifdef CONFIG_ACCEPT_QUEUES
1444 class = (skb->nfmark <= 0) ? 0 :
1445 ((skb->nfmark >= NUM_ACCEPT_QUEUES) ? 0: skb->nfmark);
1447 * Accept only if the class has shares set or if the default class
1448 * i.e. class 0 has shares
1450 if (!(tcp_sk(sk)->acceptq[class].aq_ratio)) {
1451 if (tcp_sk(sk)->acceptq[0].aq_ratio)
1458 /* Accept backlog is full. If we have already queued enough
1459 * of warm entries in syn queue, drop request. It is better than
1460 * clogging syn queue with openreqs with exponentially increasing
1463 #ifdef CONFIG_ACCEPT_QUEUES
1464 if (sk_acceptq_is_full(sk, class) && tcp_synq_young(sk, class) > 1)
1466 if (sk_acceptq_is_full(sk) && tcp_synq_young(sk) > 1)
1470 req = tcp_openreq_alloc();
1474 tcp_clear_options(&tp);
1476 tp.user_mss = tcp_sk(sk)->user_mss;
1478 tcp_parse_options(skb, &tp, 0);
1481 tcp_clear_options(&tp);
1485 if (tp.saw_tstamp && !tp.rcv_tsval) {
1486 /* Some OSes (unknown ones, but I see them on web server, which
1487 * contains information interesting only for windows'
1488 * users) do not send their stamp in SYN. It is easy case.
1489 * We simply do not advertise TS support.
1494 tp.tstamp_ok = tp.saw_tstamp;
1496 tcp_openreq_init(req, &tp, skb);
1497 #ifdef CONFIG_ACCEPT_QUEUES
1498 req->acceptq_class = class;
1499 req->acceptq_time_stamp = jiffies;
1501 req->af.v4_req.loc_addr = daddr;
1502 req->af.v4_req.rmt_addr = saddr;
1503 req->af.v4_req.opt = tcp_v4_save_options(sk, skb);
1504 req->class = &or_ipv4;
1506 TCP_ECN_create_request(req, skb->h.th);
1509 #ifdef CONFIG_SYN_COOKIES
1510 syn_flood_warning(skb);
1512 isn = cookie_v4_init_sequence(sk, skb, &req->mss);
1514 struct inet_peer *peer = NULL;
1516 /* VJ's idea. We save last timestamp seen
1517 * from the destination in peer table, when entering
1518 * state TIME-WAIT, and check against it before
1519 * accepting new connection request.
1521 * If "isn" is not zero, this request hit alive
1522 * timewait bucket, so that all the necessary checks
1523 * are made in the function processing timewait state.
1525 if (tp.saw_tstamp &&
1526 sysctl_tcp_tw_recycle &&
1527 (dst = tcp_v4_route_req(sk, req)) != NULL &&
1528 (peer = rt_get_peer((struct rtable *)dst)) != NULL &&
1529 peer->v4daddr == saddr) {
1530 if (xtime.tv_sec < peer->tcp_ts_stamp + TCP_PAWS_MSL &&
1531 (s32)(peer->tcp_ts - req->ts_recent) >
1533 NET_INC_STATS_BH(LINUX_MIB_PAWSPASSIVEREJECTED);
1538 /* Kill the following clause, if you dislike this way. */
1539 else if (!sysctl_tcp_syncookies &&
1540 (sysctl_max_syn_backlog - tcp_synq_len(sk) <
1541 (sysctl_max_syn_backlog >> 2)) &&
1542 (!peer || !peer->tcp_ts_stamp) &&
1543 (!dst || !dst_metric(dst, RTAX_RTT))) {
1544 /* Without syncookies last quarter of
1545 * backlog is filled with destinations,
1546 * proven to be alive.
1547 * It means that we continue to communicate
1548 * to destinations, already remembered
1549 * to the moment of synflood.
1551 NETDEBUG(if (net_ratelimit()) \
1552 printk(KERN_DEBUG "TCP: drop open "
1553 "request from %u.%u."
1556 ntohs(skb->h.th->source)));
1561 isn = tcp_v4_init_sequence(sk, skb);
1565 if (tcp_v4_send_synack(sk, req, dst))
1569 tcp_openreq_free(req);
1571 tcp_v4_synq_add(sk, req);
1576 tcp_openreq_free(req);
1578 TCP_INC_STATS_BH(TCP_MIB_ATTEMPTFAILS);
1584 * The three way handshake has completed - we got a valid synack -
1585 * now create the new socket.
1587 struct sock *tcp_v4_syn_recv_sock(struct sock *sk, struct sk_buff *skb,
1588 struct open_request *req,
1589 struct dst_entry *dst)
1591 struct inet_opt *newinet;
1592 struct tcp_opt *newtp;
1595 #ifdef CONFIG_ACCEPT_QUEUES
1596 if (sk_acceptq_is_full(sk, req->acceptq_class))
1598 if (sk_acceptq_is_full(sk))
1602 if (!dst && (dst = tcp_v4_route_req(sk, req)) == NULL)
1605 newsk = tcp_create_openreq_child(sk, req, skb);
1609 newsk->sk_dst_cache = dst;
1610 tcp_v4_setup_caps(newsk, dst);
1612 newtp = tcp_sk(newsk);
1613 newinet = inet_sk(newsk);
1614 newinet->daddr = req->af.v4_req.rmt_addr;
1615 newinet->rcv_saddr = req->af.v4_req.loc_addr;
1616 newinet->saddr = req->af.v4_req.loc_addr;
1617 newinet->opt = req->af.v4_req.opt;
1618 req->af.v4_req.opt = NULL;
1619 newinet->mc_index = tcp_v4_iif(skb);
1620 newinet->mc_ttl = skb->nh.iph->ttl;
1621 newtp->ext_header_len = 0;
1623 newtp->ext_header_len = newinet->opt->optlen;
1624 newtp->ext2_header_len = dst->header_len;
1625 newinet->id = newtp->write_seq ^ jiffies;
1627 tcp_sync_mss(newsk, dst_pmtu(dst));
1628 newtp->advmss = dst_metric(dst, RTAX_ADVMSS);
1629 tcp_initialize_rcv_mss(newsk);
1631 __tcp_v4_hash(newsk, 0);
1632 __tcp_inherit_port(sk, newsk);
1637 NET_INC_STATS_BH(LINUX_MIB_LISTENOVERFLOWS);
1639 NET_INC_STATS_BH(LINUX_MIB_LISTENDROPS);
1644 static struct sock *tcp_v4_hnd_req(struct sock *sk, struct sk_buff *skb)
1646 struct tcphdr *th = skb->h.th;
1647 struct iphdr *iph = skb->nh.iph;
1648 struct tcp_opt *tp = tcp_sk(sk);
1650 struct open_request **prev;
1651 /* Find possible connection requests. */
1652 struct open_request *req = tcp_v4_search_req(tp, &prev, th->source,
1653 iph->saddr, iph->daddr);
1655 return tcp_check_req(sk, skb, req, prev);
1657 nsk = __tcp_v4_lookup_established(skb->nh.iph->saddr,
1664 if (nsk->sk_state != TCP_TIME_WAIT) {
1668 tcp_tw_put((struct tcp_tw_bucket *)nsk);
1672 #ifdef CONFIG_SYN_COOKIES
1673 if (!th->rst && !th->syn && th->ack)
1674 sk = cookie_v4_check(sk, skb, &(IPCB(skb)->opt));
1679 static int tcp_v4_checksum_init(struct sk_buff *skb)
1681 if (skb->ip_summed == CHECKSUM_HW) {
1682 skb->ip_summed = CHECKSUM_UNNECESSARY;
1683 if (!tcp_v4_check(skb->h.th, skb->len, skb->nh.iph->saddr,
1684 skb->nh.iph->daddr, skb->csum))
1687 NETDEBUG(if (net_ratelimit())
1688 printk(KERN_DEBUG "hw tcp v4 csum failed\n"));
1689 skb->ip_summed = CHECKSUM_NONE;
1691 if (skb->len <= 76) {
1692 if (tcp_v4_check(skb->h.th, skb->len, skb->nh.iph->saddr,
1694 skb_checksum(skb, 0, skb->len, 0)))
1696 skb->ip_summed = CHECKSUM_UNNECESSARY;
1698 skb->csum = ~tcp_v4_check(skb->h.th, skb->len,
1700 skb->nh.iph->daddr, 0);
1706 /* The socket must have it's spinlock held when we get
1709 * We have a potential double-lock case here, so even when
1710 * doing backlog processing we use the BH locking scheme.
1711 * This is because we cannot sleep with the original spinlock
1714 int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
1716 if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
1717 TCP_CHECK_TIMER(sk);
1718 if (tcp_rcv_established(sk, skb, skb->h.th, skb->len))
1720 TCP_CHECK_TIMER(sk);
1724 if (skb->len < (skb->h.th->doff << 2) || tcp_checksum_complete(skb))
1727 if (sk->sk_state == TCP_LISTEN) {
1728 struct sock *nsk = tcp_v4_hnd_req(sk, skb);
1733 if (tcp_child_process(sk, nsk, skb))
1739 TCP_CHECK_TIMER(sk);
1740 if (tcp_rcv_state_process(sk, skb, skb->h.th, skb->len))
1742 TCP_CHECK_TIMER(sk);
1746 tcp_v4_send_reset(skb);
1749 /* Be careful here. If this function gets more complicated and
1750 * gcc suffers from register pressure on the x86, sk (in %ebx)
1751 * might be destroyed here. This current version compiles correctly,
1752 * but you have been warned.
1757 TCP_INC_STATS_BH(TCP_MIB_INERRS);
1765 int tcp_v4_rcv(struct sk_buff *skb)
1771 if (skb->pkt_type != PACKET_HOST)
1774 /* Count it even if it's bad */
1775 TCP_INC_STATS_BH(TCP_MIB_INSEGS);
1777 if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
1782 if (th->doff < sizeof(struct tcphdr) / 4)
1784 if (!pskb_may_pull(skb, th->doff * 4))
1787 /* An explanation is required here, I think.
1788 * Packet length and doff are validated by header prediction,
1789 * provided case of th->doff==0 is elimineted.
1790 * So, we defer the checks. */
1791 if ((skb->ip_summed != CHECKSUM_UNNECESSARY &&
1792 tcp_v4_checksum_init(skb) < 0))
1796 TCP_SKB_CB(skb)->seq = ntohl(th->seq);
1797 TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
1798 skb->len - th->doff * 4);
1799 TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
1800 TCP_SKB_CB(skb)->when = 0;
1801 TCP_SKB_CB(skb)->flags = skb->nh.iph->tos;
1802 TCP_SKB_CB(skb)->sacked = 0;
1804 sk = __tcp_v4_lookup(skb->nh.iph->saddr, th->source,
1805 skb->nh.iph->daddr, ntohs(th->dest),
1812 #if defined(CONFIG_VNET) || defined(CONFIG_VNET_MODULE)
1813 /* Silently drop if VNET is active and the context is not
1814 * entitled to read the packet.
1817 /* Transfer ownership of reusable TIME_WAIT buckets to
1818 * whomever VNET decided should own the packet.
1820 if (sk->sk_state == TCP_TIME_WAIT)
1821 sk->sk_xid = skb->xid;
1823 if ((int) sk->sk_xid > 0 && sk->sk_xid != skb->xid)
1828 if (sk->sk_state == TCP_TIME_WAIT)
1831 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
1832 goto discard_and_relse;
1834 if (sk_filter(sk, skb, 0))
1835 goto discard_and_relse;
1841 if (!sock_owned_by_user(sk)) {
1842 if (!tcp_prequeue(sk, skb))
1843 ret = tcp_v4_do_rcv(sk, skb);
1845 sk_add_backlog(sk, skb);
1853 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
1856 if (skb->len < (th->doff << 2) || tcp_checksum_complete(skb)) {
1858 TCP_INC_STATS_BH(TCP_MIB_INERRS);
1859 #if defined(CONFIG_VNET) || defined(CONFIG_VNET_MODULE)
1860 } else if (vnet_active && skb->sk) {
1861 /* VNET: Suppress RST if the port was bound to a (presumably raw) socket */
1864 tcp_v4_send_reset(skb);
1868 /* Discard frame. */
1877 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
1878 tcp_tw_put((struct tcp_tw_bucket *) sk);
1882 if (skb->len < (th->doff << 2) || tcp_checksum_complete(skb)) {
1883 TCP_INC_STATS_BH(TCP_MIB_INERRS);
1884 tcp_tw_put((struct tcp_tw_bucket *) sk);
1887 switch (tcp_timewait_state_process((struct tcp_tw_bucket *)sk,
1888 skb, th, skb->len)) {
1890 struct sock *sk2 = tcp_v4_lookup_listener(skb->nh.iph->daddr,
1894 tcp_tw_deschedule((struct tcp_tw_bucket *)sk);
1895 tcp_tw_put((struct tcp_tw_bucket *)sk);
1899 /* Fall through to ACK */
1902 tcp_v4_timewait_ack(sk, skb);
1906 case TCP_TW_SUCCESS:;
1911 /* With per-bucket locks this operation is not-atomic, so that
1912 * this version is not worse.
1914 static void __tcp_v4_rehash(struct sock *sk)
1916 sk->sk_prot->unhash(sk);
1917 sk->sk_prot->hash(sk);
1920 static int tcp_v4_reselect_saddr(struct sock *sk)
1922 struct inet_opt *inet = inet_sk(sk);
1925 __u32 old_saddr = inet->saddr;
1927 __u32 daddr = inet->daddr;
1929 if (inet->opt && inet->opt->srr)
1930 daddr = inet->opt->faddr;
1932 /* Query new route. */
1933 err = ip_route_connect(&rt, daddr, 0,
1934 RT_TOS(inet->tos) | sk->sk_localroute,
1935 sk->sk_bound_dev_if,
1937 inet->sport, inet->dport, sk);
1941 __sk_dst_set(sk, &rt->u.dst);
1942 tcp_v4_setup_caps(sk, &rt->u.dst);
1943 tcp_sk(sk)->ext2_header_len = rt->u.dst.header_len;
1945 new_saddr = rt->rt_src;
1947 if (new_saddr == old_saddr)
1950 if (sysctl_ip_dynaddr > 1) {
1951 printk(KERN_INFO "tcp_v4_rebuild_header(): shifting inet->"
1952 "saddr from %d.%d.%d.%d to %d.%d.%d.%d\n",
1954 NIPQUAD(new_saddr));
1957 inet->saddr = new_saddr;
1958 inet->rcv_saddr = new_saddr;
1960 /* XXX The only one ugly spot where we need to
1961 * XXX really change the sockets identity after
1962 * XXX it has entered the hashes. -DaveM
1964 * Besides that, it does not check for connection
1965 * uniqueness. Wait for troubles.
1967 __tcp_v4_rehash(sk);
1971 int tcp_v4_rebuild_header(struct sock *sk)
1973 struct inet_opt *inet = inet_sk(sk);
1974 struct rtable *rt = (struct rtable *)__sk_dst_check(sk, 0);
1978 /* Route is OK, nothing to do. */
1983 daddr = inet->daddr;
1984 if (inet->opt && inet->opt->srr)
1985 daddr = inet->opt->faddr;
1988 struct flowi fl = { .oif = sk->sk_bound_dev_if,
1991 .saddr = inet->saddr,
1992 .tos = RT_CONN_FLAGS(sk) } },
1993 .proto = IPPROTO_TCP,
1995 { .sport = inet->sport,
1996 .dport = inet->dport } } };
1998 err = ip_route_output_flow(&rt, &fl, sk, 0);
2001 __sk_dst_set(sk, &rt->u.dst);
2002 tcp_v4_setup_caps(sk, &rt->u.dst);
2003 tcp_sk(sk)->ext2_header_len = rt->u.dst.header_len;
2007 /* Routing failed... */
2008 sk->sk_route_caps = 0;
2010 if (!sysctl_ip_dynaddr ||
2011 sk->sk_state != TCP_SYN_SENT ||
2012 (sk->sk_userlocks & SOCK_BINDADDR_LOCK) ||
2013 (err = tcp_v4_reselect_saddr(sk)) != 0)
2014 sk->sk_err_soft = -err;
2019 static void v4_addr2sockaddr(struct sock *sk, struct sockaddr * uaddr)
2021 struct sockaddr_in *sin = (struct sockaddr_in *) uaddr;
2022 struct inet_opt *inet = inet_sk(sk);
2024 sin->sin_family = AF_INET;
2025 sin->sin_addr.s_addr = inet->daddr;
2026 sin->sin_port = inet->dport;
2029 /* VJ's idea. Save last timestamp seen from this destination
2030 * and hold it at least for normal timewait interval to use for duplicate
2031 * segment detection in subsequent connections, before they enter synchronized
2035 int tcp_v4_remember_stamp(struct sock *sk)
2037 struct inet_opt *inet = inet_sk(sk);
2038 struct tcp_opt *tp = tcp_sk(sk);
2039 struct rtable *rt = (struct rtable *)__sk_dst_get(sk);
2040 struct inet_peer *peer = NULL;
2043 if (!rt || rt->rt_dst != inet->daddr) {
2044 peer = inet_getpeer(inet->daddr, 1);
2048 rt_bind_peer(rt, 1);
2053 if ((s32)(peer->tcp_ts - tp->ts_recent) <= 0 ||
2054 (peer->tcp_ts_stamp + TCP_PAWS_MSL < xtime.tv_sec &&
2055 peer->tcp_ts_stamp <= tp->ts_recent_stamp)) {
2056 peer->tcp_ts_stamp = tp->ts_recent_stamp;
2057 peer->tcp_ts = tp->ts_recent;
2067 int tcp_v4_tw_remember_stamp(struct tcp_tw_bucket *tw)
2069 struct inet_peer *peer = NULL;
2071 peer = inet_getpeer(tw->tw_daddr, 1);
2074 if ((s32)(peer->tcp_ts - tw->tw_ts_recent) <= 0 ||
2075 (peer->tcp_ts_stamp + TCP_PAWS_MSL < xtime.tv_sec &&
2076 peer->tcp_ts_stamp <= tw->tw_ts_recent_stamp)) {
2077 peer->tcp_ts_stamp = tw->tw_ts_recent_stamp;
2078 peer->tcp_ts = tw->tw_ts_recent;
2087 struct tcp_func ipv4_specific = {
2088 .queue_xmit = ip_queue_xmit,
2089 .send_check = tcp_v4_send_check,
2090 .rebuild_header = tcp_v4_rebuild_header,
2091 .conn_request = tcp_v4_conn_request,
2092 .syn_recv_sock = tcp_v4_syn_recv_sock,
2093 .remember_stamp = tcp_v4_remember_stamp,
2094 .net_header_len = sizeof(struct iphdr),
2095 .setsockopt = ip_setsockopt,
2096 .getsockopt = ip_getsockopt,
2097 .addr2sockaddr = v4_addr2sockaddr,
2098 .sockaddr_len = sizeof(struct sockaddr_in),
2101 /* NOTE: A lot of things set to zero explicitly by call to
2102 * sk_alloc() so need not be done here.
2104 static int tcp_v4_init_sock(struct sock *sk)
2106 struct tcp_opt *tp = tcp_sk(sk);
2108 skb_queue_head_init(&tp->out_of_order_queue);
2109 tcp_init_xmit_timers(sk);
2110 tcp_prequeue_init(tp);
2112 tp->rto = TCP_TIMEOUT_INIT;
2113 tp->mdev = TCP_TIMEOUT_INIT;
2115 /* So many TCP implementations out there (incorrectly) count the
2116 * initial SYN frame in their delayed-ACK and congestion control
2117 * algorithms that we must have the following bandaid to talk
2118 * efficiently to them. -DaveM
2122 /* See draft-stevens-tcpca-spec-01 for discussion of the
2123 * initialization of these values.
2125 tp->snd_ssthresh = 0x7fffffff; /* Infinity */
2126 tp->snd_cwnd_clamp = ~0;
2127 tp->mss_cache_std = tp->mss_cache = 536;
2129 tp->reordering = sysctl_tcp_reordering;
2131 sk->sk_state = TCP_CLOSE;
2133 sk->sk_write_space = sk_stream_write_space;
2134 sk->sk_use_write_queue = 1;
2136 tp->af_specific = &ipv4_specific;
2138 sk->sk_sndbuf = sysctl_tcp_wmem[1];
2139 sk->sk_rcvbuf = sysctl_tcp_rmem[1];
2141 atomic_inc(&tcp_sockets_allocated);
2146 int tcp_v4_destroy_sock(struct sock *sk)
2148 struct tcp_opt *tp = tcp_sk(sk);
2150 tcp_clear_xmit_timers(sk);
2152 /* Cleanup up the write buffer. */
2153 sk_stream_writequeue_purge(sk);
2155 /* Cleans up our, hopefully empty, out_of_order_queue. */
2156 __skb_queue_purge(&tp->out_of_order_queue);
2158 /* Clean prequeue, it must be empty really */
2159 __skb_queue_purge(&tp->ucopy.prequeue);
2161 /* Clean up a referenced TCP bind bucket. */
2166 * If sendmsg cached page exists, toss it.
2168 if (sk->sk_sndmsg_page) {
2169 __free_page(sk->sk_sndmsg_page);
2170 sk->sk_sndmsg_page = NULL;
2173 atomic_dec(&tcp_sockets_allocated);
2178 EXPORT_SYMBOL(tcp_v4_destroy_sock);
2180 #ifdef CONFIG_PROC_FS
2181 /* Proc filesystem TCP sock list dumping. */
2183 static inline struct tcp_tw_bucket *tw_head(struct hlist_head *head)
2185 return hlist_empty(head) ? NULL :
2186 list_entry(head->first, struct tcp_tw_bucket, tw_node);
2189 static inline struct tcp_tw_bucket *tw_next(struct tcp_tw_bucket *tw)
2191 return tw->tw_node.next ?
2192 hlist_entry(tw->tw_node.next, typeof(*tw), tw_node) : NULL;
2195 static void *listening_get_next(struct seq_file *seq, void *cur)
2198 struct hlist_node *node;
2199 struct sock *sk = cur;
2200 struct tcp_iter_state* st = seq->private;
2204 sk = sk_head(&tcp_listening_hash[0]);
2210 if (st->state == TCP_SEQ_STATE_OPENREQ) {
2211 struct open_request *req = cur;
2213 tp = tcp_sk(st->syn_wait_sk);
2217 vxdprintk(VXD_CBIT(net, 6),
2218 "sk,req: %p [#%d] (from %d)", req->sk,
2219 (req->sk)?req->sk->sk_xid:0, current->xid);
2221 !vx_check(req->sk->sk_xid, VX_IDENT|VX_WATCH))
2223 if (req->class->family == st->family) {
2229 if (++st->sbucket >= TCP_SYNQ_HSIZE)
2232 req = tp->listen_opt->syn_table[st->sbucket];
2234 sk = sk_next(st->syn_wait_sk);
2235 st->state = TCP_SEQ_STATE_LISTENING;
2236 read_unlock_bh(&tp->syn_wait_lock);
2239 read_lock_bh(&tp->syn_wait_lock);
2240 if (tp->listen_opt && tp->listen_opt->qlen)
2242 read_unlock_bh(&tp->syn_wait_lock);
2246 sk_for_each_from(sk, node) {
2247 vxdprintk(VXD_CBIT(net, 6), "sk: %p [#%d] (from %d)",
2248 sk, sk->sk_xid, current->xid);
2249 if (!vx_check(sk->sk_xid, VX_IDENT|VX_WATCH))
2251 if (sk->sk_family == st->family) {
2256 read_lock_bh(&tp->syn_wait_lock);
2257 if (tp->listen_opt && tp->listen_opt->qlen) {
2259 st->uid = sock_i_uid(sk);
2260 st->syn_wait_sk = sk;
2261 st->state = TCP_SEQ_STATE_OPENREQ;
2265 read_unlock_bh(&tp->syn_wait_lock);
2267 if (++st->bucket < TCP_LHTABLE_SIZE) {
2268 sk = sk_head(&tcp_listening_hash[st->bucket]);
2276 static void *listening_get_idx(struct seq_file *seq, loff_t *pos)
2278 void *rc = listening_get_next(seq, NULL);
2280 while (rc && *pos) {
2281 rc = listening_get_next(seq, rc);
2287 static void *established_get_first(struct seq_file *seq)
2289 struct tcp_iter_state* st = seq->private;
2292 for (st->bucket = 0; st->bucket < tcp_ehash_size; ++st->bucket) {
2294 struct hlist_node *node;
2295 struct tcp_tw_bucket *tw;
2297 read_lock(&tcp_ehash[st->bucket].lock);
2298 sk_for_each(sk, node, &tcp_ehash[st->bucket].chain) {
2299 vxdprintk(VXD_CBIT(net, 6),
2300 "sk,egf: %p [#%d] (from %d)",
2301 sk, sk->sk_xid, current->xid);
2302 if (!vx_check(sk->sk_xid, VX_IDENT|VX_WATCH))
2304 if (sk->sk_family != st->family)
2309 st->state = TCP_SEQ_STATE_TIME_WAIT;
2310 tw_for_each(tw, node,
2311 &tcp_ehash[st->bucket + tcp_ehash_size].chain) {
2312 vxdprintk(VXD_CBIT(net, 6),
2313 "tw: %p [#%d] (from %d)",
2314 tw, tw->tw_xid, current->xid);
2315 if (!vx_check(tw->tw_xid, VX_IDENT|VX_WATCH))
2317 if (tw->tw_family != st->family)
2322 read_unlock(&tcp_ehash[st->bucket].lock);
2323 st->state = TCP_SEQ_STATE_ESTABLISHED;
2329 static void *established_get_next(struct seq_file *seq, void *cur)
2331 struct sock *sk = cur;
2332 struct tcp_tw_bucket *tw;
2333 struct hlist_node *node;
2334 struct tcp_iter_state* st = seq->private;
2338 if (st->state == TCP_SEQ_STATE_TIME_WAIT) {
2342 while (tw && (tw->tw_family != st->family ||
2343 !vx_check(tw->tw_xid, VX_IDENT|VX_WATCH))) {
2350 read_unlock(&tcp_ehash[st->bucket].lock);
2351 st->state = TCP_SEQ_STATE_ESTABLISHED;
2352 if (++st->bucket < tcp_ehash_size) {
2353 read_lock(&tcp_ehash[st->bucket].lock);
2354 sk = sk_head(&tcp_ehash[st->bucket].chain);
2362 sk_for_each_from(sk, node) {
2363 vxdprintk(VXD_CBIT(net, 6),
2364 "sk,egn: %p [#%d] (from %d)",
2365 sk, sk->sk_xid, current->xid);
2366 if (!vx_check(sk->sk_xid, VX_IDENT|VX_WATCH))
2368 if (sk->sk_family == st->family)
2372 st->state = TCP_SEQ_STATE_TIME_WAIT;
2373 tw = tw_head(&tcp_ehash[st->bucket + tcp_ehash_size].chain);
2381 static void *established_get_idx(struct seq_file *seq, loff_t pos)
2383 void *rc = established_get_first(seq);
2386 rc = established_get_next(seq, rc);
2392 static void *tcp_get_idx(struct seq_file *seq, loff_t pos)
2395 struct tcp_iter_state* st = seq->private;
2398 st->state = TCP_SEQ_STATE_LISTENING;
2399 rc = listening_get_idx(seq, &pos);
2402 tcp_listen_unlock();
2404 st->state = TCP_SEQ_STATE_ESTABLISHED;
2405 rc = established_get_idx(seq, pos);
2411 static void *tcp_seq_start(struct seq_file *seq, loff_t *pos)
2413 struct tcp_iter_state* st = seq->private;
2414 st->state = TCP_SEQ_STATE_LISTENING;
2416 return *pos ? tcp_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
2419 static void *tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2422 struct tcp_iter_state* st;
2424 if (v == SEQ_START_TOKEN) {
2425 rc = tcp_get_idx(seq, 0);
2430 switch (st->state) {
2431 case TCP_SEQ_STATE_OPENREQ:
2432 case TCP_SEQ_STATE_LISTENING:
2433 rc = listening_get_next(seq, v);
2435 tcp_listen_unlock();
2437 st->state = TCP_SEQ_STATE_ESTABLISHED;
2438 rc = established_get_first(seq);
2441 case TCP_SEQ_STATE_ESTABLISHED:
2442 case TCP_SEQ_STATE_TIME_WAIT:
2443 rc = established_get_next(seq, v);
2451 static void tcp_seq_stop(struct seq_file *seq, void *v)
2453 struct tcp_iter_state* st = seq->private;
2455 switch (st->state) {
2456 case TCP_SEQ_STATE_OPENREQ:
2458 struct tcp_opt *tp = tcp_sk(st->syn_wait_sk);
2459 read_unlock_bh(&tp->syn_wait_lock);
2461 case TCP_SEQ_STATE_LISTENING:
2462 if (v != SEQ_START_TOKEN)
2463 tcp_listen_unlock();
2465 case TCP_SEQ_STATE_TIME_WAIT:
2466 case TCP_SEQ_STATE_ESTABLISHED:
2468 read_unlock(&tcp_ehash[st->bucket].lock);
2474 static int tcp_seq_open(struct inode *inode, struct file *file)
2476 struct tcp_seq_afinfo *afinfo = PDE(inode)->data;
2477 struct seq_file *seq;
2478 struct tcp_iter_state *s;
2481 if (unlikely(afinfo == NULL))
2484 s = kmalloc(sizeof(*s), GFP_KERNEL);
2487 memset(s, 0, sizeof(*s));
2488 s->family = afinfo->family;
2489 s->seq_ops.start = tcp_seq_start;
2490 s->seq_ops.next = tcp_seq_next;
2491 s->seq_ops.show = afinfo->seq_show;
2492 s->seq_ops.stop = tcp_seq_stop;
2494 rc = seq_open(file, &s->seq_ops);
2497 seq = file->private_data;
2506 int tcp_proc_register(struct tcp_seq_afinfo *afinfo)
2509 struct proc_dir_entry *p;
2513 afinfo->seq_fops->owner = afinfo->owner;
2514 afinfo->seq_fops->open = tcp_seq_open;
2515 afinfo->seq_fops->read = seq_read;
2516 afinfo->seq_fops->llseek = seq_lseek;
2517 afinfo->seq_fops->release = seq_release_private;
2519 p = proc_net_fops_create(afinfo->name, S_IRUGO, afinfo->seq_fops);
2527 void tcp_proc_unregister(struct tcp_seq_afinfo *afinfo)
2531 proc_net_remove(afinfo->name);
2532 memset(afinfo->seq_fops, 0, sizeof(*afinfo->seq_fops));
2535 static void get_openreq4(struct sock *sk, struct open_request *req,
2536 char *tmpbuf, int i, int uid)
2538 int ttd = req->expires - jiffies;
2540 sprintf(tmpbuf, "%4d: %08X:%04X %08X:%04X"
2541 " %02X %08X:%08X %02X:%08lX %08X %5d %8d %u %d %p",
2543 req->af.v4_req.loc_addr,
2544 ntohs(inet_sk(sk)->sport),
2545 req->af.v4_req.rmt_addr,
2546 ntohs(req->rmt_port),
2548 0, 0, /* could print option size, but that is af dependent. */
2549 1, /* timers active (only the expire timer) */
2550 jiffies_to_clock_t(ttd),
2553 0, /* non standard timer */
2554 0, /* open_requests have no inode */
2555 atomic_read(&sk->sk_refcnt),
2559 static void get_tcp4_sock(struct sock *sp, char *tmpbuf, int i)
2562 unsigned long timer_expires;
2563 struct tcp_opt *tp = tcp_sk(sp);
2564 struct inet_opt *inet = inet_sk(sp);
2565 unsigned int dest = inet->daddr;
2566 unsigned int src = inet->rcv_saddr;
2567 __u16 destp = ntohs(inet->dport);
2568 __u16 srcp = ntohs(inet->sport);
2570 if (tp->pending == TCP_TIME_RETRANS) {
2572 timer_expires = tp->timeout;
2573 } else if (tp->pending == TCP_TIME_PROBE0) {
2575 timer_expires = tp->timeout;
2576 } else if (timer_pending(&sp->sk_timer)) {
2578 timer_expires = sp->sk_timer.expires;
2581 timer_expires = jiffies;
2584 sprintf(tmpbuf, "%4d: %08X:%04X %08X:%04X %02X %08X:%08X %02X:%08lX "
2585 "%08X %5d %8d %lu %d %p %u %u %u %u %d",
2586 i, src, srcp, dest, destp, sp->sk_state,
2587 tp->write_seq - tp->snd_una, tp->rcv_nxt - tp->copied_seq,
2589 jiffies_to_clock_t(timer_expires - jiffies),
2594 atomic_read(&sp->sk_refcnt), sp,
2595 tp->rto, tp->ack.ato, (tp->ack.quick << 1) | tp->ack.pingpong,
2597 tp->snd_ssthresh >= 0xFFFF ? -1 : tp->snd_ssthresh);
2600 static void get_timewait4_sock(struct tcp_tw_bucket *tw, char *tmpbuf, int i)
2602 unsigned int dest, src;
2604 int ttd = tw->tw_ttd - jiffies;
2609 dest = tw->tw_daddr;
2610 src = tw->tw_rcv_saddr;
2611 destp = ntohs(tw->tw_dport);
2612 srcp = ntohs(tw->tw_sport);
2614 sprintf(tmpbuf, "%4d: %08X:%04X %08X:%04X"
2615 " %02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %p",
2616 i, src, srcp, dest, destp, tw->tw_substate, 0, 0,
2617 3, jiffies_to_clock_t(ttd), 0, 0, 0, 0,
2618 atomic_read(&tw->tw_refcnt), tw);
2623 static int tcp4_seq_show(struct seq_file *seq, void *v)
2625 struct tcp_iter_state* st;
2626 char tmpbuf[TMPSZ + 1];
2628 if (v == SEQ_START_TOKEN) {
2629 seq_printf(seq, "%-*s\n", TMPSZ - 1,
2630 " sl local_address rem_address st tx_queue "
2631 "rx_queue tr tm->when retrnsmt uid timeout "
2637 switch (st->state) {
2638 case TCP_SEQ_STATE_LISTENING:
2639 case TCP_SEQ_STATE_ESTABLISHED:
2640 get_tcp4_sock(v, tmpbuf, st->num);
2642 case TCP_SEQ_STATE_OPENREQ:
2643 get_openreq4(st->syn_wait_sk, v, tmpbuf, st->num, st->uid);
2645 case TCP_SEQ_STATE_TIME_WAIT:
2646 get_timewait4_sock(v, tmpbuf, st->num);
2649 seq_printf(seq, "%-*s\n", TMPSZ - 1, tmpbuf);
2654 static struct file_operations tcp4_seq_fops;
2655 static struct tcp_seq_afinfo tcp4_seq_afinfo = {
2656 .owner = THIS_MODULE,
2659 .seq_show = tcp4_seq_show,
2660 .seq_fops = &tcp4_seq_fops,
2663 int __init tcp4_proc_init(void)
2665 return tcp_proc_register(&tcp4_seq_afinfo);
2668 void tcp4_proc_exit(void)
2670 tcp_proc_unregister(&tcp4_seq_afinfo);
2672 #endif /* CONFIG_PROC_FS */
2674 struct proto tcp_prot = {
2677 .connect = tcp_v4_connect,
2678 .disconnect = tcp_disconnect,
2679 .accept = tcp_accept,
2681 .init = tcp_v4_init_sock,
2682 .destroy = tcp_v4_destroy_sock,
2683 .shutdown = tcp_shutdown,
2684 .setsockopt = tcp_setsockopt,
2685 .getsockopt = tcp_getsockopt,
2686 .sendmsg = tcp_sendmsg,
2687 .recvmsg = tcp_recvmsg,
2688 .backlog_rcv = tcp_v4_do_rcv,
2689 .hash = tcp_v4_hash,
2690 .unhash = tcp_unhash,
2691 .get_port = tcp_v4_get_port,
2692 .enter_memory_pressure = tcp_enter_memory_pressure,
2693 .sockets_allocated = &tcp_sockets_allocated,
2694 .memory_allocated = &tcp_memory_allocated,
2695 .memory_pressure = &tcp_memory_pressure,
2696 .sysctl_mem = sysctl_tcp_mem,
2697 .sysctl_wmem = sysctl_tcp_wmem,
2698 .sysctl_rmem = sysctl_tcp_rmem,
2699 .max_header = MAX_TCP_HEADER,
2700 .slab_obj_size = sizeof(struct tcp_sock),
2705 void __init tcp_v4_init(struct net_proto_family *ops)
2707 int err = sock_create_kern(PF_INET, SOCK_RAW, IPPROTO_TCP, &tcp_socket);
2709 panic("Failed to create the TCP control socket.\n");
2710 tcp_socket->sk->sk_allocation = GFP_ATOMIC;
2711 inet_sk(tcp_socket->sk)->uc_ttl = -1;
2713 /* Unhash it so that IP input processing does not even
2714 * see it, we do not wish this socket to see incoming
2717 tcp_socket->sk->sk_prot->unhash(tcp_socket->sk);
2720 EXPORT_SYMBOL(ipv4_specific);
2721 EXPORT_SYMBOL(tcp_bind_hash);
2722 EXPORT_SYMBOL(tcp_bucket_create);
2723 EXPORT_SYMBOL(tcp_hashinfo);
2724 EXPORT_SYMBOL(tcp_inherit_port);
2725 EXPORT_SYMBOL(tcp_listen_wlock);
2726 EXPORT_SYMBOL(tcp_port_rover);
2727 EXPORT_SYMBOL(tcp_prot);
2728 EXPORT_SYMBOL(tcp_put_port);
2729 EXPORT_SYMBOL(tcp_unhash);
2730 EXPORT_SYMBOL(tcp_v4_conn_request);
2731 EXPORT_SYMBOL(tcp_v4_connect);
2732 EXPORT_SYMBOL(tcp_v4_do_rcv);
2733 EXPORT_SYMBOL_GPL(tcp_v4_lookup_listener);
2734 EXPORT_SYMBOL(tcp_v4_rebuild_header);
2735 EXPORT_SYMBOL(tcp_v4_remember_stamp);
2736 EXPORT_SYMBOL(tcp_v4_send_check);
2737 EXPORT_SYMBOL(tcp_v4_syn_recv_sock);
2739 #ifdef CONFIG_PROC_FS
2740 EXPORT_SYMBOL(tcp_proc_register);
2741 EXPORT_SYMBOL(tcp_proc_unregister);
2743 #ifdef CONFIG_SYSCTL
2744 EXPORT_SYMBOL(sysctl_local_port_range);
2745 EXPORT_SYMBOL(sysctl_max_syn_backlog);
2746 EXPORT_SYMBOL(sysctl_tcp_low_latency);