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.
53 #define pr_fmt(fmt) "TCP: " fmt
55 #include <linux/bottom_half.h>
56 #include <linux/types.h>
57 #include <linux/fcntl.h>
58 #include <linux/module.h>
59 #include <linux/random.h>
60 #include <linux/cache.h>
61 #include <linux/jhash.h>
62 #include <linux/init.h>
63 #include <linux/times.h>
64 #include <linux/slab.h>
66 #include <net/net_namespace.h>
68 #include <net/inet_hashtables.h>
70 #include <net/transp_v6.h>
72 #include <net/inet_common.h>
73 #include <net/timewait_sock.h>
75 #include <net/netdma.h>
76 #include <net/secure_seq.h>
77 #include <net/tcp_memcontrol.h>
79 #include <linux/inet.h>
80 #include <linux/ipv6.h>
81 #include <linux/stddef.h>
82 #include <linux/proc_fs.h>
83 #include <linux/seq_file.h>
85 #include <linux/crypto.h>
86 #include <linux/scatterlist.h>
88 int sysctl_tcp_tw_reuse __read_mostly;
89 int sysctl_tcp_low_latency __read_mostly;
90 EXPORT_SYMBOL(sysctl_tcp_low_latency);
93 #ifdef CONFIG_TCP_MD5SIG
94 static int tcp_v4_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key,
95 __be32 daddr, __be32 saddr, const struct tcphdr *th);
98 struct inet_hashinfo tcp_hashinfo;
99 EXPORT_SYMBOL(tcp_hashinfo);
101 static inline __u32 tcp_v4_init_sequence(const struct sk_buff *skb)
103 return secure_tcp_sequence_number(ip_hdr(skb)->daddr,
106 tcp_hdr(skb)->source);
109 int tcp_twsk_unique(struct sock *sk, struct sock *sktw, void *twp)
111 const struct tcp_timewait_sock *tcptw = tcp_twsk(sktw);
112 struct tcp_sock *tp = tcp_sk(sk);
114 /* With PAWS, it is safe from the viewpoint
115 of data integrity. Even without PAWS it is safe provided sequence
116 spaces do not overlap i.e. at data rates <= 80Mbit/sec.
118 Actually, the idea is close to VJ's one, only timestamp cache is
119 held not per host, but per port pair and TW bucket is used as state
122 If TW bucket has been already destroyed we fall back to VJ's scheme
123 and use initial timestamp retrieved from peer table.
125 if (tcptw->tw_ts_recent_stamp &&
126 (twp == NULL || (sysctl_tcp_tw_reuse &&
127 get_seconds() - tcptw->tw_ts_recent_stamp > 1))) {
128 tp->write_seq = tcptw->tw_snd_nxt + 65535 + 2;
129 if (tp->write_seq == 0)
131 tp->rx_opt.ts_recent = tcptw->tw_ts_recent;
132 tp->rx_opt.ts_recent_stamp = tcptw->tw_ts_recent_stamp;
139 EXPORT_SYMBOL_GPL(tcp_twsk_unique);
141 static int tcp_repair_connect(struct sock *sk)
143 tcp_connect_init(sk);
144 tcp_finish_connect(sk, NULL);
149 /* This will initiate an outgoing connection. */
150 int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
152 struct sockaddr_in *usin = (struct sockaddr_in *)uaddr;
153 struct inet_sock *inet = inet_sk(sk);
154 struct tcp_sock *tp = tcp_sk(sk);
155 __be16 orig_sport, orig_dport;
156 __be32 daddr, nexthop;
160 struct ip_options_rcu *inet_opt;
162 if (addr_len < sizeof(struct sockaddr_in))
165 if (usin->sin_family != AF_INET)
166 return -EAFNOSUPPORT;
168 nexthop = daddr = usin->sin_addr.s_addr;
169 inet_opt = rcu_dereference_protected(inet->inet_opt,
170 sock_owned_by_user(sk));
171 if (inet_opt && inet_opt->opt.srr) {
174 nexthop = inet_opt->opt.faddr;
177 orig_sport = inet->inet_sport;
178 orig_dport = usin->sin_port;
179 fl4 = &inet->cork.fl.u.ip4;
180 rt = ip_route_connect(fl4, nexthop, inet->inet_saddr,
181 RT_CONN_FLAGS(sk), sk->sk_bound_dev_if,
183 orig_sport, orig_dport, sk, true);
186 if (err == -ENETUNREACH)
187 IP_INC_STATS_BH(sock_net(sk), IPSTATS_MIB_OUTNOROUTES);
191 if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) {
196 if (!inet_opt || !inet_opt->opt.srr)
199 if (!inet->inet_saddr)
200 inet->inet_saddr = fl4->saddr;
201 inet->inet_rcv_saddr = inet->inet_saddr;
203 if (tp->rx_opt.ts_recent_stamp && inet->inet_daddr != daddr) {
204 /* Reset inherited state */
205 tp->rx_opt.ts_recent = 0;
206 tp->rx_opt.ts_recent_stamp = 0;
207 if (likely(!tp->repair))
211 if (tcp_death_row.sysctl_tw_recycle &&
212 !tp->rx_opt.ts_recent_stamp && fl4->daddr == daddr) {
213 struct inet_peer *peer = rt_get_peer(rt, fl4->daddr);
215 * VJ's idea. We save last timestamp seen from
216 * the destination in peer table, when entering state
217 * TIME-WAIT * and initialize rx_opt.ts_recent from it,
218 * when trying new connection.
221 inet_peer_refcheck(peer);
222 if ((u32)get_seconds() - peer->tcp_ts_stamp <= TCP_PAWS_MSL) {
223 tp->rx_opt.ts_recent_stamp = peer->tcp_ts_stamp;
224 tp->rx_opt.ts_recent = peer->tcp_ts;
229 inet->inet_dport = usin->sin_port;
230 inet->inet_daddr = daddr;
232 inet_csk(sk)->icsk_ext_hdr_len = 0;
234 inet_csk(sk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
236 tp->rx_opt.mss_clamp = TCP_MSS_DEFAULT;
238 /* Socket identity is still unknown (sport may be zero).
239 * However we set state to SYN-SENT and not releasing socket
240 * lock select source port, enter ourselves into the hash tables and
241 * complete initialization after this.
243 tcp_set_state(sk, TCP_SYN_SENT);
244 err = inet_hash_connect(&tcp_death_row, sk);
248 rt = ip_route_newports(fl4, rt, orig_sport, orig_dport,
249 inet->inet_sport, inet->inet_dport, sk);
255 /* OK, now commit destination to socket. */
256 sk->sk_gso_type = SKB_GSO_TCPV4;
257 sk_setup_caps(sk, &rt->dst);
259 if (!tp->write_seq && likely(!tp->repair))
260 tp->write_seq = secure_tcp_sequence_number(inet->inet_saddr,
265 inet->inet_id = tp->write_seq ^ jiffies;
267 if (likely(!tp->repair))
268 err = tcp_connect(sk);
270 err = tcp_repair_connect(sk);
280 * This unhashes the socket and releases the local port,
283 tcp_set_state(sk, TCP_CLOSE);
285 sk->sk_route_caps = 0;
286 inet->inet_dport = 0;
289 EXPORT_SYMBOL(tcp_v4_connect);
292 * This routine does path mtu discovery as defined in RFC1191.
294 static void do_pmtu_discovery(struct sock *sk, const struct iphdr *iph, u32 mtu)
296 struct dst_entry *dst;
297 struct inet_sock *inet = inet_sk(sk);
299 /* We are not interested in TCP_LISTEN and open_requests (SYN-ACKs
300 * send out by Linux are always <576bytes so they should go through
303 if (sk->sk_state == TCP_LISTEN)
306 /* We don't check in the destentry if pmtu discovery is forbidden
307 * on this route. We just assume that no packet_to_big packets
308 * are send back when pmtu discovery is not active.
309 * There is a small race when the user changes this flag in the
310 * route, but I think that's acceptable.
312 if ((dst = __sk_dst_check(sk, 0)) == NULL)
315 dst->ops->update_pmtu(dst, mtu);
317 /* Something is about to be wrong... Remember soft error
318 * for the case, if this connection will not able to recover.
320 if (mtu < dst_mtu(dst) && ip_dont_fragment(sk, dst))
321 sk->sk_err_soft = EMSGSIZE;
325 if (inet->pmtudisc != IP_PMTUDISC_DONT &&
326 inet_csk(sk)->icsk_pmtu_cookie > mtu) {
327 tcp_sync_mss(sk, mtu);
329 /* Resend the TCP packet because it's
330 * clear that the old packet has been
331 * dropped. This is the new "fast" path mtu
334 tcp_simple_retransmit(sk);
335 } /* else let the usual retransmit timer handle it */
339 * This routine is called by the ICMP module when it gets some
340 * sort of error condition. If err < 0 then the socket should
341 * be closed and the error returned to the user. If err > 0
342 * it's just the icmp type << 8 | icmp code. After adjustment
343 * header points to the first 8 bytes of the tcp header. We need
344 * to find the appropriate port.
346 * The locking strategy used here is very "optimistic". When
347 * someone else accesses the socket the ICMP is just dropped
348 * and for some paths there is no check at all.
349 * A more general error queue to queue errors for later handling
350 * is probably better.
354 void tcp_v4_err(struct sk_buff *icmp_skb, u32 info)
356 const struct iphdr *iph = (const struct iphdr *)icmp_skb->data;
357 struct tcphdr *th = (struct tcphdr *)(icmp_skb->data + (iph->ihl << 2));
358 struct inet_connection_sock *icsk;
360 struct inet_sock *inet;
361 const int type = icmp_hdr(icmp_skb)->type;
362 const int code = icmp_hdr(icmp_skb)->code;
368 struct net *net = dev_net(icmp_skb->dev);
370 if (icmp_skb->len < (iph->ihl << 2) + 8) {
371 ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS);
375 sk = inet_lookup(net, &tcp_hashinfo, iph->daddr, th->dest,
376 iph->saddr, th->source, inet_iif(icmp_skb));
378 ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS);
381 if (sk->sk_state == TCP_TIME_WAIT) {
382 inet_twsk_put(inet_twsk(sk));
387 /* If too many ICMPs get dropped on busy
388 * servers this needs to be solved differently.
390 if (sock_owned_by_user(sk))
391 NET_INC_STATS_BH(net, LINUX_MIB_LOCKDROPPEDICMPS);
393 if (sk->sk_state == TCP_CLOSE)
396 if (unlikely(iph->ttl < inet_sk(sk)->min_ttl)) {
397 NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP);
403 seq = ntohl(th->seq);
404 if (sk->sk_state != TCP_LISTEN &&
405 !between(seq, tp->snd_una, tp->snd_nxt)) {
406 NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
411 case ICMP_SOURCE_QUENCH:
412 /* Just silently ignore these. */
414 case ICMP_PARAMETERPROB:
417 case ICMP_DEST_UNREACH:
418 if (code > NR_ICMP_UNREACH)
421 if (code == ICMP_FRAG_NEEDED) { /* PMTU discovery (RFC1191) */
422 if (!sock_owned_by_user(sk))
423 do_pmtu_discovery(sk, iph, info);
427 err = icmp_err_convert[code].errno;
428 /* check if icmp_skb allows revert of backoff
429 * (see draft-zimmermann-tcp-lcd) */
430 if (code != ICMP_NET_UNREACH && code != ICMP_HOST_UNREACH)
432 if (seq != tp->snd_una || !icsk->icsk_retransmits ||
436 if (sock_owned_by_user(sk))
439 icsk->icsk_backoff--;
440 inet_csk(sk)->icsk_rto = (tp->srtt ? __tcp_set_rto(tp) :
441 TCP_TIMEOUT_INIT) << icsk->icsk_backoff;
444 skb = tcp_write_queue_head(sk);
447 remaining = icsk->icsk_rto - min(icsk->icsk_rto,
448 tcp_time_stamp - TCP_SKB_CB(skb)->when);
451 inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
452 remaining, TCP_RTO_MAX);
454 /* RTO revert clocked out retransmission.
455 * Will retransmit now */
456 tcp_retransmit_timer(sk);
460 case ICMP_TIME_EXCEEDED:
467 switch (sk->sk_state) {
468 struct request_sock *req, **prev;
470 if (sock_owned_by_user(sk))
473 req = inet_csk_search_req(sk, &prev, th->dest,
474 iph->daddr, iph->saddr);
478 /* ICMPs are not backlogged, hence we cannot get
479 an established socket here.
483 if (seq != tcp_rsk(req)->snt_isn) {
484 NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
489 * Still in SYN_RECV, just remove it silently.
490 * There is no good way to pass the error to the newly
491 * created socket, and POSIX does not want network
492 * errors returned from accept().
494 inet_csk_reqsk_queue_drop(sk, req, prev);
498 case TCP_SYN_RECV: /* Cannot happen.
499 It can f.e. if SYNs crossed.
501 if (!sock_owned_by_user(sk)) {
504 sk->sk_error_report(sk);
508 sk->sk_err_soft = err;
513 /* If we've already connected we will keep trying
514 * until we time out, or the user gives up.
516 * rfc1122 4.2.3.9 allows to consider as hard errors
517 * only PROTO_UNREACH and PORT_UNREACH (well, FRAG_FAILED too,
518 * but it is obsoleted by pmtu discovery).
520 * Note, that in modern internet, where routing is unreliable
521 * and in each dark corner broken firewalls sit, sending random
522 * errors ordered by their masters even this two messages finally lose
523 * their original sense (even Linux sends invalid PORT_UNREACHs)
525 * Now we are in compliance with RFCs.
530 if (!sock_owned_by_user(sk) && inet->recverr) {
532 sk->sk_error_report(sk);
533 } else { /* Only an error on timeout */
534 sk->sk_err_soft = err;
542 static void __tcp_v4_send_check(struct sk_buff *skb,
543 __be32 saddr, __be32 daddr)
545 struct tcphdr *th = tcp_hdr(skb);
547 if (skb->ip_summed == CHECKSUM_PARTIAL) {
548 th->check = ~tcp_v4_check(skb->len, saddr, daddr, 0);
549 skb->csum_start = skb_transport_header(skb) - skb->head;
550 skb->csum_offset = offsetof(struct tcphdr, check);
552 th->check = tcp_v4_check(skb->len, saddr, daddr,
559 /* This routine computes an IPv4 TCP checksum. */
560 void tcp_v4_send_check(struct sock *sk, struct sk_buff *skb)
562 const struct inet_sock *inet = inet_sk(sk);
564 __tcp_v4_send_check(skb, inet->inet_saddr, inet->inet_daddr);
566 EXPORT_SYMBOL(tcp_v4_send_check);
568 int tcp_v4_gso_send_check(struct sk_buff *skb)
570 const struct iphdr *iph;
573 if (!pskb_may_pull(skb, sizeof(*th)))
580 skb->ip_summed = CHECKSUM_PARTIAL;
581 __tcp_v4_send_check(skb, iph->saddr, iph->daddr);
586 * This routine will send an RST to the other tcp.
588 * Someone asks: why I NEVER use socket parameters (TOS, TTL etc.)
590 * Answer: if a packet caused RST, it is not for a socket
591 * existing in our system, if it is matched to a socket,
592 * it is just duplicate segment or bug in other side's TCP.
593 * So that we build reply only basing on parameters
594 * arrived with segment.
595 * Exception: precedence violation. We do not implement it in any case.
598 static void tcp_v4_send_reset(struct sock *sk, struct sk_buff *skb)
600 const struct tcphdr *th = tcp_hdr(skb);
603 #ifdef CONFIG_TCP_MD5SIG
604 __be32 opt[(TCPOLEN_MD5SIG_ALIGNED >> 2)];
607 struct ip_reply_arg arg;
608 #ifdef CONFIG_TCP_MD5SIG
609 struct tcp_md5sig_key *key;
610 const __u8 *hash_location = NULL;
611 unsigned char newhash[16];
613 struct sock *sk1 = NULL;
617 /* Never send a reset in response to a reset. */
621 if (skb_rtable(skb)->rt_type != RTN_LOCAL)
624 /* Swap the send and the receive. */
625 memset(&rep, 0, sizeof(rep));
626 rep.th.dest = th->source;
627 rep.th.source = th->dest;
628 rep.th.doff = sizeof(struct tcphdr) / 4;
632 rep.th.seq = th->ack_seq;
635 rep.th.ack_seq = htonl(ntohl(th->seq) + th->syn + th->fin +
636 skb->len - (th->doff << 2));
639 memset(&arg, 0, sizeof(arg));
640 arg.iov[0].iov_base = (unsigned char *)&rep;
641 arg.iov[0].iov_len = sizeof(rep.th);
643 #ifdef CONFIG_TCP_MD5SIG
644 hash_location = tcp_parse_md5sig_option(th);
645 if (!sk && hash_location) {
647 * active side is lost. Try to find listening socket through
648 * source port, and then find md5 key through listening socket.
649 * we are not loose security here:
650 * Incoming packet is checked with md5 hash with finding key,
651 * no RST generated if md5 hash doesn't match.
653 sk1 = __inet_lookup_listener(dev_net(skb_dst(skb)->dev),
654 &tcp_hashinfo, ip_hdr(skb)->daddr,
655 ntohs(th->source), inet_iif(skb));
656 /* don't send rst if it can't find key */
660 key = tcp_md5_do_lookup(sk1, (union tcp_md5_addr *)
661 &ip_hdr(skb)->saddr, AF_INET);
665 genhash = tcp_v4_md5_hash_skb(newhash, key, NULL, NULL, skb);
666 if (genhash || memcmp(hash_location, newhash, 16) != 0)
669 key = sk ? tcp_md5_do_lookup(sk, (union tcp_md5_addr *)
675 rep.opt[0] = htonl((TCPOPT_NOP << 24) |
677 (TCPOPT_MD5SIG << 8) |
679 /* Update length and the length the header thinks exists */
680 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED;
681 rep.th.doff = arg.iov[0].iov_len / 4;
683 tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[1],
684 key, ip_hdr(skb)->saddr,
685 ip_hdr(skb)->daddr, &rep.th);
688 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
689 ip_hdr(skb)->saddr, /* XXX */
690 arg.iov[0].iov_len, IPPROTO_TCP, 0);
691 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
692 arg.flags = (sk && inet_sk(sk)->transparent) ? IP_REPLY_ARG_NOSRCCHECK : 0;
693 /* When socket is gone, all binding information is lost.
694 * routing might fail in this case. using iif for oif to
695 * make sure we can deliver it
697 arg.bound_dev_if = sk ? sk->sk_bound_dev_if : inet_iif(skb);
699 net = dev_net(skb_dst(skb)->dev);
700 arg.tos = ip_hdr(skb)->tos;
701 ip_send_reply(net->ipv4.tcp_sock, skb, ip_hdr(skb)->saddr,
702 &arg, arg.iov[0].iov_len);
704 TCP_INC_STATS_BH(net, TCP_MIB_OUTSEGS);
705 TCP_INC_STATS_BH(net, TCP_MIB_OUTRSTS);
707 #ifdef CONFIG_TCP_MD5SIG
716 /* The code following below sending ACKs in SYN-RECV and TIME-WAIT states
717 outside socket context is ugly, certainly. What can I do?
720 static void tcp_v4_send_ack(struct sk_buff *skb, u32 seq, u32 ack,
721 u32 win, u32 ts, int oif,
722 struct tcp_md5sig_key *key,
723 int reply_flags, u8 tos)
725 const struct tcphdr *th = tcp_hdr(skb);
728 __be32 opt[(TCPOLEN_TSTAMP_ALIGNED >> 2)
729 #ifdef CONFIG_TCP_MD5SIG
730 + (TCPOLEN_MD5SIG_ALIGNED >> 2)
734 struct ip_reply_arg arg;
735 struct net *net = dev_net(skb_dst(skb)->dev);
737 memset(&rep.th, 0, sizeof(struct tcphdr));
738 memset(&arg, 0, sizeof(arg));
740 arg.iov[0].iov_base = (unsigned char *)&rep;
741 arg.iov[0].iov_len = sizeof(rep.th);
743 rep.opt[0] = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
744 (TCPOPT_TIMESTAMP << 8) |
746 rep.opt[1] = htonl(tcp_time_stamp);
747 rep.opt[2] = htonl(ts);
748 arg.iov[0].iov_len += TCPOLEN_TSTAMP_ALIGNED;
751 /* Swap the send and the receive. */
752 rep.th.dest = th->source;
753 rep.th.source = th->dest;
754 rep.th.doff = arg.iov[0].iov_len / 4;
755 rep.th.seq = htonl(seq);
756 rep.th.ack_seq = htonl(ack);
758 rep.th.window = htons(win);
760 #ifdef CONFIG_TCP_MD5SIG
762 int offset = (ts) ? 3 : 0;
764 rep.opt[offset++] = htonl((TCPOPT_NOP << 24) |
766 (TCPOPT_MD5SIG << 8) |
768 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED;
769 rep.th.doff = arg.iov[0].iov_len/4;
771 tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[offset],
772 key, ip_hdr(skb)->saddr,
773 ip_hdr(skb)->daddr, &rep.th);
776 arg.flags = reply_flags;
777 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
778 ip_hdr(skb)->saddr, /* XXX */
779 arg.iov[0].iov_len, IPPROTO_TCP, 0);
780 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
782 arg.bound_dev_if = oif;
784 ip_send_reply(net->ipv4.tcp_sock, skb, ip_hdr(skb)->saddr,
785 &arg, arg.iov[0].iov_len);
787 TCP_INC_STATS_BH(net, TCP_MIB_OUTSEGS);
790 static void tcp_v4_timewait_ack(struct sock *sk, struct sk_buff *skb)
792 struct inet_timewait_sock *tw = inet_twsk(sk);
793 struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
795 tcp_v4_send_ack(skb, tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
796 tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
799 tcp_twsk_md5_key(tcptw),
800 tw->tw_transparent ? IP_REPLY_ARG_NOSRCCHECK : 0,
807 static void tcp_v4_reqsk_send_ack(struct sock *sk, struct sk_buff *skb,
808 struct request_sock *req)
810 tcp_v4_send_ack(skb, tcp_rsk(req)->snt_isn + 1,
811 tcp_rsk(req)->rcv_isn + 1, req->rcv_wnd,
814 tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&ip_hdr(skb)->daddr,
816 inet_rsk(req)->no_srccheck ? IP_REPLY_ARG_NOSRCCHECK : 0,
821 * Send a SYN-ACK after having received a SYN.
822 * This still operates on a request_sock only, not on a big
825 static int tcp_v4_send_synack(struct sock *sk, struct dst_entry *dst,
826 struct request_sock *req,
827 struct request_values *rvp,
830 const struct inet_request_sock *ireq = inet_rsk(req);
833 struct sk_buff * skb;
835 /* First, grab a route. */
836 if (!dst && (dst = inet_csk_route_req(sk, &fl4, req)) == NULL)
839 skb = tcp_make_synack(sk, dst, req, rvp);
842 __tcp_v4_send_check(skb, ireq->loc_addr, ireq->rmt_addr);
844 skb_set_queue_mapping(skb, queue_mapping);
845 err = ip_build_and_send_pkt(skb, sk, ireq->loc_addr,
848 err = net_xmit_eval(err);
855 static int tcp_v4_rtx_synack(struct sock *sk, struct request_sock *req,
856 struct request_values *rvp)
858 TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_RETRANSSEGS);
859 return tcp_v4_send_synack(sk, NULL, req, rvp, 0);
863 * IPv4 request_sock destructor.
865 static void tcp_v4_reqsk_destructor(struct request_sock *req)
867 kfree(inet_rsk(req)->opt);
871 * Return true if a syncookie should be sent
873 bool tcp_syn_flood_action(struct sock *sk,
874 const struct sk_buff *skb,
877 const char *msg = "Dropping request";
878 bool want_cookie = false;
879 struct listen_sock *lopt;
883 #ifdef CONFIG_SYN_COOKIES
884 if (sysctl_tcp_syncookies) {
885 msg = "Sending cookies";
887 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPREQQFULLDOCOOKIES);
890 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPREQQFULLDROP);
892 lopt = inet_csk(sk)->icsk_accept_queue.listen_opt;
893 if (!lopt->synflood_warned) {
894 lopt->synflood_warned = 1;
895 pr_info("%s: Possible SYN flooding on port %d. %s. Check SNMP counters.\n",
896 proto, ntohs(tcp_hdr(skb)->dest), msg);
900 EXPORT_SYMBOL(tcp_syn_flood_action);
903 * Save and compile IPv4 options into the request_sock if needed.
905 static struct ip_options_rcu *tcp_v4_save_options(struct sock *sk,
908 const struct ip_options *opt = &(IPCB(skb)->opt);
909 struct ip_options_rcu *dopt = NULL;
911 if (opt && opt->optlen) {
912 int opt_size = sizeof(*dopt) + opt->optlen;
914 dopt = kmalloc(opt_size, GFP_ATOMIC);
916 if (ip_options_echo(&dopt->opt, skb)) {
925 #ifdef CONFIG_TCP_MD5SIG
927 * RFC2385 MD5 checksumming requires a mapping of
928 * IP address->MD5 Key.
929 * We need to maintain these in the sk structure.
932 /* Find the Key structure for an address. */
933 struct tcp_md5sig_key *tcp_md5_do_lookup(struct sock *sk,
934 const union tcp_md5_addr *addr,
937 struct tcp_sock *tp = tcp_sk(sk);
938 struct tcp_md5sig_key *key;
939 struct hlist_node *pos;
940 unsigned int size = sizeof(struct in_addr);
941 struct tcp_md5sig_info *md5sig;
943 /* caller either holds rcu_read_lock() or socket lock */
944 md5sig = rcu_dereference_check(tp->md5sig_info,
945 sock_owned_by_user(sk) ||
946 lockdep_is_held(&sk->sk_lock.slock));
949 #if IS_ENABLED(CONFIG_IPV6)
950 if (family == AF_INET6)
951 size = sizeof(struct in6_addr);
953 hlist_for_each_entry_rcu(key, pos, &md5sig->head, node) {
954 if (key->family != family)
956 if (!memcmp(&key->addr, addr, size))
961 EXPORT_SYMBOL(tcp_md5_do_lookup);
963 struct tcp_md5sig_key *tcp_v4_md5_lookup(struct sock *sk,
964 struct sock *addr_sk)
966 union tcp_md5_addr *addr;
968 addr = (union tcp_md5_addr *)&inet_sk(addr_sk)->inet_daddr;
969 return tcp_md5_do_lookup(sk, addr, AF_INET);
971 EXPORT_SYMBOL(tcp_v4_md5_lookup);
973 static struct tcp_md5sig_key *tcp_v4_reqsk_md5_lookup(struct sock *sk,
974 struct request_sock *req)
976 union tcp_md5_addr *addr;
978 addr = (union tcp_md5_addr *)&inet_rsk(req)->rmt_addr;
979 return tcp_md5_do_lookup(sk, addr, AF_INET);
982 /* This can be called on a newly created socket, from other files */
983 int tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr,
984 int family, const u8 *newkey, u8 newkeylen, gfp_t gfp)
986 /* Add Key to the list */
987 struct tcp_md5sig_key *key;
988 struct tcp_sock *tp = tcp_sk(sk);
989 struct tcp_md5sig_info *md5sig;
991 key = tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&addr, AF_INET);
993 /* Pre-existing entry - just update that one. */
994 memcpy(key->key, newkey, newkeylen);
995 key->keylen = newkeylen;
999 md5sig = rcu_dereference_protected(tp->md5sig_info,
1000 sock_owned_by_user(sk));
1002 md5sig = kmalloc(sizeof(*md5sig), gfp);
1006 sk_nocaps_add(sk, NETIF_F_GSO_MASK);
1007 INIT_HLIST_HEAD(&md5sig->head);
1008 rcu_assign_pointer(tp->md5sig_info, md5sig);
1011 key = sock_kmalloc(sk, sizeof(*key), gfp);
1014 if (hlist_empty(&md5sig->head) && !tcp_alloc_md5sig_pool(sk)) {
1015 sock_kfree_s(sk, key, sizeof(*key));
1019 memcpy(key->key, newkey, newkeylen);
1020 key->keylen = newkeylen;
1021 key->family = family;
1022 memcpy(&key->addr, addr,
1023 (family == AF_INET6) ? sizeof(struct in6_addr) :
1024 sizeof(struct in_addr));
1025 hlist_add_head_rcu(&key->node, &md5sig->head);
1028 EXPORT_SYMBOL(tcp_md5_do_add);
1030 int tcp_md5_do_del(struct sock *sk, const union tcp_md5_addr *addr, int family)
1032 struct tcp_sock *tp = tcp_sk(sk);
1033 struct tcp_md5sig_key *key;
1034 struct tcp_md5sig_info *md5sig;
1036 key = tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&addr, AF_INET);
1039 hlist_del_rcu(&key->node);
1040 atomic_sub(sizeof(*key), &sk->sk_omem_alloc);
1041 kfree_rcu(key, rcu);
1042 md5sig = rcu_dereference_protected(tp->md5sig_info,
1043 sock_owned_by_user(sk));
1044 if (hlist_empty(&md5sig->head))
1045 tcp_free_md5sig_pool();
1048 EXPORT_SYMBOL(tcp_md5_do_del);
1050 void tcp_clear_md5_list(struct sock *sk)
1052 struct tcp_sock *tp = tcp_sk(sk);
1053 struct tcp_md5sig_key *key;
1054 struct hlist_node *pos, *n;
1055 struct tcp_md5sig_info *md5sig;
1057 md5sig = rcu_dereference_protected(tp->md5sig_info, 1);
1059 if (!hlist_empty(&md5sig->head))
1060 tcp_free_md5sig_pool();
1061 hlist_for_each_entry_safe(key, pos, n, &md5sig->head, node) {
1062 hlist_del_rcu(&key->node);
1063 atomic_sub(sizeof(*key), &sk->sk_omem_alloc);
1064 kfree_rcu(key, rcu);
1068 static int tcp_v4_parse_md5_keys(struct sock *sk, char __user *optval,
1071 struct tcp_md5sig cmd;
1072 struct sockaddr_in *sin = (struct sockaddr_in *)&cmd.tcpm_addr;
1074 if (optlen < sizeof(cmd))
1077 if (copy_from_user(&cmd, optval, sizeof(cmd)))
1080 if (sin->sin_family != AF_INET)
1083 if (!cmd.tcpm_key || !cmd.tcpm_keylen)
1084 return tcp_md5_do_del(sk, (union tcp_md5_addr *)&sin->sin_addr.s_addr,
1087 if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN)
1090 return tcp_md5_do_add(sk, (union tcp_md5_addr *)&sin->sin_addr.s_addr,
1091 AF_INET, cmd.tcpm_key, cmd.tcpm_keylen,
1095 static int tcp_v4_md5_hash_pseudoheader(struct tcp_md5sig_pool *hp,
1096 __be32 daddr, __be32 saddr, int nbytes)
1098 struct tcp4_pseudohdr *bp;
1099 struct scatterlist sg;
1101 bp = &hp->md5_blk.ip4;
1104 * 1. the TCP pseudo-header (in the order: source IP address,
1105 * destination IP address, zero-padded protocol number, and
1111 bp->protocol = IPPROTO_TCP;
1112 bp->len = cpu_to_be16(nbytes);
1114 sg_init_one(&sg, bp, sizeof(*bp));
1115 return crypto_hash_update(&hp->md5_desc, &sg, sizeof(*bp));
1118 static int tcp_v4_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key,
1119 __be32 daddr, __be32 saddr, const struct tcphdr *th)
1121 struct tcp_md5sig_pool *hp;
1122 struct hash_desc *desc;
1124 hp = tcp_get_md5sig_pool();
1126 goto clear_hash_noput;
1127 desc = &hp->md5_desc;
1129 if (crypto_hash_init(desc))
1131 if (tcp_v4_md5_hash_pseudoheader(hp, daddr, saddr, th->doff << 2))
1133 if (tcp_md5_hash_header(hp, th))
1135 if (tcp_md5_hash_key(hp, key))
1137 if (crypto_hash_final(desc, md5_hash))
1140 tcp_put_md5sig_pool();
1144 tcp_put_md5sig_pool();
1146 memset(md5_hash, 0, 16);
1150 int tcp_v4_md5_hash_skb(char *md5_hash, struct tcp_md5sig_key *key,
1151 const struct sock *sk, const struct request_sock *req,
1152 const struct sk_buff *skb)
1154 struct tcp_md5sig_pool *hp;
1155 struct hash_desc *desc;
1156 const struct tcphdr *th = tcp_hdr(skb);
1157 __be32 saddr, daddr;
1160 saddr = inet_sk(sk)->inet_saddr;
1161 daddr = inet_sk(sk)->inet_daddr;
1163 saddr = inet_rsk(req)->loc_addr;
1164 daddr = inet_rsk(req)->rmt_addr;
1166 const struct iphdr *iph = ip_hdr(skb);
1171 hp = tcp_get_md5sig_pool();
1173 goto clear_hash_noput;
1174 desc = &hp->md5_desc;
1176 if (crypto_hash_init(desc))
1179 if (tcp_v4_md5_hash_pseudoheader(hp, daddr, saddr, skb->len))
1181 if (tcp_md5_hash_header(hp, th))
1183 if (tcp_md5_hash_skb_data(hp, skb, th->doff << 2))
1185 if (tcp_md5_hash_key(hp, key))
1187 if (crypto_hash_final(desc, md5_hash))
1190 tcp_put_md5sig_pool();
1194 tcp_put_md5sig_pool();
1196 memset(md5_hash, 0, 16);
1199 EXPORT_SYMBOL(tcp_v4_md5_hash_skb);
1201 static bool tcp_v4_inbound_md5_hash(struct sock *sk, const struct sk_buff *skb)
1204 * This gets called for each TCP segment that arrives
1205 * so we want to be efficient.
1206 * We have 3 drop cases:
1207 * o No MD5 hash and one expected.
1208 * o MD5 hash and we're not expecting one.
1209 * o MD5 hash and its wrong.
1211 const __u8 *hash_location = NULL;
1212 struct tcp_md5sig_key *hash_expected;
1213 const struct iphdr *iph = ip_hdr(skb);
1214 const struct tcphdr *th = tcp_hdr(skb);
1216 unsigned char newhash[16];
1218 hash_expected = tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&iph->saddr,
1220 hash_location = tcp_parse_md5sig_option(th);
1222 /* We've parsed the options - do we have a hash? */
1223 if (!hash_expected && !hash_location)
1226 if (hash_expected && !hash_location) {
1227 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5NOTFOUND);
1231 if (!hash_expected && hash_location) {
1232 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5UNEXPECTED);
1236 /* Okay, so this is hash_expected and hash_location -
1237 * so we need to calculate the checksum.
1239 genhash = tcp_v4_md5_hash_skb(newhash,
1243 if (genhash || memcmp(hash_location, newhash, 16) != 0) {
1244 net_info_ratelimited("MD5 Hash failed for (%pI4, %d)->(%pI4, %d)%s\n",
1245 &iph->saddr, ntohs(th->source),
1246 &iph->daddr, ntohs(th->dest),
1247 genhash ? " tcp_v4_calc_md5_hash failed"
1256 struct request_sock_ops tcp_request_sock_ops __read_mostly = {
1258 .obj_size = sizeof(struct tcp_request_sock),
1259 .rtx_syn_ack = tcp_v4_rtx_synack,
1260 .send_ack = tcp_v4_reqsk_send_ack,
1261 .destructor = tcp_v4_reqsk_destructor,
1262 .send_reset = tcp_v4_send_reset,
1263 .syn_ack_timeout = tcp_syn_ack_timeout,
1266 #ifdef CONFIG_TCP_MD5SIG
1267 static const struct tcp_request_sock_ops tcp_request_sock_ipv4_ops = {
1268 .md5_lookup = tcp_v4_reqsk_md5_lookup,
1269 .calc_md5_hash = tcp_v4_md5_hash_skb,
1273 int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
1275 struct tcp_extend_values tmp_ext;
1276 struct tcp_options_received tmp_opt;
1277 const u8 *hash_location;
1278 struct request_sock *req;
1279 struct inet_request_sock *ireq;
1280 struct tcp_sock *tp = tcp_sk(sk);
1281 struct dst_entry *dst = NULL;
1282 __be32 saddr = ip_hdr(skb)->saddr;
1283 __be32 daddr = ip_hdr(skb)->daddr;
1284 __u32 isn = TCP_SKB_CB(skb)->when;
1285 bool want_cookie = false;
1287 /* Never answer to SYNs send to broadcast or multicast */
1288 if (skb_rtable(skb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
1291 /* TW buckets are converted to open requests without
1292 * limitations, they conserve resources and peer is
1293 * evidently real one.
1295 if (inet_csk_reqsk_queue_is_full(sk) && !isn) {
1296 want_cookie = tcp_syn_flood_action(sk, skb, "TCP");
1301 /* Accept backlog is full. If we have already queued enough
1302 * of warm entries in syn queue, drop request. It is better than
1303 * clogging syn queue with openreqs with exponentially increasing
1306 if (sk_acceptq_is_full(sk) && inet_csk_reqsk_queue_young(sk) > 1)
1309 req = inet_reqsk_alloc(&tcp_request_sock_ops);
1313 #ifdef CONFIG_TCP_MD5SIG
1314 tcp_rsk(req)->af_specific = &tcp_request_sock_ipv4_ops;
1317 tcp_clear_options(&tmp_opt);
1318 tmp_opt.mss_clamp = TCP_MSS_DEFAULT;
1319 tmp_opt.user_mss = tp->rx_opt.user_mss;
1320 tcp_parse_options(skb, &tmp_opt, &hash_location, 0);
1322 if (tmp_opt.cookie_plus > 0 &&
1323 tmp_opt.saw_tstamp &&
1324 !tp->rx_opt.cookie_out_never &&
1325 (sysctl_tcp_cookie_size > 0 ||
1326 (tp->cookie_values != NULL &&
1327 tp->cookie_values->cookie_desired > 0))) {
1329 u32 *mess = &tmp_ext.cookie_bakery[COOKIE_DIGEST_WORDS];
1330 int l = tmp_opt.cookie_plus - TCPOLEN_COOKIE_BASE;
1332 if (tcp_cookie_generator(&tmp_ext.cookie_bakery[0]) != 0)
1333 goto drop_and_release;
1335 /* Secret recipe starts with IP addresses */
1336 *mess++ ^= (__force u32)daddr;
1337 *mess++ ^= (__force u32)saddr;
1339 /* plus variable length Initiator Cookie */
1342 *c++ ^= *hash_location++;
1344 want_cookie = false; /* not our kind of cookie */
1345 tmp_ext.cookie_out_never = 0; /* false */
1346 tmp_ext.cookie_plus = tmp_opt.cookie_plus;
1347 } else if (!tp->rx_opt.cookie_in_always) {
1348 /* redundant indications, but ensure initialization. */
1349 tmp_ext.cookie_out_never = 1; /* true */
1350 tmp_ext.cookie_plus = 0;
1352 goto drop_and_release;
1354 tmp_ext.cookie_in_always = tp->rx_opt.cookie_in_always;
1356 if (want_cookie && !tmp_opt.saw_tstamp)
1357 tcp_clear_options(&tmp_opt);
1359 tmp_opt.tstamp_ok = tmp_opt.saw_tstamp;
1360 tcp_openreq_init(req, &tmp_opt, skb);
1362 ireq = inet_rsk(req);
1363 ireq->loc_addr = daddr;
1364 ireq->rmt_addr = saddr;
1365 ireq->no_srccheck = inet_sk(sk)->transparent;
1366 ireq->opt = tcp_v4_save_options(sk, skb);
1368 if (security_inet_conn_request(sk, skb, req))
1371 if (!want_cookie || tmp_opt.tstamp_ok)
1372 TCP_ECN_create_request(req, skb);
1375 isn = cookie_v4_init_sequence(sk, skb, &req->mss);
1376 req->cookie_ts = tmp_opt.tstamp_ok;
1378 struct inet_peer *peer = NULL;
1381 /* VJ's idea. We save last timestamp seen
1382 * from the destination in peer table, when entering
1383 * state TIME-WAIT, and check against it before
1384 * accepting new connection request.
1386 * If "isn" is not zero, this request hit alive
1387 * timewait bucket, so that all the necessary checks
1388 * are made in the function processing timewait state.
1390 if (tmp_opt.saw_tstamp &&
1391 tcp_death_row.sysctl_tw_recycle &&
1392 (dst = inet_csk_route_req(sk, &fl4, req)) != NULL &&
1393 fl4.daddr == saddr &&
1394 (peer = rt_get_peer((struct rtable *)dst, fl4.daddr)) != NULL) {
1395 inet_peer_refcheck(peer);
1396 if ((u32)get_seconds() - peer->tcp_ts_stamp < TCP_PAWS_MSL &&
1397 (s32)(peer->tcp_ts - req->ts_recent) >
1399 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_PAWSPASSIVEREJECTED);
1400 goto drop_and_release;
1403 /* Kill the following clause, if you dislike this way. */
1404 else if (!sysctl_tcp_syncookies &&
1405 (sysctl_max_syn_backlog - inet_csk_reqsk_queue_len(sk) <
1406 (sysctl_max_syn_backlog >> 2)) &&
1407 (!peer || !peer->tcp_ts_stamp) &&
1408 (!dst || !dst_metric(dst, RTAX_RTT))) {
1409 /* Without syncookies last quarter of
1410 * backlog is filled with destinations,
1411 * proven to be alive.
1412 * It means that we continue to communicate
1413 * to destinations, already remembered
1414 * to the moment of synflood.
1416 LIMIT_NETDEBUG(KERN_DEBUG pr_fmt("drop open request from %pI4/%u\n"),
1417 &saddr, ntohs(tcp_hdr(skb)->source));
1418 goto drop_and_release;
1421 isn = tcp_v4_init_sequence(skb);
1423 tcp_rsk(req)->snt_isn = isn;
1424 tcp_rsk(req)->snt_synack = tcp_time_stamp;
1426 if (tcp_v4_send_synack(sk, dst, req,
1427 (struct request_values *)&tmp_ext,
1428 skb_get_queue_mapping(skb)) ||
1432 inet_csk_reqsk_queue_hash_add(sk, req, TCP_TIMEOUT_INIT);
1442 EXPORT_SYMBOL(tcp_v4_conn_request);
1446 * The three way handshake has completed - we got a valid synack -
1447 * now create the new socket.
1449 struct sock *tcp_v4_syn_recv_sock(struct sock *sk, struct sk_buff *skb,
1450 struct request_sock *req,
1451 struct dst_entry *dst)
1453 struct inet_request_sock *ireq;
1454 struct inet_sock *newinet;
1455 struct tcp_sock *newtp;
1457 #ifdef CONFIG_TCP_MD5SIG
1458 struct tcp_md5sig_key *key;
1460 struct ip_options_rcu *inet_opt;
1462 if (sk_acceptq_is_full(sk))
1465 newsk = tcp_create_openreq_child(sk, req, skb);
1469 newsk->sk_gso_type = SKB_GSO_TCPV4;
1471 newtp = tcp_sk(newsk);
1472 newinet = inet_sk(newsk);
1473 ireq = inet_rsk(req);
1474 newinet->inet_daddr = ireq->rmt_addr;
1475 newinet->inet_rcv_saddr = ireq->loc_addr;
1476 newinet->inet_saddr = ireq->loc_addr;
1477 inet_opt = ireq->opt;
1478 rcu_assign_pointer(newinet->inet_opt, inet_opt);
1480 newinet->mc_index = inet_iif(skb);
1481 newinet->mc_ttl = ip_hdr(skb)->ttl;
1482 newinet->rcv_tos = ip_hdr(skb)->tos;
1483 inet_csk(newsk)->icsk_ext_hdr_len = 0;
1485 inet_csk(newsk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
1486 newinet->inet_id = newtp->write_seq ^ jiffies;
1489 dst = inet_csk_route_child_sock(sk, newsk, req);
1493 /* syncookie case : see end of cookie_v4_check() */
1495 sk_setup_caps(newsk, dst);
1497 tcp_mtup_init(newsk);
1498 tcp_sync_mss(newsk, dst_mtu(dst));
1499 newtp->advmss = dst_metric_advmss(dst);
1500 if (tcp_sk(sk)->rx_opt.user_mss &&
1501 tcp_sk(sk)->rx_opt.user_mss < newtp->advmss)
1502 newtp->advmss = tcp_sk(sk)->rx_opt.user_mss;
1504 tcp_initialize_rcv_mss(newsk);
1505 if (tcp_rsk(req)->snt_synack)
1506 tcp_valid_rtt_meas(newsk,
1507 tcp_time_stamp - tcp_rsk(req)->snt_synack);
1508 newtp->total_retrans = req->retrans;
1510 #ifdef CONFIG_TCP_MD5SIG
1511 /* Copy over the MD5 key from the original socket */
1512 key = tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&newinet->inet_daddr,
1516 * We're using one, so create a matching key
1517 * on the newsk structure. If we fail to get
1518 * memory, then we end up not copying the key
1521 tcp_md5_do_add(newsk, (union tcp_md5_addr *)&newinet->inet_daddr,
1522 AF_INET, key->key, key->keylen, GFP_ATOMIC);
1523 sk_nocaps_add(newsk, NETIF_F_GSO_MASK);
1527 if (__inet_inherit_port(sk, newsk) < 0)
1529 __inet_hash_nolisten(newsk, NULL);
1534 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
1538 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
1541 tcp_clear_xmit_timers(newsk);
1542 tcp_cleanup_congestion_control(newsk);
1543 bh_unlock_sock(newsk);
1547 EXPORT_SYMBOL(tcp_v4_syn_recv_sock);
1549 static struct sock *tcp_v4_hnd_req(struct sock *sk, struct sk_buff *skb)
1551 struct tcphdr *th = tcp_hdr(skb);
1552 const struct iphdr *iph = ip_hdr(skb);
1554 struct request_sock **prev;
1555 /* Find possible connection requests. */
1556 struct request_sock *req = inet_csk_search_req(sk, &prev, th->source,
1557 iph->saddr, iph->daddr);
1559 return tcp_check_req(sk, skb, req, prev);
1561 nsk = inet_lookup_established(sock_net(sk), &tcp_hashinfo, iph->saddr,
1562 th->source, iph->daddr, th->dest, inet_iif(skb));
1565 if (nsk->sk_state != TCP_TIME_WAIT) {
1569 inet_twsk_put(inet_twsk(nsk));
1573 #ifdef CONFIG_SYN_COOKIES
1575 sk = cookie_v4_check(sk, skb, &(IPCB(skb)->opt));
1580 static __sum16 tcp_v4_checksum_init(struct sk_buff *skb)
1582 const struct iphdr *iph = ip_hdr(skb);
1584 if (skb->ip_summed == CHECKSUM_COMPLETE) {
1585 if (!tcp_v4_check(skb->len, iph->saddr,
1586 iph->daddr, skb->csum)) {
1587 skb->ip_summed = CHECKSUM_UNNECESSARY;
1592 skb->csum = csum_tcpudp_nofold(iph->saddr, iph->daddr,
1593 skb->len, IPPROTO_TCP, 0);
1595 if (skb->len <= 76) {
1596 return __skb_checksum_complete(skb);
1602 /* The socket must have it's spinlock held when we get
1605 * We have a potential double-lock case here, so even when
1606 * doing backlog processing we use the BH locking scheme.
1607 * This is because we cannot sleep with the original spinlock
1610 int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
1613 #ifdef CONFIG_TCP_MD5SIG
1615 * We really want to reject the packet as early as possible
1617 * o We're expecting an MD5'd packet and this is no MD5 tcp option
1618 * o There is an MD5 option and we're not expecting one
1620 if (tcp_v4_inbound_md5_hash(sk, skb))
1624 if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
1625 sock_rps_save_rxhash(sk, skb);
1626 if (tcp_rcv_established(sk, skb, tcp_hdr(skb), skb->len)) {
1633 if (skb->len < tcp_hdrlen(skb) || tcp_checksum_complete(skb))
1636 if (sk->sk_state == TCP_LISTEN) {
1637 struct sock *nsk = tcp_v4_hnd_req(sk, skb);
1642 sock_rps_save_rxhash(nsk, skb);
1643 if (tcp_child_process(sk, nsk, skb)) {
1650 sock_rps_save_rxhash(sk, skb);
1652 if (tcp_rcv_state_process(sk, skb, tcp_hdr(skb), skb->len)) {
1659 tcp_v4_send_reset(rsk, skb);
1662 /* Be careful here. If this function gets more complicated and
1663 * gcc suffers from register pressure on the x86, sk (in %ebx)
1664 * might be destroyed here. This current version compiles correctly,
1665 * but you have been warned.
1670 TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_INERRS);
1673 EXPORT_SYMBOL(tcp_v4_do_rcv);
1679 int tcp_v4_rcv(struct sk_buff *skb)
1681 const struct iphdr *iph;
1682 const struct tcphdr *th;
1685 struct net *net = dev_net(skb->dev);
1687 if (skb->pkt_type != PACKET_HOST)
1690 /* Count it even if it's bad */
1691 TCP_INC_STATS_BH(net, TCP_MIB_INSEGS);
1693 if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
1698 if (th->doff < sizeof(struct tcphdr) / 4)
1700 if (!pskb_may_pull(skb, th->doff * 4))
1703 /* An explanation is required here, I think.
1704 * Packet length and doff are validated by header prediction,
1705 * provided case of th->doff==0 is eliminated.
1706 * So, we defer the checks. */
1707 if (!skb_csum_unnecessary(skb) && tcp_v4_checksum_init(skb))
1712 TCP_SKB_CB(skb)->seq = ntohl(th->seq);
1713 TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
1714 skb->len - th->doff * 4);
1715 TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
1716 TCP_SKB_CB(skb)->when = 0;
1717 TCP_SKB_CB(skb)->ip_dsfield = ipv4_get_dsfield(iph);
1718 TCP_SKB_CB(skb)->sacked = 0;
1720 sk = __inet_lookup_skb(&tcp_hashinfo, skb, th->source, th->dest);
1725 if (sk->sk_state == TCP_TIME_WAIT)
1728 if (unlikely(iph->ttl < inet_sk(sk)->min_ttl)) {
1729 NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP);
1730 goto discard_and_relse;
1733 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
1734 goto discard_and_relse;
1737 if (sk_filter(sk, skb))
1738 goto discard_and_relse;
1742 bh_lock_sock_nested(sk);
1744 if (!sock_owned_by_user(sk)) {
1745 #ifdef CONFIG_NET_DMA
1746 struct tcp_sock *tp = tcp_sk(sk);
1747 if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list)
1748 tp->ucopy.dma_chan = net_dma_find_channel();
1749 if (tp->ucopy.dma_chan)
1750 ret = tcp_v4_do_rcv(sk, skb);
1754 if (!tcp_prequeue(sk, skb))
1755 ret = tcp_v4_do_rcv(sk, skb);
1757 } else if (unlikely(sk_add_backlog(sk, skb,
1758 sk->sk_rcvbuf + sk->sk_sndbuf))) {
1760 NET_INC_STATS_BH(net, LINUX_MIB_TCPBACKLOGDROP);
1761 goto discard_and_relse;
1770 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
1773 if (skb->len < (th->doff << 2) || tcp_checksum_complete(skb)) {
1775 TCP_INC_STATS_BH(net, TCP_MIB_INERRS);
1777 tcp_v4_send_reset(NULL, skb);
1781 /* Discard frame. */
1790 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
1791 inet_twsk_put(inet_twsk(sk));
1795 if (skb->len < (th->doff << 2) || tcp_checksum_complete(skb)) {
1796 TCP_INC_STATS_BH(net, TCP_MIB_INERRS);
1797 inet_twsk_put(inet_twsk(sk));
1800 switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) {
1802 struct sock *sk2 = inet_lookup_listener(dev_net(skb->dev),
1804 iph->daddr, th->dest,
1807 inet_twsk_deschedule(inet_twsk(sk), &tcp_death_row);
1808 inet_twsk_put(inet_twsk(sk));
1812 /* Fall through to ACK */
1815 tcp_v4_timewait_ack(sk, skb);
1819 case TCP_TW_SUCCESS:;
1824 struct inet_peer *tcp_v4_get_peer(struct sock *sk, bool *release_it)
1826 struct rtable *rt = (struct rtable *) __sk_dst_get(sk);
1827 struct inet_sock *inet = inet_sk(sk);
1828 struct inet_peer *peer;
1831 inet->cork.fl.u.ip4.daddr != inet->inet_daddr) {
1832 peer = inet_getpeer_v4(inet->inet_daddr, 1);
1836 rt_bind_peer(rt, inet->inet_daddr, 1);
1838 *release_it = false;
1843 EXPORT_SYMBOL(tcp_v4_get_peer);
1845 void *tcp_v4_tw_get_peer(struct sock *sk)
1847 const struct inet_timewait_sock *tw = inet_twsk(sk);
1849 return inet_getpeer_v4(tw->tw_daddr, 1);
1851 EXPORT_SYMBOL(tcp_v4_tw_get_peer);
1853 static struct timewait_sock_ops tcp_timewait_sock_ops = {
1854 .twsk_obj_size = sizeof(struct tcp_timewait_sock),
1855 .twsk_unique = tcp_twsk_unique,
1856 .twsk_destructor= tcp_twsk_destructor,
1857 .twsk_getpeer = tcp_v4_tw_get_peer,
1860 const struct inet_connection_sock_af_ops ipv4_specific = {
1861 .queue_xmit = ip_queue_xmit,
1862 .send_check = tcp_v4_send_check,
1863 .rebuild_header = inet_sk_rebuild_header,
1864 .conn_request = tcp_v4_conn_request,
1865 .syn_recv_sock = tcp_v4_syn_recv_sock,
1866 .get_peer = tcp_v4_get_peer,
1867 .net_header_len = sizeof(struct iphdr),
1868 .setsockopt = ip_setsockopt,
1869 .getsockopt = ip_getsockopt,
1870 .addr2sockaddr = inet_csk_addr2sockaddr,
1871 .sockaddr_len = sizeof(struct sockaddr_in),
1872 .bind_conflict = inet_csk_bind_conflict,
1873 #ifdef CONFIG_COMPAT
1874 .compat_setsockopt = compat_ip_setsockopt,
1875 .compat_getsockopt = compat_ip_getsockopt,
1878 EXPORT_SYMBOL(ipv4_specific);
1880 #ifdef CONFIG_TCP_MD5SIG
1881 static const struct tcp_sock_af_ops tcp_sock_ipv4_specific = {
1882 .md5_lookup = tcp_v4_md5_lookup,
1883 .calc_md5_hash = tcp_v4_md5_hash_skb,
1884 .md5_parse = tcp_v4_parse_md5_keys,
1888 /* NOTE: A lot of things set to zero explicitly by call to
1889 * sk_alloc() so need not be done here.
1891 static int tcp_v4_init_sock(struct sock *sk)
1893 struct inet_connection_sock *icsk = inet_csk(sk);
1897 icsk->icsk_af_ops = &ipv4_specific;
1899 #ifdef CONFIG_TCP_MD5SIG
1900 tcp_sk(sk)->af_specific = &tcp_sock_ipv4_specific;
1906 void tcp_v4_destroy_sock(struct sock *sk)
1908 struct tcp_sock *tp = tcp_sk(sk);
1910 tcp_clear_xmit_timers(sk);
1912 tcp_cleanup_congestion_control(sk);
1914 /* Cleanup up the write buffer. */
1915 tcp_write_queue_purge(sk);
1917 /* Cleans up our, hopefully empty, out_of_order_queue. */
1918 __skb_queue_purge(&tp->out_of_order_queue);
1920 #ifdef CONFIG_TCP_MD5SIG
1921 /* Clean up the MD5 key list, if any */
1922 if (tp->md5sig_info) {
1923 tcp_clear_md5_list(sk);
1924 kfree_rcu(tp->md5sig_info, rcu);
1925 tp->md5sig_info = NULL;
1929 #ifdef CONFIG_NET_DMA
1930 /* Cleans up our sk_async_wait_queue */
1931 __skb_queue_purge(&sk->sk_async_wait_queue);
1934 /* Clean prequeue, it must be empty really */
1935 __skb_queue_purge(&tp->ucopy.prequeue);
1937 /* Clean up a referenced TCP bind bucket. */
1938 if (inet_csk(sk)->icsk_bind_hash)
1942 * If sendmsg cached page exists, toss it.
1944 if (sk->sk_sndmsg_page) {
1945 __free_page(sk->sk_sndmsg_page);
1946 sk->sk_sndmsg_page = NULL;
1949 /* TCP Cookie Transactions */
1950 if (tp->cookie_values != NULL) {
1951 kref_put(&tp->cookie_values->kref,
1952 tcp_cookie_values_release);
1953 tp->cookie_values = NULL;
1956 sk_sockets_allocated_dec(sk);
1957 sock_release_memcg(sk);
1959 EXPORT_SYMBOL(tcp_v4_destroy_sock);
1961 #ifdef CONFIG_PROC_FS
1962 /* Proc filesystem TCP sock list dumping. */
1964 static inline struct inet_timewait_sock *tw_head(struct hlist_nulls_head *head)
1966 return hlist_nulls_empty(head) ? NULL :
1967 list_entry(head->first, struct inet_timewait_sock, tw_node);
1970 static inline struct inet_timewait_sock *tw_next(struct inet_timewait_sock *tw)
1972 return !is_a_nulls(tw->tw_node.next) ?
1973 hlist_nulls_entry(tw->tw_node.next, typeof(*tw), tw_node) : NULL;
1977 * Get next listener socket follow cur. If cur is NULL, get first socket
1978 * starting from bucket given in st->bucket; when st->bucket is zero the
1979 * very first socket in the hash table is returned.
1981 static void *listening_get_next(struct seq_file *seq, void *cur)
1983 struct inet_connection_sock *icsk;
1984 struct hlist_nulls_node *node;
1985 struct sock *sk = cur;
1986 struct inet_listen_hashbucket *ilb;
1987 struct tcp_iter_state *st = seq->private;
1988 struct net *net = seq_file_net(seq);
1991 ilb = &tcp_hashinfo.listening_hash[st->bucket];
1992 spin_lock_bh(&ilb->lock);
1993 sk = sk_nulls_head(&ilb->head);
1997 ilb = &tcp_hashinfo.listening_hash[st->bucket];
2001 if (st->state == TCP_SEQ_STATE_OPENREQ) {
2002 struct request_sock *req = cur;
2004 icsk = inet_csk(st->syn_wait_sk);
2008 if (req->rsk_ops->family == st->family) {
2014 if (++st->sbucket >= icsk->icsk_accept_queue.listen_opt->nr_table_entries)
2017 req = icsk->icsk_accept_queue.listen_opt->syn_table[st->sbucket];
2019 sk = sk_nulls_next(st->syn_wait_sk);
2020 st->state = TCP_SEQ_STATE_LISTENING;
2021 read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
2023 icsk = inet_csk(sk);
2024 read_lock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
2025 if (reqsk_queue_len(&icsk->icsk_accept_queue))
2027 read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
2028 sk = sk_nulls_next(sk);
2031 sk_nulls_for_each_from(sk, node) {
2032 if (!net_eq(sock_net(sk), net))
2034 if (sk->sk_family == st->family) {
2038 icsk = inet_csk(sk);
2039 read_lock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
2040 if (reqsk_queue_len(&icsk->icsk_accept_queue)) {
2042 st->uid = sock_i_uid(sk);
2043 st->syn_wait_sk = sk;
2044 st->state = TCP_SEQ_STATE_OPENREQ;
2048 read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
2050 spin_unlock_bh(&ilb->lock);
2052 if (++st->bucket < INET_LHTABLE_SIZE) {
2053 ilb = &tcp_hashinfo.listening_hash[st->bucket];
2054 spin_lock_bh(&ilb->lock);
2055 sk = sk_nulls_head(&ilb->head);
2063 static void *listening_get_idx(struct seq_file *seq, loff_t *pos)
2065 struct tcp_iter_state *st = seq->private;
2070 rc = listening_get_next(seq, NULL);
2072 while (rc && *pos) {
2073 rc = listening_get_next(seq, rc);
2079 static inline bool empty_bucket(struct tcp_iter_state *st)
2081 return hlist_nulls_empty(&tcp_hashinfo.ehash[st->bucket].chain) &&
2082 hlist_nulls_empty(&tcp_hashinfo.ehash[st->bucket].twchain);
2086 * Get first established socket starting from bucket given in st->bucket.
2087 * If st->bucket is zero, the very first socket in the hash is returned.
2089 static void *established_get_first(struct seq_file *seq)
2091 struct tcp_iter_state *st = seq->private;
2092 struct net *net = seq_file_net(seq);
2096 for (; st->bucket <= tcp_hashinfo.ehash_mask; ++st->bucket) {
2098 struct hlist_nulls_node *node;
2099 struct inet_timewait_sock *tw;
2100 spinlock_t *lock = inet_ehash_lockp(&tcp_hashinfo, st->bucket);
2102 /* Lockless fast path for the common case of empty buckets */
2103 if (empty_bucket(st))
2107 sk_nulls_for_each(sk, node, &tcp_hashinfo.ehash[st->bucket].chain) {
2108 if (sk->sk_family != st->family ||
2109 !net_eq(sock_net(sk), net)) {
2115 st->state = TCP_SEQ_STATE_TIME_WAIT;
2116 inet_twsk_for_each(tw, node,
2117 &tcp_hashinfo.ehash[st->bucket].twchain) {
2118 if (tw->tw_family != st->family ||
2119 !net_eq(twsk_net(tw), net)) {
2125 spin_unlock_bh(lock);
2126 st->state = TCP_SEQ_STATE_ESTABLISHED;
2132 static void *established_get_next(struct seq_file *seq, void *cur)
2134 struct sock *sk = cur;
2135 struct inet_timewait_sock *tw;
2136 struct hlist_nulls_node *node;
2137 struct tcp_iter_state *st = seq->private;
2138 struct net *net = seq_file_net(seq);
2143 if (st->state == TCP_SEQ_STATE_TIME_WAIT) {
2147 while (tw && (tw->tw_family != st->family || !net_eq(twsk_net(tw), net))) {
2154 spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
2155 st->state = TCP_SEQ_STATE_ESTABLISHED;
2157 /* Look for next non empty bucket */
2159 while (++st->bucket <= tcp_hashinfo.ehash_mask &&
2162 if (st->bucket > tcp_hashinfo.ehash_mask)
2165 spin_lock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
2166 sk = sk_nulls_head(&tcp_hashinfo.ehash[st->bucket].chain);
2168 sk = sk_nulls_next(sk);
2170 sk_nulls_for_each_from(sk, node) {
2171 if (sk->sk_family == st->family && net_eq(sock_net(sk), net))
2175 st->state = TCP_SEQ_STATE_TIME_WAIT;
2176 tw = tw_head(&tcp_hashinfo.ehash[st->bucket].twchain);
2184 static void *established_get_idx(struct seq_file *seq, loff_t pos)
2186 struct tcp_iter_state *st = seq->private;
2190 rc = established_get_first(seq);
2193 rc = established_get_next(seq, rc);
2199 static void *tcp_get_idx(struct seq_file *seq, loff_t pos)
2202 struct tcp_iter_state *st = seq->private;
2204 st->state = TCP_SEQ_STATE_LISTENING;
2205 rc = listening_get_idx(seq, &pos);
2208 st->state = TCP_SEQ_STATE_ESTABLISHED;
2209 rc = established_get_idx(seq, pos);
2215 static void *tcp_seek_last_pos(struct seq_file *seq)
2217 struct tcp_iter_state *st = seq->private;
2218 int offset = st->offset;
2219 int orig_num = st->num;
2222 switch (st->state) {
2223 case TCP_SEQ_STATE_OPENREQ:
2224 case TCP_SEQ_STATE_LISTENING:
2225 if (st->bucket >= INET_LHTABLE_SIZE)
2227 st->state = TCP_SEQ_STATE_LISTENING;
2228 rc = listening_get_next(seq, NULL);
2229 while (offset-- && rc)
2230 rc = listening_get_next(seq, rc);
2235 case TCP_SEQ_STATE_ESTABLISHED:
2236 case TCP_SEQ_STATE_TIME_WAIT:
2237 st->state = TCP_SEQ_STATE_ESTABLISHED;
2238 if (st->bucket > tcp_hashinfo.ehash_mask)
2240 rc = established_get_first(seq);
2241 while (offset-- && rc)
2242 rc = established_get_next(seq, rc);
2250 static void *tcp_seq_start(struct seq_file *seq, loff_t *pos)
2252 struct tcp_iter_state *st = seq->private;
2255 if (*pos && *pos == st->last_pos) {
2256 rc = tcp_seek_last_pos(seq);
2261 st->state = TCP_SEQ_STATE_LISTENING;
2265 rc = *pos ? tcp_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
2268 st->last_pos = *pos;
2272 static void *tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2274 struct tcp_iter_state *st = seq->private;
2277 if (v == SEQ_START_TOKEN) {
2278 rc = tcp_get_idx(seq, 0);
2282 switch (st->state) {
2283 case TCP_SEQ_STATE_OPENREQ:
2284 case TCP_SEQ_STATE_LISTENING:
2285 rc = listening_get_next(seq, v);
2287 st->state = TCP_SEQ_STATE_ESTABLISHED;
2290 rc = established_get_first(seq);
2293 case TCP_SEQ_STATE_ESTABLISHED:
2294 case TCP_SEQ_STATE_TIME_WAIT:
2295 rc = established_get_next(seq, v);
2300 st->last_pos = *pos;
2304 static void tcp_seq_stop(struct seq_file *seq, void *v)
2306 struct tcp_iter_state *st = seq->private;
2308 switch (st->state) {
2309 case TCP_SEQ_STATE_OPENREQ:
2311 struct inet_connection_sock *icsk = inet_csk(st->syn_wait_sk);
2312 read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
2314 case TCP_SEQ_STATE_LISTENING:
2315 if (v != SEQ_START_TOKEN)
2316 spin_unlock_bh(&tcp_hashinfo.listening_hash[st->bucket].lock);
2318 case TCP_SEQ_STATE_TIME_WAIT:
2319 case TCP_SEQ_STATE_ESTABLISHED:
2321 spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
2326 int tcp_seq_open(struct inode *inode, struct file *file)
2328 struct tcp_seq_afinfo *afinfo = PDE(inode)->data;
2329 struct tcp_iter_state *s;
2332 err = seq_open_net(inode, file, &afinfo->seq_ops,
2333 sizeof(struct tcp_iter_state));
2337 s = ((struct seq_file *)file->private_data)->private;
2338 s->family = afinfo->family;
2342 EXPORT_SYMBOL(tcp_seq_open);
2344 int tcp_proc_register(struct net *net, struct tcp_seq_afinfo *afinfo)
2347 struct proc_dir_entry *p;
2349 afinfo->seq_ops.start = tcp_seq_start;
2350 afinfo->seq_ops.next = tcp_seq_next;
2351 afinfo->seq_ops.stop = tcp_seq_stop;
2353 p = proc_create_data(afinfo->name, S_IRUGO, net->proc_net,
2354 afinfo->seq_fops, afinfo);
2359 EXPORT_SYMBOL(tcp_proc_register);
2361 void tcp_proc_unregister(struct net *net, struct tcp_seq_afinfo *afinfo)
2363 proc_net_remove(net, afinfo->name);
2365 EXPORT_SYMBOL(tcp_proc_unregister);
2367 static void get_openreq4(const struct sock *sk, const struct request_sock *req,
2368 struct seq_file *f, int i, int uid, int *len)
2370 const struct inet_request_sock *ireq = inet_rsk(req);
2371 int ttd = req->expires - jiffies;
2373 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2374 " %02X %08X:%08X %02X:%08lX %08X %5d %8d %u %d %pK%n",
2377 ntohs(inet_sk(sk)->inet_sport),
2379 ntohs(ireq->rmt_port),
2381 0, 0, /* could print option size, but that is af dependent. */
2382 1, /* timers active (only the expire timer) */
2383 jiffies_to_clock_t(ttd),
2386 0, /* non standard timer */
2387 0, /* open_requests have no inode */
2388 atomic_read(&sk->sk_refcnt),
2393 static void get_tcp4_sock(struct sock *sk, struct seq_file *f, int i, int *len)
2396 unsigned long timer_expires;
2397 const struct tcp_sock *tp = tcp_sk(sk);
2398 const struct inet_connection_sock *icsk = inet_csk(sk);
2399 const struct inet_sock *inet = inet_sk(sk);
2400 __be32 dest = inet->inet_daddr;
2401 __be32 src = inet->inet_rcv_saddr;
2402 __u16 destp = ntohs(inet->inet_dport);
2403 __u16 srcp = ntohs(inet->inet_sport);
2406 if (icsk->icsk_pending == ICSK_TIME_RETRANS) {
2408 timer_expires = icsk->icsk_timeout;
2409 } else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
2411 timer_expires = icsk->icsk_timeout;
2412 } else if (timer_pending(&sk->sk_timer)) {
2414 timer_expires = sk->sk_timer.expires;
2417 timer_expires = jiffies;
2420 if (sk->sk_state == TCP_LISTEN)
2421 rx_queue = sk->sk_ack_backlog;
2424 * because we dont lock socket, we might find a transient negative value
2426 rx_queue = max_t(int, tp->rcv_nxt - tp->copied_seq, 0);
2428 seq_printf(f, "%4d: %08X:%04X %08X:%04X %02X %08X:%08X %02X:%08lX "
2429 "%08X %5d %8d %lu %d %pK %lu %lu %u %u %d%n",
2430 i, src, srcp, dest, destp, sk->sk_state,
2431 tp->write_seq - tp->snd_una,
2434 jiffies_to_clock_t(timer_expires - jiffies),
2435 icsk->icsk_retransmits,
2437 icsk->icsk_probes_out,
2439 atomic_read(&sk->sk_refcnt), sk,
2440 jiffies_to_clock_t(icsk->icsk_rto),
2441 jiffies_to_clock_t(icsk->icsk_ack.ato),
2442 (icsk->icsk_ack.quick << 1) | icsk->icsk_ack.pingpong,
2444 tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh,
2448 static void get_timewait4_sock(const struct inet_timewait_sock *tw,
2449 struct seq_file *f, int i, int *len)
2453 int ttd = tw->tw_ttd - jiffies;
2458 dest = tw->tw_daddr;
2459 src = tw->tw_rcv_saddr;
2460 destp = ntohs(tw->tw_dport);
2461 srcp = ntohs(tw->tw_sport);
2463 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2464 " %02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK%n",
2465 i, src, srcp, dest, destp, tw->tw_substate, 0, 0,
2466 3, jiffies_to_clock_t(ttd), 0, 0, 0, 0,
2467 atomic_read(&tw->tw_refcnt), tw, len);
2472 static int tcp4_seq_show(struct seq_file *seq, void *v)
2474 struct tcp_iter_state *st;
2477 if (v == SEQ_START_TOKEN) {
2478 seq_printf(seq, "%-*s\n", TMPSZ - 1,
2479 " sl local_address rem_address st tx_queue "
2480 "rx_queue tr tm->when retrnsmt uid timeout "
2486 switch (st->state) {
2487 case TCP_SEQ_STATE_LISTENING:
2488 case TCP_SEQ_STATE_ESTABLISHED:
2489 get_tcp4_sock(v, seq, st->num, &len);
2491 case TCP_SEQ_STATE_OPENREQ:
2492 get_openreq4(st->syn_wait_sk, v, seq, st->num, st->uid, &len);
2494 case TCP_SEQ_STATE_TIME_WAIT:
2495 get_timewait4_sock(v, seq, st->num, &len);
2498 seq_printf(seq, "%*s\n", TMPSZ - 1 - len, "");
2503 static const struct file_operations tcp_afinfo_seq_fops = {
2504 .owner = THIS_MODULE,
2505 .open = tcp_seq_open,
2507 .llseek = seq_lseek,
2508 .release = seq_release_net
2511 static struct tcp_seq_afinfo tcp4_seq_afinfo = {
2514 .seq_fops = &tcp_afinfo_seq_fops,
2516 .show = tcp4_seq_show,
2520 static int __net_init tcp4_proc_init_net(struct net *net)
2522 return tcp_proc_register(net, &tcp4_seq_afinfo);
2525 static void __net_exit tcp4_proc_exit_net(struct net *net)
2527 tcp_proc_unregister(net, &tcp4_seq_afinfo);
2530 static struct pernet_operations tcp4_net_ops = {
2531 .init = tcp4_proc_init_net,
2532 .exit = tcp4_proc_exit_net,
2535 int __init tcp4_proc_init(void)
2537 return register_pernet_subsys(&tcp4_net_ops);
2540 void tcp4_proc_exit(void)
2542 unregister_pernet_subsys(&tcp4_net_ops);
2544 #endif /* CONFIG_PROC_FS */
2546 struct sk_buff **tcp4_gro_receive(struct sk_buff **head, struct sk_buff *skb)
2548 const struct iphdr *iph = skb_gro_network_header(skb);
2550 switch (skb->ip_summed) {
2551 case CHECKSUM_COMPLETE:
2552 if (!tcp_v4_check(skb_gro_len(skb), iph->saddr, iph->daddr,
2554 skb->ip_summed = CHECKSUM_UNNECESSARY;
2560 NAPI_GRO_CB(skb)->flush = 1;
2564 return tcp_gro_receive(head, skb);
2567 int tcp4_gro_complete(struct sk_buff *skb)
2569 const struct iphdr *iph = ip_hdr(skb);
2570 struct tcphdr *th = tcp_hdr(skb);
2572 th->check = ~tcp_v4_check(skb->len - skb_transport_offset(skb),
2573 iph->saddr, iph->daddr, 0);
2574 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
2576 return tcp_gro_complete(skb);
2579 struct proto tcp_prot = {
2581 .owner = THIS_MODULE,
2583 .connect = tcp_v4_connect,
2584 .disconnect = tcp_disconnect,
2585 .accept = inet_csk_accept,
2587 .init = tcp_v4_init_sock,
2588 .destroy = tcp_v4_destroy_sock,
2589 .shutdown = tcp_shutdown,
2590 .setsockopt = tcp_setsockopt,
2591 .getsockopt = tcp_getsockopt,
2592 .recvmsg = tcp_recvmsg,
2593 .sendmsg = tcp_sendmsg,
2594 .sendpage = tcp_sendpage,
2595 .backlog_rcv = tcp_v4_do_rcv,
2597 .unhash = inet_unhash,
2598 .get_port = inet_csk_get_port,
2599 .enter_memory_pressure = tcp_enter_memory_pressure,
2600 .sockets_allocated = &tcp_sockets_allocated,
2601 .orphan_count = &tcp_orphan_count,
2602 .memory_allocated = &tcp_memory_allocated,
2603 .memory_pressure = &tcp_memory_pressure,
2604 .sysctl_wmem = sysctl_tcp_wmem,
2605 .sysctl_rmem = sysctl_tcp_rmem,
2606 .max_header = MAX_TCP_HEADER,
2607 .obj_size = sizeof(struct tcp_sock),
2608 .slab_flags = SLAB_DESTROY_BY_RCU,
2609 .twsk_prot = &tcp_timewait_sock_ops,
2610 .rsk_prot = &tcp_request_sock_ops,
2611 .h.hashinfo = &tcp_hashinfo,
2612 .no_autobind = true,
2613 #ifdef CONFIG_COMPAT
2614 .compat_setsockopt = compat_tcp_setsockopt,
2615 .compat_getsockopt = compat_tcp_getsockopt,
2617 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM
2618 .init_cgroup = tcp_init_cgroup,
2619 .destroy_cgroup = tcp_destroy_cgroup,
2620 .proto_cgroup = tcp_proto_cgroup,
2623 EXPORT_SYMBOL(tcp_prot);
2625 static int __net_init tcp_sk_init(struct net *net)
2627 return inet_ctl_sock_create(&net->ipv4.tcp_sock,
2628 PF_INET, SOCK_RAW, IPPROTO_TCP, net);
2631 static void __net_exit tcp_sk_exit(struct net *net)
2633 inet_ctl_sock_destroy(net->ipv4.tcp_sock);
2636 static void __net_exit tcp_sk_exit_batch(struct list_head *net_exit_list)
2638 inet_twsk_purge(&tcp_hashinfo, &tcp_death_row, AF_INET);
2641 static struct pernet_operations __net_initdata tcp_sk_ops = {
2642 .init = tcp_sk_init,
2643 .exit = tcp_sk_exit,
2644 .exit_batch = tcp_sk_exit_batch,
2647 void __init tcp_v4_init(void)
2649 inet_hashinfo_init(&tcp_hashinfo);
2650 if (register_pernet_subsys(&tcp_sk_ops))
2651 panic("Failed to create the TCP control socket.\n");