2 * INET An implementation of the TCP/IP protocol suite for the LINUX
3 * operating system. INET is implemented using the BSD Socket
4 * interface as the means of communication with the user level.
6 * Implementation of the Transmission Control Protocol(TCP).
8 * IPv4 specific functions
13 * linux/ipv4/tcp_input.c
14 * linux/ipv4/tcp_output.c
16 * See tcp.c for author information
18 * This program is free software; you can redistribute it and/or
19 * modify it under the terms of the GNU General Public License
20 * as published by the Free Software Foundation; either version
21 * 2 of the License, or (at your option) any later version.
26 * David S. Miller : New socket lookup architecture.
27 * This code is dedicated to John Dyson.
28 * David S. Miller : Change semantics of established hash,
29 * half is devoted to TIME_WAIT sockets
30 * and the rest go in the other half.
31 * Andi Kleen : Add support for syncookies and fixed
32 * some bugs: ip options weren't passed to
33 * the TCP layer, missed a check for an
35 * Andi Kleen : Implemented fast path mtu discovery.
36 * Fixed many serious bugs in the
37 * request_sock handling and moved
38 * most of it into the af independent code.
39 * Added tail drop and some other bugfixes.
40 * Added new listen semantics.
41 * Mike McLagan : Routing by source
42 * Juan Jose Ciarlante: ip_dynaddr bits
43 * Andi Kleen: various fixes.
44 * Vitaly E. Lavrov : Transparent proxy revived after year
46 * Andi Kleen : Fix new listen.
47 * Andi Kleen : Fix accept error reporting.
48 * YOSHIFUJI Hideaki @USAGI and: Support IPV6_V6ONLY socket option, which
49 * Alexey Kuznetsov allow both IPv4 and IPv6 sockets to bind
50 * a single port at the same time.
53 #define pr_fmt(fmt) "TCP: " fmt
55 #include <linux/bottom_half.h>
56 #include <linux/types.h>
57 #include <linux/fcntl.h>
58 #include <linux/module.h>
59 #include <linux/random.h>
60 #include <linux/cache.h>
61 #include <linux/jhash.h>
62 #include <linux/init.h>
63 #include <linux/times.h>
64 #include <linux/slab.h>
66 #include <net/net_namespace.h>
68 #include <net/inet_hashtables.h>
70 #include <net/transp_v6.h>
72 #include <net/inet_common.h>
73 #include <net/timewait_sock.h>
75 #include <net/secure_seq.h>
76 #include <net/tcp_memcontrol.h>
77 #include <net/busy_poll.h>
79 #include <linux/inet.h>
80 #include <linux/ipv6.h>
81 #include <linux/stddef.h>
82 #include <linux/proc_fs.h>
83 #include <linux/seq_file.h>
85 #include <linux/crypto.h>
86 #include <linux/scatterlist.h>
88 int sysctl_tcp_tw_reuse __read_mostly;
89 int sysctl_tcp_low_latency __read_mostly;
90 EXPORT_SYMBOL(sysctl_tcp_low_latency);
92 #ifdef CONFIG_TCP_MD5SIG
93 static int tcp_v4_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key,
94 __be32 daddr, __be32 saddr, const struct tcphdr *th);
97 struct inet_hashinfo tcp_hashinfo;
98 EXPORT_SYMBOL(tcp_hashinfo);
100 static __u32 tcp_v4_init_sequence(const struct sk_buff *skb)
102 return secure_tcp_sequence_number(ip_hdr(skb)->daddr,
105 tcp_hdr(skb)->source);
108 int tcp_twsk_unique(struct sock *sk, struct sock *sktw, void *twp)
110 const struct tcp_timewait_sock *tcptw = tcp_twsk(sktw);
111 struct tcp_sock *tp = tcp_sk(sk);
113 /* With PAWS, it is safe from the viewpoint
114 of data integrity. Even without PAWS it is safe provided sequence
115 spaces do not overlap i.e. at data rates <= 80Mbit/sec.
117 Actually, the idea is close to VJ's one, only timestamp cache is
118 held not per host, but per port pair and TW bucket is used as state
121 If TW bucket has been already destroyed we fall back to VJ's scheme
122 and use initial timestamp retrieved from peer table.
124 if (tcptw->tw_ts_recent_stamp &&
125 (!twp || (sysctl_tcp_tw_reuse &&
126 get_seconds() - tcptw->tw_ts_recent_stamp > 1))) {
127 tp->write_seq = tcptw->tw_snd_nxt + 65535 + 2;
128 if (tp->write_seq == 0)
130 tp->rx_opt.ts_recent = tcptw->tw_ts_recent;
131 tp->rx_opt.ts_recent_stamp = tcptw->tw_ts_recent_stamp;
138 EXPORT_SYMBOL_GPL(tcp_twsk_unique);
140 /* This will initiate an outgoing connection. */
141 int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
143 struct sockaddr_in *usin = (struct sockaddr_in *)uaddr;
144 struct inet_sock *inet = inet_sk(sk);
145 struct tcp_sock *tp = tcp_sk(sk);
146 __be16 orig_sport, orig_dport;
147 __be32 daddr, nexthop;
151 struct ip_options_rcu *inet_opt;
153 if (addr_len < sizeof(struct sockaddr_in))
156 if (usin->sin_family != AF_INET)
157 return -EAFNOSUPPORT;
159 nexthop = daddr = usin->sin_addr.s_addr;
160 inet_opt = rcu_dereference_protected(inet->inet_opt,
161 sock_owned_by_user(sk));
162 if (inet_opt && inet_opt->opt.srr) {
165 nexthop = inet_opt->opt.faddr;
168 orig_sport = inet->inet_sport;
169 orig_dport = usin->sin_port;
170 fl4 = &inet->cork.fl.u.ip4;
171 rt = ip_route_connect(fl4, nexthop, inet->inet_saddr,
172 RT_CONN_FLAGS(sk), sk->sk_bound_dev_if,
174 orig_sport, orig_dport, sk);
177 if (err == -ENETUNREACH)
178 IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTNOROUTES);
182 if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) {
187 if (!inet_opt || !inet_opt->opt.srr)
190 if (!inet->inet_saddr)
191 inet->inet_saddr = fl4->saddr;
192 sk_rcv_saddr_set(sk, inet->inet_saddr);
194 if (tp->rx_opt.ts_recent_stamp && inet->inet_daddr != daddr) {
195 /* Reset inherited state */
196 tp->rx_opt.ts_recent = 0;
197 tp->rx_opt.ts_recent_stamp = 0;
198 if (likely(!tp->repair))
202 if (tcp_death_row.sysctl_tw_recycle &&
203 !tp->rx_opt.ts_recent_stamp && fl4->daddr == daddr)
204 tcp_fetch_timewait_stamp(sk, &rt->dst);
206 inet->inet_dport = usin->sin_port;
207 sk_daddr_set(sk, daddr);
209 inet_csk(sk)->icsk_ext_hdr_len = 0;
211 inet_csk(sk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
213 tp->rx_opt.mss_clamp = TCP_MSS_DEFAULT;
215 /* Socket identity is still unknown (sport may be zero).
216 * However we set state to SYN-SENT and not releasing socket
217 * lock select source port, enter ourselves into the hash tables and
218 * complete initialization after this.
220 tcp_set_state(sk, TCP_SYN_SENT);
221 err = inet_hash_connect(&tcp_death_row, sk);
227 rt = ip_route_newports(fl4, rt, orig_sport, orig_dport,
228 inet->inet_sport, inet->inet_dport, sk);
234 /* OK, now commit destination to socket. */
235 sk->sk_gso_type = SKB_GSO_TCPV4;
236 sk_setup_caps(sk, &rt->dst);
238 if (!tp->write_seq && likely(!tp->repair))
239 tp->write_seq = secure_tcp_sequence_number(inet->inet_saddr,
244 inet->inet_id = tp->write_seq ^ jiffies;
246 err = tcp_connect(sk);
256 * This unhashes the socket and releases the local port,
259 tcp_set_state(sk, TCP_CLOSE);
261 sk->sk_route_caps = 0;
262 inet->inet_dport = 0;
265 EXPORT_SYMBOL(tcp_v4_connect);
268 * This routine reacts to ICMP_FRAG_NEEDED mtu indications as defined in RFC1191.
269 * It can be called through tcp_release_cb() if socket was owned by user
270 * at the time tcp_v4_err() was called to handle ICMP message.
272 void tcp_v4_mtu_reduced(struct sock *sk)
274 struct dst_entry *dst;
275 struct inet_sock *inet = inet_sk(sk);
276 u32 mtu = tcp_sk(sk)->mtu_info;
278 dst = inet_csk_update_pmtu(sk, mtu);
282 /* Something is about to be wrong... Remember soft error
283 * for the case, if this connection will not able to recover.
285 if (mtu < dst_mtu(dst) && ip_dont_fragment(sk, dst))
286 sk->sk_err_soft = EMSGSIZE;
290 if (inet->pmtudisc != IP_PMTUDISC_DONT &&
291 ip_sk_accept_pmtu(sk) &&
292 inet_csk(sk)->icsk_pmtu_cookie > mtu) {
293 tcp_sync_mss(sk, mtu);
295 /* Resend the TCP packet because it's
296 * clear that the old packet has been
297 * dropped. This is the new "fast" path mtu
300 tcp_simple_retransmit(sk);
301 } /* else let the usual retransmit timer handle it */
303 EXPORT_SYMBOL(tcp_v4_mtu_reduced);
305 static void do_redirect(struct sk_buff *skb, struct sock *sk)
307 struct dst_entry *dst = __sk_dst_check(sk, 0);
310 dst->ops->redirect(dst, sk, skb);
314 /* handle ICMP messages on TCP_NEW_SYN_RECV request sockets */
315 void tcp_req_err(struct sock *sk, u32 seq)
317 struct request_sock *req = inet_reqsk(sk);
318 struct net *net = sock_net(sk);
320 /* ICMPs are not backlogged, hence we cannot get
321 * an established socket here.
325 if (seq != tcp_rsk(req)->snt_isn) {
326 NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
330 * Still in SYN_RECV, just remove it silently.
331 * There is no good way to pass the error to the newly
332 * created socket, and POSIX does not want network
333 * errors returned from accept().
335 NET_INC_STATS_BH(net, LINUX_MIB_LISTENDROPS);
336 inet_csk_reqsk_queue_drop(req->rsk_listener, req);
339 EXPORT_SYMBOL(tcp_req_err);
342 * This routine is called by the ICMP module when it gets some
343 * sort of error condition. If err < 0 then the socket should
344 * be closed and the error returned to the user. If err > 0
345 * it's just the icmp type << 8 | icmp code. After adjustment
346 * header points to the first 8 bytes of the tcp header. We need
347 * to find the appropriate port.
349 * The locking strategy used here is very "optimistic". When
350 * someone else accesses the socket the ICMP is just dropped
351 * and for some paths there is no check at all.
352 * A more general error queue to queue errors for later handling
353 * is probably better.
357 void tcp_v4_err(struct sk_buff *icmp_skb, u32 info)
359 const struct iphdr *iph = (const struct iphdr *)icmp_skb->data;
360 struct tcphdr *th = (struct tcphdr *)(icmp_skb->data + (iph->ihl << 2));
361 struct inet_connection_sock *icsk;
363 struct inet_sock *inet;
364 const int type = icmp_hdr(icmp_skb)->type;
365 const int code = icmp_hdr(icmp_skb)->code;
368 struct request_sock *fastopen;
372 struct net *net = dev_net(icmp_skb->dev);
374 sk = __inet_lookup_established(net, &tcp_hashinfo, iph->daddr,
375 th->dest, iph->saddr, ntohs(th->source),
378 ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS);
381 if (sk->sk_state == TCP_TIME_WAIT) {
382 inet_twsk_put(inet_twsk(sk));
385 seq = ntohl(th->seq);
386 if (sk->sk_state == TCP_NEW_SYN_RECV)
387 return tcp_req_err(sk, seq);
390 /* If too many ICMPs get dropped on busy
391 * servers this needs to be solved differently.
392 * We do take care of PMTU discovery (RFC1191) special case :
393 * we can receive locally generated ICMP messages while socket is held.
395 if (sock_owned_by_user(sk)) {
396 if (!(type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED))
397 NET_INC_STATS_BH(net, LINUX_MIB_LOCKDROPPEDICMPS);
399 if (sk->sk_state == TCP_CLOSE)
402 if (unlikely(iph->ttl < inet_sk(sk)->min_ttl)) {
403 NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP);
409 /* XXX (TFO) - tp->snd_una should be ISN (tcp_create_openreq_child() */
410 fastopen = tp->fastopen_rsk;
411 snd_una = fastopen ? tcp_rsk(fastopen)->snt_isn : tp->snd_una;
412 if (sk->sk_state != TCP_LISTEN &&
413 !between(seq, snd_una, tp->snd_nxt)) {
414 NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
420 do_redirect(icmp_skb, sk);
422 case ICMP_SOURCE_QUENCH:
423 /* Just silently ignore these. */
425 case ICMP_PARAMETERPROB:
428 case ICMP_DEST_UNREACH:
429 if (code > NR_ICMP_UNREACH)
432 if (code == ICMP_FRAG_NEEDED) { /* PMTU discovery (RFC1191) */
433 /* We are not interested in TCP_LISTEN and open_requests
434 * (SYN-ACKs send out by Linux are always <576bytes so
435 * they should go through unfragmented).
437 if (sk->sk_state == TCP_LISTEN)
441 if (!sock_owned_by_user(sk)) {
442 tcp_v4_mtu_reduced(sk);
444 if (!test_and_set_bit(TCP_MTU_REDUCED_DEFERRED, &tp->tsq_flags))
450 err = icmp_err_convert[code].errno;
451 /* check if icmp_skb allows revert of backoff
452 * (see draft-zimmermann-tcp-lcd) */
453 if (code != ICMP_NET_UNREACH && code != ICMP_HOST_UNREACH)
455 if (seq != tp->snd_una || !icsk->icsk_retransmits ||
456 !icsk->icsk_backoff || fastopen)
459 if (sock_owned_by_user(sk))
462 icsk->icsk_backoff--;
463 icsk->icsk_rto = tp->srtt_us ? __tcp_set_rto(tp) :
465 icsk->icsk_rto = inet_csk_rto_backoff(icsk, TCP_RTO_MAX);
467 skb = tcp_write_queue_head(sk);
470 remaining = icsk->icsk_rto -
472 tcp_time_stamp - tcp_skb_timestamp(skb));
475 inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
476 remaining, TCP_RTO_MAX);
478 /* RTO revert clocked out retransmission.
479 * Will retransmit now */
480 tcp_retransmit_timer(sk);
484 case ICMP_TIME_EXCEEDED:
491 switch (sk->sk_state) {
494 /* Only in fast or simultaneous open. If a fast open socket is
495 * is already accepted it is treated as a connected one below.
497 if (fastopen && !fastopen->sk)
500 if (!sock_owned_by_user(sk)) {
503 sk->sk_error_report(sk);
507 sk->sk_err_soft = err;
512 /* If we've already connected we will keep trying
513 * until we time out, or the user gives up.
515 * rfc1122 4.2.3.9 allows to consider as hard errors
516 * only PROTO_UNREACH and PORT_UNREACH (well, FRAG_FAILED too,
517 * but it is obsoleted by pmtu discovery).
519 * Note, that in modern internet, where routing is unreliable
520 * and in each dark corner broken firewalls sit, sending random
521 * errors ordered by their masters even this two messages finally lose
522 * their original sense (even Linux sends invalid PORT_UNREACHs)
524 * Now we are in compliance with RFCs.
529 if (!sock_owned_by_user(sk) && inet->recverr) {
531 sk->sk_error_report(sk);
532 } else { /* Only an error on timeout */
533 sk->sk_err_soft = err;
541 void __tcp_v4_send_check(struct sk_buff *skb, __be32 saddr, __be32 daddr)
543 struct tcphdr *th = tcp_hdr(skb);
545 if (skb->ip_summed == CHECKSUM_PARTIAL) {
546 th->check = ~tcp_v4_check(skb->len, saddr, daddr, 0);
547 skb->csum_start = skb_transport_header(skb) - skb->head;
548 skb->csum_offset = offsetof(struct tcphdr, check);
550 th->check = tcp_v4_check(skb->len, saddr, daddr,
557 /* This routine computes an IPv4 TCP checksum. */
558 void tcp_v4_send_check(struct sock *sk, struct sk_buff *skb)
560 const struct inet_sock *inet = inet_sk(sk);
562 __tcp_v4_send_check(skb, inet->inet_saddr, inet->inet_daddr);
564 EXPORT_SYMBOL(tcp_v4_send_check);
567 * This routine will send an RST to the other tcp.
569 * Someone asks: why I NEVER use socket parameters (TOS, TTL etc.)
571 * Answer: if a packet caused RST, it is not for a socket
572 * existing in our system, if it is matched to a socket,
573 * it is just duplicate segment or bug in other side's TCP.
574 * So that we build reply only basing on parameters
575 * arrived with segment.
576 * Exception: precedence violation. We do not implement it in any case.
579 static void tcp_v4_send_reset(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(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->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(struct sock *sk, struct dst_entry *dst,
823 struct request_sock *req,
825 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);
839 __tcp_v4_send_check(skb, ireq->ir_loc_addr, ireq->ir_rmt_addr);
841 skb_set_queue_mapping(skb, queue_mapping);
842 err = ip_build_and_send_pkt(skb, sk, ireq->ir_loc_addr,
845 err = net_xmit_eval(err);
852 * IPv4 request_sock destructor.
854 static void tcp_v4_reqsk_destructor(struct request_sock *req)
856 kfree(inet_rsk(req)->opt);
860 #ifdef CONFIG_TCP_MD5SIG
862 * RFC2385 MD5 checksumming requires a mapping of
863 * IP address->MD5 Key.
864 * We need to maintain these in the sk structure.
867 /* Find the Key structure for an address. */
868 struct tcp_md5sig_key *tcp_md5_do_lookup(struct sock *sk,
869 const union tcp_md5_addr *addr,
872 const struct tcp_sock *tp = tcp_sk(sk);
873 struct tcp_md5sig_key *key;
874 unsigned int size = sizeof(struct in_addr);
875 const struct tcp_md5sig_info *md5sig;
877 /* caller either holds rcu_read_lock() or socket lock */
878 md5sig = rcu_dereference_check(tp->md5sig_info,
879 sock_owned_by_user(sk) ||
880 lockdep_is_held(&sk->sk_lock.slock));
883 #if IS_ENABLED(CONFIG_IPV6)
884 if (family == AF_INET6)
885 size = sizeof(struct in6_addr);
887 hlist_for_each_entry_rcu(key, &md5sig->head, node) {
888 if (key->family != family)
890 if (!memcmp(&key->addr, addr, size))
895 EXPORT_SYMBOL(tcp_md5_do_lookup);
897 struct tcp_md5sig_key *tcp_v4_md5_lookup(struct sock *sk,
898 const struct sock *addr_sk)
900 const union tcp_md5_addr *addr;
902 addr = (const union tcp_md5_addr *)&addr_sk->sk_daddr;
903 return tcp_md5_do_lookup(sk, addr, AF_INET);
905 EXPORT_SYMBOL(tcp_v4_md5_lookup);
907 /* This can be called on a newly created socket, from other files */
908 int tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr,
909 int family, const u8 *newkey, u8 newkeylen, gfp_t gfp)
911 /* Add Key to the list */
912 struct tcp_md5sig_key *key;
913 struct tcp_sock *tp = tcp_sk(sk);
914 struct tcp_md5sig_info *md5sig;
916 key = tcp_md5_do_lookup(sk, addr, family);
918 /* Pre-existing entry - just update that one. */
919 memcpy(key->key, newkey, newkeylen);
920 key->keylen = newkeylen;
924 md5sig = rcu_dereference_protected(tp->md5sig_info,
925 sock_owned_by_user(sk));
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);
1115 /* Called with rcu_read_lock() */
1116 static bool tcp_v4_inbound_md5_hash(struct sock *sk,
1117 const struct sk_buff *skb)
1120 * This gets called for each TCP segment that arrives
1121 * so we want to be efficient.
1122 * We have 3 drop cases:
1123 * o No MD5 hash and one expected.
1124 * o MD5 hash and we're not expecting one.
1125 * o MD5 hash and its wrong.
1127 const __u8 *hash_location = NULL;
1128 struct tcp_md5sig_key *hash_expected;
1129 const struct iphdr *iph = ip_hdr(skb);
1130 const struct tcphdr *th = tcp_hdr(skb);
1132 unsigned char newhash[16];
1134 hash_expected = tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&iph->saddr,
1136 hash_location = tcp_parse_md5sig_option(th);
1138 /* We've parsed the options - do we have a hash? */
1139 if (!hash_expected && !hash_location)
1142 if (hash_expected && !hash_location) {
1143 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5NOTFOUND);
1147 if (!hash_expected && hash_location) {
1148 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5UNEXPECTED);
1152 /* Okay, so this is hash_expected and hash_location -
1153 * so we need to calculate the checksum.
1155 genhash = tcp_v4_md5_hash_skb(newhash,
1159 if (genhash || memcmp(hash_location, newhash, 16) != 0) {
1160 net_info_ratelimited("MD5 Hash failed for (%pI4, %d)->(%pI4, %d)%s\n",
1161 &iph->saddr, ntohs(th->source),
1162 &iph->daddr, ntohs(th->dest),
1163 genhash ? " tcp_v4_calc_md5_hash failed"
1171 static void tcp_v4_init_req(struct request_sock *req, struct sock *sk_listener,
1172 struct sk_buff *skb)
1174 struct inet_request_sock *ireq = inet_rsk(req);
1176 sk_rcv_saddr_set(req_to_sk(req), ip_hdr(skb)->daddr);
1177 sk_daddr_set(req_to_sk(req), ip_hdr(skb)->saddr);
1178 ireq->no_srccheck = inet_sk(sk_listener)->transparent;
1179 ireq->opt = tcp_v4_save_options(skb);
1182 static struct dst_entry *tcp_v4_route_req(struct sock *sk, struct flowi *fl,
1183 const struct request_sock *req,
1186 struct dst_entry *dst = inet_csk_route_req(sk, &fl->u.ip4, req);
1189 if (fl->u.ip4.daddr == inet_rsk(req)->ir_rmt_addr)
1198 struct request_sock_ops tcp_request_sock_ops __read_mostly = {
1200 .obj_size = sizeof(struct tcp_request_sock),
1201 .rtx_syn_ack = tcp_rtx_synack,
1202 .send_ack = tcp_v4_reqsk_send_ack,
1203 .destructor = tcp_v4_reqsk_destructor,
1204 .send_reset = tcp_v4_send_reset,
1205 .syn_ack_timeout = tcp_syn_ack_timeout,
1208 static const struct tcp_request_sock_ops tcp_request_sock_ipv4_ops = {
1209 .mss_clamp = TCP_MSS_DEFAULT,
1210 #ifdef CONFIG_TCP_MD5SIG
1211 .req_md5_lookup = tcp_v4_md5_lookup,
1212 .calc_md5_hash = tcp_v4_md5_hash_skb,
1214 .init_req = tcp_v4_init_req,
1215 #ifdef CONFIG_SYN_COOKIES
1216 .cookie_init_seq = cookie_v4_init_sequence,
1218 .route_req = tcp_v4_route_req,
1219 .init_seq = tcp_v4_init_sequence,
1220 .send_synack = tcp_v4_send_synack,
1221 .queue_hash_add = inet_csk_reqsk_queue_hash_add,
1224 int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
1226 /* Never answer to SYNs send to broadcast or multicast */
1227 if (skb_rtable(skb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
1230 return tcp_conn_request(&tcp_request_sock_ops,
1231 &tcp_request_sock_ipv4_ops, sk, skb);
1234 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
1237 EXPORT_SYMBOL(tcp_v4_conn_request);
1241 * The three way handshake has completed - we got a valid synack -
1242 * now create the new socket.
1244 struct sock *tcp_v4_syn_recv_sock(struct sock *sk, struct sk_buff *skb,
1245 struct request_sock *req,
1246 struct dst_entry *dst)
1248 struct inet_request_sock *ireq;
1249 struct inet_sock *newinet;
1250 struct tcp_sock *newtp;
1252 #ifdef CONFIG_TCP_MD5SIG
1253 struct tcp_md5sig_key *key;
1255 struct ip_options_rcu *inet_opt;
1257 if (sk_acceptq_is_full(sk))
1260 newsk = tcp_create_openreq_child(sk, req, skb);
1264 newsk->sk_gso_type = SKB_GSO_TCPV4;
1265 inet_sk_rx_dst_set(newsk, skb);
1267 newtp = tcp_sk(newsk);
1268 newinet = inet_sk(newsk);
1269 ireq = inet_rsk(req);
1270 sk_daddr_set(newsk, ireq->ir_rmt_addr);
1271 sk_rcv_saddr_set(newsk, ireq->ir_loc_addr);
1272 newinet->inet_saddr = ireq->ir_loc_addr;
1273 inet_opt = ireq->opt;
1274 rcu_assign_pointer(newinet->inet_opt, inet_opt);
1276 newinet->mc_index = inet_iif(skb);
1277 newinet->mc_ttl = ip_hdr(skb)->ttl;
1278 newinet->rcv_tos = ip_hdr(skb)->tos;
1279 inet_csk(newsk)->icsk_ext_hdr_len = 0;
1280 sk_set_txhash(newsk);
1282 inet_csk(newsk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
1283 newinet->inet_id = newtp->write_seq ^ jiffies;
1286 dst = inet_csk_route_child_sock(sk, newsk, req);
1290 /* syncookie case : see end of cookie_v4_check() */
1292 sk_setup_caps(newsk, dst);
1294 tcp_ca_openreq_child(newsk, dst);
1296 tcp_sync_mss(newsk, dst_mtu(dst));
1297 newtp->advmss = dst_metric_advmss(dst);
1298 if (tcp_sk(sk)->rx_opt.user_mss &&
1299 tcp_sk(sk)->rx_opt.user_mss < newtp->advmss)
1300 newtp->advmss = tcp_sk(sk)->rx_opt.user_mss;
1302 tcp_initialize_rcv_mss(newsk);
1304 #ifdef CONFIG_TCP_MD5SIG
1305 /* Copy over the MD5 key from the original socket */
1306 key = tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&newinet->inet_daddr,
1310 * We're using one, so create a matching key
1311 * on the newsk structure. If we fail to get
1312 * memory, then we end up not copying the key
1315 tcp_md5_do_add(newsk, (union tcp_md5_addr *)&newinet->inet_daddr,
1316 AF_INET, key->key, key->keylen, GFP_ATOMIC);
1317 sk_nocaps_add(newsk, NETIF_F_GSO_MASK);
1321 if (__inet_inherit_port(sk, newsk) < 0)
1323 __inet_hash_nolisten(newsk, NULL);
1328 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
1332 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
1335 inet_csk_prepare_forced_close(newsk);
1339 EXPORT_SYMBOL(tcp_v4_syn_recv_sock);
1341 static struct sock *tcp_v4_hnd_req(struct sock *sk, struct sk_buff *skb)
1343 const struct tcphdr *th = tcp_hdr(skb);
1344 const struct iphdr *iph = ip_hdr(skb);
1345 struct request_sock *req;
1348 req = inet_csk_search_req(sk, th->source, iph->saddr, iph->daddr);
1350 nsk = tcp_check_req(sk, skb, req, false);
1351 if (!nsk || nsk == sk)
1356 nsk = inet_lookup_established(sock_net(sk), &tcp_hashinfo, iph->saddr,
1357 th->source, iph->daddr, th->dest, inet_iif(skb));
1360 if (nsk->sk_state != TCP_TIME_WAIT) {
1364 inet_twsk_put(inet_twsk(nsk));
1368 #ifdef CONFIG_SYN_COOKIES
1370 sk = cookie_v4_check(sk, skb);
1375 /* The socket must have it's spinlock held when we get
1378 * We have a potential double-lock case here, so even when
1379 * doing backlog processing we use the BH locking scheme.
1380 * This is because we cannot sleep with the original spinlock
1383 int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
1387 if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
1388 struct dst_entry *dst = sk->sk_rx_dst;
1390 sock_rps_save_rxhash(sk, skb);
1391 sk_mark_napi_id(sk, skb);
1393 if (inet_sk(sk)->rx_dst_ifindex != skb->skb_iif ||
1394 !dst->ops->check(dst, 0)) {
1396 sk->sk_rx_dst = NULL;
1399 tcp_rcv_established(sk, skb, tcp_hdr(skb), skb->len);
1403 if (tcp_checksum_complete(skb))
1406 if (sk->sk_state == TCP_LISTEN) {
1407 struct sock *nsk = tcp_v4_hnd_req(sk, skb);
1412 sock_rps_save_rxhash(nsk, skb);
1413 sk_mark_napi_id(sk, skb);
1414 if (tcp_child_process(sk, nsk, skb)) {
1421 sock_rps_save_rxhash(sk, skb);
1423 if (tcp_rcv_state_process(sk, skb, tcp_hdr(skb), skb->len)) {
1430 tcp_v4_send_reset(rsk, skb);
1433 /* Be careful here. If this function gets more complicated and
1434 * gcc suffers from register pressure on the x86, sk (in %ebx)
1435 * might be destroyed here. This current version compiles correctly,
1436 * but you have been warned.
1441 TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_CSUMERRORS);
1442 TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_INERRS);
1445 EXPORT_SYMBOL(tcp_v4_do_rcv);
1447 void tcp_v4_early_demux(struct sk_buff *skb)
1449 const struct iphdr *iph;
1450 const struct tcphdr *th;
1453 if (skb->pkt_type != PACKET_HOST)
1456 if (!pskb_may_pull(skb, skb_transport_offset(skb) + sizeof(struct tcphdr)))
1462 if (th->doff < sizeof(struct tcphdr) / 4)
1465 sk = __inet_lookup_established(dev_net(skb->dev), &tcp_hashinfo,
1466 iph->saddr, th->source,
1467 iph->daddr, ntohs(th->dest),
1471 skb->destructor = sock_edemux;
1472 if (sk_fullsock(sk)) {
1473 struct dst_entry *dst = READ_ONCE(sk->sk_rx_dst);
1476 dst = dst_check(dst, 0);
1478 inet_sk(sk)->rx_dst_ifindex == skb->skb_iif)
1479 skb_dst_set_noref(skb, dst);
1484 /* Packet is added to VJ-style prequeue for processing in process
1485 * context, if a reader task is waiting. Apparently, this exciting
1486 * idea (VJ's mail "Re: query about TCP header on tcp-ip" of 07 Sep 93)
1487 * failed somewhere. Latency? Burstiness? Well, at least now we will
1488 * see, why it failed. 8)8) --ANK
1491 bool tcp_prequeue(struct sock *sk, struct sk_buff *skb)
1493 struct tcp_sock *tp = tcp_sk(sk);
1495 if (sysctl_tcp_low_latency || !tp->ucopy.task)
1498 if (skb->len <= tcp_hdrlen(skb) &&
1499 skb_queue_len(&tp->ucopy.prequeue) == 0)
1502 /* Before escaping RCU protected region, we need to take care of skb
1503 * dst. Prequeue is only enabled for established sockets.
1504 * For such sockets, we might need the skb dst only to set sk->sk_rx_dst
1505 * Instead of doing full sk_rx_dst validity here, let's perform
1506 * an optimistic check.
1508 if (likely(sk->sk_rx_dst))
1513 __skb_queue_tail(&tp->ucopy.prequeue, skb);
1514 tp->ucopy.memory += skb->truesize;
1515 if (tp->ucopy.memory > sk->sk_rcvbuf) {
1516 struct sk_buff *skb1;
1518 BUG_ON(sock_owned_by_user(sk));
1520 while ((skb1 = __skb_dequeue(&tp->ucopy.prequeue)) != NULL) {
1521 sk_backlog_rcv(sk, skb1);
1522 NET_INC_STATS_BH(sock_net(sk),
1523 LINUX_MIB_TCPPREQUEUEDROPPED);
1526 tp->ucopy.memory = 0;
1527 } else if (skb_queue_len(&tp->ucopy.prequeue) == 1) {
1528 wake_up_interruptible_sync_poll(sk_sleep(sk),
1529 POLLIN | POLLRDNORM | POLLRDBAND);
1530 if (!inet_csk_ack_scheduled(sk))
1531 inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK,
1532 (3 * tcp_rto_min(sk)) / 4,
1537 EXPORT_SYMBOL(tcp_prequeue);
1543 int tcp_v4_rcv(struct sk_buff *skb)
1545 const struct iphdr *iph;
1546 const struct tcphdr *th;
1549 struct net *net = dev_net(skb->dev);
1551 if (skb->pkt_type != PACKET_HOST)
1554 /* Count it even if it's bad */
1555 TCP_INC_STATS_BH(net, TCP_MIB_INSEGS);
1557 if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
1562 if (th->doff < sizeof(struct tcphdr) / 4)
1564 if (!pskb_may_pull(skb, th->doff * 4))
1567 /* An explanation is required here, I think.
1568 * Packet length and doff are validated by header prediction,
1569 * provided case of th->doff==0 is eliminated.
1570 * So, we defer the checks. */
1572 if (skb_checksum_init(skb, IPPROTO_TCP, inet_compute_pseudo))
1577 /* This is tricky : We move IPCB at its correct location into TCP_SKB_CB()
1578 * barrier() makes sure compiler wont play fool^Waliasing games.
1580 memmove(&TCP_SKB_CB(skb)->header.h4, IPCB(skb),
1581 sizeof(struct inet_skb_parm));
1584 TCP_SKB_CB(skb)->seq = ntohl(th->seq);
1585 TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
1586 skb->len - th->doff * 4);
1587 TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
1588 TCP_SKB_CB(skb)->tcp_flags = tcp_flag_byte(th);
1589 TCP_SKB_CB(skb)->tcp_tw_isn = 0;
1590 TCP_SKB_CB(skb)->ip_dsfield = ipv4_get_dsfield(iph);
1591 TCP_SKB_CB(skb)->sacked = 0;
1593 sk = __inet_lookup_skb(&tcp_hashinfo, skb, th->source, th->dest);
1598 if (sk->sk_state == TCP_TIME_WAIT)
1601 if (unlikely(iph->ttl < inet_sk(sk)->min_ttl)) {
1602 NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP);
1603 goto discard_and_relse;
1606 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
1607 goto discard_and_relse;
1609 #ifdef CONFIG_TCP_MD5SIG
1611 * We really want to reject the packet as early as possible
1613 * o We're expecting an MD5'd packet and this is no MD5 tcp option
1614 * o There is an MD5 option and we're not expecting one
1616 if (tcp_v4_inbound_md5_hash(sk, skb))
1617 goto discard_and_relse;
1622 if (sk_filter(sk, skb))
1623 goto discard_and_relse;
1625 sk_incoming_cpu_update(sk);
1628 bh_lock_sock_nested(sk);
1629 tcp_sk(sk)->segs_in += max_t(u16, 1, skb_shinfo(skb)->gso_segs);
1631 if (!sock_owned_by_user(sk)) {
1632 if (!tcp_prequeue(sk, skb))
1633 ret = tcp_v4_do_rcv(sk, skb);
1634 } else if (unlikely(sk_add_backlog(sk, skb,
1635 sk->sk_rcvbuf + sk->sk_sndbuf))) {
1637 NET_INC_STATS_BH(net, LINUX_MIB_TCPBACKLOGDROP);
1638 goto discard_and_relse;
1647 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
1650 if (tcp_checksum_complete(skb)) {
1652 TCP_INC_STATS_BH(net, TCP_MIB_CSUMERRORS);
1654 TCP_INC_STATS_BH(net, TCP_MIB_INERRS);
1656 tcp_v4_send_reset(NULL, skb);
1660 /* Discard frame. */
1669 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
1670 inet_twsk_put(inet_twsk(sk));
1674 if (tcp_checksum_complete(skb)) {
1675 inet_twsk_put(inet_twsk(sk));
1678 switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) {
1680 struct sock *sk2 = inet_lookup_listener(dev_net(skb->dev),
1682 iph->saddr, th->source,
1683 iph->daddr, th->dest,
1686 inet_twsk_deschedule_put(inet_twsk(sk));
1690 /* Fall through to ACK */
1693 tcp_v4_timewait_ack(sk, skb);
1697 case TCP_TW_SUCCESS:;
1702 static struct timewait_sock_ops tcp_timewait_sock_ops = {
1703 .twsk_obj_size = sizeof(struct tcp_timewait_sock),
1704 .twsk_unique = tcp_twsk_unique,
1705 .twsk_destructor= tcp_twsk_destructor,
1708 void inet_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb)
1710 struct dst_entry *dst = skb_dst(skb);
1714 sk->sk_rx_dst = dst;
1715 inet_sk(sk)->rx_dst_ifindex = skb->skb_iif;
1718 EXPORT_SYMBOL(inet_sk_rx_dst_set);
1720 const struct inet_connection_sock_af_ops ipv4_specific = {
1721 .queue_xmit = ip_queue_xmit,
1722 .send_check = tcp_v4_send_check,
1723 .rebuild_header = inet_sk_rebuild_header,
1724 .sk_rx_dst_set = inet_sk_rx_dst_set,
1725 .conn_request = tcp_v4_conn_request,
1726 .syn_recv_sock = tcp_v4_syn_recv_sock,
1727 .net_header_len = sizeof(struct iphdr),
1728 .setsockopt = ip_setsockopt,
1729 .getsockopt = ip_getsockopt,
1730 .addr2sockaddr = inet_csk_addr2sockaddr,
1731 .sockaddr_len = sizeof(struct sockaddr_in),
1732 .bind_conflict = inet_csk_bind_conflict,
1733 #ifdef CONFIG_COMPAT
1734 .compat_setsockopt = compat_ip_setsockopt,
1735 .compat_getsockopt = compat_ip_getsockopt,
1737 .mtu_reduced = tcp_v4_mtu_reduced,
1739 EXPORT_SYMBOL(ipv4_specific);
1741 #ifdef CONFIG_TCP_MD5SIG
1742 static const struct tcp_sock_af_ops tcp_sock_ipv4_specific = {
1743 .md5_lookup = tcp_v4_md5_lookup,
1744 .calc_md5_hash = tcp_v4_md5_hash_skb,
1745 .md5_parse = tcp_v4_parse_md5_keys,
1749 /* NOTE: A lot of things set to zero explicitly by call to
1750 * sk_alloc() so need not be done here.
1752 static int tcp_v4_init_sock(struct sock *sk)
1754 struct inet_connection_sock *icsk = inet_csk(sk);
1758 icsk->icsk_af_ops = &ipv4_specific;
1760 #ifdef CONFIG_TCP_MD5SIG
1761 tcp_sk(sk)->af_specific = &tcp_sock_ipv4_specific;
1767 void tcp_v4_destroy_sock(struct sock *sk)
1769 struct tcp_sock *tp = tcp_sk(sk);
1771 tcp_clear_xmit_timers(sk);
1773 tcp_cleanup_congestion_control(sk);
1775 /* Cleanup up the write buffer. */
1776 tcp_write_queue_purge(sk);
1778 /* Cleans up our, hopefully empty, out_of_order_queue. */
1779 __skb_queue_purge(&tp->out_of_order_queue);
1781 #ifdef CONFIG_TCP_MD5SIG
1782 /* Clean up the MD5 key list, if any */
1783 if (tp->md5sig_info) {
1784 tcp_clear_md5_list(sk);
1785 kfree_rcu(tp->md5sig_info, rcu);
1786 tp->md5sig_info = NULL;
1790 /* Clean prequeue, it must be empty really */
1791 __skb_queue_purge(&tp->ucopy.prequeue);
1793 /* Clean up a referenced TCP bind bucket. */
1794 if (inet_csk(sk)->icsk_bind_hash)
1797 BUG_ON(tp->fastopen_rsk);
1799 /* If socket is aborted during connect operation */
1800 tcp_free_fastopen_req(tp);
1801 tcp_saved_syn_free(tp);
1803 sk_sockets_allocated_dec(sk);
1804 sock_release_memcg(sk);
1806 EXPORT_SYMBOL(tcp_v4_destroy_sock);
1808 #ifdef CONFIG_PROC_FS
1809 /* Proc filesystem TCP sock list dumping. */
1812 * Get next listener socket follow cur. If cur is NULL, get first socket
1813 * starting from bucket given in st->bucket; when st->bucket is zero the
1814 * very first socket in the hash table is returned.
1816 static void *listening_get_next(struct seq_file *seq, void *cur)
1818 struct inet_connection_sock *icsk;
1819 struct hlist_nulls_node *node;
1820 struct sock *sk = cur;
1821 struct inet_listen_hashbucket *ilb;
1822 struct tcp_iter_state *st = seq->private;
1823 struct net *net = seq_file_net(seq);
1826 ilb = &tcp_hashinfo.listening_hash[st->bucket];
1827 spin_lock_bh(&ilb->lock);
1828 sk = sk_nulls_head(&ilb->head);
1832 ilb = &tcp_hashinfo.listening_hash[st->bucket];
1836 if (st->state == TCP_SEQ_STATE_OPENREQ) {
1837 struct request_sock *req = cur;
1839 icsk = inet_csk(st->syn_wait_sk);
1843 if (req->rsk_ops->family == st->family) {
1849 if (++st->sbucket >= icsk->icsk_accept_queue.listen_opt->nr_table_entries)
1852 req = icsk->icsk_accept_queue.listen_opt->syn_table[st->sbucket];
1854 sk = sk_nulls_next(st->syn_wait_sk);
1855 st->state = TCP_SEQ_STATE_LISTENING;
1856 spin_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
1858 icsk = inet_csk(sk);
1859 spin_lock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
1860 if (reqsk_queue_len(&icsk->icsk_accept_queue))
1862 spin_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
1863 sk = sk_nulls_next(sk);
1866 sk_nulls_for_each_from(sk, node) {
1867 if (!net_eq(sock_net(sk), net))
1869 if (sk->sk_family == st->family) {
1873 icsk = inet_csk(sk);
1874 spin_lock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
1875 if (reqsk_queue_len(&icsk->icsk_accept_queue)) {
1877 st->uid = sock_i_uid(sk);
1878 st->syn_wait_sk = sk;
1879 st->state = TCP_SEQ_STATE_OPENREQ;
1883 spin_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
1885 spin_unlock_bh(&ilb->lock);
1887 if (++st->bucket < INET_LHTABLE_SIZE) {
1888 ilb = &tcp_hashinfo.listening_hash[st->bucket];
1889 spin_lock_bh(&ilb->lock);
1890 sk = sk_nulls_head(&ilb->head);
1898 static void *listening_get_idx(struct seq_file *seq, loff_t *pos)
1900 struct tcp_iter_state *st = seq->private;
1905 rc = listening_get_next(seq, NULL);
1907 while (rc && *pos) {
1908 rc = listening_get_next(seq, rc);
1914 static inline bool empty_bucket(const struct tcp_iter_state *st)
1916 return hlist_nulls_empty(&tcp_hashinfo.ehash[st->bucket].chain);
1920 * Get first established socket starting from bucket given in st->bucket.
1921 * If st->bucket is zero, the very first socket in the hash is returned.
1923 static void *established_get_first(struct seq_file *seq)
1925 struct tcp_iter_state *st = seq->private;
1926 struct net *net = seq_file_net(seq);
1930 for (; st->bucket <= tcp_hashinfo.ehash_mask; ++st->bucket) {
1932 struct hlist_nulls_node *node;
1933 spinlock_t *lock = inet_ehash_lockp(&tcp_hashinfo, st->bucket);
1935 /* Lockless fast path for the common case of empty buckets */
1936 if (empty_bucket(st))
1940 sk_nulls_for_each(sk, node, &tcp_hashinfo.ehash[st->bucket].chain) {
1941 if (sk->sk_family != st->family ||
1942 !net_eq(sock_net(sk), net)) {
1948 spin_unlock_bh(lock);
1954 static void *established_get_next(struct seq_file *seq, void *cur)
1956 struct sock *sk = cur;
1957 struct hlist_nulls_node *node;
1958 struct tcp_iter_state *st = seq->private;
1959 struct net *net = seq_file_net(seq);
1964 sk = sk_nulls_next(sk);
1966 sk_nulls_for_each_from(sk, node) {
1967 if (sk->sk_family == st->family && net_eq(sock_net(sk), net))
1971 spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
1973 return established_get_first(seq);
1976 static void *established_get_idx(struct seq_file *seq, loff_t pos)
1978 struct tcp_iter_state *st = seq->private;
1982 rc = established_get_first(seq);
1985 rc = established_get_next(seq, rc);
1991 static void *tcp_get_idx(struct seq_file *seq, loff_t pos)
1994 struct tcp_iter_state *st = seq->private;
1996 st->state = TCP_SEQ_STATE_LISTENING;
1997 rc = listening_get_idx(seq, &pos);
2000 st->state = TCP_SEQ_STATE_ESTABLISHED;
2001 rc = established_get_idx(seq, pos);
2007 static void *tcp_seek_last_pos(struct seq_file *seq)
2009 struct tcp_iter_state *st = seq->private;
2010 int offset = st->offset;
2011 int orig_num = st->num;
2014 switch (st->state) {
2015 case TCP_SEQ_STATE_OPENREQ:
2016 case TCP_SEQ_STATE_LISTENING:
2017 if (st->bucket >= INET_LHTABLE_SIZE)
2019 st->state = TCP_SEQ_STATE_LISTENING;
2020 rc = listening_get_next(seq, NULL);
2021 while (offset-- && rc)
2022 rc = listening_get_next(seq, rc);
2026 st->state = TCP_SEQ_STATE_ESTABLISHED;
2028 case TCP_SEQ_STATE_ESTABLISHED:
2029 if (st->bucket > tcp_hashinfo.ehash_mask)
2031 rc = established_get_first(seq);
2032 while (offset-- && rc)
2033 rc = established_get_next(seq, rc);
2041 static void *tcp_seq_start(struct seq_file *seq, loff_t *pos)
2043 struct tcp_iter_state *st = seq->private;
2046 if (*pos && *pos == st->last_pos) {
2047 rc = tcp_seek_last_pos(seq);
2052 st->state = TCP_SEQ_STATE_LISTENING;
2056 rc = *pos ? tcp_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
2059 st->last_pos = *pos;
2063 static void *tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2065 struct tcp_iter_state *st = seq->private;
2068 if (v == SEQ_START_TOKEN) {
2069 rc = tcp_get_idx(seq, 0);
2073 switch (st->state) {
2074 case TCP_SEQ_STATE_OPENREQ:
2075 case TCP_SEQ_STATE_LISTENING:
2076 rc = listening_get_next(seq, v);
2078 st->state = TCP_SEQ_STATE_ESTABLISHED;
2081 rc = established_get_first(seq);
2084 case TCP_SEQ_STATE_ESTABLISHED:
2085 rc = established_get_next(seq, v);
2090 st->last_pos = *pos;
2094 static void tcp_seq_stop(struct seq_file *seq, void *v)
2096 struct tcp_iter_state *st = seq->private;
2098 switch (st->state) {
2099 case TCP_SEQ_STATE_OPENREQ:
2101 struct inet_connection_sock *icsk = inet_csk(st->syn_wait_sk);
2102 spin_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
2104 case TCP_SEQ_STATE_LISTENING:
2105 if (v != SEQ_START_TOKEN)
2106 spin_unlock_bh(&tcp_hashinfo.listening_hash[st->bucket].lock);
2108 case TCP_SEQ_STATE_ESTABLISHED:
2110 spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
2115 int tcp_seq_open(struct inode *inode, struct file *file)
2117 struct tcp_seq_afinfo *afinfo = PDE_DATA(inode);
2118 struct tcp_iter_state *s;
2121 err = seq_open_net(inode, file, &afinfo->seq_ops,
2122 sizeof(struct tcp_iter_state));
2126 s = ((struct seq_file *)file->private_data)->private;
2127 s->family = afinfo->family;
2131 EXPORT_SYMBOL(tcp_seq_open);
2133 int tcp_proc_register(struct net *net, struct tcp_seq_afinfo *afinfo)
2136 struct proc_dir_entry *p;
2138 afinfo->seq_ops.start = tcp_seq_start;
2139 afinfo->seq_ops.next = tcp_seq_next;
2140 afinfo->seq_ops.stop = tcp_seq_stop;
2142 p = proc_create_data(afinfo->name, S_IRUGO, net->proc_net,
2143 afinfo->seq_fops, afinfo);
2148 EXPORT_SYMBOL(tcp_proc_register);
2150 void tcp_proc_unregister(struct net *net, struct tcp_seq_afinfo *afinfo)
2152 remove_proc_entry(afinfo->name, net->proc_net);
2154 EXPORT_SYMBOL(tcp_proc_unregister);
2156 static void get_openreq4(const struct request_sock *req,
2157 struct seq_file *f, int i, kuid_t uid)
2159 const struct inet_request_sock *ireq = inet_rsk(req);
2160 long delta = req->rsk_timer.expires - jiffies;
2162 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2163 " %02X %08X:%08X %02X:%08lX %08X %5u %8d %u %d %pK",
2168 ntohs(ireq->ir_rmt_port),
2170 0, 0, /* could print option size, but that is af dependent. */
2171 1, /* timers active (only the expire timer) */
2172 jiffies_delta_to_clock_t(delta),
2174 from_kuid_munged(seq_user_ns(f), uid),
2175 0, /* non standard timer */
2176 0, /* open_requests have no inode */
2181 static void get_tcp4_sock(struct sock *sk, struct seq_file *f, int i)
2184 unsigned long timer_expires;
2185 const struct tcp_sock *tp = tcp_sk(sk);
2186 const struct inet_connection_sock *icsk = inet_csk(sk);
2187 const struct inet_sock *inet = inet_sk(sk);
2188 struct fastopen_queue *fastopenq = icsk->icsk_accept_queue.fastopenq;
2189 __be32 dest = inet->inet_daddr;
2190 __be32 src = inet->inet_rcv_saddr;
2191 __u16 destp = ntohs(inet->inet_dport);
2192 __u16 srcp = ntohs(inet->inet_sport);
2195 if (icsk->icsk_pending == ICSK_TIME_RETRANS ||
2196 icsk->icsk_pending == ICSK_TIME_EARLY_RETRANS ||
2197 icsk->icsk_pending == ICSK_TIME_LOSS_PROBE) {
2199 timer_expires = icsk->icsk_timeout;
2200 } else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
2202 timer_expires = icsk->icsk_timeout;
2203 } else if (timer_pending(&sk->sk_timer)) {
2205 timer_expires = sk->sk_timer.expires;
2208 timer_expires = jiffies;
2211 if (sk->sk_state == TCP_LISTEN)
2212 rx_queue = sk->sk_ack_backlog;
2215 * because we dont lock socket, we might find a transient negative value
2217 rx_queue = max_t(int, tp->rcv_nxt - tp->copied_seq, 0);
2219 seq_printf(f, "%4d: %08X:%04X %08X:%04X %02X %08X:%08X %02X:%08lX "
2220 "%08X %5u %8d %lu %d %pK %lu %lu %u %u %d",
2221 i, src, srcp, dest, destp, sk->sk_state,
2222 tp->write_seq - tp->snd_una,
2225 jiffies_delta_to_clock_t(timer_expires - jiffies),
2226 icsk->icsk_retransmits,
2227 from_kuid_munged(seq_user_ns(f), sock_i_uid(sk)),
2228 icsk->icsk_probes_out,
2230 atomic_read(&sk->sk_refcnt), sk,
2231 jiffies_to_clock_t(icsk->icsk_rto),
2232 jiffies_to_clock_t(icsk->icsk_ack.ato),
2233 (icsk->icsk_ack.quick << 1) | icsk->icsk_ack.pingpong,
2235 sk->sk_state == TCP_LISTEN ?
2236 (fastopenq ? fastopenq->max_qlen : 0) :
2237 (tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh));
2240 static void get_timewait4_sock(const struct inet_timewait_sock *tw,
2241 struct seq_file *f, int i)
2243 long delta = tw->tw_timer.expires - jiffies;
2247 dest = tw->tw_daddr;
2248 src = tw->tw_rcv_saddr;
2249 destp = ntohs(tw->tw_dport);
2250 srcp = ntohs(tw->tw_sport);
2252 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2253 " %02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK",
2254 i, src, srcp, dest, destp, tw->tw_substate, 0, 0,
2255 3, jiffies_delta_to_clock_t(delta), 0, 0, 0, 0,
2256 atomic_read(&tw->tw_refcnt), tw);
2261 static int tcp4_seq_show(struct seq_file *seq, void *v)
2263 struct tcp_iter_state *st;
2264 struct sock *sk = v;
2266 seq_setwidth(seq, TMPSZ - 1);
2267 if (v == SEQ_START_TOKEN) {
2268 seq_puts(seq, " sl local_address rem_address st tx_queue "
2269 "rx_queue tr tm->when retrnsmt uid timeout "
2275 switch (st->state) {
2276 case TCP_SEQ_STATE_LISTENING:
2277 case TCP_SEQ_STATE_ESTABLISHED:
2278 if (sk->sk_state == TCP_TIME_WAIT)
2279 get_timewait4_sock(v, seq, st->num);
2281 get_tcp4_sock(v, seq, st->num);
2283 case TCP_SEQ_STATE_OPENREQ:
2284 get_openreq4(v, seq, st->num, st->uid);
2292 static const struct file_operations tcp_afinfo_seq_fops = {
2293 .owner = THIS_MODULE,
2294 .open = tcp_seq_open,
2296 .llseek = seq_lseek,
2297 .release = seq_release_net
2300 static struct tcp_seq_afinfo tcp4_seq_afinfo = {
2303 .seq_fops = &tcp_afinfo_seq_fops,
2305 .show = tcp4_seq_show,
2309 static int __net_init tcp4_proc_init_net(struct net *net)
2311 return tcp_proc_register(net, &tcp4_seq_afinfo);
2314 static void __net_exit tcp4_proc_exit_net(struct net *net)
2316 tcp_proc_unregister(net, &tcp4_seq_afinfo);
2319 static struct pernet_operations tcp4_net_ops = {
2320 .init = tcp4_proc_init_net,
2321 .exit = tcp4_proc_exit_net,
2324 int __init tcp4_proc_init(void)
2326 return register_pernet_subsys(&tcp4_net_ops);
2329 void tcp4_proc_exit(void)
2331 unregister_pernet_subsys(&tcp4_net_ops);
2333 #endif /* CONFIG_PROC_FS */
2335 struct proto tcp_prot = {
2337 .owner = THIS_MODULE,
2339 .connect = tcp_v4_connect,
2340 .disconnect = tcp_disconnect,
2341 .accept = inet_csk_accept,
2343 .init = tcp_v4_init_sock,
2344 .destroy = tcp_v4_destroy_sock,
2345 .shutdown = tcp_shutdown,
2346 .setsockopt = tcp_setsockopt,
2347 .getsockopt = tcp_getsockopt,
2348 .recvmsg = tcp_recvmsg,
2349 .sendmsg = tcp_sendmsg,
2350 .sendpage = tcp_sendpage,
2351 .backlog_rcv = tcp_v4_do_rcv,
2352 .release_cb = tcp_release_cb,
2354 .unhash = inet_unhash,
2355 .get_port = inet_csk_get_port,
2356 .enter_memory_pressure = tcp_enter_memory_pressure,
2357 .stream_memory_free = tcp_stream_memory_free,
2358 .sockets_allocated = &tcp_sockets_allocated,
2359 .orphan_count = &tcp_orphan_count,
2360 .memory_allocated = &tcp_memory_allocated,
2361 .memory_pressure = &tcp_memory_pressure,
2362 .sysctl_mem = sysctl_tcp_mem,
2363 .sysctl_wmem = sysctl_tcp_wmem,
2364 .sysctl_rmem = sysctl_tcp_rmem,
2365 .max_header = MAX_TCP_HEADER,
2366 .obj_size = sizeof(struct tcp_sock),
2367 .slab_flags = SLAB_DESTROY_BY_RCU,
2368 .twsk_prot = &tcp_timewait_sock_ops,
2369 .rsk_prot = &tcp_request_sock_ops,
2370 .h.hashinfo = &tcp_hashinfo,
2371 .no_autobind = true,
2372 #ifdef CONFIG_COMPAT
2373 .compat_setsockopt = compat_tcp_setsockopt,
2374 .compat_getsockopt = compat_tcp_getsockopt,
2376 #ifdef CONFIG_MEMCG_KMEM
2377 .init_cgroup = tcp_init_cgroup,
2378 .destroy_cgroup = tcp_destroy_cgroup,
2379 .proto_cgroup = tcp_proto_cgroup,
2382 EXPORT_SYMBOL(tcp_prot);
2384 static void __net_exit tcp_sk_exit(struct net *net)
2388 for_each_possible_cpu(cpu)
2389 inet_ctl_sock_destroy(*per_cpu_ptr(net->ipv4.tcp_sk, cpu));
2390 free_percpu(net->ipv4.tcp_sk);
2393 static int __net_init tcp_sk_init(struct net *net)
2397 net->ipv4.tcp_sk = alloc_percpu(struct sock *);
2398 if (!net->ipv4.tcp_sk)
2401 for_each_possible_cpu(cpu) {
2404 res = inet_ctl_sock_create(&sk, PF_INET, SOCK_RAW,
2408 *per_cpu_ptr(net->ipv4.tcp_sk, cpu) = sk;
2411 net->ipv4.sysctl_tcp_ecn = 2;
2412 net->ipv4.sysctl_tcp_ecn_fallback = 1;
2414 net->ipv4.sysctl_tcp_base_mss = TCP_BASE_MSS;
2415 net->ipv4.sysctl_tcp_probe_threshold = TCP_PROBE_THRESHOLD;
2416 net->ipv4.sysctl_tcp_probe_interval = TCP_PROBE_INTERVAL;
2425 static void __net_exit tcp_sk_exit_batch(struct list_head *net_exit_list)
2427 inet_twsk_purge(&tcp_hashinfo, &tcp_death_row, AF_INET);
2430 static struct pernet_operations __net_initdata tcp_sk_ops = {
2431 .init = tcp_sk_init,
2432 .exit = tcp_sk_exit,
2433 .exit_batch = tcp_sk_exit_batch,
2436 void __init tcp_v4_init(void)
2438 inet_hashinfo_init(&tcp_hashinfo);
2439 if (register_pernet_subsys(&tcp_sk_ops))
2440 panic("Failed to create the TCP control socket.\n");