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);
330 * Still in SYN_RECV, just remove it silently.
331 * There is no good way to pass the error to the newly
332 * created socket, and POSIX does not want network
333 * errors returned from accept().
335 NET_INC_STATS_BH(net, LINUX_MIB_LISTENDROPS);
336 inet_csk_reqsk_queue_drop(req->rsk_listener, req);
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,
825 struct tcp_fastopen_cookie *foc,
828 const struct inet_request_sock *ireq = inet_rsk(req);
833 /* First, grab a route. */
834 if (!dst && (dst = inet_csk_route_req(sk, &fl4, req)) == NULL)
837 skb = tcp_make_synack(sk, dst, req, foc, attach_req);
840 __tcp_v4_send_check(skb, ireq->ir_loc_addr, ireq->ir_rmt_addr);
842 skb_set_queue_mapping(skb, queue_mapping);
843 err = ip_build_and_send_pkt(skb, sk, ireq->ir_loc_addr,
846 err = net_xmit_eval(err);
853 * IPv4 request_sock destructor.
855 static void tcp_v4_reqsk_destructor(struct request_sock *req)
857 kfree(inet_rsk(req)->opt);
861 #ifdef CONFIG_TCP_MD5SIG
863 * RFC2385 MD5 checksumming requires a mapping of
864 * IP address->MD5 Key.
865 * We need to maintain these in the sk structure.
868 /* Find the Key structure for an address. */
869 struct tcp_md5sig_key *tcp_md5_do_lookup(const struct sock *sk,
870 const union tcp_md5_addr *addr,
873 const struct tcp_sock *tp = tcp_sk(sk);
874 struct tcp_md5sig_key *key;
875 unsigned int size = sizeof(struct in_addr);
876 const struct tcp_md5sig_info *md5sig;
878 /* caller either holds rcu_read_lock() or socket lock */
879 md5sig = rcu_dereference_check(tp->md5sig_info,
880 sock_owned_by_user(sk) ||
881 lockdep_is_held((spinlock_t *)&sk->sk_lock.slock));
884 #if IS_ENABLED(CONFIG_IPV6)
885 if (family == AF_INET6)
886 size = sizeof(struct in6_addr);
888 hlist_for_each_entry_rcu(key, &md5sig->head, node) {
889 if (key->family != family)
891 if (!memcmp(&key->addr, addr, size))
896 EXPORT_SYMBOL(tcp_md5_do_lookup);
898 struct tcp_md5sig_key *tcp_v4_md5_lookup(const struct sock *sk,
899 const struct sock *addr_sk)
901 const union tcp_md5_addr *addr;
903 addr = (const union tcp_md5_addr *)&addr_sk->sk_daddr;
904 return tcp_md5_do_lookup(sk, addr, AF_INET);
906 EXPORT_SYMBOL(tcp_v4_md5_lookup);
908 /* This can be called on a newly created socket, from other files */
909 int tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr,
910 int family, const u8 *newkey, u8 newkeylen, gfp_t gfp)
912 /* Add Key to the list */
913 struct tcp_md5sig_key *key;
914 struct tcp_sock *tp = tcp_sk(sk);
915 struct tcp_md5sig_info *md5sig;
917 key = tcp_md5_do_lookup(sk, addr, family);
919 /* Pre-existing entry - just update that one. */
920 memcpy(key->key, newkey, newkeylen);
921 key->keylen = newkeylen;
925 md5sig = rcu_dereference_protected(tp->md5sig_info,
926 sock_owned_by_user(sk));
928 md5sig = kmalloc(sizeof(*md5sig), gfp);
932 sk_nocaps_add(sk, NETIF_F_GSO_MASK);
933 INIT_HLIST_HEAD(&md5sig->head);
934 rcu_assign_pointer(tp->md5sig_info, md5sig);
937 key = sock_kmalloc(sk, sizeof(*key), gfp);
940 if (!tcp_alloc_md5sig_pool()) {
941 sock_kfree_s(sk, key, sizeof(*key));
945 memcpy(key->key, newkey, newkeylen);
946 key->keylen = newkeylen;
947 key->family = family;
948 memcpy(&key->addr, addr,
949 (family == AF_INET6) ? sizeof(struct in6_addr) :
950 sizeof(struct in_addr));
951 hlist_add_head_rcu(&key->node, &md5sig->head);
954 EXPORT_SYMBOL(tcp_md5_do_add);
956 int tcp_md5_do_del(struct sock *sk, const union tcp_md5_addr *addr, int family)
958 struct tcp_md5sig_key *key;
960 key = tcp_md5_do_lookup(sk, addr, family);
963 hlist_del_rcu(&key->node);
964 atomic_sub(sizeof(*key), &sk->sk_omem_alloc);
968 EXPORT_SYMBOL(tcp_md5_do_del);
970 static void tcp_clear_md5_list(struct sock *sk)
972 struct tcp_sock *tp = tcp_sk(sk);
973 struct tcp_md5sig_key *key;
974 struct hlist_node *n;
975 struct tcp_md5sig_info *md5sig;
977 md5sig = rcu_dereference_protected(tp->md5sig_info, 1);
979 hlist_for_each_entry_safe(key, n, &md5sig->head, node) {
980 hlist_del_rcu(&key->node);
981 atomic_sub(sizeof(*key), &sk->sk_omem_alloc);
986 static int tcp_v4_parse_md5_keys(struct sock *sk, char __user *optval,
989 struct tcp_md5sig cmd;
990 struct sockaddr_in *sin = (struct sockaddr_in *)&cmd.tcpm_addr;
992 if (optlen < sizeof(cmd))
995 if (copy_from_user(&cmd, optval, sizeof(cmd)))
998 if (sin->sin_family != AF_INET)
1001 if (!cmd.tcpm_keylen)
1002 return tcp_md5_do_del(sk, (union tcp_md5_addr *)&sin->sin_addr.s_addr,
1005 if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN)
1008 return tcp_md5_do_add(sk, (union tcp_md5_addr *)&sin->sin_addr.s_addr,
1009 AF_INET, cmd.tcpm_key, cmd.tcpm_keylen,
1013 static int tcp_v4_md5_hash_pseudoheader(struct tcp_md5sig_pool *hp,
1014 __be32 daddr, __be32 saddr, int nbytes)
1016 struct tcp4_pseudohdr *bp;
1017 struct scatterlist sg;
1019 bp = &hp->md5_blk.ip4;
1022 * 1. the TCP pseudo-header (in the order: source IP address,
1023 * destination IP address, zero-padded protocol number, and
1029 bp->protocol = IPPROTO_TCP;
1030 bp->len = cpu_to_be16(nbytes);
1032 sg_init_one(&sg, bp, sizeof(*bp));
1033 return crypto_hash_update(&hp->md5_desc, &sg, sizeof(*bp));
1036 static int tcp_v4_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key,
1037 __be32 daddr, __be32 saddr, const struct tcphdr *th)
1039 struct tcp_md5sig_pool *hp;
1040 struct hash_desc *desc;
1042 hp = tcp_get_md5sig_pool();
1044 goto clear_hash_noput;
1045 desc = &hp->md5_desc;
1047 if (crypto_hash_init(desc))
1049 if (tcp_v4_md5_hash_pseudoheader(hp, daddr, saddr, th->doff << 2))
1051 if (tcp_md5_hash_header(hp, th))
1053 if (tcp_md5_hash_key(hp, key))
1055 if (crypto_hash_final(desc, md5_hash))
1058 tcp_put_md5sig_pool();
1062 tcp_put_md5sig_pool();
1064 memset(md5_hash, 0, 16);
1068 int tcp_v4_md5_hash_skb(char *md5_hash, const struct tcp_md5sig_key *key,
1069 const struct sock *sk,
1070 const struct sk_buff *skb)
1072 struct tcp_md5sig_pool *hp;
1073 struct hash_desc *desc;
1074 const struct tcphdr *th = tcp_hdr(skb);
1075 __be32 saddr, daddr;
1077 if (sk) { /* valid for establish/request sockets */
1078 saddr = sk->sk_rcv_saddr;
1079 daddr = sk->sk_daddr;
1081 const struct iphdr *iph = ip_hdr(skb);
1086 hp = tcp_get_md5sig_pool();
1088 goto clear_hash_noput;
1089 desc = &hp->md5_desc;
1091 if (crypto_hash_init(desc))
1094 if (tcp_v4_md5_hash_pseudoheader(hp, daddr, saddr, skb->len))
1096 if (tcp_md5_hash_header(hp, th))
1098 if (tcp_md5_hash_skb_data(hp, skb, th->doff << 2))
1100 if (tcp_md5_hash_key(hp, key))
1102 if (crypto_hash_final(desc, md5_hash))
1105 tcp_put_md5sig_pool();
1109 tcp_put_md5sig_pool();
1111 memset(md5_hash, 0, 16);
1114 EXPORT_SYMBOL(tcp_v4_md5_hash_skb);
1118 /* Called with rcu_read_lock() */
1119 static bool tcp_v4_inbound_md5_hash(const struct sock *sk,
1120 const struct sk_buff *skb)
1122 #ifdef CONFIG_TCP_MD5SIG
1124 * This gets called for each TCP segment that arrives
1125 * so we want to be efficient.
1126 * We have 3 drop cases:
1127 * o No MD5 hash and one expected.
1128 * o MD5 hash and we're not expecting one.
1129 * o MD5 hash and its wrong.
1131 const __u8 *hash_location = NULL;
1132 struct tcp_md5sig_key *hash_expected;
1133 const struct iphdr *iph = ip_hdr(skb);
1134 const struct tcphdr *th = tcp_hdr(skb);
1136 unsigned char newhash[16];
1138 hash_expected = tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&iph->saddr,
1140 hash_location = tcp_parse_md5sig_option(th);
1142 /* We've parsed the options - do we have a hash? */
1143 if (!hash_expected && !hash_location)
1146 if (hash_expected && !hash_location) {
1147 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5NOTFOUND);
1151 if (!hash_expected && hash_location) {
1152 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5UNEXPECTED);
1156 /* Okay, so this is hash_expected and hash_location -
1157 * so we need to calculate the checksum.
1159 genhash = tcp_v4_md5_hash_skb(newhash,
1163 if (genhash || memcmp(hash_location, newhash, 16) != 0) {
1164 net_info_ratelimited("MD5 Hash failed for (%pI4, %d)->(%pI4, %d)%s\n",
1165 &iph->saddr, ntohs(th->source),
1166 &iph->daddr, ntohs(th->dest),
1167 genhash ? " tcp_v4_calc_md5_hash failed"
1176 static void tcp_v4_init_req(struct request_sock *req,
1177 const struct sock *sk_listener,
1178 struct sk_buff *skb)
1180 struct inet_request_sock *ireq = inet_rsk(req);
1182 sk_rcv_saddr_set(req_to_sk(req), ip_hdr(skb)->daddr);
1183 sk_daddr_set(req_to_sk(req), ip_hdr(skb)->saddr);
1184 ireq->no_srccheck = inet_sk(sk_listener)->transparent;
1185 ireq->opt = tcp_v4_save_options(skb);
1188 static struct dst_entry *tcp_v4_route_req(const struct sock *sk,
1190 const struct request_sock *req,
1193 struct dst_entry *dst = inet_csk_route_req(sk, &fl->u.ip4, req);
1196 if (fl->u.ip4.daddr == inet_rsk(req)->ir_rmt_addr)
1205 struct request_sock_ops tcp_request_sock_ops __read_mostly = {
1207 .obj_size = sizeof(struct tcp_request_sock),
1208 .rtx_syn_ack = tcp_rtx_synack,
1209 .send_ack = tcp_v4_reqsk_send_ack,
1210 .destructor = tcp_v4_reqsk_destructor,
1211 .send_reset = tcp_v4_send_reset,
1212 .syn_ack_timeout = tcp_syn_ack_timeout,
1215 static const struct tcp_request_sock_ops tcp_request_sock_ipv4_ops = {
1216 .mss_clamp = TCP_MSS_DEFAULT,
1217 #ifdef CONFIG_TCP_MD5SIG
1218 .req_md5_lookup = tcp_v4_md5_lookup,
1219 .calc_md5_hash = tcp_v4_md5_hash_skb,
1221 .init_req = tcp_v4_init_req,
1222 #ifdef CONFIG_SYN_COOKIES
1223 .cookie_init_seq = cookie_v4_init_sequence,
1225 .route_req = tcp_v4_route_req,
1226 .init_seq = tcp_v4_init_sequence,
1227 .send_synack = tcp_v4_send_synack,
1230 int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
1232 /* Never answer to SYNs send to broadcast or multicast */
1233 if (skb_rtable(skb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
1236 return tcp_conn_request(&tcp_request_sock_ops,
1237 &tcp_request_sock_ipv4_ops, sk, skb);
1240 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
1243 EXPORT_SYMBOL(tcp_v4_conn_request);
1247 * The three way handshake has completed - we got a valid synack -
1248 * now create the new socket.
1250 struct sock *tcp_v4_syn_recv_sock(const struct sock *sk, struct sk_buff *skb,
1251 struct request_sock *req,
1252 struct dst_entry *dst)
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 __inet_hash_nolisten(newsk, NULL);
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;
1575 sk = __inet_lookup_skb(&tcp_hashinfo, skb, th->source, th->dest);
1580 if (sk->sk_state == TCP_TIME_WAIT)
1583 if (sk->sk_state == TCP_NEW_SYN_RECV) {
1584 struct request_sock *req = inet_reqsk(sk);
1585 struct sock *nsk = NULL;
1587 sk = req->rsk_listener;
1588 if (tcp_v4_inbound_md5_hash(sk, skb))
1589 goto discard_and_relse;
1590 if (sk->sk_state == TCP_LISTEN)
1591 nsk = tcp_check_req(sk, skb, req, false);
1599 } else if (tcp_child_process(sk, nsk, skb)) {
1600 tcp_v4_send_reset(nsk, skb);
1606 if (unlikely(iph->ttl < inet_sk(sk)->min_ttl)) {
1607 NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP);
1608 goto discard_and_relse;
1611 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
1612 goto discard_and_relse;
1614 if (tcp_v4_inbound_md5_hash(sk, skb))
1615 goto discard_and_relse;
1619 if (sk_filter(sk, skb))
1620 goto discard_and_relse;
1624 if (sk->sk_state == TCP_LISTEN) {
1625 ret = tcp_v4_do_rcv(sk, skb);
1626 goto put_and_return;
1629 sk_incoming_cpu_update(sk);
1631 bh_lock_sock_nested(sk);
1632 tcp_sk(sk)->segs_in += max_t(u16, 1, skb_shinfo(skb)->gso_segs);
1634 if (!sock_owned_by_user(sk)) {
1635 if (!tcp_prequeue(sk, skb))
1636 ret = tcp_v4_do_rcv(sk, skb);
1637 } else if (unlikely(sk_add_backlog(sk, skb,
1638 sk->sk_rcvbuf + sk->sk_sndbuf))) {
1640 NET_INC_STATS_BH(net, LINUX_MIB_TCPBACKLOGDROP);
1641 goto discard_and_relse;
1651 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
1654 if (tcp_checksum_complete(skb)) {
1656 TCP_INC_STATS_BH(net, TCP_MIB_CSUMERRORS);
1658 TCP_INC_STATS_BH(net, TCP_MIB_INERRS);
1660 tcp_v4_send_reset(NULL, skb);
1664 /* Discard frame. */
1673 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
1674 inet_twsk_put(inet_twsk(sk));
1678 if (tcp_checksum_complete(skb)) {
1679 inet_twsk_put(inet_twsk(sk));
1682 switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) {
1684 struct sock *sk2 = inet_lookup_listener(dev_net(skb->dev),
1686 iph->saddr, th->source,
1687 iph->daddr, th->dest,
1690 inet_twsk_deschedule_put(inet_twsk(sk));
1694 /* Fall through to ACK */
1697 tcp_v4_timewait_ack(sk, skb);
1701 case TCP_TW_SUCCESS:;
1706 static struct timewait_sock_ops tcp_timewait_sock_ops = {
1707 .twsk_obj_size = sizeof(struct tcp_timewait_sock),
1708 .twsk_unique = tcp_twsk_unique,
1709 .twsk_destructor= tcp_twsk_destructor,
1712 void inet_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb)
1714 struct dst_entry *dst = skb_dst(skb);
1718 sk->sk_rx_dst = dst;
1719 inet_sk(sk)->rx_dst_ifindex = skb->skb_iif;
1722 EXPORT_SYMBOL(inet_sk_rx_dst_set);
1724 const struct inet_connection_sock_af_ops ipv4_specific = {
1725 .queue_xmit = ip_queue_xmit,
1726 .send_check = tcp_v4_send_check,
1727 .rebuild_header = inet_sk_rebuild_header,
1728 .sk_rx_dst_set = inet_sk_rx_dst_set,
1729 .conn_request = tcp_v4_conn_request,
1730 .syn_recv_sock = tcp_v4_syn_recv_sock,
1731 .net_header_len = sizeof(struct iphdr),
1732 .setsockopt = ip_setsockopt,
1733 .getsockopt = ip_getsockopt,
1734 .addr2sockaddr = inet_csk_addr2sockaddr,
1735 .sockaddr_len = sizeof(struct sockaddr_in),
1736 .bind_conflict = inet_csk_bind_conflict,
1737 #ifdef CONFIG_COMPAT
1738 .compat_setsockopt = compat_ip_setsockopt,
1739 .compat_getsockopt = compat_ip_getsockopt,
1741 .mtu_reduced = tcp_v4_mtu_reduced,
1743 EXPORT_SYMBOL(ipv4_specific);
1745 #ifdef CONFIG_TCP_MD5SIG
1746 static const struct tcp_sock_af_ops tcp_sock_ipv4_specific = {
1747 .md5_lookup = tcp_v4_md5_lookup,
1748 .calc_md5_hash = tcp_v4_md5_hash_skb,
1749 .md5_parse = tcp_v4_parse_md5_keys,
1753 /* NOTE: A lot of things set to zero explicitly by call to
1754 * sk_alloc() so need not be done here.
1756 static int tcp_v4_init_sock(struct sock *sk)
1758 struct inet_connection_sock *icsk = inet_csk(sk);
1762 icsk->icsk_af_ops = &ipv4_specific;
1764 #ifdef CONFIG_TCP_MD5SIG
1765 tcp_sk(sk)->af_specific = &tcp_sock_ipv4_specific;
1771 void tcp_v4_destroy_sock(struct sock *sk)
1773 struct tcp_sock *tp = tcp_sk(sk);
1775 tcp_clear_xmit_timers(sk);
1777 tcp_cleanup_congestion_control(sk);
1779 /* Cleanup up the write buffer. */
1780 tcp_write_queue_purge(sk);
1782 /* Cleans up our, hopefully empty, out_of_order_queue. */
1783 __skb_queue_purge(&tp->out_of_order_queue);
1785 #ifdef CONFIG_TCP_MD5SIG
1786 /* Clean up the MD5 key list, if any */
1787 if (tp->md5sig_info) {
1788 tcp_clear_md5_list(sk);
1789 kfree_rcu(tp->md5sig_info, rcu);
1790 tp->md5sig_info = NULL;
1794 /* Clean prequeue, it must be empty really */
1795 __skb_queue_purge(&tp->ucopy.prequeue);
1797 /* Clean up a referenced TCP bind bucket. */
1798 if (inet_csk(sk)->icsk_bind_hash)
1801 BUG_ON(tp->fastopen_rsk);
1803 /* If socket is aborted during connect operation */
1804 tcp_free_fastopen_req(tp);
1805 tcp_saved_syn_free(tp);
1807 sk_sockets_allocated_dec(sk);
1808 sock_release_memcg(sk);
1810 EXPORT_SYMBOL(tcp_v4_destroy_sock);
1812 #ifdef CONFIG_PROC_FS
1813 /* Proc filesystem TCP sock list dumping. */
1816 * Get next listener socket follow cur. If cur is NULL, get first socket
1817 * starting from bucket given in st->bucket; when st->bucket is zero the
1818 * very first socket in the hash table is returned.
1820 static void *listening_get_next(struct seq_file *seq, void *cur)
1822 struct inet_connection_sock *icsk;
1823 struct hlist_nulls_node *node;
1824 struct sock *sk = cur;
1825 struct inet_listen_hashbucket *ilb;
1826 struct tcp_iter_state *st = seq->private;
1827 struct net *net = seq_file_net(seq);
1830 ilb = &tcp_hashinfo.listening_hash[st->bucket];
1831 spin_lock_bh(&ilb->lock);
1832 sk = sk_nulls_head(&ilb->head);
1836 ilb = &tcp_hashinfo.listening_hash[st->bucket];
1840 sk = sk_nulls_next(sk);
1842 sk_nulls_for_each_from(sk, node) {
1843 if (!net_eq(sock_net(sk), net))
1845 if (sk->sk_family == st->family) {
1849 icsk = inet_csk(sk);
1851 spin_unlock_bh(&ilb->lock);
1853 if (++st->bucket < INET_LHTABLE_SIZE) {
1854 ilb = &tcp_hashinfo.listening_hash[st->bucket];
1855 spin_lock_bh(&ilb->lock);
1856 sk = sk_nulls_head(&ilb->head);
1864 static void *listening_get_idx(struct seq_file *seq, loff_t *pos)
1866 struct tcp_iter_state *st = seq->private;
1871 rc = listening_get_next(seq, NULL);
1873 while (rc && *pos) {
1874 rc = listening_get_next(seq, rc);
1880 static inline bool empty_bucket(const struct tcp_iter_state *st)
1882 return hlist_nulls_empty(&tcp_hashinfo.ehash[st->bucket].chain);
1886 * Get first established socket starting from bucket given in st->bucket.
1887 * If st->bucket is zero, the very first socket in the hash is returned.
1889 static void *established_get_first(struct seq_file *seq)
1891 struct tcp_iter_state *st = seq->private;
1892 struct net *net = seq_file_net(seq);
1896 for (; st->bucket <= tcp_hashinfo.ehash_mask; ++st->bucket) {
1898 struct hlist_nulls_node *node;
1899 spinlock_t *lock = inet_ehash_lockp(&tcp_hashinfo, st->bucket);
1901 /* Lockless fast path for the common case of empty buckets */
1902 if (empty_bucket(st))
1906 sk_nulls_for_each(sk, node, &tcp_hashinfo.ehash[st->bucket].chain) {
1907 if (sk->sk_family != st->family ||
1908 !net_eq(sock_net(sk), net)) {
1914 spin_unlock_bh(lock);
1920 static void *established_get_next(struct seq_file *seq, void *cur)
1922 struct sock *sk = cur;
1923 struct hlist_nulls_node *node;
1924 struct tcp_iter_state *st = seq->private;
1925 struct net *net = seq_file_net(seq);
1930 sk = sk_nulls_next(sk);
1932 sk_nulls_for_each_from(sk, node) {
1933 if (sk->sk_family == st->family && net_eq(sock_net(sk), net))
1937 spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
1939 return established_get_first(seq);
1942 static void *established_get_idx(struct seq_file *seq, loff_t pos)
1944 struct tcp_iter_state *st = seq->private;
1948 rc = established_get_first(seq);
1951 rc = established_get_next(seq, rc);
1957 static void *tcp_get_idx(struct seq_file *seq, loff_t pos)
1960 struct tcp_iter_state *st = seq->private;
1962 st->state = TCP_SEQ_STATE_LISTENING;
1963 rc = listening_get_idx(seq, &pos);
1966 st->state = TCP_SEQ_STATE_ESTABLISHED;
1967 rc = established_get_idx(seq, pos);
1973 static void *tcp_seek_last_pos(struct seq_file *seq)
1975 struct tcp_iter_state *st = seq->private;
1976 int offset = st->offset;
1977 int orig_num = st->num;
1980 switch (st->state) {
1981 case TCP_SEQ_STATE_LISTENING:
1982 if (st->bucket >= INET_LHTABLE_SIZE)
1984 st->state = TCP_SEQ_STATE_LISTENING;
1985 rc = listening_get_next(seq, NULL);
1986 while (offset-- && rc)
1987 rc = listening_get_next(seq, rc);
1991 st->state = TCP_SEQ_STATE_ESTABLISHED;
1993 case TCP_SEQ_STATE_ESTABLISHED:
1994 if (st->bucket > tcp_hashinfo.ehash_mask)
1996 rc = established_get_first(seq);
1997 while (offset-- && rc)
1998 rc = established_get_next(seq, rc);
2006 static void *tcp_seq_start(struct seq_file *seq, loff_t *pos)
2008 struct tcp_iter_state *st = seq->private;
2011 if (*pos && *pos == st->last_pos) {
2012 rc = tcp_seek_last_pos(seq);
2017 st->state = TCP_SEQ_STATE_LISTENING;
2021 rc = *pos ? tcp_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
2024 st->last_pos = *pos;
2028 static void *tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2030 struct tcp_iter_state *st = seq->private;
2033 if (v == SEQ_START_TOKEN) {
2034 rc = tcp_get_idx(seq, 0);
2038 switch (st->state) {
2039 case TCP_SEQ_STATE_LISTENING:
2040 rc = listening_get_next(seq, v);
2042 st->state = TCP_SEQ_STATE_ESTABLISHED;
2045 rc = established_get_first(seq);
2048 case TCP_SEQ_STATE_ESTABLISHED:
2049 rc = established_get_next(seq, v);
2054 st->last_pos = *pos;
2058 static void tcp_seq_stop(struct seq_file *seq, void *v)
2060 struct tcp_iter_state *st = seq->private;
2062 switch (st->state) {
2063 case TCP_SEQ_STATE_LISTENING:
2064 if (v != SEQ_START_TOKEN)
2065 spin_unlock_bh(&tcp_hashinfo.listening_hash[st->bucket].lock);
2067 case TCP_SEQ_STATE_ESTABLISHED:
2069 spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
2074 int tcp_seq_open(struct inode *inode, struct file *file)
2076 struct tcp_seq_afinfo *afinfo = PDE_DATA(inode);
2077 struct tcp_iter_state *s;
2080 err = seq_open_net(inode, file, &afinfo->seq_ops,
2081 sizeof(struct tcp_iter_state));
2085 s = ((struct seq_file *)file->private_data)->private;
2086 s->family = afinfo->family;
2090 EXPORT_SYMBOL(tcp_seq_open);
2092 int tcp_proc_register(struct net *net, struct tcp_seq_afinfo *afinfo)
2095 struct proc_dir_entry *p;
2097 afinfo->seq_ops.start = tcp_seq_start;
2098 afinfo->seq_ops.next = tcp_seq_next;
2099 afinfo->seq_ops.stop = tcp_seq_stop;
2101 p = proc_create_data(afinfo->name, S_IRUGO, net->proc_net,
2102 afinfo->seq_fops, afinfo);
2107 EXPORT_SYMBOL(tcp_proc_register);
2109 void tcp_proc_unregister(struct net *net, struct tcp_seq_afinfo *afinfo)
2111 remove_proc_entry(afinfo->name, net->proc_net);
2113 EXPORT_SYMBOL(tcp_proc_unregister);
2115 static void get_openreq4(const struct request_sock *req,
2116 struct seq_file *f, int i)
2118 const struct inet_request_sock *ireq = inet_rsk(req);
2119 long delta = req->rsk_timer.expires - jiffies;
2121 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2122 " %02X %08X:%08X %02X:%08lX %08X %5u %8d %u %d %pK",
2127 ntohs(ireq->ir_rmt_port),
2129 0, 0, /* could print option size, but that is af dependent. */
2130 1, /* timers active (only the expire timer) */
2131 jiffies_delta_to_clock_t(delta),
2133 from_kuid_munged(seq_user_ns(f),
2134 sock_i_uid(req->rsk_listener)),
2135 0, /* non standard timer */
2136 0, /* open_requests have no inode */
2141 static void get_tcp4_sock(struct sock *sk, struct seq_file *f, int i)
2144 unsigned long timer_expires;
2145 const struct tcp_sock *tp = tcp_sk(sk);
2146 const struct inet_connection_sock *icsk = inet_csk(sk);
2147 const struct inet_sock *inet = inet_sk(sk);
2148 const struct fastopen_queue *fastopenq = &icsk->icsk_accept_queue.fastopenq;
2149 __be32 dest = inet->inet_daddr;
2150 __be32 src = inet->inet_rcv_saddr;
2151 __u16 destp = ntohs(inet->inet_dport);
2152 __u16 srcp = ntohs(inet->inet_sport);
2155 if (icsk->icsk_pending == ICSK_TIME_RETRANS ||
2156 icsk->icsk_pending == ICSK_TIME_EARLY_RETRANS ||
2157 icsk->icsk_pending == ICSK_TIME_LOSS_PROBE) {
2159 timer_expires = icsk->icsk_timeout;
2160 } else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
2162 timer_expires = icsk->icsk_timeout;
2163 } else if (timer_pending(&sk->sk_timer)) {
2165 timer_expires = sk->sk_timer.expires;
2168 timer_expires = jiffies;
2171 if (sk->sk_state == TCP_LISTEN)
2172 rx_queue = sk->sk_ack_backlog;
2175 * because we dont lock socket, we might find a transient negative value
2177 rx_queue = max_t(int, tp->rcv_nxt - tp->copied_seq, 0);
2179 seq_printf(f, "%4d: %08X:%04X %08X:%04X %02X %08X:%08X %02X:%08lX "
2180 "%08X %5u %8d %lu %d %pK %lu %lu %u %u %d",
2181 i, src, srcp, dest, destp, sk->sk_state,
2182 tp->write_seq - tp->snd_una,
2185 jiffies_delta_to_clock_t(timer_expires - jiffies),
2186 icsk->icsk_retransmits,
2187 from_kuid_munged(seq_user_ns(f), sock_i_uid(sk)),
2188 icsk->icsk_probes_out,
2190 atomic_read(&sk->sk_refcnt), sk,
2191 jiffies_to_clock_t(icsk->icsk_rto),
2192 jiffies_to_clock_t(icsk->icsk_ack.ato),
2193 (icsk->icsk_ack.quick << 1) | icsk->icsk_ack.pingpong,
2195 sk->sk_state == TCP_LISTEN ?
2196 (fastopenq ? fastopenq->max_qlen : 0) :
2197 (tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh));
2200 static void get_timewait4_sock(const struct inet_timewait_sock *tw,
2201 struct seq_file *f, int i)
2203 long delta = tw->tw_timer.expires - jiffies;
2207 dest = tw->tw_daddr;
2208 src = tw->tw_rcv_saddr;
2209 destp = ntohs(tw->tw_dport);
2210 srcp = ntohs(tw->tw_sport);
2212 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2213 " %02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK",
2214 i, src, srcp, dest, destp, tw->tw_substate, 0, 0,
2215 3, jiffies_delta_to_clock_t(delta), 0, 0, 0, 0,
2216 atomic_read(&tw->tw_refcnt), tw);
2221 static int tcp4_seq_show(struct seq_file *seq, void *v)
2223 struct tcp_iter_state *st;
2224 struct sock *sk = v;
2226 seq_setwidth(seq, TMPSZ - 1);
2227 if (v == SEQ_START_TOKEN) {
2228 seq_puts(seq, " sl local_address rem_address st tx_queue "
2229 "rx_queue tr tm->when retrnsmt uid timeout "
2235 if (sk->sk_state == TCP_TIME_WAIT)
2236 get_timewait4_sock(v, seq, st->num);
2237 else if (sk->sk_state == TCP_NEW_SYN_RECV)
2238 get_openreq4(v, seq, st->num);
2240 get_tcp4_sock(v, seq, st->num);
2246 static const struct file_operations tcp_afinfo_seq_fops = {
2247 .owner = THIS_MODULE,
2248 .open = tcp_seq_open,
2250 .llseek = seq_lseek,
2251 .release = seq_release_net
2254 static struct tcp_seq_afinfo tcp4_seq_afinfo = {
2257 .seq_fops = &tcp_afinfo_seq_fops,
2259 .show = tcp4_seq_show,
2263 static int __net_init tcp4_proc_init_net(struct net *net)
2265 return tcp_proc_register(net, &tcp4_seq_afinfo);
2268 static void __net_exit tcp4_proc_exit_net(struct net *net)
2270 tcp_proc_unregister(net, &tcp4_seq_afinfo);
2273 static struct pernet_operations tcp4_net_ops = {
2274 .init = tcp4_proc_init_net,
2275 .exit = tcp4_proc_exit_net,
2278 int __init tcp4_proc_init(void)
2280 return register_pernet_subsys(&tcp4_net_ops);
2283 void tcp4_proc_exit(void)
2285 unregister_pernet_subsys(&tcp4_net_ops);
2287 #endif /* CONFIG_PROC_FS */
2289 struct proto tcp_prot = {
2291 .owner = THIS_MODULE,
2293 .connect = tcp_v4_connect,
2294 .disconnect = tcp_disconnect,
2295 .accept = inet_csk_accept,
2297 .init = tcp_v4_init_sock,
2298 .destroy = tcp_v4_destroy_sock,
2299 .shutdown = tcp_shutdown,
2300 .setsockopt = tcp_setsockopt,
2301 .getsockopt = tcp_getsockopt,
2302 .recvmsg = tcp_recvmsg,
2303 .sendmsg = tcp_sendmsg,
2304 .sendpage = tcp_sendpage,
2305 .backlog_rcv = tcp_v4_do_rcv,
2306 .release_cb = tcp_release_cb,
2308 .unhash = inet_unhash,
2309 .get_port = inet_csk_get_port,
2310 .enter_memory_pressure = tcp_enter_memory_pressure,
2311 .stream_memory_free = tcp_stream_memory_free,
2312 .sockets_allocated = &tcp_sockets_allocated,
2313 .orphan_count = &tcp_orphan_count,
2314 .memory_allocated = &tcp_memory_allocated,
2315 .memory_pressure = &tcp_memory_pressure,
2316 .sysctl_mem = sysctl_tcp_mem,
2317 .sysctl_wmem = sysctl_tcp_wmem,
2318 .sysctl_rmem = sysctl_tcp_rmem,
2319 .max_header = MAX_TCP_HEADER,
2320 .obj_size = sizeof(struct tcp_sock),
2321 .slab_flags = SLAB_DESTROY_BY_RCU,
2322 .twsk_prot = &tcp_timewait_sock_ops,
2323 .rsk_prot = &tcp_request_sock_ops,
2324 .h.hashinfo = &tcp_hashinfo,
2325 .no_autobind = true,
2326 #ifdef CONFIG_COMPAT
2327 .compat_setsockopt = compat_tcp_setsockopt,
2328 .compat_getsockopt = compat_tcp_getsockopt,
2330 #ifdef CONFIG_MEMCG_KMEM
2331 .init_cgroup = tcp_init_cgroup,
2332 .destroy_cgroup = tcp_destroy_cgroup,
2333 .proto_cgroup = tcp_proto_cgroup,
2336 EXPORT_SYMBOL(tcp_prot);
2338 static void __net_exit tcp_sk_exit(struct net *net)
2342 for_each_possible_cpu(cpu)
2343 inet_ctl_sock_destroy(*per_cpu_ptr(net->ipv4.tcp_sk, cpu));
2344 free_percpu(net->ipv4.tcp_sk);
2347 static int __net_init tcp_sk_init(struct net *net)
2351 net->ipv4.tcp_sk = alloc_percpu(struct sock *);
2352 if (!net->ipv4.tcp_sk)
2355 for_each_possible_cpu(cpu) {
2358 res = inet_ctl_sock_create(&sk, PF_INET, SOCK_RAW,
2362 *per_cpu_ptr(net->ipv4.tcp_sk, cpu) = sk;
2365 net->ipv4.sysctl_tcp_ecn = 2;
2366 net->ipv4.sysctl_tcp_ecn_fallback = 1;
2368 net->ipv4.sysctl_tcp_base_mss = TCP_BASE_MSS;
2369 net->ipv4.sysctl_tcp_probe_threshold = TCP_PROBE_THRESHOLD;
2370 net->ipv4.sysctl_tcp_probe_interval = TCP_PROBE_INTERVAL;
2379 static void __net_exit tcp_sk_exit_batch(struct list_head *net_exit_list)
2381 inet_twsk_purge(&tcp_hashinfo, &tcp_death_row, AF_INET);
2384 static struct pernet_operations __net_initdata tcp_sk_ops = {
2385 .init = tcp_sk_init,
2386 .exit = tcp_sk_exit,
2387 .exit_batch = tcp_sk_exit_batch,
2390 void __init tcp_v4_init(void)
2392 inet_hashinfo_init(&tcp_hashinfo);
2393 if (register_pernet_subsys(&tcp_sk_ops))
2394 panic("Failed to create the TCP control socket.\n");