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