Loading...
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * INET An implementation of the TCP/IP protocol suite for the LINUX
4 * operating system. INET is implemented using the BSD Socket
5 * interface as the means of communication with the user level.
6 *
7 * Implementation of the Transmission Control Protocol(TCP).
8 *
9 * IPv4 specific functions
10 *
11 * code split from:
12 * linux/ipv4/tcp.c
13 * linux/ipv4/tcp_input.c
14 * linux/ipv4/tcp_output.c
15 *
16 * See tcp.c for author information
17 */
18
19/*
20 * Changes:
21 * David S. Miller : New socket lookup architecture.
22 * This code is dedicated to John Dyson.
23 * David S. Miller : Change semantics of established hash,
24 * half is devoted to TIME_WAIT sockets
25 * and the rest go in the other half.
26 * Andi Kleen : Add support for syncookies and fixed
27 * some bugs: ip options weren't passed to
28 * the TCP layer, missed a check for an
29 * ACK bit.
30 * Andi Kleen : Implemented fast path mtu discovery.
31 * Fixed many serious bugs in the
32 * request_sock handling and moved
33 * most of it into the af independent code.
34 * Added tail drop and some other bugfixes.
35 * Added new listen semantics.
36 * Mike McLagan : Routing by source
37 * Juan Jose Ciarlante: ip_dynaddr bits
38 * Andi Kleen: various fixes.
39 * Vitaly E. Lavrov : Transparent proxy revived after year
40 * coma.
41 * Andi Kleen : Fix new listen.
42 * Andi Kleen : Fix accept error reporting.
43 * YOSHIFUJI Hideaki @USAGI and: Support IPV6_V6ONLY socket option, which
44 * Alexey Kuznetsov allow both IPv4 and IPv6 sockets to bind
45 * a single port at the same time.
46 */
47
48#define pr_fmt(fmt) "TCP: " fmt
49
50#include <linux/bottom_half.h>
51#include <linux/types.h>
52#include <linux/fcntl.h>
53#include <linux/module.h>
54#include <linux/random.h>
55#include <linux/cache.h>
56#include <linux/jhash.h>
57#include <linux/init.h>
58#include <linux/times.h>
59#include <linux/slab.h>
60
61#include <net/net_namespace.h>
62#include <net/icmp.h>
63#include <net/inet_hashtables.h>
64#include <net/tcp.h>
65#include <net/transp_v6.h>
66#include <net/ipv6.h>
67#include <net/inet_common.h>
68#include <net/timewait_sock.h>
69#include <net/xfrm.h>
70#include <net/secure_seq.h>
71#include <net/busy_poll.h>
72
73#include <linux/inet.h>
74#include <linux/ipv6.h>
75#include <linux/stddef.h>
76#include <linux/proc_fs.h>
77#include <linux/seq_file.h>
78#include <linux/inetdevice.h>
79#include <linux/btf_ids.h>
80
81#include <crypto/hash.h>
82#include <linux/scatterlist.h>
83
84#include <trace/events/tcp.h>
85
86#ifdef CONFIG_TCP_MD5SIG
87static int tcp_v4_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key,
88 __be32 daddr, __be32 saddr, const struct tcphdr *th);
89#endif
90
91struct inet_hashinfo tcp_hashinfo;
92EXPORT_SYMBOL(tcp_hashinfo);
93
94static u32 tcp_v4_init_seq(const struct sk_buff *skb)
95{
96 return secure_tcp_seq(ip_hdr(skb)->daddr,
97 ip_hdr(skb)->saddr,
98 tcp_hdr(skb)->dest,
99 tcp_hdr(skb)->source);
100}
101
102static u32 tcp_v4_init_ts_off(const struct net *net, const struct sk_buff *skb)
103{
104 return secure_tcp_ts_off(net, ip_hdr(skb)->daddr, ip_hdr(skb)->saddr);
105}
106
107int tcp_twsk_unique(struct sock *sk, struct sock *sktw, void *twp)
108{
109 const struct inet_timewait_sock *tw = inet_twsk(sktw);
110 const struct tcp_timewait_sock *tcptw = tcp_twsk(sktw);
111 struct tcp_sock *tp = tcp_sk(sk);
112 int reuse = sock_net(sk)->ipv4.sysctl_tcp_tw_reuse;
113
114 if (reuse == 2) {
115 /* Still does not detect *everything* that goes through
116 * lo, since we require a loopback src or dst address
117 * or direct binding to 'lo' interface.
118 */
119 bool loopback = false;
120 if (tw->tw_bound_dev_if == LOOPBACK_IFINDEX)
121 loopback = true;
122#if IS_ENABLED(CONFIG_IPV6)
123 if (tw->tw_family == AF_INET6) {
124 if (ipv6_addr_loopback(&tw->tw_v6_daddr) ||
125 ipv6_addr_v4mapped_loopback(&tw->tw_v6_daddr) ||
126 ipv6_addr_loopback(&tw->tw_v6_rcv_saddr) ||
127 ipv6_addr_v4mapped_loopback(&tw->tw_v6_rcv_saddr))
128 loopback = true;
129 } else
130#endif
131 {
132 if (ipv4_is_loopback(tw->tw_daddr) ||
133 ipv4_is_loopback(tw->tw_rcv_saddr))
134 loopback = true;
135 }
136 if (!loopback)
137 reuse = 0;
138 }
139
140 /* With PAWS, it is safe from the viewpoint
141 of data integrity. Even without PAWS it is safe provided sequence
142 spaces do not overlap i.e. at data rates <= 80Mbit/sec.
143
144 Actually, the idea is close to VJ's one, only timestamp cache is
145 held not per host, but per port pair and TW bucket is used as state
146 holder.
147
148 If TW bucket has been already destroyed we fall back to VJ's scheme
149 and use initial timestamp retrieved from peer table.
150 */
151 if (tcptw->tw_ts_recent_stamp &&
152 (!twp || (reuse && time_after32(ktime_get_seconds(),
153 tcptw->tw_ts_recent_stamp)))) {
154 /* In case of repair and re-using TIME-WAIT sockets we still
155 * want to be sure that it is safe as above but honor the
156 * sequence numbers and time stamps set as part of the repair
157 * process.
158 *
159 * Without this check re-using a TIME-WAIT socket with TCP
160 * repair would accumulate a -1 on the repair assigned
161 * sequence number. The first time it is reused the sequence
162 * is -1, the second time -2, etc. This fixes that issue
163 * without appearing to create any others.
164 */
165 if (likely(!tp->repair)) {
166 u32 seq = tcptw->tw_snd_nxt + 65535 + 2;
167
168 if (!seq)
169 seq = 1;
170 WRITE_ONCE(tp->write_seq, seq);
171 tp->rx_opt.ts_recent = tcptw->tw_ts_recent;
172 tp->rx_opt.ts_recent_stamp = tcptw->tw_ts_recent_stamp;
173 }
174 sock_hold(sktw);
175 return 1;
176 }
177
178 return 0;
179}
180EXPORT_SYMBOL_GPL(tcp_twsk_unique);
181
182static int tcp_v4_pre_connect(struct sock *sk, struct sockaddr *uaddr,
183 int addr_len)
184{
185 /* This check is replicated from tcp_v4_connect() and intended to
186 * prevent BPF program called below from accessing bytes that are out
187 * of the bound specified by user in addr_len.
188 */
189 if (addr_len < sizeof(struct sockaddr_in))
190 return -EINVAL;
191
192 sock_owned_by_me(sk);
193
194 return BPF_CGROUP_RUN_PROG_INET4_CONNECT(sk, uaddr);
195}
196
197/* This will initiate an outgoing connection. */
198int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
199{
200 struct sockaddr_in *usin = (struct sockaddr_in *)uaddr;
201 struct inet_sock *inet = inet_sk(sk);
202 struct tcp_sock *tp = tcp_sk(sk);
203 __be16 orig_sport, orig_dport;
204 __be32 daddr, nexthop;
205 struct flowi4 *fl4;
206 struct rtable *rt;
207 int err;
208 struct ip_options_rcu *inet_opt;
209 struct inet_timewait_death_row *tcp_death_row = &sock_net(sk)->ipv4.tcp_death_row;
210
211 if (addr_len < sizeof(struct sockaddr_in))
212 return -EINVAL;
213
214 if (usin->sin_family != AF_INET)
215 return -EAFNOSUPPORT;
216
217 nexthop = daddr = usin->sin_addr.s_addr;
218 inet_opt = rcu_dereference_protected(inet->inet_opt,
219 lockdep_sock_is_held(sk));
220 if (inet_opt && inet_opt->opt.srr) {
221 if (!daddr)
222 return -EINVAL;
223 nexthop = inet_opt->opt.faddr;
224 }
225
226 orig_sport = inet->inet_sport;
227 orig_dport = usin->sin_port;
228 fl4 = &inet->cork.fl.u.ip4;
229 rt = ip_route_connect(fl4, nexthop, inet->inet_saddr,
230 RT_CONN_FLAGS(sk), sk->sk_bound_dev_if,
231 IPPROTO_TCP,
232 orig_sport, orig_dport, sk);
233 if (IS_ERR(rt)) {
234 err = PTR_ERR(rt);
235 if (err == -ENETUNREACH)
236 IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTNOROUTES);
237 return err;
238 }
239
240 if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) {
241 ip_rt_put(rt);
242 return -ENETUNREACH;
243 }
244
245 if (!inet_opt || !inet_opt->opt.srr)
246 daddr = fl4->daddr;
247
248 if (!inet->inet_saddr)
249 inet->inet_saddr = fl4->saddr;
250 sk_rcv_saddr_set(sk, inet->inet_saddr);
251
252 if (tp->rx_opt.ts_recent_stamp && inet->inet_daddr != daddr) {
253 /* Reset inherited state */
254 tp->rx_opt.ts_recent = 0;
255 tp->rx_opt.ts_recent_stamp = 0;
256 if (likely(!tp->repair))
257 WRITE_ONCE(tp->write_seq, 0);
258 }
259
260 inet->inet_dport = usin->sin_port;
261 sk_daddr_set(sk, daddr);
262
263 inet_csk(sk)->icsk_ext_hdr_len = 0;
264 if (inet_opt)
265 inet_csk(sk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
266
267 tp->rx_opt.mss_clamp = TCP_MSS_DEFAULT;
268
269 /* Socket identity is still unknown (sport may be zero).
270 * However we set state to SYN-SENT and not releasing socket
271 * lock select source port, enter ourselves into the hash tables and
272 * complete initialization after this.
273 */
274 tcp_set_state(sk, TCP_SYN_SENT);
275 err = inet_hash_connect(tcp_death_row, sk);
276 if (err)
277 goto failure;
278
279 sk_set_txhash(sk);
280
281 rt = ip_route_newports(fl4, rt, orig_sport, orig_dport,
282 inet->inet_sport, inet->inet_dport, sk);
283 if (IS_ERR(rt)) {
284 err = PTR_ERR(rt);
285 rt = NULL;
286 goto failure;
287 }
288 /* OK, now commit destination to socket. */
289 sk->sk_gso_type = SKB_GSO_TCPV4;
290 sk_setup_caps(sk, &rt->dst);
291 rt = NULL;
292
293 if (likely(!tp->repair)) {
294 if (!tp->write_seq)
295 WRITE_ONCE(tp->write_seq,
296 secure_tcp_seq(inet->inet_saddr,
297 inet->inet_daddr,
298 inet->inet_sport,
299 usin->sin_port));
300 tp->tsoffset = secure_tcp_ts_off(sock_net(sk),
301 inet->inet_saddr,
302 inet->inet_daddr);
303 }
304
305 inet->inet_id = prandom_u32();
306
307 if (tcp_fastopen_defer_connect(sk, &err))
308 return err;
309 if (err)
310 goto failure;
311
312 err = tcp_connect(sk);
313
314 if (err)
315 goto failure;
316
317 return 0;
318
319failure:
320 /*
321 * This unhashes the socket and releases the local port,
322 * if necessary.
323 */
324 tcp_set_state(sk, TCP_CLOSE);
325 ip_rt_put(rt);
326 sk->sk_route_caps = 0;
327 inet->inet_dport = 0;
328 return err;
329}
330EXPORT_SYMBOL(tcp_v4_connect);
331
332/*
333 * This routine reacts to ICMP_FRAG_NEEDED mtu indications as defined in RFC1191.
334 * It can be called through tcp_release_cb() if socket was owned by user
335 * at the time tcp_v4_err() was called to handle ICMP message.
336 */
337void tcp_v4_mtu_reduced(struct sock *sk)
338{
339 struct inet_sock *inet = inet_sk(sk);
340 struct dst_entry *dst;
341 u32 mtu;
342
343 if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE))
344 return;
345 mtu = tcp_sk(sk)->mtu_info;
346 dst = inet_csk_update_pmtu(sk, mtu);
347 if (!dst)
348 return;
349
350 /* Something is about to be wrong... Remember soft error
351 * for the case, if this connection will not able to recover.
352 */
353 if (mtu < dst_mtu(dst) && ip_dont_fragment(sk, dst))
354 sk->sk_err_soft = EMSGSIZE;
355
356 mtu = dst_mtu(dst);
357
358 if (inet->pmtudisc != IP_PMTUDISC_DONT &&
359 ip_sk_accept_pmtu(sk) &&
360 inet_csk(sk)->icsk_pmtu_cookie > mtu) {
361 tcp_sync_mss(sk, mtu);
362
363 /* Resend the TCP packet because it's
364 * clear that the old packet has been
365 * dropped. This is the new "fast" path mtu
366 * discovery.
367 */
368 tcp_simple_retransmit(sk);
369 } /* else let the usual retransmit timer handle it */
370}
371EXPORT_SYMBOL(tcp_v4_mtu_reduced);
372
373static void do_redirect(struct sk_buff *skb, struct sock *sk)
374{
375 struct dst_entry *dst = __sk_dst_check(sk, 0);
376
377 if (dst)
378 dst->ops->redirect(dst, sk, skb);
379}
380
381
382/* handle ICMP messages on TCP_NEW_SYN_RECV request sockets */
383void tcp_req_err(struct sock *sk, u32 seq, bool abort)
384{
385 struct request_sock *req = inet_reqsk(sk);
386 struct net *net = sock_net(sk);
387
388 /* ICMPs are not backlogged, hence we cannot get
389 * an established socket here.
390 */
391 if (seq != tcp_rsk(req)->snt_isn) {
392 __NET_INC_STATS(net, LINUX_MIB_OUTOFWINDOWICMPS);
393 } else if (abort) {
394 /*
395 * Still in SYN_RECV, just remove it silently.
396 * There is no good way to pass the error to the newly
397 * created socket, and POSIX does not want network
398 * errors returned from accept().
399 */
400 inet_csk_reqsk_queue_drop(req->rsk_listener, req);
401 tcp_listendrop(req->rsk_listener);
402 }
403 reqsk_put(req);
404}
405EXPORT_SYMBOL(tcp_req_err);
406
407/* TCP-LD (RFC 6069) logic */
408void tcp_ld_RTO_revert(struct sock *sk, u32 seq)
409{
410 struct inet_connection_sock *icsk = inet_csk(sk);
411 struct tcp_sock *tp = tcp_sk(sk);
412 struct sk_buff *skb;
413 s32 remaining;
414 u32 delta_us;
415
416 if (sock_owned_by_user(sk))
417 return;
418
419 if (seq != tp->snd_una || !icsk->icsk_retransmits ||
420 !icsk->icsk_backoff)
421 return;
422
423 skb = tcp_rtx_queue_head(sk);
424 if (WARN_ON_ONCE(!skb))
425 return;
426
427 icsk->icsk_backoff--;
428 icsk->icsk_rto = tp->srtt_us ? __tcp_set_rto(tp) : TCP_TIMEOUT_INIT;
429 icsk->icsk_rto = inet_csk_rto_backoff(icsk, TCP_RTO_MAX);
430
431 tcp_mstamp_refresh(tp);
432 delta_us = (u32)(tp->tcp_mstamp - tcp_skb_timestamp_us(skb));
433 remaining = icsk->icsk_rto - usecs_to_jiffies(delta_us);
434
435 if (remaining > 0) {
436 inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
437 remaining, TCP_RTO_MAX);
438 } else {
439 /* RTO revert clocked out retransmission.
440 * Will retransmit now.
441 */
442 tcp_retransmit_timer(sk);
443 }
444}
445EXPORT_SYMBOL(tcp_ld_RTO_revert);
446
447/*
448 * This routine is called by the ICMP module when it gets some
449 * sort of error condition. If err < 0 then the socket should
450 * be closed and the error returned to the user. If err > 0
451 * it's just the icmp type << 8 | icmp code. After adjustment
452 * header points to the first 8 bytes of the tcp header. We need
453 * to find the appropriate port.
454 *
455 * The locking strategy used here is very "optimistic". When
456 * someone else accesses the socket the ICMP is just dropped
457 * and for some paths there is no check at all.
458 * A more general error queue to queue errors for later handling
459 * is probably better.
460 *
461 */
462
463int tcp_v4_err(struct sk_buff *skb, u32 info)
464{
465 const struct iphdr *iph = (const struct iphdr *)skb->data;
466 struct tcphdr *th = (struct tcphdr *)(skb->data + (iph->ihl << 2));
467 struct tcp_sock *tp;
468 struct inet_sock *inet;
469 const int type = icmp_hdr(skb)->type;
470 const int code = icmp_hdr(skb)->code;
471 struct sock *sk;
472 struct request_sock *fastopen;
473 u32 seq, snd_una;
474 int err;
475 struct net *net = dev_net(skb->dev);
476
477 sk = __inet_lookup_established(net, &tcp_hashinfo, iph->daddr,
478 th->dest, iph->saddr, ntohs(th->source),
479 inet_iif(skb), 0);
480 if (!sk) {
481 __ICMP_INC_STATS(net, ICMP_MIB_INERRORS);
482 return -ENOENT;
483 }
484 if (sk->sk_state == TCP_TIME_WAIT) {
485 inet_twsk_put(inet_twsk(sk));
486 return 0;
487 }
488 seq = ntohl(th->seq);
489 if (sk->sk_state == TCP_NEW_SYN_RECV) {
490 tcp_req_err(sk, seq, type == ICMP_PARAMETERPROB ||
491 type == ICMP_TIME_EXCEEDED ||
492 (type == ICMP_DEST_UNREACH &&
493 (code == ICMP_NET_UNREACH ||
494 code == ICMP_HOST_UNREACH)));
495 return 0;
496 }
497
498 bh_lock_sock(sk);
499 /* If too many ICMPs get dropped on busy
500 * servers this needs to be solved differently.
501 * We do take care of PMTU discovery (RFC1191) special case :
502 * we can receive locally generated ICMP messages while socket is held.
503 */
504 if (sock_owned_by_user(sk)) {
505 if (!(type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED))
506 __NET_INC_STATS(net, LINUX_MIB_LOCKDROPPEDICMPS);
507 }
508 if (sk->sk_state == TCP_CLOSE)
509 goto out;
510
511 if (unlikely(iph->ttl < inet_sk(sk)->min_ttl)) {
512 __NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP);
513 goto out;
514 }
515
516 tp = tcp_sk(sk);
517 /* XXX (TFO) - tp->snd_una should be ISN (tcp_create_openreq_child() */
518 fastopen = rcu_dereference(tp->fastopen_rsk);
519 snd_una = fastopen ? tcp_rsk(fastopen)->snt_isn : tp->snd_una;
520 if (sk->sk_state != TCP_LISTEN &&
521 !between(seq, snd_una, tp->snd_nxt)) {
522 __NET_INC_STATS(net, LINUX_MIB_OUTOFWINDOWICMPS);
523 goto out;
524 }
525
526 switch (type) {
527 case ICMP_REDIRECT:
528 if (!sock_owned_by_user(sk))
529 do_redirect(skb, sk);
530 goto out;
531 case ICMP_SOURCE_QUENCH:
532 /* Just silently ignore these. */
533 goto out;
534 case ICMP_PARAMETERPROB:
535 err = EPROTO;
536 break;
537 case ICMP_DEST_UNREACH:
538 if (code > NR_ICMP_UNREACH)
539 goto out;
540
541 if (code == ICMP_FRAG_NEEDED) { /* PMTU discovery (RFC1191) */
542 /* We are not interested in TCP_LISTEN and open_requests
543 * (SYN-ACKs send out by Linux are always <576bytes so
544 * they should go through unfragmented).
545 */
546 if (sk->sk_state == TCP_LISTEN)
547 goto out;
548
549 tp->mtu_info = info;
550 if (!sock_owned_by_user(sk)) {
551 tcp_v4_mtu_reduced(sk);
552 } else {
553 if (!test_and_set_bit(TCP_MTU_REDUCED_DEFERRED, &sk->sk_tsq_flags))
554 sock_hold(sk);
555 }
556 goto out;
557 }
558
559 err = icmp_err_convert[code].errno;
560 /* check if this ICMP message allows revert of backoff.
561 * (see RFC 6069)
562 */
563 if (!fastopen &&
564 (code == ICMP_NET_UNREACH || code == ICMP_HOST_UNREACH))
565 tcp_ld_RTO_revert(sk, seq);
566 break;
567 case ICMP_TIME_EXCEEDED:
568 err = EHOSTUNREACH;
569 break;
570 default:
571 goto out;
572 }
573
574 switch (sk->sk_state) {
575 case TCP_SYN_SENT:
576 case TCP_SYN_RECV:
577 /* Only in fast or simultaneous open. If a fast open socket is
578 * is already accepted it is treated as a connected one below.
579 */
580 if (fastopen && !fastopen->sk)
581 break;
582
583 ip_icmp_error(sk, skb, err, th->dest, info, (u8 *)th);
584
585 if (!sock_owned_by_user(sk)) {
586 sk->sk_err = err;
587
588 sk->sk_error_report(sk);
589
590 tcp_done(sk);
591 } else {
592 sk->sk_err_soft = err;
593 }
594 goto out;
595 }
596
597 /* If we've already connected we will keep trying
598 * until we time out, or the user gives up.
599 *
600 * rfc1122 4.2.3.9 allows to consider as hard errors
601 * only PROTO_UNREACH and PORT_UNREACH (well, FRAG_FAILED too,
602 * but it is obsoleted by pmtu discovery).
603 *
604 * Note, that in modern internet, where routing is unreliable
605 * and in each dark corner broken firewalls sit, sending random
606 * errors ordered by their masters even this two messages finally lose
607 * their original sense (even Linux sends invalid PORT_UNREACHs)
608 *
609 * Now we are in compliance with RFCs.
610 * --ANK (980905)
611 */
612
613 inet = inet_sk(sk);
614 if (!sock_owned_by_user(sk) && inet->recverr) {
615 sk->sk_err = err;
616 sk->sk_error_report(sk);
617 } else { /* Only an error on timeout */
618 sk->sk_err_soft = err;
619 }
620
621out:
622 bh_unlock_sock(sk);
623 sock_put(sk);
624 return 0;
625}
626
627void __tcp_v4_send_check(struct sk_buff *skb, __be32 saddr, __be32 daddr)
628{
629 struct tcphdr *th = tcp_hdr(skb);
630
631 th->check = ~tcp_v4_check(skb->len, saddr, daddr, 0);
632 skb->csum_start = skb_transport_header(skb) - skb->head;
633 skb->csum_offset = offsetof(struct tcphdr, check);
634}
635
636/* This routine computes an IPv4 TCP checksum. */
637void tcp_v4_send_check(struct sock *sk, struct sk_buff *skb)
638{
639 const struct inet_sock *inet = inet_sk(sk);
640
641 __tcp_v4_send_check(skb, inet->inet_saddr, inet->inet_daddr);
642}
643EXPORT_SYMBOL(tcp_v4_send_check);
644
645/*
646 * This routine will send an RST to the other tcp.
647 *
648 * Someone asks: why I NEVER use socket parameters (TOS, TTL etc.)
649 * for reset.
650 * Answer: if a packet caused RST, it is not for a socket
651 * existing in our system, if it is matched to a socket,
652 * it is just duplicate segment or bug in other side's TCP.
653 * So that we build reply only basing on parameters
654 * arrived with segment.
655 * Exception: precedence violation. We do not implement it in any case.
656 */
657
658static void tcp_v4_send_reset(const struct sock *sk, struct sk_buff *skb)
659{
660 const struct tcphdr *th = tcp_hdr(skb);
661 struct {
662 struct tcphdr th;
663#ifdef CONFIG_TCP_MD5SIG
664 __be32 opt[(TCPOLEN_MD5SIG_ALIGNED >> 2)];
665#endif
666 } rep;
667 struct ip_reply_arg arg;
668#ifdef CONFIG_TCP_MD5SIG
669 struct tcp_md5sig_key *key = NULL;
670 const __u8 *hash_location = NULL;
671 unsigned char newhash[16];
672 int genhash;
673 struct sock *sk1 = NULL;
674#endif
675 u64 transmit_time = 0;
676 struct sock *ctl_sk;
677 struct net *net;
678
679 /* Never send a reset in response to a reset. */
680 if (th->rst)
681 return;
682
683 /* If sk not NULL, it means we did a successful lookup and incoming
684 * route had to be correct. prequeue might have dropped our dst.
685 */
686 if (!sk && skb_rtable(skb)->rt_type != RTN_LOCAL)
687 return;
688
689 /* Swap the send and the receive. */
690 memset(&rep, 0, sizeof(rep));
691 rep.th.dest = th->source;
692 rep.th.source = th->dest;
693 rep.th.doff = sizeof(struct tcphdr) / 4;
694 rep.th.rst = 1;
695
696 if (th->ack) {
697 rep.th.seq = th->ack_seq;
698 } else {
699 rep.th.ack = 1;
700 rep.th.ack_seq = htonl(ntohl(th->seq) + th->syn + th->fin +
701 skb->len - (th->doff << 2));
702 }
703
704 memset(&arg, 0, sizeof(arg));
705 arg.iov[0].iov_base = (unsigned char *)&rep;
706 arg.iov[0].iov_len = sizeof(rep.th);
707
708 net = sk ? sock_net(sk) : dev_net(skb_dst(skb)->dev);
709#ifdef CONFIG_TCP_MD5SIG
710 rcu_read_lock();
711 hash_location = tcp_parse_md5sig_option(th);
712 if (sk && sk_fullsock(sk)) {
713 const union tcp_md5_addr *addr;
714 int l3index;
715
716 /* sdif set, means packet ingressed via a device
717 * in an L3 domain and inet_iif is set to it.
718 */
719 l3index = tcp_v4_sdif(skb) ? inet_iif(skb) : 0;
720 addr = (union tcp_md5_addr *)&ip_hdr(skb)->saddr;
721 key = tcp_md5_do_lookup(sk, l3index, addr, AF_INET);
722 } else if (hash_location) {
723 const union tcp_md5_addr *addr;
724 int sdif = tcp_v4_sdif(skb);
725 int dif = inet_iif(skb);
726 int l3index;
727
728 /*
729 * active side is lost. Try to find listening socket through
730 * source port, and then find md5 key through listening socket.
731 * we are not loose security here:
732 * Incoming packet is checked with md5 hash with finding key,
733 * no RST generated if md5 hash doesn't match.
734 */
735 sk1 = __inet_lookup_listener(net, &tcp_hashinfo, NULL, 0,
736 ip_hdr(skb)->saddr,
737 th->source, ip_hdr(skb)->daddr,
738 ntohs(th->source), dif, sdif);
739 /* don't send rst if it can't find key */
740 if (!sk1)
741 goto out;
742
743 /* sdif set, means packet ingressed via a device
744 * in an L3 domain and dif is set to it.
745 */
746 l3index = sdif ? dif : 0;
747 addr = (union tcp_md5_addr *)&ip_hdr(skb)->saddr;
748 key = tcp_md5_do_lookup(sk1, l3index, addr, AF_INET);
749 if (!key)
750 goto out;
751
752
753 genhash = tcp_v4_md5_hash_skb(newhash, key, NULL, skb);
754 if (genhash || memcmp(hash_location, newhash, 16) != 0)
755 goto out;
756
757 }
758
759 if (key) {
760 rep.opt[0] = htonl((TCPOPT_NOP << 24) |
761 (TCPOPT_NOP << 16) |
762 (TCPOPT_MD5SIG << 8) |
763 TCPOLEN_MD5SIG);
764 /* Update length and the length the header thinks exists */
765 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED;
766 rep.th.doff = arg.iov[0].iov_len / 4;
767
768 tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[1],
769 key, ip_hdr(skb)->saddr,
770 ip_hdr(skb)->daddr, &rep.th);
771 }
772#endif
773 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
774 ip_hdr(skb)->saddr, /* XXX */
775 arg.iov[0].iov_len, IPPROTO_TCP, 0);
776 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
777 arg.flags = (sk && inet_sk_transparent(sk)) ? IP_REPLY_ARG_NOSRCCHECK : 0;
778
779 /* When socket is gone, all binding information is lost.
780 * routing might fail in this case. No choice here, if we choose to force
781 * input interface, we will misroute in case of asymmetric route.
782 */
783 if (sk) {
784 arg.bound_dev_if = sk->sk_bound_dev_if;
785 if (sk_fullsock(sk))
786 trace_tcp_send_reset(sk, skb);
787 }
788
789 BUILD_BUG_ON(offsetof(struct sock, sk_bound_dev_if) !=
790 offsetof(struct inet_timewait_sock, tw_bound_dev_if));
791
792 arg.tos = ip_hdr(skb)->tos;
793 arg.uid = sock_net_uid(net, sk && sk_fullsock(sk) ? sk : NULL);
794 local_bh_disable();
795 ctl_sk = this_cpu_read(*net->ipv4.tcp_sk);
796 if (sk) {
797 ctl_sk->sk_mark = (sk->sk_state == TCP_TIME_WAIT) ?
798 inet_twsk(sk)->tw_mark : sk->sk_mark;
799 ctl_sk->sk_priority = (sk->sk_state == TCP_TIME_WAIT) ?
800 inet_twsk(sk)->tw_priority : sk->sk_priority;
801 transmit_time = tcp_transmit_time(sk);
802 }
803 ip_send_unicast_reply(ctl_sk,
804 skb, &TCP_SKB_CB(skb)->header.h4.opt,
805 ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
806 &arg, arg.iov[0].iov_len,
807 transmit_time);
808
809 ctl_sk->sk_mark = 0;
810 __TCP_INC_STATS(net, TCP_MIB_OUTSEGS);
811 __TCP_INC_STATS(net, TCP_MIB_OUTRSTS);
812 local_bh_enable();
813
814#ifdef CONFIG_TCP_MD5SIG
815out:
816 rcu_read_unlock();
817#endif
818}
819
820/* The code following below sending ACKs in SYN-RECV and TIME-WAIT states
821 outside socket context is ugly, certainly. What can I do?
822 */
823
824static void tcp_v4_send_ack(const struct sock *sk,
825 struct sk_buff *skb, u32 seq, u32 ack,
826 u32 win, u32 tsval, u32 tsecr, int oif,
827 struct tcp_md5sig_key *key,
828 int reply_flags, u8 tos)
829{
830 const struct tcphdr *th = tcp_hdr(skb);
831 struct {
832 struct tcphdr th;
833 __be32 opt[(TCPOLEN_TSTAMP_ALIGNED >> 2)
834#ifdef CONFIG_TCP_MD5SIG
835 + (TCPOLEN_MD5SIG_ALIGNED >> 2)
836#endif
837 ];
838 } rep;
839 struct net *net = sock_net(sk);
840 struct ip_reply_arg arg;
841 struct sock *ctl_sk;
842 u64 transmit_time;
843
844 memset(&rep.th, 0, sizeof(struct tcphdr));
845 memset(&arg, 0, sizeof(arg));
846
847 arg.iov[0].iov_base = (unsigned char *)&rep;
848 arg.iov[0].iov_len = sizeof(rep.th);
849 if (tsecr) {
850 rep.opt[0] = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
851 (TCPOPT_TIMESTAMP << 8) |
852 TCPOLEN_TIMESTAMP);
853 rep.opt[1] = htonl(tsval);
854 rep.opt[2] = htonl(tsecr);
855 arg.iov[0].iov_len += TCPOLEN_TSTAMP_ALIGNED;
856 }
857
858 /* Swap the send and the receive. */
859 rep.th.dest = th->source;
860 rep.th.source = th->dest;
861 rep.th.doff = arg.iov[0].iov_len / 4;
862 rep.th.seq = htonl(seq);
863 rep.th.ack_seq = htonl(ack);
864 rep.th.ack = 1;
865 rep.th.window = htons(win);
866
867#ifdef CONFIG_TCP_MD5SIG
868 if (key) {
869 int offset = (tsecr) ? 3 : 0;
870
871 rep.opt[offset++] = htonl((TCPOPT_NOP << 24) |
872 (TCPOPT_NOP << 16) |
873 (TCPOPT_MD5SIG << 8) |
874 TCPOLEN_MD5SIG);
875 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED;
876 rep.th.doff = arg.iov[0].iov_len/4;
877
878 tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[offset],
879 key, ip_hdr(skb)->saddr,
880 ip_hdr(skb)->daddr, &rep.th);
881 }
882#endif
883 arg.flags = reply_flags;
884 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
885 ip_hdr(skb)->saddr, /* XXX */
886 arg.iov[0].iov_len, IPPROTO_TCP, 0);
887 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
888 if (oif)
889 arg.bound_dev_if = oif;
890 arg.tos = tos;
891 arg.uid = sock_net_uid(net, sk_fullsock(sk) ? sk : NULL);
892 local_bh_disable();
893 ctl_sk = this_cpu_read(*net->ipv4.tcp_sk);
894 ctl_sk->sk_mark = (sk->sk_state == TCP_TIME_WAIT) ?
895 inet_twsk(sk)->tw_mark : sk->sk_mark;
896 ctl_sk->sk_priority = (sk->sk_state == TCP_TIME_WAIT) ?
897 inet_twsk(sk)->tw_priority : sk->sk_priority;
898 transmit_time = tcp_transmit_time(sk);
899 ip_send_unicast_reply(ctl_sk,
900 skb, &TCP_SKB_CB(skb)->header.h4.opt,
901 ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
902 &arg, arg.iov[0].iov_len,
903 transmit_time);
904
905 ctl_sk->sk_mark = 0;
906 __TCP_INC_STATS(net, TCP_MIB_OUTSEGS);
907 local_bh_enable();
908}
909
910static void tcp_v4_timewait_ack(struct sock *sk, struct sk_buff *skb)
911{
912 struct inet_timewait_sock *tw = inet_twsk(sk);
913 struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
914
915 tcp_v4_send_ack(sk, skb,
916 tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
917 tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
918 tcp_time_stamp_raw() + tcptw->tw_ts_offset,
919 tcptw->tw_ts_recent,
920 tw->tw_bound_dev_if,
921 tcp_twsk_md5_key(tcptw),
922 tw->tw_transparent ? IP_REPLY_ARG_NOSRCCHECK : 0,
923 tw->tw_tos
924 );
925
926 inet_twsk_put(tw);
927}
928
929static void tcp_v4_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb,
930 struct request_sock *req)
931{
932 const union tcp_md5_addr *addr;
933 int l3index;
934
935 /* sk->sk_state == TCP_LISTEN -> for regular TCP_SYN_RECV
936 * sk->sk_state == TCP_SYN_RECV -> for Fast Open.
937 */
938 u32 seq = (sk->sk_state == TCP_LISTEN) ? tcp_rsk(req)->snt_isn + 1 :
939 tcp_sk(sk)->snd_nxt;
940
941 /* RFC 7323 2.3
942 * The window field (SEG.WND) of every outgoing segment, with the
943 * exception of <SYN> segments, MUST be right-shifted by
944 * Rcv.Wind.Shift bits:
945 */
946 addr = (union tcp_md5_addr *)&ip_hdr(skb)->saddr;
947 l3index = tcp_v4_sdif(skb) ? inet_iif(skb) : 0;
948 tcp_v4_send_ack(sk, skb, seq,
949 tcp_rsk(req)->rcv_nxt,
950 req->rsk_rcv_wnd >> inet_rsk(req)->rcv_wscale,
951 tcp_time_stamp_raw() + tcp_rsk(req)->ts_off,
952 req->ts_recent,
953 0,
954 tcp_md5_do_lookup(sk, l3index, addr, AF_INET),
955 inet_rsk(req)->no_srccheck ? IP_REPLY_ARG_NOSRCCHECK : 0,
956 ip_hdr(skb)->tos);
957}
958
959/*
960 * Send a SYN-ACK after having received a SYN.
961 * This still operates on a request_sock only, not on a big
962 * socket.
963 */
964static int tcp_v4_send_synack(const struct sock *sk, struct dst_entry *dst,
965 struct flowi *fl,
966 struct request_sock *req,
967 struct tcp_fastopen_cookie *foc,
968 enum tcp_synack_type synack_type)
969{
970 const struct inet_request_sock *ireq = inet_rsk(req);
971 struct flowi4 fl4;
972 int err = -1;
973 struct sk_buff *skb;
974
975 /* First, grab a route. */
976 if (!dst && (dst = inet_csk_route_req(sk, &fl4, req)) == NULL)
977 return -1;
978
979 skb = tcp_make_synack(sk, dst, req, foc, synack_type);
980
981 if (skb) {
982 __tcp_v4_send_check(skb, ireq->ir_loc_addr, ireq->ir_rmt_addr);
983
984 rcu_read_lock();
985 err = ip_build_and_send_pkt(skb, sk, ireq->ir_loc_addr,
986 ireq->ir_rmt_addr,
987 rcu_dereference(ireq->ireq_opt));
988 rcu_read_unlock();
989 err = net_xmit_eval(err);
990 }
991
992 return err;
993}
994
995/*
996 * IPv4 request_sock destructor.
997 */
998static void tcp_v4_reqsk_destructor(struct request_sock *req)
999{
1000 kfree(rcu_dereference_protected(inet_rsk(req)->ireq_opt, 1));
1001}
1002
1003#ifdef CONFIG_TCP_MD5SIG
1004/*
1005 * RFC2385 MD5 checksumming requires a mapping of
1006 * IP address->MD5 Key.
1007 * We need to maintain these in the sk structure.
1008 */
1009
1010DEFINE_STATIC_KEY_FALSE(tcp_md5_needed);
1011EXPORT_SYMBOL(tcp_md5_needed);
1012
1013/* Find the Key structure for an address. */
1014struct tcp_md5sig_key *__tcp_md5_do_lookup(const struct sock *sk, int l3index,
1015 const union tcp_md5_addr *addr,
1016 int family)
1017{
1018 const struct tcp_sock *tp = tcp_sk(sk);
1019 struct tcp_md5sig_key *key;
1020 const struct tcp_md5sig_info *md5sig;
1021 __be32 mask;
1022 struct tcp_md5sig_key *best_match = NULL;
1023 bool match;
1024
1025 /* caller either holds rcu_read_lock() or socket lock */
1026 md5sig = rcu_dereference_check(tp->md5sig_info,
1027 lockdep_sock_is_held(sk));
1028 if (!md5sig)
1029 return NULL;
1030
1031 hlist_for_each_entry_rcu(key, &md5sig->head, node,
1032 lockdep_sock_is_held(sk)) {
1033 if (key->family != family)
1034 continue;
1035 if (key->l3index && key->l3index != l3index)
1036 continue;
1037 if (family == AF_INET) {
1038 mask = inet_make_mask(key->prefixlen);
1039 match = (key->addr.a4.s_addr & mask) ==
1040 (addr->a4.s_addr & mask);
1041#if IS_ENABLED(CONFIG_IPV6)
1042 } else if (family == AF_INET6) {
1043 match = ipv6_prefix_equal(&key->addr.a6, &addr->a6,
1044 key->prefixlen);
1045#endif
1046 } else {
1047 match = false;
1048 }
1049
1050 if (match && (!best_match ||
1051 key->prefixlen > best_match->prefixlen))
1052 best_match = key;
1053 }
1054 return best_match;
1055}
1056EXPORT_SYMBOL(__tcp_md5_do_lookup);
1057
1058static struct tcp_md5sig_key *tcp_md5_do_lookup_exact(const struct sock *sk,
1059 const union tcp_md5_addr *addr,
1060 int family, u8 prefixlen,
1061 int l3index)
1062{
1063 const struct tcp_sock *tp = tcp_sk(sk);
1064 struct tcp_md5sig_key *key;
1065 unsigned int size = sizeof(struct in_addr);
1066 const struct tcp_md5sig_info *md5sig;
1067
1068 /* caller either holds rcu_read_lock() or socket lock */
1069 md5sig = rcu_dereference_check(tp->md5sig_info,
1070 lockdep_sock_is_held(sk));
1071 if (!md5sig)
1072 return NULL;
1073#if IS_ENABLED(CONFIG_IPV6)
1074 if (family == AF_INET6)
1075 size = sizeof(struct in6_addr);
1076#endif
1077 hlist_for_each_entry_rcu(key, &md5sig->head, node,
1078 lockdep_sock_is_held(sk)) {
1079 if (key->family != family)
1080 continue;
1081 if (key->l3index && key->l3index != l3index)
1082 continue;
1083 if (!memcmp(&key->addr, addr, size) &&
1084 key->prefixlen == prefixlen)
1085 return key;
1086 }
1087 return NULL;
1088}
1089
1090struct tcp_md5sig_key *tcp_v4_md5_lookup(const struct sock *sk,
1091 const struct sock *addr_sk)
1092{
1093 const union tcp_md5_addr *addr;
1094 int l3index;
1095
1096 l3index = l3mdev_master_ifindex_by_index(sock_net(sk),
1097 addr_sk->sk_bound_dev_if);
1098 addr = (const union tcp_md5_addr *)&addr_sk->sk_daddr;
1099 return tcp_md5_do_lookup(sk, l3index, addr, AF_INET);
1100}
1101EXPORT_SYMBOL(tcp_v4_md5_lookup);
1102
1103/* This can be called on a newly created socket, from other files */
1104int tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr,
1105 int family, u8 prefixlen, int l3index,
1106 const u8 *newkey, u8 newkeylen, gfp_t gfp)
1107{
1108 /* Add Key to the list */
1109 struct tcp_md5sig_key *key;
1110 struct tcp_sock *tp = tcp_sk(sk);
1111 struct tcp_md5sig_info *md5sig;
1112
1113 key = tcp_md5_do_lookup_exact(sk, addr, family, prefixlen, l3index);
1114 if (key) {
1115 /* Pre-existing entry - just update that one.
1116 * Note that the key might be used concurrently.
1117 * data_race() is telling kcsan that we do not care of
1118 * key mismatches, since changing MD5 key on live flows
1119 * can lead to packet drops.
1120 */
1121 data_race(memcpy(key->key, newkey, newkeylen));
1122
1123 /* Pairs with READ_ONCE() in tcp_md5_hash_key().
1124 * Also note that a reader could catch new key->keylen value
1125 * but old key->key[], this is the reason we use __GFP_ZERO
1126 * at sock_kmalloc() time below these lines.
1127 */
1128 WRITE_ONCE(key->keylen, newkeylen);
1129
1130 return 0;
1131 }
1132
1133 md5sig = rcu_dereference_protected(tp->md5sig_info,
1134 lockdep_sock_is_held(sk));
1135 if (!md5sig) {
1136 md5sig = kmalloc(sizeof(*md5sig), gfp);
1137 if (!md5sig)
1138 return -ENOMEM;
1139
1140 sk_nocaps_add(sk, NETIF_F_GSO_MASK);
1141 INIT_HLIST_HEAD(&md5sig->head);
1142 rcu_assign_pointer(tp->md5sig_info, md5sig);
1143 }
1144
1145 key = sock_kmalloc(sk, sizeof(*key), gfp | __GFP_ZERO);
1146 if (!key)
1147 return -ENOMEM;
1148 if (!tcp_alloc_md5sig_pool()) {
1149 sock_kfree_s(sk, key, sizeof(*key));
1150 return -ENOMEM;
1151 }
1152
1153 memcpy(key->key, newkey, newkeylen);
1154 key->keylen = newkeylen;
1155 key->family = family;
1156 key->prefixlen = prefixlen;
1157 key->l3index = l3index;
1158 memcpy(&key->addr, addr,
1159 (family == AF_INET6) ? sizeof(struct in6_addr) :
1160 sizeof(struct in_addr));
1161 hlist_add_head_rcu(&key->node, &md5sig->head);
1162 return 0;
1163}
1164EXPORT_SYMBOL(tcp_md5_do_add);
1165
1166int tcp_md5_do_del(struct sock *sk, const union tcp_md5_addr *addr, int family,
1167 u8 prefixlen, int l3index)
1168{
1169 struct tcp_md5sig_key *key;
1170
1171 key = tcp_md5_do_lookup_exact(sk, addr, family, prefixlen, l3index);
1172 if (!key)
1173 return -ENOENT;
1174 hlist_del_rcu(&key->node);
1175 atomic_sub(sizeof(*key), &sk->sk_omem_alloc);
1176 kfree_rcu(key, rcu);
1177 return 0;
1178}
1179EXPORT_SYMBOL(tcp_md5_do_del);
1180
1181static void tcp_clear_md5_list(struct sock *sk)
1182{
1183 struct tcp_sock *tp = tcp_sk(sk);
1184 struct tcp_md5sig_key *key;
1185 struct hlist_node *n;
1186 struct tcp_md5sig_info *md5sig;
1187
1188 md5sig = rcu_dereference_protected(tp->md5sig_info, 1);
1189
1190 hlist_for_each_entry_safe(key, n, &md5sig->head, node) {
1191 hlist_del_rcu(&key->node);
1192 atomic_sub(sizeof(*key), &sk->sk_omem_alloc);
1193 kfree_rcu(key, rcu);
1194 }
1195}
1196
1197static int tcp_v4_parse_md5_keys(struct sock *sk, int optname,
1198 sockptr_t optval, int optlen)
1199{
1200 struct tcp_md5sig cmd;
1201 struct sockaddr_in *sin = (struct sockaddr_in *)&cmd.tcpm_addr;
1202 const union tcp_md5_addr *addr;
1203 u8 prefixlen = 32;
1204 int l3index = 0;
1205
1206 if (optlen < sizeof(cmd))
1207 return -EINVAL;
1208
1209 if (copy_from_sockptr(&cmd, optval, sizeof(cmd)))
1210 return -EFAULT;
1211
1212 if (sin->sin_family != AF_INET)
1213 return -EINVAL;
1214
1215 if (optname == TCP_MD5SIG_EXT &&
1216 cmd.tcpm_flags & TCP_MD5SIG_FLAG_PREFIX) {
1217 prefixlen = cmd.tcpm_prefixlen;
1218 if (prefixlen > 32)
1219 return -EINVAL;
1220 }
1221
1222 if (optname == TCP_MD5SIG_EXT &&
1223 cmd.tcpm_flags & TCP_MD5SIG_FLAG_IFINDEX) {
1224 struct net_device *dev;
1225
1226 rcu_read_lock();
1227 dev = dev_get_by_index_rcu(sock_net(sk), cmd.tcpm_ifindex);
1228 if (dev && netif_is_l3_master(dev))
1229 l3index = dev->ifindex;
1230
1231 rcu_read_unlock();
1232
1233 /* ok to reference set/not set outside of rcu;
1234 * right now device MUST be an L3 master
1235 */
1236 if (!dev || !l3index)
1237 return -EINVAL;
1238 }
1239
1240 addr = (union tcp_md5_addr *)&sin->sin_addr.s_addr;
1241
1242 if (!cmd.tcpm_keylen)
1243 return tcp_md5_do_del(sk, addr, AF_INET, prefixlen, l3index);
1244
1245 if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN)
1246 return -EINVAL;
1247
1248 return tcp_md5_do_add(sk, addr, AF_INET, prefixlen, l3index,
1249 cmd.tcpm_key, cmd.tcpm_keylen, GFP_KERNEL);
1250}
1251
1252static int tcp_v4_md5_hash_headers(struct tcp_md5sig_pool *hp,
1253 __be32 daddr, __be32 saddr,
1254 const struct tcphdr *th, int nbytes)
1255{
1256 struct tcp4_pseudohdr *bp;
1257 struct scatterlist sg;
1258 struct tcphdr *_th;
1259
1260 bp = hp->scratch;
1261 bp->saddr = saddr;
1262 bp->daddr = daddr;
1263 bp->pad = 0;
1264 bp->protocol = IPPROTO_TCP;
1265 bp->len = cpu_to_be16(nbytes);
1266
1267 _th = (struct tcphdr *)(bp + 1);
1268 memcpy(_th, th, sizeof(*th));
1269 _th->check = 0;
1270
1271 sg_init_one(&sg, bp, sizeof(*bp) + sizeof(*th));
1272 ahash_request_set_crypt(hp->md5_req, &sg, NULL,
1273 sizeof(*bp) + sizeof(*th));
1274 return crypto_ahash_update(hp->md5_req);
1275}
1276
1277static int tcp_v4_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key,
1278 __be32 daddr, __be32 saddr, const struct tcphdr *th)
1279{
1280 struct tcp_md5sig_pool *hp;
1281 struct ahash_request *req;
1282
1283 hp = tcp_get_md5sig_pool();
1284 if (!hp)
1285 goto clear_hash_noput;
1286 req = hp->md5_req;
1287
1288 if (crypto_ahash_init(req))
1289 goto clear_hash;
1290 if (tcp_v4_md5_hash_headers(hp, daddr, saddr, th, th->doff << 2))
1291 goto clear_hash;
1292 if (tcp_md5_hash_key(hp, key))
1293 goto clear_hash;
1294 ahash_request_set_crypt(req, NULL, md5_hash, 0);
1295 if (crypto_ahash_final(req))
1296 goto clear_hash;
1297
1298 tcp_put_md5sig_pool();
1299 return 0;
1300
1301clear_hash:
1302 tcp_put_md5sig_pool();
1303clear_hash_noput:
1304 memset(md5_hash, 0, 16);
1305 return 1;
1306}
1307
1308int tcp_v4_md5_hash_skb(char *md5_hash, const struct tcp_md5sig_key *key,
1309 const struct sock *sk,
1310 const struct sk_buff *skb)
1311{
1312 struct tcp_md5sig_pool *hp;
1313 struct ahash_request *req;
1314 const struct tcphdr *th = tcp_hdr(skb);
1315 __be32 saddr, daddr;
1316
1317 if (sk) { /* valid for establish/request sockets */
1318 saddr = sk->sk_rcv_saddr;
1319 daddr = sk->sk_daddr;
1320 } else {
1321 const struct iphdr *iph = ip_hdr(skb);
1322 saddr = iph->saddr;
1323 daddr = iph->daddr;
1324 }
1325
1326 hp = tcp_get_md5sig_pool();
1327 if (!hp)
1328 goto clear_hash_noput;
1329 req = hp->md5_req;
1330
1331 if (crypto_ahash_init(req))
1332 goto clear_hash;
1333
1334 if (tcp_v4_md5_hash_headers(hp, daddr, saddr, th, skb->len))
1335 goto clear_hash;
1336 if (tcp_md5_hash_skb_data(hp, skb, th->doff << 2))
1337 goto clear_hash;
1338 if (tcp_md5_hash_key(hp, key))
1339 goto clear_hash;
1340 ahash_request_set_crypt(req, NULL, md5_hash, 0);
1341 if (crypto_ahash_final(req))
1342 goto clear_hash;
1343
1344 tcp_put_md5sig_pool();
1345 return 0;
1346
1347clear_hash:
1348 tcp_put_md5sig_pool();
1349clear_hash_noput:
1350 memset(md5_hash, 0, 16);
1351 return 1;
1352}
1353EXPORT_SYMBOL(tcp_v4_md5_hash_skb);
1354
1355#endif
1356
1357/* Called with rcu_read_lock() */
1358static bool tcp_v4_inbound_md5_hash(const struct sock *sk,
1359 const struct sk_buff *skb,
1360 int dif, int sdif)
1361{
1362#ifdef CONFIG_TCP_MD5SIG
1363 /*
1364 * This gets called for each TCP segment that arrives
1365 * so we want to be efficient.
1366 * We have 3 drop cases:
1367 * o No MD5 hash and one expected.
1368 * o MD5 hash and we're not expecting one.
1369 * o MD5 hash and its wrong.
1370 */
1371 const __u8 *hash_location = NULL;
1372 struct tcp_md5sig_key *hash_expected;
1373 const struct iphdr *iph = ip_hdr(skb);
1374 const struct tcphdr *th = tcp_hdr(skb);
1375 const union tcp_md5_addr *addr;
1376 unsigned char newhash[16];
1377 int genhash, l3index;
1378
1379 /* sdif set, means packet ingressed via a device
1380 * in an L3 domain and dif is set to the l3mdev
1381 */
1382 l3index = sdif ? dif : 0;
1383
1384 addr = (union tcp_md5_addr *)&iph->saddr;
1385 hash_expected = tcp_md5_do_lookup(sk, l3index, addr, AF_INET);
1386 hash_location = tcp_parse_md5sig_option(th);
1387
1388 /* We've parsed the options - do we have a hash? */
1389 if (!hash_expected && !hash_location)
1390 return false;
1391
1392 if (hash_expected && !hash_location) {
1393 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5NOTFOUND);
1394 return true;
1395 }
1396
1397 if (!hash_expected && hash_location) {
1398 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5UNEXPECTED);
1399 return true;
1400 }
1401
1402 /* Okay, so this is hash_expected and hash_location -
1403 * so we need to calculate the checksum.
1404 */
1405 genhash = tcp_v4_md5_hash_skb(newhash,
1406 hash_expected,
1407 NULL, skb);
1408
1409 if (genhash || memcmp(hash_location, newhash, 16) != 0) {
1410 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5FAILURE);
1411 net_info_ratelimited("MD5 Hash failed for (%pI4, %d)->(%pI4, %d)%s L3 index %d\n",
1412 &iph->saddr, ntohs(th->source),
1413 &iph->daddr, ntohs(th->dest),
1414 genhash ? " tcp_v4_calc_md5_hash failed"
1415 : "", l3index);
1416 return true;
1417 }
1418 return false;
1419#endif
1420 return false;
1421}
1422
1423static void tcp_v4_init_req(struct request_sock *req,
1424 const struct sock *sk_listener,
1425 struct sk_buff *skb)
1426{
1427 struct inet_request_sock *ireq = inet_rsk(req);
1428 struct net *net = sock_net(sk_listener);
1429
1430 sk_rcv_saddr_set(req_to_sk(req), ip_hdr(skb)->daddr);
1431 sk_daddr_set(req_to_sk(req), ip_hdr(skb)->saddr);
1432 RCU_INIT_POINTER(ireq->ireq_opt, tcp_v4_save_options(net, skb));
1433}
1434
1435static struct dst_entry *tcp_v4_route_req(const struct sock *sk,
1436 struct flowi *fl,
1437 const struct request_sock *req)
1438{
1439 return inet_csk_route_req(sk, &fl->u.ip4, req);
1440}
1441
1442struct request_sock_ops tcp_request_sock_ops __read_mostly = {
1443 .family = PF_INET,
1444 .obj_size = sizeof(struct tcp_request_sock),
1445 .rtx_syn_ack = tcp_rtx_synack,
1446 .send_ack = tcp_v4_reqsk_send_ack,
1447 .destructor = tcp_v4_reqsk_destructor,
1448 .send_reset = tcp_v4_send_reset,
1449 .syn_ack_timeout = tcp_syn_ack_timeout,
1450};
1451
1452const struct tcp_request_sock_ops tcp_request_sock_ipv4_ops = {
1453 .mss_clamp = TCP_MSS_DEFAULT,
1454#ifdef CONFIG_TCP_MD5SIG
1455 .req_md5_lookup = tcp_v4_md5_lookup,
1456 .calc_md5_hash = tcp_v4_md5_hash_skb,
1457#endif
1458 .init_req = tcp_v4_init_req,
1459#ifdef CONFIG_SYN_COOKIES
1460 .cookie_init_seq = cookie_v4_init_sequence,
1461#endif
1462 .route_req = tcp_v4_route_req,
1463 .init_seq = tcp_v4_init_seq,
1464 .init_ts_off = tcp_v4_init_ts_off,
1465 .send_synack = tcp_v4_send_synack,
1466};
1467
1468int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
1469{
1470 /* Never answer to SYNs send to broadcast or multicast */
1471 if (skb_rtable(skb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
1472 goto drop;
1473
1474 return tcp_conn_request(&tcp_request_sock_ops,
1475 &tcp_request_sock_ipv4_ops, sk, skb);
1476
1477drop:
1478 tcp_listendrop(sk);
1479 return 0;
1480}
1481EXPORT_SYMBOL(tcp_v4_conn_request);
1482
1483
1484/*
1485 * The three way handshake has completed - we got a valid synack -
1486 * now create the new socket.
1487 */
1488struct sock *tcp_v4_syn_recv_sock(const struct sock *sk, struct sk_buff *skb,
1489 struct request_sock *req,
1490 struct dst_entry *dst,
1491 struct request_sock *req_unhash,
1492 bool *own_req)
1493{
1494 struct inet_request_sock *ireq;
1495 struct inet_sock *newinet;
1496 struct tcp_sock *newtp;
1497 struct sock *newsk;
1498#ifdef CONFIG_TCP_MD5SIG
1499 const union tcp_md5_addr *addr;
1500 struct tcp_md5sig_key *key;
1501 int l3index;
1502#endif
1503 struct ip_options_rcu *inet_opt;
1504
1505 if (sk_acceptq_is_full(sk))
1506 goto exit_overflow;
1507
1508 newsk = tcp_create_openreq_child(sk, req, skb);
1509 if (!newsk)
1510 goto exit_nonewsk;
1511
1512 newsk->sk_gso_type = SKB_GSO_TCPV4;
1513 inet_sk_rx_dst_set(newsk, skb);
1514
1515 newtp = tcp_sk(newsk);
1516 newinet = inet_sk(newsk);
1517 ireq = inet_rsk(req);
1518 sk_daddr_set(newsk, ireq->ir_rmt_addr);
1519 sk_rcv_saddr_set(newsk, ireq->ir_loc_addr);
1520 newsk->sk_bound_dev_if = ireq->ir_iif;
1521 newinet->inet_saddr = ireq->ir_loc_addr;
1522 inet_opt = rcu_dereference(ireq->ireq_opt);
1523 RCU_INIT_POINTER(newinet->inet_opt, inet_opt);
1524 newinet->mc_index = inet_iif(skb);
1525 newinet->mc_ttl = ip_hdr(skb)->ttl;
1526 newinet->rcv_tos = ip_hdr(skb)->tos;
1527 inet_csk(newsk)->icsk_ext_hdr_len = 0;
1528 if (inet_opt)
1529 inet_csk(newsk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
1530 newinet->inet_id = prandom_u32();
1531
1532 if (!dst) {
1533 dst = inet_csk_route_child_sock(sk, newsk, req);
1534 if (!dst)
1535 goto put_and_exit;
1536 } else {
1537 /* syncookie case : see end of cookie_v4_check() */
1538 }
1539 sk_setup_caps(newsk, dst);
1540
1541 tcp_ca_openreq_child(newsk, dst);
1542
1543 tcp_sync_mss(newsk, dst_mtu(dst));
1544 newtp->advmss = tcp_mss_clamp(tcp_sk(sk), dst_metric_advmss(dst));
1545
1546 tcp_initialize_rcv_mss(newsk);
1547
1548#ifdef CONFIG_TCP_MD5SIG
1549 l3index = l3mdev_master_ifindex_by_index(sock_net(sk), ireq->ir_iif);
1550 /* Copy over the MD5 key from the original socket */
1551 addr = (union tcp_md5_addr *)&newinet->inet_daddr;
1552 key = tcp_md5_do_lookup(sk, l3index, addr, AF_INET);
1553 if (key) {
1554 /*
1555 * We're using one, so create a matching key
1556 * on the newsk structure. If we fail to get
1557 * memory, then we end up not copying the key
1558 * across. Shucks.
1559 */
1560 tcp_md5_do_add(newsk, addr, AF_INET, 32, l3index,
1561 key->key, key->keylen, GFP_ATOMIC);
1562 sk_nocaps_add(newsk, NETIF_F_GSO_MASK);
1563 }
1564#endif
1565
1566 if (__inet_inherit_port(sk, newsk) < 0)
1567 goto put_and_exit;
1568 *own_req = inet_ehash_nolisten(newsk, req_to_sk(req_unhash));
1569 if (likely(*own_req)) {
1570 tcp_move_syn(newtp, req);
1571 ireq->ireq_opt = NULL;
1572 } else {
1573 newinet->inet_opt = NULL;
1574 }
1575 return newsk;
1576
1577exit_overflow:
1578 NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
1579exit_nonewsk:
1580 dst_release(dst);
1581exit:
1582 tcp_listendrop(sk);
1583 return NULL;
1584put_and_exit:
1585 newinet->inet_opt = NULL;
1586 inet_csk_prepare_forced_close(newsk);
1587 tcp_done(newsk);
1588 goto exit;
1589}
1590EXPORT_SYMBOL(tcp_v4_syn_recv_sock);
1591
1592static struct sock *tcp_v4_cookie_check(struct sock *sk, struct sk_buff *skb)
1593{
1594#ifdef CONFIG_SYN_COOKIES
1595 const struct tcphdr *th = tcp_hdr(skb);
1596
1597 if (!th->syn)
1598 sk = cookie_v4_check(sk, skb);
1599#endif
1600 return sk;
1601}
1602
1603u16 tcp_v4_get_syncookie(struct sock *sk, struct iphdr *iph,
1604 struct tcphdr *th, u32 *cookie)
1605{
1606 u16 mss = 0;
1607#ifdef CONFIG_SYN_COOKIES
1608 mss = tcp_get_syncookie_mss(&tcp_request_sock_ops,
1609 &tcp_request_sock_ipv4_ops, sk, th);
1610 if (mss) {
1611 *cookie = __cookie_v4_init_sequence(iph, th, &mss);
1612 tcp_synq_overflow(sk);
1613 }
1614#endif
1615 return mss;
1616}
1617
1618/* The socket must have it's spinlock held when we get
1619 * here, unless it is a TCP_LISTEN socket.
1620 *
1621 * We have a potential double-lock case here, so even when
1622 * doing backlog processing we use the BH locking scheme.
1623 * This is because we cannot sleep with the original spinlock
1624 * held.
1625 */
1626int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
1627{
1628 struct sock *rsk;
1629
1630 if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
1631 struct dst_entry *dst = sk->sk_rx_dst;
1632
1633 sock_rps_save_rxhash(sk, skb);
1634 sk_mark_napi_id(sk, skb);
1635 if (dst) {
1636 if (inet_sk(sk)->rx_dst_ifindex != skb->skb_iif ||
1637 !dst->ops->check(dst, 0)) {
1638 dst_release(dst);
1639 sk->sk_rx_dst = NULL;
1640 }
1641 }
1642 tcp_rcv_established(sk, skb);
1643 return 0;
1644 }
1645
1646 if (tcp_checksum_complete(skb))
1647 goto csum_err;
1648
1649 if (sk->sk_state == TCP_LISTEN) {
1650 struct sock *nsk = tcp_v4_cookie_check(sk, skb);
1651
1652 if (!nsk)
1653 goto discard;
1654 if (nsk != sk) {
1655 if (tcp_child_process(sk, nsk, skb)) {
1656 rsk = nsk;
1657 goto reset;
1658 }
1659 return 0;
1660 }
1661 } else
1662 sock_rps_save_rxhash(sk, skb);
1663
1664 if (tcp_rcv_state_process(sk, skb)) {
1665 rsk = sk;
1666 goto reset;
1667 }
1668 return 0;
1669
1670reset:
1671 tcp_v4_send_reset(rsk, skb);
1672discard:
1673 kfree_skb(skb);
1674 /* Be careful here. If this function gets more complicated and
1675 * gcc suffers from register pressure on the x86, sk (in %ebx)
1676 * might be destroyed here. This current version compiles correctly,
1677 * but you have been warned.
1678 */
1679 return 0;
1680
1681csum_err:
1682 TCP_INC_STATS(sock_net(sk), TCP_MIB_CSUMERRORS);
1683 TCP_INC_STATS(sock_net(sk), TCP_MIB_INERRS);
1684 goto discard;
1685}
1686EXPORT_SYMBOL(tcp_v4_do_rcv);
1687
1688int tcp_v4_early_demux(struct sk_buff *skb)
1689{
1690 const struct iphdr *iph;
1691 const struct tcphdr *th;
1692 struct sock *sk;
1693
1694 if (skb->pkt_type != PACKET_HOST)
1695 return 0;
1696
1697 if (!pskb_may_pull(skb, skb_transport_offset(skb) + sizeof(struct tcphdr)))
1698 return 0;
1699
1700 iph = ip_hdr(skb);
1701 th = tcp_hdr(skb);
1702
1703 if (th->doff < sizeof(struct tcphdr) / 4)
1704 return 0;
1705
1706 sk = __inet_lookup_established(dev_net(skb->dev), &tcp_hashinfo,
1707 iph->saddr, th->source,
1708 iph->daddr, ntohs(th->dest),
1709 skb->skb_iif, inet_sdif(skb));
1710 if (sk) {
1711 skb->sk = sk;
1712 skb->destructor = sock_edemux;
1713 if (sk_fullsock(sk)) {
1714 struct dst_entry *dst = READ_ONCE(sk->sk_rx_dst);
1715
1716 if (dst)
1717 dst = dst_check(dst, 0);
1718 if (dst &&
1719 inet_sk(sk)->rx_dst_ifindex == skb->skb_iif)
1720 skb_dst_set_noref(skb, dst);
1721 }
1722 }
1723 return 0;
1724}
1725
1726bool tcp_add_backlog(struct sock *sk, struct sk_buff *skb)
1727{
1728 u32 limit = READ_ONCE(sk->sk_rcvbuf) + READ_ONCE(sk->sk_sndbuf);
1729 struct skb_shared_info *shinfo;
1730 const struct tcphdr *th;
1731 struct tcphdr *thtail;
1732 struct sk_buff *tail;
1733 unsigned int hdrlen;
1734 bool fragstolen;
1735 u32 gso_segs;
1736 int delta;
1737
1738 /* In case all data was pulled from skb frags (in __pskb_pull_tail()),
1739 * we can fix skb->truesize to its real value to avoid future drops.
1740 * This is valid because skb is not yet charged to the socket.
1741 * It has been noticed pure SACK packets were sometimes dropped
1742 * (if cooked by drivers without copybreak feature).
1743 */
1744 skb_condense(skb);
1745
1746 skb_dst_drop(skb);
1747
1748 if (unlikely(tcp_checksum_complete(skb))) {
1749 bh_unlock_sock(sk);
1750 __TCP_INC_STATS(sock_net(sk), TCP_MIB_CSUMERRORS);
1751 __TCP_INC_STATS(sock_net(sk), TCP_MIB_INERRS);
1752 return true;
1753 }
1754
1755 /* Attempt coalescing to last skb in backlog, even if we are
1756 * above the limits.
1757 * This is okay because skb capacity is limited to MAX_SKB_FRAGS.
1758 */
1759 th = (const struct tcphdr *)skb->data;
1760 hdrlen = th->doff * 4;
1761 shinfo = skb_shinfo(skb);
1762
1763 if (!shinfo->gso_size)
1764 shinfo->gso_size = skb->len - hdrlen;
1765
1766 if (!shinfo->gso_segs)
1767 shinfo->gso_segs = 1;
1768
1769 tail = sk->sk_backlog.tail;
1770 if (!tail)
1771 goto no_coalesce;
1772 thtail = (struct tcphdr *)tail->data;
1773
1774 if (TCP_SKB_CB(tail)->end_seq != TCP_SKB_CB(skb)->seq ||
1775 TCP_SKB_CB(tail)->ip_dsfield != TCP_SKB_CB(skb)->ip_dsfield ||
1776 ((TCP_SKB_CB(tail)->tcp_flags |
1777 TCP_SKB_CB(skb)->tcp_flags) & (TCPHDR_SYN | TCPHDR_RST | TCPHDR_URG)) ||
1778 !((TCP_SKB_CB(tail)->tcp_flags &
1779 TCP_SKB_CB(skb)->tcp_flags) & TCPHDR_ACK) ||
1780 ((TCP_SKB_CB(tail)->tcp_flags ^
1781 TCP_SKB_CB(skb)->tcp_flags) & (TCPHDR_ECE | TCPHDR_CWR)) ||
1782#ifdef CONFIG_TLS_DEVICE
1783 tail->decrypted != skb->decrypted ||
1784#endif
1785 thtail->doff != th->doff ||
1786 memcmp(thtail + 1, th + 1, hdrlen - sizeof(*th)))
1787 goto no_coalesce;
1788
1789 __skb_pull(skb, hdrlen);
1790 if (skb_try_coalesce(tail, skb, &fragstolen, &delta)) {
1791 TCP_SKB_CB(tail)->end_seq = TCP_SKB_CB(skb)->end_seq;
1792
1793 if (likely(!before(TCP_SKB_CB(skb)->ack_seq, TCP_SKB_CB(tail)->ack_seq))) {
1794 TCP_SKB_CB(tail)->ack_seq = TCP_SKB_CB(skb)->ack_seq;
1795 thtail->window = th->window;
1796 }
1797
1798 /* We have to update both TCP_SKB_CB(tail)->tcp_flags and
1799 * thtail->fin, so that the fast path in tcp_rcv_established()
1800 * is not entered if we append a packet with a FIN.
1801 * SYN, RST, URG are not present.
1802 * ACK is set on both packets.
1803 * PSH : we do not really care in TCP stack,
1804 * at least for 'GRO' packets.
1805 */
1806 thtail->fin |= th->fin;
1807 TCP_SKB_CB(tail)->tcp_flags |= TCP_SKB_CB(skb)->tcp_flags;
1808
1809 if (TCP_SKB_CB(skb)->has_rxtstamp) {
1810 TCP_SKB_CB(tail)->has_rxtstamp = true;
1811 tail->tstamp = skb->tstamp;
1812 skb_hwtstamps(tail)->hwtstamp = skb_hwtstamps(skb)->hwtstamp;
1813 }
1814
1815 /* Not as strict as GRO. We only need to carry mss max value */
1816 skb_shinfo(tail)->gso_size = max(shinfo->gso_size,
1817 skb_shinfo(tail)->gso_size);
1818
1819 gso_segs = skb_shinfo(tail)->gso_segs + shinfo->gso_segs;
1820 skb_shinfo(tail)->gso_segs = min_t(u32, gso_segs, 0xFFFF);
1821
1822 sk->sk_backlog.len += delta;
1823 __NET_INC_STATS(sock_net(sk),
1824 LINUX_MIB_TCPBACKLOGCOALESCE);
1825 kfree_skb_partial(skb, fragstolen);
1826 return false;
1827 }
1828 __skb_push(skb, hdrlen);
1829
1830no_coalesce:
1831 /* Only socket owner can try to collapse/prune rx queues
1832 * to reduce memory overhead, so add a little headroom here.
1833 * Few sockets backlog are possibly concurrently non empty.
1834 */
1835 limit += 64*1024;
1836
1837 if (unlikely(sk_add_backlog(sk, skb, limit))) {
1838 bh_unlock_sock(sk);
1839 __NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPBACKLOGDROP);
1840 return true;
1841 }
1842 return false;
1843}
1844EXPORT_SYMBOL(tcp_add_backlog);
1845
1846int tcp_filter(struct sock *sk, struct sk_buff *skb)
1847{
1848 struct tcphdr *th = (struct tcphdr *)skb->data;
1849
1850 return sk_filter_trim_cap(sk, skb, th->doff * 4);
1851}
1852EXPORT_SYMBOL(tcp_filter);
1853
1854static void tcp_v4_restore_cb(struct sk_buff *skb)
1855{
1856 memmove(IPCB(skb), &TCP_SKB_CB(skb)->header.h4,
1857 sizeof(struct inet_skb_parm));
1858}
1859
1860static void tcp_v4_fill_cb(struct sk_buff *skb, const struct iphdr *iph,
1861 const struct tcphdr *th)
1862{
1863 /* This is tricky : We move IPCB at its correct location into TCP_SKB_CB()
1864 * barrier() makes sure compiler wont play fool^Waliasing games.
1865 */
1866 memmove(&TCP_SKB_CB(skb)->header.h4, IPCB(skb),
1867 sizeof(struct inet_skb_parm));
1868 barrier();
1869
1870 TCP_SKB_CB(skb)->seq = ntohl(th->seq);
1871 TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
1872 skb->len - th->doff * 4);
1873 TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
1874 TCP_SKB_CB(skb)->tcp_flags = tcp_flag_byte(th);
1875 TCP_SKB_CB(skb)->tcp_tw_isn = 0;
1876 TCP_SKB_CB(skb)->ip_dsfield = ipv4_get_dsfield(iph);
1877 TCP_SKB_CB(skb)->sacked = 0;
1878 TCP_SKB_CB(skb)->has_rxtstamp =
1879 skb->tstamp || skb_hwtstamps(skb)->hwtstamp;
1880}
1881
1882/*
1883 * From tcp_input.c
1884 */
1885
1886int tcp_v4_rcv(struct sk_buff *skb)
1887{
1888 struct net *net = dev_net(skb->dev);
1889 struct sk_buff *skb_to_free;
1890 int sdif = inet_sdif(skb);
1891 int dif = inet_iif(skb);
1892 const struct iphdr *iph;
1893 const struct tcphdr *th;
1894 bool refcounted;
1895 struct sock *sk;
1896 int ret;
1897
1898 if (skb->pkt_type != PACKET_HOST)
1899 goto discard_it;
1900
1901 /* Count it even if it's bad */
1902 __TCP_INC_STATS(net, TCP_MIB_INSEGS);
1903
1904 if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
1905 goto discard_it;
1906
1907 th = (const struct tcphdr *)skb->data;
1908
1909 if (unlikely(th->doff < sizeof(struct tcphdr) / 4))
1910 goto bad_packet;
1911 if (!pskb_may_pull(skb, th->doff * 4))
1912 goto discard_it;
1913
1914 /* An explanation is required here, I think.
1915 * Packet length and doff are validated by header prediction,
1916 * provided case of th->doff==0 is eliminated.
1917 * So, we defer the checks. */
1918
1919 if (skb_checksum_init(skb, IPPROTO_TCP, inet_compute_pseudo))
1920 goto csum_error;
1921
1922 th = (const struct tcphdr *)skb->data;
1923 iph = ip_hdr(skb);
1924lookup:
1925 sk = __inet_lookup_skb(&tcp_hashinfo, skb, __tcp_hdrlen(th), th->source,
1926 th->dest, sdif, &refcounted);
1927 if (!sk)
1928 goto no_tcp_socket;
1929
1930process:
1931 if (sk->sk_state == TCP_TIME_WAIT)
1932 goto do_time_wait;
1933
1934 if (sk->sk_state == TCP_NEW_SYN_RECV) {
1935 struct request_sock *req = inet_reqsk(sk);
1936 bool req_stolen = false;
1937 struct sock *nsk;
1938
1939 sk = req->rsk_listener;
1940 if (unlikely(tcp_v4_inbound_md5_hash(sk, skb, dif, sdif))) {
1941 sk_drops_add(sk, skb);
1942 reqsk_put(req);
1943 goto discard_it;
1944 }
1945 if (tcp_checksum_complete(skb)) {
1946 reqsk_put(req);
1947 goto csum_error;
1948 }
1949 if (unlikely(sk->sk_state != TCP_LISTEN)) {
1950 inet_csk_reqsk_queue_drop_and_put(sk, req);
1951 goto lookup;
1952 }
1953 /* We own a reference on the listener, increase it again
1954 * as we might lose it too soon.
1955 */
1956 sock_hold(sk);
1957 refcounted = true;
1958 nsk = NULL;
1959 if (!tcp_filter(sk, skb)) {
1960 th = (const struct tcphdr *)skb->data;
1961 iph = ip_hdr(skb);
1962 tcp_v4_fill_cb(skb, iph, th);
1963 nsk = tcp_check_req(sk, skb, req, false, &req_stolen);
1964 }
1965 if (!nsk) {
1966 reqsk_put(req);
1967 if (req_stolen) {
1968 /* Another cpu got exclusive access to req
1969 * and created a full blown socket.
1970 * Try to feed this packet to this socket
1971 * instead of discarding it.
1972 */
1973 tcp_v4_restore_cb(skb);
1974 sock_put(sk);
1975 goto lookup;
1976 }
1977 goto discard_and_relse;
1978 }
1979 if (nsk == sk) {
1980 reqsk_put(req);
1981 tcp_v4_restore_cb(skb);
1982 } else if (tcp_child_process(sk, nsk, skb)) {
1983 tcp_v4_send_reset(nsk, skb);
1984 goto discard_and_relse;
1985 } else {
1986 sock_put(sk);
1987 return 0;
1988 }
1989 }
1990 if (unlikely(iph->ttl < inet_sk(sk)->min_ttl)) {
1991 __NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP);
1992 goto discard_and_relse;
1993 }
1994
1995 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
1996 goto discard_and_relse;
1997
1998 if (tcp_v4_inbound_md5_hash(sk, skb, dif, sdif))
1999 goto discard_and_relse;
2000
2001 nf_reset_ct(skb);
2002
2003 if (tcp_filter(sk, skb))
2004 goto discard_and_relse;
2005 th = (const struct tcphdr *)skb->data;
2006 iph = ip_hdr(skb);
2007 tcp_v4_fill_cb(skb, iph, th);
2008
2009 skb->dev = NULL;
2010
2011 if (sk->sk_state == TCP_LISTEN) {
2012 ret = tcp_v4_do_rcv(sk, skb);
2013 goto put_and_return;
2014 }
2015
2016 sk_incoming_cpu_update(sk);
2017
2018 bh_lock_sock_nested(sk);
2019 tcp_segs_in(tcp_sk(sk), skb);
2020 ret = 0;
2021 if (!sock_owned_by_user(sk)) {
2022 skb_to_free = sk->sk_rx_skb_cache;
2023 sk->sk_rx_skb_cache = NULL;
2024 ret = tcp_v4_do_rcv(sk, skb);
2025 } else {
2026 if (tcp_add_backlog(sk, skb))
2027 goto discard_and_relse;
2028 skb_to_free = NULL;
2029 }
2030 bh_unlock_sock(sk);
2031 if (skb_to_free)
2032 __kfree_skb(skb_to_free);
2033
2034put_and_return:
2035 if (refcounted)
2036 sock_put(sk);
2037
2038 return ret;
2039
2040no_tcp_socket:
2041 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
2042 goto discard_it;
2043
2044 tcp_v4_fill_cb(skb, iph, th);
2045
2046 if (tcp_checksum_complete(skb)) {
2047csum_error:
2048 __TCP_INC_STATS(net, TCP_MIB_CSUMERRORS);
2049bad_packet:
2050 __TCP_INC_STATS(net, TCP_MIB_INERRS);
2051 } else {
2052 tcp_v4_send_reset(NULL, skb);
2053 }
2054
2055discard_it:
2056 /* Discard frame. */
2057 kfree_skb(skb);
2058 return 0;
2059
2060discard_and_relse:
2061 sk_drops_add(sk, skb);
2062 if (refcounted)
2063 sock_put(sk);
2064 goto discard_it;
2065
2066do_time_wait:
2067 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
2068 inet_twsk_put(inet_twsk(sk));
2069 goto discard_it;
2070 }
2071
2072 tcp_v4_fill_cb(skb, iph, th);
2073
2074 if (tcp_checksum_complete(skb)) {
2075 inet_twsk_put(inet_twsk(sk));
2076 goto csum_error;
2077 }
2078 switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) {
2079 case TCP_TW_SYN: {
2080 struct sock *sk2 = inet_lookup_listener(dev_net(skb->dev),
2081 &tcp_hashinfo, skb,
2082 __tcp_hdrlen(th),
2083 iph->saddr, th->source,
2084 iph->daddr, th->dest,
2085 inet_iif(skb),
2086 sdif);
2087 if (sk2) {
2088 inet_twsk_deschedule_put(inet_twsk(sk));
2089 sk = sk2;
2090 tcp_v4_restore_cb(skb);
2091 refcounted = false;
2092 goto process;
2093 }
2094 }
2095 /* to ACK */
2096 fallthrough;
2097 case TCP_TW_ACK:
2098 tcp_v4_timewait_ack(sk, skb);
2099 break;
2100 case TCP_TW_RST:
2101 tcp_v4_send_reset(sk, skb);
2102 inet_twsk_deschedule_put(inet_twsk(sk));
2103 goto discard_it;
2104 case TCP_TW_SUCCESS:;
2105 }
2106 goto discard_it;
2107}
2108
2109static struct timewait_sock_ops tcp_timewait_sock_ops = {
2110 .twsk_obj_size = sizeof(struct tcp_timewait_sock),
2111 .twsk_unique = tcp_twsk_unique,
2112 .twsk_destructor= tcp_twsk_destructor,
2113};
2114
2115void inet_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb)
2116{
2117 struct dst_entry *dst = skb_dst(skb);
2118
2119 if (dst && dst_hold_safe(dst)) {
2120 sk->sk_rx_dst = dst;
2121 inet_sk(sk)->rx_dst_ifindex = skb->skb_iif;
2122 }
2123}
2124EXPORT_SYMBOL(inet_sk_rx_dst_set);
2125
2126const struct inet_connection_sock_af_ops ipv4_specific = {
2127 .queue_xmit = ip_queue_xmit,
2128 .send_check = tcp_v4_send_check,
2129 .rebuild_header = inet_sk_rebuild_header,
2130 .sk_rx_dst_set = inet_sk_rx_dst_set,
2131 .conn_request = tcp_v4_conn_request,
2132 .syn_recv_sock = tcp_v4_syn_recv_sock,
2133 .net_header_len = sizeof(struct iphdr),
2134 .setsockopt = ip_setsockopt,
2135 .getsockopt = ip_getsockopt,
2136 .addr2sockaddr = inet_csk_addr2sockaddr,
2137 .sockaddr_len = sizeof(struct sockaddr_in),
2138 .mtu_reduced = tcp_v4_mtu_reduced,
2139};
2140EXPORT_SYMBOL(ipv4_specific);
2141
2142#ifdef CONFIG_TCP_MD5SIG
2143static const struct tcp_sock_af_ops tcp_sock_ipv4_specific = {
2144 .md5_lookup = tcp_v4_md5_lookup,
2145 .calc_md5_hash = tcp_v4_md5_hash_skb,
2146 .md5_parse = tcp_v4_parse_md5_keys,
2147};
2148#endif
2149
2150/* NOTE: A lot of things set to zero explicitly by call to
2151 * sk_alloc() so need not be done here.
2152 */
2153static int tcp_v4_init_sock(struct sock *sk)
2154{
2155 struct inet_connection_sock *icsk = inet_csk(sk);
2156
2157 tcp_init_sock(sk);
2158
2159 icsk->icsk_af_ops = &ipv4_specific;
2160
2161#ifdef CONFIG_TCP_MD5SIG
2162 tcp_sk(sk)->af_specific = &tcp_sock_ipv4_specific;
2163#endif
2164
2165 return 0;
2166}
2167
2168void tcp_v4_destroy_sock(struct sock *sk)
2169{
2170 struct tcp_sock *tp = tcp_sk(sk);
2171
2172 trace_tcp_destroy_sock(sk);
2173
2174 tcp_clear_xmit_timers(sk);
2175
2176 tcp_cleanup_congestion_control(sk);
2177
2178 tcp_cleanup_ulp(sk);
2179
2180 /* Cleanup up the write buffer. */
2181 tcp_write_queue_purge(sk);
2182
2183 /* Check if we want to disable active TFO */
2184 tcp_fastopen_active_disable_ofo_check(sk);
2185
2186 /* Cleans up our, hopefully empty, out_of_order_queue. */
2187 skb_rbtree_purge(&tp->out_of_order_queue);
2188
2189#ifdef CONFIG_TCP_MD5SIG
2190 /* Clean up the MD5 key list, if any */
2191 if (tp->md5sig_info) {
2192 tcp_clear_md5_list(sk);
2193 kfree_rcu(rcu_dereference_protected(tp->md5sig_info, 1), rcu);
2194 tp->md5sig_info = NULL;
2195 }
2196#endif
2197
2198 /* Clean up a referenced TCP bind bucket. */
2199 if (inet_csk(sk)->icsk_bind_hash)
2200 inet_put_port(sk);
2201
2202 BUG_ON(rcu_access_pointer(tp->fastopen_rsk));
2203
2204 /* If socket is aborted during connect operation */
2205 tcp_free_fastopen_req(tp);
2206 tcp_fastopen_destroy_cipher(sk);
2207 tcp_saved_syn_free(tp);
2208
2209 sk_sockets_allocated_dec(sk);
2210}
2211EXPORT_SYMBOL(tcp_v4_destroy_sock);
2212
2213#ifdef CONFIG_PROC_FS
2214/* Proc filesystem TCP sock list dumping. */
2215
2216/*
2217 * Get next listener socket follow cur. If cur is NULL, get first socket
2218 * starting from bucket given in st->bucket; when st->bucket is zero the
2219 * very first socket in the hash table is returned.
2220 */
2221static void *listening_get_next(struct seq_file *seq, void *cur)
2222{
2223 struct tcp_seq_afinfo *afinfo;
2224 struct tcp_iter_state *st = seq->private;
2225 struct net *net = seq_file_net(seq);
2226 struct inet_listen_hashbucket *ilb;
2227 struct hlist_nulls_node *node;
2228 struct sock *sk = cur;
2229
2230 if (st->bpf_seq_afinfo)
2231 afinfo = st->bpf_seq_afinfo;
2232 else
2233 afinfo = PDE_DATA(file_inode(seq->file));
2234
2235 if (!sk) {
2236get_head:
2237 ilb = &tcp_hashinfo.listening_hash[st->bucket];
2238 spin_lock(&ilb->lock);
2239 sk = sk_nulls_head(&ilb->nulls_head);
2240 st->offset = 0;
2241 goto get_sk;
2242 }
2243 ilb = &tcp_hashinfo.listening_hash[st->bucket];
2244 ++st->num;
2245 ++st->offset;
2246
2247 sk = sk_nulls_next(sk);
2248get_sk:
2249 sk_nulls_for_each_from(sk, node) {
2250 if (!net_eq(sock_net(sk), net))
2251 continue;
2252 if (afinfo->family == AF_UNSPEC ||
2253 sk->sk_family == afinfo->family)
2254 return sk;
2255 }
2256 spin_unlock(&ilb->lock);
2257 st->offset = 0;
2258 if (++st->bucket < INET_LHTABLE_SIZE)
2259 goto get_head;
2260 return NULL;
2261}
2262
2263static void *listening_get_idx(struct seq_file *seq, loff_t *pos)
2264{
2265 struct tcp_iter_state *st = seq->private;
2266 void *rc;
2267
2268 st->bucket = 0;
2269 st->offset = 0;
2270 rc = listening_get_next(seq, NULL);
2271
2272 while (rc && *pos) {
2273 rc = listening_get_next(seq, rc);
2274 --*pos;
2275 }
2276 return rc;
2277}
2278
2279static inline bool empty_bucket(const struct tcp_iter_state *st)
2280{
2281 return hlist_nulls_empty(&tcp_hashinfo.ehash[st->bucket].chain);
2282}
2283
2284/*
2285 * Get first established socket starting from bucket given in st->bucket.
2286 * If st->bucket is zero, the very first socket in the hash is returned.
2287 */
2288static void *established_get_first(struct seq_file *seq)
2289{
2290 struct tcp_seq_afinfo *afinfo;
2291 struct tcp_iter_state *st = seq->private;
2292 struct net *net = seq_file_net(seq);
2293 void *rc = NULL;
2294
2295 if (st->bpf_seq_afinfo)
2296 afinfo = st->bpf_seq_afinfo;
2297 else
2298 afinfo = PDE_DATA(file_inode(seq->file));
2299
2300 st->offset = 0;
2301 for (; st->bucket <= tcp_hashinfo.ehash_mask; ++st->bucket) {
2302 struct sock *sk;
2303 struct hlist_nulls_node *node;
2304 spinlock_t *lock = inet_ehash_lockp(&tcp_hashinfo, st->bucket);
2305
2306 /* Lockless fast path for the common case of empty buckets */
2307 if (empty_bucket(st))
2308 continue;
2309
2310 spin_lock_bh(lock);
2311 sk_nulls_for_each(sk, node, &tcp_hashinfo.ehash[st->bucket].chain) {
2312 if ((afinfo->family != AF_UNSPEC &&
2313 sk->sk_family != afinfo->family) ||
2314 !net_eq(sock_net(sk), net)) {
2315 continue;
2316 }
2317 rc = sk;
2318 goto out;
2319 }
2320 spin_unlock_bh(lock);
2321 }
2322out:
2323 return rc;
2324}
2325
2326static void *established_get_next(struct seq_file *seq, void *cur)
2327{
2328 struct tcp_seq_afinfo *afinfo;
2329 struct sock *sk = cur;
2330 struct hlist_nulls_node *node;
2331 struct tcp_iter_state *st = seq->private;
2332 struct net *net = seq_file_net(seq);
2333
2334 if (st->bpf_seq_afinfo)
2335 afinfo = st->bpf_seq_afinfo;
2336 else
2337 afinfo = PDE_DATA(file_inode(seq->file));
2338
2339 ++st->num;
2340 ++st->offset;
2341
2342 sk = sk_nulls_next(sk);
2343
2344 sk_nulls_for_each_from(sk, node) {
2345 if ((afinfo->family == AF_UNSPEC ||
2346 sk->sk_family == afinfo->family) &&
2347 net_eq(sock_net(sk), net))
2348 return sk;
2349 }
2350
2351 spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
2352 ++st->bucket;
2353 return established_get_first(seq);
2354}
2355
2356static void *established_get_idx(struct seq_file *seq, loff_t pos)
2357{
2358 struct tcp_iter_state *st = seq->private;
2359 void *rc;
2360
2361 st->bucket = 0;
2362 rc = established_get_first(seq);
2363
2364 while (rc && pos) {
2365 rc = established_get_next(seq, rc);
2366 --pos;
2367 }
2368 return rc;
2369}
2370
2371static void *tcp_get_idx(struct seq_file *seq, loff_t pos)
2372{
2373 void *rc;
2374 struct tcp_iter_state *st = seq->private;
2375
2376 st->state = TCP_SEQ_STATE_LISTENING;
2377 rc = listening_get_idx(seq, &pos);
2378
2379 if (!rc) {
2380 st->state = TCP_SEQ_STATE_ESTABLISHED;
2381 rc = established_get_idx(seq, pos);
2382 }
2383
2384 return rc;
2385}
2386
2387static void *tcp_seek_last_pos(struct seq_file *seq)
2388{
2389 struct tcp_iter_state *st = seq->private;
2390 int offset = st->offset;
2391 int orig_num = st->num;
2392 void *rc = NULL;
2393
2394 switch (st->state) {
2395 case TCP_SEQ_STATE_LISTENING:
2396 if (st->bucket >= INET_LHTABLE_SIZE)
2397 break;
2398 st->state = TCP_SEQ_STATE_LISTENING;
2399 rc = listening_get_next(seq, NULL);
2400 while (offset-- && rc)
2401 rc = listening_get_next(seq, rc);
2402 if (rc)
2403 break;
2404 st->bucket = 0;
2405 st->state = TCP_SEQ_STATE_ESTABLISHED;
2406 fallthrough;
2407 case TCP_SEQ_STATE_ESTABLISHED:
2408 if (st->bucket > tcp_hashinfo.ehash_mask)
2409 break;
2410 rc = established_get_first(seq);
2411 while (offset-- && rc)
2412 rc = established_get_next(seq, rc);
2413 }
2414
2415 st->num = orig_num;
2416
2417 return rc;
2418}
2419
2420void *tcp_seq_start(struct seq_file *seq, loff_t *pos)
2421{
2422 struct tcp_iter_state *st = seq->private;
2423 void *rc;
2424
2425 if (*pos && *pos == st->last_pos) {
2426 rc = tcp_seek_last_pos(seq);
2427 if (rc)
2428 goto out;
2429 }
2430
2431 st->state = TCP_SEQ_STATE_LISTENING;
2432 st->num = 0;
2433 st->bucket = 0;
2434 st->offset = 0;
2435 rc = *pos ? tcp_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
2436
2437out:
2438 st->last_pos = *pos;
2439 return rc;
2440}
2441EXPORT_SYMBOL(tcp_seq_start);
2442
2443void *tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2444{
2445 struct tcp_iter_state *st = seq->private;
2446 void *rc = NULL;
2447
2448 if (v == SEQ_START_TOKEN) {
2449 rc = tcp_get_idx(seq, 0);
2450 goto out;
2451 }
2452
2453 switch (st->state) {
2454 case TCP_SEQ_STATE_LISTENING:
2455 rc = listening_get_next(seq, v);
2456 if (!rc) {
2457 st->state = TCP_SEQ_STATE_ESTABLISHED;
2458 st->bucket = 0;
2459 st->offset = 0;
2460 rc = established_get_first(seq);
2461 }
2462 break;
2463 case TCP_SEQ_STATE_ESTABLISHED:
2464 rc = established_get_next(seq, v);
2465 break;
2466 }
2467out:
2468 ++*pos;
2469 st->last_pos = *pos;
2470 return rc;
2471}
2472EXPORT_SYMBOL(tcp_seq_next);
2473
2474void tcp_seq_stop(struct seq_file *seq, void *v)
2475{
2476 struct tcp_iter_state *st = seq->private;
2477
2478 switch (st->state) {
2479 case TCP_SEQ_STATE_LISTENING:
2480 if (v != SEQ_START_TOKEN)
2481 spin_unlock(&tcp_hashinfo.listening_hash[st->bucket].lock);
2482 break;
2483 case TCP_SEQ_STATE_ESTABLISHED:
2484 if (v)
2485 spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
2486 break;
2487 }
2488}
2489EXPORT_SYMBOL(tcp_seq_stop);
2490
2491static void get_openreq4(const struct request_sock *req,
2492 struct seq_file *f, int i)
2493{
2494 const struct inet_request_sock *ireq = inet_rsk(req);
2495 long delta = req->rsk_timer.expires - jiffies;
2496
2497 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2498 " %02X %08X:%08X %02X:%08lX %08X %5u %8d %u %d %pK",
2499 i,
2500 ireq->ir_loc_addr,
2501 ireq->ir_num,
2502 ireq->ir_rmt_addr,
2503 ntohs(ireq->ir_rmt_port),
2504 TCP_SYN_RECV,
2505 0, 0, /* could print option size, but that is af dependent. */
2506 1, /* timers active (only the expire timer) */
2507 jiffies_delta_to_clock_t(delta),
2508 req->num_timeout,
2509 from_kuid_munged(seq_user_ns(f),
2510 sock_i_uid(req->rsk_listener)),
2511 0, /* non standard timer */
2512 0, /* open_requests have no inode */
2513 0,
2514 req);
2515}
2516
2517static void get_tcp4_sock(struct sock *sk, struct seq_file *f, int i)
2518{
2519 int timer_active;
2520 unsigned long timer_expires;
2521 const struct tcp_sock *tp = tcp_sk(sk);
2522 const struct inet_connection_sock *icsk = inet_csk(sk);
2523 const struct inet_sock *inet = inet_sk(sk);
2524 const struct fastopen_queue *fastopenq = &icsk->icsk_accept_queue.fastopenq;
2525 __be32 dest = inet->inet_daddr;
2526 __be32 src = inet->inet_rcv_saddr;
2527 __u16 destp = ntohs(inet->inet_dport);
2528 __u16 srcp = ntohs(inet->inet_sport);
2529 int rx_queue;
2530 int state;
2531
2532 if (icsk->icsk_pending == ICSK_TIME_RETRANS ||
2533 icsk->icsk_pending == ICSK_TIME_REO_TIMEOUT ||
2534 icsk->icsk_pending == ICSK_TIME_LOSS_PROBE) {
2535 timer_active = 1;
2536 timer_expires = icsk->icsk_timeout;
2537 } else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
2538 timer_active = 4;
2539 timer_expires = icsk->icsk_timeout;
2540 } else if (timer_pending(&sk->sk_timer)) {
2541 timer_active = 2;
2542 timer_expires = sk->sk_timer.expires;
2543 } else {
2544 timer_active = 0;
2545 timer_expires = jiffies;
2546 }
2547
2548 state = inet_sk_state_load(sk);
2549 if (state == TCP_LISTEN)
2550 rx_queue = READ_ONCE(sk->sk_ack_backlog);
2551 else
2552 /* Because we don't lock the socket,
2553 * we might find a transient negative value.
2554 */
2555 rx_queue = max_t(int, READ_ONCE(tp->rcv_nxt) -
2556 READ_ONCE(tp->copied_seq), 0);
2557
2558 seq_printf(f, "%4d: %08X:%04X %08X:%04X %02X %08X:%08X %02X:%08lX "
2559 "%08X %5u %8d %lu %d %pK %lu %lu %u %u %d",
2560 i, src, srcp, dest, destp, state,
2561 READ_ONCE(tp->write_seq) - tp->snd_una,
2562 rx_queue,
2563 timer_active,
2564 jiffies_delta_to_clock_t(timer_expires - jiffies),
2565 icsk->icsk_retransmits,
2566 from_kuid_munged(seq_user_ns(f), sock_i_uid(sk)),
2567 icsk->icsk_probes_out,
2568 sock_i_ino(sk),
2569 refcount_read(&sk->sk_refcnt), sk,
2570 jiffies_to_clock_t(icsk->icsk_rto),
2571 jiffies_to_clock_t(icsk->icsk_ack.ato),
2572 (icsk->icsk_ack.quick << 1) | inet_csk_in_pingpong_mode(sk),
2573 tp->snd_cwnd,
2574 state == TCP_LISTEN ?
2575 fastopenq->max_qlen :
2576 (tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh));
2577}
2578
2579static void get_timewait4_sock(const struct inet_timewait_sock *tw,
2580 struct seq_file *f, int i)
2581{
2582 long delta = tw->tw_timer.expires - jiffies;
2583 __be32 dest, src;
2584 __u16 destp, srcp;
2585
2586 dest = tw->tw_daddr;
2587 src = tw->tw_rcv_saddr;
2588 destp = ntohs(tw->tw_dport);
2589 srcp = ntohs(tw->tw_sport);
2590
2591 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2592 " %02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK",
2593 i, src, srcp, dest, destp, tw->tw_substate, 0, 0,
2594 3, jiffies_delta_to_clock_t(delta), 0, 0, 0, 0,
2595 refcount_read(&tw->tw_refcnt), tw);
2596}
2597
2598#define TMPSZ 150
2599
2600static int tcp4_seq_show(struct seq_file *seq, void *v)
2601{
2602 struct tcp_iter_state *st;
2603 struct sock *sk = v;
2604
2605 seq_setwidth(seq, TMPSZ - 1);
2606 if (v == SEQ_START_TOKEN) {
2607 seq_puts(seq, " sl local_address rem_address st tx_queue "
2608 "rx_queue tr tm->when retrnsmt uid timeout "
2609 "inode");
2610 goto out;
2611 }
2612 st = seq->private;
2613
2614 if (sk->sk_state == TCP_TIME_WAIT)
2615 get_timewait4_sock(v, seq, st->num);
2616 else if (sk->sk_state == TCP_NEW_SYN_RECV)
2617 get_openreq4(v, seq, st->num);
2618 else
2619 get_tcp4_sock(v, seq, st->num);
2620out:
2621 seq_pad(seq, '\n');
2622 return 0;
2623}
2624
2625#ifdef CONFIG_BPF_SYSCALL
2626struct bpf_iter__tcp {
2627 __bpf_md_ptr(struct bpf_iter_meta *, meta);
2628 __bpf_md_ptr(struct sock_common *, sk_common);
2629 uid_t uid __aligned(8);
2630};
2631
2632static int tcp_prog_seq_show(struct bpf_prog *prog, struct bpf_iter_meta *meta,
2633 struct sock_common *sk_common, uid_t uid)
2634{
2635 struct bpf_iter__tcp ctx;
2636
2637 meta->seq_num--; /* skip SEQ_START_TOKEN */
2638 ctx.meta = meta;
2639 ctx.sk_common = sk_common;
2640 ctx.uid = uid;
2641 return bpf_iter_run_prog(prog, &ctx);
2642}
2643
2644static int bpf_iter_tcp_seq_show(struct seq_file *seq, void *v)
2645{
2646 struct bpf_iter_meta meta;
2647 struct bpf_prog *prog;
2648 struct sock *sk = v;
2649 uid_t uid;
2650
2651 if (v == SEQ_START_TOKEN)
2652 return 0;
2653
2654 if (sk->sk_state == TCP_TIME_WAIT) {
2655 uid = 0;
2656 } else if (sk->sk_state == TCP_NEW_SYN_RECV) {
2657 const struct request_sock *req = v;
2658
2659 uid = from_kuid_munged(seq_user_ns(seq),
2660 sock_i_uid(req->rsk_listener));
2661 } else {
2662 uid = from_kuid_munged(seq_user_ns(seq), sock_i_uid(sk));
2663 }
2664
2665 meta.seq = seq;
2666 prog = bpf_iter_get_info(&meta, false);
2667 return tcp_prog_seq_show(prog, &meta, v, uid);
2668}
2669
2670static void bpf_iter_tcp_seq_stop(struct seq_file *seq, void *v)
2671{
2672 struct bpf_iter_meta meta;
2673 struct bpf_prog *prog;
2674
2675 if (!v) {
2676 meta.seq = seq;
2677 prog = bpf_iter_get_info(&meta, true);
2678 if (prog)
2679 (void)tcp_prog_seq_show(prog, &meta, v, 0);
2680 }
2681
2682 tcp_seq_stop(seq, v);
2683}
2684
2685static const struct seq_operations bpf_iter_tcp_seq_ops = {
2686 .show = bpf_iter_tcp_seq_show,
2687 .start = tcp_seq_start,
2688 .next = tcp_seq_next,
2689 .stop = bpf_iter_tcp_seq_stop,
2690};
2691#endif
2692
2693static const struct seq_operations tcp4_seq_ops = {
2694 .show = tcp4_seq_show,
2695 .start = tcp_seq_start,
2696 .next = tcp_seq_next,
2697 .stop = tcp_seq_stop,
2698};
2699
2700static struct tcp_seq_afinfo tcp4_seq_afinfo = {
2701 .family = AF_INET,
2702};
2703
2704static int __net_init tcp4_proc_init_net(struct net *net)
2705{
2706 if (!proc_create_net_data("tcp", 0444, net->proc_net, &tcp4_seq_ops,
2707 sizeof(struct tcp_iter_state), &tcp4_seq_afinfo))
2708 return -ENOMEM;
2709 return 0;
2710}
2711
2712static void __net_exit tcp4_proc_exit_net(struct net *net)
2713{
2714 remove_proc_entry("tcp", net->proc_net);
2715}
2716
2717static struct pernet_operations tcp4_net_ops = {
2718 .init = tcp4_proc_init_net,
2719 .exit = tcp4_proc_exit_net,
2720};
2721
2722int __init tcp4_proc_init(void)
2723{
2724 return register_pernet_subsys(&tcp4_net_ops);
2725}
2726
2727void tcp4_proc_exit(void)
2728{
2729 unregister_pernet_subsys(&tcp4_net_ops);
2730}
2731#endif /* CONFIG_PROC_FS */
2732
2733struct proto tcp_prot = {
2734 .name = "TCP",
2735 .owner = THIS_MODULE,
2736 .close = tcp_close,
2737 .pre_connect = tcp_v4_pre_connect,
2738 .connect = tcp_v4_connect,
2739 .disconnect = tcp_disconnect,
2740 .accept = inet_csk_accept,
2741 .ioctl = tcp_ioctl,
2742 .init = tcp_v4_init_sock,
2743 .destroy = tcp_v4_destroy_sock,
2744 .shutdown = tcp_shutdown,
2745 .setsockopt = tcp_setsockopt,
2746 .getsockopt = tcp_getsockopt,
2747 .keepalive = tcp_set_keepalive,
2748 .recvmsg = tcp_recvmsg,
2749 .sendmsg = tcp_sendmsg,
2750 .sendpage = tcp_sendpage,
2751 .backlog_rcv = tcp_v4_do_rcv,
2752 .release_cb = tcp_release_cb,
2753 .hash = inet_hash,
2754 .unhash = inet_unhash,
2755 .get_port = inet_csk_get_port,
2756 .enter_memory_pressure = tcp_enter_memory_pressure,
2757 .leave_memory_pressure = tcp_leave_memory_pressure,
2758 .stream_memory_free = tcp_stream_memory_free,
2759 .sockets_allocated = &tcp_sockets_allocated,
2760 .orphan_count = &tcp_orphan_count,
2761 .memory_allocated = &tcp_memory_allocated,
2762 .memory_pressure = &tcp_memory_pressure,
2763 .sysctl_mem = sysctl_tcp_mem,
2764 .sysctl_wmem_offset = offsetof(struct net, ipv4.sysctl_tcp_wmem),
2765 .sysctl_rmem_offset = offsetof(struct net, ipv4.sysctl_tcp_rmem),
2766 .max_header = MAX_TCP_HEADER,
2767 .obj_size = sizeof(struct tcp_sock),
2768 .slab_flags = SLAB_TYPESAFE_BY_RCU,
2769 .twsk_prot = &tcp_timewait_sock_ops,
2770 .rsk_prot = &tcp_request_sock_ops,
2771 .h.hashinfo = &tcp_hashinfo,
2772 .no_autobind = true,
2773 .diag_destroy = tcp_abort,
2774};
2775EXPORT_SYMBOL(tcp_prot);
2776
2777static void __net_exit tcp_sk_exit(struct net *net)
2778{
2779 int cpu;
2780
2781 if (net->ipv4.tcp_congestion_control)
2782 bpf_module_put(net->ipv4.tcp_congestion_control,
2783 net->ipv4.tcp_congestion_control->owner);
2784
2785 for_each_possible_cpu(cpu)
2786 inet_ctl_sock_destroy(*per_cpu_ptr(net->ipv4.tcp_sk, cpu));
2787 free_percpu(net->ipv4.tcp_sk);
2788}
2789
2790static int __net_init tcp_sk_init(struct net *net)
2791{
2792 int res, cpu, cnt;
2793
2794 net->ipv4.tcp_sk = alloc_percpu(struct sock *);
2795 if (!net->ipv4.tcp_sk)
2796 return -ENOMEM;
2797
2798 for_each_possible_cpu(cpu) {
2799 struct sock *sk;
2800
2801 res = inet_ctl_sock_create(&sk, PF_INET, SOCK_RAW,
2802 IPPROTO_TCP, net);
2803 if (res)
2804 goto fail;
2805 sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
2806
2807 /* Please enforce IP_DF and IPID==0 for RST and
2808 * ACK sent in SYN-RECV and TIME-WAIT state.
2809 */
2810 inet_sk(sk)->pmtudisc = IP_PMTUDISC_DO;
2811
2812 *per_cpu_ptr(net->ipv4.tcp_sk, cpu) = sk;
2813 }
2814
2815 net->ipv4.sysctl_tcp_ecn = 2;
2816 net->ipv4.sysctl_tcp_ecn_fallback = 1;
2817
2818 net->ipv4.sysctl_tcp_base_mss = TCP_BASE_MSS;
2819 net->ipv4.sysctl_tcp_min_snd_mss = TCP_MIN_SND_MSS;
2820 net->ipv4.sysctl_tcp_probe_threshold = TCP_PROBE_THRESHOLD;
2821 net->ipv4.sysctl_tcp_probe_interval = TCP_PROBE_INTERVAL;
2822 net->ipv4.sysctl_tcp_mtu_probe_floor = TCP_MIN_SND_MSS;
2823
2824 net->ipv4.sysctl_tcp_keepalive_time = TCP_KEEPALIVE_TIME;
2825 net->ipv4.sysctl_tcp_keepalive_probes = TCP_KEEPALIVE_PROBES;
2826 net->ipv4.sysctl_tcp_keepalive_intvl = TCP_KEEPALIVE_INTVL;
2827
2828 net->ipv4.sysctl_tcp_syn_retries = TCP_SYN_RETRIES;
2829 net->ipv4.sysctl_tcp_synack_retries = TCP_SYNACK_RETRIES;
2830 net->ipv4.sysctl_tcp_syncookies = 1;
2831 net->ipv4.sysctl_tcp_reordering = TCP_FASTRETRANS_THRESH;
2832 net->ipv4.sysctl_tcp_retries1 = TCP_RETR1;
2833 net->ipv4.sysctl_tcp_retries2 = TCP_RETR2;
2834 net->ipv4.sysctl_tcp_orphan_retries = 0;
2835 net->ipv4.sysctl_tcp_fin_timeout = TCP_FIN_TIMEOUT;
2836 net->ipv4.sysctl_tcp_notsent_lowat = UINT_MAX;
2837 net->ipv4.sysctl_tcp_tw_reuse = 2;
2838 net->ipv4.sysctl_tcp_no_ssthresh_metrics_save = 1;
2839
2840 cnt = tcp_hashinfo.ehash_mask + 1;
2841 net->ipv4.tcp_death_row.sysctl_max_tw_buckets = cnt / 2;
2842 net->ipv4.tcp_death_row.hashinfo = &tcp_hashinfo;
2843
2844 net->ipv4.sysctl_max_syn_backlog = max(128, cnt / 128);
2845 net->ipv4.sysctl_tcp_sack = 1;
2846 net->ipv4.sysctl_tcp_window_scaling = 1;
2847 net->ipv4.sysctl_tcp_timestamps = 1;
2848 net->ipv4.sysctl_tcp_early_retrans = 3;
2849 net->ipv4.sysctl_tcp_recovery = TCP_RACK_LOSS_DETECTION;
2850 net->ipv4.sysctl_tcp_slow_start_after_idle = 1; /* By default, RFC2861 behavior. */
2851 net->ipv4.sysctl_tcp_retrans_collapse = 1;
2852 net->ipv4.sysctl_tcp_max_reordering = 300;
2853 net->ipv4.sysctl_tcp_dsack = 1;
2854 net->ipv4.sysctl_tcp_app_win = 31;
2855 net->ipv4.sysctl_tcp_adv_win_scale = 1;
2856 net->ipv4.sysctl_tcp_frto = 2;
2857 net->ipv4.sysctl_tcp_moderate_rcvbuf = 1;
2858 /* This limits the percentage of the congestion window which we
2859 * will allow a single TSO frame to consume. Building TSO frames
2860 * which are too large can cause TCP streams to be bursty.
2861 */
2862 net->ipv4.sysctl_tcp_tso_win_divisor = 3;
2863 /* Default TSQ limit of 16 TSO segments */
2864 net->ipv4.sysctl_tcp_limit_output_bytes = 16 * 65536;
2865 /* rfc5961 challenge ack rate limiting */
2866 net->ipv4.sysctl_tcp_challenge_ack_limit = 1000;
2867 net->ipv4.sysctl_tcp_min_tso_segs = 2;
2868 net->ipv4.sysctl_tcp_min_rtt_wlen = 300;
2869 net->ipv4.sysctl_tcp_autocorking = 1;
2870 net->ipv4.sysctl_tcp_invalid_ratelimit = HZ/2;
2871 net->ipv4.sysctl_tcp_pacing_ss_ratio = 200;
2872 net->ipv4.sysctl_tcp_pacing_ca_ratio = 120;
2873 if (net != &init_net) {
2874 memcpy(net->ipv4.sysctl_tcp_rmem,
2875 init_net.ipv4.sysctl_tcp_rmem,
2876 sizeof(init_net.ipv4.sysctl_tcp_rmem));
2877 memcpy(net->ipv4.sysctl_tcp_wmem,
2878 init_net.ipv4.sysctl_tcp_wmem,
2879 sizeof(init_net.ipv4.sysctl_tcp_wmem));
2880 }
2881 net->ipv4.sysctl_tcp_comp_sack_delay_ns = NSEC_PER_MSEC;
2882 net->ipv4.sysctl_tcp_comp_sack_slack_ns = 100 * NSEC_PER_USEC;
2883 net->ipv4.sysctl_tcp_comp_sack_nr = 44;
2884 net->ipv4.sysctl_tcp_fastopen = TFO_CLIENT_ENABLE;
2885 spin_lock_init(&net->ipv4.tcp_fastopen_ctx_lock);
2886 net->ipv4.sysctl_tcp_fastopen_blackhole_timeout = 60 * 60;
2887 atomic_set(&net->ipv4.tfo_active_disable_times, 0);
2888
2889 /* Reno is always built in */
2890 if (!net_eq(net, &init_net) &&
2891 bpf_try_module_get(init_net.ipv4.tcp_congestion_control,
2892 init_net.ipv4.tcp_congestion_control->owner))
2893 net->ipv4.tcp_congestion_control = init_net.ipv4.tcp_congestion_control;
2894 else
2895 net->ipv4.tcp_congestion_control = &tcp_reno;
2896
2897 return 0;
2898fail:
2899 tcp_sk_exit(net);
2900
2901 return res;
2902}
2903
2904static void __net_exit tcp_sk_exit_batch(struct list_head *net_exit_list)
2905{
2906 struct net *net;
2907
2908 inet_twsk_purge(&tcp_hashinfo, AF_INET);
2909
2910 list_for_each_entry(net, net_exit_list, exit_list)
2911 tcp_fastopen_ctx_destroy(net);
2912}
2913
2914static struct pernet_operations __net_initdata tcp_sk_ops = {
2915 .init = tcp_sk_init,
2916 .exit = tcp_sk_exit,
2917 .exit_batch = tcp_sk_exit_batch,
2918};
2919
2920#if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS)
2921DEFINE_BPF_ITER_FUNC(tcp, struct bpf_iter_meta *meta,
2922 struct sock_common *sk_common, uid_t uid)
2923
2924static int bpf_iter_init_tcp(void *priv_data, struct bpf_iter_aux_info *aux)
2925{
2926 struct tcp_iter_state *st = priv_data;
2927 struct tcp_seq_afinfo *afinfo;
2928 int ret;
2929
2930 afinfo = kmalloc(sizeof(*afinfo), GFP_USER | __GFP_NOWARN);
2931 if (!afinfo)
2932 return -ENOMEM;
2933
2934 afinfo->family = AF_UNSPEC;
2935 st->bpf_seq_afinfo = afinfo;
2936 ret = bpf_iter_init_seq_net(priv_data, aux);
2937 if (ret)
2938 kfree(afinfo);
2939 return ret;
2940}
2941
2942static void bpf_iter_fini_tcp(void *priv_data)
2943{
2944 struct tcp_iter_state *st = priv_data;
2945
2946 kfree(st->bpf_seq_afinfo);
2947 bpf_iter_fini_seq_net(priv_data);
2948}
2949
2950static const struct bpf_iter_seq_info tcp_seq_info = {
2951 .seq_ops = &bpf_iter_tcp_seq_ops,
2952 .init_seq_private = bpf_iter_init_tcp,
2953 .fini_seq_private = bpf_iter_fini_tcp,
2954 .seq_priv_size = sizeof(struct tcp_iter_state),
2955};
2956
2957static struct bpf_iter_reg tcp_reg_info = {
2958 .target = "tcp",
2959 .ctx_arg_info_size = 1,
2960 .ctx_arg_info = {
2961 { offsetof(struct bpf_iter__tcp, sk_common),
2962 PTR_TO_BTF_ID_OR_NULL },
2963 },
2964 .seq_info = &tcp_seq_info,
2965};
2966
2967static void __init bpf_iter_register(void)
2968{
2969 tcp_reg_info.ctx_arg_info[0].btf_id = btf_sock_ids[BTF_SOCK_TYPE_SOCK_COMMON];
2970 if (bpf_iter_reg_target(&tcp_reg_info))
2971 pr_warn("Warning: could not register bpf iterator tcp\n");
2972}
2973
2974#endif
2975
2976void __init tcp_v4_init(void)
2977{
2978 if (register_pernet_subsys(&tcp_sk_ops))
2979 panic("Failed to create the TCP control socket.\n");
2980
2981#if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS)
2982 bpf_iter_register();
2983#endif
2984}
1// 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 /* inet_twsk_hashdance() sets sk_refcnt after putting twsk
158 * and releasing the bucket lock.
159 */
160 if (unlikely(!refcount_inc_not_zero(&sktw->sk_refcnt)))
161 return 0;
162
163 /* In case of repair and re-using TIME-WAIT sockets we still
164 * want to be sure that it is safe as above but honor the
165 * sequence numbers and time stamps set as part of the repair
166 * process.
167 *
168 * Without this check re-using a TIME-WAIT socket with TCP
169 * repair would accumulate a -1 on the repair assigned
170 * sequence number. The first time it is reused the sequence
171 * is -1, the second time -2, etc. This fixes that issue
172 * without appearing to create any others.
173 */
174 if (likely(!tp->repair)) {
175 u32 seq = tcptw->tw_snd_nxt + 65535 + 2;
176
177 if (!seq)
178 seq = 1;
179 WRITE_ONCE(tp->write_seq, seq);
180 tp->rx_opt.ts_recent = tcptw->tw_ts_recent;
181 tp->rx_opt.ts_recent_stamp = tcptw->tw_ts_recent_stamp;
182 }
183
184 return 1;
185 }
186
187 return 0;
188}
189EXPORT_SYMBOL_GPL(tcp_twsk_unique);
190
191static int tcp_v4_pre_connect(struct sock *sk, struct sockaddr *uaddr,
192 int addr_len)
193{
194 /* This check is replicated from tcp_v4_connect() and intended to
195 * prevent BPF program called below from accessing bytes that are out
196 * of the bound specified by user in addr_len.
197 */
198 if (addr_len < sizeof(struct sockaddr_in))
199 return -EINVAL;
200
201 sock_owned_by_me(sk);
202
203 return BPF_CGROUP_RUN_PROG_INET4_CONNECT(sk, uaddr, &addr_len);
204}
205
206/* This will initiate an outgoing connection. */
207int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
208{
209 struct sockaddr_in *usin = (struct sockaddr_in *)uaddr;
210 struct inet_timewait_death_row *tcp_death_row;
211 struct inet_sock *inet = inet_sk(sk);
212 struct tcp_sock *tp = tcp_sk(sk);
213 struct ip_options_rcu *inet_opt;
214 struct net *net = sock_net(sk);
215 __be16 orig_sport, orig_dport;
216 __be32 daddr, nexthop;
217 struct flowi4 *fl4;
218 struct rtable *rt;
219 int err;
220
221 if (addr_len < sizeof(struct sockaddr_in))
222 return -EINVAL;
223
224 if (usin->sin_family != AF_INET)
225 return -EAFNOSUPPORT;
226
227 nexthop = daddr = usin->sin_addr.s_addr;
228 inet_opt = rcu_dereference_protected(inet->inet_opt,
229 lockdep_sock_is_held(sk));
230 if (inet_opt && inet_opt->opt.srr) {
231 if (!daddr)
232 return -EINVAL;
233 nexthop = inet_opt->opt.faddr;
234 }
235
236 orig_sport = inet->inet_sport;
237 orig_dport = usin->sin_port;
238 fl4 = &inet->cork.fl.u.ip4;
239 rt = ip_route_connect(fl4, nexthop, inet->inet_saddr,
240 sk->sk_bound_dev_if, IPPROTO_TCP, orig_sport,
241 orig_dport, sk);
242 if (IS_ERR(rt)) {
243 err = PTR_ERR(rt);
244 if (err == -ENETUNREACH)
245 IP_INC_STATS(net, IPSTATS_MIB_OUTNOROUTES);
246 return err;
247 }
248
249 if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) {
250 ip_rt_put(rt);
251 return -ENETUNREACH;
252 }
253
254 if (!inet_opt || !inet_opt->opt.srr)
255 daddr = fl4->daddr;
256
257 tcp_death_row = &sock_net(sk)->ipv4.tcp_death_row;
258
259 if (!inet->inet_saddr) {
260 err = inet_bhash2_update_saddr(sk, &fl4->saddr, AF_INET);
261 if (err) {
262 ip_rt_put(rt);
263 return err;
264 }
265 } else {
266 sk_rcv_saddr_set(sk, inet->inet_saddr);
267 }
268
269 if (tp->rx_opt.ts_recent_stamp && inet->inet_daddr != daddr) {
270 /* Reset inherited state */
271 tp->rx_opt.ts_recent = 0;
272 tp->rx_opt.ts_recent_stamp = 0;
273 if (likely(!tp->repair))
274 WRITE_ONCE(tp->write_seq, 0);
275 }
276
277 inet->inet_dport = usin->sin_port;
278 sk_daddr_set(sk, daddr);
279
280 inet_csk(sk)->icsk_ext_hdr_len = 0;
281 if (inet_opt)
282 inet_csk(sk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
283
284 tp->rx_opt.mss_clamp = TCP_MSS_DEFAULT;
285
286 /* Socket identity is still unknown (sport may be zero).
287 * However we set state to SYN-SENT and not releasing socket
288 * lock select source port, enter ourselves into the hash tables and
289 * complete initialization after this.
290 */
291 tcp_set_state(sk, TCP_SYN_SENT);
292 err = inet_hash_connect(tcp_death_row, sk);
293 if (err)
294 goto failure;
295
296 sk_set_txhash(sk);
297
298 rt = ip_route_newports(fl4, rt, orig_sport, orig_dport,
299 inet->inet_sport, inet->inet_dport, sk);
300 if (IS_ERR(rt)) {
301 err = PTR_ERR(rt);
302 rt = NULL;
303 goto failure;
304 }
305 tp->tcp_usec_ts = dst_tcp_usec_ts(&rt->dst);
306 /* OK, now commit destination to socket. */
307 sk->sk_gso_type = SKB_GSO_TCPV4;
308 sk_setup_caps(sk, &rt->dst);
309 rt = NULL;
310
311 if (likely(!tp->repair)) {
312 if (!tp->write_seq)
313 WRITE_ONCE(tp->write_seq,
314 secure_tcp_seq(inet->inet_saddr,
315 inet->inet_daddr,
316 inet->inet_sport,
317 usin->sin_port));
318 WRITE_ONCE(tp->tsoffset,
319 secure_tcp_ts_off(net, inet->inet_saddr,
320 inet->inet_daddr));
321 }
322
323 atomic_set(&inet->inet_id, get_random_u16());
324
325 if (tcp_fastopen_defer_connect(sk, &err))
326 return err;
327 if (err)
328 goto failure;
329
330 err = tcp_connect(sk);
331
332 if (err)
333 goto failure;
334
335 return 0;
336
337failure:
338 /*
339 * This unhashes the socket and releases the local port,
340 * if necessary.
341 */
342 tcp_set_state(sk, TCP_CLOSE);
343 inet_bhash2_reset_saddr(sk);
344 ip_rt_put(rt);
345 sk->sk_route_caps = 0;
346 inet->inet_dport = 0;
347 return err;
348}
349EXPORT_SYMBOL(tcp_v4_connect);
350
351/*
352 * This routine reacts to ICMP_FRAG_NEEDED mtu indications as defined in RFC1191.
353 * It can be called through tcp_release_cb() if socket was owned by user
354 * at the time tcp_v4_err() was called to handle ICMP message.
355 */
356void tcp_v4_mtu_reduced(struct sock *sk)
357{
358 struct inet_sock *inet = inet_sk(sk);
359 struct dst_entry *dst;
360 u32 mtu;
361
362 if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE))
363 return;
364 mtu = READ_ONCE(tcp_sk(sk)->mtu_info);
365 dst = inet_csk_update_pmtu(sk, mtu);
366 if (!dst)
367 return;
368
369 /* Something is about to be wrong... Remember soft error
370 * for the case, if this connection will not able to recover.
371 */
372 if (mtu < dst_mtu(dst) && ip_dont_fragment(sk, dst))
373 WRITE_ONCE(sk->sk_err_soft, EMSGSIZE);
374
375 mtu = dst_mtu(dst);
376
377 if (inet->pmtudisc != IP_PMTUDISC_DONT &&
378 ip_sk_accept_pmtu(sk) &&
379 inet_csk(sk)->icsk_pmtu_cookie > mtu) {
380 tcp_sync_mss(sk, mtu);
381
382 /* Resend the TCP packet because it's
383 * clear that the old packet has been
384 * dropped. This is the new "fast" path mtu
385 * discovery.
386 */
387 tcp_simple_retransmit(sk);
388 } /* else let the usual retransmit timer handle it */
389}
390EXPORT_SYMBOL(tcp_v4_mtu_reduced);
391
392static void do_redirect(struct sk_buff *skb, struct sock *sk)
393{
394 struct dst_entry *dst = __sk_dst_check(sk, 0);
395
396 if (dst)
397 dst->ops->redirect(dst, sk, skb);
398}
399
400
401/* handle ICMP messages on TCP_NEW_SYN_RECV request sockets */
402void tcp_req_err(struct sock *sk, u32 seq, bool abort)
403{
404 struct request_sock *req = inet_reqsk(sk);
405 struct net *net = sock_net(sk);
406
407 /* ICMPs are not backlogged, hence we cannot get
408 * an established socket here.
409 */
410 if (seq != tcp_rsk(req)->snt_isn) {
411 __NET_INC_STATS(net, LINUX_MIB_OUTOFWINDOWICMPS);
412 } else if (abort) {
413 /*
414 * Still in SYN_RECV, just remove it silently.
415 * There is no good way to pass the error to the newly
416 * created socket, and POSIX does not want network
417 * errors returned from accept().
418 */
419 inet_csk_reqsk_queue_drop(req->rsk_listener, req);
420 tcp_listendrop(req->rsk_listener);
421 }
422 reqsk_put(req);
423}
424EXPORT_SYMBOL(tcp_req_err);
425
426/* TCP-LD (RFC 6069) logic */
427void tcp_ld_RTO_revert(struct sock *sk, u32 seq)
428{
429 struct inet_connection_sock *icsk = inet_csk(sk);
430 struct tcp_sock *tp = tcp_sk(sk);
431 struct sk_buff *skb;
432 s32 remaining;
433 u32 delta_us;
434
435 if (sock_owned_by_user(sk))
436 return;
437
438 if (seq != tp->snd_una || !icsk->icsk_retransmits ||
439 !icsk->icsk_backoff)
440 return;
441
442 skb = tcp_rtx_queue_head(sk);
443 if (WARN_ON_ONCE(!skb))
444 return;
445
446 icsk->icsk_backoff--;
447 icsk->icsk_rto = tp->srtt_us ? __tcp_set_rto(tp) : TCP_TIMEOUT_INIT;
448 icsk->icsk_rto = inet_csk_rto_backoff(icsk, TCP_RTO_MAX);
449
450 tcp_mstamp_refresh(tp);
451 delta_us = (u32)(tp->tcp_mstamp - tcp_skb_timestamp_us(skb));
452 remaining = icsk->icsk_rto - usecs_to_jiffies(delta_us);
453
454 if (remaining > 0) {
455 inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
456 remaining, TCP_RTO_MAX);
457 } else {
458 /* RTO revert clocked out retransmission.
459 * Will retransmit now.
460 */
461 tcp_retransmit_timer(sk);
462 }
463}
464EXPORT_SYMBOL(tcp_ld_RTO_revert);
465
466/*
467 * This routine is called by the ICMP module when it gets some
468 * sort of error condition. If err < 0 then the socket should
469 * be closed and the error returned to the user. If err > 0
470 * it's just the icmp type << 8 | icmp code. After adjustment
471 * header points to the first 8 bytes of the tcp header. We need
472 * to find the appropriate port.
473 *
474 * The locking strategy used here is very "optimistic". When
475 * someone else accesses the socket the ICMP is just dropped
476 * and for some paths there is no check at all.
477 * A more general error queue to queue errors for later handling
478 * is probably better.
479 *
480 */
481
482int tcp_v4_err(struct sk_buff *skb, u32 info)
483{
484 const struct iphdr *iph = (const struct iphdr *)skb->data;
485 struct tcphdr *th = (struct tcphdr *)(skb->data + (iph->ihl << 2));
486 struct tcp_sock *tp;
487 const int type = icmp_hdr(skb)->type;
488 const int code = icmp_hdr(skb)->code;
489 struct sock *sk;
490 struct request_sock *fastopen;
491 u32 seq, snd_una;
492 int err;
493 struct net *net = dev_net(skb->dev);
494
495 sk = __inet_lookup_established(net, net->ipv4.tcp_death_row.hashinfo,
496 iph->daddr, th->dest, iph->saddr,
497 ntohs(th->source), inet_iif(skb), 0);
498 if (!sk) {
499 __ICMP_INC_STATS(net, ICMP_MIB_INERRORS);
500 return -ENOENT;
501 }
502 if (sk->sk_state == TCP_TIME_WAIT) {
503 /* To increase the counter of ignored icmps for TCP-AO */
504 tcp_ao_ignore_icmp(sk, AF_INET, type, code);
505 inet_twsk_put(inet_twsk(sk));
506 return 0;
507 }
508 seq = ntohl(th->seq);
509 if (sk->sk_state == TCP_NEW_SYN_RECV) {
510 tcp_req_err(sk, seq, type == ICMP_PARAMETERPROB ||
511 type == ICMP_TIME_EXCEEDED ||
512 (type == ICMP_DEST_UNREACH &&
513 (code == ICMP_NET_UNREACH ||
514 code == ICMP_HOST_UNREACH)));
515 return 0;
516 }
517
518 if (tcp_ao_ignore_icmp(sk, AF_INET, type, code)) {
519 sock_put(sk);
520 return 0;
521 }
522
523 bh_lock_sock(sk);
524 /* If too many ICMPs get dropped on busy
525 * servers this needs to be solved differently.
526 * We do take care of PMTU discovery (RFC1191) special case :
527 * we can receive locally generated ICMP messages while socket is held.
528 */
529 if (sock_owned_by_user(sk)) {
530 if (!(type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED))
531 __NET_INC_STATS(net, LINUX_MIB_LOCKDROPPEDICMPS);
532 }
533 if (sk->sk_state == TCP_CLOSE)
534 goto out;
535
536 if (static_branch_unlikely(&ip4_min_ttl)) {
537 /* min_ttl can be changed concurrently from do_ip_setsockopt() */
538 if (unlikely(iph->ttl < READ_ONCE(inet_sk(sk)->min_ttl))) {
539 __NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP);
540 goto out;
541 }
542 }
543
544 tp = tcp_sk(sk);
545 /* XXX (TFO) - tp->snd_una should be ISN (tcp_create_openreq_child() */
546 fastopen = rcu_dereference(tp->fastopen_rsk);
547 snd_una = fastopen ? tcp_rsk(fastopen)->snt_isn : tp->snd_una;
548 if (sk->sk_state != TCP_LISTEN &&
549 !between(seq, snd_una, tp->snd_nxt)) {
550 __NET_INC_STATS(net, LINUX_MIB_OUTOFWINDOWICMPS);
551 goto out;
552 }
553
554 switch (type) {
555 case ICMP_REDIRECT:
556 if (!sock_owned_by_user(sk))
557 do_redirect(skb, sk);
558 goto out;
559 case ICMP_SOURCE_QUENCH:
560 /* Just silently ignore these. */
561 goto out;
562 case ICMP_PARAMETERPROB:
563 err = EPROTO;
564 break;
565 case ICMP_DEST_UNREACH:
566 if (code > NR_ICMP_UNREACH)
567 goto out;
568
569 if (code == ICMP_FRAG_NEEDED) { /* PMTU discovery (RFC1191) */
570 /* We are not interested in TCP_LISTEN and open_requests
571 * (SYN-ACKs send out by Linux are always <576bytes so
572 * they should go through unfragmented).
573 */
574 if (sk->sk_state == TCP_LISTEN)
575 goto out;
576
577 WRITE_ONCE(tp->mtu_info, info);
578 if (!sock_owned_by_user(sk)) {
579 tcp_v4_mtu_reduced(sk);
580 } else {
581 if (!test_and_set_bit(TCP_MTU_REDUCED_DEFERRED, &sk->sk_tsq_flags))
582 sock_hold(sk);
583 }
584 goto out;
585 }
586
587 err = icmp_err_convert[code].errno;
588 /* check if this ICMP message allows revert of backoff.
589 * (see RFC 6069)
590 */
591 if (!fastopen &&
592 (code == ICMP_NET_UNREACH || code == ICMP_HOST_UNREACH))
593 tcp_ld_RTO_revert(sk, seq);
594 break;
595 case ICMP_TIME_EXCEEDED:
596 err = EHOSTUNREACH;
597 break;
598 default:
599 goto out;
600 }
601
602 switch (sk->sk_state) {
603 case TCP_SYN_SENT:
604 case TCP_SYN_RECV:
605 /* Only in fast or simultaneous open. If a fast open socket is
606 * already accepted it is treated as a connected one below.
607 */
608 if (fastopen && !fastopen->sk)
609 break;
610
611 ip_icmp_error(sk, skb, err, th->dest, info, (u8 *)th);
612
613 if (!sock_owned_by_user(sk)) {
614 WRITE_ONCE(sk->sk_err, err);
615
616 sk_error_report(sk);
617
618 tcp_done(sk);
619 } else {
620 WRITE_ONCE(sk->sk_err_soft, err);
621 }
622 goto out;
623 }
624
625 /* If we've already connected we will keep trying
626 * until we time out, or the user gives up.
627 *
628 * rfc1122 4.2.3.9 allows to consider as hard errors
629 * only PROTO_UNREACH and PORT_UNREACH (well, FRAG_FAILED too,
630 * but it is obsoleted by pmtu discovery).
631 *
632 * Note, that in modern internet, where routing is unreliable
633 * and in each dark corner broken firewalls sit, sending random
634 * errors ordered by their masters even this two messages finally lose
635 * their original sense (even Linux sends invalid PORT_UNREACHs)
636 *
637 * Now we are in compliance with RFCs.
638 * --ANK (980905)
639 */
640
641 if (!sock_owned_by_user(sk) &&
642 inet_test_bit(RECVERR, sk)) {
643 WRITE_ONCE(sk->sk_err, err);
644 sk_error_report(sk);
645 } else { /* Only an error on timeout */
646 WRITE_ONCE(sk->sk_err_soft, err);
647 }
648
649out:
650 bh_unlock_sock(sk);
651 sock_put(sk);
652 return 0;
653}
654
655void __tcp_v4_send_check(struct sk_buff *skb, __be32 saddr, __be32 daddr)
656{
657 struct tcphdr *th = tcp_hdr(skb);
658
659 th->check = ~tcp_v4_check(skb->len, saddr, daddr, 0);
660 skb->csum_start = skb_transport_header(skb) - skb->head;
661 skb->csum_offset = offsetof(struct tcphdr, check);
662}
663
664/* This routine computes an IPv4 TCP checksum. */
665void tcp_v4_send_check(struct sock *sk, struct sk_buff *skb)
666{
667 const struct inet_sock *inet = inet_sk(sk);
668
669 __tcp_v4_send_check(skb, inet->inet_saddr, inet->inet_daddr);
670}
671EXPORT_SYMBOL(tcp_v4_send_check);
672
673#define REPLY_OPTIONS_LEN (MAX_TCP_OPTION_SPACE / sizeof(__be32))
674
675static bool tcp_v4_ao_sign_reset(const struct sock *sk, struct sk_buff *skb,
676 const struct tcp_ao_hdr *aoh,
677 struct ip_reply_arg *arg, struct tcphdr *reply,
678 __be32 reply_options[REPLY_OPTIONS_LEN])
679{
680#ifdef CONFIG_TCP_AO
681 int sdif = tcp_v4_sdif(skb);
682 int dif = inet_iif(skb);
683 int l3index = sdif ? dif : 0;
684 bool allocated_traffic_key;
685 struct tcp_ao_key *key;
686 char *traffic_key;
687 bool drop = true;
688 u32 ao_sne = 0;
689 u8 keyid;
690
691 rcu_read_lock();
692 if (tcp_ao_prepare_reset(sk, skb, aoh, l3index, ntohl(reply->seq),
693 &key, &traffic_key, &allocated_traffic_key,
694 &keyid, &ao_sne))
695 goto out;
696
697 reply_options[0] = htonl((TCPOPT_AO << 24) | (tcp_ao_len(key) << 16) |
698 (aoh->rnext_keyid << 8) | keyid);
699 arg->iov[0].iov_len += tcp_ao_len_aligned(key);
700 reply->doff = arg->iov[0].iov_len / 4;
701
702 if (tcp_ao_hash_hdr(AF_INET, (char *)&reply_options[1],
703 key, traffic_key,
704 (union tcp_ao_addr *)&ip_hdr(skb)->saddr,
705 (union tcp_ao_addr *)&ip_hdr(skb)->daddr,
706 reply, ao_sne))
707 goto out;
708 drop = false;
709out:
710 rcu_read_unlock();
711 if (allocated_traffic_key)
712 kfree(traffic_key);
713 return drop;
714#else
715 return true;
716#endif
717}
718
719/*
720 * This routine will send an RST to the other tcp.
721 *
722 * Someone asks: why I NEVER use socket parameters (TOS, TTL etc.)
723 * for reset.
724 * Answer: if a packet caused RST, it is not for a socket
725 * existing in our system, if it is matched to a socket,
726 * it is just duplicate segment or bug in other side's TCP.
727 * So that we build reply only basing on parameters
728 * arrived with segment.
729 * Exception: precedence violation. We do not implement it in any case.
730 */
731
732static void tcp_v4_send_reset(const struct sock *sk, struct sk_buff *skb)
733{
734 const struct tcphdr *th = tcp_hdr(skb);
735 struct {
736 struct tcphdr th;
737 __be32 opt[REPLY_OPTIONS_LEN];
738 } rep;
739 const __u8 *md5_hash_location = NULL;
740 const struct tcp_ao_hdr *aoh;
741 struct ip_reply_arg arg;
742#ifdef CONFIG_TCP_MD5SIG
743 struct tcp_md5sig_key *key = NULL;
744 unsigned char newhash[16];
745 struct sock *sk1 = NULL;
746 int genhash;
747#endif
748 u64 transmit_time = 0;
749 struct sock *ctl_sk;
750 struct net *net;
751 u32 txhash = 0;
752
753 /* Never send a reset in response to a reset. */
754 if (th->rst)
755 return;
756
757 /* If sk not NULL, it means we did a successful lookup and incoming
758 * route had to be correct. prequeue might have dropped our dst.
759 */
760 if (!sk && skb_rtable(skb)->rt_type != RTN_LOCAL)
761 return;
762
763 /* Swap the send and the receive. */
764 memset(&rep, 0, sizeof(rep));
765 rep.th.dest = th->source;
766 rep.th.source = th->dest;
767 rep.th.doff = sizeof(struct tcphdr) / 4;
768 rep.th.rst = 1;
769
770 if (th->ack) {
771 rep.th.seq = th->ack_seq;
772 } else {
773 rep.th.ack = 1;
774 rep.th.ack_seq = htonl(ntohl(th->seq) + th->syn + th->fin +
775 skb->len - (th->doff << 2));
776 }
777
778 memset(&arg, 0, sizeof(arg));
779 arg.iov[0].iov_base = (unsigned char *)&rep;
780 arg.iov[0].iov_len = sizeof(rep.th);
781
782 net = sk ? sock_net(sk) : dev_net(skb_dst(skb)->dev);
783
784 /* Invalid TCP option size or twice included auth */
785 if (tcp_parse_auth_options(tcp_hdr(skb), &md5_hash_location, &aoh))
786 return;
787
788 if (aoh && tcp_v4_ao_sign_reset(sk, skb, aoh, &arg, &rep.th, rep.opt))
789 return;
790
791#ifdef CONFIG_TCP_MD5SIG
792 rcu_read_lock();
793 if (sk && sk_fullsock(sk)) {
794 const union tcp_md5_addr *addr;
795 int l3index;
796
797 /* sdif set, means packet ingressed via a device
798 * in an L3 domain and inet_iif is set to it.
799 */
800 l3index = tcp_v4_sdif(skb) ? inet_iif(skb) : 0;
801 addr = (union tcp_md5_addr *)&ip_hdr(skb)->saddr;
802 key = tcp_md5_do_lookup(sk, l3index, addr, AF_INET);
803 } else if (md5_hash_location) {
804 const union tcp_md5_addr *addr;
805 int sdif = tcp_v4_sdif(skb);
806 int dif = inet_iif(skb);
807 int l3index;
808
809 /*
810 * active side is lost. Try to find listening socket through
811 * source port, and then find md5 key through listening socket.
812 * we are not loose security here:
813 * Incoming packet is checked with md5 hash with finding key,
814 * no RST generated if md5 hash doesn't match.
815 */
816 sk1 = __inet_lookup_listener(net, net->ipv4.tcp_death_row.hashinfo,
817 NULL, 0, ip_hdr(skb)->saddr,
818 th->source, ip_hdr(skb)->daddr,
819 ntohs(th->source), dif, sdif);
820 /* don't send rst if it can't find key */
821 if (!sk1)
822 goto out;
823
824 /* sdif set, means packet ingressed via a device
825 * in an L3 domain and dif is set to it.
826 */
827 l3index = sdif ? dif : 0;
828 addr = (union tcp_md5_addr *)&ip_hdr(skb)->saddr;
829 key = tcp_md5_do_lookup(sk1, l3index, addr, AF_INET);
830 if (!key)
831 goto out;
832
833
834 genhash = tcp_v4_md5_hash_skb(newhash, key, NULL, skb);
835 if (genhash || memcmp(md5_hash_location, newhash, 16) != 0)
836 goto out;
837
838 }
839
840 if (key) {
841 rep.opt[0] = htonl((TCPOPT_NOP << 24) |
842 (TCPOPT_NOP << 16) |
843 (TCPOPT_MD5SIG << 8) |
844 TCPOLEN_MD5SIG);
845 /* Update length and the length the header thinks exists */
846 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED;
847 rep.th.doff = arg.iov[0].iov_len / 4;
848
849 tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[1],
850 key, ip_hdr(skb)->saddr,
851 ip_hdr(skb)->daddr, &rep.th);
852 }
853#endif
854 /* Can't co-exist with TCPMD5, hence check rep.opt[0] */
855 if (rep.opt[0] == 0) {
856 __be32 mrst = mptcp_reset_option(skb);
857
858 if (mrst) {
859 rep.opt[0] = mrst;
860 arg.iov[0].iov_len += sizeof(mrst);
861 rep.th.doff = arg.iov[0].iov_len / 4;
862 }
863 }
864
865 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
866 ip_hdr(skb)->saddr, /* XXX */
867 arg.iov[0].iov_len, IPPROTO_TCP, 0);
868 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
869 arg.flags = (sk && inet_sk_transparent(sk)) ? IP_REPLY_ARG_NOSRCCHECK : 0;
870
871 /* When socket is gone, all binding information is lost.
872 * routing might fail in this case. No choice here, if we choose to force
873 * input interface, we will misroute in case of asymmetric route.
874 */
875 if (sk) {
876 arg.bound_dev_if = sk->sk_bound_dev_if;
877 if (sk_fullsock(sk))
878 trace_tcp_send_reset(sk, skb);
879 }
880
881 BUILD_BUG_ON(offsetof(struct sock, sk_bound_dev_if) !=
882 offsetof(struct inet_timewait_sock, tw_bound_dev_if));
883
884 arg.tos = ip_hdr(skb)->tos;
885 arg.uid = sock_net_uid(net, sk && sk_fullsock(sk) ? sk : NULL);
886 local_bh_disable();
887 ctl_sk = this_cpu_read(ipv4_tcp_sk);
888 sock_net_set(ctl_sk, net);
889 if (sk) {
890 ctl_sk->sk_mark = (sk->sk_state == TCP_TIME_WAIT) ?
891 inet_twsk(sk)->tw_mark : sk->sk_mark;
892 ctl_sk->sk_priority = (sk->sk_state == TCP_TIME_WAIT) ?
893 inet_twsk(sk)->tw_priority : READ_ONCE(sk->sk_priority);
894 transmit_time = tcp_transmit_time(sk);
895 xfrm_sk_clone_policy(ctl_sk, sk);
896 txhash = (sk->sk_state == TCP_TIME_WAIT) ?
897 inet_twsk(sk)->tw_txhash : sk->sk_txhash;
898 } else {
899 ctl_sk->sk_mark = 0;
900 ctl_sk->sk_priority = 0;
901 }
902 ip_send_unicast_reply(ctl_sk,
903 skb, &TCP_SKB_CB(skb)->header.h4.opt,
904 ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
905 &arg, arg.iov[0].iov_len,
906 transmit_time, txhash);
907
908 xfrm_sk_free_policy(ctl_sk);
909 sock_net_set(ctl_sk, &init_net);
910 __TCP_INC_STATS(net, TCP_MIB_OUTSEGS);
911 __TCP_INC_STATS(net, TCP_MIB_OUTRSTS);
912 local_bh_enable();
913
914#ifdef CONFIG_TCP_MD5SIG
915out:
916 rcu_read_unlock();
917#endif
918}
919
920/* The code following below sending ACKs in SYN-RECV and TIME-WAIT states
921 outside socket context is ugly, certainly. What can I do?
922 */
923
924static void tcp_v4_send_ack(const struct sock *sk,
925 struct sk_buff *skb, u32 seq, u32 ack,
926 u32 win, u32 tsval, u32 tsecr, int oif,
927 struct tcp_key *key,
928 int reply_flags, u8 tos, u32 txhash)
929{
930 const struct tcphdr *th = tcp_hdr(skb);
931 struct {
932 struct tcphdr th;
933 __be32 opt[(MAX_TCP_OPTION_SPACE >> 2)];
934 } rep;
935 struct net *net = sock_net(sk);
936 struct ip_reply_arg arg;
937 struct sock *ctl_sk;
938 u64 transmit_time;
939
940 memset(&rep.th, 0, sizeof(struct tcphdr));
941 memset(&arg, 0, sizeof(arg));
942
943 arg.iov[0].iov_base = (unsigned char *)&rep;
944 arg.iov[0].iov_len = sizeof(rep.th);
945 if (tsecr) {
946 rep.opt[0] = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
947 (TCPOPT_TIMESTAMP << 8) |
948 TCPOLEN_TIMESTAMP);
949 rep.opt[1] = htonl(tsval);
950 rep.opt[2] = htonl(tsecr);
951 arg.iov[0].iov_len += TCPOLEN_TSTAMP_ALIGNED;
952 }
953
954 /* Swap the send and the receive. */
955 rep.th.dest = th->source;
956 rep.th.source = th->dest;
957 rep.th.doff = arg.iov[0].iov_len / 4;
958 rep.th.seq = htonl(seq);
959 rep.th.ack_seq = htonl(ack);
960 rep.th.ack = 1;
961 rep.th.window = htons(win);
962
963#ifdef CONFIG_TCP_MD5SIG
964 if (tcp_key_is_md5(key)) {
965 int offset = (tsecr) ? 3 : 0;
966
967 rep.opt[offset++] = htonl((TCPOPT_NOP << 24) |
968 (TCPOPT_NOP << 16) |
969 (TCPOPT_MD5SIG << 8) |
970 TCPOLEN_MD5SIG);
971 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED;
972 rep.th.doff = arg.iov[0].iov_len/4;
973
974 tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[offset],
975 key->md5_key, ip_hdr(skb)->saddr,
976 ip_hdr(skb)->daddr, &rep.th);
977 }
978#endif
979#ifdef CONFIG_TCP_AO
980 if (tcp_key_is_ao(key)) {
981 int offset = (tsecr) ? 3 : 0;
982
983 rep.opt[offset++] = htonl((TCPOPT_AO << 24) |
984 (tcp_ao_len(key->ao_key) << 16) |
985 (key->ao_key->sndid << 8) |
986 key->rcv_next);
987 arg.iov[0].iov_len += tcp_ao_len_aligned(key->ao_key);
988 rep.th.doff = arg.iov[0].iov_len / 4;
989
990 tcp_ao_hash_hdr(AF_INET, (char *)&rep.opt[offset],
991 key->ao_key, key->traffic_key,
992 (union tcp_ao_addr *)&ip_hdr(skb)->saddr,
993 (union tcp_ao_addr *)&ip_hdr(skb)->daddr,
994 &rep.th, key->sne);
995 }
996#endif
997 arg.flags = reply_flags;
998 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
999 ip_hdr(skb)->saddr, /* XXX */
1000 arg.iov[0].iov_len, IPPROTO_TCP, 0);
1001 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
1002 if (oif)
1003 arg.bound_dev_if = oif;
1004 arg.tos = tos;
1005 arg.uid = sock_net_uid(net, sk_fullsock(sk) ? sk : NULL);
1006 local_bh_disable();
1007 ctl_sk = this_cpu_read(ipv4_tcp_sk);
1008 sock_net_set(ctl_sk, net);
1009 ctl_sk->sk_mark = (sk->sk_state == TCP_TIME_WAIT) ?
1010 inet_twsk(sk)->tw_mark : READ_ONCE(sk->sk_mark);
1011 ctl_sk->sk_priority = (sk->sk_state == TCP_TIME_WAIT) ?
1012 inet_twsk(sk)->tw_priority : READ_ONCE(sk->sk_priority);
1013 transmit_time = tcp_transmit_time(sk);
1014 ip_send_unicast_reply(ctl_sk,
1015 skb, &TCP_SKB_CB(skb)->header.h4.opt,
1016 ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
1017 &arg, arg.iov[0].iov_len,
1018 transmit_time, txhash);
1019
1020 sock_net_set(ctl_sk, &init_net);
1021 __TCP_INC_STATS(net, TCP_MIB_OUTSEGS);
1022 local_bh_enable();
1023}
1024
1025static void tcp_v4_timewait_ack(struct sock *sk, struct sk_buff *skb)
1026{
1027 struct inet_timewait_sock *tw = inet_twsk(sk);
1028 struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
1029 struct tcp_key key = {};
1030#ifdef CONFIG_TCP_AO
1031 struct tcp_ao_info *ao_info;
1032
1033 if (static_branch_unlikely(&tcp_ao_needed.key)) {
1034 /* FIXME: the segment to-be-acked is not verified yet */
1035 ao_info = rcu_dereference(tcptw->ao_info);
1036 if (ao_info) {
1037 const struct tcp_ao_hdr *aoh;
1038
1039 if (tcp_parse_auth_options(tcp_hdr(skb), NULL, &aoh)) {
1040 inet_twsk_put(tw);
1041 return;
1042 }
1043
1044 if (aoh)
1045 key.ao_key = tcp_ao_established_key(ao_info, aoh->rnext_keyid, -1);
1046 }
1047 }
1048 if (key.ao_key) {
1049 struct tcp_ao_key *rnext_key;
1050
1051 key.traffic_key = snd_other_key(key.ao_key);
1052 key.sne = READ_ONCE(ao_info->snd_sne);
1053 rnext_key = READ_ONCE(ao_info->rnext_key);
1054 key.rcv_next = rnext_key->rcvid;
1055 key.type = TCP_KEY_AO;
1056#else
1057 if (0) {
1058#endif
1059#ifdef CONFIG_TCP_MD5SIG
1060 } else if (static_branch_unlikely(&tcp_md5_needed.key)) {
1061 key.md5_key = tcp_twsk_md5_key(tcptw);
1062 if (key.md5_key)
1063 key.type = TCP_KEY_MD5;
1064#endif
1065 }
1066
1067 tcp_v4_send_ack(sk, skb,
1068 tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
1069 tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
1070 tcp_tw_tsval(tcptw),
1071 tcptw->tw_ts_recent,
1072 tw->tw_bound_dev_if, &key,
1073 tw->tw_transparent ? IP_REPLY_ARG_NOSRCCHECK : 0,
1074 tw->tw_tos,
1075 tw->tw_txhash);
1076
1077 inet_twsk_put(tw);
1078}
1079
1080static void tcp_v4_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb,
1081 struct request_sock *req)
1082{
1083 struct tcp_key key = {};
1084
1085 /* sk->sk_state == TCP_LISTEN -> for regular TCP_SYN_RECV
1086 * sk->sk_state == TCP_SYN_RECV -> for Fast Open.
1087 */
1088 u32 seq = (sk->sk_state == TCP_LISTEN) ? tcp_rsk(req)->snt_isn + 1 :
1089 tcp_sk(sk)->snd_nxt;
1090
1091#ifdef CONFIG_TCP_AO
1092 if (static_branch_unlikely(&tcp_ao_needed.key) &&
1093 tcp_rsk_used_ao(req)) {
1094 const union tcp_md5_addr *addr;
1095 const struct tcp_ao_hdr *aoh;
1096 int l3index;
1097
1098 /* Invalid TCP option size or twice included auth */
1099 if (tcp_parse_auth_options(tcp_hdr(skb), NULL, &aoh))
1100 return;
1101 if (!aoh)
1102 return;
1103
1104 addr = (union tcp_md5_addr *)&ip_hdr(skb)->saddr;
1105 l3index = tcp_v4_sdif(skb) ? inet_iif(skb) : 0;
1106 key.ao_key = tcp_ao_do_lookup(sk, l3index, addr, AF_INET,
1107 aoh->rnext_keyid, -1);
1108 if (unlikely(!key.ao_key)) {
1109 /* Send ACK with any matching MKT for the peer */
1110 key.ao_key = tcp_ao_do_lookup(sk, l3index, addr, AF_INET, -1, -1);
1111 /* Matching key disappeared (user removed the key?)
1112 * let the handshake timeout.
1113 */
1114 if (!key.ao_key) {
1115 net_info_ratelimited("TCP-AO key for (%pI4, %d)->(%pI4, %d) suddenly disappeared, won't ACK new connection\n",
1116 addr,
1117 ntohs(tcp_hdr(skb)->source),
1118 &ip_hdr(skb)->daddr,
1119 ntohs(tcp_hdr(skb)->dest));
1120 return;
1121 }
1122 }
1123 key.traffic_key = kmalloc(tcp_ao_digest_size(key.ao_key), GFP_ATOMIC);
1124 if (!key.traffic_key)
1125 return;
1126
1127 key.type = TCP_KEY_AO;
1128 key.rcv_next = aoh->keyid;
1129 tcp_v4_ao_calc_key_rsk(key.ao_key, key.traffic_key, req);
1130#else
1131 if (0) {
1132#endif
1133#ifdef CONFIG_TCP_MD5SIG
1134 } else if (static_branch_unlikely(&tcp_md5_needed.key)) {
1135 const union tcp_md5_addr *addr;
1136 int l3index;
1137
1138 addr = (union tcp_md5_addr *)&ip_hdr(skb)->saddr;
1139 l3index = tcp_v4_sdif(skb) ? inet_iif(skb) : 0;
1140 key.md5_key = tcp_md5_do_lookup(sk, l3index, addr, AF_INET);
1141 if (key.md5_key)
1142 key.type = TCP_KEY_MD5;
1143#endif
1144 }
1145
1146 /* RFC 7323 2.3
1147 * The window field (SEG.WND) of every outgoing segment, with the
1148 * exception of <SYN> segments, MUST be right-shifted by
1149 * Rcv.Wind.Shift bits:
1150 */
1151 tcp_v4_send_ack(sk, skb, seq,
1152 tcp_rsk(req)->rcv_nxt,
1153 req->rsk_rcv_wnd >> inet_rsk(req)->rcv_wscale,
1154 tcp_rsk_tsval(tcp_rsk(req)),
1155 READ_ONCE(req->ts_recent),
1156 0, &key,
1157 inet_rsk(req)->no_srccheck ? IP_REPLY_ARG_NOSRCCHECK : 0,
1158 ip_hdr(skb)->tos,
1159 READ_ONCE(tcp_rsk(req)->txhash));
1160 if (tcp_key_is_ao(&key))
1161 kfree(key.traffic_key);
1162}
1163
1164/*
1165 * Send a SYN-ACK after having received a SYN.
1166 * This still operates on a request_sock only, not on a big
1167 * socket.
1168 */
1169static int tcp_v4_send_synack(const struct sock *sk, struct dst_entry *dst,
1170 struct flowi *fl,
1171 struct request_sock *req,
1172 struct tcp_fastopen_cookie *foc,
1173 enum tcp_synack_type synack_type,
1174 struct sk_buff *syn_skb)
1175{
1176 const struct inet_request_sock *ireq = inet_rsk(req);
1177 struct flowi4 fl4;
1178 int err = -1;
1179 struct sk_buff *skb;
1180 u8 tos;
1181
1182 /* First, grab a route. */
1183 if (!dst && (dst = inet_csk_route_req(sk, &fl4, req)) == NULL)
1184 return -1;
1185
1186 skb = tcp_make_synack(sk, dst, req, foc, synack_type, syn_skb);
1187
1188 if (skb) {
1189 __tcp_v4_send_check(skb, ireq->ir_loc_addr, ireq->ir_rmt_addr);
1190
1191 tos = READ_ONCE(inet_sk(sk)->tos);
1192
1193 if (READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_reflect_tos))
1194 tos = (tcp_rsk(req)->syn_tos & ~INET_ECN_MASK) |
1195 (tos & INET_ECN_MASK);
1196
1197 if (!INET_ECN_is_capable(tos) &&
1198 tcp_bpf_ca_needs_ecn((struct sock *)req))
1199 tos |= INET_ECN_ECT_0;
1200
1201 rcu_read_lock();
1202 err = ip_build_and_send_pkt(skb, sk, ireq->ir_loc_addr,
1203 ireq->ir_rmt_addr,
1204 rcu_dereference(ireq->ireq_opt),
1205 tos);
1206 rcu_read_unlock();
1207 err = net_xmit_eval(err);
1208 }
1209
1210 return err;
1211}
1212
1213/*
1214 * IPv4 request_sock destructor.
1215 */
1216static void tcp_v4_reqsk_destructor(struct request_sock *req)
1217{
1218 kfree(rcu_dereference_protected(inet_rsk(req)->ireq_opt, 1));
1219}
1220
1221#ifdef CONFIG_TCP_MD5SIG
1222/*
1223 * RFC2385 MD5 checksumming requires a mapping of
1224 * IP address->MD5 Key.
1225 * We need to maintain these in the sk structure.
1226 */
1227
1228DEFINE_STATIC_KEY_DEFERRED_FALSE(tcp_md5_needed, HZ);
1229EXPORT_SYMBOL(tcp_md5_needed);
1230
1231static bool better_md5_match(struct tcp_md5sig_key *old, struct tcp_md5sig_key *new)
1232{
1233 if (!old)
1234 return true;
1235
1236 /* l3index always overrides non-l3index */
1237 if (old->l3index && new->l3index == 0)
1238 return false;
1239 if (old->l3index == 0 && new->l3index)
1240 return true;
1241
1242 return old->prefixlen < new->prefixlen;
1243}
1244
1245/* Find the Key structure for an address. */
1246struct tcp_md5sig_key *__tcp_md5_do_lookup(const struct sock *sk, int l3index,
1247 const union tcp_md5_addr *addr,
1248 int family, bool any_l3index)
1249{
1250 const struct tcp_sock *tp = tcp_sk(sk);
1251 struct tcp_md5sig_key *key;
1252 const struct tcp_md5sig_info *md5sig;
1253 __be32 mask;
1254 struct tcp_md5sig_key *best_match = NULL;
1255 bool match;
1256
1257 /* caller either holds rcu_read_lock() or socket lock */
1258 md5sig = rcu_dereference_check(tp->md5sig_info,
1259 lockdep_sock_is_held(sk));
1260 if (!md5sig)
1261 return NULL;
1262
1263 hlist_for_each_entry_rcu(key, &md5sig->head, node,
1264 lockdep_sock_is_held(sk)) {
1265 if (key->family != family)
1266 continue;
1267 if (!any_l3index && key->flags & TCP_MD5SIG_FLAG_IFINDEX &&
1268 key->l3index != l3index)
1269 continue;
1270 if (family == AF_INET) {
1271 mask = inet_make_mask(key->prefixlen);
1272 match = (key->addr.a4.s_addr & mask) ==
1273 (addr->a4.s_addr & mask);
1274#if IS_ENABLED(CONFIG_IPV6)
1275 } else if (family == AF_INET6) {
1276 match = ipv6_prefix_equal(&key->addr.a6, &addr->a6,
1277 key->prefixlen);
1278#endif
1279 } else {
1280 match = false;
1281 }
1282
1283 if (match && better_md5_match(best_match, key))
1284 best_match = key;
1285 }
1286 return best_match;
1287}
1288EXPORT_SYMBOL(__tcp_md5_do_lookup);
1289
1290static struct tcp_md5sig_key *tcp_md5_do_lookup_exact(const struct sock *sk,
1291 const union tcp_md5_addr *addr,
1292 int family, u8 prefixlen,
1293 int l3index, u8 flags)
1294{
1295 const struct tcp_sock *tp = tcp_sk(sk);
1296 struct tcp_md5sig_key *key;
1297 unsigned int size = sizeof(struct in_addr);
1298 const struct tcp_md5sig_info *md5sig;
1299
1300 /* caller either holds rcu_read_lock() or socket lock */
1301 md5sig = rcu_dereference_check(tp->md5sig_info,
1302 lockdep_sock_is_held(sk));
1303 if (!md5sig)
1304 return NULL;
1305#if IS_ENABLED(CONFIG_IPV6)
1306 if (family == AF_INET6)
1307 size = sizeof(struct in6_addr);
1308#endif
1309 hlist_for_each_entry_rcu(key, &md5sig->head, node,
1310 lockdep_sock_is_held(sk)) {
1311 if (key->family != family)
1312 continue;
1313 if ((key->flags & TCP_MD5SIG_FLAG_IFINDEX) != (flags & TCP_MD5SIG_FLAG_IFINDEX))
1314 continue;
1315 if (key->l3index != l3index)
1316 continue;
1317 if (!memcmp(&key->addr, addr, size) &&
1318 key->prefixlen == prefixlen)
1319 return key;
1320 }
1321 return NULL;
1322}
1323
1324struct tcp_md5sig_key *tcp_v4_md5_lookup(const struct sock *sk,
1325 const struct sock *addr_sk)
1326{
1327 const union tcp_md5_addr *addr;
1328 int l3index;
1329
1330 l3index = l3mdev_master_ifindex_by_index(sock_net(sk),
1331 addr_sk->sk_bound_dev_if);
1332 addr = (const union tcp_md5_addr *)&addr_sk->sk_daddr;
1333 return tcp_md5_do_lookup(sk, l3index, addr, AF_INET);
1334}
1335EXPORT_SYMBOL(tcp_v4_md5_lookup);
1336
1337static int tcp_md5sig_info_add(struct sock *sk, gfp_t gfp)
1338{
1339 struct tcp_sock *tp = tcp_sk(sk);
1340 struct tcp_md5sig_info *md5sig;
1341
1342 md5sig = kmalloc(sizeof(*md5sig), gfp);
1343 if (!md5sig)
1344 return -ENOMEM;
1345
1346 sk_gso_disable(sk);
1347 INIT_HLIST_HEAD(&md5sig->head);
1348 rcu_assign_pointer(tp->md5sig_info, md5sig);
1349 return 0;
1350}
1351
1352/* This can be called on a newly created socket, from other files */
1353static int __tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr,
1354 int family, u8 prefixlen, int l3index, u8 flags,
1355 const u8 *newkey, u8 newkeylen, gfp_t gfp)
1356{
1357 /* Add Key to the list */
1358 struct tcp_md5sig_key *key;
1359 struct tcp_sock *tp = tcp_sk(sk);
1360 struct tcp_md5sig_info *md5sig;
1361
1362 key = tcp_md5_do_lookup_exact(sk, addr, family, prefixlen, l3index, flags);
1363 if (key) {
1364 /* Pre-existing entry - just update that one.
1365 * Note that the key might be used concurrently.
1366 * data_race() is telling kcsan that we do not care of
1367 * key mismatches, since changing MD5 key on live flows
1368 * can lead to packet drops.
1369 */
1370 data_race(memcpy(key->key, newkey, newkeylen));
1371
1372 /* Pairs with READ_ONCE() in tcp_md5_hash_key().
1373 * Also note that a reader could catch new key->keylen value
1374 * but old key->key[], this is the reason we use __GFP_ZERO
1375 * at sock_kmalloc() time below these lines.
1376 */
1377 WRITE_ONCE(key->keylen, newkeylen);
1378
1379 return 0;
1380 }
1381
1382 md5sig = rcu_dereference_protected(tp->md5sig_info,
1383 lockdep_sock_is_held(sk));
1384
1385 key = sock_kmalloc(sk, sizeof(*key), gfp | __GFP_ZERO);
1386 if (!key)
1387 return -ENOMEM;
1388
1389 memcpy(key->key, newkey, newkeylen);
1390 key->keylen = newkeylen;
1391 key->family = family;
1392 key->prefixlen = prefixlen;
1393 key->l3index = l3index;
1394 key->flags = flags;
1395 memcpy(&key->addr, addr,
1396 (IS_ENABLED(CONFIG_IPV6) && family == AF_INET6) ? sizeof(struct in6_addr) :
1397 sizeof(struct in_addr));
1398 hlist_add_head_rcu(&key->node, &md5sig->head);
1399 return 0;
1400}
1401
1402int tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr,
1403 int family, u8 prefixlen, int l3index, u8 flags,
1404 const u8 *newkey, u8 newkeylen)
1405{
1406 struct tcp_sock *tp = tcp_sk(sk);
1407
1408 if (!rcu_dereference_protected(tp->md5sig_info, lockdep_sock_is_held(sk))) {
1409 if (tcp_md5_alloc_sigpool())
1410 return -ENOMEM;
1411
1412 if (tcp_md5sig_info_add(sk, GFP_KERNEL)) {
1413 tcp_md5_release_sigpool();
1414 return -ENOMEM;
1415 }
1416
1417 if (!static_branch_inc(&tcp_md5_needed.key)) {
1418 struct tcp_md5sig_info *md5sig;
1419
1420 md5sig = rcu_dereference_protected(tp->md5sig_info, lockdep_sock_is_held(sk));
1421 rcu_assign_pointer(tp->md5sig_info, NULL);
1422 kfree_rcu(md5sig, rcu);
1423 tcp_md5_release_sigpool();
1424 return -EUSERS;
1425 }
1426 }
1427
1428 return __tcp_md5_do_add(sk, addr, family, prefixlen, l3index, flags,
1429 newkey, newkeylen, GFP_KERNEL);
1430}
1431EXPORT_SYMBOL(tcp_md5_do_add);
1432
1433int tcp_md5_key_copy(struct sock *sk, const union tcp_md5_addr *addr,
1434 int family, u8 prefixlen, int l3index,
1435 struct tcp_md5sig_key *key)
1436{
1437 struct tcp_sock *tp = tcp_sk(sk);
1438
1439 if (!rcu_dereference_protected(tp->md5sig_info, lockdep_sock_is_held(sk))) {
1440 tcp_md5_add_sigpool();
1441
1442 if (tcp_md5sig_info_add(sk, sk_gfp_mask(sk, GFP_ATOMIC))) {
1443 tcp_md5_release_sigpool();
1444 return -ENOMEM;
1445 }
1446
1447 if (!static_key_fast_inc_not_disabled(&tcp_md5_needed.key.key)) {
1448 struct tcp_md5sig_info *md5sig;
1449
1450 md5sig = rcu_dereference_protected(tp->md5sig_info, lockdep_sock_is_held(sk));
1451 net_warn_ratelimited("Too many TCP-MD5 keys in the system\n");
1452 rcu_assign_pointer(tp->md5sig_info, NULL);
1453 kfree_rcu(md5sig, rcu);
1454 tcp_md5_release_sigpool();
1455 return -EUSERS;
1456 }
1457 }
1458
1459 return __tcp_md5_do_add(sk, addr, family, prefixlen, l3index,
1460 key->flags, key->key, key->keylen,
1461 sk_gfp_mask(sk, GFP_ATOMIC));
1462}
1463EXPORT_SYMBOL(tcp_md5_key_copy);
1464
1465int tcp_md5_do_del(struct sock *sk, const union tcp_md5_addr *addr, int family,
1466 u8 prefixlen, int l3index, u8 flags)
1467{
1468 struct tcp_md5sig_key *key;
1469
1470 key = tcp_md5_do_lookup_exact(sk, addr, family, prefixlen, l3index, flags);
1471 if (!key)
1472 return -ENOENT;
1473 hlist_del_rcu(&key->node);
1474 atomic_sub(sizeof(*key), &sk->sk_omem_alloc);
1475 kfree_rcu(key, rcu);
1476 return 0;
1477}
1478EXPORT_SYMBOL(tcp_md5_do_del);
1479
1480void tcp_clear_md5_list(struct sock *sk)
1481{
1482 struct tcp_sock *tp = tcp_sk(sk);
1483 struct tcp_md5sig_key *key;
1484 struct hlist_node *n;
1485 struct tcp_md5sig_info *md5sig;
1486
1487 md5sig = rcu_dereference_protected(tp->md5sig_info, 1);
1488
1489 hlist_for_each_entry_safe(key, n, &md5sig->head, node) {
1490 hlist_del_rcu(&key->node);
1491 atomic_sub(sizeof(*key), &sk->sk_omem_alloc);
1492 kfree_rcu(key, rcu);
1493 }
1494}
1495
1496static int tcp_v4_parse_md5_keys(struct sock *sk, int optname,
1497 sockptr_t optval, int optlen)
1498{
1499 struct tcp_md5sig cmd;
1500 struct sockaddr_in *sin = (struct sockaddr_in *)&cmd.tcpm_addr;
1501 const union tcp_md5_addr *addr;
1502 u8 prefixlen = 32;
1503 int l3index = 0;
1504 bool l3flag;
1505 u8 flags;
1506
1507 if (optlen < sizeof(cmd))
1508 return -EINVAL;
1509
1510 if (copy_from_sockptr(&cmd, optval, sizeof(cmd)))
1511 return -EFAULT;
1512
1513 if (sin->sin_family != AF_INET)
1514 return -EINVAL;
1515
1516 flags = cmd.tcpm_flags & TCP_MD5SIG_FLAG_IFINDEX;
1517 l3flag = cmd.tcpm_flags & TCP_MD5SIG_FLAG_IFINDEX;
1518
1519 if (optname == TCP_MD5SIG_EXT &&
1520 cmd.tcpm_flags & TCP_MD5SIG_FLAG_PREFIX) {
1521 prefixlen = cmd.tcpm_prefixlen;
1522 if (prefixlen > 32)
1523 return -EINVAL;
1524 }
1525
1526 if (optname == TCP_MD5SIG_EXT && cmd.tcpm_ifindex &&
1527 cmd.tcpm_flags & TCP_MD5SIG_FLAG_IFINDEX) {
1528 struct net_device *dev;
1529
1530 rcu_read_lock();
1531 dev = dev_get_by_index_rcu(sock_net(sk), cmd.tcpm_ifindex);
1532 if (dev && netif_is_l3_master(dev))
1533 l3index = dev->ifindex;
1534
1535 rcu_read_unlock();
1536
1537 /* ok to reference set/not set outside of rcu;
1538 * right now device MUST be an L3 master
1539 */
1540 if (!dev || !l3index)
1541 return -EINVAL;
1542 }
1543
1544 addr = (union tcp_md5_addr *)&sin->sin_addr.s_addr;
1545
1546 if (!cmd.tcpm_keylen)
1547 return tcp_md5_do_del(sk, addr, AF_INET, prefixlen, l3index, flags);
1548
1549 if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN)
1550 return -EINVAL;
1551
1552 /* Don't allow keys for peers that have a matching TCP-AO key.
1553 * See the comment in tcp_ao_add_cmd()
1554 */
1555 if (tcp_ao_required(sk, addr, AF_INET, l3flag ? l3index : -1, false))
1556 return -EKEYREJECTED;
1557
1558 return tcp_md5_do_add(sk, addr, AF_INET, prefixlen, l3index, flags,
1559 cmd.tcpm_key, cmd.tcpm_keylen);
1560}
1561
1562static int tcp_v4_md5_hash_headers(struct tcp_sigpool *hp,
1563 __be32 daddr, __be32 saddr,
1564 const struct tcphdr *th, int nbytes)
1565{
1566 struct tcp4_pseudohdr *bp;
1567 struct scatterlist sg;
1568 struct tcphdr *_th;
1569
1570 bp = hp->scratch;
1571 bp->saddr = saddr;
1572 bp->daddr = daddr;
1573 bp->pad = 0;
1574 bp->protocol = IPPROTO_TCP;
1575 bp->len = cpu_to_be16(nbytes);
1576
1577 _th = (struct tcphdr *)(bp + 1);
1578 memcpy(_th, th, sizeof(*th));
1579 _th->check = 0;
1580
1581 sg_init_one(&sg, bp, sizeof(*bp) + sizeof(*th));
1582 ahash_request_set_crypt(hp->req, &sg, NULL,
1583 sizeof(*bp) + sizeof(*th));
1584 return crypto_ahash_update(hp->req);
1585}
1586
1587static int tcp_v4_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key,
1588 __be32 daddr, __be32 saddr, const struct tcphdr *th)
1589{
1590 struct tcp_sigpool hp;
1591
1592 if (tcp_sigpool_start(tcp_md5_sigpool_id, &hp))
1593 goto clear_hash_nostart;
1594
1595 if (crypto_ahash_init(hp.req))
1596 goto clear_hash;
1597 if (tcp_v4_md5_hash_headers(&hp, daddr, saddr, th, th->doff << 2))
1598 goto clear_hash;
1599 if (tcp_md5_hash_key(&hp, key))
1600 goto clear_hash;
1601 ahash_request_set_crypt(hp.req, NULL, md5_hash, 0);
1602 if (crypto_ahash_final(hp.req))
1603 goto clear_hash;
1604
1605 tcp_sigpool_end(&hp);
1606 return 0;
1607
1608clear_hash:
1609 tcp_sigpool_end(&hp);
1610clear_hash_nostart:
1611 memset(md5_hash, 0, 16);
1612 return 1;
1613}
1614
1615int tcp_v4_md5_hash_skb(char *md5_hash, const struct tcp_md5sig_key *key,
1616 const struct sock *sk,
1617 const struct sk_buff *skb)
1618{
1619 const struct tcphdr *th = tcp_hdr(skb);
1620 struct tcp_sigpool hp;
1621 __be32 saddr, daddr;
1622
1623 if (sk) { /* valid for establish/request sockets */
1624 saddr = sk->sk_rcv_saddr;
1625 daddr = sk->sk_daddr;
1626 } else {
1627 const struct iphdr *iph = ip_hdr(skb);
1628 saddr = iph->saddr;
1629 daddr = iph->daddr;
1630 }
1631
1632 if (tcp_sigpool_start(tcp_md5_sigpool_id, &hp))
1633 goto clear_hash_nostart;
1634
1635 if (crypto_ahash_init(hp.req))
1636 goto clear_hash;
1637
1638 if (tcp_v4_md5_hash_headers(&hp, daddr, saddr, th, skb->len))
1639 goto clear_hash;
1640 if (tcp_sigpool_hash_skb_data(&hp, skb, th->doff << 2))
1641 goto clear_hash;
1642 if (tcp_md5_hash_key(&hp, key))
1643 goto clear_hash;
1644 ahash_request_set_crypt(hp.req, NULL, md5_hash, 0);
1645 if (crypto_ahash_final(hp.req))
1646 goto clear_hash;
1647
1648 tcp_sigpool_end(&hp);
1649 return 0;
1650
1651clear_hash:
1652 tcp_sigpool_end(&hp);
1653clear_hash_nostart:
1654 memset(md5_hash, 0, 16);
1655 return 1;
1656}
1657EXPORT_SYMBOL(tcp_v4_md5_hash_skb);
1658
1659#endif
1660
1661static void tcp_v4_init_req(struct request_sock *req,
1662 const struct sock *sk_listener,
1663 struct sk_buff *skb)
1664{
1665 struct inet_request_sock *ireq = inet_rsk(req);
1666 struct net *net = sock_net(sk_listener);
1667
1668 sk_rcv_saddr_set(req_to_sk(req), ip_hdr(skb)->daddr);
1669 sk_daddr_set(req_to_sk(req), ip_hdr(skb)->saddr);
1670 RCU_INIT_POINTER(ireq->ireq_opt, tcp_v4_save_options(net, skb));
1671}
1672
1673static struct dst_entry *tcp_v4_route_req(const struct sock *sk,
1674 struct sk_buff *skb,
1675 struct flowi *fl,
1676 struct request_sock *req)
1677{
1678 tcp_v4_init_req(req, sk, skb);
1679
1680 if (security_inet_conn_request(sk, skb, req))
1681 return NULL;
1682
1683 return inet_csk_route_req(sk, &fl->u.ip4, req);
1684}
1685
1686struct request_sock_ops tcp_request_sock_ops __read_mostly = {
1687 .family = PF_INET,
1688 .obj_size = sizeof(struct tcp_request_sock),
1689 .rtx_syn_ack = tcp_rtx_synack,
1690 .send_ack = tcp_v4_reqsk_send_ack,
1691 .destructor = tcp_v4_reqsk_destructor,
1692 .send_reset = tcp_v4_send_reset,
1693 .syn_ack_timeout = tcp_syn_ack_timeout,
1694};
1695
1696const struct tcp_request_sock_ops tcp_request_sock_ipv4_ops = {
1697 .mss_clamp = TCP_MSS_DEFAULT,
1698#ifdef CONFIG_TCP_MD5SIG
1699 .req_md5_lookup = tcp_v4_md5_lookup,
1700 .calc_md5_hash = tcp_v4_md5_hash_skb,
1701#endif
1702#ifdef CONFIG_TCP_AO
1703 .ao_lookup = tcp_v4_ao_lookup_rsk,
1704 .ao_calc_key = tcp_v4_ao_calc_key_rsk,
1705 .ao_synack_hash = tcp_v4_ao_synack_hash,
1706#endif
1707#ifdef CONFIG_SYN_COOKIES
1708 .cookie_init_seq = cookie_v4_init_sequence,
1709#endif
1710 .route_req = tcp_v4_route_req,
1711 .init_seq = tcp_v4_init_seq,
1712 .init_ts_off = tcp_v4_init_ts_off,
1713 .send_synack = tcp_v4_send_synack,
1714};
1715
1716int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
1717{
1718 /* Never answer to SYNs send to broadcast or multicast */
1719 if (skb_rtable(skb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
1720 goto drop;
1721
1722 return tcp_conn_request(&tcp_request_sock_ops,
1723 &tcp_request_sock_ipv4_ops, sk, skb);
1724
1725drop:
1726 tcp_listendrop(sk);
1727 return 0;
1728}
1729EXPORT_SYMBOL(tcp_v4_conn_request);
1730
1731
1732/*
1733 * The three way handshake has completed - we got a valid synack -
1734 * now create the new socket.
1735 */
1736struct sock *tcp_v4_syn_recv_sock(const struct sock *sk, struct sk_buff *skb,
1737 struct request_sock *req,
1738 struct dst_entry *dst,
1739 struct request_sock *req_unhash,
1740 bool *own_req)
1741{
1742 struct inet_request_sock *ireq;
1743 bool found_dup_sk = false;
1744 struct inet_sock *newinet;
1745 struct tcp_sock *newtp;
1746 struct sock *newsk;
1747#ifdef CONFIG_TCP_MD5SIG
1748 const union tcp_md5_addr *addr;
1749 struct tcp_md5sig_key *key;
1750 int l3index;
1751#endif
1752 struct ip_options_rcu *inet_opt;
1753
1754 if (sk_acceptq_is_full(sk))
1755 goto exit_overflow;
1756
1757 newsk = tcp_create_openreq_child(sk, req, skb);
1758 if (!newsk)
1759 goto exit_nonewsk;
1760
1761 newsk->sk_gso_type = SKB_GSO_TCPV4;
1762 inet_sk_rx_dst_set(newsk, skb);
1763
1764 newtp = tcp_sk(newsk);
1765 newinet = inet_sk(newsk);
1766 ireq = inet_rsk(req);
1767 sk_daddr_set(newsk, ireq->ir_rmt_addr);
1768 sk_rcv_saddr_set(newsk, ireq->ir_loc_addr);
1769 newsk->sk_bound_dev_if = ireq->ir_iif;
1770 newinet->inet_saddr = ireq->ir_loc_addr;
1771 inet_opt = rcu_dereference(ireq->ireq_opt);
1772 RCU_INIT_POINTER(newinet->inet_opt, inet_opt);
1773 newinet->mc_index = inet_iif(skb);
1774 newinet->mc_ttl = ip_hdr(skb)->ttl;
1775 newinet->rcv_tos = ip_hdr(skb)->tos;
1776 inet_csk(newsk)->icsk_ext_hdr_len = 0;
1777 if (inet_opt)
1778 inet_csk(newsk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
1779 atomic_set(&newinet->inet_id, get_random_u16());
1780
1781 /* Set ToS of the new socket based upon the value of incoming SYN.
1782 * ECT bits are set later in tcp_init_transfer().
1783 */
1784 if (READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_reflect_tos))
1785 newinet->tos = tcp_rsk(req)->syn_tos & ~INET_ECN_MASK;
1786
1787 if (!dst) {
1788 dst = inet_csk_route_child_sock(sk, newsk, req);
1789 if (!dst)
1790 goto put_and_exit;
1791 } else {
1792 /* syncookie case : see end of cookie_v4_check() */
1793 }
1794 sk_setup_caps(newsk, dst);
1795
1796 tcp_ca_openreq_child(newsk, dst);
1797
1798 tcp_sync_mss(newsk, dst_mtu(dst));
1799 newtp->advmss = tcp_mss_clamp(tcp_sk(sk), dst_metric_advmss(dst));
1800
1801 tcp_initialize_rcv_mss(newsk);
1802
1803#ifdef CONFIG_TCP_MD5SIG
1804 l3index = l3mdev_master_ifindex_by_index(sock_net(sk), ireq->ir_iif);
1805 /* Copy over the MD5 key from the original socket */
1806 addr = (union tcp_md5_addr *)&newinet->inet_daddr;
1807 key = tcp_md5_do_lookup(sk, l3index, addr, AF_INET);
1808 if (key && !tcp_rsk_used_ao(req)) {
1809 if (tcp_md5_key_copy(newsk, addr, AF_INET, 32, l3index, key))
1810 goto put_and_exit;
1811 sk_gso_disable(newsk);
1812 }
1813#endif
1814#ifdef CONFIG_TCP_AO
1815 if (tcp_ao_copy_all_matching(sk, newsk, req, skb, AF_INET))
1816 goto put_and_exit; /* OOM, release back memory */
1817#endif
1818
1819 if (__inet_inherit_port(sk, newsk) < 0)
1820 goto put_and_exit;
1821 *own_req = inet_ehash_nolisten(newsk, req_to_sk(req_unhash),
1822 &found_dup_sk);
1823 if (likely(*own_req)) {
1824 tcp_move_syn(newtp, req);
1825 ireq->ireq_opt = NULL;
1826 } else {
1827 newinet->inet_opt = NULL;
1828
1829 if (!req_unhash && found_dup_sk) {
1830 /* This code path should only be executed in the
1831 * syncookie case only
1832 */
1833 bh_unlock_sock(newsk);
1834 sock_put(newsk);
1835 newsk = NULL;
1836 }
1837 }
1838 return newsk;
1839
1840exit_overflow:
1841 NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
1842exit_nonewsk:
1843 dst_release(dst);
1844exit:
1845 tcp_listendrop(sk);
1846 return NULL;
1847put_and_exit:
1848 newinet->inet_opt = NULL;
1849 inet_csk_prepare_forced_close(newsk);
1850 tcp_done(newsk);
1851 goto exit;
1852}
1853EXPORT_SYMBOL(tcp_v4_syn_recv_sock);
1854
1855static struct sock *tcp_v4_cookie_check(struct sock *sk, struct sk_buff *skb)
1856{
1857#ifdef CONFIG_SYN_COOKIES
1858 const struct tcphdr *th = tcp_hdr(skb);
1859
1860 if (!th->syn)
1861 sk = cookie_v4_check(sk, skb);
1862#endif
1863 return sk;
1864}
1865
1866u16 tcp_v4_get_syncookie(struct sock *sk, struct iphdr *iph,
1867 struct tcphdr *th, u32 *cookie)
1868{
1869 u16 mss = 0;
1870#ifdef CONFIG_SYN_COOKIES
1871 mss = tcp_get_syncookie_mss(&tcp_request_sock_ops,
1872 &tcp_request_sock_ipv4_ops, sk, th);
1873 if (mss) {
1874 *cookie = __cookie_v4_init_sequence(iph, th, &mss);
1875 tcp_synq_overflow(sk);
1876 }
1877#endif
1878 return mss;
1879}
1880
1881INDIRECT_CALLABLE_DECLARE(struct dst_entry *ipv4_dst_check(struct dst_entry *,
1882 u32));
1883/* The socket must have it's spinlock held when we get
1884 * here, unless it is a TCP_LISTEN socket.
1885 *
1886 * We have a potential double-lock case here, so even when
1887 * doing backlog processing we use the BH locking scheme.
1888 * This is because we cannot sleep with the original spinlock
1889 * held.
1890 */
1891int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
1892{
1893 enum skb_drop_reason reason;
1894 struct sock *rsk;
1895
1896 if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
1897 struct dst_entry *dst;
1898
1899 dst = rcu_dereference_protected(sk->sk_rx_dst,
1900 lockdep_sock_is_held(sk));
1901
1902 sock_rps_save_rxhash(sk, skb);
1903 sk_mark_napi_id(sk, skb);
1904 if (dst) {
1905 if (sk->sk_rx_dst_ifindex != skb->skb_iif ||
1906 !INDIRECT_CALL_1(dst->ops->check, ipv4_dst_check,
1907 dst, 0)) {
1908 RCU_INIT_POINTER(sk->sk_rx_dst, NULL);
1909 dst_release(dst);
1910 }
1911 }
1912 tcp_rcv_established(sk, skb);
1913 return 0;
1914 }
1915
1916 if (tcp_checksum_complete(skb))
1917 goto csum_err;
1918
1919 if (sk->sk_state == TCP_LISTEN) {
1920 struct sock *nsk = tcp_v4_cookie_check(sk, skb);
1921
1922 if (!nsk)
1923 return 0;
1924 if (nsk != sk) {
1925 reason = tcp_child_process(sk, nsk, skb);
1926 if (reason) {
1927 rsk = nsk;
1928 goto reset;
1929 }
1930 return 0;
1931 }
1932 } else
1933 sock_rps_save_rxhash(sk, skb);
1934
1935 reason = tcp_rcv_state_process(sk, skb);
1936 if (reason) {
1937 rsk = sk;
1938 goto reset;
1939 }
1940 return 0;
1941
1942reset:
1943 tcp_v4_send_reset(rsk, skb);
1944discard:
1945 kfree_skb_reason(skb, reason);
1946 /* Be careful here. If this function gets more complicated and
1947 * gcc suffers from register pressure on the x86, sk (in %ebx)
1948 * might be destroyed here. This current version compiles correctly,
1949 * but you have been warned.
1950 */
1951 return 0;
1952
1953csum_err:
1954 reason = SKB_DROP_REASON_TCP_CSUM;
1955 trace_tcp_bad_csum(skb);
1956 TCP_INC_STATS(sock_net(sk), TCP_MIB_CSUMERRORS);
1957 TCP_INC_STATS(sock_net(sk), TCP_MIB_INERRS);
1958 goto discard;
1959}
1960EXPORT_SYMBOL(tcp_v4_do_rcv);
1961
1962int tcp_v4_early_demux(struct sk_buff *skb)
1963{
1964 struct net *net = dev_net(skb->dev);
1965 const struct iphdr *iph;
1966 const struct tcphdr *th;
1967 struct sock *sk;
1968
1969 if (skb->pkt_type != PACKET_HOST)
1970 return 0;
1971
1972 if (!pskb_may_pull(skb, skb_transport_offset(skb) + sizeof(struct tcphdr)))
1973 return 0;
1974
1975 iph = ip_hdr(skb);
1976 th = tcp_hdr(skb);
1977
1978 if (th->doff < sizeof(struct tcphdr) / 4)
1979 return 0;
1980
1981 sk = __inet_lookup_established(net, net->ipv4.tcp_death_row.hashinfo,
1982 iph->saddr, th->source,
1983 iph->daddr, ntohs(th->dest),
1984 skb->skb_iif, inet_sdif(skb));
1985 if (sk) {
1986 skb->sk = sk;
1987 skb->destructor = sock_edemux;
1988 if (sk_fullsock(sk)) {
1989 struct dst_entry *dst = rcu_dereference(sk->sk_rx_dst);
1990
1991 if (dst)
1992 dst = dst_check(dst, 0);
1993 if (dst &&
1994 sk->sk_rx_dst_ifindex == skb->skb_iif)
1995 skb_dst_set_noref(skb, dst);
1996 }
1997 }
1998 return 0;
1999}
2000
2001bool tcp_add_backlog(struct sock *sk, struct sk_buff *skb,
2002 enum skb_drop_reason *reason)
2003{
2004 u32 tail_gso_size, tail_gso_segs;
2005 struct skb_shared_info *shinfo;
2006 const struct tcphdr *th;
2007 struct tcphdr *thtail;
2008 struct sk_buff *tail;
2009 unsigned int hdrlen;
2010 bool fragstolen;
2011 u32 gso_segs;
2012 u32 gso_size;
2013 u64 limit;
2014 int delta;
2015
2016 /* In case all data was pulled from skb frags (in __pskb_pull_tail()),
2017 * we can fix skb->truesize to its real value to avoid future drops.
2018 * This is valid because skb is not yet charged to the socket.
2019 * It has been noticed pure SACK packets were sometimes dropped
2020 * (if cooked by drivers without copybreak feature).
2021 */
2022 skb_condense(skb);
2023
2024 skb_dst_drop(skb);
2025
2026 if (unlikely(tcp_checksum_complete(skb))) {
2027 bh_unlock_sock(sk);
2028 trace_tcp_bad_csum(skb);
2029 *reason = SKB_DROP_REASON_TCP_CSUM;
2030 __TCP_INC_STATS(sock_net(sk), TCP_MIB_CSUMERRORS);
2031 __TCP_INC_STATS(sock_net(sk), TCP_MIB_INERRS);
2032 return true;
2033 }
2034
2035 /* Attempt coalescing to last skb in backlog, even if we are
2036 * above the limits.
2037 * This is okay because skb capacity is limited to MAX_SKB_FRAGS.
2038 */
2039 th = (const struct tcphdr *)skb->data;
2040 hdrlen = th->doff * 4;
2041
2042 tail = sk->sk_backlog.tail;
2043 if (!tail)
2044 goto no_coalesce;
2045 thtail = (struct tcphdr *)tail->data;
2046
2047 if (TCP_SKB_CB(tail)->end_seq != TCP_SKB_CB(skb)->seq ||
2048 TCP_SKB_CB(tail)->ip_dsfield != TCP_SKB_CB(skb)->ip_dsfield ||
2049 ((TCP_SKB_CB(tail)->tcp_flags |
2050 TCP_SKB_CB(skb)->tcp_flags) & (TCPHDR_SYN | TCPHDR_RST | TCPHDR_URG)) ||
2051 !((TCP_SKB_CB(tail)->tcp_flags &
2052 TCP_SKB_CB(skb)->tcp_flags) & TCPHDR_ACK) ||
2053 ((TCP_SKB_CB(tail)->tcp_flags ^
2054 TCP_SKB_CB(skb)->tcp_flags) & (TCPHDR_ECE | TCPHDR_CWR)) ||
2055#ifdef CONFIG_TLS_DEVICE
2056 tail->decrypted != skb->decrypted ||
2057#endif
2058 !mptcp_skb_can_collapse(tail, skb) ||
2059 thtail->doff != th->doff ||
2060 memcmp(thtail + 1, th + 1, hdrlen - sizeof(*th)))
2061 goto no_coalesce;
2062
2063 __skb_pull(skb, hdrlen);
2064
2065 shinfo = skb_shinfo(skb);
2066 gso_size = shinfo->gso_size ?: skb->len;
2067 gso_segs = shinfo->gso_segs ?: 1;
2068
2069 shinfo = skb_shinfo(tail);
2070 tail_gso_size = shinfo->gso_size ?: (tail->len - hdrlen);
2071 tail_gso_segs = shinfo->gso_segs ?: 1;
2072
2073 if (skb_try_coalesce(tail, skb, &fragstolen, &delta)) {
2074 TCP_SKB_CB(tail)->end_seq = TCP_SKB_CB(skb)->end_seq;
2075
2076 if (likely(!before(TCP_SKB_CB(skb)->ack_seq, TCP_SKB_CB(tail)->ack_seq))) {
2077 TCP_SKB_CB(tail)->ack_seq = TCP_SKB_CB(skb)->ack_seq;
2078 thtail->window = th->window;
2079 }
2080
2081 /* We have to update both TCP_SKB_CB(tail)->tcp_flags and
2082 * thtail->fin, so that the fast path in tcp_rcv_established()
2083 * is not entered if we append a packet with a FIN.
2084 * SYN, RST, URG are not present.
2085 * ACK is set on both packets.
2086 * PSH : we do not really care in TCP stack,
2087 * at least for 'GRO' packets.
2088 */
2089 thtail->fin |= th->fin;
2090 TCP_SKB_CB(tail)->tcp_flags |= TCP_SKB_CB(skb)->tcp_flags;
2091
2092 if (TCP_SKB_CB(skb)->has_rxtstamp) {
2093 TCP_SKB_CB(tail)->has_rxtstamp = true;
2094 tail->tstamp = skb->tstamp;
2095 skb_hwtstamps(tail)->hwtstamp = skb_hwtstamps(skb)->hwtstamp;
2096 }
2097
2098 /* Not as strict as GRO. We only need to carry mss max value */
2099 shinfo->gso_size = max(gso_size, tail_gso_size);
2100 shinfo->gso_segs = min_t(u32, gso_segs + tail_gso_segs, 0xFFFF);
2101
2102 sk->sk_backlog.len += delta;
2103 __NET_INC_STATS(sock_net(sk),
2104 LINUX_MIB_TCPBACKLOGCOALESCE);
2105 kfree_skb_partial(skb, fragstolen);
2106 return false;
2107 }
2108 __skb_push(skb, hdrlen);
2109
2110no_coalesce:
2111 /* sk->sk_backlog.len is reset only at the end of __release_sock().
2112 * Both sk->sk_backlog.len and sk->sk_rmem_alloc could reach
2113 * sk_rcvbuf in normal conditions.
2114 */
2115 limit = ((u64)READ_ONCE(sk->sk_rcvbuf)) << 1;
2116
2117 limit += ((u32)READ_ONCE(sk->sk_sndbuf)) >> 1;
2118
2119 /* Only socket owner can try to collapse/prune rx queues
2120 * to reduce memory overhead, so add a little headroom here.
2121 * Few sockets backlog are possibly concurrently non empty.
2122 */
2123 limit += 64 * 1024;
2124
2125 limit = min_t(u64, limit, UINT_MAX);
2126
2127 if (unlikely(sk_add_backlog(sk, skb, limit))) {
2128 bh_unlock_sock(sk);
2129 *reason = SKB_DROP_REASON_SOCKET_BACKLOG;
2130 __NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPBACKLOGDROP);
2131 return true;
2132 }
2133 return false;
2134}
2135EXPORT_SYMBOL(tcp_add_backlog);
2136
2137int tcp_filter(struct sock *sk, struct sk_buff *skb)
2138{
2139 struct tcphdr *th = (struct tcphdr *)skb->data;
2140
2141 return sk_filter_trim_cap(sk, skb, th->doff * 4);
2142}
2143EXPORT_SYMBOL(tcp_filter);
2144
2145static void tcp_v4_restore_cb(struct sk_buff *skb)
2146{
2147 memmove(IPCB(skb), &TCP_SKB_CB(skb)->header.h4,
2148 sizeof(struct inet_skb_parm));
2149}
2150
2151static void tcp_v4_fill_cb(struct sk_buff *skb, const struct iphdr *iph,
2152 const struct tcphdr *th)
2153{
2154 /* This is tricky : We move IPCB at its correct location into TCP_SKB_CB()
2155 * barrier() makes sure compiler wont play fool^Waliasing games.
2156 */
2157 memmove(&TCP_SKB_CB(skb)->header.h4, IPCB(skb),
2158 sizeof(struct inet_skb_parm));
2159 barrier();
2160
2161 TCP_SKB_CB(skb)->seq = ntohl(th->seq);
2162 TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
2163 skb->len - th->doff * 4);
2164 TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
2165 TCP_SKB_CB(skb)->tcp_flags = tcp_flag_byte(th);
2166 TCP_SKB_CB(skb)->tcp_tw_isn = 0;
2167 TCP_SKB_CB(skb)->ip_dsfield = ipv4_get_dsfield(iph);
2168 TCP_SKB_CB(skb)->sacked = 0;
2169 TCP_SKB_CB(skb)->has_rxtstamp =
2170 skb->tstamp || skb_hwtstamps(skb)->hwtstamp;
2171}
2172
2173/*
2174 * From tcp_input.c
2175 */
2176
2177int tcp_v4_rcv(struct sk_buff *skb)
2178{
2179 struct net *net = dev_net(skb->dev);
2180 enum skb_drop_reason drop_reason;
2181 int sdif = inet_sdif(skb);
2182 int dif = inet_iif(skb);
2183 const struct iphdr *iph;
2184 const struct tcphdr *th;
2185 bool refcounted;
2186 struct sock *sk;
2187 int ret;
2188
2189 drop_reason = SKB_DROP_REASON_NOT_SPECIFIED;
2190 if (skb->pkt_type != PACKET_HOST)
2191 goto discard_it;
2192
2193 /* Count it even if it's bad */
2194 __TCP_INC_STATS(net, TCP_MIB_INSEGS);
2195
2196 if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
2197 goto discard_it;
2198
2199 th = (const struct tcphdr *)skb->data;
2200
2201 if (unlikely(th->doff < sizeof(struct tcphdr) / 4)) {
2202 drop_reason = SKB_DROP_REASON_PKT_TOO_SMALL;
2203 goto bad_packet;
2204 }
2205 if (!pskb_may_pull(skb, th->doff * 4))
2206 goto discard_it;
2207
2208 /* An explanation is required here, I think.
2209 * Packet length and doff are validated by header prediction,
2210 * provided case of th->doff==0 is eliminated.
2211 * So, we defer the checks. */
2212
2213 if (skb_checksum_init(skb, IPPROTO_TCP, inet_compute_pseudo))
2214 goto csum_error;
2215
2216 th = (const struct tcphdr *)skb->data;
2217 iph = ip_hdr(skb);
2218lookup:
2219 sk = __inet_lookup_skb(net->ipv4.tcp_death_row.hashinfo,
2220 skb, __tcp_hdrlen(th), th->source,
2221 th->dest, sdif, &refcounted);
2222 if (!sk)
2223 goto no_tcp_socket;
2224
2225process:
2226 if (sk->sk_state == TCP_TIME_WAIT)
2227 goto do_time_wait;
2228
2229 if (sk->sk_state == TCP_NEW_SYN_RECV) {
2230 struct request_sock *req = inet_reqsk(sk);
2231 bool req_stolen = false;
2232 struct sock *nsk;
2233
2234 sk = req->rsk_listener;
2235 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
2236 drop_reason = SKB_DROP_REASON_XFRM_POLICY;
2237 else
2238 drop_reason = tcp_inbound_hash(sk, req, skb,
2239 &iph->saddr, &iph->daddr,
2240 AF_INET, dif, sdif);
2241 if (unlikely(drop_reason)) {
2242 sk_drops_add(sk, skb);
2243 reqsk_put(req);
2244 goto discard_it;
2245 }
2246 if (tcp_checksum_complete(skb)) {
2247 reqsk_put(req);
2248 goto csum_error;
2249 }
2250 if (unlikely(sk->sk_state != TCP_LISTEN)) {
2251 nsk = reuseport_migrate_sock(sk, req_to_sk(req), skb);
2252 if (!nsk) {
2253 inet_csk_reqsk_queue_drop_and_put(sk, req);
2254 goto lookup;
2255 }
2256 sk = nsk;
2257 /* reuseport_migrate_sock() has already held one sk_refcnt
2258 * before returning.
2259 */
2260 } else {
2261 /* We own a reference on the listener, increase it again
2262 * as we might lose it too soon.
2263 */
2264 sock_hold(sk);
2265 }
2266 refcounted = true;
2267 nsk = NULL;
2268 if (!tcp_filter(sk, skb)) {
2269 th = (const struct tcphdr *)skb->data;
2270 iph = ip_hdr(skb);
2271 tcp_v4_fill_cb(skb, iph, th);
2272 nsk = tcp_check_req(sk, skb, req, false, &req_stolen);
2273 } else {
2274 drop_reason = SKB_DROP_REASON_SOCKET_FILTER;
2275 }
2276 if (!nsk) {
2277 reqsk_put(req);
2278 if (req_stolen) {
2279 /* Another cpu got exclusive access to req
2280 * and created a full blown socket.
2281 * Try to feed this packet to this socket
2282 * instead of discarding it.
2283 */
2284 tcp_v4_restore_cb(skb);
2285 sock_put(sk);
2286 goto lookup;
2287 }
2288 goto discard_and_relse;
2289 }
2290 nf_reset_ct(skb);
2291 if (nsk == sk) {
2292 reqsk_put(req);
2293 tcp_v4_restore_cb(skb);
2294 } else {
2295 drop_reason = tcp_child_process(sk, nsk, skb);
2296 if (drop_reason) {
2297 tcp_v4_send_reset(nsk, skb);
2298 goto discard_and_relse;
2299 }
2300 sock_put(sk);
2301 return 0;
2302 }
2303 }
2304
2305 if (static_branch_unlikely(&ip4_min_ttl)) {
2306 /* min_ttl can be changed concurrently from do_ip_setsockopt() */
2307 if (unlikely(iph->ttl < READ_ONCE(inet_sk(sk)->min_ttl))) {
2308 __NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP);
2309 drop_reason = SKB_DROP_REASON_TCP_MINTTL;
2310 goto discard_and_relse;
2311 }
2312 }
2313
2314 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb)) {
2315 drop_reason = SKB_DROP_REASON_XFRM_POLICY;
2316 goto discard_and_relse;
2317 }
2318
2319 drop_reason = tcp_inbound_hash(sk, NULL, skb, &iph->saddr, &iph->daddr,
2320 AF_INET, dif, sdif);
2321 if (drop_reason)
2322 goto discard_and_relse;
2323
2324 nf_reset_ct(skb);
2325
2326 if (tcp_filter(sk, skb)) {
2327 drop_reason = SKB_DROP_REASON_SOCKET_FILTER;
2328 goto discard_and_relse;
2329 }
2330 th = (const struct tcphdr *)skb->data;
2331 iph = ip_hdr(skb);
2332 tcp_v4_fill_cb(skb, iph, th);
2333
2334 skb->dev = NULL;
2335
2336 if (sk->sk_state == TCP_LISTEN) {
2337 ret = tcp_v4_do_rcv(sk, skb);
2338 goto put_and_return;
2339 }
2340
2341 sk_incoming_cpu_update(sk);
2342
2343 bh_lock_sock_nested(sk);
2344 tcp_segs_in(tcp_sk(sk), skb);
2345 ret = 0;
2346 if (!sock_owned_by_user(sk)) {
2347 ret = tcp_v4_do_rcv(sk, skb);
2348 } else {
2349 if (tcp_add_backlog(sk, skb, &drop_reason))
2350 goto discard_and_relse;
2351 }
2352 bh_unlock_sock(sk);
2353
2354put_and_return:
2355 if (refcounted)
2356 sock_put(sk);
2357
2358 return ret;
2359
2360no_tcp_socket:
2361 drop_reason = SKB_DROP_REASON_NO_SOCKET;
2362 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
2363 goto discard_it;
2364
2365 tcp_v4_fill_cb(skb, iph, th);
2366
2367 if (tcp_checksum_complete(skb)) {
2368csum_error:
2369 drop_reason = SKB_DROP_REASON_TCP_CSUM;
2370 trace_tcp_bad_csum(skb);
2371 __TCP_INC_STATS(net, TCP_MIB_CSUMERRORS);
2372bad_packet:
2373 __TCP_INC_STATS(net, TCP_MIB_INERRS);
2374 } else {
2375 tcp_v4_send_reset(NULL, skb);
2376 }
2377
2378discard_it:
2379 SKB_DR_OR(drop_reason, NOT_SPECIFIED);
2380 /* Discard frame. */
2381 kfree_skb_reason(skb, drop_reason);
2382 return 0;
2383
2384discard_and_relse:
2385 sk_drops_add(sk, skb);
2386 if (refcounted)
2387 sock_put(sk);
2388 goto discard_it;
2389
2390do_time_wait:
2391 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
2392 drop_reason = SKB_DROP_REASON_XFRM_POLICY;
2393 inet_twsk_put(inet_twsk(sk));
2394 goto discard_it;
2395 }
2396
2397 tcp_v4_fill_cb(skb, iph, th);
2398
2399 if (tcp_checksum_complete(skb)) {
2400 inet_twsk_put(inet_twsk(sk));
2401 goto csum_error;
2402 }
2403 switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) {
2404 case TCP_TW_SYN: {
2405 struct sock *sk2 = inet_lookup_listener(net,
2406 net->ipv4.tcp_death_row.hashinfo,
2407 skb, __tcp_hdrlen(th),
2408 iph->saddr, th->source,
2409 iph->daddr, th->dest,
2410 inet_iif(skb),
2411 sdif);
2412 if (sk2) {
2413 inet_twsk_deschedule_put(inet_twsk(sk));
2414 sk = sk2;
2415 tcp_v4_restore_cb(skb);
2416 refcounted = false;
2417 goto process;
2418 }
2419 }
2420 /* to ACK */
2421 fallthrough;
2422 case TCP_TW_ACK:
2423 tcp_v4_timewait_ack(sk, skb);
2424 break;
2425 case TCP_TW_RST:
2426 tcp_v4_send_reset(sk, skb);
2427 inet_twsk_deschedule_put(inet_twsk(sk));
2428 goto discard_it;
2429 case TCP_TW_SUCCESS:;
2430 }
2431 goto discard_it;
2432}
2433
2434static struct timewait_sock_ops tcp_timewait_sock_ops = {
2435 .twsk_obj_size = sizeof(struct tcp_timewait_sock),
2436 .twsk_unique = tcp_twsk_unique,
2437 .twsk_destructor= tcp_twsk_destructor,
2438};
2439
2440void inet_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb)
2441{
2442 struct dst_entry *dst = skb_dst(skb);
2443
2444 if (dst && dst_hold_safe(dst)) {
2445 rcu_assign_pointer(sk->sk_rx_dst, dst);
2446 sk->sk_rx_dst_ifindex = skb->skb_iif;
2447 }
2448}
2449EXPORT_SYMBOL(inet_sk_rx_dst_set);
2450
2451const struct inet_connection_sock_af_ops ipv4_specific = {
2452 .queue_xmit = ip_queue_xmit,
2453 .send_check = tcp_v4_send_check,
2454 .rebuild_header = inet_sk_rebuild_header,
2455 .sk_rx_dst_set = inet_sk_rx_dst_set,
2456 .conn_request = tcp_v4_conn_request,
2457 .syn_recv_sock = tcp_v4_syn_recv_sock,
2458 .net_header_len = sizeof(struct iphdr),
2459 .setsockopt = ip_setsockopt,
2460 .getsockopt = ip_getsockopt,
2461 .addr2sockaddr = inet_csk_addr2sockaddr,
2462 .sockaddr_len = sizeof(struct sockaddr_in),
2463 .mtu_reduced = tcp_v4_mtu_reduced,
2464};
2465EXPORT_SYMBOL(ipv4_specific);
2466
2467#if defined(CONFIG_TCP_MD5SIG) || defined(CONFIG_TCP_AO)
2468static const struct tcp_sock_af_ops tcp_sock_ipv4_specific = {
2469#ifdef CONFIG_TCP_MD5SIG
2470 .md5_lookup = tcp_v4_md5_lookup,
2471 .calc_md5_hash = tcp_v4_md5_hash_skb,
2472 .md5_parse = tcp_v4_parse_md5_keys,
2473#endif
2474#ifdef CONFIG_TCP_AO
2475 .ao_lookup = tcp_v4_ao_lookup,
2476 .calc_ao_hash = tcp_v4_ao_hash_skb,
2477 .ao_parse = tcp_v4_parse_ao,
2478 .ao_calc_key_sk = tcp_v4_ao_calc_key_sk,
2479#endif
2480};
2481#endif
2482
2483/* NOTE: A lot of things set to zero explicitly by call to
2484 * sk_alloc() so need not be done here.
2485 */
2486static int tcp_v4_init_sock(struct sock *sk)
2487{
2488 struct inet_connection_sock *icsk = inet_csk(sk);
2489
2490 tcp_init_sock(sk);
2491
2492 icsk->icsk_af_ops = &ipv4_specific;
2493
2494#if defined(CONFIG_TCP_MD5SIG) || defined(CONFIG_TCP_AO)
2495 tcp_sk(sk)->af_specific = &tcp_sock_ipv4_specific;
2496#endif
2497
2498 return 0;
2499}
2500
2501#ifdef CONFIG_TCP_MD5SIG
2502static void tcp_md5sig_info_free_rcu(struct rcu_head *head)
2503{
2504 struct tcp_md5sig_info *md5sig;
2505
2506 md5sig = container_of(head, struct tcp_md5sig_info, rcu);
2507 kfree(md5sig);
2508 static_branch_slow_dec_deferred(&tcp_md5_needed);
2509 tcp_md5_release_sigpool();
2510}
2511#endif
2512
2513void tcp_v4_destroy_sock(struct sock *sk)
2514{
2515 struct tcp_sock *tp = tcp_sk(sk);
2516
2517 trace_tcp_destroy_sock(sk);
2518
2519 tcp_clear_xmit_timers(sk);
2520
2521 tcp_cleanup_congestion_control(sk);
2522
2523 tcp_cleanup_ulp(sk);
2524
2525 /* Cleanup up the write buffer. */
2526 tcp_write_queue_purge(sk);
2527
2528 /* Check if we want to disable active TFO */
2529 tcp_fastopen_active_disable_ofo_check(sk);
2530
2531 /* Cleans up our, hopefully empty, out_of_order_queue. */
2532 skb_rbtree_purge(&tp->out_of_order_queue);
2533
2534#ifdef CONFIG_TCP_MD5SIG
2535 /* Clean up the MD5 key list, if any */
2536 if (tp->md5sig_info) {
2537 struct tcp_md5sig_info *md5sig;
2538
2539 md5sig = rcu_dereference_protected(tp->md5sig_info, 1);
2540 tcp_clear_md5_list(sk);
2541 call_rcu(&md5sig->rcu, tcp_md5sig_info_free_rcu);
2542 rcu_assign_pointer(tp->md5sig_info, NULL);
2543 }
2544#endif
2545 tcp_ao_destroy_sock(sk, false);
2546
2547 /* Clean up a referenced TCP bind bucket. */
2548 if (inet_csk(sk)->icsk_bind_hash)
2549 inet_put_port(sk);
2550
2551 BUG_ON(rcu_access_pointer(tp->fastopen_rsk));
2552
2553 /* If socket is aborted during connect operation */
2554 tcp_free_fastopen_req(tp);
2555 tcp_fastopen_destroy_cipher(sk);
2556 tcp_saved_syn_free(tp);
2557
2558 sk_sockets_allocated_dec(sk);
2559}
2560EXPORT_SYMBOL(tcp_v4_destroy_sock);
2561
2562#ifdef CONFIG_PROC_FS
2563/* Proc filesystem TCP sock list dumping. */
2564
2565static unsigned short seq_file_family(const struct seq_file *seq);
2566
2567static bool seq_sk_match(struct seq_file *seq, const struct sock *sk)
2568{
2569 unsigned short family = seq_file_family(seq);
2570
2571 /* AF_UNSPEC is used as a match all */
2572 return ((family == AF_UNSPEC || family == sk->sk_family) &&
2573 net_eq(sock_net(sk), seq_file_net(seq)));
2574}
2575
2576/* Find a non empty bucket (starting from st->bucket)
2577 * and return the first sk from it.
2578 */
2579static void *listening_get_first(struct seq_file *seq)
2580{
2581 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo;
2582 struct tcp_iter_state *st = seq->private;
2583
2584 st->offset = 0;
2585 for (; st->bucket <= hinfo->lhash2_mask; st->bucket++) {
2586 struct inet_listen_hashbucket *ilb2;
2587 struct hlist_nulls_node *node;
2588 struct sock *sk;
2589
2590 ilb2 = &hinfo->lhash2[st->bucket];
2591 if (hlist_nulls_empty(&ilb2->nulls_head))
2592 continue;
2593
2594 spin_lock(&ilb2->lock);
2595 sk_nulls_for_each(sk, node, &ilb2->nulls_head) {
2596 if (seq_sk_match(seq, sk))
2597 return sk;
2598 }
2599 spin_unlock(&ilb2->lock);
2600 }
2601
2602 return NULL;
2603}
2604
2605/* Find the next sk of "cur" within the same bucket (i.e. st->bucket).
2606 * If "cur" is the last one in the st->bucket,
2607 * call listening_get_first() to return the first sk of the next
2608 * non empty bucket.
2609 */
2610static void *listening_get_next(struct seq_file *seq, void *cur)
2611{
2612 struct tcp_iter_state *st = seq->private;
2613 struct inet_listen_hashbucket *ilb2;
2614 struct hlist_nulls_node *node;
2615 struct inet_hashinfo *hinfo;
2616 struct sock *sk = cur;
2617
2618 ++st->num;
2619 ++st->offset;
2620
2621 sk = sk_nulls_next(sk);
2622 sk_nulls_for_each_from(sk, node) {
2623 if (seq_sk_match(seq, sk))
2624 return sk;
2625 }
2626
2627 hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo;
2628 ilb2 = &hinfo->lhash2[st->bucket];
2629 spin_unlock(&ilb2->lock);
2630 ++st->bucket;
2631 return listening_get_first(seq);
2632}
2633
2634static void *listening_get_idx(struct seq_file *seq, loff_t *pos)
2635{
2636 struct tcp_iter_state *st = seq->private;
2637 void *rc;
2638
2639 st->bucket = 0;
2640 st->offset = 0;
2641 rc = listening_get_first(seq);
2642
2643 while (rc && *pos) {
2644 rc = listening_get_next(seq, rc);
2645 --*pos;
2646 }
2647 return rc;
2648}
2649
2650static inline bool empty_bucket(struct inet_hashinfo *hinfo,
2651 const struct tcp_iter_state *st)
2652{
2653 return hlist_nulls_empty(&hinfo->ehash[st->bucket].chain);
2654}
2655
2656/*
2657 * Get first established socket starting from bucket given in st->bucket.
2658 * If st->bucket is zero, the very first socket in the hash is returned.
2659 */
2660static void *established_get_first(struct seq_file *seq)
2661{
2662 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo;
2663 struct tcp_iter_state *st = seq->private;
2664
2665 st->offset = 0;
2666 for (; st->bucket <= hinfo->ehash_mask; ++st->bucket) {
2667 struct sock *sk;
2668 struct hlist_nulls_node *node;
2669 spinlock_t *lock = inet_ehash_lockp(hinfo, st->bucket);
2670
2671 cond_resched();
2672
2673 /* Lockless fast path for the common case of empty buckets */
2674 if (empty_bucket(hinfo, st))
2675 continue;
2676
2677 spin_lock_bh(lock);
2678 sk_nulls_for_each(sk, node, &hinfo->ehash[st->bucket].chain) {
2679 if (seq_sk_match(seq, sk))
2680 return sk;
2681 }
2682 spin_unlock_bh(lock);
2683 }
2684
2685 return NULL;
2686}
2687
2688static void *established_get_next(struct seq_file *seq, void *cur)
2689{
2690 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo;
2691 struct tcp_iter_state *st = seq->private;
2692 struct hlist_nulls_node *node;
2693 struct sock *sk = cur;
2694
2695 ++st->num;
2696 ++st->offset;
2697
2698 sk = sk_nulls_next(sk);
2699
2700 sk_nulls_for_each_from(sk, node) {
2701 if (seq_sk_match(seq, sk))
2702 return sk;
2703 }
2704
2705 spin_unlock_bh(inet_ehash_lockp(hinfo, st->bucket));
2706 ++st->bucket;
2707 return established_get_first(seq);
2708}
2709
2710static void *established_get_idx(struct seq_file *seq, loff_t pos)
2711{
2712 struct tcp_iter_state *st = seq->private;
2713 void *rc;
2714
2715 st->bucket = 0;
2716 rc = established_get_first(seq);
2717
2718 while (rc && pos) {
2719 rc = established_get_next(seq, rc);
2720 --pos;
2721 }
2722 return rc;
2723}
2724
2725static void *tcp_get_idx(struct seq_file *seq, loff_t pos)
2726{
2727 void *rc;
2728 struct tcp_iter_state *st = seq->private;
2729
2730 st->state = TCP_SEQ_STATE_LISTENING;
2731 rc = listening_get_idx(seq, &pos);
2732
2733 if (!rc) {
2734 st->state = TCP_SEQ_STATE_ESTABLISHED;
2735 rc = established_get_idx(seq, pos);
2736 }
2737
2738 return rc;
2739}
2740
2741static void *tcp_seek_last_pos(struct seq_file *seq)
2742{
2743 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo;
2744 struct tcp_iter_state *st = seq->private;
2745 int bucket = st->bucket;
2746 int offset = st->offset;
2747 int orig_num = st->num;
2748 void *rc = NULL;
2749
2750 switch (st->state) {
2751 case TCP_SEQ_STATE_LISTENING:
2752 if (st->bucket > hinfo->lhash2_mask)
2753 break;
2754 rc = listening_get_first(seq);
2755 while (offset-- && rc && bucket == st->bucket)
2756 rc = listening_get_next(seq, rc);
2757 if (rc)
2758 break;
2759 st->bucket = 0;
2760 st->state = TCP_SEQ_STATE_ESTABLISHED;
2761 fallthrough;
2762 case TCP_SEQ_STATE_ESTABLISHED:
2763 if (st->bucket > hinfo->ehash_mask)
2764 break;
2765 rc = established_get_first(seq);
2766 while (offset-- && rc && bucket == st->bucket)
2767 rc = established_get_next(seq, rc);
2768 }
2769
2770 st->num = orig_num;
2771
2772 return rc;
2773}
2774
2775void *tcp_seq_start(struct seq_file *seq, loff_t *pos)
2776{
2777 struct tcp_iter_state *st = seq->private;
2778 void *rc;
2779
2780 if (*pos && *pos == st->last_pos) {
2781 rc = tcp_seek_last_pos(seq);
2782 if (rc)
2783 goto out;
2784 }
2785
2786 st->state = TCP_SEQ_STATE_LISTENING;
2787 st->num = 0;
2788 st->bucket = 0;
2789 st->offset = 0;
2790 rc = *pos ? tcp_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
2791
2792out:
2793 st->last_pos = *pos;
2794 return rc;
2795}
2796EXPORT_SYMBOL(tcp_seq_start);
2797
2798void *tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2799{
2800 struct tcp_iter_state *st = seq->private;
2801 void *rc = NULL;
2802
2803 if (v == SEQ_START_TOKEN) {
2804 rc = tcp_get_idx(seq, 0);
2805 goto out;
2806 }
2807
2808 switch (st->state) {
2809 case TCP_SEQ_STATE_LISTENING:
2810 rc = listening_get_next(seq, v);
2811 if (!rc) {
2812 st->state = TCP_SEQ_STATE_ESTABLISHED;
2813 st->bucket = 0;
2814 st->offset = 0;
2815 rc = established_get_first(seq);
2816 }
2817 break;
2818 case TCP_SEQ_STATE_ESTABLISHED:
2819 rc = established_get_next(seq, v);
2820 break;
2821 }
2822out:
2823 ++*pos;
2824 st->last_pos = *pos;
2825 return rc;
2826}
2827EXPORT_SYMBOL(tcp_seq_next);
2828
2829void tcp_seq_stop(struct seq_file *seq, void *v)
2830{
2831 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo;
2832 struct tcp_iter_state *st = seq->private;
2833
2834 switch (st->state) {
2835 case TCP_SEQ_STATE_LISTENING:
2836 if (v != SEQ_START_TOKEN)
2837 spin_unlock(&hinfo->lhash2[st->bucket].lock);
2838 break;
2839 case TCP_SEQ_STATE_ESTABLISHED:
2840 if (v)
2841 spin_unlock_bh(inet_ehash_lockp(hinfo, st->bucket));
2842 break;
2843 }
2844}
2845EXPORT_SYMBOL(tcp_seq_stop);
2846
2847static void get_openreq4(const struct request_sock *req,
2848 struct seq_file *f, int i)
2849{
2850 const struct inet_request_sock *ireq = inet_rsk(req);
2851 long delta = req->rsk_timer.expires - jiffies;
2852
2853 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2854 " %02X %08X:%08X %02X:%08lX %08X %5u %8d %u %d %pK",
2855 i,
2856 ireq->ir_loc_addr,
2857 ireq->ir_num,
2858 ireq->ir_rmt_addr,
2859 ntohs(ireq->ir_rmt_port),
2860 TCP_SYN_RECV,
2861 0, 0, /* could print option size, but that is af dependent. */
2862 1, /* timers active (only the expire timer) */
2863 jiffies_delta_to_clock_t(delta),
2864 req->num_timeout,
2865 from_kuid_munged(seq_user_ns(f),
2866 sock_i_uid(req->rsk_listener)),
2867 0, /* non standard timer */
2868 0, /* open_requests have no inode */
2869 0,
2870 req);
2871}
2872
2873static void get_tcp4_sock(struct sock *sk, struct seq_file *f, int i)
2874{
2875 int timer_active;
2876 unsigned long timer_expires;
2877 const struct tcp_sock *tp = tcp_sk(sk);
2878 const struct inet_connection_sock *icsk = inet_csk(sk);
2879 const struct inet_sock *inet = inet_sk(sk);
2880 const struct fastopen_queue *fastopenq = &icsk->icsk_accept_queue.fastopenq;
2881 __be32 dest = inet->inet_daddr;
2882 __be32 src = inet->inet_rcv_saddr;
2883 __u16 destp = ntohs(inet->inet_dport);
2884 __u16 srcp = ntohs(inet->inet_sport);
2885 int rx_queue;
2886 int state;
2887
2888 if (icsk->icsk_pending == ICSK_TIME_RETRANS ||
2889 icsk->icsk_pending == ICSK_TIME_REO_TIMEOUT ||
2890 icsk->icsk_pending == ICSK_TIME_LOSS_PROBE) {
2891 timer_active = 1;
2892 timer_expires = icsk->icsk_timeout;
2893 } else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
2894 timer_active = 4;
2895 timer_expires = icsk->icsk_timeout;
2896 } else if (timer_pending(&sk->sk_timer)) {
2897 timer_active = 2;
2898 timer_expires = sk->sk_timer.expires;
2899 } else {
2900 timer_active = 0;
2901 timer_expires = jiffies;
2902 }
2903
2904 state = inet_sk_state_load(sk);
2905 if (state == TCP_LISTEN)
2906 rx_queue = READ_ONCE(sk->sk_ack_backlog);
2907 else
2908 /* Because we don't lock the socket,
2909 * we might find a transient negative value.
2910 */
2911 rx_queue = max_t(int, READ_ONCE(tp->rcv_nxt) -
2912 READ_ONCE(tp->copied_seq), 0);
2913
2914 seq_printf(f, "%4d: %08X:%04X %08X:%04X %02X %08X:%08X %02X:%08lX "
2915 "%08X %5u %8d %lu %d %pK %lu %lu %u %u %d",
2916 i, src, srcp, dest, destp, state,
2917 READ_ONCE(tp->write_seq) - tp->snd_una,
2918 rx_queue,
2919 timer_active,
2920 jiffies_delta_to_clock_t(timer_expires - jiffies),
2921 icsk->icsk_retransmits,
2922 from_kuid_munged(seq_user_ns(f), sock_i_uid(sk)),
2923 icsk->icsk_probes_out,
2924 sock_i_ino(sk),
2925 refcount_read(&sk->sk_refcnt), sk,
2926 jiffies_to_clock_t(icsk->icsk_rto),
2927 jiffies_to_clock_t(icsk->icsk_ack.ato),
2928 (icsk->icsk_ack.quick << 1) | inet_csk_in_pingpong_mode(sk),
2929 tcp_snd_cwnd(tp),
2930 state == TCP_LISTEN ?
2931 fastopenq->max_qlen :
2932 (tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh));
2933}
2934
2935static void get_timewait4_sock(const struct inet_timewait_sock *tw,
2936 struct seq_file *f, int i)
2937{
2938 long delta = tw->tw_timer.expires - jiffies;
2939 __be32 dest, src;
2940 __u16 destp, srcp;
2941
2942 dest = tw->tw_daddr;
2943 src = tw->tw_rcv_saddr;
2944 destp = ntohs(tw->tw_dport);
2945 srcp = ntohs(tw->tw_sport);
2946
2947 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2948 " %02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK",
2949 i, src, srcp, dest, destp, tw->tw_substate, 0, 0,
2950 3, jiffies_delta_to_clock_t(delta), 0, 0, 0, 0,
2951 refcount_read(&tw->tw_refcnt), tw);
2952}
2953
2954#define TMPSZ 150
2955
2956static int tcp4_seq_show(struct seq_file *seq, void *v)
2957{
2958 struct tcp_iter_state *st;
2959 struct sock *sk = v;
2960
2961 seq_setwidth(seq, TMPSZ - 1);
2962 if (v == SEQ_START_TOKEN) {
2963 seq_puts(seq, " sl local_address rem_address st tx_queue "
2964 "rx_queue tr tm->when retrnsmt uid timeout "
2965 "inode");
2966 goto out;
2967 }
2968 st = seq->private;
2969
2970 if (sk->sk_state == TCP_TIME_WAIT)
2971 get_timewait4_sock(v, seq, st->num);
2972 else if (sk->sk_state == TCP_NEW_SYN_RECV)
2973 get_openreq4(v, seq, st->num);
2974 else
2975 get_tcp4_sock(v, seq, st->num);
2976out:
2977 seq_pad(seq, '\n');
2978 return 0;
2979}
2980
2981#ifdef CONFIG_BPF_SYSCALL
2982struct bpf_tcp_iter_state {
2983 struct tcp_iter_state state;
2984 unsigned int cur_sk;
2985 unsigned int end_sk;
2986 unsigned int max_sk;
2987 struct sock **batch;
2988 bool st_bucket_done;
2989};
2990
2991struct bpf_iter__tcp {
2992 __bpf_md_ptr(struct bpf_iter_meta *, meta);
2993 __bpf_md_ptr(struct sock_common *, sk_common);
2994 uid_t uid __aligned(8);
2995};
2996
2997static int tcp_prog_seq_show(struct bpf_prog *prog, struct bpf_iter_meta *meta,
2998 struct sock_common *sk_common, uid_t uid)
2999{
3000 struct bpf_iter__tcp ctx;
3001
3002 meta->seq_num--; /* skip SEQ_START_TOKEN */
3003 ctx.meta = meta;
3004 ctx.sk_common = sk_common;
3005 ctx.uid = uid;
3006 return bpf_iter_run_prog(prog, &ctx);
3007}
3008
3009static void bpf_iter_tcp_put_batch(struct bpf_tcp_iter_state *iter)
3010{
3011 while (iter->cur_sk < iter->end_sk)
3012 sock_gen_put(iter->batch[iter->cur_sk++]);
3013}
3014
3015static int bpf_iter_tcp_realloc_batch(struct bpf_tcp_iter_state *iter,
3016 unsigned int new_batch_sz)
3017{
3018 struct sock **new_batch;
3019
3020 new_batch = kvmalloc(sizeof(*new_batch) * new_batch_sz,
3021 GFP_USER | __GFP_NOWARN);
3022 if (!new_batch)
3023 return -ENOMEM;
3024
3025 bpf_iter_tcp_put_batch(iter);
3026 kvfree(iter->batch);
3027 iter->batch = new_batch;
3028 iter->max_sk = new_batch_sz;
3029
3030 return 0;
3031}
3032
3033static unsigned int bpf_iter_tcp_listening_batch(struct seq_file *seq,
3034 struct sock *start_sk)
3035{
3036 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo;
3037 struct bpf_tcp_iter_state *iter = seq->private;
3038 struct tcp_iter_state *st = &iter->state;
3039 struct hlist_nulls_node *node;
3040 unsigned int expected = 1;
3041 struct sock *sk;
3042
3043 sock_hold(start_sk);
3044 iter->batch[iter->end_sk++] = start_sk;
3045
3046 sk = sk_nulls_next(start_sk);
3047 sk_nulls_for_each_from(sk, node) {
3048 if (seq_sk_match(seq, sk)) {
3049 if (iter->end_sk < iter->max_sk) {
3050 sock_hold(sk);
3051 iter->batch[iter->end_sk++] = sk;
3052 }
3053 expected++;
3054 }
3055 }
3056 spin_unlock(&hinfo->lhash2[st->bucket].lock);
3057
3058 return expected;
3059}
3060
3061static unsigned int bpf_iter_tcp_established_batch(struct seq_file *seq,
3062 struct sock *start_sk)
3063{
3064 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo;
3065 struct bpf_tcp_iter_state *iter = seq->private;
3066 struct tcp_iter_state *st = &iter->state;
3067 struct hlist_nulls_node *node;
3068 unsigned int expected = 1;
3069 struct sock *sk;
3070
3071 sock_hold(start_sk);
3072 iter->batch[iter->end_sk++] = start_sk;
3073
3074 sk = sk_nulls_next(start_sk);
3075 sk_nulls_for_each_from(sk, node) {
3076 if (seq_sk_match(seq, sk)) {
3077 if (iter->end_sk < iter->max_sk) {
3078 sock_hold(sk);
3079 iter->batch[iter->end_sk++] = sk;
3080 }
3081 expected++;
3082 }
3083 }
3084 spin_unlock_bh(inet_ehash_lockp(hinfo, st->bucket));
3085
3086 return expected;
3087}
3088
3089static struct sock *bpf_iter_tcp_batch(struct seq_file *seq)
3090{
3091 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo;
3092 struct bpf_tcp_iter_state *iter = seq->private;
3093 struct tcp_iter_state *st = &iter->state;
3094 unsigned int expected;
3095 bool resized = false;
3096 struct sock *sk;
3097
3098 /* The st->bucket is done. Directly advance to the next
3099 * bucket instead of having the tcp_seek_last_pos() to skip
3100 * one by one in the current bucket and eventually find out
3101 * it has to advance to the next bucket.
3102 */
3103 if (iter->st_bucket_done) {
3104 st->offset = 0;
3105 st->bucket++;
3106 if (st->state == TCP_SEQ_STATE_LISTENING &&
3107 st->bucket > hinfo->lhash2_mask) {
3108 st->state = TCP_SEQ_STATE_ESTABLISHED;
3109 st->bucket = 0;
3110 }
3111 }
3112
3113again:
3114 /* Get a new batch */
3115 iter->cur_sk = 0;
3116 iter->end_sk = 0;
3117 iter->st_bucket_done = false;
3118
3119 sk = tcp_seek_last_pos(seq);
3120 if (!sk)
3121 return NULL; /* Done */
3122
3123 if (st->state == TCP_SEQ_STATE_LISTENING)
3124 expected = bpf_iter_tcp_listening_batch(seq, sk);
3125 else
3126 expected = bpf_iter_tcp_established_batch(seq, sk);
3127
3128 if (iter->end_sk == expected) {
3129 iter->st_bucket_done = true;
3130 return sk;
3131 }
3132
3133 if (!resized && !bpf_iter_tcp_realloc_batch(iter, expected * 3 / 2)) {
3134 resized = true;
3135 goto again;
3136 }
3137
3138 return sk;
3139}
3140
3141static void *bpf_iter_tcp_seq_start(struct seq_file *seq, loff_t *pos)
3142{
3143 /* bpf iter does not support lseek, so it always
3144 * continue from where it was stop()-ped.
3145 */
3146 if (*pos)
3147 return bpf_iter_tcp_batch(seq);
3148
3149 return SEQ_START_TOKEN;
3150}
3151
3152static void *bpf_iter_tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
3153{
3154 struct bpf_tcp_iter_state *iter = seq->private;
3155 struct tcp_iter_state *st = &iter->state;
3156 struct sock *sk;
3157
3158 /* Whenever seq_next() is called, the iter->cur_sk is
3159 * done with seq_show(), so advance to the next sk in
3160 * the batch.
3161 */
3162 if (iter->cur_sk < iter->end_sk) {
3163 /* Keeping st->num consistent in tcp_iter_state.
3164 * bpf_iter_tcp does not use st->num.
3165 * meta.seq_num is used instead.
3166 */
3167 st->num++;
3168 /* Move st->offset to the next sk in the bucket such that
3169 * the future start() will resume at st->offset in
3170 * st->bucket. See tcp_seek_last_pos().
3171 */
3172 st->offset++;
3173 sock_gen_put(iter->batch[iter->cur_sk++]);
3174 }
3175
3176 if (iter->cur_sk < iter->end_sk)
3177 sk = iter->batch[iter->cur_sk];
3178 else
3179 sk = bpf_iter_tcp_batch(seq);
3180
3181 ++*pos;
3182 /* Keeping st->last_pos consistent in tcp_iter_state.
3183 * bpf iter does not do lseek, so st->last_pos always equals to *pos.
3184 */
3185 st->last_pos = *pos;
3186 return sk;
3187}
3188
3189static int bpf_iter_tcp_seq_show(struct seq_file *seq, void *v)
3190{
3191 struct bpf_iter_meta meta;
3192 struct bpf_prog *prog;
3193 struct sock *sk = v;
3194 uid_t uid;
3195 int ret;
3196
3197 if (v == SEQ_START_TOKEN)
3198 return 0;
3199
3200 if (sk_fullsock(sk))
3201 lock_sock(sk);
3202
3203 if (unlikely(sk_unhashed(sk))) {
3204 ret = SEQ_SKIP;
3205 goto unlock;
3206 }
3207
3208 if (sk->sk_state == TCP_TIME_WAIT) {
3209 uid = 0;
3210 } else if (sk->sk_state == TCP_NEW_SYN_RECV) {
3211 const struct request_sock *req = v;
3212
3213 uid = from_kuid_munged(seq_user_ns(seq),
3214 sock_i_uid(req->rsk_listener));
3215 } else {
3216 uid = from_kuid_munged(seq_user_ns(seq), sock_i_uid(sk));
3217 }
3218
3219 meta.seq = seq;
3220 prog = bpf_iter_get_info(&meta, false);
3221 ret = tcp_prog_seq_show(prog, &meta, v, uid);
3222
3223unlock:
3224 if (sk_fullsock(sk))
3225 release_sock(sk);
3226 return ret;
3227
3228}
3229
3230static void bpf_iter_tcp_seq_stop(struct seq_file *seq, void *v)
3231{
3232 struct bpf_tcp_iter_state *iter = seq->private;
3233 struct bpf_iter_meta meta;
3234 struct bpf_prog *prog;
3235
3236 if (!v) {
3237 meta.seq = seq;
3238 prog = bpf_iter_get_info(&meta, true);
3239 if (prog)
3240 (void)tcp_prog_seq_show(prog, &meta, v, 0);
3241 }
3242
3243 if (iter->cur_sk < iter->end_sk) {
3244 bpf_iter_tcp_put_batch(iter);
3245 iter->st_bucket_done = false;
3246 }
3247}
3248
3249static const struct seq_operations bpf_iter_tcp_seq_ops = {
3250 .show = bpf_iter_tcp_seq_show,
3251 .start = bpf_iter_tcp_seq_start,
3252 .next = bpf_iter_tcp_seq_next,
3253 .stop = bpf_iter_tcp_seq_stop,
3254};
3255#endif
3256static unsigned short seq_file_family(const struct seq_file *seq)
3257{
3258 const struct tcp_seq_afinfo *afinfo;
3259
3260#ifdef CONFIG_BPF_SYSCALL
3261 /* Iterated from bpf_iter. Let the bpf prog to filter instead. */
3262 if (seq->op == &bpf_iter_tcp_seq_ops)
3263 return AF_UNSPEC;
3264#endif
3265
3266 /* Iterated from proc fs */
3267 afinfo = pde_data(file_inode(seq->file));
3268 return afinfo->family;
3269}
3270
3271static const struct seq_operations tcp4_seq_ops = {
3272 .show = tcp4_seq_show,
3273 .start = tcp_seq_start,
3274 .next = tcp_seq_next,
3275 .stop = tcp_seq_stop,
3276};
3277
3278static struct tcp_seq_afinfo tcp4_seq_afinfo = {
3279 .family = AF_INET,
3280};
3281
3282static int __net_init tcp4_proc_init_net(struct net *net)
3283{
3284 if (!proc_create_net_data("tcp", 0444, net->proc_net, &tcp4_seq_ops,
3285 sizeof(struct tcp_iter_state), &tcp4_seq_afinfo))
3286 return -ENOMEM;
3287 return 0;
3288}
3289
3290static void __net_exit tcp4_proc_exit_net(struct net *net)
3291{
3292 remove_proc_entry("tcp", net->proc_net);
3293}
3294
3295static struct pernet_operations tcp4_net_ops = {
3296 .init = tcp4_proc_init_net,
3297 .exit = tcp4_proc_exit_net,
3298};
3299
3300int __init tcp4_proc_init(void)
3301{
3302 return register_pernet_subsys(&tcp4_net_ops);
3303}
3304
3305void tcp4_proc_exit(void)
3306{
3307 unregister_pernet_subsys(&tcp4_net_ops);
3308}
3309#endif /* CONFIG_PROC_FS */
3310
3311/* @wake is one when sk_stream_write_space() calls us.
3312 * This sends EPOLLOUT only if notsent_bytes is half the limit.
3313 * This mimics the strategy used in sock_def_write_space().
3314 */
3315bool tcp_stream_memory_free(const struct sock *sk, int wake)
3316{
3317 const struct tcp_sock *tp = tcp_sk(sk);
3318 u32 notsent_bytes = READ_ONCE(tp->write_seq) -
3319 READ_ONCE(tp->snd_nxt);
3320
3321 return (notsent_bytes << wake) < tcp_notsent_lowat(tp);
3322}
3323EXPORT_SYMBOL(tcp_stream_memory_free);
3324
3325struct proto tcp_prot = {
3326 .name = "TCP",
3327 .owner = THIS_MODULE,
3328 .close = tcp_close,
3329 .pre_connect = tcp_v4_pre_connect,
3330 .connect = tcp_v4_connect,
3331 .disconnect = tcp_disconnect,
3332 .accept = inet_csk_accept,
3333 .ioctl = tcp_ioctl,
3334 .init = tcp_v4_init_sock,
3335 .destroy = tcp_v4_destroy_sock,
3336 .shutdown = tcp_shutdown,
3337 .setsockopt = tcp_setsockopt,
3338 .getsockopt = tcp_getsockopt,
3339 .bpf_bypass_getsockopt = tcp_bpf_bypass_getsockopt,
3340 .keepalive = tcp_set_keepalive,
3341 .recvmsg = tcp_recvmsg,
3342 .sendmsg = tcp_sendmsg,
3343 .splice_eof = tcp_splice_eof,
3344 .backlog_rcv = tcp_v4_do_rcv,
3345 .release_cb = tcp_release_cb,
3346 .hash = inet_hash,
3347 .unhash = inet_unhash,
3348 .get_port = inet_csk_get_port,
3349 .put_port = inet_put_port,
3350#ifdef CONFIG_BPF_SYSCALL
3351 .psock_update_sk_prot = tcp_bpf_update_proto,
3352#endif
3353 .enter_memory_pressure = tcp_enter_memory_pressure,
3354 .leave_memory_pressure = tcp_leave_memory_pressure,
3355 .stream_memory_free = tcp_stream_memory_free,
3356 .sockets_allocated = &tcp_sockets_allocated,
3357 .orphan_count = &tcp_orphan_count,
3358
3359 .memory_allocated = &tcp_memory_allocated,
3360 .per_cpu_fw_alloc = &tcp_memory_per_cpu_fw_alloc,
3361
3362 .memory_pressure = &tcp_memory_pressure,
3363 .sysctl_mem = sysctl_tcp_mem,
3364 .sysctl_wmem_offset = offsetof(struct net, ipv4.sysctl_tcp_wmem),
3365 .sysctl_rmem_offset = offsetof(struct net, ipv4.sysctl_tcp_rmem),
3366 .max_header = MAX_TCP_HEADER,
3367 .obj_size = sizeof(struct tcp_sock),
3368 .slab_flags = SLAB_TYPESAFE_BY_RCU,
3369 .twsk_prot = &tcp_timewait_sock_ops,
3370 .rsk_prot = &tcp_request_sock_ops,
3371 .h.hashinfo = NULL,
3372 .no_autobind = true,
3373 .diag_destroy = tcp_abort,
3374};
3375EXPORT_SYMBOL(tcp_prot);
3376
3377static void __net_exit tcp_sk_exit(struct net *net)
3378{
3379 if (net->ipv4.tcp_congestion_control)
3380 bpf_module_put(net->ipv4.tcp_congestion_control,
3381 net->ipv4.tcp_congestion_control->owner);
3382}
3383
3384static void __net_init tcp_set_hashinfo(struct net *net)
3385{
3386 struct inet_hashinfo *hinfo;
3387 unsigned int ehash_entries;
3388 struct net *old_net;
3389
3390 if (net_eq(net, &init_net))
3391 goto fallback;
3392
3393 old_net = current->nsproxy->net_ns;
3394 ehash_entries = READ_ONCE(old_net->ipv4.sysctl_tcp_child_ehash_entries);
3395 if (!ehash_entries)
3396 goto fallback;
3397
3398 ehash_entries = roundup_pow_of_two(ehash_entries);
3399 hinfo = inet_pernet_hashinfo_alloc(&tcp_hashinfo, ehash_entries);
3400 if (!hinfo) {
3401 pr_warn("Failed to allocate TCP ehash (entries: %u) "
3402 "for a netns, fallback to the global one\n",
3403 ehash_entries);
3404fallback:
3405 hinfo = &tcp_hashinfo;
3406 ehash_entries = tcp_hashinfo.ehash_mask + 1;
3407 }
3408
3409 net->ipv4.tcp_death_row.hashinfo = hinfo;
3410 net->ipv4.tcp_death_row.sysctl_max_tw_buckets = ehash_entries / 2;
3411 net->ipv4.sysctl_max_syn_backlog = max(128U, ehash_entries / 128);
3412}
3413
3414static int __net_init tcp_sk_init(struct net *net)
3415{
3416 net->ipv4.sysctl_tcp_ecn = 2;
3417 net->ipv4.sysctl_tcp_ecn_fallback = 1;
3418
3419 net->ipv4.sysctl_tcp_base_mss = TCP_BASE_MSS;
3420 net->ipv4.sysctl_tcp_min_snd_mss = TCP_MIN_SND_MSS;
3421 net->ipv4.sysctl_tcp_probe_threshold = TCP_PROBE_THRESHOLD;
3422 net->ipv4.sysctl_tcp_probe_interval = TCP_PROBE_INTERVAL;
3423 net->ipv4.sysctl_tcp_mtu_probe_floor = TCP_MIN_SND_MSS;
3424
3425 net->ipv4.sysctl_tcp_keepalive_time = TCP_KEEPALIVE_TIME;
3426 net->ipv4.sysctl_tcp_keepalive_probes = TCP_KEEPALIVE_PROBES;
3427 net->ipv4.sysctl_tcp_keepalive_intvl = TCP_KEEPALIVE_INTVL;
3428
3429 net->ipv4.sysctl_tcp_syn_retries = TCP_SYN_RETRIES;
3430 net->ipv4.sysctl_tcp_synack_retries = TCP_SYNACK_RETRIES;
3431 net->ipv4.sysctl_tcp_syncookies = 1;
3432 net->ipv4.sysctl_tcp_reordering = TCP_FASTRETRANS_THRESH;
3433 net->ipv4.sysctl_tcp_retries1 = TCP_RETR1;
3434 net->ipv4.sysctl_tcp_retries2 = TCP_RETR2;
3435 net->ipv4.sysctl_tcp_orphan_retries = 0;
3436 net->ipv4.sysctl_tcp_fin_timeout = TCP_FIN_TIMEOUT;
3437 net->ipv4.sysctl_tcp_notsent_lowat = UINT_MAX;
3438 net->ipv4.sysctl_tcp_tw_reuse = 2;
3439 net->ipv4.sysctl_tcp_no_ssthresh_metrics_save = 1;
3440
3441 refcount_set(&net->ipv4.tcp_death_row.tw_refcount, 1);
3442 tcp_set_hashinfo(net);
3443
3444 net->ipv4.sysctl_tcp_sack = 1;
3445 net->ipv4.sysctl_tcp_window_scaling = 1;
3446 net->ipv4.sysctl_tcp_timestamps = 1;
3447 net->ipv4.sysctl_tcp_early_retrans = 3;
3448 net->ipv4.sysctl_tcp_recovery = TCP_RACK_LOSS_DETECTION;
3449 net->ipv4.sysctl_tcp_slow_start_after_idle = 1; /* By default, RFC2861 behavior. */
3450 net->ipv4.sysctl_tcp_retrans_collapse = 1;
3451 net->ipv4.sysctl_tcp_max_reordering = 300;
3452 net->ipv4.sysctl_tcp_dsack = 1;
3453 net->ipv4.sysctl_tcp_app_win = 31;
3454 net->ipv4.sysctl_tcp_adv_win_scale = 1;
3455 net->ipv4.sysctl_tcp_frto = 2;
3456 net->ipv4.sysctl_tcp_moderate_rcvbuf = 1;
3457 /* This limits the percentage of the congestion window which we
3458 * will allow a single TSO frame to consume. Building TSO frames
3459 * which are too large can cause TCP streams to be bursty.
3460 */
3461 net->ipv4.sysctl_tcp_tso_win_divisor = 3;
3462 /* Default TSQ limit of 16 TSO segments */
3463 net->ipv4.sysctl_tcp_limit_output_bytes = 16 * 65536;
3464
3465 /* rfc5961 challenge ack rate limiting, per net-ns, disabled by default. */
3466 net->ipv4.sysctl_tcp_challenge_ack_limit = INT_MAX;
3467
3468 net->ipv4.sysctl_tcp_min_tso_segs = 2;
3469 net->ipv4.sysctl_tcp_tso_rtt_log = 9; /* 2^9 = 512 usec */
3470 net->ipv4.sysctl_tcp_min_rtt_wlen = 300;
3471 net->ipv4.sysctl_tcp_autocorking = 1;
3472 net->ipv4.sysctl_tcp_invalid_ratelimit = HZ/2;
3473 net->ipv4.sysctl_tcp_pacing_ss_ratio = 200;
3474 net->ipv4.sysctl_tcp_pacing_ca_ratio = 120;
3475 if (net != &init_net) {
3476 memcpy(net->ipv4.sysctl_tcp_rmem,
3477 init_net.ipv4.sysctl_tcp_rmem,
3478 sizeof(init_net.ipv4.sysctl_tcp_rmem));
3479 memcpy(net->ipv4.sysctl_tcp_wmem,
3480 init_net.ipv4.sysctl_tcp_wmem,
3481 sizeof(init_net.ipv4.sysctl_tcp_wmem));
3482 }
3483 net->ipv4.sysctl_tcp_comp_sack_delay_ns = NSEC_PER_MSEC;
3484 net->ipv4.sysctl_tcp_comp_sack_slack_ns = 100 * NSEC_PER_USEC;
3485 net->ipv4.sysctl_tcp_comp_sack_nr = 44;
3486 net->ipv4.sysctl_tcp_backlog_ack_defer = 1;
3487 net->ipv4.sysctl_tcp_fastopen = TFO_CLIENT_ENABLE;
3488 net->ipv4.sysctl_tcp_fastopen_blackhole_timeout = 0;
3489 atomic_set(&net->ipv4.tfo_active_disable_times, 0);
3490
3491 /* Set default values for PLB */
3492 net->ipv4.sysctl_tcp_plb_enabled = 0; /* Disabled by default */
3493 net->ipv4.sysctl_tcp_plb_idle_rehash_rounds = 3;
3494 net->ipv4.sysctl_tcp_plb_rehash_rounds = 12;
3495 net->ipv4.sysctl_tcp_plb_suspend_rto_sec = 60;
3496 /* Default congestion threshold for PLB to mark a round is 50% */
3497 net->ipv4.sysctl_tcp_plb_cong_thresh = (1 << TCP_PLB_SCALE) / 2;
3498
3499 /* Reno is always built in */
3500 if (!net_eq(net, &init_net) &&
3501 bpf_try_module_get(init_net.ipv4.tcp_congestion_control,
3502 init_net.ipv4.tcp_congestion_control->owner))
3503 net->ipv4.tcp_congestion_control = init_net.ipv4.tcp_congestion_control;
3504 else
3505 net->ipv4.tcp_congestion_control = &tcp_reno;
3506
3507 net->ipv4.sysctl_tcp_syn_linear_timeouts = 4;
3508 net->ipv4.sysctl_tcp_shrink_window = 0;
3509
3510 net->ipv4.sysctl_tcp_pingpong_thresh = 1;
3511
3512 return 0;
3513}
3514
3515static void __net_exit tcp_sk_exit_batch(struct list_head *net_exit_list)
3516{
3517 struct net *net;
3518
3519 tcp_twsk_purge(net_exit_list, AF_INET);
3520
3521 list_for_each_entry(net, net_exit_list, exit_list) {
3522 inet_pernet_hashinfo_free(net->ipv4.tcp_death_row.hashinfo);
3523 WARN_ON_ONCE(!refcount_dec_and_test(&net->ipv4.tcp_death_row.tw_refcount));
3524 tcp_fastopen_ctx_destroy(net);
3525 }
3526}
3527
3528static struct pernet_operations __net_initdata tcp_sk_ops = {
3529 .init = tcp_sk_init,
3530 .exit = tcp_sk_exit,
3531 .exit_batch = tcp_sk_exit_batch,
3532};
3533
3534#if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS)
3535DEFINE_BPF_ITER_FUNC(tcp, struct bpf_iter_meta *meta,
3536 struct sock_common *sk_common, uid_t uid)
3537
3538#define INIT_BATCH_SZ 16
3539
3540static int bpf_iter_init_tcp(void *priv_data, struct bpf_iter_aux_info *aux)
3541{
3542 struct bpf_tcp_iter_state *iter = priv_data;
3543 int err;
3544
3545 err = bpf_iter_init_seq_net(priv_data, aux);
3546 if (err)
3547 return err;
3548
3549 err = bpf_iter_tcp_realloc_batch(iter, INIT_BATCH_SZ);
3550 if (err) {
3551 bpf_iter_fini_seq_net(priv_data);
3552 return err;
3553 }
3554
3555 return 0;
3556}
3557
3558static void bpf_iter_fini_tcp(void *priv_data)
3559{
3560 struct bpf_tcp_iter_state *iter = priv_data;
3561
3562 bpf_iter_fini_seq_net(priv_data);
3563 kvfree(iter->batch);
3564}
3565
3566static const struct bpf_iter_seq_info tcp_seq_info = {
3567 .seq_ops = &bpf_iter_tcp_seq_ops,
3568 .init_seq_private = bpf_iter_init_tcp,
3569 .fini_seq_private = bpf_iter_fini_tcp,
3570 .seq_priv_size = sizeof(struct bpf_tcp_iter_state),
3571};
3572
3573static const struct bpf_func_proto *
3574bpf_iter_tcp_get_func_proto(enum bpf_func_id func_id,
3575 const struct bpf_prog *prog)
3576{
3577 switch (func_id) {
3578 case BPF_FUNC_setsockopt:
3579 return &bpf_sk_setsockopt_proto;
3580 case BPF_FUNC_getsockopt:
3581 return &bpf_sk_getsockopt_proto;
3582 default:
3583 return NULL;
3584 }
3585}
3586
3587static struct bpf_iter_reg tcp_reg_info = {
3588 .target = "tcp",
3589 .ctx_arg_info_size = 1,
3590 .ctx_arg_info = {
3591 { offsetof(struct bpf_iter__tcp, sk_common),
3592 PTR_TO_BTF_ID_OR_NULL | PTR_TRUSTED },
3593 },
3594 .get_func_proto = bpf_iter_tcp_get_func_proto,
3595 .seq_info = &tcp_seq_info,
3596};
3597
3598static void __init bpf_iter_register(void)
3599{
3600 tcp_reg_info.ctx_arg_info[0].btf_id = btf_sock_ids[BTF_SOCK_TYPE_SOCK_COMMON];
3601 if (bpf_iter_reg_target(&tcp_reg_info))
3602 pr_warn("Warning: could not register bpf iterator tcp\n");
3603}
3604
3605#endif
3606
3607void __init tcp_v4_init(void)
3608{
3609 int cpu, res;
3610
3611 for_each_possible_cpu(cpu) {
3612 struct sock *sk;
3613
3614 res = inet_ctl_sock_create(&sk, PF_INET, SOCK_RAW,
3615 IPPROTO_TCP, &init_net);
3616 if (res)
3617 panic("Failed to create the TCP control socket.\n");
3618 sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
3619
3620 /* Please enforce IP_DF and IPID==0 for RST and
3621 * ACK sent in SYN-RECV and TIME-WAIT state.
3622 */
3623 inet_sk(sk)->pmtudisc = IP_PMTUDISC_DO;
3624
3625 per_cpu(ipv4_tcp_sk, cpu) = sk;
3626 }
3627 if (register_pernet_subsys(&tcp_sk_ops))
3628 panic("Failed to create the TCP control socket.\n");
3629
3630#if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS)
3631 bpf_iter_register();
3632#endif
3633}