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 * request_sock handling and moved
40 * most of it into the af independent code.
41 * Added tail drop and some other bugfixes.
42 * Added new listen semantics.
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>
67 #include <net/inet_hashtables.h>
69 #include <net/transp_v6.h>
71 #include <net/inet_common.h>
72 #include <net/timewait_sock.h>
75 #include <linux/inet.h>
76 #include <linux/ipv6.h>
77 #include <linux/stddef.h>
78 #include <linux/proc_fs.h>
79 #include <linux/seq_file.h>
81 int sysctl_tcp_tw_reuse;
82 int sysctl_tcp_low_latency;
84 /* Check TCP sequence numbers in ICMP packets. */
85 #define ICMP_MIN_LENGTH 8
87 /* Socket used for sending RSTs */
88 static struct socket *tcp_socket;
90 void tcp_v4_send_check(struct sock *sk, int len, struct sk_buff *skb);
92 struct inet_hashinfo __cacheline_aligned tcp_hashinfo = {
93 .lhash_lock = RW_LOCK_UNLOCKED,
94 .lhash_users = ATOMIC_INIT(0),
95 .lhash_wait = __WAIT_QUEUE_HEAD_INITIALIZER(tcp_hashinfo.lhash_wait),
98 static int tcp_v4_get_port(struct sock *sk, unsigned short snum)
100 return inet_csk_get_port(&tcp_hashinfo, sk, snum,
101 inet_csk_bind_conflict);
104 static void tcp_v4_hash(struct sock *sk)
106 inet_hash(&tcp_hashinfo, sk);
109 void tcp_unhash(struct sock *sk)
111 inet_unhash(&tcp_hashinfo, sk);
114 static inline __u32 tcp_v4_init_sequence(struct sock *sk, struct sk_buff *skb)
116 return secure_tcp_sequence_number(skb->nh.iph->daddr,
122 int tcp_twsk_unique(struct sock *sk, struct sock *sktw, void *twp)
124 const struct tcp_timewait_sock *tcptw = tcp_twsk(sktw);
125 struct tcp_sock *tp = tcp_sk(sk);
127 /* With PAWS, it is safe from the viewpoint
128 of data integrity. Even without PAWS it is safe provided sequence
129 spaces do not overlap i.e. at data rates <= 80Mbit/sec.
131 Actually, the idea is close to VJ's one, only timestamp cache is
132 held not per host, but per port pair and TW bucket is used as state
135 If TW bucket has been already destroyed we fall back to VJ's scheme
136 and use initial timestamp retrieved from peer table.
138 if (tcptw->tw_ts_recent_stamp &&
139 (twp == NULL || (sysctl_tcp_tw_reuse &&
140 xtime.tv_sec - tcptw->tw_ts_recent_stamp > 1))) {
141 tp->write_seq = tcptw->tw_snd_nxt + 65535 + 2;
142 if (tp->write_seq == 0)
144 tp->rx_opt.ts_recent = tcptw->tw_ts_recent;
145 tp->rx_opt.ts_recent_stamp = tcptw->tw_ts_recent_stamp;
153 EXPORT_SYMBOL_GPL(tcp_twsk_unique);
155 /* This will initiate an outgoing connection. */
156 int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
158 struct inet_sock *inet = inet_sk(sk);
159 struct tcp_sock *tp = tcp_sk(sk);
160 struct sockaddr_in *usin = (struct sockaddr_in *)uaddr;
166 if (addr_len < sizeof(struct sockaddr_in))
169 if (usin->sin_family != AF_INET)
170 return -EAFNOSUPPORT;
172 nexthop = daddr = usin->sin_addr.s_addr;
173 if (inet->opt && inet->opt->srr) {
176 nexthop = inet->opt->faddr;
179 tmp = ip_route_connect(&rt, nexthop, inet->saddr,
180 RT_CONN_FLAGS(sk), sk->sk_bound_dev_if,
182 inet->sport, usin->sin_port, sk);
186 if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) {
191 if (!inet->opt || !inet->opt->srr)
195 inet->saddr = rt->rt_src;
196 inet->rcv_saddr = inet->saddr;
198 if (tp->rx_opt.ts_recent_stamp && inet->daddr != daddr) {
199 /* Reset inherited state */
200 tp->rx_opt.ts_recent = 0;
201 tp->rx_opt.ts_recent_stamp = 0;
205 if (tcp_death_row.sysctl_tw_recycle &&
206 !tp->rx_opt.ts_recent_stamp && rt->rt_dst == daddr) {
207 struct inet_peer *peer = rt_get_peer(rt);
209 /* VJ's idea. We save last timestamp seen from
210 * the destination in peer table, when entering state TIME-WAIT
211 * and initialize rx_opt.ts_recent from it, when trying new connection.
214 if (peer && peer->tcp_ts_stamp + TCP_PAWS_MSL >= xtime.tv_sec) {
215 tp->rx_opt.ts_recent_stamp = peer->tcp_ts_stamp;
216 tp->rx_opt.ts_recent = peer->tcp_ts;
220 inet->dport = usin->sin_port;
223 inet_csk(sk)->icsk_ext_hdr_len = 0;
225 inet_csk(sk)->icsk_ext_hdr_len = inet->opt->optlen;
227 tp->rx_opt.mss_clamp = 536;
229 /* Socket identity is still unknown (sport may be zero).
230 * However we set state to SYN-SENT and not releasing socket
231 * lock select source port, enter ourselves into the hash tables and
232 * complete initialization after this.
234 tcp_set_state(sk, TCP_SYN_SENT);
235 err = inet_hash_connect(&tcp_death_row, sk);
239 err = ip_route_newports(&rt, IPPROTO_TCP, inet->sport, inet->dport, sk);
243 /* OK, now commit destination to socket. */
244 sk_setup_caps(sk, &rt->u.dst);
247 tp->write_seq = secure_tcp_sequence_number(inet->saddr,
252 inet->id = tp->write_seq ^ jiffies;
254 err = tcp_connect(sk);
262 /* This unhashes the socket and releases the local port, if necessary. */
263 tcp_set_state(sk, TCP_CLOSE);
265 sk->sk_route_caps = 0;
271 * This routine does path mtu discovery as defined in RFC1191.
273 static void do_pmtu_discovery(struct sock *sk, struct iphdr *iph, u32 mtu)
275 struct dst_entry *dst;
276 struct inet_sock *inet = inet_sk(sk);
278 /* We are not interested in TCP_LISTEN and open_requests (SYN-ACKs
279 * send out by Linux are always <576bytes so they should go through
282 if (sk->sk_state == TCP_LISTEN)
285 /* We don't check in the destentry if pmtu discovery is forbidden
286 * on this route. We just assume that no packet_to_big packets
287 * are send back when pmtu discovery is not active.
288 * There is a small race when the user changes this flag in the
289 * route, but I think that's acceptable.
291 if ((dst = __sk_dst_check(sk, 0)) == NULL)
294 dst->ops->update_pmtu(dst, mtu);
296 /* Something is about to be wrong... Remember soft error
297 * for the case, if this connection will not able to recover.
299 if (mtu < dst_mtu(dst) && ip_dont_fragment(sk, dst))
300 sk->sk_err_soft = EMSGSIZE;
304 if (inet->pmtudisc != IP_PMTUDISC_DONT &&
305 inet_csk(sk)->icsk_pmtu_cookie > mtu) {
306 tcp_sync_mss(sk, mtu);
308 /* Resend the TCP packet because it's
309 * clear that the old packet has been
310 * dropped. This is the new "fast" path mtu
313 tcp_simple_retransmit(sk);
314 } /* else let the usual retransmit timer handle it */
318 * This routine is called by the ICMP module when it gets some
319 * sort of error condition. If err < 0 then the socket should
320 * be closed and the error returned to the user. If err > 0
321 * it's just the icmp type << 8 | icmp code. After adjustment
322 * header points to the first 8 bytes of the tcp header. We need
323 * to find the appropriate port.
325 * The locking strategy used here is very "optimistic". When
326 * someone else accesses the socket the ICMP is just dropped
327 * and for some paths there is no check at all.
328 * A more general error queue to queue errors for later handling
329 * is probably better.
333 void tcp_v4_err(struct sk_buff *skb, u32 info)
335 struct iphdr *iph = (struct iphdr *)skb->data;
336 struct tcphdr *th = (struct tcphdr *)(skb->data + (iph->ihl << 2));
338 struct inet_sock *inet;
339 int type = skb->h.icmph->type;
340 int code = skb->h.icmph->code;
345 if (skb->len < (iph->ihl << 2) + 8) {
346 ICMP_INC_STATS_BH(ICMP_MIB_INERRORS);
350 sk = inet_lookup(&tcp_hashinfo, iph->daddr, th->dest, iph->saddr,
351 th->source, inet_iif(skb));
353 ICMP_INC_STATS_BH(ICMP_MIB_INERRORS);
356 if (sk->sk_state == TCP_TIME_WAIT) {
357 inet_twsk_put((struct inet_timewait_sock *)sk);
362 /* If too many ICMPs get dropped on busy
363 * servers this needs to be solved differently.
365 if (sock_owned_by_user(sk))
366 NET_INC_STATS_BH(LINUX_MIB_LOCKDROPPEDICMPS);
368 if (sk->sk_state == TCP_CLOSE)
372 seq = ntohl(th->seq);
373 if (sk->sk_state != TCP_LISTEN &&
374 !between(seq, tp->snd_una, tp->snd_nxt)) {
375 NET_INC_STATS(LINUX_MIB_OUTOFWINDOWICMPS);
380 case ICMP_SOURCE_QUENCH:
381 /* Just silently ignore these. */
383 case ICMP_PARAMETERPROB:
386 case ICMP_DEST_UNREACH:
387 if (code > NR_ICMP_UNREACH)
390 if (code == ICMP_FRAG_NEEDED) { /* PMTU discovery (RFC1191) */
391 if (!sock_owned_by_user(sk))
392 do_pmtu_discovery(sk, iph, info);
396 err = icmp_err_convert[code].errno;
398 case ICMP_TIME_EXCEEDED:
405 switch (sk->sk_state) {
406 struct request_sock *req, **prev;
408 if (sock_owned_by_user(sk))
411 req = inet_csk_search_req(sk, &prev, th->dest,
412 iph->daddr, iph->saddr);
416 /* ICMPs are not backlogged, hence we cannot get
417 an established socket here.
421 if (seq != tcp_rsk(req)->snt_isn) {
422 NET_INC_STATS_BH(LINUX_MIB_OUTOFWINDOWICMPS);
427 * Still in SYN_RECV, just remove it silently.
428 * There is no good way to pass the error to the newly
429 * created socket, and POSIX does not want network
430 * errors returned from accept().
432 inet_csk_reqsk_queue_drop(sk, req, prev);
436 case TCP_SYN_RECV: /* Cannot happen.
437 It can f.e. if SYNs crossed.
439 if (!sock_owned_by_user(sk)) {
440 TCP_INC_STATS_BH(TCP_MIB_ATTEMPTFAILS);
443 sk->sk_error_report(sk);
447 sk->sk_err_soft = err;
452 /* If we've already connected we will keep trying
453 * until we time out, or the user gives up.
455 * rfc1122 4.2.3.9 allows to consider as hard errors
456 * only PROTO_UNREACH and PORT_UNREACH (well, FRAG_FAILED too,
457 * but it is obsoleted by pmtu discovery).
459 * Note, that in modern internet, where routing is unreliable
460 * and in each dark corner broken firewalls sit, sending random
461 * errors ordered by their masters even this two messages finally lose
462 * their original sense (even Linux sends invalid PORT_UNREACHs)
464 * Now we are in compliance with RFCs.
469 if (!sock_owned_by_user(sk) && inet->recverr) {
471 sk->sk_error_report(sk);
472 } else { /* Only an error on timeout */
473 sk->sk_err_soft = err;
481 /* This routine computes an IPv4 TCP checksum. */
482 void tcp_v4_send_check(struct sock *sk, int len, struct sk_buff *skb)
484 struct inet_sock *inet = inet_sk(sk);
485 struct tcphdr *th = skb->h.th;
487 if (skb->ip_summed == CHECKSUM_HW) {
488 th->check = ~tcp_v4_check(th, len, inet->saddr, inet->daddr, 0);
489 skb->csum = offsetof(struct tcphdr, check);
491 th->check = tcp_v4_check(th, len, inet->saddr, inet->daddr,
492 csum_partial((char *)th,
499 * This routine will send an RST to the other tcp.
501 * Someone asks: why I NEVER use socket parameters (TOS, TTL etc.)
503 * Answer: if a packet caused RST, it is not for a socket
504 * existing in our system, if it is matched to a socket,
505 * it is just duplicate segment or bug in other side's TCP.
506 * So that we build reply only basing on parameters
507 * arrived with segment.
508 * Exception: precedence violation. We do not implement it in any case.
511 static void tcp_v4_send_reset(struct sk_buff *skb)
513 struct tcphdr *th = skb->h.th;
515 struct ip_reply_arg arg;
517 /* Never send a reset in response to a reset. */
521 if (((struct rtable *)skb->dst)->rt_type != RTN_LOCAL)
524 /* Swap the send and the receive. */
525 memset(&rth, 0, sizeof(struct tcphdr));
526 rth.dest = th->source;
527 rth.source = th->dest;
528 rth.doff = sizeof(struct tcphdr) / 4;
532 rth.seq = th->ack_seq;
535 rth.ack_seq = htonl(ntohl(th->seq) + th->syn + th->fin +
536 skb->len - (th->doff << 2));
539 memset(&arg, 0, sizeof arg);
540 arg.iov[0].iov_base = (unsigned char *)&rth;
541 arg.iov[0].iov_len = sizeof rth;
542 arg.csum = csum_tcpudp_nofold(skb->nh.iph->daddr,
543 skb->nh.iph->saddr, /*XXX*/
544 sizeof(struct tcphdr), IPPROTO_TCP, 0);
545 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
547 ip_send_reply(tcp_socket->sk, skb, &arg, sizeof rth);
549 TCP_INC_STATS_BH(TCP_MIB_OUTSEGS);
550 TCP_INC_STATS_BH(TCP_MIB_OUTRSTS);
553 /* The code following below sending ACKs in SYN-RECV and TIME-WAIT states
554 outside socket context is ugly, certainly. What can I do?
557 static void tcp_v4_send_ack(struct sk_buff *skb, u32 seq, u32 ack,
560 struct tcphdr *th = skb->h.th;
565 struct ip_reply_arg arg;
567 memset(&rep.th, 0, sizeof(struct tcphdr));
568 memset(&arg, 0, sizeof arg);
570 arg.iov[0].iov_base = (unsigned char *)&rep;
571 arg.iov[0].iov_len = sizeof(rep.th);
573 rep.tsopt[0] = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
574 (TCPOPT_TIMESTAMP << 8) |
576 rep.tsopt[1] = htonl(tcp_time_stamp);
577 rep.tsopt[2] = htonl(ts);
578 arg.iov[0].iov_len = sizeof(rep);
581 /* Swap the send and the receive. */
582 rep.th.dest = th->source;
583 rep.th.source = th->dest;
584 rep.th.doff = arg.iov[0].iov_len / 4;
585 rep.th.seq = htonl(seq);
586 rep.th.ack_seq = htonl(ack);
588 rep.th.window = htons(win);
590 arg.csum = csum_tcpudp_nofold(skb->nh.iph->daddr,
591 skb->nh.iph->saddr, /*XXX*/
592 arg.iov[0].iov_len, IPPROTO_TCP, 0);
593 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
595 ip_send_reply(tcp_socket->sk, skb, &arg, arg.iov[0].iov_len);
597 TCP_INC_STATS_BH(TCP_MIB_OUTSEGS);
600 static void tcp_v4_timewait_ack(struct sock *sk, struct sk_buff *skb)
602 struct inet_timewait_sock *tw = inet_twsk(sk);
603 const struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
605 tcp_v4_send_ack(skb, tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
606 tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale, tcptw->tw_ts_recent);
611 static void tcp_v4_reqsk_send_ack(struct sk_buff *skb, struct request_sock *req)
613 tcp_v4_send_ack(skb, tcp_rsk(req)->snt_isn + 1, tcp_rsk(req)->rcv_isn + 1, req->rcv_wnd,
618 * Send a SYN-ACK after having received an ACK.
619 * This still operates on a request_sock only, not on a big
622 static int tcp_v4_send_synack(struct sock *sk, struct request_sock *req,
623 struct dst_entry *dst)
625 const struct inet_request_sock *ireq = inet_rsk(req);
627 struct sk_buff * skb;
629 /* First, grab a route. */
630 if (!dst && (dst = inet_csk_route_req(sk, req)) == NULL)
633 skb = tcp_make_synack(sk, dst, req);
636 struct tcphdr *th = skb->h.th;
638 th->check = tcp_v4_check(th, skb->len,
641 csum_partial((char *)th, skb->len,
644 err = ip_build_and_send_pkt(skb, sk, ireq->loc_addr,
647 if (err == NET_XMIT_CN)
657 * IPv4 request_sock destructor.
659 static void tcp_v4_reqsk_destructor(struct request_sock *req)
661 kfree(inet_rsk(req)->opt);
664 #ifdef CONFIG_SYN_COOKIES
665 static void syn_flood_warning(struct sk_buff *skb)
667 static unsigned long warntime;
669 if (time_after(jiffies, (warntime + HZ * 60))) {
672 "possible SYN flooding on port %d. Sending cookies.\n",
673 ntohs(skb->h.th->dest));
679 * Save and compile IPv4 options into the request_sock if needed.
681 static struct ip_options *tcp_v4_save_options(struct sock *sk,
684 struct ip_options *opt = &(IPCB(skb)->opt);
685 struct ip_options *dopt = NULL;
687 if (opt && opt->optlen) {
688 int opt_size = optlength(opt);
689 dopt = kmalloc(opt_size, GFP_ATOMIC);
691 if (ip_options_echo(dopt, skb)) {
700 struct request_sock_ops tcp_request_sock_ops = {
702 .obj_size = sizeof(struct tcp_request_sock),
703 .rtx_syn_ack = tcp_v4_send_synack,
704 .send_ack = tcp_v4_reqsk_send_ack,
705 .destructor = tcp_v4_reqsk_destructor,
706 .send_reset = tcp_v4_send_reset,
709 static struct timewait_sock_ops tcp_timewait_sock_ops = {
710 .twsk_obj_size = sizeof(struct tcp_timewait_sock),
711 .twsk_unique = tcp_twsk_unique,
714 int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
716 struct inet_request_sock *ireq;
717 struct tcp_options_received tmp_opt;
718 struct request_sock *req;
719 __u32 saddr = skb->nh.iph->saddr;
720 __u32 daddr = skb->nh.iph->daddr;
721 __u32 isn = TCP_SKB_CB(skb)->when;
722 struct dst_entry *dst = NULL;
723 #ifdef CONFIG_SYN_COOKIES
726 #define want_cookie 0 /* Argh, why doesn't gcc optimize this :( */
729 /* Never answer to SYNs send to broadcast or multicast */
730 if (((struct rtable *)skb->dst)->rt_flags &
731 (RTCF_BROADCAST | RTCF_MULTICAST))
734 /* TW buckets are converted to open requests without
735 * limitations, they conserve resources and peer is
736 * evidently real one.
738 if (inet_csk_reqsk_queue_is_full(sk) && !isn) {
739 #ifdef CONFIG_SYN_COOKIES
740 if (sysctl_tcp_syncookies) {
747 /* Accept backlog is full. If we have already queued enough
748 * of warm entries in syn queue, drop request. It is better than
749 * clogging syn queue with openreqs with exponentially increasing
752 if (sk_acceptq_is_full(sk) && inet_csk_reqsk_queue_young(sk) > 1)
755 req = reqsk_alloc(&tcp_request_sock_ops);
759 tcp_clear_options(&tmp_opt);
760 tmp_opt.mss_clamp = 536;
761 tmp_opt.user_mss = tcp_sk(sk)->rx_opt.user_mss;
763 tcp_parse_options(skb, &tmp_opt, 0);
766 tcp_clear_options(&tmp_opt);
767 tmp_opt.saw_tstamp = 0;
770 if (tmp_opt.saw_tstamp && !tmp_opt.rcv_tsval) {
771 /* Some OSes (unknown ones, but I see them on web server, which
772 * contains information interesting only for windows'
773 * users) do not send their stamp in SYN. It is easy case.
774 * We simply do not advertise TS support.
776 tmp_opt.saw_tstamp = 0;
777 tmp_opt.tstamp_ok = 0;
779 tmp_opt.tstamp_ok = tmp_opt.saw_tstamp;
781 tcp_openreq_init(req, &tmp_opt, skb);
783 ireq = inet_rsk(req);
784 ireq->loc_addr = daddr;
785 ireq->rmt_addr = saddr;
786 ireq->opt = tcp_v4_save_options(sk, skb);
788 TCP_ECN_create_request(req, skb->h.th);
791 #ifdef CONFIG_SYN_COOKIES
792 syn_flood_warning(skb);
794 isn = cookie_v4_init_sequence(sk, skb, &req->mss);
796 struct inet_peer *peer = NULL;
798 /* VJ's idea. We save last timestamp seen
799 * from the destination in peer table, when entering
800 * state TIME-WAIT, and check against it before
801 * accepting new connection request.
803 * If "isn" is not zero, this request hit alive
804 * timewait bucket, so that all the necessary checks
805 * are made in the function processing timewait state.
807 if (tmp_opt.saw_tstamp &&
808 tcp_death_row.sysctl_tw_recycle &&
809 (dst = inet_csk_route_req(sk, req)) != NULL &&
810 (peer = rt_get_peer((struct rtable *)dst)) != NULL &&
811 peer->v4daddr == saddr) {
812 if (xtime.tv_sec < peer->tcp_ts_stamp + TCP_PAWS_MSL &&
813 (s32)(peer->tcp_ts - req->ts_recent) >
815 NET_INC_STATS_BH(LINUX_MIB_PAWSPASSIVEREJECTED);
820 /* Kill the following clause, if you dislike this way. */
821 else if (!sysctl_tcp_syncookies &&
822 (sysctl_max_syn_backlog - inet_csk_reqsk_queue_len(sk) <
823 (sysctl_max_syn_backlog >> 2)) &&
824 (!peer || !peer->tcp_ts_stamp) &&
825 (!dst || !dst_metric(dst, RTAX_RTT))) {
826 /* Without syncookies last quarter of
827 * backlog is filled with destinations,
828 * proven to be alive.
829 * It means that we continue to communicate
830 * to destinations, already remembered
831 * to the moment of synflood.
833 LIMIT_NETDEBUG(KERN_DEBUG "TCP: drop open "
834 "request from %u.%u.%u.%u/%u\n",
836 ntohs(skb->h.th->source));
841 isn = tcp_v4_init_sequence(sk, skb);
843 tcp_rsk(req)->snt_isn = isn;
845 if (tcp_v4_send_synack(sk, req, dst))
851 inet_csk_reqsk_queue_hash_add(sk, req, TCP_TIMEOUT_INIT);
858 TCP_INC_STATS_BH(TCP_MIB_ATTEMPTFAILS);
864 * The three way handshake has completed - we got a valid synack -
865 * now create the new socket.
867 struct sock *tcp_v4_syn_recv_sock(struct sock *sk, struct sk_buff *skb,
868 struct request_sock *req,
869 struct dst_entry *dst)
871 struct inet_request_sock *ireq;
872 struct inet_sock *newinet;
873 struct tcp_sock *newtp;
876 if (sk_acceptq_is_full(sk))
879 if (!dst && (dst = inet_csk_route_req(sk, req)) == NULL)
882 newsk = tcp_create_openreq_child(sk, req, skb);
886 sk_setup_caps(newsk, dst);
888 newtp = tcp_sk(newsk);
889 newinet = inet_sk(newsk);
890 ireq = inet_rsk(req);
891 newinet->daddr = ireq->rmt_addr;
892 newinet->rcv_saddr = ireq->loc_addr;
893 newinet->saddr = ireq->loc_addr;
894 newinet->opt = ireq->opt;
896 newinet->mc_index = inet_iif(skb);
897 newinet->mc_ttl = skb->nh.iph->ttl;
898 inet_csk(newsk)->icsk_ext_hdr_len = 0;
900 inet_csk(newsk)->icsk_ext_hdr_len = newinet->opt->optlen;
901 newinet->id = newtp->write_seq ^ jiffies;
903 tcp_sync_mss(newsk, dst_mtu(dst));
904 newtp->advmss = dst_metric(dst, RTAX_ADVMSS);
905 tcp_initialize_rcv_mss(newsk);
907 __inet_hash(&tcp_hashinfo, newsk, 0);
908 __inet_inherit_port(&tcp_hashinfo, sk, newsk);
913 NET_INC_STATS_BH(LINUX_MIB_LISTENOVERFLOWS);
915 NET_INC_STATS_BH(LINUX_MIB_LISTENDROPS);
920 static struct sock *tcp_v4_hnd_req(struct sock *sk, struct sk_buff *skb)
922 struct tcphdr *th = skb->h.th;
923 struct iphdr *iph = skb->nh.iph;
925 struct request_sock **prev;
926 /* Find possible connection requests. */
927 struct request_sock *req = inet_csk_search_req(sk, &prev, th->source,
928 iph->saddr, iph->daddr);
930 return tcp_check_req(sk, skb, req, prev);
932 nsk = __inet_lookup_established(&tcp_hashinfo, skb->nh.iph->saddr,
933 th->source, skb->nh.iph->daddr,
934 ntohs(th->dest), inet_iif(skb));
937 if (nsk->sk_state != TCP_TIME_WAIT) {
941 inet_twsk_put((struct inet_timewait_sock *)nsk);
945 #ifdef CONFIG_SYN_COOKIES
946 if (!th->rst && !th->syn && th->ack)
947 sk = cookie_v4_check(sk, skb, &(IPCB(skb)->opt));
952 static int tcp_v4_checksum_init(struct sk_buff *skb)
954 if (skb->ip_summed == CHECKSUM_HW) {
955 if (!tcp_v4_check(skb->h.th, skb->len, skb->nh.iph->saddr,
956 skb->nh.iph->daddr, skb->csum)) {
957 skb->ip_summed = CHECKSUM_UNNECESSARY;
962 skb->csum = csum_tcpudp_nofold(skb->nh.iph->saddr, skb->nh.iph->daddr,
963 skb->len, IPPROTO_TCP, 0);
965 if (skb->len <= 76) {
966 return __skb_checksum_complete(skb);
972 /* The socket must have it's spinlock held when we get
975 * We have a potential double-lock case here, so even when
976 * doing backlog processing we use the BH locking scheme.
977 * This is because we cannot sleep with the original spinlock
980 int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
982 if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
984 if (tcp_rcv_established(sk, skb, skb->h.th, skb->len))
990 if (skb->len < (skb->h.th->doff << 2) || tcp_checksum_complete(skb))
993 if (sk->sk_state == TCP_LISTEN) {
994 struct sock *nsk = tcp_v4_hnd_req(sk, skb);
999 if (tcp_child_process(sk, nsk, skb))
1005 TCP_CHECK_TIMER(sk);
1006 if (tcp_rcv_state_process(sk, skb, skb->h.th, skb->len))
1008 TCP_CHECK_TIMER(sk);
1012 tcp_v4_send_reset(skb);
1015 /* Be careful here. If this function gets more complicated and
1016 * gcc suffers from register pressure on the x86, sk (in %ebx)
1017 * might be destroyed here. This current version compiles correctly,
1018 * but you have been warned.
1023 TCP_INC_STATS_BH(TCP_MIB_INERRS);
1031 int tcp_v4_rcv(struct sk_buff *skb)
1037 if (skb->pkt_type != PACKET_HOST)
1040 /* Count it even if it's bad */
1041 TCP_INC_STATS_BH(TCP_MIB_INSEGS);
1043 if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
1048 if (th->doff < sizeof(struct tcphdr) / 4)
1050 if (!pskb_may_pull(skb, th->doff * 4))
1053 /* An explanation is required here, I think.
1054 * Packet length and doff are validated by header prediction,
1055 * provided case of th->doff==0 is eliminated.
1056 * So, we defer the checks. */
1057 if ((skb->ip_summed != CHECKSUM_UNNECESSARY &&
1058 tcp_v4_checksum_init(skb)))
1062 TCP_SKB_CB(skb)->seq = ntohl(th->seq);
1063 TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
1064 skb->len - th->doff * 4);
1065 TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
1066 TCP_SKB_CB(skb)->when = 0;
1067 TCP_SKB_CB(skb)->flags = skb->nh.iph->tos;
1068 TCP_SKB_CB(skb)->sacked = 0;
1070 sk = __inet_lookup(&tcp_hashinfo, skb->nh.iph->saddr, th->source,
1071 skb->nh.iph->daddr, ntohs(th->dest),
1078 if (sk->sk_state == TCP_TIME_WAIT)
1081 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
1082 goto discard_and_relse;
1085 if (sk_filter(sk, skb, 0))
1086 goto discard_and_relse;
1092 if (!sock_owned_by_user(sk)) {
1093 if (!tcp_prequeue(sk, skb))
1094 ret = tcp_v4_do_rcv(sk, skb);
1096 sk_add_backlog(sk, skb);
1104 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
1107 if (skb->len < (th->doff << 2) || tcp_checksum_complete(skb)) {
1109 TCP_INC_STATS_BH(TCP_MIB_INERRS);
1111 tcp_v4_send_reset(skb);
1115 /* Discard frame. */
1124 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
1125 inet_twsk_put((struct inet_timewait_sock *) sk);
1129 if (skb->len < (th->doff << 2) || tcp_checksum_complete(skb)) {
1130 TCP_INC_STATS_BH(TCP_MIB_INERRS);
1131 inet_twsk_put((struct inet_timewait_sock *) sk);
1134 switch (tcp_timewait_state_process((struct inet_timewait_sock *)sk,
1137 struct sock *sk2 = inet_lookup_listener(&tcp_hashinfo,
1142 inet_twsk_deschedule((struct inet_timewait_sock *)sk,
1144 inet_twsk_put((struct inet_timewait_sock *)sk);
1148 /* Fall through to ACK */
1151 tcp_v4_timewait_ack(sk, skb);
1155 case TCP_TW_SUCCESS:;
1160 /* VJ's idea. Save last timestamp seen from this destination
1161 * and hold it at least for normal timewait interval to use for duplicate
1162 * segment detection in subsequent connections, before they enter synchronized
1166 int tcp_v4_remember_stamp(struct sock *sk)
1168 struct inet_sock *inet = inet_sk(sk);
1169 struct tcp_sock *tp = tcp_sk(sk);
1170 struct rtable *rt = (struct rtable *)__sk_dst_get(sk);
1171 struct inet_peer *peer = NULL;
1174 if (!rt || rt->rt_dst != inet->daddr) {
1175 peer = inet_getpeer(inet->daddr, 1);
1179 rt_bind_peer(rt, 1);
1184 if ((s32)(peer->tcp_ts - tp->rx_opt.ts_recent) <= 0 ||
1185 (peer->tcp_ts_stamp + TCP_PAWS_MSL < xtime.tv_sec &&
1186 peer->tcp_ts_stamp <= tp->rx_opt.ts_recent_stamp)) {
1187 peer->tcp_ts_stamp = tp->rx_opt.ts_recent_stamp;
1188 peer->tcp_ts = tp->rx_opt.ts_recent;
1198 int tcp_v4_tw_remember_stamp(struct inet_timewait_sock *tw)
1200 struct inet_peer *peer = inet_getpeer(tw->tw_daddr, 1);
1203 const struct tcp_timewait_sock *tcptw = tcp_twsk((struct sock *)tw);
1205 if ((s32)(peer->tcp_ts - tcptw->tw_ts_recent) <= 0 ||
1206 (peer->tcp_ts_stamp + TCP_PAWS_MSL < xtime.tv_sec &&
1207 peer->tcp_ts_stamp <= tcptw->tw_ts_recent_stamp)) {
1208 peer->tcp_ts_stamp = tcptw->tw_ts_recent_stamp;
1209 peer->tcp_ts = tcptw->tw_ts_recent;
1218 struct inet_connection_sock_af_ops ipv4_specific = {
1219 .queue_xmit = ip_queue_xmit,
1220 .send_check = tcp_v4_send_check,
1221 .rebuild_header = inet_sk_rebuild_header,
1222 .conn_request = tcp_v4_conn_request,
1223 .syn_recv_sock = tcp_v4_syn_recv_sock,
1224 .remember_stamp = tcp_v4_remember_stamp,
1225 .net_header_len = sizeof(struct iphdr),
1226 .setsockopt = ip_setsockopt,
1227 .getsockopt = ip_getsockopt,
1228 .addr2sockaddr = inet_csk_addr2sockaddr,
1229 .sockaddr_len = sizeof(struct sockaddr_in),
1232 /* NOTE: A lot of things set to zero explicitly by call to
1233 * sk_alloc() so need not be done here.
1235 static int tcp_v4_init_sock(struct sock *sk)
1237 struct inet_connection_sock *icsk = inet_csk(sk);
1238 struct tcp_sock *tp = tcp_sk(sk);
1240 skb_queue_head_init(&tp->out_of_order_queue);
1241 tcp_init_xmit_timers(sk);
1242 tcp_prequeue_init(tp);
1244 icsk->icsk_rto = TCP_TIMEOUT_INIT;
1245 tp->mdev = TCP_TIMEOUT_INIT;
1247 /* So many TCP implementations out there (incorrectly) count the
1248 * initial SYN frame in their delayed-ACK and congestion control
1249 * algorithms that we must have the following bandaid to talk
1250 * efficiently to them. -DaveM
1254 /* See draft-stevens-tcpca-spec-01 for discussion of the
1255 * initialization of these values.
1257 tp->snd_ssthresh = 0x7fffffff; /* Infinity */
1258 tp->snd_cwnd_clamp = ~0;
1259 tp->mss_cache = 536;
1261 tp->reordering = sysctl_tcp_reordering;
1262 icsk->icsk_ca_ops = &tcp_init_congestion_ops;
1264 sk->sk_state = TCP_CLOSE;
1266 sk->sk_write_space = sk_stream_write_space;
1267 sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
1269 icsk->icsk_af_ops = &ipv4_specific;
1270 icsk->icsk_sync_mss = tcp_sync_mss;
1272 sk->sk_sndbuf = sysctl_tcp_wmem[1];
1273 sk->sk_rcvbuf = sysctl_tcp_rmem[1];
1275 atomic_inc(&tcp_sockets_allocated);
1280 int tcp_v4_destroy_sock(struct sock *sk)
1282 struct tcp_sock *tp = tcp_sk(sk);
1284 tcp_clear_xmit_timers(sk);
1286 tcp_cleanup_congestion_control(sk);
1288 /* Cleanup up the write buffer. */
1289 sk_stream_writequeue_purge(sk);
1291 /* Cleans up our, hopefully empty, out_of_order_queue. */
1292 __skb_queue_purge(&tp->out_of_order_queue);
1294 /* Clean prequeue, it must be empty really */
1295 __skb_queue_purge(&tp->ucopy.prequeue);
1297 /* Clean up a referenced TCP bind bucket. */
1298 if (inet_csk(sk)->icsk_bind_hash)
1299 inet_put_port(&tcp_hashinfo, sk);
1302 * If sendmsg cached page exists, toss it.
1304 if (sk->sk_sndmsg_page) {
1305 __free_page(sk->sk_sndmsg_page);
1306 sk->sk_sndmsg_page = NULL;
1309 atomic_dec(&tcp_sockets_allocated);
1314 EXPORT_SYMBOL(tcp_v4_destroy_sock);
1316 #ifdef CONFIG_PROC_FS
1317 /* Proc filesystem TCP sock list dumping. */
1319 static inline struct inet_timewait_sock *tw_head(struct hlist_head *head)
1321 return hlist_empty(head) ? NULL :
1322 list_entry(head->first, struct inet_timewait_sock, tw_node);
1325 static inline struct inet_timewait_sock *tw_next(struct inet_timewait_sock *tw)
1327 return tw->tw_node.next ?
1328 hlist_entry(tw->tw_node.next, typeof(*tw), tw_node) : NULL;
1331 static void *listening_get_next(struct seq_file *seq, void *cur)
1333 struct inet_connection_sock *icsk;
1334 struct hlist_node *node;
1335 struct sock *sk = cur;
1336 struct tcp_iter_state* st = seq->private;
1340 sk = sk_head(&tcp_hashinfo.listening_hash[0]);
1346 if (st->state == TCP_SEQ_STATE_OPENREQ) {
1347 struct request_sock *req = cur;
1349 icsk = inet_csk(st->syn_wait_sk);
1353 if (req->rsk_ops->family == st->family) {
1359 if (++st->sbucket >= TCP_SYNQ_HSIZE)
1362 req = icsk->icsk_accept_queue.listen_opt->syn_table[st->sbucket];
1364 sk = sk_next(st->syn_wait_sk);
1365 st->state = TCP_SEQ_STATE_LISTENING;
1366 read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
1368 icsk = inet_csk(sk);
1369 read_lock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
1370 if (reqsk_queue_len(&icsk->icsk_accept_queue))
1372 read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
1376 sk_for_each_from(sk, node) {
1377 if (sk->sk_family == st->family) {
1381 icsk = inet_csk(sk);
1382 read_lock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
1383 if (reqsk_queue_len(&icsk->icsk_accept_queue)) {
1385 st->uid = sock_i_uid(sk);
1386 st->syn_wait_sk = sk;
1387 st->state = TCP_SEQ_STATE_OPENREQ;
1391 read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
1393 if (++st->bucket < INET_LHTABLE_SIZE) {
1394 sk = sk_head(&tcp_hashinfo.listening_hash[st->bucket]);
1402 static void *listening_get_idx(struct seq_file *seq, loff_t *pos)
1404 void *rc = listening_get_next(seq, NULL);
1406 while (rc && *pos) {
1407 rc = listening_get_next(seq, rc);
1413 static void *established_get_first(struct seq_file *seq)
1415 struct tcp_iter_state* st = seq->private;
1418 for (st->bucket = 0; st->bucket < tcp_hashinfo.ehash_size; ++st->bucket) {
1420 struct hlist_node *node;
1421 struct inet_timewait_sock *tw;
1423 /* We can reschedule _before_ having picked the target: */
1424 cond_resched_softirq();
1426 read_lock(&tcp_hashinfo.ehash[st->bucket].lock);
1427 sk_for_each(sk, node, &tcp_hashinfo.ehash[st->bucket].chain) {
1428 if (sk->sk_family != st->family) {
1434 st->state = TCP_SEQ_STATE_TIME_WAIT;
1435 inet_twsk_for_each(tw, node,
1436 &tcp_hashinfo.ehash[st->bucket + tcp_hashinfo.ehash_size].chain) {
1437 if (tw->tw_family != st->family) {
1443 read_unlock(&tcp_hashinfo.ehash[st->bucket].lock);
1444 st->state = TCP_SEQ_STATE_ESTABLISHED;
1450 static void *established_get_next(struct seq_file *seq, void *cur)
1452 struct sock *sk = cur;
1453 struct inet_timewait_sock *tw;
1454 struct hlist_node *node;
1455 struct tcp_iter_state* st = seq->private;
1459 if (st->state == TCP_SEQ_STATE_TIME_WAIT) {
1463 while (tw && tw->tw_family != st->family) {
1470 read_unlock(&tcp_hashinfo.ehash[st->bucket].lock);
1471 st->state = TCP_SEQ_STATE_ESTABLISHED;
1473 /* We can reschedule between buckets: */
1474 cond_resched_softirq();
1476 if (++st->bucket < tcp_hashinfo.ehash_size) {
1477 read_lock(&tcp_hashinfo.ehash[st->bucket].lock);
1478 sk = sk_head(&tcp_hashinfo.ehash[st->bucket].chain);
1486 sk_for_each_from(sk, node) {
1487 if (sk->sk_family == st->family)
1491 st->state = TCP_SEQ_STATE_TIME_WAIT;
1492 tw = tw_head(&tcp_hashinfo.ehash[st->bucket + tcp_hashinfo.ehash_size].chain);
1500 static void *established_get_idx(struct seq_file *seq, loff_t pos)
1502 void *rc = established_get_first(seq);
1505 rc = established_get_next(seq, rc);
1511 static void *tcp_get_idx(struct seq_file *seq, loff_t pos)
1514 struct tcp_iter_state* st = seq->private;
1516 inet_listen_lock(&tcp_hashinfo);
1517 st->state = TCP_SEQ_STATE_LISTENING;
1518 rc = listening_get_idx(seq, &pos);
1521 inet_listen_unlock(&tcp_hashinfo);
1523 st->state = TCP_SEQ_STATE_ESTABLISHED;
1524 rc = established_get_idx(seq, pos);
1530 static void *tcp_seq_start(struct seq_file *seq, loff_t *pos)
1532 struct tcp_iter_state* st = seq->private;
1533 st->state = TCP_SEQ_STATE_LISTENING;
1535 return *pos ? tcp_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
1538 static void *tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
1541 struct tcp_iter_state* st;
1543 if (v == SEQ_START_TOKEN) {
1544 rc = tcp_get_idx(seq, 0);
1549 switch (st->state) {
1550 case TCP_SEQ_STATE_OPENREQ:
1551 case TCP_SEQ_STATE_LISTENING:
1552 rc = listening_get_next(seq, v);
1554 inet_listen_unlock(&tcp_hashinfo);
1556 st->state = TCP_SEQ_STATE_ESTABLISHED;
1557 rc = established_get_first(seq);
1560 case TCP_SEQ_STATE_ESTABLISHED:
1561 case TCP_SEQ_STATE_TIME_WAIT:
1562 rc = established_get_next(seq, v);
1570 static void tcp_seq_stop(struct seq_file *seq, void *v)
1572 struct tcp_iter_state* st = seq->private;
1574 switch (st->state) {
1575 case TCP_SEQ_STATE_OPENREQ:
1577 struct inet_connection_sock *icsk = inet_csk(st->syn_wait_sk);
1578 read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
1580 case TCP_SEQ_STATE_LISTENING:
1581 if (v != SEQ_START_TOKEN)
1582 inet_listen_unlock(&tcp_hashinfo);
1584 case TCP_SEQ_STATE_TIME_WAIT:
1585 case TCP_SEQ_STATE_ESTABLISHED:
1587 read_unlock(&tcp_hashinfo.ehash[st->bucket].lock);
1593 static int tcp_seq_open(struct inode *inode, struct file *file)
1595 struct tcp_seq_afinfo *afinfo = PDE(inode)->data;
1596 struct seq_file *seq;
1597 struct tcp_iter_state *s;
1600 if (unlikely(afinfo == NULL))
1603 s = kmalloc(sizeof(*s), GFP_KERNEL);
1606 memset(s, 0, sizeof(*s));
1607 s->family = afinfo->family;
1608 s->seq_ops.start = tcp_seq_start;
1609 s->seq_ops.next = tcp_seq_next;
1610 s->seq_ops.show = afinfo->seq_show;
1611 s->seq_ops.stop = tcp_seq_stop;
1613 rc = seq_open(file, &s->seq_ops);
1616 seq = file->private_data;
1625 int tcp_proc_register(struct tcp_seq_afinfo *afinfo)
1628 struct proc_dir_entry *p;
1632 afinfo->seq_fops->owner = afinfo->owner;
1633 afinfo->seq_fops->open = tcp_seq_open;
1634 afinfo->seq_fops->read = seq_read;
1635 afinfo->seq_fops->llseek = seq_lseek;
1636 afinfo->seq_fops->release = seq_release_private;
1638 p = proc_net_fops_create(afinfo->name, S_IRUGO, afinfo->seq_fops);
1646 void tcp_proc_unregister(struct tcp_seq_afinfo *afinfo)
1650 proc_net_remove(afinfo->name);
1651 memset(afinfo->seq_fops, 0, sizeof(*afinfo->seq_fops));
1654 static void get_openreq4(struct sock *sk, struct request_sock *req,
1655 char *tmpbuf, int i, int uid)
1657 const struct inet_request_sock *ireq = inet_rsk(req);
1658 int ttd = req->expires - jiffies;
1660 sprintf(tmpbuf, "%4d: %08X:%04X %08X:%04X"
1661 " %02X %08X:%08X %02X:%08lX %08X %5d %8d %u %d %p",
1664 ntohs(inet_sk(sk)->sport),
1666 ntohs(ireq->rmt_port),
1668 0, 0, /* could print option size, but that is af dependent. */
1669 1, /* timers active (only the expire timer) */
1670 jiffies_to_clock_t(ttd),
1673 0, /* non standard timer */
1674 0, /* open_requests have no inode */
1675 atomic_read(&sk->sk_refcnt),
1679 static void get_tcp4_sock(struct sock *sp, char *tmpbuf, int i)
1682 unsigned long timer_expires;
1683 struct tcp_sock *tp = tcp_sk(sp);
1684 const struct inet_connection_sock *icsk = inet_csk(sp);
1685 struct inet_sock *inet = inet_sk(sp);
1686 unsigned int dest = inet->daddr;
1687 unsigned int src = inet->rcv_saddr;
1688 __u16 destp = ntohs(inet->dport);
1689 __u16 srcp = ntohs(inet->sport);
1691 if (icsk->icsk_pending == ICSK_TIME_RETRANS) {
1693 timer_expires = icsk->icsk_timeout;
1694 } else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
1696 timer_expires = icsk->icsk_timeout;
1697 } else if (timer_pending(&sp->sk_timer)) {
1699 timer_expires = sp->sk_timer.expires;
1702 timer_expires = jiffies;
1705 sprintf(tmpbuf, "%4d: %08X:%04X %08X:%04X %02X %08X:%08X %02X:%08lX "
1706 "%08X %5d %8d %lu %d %p %u %u %u %u %d",
1707 i, src, srcp, dest, destp, sp->sk_state,
1708 tp->write_seq - tp->snd_una, tp->rcv_nxt - tp->copied_seq,
1710 jiffies_to_clock_t(timer_expires - jiffies),
1711 icsk->icsk_retransmits,
1713 icsk->icsk_probes_out,
1715 atomic_read(&sp->sk_refcnt), sp,
1718 (icsk->icsk_ack.quick << 1) | icsk->icsk_ack.pingpong,
1720 tp->snd_ssthresh >= 0xFFFF ? -1 : tp->snd_ssthresh);
1723 static void get_timewait4_sock(struct inet_timewait_sock *tw, char *tmpbuf, int i)
1725 unsigned int dest, src;
1727 int ttd = tw->tw_ttd - jiffies;
1732 dest = tw->tw_daddr;
1733 src = tw->tw_rcv_saddr;
1734 destp = ntohs(tw->tw_dport);
1735 srcp = ntohs(tw->tw_sport);
1737 sprintf(tmpbuf, "%4d: %08X:%04X %08X:%04X"
1738 " %02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %p",
1739 i, src, srcp, dest, destp, tw->tw_substate, 0, 0,
1740 3, jiffies_to_clock_t(ttd), 0, 0, 0, 0,
1741 atomic_read(&tw->tw_refcnt), tw);
1746 static int tcp4_seq_show(struct seq_file *seq, void *v)
1748 struct tcp_iter_state* st;
1749 char tmpbuf[TMPSZ + 1];
1751 if (v == SEQ_START_TOKEN) {
1752 seq_printf(seq, "%-*s\n", TMPSZ - 1,
1753 " sl local_address rem_address st tx_queue "
1754 "rx_queue tr tm->when retrnsmt uid timeout "
1760 switch (st->state) {
1761 case TCP_SEQ_STATE_LISTENING:
1762 case TCP_SEQ_STATE_ESTABLISHED:
1763 get_tcp4_sock(v, tmpbuf, st->num);
1765 case TCP_SEQ_STATE_OPENREQ:
1766 get_openreq4(st->syn_wait_sk, v, tmpbuf, st->num, st->uid);
1768 case TCP_SEQ_STATE_TIME_WAIT:
1769 get_timewait4_sock(v, tmpbuf, st->num);
1772 seq_printf(seq, "%-*s\n", TMPSZ - 1, tmpbuf);
1777 static struct file_operations tcp4_seq_fops;
1778 static struct tcp_seq_afinfo tcp4_seq_afinfo = {
1779 .owner = THIS_MODULE,
1782 .seq_show = tcp4_seq_show,
1783 .seq_fops = &tcp4_seq_fops,
1786 int __init tcp4_proc_init(void)
1788 return tcp_proc_register(&tcp4_seq_afinfo);
1791 void tcp4_proc_exit(void)
1793 tcp_proc_unregister(&tcp4_seq_afinfo);
1795 #endif /* CONFIG_PROC_FS */
1797 struct proto tcp_prot = {
1799 .owner = THIS_MODULE,
1801 .connect = tcp_v4_connect,
1802 .disconnect = tcp_disconnect,
1803 .accept = inet_csk_accept,
1805 .init = tcp_v4_init_sock,
1806 .destroy = tcp_v4_destroy_sock,
1807 .shutdown = tcp_shutdown,
1808 .setsockopt = tcp_setsockopt,
1809 .getsockopt = tcp_getsockopt,
1810 .sendmsg = tcp_sendmsg,
1811 .recvmsg = tcp_recvmsg,
1812 .backlog_rcv = tcp_v4_do_rcv,
1813 .hash = tcp_v4_hash,
1814 .unhash = tcp_unhash,
1815 .get_port = tcp_v4_get_port,
1816 .enter_memory_pressure = tcp_enter_memory_pressure,
1817 .sockets_allocated = &tcp_sockets_allocated,
1818 .orphan_count = &tcp_orphan_count,
1819 .memory_allocated = &tcp_memory_allocated,
1820 .memory_pressure = &tcp_memory_pressure,
1821 .sysctl_mem = sysctl_tcp_mem,
1822 .sysctl_wmem = sysctl_tcp_wmem,
1823 .sysctl_rmem = sysctl_tcp_rmem,
1824 .max_header = MAX_TCP_HEADER,
1825 .obj_size = sizeof(struct tcp_sock),
1826 .twsk_prot = &tcp_timewait_sock_ops,
1827 .rsk_prot = &tcp_request_sock_ops,
1832 void __init tcp_v4_init(struct net_proto_family *ops)
1834 int err = sock_create_kern(PF_INET, SOCK_RAW, IPPROTO_TCP, &tcp_socket);
1836 panic("Failed to create the TCP control socket.\n");
1837 tcp_socket->sk->sk_allocation = GFP_ATOMIC;
1838 inet_sk(tcp_socket->sk)->uc_ttl = -1;
1840 /* Unhash it so that IP input processing does not even
1841 * see it, we do not wish this socket to see incoming
1844 tcp_socket->sk->sk_prot->unhash(tcp_socket->sk);
1847 EXPORT_SYMBOL(ipv4_specific);
1848 EXPORT_SYMBOL(tcp_hashinfo);
1849 EXPORT_SYMBOL(tcp_prot);
1850 EXPORT_SYMBOL(tcp_unhash);
1851 EXPORT_SYMBOL(tcp_v4_conn_request);
1852 EXPORT_SYMBOL(tcp_v4_connect);
1853 EXPORT_SYMBOL(tcp_v4_do_rcv);
1854 EXPORT_SYMBOL(tcp_v4_remember_stamp);
1855 EXPORT_SYMBOL(tcp_v4_send_check);
1856 EXPORT_SYMBOL(tcp_v4_syn_recv_sock);
1858 #ifdef CONFIG_PROC_FS
1859 EXPORT_SYMBOL(tcp_proc_register);
1860 EXPORT_SYMBOL(tcp_proc_unregister);
1862 EXPORT_SYMBOL(sysctl_local_port_range);
1863 EXPORT_SYMBOL(sysctl_tcp_low_latency);
1864 EXPORT_SYMBOL(sysctl_tcp_tw_reuse);