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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * INET An implementation of the TCP/IP protocol suite for the LINUX
4 * operating system. INET is implemented using the BSD Socket
5 * interface as the means of communication with the user level.
6 *
7 * Implementation of the Transmission Control Protocol(TCP).
8 *
9 * IPv4 specific functions
10 *
11 * code split from:
12 * linux/ipv4/tcp.c
13 * linux/ipv4/tcp_input.c
14 * linux/ipv4/tcp_output.c
15 *
16 * See tcp.c for author information
17 */
18
19/*
20 * Changes:
21 * David S. Miller : New socket lookup architecture.
22 * This code is dedicated to John Dyson.
23 * David S. Miller : Change semantics of established hash,
24 * half is devoted to TIME_WAIT sockets
25 * and the rest go in the other half.
26 * Andi Kleen : Add support for syncookies and fixed
27 * some bugs: ip options weren't passed to
28 * the TCP layer, missed a check for an
29 * ACK bit.
30 * Andi Kleen : Implemented fast path mtu discovery.
31 * Fixed many serious bugs in the
32 * request_sock handling and moved
33 * most of it into the af independent code.
34 * Added tail drop and some other bugfixes.
35 * Added new listen semantics.
36 * Mike McLagan : Routing by source
37 * Juan Jose Ciarlante: ip_dynaddr bits
38 * Andi Kleen: various fixes.
39 * Vitaly E. Lavrov : Transparent proxy revived after year
40 * coma.
41 * Andi Kleen : Fix new listen.
42 * Andi Kleen : Fix accept error reporting.
43 * YOSHIFUJI Hideaki @USAGI and: Support IPV6_V6ONLY socket option, which
44 * Alexey Kuznetsov allow both IPv4 and IPv6 sockets to bind
45 * a single port at the same time.
46 */
47
48#define pr_fmt(fmt) "TCP: " fmt
49
50#include <linux/bottom_half.h>
51#include <linux/types.h>
52#include <linux/fcntl.h>
53#include <linux/module.h>
54#include <linux/random.h>
55#include <linux/cache.h>
56#include <linux/jhash.h>
57#include <linux/init.h>
58#include <linux/times.h>
59#include <linux/slab.h>
60
61#include <net/net_namespace.h>
62#include <net/icmp.h>
63#include <net/inet_hashtables.h>
64#include <net/tcp.h>
65#include <net/transp_v6.h>
66#include <net/ipv6.h>
67#include <net/inet_common.h>
68#include <net/timewait_sock.h>
69#include <net/xfrm.h>
70#include <net/secure_seq.h>
71#include <net/busy_poll.h>
72
73#include <linux/inet.h>
74#include <linux/ipv6.h>
75#include <linux/stddef.h>
76#include <linux/proc_fs.h>
77#include <linux/seq_file.h>
78#include <linux/inetdevice.h>
79#include <linux/btf_ids.h>
80
81#include <crypto/hash.h>
82#include <linux/scatterlist.h>
83
84#include <trace/events/tcp.h>
85
86#ifdef CONFIG_TCP_MD5SIG
87static int tcp_v4_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key,
88 __be32 daddr, __be32 saddr, const struct tcphdr *th);
89#endif
90
91struct inet_hashinfo tcp_hashinfo;
92EXPORT_SYMBOL(tcp_hashinfo);
93
94static DEFINE_PER_CPU(struct sock *, ipv4_tcp_sk);
95
96static u32 tcp_v4_init_seq(const struct sk_buff *skb)
97{
98 return secure_tcp_seq(ip_hdr(skb)->daddr,
99 ip_hdr(skb)->saddr,
100 tcp_hdr(skb)->dest,
101 tcp_hdr(skb)->source);
102}
103
104static u32 tcp_v4_init_ts_off(const struct net *net, const struct sk_buff *skb)
105{
106 return secure_tcp_ts_off(net, ip_hdr(skb)->daddr, ip_hdr(skb)->saddr);
107}
108
109int tcp_twsk_unique(struct sock *sk, struct sock *sktw, void *twp)
110{
111 int reuse = READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_tw_reuse);
112 const struct inet_timewait_sock *tw = inet_twsk(sktw);
113 const struct tcp_timewait_sock *tcptw = tcp_twsk(sktw);
114 struct tcp_sock *tp = tcp_sk(sk);
115
116 if (reuse == 2) {
117 /* Still does not detect *everything* that goes through
118 * lo, since we require a loopback src or dst address
119 * or direct binding to 'lo' interface.
120 */
121 bool loopback = false;
122 if (tw->tw_bound_dev_if == LOOPBACK_IFINDEX)
123 loopback = true;
124#if IS_ENABLED(CONFIG_IPV6)
125 if (tw->tw_family == AF_INET6) {
126 if (ipv6_addr_loopback(&tw->tw_v6_daddr) ||
127 ipv6_addr_v4mapped_loopback(&tw->tw_v6_daddr) ||
128 ipv6_addr_loopback(&tw->tw_v6_rcv_saddr) ||
129 ipv6_addr_v4mapped_loopback(&tw->tw_v6_rcv_saddr))
130 loopback = true;
131 } else
132#endif
133 {
134 if (ipv4_is_loopback(tw->tw_daddr) ||
135 ipv4_is_loopback(tw->tw_rcv_saddr))
136 loopback = true;
137 }
138 if (!loopback)
139 reuse = 0;
140 }
141
142 /* With PAWS, it is safe from the viewpoint
143 of data integrity. Even without PAWS it is safe provided sequence
144 spaces do not overlap i.e. at data rates <= 80Mbit/sec.
145
146 Actually, the idea is close to VJ's one, only timestamp cache is
147 held not per host, but per port pair and TW bucket is used as state
148 holder.
149
150 If TW bucket has been already destroyed we fall back to VJ's scheme
151 and use initial timestamp retrieved from peer table.
152 */
153 if (tcptw->tw_ts_recent_stamp &&
154 (!twp || (reuse && time_after32(ktime_get_seconds(),
155 tcptw->tw_ts_recent_stamp)))) {
156 /* In case of repair and re-using TIME-WAIT sockets we still
157 * want to be sure that it is safe as above but honor the
158 * sequence numbers and time stamps set as part of the repair
159 * process.
160 *
161 * Without this check re-using a TIME-WAIT socket with TCP
162 * repair would accumulate a -1 on the repair assigned
163 * sequence number. The first time it is reused the sequence
164 * is -1, the second time -2, etc. This fixes that issue
165 * without appearing to create any others.
166 */
167 if (likely(!tp->repair)) {
168 u32 seq = tcptw->tw_snd_nxt + 65535 + 2;
169
170 if (!seq)
171 seq = 1;
172 WRITE_ONCE(tp->write_seq, seq);
173 tp->rx_opt.ts_recent = tcptw->tw_ts_recent;
174 tp->rx_opt.ts_recent_stamp = tcptw->tw_ts_recent_stamp;
175 }
176 sock_hold(sktw);
177 return 1;
178 }
179
180 return 0;
181}
182EXPORT_SYMBOL_GPL(tcp_twsk_unique);
183
184static int tcp_v4_pre_connect(struct sock *sk, struct sockaddr *uaddr,
185 int addr_len)
186{
187 /* This check is replicated from tcp_v4_connect() and intended to
188 * prevent BPF program called below from accessing bytes that are out
189 * of the bound specified by user in addr_len.
190 */
191 if (addr_len < sizeof(struct sockaddr_in))
192 return -EINVAL;
193
194 sock_owned_by_me(sk);
195
196 return BPF_CGROUP_RUN_PROG_INET4_CONNECT(sk, uaddr);
197}
198
199/* This will initiate an outgoing connection. */
200int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
201{
202 struct sockaddr_in *usin = (struct sockaddr_in *)uaddr;
203 struct inet_timewait_death_row *tcp_death_row;
204 struct inet_sock *inet = inet_sk(sk);
205 struct tcp_sock *tp = tcp_sk(sk);
206 struct ip_options_rcu *inet_opt;
207 struct net *net = sock_net(sk);
208 __be16 orig_sport, orig_dport;
209 __be32 daddr, nexthop;
210 struct flowi4 *fl4;
211 struct rtable *rt;
212 int err;
213
214 if (addr_len < sizeof(struct sockaddr_in))
215 return -EINVAL;
216
217 if (usin->sin_family != AF_INET)
218 return -EAFNOSUPPORT;
219
220 nexthop = daddr = usin->sin_addr.s_addr;
221 inet_opt = rcu_dereference_protected(inet->inet_opt,
222 lockdep_sock_is_held(sk));
223 if (inet_opt && inet_opt->opt.srr) {
224 if (!daddr)
225 return -EINVAL;
226 nexthop = inet_opt->opt.faddr;
227 }
228
229 orig_sport = inet->inet_sport;
230 orig_dport = usin->sin_port;
231 fl4 = &inet->cork.fl.u.ip4;
232 rt = ip_route_connect(fl4, nexthop, inet->inet_saddr,
233 sk->sk_bound_dev_if, IPPROTO_TCP, orig_sport,
234 orig_dport, sk);
235 if (IS_ERR(rt)) {
236 err = PTR_ERR(rt);
237 if (err == -ENETUNREACH)
238 IP_INC_STATS(net, IPSTATS_MIB_OUTNOROUTES);
239 return err;
240 }
241
242 if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) {
243 ip_rt_put(rt);
244 return -ENETUNREACH;
245 }
246
247 if (!inet_opt || !inet_opt->opt.srr)
248 daddr = fl4->daddr;
249
250 tcp_death_row = &sock_net(sk)->ipv4.tcp_death_row;
251
252 if (!inet->inet_saddr) {
253 err = inet_bhash2_update_saddr(sk, &fl4->saddr, AF_INET);
254 if (err) {
255 ip_rt_put(rt);
256 return err;
257 }
258 } else {
259 sk_rcv_saddr_set(sk, inet->inet_saddr);
260 }
261
262 if (tp->rx_opt.ts_recent_stamp && inet->inet_daddr != daddr) {
263 /* Reset inherited state */
264 tp->rx_opt.ts_recent = 0;
265 tp->rx_opt.ts_recent_stamp = 0;
266 if (likely(!tp->repair))
267 WRITE_ONCE(tp->write_seq, 0);
268 }
269
270 inet->inet_dport = usin->sin_port;
271 sk_daddr_set(sk, daddr);
272
273 inet_csk(sk)->icsk_ext_hdr_len = 0;
274 if (inet_opt)
275 inet_csk(sk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
276
277 tp->rx_opt.mss_clamp = TCP_MSS_DEFAULT;
278
279 /* Socket identity is still unknown (sport may be zero).
280 * However we set state to SYN-SENT and not releasing socket
281 * lock select source port, enter ourselves into the hash tables and
282 * complete initialization after this.
283 */
284 tcp_set_state(sk, TCP_SYN_SENT);
285 err = inet_hash_connect(tcp_death_row, sk);
286 if (err)
287 goto failure;
288
289 sk_set_txhash(sk);
290
291 rt = ip_route_newports(fl4, rt, orig_sport, orig_dport,
292 inet->inet_sport, inet->inet_dport, sk);
293 if (IS_ERR(rt)) {
294 err = PTR_ERR(rt);
295 rt = NULL;
296 goto failure;
297 }
298 /* OK, now commit destination to socket. */
299 sk->sk_gso_type = SKB_GSO_TCPV4;
300 sk_setup_caps(sk, &rt->dst);
301 rt = NULL;
302
303 if (likely(!tp->repair)) {
304 if (!tp->write_seq)
305 WRITE_ONCE(tp->write_seq,
306 secure_tcp_seq(inet->inet_saddr,
307 inet->inet_daddr,
308 inet->inet_sport,
309 usin->sin_port));
310 tp->tsoffset = secure_tcp_ts_off(net, inet->inet_saddr,
311 inet->inet_daddr);
312 }
313
314 inet->inet_id = get_random_u16();
315
316 if (tcp_fastopen_defer_connect(sk, &err))
317 return err;
318 if (err)
319 goto failure;
320
321 err = tcp_connect(sk);
322
323 if (err)
324 goto failure;
325
326 return 0;
327
328failure:
329 /*
330 * This unhashes the socket and releases the local port,
331 * if necessary.
332 */
333 tcp_set_state(sk, TCP_CLOSE);
334 inet_bhash2_reset_saddr(sk);
335 ip_rt_put(rt);
336 sk->sk_route_caps = 0;
337 inet->inet_dport = 0;
338 return err;
339}
340EXPORT_SYMBOL(tcp_v4_connect);
341
342/*
343 * This routine reacts to ICMP_FRAG_NEEDED mtu indications as defined in RFC1191.
344 * It can be called through tcp_release_cb() if socket was owned by user
345 * at the time tcp_v4_err() was called to handle ICMP message.
346 */
347void tcp_v4_mtu_reduced(struct sock *sk)
348{
349 struct inet_sock *inet = inet_sk(sk);
350 struct dst_entry *dst;
351 u32 mtu;
352
353 if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE))
354 return;
355 mtu = READ_ONCE(tcp_sk(sk)->mtu_info);
356 dst = inet_csk_update_pmtu(sk, mtu);
357 if (!dst)
358 return;
359
360 /* Something is about to be wrong... Remember soft error
361 * for the case, if this connection will not able to recover.
362 */
363 if (mtu < dst_mtu(dst) && ip_dont_fragment(sk, dst))
364 sk->sk_err_soft = EMSGSIZE;
365
366 mtu = dst_mtu(dst);
367
368 if (inet->pmtudisc != IP_PMTUDISC_DONT &&
369 ip_sk_accept_pmtu(sk) &&
370 inet_csk(sk)->icsk_pmtu_cookie > mtu) {
371 tcp_sync_mss(sk, mtu);
372
373 /* Resend the TCP packet because it's
374 * clear that the old packet has been
375 * dropped. This is the new "fast" path mtu
376 * discovery.
377 */
378 tcp_simple_retransmit(sk);
379 } /* else let the usual retransmit timer handle it */
380}
381EXPORT_SYMBOL(tcp_v4_mtu_reduced);
382
383static void do_redirect(struct sk_buff *skb, struct sock *sk)
384{
385 struct dst_entry *dst = __sk_dst_check(sk, 0);
386
387 if (dst)
388 dst->ops->redirect(dst, sk, skb);
389}
390
391
392/* handle ICMP messages on TCP_NEW_SYN_RECV request sockets */
393void tcp_req_err(struct sock *sk, u32 seq, bool abort)
394{
395 struct request_sock *req = inet_reqsk(sk);
396 struct net *net = sock_net(sk);
397
398 /* ICMPs are not backlogged, hence we cannot get
399 * an established socket here.
400 */
401 if (seq != tcp_rsk(req)->snt_isn) {
402 __NET_INC_STATS(net, LINUX_MIB_OUTOFWINDOWICMPS);
403 } else if (abort) {
404 /*
405 * Still in SYN_RECV, just remove it silently.
406 * There is no good way to pass the error to the newly
407 * created socket, and POSIX does not want network
408 * errors returned from accept().
409 */
410 inet_csk_reqsk_queue_drop(req->rsk_listener, req);
411 tcp_listendrop(req->rsk_listener);
412 }
413 reqsk_put(req);
414}
415EXPORT_SYMBOL(tcp_req_err);
416
417/* TCP-LD (RFC 6069) logic */
418void tcp_ld_RTO_revert(struct sock *sk, u32 seq)
419{
420 struct inet_connection_sock *icsk = inet_csk(sk);
421 struct tcp_sock *tp = tcp_sk(sk);
422 struct sk_buff *skb;
423 s32 remaining;
424 u32 delta_us;
425
426 if (sock_owned_by_user(sk))
427 return;
428
429 if (seq != tp->snd_una || !icsk->icsk_retransmits ||
430 !icsk->icsk_backoff)
431 return;
432
433 skb = tcp_rtx_queue_head(sk);
434 if (WARN_ON_ONCE(!skb))
435 return;
436
437 icsk->icsk_backoff--;
438 icsk->icsk_rto = tp->srtt_us ? __tcp_set_rto(tp) : TCP_TIMEOUT_INIT;
439 icsk->icsk_rto = inet_csk_rto_backoff(icsk, TCP_RTO_MAX);
440
441 tcp_mstamp_refresh(tp);
442 delta_us = (u32)(tp->tcp_mstamp - tcp_skb_timestamp_us(skb));
443 remaining = icsk->icsk_rto - usecs_to_jiffies(delta_us);
444
445 if (remaining > 0) {
446 inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
447 remaining, TCP_RTO_MAX);
448 } else {
449 /* RTO revert clocked out retransmission.
450 * Will retransmit now.
451 */
452 tcp_retransmit_timer(sk);
453 }
454}
455EXPORT_SYMBOL(tcp_ld_RTO_revert);
456
457/*
458 * This routine is called by the ICMP module when it gets some
459 * sort of error condition. If err < 0 then the socket should
460 * be closed and the error returned to the user. If err > 0
461 * it's just the icmp type << 8 | icmp code. After adjustment
462 * header points to the first 8 bytes of the tcp header. We need
463 * to find the appropriate port.
464 *
465 * The locking strategy used here is very "optimistic". When
466 * someone else accesses the socket the ICMP is just dropped
467 * and for some paths there is no check at all.
468 * A more general error queue to queue errors for later handling
469 * is probably better.
470 *
471 */
472
473int tcp_v4_err(struct sk_buff *skb, u32 info)
474{
475 const struct iphdr *iph = (const struct iphdr *)skb->data;
476 struct tcphdr *th = (struct tcphdr *)(skb->data + (iph->ihl << 2));
477 struct tcp_sock *tp;
478 struct inet_sock *inet;
479 const int type = icmp_hdr(skb)->type;
480 const int code = icmp_hdr(skb)->code;
481 struct sock *sk;
482 struct request_sock *fastopen;
483 u32 seq, snd_una;
484 int err;
485 struct net *net = dev_net(skb->dev);
486
487 sk = __inet_lookup_established(net, net->ipv4.tcp_death_row.hashinfo,
488 iph->daddr, th->dest, iph->saddr,
489 ntohs(th->source), inet_iif(skb), 0);
490 if (!sk) {
491 __ICMP_INC_STATS(net, ICMP_MIB_INERRORS);
492 return -ENOENT;
493 }
494 if (sk->sk_state == TCP_TIME_WAIT) {
495 inet_twsk_put(inet_twsk(sk));
496 return 0;
497 }
498 seq = ntohl(th->seq);
499 if (sk->sk_state == TCP_NEW_SYN_RECV) {
500 tcp_req_err(sk, seq, type == ICMP_PARAMETERPROB ||
501 type == ICMP_TIME_EXCEEDED ||
502 (type == ICMP_DEST_UNREACH &&
503 (code == ICMP_NET_UNREACH ||
504 code == ICMP_HOST_UNREACH)));
505 return 0;
506 }
507
508 bh_lock_sock(sk);
509 /* If too many ICMPs get dropped on busy
510 * servers this needs to be solved differently.
511 * We do take care of PMTU discovery (RFC1191) special case :
512 * we can receive locally generated ICMP messages while socket is held.
513 */
514 if (sock_owned_by_user(sk)) {
515 if (!(type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED))
516 __NET_INC_STATS(net, LINUX_MIB_LOCKDROPPEDICMPS);
517 }
518 if (sk->sk_state == TCP_CLOSE)
519 goto out;
520
521 if (static_branch_unlikely(&ip4_min_ttl)) {
522 /* min_ttl can be changed concurrently from do_ip_setsockopt() */
523 if (unlikely(iph->ttl < READ_ONCE(inet_sk(sk)->min_ttl))) {
524 __NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP);
525 goto out;
526 }
527 }
528
529 tp = tcp_sk(sk);
530 /* XXX (TFO) - tp->snd_una should be ISN (tcp_create_openreq_child() */
531 fastopen = rcu_dereference(tp->fastopen_rsk);
532 snd_una = fastopen ? tcp_rsk(fastopen)->snt_isn : tp->snd_una;
533 if (sk->sk_state != TCP_LISTEN &&
534 !between(seq, snd_una, tp->snd_nxt)) {
535 __NET_INC_STATS(net, LINUX_MIB_OUTOFWINDOWICMPS);
536 goto out;
537 }
538
539 switch (type) {
540 case ICMP_REDIRECT:
541 if (!sock_owned_by_user(sk))
542 do_redirect(skb, sk);
543 goto out;
544 case ICMP_SOURCE_QUENCH:
545 /* Just silently ignore these. */
546 goto out;
547 case ICMP_PARAMETERPROB:
548 err = EPROTO;
549 break;
550 case ICMP_DEST_UNREACH:
551 if (code > NR_ICMP_UNREACH)
552 goto out;
553
554 if (code == ICMP_FRAG_NEEDED) { /* PMTU discovery (RFC1191) */
555 /* We are not interested in TCP_LISTEN and open_requests
556 * (SYN-ACKs send out by Linux are always <576bytes so
557 * they should go through unfragmented).
558 */
559 if (sk->sk_state == TCP_LISTEN)
560 goto out;
561
562 WRITE_ONCE(tp->mtu_info, info);
563 if (!sock_owned_by_user(sk)) {
564 tcp_v4_mtu_reduced(sk);
565 } else {
566 if (!test_and_set_bit(TCP_MTU_REDUCED_DEFERRED, &sk->sk_tsq_flags))
567 sock_hold(sk);
568 }
569 goto out;
570 }
571
572 err = icmp_err_convert[code].errno;
573 /* check if this ICMP message allows revert of backoff.
574 * (see RFC 6069)
575 */
576 if (!fastopen &&
577 (code == ICMP_NET_UNREACH || code == ICMP_HOST_UNREACH))
578 tcp_ld_RTO_revert(sk, seq);
579 break;
580 case ICMP_TIME_EXCEEDED:
581 err = EHOSTUNREACH;
582 break;
583 default:
584 goto out;
585 }
586
587 switch (sk->sk_state) {
588 case TCP_SYN_SENT:
589 case TCP_SYN_RECV:
590 /* Only in fast or simultaneous open. If a fast open socket is
591 * already accepted it is treated as a connected one below.
592 */
593 if (fastopen && !fastopen->sk)
594 break;
595
596 ip_icmp_error(sk, skb, err, th->dest, info, (u8 *)th);
597
598 if (!sock_owned_by_user(sk)) {
599 sk->sk_err = err;
600
601 sk_error_report(sk);
602
603 tcp_done(sk);
604 } else {
605 sk->sk_err_soft = err;
606 }
607 goto out;
608 }
609
610 /* If we've already connected we will keep trying
611 * until we time out, or the user gives up.
612 *
613 * rfc1122 4.2.3.9 allows to consider as hard errors
614 * only PROTO_UNREACH and PORT_UNREACH (well, FRAG_FAILED too,
615 * but it is obsoleted by pmtu discovery).
616 *
617 * Note, that in modern internet, where routing is unreliable
618 * and in each dark corner broken firewalls sit, sending random
619 * errors ordered by their masters even this two messages finally lose
620 * their original sense (even Linux sends invalid PORT_UNREACHs)
621 *
622 * Now we are in compliance with RFCs.
623 * --ANK (980905)
624 */
625
626 inet = inet_sk(sk);
627 if (!sock_owned_by_user(sk) && inet->recverr) {
628 sk->sk_err = err;
629 sk_error_report(sk);
630 } else { /* Only an error on timeout */
631 sk->sk_err_soft = err;
632 }
633
634out:
635 bh_unlock_sock(sk);
636 sock_put(sk);
637 return 0;
638}
639
640void __tcp_v4_send_check(struct sk_buff *skb, __be32 saddr, __be32 daddr)
641{
642 struct tcphdr *th = tcp_hdr(skb);
643
644 th->check = ~tcp_v4_check(skb->len, saddr, daddr, 0);
645 skb->csum_start = skb_transport_header(skb) - skb->head;
646 skb->csum_offset = offsetof(struct tcphdr, check);
647}
648
649/* This routine computes an IPv4 TCP checksum. */
650void tcp_v4_send_check(struct sock *sk, struct sk_buff *skb)
651{
652 const struct inet_sock *inet = inet_sk(sk);
653
654 __tcp_v4_send_check(skb, inet->inet_saddr, inet->inet_daddr);
655}
656EXPORT_SYMBOL(tcp_v4_send_check);
657
658/*
659 * This routine will send an RST to the other tcp.
660 *
661 * Someone asks: why I NEVER use socket parameters (TOS, TTL etc.)
662 * for reset.
663 * Answer: if a packet caused RST, it is not for a socket
664 * existing in our system, if it is matched to a socket,
665 * it is just duplicate segment or bug in other side's TCP.
666 * So that we build reply only basing on parameters
667 * arrived with segment.
668 * Exception: precedence violation. We do not implement it in any case.
669 */
670
671#ifdef CONFIG_TCP_MD5SIG
672#define OPTION_BYTES TCPOLEN_MD5SIG_ALIGNED
673#else
674#define OPTION_BYTES sizeof(__be32)
675#endif
676
677static void tcp_v4_send_reset(const struct sock *sk, struct sk_buff *skb)
678{
679 const struct tcphdr *th = tcp_hdr(skb);
680 struct {
681 struct tcphdr th;
682 __be32 opt[OPTION_BYTES / sizeof(__be32)];
683 } rep;
684 struct ip_reply_arg arg;
685#ifdef CONFIG_TCP_MD5SIG
686 struct tcp_md5sig_key *key = NULL;
687 const __u8 *hash_location = NULL;
688 unsigned char newhash[16];
689 int genhash;
690 struct sock *sk1 = NULL;
691#endif
692 u64 transmit_time = 0;
693 struct sock *ctl_sk;
694 struct net *net;
695
696 /* Never send a reset in response to a reset. */
697 if (th->rst)
698 return;
699
700 /* If sk not NULL, it means we did a successful lookup and incoming
701 * route had to be correct. prequeue might have dropped our dst.
702 */
703 if (!sk && skb_rtable(skb)->rt_type != RTN_LOCAL)
704 return;
705
706 /* Swap the send and the receive. */
707 memset(&rep, 0, sizeof(rep));
708 rep.th.dest = th->source;
709 rep.th.source = th->dest;
710 rep.th.doff = sizeof(struct tcphdr) / 4;
711 rep.th.rst = 1;
712
713 if (th->ack) {
714 rep.th.seq = th->ack_seq;
715 } else {
716 rep.th.ack = 1;
717 rep.th.ack_seq = htonl(ntohl(th->seq) + th->syn + th->fin +
718 skb->len - (th->doff << 2));
719 }
720
721 memset(&arg, 0, sizeof(arg));
722 arg.iov[0].iov_base = (unsigned char *)&rep;
723 arg.iov[0].iov_len = sizeof(rep.th);
724
725 net = sk ? sock_net(sk) : dev_net(skb_dst(skb)->dev);
726#ifdef CONFIG_TCP_MD5SIG
727 rcu_read_lock();
728 hash_location = tcp_parse_md5sig_option(th);
729 if (sk && sk_fullsock(sk)) {
730 const union tcp_md5_addr *addr;
731 int l3index;
732
733 /* sdif set, means packet ingressed via a device
734 * in an L3 domain and inet_iif is set to it.
735 */
736 l3index = tcp_v4_sdif(skb) ? inet_iif(skb) : 0;
737 addr = (union tcp_md5_addr *)&ip_hdr(skb)->saddr;
738 key = tcp_md5_do_lookup(sk, l3index, addr, AF_INET);
739 } else if (hash_location) {
740 const union tcp_md5_addr *addr;
741 int sdif = tcp_v4_sdif(skb);
742 int dif = inet_iif(skb);
743 int l3index;
744
745 /*
746 * active side is lost. Try to find listening socket through
747 * source port, and then find md5 key through listening socket.
748 * we are not loose security here:
749 * Incoming packet is checked with md5 hash with finding key,
750 * no RST generated if md5 hash doesn't match.
751 */
752 sk1 = __inet_lookup_listener(net, net->ipv4.tcp_death_row.hashinfo,
753 NULL, 0, ip_hdr(skb)->saddr,
754 th->source, ip_hdr(skb)->daddr,
755 ntohs(th->source), dif, sdif);
756 /* don't send rst if it can't find key */
757 if (!sk1)
758 goto out;
759
760 /* sdif set, means packet ingressed via a device
761 * in an L3 domain and dif is set to it.
762 */
763 l3index = sdif ? dif : 0;
764 addr = (union tcp_md5_addr *)&ip_hdr(skb)->saddr;
765 key = tcp_md5_do_lookup(sk1, l3index, addr, AF_INET);
766 if (!key)
767 goto out;
768
769
770 genhash = tcp_v4_md5_hash_skb(newhash, key, NULL, skb);
771 if (genhash || memcmp(hash_location, newhash, 16) != 0)
772 goto out;
773
774 }
775
776 if (key) {
777 rep.opt[0] = htonl((TCPOPT_NOP << 24) |
778 (TCPOPT_NOP << 16) |
779 (TCPOPT_MD5SIG << 8) |
780 TCPOLEN_MD5SIG);
781 /* Update length and the length the header thinks exists */
782 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED;
783 rep.th.doff = arg.iov[0].iov_len / 4;
784
785 tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[1],
786 key, ip_hdr(skb)->saddr,
787 ip_hdr(skb)->daddr, &rep.th);
788 }
789#endif
790 /* Can't co-exist with TCPMD5, hence check rep.opt[0] */
791 if (rep.opt[0] == 0) {
792 __be32 mrst = mptcp_reset_option(skb);
793
794 if (mrst) {
795 rep.opt[0] = mrst;
796 arg.iov[0].iov_len += sizeof(mrst);
797 rep.th.doff = arg.iov[0].iov_len / 4;
798 }
799 }
800
801 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
802 ip_hdr(skb)->saddr, /* XXX */
803 arg.iov[0].iov_len, IPPROTO_TCP, 0);
804 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
805 arg.flags = (sk && inet_sk_transparent(sk)) ? IP_REPLY_ARG_NOSRCCHECK : 0;
806
807 /* When socket is gone, all binding information is lost.
808 * routing might fail in this case. No choice here, if we choose to force
809 * input interface, we will misroute in case of asymmetric route.
810 */
811 if (sk) {
812 arg.bound_dev_if = sk->sk_bound_dev_if;
813 if (sk_fullsock(sk))
814 trace_tcp_send_reset(sk, skb);
815 }
816
817 BUILD_BUG_ON(offsetof(struct sock, sk_bound_dev_if) !=
818 offsetof(struct inet_timewait_sock, tw_bound_dev_if));
819
820 arg.tos = ip_hdr(skb)->tos;
821 arg.uid = sock_net_uid(net, sk && sk_fullsock(sk) ? sk : NULL);
822 local_bh_disable();
823 ctl_sk = this_cpu_read(ipv4_tcp_sk);
824 sock_net_set(ctl_sk, net);
825 if (sk) {
826 ctl_sk->sk_mark = (sk->sk_state == TCP_TIME_WAIT) ?
827 inet_twsk(sk)->tw_mark : sk->sk_mark;
828 ctl_sk->sk_priority = (sk->sk_state == TCP_TIME_WAIT) ?
829 inet_twsk(sk)->tw_priority : sk->sk_priority;
830 transmit_time = tcp_transmit_time(sk);
831 xfrm_sk_clone_policy(ctl_sk, sk);
832 }
833 ip_send_unicast_reply(ctl_sk,
834 skb, &TCP_SKB_CB(skb)->header.h4.opt,
835 ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
836 &arg, arg.iov[0].iov_len,
837 transmit_time);
838
839 ctl_sk->sk_mark = 0;
840 xfrm_sk_free_policy(ctl_sk);
841 sock_net_set(ctl_sk, &init_net);
842 __TCP_INC_STATS(net, TCP_MIB_OUTSEGS);
843 __TCP_INC_STATS(net, TCP_MIB_OUTRSTS);
844 local_bh_enable();
845
846#ifdef CONFIG_TCP_MD5SIG
847out:
848 rcu_read_unlock();
849#endif
850}
851
852/* The code following below sending ACKs in SYN-RECV and TIME-WAIT states
853 outside socket context is ugly, certainly. What can I do?
854 */
855
856static void tcp_v4_send_ack(const struct sock *sk,
857 struct sk_buff *skb, u32 seq, u32 ack,
858 u32 win, u32 tsval, u32 tsecr, int oif,
859 struct tcp_md5sig_key *key,
860 int reply_flags, u8 tos)
861{
862 const struct tcphdr *th = tcp_hdr(skb);
863 struct {
864 struct tcphdr th;
865 __be32 opt[(TCPOLEN_TSTAMP_ALIGNED >> 2)
866#ifdef CONFIG_TCP_MD5SIG
867 + (TCPOLEN_MD5SIG_ALIGNED >> 2)
868#endif
869 ];
870 } rep;
871 struct net *net = sock_net(sk);
872 struct ip_reply_arg arg;
873 struct sock *ctl_sk;
874 u64 transmit_time;
875
876 memset(&rep.th, 0, sizeof(struct tcphdr));
877 memset(&arg, 0, sizeof(arg));
878
879 arg.iov[0].iov_base = (unsigned char *)&rep;
880 arg.iov[0].iov_len = sizeof(rep.th);
881 if (tsecr) {
882 rep.opt[0] = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
883 (TCPOPT_TIMESTAMP << 8) |
884 TCPOLEN_TIMESTAMP);
885 rep.opt[1] = htonl(tsval);
886 rep.opt[2] = htonl(tsecr);
887 arg.iov[0].iov_len += TCPOLEN_TSTAMP_ALIGNED;
888 }
889
890 /* Swap the send and the receive. */
891 rep.th.dest = th->source;
892 rep.th.source = th->dest;
893 rep.th.doff = arg.iov[0].iov_len / 4;
894 rep.th.seq = htonl(seq);
895 rep.th.ack_seq = htonl(ack);
896 rep.th.ack = 1;
897 rep.th.window = htons(win);
898
899#ifdef CONFIG_TCP_MD5SIG
900 if (key) {
901 int offset = (tsecr) ? 3 : 0;
902
903 rep.opt[offset++] = htonl((TCPOPT_NOP << 24) |
904 (TCPOPT_NOP << 16) |
905 (TCPOPT_MD5SIG << 8) |
906 TCPOLEN_MD5SIG);
907 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED;
908 rep.th.doff = arg.iov[0].iov_len/4;
909
910 tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[offset],
911 key, ip_hdr(skb)->saddr,
912 ip_hdr(skb)->daddr, &rep.th);
913 }
914#endif
915 arg.flags = reply_flags;
916 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
917 ip_hdr(skb)->saddr, /* XXX */
918 arg.iov[0].iov_len, IPPROTO_TCP, 0);
919 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
920 if (oif)
921 arg.bound_dev_if = oif;
922 arg.tos = tos;
923 arg.uid = sock_net_uid(net, sk_fullsock(sk) ? sk : NULL);
924 local_bh_disable();
925 ctl_sk = this_cpu_read(ipv4_tcp_sk);
926 sock_net_set(ctl_sk, net);
927 ctl_sk->sk_mark = (sk->sk_state == TCP_TIME_WAIT) ?
928 inet_twsk(sk)->tw_mark : sk->sk_mark;
929 ctl_sk->sk_priority = (sk->sk_state == TCP_TIME_WAIT) ?
930 inet_twsk(sk)->tw_priority : sk->sk_priority;
931 transmit_time = tcp_transmit_time(sk);
932 ip_send_unicast_reply(ctl_sk,
933 skb, &TCP_SKB_CB(skb)->header.h4.opt,
934 ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
935 &arg, arg.iov[0].iov_len,
936 transmit_time);
937
938 ctl_sk->sk_mark = 0;
939 sock_net_set(ctl_sk, &init_net);
940 __TCP_INC_STATS(net, TCP_MIB_OUTSEGS);
941 local_bh_enable();
942}
943
944static void tcp_v4_timewait_ack(struct sock *sk, struct sk_buff *skb)
945{
946 struct inet_timewait_sock *tw = inet_twsk(sk);
947 struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
948
949 tcp_v4_send_ack(sk, skb,
950 tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
951 tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
952 tcp_time_stamp_raw() + tcptw->tw_ts_offset,
953 tcptw->tw_ts_recent,
954 tw->tw_bound_dev_if,
955 tcp_twsk_md5_key(tcptw),
956 tw->tw_transparent ? IP_REPLY_ARG_NOSRCCHECK : 0,
957 tw->tw_tos
958 );
959
960 inet_twsk_put(tw);
961}
962
963static void tcp_v4_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb,
964 struct request_sock *req)
965{
966 const union tcp_md5_addr *addr;
967 int l3index;
968
969 /* sk->sk_state == TCP_LISTEN -> for regular TCP_SYN_RECV
970 * sk->sk_state == TCP_SYN_RECV -> for Fast Open.
971 */
972 u32 seq = (sk->sk_state == TCP_LISTEN) ? tcp_rsk(req)->snt_isn + 1 :
973 tcp_sk(sk)->snd_nxt;
974
975 /* RFC 7323 2.3
976 * The window field (SEG.WND) of every outgoing segment, with the
977 * exception of <SYN> segments, MUST be right-shifted by
978 * Rcv.Wind.Shift bits:
979 */
980 addr = (union tcp_md5_addr *)&ip_hdr(skb)->saddr;
981 l3index = tcp_v4_sdif(skb) ? inet_iif(skb) : 0;
982 tcp_v4_send_ack(sk, skb, seq,
983 tcp_rsk(req)->rcv_nxt,
984 req->rsk_rcv_wnd >> inet_rsk(req)->rcv_wscale,
985 tcp_time_stamp_raw() + tcp_rsk(req)->ts_off,
986 req->ts_recent,
987 0,
988 tcp_md5_do_lookup(sk, l3index, addr, AF_INET),
989 inet_rsk(req)->no_srccheck ? IP_REPLY_ARG_NOSRCCHECK : 0,
990 ip_hdr(skb)->tos);
991}
992
993/*
994 * Send a SYN-ACK after having received a SYN.
995 * This still operates on a request_sock only, not on a big
996 * socket.
997 */
998static int tcp_v4_send_synack(const struct sock *sk, struct dst_entry *dst,
999 struct flowi *fl,
1000 struct request_sock *req,
1001 struct tcp_fastopen_cookie *foc,
1002 enum tcp_synack_type synack_type,
1003 struct sk_buff *syn_skb)
1004{
1005 const struct inet_request_sock *ireq = inet_rsk(req);
1006 struct flowi4 fl4;
1007 int err = -1;
1008 struct sk_buff *skb;
1009 u8 tos;
1010
1011 /* First, grab a route. */
1012 if (!dst && (dst = inet_csk_route_req(sk, &fl4, req)) == NULL)
1013 return -1;
1014
1015 skb = tcp_make_synack(sk, dst, req, foc, synack_type, syn_skb);
1016
1017 if (skb) {
1018 __tcp_v4_send_check(skb, ireq->ir_loc_addr, ireq->ir_rmt_addr);
1019
1020 tos = READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_reflect_tos) ?
1021 (tcp_rsk(req)->syn_tos & ~INET_ECN_MASK) |
1022 (inet_sk(sk)->tos & INET_ECN_MASK) :
1023 inet_sk(sk)->tos;
1024
1025 if (!INET_ECN_is_capable(tos) &&
1026 tcp_bpf_ca_needs_ecn((struct sock *)req))
1027 tos |= INET_ECN_ECT_0;
1028
1029 rcu_read_lock();
1030 err = ip_build_and_send_pkt(skb, sk, ireq->ir_loc_addr,
1031 ireq->ir_rmt_addr,
1032 rcu_dereference(ireq->ireq_opt),
1033 tos);
1034 rcu_read_unlock();
1035 err = net_xmit_eval(err);
1036 }
1037
1038 return err;
1039}
1040
1041/*
1042 * IPv4 request_sock destructor.
1043 */
1044static void tcp_v4_reqsk_destructor(struct request_sock *req)
1045{
1046 kfree(rcu_dereference_protected(inet_rsk(req)->ireq_opt, 1));
1047}
1048
1049#ifdef CONFIG_TCP_MD5SIG
1050/*
1051 * RFC2385 MD5 checksumming requires a mapping of
1052 * IP address->MD5 Key.
1053 * We need to maintain these in the sk structure.
1054 */
1055
1056DEFINE_STATIC_KEY_DEFERRED_FALSE(tcp_md5_needed, HZ);
1057EXPORT_SYMBOL(tcp_md5_needed);
1058
1059static bool better_md5_match(struct tcp_md5sig_key *old, struct tcp_md5sig_key *new)
1060{
1061 if (!old)
1062 return true;
1063
1064 /* l3index always overrides non-l3index */
1065 if (old->l3index && new->l3index == 0)
1066 return false;
1067 if (old->l3index == 0 && new->l3index)
1068 return true;
1069
1070 return old->prefixlen < new->prefixlen;
1071}
1072
1073/* Find the Key structure for an address. */
1074struct tcp_md5sig_key *__tcp_md5_do_lookup(const struct sock *sk, int l3index,
1075 const union tcp_md5_addr *addr,
1076 int family)
1077{
1078 const struct tcp_sock *tp = tcp_sk(sk);
1079 struct tcp_md5sig_key *key;
1080 const struct tcp_md5sig_info *md5sig;
1081 __be32 mask;
1082 struct tcp_md5sig_key *best_match = NULL;
1083 bool match;
1084
1085 /* caller either holds rcu_read_lock() or socket lock */
1086 md5sig = rcu_dereference_check(tp->md5sig_info,
1087 lockdep_sock_is_held(sk));
1088 if (!md5sig)
1089 return NULL;
1090
1091 hlist_for_each_entry_rcu(key, &md5sig->head, node,
1092 lockdep_sock_is_held(sk)) {
1093 if (key->family != family)
1094 continue;
1095 if (key->flags & TCP_MD5SIG_FLAG_IFINDEX && key->l3index != l3index)
1096 continue;
1097 if (family == AF_INET) {
1098 mask = inet_make_mask(key->prefixlen);
1099 match = (key->addr.a4.s_addr & mask) ==
1100 (addr->a4.s_addr & mask);
1101#if IS_ENABLED(CONFIG_IPV6)
1102 } else if (family == AF_INET6) {
1103 match = ipv6_prefix_equal(&key->addr.a6, &addr->a6,
1104 key->prefixlen);
1105#endif
1106 } else {
1107 match = false;
1108 }
1109
1110 if (match && better_md5_match(best_match, key))
1111 best_match = key;
1112 }
1113 return best_match;
1114}
1115EXPORT_SYMBOL(__tcp_md5_do_lookup);
1116
1117static struct tcp_md5sig_key *tcp_md5_do_lookup_exact(const struct sock *sk,
1118 const union tcp_md5_addr *addr,
1119 int family, u8 prefixlen,
1120 int l3index, u8 flags)
1121{
1122 const struct tcp_sock *tp = tcp_sk(sk);
1123 struct tcp_md5sig_key *key;
1124 unsigned int size = sizeof(struct in_addr);
1125 const struct tcp_md5sig_info *md5sig;
1126
1127 /* caller either holds rcu_read_lock() or socket lock */
1128 md5sig = rcu_dereference_check(tp->md5sig_info,
1129 lockdep_sock_is_held(sk));
1130 if (!md5sig)
1131 return NULL;
1132#if IS_ENABLED(CONFIG_IPV6)
1133 if (family == AF_INET6)
1134 size = sizeof(struct in6_addr);
1135#endif
1136 hlist_for_each_entry_rcu(key, &md5sig->head, node,
1137 lockdep_sock_is_held(sk)) {
1138 if (key->family != family)
1139 continue;
1140 if ((key->flags & TCP_MD5SIG_FLAG_IFINDEX) != (flags & TCP_MD5SIG_FLAG_IFINDEX))
1141 continue;
1142 if (key->l3index != l3index)
1143 continue;
1144 if (!memcmp(&key->addr, addr, size) &&
1145 key->prefixlen == prefixlen)
1146 return key;
1147 }
1148 return NULL;
1149}
1150
1151struct tcp_md5sig_key *tcp_v4_md5_lookup(const struct sock *sk,
1152 const struct sock *addr_sk)
1153{
1154 const union tcp_md5_addr *addr;
1155 int l3index;
1156
1157 l3index = l3mdev_master_ifindex_by_index(sock_net(sk),
1158 addr_sk->sk_bound_dev_if);
1159 addr = (const union tcp_md5_addr *)&addr_sk->sk_daddr;
1160 return tcp_md5_do_lookup(sk, l3index, addr, AF_INET);
1161}
1162EXPORT_SYMBOL(tcp_v4_md5_lookup);
1163
1164static int tcp_md5sig_info_add(struct sock *sk, gfp_t gfp)
1165{
1166 struct tcp_sock *tp = tcp_sk(sk);
1167 struct tcp_md5sig_info *md5sig;
1168
1169 md5sig = kmalloc(sizeof(*md5sig), gfp);
1170 if (!md5sig)
1171 return -ENOMEM;
1172
1173 sk_gso_disable(sk);
1174 INIT_HLIST_HEAD(&md5sig->head);
1175 rcu_assign_pointer(tp->md5sig_info, md5sig);
1176 return 0;
1177}
1178
1179/* This can be called on a newly created socket, from other files */
1180static int __tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr,
1181 int family, u8 prefixlen, int l3index, u8 flags,
1182 const u8 *newkey, u8 newkeylen, gfp_t gfp)
1183{
1184 /* Add Key to the list */
1185 struct tcp_md5sig_key *key;
1186 struct tcp_sock *tp = tcp_sk(sk);
1187 struct tcp_md5sig_info *md5sig;
1188
1189 key = tcp_md5_do_lookup_exact(sk, addr, family, prefixlen, l3index, flags);
1190 if (key) {
1191 /* Pre-existing entry - just update that one.
1192 * Note that the key might be used concurrently.
1193 * data_race() is telling kcsan that we do not care of
1194 * key mismatches, since changing MD5 key on live flows
1195 * can lead to packet drops.
1196 */
1197 data_race(memcpy(key->key, newkey, newkeylen));
1198
1199 /* Pairs with READ_ONCE() in tcp_md5_hash_key().
1200 * Also note that a reader could catch new key->keylen value
1201 * but old key->key[], this is the reason we use __GFP_ZERO
1202 * at sock_kmalloc() time below these lines.
1203 */
1204 WRITE_ONCE(key->keylen, newkeylen);
1205
1206 return 0;
1207 }
1208
1209 md5sig = rcu_dereference_protected(tp->md5sig_info,
1210 lockdep_sock_is_held(sk));
1211
1212 key = sock_kmalloc(sk, sizeof(*key), gfp | __GFP_ZERO);
1213 if (!key)
1214 return -ENOMEM;
1215 if (!tcp_alloc_md5sig_pool()) {
1216 sock_kfree_s(sk, key, sizeof(*key));
1217 return -ENOMEM;
1218 }
1219
1220 memcpy(key->key, newkey, newkeylen);
1221 key->keylen = newkeylen;
1222 key->family = family;
1223 key->prefixlen = prefixlen;
1224 key->l3index = l3index;
1225 key->flags = flags;
1226 memcpy(&key->addr, addr,
1227 (IS_ENABLED(CONFIG_IPV6) && family == AF_INET6) ? sizeof(struct in6_addr) :
1228 sizeof(struct in_addr));
1229 hlist_add_head_rcu(&key->node, &md5sig->head);
1230 return 0;
1231}
1232
1233int tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr,
1234 int family, u8 prefixlen, int l3index, u8 flags,
1235 const u8 *newkey, u8 newkeylen)
1236{
1237 struct tcp_sock *tp = tcp_sk(sk);
1238
1239 if (!rcu_dereference_protected(tp->md5sig_info, lockdep_sock_is_held(sk))) {
1240 if (tcp_md5sig_info_add(sk, GFP_KERNEL))
1241 return -ENOMEM;
1242
1243 if (!static_branch_inc(&tcp_md5_needed.key)) {
1244 struct tcp_md5sig_info *md5sig;
1245
1246 md5sig = rcu_dereference_protected(tp->md5sig_info, lockdep_sock_is_held(sk));
1247 rcu_assign_pointer(tp->md5sig_info, NULL);
1248 kfree_rcu(md5sig, rcu);
1249 return -EUSERS;
1250 }
1251 }
1252
1253 return __tcp_md5_do_add(sk, addr, family, prefixlen, l3index, flags,
1254 newkey, newkeylen, GFP_KERNEL);
1255}
1256EXPORT_SYMBOL(tcp_md5_do_add);
1257
1258int tcp_md5_key_copy(struct sock *sk, const union tcp_md5_addr *addr,
1259 int family, u8 prefixlen, int l3index,
1260 struct tcp_md5sig_key *key)
1261{
1262 struct tcp_sock *tp = tcp_sk(sk);
1263
1264 if (!rcu_dereference_protected(tp->md5sig_info, lockdep_sock_is_held(sk))) {
1265 if (tcp_md5sig_info_add(sk, sk_gfp_mask(sk, GFP_ATOMIC)))
1266 return -ENOMEM;
1267
1268 if (!static_key_fast_inc_not_disabled(&tcp_md5_needed.key.key)) {
1269 struct tcp_md5sig_info *md5sig;
1270
1271 md5sig = rcu_dereference_protected(tp->md5sig_info, lockdep_sock_is_held(sk));
1272 net_warn_ratelimited("Too many TCP-MD5 keys in the system\n");
1273 rcu_assign_pointer(tp->md5sig_info, NULL);
1274 kfree_rcu(md5sig, rcu);
1275 return -EUSERS;
1276 }
1277 }
1278
1279 return __tcp_md5_do_add(sk, addr, family, prefixlen, l3index,
1280 key->flags, key->key, key->keylen,
1281 sk_gfp_mask(sk, GFP_ATOMIC));
1282}
1283EXPORT_SYMBOL(tcp_md5_key_copy);
1284
1285int tcp_md5_do_del(struct sock *sk, const union tcp_md5_addr *addr, int family,
1286 u8 prefixlen, int l3index, u8 flags)
1287{
1288 struct tcp_md5sig_key *key;
1289
1290 key = tcp_md5_do_lookup_exact(sk, addr, family, prefixlen, l3index, flags);
1291 if (!key)
1292 return -ENOENT;
1293 hlist_del_rcu(&key->node);
1294 atomic_sub(sizeof(*key), &sk->sk_omem_alloc);
1295 kfree_rcu(key, rcu);
1296 return 0;
1297}
1298EXPORT_SYMBOL(tcp_md5_do_del);
1299
1300static void tcp_clear_md5_list(struct sock *sk)
1301{
1302 struct tcp_sock *tp = tcp_sk(sk);
1303 struct tcp_md5sig_key *key;
1304 struct hlist_node *n;
1305 struct tcp_md5sig_info *md5sig;
1306
1307 md5sig = rcu_dereference_protected(tp->md5sig_info, 1);
1308
1309 hlist_for_each_entry_safe(key, n, &md5sig->head, node) {
1310 hlist_del_rcu(&key->node);
1311 atomic_sub(sizeof(*key), &sk->sk_omem_alloc);
1312 kfree_rcu(key, rcu);
1313 }
1314}
1315
1316static int tcp_v4_parse_md5_keys(struct sock *sk, int optname,
1317 sockptr_t optval, int optlen)
1318{
1319 struct tcp_md5sig cmd;
1320 struct sockaddr_in *sin = (struct sockaddr_in *)&cmd.tcpm_addr;
1321 const union tcp_md5_addr *addr;
1322 u8 prefixlen = 32;
1323 int l3index = 0;
1324 u8 flags;
1325
1326 if (optlen < sizeof(cmd))
1327 return -EINVAL;
1328
1329 if (copy_from_sockptr(&cmd, optval, sizeof(cmd)))
1330 return -EFAULT;
1331
1332 if (sin->sin_family != AF_INET)
1333 return -EINVAL;
1334
1335 flags = cmd.tcpm_flags & TCP_MD5SIG_FLAG_IFINDEX;
1336
1337 if (optname == TCP_MD5SIG_EXT &&
1338 cmd.tcpm_flags & TCP_MD5SIG_FLAG_PREFIX) {
1339 prefixlen = cmd.tcpm_prefixlen;
1340 if (prefixlen > 32)
1341 return -EINVAL;
1342 }
1343
1344 if (optname == TCP_MD5SIG_EXT && cmd.tcpm_ifindex &&
1345 cmd.tcpm_flags & TCP_MD5SIG_FLAG_IFINDEX) {
1346 struct net_device *dev;
1347
1348 rcu_read_lock();
1349 dev = dev_get_by_index_rcu(sock_net(sk), cmd.tcpm_ifindex);
1350 if (dev && netif_is_l3_master(dev))
1351 l3index = dev->ifindex;
1352
1353 rcu_read_unlock();
1354
1355 /* ok to reference set/not set outside of rcu;
1356 * right now device MUST be an L3 master
1357 */
1358 if (!dev || !l3index)
1359 return -EINVAL;
1360 }
1361
1362 addr = (union tcp_md5_addr *)&sin->sin_addr.s_addr;
1363
1364 if (!cmd.tcpm_keylen)
1365 return tcp_md5_do_del(sk, addr, AF_INET, prefixlen, l3index, flags);
1366
1367 if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN)
1368 return -EINVAL;
1369
1370 return tcp_md5_do_add(sk, addr, AF_INET, prefixlen, l3index, flags,
1371 cmd.tcpm_key, cmd.tcpm_keylen);
1372}
1373
1374static int tcp_v4_md5_hash_headers(struct tcp_md5sig_pool *hp,
1375 __be32 daddr, __be32 saddr,
1376 const struct tcphdr *th, int nbytes)
1377{
1378 struct tcp4_pseudohdr *bp;
1379 struct scatterlist sg;
1380 struct tcphdr *_th;
1381
1382 bp = hp->scratch;
1383 bp->saddr = saddr;
1384 bp->daddr = daddr;
1385 bp->pad = 0;
1386 bp->protocol = IPPROTO_TCP;
1387 bp->len = cpu_to_be16(nbytes);
1388
1389 _th = (struct tcphdr *)(bp + 1);
1390 memcpy(_th, th, sizeof(*th));
1391 _th->check = 0;
1392
1393 sg_init_one(&sg, bp, sizeof(*bp) + sizeof(*th));
1394 ahash_request_set_crypt(hp->md5_req, &sg, NULL,
1395 sizeof(*bp) + sizeof(*th));
1396 return crypto_ahash_update(hp->md5_req);
1397}
1398
1399static int tcp_v4_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key,
1400 __be32 daddr, __be32 saddr, const struct tcphdr *th)
1401{
1402 struct tcp_md5sig_pool *hp;
1403 struct ahash_request *req;
1404
1405 hp = tcp_get_md5sig_pool();
1406 if (!hp)
1407 goto clear_hash_noput;
1408 req = hp->md5_req;
1409
1410 if (crypto_ahash_init(req))
1411 goto clear_hash;
1412 if (tcp_v4_md5_hash_headers(hp, daddr, saddr, th, th->doff << 2))
1413 goto clear_hash;
1414 if (tcp_md5_hash_key(hp, key))
1415 goto clear_hash;
1416 ahash_request_set_crypt(req, NULL, md5_hash, 0);
1417 if (crypto_ahash_final(req))
1418 goto clear_hash;
1419
1420 tcp_put_md5sig_pool();
1421 return 0;
1422
1423clear_hash:
1424 tcp_put_md5sig_pool();
1425clear_hash_noput:
1426 memset(md5_hash, 0, 16);
1427 return 1;
1428}
1429
1430int tcp_v4_md5_hash_skb(char *md5_hash, const struct tcp_md5sig_key *key,
1431 const struct sock *sk,
1432 const struct sk_buff *skb)
1433{
1434 struct tcp_md5sig_pool *hp;
1435 struct ahash_request *req;
1436 const struct tcphdr *th = tcp_hdr(skb);
1437 __be32 saddr, daddr;
1438
1439 if (sk) { /* valid for establish/request sockets */
1440 saddr = sk->sk_rcv_saddr;
1441 daddr = sk->sk_daddr;
1442 } else {
1443 const struct iphdr *iph = ip_hdr(skb);
1444 saddr = iph->saddr;
1445 daddr = iph->daddr;
1446 }
1447
1448 hp = tcp_get_md5sig_pool();
1449 if (!hp)
1450 goto clear_hash_noput;
1451 req = hp->md5_req;
1452
1453 if (crypto_ahash_init(req))
1454 goto clear_hash;
1455
1456 if (tcp_v4_md5_hash_headers(hp, daddr, saddr, th, skb->len))
1457 goto clear_hash;
1458 if (tcp_md5_hash_skb_data(hp, skb, th->doff << 2))
1459 goto clear_hash;
1460 if (tcp_md5_hash_key(hp, key))
1461 goto clear_hash;
1462 ahash_request_set_crypt(req, NULL, md5_hash, 0);
1463 if (crypto_ahash_final(req))
1464 goto clear_hash;
1465
1466 tcp_put_md5sig_pool();
1467 return 0;
1468
1469clear_hash:
1470 tcp_put_md5sig_pool();
1471clear_hash_noput:
1472 memset(md5_hash, 0, 16);
1473 return 1;
1474}
1475EXPORT_SYMBOL(tcp_v4_md5_hash_skb);
1476
1477#endif
1478
1479static void tcp_v4_init_req(struct request_sock *req,
1480 const struct sock *sk_listener,
1481 struct sk_buff *skb)
1482{
1483 struct inet_request_sock *ireq = inet_rsk(req);
1484 struct net *net = sock_net(sk_listener);
1485
1486 sk_rcv_saddr_set(req_to_sk(req), ip_hdr(skb)->daddr);
1487 sk_daddr_set(req_to_sk(req), ip_hdr(skb)->saddr);
1488 RCU_INIT_POINTER(ireq->ireq_opt, tcp_v4_save_options(net, skb));
1489}
1490
1491static struct dst_entry *tcp_v4_route_req(const struct sock *sk,
1492 struct sk_buff *skb,
1493 struct flowi *fl,
1494 struct request_sock *req)
1495{
1496 tcp_v4_init_req(req, sk, skb);
1497
1498 if (security_inet_conn_request(sk, skb, req))
1499 return NULL;
1500
1501 return inet_csk_route_req(sk, &fl->u.ip4, req);
1502}
1503
1504struct request_sock_ops tcp_request_sock_ops __read_mostly = {
1505 .family = PF_INET,
1506 .obj_size = sizeof(struct tcp_request_sock),
1507 .rtx_syn_ack = tcp_rtx_synack,
1508 .send_ack = tcp_v4_reqsk_send_ack,
1509 .destructor = tcp_v4_reqsk_destructor,
1510 .send_reset = tcp_v4_send_reset,
1511 .syn_ack_timeout = tcp_syn_ack_timeout,
1512};
1513
1514const struct tcp_request_sock_ops tcp_request_sock_ipv4_ops = {
1515 .mss_clamp = TCP_MSS_DEFAULT,
1516#ifdef CONFIG_TCP_MD5SIG
1517 .req_md5_lookup = tcp_v4_md5_lookup,
1518 .calc_md5_hash = tcp_v4_md5_hash_skb,
1519#endif
1520#ifdef CONFIG_SYN_COOKIES
1521 .cookie_init_seq = cookie_v4_init_sequence,
1522#endif
1523 .route_req = tcp_v4_route_req,
1524 .init_seq = tcp_v4_init_seq,
1525 .init_ts_off = tcp_v4_init_ts_off,
1526 .send_synack = tcp_v4_send_synack,
1527};
1528
1529int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
1530{
1531 /* Never answer to SYNs send to broadcast or multicast */
1532 if (skb_rtable(skb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
1533 goto drop;
1534
1535 return tcp_conn_request(&tcp_request_sock_ops,
1536 &tcp_request_sock_ipv4_ops, sk, skb);
1537
1538drop:
1539 tcp_listendrop(sk);
1540 return 0;
1541}
1542EXPORT_SYMBOL(tcp_v4_conn_request);
1543
1544
1545/*
1546 * The three way handshake has completed - we got a valid synack -
1547 * now create the new socket.
1548 */
1549struct sock *tcp_v4_syn_recv_sock(const struct sock *sk, struct sk_buff *skb,
1550 struct request_sock *req,
1551 struct dst_entry *dst,
1552 struct request_sock *req_unhash,
1553 bool *own_req)
1554{
1555 struct inet_request_sock *ireq;
1556 bool found_dup_sk = false;
1557 struct inet_sock *newinet;
1558 struct tcp_sock *newtp;
1559 struct sock *newsk;
1560#ifdef CONFIG_TCP_MD5SIG
1561 const union tcp_md5_addr *addr;
1562 struct tcp_md5sig_key *key;
1563 int l3index;
1564#endif
1565 struct ip_options_rcu *inet_opt;
1566
1567 if (sk_acceptq_is_full(sk))
1568 goto exit_overflow;
1569
1570 newsk = tcp_create_openreq_child(sk, req, skb);
1571 if (!newsk)
1572 goto exit_nonewsk;
1573
1574 newsk->sk_gso_type = SKB_GSO_TCPV4;
1575 inet_sk_rx_dst_set(newsk, skb);
1576
1577 newtp = tcp_sk(newsk);
1578 newinet = inet_sk(newsk);
1579 ireq = inet_rsk(req);
1580 sk_daddr_set(newsk, ireq->ir_rmt_addr);
1581 sk_rcv_saddr_set(newsk, ireq->ir_loc_addr);
1582 newsk->sk_bound_dev_if = ireq->ir_iif;
1583 newinet->inet_saddr = ireq->ir_loc_addr;
1584 inet_opt = rcu_dereference(ireq->ireq_opt);
1585 RCU_INIT_POINTER(newinet->inet_opt, inet_opt);
1586 newinet->mc_index = inet_iif(skb);
1587 newinet->mc_ttl = ip_hdr(skb)->ttl;
1588 newinet->rcv_tos = ip_hdr(skb)->tos;
1589 inet_csk(newsk)->icsk_ext_hdr_len = 0;
1590 if (inet_opt)
1591 inet_csk(newsk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
1592 newinet->inet_id = get_random_u16();
1593
1594 /* Set ToS of the new socket based upon the value of incoming SYN.
1595 * ECT bits are set later in tcp_init_transfer().
1596 */
1597 if (READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_reflect_tos))
1598 newinet->tos = tcp_rsk(req)->syn_tos & ~INET_ECN_MASK;
1599
1600 if (!dst) {
1601 dst = inet_csk_route_child_sock(sk, newsk, req);
1602 if (!dst)
1603 goto put_and_exit;
1604 } else {
1605 /* syncookie case : see end of cookie_v4_check() */
1606 }
1607 sk_setup_caps(newsk, dst);
1608
1609 tcp_ca_openreq_child(newsk, dst);
1610
1611 tcp_sync_mss(newsk, dst_mtu(dst));
1612 newtp->advmss = tcp_mss_clamp(tcp_sk(sk), dst_metric_advmss(dst));
1613
1614 tcp_initialize_rcv_mss(newsk);
1615
1616#ifdef CONFIG_TCP_MD5SIG
1617 l3index = l3mdev_master_ifindex_by_index(sock_net(sk), ireq->ir_iif);
1618 /* Copy over the MD5 key from the original socket */
1619 addr = (union tcp_md5_addr *)&newinet->inet_daddr;
1620 key = tcp_md5_do_lookup(sk, l3index, addr, AF_INET);
1621 if (key) {
1622 if (tcp_md5_key_copy(newsk, addr, AF_INET, 32, l3index, key))
1623 goto put_and_exit;
1624 sk_gso_disable(newsk);
1625 }
1626#endif
1627
1628 if (__inet_inherit_port(sk, newsk) < 0)
1629 goto put_and_exit;
1630 *own_req = inet_ehash_nolisten(newsk, req_to_sk(req_unhash),
1631 &found_dup_sk);
1632 if (likely(*own_req)) {
1633 tcp_move_syn(newtp, req);
1634 ireq->ireq_opt = NULL;
1635 } else {
1636 newinet->inet_opt = NULL;
1637
1638 if (!req_unhash && found_dup_sk) {
1639 /* This code path should only be executed in the
1640 * syncookie case only
1641 */
1642 bh_unlock_sock(newsk);
1643 sock_put(newsk);
1644 newsk = NULL;
1645 }
1646 }
1647 return newsk;
1648
1649exit_overflow:
1650 NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
1651exit_nonewsk:
1652 dst_release(dst);
1653exit:
1654 tcp_listendrop(sk);
1655 return NULL;
1656put_and_exit:
1657 newinet->inet_opt = NULL;
1658 inet_csk_prepare_forced_close(newsk);
1659 tcp_done(newsk);
1660 goto exit;
1661}
1662EXPORT_SYMBOL(tcp_v4_syn_recv_sock);
1663
1664static struct sock *tcp_v4_cookie_check(struct sock *sk, struct sk_buff *skb)
1665{
1666#ifdef CONFIG_SYN_COOKIES
1667 const struct tcphdr *th = tcp_hdr(skb);
1668
1669 if (!th->syn)
1670 sk = cookie_v4_check(sk, skb);
1671#endif
1672 return sk;
1673}
1674
1675u16 tcp_v4_get_syncookie(struct sock *sk, struct iphdr *iph,
1676 struct tcphdr *th, u32 *cookie)
1677{
1678 u16 mss = 0;
1679#ifdef CONFIG_SYN_COOKIES
1680 mss = tcp_get_syncookie_mss(&tcp_request_sock_ops,
1681 &tcp_request_sock_ipv4_ops, sk, th);
1682 if (mss) {
1683 *cookie = __cookie_v4_init_sequence(iph, th, &mss);
1684 tcp_synq_overflow(sk);
1685 }
1686#endif
1687 return mss;
1688}
1689
1690INDIRECT_CALLABLE_DECLARE(struct dst_entry *ipv4_dst_check(struct dst_entry *,
1691 u32));
1692/* The socket must have it's spinlock held when we get
1693 * here, unless it is a TCP_LISTEN socket.
1694 *
1695 * We have a potential double-lock case here, so even when
1696 * doing backlog processing we use the BH locking scheme.
1697 * This is because we cannot sleep with the original spinlock
1698 * held.
1699 */
1700int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
1701{
1702 enum skb_drop_reason reason;
1703 struct sock *rsk;
1704
1705 if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
1706 struct dst_entry *dst;
1707
1708 dst = rcu_dereference_protected(sk->sk_rx_dst,
1709 lockdep_sock_is_held(sk));
1710
1711 sock_rps_save_rxhash(sk, skb);
1712 sk_mark_napi_id(sk, skb);
1713 if (dst) {
1714 if (sk->sk_rx_dst_ifindex != skb->skb_iif ||
1715 !INDIRECT_CALL_1(dst->ops->check, ipv4_dst_check,
1716 dst, 0)) {
1717 RCU_INIT_POINTER(sk->sk_rx_dst, NULL);
1718 dst_release(dst);
1719 }
1720 }
1721 tcp_rcv_established(sk, skb);
1722 return 0;
1723 }
1724
1725 reason = SKB_DROP_REASON_NOT_SPECIFIED;
1726 if (tcp_checksum_complete(skb))
1727 goto csum_err;
1728
1729 if (sk->sk_state == TCP_LISTEN) {
1730 struct sock *nsk = tcp_v4_cookie_check(sk, skb);
1731
1732 if (!nsk)
1733 goto discard;
1734 if (nsk != sk) {
1735 if (tcp_child_process(sk, nsk, skb)) {
1736 rsk = nsk;
1737 goto reset;
1738 }
1739 return 0;
1740 }
1741 } else
1742 sock_rps_save_rxhash(sk, skb);
1743
1744 if (tcp_rcv_state_process(sk, skb)) {
1745 rsk = sk;
1746 goto reset;
1747 }
1748 return 0;
1749
1750reset:
1751 tcp_v4_send_reset(rsk, skb);
1752discard:
1753 kfree_skb_reason(skb, reason);
1754 /* Be careful here. If this function gets more complicated and
1755 * gcc suffers from register pressure on the x86, sk (in %ebx)
1756 * might be destroyed here. This current version compiles correctly,
1757 * but you have been warned.
1758 */
1759 return 0;
1760
1761csum_err:
1762 reason = SKB_DROP_REASON_TCP_CSUM;
1763 trace_tcp_bad_csum(skb);
1764 TCP_INC_STATS(sock_net(sk), TCP_MIB_CSUMERRORS);
1765 TCP_INC_STATS(sock_net(sk), TCP_MIB_INERRS);
1766 goto discard;
1767}
1768EXPORT_SYMBOL(tcp_v4_do_rcv);
1769
1770int tcp_v4_early_demux(struct sk_buff *skb)
1771{
1772 struct net *net = dev_net(skb->dev);
1773 const struct iphdr *iph;
1774 const struct tcphdr *th;
1775 struct sock *sk;
1776
1777 if (skb->pkt_type != PACKET_HOST)
1778 return 0;
1779
1780 if (!pskb_may_pull(skb, skb_transport_offset(skb) + sizeof(struct tcphdr)))
1781 return 0;
1782
1783 iph = ip_hdr(skb);
1784 th = tcp_hdr(skb);
1785
1786 if (th->doff < sizeof(struct tcphdr) / 4)
1787 return 0;
1788
1789 sk = __inet_lookup_established(net, net->ipv4.tcp_death_row.hashinfo,
1790 iph->saddr, th->source,
1791 iph->daddr, ntohs(th->dest),
1792 skb->skb_iif, inet_sdif(skb));
1793 if (sk) {
1794 skb->sk = sk;
1795 skb->destructor = sock_edemux;
1796 if (sk_fullsock(sk)) {
1797 struct dst_entry *dst = rcu_dereference(sk->sk_rx_dst);
1798
1799 if (dst)
1800 dst = dst_check(dst, 0);
1801 if (dst &&
1802 sk->sk_rx_dst_ifindex == skb->skb_iif)
1803 skb_dst_set_noref(skb, dst);
1804 }
1805 }
1806 return 0;
1807}
1808
1809bool tcp_add_backlog(struct sock *sk, struct sk_buff *skb,
1810 enum skb_drop_reason *reason)
1811{
1812 u32 limit, tail_gso_size, tail_gso_segs;
1813 struct skb_shared_info *shinfo;
1814 const struct tcphdr *th;
1815 struct tcphdr *thtail;
1816 struct sk_buff *tail;
1817 unsigned int hdrlen;
1818 bool fragstolen;
1819 u32 gso_segs;
1820 u32 gso_size;
1821 int delta;
1822
1823 /* In case all data was pulled from skb frags (in __pskb_pull_tail()),
1824 * we can fix skb->truesize to its real value to avoid future drops.
1825 * This is valid because skb is not yet charged to the socket.
1826 * It has been noticed pure SACK packets were sometimes dropped
1827 * (if cooked by drivers without copybreak feature).
1828 */
1829 skb_condense(skb);
1830
1831 skb_dst_drop(skb);
1832
1833 if (unlikely(tcp_checksum_complete(skb))) {
1834 bh_unlock_sock(sk);
1835 trace_tcp_bad_csum(skb);
1836 *reason = SKB_DROP_REASON_TCP_CSUM;
1837 __TCP_INC_STATS(sock_net(sk), TCP_MIB_CSUMERRORS);
1838 __TCP_INC_STATS(sock_net(sk), TCP_MIB_INERRS);
1839 return true;
1840 }
1841
1842 /* Attempt coalescing to last skb in backlog, even if we are
1843 * above the limits.
1844 * This is okay because skb capacity is limited to MAX_SKB_FRAGS.
1845 */
1846 th = (const struct tcphdr *)skb->data;
1847 hdrlen = th->doff * 4;
1848
1849 tail = sk->sk_backlog.tail;
1850 if (!tail)
1851 goto no_coalesce;
1852 thtail = (struct tcphdr *)tail->data;
1853
1854 if (TCP_SKB_CB(tail)->end_seq != TCP_SKB_CB(skb)->seq ||
1855 TCP_SKB_CB(tail)->ip_dsfield != TCP_SKB_CB(skb)->ip_dsfield ||
1856 ((TCP_SKB_CB(tail)->tcp_flags |
1857 TCP_SKB_CB(skb)->tcp_flags) & (TCPHDR_SYN | TCPHDR_RST | TCPHDR_URG)) ||
1858 !((TCP_SKB_CB(tail)->tcp_flags &
1859 TCP_SKB_CB(skb)->tcp_flags) & TCPHDR_ACK) ||
1860 ((TCP_SKB_CB(tail)->tcp_flags ^
1861 TCP_SKB_CB(skb)->tcp_flags) & (TCPHDR_ECE | TCPHDR_CWR)) ||
1862#ifdef CONFIG_TLS_DEVICE
1863 tail->decrypted != skb->decrypted ||
1864#endif
1865 thtail->doff != th->doff ||
1866 memcmp(thtail + 1, th + 1, hdrlen - sizeof(*th)))
1867 goto no_coalesce;
1868
1869 __skb_pull(skb, hdrlen);
1870
1871 shinfo = skb_shinfo(skb);
1872 gso_size = shinfo->gso_size ?: skb->len;
1873 gso_segs = shinfo->gso_segs ?: 1;
1874
1875 shinfo = skb_shinfo(tail);
1876 tail_gso_size = shinfo->gso_size ?: (tail->len - hdrlen);
1877 tail_gso_segs = shinfo->gso_segs ?: 1;
1878
1879 if (skb_try_coalesce(tail, skb, &fragstolen, &delta)) {
1880 TCP_SKB_CB(tail)->end_seq = TCP_SKB_CB(skb)->end_seq;
1881
1882 if (likely(!before(TCP_SKB_CB(skb)->ack_seq, TCP_SKB_CB(tail)->ack_seq))) {
1883 TCP_SKB_CB(tail)->ack_seq = TCP_SKB_CB(skb)->ack_seq;
1884 thtail->window = th->window;
1885 }
1886
1887 /* We have to update both TCP_SKB_CB(tail)->tcp_flags and
1888 * thtail->fin, so that the fast path in tcp_rcv_established()
1889 * is not entered if we append a packet with a FIN.
1890 * SYN, RST, URG are not present.
1891 * ACK is set on both packets.
1892 * PSH : we do not really care in TCP stack,
1893 * at least for 'GRO' packets.
1894 */
1895 thtail->fin |= th->fin;
1896 TCP_SKB_CB(tail)->tcp_flags |= TCP_SKB_CB(skb)->tcp_flags;
1897
1898 if (TCP_SKB_CB(skb)->has_rxtstamp) {
1899 TCP_SKB_CB(tail)->has_rxtstamp = true;
1900 tail->tstamp = skb->tstamp;
1901 skb_hwtstamps(tail)->hwtstamp = skb_hwtstamps(skb)->hwtstamp;
1902 }
1903
1904 /* Not as strict as GRO. We only need to carry mss max value */
1905 shinfo->gso_size = max(gso_size, tail_gso_size);
1906 shinfo->gso_segs = min_t(u32, gso_segs + tail_gso_segs, 0xFFFF);
1907
1908 sk->sk_backlog.len += delta;
1909 __NET_INC_STATS(sock_net(sk),
1910 LINUX_MIB_TCPBACKLOGCOALESCE);
1911 kfree_skb_partial(skb, fragstolen);
1912 return false;
1913 }
1914 __skb_push(skb, hdrlen);
1915
1916no_coalesce:
1917 limit = (u32)READ_ONCE(sk->sk_rcvbuf) + (u32)(READ_ONCE(sk->sk_sndbuf) >> 1);
1918
1919 /* Only socket owner can try to collapse/prune rx queues
1920 * to reduce memory overhead, so add a little headroom here.
1921 * Few sockets backlog are possibly concurrently non empty.
1922 */
1923 limit += 64 * 1024;
1924
1925 if (unlikely(sk_add_backlog(sk, skb, limit))) {
1926 bh_unlock_sock(sk);
1927 *reason = SKB_DROP_REASON_SOCKET_BACKLOG;
1928 __NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPBACKLOGDROP);
1929 return true;
1930 }
1931 return false;
1932}
1933EXPORT_SYMBOL(tcp_add_backlog);
1934
1935int tcp_filter(struct sock *sk, struct sk_buff *skb)
1936{
1937 struct tcphdr *th = (struct tcphdr *)skb->data;
1938
1939 return sk_filter_trim_cap(sk, skb, th->doff * 4);
1940}
1941EXPORT_SYMBOL(tcp_filter);
1942
1943static void tcp_v4_restore_cb(struct sk_buff *skb)
1944{
1945 memmove(IPCB(skb), &TCP_SKB_CB(skb)->header.h4,
1946 sizeof(struct inet_skb_parm));
1947}
1948
1949static void tcp_v4_fill_cb(struct sk_buff *skb, const struct iphdr *iph,
1950 const struct tcphdr *th)
1951{
1952 /* This is tricky : We move IPCB at its correct location into TCP_SKB_CB()
1953 * barrier() makes sure compiler wont play fool^Waliasing games.
1954 */
1955 memmove(&TCP_SKB_CB(skb)->header.h4, IPCB(skb),
1956 sizeof(struct inet_skb_parm));
1957 barrier();
1958
1959 TCP_SKB_CB(skb)->seq = ntohl(th->seq);
1960 TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
1961 skb->len - th->doff * 4);
1962 TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
1963 TCP_SKB_CB(skb)->tcp_flags = tcp_flag_byte(th);
1964 TCP_SKB_CB(skb)->tcp_tw_isn = 0;
1965 TCP_SKB_CB(skb)->ip_dsfield = ipv4_get_dsfield(iph);
1966 TCP_SKB_CB(skb)->sacked = 0;
1967 TCP_SKB_CB(skb)->has_rxtstamp =
1968 skb->tstamp || skb_hwtstamps(skb)->hwtstamp;
1969}
1970
1971/*
1972 * From tcp_input.c
1973 */
1974
1975int tcp_v4_rcv(struct sk_buff *skb)
1976{
1977 struct net *net = dev_net(skb->dev);
1978 enum skb_drop_reason drop_reason;
1979 int sdif = inet_sdif(skb);
1980 int dif = inet_iif(skb);
1981 const struct iphdr *iph;
1982 const struct tcphdr *th;
1983 bool refcounted;
1984 struct sock *sk;
1985 int ret;
1986
1987 drop_reason = SKB_DROP_REASON_NOT_SPECIFIED;
1988 if (skb->pkt_type != PACKET_HOST)
1989 goto discard_it;
1990
1991 /* Count it even if it's bad */
1992 __TCP_INC_STATS(net, TCP_MIB_INSEGS);
1993
1994 if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
1995 goto discard_it;
1996
1997 th = (const struct tcphdr *)skb->data;
1998
1999 if (unlikely(th->doff < sizeof(struct tcphdr) / 4)) {
2000 drop_reason = SKB_DROP_REASON_PKT_TOO_SMALL;
2001 goto bad_packet;
2002 }
2003 if (!pskb_may_pull(skb, th->doff * 4))
2004 goto discard_it;
2005
2006 /* An explanation is required here, I think.
2007 * Packet length and doff are validated by header prediction,
2008 * provided case of th->doff==0 is eliminated.
2009 * So, we defer the checks. */
2010
2011 if (skb_checksum_init(skb, IPPROTO_TCP, inet_compute_pseudo))
2012 goto csum_error;
2013
2014 th = (const struct tcphdr *)skb->data;
2015 iph = ip_hdr(skb);
2016lookup:
2017 sk = __inet_lookup_skb(net->ipv4.tcp_death_row.hashinfo,
2018 skb, __tcp_hdrlen(th), th->source,
2019 th->dest, sdif, &refcounted);
2020 if (!sk)
2021 goto no_tcp_socket;
2022
2023process:
2024 if (sk->sk_state == TCP_TIME_WAIT)
2025 goto do_time_wait;
2026
2027 if (sk->sk_state == TCP_NEW_SYN_RECV) {
2028 struct request_sock *req = inet_reqsk(sk);
2029 bool req_stolen = false;
2030 struct sock *nsk;
2031
2032 sk = req->rsk_listener;
2033 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
2034 drop_reason = SKB_DROP_REASON_XFRM_POLICY;
2035 else
2036 drop_reason = tcp_inbound_md5_hash(sk, skb,
2037 &iph->saddr, &iph->daddr,
2038 AF_INET, dif, sdif);
2039 if (unlikely(drop_reason)) {
2040 sk_drops_add(sk, skb);
2041 reqsk_put(req);
2042 goto discard_it;
2043 }
2044 if (tcp_checksum_complete(skb)) {
2045 reqsk_put(req);
2046 goto csum_error;
2047 }
2048 if (unlikely(sk->sk_state != TCP_LISTEN)) {
2049 nsk = reuseport_migrate_sock(sk, req_to_sk(req), skb);
2050 if (!nsk) {
2051 inet_csk_reqsk_queue_drop_and_put(sk, req);
2052 goto lookup;
2053 }
2054 sk = nsk;
2055 /* reuseport_migrate_sock() has already held one sk_refcnt
2056 * before returning.
2057 */
2058 } else {
2059 /* We own a reference on the listener, increase it again
2060 * as we might lose it too soon.
2061 */
2062 sock_hold(sk);
2063 }
2064 refcounted = true;
2065 nsk = NULL;
2066 if (!tcp_filter(sk, skb)) {
2067 th = (const struct tcphdr *)skb->data;
2068 iph = ip_hdr(skb);
2069 tcp_v4_fill_cb(skb, iph, th);
2070 nsk = tcp_check_req(sk, skb, req, false, &req_stolen);
2071 } else {
2072 drop_reason = SKB_DROP_REASON_SOCKET_FILTER;
2073 }
2074 if (!nsk) {
2075 reqsk_put(req);
2076 if (req_stolen) {
2077 /* Another cpu got exclusive access to req
2078 * and created a full blown socket.
2079 * Try to feed this packet to this socket
2080 * instead of discarding it.
2081 */
2082 tcp_v4_restore_cb(skb);
2083 sock_put(sk);
2084 goto lookup;
2085 }
2086 goto discard_and_relse;
2087 }
2088 nf_reset_ct(skb);
2089 if (nsk == sk) {
2090 reqsk_put(req);
2091 tcp_v4_restore_cb(skb);
2092 } else if (tcp_child_process(sk, nsk, skb)) {
2093 tcp_v4_send_reset(nsk, skb);
2094 goto discard_and_relse;
2095 } else {
2096 sock_put(sk);
2097 return 0;
2098 }
2099 }
2100
2101 if (static_branch_unlikely(&ip4_min_ttl)) {
2102 /* min_ttl can be changed concurrently from do_ip_setsockopt() */
2103 if (unlikely(iph->ttl < READ_ONCE(inet_sk(sk)->min_ttl))) {
2104 __NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP);
2105 goto discard_and_relse;
2106 }
2107 }
2108
2109 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb)) {
2110 drop_reason = SKB_DROP_REASON_XFRM_POLICY;
2111 goto discard_and_relse;
2112 }
2113
2114 drop_reason = tcp_inbound_md5_hash(sk, skb, &iph->saddr,
2115 &iph->daddr, AF_INET, dif, sdif);
2116 if (drop_reason)
2117 goto discard_and_relse;
2118
2119 nf_reset_ct(skb);
2120
2121 if (tcp_filter(sk, skb)) {
2122 drop_reason = SKB_DROP_REASON_SOCKET_FILTER;
2123 goto discard_and_relse;
2124 }
2125 th = (const struct tcphdr *)skb->data;
2126 iph = ip_hdr(skb);
2127 tcp_v4_fill_cb(skb, iph, th);
2128
2129 skb->dev = NULL;
2130
2131 if (sk->sk_state == TCP_LISTEN) {
2132 ret = tcp_v4_do_rcv(sk, skb);
2133 goto put_and_return;
2134 }
2135
2136 sk_incoming_cpu_update(sk);
2137
2138 bh_lock_sock_nested(sk);
2139 tcp_segs_in(tcp_sk(sk), skb);
2140 ret = 0;
2141 if (!sock_owned_by_user(sk)) {
2142 ret = tcp_v4_do_rcv(sk, skb);
2143 } else {
2144 if (tcp_add_backlog(sk, skb, &drop_reason))
2145 goto discard_and_relse;
2146 }
2147 bh_unlock_sock(sk);
2148
2149put_and_return:
2150 if (refcounted)
2151 sock_put(sk);
2152
2153 return ret;
2154
2155no_tcp_socket:
2156 drop_reason = SKB_DROP_REASON_NO_SOCKET;
2157 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
2158 goto discard_it;
2159
2160 tcp_v4_fill_cb(skb, iph, th);
2161
2162 if (tcp_checksum_complete(skb)) {
2163csum_error:
2164 drop_reason = SKB_DROP_REASON_TCP_CSUM;
2165 trace_tcp_bad_csum(skb);
2166 __TCP_INC_STATS(net, TCP_MIB_CSUMERRORS);
2167bad_packet:
2168 __TCP_INC_STATS(net, TCP_MIB_INERRS);
2169 } else {
2170 tcp_v4_send_reset(NULL, skb);
2171 }
2172
2173discard_it:
2174 SKB_DR_OR(drop_reason, NOT_SPECIFIED);
2175 /* Discard frame. */
2176 kfree_skb_reason(skb, drop_reason);
2177 return 0;
2178
2179discard_and_relse:
2180 sk_drops_add(sk, skb);
2181 if (refcounted)
2182 sock_put(sk);
2183 goto discard_it;
2184
2185do_time_wait:
2186 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
2187 drop_reason = SKB_DROP_REASON_XFRM_POLICY;
2188 inet_twsk_put(inet_twsk(sk));
2189 goto discard_it;
2190 }
2191
2192 tcp_v4_fill_cb(skb, iph, th);
2193
2194 if (tcp_checksum_complete(skb)) {
2195 inet_twsk_put(inet_twsk(sk));
2196 goto csum_error;
2197 }
2198 switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) {
2199 case TCP_TW_SYN: {
2200 struct sock *sk2 = inet_lookup_listener(net,
2201 net->ipv4.tcp_death_row.hashinfo,
2202 skb, __tcp_hdrlen(th),
2203 iph->saddr, th->source,
2204 iph->daddr, th->dest,
2205 inet_iif(skb),
2206 sdif);
2207 if (sk2) {
2208 inet_twsk_deschedule_put(inet_twsk(sk));
2209 sk = sk2;
2210 tcp_v4_restore_cb(skb);
2211 refcounted = false;
2212 goto process;
2213 }
2214 }
2215 /* to ACK */
2216 fallthrough;
2217 case TCP_TW_ACK:
2218 tcp_v4_timewait_ack(sk, skb);
2219 break;
2220 case TCP_TW_RST:
2221 tcp_v4_send_reset(sk, skb);
2222 inet_twsk_deschedule_put(inet_twsk(sk));
2223 goto discard_it;
2224 case TCP_TW_SUCCESS:;
2225 }
2226 goto discard_it;
2227}
2228
2229static struct timewait_sock_ops tcp_timewait_sock_ops = {
2230 .twsk_obj_size = sizeof(struct tcp_timewait_sock),
2231 .twsk_unique = tcp_twsk_unique,
2232 .twsk_destructor= tcp_twsk_destructor,
2233};
2234
2235void inet_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb)
2236{
2237 struct dst_entry *dst = skb_dst(skb);
2238
2239 if (dst && dst_hold_safe(dst)) {
2240 rcu_assign_pointer(sk->sk_rx_dst, dst);
2241 sk->sk_rx_dst_ifindex = skb->skb_iif;
2242 }
2243}
2244EXPORT_SYMBOL(inet_sk_rx_dst_set);
2245
2246const struct inet_connection_sock_af_ops ipv4_specific = {
2247 .queue_xmit = ip_queue_xmit,
2248 .send_check = tcp_v4_send_check,
2249 .rebuild_header = inet_sk_rebuild_header,
2250 .sk_rx_dst_set = inet_sk_rx_dst_set,
2251 .conn_request = tcp_v4_conn_request,
2252 .syn_recv_sock = tcp_v4_syn_recv_sock,
2253 .net_header_len = sizeof(struct iphdr),
2254 .setsockopt = ip_setsockopt,
2255 .getsockopt = ip_getsockopt,
2256 .addr2sockaddr = inet_csk_addr2sockaddr,
2257 .sockaddr_len = sizeof(struct sockaddr_in),
2258 .mtu_reduced = tcp_v4_mtu_reduced,
2259};
2260EXPORT_SYMBOL(ipv4_specific);
2261
2262#ifdef CONFIG_TCP_MD5SIG
2263static const struct tcp_sock_af_ops tcp_sock_ipv4_specific = {
2264 .md5_lookup = tcp_v4_md5_lookup,
2265 .calc_md5_hash = tcp_v4_md5_hash_skb,
2266 .md5_parse = tcp_v4_parse_md5_keys,
2267};
2268#endif
2269
2270/* NOTE: A lot of things set to zero explicitly by call to
2271 * sk_alloc() so need not be done here.
2272 */
2273static int tcp_v4_init_sock(struct sock *sk)
2274{
2275 struct inet_connection_sock *icsk = inet_csk(sk);
2276
2277 tcp_init_sock(sk);
2278
2279 icsk->icsk_af_ops = &ipv4_specific;
2280
2281#ifdef CONFIG_TCP_MD5SIG
2282 tcp_sk(sk)->af_specific = &tcp_sock_ipv4_specific;
2283#endif
2284
2285 return 0;
2286}
2287
2288void tcp_v4_destroy_sock(struct sock *sk)
2289{
2290 struct tcp_sock *tp = tcp_sk(sk);
2291
2292 trace_tcp_destroy_sock(sk);
2293
2294 tcp_clear_xmit_timers(sk);
2295
2296 tcp_cleanup_congestion_control(sk);
2297
2298 tcp_cleanup_ulp(sk);
2299
2300 /* Cleanup up the write buffer. */
2301 tcp_write_queue_purge(sk);
2302
2303 /* Check if we want to disable active TFO */
2304 tcp_fastopen_active_disable_ofo_check(sk);
2305
2306 /* Cleans up our, hopefully empty, out_of_order_queue. */
2307 skb_rbtree_purge(&tp->out_of_order_queue);
2308
2309#ifdef CONFIG_TCP_MD5SIG
2310 /* Clean up the MD5 key list, if any */
2311 if (tp->md5sig_info) {
2312 tcp_clear_md5_list(sk);
2313 kfree_rcu(rcu_dereference_protected(tp->md5sig_info, 1), rcu);
2314 tp->md5sig_info = NULL;
2315 static_branch_slow_dec_deferred(&tcp_md5_needed);
2316 }
2317#endif
2318
2319 /* Clean up a referenced TCP bind bucket. */
2320 if (inet_csk(sk)->icsk_bind_hash)
2321 inet_put_port(sk);
2322
2323 BUG_ON(rcu_access_pointer(tp->fastopen_rsk));
2324
2325 /* If socket is aborted during connect operation */
2326 tcp_free_fastopen_req(tp);
2327 tcp_fastopen_destroy_cipher(sk);
2328 tcp_saved_syn_free(tp);
2329
2330 sk_sockets_allocated_dec(sk);
2331}
2332EXPORT_SYMBOL(tcp_v4_destroy_sock);
2333
2334#ifdef CONFIG_PROC_FS
2335/* Proc filesystem TCP sock list dumping. */
2336
2337static unsigned short seq_file_family(const struct seq_file *seq);
2338
2339static bool seq_sk_match(struct seq_file *seq, const struct sock *sk)
2340{
2341 unsigned short family = seq_file_family(seq);
2342
2343 /* AF_UNSPEC is used as a match all */
2344 return ((family == AF_UNSPEC || family == sk->sk_family) &&
2345 net_eq(sock_net(sk), seq_file_net(seq)));
2346}
2347
2348/* Find a non empty bucket (starting from st->bucket)
2349 * and return the first sk from it.
2350 */
2351static void *listening_get_first(struct seq_file *seq)
2352{
2353 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo;
2354 struct tcp_iter_state *st = seq->private;
2355
2356 st->offset = 0;
2357 for (; st->bucket <= hinfo->lhash2_mask; st->bucket++) {
2358 struct inet_listen_hashbucket *ilb2;
2359 struct hlist_nulls_node *node;
2360 struct sock *sk;
2361
2362 ilb2 = &hinfo->lhash2[st->bucket];
2363 if (hlist_nulls_empty(&ilb2->nulls_head))
2364 continue;
2365
2366 spin_lock(&ilb2->lock);
2367 sk_nulls_for_each(sk, node, &ilb2->nulls_head) {
2368 if (seq_sk_match(seq, sk))
2369 return sk;
2370 }
2371 spin_unlock(&ilb2->lock);
2372 }
2373
2374 return NULL;
2375}
2376
2377/* Find the next sk of "cur" within the same bucket (i.e. st->bucket).
2378 * If "cur" is the last one in the st->bucket,
2379 * call listening_get_first() to return the first sk of the next
2380 * non empty bucket.
2381 */
2382static void *listening_get_next(struct seq_file *seq, void *cur)
2383{
2384 struct tcp_iter_state *st = seq->private;
2385 struct inet_listen_hashbucket *ilb2;
2386 struct hlist_nulls_node *node;
2387 struct inet_hashinfo *hinfo;
2388 struct sock *sk = cur;
2389
2390 ++st->num;
2391 ++st->offset;
2392
2393 sk = sk_nulls_next(sk);
2394 sk_nulls_for_each_from(sk, node) {
2395 if (seq_sk_match(seq, sk))
2396 return sk;
2397 }
2398
2399 hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo;
2400 ilb2 = &hinfo->lhash2[st->bucket];
2401 spin_unlock(&ilb2->lock);
2402 ++st->bucket;
2403 return listening_get_first(seq);
2404}
2405
2406static void *listening_get_idx(struct seq_file *seq, loff_t *pos)
2407{
2408 struct tcp_iter_state *st = seq->private;
2409 void *rc;
2410
2411 st->bucket = 0;
2412 st->offset = 0;
2413 rc = listening_get_first(seq);
2414
2415 while (rc && *pos) {
2416 rc = listening_get_next(seq, rc);
2417 --*pos;
2418 }
2419 return rc;
2420}
2421
2422static inline bool empty_bucket(struct inet_hashinfo *hinfo,
2423 const struct tcp_iter_state *st)
2424{
2425 return hlist_nulls_empty(&hinfo->ehash[st->bucket].chain);
2426}
2427
2428/*
2429 * Get first established socket starting from bucket given in st->bucket.
2430 * If st->bucket is zero, the very first socket in the hash is returned.
2431 */
2432static void *established_get_first(struct seq_file *seq)
2433{
2434 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo;
2435 struct tcp_iter_state *st = seq->private;
2436
2437 st->offset = 0;
2438 for (; st->bucket <= hinfo->ehash_mask; ++st->bucket) {
2439 struct sock *sk;
2440 struct hlist_nulls_node *node;
2441 spinlock_t *lock = inet_ehash_lockp(hinfo, st->bucket);
2442
2443 /* Lockless fast path for the common case of empty buckets */
2444 if (empty_bucket(hinfo, st))
2445 continue;
2446
2447 spin_lock_bh(lock);
2448 sk_nulls_for_each(sk, node, &hinfo->ehash[st->bucket].chain) {
2449 if (seq_sk_match(seq, sk))
2450 return sk;
2451 }
2452 spin_unlock_bh(lock);
2453 }
2454
2455 return NULL;
2456}
2457
2458static void *established_get_next(struct seq_file *seq, void *cur)
2459{
2460 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo;
2461 struct tcp_iter_state *st = seq->private;
2462 struct hlist_nulls_node *node;
2463 struct sock *sk = cur;
2464
2465 ++st->num;
2466 ++st->offset;
2467
2468 sk = sk_nulls_next(sk);
2469
2470 sk_nulls_for_each_from(sk, node) {
2471 if (seq_sk_match(seq, sk))
2472 return sk;
2473 }
2474
2475 spin_unlock_bh(inet_ehash_lockp(hinfo, st->bucket));
2476 ++st->bucket;
2477 return established_get_first(seq);
2478}
2479
2480static void *established_get_idx(struct seq_file *seq, loff_t pos)
2481{
2482 struct tcp_iter_state *st = seq->private;
2483 void *rc;
2484
2485 st->bucket = 0;
2486 rc = established_get_first(seq);
2487
2488 while (rc && pos) {
2489 rc = established_get_next(seq, rc);
2490 --pos;
2491 }
2492 return rc;
2493}
2494
2495static void *tcp_get_idx(struct seq_file *seq, loff_t pos)
2496{
2497 void *rc;
2498 struct tcp_iter_state *st = seq->private;
2499
2500 st->state = TCP_SEQ_STATE_LISTENING;
2501 rc = listening_get_idx(seq, &pos);
2502
2503 if (!rc) {
2504 st->state = TCP_SEQ_STATE_ESTABLISHED;
2505 rc = established_get_idx(seq, pos);
2506 }
2507
2508 return rc;
2509}
2510
2511static void *tcp_seek_last_pos(struct seq_file *seq)
2512{
2513 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo;
2514 struct tcp_iter_state *st = seq->private;
2515 int bucket = st->bucket;
2516 int offset = st->offset;
2517 int orig_num = st->num;
2518 void *rc = NULL;
2519
2520 switch (st->state) {
2521 case TCP_SEQ_STATE_LISTENING:
2522 if (st->bucket > hinfo->lhash2_mask)
2523 break;
2524 rc = listening_get_first(seq);
2525 while (offset-- && rc && bucket == st->bucket)
2526 rc = listening_get_next(seq, rc);
2527 if (rc)
2528 break;
2529 st->bucket = 0;
2530 st->state = TCP_SEQ_STATE_ESTABLISHED;
2531 fallthrough;
2532 case TCP_SEQ_STATE_ESTABLISHED:
2533 if (st->bucket > hinfo->ehash_mask)
2534 break;
2535 rc = established_get_first(seq);
2536 while (offset-- && rc && bucket == st->bucket)
2537 rc = established_get_next(seq, rc);
2538 }
2539
2540 st->num = orig_num;
2541
2542 return rc;
2543}
2544
2545void *tcp_seq_start(struct seq_file *seq, loff_t *pos)
2546{
2547 struct tcp_iter_state *st = seq->private;
2548 void *rc;
2549
2550 if (*pos && *pos == st->last_pos) {
2551 rc = tcp_seek_last_pos(seq);
2552 if (rc)
2553 goto out;
2554 }
2555
2556 st->state = TCP_SEQ_STATE_LISTENING;
2557 st->num = 0;
2558 st->bucket = 0;
2559 st->offset = 0;
2560 rc = *pos ? tcp_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
2561
2562out:
2563 st->last_pos = *pos;
2564 return rc;
2565}
2566EXPORT_SYMBOL(tcp_seq_start);
2567
2568void *tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2569{
2570 struct tcp_iter_state *st = seq->private;
2571 void *rc = NULL;
2572
2573 if (v == SEQ_START_TOKEN) {
2574 rc = tcp_get_idx(seq, 0);
2575 goto out;
2576 }
2577
2578 switch (st->state) {
2579 case TCP_SEQ_STATE_LISTENING:
2580 rc = listening_get_next(seq, v);
2581 if (!rc) {
2582 st->state = TCP_SEQ_STATE_ESTABLISHED;
2583 st->bucket = 0;
2584 st->offset = 0;
2585 rc = established_get_first(seq);
2586 }
2587 break;
2588 case TCP_SEQ_STATE_ESTABLISHED:
2589 rc = established_get_next(seq, v);
2590 break;
2591 }
2592out:
2593 ++*pos;
2594 st->last_pos = *pos;
2595 return rc;
2596}
2597EXPORT_SYMBOL(tcp_seq_next);
2598
2599void tcp_seq_stop(struct seq_file *seq, void *v)
2600{
2601 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo;
2602 struct tcp_iter_state *st = seq->private;
2603
2604 switch (st->state) {
2605 case TCP_SEQ_STATE_LISTENING:
2606 if (v != SEQ_START_TOKEN)
2607 spin_unlock(&hinfo->lhash2[st->bucket].lock);
2608 break;
2609 case TCP_SEQ_STATE_ESTABLISHED:
2610 if (v)
2611 spin_unlock_bh(inet_ehash_lockp(hinfo, st->bucket));
2612 break;
2613 }
2614}
2615EXPORT_SYMBOL(tcp_seq_stop);
2616
2617static void get_openreq4(const struct request_sock *req,
2618 struct seq_file *f, int i)
2619{
2620 const struct inet_request_sock *ireq = inet_rsk(req);
2621 long delta = req->rsk_timer.expires - jiffies;
2622
2623 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2624 " %02X %08X:%08X %02X:%08lX %08X %5u %8d %u %d %pK",
2625 i,
2626 ireq->ir_loc_addr,
2627 ireq->ir_num,
2628 ireq->ir_rmt_addr,
2629 ntohs(ireq->ir_rmt_port),
2630 TCP_SYN_RECV,
2631 0, 0, /* could print option size, but that is af dependent. */
2632 1, /* timers active (only the expire timer) */
2633 jiffies_delta_to_clock_t(delta),
2634 req->num_timeout,
2635 from_kuid_munged(seq_user_ns(f),
2636 sock_i_uid(req->rsk_listener)),
2637 0, /* non standard timer */
2638 0, /* open_requests have no inode */
2639 0,
2640 req);
2641}
2642
2643static void get_tcp4_sock(struct sock *sk, struct seq_file *f, int i)
2644{
2645 int timer_active;
2646 unsigned long timer_expires;
2647 const struct tcp_sock *tp = tcp_sk(sk);
2648 const struct inet_connection_sock *icsk = inet_csk(sk);
2649 const struct inet_sock *inet = inet_sk(sk);
2650 const struct fastopen_queue *fastopenq = &icsk->icsk_accept_queue.fastopenq;
2651 __be32 dest = inet->inet_daddr;
2652 __be32 src = inet->inet_rcv_saddr;
2653 __u16 destp = ntohs(inet->inet_dport);
2654 __u16 srcp = ntohs(inet->inet_sport);
2655 int rx_queue;
2656 int state;
2657
2658 if (icsk->icsk_pending == ICSK_TIME_RETRANS ||
2659 icsk->icsk_pending == ICSK_TIME_REO_TIMEOUT ||
2660 icsk->icsk_pending == ICSK_TIME_LOSS_PROBE) {
2661 timer_active = 1;
2662 timer_expires = icsk->icsk_timeout;
2663 } else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
2664 timer_active = 4;
2665 timer_expires = icsk->icsk_timeout;
2666 } else if (timer_pending(&sk->sk_timer)) {
2667 timer_active = 2;
2668 timer_expires = sk->sk_timer.expires;
2669 } else {
2670 timer_active = 0;
2671 timer_expires = jiffies;
2672 }
2673
2674 state = inet_sk_state_load(sk);
2675 if (state == TCP_LISTEN)
2676 rx_queue = READ_ONCE(sk->sk_ack_backlog);
2677 else
2678 /* Because we don't lock the socket,
2679 * we might find a transient negative value.
2680 */
2681 rx_queue = max_t(int, READ_ONCE(tp->rcv_nxt) -
2682 READ_ONCE(tp->copied_seq), 0);
2683
2684 seq_printf(f, "%4d: %08X:%04X %08X:%04X %02X %08X:%08X %02X:%08lX "
2685 "%08X %5u %8d %lu %d %pK %lu %lu %u %u %d",
2686 i, src, srcp, dest, destp, state,
2687 READ_ONCE(tp->write_seq) - tp->snd_una,
2688 rx_queue,
2689 timer_active,
2690 jiffies_delta_to_clock_t(timer_expires - jiffies),
2691 icsk->icsk_retransmits,
2692 from_kuid_munged(seq_user_ns(f), sock_i_uid(sk)),
2693 icsk->icsk_probes_out,
2694 sock_i_ino(sk),
2695 refcount_read(&sk->sk_refcnt), sk,
2696 jiffies_to_clock_t(icsk->icsk_rto),
2697 jiffies_to_clock_t(icsk->icsk_ack.ato),
2698 (icsk->icsk_ack.quick << 1) | inet_csk_in_pingpong_mode(sk),
2699 tcp_snd_cwnd(tp),
2700 state == TCP_LISTEN ?
2701 fastopenq->max_qlen :
2702 (tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh));
2703}
2704
2705static void get_timewait4_sock(const struct inet_timewait_sock *tw,
2706 struct seq_file *f, int i)
2707{
2708 long delta = tw->tw_timer.expires - jiffies;
2709 __be32 dest, src;
2710 __u16 destp, srcp;
2711
2712 dest = tw->tw_daddr;
2713 src = tw->tw_rcv_saddr;
2714 destp = ntohs(tw->tw_dport);
2715 srcp = ntohs(tw->tw_sport);
2716
2717 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2718 " %02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK",
2719 i, src, srcp, dest, destp, tw->tw_substate, 0, 0,
2720 3, jiffies_delta_to_clock_t(delta), 0, 0, 0, 0,
2721 refcount_read(&tw->tw_refcnt), tw);
2722}
2723
2724#define TMPSZ 150
2725
2726static int tcp4_seq_show(struct seq_file *seq, void *v)
2727{
2728 struct tcp_iter_state *st;
2729 struct sock *sk = v;
2730
2731 seq_setwidth(seq, TMPSZ - 1);
2732 if (v == SEQ_START_TOKEN) {
2733 seq_puts(seq, " sl local_address rem_address st tx_queue "
2734 "rx_queue tr tm->when retrnsmt uid timeout "
2735 "inode");
2736 goto out;
2737 }
2738 st = seq->private;
2739
2740 if (sk->sk_state == TCP_TIME_WAIT)
2741 get_timewait4_sock(v, seq, st->num);
2742 else if (sk->sk_state == TCP_NEW_SYN_RECV)
2743 get_openreq4(v, seq, st->num);
2744 else
2745 get_tcp4_sock(v, seq, st->num);
2746out:
2747 seq_pad(seq, '\n');
2748 return 0;
2749}
2750
2751#ifdef CONFIG_BPF_SYSCALL
2752struct bpf_tcp_iter_state {
2753 struct tcp_iter_state state;
2754 unsigned int cur_sk;
2755 unsigned int end_sk;
2756 unsigned int max_sk;
2757 struct sock **batch;
2758 bool st_bucket_done;
2759};
2760
2761struct bpf_iter__tcp {
2762 __bpf_md_ptr(struct bpf_iter_meta *, meta);
2763 __bpf_md_ptr(struct sock_common *, sk_common);
2764 uid_t uid __aligned(8);
2765};
2766
2767static int tcp_prog_seq_show(struct bpf_prog *prog, struct bpf_iter_meta *meta,
2768 struct sock_common *sk_common, uid_t uid)
2769{
2770 struct bpf_iter__tcp ctx;
2771
2772 meta->seq_num--; /* skip SEQ_START_TOKEN */
2773 ctx.meta = meta;
2774 ctx.sk_common = sk_common;
2775 ctx.uid = uid;
2776 return bpf_iter_run_prog(prog, &ctx);
2777}
2778
2779static void bpf_iter_tcp_put_batch(struct bpf_tcp_iter_state *iter)
2780{
2781 while (iter->cur_sk < iter->end_sk)
2782 sock_put(iter->batch[iter->cur_sk++]);
2783}
2784
2785static int bpf_iter_tcp_realloc_batch(struct bpf_tcp_iter_state *iter,
2786 unsigned int new_batch_sz)
2787{
2788 struct sock **new_batch;
2789
2790 new_batch = kvmalloc(sizeof(*new_batch) * new_batch_sz,
2791 GFP_USER | __GFP_NOWARN);
2792 if (!new_batch)
2793 return -ENOMEM;
2794
2795 bpf_iter_tcp_put_batch(iter);
2796 kvfree(iter->batch);
2797 iter->batch = new_batch;
2798 iter->max_sk = new_batch_sz;
2799
2800 return 0;
2801}
2802
2803static unsigned int bpf_iter_tcp_listening_batch(struct seq_file *seq,
2804 struct sock *start_sk)
2805{
2806 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo;
2807 struct bpf_tcp_iter_state *iter = seq->private;
2808 struct tcp_iter_state *st = &iter->state;
2809 struct hlist_nulls_node *node;
2810 unsigned int expected = 1;
2811 struct sock *sk;
2812
2813 sock_hold(start_sk);
2814 iter->batch[iter->end_sk++] = start_sk;
2815
2816 sk = sk_nulls_next(start_sk);
2817 sk_nulls_for_each_from(sk, node) {
2818 if (seq_sk_match(seq, sk)) {
2819 if (iter->end_sk < iter->max_sk) {
2820 sock_hold(sk);
2821 iter->batch[iter->end_sk++] = sk;
2822 }
2823 expected++;
2824 }
2825 }
2826 spin_unlock(&hinfo->lhash2[st->bucket].lock);
2827
2828 return expected;
2829}
2830
2831static unsigned int bpf_iter_tcp_established_batch(struct seq_file *seq,
2832 struct sock *start_sk)
2833{
2834 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo;
2835 struct bpf_tcp_iter_state *iter = seq->private;
2836 struct tcp_iter_state *st = &iter->state;
2837 struct hlist_nulls_node *node;
2838 unsigned int expected = 1;
2839 struct sock *sk;
2840
2841 sock_hold(start_sk);
2842 iter->batch[iter->end_sk++] = start_sk;
2843
2844 sk = sk_nulls_next(start_sk);
2845 sk_nulls_for_each_from(sk, node) {
2846 if (seq_sk_match(seq, sk)) {
2847 if (iter->end_sk < iter->max_sk) {
2848 sock_hold(sk);
2849 iter->batch[iter->end_sk++] = sk;
2850 }
2851 expected++;
2852 }
2853 }
2854 spin_unlock_bh(inet_ehash_lockp(hinfo, st->bucket));
2855
2856 return expected;
2857}
2858
2859static struct sock *bpf_iter_tcp_batch(struct seq_file *seq)
2860{
2861 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo;
2862 struct bpf_tcp_iter_state *iter = seq->private;
2863 struct tcp_iter_state *st = &iter->state;
2864 unsigned int expected;
2865 bool resized = false;
2866 struct sock *sk;
2867
2868 /* The st->bucket is done. Directly advance to the next
2869 * bucket instead of having the tcp_seek_last_pos() to skip
2870 * one by one in the current bucket and eventually find out
2871 * it has to advance to the next bucket.
2872 */
2873 if (iter->st_bucket_done) {
2874 st->offset = 0;
2875 st->bucket++;
2876 if (st->state == TCP_SEQ_STATE_LISTENING &&
2877 st->bucket > hinfo->lhash2_mask) {
2878 st->state = TCP_SEQ_STATE_ESTABLISHED;
2879 st->bucket = 0;
2880 }
2881 }
2882
2883again:
2884 /* Get a new batch */
2885 iter->cur_sk = 0;
2886 iter->end_sk = 0;
2887 iter->st_bucket_done = false;
2888
2889 sk = tcp_seek_last_pos(seq);
2890 if (!sk)
2891 return NULL; /* Done */
2892
2893 if (st->state == TCP_SEQ_STATE_LISTENING)
2894 expected = bpf_iter_tcp_listening_batch(seq, sk);
2895 else
2896 expected = bpf_iter_tcp_established_batch(seq, sk);
2897
2898 if (iter->end_sk == expected) {
2899 iter->st_bucket_done = true;
2900 return sk;
2901 }
2902
2903 if (!resized && !bpf_iter_tcp_realloc_batch(iter, expected * 3 / 2)) {
2904 resized = true;
2905 goto again;
2906 }
2907
2908 return sk;
2909}
2910
2911static void *bpf_iter_tcp_seq_start(struct seq_file *seq, loff_t *pos)
2912{
2913 /* bpf iter does not support lseek, so it always
2914 * continue from where it was stop()-ped.
2915 */
2916 if (*pos)
2917 return bpf_iter_tcp_batch(seq);
2918
2919 return SEQ_START_TOKEN;
2920}
2921
2922static void *bpf_iter_tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2923{
2924 struct bpf_tcp_iter_state *iter = seq->private;
2925 struct tcp_iter_state *st = &iter->state;
2926 struct sock *sk;
2927
2928 /* Whenever seq_next() is called, the iter->cur_sk is
2929 * done with seq_show(), so advance to the next sk in
2930 * the batch.
2931 */
2932 if (iter->cur_sk < iter->end_sk) {
2933 /* Keeping st->num consistent in tcp_iter_state.
2934 * bpf_iter_tcp does not use st->num.
2935 * meta.seq_num is used instead.
2936 */
2937 st->num++;
2938 /* Move st->offset to the next sk in the bucket such that
2939 * the future start() will resume at st->offset in
2940 * st->bucket. See tcp_seek_last_pos().
2941 */
2942 st->offset++;
2943 sock_put(iter->batch[iter->cur_sk++]);
2944 }
2945
2946 if (iter->cur_sk < iter->end_sk)
2947 sk = iter->batch[iter->cur_sk];
2948 else
2949 sk = bpf_iter_tcp_batch(seq);
2950
2951 ++*pos;
2952 /* Keeping st->last_pos consistent in tcp_iter_state.
2953 * bpf iter does not do lseek, so st->last_pos always equals to *pos.
2954 */
2955 st->last_pos = *pos;
2956 return sk;
2957}
2958
2959static int bpf_iter_tcp_seq_show(struct seq_file *seq, void *v)
2960{
2961 struct bpf_iter_meta meta;
2962 struct bpf_prog *prog;
2963 struct sock *sk = v;
2964 bool slow;
2965 uid_t uid;
2966 int ret;
2967
2968 if (v == SEQ_START_TOKEN)
2969 return 0;
2970
2971 if (sk_fullsock(sk))
2972 slow = lock_sock_fast(sk);
2973
2974 if (unlikely(sk_unhashed(sk))) {
2975 ret = SEQ_SKIP;
2976 goto unlock;
2977 }
2978
2979 if (sk->sk_state == TCP_TIME_WAIT) {
2980 uid = 0;
2981 } else if (sk->sk_state == TCP_NEW_SYN_RECV) {
2982 const struct request_sock *req = v;
2983
2984 uid = from_kuid_munged(seq_user_ns(seq),
2985 sock_i_uid(req->rsk_listener));
2986 } else {
2987 uid = from_kuid_munged(seq_user_ns(seq), sock_i_uid(sk));
2988 }
2989
2990 meta.seq = seq;
2991 prog = bpf_iter_get_info(&meta, false);
2992 ret = tcp_prog_seq_show(prog, &meta, v, uid);
2993
2994unlock:
2995 if (sk_fullsock(sk))
2996 unlock_sock_fast(sk, slow);
2997 return ret;
2998
2999}
3000
3001static void bpf_iter_tcp_seq_stop(struct seq_file *seq, void *v)
3002{
3003 struct bpf_tcp_iter_state *iter = seq->private;
3004 struct bpf_iter_meta meta;
3005 struct bpf_prog *prog;
3006
3007 if (!v) {
3008 meta.seq = seq;
3009 prog = bpf_iter_get_info(&meta, true);
3010 if (prog)
3011 (void)tcp_prog_seq_show(prog, &meta, v, 0);
3012 }
3013
3014 if (iter->cur_sk < iter->end_sk) {
3015 bpf_iter_tcp_put_batch(iter);
3016 iter->st_bucket_done = false;
3017 }
3018}
3019
3020static const struct seq_operations bpf_iter_tcp_seq_ops = {
3021 .show = bpf_iter_tcp_seq_show,
3022 .start = bpf_iter_tcp_seq_start,
3023 .next = bpf_iter_tcp_seq_next,
3024 .stop = bpf_iter_tcp_seq_stop,
3025};
3026#endif
3027static unsigned short seq_file_family(const struct seq_file *seq)
3028{
3029 const struct tcp_seq_afinfo *afinfo;
3030
3031#ifdef CONFIG_BPF_SYSCALL
3032 /* Iterated from bpf_iter. Let the bpf prog to filter instead. */
3033 if (seq->op == &bpf_iter_tcp_seq_ops)
3034 return AF_UNSPEC;
3035#endif
3036
3037 /* Iterated from proc fs */
3038 afinfo = pde_data(file_inode(seq->file));
3039 return afinfo->family;
3040}
3041
3042static const struct seq_operations tcp4_seq_ops = {
3043 .show = tcp4_seq_show,
3044 .start = tcp_seq_start,
3045 .next = tcp_seq_next,
3046 .stop = tcp_seq_stop,
3047};
3048
3049static struct tcp_seq_afinfo tcp4_seq_afinfo = {
3050 .family = AF_INET,
3051};
3052
3053static int __net_init tcp4_proc_init_net(struct net *net)
3054{
3055 if (!proc_create_net_data("tcp", 0444, net->proc_net, &tcp4_seq_ops,
3056 sizeof(struct tcp_iter_state), &tcp4_seq_afinfo))
3057 return -ENOMEM;
3058 return 0;
3059}
3060
3061static void __net_exit tcp4_proc_exit_net(struct net *net)
3062{
3063 remove_proc_entry("tcp", net->proc_net);
3064}
3065
3066static struct pernet_operations tcp4_net_ops = {
3067 .init = tcp4_proc_init_net,
3068 .exit = tcp4_proc_exit_net,
3069};
3070
3071int __init tcp4_proc_init(void)
3072{
3073 return register_pernet_subsys(&tcp4_net_ops);
3074}
3075
3076void tcp4_proc_exit(void)
3077{
3078 unregister_pernet_subsys(&tcp4_net_ops);
3079}
3080#endif /* CONFIG_PROC_FS */
3081
3082/* @wake is one when sk_stream_write_space() calls us.
3083 * This sends EPOLLOUT only if notsent_bytes is half the limit.
3084 * This mimics the strategy used in sock_def_write_space().
3085 */
3086bool tcp_stream_memory_free(const struct sock *sk, int wake)
3087{
3088 const struct tcp_sock *tp = tcp_sk(sk);
3089 u32 notsent_bytes = READ_ONCE(tp->write_seq) -
3090 READ_ONCE(tp->snd_nxt);
3091
3092 return (notsent_bytes << wake) < tcp_notsent_lowat(tp);
3093}
3094EXPORT_SYMBOL(tcp_stream_memory_free);
3095
3096struct proto tcp_prot = {
3097 .name = "TCP",
3098 .owner = THIS_MODULE,
3099 .close = tcp_close,
3100 .pre_connect = tcp_v4_pre_connect,
3101 .connect = tcp_v4_connect,
3102 .disconnect = tcp_disconnect,
3103 .accept = inet_csk_accept,
3104 .ioctl = tcp_ioctl,
3105 .init = tcp_v4_init_sock,
3106 .destroy = tcp_v4_destroy_sock,
3107 .shutdown = tcp_shutdown,
3108 .setsockopt = tcp_setsockopt,
3109 .getsockopt = tcp_getsockopt,
3110 .bpf_bypass_getsockopt = tcp_bpf_bypass_getsockopt,
3111 .keepalive = tcp_set_keepalive,
3112 .recvmsg = tcp_recvmsg,
3113 .sendmsg = tcp_sendmsg,
3114 .sendpage = tcp_sendpage,
3115 .backlog_rcv = tcp_v4_do_rcv,
3116 .release_cb = tcp_release_cb,
3117 .hash = inet_hash,
3118 .unhash = inet_unhash,
3119 .get_port = inet_csk_get_port,
3120 .put_port = inet_put_port,
3121#ifdef CONFIG_BPF_SYSCALL
3122 .psock_update_sk_prot = tcp_bpf_update_proto,
3123#endif
3124 .enter_memory_pressure = tcp_enter_memory_pressure,
3125 .leave_memory_pressure = tcp_leave_memory_pressure,
3126 .stream_memory_free = tcp_stream_memory_free,
3127 .sockets_allocated = &tcp_sockets_allocated,
3128 .orphan_count = &tcp_orphan_count,
3129
3130 .memory_allocated = &tcp_memory_allocated,
3131 .per_cpu_fw_alloc = &tcp_memory_per_cpu_fw_alloc,
3132
3133 .memory_pressure = &tcp_memory_pressure,
3134 .sysctl_mem = sysctl_tcp_mem,
3135 .sysctl_wmem_offset = offsetof(struct net, ipv4.sysctl_tcp_wmem),
3136 .sysctl_rmem_offset = offsetof(struct net, ipv4.sysctl_tcp_rmem),
3137 .max_header = MAX_TCP_HEADER,
3138 .obj_size = sizeof(struct tcp_sock),
3139 .slab_flags = SLAB_TYPESAFE_BY_RCU,
3140 .twsk_prot = &tcp_timewait_sock_ops,
3141 .rsk_prot = &tcp_request_sock_ops,
3142 .h.hashinfo = NULL,
3143 .no_autobind = true,
3144 .diag_destroy = tcp_abort,
3145};
3146EXPORT_SYMBOL(tcp_prot);
3147
3148static void __net_exit tcp_sk_exit(struct net *net)
3149{
3150 if (net->ipv4.tcp_congestion_control)
3151 bpf_module_put(net->ipv4.tcp_congestion_control,
3152 net->ipv4.tcp_congestion_control->owner);
3153}
3154
3155static void __net_init tcp_set_hashinfo(struct net *net)
3156{
3157 struct inet_hashinfo *hinfo;
3158 unsigned int ehash_entries;
3159 struct net *old_net;
3160
3161 if (net_eq(net, &init_net))
3162 goto fallback;
3163
3164 old_net = current->nsproxy->net_ns;
3165 ehash_entries = READ_ONCE(old_net->ipv4.sysctl_tcp_child_ehash_entries);
3166 if (!ehash_entries)
3167 goto fallback;
3168
3169 ehash_entries = roundup_pow_of_two(ehash_entries);
3170 hinfo = inet_pernet_hashinfo_alloc(&tcp_hashinfo, ehash_entries);
3171 if (!hinfo) {
3172 pr_warn("Failed to allocate TCP ehash (entries: %u) "
3173 "for a netns, fallback to the global one\n",
3174 ehash_entries);
3175fallback:
3176 hinfo = &tcp_hashinfo;
3177 ehash_entries = tcp_hashinfo.ehash_mask + 1;
3178 }
3179
3180 net->ipv4.tcp_death_row.hashinfo = hinfo;
3181 net->ipv4.tcp_death_row.sysctl_max_tw_buckets = ehash_entries / 2;
3182 net->ipv4.sysctl_max_syn_backlog = max(128U, ehash_entries / 128);
3183}
3184
3185static int __net_init tcp_sk_init(struct net *net)
3186{
3187 net->ipv4.sysctl_tcp_ecn = 2;
3188 net->ipv4.sysctl_tcp_ecn_fallback = 1;
3189
3190 net->ipv4.sysctl_tcp_base_mss = TCP_BASE_MSS;
3191 net->ipv4.sysctl_tcp_min_snd_mss = TCP_MIN_SND_MSS;
3192 net->ipv4.sysctl_tcp_probe_threshold = TCP_PROBE_THRESHOLD;
3193 net->ipv4.sysctl_tcp_probe_interval = TCP_PROBE_INTERVAL;
3194 net->ipv4.sysctl_tcp_mtu_probe_floor = TCP_MIN_SND_MSS;
3195
3196 net->ipv4.sysctl_tcp_keepalive_time = TCP_KEEPALIVE_TIME;
3197 net->ipv4.sysctl_tcp_keepalive_probes = TCP_KEEPALIVE_PROBES;
3198 net->ipv4.sysctl_tcp_keepalive_intvl = TCP_KEEPALIVE_INTVL;
3199
3200 net->ipv4.sysctl_tcp_syn_retries = TCP_SYN_RETRIES;
3201 net->ipv4.sysctl_tcp_synack_retries = TCP_SYNACK_RETRIES;
3202 net->ipv4.sysctl_tcp_syncookies = 1;
3203 net->ipv4.sysctl_tcp_reordering = TCP_FASTRETRANS_THRESH;
3204 net->ipv4.sysctl_tcp_retries1 = TCP_RETR1;
3205 net->ipv4.sysctl_tcp_retries2 = TCP_RETR2;
3206 net->ipv4.sysctl_tcp_orphan_retries = 0;
3207 net->ipv4.sysctl_tcp_fin_timeout = TCP_FIN_TIMEOUT;
3208 net->ipv4.sysctl_tcp_notsent_lowat = UINT_MAX;
3209 net->ipv4.sysctl_tcp_tw_reuse = 2;
3210 net->ipv4.sysctl_tcp_no_ssthresh_metrics_save = 1;
3211
3212 refcount_set(&net->ipv4.tcp_death_row.tw_refcount, 1);
3213 tcp_set_hashinfo(net);
3214
3215 net->ipv4.sysctl_tcp_sack = 1;
3216 net->ipv4.sysctl_tcp_window_scaling = 1;
3217 net->ipv4.sysctl_tcp_timestamps = 1;
3218 net->ipv4.sysctl_tcp_early_retrans = 3;
3219 net->ipv4.sysctl_tcp_recovery = TCP_RACK_LOSS_DETECTION;
3220 net->ipv4.sysctl_tcp_slow_start_after_idle = 1; /* By default, RFC2861 behavior. */
3221 net->ipv4.sysctl_tcp_retrans_collapse = 1;
3222 net->ipv4.sysctl_tcp_max_reordering = 300;
3223 net->ipv4.sysctl_tcp_dsack = 1;
3224 net->ipv4.sysctl_tcp_app_win = 31;
3225 net->ipv4.sysctl_tcp_adv_win_scale = 1;
3226 net->ipv4.sysctl_tcp_frto = 2;
3227 net->ipv4.sysctl_tcp_moderate_rcvbuf = 1;
3228 /* This limits the percentage of the congestion window which we
3229 * will allow a single TSO frame to consume. Building TSO frames
3230 * which are too large can cause TCP streams to be bursty.
3231 */
3232 net->ipv4.sysctl_tcp_tso_win_divisor = 3;
3233 /* Default TSQ limit of 16 TSO segments */
3234 net->ipv4.sysctl_tcp_limit_output_bytes = 16 * 65536;
3235
3236 /* rfc5961 challenge ack rate limiting, per net-ns, disabled by default. */
3237 net->ipv4.sysctl_tcp_challenge_ack_limit = INT_MAX;
3238
3239 net->ipv4.sysctl_tcp_min_tso_segs = 2;
3240 net->ipv4.sysctl_tcp_tso_rtt_log = 9; /* 2^9 = 512 usec */
3241 net->ipv4.sysctl_tcp_min_rtt_wlen = 300;
3242 net->ipv4.sysctl_tcp_autocorking = 1;
3243 net->ipv4.sysctl_tcp_invalid_ratelimit = HZ/2;
3244 net->ipv4.sysctl_tcp_pacing_ss_ratio = 200;
3245 net->ipv4.sysctl_tcp_pacing_ca_ratio = 120;
3246 if (net != &init_net) {
3247 memcpy(net->ipv4.sysctl_tcp_rmem,
3248 init_net.ipv4.sysctl_tcp_rmem,
3249 sizeof(init_net.ipv4.sysctl_tcp_rmem));
3250 memcpy(net->ipv4.sysctl_tcp_wmem,
3251 init_net.ipv4.sysctl_tcp_wmem,
3252 sizeof(init_net.ipv4.sysctl_tcp_wmem));
3253 }
3254 net->ipv4.sysctl_tcp_comp_sack_delay_ns = NSEC_PER_MSEC;
3255 net->ipv4.sysctl_tcp_comp_sack_slack_ns = 100 * NSEC_PER_USEC;
3256 net->ipv4.sysctl_tcp_comp_sack_nr = 44;
3257 net->ipv4.sysctl_tcp_fastopen = TFO_CLIENT_ENABLE;
3258 net->ipv4.sysctl_tcp_fastopen_blackhole_timeout = 0;
3259 atomic_set(&net->ipv4.tfo_active_disable_times, 0);
3260
3261 /* Set default values for PLB */
3262 net->ipv4.sysctl_tcp_plb_enabled = 0; /* Disabled by default */
3263 net->ipv4.sysctl_tcp_plb_idle_rehash_rounds = 3;
3264 net->ipv4.sysctl_tcp_plb_rehash_rounds = 12;
3265 net->ipv4.sysctl_tcp_plb_suspend_rto_sec = 60;
3266 /* Default congestion threshold for PLB to mark a round is 50% */
3267 net->ipv4.sysctl_tcp_plb_cong_thresh = (1 << TCP_PLB_SCALE) / 2;
3268
3269 /* Reno is always built in */
3270 if (!net_eq(net, &init_net) &&
3271 bpf_try_module_get(init_net.ipv4.tcp_congestion_control,
3272 init_net.ipv4.tcp_congestion_control->owner))
3273 net->ipv4.tcp_congestion_control = init_net.ipv4.tcp_congestion_control;
3274 else
3275 net->ipv4.tcp_congestion_control = &tcp_reno;
3276
3277 return 0;
3278}
3279
3280static void __net_exit tcp_sk_exit_batch(struct list_head *net_exit_list)
3281{
3282 struct net *net;
3283
3284 tcp_twsk_purge(net_exit_list, AF_INET);
3285
3286 list_for_each_entry(net, net_exit_list, exit_list) {
3287 inet_pernet_hashinfo_free(net->ipv4.tcp_death_row.hashinfo);
3288 WARN_ON_ONCE(!refcount_dec_and_test(&net->ipv4.tcp_death_row.tw_refcount));
3289 tcp_fastopen_ctx_destroy(net);
3290 }
3291}
3292
3293static struct pernet_operations __net_initdata tcp_sk_ops = {
3294 .init = tcp_sk_init,
3295 .exit = tcp_sk_exit,
3296 .exit_batch = tcp_sk_exit_batch,
3297};
3298
3299#if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS)
3300DEFINE_BPF_ITER_FUNC(tcp, struct bpf_iter_meta *meta,
3301 struct sock_common *sk_common, uid_t uid)
3302
3303#define INIT_BATCH_SZ 16
3304
3305static int bpf_iter_init_tcp(void *priv_data, struct bpf_iter_aux_info *aux)
3306{
3307 struct bpf_tcp_iter_state *iter = priv_data;
3308 int err;
3309
3310 err = bpf_iter_init_seq_net(priv_data, aux);
3311 if (err)
3312 return err;
3313
3314 err = bpf_iter_tcp_realloc_batch(iter, INIT_BATCH_SZ);
3315 if (err) {
3316 bpf_iter_fini_seq_net(priv_data);
3317 return err;
3318 }
3319
3320 return 0;
3321}
3322
3323static void bpf_iter_fini_tcp(void *priv_data)
3324{
3325 struct bpf_tcp_iter_state *iter = priv_data;
3326
3327 bpf_iter_fini_seq_net(priv_data);
3328 kvfree(iter->batch);
3329}
3330
3331static const struct bpf_iter_seq_info tcp_seq_info = {
3332 .seq_ops = &bpf_iter_tcp_seq_ops,
3333 .init_seq_private = bpf_iter_init_tcp,
3334 .fini_seq_private = bpf_iter_fini_tcp,
3335 .seq_priv_size = sizeof(struct bpf_tcp_iter_state),
3336};
3337
3338static const struct bpf_func_proto *
3339bpf_iter_tcp_get_func_proto(enum bpf_func_id func_id,
3340 const struct bpf_prog *prog)
3341{
3342 switch (func_id) {
3343 case BPF_FUNC_setsockopt:
3344 return &bpf_sk_setsockopt_proto;
3345 case BPF_FUNC_getsockopt:
3346 return &bpf_sk_getsockopt_proto;
3347 default:
3348 return NULL;
3349 }
3350}
3351
3352static struct bpf_iter_reg tcp_reg_info = {
3353 .target = "tcp",
3354 .ctx_arg_info_size = 1,
3355 .ctx_arg_info = {
3356 { offsetof(struct bpf_iter__tcp, sk_common),
3357 PTR_TO_BTF_ID_OR_NULL },
3358 },
3359 .get_func_proto = bpf_iter_tcp_get_func_proto,
3360 .seq_info = &tcp_seq_info,
3361};
3362
3363static void __init bpf_iter_register(void)
3364{
3365 tcp_reg_info.ctx_arg_info[0].btf_id = btf_sock_ids[BTF_SOCK_TYPE_SOCK_COMMON];
3366 if (bpf_iter_reg_target(&tcp_reg_info))
3367 pr_warn("Warning: could not register bpf iterator tcp\n");
3368}
3369
3370#endif
3371
3372void __init tcp_v4_init(void)
3373{
3374 int cpu, res;
3375
3376 for_each_possible_cpu(cpu) {
3377 struct sock *sk;
3378
3379 res = inet_ctl_sock_create(&sk, PF_INET, SOCK_RAW,
3380 IPPROTO_TCP, &init_net);
3381 if (res)
3382 panic("Failed to create the TCP control socket.\n");
3383 sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
3384
3385 /* Please enforce IP_DF and IPID==0 for RST and
3386 * ACK sent in SYN-RECV and TIME-WAIT state.
3387 */
3388 inet_sk(sk)->pmtudisc = IP_PMTUDISC_DO;
3389
3390 per_cpu(ipv4_tcp_sk, cpu) = sk;
3391 }
3392 if (register_pernet_subsys(&tcp_sk_ops))
3393 panic("Failed to create the TCP control socket.\n");
3394
3395#if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS)
3396 bpf_iter_register();
3397#endif
3398}
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * INET An implementation of the TCP/IP protocol suite for the LINUX
4 * operating system. INET is implemented using the BSD Socket
5 * interface as the means of communication with the user level.
6 *
7 * Implementation of the Transmission Control Protocol(TCP).
8 *
9 * IPv4 specific functions
10 *
11 * code split from:
12 * linux/ipv4/tcp.c
13 * linux/ipv4/tcp_input.c
14 * linux/ipv4/tcp_output.c
15 *
16 * See tcp.c for author information
17 */
18
19/*
20 * Changes:
21 * David S. Miller : New socket lookup architecture.
22 * This code is dedicated to John Dyson.
23 * David S. Miller : Change semantics of established hash,
24 * half is devoted to TIME_WAIT sockets
25 * and the rest go in the other half.
26 * Andi Kleen : Add support for syncookies and fixed
27 * some bugs: ip options weren't passed to
28 * the TCP layer, missed a check for an
29 * ACK bit.
30 * Andi Kleen : Implemented fast path mtu discovery.
31 * Fixed many serious bugs in the
32 * request_sock handling and moved
33 * most of it into the af independent code.
34 * Added tail drop and some other bugfixes.
35 * Added new listen semantics.
36 * Mike McLagan : Routing by source
37 * Juan Jose Ciarlante: ip_dynaddr bits
38 * Andi Kleen: various fixes.
39 * Vitaly E. Lavrov : Transparent proxy revived after year
40 * coma.
41 * Andi Kleen : Fix new listen.
42 * Andi Kleen : Fix accept error reporting.
43 * YOSHIFUJI Hideaki @USAGI and: Support IPV6_V6ONLY socket option, which
44 * Alexey Kuznetsov allow both IPv4 and IPv6 sockets to bind
45 * a single port at the same time.
46 */
47
48#define pr_fmt(fmt) "TCP: " fmt
49
50#include <linux/bottom_half.h>
51#include <linux/types.h>
52#include <linux/fcntl.h>
53#include <linux/module.h>
54#include <linux/random.h>
55#include <linux/cache.h>
56#include <linux/jhash.h>
57#include <linux/init.h>
58#include <linux/times.h>
59#include <linux/slab.h>
60#include <linux/sched.h>
61
62#include <net/net_namespace.h>
63#include <net/icmp.h>
64#include <net/inet_hashtables.h>
65#include <net/tcp.h>
66#include <net/transp_v6.h>
67#include <net/ipv6.h>
68#include <net/inet_common.h>
69#include <net/timewait_sock.h>
70#include <net/xfrm.h>
71#include <net/secure_seq.h>
72#include <net/busy_poll.h>
73
74#include <linux/inet.h>
75#include <linux/ipv6.h>
76#include <linux/stddef.h>
77#include <linux/proc_fs.h>
78#include <linux/seq_file.h>
79#include <linux/inetdevice.h>
80#include <linux/btf_ids.h>
81
82#include <crypto/hash.h>
83#include <linux/scatterlist.h>
84
85#include <trace/events/tcp.h>
86
87#ifdef CONFIG_TCP_MD5SIG
88static int tcp_v4_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key,
89 __be32 daddr, __be32 saddr, const struct tcphdr *th);
90#endif
91
92struct inet_hashinfo tcp_hashinfo;
93EXPORT_SYMBOL(tcp_hashinfo);
94
95static DEFINE_PER_CPU(struct sock *, ipv4_tcp_sk);
96
97static u32 tcp_v4_init_seq(const struct sk_buff *skb)
98{
99 return secure_tcp_seq(ip_hdr(skb)->daddr,
100 ip_hdr(skb)->saddr,
101 tcp_hdr(skb)->dest,
102 tcp_hdr(skb)->source);
103}
104
105static u32 tcp_v4_init_ts_off(const struct net *net, const struct sk_buff *skb)
106{
107 return secure_tcp_ts_off(net, ip_hdr(skb)->daddr, ip_hdr(skb)->saddr);
108}
109
110int tcp_twsk_unique(struct sock *sk, struct sock *sktw, void *twp)
111{
112 int reuse = READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_tw_reuse);
113 const struct inet_timewait_sock *tw = inet_twsk(sktw);
114 const struct tcp_timewait_sock *tcptw = tcp_twsk(sktw);
115 struct tcp_sock *tp = tcp_sk(sk);
116
117 if (reuse == 2) {
118 /* Still does not detect *everything* that goes through
119 * lo, since we require a loopback src or dst address
120 * or direct binding to 'lo' interface.
121 */
122 bool loopback = false;
123 if (tw->tw_bound_dev_if == LOOPBACK_IFINDEX)
124 loopback = true;
125#if IS_ENABLED(CONFIG_IPV6)
126 if (tw->tw_family == AF_INET6) {
127 if (ipv6_addr_loopback(&tw->tw_v6_daddr) ||
128 ipv6_addr_v4mapped_loopback(&tw->tw_v6_daddr) ||
129 ipv6_addr_loopback(&tw->tw_v6_rcv_saddr) ||
130 ipv6_addr_v4mapped_loopback(&tw->tw_v6_rcv_saddr))
131 loopback = true;
132 } else
133#endif
134 {
135 if (ipv4_is_loopback(tw->tw_daddr) ||
136 ipv4_is_loopback(tw->tw_rcv_saddr))
137 loopback = true;
138 }
139 if (!loopback)
140 reuse = 0;
141 }
142
143 /* With PAWS, it is safe from the viewpoint
144 of data integrity. Even without PAWS it is safe provided sequence
145 spaces do not overlap i.e. at data rates <= 80Mbit/sec.
146
147 Actually, the idea is close to VJ's one, only timestamp cache is
148 held not per host, but per port pair and TW bucket is used as state
149 holder.
150
151 If TW bucket has been already destroyed we fall back to VJ's scheme
152 and use initial timestamp retrieved from peer table.
153 */
154 if (tcptw->tw_ts_recent_stamp &&
155 (!twp || (reuse && time_after32(ktime_get_seconds(),
156 tcptw->tw_ts_recent_stamp)))) {
157 /* In case of repair and re-using TIME-WAIT sockets we still
158 * want to be sure that it is safe as above but honor the
159 * sequence numbers and time stamps set as part of the repair
160 * process.
161 *
162 * Without this check re-using a TIME-WAIT socket with TCP
163 * repair would accumulate a -1 on the repair assigned
164 * sequence number. The first time it is reused the sequence
165 * is -1, the second time -2, etc. This fixes that issue
166 * without appearing to create any others.
167 */
168 if (likely(!tp->repair)) {
169 u32 seq = tcptw->tw_snd_nxt + 65535 + 2;
170
171 if (!seq)
172 seq = 1;
173 WRITE_ONCE(tp->write_seq, seq);
174 tp->rx_opt.ts_recent = tcptw->tw_ts_recent;
175 tp->rx_opt.ts_recent_stamp = tcptw->tw_ts_recent_stamp;
176 }
177 sock_hold(sktw);
178 return 1;
179 }
180
181 return 0;
182}
183EXPORT_SYMBOL_GPL(tcp_twsk_unique);
184
185static int tcp_v4_pre_connect(struct sock *sk, struct sockaddr *uaddr,
186 int addr_len)
187{
188 /* This check is replicated from tcp_v4_connect() and intended to
189 * prevent BPF program called below from accessing bytes that are out
190 * of the bound specified by user in addr_len.
191 */
192 if (addr_len < sizeof(struct sockaddr_in))
193 return -EINVAL;
194
195 sock_owned_by_me(sk);
196
197 return BPF_CGROUP_RUN_PROG_INET4_CONNECT(sk, uaddr, &addr_len);
198}
199
200/* This will initiate an outgoing connection. */
201int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
202{
203 struct sockaddr_in *usin = (struct sockaddr_in *)uaddr;
204 struct inet_timewait_death_row *tcp_death_row;
205 struct inet_sock *inet = inet_sk(sk);
206 struct tcp_sock *tp = tcp_sk(sk);
207 struct ip_options_rcu *inet_opt;
208 struct net *net = sock_net(sk);
209 __be16 orig_sport, orig_dport;
210 __be32 daddr, nexthop;
211 struct flowi4 *fl4;
212 struct rtable *rt;
213 int err;
214
215 if (addr_len < sizeof(struct sockaddr_in))
216 return -EINVAL;
217
218 if (usin->sin_family != AF_INET)
219 return -EAFNOSUPPORT;
220
221 nexthop = daddr = usin->sin_addr.s_addr;
222 inet_opt = rcu_dereference_protected(inet->inet_opt,
223 lockdep_sock_is_held(sk));
224 if (inet_opt && inet_opt->opt.srr) {
225 if (!daddr)
226 return -EINVAL;
227 nexthop = inet_opt->opt.faddr;
228 }
229
230 orig_sport = inet->inet_sport;
231 orig_dport = usin->sin_port;
232 fl4 = &inet->cork.fl.u.ip4;
233 rt = ip_route_connect(fl4, nexthop, inet->inet_saddr,
234 sk->sk_bound_dev_if, IPPROTO_TCP, orig_sport,
235 orig_dport, sk);
236 if (IS_ERR(rt)) {
237 err = PTR_ERR(rt);
238 if (err == -ENETUNREACH)
239 IP_INC_STATS(net, IPSTATS_MIB_OUTNOROUTES);
240 return err;
241 }
242
243 if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) {
244 ip_rt_put(rt);
245 return -ENETUNREACH;
246 }
247
248 if (!inet_opt || !inet_opt->opt.srr)
249 daddr = fl4->daddr;
250
251 tcp_death_row = &sock_net(sk)->ipv4.tcp_death_row;
252
253 if (!inet->inet_saddr) {
254 err = inet_bhash2_update_saddr(sk, &fl4->saddr, AF_INET);
255 if (err) {
256 ip_rt_put(rt);
257 return err;
258 }
259 } else {
260 sk_rcv_saddr_set(sk, inet->inet_saddr);
261 }
262
263 if (tp->rx_opt.ts_recent_stamp && inet->inet_daddr != daddr) {
264 /* Reset inherited state */
265 tp->rx_opt.ts_recent = 0;
266 tp->rx_opt.ts_recent_stamp = 0;
267 if (likely(!tp->repair))
268 WRITE_ONCE(tp->write_seq, 0);
269 }
270
271 inet->inet_dport = usin->sin_port;
272 sk_daddr_set(sk, daddr);
273
274 inet_csk(sk)->icsk_ext_hdr_len = 0;
275 if (inet_opt)
276 inet_csk(sk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
277
278 tp->rx_opt.mss_clamp = TCP_MSS_DEFAULT;
279
280 /* Socket identity is still unknown (sport may be zero).
281 * However we set state to SYN-SENT and not releasing socket
282 * lock select source port, enter ourselves into the hash tables and
283 * complete initialization after this.
284 */
285 tcp_set_state(sk, TCP_SYN_SENT);
286 err = inet_hash_connect(tcp_death_row, sk);
287 if (err)
288 goto failure;
289
290 sk_set_txhash(sk);
291
292 rt = ip_route_newports(fl4, rt, orig_sport, orig_dport,
293 inet->inet_sport, inet->inet_dport, sk);
294 if (IS_ERR(rt)) {
295 err = PTR_ERR(rt);
296 rt = NULL;
297 goto failure;
298 }
299 tp->tcp_usec_ts = dst_tcp_usec_ts(&rt->dst);
300 /* OK, now commit destination to socket. */
301 sk->sk_gso_type = SKB_GSO_TCPV4;
302 sk_setup_caps(sk, &rt->dst);
303 rt = NULL;
304
305 if (likely(!tp->repair)) {
306 if (!tp->write_seq)
307 WRITE_ONCE(tp->write_seq,
308 secure_tcp_seq(inet->inet_saddr,
309 inet->inet_daddr,
310 inet->inet_sport,
311 usin->sin_port));
312 WRITE_ONCE(tp->tsoffset,
313 secure_tcp_ts_off(net, inet->inet_saddr,
314 inet->inet_daddr));
315 }
316
317 atomic_set(&inet->inet_id, get_random_u16());
318
319 if (tcp_fastopen_defer_connect(sk, &err))
320 return err;
321 if (err)
322 goto failure;
323
324 err = tcp_connect(sk);
325
326 if (err)
327 goto failure;
328
329 return 0;
330
331failure:
332 /*
333 * This unhashes the socket and releases the local port,
334 * if necessary.
335 */
336 tcp_set_state(sk, TCP_CLOSE);
337 inet_bhash2_reset_saddr(sk);
338 ip_rt_put(rt);
339 sk->sk_route_caps = 0;
340 inet->inet_dport = 0;
341 return err;
342}
343EXPORT_SYMBOL(tcp_v4_connect);
344
345/*
346 * This routine reacts to ICMP_FRAG_NEEDED mtu indications as defined in RFC1191.
347 * It can be called through tcp_release_cb() if socket was owned by user
348 * at the time tcp_v4_err() was called to handle ICMP message.
349 */
350void tcp_v4_mtu_reduced(struct sock *sk)
351{
352 struct inet_sock *inet = inet_sk(sk);
353 struct dst_entry *dst;
354 u32 mtu;
355
356 if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE))
357 return;
358 mtu = READ_ONCE(tcp_sk(sk)->mtu_info);
359 dst = inet_csk_update_pmtu(sk, mtu);
360 if (!dst)
361 return;
362
363 /* Something is about to be wrong... Remember soft error
364 * for the case, if this connection will not able to recover.
365 */
366 if (mtu < dst_mtu(dst) && ip_dont_fragment(sk, dst))
367 WRITE_ONCE(sk->sk_err_soft, EMSGSIZE);
368
369 mtu = dst_mtu(dst);
370
371 if (inet->pmtudisc != IP_PMTUDISC_DONT &&
372 ip_sk_accept_pmtu(sk) &&
373 inet_csk(sk)->icsk_pmtu_cookie > mtu) {
374 tcp_sync_mss(sk, mtu);
375
376 /* Resend the TCP packet because it's
377 * clear that the old packet has been
378 * dropped. This is the new "fast" path mtu
379 * discovery.
380 */
381 tcp_simple_retransmit(sk);
382 } /* else let the usual retransmit timer handle it */
383}
384EXPORT_SYMBOL(tcp_v4_mtu_reduced);
385
386static void do_redirect(struct sk_buff *skb, struct sock *sk)
387{
388 struct dst_entry *dst = __sk_dst_check(sk, 0);
389
390 if (dst)
391 dst->ops->redirect(dst, sk, skb);
392}
393
394
395/* handle ICMP messages on TCP_NEW_SYN_RECV request sockets */
396void tcp_req_err(struct sock *sk, u32 seq, bool abort)
397{
398 struct request_sock *req = inet_reqsk(sk);
399 struct net *net = sock_net(sk);
400
401 /* ICMPs are not backlogged, hence we cannot get
402 * an established socket here.
403 */
404 if (seq != tcp_rsk(req)->snt_isn) {
405 __NET_INC_STATS(net, LINUX_MIB_OUTOFWINDOWICMPS);
406 } else if (abort) {
407 /*
408 * Still in SYN_RECV, just remove it silently.
409 * There is no good way to pass the error to the newly
410 * created socket, and POSIX does not want network
411 * errors returned from accept().
412 */
413 inet_csk_reqsk_queue_drop(req->rsk_listener, req);
414 tcp_listendrop(req->rsk_listener);
415 }
416 reqsk_put(req);
417}
418EXPORT_SYMBOL(tcp_req_err);
419
420/* TCP-LD (RFC 6069) logic */
421void tcp_ld_RTO_revert(struct sock *sk, u32 seq)
422{
423 struct inet_connection_sock *icsk = inet_csk(sk);
424 struct tcp_sock *tp = tcp_sk(sk);
425 struct sk_buff *skb;
426 s32 remaining;
427 u32 delta_us;
428
429 if (sock_owned_by_user(sk))
430 return;
431
432 if (seq != tp->snd_una || !icsk->icsk_retransmits ||
433 !icsk->icsk_backoff)
434 return;
435
436 skb = tcp_rtx_queue_head(sk);
437 if (WARN_ON_ONCE(!skb))
438 return;
439
440 icsk->icsk_backoff--;
441 icsk->icsk_rto = tp->srtt_us ? __tcp_set_rto(tp) : TCP_TIMEOUT_INIT;
442 icsk->icsk_rto = inet_csk_rto_backoff(icsk, TCP_RTO_MAX);
443
444 tcp_mstamp_refresh(tp);
445 delta_us = (u32)(tp->tcp_mstamp - tcp_skb_timestamp_us(skb));
446 remaining = icsk->icsk_rto - usecs_to_jiffies(delta_us);
447
448 if (remaining > 0) {
449 inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
450 remaining, TCP_RTO_MAX);
451 } else {
452 /* RTO revert clocked out retransmission.
453 * Will retransmit now.
454 */
455 tcp_retransmit_timer(sk);
456 }
457}
458EXPORT_SYMBOL(tcp_ld_RTO_revert);
459
460/*
461 * This routine is called by the ICMP module when it gets some
462 * sort of error condition. If err < 0 then the socket should
463 * be closed and the error returned to the user. If err > 0
464 * it's just the icmp type << 8 | icmp code. After adjustment
465 * header points to the first 8 bytes of the tcp header. We need
466 * to find the appropriate port.
467 *
468 * The locking strategy used here is very "optimistic". When
469 * someone else accesses the socket the ICMP is just dropped
470 * and for some paths there is no check at all.
471 * A more general error queue to queue errors for later handling
472 * is probably better.
473 *
474 */
475
476int tcp_v4_err(struct sk_buff *skb, u32 info)
477{
478 const struct iphdr *iph = (const struct iphdr *)skb->data;
479 struct tcphdr *th = (struct tcphdr *)(skb->data + (iph->ihl << 2));
480 struct tcp_sock *tp;
481 const int type = icmp_hdr(skb)->type;
482 const int code = icmp_hdr(skb)->code;
483 struct sock *sk;
484 struct request_sock *fastopen;
485 u32 seq, snd_una;
486 int err;
487 struct net *net = dev_net(skb->dev);
488
489 sk = __inet_lookup_established(net, net->ipv4.tcp_death_row.hashinfo,
490 iph->daddr, th->dest, iph->saddr,
491 ntohs(th->source), inet_iif(skb), 0);
492 if (!sk) {
493 __ICMP_INC_STATS(net, ICMP_MIB_INERRORS);
494 return -ENOENT;
495 }
496 if (sk->sk_state == TCP_TIME_WAIT) {
497 /* To increase the counter of ignored icmps for TCP-AO */
498 tcp_ao_ignore_icmp(sk, AF_INET, type, code);
499 inet_twsk_put(inet_twsk(sk));
500 return 0;
501 }
502 seq = ntohl(th->seq);
503 if (sk->sk_state == TCP_NEW_SYN_RECV) {
504 tcp_req_err(sk, seq, type == ICMP_PARAMETERPROB ||
505 type == ICMP_TIME_EXCEEDED ||
506 (type == ICMP_DEST_UNREACH &&
507 (code == ICMP_NET_UNREACH ||
508 code == ICMP_HOST_UNREACH)));
509 return 0;
510 }
511
512 if (tcp_ao_ignore_icmp(sk, AF_INET, type, code)) {
513 sock_put(sk);
514 return 0;
515 }
516
517 bh_lock_sock(sk);
518 /* If too many ICMPs get dropped on busy
519 * servers this needs to be solved differently.
520 * We do take care of PMTU discovery (RFC1191) special case :
521 * we can receive locally generated ICMP messages while socket is held.
522 */
523 if (sock_owned_by_user(sk)) {
524 if (!(type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED))
525 __NET_INC_STATS(net, LINUX_MIB_LOCKDROPPEDICMPS);
526 }
527 if (sk->sk_state == TCP_CLOSE)
528 goto out;
529
530 if (static_branch_unlikely(&ip4_min_ttl)) {
531 /* min_ttl can be changed concurrently from do_ip_setsockopt() */
532 if (unlikely(iph->ttl < READ_ONCE(inet_sk(sk)->min_ttl))) {
533 __NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP);
534 goto out;
535 }
536 }
537
538 tp = tcp_sk(sk);
539 /* XXX (TFO) - tp->snd_una should be ISN (tcp_create_openreq_child() */
540 fastopen = rcu_dereference(tp->fastopen_rsk);
541 snd_una = fastopen ? tcp_rsk(fastopen)->snt_isn : tp->snd_una;
542 if (sk->sk_state != TCP_LISTEN &&
543 !between(seq, snd_una, tp->snd_nxt)) {
544 __NET_INC_STATS(net, LINUX_MIB_OUTOFWINDOWICMPS);
545 goto out;
546 }
547
548 switch (type) {
549 case ICMP_REDIRECT:
550 if (!sock_owned_by_user(sk))
551 do_redirect(skb, sk);
552 goto out;
553 case ICMP_SOURCE_QUENCH:
554 /* Just silently ignore these. */
555 goto out;
556 case ICMP_PARAMETERPROB:
557 err = EPROTO;
558 break;
559 case ICMP_DEST_UNREACH:
560 if (code > NR_ICMP_UNREACH)
561 goto out;
562
563 if (code == ICMP_FRAG_NEEDED) { /* PMTU discovery (RFC1191) */
564 /* We are not interested in TCP_LISTEN and open_requests
565 * (SYN-ACKs send out by Linux are always <576bytes so
566 * they should go through unfragmented).
567 */
568 if (sk->sk_state == TCP_LISTEN)
569 goto out;
570
571 WRITE_ONCE(tp->mtu_info, info);
572 if (!sock_owned_by_user(sk)) {
573 tcp_v4_mtu_reduced(sk);
574 } else {
575 if (!test_and_set_bit(TCP_MTU_REDUCED_DEFERRED, &sk->sk_tsq_flags))
576 sock_hold(sk);
577 }
578 goto out;
579 }
580
581 err = icmp_err_convert[code].errno;
582 /* check if this ICMP message allows revert of backoff.
583 * (see RFC 6069)
584 */
585 if (!fastopen &&
586 (code == ICMP_NET_UNREACH || code == ICMP_HOST_UNREACH))
587 tcp_ld_RTO_revert(sk, seq);
588 break;
589 case ICMP_TIME_EXCEEDED:
590 err = EHOSTUNREACH;
591 break;
592 default:
593 goto out;
594 }
595
596 switch (sk->sk_state) {
597 case TCP_SYN_SENT:
598 case TCP_SYN_RECV:
599 /* Only in fast or simultaneous open. If a fast open socket is
600 * already accepted it is treated as a connected one below.
601 */
602 if (fastopen && !fastopen->sk)
603 break;
604
605 ip_icmp_error(sk, skb, err, th->dest, info, (u8 *)th);
606
607 if (!sock_owned_by_user(sk)) {
608 WRITE_ONCE(sk->sk_err, err);
609
610 sk_error_report(sk);
611
612 tcp_done(sk);
613 } else {
614 WRITE_ONCE(sk->sk_err_soft, err);
615 }
616 goto out;
617 }
618
619 /* If we've already connected we will keep trying
620 * until we time out, or the user gives up.
621 *
622 * rfc1122 4.2.3.9 allows to consider as hard errors
623 * only PROTO_UNREACH and PORT_UNREACH (well, FRAG_FAILED too,
624 * but it is obsoleted by pmtu discovery).
625 *
626 * Note, that in modern internet, where routing is unreliable
627 * and in each dark corner broken firewalls sit, sending random
628 * errors ordered by their masters even this two messages finally lose
629 * their original sense (even Linux sends invalid PORT_UNREACHs)
630 *
631 * Now we are in compliance with RFCs.
632 * --ANK (980905)
633 */
634
635 if (!sock_owned_by_user(sk) &&
636 inet_test_bit(RECVERR, sk)) {
637 WRITE_ONCE(sk->sk_err, err);
638 sk_error_report(sk);
639 } else { /* Only an error on timeout */
640 WRITE_ONCE(sk->sk_err_soft, err);
641 }
642
643out:
644 bh_unlock_sock(sk);
645 sock_put(sk);
646 return 0;
647}
648
649void __tcp_v4_send_check(struct sk_buff *skb, __be32 saddr, __be32 daddr)
650{
651 struct tcphdr *th = tcp_hdr(skb);
652
653 th->check = ~tcp_v4_check(skb->len, saddr, daddr, 0);
654 skb->csum_start = skb_transport_header(skb) - skb->head;
655 skb->csum_offset = offsetof(struct tcphdr, check);
656}
657
658/* This routine computes an IPv4 TCP checksum. */
659void tcp_v4_send_check(struct sock *sk, struct sk_buff *skb)
660{
661 const struct inet_sock *inet = inet_sk(sk);
662
663 __tcp_v4_send_check(skb, inet->inet_saddr, inet->inet_daddr);
664}
665EXPORT_SYMBOL(tcp_v4_send_check);
666
667#define REPLY_OPTIONS_LEN (MAX_TCP_OPTION_SPACE / sizeof(__be32))
668
669static bool tcp_v4_ao_sign_reset(const struct sock *sk, struct sk_buff *skb,
670 const struct tcp_ao_hdr *aoh,
671 struct ip_reply_arg *arg, struct tcphdr *reply,
672 __be32 reply_options[REPLY_OPTIONS_LEN])
673{
674#ifdef CONFIG_TCP_AO
675 int sdif = tcp_v4_sdif(skb);
676 int dif = inet_iif(skb);
677 int l3index = sdif ? dif : 0;
678 bool allocated_traffic_key;
679 struct tcp_ao_key *key;
680 char *traffic_key;
681 bool drop = true;
682 u32 ao_sne = 0;
683 u8 keyid;
684
685 rcu_read_lock();
686 if (tcp_ao_prepare_reset(sk, skb, aoh, l3index, ntohl(reply->seq),
687 &key, &traffic_key, &allocated_traffic_key,
688 &keyid, &ao_sne))
689 goto out;
690
691 reply_options[0] = htonl((TCPOPT_AO << 24) | (tcp_ao_len(key) << 16) |
692 (aoh->rnext_keyid << 8) | keyid);
693 arg->iov[0].iov_len += tcp_ao_len_aligned(key);
694 reply->doff = arg->iov[0].iov_len / 4;
695
696 if (tcp_ao_hash_hdr(AF_INET, (char *)&reply_options[1],
697 key, traffic_key,
698 (union tcp_ao_addr *)&ip_hdr(skb)->saddr,
699 (union tcp_ao_addr *)&ip_hdr(skb)->daddr,
700 reply, ao_sne))
701 goto out;
702 drop = false;
703out:
704 rcu_read_unlock();
705 if (allocated_traffic_key)
706 kfree(traffic_key);
707 return drop;
708#else
709 return true;
710#endif
711}
712
713/*
714 * This routine will send an RST to the other tcp.
715 *
716 * Someone asks: why I NEVER use socket parameters (TOS, TTL etc.)
717 * for reset.
718 * Answer: if a packet caused RST, it is not for a socket
719 * existing in our system, if it is matched to a socket,
720 * it is just duplicate segment or bug in other side's TCP.
721 * So that we build reply only basing on parameters
722 * arrived with segment.
723 * Exception: precedence violation. We do not implement it in any case.
724 */
725
726static void tcp_v4_send_reset(const struct sock *sk, struct sk_buff *skb)
727{
728 const struct tcphdr *th = tcp_hdr(skb);
729 struct {
730 struct tcphdr th;
731 __be32 opt[REPLY_OPTIONS_LEN];
732 } rep;
733 const __u8 *md5_hash_location = NULL;
734 const struct tcp_ao_hdr *aoh;
735 struct ip_reply_arg arg;
736#ifdef CONFIG_TCP_MD5SIG
737 struct tcp_md5sig_key *key = NULL;
738 unsigned char newhash[16];
739 struct sock *sk1 = NULL;
740 int genhash;
741#endif
742 u64 transmit_time = 0;
743 struct sock *ctl_sk;
744 struct net *net;
745 u32 txhash = 0;
746
747 /* Never send a reset in response to a reset. */
748 if (th->rst)
749 return;
750
751 /* If sk not NULL, it means we did a successful lookup and incoming
752 * route had to be correct. prequeue might have dropped our dst.
753 */
754 if (!sk && skb_rtable(skb)->rt_type != RTN_LOCAL)
755 return;
756
757 /* Swap the send and the receive. */
758 memset(&rep, 0, sizeof(rep));
759 rep.th.dest = th->source;
760 rep.th.source = th->dest;
761 rep.th.doff = sizeof(struct tcphdr) / 4;
762 rep.th.rst = 1;
763
764 if (th->ack) {
765 rep.th.seq = th->ack_seq;
766 } else {
767 rep.th.ack = 1;
768 rep.th.ack_seq = htonl(ntohl(th->seq) + th->syn + th->fin +
769 skb->len - (th->doff << 2));
770 }
771
772 memset(&arg, 0, sizeof(arg));
773 arg.iov[0].iov_base = (unsigned char *)&rep;
774 arg.iov[0].iov_len = sizeof(rep.th);
775
776 net = sk ? sock_net(sk) : dev_net(skb_dst(skb)->dev);
777
778 /* Invalid TCP option size or twice included auth */
779 if (tcp_parse_auth_options(tcp_hdr(skb), &md5_hash_location, &aoh))
780 return;
781
782 if (aoh && tcp_v4_ao_sign_reset(sk, skb, aoh, &arg, &rep.th, rep.opt))
783 return;
784
785#ifdef CONFIG_TCP_MD5SIG
786 rcu_read_lock();
787 if (sk && sk_fullsock(sk)) {
788 const union tcp_md5_addr *addr;
789 int l3index;
790
791 /* sdif set, means packet ingressed via a device
792 * in an L3 domain and inet_iif is set to it.
793 */
794 l3index = tcp_v4_sdif(skb) ? inet_iif(skb) : 0;
795 addr = (union tcp_md5_addr *)&ip_hdr(skb)->saddr;
796 key = tcp_md5_do_lookup(sk, l3index, addr, AF_INET);
797 } else if (md5_hash_location) {
798 const union tcp_md5_addr *addr;
799 int sdif = tcp_v4_sdif(skb);
800 int dif = inet_iif(skb);
801 int l3index;
802
803 /*
804 * active side is lost. Try to find listening socket through
805 * source port, and then find md5 key through listening socket.
806 * we are not loose security here:
807 * Incoming packet is checked with md5 hash with finding key,
808 * no RST generated if md5 hash doesn't match.
809 */
810 sk1 = __inet_lookup_listener(net, net->ipv4.tcp_death_row.hashinfo,
811 NULL, 0, ip_hdr(skb)->saddr,
812 th->source, ip_hdr(skb)->daddr,
813 ntohs(th->source), dif, sdif);
814 /* don't send rst if it can't find key */
815 if (!sk1)
816 goto out;
817
818 /* sdif set, means packet ingressed via a device
819 * in an L3 domain and dif is set to it.
820 */
821 l3index = sdif ? dif : 0;
822 addr = (union tcp_md5_addr *)&ip_hdr(skb)->saddr;
823 key = tcp_md5_do_lookup(sk1, l3index, addr, AF_INET);
824 if (!key)
825 goto out;
826
827
828 genhash = tcp_v4_md5_hash_skb(newhash, key, NULL, skb);
829 if (genhash || memcmp(md5_hash_location, newhash, 16) != 0)
830 goto out;
831
832 }
833
834 if (key) {
835 rep.opt[0] = htonl((TCPOPT_NOP << 24) |
836 (TCPOPT_NOP << 16) |
837 (TCPOPT_MD5SIG << 8) |
838 TCPOLEN_MD5SIG);
839 /* Update length and the length the header thinks exists */
840 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED;
841 rep.th.doff = arg.iov[0].iov_len / 4;
842
843 tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[1],
844 key, ip_hdr(skb)->saddr,
845 ip_hdr(skb)->daddr, &rep.th);
846 }
847#endif
848 /* Can't co-exist with TCPMD5, hence check rep.opt[0] */
849 if (rep.opt[0] == 0) {
850 __be32 mrst = mptcp_reset_option(skb);
851
852 if (mrst) {
853 rep.opt[0] = mrst;
854 arg.iov[0].iov_len += sizeof(mrst);
855 rep.th.doff = arg.iov[0].iov_len / 4;
856 }
857 }
858
859 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
860 ip_hdr(skb)->saddr, /* XXX */
861 arg.iov[0].iov_len, IPPROTO_TCP, 0);
862 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
863 arg.flags = (sk && inet_sk_transparent(sk)) ? IP_REPLY_ARG_NOSRCCHECK : 0;
864
865 /* When socket is gone, all binding information is lost.
866 * routing might fail in this case. No choice here, if we choose to force
867 * input interface, we will misroute in case of asymmetric route.
868 */
869 if (sk) {
870 arg.bound_dev_if = sk->sk_bound_dev_if;
871 if (sk_fullsock(sk))
872 trace_tcp_send_reset(sk, skb);
873 }
874
875 BUILD_BUG_ON(offsetof(struct sock, sk_bound_dev_if) !=
876 offsetof(struct inet_timewait_sock, tw_bound_dev_if));
877
878 arg.tos = ip_hdr(skb)->tos;
879 arg.uid = sock_net_uid(net, sk && sk_fullsock(sk) ? sk : NULL);
880 local_bh_disable();
881 ctl_sk = this_cpu_read(ipv4_tcp_sk);
882 sock_net_set(ctl_sk, net);
883 if (sk) {
884 ctl_sk->sk_mark = (sk->sk_state == TCP_TIME_WAIT) ?
885 inet_twsk(sk)->tw_mark : sk->sk_mark;
886 ctl_sk->sk_priority = (sk->sk_state == TCP_TIME_WAIT) ?
887 inet_twsk(sk)->tw_priority : READ_ONCE(sk->sk_priority);
888 transmit_time = tcp_transmit_time(sk);
889 xfrm_sk_clone_policy(ctl_sk, sk);
890 txhash = (sk->sk_state == TCP_TIME_WAIT) ?
891 inet_twsk(sk)->tw_txhash : sk->sk_txhash;
892 } else {
893 ctl_sk->sk_mark = 0;
894 ctl_sk->sk_priority = 0;
895 }
896 ip_send_unicast_reply(ctl_sk,
897 skb, &TCP_SKB_CB(skb)->header.h4.opt,
898 ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
899 &arg, arg.iov[0].iov_len,
900 transmit_time, txhash);
901
902 xfrm_sk_free_policy(ctl_sk);
903 sock_net_set(ctl_sk, &init_net);
904 __TCP_INC_STATS(net, TCP_MIB_OUTSEGS);
905 __TCP_INC_STATS(net, TCP_MIB_OUTRSTS);
906 local_bh_enable();
907
908#ifdef CONFIG_TCP_MD5SIG
909out:
910 rcu_read_unlock();
911#endif
912}
913
914/* The code following below sending ACKs in SYN-RECV and TIME-WAIT states
915 outside socket context is ugly, certainly. What can I do?
916 */
917
918static void tcp_v4_send_ack(const struct sock *sk,
919 struct sk_buff *skb, u32 seq, u32 ack,
920 u32 win, u32 tsval, u32 tsecr, int oif,
921 struct tcp_key *key,
922 int reply_flags, u8 tos, u32 txhash)
923{
924 const struct tcphdr *th = tcp_hdr(skb);
925 struct {
926 struct tcphdr th;
927 __be32 opt[(MAX_TCP_OPTION_SPACE >> 2)];
928 } rep;
929 struct net *net = sock_net(sk);
930 struct ip_reply_arg arg;
931 struct sock *ctl_sk;
932 u64 transmit_time;
933
934 memset(&rep.th, 0, sizeof(struct tcphdr));
935 memset(&arg, 0, sizeof(arg));
936
937 arg.iov[0].iov_base = (unsigned char *)&rep;
938 arg.iov[0].iov_len = sizeof(rep.th);
939 if (tsecr) {
940 rep.opt[0] = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
941 (TCPOPT_TIMESTAMP << 8) |
942 TCPOLEN_TIMESTAMP);
943 rep.opt[1] = htonl(tsval);
944 rep.opt[2] = htonl(tsecr);
945 arg.iov[0].iov_len += TCPOLEN_TSTAMP_ALIGNED;
946 }
947
948 /* Swap the send and the receive. */
949 rep.th.dest = th->source;
950 rep.th.source = th->dest;
951 rep.th.doff = arg.iov[0].iov_len / 4;
952 rep.th.seq = htonl(seq);
953 rep.th.ack_seq = htonl(ack);
954 rep.th.ack = 1;
955 rep.th.window = htons(win);
956
957#ifdef CONFIG_TCP_MD5SIG
958 if (tcp_key_is_md5(key)) {
959 int offset = (tsecr) ? 3 : 0;
960
961 rep.opt[offset++] = htonl((TCPOPT_NOP << 24) |
962 (TCPOPT_NOP << 16) |
963 (TCPOPT_MD5SIG << 8) |
964 TCPOLEN_MD5SIG);
965 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED;
966 rep.th.doff = arg.iov[0].iov_len/4;
967
968 tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[offset],
969 key->md5_key, ip_hdr(skb)->saddr,
970 ip_hdr(skb)->daddr, &rep.th);
971 }
972#endif
973#ifdef CONFIG_TCP_AO
974 if (tcp_key_is_ao(key)) {
975 int offset = (tsecr) ? 3 : 0;
976
977 rep.opt[offset++] = htonl((TCPOPT_AO << 24) |
978 (tcp_ao_len(key->ao_key) << 16) |
979 (key->ao_key->sndid << 8) |
980 key->rcv_next);
981 arg.iov[0].iov_len += tcp_ao_len_aligned(key->ao_key);
982 rep.th.doff = arg.iov[0].iov_len / 4;
983
984 tcp_ao_hash_hdr(AF_INET, (char *)&rep.opt[offset],
985 key->ao_key, key->traffic_key,
986 (union tcp_ao_addr *)&ip_hdr(skb)->saddr,
987 (union tcp_ao_addr *)&ip_hdr(skb)->daddr,
988 &rep.th, key->sne);
989 }
990#endif
991 arg.flags = reply_flags;
992 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
993 ip_hdr(skb)->saddr, /* XXX */
994 arg.iov[0].iov_len, IPPROTO_TCP, 0);
995 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
996 if (oif)
997 arg.bound_dev_if = oif;
998 arg.tos = tos;
999 arg.uid = sock_net_uid(net, sk_fullsock(sk) ? sk : NULL);
1000 local_bh_disable();
1001 ctl_sk = this_cpu_read(ipv4_tcp_sk);
1002 sock_net_set(ctl_sk, net);
1003 ctl_sk->sk_mark = (sk->sk_state == TCP_TIME_WAIT) ?
1004 inet_twsk(sk)->tw_mark : READ_ONCE(sk->sk_mark);
1005 ctl_sk->sk_priority = (sk->sk_state == TCP_TIME_WAIT) ?
1006 inet_twsk(sk)->tw_priority : READ_ONCE(sk->sk_priority);
1007 transmit_time = tcp_transmit_time(sk);
1008 ip_send_unicast_reply(ctl_sk,
1009 skb, &TCP_SKB_CB(skb)->header.h4.opt,
1010 ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
1011 &arg, arg.iov[0].iov_len,
1012 transmit_time, txhash);
1013
1014 sock_net_set(ctl_sk, &init_net);
1015 __TCP_INC_STATS(net, TCP_MIB_OUTSEGS);
1016 local_bh_enable();
1017}
1018
1019static void tcp_v4_timewait_ack(struct sock *sk, struct sk_buff *skb)
1020{
1021 struct inet_timewait_sock *tw = inet_twsk(sk);
1022 struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
1023 struct tcp_key key = {};
1024#ifdef CONFIG_TCP_AO
1025 struct tcp_ao_info *ao_info;
1026
1027 if (static_branch_unlikely(&tcp_ao_needed.key)) {
1028 /* FIXME: the segment to-be-acked is not verified yet */
1029 ao_info = rcu_dereference(tcptw->ao_info);
1030 if (ao_info) {
1031 const struct tcp_ao_hdr *aoh;
1032
1033 if (tcp_parse_auth_options(tcp_hdr(skb), NULL, &aoh)) {
1034 inet_twsk_put(tw);
1035 return;
1036 }
1037
1038 if (aoh)
1039 key.ao_key = tcp_ao_established_key(ao_info, aoh->rnext_keyid, -1);
1040 }
1041 }
1042 if (key.ao_key) {
1043 struct tcp_ao_key *rnext_key;
1044
1045 key.traffic_key = snd_other_key(key.ao_key);
1046 key.sne = READ_ONCE(ao_info->snd_sne);
1047 rnext_key = READ_ONCE(ao_info->rnext_key);
1048 key.rcv_next = rnext_key->rcvid;
1049 key.type = TCP_KEY_AO;
1050#else
1051 if (0) {
1052#endif
1053#ifdef CONFIG_TCP_MD5SIG
1054 } else if (static_branch_unlikely(&tcp_md5_needed.key)) {
1055 key.md5_key = tcp_twsk_md5_key(tcptw);
1056 if (key.md5_key)
1057 key.type = TCP_KEY_MD5;
1058#endif
1059 }
1060
1061 tcp_v4_send_ack(sk, skb,
1062 tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
1063 tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
1064 tcp_tw_tsval(tcptw),
1065 tcptw->tw_ts_recent,
1066 tw->tw_bound_dev_if, &key,
1067 tw->tw_transparent ? IP_REPLY_ARG_NOSRCCHECK : 0,
1068 tw->tw_tos,
1069 tw->tw_txhash);
1070
1071 inet_twsk_put(tw);
1072}
1073
1074static void tcp_v4_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb,
1075 struct request_sock *req)
1076{
1077 struct tcp_key key = {};
1078
1079 /* sk->sk_state == TCP_LISTEN -> for regular TCP_SYN_RECV
1080 * sk->sk_state == TCP_SYN_RECV -> for Fast Open.
1081 */
1082 u32 seq = (sk->sk_state == TCP_LISTEN) ? tcp_rsk(req)->snt_isn + 1 :
1083 tcp_sk(sk)->snd_nxt;
1084
1085#ifdef CONFIG_TCP_AO
1086 if (static_branch_unlikely(&tcp_ao_needed.key) &&
1087 tcp_rsk_used_ao(req)) {
1088 const union tcp_md5_addr *addr;
1089 const struct tcp_ao_hdr *aoh;
1090 int l3index;
1091
1092 /* Invalid TCP option size or twice included auth */
1093 if (tcp_parse_auth_options(tcp_hdr(skb), NULL, &aoh))
1094 return;
1095 if (!aoh)
1096 return;
1097
1098 addr = (union tcp_md5_addr *)&ip_hdr(skb)->saddr;
1099 l3index = tcp_v4_sdif(skb) ? inet_iif(skb) : 0;
1100 key.ao_key = tcp_ao_do_lookup(sk, l3index, addr, AF_INET,
1101 aoh->rnext_keyid, -1);
1102 if (unlikely(!key.ao_key)) {
1103 /* Send ACK with any matching MKT for the peer */
1104 key.ao_key = tcp_ao_do_lookup(sk, l3index, addr, AF_INET, -1, -1);
1105 /* Matching key disappeared (user removed the key?)
1106 * let the handshake timeout.
1107 */
1108 if (!key.ao_key) {
1109 net_info_ratelimited("TCP-AO key for (%pI4, %d)->(%pI4, %d) suddenly disappeared, won't ACK new connection\n",
1110 addr,
1111 ntohs(tcp_hdr(skb)->source),
1112 &ip_hdr(skb)->daddr,
1113 ntohs(tcp_hdr(skb)->dest));
1114 return;
1115 }
1116 }
1117 key.traffic_key = kmalloc(tcp_ao_digest_size(key.ao_key), GFP_ATOMIC);
1118 if (!key.traffic_key)
1119 return;
1120
1121 key.type = TCP_KEY_AO;
1122 key.rcv_next = aoh->keyid;
1123 tcp_v4_ao_calc_key_rsk(key.ao_key, key.traffic_key, req);
1124#else
1125 if (0) {
1126#endif
1127#ifdef CONFIG_TCP_MD5SIG
1128 } else if (static_branch_unlikely(&tcp_md5_needed.key)) {
1129 const union tcp_md5_addr *addr;
1130 int l3index;
1131
1132 addr = (union tcp_md5_addr *)&ip_hdr(skb)->saddr;
1133 l3index = tcp_v4_sdif(skb) ? inet_iif(skb) : 0;
1134 key.md5_key = tcp_md5_do_lookup(sk, l3index, addr, AF_INET);
1135 if (key.md5_key)
1136 key.type = TCP_KEY_MD5;
1137#endif
1138 }
1139
1140 /* RFC 7323 2.3
1141 * The window field (SEG.WND) of every outgoing segment, with the
1142 * exception of <SYN> segments, MUST be right-shifted by
1143 * Rcv.Wind.Shift bits:
1144 */
1145 tcp_v4_send_ack(sk, skb, seq,
1146 tcp_rsk(req)->rcv_nxt,
1147 req->rsk_rcv_wnd >> inet_rsk(req)->rcv_wscale,
1148 tcp_rsk_tsval(tcp_rsk(req)),
1149 READ_ONCE(req->ts_recent),
1150 0, &key,
1151 inet_rsk(req)->no_srccheck ? IP_REPLY_ARG_NOSRCCHECK : 0,
1152 ip_hdr(skb)->tos,
1153 READ_ONCE(tcp_rsk(req)->txhash));
1154 if (tcp_key_is_ao(&key))
1155 kfree(key.traffic_key);
1156}
1157
1158/*
1159 * Send a SYN-ACK after having received a SYN.
1160 * This still operates on a request_sock only, not on a big
1161 * socket.
1162 */
1163static int tcp_v4_send_synack(const struct sock *sk, struct dst_entry *dst,
1164 struct flowi *fl,
1165 struct request_sock *req,
1166 struct tcp_fastopen_cookie *foc,
1167 enum tcp_synack_type synack_type,
1168 struct sk_buff *syn_skb)
1169{
1170 const struct inet_request_sock *ireq = inet_rsk(req);
1171 struct flowi4 fl4;
1172 int err = -1;
1173 struct sk_buff *skb;
1174 u8 tos;
1175
1176 /* First, grab a route. */
1177 if (!dst && (dst = inet_csk_route_req(sk, &fl4, req)) == NULL)
1178 return -1;
1179
1180 skb = tcp_make_synack(sk, dst, req, foc, synack_type, syn_skb);
1181
1182 if (skb) {
1183 __tcp_v4_send_check(skb, ireq->ir_loc_addr, ireq->ir_rmt_addr);
1184
1185 tos = READ_ONCE(inet_sk(sk)->tos);
1186
1187 if (READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_reflect_tos))
1188 tos = (tcp_rsk(req)->syn_tos & ~INET_ECN_MASK) |
1189 (tos & INET_ECN_MASK);
1190
1191 if (!INET_ECN_is_capable(tos) &&
1192 tcp_bpf_ca_needs_ecn((struct sock *)req))
1193 tos |= INET_ECN_ECT_0;
1194
1195 rcu_read_lock();
1196 err = ip_build_and_send_pkt(skb, sk, ireq->ir_loc_addr,
1197 ireq->ir_rmt_addr,
1198 rcu_dereference(ireq->ireq_opt),
1199 tos);
1200 rcu_read_unlock();
1201 err = net_xmit_eval(err);
1202 }
1203
1204 return err;
1205}
1206
1207/*
1208 * IPv4 request_sock destructor.
1209 */
1210static void tcp_v4_reqsk_destructor(struct request_sock *req)
1211{
1212 kfree(rcu_dereference_protected(inet_rsk(req)->ireq_opt, 1));
1213}
1214
1215#ifdef CONFIG_TCP_MD5SIG
1216/*
1217 * RFC2385 MD5 checksumming requires a mapping of
1218 * IP address->MD5 Key.
1219 * We need to maintain these in the sk structure.
1220 */
1221
1222DEFINE_STATIC_KEY_DEFERRED_FALSE(tcp_md5_needed, HZ);
1223EXPORT_SYMBOL(tcp_md5_needed);
1224
1225static bool better_md5_match(struct tcp_md5sig_key *old, struct tcp_md5sig_key *new)
1226{
1227 if (!old)
1228 return true;
1229
1230 /* l3index always overrides non-l3index */
1231 if (old->l3index && new->l3index == 0)
1232 return false;
1233 if (old->l3index == 0 && new->l3index)
1234 return true;
1235
1236 return old->prefixlen < new->prefixlen;
1237}
1238
1239/* Find the Key structure for an address. */
1240struct tcp_md5sig_key *__tcp_md5_do_lookup(const struct sock *sk, int l3index,
1241 const union tcp_md5_addr *addr,
1242 int family, bool any_l3index)
1243{
1244 const struct tcp_sock *tp = tcp_sk(sk);
1245 struct tcp_md5sig_key *key;
1246 const struct tcp_md5sig_info *md5sig;
1247 __be32 mask;
1248 struct tcp_md5sig_key *best_match = NULL;
1249 bool match;
1250
1251 /* caller either holds rcu_read_lock() or socket lock */
1252 md5sig = rcu_dereference_check(tp->md5sig_info,
1253 lockdep_sock_is_held(sk));
1254 if (!md5sig)
1255 return NULL;
1256
1257 hlist_for_each_entry_rcu(key, &md5sig->head, node,
1258 lockdep_sock_is_held(sk)) {
1259 if (key->family != family)
1260 continue;
1261 if (!any_l3index && key->flags & TCP_MD5SIG_FLAG_IFINDEX &&
1262 key->l3index != l3index)
1263 continue;
1264 if (family == AF_INET) {
1265 mask = inet_make_mask(key->prefixlen);
1266 match = (key->addr.a4.s_addr & mask) ==
1267 (addr->a4.s_addr & mask);
1268#if IS_ENABLED(CONFIG_IPV6)
1269 } else if (family == AF_INET6) {
1270 match = ipv6_prefix_equal(&key->addr.a6, &addr->a6,
1271 key->prefixlen);
1272#endif
1273 } else {
1274 match = false;
1275 }
1276
1277 if (match && better_md5_match(best_match, key))
1278 best_match = key;
1279 }
1280 return best_match;
1281}
1282EXPORT_SYMBOL(__tcp_md5_do_lookup);
1283
1284static struct tcp_md5sig_key *tcp_md5_do_lookup_exact(const struct sock *sk,
1285 const union tcp_md5_addr *addr,
1286 int family, u8 prefixlen,
1287 int l3index, u8 flags)
1288{
1289 const struct tcp_sock *tp = tcp_sk(sk);
1290 struct tcp_md5sig_key *key;
1291 unsigned int size = sizeof(struct in_addr);
1292 const struct tcp_md5sig_info *md5sig;
1293
1294 /* caller either holds rcu_read_lock() or socket lock */
1295 md5sig = rcu_dereference_check(tp->md5sig_info,
1296 lockdep_sock_is_held(sk));
1297 if (!md5sig)
1298 return NULL;
1299#if IS_ENABLED(CONFIG_IPV6)
1300 if (family == AF_INET6)
1301 size = sizeof(struct in6_addr);
1302#endif
1303 hlist_for_each_entry_rcu(key, &md5sig->head, node,
1304 lockdep_sock_is_held(sk)) {
1305 if (key->family != family)
1306 continue;
1307 if ((key->flags & TCP_MD5SIG_FLAG_IFINDEX) != (flags & TCP_MD5SIG_FLAG_IFINDEX))
1308 continue;
1309 if (key->l3index != l3index)
1310 continue;
1311 if (!memcmp(&key->addr, addr, size) &&
1312 key->prefixlen == prefixlen)
1313 return key;
1314 }
1315 return NULL;
1316}
1317
1318struct tcp_md5sig_key *tcp_v4_md5_lookup(const struct sock *sk,
1319 const struct sock *addr_sk)
1320{
1321 const union tcp_md5_addr *addr;
1322 int l3index;
1323
1324 l3index = l3mdev_master_ifindex_by_index(sock_net(sk),
1325 addr_sk->sk_bound_dev_if);
1326 addr = (const union tcp_md5_addr *)&addr_sk->sk_daddr;
1327 return tcp_md5_do_lookup(sk, l3index, addr, AF_INET);
1328}
1329EXPORT_SYMBOL(tcp_v4_md5_lookup);
1330
1331static int tcp_md5sig_info_add(struct sock *sk, gfp_t gfp)
1332{
1333 struct tcp_sock *tp = tcp_sk(sk);
1334 struct tcp_md5sig_info *md5sig;
1335
1336 md5sig = kmalloc(sizeof(*md5sig), gfp);
1337 if (!md5sig)
1338 return -ENOMEM;
1339
1340 sk_gso_disable(sk);
1341 INIT_HLIST_HEAD(&md5sig->head);
1342 rcu_assign_pointer(tp->md5sig_info, md5sig);
1343 return 0;
1344}
1345
1346/* This can be called on a newly created socket, from other files */
1347static int __tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr,
1348 int family, u8 prefixlen, int l3index, u8 flags,
1349 const u8 *newkey, u8 newkeylen, gfp_t gfp)
1350{
1351 /* Add Key to the list */
1352 struct tcp_md5sig_key *key;
1353 struct tcp_sock *tp = tcp_sk(sk);
1354 struct tcp_md5sig_info *md5sig;
1355
1356 key = tcp_md5_do_lookup_exact(sk, addr, family, prefixlen, l3index, flags);
1357 if (key) {
1358 /* Pre-existing entry - just update that one.
1359 * Note that the key might be used concurrently.
1360 * data_race() is telling kcsan that we do not care of
1361 * key mismatches, since changing MD5 key on live flows
1362 * can lead to packet drops.
1363 */
1364 data_race(memcpy(key->key, newkey, newkeylen));
1365
1366 /* Pairs with READ_ONCE() in tcp_md5_hash_key().
1367 * Also note that a reader could catch new key->keylen value
1368 * but old key->key[], this is the reason we use __GFP_ZERO
1369 * at sock_kmalloc() time below these lines.
1370 */
1371 WRITE_ONCE(key->keylen, newkeylen);
1372
1373 return 0;
1374 }
1375
1376 md5sig = rcu_dereference_protected(tp->md5sig_info,
1377 lockdep_sock_is_held(sk));
1378
1379 key = sock_kmalloc(sk, sizeof(*key), gfp | __GFP_ZERO);
1380 if (!key)
1381 return -ENOMEM;
1382
1383 memcpy(key->key, newkey, newkeylen);
1384 key->keylen = newkeylen;
1385 key->family = family;
1386 key->prefixlen = prefixlen;
1387 key->l3index = l3index;
1388 key->flags = flags;
1389 memcpy(&key->addr, addr,
1390 (IS_ENABLED(CONFIG_IPV6) && family == AF_INET6) ? sizeof(struct in6_addr) :
1391 sizeof(struct in_addr));
1392 hlist_add_head_rcu(&key->node, &md5sig->head);
1393 return 0;
1394}
1395
1396int tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr,
1397 int family, u8 prefixlen, int l3index, u8 flags,
1398 const u8 *newkey, u8 newkeylen)
1399{
1400 struct tcp_sock *tp = tcp_sk(sk);
1401
1402 if (!rcu_dereference_protected(tp->md5sig_info, lockdep_sock_is_held(sk))) {
1403 if (tcp_md5_alloc_sigpool())
1404 return -ENOMEM;
1405
1406 if (tcp_md5sig_info_add(sk, GFP_KERNEL)) {
1407 tcp_md5_release_sigpool();
1408 return -ENOMEM;
1409 }
1410
1411 if (!static_branch_inc(&tcp_md5_needed.key)) {
1412 struct tcp_md5sig_info *md5sig;
1413
1414 md5sig = rcu_dereference_protected(tp->md5sig_info, lockdep_sock_is_held(sk));
1415 rcu_assign_pointer(tp->md5sig_info, NULL);
1416 kfree_rcu(md5sig, rcu);
1417 tcp_md5_release_sigpool();
1418 return -EUSERS;
1419 }
1420 }
1421
1422 return __tcp_md5_do_add(sk, addr, family, prefixlen, l3index, flags,
1423 newkey, newkeylen, GFP_KERNEL);
1424}
1425EXPORT_SYMBOL(tcp_md5_do_add);
1426
1427int tcp_md5_key_copy(struct sock *sk, const union tcp_md5_addr *addr,
1428 int family, u8 prefixlen, int l3index,
1429 struct tcp_md5sig_key *key)
1430{
1431 struct tcp_sock *tp = tcp_sk(sk);
1432
1433 if (!rcu_dereference_protected(tp->md5sig_info, lockdep_sock_is_held(sk))) {
1434 tcp_md5_add_sigpool();
1435
1436 if (tcp_md5sig_info_add(sk, sk_gfp_mask(sk, GFP_ATOMIC))) {
1437 tcp_md5_release_sigpool();
1438 return -ENOMEM;
1439 }
1440
1441 if (!static_key_fast_inc_not_disabled(&tcp_md5_needed.key.key)) {
1442 struct tcp_md5sig_info *md5sig;
1443
1444 md5sig = rcu_dereference_protected(tp->md5sig_info, lockdep_sock_is_held(sk));
1445 net_warn_ratelimited("Too many TCP-MD5 keys in the system\n");
1446 rcu_assign_pointer(tp->md5sig_info, NULL);
1447 kfree_rcu(md5sig, rcu);
1448 tcp_md5_release_sigpool();
1449 return -EUSERS;
1450 }
1451 }
1452
1453 return __tcp_md5_do_add(sk, addr, family, prefixlen, l3index,
1454 key->flags, key->key, key->keylen,
1455 sk_gfp_mask(sk, GFP_ATOMIC));
1456}
1457EXPORT_SYMBOL(tcp_md5_key_copy);
1458
1459int tcp_md5_do_del(struct sock *sk, const union tcp_md5_addr *addr, int family,
1460 u8 prefixlen, int l3index, u8 flags)
1461{
1462 struct tcp_md5sig_key *key;
1463
1464 key = tcp_md5_do_lookup_exact(sk, addr, family, prefixlen, l3index, flags);
1465 if (!key)
1466 return -ENOENT;
1467 hlist_del_rcu(&key->node);
1468 atomic_sub(sizeof(*key), &sk->sk_omem_alloc);
1469 kfree_rcu(key, rcu);
1470 return 0;
1471}
1472EXPORT_SYMBOL(tcp_md5_do_del);
1473
1474void tcp_clear_md5_list(struct sock *sk)
1475{
1476 struct tcp_sock *tp = tcp_sk(sk);
1477 struct tcp_md5sig_key *key;
1478 struct hlist_node *n;
1479 struct tcp_md5sig_info *md5sig;
1480
1481 md5sig = rcu_dereference_protected(tp->md5sig_info, 1);
1482
1483 hlist_for_each_entry_safe(key, n, &md5sig->head, node) {
1484 hlist_del_rcu(&key->node);
1485 atomic_sub(sizeof(*key), &sk->sk_omem_alloc);
1486 kfree_rcu(key, rcu);
1487 }
1488}
1489
1490static int tcp_v4_parse_md5_keys(struct sock *sk, int optname,
1491 sockptr_t optval, int optlen)
1492{
1493 struct tcp_md5sig cmd;
1494 struct sockaddr_in *sin = (struct sockaddr_in *)&cmd.tcpm_addr;
1495 const union tcp_md5_addr *addr;
1496 u8 prefixlen = 32;
1497 int l3index = 0;
1498 bool l3flag;
1499 u8 flags;
1500
1501 if (optlen < sizeof(cmd))
1502 return -EINVAL;
1503
1504 if (copy_from_sockptr(&cmd, optval, sizeof(cmd)))
1505 return -EFAULT;
1506
1507 if (sin->sin_family != AF_INET)
1508 return -EINVAL;
1509
1510 flags = cmd.tcpm_flags & TCP_MD5SIG_FLAG_IFINDEX;
1511 l3flag = cmd.tcpm_flags & TCP_MD5SIG_FLAG_IFINDEX;
1512
1513 if (optname == TCP_MD5SIG_EXT &&
1514 cmd.tcpm_flags & TCP_MD5SIG_FLAG_PREFIX) {
1515 prefixlen = cmd.tcpm_prefixlen;
1516 if (prefixlen > 32)
1517 return -EINVAL;
1518 }
1519
1520 if (optname == TCP_MD5SIG_EXT && cmd.tcpm_ifindex &&
1521 cmd.tcpm_flags & TCP_MD5SIG_FLAG_IFINDEX) {
1522 struct net_device *dev;
1523
1524 rcu_read_lock();
1525 dev = dev_get_by_index_rcu(sock_net(sk), cmd.tcpm_ifindex);
1526 if (dev && netif_is_l3_master(dev))
1527 l3index = dev->ifindex;
1528
1529 rcu_read_unlock();
1530
1531 /* ok to reference set/not set outside of rcu;
1532 * right now device MUST be an L3 master
1533 */
1534 if (!dev || !l3index)
1535 return -EINVAL;
1536 }
1537
1538 addr = (union tcp_md5_addr *)&sin->sin_addr.s_addr;
1539
1540 if (!cmd.tcpm_keylen)
1541 return tcp_md5_do_del(sk, addr, AF_INET, prefixlen, l3index, flags);
1542
1543 if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN)
1544 return -EINVAL;
1545
1546 /* Don't allow keys for peers that have a matching TCP-AO key.
1547 * See the comment in tcp_ao_add_cmd()
1548 */
1549 if (tcp_ao_required(sk, addr, AF_INET, l3flag ? l3index : -1, false))
1550 return -EKEYREJECTED;
1551
1552 return tcp_md5_do_add(sk, addr, AF_INET, prefixlen, l3index, flags,
1553 cmd.tcpm_key, cmd.tcpm_keylen);
1554}
1555
1556static int tcp_v4_md5_hash_headers(struct tcp_sigpool *hp,
1557 __be32 daddr, __be32 saddr,
1558 const struct tcphdr *th, int nbytes)
1559{
1560 struct tcp4_pseudohdr *bp;
1561 struct scatterlist sg;
1562 struct tcphdr *_th;
1563
1564 bp = hp->scratch;
1565 bp->saddr = saddr;
1566 bp->daddr = daddr;
1567 bp->pad = 0;
1568 bp->protocol = IPPROTO_TCP;
1569 bp->len = cpu_to_be16(nbytes);
1570
1571 _th = (struct tcphdr *)(bp + 1);
1572 memcpy(_th, th, sizeof(*th));
1573 _th->check = 0;
1574
1575 sg_init_one(&sg, bp, sizeof(*bp) + sizeof(*th));
1576 ahash_request_set_crypt(hp->req, &sg, NULL,
1577 sizeof(*bp) + sizeof(*th));
1578 return crypto_ahash_update(hp->req);
1579}
1580
1581static int tcp_v4_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key,
1582 __be32 daddr, __be32 saddr, const struct tcphdr *th)
1583{
1584 struct tcp_sigpool hp;
1585
1586 if (tcp_sigpool_start(tcp_md5_sigpool_id, &hp))
1587 goto clear_hash_nostart;
1588
1589 if (crypto_ahash_init(hp.req))
1590 goto clear_hash;
1591 if (tcp_v4_md5_hash_headers(&hp, daddr, saddr, th, th->doff << 2))
1592 goto clear_hash;
1593 if (tcp_md5_hash_key(&hp, key))
1594 goto clear_hash;
1595 ahash_request_set_crypt(hp.req, NULL, md5_hash, 0);
1596 if (crypto_ahash_final(hp.req))
1597 goto clear_hash;
1598
1599 tcp_sigpool_end(&hp);
1600 return 0;
1601
1602clear_hash:
1603 tcp_sigpool_end(&hp);
1604clear_hash_nostart:
1605 memset(md5_hash, 0, 16);
1606 return 1;
1607}
1608
1609int tcp_v4_md5_hash_skb(char *md5_hash, const struct tcp_md5sig_key *key,
1610 const struct sock *sk,
1611 const struct sk_buff *skb)
1612{
1613 const struct tcphdr *th = tcp_hdr(skb);
1614 struct tcp_sigpool hp;
1615 __be32 saddr, daddr;
1616
1617 if (sk) { /* valid for establish/request sockets */
1618 saddr = sk->sk_rcv_saddr;
1619 daddr = sk->sk_daddr;
1620 } else {
1621 const struct iphdr *iph = ip_hdr(skb);
1622 saddr = iph->saddr;
1623 daddr = iph->daddr;
1624 }
1625
1626 if (tcp_sigpool_start(tcp_md5_sigpool_id, &hp))
1627 goto clear_hash_nostart;
1628
1629 if (crypto_ahash_init(hp.req))
1630 goto clear_hash;
1631
1632 if (tcp_v4_md5_hash_headers(&hp, daddr, saddr, th, skb->len))
1633 goto clear_hash;
1634 if (tcp_sigpool_hash_skb_data(&hp, skb, th->doff << 2))
1635 goto clear_hash;
1636 if (tcp_md5_hash_key(&hp, key))
1637 goto clear_hash;
1638 ahash_request_set_crypt(hp.req, NULL, md5_hash, 0);
1639 if (crypto_ahash_final(hp.req))
1640 goto clear_hash;
1641
1642 tcp_sigpool_end(&hp);
1643 return 0;
1644
1645clear_hash:
1646 tcp_sigpool_end(&hp);
1647clear_hash_nostart:
1648 memset(md5_hash, 0, 16);
1649 return 1;
1650}
1651EXPORT_SYMBOL(tcp_v4_md5_hash_skb);
1652
1653#endif
1654
1655static void tcp_v4_init_req(struct request_sock *req,
1656 const struct sock *sk_listener,
1657 struct sk_buff *skb)
1658{
1659 struct inet_request_sock *ireq = inet_rsk(req);
1660 struct net *net = sock_net(sk_listener);
1661
1662 sk_rcv_saddr_set(req_to_sk(req), ip_hdr(skb)->daddr);
1663 sk_daddr_set(req_to_sk(req), ip_hdr(skb)->saddr);
1664 RCU_INIT_POINTER(ireq->ireq_opt, tcp_v4_save_options(net, skb));
1665}
1666
1667static struct dst_entry *tcp_v4_route_req(const struct sock *sk,
1668 struct sk_buff *skb,
1669 struct flowi *fl,
1670 struct request_sock *req)
1671{
1672 tcp_v4_init_req(req, sk, skb);
1673
1674 if (security_inet_conn_request(sk, skb, req))
1675 return NULL;
1676
1677 return inet_csk_route_req(sk, &fl->u.ip4, req);
1678}
1679
1680struct request_sock_ops tcp_request_sock_ops __read_mostly = {
1681 .family = PF_INET,
1682 .obj_size = sizeof(struct tcp_request_sock),
1683 .rtx_syn_ack = tcp_rtx_synack,
1684 .send_ack = tcp_v4_reqsk_send_ack,
1685 .destructor = tcp_v4_reqsk_destructor,
1686 .send_reset = tcp_v4_send_reset,
1687 .syn_ack_timeout = tcp_syn_ack_timeout,
1688};
1689
1690const struct tcp_request_sock_ops tcp_request_sock_ipv4_ops = {
1691 .mss_clamp = TCP_MSS_DEFAULT,
1692#ifdef CONFIG_TCP_MD5SIG
1693 .req_md5_lookup = tcp_v4_md5_lookup,
1694 .calc_md5_hash = tcp_v4_md5_hash_skb,
1695#endif
1696#ifdef CONFIG_TCP_AO
1697 .ao_lookup = tcp_v4_ao_lookup_rsk,
1698 .ao_calc_key = tcp_v4_ao_calc_key_rsk,
1699 .ao_synack_hash = tcp_v4_ao_synack_hash,
1700#endif
1701#ifdef CONFIG_SYN_COOKIES
1702 .cookie_init_seq = cookie_v4_init_sequence,
1703#endif
1704 .route_req = tcp_v4_route_req,
1705 .init_seq = tcp_v4_init_seq,
1706 .init_ts_off = tcp_v4_init_ts_off,
1707 .send_synack = tcp_v4_send_synack,
1708};
1709
1710int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
1711{
1712 /* Never answer to SYNs send to broadcast or multicast */
1713 if (skb_rtable(skb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
1714 goto drop;
1715
1716 return tcp_conn_request(&tcp_request_sock_ops,
1717 &tcp_request_sock_ipv4_ops, sk, skb);
1718
1719drop:
1720 tcp_listendrop(sk);
1721 return 0;
1722}
1723EXPORT_SYMBOL(tcp_v4_conn_request);
1724
1725
1726/*
1727 * The three way handshake has completed - we got a valid synack -
1728 * now create the new socket.
1729 */
1730struct sock *tcp_v4_syn_recv_sock(const struct sock *sk, struct sk_buff *skb,
1731 struct request_sock *req,
1732 struct dst_entry *dst,
1733 struct request_sock *req_unhash,
1734 bool *own_req)
1735{
1736 struct inet_request_sock *ireq;
1737 bool found_dup_sk = false;
1738 struct inet_sock *newinet;
1739 struct tcp_sock *newtp;
1740 struct sock *newsk;
1741#ifdef CONFIG_TCP_MD5SIG
1742 const union tcp_md5_addr *addr;
1743 struct tcp_md5sig_key *key;
1744 int l3index;
1745#endif
1746 struct ip_options_rcu *inet_opt;
1747
1748 if (sk_acceptq_is_full(sk))
1749 goto exit_overflow;
1750
1751 newsk = tcp_create_openreq_child(sk, req, skb);
1752 if (!newsk)
1753 goto exit_nonewsk;
1754
1755 newsk->sk_gso_type = SKB_GSO_TCPV4;
1756 inet_sk_rx_dst_set(newsk, skb);
1757
1758 newtp = tcp_sk(newsk);
1759 newinet = inet_sk(newsk);
1760 ireq = inet_rsk(req);
1761 sk_daddr_set(newsk, ireq->ir_rmt_addr);
1762 sk_rcv_saddr_set(newsk, ireq->ir_loc_addr);
1763 newsk->sk_bound_dev_if = ireq->ir_iif;
1764 newinet->inet_saddr = ireq->ir_loc_addr;
1765 inet_opt = rcu_dereference(ireq->ireq_opt);
1766 RCU_INIT_POINTER(newinet->inet_opt, inet_opt);
1767 newinet->mc_index = inet_iif(skb);
1768 newinet->mc_ttl = ip_hdr(skb)->ttl;
1769 newinet->rcv_tos = ip_hdr(skb)->tos;
1770 inet_csk(newsk)->icsk_ext_hdr_len = 0;
1771 if (inet_opt)
1772 inet_csk(newsk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
1773 atomic_set(&newinet->inet_id, get_random_u16());
1774
1775 /* Set ToS of the new socket based upon the value of incoming SYN.
1776 * ECT bits are set later in tcp_init_transfer().
1777 */
1778 if (READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_reflect_tos))
1779 newinet->tos = tcp_rsk(req)->syn_tos & ~INET_ECN_MASK;
1780
1781 if (!dst) {
1782 dst = inet_csk_route_child_sock(sk, newsk, req);
1783 if (!dst)
1784 goto put_and_exit;
1785 } else {
1786 /* syncookie case : see end of cookie_v4_check() */
1787 }
1788 sk_setup_caps(newsk, dst);
1789
1790 tcp_ca_openreq_child(newsk, dst);
1791
1792 tcp_sync_mss(newsk, dst_mtu(dst));
1793 newtp->advmss = tcp_mss_clamp(tcp_sk(sk), dst_metric_advmss(dst));
1794
1795 tcp_initialize_rcv_mss(newsk);
1796
1797#ifdef CONFIG_TCP_MD5SIG
1798 l3index = l3mdev_master_ifindex_by_index(sock_net(sk), ireq->ir_iif);
1799 /* Copy over the MD5 key from the original socket */
1800 addr = (union tcp_md5_addr *)&newinet->inet_daddr;
1801 key = tcp_md5_do_lookup(sk, l3index, addr, AF_INET);
1802 if (key && !tcp_rsk_used_ao(req)) {
1803 if (tcp_md5_key_copy(newsk, addr, AF_INET, 32, l3index, key))
1804 goto put_and_exit;
1805 sk_gso_disable(newsk);
1806 }
1807#endif
1808#ifdef CONFIG_TCP_AO
1809 if (tcp_ao_copy_all_matching(sk, newsk, req, skb, AF_INET))
1810 goto put_and_exit; /* OOM, release back memory */
1811#endif
1812
1813 if (__inet_inherit_port(sk, newsk) < 0)
1814 goto put_and_exit;
1815 *own_req = inet_ehash_nolisten(newsk, req_to_sk(req_unhash),
1816 &found_dup_sk);
1817 if (likely(*own_req)) {
1818 tcp_move_syn(newtp, req);
1819 ireq->ireq_opt = NULL;
1820 } else {
1821 newinet->inet_opt = NULL;
1822
1823 if (!req_unhash && found_dup_sk) {
1824 /* This code path should only be executed in the
1825 * syncookie case only
1826 */
1827 bh_unlock_sock(newsk);
1828 sock_put(newsk);
1829 newsk = NULL;
1830 }
1831 }
1832 return newsk;
1833
1834exit_overflow:
1835 NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
1836exit_nonewsk:
1837 dst_release(dst);
1838exit:
1839 tcp_listendrop(sk);
1840 return NULL;
1841put_and_exit:
1842 newinet->inet_opt = NULL;
1843 inet_csk_prepare_forced_close(newsk);
1844 tcp_done(newsk);
1845 goto exit;
1846}
1847EXPORT_SYMBOL(tcp_v4_syn_recv_sock);
1848
1849static struct sock *tcp_v4_cookie_check(struct sock *sk, struct sk_buff *skb)
1850{
1851#ifdef CONFIG_SYN_COOKIES
1852 const struct tcphdr *th = tcp_hdr(skb);
1853
1854 if (!th->syn)
1855 sk = cookie_v4_check(sk, skb);
1856#endif
1857 return sk;
1858}
1859
1860u16 tcp_v4_get_syncookie(struct sock *sk, struct iphdr *iph,
1861 struct tcphdr *th, u32 *cookie)
1862{
1863 u16 mss = 0;
1864#ifdef CONFIG_SYN_COOKIES
1865 mss = tcp_get_syncookie_mss(&tcp_request_sock_ops,
1866 &tcp_request_sock_ipv4_ops, sk, th);
1867 if (mss) {
1868 *cookie = __cookie_v4_init_sequence(iph, th, &mss);
1869 tcp_synq_overflow(sk);
1870 }
1871#endif
1872 return mss;
1873}
1874
1875INDIRECT_CALLABLE_DECLARE(struct dst_entry *ipv4_dst_check(struct dst_entry *,
1876 u32));
1877/* The socket must have it's spinlock held when we get
1878 * here, unless it is a TCP_LISTEN socket.
1879 *
1880 * We have a potential double-lock case here, so even when
1881 * doing backlog processing we use the BH locking scheme.
1882 * This is because we cannot sleep with the original spinlock
1883 * held.
1884 */
1885int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
1886{
1887 enum skb_drop_reason reason;
1888 struct sock *rsk;
1889
1890 if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
1891 struct dst_entry *dst;
1892
1893 dst = rcu_dereference_protected(sk->sk_rx_dst,
1894 lockdep_sock_is_held(sk));
1895
1896 sock_rps_save_rxhash(sk, skb);
1897 sk_mark_napi_id(sk, skb);
1898 if (dst) {
1899 if (sk->sk_rx_dst_ifindex != skb->skb_iif ||
1900 !INDIRECT_CALL_1(dst->ops->check, ipv4_dst_check,
1901 dst, 0)) {
1902 RCU_INIT_POINTER(sk->sk_rx_dst, NULL);
1903 dst_release(dst);
1904 }
1905 }
1906 tcp_rcv_established(sk, skb);
1907 return 0;
1908 }
1909
1910 reason = SKB_DROP_REASON_NOT_SPECIFIED;
1911 if (tcp_checksum_complete(skb))
1912 goto csum_err;
1913
1914 if (sk->sk_state == TCP_LISTEN) {
1915 struct sock *nsk = tcp_v4_cookie_check(sk, skb);
1916
1917 if (!nsk)
1918 goto discard;
1919 if (nsk != sk) {
1920 if (tcp_child_process(sk, nsk, skb)) {
1921 rsk = nsk;
1922 goto reset;
1923 }
1924 return 0;
1925 }
1926 } else
1927 sock_rps_save_rxhash(sk, skb);
1928
1929 if (tcp_rcv_state_process(sk, skb)) {
1930 rsk = sk;
1931 goto reset;
1932 }
1933 return 0;
1934
1935reset:
1936 tcp_v4_send_reset(rsk, skb);
1937discard:
1938 kfree_skb_reason(skb, reason);
1939 /* Be careful here. If this function gets more complicated and
1940 * gcc suffers from register pressure on the x86, sk (in %ebx)
1941 * might be destroyed here. This current version compiles correctly,
1942 * but you have been warned.
1943 */
1944 return 0;
1945
1946csum_err:
1947 reason = SKB_DROP_REASON_TCP_CSUM;
1948 trace_tcp_bad_csum(skb);
1949 TCP_INC_STATS(sock_net(sk), TCP_MIB_CSUMERRORS);
1950 TCP_INC_STATS(sock_net(sk), TCP_MIB_INERRS);
1951 goto discard;
1952}
1953EXPORT_SYMBOL(tcp_v4_do_rcv);
1954
1955int tcp_v4_early_demux(struct sk_buff *skb)
1956{
1957 struct net *net = dev_net(skb->dev);
1958 const struct iphdr *iph;
1959 const struct tcphdr *th;
1960 struct sock *sk;
1961
1962 if (skb->pkt_type != PACKET_HOST)
1963 return 0;
1964
1965 if (!pskb_may_pull(skb, skb_transport_offset(skb) + sizeof(struct tcphdr)))
1966 return 0;
1967
1968 iph = ip_hdr(skb);
1969 th = tcp_hdr(skb);
1970
1971 if (th->doff < sizeof(struct tcphdr) / 4)
1972 return 0;
1973
1974 sk = __inet_lookup_established(net, net->ipv4.tcp_death_row.hashinfo,
1975 iph->saddr, th->source,
1976 iph->daddr, ntohs(th->dest),
1977 skb->skb_iif, inet_sdif(skb));
1978 if (sk) {
1979 skb->sk = sk;
1980 skb->destructor = sock_edemux;
1981 if (sk_fullsock(sk)) {
1982 struct dst_entry *dst = rcu_dereference(sk->sk_rx_dst);
1983
1984 if (dst)
1985 dst = dst_check(dst, 0);
1986 if (dst &&
1987 sk->sk_rx_dst_ifindex == skb->skb_iif)
1988 skb_dst_set_noref(skb, dst);
1989 }
1990 }
1991 return 0;
1992}
1993
1994bool tcp_add_backlog(struct sock *sk, struct sk_buff *skb,
1995 enum skb_drop_reason *reason)
1996{
1997 u32 limit, tail_gso_size, tail_gso_segs;
1998 struct skb_shared_info *shinfo;
1999 const struct tcphdr *th;
2000 struct tcphdr *thtail;
2001 struct sk_buff *tail;
2002 unsigned int hdrlen;
2003 bool fragstolen;
2004 u32 gso_segs;
2005 u32 gso_size;
2006 int delta;
2007
2008 /* In case all data was pulled from skb frags (in __pskb_pull_tail()),
2009 * we can fix skb->truesize to its real value to avoid future drops.
2010 * This is valid because skb is not yet charged to the socket.
2011 * It has been noticed pure SACK packets were sometimes dropped
2012 * (if cooked by drivers without copybreak feature).
2013 */
2014 skb_condense(skb);
2015
2016 skb_dst_drop(skb);
2017
2018 if (unlikely(tcp_checksum_complete(skb))) {
2019 bh_unlock_sock(sk);
2020 trace_tcp_bad_csum(skb);
2021 *reason = SKB_DROP_REASON_TCP_CSUM;
2022 __TCP_INC_STATS(sock_net(sk), TCP_MIB_CSUMERRORS);
2023 __TCP_INC_STATS(sock_net(sk), TCP_MIB_INERRS);
2024 return true;
2025 }
2026
2027 /* Attempt coalescing to last skb in backlog, even if we are
2028 * above the limits.
2029 * This is okay because skb capacity is limited to MAX_SKB_FRAGS.
2030 */
2031 th = (const struct tcphdr *)skb->data;
2032 hdrlen = th->doff * 4;
2033
2034 tail = sk->sk_backlog.tail;
2035 if (!tail)
2036 goto no_coalesce;
2037 thtail = (struct tcphdr *)tail->data;
2038
2039 if (TCP_SKB_CB(tail)->end_seq != TCP_SKB_CB(skb)->seq ||
2040 TCP_SKB_CB(tail)->ip_dsfield != TCP_SKB_CB(skb)->ip_dsfield ||
2041 ((TCP_SKB_CB(tail)->tcp_flags |
2042 TCP_SKB_CB(skb)->tcp_flags) & (TCPHDR_SYN | TCPHDR_RST | TCPHDR_URG)) ||
2043 !((TCP_SKB_CB(tail)->tcp_flags &
2044 TCP_SKB_CB(skb)->tcp_flags) & TCPHDR_ACK) ||
2045 ((TCP_SKB_CB(tail)->tcp_flags ^
2046 TCP_SKB_CB(skb)->tcp_flags) & (TCPHDR_ECE | TCPHDR_CWR)) ||
2047#ifdef CONFIG_TLS_DEVICE
2048 tail->decrypted != skb->decrypted ||
2049#endif
2050 !mptcp_skb_can_collapse(tail, skb) ||
2051 thtail->doff != th->doff ||
2052 memcmp(thtail + 1, th + 1, hdrlen - sizeof(*th)))
2053 goto no_coalesce;
2054
2055 __skb_pull(skb, hdrlen);
2056
2057 shinfo = skb_shinfo(skb);
2058 gso_size = shinfo->gso_size ?: skb->len;
2059 gso_segs = shinfo->gso_segs ?: 1;
2060
2061 shinfo = skb_shinfo(tail);
2062 tail_gso_size = shinfo->gso_size ?: (tail->len - hdrlen);
2063 tail_gso_segs = shinfo->gso_segs ?: 1;
2064
2065 if (skb_try_coalesce(tail, skb, &fragstolen, &delta)) {
2066 TCP_SKB_CB(tail)->end_seq = TCP_SKB_CB(skb)->end_seq;
2067
2068 if (likely(!before(TCP_SKB_CB(skb)->ack_seq, TCP_SKB_CB(tail)->ack_seq))) {
2069 TCP_SKB_CB(tail)->ack_seq = TCP_SKB_CB(skb)->ack_seq;
2070 thtail->window = th->window;
2071 }
2072
2073 /* We have to update both TCP_SKB_CB(tail)->tcp_flags and
2074 * thtail->fin, so that the fast path in tcp_rcv_established()
2075 * is not entered if we append a packet with a FIN.
2076 * SYN, RST, URG are not present.
2077 * ACK is set on both packets.
2078 * PSH : we do not really care in TCP stack,
2079 * at least for 'GRO' packets.
2080 */
2081 thtail->fin |= th->fin;
2082 TCP_SKB_CB(tail)->tcp_flags |= TCP_SKB_CB(skb)->tcp_flags;
2083
2084 if (TCP_SKB_CB(skb)->has_rxtstamp) {
2085 TCP_SKB_CB(tail)->has_rxtstamp = true;
2086 tail->tstamp = skb->tstamp;
2087 skb_hwtstamps(tail)->hwtstamp = skb_hwtstamps(skb)->hwtstamp;
2088 }
2089
2090 /* Not as strict as GRO. We only need to carry mss max value */
2091 shinfo->gso_size = max(gso_size, tail_gso_size);
2092 shinfo->gso_segs = min_t(u32, gso_segs + tail_gso_segs, 0xFFFF);
2093
2094 sk->sk_backlog.len += delta;
2095 __NET_INC_STATS(sock_net(sk),
2096 LINUX_MIB_TCPBACKLOGCOALESCE);
2097 kfree_skb_partial(skb, fragstolen);
2098 return false;
2099 }
2100 __skb_push(skb, hdrlen);
2101
2102no_coalesce:
2103 limit = (u32)READ_ONCE(sk->sk_rcvbuf) + (u32)(READ_ONCE(sk->sk_sndbuf) >> 1);
2104
2105 /* Only socket owner can try to collapse/prune rx queues
2106 * to reduce memory overhead, so add a little headroom here.
2107 * Few sockets backlog are possibly concurrently non empty.
2108 */
2109 limit += 64 * 1024;
2110
2111 if (unlikely(sk_add_backlog(sk, skb, limit))) {
2112 bh_unlock_sock(sk);
2113 *reason = SKB_DROP_REASON_SOCKET_BACKLOG;
2114 __NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPBACKLOGDROP);
2115 return true;
2116 }
2117 return false;
2118}
2119EXPORT_SYMBOL(tcp_add_backlog);
2120
2121int tcp_filter(struct sock *sk, struct sk_buff *skb)
2122{
2123 struct tcphdr *th = (struct tcphdr *)skb->data;
2124
2125 return sk_filter_trim_cap(sk, skb, th->doff * 4);
2126}
2127EXPORT_SYMBOL(tcp_filter);
2128
2129static void tcp_v4_restore_cb(struct sk_buff *skb)
2130{
2131 memmove(IPCB(skb), &TCP_SKB_CB(skb)->header.h4,
2132 sizeof(struct inet_skb_parm));
2133}
2134
2135static void tcp_v4_fill_cb(struct sk_buff *skb, const struct iphdr *iph,
2136 const struct tcphdr *th)
2137{
2138 /* This is tricky : We move IPCB at its correct location into TCP_SKB_CB()
2139 * barrier() makes sure compiler wont play fool^Waliasing games.
2140 */
2141 memmove(&TCP_SKB_CB(skb)->header.h4, IPCB(skb),
2142 sizeof(struct inet_skb_parm));
2143 barrier();
2144
2145 TCP_SKB_CB(skb)->seq = ntohl(th->seq);
2146 TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
2147 skb->len - th->doff * 4);
2148 TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
2149 TCP_SKB_CB(skb)->tcp_flags = tcp_flag_byte(th);
2150 TCP_SKB_CB(skb)->tcp_tw_isn = 0;
2151 TCP_SKB_CB(skb)->ip_dsfield = ipv4_get_dsfield(iph);
2152 TCP_SKB_CB(skb)->sacked = 0;
2153 TCP_SKB_CB(skb)->has_rxtstamp =
2154 skb->tstamp || skb_hwtstamps(skb)->hwtstamp;
2155}
2156
2157/*
2158 * From tcp_input.c
2159 */
2160
2161int tcp_v4_rcv(struct sk_buff *skb)
2162{
2163 struct net *net = dev_net(skb->dev);
2164 enum skb_drop_reason drop_reason;
2165 int sdif = inet_sdif(skb);
2166 int dif = inet_iif(skb);
2167 const struct iphdr *iph;
2168 const struct tcphdr *th;
2169 bool refcounted;
2170 struct sock *sk;
2171 int ret;
2172
2173 drop_reason = SKB_DROP_REASON_NOT_SPECIFIED;
2174 if (skb->pkt_type != PACKET_HOST)
2175 goto discard_it;
2176
2177 /* Count it even if it's bad */
2178 __TCP_INC_STATS(net, TCP_MIB_INSEGS);
2179
2180 if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
2181 goto discard_it;
2182
2183 th = (const struct tcphdr *)skb->data;
2184
2185 if (unlikely(th->doff < sizeof(struct tcphdr) / 4)) {
2186 drop_reason = SKB_DROP_REASON_PKT_TOO_SMALL;
2187 goto bad_packet;
2188 }
2189 if (!pskb_may_pull(skb, th->doff * 4))
2190 goto discard_it;
2191
2192 /* An explanation is required here, I think.
2193 * Packet length and doff are validated by header prediction,
2194 * provided case of th->doff==0 is eliminated.
2195 * So, we defer the checks. */
2196
2197 if (skb_checksum_init(skb, IPPROTO_TCP, inet_compute_pseudo))
2198 goto csum_error;
2199
2200 th = (const struct tcphdr *)skb->data;
2201 iph = ip_hdr(skb);
2202lookup:
2203 sk = __inet_lookup_skb(net->ipv4.tcp_death_row.hashinfo,
2204 skb, __tcp_hdrlen(th), th->source,
2205 th->dest, sdif, &refcounted);
2206 if (!sk)
2207 goto no_tcp_socket;
2208
2209process:
2210 if (sk->sk_state == TCP_TIME_WAIT)
2211 goto do_time_wait;
2212
2213 if (sk->sk_state == TCP_NEW_SYN_RECV) {
2214 struct request_sock *req = inet_reqsk(sk);
2215 bool req_stolen = false;
2216 struct sock *nsk;
2217
2218 sk = req->rsk_listener;
2219 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
2220 drop_reason = SKB_DROP_REASON_XFRM_POLICY;
2221 else
2222 drop_reason = tcp_inbound_hash(sk, req, skb,
2223 &iph->saddr, &iph->daddr,
2224 AF_INET, dif, sdif);
2225 if (unlikely(drop_reason)) {
2226 sk_drops_add(sk, skb);
2227 reqsk_put(req);
2228 goto discard_it;
2229 }
2230 if (tcp_checksum_complete(skb)) {
2231 reqsk_put(req);
2232 goto csum_error;
2233 }
2234 if (unlikely(sk->sk_state != TCP_LISTEN)) {
2235 nsk = reuseport_migrate_sock(sk, req_to_sk(req), skb);
2236 if (!nsk) {
2237 inet_csk_reqsk_queue_drop_and_put(sk, req);
2238 goto lookup;
2239 }
2240 sk = nsk;
2241 /* reuseport_migrate_sock() has already held one sk_refcnt
2242 * before returning.
2243 */
2244 } else {
2245 /* We own a reference on the listener, increase it again
2246 * as we might lose it too soon.
2247 */
2248 sock_hold(sk);
2249 }
2250 refcounted = true;
2251 nsk = NULL;
2252 if (!tcp_filter(sk, skb)) {
2253 th = (const struct tcphdr *)skb->data;
2254 iph = ip_hdr(skb);
2255 tcp_v4_fill_cb(skb, iph, th);
2256 nsk = tcp_check_req(sk, skb, req, false, &req_stolen);
2257 } else {
2258 drop_reason = SKB_DROP_REASON_SOCKET_FILTER;
2259 }
2260 if (!nsk) {
2261 reqsk_put(req);
2262 if (req_stolen) {
2263 /* Another cpu got exclusive access to req
2264 * and created a full blown socket.
2265 * Try to feed this packet to this socket
2266 * instead of discarding it.
2267 */
2268 tcp_v4_restore_cb(skb);
2269 sock_put(sk);
2270 goto lookup;
2271 }
2272 goto discard_and_relse;
2273 }
2274 nf_reset_ct(skb);
2275 if (nsk == sk) {
2276 reqsk_put(req);
2277 tcp_v4_restore_cb(skb);
2278 } else if (tcp_child_process(sk, nsk, skb)) {
2279 tcp_v4_send_reset(nsk, skb);
2280 goto discard_and_relse;
2281 } else {
2282 sock_put(sk);
2283 return 0;
2284 }
2285 }
2286
2287 if (static_branch_unlikely(&ip4_min_ttl)) {
2288 /* min_ttl can be changed concurrently from do_ip_setsockopt() */
2289 if (unlikely(iph->ttl < READ_ONCE(inet_sk(sk)->min_ttl))) {
2290 __NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP);
2291 drop_reason = SKB_DROP_REASON_TCP_MINTTL;
2292 goto discard_and_relse;
2293 }
2294 }
2295
2296 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb)) {
2297 drop_reason = SKB_DROP_REASON_XFRM_POLICY;
2298 goto discard_and_relse;
2299 }
2300
2301 drop_reason = tcp_inbound_hash(sk, NULL, skb, &iph->saddr, &iph->daddr,
2302 AF_INET, dif, sdif);
2303 if (drop_reason)
2304 goto discard_and_relse;
2305
2306 nf_reset_ct(skb);
2307
2308 if (tcp_filter(sk, skb)) {
2309 drop_reason = SKB_DROP_REASON_SOCKET_FILTER;
2310 goto discard_and_relse;
2311 }
2312 th = (const struct tcphdr *)skb->data;
2313 iph = ip_hdr(skb);
2314 tcp_v4_fill_cb(skb, iph, th);
2315
2316 skb->dev = NULL;
2317
2318 if (sk->sk_state == TCP_LISTEN) {
2319 ret = tcp_v4_do_rcv(sk, skb);
2320 goto put_and_return;
2321 }
2322
2323 sk_incoming_cpu_update(sk);
2324
2325 bh_lock_sock_nested(sk);
2326 tcp_segs_in(tcp_sk(sk), skb);
2327 ret = 0;
2328 if (!sock_owned_by_user(sk)) {
2329 ret = tcp_v4_do_rcv(sk, skb);
2330 } else {
2331 if (tcp_add_backlog(sk, skb, &drop_reason))
2332 goto discard_and_relse;
2333 }
2334 bh_unlock_sock(sk);
2335
2336put_and_return:
2337 if (refcounted)
2338 sock_put(sk);
2339
2340 return ret;
2341
2342no_tcp_socket:
2343 drop_reason = SKB_DROP_REASON_NO_SOCKET;
2344 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
2345 goto discard_it;
2346
2347 tcp_v4_fill_cb(skb, iph, th);
2348
2349 if (tcp_checksum_complete(skb)) {
2350csum_error:
2351 drop_reason = SKB_DROP_REASON_TCP_CSUM;
2352 trace_tcp_bad_csum(skb);
2353 __TCP_INC_STATS(net, TCP_MIB_CSUMERRORS);
2354bad_packet:
2355 __TCP_INC_STATS(net, TCP_MIB_INERRS);
2356 } else {
2357 tcp_v4_send_reset(NULL, skb);
2358 }
2359
2360discard_it:
2361 SKB_DR_OR(drop_reason, NOT_SPECIFIED);
2362 /* Discard frame. */
2363 kfree_skb_reason(skb, drop_reason);
2364 return 0;
2365
2366discard_and_relse:
2367 sk_drops_add(sk, skb);
2368 if (refcounted)
2369 sock_put(sk);
2370 goto discard_it;
2371
2372do_time_wait:
2373 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
2374 drop_reason = SKB_DROP_REASON_XFRM_POLICY;
2375 inet_twsk_put(inet_twsk(sk));
2376 goto discard_it;
2377 }
2378
2379 tcp_v4_fill_cb(skb, iph, th);
2380
2381 if (tcp_checksum_complete(skb)) {
2382 inet_twsk_put(inet_twsk(sk));
2383 goto csum_error;
2384 }
2385 switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) {
2386 case TCP_TW_SYN: {
2387 struct sock *sk2 = inet_lookup_listener(net,
2388 net->ipv4.tcp_death_row.hashinfo,
2389 skb, __tcp_hdrlen(th),
2390 iph->saddr, th->source,
2391 iph->daddr, th->dest,
2392 inet_iif(skb),
2393 sdif);
2394 if (sk2) {
2395 inet_twsk_deschedule_put(inet_twsk(sk));
2396 sk = sk2;
2397 tcp_v4_restore_cb(skb);
2398 refcounted = false;
2399 goto process;
2400 }
2401 }
2402 /* to ACK */
2403 fallthrough;
2404 case TCP_TW_ACK:
2405 tcp_v4_timewait_ack(sk, skb);
2406 break;
2407 case TCP_TW_RST:
2408 tcp_v4_send_reset(sk, skb);
2409 inet_twsk_deschedule_put(inet_twsk(sk));
2410 goto discard_it;
2411 case TCP_TW_SUCCESS:;
2412 }
2413 goto discard_it;
2414}
2415
2416static struct timewait_sock_ops tcp_timewait_sock_ops = {
2417 .twsk_obj_size = sizeof(struct tcp_timewait_sock),
2418 .twsk_unique = tcp_twsk_unique,
2419 .twsk_destructor= tcp_twsk_destructor,
2420};
2421
2422void inet_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb)
2423{
2424 struct dst_entry *dst = skb_dst(skb);
2425
2426 if (dst && dst_hold_safe(dst)) {
2427 rcu_assign_pointer(sk->sk_rx_dst, dst);
2428 sk->sk_rx_dst_ifindex = skb->skb_iif;
2429 }
2430}
2431EXPORT_SYMBOL(inet_sk_rx_dst_set);
2432
2433const struct inet_connection_sock_af_ops ipv4_specific = {
2434 .queue_xmit = ip_queue_xmit,
2435 .send_check = tcp_v4_send_check,
2436 .rebuild_header = inet_sk_rebuild_header,
2437 .sk_rx_dst_set = inet_sk_rx_dst_set,
2438 .conn_request = tcp_v4_conn_request,
2439 .syn_recv_sock = tcp_v4_syn_recv_sock,
2440 .net_header_len = sizeof(struct iphdr),
2441 .setsockopt = ip_setsockopt,
2442 .getsockopt = ip_getsockopt,
2443 .addr2sockaddr = inet_csk_addr2sockaddr,
2444 .sockaddr_len = sizeof(struct sockaddr_in),
2445 .mtu_reduced = tcp_v4_mtu_reduced,
2446};
2447EXPORT_SYMBOL(ipv4_specific);
2448
2449#if defined(CONFIG_TCP_MD5SIG) || defined(CONFIG_TCP_AO)
2450static const struct tcp_sock_af_ops tcp_sock_ipv4_specific = {
2451#ifdef CONFIG_TCP_MD5SIG
2452 .md5_lookup = tcp_v4_md5_lookup,
2453 .calc_md5_hash = tcp_v4_md5_hash_skb,
2454 .md5_parse = tcp_v4_parse_md5_keys,
2455#endif
2456#ifdef CONFIG_TCP_AO
2457 .ao_lookup = tcp_v4_ao_lookup,
2458 .calc_ao_hash = tcp_v4_ao_hash_skb,
2459 .ao_parse = tcp_v4_parse_ao,
2460 .ao_calc_key_sk = tcp_v4_ao_calc_key_sk,
2461#endif
2462};
2463#endif
2464
2465/* NOTE: A lot of things set to zero explicitly by call to
2466 * sk_alloc() so need not be done here.
2467 */
2468static int tcp_v4_init_sock(struct sock *sk)
2469{
2470 struct inet_connection_sock *icsk = inet_csk(sk);
2471
2472 tcp_init_sock(sk);
2473
2474 icsk->icsk_af_ops = &ipv4_specific;
2475
2476#if defined(CONFIG_TCP_MD5SIG) || defined(CONFIG_TCP_AO)
2477 tcp_sk(sk)->af_specific = &tcp_sock_ipv4_specific;
2478#endif
2479
2480 return 0;
2481}
2482
2483#ifdef CONFIG_TCP_MD5SIG
2484static void tcp_md5sig_info_free_rcu(struct rcu_head *head)
2485{
2486 struct tcp_md5sig_info *md5sig;
2487
2488 md5sig = container_of(head, struct tcp_md5sig_info, rcu);
2489 kfree(md5sig);
2490 static_branch_slow_dec_deferred(&tcp_md5_needed);
2491 tcp_md5_release_sigpool();
2492}
2493#endif
2494
2495void tcp_v4_destroy_sock(struct sock *sk)
2496{
2497 struct tcp_sock *tp = tcp_sk(sk);
2498
2499 trace_tcp_destroy_sock(sk);
2500
2501 tcp_clear_xmit_timers(sk);
2502
2503 tcp_cleanup_congestion_control(sk);
2504
2505 tcp_cleanup_ulp(sk);
2506
2507 /* Cleanup up the write buffer. */
2508 tcp_write_queue_purge(sk);
2509
2510 /* Check if we want to disable active TFO */
2511 tcp_fastopen_active_disable_ofo_check(sk);
2512
2513 /* Cleans up our, hopefully empty, out_of_order_queue. */
2514 skb_rbtree_purge(&tp->out_of_order_queue);
2515
2516#ifdef CONFIG_TCP_MD5SIG
2517 /* Clean up the MD5 key list, if any */
2518 if (tp->md5sig_info) {
2519 struct tcp_md5sig_info *md5sig;
2520
2521 md5sig = rcu_dereference_protected(tp->md5sig_info, 1);
2522 tcp_clear_md5_list(sk);
2523 call_rcu(&md5sig->rcu, tcp_md5sig_info_free_rcu);
2524 rcu_assign_pointer(tp->md5sig_info, NULL);
2525 }
2526#endif
2527 tcp_ao_destroy_sock(sk, false);
2528
2529 /* Clean up a referenced TCP bind bucket. */
2530 if (inet_csk(sk)->icsk_bind_hash)
2531 inet_put_port(sk);
2532
2533 BUG_ON(rcu_access_pointer(tp->fastopen_rsk));
2534
2535 /* If socket is aborted during connect operation */
2536 tcp_free_fastopen_req(tp);
2537 tcp_fastopen_destroy_cipher(sk);
2538 tcp_saved_syn_free(tp);
2539
2540 sk_sockets_allocated_dec(sk);
2541}
2542EXPORT_SYMBOL(tcp_v4_destroy_sock);
2543
2544#ifdef CONFIG_PROC_FS
2545/* Proc filesystem TCP sock list dumping. */
2546
2547static unsigned short seq_file_family(const struct seq_file *seq);
2548
2549static bool seq_sk_match(struct seq_file *seq, const struct sock *sk)
2550{
2551 unsigned short family = seq_file_family(seq);
2552
2553 /* AF_UNSPEC is used as a match all */
2554 return ((family == AF_UNSPEC || family == sk->sk_family) &&
2555 net_eq(sock_net(sk), seq_file_net(seq)));
2556}
2557
2558/* Find a non empty bucket (starting from st->bucket)
2559 * and return the first sk from it.
2560 */
2561static void *listening_get_first(struct seq_file *seq)
2562{
2563 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo;
2564 struct tcp_iter_state *st = seq->private;
2565
2566 st->offset = 0;
2567 for (; st->bucket <= hinfo->lhash2_mask; st->bucket++) {
2568 struct inet_listen_hashbucket *ilb2;
2569 struct hlist_nulls_node *node;
2570 struct sock *sk;
2571
2572 ilb2 = &hinfo->lhash2[st->bucket];
2573 if (hlist_nulls_empty(&ilb2->nulls_head))
2574 continue;
2575
2576 spin_lock(&ilb2->lock);
2577 sk_nulls_for_each(sk, node, &ilb2->nulls_head) {
2578 if (seq_sk_match(seq, sk))
2579 return sk;
2580 }
2581 spin_unlock(&ilb2->lock);
2582 }
2583
2584 return NULL;
2585}
2586
2587/* Find the next sk of "cur" within the same bucket (i.e. st->bucket).
2588 * If "cur" is the last one in the st->bucket,
2589 * call listening_get_first() to return the first sk of the next
2590 * non empty bucket.
2591 */
2592static void *listening_get_next(struct seq_file *seq, void *cur)
2593{
2594 struct tcp_iter_state *st = seq->private;
2595 struct inet_listen_hashbucket *ilb2;
2596 struct hlist_nulls_node *node;
2597 struct inet_hashinfo *hinfo;
2598 struct sock *sk = cur;
2599
2600 ++st->num;
2601 ++st->offset;
2602
2603 sk = sk_nulls_next(sk);
2604 sk_nulls_for_each_from(sk, node) {
2605 if (seq_sk_match(seq, sk))
2606 return sk;
2607 }
2608
2609 hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo;
2610 ilb2 = &hinfo->lhash2[st->bucket];
2611 spin_unlock(&ilb2->lock);
2612 ++st->bucket;
2613 return listening_get_first(seq);
2614}
2615
2616static void *listening_get_idx(struct seq_file *seq, loff_t *pos)
2617{
2618 struct tcp_iter_state *st = seq->private;
2619 void *rc;
2620
2621 st->bucket = 0;
2622 st->offset = 0;
2623 rc = listening_get_first(seq);
2624
2625 while (rc && *pos) {
2626 rc = listening_get_next(seq, rc);
2627 --*pos;
2628 }
2629 return rc;
2630}
2631
2632static inline bool empty_bucket(struct inet_hashinfo *hinfo,
2633 const struct tcp_iter_state *st)
2634{
2635 return hlist_nulls_empty(&hinfo->ehash[st->bucket].chain);
2636}
2637
2638/*
2639 * Get first established socket starting from bucket given in st->bucket.
2640 * If st->bucket is zero, the very first socket in the hash is returned.
2641 */
2642static void *established_get_first(struct seq_file *seq)
2643{
2644 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo;
2645 struct tcp_iter_state *st = seq->private;
2646
2647 st->offset = 0;
2648 for (; st->bucket <= hinfo->ehash_mask; ++st->bucket) {
2649 struct sock *sk;
2650 struct hlist_nulls_node *node;
2651 spinlock_t *lock = inet_ehash_lockp(hinfo, st->bucket);
2652
2653 cond_resched();
2654
2655 /* Lockless fast path for the common case of empty buckets */
2656 if (empty_bucket(hinfo, st))
2657 continue;
2658
2659 spin_lock_bh(lock);
2660 sk_nulls_for_each(sk, node, &hinfo->ehash[st->bucket].chain) {
2661 if (seq_sk_match(seq, sk))
2662 return sk;
2663 }
2664 spin_unlock_bh(lock);
2665 }
2666
2667 return NULL;
2668}
2669
2670static void *established_get_next(struct seq_file *seq, void *cur)
2671{
2672 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo;
2673 struct tcp_iter_state *st = seq->private;
2674 struct hlist_nulls_node *node;
2675 struct sock *sk = cur;
2676
2677 ++st->num;
2678 ++st->offset;
2679
2680 sk = sk_nulls_next(sk);
2681
2682 sk_nulls_for_each_from(sk, node) {
2683 if (seq_sk_match(seq, sk))
2684 return sk;
2685 }
2686
2687 spin_unlock_bh(inet_ehash_lockp(hinfo, st->bucket));
2688 ++st->bucket;
2689 return established_get_first(seq);
2690}
2691
2692static void *established_get_idx(struct seq_file *seq, loff_t pos)
2693{
2694 struct tcp_iter_state *st = seq->private;
2695 void *rc;
2696
2697 st->bucket = 0;
2698 rc = established_get_first(seq);
2699
2700 while (rc && pos) {
2701 rc = established_get_next(seq, rc);
2702 --pos;
2703 }
2704 return rc;
2705}
2706
2707static void *tcp_get_idx(struct seq_file *seq, loff_t pos)
2708{
2709 void *rc;
2710 struct tcp_iter_state *st = seq->private;
2711
2712 st->state = TCP_SEQ_STATE_LISTENING;
2713 rc = listening_get_idx(seq, &pos);
2714
2715 if (!rc) {
2716 st->state = TCP_SEQ_STATE_ESTABLISHED;
2717 rc = established_get_idx(seq, pos);
2718 }
2719
2720 return rc;
2721}
2722
2723static void *tcp_seek_last_pos(struct seq_file *seq)
2724{
2725 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo;
2726 struct tcp_iter_state *st = seq->private;
2727 int bucket = st->bucket;
2728 int offset = st->offset;
2729 int orig_num = st->num;
2730 void *rc = NULL;
2731
2732 switch (st->state) {
2733 case TCP_SEQ_STATE_LISTENING:
2734 if (st->bucket > hinfo->lhash2_mask)
2735 break;
2736 rc = listening_get_first(seq);
2737 while (offset-- && rc && bucket == st->bucket)
2738 rc = listening_get_next(seq, rc);
2739 if (rc)
2740 break;
2741 st->bucket = 0;
2742 st->state = TCP_SEQ_STATE_ESTABLISHED;
2743 fallthrough;
2744 case TCP_SEQ_STATE_ESTABLISHED:
2745 if (st->bucket > hinfo->ehash_mask)
2746 break;
2747 rc = established_get_first(seq);
2748 while (offset-- && rc && bucket == st->bucket)
2749 rc = established_get_next(seq, rc);
2750 }
2751
2752 st->num = orig_num;
2753
2754 return rc;
2755}
2756
2757void *tcp_seq_start(struct seq_file *seq, loff_t *pos)
2758{
2759 struct tcp_iter_state *st = seq->private;
2760 void *rc;
2761
2762 if (*pos && *pos == st->last_pos) {
2763 rc = tcp_seek_last_pos(seq);
2764 if (rc)
2765 goto out;
2766 }
2767
2768 st->state = TCP_SEQ_STATE_LISTENING;
2769 st->num = 0;
2770 st->bucket = 0;
2771 st->offset = 0;
2772 rc = *pos ? tcp_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
2773
2774out:
2775 st->last_pos = *pos;
2776 return rc;
2777}
2778EXPORT_SYMBOL(tcp_seq_start);
2779
2780void *tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2781{
2782 struct tcp_iter_state *st = seq->private;
2783 void *rc = NULL;
2784
2785 if (v == SEQ_START_TOKEN) {
2786 rc = tcp_get_idx(seq, 0);
2787 goto out;
2788 }
2789
2790 switch (st->state) {
2791 case TCP_SEQ_STATE_LISTENING:
2792 rc = listening_get_next(seq, v);
2793 if (!rc) {
2794 st->state = TCP_SEQ_STATE_ESTABLISHED;
2795 st->bucket = 0;
2796 st->offset = 0;
2797 rc = established_get_first(seq);
2798 }
2799 break;
2800 case TCP_SEQ_STATE_ESTABLISHED:
2801 rc = established_get_next(seq, v);
2802 break;
2803 }
2804out:
2805 ++*pos;
2806 st->last_pos = *pos;
2807 return rc;
2808}
2809EXPORT_SYMBOL(tcp_seq_next);
2810
2811void tcp_seq_stop(struct seq_file *seq, void *v)
2812{
2813 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo;
2814 struct tcp_iter_state *st = seq->private;
2815
2816 switch (st->state) {
2817 case TCP_SEQ_STATE_LISTENING:
2818 if (v != SEQ_START_TOKEN)
2819 spin_unlock(&hinfo->lhash2[st->bucket].lock);
2820 break;
2821 case TCP_SEQ_STATE_ESTABLISHED:
2822 if (v)
2823 spin_unlock_bh(inet_ehash_lockp(hinfo, st->bucket));
2824 break;
2825 }
2826}
2827EXPORT_SYMBOL(tcp_seq_stop);
2828
2829static void get_openreq4(const struct request_sock *req,
2830 struct seq_file *f, int i)
2831{
2832 const struct inet_request_sock *ireq = inet_rsk(req);
2833 long delta = req->rsk_timer.expires - jiffies;
2834
2835 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2836 " %02X %08X:%08X %02X:%08lX %08X %5u %8d %u %d %pK",
2837 i,
2838 ireq->ir_loc_addr,
2839 ireq->ir_num,
2840 ireq->ir_rmt_addr,
2841 ntohs(ireq->ir_rmt_port),
2842 TCP_SYN_RECV,
2843 0, 0, /* could print option size, but that is af dependent. */
2844 1, /* timers active (only the expire timer) */
2845 jiffies_delta_to_clock_t(delta),
2846 req->num_timeout,
2847 from_kuid_munged(seq_user_ns(f),
2848 sock_i_uid(req->rsk_listener)),
2849 0, /* non standard timer */
2850 0, /* open_requests have no inode */
2851 0,
2852 req);
2853}
2854
2855static void get_tcp4_sock(struct sock *sk, struct seq_file *f, int i)
2856{
2857 int timer_active;
2858 unsigned long timer_expires;
2859 const struct tcp_sock *tp = tcp_sk(sk);
2860 const struct inet_connection_sock *icsk = inet_csk(sk);
2861 const struct inet_sock *inet = inet_sk(sk);
2862 const struct fastopen_queue *fastopenq = &icsk->icsk_accept_queue.fastopenq;
2863 __be32 dest = inet->inet_daddr;
2864 __be32 src = inet->inet_rcv_saddr;
2865 __u16 destp = ntohs(inet->inet_dport);
2866 __u16 srcp = ntohs(inet->inet_sport);
2867 int rx_queue;
2868 int state;
2869
2870 if (icsk->icsk_pending == ICSK_TIME_RETRANS ||
2871 icsk->icsk_pending == ICSK_TIME_REO_TIMEOUT ||
2872 icsk->icsk_pending == ICSK_TIME_LOSS_PROBE) {
2873 timer_active = 1;
2874 timer_expires = icsk->icsk_timeout;
2875 } else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
2876 timer_active = 4;
2877 timer_expires = icsk->icsk_timeout;
2878 } else if (timer_pending(&sk->sk_timer)) {
2879 timer_active = 2;
2880 timer_expires = sk->sk_timer.expires;
2881 } else {
2882 timer_active = 0;
2883 timer_expires = jiffies;
2884 }
2885
2886 state = inet_sk_state_load(sk);
2887 if (state == TCP_LISTEN)
2888 rx_queue = READ_ONCE(sk->sk_ack_backlog);
2889 else
2890 /* Because we don't lock the socket,
2891 * we might find a transient negative value.
2892 */
2893 rx_queue = max_t(int, READ_ONCE(tp->rcv_nxt) -
2894 READ_ONCE(tp->copied_seq), 0);
2895
2896 seq_printf(f, "%4d: %08X:%04X %08X:%04X %02X %08X:%08X %02X:%08lX "
2897 "%08X %5u %8d %lu %d %pK %lu %lu %u %u %d",
2898 i, src, srcp, dest, destp, state,
2899 READ_ONCE(tp->write_seq) - tp->snd_una,
2900 rx_queue,
2901 timer_active,
2902 jiffies_delta_to_clock_t(timer_expires - jiffies),
2903 icsk->icsk_retransmits,
2904 from_kuid_munged(seq_user_ns(f), sock_i_uid(sk)),
2905 icsk->icsk_probes_out,
2906 sock_i_ino(sk),
2907 refcount_read(&sk->sk_refcnt), sk,
2908 jiffies_to_clock_t(icsk->icsk_rto),
2909 jiffies_to_clock_t(icsk->icsk_ack.ato),
2910 (icsk->icsk_ack.quick << 1) | inet_csk_in_pingpong_mode(sk),
2911 tcp_snd_cwnd(tp),
2912 state == TCP_LISTEN ?
2913 fastopenq->max_qlen :
2914 (tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh));
2915}
2916
2917static void get_timewait4_sock(const struct inet_timewait_sock *tw,
2918 struct seq_file *f, int i)
2919{
2920 long delta = tw->tw_timer.expires - jiffies;
2921 __be32 dest, src;
2922 __u16 destp, srcp;
2923
2924 dest = tw->tw_daddr;
2925 src = tw->tw_rcv_saddr;
2926 destp = ntohs(tw->tw_dport);
2927 srcp = ntohs(tw->tw_sport);
2928
2929 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2930 " %02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK",
2931 i, src, srcp, dest, destp, tw->tw_substate, 0, 0,
2932 3, jiffies_delta_to_clock_t(delta), 0, 0, 0, 0,
2933 refcount_read(&tw->tw_refcnt), tw);
2934}
2935
2936#define TMPSZ 150
2937
2938static int tcp4_seq_show(struct seq_file *seq, void *v)
2939{
2940 struct tcp_iter_state *st;
2941 struct sock *sk = v;
2942
2943 seq_setwidth(seq, TMPSZ - 1);
2944 if (v == SEQ_START_TOKEN) {
2945 seq_puts(seq, " sl local_address rem_address st tx_queue "
2946 "rx_queue tr tm->when retrnsmt uid timeout "
2947 "inode");
2948 goto out;
2949 }
2950 st = seq->private;
2951
2952 if (sk->sk_state == TCP_TIME_WAIT)
2953 get_timewait4_sock(v, seq, st->num);
2954 else if (sk->sk_state == TCP_NEW_SYN_RECV)
2955 get_openreq4(v, seq, st->num);
2956 else
2957 get_tcp4_sock(v, seq, st->num);
2958out:
2959 seq_pad(seq, '\n');
2960 return 0;
2961}
2962
2963#ifdef CONFIG_BPF_SYSCALL
2964struct bpf_tcp_iter_state {
2965 struct tcp_iter_state state;
2966 unsigned int cur_sk;
2967 unsigned int end_sk;
2968 unsigned int max_sk;
2969 struct sock **batch;
2970 bool st_bucket_done;
2971};
2972
2973struct bpf_iter__tcp {
2974 __bpf_md_ptr(struct bpf_iter_meta *, meta);
2975 __bpf_md_ptr(struct sock_common *, sk_common);
2976 uid_t uid __aligned(8);
2977};
2978
2979static int tcp_prog_seq_show(struct bpf_prog *prog, struct bpf_iter_meta *meta,
2980 struct sock_common *sk_common, uid_t uid)
2981{
2982 struct bpf_iter__tcp ctx;
2983
2984 meta->seq_num--; /* skip SEQ_START_TOKEN */
2985 ctx.meta = meta;
2986 ctx.sk_common = sk_common;
2987 ctx.uid = uid;
2988 return bpf_iter_run_prog(prog, &ctx);
2989}
2990
2991static void bpf_iter_tcp_put_batch(struct bpf_tcp_iter_state *iter)
2992{
2993 while (iter->cur_sk < iter->end_sk)
2994 sock_gen_put(iter->batch[iter->cur_sk++]);
2995}
2996
2997static int bpf_iter_tcp_realloc_batch(struct bpf_tcp_iter_state *iter,
2998 unsigned int new_batch_sz)
2999{
3000 struct sock **new_batch;
3001
3002 new_batch = kvmalloc(sizeof(*new_batch) * new_batch_sz,
3003 GFP_USER | __GFP_NOWARN);
3004 if (!new_batch)
3005 return -ENOMEM;
3006
3007 bpf_iter_tcp_put_batch(iter);
3008 kvfree(iter->batch);
3009 iter->batch = new_batch;
3010 iter->max_sk = new_batch_sz;
3011
3012 return 0;
3013}
3014
3015static unsigned int bpf_iter_tcp_listening_batch(struct seq_file *seq,
3016 struct sock *start_sk)
3017{
3018 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo;
3019 struct bpf_tcp_iter_state *iter = seq->private;
3020 struct tcp_iter_state *st = &iter->state;
3021 struct hlist_nulls_node *node;
3022 unsigned int expected = 1;
3023 struct sock *sk;
3024
3025 sock_hold(start_sk);
3026 iter->batch[iter->end_sk++] = start_sk;
3027
3028 sk = sk_nulls_next(start_sk);
3029 sk_nulls_for_each_from(sk, node) {
3030 if (seq_sk_match(seq, sk)) {
3031 if (iter->end_sk < iter->max_sk) {
3032 sock_hold(sk);
3033 iter->batch[iter->end_sk++] = sk;
3034 }
3035 expected++;
3036 }
3037 }
3038 spin_unlock(&hinfo->lhash2[st->bucket].lock);
3039
3040 return expected;
3041}
3042
3043static unsigned int bpf_iter_tcp_established_batch(struct seq_file *seq,
3044 struct sock *start_sk)
3045{
3046 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo;
3047 struct bpf_tcp_iter_state *iter = seq->private;
3048 struct tcp_iter_state *st = &iter->state;
3049 struct hlist_nulls_node *node;
3050 unsigned int expected = 1;
3051 struct sock *sk;
3052
3053 sock_hold(start_sk);
3054 iter->batch[iter->end_sk++] = start_sk;
3055
3056 sk = sk_nulls_next(start_sk);
3057 sk_nulls_for_each_from(sk, node) {
3058 if (seq_sk_match(seq, sk)) {
3059 if (iter->end_sk < iter->max_sk) {
3060 sock_hold(sk);
3061 iter->batch[iter->end_sk++] = sk;
3062 }
3063 expected++;
3064 }
3065 }
3066 spin_unlock_bh(inet_ehash_lockp(hinfo, st->bucket));
3067
3068 return expected;
3069}
3070
3071static struct sock *bpf_iter_tcp_batch(struct seq_file *seq)
3072{
3073 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo;
3074 struct bpf_tcp_iter_state *iter = seq->private;
3075 struct tcp_iter_state *st = &iter->state;
3076 unsigned int expected;
3077 bool resized = false;
3078 struct sock *sk;
3079
3080 /* The st->bucket is done. Directly advance to the next
3081 * bucket instead of having the tcp_seek_last_pos() to skip
3082 * one by one in the current bucket and eventually find out
3083 * it has to advance to the next bucket.
3084 */
3085 if (iter->st_bucket_done) {
3086 st->offset = 0;
3087 st->bucket++;
3088 if (st->state == TCP_SEQ_STATE_LISTENING &&
3089 st->bucket > hinfo->lhash2_mask) {
3090 st->state = TCP_SEQ_STATE_ESTABLISHED;
3091 st->bucket = 0;
3092 }
3093 }
3094
3095again:
3096 /* Get a new batch */
3097 iter->cur_sk = 0;
3098 iter->end_sk = 0;
3099 iter->st_bucket_done = false;
3100
3101 sk = tcp_seek_last_pos(seq);
3102 if (!sk)
3103 return NULL; /* Done */
3104
3105 if (st->state == TCP_SEQ_STATE_LISTENING)
3106 expected = bpf_iter_tcp_listening_batch(seq, sk);
3107 else
3108 expected = bpf_iter_tcp_established_batch(seq, sk);
3109
3110 if (iter->end_sk == expected) {
3111 iter->st_bucket_done = true;
3112 return sk;
3113 }
3114
3115 if (!resized && !bpf_iter_tcp_realloc_batch(iter, expected * 3 / 2)) {
3116 resized = true;
3117 goto again;
3118 }
3119
3120 return sk;
3121}
3122
3123static void *bpf_iter_tcp_seq_start(struct seq_file *seq, loff_t *pos)
3124{
3125 /* bpf iter does not support lseek, so it always
3126 * continue from where it was stop()-ped.
3127 */
3128 if (*pos)
3129 return bpf_iter_tcp_batch(seq);
3130
3131 return SEQ_START_TOKEN;
3132}
3133
3134static void *bpf_iter_tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
3135{
3136 struct bpf_tcp_iter_state *iter = seq->private;
3137 struct tcp_iter_state *st = &iter->state;
3138 struct sock *sk;
3139
3140 /* Whenever seq_next() is called, the iter->cur_sk is
3141 * done with seq_show(), so advance to the next sk in
3142 * the batch.
3143 */
3144 if (iter->cur_sk < iter->end_sk) {
3145 /* Keeping st->num consistent in tcp_iter_state.
3146 * bpf_iter_tcp does not use st->num.
3147 * meta.seq_num is used instead.
3148 */
3149 st->num++;
3150 /* Move st->offset to the next sk in the bucket such that
3151 * the future start() will resume at st->offset in
3152 * st->bucket. See tcp_seek_last_pos().
3153 */
3154 st->offset++;
3155 sock_gen_put(iter->batch[iter->cur_sk++]);
3156 }
3157
3158 if (iter->cur_sk < iter->end_sk)
3159 sk = iter->batch[iter->cur_sk];
3160 else
3161 sk = bpf_iter_tcp_batch(seq);
3162
3163 ++*pos;
3164 /* Keeping st->last_pos consistent in tcp_iter_state.
3165 * bpf iter does not do lseek, so st->last_pos always equals to *pos.
3166 */
3167 st->last_pos = *pos;
3168 return sk;
3169}
3170
3171static int bpf_iter_tcp_seq_show(struct seq_file *seq, void *v)
3172{
3173 struct bpf_iter_meta meta;
3174 struct bpf_prog *prog;
3175 struct sock *sk = v;
3176 uid_t uid;
3177 int ret;
3178
3179 if (v == SEQ_START_TOKEN)
3180 return 0;
3181
3182 if (sk_fullsock(sk))
3183 lock_sock(sk);
3184
3185 if (unlikely(sk_unhashed(sk))) {
3186 ret = SEQ_SKIP;
3187 goto unlock;
3188 }
3189
3190 if (sk->sk_state == TCP_TIME_WAIT) {
3191 uid = 0;
3192 } else if (sk->sk_state == TCP_NEW_SYN_RECV) {
3193 const struct request_sock *req = v;
3194
3195 uid = from_kuid_munged(seq_user_ns(seq),
3196 sock_i_uid(req->rsk_listener));
3197 } else {
3198 uid = from_kuid_munged(seq_user_ns(seq), sock_i_uid(sk));
3199 }
3200
3201 meta.seq = seq;
3202 prog = bpf_iter_get_info(&meta, false);
3203 ret = tcp_prog_seq_show(prog, &meta, v, uid);
3204
3205unlock:
3206 if (sk_fullsock(sk))
3207 release_sock(sk);
3208 return ret;
3209
3210}
3211
3212static void bpf_iter_tcp_seq_stop(struct seq_file *seq, void *v)
3213{
3214 struct bpf_tcp_iter_state *iter = seq->private;
3215 struct bpf_iter_meta meta;
3216 struct bpf_prog *prog;
3217
3218 if (!v) {
3219 meta.seq = seq;
3220 prog = bpf_iter_get_info(&meta, true);
3221 if (prog)
3222 (void)tcp_prog_seq_show(prog, &meta, v, 0);
3223 }
3224
3225 if (iter->cur_sk < iter->end_sk) {
3226 bpf_iter_tcp_put_batch(iter);
3227 iter->st_bucket_done = false;
3228 }
3229}
3230
3231static const struct seq_operations bpf_iter_tcp_seq_ops = {
3232 .show = bpf_iter_tcp_seq_show,
3233 .start = bpf_iter_tcp_seq_start,
3234 .next = bpf_iter_tcp_seq_next,
3235 .stop = bpf_iter_tcp_seq_stop,
3236};
3237#endif
3238static unsigned short seq_file_family(const struct seq_file *seq)
3239{
3240 const struct tcp_seq_afinfo *afinfo;
3241
3242#ifdef CONFIG_BPF_SYSCALL
3243 /* Iterated from bpf_iter. Let the bpf prog to filter instead. */
3244 if (seq->op == &bpf_iter_tcp_seq_ops)
3245 return AF_UNSPEC;
3246#endif
3247
3248 /* Iterated from proc fs */
3249 afinfo = pde_data(file_inode(seq->file));
3250 return afinfo->family;
3251}
3252
3253static const struct seq_operations tcp4_seq_ops = {
3254 .show = tcp4_seq_show,
3255 .start = tcp_seq_start,
3256 .next = tcp_seq_next,
3257 .stop = tcp_seq_stop,
3258};
3259
3260static struct tcp_seq_afinfo tcp4_seq_afinfo = {
3261 .family = AF_INET,
3262};
3263
3264static int __net_init tcp4_proc_init_net(struct net *net)
3265{
3266 if (!proc_create_net_data("tcp", 0444, net->proc_net, &tcp4_seq_ops,
3267 sizeof(struct tcp_iter_state), &tcp4_seq_afinfo))
3268 return -ENOMEM;
3269 return 0;
3270}
3271
3272static void __net_exit tcp4_proc_exit_net(struct net *net)
3273{
3274 remove_proc_entry("tcp", net->proc_net);
3275}
3276
3277static struct pernet_operations tcp4_net_ops = {
3278 .init = tcp4_proc_init_net,
3279 .exit = tcp4_proc_exit_net,
3280};
3281
3282int __init tcp4_proc_init(void)
3283{
3284 return register_pernet_subsys(&tcp4_net_ops);
3285}
3286
3287void tcp4_proc_exit(void)
3288{
3289 unregister_pernet_subsys(&tcp4_net_ops);
3290}
3291#endif /* CONFIG_PROC_FS */
3292
3293/* @wake is one when sk_stream_write_space() calls us.
3294 * This sends EPOLLOUT only if notsent_bytes is half the limit.
3295 * This mimics the strategy used in sock_def_write_space().
3296 */
3297bool tcp_stream_memory_free(const struct sock *sk, int wake)
3298{
3299 const struct tcp_sock *tp = tcp_sk(sk);
3300 u32 notsent_bytes = READ_ONCE(tp->write_seq) -
3301 READ_ONCE(tp->snd_nxt);
3302
3303 return (notsent_bytes << wake) < tcp_notsent_lowat(tp);
3304}
3305EXPORT_SYMBOL(tcp_stream_memory_free);
3306
3307struct proto tcp_prot = {
3308 .name = "TCP",
3309 .owner = THIS_MODULE,
3310 .close = tcp_close,
3311 .pre_connect = tcp_v4_pre_connect,
3312 .connect = tcp_v4_connect,
3313 .disconnect = tcp_disconnect,
3314 .accept = inet_csk_accept,
3315 .ioctl = tcp_ioctl,
3316 .init = tcp_v4_init_sock,
3317 .destroy = tcp_v4_destroy_sock,
3318 .shutdown = tcp_shutdown,
3319 .setsockopt = tcp_setsockopt,
3320 .getsockopt = tcp_getsockopt,
3321 .bpf_bypass_getsockopt = tcp_bpf_bypass_getsockopt,
3322 .keepalive = tcp_set_keepalive,
3323 .recvmsg = tcp_recvmsg,
3324 .sendmsg = tcp_sendmsg,
3325 .splice_eof = tcp_splice_eof,
3326 .backlog_rcv = tcp_v4_do_rcv,
3327 .release_cb = tcp_release_cb,
3328 .hash = inet_hash,
3329 .unhash = inet_unhash,
3330 .get_port = inet_csk_get_port,
3331 .put_port = inet_put_port,
3332#ifdef CONFIG_BPF_SYSCALL
3333 .psock_update_sk_prot = tcp_bpf_update_proto,
3334#endif
3335 .enter_memory_pressure = tcp_enter_memory_pressure,
3336 .leave_memory_pressure = tcp_leave_memory_pressure,
3337 .stream_memory_free = tcp_stream_memory_free,
3338 .sockets_allocated = &tcp_sockets_allocated,
3339 .orphan_count = &tcp_orphan_count,
3340
3341 .memory_allocated = &tcp_memory_allocated,
3342 .per_cpu_fw_alloc = &tcp_memory_per_cpu_fw_alloc,
3343
3344 .memory_pressure = &tcp_memory_pressure,
3345 .sysctl_mem = sysctl_tcp_mem,
3346 .sysctl_wmem_offset = offsetof(struct net, ipv4.sysctl_tcp_wmem),
3347 .sysctl_rmem_offset = offsetof(struct net, ipv4.sysctl_tcp_rmem),
3348 .max_header = MAX_TCP_HEADER,
3349 .obj_size = sizeof(struct tcp_sock),
3350 .slab_flags = SLAB_TYPESAFE_BY_RCU,
3351 .twsk_prot = &tcp_timewait_sock_ops,
3352 .rsk_prot = &tcp_request_sock_ops,
3353 .h.hashinfo = NULL,
3354 .no_autobind = true,
3355 .diag_destroy = tcp_abort,
3356};
3357EXPORT_SYMBOL(tcp_prot);
3358
3359static void __net_exit tcp_sk_exit(struct net *net)
3360{
3361 if (net->ipv4.tcp_congestion_control)
3362 bpf_module_put(net->ipv4.tcp_congestion_control,
3363 net->ipv4.tcp_congestion_control->owner);
3364}
3365
3366static void __net_init tcp_set_hashinfo(struct net *net)
3367{
3368 struct inet_hashinfo *hinfo;
3369 unsigned int ehash_entries;
3370 struct net *old_net;
3371
3372 if (net_eq(net, &init_net))
3373 goto fallback;
3374
3375 old_net = current->nsproxy->net_ns;
3376 ehash_entries = READ_ONCE(old_net->ipv4.sysctl_tcp_child_ehash_entries);
3377 if (!ehash_entries)
3378 goto fallback;
3379
3380 ehash_entries = roundup_pow_of_two(ehash_entries);
3381 hinfo = inet_pernet_hashinfo_alloc(&tcp_hashinfo, ehash_entries);
3382 if (!hinfo) {
3383 pr_warn("Failed to allocate TCP ehash (entries: %u) "
3384 "for a netns, fallback to the global one\n",
3385 ehash_entries);
3386fallback:
3387 hinfo = &tcp_hashinfo;
3388 ehash_entries = tcp_hashinfo.ehash_mask + 1;
3389 }
3390
3391 net->ipv4.tcp_death_row.hashinfo = hinfo;
3392 net->ipv4.tcp_death_row.sysctl_max_tw_buckets = ehash_entries / 2;
3393 net->ipv4.sysctl_max_syn_backlog = max(128U, ehash_entries / 128);
3394}
3395
3396static int __net_init tcp_sk_init(struct net *net)
3397{
3398 net->ipv4.sysctl_tcp_ecn = 2;
3399 net->ipv4.sysctl_tcp_ecn_fallback = 1;
3400
3401 net->ipv4.sysctl_tcp_base_mss = TCP_BASE_MSS;
3402 net->ipv4.sysctl_tcp_min_snd_mss = TCP_MIN_SND_MSS;
3403 net->ipv4.sysctl_tcp_probe_threshold = TCP_PROBE_THRESHOLD;
3404 net->ipv4.sysctl_tcp_probe_interval = TCP_PROBE_INTERVAL;
3405 net->ipv4.sysctl_tcp_mtu_probe_floor = TCP_MIN_SND_MSS;
3406
3407 net->ipv4.sysctl_tcp_keepalive_time = TCP_KEEPALIVE_TIME;
3408 net->ipv4.sysctl_tcp_keepalive_probes = TCP_KEEPALIVE_PROBES;
3409 net->ipv4.sysctl_tcp_keepalive_intvl = TCP_KEEPALIVE_INTVL;
3410
3411 net->ipv4.sysctl_tcp_syn_retries = TCP_SYN_RETRIES;
3412 net->ipv4.sysctl_tcp_synack_retries = TCP_SYNACK_RETRIES;
3413 net->ipv4.sysctl_tcp_syncookies = 1;
3414 net->ipv4.sysctl_tcp_reordering = TCP_FASTRETRANS_THRESH;
3415 net->ipv4.sysctl_tcp_retries1 = TCP_RETR1;
3416 net->ipv4.sysctl_tcp_retries2 = TCP_RETR2;
3417 net->ipv4.sysctl_tcp_orphan_retries = 0;
3418 net->ipv4.sysctl_tcp_fin_timeout = TCP_FIN_TIMEOUT;
3419 net->ipv4.sysctl_tcp_notsent_lowat = UINT_MAX;
3420 net->ipv4.sysctl_tcp_tw_reuse = 2;
3421 net->ipv4.sysctl_tcp_no_ssthresh_metrics_save = 1;
3422
3423 refcount_set(&net->ipv4.tcp_death_row.tw_refcount, 1);
3424 tcp_set_hashinfo(net);
3425
3426 net->ipv4.sysctl_tcp_sack = 1;
3427 net->ipv4.sysctl_tcp_window_scaling = 1;
3428 net->ipv4.sysctl_tcp_timestamps = 1;
3429 net->ipv4.sysctl_tcp_early_retrans = 3;
3430 net->ipv4.sysctl_tcp_recovery = TCP_RACK_LOSS_DETECTION;
3431 net->ipv4.sysctl_tcp_slow_start_after_idle = 1; /* By default, RFC2861 behavior. */
3432 net->ipv4.sysctl_tcp_retrans_collapse = 1;
3433 net->ipv4.sysctl_tcp_max_reordering = 300;
3434 net->ipv4.sysctl_tcp_dsack = 1;
3435 net->ipv4.sysctl_tcp_app_win = 31;
3436 net->ipv4.sysctl_tcp_adv_win_scale = 1;
3437 net->ipv4.sysctl_tcp_frto = 2;
3438 net->ipv4.sysctl_tcp_moderate_rcvbuf = 1;
3439 /* This limits the percentage of the congestion window which we
3440 * will allow a single TSO frame to consume. Building TSO frames
3441 * which are too large can cause TCP streams to be bursty.
3442 */
3443 net->ipv4.sysctl_tcp_tso_win_divisor = 3;
3444 /* Default TSQ limit of 16 TSO segments */
3445 net->ipv4.sysctl_tcp_limit_output_bytes = 16 * 65536;
3446
3447 /* rfc5961 challenge ack rate limiting, per net-ns, disabled by default. */
3448 net->ipv4.sysctl_tcp_challenge_ack_limit = INT_MAX;
3449
3450 net->ipv4.sysctl_tcp_min_tso_segs = 2;
3451 net->ipv4.sysctl_tcp_tso_rtt_log = 9; /* 2^9 = 512 usec */
3452 net->ipv4.sysctl_tcp_min_rtt_wlen = 300;
3453 net->ipv4.sysctl_tcp_autocorking = 1;
3454 net->ipv4.sysctl_tcp_invalid_ratelimit = HZ/2;
3455 net->ipv4.sysctl_tcp_pacing_ss_ratio = 200;
3456 net->ipv4.sysctl_tcp_pacing_ca_ratio = 120;
3457 if (net != &init_net) {
3458 memcpy(net->ipv4.sysctl_tcp_rmem,
3459 init_net.ipv4.sysctl_tcp_rmem,
3460 sizeof(init_net.ipv4.sysctl_tcp_rmem));
3461 memcpy(net->ipv4.sysctl_tcp_wmem,
3462 init_net.ipv4.sysctl_tcp_wmem,
3463 sizeof(init_net.ipv4.sysctl_tcp_wmem));
3464 }
3465 net->ipv4.sysctl_tcp_comp_sack_delay_ns = NSEC_PER_MSEC;
3466 net->ipv4.sysctl_tcp_comp_sack_slack_ns = 100 * NSEC_PER_USEC;
3467 net->ipv4.sysctl_tcp_comp_sack_nr = 44;
3468 net->ipv4.sysctl_tcp_backlog_ack_defer = 1;
3469 net->ipv4.sysctl_tcp_fastopen = TFO_CLIENT_ENABLE;
3470 net->ipv4.sysctl_tcp_fastopen_blackhole_timeout = 0;
3471 atomic_set(&net->ipv4.tfo_active_disable_times, 0);
3472
3473 /* Set default values for PLB */
3474 net->ipv4.sysctl_tcp_plb_enabled = 0; /* Disabled by default */
3475 net->ipv4.sysctl_tcp_plb_idle_rehash_rounds = 3;
3476 net->ipv4.sysctl_tcp_plb_rehash_rounds = 12;
3477 net->ipv4.sysctl_tcp_plb_suspend_rto_sec = 60;
3478 /* Default congestion threshold for PLB to mark a round is 50% */
3479 net->ipv4.sysctl_tcp_plb_cong_thresh = (1 << TCP_PLB_SCALE) / 2;
3480
3481 /* Reno is always built in */
3482 if (!net_eq(net, &init_net) &&
3483 bpf_try_module_get(init_net.ipv4.tcp_congestion_control,
3484 init_net.ipv4.tcp_congestion_control->owner))
3485 net->ipv4.tcp_congestion_control = init_net.ipv4.tcp_congestion_control;
3486 else
3487 net->ipv4.tcp_congestion_control = &tcp_reno;
3488
3489 net->ipv4.sysctl_tcp_syn_linear_timeouts = 4;
3490 net->ipv4.sysctl_tcp_shrink_window = 0;
3491
3492 net->ipv4.sysctl_tcp_pingpong_thresh = 1;
3493
3494 return 0;
3495}
3496
3497static void __net_exit tcp_sk_exit_batch(struct list_head *net_exit_list)
3498{
3499 struct net *net;
3500
3501 tcp_twsk_purge(net_exit_list, AF_INET);
3502
3503 list_for_each_entry(net, net_exit_list, exit_list) {
3504 inet_pernet_hashinfo_free(net->ipv4.tcp_death_row.hashinfo);
3505 WARN_ON_ONCE(!refcount_dec_and_test(&net->ipv4.tcp_death_row.tw_refcount));
3506 tcp_fastopen_ctx_destroy(net);
3507 }
3508}
3509
3510static struct pernet_operations __net_initdata tcp_sk_ops = {
3511 .init = tcp_sk_init,
3512 .exit = tcp_sk_exit,
3513 .exit_batch = tcp_sk_exit_batch,
3514};
3515
3516#if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS)
3517DEFINE_BPF_ITER_FUNC(tcp, struct bpf_iter_meta *meta,
3518 struct sock_common *sk_common, uid_t uid)
3519
3520#define INIT_BATCH_SZ 16
3521
3522static int bpf_iter_init_tcp(void *priv_data, struct bpf_iter_aux_info *aux)
3523{
3524 struct bpf_tcp_iter_state *iter = priv_data;
3525 int err;
3526
3527 err = bpf_iter_init_seq_net(priv_data, aux);
3528 if (err)
3529 return err;
3530
3531 err = bpf_iter_tcp_realloc_batch(iter, INIT_BATCH_SZ);
3532 if (err) {
3533 bpf_iter_fini_seq_net(priv_data);
3534 return err;
3535 }
3536
3537 return 0;
3538}
3539
3540static void bpf_iter_fini_tcp(void *priv_data)
3541{
3542 struct bpf_tcp_iter_state *iter = priv_data;
3543
3544 bpf_iter_fini_seq_net(priv_data);
3545 kvfree(iter->batch);
3546}
3547
3548static const struct bpf_iter_seq_info tcp_seq_info = {
3549 .seq_ops = &bpf_iter_tcp_seq_ops,
3550 .init_seq_private = bpf_iter_init_tcp,
3551 .fini_seq_private = bpf_iter_fini_tcp,
3552 .seq_priv_size = sizeof(struct bpf_tcp_iter_state),
3553};
3554
3555static const struct bpf_func_proto *
3556bpf_iter_tcp_get_func_proto(enum bpf_func_id func_id,
3557 const struct bpf_prog *prog)
3558{
3559 switch (func_id) {
3560 case BPF_FUNC_setsockopt:
3561 return &bpf_sk_setsockopt_proto;
3562 case BPF_FUNC_getsockopt:
3563 return &bpf_sk_getsockopt_proto;
3564 default:
3565 return NULL;
3566 }
3567}
3568
3569static struct bpf_iter_reg tcp_reg_info = {
3570 .target = "tcp",
3571 .ctx_arg_info_size = 1,
3572 .ctx_arg_info = {
3573 { offsetof(struct bpf_iter__tcp, sk_common),
3574 PTR_TO_BTF_ID_OR_NULL | PTR_TRUSTED },
3575 },
3576 .get_func_proto = bpf_iter_tcp_get_func_proto,
3577 .seq_info = &tcp_seq_info,
3578};
3579
3580static void __init bpf_iter_register(void)
3581{
3582 tcp_reg_info.ctx_arg_info[0].btf_id = btf_sock_ids[BTF_SOCK_TYPE_SOCK_COMMON];
3583 if (bpf_iter_reg_target(&tcp_reg_info))
3584 pr_warn("Warning: could not register bpf iterator tcp\n");
3585}
3586
3587#endif
3588
3589void __init tcp_v4_init(void)
3590{
3591 int cpu, res;
3592
3593 for_each_possible_cpu(cpu) {
3594 struct sock *sk;
3595
3596 res = inet_ctl_sock_create(&sk, PF_INET, SOCK_RAW,
3597 IPPROTO_TCP, &init_net);
3598 if (res)
3599 panic("Failed to create the TCP control socket.\n");
3600 sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
3601
3602 /* Please enforce IP_DF and IPID==0 for RST and
3603 * ACK sent in SYN-RECV and TIME-WAIT state.
3604 */
3605 inet_sk(sk)->pmtudisc = IP_PMTUDISC_DO;
3606
3607 per_cpu(ipv4_tcp_sk, cpu) = sk;
3608 }
3609 if (register_pernet_subsys(&tcp_sk_ops))
3610 panic("Failed to create the TCP control socket.\n");
3611
3612#if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS)
3613 bpf_iter_register();
3614#endif
3615}