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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 DEFINE_PER_CPU(struct sock *, ipv4_tcp_sk);
95
96static u32 tcp_v4_init_seq(const struct sk_buff *skb)
97{
98 return secure_tcp_seq(ip_hdr(skb)->daddr,
99 ip_hdr(skb)->saddr,
100 tcp_hdr(skb)->dest,
101 tcp_hdr(skb)->source);
102}
103
104static u32 tcp_v4_init_ts_off(const struct net *net, const struct sk_buff *skb)
105{
106 return secure_tcp_ts_off(net, ip_hdr(skb)->daddr, ip_hdr(skb)->saddr);
107}
108
109int tcp_twsk_unique(struct sock *sk, struct sock *sktw, void *twp)
110{
111 int reuse = READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_tw_reuse);
112 const struct inet_timewait_sock *tw = inet_twsk(sktw);
113 const struct tcp_timewait_sock *tcptw = tcp_twsk(sktw);
114 struct tcp_sock *tp = tcp_sk(sk);
115
116 if (reuse == 2) {
117 /* Still does not detect *everything* that goes through
118 * lo, since we require a loopback src or dst address
119 * or direct binding to 'lo' interface.
120 */
121 bool loopback = false;
122 if (tw->tw_bound_dev_if == LOOPBACK_IFINDEX)
123 loopback = true;
124#if IS_ENABLED(CONFIG_IPV6)
125 if (tw->tw_family == AF_INET6) {
126 if (ipv6_addr_loopback(&tw->tw_v6_daddr) ||
127 ipv6_addr_v4mapped_loopback(&tw->tw_v6_daddr) ||
128 ipv6_addr_loopback(&tw->tw_v6_rcv_saddr) ||
129 ipv6_addr_v4mapped_loopback(&tw->tw_v6_rcv_saddr))
130 loopback = true;
131 } else
132#endif
133 {
134 if (ipv4_is_loopback(tw->tw_daddr) ||
135 ipv4_is_loopback(tw->tw_rcv_saddr))
136 loopback = true;
137 }
138 if (!loopback)
139 reuse = 0;
140 }
141
142 /* With PAWS, it is safe from the viewpoint
143 of data integrity. Even without PAWS it is safe provided sequence
144 spaces do not overlap i.e. at data rates <= 80Mbit/sec.
145
146 Actually, the idea is close to VJ's one, only timestamp cache is
147 held not per host, but per port pair and TW bucket is used as state
148 holder.
149
150 If TW bucket has been already destroyed we fall back to VJ's scheme
151 and use initial timestamp retrieved from peer table.
152 */
153 if (tcptw->tw_ts_recent_stamp &&
154 (!twp || (reuse && time_after32(ktime_get_seconds(),
155 tcptw->tw_ts_recent_stamp)))) {
156 /* In case of repair and re-using TIME-WAIT sockets we still
157 * want to be sure that it is safe as above but honor the
158 * sequence numbers and time stamps set as part of the repair
159 * process.
160 *
161 * Without this check re-using a TIME-WAIT socket with TCP
162 * repair would accumulate a -1 on the repair assigned
163 * sequence number. The first time it is reused the sequence
164 * is -1, the second time -2, etc. This fixes that issue
165 * without appearing to create any others.
166 */
167 if (likely(!tp->repair)) {
168 u32 seq = tcptw->tw_snd_nxt + 65535 + 2;
169
170 if (!seq)
171 seq = 1;
172 WRITE_ONCE(tp->write_seq, seq);
173 tp->rx_opt.ts_recent = tcptw->tw_ts_recent;
174 tp->rx_opt.ts_recent_stamp = tcptw->tw_ts_recent_stamp;
175 }
176 sock_hold(sktw);
177 return 1;
178 }
179
180 return 0;
181}
182EXPORT_SYMBOL_GPL(tcp_twsk_unique);
183
184static int tcp_v4_pre_connect(struct sock *sk, struct sockaddr *uaddr,
185 int addr_len)
186{
187 /* This check is replicated from tcp_v4_connect() and intended to
188 * prevent BPF program called below from accessing bytes that are out
189 * of the bound specified by user in addr_len.
190 */
191 if (addr_len < sizeof(struct sockaddr_in))
192 return -EINVAL;
193
194 sock_owned_by_me(sk);
195
196 return BPF_CGROUP_RUN_PROG_INET4_CONNECT(sk, uaddr);
197}
198
199/* This will initiate an outgoing connection. */
200int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
201{
202 struct sockaddr_in *usin = (struct sockaddr_in *)uaddr;
203 struct inet_timewait_death_row *tcp_death_row;
204 struct inet_sock *inet = inet_sk(sk);
205 struct tcp_sock *tp = tcp_sk(sk);
206 struct ip_options_rcu *inet_opt;
207 struct net *net = sock_net(sk);
208 __be16 orig_sport, orig_dport;
209 __be32 daddr, nexthop;
210 struct flowi4 *fl4;
211 struct rtable *rt;
212 int err;
213
214 if (addr_len < sizeof(struct sockaddr_in))
215 return -EINVAL;
216
217 if (usin->sin_family != AF_INET)
218 return -EAFNOSUPPORT;
219
220 nexthop = daddr = usin->sin_addr.s_addr;
221 inet_opt = rcu_dereference_protected(inet->inet_opt,
222 lockdep_sock_is_held(sk));
223 if (inet_opt && inet_opt->opt.srr) {
224 if (!daddr)
225 return -EINVAL;
226 nexthop = inet_opt->opt.faddr;
227 }
228
229 orig_sport = inet->inet_sport;
230 orig_dport = usin->sin_port;
231 fl4 = &inet->cork.fl.u.ip4;
232 rt = ip_route_connect(fl4, nexthop, inet->inet_saddr,
233 sk->sk_bound_dev_if, IPPROTO_TCP, orig_sport,
234 orig_dport, sk);
235 if (IS_ERR(rt)) {
236 err = PTR_ERR(rt);
237 if (err == -ENETUNREACH)
238 IP_INC_STATS(net, IPSTATS_MIB_OUTNOROUTES);
239 return err;
240 }
241
242 if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) {
243 ip_rt_put(rt);
244 return -ENETUNREACH;
245 }
246
247 if (!inet_opt || !inet_opt->opt.srr)
248 daddr = fl4->daddr;
249
250 tcp_death_row = &sock_net(sk)->ipv4.tcp_death_row;
251
252 if (!inet->inet_saddr) {
253 err = inet_bhash2_update_saddr(sk, &fl4->saddr, AF_INET);
254 if (err) {
255 ip_rt_put(rt);
256 return err;
257 }
258 } else {
259 sk_rcv_saddr_set(sk, inet->inet_saddr);
260 }
261
262 if (tp->rx_opt.ts_recent_stamp && inet->inet_daddr != daddr) {
263 /* Reset inherited state */
264 tp->rx_opt.ts_recent = 0;
265 tp->rx_opt.ts_recent_stamp = 0;
266 if (likely(!tp->repair))
267 WRITE_ONCE(tp->write_seq, 0);
268 }
269
270 inet->inet_dport = usin->sin_port;
271 sk_daddr_set(sk, daddr);
272
273 inet_csk(sk)->icsk_ext_hdr_len = 0;
274 if (inet_opt)
275 inet_csk(sk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
276
277 tp->rx_opt.mss_clamp = TCP_MSS_DEFAULT;
278
279 /* Socket identity is still unknown (sport may be zero).
280 * However we set state to SYN-SENT and not releasing socket
281 * lock select source port, enter ourselves into the hash tables and
282 * complete initialization after this.
283 */
284 tcp_set_state(sk, TCP_SYN_SENT);
285 err = inet_hash_connect(tcp_death_row, sk);
286 if (err)
287 goto failure;
288
289 sk_set_txhash(sk);
290
291 rt = ip_route_newports(fl4, rt, orig_sport, orig_dport,
292 inet->inet_sport, inet->inet_dport, sk);
293 if (IS_ERR(rt)) {
294 err = PTR_ERR(rt);
295 rt = NULL;
296 goto failure;
297 }
298 /* OK, now commit destination to socket. */
299 sk->sk_gso_type = SKB_GSO_TCPV4;
300 sk_setup_caps(sk, &rt->dst);
301 rt = NULL;
302
303 if (likely(!tp->repair)) {
304 if (!tp->write_seq)
305 WRITE_ONCE(tp->write_seq,
306 secure_tcp_seq(inet->inet_saddr,
307 inet->inet_daddr,
308 inet->inet_sport,
309 usin->sin_port));
310 tp->tsoffset = secure_tcp_ts_off(net, inet->inet_saddr,
311 inet->inet_daddr);
312 }
313
314 inet->inet_id = get_random_u16();
315
316 if (tcp_fastopen_defer_connect(sk, &err))
317 return err;
318 if (err)
319 goto failure;
320
321 err = tcp_connect(sk);
322
323 if (err)
324 goto failure;
325
326 return 0;
327
328failure:
329 /*
330 * This unhashes the socket and releases the local port,
331 * if necessary.
332 */
333 tcp_set_state(sk, TCP_CLOSE);
334 inet_bhash2_reset_saddr(sk);
335 ip_rt_put(rt);
336 sk->sk_route_caps = 0;
337 inet->inet_dport = 0;
338 return err;
339}
340EXPORT_SYMBOL(tcp_v4_connect);
341
342/*
343 * This routine reacts to ICMP_FRAG_NEEDED mtu indications as defined in RFC1191.
344 * It can be called through tcp_release_cb() if socket was owned by user
345 * at the time tcp_v4_err() was called to handle ICMP message.
346 */
347void tcp_v4_mtu_reduced(struct sock *sk)
348{
349 struct inet_sock *inet = inet_sk(sk);
350 struct dst_entry *dst;
351 u32 mtu;
352
353 if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE))
354 return;
355 mtu = READ_ONCE(tcp_sk(sk)->mtu_info);
356 dst = inet_csk_update_pmtu(sk, mtu);
357 if (!dst)
358 return;
359
360 /* Something is about to be wrong... Remember soft error
361 * for the case, if this connection will not able to recover.
362 */
363 if (mtu < dst_mtu(dst) && ip_dont_fragment(sk, dst))
364 sk->sk_err_soft = EMSGSIZE;
365
366 mtu = dst_mtu(dst);
367
368 if (inet->pmtudisc != IP_PMTUDISC_DONT &&
369 ip_sk_accept_pmtu(sk) &&
370 inet_csk(sk)->icsk_pmtu_cookie > mtu) {
371 tcp_sync_mss(sk, mtu);
372
373 /* Resend the TCP packet because it's
374 * clear that the old packet has been
375 * dropped. This is the new "fast" path mtu
376 * discovery.
377 */
378 tcp_simple_retransmit(sk);
379 } /* else let the usual retransmit timer handle it */
380}
381EXPORT_SYMBOL(tcp_v4_mtu_reduced);
382
383static void do_redirect(struct sk_buff *skb, struct sock *sk)
384{
385 struct dst_entry *dst = __sk_dst_check(sk, 0);
386
387 if (dst)
388 dst->ops->redirect(dst, sk, skb);
389}
390
391
392/* handle ICMP messages on TCP_NEW_SYN_RECV request sockets */
393void tcp_req_err(struct sock *sk, u32 seq, bool abort)
394{
395 struct request_sock *req = inet_reqsk(sk);
396 struct net *net = sock_net(sk);
397
398 /* ICMPs are not backlogged, hence we cannot get
399 * an established socket here.
400 */
401 if (seq != tcp_rsk(req)->snt_isn) {
402 __NET_INC_STATS(net, LINUX_MIB_OUTOFWINDOWICMPS);
403 } else if (abort) {
404 /*
405 * Still in SYN_RECV, just remove it silently.
406 * There is no good way to pass the error to the newly
407 * created socket, and POSIX does not want network
408 * errors returned from accept().
409 */
410 inet_csk_reqsk_queue_drop(req->rsk_listener, req);
411 tcp_listendrop(req->rsk_listener);
412 }
413 reqsk_put(req);
414}
415EXPORT_SYMBOL(tcp_req_err);
416
417/* TCP-LD (RFC 6069) logic */
418void tcp_ld_RTO_revert(struct sock *sk, u32 seq)
419{
420 struct inet_connection_sock *icsk = inet_csk(sk);
421 struct tcp_sock *tp = tcp_sk(sk);
422 struct sk_buff *skb;
423 s32 remaining;
424 u32 delta_us;
425
426 if (sock_owned_by_user(sk))
427 return;
428
429 if (seq != tp->snd_una || !icsk->icsk_retransmits ||
430 !icsk->icsk_backoff)
431 return;
432
433 skb = tcp_rtx_queue_head(sk);
434 if (WARN_ON_ONCE(!skb))
435 return;
436
437 icsk->icsk_backoff--;
438 icsk->icsk_rto = tp->srtt_us ? __tcp_set_rto(tp) : TCP_TIMEOUT_INIT;
439 icsk->icsk_rto = inet_csk_rto_backoff(icsk, TCP_RTO_MAX);
440
441 tcp_mstamp_refresh(tp);
442 delta_us = (u32)(tp->tcp_mstamp - tcp_skb_timestamp_us(skb));
443 remaining = icsk->icsk_rto - usecs_to_jiffies(delta_us);
444
445 if (remaining > 0) {
446 inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
447 remaining, TCP_RTO_MAX);
448 } else {
449 /* RTO revert clocked out retransmission.
450 * Will retransmit now.
451 */
452 tcp_retransmit_timer(sk);
453 }
454}
455EXPORT_SYMBOL(tcp_ld_RTO_revert);
456
457/*
458 * This routine is called by the ICMP module when it gets some
459 * sort of error condition. If err < 0 then the socket should
460 * be closed and the error returned to the user. If err > 0
461 * it's just the icmp type << 8 | icmp code. After adjustment
462 * header points to the first 8 bytes of the tcp header. We need
463 * to find the appropriate port.
464 *
465 * The locking strategy used here is very "optimistic". When
466 * someone else accesses the socket the ICMP is just dropped
467 * and for some paths there is no check at all.
468 * A more general error queue to queue errors for later handling
469 * is probably better.
470 *
471 */
472
473int tcp_v4_err(struct sk_buff *skb, u32 info)
474{
475 const struct iphdr *iph = (const struct iphdr *)skb->data;
476 struct tcphdr *th = (struct tcphdr *)(skb->data + (iph->ihl << 2));
477 struct tcp_sock *tp;
478 struct inet_sock *inet;
479 const int type = icmp_hdr(skb)->type;
480 const int code = icmp_hdr(skb)->code;
481 struct sock *sk;
482 struct request_sock *fastopen;
483 u32 seq, snd_una;
484 int err;
485 struct net *net = dev_net(skb->dev);
486
487 sk = __inet_lookup_established(net, net->ipv4.tcp_death_row.hashinfo,
488 iph->daddr, th->dest, iph->saddr,
489 ntohs(th->source), inet_iif(skb), 0);
490 if (!sk) {
491 __ICMP_INC_STATS(net, ICMP_MIB_INERRORS);
492 return -ENOENT;
493 }
494 if (sk->sk_state == TCP_TIME_WAIT) {
495 inet_twsk_put(inet_twsk(sk));
496 return 0;
497 }
498 seq = ntohl(th->seq);
499 if (sk->sk_state == TCP_NEW_SYN_RECV) {
500 tcp_req_err(sk, seq, type == ICMP_PARAMETERPROB ||
501 type == ICMP_TIME_EXCEEDED ||
502 (type == ICMP_DEST_UNREACH &&
503 (code == ICMP_NET_UNREACH ||
504 code == ICMP_HOST_UNREACH)));
505 return 0;
506 }
507
508 bh_lock_sock(sk);
509 /* If too many ICMPs get dropped on busy
510 * servers this needs to be solved differently.
511 * We do take care of PMTU discovery (RFC1191) special case :
512 * we can receive locally generated ICMP messages while socket is held.
513 */
514 if (sock_owned_by_user(sk)) {
515 if (!(type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED))
516 __NET_INC_STATS(net, LINUX_MIB_LOCKDROPPEDICMPS);
517 }
518 if (sk->sk_state == TCP_CLOSE)
519 goto out;
520
521 if (static_branch_unlikely(&ip4_min_ttl)) {
522 /* min_ttl can be changed concurrently from do_ip_setsockopt() */
523 if (unlikely(iph->ttl < READ_ONCE(inet_sk(sk)->min_ttl))) {
524 __NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP);
525 goto out;
526 }
527 }
528
529 tp = tcp_sk(sk);
530 /* XXX (TFO) - tp->snd_una should be ISN (tcp_create_openreq_child() */
531 fastopen = rcu_dereference(tp->fastopen_rsk);
532 snd_una = fastopen ? tcp_rsk(fastopen)->snt_isn : tp->snd_una;
533 if (sk->sk_state != TCP_LISTEN &&
534 !between(seq, snd_una, tp->snd_nxt)) {
535 __NET_INC_STATS(net, LINUX_MIB_OUTOFWINDOWICMPS);
536 goto out;
537 }
538
539 switch (type) {
540 case ICMP_REDIRECT:
541 if (!sock_owned_by_user(sk))
542 do_redirect(skb, sk);
543 goto out;
544 case ICMP_SOURCE_QUENCH:
545 /* Just silently ignore these. */
546 goto out;
547 case ICMP_PARAMETERPROB:
548 err = EPROTO;
549 break;
550 case ICMP_DEST_UNREACH:
551 if (code > NR_ICMP_UNREACH)
552 goto out;
553
554 if (code == ICMP_FRAG_NEEDED) { /* PMTU discovery (RFC1191) */
555 /* We are not interested in TCP_LISTEN and open_requests
556 * (SYN-ACKs send out by Linux are always <576bytes so
557 * they should go through unfragmented).
558 */
559 if (sk->sk_state == TCP_LISTEN)
560 goto out;
561
562 WRITE_ONCE(tp->mtu_info, info);
563 if (!sock_owned_by_user(sk)) {
564 tcp_v4_mtu_reduced(sk);
565 } else {
566 if (!test_and_set_bit(TCP_MTU_REDUCED_DEFERRED, &sk->sk_tsq_flags))
567 sock_hold(sk);
568 }
569 goto out;
570 }
571
572 err = icmp_err_convert[code].errno;
573 /* check if this ICMP message allows revert of backoff.
574 * (see RFC 6069)
575 */
576 if (!fastopen &&
577 (code == ICMP_NET_UNREACH || code == ICMP_HOST_UNREACH))
578 tcp_ld_RTO_revert(sk, seq);
579 break;
580 case ICMP_TIME_EXCEEDED:
581 err = EHOSTUNREACH;
582 break;
583 default:
584 goto out;
585 }
586
587 switch (sk->sk_state) {
588 case TCP_SYN_SENT:
589 case TCP_SYN_RECV:
590 /* Only in fast or simultaneous open. If a fast open socket is
591 * already accepted it is treated as a connected one below.
592 */
593 if (fastopen && !fastopen->sk)
594 break;
595
596 ip_icmp_error(sk, skb, err, th->dest, info, (u8 *)th);
597
598 if (!sock_owned_by_user(sk)) {
599 sk->sk_err = err;
600
601 sk_error_report(sk);
602
603 tcp_done(sk);
604 } else {
605 sk->sk_err_soft = err;
606 }
607 goto out;
608 }
609
610 /* If we've already connected we will keep trying
611 * until we time out, or the user gives up.
612 *
613 * rfc1122 4.2.3.9 allows to consider as hard errors
614 * only PROTO_UNREACH and PORT_UNREACH (well, FRAG_FAILED too,
615 * but it is obsoleted by pmtu discovery).
616 *
617 * Note, that in modern internet, where routing is unreliable
618 * and in each dark corner broken firewalls sit, sending random
619 * errors ordered by their masters even this two messages finally lose
620 * their original sense (even Linux sends invalid PORT_UNREACHs)
621 *
622 * Now we are in compliance with RFCs.
623 * --ANK (980905)
624 */
625
626 inet = inet_sk(sk);
627 if (!sock_owned_by_user(sk) && inet->recverr) {
628 sk->sk_err = err;
629 sk_error_report(sk);
630 } else { /* Only an error on timeout */
631 sk->sk_err_soft = err;
632 }
633
634out:
635 bh_unlock_sock(sk);
636 sock_put(sk);
637 return 0;
638}
639
640void __tcp_v4_send_check(struct sk_buff *skb, __be32 saddr, __be32 daddr)
641{
642 struct tcphdr *th = tcp_hdr(skb);
643
644 th->check = ~tcp_v4_check(skb->len, saddr, daddr, 0);
645 skb->csum_start = skb_transport_header(skb) - skb->head;
646 skb->csum_offset = offsetof(struct tcphdr, check);
647}
648
649/* This routine computes an IPv4 TCP checksum. */
650void tcp_v4_send_check(struct sock *sk, struct sk_buff *skb)
651{
652 const struct inet_sock *inet = inet_sk(sk);
653
654 __tcp_v4_send_check(skb, inet->inet_saddr, inet->inet_daddr);
655}
656EXPORT_SYMBOL(tcp_v4_send_check);
657
658/*
659 * This routine will send an RST to the other tcp.
660 *
661 * Someone asks: why I NEVER use socket parameters (TOS, TTL etc.)
662 * for reset.
663 * Answer: if a packet caused RST, it is not for a socket
664 * existing in our system, if it is matched to a socket,
665 * it is just duplicate segment or bug in other side's TCP.
666 * So that we build reply only basing on parameters
667 * arrived with segment.
668 * Exception: precedence violation. We do not implement it in any case.
669 */
670
671#ifdef CONFIG_TCP_MD5SIG
672#define OPTION_BYTES TCPOLEN_MD5SIG_ALIGNED
673#else
674#define OPTION_BYTES sizeof(__be32)
675#endif
676
677static void tcp_v4_send_reset(const struct sock *sk, struct sk_buff *skb)
678{
679 const struct tcphdr *th = tcp_hdr(skb);
680 struct {
681 struct tcphdr th;
682 __be32 opt[OPTION_BYTES / sizeof(__be32)];
683 } rep;
684 struct ip_reply_arg arg;
685#ifdef CONFIG_TCP_MD5SIG
686 struct tcp_md5sig_key *key = NULL;
687 const __u8 *hash_location = NULL;
688 unsigned char newhash[16];
689 int genhash;
690 struct sock *sk1 = NULL;
691#endif
692 u64 transmit_time = 0;
693 struct sock *ctl_sk;
694 struct net *net;
695
696 /* Never send a reset in response to a reset. */
697 if (th->rst)
698 return;
699
700 /* If sk not NULL, it means we did a successful lookup and incoming
701 * route had to be correct. prequeue might have dropped our dst.
702 */
703 if (!sk && skb_rtable(skb)->rt_type != RTN_LOCAL)
704 return;
705
706 /* Swap the send and the receive. */
707 memset(&rep, 0, sizeof(rep));
708 rep.th.dest = th->source;
709 rep.th.source = th->dest;
710 rep.th.doff = sizeof(struct tcphdr) / 4;
711 rep.th.rst = 1;
712
713 if (th->ack) {
714 rep.th.seq = th->ack_seq;
715 } else {
716 rep.th.ack = 1;
717 rep.th.ack_seq = htonl(ntohl(th->seq) + th->syn + th->fin +
718 skb->len - (th->doff << 2));
719 }
720
721 memset(&arg, 0, sizeof(arg));
722 arg.iov[0].iov_base = (unsigned char *)&rep;
723 arg.iov[0].iov_len = sizeof(rep.th);
724
725 net = sk ? sock_net(sk) : dev_net(skb_dst(skb)->dev);
726#ifdef CONFIG_TCP_MD5SIG
727 rcu_read_lock();
728 hash_location = tcp_parse_md5sig_option(th);
729 if (sk && sk_fullsock(sk)) {
730 const union tcp_md5_addr *addr;
731 int l3index;
732
733 /* sdif set, means packet ingressed via a device
734 * in an L3 domain and inet_iif is set to it.
735 */
736 l3index = tcp_v4_sdif(skb) ? inet_iif(skb) : 0;
737 addr = (union tcp_md5_addr *)&ip_hdr(skb)->saddr;
738 key = tcp_md5_do_lookup(sk, l3index, addr, AF_INET);
739 } else if (hash_location) {
740 const union tcp_md5_addr *addr;
741 int sdif = tcp_v4_sdif(skb);
742 int dif = inet_iif(skb);
743 int l3index;
744
745 /*
746 * active side is lost. Try to find listening socket through
747 * source port, and then find md5 key through listening socket.
748 * we are not loose security here:
749 * Incoming packet is checked with md5 hash with finding key,
750 * no RST generated if md5 hash doesn't match.
751 */
752 sk1 = __inet_lookup_listener(net, net->ipv4.tcp_death_row.hashinfo,
753 NULL, 0, ip_hdr(skb)->saddr,
754 th->source, ip_hdr(skb)->daddr,
755 ntohs(th->source), dif, sdif);
756 /* don't send rst if it can't find key */
757 if (!sk1)
758 goto out;
759
760 /* sdif set, means packet ingressed via a device
761 * in an L3 domain and dif is set to it.
762 */
763 l3index = sdif ? dif : 0;
764 addr = (union tcp_md5_addr *)&ip_hdr(skb)->saddr;
765 key = tcp_md5_do_lookup(sk1, l3index, addr, AF_INET);
766 if (!key)
767 goto out;
768
769
770 genhash = tcp_v4_md5_hash_skb(newhash, key, NULL, skb);
771 if (genhash || memcmp(hash_location, newhash, 16) != 0)
772 goto out;
773
774 }
775
776 if (key) {
777 rep.opt[0] = htonl((TCPOPT_NOP << 24) |
778 (TCPOPT_NOP << 16) |
779 (TCPOPT_MD5SIG << 8) |
780 TCPOLEN_MD5SIG);
781 /* Update length and the length the header thinks exists */
782 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED;
783 rep.th.doff = arg.iov[0].iov_len / 4;
784
785 tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[1],
786 key, ip_hdr(skb)->saddr,
787 ip_hdr(skb)->daddr, &rep.th);
788 }
789#endif
790 /* Can't co-exist with TCPMD5, hence check rep.opt[0] */
791 if (rep.opt[0] == 0) {
792 __be32 mrst = mptcp_reset_option(skb);
793
794 if (mrst) {
795 rep.opt[0] = mrst;
796 arg.iov[0].iov_len += sizeof(mrst);
797 rep.th.doff = arg.iov[0].iov_len / 4;
798 }
799 }
800
801 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
802 ip_hdr(skb)->saddr, /* XXX */
803 arg.iov[0].iov_len, IPPROTO_TCP, 0);
804 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
805 arg.flags = (sk && inet_sk_transparent(sk)) ? IP_REPLY_ARG_NOSRCCHECK : 0;
806
807 /* When socket is gone, all binding information is lost.
808 * routing might fail in this case. No choice here, if we choose to force
809 * input interface, we will misroute in case of asymmetric route.
810 */
811 if (sk) {
812 arg.bound_dev_if = sk->sk_bound_dev_if;
813 if (sk_fullsock(sk))
814 trace_tcp_send_reset(sk, skb);
815 }
816
817 BUILD_BUG_ON(offsetof(struct sock, sk_bound_dev_if) !=
818 offsetof(struct inet_timewait_sock, tw_bound_dev_if));
819
820 arg.tos = ip_hdr(skb)->tos;
821 arg.uid = sock_net_uid(net, sk && sk_fullsock(sk) ? sk : NULL);
822 local_bh_disable();
823 ctl_sk = this_cpu_read(ipv4_tcp_sk);
824 sock_net_set(ctl_sk, net);
825 if (sk) {
826 ctl_sk->sk_mark = (sk->sk_state == TCP_TIME_WAIT) ?
827 inet_twsk(sk)->tw_mark : sk->sk_mark;
828 ctl_sk->sk_priority = (sk->sk_state == TCP_TIME_WAIT) ?
829 inet_twsk(sk)->tw_priority : sk->sk_priority;
830 transmit_time = tcp_transmit_time(sk);
831 xfrm_sk_clone_policy(ctl_sk, sk);
832 }
833 ip_send_unicast_reply(ctl_sk,
834 skb, &TCP_SKB_CB(skb)->header.h4.opt,
835 ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
836 &arg, arg.iov[0].iov_len,
837 transmit_time);
838
839 ctl_sk->sk_mark = 0;
840 xfrm_sk_free_policy(ctl_sk);
841 sock_net_set(ctl_sk, &init_net);
842 __TCP_INC_STATS(net, TCP_MIB_OUTSEGS);
843 __TCP_INC_STATS(net, TCP_MIB_OUTRSTS);
844 local_bh_enable();
845
846#ifdef CONFIG_TCP_MD5SIG
847out:
848 rcu_read_unlock();
849#endif
850}
851
852/* The code following below sending ACKs in SYN-RECV and TIME-WAIT states
853 outside socket context is ugly, certainly. What can I do?
854 */
855
856static void tcp_v4_send_ack(const struct sock *sk,
857 struct sk_buff *skb, u32 seq, u32 ack,
858 u32 win, u32 tsval, u32 tsecr, int oif,
859 struct tcp_md5sig_key *key,
860 int reply_flags, u8 tos)
861{
862 const struct tcphdr *th = tcp_hdr(skb);
863 struct {
864 struct tcphdr th;
865 __be32 opt[(TCPOLEN_TSTAMP_ALIGNED >> 2)
866#ifdef CONFIG_TCP_MD5SIG
867 + (TCPOLEN_MD5SIG_ALIGNED >> 2)
868#endif
869 ];
870 } rep;
871 struct net *net = sock_net(sk);
872 struct ip_reply_arg arg;
873 struct sock *ctl_sk;
874 u64 transmit_time;
875
876 memset(&rep.th, 0, sizeof(struct tcphdr));
877 memset(&arg, 0, sizeof(arg));
878
879 arg.iov[0].iov_base = (unsigned char *)&rep;
880 arg.iov[0].iov_len = sizeof(rep.th);
881 if (tsecr) {
882 rep.opt[0] = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
883 (TCPOPT_TIMESTAMP << 8) |
884 TCPOLEN_TIMESTAMP);
885 rep.opt[1] = htonl(tsval);
886 rep.opt[2] = htonl(tsecr);
887 arg.iov[0].iov_len += TCPOLEN_TSTAMP_ALIGNED;
888 }
889
890 /* Swap the send and the receive. */
891 rep.th.dest = th->source;
892 rep.th.source = th->dest;
893 rep.th.doff = arg.iov[0].iov_len / 4;
894 rep.th.seq = htonl(seq);
895 rep.th.ack_seq = htonl(ack);
896 rep.th.ack = 1;
897 rep.th.window = htons(win);
898
899#ifdef CONFIG_TCP_MD5SIG
900 if (key) {
901 int offset = (tsecr) ? 3 : 0;
902
903 rep.opt[offset++] = htonl((TCPOPT_NOP << 24) |
904 (TCPOPT_NOP << 16) |
905 (TCPOPT_MD5SIG << 8) |
906 TCPOLEN_MD5SIG);
907 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED;
908 rep.th.doff = arg.iov[0].iov_len/4;
909
910 tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[offset],
911 key, ip_hdr(skb)->saddr,
912 ip_hdr(skb)->daddr, &rep.th);
913 }
914#endif
915 arg.flags = reply_flags;
916 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
917 ip_hdr(skb)->saddr, /* XXX */
918 arg.iov[0].iov_len, IPPROTO_TCP, 0);
919 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
920 if (oif)
921 arg.bound_dev_if = oif;
922 arg.tos = tos;
923 arg.uid = sock_net_uid(net, sk_fullsock(sk) ? sk : NULL);
924 local_bh_disable();
925 ctl_sk = this_cpu_read(ipv4_tcp_sk);
926 sock_net_set(ctl_sk, net);
927 ctl_sk->sk_mark = (sk->sk_state == TCP_TIME_WAIT) ?
928 inet_twsk(sk)->tw_mark : sk->sk_mark;
929 ctl_sk->sk_priority = (sk->sk_state == TCP_TIME_WAIT) ?
930 inet_twsk(sk)->tw_priority : sk->sk_priority;
931 transmit_time = tcp_transmit_time(sk);
932 ip_send_unicast_reply(ctl_sk,
933 skb, &TCP_SKB_CB(skb)->header.h4.opt,
934 ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
935 &arg, arg.iov[0].iov_len,
936 transmit_time);
937
938 ctl_sk->sk_mark = 0;
939 sock_net_set(ctl_sk, &init_net);
940 __TCP_INC_STATS(net, TCP_MIB_OUTSEGS);
941 local_bh_enable();
942}
943
944static void tcp_v4_timewait_ack(struct sock *sk, struct sk_buff *skb)
945{
946 struct inet_timewait_sock *tw = inet_twsk(sk);
947 struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
948
949 tcp_v4_send_ack(sk, skb,
950 tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
951 tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
952 tcp_time_stamp_raw() + tcptw->tw_ts_offset,
953 tcptw->tw_ts_recent,
954 tw->tw_bound_dev_if,
955 tcp_twsk_md5_key(tcptw),
956 tw->tw_transparent ? IP_REPLY_ARG_NOSRCCHECK : 0,
957 tw->tw_tos
958 );
959
960 inet_twsk_put(tw);
961}
962
963static void tcp_v4_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb,
964 struct request_sock *req)
965{
966 const union tcp_md5_addr *addr;
967 int l3index;
968
969 /* sk->sk_state == TCP_LISTEN -> for regular TCP_SYN_RECV
970 * sk->sk_state == TCP_SYN_RECV -> for Fast Open.
971 */
972 u32 seq = (sk->sk_state == TCP_LISTEN) ? tcp_rsk(req)->snt_isn + 1 :
973 tcp_sk(sk)->snd_nxt;
974
975 /* RFC 7323 2.3
976 * The window field (SEG.WND) of every outgoing segment, with the
977 * exception of <SYN> segments, MUST be right-shifted by
978 * Rcv.Wind.Shift bits:
979 */
980 addr = (union tcp_md5_addr *)&ip_hdr(skb)->saddr;
981 l3index = tcp_v4_sdif(skb) ? inet_iif(skb) : 0;
982 tcp_v4_send_ack(sk, skb, seq,
983 tcp_rsk(req)->rcv_nxt,
984 req->rsk_rcv_wnd >> inet_rsk(req)->rcv_wscale,
985 tcp_time_stamp_raw() + tcp_rsk(req)->ts_off,
986 req->ts_recent,
987 0,
988 tcp_md5_do_lookup(sk, l3index, addr, AF_INET),
989 inet_rsk(req)->no_srccheck ? IP_REPLY_ARG_NOSRCCHECK : 0,
990 ip_hdr(skb)->tos);
991}
992
993/*
994 * Send a SYN-ACK after having received a SYN.
995 * This still operates on a request_sock only, not on a big
996 * socket.
997 */
998static int tcp_v4_send_synack(const struct sock *sk, struct dst_entry *dst,
999 struct flowi *fl,
1000 struct request_sock *req,
1001 struct tcp_fastopen_cookie *foc,
1002 enum tcp_synack_type synack_type,
1003 struct sk_buff *syn_skb)
1004{
1005 const struct inet_request_sock *ireq = inet_rsk(req);
1006 struct flowi4 fl4;
1007 int err = -1;
1008 struct sk_buff *skb;
1009 u8 tos;
1010
1011 /* First, grab a route. */
1012 if (!dst && (dst = inet_csk_route_req(sk, &fl4, req)) == NULL)
1013 return -1;
1014
1015 skb = tcp_make_synack(sk, dst, req, foc, synack_type, syn_skb);
1016
1017 if (skb) {
1018 __tcp_v4_send_check(skb, ireq->ir_loc_addr, ireq->ir_rmt_addr);
1019
1020 tos = READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_reflect_tos) ?
1021 (tcp_rsk(req)->syn_tos & ~INET_ECN_MASK) |
1022 (inet_sk(sk)->tos & INET_ECN_MASK) :
1023 inet_sk(sk)->tos;
1024
1025 if (!INET_ECN_is_capable(tos) &&
1026 tcp_bpf_ca_needs_ecn((struct sock *)req))
1027 tos |= INET_ECN_ECT_0;
1028
1029 rcu_read_lock();
1030 err = ip_build_and_send_pkt(skb, sk, ireq->ir_loc_addr,
1031 ireq->ir_rmt_addr,
1032 rcu_dereference(ireq->ireq_opt),
1033 tos);
1034 rcu_read_unlock();
1035 err = net_xmit_eval(err);
1036 }
1037
1038 return err;
1039}
1040
1041/*
1042 * IPv4 request_sock destructor.
1043 */
1044static void tcp_v4_reqsk_destructor(struct request_sock *req)
1045{
1046 kfree(rcu_dereference_protected(inet_rsk(req)->ireq_opt, 1));
1047}
1048
1049#ifdef CONFIG_TCP_MD5SIG
1050/*
1051 * RFC2385 MD5 checksumming requires a mapping of
1052 * IP address->MD5 Key.
1053 * We need to maintain these in the sk structure.
1054 */
1055
1056DEFINE_STATIC_KEY_DEFERRED_FALSE(tcp_md5_needed, HZ);
1057EXPORT_SYMBOL(tcp_md5_needed);
1058
1059static bool better_md5_match(struct tcp_md5sig_key *old, struct tcp_md5sig_key *new)
1060{
1061 if (!old)
1062 return true;
1063
1064 /* l3index always overrides non-l3index */
1065 if (old->l3index && new->l3index == 0)
1066 return false;
1067 if (old->l3index == 0 && new->l3index)
1068 return true;
1069
1070 return old->prefixlen < new->prefixlen;
1071}
1072
1073/* Find the Key structure for an address. */
1074struct tcp_md5sig_key *__tcp_md5_do_lookup(const struct sock *sk, int l3index,
1075 const union tcp_md5_addr *addr,
1076 int family)
1077{
1078 const struct tcp_sock *tp = tcp_sk(sk);
1079 struct tcp_md5sig_key *key;
1080 const struct tcp_md5sig_info *md5sig;
1081 __be32 mask;
1082 struct tcp_md5sig_key *best_match = NULL;
1083 bool match;
1084
1085 /* caller either holds rcu_read_lock() or socket lock */
1086 md5sig = rcu_dereference_check(tp->md5sig_info,
1087 lockdep_sock_is_held(sk));
1088 if (!md5sig)
1089 return NULL;
1090
1091 hlist_for_each_entry_rcu(key, &md5sig->head, node,
1092 lockdep_sock_is_held(sk)) {
1093 if (key->family != family)
1094 continue;
1095 if (key->flags & TCP_MD5SIG_FLAG_IFINDEX && key->l3index != l3index)
1096 continue;
1097 if (family == AF_INET) {
1098 mask = inet_make_mask(key->prefixlen);
1099 match = (key->addr.a4.s_addr & mask) ==
1100 (addr->a4.s_addr & mask);
1101#if IS_ENABLED(CONFIG_IPV6)
1102 } else if (family == AF_INET6) {
1103 match = ipv6_prefix_equal(&key->addr.a6, &addr->a6,
1104 key->prefixlen);
1105#endif
1106 } else {
1107 match = false;
1108 }
1109
1110 if (match && better_md5_match(best_match, key))
1111 best_match = key;
1112 }
1113 return best_match;
1114}
1115EXPORT_SYMBOL(__tcp_md5_do_lookup);
1116
1117static struct tcp_md5sig_key *tcp_md5_do_lookup_exact(const struct sock *sk,
1118 const union tcp_md5_addr *addr,
1119 int family, u8 prefixlen,
1120 int l3index, u8 flags)
1121{
1122 const struct tcp_sock *tp = tcp_sk(sk);
1123 struct tcp_md5sig_key *key;
1124 unsigned int size = sizeof(struct in_addr);
1125 const struct tcp_md5sig_info *md5sig;
1126
1127 /* caller either holds rcu_read_lock() or socket lock */
1128 md5sig = rcu_dereference_check(tp->md5sig_info,
1129 lockdep_sock_is_held(sk));
1130 if (!md5sig)
1131 return NULL;
1132#if IS_ENABLED(CONFIG_IPV6)
1133 if (family == AF_INET6)
1134 size = sizeof(struct in6_addr);
1135#endif
1136 hlist_for_each_entry_rcu(key, &md5sig->head, node,
1137 lockdep_sock_is_held(sk)) {
1138 if (key->family != family)
1139 continue;
1140 if ((key->flags & TCP_MD5SIG_FLAG_IFINDEX) != (flags & TCP_MD5SIG_FLAG_IFINDEX))
1141 continue;
1142 if (key->l3index != l3index)
1143 continue;
1144 if (!memcmp(&key->addr, addr, size) &&
1145 key->prefixlen == prefixlen)
1146 return key;
1147 }
1148 return NULL;
1149}
1150
1151struct tcp_md5sig_key *tcp_v4_md5_lookup(const struct sock *sk,
1152 const struct sock *addr_sk)
1153{
1154 const union tcp_md5_addr *addr;
1155 int l3index;
1156
1157 l3index = l3mdev_master_ifindex_by_index(sock_net(sk),
1158 addr_sk->sk_bound_dev_if);
1159 addr = (const union tcp_md5_addr *)&addr_sk->sk_daddr;
1160 return tcp_md5_do_lookup(sk, l3index, addr, AF_INET);
1161}
1162EXPORT_SYMBOL(tcp_v4_md5_lookup);
1163
1164static int tcp_md5sig_info_add(struct sock *sk, gfp_t gfp)
1165{
1166 struct tcp_sock *tp = tcp_sk(sk);
1167 struct tcp_md5sig_info *md5sig;
1168
1169 md5sig = kmalloc(sizeof(*md5sig), gfp);
1170 if (!md5sig)
1171 return -ENOMEM;
1172
1173 sk_gso_disable(sk);
1174 INIT_HLIST_HEAD(&md5sig->head);
1175 rcu_assign_pointer(tp->md5sig_info, md5sig);
1176 return 0;
1177}
1178
1179/* This can be called on a newly created socket, from other files */
1180static int __tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr,
1181 int family, u8 prefixlen, int l3index, u8 flags,
1182 const u8 *newkey, u8 newkeylen, gfp_t gfp)
1183{
1184 /* Add Key to the list */
1185 struct tcp_md5sig_key *key;
1186 struct tcp_sock *tp = tcp_sk(sk);
1187 struct tcp_md5sig_info *md5sig;
1188
1189 key = tcp_md5_do_lookup_exact(sk, addr, family, prefixlen, l3index, flags);
1190 if (key) {
1191 /* Pre-existing entry - just update that one.
1192 * Note that the key might be used concurrently.
1193 * data_race() is telling kcsan that we do not care of
1194 * key mismatches, since changing MD5 key on live flows
1195 * can lead to packet drops.
1196 */
1197 data_race(memcpy(key->key, newkey, newkeylen));
1198
1199 /* Pairs with READ_ONCE() in tcp_md5_hash_key().
1200 * Also note that a reader could catch new key->keylen value
1201 * but old key->key[], this is the reason we use __GFP_ZERO
1202 * at sock_kmalloc() time below these lines.
1203 */
1204 WRITE_ONCE(key->keylen, newkeylen);
1205
1206 return 0;
1207 }
1208
1209 md5sig = rcu_dereference_protected(tp->md5sig_info,
1210 lockdep_sock_is_held(sk));
1211
1212 key = sock_kmalloc(sk, sizeof(*key), gfp | __GFP_ZERO);
1213 if (!key)
1214 return -ENOMEM;
1215 if (!tcp_alloc_md5sig_pool()) {
1216 sock_kfree_s(sk, key, sizeof(*key));
1217 return -ENOMEM;
1218 }
1219
1220 memcpy(key->key, newkey, newkeylen);
1221 key->keylen = newkeylen;
1222 key->family = family;
1223 key->prefixlen = prefixlen;
1224 key->l3index = l3index;
1225 key->flags = flags;
1226 memcpy(&key->addr, addr,
1227 (IS_ENABLED(CONFIG_IPV6) && family == AF_INET6) ? sizeof(struct in6_addr) :
1228 sizeof(struct in_addr));
1229 hlist_add_head_rcu(&key->node, &md5sig->head);
1230 return 0;
1231}
1232
1233int tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr,
1234 int family, u8 prefixlen, int l3index, u8 flags,
1235 const u8 *newkey, u8 newkeylen)
1236{
1237 struct tcp_sock *tp = tcp_sk(sk);
1238
1239 if (!rcu_dereference_protected(tp->md5sig_info, lockdep_sock_is_held(sk))) {
1240 if (tcp_md5sig_info_add(sk, GFP_KERNEL))
1241 return -ENOMEM;
1242
1243 if (!static_branch_inc(&tcp_md5_needed.key)) {
1244 struct tcp_md5sig_info *md5sig;
1245
1246 md5sig = rcu_dereference_protected(tp->md5sig_info, lockdep_sock_is_held(sk));
1247 rcu_assign_pointer(tp->md5sig_info, NULL);
1248 kfree_rcu(md5sig, rcu);
1249 return -EUSERS;
1250 }
1251 }
1252
1253 return __tcp_md5_do_add(sk, addr, family, prefixlen, l3index, flags,
1254 newkey, newkeylen, GFP_KERNEL);
1255}
1256EXPORT_SYMBOL(tcp_md5_do_add);
1257
1258int tcp_md5_key_copy(struct sock *sk, const union tcp_md5_addr *addr,
1259 int family, u8 prefixlen, int l3index,
1260 struct tcp_md5sig_key *key)
1261{
1262 struct tcp_sock *tp = tcp_sk(sk);
1263
1264 if (!rcu_dereference_protected(tp->md5sig_info, lockdep_sock_is_held(sk))) {
1265 if (tcp_md5sig_info_add(sk, sk_gfp_mask(sk, GFP_ATOMIC)))
1266 return -ENOMEM;
1267
1268 if (!static_key_fast_inc_not_disabled(&tcp_md5_needed.key.key)) {
1269 struct tcp_md5sig_info *md5sig;
1270
1271 md5sig = rcu_dereference_protected(tp->md5sig_info, lockdep_sock_is_held(sk));
1272 net_warn_ratelimited("Too many TCP-MD5 keys in the system\n");
1273 rcu_assign_pointer(tp->md5sig_info, NULL);
1274 kfree_rcu(md5sig, rcu);
1275 return -EUSERS;
1276 }
1277 }
1278
1279 return __tcp_md5_do_add(sk, addr, family, prefixlen, l3index,
1280 key->flags, key->key, key->keylen,
1281 sk_gfp_mask(sk, GFP_ATOMIC));
1282}
1283EXPORT_SYMBOL(tcp_md5_key_copy);
1284
1285int tcp_md5_do_del(struct sock *sk, const union tcp_md5_addr *addr, int family,
1286 u8 prefixlen, int l3index, u8 flags)
1287{
1288 struct tcp_md5sig_key *key;
1289
1290 key = tcp_md5_do_lookup_exact(sk, addr, family, prefixlen, l3index, flags);
1291 if (!key)
1292 return -ENOENT;
1293 hlist_del_rcu(&key->node);
1294 atomic_sub(sizeof(*key), &sk->sk_omem_alloc);
1295 kfree_rcu(key, rcu);
1296 return 0;
1297}
1298EXPORT_SYMBOL(tcp_md5_do_del);
1299
1300static void tcp_clear_md5_list(struct sock *sk)
1301{
1302 struct tcp_sock *tp = tcp_sk(sk);
1303 struct tcp_md5sig_key *key;
1304 struct hlist_node *n;
1305 struct tcp_md5sig_info *md5sig;
1306
1307 md5sig = rcu_dereference_protected(tp->md5sig_info, 1);
1308
1309 hlist_for_each_entry_safe(key, n, &md5sig->head, node) {
1310 hlist_del_rcu(&key->node);
1311 atomic_sub(sizeof(*key), &sk->sk_omem_alloc);
1312 kfree_rcu(key, rcu);
1313 }
1314}
1315
1316static int tcp_v4_parse_md5_keys(struct sock *sk, int optname,
1317 sockptr_t optval, int optlen)
1318{
1319 struct tcp_md5sig cmd;
1320 struct sockaddr_in *sin = (struct sockaddr_in *)&cmd.tcpm_addr;
1321 const union tcp_md5_addr *addr;
1322 u8 prefixlen = 32;
1323 int l3index = 0;
1324 u8 flags;
1325
1326 if (optlen < sizeof(cmd))
1327 return -EINVAL;
1328
1329 if (copy_from_sockptr(&cmd, optval, sizeof(cmd)))
1330 return -EFAULT;
1331
1332 if (sin->sin_family != AF_INET)
1333 return -EINVAL;
1334
1335 flags = cmd.tcpm_flags & TCP_MD5SIG_FLAG_IFINDEX;
1336
1337 if (optname == TCP_MD5SIG_EXT &&
1338 cmd.tcpm_flags & TCP_MD5SIG_FLAG_PREFIX) {
1339 prefixlen = cmd.tcpm_prefixlen;
1340 if (prefixlen > 32)
1341 return -EINVAL;
1342 }
1343
1344 if (optname == TCP_MD5SIG_EXT && cmd.tcpm_ifindex &&
1345 cmd.tcpm_flags & TCP_MD5SIG_FLAG_IFINDEX) {
1346 struct net_device *dev;
1347
1348 rcu_read_lock();
1349 dev = dev_get_by_index_rcu(sock_net(sk), cmd.tcpm_ifindex);
1350 if (dev && netif_is_l3_master(dev))
1351 l3index = dev->ifindex;
1352
1353 rcu_read_unlock();
1354
1355 /* ok to reference set/not set outside of rcu;
1356 * right now device MUST be an L3 master
1357 */
1358 if (!dev || !l3index)
1359 return -EINVAL;
1360 }
1361
1362 addr = (union tcp_md5_addr *)&sin->sin_addr.s_addr;
1363
1364 if (!cmd.tcpm_keylen)
1365 return tcp_md5_do_del(sk, addr, AF_INET, prefixlen, l3index, flags);
1366
1367 if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN)
1368 return -EINVAL;
1369
1370 return tcp_md5_do_add(sk, addr, AF_INET, prefixlen, l3index, flags,
1371 cmd.tcpm_key, cmd.tcpm_keylen);
1372}
1373
1374static int tcp_v4_md5_hash_headers(struct tcp_md5sig_pool *hp,
1375 __be32 daddr, __be32 saddr,
1376 const struct tcphdr *th, int nbytes)
1377{
1378 struct tcp4_pseudohdr *bp;
1379 struct scatterlist sg;
1380 struct tcphdr *_th;
1381
1382 bp = hp->scratch;
1383 bp->saddr = saddr;
1384 bp->daddr = daddr;
1385 bp->pad = 0;
1386 bp->protocol = IPPROTO_TCP;
1387 bp->len = cpu_to_be16(nbytes);
1388
1389 _th = (struct tcphdr *)(bp + 1);
1390 memcpy(_th, th, sizeof(*th));
1391 _th->check = 0;
1392
1393 sg_init_one(&sg, bp, sizeof(*bp) + sizeof(*th));
1394 ahash_request_set_crypt(hp->md5_req, &sg, NULL,
1395 sizeof(*bp) + sizeof(*th));
1396 return crypto_ahash_update(hp->md5_req);
1397}
1398
1399static int tcp_v4_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key,
1400 __be32 daddr, __be32 saddr, const struct tcphdr *th)
1401{
1402 struct tcp_md5sig_pool *hp;
1403 struct ahash_request *req;
1404
1405 hp = tcp_get_md5sig_pool();
1406 if (!hp)
1407 goto clear_hash_noput;
1408 req = hp->md5_req;
1409
1410 if (crypto_ahash_init(req))
1411 goto clear_hash;
1412 if (tcp_v4_md5_hash_headers(hp, daddr, saddr, th, th->doff << 2))
1413 goto clear_hash;
1414 if (tcp_md5_hash_key(hp, key))
1415 goto clear_hash;
1416 ahash_request_set_crypt(req, NULL, md5_hash, 0);
1417 if (crypto_ahash_final(req))
1418 goto clear_hash;
1419
1420 tcp_put_md5sig_pool();
1421 return 0;
1422
1423clear_hash:
1424 tcp_put_md5sig_pool();
1425clear_hash_noput:
1426 memset(md5_hash, 0, 16);
1427 return 1;
1428}
1429
1430int tcp_v4_md5_hash_skb(char *md5_hash, const struct tcp_md5sig_key *key,
1431 const struct sock *sk,
1432 const struct sk_buff *skb)
1433{
1434 struct tcp_md5sig_pool *hp;
1435 struct ahash_request *req;
1436 const struct tcphdr *th = tcp_hdr(skb);
1437 __be32 saddr, daddr;
1438
1439 if (sk) { /* valid for establish/request sockets */
1440 saddr = sk->sk_rcv_saddr;
1441 daddr = sk->sk_daddr;
1442 } else {
1443 const struct iphdr *iph = ip_hdr(skb);
1444 saddr = iph->saddr;
1445 daddr = iph->daddr;
1446 }
1447
1448 hp = tcp_get_md5sig_pool();
1449 if (!hp)
1450 goto clear_hash_noput;
1451 req = hp->md5_req;
1452
1453 if (crypto_ahash_init(req))
1454 goto clear_hash;
1455
1456 if (tcp_v4_md5_hash_headers(hp, daddr, saddr, th, skb->len))
1457 goto clear_hash;
1458 if (tcp_md5_hash_skb_data(hp, skb, th->doff << 2))
1459 goto clear_hash;
1460 if (tcp_md5_hash_key(hp, key))
1461 goto clear_hash;
1462 ahash_request_set_crypt(req, NULL, md5_hash, 0);
1463 if (crypto_ahash_final(req))
1464 goto clear_hash;
1465
1466 tcp_put_md5sig_pool();
1467 return 0;
1468
1469clear_hash:
1470 tcp_put_md5sig_pool();
1471clear_hash_noput:
1472 memset(md5_hash, 0, 16);
1473 return 1;
1474}
1475EXPORT_SYMBOL(tcp_v4_md5_hash_skb);
1476
1477#endif
1478
1479static void tcp_v4_init_req(struct request_sock *req,
1480 const struct sock *sk_listener,
1481 struct sk_buff *skb)
1482{
1483 struct inet_request_sock *ireq = inet_rsk(req);
1484 struct net *net = sock_net(sk_listener);
1485
1486 sk_rcv_saddr_set(req_to_sk(req), ip_hdr(skb)->daddr);
1487 sk_daddr_set(req_to_sk(req), ip_hdr(skb)->saddr);
1488 RCU_INIT_POINTER(ireq->ireq_opt, tcp_v4_save_options(net, skb));
1489}
1490
1491static struct dst_entry *tcp_v4_route_req(const struct sock *sk,
1492 struct sk_buff *skb,
1493 struct flowi *fl,
1494 struct request_sock *req)
1495{
1496 tcp_v4_init_req(req, sk, skb);
1497
1498 if (security_inet_conn_request(sk, skb, req))
1499 return NULL;
1500
1501 return inet_csk_route_req(sk, &fl->u.ip4, req);
1502}
1503
1504struct request_sock_ops tcp_request_sock_ops __read_mostly = {
1505 .family = PF_INET,
1506 .obj_size = sizeof(struct tcp_request_sock),
1507 .rtx_syn_ack = tcp_rtx_synack,
1508 .send_ack = tcp_v4_reqsk_send_ack,
1509 .destructor = tcp_v4_reqsk_destructor,
1510 .send_reset = tcp_v4_send_reset,
1511 .syn_ack_timeout = tcp_syn_ack_timeout,
1512};
1513
1514const struct tcp_request_sock_ops tcp_request_sock_ipv4_ops = {
1515 .mss_clamp = TCP_MSS_DEFAULT,
1516#ifdef CONFIG_TCP_MD5SIG
1517 .req_md5_lookup = tcp_v4_md5_lookup,
1518 .calc_md5_hash = tcp_v4_md5_hash_skb,
1519#endif
1520#ifdef CONFIG_SYN_COOKIES
1521 .cookie_init_seq = cookie_v4_init_sequence,
1522#endif
1523 .route_req = tcp_v4_route_req,
1524 .init_seq = tcp_v4_init_seq,
1525 .init_ts_off = tcp_v4_init_ts_off,
1526 .send_synack = tcp_v4_send_synack,
1527};
1528
1529int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
1530{
1531 /* Never answer to SYNs send to broadcast or multicast */
1532 if (skb_rtable(skb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
1533 goto drop;
1534
1535 return tcp_conn_request(&tcp_request_sock_ops,
1536 &tcp_request_sock_ipv4_ops, sk, skb);
1537
1538drop:
1539 tcp_listendrop(sk);
1540 return 0;
1541}
1542EXPORT_SYMBOL(tcp_v4_conn_request);
1543
1544
1545/*
1546 * The three way handshake has completed - we got a valid synack -
1547 * now create the new socket.
1548 */
1549struct sock *tcp_v4_syn_recv_sock(const struct sock *sk, struct sk_buff *skb,
1550 struct request_sock *req,
1551 struct dst_entry *dst,
1552 struct request_sock *req_unhash,
1553 bool *own_req)
1554{
1555 struct inet_request_sock *ireq;
1556 bool found_dup_sk = false;
1557 struct inet_sock *newinet;
1558 struct tcp_sock *newtp;
1559 struct sock *newsk;
1560#ifdef CONFIG_TCP_MD5SIG
1561 const union tcp_md5_addr *addr;
1562 struct tcp_md5sig_key *key;
1563 int l3index;
1564#endif
1565 struct ip_options_rcu *inet_opt;
1566
1567 if (sk_acceptq_is_full(sk))
1568 goto exit_overflow;
1569
1570 newsk = tcp_create_openreq_child(sk, req, skb);
1571 if (!newsk)
1572 goto exit_nonewsk;
1573
1574 newsk->sk_gso_type = SKB_GSO_TCPV4;
1575 inet_sk_rx_dst_set(newsk, skb);
1576
1577 newtp = tcp_sk(newsk);
1578 newinet = inet_sk(newsk);
1579 ireq = inet_rsk(req);
1580 sk_daddr_set(newsk, ireq->ir_rmt_addr);
1581 sk_rcv_saddr_set(newsk, ireq->ir_loc_addr);
1582 newsk->sk_bound_dev_if = ireq->ir_iif;
1583 newinet->inet_saddr = ireq->ir_loc_addr;
1584 inet_opt = rcu_dereference(ireq->ireq_opt);
1585 RCU_INIT_POINTER(newinet->inet_opt, inet_opt);
1586 newinet->mc_index = inet_iif(skb);
1587 newinet->mc_ttl = ip_hdr(skb)->ttl;
1588 newinet->rcv_tos = ip_hdr(skb)->tos;
1589 inet_csk(newsk)->icsk_ext_hdr_len = 0;
1590 if (inet_opt)
1591 inet_csk(newsk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
1592 newinet->inet_id = get_random_u16();
1593
1594 /* Set ToS of the new socket based upon the value of incoming SYN.
1595 * ECT bits are set later in tcp_init_transfer().
1596 */
1597 if (READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_reflect_tos))
1598 newinet->tos = tcp_rsk(req)->syn_tos & ~INET_ECN_MASK;
1599
1600 if (!dst) {
1601 dst = inet_csk_route_child_sock(sk, newsk, req);
1602 if (!dst)
1603 goto put_and_exit;
1604 } else {
1605 /* syncookie case : see end of cookie_v4_check() */
1606 }
1607 sk_setup_caps(newsk, dst);
1608
1609 tcp_ca_openreq_child(newsk, dst);
1610
1611 tcp_sync_mss(newsk, dst_mtu(dst));
1612 newtp->advmss = tcp_mss_clamp(tcp_sk(sk), dst_metric_advmss(dst));
1613
1614 tcp_initialize_rcv_mss(newsk);
1615
1616#ifdef CONFIG_TCP_MD5SIG
1617 l3index = l3mdev_master_ifindex_by_index(sock_net(sk), ireq->ir_iif);
1618 /* Copy over the MD5 key from the original socket */
1619 addr = (union tcp_md5_addr *)&newinet->inet_daddr;
1620 key = tcp_md5_do_lookup(sk, l3index, addr, AF_INET);
1621 if (key) {
1622 if (tcp_md5_key_copy(newsk, addr, AF_INET, 32, l3index, key))
1623 goto put_and_exit;
1624 sk_gso_disable(newsk);
1625 }
1626#endif
1627
1628 if (__inet_inherit_port(sk, newsk) < 0)
1629 goto put_and_exit;
1630 *own_req = inet_ehash_nolisten(newsk, req_to_sk(req_unhash),
1631 &found_dup_sk);
1632 if (likely(*own_req)) {
1633 tcp_move_syn(newtp, req);
1634 ireq->ireq_opt = NULL;
1635 } else {
1636 newinet->inet_opt = NULL;
1637
1638 if (!req_unhash && found_dup_sk) {
1639 /* This code path should only be executed in the
1640 * syncookie case only
1641 */
1642 bh_unlock_sock(newsk);
1643 sock_put(newsk);
1644 newsk = NULL;
1645 }
1646 }
1647 return newsk;
1648
1649exit_overflow:
1650 NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
1651exit_nonewsk:
1652 dst_release(dst);
1653exit:
1654 tcp_listendrop(sk);
1655 return NULL;
1656put_and_exit:
1657 newinet->inet_opt = NULL;
1658 inet_csk_prepare_forced_close(newsk);
1659 tcp_done(newsk);
1660 goto exit;
1661}
1662EXPORT_SYMBOL(tcp_v4_syn_recv_sock);
1663
1664static struct sock *tcp_v4_cookie_check(struct sock *sk, struct sk_buff *skb)
1665{
1666#ifdef CONFIG_SYN_COOKIES
1667 const struct tcphdr *th = tcp_hdr(skb);
1668
1669 if (!th->syn)
1670 sk = cookie_v4_check(sk, skb);
1671#endif
1672 return sk;
1673}
1674
1675u16 tcp_v4_get_syncookie(struct sock *sk, struct iphdr *iph,
1676 struct tcphdr *th, u32 *cookie)
1677{
1678 u16 mss = 0;
1679#ifdef CONFIG_SYN_COOKIES
1680 mss = tcp_get_syncookie_mss(&tcp_request_sock_ops,
1681 &tcp_request_sock_ipv4_ops, sk, th);
1682 if (mss) {
1683 *cookie = __cookie_v4_init_sequence(iph, th, &mss);
1684 tcp_synq_overflow(sk);
1685 }
1686#endif
1687 return mss;
1688}
1689
1690INDIRECT_CALLABLE_DECLARE(struct dst_entry *ipv4_dst_check(struct dst_entry *,
1691 u32));
1692/* The socket must have it's spinlock held when we get
1693 * here, unless it is a TCP_LISTEN socket.
1694 *
1695 * We have a potential double-lock case here, so even when
1696 * doing backlog processing we use the BH locking scheme.
1697 * This is because we cannot sleep with the original spinlock
1698 * held.
1699 */
1700int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
1701{
1702 enum skb_drop_reason reason;
1703 struct sock *rsk;
1704
1705 if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
1706 struct dst_entry *dst;
1707
1708 dst = rcu_dereference_protected(sk->sk_rx_dst,
1709 lockdep_sock_is_held(sk));
1710
1711 sock_rps_save_rxhash(sk, skb);
1712 sk_mark_napi_id(sk, skb);
1713 if (dst) {
1714 if (sk->sk_rx_dst_ifindex != skb->skb_iif ||
1715 !INDIRECT_CALL_1(dst->ops->check, ipv4_dst_check,
1716 dst, 0)) {
1717 RCU_INIT_POINTER(sk->sk_rx_dst, NULL);
1718 dst_release(dst);
1719 }
1720 }
1721 tcp_rcv_established(sk, skb);
1722 return 0;
1723 }
1724
1725 reason = SKB_DROP_REASON_NOT_SPECIFIED;
1726 if (tcp_checksum_complete(skb))
1727 goto csum_err;
1728
1729 if (sk->sk_state == TCP_LISTEN) {
1730 struct sock *nsk = tcp_v4_cookie_check(sk, skb);
1731
1732 if (!nsk)
1733 goto discard;
1734 if (nsk != sk) {
1735 if (tcp_child_process(sk, nsk, skb)) {
1736 rsk = nsk;
1737 goto reset;
1738 }
1739 return 0;
1740 }
1741 } else
1742 sock_rps_save_rxhash(sk, skb);
1743
1744 if (tcp_rcv_state_process(sk, skb)) {
1745 rsk = sk;
1746 goto reset;
1747 }
1748 return 0;
1749
1750reset:
1751 tcp_v4_send_reset(rsk, skb);
1752discard:
1753 kfree_skb_reason(skb, reason);
1754 /* Be careful here. If this function gets more complicated and
1755 * gcc suffers from register pressure on the x86, sk (in %ebx)
1756 * might be destroyed here. This current version compiles correctly,
1757 * but you have been warned.
1758 */
1759 return 0;
1760
1761csum_err:
1762 reason = SKB_DROP_REASON_TCP_CSUM;
1763 trace_tcp_bad_csum(skb);
1764 TCP_INC_STATS(sock_net(sk), TCP_MIB_CSUMERRORS);
1765 TCP_INC_STATS(sock_net(sk), TCP_MIB_INERRS);
1766 goto discard;
1767}
1768EXPORT_SYMBOL(tcp_v4_do_rcv);
1769
1770int tcp_v4_early_demux(struct sk_buff *skb)
1771{
1772 struct net *net = dev_net(skb->dev);
1773 const struct iphdr *iph;
1774 const struct tcphdr *th;
1775 struct sock *sk;
1776
1777 if (skb->pkt_type != PACKET_HOST)
1778 return 0;
1779
1780 if (!pskb_may_pull(skb, skb_transport_offset(skb) + sizeof(struct tcphdr)))
1781 return 0;
1782
1783 iph = ip_hdr(skb);
1784 th = tcp_hdr(skb);
1785
1786 if (th->doff < sizeof(struct tcphdr) / 4)
1787 return 0;
1788
1789 sk = __inet_lookup_established(net, net->ipv4.tcp_death_row.hashinfo,
1790 iph->saddr, th->source,
1791 iph->daddr, ntohs(th->dest),
1792 skb->skb_iif, inet_sdif(skb));
1793 if (sk) {
1794 skb->sk = sk;
1795 skb->destructor = sock_edemux;
1796 if (sk_fullsock(sk)) {
1797 struct dst_entry *dst = rcu_dereference(sk->sk_rx_dst);
1798
1799 if (dst)
1800 dst = dst_check(dst, 0);
1801 if (dst &&
1802 sk->sk_rx_dst_ifindex == skb->skb_iif)
1803 skb_dst_set_noref(skb, dst);
1804 }
1805 }
1806 return 0;
1807}
1808
1809bool tcp_add_backlog(struct sock *sk, struct sk_buff *skb,
1810 enum skb_drop_reason *reason)
1811{
1812 u32 limit, tail_gso_size, tail_gso_segs;
1813 struct skb_shared_info *shinfo;
1814 const struct tcphdr *th;
1815 struct tcphdr *thtail;
1816 struct sk_buff *tail;
1817 unsigned int hdrlen;
1818 bool fragstolen;
1819 u32 gso_segs;
1820 u32 gso_size;
1821 int delta;
1822
1823 /* In case all data was pulled from skb frags (in __pskb_pull_tail()),
1824 * we can fix skb->truesize to its real value to avoid future drops.
1825 * This is valid because skb is not yet charged to the socket.
1826 * It has been noticed pure SACK packets were sometimes dropped
1827 * (if cooked by drivers without copybreak feature).
1828 */
1829 skb_condense(skb);
1830
1831 skb_dst_drop(skb);
1832
1833 if (unlikely(tcp_checksum_complete(skb))) {
1834 bh_unlock_sock(sk);
1835 trace_tcp_bad_csum(skb);
1836 *reason = SKB_DROP_REASON_TCP_CSUM;
1837 __TCP_INC_STATS(sock_net(sk), TCP_MIB_CSUMERRORS);
1838 __TCP_INC_STATS(sock_net(sk), TCP_MIB_INERRS);
1839 return true;
1840 }
1841
1842 /* Attempt coalescing to last skb in backlog, even if we are
1843 * above the limits.
1844 * This is okay because skb capacity is limited to MAX_SKB_FRAGS.
1845 */
1846 th = (const struct tcphdr *)skb->data;
1847 hdrlen = th->doff * 4;
1848
1849 tail = sk->sk_backlog.tail;
1850 if (!tail)
1851 goto no_coalesce;
1852 thtail = (struct tcphdr *)tail->data;
1853
1854 if (TCP_SKB_CB(tail)->end_seq != TCP_SKB_CB(skb)->seq ||
1855 TCP_SKB_CB(tail)->ip_dsfield != TCP_SKB_CB(skb)->ip_dsfield ||
1856 ((TCP_SKB_CB(tail)->tcp_flags |
1857 TCP_SKB_CB(skb)->tcp_flags) & (TCPHDR_SYN | TCPHDR_RST | TCPHDR_URG)) ||
1858 !((TCP_SKB_CB(tail)->tcp_flags &
1859 TCP_SKB_CB(skb)->tcp_flags) & TCPHDR_ACK) ||
1860 ((TCP_SKB_CB(tail)->tcp_flags ^
1861 TCP_SKB_CB(skb)->tcp_flags) & (TCPHDR_ECE | TCPHDR_CWR)) ||
1862#ifdef CONFIG_TLS_DEVICE
1863 tail->decrypted != skb->decrypted ||
1864#endif
1865 thtail->doff != th->doff ||
1866 memcmp(thtail + 1, th + 1, hdrlen - sizeof(*th)))
1867 goto no_coalesce;
1868
1869 __skb_pull(skb, hdrlen);
1870
1871 shinfo = skb_shinfo(skb);
1872 gso_size = shinfo->gso_size ?: skb->len;
1873 gso_segs = shinfo->gso_segs ?: 1;
1874
1875 shinfo = skb_shinfo(tail);
1876 tail_gso_size = shinfo->gso_size ?: (tail->len - hdrlen);
1877 tail_gso_segs = shinfo->gso_segs ?: 1;
1878
1879 if (skb_try_coalesce(tail, skb, &fragstolen, &delta)) {
1880 TCP_SKB_CB(tail)->end_seq = TCP_SKB_CB(skb)->end_seq;
1881
1882 if (likely(!before(TCP_SKB_CB(skb)->ack_seq, TCP_SKB_CB(tail)->ack_seq))) {
1883 TCP_SKB_CB(tail)->ack_seq = TCP_SKB_CB(skb)->ack_seq;
1884 thtail->window = th->window;
1885 }
1886
1887 /* We have to update both TCP_SKB_CB(tail)->tcp_flags and
1888 * thtail->fin, so that the fast path in tcp_rcv_established()
1889 * is not entered if we append a packet with a FIN.
1890 * SYN, RST, URG are not present.
1891 * ACK is set on both packets.
1892 * PSH : we do not really care in TCP stack,
1893 * at least for 'GRO' packets.
1894 */
1895 thtail->fin |= th->fin;
1896 TCP_SKB_CB(tail)->tcp_flags |= TCP_SKB_CB(skb)->tcp_flags;
1897
1898 if (TCP_SKB_CB(skb)->has_rxtstamp) {
1899 TCP_SKB_CB(tail)->has_rxtstamp = true;
1900 tail->tstamp = skb->tstamp;
1901 skb_hwtstamps(tail)->hwtstamp = skb_hwtstamps(skb)->hwtstamp;
1902 }
1903
1904 /* Not as strict as GRO. We only need to carry mss max value */
1905 shinfo->gso_size = max(gso_size, tail_gso_size);
1906 shinfo->gso_segs = min_t(u32, gso_segs + tail_gso_segs, 0xFFFF);
1907
1908 sk->sk_backlog.len += delta;
1909 __NET_INC_STATS(sock_net(sk),
1910 LINUX_MIB_TCPBACKLOGCOALESCE);
1911 kfree_skb_partial(skb, fragstolen);
1912 return false;
1913 }
1914 __skb_push(skb, hdrlen);
1915
1916no_coalesce:
1917 limit = (u32)READ_ONCE(sk->sk_rcvbuf) + (u32)(READ_ONCE(sk->sk_sndbuf) >> 1);
1918
1919 /* Only socket owner can try to collapse/prune rx queues
1920 * to reduce memory overhead, so add a little headroom here.
1921 * Few sockets backlog are possibly concurrently non empty.
1922 */
1923 limit += 64 * 1024;
1924
1925 if (unlikely(sk_add_backlog(sk, skb, limit))) {
1926 bh_unlock_sock(sk);
1927 *reason = SKB_DROP_REASON_SOCKET_BACKLOG;
1928 __NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPBACKLOGDROP);
1929 return true;
1930 }
1931 return false;
1932}
1933EXPORT_SYMBOL(tcp_add_backlog);
1934
1935int tcp_filter(struct sock *sk, struct sk_buff *skb)
1936{
1937 struct tcphdr *th = (struct tcphdr *)skb->data;
1938
1939 return sk_filter_trim_cap(sk, skb, th->doff * 4);
1940}
1941EXPORT_SYMBOL(tcp_filter);
1942
1943static void tcp_v4_restore_cb(struct sk_buff *skb)
1944{
1945 memmove(IPCB(skb), &TCP_SKB_CB(skb)->header.h4,
1946 sizeof(struct inet_skb_parm));
1947}
1948
1949static void tcp_v4_fill_cb(struct sk_buff *skb, const struct iphdr *iph,
1950 const struct tcphdr *th)
1951{
1952 /* This is tricky : We move IPCB at its correct location into TCP_SKB_CB()
1953 * barrier() makes sure compiler wont play fool^Waliasing games.
1954 */
1955 memmove(&TCP_SKB_CB(skb)->header.h4, IPCB(skb),
1956 sizeof(struct inet_skb_parm));
1957 barrier();
1958
1959 TCP_SKB_CB(skb)->seq = ntohl(th->seq);
1960 TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
1961 skb->len - th->doff * 4);
1962 TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
1963 TCP_SKB_CB(skb)->tcp_flags = tcp_flag_byte(th);
1964 TCP_SKB_CB(skb)->tcp_tw_isn = 0;
1965 TCP_SKB_CB(skb)->ip_dsfield = ipv4_get_dsfield(iph);
1966 TCP_SKB_CB(skb)->sacked = 0;
1967 TCP_SKB_CB(skb)->has_rxtstamp =
1968 skb->tstamp || skb_hwtstamps(skb)->hwtstamp;
1969}
1970
1971/*
1972 * From tcp_input.c
1973 */
1974
1975int tcp_v4_rcv(struct sk_buff *skb)
1976{
1977 struct net *net = dev_net(skb->dev);
1978 enum skb_drop_reason drop_reason;
1979 int sdif = inet_sdif(skb);
1980 int dif = inet_iif(skb);
1981 const struct iphdr *iph;
1982 const struct tcphdr *th;
1983 bool refcounted;
1984 struct sock *sk;
1985 int ret;
1986
1987 drop_reason = SKB_DROP_REASON_NOT_SPECIFIED;
1988 if (skb->pkt_type != PACKET_HOST)
1989 goto discard_it;
1990
1991 /* Count it even if it's bad */
1992 __TCP_INC_STATS(net, TCP_MIB_INSEGS);
1993
1994 if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
1995 goto discard_it;
1996
1997 th = (const struct tcphdr *)skb->data;
1998
1999 if (unlikely(th->doff < sizeof(struct tcphdr) / 4)) {
2000 drop_reason = SKB_DROP_REASON_PKT_TOO_SMALL;
2001 goto bad_packet;
2002 }
2003 if (!pskb_may_pull(skb, th->doff * 4))
2004 goto discard_it;
2005
2006 /* An explanation is required here, I think.
2007 * Packet length and doff are validated by header prediction,
2008 * provided case of th->doff==0 is eliminated.
2009 * So, we defer the checks. */
2010
2011 if (skb_checksum_init(skb, IPPROTO_TCP, inet_compute_pseudo))
2012 goto csum_error;
2013
2014 th = (const struct tcphdr *)skb->data;
2015 iph = ip_hdr(skb);
2016lookup:
2017 sk = __inet_lookup_skb(net->ipv4.tcp_death_row.hashinfo,
2018 skb, __tcp_hdrlen(th), th->source,
2019 th->dest, sdif, &refcounted);
2020 if (!sk)
2021 goto no_tcp_socket;
2022
2023process:
2024 if (sk->sk_state == TCP_TIME_WAIT)
2025 goto do_time_wait;
2026
2027 if (sk->sk_state == TCP_NEW_SYN_RECV) {
2028 struct request_sock *req = inet_reqsk(sk);
2029 bool req_stolen = false;
2030 struct sock *nsk;
2031
2032 sk = req->rsk_listener;
2033 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
2034 drop_reason = SKB_DROP_REASON_XFRM_POLICY;
2035 else
2036 drop_reason = tcp_inbound_md5_hash(sk, skb,
2037 &iph->saddr, &iph->daddr,
2038 AF_INET, dif, sdif);
2039 if (unlikely(drop_reason)) {
2040 sk_drops_add(sk, skb);
2041 reqsk_put(req);
2042 goto discard_it;
2043 }
2044 if (tcp_checksum_complete(skb)) {
2045 reqsk_put(req);
2046 goto csum_error;
2047 }
2048 if (unlikely(sk->sk_state != TCP_LISTEN)) {
2049 nsk = reuseport_migrate_sock(sk, req_to_sk(req), skb);
2050 if (!nsk) {
2051 inet_csk_reqsk_queue_drop_and_put(sk, req);
2052 goto lookup;
2053 }
2054 sk = nsk;
2055 /* reuseport_migrate_sock() has already held one sk_refcnt
2056 * before returning.
2057 */
2058 } else {
2059 /* We own a reference on the listener, increase it again
2060 * as we might lose it too soon.
2061 */
2062 sock_hold(sk);
2063 }
2064 refcounted = true;
2065 nsk = NULL;
2066 if (!tcp_filter(sk, skb)) {
2067 th = (const struct tcphdr *)skb->data;
2068 iph = ip_hdr(skb);
2069 tcp_v4_fill_cb(skb, iph, th);
2070 nsk = tcp_check_req(sk, skb, req, false, &req_stolen);
2071 } else {
2072 drop_reason = SKB_DROP_REASON_SOCKET_FILTER;
2073 }
2074 if (!nsk) {
2075 reqsk_put(req);
2076 if (req_stolen) {
2077 /* Another cpu got exclusive access to req
2078 * and created a full blown socket.
2079 * Try to feed this packet to this socket
2080 * instead of discarding it.
2081 */
2082 tcp_v4_restore_cb(skb);
2083 sock_put(sk);
2084 goto lookup;
2085 }
2086 goto discard_and_relse;
2087 }
2088 nf_reset_ct(skb);
2089 if (nsk == sk) {
2090 reqsk_put(req);
2091 tcp_v4_restore_cb(skb);
2092 } else if (tcp_child_process(sk, nsk, skb)) {
2093 tcp_v4_send_reset(nsk, skb);
2094 goto discard_and_relse;
2095 } else {
2096 sock_put(sk);
2097 return 0;
2098 }
2099 }
2100
2101 if (static_branch_unlikely(&ip4_min_ttl)) {
2102 /* min_ttl can be changed concurrently from do_ip_setsockopt() */
2103 if (unlikely(iph->ttl < READ_ONCE(inet_sk(sk)->min_ttl))) {
2104 __NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP);
2105 goto discard_and_relse;
2106 }
2107 }
2108
2109 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb)) {
2110 drop_reason = SKB_DROP_REASON_XFRM_POLICY;
2111 goto discard_and_relse;
2112 }
2113
2114 drop_reason = tcp_inbound_md5_hash(sk, skb, &iph->saddr,
2115 &iph->daddr, AF_INET, dif, sdif);
2116 if (drop_reason)
2117 goto discard_and_relse;
2118
2119 nf_reset_ct(skb);
2120
2121 if (tcp_filter(sk, skb)) {
2122 drop_reason = SKB_DROP_REASON_SOCKET_FILTER;
2123 goto discard_and_relse;
2124 }
2125 th = (const struct tcphdr *)skb->data;
2126 iph = ip_hdr(skb);
2127 tcp_v4_fill_cb(skb, iph, th);
2128
2129 skb->dev = NULL;
2130
2131 if (sk->sk_state == TCP_LISTEN) {
2132 ret = tcp_v4_do_rcv(sk, skb);
2133 goto put_and_return;
2134 }
2135
2136 sk_incoming_cpu_update(sk);
2137
2138 bh_lock_sock_nested(sk);
2139 tcp_segs_in(tcp_sk(sk), skb);
2140 ret = 0;
2141 if (!sock_owned_by_user(sk)) {
2142 ret = tcp_v4_do_rcv(sk, skb);
2143 } else {
2144 if (tcp_add_backlog(sk, skb, &drop_reason))
2145 goto discard_and_relse;
2146 }
2147 bh_unlock_sock(sk);
2148
2149put_and_return:
2150 if (refcounted)
2151 sock_put(sk);
2152
2153 return ret;
2154
2155no_tcp_socket:
2156 drop_reason = SKB_DROP_REASON_NO_SOCKET;
2157 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
2158 goto discard_it;
2159
2160 tcp_v4_fill_cb(skb, iph, th);
2161
2162 if (tcp_checksum_complete(skb)) {
2163csum_error:
2164 drop_reason = SKB_DROP_REASON_TCP_CSUM;
2165 trace_tcp_bad_csum(skb);
2166 __TCP_INC_STATS(net, TCP_MIB_CSUMERRORS);
2167bad_packet:
2168 __TCP_INC_STATS(net, TCP_MIB_INERRS);
2169 } else {
2170 tcp_v4_send_reset(NULL, skb);
2171 }
2172
2173discard_it:
2174 SKB_DR_OR(drop_reason, NOT_SPECIFIED);
2175 /* Discard frame. */
2176 kfree_skb_reason(skb, drop_reason);
2177 return 0;
2178
2179discard_and_relse:
2180 sk_drops_add(sk, skb);
2181 if (refcounted)
2182 sock_put(sk);
2183 goto discard_it;
2184
2185do_time_wait:
2186 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
2187 drop_reason = SKB_DROP_REASON_XFRM_POLICY;
2188 inet_twsk_put(inet_twsk(sk));
2189 goto discard_it;
2190 }
2191
2192 tcp_v4_fill_cb(skb, iph, th);
2193
2194 if (tcp_checksum_complete(skb)) {
2195 inet_twsk_put(inet_twsk(sk));
2196 goto csum_error;
2197 }
2198 switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) {
2199 case TCP_TW_SYN: {
2200 struct sock *sk2 = inet_lookup_listener(net,
2201 net->ipv4.tcp_death_row.hashinfo,
2202 skb, __tcp_hdrlen(th),
2203 iph->saddr, th->source,
2204 iph->daddr, th->dest,
2205 inet_iif(skb),
2206 sdif);
2207 if (sk2) {
2208 inet_twsk_deschedule_put(inet_twsk(sk));
2209 sk = sk2;
2210 tcp_v4_restore_cb(skb);
2211 refcounted = false;
2212 goto process;
2213 }
2214 }
2215 /* to ACK */
2216 fallthrough;
2217 case TCP_TW_ACK:
2218 tcp_v4_timewait_ack(sk, skb);
2219 break;
2220 case TCP_TW_RST:
2221 tcp_v4_send_reset(sk, skb);
2222 inet_twsk_deschedule_put(inet_twsk(sk));
2223 goto discard_it;
2224 case TCP_TW_SUCCESS:;
2225 }
2226 goto discard_it;
2227}
2228
2229static struct timewait_sock_ops tcp_timewait_sock_ops = {
2230 .twsk_obj_size = sizeof(struct tcp_timewait_sock),
2231 .twsk_unique = tcp_twsk_unique,
2232 .twsk_destructor= tcp_twsk_destructor,
2233};
2234
2235void inet_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb)
2236{
2237 struct dst_entry *dst = skb_dst(skb);
2238
2239 if (dst && dst_hold_safe(dst)) {
2240 rcu_assign_pointer(sk->sk_rx_dst, dst);
2241 sk->sk_rx_dst_ifindex = skb->skb_iif;
2242 }
2243}
2244EXPORT_SYMBOL(inet_sk_rx_dst_set);
2245
2246const struct inet_connection_sock_af_ops ipv4_specific = {
2247 .queue_xmit = ip_queue_xmit,
2248 .send_check = tcp_v4_send_check,
2249 .rebuild_header = inet_sk_rebuild_header,
2250 .sk_rx_dst_set = inet_sk_rx_dst_set,
2251 .conn_request = tcp_v4_conn_request,
2252 .syn_recv_sock = tcp_v4_syn_recv_sock,
2253 .net_header_len = sizeof(struct iphdr),
2254 .setsockopt = ip_setsockopt,
2255 .getsockopt = ip_getsockopt,
2256 .addr2sockaddr = inet_csk_addr2sockaddr,
2257 .sockaddr_len = sizeof(struct sockaddr_in),
2258 .mtu_reduced = tcp_v4_mtu_reduced,
2259};
2260EXPORT_SYMBOL(ipv4_specific);
2261
2262#ifdef CONFIG_TCP_MD5SIG
2263static const struct tcp_sock_af_ops tcp_sock_ipv4_specific = {
2264 .md5_lookup = tcp_v4_md5_lookup,
2265 .calc_md5_hash = tcp_v4_md5_hash_skb,
2266 .md5_parse = tcp_v4_parse_md5_keys,
2267};
2268#endif
2269
2270/* NOTE: A lot of things set to zero explicitly by call to
2271 * sk_alloc() so need not be done here.
2272 */
2273static int tcp_v4_init_sock(struct sock *sk)
2274{
2275 struct inet_connection_sock *icsk = inet_csk(sk);
2276
2277 tcp_init_sock(sk);
2278
2279 icsk->icsk_af_ops = &ipv4_specific;
2280
2281#ifdef CONFIG_TCP_MD5SIG
2282 tcp_sk(sk)->af_specific = &tcp_sock_ipv4_specific;
2283#endif
2284
2285 return 0;
2286}
2287
2288void tcp_v4_destroy_sock(struct sock *sk)
2289{
2290 struct tcp_sock *tp = tcp_sk(sk);
2291
2292 trace_tcp_destroy_sock(sk);
2293
2294 tcp_clear_xmit_timers(sk);
2295
2296 tcp_cleanup_congestion_control(sk);
2297
2298 tcp_cleanup_ulp(sk);
2299
2300 /* Cleanup up the write buffer. */
2301 tcp_write_queue_purge(sk);
2302
2303 /* Check if we want to disable active TFO */
2304 tcp_fastopen_active_disable_ofo_check(sk);
2305
2306 /* Cleans up our, hopefully empty, out_of_order_queue. */
2307 skb_rbtree_purge(&tp->out_of_order_queue);
2308
2309#ifdef CONFIG_TCP_MD5SIG
2310 /* Clean up the MD5 key list, if any */
2311 if (tp->md5sig_info) {
2312 tcp_clear_md5_list(sk);
2313 kfree_rcu(rcu_dereference_protected(tp->md5sig_info, 1), rcu);
2314 tp->md5sig_info = NULL;
2315 static_branch_slow_dec_deferred(&tcp_md5_needed);
2316 }
2317#endif
2318
2319 /* Clean up a referenced TCP bind bucket. */
2320 if (inet_csk(sk)->icsk_bind_hash)
2321 inet_put_port(sk);
2322
2323 BUG_ON(rcu_access_pointer(tp->fastopen_rsk));
2324
2325 /* If socket is aborted during connect operation */
2326 tcp_free_fastopen_req(tp);
2327 tcp_fastopen_destroy_cipher(sk);
2328 tcp_saved_syn_free(tp);
2329
2330 sk_sockets_allocated_dec(sk);
2331}
2332EXPORT_SYMBOL(tcp_v4_destroy_sock);
2333
2334#ifdef CONFIG_PROC_FS
2335/* Proc filesystem TCP sock list dumping. */
2336
2337static unsigned short seq_file_family(const struct seq_file *seq);
2338
2339static bool seq_sk_match(struct seq_file *seq, const struct sock *sk)
2340{
2341 unsigned short family = seq_file_family(seq);
2342
2343 /* AF_UNSPEC is used as a match all */
2344 return ((family == AF_UNSPEC || family == sk->sk_family) &&
2345 net_eq(sock_net(sk), seq_file_net(seq)));
2346}
2347
2348/* Find a non empty bucket (starting from st->bucket)
2349 * and return the first sk from it.
2350 */
2351static void *listening_get_first(struct seq_file *seq)
2352{
2353 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo;
2354 struct tcp_iter_state *st = seq->private;
2355
2356 st->offset = 0;
2357 for (; st->bucket <= hinfo->lhash2_mask; st->bucket++) {
2358 struct inet_listen_hashbucket *ilb2;
2359 struct hlist_nulls_node *node;
2360 struct sock *sk;
2361
2362 ilb2 = &hinfo->lhash2[st->bucket];
2363 if (hlist_nulls_empty(&ilb2->nulls_head))
2364 continue;
2365
2366 spin_lock(&ilb2->lock);
2367 sk_nulls_for_each(sk, node, &ilb2->nulls_head) {
2368 if (seq_sk_match(seq, sk))
2369 return sk;
2370 }
2371 spin_unlock(&ilb2->lock);
2372 }
2373
2374 return NULL;
2375}
2376
2377/* Find the next sk of "cur" within the same bucket (i.e. st->bucket).
2378 * If "cur" is the last one in the st->bucket,
2379 * call listening_get_first() to return the first sk of the next
2380 * non empty bucket.
2381 */
2382static void *listening_get_next(struct seq_file *seq, void *cur)
2383{
2384 struct tcp_iter_state *st = seq->private;
2385 struct inet_listen_hashbucket *ilb2;
2386 struct hlist_nulls_node *node;
2387 struct inet_hashinfo *hinfo;
2388 struct sock *sk = cur;
2389
2390 ++st->num;
2391 ++st->offset;
2392
2393 sk = sk_nulls_next(sk);
2394 sk_nulls_for_each_from(sk, node) {
2395 if (seq_sk_match(seq, sk))
2396 return sk;
2397 }
2398
2399 hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo;
2400 ilb2 = &hinfo->lhash2[st->bucket];
2401 spin_unlock(&ilb2->lock);
2402 ++st->bucket;
2403 return listening_get_first(seq);
2404}
2405
2406static void *listening_get_idx(struct seq_file *seq, loff_t *pos)
2407{
2408 struct tcp_iter_state *st = seq->private;
2409 void *rc;
2410
2411 st->bucket = 0;
2412 st->offset = 0;
2413 rc = listening_get_first(seq);
2414
2415 while (rc && *pos) {
2416 rc = listening_get_next(seq, rc);
2417 --*pos;
2418 }
2419 return rc;
2420}
2421
2422static inline bool empty_bucket(struct inet_hashinfo *hinfo,
2423 const struct tcp_iter_state *st)
2424{
2425 return hlist_nulls_empty(&hinfo->ehash[st->bucket].chain);
2426}
2427
2428/*
2429 * Get first established socket starting from bucket given in st->bucket.
2430 * If st->bucket is zero, the very first socket in the hash is returned.
2431 */
2432static void *established_get_first(struct seq_file *seq)
2433{
2434 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo;
2435 struct tcp_iter_state *st = seq->private;
2436
2437 st->offset = 0;
2438 for (; st->bucket <= hinfo->ehash_mask; ++st->bucket) {
2439 struct sock *sk;
2440 struct hlist_nulls_node *node;
2441 spinlock_t *lock = inet_ehash_lockp(hinfo, st->bucket);
2442
2443 /* Lockless fast path for the common case of empty buckets */
2444 if (empty_bucket(hinfo, st))
2445 continue;
2446
2447 spin_lock_bh(lock);
2448 sk_nulls_for_each(sk, node, &hinfo->ehash[st->bucket].chain) {
2449 if (seq_sk_match(seq, sk))
2450 return sk;
2451 }
2452 spin_unlock_bh(lock);
2453 }
2454
2455 return NULL;
2456}
2457
2458static void *established_get_next(struct seq_file *seq, void *cur)
2459{
2460 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo;
2461 struct tcp_iter_state *st = seq->private;
2462 struct hlist_nulls_node *node;
2463 struct sock *sk = cur;
2464
2465 ++st->num;
2466 ++st->offset;
2467
2468 sk = sk_nulls_next(sk);
2469
2470 sk_nulls_for_each_from(sk, node) {
2471 if (seq_sk_match(seq, sk))
2472 return sk;
2473 }
2474
2475 spin_unlock_bh(inet_ehash_lockp(hinfo, st->bucket));
2476 ++st->bucket;
2477 return established_get_first(seq);
2478}
2479
2480static void *established_get_idx(struct seq_file *seq, loff_t pos)
2481{
2482 struct tcp_iter_state *st = seq->private;
2483 void *rc;
2484
2485 st->bucket = 0;
2486 rc = established_get_first(seq);
2487
2488 while (rc && pos) {
2489 rc = established_get_next(seq, rc);
2490 --pos;
2491 }
2492 return rc;
2493}
2494
2495static void *tcp_get_idx(struct seq_file *seq, loff_t pos)
2496{
2497 void *rc;
2498 struct tcp_iter_state *st = seq->private;
2499
2500 st->state = TCP_SEQ_STATE_LISTENING;
2501 rc = listening_get_idx(seq, &pos);
2502
2503 if (!rc) {
2504 st->state = TCP_SEQ_STATE_ESTABLISHED;
2505 rc = established_get_idx(seq, pos);
2506 }
2507
2508 return rc;
2509}
2510
2511static void *tcp_seek_last_pos(struct seq_file *seq)
2512{
2513 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo;
2514 struct tcp_iter_state *st = seq->private;
2515 int bucket = st->bucket;
2516 int offset = st->offset;
2517 int orig_num = st->num;
2518 void *rc = NULL;
2519
2520 switch (st->state) {
2521 case TCP_SEQ_STATE_LISTENING:
2522 if (st->bucket > hinfo->lhash2_mask)
2523 break;
2524 rc = listening_get_first(seq);
2525 while (offset-- && rc && bucket == st->bucket)
2526 rc = listening_get_next(seq, rc);
2527 if (rc)
2528 break;
2529 st->bucket = 0;
2530 st->state = TCP_SEQ_STATE_ESTABLISHED;
2531 fallthrough;
2532 case TCP_SEQ_STATE_ESTABLISHED:
2533 if (st->bucket > hinfo->ehash_mask)
2534 break;
2535 rc = established_get_first(seq);
2536 while (offset-- && rc && bucket == st->bucket)
2537 rc = established_get_next(seq, rc);
2538 }
2539
2540 st->num = orig_num;
2541
2542 return rc;
2543}
2544
2545void *tcp_seq_start(struct seq_file *seq, loff_t *pos)
2546{
2547 struct tcp_iter_state *st = seq->private;
2548 void *rc;
2549
2550 if (*pos && *pos == st->last_pos) {
2551 rc = tcp_seek_last_pos(seq);
2552 if (rc)
2553 goto out;
2554 }
2555
2556 st->state = TCP_SEQ_STATE_LISTENING;
2557 st->num = 0;
2558 st->bucket = 0;
2559 st->offset = 0;
2560 rc = *pos ? tcp_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
2561
2562out:
2563 st->last_pos = *pos;
2564 return rc;
2565}
2566EXPORT_SYMBOL(tcp_seq_start);
2567
2568void *tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2569{
2570 struct tcp_iter_state *st = seq->private;
2571 void *rc = NULL;
2572
2573 if (v == SEQ_START_TOKEN) {
2574 rc = tcp_get_idx(seq, 0);
2575 goto out;
2576 }
2577
2578 switch (st->state) {
2579 case TCP_SEQ_STATE_LISTENING:
2580 rc = listening_get_next(seq, v);
2581 if (!rc) {
2582 st->state = TCP_SEQ_STATE_ESTABLISHED;
2583 st->bucket = 0;
2584 st->offset = 0;
2585 rc = established_get_first(seq);
2586 }
2587 break;
2588 case TCP_SEQ_STATE_ESTABLISHED:
2589 rc = established_get_next(seq, v);
2590 break;
2591 }
2592out:
2593 ++*pos;
2594 st->last_pos = *pos;
2595 return rc;
2596}
2597EXPORT_SYMBOL(tcp_seq_next);
2598
2599void tcp_seq_stop(struct seq_file *seq, void *v)
2600{
2601 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo;
2602 struct tcp_iter_state *st = seq->private;
2603
2604 switch (st->state) {
2605 case TCP_SEQ_STATE_LISTENING:
2606 if (v != SEQ_START_TOKEN)
2607 spin_unlock(&hinfo->lhash2[st->bucket].lock);
2608 break;
2609 case TCP_SEQ_STATE_ESTABLISHED:
2610 if (v)
2611 spin_unlock_bh(inet_ehash_lockp(hinfo, st->bucket));
2612 break;
2613 }
2614}
2615EXPORT_SYMBOL(tcp_seq_stop);
2616
2617static void get_openreq4(const struct request_sock *req,
2618 struct seq_file *f, int i)
2619{
2620 const struct inet_request_sock *ireq = inet_rsk(req);
2621 long delta = req->rsk_timer.expires - jiffies;
2622
2623 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2624 " %02X %08X:%08X %02X:%08lX %08X %5u %8d %u %d %pK",
2625 i,
2626 ireq->ir_loc_addr,
2627 ireq->ir_num,
2628 ireq->ir_rmt_addr,
2629 ntohs(ireq->ir_rmt_port),
2630 TCP_SYN_RECV,
2631 0, 0, /* could print option size, but that is af dependent. */
2632 1, /* timers active (only the expire timer) */
2633 jiffies_delta_to_clock_t(delta),
2634 req->num_timeout,
2635 from_kuid_munged(seq_user_ns(f),
2636 sock_i_uid(req->rsk_listener)),
2637 0, /* non standard timer */
2638 0, /* open_requests have no inode */
2639 0,
2640 req);
2641}
2642
2643static void get_tcp4_sock(struct sock *sk, struct seq_file *f, int i)
2644{
2645 int timer_active;
2646 unsigned long timer_expires;
2647 const struct tcp_sock *tp = tcp_sk(sk);
2648 const struct inet_connection_sock *icsk = inet_csk(sk);
2649 const struct inet_sock *inet = inet_sk(sk);
2650 const struct fastopen_queue *fastopenq = &icsk->icsk_accept_queue.fastopenq;
2651 __be32 dest = inet->inet_daddr;
2652 __be32 src = inet->inet_rcv_saddr;
2653 __u16 destp = ntohs(inet->inet_dport);
2654 __u16 srcp = ntohs(inet->inet_sport);
2655 int rx_queue;
2656 int state;
2657
2658 if (icsk->icsk_pending == ICSK_TIME_RETRANS ||
2659 icsk->icsk_pending == ICSK_TIME_REO_TIMEOUT ||
2660 icsk->icsk_pending == ICSK_TIME_LOSS_PROBE) {
2661 timer_active = 1;
2662 timer_expires = icsk->icsk_timeout;
2663 } else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
2664 timer_active = 4;
2665 timer_expires = icsk->icsk_timeout;
2666 } else if (timer_pending(&sk->sk_timer)) {
2667 timer_active = 2;
2668 timer_expires = sk->sk_timer.expires;
2669 } else {
2670 timer_active = 0;
2671 timer_expires = jiffies;
2672 }
2673
2674 state = inet_sk_state_load(sk);
2675 if (state == TCP_LISTEN)
2676 rx_queue = READ_ONCE(sk->sk_ack_backlog);
2677 else
2678 /* Because we don't lock the socket,
2679 * we might find a transient negative value.
2680 */
2681 rx_queue = max_t(int, READ_ONCE(tp->rcv_nxt) -
2682 READ_ONCE(tp->copied_seq), 0);
2683
2684 seq_printf(f, "%4d: %08X:%04X %08X:%04X %02X %08X:%08X %02X:%08lX "
2685 "%08X %5u %8d %lu %d %pK %lu %lu %u %u %d",
2686 i, src, srcp, dest, destp, state,
2687 READ_ONCE(tp->write_seq) - tp->snd_una,
2688 rx_queue,
2689 timer_active,
2690 jiffies_delta_to_clock_t(timer_expires - jiffies),
2691 icsk->icsk_retransmits,
2692 from_kuid_munged(seq_user_ns(f), sock_i_uid(sk)),
2693 icsk->icsk_probes_out,
2694 sock_i_ino(sk),
2695 refcount_read(&sk->sk_refcnt), sk,
2696 jiffies_to_clock_t(icsk->icsk_rto),
2697 jiffies_to_clock_t(icsk->icsk_ack.ato),
2698 (icsk->icsk_ack.quick << 1) | inet_csk_in_pingpong_mode(sk),
2699 tcp_snd_cwnd(tp),
2700 state == TCP_LISTEN ?
2701 fastopenq->max_qlen :
2702 (tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh));
2703}
2704
2705static void get_timewait4_sock(const struct inet_timewait_sock *tw,
2706 struct seq_file *f, int i)
2707{
2708 long delta = tw->tw_timer.expires - jiffies;
2709 __be32 dest, src;
2710 __u16 destp, srcp;
2711
2712 dest = tw->tw_daddr;
2713 src = tw->tw_rcv_saddr;
2714 destp = ntohs(tw->tw_dport);
2715 srcp = ntohs(tw->tw_sport);
2716
2717 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2718 " %02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK",
2719 i, src, srcp, dest, destp, tw->tw_substate, 0, 0,
2720 3, jiffies_delta_to_clock_t(delta), 0, 0, 0, 0,
2721 refcount_read(&tw->tw_refcnt), tw);
2722}
2723
2724#define TMPSZ 150
2725
2726static int tcp4_seq_show(struct seq_file *seq, void *v)
2727{
2728 struct tcp_iter_state *st;
2729 struct sock *sk = v;
2730
2731 seq_setwidth(seq, TMPSZ - 1);
2732 if (v == SEQ_START_TOKEN) {
2733 seq_puts(seq, " sl local_address rem_address st tx_queue "
2734 "rx_queue tr tm->when retrnsmt uid timeout "
2735 "inode");
2736 goto out;
2737 }
2738 st = seq->private;
2739
2740 if (sk->sk_state == TCP_TIME_WAIT)
2741 get_timewait4_sock(v, seq, st->num);
2742 else if (sk->sk_state == TCP_NEW_SYN_RECV)
2743 get_openreq4(v, seq, st->num);
2744 else
2745 get_tcp4_sock(v, seq, st->num);
2746out:
2747 seq_pad(seq, '\n');
2748 return 0;
2749}
2750
2751#ifdef CONFIG_BPF_SYSCALL
2752struct bpf_tcp_iter_state {
2753 struct tcp_iter_state state;
2754 unsigned int cur_sk;
2755 unsigned int end_sk;
2756 unsigned int max_sk;
2757 struct sock **batch;
2758 bool st_bucket_done;
2759};
2760
2761struct bpf_iter__tcp {
2762 __bpf_md_ptr(struct bpf_iter_meta *, meta);
2763 __bpf_md_ptr(struct sock_common *, sk_common);
2764 uid_t uid __aligned(8);
2765};
2766
2767static int tcp_prog_seq_show(struct bpf_prog *prog, struct bpf_iter_meta *meta,
2768 struct sock_common *sk_common, uid_t uid)
2769{
2770 struct bpf_iter__tcp ctx;
2771
2772 meta->seq_num--; /* skip SEQ_START_TOKEN */
2773 ctx.meta = meta;
2774 ctx.sk_common = sk_common;
2775 ctx.uid = uid;
2776 return bpf_iter_run_prog(prog, &ctx);
2777}
2778
2779static void bpf_iter_tcp_put_batch(struct bpf_tcp_iter_state *iter)
2780{
2781 while (iter->cur_sk < iter->end_sk)
2782 sock_put(iter->batch[iter->cur_sk++]);
2783}
2784
2785static int bpf_iter_tcp_realloc_batch(struct bpf_tcp_iter_state *iter,
2786 unsigned int new_batch_sz)
2787{
2788 struct sock **new_batch;
2789
2790 new_batch = kvmalloc(sizeof(*new_batch) * new_batch_sz,
2791 GFP_USER | __GFP_NOWARN);
2792 if (!new_batch)
2793 return -ENOMEM;
2794
2795 bpf_iter_tcp_put_batch(iter);
2796 kvfree(iter->batch);
2797 iter->batch = new_batch;
2798 iter->max_sk = new_batch_sz;
2799
2800 return 0;
2801}
2802
2803static unsigned int bpf_iter_tcp_listening_batch(struct seq_file *seq,
2804 struct sock *start_sk)
2805{
2806 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo;
2807 struct bpf_tcp_iter_state *iter = seq->private;
2808 struct tcp_iter_state *st = &iter->state;
2809 struct hlist_nulls_node *node;
2810 unsigned int expected = 1;
2811 struct sock *sk;
2812
2813 sock_hold(start_sk);
2814 iter->batch[iter->end_sk++] = start_sk;
2815
2816 sk = sk_nulls_next(start_sk);
2817 sk_nulls_for_each_from(sk, node) {
2818 if (seq_sk_match(seq, sk)) {
2819 if (iter->end_sk < iter->max_sk) {
2820 sock_hold(sk);
2821 iter->batch[iter->end_sk++] = sk;
2822 }
2823 expected++;
2824 }
2825 }
2826 spin_unlock(&hinfo->lhash2[st->bucket].lock);
2827
2828 return expected;
2829}
2830
2831static unsigned int bpf_iter_tcp_established_batch(struct seq_file *seq,
2832 struct sock *start_sk)
2833{
2834 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo;
2835 struct bpf_tcp_iter_state *iter = seq->private;
2836 struct tcp_iter_state *st = &iter->state;
2837 struct hlist_nulls_node *node;
2838 unsigned int expected = 1;
2839 struct sock *sk;
2840
2841 sock_hold(start_sk);
2842 iter->batch[iter->end_sk++] = start_sk;
2843
2844 sk = sk_nulls_next(start_sk);
2845 sk_nulls_for_each_from(sk, node) {
2846 if (seq_sk_match(seq, sk)) {
2847 if (iter->end_sk < iter->max_sk) {
2848 sock_hold(sk);
2849 iter->batch[iter->end_sk++] = sk;
2850 }
2851 expected++;
2852 }
2853 }
2854 spin_unlock_bh(inet_ehash_lockp(hinfo, st->bucket));
2855
2856 return expected;
2857}
2858
2859static struct sock *bpf_iter_tcp_batch(struct seq_file *seq)
2860{
2861 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo;
2862 struct bpf_tcp_iter_state *iter = seq->private;
2863 struct tcp_iter_state *st = &iter->state;
2864 unsigned int expected;
2865 bool resized = false;
2866 struct sock *sk;
2867
2868 /* The st->bucket is done. Directly advance to the next
2869 * bucket instead of having the tcp_seek_last_pos() to skip
2870 * one by one in the current bucket and eventually find out
2871 * it has to advance to the next bucket.
2872 */
2873 if (iter->st_bucket_done) {
2874 st->offset = 0;
2875 st->bucket++;
2876 if (st->state == TCP_SEQ_STATE_LISTENING &&
2877 st->bucket > hinfo->lhash2_mask) {
2878 st->state = TCP_SEQ_STATE_ESTABLISHED;
2879 st->bucket = 0;
2880 }
2881 }
2882
2883again:
2884 /* Get a new batch */
2885 iter->cur_sk = 0;
2886 iter->end_sk = 0;
2887 iter->st_bucket_done = false;
2888
2889 sk = tcp_seek_last_pos(seq);
2890 if (!sk)
2891 return NULL; /* Done */
2892
2893 if (st->state == TCP_SEQ_STATE_LISTENING)
2894 expected = bpf_iter_tcp_listening_batch(seq, sk);
2895 else
2896 expected = bpf_iter_tcp_established_batch(seq, sk);
2897
2898 if (iter->end_sk == expected) {
2899 iter->st_bucket_done = true;
2900 return sk;
2901 }
2902
2903 if (!resized && !bpf_iter_tcp_realloc_batch(iter, expected * 3 / 2)) {
2904 resized = true;
2905 goto again;
2906 }
2907
2908 return sk;
2909}
2910
2911static void *bpf_iter_tcp_seq_start(struct seq_file *seq, loff_t *pos)
2912{
2913 /* bpf iter does not support lseek, so it always
2914 * continue from where it was stop()-ped.
2915 */
2916 if (*pos)
2917 return bpf_iter_tcp_batch(seq);
2918
2919 return SEQ_START_TOKEN;
2920}
2921
2922static void *bpf_iter_tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2923{
2924 struct bpf_tcp_iter_state *iter = seq->private;
2925 struct tcp_iter_state *st = &iter->state;
2926 struct sock *sk;
2927
2928 /* Whenever seq_next() is called, the iter->cur_sk is
2929 * done with seq_show(), so advance to the next sk in
2930 * the batch.
2931 */
2932 if (iter->cur_sk < iter->end_sk) {
2933 /* Keeping st->num consistent in tcp_iter_state.
2934 * bpf_iter_tcp does not use st->num.
2935 * meta.seq_num is used instead.
2936 */
2937 st->num++;
2938 /* Move st->offset to the next sk in the bucket such that
2939 * the future start() will resume at st->offset in
2940 * st->bucket. See tcp_seek_last_pos().
2941 */
2942 st->offset++;
2943 sock_put(iter->batch[iter->cur_sk++]);
2944 }
2945
2946 if (iter->cur_sk < iter->end_sk)
2947 sk = iter->batch[iter->cur_sk];
2948 else
2949 sk = bpf_iter_tcp_batch(seq);
2950
2951 ++*pos;
2952 /* Keeping st->last_pos consistent in tcp_iter_state.
2953 * bpf iter does not do lseek, so st->last_pos always equals to *pos.
2954 */
2955 st->last_pos = *pos;
2956 return sk;
2957}
2958
2959static int bpf_iter_tcp_seq_show(struct seq_file *seq, void *v)
2960{
2961 struct bpf_iter_meta meta;
2962 struct bpf_prog *prog;
2963 struct sock *sk = v;
2964 bool slow;
2965 uid_t uid;
2966 int ret;
2967
2968 if (v == SEQ_START_TOKEN)
2969 return 0;
2970
2971 if (sk_fullsock(sk))
2972 slow = lock_sock_fast(sk);
2973
2974 if (unlikely(sk_unhashed(sk))) {
2975 ret = SEQ_SKIP;
2976 goto unlock;
2977 }
2978
2979 if (sk->sk_state == TCP_TIME_WAIT) {
2980 uid = 0;
2981 } else if (sk->sk_state == TCP_NEW_SYN_RECV) {
2982 const struct request_sock *req = v;
2983
2984 uid = from_kuid_munged(seq_user_ns(seq),
2985 sock_i_uid(req->rsk_listener));
2986 } else {
2987 uid = from_kuid_munged(seq_user_ns(seq), sock_i_uid(sk));
2988 }
2989
2990 meta.seq = seq;
2991 prog = bpf_iter_get_info(&meta, false);
2992 ret = tcp_prog_seq_show(prog, &meta, v, uid);
2993
2994unlock:
2995 if (sk_fullsock(sk))
2996 unlock_sock_fast(sk, slow);
2997 return ret;
2998
2999}
3000
3001static void bpf_iter_tcp_seq_stop(struct seq_file *seq, void *v)
3002{
3003 struct bpf_tcp_iter_state *iter = seq->private;
3004 struct bpf_iter_meta meta;
3005 struct bpf_prog *prog;
3006
3007 if (!v) {
3008 meta.seq = seq;
3009 prog = bpf_iter_get_info(&meta, true);
3010 if (prog)
3011 (void)tcp_prog_seq_show(prog, &meta, v, 0);
3012 }
3013
3014 if (iter->cur_sk < iter->end_sk) {
3015 bpf_iter_tcp_put_batch(iter);
3016 iter->st_bucket_done = false;
3017 }
3018}
3019
3020static const struct seq_operations bpf_iter_tcp_seq_ops = {
3021 .show = bpf_iter_tcp_seq_show,
3022 .start = bpf_iter_tcp_seq_start,
3023 .next = bpf_iter_tcp_seq_next,
3024 .stop = bpf_iter_tcp_seq_stop,
3025};
3026#endif
3027static unsigned short seq_file_family(const struct seq_file *seq)
3028{
3029 const struct tcp_seq_afinfo *afinfo;
3030
3031#ifdef CONFIG_BPF_SYSCALL
3032 /* Iterated from bpf_iter. Let the bpf prog to filter instead. */
3033 if (seq->op == &bpf_iter_tcp_seq_ops)
3034 return AF_UNSPEC;
3035#endif
3036
3037 /* Iterated from proc fs */
3038 afinfo = pde_data(file_inode(seq->file));
3039 return afinfo->family;
3040}
3041
3042static const struct seq_operations tcp4_seq_ops = {
3043 .show = tcp4_seq_show,
3044 .start = tcp_seq_start,
3045 .next = tcp_seq_next,
3046 .stop = tcp_seq_stop,
3047};
3048
3049static struct tcp_seq_afinfo tcp4_seq_afinfo = {
3050 .family = AF_INET,
3051};
3052
3053static int __net_init tcp4_proc_init_net(struct net *net)
3054{
3055 if (!proc_create_net_data("tcp", 0444, net->proc_net, &tcp4_seq_ops,
3056 sizeof(struct tcp_iter_state), &tcp4_seq_afinfo))
3057 return -ENOMEM;
3058 return 0;
3059}
3060
3061static void __net_exit tcp4_proc_exit_net(struct net *net)
3062{
3063 remove_proc_entry("tcp", net->proc_net);
3064}
3065
3066static struct pernet_operations tcp4_net_ops = {
3067 .init = tcp4_proc_init_net,
3068 .exit = tcp4_proc_exit_net,
3069};
3070
3071int __init tcp4_proc_init(void)
3072{
3073 return register_pernet_subsys(&tcp4_net_ops);
3074}
3075
3076void tcp4_proc_exit(void)
3077{
3078 unregister_pernet_subsys(&tcp4_net_ops);
3079}
3080#endif /* CONFIG_PROC_FS */
3081
3082/* @wake is one when sk_stream_write_space() calls us.
3083 * This sends EPOLLOUT only if notsent_bytes is half the limit.
3084 * This mimics the strategy used in sock_def_write_space().
3085 */
3086bool tcp_stream_memory_free(const struct sock *sk, int wake)
3087{
3088 const struct tcp_sock *tp = tcp_sk(sk);
3089 u32 notsent_bytes = READ_ONCE(tp->write_seq) -
3090 READ_ONCE(tp->snd_nxt);
3091
3092 return (notsent_bytes << wake) < tcp_notsent_lowat(tp);
3093}
3094EXPORT_SYMBOL(tcp_stream_memory_free);
3095
3096struct proto tcp_prot = {
3097 .name = "TCP",
3098 .owner = THIS_MODULE,
3099 .close = tcp_close,
3100 .pre_connect = tcp_v4_pre_connect,
3101 .connect = tcp_v4_connect,
3102 .disconnect = tcp_disconnect,
3103 .accept = inet_csk_accept,
3104 .ioctl = tcp_ioctl,
3105 .init = tcp_v4_init_sock,
3106 .destroy = tcp_v4_destroy_sock,
3107 .shutdown = tcp_shutdown,
3108 .setsockopt = tcp_setsockopt,
3109 .getsockopt = tcp_getsockopt,
3110 .bpf_bypass_getsockopt = tcp_bpf_bypass_getsockopt,
3111 .keepalive = tcp_set_keepalive,
3112 .recvmsg = tcp_recvmsg,
3113 .sendmsg = tcp_sendmsg,
3114 .sendpage = tcp_sendpage,
3115 .backlog_rcv = tcp_v4_do_rcv,
3116 .release_cb = tcp_release_cb,
3117 .hash = inet_hash,
3118 .unhash = inet_unhash,
3119 .get_port = inet_csk_get_port,
3120 .put_port = inet_put_port,
3121#ifdef CONFIG_BPF_SYSCALL
3122 .psock_update_sk_prot = tcp_bpf_update_proto,
3123#endif
3124 .enter_memory_pressure = tcp_enter_memory_pressure,
3125 .leave_memory_pressure = tcp_leave_memory_pressure,
3126 .stream_memory_free = tcp_stream_memory_free,
3127 .sockets_allocated = &tcp_sockets_allocated,
3128 .orphan_count = &tcp_orphan_count,
3129
3130 .memory_allocated = &tcp_memory_allocated,
3131 .per_cpu_fw_alloc = &tcp_memory_per_cpu_fw_alloc,
3132
3133 .memory_pressure = &tcp_memory_pressure,
3134 .sysctl_mem = sysctl_tcp_mem,
3135 .sysctl_wmem_offset = offsetof(struct net, ipv4.sysctl_tcp_wmem),
3136 .sysctl_rmem_offset = offsetof(struct net, ipv4.sysctl_tcp_rmem),
3137 .max_header = MAX_TCP_HEADER,
3138 .obj_size = sizeof(struct tcp_sock),
3139 .slab_flags = SLAB_TYPESAFE_BY_RCU,
3140 .twsk_prot = &tcp_timewait_sock_ops,
3141 .rsk_prot = &tcp_request_sock_ops,
3142 .h.hashinfo = NULL,
3143 .no_autobind = true,
3144 .diag_destroy = tcp_abort,
3145};
3146EXPORT_SYMBOL(tcp_prot);
3147
3148static void __net_exit tcp_sk_exit(struct net *net)
3149{
3150 if (net->ipv4.tcp_congestion_control)
3151 bpf_module_put(net->ipv4.tcp_congestion_control,
3152 net->ipv4.tcp_congestion_control->owner);
3153}
3154
3155static void __net_init tcp_set_hashinfo(struct net *net)
3156{
3157 struct inet_hashinfo *hinfo;
3158 unsigned int ehash_entries;
3159 struct net *old_net;
3160
3161 if (net_eq(net, &init_net))
3162 goto fallback;
3163
3164 old_net = current->nsproxy->net_ns;
3165 ehash_entries = READ_ONCE(old_net->ipv4.sysctl_tcp_child_ehash_entries);
3166 if (!ehash_entries)
3167 goto fallback;
3168
3169 ehash_entries = roundup_pow_of_two(ehash_entries);
3170 hinfo = inet_pernet_hashinfo_alloc(&tcp_hashinfo, ehash_entries);
3171 if (!hinfo) {
3172 pr_warn("Failed to allocate TCP ehash (entries: %u) "
3173 "for a netns, fallback to the global one\n",
3174 ehash_entries);
3175fallback:
3176 hinfo = &tcp_hashinfo;
3177 ehash_entries = tcp_hashinfo.ehash_mask + 1;
3178 }
3179
3180 net->ipv4.tcp_death_row.hashinfo = hinfo;
3181 net->ipv4.tcp_death_row.sysctl_max_tw_buckets = ehash_entries / 2;
3182 net->ipv4.sysctl_max_syn_backlog = max(128U, ehash_entries / 128);
3183}
3184
3185static int __net_init tcp_sk_init(struct net *net)
3186{
3187 net->ipv4.sysctl_tcp_ecn = 2;
3188 net->ipv4.sysctl_tcp_ecn_fallback = 1;
3189
3190 net->ipv4.sysctl_tcp_base_mss = TCP_BASE_MSS;
3191 net->ipv4.sysctl_tcp_min_snd_mss = TCP_MIN_SND_MSS;
3192 net->ipv4.sysctl_tcp_probe_threshold = TCP_PROBE_THRESHOLD;
3193 net->ipv4.sysctl_tcp_probe_interval = TCP_PROBE_INTERVAL;
3194 net->ipv4.sysctl_tcp_mtu_probe_floor = TCP_MIN_SND_MSS;
3195
3196 net->ipv4.sysctl_tcp_keepalive_time = TCP_KEEPALIVE_TIME;
3197 net->ipv4.sysctl_tcp_keepalive_probes = TCP_KEEPALIVE_PROBES;
3198 net->ipv4.sysctl_tcp_keepalive_intvl = TCP_KEEPALIVE_INTVL;
3199
3200 net->ipv4.sysctl_tcp_syn_retries = TCP_SYN_RETRIES;
3201 net->ipv4.sysctl_tcp_synack_retries = TCP_SYNACK_RETRIES;
3202 net->ipv4.sysctl_tcp_syncookies = 1;
3203 net->ipv4.sysctl_tcp_reordering = TCP_FASTRETRANS_THRESH;
3204 net->ipv4.sysctl_tcp_retries1 = TCP_RETR1;
3205 net->ipv4.sysctl_tcp_retries2 = TCP_RETR2;
3206 net->ipv4.sysctl_tcp_orphan_retries = 0;
3207 net->ipv4.sysctl_tcp_fin_timeout = TCP_FIN_TIMEOUT;
3208 net->ipv4.sysctl_tcp_notsent_lowat = UINT_MAX;
3209 net->ipv4.sysctl_tcp_tw_reuse = 2;
3210 net->ipv4.sysctl_tcp_no_ssthresh_metrics_save = 1;
3211
3212 refcount_set(&net->ipv4.tcp_death_row.tw_refcount, 1);
3213 tcp_set_hashinfo(net);
3214
3215 net->ipv4.sysctl_tcp_sack = 1;
3216 net->ipv4.sysctl_tcp_window_scaling = 1;
3217 net->ipv4.sysctl_tcp_timestamps = 1;
3218 net->ipv4.sysctl_tcp_early_retrans = 3;
3219 net->ipv4.sysctl_tcp_recovery = TCP_RACK_LOSS_DETECTION;
3220 net->ipv4.sysctl_tcp_slow_start_after_idle = 1; /* By default, RFC2861 behavior. */
3221 net->ipv4.sysctl_tcp_retrans_collapse = 1;
3222 net->ipv4.sysctl_tcp_max_reordering = 300;
3223 net->ipv4.sysctl_tcp_dsack = 1;
3224 net->ipv4.sysctl_tcp_app_win = 31;
3225 net->ipv4.sysctl_tcp_adv_win_scale = 1;
3226 net->ipv4.sysctl_tcp_frto = 2;
3227 net->ipv4.sysctl_tcp_moderate_rcvbuf = 1;
3228 /* This limits the percentage of the congestion window which we
3229 * will allow a single TSO frame to consume. Building TSO frames
3230 * which are too large can cause TCP streams to be bursty.
3231 */
3232 net->ipv4.sysctl_tcp_tso_win_divisor = 3;
3233 /* Default TSQ limit of 16 TSO segments */
3234 net->ipv4.sysctl_tcp_limit_output_bytes = 16 * 65536;
3235
3236 /* rfc5961 challenge ack rate limiting, per net-ns, disabled by default. */
3237 net->ipv4.sysctl_tcp_challenge_ack_limit = INT_MAX;
3238
3239 net->ipv4.sysctl_tcp_min_tso_segs = 2;
3240 net->ipv4.sysctl_tcp_tso_rtt_log = 9; /* 2^9 = 512 usec */
3241 net->ipv4.sysctl_tcp_min_rtt_wlen = 300;
3242 net->ipv4.sysctl_tcp_autocorking = 1;
3243 net->ipv4.sysctl_tcp_invalid_ratelimit = HZ/2;
3244 net->ipv4.sysctl_tcp_pacing_ss_ratio = 200;
3245 net->ipv4.sysctl_tcp_pacing_ca_ratio = 120;
3246 if (net != &init_net) {
3247 memcpy(net->ipv4.sysctl_tcp_rmem,
3248 init_net.ipv4.sysctl_tcp_rmem,
3249 sizeof(init_net.ipv4.sysctl_tcp_rmem));
3250 memcpy(net->ipv4.sysctl_tcp_wmem,
3251 init_net.ipv4.sysctl_tcp_wmem,
3252 sizeof(init_net.ipv4.sysctl_tcp_wmem));
3253 }
3254 net->ipv4.sysctl_tcp_comp_sack_delay_ns = NSEC_PER_MSEC;
3255 net->ipv4.sysctl_tcp_comp_sack_slack_ns = 100 * NSEC_PER_USEC;
3256 net->ipv4.sysctl_tcp_comp_sack_nr = 44;
3257 net->ipv4.sysctl_tcp_fastopen = TFO_CLIENT_ENABLE;
3258 net->ipv4.sysctl_tcp_fastopen_blackhole_timeout = 0;
3259 atomic_set(&net->ipv4.tfo_active_disable_times, 0);
3260
3261 /* Set default values for PLB */
3262 net->ipv4.sysctl_tcp_plb_enabled = 0; /* Disabled by default */
3263 net->ipv4.sysctl_tcp_plb_idle_rehash_rounds = 3;
3264 net->ipv4.sysctl_tcp_plb_rehash_rounds = 12;
3265 net->ipv4.sysctl_tcp_plb_suspend_rto_sec = 60;
3266 /* Default congestion threshold for PLB to mark a round is 50% */
3267 net->ipv4.sysctl_tcp_plb_cong_thresh = (1 << TCP_PLB_SCALE) / 2;
3268
3269 /* Reno is always built in */
3270 if (!net_eq(net, &init_net) &&
3271 bpf_try_module_get(init_net.ipv4.tcp_congestion_control,
3272 init_net.ipv4.tcp_congestion_control->owner))
3273 net->ipv4.tcp_congestion_control = init_net.ipv4.tcp_congestion_control;
3274 else
3275 net->ipv4.tcp_congestion_control = &tcp_reno;
3276
3277 return 0;
3278}
3279
3280static void __net_exit tcp_sk_exit_batch(struct list_head *net_exit_list)
3281{
3282 struct net *net;
3283
3284 tcp_twsk_purge(net_exit_list, AF_INET);
3285
3286 list_for_each_entry(net, net_exit_list, exit_list) {
3287 inet_pernet_hashinfo_free(net->ipv4.tcp_death_row.hashinfo);
3288 WARN_ON_ONCE(!refcount_dec_and_test(&net->ipv4.tcp_death_row.tw_refcount));
3289 tcp_fastopen_ctx_destroy(net);
3290 }
3291}
3292
3293static struct pernet_operations __net_initdata tcp_sk_ops = {
3294 .init = tcp_sk_init,
3295 .exit = tcp_sk_exit,
3296 .exit_batch = tcp_sk_exit_batch,
3297};
3298
3299#if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS)
3300DEFINE_BPF_ITER_FUNC(tcp, struct bpf_iter_meta *meta,
3301 struct sock_common *sk_common, uid_t uid)
3302
3303#define INIT_BATCH_SZ 16
3304
3305static int bpf_iter_init_tcp(void *priv_data, struct bpf_iter_aux_info *aux)
3306{
3307 struct bpf_tcp_iter_state *iter = priv_data;
3308 int err;
3309
3310 err = bpf_iter_init_seq_net(priv_data, aux);
3311 if (err)
3312 return err;
3313
3314 err = bpf_iter_tcp_realloc_batch(iter, INIT_BATCH_SZ);
3315 if (err) {
3316 bpf_iter_fini_seq_net(priv_data);
3317 return err;
3318 }
3319
3320 return 0;
3321}
3322
3323static void bpf_iter_fini_tcp(void *priv_data)
3324{
3325 struct bpf_tcp_iter_state *iter = priv_data;
3326
3327 bpf_iter_fini_seq_net(priv_data);
3328 kvfree(iter->batch);
3329}
3330
3331static const struct bpf_iter_seq_info tcp_seq_info = {
3332 .seq_ops = &bpf_iter_tcp_seq_ops,
3333 .init_seq_private = bpf_iter_init_tcp,
3334 .fini_seq_private = bpf_iter_fini_tcp,
3335 .seq_priv_size = sizeof(struct bpf_tcp_iter_state),
3336};
3337
3338static const struct bpf_func_proto *
3339bpf_iter_tcp_get_func_proto(enum bpf_func_id func_id,
3340 const struct bpf_prog *prog)
3341{
3342 switch (func_id) {
3343 case BPF_FUNC_setsockopt:
3344 return &bpf_sk_setsockopt_proto;
3345 case BPF_FUNC_getsockopt:
3346 return &bpf_sk_getsockopt_proto;
3347 default:
3348 return NULL;
3349 }
3350}
3351
3352static struct bpf_iter_reg tcp_reg_info = {
3353 .target = "tcp",
3354 .ctx_arg_info_size = 1,
3355 .ctx_arg_info = {
3356 { offsetof(struct bpf_iter__tcp, sk_common),
3357 PTR_TO_BTF_ID_OR_NULL },
3358 },
3359 .get_func_proto = bpf_iter_tcp_get_func_proto,
3360 .seq_info = &tcp_seq_info,
3361};
3362
3363static void __init bpf_iter_register(void)
3364{
3365 tcp_reg_info.ctx_arg_info[0].btf_id = btf_sock_ids[BTF_SOCK_TYPE_SOCK_COMMON];
3366 if (bpf_iter_reg_target(&tcp_reg_info))
3367 pr_warn("Warning: could not register bpf iterator tcp\n");
3368}
3369
3370#endif
3371
3372void __init tcp_v4_init(void)
3373{
3374 int cpu, res;
3375
3376 for_each_possible_cpu(cpu) {
3377 struct sock *sk;
3378
3379 res = inet_ctl_sock_create(&sk, PF_INET, SOCK_RAW,
3380 IPPROTO_TCP, &init_net);
3381 if (res)
3382 panic("Failed to create the TCP control socket.\n");
3383 sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
3384
3385 /* Please enforce IP_DF and IPID==0 for RST and
3386 * ACK sent in SYN-RECV and TIME-WAIT state.
3387 */
3388 inet_sk(sk)->pmtudisc = IP_PMTUDISC_DO;
3389
3390 per_cpu(ipv4_tcp_sk, cpu) = sk;
3391 }
3392 if (register_pernet_subsys(&tcp_sk_ops))
3393 panic("Failed to create the TCP control socket.\n");
3394
3395#if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS)
3396 bpf_iter_register();
3397#endif
3398}
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
80#include <crypto/hash.h>
81#include <linux/scatterlist.h>
82
83#include <trace/events/tcp.h>
84
85#ifdef CONFIG_TCP_MD5SIG
86static int tcp_v4_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key,
87 __be32 daddr, __be32 saddr, const struct tcphdr *th);
88#endif
89
90struct inet_hashinfo tcp_hashinfo;
91EXPORT_SYMBOL(tcp_hashinfo);
92
93static u32 tcp_v4_init_seq(const struct sk_buff *skb)
94{
95 return secure_tcp_seq(ip_hdr(skb)->daddr,
96 ip_hdr(skb)->saddr,
97 tcp_hdr(skb)->dest,
98 tcp_hdr(skb)->source);
99}
100
101static u32 tcp_v4_init_ts_off(const struct net *net, const struct sk_buff *skb)
102{
103 return secure_tcp_ts_off(net, ip_hdr(skb)->daddr, ip_hdr(skb)->saddr);
104}
105
106int tcp_twsk_unique(struct sock *sk, struct sock *sktw, void *twp)
107{
108 const struct inet_timewait_sock *tw = inet_twsk(sktw);
109 const struct tcp_timewait_sock *tcptw = tcp_twsk(sktw);
110 struct tcp_sock *tp = tcp_sk(sk);
111 int reuse = sock_net(sk)->ipv4.sysctl_tcp_tw_reuse;
112
113 if (reuse == 2) {
114 /* Still does not detect *everything* that goes through
115 * lo, since we require a loopback src or dst address
116 * or direct binding to 'lo' interface.
117 */
118 bool loopback = false;
119 if (tw->tw_bound_dev_if == LOOPBACK_IFINDEX)
120 loopback = true;
121#if IS_ENABLED(CONFIG_IPV6)
122 if (tw->tw_family == AF_INET6) {
123 if (ipv6_addr_loopback(&tw->tw_v6_daddr) ||
124 (ipv6_addr_v4mapped(&tw->tw_v6_daddr) &&
125 (tw->tw_v6_daddr.s6_addr[12] == 127)) ||
126 ipv6_addr_loopback(&tw->tw_v6_rcv_saddr) ||
127 (ipv6_addr_v4mapped(&tw->tw_v6_rcv_saddr) &&
128 (tw->tw_v6_rcv_saddr.s6_addr[12] == 127)))
129 loopback = true;
130 } else
131#endif
132 {
133 if (ipv4_is_loopback(tw->tw_daddr) ||
134 ipv4_is_loopback(tw->tw_rcv_saddr))
135 loopback = true;
136 }
137 if (!loopback)
138 reuse = 0;
139 }
140
141 /* With PAWS, it is safe from the viewpoint
142 of data integrity. Even without PAWS it is safe provided sequence
143 spaces do not overlap i.e. at data rates <= 80Mbit/sec.
144
145 Actually, the idea is close to VJ's one, only timestamp cache is
146 held not per host, but per port pair and TW bucket is used as state
147 holder.
148
149 If TW bucket has been already destroyed we fall back to VJ's scheme
150 and use initial timestamp retrieved from peer table.
151 */
152 if (tcptw->tw_ts_recent_stamp &&
153 (!twp || (reuse && time_after32(ktime_get_seconds(),
154 tcptw->tw_ts_recent_stamp)))) {
155 /* In case of repair and re-using TIME-WAIT sockets we still
156 * want to be sure that it is safe as above but honor the
157 * sequence numbers and time stamps set as part of the repair
158 * process.
159 *
160 * Without this check re-using a TIME-WAIT socket with TCP
161 * repair would accumulate a -1 on the repair assigned
162 * sequence number. The first time it is reused the sequence
163 * is -1, the second time -2, etc. This fixes that issue
164 * without appearing to create any others.
165 */
166 if (likely(!tp->repair)) {
167 u32 seq = tcptw->tw_snd_nxt + 65535 + 2;
168
169 if (!seq)
170 seq = 1;
171 WRITE_ONCE(tp->write_seq, seq);
172 tp->rx_opt.ts_recent = tcptw->tw_ts_recent;
173 tp->rx_opt.ts_recent_stamp = tcptw->tw_ts_recent_stamp;
174 }
175 sock_hold(sktw);
176 return 1;
177 }
178
179 return 0;
180}
181EXPORT_SYMBOL_GPL(tcp_twsk_unique);
182
183static int tcp_v4_pre_connect(struct sock *sk, struct sockaddr *uaddr,
184 int addr_len)
185{
186 /* This check is replicated from tcp_v4_connect() and intended to
187 * prevent BPF program called below from accessing bytes that are out
188 * of the bound specified by user in addr_len.
189 */
190 if (addr_len < sizeof(struct sockaddr_in))
191 return -EINVAL;
192
193 sock_owned_by_me(sk);
194
195 return BPF_CGROUP_RUN_PROG_INET4_CONNECT(sk, uaddr);
196}
197
198/* This will initiate an outgoing connection. */
199int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
200{
201 struct sockaddr_in *usin = (struct sockaddr_in *)uaddr;
202 struct inet_sock *inet = inet_sk(sk);
203 struct tcp_sock *tp = tcp_sk(sk);
204 __be16 orig_sport, orig_dport;
205 __be32 daddr, nexthop;
206 struct flowi4 *fl4;
207 struct rtable *rt;
208 int err;
209 struct ip_options_rcu *inet_opt;
210 struct inet_timewait_death_row *tcp_death_row = &sock_net(sk)->ipv4.tcp_death_row;
211
212 if (addr_len < sizeof(struct sockaddr_in))
213 return -EINVAL;
214
215 if (usin->sin_family != AF_INET)
216 return -EAFNOSUPPORT;
217
218 nexthop = daddr = usin->sin_addr.s_addr;
219 inet_opt = rcu_dereference_protected(inet->inet_opt,
220 lockdep_sock_is_held(sk));
221 if (inet_opt && inet_opt->opt.srr) {
222 if (!daddr)
223 return -EINVAL;
224 nexthop = inet_opt->opt.faddr;
225 }
226
227 orig_sport = inet->inet_sport;
228 orig_dport = usin->sin_port;
229 fl4 = &inet->cork.fl.u.ip4;
230 rt = ip_route_connect(fl4, nexthop, inet->inet_saddr,
231 RT_CONN_FLAGS(sk), sk->sk_bound_dev_if,
232 IPPROTO_TCP,
233 orig_sport, orig_dport, sk);
234 if (IS_ERR(rt)) {
235 err = PTR_ERR(rt);
236 if (err == -ENETUNREACH)
237 IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTNOROUTES);
238 return err;
239 }
240
241 if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) {
242 ip_rt_put(rt);
243 return -ENETUNREACH;
244 }
245
246 if (!inet_opt || !inet_opt->opt.srr)
247 daddr = fl4->daddr;
248
249 if (!inet->inet_saddr)
250 inet->inet_saddr = fl4->saddr;
251 sk_rcv_saddr_set(sk, inet->inet_saddr);
252
253 if (tp->rx_opt.ts_recent_stamp && inet->inet_daddr != daddr) {
254 /* Reset inherited state */
255 tp->rx_opt.ts_recent = 0;
256 tp->rx_opt.ts_recent_stamp = 0;
257 if (likely(!tp->repair))
258 WRITE_ONCE(tp->write_seq, 0);
259 }
260
261 inet->inet_dport = usin->sin_port;
262 sk_daddr_set(sk, daddr);
263
264 inet_csk(sk)->icsk_ext_hdr_len = 0;
265 if (inet_opt)
266 inet_csk(sk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
267
268 tp->rx_opt.mss_clamp = TCP_MSS_DEFAULT;
269
270 /* Socket identity is still unknown (sport may be zero).
271 * However we set state to SYN-SENT and not releasing socket
272 * lock select source port, enter ourselves into the hash tables and
273 * complete initialization after this.
274 */
275 tcp_set_state(sk, TCP_SYN_SENT);
276 err = inet_hash_connect(tcp_death_row, sk);
277 if (err)
278 goto failure;
279
280 sk_set_txhash(sk);
281
282 rt = ip_route_newports(fl4, rt, orig_sport, orig_dport,
283 inet->inet_sport, inet->inet_dport, sk);
284 if (IS_ERR(rt)) {
285 err = PTR_ERR(rt);
286 rt = NULL;
287 goto failure;
288 }
289 /* OK, now commit destination to socket. */
290 sk->sk_gso_type = SKB_GSO_TCPV4;
291 sk_setup_caps(sk, &rt->dst);
292 rt = NULL;
293
294 if (likely(!tp->repair)) {
295 if (!tp->write_seq)
296 WRITE_ONCE(tp->write_seq,
297 secure_tcp_seq(inet->inet_saddr,
298 inet->inet_daddr,
299 inet->inet_sport,
300 usin->sin_port));
301 tp->tsoffset = secure_tcp_ts_off(sock_net(sk),
302 inet->inet_saddr,
303 inet->inet_daddr);
304 }
305
306 inet->inet_id = prandom_u32();
307
308 if (tcp_fastopen_defer_connect(sk, &err))
309 return err;
310 if (err)
311 goto failure;
312
313 err = tcp_connect(sk);
314
315 if (err)
316 goto failure;
317
318 return 0;
319
320failure:
321 /*
322 * This unhashes the socket and releases the local port,
323 * if necessary.
324 */
325 tcp_set_state(sk, TCP_CLOSE);
326 ip_rt_put(rt);
327 sk->sk_route_caps = 0;
328 inet->inet_dport = 0;
329 return err;
330}
331EXPORT_SYMBOL(tcp_v4_connect);
332
333/*
334 * This routine reacts to ICMP_FRAG_NEEDED mtu indications as defined in RFC1191.
335 * It can be called through tcp_release_cb() if socket was owned by user
336 * at the time tcp_v4_err() was called to handle ICMP message.
337 */
338void tcp_v4_mtu_reduced(struct sock *sk)
339{
340 struct inet_sock *inet = inet_sk(sk);
341 struct dst_entry *dst;
342 u32 mtu;
343
344 if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE))
345 return;
346 mtu = tcp_sk(sk)->mtu_info;
347 dst = inet_csk_update_pmtu(sk, mtu);
348 if (!dst)
349 return;
350
351 /* Something is about to be wrong... Remember soft error
352 * for the case, if this connection will not able to recover.
353 */
354 if (mtu < dst_mtu(dst) && ip_dont_fragment(sk, dst))
355 sk->sk_err_soft = EMSGSIZE;
356
357 mtu = dst_mtu(dst);
358
359 if (inet->pmtudisc != IP_PMTUDISC_DONT &&
360 ip_sk_accept_pmtu(sk) &&
361 inet_csk(sk)->icsk_pmtu_cookie > mtu) {
362 tcp_sync_mss(sk, mtu);
363
364 /* Resend the TCP packet because it's
365 * clear that the old packet has been
366 * dropped. This is the new "fast" path mtu
367 * discovery.
368 */
369 tcp_simple_retransmit(sk);
370 } /* else let the usual retransmit timer handle it */
371}
372EXPORT_SYMBOL(tcp_v4_mtu_reduced);
373
374static void do_redirect(struct sk_buff *skb, struct sock *sk)
375{
376 struct dst_entry *dst = __sk_dst_check(sk, 0);
377
378 if (dst)
379 dst->ops->redirect(dst, sk, skb);
380}
381
382
383/* handle ICMP messages on TCP_NEW_SYN_RECV request sockets */
384void tcp_req_err(struct sock *sk, u32 seq, bool abort)
385{
386 struct request_sock *req = inet_reqsk(sk);
387 struct net *net = sock_net(sk);
388
389 /* ICMPs are not backlogged, hence we cannot get
390 * an established socket here.
391 */
392 if (seq != tcp_rsk(req)->snt_isn) {
393 __NET_INC_STATS(net, LINUX_MIB_OUTOFWINDOWICMPS);
394 } else if (abort) {
395 /*
396 * Still in SYN_RECV, just remove it silently.
397 * There is no good way to pass the error to the newly
398 * created socket, and POSIX does not want network
399 * errors returned from accept().
400 */
401 inet_csk_reqsk_queue_drop(req->rsk_listener, req);
402 tcp_listendrop(req->rsk_listener);
403 }
404 reqsk_put(req);
405}
406EXPORT_SYMBOL(tcp_req_err);
407
408/*
409 * This routine is called by the ICMP module when it gets some
410 * sort of error condition. If err < 0 then the socket should
411 * be closed and the error returned to the user. If err > 0
412 * it's just the icmp type << 8 | icmp code. After adjustment
413 * header points to the first 8 bytes of the tcp header. We need
414 * to find the appropriate port.
415 *
416 * The locking strategy used here is very "optimistic". When
417 * someone else accesses the socket the ICMP is just dropped
418 * and for some paths there is no check at all.
419 * A more general error queue to queue errors for later handling
420 * is probably better.
421 *
422 */
423
424int tcp_v4_err(struct sk_buff *icmp_skb, u32 info)
425{
426 const struct iphdr *iph = (const struct iphdr *)icmp_skb->data;
427 struct tcphdr *th = (struct tcphdr *)(icmp_skb->data + (iph->ihl << 2));
428 struct inet_connection_sock *icsk;
429 struct tcp_sock *tp;
430 struct inet_sock *inet;
431 const int type = icmp_hdr(icmp_skb)->type;
432 const int code = icmp_hdr(icmp_skb)->code;
433 struct sock *sk;
434 struct sk_buff *skb;
435 struct request_sock *fastopen;
436 u32 seq, snd_una;
437 s32 remaining;
438 u32 delta_us;
439 int err;
440 struct net *net = dev_net(icmp_skb->dev);
441
442 sk = __inet_lookup_established(net, &tcp_hashinfo, iph->daddr,
443 th->dest, iph->saddr, ntohs(th->source),
444 inet_iif(icmp_skb), 0);
445 if (!sk) {
446 __ICMP_INC_STATS(net, ICMP_MIB_INERRORS);
447 return -ENOENT;
448 }
449 if (sk->sk_state == TCP_TIME_WAIT) {
450 inet_twsk_put(inet_twsk(sk));
451 return 0;
452 }
453 seq = ntohl(th->seq);
454 if (sk->sk_state == TCP_NEW_SYN_RECV) {
455 tcp_req_err(sk, seq, type == ICMP_PARAMETERPROB ||
456 type == ICMP_TIME_EXCEEDED ||
457 (type == ICMP_DEST_UNREACH &&
458 (code == ICMP_NET_UNREACH ||
459 code == ICMP_HOST_UNREACH)));
460 return 0;
461 }
462
463 bh_lock_sock(sk);
464 /* If too many ICMPs get dropped on busy
465 * servers this needs to be solved differently.
466 * We do take care of PMTU discovery (RFC1191) special case :
467 * we can receive locally generated ICMP messages while socket is held.
468 */
469 if (sock_owned_by_user(sk)) {
470 if (!(type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED))
471 __NET_INC_STATS(net, LINUX_MIB_LOCKDROPPEDICMPS);
472 }
473 if (sk->sk_state == TCP_CLOSE)
474 goto out;
475
476 if (unlikely(iph->ttl < inet_sk(sk)->min_ttl)) {
477 __NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP);
478 goto out;
479 }
480
481 icsk = inet_csk(sk);
482 tp = tcp_sk(sk);
483 /* XXX (TFO) - tp->snd_una should be ISN (tcp_create_openreq_child() */
484 fastopen = rcu_dereference(tp->fastopen_rsk);
485 snd_una = fastopen ? tcp_rsk(fastopen)->snt_isn : tp->snd_una;
486 if (sk->sk_state != TCP_LISTEN &&
487 !between(seq, snd_una, tp->snd_nxt)) {
488 __NET_INC_STATS(net, LINUX_MIB_OUTOFWINDOWICMPS);
489 goto out;
490 }
491
492 switch (type) {
493 case ICMP_REDIRECT:
494 if (!sock_owned_by_user(sk))
495 do_redirect(icmp_skb, sk);
496 goto out;
497 case ICMP_SOURCE_QUENCH:
498 /* Just silently ignore these. */
499 goto out;
500 case ICMP_PARAMETERPROB:
501 err = EPROTO;
502 break;
503 case ICMP_DEST_UNREACH:
504 if (code > NR_ICMP_UNREACH)
505 goto out;
506
507 if (code == ICMP_FRAG_NEEDED) { /* PMTU discovery (RFC1191) */
508 /* We are not interested in TCP_LISTEN and open_requests
509 * (SYN-ACKs send out by Linux are always <576bytes so
510 * they should go through unfragmented).
511 */
512 if (sk->sk_state == TCP_LISTEN)
513 goto out;
514
515 tp->mtu_info = info;
516 if (!sock_owned_by_user(sk)) {
517 tcp_v4_mtu_reduced(sk);
518 } else {
519 if (!test_and_set_bit(TCP_MTU_REDUCED_DEFERRED, &sk->sk_tsq_flags))
520 sock_hold(sk);
521 }
522 goto out;
523 }
524
525 err = icmp_err_convert[code].errno;
526 /* check if icmp_skb allows revert of backoff
527 * (see draft-zimmermann-tcp-lcd) */
528 if (code != ICMP_NET_UNREACH && code != ICMP_HOST_UNREACH)
529 break;
530 if (seq != tp->snd_una || !icsk->icsk_retransmits ||
531 !icsk->icsk_backoff || fastopen)
532 break;
533
534 if (sock_owned_by_user(sk))
535 break;
536
537 skb = tcp_rtx_queue_head(sk);
538 if (WARN_ON_ONCE(!skb))
539 break;
540
541 icsk->icsk_backoff--;
542 icsk->icsk_rto = tp->srtt_us ? __tcp_set_rto(tp) :
543 TCP_TIMEOUT_INIT;
544 icsk->icsk_rto = inet_csk_rto_backoff(icsk, TCP_RTO_MAX);
545
546
547 tcp_mstamp_refresh(tp);
548 delta_us = (u32)(tp->tcp_mstamp - tcp_skb_timestamp_us(skb));
549 remaining = icsk->icsk_rto -
550 usecs_to_jiffies(delta_us);
551
552 if (remaining > 0) {
553 inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
554 remaining, TCP_RTO_MAX);
555 } else {
556 /* RTO revert clocked out retransmission.
557 * Will retransmit now */
558 tcp_retransmit_timer(sk);
559 }
560
561 break;
562 case ICMP_TIME_EXCEEDED:
563 err = EHOSTUNREACH;
564 break;
565 default:
566 goto out;
567 }
568
569 switch (sk->sk_state) {
570 case TCP_SYN_SENT:
571 case TCP_SYN_RECV:
572 /* Only in fast or simultaneous open. If a fast open socket is
573 * is already accepted it is treated as a connected one below.
574 */
575 if (fastopen && !fastopen->sk)
576 break;
577
578 if (!sock_owned_by_user(sk)) {
579 sk->sk_err = err;
580
581 sk->sk_error_report(sk);
582
583 tcp_done(sk);
584 } else {
585 sk->sk_err_soft = err;
586 }
587 goto out;
588 }
589
590 /* If we've already connected we will keep trying
591 * until we time out, or the user gives up.
592 *
593 * rfc1122 4.2.3.9 allows to consider as hard errors
594 * only PROTO_UNREACH and PORT_UNREACH (well, FRAG_FAILED too,
595 * but it is obsoleted by pmtu discovery).
596 *
597 * Note, that in modern internet, where routing is unreliable
598 * and in each dark corner broken firewalls sit, sending random
599 * errors ordered by their masters even this two messages finally lose
600 * their original sense (even Linux sends invalid PORT_UNREACHs)
601 *
602 * Now we are in compliance with RFCs.
603 * --ANK (980905)
604 */
605
606 inet = inet_sk(sk);
607 if (!sock_owned_by_user(sk) && inet->recverr) {
608 sk->sk_err = err;
609 sk->sk_error_report(sk);
610 } else { /* Only an error on timeout */
611 sk->sk_err_soft = err;
612 }
613
614out:
615 bh_unlock_sock(sk);
616 sock_put(sk);
617 return 0;
618}
619
620void __tcp_v4_send_check(struct sk_buff *skb, __be32 saddr, __be32 daddr)
621{
622 struct tcphdr *th = tcp_hdr(skb);
623
624 th->check = ~tcp_v4_check(skb->len, saddr, daddr, 0);
625 skb->csum_start = skb_transport_header(skb) - skb->head;
626 skb->csum_offset = offsetof(struct tcphdr, check);
627}
628
629/* This routine computes an IPv4 TCP checksum. */
630void tcp_v4_send_check(struct sock *sk, struct sk_buff *skb)
631{
632 const struct inet_sock *inet = inet_sk(sk);
633
634 __tcp_v4_send_check(skb, inet->inet_saddr, inet->inet_daddr);
635}
636EXPORT_SYMBOL(tcp_v4_send_check);
637
638/*
639 * This routine will send an RST to the other tcp.
640 *
641 * Someone asks: why I NEVER use socket parameters (TOS, TTL etc.)
642 * for reset.
643 * Answer: if a packet caused RST, it is not for a socket
644 * existing in our system, if it is matched to a socket,
645 * it is just duplicate segment or bug in other side's TCP.
646 * So that we build reply only basing on parameters
647 * arrived with segment.
648 * Exception: precedence violation. We do not implement it in any case.
649 */
650
651static void tcp_v4_send_reset(const struct sock *sk, struct sk_buff *skb)
652{
653 const struct tcphdr *th = tcp_hdr(skb);
654 struct {
655 struct tcphdr th;
656#ifdef CONFIG_TCP_MD5SIG
657 __be32 opt[(TCPOLEN_MD5SIG_ALIGNED >> 2)];
658#endif
659 } rep;
660 struct ip_reply_arg arg;
661#ifdef CONFIG_TCP_MD5SIG
662 struct tcp_md5sig_key *key = NULL;
663 const __u8 *hash_location = NULL;
664 unsigned char newhash[16];
665 int genhash;
666 struct sock *sk1 = NULL;
667#endif
668 u64 transmit_time = 0;
669 struct sock *ctl_sk;
670 struct net *net;
671
672 /* Never send a reset in response to a reset. */
673 if (th->rst)
674 return;
675
676 /* If sk not NULL, it means we did a successful lookup and incoming
677 * route had to be correct. prequeue might have dropped our dst.
678 */
679 if (!sk && skb_rtable(skb)->rt_type != RTN_LOCAL)
680 return;
681
682 /* Swap the send and the receive. */
683 memset(&rep, 0, sizeof(rep));
684 rep.th.dest = th->source;
685 rep.th.source = th->dest;
686 rep.th.doff = sizeof(struct tcphdr) / 4;
687 rep.th.rst = 1;
688
689 if (th->ack) {
690 rep.th.seq = th->ack_seq;
691 } else {
692 rep.th.ack = 1;
693 rep.th.ack_seq = htonl(ntohl(th->seq) + th->syn + th->fin +
694 skb->len - (th->doff << 2));
695 }
696
697 memset(&arg, 0, sizeof(arg));
698 arg.iov[0].iov_base = (unsigned char *)&rep;
699 arg.iov[0].iov_len = sizeof(rep.th);
700
701 net = sk ? sock_net(sk) : dev_net(skb_dst(skb)->dev);
702#ifdef CONFIG_TCP_MD5SIG
703 rcu_read_lock();
704 hash_location = tcp_parse_md5sig_option(th);
705 if (sk && sk_fullsock(sk)) {
706 key = tcp_md5_do_lookup(sk, (union tcp_md5_addr *)
707 &ip_hdr(skb)->saddr, AF_INET);
708 } else if (hash_location) {
709 /*
710 * active side is lost. Try to find listening socket through
711 * source port, and then find md5 key through listening socket.
712 * we are not loose security here:
713 * Incoming packet is checked with md5 hash with finding key,
714 * no RST generated if md5 hash doesn't match.
715 */
716 sk1 = __inet_lookup_listener(net, &tcp_hashinfo, NULL, 0,
717 ip_hdr(skb)->saddr,
718 th->source, ip_hdr(skb)->daddr,
719 ntohs(th->source), inet_iif(skb),
720 tcp_v4_sdif(skb));
721 /* don't send rst if it can't find key */
722 if (!sk1)
723 goto out;
724
725 key = tcp_md5_do_lookup(sk1, (union tcp_md5_addr *)
726 &ip_hdr(skb)->saddr, AF_INET);
727 if (!key)
728 goto out;
729
730
731 genhash = tcp_v4_md5_hash_skb(newhash, key, NULL, skb);
732 if (genhash || memcmp(hash_location, newhash, 16) != 0)
733 goto out;
734
735 }
736
737 if (key) {
738 rep.opt[0] = htonl((TCPOPT_NOP << 24) |
739 (TCPOPT_NOP << 16) |
740 (TCPOPT_MD5SIG << 8) |
741 TCPOLEN_MD5SIG);
742 /* Update length and the length the header thinks exists */
743 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED;
744 rep.th.doff = arg.iov[0].iov_len / 4;
745
746 tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[1],
747 key, ip_hdr(skb)->saddr,
748 ip_hdr(skb)->daddr, &rep.th);
749 }
750#endif
751 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
752 ip_hdr(skb)->saddr, /* XXX */
753 arg.iov[0].iov_len, IPPROTO_TCP, 0);
754 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
755 arg.flags = (sk && inet_sk_transparent(sk)) ? IP_REPLY_ARG_NOSRCCHECK : 0;
756
757 /* When socket is gone, all binding information is lost.
758 * routing might fail in this case. No choice here, if we choose to force
759 * input interface, we will misroute in case of asymmetric route.
760 */
761 if (sk) {
762 arg.bound_dev_if = sk->sk_bound_dev_if;
763 if (sk_fullsock(sk))
764 trace_tcp_send_reset(sk, skb);
765 }
766
767 BUILD_BUG_ON(offsetof(struct sock, sk_bound_dev_if) !=
768 offsetof(struct inet_timewait_sock, tw_bound_dev_if));
769
770 arg.tos = ip_hdr(skb)->tos;
771 arg.uid = sock_net_uid(net, sk && sk_fullsock(sk) ? sk : NULL);
772 local_bh_disable();
773 ctl_sk = this_cpu_read(*net->ipv4.tcp_sk);
774 if (sk) {
775 ctl_sk->sk_mark = (sk->sk_state == TCP_TIME_WAIT) ?
776 inet_twsk(sk)->tw_mark : sk->sk_mark;
777 ctl_sk->sk_priority = (sk->sk_state == TCP_TIME_WAIT) ?
778 inet_twsk(sk)->tw_priority : sk->sk_priority;
779 transmit_time = tcp_transmit_time(sk);
780 }
781 ip_send_unicast_reply(ctl_sk,
782 skb, &TCP_SKB_CB(skb)->header.h4.opt,
783 ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
784 &arg, arg.iov[0].iov_len,
785 transmit_time);
786
787 ctl_sk->sk_mark = 0;
788 __TCP_INC_STATS(net, TCP_MIB_OUTSEGS);
789 __TCP_INC_STATS(net, TCP_MIB_OUTRSTS);
790 local_bh_enable();
791
792#ifdef CONFIG_TCP_MD5SIG
793out:
794 rcu_read_unlock();
795#endif
796}
797
798/* The code following below sending ACKs in SYN-RECV and TIME-WAIT states
799 outside socket context is ugly, certainly. What can I do?
800 */
801
802static void tcp_v4_send_ack(const struct sock *sk,
803 struct sk_buff *skb, u32 seq, u32 ack,
804 u32 win, u32 tsval, u32 tsecr, int oif,
805 struct tcp_md5sig_key *key,
806 int reply_flags, u8 tos)
807{
808 const struct tcphdr *th = tcp_hdr(skb);
809 struct {
810 struct tcphdr th;
811 __be32 opt[(TCPOLEN_TSTAMP_ALIGNED >> 2)
812#ifdef CONFIG_TCP_MD5SIG
813 + (TCPOLEN_MD5SIG_ALIGNED >> 2)
814#endif
815 ];
816 } rep;
817 struct net *net = sock_net(sk);
818 struct ip_reply_arg arg;
819 struct sock *ctl_sk;
820 u64 transmit_time;
821
822 memset(&rep.th, 0, sizeof(struct tcphdr));
823 memset(&arg, 0, sizeof(arg));
824
825 arg.iov[0].iov_base = (unsigned char *)&rep;
826 arg.iov[0].iov_len = sizeof(rep.th);
827 if (tsecr) {
828 rep.opt[0] = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
829 (TCPOPT_TIMESTAMP << 8) |
830 TCPOLEN_TIMESTAMP);
831 rep.opt[1] = htonl(tsval);
832 rep.opt[2] = htonl(tsecr);
833 arg.iov[0].iov_len += TCPOLEN_TSTAMP_ALIGNED;
834 }
835
836 /* Swap the send and the receive. */
837 rep.th.dest = th->source;
838 rep.th.source = th->dest;
839 rep.th.doff = arg.iov[0].iov_len / 4;
840 rep.th.seq = htonl(seq);
841 rep.th.ack_seq = htonl(ack);
842 rep.th.ack = 1;
843 rep.th.window = htons(win);
844
845#ifdef CONFIG_TCP_MD5SIG
846 if (key) {
847 int offset = (tsecr) ? 3 : 0;
848
849 rep.opt[offset++] = htonl((TCPOPT_NOP << 24) |
850 (TCPOPT_NOP << 16) |
851 (TCPOPT_MD5SIG << 8) |
852 TCPOLEN_MD5SIG);
853 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED;
854 rep.th.doff = arg.iov[0].iov_len/4;
855
856 tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[offset],
857 key, ip_hdr(skb)->saddr,
858 ip_hdr(skb)->daddr, &rep.th);
859 }
860#endif
861 arg.flags = reply_flags;
862 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
863 ip_hdr(skb)->saddr, /* XXX */
864 arg.iov[0].iov_len, IPPROTO_TCP, 0);
865 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
866 if (oif)
867 arg.bound_dev_if = oif;
868 arg.tos = tos;
869 arg.uid = sock_net_uid(net, sk_fullsock(sk) ? sk : NULL);
870 local_bh_disable();
871 ctl_sk = this_cpu_read(*net->ipv4.tcp_sk);
872 ctl_sk->sk_mark = (sk->sk_state == TCP_TIME_WAIT) ?
873 inet_twsk(sk)->tw_mark : sk->sk_mark;
874 ctl_sk->sk_priority = (sk->sk_state == TCP_TIME_WAIT) ?
875 inet_twsk(sk)->tw_priority : sk->sk_priority;
876 transmit_time = tcp_transmit_time(sk);
877 ip_send_unicast_reply(ctl_sk,
878 skb, &TCP_SKB_CB(skb)->header.h4.opt,
879 ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
880 &arg, arg.iov[0].iov_len,
881 transmit_time);
882
883 ctl_sk->sk_mark = 0;
884 __TCP_INC_STATS(net, TCP_MIB_OUTSEGS);
885 local_bh_enable();
886}
887
888static void tcp_v4_timewait_ack(struct sock *sk, struct sk_buff *skb)
889{
890 struct inet_timewait_sock *tw = inet_twsk(sk);
891 struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
892
893 tcp_v4_send_ack(sk, skb,
894 tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
895 tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
896 tcp_time_stamp_raw() + tcptw->tw_ts_offset,
897 tcptw->tw_ts_recent,
898 tw->tw_bound_dev_if,
899 tcp_twsk_md5_key(tcptw),
900 tw->tw_transparent ? IP_REPLY_ARG_NOSRCCHECK : 0,
901 tw->tw_tos
902 );
903
904 inet_twsk_put(tw);
905}
906
907static void tcp_v4_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb,
908 struct request_sock *req)
909{
910 /* sk->sk_state == TCP_LISTEN -> for regular TCP_SYN_RECV
911 * sk->sk_state == TCP_SYN_RECV -> for Fast Open.
912 */
913 u32 seq = (sk->sk_state == TCP_LISTEN) ? tcp_rsk(req)->snt_isn + 1 :
914 tcp_sk(sk)->snd_nxt;
915
916 /* RFC 7323 2.3
917 * The window field (SEG.WND) of every outgoing segment, with the
918 * exception of <SYN> segments, MUST be right-shifted by
919 * Rcv.Wind.Shift bits:
920 */
921 tcp_v4_send_ack(sk, skb, seq,
922 tcp_rsk(req)->rcv_nxt,
923 req->rsk_rcv_wnd >> inet_rsk(req)->rcv_wscale,
924 tcp_time_stamp_raw() + tcp_rsk(req)->ts_off,
925 req->ts_recent,
926 0,
927 tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&ip_hdr(skb)->saddr,
928 AF_INET),
929 inet_rsk(req)->no_srccheck ? IP_REPLY_ARG_NOSRCCHECK : 0,
930 ip_hdr(skb)->tos);
931}
932
933/*
934 * Send a SYN-ACK after having received a SYN.
935 * This still operates on a request_sock only, not on a big
936 * socket.
937 */
938static int tcp_v4_send_synack(const struct sock *sk, struct dst_entry *dst,
939 struct flowi *fl,
940 struct request_sock *req,
941 struct tcp_fastopen_cookie *foc,
942 enum tcp_synack_type synack_type)
943{
944 const struct inet_request_sock *ireq = inet_rsk(req);
945 struct flowi4 fl4;
946 int err = -1;
947 struct sk_buff *skb;
948
949 /* First, grab a route. */
950 if (!dst && (dst = inet_csk_route_req(sk, &fl4, req)) == NULL)
951 return -1;
952
953 skb = tcp_make_synack(sk, dst, req, foc, synack_type);
954
955 if (skb) {
956 __tcp_v4_send_check(skb, ireq->ir_loc_addr, ireq->ir_rmt_addr);
957
958 rcu_read_lock();
959 err = ip_build_and_send_pkt(skb, sk, ireq->ir_loc_addr,
960 ireq->ir_rmt_addr,
961 rcu_dereference(ireq->ireq_opt));
962 rcu_read_unlock();
963 err = net_xmit_eval(err);
964 }
965
966 return err;
967}
968
969/*
970 * IPv4 request_sock destructor.
971 */
972static void tcp_v4_reqsk_destructor(struct request_sock *req)
973{
974 kfree(rcu_dereference_protected(inet_rsk(req)->ireq_opt, 1));
975}
976
977#ifdef CONFIG_TCP_MD5SIG
978/*
979 * RFC2385 MD5 checksumming requires a mapping of
980 * IP address->MD5 Key.
981 * We need to maintain these in the sk structure.
982 */
983
984DEFINE_STATIC_KEY_FALSE(tcp_md5_needed);
985EXPORT_SYMBOL(tcp_md5_needed);
986
987/* Find the Key structure for an address. */
988struct tcp_md5sig_key *__tcp_md5_do_lookup(const struct sock *sk,
989 const union tcp_md5_addr *addr,
990 int family)
991{
992 const struct tcp_sock *tp = tcp_sk(sk);
993 struct tcp_md5sig_key *key;
994 const struct tcp_md5sig_info *md5sig;
995 __be32 mask;
996 struct tcp_md5sig_key *best_match = NULL;
997 bool match;
998
999 /* caller either holds rcu_read_lock() or socket lock */
1000 md5sig = rcu_dereference_check(tp->md5sig_info,
1001 lockdep_sock_is_held(sk));
1002 if (!md5sig)
1003 return NULL;
1004
1005 hlist_for_each_entry_rcu(key, &md5sig->head, node) {
1006 if (key->family != family)
1007 continue;
1008
1009 if (family == AF_INET) {
1010 mask = inet_make_mask(key->prefixlen);
1011 match = (key->addr.a4.s_addr & mask) ==
1012 (addr->a4.s_addr & mask);
1013#if IS_ENABLED(CONFIG_IPV6)
1014 } else if (family == AF_INET6) {
1015 match = ipv6_prefix_equal(&key->addr.a6, &addr->a6,
1016 key->prefixlen);
1017#endif
1018 } else {
1019 match = false;
1020 }
1021
1022 if (match && (!best_match ||
1023 key->prefixlen > best_match->prefixlen))
1024 best_match = key;
1025 }
1026 return best_match;
1027}
1028EXPORT_SYMBOL(__tcp_md5_do_lookup);
1029
1030static struct tcp_md5sig_key *tcp_md5_do_lookup_exact(const struct sock *sk,
1031 const union tcp_md5_addr *addr,
1032 int family, u8 prefixlen)
1033{
1034 const struct tcp_sock *tp = tcp_sk(sk);
1035 struct tcp_md5sig_key *key;
1036 unsigned int size = sizeof(struct in_addr);
1037 const struct tcp_md5sig_info *md5sig;
1038
1039 /* caller either holds rcu_read_lock() or socket lock */
1040 md5sig = rcu_dereference_check(tp->md5sig_info,
1041 lockdep_sock_is_held(sk));
1042 if (!md5sig)
1043 return NULL;
1044#if IS_ENABLED(CONFIG_IPV6)
1045 if (family == AF_INET6)
1046 size = sizeof(struct in6_addr);
1047#endif
1048 hlist_for_each_entry_rcu(key, &md5sig->head, node) {
1049 if (key->family != family)
1050 continue;
1051 if (!memcmp(&key->addr, addr, size) &&
1052 key->prefixlen == prefixlen)
1053 return key;
1054 }
1055 return NULL;
1056}
1057
1058struct tcp_md5sig_key *tcp_v4_md5_lookup(const struct sock *sk,
1059 const struct sock *addr_sk)
1060{
1061 const union tcp_md5_addr *addr;
1062
1063 addr = (const union tcp_md5_addr *)&addr_sk->sk_daddr;
1064 return tcp_md5_do_lookup(sk, addr, AF_INET);
1065}
1066EXPORT_SYMBOL(tcp_v4_md5_lookup);
1067
1068/* This can be called on a newly created socket, from other files */
1069int tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr,
1070 int family, u8 prefixlen, const u8 *newkey, u8 newkeylen,
1071 gfp_t gfp)
1072{
1073 /* Add Key to the list */
1074 struct tcp_md5sig_key *key;
1075 struct tcp_sock *tp = tcp_sk(sk);
1076 struct tcp_md5sig_info *md5sig;
1077
1078 key = tcp_md5_do_lookup_exact(sk, addr, family, prefixlen);
1079 if (key) {
1080 /* Pre-existing entry - just update that one. */
1081 memcpy(key->key, newkey, newkeylen);
1082 key->keylen = newkeylen;
1083 return 0;
1084 }
1085
1086 md5sig = rcu_dereference_protected(tp->md5sig_info,
1087 lockdep_sock_is_held(sk));
1088 if (!md5sig) {
1089 md5sig = kmalloc(sizeof(*md5sig), gfp);
1090 if (!md5sig)
1091 return -ENOMEM;
1092
1093 sk_nocaps_add(sk, NETIF_F_GSO_MASK);
1094 INIT_HLIST_HEAD(&md5sig->head);
1095 rcu_assign_pointer(tp->md5sig_info, md5sig);
1096 }
1097
1098 key = sock_kmalloc(sk, sizeof(*key), gfp);
1099 if (!key)
1100 return -ENOMEM;
1101 if (!tcp_alloc_md5sig_pool()) {
1102 sock_kfree_s(sk, key, sizeof(*key));
1103 return -ENOMEM;
1104 }
1105
1106 memcpy(key->key, newkey, newkeylen);
1107 key->keylen = newkeylen;
1108 key->family = family;
1109 key->prefixlen = prefixlen;
1110 memcpy(&key->addr, addr,
1111 (family == AF_INET6) ? sizeof(struct in6_addr) :
1112 sizeof(struct in_addr));
1113 hlist_add_head_rcu(&key->node, &md5sig->head);
1114 return 0;
1115}
1116EXPORT_SYMBOL(tcp_md5_do_add);
1117
1118int tcp_md5_do_del(struct sock *sk, const union tcp_md5_addr *addr, int family,
1119 u8 prefixlen)
1120{
1121 struct tcp_md5sig_key *key;
1122
1123 key = tcp_md5_do_lookup_exact(sk, addr, family, prefixlen);
1124 if (!key)
1125 return -ENOENT;
1126 hlist_del_rcu(&key->node);
1127 atomic_sub(sizeof(*key), &sk->sk_omem_alloc);
1128 kfree_rcu(key, rcu);
1129 return 0;
1130}
1131EXPORT_SYMBOL(tcp_md5_do_del);
1132
1133static void tcp_clear_md5_list(struct sock *sk)
1134{
1135 struct tcp_sock *tp = tcp_sk(sk);
1136 struct tcp_md5sig_key *key;
1137 struct hlist_node *n;
1138 struct tcp_md5sig_info *md5sig;
1139
1140 md5sig = rcu_dereference_protected(tp->md5sig_info, 1);
1141
1142 hlist_for_each_entry_safe(key, n, &md5sig->head, node) {
1143 hlist_del_rcu(&key->node);
1144 atomic_sub(sizeof(*key), &sk->sk_omem_alloc);
1145 kfree_rcu(key, rcu);
1146 }
1147}
1148
1149static int tcp_v4_parse_md5_keys(struct sock *sk, int optname,
1150 char __user *optval, int optlen)
1151{
1152 struct tcp_md5sig cmd;
1153 struct sockaddr_in *sin = (struct sockaddr_in *)&cmd.tcpm_addr;
1154 u8 prefixlen = 32;
1155
1156 if (optlen < sizeof(cmd))
1157 return -EINVAL;
1158
1159 if (copy_from_user(&cmd, optval, sizeof(cmd)))
1160 return -EFAULT;
1161
1162 if (sin->sin_family != AF_INET)
1163 return -EINVAL;
1164
1165 if (optname == TCP_MD5SIG_EXT &&
1166 cmd.tcpm_flags & TCP_MD5SIG_FLAG_PREFIX) {
1167 prefixlen = cmd.tcpm_prefixlen;
1168 if (prefixlen > 32)
1169 return -EINVAL;
1170 }
1171
1172 if (!cmd.tcpm_keylen)
1173 return tcp_md5_do_del(sk, (union tcp_md5_addr *)&sin->sin_addr.s_addr,
1174 AF_INET, prefixlen);
1175
1176 if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN)
1177 return -EINVAL;
1178
1179 return tcp_md5_do_add(sk, (union tcp_md5_addr *)&sin->sin_addr.s_addr,
1180 AF_INET, prefixlen, cmd.tcpm_key, cmd.tcpm_keylen,
1181 GFP_KERNEL);
1182}
1183
1184static int tcp_v4_md5_hash_headers(struct tcp_md5sig_pool *hp,
1185 __be32 daddr, __be32 saddr,
1186 const struct tcphdr *th, int nbytes)
1187{
1188 struct tcp4_pseudohdr *bp;
1189 struct scatterlist sg;
1190 struct tcphdr *_th;
1191
1192 bp = hp->scratch;
1193 bp->saddr = saddr;
1194 bp->daddr = daddr;
1195 bp->pad = 0;
1196 bp->protocol = IPPROTO_TCP;
1197 bp->len = cpu_to_be16(nbytes);
1198
1199 _th = (struct tcphdr *)(bp + 1);
1200 memcpy(_th, th, sizeof(*th));
1201 _th->check = 0;
1202
1203 sg_init_one(&sg, bp, sizeof(*bp) + sizeof(*th));
1204 ahash_request_set_crypt(hp->md5_req, &sg, NULL,
1205 sizeof(*bp) + sizeof(*th));
1206 return crypto_ahash_update(hp->md5_req);
1207}
1208
1209static int tcp_v4_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key,
1210 __be32 daddr, __be32 saddr, const struct tcphdr *th)
1211{
1212 struct tcp_md5sig_pool *hp;
1213 struct ahash_request *req;
1214
1215 hp = tcp_get_md5sig_pool();
1216 if (!hp)
1217 goto clear_hash_noput;
1218 req = hp->md5_req;
1219
1220 if (crypto_ahash_init(req))
1221 goto clear_hash;
1222 if (tcp_v4_md5_hash_headers(hp, daddr, saddr, th, th->doff << 2))
1223 goto clear_hash;
1224 if (tcp_md5_hash_key(hp, key))
1225 goto clear_hash;
1226 ahash_request_set_crypt(req, NULL, md5_hash, 0);
1227 if (crypto_ahash_final(req))
1228 goto clear_hash;
1229
1230 tcp_put_md5sig_pool();
1231 return 0;
1232
1233clear_hash:
1234 tcp_put_md5sig_pool();
1235clear_hash_noput:
1236 memset(md5_hash, 0, 16);
1237 return 1;
1238}
1239
1240int tcp_v4_md5_hash_skb(char *md5_hash, const struct tcp_md5sig_key *key,
1241 const struct sock *sk,
1242 const struct sk_buff *skb)
1243{
1244 struct tcp_md5sig_pool *hp;
1245 struct ahash_request *req;
1246 const struct tcphdr *th = tcp_hdr(skb);
1247 __be32 saddr, daddr;
1248
1249 if (sk) { /* valid for establish/request sockets */
1250 saddr = sk->sk_rcv_saddr;
1251 daddr = sk->sk_daddr;
1252 } else {
1253 const struct iphdr *iph = ip_hdr(skb);
1254 saddr = iph->saddr;
1255 daddr = iph->daddr;
1256 }
1257
1258 hp = tcp_get_md5sig_pool();
1259 if (!hp)
1260 goto clear_hash_noput;
1261 req = hp->md5_req;
1262
1263 if (crypto_ahash_init(req))
1264 goto clear_hash;
1265
1266 if (tcp_v4_md5_hash_headers(hp, daddr, saddr, th, skb->len))
1267 goto clear_hash;
1268 if (tcp_md5_hash_skb_data(hp, skb, th->doff << 2))
1269 goto clear_hash;
1270 if (tcp_md5_hash_key(hp, key))
1271 goto clear_hash;
1272 ahash_request_set_crypt(req, NULL, md5_hash, 0);
1273 if (crypto_ahash_final(req))
1274 goto clear_hash;
1275
1276 tcp_put_md5sig_pool();
1277 return 0;
1278
1279clear_hash:
1280 tcp_put_md5sig_pool();
1281clear_hash_noput:
1282 memset(md5_hash, 0, 16);
1283 return 1;
1284}
1285EXPORT_SYMBOL(tcp_v4_md5_hash_skb);
1286
1287#endif
1288
1289/* Called with rcu_read_lock() */
1290static bool tcp_v4_inbound_md5_hash(const struct sock *sk,
1291 const struct sk_buff *skb)
1292{
1293#ifdef CONFIG_TCP_MD5SIG
1294 /*
1295 * This gets called for each TCP segment that arrives
1296 * so we want to be efficient.
1297 * We have 3 drop cases:
1298 * o No MD5 hash and one expected.
1299 * o MD5 hash and we're not expecting one.
1300 * o MD5 hash and its wrong.
1301 */
1302 const __u8 *hash_location = NULL;
1303 struct tcp_md5sig_key *hash_expected;
1304 const struct iphdr *iph = ip_hdr(skb);
1305 const struct tcphdr *th = tcp_hdr(skb);
1306 int genhash;
1307 unsigned char newhash[16];
1308
1309 hash_expected = tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&iph->saddr,
1310 AF_INET);
1311 hash_location = tcp_parse_md5sig_option(th);
1312
1313 /* We've parsed the options - do we have a hash? */
1314 if (!hash_expected && !hash_location)
1315 return false;
1316
1317 if (hash_expected && !hash_location) {
1318 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5NOTFOUND);
1319 return true;
1320 }
1321
1322 if (!hash_expected && hash_location) {
1323 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5UNEXPECTED);
1324 return true;
1325 }
1326
1327 /* Okay, so this is hash_expected and hash_location -
1328 * so we need to calculate the checksum.
1329 */
1330 genhash = tcp_v4_md5_hash_skb(newhash,
1331 hash_expected,
1332 NULL, skb);
1333
1334 if (genhash || memcmp(hash_location, newhash, 16) != 0) {
1335 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5FAILURE);
1336 net_info_ratelimited("MD5 Hash failed for (%pI4, %d)->(%pI4, %d)%s\n",
1337 &iph->saddr, ntohs(th->source),
1338 &iph->daddr, ntohs(th->dest),
1339 genhash ? " tcp_v4_calc_md5_hash failed"
1340 : "");
1341 return true;
1342 }
1343 return false;
1344#endif
1345 return false;
1346}
1347
1348static void tcp_v4_init_req(struct request_sock *req,
1349 const struct sock *sk_listener,
1350 struct sk_buff *skb)
1351{
1352 struct inet_request_sock *ireq = inet_rsk(req);
1353 struct net *net = sock_net(sk_listener);
1354
1355 sk_rcv_saddr_set(req_to_sk(req), ip_hdr(skb)->daddr);
1356 sk_daddr_set(req_to_sk(req), ip_hdr(skb)->saddr);
1357 RCU_INIT_POINTER(ireq->ireq_opt, tcp_v4_save_options(net, skb));
1358}
1359
1360static struct dst_entry *tcp_v4_route_req(const struct sock *sk,
1361 struct flowi *fl,
1362 const struct request_sock *req)
1363{
1364 return inet_csk_route_req(sk, &fl->u.ip4, req);
1365}
1366
1367struct request_sock_ops tcp_request_sock_ops __read_mostly = {
1368 .family = PF_INET,
1369 .obj_size = sizeof(struct tcp_request_sock),
1370 .rtx_syn_ack = tcp_rtx_synack,
1371 .send_ack = tcp_v4_reqsk_send_ack,
1372 .destructor = tcp_v4_reqsk_destructor,
1373 .send_reset = tcp_v4_send_reset,
1374 .syn_ack_timeout = tcp_syn_ack_timeout,
1375};
1376
1377static const struct tcp_request_sock_ops tcp_request_sock_ipv4_ops = {
1378 .mss_clamp = TCP_MSS_DEFAULT,
1379#ifdef CONFIG_TCP_MD5SIG
1380 .req_md5_lookup = tcp_v4_md5_lookup,
1381 .calc_md5_hash = tcp_v4_md5_hash_skb,
1382#endif
1383 .init_req = tcp_v4_init_req,
1384#ifdef CONFIG_SYN_COOKIES
1385 .cookie_init_seq = cookie_v4_init_sequence,
1386#endif
1387 .route_req = tcp_v4_route_req,
1388 .init_seq = tcp_v4_init_seq,
1389 .init_ts_off = tcp_v4_init_ts_off,
1390 .send_synack = tcp_v4_send_synack,
1391};
1392
1393int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
1394{
1395 /* Never answer to SYNs send to broadcast or multicast */
1396 if (skb_rtable(skb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
1397 goto drop;
1398
1399 return tcp_conn_request(&tcp_request_sock_ops,
1400 &tcp_request_sock_ipv4_ops, sk, skb);
1401
1402drop:
1403 tcp_listendrop(sk);
1404 return 0;
1405}
1406EXPORT_SYMBOL(tcp_v4_conn_request);
1407
1408
1409/*
1410 * The three way handshake has completed - we got a valid synack -
1411 * now create the new socket.
1412 */
1413struct sock *tcp_v4_syn_recv_sock(const struct sock *sk, struct sk_buff *skb,
1414 struct request_sock *req,
1415 struct dst_entry *dst,
1416 struct request_sock *req_unhash,
1417 bool *own_req)
1418{
1419 struct inet_request_sock *ireq;
1420 struct inet_sock *newinet;
1421 struct tcp_sock *newtp;
1422 struct sock *newsk;
1423#ifdef CONFIG_TCP_MD5SIG
1424 struct tcp_md5sig_key *key;
1425#endif
1426 struct ip_options_rcu *inet_opt;
1427
1428 if (sk_acceptq_is_full(sk))
1429 goto exit_overflow;
1430
1431 newsk = tcp_create_openreq_child(sk, req, skb);
1432 if (!newsk)
1433 goto exit_nonewsk;
1434
1435 newsk->sk_gso_type = SKB_GSO_TCPV4;
1436 inet_sk_rx_dst_set(newsk, skb);
1437
1438 newtp = tcp_sk(newsk);
1439 newinet = inet_sk(newsk);
1440 ireq = inet_rsk(req);
1441 sk_daddr_set(newsk, ireq->ir_rmt_addr);
1442 sk_rcv_saddr_set(newsk, ireq->ir_loc_addr);
1443 newsk->sk_bound_dev_if = ireq->ir_iif;
1444 newinet->inet_saddr = ireq->ir_loc_addr;
1445 inet_opt = rcu_dereference(ireq->ireq_opt);
1446 RCU_INIT_POINTER(newinet->inet_opt, inet_opt);
1447 newinet->mc_index = inet_iif(skb);
1448 newinet->mc_ttl = ip_hdr(skb)->ttl;
1449 newinet->rcv_tos = ip_hdr(skb)->tos;
1450 inet_csk(newsk)->icsk_ext_hdr_len = 0;
1451 if (inet_opt)
1452 inet_csk(newsk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
1453 newinet->inet_id = prandom_u32();
1454
1455 if (!dst) {
1456 dst = inet_csk_route_child_sock(sk, newsk, req);
1457 if (!dst)
1458 goto put_and_exit;
1459 } else {
1460 /* syncookie case : see end of cookie_v4_check() */
1461 }
1462 sk_setup_caps(newsk, dst);
1463
1464 tcp_ca_openreq_child(newsk, dst);
1465
1466 tcp_sync_mss(newsk, dst_mtu(dst));
1467 newtp->advmss = tcp_mss_clamp(tcp_sk(sk), dst_metric_advmss(dst));
1468
1469 tcp_initialize_rcv_mss(newsk);
1470
1471#ifdef CONFIG_TCP_MD5SIG
1472 /* Copy over the MD5 key from the original socket */
1473 key = tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&newinet->inet_daddr,
1474 AF_INET);
1475 if (key) {
1476 /*
1477 * We're using one, so create a matching key
1478 * on the newsk structure. If we fail to get
1479 * memory, then we end up not copying the key
1480 * across. Shucks.
1481 */
1482 tcp_md5_do_add(newsk, (union tcp_md5_addr *)&newinet->inet_daddr,
1483 AF_INET, 32, key->key, key->keylen, GFP_ATOMIC);
1484 sk_nocaps_add(newsk, NETIF_F_GSO_MASK);
1485 }
1486#endif
1487
1488 if (__inet_inherit_port(sk, newsk) < 0)
1489 goto put_and_exit;
1490 *own_req = inet_ehash_nolisten(newsk, req_to_sk(req_unhash));
1491 if (likely(*own_req)) {
1492 tcp_move_syn(newtp, req);
1493 ireq->ireq_opt = NULL;
1494 } else {
1495 newinet->inet_opt = NULL;
1496 }
1497 return newsk;
1498
1499exit_overflow:
1500 NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
1501exit_nonewsk:
1502 dst_release(dst);
1503exit:
1504 tcp_listendrop(sk);
1505 return NULL;
1506put_and_exit:
1507 newinet->inet_opt = NULL;
1508 inet_csk_prepare_forced_close(newsk);
1509 tcp_done(newsk);
1510 goto exit;
1511}
1512EXPORT_SYMBOL(tcp_v4_syn_recv_sock);
1513
1514static struct sock *tcp_v4_cookie_check(struct sock *sk, struct sk_buff *skb)
1515{
1516#ifdef CONFIG_SYN_COOKIES
1517 const struct tcphdr *th = tcp_hdr(skb);
1518
1519 if (!th->syn)
1520 sk = cookie_v4_check(sk, skb);
1521#endif
1522 return sk;
1523}
1524
1525u16 tcp_v4_get_syncookie(struct sock *sk, struct iphdr *iph,
1526 struct tcphdr *th, u32 *cookie)
1527{
1528 u16 mss = 0;
1529#ifdef CONFIG_SYN_COOKIES
1530 mss = tcp_get_syncookie_mss(&tcp_request_sock_ops,
1531 &tcp_request_sock_ipv4_ops, sk, th);
1532 if (mss) {
1533 *cookie = __cookie_v4_init_sequence(iph, th, &mss);
1534 tcp_synq_overflow(sk);
1535 }
1536#endif
1537 return mss;
1538}
1539
1540/* The socket must have it's spinlock held when we get
1541 * here, unless it is a TCP_LISTEN socket.
1542 *
1543 * We have a potential double-lock case here, so even when
1544 * doing backlog processing we use the BH locking scheme.
1545 * This is because we cannot sleep with the original spinlock
1546 * held.
1547 */
1548int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
1549{
1550 struct sock *rsk;
1551
1552 if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
1553 struct dst_entry *dst = sk->sk_rx_dst;
1554
1555 sock_rps_save_rxhash(sk, skb);
1556 sk_mark_napi_id(sk, skb);
1557 if (dst) {
1558 if (inet_sk(sk)->rx_dst_ifindex != skb->skb_iif ||
1559 !dst->ops->check(dst, 0)) {
1560 dst_release(dst);
1561 sk->sk_rx_dst = NULL;
1562 }
1563 }
1564 tcp_rcv_established(sk, skb);
1565 return 0;
1566 }
1567
1568 if (tcp_checksum_complete(skb))
1569 goto csum_err;
1570
1571 if (sk->sk_state == TCP_LISTEN) {
1572 struct sock *nsk = tcp_v4_cookie_check(sk, skb);
1573
1574 if (!nsk)
1575 goto discard;
1576 if (nsk != sk) {
1577 if (tcp_child_process(sk, nsk, skb)) {
1578 rsk = nsk;
1579 goto reset;
1580 }
1581 return 0;
1582 }
1583 } else
1584 sock_rps_save_rxhash(sk, skb);
1585
1586 if (tcp_rcv_state_process(sk, skb)) {
1587 rsk = sk;
1588 goto reset;
1589 }
1590 return 0;
1591
1592reset:
1593 tcp_v4_send_reset(rsk, skb);
1594discard:
1595 kfree_skb(skb);
1596 /* Be careful here. If this function gets more complicated and
1597 * gcc suffers from register pressure on the x86, sk (in %ebx)
1598 * might be destroyed here. This current version compiles correctly,
1599 * but you have been warned.
1600 */
1601 return 0;
1602
1603csum_err:
1604 TCP_INC_STATS(sock_net(sk), TCP_MIB_CSUMERRORS);
1605 TCP_INC_STATS(sock_net(sk), TCP_MIB_INERRS);
1606 goto discard;
1607}
1608EXPORT_SYMBOL(tcp_v4_do_rcv);
1609
1610int tcp_v4_early_demux(struct sk_buff *skb)
1611{
1612 const struct iphdr *iph;
1613 const struct tcphdr *th;
1614 struct sock *sk;
1615
1616 if (skb->pkt_type != PACKET_HOST)
1617 return 0;
1618
1619 if (!pskb_may_pull(skb, skb_transport_offset(skb) + sizeof(struct tcphdr)))
1620 return 0;
1621
1622 iph = ip_hdr(skb);
1623 th = tcp_hdr(skb);
1624
1625 if (th->doff < sizeof(struct tcphdr) / 4)
1626 return 0;
1627
1628 sk = __inet_lookup_established(dev_net(skb->dev), &tcp_hashinfo,
1629 iph->saddr, th->source,
1630 iph->daddr, ntohs(th->dest),
1631 skb->skb_iif, inet_sdif(skb));
1632 if (sk) {
1633 skb->sk = sk;
1634 skb->destructor = sock_edemux;
1635 if (sk_fullsock(sk)) {
1636 struct dst_entry *dst = READ_ONCE(sk->sk_rx_dst);
1637
1638 if (dst)
1639 dst = dst_check(dst, 0);
1640 if (dst &&
1641 inet_sk(sk)->rx_dst_ifindex == skb->skb_iif)
1642 skb_dst_set_noref(skb, dst);
1643 }
1644 }
1645 return 0;
1646}
1647
1648bool tcp_add_backlog(struct sock *sk, struct sk_buff *skb)
1649{
1650 u32 limit = READ_ONCE(sk->sk_rcvbuf) + READ_ONCE(sk->sk_sndbuf);
1651 struct skb_shared_info *shinfo;
1652 const struct tcphdr *th;
1653 struct tcphdr *thtail;
1654 struct sk_buff *tail;
1655 unsigned int hdrlen;
1656 bool fragstolen;
1657 u32 gso_segs;
1658 int delta;
1659
1660 /* In case all data was pulled from skb frags (in __pskb_pull_tail()),
1661 * we can fix skb->truesize to its real value to avoid future drops.
1662 * This is valid because skb is not yet charged to the socket.
1663 * It has been noticed pure SACK packets were sometimes dropped
1664 * (if cooked by drivers without copybreak feature).
1665 */
1666 skb_condense(skb);
1667
1668 skb_dst_drop(skb);
1669
1670 if (unlikely(tcp_checksum_complete(skb))) {
1671 bh_unlock_sock(sk);
1672 __TCP_INC_STATS(sock_net(sk), TCP_MIB_CSUMERRORS);
1673 __TCP_INC_STATS(sock_net(sk), TCP_MIB_INERRS);
1674 return true;
1675 }
1676
1677 /* Attempt coalescing to last skb in backlog, even if we are
1678 * above the limits.
1679 * This is okay because skb capacity is limited to MAX_SKB_FRAGS.
1680 */
1681 th = (const struct tcphdr *)skb->data;
1682 hdrlen = th->doff * 4;
1683 shinfo = skb_shinfo(skb);
1684
1685 if (!shinfo->gso_size)
1686 shinfo->gso_size = skb->len - hdrlen;
1687
1688 if (!shinfo->gso_segs)
1689 shinfo->gso_segs = 1;
1690
1691 tail = sk->sk_backlog.tail;
1692 if (!tail)
1693 goto no_coalesce;
1694 thtail = (struct tcphdr *)tail->data;
1695
1696 if (TCP_SKB_CB(tail)->end_seq != TCP_SKB_CB(skb)->seq ||
1697 TCP_SKB_CB(tail)->ip_dsfield != TCP_SKB_CB(skb)->ip_dsfield ||
1698 ((TCP_SKB_CB(tail)->tcp_flags |
1699 TCP_SKB_CB(skb)->tcp_flags) & (TCPHDR_SYN | TCPHDR_RST | TCPHDR_URG)) ||
1700 !((TCP_SKB_CB(tail)->tcp_flags &
1701 TCP_SKB_CB(skb)->tcp_flags) & TCPHDR_ACK) ||
1702 ((TCP_SKB_CB(tail)->tcp_flags ^
1703 TCP_SKB_CB(skb)->tcp_flags) & (TCPHDR_ECE | TCPHDR_CWR)) ||
1704#ifdef CONFIG_TLS_DEVICE
1705 tail->decrypted != skb->decrypted ||
1706#endif
1707 thtail->doff != th->doff ||
1708 memcmp(thtail + 1, th + 1, hdrlen - sizeof(*th)))
1709 goto no_coalesce;
1710
1711 __skb_pull(skb, hdrlen);
1712 if (skb_try_coalesce(tail, skb, &fragstolen, &delta)) {
1713 thtail->window = th->window;
1714
1715 TCP_SKB_CB(tail)->end_seq = TCP_SKB_CB(skb)->end_seq;
1716
1717 if (after(TCP_SKB_CB(skb)->ack_seq, TCP_SKB_CB(tail)->ack_seq))
1718 TCP_SKB_CB(tail)->ack_seq = TCP_SKB_CB(skb)->ack_seq;
1719
1720 /* We have to update both TCP_SKB_CB(tail)->tcp_flags and
1721 * thtail->fin, so that the fast path in tcp_rcv_established()
1722 * is not entered if we append a packet with a FIN.
1723 * SYN, RST, URG are not present.
1724 * ACK is set on both packets.
1725 * PSH : we do not really care in TCP stack,
1726 * at least for 'GRO' packets.
1727 */
1728 thtail->fin |= th->fin;
1729 TCP_SKB_CB(tail)->tcp_flags |= TCP_SKB_CB(skb)->tcp_flags;
1730
1731 if (TCP_SKB_CB(skb)->has_rxtstamp) {
1732 TCP_SKB_CB(tail)->has_rxtstamp = true;
1733 tail->tstamp = skb->tstamp;
1734 skb_hwtstamps(tail)->hwtstamp = skb_hwtstamps(skb)->hwtstamp;
1735 }
1736
1737 /* Not as strict as GRO. We only need to carry mss max value */
1738 skb_shinfo(tail)->gso_size = max(shinfo->gso_size,
1739 skb_shinfo(tail)->gso_size);
1740
1741 gso_segs = skb_shinfo(tail)->gso_segs + shinfo->gso_segs;
1742 skb_shinfo(tail)->gso_segs = min_t(u32, gso_segs, 0xFFFF);
1743
1744 sk->sk_backlog.len += delta;
1745 __NET_INC_STATS(sock_net(sk),
1746 LINUX_MIB_TCPBACKLOGCOALESCE);
1747 kfree_skb_partial(skb, fragstolen);
1748 return false;
1749 }
1750 __skb_push(skb, hdrlen);
1751
1752no_coalesce:
1753 /* Only socket owner can try to collapse/prune rx queues
1754 * to reduce memory overhead, so add a little headroom here.
1755 * Few sockets backlog are possibly concurrently non empty.
1756 */
1757 limit += 64*1024;
1758
1759 if (unlikely(sk_add_backlog(sk, skb, limit))) {
1760 bh_unlock_sock(sk);
1761 __NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPBACKLOGDROP);
1762 return true;
1763 }
1764 return false;
1765}
1766EXPORT_SYMBOL(tcp_add_backlog);
1767
1768int tcp_filter(struct sock *sk, struct sk_buff *skb)
1769{
1770 struct tcphdr *th = (struct tcphdr *)skb->data;
1771
1772 return sk_filter_trim_cap(sk, skb, th->doff * 4);
1773}
1774EXPORT_SYMBOL(tcp_filter);
1775
1776static void tcp_v4_restore_cb(struct sk_buff *skb)
1777{
1778 memmove(IPCB(skb), &TCP_SKB_CB(skb)->header.h4,
1779 sizeof(struct inet_skb_parm));
1780}
1781
1782static void tcp_v4_fill_cb(struct sk_buff *skb, const struct iphdr *iph,
1783 const struct tcphdr *th)
1784{
1785 /* This is tricky : We move IPCB at its correct location into TCP_SKB_CB()
1786 * barrier() makes sure compiler wont play fool^Waliasing games.
1787 */
1788 memmove(&TCP_SKB_CB(skb)->header.h4, IPCB(skb),
1789 sizeof(struct inet_skb_parm));
1790 barrier();
1791
1792 TCP_SKB_CB(skb)->seq = ntohl(th->seq);
1793 TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
1794 skb->len - th->doff * 4);
1795 TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
1796 TCP_SKB_CB(skb)->tcp_flags = tcp_flag_byte(th);
1797 TCP_SKB_CB(skb)->tcp_tw_isn = 0;
1798 TCP_SKB_CB(skb)->ip_dsfield = ipv4_get_dsfield(iph);
1799 TCP_SKB_CB(skb)->sacked = 0;
1800 TCP_SKB_CB(skb)->has_rxtstamp =
1801 skb->tstamp || skb_hwtstamps(skb)->hwtstamp;
1802}
1803
1804/*
1805 * From tcp_input.c
1806 */
1807
1808int tcp_v4_rcv(struct sk_buff *skb)
1809{
1810 struct net *net = dev_net(skb->dev);
1811 struct sk_buff *skb_to_free;
1812 int sdif = inet_sdif(skb);
1813 const struct iphdr *iph;
1814 const struct tcphdr *th;
1815 bool refcounted;
1816 struct sock *sk;
1817 int ret;
1818
1819 if (skb->pkt_type != PACKET_HOST)
1820 goto discard_it;
1821
1822 /* Count it even if it's bad */
1823 __TCP_INC_STATS(net, TCP_MIB_INSEGS);
1824
1825 if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
1826 goto discard_it;
1827
1828 th = (const struct tcphdr *)skb->data;
1829
1830 if (unlikely(th->doff < sizeof(struct tcphdr) / 4))
1831 goto bad_packet;
1832 if (!pskb_may_pull(skb, th->doff * 4))
1833 goto discard_it;
1834
1835 /* An explanation is required here, I think.
1836 * Packet length and doff are validated by header prediction,
1837 * provided case of th->doff==0 is eliminated.
1838 * So, we defer the checks. */
1839
1840 if (skb_checksum_init(skb, IPPROTO_TCP, inet_compute_pseudo))
1841 goto csum_error;
1842
1843 th = (const struct tcphdr *)skb->data;
1844 iph = ip_hdr(skb);
1845lookup:
1846 sk = __inet_lookup_skb(&tcp_hashinfo, skb, __tcp_hdrlen(th), th->source,
1847 th->dest, sdif, &refcounted);
1848 if (!sk)
1849 goto no_tcp_socket;
1850
1851process:
1852 if (sk->sk_state == TCP_TIME_WAIT)
1853 goto do_time_wait;
1854
1855 if (sk->sk_state == TCP_NEW_SYN_RECV) {
1856 struct request_sock *req = inet_reqsk(sk);
1857 bool req_stolen = false;
1858 struct sock *nsk;
1859
1860 sk = req->rsk_listener;
1861 if (unlikely(tcp_v4_inbound_md5_hash(sk, skb))) {
1862 sk_drops_add(sk, skb);
1863 reqsk_put(req);
1864 goto discard_it;
1865 }
1866 if (tcp_checksum_complete(skb)) {
1867 reqsk_put(req);
1868 goto csum_error;
1869 }
1870 if (unlikely(sk->sk_state != TCP_LISTEN)) {
1871 inet_csk_reqsk_queue_drop_and_put(sk, req);
1872 goto lookup;
1873 }
1874 /* We own a reference on the listener, increase it again
1875 * as we might lose it too soon.
1876 */
1877 sock_hold(sk);
1878 refcounted = true;
1879 nsk = NULL;
1880 if (!tcp_filter(sk, skb)) {
1881 th = (const struct tcphdr *)skb->data;
1882 iph = ip_hdr(skb);
1883 tcp_v4_fill_cb(skb, iph, th);
1884 nsk = tcp_check_req(sk, skb, req, false, &req_stolen);
1885 }
1886 if (!nsk) {
1887 reqsk_put(req);
1888 if (req_stolen) {
1889 /* Another cpu got exclusive access to req
1890 * and created a full blown socket.
1891 * Try to feed this packet to this socket
1892 * instead of discarding it.
1893 */
1894 tcp_v4_restore_cb(skb);
1895 sock_put(sk);
1896 goto lookup;
1897 }
1898 goto discard_and_relse;
1899 }
1900 if (nsk == sk) {
1901 reqsk_put(req);
1902 tcp_v4_restore_cb(skb);
1903 } else if (tcp_child_process(sk, nsk, skb)) {
1904 tcp_v4_send_reset(nsk, skb);
1905 goto discard_and_relse;
1906 } else {
1907 sock_put(sk);
1908 return 0;
1909 }
1910 }
1911 if (unlikely(iph->ttl < inet_sk(sk)->min_ttl)) {
1912 __NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP);
1913 goto discard_and_relse;
1914 }
1915
1916 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
1917 goto discard_and_relse;
1918
1919 if (tcp_v4_inbound_md5_hash(sk, skb))
1920 goto discard_and_relse;
1921
1922 nf_reset_ct(skb);
1923
1924 if (tcp_filter(sk, skb))
1925 goto discard_and_relse;
1926 th = (const struct tcphdr *)skb->data;
1927 iph = ip_hdr(skb);
1928 tcp_v4_fill_cb(skb, iph, th);
1929
1930 skb->dev = NULL;
1931
1932 if (sk->sk_state == TCP_LISTEN) {
1933 ret = tcp_v4_do_rcv(sk, skb);
1934 goto put_and_return;
1935 }
1936
1937 sk_incoming_cpu_update(sk);
1938
1939 bh_lock_sock_nested(sk);
1940 tcp_segs_in(tcp_sk(sk), skb);
1941 ret = 0;
1942 if (!sock_owned_by_user(sk)) {
1943 skb_to_free = sk->sk_rx_skb_cache;
1944 sk->sk_rx_skb_cache = NULL;
1945 ret = tcp_v4_do_rcv(sk, skb);
1946 } else {
1947 if (tcp_add_backlog(sk, skb))
1948 goto discard_and_relse;
1949 skb_to_free = NULL;
1950 }
1951 bh_unlock_sock(sk);
1952 if (skb_to_free)
1953 __kfree_skb(skb_to_free);
1954
1955put_and_return:
1956 if (refcounted)
1957 sock_put(sk);
1958
1959 return ret;
1960
1961no_tcp_socket:
1962 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
1963 goto discard_it;
1964
1965 tcp_v4_fill_cb(skb, iph, th);
1966
1967 if (tcp_checksum_complete(skb)) {
1968csum_error:
1969 __TCP_INC_STATS(net, TCP_MIB_CSUMERRORS);
1970bad_packet:
1971 __TCP_INC_STATS(net, TCP_MIB_INERRS);
1972 } else {
1973 tcp_v4_send_reset(NULL, skb);
1974 }
1975
1976discard_it:
1977 /* Discard frame. */
1978 kfree_skb(skb);
1979 return 0;
1980
1981discard_and_relse:
1982 sk_drops_add(sk, skb);
1983 if (refcounted)
1984 sock_put(sk);
1985 goto discard_it;
1986
1987do_time_wait:
1988 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
1989 inet_twsk_put(inet_twsk(sk));
1990 goto discard_it;
1991 }
1992
1993 tcp_v4_fill_cb(skb, iph, th);
1994
1995 if (tcp_checksum_complete(skb)) {
1996 inet_twsk_put(inet_twsk(sk));
1997 goto csum_error;
1998 }
1999 switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) {
2000 case TCP_TW_SYN: {
2001 struct sock *sk2 = inet_lookup_listener(dev_net(skb->dev),
2002 &tcp_hashinfo, skb,
2003 __tcp_hdrlen(th),
2004 iph->saddr, th->source,
2005 iph->daddr, th->dest,
2006 inet_iif(skb),
2007 sdif);
2008 if (sk2) {
2009 inet_twsk_deschedule_put(inet_twsk(sk));
2010 sk = sk2;
2011 tcp_v4_restore_cb(skb);
2012 refcounted = false;
2013 goto process;
2014 }
2015 }
2016 /* to ACK */
2017 /* fall through */
2018 case TCP_TW_ACK:
2019 tcp_v4_timewait_ack(sk, skb);
2020 break;
2021 case TCP_TW_RST:
2022 tcp_v4_send_reset(sk, skb);
2023 inet_twsk_deschedule_put(inet_twsk(sk));
2024 goto discard_it;
2025 case TCP_TW_SUCCESS:;
2026 }
2027 goto discard_it;
2028}
2029
2030static struct timewait_sock_ops tcp_timewait_sock_ops = {
2031 .twsk_obj_size = sizeof(struct tcp_timewait_sock),
2032 .twsk_unique = tcp_twsk_unique,
2033 .twsk_destructor= tcp_twsk_destructor,
2034};
2035
2036void inet_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb)
2037{
2038 struct dst_entry *dst = skb_dst(skb);
2039
2040 if (dst && dst_hold_safe(dst)) {
2041 sk->sk_rx_dst = dst;
2042 inet_sk(sk)->rx_dst_ifindex = skb->skb_iif;
2043 }
2044}
2045EXPORT_SYMBOL(inet_sk_rx_dst_set);
2046
2047const struct inet_connection_sock_af_ops ipv4_specific = {
2048 .queue_xmit = ip_queue_xmit,
2049 .send_check = tcp_v4_send_check,
2050 .rebuild_header = inet_sk_rebuild_header,
2051 .sk_rx_dst_set = inet_sk_rx_dst_set,
2052 .conn_request = tcp_v4_conn_request,
2053 .syn_recv_sock = tcp_v4_syn_recv_sock,
2054 .net_header_len = sizeof(struct iphdr),
2055 .setsockopt = ip_setsockopt,
2056 .getsockopt = ip_getsockopt,
2057 .addr2sockaddr = inet_csk_addr2sockaddr,
2058 .sockaddr_len = sizeof(struct sockaddr_in),
2059#ifdef CONFIG_COMPAT
2060 .compat_setsockopt = compat_ip_setsockopt,
2061 .compat_getsockopt = compat_ip_getsockopt,
2062#endif
2063 .mtu_reduced = tcp_v4_mtu_reduced,
2064};
2065EXPORT_SYMBOL(ipv4_specific);
2066
2067#ifdef CONFIG_TCP_MD5SIG
2068static const struct tcp_sock_af_ops tcp_sock_ipv4_specific = {
2069 .md5_lookup = tcp_v4_md5_lookup,
2070 .calc_md5_hash = tcp_v4_md5_hash_skb,
2071 .md5_parse = tcp_v4_parse_md5_keys,
2072};
2073#endif
2074
2075/* NOTE: A lot of things set to zero explicitly by call to
2076 * sk_alloc() so need not be done here.
2077 */
2078static int tcp_v4_init_sock(struct sock *sk)
2079{
2080 struct inet_connection_sock *icsk = inet_csk(sk);
2081
2082 tcp_init_sock(sk);
2083
2084 icsk->icsk_af_ops = &ipv4_specific;
2085
2086#ifdef CONFIG_TCP_MD5SIG
2087 tcp_sk(sk)->af_specific = &tcp_sock_ipv4_specific;
2088#endif
2089
2090 return 0;
2091}
2092
2093void tcp_v4_destroy_sock(struct sock *sk)
2094{
2095 struct tcp_sock *tp = tcp_sk(sk);
2096
2097 trace_tcp_destroy_sock(sk);
2098
2099 tcp_clear_xmit_timers(sk);
2100
2101 tcp_cleanup_congestion_control(sk);
2102
2103 tcp_cleanup_ulp(sk);
2104
2105 /* Cleanup up the write buffer. */
2106 tcp_write_queue_purge(sk);
2107
2108 /* Check if we want to disable active TFO */
2109 tcp_fastopen_active_disable_ofo_check(sk);
2110
2111 /* Cleans up our, hopefully empty, out_of_order_queue. */
2112 skb_rbtree_purge(&tp->out_of_order_queue);
2113
2114#ifdef CONFIG_TCP_MD5SIG
2115 /* Clean up the MD5 key list, if any */
2116 if (tp->md5sig_info) {
2117 tcp_clear_md5_list(sk);
2118 kfree_rcu(rcu_dereference_protected(tp->md5sig_info, 1), rcu);
2119 tp->md5sig_info = NULL;
2120 }
2121#endif
2122
2123 /* Clean up a referenced TCP bind bucket. */
2124 if (inet_csk(sk)->icsk_bind_hash)
2125 inet_put_port(sk);
2126
2127 BUG_ON(rcu_access_pointer(tp->fastopen_rsk));
2128
2129 /* If socket is aborted during connect operation */
2130 tcp_free_fastopen_req(tp);
2131 tcp_fastopen_destroy_cipher(sk);
2132 tcp_saved_syn_free(tp);
2133
2134 sk_sockets_allocated_dec(sk);
2135}
2136EXPORT_SYMBOL(tcp_v4_destroy_sock);
2137
2138#ifdef CONFIG_PROC_FS
2139/* Proc filesystem TCP sock list dumping. */
2140
2141/*
2142 * Get next listener socket follow cur. If cur is NULL, get first socket
2143 * starting from bucket given in st->bucket; when st->bucket is zero the
2144 * very first socket in the hash table is returned.
2145 */
2146static void *listening_get_next(struct seq_file *seq, void *cur)
2147{
2148 struct tcp_seq_afinfo *afinfo = PDE_DATA(file_inode(seq->file));
2149 struct tcp_iter_state *st = seq->private;
2150 struct net *net = seq_file_net(seq);
2151 struct inet_listen_hashbucket *ilb;
2152 struct sock *sk = cur;
2153
2154 if (!sk) {
2155get_head:
2156 ilb = &tcp_hashinfo.listening_hash[st->bucket];
2157 spin_lock(&ilb->lock);
2158 sk = sk_head(&ilb->head);
2159 st->offset = 0;
2160 goto get_sk;
2161 }
2162 ilb = &tcp_hashinfo.listening_hash[st->bucket];
2163 ++st->num;
2164 ++st->offset;
2165
2166 sk = sk_next(sk);
2167get_sk:
2168 sk_for_each_from(sk) {
2169 if (!net_eq(sock_net(sk), net))
2170 continue;
2171 if (sk->sk_family == afinfo->family)
2172 return sk;
2173 }
2174 spin_unlock(&ilb->lock);
2175 st->offset = 0;
2176 if (++st->bucket < INET_LHTABLE_SIZE)
2177 goto get_head;
2178 return NULL;
2179}
2180
2181static void *listening_get_idx(struct seq_file *seq, loff_t *pos)
2182{
2183 struct tcp_iter_state *st = seq->private;
2184 void *rc;
2185
2186 st->bucket = 0;
2187 st->offset = 0;
2188 rc = listening_get_next(seq, NULL);
2189
2190 while (rc && *pos) {
2191 rc = listening_get_next(seq, rc);
2192 --*pos;
2193 }
2194 return rc;
2195}
2196
2197static inline bool empty_bucket(const struct tcp_iter_state *st)
2198{
2199 return hlist_nulls_empty(&tcp_hashinfo.ehash[st->bucket].chain);
2200}
2201
2202/*
2203 * Get first established socket starting from bucket given in st->bucket.
2204 * If st->bucket is zero, the very first socket in the hash is returned.
2205 */
2206static void *established_get_first(struct seq_file *seq)
2207{
2208 struct tcp_seq_afinfo *afinfo = PDE_DATA(file_inode(seq->file));
2209 struct tcp_iter_state *st = seq->private;
2210 struct net *net = seq_file_net(seq);
2211 void *rc = NULL;
2212
2213 st->offset = 0;
2214 for (; st->bucket <= tcp_hashinfo.ehash_mask; ++st->bucket) {
2215 struct sock *sk;
2216 struct hlist_nulls_node *node;
2217 spinlock_t *lock = inet_ehash_lockp(&tcp_hashinfo, st->bucket);
2218
2219 /* Lockless fast path for the common case of empty buckets */
2220 if (empty_bucket(st))
2221 continue;
2222
2223 spin_lock_bh(lock);
2224 sk_nulls_for_each(sk, node, &tcp_hashinfo.ehash[st->bucket].chain) {
2225 if (sk->sk_family != afinfo->family ||
2226 !net_eq(sock_net(sk), net)) {
2227 continue;
2228 }
2229 rc = sk;
2230 goto out;
2231 }
2232 spin_unlock_bh(lock);
2233 }
2234out:
2235 return rc;
2236}
2237
2238static void *established_get_next(struct seq_file *seq, void *cur)
2239{
2240 struct tcp_seq_afinfo *afinfo = PDE_DATA(file_inode(seq->file));
2241 struct sock *sk = cur;
2242 struct hlist_nulls_node *node;
2243 struct tcp_iter_state *st = seq->private;
2244 struct net *net = seq_file_net(seq);
2245
2246 ++st->num;
2247 ++st->offset;
2248
2249 sk = sk_nulls_next(sk);
2250
2251 sk_nulls_for_each_from(sk, node) {
2252 if (sk->sk_family == afinfo->family &&
2253 net_eq(sock_net(sk), net))
2254 return sk;
2255 }
2256
2257 spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
2258 ++st->bucket;
2259 return established_get_first(seq);
2260}
2261
2262static void *established_get_idx(struct seq_file *seq, loff_t pos)
2263{
2264 struct tcp_iter_state *st = seq->private;
2265 void *rc;
2266
2267 st->bucket = 0;
2268 rc = established_get_first(seq);
2269
2270 while (rc && pos) {
2271 rc = established_get_next(seq, rc);
2272 --pos;
2273 }
2274 return rc;
2275}
2276
2277static void *tcp_get_idx(struct seq_file *seq, loff_t pos)
2278{
2279 void *rc;
2280 struct tcp_iter_state *st = seq->private;
2281
2282 st->state = TCP_SEQ_STATE_LISTENING;
2283 rc = listening_get_idx(seq, &pos);
2284
2285 if (!rc) {
2286 st->state = TCP_SEQ_STATE_ESTABLISHED;
2287 rc = established_get_idx(seq, pos);
2288 }
2289
2290 return rc;
2291}
2292
2293static void *tcp_seek_last_pos(struct seq_file *seq)
2294{
2295 struct tcp_iter_state *st = seq->private;
2296 int offset = st->offset;
2297 int orig_num = st->num;
2298 void *rc = NULL;
2299
2300 switch (st->state) {
2301 case TCP_SEQ_STATE_LISTENING:
2302 if (st->bucket >= INET_LHTABLE_SIZE)
2303 break;
2304 st->state = TCP_SEQ_STATE_LISTENING;
2305 rc = listening_get_next(seq, NULL);
2306 while (offset-- && rc)
2307 rc = listening_get_next(seq, rc);
2308 if (rc)
2309 break;
2310 st->bucket = 0;
2311 st->state = TCP_SEQ_STATE_ESTABLISHED;
2312 /* Fallthrough */
2313 case TCP_SEQ_STATE_ESTABLISHED:
2314 if (st->bucket > tcp_hashinfo.ehash_mask)
2315 break;
2316 rc = established_get_first(seq);
2317 while (offset-- && rc)
2318 rc = established_get_next(seq, rc);
2319 }
2320
2321 st->num = orig_num;
2322
2323 return rc;
2324}
2325
2326void *tcp_seq_start(struct seq_file *seq, loff_t *pos)
2327{
2328 struct tcp_iter_state *st = seq->private;
2329 void *rc;
2330
2331 if (*pos && *pos == st->last_pos) {
2332 rc = tcp_seek_last_pos(seq);
2333 if (rc)
2334 goto out;
2335 }
2336
2337 st->state = TCP_SEQ_STATE_LISTENING;
2338 st->num = 0;
2339 st->bucket = 0;
2340 st->offset = 0;
2341 rc = *pos ? tcp_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
2342
2343out:
2344 st->last_pos = *pos;
2345 return rc;
2346}
2347EXPORT_SYMBOL(tcp_seq_start);
2348
2349void *tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2350{
2351 struct tcp_iter_state *st = seq->private;
2352 void *rc = NULL;
2353
2354 if (v == SEQ_START_TOKEN) {
2355 rc = tcp_get_idx(seq, 0);
2356 goto out;
2357 }
2358
2359 switch (st->state) {
2360 case TCP_SEQ_STATE_LISTENING:
2361 rc = listening_get_next(seq, v);
2362 if (!rc) {
2363 st->state = TCP_SEQ_STATE_ESTABLISHED;
2364 st->bucket = 0;
2365 st->offset = 0;
2366 rc = established_get_first(seq);
2367 }
2368 break;
2369 case TCP_SEQ_STATE_ESTABLISHED:
2370 rc = established_get_next(seq, v);
2371 break;
2372 }
2373out:
2374 ++*pos;
2375 st->last_pos = *pos;
2376 return rc;
2377}
2378EXPORT_SYMBOL(tcp_seq_next);
2379
2380void tcp_seq_stop(struct seq_file *seq, void *v)
2381{
2382 struct tcp_iter_state *st = seq->private;
2383
2384 switch (st->state) {
2385 case TCP_SEQ_STATE_LISTENING:
2386 if (v != SEQ_START_TOKEN)
2387 spin_unlock(&tcp_hashinfo.listening_hash[st->bucket].lock);
2388 break;
2389 case TCP_SEQ_STATE_ESTABLISHED:
2390 if (v)
2391 spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
2392 break;
2393 }
2394}
2395EXPORT_SYMBOL(tcp_seq_stop);
2396
2397static void get_openreq4(const struct request_sock *req,
2398 struct seq_file *f, int i)
2399{
2400 const struct inet_request_sock *ireq = inet_rsk(req);
2401 long delta = req->rsk_timer.expires - jiffies;
2402
2403 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2404 " %02X %08X:%08X %02X:%08lX %08X %5u %8d %u %d %pK",
2405 i,
2406 ireq->ir_loc_addr,
2407 ireq->ir_num,
2408 ireq->ir_rmt_addr,
2409 ntohs(ireq->ir_rmt_port),
2410 TCP_SYN_RECV,
2411 0, 0, /* could print option size, but that is af dependent. */
2412 1, /* timers active (only the expire timer) */
2413 jiffies_delta_to_clock_t(delta),
2414 req->num_timeout,
2415 from_kuid_munged(seq_user_ns(f),
2416 sock_i_uid(req->rsk_listener)),
2417 0, /* non standard timer */
2418 0, /* open_requests have no inode */
2419 0,
2420 req);
2421}
2422
2423static void get_tcp4_sock(struct sock *sk, struct seq_file *f, int i)
2424{
2425 int timer_active;
2426 unsigned long timer_expires;
2427 const struct tcp_sock *tp = tcp_sk(sk);
2428 const struct inet_connection_sock *icsk = inet_csk(sk);
2429 const struct inet_sock *inet = inet_sk(sk);
2430 const struct fastopen_queue *fastopenq = &icsk->icsk_accept_queue.fastopenq;
2431 __be32 dest = inet->inet_daddr;
2432 __be32 src = inet->inet_rcv_saddr;
2433 __u16 destp = ntohs(inet->inet_dport);
2434 __u16 srcp = ntohs(inet->inet_sport);
2435 int rx_queue;
2436 int state;
2437
2438 if (icsk->icsk_pending == ICSK_TIME_RETRANS ||
2439 icsk->icsk_pending == ICSK_TIME_REO_TIMEOUT ||
2440 icsk->icsk_pending == ICSK_TIME_LOSS_PROBE) {
2441 timer_active = 1;
2442 timer_expires = icsk->icsk_timeout;
2443 } else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
2444 timer_active = 4;
2445 timer_expires = icsk->icsk_timeout;
2446 } else if (timer_pending(&sk->sk_timer)) {
2447 timer_active = 2;
2448 timer_expires = sk->sk_timer.expires;
2449 } else {
2450 timer_active = 0;
2451 timer_expires = jiffies;
2452 }
2453
2454 state = inet_sk_state_load(sk);
2455 if (state == TCP_LISTEN)
2456 rx_queue = sk->sk_ack_backlog;
2457 else
2458 /* Because we don't lock the socket,
2459 * we might find a transient negative value.
2460 */
2461 rx_queue = max_t(int, READ_ONCE(tp->rcv_nxt) -
2462 READ_ONCE(tp->copied_seq), 0);
2463
2464 seq_printf(f, "%4d: %08X:%04X %08X:%04X %02X %08X:%08X %02X:%08lX "
2465 "%08X %5u %8d %lu %d %pK %lu %lu %u %u %d",
2466 i, src, srcp, dest, destp, state,
2467 READ_ONCE(tp->write_seq) - tp->snd_una,
2468 rx_queue,
2469 timer_active,
2470 jiffies_delta_to_clock_t(timer_expires - jiffies),
2471 icsk->icsk_retransmits,
2472 from_kuid_munged(seq_user_ns(f), sock_i_uid(sk)),
2473 icsk->icsk_probes_out,
2474 sock_i_ino(sk),
2475 refcount_read(&sk->sk_refcnt), sk,
2476 jiffies_to_clock_t(icsk->icsk_rto),
2477 jiffies_to_clock_t(icsk->icsk_ack.ato),
2478 (icsk->icsk_ack.quick << 1) | inet_csk_in_pingpong_mode(sk),
2479 tp->snd_cwnd,
2480 state == TCP_LISTEN ?
2481 fastopenq->max_qlen :
2482 (tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh));
2483}
2484
2485static void get_timewait4_sock(const struct inet_timewait_sock *tw,
2486 struct seq_file *f, int i)
2487{
2488 long delta = tw->tw_timer.expires - jiffies;
2489 __be32 dest, src;
2490 __u16 destp, srcp;
2491
2492 dest = tw->tw_daddr;
2493 src = tw->tw_rcv_saddr;
2494 destp = ntohs(tw->tw_dport);
2495 srcp = ntohs(tw->tw_sport);
2496
2497 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2498 " %02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK",
2499 i, src, srcp, dest, destp, tw->tw_substate, 0, 0,
2500 3, jiffies_delta_to_clock_t(delta), 0, 0, 0, 0,
2501 refcount_read(&tw->tw_refcnt), tw);
2502}
2503
2504#define TMPSZ 150
2505
2506static int tcp4_seq_show(struct seq_file *seq, void *v)
2507{
2508 struct tcp_iter_state *st;
2509 struct sock *sk = v;
2510
2511 seq_setwidth(seq, TMPSZ - 1);
2512 if (v == SEQ_START_TOKEN) {
2513 seq_puts(seq, " sl local_address rem_address st tx_queue "
2514 "rx_queue tr tm->when retrnsmt uid timeout "
2515 "inode");
2516 goto out;
2517 }
2518 st = seq->private;
2519
2520 if (sk->sk_state == TCP_TIME_WAIT)
2521 get_timewait4_sock(v, seq, st->num);
2522 else if (sk->sk_state == TCP_NEW_SYN_RECV)
2523 get_openreq4(v, seq, st->num);
2524 else
2525 get_tcp4_sock(v, seq, st->num);
2526out:
2527 seq_pad(seq, '\n');
2528 return 0;
2529}
2530
2531static const struct seq_operations tcp4_seq_ops = {
2532 .show = tcp4_seq_show,
2533 .start = tcp_seq_start,
2534 .next = tcp_seq_next,
2535 .stop = tcp_seq_stop,
2536};
2537
2538static struct tcp_seq_afinfo tcp4_seq_afinfo = {
2539 .family = AF_INET,
2540};
2541
2542static int __net_init tcp4_proc_init_net(struct net *net)
2543{
2544 if (!proc_create_net_data("tcp", 0444, net->proc_net, &tcp4_seq_ops,
2545 sizeof(struct tcp_iter_state), &tcp4_seq_afinfo))
2546 return -ENOMEM;
2547 return 0;
2548}
2549
2550static void __net_exit tcp4_proc_exit_net(struct net *net)
2551{
2552 remove_proc_entry("tcp", net->proc_net);
2553}
2554
2555static struct pernet_operations tcp4_net_ops = {
2556 .init = tcp4_proc_init_net,
2557 .exit = tcp4_proc_exit_net,
2558};
2559
2560int __init tcp4_proc_init(void)
2561{
2562 return register_pernet_subsys(&tcp4_net_ops);
2563}
2564
2565void tcp4_proc_exit(void)
2566{
2567 unregister_pernet_subsys(&tcp4_net_ops);
2568}
2569#endif /* CONFIG_PROC_FS */
2570
2571struct proto tcp_prot = {
2572 .name = "TCP",
2573 .owner = THIS_MODULE,
2574 .close = tcp_close,
2575 .pre_connect = tcp_v4_pre_connect,
2576 .connect = tcp_v4_connect,
2577 .disconnect = tcp_disconnect,
2578 .accept = inet_csk_accept,
2579 .ioctl = tcp_ioctl,
2580 .init = tcp_v4_init_sock,
2581 .destroy = tcp_v4_destroy_sock,
2582 .shutdown = tcp_shutdown,
2583 .setsockopt = tcp_setsockopt,
2584 .getsockopt = tcp_getsockopt,
2585 .keepalive = tcp_set_keepalive,
2586 .recvmsg = tcp_recvmsg,
2587 .sendmsg = tcp_sendmsg,
2588 .sendpage = tcp_sendpage,
2589 .backlog_rcv = tcp_v4_do_rcv,
2590 .release_cb = tcp_release_cb,
2591 .hash = inet_hash,
2592 .unhash = inet_unhash,
2593 .get_port = inet_csk_get_port,
2594 .enter_memory_pressure = tcp_enter_memory_pressure,
2595 .leave_memory_pressure = tcp_leave_memory_pressure,
2596 .stream_memory_free = tcp_stream_memory_free,
2597 .sockets_allocated = &tcp_sockets_allocated,
2598 .orphan_count = &tcp_orphan_count,
2599 .memory_allocated = &tcp_memory_allocated,
2600 .memory_pressure = &tcp_memory_pressure,
2601 .sysctl_mem = sysctl_tcp_mem,
2602 .sysctl_wmem_offset = offsetof(struct net, ipv4.sysctl_tcp_wmem),
2603 .sysctl_rmem_offset = offsetof(struct net, ipv4.sysctl_tcp_rmem),
2604 .max_header = MAX_TCP_HEADER,
2605 .obj_size = sizeof(struct tcp_sock),
2606 .slab_flags = SLAB_TYPESAFE_BY_RCU,
2607 .twsk_prot = &tcp_timewait_sock_ops,
2608 .rsk_prot = &tcp_request_sock_ops,
2609 .h.hashinfo = &tcp_hashinfo,
2610 .no_autobind = true,
2611#ifdef CONFIG_COMPAT
2612 .compat_setsockopt = compat_tcp_setsockopt,
2613 .compat_getsockopt = compat_tcp_getsockopt,
2614#endif
2615 .diag_destroy = tcp_abort,
2616};
2617EXPORT_SYMBOL(tcp_prot);
2618
2619static void __net_exit tcp_sk_exit(struct net *net)
2620{
2621 int cpu;
2622
2623 if (net->ipv4.tcp_congestion_control)
2624 module_put(net->ipv4.tcp_congestion_control->owner);
2625
2626 for_each_possible_cpu(cpu)
2627 inet_ctl_sock_destroy(*per_cpu_ptr(net->ipv4.tcp_sk, cpu));
2628 free_percpu(net->ipv4.tcp_sk);
2629}
2630
2631static int __net_init tcp_sk_init(struct net *net)
2632{
2633 int res, cpu, cnt;
2634
2635 net->ipv4.tcp_sk = alloc_percpu(struct sock *);
2636 if (!net->ipv4.tcp_sk)
2637 return -ENOMEM;
2638
2639 for_each_possible_cpu(cpu) {
2640 struct sock *sk;
2641
2642 res = inet_ctl_sock_create(&sk, PF_INET, SOCK_RAW,
2643 IPPROTO_TCP, net);
2644 if (res)
2645 goto fail;
2646 sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
2647
2648 /* Please enforce IP_DF and IPID==0 for RST and
2649 * ACK sent in SYN-RECV and TIME-WAIT state.
2650 */
2651 inet_sk(sk)->pmtudisc = IP_PMTUDISC_DO;
2652
2653 *per_cpu_ptr(net->ipv4.tcp_sk, cpu) = sk;
2654 }
2655
2656 net->ipv4.sysctl_tcp_ecn = 2;
2657 net->ipv4.sysctl_tcp_ecn_fallback = 1;
2658
2659 net->ipv4.sysctl_tcp_base_mss = TCP_BASE_MSS;
2660 net->ipv4.sysctl_tcp_min_snd_mss = TCP_MIN_SND_MSS;
2661 net->ipv4.sysctl_tcp_probe_threshold = TCP_PROBE_THRESHOLD;
2662 net->ipv4.sysctl_tcp_probe_interval = TCP_PROBE_INTERVAL;
2663 net->ipv4.sysctl_tcp_mtu_probe_floor = TCP_MIN_SND_MSS;
2664
2665 net->ipv4.sysctl_tcp_keepalive_time = TCP_KEEPALIVE_TIME;
2666 net->ipv4.sysctl_tcp_keepalive_probes = TCP_KEEPALIVE_PROBES;
2667 net->ipv4.sysctl_tcp_keepalive_intvl = TCP_KEEPALIVE_INTVL;
2668
2669 net->ipv4.sysctl_tcp_syn_retries = TCP_SYN_RETRIES;
2670 net->ipv4.sysctl_tcp_synack_retries = TCP_SYNACK_RETRIES;
2671 net->ipv4.sysctl_tcp_syncookies = 1;
2672 net->ipv4.sysctl_tcp_reordering = TCP_FASTRETRANS_THRESH;
2673 net->ipv4.sysctl_tcp_retries1 = TCP_RETR1;
2674 net->ipv4.sysctl_tcp_retries2 = TCP_RETR2;
2675 net->ipv4.sysctl_tcp_orphan_retries = 0;
2676 net->ipv4.sysctl_tcp_fin_timeout = TCP_FIN_TIMEOUT;
2677 net->ipv4.sysctl_tcp_notsent_lowat = UINT_MAX;
2678 net->ipv4.sysctl_tcp_tw_reuse = 2;
2679
2680 cnt = tcp_hashinfo.ehash_mask + 1;
2681 net->ipv4.tcp_death_row.sysctl_max_tw_buckets = cnt / 2;
2682 net->ipv4.tcp_death_row.hashinfo = &tcp_hashinfo;
2683
2684 net->ipv4.sysctl_max_syn_backlog = max(128, cnt / 128);
2685 net->ipv4.sysctl_tcp_sack = 1;
2686 net->ipv4.sysctl_tcp_window_scaling = 1;
2687 net->ipv4.sysctl_tcp_timestamps = 1;
2688 net->ipv4.sysctl_tcp_early_retrans = 3;
2689 net->ipv4.sysctl_tcp_recovery = TCP_RACK_LOSS_DETECTION;
2690 net->ipv4.sysctl_tcp_slow_start_after_idle = 1; /* By default, RFC2861 behavior. */
2691 net->ipv4.sysctl_tcp_retrans_collapse = 1;
2692 net->ipv4.sysctl_tcp_max_reordering = 300;
2693 net->ipv4.sysctl_tcp_dsack = 1;
2694 net->ipv4.sysctl_tcp_app_win = 31;
2695 net->ipv4.sysctl_tcp_adv_win_scale = 1;
2696 net->ipv4.sysctl_tcp_frto = 2;
2697 net->ipv4.sysctl_tcp_moderate_rcvbuf = 1;
2698 /* This limits the percentage of the congestion window which we
2699 * will allow a single TSO frame to consume. Building TSO frames
2700 * which are too large can cause TCP streams to be bursty.
2701 */
2702 net->ipv4.sysctl_tcp_tso_win_divisor = 3;
2703 /* Default TSQ limit of 16 TSO segments */
2704 net->ipv4.sysctl_tcp_limit_output_bytes = 16 * 65536;
2705 /* rfc5961 challenge ack rate limiting */
2706 net->ipv4.sysctl_tcp_challenge_ack_limit = 1000;
2707 net->ipv4.sysctl_tcp_min_tso_segs = 2;
2708 net->ipv4.sysctl_tcp_min_rtt_wlen = 300;
2709 net->ipv4.sysctl_tcp_autocorking = 1;
2710 net->ipv4.sysctl_tcp_invalid_ratelimit = HZ/2;
2711 net->ipv4.sysctl_tcp_pacing_ss_ratio = 200;
2712 net->ipv4.sysctl_tcp_pacing_ca_ratio = 120;
2713 if (net != &init_net) {
2714 memcpy(net->ipv4.sysctl_tcp_rmem,
2715 init_net.ipv4.sysctl_tcp_rmem,
2716 sizeof(init_net.ipv4.sysctl_tcp_rmem));
2717 memcpy(net->ipv4.sysctl_tcp_wmem,
2718 init_net.ipv4.sysctl_tcp_wmem,
2719 sizeof(init_net.ipv4.sysctl_tcp_wmem));
2720 }
2721 net->ipv4.sysctl_tcp_comp_sack_delay_ns = NSEC_PER_MSEC;
2722 net->ipv4.sysctl_tcp_comp_sack_nr = 44;
2723 net->ipv4.sysctl_tcp_fastopen = TFO_CLIENT_ENABLE;
2724 spin_lock_init(&net->ipv4.tcp_fastopen_ctx_lock);
2725 net->ipv4.sysctl_tcp_fastopen_blackhole_timeout = 60 * 60;
2726 atomic_set(&net->ipv4.tfo_active_disable_times, 0);
2727
2728 /* Reno is always built in */
2729 if (!net_eq(net, &init_net) &&
2730 try_module_get(init_net.ipv4.tcp_congestion_control->owner))
2731 net->ipv4.tcp_congestion_control = init_net.ipv4.tcp_congestion_control;
2732 else
2733 net->ipv4.tcp_congestion_control = &tcp_reno;
2734
2735 return 0;
2736fail:
2737 tcp_sk_exit(net);
2738
2739 return res;
2740}
2741
2742static void __net_exit tcp_sk_exit_batch(struct list_head *net_exit_list)
2743{
2744 struct net *net;
2745
2746 inet_twsk_purge(&tcp_hashinfo, AF_INET);
2747
2748 list_for_each_entry(net, net_exit_list, exit_list)
2749 tcp_fastopen_ctx_destroy(net);
2750}
2751
2752static struct pernet_operations __net_initdata tcp_sk_ops = {
2753 .init = tcp_sk_init,
2754 .exit = tcp_sk_exit,
2755 .exit_batch = tcp_sk_exit_batch,
2756};
2757
2758void __init tcp_v4_init(void)
2759{
2760 if (register_pernet_subsys(&tcp_sk_ops))
2761 panic("Failed to create the TCP control socket.\n");
2762}