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, bool abort)
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.
323 if (seq != tcp_rsk(req)->snt_isn) {
324 NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
327 * Still in SYN_RECV, just remove it silently.
328 * There is no good way to pass the error to the newly
329 * created socket, and POSIX does not want network
330 * errors returned from accept().
332 inet_csk_reqsk_queue_drop(req->rsk_listener, req);
333 NET_INC_STATS_BH(net, LINUX_MIB_LISTENDROPS);
337 EXPORT_SYMBOL(tcp_req_err);
340 * This routine is called by the ICMP module when it gets some
341 * sort of error condition. If err < 0 then the socket should
342 * be closed and the error returned to the user. If err > 0
343 * it's just the icmp type << 8 | icmp code. After adjustment
344 * header points to the first 8 bytes of the tcp header. We need
345 * to find the appropriate port.
347 * The locking strategy used here is very "optimistic". When
348 * someone else accesses the socket the ICMP is just dropped
349 * and for some paths there is no check at all.
350 * A more general error queue to queue errors for later handling
351 * is probably better.
355 void tcp_v4_err(struct sk_buff *icmp_skb, u32 info)
357 const struct iphdr *iph = (const struct iphdr *)icmp_skb->data;
358 struct tcphdr *th = (struct tcphdr *)(icmp_skb->data + (iph->ihl << 2));
359 struct inet_connection_sock *icsk;
361 struct inet_sock *inet;
362 const int type = icmp_hdr(icmp_skb)->type;
363 const int code = icmp_hdr(icmp_skb)->code;
366 struct request_sock *fastopen;
370 struct net *net = dev_net(icmp_skb->dev);
372 sk = __inet_lookup_established(net, &tcp_hashinfo, iph->daddr,
373 th->dest, iph->saddr, ntohs(th->source),
376 ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS);
379 if (sk->sk_state == TCP_TIME_WAIT) {
380 inet_twsk_put(inet_twsk(sk));
383 seq = ntohl(th->seq);
384 if (sk->sk_state == TCP_NEW_SYN_RECV)
385 return tcp_req_err(sk, seq,
386 type == ICMP_PARAMETERPROB ||
387 type == ICMP_TIME_EXCEEDED ||
388 (type == ICMP_DEST_UNREACH &&
389 (code == ICMP_NET_UNREACH ||
390 code == ICMP_HOST_UNREACH)));
393 /* If too many ICMPs get dropped on busy
394 * servers this needs to be solved differently.
395 * We do take care of PMTU discovery (RFC1191) special case :
396 * we can receive locally generated ICMP messages while socket is held.
398 if (sock_owned_by_user(sk)) {
399 if (!(type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED))
400 NET_INC_STATS_BH(net, LINUX_MIB_LOCKDROPPEDICMPS);
402 if (sk->sk_state == TCP_CLOSE)
405 if (unlikely(iph->ttl < inet_sk(sk)->min_ttl)) {
406 NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP);
412 /* XXX (TFO) - tp->snd_una should be ISN (tcp_create_openreq_child() */
413 fastopen = tp->fastopen_rsk;
414 snd_una = fastopen ? tcp_rsk(fastopen)->snt_isn : tp->snd_una;
415 if (sk->sk_state != TCP_LISTEN &&
416 !between(seq, snd_una, tp->snd_nxt)) {
417 NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
423 do_redirect(icmp_skb, sk);
425 case ICMP_SOURCE_QUENCH:
426 /* Just silently ignore these. */
428 case ICMP_PARAMETERPROB:
431 case ICMP_DEST_UNREACH:
432 if (code > NR_ICMP_UNREACH)
435 if (code == ICMP_FRAG_NEEDED) { /* PMTU discovery (RFC1191) */
436 /* We are not interested in TCP_LISTEN and open_requests
437 * (SYN-ACKs send out by Linux are always <576bytes so
438 * they should go through unfragmented).
440 if (sk->sk_state == TCP_LISTEN)
444 if (!sock_owned_by_user(sk)) {
445 tcp_v4_mtu_reduced(sk);
447 if (!test_and_set_bit(TCP_MTU_REDUCED_DEFERRED, &tp->tsq_flags))
453 err = icmp_err_convert[code].errno;
454 /* check if icmp_skb allows revert of backoff
455 * (see draft-zimmermann-tcp-lcd) */
456 if (code != ICMP_NET_UNREACH && code != ICMP_HOST_UNREACH)
458 if (seq != tp->snd_una || !icsk->icsk_retransmits ||
459 !icsk->icsk_backoff || fastopen)
462 if (sock_owned_by_user(sk))
465 icsk->icsk_backoff--;
466 icsk->icsk_rto = tp->srtt_us ? __tcp_set_rto(tp) :
468 icsk->icsk_rto = inet_csk_rto_backoff(icsk, TCP_RTO_MAX);
470 skb = tcp_write_queue_head(sk);
473 remaining = icsk->icsk_rto -
475 tcp_time_stamp - tcp_skb_timestamp(skb));
478 inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
479 remaining, TCP_RTO_MAX);
481 /* RTO revert clocked out retransmission.
482 * Will retransmit now */
483 tcp_retransmit_timer(sk);
487 case ICMP_TIME_EXCEEDED:
494 switch (sk->sk_state) {
497 /* Only in fast or simultaneous open. If a fast open socket is
498 * is already accepted it is treated as a connected one below.
500 if (fastopen && !fastopen->sk)
503 if (!sock_owned_by_user(sk)) {
506 sk->sk_error_report(sk);
510 sk->sk_err_soft = err;
515 /* If we've already connected we will keep trying
516 * until we time out, or the user gives up.
518 * rfc1122 4.2.3.9 allows to consider as hard errors
519 * only PROTO_UNREACH and PORT_UNREACH (well, FRAG_FAILED too,
520 * but it is obsoleted by pmtu discovery).
522 * Note, that in modern internet, where routing is unreliable
523 * and in each dark corner broken firewalls sit, sending random
524 * errors ordered by their masters even this two messages finally lose
525 * their original sense (even Linux sends invalid PORT_UNREACHs)
527 * Now we are in compliance with RFCs.
532 if (!sock_owned_by_user(sk) && inet->recverr) {
534 sk->sk_error_report(sk);
535 } else { /* Only an error on timeout */
536 sk->sk_err_soft = err;
544 void __tcp_v4_send_check(struct sk_buff *skb, __be32 saddr, __be32 daddr)
546 struct tcphdr *th = tcp_hdr(skb);
548 if (skb->ip_summed == CHECKSUM_PARTIAL) {
549 th->check = ~tcp_v4_check(skb->len, saddr, daddr, 0);
550 skb->csum_start = skb_transport_header(skb) - skb->head;
551 skb->csum_offset = offsetof(struct tcphdr, check);
553 th->check = tcp_v4_check(skb->len, saddr, daddr,
560 /* This routine computes an IPv4 TCP checksum. */
561 void tcp_v4_send_check(struct sock *sk, struct sk_buff *skb)
563 const struct inet_sock *inet = inet_sk(sk);
565 __tcp_v4_send_check(skb, inet->inet_saddr, inet->inet_daddr);
567 EXPORT_SYMBOL(tcp_v4_send_check);
570 * This routine will send an RST to the other tcp.
572 * Someone asks: why I NEVER use socket parameters (TOS, TTL etc.)
574 * Answer: if a packet caused RST, it is not for a socket
575 * existing in our system, if it is matched to a socket,
576 * it is just duplicate segment or bug in other side's TCP.
577 * So that we build reply only basing on parameters
578 * arrived with segment.
579 * Exception: precedence violation. We do not implement it in any case.
582 static void tcp_v4_send_reset(const struct sock *sk, struct sk_buff *skb)
584 const struct tcphdr *th = tcp_hdr(skb);
587 #ifdef CONFIG_TCP_MD5SIG
588 __be32 opt[(TCPOLEN_MD5SIG_ALIGNED >> 2)];
591 struct ip_reply_arg arg;
592 #ifdef CONFIG_TCP_MD5SIG
593 struct tcp_md5sig_key *key;
594 const __u8 *hash_location = NULL;
595 unsigned char newhash[16];
597 struct sock *sk1 = NULL;
601 /* Never send a reset in response to a reset. */
605 /* If sk not NULL, it means we did a successful lookup and incoming
606 * route had to be correct. prequeue might have dropped our dst.
608 if (!sk && skb_rtable(skb)->rt_type != RTN_LOCAL)
611 /* Swap the send and the receive. */
612 memset(&rep, 0, sizeof(rep));
613 rep.th.dest = th->source;
614 rep.th.source = th->dest;
615 rep.th.doff = sizeof(struct tcphdr) / 4;
619 rep.th.seq = th->ack_seq;
622 rep.th.ack_seq = htonl(ntohl(th->seq) + th->syn + th->fin +
623 skb->len - (th->doff << 2));
626 memset(&arg, 0, sizeof(arg));
627 arg.iov[0].iov_base = (unsigned char *)&rep;
628 arg.iov[0].iov_len = sizeof(rep.th);
630 net = sk ? sock_net(sk) : dev_net(skb_dst(skb)->dev);
631 #ifdef CONFIG_TCP_MD5SIG
632 hash_location = tcp_parse_md5sig_option(th);
633 if (!sk && hash_location) {
635 * active side is lost. Try to find listening socket through
636 * source port, and then find md5 key through listening socket.
637 * we are not loose security here:
638 * Incoming packet is checked with md5 hash with finding key,
639 * no RST generated if md5 hash doesn't match.
641 sk1 = __inet_lookup_listener(net,
642 &tcp_hashinfo, ip_hdr(skb)->saddr,
643 th->source, ip_hdr(skb)->daddr,
644 ntohs(th->source), inet_iif(skb));
645 /* don't send rst if it can't find key */
649 key = tcp_md5_do_lookup(sk1, (union tcp_md5_addr *)
650 &ip_hdr(skb)->saddr, AF_INET);
654 genhash = tcp_v4_md5_hash_skb(newhash, key, NULL, skb);
655 if (genhash || memcmp(hash_location, newhash, 16) != 0)
658 key = sk ? tcp_md5_do_lookup(sk, (union tcp_md5_addr *)
664 rep.opt[0] = htonl((TCPOPT_NOP << 24) |
666 (TCPOPT_MD5SIG << 8) |
668 /* Update length and the length the header thinks exists */
669 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED;
670 rep.th.doff = arg.iov[0].iov_len / 4;
672 tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[1],
673 key, ip_hdr(skb)->saddr,
674 ip_hdr(skb)->daddr, &rep.th);
677 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
678 ip_hdr(skb)->saddr, /* XXX */
679 arg.iov[0].iov_len, IPPROTO_TCP, 0);
680 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
681 arg.flags = (sk && inet_sk(sk)->transparent) ? IP_REPLY_ARG_NOSRCCHECK : 0;
682 /* When socket is gone, all binding information is lost.
683 * routing might fail in this case. No choice here, if we choose to force
684 * input interface, we will misroute in case of asymmetric route.
687 arg.bound_dev_if = sk->sk_bound_dev_if;
689 arg.tos = ip_hdr(skb)->tos;
690 ip_send_unicast_reply(*this_cpu_ptr(net->ipv4.tcp_sk),
691 skb, &TCP_SKB_CB(skb)->header.h4.opt,
692 ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
693 &arg, arg.iov[0].iov_len);
695 TCP_INC_STATS_BH(net, TCP_MIB_OUTSEGS);
696 TCP_INC_STATS_BH(net, TCP_MIB_OUTRSTS);
698 #ifdef CONFIG_TCP_MD5SIG
707 /* The code following below sending ACKs in SYN-RECV and TIME-WAIT states
708 outside socket context is ugly, certainly. What can I do?
711 static void tcp_v4_send_ack(struct net *net,
712 struct sk_buff *skb, u32 seq, u32 ack,
713 u32 win, u32 tsval, u32 tsecr, int oif,
714 struct tcp_md5sig_key *key,
715 int reply_flags, u8 tos)
717 const struct tcphdr *th = tcp_hdr(skb);
720 __be32 opt[(TCPOLEN_TSTAMP_ALIGNED >> 2)
721 #ifdef CONFIG_TCP_MD5SIG
722 + (TCPOLEN_MD5SIG_ALIGNED >> 2)
726 struct ip_reply_arg arg;
728 memset(&rep.th, 0, sizeof(struct tcphdr));
729 memset(&arg, 0, sizeof(arg));
731 arg.iov[0].iov_base = (unsigned char *)&rep;
732 arg.iov[0].iov_len = sizeof(rep.th);
734 rep.opt[0] = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
735 (TCPOPT_TIMESTAMP << 8) |
737 rep.opt[1] = htonl(tsval);
738 rep.opt[2] = htonl(tsecr);
739 arg.iov[0].iov_len += TCPOLEN_TSTAMP_ALIGNED;
742 /* Swap the send and the receive. */
743 rep.th.dest = th->source;
744 rep.th.source = th->dest;
745 rep.th.doff = arg.iov[0].iov_len / 4;
746 rep.th.seq = htonl(seq);
747 rep.th.ack_seq = htonl(ack);
749 rep.th.window = htons(win);
751 #ifdef CONFIG_TCP_MD5SIG
753 int offset = (tsecr) ? 3 : 0;
755 rep.opt[offset++] = htonl((TCPOPT_NOP << 24) |
757 (TCPOPT_MD5SIG << 8) |
759 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED;
760 rep.th.doff = arg.iov[0].iov_len/4;
762 tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[offset],
763 key, ip_hdr(skb)->saddr,
764 ip_hdr(skb)->daddr, &rep.th);
767 arg.flags = reply_flags;
768 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
769 ip_hdr(skb)->saddr, /* XXX */
770 arg.iov[0].iov_len, IPPROTO_TCP, 0);
771 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
773 arg.bound_dev_if = oif;
775 ip_send_unicast_reply(*this_cpu_ptr(net->ipv4.tcp_sk),
776 skb, &TCP_SKB_CB(skb)->header.h4.opt,
777 ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
778 &arg, arg.iov[0].iov_len);
780 TCP_INC_STATS_BH(net, TCP_MIB_OUTSEGS);
783 static void tcp_v4_timewait_ack(struct sock *sk, struct sk_buff *skb)
785 struct inet_timewait_sock *tw = inet_twsk(sk);
786 struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
788 tcp_v4_send_ack(sock_net(sk), skb,
789 tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
790 tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
791 tcp_time_stamp + tcptw->tw_ts_offset,
794 tcp_twsk_md5_key(tcptw),
795 tw->tw_transparent ? IP_REPLY_ARG_NOSRCCHECK : 0,
802 static void tcp_v4_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb,
803 struct request_sock *req)
805 /* sk->sk_state == TCP_LISTEN -> for regular TCP_SYN_RECV
806 * sk->sk_state == TCP_SYN_RECV -> for Fast Open.
808 u32 seq = (sk->sk_state == TCP_LISTEN) ? tcp_rsk(req)->snt_isn + 1 :
811 tcp_v4_send_ack(sock_net(sk), skb, seq,
812 tcp_rsk(req)->rcv_nxt, req->rsk_rcv_wnd,
816 tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&ip_hdr(skb)->daddr,
818 inet_rsk(req)->no_srccheck ? IP_REPLY_ARG_NOSRCCHECK : 0,
823 * Send a SYN-ACK after having received a SYN.
824 * This still operates on a request_sock only, not on a big
827 static int tcp_v4_send_synack(const struct sock *sk, struct dst_entry *dst,
829 struct request_sock *req,
830 struct tcp_fastopen_cookie *foc,
833 const struct inet_request_sock *ireq = inet_rsk(req);
838 /* First, grab a route. */
839 if (!dst && (dst = inet_csk_route_req(sk, &fl4, req)) == NULL)
842 skb = tcp_make_synack(sk, dst, req, foc, attach_req);
845 __tcp_v4_send_check(skb, ireq->ir_loc_addr, ireq->ir_rmt_addr);
847 err = ip_build_and_send_pkt(skb, sk, ireq->ir_loc_addr,
850 err = net_xmit_eval(err);
857 * IPv4 request_sock destructor.
859 static void tcp_v4_reqsk_destructor(struct request_sock *req)
861 kfree(inet_rsk(req)->opt);
865 #ifdef CONFIG_TCP_MD5SIG
867 * RFC2385 MD5 checksumming requires a mapping of
868 * IP address->MD5 Key.
869 * We need to maintain these in the sk structure.
872 /* Find the Key structure for an address. */
873 struct tcp_md5sig_key *tcp_md5_do_lookup(const struct sock *sk,
874 const union tcp_md5_addr *addr,
877 const struct tcp_sock *tp = tcp_sk(sk);
878 struct tcp_md5sig_key *key;
879 unsigned int size = sizeof(struct in_addr);
880 const struct tcp_md5sig_info *md5sig;
882 /* caller either holds rcu_read_lock() or socket lock */
883 md5sig = rcu_dereference_check(tp->md5sig_info,
884 sock_owned_by_user(sk) ||
885 lockdep_is_held((spinlock_t *)&sk->sk_lock.slock));
888 #if IS_ENABLED(CONFIG_IPV6)
889 if (family == AF_INET6)
890 size = sizeof(struct in6_addr);
892 hlist_for_each_entry_rcu(key, &md5sig->head, node) {
893 if (key->family != family)
895 if (!memcmp(&key->addr, addr, size))
900 EXPORT_SYMBOL(tcp_md5_do_lookup);
902 struct tcp_md5sig_key *tcp_v4_md5_lookup(const struct sock *sk,
903 const struct sock *addr_sk)
905 const union tcp_md5_addr *addr;
907 addr = (const union tcp_md5_addr *)&addr_sk->sk_daddr;
908 return tcp_md5_do_lookup(sk, addr, AF_INET);
910 EXPORT_SYMBOL(tcp_v4_md5_lookup);
912 /* This can be called on a newly created socket, from other files */
913 int tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr,
914 int family, const u8 *newkey, u8 newkeylen, gfp_t gfp)
916 /* Add Key to the list */
917 struct tcp_md5sig_key *key;
918 struct tcp_sock *tp = tcp_sk(sk);
919 struct tcp_md5sig_info *md5sig;
921 key = tcp_md5_do_lookup(sk, addr, family);
923 /* Pre-existing entry - just update that one. */
924 memcpy(key->key, newkey, newkeylen);
925 key->keylen = newkeylen;
929 md5sig = rcu_dereference_protected(tp->md5sig_info,
930 sock_owned_by_user(sk) ||
931 lockdep_is_held(&sk->sk_lock.slock));
933 md5sig = kmalloc(sizeof(*md5sig), gfp);
937 sk_nocaps_add(sk, NETIF_F_GSO_MASK);
938 INIT_HLIST_HEAD(&md5sig->head);
939 rcu_assign_pointer(tp->md5sig_info, md5sig);
942 key = sock_kmalloc(sk, sizeof(*key), gfp);
945 if (!tcp_alloc_md5sig_pool()) {
946 sock_kfree_s(sk, key, sizeof(*key));
950 memcpy(key->key, newkey, newkeylen);
951 key->keylen = newkeylen;
952 key->family = family;
953 memcpy(&key->addr, addr,
954 (family == AF_INET6) ? sizeof(struct in6_addr) :
955 sizeof(struct in_addr));
956 hlist_add_head_rcu(&key->node, &md5sig->head);
959 EXPORT_SYMBOL(tcp_md5_do_add);
961 int tcp_md5_do_del(struct sock *sk, const union tcp_md5_addr *addr, int family)
963 struct tcp_md5sig_key *key;
965 key = tcp_md5_do_lookup(sk, addr, family);
968 hlist_del_rcu(&key->node);
969 atomic_sub(sizeof(*key), &sk->sk_omem_alloc);
973 EXPORT_SYMBOL(tcp_md5_do_del);
975 static void tcp_clear_md5_list(struct sock *sk)
977 struct tcp_sock *tp = tcp_sk(sk);
978 struct tcp_md5sig_key *key;
979 struct hlist_node *n;
980 struct tcp_md5sig_info *md5sig;
982 md5sig = rcu_dereference_protected(tp->md5sig_info, 1);
984 hlist_for_each_entry_safe(key, n, &md5sig->head, node) {
985 hlist_del_rcu(&key->node);
986 atomic_sub(sizeof(*key), &sk->sk_omem_alloc);
991 static int tcp_v4_parse_md5_keys(struct sock *sk, char __user *optval,
994 struct tcp_md5sig cmd;
995 struct sockaddr_in *sin = (struct sockaddr_in *)&cmd.tcpm_addr;
997 if (optlen < sizeof(cmd))
1000 if (copy_from_user(&cmd, optval, sizeof(cmd)))
1003 if (sin->sin_family != AF_INET)
1006 if (!cmd.tcpm_keylen)
1007 return tcp_md5_do_del(sk, (union tcp_md5_addr *)&sin->sin_addr.s_addr,
1010 if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN)
1013 return tcp_md5_do_add(sk, (union tcp_md5_addr *)&sin->sin_addr.s_addr,
1014 AF_INET, cmd.tcpm_key, cmd.tcpm_keylen,
1018 static int tcp_v4_md5_hash_pseudoheader(struct tcp_md5sig_pool *hp,
1019 __be32 daddr, __be32 saddr, int nbytes)
1021 struct tcp4_pseudohdr *bp;
1022 struct scatterlist sg;
1024 bp = &hp->md5_blk.ip4;
1027 * 1. the TCP pseudo-header (in the order: source IP address,
1028 * destination IP address, zero-padded protocol number, and
1034 bp->protocol = IPPROTO_TCP;
1035 bp->len = cpu_to_be16(nbytes);
1037 sg_init_one(&sg, bp, sizeof(*bp));
1038 return crypto_hash_update(&hp->md5_desc, &sg, sizeof(*bp));
1041 static int tcp_v4_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key,
1042 __be32 daddr, __be32 saddr, const struct tcphdr *th)
1044 struct tcp_md5sig_pool *hp;
1045 struct hash_desc *desc;
1047 hp = tcp_get_md5sig_pool();
1049 goto clear_hash_noput;
1050 desc = &hp->md5_desc;
1052 if (crypto_hash_init(desc))
1054 if (tcp_v4_md5_hash_pseudoheader(hp, daddr, saddr, th->doff << 2))
1056 if (tcp_md5_hash_header(hp, th))
1058 if (tcp_md5_hash_key(hp, key))
1060 if (crypto_hash_final(desc, md5_hash))
1063 tcp_put_md5sig_pool();
1067 tcp_put_md5sig_pool();
1069 memset(md5_hash, 0, 16);
1073 int tcp_v4_md5_hash_skb(char *md5_hash, const struct tcp_md5sig_key *key,
1074 const struct sock *sk,
1075 const struct sk_buff *skb)
1077 struct tcp_md5sig_pool *hp;
1078 struct hash_desc *desc;
1079 const struct tcphdr *th = tcp_hdr(skb);
1080 __be32 saddr, daddr;
1082 if (sk) { /* valid for establish/request sockets */
1083 saddr = sk->sk_rcv_saddr;
1084 daddr = sk->sk_daddr;
1086 const struct iphdr *iph = ip_hdr(skb);
1091 hp = tcp_get_md5sig_pool();
1093 goto clear_hash_noput;
1094 desc = &hp->md5_desc;
1096 if (crypto_hash_init(desc))
1099 if (tcp_v4_md5_hash_pseudoheader(hp, daddr, saddr, skb->len))
1101 if (tcp_md5_hash_header(hp, th))
1103 if (tcp_md5_hash_skb_data(hp, skb, th->doff << 2))
1105 if (tcp_md5_hash_key(hp, key))
1107 if (crypto_hash_final(desc, md5_hash))
1110 tcp_put_md5sig_pool();
1114 tcp_put_md5sig_pool();
1116 memset(md5_hash, 0, 16);
1119 EXPORT_SYMBOL(tcp_v4_md5_hash_skb);
1123 /* Called with rcu_read_lock() */
1124 static bool tcp_v4_inbound_md5_hash(const struct sock *sk,
1125 const struct sk_buff *skb)
1127 #ifdef CONFIG_TCP_MD5SIG
1129 * This gets called for each TCP segment that arrives
1130 * so we want to be efficient.
1131 * We have 3 drop cases:
1132 * o No MD5 hash and one expected.
1133 * o MD5 hash and we're not expecting one.
1134 * o MD5 hash and its wrong.
1136 const __u8 *hash_location = NULL;
1137 struct tcp_md5sig_key *hash_expected;
1138 const struct iphdr *iph = ip_hdr(skb);
1139 const struct tcphdr *th = tcp_hdr(skb);
1141 unsigned char newhash[16];
1143 hash_expected = tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&iph->saddr,
1145 hash_location = tcp_parse_md5sig_option(th);
1147 /* We've parsed the options - do we have a hash? */
1148 if (!hash_expected && !hash_location)
1151 if (hash_expected && !hash_location) {
1152 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5NOTFOUND);
1156 if (!hash_expected && hash_location) {
1157 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5UNEXPECTED);
1161 /* Okay, so this is hash_expected and hash_location -
1162 * so we need to calculate the checksum.
1164 genhash = tcp_v4_md5_hash_skb(newhash,
1168 if (genhash || memcmp(hash_location, newhash, 16) != 0) {
1169 net_info_ratelimited("MD5 Hash failed for (%pI4, %d)->(%pI4, %d)%s\n",
1170 &iph->saddr, ntohs(th->source),
1171 &iph->daddr, ntohs(th->dest),
1172 genhash ? " tcp_v4_calc_md5_hash failed"
1181 static void tcp_v4_init_req(struct request_sock *req,
1182 const struct sock *sk_listener,
1183 struct sk_buff *skb)
1185 struct inet_request_sock *ireq = inet_rsk(req);
1187 sk_rcv_saddr_set(req_to_sk(req), ip_hdr(skb)->daddr);
1188 sk_daddr_set(req_to_sk(req), ip_hdr(skb)->saddr);
1189 ireq->no_srccheck = inet_sk(sk_listener)->transparent;
1190 ireq->opt = tcp_v4_save_options(skb);
1193 static struct dst_entry *tcp_v4_route_req(const struct sock *sk,
1195 const struct request_sock *req,
1198 struct dst_entry *dst = inet_csk_route_req(sk, &fl->u.ip4, req);
1201 if (fl->u.ip4.daddr == inet_rsk(req)->ir_rmt_addr)
1210 struct request_sock_ops tcp_request_sock_ops __read_mostly = {
1212 .obj_size = sizeof(struct tcp_request_sock),
1213 .rtx_syn_ack = tcp_rtx_synack,
1214 .send_ack = tcp_v4_reqsk_send_ack,
1215 .destructor = tcp_v4_reqsk_destructor,
1216 .send_reset = tcp_v4_send_reset,
1217 .syn_ack_timeout = tcp_syn_ack_timeout,
1220 static const struct tcp_request_sock_ops tcp_request_sock_ipv4_ops = {
1221 .mss_clamp = TCP_MSS_DEFAULT,
1222 #ifdef CONFIG_TCP_MD5SIG
1223 .req_md5_lookup = tcp_v4_md5_lookup,
1224 .calc_md5_hash = tcp_v4_md5_hash_skb,
1226 .init_req = tcp_v4_init_req,
1227 #ifdef CONFIG_SYN_COOKIES
1228 .cookie_init_seq = cookie_v4_init_sequence,
1230 .route_req = tcp_v4_route_req,
1231 .init_seq = tcp_v4_init_sequence,
1232 .send_synack = tcp_v4_send_synack,
1235 int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
1237 /* Never answer to SYNs send to broadcast or multicast */
1238 if (skb_rtable(skb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
1241 return tcp_conn_request(&tcp_request_sock_ops,
1242 &tcp_request_sock_ipv4_ops, sk, skb);
1245 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
1248 EXPORT_SYMBOL(tcp_v4_conn_request);
1252 * The three way handshake has completed - we got a valid synack -
1253 * now create the new socket.
1255 struct sock *tcp_v4_syn_recv_sock(const struct sock *sk, struct sk_buff *skb,
1256 struct request_sock *req,
1257 struct dst_entry *dst,
1258 struct request_sock *req_unhash,
1261 struct inet_request_sock *ireq;
1262 struct inet_sock *newinet;
1263 struct tcp_sock *newtp;
1265 #ifdef CONFIG_TCP_MD5SIG
1266 struct tcp_md5sig_key *key;
1268 struct ip_options_rcu *inet_opt;
1270 if (sk_acceptq_is_full(sk))
1273 newsk = tcp_create_openreq_child(sk, req, skb);
1277 newsk->sk_gso_type = SKB_GSO_TCPV4;
1278 inet_sk_rx_dst_set(newsk, skb);
1280 newtp = tcp_sk(newsk);
1281 newinet = inet_sk(newsk);
1282 ireq = inet_rsk(req);
1283 sk_daddr_set(newsk, ireq->ir_rmt_addr);
1284 sk_rcv_saddr_set(newsk, ireq->ir_loc_addr);
1285 newinet->inet_saddr = ireq->ir_loc_addr;
1286 inet_opt = ireq->opt;
1287 rcu_assign_pointer(newinet->inet_opt, inet_opt);
1289 newinet->mc_index = inet_iif(skb);
1290 newinet->mc_ttl = ip_hdr(skb)->ttl;
1291 newinet->rcv_tos = ip_hdr(skb)->tos;
1292 inet_csk(newsk)->icsk_ext_hdr_len = 0;
1294 inet_csk(newsk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
1295 newinet->inet_id = newtp->write_seq ^ jiffies;
1298 dst = inet_csk_route_child_sock(sk, newsk, req);
1302 /* syncookie case : see end of cookie_v4_check() */
1304 sk_setup_caps(newsk, dst);
1306 tcp_ca_openreq_child(newsk, dst);
1308 tcp_sync_mss(newsk, dst_mtu(dst));
1309 newtp->advmss = dst_metric_advmss(dst);
1310 if (tcp_sk(sk)->rx_opt.user_mss &&
1311 tcp_sk(sk)->rx_opt.user_mss < newtp->advmss)
1312 newtp->advmss = tcp_sk(sk)->rx_opt.user_mss;
1314 tcp_initialize_rcv_mss(newsk);
1316 #ifdef CONFIG_TCP_MD5SIG
1317 /* Copy over the MD5 key from the original socket */
1318 key = tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&newinet->inet_daddr,
1322 * We're using one, so create a matching key
1323 * on the newsk structure. If we fail to get
1324 * memory, then we end up not copying the key
1327 tcp_md5_do_add(newsk, (union tcp_md5_addr *)&newinet->inet_daddr,
1328 AF_INET, key->key, key->keylen, GFP_ATOMIC);
1329 sk_nocaps_add(newsk, NETIF_F_GSO_MASK);
1333 if (__inet_inherit_port(sk, newsk) < 0)
1335 *own_req = inet_ehash_nolisten(newsk, req_to_sk(req_unhash));
1337 tcp_move_syn(newtp, req);
1342 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
1346 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
1349 inet_csk_prepare_forced_close(newsk);
1353 EXPORT_SYMBOL(tcp_v4_syn_recv_sock);
1355 static struct sock *tcp_v4_cookie_check(struct sock *sk, struct sk_buff *skb)
1357 #ifdef CONFIG_SYN_COOKIES
1358 const struct tcphdr *th = tcp_hdr(skb);
1361 sk = cookie_v4_check(sk, skb);
1366 /* The socket must have it's spinlock held when we get
1367 * here, unless it is a TCP_LISTEN socket.
1369 * We have a potential double-lock case here, so even when
1370 * doing backlog processing we use the BH locking scheme.
1371 * This is because we cannot sleep with the original spinlock
1374 int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
1378 if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
1379 struct dst_entry *dst = sk->sk_rx_dst;
1381 sock_rps_save_rxhash(sk, skb);
1382 sk_mark_napi_id(sk, skb);
1384 if (inet_sk(sk)->rx_dst_ifindex != skb->skb_iif ||
1385 !dst->ops->check(dst, 0)) {
1387 sk->sk_rx_dst = NULL;
1390 tcp_rcv_established(sk, skb, tcp_hdr(skb), skb->len);
1394 if (tcp_checksum_complete(skb))
1397 if (sk->sk_state == TCP_LISTEN) {
1398 struct sock *nsk = tcp_v4_cookie_check(sk, skb);
1403 sock_rps_save_rxhash(nsk, skb);
1404 sk_mark_napi_id(nsk, skb);
1405 if (tcp_child_process(sk, nsk, skb)) {
1412 sock_rps_save_rxhash(sk, skb);
1414 if (tcp_rcv_state_process(sk, skb)) {
1421 tcp_v4_send_reset(rsk, skb);
1424 /* Be careful here. If this function gets more complicated and
1425 * gcc suffers from register pressure on the x86, sk (in %ebx)
1426 * might be destroyed here. This current version compiles correctly,
1427 * but you have been warned.
1432 TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_CSUMERRORS);
1433 TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_INERRS);
1436 EXPORT_SYMBOL(tcp_v4_do_rcv);
1438 void tcp_v4_early_demux(struct sk_buff *skb)
1440 const struct iphdr *iph;
1441 const struct tcphdr *th;
1444 if (skb->pkt_type != PACKET_HOST)
1447 if (!pskb_may_pull(skb, skb_transport_offset(skb) + sizeof(struct tcphdr)))
1453 if (th->doff < sizeof(struct tcphdr) / 4)
1456 sk = __inet_lookup_established(dev_net(skb->dev), &tcp_hashinfo,
1457 iph->saddr, th->source,
1458 iph->daddr, ntohs(th->dest),
1462 skb->destructor = sock_edemux;
1463 if (sk_fullsock(sk)) {
1464 struct dst_entry *dst = READ_ONCE(sk->sk_rx_dst);
1467 dst = dst_check(dst, 0);
1469 inet_sk(sk)->rx_dst_ifindex == skb->skb_iif)
1470 skb_dst_set_noref(skb, dst);
1475 /* Packet is added to VJ-style prequeue for processing in process
1476 * context, if a reader task is waiting. Apparently, this exciting
1477 * idea (VJ's mail "Re: query about TCP header on tcp-ip" of 07 Sep 93)
1478 * failed somewhere. Latency? Burstiness? Well, at least now we will
1479 * see, why it failed. 8)8) --ANK
1482 bool tcp_prequeue(struct sock *sk, struct sk_buff *skb)
1484 struct tcp_sock *tp = tcp_sk(sk);
1486 if (sysctl_tcp_low_latency || !tp->ucopy.task)
1489 if (skb->len <= tcp_hdrlen(skb) &&
1490 skb_queue_len(&tp->ucopy.prequeue) == 0)
1493 /* Before escaping RCU protected region, we need to take care of skb
1494 * dst. Prequeue is only enabled for established sockets.
1495 * For such sockets, we might need the skb dst only to set sk->sk_rx_dst
1496 * Instead of doing full sk_rx_dst validity here, let's perform
1497 * an optimistic check.
1499 if (likely(sk->sk_rx_dst))
1502 skb_dst_force_safe(skb);
1504 __skb_queue_tail(&tp->ucopy.prequeue, skb);
1505 tp->ucopy.memory += skb->truesize;
1506 if (tp->ucopy.memory > sk->sk_rcvbuf) {
1507 struct sk_buff *skb1;
1509 BUG_ON(sock_owned_by_user(sk));
1511 while ((skb1 = __skb_dequeue(&tp->ucopy.prequeue)) != NULL) {
1512 sk_backlog_rcv(sk, skb1);
1513 NET_INC_STATS_BH(sock_net(sk),
1514 LINUX_MIB_TCPPREQUEUEDROPPED);
1517 tp->ucopy.memory = 0;
1518 } else if (skb_queue_len(&tp->ucopy.prequeue) == 1) {
1519 wake_up_interruptible_sync_poll(sk_sleep(sk),
1520 POLLIN | POLLRDNORM | POLLRDBAND);
1521 if (!inet_csk_ack_scheduled(sk))
1522 inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK,
1523 (3 * tcp_rto_min(sk)) / 4,
1528 EXPORT_SYMBOL(tcp_prequeue);
1534 int tcp_v4_rcv(struct sk_buff *skb)
1536 const struct iphdr *iph;
1537 const struct tcphdr *th;
1540 struct net *net = dev_net(skb->dev);
1542 if (skb->pkt_type != PACKET_HOST)
1545 /* Count it even if it's bad */
1546 TCP_INC_STATS_BH(net, TCP_MIB_INSEGS);
1548 if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
1553 if (th->doff < sizeof(struct tcphdr) / 4)
1555 if (!pskb_may_pull(skb, th->doff * 4))
1558 /* An explanation is required here, I think.
1559 * Packet length and doff are validated by header prediction,
1560 * provided case of th->doff==0 is eliminated.
1561 * So, we defer the checks. */
1563 if (skb_checksum_init(skb, IPPROTO_TCP, inet_compute_pseudo))
1568 /* This is tricky : We move IPCB at its correct location into TCP_SKB_CB()
1569 * barrier() makes sure compiler wont play fool^Waliasing games.
1571 memmove(&TCP_SKB_CB(skb)->header.h4, IPCB(skb),
1572 sizeof(struct inet_skb_parm));
1575 TCP_SKB_CB(skb)->seq = ntohl(th->seq);
1576 TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
1577 skb->len - th->doff * 4);
1578 TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
1579 TCP_SKB_CB(skb)->tcp_flags = tcp_flag_byte(th);
1580 TCP_SKB_CB(skb)->tcp_tw_isn = 0;
1581 TCP_SKB_CB(skb)->ip_dsfield = ipv4_get_dsfield(iph);
1582 TCP_SKB_CB(skb)->sacked = 0;
1585 sk = __inet_lookup_skb(&tcp_hashinfo, skb, th->source, th->dest);
1590 if (sk->sk_state == TCP_TIME_WAIT)
1593 if (sk->sk_state == TCP_NEW_SYN_RECV) {
1594 struct request_sock *req = inet_reqsk(sk);
1597 sk = req->rsk_listener;
1598 if (unlikely(tcp_v4_inbound_md5_hash(sk, skb))) {
1602 if (unlikely(sk->sk_state != TCP_LISTEN)) {
1603 inet_csk_reqsk_queue_drop_and_put(sk, req);
1607 nsk = tcp_check_req(sk, skb, req, false);
1610 goto discard_and_relse;
1614 } else if (tcp_child_process(sk, nsk, skb)) {
1615 tcp_v4_send_reset(nsk, skb);
1616 goto discard_and_relse;
1622 if (unlikely(iph->ttl < inet_sk(sk)->min_ttl)) {
1623 NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP);
1624 goto discard_and_relse;
1627 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
1628 goto discard_and_relse;
1630 if (tcp_v4_inbound_md5_hash(sk, skb))
1631 goto discard_and_relse;
1635 if (sk_filter(sk, skb))
1636 goto discard_and_relse;
1640 if (sk->sk_state == TCP_LISTEN) {
1641 ret = tcp_v4_do_rcv(sk, skb);
1642 goto put_and_return;
1645 sk_incoming_cpu_update(sk);
1647 bh_lock_sock_nested(sk);
1648 tcp_sk(sk)->segs_in += max_t(u16, 1, skb_shinfo(skb)->gso_segs);
1650 if (!sock_owned_by_user(sk)) {
1651 if (!tcp_prequeue(sk, skb))
1652 ret = tcp_v4_do_rcv(sk, skb);
1653 } else if (unlikely(sk_add_backlog(sk, skb,
1654 sk->sk_rcvbuf + sk->sk_sndbuf))) {
1656 NET_INC_STATS_BH(net, LINUX_MIB_TCPBACKLOGDROP);
1657 goto discard_and_relse;
1667 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
1670 if (tcp_checksum_complete(skb)) {
1672 TCP_INC_STATS_BH(net, TCP_MIB_CSUMERRORS);
1674 TCP_INC_STATS_BH(net, TCP_MIB_INERRS);
1676 tcp_v4_send_reset(NULL, skb);
1680 /* Discard frame. */
1689 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
1690 inet_twsk_put(inet_twsk(sk));
1694 if (tcp_checksum_complete(skb)) {
1695 inet_twsk_put(inet_twsk(sk));
1698 switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) {
1700 struct sock *sk2 = inet_lookup_listener(dev_net(skb->dev),
1702 iph->saddr, th->source,
1703 iph->daddr, th->dest,
1706 inet_twsk_deschedule_put(inet_twsk(sk));
1710 /* Fall through to ACK */
1713 tcp_v4_timewait_ack(sk, skb);
1717 case TCP_TW_SUCCESS:;
1722 static struct timewait_sock_ops tcp_timewait_sock_ops = {
1723 .twsk_obj_size = sizeof(struct tcp_timewait_sock),
1724 .twsk_unique = tcp_twsk_unique,
1725 .twsk_destructor= tcp_twsk_destructor,
1728 void inet_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb)
1730 struct dst_entry *dst = skb_dst(skb);
1732 if (dst && dst_hold_safe(dst)) {
1733 sk->sk_rx_dst = dst;
1734 inet_sk(sk)->rx_dst_ifindex = skb->skb_iif;
1737 EXPORT_SYMBOL(inet_sk_rx_dst_set);
1739 const struct inet_connection_sock_af_ops ipv4_specific = {
1740 .queue_xmit = ip_queue_xmit,
1741 .send_check = tcp_v4_send_check,
1742 .rebuild_header = inet_sk_rebuild_header,
1743 .sk_rx_dst_set = inet_sk_rx_dst_set,
1744 .conn_request = tcp_v4_conn_request,
1745 .syn_recv_sock = tcp_v4_syn_recv_sock,
1746 .net_header_len = sizeof(struct iphdr),
1747 .setsockopt = ip_setsockopt,
1748 .getsockopt = ip_getsockopt,
1749 .addr2sockaddr = inet_csk_addr2sockaddr,
1750 .sockaddr_len = sizeof(struct sockaddr_in),
1751 .bind_conflict = inet_csk_bind_conflict,
1752 #ifdef CONFIG_COMPAT
1753 .compat_setsockopt = compat_ip_setsockopt,
1754 .compat_getsockopt = compat_ip_getsockopt,
1756 .mtu_reduced = tcp_v4_mtu_reduced,
1758 EXPORT_SYMBOL(ipv4_specific);
1760 #ifdef CONFIG_TCP_MD5SIG
1761 static const struct tcp_sock_af_ops tcp_sock_ipv4_specific = {
1762 .md5_lookup = tcp_v4_md5_lookup,
1763 .calc_md5_hash = tcp_v4_md5_hash_skb,
1764 .md5_parse = tcp_v4_parse_md5_keys,
1768 /* NOTE: A lot of things set to zero explicitly by call to
1769 * sk_alloc() so need not be done here.
1771 static int tcp_v4_init_sock(struct sock *sk)
1773 struct inet_connection_sock *icsk = inet_csk(sk);
1777 icsk->icsk_af_ops = &ipv4_specific;
1779 #ifdef CONFIG_TCP_MD5SIG
1780 tcp_sk(sk)->af_specific = &tcp_sock_ipv4_specific;
1786 void tcp_v4_destroy_sock(struct sock *sk)
1788 struct tcp_sock *tp = tcp_sk(sk);
1790 tcp_clear_xmit_timers(sk);
1792 tcp_cleanup_congestion_control(sk);
1794 /* Cleanup up the write buffer. */
1795 tcp_write_queue_purge(sk);
1797 /* Cleans up our, hopefully empty, out_of_order_queue. */
1798 __skb_queue_purge(&tp->out_of_order_queue);
1800 #ifdef CONFIG_TCP_MD5SIG
1801 /* Clean up the MD5 key list, if any */
1802 if (tp->md5sig_info) {
1803 tcp_clear_md5_list(sk);
1804 kfree_rcu(tp->md5sig_info, rcu);
1805 tp->md5sig_info = NULL;
1809 /* Clean prequeue, it must be empty really */
1810 __skb_queue_purge(&tp->ucopy.prequeue);
1812 /* Clean up a referenced TCP bind bucket. */
1813 if (inet_csk(sk)->icsk_bind_hash)
1816 BUG_ON(tp->fastopen_rsk);
1818 /* If socket is aborted during connect operation */
1819 tcp_free_fastopen_req(tp);
1820 tcp_saved_syn_free(tp);
1822 sk_sockets_allocated_dec(sk);
1823 sock_release_memcg(sk);
1825 EXPORT_SYMBOL(tcp_v4_destroy_sock);
1827 #ifdef CONFIG_PROC_FS
1828 /* Proc filesystem TCP sock list dumping. */
1831 * Get next listener socket follow cur. If cur is NULL, get first socket
1832 * starting from bucket given in st->bucket; when st->bucket is zero the
1833 * very first socket in the hash table is returned.
1835 static void *listening_get_next(struct seq_file *seq, void *cur)
1837 struct inet_connection_sock *icsk;
1838 struct hlist_nulls_node *node;
1839 struct sock *sk = cur;
1840 struct inet_listen_hashbucket *ilb;
1841 struct tcp_iter_state *st = seq->private;
1842 struct net *net = seq_file_net(seq);
1845 ilb = &tcp_hashinfo.listening_hash[st->bucket];
1846 spin_lock_bh(&ilb->lock);
1847 sk = sk_nulls_head(&ilb->head);
1851 ilb = &tcp_hashinfo.listening_hash[st->bucket];
1855 sk = sk_nulls_next(sk);
1857 sk_nulls_for_each_from(sk, node) {
1858 if (!net_eq(sock_net(sk), net))
1860 if (sk->sk_family == st->family) {
1864 icsk = inet_csk(sk);
1866 spin_unlock_bh(&ilb->lock);
1868 if (++st->bucket < INET_LHTABLE_SIZE) {
1869 ilb = &tcp_hashinfo.listening_hash[st->bucket];
1870 spin_lock_bh(&ilb->lock);
1871 sk = sk_nulls_head(&ilb->head);
1879 static void *listening_get_idx(struct seq_file *seq, loff_t *pos)
1881 struct tcp_iter_state *st = seq->private;
1886 rc = listening_get_next(seq, NULL);
1888 while (rc && *pos) {
1889 rc = listening_get_next(seq, rc);
1895 static inline bool empty_bucket(const struct tcp_iter_state *st)
1897 return hlist_nulls_empty(&tcp_hashinfo.ehash[st->bucket].chain);
1901 * Get first established socket starting from bucket given in st->bucket.
1902 * If st->bucket is zero, the very first socket in the hash is returned.
1904 static void *established_get_first(struct seq_file *seq)
1906 struct tcp_iter_state *st = seq->private;
1907 struct net *net = seq_file_net(seq);
1911 for (; st->bucket <= tcp_hashinfo.ehash_mask; ++st->bucket) {
1913 struct hlist_nulls_node *node;
1914 spinlock_t *lock = inet_ehash_lockp(&tcp_hashinfo, st->bucket);
1916 /* Lockless fast path for the common case of empty buckets */
1917 if (empty_bucket(st))
1921 sk_nulls_for_each(sk, node, &tcp_hashinfo.ehash[st->bucket].chain) {
1922 if (sk->sk_family != st->family ||
1923 !net_eq(sock_net(sk), net)) {
1929 spin_unlock_bh(lock);
1935 static void *established_get_next(struct seq_file *seq, void *cur)
1937 struct sock *sk = cur;
1938 struct hlist_nulls_node *node;
1939 struct tcp_iter_state *st = seq->private;
1940 struct net *net = seq_file_net(seq);
1945 sk = sk_nulls_next(sk);
1947 sk_nulls_for_each_from(sk, node) {
1948 if (sk->sk_family == st->family && net_eq(sock_net(sk), net))
1952 spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
1954 return established_get_first(seq);
1957 static void *established_get_idx(struct seq_file *seq, loff_t pos)
1959 struct tcp_iter_state *st = seq->private;
1963 rc = established_get_first(seq);
1966 rc = established_get_next(seq, rc);
1972 static void *tcp_get_idx(struct seq_file *seq, loff_t pos)
1975 struct tcp_iter_state *st = seq->private;
1977 st->state = TCP_SEQ_STATE_LISTENING;
1978 rc = listening_get_idx(seq, &pos);
1981 st->state = TCP_SEQ_STATE_ESTABLISHED;
1982 rc = established_get_idx(seq, pos);
1988 static void *tcp_seek_last_pos(struct seq_file *seq)
1990 struct tcp_iter_state *st = seq->private;
1991 int offset = st->offset;
1992 int orig_num = st->num;
1995 switch (st->state) {
1996 case TCP_SEQ_STATE_LISTENING:
1997 if (st->bucket >= INET_LHTABLE_SIZE)
1999 st->state = TCP_SEQ_STATE_LISTENING;
2000 rc = listening_get_next(seq, NULL);
2001 while (offset-- && rc)
2002 rc = listening_get_next(seq, rc);
2006 st->state = TCP_SEQ_STATE_ESTABLISHED;
2008 case TCP_SEQ_STATE_ESTABLISHED:
2009 if (st->bucket > tcp_hashinfo.ehash_mask)
2011 rc = established_get_first(seq);
2012 while (offset-- && rc)
2013 rc = established_get_next(seq, rc);
2021 static void *tcp_seq_start(struct seq_file *seq, loff_t *pos)
2023 struct tcp_iter_state *st = seq->private;
2026 if (*pos && *pos == st->last_pos) {
2027 rc = tcp_seek_last_pos(seq);
2032 st->state = TCP_SEQ_STATE_LISTENING;
2036 rc = *pos ? tcp_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
2039 st->last_pos = *pos;
2043 static void *tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2045 struct tcp_iter_state *st = seq->private;
2048 if (v == SEQ_START_TOKEN) {
2049 rc = tcp_get_idx(seq, 0);
2053 switch (st->state) {
2054 case TCP_SEQ_STATE_LISTENING:
2055 rc = listening_get_next(seq, v);
2057 st->state = TCP_SEQ_STATE_ESTABLISHED;
2060 rc = established_get_first(seq);
2063 case TCP_SEQ_STATE_ESTABLISHED:
2064 rc = established_get_next(seq, v);
2069 st->last_pos = *pos;
2073 static void tcp_seq_stop(struct seq_file *seq, void *v)
2075 struct tcp_iter_state *st = seq->private;
2077 switch (st->state) {
2078 case TCP_SEQ_STATE_LISTENING:
2079 if (v != SEQ_START_TOKEN)
2080 spin_unlock_bh(&tcp_hashinfo.listening_hash[st->bucket].lock);
2082 case TCP_SEQ_STATE_ESTABLISHED:
2084 spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
2089 int tcp_seq_open(struct inode *inode, struct file *file)
2091 struct tcp_seq_afinfo *afinfo = PDE_DATA(inode);
2092 struct tcp_iter_state *s;
2095 err = seq_open_net(inode, file, &afinfo->seq_ops,
2096 sizeof(struct tcp_iter_state));
2100 s = ((struct seq_file *)file->private_data)->private;
2101 s->family = afinfo->family;
2105 EXPORT_SYMBOL(tcp_seq_open);
2107 int tcp_proc_register(struct net *net, struct tcp_seq_afinfo *afinfo)
2110 struct proc_dir_entry *p;
2112 afinfo->seq_ops.start = tcp_seq_start;
2113 afinfo->seq_ops.next = tcp_seq_next;
2114 afinfo->seq_ops.stop = tcp_seq_stop;
2116 p = proc_create_data(afinfo->name, S_IRUGO, net->proc_net,
2117 afinfo->seq_fops, afinfo);
2122 EXPORT_SYMBOL(tcp_proc_register);
2124 void tcp_proc_unregister(struct net *net, struct tcp_seq_afinfo *afinfo)
2126 remove_proc_entry(afinfo->name, net->proc_net);
2128 EXPORT_SYMBOL(tcp_proc_unregister);
2130 static void get_openreq4(const struct request_sock *req,
2131 struct seq_file *f, int i)
2133 const struct inet_request_sock *ireq = inet_rsk(req);
2134 long delta = req->rsk_timer.expires - jiffies;
2136 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2137 " %02X %08X:%08X %02X:%08lX %08X %5u %8d %u %d %pK",
2142 ntohs(ireq->ir_rmt_port),
2144 0, 0, /* could print option size, but that is af dependent. */
2145 1, /* timers active (only the expire timer) */
2146 jiffies_delta_to_clock_t(delta),
2148 from_kuid_munged(seq_user_ns(f),
2149 sock_i_uid(req->rsk_listener)),
2150 0, /* non standard timer */
2151 0, /* open_requests have no inode */
2156 static void get_tcp4_sock(struct sock *sk, struct seq_file *f, int i)
2159 unsigned long timer_expires;
2160 const struct tcp_sock *tp = tcp_sk(sk);
2161 const struct inet_connection_sock *icsk = inet_csk(sk);
2162 const struct inet_sock *inet = inet_sk(sk);
2163 const struct fastopen_queue *fastopenq = &icsk->icsk_accept_queue.fastopenq;
2164 __be32 dest = inet->inet_daddr;
2165 __be32 src = inet->inet_rcv_saddr;
2166 __u16 destp = ntohs(inet->inet_dport);
2167 __u16 srcp = ntohs(inet->inet_sport);
2171 if (icsk->icsk_pending == ICSK_TIME_RETRANS ||
2172 icsk->icsk_pending == ICSK_TIME_EARLY_RETRANS ||
2173 icsk->icsk_pending == ICSK_TIME_LOSS_PROBE) {
2175 timer_expires = icsk->icsk_timeout;
2176 } else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
2178 timer_expires = icsk->icsk_timeout;
2179 } else if (timer_pending(&sk->sk_timer)) {
2181 timer_expires = sk->sk_timer.expires;
2184 timer_expires = jiffies;
2187 state = sk_state_load(sk);
2188 if (state == TCP_LISTEN)
2189 rx_queue = sk->sk_ack_backlog;
2191 /* Because we don't lock the socket,
2192 * we might find a transient negative value.
2194 rx_queue = max_t(int, tp->rcv_nxt - tp->copied_seq, 0);
2196 seq_printf(f, "%4d: %08X:%04X %08X:%04X %02X %08X:%08X %02X:%08lX "
2197 "%08X %5u %8d %lu %d %pK %lu %lu %u %u %d",
2198 i, src, srcp, dest, destp, state,
2199 tp->write_seq - tp->snd_una,
2202 jiffies_delta_to_clock_t(timer_expires - jiffies),
2203 icsk->icsk_retransmits,
2204 from_kuid_munged(seq_user_ns(f), sock_i_uid(sk)),
2205 icsk->icsk_probes_out,
2207 atomic_read(&sk->sk_refcnt), sk,
2208 jiffies_to_clock_t(icsk->icsk_rto),
2209 jiffies_to_clock_t(icsk->icsk_ack.ato),
2210 (icsk->icsk_ack.quick << 1) | icsk->icsk_ack.pingpong,
2212 state == TCP_LISTEN ?
2213 fastopenq->max_qlen :
2214 (tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh));
2217 static void get_timewait4_sock(const struct inet_timewait_sock *tw,
2218 struct seq_file *f, int i)
2220 long delta = tw->tw_timer.expires - jiffies;
2224 dest = tw->tw_daddr;
2225 src = tw->tw_rcv_saddr;
2226 destp = ntohs(tw->tw_dport);
2227 srcp = ntohs(tw->tw_sport);
2229 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2230 " %02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK",
2231 i, src, srcp, dest, destp, tw->tw_substate, 0, 0,
2232 3, jiffies_delta_to_clock_t(delta), 0, 0, 0, 0,
2233 atomic_read(&tw->tw_refcnt), tw);
2238 static int tcp4_seq_show(struct seq_file *seq, void *v)
2240 struct tcp_iter_state *st;
2241 struct sock *sk = v;
2243 seq_setwidth(seq, TMPSZ - 1);
2244 if (v == SEQ_START_TOKEN) {
2245 seq_puts(seq, " sl local_address rem_address st tx_queue "
2246 "rx_queue tr tm->when retrnsmt uid timeout "
2252 if (sk->sk_state == TCP_TIME_WAIT)
2253 get_timewait4_sock(v, seq, st->num);
2254 else if (sk->sk_state == TCP_NEW_SYN_RECV)
2255 get_openreq4(v, seq, st->num);
2257 get_tcp4_sock(v, seq, st->num);
2263 static const struct file_operations tcp_afinfo_seq_fops = {
2264 .owner = THIS_MODULE,
2265 .open = tcp_seq_open,
2267 .llseek = seq_lseek,
2268 .release = seq_release_net
2271 static struct tcp_seq_afinfo tcp4_seq_afinfo = {
2274 .seq_fops = &tcp_afinfo_seq_fops,
2276 .show = tcp4_seq_show,
2280 static int __net_init tcp4_proc_init_net(struct net *net)
2282 return tcp_proc_register(net, &tcp4_seq_afinfo);
2285 static void __net_exit tcp4_proc_exit_net(struct net *net)
2287 tcp_proc_unregister(net, &tcp4_seq_afinfo);
2290 static struct pernet_operations tcp4_net_ops = {
2291 .init = tcp4_proc_init_net,
2292 .exit = tcp4_proc_exit_net,
2295 int __init tcp4_proc_init(void)
2297 return register_pernet_subsys(&tcp4_net_ops);
2300 void tcp4_proc_exit(void)
2302 unregister_pernet_subsys(&tcp4_net_ops);
2304 #endif /* CONFIG_PROC_FS */
2306 struct proto tcp_prot = {
2308 .owner = THIS_MODULE,
2310 .connect = tcp_v4_connect,
2311 .disconnect = tcp_disconnect,
2312 .accept = inet_csk_accept,
2314 .init = tcp_v4_init_sock,
2315 .destroy = tcp_v4_destroy_sock,
2316 .shutdown = tcp_shutdown,
2317 .setsockopt = tcp_setsockopt,
2318 .getsockopt = tcp_getsockopt,
2319 .recvmsg = tcp_recvmsg,
2320 .sendmsg = tcp_sendmsg,
2321 .sendpage = tcp_sendpage,
2322 .backlog_rcv = tcp_v4_do_rcv,
2323 .release_cb = tcp_release_cb,
2325 .unhash = inet_unhash,
2326 .get_port = inet_csk_get_port,
2327 .enter_memory_pressure = tcp_enter_memory_pressure,
2328 .stream_memory_free = tcp_stream_memory_free,
2329 .sockets_allocated = &tcp_sockets_allocated,
2330 .orphan_count = &tcp_orphan_count,
2331 .memory_allocated = &tcp_memory_allocated,
2332 .memory_pressure = &tcp_memory_pressure,
2333 .sysctl_mem = sysctl_tcp_mem,
2334 .sysctl_wmem = sysctl_tcp_wmem,
2335 .sysctl_rmem = sysctl_tcp_rmem,
2336 .max_header = MAX_TCP_HEADER,
2337 .obj_size = sizeof(struct tcp_sock),
2338 .slab_flags = SLAB_DESTROY_BY_RCU,
2339 .twsk_prot = &tcp_timewait_sock_ops,
2340 .rsk_prot = &tcp_request_sock_ops,
2341 .h.hashinfo = &tcp_hashinfo,
2342 .no_autobind = true,
2343 #ifdef CONFIG_COMPAT
2344 .compat_setsockopt = compat_tcp_setsockopt,
2345 .compat_getsockopt = compat_tcp_getsockopt,
2347 #ifdef CONFIG_MEMCG_KMEM
2348 .init_cgroup = tcp_init_cgroup,
2349 .destroy_cgroup = tcp_destroy_cgroup,
2350 .proto_cgroup = tcp_proto_cgroup,
2352 .diag_destroy = tcp_abort,
2354 EXPORT_SYMBOL(tcp_prot);
2356 static void __net_exit tcp_sk_exit(struct net *net)
2360 for_each_possible_cpu(cpu)
2361 inet_ctl_sock_destroy(*per_cpu_ptr(net->ipv4.tcp_sk, cpu));
2362 free_percpu(net->ipv4.tcp_sk);
2365 static int __net_init tcp_sk_init(struct net *net)
2369 net->ipv4.tcp_sk = alloc_percpu(struct sock *);
2370 if (!net->ipv4.tcp_sk)
2373 for_each_possible_cpu(cpu) {
2376 res = inet_ctl_sock_create(&sk, PF_INET, SOCK_RAW,
2380 *per_cpu_ptr(net->ipv4.tcp_sk, cpu) = sk;
2383 net->ipv4.sysctl_tcp_ecn = 2;
2384 net->ipv4.sysctl_tcp_ecn_fallback = 1;
2386 net->ipv4.sysctl_tcp_base_mss = TCP_BASE_MSS;
2387 net->ipv4.sysctl_tcp_probe_threshold = TCP_PROBE_THRESHOLD;
2388 net->ipv4.sysctl_tcp_probe_interval = TCP_PROBE_INTERVAL;
2397 static void __net_exit tcp_sk_exit_batch(struct list_head *net_exit_list)
2399 inet_twsk_purge(&tcp_hashinfo, &tcp_death_row, AF_INET);
2402 static struct pernet_operations __net_initdata tcp_sk_ops = {
2403 .init = tcp_sk_init,
2404 .exit = tcp_sk_exit,
2405 .exit_batch = tcp_sk_exit_batch,
2408 void __init tcp_v4_init(void)
2410 inet_hashinfo_init(&tcp_hashinfo);
2411 if (register_pernet_subsys(&tcp_sk_ops))
2412 panic("Failed to create the TCP control socket.\n");