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) ||
925 lockdep_is_held(&sk->sk_lock.slock));
927 md5sig = kmalloc(sizeof(*md5sig), gfp);
931 sk_nocaps_add(sk, NETIF_F_GSO_MASK);
932 INIT_HLIST_HEAD(&md5sig->head);
933 rcu_assign_pointer(tp->md5sig_info, md5sig);
936 key = sock_kmalloc(sk, sizeof(*key), gfp);
939 if (!tcp_alloc_md5sig_pool()) {
940 sock_kfree_s(sk, key, sizeof(*key));
944 memcpy(key->key, newkey, newkeylen);
945 key->keylen = newkeylen;
946 key->family = family;
947 memcpy(&key->addr, addr,
948 (family == AF_INET6) ? sizeof(struct in6_addr) :
949 sizeof(struct in_addr));
950 hlist_add_head_rcu(&key->node, &md5sig->head);
953 EXPORT_SYMBOL(tcp_md5_do_add);
955 int tcp_md5_do_del(struct sock *sk, const union tcp_md5_addr *addr, int family)
957 struct tcp_md5sig_key *key;
959 key = tcp_md5_do_lookup(sk, addr, family);
962 hlist_del_rcu(&key->node);
963 atomic_sub(sizeof(*key), &sk->sk_omem_alloc);
967 EXPORT_SYMBOL(tcp_md5_do_del);
969 static void tcp_clear_md5_list(struct sock *sk)
971 struct tcp_sock *tp = tcp_sk(sk);
972 struct tcp_md5sig_key *key;
973 struct hlist_node *n;
974 struct tcp_md5sig_info *md5sig;
976 md5sig = rcu_dereference_protected(tp->md5sig_info, 1);
978 hlist_for_each_entry_safe(key, n, &md5sig->head, node) {
979 hlist_del_rcu(&key->node);
980 atomic_sub(sizeof(*key), &sk->sk_omem_alloc);
985 static int tcp_v4_parse_md5_keys(struct sock *sk, char __user *optval,
988 struct tcp_md5sig cmd;
989 struct sockaddr_in *sin = (struct sockaddr_in *)&cmd.tcpm_addr;
991 if (optlen < sizeof(cmd))
994 if (copy_from_user(&cmd, optval, sizeof(cmd)))
997 if (sin->sin_family != AF_INET)
1000 if (!cmd.tcpm_keylen)
1001 return tcp_md5_do_del(sk, (union tcp_md5_addr *)&sin->sin_addr.s_addr,
1004 if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN)
1007 return tcp_md5_do_add(sk, (union tcp_md5_addr *)&sin->sin_addr.s_addr,
1008 AF_INET, cmd.tcpm_key, cmd.tcpm_keylen,
1012 static int tcp_v4_md5_hash_pseudoheader(struct tcp_md5sig_pool *hp,
1013 __be32 daddr, __be32 saddr, int nbytes)
1015 struct tcp4_pseudohdr *bp;
1016 struct scatterlist sg;
1018 bp = &hp->md5_blk.ip4;
1021 * 1. the TCP pseudo-header (in the order: source IP address,
1022 * destination IP address, zero-padded protocol number, and
1028 bp->protocol = IPPROTO_TCP;
1029 bp->len = cpu_to_be16(nbytes);
1031 sg_init_one(&sg, bp, sizeof(*bp));
1032 return crypto_hash_update(&hp->md5_desc, &sg, sizeof(*bp));
1035 static int tcp_v4_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key,
1036 __be32 daddr, __be32 saddr, const struct tcphdr *th)
1038 struct tcp_md5sig_pool *hp;
1039 struct hash_desc *desc;
1041 hp = tcp_get_md5sig_pool();
1043 goto clear_hash_noput;
1044 desc = &hp->md5_desc;
1046 if (crypto_hash_init(desc))
1048 if (tcp_v4_md5_hash_pseudoheader(hp, daddr, saddr, th->doff << 2))
1050 if (tcp_md5_hash_header(hp, th))
1052 if (tcp_md5_hash_key(hp, key))
1054 if (crypto_hash_final(desc, md5_hash))
1057 tcp_put_md5sig_pool();
1061 tcp_put_md5sig_pool();
1063 memset(md5_hash, 0, 16);
1067 int tcp_v4_md5_hash_skb(char *md5_hash, const struct tcp_md5sig_key *key,
1068 const struct sock *sk,
1069 const struct sk_buff *skb)
1071 struct tcp_md5sig_pool *hp;
1072 struct hash_desc *desc;
1073 const struct tcphdr *th = tcp_hdr(skb);
1074 __be32 saddr, daddr;
1076 if (sk) { /* valid for establish/request sockets */
1077 saddr = sk->sk_rcv_saddr;
1078 daddr = sk->sk_daddr;
1080 const struct iphdr *iph = ip_hdr(skb);
1085 hp = tcp_get_md5sig_pool();
1087 goto clear_hash_noput;
1088 desc = &hp->md5_desc;
1090 if (crypto_hash_init(desc))
1093 if (tcp_v4_md5_hash_pseudoheader(hp, daddr, saddr, skb->len))
1095 if (tcp_md5_hash_header(hp, th))
1097 if (tcp_md5_hash_skb_data(hp, skb, th->doff << 2))
1099 if (tcp_md5_hash_key(hp, key))
1101 if (crypto_hash_final(desc, md5_hash))
1104 tcp_put_md5sig_pool();
1108 tcp_put_md5sig_pool();
1110 memset(md5_hash, 0, 16);
1113 EXPORT_SYMBOL(tcp_v4_md5_hash_skb);
1117 /* Called with rcu_read_lock() */
1118 static bool tcp_v4_inbound_md5_hash(const struct sock *sk,
1119 const struct sk_buff *skb)
1121 #ifdef CONFIG_TCP_MD5SIG
1123 * This gets called for each TCP segment that arrives
1124 * so we want to be efficient.
1125 * We have 3 drop cases:
1126 * o No MD5 hash and one expected.
1127 * o MD5 hash and we're not expecting one.
1128 * o MD5 hash and its wrong.
1130 const __u8 *hash_location = NULL;
1131 struct tcp_md5sig_key *hash_expected;
1132 const struct iphdr *iph = ip_hdr(skb);
1133 const struct tcphdr *th = tcp_hdr(skb);
1135 unsigned char newhash[16];
1137 hash_expected = tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&iph->saddr,
1139 hash_location = tcp_parse_md5sig_option(th);
1141 /* We've parsed the options - do we have a hash? */
1142 if (!hash_expected && !hash_location)
1145 if (hash_expected && !hash_location) {
1146 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5NOTFOUND);
1150 if (!hash_expected && hash_location) {
1151 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5UNEXPECTED);
1155 /* Okay, so this is hash_expected and hash_location -
1156 * so we need to calculate the checksum.
1158 genhash = tcp_v4_md5_hash_skb(newhash,
1162 if (genhash || memcmp(hash_location, newhash, 16) != 0) {
1163 net_info_ratelimited("MD5 Hash failed for (%pI4, %d)->(%pI4, %d)%s\n",
1164 &iph->saddr, ntohs(th->source),
1165 &iph->daddr, ntohs(th->dest),
1166 genhash ? " tcp_v4_calc_md5_hash failed"
1175 static void tcp_v4_init_req(struct request_sock *req,
1176 const struct sock *sk_listener,
1177 struct sk_buff *skb)
1179 struct inet_request_sock *ireq = inet_rsk(req);
1181 sk_rcv_saddr_set(req_to_sk(req), ip_hdr(skb)->daddr);
1182 sk_daddr_set(req_to_sk(req), ip_hdr(skb)->saddr);
1183 ireq->no_srccheck = inet_sk(sk_listener)->transparent;
1184 ireq->opt = tcp_v4_save_options(skb);
1187 static struct dst_entry *tcp_v4_route_req(const struct sock *sk,
1189 const struct request_sock *req,
1192 struct dst_entry *dst = inet_csk_route_req(sk, &fl->u.ip4, req);
1195 if (fl->u.ip4.daddr == inet_rsk(req)->ir_rmt_addr)
1204 struct request_sock_ops tcp_request_sock_ops __read_mostly = {
1206 .obj_size = sizeof(struct tcp_request_sock),
1207 .rtx_syn_ack = tcp_rtx_synack,
1208 .send_ack = tcp_v4_reqsk_send_ack,
1209 .destructor = tcp_v4_reqsk_destructor,
1210 .send_reset = tcp_v4_send_reset,
1211 .syn_ack_timeout = tcp_syn_ack_timeout,
1214 static const struct tcp_request_sock_ops tcp_request_sock_ipv4_ops = {
1215 .mss_clamp = TCP_MSS_DEFAULT,
1216 #ifdef CONFIG_TCP_MD5SIG
1217 .req_md5_lookup = tcp_v4_md5_lookup,
1218 .calc_md5_hash = tcp_v4_md5_hash_skb,
1220 .init_req = tcp_v4_init_req,
1221 #ifdef CONFIG_SYN_COOKIES
1222 .cookie_init_seq = cookie_v4_init_sequence,
1224 .route_req = tcp_v4_route_req,
1225 .init_seq = tcp_v4_init_sequence,
1226 .send_synack = tcp_v4_send_synack,
1229 int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
1231 /* Never answer to SYNs send to broadcast or multicast */
1232 if (skb_rtable(skb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
1235 return tcp_conn_request(&tcp_request_sock_ops,
1236 &tcp_request_sock_ipv4_ops, sk, skb);
1239 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
1242 EXPORT_SYMBOL(tcp_v4_conn_request);
1246 * The three way handshake has completed - we got a valid synack -
1247 * now create the new socket.
1249 struct sock *tcp_v4_syn_recv_sock(const struct sock *sk, struct sk_buff *skb,
1250 struct request_sock *req,
1251 struct dst_entry *dst,
1252 struct request_sock *req_unhash,
1255 struct inet_request_sock *ireq;
1256 struct inet_sock *newinet;
1257 struct tcp_sock *newtp;
1259 #ifdef CONFIG_TCP_MD5SIG
1260 struct tcp_md5sig_key *key;
1262 struct ip_options_rcu *inet_opt;
1264 if (sk_acceptq_is_full(sk))
1267 newsk = tcp_create_openreq_child(sk, req, skb);
1271 newsk->sk_gso_type = SKB_GSO_TCPV4;
1272 inet_sk_rx_dst_set(newsk, skb);
1274 newtp = tcp_sk(newsk);
1275 newinet = inet_sk(newsk);
1276 ireq = inet_rsk(req);
1277 sk_daddr_set(newsk, ireq->ir_rmt_addr);
1278 sk_rcv_saddr_set(newsk, ireq->ir_loc_addr);
1279 newinet->inet_saddr = ireq->ir_loc_addr;
1280 inet_opt = ireq->opt;
1281 rcu_assign_pointer(newinet->inet_opt, inet_opt);
1283 newinet->mc_index = inet_iif(skb);
1284 newinet->mc_ttl = ip_hdr(skb)->ttl;
1285 newinet->rcv_tos = ip_hdr(skb)->tos;
1286 inet_csk(newsk)->icsk_ext_hdr_len = 0;
1288 inet_csk(newsk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
1289 newinet->inet_id = newtp->write_seq ^ jiffies;
1292 dst = inet_csk_route_child_sock(sk, newsk, req);
1296 /* syncookie case : see end of cookie_v4_check() */
1298 sk_setup_caps(newsk, dst);
1300 tcp_ca_openreq_child(newsk, dst);
1302 tcp_sync_mss(newsk, dst_mtu(dst));
1303 newtp->advmss = dst_metric_advmss(dst);
1304 if (tcp_sk(sk)->rx_opt.user_mss &&
1305 tcp_sk(sk)->rx_opt.user_mss < newtp->advmss)
1306 newtp->advmss = tcp_sk(sk)->rx_opt.user_mss;
1308 tcp_initialize_rcv_mss(newsk);
1310 #ifdef CONFIG_TCP_MD5SIG
1311 /* Copy over the MD5 key from the original socket */
1312 key = tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&newinet->inet_daddr,
1316 * We're using one, so create a matching key
1317 * on the newsk structure. If we fail to get
1318 * memory, then we end up not copying the key
1321 tcp_md5_do_add(newsk, (union tcp_md5_addr *)&newinet->inet_daddr,
1322 AF_INET, key->key, key->keylen, GFP_ATOMIC);
1323 sk_nocaps_add(newsk, NETIF_F_GSO_MASK);
1327 if (__inet_inherit_port(sk, newsk) < 0)
1329 *own_req = inet_ehash_nolisten(newsk, req_to_sk(req_unhash));
1331 tcp_move_syn(newtp, req);
1336 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
1340 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
1343 inet_csk_prepare_forced_close(newsk);
1347 EXPORT_SYMBOL(tcp_v4_syn_recv_sock);
1349 static struct sock *tcp_v4_cookie_check(struct sock *sk, struct sk_buff *skb)
1351 #ifdef CONFIG_SYN_COOKIES
1352 const struct tcphdr *th = tcp_hdr(skb);
1355 sk = cookie_v4_check(sk, skb);
1360 /* The socket must have it's spinlock held when we get
1361 * here, unless it is a TCP_LISTEN socket.
1363 * We have a potential double-lock case here, so even when
1364 * doing backlog processing we use the BH locking scheme.
1365 * This is because we cannot sleep with the original spinlock
1368 int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
1372 if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
1373 struct dst_entry *dst = sk->sk_rx_dst;
1375 sock_rps_save_rxhash(sk, skb);
1376 sk_mark_napi_id(sk, skb);
1378 if (inet_sk(sk)->rx_dst_ifindex != skb->skb_iif ||
1379 !dst->ops->check(dst, 0)) {
1381 sk->sk_rx_dst = NULL;
1384 tcp_rcv_established(sk, skb, tcp_hdr(skb), skb->len);
1388 if (tcp_checksum_complete(skb))
1391 if (sk->sk_state == TCP_LISTEN) {
1392 struct sock *nsk = tcp_v4_cookie_check(sk, skb);
1397 sock_rps_save_rxhash(nsk, skb);
1398 sk_mark_napi_id(nsk, skb);
1399 if (tcp_child_process(sk, nsk, skb)) {
1406 sock_rps_save_rxhash(sk, skb);
1408 if (tcp_rcv_state_process(sk, skb)) {
1415 tcp_v4_send_reset(rsk, skb);
1418 /* Be careful here. If this function gets more complicated and
1419 * gcc suffers from register pressure on the x86, sk (in %ebx)
1420 * might be destroyed here. This current version compiles correctly,
1421 * but you have been warned.
1426 TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_CSUMERRORS);
1427 TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_INERRS);
1430 EXPORT_SYMBOL(tcp_v4_do_rcv);
1432 void tcp_v4_early_demux(struct sk_buff *skb)
1434 const struct iphdr *iph;
1435 const struct tcphdr *th;
1438 if (skb->pkt_type != PACKET_HOST)
1441 if (!pskb_may_pull(skb, skb_transport_offset(skb) + sizeof(struct tcphdr)))
1447 if (th->doff < sizeof(struct tcphdr) / 4)
1450 sk = __inet_lookup_established(dev_net(skb->dev), &tcp_hashinfo,
1451 iph->saddr, th->source,
1452 iph->daddr, ntohs(th->dest),
1456 skb->destructor = sock_edemux;
1457 if (sk_fullsock(sk)) {
1458 struct dst_entry *dst = READ_ONCE(sk->sk_rx_dst);
1461 dst = dst_check(dst, 0);
1463 inet_sk(sk)->rx_dst_ifindex == skb->skb_iif)
1464 skb_dst_set_noref(skb, dst);
1469 /* Packet is added to VJ-style prequeue for processing in process
1470 * context, if a reader task is waiting. Apparently, this exciting
1471 * idea (VJ's mail "Re: query about TCP header on tcp-ip" of 07 Sep 93)
1472 * failed somewhere. Latency? Burstiness? Well, at least now we will
1473 * see, why it failed. 8)8) --ANK
1476 bool tcp_prequeue(struct sock *sk, struct sk_buff *skb)
1478 struct tcp_sock *tp = tcp_sk(sk);
1480 if (sysctl_tcp_low_latency || !tp->ucopy.task)
1483 if (skb->len <= tcp_hdrlen(skb) &&
1484 skb_queue_len(&tp->ucopy.prequeue) == 0)
1487 /* Before escaping RCU protected region, we need to take care of skb
1488 * dst. Prequeue is only enabled for established sockets.
1489 * For such sockets, we might need the skb dst only to set sk->sk_rx_dst
1490 * Instead of doing full sk_rx_dst validity here, let's perform
1491 * an optimistic check.
1493 if (likely(sk->sk_rx_dst))
1498 __skb_queue_tail(&tp->ucopy.prequeue, skb);
1499 tp->ucopy.memory += skb->truesize;
1500 if (tp->ucopy.memory > sk->sk_rcvbuf) {
1501 struct sk_buff *skb1;
1503 BUG_ON(sock_owned_by_user(sk));
1505 while ((skb1 = __skb_dequeue(&tp->ucopy.prequeue)) != NULL) {
1506 sk_backlog_rcv(sk, skb1);
1507 NET_INC_STATS_BH(sock_net(sk),
1508 LINUX_MIB_TCPPREQUEUEDROPPED);
1511 tp->ucopy.memory = 0;
1512 } else if (skb_queue_len(&tp->ucopy.prequeue) == 1) {
1513 wake_up_interruptible_sync_poll(sk_sleep(sk),
1514 POLLIN | POLLRDNORM | POLLRDBAND);
1515 if (!inet_csk_ack_scheduled(sk))
1516 inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK,
1517 (3 * tcp_rto_min(sk)) / 4,
1522 EXPORT_SYMBOL(tcp_prequeue);
1528 int tcp_v4_rcv(struct sk_buff *skb)
1530 const struct iphdr *iph;
1531 const struct tcphdr *th;
1534 struct net *net = dev_net(skb->dev);
1536 if (skb->pkt_type != PACKET_HOST)
1539 /* Count it even if it's bad */
1540 TCP_INC_STATS_BH(net, TCP_MIB_INSEGS);
1542 if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
1547 if (th->doff < sizeof(struct tcphdr) / 4)
1549 if (!pskb_may_pull(skb, th->doff * 4))
1552 /* An explanation is required here, I think.
1553 * Packet length and doff are validated by header prediction,
1554 * provided case of th->doff==0 is eliminated.
1555 * So, we defer the checks. */
1557 if (skb_checksum_init(skb, IPPROTO_TCP, inet_compute_pseudo))
1562 /* This is tricky : We move IPCB at its correct location into TCP_SKB_CB()
1563 * barrier() makes sure compiler wont play fool^Waliasing games.
1565 memmove(&TCP_SKB_CB(skb)->header.h4, IPCB(skb),
1566 sizeof(struct inet_skb_parm));
1569 TCP_SKB_CB(skb)->seq = ntohl(th->seq);
1570 TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
1571 skb->len - th->doff * 4);
1572 TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
1573 TCP_SKB_CB(skb)->tcp_flags = tcp_flag_byte(th);
1574 TCP_SKB_CB(skb)->tcp_tw_isn = 0;
1575 TCP_SKB_CB(skb)->ip_dsfield = ipv4_get_dsfield(iph);
1576 TCP_SKB_CB(skb)->sacked = 0;
1579 sk = __inet_lookup_skb(&tcp_hashinfo, skb, th->source, th->dest);
1584 if (sk->sk_state == TCP_TIME_WAIT)
1587 if (sk->sk_state == TCP_NEW_SYN_RECV) {
1588 struct request_sock *req = inet_reqsk(sk);
1589 struct sock *nsk = NULL;
1591 sk = req->rsk_listener;
1592 if (tcp_v4_inbound_md5_hash(sk, skb))
1593 goto discard_and_relse;
1594 if (likely(sk->sk_state == TCP_LISTEN)) {
1595 nsk = tcp_check_req(sk, skb, req, false);
1597 inet_csk_reqsk_queue_drop_and_put(sk, req);
1607 } else if (tcp_child_process(sk, nsk, skb)) {
1608 tcp_v4_send_reset(nsk, skb);
1614 if (unlikely(iph->ttl < inet_sk(sk)->min_ttl)) {
1615 NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP);
1616 goto discard_and_relse;
1619 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
1620 goto discard_and_relse;
1622 if (tcp_v4_inbound_md5_hash(sk, skb))
1623 goto discard_and_relse;
1627 if (sk_filter(sk, skb))
1628 goto discard_and_relse;
1632 if (sk->sk_state == TCP_LISTEN) {
1633 ret = tcp_v4_do_rcv(sk, skb);
1634 goto put_and_return;
1637 sk_incoming_cpu_update(sk);
1639 bh_lock_sock_nested(sk);
1640 tcp_sk(sk)->segs_in += max_t(u16, 1, skb_shinfo(skb)->gso_segs);
1642 if (!sock_owned_by_user(sk)) {
1643 if (!tcp_prequeue(sk, skb))
1644 ret = tcp_v4_do_rcv(sk, skb);
1645 } else if (unlikely(sk_add_backlog(sk, skb,
1646 sk->sk_rcvbuf + sk->sk_sndbuf))) {
1648 NET_INC_STATS_BH(net, LINUX_MIB_TCPBACKLOGDROP);
1649 goto discard_and_relse;
1659 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
1662 if (tcp_checksum_complete(skb)) {
1664 TCP_INC_STATS_BH(net, TCP_MIB_CSUMERRORS);
1666 TCP_INC_STATS_BH(net, TCP_MIB_INERRS);
1668 tcp_v4_send_reset(NULL, skb);
1672 /* Discard frame. */
1681 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
1682 inet_twsk_put(inet_twsk(sk));
1686 if (tcp_checksum_complete(skb)) {
1687 inet_twsk_put(inet_twsk(sk));
1690 switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) {
1692 struct sock *sk2 = inet_lookup_listener(dev_net(skb->dev),
1694 iph->saddr, th->source,
1695 iph->daddr, th->dest,
1698 inet_twsk_deschedule_put(inet_twsk(sk));
1702 /* Fall through to ACK */
1705 tcp_v4_timewait_ack(sk, skb);
1709 case TCP_TW_SUCCESS:;
1714 static struct timewait_sock_ops tcp_timewait_sock_ops = {
1715 .twsk_obj_size = sizeof(struct tcp_timewait_sock),
1716 .twsk_unique = tcp_twsk_unique,
1717 .twsk_destructor= tcp_twsk_destructor,
1720 void inet_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb)
1722 struct dst_entry *dst = skb_dst(skb);
1726 sk->sk_rx_dst = dst;
1727 inet_sk(sk)->rx_dst_ifindex = skb->skb_iif;
1730 EXPORT_SYMBOL(inet_sk_rx_dst_set);
1732 const struct inet_connection_sock_af_ops ipv4_specific = {
1733 .queue_xmit = ip_queue_xmit,
1734 .send_check = tcp_v4_send_check,
1735 .rebuild_header = inet_sk_rebuild_header,
1736 .sk_rx_dst_set = inet_sk_rx_dst_set,
1737 .conn_request = tcp_v4_conn_request,
1738 .syn_recv_sock = tcp_v4_syn_recv_sock,
1739 .net_header_len = sizeof(struct iphdr),
1740 .setsockopt = ip_setsockopt,
1741 .getsockopt = ip_getsockopt,
1742 .addr2sockaddr = inet_csk_addr2sockaddr,
1743 .sockaddr_len = sizeof(struct sockaddr_in),
1744 .bind_conflict = inet_csk_bind_conflict,
1745 #ifdef CONFIG_COMPAT
1746 .compat_setsockopt = compat_ip_setsockopt,
1747 .compat_getsockopt = compat_ip_getsockopt,
1749 .mtu_reduced = tcp_v4_mtu_reduced,
1751 EXPORT_SYMBOL(ipv4_specific);
1753 #ifdef CONFIG_TCP_MD5SIG
1754 static const struct tcp_sock_af_ops tcp_sock_ipv4_specific = {
1755 .md5_lookup = tcp_v4_md5_lookup,
1756 .calc_md5_hash = tcp_v4_md5_hash_skb,
1757 .md5_parse = tcp_v4_parse_md5_keys,
1761 /* NOTE: A lot of things set to zero explicitly by call to
1762 * sk_alloc() so need not be done here.
1764 static int tcp_v4_init_sock(struct sock *sk)
1766 struct inet_connection_sock *icsk = inet_csk(sk);
1770 icsk->icsk_af_ops = &ipv4_specific;
1772 #ifdef CONFIG_TCP_MD5SIG
1773 tcp_sk(sk)->af_specific = &tcp_sock_ipv4_specific;
1779 void tcp_v4_destroy_sock(struct sock *sk)
1781 struct tcp_sock *tp = tcp_sk(sk);
1783 tcp_clear_xmit_timers(sk);
1785 tcp_cleanup_congestion_control(sk);
1787 /* Cleanup up the write buffer. */
1788 tcp_write_queue_purge(sk);
1790 /* Cleans up our, hopefully empty, out_of_order_queue. */
1791 __skb_queue_purge(&tp->out_of_order_queue);
1793 #ifdef CONFIG_TCP_MD5SIG
1794 /* Clean up the MD5 key list, if any */
1795 if (tp->md5sig_info) {
1796 tcp_clear_md5_list(sk);
1797 kfree_rcu(tp->md5sig_info, rcu);
1798 tp->md5sig_info = NULL;
1802 /* Clean prequeue, it must be empty really */
1803 __skb_queue_purge(&tp->ucopy.prequeue);
1805 /* Clean up a referenced TCP bind bucket. */
1806 if (inet_csk(sk)->icsk_bind_hash)
1809 BUG_ON(tp->fastopen_rsk);
1811 /* If socket is aborted during connect operation */
1812 tcp_free_fastopen_req(tp);
1813 tcp_saved_syn_free(tp);
1815 sk_sockets_allocated_dec(sk);
1816 sock_release_memcg(sk);
1818 EXPORT_SYMBOL(tcp_v4_destroy_sock);
1820 #ifdef CONFIG_PROC_FS
1821 /* Proc filesystem TCP sock list dumping. */
1824 * Get next listener socket follow cur. If cur is NULL, get first socket
1825 * starting from bucket given in st->bucket; when st->bucket is zero the
1826 * very first socket in the hash table is returned.
1828 static void *listening_get_next(struct seq_file *seq, void *cur)
1830 struct inet_connection_sock *icsk;
1831 struct hlist_nulls_node *node;
1832 struct sock *sk = cur;
1833 struct inet_listen_hashbucket *ilb;
1834 struct tcp_iter_state *st = seq->private;
1835 struct net *net = seq_file_net(seq);
1838 ilb = &tcp_hashinfo.listening_hash[st->bucket];
1839 spin_lock_bh(&ilb->lock);
1840 sk = sk_nulls_head(&ilb->head);
1844 ilb = &tcp_hashinfo.listening_hash[st->bucket];
1848 sk = sk_nulls_next(sk);
1850 sk_nulls_for_each_from(sk, node) {
1851 if (!net_eq(sock_net(sk), net))
1853 if (sk->sk_family == st->family) {
1857 icsk = inet_csk(sk);
1859 spin_unlock_bh(&ilb->lock);
1861 if (++st->bucket < INET_LHTABLE_SIZE) {
1862 ilb = &tcp_hashinfo.listening_hash[st->bucket];
1863 spin_lock_bh(&ilb->lock);
1864 sk = sk_nulls_head(&ilb->head);
1872 static void *listening_get_idx(struct seq_file *seq, loff_t *pos)
1874 struct tcp_iter_state *st = seq->private;
1879 rc = listening_get_next(seq, NULL);
1881 while (rc && *pos) {
1882 rc = listening_get_next(seq, rc);
1888 static inline bool empty_bucket(const struct tcp_iter_state *st)
1890 return hlist_nulls_empty(&tcp_hashinfo.ehash[st->bucket].chain);
1894 * Get first established socket starting from bucket given in st->bucket.
1895 * If st->bucket is zero, the very first socket in the hash is returned.
1897 static void *established_get_first(struct seq_file *seq)
1899 struct tcp_iter_state *st = seq->private;
1900 struct net *net = seq_file_net(seq);
1904 for (; st->bucket <= tcp_hashinfo.ehash_mask; ++st->bucket) {
1906 struct hlist_nulls_node *node;
1907 spinlock_t *lock = inet_ehash_lockp(&tcp_hashinfo, st->bucket);
1909 /* Lockless fast path for the common case of empty buckets */
1910 if (empty_bucket(st))
1914 sk_nulls_for_each(sk, node, &tcp_hashinfo.ehash[st->bucket].chain) {
1915 if (sk->sk_family != st->family ||
1916 !net_eq(sock_net(sk), net)) {
1922 spin_unlock_bh(lock);
1928 static void *established_get_next(struct seq_file *seq, void *cur)
1930 struct sock *sk = cur;
1931 struct hlist_nulls_node *node;
1932 struct tcp_iter_state *st = seq->private;
1933 struct net *net = seq_file_net(seq);
1938 sk = sk_nulls_next(sk);
1940 sk_nulls_for_each_from(sk, node) {
1941 if (sk->sk_family == st->family && net_eq(sock_net(sk), net))
1945 spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
1947 return established_get_first(seq);
1950 static void *established_get_idx(struct seq_file *seq, loff_t pos)
1952 struct tcp_iter_state *st = seq->private;
1956 rc = established_get_first(seq);
1959 rc = established_get_next(seq, rc);
1965 static void *tcp_get_idx(struct seq_file *seq, loff_t pos)
1968 struct tcp_iter_state *st = seq->private;
1970 st->state = TCP_SEQ_STATE_LISTENING;
1971 rc = listening_get_idx(seq, &pos);
1974 st->state = TCP_SEQ_STATE_ESTABLISHED;
1975 rc = established_get_idx(seq, pos);
1981 static void *tcp_seek_last_pos(struct seq_file *seq)
1983 struct tcp_iter_state *st = seq->private;
1984 int offset = st->offset;
1985 int orig_num = st->num;
1988 switch (st->state) {
1989 case TCP_SEQ_STATE_LISTENING:
1990 if (st->bucket >= INET_LHTABLE_SIZE)
1992 st->state = TCP_SEQ_STATE_LISTENING;
1993 rc = listening_get_next(seq, NULL);
1994 while (offset-- && rc)
1995 rc = listening_get_next(seq, rc);
1999 st->state = TCP_SEQ_STATE_ESTABLISHED;
2001 case TCP_SEQ_STATE_ESTABLISHED:
2002 if (st->bucket > tcp_hashinfo.ehash_mask)
2004 rc = established_get_first(seq);
2005 while (offset-- && rc)
2006 rc = established_get_next(seq, rc);
2014 static void *tcp_seq_start(struct seq_file *seq, loff_t *pos)
2016 struct tcp_iter_state *st = seq->private;
2019 if (*pos && *pos == st->last_pos) {
2020 rc = tcp_seek_last_pos(seq);
2025 st->state = TCP_SEQ_STATE_LISTENING;
2029 rc = *pos ? tcp_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
2032 st->last_pos = *pos;
2036 static void *tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2038 struct tcp_iter_state *st = seq->private;
2041 if (v == SEQ_START_TOKEN) {
2042 rc = tcp_get_idx(seq, 0);
2046 switch (st->state) {
2047 case TCP_SEQ_STATE_LISTENING:
2048 rc = listening_get_next(seq, v);
2050 st->state = TCP_SEQ_STATE_ESTABLISHED;
2053 rc = established_get_first(seq);
2056 case TCP_SEQ_STATE_ESTABLISHED:
2057 rc = established_get_next(seq, v);
2062 st->last_pos = *pos;
2066 static void tcp_seq_stop(struct seq_file *seq, void *v)
2068 struct tcp_iter_state *st = seq->private;
2070 switch (st->state) {
2071 case TCP_SEQ_STATE_LISTENING:
2072 if (v != SEQ_START_TOKEN)
2073 spin_unlock_bh(&tcp_hashinfo.listening_hash[st->bucket].lock);
2075 case TCP_SEQ_STATE_ESTABLISHED:
2077 spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
2082 int tcp_seq_open(struct inode *inode, struct file *file)
2084 struct tcp_seq_afinfo *afinfo = PDE_DATA(inode);
2085 struct tcp_iter_state *s;
2088 err = seq_open_net(inode, file, &afinfo->seq_ops,
2089 sizeof(struct tcp_iter_state));
2093 s = ((struct seq_file *)file->private_data)->private;
2094 s->family = afinfo->family;
2098 EXPORT_SYMBOL(tcp_seq_open);
2100 int tcp_proc_register(struct net *net, struct tcp_seq_afinfo *afinfo)
2103 struct proc_dir_entry *p;
2105 afinfo->seq_ops.start = tcp_seq_start;
2106 afinfo->seq_ops.next = tcp_seq_next;
2107 afinfo->seq_ops.stop = tcp_seq_stop;
2109 p = proc_create_data(afinfo->name, S_IRUGO, net->proc_net,
2110 afinfo->seq_fops, afinfo);
2115 EXPORT_SYMBOL(tcp_proc_register);
2117 void tcp_proc_unregister(struct net *net, struct tcp_seq_afinfo *afinfo)
2119 remove_proc_entry(afinfo->name, net->proc_net);
2121 EXPORT_SYMBOL(tcp_proc_unregister);
2123 static void get_openreq4(const struct request_sock *req,
2124 struct seq_file *f, int i)
2126 const struct inet_request_sock *ireq = inet_rsk(req);
2127 long delta = req->rsk_timer.expires - jiffies;
2129 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2130 " %02X %08X:%08X %02X:%08lX %08X %5u %8d %u %d %pK",
2135 ntohs(ireq->ir_rmt_port),
2137 0, 0, /* could print option size, but that is af dependent. */
2138 1, /* timers active (only the expire timer) */
2139 jiffies_delta_to_clock_t(delta),
2141 from_kuid_munged(seq_user_ns(f),
2142 sock_i_uid(req->rsk_listener)),
2143 0, /* non standard timer */
2144 0, /* open_requests have no inode */
2149 static void get_tcp4_sock(struct sock *sk, struct seq_file *f, int i)
2152 unsigned long timer_expires;
2153 const struct tcp_sock *tp = tcp_sk(sk);
2154 const struct inet_connection_sock *icsk = inet_csk(sk);
2155 const struct inet_sock *inet = inet_sk(sk);
2156 const struct fastopen_queue *fastopenq = &icsk->icsk_accept_queue.fastopenq;
2157 __be32 dest = inet->inet_daddr;
2158 __be32 src = inet->inet_rcv_saddr;
2159 __u16 destp = ntohs(inet->inet_dport);
2160 __u16 srcp = ntohs(inet->inet_sport);
2164 if (icsk->icsk_pending == ICSK_TIME_RETRANS ||
2165 icsk->icsk_pending == ICSK_TIME_EARLY_RETRANS ||
2166 icsk->icsk_pending == ICSK_TIME_LOSS_PROBE) {
2168 timer_expires = icsk->icsk_timeout;
2169 } else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
2171 timer_expires = icsk->icsk_timeout;
2172 } else if (timer_pending(&sk->sk_timer)) {
2174 timer_expires = sk->sk_timer.expires;
2177 timer_expires = jiffies;
2180 state = sk_state_load(sk);
2181 if (state == TCP_LISTEN)
2182 rx_queue = sk->sk_ack_backlog;
2184 /* Because we don't lock the socket,
2185 * we might find a transient negative value.
2187 rx_queue = max_t(int, tp->rcv_nxt - tp->copied_seq, 0);
2189 seq_printf(f, "%4d: %08X:%04X %08X:%04X %02X %08X:%08X %02X:%08lX "
2190 "%08X %5u %8d %lu %d %pK %lu %lu %u %u %d",
2191 i, src, srcp, dest, destp, state,
2192 tp->write_seq - tp->snd_una,
2195 jiffies_delta_to_clock_t(timer_expires - jiffies),
2196 icsk->icsk_retransmits,
2197 from_kuid_munged(seq_user_ns(f), sock_i_uid(sk)),
2198 icsk->icsk_probes_out,
2200 atomic_read(&sk->sk_refcnt), sk,
2201 jiffies_to_clock_t(icsk->icsk_rto),
2202 jiffies_to_clock_t(icsk->icsk_ack.ato),
2203 (icsk->icsk_ack.quick << 1) | icsk->icsk_ack.pingpong,
2205 state == TCP_LISTEN ?
2206 fastopenq->max_qlen :
2207 (tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh));
2210 static void get_timewait4_sock(const struct inet_timewait_sock *tw,
2211 struct seq_file *f, int i)
2213 long delta = tw->tw_timer.expires - jiffies;
2217 dest = tw->tw_daddr;
2218 src = tw->tw_rcv_saddr;
2219 destp = ntohs(tw->tw_dport);
2220 srcp = ntohs(tw->tw_sport);
2222 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2223 " %02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK",
2224 i, src, srcp, dest, destp, tw->tw_substate, 0, 0,
2225 3, jiffies_delta_to_clock_t(delta), 0, 0, 0, 0,
2226 atomic_read(&tw->tw_refcnt), tw);
2231 static int tcp4_seq_show(struct seq_file *seq, void *v)
2233 struct tcp_iter_state *st;
2234 struct sock *sk = v;
2236 seq_setwidth(seq, TMPSZ - 1);
2237 if (v == SEQ_START_TOKEN) {
2238 seq_puts(seq, " sl local_address rem_address st tx_queue "
2239 "rx_queue tr tm->when retrnsmt uid timeout "
2245 if (sk->sk_state == TCP_TIME_WAIT)
2246 get_timewait4_sock(v, seq, st->num);
2247 else if (sk->sk_state == TCP_NEW_SYN_RECV)
2248 get_openreq4(v, seq, st->num);
2250 get_tcp4_sock(v, seq, st->num);
2256 static const struct file_operations tcp_afinfo_seq_fops = {
2257 .owner = THIS_MODULE,
2258 .open = tcp_seq_open,
2260 .llseek = seq_lseek,
2261 .release = seq_release_net
2264 static struct tcp_seq_afinfo tcp4_seq_afinfo = {
2267 .seq_fops = &tcp_afinfo_seq_fops,
2269 .show = tcp4_seq_show,
2273 static int __net_init tcp4_proc_init_net(struct net *net)
2275 return tcp_proc_register(net, &tcp4_seq_afinfo);
2278 static void __net_exit tcp4_proc_exit_net(struct net *net)
2280 tcp_proc_unregister(net, &tcp4_seq_afinfo);
2283 static struct pernet_operations tcp4_net_ops = {
2284 .init = tcp4_proc_init_net,
2285 .exit = tcp4_proc_exit_net,
2288 int __init tcp4_proc_init(void)
2290 return register_pernet_subsys(&tcp4_net_ops);
2293 void tcp4_proc_exit(void)
2295 unregister_pernet_subsys(&tcp4_net_ops);
2297 #endif /* CONFIG_PROC_FS */
2299 struct proto tcp_prot = {
2301 .owner = THIS_MODULE,
2303 .connect = tcp_v4_connect,
2304 .disconnect = tcp_disconnect,
2305 .accept = inet_csk_accept,
2307 .init = tcp_v4_init_sock,
2308 .destroy = tcp_v4_destroy_sock,
2309 .shutdown = tcp_shutdown,
2310 .setsockopt = tcp_setsockopt,
2311 .getsockopt = tcp_getsockopt,
2312 .recvmsg = tcp_recvmsg,
2313 .sendmsg = tcp_sendmsg,
2314 .sendpage = tcp_sendpage,
2315 .backlog_rcv = tcp_v4_do_rcv,
2316 .release_cb = tcp_release_cb,
2318 .unhash = inet_unhash,
2319 .get_port = inet_csk_get_port,
2320 .enter_memory_pressure = tcp_enter_memory_pressure,
2321 .stream_memory_free = tcp_stream_memory_free,
2322 .sockets_allocated = &tcp_sockets_allocated,
2323 .orphan_count = &tcp_orphan_count,
2324 .memory_allocated = &tcp_memory_allocated,
2325 .memory_pressure = &tcp_memory_pressure,
2326 .sysctl_mem = sysctl_tcp_mem,
2327 .sysctl_wmem = sysctl_tcp_wmem,
2328 .sysctl_rmem = sysctl_tcp_rmem,
2329 .max_header = MAX_TCP_HEADER,
2330 .obj_size = sizeof(struct tcp_sock),
2331 .slab_flags = SLAB_DESTROY_BY_RCU,
2332 .twsk_prot = &tcp_timewait_sock_ops,
2333 .rsk_prot = &tcp_request_sock_ops,
2334 .h.hashinfo = &tcp_hashinfo,
2335 .no_autobind = true,
2336 #ifdef CONFIG_COMPAT
2337 .compat_setsockopt = compat_tcp_setsockopt,
2338 .compat_getsockopt = compat_tcp_getsockopt,
2340 #ifdef CONFIG_MEMCG_KMEM
2341 .init_cgroup = tcp_init_cgroup,
2342 .destroy_cgroup = tcp_destroy_cgroup,
2343 .proto_cgroup = tcp_proto_cgroup,
2346 EXPORT_SYMBOL(tcp_prot);
2348 static void __net_exit tcp_sk_exit(struct net *net)
2352 for_each_possible_cpu(cpu)
2353 inet_ctl_sock_destroy(*per_cpu_ptr(net->ipv4.tcp_sk, cpu));
2354 free_percpu(net->ipv4.tcp_sk);
2357 static int __net_init tcp_sk_init(struct net *net)
2361 net->ipv4.tcp_sk = alloc_percpu(struct sock *);
2362 if (!net->ipv4.tcp_sk)
2365 for_each_possible_cpu(cpu) {
2368 res = inet_ctl_sock_create(&sk, PF_INET, SOCK_RAW,
2372 *per_cpu_ptr(net->ipv4.tcp_sk, cpu) = sk;
2375 net->ipv4.sysctl_tcp_ecn = 2;
2376 net->ipv4.sysctl_tcp_ecn_fallback = 1;
2378 net->ipv4.sysctl_tcp_base_mss = TCP_BASE_MSS;
2379 net->ipv4.sysctl_tcp_probe_threshold = TCP_PROBE_THRESHOLD;
2380 net->ipv4.sysctl_tcp_probe_interval = TCP_PROBE_INTERVAL;
2389 static void __net_exit tcp_sk_exit_batch(struct list_head *net_exit_list)
2391 inet_twsk_purge(&tcp_hashinfo, &tcp_death_row, AF_INET);
2394 static struct pernet_operations __net_initdata tcp_sk_ops = {
2395 .init = tcp_sk_init,
2396 .exit = tcp_sk_exit,
2397 .exit_batch = tcp_sk_exit_batch,
2400 void __init tcp_v4_init(void)
2402 inet_hashinfo_init(&tcp_hashinfo);
2403 if (register_pernet_subsys(&tcp_sk_ops))
2404 panic("Failed to create the TCP control socket.\n");