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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * INET An implementation of the TCP/IP protocol suite for the LINUX
4 * operating system. INET is implemented using the BSD Socket
5 * interface as the means of communication with the user level.
6 *
7 * Implementation of the Transmission Control Protocol(TCP).
8 *
9 * IPv4 specific functions
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
19/*
20 * Changes:
21 * David S. Miller : New socket lookup architecture.
22 * This code is dedicated to John Dyson.
23 * David S. Miller : Change semantics of established hash,
24 * half is devoted to TIME_WAIT sockets
25 * and the rest go in the other half.
26 * Andi Kleen : Add support for syncookies and fixed
27 * some bugs: ip options weren't passed to
28 * the TCP layer, missed a check for an
29 * ACK bit.
30 * Andi Kleen : Implemented fast path mtu discovery.
31 * Fixed many serious bugs in the
32 * request_sock handling and moved
33 * most of it into the af independent code.
34 * Added tail drop and some other bugfixes.
35 * Added new listen semantics.
36 * Mike McLagan : Routing by source
37 * Juan Jose Ciarlante: ip_dynaddr bits
38 * Andi Kleen: various fixes.
39 * Vitaly E. Lavrov : Transparent proxy revived after year
40 * coma.
41 * Andi Kleen : Fix new listen.
42 * Andi Kleen : Fix accept error reporting.
43 * YOSHIFUJI Hideaki @USAGI and: Support IPV6_V6ONLY socket option, which
44 * Alexey Kuznetsov allow both IPv4 and IPv6 sockets to bind
45 * a single port at the same time.
46 */
47
48#define pr_fmt(fmt) "TCP: " fmt
49
50#include <linux/bottom_half.h>
51#include <linux/types.h>
52#include <linux/fcntl.h>
53#include <linux/module.h>
54#include <linux/random.h>
55#include <linux/cache.h>
56#include <linux/jhash.h>
57#include <linux/init.h>
58#include <linux/times.h>
59#include <linux/slab.h>
60
61#include <net/net_namespace.h>
62#include <net/icmp.h>
63#include <net/inet_hashtables.h>
64#include <net/tcp.h>
65#include <net/transp_v6.h>
66#include <net/ipv6.h>
67#include <net/inet_common.h>
68#include <net/timewait_sock.h>
69#include <net/xfrm.h>
70#include <net/secure_seq.h>
71#include <net/busy_poll.h>
72
73#include <linux/inet.h>
74#include <linux/ipv6.h>
75#include <linux/stddef.h>
76#include <linux/proc_fs.h>
77#include <linux/seq_file.h>
78#include <linux/inetdevice.h>
79#include <linux/btf_ids.h>
80
81#include <crypto/hash.h>
82#include <linux/scatterlist.h>
83
84#include <trace/events/tcp.h>
85
86#ifdef CONFIG_TCP_MD5SIG
87static int tcp_v4_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key,
88 __be32 daddr, __be32 saddr, const struct tcphdr *th);
89#endif
90
91struct inet_hashinfo tcp_hashinfo;
92EXPORT_SYMBOL(tcp_hashinfo);
93
94static u32 tcp_v4_init_seq(const struct sk_buff *skb)
95{
96 return secure_tcp_seq(ip_hdr(skb)->daddr,
97 ip_hdr(skb)->saddr,
98 tcp_hdr(skb)->dest,
99 tcp_hdr(skb)->source);
100}
101
102static u32 tcp_v4_init_ts_off(const struct net *net, const struct sk_buff *skb)
103{
104 return secure_tcp_ts_off(net, ip_hdr(skb)->daddr, ip_hdr(skb)->saddr);
105}
106
107int tcp_twsk_unique(struct sock *sk, struct sock *sktw, void *twp)
108{
109 const struct inet_timewait_sock *tw = inet_twsk(sktw);
110 const struct tcp_timewait_sock *tcptw = tcp_twsk(sktw);
111 struct tcp_sock *tp = tcp_sk(sk);
112 int reuse = sock_net(sk)->ipv4.sysctl_tcp_tw_reuse;
113
114 if (reuse == 2) {
115 /* Still does not detect *everything* that goes through
116 * lo, since we require a loopback src or dst address
117 * or direct binding to 'lo' interface.
118 */
119 bool loopback = false;
120 if (tw->tw_bound_dev_if == LOOPBACK_IFINDEX)
121 loopback = true;
122#if IS_ENABLED(CONFIG_IPV6)
123 if (tw->tw_family == AF_INET6) {
124 if (ipv6_addr_loopback(&tw->tw_v6_daddr) ||
125 ipv6_addr_v4mapped_loopback(&tw->tw_v6_daddr) ||
126 ipv6_addr_loopback(&tw->tw_v6_rcv_saddr) ||
127 ipv6_addr_v4mapped_loopback(&tw->tw_v6_rcv_saddr))
128 loopback = true;
129 } else
130#endif
131 {
132 if (ipv4_is_loopback(tw->tw_daddr) ||
133 ipv4_is_loopback(tw->tw_rcv_saddr))
134 loopback = true;
135 }
136 if (!loopback)
137 reuse = 0;
138 }
139
140 /* With PAWS, it is safe from the viewpoint
141 of data integrity. Even without PAWS it is safe provided sequence
142 spaces do not overlap i.e. at data rates <= 80Mbit/sec.
143
144 Actually, the idea is close to VJ's one, only timestamp cache is
145 held not per host, but per port pair and TW bucket is used as state
146 holder.
147
148 If TW bucket has been already destroyed we fall back to VJ's scheme
149 and use initial timestamp retrieved from peer table.
150 */
151 if (tcptw->tw_ts_recent_stamp &&
152 (!twp || (reuse && time_after32(ktime_get_seconds(),
153 tcptw->tw_ts_recent_stamp)))) {
154 /* In case of repair and re-using TIME-WAIT sockets we still
155 * want to be sure that it is safe as above but honor the
156 * sequence numbers and time stamps set as part of the repair
157 * process.
158 *
159 * Without this check re-using a TIME-WAIT socket with TCP
160 * repair would accumulate a -1 on the repair assigned
161 * sequence number. The first time it is reused the sequence
162 * is -1, the second time -2, etc. This fixes that issue
163 * without appearing to create any others.
164 */
165 if (likely(!tp->repair)) {
166 u32 seq = tcptw->tw_snd_nxt + 65535 + 2;
167
168 if (!seq)
169 seq = 1;
170 WRITE_ONCE(tp->write_seq, seq);
171 tp->rx_opt.ts_recent = tcptw->tw_ts_recent;
172 tp->rx_opt.ts_recent_stamp = tcptw->tw_ts_recent_stamp;
173 }
174 sock_hold(sktw);
175 return 1;
176 }
177
178 return 0;
179}
180EXPORT_SYMBOL_GPL(tcp_twsk_unique);
181
182static int tcp_v4_pre_connect(struct sock *sk, struct sockaddr *uaddr,
183 int addr_len)
184{
185 /* This check is replicated from tcp_v4_connect() and intended to
186 * prevent BPF program called below from accessing bytes that are out
187 * of the bound specified by user in addr_len.
188 */
189 if (addr_len < sizeof(struct sockaddr_in))
190 return -EINVAL;
191
192 sock_owned_by_me(sk);
193
194 return BPF_CGROUP_RUN_PROG_INET4_CONNECT(sk, uaddr);
195}
196
197/* This will initiate an outgoing connection. */
198int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
199{
200 struct sockaddr_in *usin = (struct sockaddr_in *)uaddr;
201 struct inet_sock *inet = inet_sk(sk);
202 struct tcp_sock *tp = tcp_sk(sk);
203 __be16 orig_sport, orig_dport;
204 __be32 daddr, nexthop;
205 struct flowi4 *fl4;
206 struct rtable *rt;
207 int err;
208 struct ip_options_rcu *inet_opt;
209 struct inet_timewait_death_row *tcp_death_row = &sock_net(sk)->ipv4.tcp_death_row;
210
211 if (addr_len < sizeof(struct sockaddr_in))
212 return -EINVAL;
213
214 if (usin->sin_family != AF_INET)
215 return -EAFNOSUPPORT;
216
217 nexthop = daddr = usin->sin_addr.s_addr;
218 inet_opt = rcu_dereference_protected(inet->inet_opt,
219 lockdep_sock_is_held(sk));
220 if (inet_opt && inet_opt->opt.srr) {
221 if (!daddr)
222 return -EINVAL;
223 nexthop = inet_opt->opt.faddr;
224 }
225
226 orig_sport = inet->inet_sport;
227 orig_dport = usin->sin_port;
228 fl4 = &inet->cork.fl.u.ip4;
229 rt = ip_route_connect(fl4, nexthop, inet->inet_saddr,
230 RT_CONN_FLAGS(sk), sk->sk_bound_dev_if,
231 IPPROTO_TCP,
232 orig_sport, orig_dport, sk);
233 if (IS_ERR(rt)) {
234 err = PTR_ERR(rt);
235 if (err == -ENETUNREACH)
236 IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTNOROUTES);
237 return err;
238 }
239
240 if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) {
241 ip_rt_put(rt);
242 return -ENETUNREACH;
243 }
244
245 if (!inet_opt || !inet_opt->opt.srr)
246 daddr = fl4->daddr;
247
248 if (!inet->inet_saddr)
249 inet->inet_saddr = fl4->saddr;
250 sk_rcv_saddr_set(sk, inet->inet_saddr);
251
252 if (tp->rx_opt.ts_recent_stamp && inet->inet_daddr != daddr) {
253 /* Reset inherited state */
254 tp->rx_opt.ts_recent = 0;
255 tp->rx_opt.ts_recent_stamp = 0;
256 if (likely(!tp->repair))
257 WRITE_ONCE(tp->write_seq, 0);
258 }
259
260 inet->inet_dport = usin->sin_port;
261 sk_daddr_set(sk, daddr);
262
263 inet_csk(sk)->icsk_ext_hdr_len = 0;
264 if (inet_opt)
265 inet_csk(sk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
266
267 tp->rx_opt.mss_clamp = TCP_MSS_DEFAULT;
268
269 /* Socket identity is still unknown (sport may be zero).
270 * However we set state to SYN-SENT and not releasing socket
271 * lock select source port, enter ourselves into the hash tables and
272 * complete initialization after this.
273 */
274 tcp_set_state(sk, TCP_SYN_SENT);
275 err = inet_hash_connect(tcp_death_row, sk);
276 if (err)
277 goto failure;
278
279 sk_set_txhash(sk);
280
281 rt = ip_route_newports(fl4, rt, orig_sport, orig_dport,
282 inet->inet_sport, inet->inet_dport, sk);
283 if (IS_ERR(rt)) {
284 err = PTR_ERR(rt);
285 rt = NULL;
286 goto failure;
287 }
288 /* OK, now commit destination to socket. */
289 sk->sk_gso_type = SKB_GSO_TCPV4;
290 sk_setup_caps(sk, &rt->dst);
291 rt = NULL;
292
293 if (likely(!tp->repair)) {
294 if (!tp->write_seq)
295 WRITE_ONCE(tp->write_seq,
296 secure_tcp_seq(inet->inet_saddr,
297 inet->inet_daddr,
298 inet->inet_sport,
299 usin->sin_port));
300 tp->tsoffset = secure_tcp_ts_off(sock_net(sk),
301 inet->inet_saddr,
302 inet->inet_daddr);
303 }
304
305 inet->inet_id = prandom_u32();
306
307 if (tcp_fastopen_defer_connect(sk, &err))
308 return err;
309 if (err)
310 goto failure;
311
312 err = tcp_connect(sk);
313
314 if (err)
315 goto failure;
316
317 return 0;
318
319failure:
320 /*
321 * This unhashes the socket and releases the local port,
322 * if necessary.
323 */
324 tcp_set_state(sk, TCP_CLOSE);
325 ip_rt_put(rt);
326 sk->sk_route_caps = 0;
327 inet->inet_dport = 0;
328 return err;
329}
330EXPORT_SYMBOL(tcp_v4_connect);
331
332/*
333 * This routine reacts to ICMP_FRAG_NEEDED mtu indications as defined in RFC1191.
334 * It can be called through tcp_release_cb() if socket was owned by user
335 * at the time tcp_v4_err() was called to handle ICMP message.
336 */
337void tcp_v4_mtu_reduced(struct sock *sk)
338{
339 struct inet_sock *inet = inet_sk(sk);
340 struct dst_entry *dst;
341 u32 mtu;
342
343 if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE))
344 return;
345 mtu = tcp_sk(sk)->mtu_info;
346 dst = inet_csk_update_pmtu(sk, mtu);
347 if (!dst)
348 return;
349
350 /* Something is about to be wrong... Remember soft error
351 * for the case, if this connection will not able to recover.
352 */
353 if (mtu < dst_mtu(dst) && ip_dont_fragment(sk, dst))
354 sk->sk_err_soft = EMSGSIZE;
355
356 mtu = dst_mtu(dst);
357
358 if (inet->pmtudisc != IP_PMTUDISC_DONT &&
359 ip_sk_accept_pmtu(sk) &&
360 inet_csk(sk)->icsk_pmtu_cookie > mtu) {
361 tcp_sync_mss(sk, mtu);
362
363 /* Resend the TCP packet because it's
364 * clear that the old packet has been
365 * dropped. This is the new "fast" path mtu
366 * discovery.
367 */
368 tcp_simple_retransmit(sk);
369 } /* else let the usual retransmit timer handle it */
370}
371EXPORT_SYMBOL(tcp_v4_mtu_reduced);
372
373static void do_redirect(struct sk_buff *skb, struct sock *sk)
374{
375 struct dst_entry *dst = __sk_dst_check(sk, 0);
376
377 if (dst)
378 dst->ops->redirect(dst, sk, skb);
379}
380
381
382/* handle ICMP messages on TCP_NEW_SYN_RECV request sockets */
383void tcp_req_err(struct sock *sk, u32 seq, bool abort)
384{
385 struct request_sock *req = inet_reqsk(sk);
386 struct net *net = sock_net(sk);
387
388 /* ICMPs are not backlogged, hence we cannot get
389 * an established socket here.
390 */
391 if (seq != tcp_rsk(req)->snt_isn) {
392 __NET_INC_STATS(net, LINUX_MIB_OUTOFWINDOWICMPS);
393 } else if (abort) {
394 /*
395 * Still in SYN_RECV, just remove it silently.
396 * There is no good way to pass the error to the newly
397 * created socket, and POSIX does not want network
398 * errors returned from accept().
399 */
400 inet_csk_reqsk_queue_drop(req->rsk_listener, req);
401 tcp_listendrop(req->rsk_listener);
402 }
403 reqsk_put(req);
404}
405EXPORT_SYMBOL(tcp_req_err);
406
407/* TCP-LD (RFC 6069) logic */
408void tcp_ld_RTO_revert(struct sock *sk, u32 seq)
409{
410 struct inet_connection_sock *icsk = inet_csk(sk);
411 struct tcp_sock *tp = tcp_sk(sk);
412 struct sk_buff *skb;
413 s32 remaining;
414 u32 delta_us;
415
416 if (sock_owned_by_user(sk))
417 return;
418
419 if (seq != tp->snd_una || !icsk->icsk_retransmits ||
420 !icsk->icsk_backoff)
421 return;
422
423 skb = tcp_rtx_queue_head(sk);
424 if (WARN_ON_ONCE(!skb))
425 return;
426
427 icsk->icsk_backoff--;
428 icsk->icsk_rto = tp->srtt_us ? __tcp_set_rto(tp) : TCP_TIMEOUT_INIT;
429 icsk->icsk_rto = inet_csk_rto_backoff(icsk, TCP_RTO_MAX);
430
431 tcp_mstamp_refresh(tp);
432 delta_us = (u32)(tp->tcp_mstamp - tcp_skb_timestamp_us(skb));
433 remaining = icsk->icsk_rto - usecs_to_jiffies(delta_us);
434
435 if (remaining > 0) {
436 inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
437 remaining, TCP_RTO_MAX);
438 } else {
439 /* RTO revert clocked out retransmission.
440 * Will retransmit now.
441 */
442 tcp_retransmit_timer(sk);
443 }
444}
445EXPORT_SYMBOL(tcp_ld_RTO_revert);
446
447/*
448 * This routine is called by the ICMP module when it gets some
449 * sort of error condition. If err < 0 then the socket should
450 * be closed and the error returned to the user. If err > 0
451 * it's just the icmp type << 8 | icmp code. After adjustment
452 * header points to the first 8 bytes of the tcp header. We need
453 * to find the appropriate port.
454 *
455 * The locking strategy used here is very "optimistic". When
456 * someone else accesses the socket the ICMP is just dropped
457 * and for some paths there is no check at all.
458 * A more general error queue to queue errors for later handling
459 * is probably better.
460 *
461 */
462
463int tcp_v4_err(struct sk_buff *skb, u32 info)
464{
465 const struct iphdr *iph = (const struct iphdr *)skb->data;
466 struct tcphdr *th = (struct tcphdr *)(skb->data + (iph->ihl << 2));
467 struct tcp_sock *tp;
468 struct inet_sock *inet;
469 const int type = icmp_hdr(skb)->type;
470 const int code = icmp_hdr(skb)->code;
471 struct sock *sk;
472 struct request_sock *fastopen;
473 u32 seq, snd_una;
474 int err;
475 struct net *net = dev_net(skb->dev);
476
477 sk = __inet_lookup_established(net, &tcp_hashinfo, iph->daddr,
478 th->dest, iph->saddr, ntohs(th->source),
479 inet_iif(skb), 0);
480 if (!sk) {
481 __ICMP_INC_STATS(net, ICMP_MIB_INERRORS);
482 return -ENOENT;
483 }
484 if (sk->sk_state == TCP_TIME_WAIT) {
485 inet_twsk_put(inet_twsk(sk));
486 return 0;
487 }
488 seq = ntohl(th->seq);
489 if (sk->sk_state == TCP_NEW_SYN_RECV) {
490 tcp_req_err(sk, seq, type == ICMP_PARAMETERPROB ||
491 type == ICMP_TIME_EXCEEDED ||
492 (type == ICMP_DEST_UNREACH &&
493 (code == ICMP_NET_UNREACH ||
494 code == ICMP_HOST_UNREACH)));
495 return 0;
496 }
497
498 bh_lock_sock(sk);
499 /* If too many ICMPs get dropped on busy
500 * servers this needs to be solved differently.
501 * We do take care of PMTU discovery (RFC1191) special case :
502 * we can receive locally generated ICMP messages while socket is held.
503 */
504 if (sock_owned_by_user(sk)) {
505 if (!(type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED))
506 __NET_INC_STATS(net, LINUX_MIB_LOCKDROPPEDICMPS);
507 }
508 if (sk->sk_state == TCP_CLOSE)
509 goto out;
510
511 if (unlikely(iph->ttl < inet_sk(sk)->min_ttl)) {
512 __NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP);
513 goto out;
514 }
515
516 tp = tcp_sk(sk);
517 /* XXX (TFO) - tp->snd_una should be ISN (tcp_create_openreq_child() */
518 fastopen = rcu_dereference(tp->fastopen_rsk);
519 snd_una = fastopen ? tcp_rsk(fastopen)->snt_isn : tp->snd_una;
520 if (sk->sk_state != TCP_LISTEN &&
521 !between(seq, snd_una, tp->snd_nxt)) {
522 __NET_INC_STATS(net, LINUX_MIB_OUTOFWINDOWICMPS);
523 goto out;
524 }
525
526 switch (type) {
527 case ICMP_REDIRECT:
528 if (!sock_owned_by_user(sk))
529 do_redirect(skb, sk);
530 goto out;
531 case ICMP_SOURCE_QUENCH:
532 /* Just silently ignore these. */
533 goto out;
534 case ICMP_PARAMETERPROB:
535 err = EPROTO;
536 break;
537 case ICMP_DEST_UNREACH:
538 if (code > NR_ICMP_UNREACH)
539 goto out;
540
541 if (code == ICMP_FRAG_NEEDED) { /* PMTU discovery (RFC1191) */
542 /* We are not interested in TCP_LISTEN and open_requests
543 * (SYN-ACKs send out by Linux are always <576bytes so
544 * they should go through unfragmented).
545 */
546 if (sk->sk_state == TCP_LISTEN)
547 goto out;
548
549 tp->mtu_info = info;
550 if (!sock_owned_by_user(sk)) {
551 tcp_v4_mtu_reduced(sk);
552 } else {
553 if (!test_and_set_bit(TCP_MTU_REDUCED_DEFERRED, &sk->sk_tsq_flags))
554 sock_hold(sk);
555 }
556 goto out;
557 }
558
559 err = icmp_err_convert[code].errno;
560 /* check if this ICMP message allows revert of backoff.
561 * (see RFC 6069)
562 */
563 if (!fastopen &&
564 (code == ICMP_NET_UNREACH || code == ICMP_HOST_UNREACH))
565 tcp_ld_RTO_revert(sk, seq);
566 break;
567 case ICMP_TIME_EXCEEDED:
568 err = EHOSTUNREACH;
569 break;
570 default:
571 goto out;
572 }
573
574 switch (sk->sk_state) {
575 case TCP_SYN_SENT:
576 case TCP_SYN_RECV:
577 /* Only in fast or simultaneous open. If a fast open socket is
578 * is already accepted it is treated as a connected one below.
579 */
580 if (fastopen && !fastopen->sk)
581 break;
582
583 ip_icmp_error(sk, skb, err, th->dest, info, (u8 *)th);
584
585 if (!sock_owned_by_user(sk)) {
586 sk->sk_err = err;
587
588 sk->sk_error_report(sk);
589
590 tcp_done(sk);
591 } else {
592 sk->sk_err_soft = err;
593 }
594 goto out;
595 }
596
597 /* If we've already connected we will keep trying
598 * until we time out, or the user gives up.
599 *
600 * rfc1122 4.2.3.9 allows to consider as hard errors
601 * only PROTO_UNREACH and PORT_UNREACH (well, FRAG_FAILED too,
602 * but it is obsoleted by pmtu discovery).
603 *
604 * Note, that in modern internet, where routing is unreliable
605 * and in each dark corner broken firewalls sit, sending random
606 * errors ordered by their masters even this two messages finally lose
607 * their original sense (even Linux sends invalid PORT_UNREACHs)
608 *
609 * Now we are in compliance with RFCs.
610 * --ANK (980905)
611 */
612
613 inet = inet_sk(sk);
614 if (!sock_owned_by_user(sk) && inet->recverr) {
615 sk->sk_err = err;
616 sk->sk_error_report(sk);
617 } else { /* Only an error on timeout */
618 sk->sk_err_soft = err;
619 }
620
621out:
622 bh_unlock_sock(sk);
623 sock_put(sk);
624 return 0;
625}
626
627void __tcp_v4_send_check(struct sk_buff *skb, __be32 saddr, __be32 daddr)
628{
629 struct tcphdr *th = tcp_hdr(skb);
630
631 th->check = ~tcp_v4_check(skb->len, saddr, daddr, 0);
632 skb->csum_start = skb_transport_header(skb) - skb->head;
633 skb->csum_offset = offsetof(struct tcphdr, check);
634}
635
636/* This routine computes an IPv4 TCP checksum. */
637void tcp_v4_send_check(struct sock *sk, struct sk_buff *skb)
638{
639 const struct inet_sock *inet = inet_sk(sk);
640
641 __tcp_v4_send_check(skb, inet->inet_saddr, inet->inet_daddr);
642}
643EXPORT_SYMBOL(tcp_v4_send_check);
644
645/*
646 * This routine will send an RST to the other tcp.
647 *
648 * Someone asks: why I NEVER use socket parameters (TOS, TTL etc.)
649 * for reset.
650 * Answer: if a packet caused RST, it is not for a socket
651 * existing in our system, if it is matched to a socket,
652 * it is just duplicate segment or bug in other side's TCP.
653 * So that we build reply only basing on parameters
654 * arrived with segment.
655 * Exception: precedence violation. We do not implement it in any case.
656 */
657
658static void tcp_v4_send_reset(const struct sock *sk, struct sk_buff *skb)
659{
660 const struct tcphdr *th = tcp_hdr(skb);
661 struct {
662 struct tcphdr th;
663#ifdef CONFIG_TCP_MD5SIG
664 __be32 opt[(TCPOLEN_MD5SIG_ALIGNED >> 2)];
665#endif
666 } rep;
667 struct ip_reply_arg arg;
668#ifdef CONFIG_TCP_MD5SIG
669 struct tcp_md5sig_key *key = NULL;
670 const __u8 *hash_location = NULL;
671 unsigned char newhash[16];
672 int genhash;
673 struct sock *sk1 = NULL;
674#endif
675 u64 transmit_time = 0;
676 struct sock *ctl_sk;
677 struct net *net;
678
679 /* Never send a reset in response to a reset. */
680 if (th->rst)
681 return;
682
683 /* If sk not NULL, it means we did a successful lookup and incoming
684 * route had to be correct. prequeue might have dropped our dst.
685 */
686 if (!sk && skb_rtable(skb)->rt_type != RTN_LOCAL)
687 return;
688
689 /* Swap the send and the receive. */
690 memset(&rep, 0, sizeof(rep));
691 rep.th.dest = th->source;
692 rep.th.source = th->dest;
693 rep.th.doff = sizeof(struct tcphdr) / 4;
694 rep.th.rst = 1;
695
696 if (th->ack) {
697 rep.th.seq = th->ack_seq;
698 } else {
699 rep.th.ack = 1;
700 rep.th.ack_seq = htonl(ntohl(th->seq) + th->syn + th->fin +
701 skb->len - (th->doff << 2));
702 }
703
704 memset(&arg, 0, sizeof(arg));
705 arg.iov[0].iov_base = (unsigned char *)&rep;
706 arg.iov[0].iov_len = sizeof(rep.th);
707
708 net = sk ? sock_net(sk) : dev_net(skb_dst(skb)->dev);
709#ifdef CONFIG_TCP_MD5SIG
710 rcu_read_lock();
711 hash_location = tcp_parse_md5sig_option(th);
712 if (sk && sk_fullsock(sk)) {
713 const union tcp_md5_addr *addr;
714 int l3index;
715
716 /* sdif set, means packet ingressed via a device
717 * in an L3 domain and inet_iif is set to it.
718 */
719 l3index = tcp_v4_sdif(skb) ? inet_iif(skb) : 0;
720 addr = (union tcp_md5_addr *)&ip_hdr(skb)->saddr;
721 key = tcp_md5_do_lookup(sk, l3index, addr, AF_INET);
722 } else if (hash_location) {
723 const union tcp_md5_addr *addr;
724 int sdif = tcp_v4_sdif(skb);
725 int dif = inet_iif(skb);
726 int l3index;
727
728 /*
729 * active side is lost. Try to find listening socket through
730 * source port, and then find md5 key through listening socket.
731 * we are not loose security here:
732 * Incoming packet is checked with md5 hash with finding key,
733 * no RST generated if md5 hash doesn't match.
734 */
735 sk1 = __inet_lookup_listener(net, &tcp_hashinfo, NULL, 0,
736 ip_hdr(skb)->saddr,
737 th->source, ip_hdr(skb)->daddr,
738 ntohs(th->source), dif, sdif);
739 /* don't send rst if it can't find key */
740 if (!sk1)
741 goto out;
742
743 /* sdif set, means packet ingressed via a device
744 * in an L3 domain and dif is set to it.
745 */
746 l3index = sdif ? dif : 0;
747 addr = (union tcp_md5_addr *)&ip_hdr(skb)->saddr;
748 key = tcp_md5_do_lookup(sk1, l3index, addr, AF_INET);
749 if (!key)
750 goto out;
751
752
753 genhash = tcp_v4_md5_hash_skb(newhash, key, NULL, skb);
754 if (genhash || memcmp(hash_location, newhash, 16) != 0)
755 goto out;
756
757 }
758
759 if (key) {
760 rep.opt[0] = htonl((TCPOPT_NOP << 24) |
761 (TCPOPT_NOP << 16) |
762 (TCPOPT_MD5SIG << 8) |
763 TCPOLEN_MD5SIG);
764 /* Update length and the length the header thinks exists */
765 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED;
766 rep.th.doff = arg.iov[0].iov_len / 4;
767
768 tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[1],
769 key, ip_hdr(skb)->saddr,
770 ip_hdr(skb)->daddr, &rep.th);
771 }
772#endif
773 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
774 ip_hdr(skb)->saddr, /* XXX */
775 arg.iov[0].iov_len, IPPROTO_TCP, 0);
776 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
777 arg.flags = (sk && inet_sk_transparent(sk)) ? IP_REPLY_ARG_NOSRCCHECK : 0;
778
779 /* When socket is gone, all binding information is lost.
780 * routing might fail in this case. No choice here, if we choose to force
781 * input interface, we will misroute in case of asymmetric route.
782 */
783 if (sk) {
784 arg.bound_dev_if = sk->sk_bound_dev_if;
785 if (sk_fullsock(sk))
786 trace_tcp_send_reset(sk, skb);
787 }
788
789 BUILD_BUG_ON(offsetof(struct sock, sk_bound_dev_if) !=
790 offsetof(struct inet_timewait_sock, tw_bound_dev_if));
791
792 arg.tos = ip_hdr(skb)->tos;
793 arg.uid = sock_net_uid(net, sk && sk_fullsock(sk) ? sk : NULL);
794 local_bh_disable();
795 ctl_sk = this_cpu_read(*net->ipv4.tcp_sk);
796 if (sk) {
797 ctl_sk->sk_mark = (sk->sk_state == TCP_TIME_WAIT) ?
798 inet_twsk(sk)->tw_mark : sk->sk_mark;
799 ctl_sk->sk_priority = (sk->sk_state == TCP_TIME_WAIT) ?
800 inet_twsk(sk)->tw_priority : sk->sk_priority;
801 transmit_time = tcp_transmit_time(sk);
802 }
803 ip_send_unicast_reply(ctl_sk,
804 skb, &TCP_SKB_CB(skb)->header.h4.opt,
805 ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
806 &arg, arg.iov[0].iov_len,
807 transmit_time);
808
809 ctl_sk->sk_mark = 0;
810 __TCP_INC_STATS(net, TCP_MIB_OUTSEGS);
811 __TCP_INC_STATS(net, TCP_MIB_OUTRSTS);
812 local_bh_enable();
813
814#ifdef CONFIG_TCP_MD5SIG
815out:
816 rcu_read_unlock();
817#endif
818}
819
820/* The code following below sending ACKs in SYN-RECV and TIME-WAIT states
821 outside socket context is ugly, certainly. What can I do?
822 */
823
824static void tcp_v4_send_ack(const struct sock *sk,
825 struct sk_buff *skb, u32 seq, u32 ack,
826 u32 win, u32 tsval, u32 tsecr, int oif,
827 struct tcp_md5sig_key *key,
828 int reply_flags, u8 tos)
829{
830 const struct tcphdr *th = tcp_hdr(skb);
831 struct {
832 struct tcphdr th;
833 __be32 opt[(TCPOLEN_TSTAMP_ALIGNED >> 2)
834#ifdef CONFIG_TCP_MD5SIG
835 + (TCPOLEN_MD5SIG_ALIGNED >> 2)
836#endif
837 ];
838 } rep;
839 struct net *net = sock_net(sk);
840 struct ip_reply_arg arg;
841 struct sock *ctl_sk;
842 u64 transmit_time;
843
844 memset(&rep.th, 0, sizeof(struct tcphdr));
845 memset(&arg, 0, sizeof(arg));
846
847 arg.iov[0].iov_base = (unsigned char *)&rep;
848 arg.iov[0].iov_len = sizeof(rep.th);
849 if (tsecr) {
850 rep.opt[0] = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
851 (TCPOPT_TIMESTAMP << 8) |
852 TCPOLEN_TIMESTAMP);
853 rep.opt[1] = htonl(tsval);
854 rep.opt[2] = htonl(tsecr);
855 arg.iov[0].iov_len += TCPOLEN_TSTAMP_ALIGNED;
856 }
857
858 /* Swap the send and the receive. */
859 rep.th.dest = th->source;
860 rep.th.source = th->dest;
861 rep.th.doff = arg.iov[0].iov_len / 4;
862 rep.th.seq = htonl(seq);
863 rep.th.ack_seq = htonl(ack);
864 rep.th.ack = 1;
865 rep.th.window = htons(win);
866
867#ifdef CONFIG_TCP_MD5SIG
868 if (key) {
869 int offset = (tsecr) ? 3 : 0;
870
871 rep.opt[offset++] = htonl((TCPOPT_NOP << 24) |
872 (TCPOPT_NOP << 16) |
873 (TCPOPT_MD5SIG << 8) |
874 TCPOLEN_MD5SIG);
875 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED;
876 rep.th.doff = arg.iov[0].iov_len/4;
877
878 tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[offset],
879 key, ip_hdr(skb)->saddr,
880 ip_hdr(skb)->daddr, &rep.th);
881 }
882#endif
883 arg.flags = reply_flags;
884 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
885 ip_hdr(skb)->saddr, /* XXX */
886 arg.iov[0].iov_len, IPPROTO_TCP, 0);
887 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
888 if (oif)
889 arg.bound_dev_if = oif;
890 arg.tos = tos;
891 arg.uid = sock_net_uid(net, sk_fullsock(sk) ? sk : NULL);
892 local_bh_disable();
893 ctl_sk = this_cpu_read(*net->ipv4.tcp_sk);
894 ctl_sk->sk_mark = (sk->sk_state == TCP_TIME_WAIT) ?
895 inet_twsk(sk)->tw_mark : sk->sk_mark;
896 ctl_sk->sk_priority = (sk->sk_state == TCP_TIME_WAIT) ?
897 inet_twsk(sk)->tw_priority : sk->sk_priority;
898 transmit_time = tcp_transmit_time(sk);
899 ip_send_unicast_reply(ctl_sk,
900 skb, &TCP_SKB_CB(skb)->header.h4.opt,
901 ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
902 &arg, arg.iov[0].iov_len,
903 transmit_time);
904
905 ctl_sk->sk_mark = 0;
906 __TCP_INC_STATS(net, TCP_MIB_OUTSEGS);
907 local_bh_enable();
908}
909
910static void tcp_v4_timewait_ack(struct sock *sk, struct sk_buff *skb)
911{
912 struct inet_timewait_sock *tw = inet_twsk(sk);
913 struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
914
915 tcp_v4_send_ack(sk, skb,
916 tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
917 tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
918 tcp_time_stamp_raw() + tcptw->tw_ts_offset,
919 tcptw->tw_ts_recent,
920 tw->tw_bound_dev_if,
921 tcp_twsk_md5_key(tcptw),
922 tw->tw_transparent ? IP_REPLY_ARG_NOSRCCHECK : 0,
923 tw->tw_tos
924 );
925
926 inet_twsk_put(tw);
927}
928
929static void tcp_v4_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb,
930 struct request_sock *req)
931{
932 const union tcp_md5_addr *addr;
933 int l3index;
934
935 /* sk->sk_state == TCP_LISTEN -> for regular TCP_SYN_RECV
936 * sk->sk_state == TCP_SYN_RECV -> for Fast Open.
937 */
938 u32 seq = (sk->sk_state == TCP_LISTEN) ? tcp_rsk(req)->snt_isn + 1 :
939 tcp_sk(sk)->snd_nxt;
940
941 /* RFC 7323 2.3
942 * The window field (SEG.WND) of every outgoing segment, with the
943 * exception of <SYN> segments, MUST be right-shifted by
944 * Rcv.Wind.Shift bits:
945 */
946 addr = (union tcp_md5_addr *)&ip_hdr(skb)->saddr;
947 l3index = tcp_v4_sdif(skb) ? inet_iif(skb) : 0;
948 tcp_v4_send_ack(sk, skb, seq,
949 tcp_rsk(req)->rcv_nxt,
950 req->rsk_rcv_wnd >> inet_rsk(req)->rcv_wscale,
951 tcp_time_stamp_raw() + tcp_rsk(req)->ts_off,
952 req->ts_recent,
953 0,
954 tcp_md5_do_lookup(sk, l3index, addr, AF_INET),
955 inet_rsk(req)->no_srccheck ? IP_REPLY_ARG_NOSRCCHECK : 0,
956 ip_hdr(skb)->tos);
957}
958
959/*
960 * Send a SYN-ACK after having received a SYN.
961 * This still operates on a request_sock only, not on a big
962 * socket.
963 */
964static int tcp_v4_send_synack(const struct sock *sk, struct dst_entry *dst,
965 struct flowi *fl,
966 struct request_sock *req,
967 struct tcp_fastopen_cookie *foc,
968 enum tcp_synack_type synack_type)
969{
970 const struct inet_request_sock *ireq = inet_rsk(req);
971 struct flowi4 fl4;
972 int err = -1;
973 struct sk_buff *skb;
974
975 /* First, grab a route. */
976 if (!dst && (dst = inet_csk_route_req(sk, &fl4, req)) == NULL)
977 return -1;
978
979 skb = tcp_make_synack(sk, dst, req, foc, synack_type);
980
981 if (skb) {
982 __tcp_v4_send_check(skb, ireq->ir_loc_addr, ireq->ir_rmt_addr);
983
984 rcu_read_lock();
985 err = ip_build_and_send_pkt(skb, sk, ireq->ir_loc_addr,
986 ireq->ir_rmt_addr,
987 rcu_dereference(ireq->ireq_opt));
988 rcu_read_unlock();
989 err = net_xmit_eval(err);
990 }
991
992 return err;
993}
994
995/*
996 * IPv4 request_sock destructor.
997 */
998static void tcp_v4_reqsk_destructor(struct request_sock *req)
999{
1000 kfree(rcu_dereference_protected(inet_rsk(req)->ireq_opt, 1));
1001}
1002
1003#ifdef CONFIG_TCP_MD5SIG
1004/*
1005 * RFC2385 MD5 checksumming requires a mapping of
1006 * IP address->MD5 Key.
1007 * We need to maintain these in the sk structure.
1008 */
1009
1010DEFINE_STATIC_KEY_FALSE(tcp_md5_needed);
1011EXPORT_SYMBOL(tcp_md5_needed);
1012
1013/* Find the Key structure for an address. */
1014struct tcp_md5sig_key *__tcp_md5_do_lookup(const struct sock *sk, int l3index,
1015 const union tcp_md5_addr *addr,
1016 int family)
1017{
1018 const struct tcp_sock *tp = tcp_sk(sk);
1019 struct tcp_md5sig_key *key;
1020 const struct tcp_md5sig_info *md5sig;
1021 __be32 mask;
1022 struct tcp_md5sig_key *best_match = NULL;
1023 bool match;
1024
1025 /* caller either holds rcu_read_lock() or socket lock */
1026 md5sig = rcu_dereference_check(tp->md5sig_info,
1027 lockdep_sock_is_held(sk));
1028 if (!md5sig)
1029 return NULL;
1030
1031 hlist_for_each_entry_rcu(key, &md5sig->head, node,
1032 lockdep_sock_is_held(sk)) {
1033 if (key->family != family)
1034 continue;
1035 if (key->l3index && key->l3index != l3index)
1036 continue;
1037 if (family == AF_INET) {
1038 mask = inet_make_mask(key->prefixlen);
1039 match = (key->addr.a4.s_addr & mask) ==
1040 (addr->a4.s_addr & mask);
1041#if IS_ENABLED(CONFIG_IPV6)
1042 } else if (family == AF_INET6) {
1043 match = ipv6_prefix_equal(&key->addr.a6, &addr->a6,
1044 key->prefixlen);
1045#endif
1046 } else {
1047 match = false;
1048 }
1049
1050 if (match && (!best_match ||
1051 key->prefixlen > best_match->prefixlen))
1052 best_match = key;
1053 }
1054 return best_match;
1055}
1056EXPORT_SYMBOL(__tcp_md5_do_lookup);
1057
1058static struct tcp_md5sig_key *tcp_md5_do_lookup_exact(const struct sock *sk,
1059 const union tcp_md5_addr *addr,
1060 int family, u8 prefixlen,
1061 int l3index)
1062{
1063 const struct tcp_sock *tp = tcp_sk(sk);
1064 struct tcp_md5sig_key *key;
1065 unsigned int size = sizeof(struct in_addr);
1066 const struct tcp_md5sig_info *md5sig;
1067
1068 /* caller either holds rcu_read_lock() or socket lock */
1069 md5sig = rcu_dereference_check(tp->md5sig_info,
1070 lockdep_sock_is_held(sk));
1071 if (!md5sig)
1072 return NULL;
1073#if IS_ENABLED(CONFIG_IPV6)
1074 if (family == AF_INET6)
1075 size = sizeof(struct in6_addr);
1076#endif
1077 hlist_for_each_entry_rcu(key, &md5sig->head, node,
1078 lockdep_sock_is_held(sk)) {
1079 if (key->family != family)
1080 continue;
1081 if (key->l3index && key->l3index != l3index)
1082 continue;
1083 if (!memcmp(&key->addr, addr, size) &&
1084 key->prefixlen == prefixlen)
1085 return key;
1086 }
1087 return NULL;
1088}
1089
1090struct tcp_md5sig_key *tcp_v4_md5_lookup(const struct sock *sk,
1091 const struct sock *addr_sk)
1092{
1093 const union tcp_md5_addr *addr;
1094 int l3index;
1095
1096 l3index = l3mdev_master_ifindex_by_index(sock_net(sk),
1097 addr_sk->sk_bound_dev_if);
1098 addr = (const union tcp_md5_addr *)&addr_sk->sk_daddr;
1099 return tcp_md5_do_lookup(sk, l3index, addr, AF_INET);
1100}
1101EXPORT_SYMBOL(tcp_v4_md5_lookup);
1102
1103/* This can be called on a newly created socket, from other files */
1104int tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr,
1105 int family, u8 prefixlen, int l3index,
1106 const u8 *newkey, u8 newkeylen, gfp_t gfp)
1107{
1108 /* Add Key to the list */
1109 struct tcp_md5sig_key *key;
1110 struct tcp_sock *tp = tcp_sk(sk);
1111 struct tcp_md5sig_info *md5sig;
1112
1113 key = tcp_md5_do_lookup_exact(sk, addr, family, prefixlen, l3index);
1114 if (key) {
1115 /* Pre-existing entry - just update that one.
1116 * Note that the key might be used concurrently.
1117 * data_race() is telling kcsan that we do not care of
1118 * key mismatches, since changing MD5 key on live flows
1119 * can lead to packet drops.
1120 */
1121 data_race(memcpy(key->key, newkey, newkeylen));
1122
1123 /* Pairs with READ_ONCE() in tcp_md5_hash_key().
1124 * Also note that a reader could catch new key->keylen value
1125 * but old key->key[], this is the reason we use __GFP_ZERO
1126 * at sock_kmalloc() time below these lines.
1127 */
1128 WRITE_ONCE(key->keylen, newkeylen);
1129
1130 return 0;
1131 }
1132
1133 md5sig = rcu_dereference_protected(tp->md5sig_info,
1134 lockdep_sock_is_held(sk));
1135 if (!md5sig) {
1136 md5sig = kmalloc(sizeof(*md5sig), gfp);
1137 if (!md5sig)
1138 return -ENOMEM;
1139
1140 sk_nocaps_add(sk, NETIF_F_GSO_MASK);
1141 INIT_HLIST_HEAD(&md5sig->head);
1142 rcu_assign_pointer(tp->md5sig_info, md5sig);
1143 }
1144
1145 key = sock_kmalloc(sk, sizeof(*key), gfp | __GFP_ZERO);
1146 if (!key)
1147 return -ENOMEM;
1148 if (!tcp_alloc_md5sig_pool()) {
1149 sock_kfree_s(sk, key, sizeof(*key));
1150 return -ENOMEM;
1151 }
1152
1153 memcpy(key->key, newkey, newkeylen);
1154 key->keylen = newkeylen;
1155 key->family = family;
1156 key->prefixlen = prefixlen;
1157 key->l3index = l3index;
1158 memcpy(&key->addr, addr,
1159 (family == AF_INET6) ? sizeof(struct in6_addr) :
1160 sizeof(struct in_addr));
1161 hlist_add_head_rcu(&key->node, &md5sig->head);
1162 return 0;
1163}
1164EXPORT_SYMBOL(tcp_md5_do_add);
1165
1166int tcp_md5_do_del(struct sock *sk, const union tcp_md5_addr *addr, int family,
1167 u8 prefixlen, int l3index)
1168{
1169 struct tcp_md5sig_key *key;
1170
1171 key = tcp_md5_do_lookup_exact(sk, addr, family, prefixlen, l3index);
1172 if (!key)
1173 return -ENOENT;
1174 hlist_del_rcu(&key->node);
1175 atomic_sub(sizeof(*key), &sk->sk_omem_alloc);
1176 kfree_rcu(key, rcu);
1177 return 0;
1178}
1179EXPORT_SYMBOL(tcp_md5_do_del);
1180
1181static void tcp_clear_md5_list(struct sock *sk)
1182{
1183 struct tcp_sock *tp = tcp_sk(sk);
1184 struct tcp_md5sig_key *key;
1185 struct hlist_node *n;
1186 struct tcp_md5sig_info *md5sig;
1187
1188 md5sig = rcu_dereference_protected(tp->md5sig_info, 1);
1189
1190 hlist_for_each_entry_safe(key, n, &md5sig->head, node) {
1191 hlist_del_rcu(&key->node);
1192 atomic_sub(sizeof(*key), &sk->sk_omem_alloc);
1193 kfree_rcu(key, rcu);
1194 }
1195}
1196
1197static int tcp_v4_parse_md5_keys(struct sock *sk, int optname,
1198 sockptr_t optval, int optlen)
1199{
1200 struct tcp_md5sig cmd;
1201 struct sockaddr_in *sin = (struct sockaddr_in *)&cmd.tcpm_addr;
1202 const union tcp_md5_addr *addr;
1203 u8 prefixlen = 32;
1204 int l3index = 0;
1205
1206 if (optlen < sizeof(cmd))
1207 return -EINVAL;
1208
1209 if (copy_from_sockptr(&cmd, optval, sizeof(cmd)))
1210 return -EFAULT;
1211
1212 if (sin->sin_family != AF_INET)
1213 return -EINVAL;
1214
1215 if (optname == TCP_MD5SIG_EXT &&
1216 cmd.tcpm_flags & TCP_MD5SIG_FLAG_PREFIX) {
1217 prefixlen = cmd.tcpm_prefixlen;
1218 if (prefixlen > 32)
1219 return -EINVAL;
1220 }
1221
1222 if (optname == TCP_MD5SIG_EXT &&
1223 cmd.tcpm_flags & TCP_MD5SIG_FLAG_IFINDEX) {
1224 struct net_device *dev;
1225
1226 rcu_read_lock();
1227 dev = dev_get_by_index_rcu(sock_net(sk), cmd.tcpm_ifindex);
1228 if (dev && netif_is_l3_master(dev))
1229 l3index = dev->ifindex;
1230
1231 rcu_read_unlock();
1232
1233 /* ok to reference set/not set outside of rcu;
1234 * right now device MUST be an L3 master
1235 */
1236 if (!dev || !l3index)
1237 return -EINVAL;
1238 }
1239
1240 addr = (union tcp_md5_addr *)&sin->sin_addr.s_addr;
1241
1242 if (!cmd.tcpm_keylen)
1243 return tcp_md5_do_del(sk, addr, AF_INET, prefixlen, l3index);
1244
1245 if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN)
1246 return -EINVAL;
1247
1248 return tcp_md5_do_add(sk, addr, AF_INET, prefixlen, l3index,
1249 cmd.tcpm_key, cmd.tcpm_keylen, GFP_KERNEL);
1250}
1251
1252static int tcp_v4_md5_hash_headers(struct tcp_md5sig_pool *hp,
1253 __be32 daddr, __be32 saddr,
1254 const struct tcphdr *th, int nbytes)
1255{
1256 struct tcp4_pseudohdr *bp;
1257 struct scatterlist sg;
1258 struct tcphdr *_th;
1259
1260 bp = hp->scratch;
1261 bp->saddr = saddr;
1262 bp->daddr = daddr;
1263 bp->pad = 0;
1264 bp->protocol = IPPROTO_TCP;
1265 bp->len = cpu_to_be16(nbytes);
1266
1267 _th = (struct tcphdr *)(bp + 1);
1268 memcpy(_th, th, sizeof(*th));
1269 _th->check = 0;
1270
1271 sg_init_one(&sg, bp, sizeof(*bp) + sizeof(*th));
1272 ahash_request_set_crypt(hp->md5_req, &sg, NULL,
1273 sizeof(*bp) + sizeof(*th));
1274 return crypto_ahash_update(hp->md5_req);
1275}
1276
1277static int tcp_v4_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key,
1278 __be32 daddr, __be32 saddr, const struct tcphdr *th)
1279{
1280 struct tcp_md5sig_pool *hp;
1281 struct ahash_request *req;
1282
1283 hp = tcp_get_md5sig_pool();
1284 if (!hp)
1285 goto clear_hash_noput;
1286 req = hp->md5_req;
1287
1288 if (crypto_ahash_init(req))
1289 goto clear_hash;
1290 if (tcp_v4_md5_hash_headers(hp, daddr, saddr, th, th->doff << 2))
1291 goto clear_hash;
1292 if (tcp_md5_hash_key(hp, key))
1293 goto clear_hash;
1294 ahash_request_set_crypt(req, NULL, md5_hash, 0);
1295 if (crypto_ahash_final(req))
1296 goto clear_hash;
1297
1298 tcp_put_md5sig_pool();
1299 return 0;
1300
1301clear_hash:
1302 tcp_put_md5sig_pool();
1303clear_hash_noput:
1304 memset(md5_hash, 0, 16);
1305 return 1;
1306}
1307
1308int tcp_v4_md5_hash_skb(char *md5_hash, const struct tcp_md5sig_key *key,
1309 const struct sock *sk,
1310 const struct sk_buff *skb)
1311{
1312 struct tcp_md5sig_pool *hp;
1313 struct ahash_request *req;
1314 const struct tcphdr *th = tcp_hdr(skb);
1315 __be32 saddr, daddr;
1316
1317 if (sk) { /* valid for establish/request sockets */
1318 saddr = sk->sk_rcv_saddr;
1319 daddr = sk->sk_daddr;
1320 } else {
1321 const struct iphdr *iph = ip_hdr(skb);
1322 saddr = iph->saddr;
1323 daddr = iph->daddr;
1324 }
1325
1326 hp = tcp_get_md5sig_pool();
1327 if (!hp)
1328 goto clear_hash_noput;
1329 req = hp->md5_req;
1330
1331 if (crypto_ahash_init(req))
1332 goto clear_hash;
1333
1334 if (tcp_v4_md5_hash_headers(hp, daddr, saddr, th, skb->len))
1335 goto clear_hash;
1336 if (tcp_md5_hash_skb_data(hp, skb, th->doff << 2))
1337 goto clear_hash;
1338 if (tcp_md5_hash_key(hp, key))
1339 goto clear_hash;
1340 ahash_request_set_crypt(req, NULL, md5_hash, 0);
1341 if (crypto_ahash_final(req))
1342 goto clear_hash;
1343
1344 tcp_put_md5sig_pool();
1345 return 0;
1346
1347clear_hash:
1348 tcp_put_md5sig_pool();
1349clear_hash_noput:
1350 memset(md5_hash, 0, 16);
1351 return 1;
1352}
1353EXPORT_SYMBOL(tcp_v4_md5_hash_skb);
1354
1355#endif
1356
1357/* Called with rcu_read_lock() */
1358static bool tcp_v4_inbound_md5_hash(const struct sock *sk,
1359 const struct sk_buff *skb,
1360 int dif, int sdif)
1361{
1362#ifdef CONFIG_TCP_MD5SIG
1363 /*
1364 * This gets called for each TCP segment that arrives
1365 * so we want to be efficient.
1366 * We have 3 drop cases:
1367 * o No MD5 hash and one expected.
1368 * o MD5 hash and we're not expecting one.
1369 * o MD5 hash and its wrong.
1370 */
1371 const __u8 *hash_location = NULL;
1372 struct tcp_md5sig_key *hash_expected;
1373 const struct iphdr *iph = ip_hdr(skb);
1374 const struct tcphdr *th = tcp_hdr(skb);
1375 const union tcp_md5_addr *addr;
1376 unsigned char newhash[16];
1377 int genhash, l3index;
1378
1379 /* sdif set, means packet ingressed via a device
1380 * in an L3 domain and dif is set to the l3mdev
1381 */
1382 l3index = sdif ? dif : 0;
1383
1384 addr = (union tcp_md5_addr *)&iph->saddr;
1385 hash_expected = tcp_md5_do_lookup(sk, l3index, addr, AF_INET);
1386 hash_location = tcp_parse_md5sig_option(th);
1387
1388 /* We've parsed the options - do we have a hash? */
1389 if (!hash_expected && !hash_location)
1390 return false;
1391
1392 if (hash_expected && !hash_location) {
1393 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5NOTFOUND);
1394 return true;
1395 }
1396
1397 if (!hash_expected && hash_location) {
1398 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5UNEXPECTED);
1399 return true;
1400 }
1401
1402 /* Okay, so this is hash_expected and hash_location -
1403 * so we need to calculate the checksum.
1404 */
1405 genhash = tcp_v4_md5_hash_skb(newhash,
1406 hash_expected,
1407 NULL, skb);
1408
1409 if (genhash || memcmp(hash_location, newhash, 16) != 0) {
1410 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5FAILURE);
1411 net_info_ratelimited("MD5 Hash failed for (%pI4, %d)->(%pI4, %d)%s L3 index %d\n",
1412 &iph->saddr, ntohs(th->source),
1413 &iph->daddr, ntohs(th->dest),
1414 genhash ? " tcp_v4_calc_md5_hash failed"
1415 : "", l3index);
1416 return true;
1417 }
1418 return false;
1419#endif
1420 return false;
1421}
1422
1423static void tcp_v4_init_req(struct request_sock *req,
1424 const struct sock *sk_listener,
1425 struct sk_buff *skb)
1426{
1427 struct inet_request_sock *ireq = inet_rsk(req);
1428 struct net *net = sock_net(sk_listener);
1429
1430 sk_rcv_saddr_set(req_to_sk(req), ip_hdr(skb)->daddr);
1431 sk_daddr_set(req_to_sk(req), ip_hdr(skb)->saddr);
1432 RCU_INIT_POINTER(ireq->ireq_opt, tcp_v4_save_options(net, skb));
1433}
1434
1435static struct dst_entry *tcp_v4_route_req(const struct sock *sk,
1436 struct flowi *fl,
1437 const struct request_sock *req)
1438{
1439 return inet_csk_route_req(sk, &fl->u.ip4, req);
1440}
1441
1442struct request_sock_ops tcp_request_sock_ops __read_mostly = {
1443 .family = PF_INET,
1444 .obj_size = sizeof(struct tcp_request_sock),
1445 .rtx_syn_ack = tcp_rtx_synack,
1446 .send_ack = tcp_v4_reqsk_send_ack,
1447 .destructor = tcp_v4_reqsk_destructor,
1448 .send_reset = tcp_v4_send_reset,
1449 .syn_ack_timeout = tcp_syn_ack_timeout,
1450};
1451
1452const struct tcp_request_sock_ops tcp_request_sock_ipv4_ops = {
1453 .mss_clamp = TCP_MSS_DEFAULT,
1454#ifdef CONFIG_TCP_MD5SIG
1455 .req_md5_lookup = tcp_v4_md5_lookup,
1456 .calc_md5_hash = tcp_v4_md5_hash_skb,
1457#endif
1458 .init_req = tcp_v4_init_req,
1459#ifdef CONFIG_SYN_COOKIES
1460 .cookie_init_seq = cookie_v4_init_sequence,
1461#endif
1462 .route_req = tcp_v4_route_req,
1463 .init_seq = tcp_v4_init_seq,
1464 .init_ts_off = tcp_v4_init_ts_off,
1465 .send_synack = tcp_v4_send_synack,
1466};
1467
1468int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
1469{
1470 /* Never answer to SYNs send to broadcast or multicast */
1471 if (skb_rtable(skb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
1472 goto drop;
1473
1474 return tcp_conn_request(&tcp_request_sock_ops,
1475 &tcp_request_sock_ipv4_ops, sk, skb);
1476
1477drop:
1478 tcp_listendrop(sk);
1479 return 0;
1480}
1481EXPORT_SYMBOL(tcp_v4_conn_request);
1482
1483
1484/*
1485 * The three way handshake has completed - we got a valid synack -
1486 * now create the new socket.
1487 */
1488struct sock *tcp_v4_syn_recv_sock(const struct sock *sk, struct sk_buff *skb,
1489 struct request_sock *req,
1490 struct dst_entry *dst,
1491 struct request_sock *req_unhash,
1492 bool *own_req)
1493{
1494 struct inet_request_sock *ireq;
1495 struct inet_sock *newinet;
1496 struct tcp_sock *newtp;
1497 struct sock *newsk;
1498#ifdef CONFIG_TCP_MD5SIG
1499 const union tcp_md5_addr *addr;
1500 struct tcp_md5sig_key *key;
1501 int l3index;
1502#endif
1503 struct ip_options_rcu *inet_opt;
1504
1505 if (sk_acceptq_is_full(sk))
1506 goto exit_overflow;
1507
1508 newsk = tcp_create_openreq_child(sk, req, skb);
1509 if (!newsk)
1510 goto exit_nonewsk;
1511
1512 newsk->sk_gso_type = SKB_GSO_TCPV4;
1513 inet_sk_rx_dst_set(newsk, skb);
1514
1515 newtp = tcp_sk(newsk);
1516 newinet = inet_sk(newsk);
1517 ireq = inet_rsk(req);
1518 sk_daddr_set(newsk, ireq->ir_rmt_addr);
1519 sk_rcv_saddr_set(newsk, ireq->ir_loc_addr);
1520 newsk->sk_bound_dev_if = ireq->ir_iif;
1521 newinet->inet_saddr = ireq->ir_loc_addr;
1522 inet_opt = rcu_dereference(ireq->ireq_opt);
1523 RCU_INIT_POINTER(newinet->inet_opt, inet_opt);
1524 newinet->mc_index = inet_iif(skb);
1525 newinet->mc_ttl = ip_hdr(skb)->ttl;
1526 newinet->rcv_tos = ip_hdr(skb)->tos;
1527 inet_csk(newsk)->icsk_ext_hdr_len = 0;
1528 if (inet_opt)
1529 inet_csk(newsk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
1530 newinet->inet_id = prandom_u32();
1531
1532 if (!dst) {
1533 dst = inet_csk_route_child_sock(sk, newsk, req);
1534 if (!dst)
1535 goto put_and_exit;
1536 } else {
1537 /* syncookie case : see end of cookie_v4_check() */
1538 }
1539 sk_setup_caps(newsk, dst);
1540
1541 tcp_ca_openreq_child(newsk, dst);
1542
1543 tcp_sync_mss(newsk, dst_mtu(dst));
1544 newtp->advmss = tcp_mss_clamp(tcp_sk(sk), dst_metric_advmss(dst));
1545
1546 tcp_initialize_rcv_mss(newsk);
1547
1548#ifdef CONFIG_TCP_MD5SIG
1549 l3index = l3mdev_master_ifindex_by_index(sock_net(sk), ireq->ir_iif);
1550 /* Copy over the MD5 key from the original socket */
1551 addr = (union tcp_md5_addr *)&newinet->inet_daddr;
1552 key = tcp_md5_do_lookup(sk, l3index, addr, AF_INET);
1553 if (key) {
1554 /*
1555 * We're using one, so create a matching key
1556 * on the newsk structure. If we fail to get
1557 * memory, then we end up not copying the key
1558 * across. Shucks.
1559 */
1560 tcp_md5_do_add(newsk, addr, AF_INET, 32, l3index,
1561 key->key, key->keylen, GFP_ATOMIC);
1562 sk_nocaps_add(newsk, NETIF_F_GSO_MASK);
1563 }
1564#endif
1565
1566 if (__inet_inherit_port(sk, newsk) < 0)
1567 goto put_and_exit;
1568 *own_req = inet_ehash_nolisten(newsk, req_to_sk(req_unhash));
1569 if (likely(*own_req)) {
1570 tcp_move_syn(newtp, req);
1571 ireq->ireq_opt = NULL;
1572 } else {
1573 newinet->inet_opt = NULL;
1574 }
1575 return newsk;
1576
1577exit_overflow:
1578 NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
1579exit_nonewsk:
1580 dst_release(dst);
1581exit:
1582 tcp_listendrop(sk);
1583 return NULL;
1584put_and_exit:
1585 newinet->inet_opt = NULL;
1586 inet_csk_prepare_forced_close(newsk);
1587 tcp_done(newsk);
1588 goto exit;
1589}
1590EXPORT_SYMBOL(tcp_v4_syn_recv_sock);
1591
1592static struct sock *tcp_v4_cookie_check(struct sock *sk, struct sk_buff *skb)
1593{
1594#ifdef CONFIG_SYN_COOKIES
1595 const struct tcphdr *th = tcp_hdr(skb);
1596
1597 if (!th->syn)
1598 sk = cookie_v4_check(sk, skb);
1599#endif
1600 return sk;
1601}
1602
1603u16 tcp_v4_get_syncookie(struct sock *sk, struct iphdr *iph,
1604 struct tcphdr *th, u32 *cookie)
1605{
1606 u16 mss = 0;
1607#ifdef CONFIG_SYN_COOKIES
1608 mss = tcp_get_syncookie_mss(&tcp_request_sock_ops,
1609 &tcp_request_sock_ipv4_ops, sk, th);
1610 if (mss) {
1611 *cookie = __cookie_v4_init_sequence(iph, th, &mss);
1612 tcp_synq_overflow(sk);
1613 }
1614#endif
1615 return mss;
1616}
1617
1618/* The socket must have it's spinlock held when we get
1619 * here, unless it is a TCP_LISTEN socket.
1620 *
1621 * We have a potential double-lock case here, so even when
1622 * doing backlog processing we use the BH locking scheme.
1623 * This is because we cannot sleep with the original spinlock
1624 * held.
1625 */
1626int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
1627{
1628 struct sock *rsk;
1629
1630 if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
1631 struct dst_entry *dst = sk->sk_rx_dst;
1632
1633 sock_rps_save_rxhash(sk, skb);
1634 sk_mark_napi_id(sk, skb);
1635 if (dst) {
1636 if (inet_sk(sk)->rx_dst_ifindex != skb->skb_iif ||
1637 !dst->ops->check(dst, 0)) {
1638 dst_release(dst);
1639 sk->sk_rx_dst = NULL;
1640 }
1641 }
1642 tcp_rcv_established(sk, skb);
1643 return 0;
1644 }
1645
1646 if (tcp_checksum_complete(skb))
1647 goto csum_err;
1648
1649 if (sk->sk_state == TCP_LISTEN) {
1650 struct sock *nsk = tcp_v4_cookie_check(sk, skb);
1651
1652 if (!nsk)
1653 goto discard;
1654 if (nsk != sk) {
1655 if (tcp_child_process(sk, nsk, skb)) {
1656 rsk = nsk;
1657 goto reset;
1658 }
1659 return 0;
1660 }
1661 } else
1662 sock_rps_save_rxhash(sk, skb);
1663
1664 if (tcp_rcv_state_process(sk, skb)) {
1665 rsk = sk;
1666 goto reset;
1667 }
1668 return 0;
1669
1670reset:
1671 tcp_v4_send_reset(rsk, skb);
1672discard:
1673 kfree_skb(skb);
1674 /* Be careful here. If this function gets more complicated and
1675 * gcc suffers from register pressure on the x86, sk (in %ebx)
1676 * might be destroyed here. This current version compiles correctly,
1677 * but you have been warned.
1678 */
1679 return 0;
1680
1681csum_err:
1682 TCP_INC_STATS(sock_net(sk), TCP_MIB_CSUMERRORS);
1683 TCP_INC_STATS(sock_net(sk), TCP_MIB_INERRS);
1684 goto discard;
1685}
1686EXPORT_SYMBOL(tcp_v4_do_rcv);
1687
1688int tcp_v4_early_demux(struct sk_buff *skb)
1689{
1690 const struct iphdr *iph;
1691 const struct tcphdr *th;
1692 struct sock *sk;
1693
1694 if (skb->pkt_type != PACKET_HOST)
1695 return 0;
1696
1697 if (!pskb_may_pull(skb, skb_transport_offset(skb) + sizeof(struct tcphdr)))
1698 return 0;
1699
1700 iph = ip_hdr(skb);
1701 th = tcp_hdr(skb);
1702
1703 if (th->doff < sizeof(struct tcphdr) / 4)
1704 return 0;
1705
1706 sk = __inet_lookup_established(dev_net(skb->dev), &tcp_hashinfo,
1707 iph->saddr, th->source,
1708 iph->daddr, ntohs(th->dest),
1709 skb->skb_iif, inet_sdif(skb));
1710 if (sk) {
1711 skb->sk = sk;
1712 skb->destructor = sock_edemux;
1713 if (sk_fullsock(sk)) {
1714 struct dst_entry *dst = READ_ONCE(sk->sk_rx_dst);
1715
1716 if (dst)
1717 dst = dst_check(dst, 0);
1718 if (dst &&
1719 inet_sk(sk)->rx_dst_ifindex == skb->skb_iif)
1720 skb_dst_set_noref(skb, dst);
1721 }
1722 }
1723 return 0;
1724}
1725
1726bool tcp_add_backlog(struct sock *sk, struct sk_buff *skb)
1727{
1728 u32 limit = READ_ONCE(sk->sk_rcvbuf) + READ_ONCE(sk->sk_sndbuf);
1729 struct skb_shared_info *shinfo;
1730 const struct tcphdr *th;
1731 struct tcphdr *thtail;
1732 struct sk_buff *tail;
1733 unsigned int hdrlen;
1734 bool fragstolen;
1735 u32 gso_segs;
1736 int delta;
1737
1738 /* In case all data was pulled from skb frags (in __pskb_pull_tail()),
1739 * we can fix skb->truesize to its real value to avoid future drops.
1740 * This is valid because skb is not yet charged to the socket.
1741 * It has been noticed pure SACK packets were sometimes dropped
1742 * (if cooked by drivers without copybreak feature).
1743 */
1744 skb_condense(skb);
1745
1746 skb_dst_drop(skb);
1747
1748 if (unlikely(tcp_checksum_complete(skb))) {
1749 bh_unlock_sock(sk);
1750 __TCP_INC_STATS(sock_net(sk), TCP_MIB_CSUMERRORS);
1751 __TCP_INC_STATS(sock_net(sk), TCP_MIB_INERRS);
1752 return true;
1753 }
1754
1755 /* Attempt coalescing to last skb in backlog, even if we are
1756 * above the limits.
1757 * This is okay because skb capacity is limited to MAX_SKB_FRAGS.
1758 */
1759 th = (const struct tcphdr *)skb->data;
1760 hdrlen = th->doff * 4;
1761 shinfo = skb_shinfo(skb);
1762
1763 if (!shinfo->gso_size)
1764 shinfo->gso_size = skb->len - hdrlen;
1765
1766 if (!shinfo->gso_segs)
1767 shinfo->gso_segs = 1;
1768
1769 tail = sk->sk_backlog.tail;
1770 if (!tail)
1771 goto no_coalesce;
1772 thtail = (struct tcphdr *)tail->data;
1773
1774 if (TCP_SKB_CB(tail)->end_seq != TCP_SKB_CB(skb)->seq ||
1775 TCP_SKB_CB(tail)->ip_dsfield != TCP_SKB_CB(skb)->ip_dsfield ||
1776 ((TCP_SKB_CB(tail)->tcp_flags |
1777 TCP_SKB_CB(skb)->tcp_flags) & (TCPHDR_SYN | TCPHDR_RST | TCPHDR_URG)) ||
1778 !((TCP_SKB_CB(tail)->tcp_flags &
1779 TCP_SKB_CB(skb)->tcp_flags) & TCPHDR_ACK) ||
1780 ((TCP_SKB_CB(tail)->tcp_flags ^
1781 TCP_SKB_CB(skb)->tcp_flags) & (TCPHDR_ECE | TCPHDR_CWR)) ||
1782#ifdef CONFIG_TLS_DEVICE
1783 tail->decrypted != skb->decrypted ||
1784#endif
1785 thtail->doff != th->doff ||
1786 memcmp(thtail + 1, th + 1, hdrlen - sizeof(*th)))
1787 goto no_coalesce;
1788
1789 __skb_pull(skb, hdrlen);
1790 if (skb_try_coalesce(tail, skb, &fragstolen, &delta)) {
1791 TCP_SKB_CB(tail)->end_seq = TCP_SKB_CB(skb)->end_seq;
1792
1793 if (likely(!before(TCP_SKB_CB(skb)->ack_seq, TCP_SKB_CB(tail)->ack_seq))) {
1794 TCP_SKB_CB(tail)->ack_seq = TCP_SKB_CB(skb)->ack_seq;
1795 thtail->window = th->window;
1796 }
1797
1798 /* We have to update both TCP_SKB_CB(tail)->tcp_flags and
1799 * thtail->fin, so that the fast path in tcp_rcv_established()
1800 * is not entered if we append a packet with a FIN.
1801 * SYN, RST, URG are not present.
1802 * ACK is set on both packets.
1803 * PSH : we do not really care in TCP stack,
1804 * at least for 'GRO' packets.
1805 */
1806 thtail->fin |= th->fin;
1807 TCP_SKB_CB(tail)->tcp_flags |= TCP_SKB_CB(skb)->tcp_flags;
1808
1809 if (TCP_SKB_CB(skb)->has_rxtstamp) {
1810 TCP_SKB_CB(tail)->has_rxtstamp = true;
1811 tail->tstamp = skb->tstamp;
1812 skb_hwtstamps(tail)->hwtstamp = skb_hwtstamps(skb)->hwtstamp;
1813 }
1814
1815 /* Not as strict as GRO. We only need to carry mss max value */
1816 skb_shinfo(tail)->gso_size = max(shinfo->gso_size,
1817 skb_shinfo(tail)->gso_size);
1818
1819 gso_segs = skb_shinfo(tail)->gso_segs + shinfo->gso_segs;
1820 skb_shinfo(tail)->gso_segs = min_t(u32, gso_segs, 0xFFFF);
1821
1822 sk->sk_backlog.len += delta;
1823 __NET_INC_STATS(sock_net(sk),
1824 LINUX_MIB_TCPBACKLOGCOALESCE);
1825 kfree_skb_partial(skb, fragstolen);
1826 return false;
1827 }
1828 __skb_push(skb, hdrlen);
1829
1830no_coalesce:
1831 /* Only socket owner can try to collapse/prune rx queues
1832 * to reduce memory overhead, so add a little headroom here.
1833 * Few sockets backlog are possibly concurrently non empty.
1834 */
1835 limit += 64*1024;
1836
1837 if (unlikely(sk_add_backlog(sk, skb, limit))) {
1838 bh_unlock_sock(sk);
1839 __NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPBACKLOGDROP);
1840 return true;
1841 }
1842 return false;
1843}
1844EXPORT_SYMBOL(tcp_add_backlog);
1845
1846int tcp_filter(struct sock *sk, struct sk_buff *skb)
1847{
1848 struct tcphdr *th = (struct tcphdr *)skb->data;
1849
1850 return sk_filter_trim_cap(sk, skb, th->doff * 4);
1851}
1852EXPORT_SYMBOL(tcp_filter);
1853
1854static void tcp_v4_restore_cb(struct sk_buff *skb)
1855{
1856 memmove(IPCB(skb), &TCP_SKB_CB(skb)->header.h4,
1857 sizeof(struct inet_skb_parm));
1858}
1859
1860static void tcp_v4_fill_cb(struct sk_buff *skb, const struct iphdr *iph,
1861 const struct tcphdr *th)
1862{
1863 /* This is tricky : We move IPCB at its correct location into TCP_SKB_CB()
1864 * barrier() makes sure compiler wont play fool^Waliasing games.
1865 */
1866 memmove(&TCP_SKB_CB(skb)->header.h4, IPCB(skb),
1867 sizeof(struct inet_skb_parm));
1868 barrier();
1869
1870 TCP_SKB_CB(skb)->seq = ntohl(th->seq);
1871 TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
1872 skb->len - th->doff * 4);
1873 TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
1874 TCP_SKB_CB(skb)->tcp_flags = tcp_flag_byte(th);
1875 TCP_SKB_CB(skb)->tcp_tw_isn = 0;
1876 TCP_SKB_CB(skb)->ip_dsfield = ipv4_get_dsfield(iph);
1877 TCP_SKB_CB(skb)->sacked = 0;
1878 TCP_SKB_CB(skb)->has_rxtstamp =
1879 skb->tstamp || skb_hwtstamps(skb)->hwtstamp;
1880}
1881
1882/*
1883 * From tcp_input.c
1884 */
1885
1886int tcp_v4_rcv(struct sk_buff *skb)
1887{
1888 struct net *net = dev_net(skb->dev);
1889 struct sk_buff *skb_to_free;
1890 int sdif = inet_sdif(skb);
1891 int dif = inet_iif(skb);
1892 const struct iphdr *iph;
1893 const struct tcphdr *th;
1894 bool refcounted;
1895 struct sock *sk;
1896 int ret;
1897
1898 if (skb->pkt_type != PACKET_HOST)
1899 goto discard_it;
1900
1901 /* Count it even if it's bad */
1902 __TCP_INC_STATS(net, TCP_MIB_INSEGS);
1903
1904 if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
1905 goto discard_it;
1906
1907 th = (const struct tcphdr *)skb->data;
1908
1909 if (unlikely(th->doff < sizeof(struct tcphdr) / 4))
1910 goto bad_packet;
1911 if (!pskb_may_pull(skb, th->doff * 4))
1912 goto discard_it;
1913
1914 /* An explanation is required here, I think.
1915 * Packet length and doff are validated by header prediction,
1916 * provided case of th->doff==0 is eliminated.
1917 * So, we defer the checks. */
1918
1919 if (skb_checksum_init(skb, IPPROTO_TCP, inet_compute_pseudo))
1920 goto csum_error;
1921
1922 th = (const struct tcphdr *)skb->data;
1923 iph = ip_hdr(skb);
1924lookup:
1925 sk = __inet_lookup_skb(&tcp_hashinfo, skb, __tcp_hdrlen(th), th->source,
1926 th->dest, sdif, &refcounted);
1927 if (!sk)
1928 goto no_tcp_socket;
1929
1930process:
1931 if (sk->sk_state == TCP_TIME_WAIT)
1932 goto do_time_wait;
1933
1934 if (sk->sk_state == TCP_NEW_SYN_RECV) {
1935 struct request_sock *req = inet_reqsk(sk);
1936 bool req_stolen = false;
1937 struct sock *nsk;
1938
1939 sk = req->rsk_listener;
1940 if (unlikely(tcp_v4_inbound_md5_hash(sk, skb, dif, sdif))) {
1941 sk_drops_add(sk, skb);
1942 reqsk_put(req);
1943 goto discard_it;
1944 }
1945 if (tcp_checksum_complete(skb)) {
1946 reqsk_put(req);
1947 goto csum_error;
1948 }
1949 if (unlikely(sk->sk_state != TCP_LISTEN)) {
1950 inet_csk_reqsk_queue_drop_and_put(sk, req);
1951 goto lookup;
1952 }
1953 /* We own a reference on the listener, increase it again
1954 * as we might lose it too soon.
1955 */
1956 sock_hold(sk);
1957 refcounted = true;
1958 nsk = NULL;
1959 if (!tcp_filter(sk, skb)) {
1960 th = (const struct tcphdr *)skb->data;
1961 iph = ip_hdr(skb);
1962 tcp_v4_fill_cb(skb, iph, th);
1963 nsk = tcp_check_req(sk, skb, req, false, &req_stolen);
1964 }
1965 if (!nsk) {
1966 reqsk_put(req);
1967 if (req_stolen) {
1968 /* Another cpu got exclusive access to req
1969 * and created a full blown socket.
1970 * Try to feed this packet to this socket
1971 * instead of discarding it.
1972 */
1973 tcp_v4_restore_cb(skb);
1974 sock_put(sk);
1975 goto lookup;
1976 }
1977 goto discard_and_relse;
1978 }
1979 if (nsk == sk) {
1980 reqsk_put(req);
1981 tcp_v4_restore_cb(skb);
1982 } else if (tcp_child_process(sk, nsk, skb)) {
1983 tcp_v4_send_reset(nsk, skb);
1984 goto discard_and_relse;
1985 } else {
1986 sock_put(sk);
1987 return 0;
1988 }
1989 }
1990 if (unlikely(iph->ttl < inet_sk(sk)->min_ttl)) {
1991 __NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP);
1992 goto discard_and_relse;
1993 }
1994
1995 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
1996 goto discard_and_relse;
1997
1998 if (tcp_v4_inbound_md5_hash(sk, skb, dif, sdif))
1999 goto discard_and_relse;
2000
2001 nf_reset_ct(skb);
2002
2003 if (tcp_filter(sk, skb))
2004 goto discard_and_relse;
2005 th = (const struct tcphdr *)skb->data;
2006 iph = ip_hdr(skb);
2007 tcp_v4_fill_cb(skb, iph, th);
2008
2009 skb->dev = NULL;
2010
2011 if (sk->sk_state == TCP_LISTEN) {
2012 ret = tcp_v4_do_rcv(sk, skb);
2013 goto put_and_return;
2014 }
2015
2016 sk_incoming_cpu_update(sk);
2017
2018 bh_lock_sock_nested(sk);
2019 tcp_segs_in(tcp_sk(sk), skb);
2020 ret = 0;
2021 if (!sock_owned_by_user(sk)) {
2022 skb_to_free = sk->sk_rx_skb_cache;
2023 sk->sk_rx_skb_cache = NULL;
2024 ret = tcp_v4_do_rcv(sk, skb);
2025 } else {
2026 if (tcp_add_backlog(sk, skb))
2027 goto discard_and_relse;
2028 skb_to_free = NULL;
2029 }
2030 bh_unlock_sock(sk);
2031 if (skb_to_free)
2032 __kfree_skb(skb_to_free);
2033
2034put_and_return:
2035 if (refcounted)
2036 sock_put(sk);
2037
2038 return ret;
2039
2040no_tcp_socket:
2041 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
2042 goto discard_it;
2043
2044 tcp_v4_fill_cb(skb, iph, th);
2045
2046 if (tcp_checksum_complete(skb)) {
2047csum_error:
2048 __TCP_INC_STATS(net, TCP_MIB_CSUMERRORS);
2049bad_packet:
2050 __TCP_INC_STATS(net, TCP_MIB_INERRS);
2051 } else {
2052 tcp_v4_send_reset(NULL, skb);
2053 }
2054
2055discard_it:
2056 /* Discard frame. */
2057 kfree_skb(skb);
2058 return 0;
2059
2060discard_and_relse:
2061 sk_drops_add(sk, skb);
2062 if (refcounted)
2063 sock_put(sk);
2064 goto discard_it;
2065
2066do_time_wait:
2067 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
2068 inet_twsk_put(inet_twsk(sk));
2069 goto discard_it;
2070 }
2071
2072 tcp_v4_fill_cb(skb, iph, th);
2073
2074 if (tcp_checksum_complete(skb)) {
2075 inet_twsk_put(inet_twsk(sk));
2076 goto csum_error;
2077 }
2078 switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) {
2079 case TCP_TW_SYN: {
2080 struct sock *sk2 = inet_lookup_listener(dev_net(skb->dev),
2081 &tcp_hashinfo, skb,
2082 __tcp_hdrlen(th),
2083 iph->saddr, th->source,
2084 iph->daddr, th->dest,
2085 inet_iif(skb),
2086 sdif);
2087 if (sk2) {
2088 inet_twsk_deschedule_put(inet_twsk(sk));
2089 sk = sk2;
2090 tcp_v4_restore_cb(skb);
2091 refcounted = false;
2092 goto process;
2093 }
2094 }
2095 /* to ACK */
2096 fallthrough;
2097 case TCP_TW_ACK:
2098 tcp_v4_timewait_ack(sk, skb);
2099 break;
2100 case TCP_TW_RST:
2101 tcp_v4_send_reset(sk, skb);
2102 inet_twsk_deschedule_put(inet_twsk(sk));
2103 goto discard_it;
2104 case TCP_TW_SUCCESS:;
2105 }
2106 goto discard_it;
2107}
2108
2109static struct timewait_sock_ops tcp_timewait_sock_ops = {
2110 .twsk_obj_size = sizeof(struct tcp_timewait_sock),
2111 .twsk_unique = tcp_twsk_unique,
2112 .twsk_destructor= tcp_twsk_destructor,
2113};
2114
2115void inet_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb)
2116{
2117 struct dst_entry *dst = skb_dst(skb);
2118
2119 if (dst && dst_hold_safe(dst)) {
2120 sk->sk_rx_dst = dst;
2121 inet_sk(sk)->rx_dst_ifindex = skb->skb_iif;
2122 }
2123}
2124EXPORT_SYMBOL(inet_sk_rx_dst_set);
2125
2126const struct inet_connection_sock_af_ops ipv4_specific = {
2127 .queue_xmit = ip_queue_xmit,
2128 .send_check = tcp_v4_send_check,
2129 .rebuild_header = inet_sk_rebuild_header,
2130 .sk_rx_dst_set = inet_sk_rx_dst_set,
2131 .conn_request = tcp_v4_conn_request,
2132 .syn_recv_sock = tcp_v4_syn_recv_sock,
2133 .net_header_len = sizeof(struct iphdr),
2134 .setsockopt = ip_setsockopt,
2135 .getsockopt = ip_getsockopt,
2136 .addr2sockaddr = inet_csk_addr2sockaddr,
2137 .sockaddr_len = sizeof(struct sockaddr_in),
2138 .mtu_reduced = tcp_v4_mtu_reduced,
2139};
2140EXPORT_SYMBOL(ipv4_specific);
2141
2142#ifdef CONFIG_TCP_MD5SIG
2143static const struct tcp_sock_af_ops tcp_sock_ipv4_specific = {
2144 .md5_lookup = tcp_v4_md5_lookup,
2145 .calc_md5_hash = tcp_v4_md5_hash_skb,
2146 .md5_parse = tcp_v4_parse_md5_keys,
2147};
2148#endif
2149
2150/* NOTE: A lot of things set to zero explicitly by call to
2151 * sk_alloc() so need not be done here.
2152 */
2153static int tcp_v4_init_sock(struct sock *sk)
2154{
2155 struct inet_connection_sock *icsk = inet_csk(sk);
2156
2157 tcp_init_sock(sk);
2158
2159 icsk->icsk_af_ops = &ipv4_specific;
2160
2161#ifdef CONFIG_TCP_MD5SIG
2162 tcp_sk(sk)->af_specific = &tcp_sock_ipv4_specific;
2163#endif
2164
2165 return 0;
2166}
2167
2168void tcp_v4_destroy_sock(struct sock *sk)
2169{
2170 struct tcp_sock *tp = tcp_sk(sk);
2171
2172 trace_tcp_destroy_sock(sk);
2173
2174 tcp_clear_xmit_timers(sk);
2175
2176 tcp_cleanup_congestion_control(sk);
2177
2178 tcp_cleanup_ulp(sk);
2179
2180 /* Cleanup up the write buffer. */
2181 tcp_write_queue_purge(sk);
2182
2183 /* Check if we want to disable active TFO */
2184 tcp_fastopen_active_disable_ofo_check(sk);
2185
2186 /* Cleans up our, hopefully empty, out_of_order_queue. */
2187 skb_rbtree_purge(&tp->out_of_order_queue);
2188
2189#ifdef CONFIG_TCP_MD5SIG
2190 /* Clean up the MD5 key list, if any */
2191 if (tp->md5sig_info) {
2192 tcp_clear_md5_list(sk);
2193 kfree_rcu(rcu_dereference_protected(tp->md5sig_info, 1), rcu);
2194 tp->md5sig_info = NULL;
2195 }
2196#endif
2197
2198 /* Clean up a referenced TCP bind bucket. */
2199 if (inet_csk(sk)->icsk_bind_hash)
2200 inet_put_port(sk);
2201
2202 BUG_ON(rcu_access_pointer(tp->fastopen_rsk));
2203
2204 /* If socket is aborted during connect operation */
2205 tcp_free_fastopen_req(tp);
2206 tcp_fastopen_destroy_cipher(sk);
2207 tcp_saved_syn_free(tp);
2208
2209 sk_sockets_allocated_dec(sk);
2210}
2211EXPORT_SYMBOL(tcp_v4_destroy_sock);
2212
2213#ifdef CONFIG_PROC_FS
2214/* Proc filesystem TCP sock list dumping. */
2215
2216/*
2217 * Get next listener socket follow cur. If cur is NULL, get first socket
2218 * starting from bucket given in st->bucket; when st->bucket is zero the
2219 * very first socket in the hash table is returned.
2220 */
2221static void *listening_get_next(struct seq_file *seq, void *cur)
2222{
2223 struct tcp_seq_afinfo *afinfo;
2224 struct tcp_iter_state *st = seq->private;
2225 struct net *net = seq_file_net(seq);
2226 struct inet_listen_hashbucket *ilb;
2227 struct hlist_nulls_node *node;
2228 struct sock *sk = cur;
2229
2230 if (st->bpf_seq_afinfo)
2231 afinfo = st->bpf_seq_afinfo;
2232 else
2233 afinfo = PDE_DATA(file_inode(seq->file));
2234
2235 if (!sk) {
2236get_head:
2237 ilb = &tcp_hashinfo.listening_hash[st->bucket];
2238 spin_lock(&ilb->lock);
2239 sk = sk_nulls_head(&ilb->nulls_head);
2240 st->offset = 0;
2241 goto get_sk;
2242 }
2243 ilb = &tcp_hashinfo.listening_hash[st->bucket];
2244 ++st->num;
2245 ++st->offset;
2246
2247 sk = sk_nulls_next(sk);
2248get_sk:
2249 sk_nulls_for_each_from(sk, node) {
2250 if (!net_eq(sock_net(sk), net))
2251 continue;
2252 if (afinfo->family == AF_UNSPEC ||
2253 sk->sk_family == afinfo->family)
2254 return sk;
2255 }
2256 spin_unlock(&ilb->lock);
2257 st->offset = 0;
2258 if (++st->bucket < INET_LHTABLE_SIZE)
2259 goto get_head;
2260 return NULL;
2261}
2262
2263static void *listening_get_idx(struct seq_file *seq, loff_t *pos)
2264{
2265 struct tcp_iter_state *st = seq->private;
2266 void *rc;
2267
2268 st->bucket = 0;
2269 st->offset = 0;
2270 rc = listening_get_next(seq, NULL);
2271
2272 while (rc && *pos) {
2273 rc = listening_get_next(seq, rc);
2274 --*pos;
2275 }
2276 return rc;
2277}
2278
2279static inline bool empty_bucket(const struct tcp_iter_state *st)
2280{
2281 return hlist_nulls_empty(&tcp_hashinfo.ehash[st->bucket].chain);
2282}
2283
2284/*
2285 * Get first established socket starting from bucket given in st->bucket.
2286 * If st->bucket is zero, the very first socket in the hash is returned.
2287 */
2288static void *established_get_first(struct seq_file *seq)
2289{
2290 struct tcp_seq_afinfo *afinfo;
2291 struct tcp_iter_state *st = seq->private;
2292 struct net *net = seq_file_net(seq);
2293 void *rc = NULL;
2294
2295 if (st->bpf_seq_afinfo)
2296 afinfo = st->bpf_seq_afinfo;
2297 else
2298 afinfo = PDE_DATA(file_inode(seq->file));
2299
2300 st->offset = 0;
2301 for (; st->bucket <= tcp_hashinfo.ehash_mask; ++st->bucket) {
2302 struct sock *sk;
2303 struct hlist_nulls_node *node;
2304 spinlock_t *lock = inet_ehash_lockp(&tcp_hashinfo, st->bucket);
2305
2306 /* Lockless fast path for the common case of empty buckets */
2307 if (empty_bucket(st))
2308 continue;
2309
2310 spin_lock_bh(lock);
2311 sk_nulls_for_each(sk, node, &tcp_hashinfo.ehash[st->bucket].chain) {
2312 if ((afinfo->family != AF_UNSPEC &&
2313 sk->sk_family != afinfo->family) ||
2314 !net_eq(sock_net(sk), net)) {
2315 continue;
2316 }
2317 rc = sk;
2318 goto out;
2319 }
2320 spin_unlock_bh(lock);
2321 }
2322out:
2323 return rc;
2324}
2325
2326static void *established_get_next(struct seq_file *seq, void *cur)
2327{
2328 struct tcp_seq_afinfo *afinfo;
2329 struct sock *sk = cur;
2330 struct hlist_nulls_node *node;
2331 struct tcp_iter_state *st = seq->private;
2332 struct net *net = seq_file_net(seq);
2333
2334 if (st->bpf_seq_afinfo)
2335 afinfo = st->bpf_seq_afinfo;
2336 else
2337 afinfo = PDE_DATA(file_inode(seq->file));
2338
2339 ++st->num;
2340 ++st->offset;
2341
2342 sk = sk_nulls_next(sk);
2343
2344 sk_nulls_for_each_from(sk, node) {
2345 if ((afinfo->family == AF_UNSPEC ||
2346 sk->sk_family == afinfo->family) &&
2347 net_eq(sock_net(sk), net))
2348 return sk;
2349 }
2350
2351 spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
2352 ++st->bucket;
2353 return established_get_first(seq);
2354}
2355
2356static void *established_get_idx(struct seq_file *seq, loff_t pos)
2357{
2358 struct tcp_iter_state *st = seq->private;
2359 void *rc;
2360
2361 st->bucket = 0;
2362 rc = established_get_first(seq);
2363
2364 while (rc && pos) {
2365 rc = established_get_next(seq, rc);
2366 --pos;
2367 }
2368 return rc;
2369}
2370
2371static void *tcp_get_idx(struct seq_file *seq, loff_t pos)
2372{
2373 void *rc;
2374 struct tcp_iter_state *st = seq->private;
2375
2376 st->state = TCP_SEQ_STATE_LISTENING;
2377 rc = listening_get_idx(seq, &pos);
2378
2379 if (!rc) {
2380 st->state = TCP_SEQ_STATE_ESTABLISHED;
2381 rc = established_get_idx(seq, pos);
2382 }
2383
2384 return rc;
2385}
2386
2387static void *tcp_seek_last_pos(struct seq_file *seq)
2388{
2389 struct tcp_iter_state *st = seq->private;
2390 int offset = st->offset;
2391 int orig_num = st->num;
2392 void *rc = NULL;
2393
2394 switch (st->state) {
2395 case TCP_SEQ_STATE_LISTENING:
2396 if (st->bucket >= INET_LHTABLE_SIZE)
2397 break;
2398 st->state = TCP_SEQ_STATE_LISTENING;
2399 rc = listening_get_next(seq, NULL);
2400 while (offset-- && rc)
2401 rc = listening_get_next(seq, rc);
2402 if (rc)
2403 break;
2404 st->bucket = 0;
2405 st->state = TCP_SEQ_STATE_ESTABLISHED;
2406 fallthrough;
2407 case TCP_SEQ_STATE_ESTABLISHED:
2408 if (st->bucket > tcp_hashinfo.ehash_mask)
2409 break;
2410 rc = established_get_first(seq);
2411 while (offset-- && rc)
2412 rc = established_get_next(seq, rc);
2413 }
2414
2415 st->num = orig_num;
2416
2417 return rc;
2418}
2419
2420void *tcp_seq_start(struct seq_file *seq, loff_t *pos)
2421{
2422 struct tcp_iter_state *st = seq->private;
2423 void *rc;
2424
2425 if (*pos && *pos == st->last_pos) {
2426 rc = tcp_seek_last_pos(seq);
2427 if (rc)
2428 goto out;
2429 }
2430
2431 st->state = TCP_SEQ_STATE_LISTENING;
2432 st->num = 0;
2433 st->bucket = 0;
2434 st->offset = 0;
2435 rc = *pos ? tcp_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
2436
2437out:
2438 st->last_pos = *pos;
2439 return rc;
2440}
2441EXPORT_SYMBOL(tcp_seq_start);
2442
2443void *tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2444{
2445 struct tcp_iter_state *st = seq->private;
2446 void *rc = NULL;
2447
2448 if (v == SEQ_START_TOKEN) {
2449 rc = tcp_get_idx(seq, 0);
2450 goto out;
2451 }
2452
2453 switch (st->state) {
2454 case TCP_SEQ_STATE_LISTENING:
2455 rc = listening_get_next(seq, v);
2456 if (!rc) {
2457 st->state = TCP_SEQ_STATE_ESTABLISHED;
2458 st->bucket = 0;
2459 st->offset = 0;
2460 rc = established_get_first(seq);
2461 }
2462 break;
2463 case TCP_SEQ_STATE_ESTABLISHED:
2464 rc = established_get_next(seq, v);
2465 break;
2466 }
2467out:
2468 ++*pos;
2469 st->last_pos = *pos;
2470 return rc;
2471}
2472EXPORT_SYMBOL(tcp_seq_next);
2473
2474void tcp_seq_stop(struct seq_file *seq, void *v)
2475{
2476 struct tcp_iter_state *st = seq->private;
2477
2478 switch (st->state) {
2479 case TCP_SEQ_STATE_LISTENING:
2480 if (v != SEQ_START_TOKEN)
2481 spin_unlock(&tcp_hashinfo.listening_hash[st->bucket].lock);
2482 break;
2483 case TCP_SEQ_STATE_ESTABLISHED:
2484 if (v)
2485 spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
2486 break;
2487 }
2488}
2489EXPORT_SYMBOL(tcp_seq_stop);
2490
2491static void get_openreq4(const struct request_sock *req,
2492 struct seq_file *f, int i)
2493{
2494 const struct inet_request_sock *ireq = inet_rsk(req);
2495 long delta = req->rsk_timer.expires - jiffies;
2496
2497 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2498 " %02X %08X:%08X %02X:%08lX %08X %5u %8d %u %d %pK",
2499 i,
2500 ireq->ir_loc_addr,
2501 ireq->ir_num,
2502 ireq->ir_rmt_addr,
2503 ntohs(ireq->ir_rmt_port),
2504 TCP_SYN_RECV,
2505 0, 0, /* could print option size, but that is af dependent. */
2506 1, /* timers active (only the expire timer) */
2507 jiffies_delta_to_clock_t(delta),
2508 req->num_timeout,
2509 from_kuid_munged(seq_user_ns(f),
2510 sock_i_uid(req->rsk_listener)),
2511 0, /* non standard timer */
2512 0, /* open_requests have no inode */
2513 0,
2514 req);
2515}
2516
2517static void get_tcp4_sock(struct sock *sk, struct seq_file *f, int i)
2518{
2519 int timer_active;
2520 unsigned long timer_expires;
2521 const struct tcp_sock *tp = tcp_sk(sk);
2522 const struct inet_connection_sock *icsk = inet_csk(sk);
2523 const struct inet_sock *inet = inet_sk(sk);
2524 const struct fastopen_queue *fastopenq = &icsk->icsk_accept_queue.fastopenq;
2525 __be32 dest = inet->inet_daddr;
2526 __be32 src = inet->inet_rcv_saddr;
2527 __u16 destp = ntohs(inet->inet_dport);
2528 __u16 srcp = ntohs(inet->inet_sport);
2529 int rx_queue;
2530 int state;
2531
2532 if (icsk->icsk_pending == ICSK_TIME_RETRANS ||
2533 icsk->icsk_pending == ICSK_TIME_REO_TIMEOUT ||
2534 icsk->icsk_pending == ICSK_TIME_LOSS_PROBE) {
2535 timer_active = 1;
2536 timer_expires = icsk->icsk_timeout;
2537 } else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
2538 timer_active = 4;
2539 timer_expires = icsk->icsk_timeout;
2540 } else if (timer_pending(&sk->sk_timer)) {
2541 timer_active = 2;
2542 timer_expires = sk->sk_timer.expires;
2543 } else {
2544 timer_active = 0;
2545 timer_expires = jiffies;
2546 }
2547
2548 state = inet_sk_state_load(sk);
2549 if (state == TCP_LISTEN)
2550 rx_queue = READ_ONCE(sk->sk_ack_backlog);
2551 else
2552 /* Because we don't lock the socket,
2553 * we might find a transient negative value.
2554 */
2555 rx_queue = max_t(int, READ_ONCE(tp->rcv_nxt) -
2556 READ_ONCE(tp->copied_seq), 0);
2557
2558 seq_printf(f, "%4d: %08X:%04X %08X:%04X %02X %08X:%08X %02X:%08lX "
2559 "%08X %5u %8d %lu %d %pK %lu %lu %u %u %d",
2560 i, src, srcp, dest, destp, state,
2561 READ_ONCE(tp->write_seq) - tp->snd_una,
2562 rx_queue,
2563 timer_active,
2564 jiffies_delta_to_clock_t(timer_expires - jiffies),
2565 icsk->icsk_retransmits,
2566 from_kuid_munged(seq_user_ns(f), sock_i_uid(sk)),
2567 icsk->icsk_probes_out,
2568 sock_i_ino(sk),
2569 refcount_read(&sk->sk_refcnt), sk,
2570 jiffies_to_clock_t(icsk->icsk_rto),
2571 jiffies_to_clock_t(icsk->icsk_ack.ato),
2572 (icsk->icsk_ack.quick << 1) | inet_csk_in_pingpong_mode(sk),
2573 tp->snd_cwnd,
2574 state == TCP_LISTEN ?
2575 fastopenq->max_qlen :
2576 (tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh));
2577}
2578
2579static void get_timewait4_sock(const struct inet_timewait_sock *tw,
2580 struct seq_file *f, int i)
2581{
2582 long delta = tw->tw_timer.expires - jiffies;
2583 __be32 dest, src;
2584 __u16 destp, srcp;
2585
2586 dest = tw->tw_daddr;
2587 src = tw->tw_rcv_saddr;
2588 destp = ntohs(tw->tw_dport);
2589 srcp = ntohs(tw->tw_sport);
2590
2591 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2592 " %02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK",
2593 i, src, srcp, dest, destp, tw->tw_substate, 0, 0,
2594 3, jiffies_delta_to_clock_t(delta), 0, 0, 0, 0,
2595 refcount_read(&tw->tw_refcnt), tw);
2596}
2597
2598#define TMPSZ 150
2599
2600static int tcp4_seq_show(struct seq_file *seq, void *v)
2601{
2602 struct tcp_iter_state *st;
2603 struct sock *sk = v;
2604
2605 seq_setwidth(seq, TMPSZ - 1);
2606 if (v == SEQ_START_TOKEN) {
2607 seq_puts(seq, " sl local_address rem_address st tx_queue "
2608 "rx_queue tr tm->when retrnsmt uid timeout "
2609 "inode");
2610 goto out;
2611 }
2612 st = seq->private;
2613
2614 if (sk->sk_state == TCP_TIME_WAIT)
2615 get_timewait4_sock(v, seq, st->num);
2616 else if (sk->sk_state == TCP_NEW_SYN_RECV)
2617 get_openreq4(v, seq, st->num);
2618 else
2619 get_tcp4_sock(v, seq, st->num);
2620out:
2621 seq_pad(seq, '\n');
2622 return 0;
2623}
2624
2625#ifdef CONFIG_BPF_SYSCALL
2626struct bpf_iter__tcp {
2627 __bpf_md_ptr(struct bpf_iter_meta *, meta);
2628 __bpf_md_ptr(struct sock_common *, sk_common);
2629 uid_t uid __aligned(8);
2630};
2631
2632static int tcp_prog_seq_show(struct bpf_prog *prog, struct bpf_iter_meta *meta,
2633 struct sock_common *sk_common, uid_t uid)
2634{
2635 struct bpf_iter__tcp ctx;
2636
2637 meta->seq_num--; /* skip SEQ_START_TOKEN */
2638 ctx.meta = meta;
2639 ctx.sk_common = sk_common;
2640 ctx.uid = uid;
2641 return bpf_iter_run_prog(prog, &ctx);
2642}
2643
2644static int bpf_iter_tcp_seq_show(struct seq_file *seq, void *v)
2645{
2646 struct bpf_iter_meta meta;
2647 struct bpf_prog *prog;
2648 struct sock *sk = v;
2649 uid_t uid;
2650
2651 if (v == SEQ_START_TOKEN)
2652 return 0;
2653
2654 if (sk->sk_state == TCP_TIME_WAIT) {
2655 uid = 0;
2656 } else if (sk->sk_state == TCP_NEW_SYN_RECV) {
2657 const struct request_sock *req = v;
2658
2659 uid = from_kuid_munged(seq_user_ns(seq),
2660 sock_i_uid(req->rsk_listener));
2661 } else {
2662 uid = from_kuid_munged(seq_user_ns(seq), sock_i_uid(sk));
2663 }
2664
2665 meta.seq = seq;
2666 prog = bpf_iter_get_info(&meta, false);
2667 return tcp_prog_seq_show(prog, &meta, v, uid);
2668}
2669
2670static void bpf_iter_tcp_seq_stop(struct seq_file *seq, void *v)
2671{
2672 struct bpf_iter_meta meta;
2673 struct bpf_prog *prog;
2674
2675 if (!v) {
2676 meta.seq = seq;
2677 prog = bpf_iter_get_info(&meta, true);
2678 if (prog)
2679 (void)tcp_prog_seq_show(prog, &meta, v, 0);
2680 }
2681
2682 tcp_seq_stop(seq, v);
2683}
2684
2685static const struct seq_operations bpf_iter_tcp_seq_ops = {
2686 .show = bpf_iter_tcp_seq_show,
2687 .start = tcp_seq_start,
2688 .next = tcp_seq_next,
2689 .stop = bpf_iter_tcp_seq_stop,
2690};
2691#endif
2692
2693static const struct seq_operations tcp4_seq_ops = {
2694 .show = tcp4_seq_show,
2695 .start = tcp_seq_start,
2696 .next = tcp_seq_next,
2697 .stop = tcp_seq_stop,
2698};
2699
2700static struct tcp_seq_afinfo tcp4_seq_afinfo = {
2701 .family = AF_INET,
2702};
2703
2704static int __net_init tcp4_proc_init_net(struct net *net)
2705{
2706 if (!proc_create_net_data("tcp", 0444, net->proc_net, &tcp4_seq_ops,
2707 sizeof(struct tcp_iter_state), &tcp4_seq_afinfo))
2708 return -ENOMEM;
2709 return 0;
2710}
2711
2712static void __net_exit tcp4_proc_exit_net(struct net *net)
2713{
2714 remove_proc_entry("tcp", net->proc_net);
2715}
2716
2717static struct pernet_operations tcp4_net_ops = {
2718 .init = tcp4_proc_init_net,
2719 .exit = tcp4_proc_exit_net,
2720};
2721
2722int __init tcp4_proc_init(void)
2723{
2724 return register_pernet_subsys(&tcp4_net_ops);
2725}
2726
2727void tcp4_proc_exit(void)
2728{
2729 unregister_pernet_subsys(&tcp4_net_ops);
2730}
2731#endif /* CONFIG_PROC_FS */
2732
2733struct proto tcp_prot = {
2734 .name = "TCP",
2735 .owner = THIS_MODULE,
2736 .close = tcp_close,
2737 .pre_connect = tcp_v4_pre_connect,
2738 .connect = tcp_v4_connect,
2739 .disconnect = tcp_disconnect,
2740 .accept = inet_csk_accept,
2741 .ioctl = tcp_ioctl,
2742 .init = tcp_v4_init_sock,
2743 .destroy = tcp_v4_destroy_sock,
2744 .shutdown = tcp_shutdown,
2745 .setsockopt = tcp_setsockopt,
2746 .getsockopt = tcp_getsockopt,
2747 .keepalive = tcp_set_keepalive,
2748 .recvmsg = tcp_recvmsg,
2749 .sendmsg = tcp_sendmsg,
2750 .sendpage = tcp_sendpage,
2751 .backlog_rcv = tcp_v4_do_rcv,
2752 .release_cb = tcp_release_cb,
2753 .hash = inet_hash,
2754 .unhash = inet_unhash,
2755 .get_port = inet_csk_get_port,
2756 .enter_memory_pressure = tcp_enter_memory_pressure,
2757 .leave_memory_pressure = tcp_leave_memory_pressure,
2758 .stream_memory_free = tcp_stream_memory_free,
2759 .sockets_allocated = &tcp_sockets_allocated,
2760 .orphan_count = &tcp_orphan_count,
2761 .memory_allocated = &tcp_memory_allocated,
2762 .memory_pressure = &tcp_memory_pressure,
2763 .sysctl_mem = sysctl_tcp_mem,
2764 .sysctl_wmem_offset = offsetof(struct net, ipv4.sysctl_tcp_wmem),
2765 .sysctl_rmem_offset = offsetof(struct net, ipv4.sysctl_tcp_rmem),
2766 .max_header = MAX_TCP_HEADER,
2767 .obj_size = sizeof(struct tcp_sock),
2768 .slab_flags = SLAB_TYPESAFE_BY_RCU,
2769 .twsk_prot = &tcp_timewait_sock_ops,
2770 .rsk_prot = &tcp_request_sock_ops,
2771 .h.hashinfo = &tcp_hashinfo,
2772 .no_autobind = true,
2773 .diag_destroy = tcp_abort,
2774};
2775EXPORT_SYMBOL(tcp_prot);
2776
2777static void __net_exit tcp_sk_exit(struct net *net)
2778{
2779 int cpu;
2780
2781 if (net->ipv4.tcp_congestion_control)
2782 bpf_module_put(net->ipv4.tcp_congestion_control,
2783 net->ipv4.tcp_congestion_control->owner);
2784
2785 for_each_possible_cpu(cpu)
2786 inet_ctl_sock_destroy(*per_cpu_ptr(net->ipv4.tcp_sk, cpu));
2787 free_percpu(net->ipv4.tcp_sk);
2788}
2789
2790static int __net_init tcp_sk_init(struct net *net)
2791{
2792 int res, cpu, cnt;
2793
2794 net->ipv4.tcp_sk = alloc_percpu(struct sock *);
2795 if (!net->ipv4.tcp_sk)
2796 return -ENOMEM;
2797
2798 for_each_possible_cpu(cpu) {
2799 struct sock *sk;
2800
2801 res = inet_ctl_sock_create(&sk, PF_INET, SOCK_RAW,
2802 IPPROTO_TCP, net);
2803 if (res)
2804 goto fail;
2805 sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
2806
2807 /* Please enforce IP_DF and IPID==0 for RST and
2808 * ACK sent in SYN-RECV and TIME-WAIT state.
2809 */
2810 inet_sk(sk)->pmtudisc = IP_PMTUDISC_DO;
2811
2812 *per_cpu_ptr(net->ipv4.tcp_sk, cpu) = sk;
2813 }
2814
2815 net->ipv4.sysctl_tcp_ecn = 2;
2816 net->ipv4.sysctl_tcp_ecn_fallback = 1;
2817
2818 net->ipv4.sysctl_tcp_base_mss = TCP_BASE_MSS;
2819 net->ipv4.sysctl_tcp_min_snd_mss = TCP_MIN_SND_MSS;
2820 net->ipv4.sysctl_tcp_probe_threshold = TCP_PROBE_THRESHOLD;
2821 net->ipv4.sysctl_tcp_probe_interval = TCP_PROBE_INTERVAL;
2822 net->ipv4.sysctl_tcp_mtu_probe_floor = TCP_MIN_SND_MSS;
2823
2824 net->ipv4.sysctl_tcp_keepalive_time = TCP_KEEPALIVE_TIME;
2825 net->ipv4.sysctl_tcp_keepalive_probes = TCP_KEEPALIVE_PROBES;
2826 net->ipv4.sysctl_tcp_keepalive_intvl = TCP_KEEPALIVE_INTVL;
2827
2828 net->ipv4.sysctl_tcp_syn_retries = TCP_SYN_RETRIES;
2829 net->ipv4.sysctl_tcp_synack_retries = TCP_SYNACK_RETRIES;
2830 net->ipv4.sysctl_tcp_syncookies = 1;
2831 net->ipv4.sysctl_tcp_reordering = TCP_FASTRETRANS_THRESH;
2832 net->ipv4.sysctl_tcp_retries1 = TCP_RETR1;
2833 net->ipv4.sysctl_tcp_retries2 = TCP_RETR2;
2834 net->ipv4.sysctl_tcp_orphan_retries = 0;
2835 net->ipv4.sysctl_tcp_fin_timeout = TCP_FIN_TIMEOUT;
2836 net->ipv4.sysctl_tcp_notsent_lowat = UINT_MAX;
2837 net->ipv4.sysctl_tcp_tw_reuse = 2;
2838 net->ipv4.sysctl_tcp_no_ssthresh_metrics_save = 1;
2839
2840 cnt = tcp_hashinfo.ehash_mask + 1;
2841 net->ipv4.tcp_death_row.sysctl_max_tw_buckets = cnt / 2;
2842 net->ipv4.tcp_death_row.hashinfo = &tcp_hashinfo;
2843
2844 net->ipv4.sysctl_max_syn_backlog = max(128, cnt / 128);
2845 net->ipv4.sysctl_tcp_sack = 1;
2846 net->ipv4.sysctl_tcp_window_scaling = 1;
2847 net->ipv4.sysctl_tcp_timestamps = 1;
2848 net->ipv4.sysctl_tcp_early_retrans = 3;
2849 net->ipv4.sysctl_tcp_recovery = TCP_RACK_LOSS_DETECTION;
2850 net->ipv4.sysctl_tcp_slow_start_after_idle = 1; /* By default, RFC2861 behavior. */
2851 net->ipv4.sysctl_tcp_retrans_collapse = 1;
2852 net->ipv4.sysctl_tcp_max_reordering = 300;
2853 net->ipv4.sysctl_tcp_dsack = 1;
2854 net->ipv4.sysctl_tcp_app_win = 31;
2855 net->ipv4.sysctl_tcp_adv_win_scale = 1;
2856 net->ipv4.sysctl_tcp_frto = 2;
2857 net->ipv4.sysctl_tcp_moderate_rcvbuf = 1;
2858 /* This limits the percentage of the congestion window which we
2859 * will allow a single TSO frame to consume. Building TSO frames
2860 * which are too large can cause TCP streams to be bursty.
2861 */
2862 net->ipv4.sysctl_tcp_tso_win_divisor = 3;
2863 /* Default TSQ limit of 16 TSO segments */
2864 net->ipv4.sysctl_tcp_limit_output_bytes = 16 * 65536;
2865 /* rfc5961 challenge ack rate limiting */
2866 net->ipv4.sysctl_tcp_challenge_ack_limit = 1000;
2867 net->ipv4.sysctl_tcp_min_tso_segs = 2;
2868 net->ipv4.sysctl_tcp_min_rtt_wlen = 300;
2869 net->ipv4.sysctl_tcp_autocorking = 1;
2870 net->ipv4.sysctl_tcp_invalid_ratelimit = HZ/2;
2871 net->ipv4.sysctl_tcp_pacing_ss_ratio = 200;
2872 net->ipv4.sysctl_tcp_pacing_ca_ratio = 120;
2873 if (net != &init_net) {
2874 memcpy(net->ipv4.sysctl_tcp_rmem,
2875 init_net.ipv4.sysctl_tcp_rmem,
2876 sizeof(init_net.ipv4.sysctl_tcp_rmem));
2877 memcpy(net->ipv4.sysctl_tcp_wmem,
2878 init_net.ipv4.sysctl_tcp_wmem,
2879 sizeof(init_net.ipv4.sysctl_tcp_wmem));
2880 }
2881 net->ipv4.sysctl_tcp_comp_sack_delay_ns = NSEC_PER_MSEC;
2882 net->ipv4.sysctl_tcp_comp_sack_slack_ns = 100 * NSEC_PER_USEC;
2883 net->ipv4.sysctl_tcp_comp_sack_nr = 44;
2884 net->ipv4.sysctl_tcp_fastopen = TFO_CLIENT_ENABLE;
2885 spin_lock_init(&net->ipv4.tcp_fastopen_ctx_lock);
2886 net->ipv4.sysctl_tcp_fastopen_blackhole_timeout = 60 * 60;
2887 atomic_set(&net->ipv4.tfo_active_disable_times, 0);
2888
2889 /* Reno is always built in */
2890 if (!net_eq(net, &init_net) &&
2891 bpf_try_module_get(init_net.ipv4.tcp_congestion_control,
2892 init_net.ipv4.tcp_congestion_control->owner))
2893 net->ipv4.tcp_congestion_control = init_net.ipv4.tcp_congestion_control;
2894 else
2895 net->ipv4.tcp_congestion_control = &tcp_reno;
2896
2897 return 0;
2898fail:
2899 tcp_sk_exit(net);
2900
2901 return res;
2902}
2903
2904static void __net_exit tcp_sk_exit_batch(struct list_head *net_exit_list)
2905{
2906 struct net *net;
2907
2908 inet_twsk_purge(&tcp_hashinfo, AF_INET);
2909
2910 list_for_each_entry(net, net_exit_list, exit_list)
2911 tcp_fastopen_ctx_destroy(net);
2912}
2913
2914static struct pernet_operations __net_initdata tcp_sk_ops = {
2915 .init = tcp_sk_init,
2916 .exit = tcp_sk_exit,
2917 .exit_batch = tcp_sk_exit_batch,
2918};
2919
2920#if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS)
2921DEFINE_BPF_ITER_FUNC(tcp, struct bpf_iter_meta *meta,
2922 struct sock_common *sk_common, uid_t uid)
2923
2924static int bpf_iter_init_tcp(void *priv_data, struct bpf_iter_aux_info *aux)
2925{
2926 struct tcp_iter_state *st = priv_data;
2927 struct tcp_seq_afinfo *afinfo;
2928 int ret;
2929
2930 afinfo = kmalloc(sizeof(*afinfo), GFP_USER | __GFP_NOWARN);
2931 if (!afinfo)
2932 return -ENOMEM;
2933
2934 afinfo->family = AF_UNSPEC;
2935 st->bpf_seq_afinfo = afinfo;
2936 ret = bpf_iter_init_seq_net(priv_data, aux);
2937 if (ret)
2938 kfree(afinfo);
2939 return ret;
2940}
2941
2942static void bpf_iter_fini_tcp(void *priv_data)
2943{
2944 struct tcp_iter_state *st = priv_data;
2945
2946 kfree(st->bpf_seq_afinfo);
2947 bpf_iter_fini_seq_net(priv_data);
2948}
2949
2950static const struct bpf_iter_seq_info tcp_seq_info = {
2951 .seq_ops = &bpf_iter_tcp_seq_ops,
2952 .init_seq_private = bpf_iter_init_tcp,
2953 .fini_seq_private = bpf_iter_fini_tcp,
2954 .seq_priv_size = sizeof(struct tcp_iter_state),
2955};
2956
2957static struct bpf_iter_reg tcp_reg_info = {
2958 .target = "tcp",
2959 .ctx_arg_info_size = 1,
2960 .ctx_arg_info = {
2961 { offsetof(struct bpf_iter__tcp, sk_common),
2962 PTR_TO_BTF_ID_OR_NULL },
2963 },
2964 .seq_info = &tcp_seq_info,
2965};
2966
2967static void __init bpf_iter_register(void)
2968{
2969 tcp_reg_info.ctx_arg_info[0].btf_id = btf_sock_ids[BTF_SOCK_TYPE_SOCK_COMMON];
2970 if (bpf_iter_reg_target(&tcp_reg_info))
2971 pr_warn("Warning: could not register bpf iterator tcp\n");
2972}
2973
2974#endif
2975
2976void __init tcp_v4_init(void)
2977{
2978 if (register_pernet_subsys(&tcp_sk_ops))
2979 panic("Failed to create the TCP control socket.\n");
2980
2981#if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS)
2982 bpf_iter_register();
2983#endif
2984}
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
143static int tcp_v4_pre_connect(struct sock *sk, struct sockaddr *uaddr,
144 int addr_len)
145{
146 /* This check is replicated from tcp_v4_connect() and intended to
147 * prevent BPF program called below from accessing bytes that are out
148 * of the bound specified by user in addr_len.
149 */
150 if (addr_len < sizeof(struct sockaddr_in))
151 return -EINVAL;
152
153 sock_owned_by_me(sk);
154
155 return BPF_CGROUP_RUN_PROG_INET4_CONNECT(sk, uaddr);
156}
157
158/* This will initiate an outgoing connection. */
159int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
160{
161 struct sockaddr_in *usin = (struct sockaddr_in *)uaddr;
162 struct inet_sock *inet = inet_sk(sk);
163 struct tcp_sock *tp = tcp_sk(sk);
164 __be16 orig_sport, orig_dport;
165 __be32 daddr, nexthop;
166 struct flowi4 *fl4;
167 struct rtable *rt;
168 int err;
169 struct ip_options_rcu *inet_opt;
170 struct inet_timewait_death_row *tcp_death_row = &sock_net(sk)->ipv4.tcp_death_row;
171
172 if (addr_len < sizeof(struct sockaddr_in))
173 return -EINVAL;
174
175 if (usin->sin_family != AF_INET)
176 return -EAFNOSUPPORT;
177
178 nexthop = daddr = usin->sin_addr.s_addr;
179 inet_opt = rcu_dereference_protected(inet->inet_opt,
180 lockdep_sock_is_held(sk));
181 if (inet_opt && inet_opt->opt.srr) {
182 if (!daddr)
183 return -EINVAL;
184 nexthop = inet_opt->opt.faddr;
185 }
186
187 orig_sport = inet->inet_sport;
188 orig_dport = usin->sin_port;
189 fl4 = &inet->cork.fl.u.ip4;
190 rt = ip_route_connect(fl4, nexthop, inet->inet_saddr,
191 RT_CONN_FLAGS(sk), sk->sk_bound_dev_if,
192 IPPROTO_TCP,
193 orig_sport, orig_dport, sk);
194 if (IS_ERR(rt)) {
195 err = PTR_ERR(rt);
196 if (err == -ENETUNREACH)
197 IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTNOROUTES);
198 return err;
199 }
200
201 if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) {
202 ip_rt_put(rt);
203 return -ENETUNREACH;
204 }
205
206 if (!inet_opt || !inet_opt->opt.srr)
207 daddr = fl4->daddr;
208
209 if (!inet->inet_saddr)
210 inet->inet_saddr = fl4->saddr;
211 sk_rcv_saddr_set(sk, inet->inet_saddr);
212
213 if (tp->rx_opt.ts_recent_stamp && inet->inet_daddr != daddr) {
214 /* Reset inherited state */
215 tp->rx_opt.ts_recent = 0;
216 tp->rx_opt.ts_recent_stamp = 0;
217 if (likely(!tp->repair))
218 tp->write_seq = 0;
219 }
220
221 inet->inet_dport = usin->sin_port;
222 sk_daddr_set(sk, daddr);
223
224 inet_csk(sk)->icsk_ext_hdr_len = 0;
225 if (inet_opt)
226 inet_csk(sk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
227
228 tp->rx_opt.mss_clamp = TCP_MSS_DEFAULT;
229
230 /* Socket identity is still unknown (sport may be zero).
231 * However we set state to SYN-SENT and not releasing socket
232 * lock select source port, enter ourselves into the hash tables and
233 * complete initialization after this.
234 */
235 tcp_set_state(sk, TCP_SYN_SENT);
236 err = inet_hash_connect(tcp_death_row, sk);
237 if (err)
238 goto failure;
239
240 sk_set_txhash(sk);
241
242 rt = ip_route_newports(fl4, rt, orig_sport, orig_dport,
243 inet->inet_sport, inet->inet_dport, sk);
244 if (IS_ERR(rt)) {
245 err = PTR_ERR(rt);
246 rt = NULL;
247 goto failure;
248 }
249 /* OK, now commit destination to socket. */
250 sk->sk_gso_type = SKB_GSO_TCPV4;
251 sk_setup_caps(sk, &rt->dst);
252 rt = NULL;
253
254 if (likely(!tp->repair)) {
255 if (!tp->write_seq)
256 tp->write_seq = secure_tcp_seq(inet->inet_saddr,
257 inet->inet_daddr,
258 inet->inet_sport,
259 usin->sin_port);
260 tp->tsoffset = secure_tcp_ts_off(sock_net(sk),
261 inet->inet_saddr,
262 inet->inet_daddr);
263 }
264
265 inet->inet_id = tp->write_seq ^ jiffies;
266
267 if (tcp_fastopen_defer_connect(sk, &err))
268 return err;
269 if (err)
270 goto failure;
271
272 err = tcp_connect(sk);
273
274 if (err)
275 goto failure;
276
277 return 0;
278
279failure:
280 /*
281 * This unhashes the socket and releases the local port,
282 * if necessary.
283 */
284 tcp_set_state(sk, TCP_CLOSE);
285 ip_rt_put(rt);
286 sk->sk_route_caps = 0;
287 inet->inet_dport = 0;
288 return err;
289}
290EXPORT_SYMBOL(tcp_v4_connect);
291
292/*
293 * This routine reacts to ICMP_FRAG_NEEDED mtu indications as defined in RFC1191.
294 * It can be called through tcp_release_cb() if socket was owned by user
295 * at the time tcp_v4_err() was called to handle ICMP message.
296 */
297void tcp_v4_mtu_reduced(struct sock *sk)
298{
299 struct inet_sock *inet = inet_sk(sk);
300 struct dst_entry *dst;
301 u32 mtu;
302
303 if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE))
304 return;
305 mtu = tcp_sk(sk)->mtu_info;
306 dst = inet_csk_update_pmtu(sk, mtu);
307 if (!dst)
308 return;
309
310 /* Something is about to be wrong... Remember soft error
311 * for the case, if this connection will not able to recover.
312 */
313 if (mtu < dst_mtu(dst) && ip_dont_fragment(sk, dst))
314 sk->sk_err_soft = EMSGSIZE;
315
316 mtu = dst_mtu(dst);
317
318 if (inet->pmtudisc != IP_PMTUDISC_DONT &&
319 ip_sk_accept_pmtu(sk) &&
320 inet_csk(sk)->icsk_pmtu_cookie > mtu) {
321 tcp_sync_mss(sk, mtu);
322
323 /* Resend the TCP packet because it's
324 * clear that the old packet has been
325 * dropped. This is the new "fast" path mtu
326 * discovery.
327 */
328 tcp_simple_retransmit(sk);
329 } /* else let the usual retransmit timer handle it */
330}
331EXPORT_SYMBOL(tcp_v4_mtu_reduced);
332
333static void do_redirect(struct sk_buff *skb, struct sock *sk)
334{
335 struct dst_entry *dst = __sk_dst_check(sk, 0);
336
337 if (dst)
338 dst->ops->redirect(dst, sk, skb);
339}
340
341
342/* handle ICMP messages on TCP_NEW_SYN_RECV request sockets */
343void tcp_req_err(struct sock *sk, u32 seq, bool abort)
344{
345 struct request_sock *req = inet_reqsk(sk);
346 struct net *net = sock_net(sk);
347
348 /* ICMPs are not backlogged, hence we cannot get
349 * an established socket here.
350 */
351 if (seq != tcp_rsk(req)->snt_isn) {
352 __NET_INC_STATS(net, LINUX_MIB_OUTOFWINDOWICMPS);
353 } else if (abort) {
354 /*
355 * Still in SYN_RECV, just remove it silently.
356 * There is no good way to pass the error to the newly
357 * created socket, and POSIX does not want network
358 * errors returned from accept().
359 */
360 inet_csk_reqsk_queue_drop(req->rsk_listener, req);
361 tcp_listendrop(req->rsk_listener);
362 }
363 reqsk_put(req);
364}
365EXPORT_SYMBOL(tcp_req_err);
366
367/*
368 * This routine is called by the ICMP module when it gets some
369 * sort of error condition. If err < 0 then the socket should
370 * be closed and the error returned to the user. If err > 0
371 * it's just the icmp type << 8 | icmp code. After adjustment
372 * header points to the first 8 bytes of the tcp header. We need
373 * to find the appropriate port.
374 *
375 * The locking strategy used here is very "optimistic". When
376 * someone else accesses the socket the ICMP is just dropped
377 * and for some paths there is no check at all.
378 * A more general error queue to queue errors for later handling
379 * is probably better.
380 *
381 */
382
383void tcp_v4_err(struct sk_buff *icmp_skb, u32 info)
384{
385 const struct iphdr *iph = (const struct iphdr *)icmp_skb->data;
386 struct tcphdr *th = (struct tcphdr *)(icmp_skb->data + (iph->ihl << 2));
387 struct inet_connection_sock *icsk;
388 struct tcp_sock *tp;
389 struct inet_sock *inet;
390 const int type = icmp_hdr(icmp_skb)->type;
391 const int code = icmp_hdr(icmp_skb)->code;
392 struct sock *sk;
393 struct sk_buff *skb;
394 struct request_sock *fastopen;
395 u32 seq, snd_una;
396 s32 remaining;
397 u32 delta_us;
398 int err;
399 struct net *net = dev_net(icmp_skb->dev);
400
401 sk = __inet_lookup_established(net, &tcp_hashinfo, iph->daddr,
402 th->dest, iph->saddr, ntohs(th->source),
403 inet_iif(icmp_skb), 0);
404 if (!sk) {
405 __ICMP_INC_STATS(net, ICMP_MIB_INERRORS);
406 return;
407 }
408 if (sk->sk_state == TCP_TIME_WAIT) {
409 inet_twsk_put(inet_twsk(sk));
410 return;
411 }
412 seq = ntohl(th->seq);
413 if (sk->sk_state == TCP_NEW_SYN_RECV)
414 return tcp_req_err(sk, seq,
415 type == ICMP_PARAMETERPROB ||
416 type == ICMP_TIME_EXCEEDED ||
417 (type == ICMP_DEST_UNREACH &&
418 (code == ICMP_NET_UNREACH ||
419 code == ICMP_HOST_UNREACH)));
420
421 bh_lock_sock(sk);
422 /* If too many ICMPs get dropped on busy
423 * servers this needs to be solved differently.
424 * We do take care of PMTU discovery (RFC1191) special case :
425 * we can receive locally generated ICMP messages while socket is held.
426 */
427 if (sock_owned_by_user(sk)) {
428 if (!(type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED))
429 __NET_INC_STATS(net, LINUX_MIB_LOCKDROPPEDICMPS);
430 }
431 if (sk->sk_state == TCP_CLOSE)
432 goto out;
433
434 if (unlikely(iph->ttl < inet_sk(sk)->min_ttl)) {
435 __NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP);
436 goto out;
437 }
438
439 icsk = inet_csk(sk);
440 tp = tcp_sk(sk);
441 /* XXX (TFO) - tp->snd_una should be ISN (tcp_create_openreq_child() */
442 fastopen = tp->fastopen_rsk;
443 snd_una = fastopen ? tcp_rsk(fastopen)->snt_isn : tp->snd_una;
444 if (sk->sk_state != TCP_LISTEN &&
445 !between(seq, snd_una, tp->snd_nxt)) {
446 __NET_INC_STATS(net, LINUX_MIB_OUTOFWINDOWICMPS);
447 goto out;
448 }
449
450 switch (type) {
451 case ICMP_REDIRECT:
452 if (!sock_owned_by_user(sk))
453 do_redirect(icmp_skb, sk);
454 goto out;
455 case ICMP_SOURCE_QUENCH:
456 /* Just silently ignore these. */
457 goto out;
458 case ICMP_PARAMETERPROB:
459 err = EPROTO;
460 break;
461 case ICMP_DEST_UNREACH:
462 if (code > NR_ICMP_UNREACH)
463 goto out;
464
465 if (code == ICMP_FRAG_NEEDED) { /* PMTU discovery (RFC1191) */
466 /* We are not interested in TCP_LISTEN and open_requests
467 * (SYN-ACKs send out by Linux are always <576bytes so
468 * they should go through unfragmented).
469 */
470 if (sk->sk_state == TCP_LISTEN)
471 goto out;
472
473 tp->mtu_info = info;
474 if (!sock_owned_by_user(sk)) {
475 tcp_v4_mtu_reduced(sk);
476 } else {
477 if (!test_and_set_bit(TCP_MTU_REDUCED_DEFERRED, &sk->sk_tsq_flags))
478 sock_hold(sk);
479 }
480 goto out;
481 }
482
483 err = icmp_err_convert[code].errno;
484 /* check if icmp_skb allows revert of backoff
485 * (see draft-zimmermann-tcp-lcd) */
486 if (code != ICMP_NET_UNREACH && code != ICMP_HOST_UNREACH)
487 break;
488 if (seq != tp->snd_una || !icsk->icsk_retransmits ||
489 !icsk->icsk_backoff || fastopen)
490 break;
491
492 if (sock_owned_by_user(sk))
493 break;
494
495 icsk->icsk_backoff--;
496 icsk->icsk_rto = tp->srtt_us ? __tcp_set_rto(tp) :
497 TCP_TIMEOUT_INIT;
498 icsk->icsk_rto = inet_csk_rto_backoff(icsk, TCP_RTO_MAX);
499
500 skb = tcp_rtx_queue_head(sk);
501 BUG_ON(!skb);
502
503 tcp_mstamp_refresh(tp);
504 delta_us = (u32)(tp->tcp_mstamp - skb->skb_mstamp);
505 remaining = icsk->icsk_rto -
506 usecs_to_jiffies(delta_us);
507
508 if (remaining > 0) {
509 inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
510 remaining, TCP_RTO_MAX);
511 } else {
512 /* RTO revert clocked out retransmission.
513 * Will retransmit now */
514 tcp_retransmit_timer(sk);
515 }
516
517 break;
518 case ICMP_TIME_EXCEEDED:
519 err = EHOSTUNREACH;
520 break;
521 default:
522 goto out;
523 }
524
525 switch (sk->sk_state) {
526 case TCP_SYN_SENT:
527 case TCP_SYN_RECV:
528 /* Only in fast or simultaneous open. If a fast open socket is
529 * is already accepted it is treated as a connected one below.
530 */
531 if (fastopen && !fastopen->sk)
532 break;
533
534 if (!sock_owned_by_user(sk)) {
535 sk->sk_err = err;
536
537 sk->sk_error_report(sk);
538
539 tcp_done(sk);
540 } else {
541 sk->sk_err_soft = err;
542 }
543 goto out;
544 }
545
546 /* If we've already connected we will keep trying
547 * until we time out, or the user gives up.
548 *
549 * rfc1122 4.2.3.9 allows to consider as hard errors
550 * only PROTO_UNREACH and PORT_UNREACH (well, FRAG_FAILED too,
551 * but it is obsoleted by pmtu discovery).
552 *
553 * Note, that in modern internet, where routing is unreliable
554 * and in each dark corner broken firewalls sit, sending random
555 * errors ordered by their masters even this two messages finally lose
556 * their original sense (even Linux sends invalid PORT_UNREACHs)
557 *
558 * Now we are in compliance with RFCs.
559 * --ANK (980905)
560 */
561
562 inet = inet_sk(sk);
563 if (!sock_owned_by_user(sk) && inet->recverr) {
564 sk->sk_err = err;
565 sk->sk_error_report(sk);
566 } else { /* Only an error on timeout */
567 sk->sk_err_soft = err;
568 }
569
570out:
571 bh_unlock_sock(sk);
572 sock_put(sk);
573}
574
575void __tcp_v4_send_check(struct sk_buff *skb, __be32 saddr, __be32 daddr)
576{
577 struct tcphdr *th = tcp_hdr(skb);
578
579 th->check = ~tcp_v4_check(skb->len, saddr, daddr, 0);
580 skb->csum_start = skb_transport_header(skb) - skb->head;
581 skb->csum_offset = offsetof(struct tcphdr, check);
582}
583
584/* This routine computes an IPv4 TCP checksum. */
585void tcp_v4_send_check(struct sock *sk, struct sk_buff *skb)
586{
587 const struct inet_sock *inet = inet_sk(sk);
588
589 __tcp_v4_send_check(skb, inet->inet_saddr, inet->inet_daddr);
590}
591EXPORT_SYMBOL(tcp_v4_send_check);
592
593/*
594 * This routine will send an RST to the other tcp.
595 *
596 * Someone asks: why I NEVER use socket parameters (TOS, TTL etc.)
597 * for reset.
598 * Answer: if a packet caused RST, it is not for a socket
599 * existing in our system, if it is matched to a socket,
600 * it is just duplicate segment or bug in other side's TCP.
601 * So that we build reply only basing on parameters
602 * arrived with segment.
603 * Exception: precedence violation. We do not implement it in any case.
604 */
605
606static void tcp_v4_send_reset(const struct sock *sk, struct sk_buff *skb)
607{
608 const struct tcphdr *th = tcp_hdr(skb);
609 struct {
610 struct tcphdr th;
611#ifdef CONFIG_TCP_MD5SIG
612 __be32 opt[(TCPOLEN_MD5SIG_ALIGNED >> 2)];
613#endif
614 } rep;
615 struct ip_reply_arg arg;
616#ifdef CONFIG_TCP_MD5SIG
617 struct tcp_md5sig_key *key = NULL;
618 const __u8 *hash_location = NULL;
619 unsigned char newhash[16];
620 int genhash;
621 struct sock *sk1 = NULL;
622#endif
623 struct net *net;
624
625 /* Never send a reset in response to a reset. */
626 if (th->rst)
627 return;
628
629 /* If sk not NULL, it means we did a successful lookup and incoming
630 * route had to be correct. prequeue might have dropped our dst.
631 */
632 if (!sk && skb_rtable(skb)->rt_type != RTN_LOCAL)
633 return;
634
635 /* Swap the send and the receive. */
636 memset(&rep, 0, sizeof(rep));
637 rep.th.dest = th->source;
638 rep.th.source = th->dest;
639 rep.th.doff = sizeof(struct tcphdr) / 4;
640 rep.th.rst = 1;
641
642 if (th->ack) {
643 rep.th.seq = th->ack_seq;
644 } else {
645 rep.th.ack = 1;
646 rep.th.ack_seq = htonl(ntohl(th->seq) + th->syn + th->fin +
647 skb->len - (th->doff << 2));
648 }
649
650 memset(&arg, 0, sizeof(arg));
651 arg.iov[0].iov_base = (unsigned char *)&rep;
652 arg.iov[0].iov_len = sizeof(rep.th);
653
654 net = sk ? sock_net(sk) : dev_net(skb_dst(skb)->dev);
655#ifdef CONFIG_TCP_MD5SIG
656 rcu_read_lock();
657 hash_location = tcp_parse_md5sig_option(th);
658 if (sk && sk_fullsock(sk)) {
659 key = tcp_md5_do_lookup(sk, (union tcp_md5_addr *)
660 &ip_hdr(skb)->saddr, AF_INET);
661 } else if (hash_location) {
662 /*
663 * active side is lost. Try to find listening socket through
664 * source port, and then find md5 key through listening socket.
665 * we are not loose security here:
666 * Incoming packet is checked with md5 hash with finding key,
667 * no RST generated if md5 hash doesn't match.
668 */
669 sk1 = __inet_lookup_listener(net, &tcp_hashinfo, NULL, 0,
670 ip_hdr(skb)->saddr,
671 th->source, ip_hdr(skb)->daddr,
672 ntohs(th->source), inet_iif(skb),
673 tcp_v4_sdif(skb));
674 /* don't send rst if it can't find key */
675 if (!sk1)
676 goto out;
677
678 key = tcp_md5_do_lookup(sk1, (union tcp_md5_addr *)
679 &ip_hdr(skb)->saddr, AF_INET);
680 if (!key)
681 goto out;
682
683
684 genhash = tcp_v4_md5_hash_skb(newhash, key, NULL, skb);
685 if (genhash || memcmp(hash_location, newhash, 16) != 0)
686 goto out;
687
688 }
689
690 if (key) {
691 rep.opt[0] = htonl((TCPOPT_NOP << 24) |
692 (TCPOPT_NOP << 16) |
693 (TCPOPT_MD5SIG << 8) |
694 TCPOLEN_MD5SIG);
695 /* Update length and the length the header thinks exists */
696 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED;
697 rep.th.doff = arg.iov[0].iov_len / 4;
698
699 tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[1],
700 key, ip_hdr(skb)->saddr,
701 ip_hdr(skb)->daddr, &rep.th);
702 }
703#endif
704 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
705 ip_hdr(skb)->saddr, /* XXX */
706 arg.iov[0].iov_len, IPPROTO_TCP, 0);
707 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
708 arg.flags = (sk && inet_sk_transparent(sk)) ? IP_REPLY_ARG_NOSRCCHECK : 0;
709
710 /* When socket is gone, all binding information is lost.
711 * routing might fail in this case. No choice here, if we choose to force
712 * input interface, we will misroute in case of asymmetric route.
713 */
714 if (sk) {
715 arg.bound_dev_if = sk->sk_bound_dev_if;
716 if (sk_fullsock(sk))
717 trace_tcp_send_reset(sk, skb);
718 }
719
720 BUILD_BUG_ON(offsetof(struct sock, sk_bound_dev_if) !=
721 offsetof(struct inet_timewait_sock, tw_bound_dev_if));
722
723 arg.tos = ip_hdr(skb)->tos;
724 arg.uid = sock_net_uid(net, sk && sk_fullsock(sk) ? sk : NULL);
725 local_bh_disable();
726 ip_send_unicast_reply(*this_cpu_ptr(net->ipv4.tcp_sk),
727 skb, &TCP_SKB_CB(skb)->header.h4.opt,
728 ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
729 &arg, arg.iov[0].iov_len);
730
731 __TCP_INC_STATS(net, TCP_MIB_OUTSEGS);
732 __TCP_INC_STATS(net, TCP_MIB_OUTRSTS);
733 local_bh_enable();
734
735#ifdef CONFIG_TCP_MD5SIG
736out:
737 rcu_read_unlock();
738#endif
739}
740
741/* The code following below sending ACKs in SYN-RECV and TIME-WAIT states
742 outside socket context is ugly, certainly. What can I do?
743 */
744
745static void tcp_v4_send_ack(const struct sock *sk,
746 struct sk_buff *skb, u32 seq, u32 ack,
747 u32 win, u32 tsval, u32 tsecr, int oif,
748 struct tcp_md5sig_key *key,
749 int reply_flags, u8 tos)
750{
751 const struct tcphdr *th = tcp_hdr(skb);
752 struct {
753 struct tcphdr th;
754 __be32 opt[(TCPOLEN_TSTAMP_ALIGNED >> 2)
755#ifdef CONFIG_TCP_MD5SIG
756 + (TCPOLEN_MD5SIG_ALIGNED >> 2)
757#endif
758 ];
759 } rep;
760 struct net *net = sock_net(sk);
761 struct ip_reply_arg arg;
762
763 memset(&rep.th, 0, sizeof(struct tcphdr));
764 memset(&arg, 0, sizeof(arg));
765
766 arg.iov[0].iov_base = (unsigned char *)&rep;
767 arg.iov[0].iov_len = sizeof(rep.th);
768 if (tsecr) {
769 rep.opt[0] = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
770 (TCPOPT_TIMESTAMP << 8) |
771 TCPOLEN_TIMESTAMP);
772 rep.opt[1] = htonl(tsval);
773 rep.opt[2] = htonl(tsecr);
774 arg.iov[0].iov_len += TCPOLEN_TSTAMP_ALIGNED;
775 }
776
777 /* Swap the send and the receive. */
778 rep.th.dest = th->source;
779 rep.th.source = th->dest;
780 rep.th.doff = arg.iov[0].iov_len / 4;
781 rep.th.seq = htonl(seq);
782 rep.th.ack_seq = htonl(ack);
783 rep.th.ack = 1;
784 rep.th.window = htons(win);
785
786#ifdef CONFIG_TCP_MD5SIG
787 if (key) {
788 int offset = (tsecr) ? 3 : 0;
789
790 rep.opt[offset++] = htonl((TCPOPT_NOP << 24) |
791 (TCPOPT_NOP << 16) |
792 (TCPOPT_MD5SIG << 8) |
793 TCPOLEN_MD5SIG);
794 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED;
795 rep.th.doff = arg.iov[0].iov_len/4;
796
797 tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[offset],
798 key, ip_hdr(skb)->saddr,
799 ip_hdr(skb)->daddr, &rep.th);
800 }
801#endif
802 arg.flags = reply_flags;
803 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
804 ip_hdr(skb)->saddr, /* XXX */
805 arg.iov[0].iov_len, IPPROTO_TCP, 0);
806 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
807 if (oif)
808 arg.bound_dev_if = oif;
809 arg.tos = tos;
810 arg.uid = sock_net_uid(net, sk_fullsock(sk) ? sk : NULL);
811 local_bh_disable();
812 ip_send_unicast_reply(*this_cpu_ptr(net->ipv4.tcp_sk),
813 skb, &TCP_SKB_CB(skb)->header.h4.opt,
814 ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
815 &arg, arg.iov[0].iov_len);
816
817 __TCP_INC_STATS(net, TCP_MIB_OUTSEGS);
818 local_bh_enable();
819}
820
821static void tcp_v4_timewait_ack(struct sock *sk, struct sk_buff *skb)
822{
823 struct inet_timewait_sock *tw = inet_twsk(sk);
824 struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
825
826 tcp_v4_send_ack(sk, skb,
827 tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
828 tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
829 tcp_time_stamp_raw() + tcptw->tw_ts_offset,
830 tcptw->tw_ts_recent,
831 tw->tw_bound_dev_if,
832 tcp_twsk_md5_key(tcptw),
833 tw->tw_transparent ? IP_REPLY_ARG_NOSRCCHECK : 0,
834 tw->tw_tos
835 );
836
837 inet_twsk_put(tw);
838}
839
840static void tcp_v4_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb,
841 struct request_sock *req)
842{
843 /* sk->sk_state == TCP_LISTEN -> for regular TCP_SYN_RECV
844 * sk->sk_state == TCP_SYN_RECV -> for Fast Open.
845 */
846 u32 seq = (sk->sk_state == TCP_LISTEN) ? tcp_rsk(req)->snt_isn + 1 :
847 tcp_sk(sk)->snd_nxt;
848
849 /* RFC 7323 2.3
850 * The window field (SEG.WND) of every outgoing segment, with the
851 * exception of <SYN> segments, MUST be right-shifted by
852 * Rcv.Wind.Shift bits:
853 */
854 tcp_v4_send_ack(sk, skb, seq,
855 tcp_rsk(req)->rcv_nxt,
856 req->rsk_rcv_wnd >> inet_rsk(req)->rcv_wscale,
857 tcp_time_stamp_raw() + tcp_rsk(req)->ts_off,
858 req->ts_recent,
859 0,
860 tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&ip_hdr(skb)->saddr,
861 AF_INET),
862 inet_rsk(req)->no_srccheck ? IP_REPLY_ARG_NOSRCCHECK : 0,
863 ip_hdr(skb)->tos);
864}
865
866/*
867 * Send a SYN-ACK after having received a SYN.
868 * This still operates on a request_sock only, not on a big
869 * socket.
870 */
871static int tcp_v4_send_synack(const struct sock *sk, struct dst_entry *dst,
872 struct flowi *fl,
873 struct request_sock *req,
874 struct tcp_fastopen_cookie *foc,
875 enum tcp_synack_type synack_type)
876{
877 const struct inet_request_sock *ireq = inet_rsk(req);
878 struct flowi4 fl4;
879 int err = -1;
880 struct sk_buff *skb;
881
882 /* First, grab a route. */
883 if (!dst && (dst = inet_csk_route_req(sk, &fl4, req)) == NULL)
884 return -1;
885
886 skb = tcp_make_synack(sk, dst, req, foc, synack_type);
887
888 if (skb) {
889 __tcp_v4_send_check(skb, ireq->ir_loc_addr, ireq->ir_rmt_addr);
890
891 err = ip_build_and_send_pkt(skb, sk, ireq->ir_loc_addr,
892 ireq->ir_rmt_addr,
893 ireq_opt_deref(ireq));
894 err = net_xmit_eval(err);
895 }
896
897 return err;
898}
899
900/*
901 * IPv4 request_sock destructor.
902 */
903static void tcp_v4_reqsk_destructor(struct request_sock *req)
904{
905 kfree(rcu_dereference_protected(inet_rsk(req)->ireq_opt, 1));
906}
907
908#ifdef CONFIG_TCP_MD5SIG
909/*
910 * RFC2385 MD5 checksumming requires a mapping of
911 * IP address->MD5 Key.
912 * We need to maintain these in the sk structure.
913 */
914
915/* Find the Key structure for an address. */
916struct tcp_md5sig_key *tcp_md5_do_lookup(const struct sock *sk,
917 const union tcp_md5_addr *addr,
918 int family)
919{
920 const struct tcp_sock *tp = tcp_sk(sk);
921 struct tcp_md5sig_key *key;
922 const struct tcp_md5sig_info *md5sig;
923 __be32 mask;
924 struct tcp_md5sig_key *best_match = NULL;
925 bool match;
926
927 /* caller either holds rcu_read_lock() or socket lock */
928 md5sig = rcu_dereference_check(tp->md5sig_info,
929 lockdep_sock_is_held(sk));
930 if (!md5sig)
931 return NULL;
932
933 hlist_for_each_entry_rcu(key, &md5sig->head, node) {
934 if (key->family != family)
935 continue;
936
937 if (family == AF_INET) {
938 mask = inet_make_mask(key->prefixlen);
939 match = (key->addr.a4.s_addr & mask) ==
940 (addr->a4.s_addr & mask);
941#if IS_ENABLED(CONFIG_IPV6)
942 } else if (family == AF_INET6) {
943 match = ipv6_prefix_equal(&key->addr.a6, &addr->a6,
944 key->prefixlen);
945#endif
946 } else {
947 match = false;
948 }
949
950 if (match && (!best_match ||
951 key->prefixlen > best_match->prefixlen))
952 best_match = key;
953 }
954 return best_match;
955}
956EXPORT_SYMBOL(tcp_md5_do_lookup);
957
958static struct tcp_md5sig_key *tcp_md5_do_lookup_exact(const struct sock *sk,
959 const union tcp_md5_addr *addr,
960 int family, u8 prefixlen)
961{
962 const struct tcp_sock *tp = tcp_sk(sk);
963 struct tcp_md5sig_key *key;
964 unsigned int size = sizeof(struct in_addr);
965 const struct tcp_md5sig_info *md5sig;
966
967 /* caller either holds rcu_read_lock() or socket lock */
968 md5sig = rcu_dereference_check(tp->md5sig_info,
969 lockdep_sock_is_held(sk));
970 if (!md5sig)
971 return NULL;
972#if IS_ENABLED(CONFIG_IPV6)
973 if (family == AF_INET6)
974 size = sizeof(struct in6_addr);
975#endif
976 hlist_for_each_entry_rcu(key, &md5sig->head, node) {
977 if (key->family != family)
978 continue;
979 if (!memcmp(&key->addr, addr, size) &&
980 key->prefixlen == prefixlen)
981 return key;
982 }
983 return NULL;
984}
985
986struct tcp_md5sig_key *tcp_v4_md5_lookup(const struct sock *sk,
987 const struct sock *addr_sk)
988{
989 const union tcp_md5_addr *addr;
990
991 addr = (const union tcp_md5_addr *)&addr_sk->sk_daddr;
992 return tcp_md5_do_lookup(sk, addr, AF_INET);
993}
994EXPORT_SYMBOL(tcp_v4_md5_lookup);
995
996/* This can be called on a newly created socket, from other files */
997int tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr,
998 int family, u8 prefixlen, const u8 *newkey, u8 newkeylen,
999 gfp_t gfp)
1000{
1001 /* Add Key to the list */
1002 struct tcp_md5sig_key *key;
1003 struct tcp_sock *tp = tcp_sk(sk);
1004 struct tcp_md5sig_info *md5sig;
1005
1006 key = tcp_md5_do_lookup_exact(sk, addr, family, prefixlen);
1007 if (key) {
1008 /* Pre-existing entry - just update that one. */
1009 memcpy(key->key, newkey, newkeylen);
1010 key->keylen = newkeylen;
1011 return 0;
1012 }
1013
1014 md5sig = rcu_dereference_protected(tp->md5sig_info,
1015 lockdep_sock_is_held(sk));
1016 if (!md5sig) {
1017 md5sig = kmalloc(sizeof(*md5sig), gfp);
1018 if (!md5sig)
1019 return -ENOMEM;
1020
1021 sk_nocaps_add(sk, NETIF_F_GSO_MASK);
1022 INIT_HLIST_HEAD(&md5sig->head);
1023 rcu_assign_pointer(tp->md5sig_info, md5sig);
1024 }
1025
1026 key = sock_kmalloc(sk, sizeof(*key), gfp);
1027 if (!key)
1028 return -ENOMEM;
1029 if (!tcp_alloc_md5sig_pool()) {
1030 sock_kfree_s(sk, key, sizeof(*key));
1031 return -ENOMEM;
1032 }
1033
1034 memcpy(key->key, newkey, newkeylen);
1035 key->keylen = newkeylen;
1036 key->family = family;
1037 key->prefixlen = prefixlen;
1038 memcpy(&key->addr, addr,
1039 (family == AF_INET6) ? sizeof(struct in6_addr) :
1040 sizeof(struct in_addr));
1041 hlist_add_head_rcu(&key->node, &md5sig->head);
1042 return 0;
1043}
1044EXPORT_SYMBOL(tcp_md5_do_add);
1045
1046int tcp_md5_do_del(struct sock *sk, const union tcp_md5_addr *addr, int family,
1047 u8 prefixlen)
1048{
1049 struct tcp_md5sig_key *key;
1050
1051 key = tcp_md5_do_lookup_exact(sk, addr, family, prefixlen);
1052 if (!key)
1053 return -ENOENT;
1054 hlist_del_rcu(&key->node);
1055 atomic_sub(sizeof(*key), &sk->sk_omem_alloc);
1056 kfree_rcu(key, rcu);
1057 return 0;
1058}
1059EXPORT_SYMBOL(tcp_md5_do_del);
1060
1061static void tcp_clear_md5_list(struct sock *sk)
1062{
1063 struct tcp_sock *tp = tcp_sk(sk);
1064 struct tcp_md5sig_key *key;
1065 struct hlist_node *n;
1066 struct tcp_md5sig_info *md5sig;
1067
1068 md5sig = rcu_dereference_protected(tp->md5sig_info, 1);
1069
1070 hlist_for_each_entry_safe(key, n, &md5sig->head, node) {
1071 hlist_del_rcu(&key->node);
1072 atomic_sub(sizeof(*key), &sk->sk_omem_alloc);
1073 kfree_rcu(key, rcu);
1074 }
1075}
1076
1077static int tcp_v4_parse_md5_keys(struct sock *sk, int optname,
1078 char __user *optval, int optlen)
1079{
1080 struct tcp_md5sig cmd;
1081 struct sockaddr_in *sin = (struct sockaddr_in *)&cmd.tcpm_addr;
1082 u8 prefixlen = 32;
1083
1084 if (optlen < sizeof(cmd))
1085 return -EINVAL;
1086
1087 if (copy_from_user(&cmd, optval, sizeof(cmd)))
1088 return -EFAULT;
1089
1090 if (sin->sin_family != AF_INET)
1091 return -EINVAL;
1092
1093 if (optname == TCP_MD5SIG_EXT &&
1094 cmd.tcpm_flags & TCP_MD5SIG_FLAG_PREFIX) {
1095 prefixlen = cmd.tcpm_prefixlen;
1096 if (prefixlen > 32)
1097 return -EINVAL;
1098 }
1099
1100 if (!cmd.tcpm_keylen)
1101 return tcp_md5_do_del(sk, (union tcp_md5_addr *)&sin->sin_addr.s_addr,
1102 AF_INET, prefixlen);
1103
1104 if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN)
1105 return -EINVAL;
1106
1107 return tcp_md5_do_add(sk, (union tcp_md5_addr *)&sin->sin_addr.s_addr,
1108 AF_INET, prefixlen, cmd.tcpm_key, cmd.tcpm_keylen,
1109 GFP_KERNEL);
1110}
1111
1112static int tcp_v4_md5_hash_headers(struct tcp_md5sig_pool *hp,
1113 __be32 daddr, __be32 saddr,
1114 const struct tcphdr *th, int nbytes)
1115{
1116 struct tcp4_pseudohdr *bp;
1117 struct scatterlist sg;
1118 struct tcphdr *_th;
1119
1120 bp = hp->scratch;
1121 bp->saddr = saddr;
1122 bp->daddr = daddr;
1123 bp->pad = 0;
1124 bp->protocol = IPPROTO_TCP;
1125 bp->len = cpu_to_be16(nbytes);
1126
1127 _th = (struct tcphdr *)(bp + 1);
1128 memcpy(_th, th, sizeof(*th));
1129 _th->check = 0;
1130
1131 sg_init_one(&sg, bp, sizeof(*bp) + sizeof(*th));
1132 ahash_request_set_crypt(hp->md5_req, &sg, NULL,
1133 sizeof(*bp) + sizeof(*th));
1134 return crypto_ahash_update(hp->md5_req);
1135}
1136
1137static int tcp_v4_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key,
1138 __be32 daddr, __be32 saddr, const struct tcphdr *th)
1139{
1140 struct tcp_md5sig_pool *hp;
1141 struct ahash_request *req;
1142
1143 hp = tcp_get_md5sig_pool();
1144 if (!hp)
1145 goto clear_hash_noput;
1146 req = hp->md5_req;
1147
1148 if (crypto_ahash_init(req))
1149 goto clear_hash;
1150 if (tcp_v4_md5_hash_headers(hp, daddr, saddr, th, th->doff << 2))
1151 goto clear_hash;
1152 if (tcp_md5_hash_key(hp, key))
1153 goto clear_hash;
1154 ahash_request_set_crypt(req, NULL, md5_hash, 0);
1155 if (crypto_ahash_final(req))
1156 goto clear_hash;
1157
1158 tcp_put_md5sig_pool();
1159 return 0;
1160
1161clear_hash:
1162 tcp_put_md5sig_pool();
1163clear_hash_noput:
1164 memset(md5_hash, 0, 16);
1165 return 1;
1166}
1167
1168int tcp_v4_md5_hash_skb(char *md5_hash, const struct tcp_md5sig_key *key,
1169 const struct sock *sk,
1170 const struct sk_buff *skb)
1171{
1172 struct tcp_md5sig_pool *hp;
1173 struct ahash_request *req;
1174 const struct tcphdr *th = tcp_hdr(skb);
1175 __be32 saddr, daddr;
1176
1177 if (sk) { /* valid for establish/request sockets */
1178 saddr = sk->sk_rcv_saddr;
1179 daddr = sk->sk_daddr;
1180 } else {
1181 const struct iphdr *iph = ip_hdr(skb);
1182 saddr = iph->saddr;
1183 daddr = iph->daddr;
1184 }
1185
1186 hp = tcp_get_md5sig_pool();
1187 if (!hp)
1188 goto clear_hash_noput;
1189 req = hp->md5_req;
1190
1191 if (crypto_ahash_init(req))
1192 goto clear_hash;
1193
1194 if (tcp_v4_md5_hash_headers(hp, daddr, saddr, th, skb->len))
1195 goto clear_hash;
1196 if (tcp_md5_hash_skb_data(hp, skb, th->doff << 2))
1197 goto clear_hash;
1198 if (tcp_md5_hash_key(hp, key))
1199 goto clear_hash;
1200 ahash_request_set_crypt(req, NULL, md5_hash, 0);
1201 if (crypto_ahash_final(req))
1202 goto clear_hash;
1203
1204 tcp_put_md5sig_pool();
1205 return 0;
1206
1207clear_hash:
1208 tcp_put_md5sig_pool();
1209clear_hash_noput:
1210 memset(md5_hash, 0, 16);
1211 return 1;
1212}
1213EXPORT_SYMBOL(tcp_v4_md5_hash_skb);
1214
1215#endif
1216
1217/* Called with rcu_read_lock() */
1218static bool tcp_v4_inbound_md5_hash(const struct sock *sk,
1219 const struct sk_buff *skb)
1220{
1221#ifdef CONFIG_TCP_MD5SIG
1222 /*
1223 * This gets called for each TCP segment that arrives
1224 * so we want to be efficient.
1225 * We have 3 drop cases:
1226 * o No MD5 hash and one expected.
1227 * o MD5 hash and we're not expecting one.
1228 * o MD5 hash and its wrong.
1229 */
1230 const __u8 *hash_location = NULL;
1231 struct tcp_md5sig_key *hash_expected;
1232 const struct iphdr *iph = ip_hdr(skb);
1233 const struct tcphdr *th = tcp_hdr(skb);
1234 int genhash;
1235 unsigned char newhash[16];
1236
1237 hash_expected = tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&iph->saddr,
1238 AF_INET);
1239 hash_location = tcp_parse_md5sig_option(th);
1240
1241 /* We've parsed the options - do we have a hash? */
1242 if (!hash_expected && !hash_location)
1243 return false;
1244
1245 if (hash_expected && !hash_location) {
1246 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5NOTFOUND);
1247 return true;
1248 }
1249
1250 if (!hash_expected && hash_location) {
1251 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5UNEXPECTED);
1252 return true;
1253 }
1254
1255 /* Okay, so this is hash_expected and hash_location -
1256 * so we need to calculate the checksum.
1257 */
1258 genhash = tcp_v4_md5_hash_skb(newhash,
1259 hash_expected,
1260 NULL, skb);
1261
1262 if (genhash || memcmp(hash_location, newhash, 16) != 0) {
1263 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5FAILURE);
1264 net_info_ratelimited("MD5 Hash failed for (%pI4, %d)->(%pI4, %d)%s\n",
1265 &iph->saddr, ntohs(th->source),
1266 &iph->daddr, ntohs(th->dest),
1267 genhash ? " tcp_v4_calc_md5_hash failed"
1268 : "");
1269 return true;
1270 }
1271 return false;
1272#endif
1273 return false;
1274}
1275
1276static void tcp_v4_init_req(struct request_sock *req,
1277 const struct sock *sk_listener,
1278 struct sk_buff *skb)
1279{
1280 struct inet_request_sock *ireq = inet_rsk(req);
1281 struct net *net = sock_net(sk_listener);
1282
1283 sk_rcv_saddr_set(req_to_sk(req), ip_hdr(skb)->daddr);
1284 sk_daddr_set(req_to_sk(req), ip_hdr(skb)->saddr);
1285 RCU_INIT_POINTER(ireq->ireq_opt, tcp_v4_save_options(net, skb));
1286}
1287
1288static struct dst_entry *tcp_v4_route_req(const struct sock *sk,
1289 struct flowi *fl,
1290 const struct request_sock *req)
1291{
1292 return inet_csk_route_req(sk, &fl->u.ip4, req);
1293}
1294
1295struct request_sock_ops tcp_request_sock_ops __read_mostly = {
1296 .family = PF_INET,
1297 .obj_size = sizeof(struct tcp_request_sock),
1298 .rtx_syn_ack = tcp_rtx_synack,
1299 .send_ack = tcp_v4_reqsk_send_ack,
1300 .destructor = tcp_v4_reqsk_destructor,
1301 .send_reset = tcp_v4_send_reset,
1302 .syn_ack_timeout = tcp_syn_ack_timeout,
1303};
1304
1305static const struct tcp_request_sock_ops tcp_request_sock_ipv4_ops = {
1306 .mss_clamp = TCP_MSS_DEFAULT,
1307#ifdef CONFIG_TCP_MD5SIG
1308 .req_md5_lookup = tcp_v4_md5_lookup,
1309 .calc_md5_hash = tcp_v4_md5_hash_skb,
1310#endif
1311 .init_req = tcp_v4_init_req,
1312#ifdef CONFIG_SYN_COOKIES
1313 .cookie_init_seq = cookie_v4_init_sequence,
1314#endif
1315 .route_req = tcp_v4_route_req,
1316 .init_seq = tcp_v4_init_seq,
1317 .init_ts_off = tcp_v4_init_ts_off,
1318 .send_synack = tcp_v4_send_synack,
1319};
1320
1321int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
1322{
1323 /* Never answer to SYNs send to broadcast or multicast */
1324 if (skb_rtable(skb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
1325 goto drop;
1326
1327 return tcp_conn_request(&tcp_request_sock_ops,
1328 &tcp_request_sock_ipv4_ops, sk, skb);
1329
1330drop:
1331 tcp_listendrop(sk);
1332 return 0;
1333}
1334EXPORT_SYMBOL(tcp_v4_conn_request);
1335
1336
1337/*
1338 * The three way handshake has completed - we got a valid synack -
1339 * now create the new socket.
1340 */
1341struct sock *tcp_v4_syn_recv_sock(const struct sock *sk, struct sk_buff *skb,
1342 struct request_sock *req,
1343 struct dst_entry *dst,
1344 struct request_sock *req_unhash,
1345 bool *own_req)
1346{
1347 struct inet_request_sock *ireq;
1348 struct inet_sock *newinet;
1349 struct tcp_sock *newtp;
1350 struct sock *newsk;
1351#ifdef CONFIG_TCP_MD5SIG
1352 struct tcp_md5sig_key *key;
1353#endif
1354 struct ip_options_rcu *inet_opt;
1355
1356 if (sk_acceptq_is_full(sk))
1357 goto exit_overflow;
1358
1359 newsk = tcp_create_openreq_child(sk, req, skb);
1360 if (!newsk)
1361 goto exit_nonewsk;
1362
1363 newsk->sk_gso_type = SKB_GSO_TCPV4;
1364 inet_sk_rx_dst_set(newsk, skb);
1365
1366 newtp = tcp_sk(newsk);
1367 newinet = inet_sk(newsk);
1368 ireq = inet_rsk(req);
1369 sk_daddr_set(newsk, ireq->ir_rmt_addr);
1370 sk_rcv_saddr_set(newsk, ireq->ir_loc_addr);
1371 newsk->sk_bound_dev_if = ireq->ir_iif;
1372 newinet->inet_saddr = ireq->ir_loc_addr;
1373 inet_opt = rcu_dereference(ireq->ireq_opt);
1374 RCU_INIT_POINTER(newinet->inet_opt, inet_opt);
1375 newinet->mc_index = inet_iif(skb);
1376 newinet->mc_ttl = ip_hdr(skb)->ttl;
1377 newinet->rcv_tos = ip_hdr(skb)->tos;
1378 inet_csk(newsk)->icsk_ext_hdr_len = 0;
1379 if (inet_opt)
1380 inet_csk(newsk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
1381 newinet->inet_id = newtp->write_seq ^ jiffies;
1382
1383 if (!dst) {
1384 dst = inet_csk_route_child_sock(sk, newsk, req);
1385 if (!dst)
1386 goto put_and_exit;
1387 } else {
1388 /* syncookie case : see end of cookie_v4_check() */
1389 }
1390 sk_setup_caps(newsk, dst);
1391
1392 tcp_ca_openreq_child(newsk, dst);
1393
1394 tcp_sync_mss(newsk, dst_mtu(dst));
1395 newtp->advmss = tcp_mss_clamp(tcp_sk(sk), dst_metric_advmss(dst));
1396
1397 tcp_initialize_rcv_mss(newsk);
1398
1399#ifdef CONFIG_TCP_MD5SIG
1400 /* Copy over the MD5 key from the original socket */
1401 key = tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&newinet->inet_daddr,
1402 AF_INET);
1403 if (key) {
1404 /*
1405 * We're using one, so create a matching key
1406 * on the newsk structure. If we fail to get
1407 * memory, then we end up not copying the key
1408 * across. Shucks.
1409 */
1410 tcp_md5_do_add(newsk, (union tcp_md5_addr *)&newinet->inet_daddr,
1411 AF_INET, 32, key->key, key->keylen, GFP_ATOMIC);
1412 sk_nocaps_add(newsk, NETIF_F_GSO_MASK);
1413 }
1414#endif
1415
1416 if (__inet_inherit_port(sk, newsk) < 0)
1417 goto put_and_exit;
1418 *own_req = inet_ehash_nolisten(newsk, req_to_sk(req_unhash));
1419 if (likely(*own_req)) {
1420 tcp_move_syn(newtp, req);
1421 ireq->ireq_opt = NULL;
1422 } else {
1423 newinet->inet_opt = NULL;
1424 }
1425 return newsk;
1426
1427exit_overflow:
1428 NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
1429exit_nonewsk:
1430 dst_release(dst);
1431exit:
1432 tcp_listendrop(sk);
1433 return NULL;
1434put_and_exit:
1435 newinet->inet_opt = NULL;
1436 inet_csk_prepare_forced_close(newsk);
1437 tcp_done(newsk);
1438 goto exit;
1439}
1440EXPORT_SYMBOL(tcp_v4_syn_recv_sock);
1441
1442static struct sock *tcp_v4_cookie_check(struct sock *sk, struct sk_buff *skb)
1443{
1444#ifdef CONFIG_SYN_COOKIES
1445 const struct tcphdr *th = tcp_hdr(skb);
1446
1447 if (!th->syn)
1448 sk = cookie_v4_check(sk, skb);
1449#endif
1450 return sk;
1451}
1452
1453/* The socket must have it's spinlock held when we get
1454 * here, unless it is a TCP_LISTEN socket.
1455 *
1456 * We have a potential double-lock case here, so even when
1457 * doing backlog processing we use the BH locking scheme.
1458 * This is because we cannot sleep with the original spinlock
1459 * held.
1460 */
1461int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
1462{
1463 struct sock *rsk;
1464
1465 if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
1466 struct dst_entry *dst = sk->sk_rx_dst;
1467
1468 sock_rps_save_rxhash(sk, skb);
1469 sk_mark_napi_id(sk, skb);
1470 if (dst) {
1471 if (inet_sk(sk)->rx_dst_ifindex != skb->skb_iif ||
1472 !dst->ops->check(dst, 0)) {
1473 dst_release(dst);
1474 sk->sk_rx_dst = NULL;
1475 }
1476 }
1477 tcp_rcv_established(sk, skb, tcp_hdr(skb));
1478 return 0;
1479 }
1480
1481 if (tcp_checksum_complete(skb))
1482 goto csum_err;
1483
1484 if (sk->sk_state == TCP_LISTEN) {
1485 struct sock *nsk = tcp_v4_cookie_check(sk, skb);
1486
1487 if (!nsk)
1488 goto discard;
1489 if (nsk != sk) {
1490 if (tcp_child_process(sk, nsk, skb)) {
1491 rsk = nsk;
1492 goto reset;
1493 }
1494 return 0;
1495 }
1496 } else
1497 sock_rps_save_rxhash(sk, skb);
1498
1499 if (tcp_rcv_state_process(sk, skb)) {
1500 rsk = sk;
1501 goto reset;
1502 }
1503 return 0;
1504
1505reset:
1506 tcp_v4_send_reset(rsk, skb);
1507discard:
1508 kfree_skb(skb);
1509 /* Be careful here. If this function gets more complicated and
1510 * gcc suffers from register pressure on the x86, sk (in %ebx)
1511 * might be destroyed here. This current version compiles correctly,
1512 * but you have been warned.
1513 */
1514 return 0;
1515
1516csum_err:
1517 TCP_INC_STATS(sock_net(sk), TCP_MIB_CSUMERRORS);
1518 TCP_INC_STATS(sock_net(sk), TCP_MIB_INERRS);
1519 goto discard;
1520}
1521EXPORT_SYMBOL(tcp_v4_do_rcv);
1522
1523int tcp_v4_early_demux(struct sk_buff *skb)
1524{
1525 const struct iphdr *iph;
1526 const struct tcphdr *th;
1527 struct sock *sk;
1528
1529 if (skb->pkt_type != PACKET_HOST)
1530 return 0;
1531
1532 if (!pskb_may_pull(skb, skb_transport_offset(skb) + sizeof(struct tcphdr)))
1533 return 0;
1534
1535 iph = ip_hdr(skb);
1536 th = tcp_hdr(skb);
1537
1538 if (th->doff < sizeof(struct tcphdr) / 4)
1539 return 0;
1540
1541 sk = __inet_lookup_established(dev_net(skb->dev), &tcp_hashinfo,
1542 iph->saddr, th->source,
1543 iph->daddr, ntohs(th->dest),
1544 skb->skb_iif, inet_sdif(skb));
1545 if (sk) {
1546 skb->sk = sk;
1547 skb->destructor = sock_edemux;
1548 if (sk_fullsock(sk)) {
1549 struct dst_entry *dst = READ_ONCE(sk->sk_rx_dst);
1550
1551 if (dst)
1552 dst = dst_check(dst, 0);
1553 if (dst &&
1554 inet_sk(sk)->rx_dst_ifindex == skb->skb_iif)
1555 skb_dst_set_noref(skb, dst);
1556 }
1557 }
1558 return 0;
1559}
1560
1561bool tcp_add_backlog(struct sock *sk, struct sk_buff *skb)
1562{
1563 u32 limit = sk->sk_rcvbuf + sk->sk_sndbuf;
1564
1565 /* Only socket owner can try to collapse/prune rx queues
1566 * to reduce memory overhead, so add a little headroom here.
1567 * Few sockets backlog are possibly concurrently non empty.
1568 */
1569 limit += 64*1024;
1570
1571 /* In case all data was pulled from skb frags (in __pskb_pull_tail()),
1572 * we can fix skb->truesize to its real value to avoid future drops.
1573 * This is valid because skb is not yet charged to the socket.
1574 * It has been noticed pure SACK packets were sometimes dropped
1575 * (if cooked by drivers without copybreak feature).
1576 */
1577 skb_condense(skb);
1578
1579 if (unlikely(sk_add_backlog(sk, skb, limit))) {
1580 bh_unlock_sock(sk);
1581 __NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPBACKLOGDROP);
1582 return true;
1583 }
1584 return false;
1585}
1586EXPORT_SYMBOL(tcp_add_backlog);
1587
1588int tcp_filter(struct sock *sk, struct sk_buff *skb)
1589{
1590 struct tcphdr *th = (struct tcphdr *)skb->data;
1591 unsigned int eaten = skb->len;
1592 int err;
1593
1594 err = sk_filter_trim_cap(sk, skb, th->doff * 4);
1595 if (!err) {
1596 eaten -= skb->len;
1597 TCP_SKB_CB(skb)->end_seq -= eaten;
1598 }
1599 return err;
1600}
1601EXPORT_SYMBOL(tcp_filter);
1602
1603static void tcp_v4_restore_cb(struct sk_buff *skb)
1604{
1605 memmove(IPCB(skb), &TCP_SKB_CB(skb)->header.h4,
1606 sizeof(struct inet_skb_parm));
1607}
1608
1609static void tcp_v4_fill_cb(struct sk_buff *skb, const struct iphdr *iph,
1610 const struct tcphdr *th)
1611{
1612 /* This is tricky : We move IPCB at its correct location into TCP_SKB_CB()
1613 * barrier() makes sure compiler wont play fool^Waliasing games.
1614 */
1615 memmove(&TCP_SKB_CB(skb)->header.h4, IPCB(skb),
1616 sizeof(struct inet_skb_parm));
1617 barrier();
1618
1619 TCP_SKB_CB(skb)->seq = ntohl(th->seq);
1620 TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
1621 skb->len - th->doff * 4);
1622 TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
1623 TCP_SKB_CB(skb)->tcp_flags = tcp_flag_byte(th);
1624 TCP_SKB_CB(skb)->tcp_tw_isn = 0;
1625 TCP_SKB_CB(skb)->ip_dsfield = ipv4_get_dsfield(iph);
1626 TCP_SKB_CB(skb)->sacked = 0;
1627 TCP_SKB_CB(skb)->has_rxtstamp =
1628 skb->tstamp || skb_hwtstamps(skb)->hwtstamp;
1629}
1630
1631/*
1632 * From tcp_input.c
1633 */
1634
1635int tcp_v4_rcv(struct sk_buff *skb)
1636{
1637 struct net *net = dev_net(skb->dev);
1638 int sdif = inet_sdif(skb);
1639 const struct iphdr *iph;
1640 const struct tcphdr *th;
1641 bool refcounted;
1642 struct sock *sk;
1643 int ret;
1644
1645 if (skb->pkt_type != PACKET_HOST)
1646 goto discard_it;
1647
1648 /* Count it even if it's bad */
1649 __TCP_INC_STATS(net, TCP_MIB_INSEGS);
1650
1651 if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
1652 goto discard_it;
1653
1654 th = (const struct tcphdr *)skb->data;
1655
1656 if (unlikely(th->doff < sizeof(struct tcphdr) / 4))
1657 goto bad_packet;
1658 if (!pskb_may_pull(skb, th->doff * 4))
1659 goto discard_it;
1660
1661 /* An explanation is required here, I think.
1662 * Packet length and doff are validated by header prediction,
1663 * provided case of th->doff==0 is eliminated.
1664 * So, we defer the checks. */
1665
1666 if (skb_checksum_init(skb, IPPROTO_TCP, inet_compute_pseudo))
1667 goto csum_error;
1668
1669 th = (const struct tcphdr *)skb->data;
1670 iph = ip_hdr(skb);
1671lookup:
1672 sk = __inet_lookup_skb(&tcp_hashinfo, skb, __tcp_hdrlen(th), th->source,
1673 th->dest, sdif, &refcounted);
1674 if (!sk)
1675 goto no_tcp_socket;
1676
1677process:
1678 if (sk->sk_state == TCP_TIME_WAIT)
1679 goto do_time_wait;
1680
1681 if (sk->sk_state == TCP_NEW_SYN_RECV) {
1682 struct request_sock *req = inet_reqsk(sk);
1683 bool req_stolen = false;
1684 struct sock *nsk;
1685
1686 sk = req->rsk_listener;
1687 if (unlikely(tcp_v4_inbound_md5_hash(sk, skb))) {
1688 sk_drops_add(sk, skb);
1689 reqsk_put(req);
1690 goto discard_it;
1691 }
1692 if (unlikely(sk->sk_state != TCP_LISTEN)) {
1693 inet_csk_reqsk_queue_drop_and_put(sk, req);
1694 goto lookup;
1695 }
1696 /* We own a reference on the listener, increase it again
1697 * as we might lose it too soon.
1698 */
1699 sock_hold(sk);
1700 refcounted = true;
1701 nsk = NULL;
1702 if (!tcp_filter(sk, skb)) {
1703 th = (const struct tcphdr *)skb->data;
1704 iph = ip_hdr(skb);
1705 tcp_v4_fill_cb(skb, iph, th);
1706 nsk = tcp_check_req(sk, skb, req, false, &req_stolen);
1707 }
1708 if (!nsk) {
1709 reqsk_put(req);
1710 if (req_stolen) {
1711 /* Another cpu got exclusive access to req
1712 * and created a full blown socket.
1713 * Try to feed this packet to this socket
1714 * instead of discarding it.
1715 */
1716 tcp_v4_restore_cb(skb);
1717 sock_put(sk);
1718 goto lookup;
1719 }
1720 goto discard_and_relse;
1721 }
1722 if (nsk == sk) {
1723 reqsk_put(req);
1724 tcp_v4_restore_cb(skb);
1725 } else if (tcp_child_process(sk, nsk, skb)) {
1726 tcp_v4_send_reset(nsk, skb);
1727 goto discard_and_relse;
1728 } else {
1729 sock_put(sk);
1730 return 0;
1731 }
1732 }
1733 if (unlikely(iph->ttl < inet_sk(sk)->min_ttl)) {
1734 __NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP);
1735 goto discard_and_relse;
1736 }
1737
1738 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
1739 goto discard_and_relse;
1740
1741 if (tcp_v4_inbound_md5_hash(sk, skb))
1742 goto discard_and_relse;
1743
1744 nf_reset(skb);
1745
1746 if (tcp_filter(sk, skb))
1747 goto discard_and_relse;
1748 th = (const struct tcphdr *)skb->data;
1749 iph = ip_hdr(skb);
1750 tcp_v4_fill_cb(skb, iph, th);
1751
1752 skb->dev = NULL;
1753
1754 if (sk->sk_state == TCP_LISTEN) {
1755 ret = tcp_v4_do_rcv(sk, skb);
1756 goto put_and_return;
1757 }
1758
1759 sk_incoming_cpu_update(sk);
1760
1761 bh_lock_sock_nested(sk);
1762 tcp_segs_in(tcp_sk(sk), skb);
1763 ret = 0;
1764 if (!sock_owned_by_user(sk)) {
1765 ret = tcp_v4_do_rcv(sk, skb);
1766 } else if (tcp_add_backlog(sk, skb)) {
1767 goto discard_and_relse;
1768 }
1769 bh_unlock_sock(sk);
1770
1771put_and_return:
1772 if (refcounted)
1773 sock_put(sk);
1774
1775 return ret;
1776
1777no_tcp_socket:
1778 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
1779 goto discard_it;
1780
1781 tcp_v4_fill_cb(skb, iph, th);
1782
1783 if (tcp_checksum_complete(skb)) {
1784csum_error:
1785 __TCP_INC_STATS(net, TCP_MIB_CSUMERRORS);
1786bad_packet:
1787 __TCP_INC_STATS(net, TCP_MIB_INERRS);
1788 } else {
1789 tcp_v4_send_reset(NULL, skb);
1790 }
1791
1792discard_it:
1793 /* Discard frame. */
1794 kfree_skb(skb);
1795 return 0;
1796
1797discard_and_relse:
1798 sk_drops_add(sk, skb);
1799 if (refcounted)
1800 sock_put(sk);
1801 goto discard_it;
1802
1803do_time_wait:
1804 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
1805 inet_twsk_put(inet_twsk(sk));
1806 goto discard_it;
1807 }
1808
1809 tcp_v4_fill_cb(skb, iph, th);
1810
1811 if (tcp_checksum_complete(skb)) {
1812 inet_twsk_put(inet_twsk(sk));
1813 goto csum_error;
1814 }
1815 switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) {
1816 case TCP_TW_SYN: {
1817 struct sock *sk2 = inet_lookup_listener(dev_net(skb->dev),
1818 &tcp_hashinfo, skb,
1819 __tcp_hdrlen(th),
1820 iph->saddr, th->source,
1821 iph->daddr, th->dest,
1822 inet_iif(skb),
1823 sdif);
1824 if (sk2) {
1825 inet_twsk_deschedule_put(inet_twsk(sk));
1826 sk = sk2;
1827 tcp_v4_restore_cb(skb);
1828 refcounted = false;
1829 goto process;
1830 }
1831 }
1832 /* to ACK */
1833 /* fall through */
1834 case TCP_TW_ACK:
1835 tcp_v4_timewait_ack(sk, skb);
1836 break;
1837 case TCP_TW_RST:
1838 tcp_v4_send_reset(sk, skb);
1839 inet_twsk_deschedule_put(inet_twsk(sk));
1840 goto discard_it;
1841 case TCP_TW_SUCCESS:;
1842 }
1843 goto discard_it;
1844}
1845
1846static struct timewait_sock_ops tcp_timewait_sock_ops = {
1847 .twsk_obj_size = sizeof(struct tcp_timewait_sock),
1848 .twsk_unique = tcp_twsk_unique,
1849 .twsk_destructor= tcp_twsk_destructor,
1850};
1851
1852void inet_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb)
1853{
1854 struct dst_entry *dst = skb_dst(skb);
1855
1856 if (dst && dst_hold_safe(dst)) {
1857 sk->sk_rx_dst = dst;
1858 inet_sk(sk)->rx_dst_ifindex = skb->skb_iif;
1859 }
1860}
1861EXPORT_SYMBOL(inet_sk_rx_dst_set);
1862
1863const struct inet_connection_sock_af_ops ipv4_specific = {
1864 .queue_xmit = ip_queue_xmit,
1865 .send_check = tcp_v4_send_check,
1866 .rebuild_header = inet_sk_rebuild_header,
1867 .sk_rx_dst_set = inet_sk_rx_dst_set,
1868 .conn_request = tcp_v4_conn_request,
1869 .syn_recv_sock = tcp_v4_syn_recv_sock,
1870 .net_header_len = sizeof(struct iphdr),
1871 .setsockopt = ip_setsockopt,
1872 .getsockopt = ip_getsockopt,
1873 .addr2sockaddr = inet_csk_addr2sockaddr,
1874 .sockaddr_len = sizeof(struct sockaddr_in),
1875#ifdef CONFIG_COMPAT
1876 .compat_setsockopt = compat_ip_setsockopt,
1877 .compat_getsockopt = compat_ip_getsockopt,
1878#endif
1879 .mtu_reduced = tcp_v4_mtu_reduced,
1880};
1881EXPORT_SYMBOL(ipv4_specific);
1882
1883#ifdef CONFIG_TCP_MD5SIG
1884static const struct tcp_sock_af_ops tcp_sock_ipv4_specific = {
1885 .md5_lookup = tcp_v4_md5_lookup,
1886 .calc_md5_hash = tcp_v4_md5_hash_skb,
1887 .md5_parse = tcp_v4_parse_md5_keys,
1888};
1889#endif
1890
1891/* NOTE: A lot of things set to zero explicitly by call to
1892 * sk_alloc() so need not be done here.
1893 */
1894static int tcp_v4_init_sock(struct sock *sk)
1895{
1896 struct inet_connection_sock *icsk = inet_csk(sk);
1897
1898 tcp_init_sock(sk);
1899
1900 icsk->icsk_af_ops = &ipv4_specific;
1901
1902#ifdef CONFIG_TCP_MD5SIG
1903 tcp_sk(sk)->af_specific = &tcp_sock_ipv4_specific;
1904#endif
1905
1906 return 0;
1907}
1908
1909void tcp_v4_destroy_sock(struct sock *sk)
1910{
1911 struct tcp_sock *tp = tcp_sk(sk);
1912
1913 trace_tcp_destroy_sock(sk);
1914
1915 tcp_clear_xmit_timers(sk);
1916
1917 tcp_cleanup_congestion_control(sk);
1918
1919 tcp_cleanup_ulp(sk);
1920
1921 /* Cleanup up the write buffer. */
1922 tcp_write_queue_purge(sk);
1923
1924 /* Check if we want to disable active TFO */
1925 tcp_fastopen_active_disable_ofo_check(sk);
1926
1927 /* Cleans up our, hopefully empty, out_of_order_queue. */
1928 skb_rbtree_purge(&tp->out_of_order_queue);
1929
1930#ifdef CONFIG_TCP_MD5SIG
1931 /* Clean up the MD5 key list, if any */
1932 if (tp->md5sig_info) {
1933 tcp_clear_md5_list(sk);
1934 kfree_rcu(rcu_dereference_protected(tp->md5sig_info, 1), rcu);
1935 tp->md5sig_info = NULL;
1936 }
1937#endif
1938
1939 /* Clean up a referenced TCP bind bucket. */
1940 if (inet_csk(sk)->icsk_bind_hash)
1941 inet_put_port(sk);
1942
1943 BUG_ON(tp->fastopen_rsk);
1944
1945 /* If socket is aborted during connect operation */
1946 tcp_free_fastopen_req(tp);
1947 tcp_fastopen_destroy_cipher(sk);
1948 tcp_saved_syn_free(tp);
1949
1950 sk_sockets_allocated_dec(sk);
1951}
1952EXPORT_SYMBOL(tcp_v4_destroy_sock);
1953
1954#ifdef CONFIG_PROC_FS
1955/* Proc filesystem TCP sock list dumping. */
1956
1957/*
1958 * Get next listener socket follow cur. If cur is NULL, get first socket
1959 * starting from bucket given in st->bucket; when st->bucket is zero the
1960 * very first socket in the hash table is returned.
1961 */
1962static void *listening_get_next(struct seq_file *seq, void *cur)
1963{
1964 struct tcp_iter_state *st = seq->private;
1965 struct net *net = seq_file_net(seq);
1966 struct inet_listen_hashbucket *ilb;
1967 struct sock *sk = cur;
1968
1969 if (!sk) {
1970get_head:
1971 ilb = &tcp_hashinfo.listening_hash[st->bucket];
1972 spin_lock(&ilb->lock);
1973 sk = sk_head(&ilb->head);
1974 st->offset = 0;
1975 goto get_sk;
1976 }
1977 ilb = &tcp_hashinfo.listening_hash[st->bucket];
1978 ++st->num;
1979 ++st->offset;
1980
1981 sk = sk_next(sk);
1982get_sk:
1983 sk_for_each_from(sk) {
1984 if (!net_eq(sock_net(sk), net))
1985 continue;
1986 if (sk->sk_family == st->family)
1987 return sk;
1988 }
1989 spin_unlock(&ilb->lock);
1990 st->offset = 0;
1991 if (++st->bucket < INET_LHTABLE_SIZE)
1992 goto get_head;
1993 return NULL;
1994}
1995
1996static void *listening_get_idx(struct seq_file *seq, loff_t *pos)
1997{
1998 struct tcp_iter_state *st = seq->private;
1999 void *rc;
2000
2001 st->bucket = 0;
2002 st->offset = 0;
2003 rc = listening_get_next(seq, NULL);
2004
2005 while (rc && *pos) {
2006 rc = listening_get_next(seq, rc);
2007 --*pos;
2008 }
2009 return rc;
2010}
2011
2012static inline bool empty_bucket(const struct tcp_iter_state *st)
2013{
2014 return hlist_nulls_empty(&tcp_hashinfo.ehash[st->bucket].chain);
2015}
2016
2017/*
2018 * Get first established socket starting from bucket given in st->bucket.
2019 * If st->bucket is zero, the very first socket in the hash is returned.
2020 */
2021static void *established_get_first(struct seq_file *seq)
2022{
2023 struct tcp_iter_state *st = seq->private;
2024 struct net *net = seq_file_net(seq);
2025 void *rc = NULL;
2026
2027 st->offset = 0;
2028 for (; st->bucket <= tcp_hashinfo.ehash_mask; ++st->bucket) {
2029 struct sock *sk;
2030 struct hlist_nulls_node *node;
2031 spinlock_t *lock = inet_ehash_lockp(&tcp_hashinfo, st->bucket);
2032
2033 /* Lockless fast path for the common case of empty buckets */
2034 if (empty_bucket(st))
2035 continue;
2036
2037 spin_lock_bh(lock);
2038 sk_nulls_for_each(sk, node, &tcp_hashinfo.ehash[st->bucket].chain) {
2039 if (sk->sk_family != st->family ||
2040 !net_eq(sock_net(sk), net)) {
2041 continue;
2042 }
2043 rc = sk;
2044 goto out;
2045 }
2046 spin_unlock_bh(lock);
2047 }
2048out:
2049 return rc;
2050}
2051
2052static void *established_get_next(struct seq_file *seq, void *cur)
2053{
2054 struct sock *sk = cur;
2055 struct hlist_nulls_node *node;
2056 struct tcp_iter_state *st = seq->private;
2057 struct net *net = seq_file_net(seq);
2058
2059 ++st->num;
2060 ++st->offset;
2061
2062 sk = sk_nulls_next(sk);
2063
2064 sk_nulls_for_each_from(sk, node) {
2065 if (sk->sk_family == st->family && net_eq(sock_net(sk), net))
2066 return sk;
2067 }
2068
2069 spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
2070 ++st->bucket;
2071 return established_get_first(seq);
2072}
2073
2074static void *established_get_idx(struct seq_file *seq, loff_t pos)
2075{
2076 struct tcp_iter_state *st = seq->private;
2077 void *rc;
2078
2079 st->bucket = 0;
2080 rc = established_get_first(seq);
2081
2082 while (rc && pos) {
2083 rc = established_get_next(seq, rc);
2084 --pos;
2085 }
2086 return rc;
2087}
2088
2089static void *tcp_get_idx(struct seq_file *seq, loff_t pos)
2090{
2091 void *rc;
2092 struct tcp_iter_state *st = seq->private;
2093
2094 st->state = TCP_SEQ_STATE_LISTENING;
2095 rc = listening_get_idx(seq, &pos);
2096
2097 if (!rc) {
2098 st->state = TCP_SEQ_STATE_ESTABLISHED;
2099 rc = established_get_idx(seq, pos);
2100 }
2101
2102 return rc;
2103}
2104
2105static void *tcp_seek_last_pos(struct seq_file *seq)
2106{
2107 struct tcp_iter_state *st = seq->private;
2108 int offset = st->offset;
2109 int orig_num = st->num;
2110 void *rc = NULL;
2111
2112 switch (st->state) {
2113 case TCP_SEQ_STATE_LISTENING:
2114 if (st->bucket >= INET_LHTABLE_SIZE)
2115 break;
2116 st->state = TCP_SEQ_STATE_LISTENING;
2117 rc = listening_get_next(seq, NULL);
2118 while (offset-- && rc)
2119 rc = listening_get_next(seq, rc);
2120 if (rc)
2121 break;
2122 st->bucket = 0;
2123 st->state = TCP_SEQ_STATE_ESTABLISHED;
2124 /* Fallthrough */
2125 case TCP_SEQ_STATE_ESTABLISHED:
2126 if (st->bucket > tcp_hashinfo.ehash_mask)
2127 break;
2128 rc = established_get_first(seq);
2129 while (offset-- && rc)
2130 rc = established_get_next(seq, rc);
2131 }
2132
2133 st->num = orig_num;
2134
2135 return rc;
2136}
2137
2138static void *tcp_seq_start(struct seq_file *seq, loff_t *pos)
2139{
2140 struct tcp_iter_state *st = seq->private;
2141 void *rc;
2142
2143 if (*pos && *pos == st->last_pos) {
2144 rc = tcp_seek_last_pos(seq);
2145 if (rc)
2146 goto out;
2147 }
2148
2149 st->state = TCP_SEQ_STATE_LISTENING;
2150 st->num = 0;
2151 st->bucket = 0;
2152 st->offset = 0;
2153 rc = *pos ? tcp_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
2154
2155out:
2156 st->last_pos = *pos;
2157 return rc;
2158}
2159
2160static void *tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2161{
2162 struct tcp_iter_state *st = seq->private;
2163 void *rc = NULL;
2164
2165 if (v == SEQ_START_TOKEN) {
2166 rc = tcp_get_idx(seq, 0);
2167 goto out;
2168 }
2169
2170 switch (st->state) {
2171 case TCP_SEQ_STATE_LISTENING:
2172 rc = listening_get_next(seq, v);
2173 if (!rc) {
2174 st->state = TCP_SEQ_STATE_ESTABLISHED;
2175 st->bucket = 0;
2176 st->offset = 0;
2177 rc = established_get_first(seq);
2178 }
2179 break;
2180 case TCP_SEQ_STATE_ESTABLISHED:
2181 rc = established_get_next(seq, v);
2182 break;
2183 }
2184out:
2185 ++*pos;
2186 st->last_pos = *pos;
2187 return rc;
2188}
2189
2190static void tcp_seq_stop(struct seq_file *seq, void *v)
2191{
2192 struct tcp_iter_state *st = seq->private;
2193
2194 switch (st->state) {
2195 case TCP_SEQ_STATE_LISTENING:
2196 if (v != SEQ_START_TOKEN)
2197 spin_unlock(&tcp_hashinfo.listening_hash[st->bucket].lock);
2198 break;
2199 case TCP_SEQ_STATE_ESTABLISHED:
2200 if (v)
2201 spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
2202 break;
2203 }
2204}
2205
2206int tcp_seq_open(struct inode *inode, struct file *file)
2207{
2208 struct tcp_seq_afinfo *afinfo = PDE_DATA(inode);
2209 struct tcp_iter_state *s;
2210 int err;
2211
2212 err = seq_open_net(inode, file, &afinfo->seq_ops,
2213 sizeof(struct tcp_iter_state));
2214 if (err < 0)
2215 return err;
2216
2217 s = ((struct seq_file *)file->private_data)->private;
2218 s->family = afinfo->family;
2219 s->last_pos = 0;
2220 return 0;
2221}
2222EXPORT_SYMBOL(tcp_seq_open);
2223
2224int tcp_proc_register(struct net *net, struct tcp_seq_afinfo *afinfo)
2225{
2226 int rc = 0;
2227 struct proc_dir_entry *p;
2228
2229 afinfo->seq_ops.start = tcp_seq_start;
2230 afinfo->seq_ops.next = tcp_seq_next;
2231 afinfo->seq_ops.stop = tcp_seq_stop;
2232
2233 p = proc_create_data(afinfo->name, 0444, net->proc_net,
2234 afinfo->seq_fops, afinfo);
2235 if (!p)
2236 rc = -ENOMEM;
2237 return rc;
2238}
2239EXPORT_SYMBOL(tcp_proc_register);
2240
2241void tcp_proc_unregister(struct net *net, struct tcp_seq_afinfo *afinfo)
2242{
2243 remove_proc_entry(afinfo->name, net->proc_net);
2244}
2245EXPORT_SYMBOL(tcp_proc_unregister);
2246
2247static void get_openreq4(const struct request_sock *req,
2248 struct seq_file *f, int i)
2249{
2250 const struct inet_request_sock *ireq = inet_rsk(req);
2251 long delta = req->rsk_timer.expires - jiffies;
2252
2253 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2254 " %02X %08X:%08X %02X:%08lX %08X %5u %8d %u %d %pK",
2255 i,
2256 ireq->ir_loc_addr,
2257 ireq->ir_num,
2258 ireq->ir_rmt_addr,
2259 ntohs(ireq->ir_rmt_port),
2260 TCP_SYN_RECV,
2261 0, 0, /* could print option size, but that is af dependent. */
2262 1, /* timers active (only the expire timer) */
2263 jiffies_delta_to_clock_t(delta),
2264 req->num_timeout,
2265 from_kuid_munged(seq_user_ns(f),
2266 sock_i_uid(req->rsk_listener)),
2267 0, /* non standard timer */
2268 0, /* open_requests have no inode */
2269 0,
2270 req);
2271}
2272
2273static void get_tcp4_sock(struct sock *sk, struct seq_file *f, int i)
2274{
2275 int timer_active;
2276 unsigned long timer_expires;
2277 const struct tcp_sock *tp = tcp_sk(sk);
2278 const struct inet_connection_sock *icsk = inet_csk(sk);
2279 const struct inet_sock *inet = inet_sk(sk);
2280 const struct fastopen_queue *fastopenq = &icsk->icsk_accept_queue.fastopenq;
2281 __be32 dest = inet->inet_daddr;
2282 __be32 src = inet->inet_rcv_saddr;
2283 __u16 destp = ntohs(inet->inet_dport);
2284 __u16 srcp = ntohs(inet->inet_sport);
2285 int rx_queue;
2286 int state;
2287
2288 if (icsk->icsk_pending == ICSK_TIME_RETRANS ||
2289 icsk->icsk_pending == ICSK_TIME_REO_TIMEOUT ||
2290 icsk->icsk_pending == ICSK_TIME_LOSS_PROBE) {
2291 timer_active = 1;
2292 timer_expires = icsk->icsk_timeout;
2293 } else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
2294 timer_active = 4;
2295 timer_expires = icsk->icsk_timeout;
2296 } else if (timer_pending(&sk->sk_timer)) {
2297 timer_active = 2;
2298 timer_expires = sk->sk_timer.expires;
2299 } else {
2300 timer_active = 0;
2301 timer_expires = jiffies;
2302 }
2303
2304 state = inet_sk_state_load(sk);
2305 if (state == TCP_LISTEN)
2306 rx_queue = sk->sk_ack_backlog;
2307 else
2308 /* Because we don't lock the socket,
2309 * we might find a transient negative value.
2310 */
2311 rx_queue = max_t(int, tp->rcv_nxt - tp->copied_seq, 0);
2312
2313 seq_printf(f, "%4d: %08X:%04X %08X:%04X %02X %08X:%08X %02X:%08lX "
2314 "%08X %5u %8d %lu %d %pK %lu %lu %u %u %d",
2315 i, src, srcp, dest, destp, state,
2316 tp->write_seq - tp->snd_una,
2317 rx_queue,
2318 timer_active,
2319 jiffies_delta_to_clock_t(timer_expires - jiffies),
2320 icsk->icsk_retransmits,
2321 from_kuid_munged(seq_user_ns(f), sock_i_uid(sk)),
2322 icsk->icsk_probes_out,
2323 sock_i_ino(sk),
2324 refcount_read(&sk->sk_refcnt), sk,
2325 jiffies_to_clock_t(icsk->icsk_rto),
2326 jiffies_to_clock_t(icsk->icsk_ack.ato),
2327 (icsk->icsk_ack.quick << 1) | icsk->icsk_ack.pingpong,
2328 tp->snd_cwnd,
2329 state == TCP_LISTEN ?
2330 fastopenq->max_qlen :
2331 (tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh));
2332}
2333
2334static void get_timewait4_sock(const struct inet_timewait_sock *tw,
2335 struct seq_file *f, int i)
2336{
2337 long delta = tw->tw_timer.expires - jiffies;
2338 __be32 dest, src;
2339 __u16 destp, srcp;
2340
2341 dest = tw->tw_daddr;
2342 src = tw->tw_rcv_saddr;
2343 destp = ntohs(tw->tw_dport);
2344 srcp = ntohs(tw->tw_sport);
2345
2346 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2347 " %02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK",
2348 i, src, srcp, dest, destp, tw->tw_substate, 0, 0,
2349 3, jiffies_delta_to_clock_t(delta), 0, 0, 0, 0,
2350 refcount_read(&tw->tw_refcnt), tw);
2351}
2352
2353#define TMPSZ 150
2354
2355static int tcp4_seq_show(struct seq_file *seq, void *v)
2356{
2357 struct tcp_iter_state *st;
2358 struct sock *sk = v;
2359
2360 seq_setwidth(seq, TMPSZ - 1);
2361 if (v == SEQ_START_TOKEN) {
2362 seq_puts(seq, " sl local_address rem_address st tx_queue "
2363 "rx_queue tr tm->when retrnsmt uid timeout "
2364 "inode");
2365 goto out;
2366 }
2367 st = seq->private;
2368
2369 if (sk->sk_state == TCP_TIME_WAIT)
2370 get_timewait4_sock(v, seq, st->num);
2371 else if (sk->sk_state == TCP_NEW_SYN_RECV)
2372 get_openreq4(v, seq, st->num);
2373 else
2374 get_tcp4_sock(v, seq, st->num);
2375out:
2376 seq_pad(seq, '\n');
2377 return 0;
2378}
2379
2380static const struct file_operations tcp_afinfo_seq_fops = {
2381 .open = tcp_seq_open,
2382 .read = seq_read,
2383 .llseek = seq_lseek,
2384 .release = seq_release_net
2385};
2386
2387static struct tcp_seq_afinfo tcp4_seq_afinfo = {
2388 .name = "tcp",
2389 .family = AF_INET,
2390 .seq_fops = &tcp_afinfo_seq_fops,
2391 .seq_ops = {
2392 .show = tcp4_seq_show,
2393 },
2394};
2395
2396static int __net_init tcp4_proc_init_net(struct net *net)
2397{
2398 return tcp_proc_register(net, &tcp4_seq_afinfo);
2399}
2400
2401static void __net_exit tcp4_proc_exit_net(struct net *net)
2402{
2403 tcp_proc_unregister(net, &tcp4_seq_afinfo);
2404}
2405
2406static struct pernet_operations tcp4_net_ops = {
2407 .init = tcp4_proc_init_net,
2408 .exit = tcp4_proc_exit_net,
2409};
2410
2411int __init tcp4_proc_init(void)
2412{
2413 return register_pernet_subsys(&tcp4_net_ops);
2414}
2415
2416void tcp4_proc_exit(void)
2417{
2418 unregister_pernet_subsys(&tcp4_net_ops);
2419}
2420#endif /* CONFIG_PROC_FS */
2421
2422struct proto tcp_prot = {
2423 .name = "TCP",
2424 .owner = THIS_MODULE,
2425 .close = tcp_close,
2426 .pre_connect = tcp_v4_pre_connect,
2427 .connect = tcp_v4_connect,
2428 .disconnect = tcp_disconnect,
2429 .accept = inet_csk_accept,
2430 .ioctl = tcp_ioctl,
2431 .init = tcp_v4_init_sock,
2432 .destroy = tcp_v4_destroy_sock,
2433 .shutdown = tcp_shutdown,
2434 .setsockopt = tcp_setsockopt,
2435 .getsockopt = tcp_getsockopt,
2436 .keepalive = tcp_set_keepalive,
2437 .recvmsg = tcp_recvmsg,
2438 .sendmsg = tcp_sendmsg,
2439 .sendpage = tcp_sendpage,
2440 .backlog_rcv = tcp_v4_do_rcv,
2441 .release_cb = tcp_release_cb,
2442 .hash = inet_hash,
2443 .unhash = inet_unhash,
2444 .get_port = inet_csk_get_port,
2445 .enter_memory_pressure = tcp_enter_memory_pressure,
2446 .leave_memory_pressure = tcp_leave_memory_pressure,
2447 .stream_memory_free = tcp_stream_memory_free,
2448 .sockets_allocated = &tcp_sockets_allocated,
2449 .orphan_count = &tcp_orphan_count,
2450 .memory_allocated = &tcp_memory_allocated,
2451 .memory_pressure = &tcp_memory_pressure,
2452 .sysctl_mem = sysctl_tcp_mem,
2453 .sysctl_wmem_offset = offsetof(struct net, ipv4.sysctl_tcp_wmem),
2454 .sysctl_rmem_offset = offsetof(struct net, ipv4.sysctl_tcp_rmem),
2455 .max_header = MAX_TCP_HEADER,
2456 .obj_size = sizeof(struct tcp_sock),
2457 .slab_flags = SLAB_TYPESAFE_BY_RCU,
2458 .twsk_prot = &tcp_timewait_sock_ops,
2459 .rsk_prot = &tcp_request_sock_ops,
2460 .h.hashinfo = &tcp_hashinfo,
2461 .no_autobind = true,
2462#ifdef CONFIG_COMPAT
2463 .compat_setsockopt = compat_tcp_setsockopt,
2464 .compat_getsockopt = compat_tcp_getsockopt,
2465#endif
2466 .diag_destroy = tcp_abort,
2467};
2468EXPORT_SYMBOL(tcp_prot);
2469
2470static void __net_exit tcp_sk_exit(struct net *net)
2471{
2472 int cpu;
2473
2474 module_put(net->ipv4.tcp_congestion_control->owner);
2475
2476 for_each_possible_cpu(cpu)
2477 inet_ctl_sock_destroy(*per_cpu_ptr(net->ipv4.tcp_sk, cpu));
2478 free_percpu(net->ipv4.tcp_sk);
2479}
2480
2481static int __net_init tcp_sk_init(struct net *net)
2482{
2483 int res, cpu, cnt;
2484
2485 net->ipv4.tcp_sk = alloc_percpu(struct sock *);
2486 if (!net->ipv4.tcp_sk)
2487 return -ENOMEM;
2488
2489 for_each_possible_cpu(cpu) {
2490 struct sock *sk;
2491
2492 res = inet_ctl_sock_create(&sk, PF_INET, SOCK_RAW,
2493 IPPROTO_TCP, net);
2494 if (res)
2495 goto fail;
2496 sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
2497 *per_cpu_ptr(net->ipv4.tcp_sk, cpu) = sk;
2498 }
2499
2500 net->ipv4.sysctl_tcp_ecn = 2;
2501 net->ipv4.sysctl_tcp_ecn_fallback = 1;
2502
2503 net->ipv4.sysctl_tcp_base_mss = TCP_BASE_MSS;
2504 net->ipv4.sysctl_tcp_probe_threshold = TCP_PROBE_THRESHOLD;
2505 net->ipv4.sysctl_tcp_probe_interval = TCP_PROBE_INTERVAL;
2506
2507 net->ipv4.sysctl_tcp_keepalive_time = TCP_KEEPALIVE_TIME;
2508 net->ipv4.sysctl_tcp_keepalive_probes = TCP_KEEPALIVE_PROBES;
2509 net->ipv4.sysctl_tcp_keepalive_intvl = TCP_KEEPALIVE_INTVL;
2510
2511 net->ipv4.sysctl_tcp_syn_retries = TCP_SYN_RETRIES;
2512 net->ipv4.sysctl_tcp_synack_retries = TCP_SYNACK_RETRIES;
2513 net->ipv4.sysctl_tcp_syncookies = 1;
2514 net->ipv4.sysctl_tcp_reordering = TCP_FASTRETRANS_THRESH;
2515 net->ipv4.sysctl_tcp_retries1 = TCP_RETR1;
2516 net->ipv4.sysctl_tcp_retries2 = TCP_RETR2;
2517 net->ipv4.sysctl_tcp_orphan_retries = 0;
2518 net->ipv4.sysctl_tcp_fin_timeout = TCP_FIN_TIMEOUT;
2519 net->ipv4.sysctl_tcp_notsent_lowat = UINT_MAX;
2520 net->ipv4.sysctl_tcp_tw_reuse = 0;
2521
2522 cnt = tcp_hashinfo.ehash_mask + 1;
2523 net->ipv4.tcp_death_row.sysctl_max_tw_buckets = (cnt + 1) / 2;
2524 net->ipv4.tcp_death_row.hashinfo = &tcp_hashinfo;
2525
2526 net->ipv4.sysctl_max_syn_backlog = max(128, cnt / 256);
2527 net->ipv4.sysctl_tcp_sack = 1;
2528 net->ipv4.sysctl_tcp_window_scaling = 1;
2529 net->ipv4.sysctl_tcp_timestamps = 1;
2530 net->ipv4.sysctl_tcp_early_retrans = 3;
2531 net->ipv4.sysctl_tcp_recovery = TCP_RACK_LOSS_DETECTION;
2532 net->ipv4.sysctl_tcp_slow_start_after_idle = 1; /* By default, RFC2861 behavior. */
2533 net->ipv4.sysctl_tcp_retrans_collapse = 1;
2534 net->ipv4.sysctl_tcp_max_reordering = 300;
2535 net->ipv4.sysctl_tcp_dsack = 1;
2536 net->ipv4.sysctl_tcp_app_win = 31;
2537 net->ipv4.sysctl_tcp_adv_win_scale = 1;
2538 net->ipv4.sysctl_tcp_frto = 2;
2539 net->ipv4.sysctl_tcp_moderate_rcvbuf = 1;
2540 /* This limits the percentage of the congestion window which we
2541 * will allow a single TSO frame to consume. Building TSO frames
2542 * which are too large can cause TCP streams to be bursty.
2543 */
2544 net->ipv4.sysctl_tcp_tso_win_divisor = 3;
2545 /* Default TSQ limit of four TSO segments */
2546 net->ipv4.sysctl_tcp_limit_output_bytes = 262144;
2547 /* rfc5961 challenge ack rate limiting */
2548 net->ipv4.sysctl_tcp_challenge_ack_limit = 1000;
2549 net->ipv4.sysctl_tcp_min_tso_segs = 2;
2550 net->ipv4.sysctl_tcp_min_rtt_wlen = 300;
2551 net->ipv4.sysctl_tcp_autocorking = 1;
2552 net->ipv4.sysctl_tcp_invalid_ratelimit = HZ/2;
2553 net->ipv4.sysctl_tcp_pacing_ss_ratio = 200;
2554 net->ipv4.sysctl_tcp_pacing_ca_ratio = 120;
2555 if (net != &init_net) {
2556 memcpy(net->ipv4.sysctl_tcp_rmem,
2557 init_net.ipv4.sysctl_tcp_rmem,
2558 sizeof(init_net.ipv4.sysctl_tcp_rmem));
2559 memcpy(net->ipv4.sysctl_tcp_wmem,
2560 init_net.ipv4.sysctl_tcp_wmem,
2561 sizeof(init_net.ipv4.sysctl_tcp_wmem));
2562 }
2563 net->ipv4.sysctl_tcp_fastopen = TFO_CLIENT_ENABLE;
2564 spin_lock_init(&net->ipv4.tcp_fastopen_ctx_lock);
2565 net->ipv4.sysctl_tcp_fastopen_blackhole_timeout = 60 * 60;
2566 atomic_set(&net->ipv4.tfo_active_disable_times, 0);
2567
2568 /* Reno is always built in */
2569 if (!net_eq(net, &init_net) &&
2570 try_module_get(init_net.ipv4.tcp_congestion_control->owner))
2571 net->ipv4.tcp_congestion_control = init_net.ipv4.tcp_congestion_control;
2572 else
2573 net->ipv4.tcp_congestion_control = &tcp_reno;
2574
2575 return 0;
2576fail:
2577 tcp_sk_exit(net);
2578
2579 return res;
2580}
2581
2582static void __net_exit tcp_sk_exit_batch(struct list_head *net_exit_list)
2583{
2584 struct net *net;
2585
2586 inet_twsk_purge(&tcp_hashinfo, AF_INET);
2587
2588 list_for_each_entry(net, net_exit_list, exit_list)
2589 tcp_fastopen_ctx_destroy(net);
2590}
2591
2592static struct pernet_operations __net_initdata tcp_sk_ops = {
2593 .init = tcp_sk_init,
2594 .exit = tcp_sk_exit,
2595 .exit_batch = tcp_sk_exit_batch,
2596};
2597
2598void __init tcp_v4_init(void)
2599{
2600 if (register_pernet_subsys(&tcp_sk_ops))
2601 panic("Failed to create the TCP control socket.\n");
2602}