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/secure_seq.h>
76 #include <net/tcp_memcontrol.h>
77 #include <net/busy_poll.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);
92 #ifdef CONFIG_TCP_MD5SIG
93 static int tcp_v4_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key,
94 __be32 daddr, __be32 saddr, const struct tcphdr *th);
97 struct inet_hashinfo tcp_hashinfo;
98 EXPORT_SYMBOL(tcp_hashinfo);
100 static __u32 tcp_v4_init_sequence(const struct sk_buff *skb)
102 return secure_tcp_sequence_number(ip_hdr(skb)->daddr,
105 tcp_hdr(skb)->source);
108 int tcp_twsk_unique(struct sock *sk, struct sock *sktw, void *twp)
110 const struct tcp_timewait_sock *tcptw = tcp_twsk(sktw);
111 struct tcp_sock *tp = tcp_sk(sk);
113 /* With PAWS, it is safe from the viewpoint
114 of data integrity. Even without PAWS it is safe provided sequence
115 spaces do not overlap i.e. at data rates <= 80Mbit/sec.
117 Actually, the idea is close to VJ's one, only timestamp cache is
118 held not per host, but per port pair and TW bucket is used as state
121 If TW bucket has been already destroyed we fall back to VJ's scheme
122 and use initial timestamp retrieved from peer table.
124 if (tcptw->tw_ts_recent_stamp &&
125 (!twp || (sysctl_tcp_tw_reuse &&
126 get_seconds() - tcptw->tw_ts_recent_stamp > 1))) {
127 tp->write_seq = tcptw->tw_snd_nxt + 65535 + 2;
128 if (tp->write_seq == 0)
130 tp->rx_opt.ts_recent = tcptw->tw_ts_recent;
131 tp->rx_opt.ts_recent_stamp = tcptw->tw_ts_recent_stamp;
138 EXPORT_SYMBOL_GPL(tcp_twsk_unique);
140 /* This will initiate an outgoing connection. */
141 int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
143 struct sockaddr_in *usin = (struct sockaddr_in *)uaddr;
144 struct inet_sock *inet = inet_sk(sk);
145 struct tcp_sock *tp = tcp_sk(sk);
146 __be16 orig_sport, orig_dport;
147 __be32 daddr, nexthop;
151 struct ip_options_rcu *inet_opt;
153 if (addr_len < sizeof(struct sockaddr_in))
156 if (usin->sin_family != AF_INET)
157 return -EAFNOSUPPORT;
159 nexthop = daddr = usin->sin_addr.s_addr;
160 inet_opt = rcu_dereference_protected(inet->inet_opt,
161 sock_owned_by_user(sk));
162 if (inet_opt && inet_opt->opt.srr) {
165 nexthop = inet_opt->opt.faddr;
168 orig_sport = inet->inet_sport;
169 orig_dport = usin->sin_port;
170 fl4 = &inet->cork.fl.u.ip4;
171 rt = ip_route_connect(fl4, nexthop, inet->inet_saddr,
172 RT_CONN_FLAGS(sk), sk->sk_bound_dev_if,
174 orig_sport, orig_dport, sk);
177 if (err == -ENETUNREACH)
178 IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTNOROUTES);
182 if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) {
187 if (!inet_opt || !inet_opt->opt.srr)
190 if (!inet->inet_saddr)
191 inet->inet_saddr = fl4->saddr;
192 sk_rcv_saddr_set(sk, inet->inet_saddr);
194 if (tp->rx_opt.ts_recent_stamp && inet->inet_daddr != daddr) {
195 /* Reset inherited state */
196 tp->rx_opt.ts_recent = 0;
197 tp->rx_opt.ts_recent_stamp = 0;
198 if (likely(!tp->repair))
202 if (tcp_death_row.sysctl_tw_recycle &&
203 !tp->rx_opt.ts_recent_stamp && fl4->daddr == daddr)
204 tcp_fetch_timewait_stamp(sk, &rt->dst);
206 inet->inet_dport = usin->sin_port;
207 sk_daddr_set(sk, daddr);
209 inet_csk(sk)->icsk_ext_hdr_len = 0;
211 inet_csk(sk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
213 tp->rx_opt.mss_clamp = TCP_MSS_DEFAULT;
215 /* Socket identity is still unknown (sport may be zero).
216 * However we set state to SYN-SENT and not releasing socket
217 * lock select source port, enter ourselves into the hash tables and
218 * complete initialization after this.
220 tcp_set_state(sk, TCP_SYN_SENT);
221 err = inet_hash_connect(&tcp_death_row, sk);
227 rt = ip_route_newports(fl4, rt, orig_sport, orig_dport,
228 inet->inet_sport, inet->inet_dport, sk);
234 /* OK, now commit destination to socket. */
235 sk->sk_gso_type = SKB_GSO_TCPV4;
236 sk_setup_caps(sk, &rt->dst);
238 if (!tp->write_seq && likely(!tp->repair))
239 tp->write_seq = secure_tcp_sequence_number(inet->inet_saddr,
244 inet->inet_id = tp->write_seq ^ jiffies;
246 err = tcp_connect(sk);
256 * This unhashes the socket and releases the local port,
259 tcp_set_state(sk, TCP_CLOSE);
261 sk->sk_route_caps = 0;
262 inet->inet_dport = 0;
265 EXPORT_SYMBOL(tcp_v4_connect);
268 * This routine reacts to ICMP_FRAG_NEEDED mtu indications as defined in RFC1191.
269 * It can be called through tcp_release_cb() if socket was owned by user
270 * at the time tcp_v4_err() was called to handle ICMP message.
272 void tcp_v4_mtu_reduced(struct sock *sk)
274 struct dst_entry *dst;
275 struct inet_sock *inet = inet_sk(sk);
276 u32 mtu = tcp_sk(sk)->mtu_info;
278 dst = inet_csk_update_pmtu(sk, mtu);
282 /* Something is about to be wrong... Remember soft error
283 * for the case, if this connection will not able to recover.
285 if (mtu < dst_mtu(dst) && ip_dont_fragment(sk, dst))
286 sk->sk_err_soft = EMSGSIZE;
290 if (inet->pmtudisc != IP_PMTUDISC_DONT &&
291 ip_sk_accept_pmtu(sk) &&
292 inet_csk(sk)->icsk_pmtu_cookie > mtu) {
293 tcp_sync_mss(sk, mtu);
295 /* Resend the TCP packet because it's
296 * clear that the old packet has been
297 * dropped. This is the new "fast" path mtu
300 tcp_simple_retransmit(sk);
301 } /* else let the usual retransmit timer handle it */
303 EXPORT_SYMBOL(tcp_v4_mtu_reduced);
305 static void do_redirect(struct sk_buff *skb, struct sock *sk)
307 struct dst_entry *dst = __sk_dst_check(sk, 0);
310 dst->ops->redirect(dst, sk, skb);
314 /* handle ICMP messages on TCP_NEW_SYN_RECV request sockets */
315 void tcp_req_err(struct sock *sk, u32 seq)
317 struct request_sock *req = inet_reqsk(sk);
318 struct net *net = sock_net(sk);
320 /* ICMPs are not backlogged, hence we cannot get
321 * an established socket here.
325 if (seq != tcp_rsk(req)->snt_isn) {
326 NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
329 * Still in SYN_RECV, just remove it silently.
330 * There is no good way to pass the error to the newly
331 * created socket, and POSIX does not want network
332 * errors returned from accept().
334 inet_csk_reqsk_queue_drop(req->rsk_listener, req);
335 NET_INC_STATS_BH(net, LINUX_MIB_LISTENDROPS);
339 EXPORT_SYMBOL(tcp_req_err);
342 * This routine is called by the ICMP module when it gets some
343 * sort of error condition. If err < 0 then the socket should
344 * be closed and the error returned to the user. If err > 0
345 * it's just the icmp type << 8 | icmp code. After adjustment
346 * header points to the first 8 bytes of the tcp header. We need
347 * to find the appropriate port.
349 * The locking strategy used here is very "optimistic". When
350 * someone else accesses the socket the ICMP is just dropped
351 * and for some paths there is no check at all.
352 * A more general error queue to queue errors for later handling
353 * is probably better.
357 void tcp_v4_err(struct sk_buff *icmp_skb, u32 info)
359 const struct iphdr *iph = (const struct iphdr *)icmp_skb->data;
360 struct tcphdr *th = (struct tcphdr *)(icmp_skb->data + (iph->ihl << 2));
361 struct inet_connection_sock *icsk;
363 struct inet_sock *inet;
364 const int type = icmp_hdr(icmp_skb)->type;
365 const int code = icmp_hdr(icmp_skb)->code;
368 struct request_sock *fastopen;
372 struct net *net = dev_net(icmp_skb->dev);
374 sk = __inet_lookup_established(net, &tcp_hashinfo, iph->daddr,
375 th->dest, iph->saddr, ntohs(th->source),
378 ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS);
381 if (sk->sk_state == TCP_TIME_WAIT) {
382 inet_twsk_put(inet_twsk(sk));
385 seq = ntohl(th->seq);
386 if (sk->sk_state == TCP_NEW_SYN_RECV)
387 return tcp_req_err(sk, seq);
390 /* If too many ICMPs get dropped on busy
391 * servers this needs to be solved differently.
392 * We do take care of PMTU discovery (RFC1191) special case :
393 * we can receive locally generated ICMP messages while socket is held.
395 if (sock_owned_by_user(sk)) {
396 if (!(type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED))
397 NET_INC_STATS_BH(net, LINUX_MIB_LOCKDROPPEDICMPS);
399 if (sk->sk_state == TCP_CLOSE)
402 if (unlikely(iph->ttl < inet_sk(sk)->min_ttl)) {
403 NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP);
409 /* XXX (TFO) - tp->snd_una should be ISN (tcp_create_openreq_child() */
410 fastopen = tp->fastopen_rsk;
411 snd_una = fastopen ? tcp_rsk(fastopen)->snt_isn : tp->snd_una;
412 if (sk->sk_state != TCP_LISTEN &&
413 !between(seq, snd_una, tp->snd_nxt)) {
414 NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
420 do_redirect(icmp_skb, sk);
422 case ICMP_SOURCE_QUENCH:
423 /* Just silently ignore these. */
425 case ICMP_PARAMETERPROB:
428 case ICMP_DEST_UNREACH:
429 if (code > NR_ICMP_UNREACH)
432 if (code == ICMP_FRAG_NEEDED) { /* PMTU discovery (RFC1191) */
433 /* We are not interested in TCP_LISTEN and open_requests
434 * (SYN-ACKs send out by Linux are always <576bytes so
435 * they should go through unfragmented).
437 if (sk->sk_state == TCP_LISTEN)
441 if (!sock_owned_by_user(sk)) {
442 tcp_v4_mtu_reduced(sk);
444 if (!test_and_set_bit(TCP_MTU_REDUCED_DEFERRED, &tp->tsq_flags))
450 err = icmp_err_convert[code].errno;
451 /* check if icmp_skb allows revert of backoff
452 * (see draft-zimmermann-tcp-lcd) */
453 if (code != ICMP_NET_UNREACH && code != ICMP_HOST_UNREACH)
455 if (seq != tp->snd_una || !icsk->icsk_retransmits ||
456 !icsk->icsk_backoff || fastopen)
459 if (sock_owned_by_user(sk))
462 icsk->icsk_backoff--;
463 icsk->icsk_rto = tp->srtt_us ? __tcp_set_rto(tp) :
465 icsk->icsk_rto = inet_csk_rto_backoff(icsk, TCP_RTO_MAX);
467 skb = tcp_write_queue_head(sk);
470 remaining = icsk->icsk_rto -
472 tcp_time_stamp - tcp_skb_timestamp(skb));
475 inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
476 remaining, TCP_RTO_MAX);
478 /* RTO revert clocked out retransmission.
479 * Will retransmit now */
480 tcp_retransmit_timer(sk);
484 case ICMP_TIME_EXCEEDED:
491 switch (sk->sk_state) {
494 /* Only in fast or simultaneous open. If a fast open socket is
495 * is already accepted it is treated as a connected one below.
497 if (fastopen && !fastopen->sk)
500 if (!sock_owned_by_user(sk)) {
503 sk->sk_error_report(sk);
507 sk->sk_err_soft = err;
512 /* If we've already connected we will keep trying
513 * until we time out, or the user gives up.
515 * rfc1122 4.2.3.9 allows to consider as hard errors
516 * only PROTO_UNREACH and PORT_UNREACH (well, FRAG_FAILED too,
517 * but it is obsoleted by pmtu discovery).
519 * Note, that in modern internet, where routing is unreliable
520 * and in each dark corner broken firewalls sit, sending random
521 * errors ordered by their masters even this two messages finally lose
522 * their original sense (even Linux sends invalid PORT_UNREACHs)
524 * Now we are in compliance with RFCs.
529 if (!sock_owned_by_user(sk) && inet->recverr) {
531 sk->sk_error_report(sk);
532 } else { /* Only an error on timeout */
533 sk->sk_err_soft = err;
541 void __tcp_v4_send_check(struct sk_buff *skb, __be32 saddr, __be32 daddr)
543 struct tcphdr *th = tcp_hdr(skb);
545 if (skb->ip_summed == CHECKSUM_PARTIAL) {
546 th->check = ~tcp_v4_check(skb->len, saddr, daddr, 0);
547 skb->csum_start = skb_transport_header(skb) - skb->head;
548 skb->csum_offset = offsetof(struct tcphdr, check);
550 th->check = tcp_v4_check(skb->len, saddr, daddr,
557 /* This routine computes an IPv4 TCP checksum. */
558 void tcp_v4_send_check(struct sock *sk, struct sk_buff *skb)
560 const struct inet_sock *inet = inet_sk(sk);
562 __tcp_v4_send_check(skb, inet->inet_saddr, inet->inet_daddr);
564 EXPORT_SYMBOL(tcp_v4_send_check);
567 * This routine will send an RST to the other tcp.
569 * Someone asks: why I NEVER use socket parameters (TOS, TTL etc.)
571 * Answer: if a packet caused RST, it is not for a socket
572 * existing in our system, if it is matched to a socket,
573 * it is just duplicate segment or bug in other side's TCP.
574 * So that we build reply only basing on parameters
575 * arrived with segment.
576 * Exception: precedence violation. We do not implement it in any case.
579 static void tcp_v4_send_reset(const struct sock *sk, struct sk_buff *skb)
581 const struct tcphdr *th = tcp_hdr(skb);
584 #ifdef CONFIG_TCP_MD5SIG
585 __be32 opt[(TCPOLEN_MD5SIG_ALIGNED >> 2)];
588 struct ip_reply_arg arg;
589 #ifdef CONFIG_TCP_MD5SIG
590 struct tcp_md5sig_key *key;
591 const __u8 *hash_location = NULL;
592 unsigned char newhash[16];
594 struct sock *sk1 = NULL;
598 /* Never send a reset in response to a reset. */
602 /* If sk not NULL, it means we did a successful lookup and incoming
603 * route had to be correct. prequeue might have dropped our dst.
605 if (!sk && skb_rtable(skb)->rt_type != RTN_LOCAL)
608 /* Swap the send and the receive. */
609 memset(&rep, 0, sizeof(rep));
610 rep.th.dest = th->source;
611 rep.th.source = th->dest;
612 rep.th.doff = sizeof(struct tcphdr) / 4;
616 rep.th.seq = th->ack_seq;
619 rep.th.ack_seq = htonl(ntohl(th->seq) + th->syn + th->fin +
620 skb->len - (th->doff << 2));
623 memset(&arg, 0, sizeof(arg));
624 arg.iov[0].iov_base = (unsigned char *)&rep;
625 arg.iov[0].iov_len = sizeof(rep.th);
627 net = sk ? sock_net(sk) : dev_net(skb_dst(skb)->dev);
628 #ifdef CONFIG_TCP_MD5SIG
629 hash_location = tcp_parse_md5sig_option(th);
630 if (!sk && hash_location) {
632 * active side is lost. Try to find listening socket through
633 * source port, and then find md5 key through listening socket.
634 * we are not loose security here:
635 * Incoming packet is checked with md5 hash with finding key,
636 * no RST generated if md5 hash doesn't match.
638 sk1 = __inet_lookup_listener(net,
639 &tcp_hashinfo, ip_hdr(skb)->saddr,
640 th->source, ip_hdr(skb)->daddr,
641 ntohs(th->source), inet_iif(skb));
642 /* don't send rst if it can't find key */
646 key = tcp_md5_do_lookup(sk1, (union tcp_md5_addr *)
647 &ip_hdr(skb)->saddr, AF_INET);
651 genhash = tcp_v4_md5_hash_skb(newhash, key, NULL, skb);
652 if (genhash || memcmp(hash_location, newhash, 16) != 0)
655 key = sk ? tcp_md5_do_lookup(sk, (union tcp_md5_addr *)
661 rep.opt[0] = htonl((TCPOPT_NOP << 24) |
663 (TCPOPT_MD5SIG << 8) |
665 /* Update length and the length the header thinks exists */
666 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED;
667 rep.th.doff = arg.iov[0].iov_len / 4;
669 tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[1],
670 key, ip_hdr(skb)->saddr,
671 ip_hdr(skb)->daddr, &rep.th);
674 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
675 ip_hdr(skb)->saddr, /* XXX */
676 arg.iov[0].iov_len, IPPROTO_TCP, 0);
677 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
678 arg.flags = (sk && inet_sk(sk)->transparent) ? IP_REPLY_ARG_NOSRCCHECK : 0;
679 /* When socket is gone, all binding information is lost.
680 * routing might fail in this case. No choice here, if we choose to force
681 * input interface, we will misroute in case of asymmetric route.
684 arg.bound_dev_if = sk->sk_bound_dev_if;
686 arg.tos = ip_hdr(skb)->tos;
687 ip_send_unicast_reply(*this_cpu_ptr(net->ipv4.tcp_sk),
688 skb, &TCP_SKB_CB(skb)->header.h4.opt,
689 ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
690 &arg, arg.iov[0].iov_len);
692 TCP_INC_STATS_BH(net, TCP_MIB_OUTSEGS);
693 TCP_INC_STATS_BH(net, TCP_MIB_OUTRSTS);
695 #ifdef CONFIG_TCP_MD5SIG
704 /* The code following below sending ACKs in SYN-RECV and TIME-WAIT states
705 outside socket context is ugly, certainly. What can I do?
708 static void tcp_v4_send_ack(struct sk_buff *skb, u32 seq, u32 ack,
709 u32 win, u32 tsval, u32 tsecr, int oif,
710 struct tcp_md5sig_key *key,
711 int reply_flags, u8 tos)
713 const struct tcphdr *th = tcp_hdr(skb);
716 __be32 opt[(TCPOLEN_TSTAMP_ALIGNED >> 2)
717 #ifdef CONFIG_TCP_MD5SIG
718 + (TCPOLEN_MD5SIG_ALIGNED >> 2)
722 struct ip_reply_arg arg;
723 struct net *net = dev_net(skb_dst(skb)->dev);
725 memset(&rep.th, 0, sizeof(struct tcphdr));
726 memset(&arg, 0, sizeof(arg));
728 arg.iov[0].iov_base = (unsigned char *)&rep;
729 arg.iov[0].iov_len = sizeof(rep.th);
731 rep.opt[0] = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
732 (TCPOPT_TIMESTAMP << 8) |
734 rep.opt[1] = htonl(tsval);
735 rep.opt[2] = htonl(tsecr);
736 arg.iov[0].iov_len += TCPOLEN_TSTAMP_ALIGNED;
739 /* Swap the send and the receive. */
740 rep.th.dest = th->source;
741 rep.th.source = th->dest;
742 rep.th.doff = arg.iov[0].iov_len / 4;
743 rep.th.seq = htonl(seq);
744 rep.th.ack_seq = htonl(ack);
746 rep.th.window = htons(win);
748 #ifdef CONFIG_TCP_MD5SIG
750 int offset = (tsecr) ? 3 : 0;
752 rep.opt[offset++] = htonl((TCPOPT_NOP << 24) |
754 (TCPOPT_MD5SIG << 8) |
756 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED;
757 rep.th.doff = arg.iov[0].iov_len/4;
759 tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[offset],
760 key, ip_hdr(skb)->saddr,
761 ip_hdr(skb)->daddr, &rep.th);
764 arg.flags = reply_flags;
765 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
766 ip_hdr(skb)->saddr, /* XXX */
767 arg.iov[0].iov_len, IPPROTO_TCP, 0);
768 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
770 arg.bound_dev_if = oif;
772 ip_send_unicast_reply(*this_cpu_ptr(net->ipv4.tcp_sk),
773 skb, &TCP_SKB_CB(skb)->header.h4.opt,
774 ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
775 &arg, arg.iov[0].iov_len);
777 TCP_INC_STATS_BH(net, TCP_MIB_OUTSEGS);
780 static void tcp_v4_timewait_ack(struct sock *sk, struct sk_buff *skb)
782 struct inet_timewait_sock *tw = inet_twsk(sk);
783 struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
785 tcp_v4_send_ack(skb, tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
786 tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
787 tcp_time_stamp + tcptw->tw_ts_offset,
790 tcp_twsk_md5_key(tcptw),
791 tw->tw_transparent ? IP_REPLY_ARG_NOSRCCHECK : 0,
798 static void tcp_v4_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb,
799 struct request_sock *req)
801 /* sk->sk_state == TCP_LISTEN -> for regular TCP_SYN_RECV
802 * sk->sk_state == TCP_SYN_RECV -> for Fast Open.
804 tcp_v4_send_ack(skb, (sk->sk_state == TCP_LISTEN) ?
805 tcp_rsk(req)->snt_isn + 1 : tcp_sk(sk)->snd_nxt,
806 tcp_rsk(req)->rcv_nxt, req->rsk_rcv_wnd,
810 tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&ip_hdr(skb)->daddr,
812 inet_rsk(req)->no_srccheck ? IP_REPLY_ARG_NOSRCCHECK : 0,
817 * Send a SYN-ACK after having received a SYN.
818 * This still operates on a request_sock only, not on a big
821 static int tcp_v4_send_synack(const struct sock *sk, struct dst_entry *dst,
823 struct request_sock *req,
824 struct tcp_fastopen_cookie *foc,
827 const struct inet_request_sock *ireq = inet_rsk(req);
832 /* First, grab a route. */
833 if (!dst && (dst = inet_csk_route_req(sk, &fl4, req)) == NULL)
836 skb = tcp_make_synack(sk, dst, req, foc, attach_req);
839 __tcp_v4_send_check(skb, ireq->ir_loc_addr, ireq->ir_rmt_addr);
841 err = ip_build_and_send_pkt(skb, sk, ireq->ir_loc_addr,
844 err = net_xmit_eval(err);
851 * IPv4 request_sock destructor.
853 static void tcp_v4_reqsk_destructor(struct request_sock *req)
855 kfree(inet_rsk(req)->opt);
859 #ifdef CONFIG_TCP_MD5SIG
861 * RFC2385 MD5 checksumming requires a mapping of
862 * IP address->MD5 Key.
863 * We need to maintain these in the sk structure.
866 /* Find the Key structure for an address. */
867 struct tcp_md5sig_key *tcp_md5_do_lookup(const struct sock *sk,
868 const union tcp_md5_addr *addr,
871 const struct tcp_sock *tp = tcp_sk(sk);
872 struct tcp_md5sig_key *key;
873 unsigned int size = sizeof(struct in_addr);
874 const struct tcp_md5sig_info *md5sig;
876 /* caller either holds rcu_read_lock() or socket lock */
877 md5sig = rcu_dereference_check(tp->md5sig_info,
878 sock_owned_by_user(sk) ||
879 lockdep_is_held((spinlock_t *)&sk->sk_lock.slock));
882 #if IS_ENABLED(CONFIG_IPV6)
883 if (family == AF_INET6)
884 size = sizeof(struct in6_addr);
886 hlist_for_each_entry_rcu(key, &md5sig->head, node) {
887 if (key->family != family)
889 if (!memcmp(&key->addr, addr, size))
894 EXPORT_SYMBOL(tcp_md5_do_lookup);
896 struct tcp_md5sig_key *tcp_v4_md5_lookup(const struct sock *sk,
897 const struct sock *addr_sk)
899 const union tcp_md5_addr *addr;
901 addr = (const union tcp_md5_addr *)&addr_sk->sk_daddr;
902 return tcp_md5_do_lookup(sk, addr, AF_INET);
904 EXPORT_SYMBOL(tcp_v4_md5_lookup);
906 /* This can be called on a newly created socket, from other files */
907 int tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr,
908 int family, const u8 *newkey, u8 newkeylen, gfp_t gfp)
910 /* Add Key to the list */
911 struct tcp_md5sig_key *key;
912 struct tcp_sock *tp = tcp_sk(sk);
913 struct tcp_md5sig_info *md5sig;
915 key = tcp_md5_do_lookup(sk, addr, family);
917 /* Pre-existing entry - just update that one. */
918 memcpy(key->key, newkey, newkeylen);
919 key->keylen = newkeylen;
923 md5sig = rcu_dereference_protected(tp->md5sig_info,
924 sock_owned_by_user(sk));
926 md5sig = kmalloc(sizeof(*md5sig), gfp);
930 sk_nocaps_add(sk, NETIF_F_GSO_MASK);
931 INIT_HLIST_HEAD(&md5sig->head);
932 rcu_assign_pointer(tp->md5sig_info, md5sig);
935 key = sock_kmalloc(sk, sizeof(*key), gfp);
938 if (!tcp_alloc_md5sig_pool()) {
939 sock_kfree_s(sk, key, sizeof(*key));
943 memcpy(key->key, newkey, newkeylen);
944 key->keylen = newkeylen;
945 key->family = family;
946 memcpy(&key->addr, addr,
947 (family == AF_INET6) ? sizeof(struct in6_addr) :
948 sizeof(struct in_addr));
949 hlist_add_head_rcu(&key->node, &md5sig->head);
952 EXPORT_SYMBOL(tcp_md5_do_add);
954 int tcp_md5_do_del(struct sock *sk, const union tcp_md5_addr *addr, int family)
956 struct tcp_md5sig_key *key;
958 key = tcp_md5_do_lookup(sk, addr, family);
961 hlist_del_rcu(&key->node);
962 atomic_sub(sizeof(*key), &sk->sk_omem_alloc);
966 EXPORT_SYMBOL(tcp_md5_do_del);
968 static void tcp_clear_md5_list(struct sock *sk)
970 struct tcp_sock *tp = tcp_sk(sk);
971 struct tcp_md5sig_key *key;
972 struct hlist_node *n;
973 struct tcp_md5sig_info *md5sig;
975 md5sig = rcu_dereference_protected(tp->md5sig_info, 1);
977 hlist_for_each_entry_safe(key, n, &md5sig->head, node) {
978 hlist_del_rcu(&key->node);
979 atomic_sub(sizeof(*key), &sk->sk_omem_alloc);
984 static int tcp_v4_parse_md5_keys(struct sock *sk, char __user *optval,
987 struct tcp_md5sig cmd;
988 struct sockaddr_in *sin = (struct sockaddr_in *)&cmd.tcpm_addr;
990 if (optlen < sizeof(cmd))
993 if (copy_from_user(&cmd, optval, sizeof(cmd)))
996 if (sin->sin_family != AF_INET)
999 if (!cmd.tcpm_keylen)
1000 return tcp_md5_do_del(sk, (union tcp_md5_addr *)&sin->sin_addr.s_addr,
1003 if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN)
1006 return tcp_md5_do_add(sk, (union tcp_md5_addr *)&sin->sin_addr.s_addr,
1007 AF_INET, cmd.tcpm_key, cmd.tcpm_keylen,
1011 static int tcp_v4_md5_hash_pseudoheader(struct tcp_md5sig_pool *hp,
1012 __be32 daddr, __be32 saddr, int nbytes)
1014 struct tcp4_pseudohdr *bp;
1015 struct scatterlist sg;
1017 bp = &hp->md5_blk.ip4;
1020 * 1. the TCP pseudo-header (in the order: source IP address,
1021 * destination IP address, zero-padded protocol number, and
1027 bp->protocol = IPPROTO_TCP;
1028 bp->len = cpu_to_be16(nbytes);
1030 sg_init_one(&sg, bp, sizeof(*bp));
1031 return crypto_hash_update(&hp->md5_desc, &sg, sizeof(*bp));
1034 static int tcp_v4_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key,
1035 __be32 daddr, __be32 saddr, const struct tcphdr *th)
1037 struct tcp_md5sig_pool *hp;
1038 struct hash_desc *desc;
1040 hp = tcp_get_md5sig_pool();
1042 goto clear_hash_noput;
1043 desc = &hp->md5_desc;
1045 if (crypto_hash_init(desc))
1047 if (tcp_v4_md5_hash_pseudoheader(hp, daddr, saddr, th->doff << 2))
1049 if (tcp_md5_hash_header(hp, th))
1051 if (tcp_md5_hash_key(hp, key))
1053 if (crypto_hash_final(desc, md5_hash))
1056 tcp_put_md5sig_pool();
1060 tcp_put_md5sig_pool();
1062 memset(md5_hash, 0, 16);
1066 int tcp_v4_md5_hash_skb(char *md5_hash, const struct tcp_md5sig_key *key,
1067 const struct sock *sk,
1068 const struct sk_buff *skb)
1070 struct tcp_md5sig_pool *hp;
1071 struct hash_desc *desc;
1072 const struct tcphdr *th = tcp_hdr(skb);
1073 __be32 saddr, daddr;
1075 if (sk) { /* valid for establish/request sockets */
1076 saddr = sk->sk_rcv_saddr;
1077 daddr = sk->sk_daddr;
1079 const struct iphdr *iph = ip_hdr(skb);
1084 hp = tcp_get_md5sig_pool();
1086 goto clear_hash_noput;
1087 desc = &hp->md5_desc;
1089 if (crypto_hash_init(desc))
1092 if (tcp_v4_md5_hash_pseudoheader(hp, daddr, saddr, skb->len))
1094 if (tcp_md5_hash_header(hp, th))
1096 if (tcp_md5_hash_skb_data(hp, skb, th->doff << 2))
1098 if (tcp_md5_hash_key(hp, key))
1100 if (crypto_hash_final(desc, md5_hash))
1103 tcp_put_md5sig_pool();
1107 tcp_put_md5sig_pool();
1109 memset(md5_hash, 0, 16);
1112 EXPORT_SYMBOL(tcp_v4_md5_hash_skb);
1116 /* Called with rcu_read_lock() */
1117 static bool tcp_v4_inbound_md5_hash(const struct sock *sk,
1118 const struct sk_buff *skb)
1120 #ifdef CONFIG_TCP_MD5SIG
1122 * This gets called for each TCP segment that arrives
1123 * so we want to be efficient.
1124 * We have 3 drop cases:
1125 * o No MD5 hash and one expected.
1126 * o MD5 hash and we're not expecting one.
1127 * o MD5 hash and its wrong.
1129 const __u8 *hash_location = NULL;
1130 struct tcp_md5sig_key *hash_expected;
1131 const struct iphdr *iph = ip_hdr(skb);
1132 const struct tcphdr *th = tcp_hdr(skb);
1134 unsigned char newhash[16];
1136 hash_expected = tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&iph->saddr,
1138 hash_location = tcp_parse_md5sig_option(th);
1140 /* We've parsed the options - do we have a hash? */
1141 if (!hash_expected && !hash_location)
1144 if (hash_expected && !hash_location) {
1145 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5NOTFOUND);
1149 if (!hash_expected && hash_location) {
1150 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5UNEXPECTED);
1154 /* Okay, so this is hash_expected and hash_location -
1155 * so we need to calculate the checksum.
1157 genhash = tcp_v4_md5_hash_skb(newhash,
1161 if (genhash || memcmp(hash_location, newhash, 16) != 0) {
1162 net_info_ratelimited("MD5 Hash failed for (%pI4, %d)->(%pI4, %d)%s\n",
1163 &iph->saddr, ntohs(th->source),
1164 &iph->daddr, ntohs(th->dest),
1165 genhash ? " tcp_v4_calc_md5_hash failed"
1174 static void tcp_v4_init_req(struct request_sock *req,
1175 const struct sock *sk_listener,
1176 struct sk_buff *skb)
1178 struct inet_request_sock *ireq = inet_rsk(req);
1180 sk_rcv_saddr_set(req_to_sk(req), ip_hdr(skb)->daddr);
1181 sk_daddr_set(req_to_sk(req), ip_hdr(skb)->saddr);
1182 ireq->no_srccheck = inet_sk(sk_listener)->transparent;
1183 ireq->opt = tcp_v4_save_options(skb);
1186 static struct dst_entry *tcp_v4_route_req(const struct sock *sk,
1188 const struct request_sock *req,
1191 struct dst_entry *dst = inet_csk_route_req(sk, &fl->u.ip4, req);
1194 if (fl->u.ip4.daddr == inet_rsk(req)->ir_rmt_addr)
1203 struct request_sock_ops tcp_request_sock_ops __read_mostly = {
1205 .obj_size = sizeof(struct tcp_request_sock),
1206 .rtx_syn_ack = tcp_rtx_synack,
1207 .send_ack = tcp_v4_reqsk_send_ack,
1208 .destructor = tcp_v4_reqsk_destructor,
1209 .send_reset = tcp_v4_send_reset,
1210 .syn_ack_timeout = tcp_syn_ack_timeout,
1213 static const struct tcp_request_sock_ops tcp_request_sock_ipv4_ops = {
1214 .mss_clamp = TCP_MSS_DEFAULT,
1215 #ifdef CONFIG_TCP_MD5SIG
1216 .req_md5_lookup = tcp_v4_md5_lookup,
1217 .calc_md5_hash = tcp_v4_md5_hash_skb,
1219 .init_req = tcp_v4_init_req,
1220 #ifdef CONFIG_SYN_COOKIES
1221 .cookie_init_seq = cookie_v4_init_sequence,
1223 .route_req = tcp_v4_route_req,
1224 .init_seq = tcp_v4_init_sequence,
1225 .send_synack = tcp_v4_send_synack,
1228 int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
1230 /* Never answer to SYNs send to broadcast or multicast */
1231 if (skb_rtable(skb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
1234 return tcp_conn_request(&tcp_request_sock_ops,
1235 &tcp_request_sock_ipv4_ops, sk, skb);
1238 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
1241 EXPORT_SYMBOL(tcp_v4_conn_request);
1245 * The three way handshake has completed - we got a valid synack -
1246 * now create the new socket.
1248 struct sock *tcp_v4_syn_recv_sock(const struct sock *sk, struct sk_buff *skb,
1249 struct request_sock *req,
1250 struct dst_entry *dst,
1251 struct request_sock *req_unhash,
1254 struct inet_request_sock *ireq;
1255 struct inet_sock *newinet;
1256 struct tcp_sock *newtp;
1258 #ifdef CONFIG_TCP_MD5SIG
1259 struct tcp_md5sig_key *key;
1261 struct ip_options_rcu *inet_opt;
1263 if (sk_acceptq_is_full(sk))
1266 newsk = tcp_create_openreq_child(sk, req, skb);
1270 newsk->sk_gso_type = SKB_GSO_TCPV4;
1271 inet_sk_rx_dst_set(newsk, skb);
1273 newtp = tcp_sk(newsk);
1274 newinet = inet_sk(newsk);
1275 ireq = inet_rsk(req);
1276 sk_daddr_set(newsk, ireq->ir_rmt_addr);
1277 sk_rcv_saddr_set(newsk, ireq->ir_loc_addr);
1278 newinet->inet_saddr = ireq->ir_loc_addr;
1279 inet_opt = ireq->opt;
1280 rcu_assign_pointer(newinet->inet_opt, inet_opt);
1282 newinet->mc_index = inet_iif(skb);
1283 newinet->mc_ttl = ip_hdr(skb)->ttl;
1284 newinet->rcv_tos = ip_hdr(skb)->tos;
1285 inet_csk(newsk)->icsk_ext_hdr_len = 0;
1287 inet_csk(newsk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
1288 newinet->inet_id = newtp->write_seq ^ jiffies;
1291 dst = inet_csk_route_child_sock(sk, newsk, req);
1295 /* syncookie case : see end of cookie_v4_check() */
1297 sk_setup_caps(newsk, dst);
1299 tcp_ca_openreq_child(newsk, dst);
1301 tcp_sync_mss(newsk, dst_mtu(dst));
1302 newtp->advmss = dst_metric_advmss(dst);
1303 if (tcp_sk(sk)->rx_opt.user_mss &&
1304 tcp_sk(sk)->rx_opt.user_mss < newtp->advmss)
1305 newtp->advmss = tcp_sk(sk)->rx_opt.user_mss;
1307 tcp_initialize_rcv_mss(newsk);
1309 #ifdef CONFIG_TCP_MD5SIG
1310 /* Copy over the MD5 key from the original socket */
1311 key = tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&newinet->inet_daddr,
1315 * We're using one, so create a matching key
1316 * on the newsk structure. If we fail to get
1317 * memory, then we end up not copying the key
1320 tcp_md5_do_add(newsk, (union tcp_md5_addr *)&newinet->inet_daddr,
1321 AF_INET, key->key, key->keylen, GFP_ATOMIC);
1322 sk_nocaps_add(newsk, NETIF_F_GSO_MASK);
1326 if (__inet_inherit_port(sk, newsk) < 0)
1328 *own_req = inet_ehash_nolisten(newsk, req_to_sk(req_unhash));
1333 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
1337 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
1340 inet_csk_prepare_forced_close(newsk);
1344 EXPORT_SYMBOL(tcp_v4_syn_recv_sock);
1346 static struct sock *tcp_v4_cookie_check(struct sock *sk, struct sk_buff *skb)
1348 #ifdef CONFIG_SYN_COOKIES
1349 const struct tcphdr *th = tcp_hdr(skb);
1352 sk = cookie_v4_check(sk, skb);
1357 /* The socket must have it's spinlock held when we get
1358 * here, unless it is a TCP_LISTEN socket.
1360 * We have a potential double-lock case here, so even when
1361 * doing backlog processing we use the BH locking scheme.
1362 * This is because we cannot sleep with the original spinlock
1365 int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
1369 if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
1370 struct dst_entry *dst = sk->sk_rx_dst;
1372 sock_rps_save_rxhash(sk, skb);
1373 sk_mark_napi_id(sk, skb);
1375 if (inet_sk(sk)->rx_dst_ifindex != skb->skb_iif ||
1376 !dst->ops->check(dst, 0)) {
1378 sk->sk_rx_dst = NULL;
1381 tcp_rcv_established(sk, skb, tcp_hdr(skb), skb->len);
1385 if (tcp_checksum_complete(skb))
1388 if (sk->sk_state == TCP_LISTEN) {
1389 struct sock *nsk = tcp_v4_cookie_check(sk, skb);
1394 sock_rps_save_rxhash(nsk, skb);
1395 sk_mark_napi_id(nsk, skb);
1396 if (tcp_child_process(sk, nsk, skb)) {
1403 sock_rps_save_rxhash(sk, skb);
1405 if (tcp_rcv_state_process(sk, skb)) {
1412 tcp_v4_send_reset(rsk, skb);
1415 /* Be careful here. If this function gets more complicated and
1416 * gcc suffers from register pressure on the x86, sk (in %ebx)
1417 * might be destroyed here. This current version compiles correctly,
1418 * but you have been warned.
1423 TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_CSUMERRORS);
1424 TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_INERRS);
1427 EXPORT_SYMBOL(tcp_v4_do_rcv);
1429 void tcp_v4_early_demux(struct sk_buff *skb)
1431 const struct iphdr *iph;
1432 const struct tcphdr *th;
1435 if (skb->pkt_type != PACKET_HOST)
1438 if (!pskb_may_pull(skb, skb_transport_offset(skb) + sizeof(struct tcphdr)))
1444 if (th->doff < sizeof(struct tcphdr) / 4)
1447 sk = __inet_lookup_established(dev_net(skb->dev), &tcp_hashinfo,
1448 iph->saddr, th->source,
1449 iph->daddr, ntohs(th->dest),
1453 skb->destructor = sock_edemux;
1454 if (sk_fullsock(sk)) {
1455 struct dst_entry *dst = READ_ONCE(sk->sk_rx_dst);
1458 dst = dst_check(dst, 0);
1460 inet_sk(sk)->rx_dst_ifindex == skb->skb_iif)
1461 skb_dst_set_noref(skb, dst);
1466 /* Packet is added to VJ-style prequeue for processing in process
1467 * context, if a reader task is waiting. Apparently, this exciting
1468 * idea (VJ's mail "Re: query about TCP header on tcp-ip" of 07 Sep 93)
1469 * failed somewhere. Latency? Burstiness? Well, at least now we will
1470 * see, why it failed. 8)8) --ANK
1473 bool tcp_prequeue(struct sock *sk, struct sk_buff *skb)
1475 struct tcp_sock *tp = tcp_sk(sk);
1477 if (sysctl_tcp_low_latency || !tp->ucopy.task)
1480 if (skb->len <= tcp_hdrlen(skb) &&
1481 skb_queue_len(&tp->ucopy.prequeue) == 0)
1484 /* Before escaping RCU protected region, we need to take care of skb
1485 * dst. Prequeue is only enabled for established sockets.
1486 * For such sockets, we might need the skb dst only to set sk->sk_rx_dst
1487 * Instead of doing full sk_rx_dst validity here, let's perform
1488 * an optimistic check.
1490 if (likely(sk->sk_rx_dst))
1495 __skb_queue_tail(&tp->ucopy.prequeue, skb);
1496 tp->ucopy.memory += skb->truesize;
1497 if (tp->ucopy.memory > sk->sk_rcvbuf) {
1498 struct sk_buff *skb1;
1500 BUG_ON(sock_owned_by_user(sk));
1502 while ((skb1 = __skb_dequeue(&tp->ucopy.prequeue)) != NULL) {
1503 sk_backlog_rcv(sk, skb1);
1504 NET_INC_STATS_BH(sock_net(sk),
1505 LINUX_MIB_TCPPREQUEUEDROPPED);
1508 tp->ucopy.memory = 0;
1509 } else if (skb_queue_len(&tp->ucopy.prequeue) == 1) {
1510 wake_up_interruptible_sync_poll(sk_sleep(sk),
1511 POLLIN | POLLRDNORM | POLLRDBAND);
1512 if (!inet_csk_ack_scheduled(sk))
1513 inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK,
1514 (3 * tcp_rto_min(sk)) / 4,
1519 EXPORT_SYMBOL(tcp_prequeue);
1525 int tcp_v4_rcv(struct sk_buff *skb)
1527 const struct iphdr *iph;
1528 const struct tcphdr *th;
1531 struct net *net = dev_net(skb->dev);
1533 if (skb->pkt_type != PACKET_HOST)
1536 /* Count it even if it's bad */
1537 TCP_INC_STATS_BH(net, TCP_MIB_INSEGS);
1539 if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
1544 if (th->doff < sizeof(struct tcphdr) / 4)
1546 if (!pskb_may_pull(skb, th->doff * 4))
1549 /* An explanation is required here, I think.
1550 * Packet length and doff are validated by header prediction,
1551 * provided case of th->doff==0 is eliminated.
1552 * So, we defer the checks. */
1554 if (skb_checksum_init(skb, IPPROTO_TCP, inet_compute_pseudo))
1559 /* This is tricky : We move IPCB at its correct location into TCP_SKB_CB()
1560 * barrier() makes sure compiler wont play fool^Waliasing games.
1562 memmove(&TCP_SKB_CB(skb)->header.h4, IPCB(skb),
1563 sizeof(struct inet_skb_parm));
1566 TCP_SKB_CB(skb)->seq = ntohl(th->seq);
1567 TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
1568 skb->len - th->doff * 4);
1569 TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
1570 TCP_SKB_CB(skb)->tcp_flags = tcp_flag_byte(th);
1571 TCP_SKB_CB(skb)->tcp_tw_isn = 0;
1572 TCP_SKB_CB(skb)->ip_dsfield = ipv4_get_dsfield(iph);
1573 TCP_SKB_CB(skb)->sacked = 0;
1576 sk = __inet_lookup_skb(&tcp_hashinfo, skb, th->source, th->dest);
1581 if (sk->sk_state == TCP_TIME_WAIT)
1584 if (sk->sk_state == TCP_NEW_SYN_RECV) {
1585 struct request_sock *req = inet_reqsk(sk);
1586 struct sock *nsk = NULL;
1588 sk = req->rsk_listener;
1589 if (tcp_v4_inbound_md5_hash(sk, skb))
1590 goto discard_and_relse;
1591 if (likely(sk->sk_state == TCP_LISTEN)) {
1592 nsk = tcp_check_req(sk, skb, req, false);
1594 inet_csk_reqsk_queue_drop_and_put(sk, req);
1604 } else if (tcp_child_process(sk, nsk, skb)) {
1605 tcp_v4_send_reset(nsk, skb);
1611 if (unlikely(iph->ttl < inet_sk(sk)->min_ttl)) {
1612 NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP);
1613 goto discard_and_relse;
1616 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
1617 goto discard_and_relse;
1619 if (tcp_v4_inbound_md5_hash(sk, skb))
1620 goto discard_and_relse;
1624 if (sk_filter(sk, skb))
1625 goto discard_and_relse;
1629 if (sk->sk_state == TCP_LISTEN) {
1630 ret = tcp_v4_do_rcv(sk, skb);
1631 goto put_and_return;
1634 sk_incoming_cpu_update(sk);
1636 bh_lock_sock_nested(sk);
1637 tcp_sk(sk)->segs_in += max_t(u16, 1, skb_shinfo(skb)->gso_segs);
1639 if (!sock_owned_by_user(sk)) {
1640 if (!tcp_prequeue(sk, skb))
1641 ret = tcp_v4_do_rcv(sk, skb);
1642 } else if (unlikely(sk_add_backlog(sk, skb,
1643 sk->sk_rcvbuf + sk->sk_sndbuf))) {
1645 NET_INC_STATS_BH(net, LINUX_MIB_TCPBACKLOGDROP);
1646 goto discard_and_relse;
1656 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
1659 if (tcp_checksum_complete(skb)) {
1661 TCP_INC_STATS_BH(net, TCP_MIB_CSUMERRORS);
1663 TCP_INC_STATS_BH(net, TCP_MIB_INERRS);
1665 tcp_v4_send_reset(NULL, skb);
1669 /* Discard frame. */
1678 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
1679 inet_twsk_put(inet_twsk(sk));
1683 if (tcp_checksum_complete(skb)) {
1684 inet_twsk_put(inet_twsk(sk));
1687 switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) {
1689 struct sock *sk2 = inet_lookup_listener(dev_net(skb->dev),
1691 iph->saddr, th->source,
1692 iph->daddr, th->dest,
1695 inet_twsk_deschedule_put(inet_twsk(sk));
1699 /* Fall through to ACK */
1702 tcp_v4_timewait_ack(sk, skb);
1706 case TCP_TW_SUCCESS:;
1711 static struct timewait_sock_ops tcp_timewait_sock_ops = {
1712 .twsk_obj_size = sizeof(struct tcp_timewait_sock),
1713 .twsk_unique = tcp_twsk_unique,
1714 .twsk_destructor= tcp_twsk_destructor,
1717 void inet_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb)
1719 struct dst_entry *dst = skb_dst(skb);
1723 sk->sk_rx_dst = dst;
1724 inet_sk(sk)->rx_dst_ifindex = skb->skb_iif;
1727 EXPORT_SYMBOL(inet_sk_rx_dst_set);
1729 const struct inet_connection_sock_af_ops ipv4_specific = {
1730 .queue_xmit = ip_queue_xmit,
1731 .send_check = tcp_v4_send_check,
1732 .rebuild_header = inet_sk_rebuild_header,
1733 .sk_rx_dst_set = inet_sk_rx_dst_set,
1734 .conn_request = tcp_v4_conn_request,
1735 .syn_recv_sock = tcp_v4_syn_recv_sock,
1736 .net_header_len = sizeof(struct iphdr),
1737 .setsockopt = ip_setsockopt,
1738 .getsockopt = ip_getsockopt,
1739 .addr2sockaddr = inet_csk_addr2sockaddr,
1740 .sockaddr_len = sizeof(struct sockaddr_in),
1741 .bind_conflict = inet_csk_bind_conflict,
1742 #ifdef CONFIG_COMPAT
1743 .compat_setsockopt = compat_ip_setsockopt,
1744 .compat_getsockopt = compat_ip_getsockopt,
1746 .mtu_reduced = tcp_v4_mtu_reduced,
1748 EXPORT_SYMBOL(ipv4_specific);
1750 #ifdef CONFIG_TCP_MD5SIG
1751 static const struct tcp_sock_af_ops tcp_sock_ipv4_specific = {
1752 .md5_lookup = tcp_v4_md5_lookup,
1753 .calc_md5_hash = tcp_v4_md5_hash_skb,
1754 .md5_parse = tcp_v4_parse_md5_keys,
1758 /* NOTE: A lot of things set to zero explicitly by call to
1759 * sk_alloc() so need not be done here.
1761 static int tcp_v4_init_sock(struct sock *sk)
1763 struct inet_connection_sock *icsk = inet_csk(sk);
1767 icsk->icsk_af_ops = &ipv4_specific;
1769 #ifdef CONFIG_TCP_MD5SIG
1770 tcp_sk(sk)->af_specific = &tcp_sock_ipv4_specific;
1776 void tcp_v4_destroy_sock(struct sock *sk)
1778 struct tcp_sock *tp = tcp_sk(sk);
1780 tcp_clear_xmit_timers(sk);
1782 tcp_cleanup_congestion_control(sk);
1784 /* Cleanup up the write buffer. */
1785 tcp_write_queue_purge(sk);
1787 /* Cleans up our, hopefully empty, out_of_order_queue. */
1788 __skb_queue_purge(&tp->out_of_order_queue);
1790 #ifdef CONFIG_TCP_MD5SIG
1791 /* Clean up the MD5 key list, if any */
1792 if (tp->md5sig_info) {
1793 tcp_clear_md5_list(sk);
1794 kfree_rcu(tp->md5sig_info, rcu);
1795 tp->md5sig_info = NULL;
1799 /* Clean prequeue, it must be empty really */
1800 __skb_queue_purge(&tp->ucopy.prequeue);
1802 /* Clean up a referenced TCP bind bucket. */
1803 if (inet_csk(sk)->icsk_bind_hash)
1806 BUG_ON(tp->fastopen_rsk);
1808 /* If socket is aborted during connect operation */
1809 tcp_free_fastopen_req(tp);
1810 tcp_saved_syn_free(tp);
1812 sk_sockets_allocated_dec(sk);
1813 sock_release_memcg(sk);
1815 EXPORT_SYMBOL(tcp_v4_destroy_sock);
1817 #ifdef CONFIG_PROC_FS
1818 /* Proc filesystem TCP sock list dumping. */
1821 * Get next listener socket follow cur. If cur is NULL, get first socket
1822 * starting from bucket given in st->bucket; when st->bucket is zero the
1823 * very first socket in the hash table is returned.
1825 static void *listening_get_next(struct seq_file *seq, void *cur)
1827 struct inet_connection_sock *icsk;
1828 struct hlist_nulls_node *node;
1829 struct sock *sk = cur;
1830 struct inet_listen_hashbucket *ilb;
1831 struct tcp_iter_state *st = seq->private;
1832 struct net *net = seq_file_net(seq);
1835 ilb = &tcp_hashinfo.listening_hash[st->bucket];
1836 spin_lock_bh(&ilb->lock);
1837 sk = sk_nulls_head(&ilb->head);
1841 ilb = &tcp_hashinfo.listening_hash[st->bucket];
1845 sk = sk_nulls_next(sk);
1847 sk_nulls_for_each_from(sk, node) {
1848 if (!net_eq(sock_net(sk), net))
1850 if (sk->sk_family == st->family) {
1854 icsk = inet_csk(sk);
1856 spin_unlock_bh(&ilb->lock);
1858 if (++st->bucket < INET_LHTABLE_SIZE) {
1859 ilb = &tcp_hashinfo.listening_hash[st->bucket];
1860 spin_lock_bh(&ilb->lock);
1861 sk = sk_nulls_head(&ilb->head);
1869 static void *listening_get_idx(struct seq_file *seq, loff_t *pos)
1871 struct tcp_iter_state *st = seq->private;
1876 rc = listening_get_next(seq, NULL);
1878 while (rc && *pos) {
1879 rc = listening_get_next(seq, rc);
1885 static inline bool empty_bucket(const struct tcp_iter_state *st)
1887 return hlist_nulls_empty(&tcp_hashinfo.ehash[st->bucket].chain);
1891 * Get first established socket starting from bucket given in st->bucket.
1892 * If st->bucket is zero, the very first socket in the hash is returned.
1894 static void *established_get_first(struct seq_file *seq)
1896 struct tcp_iter_state *st = seq->private;
1897 struct net *net = seq_file_net(seq);
1901 for (; st->bucket <= tcp_hashinfo.ehash_mask; ++st->bucket) {
1903 struct hlist_nulls_node *node;
1904 spinlock_t *lock = inet_ehash_lockp(&tcp_hashinfo, st->bucket);
1906 /* Lockless fast path for the common case of empty buckets */
1907 if (empty_bucket(st))
1911 sk_nulls_for_each(sk, node, &tcp_hashinfo.ehash[st->bucket].chain) {
1912 if (sk->sk_family != st->family ||
1913 !net_eq(sock_net(sk), net)) {
1919 spin_unlock_bh(lock);
1925 static void *established_get_next(struct seq_file *seq, void *cur)
1927 struct sock *sk = cur;
1928 struct hlist_nulls_node *node;
1929 struct tcp_iter_state *st = seq->private;
1930 struct net *net = seq_file_net(seq);
1935 sk = sk_nulls_next(sk);
1937 sk_nulls_for_each_from(sk, node) {
1938 if (sk->sk_family == st->family && net_eq(sock_net(sk), net))
1942 spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
1944 return established_get_first(seq);
1947 static void *established_get_idx(struct seq_file *seq, loff_t pos)
1949 struct tcp_iter_state *st = seq->private;
1953 rc = established_get_first(seq);
1956 rc = established_get_next(seq, rc);
1962 static void *tcp_get_idx(struct seq_file *seq, loff_t pos)
1965 struct tcp_iter_state *st = seq->private;
1967 st->state = TCP_SEQ_STATE_LISTENING;
1968 rc = listening_get_idx(seq, &pos);
1971 st->state = TCP_SEQ_STATE_ESTABLISHED;
1972 rc = established_get_idx(seq, pos);
1978 static void *tcp_seek_last_pos(struct seq_file *seq)
1980 struct tcp_iter_state *st = seq->private;
1981 int offset = st->offset;
1982 int orig_num = st->num;
1985 switch (st->state) {
1986 case TCP_SEQ_STATE_LISTENING:
1987 if (st->bucket >= INET_LHTABLE_SIZE)
1989 st->state = TCP_SEQ_STATE_LISTENING;
1990 rc = listening_get_next(seq, NULL);
1991 while (offset-- && rc)
1992 rc = listening_get_next(seq, rc);
1996 st->state = TCP_SEQ_STATE_ESTABLISHED;
1998 case TCP_SEQ_STATE_ESTABLISHED:
1999 if (st->bucket > tcp_hashinfo.ehash_mask)
2001 rc = established_get_first(seq);
2002 while (offset-- && rc)
2003 rc = established_get_next(seq, rc);
2011 static void *tcp_seq_start(struct seq_file *seq, loff_t *pos)
2013 struct tcp_iter_state *st = seq->private;
2016 if (*pos && *pos == st->last_pos) {
2017 rc = tcp_seek_last_pos(seq);
2022 st->state = TCP_SEQ_STATE_LISTENING;
2026 rc = *pos ? tcp_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
2029 st->last_pos = *pos;
2033 static void *tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2035 struct tcp_iter_state *st = seq->private;
2038 if (v == SEQ_START_TOKEN) {
2039 rc = tcp_get_idx(seq, 0);
2043 switch (st->state) {
2044 case TCP_SEQ_STATE_LISTENING:
2045 rc = listening_get_next(seq, v);
2047 st->state = TCP_SEQ_STATE_ESTABLISHED;
2050 rc = established_get_first(seq);
2053 case TCP_SEQ_STATE_ESTABLISHED:
2054 rc = established_get_next(seq, v);
2059 st->last_pos = *pos;
2063 static void tcp_seq_stop(struct seq_file *seq, void *v)
2065 struct tcp_iter_state *st = seq->private;
2067 switch (st->state) {
2068 case TCP_SEQ_STATE_LISTENING:
2069 if (v != SEQ_START_TOKEN)
2070 spin_unlock_bh(&tcp_hashinfo.listening_hash[st->bucket].lock);
2072 case TCP_SEQ_STATE_ESTABLISHED:
2074 spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
2079 int tcp_seq_open(struct inode *inode, struct file *file)
2081 struct tcp_seq_afinfo *afinfo = PDE_DATA(inode);
2082 struct tcp_iter_state *s;
2085 err = seq_open_net(inode, file, &afinfo->seq_ops,
2086 sizeof(struct tcp_iter_state));
2090 s = ((struct seq_file *)file->private_data)->private;
2091 s->family = afinfo->family;
2095 EXPORT_SYMBOL(tcp_seq_open);
2097 int tcp_proc_register(struct net *net, struct tcp_seq_afinfo *afinfo)
2100 struct proc_dir_entry *p;
2102 afinfo->seq_ops.start = tcp_seq_start;
2103 afinfo->seq_ops.next = tcp_seq_next;
2104 afinfo->seq_ops.stop = tcp_seq_stop;
2106 p = proc_create_data(afinfo->name, S_IRUGO, net->proc_net,
2107 afinfo->seq_fops, afinfo);
2112 EXPORT_SYMBOL(tcp_proc_register);
2114 void tcp_proc_unregister(struct net *net, struct tcp_seq_afinfo *afinfo)
2116 remove_proc_entry(afinfo->name, net->proc_net);
2118 EXPORT_SYMBOL(tcp_proc_unregister);
2120 static void get_openreq4(const struct request_sock *req,
2121 struct seq_file *f, int i)
2123 const struct inet_request_sock *ireq = inet_rsk(req);
2124 long delta = req->rsk_timer.expires - jiffies;
2126 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2127 " %02X %08X:%08X %02X:%08lX %08X %5u %8d %u %d %pK",
2132 ntohs(ireq->ir_rmt_port),
2134 0, 0, /* could print option size, but that is af dependent. */
2135 1, /* timers active (only the expire timer) */
2136 jiffies_delta_to_clock_t(delta),
2138 from_kuid_munged(seq_user_ns(f),
2139 sock_i_uid(req->rsk_listener)),
2140 0, /* non standard timer */
2141 0, /* open_requests have no inode */
2146 static void get_tcp4_sock(struct sock *sk, struct seq_file *f, int i)
2149 unsigned long timer_expires;
2150 const struct tcp_sock *tp = tcp_sk(sk);
2151 const struct inet_connection_sock *icsk = inet_csk(sk);
2152 const struct inet_sock *inet = inet_sk(sk);
2153 const struct fastopen_queue *fastopenq = &icsk->icsk_accept_queue.fastopenq;
2154 __be32 dest = inet->inet_daddr;
2155 __be32 src = inet->inet_rcv_saddr;
2156 __u16 destp = ntohs(inet->inet_dport);
2157 __u16 srcp = ntohs(inet->inet_sport);
2160 if (icsk->icsk_pending == ICSK_TIME_RETRANS ||
2161 icsk->icsk_pending == ICSK_TIME_EARLY_RETRANS ||
2162 icsk->icsk_pending == ICSK_TIME_LOSS_PROBE) {
2164 timer_expires = icsk->icsk_timeout;
2165 } else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
2167 timer_expires = icsk->icsk_timeout;
2168 } else if (timer_pending(&sk->sk_timer)) {
2170 timer_expires = sk->sk_timer.expires;
2173 timer_expires = jiffies;
2176 if (sk->sk_state == TCP_LISTEN)
2177 rx_queue = sk->sk_ack_backlog;
2180 * because we dont lock socket, we might find a transient negative value
2182 rx_queue = max_t(int, tp->rcv_nxt - tp->copied_seq, 0);
2184 seq_printf(f, "%4d: %08X:%04X %08X:%04X %02X %08X:%08X %02X:%08lX "
2185 "%08X %5u %8d %lu %d %pK %lu %lu %u %u %d",
2186 i, src, srcp, dest, destp, sk->sk_state,
2187 tp->write_seq - tp->snd_una,
2190 jiffies_delta_to_clock_t(timer_expires - jiffies),
2191 icsk->icsk_retransmits,
2192 from_kuid_munged(seq_user_ns(f), sock_i_uid(sk)),
2193 icsk->icsk_probes_out,
2195 atomic_read(&sk->sk_refcnt), sk,
2196 jiffies_to_clock_t(icsk->icsk_rto),
2197 jiffies_to_clock_t(icsk->icsk_ack.ato),
2198 (icsk->icsk_ack.quick << 1) | icsk->icsk_ack.pingpong,
2200 sk->sk_state == TCP_LISTEN ?
2201 (fastopenq ? fastopenq->max_qlen : 0) :
2202 (tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh));
2205 static void get_timewait4_sock(const struct inet_timewait_sock *tw,
2206 struct seq_file *f, int i)
2208 long delta = tw->tw_timer.expires - jiffies;
2212 dest = tw->tw_daddr;
2213 src = tw->tw_rcv_saddr;
2214 destp = ntohs(tw->tw_dport);
2215 srcp = ntohs(tw->tw_sport);
2217 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2218 " %02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK",
2219 i, src, srcp, dest, destp, tw->tw_substate, 0, 0,
2220 3, jiffies_delta_to_clock_t(delta), 0, 0, 0, 0,
2221 atomic_read(&tw->tw_refcnt), tw);
2226 static int tcp4_seq_show(struct seq_file *seq, void *v)
2228 struct tcp_iter_state *st;
2229 struct sock *sk = v;
2231 seq_setwidth(seq, TMPSZ - 1);
2232 if (v == SEQ_START_TOKEN) {
2233 seq_puts(seq, " sl local_address rem_address st tx_queue "
2234 "rx_queue tr tm->when retrnsmt uid timeout "
2240 if (sk->sk_state == TCP_TIME_WAIT)
2241 get_timewait4_sock(v, seq, st->num);
2242 else if (sk->sk_state == TCP_NEW_SYN_RECV)
2243 get_openreq4(v, seq, st->num);
2245 get_tcp4_sock(v, seq, st->num);
2251 static const struct file_operations tcp_afinfo_seq_fops = {
2252 .owner = THIS_MODULE,
2253 .open = tcp_seq_open,
2255 .llseek = seq_lseek,
2256 .release = seq_release_net
2259 static struct tcp_seq_afinfo tcp4_seq_afinfo = {
2262 .seq_fops = &tcp_afinfo_seq_fops,
2264 .show = tcp4_seq_show,
2268 static int __net_init tcp4_proc_init_net(struct net *net)
2270 return tcp_proc_register(net, &tcp4_seq_afinfo);
2273 static void __net_exit tcp4_proc_exit_net(struct net *net)
2275 tcp_proc_unregister(net, &tcp4_seq_afinfo);
2278 static struct pernet_operations tcp4_net_ops = {
2279 .init = tcp4_proc_init_net,
2280 .exit = tcp4_proc_exit_net,
2283 int __init tcp4_proc_init(void)
2285 return register_pernet_subsys(&tcp4_net_ops);
2288 void tcp4_proc_exit(void)
2290 unregister_pernet_subsys(&tcp4_net_ops);
2292 #endif /* CONFIG_PROC_FS */
2294 struct proto tcp_prot = {
2296 .owner = THIS_MODULE,
2298 .connect = tcp_v4_connect,
2299 .disconnect = tcp_disconnect,
2300 .accept = inet_csk_accept,
2302 .init = tcp_v4_init_sock,
2303 .destroy = tcp_v4_destroy_sock,
2304 .shutdown = tcp_shutdown,
2305 .setsockopt = tcp_setsockopt,
2306 .getsockopt = tcp_getsockopt,
2307 .recvmsg = tcp_recvmsg,
2308 .sendmsg = tcp_sendmsg,
2309 .sendpage = tcp_sendpage,
2310 .backlog_rcv = tcp_v4_do_rcv,
2311 .release_cb = tcp_release_cb,
2313 .unhash = inet_unhash,
2314 .get_port = inet_csk_get_port,
2315 .enter_memory_pressure = tcp_enter_memory_pressure,
2316 .stream_memory_free = tcp_stream_memory_free,
2317 .sockets_allocated = &tcp_sockets_allocated,
2318 .orphan_count = &tcp_orphan_count,
2319 .memory_allocated = &tcp_memory_allocated,
2320 .memory_pressure = &tcp_memory_pressure,
2321 .sysctl_mem = sysctl_tcp_mem,
2322 .sysctl_wmem = sysctl_tcp_wmem,
2323 .sysctl_rmem = sysctl_tcp_rmem,
2324 .max_header = MAX_TCP_HEADER,
2325 .obj_size = sizeof(struct tcp_sock),
2326 .slab_flags = SLAB_DESTROY_BY_RCU,
2327 .twsk_prot = &tcp_timewait_sock_ops,
2328 .rsk_prot = &tcp_request_sock_ops,
2329 .h.hashinfo = &tcp_hashinfo,
2330 .no_autobind = true,
2331 #ifdef CONFIG_COMPAT
2332 .compat_setsockopt = compat_tcp_setsockopt,
2333 .compat_getsockopt = compat_tcp_getsockopt,
2335 #ifdef CONFIG_MEMCG_KMEM
2336 .init_cgroup = tcp_init_cgroup,
2337 .destroy_cgroup = tcp_destroy_cgroup,
2338 .proto_cgroup = tcp_proto_cgroup,
2341 EXPORT_SYMBOL(tcp_prot);
2343 static void __net_exit tcp_sk_exit(struct net *net)
2347 for_each_possible_cpu(cpu)
2348 inet_ctl_sock_destroy(*per_cpu_ptr(net->ipv4.tcp_sk, cpu));
2349 free_percpu(net->ipv4.tcp_sk);
2352 static int __net_init tcp_sk_init(struct net *net)
2356 net->ipv4.tcp_sk = alloc_percpu(struct sock *);
2357 if (!net->ipv4.tcp_sk)
2360 for_each_possible_cpu(cpu) {
2363 res = inet_ctl_sock_create(&sk, PF_INET, SOCK_RAW,
2367 *per_cpu_ptr(net->ipv4.tcp_sk, cpu) = sk;
2370 net->ipv4.sysctl_tcp_ecn = 2;
2371 net->ipv4.sysctl_tcp_ecn_fallback = 1;
2373 net->ipv4.sysctl_tcp_base_mss = TCP_BASE_MSS;
2374 net->ipv4.sysctl_tcp_probe_threshold = TCP_PROBE_THRESHOLD;
2375 net->ipv4.sysctl_tcp_probe_interval = TCP_PROBE_INTERVAL;
2384 static void __net_exit tcp_sk_exit_batch(struct list_head *net_exit_list)
2386 inet_twsk_purge(&tcp_hashinfo, &tcp_death_row, AF_INET);
2389 static struct pernet_operations __net_initdata tcp_sk_ops = {
2390 .init = tcp_sk_init,
2391 .exit = tcp_sk_exit,
2392 .exit_batch = tcp_sk_exit_batch,
2395 void __init tcp_v4_init(void)
2397 inet_hashinfo_init(&tcp_hashinfo);
2398 if (register_pernet_subsys(&tcp_sk_ops))
2399 panic("Failed to create the TCP control socket.\n");