1/*
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.
5 *
6 * Implementation of the Transmission Control Protocol(TCP).
7 *
8 * IPv4 specific functions
9 *
10 *
11 * code split from:
12 * linux/ipv4/tcp.c
13 * linux/ipv4/tcp_input.c
14 * linux/ipv4/tcp_output.c
15 *
16 * See tcp.c for author information
17 *
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.
22 */
23
24/*
25 * Changes:
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
34 * ACK bit.
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
45 * coma.
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.
51 */
52
53#define pr_fmt(fmt) "TCP: " fmt
54
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>
65
66#include <net/net_namespace.h>
67#include <net/icmp.h>
68#include <net/inet_hashtables.h>
69#include <net/tcp.h>
70#include <net/transp_v6.h>
71#include <net/ipv6.h>
72#include <net/inet_common.h>
73#include <net/timewait_sock.h>
74#include <net/xfrm.h>
75#include <net/secure_seq.h>
76#include <net/busy_poll.h>
77
78#include <linux/inet.h>
79#include <linux/ipv6.h>
80#include <linux/stddef.h>
81#include <linux/proc_fs.h>
82#include <linux/seq_file.h>
83#include <linux/inetdevice.h>
84
85#include <crypto/hash.h>
86#include <linux/scatterlist.h>
87
88#include <trace/events/tcp.h>
89
90#ifdef CONFIG_TCP_MD5SIG
91static int tcp_v4_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key,
92 __be32 daddr, __be32 saddr, const struct tcphdr *th);
93#endif
94
95struct inet_hashinfo tcp_hashinfo;
96EXPORT_SYMBOL(tcp_hashinfo);
97
98static u32 tcp_v4_init_seq(const struct sk_buff *skb)
99{
100 return secure_tcp_seq(ip_hdr(skb)->daddr,
101 ip_hdr(skb)->saddr,
102 tcp_hdr(skb)->dest,
103 tcp_hdr(skb)->source);
104}
105
106static u32 tcp_v4_init_ts_off(const struct net *net, const struct sk_buff *skb)
107{
108 return secure_tcp_ts_off(net, ip_hdr(skb)->daddr, ip_hdr(skb)->saddr);
109}
110
111int tcp_twsk_unique(struct sock *sk, struct sock *sktw, void *twp)
112{
113 const struct tcp_timewait_sock *tcptw = tcp_twsk(sktw);
114 struct tcp_sock *tp = tcp_sk(sk);
115
116 /* With PAWS, it is safe from the viewpoint
117 of data integrity. Even without PAWS it is safe provided sequence
118 spaces do not overlap i.e. at data rates <= 80Mbit/sec.
119
120 Actually, the idea is close to VJ's one, only timestamp cache is
121 held not per host, but per port pair and TW bucket is used as state
122 holder.
123
124 If TW bucket has been already destroyed we fall back to VJ's scheme
125 and use initial timestamp retrieved from peer table.
126 */
127 if (tcptw->tw_ts_recent_stamp &&
128 (!twp || (sock_net(sk)->ipv4.sysctl_tcp_tw_reuse &&
129 get_seconds() - tcptw->tw_ts_recent_stamp > 1))) {
130 tp->write_seq = tcptw->tw_snd_nxt + 65535 + 2;
131 if (tp->write_seq == 0)
132 tp->write_seq = 1;
133 tp->rx_opt.ts_recent = tcptw->tw_ts_recent;
134 tp->rx_opt.ts_recent_stamp = tcptw->tw_ts_recent_stamp;
135 sock_hold(sktw);
136 return 1;
137 }
138
139 return 0;
140}
141EXPORT_SYMBOL_GPL(tcp_twsk_unique);
142
143/* This will initiate an outgoing connection. */
144int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
145{
146 struct sockaddr_in *usin = (struct sockaddr_in *)uaddr;
147 struct inet_sock *inet = inet_sk(sk);
148 struct tcp_sock *tp = tcp_sk(sk);
149 __be16 orig_sport, orig_dport;
150 __be32 daddr, nexthop;
151 struct flowi4 *fl4;
152 struct rtable *rt;
153 int err;
154 struct ip_options_rcu *inet_opt;
155 struct inet_timewait_death_row *tcp_death_row = &sock_net(sk)->ipv4.tcp_death_row;
156
157 if (addr_len < sizeof(struct sockaddr_in))
158 return -EINVAL;
159
160 if (usin->sin_family != AF_INET)
161 return -EAFNOSUPPORT;
162
163 nexthop = daddr = usin->sin_addr.s_addr;
164 inet_opt = rcu_dereference_protected(inet->inet_opt,
165 lockdep_sock_is_held(sk));
166 if (inet_opt && inet_opt->opt.srr) {
167 if (!daddr)
168 return -EINVAL;
169 nexthop = inet_opt->opt.faddr;
170 }
171
172 orig_sport = inet->inet_sport;
173 orig_dport = usin->sin_port;
174 fl4 = &inet->cork.fl.u.ip4;
175 rt = ip_route_connect(fl4, nexthop, inet->inet_saddr,
176 RT_CONN_FLAGS(sk), sk->sk_bound_dev_if,
177 IPPROTO_TCP,
178 orig_sport, orig_dport, sk);
179 if (IS_ERR(rt)) {
180 err = PTR_ERR(rt);
181 if (err == -ENETUNREACH)
182 IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTNOROUTES);
183 return err;
184 }
185
186 if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) {
187 ip_rt_put(rt);
188 return -ENETUNREACH;
189 }
190
191 if (!inet_opt || !inet_opt->opt.srr)
192 daddr = fl4->daddr;
193
194 if (!inet->inet_saddr)
195 inet->inet_saddr = fl4->saddr;
196 sk_rcv_saddr_set(sk, inet->inet_saddr);
197
198 if (tp->rx_opt.ts_recent_stamp && inet->inet_daddr != daddr) {
199 /* Reset inherited state */
200 tp->rx_opt.ts_recent = 0;
201 tp->rx_opt.ts_recent_stamp = 0;
202 if (likely(!tp->repair))
203 tp->write_seq = 0;
204 }
205
206 inet->inet_dport = usin->sin_port;
207 sk_daddr_set(sk, daddr);
208
209 inet_csk(sk)->icsk_ext_hdr_len = 0;
210 if (inet_opt)
211 inet_csk(sk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
212
213 tp->rx_opt.mss_clamp = TCP_MSS_DEFAULT;
214
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.
219 */
220 tcp_set_state(sk, TCP_SYN_SENT);
221 err = inet_hash_connect(tcp_death_row, sk);
222 if (err)
223 goto failure;
224
225 sk_set_txhash(sk);
226
227 rt = ip_route_newports(fl4, rt, orig_sport, orig_dport,
228 inet->inet_sport, inet->inet_dport, sk);
229 if (IS_ERR(rt)) {
230 err = PTR_ERR(rt);
231 rt = NULL;
232 goto failure;
233 }
234 /* OK, now commit destination to socket. */
235 sk->sk_gso_type = SKB_GSO_TCPV4;
236 sk_setup_caps(sk, &rt->dst);
237 rt = NULL;
238
239 if (likely(!tp->repair)) {
240 if (!tp->write_seq)
241 tp->write_seq = secure_tcp_seq(inet->inet_saddr,
242 inet->inet_daddr,
243 inet->inet_sport,
244 usin->sin_port);
245 tp->tsoffset = secure_tcp_ts_off(sock_net(sk),
246 inet->inet_saddr,
247 inet->inet_daddr);
248 }
249
250 inet->inet_id = tp->write_seq ^ jiffies;
251
252 if (tcp_fastopen_defer_connect(sk, &err))
253 return err;
254 if (err)
255 goto failure;
256
257 err = tcp_connect(sk);
258
259 if (err)
260 goto failure;
261
262 return 0;
263
264failure:
265 /*
266 * This unhashes the socket and releases the local port,
267 * if necessary.
268 */
269 tcp_set_state(sk, TCP_CLOSE);
270 ip_rt_put(rt);
271 sk->sk_route_caps = 0;
272 inet->inet_dport = 0;
273 return err;
274}
275EXPORT_SYMBOL(tcp_v4_connect);
276
277/*
278 * This routine reacts to ICMP_FRAG_NEEDED mtu indications as defined in RFC1191.
279 * It can be called through tcp_release_cb() if socket was owned by user
280 * at the time tcp_v4_err() was called to handle ICMP message.
281 */
282void tcp_v4_mtu_reduced(struct sock *sk)
283{
284 struct inet_sock *inet = inet_sk(sk);
285 struct dst_entry *dst;
286 u32 mtu;
287
288 if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE))
289 return;
290 mtu = tcp_sk(sk)->mtu_info;
291 dst = inet_csk_update_pmtu(sk, mtu);
292 if (!dst)
293 return;
294
295 /* Something is about to be wrong... Remember soft error
296 * for the case, if this connection will not able to recover.
297 */
298 if (mtu < dst_mtu(dst) && ip_dont_fragment(sk, dst))
299 sk->sk_err_soft = EMSGSIZE;
300
301 mtu = dst_mtu(dst);
302
303 if (inet->pmtudisc != IP_PMTUDISC_DONT &&
304 ip_sk_accept_pmtu(sk) &&
305 inet_csk(sk)->icsk_pmtu_cookie > mtu) {
306 tcp_sync_mss(sk, mtu);
307
308 /* Resend the TCP packet because it's
309 * clear that the old packet has been
310 * dropped. This is the new "fast" path mtu
311 * discovery.
312 */
313 tcp_simple_retransmit(sk);
314 } /* else let the usual retransmit timer handle it */
315}
316EXPORT_SYMBOL(tcp_v4_mtu_reduced);
317
318static void do_redirect(struct sk_buff *skb, struct sock *sk)
319{
320 struct dst_entry *dst = __sk_dst_check(sk, 0);
321
322 if (dst)
323 dst->ops->redirect(dst, sk, skb);
324}
325
326
327/* handle ICMP messages on TCP_NEW_SYN_RECV request sockets */
328void tcp_req_err(struct sock *sk, u32 seq, bool abort)
329{
330 struct request_sock *req = inet_reqsk(sk);
331 struct net *net = sock_net(sk);
332
333 /* ICMPs are not backlogged, hence we cannot get
334 * an established socket here.
335 */
336 if (seq != tcp_rsk(req)->snt_isn) {
337 __NET_INC_STATS(net, LINUX_MIB_OUTOFWINDOWICMPS);
338 } else if (abort) {
339 /*
340 * Still in SYN_RECV, just remove it silently.
341 * There is no good way to pass the error to the newly
342 * created socket, and POSIX does not want network
343 * errors returned from accept().
344 */
345 inet_csk_reqsk_queue_drop(req->rsk_listener, req);
346 tcp_listendrop(req->rsk_listener);
347 }
348 reqsk_put(req);
349}
350EXPORT_SYMBOL(tcp_req_err);
351
352/*
353 * This routine is called by the ICMP module when it gets some
354 * sort of error condition. If err < 0 then the socket should
355 * be closed and the error returned to the user. If err > 0
356 * it's just the icmp type << 8 | icmp code. After adjustment
357 * header points to the first 8 bytes of the tcp header. We need
358 * to find the appropriate port.
359 *
360 * The locking strategy used here is very "optimistic". When
361 * someone else accesses the socket the ICMP is just dropped
362 * and for some paths there is no check at all.
363 * A more general error queue to queue errors for later handling
364 * is probably better.
365 *
366 */
367
368void tcp_v4_err(struct sk_buff *icmp_skb, u32 info)
369{
370 const struct iphdr *iph = (const struct iphdr *)icmp_skb->data;
371 struct tcphdr *th = (struct tcphdr *)(icmp_skb->data + (iph->ihl << 2));
372 struct inet_connection_sock *icsk;
373 struct tcp_sock *tp;
374 struct inet_sock *inet;
375 const int type = icmp_hdr(icmp_skb)->type;
376 const int code = icmp_hdr(icmp_skb)->code;
377 struct sock *sk;
378 struct sk_buff *skb;
379 struct request_sock *fastopen;
380 u32 seq, snd_una;
381 s32 remaining;
382 u32 delta_us;
383 int err;
384 struct net *net = dev_net(icmp_skb->dev);
385
386 sk = __inet_lookup_established(net, &tcp_hashinfo, iph->daddr,
387 th->dest, iph->saddr, ntohs(th->source),
388 inet_iif(icmp_skb), 0);
389 if (!sk) {
390 __ICMP_INC_STATS(net, ICMP_MIB_INERRORS);
391 return;
392 }
393 if (sk->sk_state == TCP_TIME_WAIT) {
394 inet_twsk_put(inet_twsk(sk));
395 return;
396 }
397 seq = ntohl(th->seq);
398 if (sk->sk_state == TCP_NEW_SYN_RECV)
399 return tcp_req_err(sk, seq,
400 type == ICMP_PARAMETERPROB ||
401 type == ICMP_TIME_EXCEEDED ||
402 (type == ICMP_DEST_UNREACH &&
403 (code == ICMP_NET_UNREACH ||
404 code == ICMP_HOST_UNREACH)));
405
406 bh_lock_sock(sk);
407 /* If too many ICMPs get dropped on busy
408 * servers this needs to be solved differently.
409 * We do take care of PMTU discovery (RFC1191) special case :
410 * we can receive locally generated ICMP messages while socket is held.
411 */
412 if (sock_owned_by_user(sk)) {
413 if (!(type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED))
414 __NET_INC_STATS(net, LINUX_MIB_LOCKDROPPEDICMPS);
415 }
416 if (sk->sk_state == TCP_CLOSE)
417 goto out;
418
419 if (unlikely(iph->ttl < inet_sk(sk)->min_ttl)) {
420 __NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP);
421 goto out;
422 }
423
424 icsk = inet_csk(sk);
425 tp = tcp_sk(sk);
426 /* XXX (TFO) - tp->snd_una should be ISN (tcp_create_openreq_child() */
427 fastopen = tp->fastopen_rsk;
428 snd_una = fastopen ? tcp_rsk(fastopen)->snt_isn : tp->snd_una;
429 if (sk->sk_state != TCP_LISTEN &&
430 !between(seq, snd_una, tp->snd_nxt)) {
431 __NET_INC_STATS(net, LINUX_MIB_OUTOFWINDOWICMPS);
432 goto out;
433 }
434
435 switch (type) {
436 case ICMP_REDIRECT:
437 if (!sock_owned_by_user(sk))
438 do_redirect(icmp_skb, sk);
439 goto out;
440 case ICMP_SOURCE_QUENCH:
441 /* Just silently ignore these. */
442 goto out;
443 case ICMP_PARAMETERPROB:
444 err = EPROTO;
445 break;
446 case ICMP_DEST_UNREACH:
447 if (code > NR_ICMP_UNREACH)
448 goto out;
449
450 if (code == ICMP_FRAG_NEEDED) { /* PMTU discovery (RFC1191) */
451 /* We are not interested in TCP_LISTEN and open_requests
452 * (SYN-ACKs send out by Linux are always <576bytes so
453 * they should go through unfragmented).
454 */
455 if (sk->sk_state == TCP_LISTEN)
456 goto out;
457
458 tp->mtu_info = info;
459 if (!sock_owned_by_user(sk)) {
460 tcp_v4_mtu_reduced(sk);
461 } else {
462 if (!test_and_set_bit(TCP_MTU_REDUCED_DEFERRED, &sk->sk_tsq_flags))
463 sock_hold(sk);
464 }
465 goto out;
466 }
467
468 err = icmp_err_convert[code].errno;
469 /* check if icmp_skb allows revert of backoff
470 * (see draft-zimmermann-tcp-lcd) */
471 if (code != ICMP_NET_UNREACH && code != ICMP_HOST_UNREACH)
472 break;
473 if (seq != tp->snd_una || !icsk->icsk_retransmits ||
474 !icsk->icsk_backoff || fastopen)
475 break;
476
477 if (sock_owned_by_user(sk))
478 break;
479
480 icsk->icsk_backoff--;
481 icsk->icsk_rto = tp->srtt_us ? __tcp_set_rto(tp) :
482 TCP_TIMEOUT_INIT;
483 icsk->icsk_rto = inet_csk_rto_backoff(icsk, TCP_RTO_MAX);
484
485 skb = tcp_rtx_queue_head(sk);
486 BUG_ON(!skb);
487
488 tcp_mstamp_refresh(tp);
489 delta_us = (u32)(tp->tcp_mstamp - skb->skb_mstamp);
490 remaining = icsk->icsk_rto -
491 usecs_to_jiffies(delta_us);
492
493 if (remaining > 0) {
494 inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
495 remaining, TCP_RTO_MAX);
496 } else {
497 /* RTO revert clocked out retransmission.
498 * Will retransmit now */
499 tcp_retransmit_timer(sk);
500 }
501
502 break;
503 case ICMP_TIME_EXCEEDED:
504 err = EHOSTUNREACH;
505 break;
506 default:
507 goto out;
508 }
509
510 switch (sk->sk_state) {
511 case TCP_SYN_SENT:
512 case TCP_SYN_RECV:
513 /* Only in fast or simultaneous open. If a fast open socket is
514 * is already accepted it is treated as a connected one below.
515 */
516 if (fastopen && !fastopen->sk)
517 break;
518
519 if (!sock_owned_by_user(sk)) {
520 sk->sk_err = err;
521
522 sk->sk_error_report(sk);
523
524 tcp_done(sk);
525 } else {
526 sk->sk_err_soft = err;
527 }
528 goto out;
529 }
530
531 /* If we've already connected we will keep trying
532 * until we time out, or the user gives up.
533 *
534 * rfc1122 4.2.3.9 allows to consider as hard errors
535 * only PROTO_UNREACH and PORT_UNREACH (well, FRAG_FAILED too,
536 * but it is obsoleted by pmtu discovery).
537 *
538 * Note, that in modern internet, where routing is unreliable
539 * and in each dark corner broken firewalls sit, sending random
540 * errors ordered by their masters even this two messages finally lose
541 * their original sense (even Linux sends invalid PORT_UNREACHs)
542 *
543 * Now we are in compliance with RFCs.
544 * --ANK (980905)
545 */
546
547 inet = inet_sk(sk);
548 if (!sock_owned_by_user(sk) && inet->recverr) {
549 sk->sk_err = err;
550 sk->sk_error_report(sk);
551 } else { /* Only an error on timeout */
552 sk->sk_err_soft = err;
553 }
554
555out:
556 bh_unlock_sock(sk);
557 sock_put(sk);
558}
559
560void __tcp_v4_send_check(struct sk_buff *skb, __be32 saddr, __be32 daddr)
561{
562 struct tcphdr *th = tcp_hdr(skb);
563
564 if (skb->ip_summed == CHECKSUM_PARTIAL) {
565 th->check = ~tcp_v4_check(skb->len, saddr, daddr, 0);
566 skb->csum_start = skb_transport_header(skb) - skb->head;
567 skb->csum_offset = offsetof(struct tcphdr, check);
568 } else {
569 th->check = tcp_v4_check(skb->len, saddr, daddr,
570 csum_partial(th,
571 th->doff << 2,
572 skb->csum));
573 }
574}
575
576/* This routine computes an IPv4 TCP checksum. */
577void tcp_v4_send_check(struct sock *sk, struct sk_buff *skb)
578{
579 const struct inet_sock *inet = inet_sk(sk);
580
581 __tcp_v4_send_check(skb, inet->inet_saddr, inet->inet_daddr);
582}
583EXPORT_SYMBOL(tcp_v4_send_check);
584
585/*
586 * This routine will send an RST to the other tcp.
587 *
588 * Someone asks: why I NEVER use socket parameters (TOS, TTL etc.)
589 * for reset.
590 * Answer: if a packet caused RST, it is not for a socket
591 * existing in our system, if it is matched to a socket,
592 * it is just duplicate segment or bug in other side's TCP.
593 * So that we build reply only basing on parameters
594 * arrived with segment.
595 * Exception: precedence violation. We do not implement it in any case.
596 */
597
598static void tcp_v4_send_reset(const struct sock *sk, struct sk_buff *skb)
599{
600 const struct tcphdr *th = tcp_hdr(skb);
601 struct {
602 struct tcphdr th;
603#ifdef CONFIG_TCP_MD5SIG
604 __be32 opt[(TCPOLEN_MD5SIG_ALIGNED >> 2)];
605#endif
606 } rep;
607 struct ip_reply_arg arg;
608#ifdef CONFIG_TCP_MD5SIG
609 struct tcp_md5sig_key *key = NULL;
610 const __u8 *hash_location = NULL;
611 unsigned char newhash[16];
612 int genhash;
613 struct sock *sk1 = NULL;
614#endif
615 struct net *net;
616
617 /* Never send a reset in response to a reset. */
618 if (th->rst)
619 return;
620
621 /* If sk not NULL, it means we did a successful lookup and incoming
622 * route had to be correct. prequeue might have dropped our dst.
623 */
624 if (!sk && skb_rtable(skb)->rt_type != RTN_LOCAL)
625 return;
626
627 /* Swap the send and the receive. */
628 memset(&rep, 0, sizeof(rep));
629 rep.th.dest = th->source;
630 rep.th.source = th->dest;
631 rep.th.doff = sizeof(struct tcphdr) / 4;
632 rep.th.rst = 1;
633
634 if (th->ack) {
635 rep.th.seq = th->ack_seq;
636 } else {
637 rep.th.ack = 1;
638 rep.th.ack_seq = htonl(ntohl(th->seq) + th->syn + th->fin +
639 skb->len - (th->doff << 2));
640 }
641
642 memset(&arg, 0, sizeof(arg));
643 arg.iov[0].iov_base = (unsigned char *)&rep;
644 arg.iov[0].iov_len = sizeof(rep.th);
645
646 net = sk ? sock_net(sk) : dev_net(skb_dst(skb)->dev);
647#ifdef CONFIG_TCP_MD5SIG
648 rcu_read_lock();
649 hash_location = tcp_parse_md5sig_option(th);
650 if (sk && sk_fullsock(sk)) {
651 key = tcp_md5_do_lookup(sk, (union tcp_md5_addr *)
652 &ip_hdr(skb)->saddr, AF_INET);
653 } else if (hash_location) {
654 /*
655 * active side is lost. Try to find listening socket through
656 * source port, and then find md5 key through listening socket.
657 * we are not loose security here:
658 * Incoming packet is checked with md5 hash with finding key,
659 * no RST generated if md5 hash doesn't match.
660 */
661 sk1 = __inet_lookup_listener(net, &tcp_hashinfo, NULL, 0,
662 ip_hdr(skb)->saddr,
663 th->source, ip_hdr(skb)->daddr,
664 ntohs(th->source), inet_iif(skb),
665 tcp_v4_sdif(skb));
666 /* don't send rst if it can't find key */
667 if (!sk1)
668 goto out;
669
670 key = tcp_md5_do_lookup(sk1, (union tcp_md5_addr *)
671 &ip_hdr(skb)->saddr, AF_INET);
672 if (!key)
673 goto out;
674
675
676 genhash = tcp_v4_md5_hash_skb(newhash, key, NULL, skb);
677 if (genhash || memcmp(hash_location, newhash, 16) != 0)
678 goto out;
679
680 }
681
682 if (key) {
683 rep.opt[0] = htonl((TCPOPT_NOP << 24) |
684 (TCPOPT_NOP << 16) |
685 (TCPOPT_MD5SIG << 8) |
686 TCPOLEN_MD5SIG);
687 /* Update length and the length the header thinks exists */
688 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED;
689 rep.th.doff = arg.iov[0].iov_len / 4;
690
691 tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[1],
692 key, ip_hdr(skb)->saddr,
693 ip_hdr(skb)->daddr, &rep.th);
694 }
695#endif
696 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
697 ip_hdr(skb)->saddr, /* XXX */
698 arg.iov[0].iov_len, IPPROTO_TCP, 0);
699 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
700 arg.flags = (sk && inet_sk_transparent(sk)) ? IP_REPLY_ARG_NOSRCCHECK : 0;
701
702 /* When socket is gone, all binding information is lost.
703 * routing might fail in this case. No choice here, if we choose to force
704 * input interface, we will misroute in case of asymmetric route.
705 */
706 if (sk) {
707 arg.bound_dev_if = sk->sk_bound_dev_if;
708 if (sk_fullsock(sk))
709 trace_tcp_send_reset(sk, skb);
710 }
711
712 BUILD_BUG_ON(offsetof(struct sock, sk_bound_dev_if) !=
713 offsetof(struct inet_timewait_sock, tw_bound_dev_if));
714
715 arg.tos = ip_hdr(skb)->tos;
716 arg.uid = sock_net_uid(net, sk && sk_fullsock(sk) ? sk : NULL);
717 local_bh_disable();
718 ip_send_unicast_reply(*this_cpu_ptr(net->ipv4.tcp_sk),
719 skb, &TCP_SKB_CB(skb)->header.h4.opt,
720 ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
721 &arg, arg.iov[0].iov_len);
722
723 __TCP_INC_STATS(net, TCP_MIB_OUTSEGS);
724 __TCP_INC_STATS(net, TCP_MIB_OUTRSTS);
725 local_bh_enable();
726
727#ifdef CONFIG_TCP_MD5SIG
728out:
729 rcu_read_unlock();
730#endif
731}
732
733/* The code following below sending ACKs in SYN-RECV and TIME-WAIT states
734 outside socket context is ugly, certainly. What can I do?
735 */
736
737static void tcp_v4_send_ack(const struct sock *sk,
738 struct sk_buff *skb, u32 seq, u32 ack,
739 u32 win, u32 tsval, u32 tsecr, int oif,
740 struct tcp_md5sig_key *key,
741 int reply_flags, u8 tos)
742{
743 const struct tcphdr *th = tcp_hdr(skb);
744 struct {
745 struct tcphdr th;
746 __be32 opt[(TCPOLEN_TSTAMP_ALIGNED >> 2)
747#ifdef CONFIG_TCP_MD5SIG
748 + (TCPOLEN_MD5SIG_ALIGNED >> 2)
749#endif
750 ];
751 } rep;
752 struct net *net = sock_net(sk);
753 struct ip_reply_arg arg;
754
755 memset(&rep.th, 0, sizeof(struct tcphdr));
756 memset(&arg, 0, sizeof(arg));
757
758 arg.iov[0].iov_base = (unsigned char *)&rep;
759 arg.iov[0].iov_len = sizeof(rep.th);
760 if (tsecr) {
761 rep.opt[0] = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
762 (TCPOPT_TIMESTAMP << 8) |
763 TCPOLEN_TIMESTAMP);
764 rep.opt[1] = htonl(tsval);
765 rep.opt[2] = htonl(tsecr);
766 arg.iov[0].iov_len += TCPOLEN_TSTAMP_ALIGNED;
767 }
768
769 /* Swap the send and the receive. */
770 rep.th.dest = th->source;
771 rep.th.source = th->dest;
772 rep.th.doff = arg.iov[0].iov_len / 4;
773 rep.th.seq = htonl(seq);
774 rep.th.ack_seq = htonl(ack);
775 rep.th.ack = 1;
776 rep.th.window = htons(win);
777
778#ifdef CONFIG_TCP_MD5SIG
779 if (key) {
780 int offset = (tsecr) ? 3 : 0;
781
782 rep.opt[offset++] = htonl((TCPOPT_NOP << 24) |
783 (TCPOPT_NOP << 16) |
784 (TCPOPT_MD5SIG << 8) |
785 TCPOLEN_MD5SIG);
786 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED;
787 rep.th.doff = arg.iov[0].iov_len/4;
788
789 tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[offset],
790 key, ip_hdr(skb)->saddr,
791 ip_hdr(skb)->daddr, &rep.th);
792 }
793#endif
794 arg.flags = reply_flags;
795 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
796 ip_hdr(skb)->saddr, /* XXX */
797 arg.iov[0].iov_len, IPPROTO_TCP, 0);
798 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
799 if (oif)
800 arg.bound_dev_if = oif;
801 arg.tos = tos;
802 arg.uid = sock_net_uid(net, sk_fullsock(sk) ? sk : NULL);
803 local_bh_disable();
804 ip_send_unicast_reply(*this_cpu_ptr(net->ipv4.tcp_sk),
805 skb, &TCP_SKB_CB(skb)->header.h4.opt,
806 ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
807 &arg, arg.iov[0].iov_len);
808
809 __TCP_INC_STATS(net, TCP_MIB_OUTSEGS);
810 local_bh_enable();
811}
812
813static void tcp_v4_timewait_ack(struct sock *sk, struct sk_buff *skb)
814{
815 struct inet_timewait_sock *tw = inet_twsk(sk);
816 struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
817
818 tcp_v4_send_ack(sk, skb,
819 tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
820 tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
821 tcp_time_stamp_raw() + tcptw->tw_ts_offset,
822 tcptw->tw_ts_recent,
823 tw->tw_bound_dev_if,
824 tcp_twsk_md5_key(tcptw),
825 tw->tw_transparent ? IP_REPLY_ARG_NOSRCCHECK : 0,
826 tw->tw_tos
827 );
828
829 inet_twsk_put(tw);
830}
831
832static void tcp_v4_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb,
833 struct request_sock *req)
834{
835 /* sk->sk_state == TCP_LISTEN -> for regular TCP_SYN_RECV
836 * sk->sk_state == TCP_SYN_RECV -> for Fast Open.
837 */
838 u32 seq = (sk->sk_state == TCP_LISTEN) ? tcp_rsk(req)->snt_isn + 1 :
839 tcp_sk(sk)->snd_nxt;
840
841 /* RFC 7323 2.3
842 * The window field (SEG.WND) of every outgoing segment, with the
843 * exception of <SYN> segments, MUST be right-shifted by
844 * Rcv.Wind.Shift bits:
845 */
846 tcp_v4_send_ack(sk, skb, seq,
847 tcp_rsk(req)->rcv_nxt,
848 req->rsk_rcv_wnd >> inet_rsk(req)->rcv_wscale,
849 tcp_time_stamp_raw() + tcp_rsk(req)->ts_off,
850 req->ts_recent,
851 0,
852 tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&ip_hdr(skb)->saddr,
853 AF_INET),
854 inet_rsk(req)->no_srccheck ? IP_REPLY_ARG_NOSRCCHECK : 0,
855 ip_hdr(skb)->tos);
856}
857
858/*
859 * Send a SYN-ACK after having received a SYN.
860 * This still operates on a request_sock only, not on a big
861 * socket.
862 */
863static int tcp_v4_send_synack(const struct sock *sk, struct dst_entry *dst,
864 struct flowi *fl,
865 struct request_sock *req,
866 struct tcp_fastopen_cookie *foc,
867 enum tcp_synack_type synack_type)
868{
869 const struct inet_request_sock *ireq = inet_rsk(req);
870 struct flowi4 fl4;
871 int err = -1;
872 struct sk_buff *skb;
873
874 /* First, grab a route. */
875 if (!dst && (dst = inet_csk_route_req(sk, &fl4, req)) == NULL)
876 return -1;
877
878 skb = tcp_make_synack(sk, dst, req, foc, synack_type);
879
880 if (skb) {
881 __tcp_v4_send_check(skb, ireq->ir_loc_addr, ireq->ir_rmt_addr);
882
883 err = ip_build_and_send_pkt(skb, sk, ireq->ir_loc_addr,
884 ireq->ir_rmt_addr,
885 ireq_opt_deref(ireq));
886 err = net_xmit_eval(err);
887 }
888
889 return err;
890}
891
892/*
893 * IPv4 request_sock destructor.
894 */
895static void tcp_v4_reqsk_destructor(struct request_sock *req)
896{
897 kfree(rcu_dereference_protected(inet_rsk(req)->ireq_opt, 1));
898}
899
900#ifdef CONFIG_TCP_MD5SIG
901/*
902 * RFC2385 MD5 checksumming requires a mapping of
903 * IP address->MD5 Key.
904 * We need to maintain these in the sk structure.
905 */
906
907/* Find the Key structure for an address. */
908struct tcp_md5sig_key *tcp_md5_do_lookup(const struct sock *sk,
909 const union tcp_md5_addr *addr,
910 int family)
911{
912 const struct tcp_sock *tp = tcp_sk(sk);
913 struct tcp_md5sig_key *key;
914 const struct tcp_md5sig_info *md5sig;
915 __be32 mask;
916 struct tcp_md5sig_key *best_match = NULL;
917 bool match;
918
919 /* caller either holds rcu_read_lock() or socket lock */
920 md5sig = rcu_dereference_check(tp->md5sig_info,
921 lockdep_sock_is_held(sk));
922 if (!md5sig)
923 return NULL;
924
925 hlist_for_each_entry_rcu(key, &md5sig->head, node) {
926 if (key->family != family)
927 continue;
928
929 if (family == AF_INET) {
930 mask = inet_make_mask(key->prefixlen);
931 match = (key->addr.a4.s_addr & mask) ==
932 (addr->a4.s_addr & mask);
933#if IS_ENABLED(CONFIG_IPV6)
934 } else if (family == AF_INET6) {
935 match = ipv6_prefix_equal(&key->addr.a6, &addr->a6,
936 key->prefixlen);
937#endif
938 } else {
939 match = false;
940 }
941
942 if (match && (!best_match ||
943 key->prefixlen > best_match->prefixlen))
944 best_match = key;
945 }
946 return best_match;
947}
948EXPORT_SYMBOL(tcp_md5_do_lookup);
949
950static struct tcp_md5sig_key *tcp_md5_do_lookup_exact(const struct sock *sk,
951 const union tcp_md5_addr *addr,
952 int family, u8 prefixlen)
953{
954 const struct tcp_sock *tp = tcp_sk(sk);
955 struct tcp_md5sig_key *key;
956 unsigned int size = sizeof(struct in_addr);
957 const struct tcp_md5sig_info *md5sig;
958
959 /* caller either holds rcu_read_lock() or socket lock */
960 md5sig = rcu_dereference_check(tp->md5sig_info,
961 lockdep_sock_is_held(sk));
962 if (!md5sig)
963 return NULL;
964#if IS_ENABLED(CONFIG_IPV6)
965 if (family == AF_INET6)
966 size = sizeof(struct in6_addr);
967#endif
968 hlist_for_each_entry_rcu(key, &md5sig->head, node) {
969 if (key->family != family)
970 continue;
971 if (!memcmp(&key->addr, addr, size) &&
972 key->prefixlen == prefixlen)
973 return key;
974 }
975 return NULL;
976}
977
978struct tcp_md5sig_key *tcp_v4_md5_lookup(const struct sock *sk,
979 const struct sock *addr_sk)
980{
981 const union tcp_md5_addr *addr;
982
983 addr = (const union tcp_md5_addr *)&addr_sk->sk_daddr;
984 return tcp_md5_do_lookup(sk, addr, AF_INET);
985}
986EXPORT_SYMBOL(tcp_v4_md5_lookup);
987
988/* This can be called on a newly created socket, from other files */
989int tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr,
990 int family, u8 prefixlen, const u8 *newkey, u8 newkeylen,
991 gfp_t gfp)
992{
993 /* Add Key to the list */
994 struct tcp_md5sig_key *key;
995 struct tcp_sock *tp = tcp_sk(sk);
996 struct tcp_md5sig_info *md5sig;
997
998 key = tcp_md5_do_lookup_exact(sk, addr, family, prefixlen);
999 if (key) {
1000 /* Pre-existing entry - just update that one. */
1001 memcpy(key->key, newkey, newkeylen);
1002 key->keylen = newkeylen;
1003 return 0;
1004 }
1005
1006 md5sig = rcu_dereference_protected(tp->md5sig_info,
1007 lockdep_sock_is_held(sk));
1008 if (!md5sig) {
1009 md5sig = kmalloc(sizeof(*md5sig), gfp);
1010 if (!md5sig)
1011 return -ENOMEM;
1012
1013 sk_nocaps_add(sk, NETIF_F_GSO_MASK);
1014 INIT_HLIST_HEAD(&md5sig->head);
1015 rcu_assign_pointer(tp->md5sig_info, md5sig);
1016 }
1017
1018 key = sock_kmalloc(sk, sizeof(*key), gfp);
1019 if (!key)
1020 return -ENOMEM;
1021 if (!tcp_alloc_md5sig_pool()) {
1022 sock_kfree_s(sk, key, sizeof(*key));
1023 return -ENOMEM;
1024 }
1025
1026 memcpy(key->key, newkey, newkeylen);
1027 key->keylen = newkeylen;
1028 key->family = family;
1029 key->prefixlen = prefixlen;
1030 memcpy(&key->addr, addr,
1031 (family == AF_INET6) ? sizeof(struct in6_addr) :
1032 sizeof(struct in_addr));
1033 hlist_add_head_rcu(&key->node, &md5sig->head);
1034 return 0;
1035}
1036EXPORT_SYMBOL(tcp_md5_do_add);
1037
1038int tcp_md5_do_del(struct sock *sk, const union tcp_md5_addr *addr, int family,
1039 u8 prefixlen)
1040{
1041 struct tcp_md5sig_key *key;
1042
1043 key = tcp_md5_do_lookup_exact(sk, addr, family, prefixlen);
1044 if (!key)
1045 return -ENOENT;
1046 hlist_del_rcu(&key->node);
1047 atomic_sub(sizeof(*key), &sk->sk_omem_alloc);
1048 kfree_rcu(key, rcu);
1049 return 0;
1050}
1051EXPORT_SYMBOL(tcp_md5_do_del);
1052
1053static void tcp_clear_md5_list(struct sock *sk)
1054{
1055 struct tcp_sock *tp = tcp_sk(sk);
1056 struct tcp_md5sig_key *key;
1057 struct hlist_node *n;
1058 struct tcp_md5sig_info *md5sig;
1059
1060 md5sig = rcu_dereference_protected(tp->md5sig_info, 1);
1061
1062 hlist_for_each_entry_safe(key, n, &md5sig->head, node) {
1063 hlist_del_rcu(&key->node);
1064 atomic_sub(sizeof(*key), &sk->sk_omem_alloc);
1065 kfree_rcu(key, rcu);
1066 }
1067}
1068
1069static int tcp_v4_parse_md5_keys(struct sock *sk, int optname,
1070 char __user *optval, int optlen)
1071{
1072 struct tcp_md5sig cmd;
1073 struct sockaddr_in *sin = (struct sockaddr_in *)&cmd.tcpm_addr;
1074 u8 prefixlen = 32;
1075
1076 if (optlen < sizeof(cmd))
1077 return -EINVAL;
1078
1079 if (copy_from_user(&cmd, optval, sizeof(cmd)))
1080 return -EFAULT;
1081
1082 if (sin->sin_family != AF_INET)
1083 return -EINVAL;
1084
1085 if (optname == TCP_MD5SIG_EXT &&
1086 cmd.tcpm_flags & TCP_MD5SIG_FLAG_PREFIX) {
1087 prefixlen = cmd.tcpm_prefixlen;
1088 if (prefixlen > 32)
1089 return -EINVAL;
1090 }
1091
1092 if (!cmd.tcpm_keylen)
1093 return tcp_md5_do_del(sk, (union tcp_md5_addr *)&sin->sin_addr.s_addr,
1094 AF_INET, prefixlen);
1095
1096 if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN)
1097 return -EINVAL;
1098
1099 return tcp_md5_do_add(sk, (union tcp_md5_addr *)&sin->sin_addr.s_addr,
1100 AF_INET, prefixlen, cmd.tcpm_key, cmd.tcpm_keylen,
1101 GFP_KERNEL);
1102}
1103
1104static int tcp_v4_md5_hash_headers(struct tcp_md5sig_pool *hp,
1105 __be32 daddr, __be32 saddr,
1106 const struct tcphdr *th, int nbytes)
1107{
1108 struct tcp4_pseudohdr *bp;
1109 struct scatterlist sg;
1110 struct tcphdr *_th;
1111
1112 bp = hp->scratch;
1113 bp->saddr = saddr;
1114 bp->daddr = daddr;
1115 bp->pad = 0;
1116 bp->protocol = IPPROTO_TCP;
1117 bp->len = cpu_to_be16(nbytes);
1118
1119 _th = (struct tcphdr *)(bp + 1);
1120 memcpy(_th, th, sizeof(*th));
1121 _th->check = 0;
1122
1123 sg_init_one(&sg, bp, sizeof(*bp) + sizeof(*th));
1124 ahash_request_set_crypt(hp->md5_req, &sg, NULL,
1125 sizeof(*bp) + sizeof(*th));
1126 return crypto_ahash_update(hp->md5_req);
1127}
1128
1129static int tcp_v4_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key,
1130 __be32 daddr, __be32 saddr, const struct tcphdr *th)
1131{
1132 struct tcp_md5sig_pool *hp;
1133 struct ahash_request *req;
1134
1135 hp = tcp_get_md5sig_pool();
1136 if (!hp)
1137 goto clear_hash_noput;
1138 req = hp->md5_req;
1139
1140 if (crypto_ahash_init(req))
1141 goto clear_hash;
1142 if (tcp_v4_md5_hash_headers(hp, daddr, saddr, th, th->doff << 2))
1143 goto clear_hash;
1144 if (tcp_md5_hash_key(hp, key))
1145 goto clear_hash;
1146 ahash_request_set_crypt(req, NULL, md5_hash, 0);
1147 if (crypto_ahash_final(req))
1148 goto clear_hash;
1149
1150 tcp_put_md5sig_pool();
1151 return 0;
1152
1153clear_hash:
1154 tcp_put_md5sig_pool();
1155clear_hash_noput:
1156 memset(md5_hash, 0, 16);
1157 return 1;
1158}
1159
1160int tcp_v4_md5_hash_skb(char *md5_hash, const struct tcp_md5sig_key *key,
1161 const struct sock *sk,
1162 const struct sk_buff *skb)
1163{
1164 struct tcp_md5sig_pool *hp;
1165 struct ahash_request *req;
1166 const struct tcphdr *th = tcp_hdr(skb);
1167 __be32 saddr, daddr;
1168
1169 if (sk) { /* valid for establish/request sockets */
1170 saddr = sk->sk_rcv_saddr;
1171 daddr = sk->sk_daddr;
1172 } else {
1173 const struct iphdr *iph = ip_hdr(skb);
1174 saddr = iph->saddr;
1175 daddr = iph->daddr;
1176 }
1177
1178 hp = tcp_get_md5sig_pool();
1179 if (!hp)
1180 goto clear_hash_noput;
1181 req = hp->md5_req;
1182
1183 if (crypto_ahash_init(req))
1184 goto clear_hash;
1185
1186 if (tcp_v4_md5_hash_headers(hp, daddr, saddr, th, skb->len))
1187 goto clear_hash;
1188 if (tcp_md5_hash_skb_data(hp, skb, th->doff << 2))
1189 goto clear_hash;
1190 if (tcp_md5_hash_key(hp, key))
1191 goto clear_hash;
1192 ahash_request_set_crypt(req, NULL, md5_hash, 0);
1193 if (crypto_ahash_final(req))
1194 goto clear_hash;
1195
1196 tcp_put_md5sig_pool();
1197 return 0;
1198
1199clear_hash:
1200 tcp_put_md5sig_pool();
1201clear_hash_noput:
1202 memset(md5_hash, 0, 16);
1203 return 1;
1204}
1205EXPORT_SYMBOL(tcp_v4_md5_hash_skb);
1206
1207#endif
1208
1209/* Called with rcu_read_lock() */
1210static bool tcp_v4_inbound_md5_hash(const struct sock *sk,
1211 const struct sk_buff *skb)
1212{
1213#ifdef CONFIG_TCP_MD5SIG
1214 /*
1215 * This gets called for each TCP segment that arrives
1216 * so we want to be efficient.
1217 * We have 3 drop cases:
1218 * o No MD5 hash and one expected.
1219 * o MD5 hash and we're not expecting one.
1220 * o MD5 hash and its wrong.
1221 */
1222 const __u8 *hash_location = NULL;
1223 struct tcp_md5sig_key *hash_expected;
1224 const struct iphdr *iph = ip_hdr(skb);
1225 const struct tcphdr *th = tcp_hdr(skb);
1226 int genhash;
1227 unsigned char newhash[16];
1228
1229 hash_expected = tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&iph->saddr,
1230 AF_INET);
1231 hash_location = tcp_parse_md5sig_option(th);
1232
1233 /* We've parsed the options - do we have a hash? */
1234 if (!hash_expected && !hash_location)
1235 return false;
1236
1237 if (hash_expected && !hash_location) {
1238 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5NOTFOUND);
1239 return true;
1240 }
1241
1242 if (!hash_expected && hash_location) {
1243 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5UNEXPECTED);
1244 return true;
1245 }
1246
1247 /* Okay, so this is hash_expected and hash_location -
1248 * so we need to calculate the checksum.
1249 */
1250 genhash = tcp_v4_md5_hash_skb(newhash,
1251 hash_expected,
1252 NULL, skb);
1253
1254 if (genhash || memcmp(hash_location, newhash, 16) != 0) {
1255 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5FAILURE);
1256 net_info_ratelimited("MD5 Hash failed for (%pI4, %d)->(%pI4, %d)%s\n",
1257 &iph->saddr, ntohs(th->source),
1258 &iph->daddr, ntohs(th->dest),
1259 genhash ? " tcp_v4_calc_md5_hash failed"
1260 : "");
1261 return true;
1262 }
1263 return false;
1264#endif
1265 return false;
1266}
1267
1268static void tcp_v4_init_req(struct request_sock *req,
1269 const struct sock *sk_listener,
1270 struct sk_buff *skb)
1271{
1272 struct inet_request_sock *ireq = inet_rsk(req);
1273 struct net *net = sock_net(sk_listener);
1274
1275 sk_rcv_saddr_set(req_to_sk(req), ip_hdr(skb)->daddr);
1276 sk_daddr_set(req_to_sk(req), ip_hdr(skb)->saddr);
1277 RCU_INIT_POINTER(ireq->ireq_opt, tcp_v4_save_options(net, skb));
1278}
1279
1280static struct dst_entry *tcp_v4_route_req(const struct sock *sk,
1281 struct flowi *fl,
1282 const struct request_sock *req)
1283{
1284 return inet_csk_route_req(sk, &fl->u.ip4, req);
1285}
1286
1287struct request_sock_ops tcp_request_sock_ops __read_mostly = {
1288 .family = PF_INET,
1289 .obj_size = sizeof(struct tcp_request_sock),
1290 .rtx_syn_ack = tcp_rtx_synack,
1291 .send_ack = tcp_v4_reqsk_send_ack,
1292 .destructor = tcp_v4_reqsk_destructor,
1293 .send_reset = tcp_v4_send_reset,
1294 .syn_ack_timeout = tcp_syn_ack_timeout,
1295};
1296
1297static const struct tcp_request_sock_ops tcp_request_sock_ipv4_ops = {
1298 .mss_clamp = TCP_MSS_DEFAULT,
1299#ifdef CONFIG_TCP_MD5SIG
1300 .req_md5_lookup = tcp_v4_md5_lookup,
1301 .calc_md5_hash = tcp_v4_md5_hash_skb,
1302#endif
1303 .init_req = tcp_v4_init_req,
1304#ifdef CONFIG_SYN_COOKIES
1305 .cookie_init_seq = cookie_v4_init_sequence,
1306#endif
1307 .route_req = tcp_v4_route_req,
1308 .init_seq = tcp_v4_init_seq,
1309 .init_ts_off = tcp_v4_init_ts_off,
1310 .send_synack = tcp_v4_send_synack,
1311};
1312
1313int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
1314{
1315 /* Never answer to SYNs send to broadcast or multicast */
1316 if (skb_rtable(skb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
1317 goto drop;
1318
1319 return tcp_conn_request(&tcp_request_sock_ops,
1320 &tcp_request_sock_ipv4_ops, sk, skb);
1321
1322drop:
1323 tcp_listendrop(sk);
1324 return 0;
1325}
1326EXPORT_SYMBOL(tcp_v4_conn_request);
1327
1328
1329/*
1330 * The three way handshake has completed - we got a valid synack -
1331 * now create the new socket.
1332 */
1333struct sock *tcp_v4_syn_recv_sock(const struct sock *sk, struct sk_buff *skb,
1334 struct request_sock *req,
1335 struct dst_entry *dst,
1336 struct request_sock *req_unhash,
1337 bool *own_req)
1338{
1339 struct inet_request_sock *ireq;
1340 struct inet_sock *newinet;
1341 struct tcp_sock *newtp;
1342 struct sock *newsk;
1343#ifdef CONFIG_TCP_MD5SIG
1344 struct tcp_md5sig_key *key;
1345#endif
1346 struct ip_options_rcu *inet_opt;
1347
1348 if (sk_acceptq_is_full(sk))
1349 goto exit_overflow;
1350
1351 newsk = tcp_create_openreq_child(sk, req, skb);
1352 if (!newsk)
1353 goto exit_nonewsk;
1354
1355 newsk->sk_gso_type = SKB_GSO_TCPV4;
1356 inet_sk_rx_dst_set(newsk, skb);
1357
1358 newtp = tcp_sk(newsk);
1359 newinet = inet_sk(newsk);
1360 ireq = inet_rsk(req);
1361 sk_daddr_set(newsk, ireq->ir_rmt_addr);
1362 sk_rcv_saddr_set(newsk, ireq->ir_loc_addr);
1363 newsk->sk_bound_dev_if = ireq->ir_iif;
1364 newinet->inet_saddr = ireq->ir_loc_addr;
1365 inet_opt = rcu_dereference(ireq->ireq_opt);
1366 RCU_INIT_POINTER(newinet->inet_opt, inet_opt);
1367 newinet->mc_index = inet_iif(skb);
1368 newinet->mc_ttl = ip_hdr(skb)->ttl;
1369 newinet->rcv_tos = ip_hdr(skb)->tos;
1370 inet_csk(newsk)->icsk_ext_hdr_len = 0;
1371 if (inet_opt)
1372 inet_csk(newsk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
1373 newinet->inet_id = newtp->write_seq ^ jiffies;
1374
1375 if (!dst) {
1376 dst = inet_csk_route_child_sock(sk, newsk, req);
1377 if (!dst)
1378 goto put_and_exit;
1379 } else {
1380 /* syncookie case : see end of cookie_v4_check() */
1381 }
1382 sk_setup_caps(newsk, dst);
1383
1384 tcp_ca_openreq_child(newsk, dst);
1385
1386 tcp_sync_mss(newsk, dst_mtu(dst));
1387 newtp->advmss = tcp_mss_clamp(tcp_sk(sk), dst_metric_advmss(dst));
1388
1389 tcp_initialize_rcv_mss(newsk);
1390
1391#ifdef CONFIG_TCP_MD5SIG
1392 /* Copy over the MD5 key from the original socket */
1393 key = tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&newinet->inet_daddr,
1394 AF_INET);
1395 if (key) {
1396 /*
1397 * We're using one, so create a matching key
1398 * on the newsk structure. If we fail to get
1399 * memory, then we end up not copying the key
1400 * across. Shucks.
1401 */
1402 tcp_md5_do_add(newsk, (union tcp_md5_addr *)&newinet->inet_daddr,
1403 AF_INET, 32, key->key, key->keylen, GFP_ATOMIC);
1404 sk_nocaps_add(newsk, NETIF_F_GSO_MASK);
1405 }
1406#endif
1407
1408 if (__inet_inherit_port(sk, newsk) < 0)
1409 goto put_and_exit;
1410 *own_req = inet_ehash_nolisten(newsk, req_to_sk(req_unhash));
1411 if (likely(*own_req)) {
1412 tcp_move_syn(newtp, req);
1413 ireq->ireq_opt = NULL;
1414 } else {
1415 newinet->inet_opt = NULL;
1416 }
1417 return newsk;
1418
1419exit_overflow:
1420 NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
1421exit_nonewsk:
1422 dst_release(dst);
1423exit:
1424 tcp_listendrop(sk);
1425 return NULL;
1426put_and_exit:
1427 newinet->inet_opt = NULL;
1428 inet_csk_prepare_forced_close(newsk);
1429 tcp_done(newsk);
1430 goto exit;
1431}
1432EXPORT_SYMBOL(tcp_v4_syn_recv_sock);
1433
1434static struct sock *tcp_v4_cookie_check(struct sock *sk, struct sk_buff *skb)
1435{
1436#ifdef CONFIG_SYN_COOKIES
1437 const struct tcphdr *th = tcp_hdr(skb);
1438
1439 if (!th->syn)
1440 sk = cookie_v4_check(sk, skb);
1441#endif
1442 return sk;
1443}
1444
1445/* The socket must have it's spinlock held when we get
1446 * here, unless it is a TCP_LISTEN socket.
1447 *
1448 * We have a potential double-lock case here, so even when
1449 * doing backlog processing we use the BH locking scheme.
1450 * This is because we cannot sleep with the original spinlock
1451 * held.
1452 */
1453int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
1454{
1455 struct sock *rsk;
1456
1457 if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
1458 struct dst_entry *dst = sk->sk_rx_dst;
1459
1460 sock_rps_save_rxhash(sk, skb);
1461 sk_mark_napi_id(sk, skb);
1462 if (dst) {
1463 if (inet_sk(sk)->rx_dst_ifindex != skb->skb_iif ||
1464 !dst->ops->check(dst, 0)) {
1465 dst_release(dst);
1466 sk->sk_rx_dst = NULL;
1467 }
1468 }
1469 tcp_rcv_established(sk, skb, tcp_hdr(skb));
1470 return 0;
1471 }
1472
1473 if (tcp_checksum_complete(skb))
1474 goto csum_err;
1475
1476 if (sk->sk_state == TCP_LISTEN) {
1477 struct sock *nsk = tcp_v4_cookie_check(sk, skb);
1478
1479 if (!nsk)
1480 goto discard;
1481 if (nsk != sk) {
1482 if (tcp_child_process(sk, nsk, skb)) {
1483 rsk = nsk;
1484 goto reset;
1485 }
1486 return 0;
1487 }
1488 } else
1489 sock_rps_save_rxhash(sk, skb);
1490
1491 if (tcp_rcv_state_process(sk, skb)) {
1492 rsk = sk;
1493 goto reset;
1494 }
1495 return 0;
1496
1497reset:
1498 tcp_v4_send_reset(rsk, skb);
1499discard:
1500 kfree_skb(skb);
1501 /* Be careful here. If this function gets more complicated and
1502 * gcc suffers from register pressure on the x86, sk (in %ebx)
1503 * might be destroyed here. This current version compiles correctly,
1504 * but you have been warned.
1505 */
1506 return 0;
1507
1508csum_err:
1509 TCP_INC_STATS(sock_net(sk), TCP_MIB_CSUMERRORS);
1510 TCP_INC_STATS(sock_net(sk), TCP_MIB_INERRS);
1511 goto discard;
1512}
1513EXPORT_SYMBOL(tcp_v4_do_rcv);
1514
1515int tcp_v4_early_demux(struct sk_buff *skb)
1516{
1517 const struct iphdr *iph;
1518 const struct tcphdr *th;
1519 struct sock *sk;
1520
1521 if (skb->pkt_type != PACKET_HOST)
1522 return 0;
1523
1524 if (!pskb_may_pull(skb, skb_transport_offset(skb) + sizeof(struct tcphdr)))
1525 return 0;
1526
1527 iph = ip_hdr(skb);
1528 th = tcp_hdr(skb);
1529
1530 if (th->doff < sizeof(struct tcphdr) / 4)
1531 return 0;
1532
1533 sk = __inet_lookup_established(dev_net(skb->dev), &tcp_hashinfo,
1534 iph->saddr, th->source,
1535 iph->daddr, ntohs(th->dest),
1536 skb->skb_iif, inet_sdif(skb));
1537 if (sk) {
1538 skb->sk = sk;
1539 skb->destructor = sock_edemux;
1540 if (sk_fullsock(sk)) {
1541 struct dst_entry *dst = READ_ONCE(sk->sk_rx_dst);
1542
1543 if (dst)
1544 dst = dst_check(dst, 0);
1545 if (dst &&
1546 inet_sk(sk)->rx_dst_ifindex == skb->skb_iif)
1547 skb_dst_set_noref(skb, dst);
1548 }
1549 }
1550 return 0;
1551}
1552
1553bool tcp_add_backlog(struct sock *sk, struct sk_buff *skb)
1554{
1555 u32 limit = sk->sk_rcvbuf + sk->sk_sndbuf;
1556
1557 /* Only socket owner can try to collapse/prune rx queues
1558 * to reduce memory overhead, so add a little headroom here.
1559 * Few sockets backlog are possibly concurrently non empty.
1560 */
1561 limit += 64*1024;
1562
1563 /* In case all data was pulled from skb frags (in __pskb_pull_tail()),
1564 * we can fix skb->truesize to its real value to avoid future drops.
1565 * This is valid because skb is not yet charged to the socket.
1566 * It has been noticed pure SACK packets were sometimes dropped
1567 * (if cooked by drivers without copybreak feature).
1568 */
1569 skb_condense(skb);
1570
1571 if (unlikely(sk_add_backlog(sk, skb, limit))) {
1572 bh_unlock_sock(sk);
1573 __NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPBACKLOGDROP);
1574 return true;
1575 }
1576 return false;
1577}
1578EXPORT_SYMBOL(tcp_add_backlog);
1579
1580int tcp_filter(struct sock *sk, struct sk_buff *skb)
1581{
1582 struct tcphdr *th = (struct tcphdr *)skb->data;
1583 unsigned int eaten = skb->len;
1584 int err;
1585
1586 err = sk_filter_trim_cap(sk, skb, th->doff * 4);
1587 if (!err) {
1588 eaten -= skb->len;
1589 TCP_SKB_CB(skb)->end_seq -= eaten;
1590 }
1591 return err;
1592}
1593EXPORT_SYMBOL(tcp_filter);
1594
1595static void tcp_v4_restore_cb(struct sk_buff *skb)
1596{
1597 memmove(IPCB(skb), &TCP_SKB_CB(skb)->header.h4,
1598 sizeof(struct inet_skb_parm));
1599}
1600
1601static void tcp_v4_fill_cb(struct sk_buff *skb, const struct iphdr *iph,
1602 const struct tcphdr *th)
1603{
1604 /* This is tricky : We move IPCB at its correct location into TCP_SKB_CB()
1605 * barrier() makes sure compiler wont play fool^Waliasing games.
1606 */
1607 memmove(&TCP_SKB_CB(skb)->header.h4, IPCB(skb),
1608 sizeof(struct inet_skb_parm));
1609 barrier();
1610
1611 TCP_SKB_CB(skb)->seq = ntohl(th->seq);
1612 TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
1613 skb->len - th->doff * 4);
1614 TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
1615 TCP_SKB_CB(skb)->tcp_flags = tcp_flag_byte(th);
1616 TCP_SKB_CB(skb)->tcp_tw_isn = 0;
1617 TCP_SKB_CB(skb)->ip_dsfield = ipv4_get_dsfield(iph);
1618 TCP_SKB_CB(skb)->sacked = 0;
1619 TCP_SKB_CB(skb)->has_rxtstamp =
1620 skb->tstamp || skb_hwtstamps(skb)->hwtstamp;
1621}
1622
1623/*
1624 * From tcp_input.c
1625 */
1626
1627int tcp_v4_rcv(struct sk_buff *skb)
1628{
1629 struct net *net = dev_net(skb->dev);
1630 int sdif = inet_sdif(skb);
1631 const struct iphdr *iph;
1632 const struct tcphdr *th;
1633 bool refcounted;
1634 struct sock *sk;
1635 int ret;
1636
1637 if (skb->pkt_type != PACKET_HOST)
1638 goto discard_it;
1639
1640 /* Count it even if it's bad */
1641 __TCP_INC_STATS(net, TCP_MIB_INSEGS);
1642
1643 if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
1644 goto discard_it;
1645
1646 th = (const struct tcphdr *)skb->data;
1647
1648 if (unlikely(th->doff < sizeof(struct tcphdr) / 4))
1649 goto bad_packet;
1650 if (!pskb_may_pull(skb, th->doff * 4))
1651 goto discard_it;
1652
1653 /* An explanation is required here, I think.
1654 * Packet length and doff are validated by header prediction,
1655 * provided case of th->doff==0 is eliminated.
1656 * So, we defer the checks. */
1657
1658 if (skb_checksum_init(skb, IPPROTO_TCP, inet_compute_pseudo))
1659 goto csum_error;
1660
1661 th = (const struct tcphdr *)skb->data;
1662 iph = ip_hdr(skb);
1663lookup:
1664 sk = __inet_lookup_skb(&tcp_hashinfo, skb, __tcp_hdrlen(th), th->source,
1665 th->dest, sdif, &refcounted);
1666 if (!sk)
1667 goto no_tcp_socket;
1668
1669process:
1670 if (sk->sk_state == TCP_TIME_WAIT)
1671 goto do_time_wait;
1672
1673 if (sk->sk_state == TCP_NEW_SYN_RECV) {
1674 struct request_sock *req = inet_reqsk(sk);
1675 struct sock *nsk;
1676
1677 sk = req->rsk_listener;
1678 if (unlikely(tcp_v4_inbound_md5_hash(sk, skb))) {
1679 sk_drops_add(sk, skb);
1680 reqsk_put(req);
1681 goto discard_it;
1682 }
1683 if (unlikely(sk->sk_state != TCP_LISTEN)) {
1684 inet_csk_reqsk_queue_drop_and_put(sk, req);
1685 goto lookup;
1686 }
1687 /* We own a reference on the listener, increase it again
1688 * as we might lose it too soon.
1689 */
1690 sock_hold(sk);
1691 refcounted = true;
1692 nsk = NULL;
1693 if (!tcp_filter(sk, skb)) {
1694 th = (const struct tcphdr *)skb->data;
1695 iph = ip_hdr(skb);
1696 tcp_v4_fill_cb(skb, iph, th);
1697 nsk = tcp_check_req(sk, skb, req, false);
1698 }
1699 if (!nsk) {
1700 reqsk_put(req);
1701 goto discard_and_relse;
1702 }
1703 if (nsk == sk) {
1704 reqsk_put(req);
1705 tcp_v4_restore_cb(skb);
1706 } else if (tcp_child_process(sk, nsk, skb)) {
1707 tcp_v4_send_reset(nsk, skb);
1708 goto discard_and_relse;
1709 } else {
1710 sock_put(sk);
1711 return 0;
1712 }
1713 }
1714 if (unlikely(iph->ttl < inet_sk(sk)->min_ttl)) {
1715 __NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP);
1716 goto discard_and_relse;
1717 }
1718
1719 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
1720 goto discard_and_relse;
1721
1722 if (tcp_v4_inbound_md5_hash(sk, skb))
1723 goto discard_and_relse;
1724
1725 nf_reset(skb);
1726
1727 if (tcp_filter(sk, skb))
1728 goto discard_and_relse;
1729 th = (const struct tcphdr *)skb->data;
1730 iph = ip_hdr(skb);
1731 tcp_v4_fill_cb(skb, iph, th);
1732
1733 skb->dev = NULL;
1734
1735 if (sk->sk_state == TCP_LISTEN) {
1736 ret = tcp_v4_do_rcv(sk, skb);
1737 goto put_and_return;
1738 }
1739
1740 sk_incoming_cpu_update(sk);
1741
1742 bh_lock_sock_nested(sk);
1743 tcp_segs_in(tcp_sk(sk), skb);
1744 ret = 0;
1745 if (!sock_owned_by_user(sk)) {
1746 ret = tcp_v4_do_rcv(sk, skb);
1747 } else if (tcp_add_backlog(sk, skb)) {
1748 goto discard_and_relse;
1749 }
1750 bh_unlock_sock(sk);
1751
1752put_and_return:
1753 if (refcounted)
1754 sock_put(sk);
1755
1756 return ret;
1757
1758no_tcp_socket:
1759 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
1760 goto discard_it;
1761
1762 tcp_v4_fill_cb(skb, iph, th);
1763
1764 if (tcp_checksum_complete(skb)) {
1765csum_error:
1766 __TCP_INC_STATS(net, TCP_MIB_CSUMERRORS);
1767bad_packet:
1768 __TCP_INC_STATS(net, TCP_MIB_INERRS);
1769 } else {
1770 tcp_v4_send_reset(NULL, skb);
1771 }
1772
1773discard_it:
1774 /* Discard frame. */
1775 kfree_skb(skb);
1776 return 0;
1777
1778discard_and_relse:
1779 sk_drops_add(sk, skb);
1780 if (refcounted)
1781 sock_put(sk);
1782 goto discard_it;
1783
1784do_time_wait:
1785 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
1786 inet_twsk_put(inet_twsk(sk));
1787 goto discard_it;
1788 }
1789
1790 tcp_v4_fill_cb(skb, iph, th);
1791
1792 if (tcp_checksum_complete(skb)) {
1793 inet_twsk_put(inet_twsk(sk));
1794 goto csum_error;
1795 }
1796 switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) {
1797 case TCP_TW_SYN: {
1798 struct sock *sk2 = inet_lookup_listener(dev_net(skb->dev),
1799 &tcp_hashinfo, skb,
1800 __tcp_hdrlen(th),
1801 iph->saddr, th->source,
1802 iph->daddr, th->dest,
1803 inet_iif(skb),
1804 sdif);
1805 if (sk2) {
1806 inet_twsk_deschedule_put(inet_twsk(sk));
1807 sk = sk2;
1808 tcp_v4_restore_cb(skb);
1809 refcounted = false;
1810 goto process;
1811 }
1812 }
1813 /* to ACK */
1814 /* fall through */
1815 case TCP_TW_ACK:
1816 tcp_v4_timewait_ack(sk, skb);
1817 break;
1818 case TCP_TW_RST:
1819 tcp_v4_send_reset(sk, skb);
1820 inet_twsk_deschedule_put(inet_twsk(sk));
1821 goto discard_it;
1822 case TCP_TW_SUCCESS:;
1823 }
1824 goto discard_it;
1825}
1826
1827static struct timewait_sock_ops tcp_timewait_sock_ops = {
1828 .twsk_obj_size = sizeof(struct tcp_timewait_sock),
1829 .twsk_unique = tcp_twsk_unique,
1830 .twsk_destructor= tcp_twsk_destructor,
1831};
1832
1833void inet_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb)
1834{
1835 struct dst_entry *dst = skb_dst(skb);
1836
1837 if (dst && dst_hold_safe(dst)) {
1838 sk->sk_rx_dst = dst;
1839 inet_sk(sk)->rx_dst_ifindex = skb->skb_iif;
1840 }
1841}
1842EXPORT_SYMBOL(inet_sk_rx_dst_set);
1843
1844const struct inet_connection_sock_af_ops ipv4_specific = {
1845 .queue_xmit = ip_queue_xmit,
1846 .send_check = tcp_v4_send_check,
1847 .rebuild_header = inet_sk_rebuild_header,
1848 .sk_rx_dst_set = inet_sk_rx_dst_set,
1849 .conn_request = tcp_v4_conn_request,
1850 .syn_recv_sock = tcp_v4_syn_recv_sock,
1851 .net_header_len = sizeof(struct iphdr),
1852 .setsockopt = ip_setsockopt,
1853 .getsockopt = ip_getsockopt,
1854 .addr2sockaddr = inet_csk_addr2sockaddr,
1855 .sockaddr_len = sizeof(struct sockaddr_in),
1856#ifdef CONFIG_COMPAT
1857 .compat_setsockopt = compat_ip_setsockopt,
1858 .compat_getsockopt = compat_ip_getsockopt,
1859#endif
1860 .mtu_reduced = tcp_v4_mtu_reduced,
1861};
1862EXPORT_SYMBOL(ipv4_specific);
1863
1864#ifdef CONFIG_TCP_MD5SIG
1865static const struct tcp_sock_af_ops tcp_sock_ipv4_specific = {
1866 .md5_lookup = tcp_v4_md5_lookup,
1867 .calc_md5_hash = tcp_v4_md5_hash_skb,
1868 .md5_parse = tcp_v4_parse_md5_keys,
1869};
1870#endif
1871
1872/* NOTE: A lot of things set to zero explicitly by call to
1873 * sk_alloc() so need not be done here.
1874 */
1875static int tcp_v4_init_sock(struct sock *sk)
1876{
1877 struct inet_connection_sock *icsk = inet_csk(sk);
1878
1879 tcp_init_sock(sk);
1880
1881 icsk->icsk_af_ops = &ipv4_specific;
1882
1883#ifdef CONFIG_TCP_MD5SIG
1884 tcp_sk(sk)->af_specific = &tcp_sock_ipv4_specific;
1885#endif
1886
1887 return 0;
1888}
1889
1890void tcp_v4_destroy_sock(struct sock *sk)
1891{
1892 struct tcp_sock *tp = tcp_sk(sk);
1893
1894 trace_tcp_destroy_sock(sk);
1895
1896 tcp_clear_xmit_timers(sk);
1897
1898 tcp_cleanup_congestion_control(sk);
1899
1900 tcp_cleanup_ulp(sk);
1901
1902 /* Cleanup up the write buffer. */
1903 tcp_write_queue_purge(sk);
1904
1905 /* Check if we want to disable active TFO */
1906 tcp_fastopen_active_disable_ofo_check(sk);
1907
1908 /* Cleans up our, hopefully empty, out_of_order_queue. */
1909 skb_rbtree_purge(&tp->out_of_order_queue);
1910
1911#ifdef CONFIG_TCP_MD5SIG
1912 /* Clean up the MD5 key list, if any */
1913 if (tp->md5sig_info) {
1914 tcp_clear_md5_list(sk);
1915 kfree_rcu(rcu_dereference_protected(tp->md5sig_info, 1), rcu);
1916 tp->md5sig_info = NULL;
1917 }
1918#endif
1919
1920 /* Clean up a referenced TCP bind bucket. */
1921 if (inet_csk(sk)->icsk_bind_hash)
1922 inet_put_port(sk);
1923
1924 BUG_ON(tp->fastopen_rsk);
1925
1926 /* If socket is aborted during connect operation */
1927 tcp_free_fastopen_req(tp);
1928 tcp_fastopen_destroy_cipher(sk);
1929 tcp_saved_syn_free(tp);
1930
1931 sk_sockets_allocated_dec(sk);
1932}
1933EXPORT_SYMBOL(tcp_v4_destroy_sock);
1934
1935#ifdef CONFIG_PROC_FS
1936/* Proc filesystem TCP sock list dumping. */
1937
1938/*
1939 * Get next listener socket follow cur. If cur is NULL, get first socket
1940 * starting from bucket given in st->bucket; when st->bucket is zero the
1941 * very first socket in the hash table is returned.
1942 */
1943static void *listening_get_next(struct seq_file *seq, void *cur)
1944{
1945 struct tcp_iter_state *st = seq->private;
1946 struct net *net = seq_file_net(seq);
1947 struct inet_listen_hashbucket *ilb;
1948 struct sock *sk = cur;
1949
1950 if (!sk) {
1951get_head:
1952 ilb = &tcp_hashinfo.listening_hash[st->bucket];
1953 spin_lock(&ilb->lock);
1954 sk = sk_head(&ilb->head);
1955 st->offset = 0;
1956 goto get_sk;
1957 }
1958 ilb = &tcp_hashinfo.listening_hash[st->bucket];
1959 ++st->num;
1960 ++st->offset;
1961
1962 sk = sk_next(sk);
1963get_sk:
1964 sk_for_each_from(sk) {
1965 if (!net_eq(sock_net(sk), net))
1966 continue;
1967 if (sk->sk_family == st->family)
1968 return sk;
1969 }
1970 spin_unlock(&ilb->lock);
1971 st->offset = 0;
1972 if (++st->bucket < INET_LHTABLE_SIZE)
1973 goto get_head;
1974 return NULL;
1975}
1976
1977static void *listening_get_idx(struct seq_file *seq, loff_t *pos)
1978{
1979 struct tcp_iter_state *st = seq->private;
1980 void *rc;
1981
1982 st->bucket = 0;
1983 st->offset = 0;
1984 rc = listening_get_next(seq, NULL);
1985
1986 while (rc && *pos) {
1987 rc = listening_get_next(seq, rc);
1988 --*pos;
1989 }
1990 return rc;
1991}
1992
1993static inline bool empty_bucket(const struct tcp_iter_state *st)
1994{
1995 return hlist_nulls_empty(&tcp_hashinfo.ehash[st->bucket].chain);
1996}
1997
1998/*
1999 * Get first established socket starting from bucket given in st->bucket.
2000 * If st->bucket is zero, the very first socket in the hash is returned.
2001 */
2002static void *established_get_first(struct seq_file *seq)
2003{
2004 struct tcp_iter_state *st = seq->private;
2005 struct net *net = seq_file_net(seq);
2006 void *rc = NULL;
2007
2008 st->offset = 0;
2009 for (; st->bucket <= tcp_hashinfo.ehash_mask; ++st->bucket) {
2010 struct sock *sk;
2011 struct hlist_nulls_node *node;
2012 spinlock_t *lock = inet_ehash_lockp(&tcp_hashinfo, st->bucket);
2013
2014 /* Lockless fast path for the common case of empty buckets */
2015 if (empty_bucket(st))
2016 continue;
2017
2018 spin_lock_bh(lock);
2019 sk_nulls_for_each(sk, node, &tcp_hashinfo.ehash[st->bucket].chain) {
2020 if (sk->sk_family != st->family ||
2021 !net_eq(sock_net(sk), net)) {
2022 continue;
2023 }
2024 rc = sk;
2025 goto out;
2026 }
2027 spin_unlock_bh(lock);
2028 }
2029out:
2030 return rc;
2031}
2032
2033static void *established_get_next(struct seq_file *seq, void *cur)
2034{
2035 struct sock *sk = cur;
2036 struct hlist_nulls_node *node;
2037 struct tcp_iter_state *st = seq->private;
2038 struct net *net = seq_file_net(seq);
2039
2040 ++st->num;
2041 ++st->offset;
2042
2043 sk = sk_nulls_next(sk);
2044
2045 sk_nulls_for_each_from(sk, node) {
2046 if (sk->sk_family == st->family && net_eq(sock_net(sk), net))
2047 return sk;
2048 }
2049
2050 spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
2051 ++st->bucket;
2052 return established_get_first(seq);
2053}
2054
2055static void *established_get_idx(struct seq_file *seq, loff_t pos)
2056{
2057 struct tcp_iter_state *st = seq->private;
2058 void *rc;
2059
2060 st->bucket = 0;
2061 rc = established_get_first(seq);
2062
2063 while (rc && pos) {
2064 rc = established_get_next(seq, rc);
2065 --pos;
2066 }
2067 return rc;
2068}
2069
2070static void *tcp_get_idx(struct seq_file *seq, loff_t pos)
2071{
2072 void *rc;
2073 struct tcp_iter_state *st = seq->private;
2074
2075 st->state = TCP_SEQ_STATE_LISTENING;
2076 rc = listening_get_idx(seq, &pos);
2077
2078 if (!rc) {
2079 st->state = TCP_SEQ_STATE_ESTABLISHED;
2080 rc = established_get_idx(seq, pos);
2081 }
2082
2083 return rc;
2084}
2085
2086static void *tcp_seek_last_pos(struct seq_file *seq)
2087{
2088 struct tcp_iter_state *st = seq->private;
2089 int offset = st->offset;
2090 int orig_num = st->num;
2091 void *rc = NULL;
2092
2093 switch (st->state) {
2094 case TCP_SEQ_STATE_LISTENING:
2095 if (st->bucket >= INET_LHTABLE_SIZE)
2096 break;
2097 st->state = TCP_SEQ_STATE_LISTENING;
2098 rc = listening_get_next(seq, NULL);
2099 while (offset-- && rc)
2100 rc = listening_get_next(seq, rc);
2101 if (rc)
2102 break;
2103 st->bucket = 0;
2104 st->state = TCP_SEQ_STATE_ESTABLISHED;
2105 /* Fallthrough */
2106 case TCP_SEQ_STATE_ESTABLISHED:
2107 if (st->bucket > tcp_hashinfo.ehash_mask)
2108 break;
2109 rc = established_get_first(seq);
2110 while (offset-- && rc)
2111 rc = established_get_next(seq, rc);
2112 }
2113
2114 st->num = orig_num;
2115
2116 return rc;
2117}
2118
2119static void *tcp_seq_start(struct seq_file *seq, loff_t *pos)
2120{
2121 struct tcp_iter_state *st = seq->private;
2122 void *rc;
2123
2124 if (*pos && *pos == st->last_pos) {
2125 rc = tcp_seek_last_pos(seq);
2126 if (rc)
2127 goto out;
2128 }
2129
2130 st->state = TCP_SEQ_STATE_LISTENING;
2131 st->num = 0;
2132 st->bucket = 0;
2133 st->offset = 0;
2134 rc = *pos ? tcp_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
2135
2136out:
2137 st->last_pos = *pos;
2138 return rc;
2139}
2140
2141static void *tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2142{
2143 struct tcp_iter_state *st = seq->private;
2144 void *rc = NULL;
2145
2146 if (v == SEQ_START_TOKEN) {
2147 rc = tcp_get_idx(seq, 0);
2148 goto out;
2149 }
2150
2151 switch (st->state) {
2152 case TCP_SEQ_STATE_LISTENING:
2153 rc = listening_get_next(seq, v);
2154 if (!rc) {
2155 st->state = TCP_SEQ_STATE_ESTABLISHED;
2156 st->bucket = 0;
2157 st->offset = 0;
2158 rc = established_get_first(seq);
2159 }
2160 break;
2161 case TCP_SEQ_STATE_ESTABLISHED:
2162 rc = established_get_next(seq, v);
2163 break;
2164 }
2165out:
2166 ++*pos;
2167 st->last_pos = *pos;
2168 return rc;
2169}
2170
2171static void tcp_seq_stop(struct seq_file *seq, void *v)
2172{
2173 struct tcp_iter_state *st = seq->private;
2174
2175 switch (st->state) {
2176 case TCP_SEQ_STATE_LISTENING:
2177 if (v != SEQ_START_TOKEN)
2178 spin_unlock(&tcp_hashinfo.listening_hash[st->bucket].lock);
2179 break;
2180 case TCP_SEQ_STATE_ESTABLISHED:
2181 if (v)
2182 spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
2183 break;
2184 }
2185}
2186
2187int tcp_seq_open(struct inode *inode, struct file *file)
2188{
2189 struct tcp_seq_afinfo *afinfo = PDE_DATA(inode);
2190 struct tcp_iter_state *s;
2191 int err;
2192
2193 err = seq_open_net(inode, file, &afinfo->seq_ops,
2194 sizeof(struct tcp_iter_state));
2195 if (err < 0)
2196 return err;
2197
2198 s = ((struct seq_file *)file->private_data)->private;
2199 s->family = afinfo->family;
2200 s->last_pos = 0;
2201 return 0;
2202}
2203EXPORT_SYMBOL(tcp_seq_open);
2204
2205int tcp_proc_register(struct net *net, struct tcp_seq_afinfo *afinfo)
2206{
2207 int rc = 0;
2208 struct proc_dir_entry *p;
2209
2210 afinfo->seq_ops.start = tcp_seq_start;
2211 afinfo->seq_ops.next = tcp_seq_next;
2212 afinfo->seq_ops.stop = tcp_seq_stop;
2213
2214 p = proc_create_data(afinfo->name, S_IRUGO, net->proc_net,
2215 afinfo->seq_fops, afinfo);
2216 if (!p)
2217 rc = -ENOMEM;
2218 return rc;
2219}
2220EXPORT_SYMBOL(tcp_proc_register);
2221
2222void tcp_proc_unregister(struct net *net, struct tcp_seq_afinfo *afinfo)
2223{
2224 remove_proc_entry(afinfo->name, net->proc_net);
2225}
2226EXPORT_SYMBOL(tcp_proc_unregister);
2227
2228static void get_openreq4(const struct request_sock *req,
2229 struct seq_file *f, int i)
2230{
2231 const struct inet_request_sock *ireq = inet_rsk(req);
2232 long delta = req->rsk_timer.expires - jiffies;
2233
2234 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2235 " %02X %08X:%08X %02X:%08lX %08X %5u %8d %u %d %pK",
2236 i,
2237 ireq->ir_loc_addr,
2238 ireq->ir_num,
2239 ireq->ir_rmt_addr,
2240 ntohs(ireq->ir_rmt_port),
2241 TCP_SYN_RECV,
2242 0, 0, /* could print option size, but that is af dependent. */
2243 1, /* timers active (only the expire timer) */
2244 jiffies_delta_to_clock_t(delta),
2245 req->num_timeout,
2246 from_kuid_munged(seq_user_ns(f),
2247 sock_i_uid(req->rsk_listener)),
2248 0, /* non standard timer */
2249 0, /* open_requests have no inode */
2250 0,
2251 req);
2252}
2253
2254static void get_tcp4_sock(struct sock *sk, struct seq_file *f, int i)
2255{
2256 int timer_active;
2257 unsigned long timer_expires;
2258 const struct tcp_sock *tp = tcp_sk(sk);
2259 const struct inet_connection_sock *icsk = inet_csk(sk);
2260 const struct inet_sock *inet = inet_sk(sk);
2261 const struct fastopen_queue *fastopenq = &icsk->icsk_accept_queue.fastopenq;
2262 __be32 dest = inet->inet_daddr;
2263 __be32 src = inet->inet_rcv_saddr;
2264 __u16 destp = ntohs(inet->inet_dport);
2265 __u16 srcp = ntohs(inet->inet_sport);
2266 int rx_queue;
2267 int state;
2268
2269 if (icsk->icsk_pending == ICSK_TIME_RETRANS ||
2270 icsk->icsk_pending == ICSK_TIME_REO_TIMEOUT ||
2271 icsk->icsk_pending == ICSK_TIME_LOSS_PROBE) {
2272 timer_active = 1;
2273 timer_expires = icsk->icsk_timeout;
2274 } else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
2275 timer_active = 4;
2276 timer_expires = icsk->icsk_timeout;
2277 } else if (timer_pending(&sk->sk_timer)) {
2278 timer_active = 2;
2279 timer_expires = sk->sk_timer.expires;
2280 } else {
2281 timer_active = 0;
2282 timer_expires = jiffies;
2283 }
2284
2285 state = inet_sk_state_load(sk);
2286 if (state == TCP_LISTEN)
2287 rx_queue = sk->sk_ack_backlog;
2288 else
2289 /* Because we don't lock the socket,
2290 * we might find a transient negative value.
2291 */
2292 rx_queue = max_t(int, tp->rcv_nxt - tp->copied_seq, 0);
2293
2294 seq_printf(f, "%4d: %08X:%04X %08X:%04X %02X %08X:%08X %02X:%08lX "
2295 "%08X %5u %8d %lu %d %pK %lu %lu %u %u %d",
2296 i, src, srcp, dest, destp, state,
2297 tp->write_seq - tp->snd_una,
2298 rx_queue,
2299 timer_active,
2300 jiffies_delta_to_clock_t(timer_expires - jiffies),
2301 icsk->icsk_retransmits,
2302 from_kuid_munged(seq_user_ns(f), sock_i_uid(sk)),
2303 icsk->icsk_probes_out,
2304 sock_i_ino(sk),
2305 refcount_read(&sk->sk_refcnt), sk,
2306 jiffies_to_clock_t(icsk->icsk_rto),
2307 jiffies_to_clock_t(icsk->icsk_ack.ato),
2308 (icsk->icsk_ack.quick << 1) | icsk->icsk_ack.pingpong,
2309 tp->snd_cwnd,
2310 state == TCP_LISTEN ?
2311 fastopenq->max_qlen :
2312 (tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh));
2313}
2314
2315static void get_timewait4_sock(const struct inet_timewait_sock *tw,
2316 struct seq_file *f, int i)
2317{
2318 long delta = tw->tw_timer.expires - jiffies;
2319 __be32 dest, src;
2320 __u16 destp, srcp;
2321
2322 dest = tw->tw_daddr;
2323 src = tw->tw_rcv_saddr;
2324 destp = ntohs(tw->tw_dport);
2325 srcp = ntohs(tw->tw_sport);
2326
2327 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2328 " %02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK",
2329 i, src, srcp, dest, destp, tw->tw_substate, 0, 0,
2330 3, jiffies_delta_to_clock_t(delta), 0, 0, 0, 0,
2331 refcount_read(&tw->tw_refcnt), tw);
2332}
2333
2334#define TMPSZ 150
2335
2336static int tcp4_seq_show(struct seq_file *seq, void *v)
2337{
2338 struct tcp_iter_state *st;
2339 struct sock *sk = v;
2340
2341 seq_setwidth(seq, TMPSZ - 1);
2342 if (v == SEQ_START_TOKEN) {
2343 seq_puts(seq, " sl local_address rem_address st tx_queue "
2344 "rx_queue tr tm->when retrnsmt uid timeout "
2345 "inode");
2346 goto out;
2347 }
2348 st = seq->private;
2349
2350 if (sk->sk_state == TCP_TIME_WAIT)
2351 get_timewait4_sock(v, seq, st->num);
2352 else if (sk->sk_state == TCP_NEW_SYN_RECV)
2353 get_openreq4(v, seq, st->num);
2354 else
2355 get_tcp4_sock(v, seq, st->num);
2356out:
2357 seq_pad(seq, '\n');
2358 return 0;
2359}
2360
2361static const struct file_operations tcp_afinfo_seq_fops = {
2362 .open = tcp_seq_open,
2363 .read = seq_read,
2364 .llseek = seq_lseek,
2365 .release = seq_release_net
2366};
2367
2368static struct tcp_seq_afinfo tcp4_seq_afinfo = {
2369 .name = "tcp",
2370 .family = AF_INET,
2371 .seq_fops = &tcp_afinfo_seq_fops,
2372 .seq_ops = {
2373 .show = tcp4_seq_show,
2374 },
2375};
2376
2377static int __net_init tcp4_proc_init_net(struct net *net)
2378{
2379 return tcp_proc_register(net, &tcp4_seq_afinfo);
2380}
2381
2382static void __net_exit tcp4_proc_exit_net(struct net *net)
2383{
2384 tcp_proc_unregister(net, &tcp4_seq_afinfo);
2385}
2386
2387static struct pernet_operations tcp4_net_ops = {
2388 .init = tcp4_proc_init_net,
2389 .exit = tcp4_proc_exit_net,
2390};
2391
2392int __init tcp4_proc_init(void)
2393{
2394 return register_pernet_subsys(&tcp4_net_ops);
2395}
2396
2397void tcp4_proc_exit(void)
2398{
2399 unregister_pernet_subsys(&tcp4_net_ops);
2400}
2401#endif /* CONFIG_PROC_FS */
2402
2403struct proto tcp_prot = {
2404 .name = "TCP",
2405 .owner = THIS_MODULE,
2406 .close = tcp_close,
2407 .connect = tcp_v4_connect,
2408 .disconnect = tcp_disconnect,
2409 .accept = inet_csk_accept,
2410 .ioctl = tcp_ioctl,
2411 .init = tcp_v4_init_sock,
2412 .destroy = tcp_v4_destroy_sock,
2413 .shutdown = tcp_shutdown,
2414 .setsockopt = tcp_setsockopt,
2415 .getsockopt = tcp_getsockopt,
2416 .keepalive = tcp_set_keepalive,
2417 .recvmsg = tcp_recvmsg,
2418 .sendmsg = tcp_sendmsg,
2419 .sendpage = tcp_sendpage,
2420 .backlog_rcv = tcp_v4_do_rcv,
2421 .release_cb = tcp_release_cb,
2422 .hash = inet_hash,
2423 .unhash = inet_unhash,
2424 .get_port = inet_csk_get_port,
2425 .enter_memory_pressure = tcp_enter_memory_pressure,
2426 .leave_memory_pressure = tcp_leave_memory_pressure,
2427 .stream_memory_free = tcp_stream_memory_free,
2428 .sockets_allocated = &tcp_sockets_allocated,
2429 .orphan_count = &tcp_orphan_count,
2430 .memory_allocated = &tcp_memory_allocated,
2431 .memory_pressure = &tcp_memory_pressure,
2432 .sysctl_mem = sysctl_tcp_mem,
2433 .sysctl_wmem_offset = offsetof(struct net, ipv4.sysctl_tcp_wmem),
2434 .sysctl_rmem_offset = offsetof(struct net, ipv4.sysctl_tcp_rmem),
2435 .max_header = MAX_TCP_HEADER,
2436 .obj_size = sizeof(struct tcp_sock),
2437 .slab_flags = SLAB_TYPESAFE_BY_RCU,
2438 .twsk_prot = &tcp_timewait_sock_ops,
2439 .rsk_prot = &tcp_request_sock_ops,
2440 .h.hashinfo = &tcp_hashinfo,
2441 .no_autobind = true,
2442#ifdef CONFIG_COMPAT
2443 .compat_setsockopt = compat_tcp_setsockopt,
2444 .compat_getsockopt = compat_tcp_getsockopt,
2445#endif
2446 .diag_destroy = tcp_abort,
2447};
2448EXPORT_SYMBOL(tcp_prot);
2449
2450static void __net_exit tcp_sk_exit(struct net *net)
2451{
2452 int cpu;
2453
2454 module_put(net->ipv4.tcp_congestion_control->owner);
2455
2456 for_each_possible_cpu(cpu)
2457 inet_ctl_sock_destroy(*per_cpu_ptr(net->ipv4.tcp_sk, cpu));
2458 free_percpu(net->ipv4.tcp_sk);
2459}
2460
2461static int __net_init tcp_sk_init(struct net *net)
2462{
2463 int res, cpu, cnt;
2464
2465 net->ipv4.tcp_sk = alloc_percpu(struct sock *);
2466 if (!net->ipv4.tcp_sk)
2467 return -ENOMEM;
2468
2469 for_each_possible_cpu(cpu) {
2470 struct sock *sk;
2471
2472 res = inet_ctl_sock_create(&sk, PF_INET, SOCK_RAW,
2473 IPPROTO_TCP, net);
2474 if (res)
2475 goto fail;
2476 sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
2477 *per_cpu_ptr(net->ipv4.tcp_sk, cpu) = sk;
2478 }
2479
2480 net->ipv4.sysctl_tcp_ecn = 2;
2481 net->ipv4.sysctl_tcp_ecn_fallback = 1;
2482
2483 net->ipv4.sysctl_tcp_base_mss = TCP_BASE_MSS;
2484 net->ipv4.sysctl_tcp_probe_threshold = TCP_PROBE_THRESHOLD;
2485 net->ipv4.sysctl_tcp_probe_interval = TCP_PROBE_INTERVAL;
2486
2487 net->ipv4.sysctl_tcp_keepalive_time = TCP_KEEPALIVE_TIME;
2488 net->ipv4.sysctl_tcp_keepalive_probes = TCP_KEEPALIVE_PROBES;
2489 net->ipv4.sysctl_tcp_keepalive_intvl = TCP_KEEPALIVE_INTVL;
2490
2491 net->ipv4.sysctl_tcp_syn_retries = TCP_SYN_RETRIES;
2492 net->ipv4.sysctl_tcp_synack_retries = TCP_SYNACK_RETRIES;
2493 net->ipv4.sysctl_tcp_syncookies = 1;
2494 net->ipv4.sysctl_tcp_reordering = TCP_FASTRETRANS_THRESH;
2495 net->ipv4.sysctl_tcp_retries1 = TCP_RETR1;
2496 net->ipv4.sysctl_tcp_retries2 = TCP_RETR2;
2497 net->ipv4.sysctl_tcp_orphan_retries = 0;
2498 net->ipv4.sysctl_tcp_fin_timeout = TCP_FIN_TIMEOUT;
2499 net->ipv4.sysctl_tcp_notsent_lowat = UINT_MAX;
2500 net->ipv4.sysctl_tcp_tw_reuse = 0;
2501
2502 cnt = tcp_hashinfo.ehash_mask + 1;
2503 net->ipv4.tcp_death_row.sysctl_max_tw_buckets = (cnt + 1) / 2;
2504 net->ipv4.tcp_death_row.hashinfo = &tcp_hashinfo;
2505
2506 net->ipv4.sysctl_max_syn_backlog = max(128, cnt / 256);
2507 net->ipv4.sysctl_tcp_sack = 1;
2508 net->ipv4.sysctl_tcp_window_scaling = 1;
2509 net->ipv4.sysctl_tcp_timestamps = 1;
2510 net->ipv4.sysctl_tcp_early_retrans = 3;
2511 net->ipv4.sysctl_tcp_recovery = TCP_RACK_LOSS_DETECTION;
2512 net->ipv4.sysctl_tcp_slow_start_after_idle = 1; /* By default, RFC2861 behavior. */
2513 net->ipv4.sysctl_tcp_retrans_collapse = 1;
2514 net->ipv4.sysctl_tcp_max_reordering = 300;
2515 net->ipv4.sysctl_tcp_dsack = 1;
2516 net->ipv4.sysctl_tcp_app_win = 31;
2517 net->ipv4.sysctl_tcp_adv_win_scale = 1;
2518 net->ipv4.sysctl_tcp_frto = 2;
2519 net->ipv4.sysctl_tcp_moderate_rcvbuf = 1;
2520 /* This limits the percentage of the congestion window which we
2521 * will allow a single TSO frame to consume. Building TSO frames
2522 * which are too large can cause TCP streams to be bursty.
2523 */
2524 net->ipv4.sysctl_tcp_tso_win_divisor = 3;
2525 /* Default TSQ limit of four TSO segments */
2526 net->ipv4.sysctl_tcp_limit_output_bytes = 262144;
2527 /* rfc5961 challenge ack rate limiting */
2528 net->ipv4.sysctl_tcp_challenge_ack_limit = 1000;
2529 net->ipv4.sysctl_tcp_min_tso_segs = 2;
2530 net->ipv4.sysctl_tcp_min_rtt_wlen = 300;
2531 net->ipv4.sysctl_tcp_autocorking = 1;
2532 net->ipv4.sysctl_tcp_invalid_ratelimit = HZ/2;
2533 net->ipv4.sysctl_tcp_pacing_ss_ratio = 200;
2534 net->ipv4.sysctl_tcp_pacing_ca_ratio = 120;
2535 if (net != &init_net) {
2536 memcpy(net->ipv4.sysctl_tcp_rmem,
2537 init_net.ipv4.sysctl_tcp_rmem,
2538 sizeof(init_net.ipv4.sysctl_tcp_rmem));
2539 memcpy(net->ipv4.sysctl_tcp_wmem,
2540 init_net.ipv4.sysctl_tcp_wmem,
2541 sizeof(init_net.ipv4.sysctl_tcp_wmem));
2542 }
2543 net->ipv4.sysctl_tcp_fastopen = TFO_CLIENT_ENABLE;
2544 spin_lock_init(&net->ipv4.tcp_fastopen_ctx_lock);
2545 net->ipv4.sysctl_tcp_fastopen_blackhole_timeout = 60 * 60;
2546 atomic_set(&net->ipv4.tfo_active_disable_times, 0);
2547
2548 /* Reno is always built in */
2549 if (!net_eq(net, &init_net) &&
2550 try_module_get(init_net.ipv4.tcp_congestion_control->owner))
2551 net->ipv4.tcp_congestion_control = init_net.ipv4.tcp_congestion_control;
2552 else
2553 net->ipv4.tcp_congestion_control = &tcp_reno;
2554
2555 return 0;
2556fail:
2557 tcp_sk_exit(net);
2558
2559 return res;
2560}
2561
2562static void __net_exit tcp_sk_exit_batch(struct list_head *net_exit_list)
2563{
2564 struct net *net;
2565
2566 inet_twsk_purge(&tcp_hashinfo, AF_INET);
2567
2568 list_for_each_entry(net, net_exit_list, exit_list)
2569 tcp_fastopen_ctx_destroy(net);
2570}
2571
2572static struct pernet_operations __net_initdata tcp_sk_ops = {
2573 .init = tcp_sk_init,
2574 .exit = tcp_sk_exit,
2575 .exit_batch = tcp_sk_exit_batch,
2576};
2577
2578void __init tcp_v4_init(void)
2579{
2580 if (register_pernet_subsys(&tcp_sk_ops))
2581 panic("Failed to create the TCP control socket.\n");
2582}
2583