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 * IPv4 specific functions
13 * linux/ipv4/tcp_input.c
14 * linux/ipv4/tcp_output.c
16 * See tcp.c for author information
18 * This program is free software; you can redistribute it and/or
19 * modify it under the terms of the GNU General Public License
20 * as published by the Free Software Foundation; either version
21 * 2 of the License, or (at your option) any later version.
26 * David S. Miller : New socket lookup architecture.
27 * This code is dedicated to John Dyson.
28 * David S. Miller : Change semantics of established hash,
29 * half is devoted to TIME_WAIT sockets
30 * and the rest go in the other half.
31 * Andi Kleen : Add support for syncookies and fixed
32 * some bugs: ip options weren't passed to
33 * the TCP layer, missed a check for an
35 * Andi Kleen : Implemented fast path mtu discovery.
36 * Fixed many serious bugs in the
37 * request_sock handling and moved
38 * most of it into the af independent code.
39 * Added tail drop and some other bugfixes.
40 * Added new listen semantics.
41 * Mike McLagan : Routing by source
42 * Juan Jose Ciarlante: ip_dynaddr bits
43 * Andi Kleen: various fixes.
44 * Vitaly E. Lavrov : Transparent proxy revived after year
46 * Andi Kleen : Fix new listen.
47 * Andi Kleen : Fix accept error reporting.
48 * YOSHIFUJI Hideaki @USAGI and: Support IPV6_V6ONLY socket option, which
49 * Alexey Kuznetsov allow both IPv4 and IPv6 sockets to bind
50 * a single port at the same time.
54 #include <linux/bottom_half.h>
55 #include <linux/types.h>
56 #include <linux/fcntl.h>
57 #include <linux/module.h>
58 #include <linux/random.h>
59 #include <linux/cache.h>
60 #include <linux/jhash.h>
61 #include <linux/init.h>
62 #include <linux/times.h>
63 #include <linux/slab.h>
65 #include <net/net_namespace.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>
74 #include <net/netdma.h>
75 #include <net/secure_seq.h>
77 #include <linux/inet.h>
78 #include <linux/ipv6.h>
79 #include <linux/stddef.h>
80 #include <linux/proc_fs.h>
81 #include <linux/seq_file.h>
83 #include <linux/crypto.h>
84 #include <linux/scatterlist.h>
86 int sysctl_tcp_tw_reuse __read_mostly;
87 int sysctl_tcp_low_latency __read_mostly;
88 EXPORT_SYMBOL(sysctl_tcp_low_latency);
91 #ifdef CONFIG_TCP_MD5SIG
92 static struct tcp_md5sig_key *tcp_v4_md5_do_lookup(struct sock *sk,
94 static int tcp_v4_md5_hash_hdr(char *md5_hash, struct tcp_md5sig_key *key,
95 __be32 daddr, __be32 saddr, struct tcphdr *th);
98 struct tcp_md5sig_key *tcp_v4_md5_do_lookup(struct sock *sk, __be32 addr)
104 struct inet_hashinfo tcp_hashinfo;
105 EXPORT_SYMBOL(tcp_hashinfo);
107 static inline __u32 tcp_v4_init_sequence(struct sk_buff *skb)
109 return secure_tcp_sequence_number(ip_hdr(skb)->daddr,
112 tcp_hdr(skb)->source);
115 int tcp_twsk_unique(struct sock *sk, struct sock *sktw, void *twp)
117 const struct tcp_timewait_sock *tcptw = tcp_twsk(sktw);
118 struct tcp_sock *tp = tcp_sk(sk);
120 /* With PAWS, it is safe from the viewpoint
121 of data integrity. Even without PAWS it is safe provided sequence
122 spaces do not overlap i.e. at data rates <= 80Mbit/sec.
124 Actually, the idea is close to VJ's one, only timestamp cache is
125 held not per host, but per port pair and TW bucket is used as state
128 If TW bucket has been already destroyed we fall back to VJ's scheme
129 and use initial timestamp retrieved from peer table.
131 if (tcptw->tw_ts_recent_stamp &&
132 (twp == NULL || (sysctl_tcp_tw_reuse &&
133 get_seconds() - tcptw->tw_ts_recent_stamp > 1))) {
134 tp->write_seq = tcptw->tw_snd_nxt + 65535 + 2;
135 if (tp->write_seq == 0)
137 tp->rx_opt.ts_recent = tcptw->tw_ts_recent;
138 tp->rx_opt.ts_recent_stamp = tcptw->tw_ts_recent_stamp;
145 EXPORT_SYMBOL_GPL(tcp_twsk_unique);
147 /* This will initiate an outgoing connection. */
148 int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
150 struct sockaddr_in *usin = (struct sockaddr_in *)uaddr;
151 struct inet_sock *inet = inet_sk(sk);
152 struct tcp_sock *tp = tcp_sk(sk);
153 __be16 orig_sport, orig_dport;
154 __be32 daddr, nexthop;
158 struct ip_options_rcu *inet_opt;
160 if (addr_len < sizeof(struct sockaddr_in))
163 if (usin->sin_family != AF_INET)
164 return -EAFNOSUPPORT;
166 nexthop = daddr = usin->sin_addr.s_addr;
167 inet_opt = rcu_dereference_protected(inet->inet_opt,
168 sock_owned_by_user(sk));
169 if (inet_opt && inet_opt->opt.srr) {
172 nexthop = inet_opt->opt.faddr;
175 orig_sport = inet->inet_sport;
176 orig_dport = usin->sin_port;
177 fl4 = &inet->cork.fl.u.ip4;
178 rt = ip_route_connect(fl4, nexthop, inet->inet_saddr,
179 RT_CONN_FLAGS(sk), sk->sk_bound_dev_if,
181 orig_sport, orig_dport, sk, true);
184 if (err == -ENETUNREACH)
185 IP_INC_STATS_BH(sock_net(sk), IPSTATS_MIB_OUTNOROUTES);
189 if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) {
194 if (!inet_opt || !inet_opt->opt.srr)
197 if (!inet->inet_saddr)
198 inet->inet_saddr = fl4->saddr;
199 inet->inet_rcv_saddr = inet->inet_saddr;
201 if (tp->rx_opt.ts_recent_stamp && inet->inet_daddr != daddr) {
202 /* Reset inherited state */
203 tp->rx_opt.ts_recent = 0;
204 tp->rx_opt.ts_recent_stamp = 0;
208 if (tcp_death_row.sysctl_tw_recycle &&
209 !tp->rx_opt.ts_recent_stamp && fl4->daddr == daddr) {
210 struct inet_peer *peer = rt_get_peer(rt, fl4->daddr);
212 * VJ's idea. We save last timestamp seen from
213 * the destination in peer table, when entering state
214 * TIME-WAIT * and initialize rx_opt.ts_recent from it,
215 * when trying new connection.
218 inet_peer_refcheck(peer);
219 if ((u32)get_seconds() - peer->tcp_ts_stamp <= TCP_PAWS_MSL) {
220 tp->rx_opt.ts_recent_stamp = peer->tcp_ts_stamp;
221 tp->rx_opt.ts_recent = peer->tcp_ts;
226 inet->inet_dport = usin->sin_port;
227 inet->inet_daddr = daddr;
229 inet_csk(sk)->icsk_ext_hdr_len = 0;
231 inet_csk(sk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
233 tp->rx_opt.mss_clamp = TCP_MSS_DEFAULT;
235 /* Socket identity is still unknown (sport may be zero).
236 * However we set state to SYN-SENT and not releasing socket
237 * lock select source port, enter ourselves into the hash tables and
238 * complete initialization after this.
240 tcp_set_state(sk, TCP_SYN_SENT);
241 err = inet_hash_connect(&tcp_death_row, sk);
245 rt = ip_route_newports(fl4, rt, orig_sport, orig_dport,
246 inet->inet_sport, inet->inet_dport, sk);
252 /* OK, now commit destination to socket. */
253 sk->sk_gso_type = SKB_GSO_TCPV4;
254 sk_setup_caps(sk, &rt->dst);
257 tp->write_seq = secure_tcp_sequence_number(inet->inet_saddr,
262 inet->inet_id = tp->write_seq ^ jiffies;
264 err = tcp_connect(sk);
273 * This unhashes the socket and releases the local port,
276 tcp_set_state(sk, TCP_CLOSE);
278 sk->sk_route_caps = 0;
279 inet->inet_dport = 0;
282 EXPORT_SYMBOL(tcp_v4_connect);
285 * This routine does path mtu discovery as defined in RFC1191.
287 static void do_pmtu_discovery(struct sock *sk, const struct iphdr *iph, u32 mtu)
289 struct dst_entry *dst;
290 struct inet_sock *inet = inet_sk(sk);
292 /* We are not interested in TCP_LISTEN and open_requests (SYN-ACKs
293 * send out by Linux are always <576bytes so they should go through
296 if (sk->sk_state == TCP_LISTEN)
299 /* We don't check in the destentry if pmtu discovery is forbidden
300 * on this route. We just assume that no packet_to_big packets
301 * are send back when pmtu discovery is not active.
302 * There is a small race when the user changes this flag in the
303 * route, but I think that's acceptable.
305 if ((dst = __sk_dst_check(sk, 0)) == NULL)
308 dst->ops->update_pmtu(dst, mtu);
310 /* Something is about to be wrong... Remember soft error
311 * for the case, if this connection will not able to recover.
313 if (mtu < dst_mtu(dst) && ip_dont_fragment(sk, dst))
314 sk->sk_err_soft = EMSGSIZE;
318 if (inet->pmtudisc != IP_PMTUDISC_DONT &&
319 inet_csk(sk)->icsk_pmtu_cookie > mtu) {
320 tcp_sync_mss(sk, mtu);
322 /* Resend the TCP packet because it's
323 * clear that the old packet has been
324 * dropped. This is the new "fast" path mtu
327 tcp_simple_retransmit(sk);
328 } /* else let the usual retransmit timer handle it */
332 * This routine is called by the ICMP module when it gets some
333 * sort of error condition. If err < 0 then the socket should
334 * be closed and the error returned to the user. If err > 0
335 * it's just the icmp type << 8 | icmp code. After adjustment
336 * header points to the first 8 bytes of the tcp header. We need
337 * to find the appropriate port.
339 * The locking strategy used here is very "optimistic". When
340 * someone else accesses the socket the ICMP is just dropped
341 * and for some paths there is no check at all.
342 * A more general error queue to queue errors for later handling
343 * is probably better.
347 void tcp_v4_err(struct sk_buff *icmp_skb, u32 info)
349 const struct iphdr *iph = (const struct iphdr *)icmp_skb->data;
350 struct tcphdr *th = (struct tcphdr *)(icmp_skb->data + (iph->ihl << 2));
351 struct inet_connection_sock *icsk;
353 struct inet_sock *inet;
354 const int type = icmp_hdr(icmp_skb)->type;
355 const int code = icmp_hdr(icmp_skb)->code;
361 struct net *net = dev_net(icmp_skb->dev);
363 if (icmp_skb->len < (iph->ihl << 2) + 8) {
364 ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS);
368 sk = inet_lookup(net, &tcp_hashinfo, iph->daddr, th->dest,
369 iph->saddr, th->source, inet_iif(icmp_skb));
371 ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS);
374 if (sk->sk_state == TCP_TIME_WAIT) {
375 inet_twsk_put(inet_twsk(sk));
380 /* If too many ICMPs get dropped on busy
381 * servers this needs to be solved differently.
383 if (sock_owned_by_user(sk))
384 NET_INC_STATS_BH(net, LINUX_MIB_LOCKDROPPEDICMPS);
386 if (sk->sk_state == TCP_CLOSE)
389 if (unlikely(iph->ttl < inet_sk(sk)->min_ttl)) {
390 NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP);
396 seq = ntohl(th->seq);
397 if (sk->sk_state != TCP_LISTEN &&
398 !between(seq, tp->snd_una, tp->snd_nxt)) {
399 NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
404 case ICMP_SOURCE_QUENCH:
405 /* Just silently ignore these. */
407 case ICMP_PARAMETERPROB:
410 case ICMP_DEST_UNREACH:
411 if (code > NR_ICMP_UNREACH)
414 if (code == ICMP_FRAG_NEEDED) { /* PMTU discovery (RFC1191) */
415 if (!sock_owned_by_user(sk))
416 do_pmtu_discovery(sk, iph, info);
420 err = icmp_err_convert[code].errno;
421 /* check if icmp_skb allows revert of backoff
422 * (see draft-zimmermann-tcp-lcd) */
423 if (code != ICMP_NET_UNREACH && code != ICMP_HOST_UNREACH)
425 if (seq != tp->snd_una || !icsk->icsk_retransmits ||
429 if (sock_owned_by_user(sk))
432 icsk->icsk_backoff--;
433 inet_csk(sk)->icsk_rto = __tcp_set_rto(tp) <<
437 skb = tcp_write_queue_head(sk);
440 remaining = icsk->icsk_rto - min(icsk->icsk_rto,
441 tcp_time_stamp - TCP_SKB_CB(skb)->when);
444 inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
445 remaining, TCP_RTO_MAX);
447 /* RTO revert clocked out retransmission.
448 * Will retransmit now */
449 tcp_retransmit_timer(sk);
453 case ICMP_TIME_EXCEEDED:
460 switch (sk->sk_state) {
461 struct request_sock *req, **prev;
463 if (sock_owned_by_user(sk))
466 req = inet_csk_search_req(sk, &prev, th->dest,
467 iph->daddr, iph->saddr);
471 /* ICMPs are not backlogged, hence we cannot get
472 an established socket here.
476 if (seq != tcp_rsk(req)->snt_isn) {
477 NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
482 * Still in SYN_RECV, just remove it silently.
483 * There is no good way to pass the error to the newly
484 * created socket, and POSIX does not want network
485 * errors returned from accept().
487 inet_csk_reqsk_queue_drop(sk, req, prev);
491 case TCP_SYN_RECV: /* Cannot happen.
492 It can f.e. if SYNs crossed.
494 if (!sock_owned_by_user(sk)) {
497 sk->sk_error_report(sk);
501 sk->sk_err_soft = err;
506 /* If we've already connected we will keep trying
507 * until we time out, or the user gives up.
509 * rfc1122 4.2.3.9 allows to consider as hard errors
510 * only PROTO_UNREACH and PORT_UNREACH (well, FRAG_FAILED too,
511 * but it is obsoleted by pmtu discovery).
513 * Note, that in modern internet, where routing is unreliable
514 * and in each dark corner broken firewalls sit, sending random
515 * errors ordered by their masters even this two messages finally lose
516 * their original sense (even Linux sends invalid PORT_UNREACHs)
518 * Now we are in compliance with RFCs.
523 if (!sock_owned_by_user(sk) && inet->recverr) {
525 sk->sk_error_report(sk);
526 } else { /* Only an error on timeout */
527 sk->sk_err_soft = err;
535 static void __tcp_v4_send_check(struct sk_buff *skb,
536 __be32 saddr, __be32 daddr)
538 struct tcphdr *th = tcp_hdr(skb);
540 if (skb->ip_summed == CHECKSUM_PARTIAL) {
541 th->check = ~tcp_v4_check(skb->len, saddr, daddr, 0);
542 skb->csum_start = skb_transport_header(skb) - skb->head;
543 skb->csum_offset = offsetof(struct tcphdr, check);
545 th->check = tcp_v4_check(skb->len, saddr, daddr,
552 /* This routine computes an IPv4 TCP checksum. */
553 void tcp_v4_send_check(struct sock *sk, struct sk_buff *skb)
555 struct inet_sock *inet = inet_sk(sk);
557 __tcp_v4_send_check(skb, inet->inet_saddr, inet->inet_daddr);
559 EXPORT_SYMBOL(tcp_v4_send_check);
561 int tcp_v4_gso_send_check(struct sk_buff *skb)
563 const struct iphdr *iph;
566 if (!pskb_may_pull(skb, sizeof(*th)))
573 skb->ip_summed = CHECKSUM_PARTIAL;
574 __tcp_v4_send_check(skb, iph->saddr, iph->daddr);
579 * This routine will send an RST to the other tcp.
581 * Someone asks: why I NEVER use socket parameters (TOS, TTL etc.)
583 * Answer: if a packet caused RST, it is not for a socket
584 * existing in our system, if it is matched to a socket,
585 * it is just duplicate segment or bug in other side's TCP.
586 * So that we build reply only basing on parameters
587 * arrived with segment.
588 * Exception: precedence violation. We do not implement it in any case.
591 static void tcp_v4_send_reset(struct sock *sk, struct sk_buff *skb)
593 struct tcphdr *th = tcp_hdr(skb);
596 #ifdef CONFIG_TCP_MD5SIG
597 __be32 opt[(TCPOLEN_MD5SIG_ALIGNED >> 2)];
600 struct ip_reply_arg arg;
601 #ifdef CONFIG_TCP_MD5SIG
602 struct tcp_md5sig_key *key;
606 /* Never send a reset in response to a reset. */
610 if (skb_rtable(skb)->rt_type != RTN_LOCAL)
613 /* Swap the send and the receive. */
614 memset(&rep, 0, sizeof(rep));
615 rep.th.dest = th->source;
616 rep.th.source = th->dest;
617 rep.th.doff = sizeof(struct tcphdr) / 4;
621 rep.th.seq = th->ack_seq;
624 rep.th.ack_seq = htonl(ntohl(th->seq) + th->syn + th->fin +
625 skb->len - (th->doff << 2));
628 memset(&arg, 0, sizeof(arg));
629 arg.iov[0].iov_base = (unsigned char *)&rep;
630 arg.iov[0].iov_len = sizeof(rep.th);
632 #ifdef CONFIG_TCP_MD5SIG
633 key = sk ? tcp_v4_md5_do_lookup(sk, ip_hdr(skb)->daddr) : NULL;
635 rep.opt[0] = htonl((TCPOPT_NOP << 24) |
637 (TCPOPT_MD5SIG << 8) |
639 /* Update length and the length the header thinks exists */
640 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED;
641 rep.th.doff = arg.iov[0].iov_len / 4;
643 tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[1],
644 key, ip_hdr(skb)->saddr,
645 ip_hdr(skb)->daddr, &rep.th);
648 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
649 ip_hdr(skb)->saddr, /* XXX */
650 arg.iov[0].iov_len, IPPROTO_TCP, 0);
651 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
652 arg.flags = (sk && inet_sk(sk)->transparent) ? IP_REPLY_ARG_NOSRCCHECK : 0;
654 net = dev_net(skb_dst(skb)->dev);
655 ip_send_reply(net->ipv4.tcp_sock, skb, ip_hdr(skb)->saddr,
656 &arg, arg.iov[0].iov_len);
658 TCP_INC_STATS_BH(net, TCP_MIB_OUTSEGS);
659 TCP_INC_STATS_BH(net, TCP_MIB_OUTRSTS);
662 /* The code following below sending ACKs in SYN-RECV and TIME-WAIT states
663 outside socket context is ugly, certainly. What can I do?
666 static void tcp_v4_send_ack(struct sk_buff *skb, u32 seq, u32 ack,
667 u32 win, u32 ts, int oif,
668 struct tcp_md5sig_key *key,
671 struct tcphdr *th = tcp_hdr(skb);
674 __be32 opt[(TCPOLEN_TSTAMP_ALIGNED >> 2)
675 #ifdef CONFIG_TCP_MD5SIG
676 + (TCPOLEN_MD5SIG_ALIGNED >> 2)
680 struct ip_reply_arg arg;
681 struct net *net = dev_net(skb_dst(skb)->dev);
683 memset(&rep.th, 0, sizeof(struct tcphdr));
684 memset(&arg, 0, sizeof(arg));
686 arg.iov[0].iov_base = (unsigned char *)&rep;
687 arg.iov[0].iov_len = sizeof(rep.th);
689 rep.opt[0] = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
690 (TCPOPT_TIMESTAMP << 8) |
692 rep.opt[1] = htonl(tcp_time_stamp);
693 rep.opt[2] = htonl(ts);
694 arg.iov[0].iov_len += TCPOLEN_TSTAMP_ALIGNED;
697 /* Swap the send and the receive. */
698 rep.th.dest = th->source;
699 rep.th.source = th->dest;
700 rep.th.doff = arg.iov[0].iov_len / 4;
701 rep.th.seq = htonl(seq);
702 rep.th.ack_seq = htonl(ack);
704 rep.th.window = htons(win);
706 #ifdef CONFIG_TCP_MD5SIG
708 int offset = (ts) ? 3 : 0;
710 rep.opt[offset++] = htonl((TCPOPT_NOP << 24) |
712 (TCPOPT_MD5SIG << 8) |
714 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED;
715 rep.th.doff = arg.iov[0].iov_len/4;
717 tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[offset],
718 key, ip_hdr(skb)->saddr,
719 ip_hdr(skb)->daddr, &rep.th);
722 arg.flags = reply_flags;
723 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
724 ip_hdr(skb)->saddr, /* XXX */
725 arg.iov[0].iov_len, IPPROTO_TCP, 0);
726 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
728 arg.bound_dev_if = oif;
730 ip_send_reply(net->ipv4.tcp_sock, skb, ip_hdr(skb)->saddr,
731 &arg, arg.iov[0].iov_len);
733 TCP_INC_STATS_BH(net, TCP_MIB_OUTSEGS);
736 static void tcp_v4_timewait_ack(struct sock *sk, struct sk_buff *skb)
738 struct inet_timewait_sock *tw = inet_twsk(sk);
739 struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
741 tcp_v4_send_ack(skb, tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
742 tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
745 tcp_twsk_md5_key(tcptw),
746 tw->tw_transparent ? IP_REPLY_ARG_NOSRCCHECK : 0
752 static void tcp_v4_reqsk_send_ack(struct sock *sk, struct sk_buff *skb,
753 struct request_sock *req)
755 tcp_v4_send_ack(skb, tcp_rsk(req)->snt_isn + 1,
756 tcp_rsk(req)->rcv_isn + 1, req->rcv_wnd,
759 tcp_v4_md5_do_lookup(sk, ip_hdr(skb)->daddr),
760 inet_rsk(req)->no_srccheck ? IP_REPLY_ARG_NOSRCCHECK : 0);
764 * Send a SYN-ACK after having received a SYN.
765 * This still operates on a request_sock only, not on a big
768 static int tcp_v4_send_synack(struct sock *sk, struct dst_entry *dst,
769 struct request_sock *req,
770 struct request_values *rvp)
772 const struct inet_request_sock *ireq = inet_rsk(req);
775 struct sk_buff * skb;
777 /* First, grab a route. */
778 if (!dst && (dst = inet_csk_route_req(sk, &fl4, req)) == NULL)
781 skb = tcp_make_synack(sk, dst, req, rvp);
784 __tcp_v4_send_check(skb, ireq->loc_addr, ireq->rmt_addr);
786 err = ip_build_and_send_pkt(skb, sk, ireq->loc_addr,
789 err = net_xmit_eval(err);
796 static int tcp_v4_rtx_synack(struct sock *sk, struct request_sock *req,
797 struct request_values *rvp)
799 TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_RETRANSSEGS);
800 return tcp_v4_send_synack(sk, NULL, req, rvp);
804 * IPv4 request_sock destructor.
806 static void tcp_v4_reqsk_destructor(struct request_sock *req)
808 kfree(inet_rsk(req)->opt);
811 static void syn_flood_warning(const struct sk_buff *skb)
815 #ifdef CONFIG_SYN_COOKIES
816 if (sysctl_tcp_syncookies)
817 msg = "Sending cookies";
820 msg = "Dropping request";
822 pr_info("TCP: Possible SYN flooding on port %d. %s.\n",
823 ntohs(tcp_hdr(skb)->dest), msg);
827 * Save and compile IPv4 options into the request_sock if needed.
829 static struct ip_options_rcu *tcp_v4_save_options(struct sock *sk,
832 const struct ip_options *opt = &(IPCB(skb)->opt);
833 struct ip_options_rcu *dopt = NULL;
835 if (opt && opt->optlen) {
836 int opt_size = sizeof(*dopt) + opt->optlen;
838 dopt = kmalloc(opt_size, GFP_ATOMIC);
840 if (ip_options_echo(&dopt->opt, skb)) {
849 #ifdef CONFIG_TCP_MD5SIG
851 * RFC2385 MD5 checksumming requires a mapping of
852 * IP address->MD5 Key.
853 * We need to maintain these in the sk structure.
856 /* Find the Key structure for an address. */
857 static struct tcp_md5sig_key *
858 tcp_v4_md5_do_lookup(struct sock *sk, __be32 addr)
860 struct tcp_sock *tp = tcp_sk(sk);
863 if (!tp->md5sig_info || !tp->md5sig_info->entries4)
865 for (i = 0; i < tp->md5sig_info->entries4; i++) {
866 if (tp->md5sig_info->keys4[i].addr == addr)
867 return &tp->md5sig_info->keys4[i].base;
872 struct tcp_md5sig_key *tcp_v4_md5_lookup(struct sock *sk,
873 struct sock *addr_sk)
875 return tcp_v4_md5_do_lookup(sk, inet_sk(addr_sk)->inet_daddr);
877 EXPORT_SYMBOL(tcp_v4_md5_lookup);
879 static struct tcp_md5sig_key *tcp_v4_reqsk_md5_lookup(struct sock *sk,
880 struct request_sock *req)
882 return tcp_v4_md5_do_lookup(sk, inet_rsk(req)->rmt_addr);
885 /* This can be called on a newly created socket, from other files */
886 int tcp_v4_md5_do_add(struct sock *sk, __be32 addr,
887 u8 *newkey, u8 newkeylen)
889 /* Add Key to the list */
890 struct tcp_md5sig_key *key;
891 struct tcp_sock *tp = tcp_sk(sk);
892 struct tcp4_md5sig_key *keys;
894 key = tcp_v4_md5_do_lookup(sk, addr);
896 /* Pre-existing entry - just update that one. */
899 key->keylen = newkeylen;
901 struct tcp_md5sig_info *md5sig;
903 if (!tp->md5sig_info) {
904 tp->md5sig_info = kzalloc(sizeof(*tp->md5sig_info),
906 if (!tp->md5sig_info) {
910 sk_nocaps_add(sk, NETIF_F_GSO_MASK);
912 if (tcp_alloc_md5sig_pool(sk) == NULL) {
916 md5sig = tp->md5sig_info;
918 if (md5sig->alloced4 == md5sig->entries4) {
919 keys = kmalloc((sizeof(*keys) *
920 (md5sig->entries4 + 1)), GFP_ATOMIC);
923 tcp_free_md5sig_pool();
927 if (md5sig->entries4)
928 memcpy(keys, md5sig->keys4,
929 sizeof(*keys) * md5sig->entries4);
931 /* Free old key list, and reference new one */
932 kfree(md5sig->keys4);
933 md5sig->keys4 = keys;
937 md5sig->keys4[md5sig->entries4 - 1].addr = addr;
938 md5sig->keys4[md5sig->entries4 - 1].base.key = newkey;
939 md5sig->keys4[md5sig->entries4 - 1].base.keylen = newkeylen;
943 EXPORT_SYMBOL(tcp_v4_md5_do_add);
945 static int tcp_v4_md5_add_func(struct sock *sk, struct sock *addr_sk,
946 u8 *newkey, u8 newkeylen)
948 return tcp_v4_md5_do_add(sk, inet_sk(addr_sk)->inet_daddr,
952 int tcp_v4_md5_do_del(struct sock *sk, __be32 addr)
954 struct tcp_sock *tp = tcp_sk(sk);
957 for (i = 0; i < tp->md5sig_info->entries4; i++) {
958 if (tp->md5sig_info->keys4[i].addr == addr) {
960 kfree(tp->md5sig_info->keys4[i].base.key);
961 tp->md5sig_info->entries4--;
963 if (tp->md5sig_info->entries4 == 0) {
964 kfree(tp->md5sig_info->keys4);
965 tp->md5sig_info->keys4 = NULL;
966 tp->md5sig_info->alloced4 = 0;
967 } else if (tp->md5sig_info->entries4 != i) {
968 /* Need to do some manipulation */
969 memmove(&tp->md5sig_info->keys4[i],
970 &tp->md5sig_info->keys4[i+1],
971 (tp->md5sig_info->entries4 - i) *
972 sizeof(struct tcp4_md5sig_key));
974 tcp_free_md5sig_pool();
980 EXPORT_SYMBOL(tcp_v4_md5_do_del);
982 static void tcp_v4_clear_md5_list(struct sock *sk)
984 struct tcp_sock *tp = tcp_sk(sk);
986 /* Free each key, then the set of key keys,
987 * the crypto element, and then decrement our
988 * hold on the last resort crypto.
990 if (tp->md5sig_info->entries4) {
992 for (i = 0; i < tp->md5sig_info->entries4; i++)
993 kfree(tp->md5sig_info->keys4[i].base.key);
994 tp->md5sig_info->entries4 = 0;
995 tcp_free_md5sig_pool();
997 if (tp->md5sig_info->keys4) {
998 kfree(tp->md5sig_info->keys4);
999 tp->md5sig_info->keys4 = NULL;
1000 tp->md5sig_info->alloced4 = 0;
1004 static int tcp_v4_parse_md5_keys(struct sock *sk, char __user *optval,
1007 struct tcp_md5sig cmd;
1008 struct sockaddr_in *sin = (struct sockaddr_in *)&cmd.tcpm_addr;
1011 if (optlen < sizeof(cmd))
1014 if (copy_from_user(&cmd, optval, sizeof(cmd)))
1017 if (sin->sin_family != AF_INET)
1020 if (!cmd.tcpm_key || !cmd.tcpm_keylen) {
1021 if (!tcp_sk(sk)->md5sig_info)
1023 return tcp_v4_md5_do_del(sk, sin->sin_addr.s_addr);
1026 if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN)
1029 if (!tcp_sk(sk)->md5sig_info) {
1030 struct tcp_sock *tp = tcp_sk(sk);
1031 struct tcp_md5sig_info *p;
1033 p = kzalloc(sizeof(*p), sk->sk_allocation);
1037 tp->md5sig_info = p;
1038 sk_nocaps_add(sk, NETIF_F_GSO_MASK);
1041 newkey = kmemdup(cmd.tcpm_key, cmd.tcpm_keylen, sk->sk_allocation);
1044 return tcp_v4_md5_do_add(sk, sin->sin_addr.s_addr,
1045 newkey, cmd.tcpm_keylen);
1048 static int tcp_v4_md5_hash_pseudoheader(struct tcp_md5sig_pool *hp,
1049 __be32 daddr, __be32 saddr, int nbytes)
1051 struct tcp4_pseudohdr *bp;
1052 struct scatterlist sg;
1054 bp = &hp->md5_blk.ip4;
1057 * 1. the TCP pseudo-header (in the order: source IP address,
1058 * destination IP address, zero-padded protocol number, and
1064 bp->protocol = IPPROTO_TCP;
1065 bp->len = cpu_to_be16(nbytes);
1067 sg_init_one(&sg, bp, sizeof(*bp));
1068 return crypto_hash_update(&hp->md5_desc, &sg, sizeof(*bp));
1071 static int tcp_v4_md5_hash_hdr(char *md5_hash, struct tcp_md5sig_key *key,
1072 __be32 daddr, __be32 saddr, struct tcphdr *th)
1074 struct tcp_md5sig_pool *hp;
1075 struct hash_desc *desc;
1077 hp = tcp_get_md5sig_pool();
1079 goto clear_hash_noput;
1080 desc = &hp->md5_desc;
1082 if (crypto_hash_init(desc))
1084 if (tcp_v4_md5_hash_pseudoheader(hp, daddr, saddr, th->doff << 2))
1086 if (tcp_md5_hash_header(hp, th))
1088 if (tcp_md5_hash_key(hp, key))
1090 if (crypto_hash_final(desc, md5_hash))
1093 tcp_put_md5sig_pool();
1097 tcp_put_md5sig_pool();
1099 memset(md5_hash, 0, 16);
1103 int tcp_v4_md5_hash_skb(char *md5_hash, struct tcp_md5sig_key *key,
1104 struct sock *sk, struct request_sock *req,
1105 struct sk_buff *skb)
1107 struct tcp_md5sig_pool *hp;
1108 struct hash_desc *desc;
1109 struct tcphdr *th = tcp_hdr(skb);
1110 __be32 saddr, daddr;
1113 saddr = inet_sk(sk)->inet_saddr;
1114 daddr = inet_sk(sk)->inet_daddr;
1116 saddr = inet_rsk(req)->loc_addr;
1117 daddr = inet_rsk(req)->rmt_addr;
1119 const struct iphdr *iph = ip_hdr(skb);
1124 hp = tcp_get_md5sig_pool();
1126 goto clear_hash_noput;
1127 desc = &hp->md5_desc;
1129 if (crypto_hash_init(desc))
1132 if (tcp_v4_md5_hash_pseudoheader(hp, daddr, saddr, skb->len))
1134 if (tcp_md5_hash_header(hp, th))
1136 if (tcp_md5_hash_skb_data(hp, skb, th->doff << 2))
1138 if (tcp_md5_hash_key(hp, key))
1140 if (crypto_hash_final(desc, md5_hash))
1143 tcp_put_md5sig_pool();
1147 tcp_put_md5sig_pool();
1149 memset(md5_hash, 0, 16);
1152 EXPORT_SYMBOL(tcp_v4_md5_hash_skb);
1154 static int tcp_v4_inbound_md5_hash(struct sock *sk, struct sk_buff *skb)
1157 * This gets called for each TCP segment that arrives
1158 * so we want to be efficient.
1159 * We have 3 drop cases:
1160 * o No MD5 hash and one expected.
1161 * o MD5 hash and we're not expecting one.
1162 * o MD5 hash and its wrong.
1164 __u8 *hash_location = NULL;
1165 struct tcp_md5sig_key *hash_expected;
1166 const struct iphdr *iph = ip_hdr(skb);
1167 struct tcphdr *th = tcp_hdr(skb);
1169 unsigned char newhash[16];
1171 hash_expected = tcp_v4_md5_do_lookup(sk, iph->saddr);
1172 hash_location = tcp_parse_md5sig_option(th);
1174 /* We've parsed the options - do we have a hash? */
1175 if (!hash_expected && !hash_location)
1178 if (hash_expected && !hash_location) {
1179 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5NOTFOUND);
1183 if (!hash_expected && hash_location) {
1184 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5UNEXPECTED);
1188 /* Okay, so this is hash_expected and hash_location -
1189 * so we need to calculate the checksum.
1191 genhash = tcp_v4_md5_hash_skb(newhash,
1195 if (genhash || memcmp(hash_location, newhash, 16) != 0) {
1196 if (net_ratelimit()) {
1197 printk(KERN_INFO "MD5 Hash failed for (%pI4, %d)->(%pI4, %d)%s\n",
1198 &iph->saddr, ntohs(th->source),
1199 &iph->daddr, ntohs(th->dest),
1200 genhash ? " tcp_v4_calc_md5_hash failed" : "");
1209 struct request_sock_ops tcp_request_sock_ops __read_mostly = {
1211 .obj_size = sizeof(struct tcp_request_sock),
1212 .rtx_syn_ack = tcp_v4_rtx_synack,
1213 .send_ack = tcp_v4_reqsk_send_ack,
1214 .destructor = tcp_v4_reqsk_destructor,
1215 .send_reset = tcp_v4_send_reset,
1216 .syn_ack_timeout = tcp_syn_ack_timeout,
1219 #ifdef CONFIG_TCP_MD5SIG
1220 static const struct tcp_request_sock_ops tcp_request_sock_ipv4_ops = {
1221 .md5_lookup = tcp_v4_reqsk_md5_lookup,
1222 .calc_md5_hash = tcp_v4_md5_hash_skb,
1226 int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
1228 struct tcp_extend_values tmp_ext;
1229 struct tcp_options_received tmp_opt;
1231 struct request_sock *req;
1232 struct inet_request_sock *ireq;
1233 struct tcp_sock *tp = tcp_sk(sk);
1234 struct dst_entry *dst = NULL;
1235 __be32 saddr = ip_hdr(skb)->saddr;
1236 __be32 daddr = ip_hdr(skb)->daddr;
1237 __u32 isn = TCP_SKB_CB(skb)->when;
1238 #ifdef CONFIG_SYN_COOKIES
1239 int want_cookie = 0;
1241 #define want_cookie 0 /* Argh, why doesn't gcc optimize this :( */
1244 /* Never answer to SYNs send to broadcast or multicast */
1245 if (skb_rtable(skb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
1248 /* TW buckets are converted to open requests without
1249 * limitations, they conserve resources and peer is
1250 * evidently real one.
1252 if (inet_csk_reqsk_queue_is_full(sk) && !isn) {
1253 if (net_ratelimit())
1254 syn_flood_warning(skb);
1255 #ifdef CONFIG_SYN_COOKIES
1256 if (sysctl_tcp_syncookies) {
1263 /* Accept backlog is full. If we have already queued enough
1264 * of warm entries in syn queue, drop request. It is better than
1265 * clogging syn queue with openreqs with exponentially increasing
1268 if (sk_acceptq_is_full(sk) && inet_csk_reqsk_queue_young(sk) > 1)
1271 req = inet_reqsk_alloc(&tcp_request_sock_ops);
1275 #ifdef CONFIG_TCP_MD5SIG
1276 tcp_rsk(req)->af_specific = &tcp_request_sock_ipv4_ops;
1279 tcp_clear_options(&tmp_opt);
1280 tmp_opt.mss_clamp = TCP_MSS_DEFAULT;
1281 tmp_opt.user_mss = tp->rx_opt.user_mss;
1282 tcp_parse_options(skb, &tmp_opt, &hash_location, 0);
1284 if (tmp_opt.cookie_plus > 0 &&
1285 tmp_opt.saw_tstamp &&
1286 !tp->rx_opt.cookie_out_never &&
1287 (sysctl_tcp_cookie_size > 0 ||
1288 (tp->cookie_values != NULL &&
1289 tp->cookie_values->cookie_desired > 0))) {
1291 u32 *mess = &tmp_ext.cookie_bakery[COOKIE_DIGEST_WORDS];
1292 int l = tmp_opt.cookie_plus - TCPOLEN_COOKIE_BASE;
1294 if (tcp_cookie_generator(&tmp_ext.cookie_bakery[0]) != 0)
1295 goto drop_and_release;
1297 /* Secret recipe starts with IP addresses */
1298 *mess++ ^= (__force u32)daddr;
1299 *mess++ ^= (__force u32)saddr;
1301 /* plus variable length Initiator Cookie */
1304 *c++ ^= *hash_location++;
1306 #ifdef CONFIG_SYN_COOKIES
1307 want_cookie = 0; /* not our kind of cookie */
1309 tmp_ext.cookie_out_never = 0; /* false */
1310 tmp_ext.cookie_plus = tmp_opt.cookie_plus;
1311 } else if (!tp->rx_opt.cookie_in_always) {
1312 /* redundant indications, but ensure initialization. */
1313 tmp_ext.cookie_out_never = 1; /* true */
1314 tmp_ext.cookie_plus = 0;
1316 goto drop_and_release;
1318 tmp_ext.cookie_in_always = tp->rx_opt.cookie_in_always;
1320 if (want_cookie && !tmp_opt.saw_tstamp)
1321 tcp_clear_options(&tmp_opt);
1323 tmp_opt.tstamp_ok = tmp_opt.saw_tstamp;
1324 tcp_openreq_init(req, &tmp_opt, skb);
1326 ireq = inet_rsk(req);
1327 ireq->loc_addr = daddr;
1328 ireq->rmt_addr = saddr;
1329 ireq->no_srccheck = inet_sk(sk)->transparent;
1330 ireq->opt = tcp_v4_save_options(sk, skb);
1332 if (security_inet_conn_request(sk, skb, req))
1335 if (!want_cookie || tmp_opt.tstamp_ok)
1336 TCP_ECN_create_request(req, tcp_hdr(skb));
1339 isn = cookie_v4_init_sequence(sk, skb, &req->mss);
1340 req->cookie_ts = tmp_opt.tstamp_ok;
1342 struct inet_peer *peer = NULL;
1345 /* VJ's idea. We save last timestamp seen
1346 * from the destination in peer table, when entering
1347 * state TIME-WAIT, and check against it before
1348 * accepting new connection request.
1350 * If "isn" is not zero, this request hit alive
1351 * timewait bucket, so that all the necessary checks
1352 * are made in the function processing timewait state.
1354 if (tmp_opt.saw_tstamp &&
1355 tcp_death_row.sysctl_tw_recycle &&
1356 (dst = inet_csk_route_req(sk, &fl4, req)) != NULL &&
1357 fl4.daddr == saddr &&
1358 (peer = rt_get_peer((struct rtable *)dst, fl4.daddr)) != NULL) {
1359 inet_peer_refcheck(peer);
1360 if ((u32)get_seconds() - peer->tcp_ts_stamp < TCP_PAWS_MSL &&
1361 (s32)(peer->tcp_ts - req->ts_recent) >
1363 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_PAWSPASSIVEREJECTED);
1364 goto drop_and_release;
1367 /* Kill the following clause, if you dislike this way. */
1368 else if (!sysctl_tcp_syncookies &&
1369 (sysctl_max_syn_backlog - inet_csk_reqsk_queue_len(sk) <
1370 (sysctl_max_syn_backlog >> 2)) &&
1371 (!peer || !peer->tcp_ts_stamp) &&
1372 (!dst || !dst_metric(dst, RTAX_RTT))) {
1373 /* Without syncookies last quarter of
1374 * backlog is filled with destinations,
1375 * proven to be alive.
1376 * It means that we continue to communicate
1377 * to destinations, already remembered
1378 * to the moment of synflood.
1380 LIMIT_NETDEBUG(KERN_DEBUG "TCP: drop open request from %pI4/%u\n",
1381 &saddr, ntohs(tcp_hdr(skb)->source));
1382 goto drop_and_release;
1385 isn = tcp_v4_init_sequence(skb);
1387 tcp_rsk(req)->snt_isn = isn;
1389 if (tcp_v4_send_synack(sk, dst, req,
1390 (struct request_values *)&tmp_ext) ||
1394 inet_csk_reqsk_queue_hash_add(sk, req, TCP_TIMEOUT_INIT);
1404 EXPORT_SYMBOL(tcp_v4_conn_request);
1408 * The three way handshake has completed - we got a valid synack -
1409 * now create the new socket.
1411 struct sock *tcp_v4_syn_recv_sock(struct sock *sk, struct sk_buff *skb,
1412 struct request_sock *req,
1413 struct dst_entry *dst)
1415 struct inet_request_sock *ireq;
1416 struct inet_sock *newinet;
1417 struct tcp_sock *newtp;
1419 #ifdef CONFIG_TCP_MD5SIG
1420 struct tcp_md5sig_key *key;
1422 struct ip_options_rcu *inet_opt;
1424 if (sk_acceptq_is_full(sk))
1427 newsk = tcp_create_openreq_child(sk, req, skb);
1431 newsk->sk_gso_type = SKB_GSO_TCPV4;
1433 newtp = tcp_sk(newsk);
1434 newinet = inet_sk(newsk);
1435 ireq = inet_rsk(req);
1436 newinet->inet_daddr = ireq->rmt_addr;
1437 newinet->inet_rcv_saddr = ireq->loc_addr;
1438 newinet->inet_saddr = ireq->loc_addr;
1439 inet_opt = ireq->opt;
1440 rcu_assign_pointer(newinet->inet_opt, inet_opt);
1442 newinet->mc_index = inet_iif(skb);
1443 newinet->mc_ttl = ip_hdr(skb)->ttl;
1444 inet_csk(newsk)->icsk_ext_hdr_len = 0;
1446 inet_csk(newsk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
1447 newinet->inet_id = newtp->write_seq ^ jiffies;
1449 if (!dst && (dst = inet_csk_route_child_sock(sk, newsk, req)) == NULL)
1452 sk_setup_caps(newsk, dst);
1454 tcp_mtup_init(newsk);
1455 tcp_sync_mss(newsk, dst_mtu(dst));
1456 newtp->advmss = dst_metric_advmss(dst);
1457 if (tcp_sk(sk)->rx_opt.user_mss &&
1458 tcp_sk(sk)->rx_opt.user_mss < newtp->advmss)
1459 newtp->advmss = tcp_sk(sk)->rx_opt.user_mss;
1461 tcp_initialize_rcv_mss(newsk);
1463 #ifdef CONFIG_TCP_MD5SIG
1464 /* Copy over the MD5 key from the original socket */
1465 key = tcp_v4_md5_do_lookup(sk, newinet->inet_daddr);
1468 * We're using one, so create a matching key
1469 * on the newsk structure. If we fail to get
1470 * memory, then we end up not copying the key
1473 char *newkey = kmemdup(key->key, key->keylen, GFP_ATOMIC);
1475 tcp_v4_md5_do_add(newsk, newinet->inet_daddr,
1476 newkey, key->keylen);
1477 sk_nocaps_add(newsk, NETIF_F_GSO_MASK);
1481 if (__inet_inherit_port(sk, newsk) < 0)
1483 __inet_hash_nolisten(newsk, NULL);
1488 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
1492 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
1498 EXPORT_SYMBOL(tcp_v4_syn_recv_sock);
1500 static struct sock *tcp_v4_hnd_req(struct sock *sk, struct sk_buff *skb)
1502 struct tcphdr *th = tcp_hdr(skb);
1503 const struct iphdr *iph = ip_hdr(skb);
1505 struct request_sock **prev;
1506 /* Find possible connection requests. */
1507 struct request_sock *req = inet_csk_search_req(sk, &prev, th->source,
1508 iph->saddr, iph->daddr);
1510 return tcp_check_req(sk, skb, req, prev);
1512 nsk = inet_lookup_established(sock_net(sk), &tcp_hashinfo, iph->saddr,
1513 th->source, iph->daddr, th->dest, inet_iif(skb));
1516 if (nsk->sk_state != TCP_TIME_WAIT) {
1520 inet_twsk_put(inet_twsk(nsk));
1524 #ifdef CONFIG_SYN_COOKIES
1526 sk = cookie_v4_check(sk, skb, &(IPCB(skb)->opt));
1531 static __sum16 tcp_v4_checksum_init(struct sk_buff *skb)
1533 const struct iphdr *iph = ip_hdr(skb);
1535 if (skb->ip_summed == CHECKSUM_COMPLETE) {
1536 if (!tcp_v4_check(skb->len, iph->saddr,
1537 iph->daddr, skb->csum)) {
1538 skb->ip_summed = CHECKSUM_UNNECESSARY;
1543 skb->csum = csum_tcpudp_nofold(iph->saddr, iph->daddr,
1544 skb->len, IPPROTO_TCP, 0);
1546 if (skb->len <= 76) {
1547 return __skb_checksum_complete(skb);
1553 /* The socket must have it's spinlock held when we get
1556 * We have a potential double-lock case here, so even when
1557 * doing backlog processing we use the BH locking scheme.
1558 * This is because we cannot sleep with the original spinlock
1561 int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
1564 #ifdef CONFIG_TCP_MD5SIG
1566 * We really want to reject the packet as early as possible
1568 * o We're expecting an MD5'd packet and this is no MD5 tcp option
1569 * o There is an MD5 option and we're not expecting one
1571 if (tcp_v4_inbound_md5_hash(sk, skb))
1575 if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
1576 sock_rps_save_rxhash(sk, skb->rxhash);
1577 if (tcp_rcv_established(sk, skb, tcp_hdr(skb), skb->len)) {
1584 if (skb->len < tcp_hdrlen(skb) || tcp_checksum_complete(skb))
1587 if (sk->sk_state == TCP_LISTEN) {
1588 struct sock *nsk = tcp_v4_hnd_req(sk, skb);
1593 sock_rps_save_rxhash(nsk, skb->rxhash);
1594 if (tcp_child_process(sk, nsk, skb)) {
1601 sock_rps_save_rxhash(sk, skb->rxhash);
1603 if (tcp_rcv_state_process(sk, skb, tcp_hdr(skb), skb->len)) {
1610 tcp_v4_send_reset(rsk, skb);
1613 /* Be careful here. If this function gets more complicated and
1614 * gcc suffers from register pressure on the x86, sk (in %ebx)
1615 * might be destroyed here. This current version compiles correctly,
1616 * but you have been warned.
1621 TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_INERRS);
1624 EXPORT_SYMBOL(tcp_v4_do_rcv);
1630 int tcp_v4_rcv(struct sk_buff *skb)
1632 const struct iphdr *iph;
1636 struct net *net = dev_net(skb->dev);
1638 if (skb->pkt_type != PACKET_HOST)
1641 /* Count it even if it's bad */
1642 TCP_INC_STATS_BH(net, TCP_MIB_INSEGS);
1644 if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
1649 if (th->doff < sizeof(struct tcphdr) / 4)
1651 if (!pskb_may_pull(skb, th->doff * 4))
1654 /* An explanation is required here, I think.
1655 * Packet length and doff are validated by header prediction,
1656 * provided case of th->doff==0 is eliminated.
1657 * So, we defer the checks. */
1658 if (!skb_csum_unnecessary(skb) && tcp_v4_checksum_init(skb))
1663 TCP_SKB_CB(skb)->seq = ntohl(th->seq);
1664 TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
1665 skb->len - th->doff * 4);
1666 TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
1667 TCP_SKB_CB(skb)->when = 0;
1668 TCP_SKB_CB(skb)->flags = iph->tos;
1669 TCP_SKB_CB(skb)->sacked = 0;
1671 sk = __inet_lookup_skb(&tcp_hashinfo, skb, th->source, th->dest);
1676 if (sk->sk_state == TCP_TIME_WAIT)
1679 if (unlikely(iph->ttl < inet_sk(sk)->min_ttl)) {
1680 NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP);
1681 goto discard_and_relse;
1684 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
1685 goto discard_and_relse;
1688 if (sk_filter(sk, skb))
1689 goto discard_and_relse;
1693 bh_lock_sock_nested(sk);
1695 if (!sock_owned_by_user(sk)) {
1696 #ifdef CONFIG_NET_DMA
1697 struct tcp_sock *tp = tcp_sk(sk);
1698 if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list)
1699 tp->ucopy.dma_chan = dma_find_channel(DMA_MEMCPY);
1700 if (tp->ucopy.dma_chan)
1701 ret = tcp_v4_do_rcv(sk, skb);
1705 if (!tcp_prequeue(sk, skb))
1706 ret = tcp_v4_do_rcv(sk, skb);
1708 } else if (unlikely(sk_add_backlog(sk, skb))) {
1710 NET_INC_STATS_BH(net, LINUX_MIB_TCPBACKLOGDROP);
1711 goto discard_and_relse;
1720 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
1723 if (skb->len < (th->doff << 2) || tcp_checksum_complete(skb)) {
1725 TCP_INC_STATS_BH(net, TCP_MIB_INERRS);
1727 tcp_v4_send_reset(NULL, skb);
1731 /* Discard frame. */
1740 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
1741 inet_twsk_put(inet_twsk(sk));
1745 if (skb->len < (th->doff << 2) || tcp_checksum_complete(skb)) {
1746 TCP_INC_STATS_BH(net, TCP_MIB_INERRS);
1747 inet_twsk_put(inet_twsk(sk));
1750 switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) {
1752 struct sock *sk2 = inet_lookup_listener(dev_net(skb->dev),
1754 iph->daddr, th->dest,
1757 inet_twsk_deschedule(inet_twsk(sk), &tcp_death_row);
1758 inet_twsk_put(inet_twsk(sk));
1762 /* Fall through to ACK */
1765 tcp_v4_timewait_ack(sk, skb);
1769 case TCP_TW_SUCCESS:;
1774 struct inet_peer *tcp_v4_get_peer(struct sock *sk, bool *release_it)
1776 struct rtable *rt = (struct rtable *) __sk_dst_get(sk);
1777 struct inet_sock *inet = inet_sk(sk);
1778 struct inet_peer *peer;
1781 inet->cork.fl.u.ip4.daddr != inet->inet_daddr) {
1782 peer = inet_getpeer_v4(inet->inet_daddr, 1);
1786 rt_bind_peer(rt, inet->inet_daddr, 1);
1788 *release_it = false;
1793 EXPORT_SYMBOL(tcp_v4_get_peer);
1795 void *tcp_v4_tw_get_peer(struct sock *sk)
1797 struct inet_timewait_sock *tw = inet_twsk(sk);
1799 return inet_getpeer_v4(tw->tw_daddr, 1);
1801 EXPORT_SYMBOL(tcp_v4_tw_get_peer);
1803 static struct timewait_sock_ops tcp_timewait_sock_ops = {
1804 .twsk_obj_size = sizeof(struct tcp_timewait_sock),
1805 .twsk_unique = tcp_twsk_unique,
1806 .twsk_destructor= tcp_twsk_destructor,
1807 .twsk_getpeer = tcp_v4_tw_get_peer,
1810 const struct inet_connection_sock_af_ops ipv4_specific = {
1811 .queue_xmit = ip_queue_xmit,
1812 .send_check = tcp_v4_send_check,
1813 .rebuild_header = inet_sk_rebuild_header,
1814 .conn_request = tcp_v4_conn_request,
1815 .syn_recv_sock = tcp_v4_syn_recv_sock,
1816 .get_peer = tcp_v4_get_peer,
1817 .net_header_len = sizeof(struct iphdr),
1818 .setsockopt = ip_setsockopt,
1819 .getsockopt = ip_getsockopt,
1820 .addr2sockaddr = inet_csk_addr2sockaddr,
1821 .sockaddr_len = sizeof(struct sockaddr_in),
1822 .bind_conflict = inet_csk_bind_conflict,
1823 #ifdef CONFIG_COMPAT
1824 .compat_setsockopt = compat_ip_setsockopt,
1825 .compat_getsockopt = compat_ip_getsockopt,
1828 EXPORT_SYMBOL(ipv4_specific);
1830 #ifdef CONFIG_TCP_MD5SIG
1831 static const struct tcp_sock_af_ops tcp_sock_ipv4_specific = {
1832 .md5_lookup = tcp_v4_md5_lookup,
1833 .calc_md5_hash = tcp_v4_md5_hash_skb,
1834 .md5_add = tcp_v4_md5_add_func,
1835 .md5_parse = tcp_v4_parse_md5_keys,
1839 /* NOTE: A lot of things set to zero explicitly by call to
1840 * sk_alloc() so need not be done here.
1842 static int tcp_v4_init_sock(struct sock *sk)
1844 struct inet_connection_sock *icsk = inet_csk(sk);
1845 struct tcp_sock *tp = tcp_sk(sk);
1847 skb_queue_head_init(&tp->out_of_order_queue);
1848 tcp_init_xmit_timers(sk);
1849 tcp_prequeue_init(tp);
1851 icsk->icsk_rto = TCP_TIMEOUT_INIT;
1852 tp->mdev = TCP_TIMEOUT_INIT;
1854 /* So many TCP implementations out there (incorrectly) count the
1855 * initial SYN frame in their delayed-ACK and congestion control
1856 * algorithms that we must have the following bandaid to talk
1857 * efficiently to them. -DaveM
1861 /* See draft-stevens-tcpca-spec-01 for discussion of the
1862 * initialization of these values.
1864 tp->snd_ssthresh = TCP_INFINITE_SSTHRESH;
1865 tp->snd_cwnd_clamp = ~0;
1866 tp->mss_cache = TCP_MSS_DEFAULT;
1868 tp->reordering = sysctl_tcp_reordering;
1869 icsk->icsk_ca_ops = &tcp_init_congestion_ops;
1871 sk->sk_state = TCP_CLOSE;
1873 sk->sk_write_space = sk_stream_write_space;
1874 sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
1876 icsk->icsk_af_ops = &ipv4_specific;
1877 icsk->icsk_sync_mss = tcp_sync_mss;
1878 #ifdef CONFIG_TCP_MD5SIG
1879 tp->af_specific = &tcp_sock_ipv4_specific;
1882 /* TCP Cookie Transactions */
1883 if (sysctl_tcp_cookie_size > 0) {
1884 /* Default, cookies without s_data_payload. */
1886 kzalloc(sizeof(*tp->cookie_values),
1888 if (tp->cookie_values != NULL)
1889 kref_init(&tp->cookie_values->kref);
1891 /* Presumed zeroed, in order of appearance:
1892 * cookie_in_always, cookie_out_never,
1893 * s_data_constant, s_data_in, s_data_out
1895 sk->sk_sndbuf = sysctl_tcp_wmem[1];
1896 sk->sk_rcvbuf = sysctl_tcp_rmem[1];
1899 percpu_counter_inc(&tcp_sockets_allocated);
1905 void tcp_v4_destroy_sock(struct sock *sk)
1907 struct tcp_sock *tp = tcp_sk(sk);
1909 tcp_clear_xmit_timers(sk);
1911 tcp_cleanup_congestion_control(sk);
1913 /* Cleanup up the write buffer. */
1914 tcp_write_queue_purge(sk);
1916 /* Cleans up our, hopefully empty, out_of_order_queue. */
1917 __skb_queue_purge(&tp->out_of_order_queue);
1919 #ifdef CONFIG_TCP_MD5SIG
1920 /* Clean up the MD5 key list, if any */
1921 if (tp->md5sig_info) {
1922 tcp_v4_clear_md5_list(sk);
1923 kfree(tp->md5sig_info);
1924 tp->md5sig_info = NULL;
1928 #ifdef CONFIG_NET_DMA
1929 /* Cleans up our sk_async_wait_queue */
1930 __skb_queue_purge(&sk->sk_async_wait_queue);
1933 /* Clean prequeue, it must be empty really */
1934 __skb_queue_purge(&tp->ucopy.prequeue);
1936 /* Clean up a referenced TCP bind bucket. */
1937 if (inet_csk(sk)->icsk_bind_hash)
1941 * If sendmsg cached page exists, toss it.
1943 if (sk->sk_sndmsg_page) {
1944 __free_page(sk->sk_sndmsg_page);
1945 sk->sk_sndmsg_page = NULL;
1948 /* TCP Cookie Transactions */
1949 if (tp->cookie_values != NULL) {
1950 kref_put(&tp->cookie_values->kref,
1951 tcp_cookie_values_release);
1952 tp->cookie_values = NULL;
1955 percpu_counter_dec(&tcp_sockets_allocated);
1957 EXPORT_SYMBOL(tcp_v4_destroy_sock);
1959 #ifdef CONFIG_PROC_FS
1960 /* Proc filesystem TCP sock list dumping. */
1962 static inline struct inet_timewait_sock *tw_head(struct hlist_nulls_head *head)
1964 return hlist_nulls_empty(head) ? NULL :
1965 list_entry(head->first, struct inet_timewait_sock, tw_node);
1968 static inline struct inet_timewait_sock *tw_next(struct inet_timewait_sock *tw)
1970 return !is_a_nulls(tw->tw_node.next) ?
1971 hlist_nulls_entry(tw->tw_node.next, typeof(*tw), tw_node) : NULL;
1975 * Get next listener socket follow cur. If cur is NULL, get first socket
1976 * starting from bucket given in st->bucket; when st->bucket is zero the
1977 * very first socket in the hash table is returned.
1979 static void *listening_get_next(struct seq_file *seq, void *cur)
1981 struct inet_connection_sock *icsk;
1982 struct hlist_nulls_node *node;
1983 struct sock *sk = cur;
1984 struct inet_listen_hashbucket *ilb;
1985 struct tcp_iter_state *st = seq->private;
1986 struct net *net = seq_file_net(seq);
1989 ilb = &tcp_hashinfo.listening_hash[st->bucket];
1990 spin_lock_bh(&ilb->lock);
1991 sk = sk_nulls_head(&ilb->head);
1995 ilb = &tcp_hashinfo.listening_hash[st->bucket];
1999 if (st->state == TCP_SEQ_STATE_OPENREQ) {
2000 struct request_sock *req = cur;
2002 icsk = inet_csk(st->syn_wait_sk);
2006 if (req->rsk_ops->family == st->family) {
2012 if (++st->sbucket >= icsk->icsk_accept_queue.listen_opt->nr_table_entries)
2015 req = icsk->icsk_accept_queue.listen_opt->syn_table[st->sbucket];
2017 sk = sk_nulls_next(st->syn_wait_sk);
2018 st->state = TCP_SEQ_STATE_LISTENING;
2019 read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
2021 icsk = inet_csk(sk);
2022 read_lock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
2023 if (reqsk_queue_len(&icsk->icsk_accept_queue))
2025 read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
2026 sk = sk_nulls_next(sk);
2029 sk_nulls_for_each_from(sk, node) {
2030 if (!net_eq(sock_net(sk), net))
2032 if (sk->sk_family == st->family) {
2036 icsk = inet_csk(sk);
2037 read_lock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
2038 if (reqsk_queue_len(&icsk->icsk_accept_queue)) {
2040 st->uid = sock_i_uid(sk);
2041 st->syn_wait_sk = sk;
2042 st->state = TCP_SEQ_STATE_OPENREQ;
2046 read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
2048 spin_unlock_bh(&ilb->lock);
2050 if (++st->bucket < INET_LHTABLE_SIZE) {
2051 ilb = &tcp_hashinfo.listening_hash[st->bucket];
2052 spin_lock_bh(&ilb->lock);
2053 sk = sk_nulls_head(&ilb->head);
2061 static void *listening_get_idx(struct seq_file *seq, loff_t *pos)
2063 struct tcp_iter_state *st = seq->private;
2068 rc = listening_get_next(seq, NULL);
2070 while (rc && *pos) {
2071 rc = listening_get_next(seq, rc);
2077 static inline int empty_bucket(struct tcp_iter_state *st)
2079 return hlist_nulls_empty(&tcp_hashinfo.ehash[st->bucket].chain) &&
2080 hlist_nulls_empty(&tcp_hashinfo.ehash[st->bucket].twchain);
2084 * Get first established socket starting from bucket given in st->bucket.
2085 * If st->bucket is zero, the very first socket in the hash is returned.
2087 static void *established_get_first(struct seq_file *seq)
2089 struct tcp_iter_state *st = seq->private;
2090 struct net *net = seq_file_net(seq);
2094 for (; st->bucket <= tcp_hashinfo.ehash_mask; ++st->bucket) {
2096 struct hlist_nulls_node *node;
2097 struct inet_timewait_sock *tw;
2098 spinlock_t *lock = inet_ehash_lockp(&tcp_hashinfo, st->bucket);
2100 /* Lockless fast path for the common case of empty buckets */
2101 if (empty_bucket(st))
2105 sk_nulls_for_each(sk, node, &tcp_hashinfo.ehash[st->bucket].chain) {
2106 if (sk->sk_family != st->family ||
2107 !net_eq(sock_net(sk), net)) {
2113 st->state = TCP_SEQ_STATE_TIME_WAIT;
2114 inet_twsk_for_each(tw, node,
2115 &tcp_hashinfo.ehash[st->bucket].twchain) {
2116 if (tw->tw_family != st->family ||
2117 !net_eq(twsk_net(tw), net)) {
2123 spin_unlock_bh(lock);
2124 st->state = TCP_SEQ_STATE_ESTABLISHED;
2130 static void *established_get_next(struct seq_file *seq, void *cur)
2132 struct sock *sk = cur;
2133 struct inet_timewait_sock *tw;
2134 struct hlist_nulls_node *node;
2135 struct tcp_iter_state *st = seq->private;
2136 struct net *net = seq_file_net(seq);
2141 if (st->state == TCP_SEQ_STATE_TIME_WAIT) {
2145 while (tw && (tw->tw_family != st->family || !net_eq(twsk_net(tw), net))) {
2152 spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
2153 st->state = TCP_SEQ_STATE_ESTABLISHED;
2155 /* Look for next non empty bucket */
2157 while (++st->bucket <= tcp_hashinfo.ehash_mask &&
2160 if (st->bucket > tcp_hashinfo.ehash_mask)
2163 spin_lock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
2164 sk = sk_nulls_head(&tcp_hashinfo.ehash[st->bucket].chain);
2166 sk = sk_nulls_next(sk);
2168 sk_nulls_for_each_from(sk, node) {
2169 if (sk->sk_family == st->family && net_eq(sock_net(sk), net))
2173 st->state = TCP_SEQ_STATE_TIME_WAIT;
2174 tw = tw_head(&tcp_hashinfo.ehash[st->bucket].twchain);
2182 static void *established_get_idx(struct seq_file *seq, loff_t pos)
2184 struct tcp_iter_state *st = seq->private;
2188 rc = established_get_first(seq);
2191 rc = established_get_next(seq, rc);
2197 static void *tcp_get_idx(struct seq_file *seq, loff_t pos)
2200 struct tcp_iter_state *st = seq->private;
2202 st->state = TCP_SEQ_STATE_LISTENING;
2203 rc = listening_get_idx(seq, &pos);
2206 st->state = TCP_SEQ_STATE_ESTABLISHED;
2207 rc = established_get_idx(seq, pos);
2213 static void *tcp_seek_last_pos(struct seq_file *seq)
2215 struct tcp_iter_state *st = seq->private;
2216 int offset = st->offset;
2217 int orig_num = st->num;
2220 switch (st->state) {
2221 case TCP_SEQ_STATE_OPENREQ:
2222 case TCP_SEQ_STATE_LISTENING:
2223 if (st->bucket >= INET_LHTABLE_SIZE)
2225 st->state = TCP_SEQ_STATE_LISTENING;
2226 rc = listening_get_next(seq, NULL);
2227 while (offset-- && rc)
2228 rc = listening_get_next(seq, rc);
2233 case TCP_SEQ_STATE_ESTABLISHED:
2234 case TCP_SEQ_STATE_TIME_WAIT:
2235 st->state = TCP_SEQ_STATE_ESTABLISHED;
2236 if (st->bucket > tcp_hashinfo.ehash_mask)
2238 rc = established_get_first(seq);
2239 while (offset-- && rc)
2240 rc = established_get_next(seq, rc);
2248 static void *tcp_seq_start(struct seq_file *seq, loff_t *pos)
2250 struct tcp_iter_state *st = seq->private;
2253 if (*pos && *pos == st->last_pos) {
2254 rc = tcp_seek_last_pos(seq);
2259 st->state = TCP_SEQ_STATE_LISTENING;
2263 rc = *pos ? tcp_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
2266 st->last_pos = *pos;
2270 static void *tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2272 struct tcp_iter_state *st = seq->private;
2275 if (v == SEQ_START_TOKEN) {
2276 rc = tcp_get_idx(seq, 0);
2280 switch (st->state) {
2281 case TCP_SEQ_STATE_OPENREQ:
2282 case TCP_SEQ_STATE_LISTENING:
2283 rc = listening_get_next(seq, v);
2285 st->state = TCP_SEQ_STATE_ESTABLISHED;
2288 rc = established_get_first(seq);
2291 case TCP_SEQ_STATE_ESTABLISHED:
2292 case TCP_SEQ_STATE_TIME_WAIT:
2293 rc = established_get_next(seq, v);
2298 st->last_pos = *pos;
2302 static void tcp_seq_stop(struct seq_file *seq, void *v)
2304 struct tcp_iter_state *st = seq->private;
2306 switch (st->state) {
2307 case TCP_SEQ_STATE_OPENREQ:
2309 struct inet_connection_sock *icsk = inet_csk(st->syn_wait_sk);
2310 read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
2312 case TCP_SEQ_STATE_LISTENING:
2313 if (v != SEQ_START_TOKEN)
2314 spin_unlock_bh(&tcp_hashinfo.listening_hash[st->bucket].lock);
2316 case TCP_SEQ_STATE_TIME_WAIT:
2317 case TCP_SEQ_STATE_ESTABLISHED:
2319 spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
2324 static int tcp_seq_open(struct inode *inode, struct file *file)
2326 struct tcp_seq_afinfo *afinfo = PDE(inode)->data;
2327 struct tcp_iter_state *s;
2330 err = seq_open_net(inode, file, &afinfo->seq_ops,
2331 sizeof(struct tcp_iter_state));
2335 s = ((struct seq_file *)file->private_data)->private;
2336 s->family = afinfo->family;
2341 int tcp_proc_register(struct net *net, struct tcp_seq_afinfo *afinfo)
2344 struct proc_dir_entry *p;
2346 afinfo->seq_fops.open = tcp_seq_open;
2347 afinfo->seq_fops.read = seq_read;
2348 afinfo->seq_fops.llseek = seq_lseek;
2349 afinfo->seq_fops.release = seq_release_net;
2351 afinfo->seq_ops.start = tcp_seq_start;
2352 afinfo->seq_ops.next = tcp_seq_next;
2353 afinfo->seq_ops.stop = tcp_seq_stop;
2355 p = proc_create_data(afinfo->name, S_IRUGO, net->proc_net,
2356 &afinfo->seq_fops, afinfo);
2361 EXPORT_SYMBOL(tcp_proc_register);
2363 void tcp_proc_unregister(struct net *net, struct tcp_seq_afinfo *afinfo)
2365 proc_net_remove(net, afinfo->name);
2367 EXPORT_SYMBOL(tcp_proc_unregister);
2369 static void get_openreq4(struct sock *sk, struct request_sock *req,
2370 struct seq_file *f, int i, int uid, int *len)
2372 const struct inet_request_sock *ireq = inet_rsk(req);
2373 int ttd = req->expires - jiffies;
2375 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2376 " %02X %08X:%08X %02X:%08lX %08X %5d %8d %u %d %pK%n",
2379 ntohs(inet_sk(sk)->inet_sport),
2381 ntohs(ireq->rmt_port),
2383 0, 0, /* could print option size, but that is af dependent. */
2384 1, /* timers active (only the expire timer) */
2385 jiffies_to_clock_t(ttd),
2388 0, /* non standard timer */
2389 0, /* open_requests have no inode */
2390 atomic_read(&sk->sk_refcnt),
2395 static void get_tcp4_sock(struct sock *sk, struct seq_file *f, int i, int *len)
2398 unsigned long timer_expires;
2399 struct tcp_sock *tp = tcp_sk(sk);
2400 const struct inet_connection_sock *icsk = inet_csk(sk);
2401 struct inet_sock *inet = inet_sk(sk);
2402 __be32 dest = inet->inet_daddr;
2403 __be32 src = inet->inet_rcv_saddr;
2404 __u16 destp = ntohs(inet->inet_dport);
2405 __u16 srcp = ntohs(inet->inet_sport);
2408 if (icsk->icsk_pending == ICSK_TIME_RETRANS) {
2410 timer_expires = icsk->icsk_timeout;
2411 } else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
2413 timer_expires = icsk->icsk_timeout;
2414 } else if (timer_pending(&sk->sk_timer)) {
2416 timer_expires = sk->sk_timer.expires;
2419 timer_expires = jiffies;
2422 if (sk->sk_state == TCP_LISTEN)
2423 rx_queue = sk->sk_ack_backlog;
2426 * because we dont lock socket, we might find a transient negative value
2428 rx_queue = max_t(int, tp->rcv_nxt - tp->copied_seq, 0);
2430 seq_printf(f, "%4d: %08X:%04X %08X:%04X %02X %08X:%08X %02X:%08lX "
2431 "%08X %5d %8d %lu %d %pK %lu %lu %u %u %d%n",
2432 i, src, srcp, dest, destp, sk->sk_state,
2433 tp->write_seq - tp->snd_una,
2436 jiffies_to_clock_t(timer_expires - jiffies),
2437 icsk->icsk_retransmits,
2439 icsk->icsk_probes_out,
2441 atomic_read(&sk->sk_refcnt), sk,
2442 jiffies_to_clock_t(icsk->icsk_rto),
2443 jiffies_to_clock_t(icsk->icsk_ack.ato),
2444 (icsk->icsk_ack.quick << 1) | icsk->icsk_ack.pingpong,
2446 tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh,
2450 static void get_timewait4_sock(struct inet_timewait_sock *tw,
2451 struct seq_file *f, int i, int *len)
2455 int ttd = tw->tw_ttd - jiffies;
2460 dest = tw->tw_daddr;
2461 src = tw->tw_rcv_saddr;
2462 destp = ntohs(tw->tw_dport);
2463 srcp = ntohs(tw->tw_sport);
2465 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2466 " %02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK%n",
2467 i, src, srcp, dest, destp, tw->tw_substate, 0, 0,
2468 3, jiffies_to_clock_t(ttd), 0, 0, 0, 0,
2469 atomic_read(&tw->tw_refcnt), tw, len);
2474 static int tcp4_seq_show(struct seq_file *seq, void *v)
2476 struct tcp_iter_state *st;
2479 if (v == SEQ_START_TOKEN) {
2480 seq_printf(seq, "%-*s\n", TMPSZ - 1,
2481 " sl local_address rem_address st tx_queue "
2482 "rx_queue tr tm->when retrnsmt uid timeout "
2488 switch (st->state) {
2489 case TCP_SEQ_STATE_LISTENING:
2490 case TCP_SEQ_STATE_ESTABLISHED:
2491 get_tcp4_sock(v, seq, st->num, &len);
2493 case TCP_SEQ_STATE_OPENREQ:
2494 get_openreq4(st->syn_wait_sk, v, seq, st->num, st->uid, &len);
2496 case TCP_SEQ_STATE_TIME_WAIT:
2497 get_timewait4_sock(v, seq, st->num, &len);
2500 seq_printf(seq, "%*s\n", TMPSZ - 1 - len, "");
2505 static struct tcp_seq_afinfo tcp4_seq_afinfo = {
2509 .owner = THIS_MODULE,
2512 .show = tcp4_seq_show,
2516 static int __net_init tcp4_proc_init_net(struct net *net)
2518 return tcp_proc_register(net, &tcp4_seq_afinfo);
2521 static void __net_exit tcp4_proc_exit_net(struct net *net)
2523 tcp_proc_unregister(net, &tcp4_seq_afinfo);
2526 static struct pernet_operations tcp4_net_ops = {
2527 .init = tcp4_proc_init_net,
2528 .exit = tcp4_proc_exit_net,
2531 int __init tcp4_proc_init(void)
2533 return register_pernet_subsys(&tcp4_net_ops);
2536 void tcp4_proc_exit(void)
2538 unregister_pernet_subsys(&tcp4_net_ops);
2540 #endif /* CONFIG_PROC_FS */
2542 struct sk_buff **tcp4_gro_receive(struct sk_buff **head, struct sk_buff *skb)
2544 const struct iphdr *iph = skb_gro_network_header(skb);
2546 switch (skb->ip_summed) {
2547 case CHECKSUM_COMPLETE:
2548 if (!tcp_v4_check(skb_gro_len(skb), iph->saddr, iph->daddr,
2550 skb->ip_summed = CHECKSUM_UNNECESSARY;
2556 NAPI_GRO_CB(skb)->flush = 1;
2560 return tcp_gro_receive(head, skb);
2563 int tcp4_gro_complete(struct sk_buff *skb)
2565 const struct iphdr *iph = ip_hdr(skb);
2566 struct tcphdr *th = tcp_hdr(skb);
2568 th->check = ~tcp_v4_check(skb->len - skb_transport_offset(skb),
2569 iph->saddr, iph->daddr, 0);
2570 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
2572 return tcp_gro_complete(skb);
2575 struct proto tcp_prot = {
2577 .owner = THIS_MODULE,
2579 .connect = tcp_v4_connect,
2580 .disconnect = tcp_disconnect,
2581 .accept = inet_csk_accept,
2583 .init = tcp_v4_init_sock,
2584 .destroy = tcp_v4_destroy_sock,
2585 .shutdown = tcp_shutdown,
2586 .setsockopt = tcp_setsockopt,
2587 .getsockopt = tcp_getsockopt,
2588 .recvmsg = tcp_recvmsg,
2589 .sendmsg = tcp_sendmsg,
2590 .sendpage = tcp_sendpage,
2591 .backlog_rcv = tcp_v4_do_rcv,
2593 .unhash = inet_unhash,
2594 .get_port = inet_csk_get_port,
2595 .enter_memory_pressure = tcp_enter_memory_pressure,
2596 .sockets_allocated = &tcp_sockets_allocated,
2597 .orphan_count = &tcp_orphan_count,
2598 .memory_allocated = &tcp_memory_allocated,
2599 .memory_pressure = &tcp_memory_pressure,
2600 .sysctl_mem = sysctl_tcp_mem,
2601 .sysctl_wmem = sysctl_tcp_wmem,
2602 .sysctl_rmem = sysctl_tcp_rmem,
2603 .max_header = MAX_TCP_HEADER,
2604 .obj_size = sizeof(struct tcp_sock),
2605 .slab_flags = SLAB_DESTROY_BY_RCU,
2606 .twsk_prot = &tcp_timewait_sock_ops,
2607 .rsk_prot = &tcp_request_sock_ops,
2608 .h.hashinfo = &tcp_hashinfo,
2609 .no_autobind = true,
2610 #ifdef CONFIG_COMPAT
2611 .compat_setsockopt = compat_tcp_setsockopt,
2612 .compat_getsockopt = compat_tcp_getsockopt,
2615 EXPORT_SYMBOL(tcp_prot);
2618 static int __net_init tcp_sk_init(struct net *net)
2620 return inet_ctl_sock_create(&net->ipv4.tcp_sock,
2621 PF_INET, SOCK_RAW, IPPROTO_TCP, net);
2624 static void __net_exit tcp_sk_exit(struct net *net)
2626 inet_ctl_sock_destroy(net->ipv4.tcp_sock);
2629 static void __net_exit tcp_sk_exit_batch(struct list_head *net_exit_list)
2631 inet_twsk_purge(&tcp_hashinfo, &tcp_death_row, AF_INET);
2634 static struct pernet_operations __net_initdata tcp_sk_ops = {
2635 .init = tcp_sk_init,
2636 .exit = tcp_sk_exit,
2637 .exit_batch = tcp_sk_exit_batch,
2640 void __init tcp_v4_init(void)
2642 inet_hashinfo_init(&tcp_hashinfo);
2643 if (register_pernet_subsys(&tcp_sk_ops))
2644 panic("Failed to create the TCP control socket.\n");