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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * INET An implementation of the TCP/IP protocol suite for the LINUX
4 * operating system. INET is implemented using the BSD Socket
5 * interface as the means of communication with the user level.
6 *
7 * Implementation of the Transmission Control Protocol(TCP).
8 *
9 * IPv4 specific functions
10 *
11 * code split from:
12 * linux/ipv4/tcp.c
13 * linux/ipv4/tcp_input.c
14 * linux/ipv4/tcp_output.c
15 *
16 * See tcp.c for author information
17 */
18
19/*
20 * Changes:
21 * David S. Miller : New socket lookup architecture.
22 * This code is dedicated to John Dyson.
23 * David S. Miller : Change semantics of established hash,
24 * half is devoted to TIME_WAIT sockets
25 * and the rest go in the other half.
26 * Andi Kleen : Add support for syncookies and fixed
27 * some bugs: ip options weren't passed to
28 * the TCP layer, missed a check for an
29 * ACK bit.
30 * Andi Kleen : Implemented fast path mtu discovery.
31 * Fixed many serious bugs in the
32 * request_sock handling and moved
33 * most of it into the af independent code.
34 * Added tail drop and some other bugfixes.
35 * Added new listen semantics.
36 * Mike McLagan : Routing by source
37 * Juan Jose Ciarlante: ip_dynaddr bits
38 * Andi Kleen: various fixes.
39 * Vitaly E. Lavrov : Transparent proxy revived after year
40 * coma.
41 * Andi Kleen : Fix new listen.
42 * Andi Kleen : Fix accept error reporting.
43 * YOSHIFUJI Hideaki @USAGI and: Support IPV6_V6ONLY socket option, which
44 * Alexey Kuznetsov allow both IPv4 and IPv6 sockets to bind
45 * a single port at the same time.
46 */
47
48#define pr_fmt(fmt) "TCP: " fmt
49
50#include <linux/bottom_half.h>
51#include <linux/types.h>
52#include <linux/fcntl.h>
53#include <linux/module.h>
54#include <linux/random.h>
55#include <linux/cache.h>
56#include <linux/jhash.h>
57#include <linux/init.h>
58#include <linux/times.h>
59#include <linux/slab.h>
60
61#include <net/net_namespace.h>
62#include <net/icmp.h>
63#include <net/inet_hashtables.h>
64#include <net/tcp.h>
65#include <net/transp_v6.h>
66#include <net/ipv6.h>
67#include <net/inet_common.h>
68#include <net/timewait_sock.h>
69#include <net/xfrm.h>
70#include <net/secure_seq.h>
71#include <net/busy_poll.h>
72
73#include <linux/inet.h>
74#include <linux/ipv6.h>
75#include <linux/stddef.h>
76#include <linux/proc_fs.h>
77#include <linux/seq_file.h>
78#include <linux/inetdevice.h>
79#include <linux/btf_ids.h>
80
81#include <crypto/hash.h>
82#include <linux/scatterlist.h>
83
84#include <trace/events/tcp.h>
85
86#ifdef CONFIG_TCP_MD5SIG
87static int tcp_v4_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key,
88 __be32 daddr, __be32 saddr, const struct tcphdr *th);
89#endif
90
91struct inet_hashinfo tcp_hashinfo;
92EXPORT_SYMBOL(tcp_hashinfo);
93
94static u32 tcp_v4_init_seq(const struct sk_buff *skb)
95{
96 return secure_tcp_seq(ip_hdr(skb)->daddr,
97 ip_hdr(skb)->saddr,
98 tcp_hdr(skb)->dest,
99 tcp_hdr(skb)->source);
100}
101
102static u32 tcp_v4_init_ts_off(const struct net *net, const struct sk_buff *skb)
103{
104 return secure_tcp_ts_off(net, ip_hdr(skb)->daddr, ip_hdr(skb)->saddr);
105}
106
107int tcp_twsk_unique(struct sock *sk, struct sock *sktw, void *twp)
108{
109 const struct inet_timewait_sock *tw = inet_twsk(sktw);
110 const struct tcp_timewait_sock *tcptw = tcp_twsk(sktw);
111 struct tcp_sock *tp = tcp_sk(sk);
112 int reuse = sock_net(sk)->ipv4.sysctl_tcp_tw_reuse;
113
114 if (reuse == 2) {
115 /* Still does not detect *everything* that goes through
116 * lo, since we require a loopback src or dst address
117 * or direct binding to 'lo' interface.
118 */
119 bool loopback = false;
120 if (tw->tw_bound_dev_if == LOOPBACK_IFINDEX)
121 loopback = true;
122#if IS_ENABLED(CONFIG_IPV6)
123 if (tw->tw_family == AF_INET6) {
124 if (ipv6_addr_loopback(&tw->tw_v6_daddr) ||
125 ipv6_addr_v4mapped_loopback(&tw->tw_v6_daddr) ||
126 ipv6_addr_loopback(&tw->tw_v6_rcv_saddr) ||
127 ipv6_addr_v4mapped_loopback(&tw->tw_v6_rcv_saddr))
128 loopback = true;
129 } else
130#endif
131 {
132 if (ipv4_is_loopback(tw->tw_daddr) ||
133 ipv4_is_loopback(tw->tw_rcv_saddr))
134 loopback = true;
135 }
136 if (!loopback)
137 reuse = 0;
138 }
139
140 /* With PAWS, it is safe from the viewpoint
141 of data integrity. Even without PAWS it is safe provided sequence
142 spaces do not overlap i.e. at data rates <= 80Mbit/sec.
143
144 Actually, the idea is close to VJ's one, only timestamp cache is
145 held not per host, but per port pair and TW bucket is used as state
146 holder.
147
148 If TW bucket has been already destroyed we fall back to VJ's scheme
149 and use initial timestamp retrieved from peer table.
150 */
151 if (tcptw->tw_ts_recent_stamp &&
152 (!twp || (reuse && time_after32(ktime_get_seconds(),
153 tcptw->tw_ts_recent_stamp)))) {
154 /* In case of repair and re-using TIME-WAIT sockets we still
155 * want to be sure that it is safe as above but honor the
156 * sequence numbers and time stamps set as part of the repair
157 * process.
158 *
159 * Without this check re-using a TIME-WAIT socket with TCP
160 * repair would accumulate a -1 on the repair assigned
161 * sequence number. The first time it is reused the sequence
162 * is -1, the second time -2, etc. This fixes that issue
163 * without appearing to create any others.
164 */
165 if (likely(!tp->repair)) {
166 u32 seq = tcptw->tw_snd_nxt + 65535 + 2;
167
168 if (!seq)
169 seq = 1;
170 WRITE_ONCE(tp->write_seq, seq);
171 tp->rx_opt.ts_recent = tcptw->tw_ts_recent;
172 tp->rx_opt.ts_recent_stamp = tcptw->tw_ts_recent_stamp;
173 }
174 sock_hold(sktw);
175 return 1;
176 }
177
178 return 0;
179}
180EXPORT_SYMBOL_GPL(tcp_twsk_unique);
181
182static int tcp_v4_pre_connect(struct sock *sk, struct sockaddr *uaddr,
183 int addr_len)
184{
185 /* This check is replicated from tcp_v4_connect() and intended to
186 * prevent BPF program called below from accessing bytes that are out
187 * of the bound specified by user in addr_len.
188 */
189 if (addr_len < sizeof(struct sockaddr_in))
190 return -EINVAL;
191
192 sock_owned_by_me(sk);
193
194 return BPF_CGROUP_RUN_PROG_INET4_CONNECT(sk, uaddr);
195}
196
197/* This will initiate an outgoing connection. */
198int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
199{
200 struct sockaddr_in *usin = (struct sockaddr_in *)uaddr;
201 struct inet_sock *inet = inet_sk(sk);
202 struct tcp_sock *tp = tcp_sk(sk);
203 __be16 orig_sport, orig_dport;
204 __be32 daddr, nexthop;
205 struct flowi4 *fl4;
206 struct rtable *rt;
207 int err;
208 struct ip_options_rcu *inet_opt;
209 struct inet_timewait_death_row *tcp_death_row = &sock_net(sk)->ipv4.tcp_death_row;
210
211 if (addr_len < sizeof(struct sockaddr_in))
212 return -EINVAL;
213
214 if (usin->sin_family != AF_INET)
215 return -EAFNOSUPPORT;
216
217 nexthop = daddr = usin->sin_addr.s_addr;
218 inet_opt = rcu_dereference_protected(inet->inet_opt,
219 lockdep_sock_is_held(sk));
220 if (inet_opt && inet_opt->opt.srr) {
221 if (!daddr)
222 return -EINVAL;
223 nexthop = inet_opt->opt.faddr;
224 }
225
226 orig_sport = inet->inet_sport;
227 orig_dport = usin->sin_port;
228 fl4 = &inet->cork.fl.u.ip4;
229 rt = ip_route_connect(fl4, nexthop, inet->inet_saddr,
230 RT_CONN_FLAGS(sk), sk->sk_bound_dev_if,
231 IPPROTO_TCP,
232 orig_sport, orig_dport, sk);
233 if (IS_ERR(rt)) {
234 err = PTR_ERR(rt);
235 if (err == -ENETUNREACH)
236 IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTNOROUTES);
237 return err;
238 }
239
240 if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) {
241 ip_rt_put(rt);
242 return -ENETUNREACH;
243 }
244
245 if (!inet_opt || !inet_opt->opt.srr)
246 daddr = fl4->daddr;
247
248 if (!inet->inet_saddr)
249 inet->inet_saddr = fl4->saddr;
250 sk_rcv_saddr_set(sk, inet->inet_saddr);
251
252 if (tp->rx_opt.ts_recent_stamp && inet->inet_daddr != daddr) {
253 /* Reset inherited state */
254 tp->rx_opt.ts_recent = 0;
255 tp->rx_opt.ts_recent_stamp = 0;
256 if (likely(!tp->repair))
257 WRITE_ONCE(tp->write_seq, 0);
258 }
259
260 inet->inet_dport = usin->sin_port;
261 sk_daddr_set(sk, daddr);
262
263 inet_csk(sk)->icsk_ext_hdr_len = 0;
264 if (inet_opt)
265 inet_csk(sk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
266
267 tp->rx_opt.mss_clamp = TCP_MSS_DEFAULT;
268
269 /* Socket identity is still unknown (sport may be zero).
270 * However we set state to SYN-SENT and not releasing socket
271 * lock select source port, enter ourselves into the hash tables and
272 * complete initialization after this.
273 */
274 tcp_set_state(sk, TCP_SYN_SENT);
275 err = inet_hash_connect(tcp_death_row, sk);
276 if (err)
277 goto failure;
278
279 sk_set_txhash(sk);
280
281 rt = ip_route_newports(fl4, rt, orig_sport, orig_dport,
282 inet->inet_sport, inet->inet_dport, sk);
283 if (IS_ERR(rt)) {
284 err = PTR_ERR(rt);
285 rt = NULL;
286 goto failure;
287 }
288 /* OK, now commit destination to socket. */
289 sk->sk_gso_type = SKB_GSO_TCPV4;
290 sk_setup_caps(sk, &rt->dst);
291 rt = NULL;
292
293 if (likely(!tp->repair)) {
294 if (!tp->write_seq)
295 WRITE_ONCE(tp->write_seq,
296 secure_tcp_seq(inet->inet_saddr,
297 inet->inet_daddr,
298 inet->inet_sport,
299 usin->sin_port));
300 tp->tsoffset = secure_tcp_ts_off(sock_net(sk),
301 inet->inet_saddr,
302 inet->inet_daddr);
303 }
304
305 inet->inet_id = prandom_u32();
306
307 if (tcp_fastopen_defer_connect(sk, &err))
308 return err;
309 if (err)
310 goto failure;
311
312 err = tcp_connect(sk);
313
314 if (err)
315 goto failure;
316
317 return 0;
318
319failure:
320 /*
321 * This unhashes the socket and releases the local port,
322 * if necessary.
323 */
324 tcp_set_state(sk, TCP_CLOSE);
325 ip_rt_put(rt);
326 sk->sk_route_caps = 0;
327 inet->inet_dport = 0;
328 return err;
329}
330EXPORT_SYMBOL(tcp_v4_connect);
331
332/*
333 * This routine reacts to ICMP_FRAG_NEEDED mtu indications as defined in RFC1191.
334 * It can be called through tcp_release_cb() if socket was owned by user
335 * at the time tcp_v4_err() was called to handle ICMP message.
336 */
337void tcp_v4_mtu_reduced(struct sock *sk)
338{
339 struct inet_sock *inet = inet_sk(sk);
340 struct dst_entry *dst;
341 u32 mtu;
342
343 if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE))
344 return;
345 mtu = READ_ONCE(tcp_sk(sk)->mtu_info);
346 dst = inet_csk_update_pmtu(sk, mtu);
347 if (!dst)
348 return;
349
350 /* Something is about to be wrong... Remember soft error
351 * for the case, if this connection will not able to recover.
352 */
353 if (mtu < dst_mtu(dst) && ip_dont_fragment(sk, dst))
354 sk->sk_err_soft = EMSGSIZE;
355
356 mtu = dst_mtu(dst);
357
358 if (inet->pmtudisc != IP_PMTUDISC_DONT &&
359 ip_sk_accept_pmtu(sk) &&
360 inet_csk(sk)->icsk_pmtu_cookie > mtu) {
361 tcp_sync_mss(sk, mtu);
362
363 /* Resend the TCP packet because it's
364 * clear that the old packet has been
365 * dropped. This is the new "fast" path mtu
366 * discovery.
367 */
368 tcp_simple_retransmit(sk);
369 } /* else let the usual retransmit timer handle it */
370}
371EXPORT_SYMBOL(tcp_v4_mtu_reduced);
372
373static void do_redirect(struct sk_buff *skb, struct sock *sk)
374{
375 struct dst_entry *dst = __sk_dst_check(sk, 0);
376
377 if (dst)
378 dst->ops->redirect(dst, sk, skb);
379}
380
381
382/* handle ICMP messages on TCP_NEW_SYN_RECV request sockets */
383void tcp_req_err(struct sock *sk, u32 seq, bool abort)
384{
385 struct request_sock *req = inet_reqsk(sk);
386 struct net *net = sock_net(sk);
387
388 /* ICMPs are not backlogged, hence we cannot get
389 * an established socket here.
390 */
391 if (seq != tcp_rsk(req)->snt_isn) {
392 __NET_INC_STATS(net, LINUX_MIB_OUTOFWINDOWICMPS);
393 } else if (abort) {
394 /*
395 * Still in SYN_RECV, just remove it silently.
396 * There is no good way to pass the error to the newly
397 * created socket, and POSIX does not want network
398 * errors returned from accept().
399 */
400 inet_csk_reqsk_queue_drop(req->rsk_listener, req);
401 tcp_listendrop(req->rsk_listener);
402 }
403 reqsk_put(req);
404}
405EXPORT_SYMBOL(tcp_req_err);
406
407/* TCP-LD (RFC 6069) logic */
408void tcp_ld_RTO_revert(struct sock *sk, u32 seq)
409{
410 struct inet_connection_sock *icsk = inet_csk(sk);
411 struct tcp_sock *tp = tcp_sk(sk);
412 struct sk_buff *skb;
413 s32 remaining;
414 u32 delta_us;
415
416 if (sock_owned_by_user(sk))
417 return;
418
419 if (seq != tp->snd_una || !icsk->icsk_retransmits ||
420 !icsk->icsk_backoff)
421 return;
422
423 skb = tcp_rtx_queue_head(sk);
424 if (WARN_ON_ONCE(!skb))
425 return;
426
427 icsk->icsk_backoff--;
428 icsk->icsk_rto = tp->srtt_us ? __tcp_set_rto(tp) : TCP_TIMEOUT_INIT;
429 icsk->icsk_rto = inet_csk_rto_backoff(icsk, TCP_RTO_MAX);
430
431 tcp_mstamp_refresh(tp);
432 delta_us = (u32)(tp->tcp_mstamp - tcp_skb_timestamp_us(skb));
433 remaining = icsk->icsk_rto - usecs_to_jiffies(delta_us);
434
435 if (remaining > 0) {
436 inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
437 remaining, TCP_RTO_MAX);
438 } else {
439 /* RTO revert clocked out retransmission.
440 * Will retransmit now.
441 */
442 tcp_retransmit_timer(sk);
443 }
444}
445EXPORT_SYMBOL(tcp_ld_RTO_revert);
446
447/*
448 * This routine is called by the ICMP module when it gets some
449 * sort of error condition. If err < 0 then the socket should
450 * be closed and the error returned to the user. If err > 0
451 * it's just the icmp type << 8 | icmp code. After adjustment
452 * header points to the first 8 bytes of the tcp header. We need
453 * to find the appropriate port.
454 *
455 * The locking strategy used here is very "optimistic". When
456 * someone else accesses the socket the ICMP is just dropped
457 * and for some paths there is no check at all.
458 * A more general error queue to queue errors for later handling
459 * is probably better.
460 *
461 */
462
463int tcp_v4_err(struct sk_buff *skb, u32 info)
464{
465 const struct iphdr *iph = (const struct iphdr *)skb->data;
466 struct tcphdr *th = (struct tcphdr *)(skb->data + (iph->ihl << 2));
467 struct tcp_sock *tp;
468 struct inet_sock *inet;
469 const int type = icmp_hdr(skb)->type;
470 const int code = icmp_hdr(skb)->code;
471 struct sock *sk;
472 struct request_sock *fastopen;
473 u32 seq, snd_una;
474 int err;
475 struct net *net = dev_net(skb->dev);
476
477 sk = __inet_lookup_established(net, &tcp_hashinfo, iph->daddr,
478 th->dest, iph->saddr, ntohs(th->source),
479 inet_iif(skb), 0);
480 if (!sk) {
481 __ICMP_INC_STATS(net, ICMP_MIB_INERRORS);
482 return -ENOENT;
483 }
484 if (sk->sk_state == TCP_TIME_WAIT) {
485 inet_twsk_put(inet_twsk(sk));
486 return 0;
487 }
488 seq = ntohl(th->seq);
489 if (sk->sk_state == TCP_NEW_SYN_RECV) {
490 tcp_req_err(sk, seq, type == ICMP_PARAMETERPROB ||
491 type == ICMP_TIME_EXCEEDED ||
492 (type == ICMP_DEST_UNREACH &&
493 (code == ICMP_NET_UNREACH ||
494 code == ICMP_HOST_UNREACH)));
495 return 0;
496 }
497
498 bh_lock_sock(sk);
499 /* If too many ICMPs get dropped on busy
500 * servers this needs to be solved differently.
501 * We do take care of PMTU discovery (RFC1191) special case :
502 * we can receive locally generated ICMP messages while socket is held.
503 */
504 if (sock_owned_by_user(sk)) {
505 if (!(type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED))
506 __NET_INC_STATS(net, LINUX_MIB_LOCKDROPPEDICMPS);
507 }
508 if (sk->sk_state == TCP_CLOSE)
509 goto out;
510
511 if (unlikely(iph->ttl < inet_sk(sk)->min_ttl)) {
512 __NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP);
513 goto out;
514 }
515
516 tp = tcp_sk(sk);
517 /* XXX (TFO) - tp->snd_una should be ISN (tcp_create_openreq_child() */
518 fastopen = rcu_dereference(tp->fastopen_rsk);
519 snd_una = fastopen ? tcp_rsk(fastopen)->snt_isn : tp->snd_una;
520 if (sk->sk_state != TCP_LISTEN &&
521 !between(seq, snd_una, tp->snd_nxt)) {
522 __NET_INC_STATS(net, LINUX_MIB_OUTOFWINDOWICMPS);
523 goto out;
524 }
525
526 switch (type) {
527 case ICMP_REDIRECT:
528 if (!sock_owned_by_user(sk))
529 do_redirect(skb, sk);
530 goto out;
531 case ICMP_SOURCE_QUENCH:
532 /* Just silently ignore these. */
533 goto out;
534 case ICMP_PARAMETERPROB:
535 err = EPROTO;
536 break;
537 case ICMP_DEST_UNREACH:
538 if (code > NR_ICMP_UNREACH)
539 goto out;
540
541 if (code == ICMP_FRAG_NEEDED) { /* PMTU discovery (RFC1191) */
542 /* We are not interested in TCP_LISTEN and open_requests
543 * (SYN-ACKs send out by Linux are always <576bytes so
544 * they should go through unfragmented).
545 */
546 if (sk->sk_state == TCP_LISTEN)
547 goto out;
548
549 WRITE_ONCE(tp->mtu_info, info);
550 if (!sock_owned_by_user(sk)) {
551 tcp_v4_mtu_reduced(sk);
552 } else {
553 if (!test_and_set_bit(TCP_MTU_REDUCED_DEFERRED, &sk->sk_tsq_flags))
554 sock_hold(sk);
555 }
556 goto out;
557 }
558
559 err = icmp_err_convert[code].errno;
560 /* check if this ICMP message allows revert of backoff.
561 * (see RFC 6069)
562 */
563 if (!fastopen &&
564 (code == ICMP_NET_UNREACH || code == ICMP_HOST_UNREACH))
565 tcp_ld_RTO_revert(sk, seq);
566 break;
567 case ICMP_TIME_EXCEEDED:
568 err = EHOSTUNREACH;
569 break;
570 default:
571 goto out;
572 }
573
574 switch (sk->sk_state) {
575 case TCP_SYN_SENT:
576 case TCP_SYN_RECV:
577 /* Only in fast or simultaneous open. If a fast open socket is
578 * already accepted it is treated as a connected one below.
579 */
580 if (fastopen && !fastopen->sk)
581 break;
582
583 ip_icmp_error(sk, skb, err, th->dest, info, (u8 *)th);
584
585 if (!sock_owned_by_user(sk)) {
586 sk->sk_err = err;
587
588 sk_error_report(sk);
589
590 tcp_done(sk);
591 } else {
592 sk->sk_err_soft = err;
593 }
594 goto out;
595 }
596
597 /* If we've already connected we will keep trying
598 * until we time out, or the user gives up.
599 *
600 * rfc1122 4.2.3.9 allows to consider as hard errors
601 * only PROTO_UNREACH and PORT_UNREACH (well, FRAG_FAILED too,
602 * but it is obsoleted by pmtu discovery).
603 *
604 * Note, that in modern internet, where routing is unreliable
605 * and in each dark corner broken firewalls sit, sending random
606 * errors ordered by their masters even this two messages finally lose
607 * their original sense (even Linux sends invalid PORT_UNREACHs)
608 *
609 * Now we are in compliance with RFCs.
610 * --ANK (980905)
611 */
612
613 inet = inet_sk(sk);
614 if (!sock_owned_by_user(sk) && inet->recverr) {
615 sk->sk_err = err;
616 sk_error_report(sk);
617 } else { /* Only an error on timeout */
618 sk->sk_err_soft = err;
619 }
620
621out:
622 bh_unlock_sock(sk);
623 sock_put(sk);
624 return 0;
625}
626
627void __tcp_v4_send_check(struct sk_buff *skb, __be32 saddr, __be32 daddr)
628{
629 struct tcphdr *th = tcp_hdr(skb);
630
631 th->check = ~tcp_v4_check(skb->len, saddr, daddr, 0);
632 skb->csum_start = skb_transport_header(skb) - skb->head;
633 skb->csum_offset = offsetof(struct tcphdr, check);
634}
635
636/* This routine computes an IPv4 TCP checksum. */
637void tcp_v4_send_check(struct sock *sk, struct sk_buff *skb)
638{
639 const struct inet_sock *inet = inet_sk(sk);
640
641 __tcp_v4_send_check(skb, inet->inet_saddr, inet->inet_daddr);
642}
643EXPORT_SYMBOL(tcp_v4_send_check);
644
645/*
646 * This routine will send an RST to the other tcp.
647 *
648 * Someone asks: why I NEVER use socket parameters (TOS, TTL etc.)
649 * for reset.
650 * Answer: if a packet caused RST, it is not for a socket
651 * existing in our system, if it is matched to a socket,
652 * it is just duplicate segment or bug in other side's TCP.
653 * So that we build reply only basing on parameters
654 * arrived with segment.
655 * Exception: precedence violation. We do not implement it in any case.
656 */
657
658#ifdef CONFIG_TCP_MD5SIG
659#define OPTION_BYTES TCPOLEN_MD5SIG_ALIGNED
660#else
661#define OPTION_BYTES sizeof(__be32)
662#endif
663
664static void tcp_v4_send_reset(const struct sock *sk, struct sk_buff *skb)
665{
666 const struct tcphdr *th = tcp_hdr(skb);
667 struct {
668 struct tcphdr th;
669 __be32 opt[OPTION_BYTES / sizeof(__be32)];
670 } rep;
671 struct ip_reply_arg arg;
672#ifdef CONFIG_TCP_MD5SIG
673 struct tcp_md5sig_key *key = NULL;
674 const __u8 *hash_location = NULL;
675 unsigned char newhash[16];
676 int genhash;
677 struct sock *sk1 = NULL;
678#endif
679 u64 transmit_time = 0;
680 struct sock *ctl_sk;
681 struct net *net;
682
683 /* Never send a reset in response to a reset. */
684 if (th->rst)
685 return;
686
687 /* If sk not NULL, it means we did a successful lookup and incoming
688 * route had to be correct. prequeue might have dropped our dst.
689 */
690 if (!sk && skb_rtable(skb)->rt_type != RTN_LOCAL)
691 return;
692
693 /* Swap the send and the receive. */
694 memset(&rep, 0, sizeof(rep));
695 rep.th.dest = th->source;
696 rep.th.source = th->dest;
697 rep.th.doff = sizeof(struct tcphdr) / 4;
698 rep.th.rst = 1;
699
700 if (th->ack) {
701 rep.th.seq = th->ack_seq;
702 } else {
703 rep.th.ack = 1;
704 rep.th.ack_seq = htonl(ntohl(th->seq) + th->syn + th->fin +
705 skb->len - (th->doff << 2));
706 }
707
708 memset(&arg, 0, sizeof(arg));
709 arg.iov[0].iov_base = (unsigned char *)&rep;
710 arg.iov[0].iov_len = sizeof(rep.th);
711
712 net = sk ? sock_net(sk) : dev_net(skb_dst(skb)->dev);
713#ifdef CONFIG_TCP_MD5SIG
714 rcu_read_lock();
715 hash_location = tcp_parse_md5sig_option(th);
716 if (sk && sk_fullsock(sk)) {
717 const union tcp_md5_addr *addr;
718 int l3index;
719
720 /* sdif set, means packet ingressed via a device
721 * in an L3 domain and inet_iif is set to it.
722 */
723 l3index = tcp_v4_sdif(skb) ? inet_iif(skb) : 0;
724 addr = (union tcp_md5_addr *)&ip_hdr(skb)->saddr;
725 key = tcp_md5_do_lookup(sk, l3index, addr, AF_INET);
726 } else if (hash_location) {
727 const union tcp_md5_addr *addr;
728 int sdif = tcp_v4_sdif(skb);
729 int dif = inet_iif(skb);
730 int l3index;
731
732 /*
733 * active side is lost. Try to find listening socket through
734 * source port, and then find md5 key through listening socket.
735 * we are not loose security here:
736 * Incoming packet is checked with md5 hash with finding key,
737 * no RST generated if md5 hash doesn't match.
738 */
739 sk1 = __inet_lookup_listener(net, &tcp_hashinfo, NULL, 0,
740 ip_hdr(skb)->saddr,
741 th->source, ip_hdr(skb)->daddr,
742 ntohs(th->source), dif, sdif);
743 /* don't send rst if it can't find key */
744 if (!sk1)
745 goto out;
746
747 /* sdif set, means packet ingressed via a device
748 * in an L3 domain and dif is set to it.
749 */
750 l3index = sdif ? dif : 0;
751 addr = (union tcp_md5_addr *)&ip_hdr(skb)->saddr;
752 key = tcp_md5_do_lookup(sk1, l3index, addr, AF_INET);
753 if (!key)
754 goto out;
755
756
757 genhash = tcp_v4_md5_hash_skb(newhash, key, NULL, skb);
758 if (genhash || memcmp(hash_location, newhash, 16) != 0)
759 goto out;
760
761 }
762
763 if (key) {
764 rep.opt[0] = htonl((TCPOPT_NOP << 24) |
765 (TCPOPT_NOP << 16) |
766 (TCPOPT_MD5SIG << 8) |
767 TCPOLEN_MD5SIG);
768 /* Update length and the length the header thinks exists */
769 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED;
770 rep.th.doff = arg.iov[0].iov_len / 4;
771
772 tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[1],
773 key, ip_hdr(skb)->saddr,
774 ip_hdr(skb)->daddr, &rep.th);
775 }
776#endif
777 /* Can't co-exist with TCPMD5, hence check rep.opt[0] */
778 if (rep.opt[0] == 0) {
779 __be32 mrst = mptcp_reset_option(skb);
780
781 if (mrst) {
782 rep.opt[0] = mrst;
783 arg.iov[0].iov_len += sizeof(mrst);
784 rep.th.doff = arg.iov[0].iov_len / 4;
785 }
786 }
787
788 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
789 ip_hdr(skb)->saddr, /* XXX */
790 arg.iov[0].iov_len, IPPROTO_TCP, 0);
791 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
792 arg.flags = (sk && inet_sk_transparent(sk)) ? IP_REPLY_ARG_NOSRCCHECK : 0;
793
794 /* When socket is gone, all binding information is lost.
795 * routing might fail in this case. No choice here, if we choose to force
796 * input interface, we will misroute in case of asymmetric route.
797 */
798 if (sk) {
799 arg.bound_dev_if = sk->sk_bound_dev_if;
800 if (sk_fullsock(sk))
801 trace_tcp_send_reset(sk, skb);
802 }
803
804 BUILD_BUG_ON(offsetof(struct sock, sk_bound_dev_if) !=
805 offsetof(struct inet_timewait_sock, tw_bound_dev_if));
806
807 arg.tos = ip_hdr(skb)->tos;
808 arg.uid = sock_net_uid(net, sk && sk_fullsock(sk) ? sk : NULL);
809 local_bh_disable();
810 ctl_sk = this_cpu_read(*net->ipv4.tcp_sk);
811 if (sk) {
812 ctl_sk->sk_mark = (sk->sk_state == TCP_TIME_WAIT) ?
813 inet_twsk(sk)->tw_mark : sk->sk_mark;
814 ctl_sk->sk_priority = (sk->sk_state == TCP_TIME_WAIT) ?
815 inet_twsk(sk)->tw_priority : sk->sk_priority;
816 transmit_time = tcp_transmit_time(sk);
817 }
818 ip_send_unicast_reply(ctl_sk,
819 skb, &TCP_SKB_CB(skb)->header.h4.opt,
820 ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
821 &arg, arg.iov[0].iov_len,
822 transmit_time);
823
824 ctl_sk->sk_mark = 0;
825 __TCP_INC_STATS(net, TCP_MIB_OUTSEGS);
826 __TCP_INC_STATS(net, TCP_MIB_OUTRSTS);
827 local_bh_enable();
828
829#ifdef CONFIG_TCP_MD5SIG
830out:
831 rcu_read_unlock();
832#endif
833}
834
835/* The code following below sending ACKs in SYN-RECV and TIME-WAIT states
836 outside socket context is ugly, certainly. What can I do?
837 */
838
839static void tcp_v4_send_ack(const struct sock *sk,
840 struct sk_buff *skb, u32 seq, u32 ack,
841 u32 win, u32 tsval, u32 tsecr, int oif,
842 struct tcp_md5sig_key *key,
843 int reply_flags, u8 tos)
844{
845 const struct tcphdr *th = tcp_hdr(skb);
846 struct {
847 struct tcphdr th;
848 __be32 opt[(TCPOLEN_TSTAMP_ALIGNED >> 2)
849#ifdef CONFIG_TCP_MD5SIG
850 + (TCPOLEN_MD5SIG_ALIGNED >> 2)
851#endif
852 ];
853 } rep;
854 struct net *net = sock_net(sk);
855 struct ip_reply_arg arg;
856 struct sock *ctl_sk;
857 u64 transmit_time;
858
859 memset(&rep.th, 0, sizeof(struct tcphdr));
860 memset(&arg, 0, sizeof(arg));
861
862 arg.iov[0].iov_base = (unsigned char *)&rep;
863 arg.iov[0].iov_len = sizeof(rep.th);
864 if (tsecr) {
865 rep.opt[0] = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
866 (TCPOPT_TIMESTAMP << 8) |
867 TCPOLEN_TIMESTAMP);
868 rep.opt[1] = htonl(tsval);
869 rep.opt[2] = htonl(tsecr);
870 arg.iov[0].iov_len += TCPOLEN_TSTAMP_ALIGNED;
871 }
872
873 /* Swap the send and the receive. */
874 rep.th.dest = th->source;
875 rep.th.source = th->dest;
876 rep.th.doff = arg.iov[0].iov_len / 4;
877 rep.th.seq = htonl(seq);
878 rep.th.ack_seq = htonl(ack);
879 rep.th.ack = 1;
880 rep.th.window = htons(win);
881
882#ifdef CONFIG_TCP_MD5SIG
883 if (key) {
884 int offset = (tsecr) ? 3 : 0;
885
886 rep.opt[offset++] = htonl((TCPOPT_NOP << 24) |
887 (TCPOPT_NOP << 16) |
888 (TCPOPT_MD5SIG << 8) |
889 TCPOLEN_MD5SIG);
890 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED;
891 rep.th.doff = arg.iov[0].iov_len/4;
892
893 tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[offset],
894 key, ip_hdr(skb)->saddr,
895 ip_hdr(skb)->daddr, &rep.th);
896 }
897#endif
898 arg.flags = reply_flags;
899 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
900 ip_hdr(skb)->saddr, /* XXX */
901 arg.iov[0].iov_len, IPPROTO_TCP, 0);
902 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
903 if (oif)
904 arg.bound_dev_if = oif;
905 arg.tos = tos;
906 arg.uid = sock_net_uid(net, sk_fullsock(sk) ? sk : NULL);
907 local_bh_disable();
908 ctl_sk = this_cpu_read(*net->ipv4.tcp_sk);
909 ctl_sk->sk_mark = (sk->sk_state == TCP_TIME_WAIT) ?
910 inet_twsk(sk)->tw_mark : sk->sk_mark;
911 ctl_sk->sk_priority = (sk->sk_state == TCP_TIME_WAIT) ?
912 inet_twsk(sk)->tw_priority : sk->sk_priority;
913 transmit_time = tcp_transmit_time(sk);
914 ip_send_unicast_reply(ctl_sk,
915 skb, &TCP_SKB_CB(skb)->header.h4.opt,
916 ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
917 &arg, arg.iov[0].iov_len,
918 transmit_time);
919
920 ctl_sk->sk_mark = 0;
921 __TCP_INC_STATS(net, TCP_MIB_OUTSEGS);
922 local_bh_enable();
923}
924
925static void tcp_v4_timewait_ack(struct sock *sk, struct sk_buff *skb)
926{
927 struct inet_timewait_sock *tw = inet_twsk(sk);
928 struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
929
930 tcp_v4_send_ack(sk, skb,
931 tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
932 tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
933 tcp_time_stamp_raw() + tcptw->tw_ts_offset,
934 tcptw->tw_ts_recent,
935 tw->tw_bound_dev_if,
936 tcp_twsk_md5_key(tcptw),
937 tw->tw_transparent ? IP_REPLY_ARG_NOSRCCHECK : 0,
938 tw->tw_tos
939 );
940
941 inet_twsk_put(tw);
942}
943
944static void tcp_v4_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb,
945 struct request_sock *req)
946{
947 const union tcp_md5_addr *addr;
948 int l3index;
949
950 /* sk->sk_state == TCP_LISTEN -> for regular TCP_SYN_RECV
951 * sk->sk_state == TCP_SYN_RECV -> for Fast Open.
952 */
953 u32 seq = (sk->sk_state == TCP_LISTEN) ? tcp_rsk(req)->snt_isn + 1 :
954 tcp_sk(sk)->snd_nxt;
955
956 /* RFC 7323 2.3
957 * The window field (SEG.WND) of every outgoing segment, with the
958 * exception of <SYN> segments, MUST be right-shifted by
959 * Rcv.Wind.Shift bits:
960 */
961 addr = (union tcp_md5_addr *)&ip_hdr(skb)->saddr;
962 l3index = tcp_v4_sdif(skb) ? inet_iif(skb) : 0;
963 tcp_v4_send_ack(sk, skb, seq,
964 tcp_rsk(req)->rcv_nxt,
965 req->rsk_rcv_wnd >> inet_rsk(req)->rcv_wscale,
966 tcp_time_stamp_raw() + tcp_rsk(req)->ts_off,
967 req->ts_recent,
968 0,
969 tcp_md5_do_lookup(sk, l3index, addr, AF_INET),
970 inet_rsk(req)->no_srccheck ? IP_REPLY_ARG_NOSRCCHECK : 0,
971 ip_hdr(skb)->tos);
972}
973
974/*
975 * Send a SYN-ACK after having received a SYN.
976 * This still operates on a request_sock only, not on a big
977 * socket.
978 */
979static int tcp_v4_send_synack(const struct sock *sk, struct dst_entry *dst,
980 struct flowi *fl,
981 struct request_sock *req,
982 struct tcp_fastopen_cookie *foc,
983 enum tcp_synack_type synack_type,
984 struct sk_buff *syn_skb)
985{
986 const struct inet_request_sock *ireq = inet_rsk(req);
987 struct flowi4 fl4;
988 int err = -1;
989 struct sk_buff *skb;
990 u8 tos;
991
992 /* First, grab a route. */
993 if (!dst && (dst = inet_csk_route_req(sk, &fl4, req)) == NULL)
994 return -1;
995
996 skb = tcp_make_synack(sk, dst, req, foc, synack_type, syn_skb);
997
998 if (skb) {
999 __tcp_v4_send_check(skb, ireq->ir_loc_addr, ireq->ir_rmt_addr);
1000
1001 tos = sock_net(sk)->ipv4.sysctl_tcp_reflect_tos ?
1002 (tcp_rsk(req)->syn_tos & ~INET_ECN_MASK) |
1003 (inet_sk(sk)->tos & INET_ECN_MASK) :
1004 inet_sk(sk)->tos;
1005
1006 if (!INET_ECN_is_capable(tos) &&
1007 tcp_bpf_ca_needs_ecn((struct sock *)req))
1008 tos |= INET_ECN_ECT_0;
1009
1010 rcu_read_lock();
1011 err = ip_build_and_send_pkt(skb, sk, ireq->ir_loc_addr,
1012 ireq->ir_rmt_addr,
1013 rcu_dereference(ireq->ireq_opt),
1014 tos);
1015 rcu_read_unlock();
1016 err = net_xmit_eval(err);
1017 }
1018
1019 return err;
1020}
1021
1022/*
1023 * IPv4 request_sock destructor.
1024 */
1025static void tcp_v4_reqsk_destructor(struct request_sock *req)
1026{
1027 kfree(rcu_dereference_protected(inet_rsk(req)->ireq_opt, 1));
1028}
1029
1030#ifdef CONFIG_TCP_MD5SIG
1031/*
1032 * RFC2385 MD5 checksumming requires a mapping of
1033 * IP address->MD5 Key.
1034 * We need to maintain these in the sk structure.
1035 */
1036
1037DEFINE_STATIC_KEY_FALSE(tcp_md5_needed);
1038EXPORT_SYMBOL(tcp_md5_needed);
1039
1040static bool better_md5_match(struct tcp_md5sig_key *old, struct tcp_md5sig_key *new)
1041{
1042 if (!old)
1043 return true;
1044
1045 /* l3index always overrides non-l3index */
1046 if (old->l3index && new->l3index == 0)
1047 return false;
1048 if (old->l3index == 0 && new->l3index)
1049 return true;
1050
1051 return old->prefixlen < new->prefixlen;
1052}
1053
1054/* Find the Key structure for an address. */
1055struct tcp_md5sig_key *__tcp_md5_do_lookup(const struct sock *sk, int l3index,
1056 const union tcp_md5_addr *addr,
1057 int family)
1058{
1059 const struct tcp_sock *tp = tcp_sk(sk);
1060 struct tcp_md5sig_key *key;
1061 const struct tcp_md5sig_info *md5sig;
1062 __be32 mask;
1063 struct tcp_md5sig_key *best_match = NULL;
1064 bool match;
1065
1066 /* caller either holds rcu_read_lock() or socket lock */
1067 md5sig = rcu_dereference_check(tp->md5sig_info,
1068 lockdep_sock_is_held(sk));
1069 if (!md5sig)
1070 return NULL;
1071
1072 hlist_for_each_entry_rcu(key, &md5sig->head, node,
1073 lockdep_sock_is_held(sk)) {
1074 if (key->family != family)
1075 continue;
1076 if (key->l3index && key->l3index != l3index)
1077 continue;
1078 if (family == AF_INET) {
1079 mask = inet_make_mask(key->prefixlen);
1080 match = (key->addr.a4.s_addr & mask) ==
1081 (addr->a4.s_addr & mask);
1082#if IS_ENABLED(CONFIG_IPV6)
1083 } else if (family == AF_INET6) {
1084 match = ipv6_prefix_equal(&key->addr.a6, &addr->a6,
1085 key->prefixlen);
1086#endif
1087 } else {
1088 match = false;
1089 }
1090
1091 if (match && better_md5_match(best_match, key))
1092 best_match = key;
1093 }
1094 return best_match;
1095}
1096EXPORT_SYMBOL(__tcp_md5_do_lookup);
1097
1098static struct tcp_md5sig_key *tcp_md5_do_lookup_exact(const struct sock *sk,
1099 const union tcp_md5_addr *addr,
1100 int family, u8 prefixlen,
1101 int l3index)
1102{
1103 const struct tcp_sock *tp = tcp_sk(sk);
1104 struct tcp_md5sig_key *key;
1105 unsigned int size = sizeof(struct in_addr);
1106 const struct tcp_md5sig_info *md5sig;
1107
1108 /* caller either holds rcu_read_lock() or socket lock */
1109 md5sig = rcu_dereference_check(tp->md5sig_info,
1110 lockdep_sock_is_held(sk));
1111 if (!md5sig)
1112 return NULL;
1113#if IS_ENABLED(CONFIG_IPV6)
1114 if (family == AF_INET6)
1115 size = sizeof(struct in6_addr);
1116#endif
1117 hlist_for_each_entry_rcu(key, &md5sig->head, node,
1118 lockdep_sock_is_held(sk)) {
1119 if (key->family != family)
1120 continue;
1121 if (key->l3index != l3index)
1122 continue;
1123 if (!memcmp(&key->addr, addr, size) &&
1124 key->prefixlen == prefixlen)
1125 return key;
1126 }
1127 return NULL;
1128}
1129
1130struct tcp_md5sig_key *tcp_v4_md5_lookup(const struct sock *sk,
1131 const struct sock *addr_sk)
1132{
1133 const union tcp_md5_addr *addr;
1134 int l3index;
1135
1136 l3index = l3mdev_master_ifindex_by_index(sock_net(sk),
1137 addr_sk->sk_bound_dev_if);
1138 addr = (const union tcp_md5_addr *)&addr_sk->sk_daddr;
1139 return tcp_md5_do_lookup(sk, l3index, addr, AF_INET);
1140}
1141EXPORT_SYMBOL(tcp_v4_md5_lookup);
1142
1143/* This can be called on a newly created socket, from other files */
1144int tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr,
1145 int family, u8 prefixlen, int l3index,
1146 const u8 *newkey, u8 newkeylen, gfp_t gfp)
1147{
1148 /* Add Key to the list */
1149 struct tcp_md5sig_key *key;
1150 struct tcp_sock *tp = tcp_sk(sk);
1151 struct tcp_md5sig_info *md5sig;
1152
1153 key = tcp_md5_do_lookup_exact(sk, addr, family, prefixlen, l3index);
1154 if (key) {
1155 /* Pre-existing entry - just update that one.
1156 * Note that the key might be used concurrently.
1157 * data_race() is telling kcsan that we do not care of
1158 * key mismatches, since changing MD5 key on live flows
1159 * can lead to packet drops.
1160 */
1161 data_race(memcpy(key->key, newkey, newkeylen));
1162
1163 /* Pairs with READ_ONCE() in tcp_md5_hash_key().
1164 * Also note that a reader could catch new key->keylen value
1165 * but old key->key[], this is the reason we use __GFP_ZERO
1166 * at sock_kmalloc() time below these lines.
1167 */
1168 WRITE_ONCE(key->keylen, newkeylen);
1169
1170 return 0;
1171 }
1172
1173 md5sig = rcu_dereference_protected(tp->md5sig_info,
1174 lockdep_sock_is_held(sk));
1175 if (!md5sig) {
1176 md5sig = kmalloc(sizeof(*md5sig), gfp);
1177 if (!md5sig)
1178 return -ENOMEM;
1179
1180 sk_nocaps_add(sk, NETIF_F_GSO_MASK);
1181 INIT_HLIST_HEAD(&md5sig->head);
1182 rcu_assign_pointer(tp->md5sig_info, md5sig);
1183 }
1184
1185 key = sock_kmalloc(sk, sizeof(*key), gfp | __GFP_ZERO);
1186 if (!key)
1187 return -ENOMEM;
1188 if (!tcp_alloc_md5sig_pool()) {
1189 sock_kfree_s(sk, key, sizeof(*key));
1190 return -ENOMEM;
1191 }
1192
1193 memcpy(key->key, newkey, newkeylen);
1194 key->keylen = newkeylen;
1195 key->family = family;
1196 key->prefixlen = prefixlen;
1197 key->l3index = l3index;
1198 memcpy(&key->addr, addr,
1199 (family == AF_INET6) ? sizeof(struct in6_addr) :
1200 sizeof(struct in_addr));
1201 hlist_add_head_rcu(&key->node, &md5sig->head);
1202 return 0;
1203}
1204EXPORT_SYMBOL(tcp_md5_do_add);
1205
1206int tcp_md5_do_del(struct sock *sk, const union tcp_md5_addr *addr, int family,
1207 u8 prefixlen, int l3index)
1208{
1209 struct tcp_md5sig_key *key;
1210
1211 key = tcp_md5_do_lookup_exact(sk, addr, family, prefixlen, l3index);
1212 if (!key)
1213 return -ENOENT;
1214 hlist_del_rcu(&key->node);
1215 atomic_sub(sizeof(*key), &sk->sk_omem_alloc);
1216 kfree_rcu(key, rcu);
1217 return 0;
1218}
1219EXPORT_SYMBOL(tcp_md5_do_del);
1220
1221static void tcp_clear_md5_list(struct sock *sk)
1222{
1223 struct tcp_sock *tp = tcp_sk(sk);
1224 struct tcp_md5sig_key *key;
1225 struct hlist_node *n;
1226 struct tcp_md5sig_info *md5sig;
1227
1228 md5sig = rcu_dereference_protected(tp->md5sig_info, 1);
1229
1230 hlist_for_each_entry_safe(key, n, &md5sig->head, node) {
1231 hlist_del_rcu(&key->node);
1232 atomic_sub(sizeof(*key), &sk->sk_omem_alloc);
1233 kfree_rcu(key, rcu);
1234 }
1235}
1236
1237static int tcp_v4_parse_md5_keys(struct sock *sk, int optname,
1238 sockptr_t optval, int optlen)
1239{
1240 struct tcp_md5sig cmd;
1241 struct sockaddr_in *sin = (struct sockaddr_in *)&cmd.tcpm_addr;
1242 const union tcp_md5_addr *addr;
1243 u8 prefixlen = 32;
1244 int l3index = 0;
1245
1246 if (optlen < sizeof(cmd))
1247 return -EINVAL;
1248
1249 if (copy_from_sockptr(&cmd, optval, sizeof(cmd)))
1250 return -EFAULT;
1251
1252 if (sin->sin_family != AF_INET)
1253 return -EINVAL;
1254
1255 if (optname == TCP_MD5SIG_EXT &&
1256 cmd.tcpm_flags & TCP_MD5SIG_FLAG_PREFIX) {
1257 prefixlen = cmd.tcpm_prefixlen;
1258 if (prefixlen > 32)
1259 return -EINVAL;
1260 }
1261
1262 if (optname == TCP_MD5SIG_EXT &&
1263 cmd.tcpm_flags & TCP_MD5SIG_FLAG_IFINDEX) {
1264 struct net_device *dev;
1265
1266 rcu_read_lock();
1267 dev = dev_get_by_index_rcu(sock_net(sk), cmd.tcpm_ifindex);
1268 if (dev && netif_is_l3_master(dev))
1269 l3index = dev->ifindex;
1270
1271 rcu_read_unlock();
1272
1273 /* ok to reference set/not set outside of rcu;
1274 * right now device MUST be an L3 master
1275 */
1276 if (!dev || !l3index)
1277 return -EINVAL;
1278 }
1279
1280 addr = (union tcp_md5_addr *)&sin->sin_addr.s_addr;
1281
1282 if (!cmd.tcpm_keylen)
1283 return tcp_md5_do_del(sk, addr, AF_INET, prefixlen, l3index);
1284
1285 if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN)
1286 return -EINVAL;
1287
1288 return tcp_md5_do_add(sk, addr, AF_INET, prefixlen, l3index,
1289 cmd.tcpm_key, cmd.tcpm_keylen, GFP_KERNEL);
1290}
1291
1292static int tcp_v4_md5_hash_headers(struct tcp_md5sig_pool *hp,
1293 __be32 daddr, __be32 saddr,
1294 const struct tcphdr *th, int nbytes)
1295{
1296 struct tcp4_pseudohdr *bp;
1297 struct scatterlist sg;
1298 struct tcphdr *_th;
1299
1300 bp = hp->scratch;
1301 bp->saddr = saddr;
1302 bp->daddr = daddr;
1303 bp->pad = 0;
1304 bp->protocol = IPPROTO_TCP;
1305 bp->len = cpu_to_be16(nbytes);
1306
1307 _th = (struct tcphdr *)(bp + 1);
1308 memcpy(_th, th, sizeof(*th));
1309 _th->check = 0;
1310
1311 sg_init_one(&sg, bp, sizeof(*bp) + sizeof(*th));
1312 ahash_request_set_crypt(hp->md5_req, &sg, NULL,
1313 sizeof(*bp) + sizeof(*th));
1314 return crypto_ahash_update(hp->md5_req);
1315}
1316
1317static int tcp_v4_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key,
1318 __be32 daddr, __be32 saddr, const struct tcphdr *th)
1319{
1320 struct tcp_md5sig_pool *hp;
1321 struct ahash_request *req;
1322
1323 hp = tcp_get_md5sig_pool();
1324 if (!hp)
1325 goto clear_hash_noput;
1326 req = hp->md5_req;
1327
1328 if (crypto_ahash_init(req))
1329 goto clear_hash;
1330 if (tcp_v4_md5_hash_headers(hp, daddr, saddr, th, th->doff << 2))
1331 goto clear_hash;
1332 if (tcp_md5_hash_key(hp, key))
1333 goto clear_hash;
1334 ahash_request_set_crypt(req, NULL, md5_hash, 0);
1335 if (crypto_ahash_final(req))
1336 goto clear_hash;
1337
1338 tcp_put_md5sig_pool();
1339 return 0;
1340
1341clear_hash:
1342 tcp_put_md5sig_pool();
1343clear_hash_noput:
1344 memset(md5_hash, 0, 16);
1345 return 1;
1346}
1347
1348int tcp_v4_md5_hash_skb(char *md5_hash, const struct tcp_md5sig_key *key,
1349 const struct sock *sk,
1350 const struct sk_buff *skb)
1351{
1352 struct tcp_md5sig_pool *hp;
1353 struct ahash_request *req;
1354 const struct tcphdr *th = tcp_hdr(skb);
1355 __be32 saddr, daddr;
1356
1357 if (sk) { /* valid for establish/request sockets */
1358 saddr = sk->sk_rcv_saddr;
1359 daddr = sk->sk_daddr;
1360 } else {
1361 const struct iphdr *iph = ip_hdr(skb);
1362 saddr = iph->saddr;
1363 daddr = iph->daddr;
1364 }
1365
1366 hp = tcp_get_md5sig_pool();
1367 if (!hp)
1368 goto clear_hash_noput;
1369 req = hp->md5_req;
1370
1371 if (crypto_ahash_init(req))
1372 goto clear_hash;
1373
1374 if (tcp_v4_md5_hash_headers(hp, daddr, saddr, th, skb->len))
1375 goto clear_hash;
1376 if (tcp_md5_hash_skb_data(hp, skb, th->doff << 2))
1377 goto clear_hash;
1378 if (tcp_md5_hash_key(hp, key))
1379 goto clear_hash;
1380 ahash_request_set_crypt(req, NULL, md5_hash, 0);
1381 if (crypto_ahash_final(req))
1382 goto clear_hash;
1383
1384 tcp_put_md5sig_pool();
1385 return 0;
1386
1387clear_hash:
1388 tcp_put_md5sig_pool();
1389clear_hash_noput:
1390 memset(md5_hash, 0, 16);
1391 return 1;
1392}
1393EXPORT_SYMBOL(tcp_v4_md5_hash_skb);
1394
1395#endif
1396
1397/* Called with rcu_read_lock() */
1398static bool tcp_v4_inbound_md5_hash(const struct sock *sk,
1399 const struct sk_buff *skb,
1400 int dif, int sdif)
1401{
1402#ifdef CONFIG_TCP_MD5SIG
1403 /*
1404 * This gets called for each TCP segment that arrives
1405 * so we want to be efficient.
1406 * We have 3 drop cases:
1407 * o No MD5 hash and one expected.
1408 * o MD5 hash and we're not expecting one.
1409 * o MD5 hash and its wrong.
1410 */
1411 const __u8 *hash_location = NULL;
1412 struct tcp_md5sig_key *hash_expected;
1413 const struct iphdr *iph = ip_hdr(skb);
1414 const struct tcphdr *th = tcp_hdr(skb);
1415 const union tcp_md5_addr *addr;
1416 unsigned char newhash[16];
1417 int genhash, l3index;
1418
1419 /* sdif set, means packet ingressed via a device
1420 * in an L3 domain and dif is set to the l3mdev
1421 */
1422 l3index = sdif ? dif : 0;
1423
1424 addr = (union tcp_md5_addr *)&iph->saddr;
1425 hash_expected = tcp_md5_do_lookup(sk, l3index, addr, AF_INET);
1426 hash_location = tcp_parse_md5sig_option(th);
1427
1428 /* We've parsed the options - do we have a hash? */
1429 if (!hash_expected && !hash_location)
1430 return false;
1431
1432 if (hash_expected && !hash_location) {
1433 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5NOTFOUND);
1434 return true;
1435 }
1436
1437 if (!hash_expected && hash_location) {
1438 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5UNEXPECTED);
1439 return true;
1440 }
1441
1442 /* Okay, so this is hash_expected and hash_location -
1443 * so we need to calculate the checksum.
1444 */
1445 genhash = tcp_v4_md5_hash_skb(newhash,
1446 hash_expected,
1447 NULL, skb);
1448
1449 if (genhash || memcmp(hash_location, newhash, 16) != 0) {
1450 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5FAILURE);
1451 net_info_ratelimited("MD5 Hash failed for (%pI4, %d)->(%pI4, %d)%s L3 index %d\n",
1452 &iph->saddr, ntohs(th->source),
1453 &iph->daddr, ntohs(th->dest),
1454 genhash ? " tcp_v4_calc_md5_hash failed"
1455 : "", l3index);
1456 return true;
1457 }
1458 return false;
1459#endif
1460 return false;
1461}
1462
1463static void tcp_v4_init_req(struct request_sock *req,
1464 const struct sock *sk_listener,
1465 struct sk_buff *skb)
1466{
1467 struct inet_request_sock *ireq = inet_rsk(req);
1468 struct net *net = sock_net(sk_listener);
1469
1470 sk_rcv_saddr_set(req_to_sk(req), ip_hdr(skb)->daddr);
1471 sk_daddr_set(req_to_sk(req), ip_hdr(skb)->saddr);
1472 RCU_INIT_POINTER(ireq->ireq_opt, tcp_v4_save_options(net, skb));
1473}
1474
1475static struct dst_entry *tcp_v4_route_req(const struct sock *sk,
1476 struct sk_buff *skb,
1477 struct flowi *fl,
1478 struct request_sock *req)
1479{
1480 tcp_v4_init_req(req, sk, skb);
1481
1482 if (security_inet_conn_request(sk, skb, req))
1483 return NULL;
1484
1485 return inet_csk_route_req(sk, &fl->u.ip4, req);
1486}
1487
1488struct request_sock_ops tcp_request_sock_ops __read_mostly = {
1489 .family = PF_INET,
1490 .obj_size = sizeof(struct tcp_request_sock),
1491 .rtx_syn_ack = tcp_rtx_synack,
1492 .send_ack = tcp_v4_reqsk_send_ack,
1493 .destructor = tcp_v4_reqsk_destructor,
1494 .send_reset = tcp_v4_send_reset,
1495 .syn_ack_timeout = tcp_syn_ack_timeout,
1496};
1497
1498const struct tcp_request_sock_ops tcp_request_sock_ipv4_ops = {
1499 .mss_clamp = TCP_MSS_DEFAULT,
1500#ifdef CONFIG_TCP_MD5SIG
1501 .req_md5_lookup = tcp_v4_md5_lookup,
1502 .calc_md5_hash = tcp_v4_md5_hash_skb,
1503#endif
1504#ifdef CONFIG_SYN_COOKIES
1505 .cookie_init_seq = cookie_v4_init_sequence,
1506#endif
1507 .route_req = tcp_v4_route_req,
1508 .init_seq = tcp_v4_init_seq,
1509 .init_ts_off = tcp_v4_init_ts_off,
1510 .send_synack = tcp_v4_send_synack,
1511};
1512
1513int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
1514{
1515 /* Never answer to SYNs send to broadcast or multicast */
1516 if (skb_rtable(skb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
1517 goto drop;
1518
1519 return tcp_conn_request(&tcp_request_sock_ops,
1520 &tcp_request_sock_ipv4_ops, sk, skb);
1521
1522drop:
1523 tcp_listendrop(sk);
1524 return 0;
1525}
1526EXPORT_SYMBOL(tcp_v4_conn_request);
1527
1528
1529/*
1530 * The three way handshake has completed - we got a valid synack -
1531 * now create the new socket.
1532 */
1533struct sock *tcp_v4_syn_recv_sock(const struct sock *sk, struct sk_buff *skb,
1534 struct request_sock *req,
1535 struct dst_entry *dst,
1536 struct request_sock *req_unhash,
1537 bool *own_req)
1538{
1539 struct inet_request_sock *ireq;
1540 bool found_dup_sk = false;
1541 struct inet_sock *newinet;
1542 struct tcp_sock *newtp;
1543 struct sock *newsk;
1544#ifdef CONFIG_TCP_MD5SIG
1545 const union tcp_md5_addr *addr;
1546 struct tcp_md5sig_key *key;
1547 int l3index;
1548#endif
1549 struct ip_options_rcu *inet_opt;
1550
1551 if (sk_acceptq_is_full(sk))
1552 goto exit_overflow;
1553
1554 newsk = tcp_create_openreq_child(sk, req, skb);
1555 if (!newsk)
1556 goto exit_nonewsk;
1557
1558 newsk->sk_gso_type = SKB_GSO_TCPV4;
1559 inet_sk_rx_dst_set(newsk, skb);
1560
1561 newtp = tcp_sk(newsk);
1562 newinet = inet_sk(newsk);
1563 ireq = inet_rsk(req);
1564 sk_daddr_set(newsk, ireq->ir_rmt_addr);
1565 sk_rcv_saddr_set(newsk, ireq->ir_loc_addr);
1566 newsk->sk_bound_dev_if = ireq->ir_iif;
1567 newinet->inet_saddr = ireq->ir_loc_addr;
1568 inet_opt = rcu_dereference(ireq->ireq_opt);
1569 RCU_INIT_POINTER(newinet->inet_opt, inet_opt);
1570 newinet->mc_index = inet_iif(skb);
1571 newinet->mc_ttl = ip_hdr(skb)->ttl;
1572 newinet->rcv_tos = ip_hdr(skb)->tos;
1573 inet_csk(newsk)->icsk_ext_hdr_len = 0;
1574 if (inet_opt)
1575 inet_csk(newsk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
1576 newinet->inet_id = prandom_u32();
1577
1578 /* Set ToS of the new socket based upon the value of incoming SYN.
1579 * ECT bits are set later in tcp_init_transfer().
1580 */
1581 if (sock_net(sk)->ipv4.sysctl_tcp_reflect_tos)
1582 newinet->tos = tcp_rsk(req)->syn_tos & ~INET_ECN_MASK;
1583
1584 if (!dst) {
1585 dst = inet_csk_route_child_sock(sk, newsk, req);
1586 if (!dst)
1587 goto put_and_exit;
1588 } else {
1589 /* syncookie case : see end of cookie_v4_check() */
1590 }
1591 sk_setup_caps(newsk, dst);
1592
1593 tcp_ca_openreq_child(newsk, dst);
1594
1595 tcp_sync_mss(newsk, dst_mtu(dst));
1596 newtp->advmss = tcp_mss_clamp(tcp_sk(sk), dst_metric_advmss(dst));
1597
1598 tcp_initialize_rcv_mss(newsk);
1599
1600#ifdef CONFIG_TCP_MD5SIG
1601 l3index = l3mdev_master_ifindex_by_index(sock_net(sk), ireq->ir_iif);
1602 /* Copy over the MD5 key from the original socket */
1603 addr = (union tcp_md5_addr *)&newinet->inet_daddr;
1604 key = tcp_md5_do_lookup(sk, l3index, addr, AF_INET);
1605 if (key) {
1606 /*
1607 * We're using one, so create a matching key
1608 * on the newsk structure. If we fail to get
1609 * memory, then we end up not copying the key
1610 * across. Shucks.
1611 */
1612 tcp_md5_do_add(newsk, addr, AF_INET, 32, l3index,
1613 key->key, key->keylen, GFP_ATOMIC);
1614 sk_nocaps_add(newsk, NETIF_F_GSO_MASK);
1615 }
1616#endif
1617
1618 if (__inet_inherit_port(sk, newsk) < 0)
1619 goto put_and_exit;
1620 *own_req = inet_ehash_nolisten(newsk, req_to_sk(req_unhash),
1621 &found_dup_sk);
1622 if (likely(*own_req)) {
1623 tcp_move_syn(newtp, req);
1624 ireq->ireq_opt = NULL;
1625 } else {
1626 newinet->inet_opt = NULL;
1627
1628 if (!req_unhash && found_dup_sk) {
1629 /* This code path should only be executed in the
1630 * syncookie case only
1631 */
1632 bh_unlock_sock(newsk);
1633 sock_put(newsk);
1634 newsk = NULL;
1635 }
1636 }
1637 return newsk;
1638
1639exit_overflow:
1640 NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
1641exit_nonewsk:
1642 dst_release(dst);
1643exit:
1644 tcp_listendrop(sk);
1645 return NULL;
1646put_and_exit:
1647 newinet->inet_opt = NULL;
1648 inet_csk_prepare_forced_close(newsk);
1649 tcp_done(newsk);
1650 goto exit;
1651}
1652EXPORT_SYMBOL(tcp_v4_syn_recv_sock);
1653
1654static struct sock *tcp_v4_cookie_check(struct sock *sk, struct sk_buff *skb)
1655{
1656#ifdef CONFIG_SYN_COOKIES
1657 const struct tcphdr *th = tcp_hdr(skb);
1658
1659 if (!th->syn)
1660 sk = cookie_v4_check(sk, skb);
1661#endif
1662 return sk;
1663}
1664
1665u16 tcp_v4_get_syncookie(struct sock *sk, struct iphdr *iph,
1666 struct tcphdr *th, u32 *cookie)
1667{
1668 u16 mss = 0;
1669#ifdef CONFIG_SYN_COOKIES
1670 mss = tcp_get_syncookie_mss(&tcp_request_sock_ops,
1671 &tcp_request_sock_ipv4_ops, sk, th);
1672 if (mss) {
1673 *cookie = __cookie_v4_init_sequence(iph, th, &mss);
1674 tcp_synq_overflow(sk);
1675 }
1676#endif
1677 return mss;
1678}
1679
1680INDIRECT_CALLABLE_DECLARE(struct dst_entry *ipv4_dst_check(struct dst_entry *,
1681 u32));
1682/* The socket must have it's spinlock held when we get
1683 * here, unless it is a TCP_LISTEN socket.
1684 *
1685 * We have a potential double-lock case here, so even when
1686 * doing backlog processing we use the BH locking scheme.
1687 * This is because we cannot sleep with the original spinlock
1688 * held.
1689 */
1690int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
1691{
1692 struct sock *rsk;
1693
1694 if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
1695 struct dst_entry *dst = sk->sk_rx_dst;
1696
1697 sock_rps_save_rxhash(sk, skb);
1698 sk_mark_napi_id(sk, skb);
1699 if (dst) {
1700 if (inet_sk(sk)->rx_dst_ifindex != skb->skb_iif ||
1701 !INDIRECT_CALL_1(dst->ops->check, ipv4_dst_check,
1702 dst, 0)) {
1703 dst_release(dst);
1704 sk->sk_rx_dst = NULL;
1705 }
1706 }
1707 tcp_rcv_established(sk, skb);
1708 return 0;
1709 }
1710
1711 if (tcp_checksum_complete(skb))
1712 goto csum_err;
1713
1714 if (sk->sk_state == TCP_LISTEN) {
1715 struct sock *nsk = tcp_v4_cookie_check(sk, skb);
1716
1717 if (!nsk)
1718 goto discard;
1719 if (nsk != sk) {
1720 if (tcp_child_process(sk, nsk, skb)) {
1721 rsk = nsk;
1722 goto reset;
1723 }
1724 return 0;
1725 }
1726 } else
1727 sock_rps_save_rxhash(sk, skb);
1728
1729 if (tcp_rcv_state_process(sk, skb)) {
1730 rsk = sk;
1731 goto reset;
1732 }
1733 return 0;
1734
1735reset:
1736 tcp_v4_send_reset(rsk, skb);
1737discard:
1738 kfree_skb(skb);
1739 /* Be careful here. If this function gets more complicated and
1740 * gcc suffers from register pressure on the x86, sk (in %ebx)
1741 * might be destroyed here. This current version compiles correctly,
1742 * but you have been warned.
1743 */
1744 return 0;
1745
1746csum_err:
1747 trace_tcp_bad_csum(skb);
1748 TCP_INC_STATS(sock_net(sk), TCP_MIB_CSUMERRORS);
1749 TCP_INC_STATS(sock_net(sk), TCP_MIB_INERRS);
1750 goto discard;
1751}
1752EXPORT_SYMBOL(tcp_v4_do_rcv);
1753
1754int tcp_v4_early_demux(struct sk_buff *skb)
1755{
1756 const struct iphdr *iph;
1757 const struct tcphdr *th;
1758 struct sock *sk;
1759
1760 if (skb->pkt_type != PACKET_HOST)
1761 return 0;
1762
1763 if (!pskb_may_pull(skb, skb_transport_offset(skb) + sizeof(struct tcphdr)))
1764 return 0;
1765
1766 iph = ip_hdr(skb);
1767 th = tcp_hdr(skb);
1768
1769 if (th->doff < sizeof(struct tcphdr) / 4)
1770 return 0;
1771
1772 sk = __inet_lookup_established(dev_net(skb->dev), &tcp_hashinfo,
1773 iph->saddr, th->source,
1774 iph->daddr, ntohs(th->dest),
1775 skb->skb_iif, inet_sdif(skb));
1776 if (sk) {
1777 skb->sk = sk;
1778 skb->destructor = sock_edemux;
1779 if (sk_fullsock(sk)) {
1780 struct dst_entry *dst = READ_ONCE(sk->sk_rx_dst);
1781
1782 if (dst)
1783 dst = dst_check(dst, 0);
1784 if (dst &&
1785 inet_sk(sk)->rx_dst_ifindex == skb->skb_iif)
1786 skb_dst_set_noref(skb, dst);
1787 }
1788 }
1789 return 0;
1790}
1791
1792bool tcp_add_backlog(struct sock *sk, struct sk_buff *skb)
1793{
1794 u32 limit = READ_ONCE(sk->sk_rcvbuf) + READ_ONCE(sk->sk_sndbuf);
1795 u32 tail_gso_size, tail_gso_segs;
1796 struct skb_shared_info *shinfo;
1797 const struct tcphdr *th;
1798 struct tcphdr *thtail;
1799 struct sk_buff *tail;
1800 unsigned int hdrlen;
1801 bool fragstolen;
1802 u32 gso_segs;
1803 u32 gso_size;
1804 int delta;
1805
1806 /* In case all data was pulled from skb frags (in __pskb_pull_tail()),
1807 * we can fix skb->truesize to its real value to avoid future drops.
1808 * This is valid because skb is not yet charged to the socket.
1809 * It has been noticed pure SACK packets were sometimes dropped
1810 * (if cooked by drivers without copybreak feature).
1811 */
1812 skb_condense(skb);
1813
1814 skb_dst_drop(skb);
1815
1816 if (unlikely(tcp_checksum_complete(skb))) {
1817 bh_unlock_sock(sk);
1818 trace_tcp_bad_csum(skb);
1819 __TCP_INC_STATS(sock_net(sk), TCP_MIB_CSUMERRORS);
1820 __TCP_INC_STATS(sock_net(sk), TCP_MIB_INERRS);
1821 return true;
1822 }
1823
1824 /* Attempt coalescing to last skb in backlog, even if we are
1825 * above the limits.
1826 * This is okay because skb capacity is limited to MAX_SKB_FRAGS.
1827 */
1828 th = (const struct tcphdr *)skb->data;
1829 hdrlen = th->doff * 4;
1830
1831 tail = sk->sk_backlog.tail;
1832 if (!tail)
1833 goto no_coalesce;
1834 thtail = (struct tcphdr *)tail->data;
1835
1836 if (TCP_SKB_CB(tail)->end_seq != TCP_SKB_CB(skb)->seq ||
1837 TCP_SKB_CB(tail)->ip_dsfield != TCP_SKB_CB(skb)->ip_dsfield ||
1838 ((TCP_SKB_CB(tail)->tcp_flags |
1839 TCP_SKB_CB(skb)->tcp_flags) & (TCPHDR_SYN | TCPHDR_RST | TCPHDR_URG)) ||
1840 !((TCP_SKB_CB(tail)->tcp_flags &
1841 TCP_SKB_CB(skb)->tcp_flags) & TCPHDR_ACK) ||
1842 ((TCP_SKB_CB(tail)->tcp_flags ^
1843 TCP_SKB_CB(skb)->tcp_flags) & (TCPHDR_ECE | TCPHDR_CWR)) ||
1844#ifdef CONFIG_TLS_DEVICE
1845 tail->decrypted != skb->decrypted ||
1846#endif
1847 thtail->doff != th->doff ||
1848 memcmp(thtail + 1, th + 1, hdrlen - sizeof(*th)))
1849 goto no_coalesce;
1850
1851 __skb_pull(skb, hdrlen);
1852
1853 shinfo = skb_shinfo(skb);
1854 gso_size = shinfo->gso_size ?: skb->len;
1855 gso_segs = shinfo->gso_segs ?: 1;
1856
1857 shinfo = skb_shinfo(tail);
1858 tail_gso_size = shinfo->gso_size ?: (tail->len - hdrlen);
1859 tail_gso_segs = shinfo->gso_segs ?: 1;
1860
1861 if (skb_try_coalesce(tail, skb, &fragstolen, &delta)) {
1862 TCP_SKB_CB(tail)->end_seq = TCP_SKB_CB(skb)->end_seq;
1863
1864 if (likely(!before(TCP_SKB_CB(skb)->ack_seq, TCP_SKB_CB(tail)->ack_seq))) {
1865 TCP_SKB_CB(tail)->ack_seq = TCP_SKB_CB(skb)->ack_seq;
1866 thtail->window = th->window;
1867 }
1868
1869 /* We have to update both TCP_SKB_CB(tail)->tcp_flags and
1870 * thtail->fin, so that the fast path in tcp_rcv_established()
1871 * is not entered if we append a packet with a FIN.
1872 * SYN, RST, URG are not present.
1873 * ACK is set on both packets.
1874 * PSH : we do not really care in TCP stack,
1875 * at least for 'GRO' packets.
1876 */
1877 thtail->fin |= th->fin;
1878 TCP_SKB_CB(tail)->tcp_flags |= TCP_SKB_CB(skb)->tcp_flags;
1879
1880 if (TCP_SKB_CB(skb)->has_rxtstamp) {
1881 TCP_SKB_CB(tail)->has_rxtstamp = true;
1882 tail->tstamp = skb->tstamp;
1883 skb_hwtstamps(tail)->hwtstamp = skb_hwtstamps(skb)->hwtstamp;
1884 }
1885
1886 /* Not as strict as GRO. We only need to carry mss max value */
1887 shinfo->gso_size = max(gso_size, tail_gso_size);
1888 shinfo->gso_segs = min_t(u32, gso_segs + tail_gso_segs, 0xFFFF);
1889
1890 sk->sk_backlog.len += delta;
1891 __NET_INC_STATS(sock_net(sk),
1892 LINUX_MIB_TCPBACKLOGCOALESCE);
1893 kfree_skb_partial(skb, fragstolen);
1894 return false;
1895 }
1896 __skb_push(skb, hdrlen);
1897
1898no_coalesce:
1899 /* Only socket owner can try to collapse/prune rx queues
1900 * to reduce memory overhead, so add a little headroom here.
1901 * Few sockets backlog are possibly concurrently non empty.
1902 */
1903 limit += 64*1024;
1904
1905 if (unlikely(sk_add_backlog(sk, skb, limit))) {
1906 bh_unlock_sock(sk);
1907 __NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPBACKLOGDROP);
1908 return true;
1909 }
1910 return false;
1911}
1912EXPORT_SYMBOL(tcp_add_backlog);
1913
1914int tcp_filter(struct sock *sk, struct sk_buff *skb)
1915{
1916 struct tcphdr *th = (struct tcphdr *)skb->data;
1917
1918 return sk_filter_trim_cap(sk, skb, th->doff * 4);
1919}
1920EXPORT_SYMBOL(tcp_filter);
1921
1922static void tcp_v4_restore_cb(struct sk_buff *skb)
1923{
1924 memmove(IPCB(skb), &TCP_SKB_CB(skb)->header.h4,
1925 sizeof(struct inet_skb_parm));
1926}
1927
1928static void tcp_v4_fill_cb(struct sk_buff *skb, const struct iphdr *iph,
1929 const struct tcphdr *th)
1930{
1931 /* This is tricky : We move IPCB at its correct location into TCP_SKB_CB()
1932 * barrier() makes sure compiler wont play fool^Waliasing games.
1933 */
1934 memmove(&TCP_SKB_CB(skb)->header.h4, IPCB(skb),
1935 sizeof(struct inet_skb_parm));
1936 barrier();
1937
1938 TCP_SKB_CB(skb)->seq = ntohl(th->seq);
1939 TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
1940 skb->len - th->doff * 4);
1941 TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
1942 TCP_SKB_CB(skb)->tcp_flags = tcp_flag_byte(th);
1943 TCP_SKB_CB(skb)->tcp_tw_isn = 0;
1944 TCP_SKB_CB(skb)->ip_dsfield = ipv4_get_dsfield(iph);
1945 TCP_SKB_CB(skb)->sacked = 0;
1946 TCP_SKB_CB(skb)->has_rxtstamp =
1947 skb->tstamp || skb_hwtstamps(skb)->hwtstamp;
1948}
1949
1950/*
1951 * From tcp_input.c
1952 */
1953
1954int tcp_v4_rcv(struct sk_buff *skb)
1955{
1956 struct net *net = dev_net(skb->dev);
1957 struct sk_buff *skb_to_free;
1958 int sdif = inet_sdif(skb);
1959 int dif = inet_iif(skb);
1960 const struct iphdr *iph;
1961 const struct tcphdr *th;
1962 bool refcounted;
1963 struct sock *sk;
1964 int ret;
1965
1966 if (skb->pkt_type != PACKET_HOST)
1967 goto discard_it;
1968
1969 /* Count it even if it's bad */
1970 __TCP_INC_STATS(net, TCP_MIB_INSEGS);
1971
1972 if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
1973 goto discard_it;
1974
1975 th = (const struct tcphdr *)skb->data;
1976
1977 if (unlikely(th->doff < sizeof(struct tcphdr) / 4))
1978 goto bad_packet;
1979 if (!pskb_may_pull(skb, th->doff * 4))
1980 goto discard_it;
1981
1982 /* An explanation is required here, I think.
1983 * Packet length and doff are validated by header prediction,
1984 * provided case of th->doff==0 is eliminated.
1985 * So, we defer the checks. */
1986
1987 if (skb_checksum_init(skb, IPPROTO_TCP, inet_compute_pseudo))
1988 goto csum_error;
1989
1990 th = (const struct tcphdr *)skb->data;
1991 iph = ip_hdr(skb);
1992lookup:
1993 sk = __inet_lookup_skb(&tcp_hashinfo, skb, __tcp_hdrlen(th), th->source,
1994 th->dest, sdif, &refcounted);
1995 if (!sk)
1996 goto no_tcp_socket;
1997
1998process:
1999 if (sk->sk_state == TCP_TIME_WAIT)
2000 goto do_time_wait;
2001
2002 if (sk->sk_state == TCP_NEW_SYN_RECV) {
2003 struct request_sock *req = inet_reqsk(sk);
2004 bool req_stolen = false;
2005 struct sock *nsk;
2006
2007 sk = req->rsk_listener;
2008 if (unlikely(tcp_v4_inbound_md5_hash(sk, skb, dif, sdif))) {
2009 sk_drops_add(sk, skb);
2010 reqsk_put(req);
2011 goto discard_it;
2012 }
2013 if (tcp_checksum_complete(skb)) {
2014 reqsk_put(req);
2015 goto csum_error;
2016 }
2017 if (unlikely(sk->sk_state != TCP_LISTEN)) {
2018 nsk = reuseport_migrate_sock(sk, req_to_sk(req), skb);
2019 if (!nsk) {
2020 inet_csk_reqsk_queue_drop_and_put(sk, req);
2021 goto lookup;
2022 }
2023 sk = nsk;
2024 /* reuseport_migrate_sock() has already held one sk_refcnt
2025 * before returning.
2026 */
2027 } else {
2028 /* We own a reference on the listener, increase it again
2029 * as we might lose it too soon.
2030 */
2031 sock_hold(sk);
2032 }
2033 refcounted = true;
2034 nsk = NULL;
2035 if (!tcp_filter(sk, skb)) {
2036 th = (const struct tcphdr *)skb->data;
2037 iph = ip_hdr(skb);
2038 tcp_v4_fill_cb(skb, iph, th);
2039 nsk = tcp_check_req(sk, skb, req, false, &req_stolen);
2040 }
2041 if (!nsk) {
2042 reqsk_put(req);
2043 if (req_stolen) {
2044 /* Another cpu got exclusive access to req
2045 * and created a full blown socket.
2046 * Try to feed this packet to this socket
2047 * instead of discarding it.
2048 */
2049 tcp_v4_restore_cb(skb);
2050 sock_put(sk);
2051 goto lookup;
2052 }
2053 goto discard_and_relse;
2054 }
2055 if (nsk == sk) {
2056 reqsk_put(req);
2057 tcp_v4_restore_cb(skb);
2058 } else if (tcp_child_process(sk, nsk, skb)) {
2059 tcp_v4_send_reset(nsk, skb);
2060 goto discard_and_relse;
2061 } else {
2062 sock_put(sk);
2063 return 0;
2064 }
2065 }
2066 if (unlikely(iph->ttl < inet_sk(sk)->min_ttl)) {
2067 __NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP);
2068 goto discard_and_relse;
2069 }
2070
2071 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
2072 goto discard_and_relse;
2073
2074 if (tcp_v4_inbound_md5_hash(sk, skb, dif, sdif))
2075 goto discard_and_relse;
2076
2077 nf_reset_ct(skb);
2078
2079 if (tcp_filter(sk, skb))
2080 goto discard_and_relse;
2081 th = (const struct tcphdr *)skb->data;
2082 iph = ip_hdr(skb);
2083 tcp_v4_fill_cb(skb, iph, th);
2084
2085 skb->dev = NULL;
2086
2087 if (sk->sk_state == TCP_LISTEN) {
2088 ret = tcp_v4_do_rcv(sk, skb);
2089 goto put_and_return;
2090 }
2091
2092 sk_incoming_cpu_update(sk);
2093
2094 bh_lock_sock_nested(sk);
2095 tcp_segs_in(tcp_sk(sk), skb);
2096 ret = 0;
2097 if (!sock_owned_by_user(sk)) {
2098 skb_to_free = sk->sk_rx_skb_cache;
2099 sk->sk_rx_skb_cache = NULL;
2100 ret = tcp_v4_do_rcv(sk, skb);
2101 } else {
2102 if (tcp_add_backlog(sk, skb))
2103 goto discard_and_relse;
2104 skb_to_free = NULL;
2105 }
2106 bh_unlock_sock(sk);
2107 if (skb_to_free)
2108 __kfree_skb(skb_to_free);
2109
2110put_and_return:
2111 if (refcounted)
2112 sock_put(sk);
2113
2114 return ret;
2115
2116no_tcp_socket:
2117 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
2118 goto discard_it;
2119
2120 tcp_v4_fill_cb(skb, iph, th);
2121
2122 if (tcp_checksum_complete(skb)) {
2123csum_error:
2124 trace_tcp_bad_csum(skb);
2125 __TCP_INC_STATS(net, TCP_MIB_CSUMERRORS);
2126bad_packet:
2127 __TCP_INC_STATS(net, TCP_MIB_INERRS);
2128 } else {
2129 tcp_v4_send_reset(NULL, skb);
2130 }
2131
2132discard_it:
2133 /* Discard frame. */
2134 kfree_skb(skb);
2135 return 0;
2136
2137discard_and_relse:
2138 sk_drops_add(sk, skb);
2139 if (refcounted)
2140 sock_put(sk);
2141 goto discard_it;
2142
2143do_time_wait:
2144 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
2145 inet_twsk_put(inet_twsk(sk));
2146 goto discard_it;
2147 }
2148
2149 tcp_v4_fill_cb(skb, iph, th);
2150
2151 if (tcp_checksum_complete(skb)) {
2152 inet_twsk_put(inet_twsk(sk));
2153 goto csum_error;
2154 }
2155 switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) {
2156 case TCP_TW_SYN: {
2157 struct sock *sk2 = inet_lookup_listener(dev_net(skb->dev),
2158 &tcp_hashinfo, skb,
2159 __tcp_hdrlen(th),
2160 iph->saddr, th->source,
2161 iph->daddr, th->dest,
2162 inet_iif(skb),
2163 sdif);
2164 if (sk2) {
2165 inet_twsk_deschedule_put(inet_twsk(sk));
2166 sk = sk2;
2167 tcp_v4_restore_cb(skb);
2168 refcounted = false;
2169 goto process;
2170 }
2171 }
2172 /* to ACK */
2173 fallthrough;
2174 case TCP_TW_ACK:
2175 tcp_v4_timewait_ack(sk, skb);
2176 break;
2177 case TCP_TW_RST:
2178 tcp_v4_send_reset(sk, skb);
2179 inet_twsk_deschedule_put(inet_twsk(sk));
2180 goto discard_it;
2181 case TCP_TW_SUCCESS:;
2182 }
2183 goto discard_it;
2184}
2185
2186static struct timewait_sock_ops tcp_timewait_sock_ops = {
2187 .twsk_obj_size = sizeof(struct tcp_timewait_sock),
2188 .twsk_unique = tcp_twsk_unique,
2189 .twsk_destructor= tcp_twsk_destructor,
2190};
2191
2192void inet_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb)
2193{
2194 struct dst_entry *dst = skb_dst(skb);
2195
2196 if (dst && dst_hold_safe(dst)) {
2197 sk->sk_rx_dst = dst;
2198 inet_sk(sk)->rx_dst_ifindex = skb->skb_iif;
2199 }
2200}
2201EXPORT_SYMBOL(inet_sk_rx_dst_set);
2202
2203const struct inet_connection_sock_af_ops ipv4_specific = {
2204 .queue_xmit = ip_queue_xmit,
2205 .send_check = tcp_v4_send_check,
2206 .rebuild_header = inet_sk_rebuild_header,
2207 .sk_rx_dst_set = inet_sk_rx_dst_set,
2208 .conn_request = tcp_v4_conn_request,
2209 .syn_recv_sock = tcp_v4_syn_recv_sock,
2210 .net_header_len = sizeof(struct iphdr),
2211 .setsockopt = ip_setsockopt,
2212 .getsockopt = ip_getsockopt,
2213 .addr2sockaddr = inet_csk_addr2sockaddr,
2214 .sockaddr_len = sizeof(struct sockaddr_in),
2215 .mtu_reduced = tcp_v4_mtu_reduced,
2216};
2217EXPORT_SYMBOL(ipv4_specific);
2218
2219#ifdef CONFIG_TCP_MD5SIG
2220static const struct tcp_sock_af_ops tcp_sock_ipv4_specific = {
2221 .md5_lookup = tcp_v4_md5_lookup,
2222 .calc_md5_hash = tcp_v4_md5_hash_skb,
2223 .md5_parse = tcp_v4_parse_md5_keys,
2224};
2225#endif
2226
2227/* NOTE: A lot of things set to zero explicitly by call to
2228 * sk_alloc() so need not be done here.
2229 */
2230static int tcp_v4_init_sock(struct sock *sk)
2231{
2232 struct inet_connection_sock *icsk = inet_csk(sk);
2233
2234 tcp_init_sock(sk);
2235
2236 icsk->icsk_af_ops = &ipv4_specific;
2237
2238#ifdef CONFIG_TCP_MD5SIG
2239 tcp_sk(sk)->af_specific = &tcp_sock_ipv4_specific;
2240#endif
2241
2242 return 0;
2243}
2244
2245void tcp_v4_destroy_sock(struct sock *sk)
2246{
2247 struct tcp_sock *tp = tcp_sk(sk);
2248
2249 trace_tcp_destroy_sock(sk);
2250
2251 tcp_clear_xmit_timers(sk);
2252
2253 tcp_cleanup_congestion_control(sk);
2254
2255 tcp_cleanup_ulp(sk);
2256
2257 /* Cleanup up the write buffer. */
2258 tcp_write_queue_purge(sk);
2259
2260 /* Check if we want to disable active TFO */
2261 tcp_fastopen_active_disable_ofo_check(sk);
2262
2263 /* Cleans up our, hopefully empty, out_of_order_queue. */
2264 skb_rbtree_purge(&tp->out_of_order_queue);
2265
2266#ifdef CONFIG_TCP_MD5SIG
2267 /* Clean up the MD5 key list, if any */
2268 if (tp->md5sig_info) {
2269 tcp_clear_md5_list(sk);
2270 kfree_rcu(rcu_dereference_protected(tp->md5sig_info, 1), rcu);
2271 tp->md5sig_info = NULL;
2272 }
2273#endif
2274
2275 /* Clean up a referenced TCP bind bucket. */
2276 if (inet_csk(sk)->icsk_bind_hash)
2277 inet_put_port(sk);
2278
2279 BUG_ON(rcu_access_pointer(tp->fastopen_rsk));
2280
2281 /* If socket is aborted during connect operation */
2282 tcp_free_fastopen_req(tp);
2283 tcp_fastopen_destroy_cipher(sk);
2284 tcp_saved_syn_free(tp);
2285
2286 sk_sockets_allocated_dec(sk);
2287}
2288EXPORT_SYMBOL(tcp_v4_destroy_sock);
2289
2290#ifdef CONFIG_PROC_FS
2291/* Proc filesystem TCP sock list dumping. */
2292
2293/*
2294 * Get next listener socket follow cur. If cur is NULL, get first socket
2295 * starting from bucket given in st->bucket; when st->bucket is zero the
2296 * very first socket in the hash table is returned.
2297 */
2298static void *listening_get_next(struct seq_file *seq, void *cur)
2299{
2300 struct tcp_seq_afinfo *afinfo;
2301 struct tcp_iter_state *st = seq->private;
2302 struct net *net = seq_file_net(seq);
2303 struct inet_listen_hashbucket *ilb;
2304 struct hlist_nulls_node *node;
2305 struct sock *sk = cur;
2306
2307 if (st->bpf_seq_afinfo)
2308 afinfo = st->bpf_seq_afinfo;
2309 else
2310 afinfo = PDE_DATA(file_inode(seq->file));
2311
2312 if (!sk) {
2313get_head:
2314 ilb = &tcp_hashinfo.listening_hash[st->bucket];
2315 spin_lock(&ilb->lock);
2316 sk = sk_nulls_head(&ilb->nulls_head);
2317 st->offset = 0;
2318 goto get_sk;
2319 }
2320 ilb = &tcp_hashinfo.listening_hash[st->bucket];
2321 ++st->num;
2322 ++st->offset;
2323
2324 sk = sk_nulls_next(sk);
2325get_sk:
2326 sk_nulls_for_each_from(sk, node) {
2327 if (!net_eq(sock_net(sk), net))
2328 continue;
2329 if (afinfo->family == AF_UNSPEC ||
2330 sk->sk_family == afinfo->family)
2331 return sk;
2332 }
2333 spin_unlock(&ilb->lock);
2334 st->offset = 0;
2335 if (++st->bucket < INET_LHTABLE_SIZE)
2336 goto get_head;
2337 return NULL;
2338}
2339
2340static void *listening_get_idx(struct seq_file *seq, loff_t *pos)
2341{
2342 struct tcp_iter_state *st = seq->private;
2343 void *rc;
2344
2345 st->bucket = 0;
2346 st->offset = 0;
2347 rc = listening_get_next(seq, NULL);
2348
2349 while (rc && *pos) {
2350 rc = listening_get_next(seq, rc);
2351 --*pos;
2352 }
2353 return rc;
2354}
2355
2356static inline bool empty_bucket(const struct tcp_iter_state *st)
2357{
2358 return hlist_nulls_empty(&tcp_hashinfo.ehash[st->bucket].chain);
2359}
2360
2361/*
2362 * Get first established socket starting from bucket given in st->bucket.
2363 * If st->bucket is zero, the very first socket in the hash is returned.
2364 */
2365static void *established_get_first(struct seq_file *seq)
2366{
2367 struct tcp_seq_afinfo *afinfo;
2368 struct tcp_iter_state *st = seq->private;
2369 struct net *net = seq_file_net(seq);
2370 void *rc = NULL;
2371
2372 if (st->bpf_seq_afinfo)
2373 afinfo = st->bpf_seq_afinfo;
2374 else
2375 afinfo = PDE_DATA(file_inode(seq->file));
2376
2377 st->offset = 0;
2378 for (; st->bucket <= tcp_hashinfo.ehash_mask; ++st->bucket) {
2379 struct sock *sk;
2380 struct hlist_nulls_node *node;
2381 spinlock_t *lock = inet_ehash_lockp(&tcp_hashinfo, st->bucket);
2382
2383 /* Lockless fast path for the common case of empty buckets */
2384 if (empty_bucket(st))
2385 continue;
2386
2387 spin_lock_bh(lock);
2388 sk_nulls_for_each(sk, node, &tcp_hashinfo.ehash[st->bucket].chain) {
2389 if ((afinfo->family != AF_UNSPEC &&
2390 sk->sk_family != afinfo->family) ||
2391 !net_eq(sock_net(sk), net)) {
2392 continue;
2393 }
2394 rc = sk;
2395 goto out;
2396 }
2397 spin_unlock_bh(lock);
2398 }
2399out:
2400 return rc;
2401}
2402
2403static void *established_get_next(struct seq_file *seq, void *cur)
2404{
2405 struct tcp_seq_afinfo *afinfo;
2406 struct sock *sk = cur;
2407 struct hlist_nulls_node *node;
2408 struct tcp_iter_state *st = seq->private;
2409 struct net *net = seq_file_net(seq);
2410
2411 if (st->bpf_seq_afinfo)
2412 afinfo = st->bpf_seq_afinfo;
2413 else
2414 afinfo = PDE_DATA(file_inode(seq->file));
2415
2416 ++st->num;
2417 ++st->offset;
2418
2419 sk = sk_nulls_next(sk);
2420
2421 sk_nulls_for_each_from(sk, node) {
2422 if ((afinfo->family == AF_UNSPEC ||
2423 sk->sk_family == afinfo->family) &&
2424 net_eq(sock_net(sk), net))
2425 return sk;
2426 }
2427
2428 spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
2429 ++st->bucket;
2430 return established_get_first(seq);
2431}
2432
2433static void *established_get_idx(struct seq_file *seq, loff_t pos)
2434{
2435 struct tcp_iter_state *st = seq->private;
2436 void *rc;
2437
2438 st->bucket = 0;
2439 rc = established_get_first(seq);
2440
2441 while (rc && pos) {
2442 rc = established_get_next(seq, rc);
2443 --pos;
2444 }
2445 return rc;
2446}
2447
2448static void *tcp_get_idx(struct seq_file *seq, loff_t pos)
2449{
2450 void *rc;
2451 struct tcp_iter_state *st = seq->private;
2452
2453 st->state = TCP_SEQ_STATE_LISTENING;
2454 rc = listening_get_idx(seq, &pos);
2455
2456 if (!rc) {
2457 st->state = TCP_SEQ_STATE_ESTABLISHED;
2458 rc = established_get_idx(seq, pos);
2459 }
2460
2461 return rc;
2462}
2463
2464static void *tcp_seek_last_pos(struct seq_file *seq)
2465{
2466 struct tcp_iter_state *st = seq->private;
2467 int bucket = st->bucket;
2468 int offset = st->offset;
2469 int orig_num = st->num;
2470 void *rc = NULL;
2471
2472 switch (st->state) {
2473 case TCP_SEQ_STATE_LISTENING:
2474 if (st->bucket >= INET_LHTABLE_SIZE)
2475 break;
2476 st->state = TCP_SEQ_STATE_LISTENING;
2477 rc = listening_get_next(seq, NULL);
2478 while (offset-- && rc && bucket == st->bucket)
2479 rc = listening_get_next(seq, rc);
2480 if (rc)
2481 break;
2482 st->bucket = 0;
2483 st->state = TCP_SEQ_STATE_ESTABLISHED;
2484 fallthrough;
2485 case TCP_SEQ_STATE_ESTABLISHED:
2486 if (st->bucket > tcp_hashinfo.ehash_mask)
2487 break;
2488 rc = established_get_first(seq);
2489 while (offset-- && rc && bucket == st->bucket)
2490 rc = established_get_next(seq, rc);
2491 }
2492
2493 st->num = orig_num;
2494
2495 return rc;
2496}
2497
2498void *tcp_seq_start(struct seq_file *seq, loff_t *pos)
2499{
2500 struct tcp_iter_state *st = seq->private;
2501 void *rc;
2502
2503 if (*pos && *pos == st->last_pos) {
2504 rc = tcp_seek_last_pos(seq);
2505 if (rc)
2506 goto out;
2507 }
2508
2509 st->state = TCP_SEQ_STATE_LISTENING;
2510 st->num = 0;
2511 st->bucket = 0;
2512 st->offset = 0;
2513 rc = *pos ? tcp_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
2514
2515out:
2516 st->last_pos = *pos;
2517 return rc;
2518}
2519EXPORT_SYMBOL(tcp_seq_start);
2520
2521void *tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2522{
2523 struct tcp_iter_state *st = seq->private;
2524 void *rc = NULL;
2525
2526 if (v == SEQ_START_TOKEN) {
2527 rc = tcp_get_idx(seq, 0);
2528 goto out;
2529 }
2530
2531 switch (st->state) {
2532 case TCP_SEQ_STATE_LISTENING:
2533 rc = listening_get_next(seq, v);
2534 if (!rc) {
2535 st->state = TCP_SEQ_STATE_ESTABLISHED;
2536 st->bucket = 0;
2537 st->offset = 0;
2538 rc = established_get_first(seq);
2539 }
2540 break;
2541 case TCP_SEQ_STATE_ESTABLISHED:
2542 rc = established_get_next(seq, v);
2543 break;
2544 }
2545out:
2546 ++*pos;
2547 st->last_pos = *pos;
2548 return rc;
2549}
2550EXPORT_SYMBOL(tcp_seq_next);
2551
2552void tcp_seq_stop(struct seq_file *seq, void *v)
2553{
2554 struct tcp_iter_state *st = seq->private;
2555
2556 switch (st->state) {
2557 case TCP_SEQ_STATE_LISTENING:
2558 if (v != SEQ_START_TOKEN)
2559 spin_unlock(&tcp_hashinfo.listening_hash[st->bucket].lock);
2560 break;
2561 case TCP_SEQ_STATE_ESTABLISHED:
2562 if (v)
2563 spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
2564 break;
2565 }
2566}
2567EXPORT_SYMBOL(tcp_seq_stop);
2568
2569static void get_openreq4(const struct request_sock *req,
2570 struct seq_file *f, int i)
2571{
2572 const struct inet_request_sock *ireq = inet_rsk(req);
2573 long delta = req->rsk_timer.expires - jiffies;
2574
2575 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2576 " %02X %08X:%08X %02X:%08lX %08X %5u %8d %u %d %pK",
2577 i,
2578 ireq->ir_loc_addr,
2579 ireq->ir_num,
2580 ireq->ir_rmt_addr,
2581 ntohs(ireq->ir_rmt_port),
2582 TCP_SYN_RECV,
2583 0, 0, /* could print option size, but that is af dependent. */
2584 1, /* timers active (only the expire timer) */
2585 jiffies_delta_to_clock_t(delta),
2586 req->num_timeout,
2587 from_kuid_munged(seq_user_ns(f),
2588 sock_i_uid(req->rsk_listener)),
2589 0, /* non standard timer */
2590 0, /* open_requests have no inode */
2591 0,
2592 req);
2593}
2594
2595static void get_tcp4_sock(struct sock *sk, struct seq_file *f, int i)
2596{
2597 int timer_active;
2598 unsigned long timer_expires;
2599 const struct tcp_sock *tp = tcp_sk(sk);
2600 const struct inet_connection_sock *icsk = inet_csk(sk);
2601 const struct inet_sock *inet = inet_sk(sk);
2602 const struct fastopen_queue *fastopenq = &icsk->icsk_accept_queue.fastopenq;
2603 __be32 dest = inet->inet_daddr;
2604 __be32 src = inet->inet_rcv_saddr;
2605 __u16 destp = ntohs(inet->inet_dport);
2606 __u16 srcp = ntohs(inet->inet_sport);
2607 int rx_queue;
2608 int state;
2609
2610 if (icsk->icsk_pending == ICSK_TIME_RETRANS ||
2611 icsk->icsk_pending == ICSK_TIME_REO_TIMEOUT ||
2612 icsk->icsk_pending == ICSK_TIME_LOSS_PROBE) {
2613 timer_active = 1;
2614 timer_expires = icsk->icsk_timeout;
2615 } else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
2616 timer_active = 4;
2617 timer_expires = icsk->icsk_timeout;
2618 } else if (timer_pending(&sk->sk_timer)) {
2619 timer_active = 2;
2620 timer_expires = sk->sk_timer.expires;
2621 } else {
2622 timer_active = 0;
2623 timer_expires = jiffies;
2624 }
2625
2626 state = inet_sk_state_load(sk);
2627 if (state == TCP_LISTEN)
2628 rx_queue = READ_ONCE(sk->sk_ack_backlog);
2629 else
2630 /* Because we don't lock the socket,
2631 * we might find a transient negative value.
2632 */
2633 rx_queue = max_t(int, READ_ONCE(tp->rcv_nxt) -
2634 READ_ONCE(tp->copied_seq), 0);
2635
2636 seq_printf(f, "%4d: %08X:%04X %08X:%04X %02X %08X:%08X %02X:%08lX "
2637 "%08X %5u %8d %lu %d %pK %lu %lu %u %u %d",
2638 i, src, srcp, dest, destp, state,
2639 READ_ONCE(tp->write_seq) - tp->snd_una,
2640 rx_queue,
2641 timer_active,
2642 jiffies_delta_to_clock_t(timer_expires - jiffies),
2643 icsk->icsk_retransmits,
2644 from_kuid_munged(seq_user_ns(f), sock_i_uid(sk)),
2645 icsk->icsk_probes_out,
2646 sock_i_ino(sk),
2647 refcount_read(&sk->sk_refcnt), sk,
2648 jiffies_to_clock_t(icsk->icsk_rto),
2649 jiffies_to_clock_t(icsk->icsk_ack.ato),
2650 (icsk->icsk_ack.quick << 1) | inet_csk_in_pingpong_mode(sk),
2651 tp->snd_cwnd,
2652 state == TCP_LISTEN ?
2653 fastopenq->max_qlen :
2654 (tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh));
2655}
2656
2657static void get_timewait4_sock(const struct inet_timewait_sock *tw,
2658 struct seq_file *f, int i)
2659{
2660 long delta = tw->tw_timer.expires - jiffies;
2661 __be32 dest, src;
2662 __u16 destp, srcp;
2663
2664 dest = tw->tw_daddr;
2665 src = tw->tw_rcv_saddr;
2666 destp = ntohs(tw->tw_dport);
2667 srcp = ntohs(tw->tw_sport);
2668
2669 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2670 " %02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK",
2671 i, src, srcp, dest, destp, tw->tw_substate, 0, 0,
2672 3, jiffies_delta_to_clock_t(delta), 0, 0, 0, 0,
2673 refcount_read(&tw->tw_refcnt), tw);
2674}
2675
2676#define TMPSZ 150
2677
2678static int tcp4_seq_show(struct seq_file *seq, void *v)
2679{
2680 struct tcp_iter_state *st;
2681 struct sock *sk = v;
2682
2683 seq_setwidth(seq, TMPSZ - 1);
2684 if (v == SEQ_START_TOKEN) {
2685 seq_puts(seq, " sl local_address rem_address st tx_queue "
2686 "rx_queue tr tm->when retrnsmt uid timeout "
2687 "inode");
2688 goto out;
2689 }
2690 st = seq->private;
2691
2692 if (sk->sk_state == TCP_TIME_WAIT)
2693 get_timewait4_sock(v, seq, st->num);
2694 else if (sk->sk_state == TCP_NEW_SYN_RECV)
2695 get_openreq4(v, seq, st->num);
2696 else
2697 get_tcp4_sock(v, seq, st->num);
2698out:
2699 seq_pad(seq, '\n');
2700 return 0;
2701}
2702
2703#ifdef CONFIG_BPF_SYSCALL
2704struct bpf_iter__tcp {
2705 __bpf_md_ptr(struct bpf_iter_meta *, meta);
2706 __bpf_md_ptr(struct sock_common *, sk_common);
2707 uid_t uid __aligned(8);
2708};
2709
2710static int tcp_prog_seq_show(struct bpf_prog *prog, struct bpf_iter_meta *meta,
2711 struct sock_common *sk_common, uid_t uid)
2712{
2713 struct bpf_iter__tcp ctx;
2714
2715 meta->seq_num--; /* skip SEQ_START_TOKEN */
2716 ctx.meta = meta;
2717 ctx.sk_common = sk_common;
2718 ctx.uid = uid;
2719 return bpf_iter_run_prog(prog, &ctx);
2720}
2721
2722static int bpf_iter_tcp_seq_show(struct seq_file *seq, void *v)
2723{
2724 struct bpf_iter_meta meta;
2725 struct bpf_prog *prog;
2726 struct sock *sk = v;
2727 uid_t uid;
2728
2729 if (v == SEQ_START_TOKEN)
2730 return 0;
2731
2732 if (sk->sk_state == TCP_TIME_WAIT) {
2733 uid = 0;
2734 } else if (sk->sk_state == TCP_NEW_SYN_RECV) {
2735 const struct request_sock *req = v;
2736
2737 uid = from_kuid_munged(seq_user_ns(seq),
2738 sock_i_uid(req->rsk_listener));
2739 } else {
2740 uid = from_kuid_munged(seq_user_ns(seq), sock_i_uid(sk));
2741 }
2742
2743 meta.seq = seq;
2744 prog = bpf_iter_get_info(&meta, false);
2745 return tcp_prog_seq_show(prog, &meta, v, uid);
2746}
2747
2748static void bpf_iter_tcp_seq_stop(struct seq_file *seq, void *v)
2749{
2750 struct bpf_iter_meta meta;
2751 struct bpf_prog *prog;
2752
2753 if (!v) {
2754 meta.seq = seq;
2755 prog = bpf_iter_get_info(&meta, true);
2756 if (prog)
2757 (void)tcp_prog_seq_show(prog, &meta, v, 0);
2758 }
2759
2760 tcp_seq_stop(seq, v);
2761}
2762
2763static const struct seq_operations bpf_iter_tcp_seq_ops = {
2764 .show = bpf_iter_tcp_seq_show,
2765 .start = tcp_seq_start,
2766 .next = tcp_seq_next,
2767 .stop = bpf_iter_tcp_seq_stop,
2768};
2769#endif
2770
2771static const struct seq_operations tcp4_seq_ops = {
2772 .show = tcp4_seq_show,
2773 .start = tcp_seq_start,
2774 .next = tcp_seq_next,
2775 .stop = tcp_seq_stop,
2776};
2777
2778static struct tcp_seq_afinfo tcp4_seq_afinfo = {
2779 .family = AF_INET,
2780};
2781
2782static int __net_init tcp4_proc_init_net(struct net *net)
2783{
2784 if (!proc_create_net_data("tcp", 0444, net->proc_net, &tcp4_seq_ops,
2785 sizeof(struct tcp_iter_state), &tcp4_seq_afinfo))
2786 return -ENOMEM;
2787 return 0;
2788}
2789
2790static void __net_exit tcp4_proc_exit_net(struct net *net)
2791{
2792 remove_proc_entry("tcp", net->proc_net);
2793}
2794
2795static struct pernet_operations tcp4_net_ops = {
2796 .init = tcp4_proc_init_net,
2797 .exit = tcp4_proc_exit_net,
2798};
2799
2800int __init tcp4_proc_init(void)
2801{
2802 return register_pernet_subsys(&tcp4_net_ops);
2803}
2804
2805void tcp4_proc_exit(void)
2806{
2807 unregister_pernet_subsys(&tcp4_net_ops);
2808}
2809#endif /* CONFIG_PROC_FS */
2810
2811/* @wake is one when sk_stream_write_space() calls us.
2812 * This sends EPOLLOUT only if notsent_bytes is half the limit.
2813 * This mimics the strategy used in sock_def_write_space().
2814 */
2815bool tcp_stream_memory_free(const struct sock *sk, int wake)
2816{
2817 const struct tcp_sock *tp = tcp_sk(sk);
2818 u32 notsent_bytes = READ_ONCE(tp->write_seq) -
2819 READ_ONCE(tp->snd_nxt);
2820
2821 return (notsent_bytes << wake) < tcp_notsent_lowat(tp);
2822}
2823EXPORT_SYMBOL(tcp_stream_memory_free);
2824
2825struct proto tcp_prot = {
2826 .name = "TCP",
2827 .owner = THIS_MODULE,
2828 .close = tcp_close,
2829 .pre_connect = tcp_v4_pre_connect,
2830 .connect = tcp_v4_connect,
2831 .disconnect = tcp_disconnect,
2832 .accept = inet_csk_accept,
2833 .ioctl = tcp_ioctl,
2834 .init = tcp_v4_init_sock,
2835 .destroy = tcp_v4_destroy_sock,
2836 .shutdown = tcp_shutdown,
2837 .setsockopt = tcp_setsockopt,
2838 .getsockopt = tcp_getsockopt,
2839 .bpf_bypass_getsockopt = tcp_bpf_bypass_getsockopt,
2840 .keepalive = tcp_set_keepalive,
2841 .recvmsg = tcp_recvmsg,
2842 .sendmsg = tcp_sendmsg,
2843 .sendpage = tcp_sendpage,
2844 .backlog_rcv = tcp_v4_do_rcv,
2845 .release_cb = tcp_release_cb,
2846 .hash = inet_hash,
2847 .unhash = inet_unhash,
2848 .get_port = inet_csk_get_port,
2849#ifdef CONFIG_BPF_SYSCALL
2850 .psock_update_sk_prot = tcp_bpf_update_proto,
2851#endif
2852 .enter_memory_pressure = tcp_enter_memory_pressure,
2853 .leave_memory_pressure = tcp_leave_memory_pressure,
2854 .stream_memory_free = tcp_stream_memory_free,
2855 .sockets_allocated = &tcp_sockets_allocated,
2856 .orphan_count = &tcp_orphan_count,
2857 .memory_allocated = &tcp_memory_allocated,
2858 .memory_pressure = &tcp_memory_pressure,
2859 .sysctl_mem = sysctl_tcp_mem,
2860 .sysctl_wmem_offset = offsetof(struct net, ipv4.sysctl_tcp_wmem),
2861 .sysctl_rmem_offset = offsetof(struct net, ipv4.sysctl_tcp_rmem),
2862 .max_header = MAX_TCP_HEADER,
2863 .obj_size = sizeof(struct tcp_sock),
2864 .slab_flags = SLAB_TYPESAFE_BY_RCU,
2865 .twsk_prot = &tcp_timewait_sock_ops,
2866 .rsk_prot = &tcp_request_sock_ops,
2867 .h.hashinfo = &tcp_hashinfo,
2868 .no_autobind = true,
2869 .diag_destroy = tcp_abort,
2870};
2871EXPORT_SYMBOL(tcp_prot);
2872
2873static void __net_exit tcp_sk_exit(struct net *net)
2874{
2875 int cpu;
2876
2877 if (net->ipv4.tcp_congestion_control)
2878 bpf_module_put(net->ipv4.tcp_congestion_control,
2879 net->ipv4.tcp_congestion_control->owner);
2880
2881 for_each_possible_cpu(cpu)
2882 inet_ctl_sock_destroy(*per_cpu_ptr(net->ipv4.tcp_sk, cpu));
2883 free_percpu(net->ipv4.tcp_sk);
2884}
2885
2886static int __net_init tcp_sk_init(struct net *net)
2887{
2888 int res, cpu, cnt;
2889
2890 net->ipv4.tcp_sk = alloc_percpu(struct sock *);
2891 if (!net->ipv4.tcp_sk)
2892 return -ENOMEM;
2893
2894 for_each_possible_cpu(cpu) {
2895 struct sock *sk;
2896
2897 res = inet_ctl_sock_create(&sk, PF_INET, SOCK_RAW,
2898 IPPROTO_TCP, net);
2899 if (res)
2900 goto fail;
2901 sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
2902
2903 /* Please enforce IP_DF and IPID==0 for RST and
2904 * ACK sent in SYN-RECV and TIME-WAIT state.
2905 */
2906 inet_sk(sk)->pmtudisc = IP_PMTUDISC_DO;
2907
2908 *per_cpu_ptr(net->ipv4.tcp_sk, cpu) = sk;
2909 }
2910
2911 net->ipv4.sysctl_tcp_ecn = 2;
2912 net->ipv4.sysctl_tcp_ecn_fallback = 1;
2913
2914 net->ipv4.sysctl_tcp_base_mss = TCP_BASE_MSS;
2915 net->ipv4.sysctl_tcp_min_snd_mss = TCP_MIN_SND_MSS;
2916 net->ipv4.sysctl_tcp_probe_threshold = TCP_PROBE_THRESHOLD;
2917 net->ipv4.sysctl_tcp_probe_interval = TCP_PROBE_INTERVAL;
2918 net->ipv4.sysctl_tcp_mtu_probe_floor = TCP_MIN_SND_MSS;
2919
2920 net->ipv4.sysctl_tcp_keepalive_time = TCP_KEEPALIVE_TIME;
2921 net->ipv4.sysctl_tcp_keepalive_probes = TCP_KEEPALIVE_PROBES;
2922 net->ipv4.sysctl_tcp_keepalive_intvl = TCP_KEEPALIVE_INTVL;
2923
2924 net->ipv4.sysctl_tcp_syn_retries = TCP_SYN_RETRIES;
2925 net->ipv4.sysctl_tcp_synack_retries = TCP_SYNACK_RETRIES;
2926 net->ipv4.sysctl_tcp_syncookies = 1;
2927 net->ipv4.sysctl_tcp_reordering = TCP_FASTRETRANS_THRESH;
2928 net->ipv4.sysctl_tcp_retries1 = TCP_RETR1;
2929 net->ipv4.sysctl_tcp_retries2 = TCP_RETR2;
2930 net->ipv4.sysctl_tcp_orphan_retries = 0;
2931 net->ipv4.sysctl_tcp_fin_timeout = TCP_FIN_TIMEOUT;
2932 net->ipv4.sysctl_tcp_notsent_lowat = UINT_MAX;
2933 net->ipv4.sysctl_tcp_tw_reuse = 2;
2934 net->ipv4.sysctl_tcp_no_ssthresh_metrics_save = 1;
2935
2936 cnt = tcp_hashinfo.ehash_mask + 1;
2937 net->ipv4.tcp_death_row.sysctl_max_tw_buckets = cnt / 2;
2938 net->ipv4.tcp_death_row.hashinfo = &tcp_hashinfo;
2939
2940 net->ipv4.sysctl_max_syn_backlog = max(128, cnt / 128);
2941 net->ipv4.sysctl_tcp_sack = 1;
2942 net->ipv4.sysctl_tcp_window_scaling = 1;
2943 net->ipv4.sysctl_tcp_timestamps = 1;
2944 net->ipv4.sysctl_tcp_early_retrans = 3;
2945 net->ipv4.sysctl_tcp_recovery = TCP_RACK_LOSS_DETECTION;
2946 net->ipv4.sysctl_tcp_slow_start_after_idle = 1; /* By default, RFC2861 behavior. */
2947 net->ipv4.sysctl_tcp_retrans_collapse = 1;
2948 net->ipv4.sysctl_tcp_max_reordering = 300;
2949 net->ipv4.sysctl_tcp_dsack = 1;
2950 net->ipv4.sysctl_tcp_app_win = 31;
2951 net->ipv4.sysctl_tcp_adv_win_scale = 1;
2952 net->ipv4.sysctl_tcp_frto = 2;
2953 net->ipv4.sysctl_tcp_moderate_rcvbuf = 1;
2954 /* This limits the percentage of the congestion window which we
2955 * will allow a single TSO frame to consume. Building TSO frames
2956 * which are too large can cause TCP streams to be bursty.
2957 */
2958 net->ipv4.sysctl_tcp_tso_win_divisor = 3;
2959 /* Default TSQ limit of 16 TSO segments */
2960 net->ipv4.sysctl_tcp_limit_output_bytes = 16 * 65536;
2961 /* rfc5961 challenge ack rate limiting */
2962 net->ipv4.sysctl_tcp_challenge_ack_limit = 1000;
2963 net->ipv4.sysctl_tcp_min_tso_segs = 2;
2964 net->ipv4.sysctl_tcp_min_rtt_wlen = 300;
2965 net->ipv4.sysctl_tcp_autocorking = 1;
2966 net->ipv4.sysctl_tcp_invalid_ratelimit = HZ/2;
2967 net->ipv4.sysctl_tcp_pacing_ss_ratio = 200;
2968 net->ipv4.sysctl_tcp_pacing_ca_ratio = 120;
2969 if (net != &init_net) {
2970 memcpy(net->ipv4.sysctl_tcp_rmem,
2971 init_net.ipv4.sysctl_tcp_rmem,
2972 sizeof(init_net.ipv4.sysctl_tcp_rmem));
2973 memcpy(net->ipv4.sysctl_tcp_wmem,
2974 init_net.ipv4.sysctl_tcp_wmem,
2975 sizeof(init_net.ipv4.sysctl_tcp_wmem));
2976 }
2977 net->ipv4.sysctl_tcp_comp_sack_delay_ns = NSEC_PER_MSEC;
2978 net->ipv4.sysctl_tcp_comp_sack_slack_ns = 100 * NSEC_PER_USEC;
2979 net->ipv4.sysctl_tcp_comp_sack_nr = 44;
2980 net->ipv4.sysctl_tcp_fastopen = TFO_CLIENT_ENABLE;
2981 spin_lock_init(&net->ipv4.tcp_fastopen_ctx_lock);
2982 net->ipv4.sysctl_tcp_fastopen_blackhole_timeout = 0;
2983 atomic_set(&net->ipv4.tfo_active_disable_times, 0);
2984
2985 /* Reno is always built in */
2986 if (!net_eq(net, &init_net) &&
2987 bpf_try_module_get(init_net.ipv4.tcp_congestion_control,
2988 init_net.ipv4.tcp_congestion_control->owner))
2989 net->ipv4.tcp_congestion_control = init_net.ipv4.tcp_congestion_control;
2990 else
2991 net->ipv4.tcp_congestion_control = &tcp_reno;
2992
2993 return 0;
2994fail:
2995 tcp_sk_exit(net);
2996
2997 return res;
2998}
2999
3000static void __net_exit tcp_sk_exit_batch(struct list_head *net_exit_list)
3001{
3002 struct net *net;
3003
3004 inet_twsk_purge(&tcp_hashinfo, AF_INET);
3005
3006 list_for_each_entry(net, net_exit_list, exit_list)
3007 tcp_fastopen_ctx_destroy(net);
3008}
3009
3010static struct pernet_operations __net_initdata tcp_sk_ops = {
3011 .init = tcp_sk_init,
3012 .exit = tcp_sk_exit,
3013 .exit_batch = tcp_sk_exit_batch,
3014};
3015
3016#if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS)
3017DEFINE_BPF_ITER_FUNC(tcp, struct bpf_iter_meta *meta,
3018 struct sock_common *sk_common, uid_t uid)
3019
3020static int bpf_iter_init_tcp(void *priv_data, struct bpf_iter_aux_info *aux)
3021{
3022 struct tcp_iter_state *st = priv_data;
3023 struct tcp_seq_afinfo *afinfo;
3024 int ret;
3025
3026 afinfo = kmalloc(sizeof(*afinfo), GFP_USER | __GFP_NOWARN);
3027 if (!afinfo)
3028 return -ENOMEM;
3029
3030 afinfo->family = AF_UNSPEC;
3031 st->bpf_seq_afinfo = afinfo;
3032 ret = bpf_iter_init_seq_net(priv_data, aux);
3033 if (ret)
3034 kfree(afinfo);
3035 return ret;
3036}
3037
3038static void bpf_iter_fini_tcp(void *priv_data)
3039{
3040 struct tcp_iter_state *st = priv_data;
3041
3042 kfree(st->bpf_seq_afinfo);
3043 bpf_iter_fini_seq_net(priv_data);
3044}
3045
3046static const struct bpf_iter_seq_info tcp_seq_info = {
3047 .seq_ops = &bpf_iter_tcp_seq_ops,
3048 .init_seq_private = bpf_iter_init_tcp,
3049 .fini_seq_private = bpf_iter_fini_tcp,
3050 .seq_priv_size = sizeof(struct tcp_iter_state),
3051};
3052
3053static struct bpf_iter_reg tcp_reg_info = {
3054 .target = "tcp",
3055 .ctx_arg_info_size = 1,
3056 .ctx_arg_info = {
3057 { offsetof(struct bpf_iter__tcp, sk_common),
3058 PTR_TO_BTF_ID_OR_NULL },
3059 },
3060 .seq_info = &tcp_seq_info,
3061};
3062
3063static void __init bpf_iter_register(void)
3064{
3065 tcp_reg_info.ctx_arg_info[0].btf_id = btf_sock_ids[BTF_SOCK_TYPE_SOCK_COMMON];
3066 if (bpf_iter_reg_target(&tcp_reg_info))
3067 pr_warn("Warning: could not register bpf iterator tcp\n");
3068}
3069
3070#endif
3071
3072void __init tcp_v4_init(void)
3073{
3074 if (register_pernet_subsys(&tcp_sk_ops))
3075 panic("Failed to create the TCP control socket.\n");
3076
3077#if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS)
3078 bpf_iter_register();
3079#endif
3080}
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#include <linux/sched.h>
61
62#include <net/net_namespace.h>
63#include <net/icmp.h>
64#include <net/inet_hashtables.h>
65#include <net/tcp.h>
66#include <net/transp_v6.h>
67#include <net/ipv6.h>
68#include <net/inet_common.h>
69#include <net/timewait_sock.h>
70#include <net/xfrm.h>
71#include <net/secure_seq.h>
72#include <net/busy_poll.h>
73
74#include <linux/inet.h>
75#include <linux/ipv6.h>
76#include <linux/stddef.h>
77#include <linux/proc_fs.h>
78#include <linux/seq_file.h>
79#include <linux/inetdevice.h>
80#include <linux/btf_ids.h>
81
82#include <crypto/hash.h>
83#include <linux/scatterlist.h>
84
85#include <trace/events/tcp.h>
86
87#ifdef CONFIG_TCP_MD5SIG
88static int tcp_v4_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key,
89 __be32 daddr, __be32 saddr, const struct tcphdr *th);
90#endif
91
92struct inet_hashinfo tcp_hashinfo;
93EXPORT_SYMBOL(tcp_hashinfo);
94
95static DEFINE_PER_CPU(struct sock *, ipv4_tcp_sk);
96
97static u32 tcp_v4_init_seq(const struct sk_buff *skb)
98{
99 return secure_tcp_seq(ip_hdr(skb)->daddr,
100 ip_hdr(skb)->saddr,
101 tcp_hdr(skb)->dest,
102 tcp_hdr(skb)->source);
103}
104
105static u32 tcp_v4_init_ts_off(const struct net *net, const struct sk_buff *skb)
106{
107 return secure_tcp_ts_off(net, ip_hdr(skb)->daddr, ip_hdr(skb)->saddr);
108}
109
110int tcp_twsk_unique(struct sock *sk, struct sock *sktw, void *twp)
111{
112 int reuse = READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_tw_reuse);
113 const struct inet_timewait_sock *tw = inet_twsk(sktw);
114 const struct tcp_timewait_sock *tcptw = tcp_twsk(sktw);
115 struct tcp_sock *tp = tcp_sk(sk);
116
117 if (reuse == 2) {
118 /* Still does not detect *everything* that goes through
119 * lo, since we require a loopback src or dst address
120 * or direct binding to 'lo' interface.
121 */
122 bool loopback = false;
123 if (tw->tw_bound_dev_if == LOOPBACK_IFINDEX)
124 loopback = true;
125#if IS_ENABLED(CONFIG_IPV6)
126 if (tw->tw_family == AF_INET6) {
127 if (ipv6_addr_loopback(&tw->tw_v6_daddr) ||
128 ipv6_addr_v4mapped_loopback(&tw->tw_v6_daddr) ||
129 ipv6_addr_loopback(&tw->tw_v6_rcv_saddr) ||
130 ipv6_addr_v4mapped_loopback(&tw->tw_v6_rcv_saddr))
131 loopback = true;
132 } else
133#endif
134 {
135 if (ipv4_is_loopback(tw->tw_daddr) ||
136 ipv4_is_loopback(tw->tw_rcv_saddr))
137 loopback = true;
138 }
139 if (!loopback)
140 reuse = 0;
141 }
142
143 /* With PAWS, it is safe from the viewpoint
144 of data integrity. Even without PAWS it is safe provided sequence
145 spaces do not overlap i.e. at data rates <= 80Mbit/sec.
146
147 Actually, the idea is close to VJ's one, only timestamp cache is
148 held not per host, but per port pair and TW bucket is used as state
149 holder.
150
151 If TW bucket has been already destroyed we fall back to VJ's scheme
152 and use initial timestamp retrieved from peer table.
153 */
154 if (tcptw->tw_ts_recent_stamp &&
155 (!twp || (reuse && time_after32(ktime_get_seconds(),
156 tcptw->tw_ts_recent_stamp)))) {
157 /* In case of repair and re-using TIME-WAIT sockets we still
158 * want to be sure that it is safe as above but honor the
159 * sequence numbers and time stamps set as part of the repair
160 * process.
161 *
162 * Without this check re-using a TIME-WAIT socket with TCP
163 * repair would accumulate a -1 on the repair assigned
164 * sequence number. The first time it is reused the sequence
165 * is -1, the second time -2, etc. This fixes that issue
166 * without appearing to create any others.
167 */
168 if (likely(!tp->repair)) {
169 u32 seq = tcptw->tw_snd_nxt + 65535 + 2;
170
171 if (!seq)
172 seq = 1;
173 WRITE_ONCE(tp->write_seq, seq);
174 tp->rx_opt.ts_recent = tcptw->tw_ts_recent;
175 tp->rx_opt.ts_recent_stamp = tcptw->tw_ts_recent_stamp;
176 }
177 sock_hold(sktw);
178 return 1;
179 }
180
181 return 0;
182}
183EXPORT_SYMBOL_GPL(tcp_twsk_unique);
184
185static int tcp_v4_pre_connect(struct sock *sk, struct sockaddr *uaddr,
186 int addr_len)
187{
188 /* This check is replicated from tcp_v4_connect() and intended to
189 * prevent BPF program called below from accessing bytes that are out
190 * of the bound specified by user in addr_len.
191 */
192 if (addr_len < sizeof(struct sockaddr_in))
193 return -EINVAL;
194
195 sock_owned_by_me(sk);
196
197 return BPF_CGROUP_RUN_PROG_INET4_CONNECT(sk, uaddr, &addr_len);
198}
199
200/* This will initiate an outgoing connection. */
201int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
202{
203 struct sockaddr_in *usin = (struct sockaddr_in *)uaddr;
204 struct inet_timewait_death_row *tcp_death_row;
205 struct inet_sock *inet = inet_sk(sk);
206 struct tcp_sock *tp = tcp_sk(sk);
207 struct ip_options_rcu *inet_opt;
208 struct net *net = sock_net(sk);
209 __be16 orig_sport, orig_dport;
210 __be32 daddr, nexthop;
211 struct flowi4 *fl4;
212 struct rtable *rt;
213 int err;
214
215 if (addr_len < sizeof(struct sockaddr_in))
216 return -EINVAL;
217
218 if (usin->sin_family != AF_INET)
219 return -EAFNOSUPPORT;
220
221 nexthop = daddr = usin->sin_addr.s_addr;
222 inet_opt = rcu_dereference_protected(inet->inet_opt,
223 lockdep_sock_is_held(sk));
224 if (inet_opt && inet_opt->opt.srr) {
225 if (!daddr)
226 return -EINVAL;
227 nexthop = inet_opt->opt.faddr;
228 }
229
230 orig_sport = inet->inet_sport;
231 orig_dport = usin->sin_port;
232 fl4 = &inet->cork.fl.u.ip4;
233 rt = ip_route_connect(fl4, nexthop, inet->inet_saddr,
234 sk->sk_bound_dev_if, IPPROTO_TCP, orig_sport,
235 orig_dport, sk);
236 if (IS_ERR(rt)) {
237 err = PTR_ERR(rt);
238 if (err == -ENETUNREACH)
239 IP_INC_STATS(net, IPSTATS_MIB_OUTNOROUTES);
240 return err;
241 }
242
243 if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) {
244 ip_rt_put(rt);
245 return -ENETUNREACH;
246 }
247
248 if (!inet_opt || !inet_opt->opt.srr)
249 daddr = fl4->daddr;
250
251 tcp_death_row = &sock_net(sk)->ipv4.tcp_death_row;
252
253 if (!inet->inet_saddr) {
254 err = inet_bhash2_update_saddr(sk, &fl4->saddr, AF_INET);
255 if (err) {
256 ip_rt_put(rt);
257 return err;
258 }
259 } else {
260 sk_rcv_saddr_set(sk, inet->inet_saddr);
261 }
262
263 if (tp->rx_opt.ts_recent_stamp && inet->inet_daddr != daddr) {
264 /* Reset inherited state */
265 tp->rx_opt.ts_recent = 0;
266 tp->rx_opt.ts_recent_stamp = 0;
267 if (likely(!tp->repair))
268 WRITE_ONCE(tp->write_seq, 0);
269 }
270
271 inet->inet_dport = usin->sin_port;
272 sk_daddr_set(sk, daddr);
273
274 inet_csk(sk)->icsk_ext_hdr_len = 0;
275 if (inet_opt)
276 inet_csk(sk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
277
278 tp->rx_opt.mss_clamp = TCP_MSS_DEFAULT;
279
280 /* Socket identity is still unknown (sport may be zero).
281 * However we set state to SYN-SENT and not releasing socket
282 * lock select source port, enter ourselves into the hash tables and
283 * complete initialization after this.
284 */
285 tcp_set_state(sk, TCP_SYN_SENT);
286 err = inet_hash_connect(tcp_death_row, sk);
287 if (err)
288 goto failure;
289
290 sk_set_txhash(sk);
291
292 rt = ip_route_newports(fl4, rt, orig_sport, orig_dport,
293 inet->inet_sport, inet->inet_dport, sk);
294 if (IS_ERR(rt)) {
295 err = PTR_ERR(rt);
296 rt = NULL;
297 goto failure;
298 }
299 tp->tcp_usec_ts = dst_tcp_usec_ts(&rt->dst);
300 /* OK, now commit destination to socket. */
301 sk->sk_gso_type = SKB_GSO_TCPV4;
302 sk_setup_caps(sk, &rt->dst);
303 rt = NULL;
304
305 if (likely(!tp->repair)) {
306 if (!tp->write_seq)
307 WRITE_ONCE(tp->write_seq,
308 secure_tcp_seq(inet->inet_saddr,
309 inet->inet_daddr,
310 inet->inet_sport,
311 usin->sin_port));
312 WRITE_ONCE(tp->tsoffset,
313 secure_tcp_ts_off(net, inet->inet_saddr,
314 inet->inet_daddr));
315 }
316
317 atomic_set(&inet->inet_id, get_random_u16());
318
319 if (tcp_fastopen_defer_connect(sk, &err))
320 return err;
321 if (err)
322 goto failure;
323
324 err = tcp_connect(sk);
325
326 if (err)
327 goto failure;
328
329 return 0;
330
331failure:
332 /*
333 * This unhashes the socket and releases the local port,
334 * if necessary.
335 */
336 tcp_set_state(sk, TCP_CLOSE);
337 inet_bhash2_reset_saddr(sk);
338 ip_rt_put(rt);
339 sk->sk_route_caps = 0;
340 inet->inet_dport = 0;
341 return err;
342}
343EXPORT_SYMBOL(tcp_v4_connect);
344
345/*
346 * This routine reacts to ICMP_FRAG_NEEDED mtu indications as defined in RFC1191.
347 * It can be called through tcp_release_cb() if socket was owned by user
348 * at the time tcp_v4_err() was called to handle ICMP message.
349 */
350void tcp_v4_mtu_reduced(struct sock *sk)
351{
352 struct inet_sock *inet = inet_sk(sk);
353 struct dst_entry *dst;
354 u32 mtu;
355
356 if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE))
357 return;
358 mtu = READ_ONCE(tcp_sk(sk)->mtu_info);
359 dst = inet_csk_update_pmtu(sk, mtu);
360 if (!dst)
361 return;
362
363 /* Something is about to be wrong... Remember soft error
364 * for the case, if this connection will not able to recover.
365 */
366 if (mtu < dst_mtu(dst) && ip_dont_fragment(sk, dst))
367 WRITE_ONCE(sk->sk_err_soft, EMSGSIZE);
368
369 mtu = dst_mtu(dst);
370
371 if (inet->pmtudisc != IP_PMTUDISC_DONT &&
372 ip_sk_accept_pmtu(sk) &&
373 inet_csk(sk)->icsk_pmtu_cookie > mtu) {
374 tcp_sync_mss(sk, mtu);
375
376 /* Resend the TCP packet because it's
377 * clear that the old packet has been
378 * dropped. This is the new "fast" path mtu
379 * discovery.
380 */
381 tcp_simple_retransmit(sk);
382 } /* else let the usual retransmit timer handle it */
383}
384EXPORT_SYMBOL(tcp_v4_mtu_reduced);
385
386static void do_redirect(struct sk_buff *skb, struct sock *sk)
387{
388 struct dst_entry *dst = __sk_dst_check(sk, 0);
389
390 if (dst)
391 dst->ops->redirect(dst, sk, skb);
392}
393
394
395/* handle ICMP messages on TCP_NEW_SYN_RECV request sockets */
396void tcp_req_err(struct sock *sk, u32 seq, bool abort)
397{
398 struct request_sock *req = inet_reqsk(sk);
399 struct net *net = sock_net(sk);
400
401 /* ICMPs are not backlogged, hence we cannot get
402 * an established socket here.
403 */
404 if (seq != tcp_rsk(req)->snt_isn) {
405 __NET_INC_STATS(net, LINUX_MIB_OUTOFWINDOWICMPS);
406 } else if (abort) {
407 /*
408 * Still in SYN_RECV, just remove it silently.
409 * There is no good way to pass the error to the newly
410 * created socket, and POSIX does not want network
411 * errors returned from accept().
412 */
413 inet_csk_reqsk_queue_drop(req->rsk_listener, req);
414 tcp_listendrop(req->rsk_listener);
415 }
416 reqsk_put(req);
417}
418EXPORT_SYMBOL(tcp_req_err);
419
420/* TCP-LD (RFC 6069) logic */
421void tcp_ld_RTO_revert(struct sock *sk, u32 seq)
422{
423 struct inet_connection_sock *icsk = inet_csk(sk);
424 struct tcp_sock *tp = tcp_sk(sk);
425 struct sk_buff *skb;
426 s32 remaining;
427 u32 delta_us;
428
429 if (sock_owned_by_user(sk))
430 return;
431
432 if (seq != tp->snd_una || !icsk->icsk_retransmits ||
433 !icsk->icsk_backoff)
434 return;
435
436 skb = tcp_rtx_queue_head(sk);
437 if (WARN_ON_ONCE(!skb))
438 return;
439
440 icsk->icsk_backoff--;
441 icsk->icsk_rto = tp->srtt_us ? __tcp_set_rto(tp) : TCP_TIMEOUT_INIT;
442 icsk->icsk_rto = inet_csk_rto_backoff(icsk, TCP_RTO_MAX);
443
444 tcp_mstamp_refresh(tp);
445 delta_us = (u32)(tp->tcp_mstamp - tcp_skb_timestamp_us(skb));
446 remaining = icsk->icsk_rto - usecs_to_jiffies(delta_us);
447
448 if (remaining > 0) {
449 inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
450 remaining, TCP_RTO_MAX);
451 } else {
452 /* RTO revert clocked out retransmission.
453 * Will retransmit now.
454 */
455 tcp_retransmit_timer(sk);
456 }
457}
458EXPORT_SYMBOL(tcp_ld_RTO_revert);
459
460/*
461 * This routine is called by the ICMP module when it gets some
462 * sort of error condition. If err < 0 then the socket should
463 * be closed and the error returned to the user. If err > 0
464 * it's just the icmp type << 8 | icmp code. After adjustment
465 * header points to the first 8 bytes of the tcp header. We need
466 * to find the appropriate port.
467 *
468 * The locking strategy used here is very "optimistic". When
469 * someone else accesses the socket the ICMP is just dropped
470 * and for some paths there is no check at all.
471 * A more general error queue to queue errors for later handling
472 * is probably better.
473 *
474 */
475
476int tcp_v4_err(struct sk_buff *skb, u32 info)
477{
478 const struct iphdr *iph = (const struct iphdr *)skb->data;
479 struct tcphdr *th = (struct tcphdr *)(skb->data + (iph->ihl << 2));
480 struct tcp_sock *tp;
481 const int type = icmp_hdr(skb)->type;
482 const int code = icmp_hdr(skb)->code;
483 struct sock *sk;
484 struct request_sock *fastopen;
485 u32 seq, snd_una;
486 int err;
487 struct net *net = dev_net(skb->dev);
488
489 sk = __inet_lookup_established(net, net->ipv4.tcp_death_row.hashinfo,
490 iph->daddr, th->dest, iph->saddr,
491 ntohs(th->source), inet_iif(skb), 0);
492 if (!sk) {
493 __ICMP_INC_STATS(net, ICMP_MIB_INERRORS);
494 return -ENOENT;
495 }
496 if (sk->sk_state == TCP_TIME_WAIT) {
497 /* To increase the counter of ignored icmps for TCP-AO */
498 tcp_ao_ignore_icmp(sk, AF_INET, type, code);
499 inet_twsk_put(inet_twsk(sk));
500 return 0;
501 }
502 seq = ntohl(th->seq);
503 if (sk->sk_state == TCP_NEW_SYN_RECV) {
504 tcp_req_err(sk, seq, type == ICMP_PARAMETERPROB ||
505 type == ICMP_TIME_EXCEEDED ||
506 (type == ICMP_DEST_UNREACH &&
507 (code == ICMP_NET_UNREACH ||
508 code == ICMP_HOST_UNREACH)));
509 return 0;
510 }
511
512 if (tcp_ao_ignore_icmp(sk, AF_INET, type, code)) {
513 sock_put(sk);
514 return 0;
515 }
516
517 bh_lock_sock(sk);
518 /* If too many ICMPs get dropped on busy
519 * servers this needs to be solved differently.
520 * We do take care of PMTU discovery (RFC1191) special case :
521 * we can receive locally generated ICMP messages while socket is held.
522 */
523 if (sock_owned_by_user(sk)) {
524 if (!(type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED))
525 __NET_INC_STATS(net, LINUX_MIB_LOCKDROPPEDICMPS);
526 }
527 if (sk->sk_state == TCP_CLOSE)
528 goto out;
529
530 if (static_branch_unlikely(&ip4_min_ttl)) {
531 /* min_ttl can be changed concurrently from do_ip_setsockopt() */
532 if (unlikely(iph->ttl < READ_ONCE(inet_sk(sk)->min_ttl))) {
533 __NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP);
534 goto out;
535 }
536 }
537
538 tp = tcp_sk(sk);
539 /* XXX (TFO) - tp->snd_una should be ISN (tcp_create_openreq_child() */
540 fastopen = rcu_dereference(tp->fastopen_rsk);
541 snd_una = fastopen ? tcp_rsk(fastopen)->snt_isn : tp->snd_una;
542 if (sk->sk_state != TCP_LISTEN &&
543 !between(seq, snd_una, tp->snd_nxt)) {
544 __NET_INC_STATS(net, LINUX_MIB_OUTOFWINDOWICMPS);
545 goto out;
546 }
547
548 switch (type) {
549 case ICMP_REDIRECT:
550 if (!sock_owned_by_user(sk))
551 do_redirect(skb, sk);
552 goto out;
553 case ICMP_SOURCE_QUENCH:
554 /* Just silently ignore these. */
555 goto out;
556 case ICMP_PARAMETERPROB:
557 err = EPROTO;
558 break;
559 case ICMP_DEST_UNREACH:
560 if (code > NR_ICMP_UNREACH)
561 goto out;
562
563 if (code == ICMP_FRAG_NEEDED) { /* PMTU discovery (RFC1191) */
564 /* We are not interested in TCP_LISTEN and open_requests
565 * (SYN-ACKs send out by Linux are always <576bytes so
566 * they should go through unfragmented).
567 */
568 if (sk->sk_state == TCP_LISTEN)
569 goto out;
570
571 WRITE_ONCE(tp->mtu_info, info);
572 if (!sock_owned_by_user(sk)) {
573 tcp_v4_mtu_reduced(sk);
574 } else {
575 if (!test_and_set_bit(TCP_MTU_REDUCED_DEFERRED, &sk->sk_tsq_flags))
576 sock_hold(sk);
577 }
578 goto out;
579 }
580
581 err = icmp_err_convert[code].errno;
582 /* check if this ICMP message allows revert of backoff.
583 * (see RFC 6069)
584 */
585 if (!fastopen &&
586 (code == ICMP_NET_UNREACH || code == ICMP_HOST_UNREACH))
587 tcp_ld_RTO_revert(sk, seq);
588 break;
589 case ICMP_TIME_EXCEEDED:
590 err = EHOSTUNREACH;
591 break;
592 default:
593 goto out;
594 }
595
596 switch (sk->sk_state) {
597 case TCP_SYN_SENT:
598 case TCP_SYN_RECV:
599 /* Only in fast or simultaneous open. If a fast open socket is
600 * already accepted it is treated as a connected one below.
601 */
602 if (fastopen && !fastopen->sk)
603 break;
604
605 ip_icmp_error(sk, skb, err, th->dest, info, (u8 *)th);
606
607 if (!sock_owned_by_user(sk)) {
608 WRITE_ONCE(sk->sk_err, err);
609
610 sk_error_report(sk);
611
612 tcp_done(sk);
613 } else {
614 WRITE_ONCE(sk->sk_err_soft, err);
615 }
616 goto out;
617 }
618
619 /* If we've already connected we will keep trying
620 * until we time out, or the user gives up.
621 *
622 * rfc1122 4.2.3.9 allows to consider as hard errors
623 * only PROTO_UNREACH and PORT_UNREACH (well, FRAG_FAILED too,
624 * but it is obsoleted by pmtu discovery).
625 *
626 * Note, that in modern internet, where routing is unreliable
627 * and in each dark corner broken firewalls sit, sending random
628 * errors ordered by their masters even this two messages finally lose
629 * their original sense (even Linux sends invalid PORT_UNREACHs)
630 *
631 * Now we are in compliance with RFCs.
632 * --ANK (980905)
633 */
634
635 if (!sock_owned_by_user(sk) &&
636 inet_test_bit(RECVERR, sk)) {
637 WRITE_ONCE(sk->sk_err, err);
638 sk_error_report(sk);
639 } else { /* Only an error on timeout */
640 WRITE_ONCE(sk->sk_err_soft, err);
641 }
642
643out:
644 bh_unlock_sock(sk);
645 sock_put(sk);
646 return 0;
647}
648
649void __tcp_v4_send_check(struct sk_buff *skb, __be32 saddr, __be32 daddr)
650{
651 struct tcphdr *th = tcp_hdr(skb);
652
653 th->check = ~tcp_v4_check(skb->len, saddr, daddr, 0);
654 skb->csum_start = skb_transport_header(skb) - skb->head;
655 skb->csum_offset = offsetof(struct tcphdr, check);
656}
657
658/* This routine computes an IPv4 TCP checksum. */
659void tcp_v4_send_check(struct sock *sk, struct sk_buff *skb)
660{
661 const struct inet_sock *inet = inet_sk(sk);
662
663 __tcp_v4_send_check(skb, inet->inet_saddr, inet->inet_daddr);
664}
665EXPORT_SYMBOL(tcp_v4_send_check);
666
667#define REPLY_OPTIONS_LEN (MAX_TCP_OPTION_SPACE / sizeof(__be32))
668
669static bool tcp_v4_ao_sign_reset(const struct sock *sk, struct sk_buff *skb,
670 const struct tcp_ao_hdr *aoh,
671 struct ip_reply_arg *arg, struct tcphdr *reply,
672 __be32 reply_options[REPLY_OPTIONS_LEN])
673{
674#ifdef CONFIG_TCP_AO
675 int sdif = tcp_v4_sdif(skb);
676 int dif = inet_iif(skb);
677 int l3index = sdif ? dif : 0;
678 bool allocated_traffic_key;
679 struct tcp_ao_key *key;
680 char *traffic_key;
681 bool drop = true;
682 u32 ao_sne = 0;
683 u8 keyid;
684
685 rcu_read_lock();
686 if (tcp_ao_prepare_reset(sk, skb, aoh, l3index, ntohl(reply->seq),
687 &key, &traffic_key, &allocated_traffic_key,
688 &keyid, &ao_sne))
689 goto out;
690
691 reply_options[0] = htonl((TCPOPT_AO << 24) | (tcp_ao_len(key) << 16) |
692 (aoh->rnext_keyid << 8) | keyid);
693 arg->iov[0].iov_len += tcp_ao_len_aligned(key);
694 reply->doff = arg->iov[0].iov_len / 4;
695
696 if (tcp_ao_hash_hdr(AF_INET, (char *)&reply_options[1],
697 key, traffic_key,
698 (union tcp_ao_addr *)&ip_hdr(skb)->saddr,
699 (union tcp_ao_addr *)&ip_hdr(skb)->daddr,
700 reply, ao_sne))
701 goto out;
702 drop = false;
703out:
704 rcu_read_unlock();
705 if (allocated_traffic_key)
706 kfree(traffic_key);
707 return drop;
708#else
709 return true;
710#endif
711}
712
713/*
714 * This routine will send an RST to the other tcp.
715 *
716 * Someone asks: why I NEVER use socket parameters (TOS, TTL etc.)
717 * for reset.
718 * Answer: if a packet caused RST, it is not for a socket
719 * existing in our system, if it is matched to a socket,
720 * it is just duplicate segment or bug in other side's TCP.
721 * So that we build reply only basing on parameters
722 * arrived with segment.
723 * Exception: precedence violation. We do not implement it in any case.
724 */
725
726static void tcp_v4_send_reset(const struct sock *sk, struct sk_buff *skb)
727{
728 const struct tcphdr *th = tcp_hdr(skb);
729 struct {
730 struct tcphdr th;
731 __be32 opt[REPLY_OPTIONS_LEN];
732 } rep;
733 const __u8 *md5_hash_location = NULL;
734 const struct tcp_ao_hdr *aoh;
735 struct ip_reply_arg arg;
736#ifdef CONFIG_TCP_MD5SIG
737 struct tcp_md5sig_key *key = NULL;
738 unsigned char newhash[16];
739 struct sock *sk1 = NULL;
740 int genhash;
741#endif
742 u64 transmit_time = 0;
743 struct sock *ctl_sk;
744 struct net *net;
745 u32 txhash = 0;
746
747 /* Never send a reset in response to a reset. */
748 if (th->rst)
749 return;
750
751 /* If sk not NULL, it means we did a successful lookup and incoming
752 * route had to be correct. prequeue might have dropped our dst.
753 */
754 if (!sk && skb_rtable(skb)->rt_type != RTN_LOCAL)
755 return;
756
757 /* Swap the send and the receive. */
758 memset(&rep, 0, sizeof(rep));
759 rep.th.dest = th->source;
760 rep.th.source = th->dest;
761 rep.th.doff = sizeof(struct tcphdr) / 4;
762 rep.th.rst = 1;
763
764 if (th->ack) {
765 rep.th.seq = th->ack_seq;
766 } else {
767 rep.th.ack = 1;
768 rep.th.ack_seq = htonl(ntohl(th->seq) + th->syn + th->fin +
769 skb->len - (th->doff << 2));
770 }
771
772 memset(&arg, 0, sizeof(arg));
773 arg.iov[0].iov_base = (unsigned char *)&rep;
774 arg.iov[0].iov_len = sizeof(rep.th);
775
776 net = sk ? sock_net(sk) : dev_net(skb_dst(skb)->dev);
777
778 /* Invalid TCP option size or twice included auth */
779 if (tcp_parse_auth_options(tcp_hdr(skb), &md5_hash_location, &aoh))
780 return;
781
782 if (aoh && tcp_v4_ao_sign_reset(sk, skb, aoh, &arg, &rep.th, rep.opt))
783 return;
784
785#ifdef CONFIG_TCP_MD5SIG
786 rcu_read_lock();
787 if (sk && sk_fullsock(sk)) {
788 const union tcp_md5_addr *addr;
789 int l3index;
790
791 /* sdif set, means packet ingressed via a device
792 * in an L3 domain and inet_iif is set to it.
793 */
794 l3index = tcp_v4_sdif(skb) ? inet_iif(skb) : 0;
795 addr = (union tcp_md5_addr *)&ip_hdr(skb)->saddr;
796 key = tcp_md5_do_lookup(sk, l3index, addr, AF_INET);
797 } else if (md5_hash_location) {
798 const union tcp_md5_addr *addr;
799 int sdif = tcp_v4_sdif(skb);
800 int dif = inet_iif(skb);
801 int l3index;
802
803 /*
804 * active side is lost. Try to find listening socket through
805 * source port, and then find md5 key through listening socket.
806 * we are not loose security here:
807 * Incoming packet is checked with md5 hash with finding key,
808 * no RST generated if md5 hash doesn't match.
809 */
810 sk1 = __inet_lookup_listener(net, net->ipv4.tcp_death_row.hashinfo,
811 NULL, 0, ip_hdr(skb)->saddr,
812 th->source, ip_hdr(skb)->daddr,
813 ntohs(th->source), dif, sdif);
814 /* don't send rst if it can't find key */
815 if (!sk1)
816 goto out;
817
818 /* sdif set, means packet ingressed via a device
819 * in an L3 domain and dif is set to it.
820 */
821 l3index = sdif ? dif : 0;
822 addr = (union tcp_md5_addr *)&ip_hdr(skb)->saddr;
823 key = tcp_md5_do_lookup(sk1, l3index, addr, AF_INET);
824 if (!key)
825 goto out;
826
827
828 genhash = tcp_v4_md5_hash_skb(newhash, key, NULL, skb);
829 if (genhash || memcmp(md5_hash_location, newhash, 16) != 0)
830 goto out;
831
832 }
833
834 if (key) {
835 rep.opt[0] = htonl((TCPOPT_NOP << 24) |
836 (TCPOPT_NOP << 16) |
837 (TCPOPT_MD5SIG << 8) |
838 TCPOLEN_MD5SIG);
839 /* Update length and the length the header thinks exists */
840 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED;
841 rep.th.doff = arg.iov[0].iov_len / 4;
842
843 tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[1],
844 key, ip_hdr(skb)->saddr,
845 ip_hdr(skb)->daddr, &rep.th);
846 }
847#endif
848 /* Can't co-exist with TCPMD5, hence check rep.opt[0] */
849 if (rep.opt[0] == 0) {
850 __be32 mrst = mptcp_reset_option(skb);
851
852 if (mrst) {
853 rep.opt[0] = mrst;
854 arg.iov[0].iov_len += sizeof(mrst);
855 rep.th.doff = arg.iov[0].iov_len / 4;
856 }
857 }
858
859 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
860 ip_hdr(skb)->saddr, /* XXX */
861 arg.iov[0].iov_len, IPPROTO_TCP, 0);
862 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
863 arg.flags = (sk && inet_sk_transparent(sk)) ? IP_REPLY_ARG_NOSRCCHECK : 0;
864
865 /* When socket is gone, all binding information is lost.
866 * routing might fail in this case. No choice here, if we choose to force
867 * input interface, we will misroute in case of asymmetric route.
868 */
869 if (sk) {
870 arg.bound_dev_if = sk->sk_bound_dev_if;
871 if (sk_fullsock(sk))
872 trace_tcp_send_reset(sk, skb);
873 }
874
875 BUILD_BUG_ON(offsetof(struct sock, sk_bound_dev_if) !=
876 offsetof(struct inet_timewait_sock, tw_bound_dev_if));
877
878 arg.tos = ip_hdr(skb)->tos;
879 arg.uid = sock_net_uid(net, sk && sk_fullsock(sk) ? sk : NULL);
880 local_bh_disable();
881 ctl_sk = this_cpu_read(ipv4_tcp_sk);
882 sock_net_set(ctl_sk, net);
883 if (sk) {
884 ctl_sk->sk_mark = (sk->sk_state == TCP_TIME_WAIT) ?
885 inet_twsk(sk)->tw_mark : sk->sk_mark;
886 ctl_sk->sk_priority = (sk->sk_state == TCP_TIME_WAIT) ?
887 inet_twsk(sk)->tw_priority : READ_ONCE(sk->sk_priority);
888 transmit_time = tcp_transmit_time(sk);
889 xfrm_sk_clone_policy(ctl_sk, sk);
890 txhash = (sk->sk_state == TCP_TIME_WAIT) ?
891 inet_twsk(sk)->tw_txhash : sk->sk_txhash;
892 } else {
893 ctl_sk->sk_mark = 0;
894 ctl_sk->sk_priority = 0;
895 }
896 ip_send_unicast_reply(ctl_sk,
897 skb, &TCP_SKB_CB(skb)->header.h4.opt,
898 ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
899 &arg, arg.iov[0].iov_len,
900 transmit_time, txhash);
901
902 xfrm_sk_free_policy(ctl_sk);
903 sock_net_set(ctl_sk, &init_net);
904 __TCP_INC_STATS(net, TCP_MIB_OUTSEGS);
905 __TCP_INC_STATS(net, TCP_MIB_OUTRSTS);
906 local_bh_enable();
907
908#ifdef CONFIG_TCP_MD5SIG
909out:
910 rcu_read_unlock();
911#endif
912}
913
914/* The code following below sending ACKs in SYN-RECV and TIME-WAIT states
915 outside socket context is ugly, certainly. What can I do?
916 */
917
918static void tcp_v4_send_ack(const struct sock *sk,
919 struct sk_buff *skb, u32 seq, u32 ack,
920 u32 win, u32 tsval, u32 tsecr, int oif,
921 struct tcp_key *key,
922 int reply_flags, u8 tos, u32 txhash)
923{
924 const struct tcphdr *th = tcp_hdr(skb);
925 struct {
926 struct tcphdr th;
927 __be32 opt[(MAX_TCP_OPTION_SPACE >> 2)];
928 } rep;
929 struct net *net = sock_net(sk);
930 struct ip_reply_arg arg;
931 struct sock *ctl_sk;
932 u64 transmit_time;
933
934 memset(&rep.th, 0, sizeof(struct tcphdr));
935 memset(&arg, 0, sizeof(arg));
936
937 arg.iov[0].iov_base = (unsigned char *)&rep;
938 arg.iov[0].iov_len = sizeof(rep.th);
939 if (tsecr) {
940 rep.opt[0] = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
941 (TCPOPT_TIMESTAMP << 8) |
942 TCPOLEN_TIMESTAMP);
943 rep.opt[1] = htonl(tsval);
944 rep.opt[2] = htonl(tsecr);
945 arg.iov[0].iov_len += TCPOLEN_TSTAMP_ALIGNED;
946 }
947
948 /* Swap the send and the receive. */
949 rep.th.dest = th->source;
950 rep.th.source = th->dest;
951 rep.th.doff = arg.iov[0].iov_len / 4;
952 rep.th.seq = htonl(seq);
953 rep.th.ack_seq = htonl(ack);
954 rep.th.ack = 1;
955 rep.th.window = htons(win);
956
957#ifdef CONFIG_TCP_MD5SIG
958 if (tcp_key_is_md5(key)) {
959 int offset = (tsecr) ? 3 : 0;
960
961 rep.opt[offset++] = htonl((TCPOPT_NOP << 24) |
962 (TCPOPT_NOP << 16) |
963 (TCPOPT_MD5SIG << 8) |
964 TCPOLEN_MD5SIG);
965 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED;
966 rep.th.doff = arg.iov[0].iov_len/4;
967
968 tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[offset],
969 key->md5_key, ip_hdr(skb)->saddr,
970 ip_hdr(skb)->daddr, &rep.th);
971 }
972#endif
973#ifdef CONFIG_TCP_AO
974 if (tcp_key_is_ao(key)) {
975 int offset = (tsecr) ? 3 : 0;
976
977 rep.opt[offset++] = htonl((TCPOPT_AO << 24) |
978 (tcp_ao_len(key->ao_key) << 16) |
979 (key->ao_key->sndid << 8) |
980 key->rcv_next);
981 arg.iov[0].iov_len += tcp_ao_len_aligned(key->ao_key);
982 rep.th.doff = arg.iov[0].iov_len / 4;
983
984 tcp_ao_hash_hdr(AF_INET, (char *)&rep.opt[offset],
985 key->ao_key, key->traffic_key,
986 (union tcp_ao_addr *)&ip_hdr(skb)->saddr,
987 (union tcp_ao_addr *)&ip_hdr(skb)->daddr,
988 &rep.th, key->sne);
989 }
990#endif
991 arg.flags = reply_flags;
992 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
993 ip_hdr(skb)->saddr, /* XXX */
994 arg.iov[0].iov_len, IPPROTO_TCP, 0);
995 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
996 if (oif)
997 arg.bound_dev_if = oif;
998 arg.tos = tos;
999 arg.uid = sock_net_uid(net, sk_fullsock(sk) ? sk : NULL);
1000 local_bh_disable();
1001 ctl_sk = this_cpu_read(ipv4_tcp_sk);
1002 sock_net_set(ctl_sk, net);
1003 ctl_sk->sk_mark = (sk->sk_state == TCP_TIME_WAIT) ?
1004 inet_twsk(sk)->tw_mark : READ_ONCE(sk->sk_mark);
1005 ctl_sk->sk_priority = (sk->sk_state == TCP_TIME_WAIT) ?
1006 inet_twsk(sk)->tw_priority : READ_ONCE(sk->sk_priority);
1007 transmit_time = tcp_transmit_time(sk);
1008 ip_send_unicast_reply(ctl_sk,
1009 skb, &TCP_SKB_CB(skb)->header.h4.opt,
1010 ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
1011 &arg, arg.iov[0].iov_len,
1012 transmit_time, txhash);
1013
1014 sock_net_set(ctl_sk, &init_net);
1015 __TCP_INC_STATS(net, TCP_MIB_OUTSEGS);
1016 local_bh_enable();
1017}
1018
1019static void tcp_v4_timewait_ack(struct sock *sk, struct sk_buff *skb)
1020{
1021 struct inet_timewait_sock *tw = inet_twsk(sk);
1022 struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
1023 struct tcp_key key = {};
1024#ifdef CONFIG_TCP_AO
1025 struct tcp_ao_info *ao_info;
1026
1027 if (static_branch_unlikely(&tcp_ao_needed.key)) {
1028 /* FIXME: the segment to-be-acked is not verified yet */
1029 ao_info = rcu_dereference(tcptw->ao_info);
1030 if (ao_info) {
1031 const struct tcp_ao_hdr *aoh;
1032
1033 if (tcp_parse_auth_options(tcp_hdr(skb), NULL, &aoh)) {
1034 inet_twsk_put(tw);
1035 return;
1036 }
1037
1038 if (aoh)
1039 key.ao_key = tcp_ao_established_key(ao_info, aoh->rnext_keyid, -1);
1040 }
1041 }
1042 if (key.ao_key) {
1043 struct tcp_ao_key *rnext_key;
1044
1045 key.traffic_key = snd_other_key(key.ao_key);
1046 key.sne = READ_ONCE(ao_info->snd_sne);
1047 rnext_key = READ_ONCE(ao_info->rnext_key);
1048 key.rcv_next = rnext_key->rcvid;
1049 key.type = TCP_KEY_AO;
1050#else
1051 if (0) {
1052#endif
1053#ifdef CONFIG_TCP_MD5SIG
1054 } else if (static_branch_unlikely(&tcp_md5_needed.key)) {
1055 key.md5_key = tcp_twsk_md5_key(tcptw);
1056 if (key.md5_key)
1057 key.type = TCP_KEY_MD5;
1058#endif
1059 }
1060
1061 tcp_v4_send_ack(sk, skb,
1062 tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
1063 tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
1064 tcp_tw_tsval(tcptw),
1065 tcptw->tw_ts_recent,
1066 tw->tw_bound_dev_if, &key,
1067 tw->tw_transparent ? IP_REPLY_ARG_NOSRCCHECK : 0,
1068 tw->tw_tos,
1069 tw->tw_txhash);
1070
1071 inet_twsk_put(tw);
1072}
1073
1074static void tcp_v4_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb,
1075 struct request_sock *req)
1076{
1077 struct tcp_key key = {};
1078
1079 /* sk->sk_state == TCP_LISTEN -> for regular TCP_SYN_RECV
1080 * sk->sk_state == TCP_SYN_RECV -> for Fast Open.
1081 */
1082 u32 seq = (sk->sk_state == TCP_LISTEN) ? tcp_rsk(req)->snt_isn + 1 :
1083 tcp_sk(sk)->snd_nxt;
1084
1085#ifdef CONFIG_TCP_AO
1086 if (static_branch_unlikely(&tcp_ao_needed.key) &&
1087 tcp_rsk_used_ao(req)) {
1088 const union tcp_md5_addr *addr;
1089 const struct tcp_ao_hdr *aoh;
1090 int l3index;
1091
1092 /* Invalid TCP option size or twice included auth */
1093 if (tcp_parse_auth_options(tcp_hdr(skb), NULL, &aoh))
1094 return;
1095 if (!aoh)
1096 return;
1097
1098 addr = (union tcp_md5_addr *)&ip_hdr(skb)->saddr;
1099 l3index = tcp_v4_sdif(skb) ? inet_iif(skb) : 0;
1100 key.ao_key = tcp_ao_do_lookup(sk, l3index, addr, AF_INET,
1101 aoh->rnext_keyid, -1);
1102 if (unlikely(!key.ao_key)) {
1103 /* Send ACK with any matching MKT for the peer */
1104 key.ao_key = tcp_ao_do_lookup(sk, l3index, addr, AF_INET, -1, -1);
1105 /* Matching key disappeared (user removed the key?)
1106 * let the handshake timeout.
1107 */
1108 if (!key.ao_key) {
1109 net_info_ratelimited("TCP-AO key for (%pI4, %d)->(%pI4, %d) suddenly disappeared, won't ACK new connection\n",
1110 addr,
1111 ntohs(tcp_hdr(skb)->source),
1112 &ip_hdr(skb)->daddr,
1113 ntohs(tcp_hdr(skb)->dest));
1114 return;
1115 }
1116 }
1117 key.traffic_key = kmalloc(tcp_ao_digest_size(key.ao_key), GFP_ATOMIC);
1118 if (!key.traffic_key)
1119 return;
1120
1121 key.type = TCP_KEY_AO;
1122 key.rcv_next = aoh->keyid;
1123 tcp_v4_ao_calc_key_rsk(key.ao_key, key.traffic_key, req);
1124#else
1125 if (0) {
1126#endif
1127#ifdef CONFIG_TCP_MD5SIG
1128 } else if (static_branch_unlikely(&tcp_md5_needed.key)) {
1129 const union tcp_md5_addr *addr;
1130 int l3index;
1131
1132 addr = (union tcp_md5_addr *)&ip_hdr(skb)->saddr;
1133 l3index = tcp_v4_sdif(skb) ? inet_iif(skb) : 0;
1134 key.md5_key = tcp_md5_do_lookup(sk, l3index, addr, AF_INET);
1135 if (key.md5_key)
1136 key.type = TCP_KEY_MD5;
1137#endif
1138 }
1139
1140 /* RFC 7323 2.3
1141 * The window field (SEG.WND) of every outgoing segment, with the
1142 * exception of <SYN> segments, MUST be right-shifted by
1143 * Rcv.Wind.Shift bits:
1144 */
1145 tcp_v4_send_ack(sk, skb, seq,
1146 tcp_rsk(req)->rcv_nxt,
1147 req->rsk_rcv_wnd >> inet_rsk(req)->rcv_wscale,
1148 tcp_rsk_tsval(tcp_rsk(req)),
1149 READ_ONCE(req->ts_recent),
1150 0, &key,
1151 inet_rsk(req)->no_srccheck ? IP_REPLY_ARG_NOSRCCHECK : 0,
1152 ip_hdr(skb)->tos,
1153 READ_ONCE(tcp_rsk(req)->txhash));
1154 if (tcp_key_is_ao(&key))
1155 kfree(key.traffic_key);
1156}
1157
1158/*
1159 * Send a SYN-ACK after having received a SYN.
1160 * This still operates on a request_sock only, not on a big
1161 * socket.
1162 */
1163static int tcp_v4_send_synack(const struct sock *sk, struct dst_entry *dst,
1164 struct flowi *fl,
1165 struct request_sock *req,
1166 struct tcp_fastopen_cookie *foc,
1167 enum tcp_synack_type synack_type,
1168 struct sk_buff *syn_skb)
1169{
1170 const struct inet_request_sock *ireq = inet_rsk(req);
1171 struct flowi4 fl4;
1172 int err = -1;
1173 struct sk_buff *skb;
1174 u8 tos;
1175
1176 /* First, grab a route. */
1177 if (!dst && (dst = inet_csk_route_req(sk, &fl4, req)) == NULL)
1178 return -1;
1179
1180 skb = tcp_make_synack(sk, dst, req, foc, synack_type, syn_skb);
1181
1182 if (skb) {
1183 __tcp_v4_send_check(skb, ireq->ir_loc_addr, ireq->ir_rmt_addr);
1184
1185 tos = READ_ONCE(inet_sk(sk)->tos);
1186
1187 if (READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_reflect_tos))
1188 tos = (tcp_rsk(req)->syn_tos & ~INET_ECN_MASK) |
1189 (tos & INET_ECN_MASK);
1190
1191 if (!INET_ECN_is_capable(tos) &&
1192 tcp_bpf_ca_needs_ecn((struct sock *)req))
1193 tos |= INET_ECN_ECT_0;
1194
1195 rcu_read_lock();
1196 err = ip_build_and_send_pkt(skb, sk, ireq->ir_loc_addr,
1197 ireq->ir_rmt_addr,
1198 rcu_dereference(ireq->ireq_opt),
1199 tos);
1200 rcu_read_unlock();
1201 err = net_xmit_eval(err);
1202 }
1203
1204 return err;
1205}
1206
1207/*
1208 * IPv4 request_sock destructor.
1209 */
1210static void tcp_v4_reqsk_destructor(struct request_sock *req)
1211{
1212 kfree(rcu_dereference_protected(inet_rsk(req)->ireq_opt, 1));
1213}
1214
1215#ifdef CONFIG_TCP_MD5SIG
1216/*
1217 * RFC2385 MD5 checksumming requires a mapping of
1218 * IP address->MD5 Key.
1219 * We need to maintain these in the sk structure.
1220 */
1221
1222DEFINE_STATIC_KEY_DEFERRED_FALSE(tcp_md5_needed, HZ);
1223EXPORT_SYMBOL(tcp_md5_needed);
1224
1225static bool better_md5_match(struct tcp_md5sig_key *old, struct tcp_md5sig_key *new)
1226{
1227 if (!old)
1228 return true;
1229
1230 /* l3index always overrides non-l3index */
1231 if (old->l3index && new->l3index == 0)
1232 return false;
1233 if (old->l3index == 0 && new->l3index)
1234 return true;
1235
1236 return old->prefixlen < new->prefixlen;
1237}
1238
1239/* Find the Key structure for an address. */
1240struct tcp_md5sig_key *__tcp_md5_do_lookup(const struct sock *sk, int l3index,
1241 const union tcp_md5_addr *addr,
1242 int family, bool any_l3index)
1243{
1244 const struct tcp_sock *tp = tcp_sk(sk);
1245 struct tcp_md5sig_key *key;
1246 const struct tcp_md5sig_info *md5sig;
1247 __be32 mask;
1248 struct tcp_md5sig_key *best_match = NULL;
1249 bool match;
1250
1251 /* caller either holds rcu_read_lock() or socket lock */
1252 md5sig = rcu_dereference_check(tp->md5sig_info,
1253 lockdep_sock_is_held(sk));
1254 if (!md5sig)
1255 return NULL;
1256
1257 hlist_for_each_entry_rcu(key, &md5sig->head, node,
1258 lockdep_sock_is_held(sk)) {
1259 if (key->family != family)
1260 continue;
1261 if (!any_l3index && key->flags & TCP_MD5SIG_FLAG_IFINDEX &&
1262 key->l3index != l3index)
1263 continue;
1264 if (family == AF_INET) {
1265 mask = inet_make_mask(key->prefixlen);
1266 match = (key->addr.a4.s_addr & mask) ==
1267 (addr->a4.s_addr & mask);
1268#if IS_ENABLED(CONFIG_IPV6)
1269 } else if (family == AF_INET6) {
1270 match = ipv6_prefix_equal(&key->addr.a6, &addr->a6,
1271 key->prefixlen);
1272#endif
1273 } else {
1274 match = false;
1275 }
1276
1277 if (match && better_md5_match(best_match, key))
1278 best_match = key;
1279 }
1280 return best_match;
1281}
1282EXPORT_SYMBOL(__tcp_md5_do_lookup);
1283
1284static struct tcp_md5sig_key *tcp_md5_do_lookup_exact(const struct sock *sk,
1285 const union tcp_md5_addr *addr,
1286 int family, u8 prefixlen,
1287 int l3index, u8 flags)
1288{
1289 const struct tcp_sock *tp = tcp_sk(sk);
1290 struct tcp_md5sig_key *key;
1291 unsigned int size = sizeof(struct in_addr);
1292 const struct tcp_md5sig_info *md5sig;
1293
1294 /* caller either holds rcu_read_lock() or socket lock */
1295 md5sig = rcu_dereference_check(tp->md5sig_info,
1296 lockdep_sock_is_held(sk));
1297 if (!md5sig)
1298 return NULL;
1299#if IS_ENABLED(CONFIG_IPV6)
1300 if (family == AF_INET6)
1301 size = sizeof(struct in6_addr);
1302#endif
1303 hlist_for_each_entry_rcu(key, &md5sig->head, node,
1304 lockdep_sock_is_held(sk)) {
1305 if (key->family != family)
1306 continue;
1307 if ((key->flags & TCP_MD5SIG_FLAG_IFINDEX) != (flags & TCP_MD5SIG_FLAG_IFINDEX))
1308 continue;
1309 if (key->l3index != l3index)
1310 continue;
1311 if (!memcmp(&key->addr, addr, size) &&
1312 key->prefixlen == prefixlen)
1313 return key;
1314 }
1315 return NULL;
1316}
1317
1318struct tcp_md5sig_key *tcp_v4_md5_lookup(const struct sock *sk,
1319 const struct sock *addr_sk)
1320{
1321 const union tcp_md5_addr *addr;
1322 int l3index;
1323
1324 l3index = l3mdev_master_ifindex_by_index(sock_net(sk),
1325 addr_sk->sk_bound_dev_if);
1326 addr = (const union tcp_md5_addr *)&addr_sk->sk_daddr;
1327 return tcp_md5_do_lookup(sk, l3index, addr, AF_INET);
1328}
1329EXPORT_SYMBOL(tcp_v4_md5_lookup);
1330
1331static int tcp_md5sig_info_add(struct sock *sk, gfp_t gfp)
1332{
1333 struct tcp_sock *tp = tcp_sk(sk);
1334 struct tcp_md5sig_info *md5sig;
1335
1336 md5sig = kmalloc(sizeof(*md5sig), gfp);
1337 if (!md5sig)
1338 return -ENOMEM;
1339
1340 sk_gso_disable(sk);
1341 INIT_HLIST_HEAD(&md5sig->head);
1342 rcu_assign_pointer(tp->md5sig_info, md5sig);
1343 return 0;
1344}
1345
1346/* This can be called on a newly created socket, from other files */
1347static int __tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr,
1348 int family, u8 prefixlen, int l3index, u8 flags,
1349 const u8 *newkey, u8 newkeylen, gfp_t gfp)
1350{
1351 /* Add Key to the list */
1352 struct tcp_md5sig_key *key;
1353 struct tcp_sock *tp = tcp_sk(sk);
1354 struct tcp_md5sig_info *md5sig;
1355
1356 key = tcp_md5_do_lookup_exact(sk, addr, family, prefixlen, l3index, flags);
1357 if (key) {
1358 /* Pre-existing entry - just update that one.
1359 * Note that the key might be used concurrently.
1360 * data_race() is telling kcsan that we do not care of
1361 * key mismatches, since changing MD5 key on live flows
1362 * can lead to packet drops.
1363 */
1364 data_race(memcpy(key->key, newkey, newkeylen));
1365
1366 /* Pairs with READ_ONCE() in tcp_md5_hash_key().
1367 * Also note that a reader could catch new key->keylen value
1368 * but old key->key[], this is the reason we use __GFP_ZERO
1369 * at sock_kmalloc() time below these lines.
1370 */
1371 WRITE_ONCE(key->keylen, newkeylen);
1372
1373 return 0;
1374 }
1375
1376 md5sig = rcu_dereference_protected(tp->md5sig_info,
1377 lockdep_sock_is_held(sk));
1378
1379 key = sock_kmalloc(sk, sizeof(*key), gfp | __GFP_ZERO);
1380 if (!key)
1381 return -ENOMEM;
1382
1383 memcpy(key->key, newkey, newkeylen);
1384 key->keylen = newkeylen;
1385 key->family = family;
1386 key->prefixlen = prefixlen;
1387 key->l3index = l3index;
1388 key->flags = flags;
1389 memcpy(&key->addr, addr,
1390 (IS_ENABLED(CONFIG_IPV6) && family == AF_INET6) ? sizeof(struct in6_addr) :
1391 sizeof(struct in_addr));
1392 hlist_add_head_rcu(&key->node, &md5sig->head);
1393 return 0;
1394}
1395
1396int tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr,
1397 int family, u8 prefixlen, int l3index, u8 flags,
1398 const u8 *newkey, u8 newkeylen)
1399{
1400 struct tcp_sock *tp = tcp_sk(sk);
1401
1402 if (!rcu_dereference_protected(tp->md5sig_info, lockdep_sock_is_held(sk))) {
1403 if (tcp_md5_alloc_sigpool())
1404 return -ENOMEM;
1405
1406 if (tcp_md5sig_info_add(sk, GFP_KERNEL)) {
1407 tcp_md5_release_sigpool();
1408 return -ENOMEM;
1409 }
1410
1411 if (!static_branch_inc(&tcp_md5_needed.key)) {
1412 struct tcp_md5sig_info *md5sig;
1413
1414 md5sig = rcu_dereference_protected(tp->md5sig_info, lockdep_sock_is_held(sk));
1415 rcu_assign_pointer(tp->md5sig_info, NULL);
1416 kfree_rcu(md5sig, rcu);
1417 tcp_md5_release_sigpool();
1418 return -EUSERS;
1419 }
1420 }
1421
1422 return __tcp_md5_do_add(sk, addr, family, prefixlen, l3index, flags,
1423 newkey, newkeylen, GFP_KERNEL);
1424}
1425EXPORT_SYMBOL(tcp_md5_do_add);
1426
1427int tcp_md5_key_copy(struct sock *sk, const union tcp_md5_addr *addr,
1428 int family, u8 prefixlen, int l3index,
1429 struct tcp_md5sig_key *key)
1430{
1431 struct tcp_sock *tp = tcp_sk(sk);
1432
1433 if (!rcu_dereference_protected(tp->md5sig_info, lockdep_sock_is_held(sk))) {
1434 tcp_md5_add_sigpool();
1435
1436 if (tcp_md5sig_info_add(sk, sk_gfp_mask(sk, GFP_ATOMIC))) {
1437 tcp_md5_release_sigpool();
1438 return -ENOMEM;
1439 }
1440
1441 if (!static_key_fast_inc_not_disabled(&tcp_md5_needed.key.key)) {
1442 struct tcp_md5sig_info *md5sig;
1443
1444 md5sig = rcu_dereference_protected(tp->md5sig_info, lockdep_sock_is_held(sk));
1445 net_warn_ratelimited("Too many TCP-MD5 keys in the system\n");
1446 rcu_assign_pointer(tp->md5sig_info, NULL);
1447 kfree_rcu(md5sig, rcu);
1448 tcp_md5_release_sigpool();
1449 return -EUSERS;
1450 }
1451 }
1452
1453 return __tcp_md5_do_add(sk, addr, family, prefixlen, l3index,
1454 key->flags, key->key, key->keylen,
1455 sk_gfp_mask(sk, GFP_ATOMIC));
1456}
1457EXPORT_SYMBOL(tcp_md5_key_copy);
1458
1459int tcp_md5_do_del(struct sock *sk, const union tcp_md5_addr *addr, int family,
1460 u8 prefixlen, int l3index, u8 flags)
1461{
1462 struct tcp_md5sig_key *key;
1463
1464 key = tcp_md5_do_lookup_exact(sk, addr, family, prefixlen, l3index, flags);
1465 if (!key)
1466 return -ENOENT;
1467 hlist_del_rcu(&key->node);
1468 atomic_sub(sizeof(*key), &sk->sk_omem_alloc);
1469 kfree_rcu(key, rcu);
1470 return 0;
1471}
1472EXPORT_SYMBOL(tcp_md5_do_del);
1473
1474void tcp_clear_md5_list(struct sock *sk)
1475{
1476 struct tcp_sock *tp = tcp_sk(sk);
1477 struct tcp_md5sig_key *key;
1478 struct hlist_node *n;
1479 struct tcp_md5sig_info *md5sig;
1480
1481 md5sig = rcu_dereference_protected(tp->md5sig_info, 1);
1482
1483 hlist_for_each_entry_safe(key, n, &md5sig->head, node) {
1484 hlist_del_rcu(&key->node);
1485 atomic_sub(sizeof(*key), &sk->sk_omem_alloc);
1486 kfree_rcu(key, rcu);
1487 }
1488}
1489
1490static int tcp_v4_parse_md5_keys(struct sock *sk, int optname,
1491 sockptr_t optval, int optlen)
1492{
1493 struct tcp_md5sig cmd;
1494 struct sockaddr_in *sin = (struct sockaddr_in *)&cmd.tcpm_addr;
1495 const union tcp_md5_addr *addr;
1496 u8 prefixlen = 32;
1497 int l3index = 0;
1498 bool l3flag;
1499 u8 flags;
1500
1501 if (optlen < sizeof(cmd))
1502 return -EINVAL;
1503
1504 if (copy_from_sockptr(&cmd, optval, sizeof(cmd)))
1505 return -EFAULT;
1506
1507 if (sin->sin_family != AF_INET)
1508 return -EINVAL;
1509
1510 flags = cmd.tcpm_flags & TCP_MD5SIG_FLAG_IFINDEX;
1511 l3flag = cmd.tcpm_flags & TCP_MD5SIG_FLAG_IFINDEX;
1512
1513 if (optname == TCP_MD5SIG_EXT &&
1514 cmd.tcpm_flags & TCP_MD5SIG_FLAG_PREFIX) {
1515 prefixlen = cmd.tcpm_prefixlen;
1516 if (prefixlen > 32)
1517 return -EINVAL;
1518 }
1519
1520 if (optname == TCP_MD5SIG_EXT && cmd.tcpm_ifindex &&
1521 cmd.tcpm_flags & TCP_MD5SIG_FLAG_IFINDEX) {
1522 struct net_device *dev;
1523
1524 rcu_read_lock();
1525 dev = dev_get_by_index_rcu(sock_net(sk), cmd.tcpm_ifindex);
1526 if (dev && netif_is_l3_master(dev))
1527 l3index = dev->ifindex;
1528
1529 rcu_read_unlock();
1530
1531 /* ok to reference set/not set outside of rcu;
1532 * right now device MUST be an L3 master
1533 */
1534 if (!dev || !l3index)
1535 return -EINVAL;
1536 }
1537
1538 addr = (union tcp_md5_addr *)&sin->sin_addr.s_addr;
1539
1540 if (!cmd.tcpm_keylen)
1541 return tcp_md5_do_del(sk, addr, AF_INET, prefixlen, l3index, flags);
1542
1543 if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN)
1544 return -EINVAL;
1545
1546 /* Don't allow keys for peers that have a matching TCP-AO key.
1547 * See the comment in tcp_ao_add_cmd()
1548 */
1549 if (tcp_ao_required(sk, addr, AF_INET, l3flag ? l3index : -1, false))
1550 return -EKEYREJECTED;
1551
1552 return tcp_md5_do_add(sk, addr, AF_INET, prefixlen, l3index, flags,
1553 cmd.tcpm_key, cmd.tcpm_keylen);
1554}
1555
1556static int tcp_v4_md5_hash_headers(struct tcp_sigpool *hp,
1557 __be32 daddr, __be32 saddr,
1558 const struct tcphdr *th, int nbytes)
1559{
1560 struct tcp4_pseudohdr *bp;
1561 struct scatterlist sg;
1562 struct tcphdr *_th;
1563
1564 bp = hp->scratch;
1565 bp->saddr = saddr;
1566 bp->daddr = daddr;
1567 bp->pad = 0;
1568 bp->protocol = IPPROTO_TCP;
1569 bp->len = cpu_to_be16(nbytes);
1570
1571 _th = (struct tcphdr *)(bp + 1);
1572 memcpy(_th, th, sizeof(*th));
1573 _th->check = 0;
1574
1575 sg_init_one(&sg, bp, sizeof(*bp) + sizeof(*th));
1576 ahash_request_set_crypt(hp->req, &sg, NULL,
1577 sizeof(*bp) + sizeof(*th));
1578 return crypto_ahash_update(hp->req);
1579}
1580
1581static int tcp_v4_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key,
1582 __be32 daddr, __be32 saddr, const struct tcphdr *th)
1583{
1584 struct tcp_sigpool hp;
1585
1586 if (tcp_sigpool_start(tcp_md5_sigpool_id, &hp))
1587 goto clear_hash_nostart;
1588
1589 if (crypto_ahash_init(hp.req))
1590 goto clear_hash;
1591 if (tcp_v4_md5_hash_headers(&hp, daddr, saddr, th, th->doff << 2))
1592 goto clear_hash;
1593 if (tcp_md5_hash_key(&hp, key))
1594 goto clear_hash;
1595 ahash_request_set_crypt(hp.req, NULL, md5_hash, 0);
1596 if (crypto_ahash_final(hp.req))
1597 goto clear_hash;
1598
1599 tcp_sigpool_end(&hp);
1600 return 0;
1601
1602clear_hash:
1603 tcp_sigpool_end(&hp);
1604clear_hash_nostart:
1605 memset(md5_hash, 0, 16);
1606 return 1;
1607}
1608
1609int tcp_v4_md5_hash_skb(char *md5_hash, const struct tcp_md5sig_key *key,
1610 const struct sock *sk,
1611 const struct sk_buff *skb)
1612{
1613 const struct tcphdr *th = tcp_hdr(skb);
1614 struct tcp_sigpool hp;
1615 __be32 saddr, daddr;
1616
1617 if (sk) { /* valid for establish/request sockets */
1618 saddr = sk->sk_rcv_saddr;
1619 daddr = sk->sk_daddr;
1620 } else {
1621 const struct iphdr *iph = ip_hdr(skb);
1622 saddr = iph->saddr;
1623 daddr = iph->daddr;
1624 }
1625
1626 if (tcp_sigpool_start(tcp_md5_sigpool_id, &hp))
1627 goto clear_hash_nostart;
1628
1629 if (crypto_ahash_init(hp.req))
1630 goto clear_hash;
1631
1632 if (tcp_v4_md5_hash_headers(&hp, daddr, saddr, th, skb->len))
1633 goto clear_hash;
1634 if (tcp_sigpool_hash_skb_data(&hp, skb, th->doff << 2))
1635 goto clear_hash;
1636 if (tcp_md5_hash_key(&hp, key))
1637 goto clear_hash;
1638 ahash_request_set_crypt(hp.req, NULL, md5_hash, 0);
1639 if (crypto_ahash_final(hp.req))
1640 goto clear_hash;
1641
1642 tcp_sigpool_end(&hp);
1643 return 0;
1644
1645clear_hash:
1646 tcp_sigpool_end(&hp);
1647clear_hash_nostart:
1648 memset(md5_hash, 0, 16);
1649 return 1;
1650}
1651EXPORT_SYMBOL(tcp_v4_md5_hash_skb);
1652
1653#endif
1654
1655static void tcp_v4_init_req(struct request_sock *req,
1656 const struct sock *sk_listener,
1657 struct sk_buff *skb)
1658{
1659 struct inet_request_sock *ireq = inet_rsk(req);
1660 struct net *net = sock_net(sk_listener);
1661
1662 sk_rcv_saddr_set(req_to_sk(req), ip_hdr(skb)->daddr);
1663 sk_daddr_set(req_to_sk(req), ip_hdr(skb)->saddr);
1664 RCU_INIT_POINTER(ireq->ireq_opt, tcp_v4_save_options(net, skb));
1665}
1666
1667static struct dst_entry *tcp_v4_route_req(const struct sock *sk,
1668 struct sk_buff *skb,
1669 struct flowi *fl,
1670 struct request_sock *req)
1671{
1672 tcp_v4_init_req(req, sk, skb);
1673
1674 if (security_inet_conn_request(sk, skb, req))
1675 return NULL;
1676
1677 return inet_csk_route_req(sk, &fl->u.ip4, req);
1678}
1679
1680struct request_sock_ops tcp_request_sock_ops __read_mostly = {
1681 .family = PF_INET,
1682 .obj_size = sizeof(struct tcp_request_sock),
1683 .rtx_syn_ack = tcp_rtx_synack,
1684 .send_ack = tcp_v4_reqsk_send_ack,
1685 .destructor = tcp_v4_reqsk_destructor,
1686 .send_reset = tcp_v4_send_reset,
1687 .syn_ack_timeout = tcp_syn_ack_timeout,
1688};
1689
1690const struct tcp_request_sock_ops tcp_request_sock_ipv4_ops = {
1691 .mss_clamp = TCP_MSS_DEFAULT,
1692#ifdef CONFIG_TCP_MD5SIG
1693 .req_md5_lookup = tcp_v4_md5_lookup,
1694 .calc_md5_hash = tcp_v4_md5_hash_skb,
1695#endif
1696#ifdef CONFIG_TCP_AO
1697 .ao_lookup = tcp_v4_ao_lookup_rsk,
1698 .ao_calc_key = tcp_v4_ao_calc_key_rsk,
1699 .ao_synack_hash = tcp_v4_ao_synack_hash,
1700#endif
1701#ifdef CONFIG_SYN_COOKIES
1702 .cookie_init_seq = cookie_v4_init_sequence,
1703#endif
1704 .route_req = tcp_v4_route_req,
1705 .init_seq = tcp_v4_init_seq,
1706 .init_ts_off = tcp_v4_init_ts_off,
1707 .send_synack = tcp_v4_send_synack,
1708};
1709
1710int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
1711{
1712 /* Never answer to SYNs send to broadcast or multicast */
1713 if (skb_rtable(skb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
1714 goto drop;
1715
1716 return tcp_conn_request(&tcp_request_sock_ops,
1717 &tcp_request_sock_ipv4_ops, sk, skb);
1718
1719drop:
1720 tcp_listendrop(sk);
1721 return 0;
1722}
1723EXPORT_SYMBOL(tcp_v4_conn_request);
1724
1725
1726/*
1727 * The three way handshake has completed - we got a valid synack -
1728 * now create the new socket.
1729 */
1730struct sock *tcp_v4_syn_recv_sock(const struct sock *sk, struct sk_buff *skb,
1731 struct request_sock *req,
1732 struct dst_entry *dst,
1733 struct request_sock *req_unhash,
1734 bool *own_req)
1735{
1736 struct inet_request_sock *ireq;
1737 bool found_dup_sk = false;
1738 struct inet_sock *newinet;
1739 struct tcp_sock *newtp;
1740 struct sock *newsk;
1741#ifdef CONFIG_TCP_MD5SIG
1742 const union tcp_md5_addr *addr;
1743 struct tcp_md5sig_key *key;
1744 int l3index;
1745#endif
1746 struct ip_options_rcu *inet_opt;
1747
1748 if (sk_acceptq_is_full(sk))
1749 goto exit_overflow;
1750
1751 newsk = tcp_create_openreq_child(sk, req, skb);
1752 if (!newsk)
1753 goto exit_nonewsk;
1754
1755 newsk->sk_gso_type = SKB_GSO_TCPV4;
1756 inet_sk_rx_dst_set(newsk, skb);
1757
1758 newtp = tcp_sk(newsk);
1759 newinet = inet_sk(newsk);
1760 ireq = inet_rsk(req);
1761 sk_daddr_set(newsk, ireq->ir_rmt_addr);
1762 sk_rcv_saddr_set(newsk, ireq->ir_loc_addr);
1763 newsk->sk_bound_dev_if = ireq->ir_iif;
1764 newinet->inet_saddr = ireq->ir_loc_addr;
1765 inet_opt = rcu_dereference(ireq->ireq_opt);
1766 RCU_INIT_POINTER(newinet->inet_opt, inet_opt);
1767 newinet->mc_index = inet_iif(skb);
1768 newinet->mc_ttl = ip_hdr(skb)->ttl;
1769 newinet->rcv_tos = ip_hdr(skb)->tos;
1770 inet_csk(newsk)->icsk_ext_hdr_len = 0;
1771 if (inet_opt)
1772 inet_csk(newsk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
1773 atomic_set(&newinet->inet_id, get_random_u16());
1774
1775 /* Set ToS of the new socket based upon the value of incoming SYN.
1776 * ECT bits are set later in tcp_init_transfer().
1777 */
1778 if (READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_reflect_tos))
1779 newinet->tos = tcp_rsk(req)->syn_tos & ~INET_ECN_MASK;
1780
1781 if (!dst) {
1782 dst = inet_csk_route_child_sock(sk, newsk, req);
1783 if (!dst)
1784 goto put_and_exit;
1785 } else {
1786 /* syncookie case : see end of cookie_v4_check() */
1787 }
1788 sk_setup_caps(newsk, dst);
1789
1790 tcp_ca_openreq_child(newsk, dst);
1791
1792 tcp_sync_mss(newsk, dst_mtu(dst));
1793 newtp->advmss = tcp_mss_clamp(tcp_sk(sk), dst_metric_advmss(dst));
1794
1795 tcp_initialize_rcv_mss(newsk);
1796
1797#ifdef CONFIG_TCP_MD5SIG
1798 l3index = l3mdev_master_ifindex_by_index(sock_net(sk), ireq->ir_iif);
1799 /* Copy over the MD5 key from the original socket */
1800 addr = (union tcp_md5_addr *)&newinet->inet_daddr;
1801 key = tcp_md5_do_lookup(sk, l3index, addr, AF_INET);
1802 if (key && !tcp_rsk_used_ao(req)) {
1803 if (tcp_md5_key_copy(newsk, addr, AF_INET, 32, l3index, key))
1804 goto put_and_exit;
1805 sk_gso_disable(newsk);
1806 }
1807#endif
1808#ifdef CONFIG_TCP_AO
1809 if (tcp_ao_copy_all_matching(sk, newsk, req, skb, AF_INET))
1810 goto put_and_exit; /* OOM, release back memory */
1811#endif
1812
1813 if (__inet_inherit_port(sk, newsk) < 0)
1814 goto put_and_exit;
1815 *own_req = inet_ehash_nolisten(newsk, req_to_sk(req_unhash),
1816 &found_dup_sk);
1817 if (likely(*own_req)) {
1818 tcp_move_syn(newtp, req);
1819 ireq->ireq_opt = NULL;
1820 } else {
1821 newinet->inet_opt = NULL;
1822
1823 if (!req_unhash && found_dup_sk) {
1824 /* This code path should only be executed in the
1825 * syncookie case only
1826 */
1827 bh_unlock_sock(newsk);
1828 sock_put(newsk);
1829 newsk = NULL;
1830 }
1831 }
1832 return newsk;
1833
1834exit_overflow:
1835 NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
1836exit_nonewsk:
1837 dst_release(dst);
1838exit:
1839 tcp_listendrop(sk);
1840 return NULL;
1841put_and_exit:
1842 newinet->inet_opt = NULL;
1843 inet_csk_prepare_forced_close(newsk);
1844 tcp_done(newsk);
1845 goto exit;
1846}
1847EXPORT_SYMBOL(tcp_v4_syn_recv_sock);
1848
1849static struct sock *tcp_v4_cookie_check(struct sock *sk, struct sk_buff *skb)
1850{
1851#ifdef CONFIG_SYN_COOKIES
1852 const struct tcphdr *th = tcp_hdr(skb);
1853
1854 if (!th->syn)
1855 sk = cookie_v4_check(sk, skb);
1856#endif
1857 return sk;
1858}
1859
1860u16 tcp_v4_get_syncookie(struct sock *sk, struct iphdr *iph,
1861 struct tcphdr *th, u32 *cookie)
1862{
1863 u16 mss = 0;
1864#ifdef CONFIG_SYN_COOKIES
1865 mss = tcp_get_syncookie_mss(&tcp_request_sock_ops,
1866 &tcp_request_sock_ipv4_ops, sk, th);
1867 if (mss) {
1868 *cookie = __cookie_v4_init_sequence(iph, th, &mss);
1869 tcp_synq_overflow(sk);
1870 }
1871#endif
1872 return mss;
1873}
1874
1875INDIRECT_CALLABLE_DECLARE(struct dst_entry *ipv4_dst_check(struct dst_entry *,
1876 u32));
1877/* The socket must have it's spinlock held when we get
1878 * here, unless it is a TCP_LISTEN socket.
1879 *
1880 * We have a potential double-lock case here, so even when
1881 * doing backlog processing we use the BH locking scheme.
1882 * This is because we cannot sleep with the original spinlock
1883 * held.
1884 */
1885int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
1886{
1887 enum skb_drop_reason reason;
1888 struct sock *rsk;
1889
1890 if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
1891 struct dst_entry *dst;
1892
1893 dst = rcu_dereference_protected(sk->sk_rx_dst,
1894 lockdep_sock_is_held(sk));
1895
1896 sock_rps_save_rxhash(sk, skb);
1897 sk_mark_napi_id(sk, skb);
1898 if (dst) {
1899 if (sk->sk_rx_dst_ifindex != skb->skb_iif ||
1900 !INDIRECT_CALL_1(dst->ops->check, ipv4_dst_check,
1901 dst, 0)) {
1902 RCU_INIT_POINTER(sk->sk_rx_dst, NULL);
1903 dst_release(dst);
1904 }
1905 }
1906 tcp_rcv_established(sk, skb);
1907 return 0;
1908 }
1909
1910 reason = SKB_DROP_REASON_NOT_SPECIFIED;
1911 if (tcp_checksum_complete(skb))
1912 goto csum_err;
1913
1914 if (sk->sk_state == TCP_LISTEN) {
1915 struct sock *nsk = tcp_v4_cookie_check(sk, skb);
1916
1917 if (!nsk)
1918 goto discard;
1919 if (nsk != sk) {
1920 if (tcp_child_process(sk, nsk, skb)) {
1921 rsk = nsk;
1922 goto reset;
1923 }
1924 return 0;
1925 }
1926 } else
1927 sock_rps_save_rxhash(sk, skb);
1928
1929 if (tcp_rcv_state_process(sk, skb)) {
1930 rsk = sk;
1931 goto reset;
1932 }
1933 return 0;
1934
1935reset:
1936 tcp_v4_send_reset(rsk, skb);
1937discard:
1938 kfree_skb_reason(skb, reason);
1939 /* Be careful here. If this function gets more complicated and
1940 * gcc suffers from register pressure on the x86, sk (in %ebx)
1941 * might be destroyed here. This current version compiles correctly,
1942 * but you have been warned.
1943 */
1944 return 0;
1945
1946csum_err:
1947 reason = SKB_DROP_REASON_TCP_CSUM;
1948 trace_tcp_bad_csum(skb);
1949 TCP_INC_STATS(sock_net(sk), TCP_MIB_CSUMERRORS);
1950 TCP_INC_STATS(sock_net(sk), TCP_MIB_INERRS);
1951 goto discard;
1952}
1953EXPORT_SYMBOL(tcp_v4_do_rcv);
1954
1955int tcp_v4_early_demux(struct sk_buff *skb)
1956{
1957 struct net *net = dev_net(skb->dev);
1958 const struct iphdr *iph;
1959 const struct tcphdr *th;
1960 struct sock *sk;
1961
1962 if (skb->pkt_type != PACKET_HOST)
1963 return 0;
1964
1965 if (!pskb_may_pull(skb, skb_transport_offset(skb) + sizeof(struct tcphdr)))
1966 return 0;
1967
1968 iph = ip_hdr(skb);
1969 th = tcp_hdr(skb);
1970
1971 if (th->doff < sizeof(struct tcphdr) / 4)
1972 return 0;
1973
1974 sk = __inet_lookup_established(net, net->ipv4.tcp_death_row.hashinfo,
1975 iph->saddr, th->source,
1976 iph->daddr, ntohs(th->dest),
1977 skb->skb_iif, inet_sdif(skb));
1978 if (sk) {
1979 skb->sk = sk;
1980 skb->destructor = sock_edemux;
1981 if (sk_fullsock(sk)) {
1982 struct dst_entry *dst = rcu_dereference(sk->sk_rx_dst);
1983
1984 if (dst)
1985 dst = dst_check(dst, 0);
1986 if (dst &&
1987 sk->sk_rx_dst_ifindex == skb->skb_iif)
1988 skb_dst_set_noref(skb, dst);
1989 }
1990 }
1991 return 0;
1992}
1993
1994bool tcp_add_backlog(struct sock *sk, struct sk_buff *skb,
1995 enum skb_drop_reason *reason)
1996{
1997 u32 limit, tail_gso_size, tail_gso_segs;
1998 struct skb_shared_info *shinfo;
1999 const struct tcphdr *th;
2000 struct tcphdr *thtail;
2001 struct sk_buff *tail;
2002 unsigned int hdrlen;
2003 bool fragstolen;
2004 u32 gso_segs;
2005 u32 gso_size;
2006 int delta;
2007
2008 /* In case all data was pulled from skb frags (in __pskb_pull_tail()),
2009 * we can fix skb->truesize to its real value to avoid future drops.
2010 * This is valid because skb is not yet charged to the socket.
2011 * It has been noticed pure SACK packets were sometimes dropped
2012 * (if cooked by drivers without copybreak feature).
2013 */
2014 skb_condense(skb);
2015
2016 skb_dst_drop(skb);
2017
2018 if (unlikely(tcp_checksum_complete(skb))) {
2019 bh_unlock_sock(sk);
2020 trace_tcp_bad_csum(skb);
2021 *reason = SKB_DROP_REASON_TCP_CSUM;
2022 __TCP_INC_STATS(sock_net(sk), TCP_MIB_CSUMERRORS);
2023 __TCP_INC_STATS(sock_net(sk), TCP_MIB_INERRS);
2024 return true;
2025 }
2026
2027 /* Attempt coalescing to last skb in backlog, even if we are
2028 * above the limits.
2029 * This is okay because skb capacity is limited to MAX_SKB_FRAGS.
2030 */
2031 th = (const struct tcphdr *)skb->data;
2032 hdrlen = th->doff * 4;
2033
2034 tail = sk->sk_backlog.tail;
2035 if (!tail)
2036 goto no_coalesce;
2037 thtail = (struct tcphdr *)tail->data;
2038
2039 if (TCP_SKB_CB(tail)->end_seq != TCP_SKB_CB(skb)->seq ||
2040 TCP_SKB_CB(tail)->ip_dsfield != TCP_SKB_CB(skb)->ip_dsfield ||
2041 ((TCP_SKB_CB(tail)->tcp_flags |
2042 TCP_SKB_CB(skb)->tcp_flags) & (TCPHDR_SYN | TCPHDR_RST | TCPHDR_URG)) ||
2043 !((TCP_SKB_CB(tail)->tcp_flags &
2044 TCP_SKB_CB(skb)->tcp_flags) & TCPHDR_ACK) ||
2045 ((TCP_SKB_CB(tail)->tcp_flags ^
2046 TCP_SKB_CB(skb)->tcp_flags) & (TCPHDR_ECE | TCPHDR_CWR)) ||
2047#ifdef CONFIG_TLS_DEVICE
2048 tail->decrypted != skb->decrypted ||
2049#endif
2050 !mptcp_skb_can_collapse(tail, skb) ||
2051 thtail->doff != th->doff ||
2052 memcmp(thtail + 1, th + 1, hdrlen - sizeof(*th)))
2053 goto no_coalesce;
2054
2055 __skb_pull(skb, hdrlen);
2056
2057 shinfo = skb_shinfo(skb);
2058 gso_size = shinfo->gso_size ?: skb->len;
2059 gso_segs = shinfo->gso_segs ?: 1;
2060
2061 shinfo = skb_shinfo(tail);
2062 tail_gso_size = shinfo->gso_size ?: (tail->len - hdrlen);
2063 tail_gso_segs = shinfo->gso_segs ?: 1;
2064
2065 if (skb_try_coalesce(tail, skb, &fragstolen, &delta)) {
2066 TCP_SKB_CB(tail)->end_seq = TCP_SKB_CB(skb)->end_seq;
2067
2068 if (likely(!before(TCP_SKB_CB(skb)->ack_seq, TCP_SKB_CB(tail)->ack_seq))) {
2069 TCP_SKB_CB(tail)->ack_seq = TCP_SKB_CB(skb)->ack_seq;
2070 thtail->window = th->window;
2071 }
2072
2073 /* We have to update both TCP_SKB_CB(tail)->tcp_flags and
2074 * thtail->fin, so that the fast path in tcp_rcv_established()
2075 * is not entered if we append a packet with a FIN.
2076 * SYN, RST, URG are not present.
2077 * ACK is set on both packets.
2078 * PSH : we do not really care in TCP stack,
2079 * at least for 'GRO' packets.
2080 */
2081 thtail->fin |= th->fin;
2082 TCP_SKB_CB(tail)->tcp_flags |= TCP_SKB_CB(skb)->tcp_flags;
2083
2084 if (TCP_SKB_CB(skb)->has_rxtstamp) {
2085 TCP_SKB_CB(tail)->has_rxtstamp = true;
2086 tail->tstamp = skb->tstamp;
2087 skb_hwtstamps(tail)->hwtstamp = skb_hwtstamps(skb)->hwtstamp;
2088 }
2089
2090 /* Not as strict as GRO. We only need to carry mss max value */
2091 shinfo->gso_size = max(gso_size, tail_gso_size);
2092 shinfo->gso_segs = min_t(u32, gso_segs + tail_gso_segs, 0xFFFF);
2093
2094 sk->sk_backlog.len += delta;
2095 __NET_INC_STATS(sock_net(sk),
2096 LINUX_MIB_TCPBACKLOGCOALESCE);
2097 kfree_skb_partial(skb, fragstolen);
2098 return false;
2099 }
2100 __skb_push(skb, hdrlen);
2101
2102no_coalesce:
2103 limit = (u32)READ_ONCE(sk->sk_rcvbuf) + (u32)(READ_ONCE(sk->sk_sndbuf) >> 1);
2104
2105 /* Only socket owner can try to collapse/prune rx queues
2106 * to reduce memory overhead, so add a little headroom here.
2107 * Few sockets backlog are possibly concurrently non empty.
2108 */
2109 limit += 64 * 1024;
2110
2111 if (unlikely(sk_add_backlog(sk, skb, limit))) {
2112 bh_unlock_sock(sk);
2113 *reason = SKB_DROP_REASON_SOCKET_BACKLOG;
2114 __NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPBACKLOGDROP);
2115 return true;
2116 }
2117 return false;
2118}
2119EXPORT_SYMBOL(tcp_add_backlog);
2120
2121int tcp_filter(struct sock *sk, struct sk_buff *skb)
2122{
2123 struct tcphdr *th = (struct tcphdr *)skb->data;
2124
2125 return sk_filter_trim_cap(sk, skb, th->doff * 4);
2126}
2127EXPORT_SYMBOL(tcp_filter);
2128
2129static void tcp_v4_restore_cb(struct sk_buff *skb)
2130{
2131 memmove(IPCB(skb), &TCP_SKB_CB(skb)->header.h4,
2132 sizeof(struct inet_skb_parm));
2133}
2134
2135static void tcp_v4_fill_cb(struct sk_buff *skb, const struct iphdr *iph,
2136 const struct tcphdr *th)
2137{
2138 /* This is tricky : We move IPCB at its correct location into TCP_SKB_CB()
2139 * barrier() makes sure compiler wont play fool^Waliasing games.
2140 */
2141 memmove(&TCP_SKB_CB(skb)->header.h4, IPCB(skb),
2142 sizeof(struct inet_skb_parm));
2143 barrier();
2144
2145 TCP_SKB_CB(skb)->seq = ntohl(th->seq);
2146 TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
2147 skb->len - th->doff * 4);
2148 TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
2149 TCP_SKB_CB(skb)->tcp_flags = tcp_flag_byte(th);
2150 TCP_SKB_CB(skb)->tcp_tw_isn = 0;
2151 TCP_SKB_CB(skb)->ip_dsfield = ipv4_get_dsfield(iph);
2152 TCP_SKB_CB(skb)->sacked = 0;
2153 TCP_SKB_CB(skb)->has_rxtstamp =
2154 skb->tstamp || skb_hwtstamps(skb)->hwtstamp;
2155}
2156
2157/*
2158 * From tcp_input.c
2159 */
2160
2161int tcp_v4_rcv(struct sk_buff *skb)
2162{
2163 struct net *net = dev_net(skb->dev);
2164 enum skb_drop_reason drop_reason;
2165 int sdif = inet_sdif(skb);
2166 int dif = inet_iif(skb);
2167 const struct iphdr *iph;
2168 const struct tcphdr *th;
2169 bool refcounted;
2170 struct sock *sk;
2171 int ret;
2172
2173 drop_reason = SKB_DROP_REASON_NOT_SPECIFIED;
2174 if (skb->pkt_type != PACKET_HOST)
2175 goto discard_it;
2176
2177 /* Count it even if it's bad */
2178 __TCP_INC_STATS(net, TCP_MIB_INSEGS);
2179
2180 if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
2181 goto discard_it;
2182
2183 th = (const struct tcphdr *)skb->data;
2184
2185 if (unlikely(th->doff < sizeof(struct tcphdr) / 4)) {
2186 drop_reason = SKB_DROP_REASON_PKT_TOO_SMALL;
2187 goto bad_packet;
2188 }
2189 if (!pskb_may_pull(skb, th->doff * 4))
2190 goto discard_it;
2191
2192 /* An explanation is required here, I think.
2193 * Packet length and doff are validated by header prediction,
2194 * provided case of th->doff==0 is eliminated.
2195 * So, we defer the checks. */
2196
2197 if (skb_checksum_init(skb, IPPROTO_TCP, inet_compute_pseudo))
2198 goto csum_error;
2199
2200 th = (const struct tcphdr *)skb->data;
2201 iph = ip_hdr(skb);
2202lookup:
2203 sk = __inet_lookup_skb(net->ipv4.tcp_death_row.hashinfo,
2204 skb, __tcp_hdrlen(th), th->source,
2205 th->dest, sdif, &refcounted);
2206 if (!sk)
2207 goto no_tcp_socket;
2208
2209process:
2210 if (sk->sk_state == TCP_TIME_WAIT)
2211 goto do_time_wait;
2212
2213 if (sk->sk_state == TCP_NEW_SYN_RECV) {
2214 struct request_sock *req = inet_reqsk(sk);
2215 bool req_stolen = false;
2216 struct sock *nsk;
2217
2218 sk = req->rsk_listener;
2219 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
2220 drop_reason = SKB_DROP_REASON_XFRM_POLICY;
2221 else
2222 drop_reason = tcp_inbound_hash(sk, req, skb,
2223 &iph->saddr, &iph->daddr,
2224 AF_INET, dif, sdif);
2225 if (unlikely(drop_reason)) {
2226 sk_drops_add(sk, skb);
2227 reqsk_put(req);
2228 goto discard_it;
2229 }
2230 if (tcp_checksum_complete(skb)) {
2231 reqsk_put(req);
2232 goto csum_error;
2233 }
2234 if (unlikely(sk->sk_state != TCP_LISTEN)) {
2235 nsk = reuseport_migrate_sock(sk, req_to_sk(req), skb);
2236 if (!nsk) {
2237 inet_csk_reqsk_queue_drop_and_put(sk, req);
2238 goto lookup;
2239 }
2240 sk = nsk;
2241 /* reuseport_migrate_sock() has already held one sk_refcnt
2242 * before returning.
2243 */
2244 } else {
2245 /* We own a reference on the listener, increase it again
2246 * as we might lose it too soon.
2247 */
2248 sock_hold(sk);
2249 }
2250 refcounted = true;
2251 nsk = NULL;
2252 if (!tcp_filter(sk, skb)) {
2253 th = (const struct tcphdr *)skb->data;
2254 iph = ip_hdr(skb);
2255 tcp_v4_fill_cb(skb, iph, th);
2256 nsk = tcp_check_req(sk, skb, req, false, &req_stolen);
2257 } else {
2258 drop_reason = SKB_DROP_REASON_SOCKET_FILTER;
2259 }
2260 if (!nsk) {
2261 reqsk_put(req);
2262 if (req_stolen) {
2263 /* Another cpu got exclusive access to req
2264 * and created a full blown socket.
2265 * Try to feed this packet to this socket
2266 * instead of discarding it.
2267 */
2268 tcp_v4_restore_cb(skb);
2269 sock_put(sk);
2270 goto lookup;
2271 }
2272 goto discard_and_relse;
2273 }
2274 nf_reset_ct(skb);
2275 if (nsk == sk) {
2276 reqsk_put(req);
2277 tcp_v4_restore_cb(skb);
2278 } else if (tcp_child_process(sk, nsk, skb)) {
2279 tcp_v4_send_reset(nsk, skb);
2280 goto discard_and_relse;
2281 } else {
2282 sock_put(sk);
2283 return 0;
2284 }
2285 }
2286
2287 if (static_branch_unlikely(&ip4_min_ttl)) {
2288 /* min_ttl can be changed concurrently from do_ip_setsockopt() */
2289 if (unlikely(iph->ttl < READ_ONCE(inet_sk(sk)->min_ttl))) {
2290 __NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP);
2291 drop_reason = SKB_DROP_REASON_TCP_MINTTL;
2292 goto discard_and_relse;
2293 }
2294 }
2295
2296 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb)) {
2297 drop_reason = SKB_DROP_REASON_XFRM_POLICY;
2298 goto discard_and_relse;
2299 }
2300
2301 drop_reason = tcp_inbound_hash(sk, NULL, skb, &iph->saddr, &iph->daddr,
2302 AF_INET, dif, sdif);
2303 if (drop_reason)
2304 goto discard_and_relse;
2305
2306 nf_reset_ct(skb);
2307
2308 if (tcp_filter(sk, skb)) {
2309 drop_reason = SKB_DROP_REASON_SOCKET_FILTER;
2310 goto discard_and_relse;
2311 }
2312 th = (const struct tcphdr *)skb->data;
2313 iph = ip_hdr(skb);
2314 tcp_v4_fill_cb(skb, iph, th);
2315
2316 skb->dev = NULL;
2317
2318 if (sk->sk_state == TCP_LISTEN) {
2319 ret = tcp_v4_do_rcv(sk, skb);
2320 goto put_and_return;
2321 }
2322
2323 sk_incoming_cpu_update(sk);
2324
2325 bh_lock_sock_nested(sk);
2326 tcp_segs_in(tcp_sk(sk), skb);
2327 ret = 0;
2328 if (!sock_owned_by_user(sk)) {
2329 ret = tcp_v4_do_rcv(sk, skb);
2330 } else {
2331 if (tcp_add_backlog(sk, skb, &drop_reason))
2332 goto discard_and_relse;
2333 }
2334 bh_unlock_sock(sk);
2335
2336put_and_return:
2337 if (refcounted)
2338 sock_put(sk);
2339
2340 return ret;
2341
2342no_tcp_socket:
2343 drop_reason = SKB_DROP_REASON_NO_SOCKET;
2344 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
2345 goto discard_it;
2346
2347 tcp_v4_fill_cb(skb, iph, th);
2348
2349 if (tcp_checksum_complete(skb)) {
2350csum_error:
2351 drop_reason = SKB_DROP_REASON_TCP_CSUM;
2352 trace_tcp_bad_csum(skb);
2353 __TCP_INC_STATS(net, TCP_MIB_CSUMERRORS);
2354bad_packet:
2355 __TCP_INC_STATS(net, TCP_MIB_INERRS);
2356 } else {
2357 tcp_v4_send_reset(NULL, skb);
2358 }
2359
2360discard_it:
2361 SKB_DR_OR(drop_reason, NOT_SPECIFIED);
2362 /* Discard frame. */
2363 kfree_skb_reason(skb, drop_reason);
2364 return 0;
2365
2366discard_and_relse:
2367 sk_drops_add(sk, skb);
2368 if (refcounted)
2369 sock_put(sk);
2370 goto discard_it;
2371
2372do_time_wait:
2373 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
2374 drop_reason = SKB_DROP_REASON_XFRM_POLICY;
2375 inet_twsk_put(inet_twsk(sk));
2376 goto discard_it;
2377 }
2378
2379 tcp_v4_fill_cb(skb, iph, th);
2380
2381 if (tcp_checksum_complete(skb)) {
2382 inet_twsk_put(inet_twsk(sk));
2383 goto csum_error;
2384 }
2385 switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) {
2386 case TCP_TW_SYN: {
2387 struct sock *sk2 = inet_lookup_listener(net,
2388 net->ipv4.tcp_death_row.hashinfo,
2389 skb, __tcp_hdrlen(th),
2390 iph->saddr, th->source,
2391 iph->daddr, th->dest,
2392 inet_iif(skb),
2393 sdif);
2394 if (sk2) {
2395 inet_twsk_deschedule_put(inet_twsk(sk));
2396 sk = sk2;
2397 tcp_v4_restore_cb(skb);
2398 refcounted = false;
2399 goto process;
2400 }
2401 }
2402 /* to ACK */
2403 fallthrough;
2404 case TCP_TW_ACK:
2405 tcp_v4_timewait_ack(sk, skb);
2406 break;
2407 case TCP_TW_RST:
2408 tcp_v4_send_reset(sk, skb);
2409 inet_twsk_deschedule_put(inet_twsk(sk));
2410 goto discard_it;
2411 case TCP_TW_SUCCESS:;
2412 }
2413 goto discard_it;
2414}
2415
2416static struct timewait_sock_ops tcp_timewait_sock_ops = {
2417 .twsk_obj_size = sizeof(struct tcp_timewait_sock),
2418 .twsk_unique = tcp_twsk_unique,
2419 .twsk_destructor= tcp_twsk_destructor,
2420};
2421
2422void inet_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb)
2423{
2424 struct dst_entry *dst = skb_dst(skb);
2425
2426 if (dst && dst_hold_safe(dst)) {
2427 rcu_assign_pointer(sk->sk_rx_dst, dst);
2428 sk->sk_rx_dst_ifindex = skb->skb_iif;
2429 }
2430}
2431EXPORT_SYMBOL(inet_sk_rx_dst_set);
2432
2433const struct inet_connection_sock_af_ops ipv4_specific = {
2434 .queue_xmit = ip_queue_xmit,
2435 .send_check = tcp_v4_send_check,
2436 .rebuild_header = inet_sk_rebuild_header,
2437 .sk_rx_dst_set = inet_sk_rx_dst_set,
2438 .conn_request = tcp_v4_conn_request,
2439 .syn_recv_sock = tcp_v4_syn_recv_sock,
2440 .net_header_len = sizeof(struct iphdr),
2441 .setsockopt = ip_setsockopt,
2442 .getsockopt = ip_getsockopt,
2443 .addr2sockaddr = inet_csk_addr2sockaddr,
2444 .sockaddr_len = sizeof(struct sockaddr_in),
2445 .mtu_reduced = tcp_v4_mtu_reduced,
2446};
2447EXPORT_SYMBOL(ipv4_specific);
2448
2449#if defined(CONFIG_TCP_MD5SIG) || defined(CONFIG_TCP_AO)
2450static const struct tcp_sock_af_ops tcp_sock_ipv4_specific = {
2451#ifdef CONFIG_TCP_MD5SIG
2452 .md5_lookup = tcp_v4_md5_lookup,
2453 .calc_md5_hash = tcp_v4_md5_hash_skb,
2454 .md5_parse = tcp_v4_parse_md5_keys,
2455#endif
2456#ifdef CONFIG_TCP_AO
2457 .ao_lookup = tcp_v4_ao_lookup,
2458 .calc_ao_hash = tcp_v4_ao_hash_skb,
2459 .ao_parse = tcp_v4_parse_ao,
2460 .ao_calc_key_sk = tcp_v4_ao_calc_key_sk,
2461#endif
2462};
2463#endif
2464
2465/* NOTE: A lot of things set to zero explicitly by call to
2466 * sk_alloc() so need not be done here.
2467 */
2468static int tcp_v4_init_sock(struct sock *sk)
2469{
2470 struct inet_connection_sock *icsk = inet_csk(sk);
2471
2472 tcp_init_sock(sk);
2473
2474 icsk->icsk_af_ops = &ipv4_specific;
2475
2476#if defined(CONFIG_TCP_MD5SIG) || defined(CONFIG_TCP_AO)
2477 tcp_sk(sk)->af_specific = &tcp_sock_ipv4_specific;
2478#endif
2479
2480 return 0;
2481}
2482
2483#ifdef CONFIG_TCP_MD5SIG
2484static void tcp_md5sig_info_free_rcu(struct rcu_head *head)
2485{
2486 struct tcp_md5sig_info *md5sig;
2487
2488 md5sig = container_of(head, struct tcp_md5sig_info, rcu);
2489 kfree(md5sig);
2490 static_branch_slow_dec_deferred(&tcp_md5_needed);
2491 tcp_md5_release_sigpool();
2492}
2493#endif
2494
2495void tcp_v4_destroy_sock(struct sock *sk)
2496{
2497 struct tcp_sock *tp = tcp_sk(sk);
2498
2499 trace_tcp_destroy_sock(sk);
2500
2501 tcp_clear_xmit_timers(sk);
2502
2503 tcp_cleanup_congestion_control(sk);
2504
2505 tcp_cleanup_ulp(sk);
2506
2507 /* Cleanup up the write buffer. */
2508 tcp_write_queue_purge(sk);
2509
2510 /* Check if we want to disable active TFO */
2511 tcp_fastopen_active_disable_ofo_check(sk);
2512
2513 /* Cleans up our, hopefully empty, out_of_order_queue. */
2514 skb_rbtree_purge(&tp->out_of_order_queue);
2515
2516#ifdef CONFIG_TCP_MD5SIG
2517 /* Clean up the MD5 key list, if any */
2518 if (tp->md5sig_info) {
2519 struct tcp_md5sig_info *md5sig;
2520
2521 md5sig = rcu_dereference_protected(tp->md5sig_info, 1);
2522 tcp_clear_md5_list(sk);
2523 call_rcu(&md5sig->rcu, tcp_md5sig_info_free_rcu);
2524 rcu_assign_pointer(tp->md5sig_info, NULL);
2525 }
2526#endif
2527 tcp_ao_destroy_sock(sk, false);
2528
2529 /* Clean up a referenced TCP bind bucket. */
2530 if (inet_csk(sk)->icsk_bind_hash)
2531 inet_put_port(sk);
2532
2533 BUG_ON(rcu_access_pointer(tp->fastopen_rsk));
2534
2535 /* If socket is aborted during connect operation */
2536 tcp_free_fastopen_req(tp);
2537 tcp_fastopen_destroy_cipher(sk);
2538 tcp_saved_syn_free(tp);
2539
2540 sk_sockets_allocated_dec(sk);
2541}
2542EXPORT_SYMBOL(tcp_v4_destroy_sock);
2543
2544#ifdef CONFIG_PROC_FS
2545/* Proc filesystem TCP sock list dumping. */
2546
2547static unsigned short seq_file_family(const struct seq_file *seq);
2548
2549static bool seq_sk_match(struct seq_file *seq, const struct sock *sk)
2550{
2551 unsigned short family = seq_file_family(seq);
2552
2553 /* AF_UNSPEC is used as a match all */
2554 return ((family == AF_UNSPEC || family == sk->sk_family) &&
2555 net_eq(sock_net(sk), seq_file_net(seq)));
2556}
2557
2558/* Find a non empty bucket (starting from st->bucket)
2559 * and return the first sk from it.
2560 */
2561static void *listening_get_first(struct seq_file *seq)
2562{
2563 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo;
2564 struct tcp_iter_state *st = seq->private;
2565
2566 st->offset = 0;
2567 for (; st->bucket <= hinfo->lhash2_mask; st->bucket++) {
2568 struct inet_listen_hashbucket *ilb2;
2569 struct hlist_nulls_node *node;
2570 struct sock *sk;
2571
2572 ilb2 = &hinfo->lhash2[st->bucket];
2573 if (hlist_nulls_empty(&ilb2->nulls_head))
2574 continue;
2575
2576 spin_lock(&ilb2->lock);
2577 sk_nulls_for_each(sk, node, &ilb2->nulls_head) {
2578 if (seq_sk_match(seq, sk))
2579 return sk;
2580 }
2581 spin_unlock(&ilb2->lock);
2582 }
2583
2584 return NULL;
2585}
2586
2587/* Find the next sk of "cur" within the same bucket (i.e. st->bucket).
2588 * If "cur" is the last one in the st->bucket,
2589 * call listening_get_first() to return the first sk of the next
2590 * non empty bucket.
2591 */
2592static void *listening_get_next(struct seq_file *seq, void *cur)
2593{
2594 struct tcp_iter_state *st = seq->private;
2595 struct inet_listen_hashbucket *ilb2;
2596 struct hlist_nulls_node *node;
2597 struct inet_hashinfo *hinfo;
2598 struct sock *sk = cur;
2599
2600 ++st->num;
2601 ++st->offset;
2602
2603 sk = sk_nulls_next(sk);
2604 sk_nulls_for_each_from(sk, node) {
2605 if (seq_sk_match(seq, sk))
2606 return sk;
2607 }
2608
2609 hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo;
2610 ilb2 = &hinfo->lhash2[st->bucket];
2611 spin_unlock(&ilb2->lock);
2612 ++st->bucket;
2613 return listening_get_first(seq);
2614}
2615
2616static void *listening_get_idx(struct seq_file *seq, loff_t *pos)
2617{
2618 struct tcp_iter_state *st = seq->private;
2619 void *rc;
2620
2621 st->bucket = 0;
2622 st->offset = 0;
2623 rc = listening_get_first(seq);
2624
2625 while (rc && *pos) {
2626 rc = listening_get_next(seq, rc);
2627 --*pos;
2628 }
2629 return rc;
2630}
2631
2632static inline bool empty_bucket(struct inet_hashinfo *hinfo,
2633 const struct tcp_iter_state *st)
2634{
2635 return hlist_nulls_empty(&hinfo->ehash[st->bucket].chain);
2636}
2637
2638/*
2639 * Get first established socket starting from bucket given in st->bucket.
2640 * If st->bucket is zero, the very first socket in the hash is returned.
2641 */
2642static void *established_get_first(struct seq_file *seq)
2643{
2644 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo;
2645 struct tcp_iter_state *st = seq->private;
2646
2647 st->offset = 0;
2648 for (; st->bucket <= hinfo->ehash_mask; ++st->bucket) {
2649 struct sock *sk;
2650 struct hlist_nulls_node *node;
2651 spinlock_t *lock = inet_ehash_lockp(hinfo, st->bucket);
2652
2653 cond_resched();
2654
2655 /* Lockless fast path for the common case of empty buckets */
2656 if (empty_bucket(hinfo, st))
2657 continue;
2658
2659 spin_lock_bh(lock);
2660 sk_nulls_for_each(sk, node, &hinfo->ehash[st->bucket].chain) {
2661 if (seq_sk_match(seq, sk))
2662 return sk;
2663 }
2664 spin_unlock_bh(lock);
2665 }
2666
2667 return NULL;
2668}
2669
2670static void *established_get_next(struct seq_file *seq, void *cur)
2671{
2672 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo;
2673 struct tcp_iter_state *st = seq->private;
2674 struct hlist_nulls_node *node;
2675 struct sock *sk = cur;
2676
2677 ++st->num;
2678 ++st->offset;
2679
2680 sk = sk_nulls_next(sk);
2681
2682 sk_nulls_for_each_from(sk, node) {
2683 if (seq_sk_match(seq, sk))
2684 return sk;
2685 }
2686
2687 spin_unlock_bh(inet_ehash_lockp(hinfo, st->bucket));
2688 ++st->bucket;
2689 return established_get_first(seq);
2690}
2691
2692static void *established_get_idx(struct seq_file *seq, loff_t pos)
2693{
2694 struct tcp_iter_state *st = seq->private;
2695 void *rc;
2696
2697 st->bucket = 0;
2698 rc = established_get_first(seq);
2699
2700 while (rc && pos) {
2701 rc = established_get_next(seq, rc);
2702 --pos;
2703 }
2704 return rc;
2705}
2706
2707static void *tcp_get_idx(struct seq_file *seq, loff_t pos)
2708{
2709 void *rc;
2710 struct tcp_iter_state *st = seq->private;
2711
2712 st->state = TCP_SEQ_STATE_LISTENING;
2713 rc = listening_get_idx(seq, &pos);
2714
2715 if (!rc) {
2716 st->state = TCP_SEQ_STATE_ESTABLISHED;
2717 rc = established_get_idx(seq, pos);
2718 }
2719
2720 return rc;
2721}
2722
2723static void *tcp_seek_last_pos(struct seq_file *seq)
2724{
2725 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo;
2726 struct tcp_iter_state *st = seq->private;
2727 int bucket = st->bucket;
2728 int offset = st->offset;
2729 int orig_num = st->num;
2730 void *rc = NULL;
2731
2732 switch (st->state) {
2733 case TCP_SEQ_STATE_LISTENING:
2734 if (st->bucket > hinfo->lhash2_mask)
2735 break;
2736 rc = listening_get_first(seq);
2737 while (offset-- && rc && bucket == st->bucket)
2738 rc = listening_get_next(seq, rc);
2739 if (rc)
2740 break;
2741 st->bucket = 0;
2742 st->state = TCP_SEQ_STATE_ESTABLISHED;
2743 fallthrough;
2744 case TCP_SEQ_STATE_ESTABLISHED:
2745 if (st->bucket > hinfo->ehash_mask)
2746 break;
2747 rc = established_get_first(seq);
2748 while (offset-- && rc && bucket == st->bucket)
2749 rc = established_get_next(seq, rc);
2750 }
2751
2752 st->num = orig_num;
2753
2754 return rc;
2755}
2756
2757void *tcp_seq_start(struct seq_file *seq, loff_t *pos)
2758{
2759 struct tcp_iter_state *st = seq->private;
2760 void *rc;
2761
2762 if (*pos && *pos == st->last_pos) {
2763 rc = tcp_seek_last_pos(seq);
2764 if (rc)
2765 goto out;
2766 }
2767
2768 st->state = TCP_SEQ_STATE_LISTENING;
2769 st->num = 0;
2770 st->bucket = 0;
2771 st->offset = 0;
2772 rc = *pos ? tcp_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
2773
2774out:
2775 st->last_pos = *pos;
2776 return rc;
2777}
2778EXPORT_SYMBOL(tcp_seq_start);
2779
2780void *tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2781{
2782 struct tcp_iter_state *st = seq->private;
2783 void *rc = NULL;
2784
2785 if (v == SEQ_START_TOKEN) {
2786 rc = tcp_get_idx(seq, 0);
2787 goto out;
2788 }
2789
2790 switch (st->state) {
2791 case TCP_SEQ_STATE_LISTENING:
2792 rc = listening_get_next(seq, v);
2793 if (!rc) {
2794 st->state = TCP_SEQ_STATE_ESTABLISHED;
2795 st->bucket = 0;
2796 st->offset = 0;
2797 rc = established_get_first(seq);
2798 }
2799 break;
2800 case TCP_SEQ_STATE_ESTABLISHED:
2801 rc = established_get_next(seq, v);
2802 break;
2803 }
2804out:
2805 ++*pos;
2806 st->last_pos = *pos;
2807 return rc;
2808}
2809EXPORT_SYMBOL(tcp_seq_next);
2810
2811void tcp_seq_stop(struct seq_file *seq, void *v)
2812{
2813 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo;
2814 struct tcp_iter_state *st = seq->private;
2815
2816 switch (st->state) {
2817 case TCP_SEQ_STATE_LISTENING:
2818 if (v != SEQ_START_TOKEN)
2819 spin_unlock(&hinfo->lhash2[st->bucket].lock);
2820 break;
2821 case TCP_SEQ_STATE_ESTABLISHED:
2822 if (v)
2823 spin_unlock_bh(inet_ehash_lockp(hinfo, st->bucket));
2824 break;
2825 }
2826}
2827EXPORT_SYMBOL(tcp_seq_stop);
2828
2829static void get_openreq4(const struct request_sock *req,
2830 struct seq_file *f, int i)
2831{
2832 const struct inet_request_sock *ireq = inet_rsk(req);
2833 long delta = req->rsk_timer.expires - jiffies;
2834
2835 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2836 " %02X %08X:%08X %02X:%08lX %08X %5u %8d %u %d %pK",
2837 i,
2838 ireq->ir_loc_addr,
2839 ireq->ir_num,
2840 ireq->ir_rmt_addr,
2841 ntohs(ireq->ir_rmt_port),
2842 TCP_SYN_RECV,
2843 0, 0, /* could print option size, but that is af dependent. */
2844 1, /* timers active (only the expire timer) */
2845 jiffies_delta_to_clock_t(delta),
2846 req->num_timeout,
2847 from_kuid_munged(seq_user_ns(f),
2848 sock_i_uid(req->rsk_listener)),
2849 0, /* non standard timer */
2850 0, /* open_requests have no inode */
2851 0,
2852 req);
2853}
2854
2855static void get_tcp4_sock(struct sock *sk, struct seq_file *f, int i)
2856{
2857 int timer_active;
2858 unsigned long timer_expires;
2859 const struct tcp_sock *tp = tcp_sk(sk);
2860 const struct inet_connection_sock *icsk = inet_csk(sk);
2861 const struct inet_sock *inet = inet_sk(sk);
2862 const struct fastopen_queue *fastopenq = &icsk->icsk_accept_queue.fastopenq;
2863 __be32 dest = inet->inet_daddr;
2864 __be32 src = inet->inet_rcv_saddr;
2865 __u16 destp = ntohs(inet->inet_dport);
2866 __u16 srcp = ntohs(inet->inet_sport);
2867 int rx_queue;
2868 int state;
2869
2870 if (icsk->icsk_pending == ICSK_TIME_RETRANS ||
2871 icsk->icsk_pending == ICSK_TIME_REO_TIMEOUT ||
2872 icsk->icsk_pending == ICSK_TIME_LOSS_PROBE) {
2873 timer_active = 1;
2874 timer_expires = icsk->icsk_timeout;
2875 } else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
2876 timer_active = 4;
2877 timer_expires = icsk->icsk_timeout;
2878 } else if (timer_pending(&sk->sk_timer)) {
2879 timer_active = 2;
2880 timer_expires = sk->sk_timer.expires;
2881 } else {
2882 timer_active = 0;
2883 timer_expires = jiffies;
2884 }
2885
2886 state = inet_sk_state_load(sk);
2887 if (state == TCP_LISTEN)
2888 rx_queue = READ_ONCE(sk->sk_ack_backlog);
2889 else
2890 /* Because we don't lock the socket,
2891 * we might find a transient negative value.
2892 */
2893 rx_queue = max_t(int, READ_ONCE(tp->rcv_nxt) -
2894 READ_ONCE(tp->copied_seq), 0);
2895
2896 seq_printf(f, "%4d: %08X:%04X %08X:%04X %02X %08X:%08X %02X:%08lX "
2897 "%08X %5u %8d %lu %d %pK %lu %lu %u %u %d",
2898 i, src, srcp, dest, destp, state,
2899 READ_ONCE(tp->write_seq) - tp->snd_una,
2900 rx_queue,
2901 timer_active,
2902 jiffies_delta_to_clock_t(timer_expires - jiffies),
2903 icsk->icsk_retransmits,
2904 from_kuid_munged(seq_user_ns(f), sock_i_uid(sk)),
2905 icsk->icsk_probes_out,
2906 sock_i_ino(sk),
2907 refcount_read(&sk->sk_refcnt), sk,
2908 jiffies_to_clock_t(icsk->icsk_rto),
2909 jiffies_to_clock_t(icsk->icsk_ack.ato),
2910 (icsk->icsk_ack.quick << 1) | inet_csk_in_pingpong_mode(sk),
2911 tcp_snd_cwnd(tp),
2912 state == TCP_LISTEN ?
2913 fastopenq->max_qlen :
2914 (tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh));
2915}
2916
2917static void get_timewait4_sock(const struct inet_timewait_sock *tw,
2918 struct seq_file *f, int i)
2919{
2920 long delta = tw->tw_timer.expires - jiffies;
2921 __be32 dest, src;
2922 __u16 destp, srcp;
2923
2924 dest = tw->tw_daddr;
2925 src = tw->tw_rcv_saddr;
2926 destp = ntohs(tw->tw_dport);
2927 srcp = ntohs(tw->tw_sport);
2928
2929 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2930 " %02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK",
2931 i, src, srcp, dest, destp, tw->tw_substate, 0, 0,
2932 3, jiffies_delta_to_clock_t(delta), 0, 0, 0, 0,
2933 refcount_read(&tw->tw_refcnt), tw);
2934}
2935
2936#define TMPSZ 150
2937
2938static int tcp4_seq_show(struct seq_file *seq, void *v)
2939{
2940 struct tcp_iter_state *st;
2941 struct sock *sk = v;
2942
2943 seq_setwidth(seq, TMPSZ - 1);
2944 if (v == SEQ_START_TOKEN) {
2945 seq_puts(seq, " sl local_address rem_address st tx_queue "
2946 "rx_queue tr tm->when retrnsmt uid timeout "
2947 "inode");
2948 goto out;
2949 }
2950 st = seq->private;
2951
2952 if (sk->sk_state == TCP_TIME_WAIT)
2953 get_timewait4_sock(v, seq, st->num);
2954 else if (sk->sk_state == TCP_NEW_SYN_RECV)
2955 get_openreq4(v, seq, st->num);
2956 else
2957 get_tcp4_sock(v, seq, st->num);
2958out:
2959 seq_pad(seq, '\n');
2960 return 0;
2961}
2962
2963#ifdef CONFIG_BPF_SYSCALL
2964struct bpf_tcp_iter_state {
2965 struct tcp_iter_state state;
2966 unsigned int cur_sk;
2967 unsigned int end_sk;
2968 unsigned int max_sk;
2969 struct sock **batch;
2970 bool st_bucket_done;
2971};
2972
2973struct bpf_iter__tcp {
2974 __bpf_md_ptr(struct bpf_iter_meta *, meta);
2975 __bpf_md_ptr(struct sock_common *, sk_common);
2976 uid_t uid __aligned(8);
2977};
2978
2979static int tcp_prog_seq_show(struct bpf_prog *prog, struct bpf_iter_meta *meta,
2980 struct sock_common *sk_common, uid_t uid)
2981{
2982 struct bpf_iter__tcp ctx;
2983
2984 meta->seq_num--; /* skip SEQ_START_TOKEN */
2985 ctx.meta = meta;
2986 ctx.sk_common = sk_common;
2987 ctx.uid = uid;
2988 return bpf_iter_run_prog(prog, &ctx);
2989}
2990
2991static void bpf_iter_tcp_put_batch(struct bpf_tcp_iter_state *iter)
2992{
2993 while (iter->cur_sk < iter->end_sk)
2994 sock_gen_put(iter->batch[iter->cur_sk++]);
2995}
2996
2997static int bpf_iter_tcp_realloc_batch(struct bpf_tcp_iter_state *iter,
2998 unsigned int new_batch_sz)
2999{
3000 struct sock **new_batch;
3001
3002 new_batch = kvmalloc(sizeof(*new_batch) * new_batch_sz,
3003 GFP_USER | __GFP_NOWARN);
3004 if (!new_batch)
3005 return -ENOMEM;
3006
3007 bpf_iter_tcp_put_batch(iter);
3008 kvfree(iter->batch);
3009 iter->batch = new_batch;
3010 iter->max_sk = new_batch_sz;
3011
3012 return 0;
3013}
3014
3015static unsigned int bpf_iter_tcp_listening_batch(struct seq_file *seq,
3016 struct sock *start_sk)
3017{
3018 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo;
3019 struct bpf_tcp_iter_state *iter = seq->private;
3020 struct tcp_iter_state *st = &iter->state;
3021 struct hlist_nulls_node *node;
3022 unsigned int expected = 1;
3023 struct sock *sk;
3024
3025 sock_hold(start_sk);
3026 iter->batch[iter->end_sk++] = start_sk;
3027
3028 sk = sk_nulls_next(start_sk);
3029 sk_nulls_for_each_from(sk, node) {
3030 if (seq_sk_match(seq, sk)) {
3031 if (iter->end_sk < iter->max_sk) {
3032 sock_hold(sk);
3033 iter->batch[iter->end_sk++] = sk;
3034 }
3035 expected++;
3036 }
3037 }
3038 spin_unlock(&hinfo->lhash2[st->bucket].lock);
3039
3040 return expected;
3041}
3042
3043static unsigned int bpf_iter_tcp_established_batch(struct seq_file *seq,
3044 struct sock *start_sk)
3045{
3046 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo;
3047 struct bpf_tcp_iter_state *iter = seq->private;
3048 struct tcp_iter_state *st = &iter->state;
3049 struct hlist_nulls_node *node;
3050 unsigned int expected = 1;
3051 struct sock *sk;
3052
3053 sock_hold(start_sk);
3054 iter->batch[iter->end_sk++] = start_sk;
3055
3056 sk = sk_nulls_next(start_sk);
3057 sk_nulls_for_each_from(sk, node) {
3058 if (seq_sk_match(seq, sk)) {
3059 if (iter->end_sk < iter->max_sk) {
3060 sock_hold(sk);
3061 iter->batch[iter->end_sk++] = sk;
3062 }
3063 expected++;
3064 }
3065 }
3066 spin_unlock_bh(inet_ehash_lockp(hinfo, st->bucket));
3067
3068 return expected;
3069}
3070
3071static struct sock *bpf_iter_tcp_batch(struct seq_file *seq)
3072{
3073 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo;
3074 struct bpf_tcp_iter_state *iter = seq->private;
3075 struct tcp_iter_state *st = &iter->state;
3076 unsigned int expected;
3077 bool resized = false;
3078 struct sock *sk;
3079
3080 /* The st->bucket is done. Directly advance to the next
3081 * bucket instead of having the tcp_seek_last_pos() to skip
3082 * one by one in the current bucket and eventually find out
3083 * it has to advance to the next bucket.
3084 */
3085 if (iter->st_bucket_done) {
3086 st->offset = 0;
3087 st->bucket++;
3088 if (st->state == TCP_SEQ_STATE_LISTENING &&
3089 st->bucket > hinfo->lhash2_mask) {
3090 st->state = TCP_SEQ_STATE_ESTABLISHED;
3091 st->bucket = 0;
3092 }
3093 }
3094
3095again:
3096 /* Get a new batch */
3097 iter->cur_sk = 0;
3098 iter->end_sk = 0;
3099 iter->st_bucket_done = false;
3100
3101 sk = tcp_seek_last_pos(seq);
3102 if (!sk)
3103 return NULL; /* Done */
3104
3105 if (st->state == TCP_SEQ_STATE_LISTENING)
3106 expected = bpf_iter_tcp_listening_batch(seq, sk);
3107 else
3108 expected = bpf_iter_tcp_established_batch(seq, sk);
3109
3110 if (iter->end_sk == expected) {
3111 iter->st_bucket_done = true;
3112 return sk;
3113 }
3114
3115 if (!resized && !bpf_iter_tcp_realloc_batch(iter, expected * 3 / 2)) {
3116 resized = true;
3117 goto again;
3118 }
3119
3120 return sk;
3121}
3122
3123static void *bpf_iter_tcp_seq_start(struct seq_file *seq, loff_t *pos)
3124{
3125 /* bpf iter does not support lseek, so it always
3126 * continue from where it was stop()-ped.
3127 */
3128 if (*pos)
3129 return bpf_iter_tcp_batch(seq);
3130
3131 return SEQ_START_TOKEN;
3132}
3133
3134static void *bpf_iter_tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
3135{
3136 struct bpf_tcp_iter_state *iter = seq->private;
3137 struct tcp_iter_state *st = &iter->state;
3138 struct sock *sk;
3139
3140 /* Whenever seq_next() is called, the iter->cur_sk is
3141 * done with seq_show(), so advance to the next sk in
3142 * the batch.
3143 */
3144 if (iter->cur_sk < iter->end_sk) {
3145 /* Keeping st->num consistent in tcp_iter_state.
3146 * bpf_iter_tcp does not use st->num.
3147 * meta.seq_num is used instead.
3148 */
3149 st->num++;
3150 /* Move st->offset to the next sk in the bucket such that
3151 * the future start() will resume at st->offset in
3152 * st->bucket. See tcp_seek_last_pos().
3153 */
3154 st->offset++;
3155 sock_gen_put(iter->batch[iter->cur_sk++]);
3156 }
3157
3158 if (iter->cur_sk < iter->end_sk)
3159 sk = iter->batch[iter->cur_sk];
3160 else
3161 sk = bpf_iter_tcp_batch(seq);
3162
3163 ++*pos;
3164 /* Keeping st->last_pos consistent in tcp_iter_state.
3165 * bpf iter does not do lseek, so st->last_pos always equals to *pos.
3166 */
3167 st->last_pos = *pos;
3168 return sk;
3169}
3170
3171static int bpf_iter_tcp_seq_show(struct seq_file *seq, void *v)
3172{
3173 struct bpf_iter_meta meta;
3174 struct bpf_prog *prog;
3175 struct sock *sk = v;
3176 uid_t uid;
3177 int ret;
3178
3179 if (v == SEQ_START_TOKEN)
3180 return 0;
3181
3182 if (sk_fullsock(sk))
3183 lock_sock(sk);
3184
3185 if (unlikely(sk_unhashed(sk))) {
3186 ret = SEQ_SKIP;
3187 goto unlock;
3188 }
3189
3190 if (sk->sk_state == TCP_TIME_WAIT) {
3191 uid = 0;
3192 } else if (sk->sk_state == TCP_NEW_SYN_RECV) {
3193 const struct request_sock *req = v;
3194
3195 uid = from_kuid_munged(seq_user_ns(seq),
3196 sock_i_uid(req->rsk_listener));
3197 } else {
3198 uid = from_kuid_munged(seq_user_ns(seq), sock_i_uid(sk));
3199 }
3200
3201 meta.seq = seq;
3202 prog = bpf_iter_get_info(&meta, false);
3203 ret = tcp_prog_seq_show(prog, &meta, v, uid);
3204
3205unlock:
3206 if (sk_fullsock(sk))
3207 release_sock(sk);
3208 return ret;
3209
3210}
3211
3212static void bpf_iter_tcp_seq_stop(struct seq_file *seq, void *v)
3213{
3214 struct bpf_tcp_iter_state *iter = seq->private;
3215 struct bpf_iter_meta meta;
3216 struct bpf_prog *prog;
3217
3218 if (!v) {
3219 meta.seq = seq;
3220 prog = bpf_iter_get_info(&meta, true);
3221 if (prog)
3222 (void)tcp_prog_seq_show(prog, &meta, v, 0);
3223 }
3224
3225 if (iter->cur_sk < iter->end_sk) {
3226 bpf_iter_tcp_put_batch(iter);
3227 iter->st_bucket_done = false;
3228 }
3229}
3230
3231static const struct seq_operations bpf_iter_tcp_seq_ops = {
3232 .show = bpf_iter_tcp_seq_show,
3233 .start = bpf_iter_tcp_seq_start,
3234 .next = bpf_iter_tcp_seq_next,
3235 .stop = bpf_iter_tcp_seq_stop,
3236};
3237#endif
3238static unsigned short seq_file_family(const struct seq_file *seq)
3239{
3240 const struct tcp_seq_afinfo *afinfo;
3241
3242#ifdef CONFIG_BPF_SYSCALL
3243 /* Iterated from bpf_iter. Let the bpf prog to filter instead. */
3244 if (seq->op == &bpf_iter_tcp_seq_ops)
3245 return AF_UNSPEC;
3246#endif
3247
3248 /* Iterated from proc fs */
3249 afinfo = pde_data(file_inode(seq->file));
3250 return afinfo->family;
3251}
3252
3253static const struct seq_operations tcp4_seq_ops = {
3254 .show = tcp4_seq_show,
3255 .start = tcp_seq_start,
3256 .next = tcp_seq_next,
3257 .stop = tcp_seq_stop,
3258};
3259
3260static struct tcp_seq_afinfo tcp4_seq_afinfo = {
3261 .family = AF_INET,
3262};
3263
3264static int __net_init tcp4_proc_init_net(struct net *net)
3265{
3266 if (!proc_create_net_data("tcp", 0444, net->proc_net, &tcp4_seq_ops,
3267 sizeof(struct tcp_iter_state), &tcp4_seq_afinfo))
3268 return -ENOMEM;
3269 return 0;
3270}
3271
3272static void __net_exit tcp4_proc_exit_net(struct net *net)
3273{
3274 remove_proc_entry("tcp", net->proc_net);
3275}
3276
3277static struct pernet_operations tcp4_net_ops = {
3278 .init = tcp4_proc_init_net,
3279 .exit = tcp4_proc_exit_net,
3280};
3281
3282int __init tcp4_proc_init(void)
3283{
3284 return register_pernet_subsys(&tcp4_net_ops);
3285}
3286
3287void tcp4_proc_exit(void)
3288{
3289 unregister_pernet_subsys(&tcp4_net_ops);
3290}
3291#endif /* CONFIG_PROC_FS */
3292
3293/* @wake is one when sk_stream_write_space() calls us.
3294 * This sends EPOLLOUT only if notsent_bytes is half the limit.
3295 * This mimics the strategy used in sock_def_write_space().
3296 */
3297bool tcp_stream_memory_free(const struct sock *sk, int wake)
3298{
3299 const struct tcp_sock *tp = tcp_sk(sk);
3300 u32 notsent_bytes = READ_ONCE(tp->write_seq) -
3301 READ_ONCE(tp->snd_nxt);
3302
3303 return (notsent_bytes << wake) < tcp_notsent_lowat(tp);
3304}
3305EXPORT_SYMBOL(tcp_stream_memory_free);
3306
3307struct proto tcp_prot = {
3308 .name = "TCP",
3309 .owner = THIS_MODULE,
3310 .close = tcp_close,
3311 .pre_connect = tcp_v4_pre_connect,
3312 .connect = tcp_v4_connect,
3313 .disconnect = tcp_disconnect,
3314 .accept = inet_csk_accept,
3315 .ioctl = tcp_ioctl,
3316 .init = tcp_v4_init_sock,
3317 .destroy = tcp_v4_destroy_sock,
3318 .shutdown = tcp_shutdown,
3319 .setsockopt = tcp_setsockopt,
3320 .getsockopt = tcp_getsockopt,
3321 .bpf_bypass_getsockopt = tcp_bpf_bypass_getsockopt,
3322 .keepalive = tcp_set_keepalive,
3323 .recvmsg = tcp_recvmsg,
3324 .sendmsg = tcp_sendmsg,
3325 .splice_eof = tcp_splice_eof,
3326 .backlog_rcv = tcp_v4_do_rcv,
3327 .release_cb = tcp_release_cb,
3328 .hash = inet_hash,
3329 .unhash = inet_unhash,
3330 .get_port = inet_csk_get_port,
3331 .put_port = inet_put_port,
3332#ifdef CONFIG_BPF_SYSCALL
3333 .psock_update_sk_prot = tcp_bpf_update_proto,
3334#endif
3335 .enter_memory_pressure = tcp_enter_memory_pressure,
3336 .leave_memory_pressure = tcp_leave_memory_pressure,
3337 .stream_memory_free = tcp_stream_memory_free,
3338 .sockets_allocated = &tcp_sockets_allocated,
3339 .orphan_count = &tcp_orphan_count,
3340
3341 .memory_allocated = &tcp_memory_allocated,
3342 .per_cpu_fw_alloc = &tcp_memory_per_cpu_fw_alloc,
3343
3344 .memory_pressure = &tcp_memory_pressure,
3345 .sysctl_mem = sysctl_tcp_mem,
3346 .sysctl_wmem_offset = offsetof(struct net, ipv4.sysctl_tcp_wmem),
3347 .sysctl_rmem_offset = offsetof(struct net, ipv4.sysctl_tcp_rmem),
3348 .max_header = MAX_TCP_HEADER,
3349 .obj_size = sizeof(struct tcp_sock),
3350 .slab_flags = SLAB_TYPESAFE_BY_RCU,
3351 .twsk_prot = &tcp_timewait_sock_ops,
3352 .rsk_prot = &tcp_request_sock_ops,
3353 .h.hashinfo = NULL,
3354 .no_autobind = true,
3355 .diag_destroy = tcp_abort,
3356};
3357EXPORT_SYMBOL(tcp_prot);
3358
3359static void __net_exit tcp_sk_exit(struct net *net)
3360{
3361 if (net->ipv4.tcp_congestion_control)
3362 bpf_module_put(net->ipv4.tcp_congestion_control,
3363 net->ipv4.tcp_congestion_control->owner);
3364}
3365
3366static void __net_init tcp_set_hashinfo(struct net *net)
3367{
3368 struct inet_hashinfo *hinfo;
3369 unsigned int ehash_entries;
3370 struct net *old_net;
3371
3372 if (net_eq(net, &init_net))
3373 goto fallback;
3374
3375 old_net = current->nsproxy->net_ns;
3376 ehash_entries = READ_ONCE(old_net->ipv4.sysctl_tcp_child_ehash_entries);
3377 if (!ehash_entries)
3378 goto fallback;
3379
3380 ehash_entries = roundup_pow_of_two(ehash_entries);
3381 hinfo = inet_pernet_hashinfo_alloc(&tcp_hashinfo, ehash_entries);
3382 if (!hinfo) {
3383 pr_warn("Failed to allocate TCP ehash (entries: %u) "
3384 "for a netns, fallback to the global one\n",
3385 ehash_entries);
3386fallback:
3387 hinfo = &tcp_hashinfo;
3388 ehash_entries = tcp_hashinfo.ehash_mask + 1;
3389 }
3390
3391 net->ipv4.tcp_death_row.hashinfo = hinfo;
3392 net->ipv4.tcp_death_row.sysctl_max_tw_buckets = ehash_entries / 2;
3393 net->ipv4.sysctl_max_syn_backlog = max(128U, ehash_entries / 128);
3394}
3395
3396static int __net_init tcp_sk_init(struct net *net)
3397{
3398 net->ipv4.sysctl_tcp_ecn = 2;
3399 net->ipv4.sysctl_tcp_ecn_fallback = 1;
3400
3401 net->ipv4.sysctl_tcp_base_mss = TCP_BASE_MSS;
3402 net->ipv4.sysctl_tcp_min_snd_mss = TCP_MIN_SND_MSS;
3403 net->ipv4.sysctl_tcp_probe_threshold = TCP_PROBE_THRESHOLD;
3404 net->ipv4.sysctl_tcp_probe_interval = TCP_PROBE_INTERVAL;
3405 net->ipv4.sysctl_tcp_mtu_probe_floor = TCP_MIN_SND_MSS;
3406
3407 net->ipv4.sysctl_tcp_keepalive_time = TCP_KEEPALIVE_TIME;
3408 net->ipv4.sysctl_tcp_keepalive_probes = TCP_KEEPALIVE_PROBES;
3409 net->ipv4.sysctl_tcp_keepalive_intvl = TCP_KEEPALIVE_INTVL;
3410
3411 net->ipv4.sysctl_tcp_syn_retries = TCP_SYN_RETRIES;
3412 net->ipv4.sysctl_tcp_synack_retries = TCP_SYNACK_RETRIES;
3413 net->ipv4.sysctl_tcp_syncookies = 1;
3414 net->ipv4.sysctl_tcp_reordering = TCP_FASTRETRANS_THRESH;
3415 net->ipv4.sysctl_tcp_retries1 = TCP_RETR1;
3416 net->ipv4.sysctl_tcp_retries2 = TCP_RETR2;
3417 net->ipv4.sysctl_tcp_orphan_retries = 0;
3418 net->ipv4.sysctl_tcp_fin_timeout = TCP_FIN_TIMEOUT;
3419 net->ipv4.sysctl_tcp_notsent_lowat = UINT_MAX;
3420 net->ipv4.sysctl_tcp_tw_reuse = 2;
3421 net->ipv4.sysctl_tcp_no_ssthresh_metrics_save = 1;
3422
3423 refcount_set(&net->ipv4.tcp_death_row.tw_refcount, 1);
3424 tcp_set_hashinfo(net);
3425
3426 net->ipv4.sysctl_tcp_sack = 1;
3427 net->ipv4.sysctl_tcp_window_scaling = 1;
3428 net->ipv4.sysctl_tcp_timestamps = 1;
3429 net->ipv4.sysctl_tcp_early_retrans = 3;
3430 net->ipv4.sysctl_tcp_recovery = TCP_RACK_LOSS_DETECTION;
3431 net->ipv4.sysctl_tcp_slow_start_after_idle = 1; /* By default, RFC2861 behavior. */
3432 net->ipv4.sysctl_tcp_retrans_collapse = 1;
3433 net->ipv4.sysctl_tcp_max_reordering = 300;
3434 net->ipv4.sysctl_tcp_dsack = 1;
3435 net->ipv4.sysctl_tcp_app_win = 31;
3436 net->ipv4.sysctl_tcp_adv_win_scale = 1;
3437 net->ipv4.sysctl_tcp_frto = 2;
3438 net->ipv4.sysctl_tcp_moderate_rcvbuf = 1;
3439 /* This limits the percentage of the congestion window which we
3440 * will allow a single TSO frame to consume. Building TSO frames
3441 * which are too large can cause TCP streams to be bursty.
3442 */
3443 net->ipv4.sysctl_tcp_tso_win_divisor = 3;
3444 /* Default TSQ limit of 16 TSO segments */
3445 net->ipv4.sysctl_tcp_limit_output_bytes = 16 * 65536;
3446
3447 /* rfc5961 challenge ack rate limiting, per net-ns, disabled by default. */
3448 net->ipv4.sysctl_tcp_challenge_ack_limit = INT_MAX;
3449
3450 net->ipv4.sysctl_tcp_min_tso_segs = 2;
3451 net->ipv4.sysctl_tcp_tso_rtt_log = 9; /* 2^9 = 512 usec */
3452 net->ipv4.sysctl_tcp_min_rtt_wlen = 300;
3453 net->ipv4.sysctl_tcp_autocorking = 1;
3454 net->ipv4.sysctl_tcp_invalid_ratelimit = HZ/2;
3455 net->ipv4.sysctl_tcp_pacing_ss_ratio = 200;
3456 net->ipv4.sysctl_tcp_pacing_ca_ratio = 120;
3457 if (net != &init_net) {
3458 memcpy(net->ipv4.sysctl_tcp_rmem,
3459 init_net.ipv4.sysctl_tcp_rmem,
3460 sizeof(init_net.ipv4.sysctl_tcp_rmem));
3461 memcpy(net->ipv4.sysctl_tcp_wmem,
3462 init_net.ipv4.sysctl_tcp_wmem,
3463 sizeof(init_net.ipv4.sysctl_tcp_wmem));
3464 }
3465 net->ipv4.sysctl_tcp_comp_sack_delay_ns = NSEC_PER_MSEC;
3466 net->ipv4.sysctl_tcp_comp_sack_slack_ns = 100 * NSEC_PER_USEC;
3467 net->ipv4.sysctl_tcp_comp_sack_nr = 44;
3468 net->ipv4.sysctl_tcp_backlog_ack_defer = 1;
3469 net->ipv4.sysctl_tcp_fastopen = TFO_CLIENT_ENABLE;
3470 net->ipv4.sysctl_tcp_fastopen_blackhole_timeout = 0;
3471 atomic_set(&net->ipv4.tfo_active_disable_times, 0);
3472
3473 /* Set default values for PLB */
3474 net->ipv4.sysctl_tcp_plb_enabled = 0; /* Disabled by default */
3475 net->ipv4.sysctl_tcp_plb_idle_rehash_rounds = 3;
3476 net->ipv4.sysctl_tcp_plb_rehash_rounds = 12;
3477 net->ipv4.sysctl_tcp_plb_suspend_rto_sec = 60;
3478 /* Default congestion threshold for PLB to mark a round is 50% */
3479 net->ipv4.sysctl_tcp_plb_cong_thresh = (1 << TCP_PLB_SCALE) / 2;
3480
3481 /* Reno is always built in */
3482 if (!net_eq(net, &init_net) &&
3483 bpf_try_module_get(init_net.ipv4.tcp_congestion_control,
3484 init_net.ipv4.tcp_congestion_control->owner))
3485 net->ipv4.tcp_congestion_control = init_net.ipv4.tcp_congestion_control;
3486 else
3487 net->ipv4.tcp_congestion_control = &tcp_reno;
3488
3489 net->ipv4.sysctl_tcp_syn_linear_timeouts = 4;
3490 net->ipv4.sysctl_tcp_shrink_window = 0;
3491
3492 net->ipv4.sysctl_tcp_pingpong_thresh = 1;
3493
3494 return 0;
3495}
3496
3497static void __net_exit tcp_sk_exit_batch(struct list_head *net_exit_list)
3498{
3499 struct net *net;
3500
3501 tcp_twsk_purge(net_exit_list, AF_INET);
3502
3503 list_for_each_entry(net, net_exit_list, exit_list) {
3504 inet_pernet_hashinfo_free(net->ipv4.tcp_death_row.hashinfo);
3505 WARN_ON_ONCE(!refcount_dec_and_test(&net->ipv4.tcp_death_row.tw_refcount));
3506 tcp_fastopen_ctx_destroy(net);
3507 }
3508}
3509
3510static struct pernet_operations __net_initdata tcp_sk_ops = {
3511 .init = tcp_sk_init,
3512 .exit = tcp_sk_exit,
3513 .exit_batch = tcp_sk_exit_batch,
3514};
3515
3516#if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS)
3517DEFINE_BPF_ITER_FUNC(tcp, struct bpf_iter_meta *meta,
3518 struct sock_common *sk_common, uid_t uid)
3519
3520#define INIT_BATCH_SZ 16
3521
3522static int bpf_iter_init_tcp(void *priv_data, struct bpf_iter_aux_info *aux)
3523{
3524 struct bpf_tcp_iter_state *iter = priv_data;
3525 int err;
3526
3527 err = bpf_iter_init_seq_net(priv_data, aux);
3528 if (err)
3529 return err;
3530
3531 err = bpf_iter_tcp_realloc_batch(iter, INIT_BATCH_SZ);
3532 if (err) {
3533 bpf_iter_fini_seq_net(priv_data);
3534 return err;
3535 }
3536
3537 return 0;
3538}
3539
3540static void bpf_iter_fini_tcp(void *priv_data)
3541{
3542 struct bpf_tcp_iter_state *iter = priv_data;
3543
3544 bpf_iter_fini_seq_net(priv_data);
3545 kvfree(iter->batch);
3546}
3547
3548static const struct bpf_iter_seq_info tcp_seq_info = {
3549 .seq_ops = &bpf_iter_tcp_seq_ops,
3550 .init_seq_private = bpf_iter_init_tcp,
3551 .fini_seq_private = bpf_iter_fini_tcp,
3552 .seq_priv_size = sizeof(struct bpf_tcp_iter_state),
3553};
3554
3555static const struct bpf_func_proto *
3556bpf_iter_tcp_get_func_proto(enum bpf_func_id func_id,
3557 const struct bpf_prog *prog)
3558{
3559 switch (func_id) {
3560 case BPF_FUNC_setsockopt:
3561 return &bpf_sk_setsockopt_proto;
3562 case BPF_FUNC_getsockopt:
3563 return &bpf_sk_getsockopt_proto;
3564 default:
3565 return NULL;
3566 }
3567}
3568
3569static struct bpf_iter_reg tcp_reg_info = {
3570 .target = "tcp",
3571 .ctx_arg_info_size = 1,
3572 .ctx_arg_info = {
3573 { offsetof(struct bpf_iter__tcp, sk_common),
3574 PTR_TO_BTF_ID_OR_NULL | PTR_TRUSTED },
3575 },
3576 .get_func_proto = bpf_iter_tcp_get_func_proto,
3577 .seq_info = &tcp_seq_info,
3578};
3579
3580static void __init bpf_iter_register(void)
3581{
3582 tcp_reg_info.ctx_arg_info[0].btf_id = btf_sock_ids[BTF_SOCK_TYPE_SOCK_COMMON];
3583 if (bpf_iter_reg_target(&tcp_reg_info))
3584 pr_warn("Warning: could not register bpf iterator tcp\n");
3585}
3586
3587#endif
3588
3589void __init tcp_v4_init(void)
3590{
3591 int cpu, res;
3592
3593 for_each_possible_cpu(cpu) {
3594 struct sock *sk;
3595
3596 res = inet_ctl_sock_create(&sk, PF_INET, SOCK_RAW,
3597 IPPROTO_TCP, &init_net);
3598 if (res)
3599 panic("Failed to create the TCP control socket.\n");
3600 sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
3601
3602 /* Please enforce IP_DF and IPID==0 for RST and
3603 * ACK sent in SYN-RECV and TIME-WAIT state.
3604 */
3605 inet_sk(sk)->pmtudisc = IP_PMTUDISC_DO;
3606
3607 per_cpu(ipv4_tcp_sk, cpu) = sk;
3608 }
3609 if (register_pernet_subsys(&tcp_sk_ops))
3610 panic("Failed to create the TCP control socket.\n");
3611
3612#if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS)
3613 bpf_iter_register();
3614#endif
3615}