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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * INET An implementation of the TCP/IP protocol suite for the LINUX
4 * operating system. INET is implemented using the BSD Socket
5 * interface as the means of communication with the user level.
6 *
7 * Implementation of the Transmission Control Protocol(TCP).
8 *
9 * IPv4 specific functions
10 *
11 * code split from:
12 * linux/ipv4/tcp.c
13 * linux/ipv4/tcp_input.c
14 * linux/ipv4/tcp_output.c
15 *
16 * See tcp.c for author information
17 */
18
19/*
20 * Changes:
21 * David S. Miller : New socket lookup architecture.
22 * This code is dedicated to John Dyson.
23 * David S. Miller : Change semantics of established hash,
24 * half is devoted to TIME_WAIT sockets
25 * and the rest go in the other half.
26 * Andi Kleen : Add support for syncookies and fixed
27 * some bugs: ip options weren't passed to
28 * the TCP layer, missed a check for an
29 * ACK bit.
30 * Andi Kleen : Implemented fast path mtu discovery.
31 * Fixed many serious bugs in the
32 * request_sock handling and moved
33 * most of it into the af independent code.
34 * Added tail drop and some other bugfixes.
35 * Added new listen semantics.
36 * Mike McLagan : Routing by source
37 * Juan Jose Ciarlante: ip_dynaddr bits
38 * Andi Kleen: various fixes.
39 * Vitaly E. Lavrov : Transparent proxy revived after year
40 * coma.
41 * Andi Kleen : Fix new listen.
42 * Andi Kleen : Fix accept error reporting.
43 * YOSHIFUJI Hideaki @USAGI and: Support IPV6_V6ONLY socket option, which
44 * Alexey Kuznetsov allow both IPv4 and IPv6 sockets to bind
45 * a single port at the same time.
46 */
47
48#define pr_fmt(fmt) "TCP: " fmt
49
50#include <linux/bottom_half.h>
51#include <linux/types.h>
52#include <linux/fcntl.h>
53#include <linux/module.h>
54#include <linux/random.h>
55#include <linux/cache.h>
56#include <linux/jhash.h>
57#include <linux/init.h>
58#include <linux/times.h>
59#include <linux/slab.h>
60
61#include <net/net_namespace.h>
62#include <net/icmp.h>
63#include <net/inet_hashtables.h>
64#include <net/tcp.h>
65#include <net/transp_v6.h>
66#include <net/ipv6.h>
67#include <net/inet_common.h>
68#include <net/timewait_sock.h>
69#include <net/xfrm.h>
70#include <net/secure_seq.h>
71#include <net/busy_poll.h>
72
73#include <linux/inet.h>
74#include <linux/ipv6.h>
75#include <linux/stddef.h>
76#include <linux/proc_fs.h>
77#include <linux/seq_file.h>
78#include <linux/inetdevice.h>
79#include <linux/btf_ids.h>
80
81#include <crypto/hash.h>
82#include <linux/scatterlist.h>
83
84#include <trace/events/tcp.h>
85
86#ifdef CONFIG_TCP_MD5SIG
87static int tcp_v4_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key,
88 __be32 daddr, __be32 saddr, const struct tcphdr *th);
89#endif
90
91struct inet_hashinfo tcp_hashinfo;
92EXPORT_SYMBOL(tcp_hashinfo);
93
94static DEFINE_PER_CPU(struct sock *, ipv4_tcp_sk);
95
96static u32 tcp_v4_init_seq(const struct sk_buff *skb)
97{
98 return secure_tcp_seq(ip_hdr(skb)->daddr,
99 ip_hdr(skb)->saddr,
100 tcp_hdr(skb)->dest,
101 tcp_hdr(skb)->source);
102}
103
104static u32 tcp_v4_init_ts_off(const struct net *net, const struct sk_buff *skb)
105{
106 return secure_tcp_ts_off(net, ip_hdr(skb)->daddr, ip_hdr(skb)->saddr);
107}
108
109int tcp_twsk_unique(struct sock *sk, struct sock *sktw, void *twp)
110{
111 int reuse = READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_tw_reuse);
112 const struct inet_timewait_sock *tw = inet_twsk(sktw);
113 const struct tcp_timewait_sock *tcptw = tcp_twsk(sktw);
114 struct tcp_sock *tp = tcp_sk(sk);
115
116 if (reuse == 2) {
117 /* Still does not detect *everything* that goes through
118 * lo, since we require a loopback src or dst address
119 * or direct binding to 'lo' interface.
120 */
121 bool loopback = false;
122 if (tw->tw_bound_dev_if == LOOPBACK_IFINDEX)
123 loopback = true;
124#if IS_ENABLED(CONFIG_IPV6)
125 if (tw->tw_family == AF_INET6) {
126 if (ipv6_addr_loopback(&tw->tw_v6_daddr) ||
127 ipv6_addr_v4mapped_loopback(&tw->tw_v6_daddr) ||
128 ipv6_addr_loopback(&tw->tw_v6_rcv_saddr) ||
129 ipv6_addr_v4mapped_loopback(&tw->tw_v6_rcv_saddr))
130 loopback = true;
131 } else
132#endif
133 {
134 if (ipv4_is_loopback(tw->tw_daddr) ||
135 ipv4_is_loopback(tw->tw_rcv_saddr))
136 loopback = true;
137 }
138 if (!loopback)
139 reuse = 0;
140 }
141
142 /* With PAWS, it is safe from the viewpoint
143 of data integrity. Even without PAWS it is safe provided sequence
144 spaces do not overlap i.e. at data rates <= 80Mbit/sec.
145
146 Actually, the idea is close to VJ's one, only timestamp cache is
147 held not per host, but per port pair and TW bucket is used as state
148 holder.
149
150 If TW bucket has been already destroyed we fall back to VJ's scheme
151 and use initial timestamp retrieved from peer table.
152 */
153 if (tcptw->tw_ts_recent_stamp &&
154 (!twp || (reuse && time_after32(ktime_get_seconds(),
155 tcptw->tw_ts_recent_stamp)))) {
156 /* In case of repair and re-using TIME-WAIT sockets we still
157 * want to be sure that it is safe as above but honor the
158 * sequence numbers and time stamps set as part of the repair
159 * process.
160 *
161 * Without this check re-using a TIME-WAIT socket with TCP
162 * repair would accumulate a -1 on the repair assigned
163 * sequence number. The first time it is reused the sequence
164 * is -1, the second time -2, etc. This fixes that issue
165 * without appearing to create any others.
166 */
167 if (likely(!tp->repair)) {
168 u32 seq = tcptw->tw_snd_nxt + 65535 + 2;
169
170 if (!seq)
171 seq = 1;
172 WRITE_ONCE(tp->write_seq, seq);
173 tp->rx_opt.ts_recent = tcptw->tw_ts_recent;
174 tp->rx_opt.ts_recent_stamp = tcptw->tw_ts_recent_stamp;
175 }
176 sock_hold(sktw);
177 return 1;
178 }
179
180 return 0;
181}
182EXPORT_SYMBOL_GPL(tcp_twsk_unique);
183
184static int tcp_v4_pre_connect(struct sock *sk, struct sockaddr *uaddr,
185 int addr_len)
186{
187 /* This check is replicated from tcp_v4_connect() and intended to
188 * prevent BPF program called below from accessing bytes that are out
189 * of the bound specified by user in addr_len.
190 */
191 if (addr_len < sizeof(struct sockaddr_in))
192 return -EINVAL;
193
194 sock_owned_by_me(sk);
195
196 return BPF_CGROUP_RUN_PROG_INET4_CONNECT(sk, uaddr);
197}
198
199/* This will initiate an outgoing connection. */
200int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
201{
202 struct sockaddr_in *usin = (struct sockaddr_in *)uaddr;
203 struct inet_timewait_death_row *tcp_death_row;
204 struct inet_sock *inet = inet_sk(sk);
205 struct tcp_sock *tp = tcp_sk(sk);
206 struct ip_options_rcu *inet_opt;
207 struct net *net = sock_net(sk);
208 __be16 orig_sport, orig_dport;
209 __be32 daddr, nexthop;
210 struct flowi4 *fl4;
211 struct rtable *rt;
212 int err;
213
214 if (addr_len < sizeof(struct sockaddr_in))
215 return -EINVAL;
216
217 if (usin->sin_family != AF_INET)
218 return -EAFNOSUPPORT;
219
220 nexthop = daddr = usin->sin_addr.s_addr;
221 inet_opt = rcu_dereference_protected(inet->inet_opt,
222 lockdep_sock_is_held(sk));
223 if (inet_opt && inet_opt->opt.srr) {
224 if (!daddr)
225 return -EINVAL;
226 nexthop = inet_opt->opt.faddr;
227 }
228
229 orig_sport = inet->inet_sport;
230 orig_dport = usin->sin_port;
231 fl4 = &inet->cork.fl.u.ip4;
232 rt = ip_route_connect(fl4, nexthop, inet->inet_saddr,
233 sk->sk_bound_dev_if, IPPROTO_TCP, orig_sport,
234 orig_dport, sk);
235 if (IS_ERR(rt)) {
236 err = PTR_ERR(rt);
237 if (err == -ENETUNREACH)
238 IP_INC_STATS(net, IPSTATS_MIB_OUTNOROUTES);
239 return err;
240 }
241
242 if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) {
243 ip_rt_put(rt);
244 return -ENETUNREACH;
245 }
246
247 if (!inet_opt || !inet_opt->opt.srr)
248 daddr = fl4->daddr;
249
250 tcp_death_row = &sock_net(sk)->ipv4.tcp_death_row;
251
252 if (!inet->inet_saddr) {
253 err = inet_bhash2_update_saddr(sk, &fl4->saddr, AF_INET);
254 if (err) {
255 ip_rt_put(rt);
256 return err;
257 }
258 } else {
259 sk_rcv_saddr_set(sk, inet->inet_saddr);
260 }
261
262 if (tp->rx_opt.ts_recent_stamp && inet->inet_daddr != daddr) {
263 /* Reset inherited state */
264 tp->rx_opt.ts_recent = 0;
265 tp->rx_opt.ts_recent_stamp = 0;
266 if (likely(!tp->repair))
267 WRITE_ONCE(tp->write_seq, 0);
268 }
269
270 inet->inet_dport = usin->sin_port;
271 sk_daddr_set(sk, daddr);
272
273 inet_csk(sk)->icsk_ext_hdr_len = 0;
274 if (inet_opt)
275 inet_csk(sk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
276
277 tp->rx_opt.mss_clamp = TCP_MSS_DEFAULT;
278
279 /* Socket identity is still unknown (sport may be zero).
280 * However we set state to SYN-SENT and not releasing socket
281 * lock select source port, enter ourselves into the hash tables and
282 * complete initialization after this.
283 */
284 tcp_set_state(sk, TCP_SYN_SENT);
285 err = inet_hash_connect(tcp_death_row, sk);
286 if (err)
287 goto failure;
288
289 sk_set_txhash(sk);
290
291 rt = ip_route_newports(fl4, rt, orig_sport, orig_dport,
292 inet->inet_sport, inet->inet_dport, sk);
293 if (IS_ERR(rt)) {
294 err = PTR_ERR(rt);
295 rt = NULL;
296 goto failure;
297 }
298 /* OK, now commit destination to socket. */
299 sk->sk_gso_type = SKB_GSO_TCPV4;
300 sk_setup_caps(sk, &rt->dst);
301 rt = NULL;
302
303 if (likely(!tp->repair)) {
304 if (!tp->write_seq)
305 WRITE_ONCE(tp->write_seq,
306 secure_tcp_seq(inet->inet_saddr,
307 inet->inet_daddr,
308 inet->inet_sport,
309 usin->sin_port));
310 tp->tsoffset = secure_tcp_ts_off(net, inet->inet_saddr,
311 inet->inet_daddr);
312 }
313
314 inet->inet_id = get_random_u16();
315
316 if (tcp_fastopen_defer_connect(sk, &err))
317 return err;
318 if (err)
319 goto failure;
320
321 err = tcp_connect(sk);
322
323 if (err)
324 goto failure;
325
326 return 0;
327
328failure:
329 /*
330 * This unhashes the socket and releases the local port,
331 * if necessary.
332 */
333 tcp_set_state(sk, TCP_CLOSE);
334 inet_bhash2_reset_saddr(sk);
335 ip_rt_put(rt);
336 sk->sk_route_caps = 0;
337 inet->inet_dport = 0;
338 return err;
339}
340EXPORT_SYMBOL(tcp_v4_connect);
341
342/*
343 * This routine reacts to ICMP_FRAG_NEEDED mtu indications as defined in RFC1191.
344 * It can be called through tcp_release_cb() if socket was owned by user
345 * at the time tcp_v4_err() was called to handle ICMP message.
346 */
347void tcp_v4_mtu_reduced(struct sock *sk)
348{
349 struct inet_sock *inet = inet_sk(sk);
350 struct dst_entry *dst;
351 u32 mtu;
352
353 if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE))
354 return;
355 mtu = READ_ONCE(tcp_sk(sk)->mtu_info);
356 dst = inet_csk_update_pmtu(sk, mtu);
357 if (!dst)
358 return;
359
360 /* Something is about to be wrong... Remember soft error
361 * for the case, if this connection will not able to recover.
362 */
363 if (mtu < dst_mtu(dst) && ip_dont_fragment(sk, dst))
364 sk->sk_err_soft = EMSGSIZE;
365
366 mtu = dst_mtu(dst);
367
368 if (inet->pmtudisc != IP_PMTUDISC_DONT &&
369 ip_sk_accept_pmtu(sk) &&
370 inet_csk(sk)->icsk_pmtu_cookie > mtu) {
371 tcp_sync_mss(sk, mtu);
372
373 /* Resend the TCP packet because it's
374 * clear that the old packet has been
375 * dropped. This is the new "fast" path mtu
376 * discovery.
377 */
378 tcp_simple_retransmit(sk);
379 } /* else let the usual retransmit timer handle it */
380}
381EXPORT_SYMBOL(tcp_v4_mtu_reduced);
382
383static void do_redirect(struct sk_buff *skb, struct sock *sk)
384{
385 struct dst_entry *dst = __sk_dst_check(sk, 0);
386
387 if (dst)
388 dst->ops->redirect(dst, sk, skb);
389}
390
391
392/* handle ICMP messages on TCP_NEW_SYN_RECV request sockets */
393void tcp_req_err(struct sock *sk, u32 seq, bool abort)
394{
395 struct request_sock *req = inet_reqsk(sk);
396 struct net *net = sock_net(sk);
397
398 /* ICMPs are not backlogged, hence we cannot get
399 * an established socket here.
400 */
401 if (seq != tcp_rsk(req)->snt_isn) {
402 __NET_INC_STATS(net, LINUX_MIB_OUTOFWINDOWICMPS);
403 } else if (abort) {
404 /*
405 * Still in SYN_RECV, just remove it silently.
406 * There is no good way to pass the error to the newly
407 * created socket, and POSIX does not want network
408 * errors returned from accept().
409 */
410 inet_csk_reqsk_queue_drop(req->rsk_listener, req);
411 tcp_listendrop(req->rsk_listener);
412 }
413 reqsk_put(req);
414}
415EXPORT_SYMBOL(tcp_req_err);
416
417/* TCP-LD (RFC 6069) logic */
418void tcp_ld_RTO_revert(struct sock *sk, u32 seq)
419{
420 struct inet_connection_sock *icsk = inet_csk(sk);
421 struct tcp_sock *tp = tcp_sk(sk);
422 struct sk_buff *skb;
423 s32 remaining;
424 u32 delta_us;
425
426 if (sock_owned_by_user(sk))
427 return;
428
429 if (seq != tp->snd_una || !icsk->icsk_retransmits ||
430 !icsk->icsk_backoff)
431 return;
432
433 skb = tcp_rtx_queue_head(sk);
434 if (WARN_ON_ONCE(!skb))
435 return;
436
437 icsk->icsk_backoff--;
438 icsk->icsk_rto = tp->srtt_us ? __tcp_set_rto(tp) : TCP_TIMEOUT_INIT;
439 icsk->icsk_rto = inet_csk_rto_backoff(icsk, TCP_RTO_MAX);
440
441 tcp_mstamp_refresh(tp);
442 delta_us = (u32)(tp->tcp_mstamp - tcp_skb_timestamp_us(skb));
443 remaining = icsk->icsk_rto - usecs_to_jiffies(delta_us);
444
445 if (remaining > 0) {
446 inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
447 remaining, TCP_RTO_MAX);
448 } else {
449 /* RTO revert clocked out retransmission.
450 * Will retransmit now.
451 */
452 tcp_retransmit_timer(sk);
453 }
454}
455EXPORT_SYMBOL(tcp_ld_RTO_revert);
456
457/*
458 * This routine is called by the ICMP module when it gets some
459 * sort of error condition. If err < 0 then the socket should
460 * be closed and the error returned to the user. If err > 0
461 * it's just the icmp type << 8 | icmp code. After adjustment
462 * header points to the first 8 bytes of the tcp header. We need
463 * to find the appropriate port.
464 *
465 * The locking strategy used here is very "optimistic". When
466 * someone else accesses the socket the ICMP is just dropped
467 * and for some paths there is no check at all.
468 * A more general error queue to queue errors for later handling
469 * is probably better.
470 *
471 */
472
473int tcp_v4_err(struct sk_buff *skb, u32 info)
474{
475 const struct iphdr *iph = (const struct iphdr *)skb->data;
476 struct tcphdr *th = (struct tcphdr *)(skb->data + (iph->ihl << 2));
477 struct tcp_sock *tp;
478 struct inet_sock *inet;
479 const int type = icmp_hdr(skb)->type;
480 const int code = icmp_hdr(skb)->code;
481 struct sock *sk;
482 struct request_sock *fastopen;
483 u32 seq, snd_una;
484 int err;
485 struct net *net = dev_net(skb->dev);
486
487 sk = __inet_lookup_established(net, net->ipv4.tcp_death_row.hashinfo,
488 iph->daddr, th->dest, iph->saddr,
489 ntohs(th->source), inet_iif(skb), 0);
490 if (!sk) {
491 __ICMP_INC_STATS(net, ICMP_MIB_INERRORS);
492 return -ENOENT;
493 }
494 if (sk->sk_state == TCP_TIME_WAIT) {
495 inet_twsk_put(inet_twsk(sk));
496 return 0;
497 }
498 seq = ntohl(th->seq);
499 if (sk->sk_state == TCP_NEW_SYN_RECV) {
500 tcp_req_err(sk, seq, type == ICMP_PARAMETERPROB ||
501 type == ICMP_TIME_EXCEEDED ||
502 (type == ICMP_DEST_UNREACH &&
503 (code == ICMP_NET_UNREACH ||
504 code == ICMP_HOST_UNREACH)));
505 return 0;
506 }
507
508 bh_lock_sock(sk);
509 /* If too many ICMPs get dropped on busy
510 * servers this needs to be solved differently.
511 * We do take care of PMTU discovery (RFC1191) special case :
512 * we can receive locally generated ICMP messages while socket is held.
513 */
514 if (sock_owned_by_user(sk)) {
515 if (!(type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED))
516 __NET_INC_STATS(net, LINUX_MIB_LOCKDROPPEDICMPS);
517 }
518 if (sk->sk_state == TCP_CLOSE)
519 goto out;
520
521 if (static_branch_unlikely(&ip4_min_ttl)) {
522 /* min_ttl can be changed concurrently from do_ip_setsockopt() */
523 if (unlikely(iph->ttl < READ_ONCE(inet_sk(sk)->min_ttl))) {
524 __NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP);
525 goto out;
526 }
527 }
528
529 tp = tcp_sk(sk);
530 /* XXX (TFO) - tp->snd_una should be ISN (tcp_create_openreq_child() */
531 fastopen = rcu_dereference(tp->fastopen_rsk);
532 snd_una = fastopen ? tcp_rsk(fastopen)->snt_isn : tp->snd_una;
533 if (sk->sk_state != TCP_LISTEN &&
534 !between(seq, snd_una, tp->snd_nxt)) {
535 __NET_INC_STATS(net, LINUX_MIB_OUTOFWINDOWICMPS);
536 goto out;
537 }
538
539 switch (type) {
540 case ICMP_REDIRECT:
541 if (!sock_owned_by_user(sk))
542 do_redirect(skb, sk);
543 goto out;
544 case ICMP_SOURCE_QUENCH:
545 /* Just silently ignore these. */
546 goto out;
547 case ICMP_PARAMETERPROB:
548 err = EPROTO;
549 break;
550 case ICMP_DEST_UNREACH:
551 if (code > NR_ICMP_UNREACH)
552 goto out;
553
554 if (code == ICMP_FRAG_NEEDED) { /* PMTU discovery (RFC1191) */
555 /* We are not interested in TCP_LISTEN and open_requests
556 * (SYN-ACKs send out by Linux are always <576bytes so
557 * they should go through unfragmented).
558 */
559 if (sk->sk_state == TCP_LISTEN)
560 goto out;
561
562 WRITE_ONCE(tp->mtu_info, info);
563 if (!sock_owned_by_user(sk)) {
564 tcp_v4_mtu_reduced(sk);
565 } else {
566 if (!test_and_set_bit(TCP_MTU_REDUCED_DEFERRED, &sk->sk_tsq_flags))
567 sock_hold(sk);
568 }
569 goto out;
570 }
571
572 err = icmp_err_convert[code].errno;
573 /* check if this ICMP message allows revert of backoff.
574 * (see RFC 6069)
575 */
576 if (!fastopen &&
577 (code == ICMP_NET_UNREACH || code == ICMP_HOST_UNREACH))
578 tcp_ld_RTO_revert(sk, seq);
579 break;
580 case ICMP_TIME_EXCEEDED:
581 err = EHOSTUNREACH;
582 break;
583 default:
584 goto out;
585 }
586
587 switch (sk->sk_state) {
588 case TCP_SYN_SENT:
589 case TCP_SYN_RECV:
590 /* Only in fast or simultaneous open. If a fast open socket is
591 * already accepted it is treated as a connected one below.
592 */
593 if (fastopen && !fastopen->sk)
594 break;
595
596 ip_icmp_error(sk, skb, err, th->dest, info, (u8 *)th);
597
598 if (!sock_owned_by_user(sk)) {
599 sk->sk_err = err;
600
601 sk_error_report(sk);
602
603 tcp_done(sk);
604 } else {
605 sk->sk_err_soft = err;
606 }
607 goto out;
608 }
609
610 /* If we've already connected we will keep trying
611 * until we time out, or the user gives up.
612 *
613 * rfc1122 4.2.3.9 allows to consider as hard errors
614 * only PROTO_UNREACH and PORT_UNREACH (well, FRAG_FAILED too,
615 * but it is obsoleted by pmtu discovery).
616 *
617 * Note, that in modern internet, where routing is unreliable
618 * and in each dark corner broken firewalls sit, sending random
619 * errors ordered by their masters even this two messages finally lose
620 * their original sense (even Linux sends invalid PORT_UNREACHs)
621 *
622 * Now we are in compliance with RFCs.
623 * --ANK (980905)
624 */
625
626 inet = inet_sk(sk);
627 if (!sock_owned_by_user(sk) && inet->recverr) {
628 sk->sk_err = err;
629 sk_error_report(sk);
630 } else { /* Only an error on timeout */
631 sk->sk_err_soft = err;
632 }
633
634out:
635 bh_unlock_sock(sk);
636 sock_put(sk);
637 return 0;
638}
639
640void __tcp_v4_send_check(struct sk_buff *skb, __be32 saddr, __be32 daddr)
641{
642 struct tcphdr *th = tcp_hdr(skb);
643
644 th->check = ~tcp_v4_check(skb->len, saddr, daddr, 0);
645 skb->csum_start = skb_transport_header(skb) - skb->head;
646 skb->csum_offset = offsetof(struct tcphdr, check);
647}
648
649/* This routine computes an IPv4 TCP checksum. */
650void tcp_v4_send_check(struct sock *sk, struct sk_buff *skb)
651{
652 const struct inet_sock *inet = inet_sk(sk);
653
654 __tcp_v4_send_check(skb, inet->inet_saddr, inet->inet_daddr);
655}
656EXPORT_SYMBOL(tcp_v4_send_check);
657
658/*
659 * This routine will send an RST to the other tcp.
660 *
661 * Someone asks: why I NEVER use socket parameters (TOS, TTL etc.)
662 * for reset.
663 * Answer: if a packet caused RST, it is not for a socket
664 * existing in our system, if it is matched to a socket,
665 * it is just duplicate segment or bug in other side's TCP.
666 * So that we build reply only basing on parameters
667 * arrived with segment.
668 * Exception: precedence violation. We do not implement it in any case.
669 */
670
671#ifdef CONFIG_TCP_MD5SIG
672#define OPTION_BYTES TCPOLEN_MD5SIG_ALIGNED
673#else
674#define OPTION_BYTES sizeof(__be32)
675#endif
676
677static void tcp_v4_send_reset(const struct sock *sk, struct sk_buff *skb)
678{
679 const struct tcphdr *th = tcp_hdr(skb);
680 struct {
681 struct tcphdr th;
682 __be32 opt[OPTION_BYTES / sizeof(__be32)];
683 } rep;
684 struct ip_reply_arg arg;
685#ifdef CONFIG_TCP_MD5SIG
686 struct tcp_md5sig_key *key = NULL;
687 const __u8 *hash_location = NULL;
688 unsigned char newhash[16];
689 int genhash;
690 struct sock *sk1 = NULL;
691#endif
692 u64 transmit_time = 0;
693 struct sock *ctl_sk;
694 struct net *net;
695
696 /* Never send a reset in response to a reset. */
697 if (th->rst)
698 return;
699
700 /* If sk not NULL, it means we did a successful lookup and incoming
701 * route had to be correct. prequeue might have dropped our dst.
702 */
703 if (!sk && skb_rtable(skb)->rt_type != RTN_LOCAL)
704 return;
705
706 /* Swap the send and the receive. */
707 memset(&rep, 0, sizeof(rep));
708 rep.th.dest = th->source;
709 rep.th.source = th->dest;
710 rep.th.doff = sizeof(struct tcphdr) / 4;
711 rep.th.rst = 1;
712
713 if (th->ack) {
714 rep.th.seq = th->ack_seq;
715 } else {
716 rep.th.ack = 1;
717 rep.th.ack_seq = htonl(ntohl(th->seq) + th->syn + th->fin +
718 skb->len - (th->doff << 2));
719 }
720
721 memset(&arg, 0, sizeof(arg));
722 arg.iov[0].iov_base = (unsigned char *)&rep;
723 arg.iov[0].iov_len = sizeof(rep.th);
724
725 net = sk ? sock_net(sk) : dev_net(skb_dst(skb)->dev);
726#ifdef CONFIG_TCP_MD5SIG
727 rcu_read_lock();
728 hash_location = tcp_parse_md5sig_option(th);
729 if (sk && sk_fullsock(sk)) {
730 const union tcp_md5_addr *addr;
731 int l3index;
732
733 /* sdif set, means packet ingressed via a device
734 * in an L3 domain and inet_iif is set to it.
735 */
736 l3index = tcp_v4_sdif(skb) ? inet_iif(skb) : 0;
737 addr = (union tcp_md5_addr *)&ip_hdr(skb)->saddr;
738 key = tcp_md5_do_lookup(sk, l3index, addr, AF_INET);
739 } else if (hash_location) {
740 const union tcp_md5_addr *addr;
741 int sdif = tcp_v4_sdif(skb);
742 int dif = inet_iif(skb);
743 int l3index;
744
745 /*
746 * active side is lost. Try to find listening socket through
747 * source port, and then find md5 key through listening socket.
748 * we are not loose security here:
749 * Incoming packet is checked with md5 hash with finding key,
750 * no RST generated if md5 hash doesn't match.
751 */
752 sk1 = __inet_lookup_listener(net, net->ipv4.tcp_death_row.hashinfo,
753 NULL, 0, ip_hdr(skb)->saddr,
754 th->source, ip_hdr(skb)->daddr,
755 ntohs(th->source), dif, sdif);
756 /* don't send rst if it can't find key */
757 if (!sk1)
758 goto out;
759
760 /* sdif set, means packet ingressed via a device
761 * in an L3 domain and dif is set to it.
762 */
763 l3index = sdif ? dif : 0;
764 addr = (union tcp_md5_addr *)&ip_hdr(skb)->saddr;
765 key = tcp_md5_do_lookup(sk1, l3index, addr, AF_INET);
766 if (!key)
767 goto out;
768
769
770 genhash = tcp_v4_md5_hash_skb(newhash, key, NULL, skb);
771 if (genhash || memcmp(hash_location, newhash, 16) != 0)
772 goto out;
773
774 }
775
776 if (key) {
777 rep.opt[0] = htonl((TCPOPT_NOP << 24) |
778 (TCPOPT_NOP << 16) |
779 (TCPOPT_MD5SIG << 8) |
780 TCPOLEN_MD5SIG);
781 /* Update length and the length the header thinks exists */
782 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED;
783 rep.th.doff = arg.iov[0].iov_len / 4;
784
785 tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[1],
786 key, ip_hdr(skb)->saddr,
787 ip_hdr(skb)->daddr, &rep.th);
788 }
789#endif
790 /* Can't co-exist with TCPMD5, hence check rep.opt[0] */
791 if (rep.opt[0] == 0) {
792 __be32 mrst = mptcp_reset_option(skb);
793
794 if (mrst) {
795 rep.opt[0] = mrst;
796 arg.iov[0].iov_len += sizeof(mrst);
797 rep.th.doff = arg.iov[0].iov_len / 4;
798 }
799 }
800
801 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
802 ip_hdr(skb)->saddr, /* XXX */
803 arg.iov[0].iov_len, IPPROTO_TCP, 0);
804 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
805 arg.flags = (sk && inet_sk_transparent(sk)) ? IP_REPLY_ARG_NOSRCCHECK : 0;
806
807 /* When socket is gone, all binding information is lost.
808 * routing might fail in this case. No choice here, if we choose to force
809 * input interface, we will misroute in case of asymmetric route.
810 */
811 if (sk) {
812 arg.bound_dev_if = sk->sk_bound_dev_if;
813 if (sk_fullsock(sk))
814 trace_tcp_send_reset(sk, skb);
815 }
816
817 BUILD_BUG_ON(offsetof(struct sock, sk_bound_dev_if) !=
818 offsetof(struct inet_timewait_sock, tw_bound_dev_if));
819
820 arg.tos = ip_hdr(skb)->tos;
821 arg.uid = sock_net_uid(net, sk && sk_fullsock(sk) ? sk : NULL);
822 local_bh_disable();
823 ctl_sk = this_cpu_read(ipv4_tcp_sk);
824 sock_net_set(ctl_sk, net);
825 if (sk) {
826 ctl_sk->sk_mark = (sk->sk_state == TCP_TIME_WAIT) ?
827 inet_twsk(sk)->tw_mark : sk->sk_mark;
828 ctl_sk->sk_priority = (sk->sk_state == TCP_TIME_WAIT) ?
829 inet_twsk(sk)->tw_priority : sk->sk_priority;
830 transmit_time = tcp_transmit_time(sk);
831 xfrm_sk_clone_policy(ctl_sk, sk);
832 }
833 ip_send_unicast_reply(ctl_sk,
834 skb, &TCP_SKB_CB(skb)->header.h4.opt,
835 ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
836 &arg, arg.iov[0].iov_len,
837 transmit_time);
838
839 ctl_sk->sk_mark = 0;
840 xfrm_sk_free_policy(ctl_sk);
841 sock_net_set(ctl_sk, &init_net);
842 __TCP_INC_STATS(net, TCP_MIB_OUTSEGS);
843 __TCP_INC_STATS(net, TCP_MIB_OUTRSTS);
844 local_bh_enable();
845
846#ifdef CONFIG_TCP_MD5SIG
847out:
848 rcu_read_unlock();
849#endif
850}
851
852/* The code following below sending ACKs in SYN-RECV and TIME-WAIT states
853 outside socket context is ugly, certainly. What can I do?
854 */
855
856static void tcp_v4_send_ack(const struct sock *sk,
857 struct sk_buff *skb, u32 seq, u32 ack,
858 u32 win, u32 tsval, u32 tsecr, int oif,
859 struct tcp_md5sig_key *key,
860 int reply_flags, u8 tos)
861{
862 const struct tcphdr *th = tcp_hdr(skb);
863 struct {
864 struct tcphdr th;
865 __be32 opt[(TCPOLEN_TSTAMP_ALIGNED >> 2)
866#ifdef CONFIG_TCP_MD5SIG
867 + (TCPOLEN_MD5SIG_ALIGNED >> 2)
868#endif
869 ];
870 } rep;
871 struct net *net = sock_net(sk);
872 struct ip_reply_arg arg;
873 struct sock *ctl_sk;
874 u64 transmit_time;
875
876 memset(&rep.th, 0, sizeof(struct tcphdr));
877 memset(&arg, 0, sizeof(arg));
878
879 arg.iov[0].iov_base = (unsigned char *)&rep;
880 arg.iov[0].iov_len = sizeof(rep.th);
881 if (tsecr) {
882 rep.opt[0] = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
883 (TCPOPT_TIMESTAMP << 8) |
884 TCPOLEN_TIMESTAMP);
885 rep.opt[1] = htonl(tsval);
886 rep.opt[2] = htonl(tsecr);
887 arg.iov[0].iov_len += TCPOLEN_TSTAMP_ALIGNED;
888 }
889
890 /* Swap the send and the receive. */
891 rep.th.dest = th->source;
892 rep.th.source = th->dest;
893 rep.th.doff = arg.iov[0].iov_len / 4;
894 rep.th.seq = htonl(seq);
895 rep.th.ack_seq = htonl(ack);
896 rep.th.ack = 1;
897 rep.th.window = htons(win);
898
899#ifdef CONFIG_TCP_MD5SIG
900 if (key) {
901 int offset = (tsecr) ? 3 : 0;
902
903 rep.opt[offset++] = htonl((TCPOPT_NOP << 24) |
904 (TCPOPT_NOP << 16) |
905 (TCPOPT_MD5SIG << 8) |
906 TCPOLEN_MD5SIG);
907 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED;
908 rep.th.doff = arg.iov[0].iov_len/4;
909
910 tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[offset],
911 key, ip_hdr(skb)->saddr,
912 ip_hdr(skb)->daddr, &rep.th);
913 }
914#endif
915 arg.flags = reply_flags;
916 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
917 ip_hdr(skb)->saddr, /* XXX */
918 arg.iov[0].iov_len, IPPROTO_TCP, 0);
919 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
920 if (oif)
921 arg.bound_dev_if = oif;
922 arg.tos = tos;
923 arg.uid = sock_net_uid(net, sk_fullsock(sk) ? sk : NULL);
924 local_bh_disable();
925 ctl_sk = this_cpu_read(ipv4_tcp_sk);
926 sock_net_set(ctl_sk, net);
927 ctl_sk->sk_mark = (sk->sk_state == TCP_TIME_WAIT) ?
928 inet_twsk(sk)->tw_mark : sk->sk_mark;
929 ctl_sk->sk_priority = (sk->sk_state == TCP_TIME_WAIT) ?
930 inet_twsk(sk)->tw_priority : sk->sk_priority;
931 transmit_time = tcp_transmit_time(sk);
932 ip_send_unicast_reply(ctl_sk,
933 skb, &TCP_SKB_CB(skb)->header.h4.opt,
934 ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
935 &arg, arg.iov[0].iov_len,
936 transmit_time);
937
938 ctl_sk->sk_mark = 0;
939 sock_net_set(ctl_sk, &init_net);
940 __TCP_INC_STATS(net, TCP_MIB_OUTSEGS);
941 local_bh_enable();
942}
943
944static void tcp_v4_timewait_ack(struct sock *sk, struct sk_buff *skb)
945{
946 struct inet_timewait_sock *tw = inet_twsk(sk);
947 struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
948
949 tcp_v4_send_ack(sk, skb,
950 tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
951 tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
952 tcp_time_stamp_raw() + tcptw->tw_ts_offset,
953 tcptw->tw_ts_recent,
954 tw->tw_bound_dev_if,
955 tcp_twsk_md5_key(tcptw),
956 tw->tw_transparent ? IP_REPLY_ARG_NOSRCCHECK : 0,
957 tw->tw_tos
958 );
959
960 inet_twsk_put(tw);
961}
962
963static void tcp_v4_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb,
964 struct request_sock *req)
965{
966 const union tcp_md5_addr *addr;
967 int l3index;
968
969 /* sk->sk_state == TCP_LISTEN -> for regular TCP_SYN_RECV
970 * sk->sk_state == TCP_SYN_RECV -> for Fast Open.
971 */
972 u32 seq = (sk->sk_state == TCP_LISTEN) ? tcp_rsk(req)->snt_isn + 1 :
973 tcp_sk(sk)->snd_nxt;
974
975 /* RFC 7323 2.3
976 * The window field (SEG.WND) of every outgoing segment, with the
977 * exception of <SYN> segments, MUST be right-shifted by
978 * Rcv.Wind.Shift bits:
979 */
980 addr = (union tcp_md5_addr *)&ip_hdr(skb)->saddr;
981 l3index = tcp_v4_sdif(skb) ? inet_iif(skb) : 0;
982 tcp_v4_send_ack(sk, skb, seq,
983 tcp_rsk(req)->rcv_nxt,
984 req->rsk_rcv_wnd >> inet_rsk(req)->rcv_wscale,
985 tcp_time_stamp_raw() + tcp_rsk(req)->ts_off,
986 req->ts_recent,
987 0,
988 tcp_md5_do_lookup(sk, l3index, addr, AF_INET),
989 inet_rsk(req)->no_srccheck ? IP_REPLY_ARG_NOSRCCHECK : 0,
990 ip_hdr(skb)->tos);
991}
992
993/*
994 * Send a SYN-ACK after having received a SYN.
995 * This still operates on a request_sock only, not on a big
996 * socket.
997 */
998static int tcp_v4_send_synack(const struct sock *sk, struct dst_entry *dst,
999 struct flowi *fl,
1000 struct request_sock *req,
1001 struct tcp_fastopen_cookie *foc,
1002 enum tcp_synack_type synack_type,
1003 struct sk_buff *syn_skb)
1004{
1005 const struct inet_request_sock *ireq = inet_rsk(req);
1006 struct flowi4 fl4;
1007 int err = -1;
1008 struct sk_buff *skb;
1009 u8 tos;
1010
1011 /* First, grab a route. */
1012 if (!dst && (dst = inet_csk_route_req(sk, &fl4, req)) == NULL)
1013 return -1;
1014
1015 skb = tcp_make_synack(sk, dst, req, foc, synack_type, syn_skb);
1016
1017 if (skb) {
1018 __tcp_v4_send_check(skb, ireq->ir_loc_addr, ireq->ir_rmt_addr);
1019
1020 tos = READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_reflect_tos) ?
1021 (tcp_rsk(req)->syn_tos & ~INET_ECN_MASK) |
1022 (inet_sk(sk)->tos & INET_ECN_MASK) :
1023 inet_sk(sk)->tos;
1024
1025 if (!INET_ECN_is_capable(tos) &&
1026 tcp_bpf_ca_needs_ecn((struct sock *)req))
1027 tos |= INET_ECN_ECT_0;
1028
1029 rcu_read_lock();
1030 err = ip_build_and_send_pkt(skb, sk, ireq->ir_loc_addr,
1031 ireq->ir_rmt_addr,
1032 rcu_dereference(ireq->ireq_opt),
1033 tos);
1034 rcu_read_unlock();
1035 err = net_xmit_eval(err);
1036 }
1037
1038 return err;
1039}
1040
1041/*
1042 * IPv4 request_sock destructor.
1043 */
1044static void tcp_v4_reqsk_destructor(struct request_sock *req)
1045{
1046 kfree(rcu_dereference_protected(inet_rsk(req)->ireq_opt, 1));
1047}
1048
1049#ifdef CONFIG_TCP_MD5SIG
1050/*
1051 * RFC2385 MD5 checksumming requires a mapping of
1052 * IP address->MD5 Key.
1053 * We need to maintain these in the sk structure.
1054 */
1055
1056DEFINE_STATIC_KEY_DEFERRED_FALSE(tcp_md5_needed, HZ);
1057EXPORT_SYMBOL(tcp_md5_needed);
1058
1059static bool better_md5_match(struct tcp_md5sig_key *old, struct tcp_md5sig_key *new)
1060{
1061 if (!old)
1062 return true;
1063
1064 /* l3index always overrides non-l3index */
1065 if (old->l3index && new->l3index == 0)
1066 return false;
1067 if (old->l3index == 0 && new->l3index)
1068 return true;
1069
1070 return old->prefixlen < new->prefixlen;
1071}
1072
1073/* Find the Key structure for an address. */
1074struct tcp_md5sig_key *__tcp_md5_do_lookup(const struct sock *sk, int l3index,
1075 const union tcp_md5_addr *addr,
1076 int family)
1077{
1078 const struct tcp_sock *tp = tcp_sk(sk);
1079 struct tcp_md5sig_key *key;
1080 const struct tcp_md5sig_info *md5sig;
1081 __be32 mask;
1082 struct tcp_md5sig_key *best_match = NULL;
1083 bool match;
1084
1085 /* caller either holds rcu_read_lock() or socket lock */
1086 md5sig = rcu_dereference_check(tp->md5sig_info,
1087 lockdep_sock_is_held(sk));
1088 if (!md5sig)
1089 return NULL;
1090
1091 hlist_for_each_entry_rcu(key, &md5sig->head, node,
1092 lockdep_sock_is_held(sk)) {
1093 if (key->family != family)
1094 continue;
1095 if (key->flags & TCP_MD5SIG_FLAG_IFINDEX && key->l3index != l3index)
1096 continue;
1097 if (family == AF_INET) {
1098 mask = inet_make_mask(key->prefixlen);
1099 match = (key->addr.a4.s_addr & mask) ==
1100 (addr->a4.s_addr & mask);
1101#if IS_ENABLED(CONFIG_IPV6)
1102 } else if (family == AF_INET6) {
1103 match = ipv6_prefix_equal(&key->addr.a6, &addr->a6,
1104 key->prefixlen);
1105#endif
1106 } else {
1107 match = false;
1108 }
1109
1110 if (match && better_md5_match(best_match, key))
1111 best_match = key;
1112 }
1113 return best_match;
1114}
1115EXPORT_SYMBOL(__tcp_md5_do_lookup);
1116
1117static struct tcp_md5sig_key *tcp_md5_do_lookup_exact(const struct sock *sk,
1118 const union tcp_md5_addr *addr,
1119 int family, u8 prefixlen,
1120 int l3index, u8 flags)
1121{
1122 const struct tcp_sock *tp = tcp_sk(sk);
1123 struct tcp_md5sig_key *key;
1124 unsigned int size = sizeof(struct in_addr);
1125 const struct tcp_md5sig_info *md5sig;
1126
1127 /* caller either holds rcu_read_lock() or socket lock */
1128 md5sig = rcu_dereference_check(tp->md5sig_info,
1129 lockdep_sock_is_held(sk));
1130 if (!md5sig)
1131 return NULL;
1132#if IS_ENABLED(CONFIG_IPV6)
1133 if (family == AF_INET6)
1134 size = sizeof(struct in6_addr);
1135#endif
1136 hlist_for_each_entry_rcu(key, &md5sig->head, node,
1137 lockdep_sock_is_held(sk)) {
1138 if (key->family != family)
1139 continue;
1140 if ((key->flags & TCP_MD5SIG_FLAG_IFINDEX) != (flags & TCP_MD5SIG_FLAG_IFINDEX))
1141 continue;
1142 if (key->l3index != l3index)
1143 continue;
1144 if (!memcmp(&key->addr, addr, size) &&
1145 key->prefixlen == prefixlen)
1146 return key;
1147 }
1148 return NULL;
1149}
1150
1151struct tcp_md5sig_key *tcp_v4_md5_lookup(const struct sock *sk,
1152 const struct sock *addr_sk)
1153{
1154 const union tcp_md5_addr *addr;
1155 int l3index;
1156
1157 l3index = l3mdev_master_ifindex_by_index(sock_net(sk),
1158 addr_sk->sk_bound_dev_if);
1159 addr = (const union tcp_md5_addr *)&addr_sk->sk_daddr;
1160 return tcp_md5_do_lookup(sk, l3index, addr, AF_INET);
1161}
1162EXPORT_SYMBOL(tcp_v4_md5_lookup);
1163
1164static int tcp_md5sig_info_add(struct sock *sk, gfp_t gfp)
1165{
1166 struct tcp_sock *tp = tcp_sk(sk);
1167 struct tcp_md5sig_info *md5sig;
1168
1169 md5sig = kmalloc(sizeof(*md5sig), gfp);
1170 if (!md5sig)
1171 return -ENOMEM;
1172
1173 sk_gso_disable(sk);
1174 INIT_HLIST_HEAD(&md5sig->head);
1175 rcu_assign_pointer(tp->md5sig_info, md5sig);
1176 return 0;
1177}
1178
1179/* This can be called on a newly created socket, from other files */
1180static int __tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr,
1181 int family, u8 prefixlen, int l3index, u8 flags,
1182 const u8 *newkey, u8 newkeylen, gfp_t gfp)
1183{
1184 /* Add Key to the list */
1185 struct tcp_md5sig_key *key;
1186 struct tcp_sock *tp = tcp_sk(sk);
1187 struct tcp_md5sig_info *md5sig;
1188
1189 key = tcp_md5_do_lookup_exact(sk, addr, family, prefixlen, l3index, flags);
1190 if (key) {
1191 /* Pre-existing entry - just update that one.
1192 * Note that the key might be used concurrently.
1193 * data_race() is telling kcsan that we do not care of
1194 * key mismatches, since changing MD5 key on live flows
1195 * can lead to packet drops.
1196 */
1197 data_race(memcpy(key->key, newkey, newkeylen));
1198
1199 /* Pairs with READ_ONCE() in tcp_md5_hash_key().
1200 * Also note that a reader could catch new key->keylen value
1201 * but old key->key[], this is the reason we use __GFP_ZERO
1202 * at sock_kmalloc() time below these lines.
1203 */
1204 WRITE_ONCE(key->keylen, newkeylen);
1205
1206 return 0;
1207 }
1208
1209 md5sig = rcu_dereference_protected(tp->md5sig_info,
1210 lockdep_sock_is_held(sk));
1211
1212 key = sock_kmalloc(sk, sizeof(*key), gfp | __GFP_ZERO);
1213 if (!key)
1214 return -ENOMEM;
1215 if (!tcp_alloc_md5sig_pool()) {
1216 sock_kfree_s(sk, key, sizeof(*key));
1217 return -ENOMEM;
1218 }
1219
1220 memcpy(key->key, newkey, newkeylen);
1221 key->keylen = newkeylen;
1222 key->family = family;
1223 key->prefixlen = prefixlen;
1224 key->l3index = l3index;
1225 key->flags = flags;
1226 memcpy(&key->addr, addr,
1227 (IS_ENABLED(CONFIG_IPV6) && family == AF_INET6) ? sizeof(struct in6_addr) :
1228 sizeof(struct in_addr));
1229 hlist_add_head_rcu(&key->node, &md5sig->head);
1230 return 0;
1231}
1232
1233int tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr,
1234 int family, u8 prefixlen, int l3index, u8 flags,
1235 const u8 *newkey, u8 newkeylen)
1236{
1237 struct tcp_sock *tp = tcp_sk(sk);
1238
1239 if (!rcu_dereference_protected(tp->md5sig_info, lockdep_sock_is_held(sk))) {
1240 if (tcp_md5sig_info_add(sk, GFP_KERNEL))
1241 return -ENOMEM;
1242
1243 if (!static_branch_inc(&tcp_md5_needed.key)) {
1244 struct tcp_md5sig_info *md5sig;
1245
1246 md5sig = rcu_dereference_protected(tp->md5sig_info, lockdep_sock_is_held(sk));
1247 rcu_assign_pointer(tp->md5sig_info, NULL);
1248 kfree_rcu(md5sig, rcu);
1249 return -EUSERS;
1250 }
1251 }
1252
1253 return __tcp_md5_do_add(sk, addr, family, prefixlen, l3index, flags,
1254 newkey, newkeylen, GFP_KERNEL);
1255}
1256EXPORT_SYMBOL(tcp_md5_do_add);
1257
1258int tcp_md5_key_copy(struct sock *sk, const union tcp_md5_addr *addr,
1259 int family, u8 prefixlen, int l3index,
1260 struct tcp_md5sig_key *key)
1261{
1262 struct tcp_sock *tp = tcp_sk(sk);
1263
1264 if (!rcu_dereference_protected(tp->md5sig_info, lockdep_sock_is_held(sk))) {
1265 if (tcp_md5sig_info_add(sk, sk_gfp_mask(sk, GFP_ATOMIC)))
1266 return -ENOMEM;
1267
1268 if (!static_key_fast_inc_not_disabled(&tcp_md5_needed.key.key)) {
1269 struct tcp_md5sig_info *md5sig;
1270
1271 md5sig = rcu_dereference_protected(tp->md5sig_info, lockdep_sock_is_held(sk));
1272 net_warn_ratelimited("Too many TCP-MD5 keys in the system\n");
1273 rcu_assign_pointer(tp->md5sig_info, NULL);
1274 kfree_rcu(md5sig, rcu);
1275 return -EUSERS;
1276 }
1277 }
1278
1279 return __tcp_md5_do_add(sk, addr, family, prefixlen, l3index,
1280 key->flags, key->key, key->keylen,
1281 sk_gfp_mask(sk, GFP_ATOMIC));
1282}
1283EXPORT_SYMBOL(tcp_md5_key_copy);
1284
1285int tcp_md5_do_del(struct sock *sk, const union tcp_md5_addr *addr, int family,
1286 u8 prefixlen, int l3index, u8 flags)
1287{
1288 struct tcp_md5sig_key *key;
1289
1290 key = tcp_md5_do_lookup_exact(sk, addr, family, prefixlen, l3index, flags);
1291 if (!key)
1292 return -ENOENT;
1293 hlist_del_rcu(&key->node);
1294 atomic_sub(sizeof(*key), &sk->sk_omem_alloc);
1295 kfree_rcu(key, rcu);
1296 return 0;
1297}
1298EXPORT_SYMBOL(tcp_md5_do_del);
1299
1300static void tcp_clear_md5_list(struct sock *sk)
1301{
1302 struct tcp_sock *tp = tcp_sk(sk);
1303 struct tcp_md5sig_key *key;
1304 struct hlist_node *n;
1305 struct tcp_md5sig_info *md5sig;
1306
1307 md5sig = rcu_dereference_protected(tp->md5sig_info, 1);
1308
1309 hlist_for_each_entry_safe(key, n, &md5sig->head, node) {
1310 hlist_del_rcu(&key->node);
1311 atomic_sub(sizeof(*key), &sk->sk_omem_alloc);
1312 kfree_rcu(key, rcu);
1313 }
1314}
1315
1316static int tcp_v4_parse_md5_keys(struct sock *sk, int optname,
1317 sockptr_t optval, int optlen)
1318{
1319 struct tcp_md5sig cmd;
1320 struct sockaddr_in *sin = (struct sockaddr_in *)&cmd.tcpm_addr;
1321 const union tcp_md5_addr *addr;
1322 u8 prefixlen = 32;
1323 int l3index = 0;
1324 u8 flags;
1325
1326 if (optlen < sizeof(cmd))
1327 return -EINVAL;
1328
1329 if (copy_from_sockptr(&cmd, optval, sizeof(cmd)))
1330 return -EFAULT;
1331
1332 if (sin->sin_family != AF_INET)
1333 return -EINVAL;
1334
1335 flags = cmd.tcpm_flags & TCP_MD5SIG_FLAG_IFINDEX;
1336
1337 if (optname == TCP_MD5SIG_EXT &&
1338 cmd.tcpm_flags & TCP_MD5SIG_FLAG_PREFIX) {
1339 prefixlen = cmd.tcpm_prefixlen;
1340 if (prefixlen > 32)
1341 return -EINVAL;
1342 }
1343
1344 if (optname == TCP_MD5SIG_EXT && cmd.tcpm_ifindex &&
1345 cmd.tcpm_flags & TCP_MD5SIG_FLAG_IFINDEX) {
1346 struct net_device *dev;
1347
1348 rcu_read_lock();
1349 dev = dev_get_by_index_rcu(sock_net(sk), cmd.tcpm_ifindex);
1350 if (dev && netif_is_l3_master(dev))
1351 l3index = dev->ifindex;
1352
1353 rcu_read_unlock();
1354
1355 /* ok to reference set/not set outside of rcu;
1356 * right now device MUST be an L3 master
1357 */
1358 if (!dev || !l3index)
1359 return -EINVAL;
1360 }
1361
1362 addr = (union tcp_md5_addr *)&sin->sin_addr.s_addr;
1363
1364 if (!cmd.tcpm_keylen)
1365 return tcp_md5_do_del(sk, addr, AF_INET, prefixlen, l3index, flags);
1366
1367 if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN)
1368 return -EINVAL;
1369
1370 return tcp_md5_do_add(sk, addr, AF_INET, prefixlen, l3index, flags,
1371 cmd.tcpm_key, cmd.tcpm_keylen);
1372}
1373
1374static int tcp_v4_md5_hash_headers(struct tcp_md5sig_pool *hp,
1375 __be32 daddr, __be32 saddr,
1376 const struct tcphdr *th, int nbytes)
1377{
1378 struct tcp4_pseudohdr *bp;
1379 struct scatterlist sg;
1380 struct tcphdr *_th;
1381
1382 bp = hp->scratch;
1383 bp->saddr = saddr;
1384 bp->daddr = daddr;
1385 bp->pad = 0;
1386 bp->protocol = IPPROTO_TCP;
1387 bp->len = cpu_to_be16(nbytes);
1388
1389 _th = (struct tcphdr *)(bp + 1);
1390 memcpy(_th, th, sizeof(*th));
1391 _th->check = 0;
1392
1393 sg_init_one(&sg, bp, sizeof(*bp) + sizeof(*th));
1394 ahash_request_set_crypt(hp->md5_req, &sg, NULL,
1395 sizeof(*bp) + sizeof(*th));
1396 return crypto_ahash_update(hp->md5_req);
1397}
1398
1399static int tcp_v4_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key,
1400 __be32 daddr, __be32 saddr, const struct tcphdr *th)
1401{
1402 struct tcp_md5sig_pool *hp;
1403 struct ahash_request *req;
1404
1405 hp = tcp_get_md5sig_pool();
1406 if (!hp)
1407 goto clear_hash_noput;
1408 req = hp->md5_req;
1409
1410 if (crypto_ahash_init(req))
1411 goto clear_hash;
1412 if (tcp_v4_md5_hash_headers(hp, daddr, saddr, th, th->doff << 2))
1413 goto clear_hash;
1414 if (tcp_md5_hash_key(hp, key))
1415 goto clear_hash;
1416 ahash_request_set_crypt(req, NULL, md5_hash, 0);
1417 if (crypto_ahash_final(req))
1418 goto clear_hash;
1419
1420 tcp_put_md5sig_pool();
1421 return 0;
1422
1423clear_hash:
1424 tcp_put_md5sig_pool();
1425clear_hash_noput:
1426 memset(md5_hash, 0, 16);
1427 return 1;
1428}
1429
1430int tcp_v4_md5_hash_skb(char *md5_hash, const struct tcp_md5sig_key *key,
1431 const struct sock *sk,
1432 const struct sk_buff *skb)
1433{
1434 struct tcp_md5sig_pool *hp;
1435 struct ahash_request *req;
1436 const struct tcphdr *th = tcp_hdr(skb);
1437 __be32 saddr, daddr;
1438
1439 if (sk) { /* valid for establish/request sockets */
1440 saddr = sk->sk_rcv_saddr;
1441 daddr = sk->sk_daddr;
1442 } else {
1443 const struct iphdr *iph = ip_hdr(skb);
1444 saddr = iph->saddr;
1445 daddr = iph->daddr;
1446 }
1447
1448 hp = tcp_get_md5sig_pool();
1449 if (!hp)
1450 goto clear_hash_noput;
1451 req = hp->md5_req;
1452
1453 if (crypto_ahash_init(req))
1454 goto clear_hash;
1455
1456 if (tcp_v4_md5_hash_headers(hp, daddr, saddr, th, skb->len))
1457 goto clear_hash;
1458 if (tcp_md5_hash_skb_data(hp, skb, th->doff << 2))
1459 goto clear_hash;
1460 if (tcp_md5_hash_key(hp, key))
1461 goto clear_hash;
1462 ahash_request_set_crypt(req, NULL, md5_hash, 0);
1463 if (crypto_ahash_final(req))
1464 goto clear_hash;
1465
1466 tcp_put_md5sig_pool();
1467 return 0;
1468
1469clear_hash:
1470 tcp_put_md5sig_pool();
1471clear_hash_noput:
1472 memset(md5_hash, 0, 16);
1473 return 1;
1474}
1475EXPORT_SYMBOL(tcp_v4_md5_hash_skb);
1476
1477#endif
1478
1479static void tcp_v4_init_req(struct request_sock *req,
1480 const struct sock *sk_listener,
1481 struct sk_buff *skb)
1482{
1483 struct inet_request_sock *ireq = inet_rsk(req);
1484 struct net *net = sock_net(sk_listener);
1485
1486 sk_rcv_saddr_set(req_to_sk(req), ip_hdr(skb)->daddr);
1487 sk_daddr_set(req_to_sk(req), ip_hdr(skb)->saddr);
1488 RCU_INIT_POINTER(ireq->ireq_opt, tcp_v4_save_options(net, skb));
1489}
1490
1491static struct dst_entry *tcp_v4_route_req(const struct sock *sk,
1492 struct sk_buff *skb,
1493 struct flowi *fl,
1494 struct request_sock *req)
1495{
1496 tcp_v4_init_req(req, sk, skb);
1497
1498 if (security_inet_conn_request(sk, skb, req))
1499 return NULL;
1500
1501 return inet_csk_route_req(sk, &fl->u.ip4, req);
1502}
1503
1504struct request_sock_ops tcp_request_sock_ops __read_mostly = {
1505 .family = PF_INET,
1506 .obj_size = sizeof(struct tcp_request_sock),
1507 .rtx_syn_ack = tcp_rtx_synack,
1508 .send_ack = tcp_v4_reqsk_send_ack,
1509 .destructor = tcp_v4_reqsk_destructor,
1510 .send_reset = tcp_v4_send_reset,
1511 .syn_ack_timeout = tcp_syn_ack_timeout,
1512};
1513
1514const struct tcp_request_sock_ops tcp_request_sock_ipv4_ops = {
1515 .mss_clamp = TCP_MSS_DEFAULT,
1516#ifdef CONFIG_TCP_MD5SIG
1517 .req_md5_lookup = tcp_v4_md5_lookup,
1518 .calc_md5_hash = tcp_v4_md5_hash_skb,
1519#endif
1520#ifdef CONFIG_SYN_COOKIES
1521 .cookie_init_seq = cookie_v4_init_sequence,
1522#endif
1523 .route_req = tcp_v4_route_req,
1524 .init_seq = tcp_v4_init_seq,
1525 .init_ts_off = tcp_v4_init_ts_off,
1526 .send_synack = tcp_v4_send_synack,
1527};
1528
1529int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
1530{
1531 /* Never answer to SYNs send to broadcast or multicast */
1532 if (skb_rtable(skb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
1533 goto drop;
1534
1535 return tcp_conn_request(&tcp_request_sock_ops,
1536 &tcp_request_sock_ipv4_ops, sk, skb);
1537
1538drop:
1539 tcp_listendrop(sk);
1540 return 0;
1541}
1542EXPORT_SYMBOL(tcp_v4_conn_request);
1543
1544
1545/*
1546 * The three way handshake has completed - we got a valid synack -
1547 * now create the new socket.
1548 */
1549struct sock *tcp_v4_syn_recv_sock(const struct sock *sk, struct sk_buff *skb,
1550 struct request_sock *req,
1551 struct dst_entry *dst,
1552 struct request_sock *req_unhash,
1553 bool *own_req)
1554{
1555 struct inet_request_sock *ireq;
1556 bool found_dup_sk = false;
1557 struct inet_sock *newinet;
1558 struct tcp_sock *newtp;
1559 struct sock *newsk;
1560#ifdef CONFIG_TCP_MD5SIG
1561 const union tcp_md5_addr *addr;
1562 struct tcp_md5sig_key *key;
1563 int l3index;
1564#endif
1565 struct ip_options_rcu *inet_opt;
1566
1567 if (sk_acceptq_is_full(sk))
1568 goto exit_overflow;
1569
1570 newsk = tcp_create_openreq_child(sk, req, skb);
1571 if (!newsk)
1572 goto exit_nonewsk;
1573
1574 newsk->sk_gso_type = SKB_GSO_TCPV4;
1575 inet_sk_rx_dst_set(newsk, skb);
1576
1577 newtp = tcp_sk(newsk);
1578 newinet = inet_sk(newsk);
1579 ireq = inet_rsk(req);
1580 sk_daddr_set(newsk, ireq->ir_rmt_addr);
1581 sk_rcv_saddr_set(newsk, ireq->ir_loc_addr);
1582 newsk->sk_bound_dev_if = ireq->ir_iif;
1583 newinet->inet_saddr = ireq->ir_loc_addr;
1584 inet_opt = rcu_dereference(ireq->ireq_opt);
1585 RCU_INIT_POINTER(newinet->inet_opt, inet_opt);
1586 newinet->mc_index = inet_iif(skb);
1587 newinet->mc_ttl = ip_hdr(skb)->ttl;
1588 newinet->rcv_tos = ip_hdr(skb)->tos;
1589 inet_csk(newsk)->icsk_ext_hdr_len = 0;
1590 if (inet_opt)
1591 inet_csk(newsk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
1592 newinet->inet_id = get_random_u16();
1593
1594 /* Set ToS of the new socket based upon the value of incoming SYN.
1595 * ECT bits are set later in tcp_init_transfer().
1596 */
1597 if (READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_reflect_tos))
1598 newinet->tos = tcp_rsk(req)->syn_tos & ~INET_ECN_MASK;
1599
1600 if (!dst) {
1601 dst = inet_csk_route_child_sock(sk, newsk, req);
1602 if (!dst)
1603 goto put_and_exit;
1604 } else {
1605 /* syncookie case : see end of cookie_v4_check() */
1606 }
1607 sk_setup_caps(newsk, dst);
1608
1609 tcp_ca_openreq_child(newsk, dst);
1610
1611 tcp_sync_mss(newsk, dst_mtu(dst));
1612 newtp->advmss = tcp_mss_clamp(tcp_sk(sk), dst_metric_advmss(dst));
1613
1614 tcp_initialize_rcv_mss(newsk);
1615
1616#ifdef CONFIG_TCP_MD5SIG
1617 l3index = l3mdev_master_ifindex_by_index(sock_net(sk), ireq->ir_iif);
1618 /* Copy over the MD5 key from the original socket */
1619 addr = (union tcp_md5_addr *)&newinet->inet_daddr;
1620 key = tcp_md5_do_lookup(sk, l3index, addr, AF_INET);
1621 if (key) {
1622 if (tcp_md5_key_copy(newsk, addr, AF_INET, 32, l3index, key))
1623 goto put_and_exit;
1624 sk_gso_disable(newsk);
1625 }
1626#endif
1627
1628 if (__inet_inherit_port(sk, newsk) < 0)
1629 goto put_and_exit;
1630 *own_req = inet_ehash_nolisten(newsk, req_to_sk(req_unhash),
1631 &found_dup_sk);
1632 if (likely(*own_req)) {
1633 tcp_move_syn(newtp, req);
1634 ireq->ireq_opt = NULL;
1635 } else {
1636 newinet->inet_opt = NULL;
1637
1638 if (!req_unhash && found_dup_sk) {
1639 /* This code path should only be executed in the
1640 * syncookie case only
1641 */
1642 bh_unlock_sock(newsk);
1643 sock_put(newsk);
1644 newsk = NULL;
1645 }
1646 }
1647 return newsk;
1648
1649exit_overflow:
1650 NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
1651exit_nonewsk:
1652 dst_release(dst);
1653exit:
1654 tcp_listendrop(sk);
1655 return NULL;
1656put_and_exit:
1657 newinet->inet_opt = NULL;
1658 inet_csk_prepare_forced_close(newsk);
1659 tcp_done(newsk);
1660 goto exit;
1661}
1662EXPORT_SYMBOL(tcp_v4_syn_recv_sock);
1663
1664static struct sock *tcp_v4_cookie_check(struct sock *sk, struct sk_buff *skb)
1665{
1666#ifdef CONFIG_SYN_COOKIES
1667 const struct tcphdr *th = tcp_hdr(skb);
1668
1669 if (!th->syn)
1670 sk = cookie_v4_check(sk, skb);
1671#endif
1672 return sk;
1673}
1674
1675u16 tcp_v4_get_syncookie(struct sock *sk, struct iphdr *iph,
1676 struct tcphdr *th, u32 *cookie)
1677{
1678 u16 mss = 0;
1679#ifdef CONFIG_SYN_COOKIES
1680 mss = tcp_get_syncookie_mss(&tcp_request_sock_ops,
1681 &tcp_request_sock_ipv4_ops, sk, th);
1682 if (mss) {
1683 *cookie = __cookie_v4_init_sequence(iph, th, &mss);
1684 tcp_synq_overflow(sk);
1685 }
1686#endif
1687 return mss;
1688}
1689
1690INDIRECT_CALLABLE_DECLARE(struct dst_entry *ipv4_dst_check(struct dst_entry *,
1691 u32));
1692/* The socket must have it's spinlock held when we get
1693 * here, unless it is a TCP_LISTEN socket.
1694 *
1695 * We have a potential double-lock case here, so even when
1696 * doing backlog processing we use the BH locking scheme.
1697 * This is because we cannot sleep with the original spinlock
1698 * held.
1699 */
1700int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
1701{
1702 enum skb_drop_reason reason;
1703 struct sock *rsk;
1704
1705 if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
1706 struct dst_entry *dst;
1707
1708 dst = rcu_dereference_protected(sk->sk_rx_dst,
1709 lockdep_sock_is_held(sk));
1710
1711 sock_rps_save_rxhash(sk, skb);
1712 sk_mark_napi_id(sk, skb);
1713 if (dst) {
1714 if (sk->sk_rx_dst_ifindex != skb->skb_iif ||
1715 !INDIRECT_CALL_1(dst->ops->check, ipv4_dst_check,
1716 dst, 0)) {
1717 RCU_INIT_POINTER(sk->sk_rx_dst, NULL);
1718 dst_release(dst);
1719 }
1720 }
1721 tcp_rcv_established(sk, skb);
1722 return 0;
1723 }
1724
1725 reason = SKB_DROP_REASON_NOT_SPECIFIED;
1726 if (tcp_checksum_complete(skb))
1727 goto csum_err;
1728
1729 if (sk->sk_state == TCP_LISTEN) {
1730 struct sock *nsk = tcp_v4_cookie_check(sk, skb);
1731
1732 if (!nsk)
1733 goto discard;
1734 if (nsk != sk) {
1735 if (tcp_child_process(sk, nsk, skb)) {
1736 rsk = nsk;
1737 goto reset;
1738 }
1739 return 0;
1740 }
1741 } else
1742 sock_rps_save_rxhash(sk, skb);
1743
1744 if (tcp_rcv_state_process(sk, skb)) {
1745 rsk = sk;
1746 goto reset;
1747 }
1748 return 0;
1749
1750reset:
1751 tcp_v4_send_reset(rsk, skb);
1752discard:
1753 kfree_skb_reason(skb, reason);
1754 /* Be careful here. If this function gets more complicated and
1755 * gcc suffers from register pressure on the x86, sk (in %ebx)
1756 * might be destroyed here. This current version compiles correctly,
1757 * but you have been warned.
1758 */
1759 return 0;
1760
1761csum_err:
1762 reason = SKB_DROP_REASON_TCP_CSUM;
1763 trace_tcp_bad_csum(skb);
1764 TCP_INC_STATS(sock_net(sk), TCP_MIB_CSUMERRORS);
1765 TCP_INC_STATS(sock_net(sk), TCP_MIB_INERRS);
1766 goto discard;
1767}
1768EXPORT_SYMBOL(tcp_v4_do_rcv);
1769
1770int tcp_v4_early_demux(struct sk_buff *skb)
1771{
1772 struct net *net = dev_net(skb->dev);
1773 const struct iphdr *iph;
1774 const struct tcphdr *th;
1775 struct sock *sk;
1776
1777 if (skb->pkt_type != PACKET_HOST)
1778 return 0;
1779
1780 if (!pskb_may_pull(skb, skb_transport_offset(skb) + sizeof(struct tcphdr)))
1781 return 0;
1782
1783 iph = ip_hdr(skb);
1784 th = tcp_hdr(skb);
1785
1786 if (th->doff < sizeof(struct tcphdr) / 4)
1787 return 0;
1788
1789 sk = __inet_lookup_established(net, net->ipv4.tcp_death_row.hashinfo,
1790 iph->saddr, th->source,
1791 iph->daddr, ntohs(th->dest),
1792 skb->skb_iif, inet_sdif(skb));
1793 if (sk) {
1794 skb->sk = sk;
1795 skb->destructor = sock_edemux;
1796 if (sk_fullsock(sk)) {
1797 struct dst_entry *dst = rcu_dereference(sk->sk_rx_dst);
1798
1799 if (dst)
1800 dst = dst_check(dst, 0);
1801 if (dst &&
1802 sk->sk_rx_dst_ifindex == skb->skb_iif)
1803 skb_dst_set_noref(skb, dst);
1804 }
1805 }
1806 return 0;
1807}
1808
1809bool tcp_add_backlog(struct sock *sk, struct sk_buff *skb,
1810 enum skb_drop_reason *reason)
1811{
1812 u32 limit, tail_gso_size, tail_gso_segs;
1813 struct skb_shared_info *shinfo;
1814 const struct tcphdr *th;
1815 struct tcphdr *thtail;
1816 struct sk_buff *tail;
1817 unsigned int hdrlen;
1818 bool fragstolen;
1819 u32 gso_segs;
1820 u32 gso_size;
1821 int delta;
1822
1823 /* In case all data was pulled from skb frags (in __pskb_pull_tail()),
1824 * we can fix skb->truesize to its real value to avoid future drops.
1825 * This is valid because skb is not yet charged to the socket.
1826 * It has been noticed pure SACK packets were sometimes dropped
1827 * (if cooked by drivers without copybreak feature).
1828 */
1829 skb_condense(skb);
1830
1831 skb_dst_drop(skb);
1832
1833 if (unlikely(tcp_checksum_complete(skb))) {
1834 bh_unlock_sock(sk);
1835 trace_tcp_bad_csum(skb);
1836 *reason = SKB_DROP_REASON_TCP_CSUM;
1837 __TCP_INC_STATS(sock_net(sk), TCP_MIB_CSUMERRORS);
1838 __TCP_INC_STATS(sock_net(sk), TCP_MIB_INERRS);
1839 return true;
1840 }
1841
1842 /* Attempt coalescing to last skb in backlog, even if we are
1843 * above the limits.
1844 * This is okay because skb capacity is limited to MAX_SKB_FRAGS.
1845 */
1846 th = (const struct tcphdr *)skb->data;
1847 hdrlen = th->doff * 4;
1848
1849 tail = sk->sk_backlog.tail;
1850 if (!tail)
1851 goto no_coalesce;
1852 thtail = (struct tcphdr *)tail->data;
1853
1854 if (TCP_SKB_CB(tail)->end_seq != TCP_SKB_CB(skb)->seq ||
1855 TCP_SKB_CB(tail)->ip_dsfield != TCP_SKB_CB(skb)->ip_dsfield ||
1856 ((TCP_SKB_CB(tail)->tcp_flags |
1857 TCP_SKB_CB(skb)->tcp_flags) & (TCPHDR_SYN | TCPHDR_RST | TCPHDR_URG)) ||
1858 !((TCP_SKB_CB(tail)->tcp_flags &
1859 TCP_SKB_CB(skb)->tcp_flags) & TCPHDR_ACK) ||
1860 ((TCP_SKB_CB(tail)->tcp_flags ^
1861 TCP_SKB_CB(skb)->tcp_flags) & (TCPHDR_ECE | TCPHDR_CWR)) ||
1862#ifdef CONFIG_TLS_DEVICE
1863 tail->decrypted != skb->decrypted ||
1864#endif
1865 thtail->doff != th->doff ||
1866 memcmp(thtail + 1, th + 1, hdrlen - sizeof(*th)))
1867 goto no_coalesce;
1868
1869 __skb_pull(skb, hdrlen);
1870
1871 shinfo = skb_shinfo(skb);
1872 gso_size = shinfo->gso_size ?: skb->len;
1873 gso_segs = shinfo->gso_segs ?: 1;
1874
1875 shinfo = skb_shinfo(tail);
1876 tail_gso_size = shinfo->gso_size ?: (tail->len - hdrlen);
1877 tail_gso_segs = shinfo->gso_segs ?: 1;
1878
1879 if (skb_try_coalesce(tail, skb, &fragstolen, &delta)) {
1880 TCP_SKB_CB(tail)->end_seq = TCP_SKB_CB(skb)->end_seq;
1881
1882 if (likely(!before(TCP_SKB_CB(skb)->ack_seq, TCP_SKB_CB(tail)->ack_seq))) {
1883 TCP_SKB_CB(tail)->ack_seq = TCP_SKB_CB(skb)->ack_seq;
1884 thtail->window = th->window;
1885 }
1886
1887 /* We have to update both TCP_SKB_CB(tail)->tcp_flags and
1888 * thtail->fin, so that the fast path in tcp_rcv_established()
1889 * is not entered if we append a packet with a FIN.
1890 * SYN, RST, URG are not present.
1891 * ACK is set on both packets.
1892 * PSH : we do not really care in TCP stack,
1893 * at least for 'GRO' packets.
1894 */
1895 thtail->fin |= th->fin;
1896 TCP_SKB_CB(tail)->tcp_flags |= TCP_SKB_CB(skb)->tcp_flags;
1897
1898 if (TCP_SKB_CB(skb)->has_rxtstamp) {
1899 TCP_SKB_CB(tail)->has_rxtstamp = true;
1900 tail->tstamp = skb->tstamp;
1901 skb_hwtstamps(tail)->hwtstamp = skb_hwtstamps(skb)->hwtstamp;
1902 }
1903
1904 /* Not as strict as GRO. We only need to carry mss max value */
1905 shinfo->gso_size = max(gso_size, tail_gso_size);
1906 shinfo->gso_segs = min_t(u32, gso_segs + tail_gso_segs, 0xFFFF);
1907
1908 sk->sk_backlog.len += delta;
1909 __NET_INC_STATS(sock_net(sk),
1910 LINUX_MIB_TCPBACKLOGCOALESCE);
1911 kfree_skb_partial(skb, fragstolen);
1912 return false;
1913 }
1914 __skb_push(skb, hdrlen);
1915
1916no_coalesce:
1917 limit = (u32)READ_ONCE(sk->sk_rcvbuf) + (u32)(READ_ONCE(sk->sk_sndbuf) >> 1);
1918
1919 /* Only socket owner can try to collapse/prune rx queues
1920 * to reduce memory overhead, so add a little headroom here.
1921 * Few sockets backlog are possibly concurrently non empty.
1922 */
1923 limit += 64 * 1024;
1924
1925 if (unlikely(sk_add_backlog(sk, skb, limit))) {
1926 bh_unlock_sock(sk);
1927 *reason = SKB_DROP_REASON_SOCKET_BACKLOG;
1928 __NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPBACKLOGDROP);
1929 return true;
1930 }
1931 return false;
1932}
1933EXPORT_SYMBOL(tcp_add_backlog);
1934
1935int tcp_filter(struct sock *sk, struct sk_buff *skb)
1936{
1937 struct tcphdr *th = (struct tcphdr *)skb->data;
1938
1939 return sk_filter_trim_cap(sk, skb, th->doff * 4);
1940}
1941EXPORT_SYMBOL(tcp_filter);
1942
1943static void tcp_v4_restore_cb(struct sk_buff *skb)
1944{
1945 memmove(IPCB(skb), &TCP_SKB_CB(skb)->header.h4,
1946 sizeof(struct inet_skb_parm));
1947}
1948
1949static void tcp_v4_fill_cb(struct sk_buff *skb, const struct iphdr *iph,
1950 const struct tcphdr *th)
1951{
1952 /* This is tricky : We move IPCB at its correct location into TCP_SKB_CB()
1953 * barrier() makes sure compiler wont play fool^Waliasing games.
1954 */
1955 memmove(&TCP_SKB_CB(skb)->header.h4, IPCB(skb),
1956 sizeof(struct inet_skb_parm));
1957 barrier();
1958
1959 TCP_SKB_CB(skb)->seq = ntohl(th->seq);
1960 TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
1961 skb->len - th->doff * 4);
1962 TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
1963 TCP_SKB_CB(skb)->tcp_flags = tcp_flag_byte(th);
1964 TCP_SKB_CB(skb)->tcp_tw_isn = 0;
1965 TCP_SKB_CB(skb)->ip_dsfield = ipv4_get_dsfield(iph);
1966 TCP_SKB_CB(skb)->sacked = 0;
1967 TCP_SKB_CB(skb)->has_rxtstamp =
1968 skb->tstamp || skb_hwtstamps(skb)->hwtstamp;
1969}
1970
1971/*
1972 * From tcp_input.c
1973 */
1974
1975int tcp_v4_rcv(struct sk_buff *skb)
1976{
1977 struct net *net = dev_net(skb->dev);
1978 enum skb_drop_reason drop_reason;
1979 int sdif = inet_sdif(skb);
1980 int dif = inet_iif(skb);
1981 const struct iphdr *iph;
1982 const struct tcphdr *th;
1983 bool refcounted;
1984 struct sock *sk;
1985 int ret;
1986
1987 drop_reason = SKB_DROP_REASON_NOT_SPECIFIED;
1988 if (skb->pkt_type != PACKET_HOST)
1989 goto discard_it;
1990
1991 /* Count it even if it's bad */
1992 __TCP_INC_STATS(net, TCP_MIB_INSEGS);
1993
1994 if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
1995 goto discard_it;
1996
1997 th = (const struct tcphdr *)skb->data;
1998
1999 if (unlikely(th->doff < sizeof(struct tcphdr) / 4)) {
2000 drop_reason = SKB_DROP_REASON_PKT_TOO_SMALL;
2001 goto bad_packet;
2002 }
2003 if (!pskb_may_pull(skb, th->doff * 4))
2004 goto discard_it;
2005
2006 /* An explanation is required here, I think.
2007 * Packet length and doff are validated by header prediction,
2008 * provided case of th->doff==0 is eliminated.
2009 * So, we defer the checks. */
2010
2011 if (skb_checksum_init(skb, IPPROTO_TCP, inet_compute_pseudo))
2012 goto csum_error;
2013
2014 th = (const struct tcphdr *)skb->data;
2015 iph = ip_hdr(skb);
2016lookup:
2017 sk = __inet_lookup_skb(net->ipv4.tcp_death_row.hashinfo,
2018 skb, __tcp_hdrlen(th), th->source,
2019 th->dest, sdif, &refcounted);
2020 if (!sk)
2021 goto no_tcp_socket;
2022
2023process:
2024 if (sk->sk_state == TCP_TIME_WAIT)
2025 goto do_time_wait;
2026
2027 if (sk->sk_state == TCP_NEW_SYN_RECV) {
2028 struct request_sock *req = inet_reqsk(sk);
2029 bool req_stolen = false;
2030 struct sock *nsk;
2031
2032 sk = req->rsk_listener;
2033 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
2034 drop_reason = SKB_DROP_REASON_XFRM_POLICY;
2035 else
2036 drop_reason = tcp_inbound_md5_hash(sk, skb,
2037 &iph->saddr, &iph->daddr,
2038 AF_INET, dif, sdif);
2039 if (unlikely(drop_reason)) {
2040 sk_drops_add(sk, skb);
2041 reqsk_put(req);
2042 goto discard_it;
2043 }
2044 if (tcp_checksum_complete(skb)) {
2045 reqsk_put(req);
2046 goto csum_error;
2047 }
2048 if (unlikely(sk->sk_state != TCP_LISTEN)) {
2049 nsk = reuseport_migrate_sock(sk, req_to_sk(req), skb);
2050 if (!nsk) {
2051 inet_csk_reqsk_queue_drop_and_put(sk, req);
2052 goto lookup;
2053 }
2054 sk = nsk;
2055 /* reuseport_migrate_sock() has already held one sk_refcnt
2056 * before returning.
2057 */
2058 } else {
2059 /* We own a reference on the listener, increase it again
2060 * as we might lose it too soon.
2061 */
2062 sock_hold(sk);
2063 }
2064 refcounted = true;
2065 nsk = NULL;
2066 if (!tcp_filter(sk, skb)) {
2067 th = (const struct tcphdr *)skb->data;
2068 iph = ip_hdr(skb);
2069 tcp_v4_fill_cb(skb, iph, th);
2070 nsk = tcp_check_req(sk, skb, req, false, &req_stolen);
2071 } else {
2072 drop_reason = SKB_DROP_REASON_SOCKET_FILTER;
2073 }
2074 if (!nsk) {
2075 reqsk_put(req);
2076 if (req_stolen) {
2077 /* Another cpu got exclusive access to req
2078 * and created a full blown socket.
2079 * Try to feed this packet to this socket
2080 * instead of discarding it.
2081 */
2082 tcp_v4_restore_cb(skb);
2083 sock_put(sk);
2084 goto lookup;
2085 }
2086 goto discard_and_relse;
2087 }
2088 nf_reset_ct(skb);
2089 if (nsk == sk) {
2090 reqsk_put(req);
2091 tcp_v4_restore_cb(skb);
2092 } else if (tcp_child_process(sk, nsk, skb)) {
2093 tcp_v4_send_reset(nsk, skb);
2094 goto discard_and_relse;
2095 } else {
2096 sock_put(sk);
2097 return 0;
2098 }
2099 }
2100
2101 if (static_branch_unlikely(&ip4_min_ttl)) {
2102 /* min_ttl can be changed concurrently from do_ip_setsockopt() */
2103 if (unlikely(iph->ttl < READ_ONCE(inet_sk(sk)->min_ttl))) {
2104 __NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP);
2105 goto discard_and_relse;
2106 }
2107 }
2108
2109 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb)) {
2110 drop_reason = SKB_DROP_REASON_XFRM_POLICY;
2111 goto discard_and_relse;
2112 }
2113
2114 drop_reason = tcp_inbound_md5_hash(sk, skb, &iph->saddr,
2115 &iph->daddr, AF_INET, dif, sdif);
2116 if (drop_reason)
2117 goto discard_and_relse;
2118
2119 nf_reset_ct(skb);
2120
2121 if (tcp_filter(sk, skb)) {
2122 drop_reason = SKB_DROP_REASON_SOCKET_FILTER;
2123 goto discard_and_relse;
2124 }
2125 th = (const struct tcphdr *)skb->data;
2126 iph = ip_hdr(skb);
2127 tcp_v4_fill_cb(skb, iph, th);
2128
2129 skb->dev = NULL;
2130
2131 if (sk->sk_state == TCP_LISTEN) {
2132 ret = tcp_v4_do_rcv(sk, skb);
2133 goto put_and_return;
2134 }
2135
2136 sk_incoming_cpu_update(sk);
2137
2138 bh_lock_sock_nested(sk);
2139 tcp_segs_in(tcp_sk(sk), skb);
2140 ret = 0;
2141 if (!sock_owned_by_user(sk)) {
2142 ret = tcp_v4_do_rcv(sk, skb);
2143 } else {
2144 if (tcp_add_backlog(sk, skb, &drop_reason))
2145 goto discard_and_relse;
2146 }
2147 bh_unlock_sock(sk);
2148
2149put_and_return:
2150 if (refcounted)
2151 sock_put(sk);
2152
2153 return ret;
2154
2155no_tcp_socket:
2156 drop_reason = SKB_DROP_REASON_NO_SOCKET;
2157 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
2158 goto discard_it;
2159
2160 tcp_v4_fill_cb(skb, iph, th);
2161
2162 if (tcp_checksum_complete(skb)) {
2163csum_error:
2164 drop_reason = SKB_DROP_REASON_TCP_CSUM;
2165 trace_tcp_bad_csum(skb);
2166 __TCP_INC_STATS(net, TCP_MIB_CSUMERRORS);
2167bad_packet:
2168 __TCP_INC_STATS(net, TCP_MIB_INERRS);
2169 } else {
2170 tcp_v4_send_reset(NULL, skb);
2171 }
2172
2173discard_it:
2174 SKB_DR_OR(drop_reason, NOT_SPECIFIED);
2175 /* Discard frame. */
2176 kfree_skb_reason(skb, drop_reason);
2177 return 0;
2178
2179discard_and_relse:
2180 sk_drops_add(sk, skb);
2181 if (refcounted)
2182 sock_put(sk);
2183 goto discard_it;
2184
2185do_time_wait:
2186 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
2187 drop_reason = SKB_DROP_REASON_XFRM_POLICY;
2188 inet_twsk_put(inet_twsk(sk));
2189 goto discard_it;
2190 }
2191
2192 tcp_v4_fill_cb(skb, iph, th);
2193
2194 if (tcp_checksum_complete(skb)) {
2195 inet_twsk_put(inet_twsk(sk));
2196 goto csum_error;
2197 }
2198 switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) {
2199 case TCP_TW_SYN: {
2200 struct sock *sk2 = inet_lookup_listener(net,
2201 net->ipv4.tcp_death_row.hashinfo,
2202 skb, __tcp_hdrlen(th),
2203 iph->saddr, th->source,
2204 iph->daddr, th->dest,
2205 inet_iif(skb),
2206 sdif);
2207 if (sk2) {
2208 inet_twsk_deschedule_put(inet_twsk(sk));
2209 sk = sk2;
2210 tcp_v4_restore_cb(skb);
2211 refcounted = false;
2212 goto process;
2213 }
2214 }
2215 /* to ACK */
2216 fallthrough;
2217 case TCP_TW_ACK:
2218 tcp_v4_timewait_ack(sk, skb);
2219 break;
2220 case TCP_TW_RST:
2221 tcp_v4_send_reset(sk, skb);
2222 inet_twsk_deschedule_put(inet_twsk(sk));
2223 goto discard_it;
2224 case TCP_TW_SUCCESS:;
2225 }
2226 goto discard_it;
2227}
2228
2229static struct timewait_sock_ops tcp_timewait_sock_ops = {
2230 .twsk_obj_size = sizeof(struct tcp_timewait_sock),
2231 .twsk_unique = tcp_twsk_unique,
2232 .twsk_destructor= tcp_twsk_destructor,
2233};
2234
2235void inet_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb)
2236{
2237 struct dst_entry *dst = skb_dst(skb);
2238
2239 if (dst && dst_hold_safe(dst)) {
2240 rcu_assign_pointer(sk->sk_rx_dst, dst);
2241 sk->sk_rx_dst_ifindex = skb->skb_iif;
2242 }
2243}
2244EXPORT_SYMBOL(inet_sk_rx_dst_set);
2245
2246const struct inet_connection_sock_af_ops ipv4_specific = {
2247 .queue_xmit = ip_queue_xmit,
2248 .send_check = tcp_v4_send_check,
2249 .rebuild_header = inet_sk_rebuild_header,
2250 .sk_rx_dst_set = inet_sk_rx_dst_set,
2251 .conn_request = tcp_v4_conn_request,
2252 .syn_recv_sock = tcp_v4_syn_recv_sock,
2253 .net_header_len = sizeof(struct iphdr),
2254 .setsockopt = ip_setsockopt,
2255 .getsockopt = ip_getsockopt,
2256 .addr2sockaddr = inet_csk_addr2sockaddr,
2257 .sockaddr_len = sizeof(struct sockaddr_in),
2258 .mtu_reduced = tcp_v4_mtu_reduced,
2259};
2260EXPORT_SYMBOL(ipv4_specific);
2261
2262#ifdef CONFIG_TCP_MD5SIG
2263static const struct tcp_sock_af_ops tcp_sock_ipv4_specific = {
2264 .md5_lookup = tcp_v4_md5_lookup,
2265 .calc_md5_hash = tcp_v4_md5_hash_skb,
2266 .md5_parse = tcp_v4_parse_md5_keys,
2267};
2268#endif
2269
2270/* NOTE: A lot of things set to zero explicitly by call to
2271 * sk_alloc() so need not be done here.
2272 */
2273static int tcp_v4_init_sock(struct sock *sk)
2274{
2275 struct inet_connection_sock *icsk = inet_csk(sk);
2276
2277 tcp_init_sock(sk);
2278
2279 icsk->icsk_af_ops = &ipv4_specific;
2280
2281#ifdef CONFIG_TCP_MD5SIG
2282 tcp_sk(sk)->af_specific = &tcp_sock_ipv4_specific;
2283#endif
2284
2285 return 0;
2286}
2287
2288void tcp_v4_destroy_sock(struct sock *sk)
2289{
2290 struct tcp_sock *tp = tcp_sk(sk);
2291
2292 trace_tcp_destroy_sock(sk);
2293
2294 tcp_clear_xmit_timers(sk);
2295
2296 tcp_cleanup_congestion_control(sk);
2297
2298 tcp_cleanup_ulp(sk);
2299
2300 /* Cleanup up the write buffer. */
2301 tcp_write_queue_purge(sk);
2302
2303 /* Check if we want to disable active TFO */
2304 tcp_fastopen_active_disable_ofo_check(sk);
2305
2306 /* Cleans up our, hopefully empty, out_of_order_queue. */
2307 skb_rbtree_purge(&tp->out_of_order_queue);
2308
2309#ifdef CONFIG_TCP_MD5SIG
2310 /* Clean up the MD5 key list, if any */
2311 if (tp->md5sig_info) {
2312 tcp_clear_md5_list(sk);
2313 kfree_rcu(rcu_dereference_protected(tp->md5sig_info, 1), rcu);
2314 tp->md5sig_info = NULL;
2315 static_branch_slow_dec_deferred(&tcp_md5_needed);
2316 }
2317#endif
2318
2319 /* Clean up a referenced TCP bind bucket. */
2320 if (inet_csk(sk)->icsk_bind_hash)
2321 inet_put_port(sk);
2322
2323 BUG_ON(rcu_access_pointer(tp->fastopen_rsk));
2324
2325 /* If socket is aborted during connect operation */
2326 tcp_free_fastopen_req(tp);
2327 tcp_fastopen_destroy_cipher(sk);
2328 tcp_saved_syn_free(tp);
2329
2330 sk_sockets_allocated_dec(sk);
2331}
2332EXPORT_SYMBOL(tcp_v4_destroy_sock);
2333
2334#ifdef CONFIG_PROC_FS
2335/* Proc filesystem TCP sock list dumping. */
2336
2337static unsigned short seq_file_family(const struct seq_file *seq);
2338
2339static bool seq_sk_match(struct seq_file *seq, const struct sock *sk)
2340{
2341 unsigned short family = seq_file_family(seq);
2342
2343 /* AF_UNSPEC is used as a match all */
2344 return ((family == AF_UNSPEC || family == sk->sk_family) &&
2345 net_eq(sock_net(sk), seq_file_net(seq)));
2346}
2347
2348/* Find a non empty bucket (starting from st->bucket)
2349 * and return the first sk from it.
2350 */
2351static void *listening_get_first(struct seq_file *seq)
2352{
2353 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo;
2354 struct tcp_iter_state *st = seq->private;
2355
2356 st->offset = 0;
2357 for (; st->bucket <= hinfo->lhash2_mask; st->bucket++) {
2358 struct inet_listen_hashbucket *ilb2;
2359 struct hlist_nulls_node *node;
2360 struct sock *sk;
2361
2362 ilb2 = &hinfo->lhash2[st->bucket];
2363 if (hlist_nulls_empty(&ilb2->nulls_head))
2364 continue;
2365
2366 spin_lock(&ilb2->lock);
2367 sk_nulls_for_each(sk, node, &ilb2->nulls_head) {
2368 if (seq_sk_match(seq, sk))
2369 return sk;
2370 }
2371 spin_unlock(&ilb2->lock);
2372 }
2373
2374 return NULL;
2375}
2376
2377/* Find the next sk of "cur" within the same bucket (i.e. st->bucket).
2378 * If "cur" is the last one in the st->bucket,
2379 * call listening_get_first() to return the first sk of the next
2380 * non empty bucket.
2381 */
2382static void *listening_get_next(struct seq_file *seq, void *cur)
2383{
2384 struct tcp_iter_state *st = seq->private;
2385 struct inet_listen_hashbucket *ilb2;
2386 struct hlist_nulls_node *node;
2387 struct inet_hashinfo *hinfo;
2388 struct sock *sk = cur;
2389
2390 ++st->num;
2391 ++st->offset;
2392
2393 sk = sk_nulls_next(sk);
2394 sk_nulls_for_each_from(sk, node) {
2395 if (seq_sk_match(seq, sk))
2396 return sk;
2397 }
2398
2399 hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo;
2400 ilb2 = &hinfo->lhash2[st->bucket];
2401 spin_unlock(&ilb2->lock);
2402 ++st->bucket;
2403 return listening_get_first(seq);
2404}
2405
2406static void *listening_get_idx(struct seq_file *seq, loff_t *pos)
2407{
2408 struct tcp_iter_state *st = seq->private;
2409 void *rc;
2410
2411 st->bucket = 0;
2412 st->offset = 0;
2413 rc = listening_get_first(seq);
2414
2415 while (rc && *pos) {
2416 rc = listening_get_next(seq, rc);
2417 --*pos;
2418 }
2419 return rc;
2420}
2421
2422static inline bool empty_bucket(struct inet_hashinfo *hinfo,
2423 const struct tcp_iter_state *st)
2424{
2425 return hlist_nulls_empty(&hinfo->ehash[st->bucket].chain);
2426}
2427
2428/*
2429 * Get first established socket starting from bucket given in st->bucket.
2430 * If st->bucket is zero, the very first socket in the hash is returned.
2431 */
2432static void *established_get_first(struct seq_file *seq)
2433{
2434 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo;
2435 struct tcp_iter_state *st = seq->private;
2436
2437 st->offset = 0;
2438 for (; st->bucket <= hinfo->ehash_mask; ++st->bucket) {
2439 struct sock *sk;
2440 struct hlist_nulls_node *node;
2441 spinlock_t *lock = inet_ehash_lockp(hinfo, st->bucket);
2442
2443 /* Lockless fast path for the common case of empty buckets */
2444 if (empty_bucket(hinfo, st))
2445 continue;
2446
2447 spin_lock_bh(lock);
2448 sk_nulls_for_each(sk, node, &hinfo->ehash[st->bucket].chain) {
2449 if (seq_sk_match(seq, sk))
2450 return sk;
2451 }
2452 spin_unlock_bh(lock);
2453 }
2454
2455 return NULL;
2456}
2457
2458static void *established_get_next(struct seq_file *seq, void *cur)
2459{
2460 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo;
2461 struct tcp_iter_state *st = seq->private;
2462 struct hlist_nulls_node *node;
2463 struct sock *sk = cur;
2464
2465 ++st->num;
2466 ++st->offset;
2467
2468 sk = sk_nulls_next(sk);
2469
2470 sk_nulls_for_each_from(sk, node) {
2471 if (seq_sk_match(seq, sk))
2472 return sk;
2473 }
2474
2475 spin_unlock_bh(inet_ehash_lockp(hinfo, st->bucket));
2476 ++st->bucket;
2477 return established_get_first(seq);
2478}
2479
2480static void *established_get_idx(struct seq_file *seq, loff_t pos)
2481{
2482 struct tcp_iter_state *st = seq->private;
2483 void *rc;
2484
2485 st->bucket = 0;
2486 rc = established_get_first(seq);
2487
2488 while (rc && pos) {
2489 rc = established_get_next(seq, rc);
2490 --pos;
2491 }
2492 return rc;
2493}
2494
2495static void *tcp_get_idx(struct seq_file *seq, loff_t pos)
2496{
2497 void *rc;
2498 struct tcp_iter_state *st = seq->private;
2499
2500 st->state = TCP_SEQ_STATE_LISTENING;
2501 rc = listening_get_idx(seq, &pos);
2502
2503 if (!rc) {
2504 st->state = TCP_SEQ_STATE_ESTABLISHED;
2505 rc = established_get_idx(seq, pos);
2506 }
2507
2508 return rc;
2509}
2510
2511static void *tcp_seek_last_pos(struct seq_file *seq)
2512{
2513 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo;
2514 struct tcp_iter_state *st = seq->private;
2515 int bucket = st->bucket;
2516 int offset = st->offset;
2517 int orig_num = st->num;
2518 void *rc = NULL;
2519
2520 switch (st->state) {
2521 case TCP_SEQ_STATE_LISTENING:
2522 if (st->bucket > hinfo->lhash2_mask)
2523 break;
2524 rc = listening_get_first(seq);
2525 while (offset-- && rc && bucket == st->bucket)
2526 rc = listening_get_next(seq, rc);
2527 if (rc)
2528 break;
2529 st->bucket = 0;
2530 st->state = TCP_SEQ_STATE_ESTABLISHED;
2531 fallthrough;
2532 case TCP_SEQ_STATE_ESTABLISHED:
2533 if (st->bucket > hinfo->ehash_mask)
2534 break;
2535 rc = established_get_first(seq);
2536 while (offset-- && rc && bucket == st->bucket)
2537 rc = established_get_next(seq, rc);
2538 }
2539
2540 st->num = orig_num;
2541
2542 return rc;
2543}
2544
2545void *tcp_seq_start(struct seq_file *seq, loff_t *pos)
2546{
2547 struct tcp_iter_state *st = seq->private;
2548 void *rc;
2549
2550 if (*pos && *pos == st->last_pos) {
2551 rc = tcp_seek_last_pos(seq);
2552 if (rc)
2553 goto out;
2554 }
2555
2556 st->state = TCP_SEQ_STATE_LISTENING;
2557 st->num = 0;
2558 st->bucket = 0;
2559 st->offset = 0;
2560 rc = *pos ? tcp_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
2561
2562out:
2563 st->last_pos = *pos;
2564 return rc;
2565}
2566EXPORT_SYMBOL(tcp_seq_start);
2567
2568void *tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2569{
2570 struct tcp_iter_state *st = seq->private;
2571 void *rc = NULL;
2572
2573 if (v == SEQ_START_TOKEN) {
2574 rc = tcp_get_idx(seq, 0);
2575 goto out;
2576 }
2577
2578 switch (st->state) {
2579 case TCP_SEQ_STATE_LISTENING:
2580 rc = listening_get_next(seq, v);
2581 if (!rc) {
2582 st->state = TCP_SEQ_STATE_ESTABLISHED;
2583 st->bucket = 0;
2584 st->offset = 0;
2585 rc = established_get_first(seq);
2586 }
2587 break;
2588 case TCP_SEQ_STATE_ESTABLISHED:
2589 rc = established_get_next(seq, v);
2590 break;
2591 }
2592out:
2593 ++*pos;
2594 st->last_pos = *pos;
2595 return rc;
2596}
2597EXPORT_SYMBOL(tcp_seq_next);
2598
2599void tcp_seq_stop(struct seq_file *seq, void *v)
2600{
2601 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo;
2602 struct tcp_iter_state *st = seq->private;
2603
2604 switch (st->state) {
2605 case TCP_SEQ_STATE_LISTENING:
2606 if (v != SEQ_START_TOKEN)
2607 spin_unlock(&hinfo->lhash2[st->bucket].lock);
2608 break;
2609 case TCP_SEQ_STATE_ESTABLISHED:
2610 if (v)
2611 spin_unlock_bh(inet_ehash_lockp(hinfo, st->bucket));
2612 break;
2613 }
2614}
2615EXPORT_SYMBOL(tcp_seq_stop);
2616
2617static void get_openreq4(const struct request_sock *req,
2618 struct seq_file *f, int i)
2619{
2620 const struct inet_request_sock *ireq = inet_rsk(req);
2621 long delta = req->rsk_timer.expires - jiffies;
2622
2623 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2624 " %02X %08X:%08X %02X:%08lX %08X %5u %8d %u %d %pK",
2625 i,
2626 ireq->ir_loc_addr,
2627 ireq->ir_num,
2628 ireq->ir_rmt_addr,
2629 ntohs(ireq->ir_rmt_port),
2630 TCP_SYN_RECV,
2631 0, 0, /* could print option size, but that is af dependent. */
2632 1, /* timers active (only the expire timer) */
2633 jiffies_delta_to_clock_t(delta),
2634 req->num_timeout,
2635 from_kuid_munged(seq_user_ns(f),
2636 sock_i_uid(req->rsk_listener)),
2637 0, /* non standard timer */
2638 0, /* open_requests have no inode */
2639 0,
2640 req);
2641}
2642
2643static void get_tcp4_sock(struct sock *sk, struct seq_file *f, int i)
2644{
2645 int timer_active;
2646 unsigned long timer_expires;
2647 const struct tcp_sock *tp = tcp_sk(sk);
2648 const struct inet_connection_sock *icsk = inet_csk(sk);
2649 const struct inet_sock *inet = inet_sk(sk);
2650 const struct fastopen_queue *fastopenq = &icsk->icsk_accept_queue.fastopenq;
2651 __be32 dest = inet->inet_daddr;
2652 __be32 src = inet->inet_rcv_saddr;
2653 __u16 destp = ntohs(inet->inet_dport);
2654 __u16 srcp = ntohs(inet->inet_sport);
2655 int rx_queue;
2656 int state;
2657
2658 if (icsk->icsk_pending == ICSK_TIME_RETRANS ||
2659 icsk->icsk_pending == ICSK_TIME_REO_TIMEOUT ||
2660 icsk->icsk_pending == ICSK_TIME_LOSS_PROBE) {
2661 timer_active = 1;
2662 timer_expires = icsk->icsk_timeout;
2663 } else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
2664 timer_active = 4;
2665 timer_expires = icsk->icsk_timeout;
2666 } else if (timer_pending(&sk->sk_timer)) {
2667 timer_active = 2;
2668 timer_expires = sk->sk_timer.expires;
2669 } else {
2670 timer_active = 0;
2671 timer_expires = jiffies;
2672 }
2673
2674 state = inet_sk_state_load(sk);
2675 if (state == TCP_LISTEN)
2676 rx_queue = READ_ONCE(sk->sk_ack_backlog);
2677 else
2678 /* Because we don't lock the socket,
2679 * we might find a transient negative value.
2680 */
2681 rx_queue = max_t(int, READ_ONCE(tp->rcv_nxt) -
2682 READ_ONCE(tp->copied_seq), 0);
2683
2684 seq_printf(f, "%4d: %08X:%04X %08X:%04X %02X %08X:%08X %02X:%08lX "
2685 "%08X %5u %8d %lu %d %pK %lu %lu %u %u %d",
2686 i, src, srcp, dest, destp, state,
2687 READ_ONCE(tp->write_seq) - tp->snd_una,
2688 rx_queue,
2689 timer_active,
2690 jiffies_delta_to_clock_t(timer_expires - jiffies),
2691 icsk->icsk_retransmits,
2692 from_kuid_munged(seq_user_ns(f), sock_i_uid(sk)),
2693 icsk->icsk_probes_out,
2694 sock_i_ino(sk),
2695 refcount_read(&sk->sk_refcnt), sk,
2696 jiffies_to_clock_t(icsk->icsk_rto),
2697 jiffies_to_clock_t(icsk->icsk_ack.ato),
2698 (icsk->icsk_ack.quick << 1) | inet_csk_in_pingpong_mode(sk),
2699 tcp_snd_cwnd(tp),
2700 state == TCP_LISTEN ?
2701 fastopenq->max_qlen :
2702 (tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh));
2703}
2704
2705static void get_timewait4_sock(const struct inet_timewait_sock *tw,
2706 struct seq_file *f, int i)
2707{
2708 long delta = tw->tw_timer.expires - jiffies;
2709 __be32 dest, src;
2710 __u16 destp, srcp;
2711
2712 dest = tw->tw_daddr;
2713 src = tw->tw_rcv_saddr;
2714 destp = ntohs(tw->tw_dport);
2715 srcp = ntohs(tw->tw_sport);
2716
2717 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2718 " %02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK",
2719 i, src, srcp, dest, destp, tw->tw_substate, 0, 0,
2720 3, jiffies_delta_to_clock_t(delta), 0, 0, 0, 0,
2721 refcount_read(&tw->tw_refcnt), tw);
2722}
2723
2724#define TMPSZ 150
2725
2726static int tcp4_seq_show(struct seq_file *seq, void *v)
2727{
2728 struct tcp_iter_state *st;
2729 struct sock *sk = v;
2730
2731 seq_setwidth(seq, TMPSZ - 1);
2732 if (v == SEQ_START_TOKEN) {
2733 seq_puts(seq, " sl local_address rem_address st tx_queue "
2734 "rx_queue tr tm->when retrnsmt uid timeout "
2735 "inode");
2736 goto out;
2737 }
2738 st = seq->private;
2739
2740 if (sk->sk_state == TCP_TIME_WAIT)
2741 get_timewait4_sock(v, seq, st->num);
2742 else if (sk->sk_state == TCP_NEW_SYN_RECV)
2743 get_openreq4(v, seq, st->num);
2744 else
2745 get_tcp4_sock(v, seq, st->num);
2746out:
2747 seq_pad(seq, '\n');
2748 return 0;
2749}
2750
2751#ifdef CONFIG_BPF_SYSCALL
2752struct bpf_tcp_iter_state {
2753 struct tcp_iter_state state;
2754 unsigned int cur_sk;
2755 unsigned int end_sk;
2756 unsigned int max_sk;
2757 struct sock **batch;
2758 bool st_bucket_done;
2759};
2760
2761struct bpf_iter__tcp {
2762 __bpf_md_ptr(struct bpf_iter_meta *, meta);
2763 __bpf_md_ptr(struct sock_common *, sk_common);
2764 uid_t uid __aligned(8);
2765};
2766
2767static int tcp_prog_seq_show(struct bpf_prog *prog, struct bpf_iter_meta *meta,
2768 struct sock_common *sk_common, uid_t uid)
2769{
2770 struct bpf_iter__tcp ctx;
2771
2772 meta->seq_num--; /* skip SEQ_START_TOKEN */
2773 ctx.meta = meta;
2774 ctx.sk_common = sk_common;
2775 ctx.uid = uid;
2776 return bpf_iter_run_prog(prog, &ctx);
2777}
2778
2779static void bpf_iter_tcp_put_batch(struct bpf_tcp_iter_state *iter)
2780{
2781 while (iter->cur_sk < iter->end_sk)
2782 sock_put(iter->batch[iter->cur_sk++]);
2783}
2784
2785static int bpf_iter_tcp_realloc_batch(struct bpf_tcp_iter_state *iter,
2786 unsigned int new_batch_sz)
2787{
2788 struct sock **new_batch;
2789
2790 new_batch = kvmalloc(sizeof(*new_batch) * new_batch_sz,
2791 GFP_USER | __GFP_NOWARN);
2792 if (!new_batch)
2793 return -ENOMEM;
2794
2795 bpf_iter_tcp_put_batch(iter);
2796 kvfree(iter->batch);
2797 iter->batch = new_batch;
2798 iter->max_sk = new_batch_sz;
2799
2800 return 0;
2801}
2802
2803static unsigned int bpf_iter_tcp_listening_batch(struct seq_file *seq,
2804 struct sock *start_sk)
2805{
2806 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo;
2807 struct bpf_tcp_iter_state *iter = seq->private;
2808 struct tcp_iter_state *st = &iter->state;
2809 struct hlist_nulls_node *node;
2810 unsigned int expected = 1;
2811 struct sock *sk;
2812
2813 sock_hold(start_sk);
2814 iter->batch[iter->end_sk++] = start_sk;
2815
2816 sk = sk_nulls_next(start_sk);
2817 sk_nulls_for_each_from(sk, node) {
2818 if (seq_sk_match(seq, sk)) {
2819 if (iter->end_sk < iter->max_sk) {
2820 sock_hold(sk);
2821 iter->batch[iter->end_sk++] = sk;
2822 }
2823 expected++;
2824 }
2825 }
2826 spin_unlock(&hinfo->lhash2[st->bucket].lock);
2827
2828 return expected;
2829}
2830
2831static unsigned int bpf_iter_tcp_established_batch(struct seq_file *seq,
2832 struct sock *start_sk)
2833{
2834 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo;
2835 struct bpf_tcp_iter_state *iter = seq->private;
2836 struct tcp_iter_state *st = &iter->state;
2837 struct hlist_nulls_node *node;
2838 unsigned int expected = 1;
2839 struct sock *sk;
2840
2841 sock_hold(start_sk);
2842 iter->batch[iter->end_sk++] = start_sk;
2843
2844 sk = sk_nulls_next(start_sk);
2845 sk_nulls_for_each_from(sk, node) {
2846 if (seq_sk_match(seq, sk)) {
2847 if (iter->end_sk < iter->max_sk) {
2848 sock_hold(sk);
2849 iter->batch[iter->end_sk++] = sk;
2850 }
2851 expected++;
2852 }
2853 }
2854 spin_unlock_bh(inet_ehash_lockp(hinfo, st->bucket));
2855
2856 return expected;
2857}
2858
2859static struct sock *bpf_iter_tcp_batch(struct seq_file *seq)
2860{
2861 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo;
2862 struct bpf_tcp_iter_state *iter = seq->private;
2863 struct tcp_iter_state *st = &iter->state;
2864 unsigned int expected;
2865 bool resized = false;
2866 struct sock *sk;
2867
2868 /* The st->bucket is done. Directly advance to the next
2869 * bucket instead of having the tcp_seek_last_pos() to skip
2870 * one by one in the current bucket and eventually find out
2871 * it has to advance to the next bucket.
2872 */
2873 if (iter->st_bucket_done) {
2874 st->offset = 0;
2875 st->bucket++;
2876 if (st->state == TCP_SEQ_STATE_LISTENING &&
2877 st->bucket > hinfo->lhash2_mask) {
2878 st->state = TCP_SEQ_STATE_ESTABLISHED;
2879 st->bucket = 0;
2880 }
2881 }
2882
2883again:
2884 /* Get a new batch */
2885 iter->cur_sk = 0;
2886 iter->end_sk = 0;
2887 iter->st_bucket_done = false;
2888
2889 sk = tcp_seek_last_pos(seq);
2890 if (!sk)
2891 return NULL; /* Done */
2892
2893 if (st->state == TCP_SEQ_STATE_LISTENING)
2894 expected = bpf_iter_tcp_listening_batch(seq, sk);
2895 else
2896 expected = bpf_iter_tcp_established_batch(seq, sk);
2897
2898 if (iter->end_sk == expected) {
2899 iter->st_bucket_done = true;
2900 return sk;
2901 }
2902
2903 if (!resized && !bpf_iter_tcp_realloc_batch(iter, expected * 3 / 2)) {
2904 resized = true;
2905 goto again;
2906 }
2907
2908 return sk;
2909}
2910
2911static void *bpf_iter_tcp_seq_start(struct seq_file *seq, loff_t *pos)
2912{
2913 /* bpf iter does not support lseek, so it always
2914 * continue from where it was stop()-ped.
2915 */
2916 if (*pos)
2917 return bpf_iter_tcp_batch(seq);
2918
2919 return SEQ_START_TOKEN;
2920}
2921
2922static void *bpf_iter_tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2923{
2924 struct bpf_tcp_iter_state *iter = seq->private;
2925 struct tcp_iter_state *st = &iter->state;
2926 struct sock *sk;
2927
2928 /* Whenever seq_next() is called, the iter->cur_sk is
2929 * done with seq_show(), so advance to the next sk in
2930 * the batch.
2931 */
2932 if (iter->cur_sk < iter->end_sk) {
2933 /* Keeping st->num consistent in tcp_iter_state.
2934 * bpf_iter_tcp does not use st->num.
2935 * meta.seq_num is used instead.
2936 */
2937 st->num++;
2938 /* Move st->offset to the next sk in the bucket such that
2939 * the future start() will resume at st->offset in
2940 * st->bucket. See tcp_seek_last_pos().
2941 */
2942 st->offset++;
2943 sock_put(iter->batch[iter->cur_sk++]);
2944 }
2945
2946 if (iter->cur_sk < iter->end_sk)
2947 sk = iter->batch[iter->cur_sk];
2948 else
2949 sk = bpf_iter_tcp_batch(seq);
2950
2951 ++*pos;
2952 /* Keeping st->last_pos consistent in tcp_iter_state.
2953 * bpf iter does not do lseek, so st->last_pos always equals to *pos.
2954 */
2955 st->last_pos = *pos;
2956 return sk;
2957}
2958
2959static int bpf_iter_tcp_seq_show(struct seq_file *seq, void *v)
2960{
2961 struct bpf_iter_meta meta;
2962 struct bpf_prog *prog;
2963 struct sock *sk = v;
2964 bool slow;
2965 uid_t uid;
2966 int ret;
2967
2968 if (v == SEQ_START_TOKEN)
2969 return 0;
2970
2971 if (sk_fullsock(sk))
2972 slow = lock_sock_fast(sk);
2973
2974 if (unlikely(sk_unhashed(sk))) {
2975 ret = SEQ_SKIP;
2976 goto unlock;
2977 }
2978
2979 if (sk->sk_state == TCP_TIME_WAIT) {
2980 uid = 0;
2981 } else if (sk->sk_state == TCP_NEW_SYN_RECV) {
2982 const struct request_sock *req = v;
2983
2984 uid = from_kuid_munged(seq_user_ns(seq),
2985 sock_i_uid(req->rsk_listener));
2986 } else {
2987 uid = from_kuid_munged(seq_user_ns(seq), sock_i_uid(sk));
2988 }
2989
2990 meta.seq = seq;
2991 prog = bpf_iter_get_info(&meta, false);
2992 ret = tcp_prog_seq_show(prog, &meta, v, uid);
2993
2994unlock:
2995 if (sk_fullsock(sk))
2996 unlock_sock_fast(sk, slow);
2997 return ret;
2998
2999}
3000
3001static void bpf_iter_tcp_seq_stop(struct seq_file *seq, void *v)
3002{
3003 struct bpf_tcp_iter_state *iter = seq->private;
3004 struct bpf_iter_meta meta;
3005 struct bpf_prog *prog;
3006
3007 if (!v) {
3008 meta.seq = seq;
3009 prog = bpf_iter_get_info(&meta, true);
3010 if (prog)
3011 (void)tcp_prog_seq_show(prog, &meta, v, 0);
3012 }
3013
3014 if (iter->cur_sk < iter->end_sk) {
3015 bpf_iter_tcp_put_batch(iter);
3016 iter->st_bucket_done = false;
3017 }
3018}
3019
3020static const struct seq_operations bpf_iter_tcp_seq_ops = {
3021 .show = bpf_iter_tcp_seq_show,
3022 .start = bpf_iter_tcp_seq_start,
3023 .next = bpf_iter_tcp_seq_next,
3024 .stop = bpf_iter_tcp_seq_stop,
3025};
3026#endif
3027static unsigned short seq_file_family(const struct seq_file *seq)
3028{
3029 const struct tcp_seq_afinfo *afinfo;
3030
3031#ifdef CONFIG_BPF_SYSCALL
3032 /* Iterated from bpf_iter. Let the bpf prog to filter instead. */
3033 if (seq->op == &bpf_iter_tcp_seq_ops)
3034 return AF_UNSPEC;
3035#endif
3036
3037 /* Iterated from proc fs */
3038 afinfo = pde_data(file_inode(seq->file));
3039 return afinfo->family;
3040}
3041
3042static const struct seq_operations tcp4_seq_ops = {
3043 .show = tcp4_seq_show,
3044 .start = tcp_seq_start,
3045 .next = tcp_seq_next,
3046 .stop = tcp_seq_stop,
3047};
3048
3049static struct tcp_seq_afinfo tcp4_seq_afinfo = {
3050 .family = AF_INET,
3051};
3052
3053static int __net_init tcp4_proc_init_net(struct net *net)
3054{
3055 if (!proc_create_net_data("tcp", 0444, net->proc_net, &tcp4_seq_ops,
3056 sizeof(struct tcp_iter_state), &tcp4_seq_afinfo))
3057 return -ENOMEM;
3058 return 0;
3059}
3060
3061static void __net_exit tcp4_proc_exit_net(struct net *net)
3062{
3063 remove_proc_entry("tcp", net->proc_net);
3064}
3065
3066static struct pernet_operations tcp4_net_ops = {
3067 .init = tcp4_proc_init_net,
3068 .exit = tcp4_proc_exit_net,
3069};
3070
3071int __init tcp4_proc_init(void)
3072{
3073 return register_pernet_subsys(&tcp4_net_ops);
3074}
3075
3076void tcp4_proc_exit(void)
3077{
3078 unregister_pernet_subsys(&tcp4_net_ops);
3079}
3080#endif /* CONFIG_PROC_FS */
3081
3082/* @wake is one when sk_stream_write_space() calls us.
3083 * This sends EPOLLOUT only if notsent_bytes is half the limit.
3084 * This mimics the strategy used in sock_def_write_space().
3085 */
3086bool tcp_stream_memory_free(const struct sock *sk, int wake)
3087{
3088 const struct tcp_sock *tp = tcp_sk(sk);
3089 u32 notsent_bytes = READ_ONCE(tp->write_seq) -
3090 READ_ONCE(tp->snd_nxt);
3091
3092 return (notsent_bytes << wake) < tcp_notsent_lowat(tp);
3093}
3094EXPORT_SYMBOL(tcp_stream_memory_free);
3095
3096struct proto tcp_prot = {
3097 .name = "TCP",
3098 .owner = THIS_MODULE,
3099 .close = tcp_close,
3100 .pre_connect = tcp_v4_pre_connect,
3101 .connect = tcp_v4_connect,
3102 .disconnect = tcp_disconnect,
3103 .accept = inet_csk_accept,
3104 .ioctl = tcp_ioctl,
3105 .init = tcp_v4_init_sock,
3106 .destroy = tcp_v4_destroy_sock,
3107 .shutdown = tcp_shutdown,
3108 .setsockopt = tcp_setsockopt,
3109 .getsockopt = tcp_getsockopt,
3110 .bpf_bypass_getsockopt = tcp_bpf_bypass_getsockopt,
3111 .keepalive = tcp_set_keepalive,
3112 .recvmsg = tcp_recvmsg,
3113 .sendmsg = tcp_sendmsg,
3114 .sendpage = tcp_sendpage,
3115 .backlog_rcv = tcp_v4_do_rcv,
3116 .release_cb = tcp_release_cb,
3117 .hash = inet_hash,
3118 .unhash = inet_unhash,
3119 .get_port = inet_csk_get_port,
3120 .put_port = inet_put_port,
3121#ifdef CONFIG_BPF_SYSCALL
3122 .psock_update_sk_prot = tcp_bpf_update_proto,
3123#endif
3124 .enter_memory_pressure = tcp_enter_memory_pressure,
3125 .leave_memory_pressure = tcp_leave_memory_pressure,
3126 .stream_memory_free = tcp_stream_memory_free,
3127 .sockets_allocated = &tcp_sockets_allocated,
3128 .orphan_count = &tcp_orphan_count,
3129
3130 .memory_allocated = &tcp_memory_allocated,
3131 .per_cpu_fw_alloc = &tcp_memory_per_cpu_fw_alloc,
3132
3133 .memory_pressure = &tcp_memory_pressure,
3134 .sysctl_mem = sysctl_tcp_mem,
3135 .sysctl_wmem_offset = offsetof(struct net, ipv4.sysctl_tcp_wmem),
3136 .sysctl_rmem_offset = offsetof(struct net, ipv4.sysctl_tcp_rmem),
3137 .max_header = MAX_TCP_HEADER,
3138 .obj_size = sizeof(struct tcp_sock),
3139 .slab_flags = SLAB_TYPESAFE_BY_RCU,
3140 .twsk_prot = &tcp_timewait_sock_ops,
3141 .rsk_prot = &tcp_request_sock_ops,
3142 .h.hashinfo = NULL,
3143 .no_autobind = true,
3144 .diag_destroy = tcp_abort,
3145};
3146EXPORT_SYMBOL(tcp_prot);
3147
3148static void __net_exit tcp_sk_exit(struct net *net)
3149{
3150 if (net->ipv4.tcp_congestion_control)
3151 bpf_module_put(net->ipv4.tcp_congestion_control,
3152 net->ipv4.tcp_congestion_control->owner);
3153}
3154
3155static void __net_init tcp_set_hashinfo(struct net *net)
3156{
3157 struct inet_hashinfo *hinfo;
3158 unsigned int ehash_entries;
3159 struct net *old_net;
3160
3161 if (net_eq(net, &init_net))
3162 goto fallback;
3163
3164 old_net = current->nsproxy->net_ns;
3165 ehash_entries = READ_ONCE(old_net->ipv4.sysctl_tcp_child_ehash_entries);
3166 if (!ehash_entries)
3167 goto fallback;
3168
3169 ehash_entries = roundup_pow_of_two(ehash_entries);
3170 hinfo = inet_pernet_hashinfo_alloc(&tcp_hashinfo, ehash_entries);
3171 if (!hinfo) {
3172 pr_warn("Failed to allocate TCP ehash (entries: %u) "
3173 "for a netns, fallback to the global one\n",
3174 ehash_entries);
3175fallback:
3176 hinfo = &tcp_hashinfo;
3177 ehash_entries = tcp_hashinfo.ehash_mask + 1;
3178 }
3179
3180 net->ipv4.tcp_death_row.hashinfo = hinfo;
3181 net->ipv4.tcp_death_row.sysctl_max_tw_buckets = ehash_entries / 2;
3182 net->ipv4.sysctl_max_syn_backlog = max(128U, ehash_entries / 128);
3183}
3184
3185static int __net_init tcp_sk_init(struct net *net)
3186{
3187 net->ipv4.sysctl_tcp_ecn = 2;
3188 net->ipv4.sysctl_tcp_ecn_fallback = 1;
3189
3190 net->ipv4.sysctl_tcp_base_mss = TCP_BASE_MSS;
3191 net->ipv4.sysctl_tcp_min_snd_mss = TCP_MIN_SND_MSS;
3192 net->ipv4.sysctl_tcp_probe_threshold = TCP_PROBE_THRESHOLD;
3193 net->ipv4.sysctl_tcp_probe_interval = TCP_PROBE_INTERVAL;
3194 net->ipv4.sysctl_tcp_mtu_probe_floor = TCP_MIN_SND_MSS;
3195
3196 net->ipv4.sysctl_tcp_keepalive_time = TCP_KEEPALIVE_TIME;
3197 net->ipv4.sysctl_tcp_keepalive_probes = TCP_KEEPALIVE_PROBES;
3198 net->ipv4.sysctl_tcp_keepalive_intvl = TCP_KEEPALIVE_INTVL;
3199
3200 net->ipv4.sysctl_tcp_syn_retries = TCP_SYN_RETRIES;
3201 net->ipv4.sysctl_tcp_synack_retries = TCP_SYNACK_RETRIES;
3202 net->ipv4.sysctl_tcp_syncookies = 1;
3203 net->ipv4.sysctl_tcp_reordering = TCP_FASTRETRANS_THRESH;
3204 net->ipv4.sysctl_tcp_retries1 = TCP_RETR1;
3205 net->ipv4.sysctl_tcp_retries2 = TCP_RETR2;
3206 net->ipv4.sysctl_tcp_orphan_retries = 0;
3207 net->ipv4.sysctl_tcp_fin_timeout = TCP_FIN_TIMEOUT;
3208 net->ipv4.sysctl_tcp_notsent_lowat = UINT_MAX;
3209 net->ipv4.sysctl_tcp_tw_reuse = 2;
3210 net->ipv4.sysctl_tcp_no_ssthresh_metrics_save = 1;
3211
3212 refcount_set(&net->ipv4.tcp_death_row.tw_refcount, 1);
3213 tcp_set_hashinfo(net);
3214
3215 net->ipv4.sysctl_tcp_sack = 1;
3216 net->ipv4.sysctl_tcp_window_scaling = 1;
3217 net->ipv4.sysctl_tcp_timestamps = 1;
3218 net->ipv4.sysctl_tcp_early_retrans = 3;
3219 net->ipv4.sysctl_tcp_recovery = TCP_RACK_LOSS_DETECTION;
3220 net->ipv4.sysctl_tcp_slow_start_after_idle = 1; /* By default, RFC2861 behavior. */
3221 net->ipv4.sysctl_tcp_retrans_collapse = 1;
3222 net->ipv4.sysctl_tcp_max_reordering = 300;
3223 net->ipv4.sysctl_tcp_dsack = 1;
3224 net->ipv4.sysctl_tcp_app_win = 31;
3225 net->ipv4.sysctl_tcp_adv_win_scale = 1;
3226 net->ipv4.sysctl_tcp_frto = 2;
3227 net->ipv4.sysctl_tcp_moderate_rcvbuf = 1;
3228 /* This limits the percentage of the congestion window which we
3229 * will allow a single TSO frame to consume. Building TSO frames
3230 * which are too large can cause TCP streams to be bursty.
3231 */
3232 net->ipv4.sysctl_tcp_tso_win_divisor = 3;
3233 /* Default TSQ limit of 16 TSO segments */
3234 net->ipv4.sysctl_tcp_limit_output_bytes = 16 * 65536;
3235
3236 /* rfc5961 challenge ack rate limiting, per net-ns, disabled by default. */
3237 net->ipv4.sysctl_tcp_challenge_ack_limit = INT_MAX;
3238
3239 net->ipv4.sysctl_tcp_min_tso_segs = 2;
3240 net->ipv4.sysctl_tcp_tso_rtt_log = 9; /* 2^9 = 512 usec */
3241 net->ipv4.sysctl_tcp_min_rtt_wlen = 300;
3242 net->ipv4.sysctl_tcp_autocorking = 1;
3243 net->ipv4.sysctl_tcp_invalid_ratelimit = HZ/2;
3244 net->ipv4.sysctl_tcp_pacing_ss_ratio = 200;
3245 net->ipv4.sysctl_tcp_pacing_ca_ratio = 120;
3246 if (net != &init_net) {
3247 memcpy(net->ipv4.sysctl_tcp_rmem,
3248 init_net.ipv4.sysctl_tcp_rmem,
3249 sizeof(init_net.ipv4.sysctl_tcp_rmem));
3250 memcpy(net->ipv4.sysctl_tcp_wmem,
3251 init_net.ipv4.sysctl_tcp_wmem,
3252 sizeof(init_net.ipv4.sysctl_tcp_wmem));
3253 }
3254 net->ipv4.sysctl_tcp_comp_sack_delay_ns = NSEC_PER_MSEC;
3255 net->ipv4.sysctl_tcp_comp_sack_slack_ns = 100 * NSEC_PER_USEC;
3256 net->ipv4.sysctl_tcp_comp_sack_nr = 44;
3257 net->ipv4.sysctl_tcp_fastopen = TFO_CLIENT_ENABLE;
3258 net->ipv4.sysctl_tcp_fastopen_blackhole_timeout = 0;
3259 atomic_set(&net->ipv4.tfo_active_disable_times, 0);
3260
3261 /* Set default values for PLB */
3262 net->ipv4.sysctl_tcp_plb_enabled = 0; /* Disabled by default */
3263 net->ipv4.sysctl_tcp_plb_idle_rehash_rounds = 3;
3264 net->ipv4.sysctl_tcp_plb_rehash_rounds = 12;
3265 net->ipv4.sysctl_tcp_plb_suspend_rto_sec = 60;
3266 /* Default congestion threshold for PLB to mark a round is 50% */
3267 net->ipv4.sysctl_tcp_plb_cong_thresh = (1 << TCP_PLB_SCALE) / 2;
3268
3269 /* Reno is always built in */
3270 if (!net_eq(net, &init_net) &&
3271 bpf_try_module_get(init_net.ipv4.tcp_congestion_control,
3272 init_net.ipv4.tcp_congestion_control->owner))
3273 net->ipv4.tcp_congestion_control = init_net.ipv4.tcp_congestion_control;
3274 else
3275 net->ipv4.tcp_congestion_control = &tcp_reno;
3276
3277 return 0;
3278}
3279
3280static void __net_exit tcp_sk_exit_batch(struct list_head *net_exit_list)
3281{
3282 struct net *net;
3283
3284 tcp_twsk_purge(net_exit_list, AF_INET);
3285
3286 list_for_each_entry(net, net_exit_list, exit_list) {
3287 inet_pernet_hashinfo_free(net->ipv4.tcp_death_row.hashinfo);
3288 WARN_ON_ONCE(!refcount_dec_and_test(&net->ipv4.tcp_death_row.tw_refcount));
3289 tcp_fastopen_ctx_destroy(net);
3290 }
3291}
3292
3293static struct pernet_operations __net_initdata tcp_sk_ops = {
3294 .init = tcp_sk_init,
3295 .exit = tcp_sk_exit,
3296 .exit_batch = tcp_sk_exit_batch,
3297};
3298
3299#if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS)
3300DEFINE_BPF_ITER_FUNC(tcp, struct bpf_iter_meta *meta,
3301 struct sock_common *sk_common, uid_t uid)
3302
3303#define INIT_BATCH_SZ 16
3304
3305static int bpf_iter_init_tcp(void *priv_data, struct bpf_iter_aux_info *aux)
3306{
3307 struct bpf_tcp_iter_state *iter = priv_data;
3308 int err;
3309
3310 err = bpf_iter_init_seq_net(priv_data, aux);
3311 if (err)
3312 return err;
3313
3314 err = bpf_iter_tcp_realloc_batch(iter, INIT_BATCH_SZ);
3315 if (err) {
3316 bpf_iter_fini_seq_net(priv_data);
3317 return err;
3318 }
3319
3320 return 0;
3321}
3322
3323static void bpf_iter_fini_tcp(void *priv_data)
3324{
3325 struct bpf_tcp_iter_state *iter = priv_data;
3326
3327 bpf_iter_fini_seq_net(priv_data);
3328 kvfree(iter->batch);
3329}
3330
3331static const struct bpf_iter_seq_info tcp_seq_info = {
3332 .seq_ops = &bpf_iter_tcp_seq_ops,
3333 .init_seq_private = bpf_iter_init_tcp,
3334 .fini_seq_private = bpf_iter_fini_tcp,
3335 .seq_priv_size = sizeof(struct bpf_tcp_iter_state),
3336};
3337
3338static const struct bpf_func_proto *
3339bpf_iter_tcp_get_func_proto(enum bpf_func_id func_id,
3340 const struct bpf_prog *prog)
3341{
3342 switch (func_id) {
3343 case BPF_FUNC_setsockopt:
3344 return &bpf_sk_setsockopt_proto;
3345 case BPF_FUNC_getsockopt:
3346 return &bpf_sk_getsockopt_proto;
3347 default:
3348 return NULL;
3349 }
3350}
3351
3352static struct bpf_iter_reg tcp_reg_info = {
3353 .target = "tcp",
3354 .ctx_arg_info_size = 1,
3355 .ctx_arg_info = {
3356 { offsetof(struct bpf_iter__tcp, sk_common),
3357 PTR_TO_BTF_ID_OR_NULL },
3358 },
3359 .get_func_proto = bpf_iter_tcp_get_func_proto,
3360 .seq_info = &tcp_seq_info,
3361};
3362
3363static void __init bpf_iter_register(void)
3364{
3365 tcp_reg_info.ctx_arg_info[0].btf_id = btf_sock_ids[BTF_SOCK_TYPE_SOCK_COMMON];
3366 if (bpf_iter_reg_target(&tcp_reg_info))
3367 pr_warn("Warning: could not register bpf iterator tcp\n");
3368}
3369
3370#endif
3371
3372void __init tcp_v4_init(void)
3373{
3374 int cpu, res;
3375
3376 for_each_possible_cpu(cpu) {
3377 struct sock *sk;
3378
3379 res = inet_ctl_sock_create(&sk, PF_INET, SOCK_RAW,
3380 IPPROTO_TCP, &init_net);
3381 if (res)
3382 panic("Failed to create the TCP control socket.\n");
3383 sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
3384
3385 /* Please enforce IP_DF and IPID==0 for RST and
3386 * ACK sent in SYN-RECV and TIME-WAIT state.
3387 */
3388 inet_sk(sk)->pmtudisc = IP_PMTUDISC_DO;
3389
3390 per_cpu(ipv4_tcp_sk, cpu) = sk;
3391 }
3392 if (register_pernet_subsys(&tcp_sk_ops))
3393 panic("Failed to create the TCP control socket.\n");
3394
3395#if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS)
3396 bpf_iter_register();
3397#endif
3398}
1/*
2 * INET An implementation of the TCP/IP protocol suite for the LINUX
3 * operating system. INET is implemented using the BSD Socket
4 * interface as the means of communication with the user level.
5 *
6 * Implementation of the Transmission Control Protocol(TCP).
7 *
8 * IPv4 specific functions
9 *
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 * This program is free software; you can redistribute it and/or
19 * modify it under the terms of the GNU General Public License
20 * as published by the Free Software Foundation; either version
21 * 2 of the License, or (at your option) any later version.
22 */
23
24/*
25 * Changes:
26 * David S. Miller : New socket lookup architecture.
27 * This code is dedicated to John Dyson.
28 * David S. Miller : Change semantics of established hash,
29 * half is devoted to TIME_WAIT sockets
30 * and the rest go in the other half.
31 * Andi Kleen : Add support for syncookies and fixed
32 * some bugs: ip options weren't passed to
33 * the TCP layer, missed a check for an
34 * ACK bit.
35 * Andi Kleen : Implemented fast path mtu discovery.
36 * Fixed many serious bugs in the
37 * request_sock handling and moved
38 * most of it into the af independent code.
39 * Added tail drop and some other bugfixes.
40 * Added new listen semantics.
41 * Mike McLagan : Routing by source
42 * Juan Jose Ciarlante: ip_dynaddr bits
43 * Andi Kleen: various fixes.
44 * Vitaly E. Lavrov : Transparent proxy revived after year
45 * coma.
46 * Andi Kleen : Fix new listen.
47 * Andi Kleen : Fix accept error reporting.
48 * YOSHIFUJI Hideaki @USAGI and: Support IPV6_V6ONLY socket option, which
49 * Alexey Kuznetsov allow both IPv4 and IPv6 sockets to bind
50 * a single port at the same time.
51 */
52
53#define pr_fmt(fmt) "TCP: " fmt
54
55#include <linux/bottom_half.h>
56#include <linux/types.h>
57#include <linux/fcntl.h>
58#include <linux/module.h>
59#include <linux/random.h>
60#include <linux/cache.h>
61#include <linux/jhash.h>
62#include <linux/init.h>
63#include <linux/times.h>
64#include <linux/slab.h>
65
66#include <net/net_namespace.h>
67#include <net/icmp.h>
68#include <net/inet_hashtables.h>
69#include <net/tcp.h>
70#include <net/transp_v6.h>
71#include <net/ipv6.h>
72#include <net/inet_common.h>
73#include <net/timewait_sock.h>
74#include <net/xfrm.h>
75#include <net/secure_seq.h>
76#include <net/busy_poll.h>
77
78#include <linux/inet.h>
79#include <linux/ipv6.h>
80#include <linux/stddef.h>
81#include <linux/proc_fs.h>
82#include <linux/seq_file.h>
83#include <linux/inetdevice.h>
84
85#include <crypto/hash.h>
86#include <linux/scatterlist.h>
87
88#include <trace/events/tcp.h>
89
90#ifdef CONFIG_TCP_MD5SIG
91static int tcp_v4_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key,
92 __be32 daddr, __be32 saddr, const struct tcphdr *th);
93#endif
94
95struct inet_hashinfo tcp_hashinfo;
96EXPORT_SYMBOL(tcp_hashinfo);
97
98static u32 tcp_v4_init_seq(const struct sk_buff *skb)
99{
100 return secure_tcp_seq(ip_hdr(skb)->daddr,
101 ip_hdr(skb)->saddr,
102 tcp_hdr(skb)->dest,
103 tcp_hdr(skb)->source);
104}
105
106static u32 tcp_v4_init_ts_off(const struct net *net, const struct sk_buff *skb)
107{
108 return secure_tcp_ts_off(net, ip_hdr(skb)->daddr, ip_hdr(skb)->saddr);
109}
110
111int tcp_twsk_unique(struct sock *sk, struct sock *sktw, void *twp)
112{
113 const struct tcp_timewait_sock *tcptw = tcp_twsk(sktw);
114 struct tcp_sock *tp = tcp_sk(sk);
115
116 /* With PAWS, it is safe from the viewpoint
117 of data integrity. Even without PAWS it is safe provided sequence
118 spaces do not overlap i.e. at data rates <= 80Mbit/sec.
119
120 Actually, the idea is close to VJ's one, only timestamp cache is
121 held not per host, but per port pair and TW bucket is used as state
122 holder.
123
124 If TW bucket has been already destroyed we fall back to VJ's scheme
125 and use initial timestamp retrieved from peer table.
126 */
127 if (tcptw->tw_ts_recent_stamp &&
128 (!twp || (sock_net(sk)->ipv4.sysctl_tcp_tw_reuse &&
129 get_seconds() - tcptw->tw_ts_recent_stamp > 1))) {
130 tp->write_seq = tcptw->tw_snd_nxt + 65535 + 2;
131 if (tp->write_seq == 0)
132 tp->write_seq = 1;
133 tp->rx_opt.ts_recent = tcptw->tw_ts_recent;
134 tp->rx_opt.ts_recent_stamp = tcptw->tw_ts_recent_stamp;
135 sock_hold(sktw);
136 return 1;
137 }
138
139 return 0;
140}
141EXPORT_SYMBOL_GPL(tcp_twsk_unique);
142
143static int tcp_v4_pre_connect(struct sock *sk, struct sockaddr *uaddr,
144 int addr_len)
145{
146 /* This check is replicated from tcp_v4_connect() and intended to
147 * prevent BPF program called below from accessing bytes that are out
148 * of the bound specified by user in addr_len.
149 */
150 if (addr_len < sizeof(struct sockaddr_in))
151 return -EINVAL;
152
153 sock_owned_by_me(sk);
154
155 return BPF_CGROUP_RUN_PROG_INET4_CONNECT(sk, uaddr);
156}
157
158/* This will initiate an outgoing connection. */
159int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
160{
161 struct sockaddr_in *usin = (struct sockaddr_in *)uaddr;
162 struct inet_sock *inet = inet_sk(sk);
163 struct tcp_sock *tp = tcp_sk(sk);
164 __be16 orig_sport, orig_dport;
165 __be32 daddr, nexthop;
166 struct flowi4 *fl4;
167 struct rtable *rt;
168 int err;
169 struct ip_options_rcu *inet_opt;
170 struct inet_timewait_death_row *tcp_death_row = &sock_net(sk)->ipv4.tcp_death_row;
171
172 if (addr_len < sizeof(struct sockaddr_in))
173 return -EINVAL;
174
175 if (usin->sin_family != AF_INET)
176 return -EAFNOSUPPORT;
177
178 nexthop = daddr = usin->sin_addr.s_addr;
179 inet_opt = rcu_dereference_protected(inet->inet_opt,
180 lockdep_sock_is_held(sk));
181 if (inet_opt && inet_opt->opt.srr) {
182 if (!daddr)
183 return -EINVAL;
184 nexthop = inet_opt->opt.faddr;
185 }
186
187 orig_sport = inet->inet_sport;
188 orig_dport = usin->sin_port;
189 fl4 = &inet->cork.fl.u.ip4;
190 rt = ip_route_connect(fl4, nexthop, inet->inet_saddr,
191 RT_CONN_FLAGS(sk), sk->sk_bound_dev_if,
192 IPPROTO_TCP,
193 orig_sport, orig_dport, sk);
194 if (IS_ERR(rt)) {
195 err = PTR_ERR(rt);
196 if (err == -ENETUNREACH)
197 IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTNOROUTES);
198 return err;
199 }
200
201 if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) {
202 ip_rt_put(rt);
203 return -ENETUNREACH;
204 }
205
206 if (!inet_opt || !inet_opt->opt.srr)
207 daddr = fl4->daddr;
208
209 if (!inet->inet_saddr)
210 inet->inet_saddr = fl4->saddr;
211 sk_rcv_saddr_set(sk, inet->inet_saddr);
212
213 if (tp->rx_opt.ts_recent_stamp && inet->inet_daddr != daddr) {
214 /* Reset inherited state */
215 tp->rx_opt.ts_recent = 0;
216 tp->rx_opt.ts_recent_stamp = 0;
217 if (likely(!tp->repair))
218 tp->write_seq = 0;
219 }
220
221 inet->inet_dport = usin->sin_port;
222 sk_daddr_set(sk, daddr);
223
224 inet_csk(sk)->icsk_ext_hdr_len = 0;
225 if (inet_opt)
226 inet_csk(sk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
227
228 tp->rx_opt.mss_clamp = TCP_MSS_DEFAULT;
229
230 /* Socket identity is still unknown (sport may be zero).
231 * However we set state to SYN-SENT and not releasing socket
232 * lock select source port, enter ourselves into the hash tables and
233 * complete initialization after this.
234 */
235 tcp_set_state(sk, TCP_SYN_SENT);
236 err = inet_hash_connect(tcp_death_row, sk);
237 if (err)
238 goto failure;
239
240 sk_set_txhash(sk);
241
242 rt = ip_route_newports(fl4, rt, orig_sport, orig_dport,
243 inet->inet_sport, inet->inet_dport, sk);
244 if (IS_ERR(rt)) {
245 err = PTR_ERR(rt);
246 rt = NULL;
247 goto failure;
248 }
249 /* OK, now commit destination to socket. */
250 sk->sk_gso_type = SKB_GSO_TCPV4;
251 sk_setup_caps(sk, &rt->dst);
252 rt = NULL;
253
254 if (likely(!tp->repair)) {
255 if (!tp->write_seq)
256 tp->write_seq = secure_tcp_seq(inet->inet_saddr,
257 inet->inet_daddr,
258 inet->inet_sport,
259 usin->sin_port);
260 tp->tsoffset = secure_tcp_ts_off(sock_net(sk),
261 inet->inet_saddr,
262 inet->inet_daddr);
263 }
264
265 inet->inet_id = tp->write_seq ^ jiffies;
266
267 if (tcp_fastopen_defer_connect(sk, &err))
268 return err;
269 if (err)
270 goto failure;
271
272 err = tcp_connect(sk);
273
274 if (err)
275 goto failure;
276
277 return 0;
278
279failure:
280 /*
281 * This unhashes the socket and releases the local port,
282 * if necessary.
283 */
284 tcp_set_state(sk, TCP_CLOSE);
285 ip_rt_put(rt);
286 sk->sk_route_caps = 0;
287 inet->inet_dport = 0;
288 return err;
289}
290EXPORT_SYMBOL(tcp_v4_connect);
291
292/*
293 * This routine reacts to ICMP_FRAG_NEEDED mtu indications as defined in RFC1191.
294 * It can be called through tcp_release_cb() if socket was owned by user
295 * at the time tcp_v4_err() was called to handle ICMP message.
296 */
297void tcp_v4_mtu_reduced(struct sock *sk)
298{
299 struct inet_sock *inet = inet_sk(sk);
300 struct dst_entry *dst;
301 u32 mtu;
302
303 if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE))
304 return;
305 mtu = tcp_sk(sk)->mtu_info;
306 dst = inet_csk_update_pmtu(sk, mtu);
307 if (!dst)
308 return;
309
310 /* Something is about to be wrong... Remember soft error
311 * for the case, if this connection will not able to recover.
312 */
313 if (mtu < dst_mtu(dst) && ip_dont_fragment(sk, dst))
314 sk->sk_err_soft = EMSGSIZE;
315
316 mtu = dst_mtu(dst);
317
318 if (inet->pmtudisc != IP_PMTUDISC_DONT &&
319 ip_sk_accept_pmtu(sk) &&
320 inet_csk(sk)->icsk_pmtu_cookie > mtu) {
321 tcp_sync_mss(sk, mtu);
322
323 /* Resend the TCP packet because it's
324 * clear that the old packet has been
325 * dropped. This is the new "fast" path mtu
326 * discovery.
327 */
328 tcp_simple_retransmit(sk);
329 } /* else let the usual retransmit timer handle it */
330}
331EXPORT_SYMBOL(tcp_v4_mtu_reduced);
332
333static void do_redirect(struct sk_buff *skb, struct sock *sk)
334{
335 struct dst_entry *dst = __sk_dst_check(sk, 0);
336
337 if (dst)
338 dst->ops->redirect(dst, sk, skb);
339}
340
341
342/* handle ICMP messages on TCP_NEW_SYN_RECV request sockets */
343void tcp_req_err(struct sock *sk, u32 seq, bool abort)
344{
345 struct request_sock *req = inet_reqsk(sk);
346 struct net *net = sock_net(sk);
347
348 /* ICMPs are not backlogged, hence we cannot get
349 * an established socket here.
350 */
351 if (seq != tcp_rsk(req)->snt_isn) {
352 __NET_INC_STATS(net, LINUX_MIB_OUTOFWINDOWICMPS);
353 } else if (abort) {
354 /*
355 * Still in SYN_RECV, just remove it silently.
356 * There is no good way to pass the error to the newly
357 * created socket, and POSIX does not want network
358 * errors returned from accept().
359 */
360 inet_csk_reqsk_queue_drop(req->rsk_listener, req);
361 tcp_listendrop(req->rsk_listener);
362 }
363 reqsk_put(req);
364}
365EXPORT_SYMBOL(tcp_req_err);
366
367/*
368 * This routine is called by the ICMP module when it gets some
369 * sort of error condition. If err < 0 then the socket should
370 * be closed and the error returned to the user. If err > 0
371 * it's just the icmp type << 8 | icmp code. After adjustment
372 * header points to the first 8 bytes of the tcp header. We need
373 * to find the appropriate port.
374 *
375 * The locking strategy used here is very "optimistic". When
376 * someone else accesses the socket the ICMP is just dropped
377 * and for some paths there is no check at all.
378 * A more general error queue to queue errors for later handling
379 * is probably better.
380 *
381 */
382
383void tcp_v4_err(struct sk_buff *icmp_skb, u32 info)
384{
385 const struct iphdr *iph = (const struct iphdr *)icmp_skb->data;
386 struct tcphdr *th = (struct tcphdr *)(icmp_skb->data + (iph->ihl << 2));
387 struct inet_connection_sock *icsk;
388 struct tcp_sock *tp;
389 struct inet_sock *inet;
390 const int type = icmp_hdr(icmp_skb)->type;
391 const int code = icmp_hdr(icmp_skb)->code;
392 struct sock *sk;
393 struct sk_buff *skb;
394 struct request_sock *fastopen;
395 u32 seq, snd_una;
396 s32 remaining;
397 u32 delta_us;
398 int err;
399 struct net *net = dev_net(icmp_skb->dev);
400
401 sk = __inet_lookup_established(net, &tcp_hashinfo, iph->daddr,
402 th->dest, iph->saddr, ntohs(th->source),
403 inet_iif(icmp_skb), 0);
404 if (!sk) {
405 __ICMP_INC_STATS(net, ICMP_MIB_INERRORS);
406 return;
407 }
408 if (sk->sk_state == TCP_TIME_WAIT) {
409 inet_twsk_put(inet_twsk(sk));
410 return;
411 }
412 seq = ntohl(th->seq);
413 if (sk->sk_state == TCP_NEW_SYN_RECV)
414 return tcp_req_err(sk, seq,
415 type == ICMP_PARAMETERPROB ||
416 type == ICMP_TIME_EXCEEDED ||
417 (type == ICMP_DEST_UNREACH &&
418 (code == ICMP_NET_UNREACH ||
419 code == ICMP_HOST_UNREACH)));
420
421 bh_lock_sock(sk);
422 /* If too many ICMPs get dropped on busy
423 * servers this needs to be solved differently.
424 * We do take care of PMTU discovery (RFC1191) special case :
425 * we can receive locally generated ICMP messages while socket is held.
426 */
427 if (sock_owned_by_user(sk)) {
428 if (!(type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED))
429 __NET_INC_STATS(net, LINUX_MIB_LOCKDROPPEDICMPS);
430 }
431 if (sk->sk_state == TCP_CLOSE)
432 goto out;
433
434 if (unlikely(iph->ttl < inet_sk(sk)->min_ttl)) {
435 __NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP);
436 goto out;
437 }
438
439 icsk = inet_csk(sk);
440 tp = tcp_sk(sk);
441 /* XXX (TFO) - tp->snd_una should be ISN (tcp_create_openreq_child() */
442 fastopen = tp->fastopen_rsk;
443 snd_una = fastopen ? tcp_rsk(fastopen)->snt_isn : tp->snd_una;
444 if (sk->sk_state != TCP_LISTEN &&
445 !between(seq, snd_una, tp->snd_nxt)) {
446 __NET_INC_STATS(net, LINUX_MIB_OUTOFWINDOWICMPS);
447 goto out;
448 }
449
450 switch (type) {
451 case ICMP_REDIRECT:
452 if (!sock_owned_by_user(sk))
453 do_redirect(icmp_skb, sk);
454 goto out;
455 case ICMP_SOURCE_QUENCH:
456 /* Just silently ignore these. */
457 goto out;
458 case ICMP_PARAMETERPROB:
459 err = EPROTO;
460 break;
461 case ICMP_DEST_UNREACH:
462 if (code > NR_ICMP_UNREACH)
463 goto out;
464
465 if (code == ICMP_FRAG_NEEDED) { /* PMTU discovery (RFC1191) */
466 /* We are not interested in TCP_LISTEN and open_requests
467 * (SYN-ACKs send out by Linux are always <576bytes so
468 * they should go through unfragmented).
469 */
470 if (sk->sk_state == TCP_LISTEN)
471 goto out;
472
473 tp->mtu_info = info;
474 if (!sock_owned_by_user(sk)) {
475 tcp_v4_mtu_reduced(sk);
476 } else {
477 if (!test_and_set_bit(TCP_MTU_REDUCED_DEFERRED, &sk->sk_tsq_flags))
478 sock_hold(sk);
479 }
480 goto out;
481 }
482
483 err = icmp_err_convert[code].errno;
484 /* check if icmp_skb allows revert of backoff
485 * (see draft-zimmermann-tcp-lcd) */
486 if (code != ICMP_NET_UNREACH && code != ICMP_HOST_UNREACH)
487 break;
488 if (seq != tp->snd_una || !icsk->icsk_retransmits ||
489 !icsk->icsk_backoff || fastopen)
490 break;
491
492 if (sock_owned_by_user(sk))
493 break;
494
495 icsk->icsk_backoff--;
496 icsk->icsk_rto = tp->srtt_us ? __tcp_set_rto(tp) :
497 TCP_TIMEOUT_INIT;
498 icsk->icsk_rto = inet_csk_rto_backoff(icsk, TCP_RTO_MAX);
499
500 skb = tcp_rtx_queue_head(sk);
501 BUG_ON(!skb);
502
503 tcp_mstamp_refresh(tp);
504 delta_us = (u32)(tp->tcp_mstamp - skb->skb_mstamp);
505 remaining = icsk->icsk_rto -
506 usecs_to_jiffies(delta_us);
507
508 if (remaining > 0) {
509 inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
510 remaining, TCP_RTO_MAX);
511 } else {
512 /* RTO revert clocked out retransmission.
513 * Will retransmit now */
514 tcp_retransmit_timer(sk);
515 }
516
517 break;
518 case ICMP_TIME_EXCEEDED:
519 err = EHOSTUNREACH;
520 break;
521 default:
522 goto out;
523 }
524
525 switch (sk->sk_state) {
526 case TCP_SYN_SENT:
527 case TCP_SYN_RECV:
528 /* Only in fast or simultaneous open. If a fast open socket is
529 * is already accepted it is treated as a connected one below.
530 */
531 if (fastopen && !fastopen->sk)
532 break;
533
534 if (!sock_owned_by_user(sk)) {
535 sk->sk_err = err;
536
537 sk->sk_error_report(sk);
538
539 tcp_done(sk);
540 } else {
541 sk->sk_err_soft = err;
542 }
543 goto out;
544 }
545
546 /* If we've already connected we will keep trying
547 * until we time out, or the user gives up.
548 *
549 * rfc1122 4.2.3.9 allows to consider as hard errors
550 * only PROTO_UNREACH and PORT_UNREACH (well, FRAG_FAILED too,
551 * but it is obsoleted by pmtu discovery).
552 *
553 * Note, that in modern internet, where routing is unreliable
554 * and in each dark corner broken firewalls sit, sending random
555 * errors ordered by their masters even this two messages finally lose
556 * their original sense (even Linux sends invalid PORT_UNREACHs)
557 *
558 * Now we are in compliance with RFCs.
559 * --ANK (980905)
560 */
561
562 inet = inet_sk(sk);
563 if (!sock_owned_by_user(sk) && inet->recverr) {
564 sk->sk_err = err;
565 sk->sk_error_report(sk);
566 } else { /* Only an error on timeout */
567 sk->sk_err_soft = err;
568 }
569
570out:
571 bh_unlock_sock(sk);
572 sock_put(sk);
573}
574
575void __tcp_v4_send_check(struct sk_buff *skb, __be32 saddr, __be32 daddr)
576{
577 struct tcphdr *th = tcp_hdr(skb);
578
579 th->check = ~tcp_v4_check(skb->len, saddr, daddr, 0);
580 skb->csum_start = skb_transport_header(skb) - skb->head;
581 skb->csum_offset = offsetof(struct tcphdr, check);
582}
583
584/* This routine computes an IPv4 TCP checksum. */
585void tcp_v4_send_check(struct sock *sk, struct sk_buff *skb)
586{
587 const struct inet_sock *inet = inet_sk(sk);
588
589 __tcp_v4_send_check(skb, inet->inet_saddr, inet->inet_daddr);
590}
591EXPORT_SYMBOL(tcp_v4_send_check);
592
593/*
594 * This routine will send an RST to the other tcp.
595 *
596 * Someone asks: why I NEVER use socket parameters (TOS, TTL etc.)
597 * for reset.
598 * Answer: if a packet caused RST, it is not for a socket
599 * existing in our system, if it is matched to a socket,
600 * it is just duplicate segment or bug in other side's TCP.
601 * So that we build reply only basing on parameters
602 * arrived with segment.
603 * Exception: precedence violation. We do not implement it in any case.
604 */
605
606static void tcp_v4_send_reset(const struct sock *sk, struct sk_buff *skb)
607{
608 const struct tcphdr *th = tcp_hdr(skb);
609 struct {
610 struct tcphdr th;
611#ifdef CONFIG_TCP_MD5SIG
612 __be32 opt[(TCPOLEN_MD5SIG_ALIGNED >> 2)];
613#endif
614 } rep;
615 struct ip_reply_arg arg;
616#ifdef CONFIG_TCP_MD5SIG
617 struct tcp_md5sig_key *key = NULL;
618 const __u8 *hash_location = NULL;
619 unsigned char newhash[16];
620 int genhash;
621 struct sock *sk1 = NULL;
622#endif
623 struct net *net;
624
625 /* Never send a reset in response to a reset. */
626 if (th->rst)
627 return;
628
629 /* If sk not NULL, it means we did a successful lookup and incoming
630 * route had to be correct. prequeue might have dropped our dst.
631 */
632 if (!sk && skb_rtable(skb)->rt_type != RTN_LOCAL)
633 return;
634
635 /* Swap the send and the receive. */
636 memset(&rep, 0, sizeof(rep));
637 rep.th.dest = th->source;
638 rep.th.source = th->dest;
639 rep.th.doff = sizeof(struct tcphdr) / 4;
640 rep.th.rst = 1;
641
642 if (th->ack) {
643 rep.th.seq = th->ack_seq;
644 } else {
645 rep.th.ack = 1;
646 rep.th.ack_seq = htonl(ntohl(th->seq) + th->syn + th->fin +
647 skb->len - (th->doff << 2));
648 }
649
650 memset(&arg, 0, sizeof(arg));
651 arg.iov[0].iov_base = (unsigned char *)&rep;
652 arg.iov[0].iov_len = sizeof(rep.th);
653
654 net = sk ? sock_net(sk) : dev_net(skb_dst(skb)->dev);
655#ifdef CONFIG_TCP_MD5SIG
656 rcu_read_lock();
657 hash_location = tcp_parse_md5sig_option(th);
658 if (sk && sk_fullsock(sk)) {
659 key = tcp_md5_do_lookup(sk, (union tcp_md5_addr *)
660 &ip_hdr(skb)->saddr, AF_INET);
661 } else if (hash_location) {
662 /*
663 * active side is lost. Try to find listening socket through
664 * source port, and then find md5 key through listening socket.
665 * we are not loose security here:
666 * Incoming packet is checked with md5 hash with finding key,
667 * no RST generated if md5 hash doesn't match.
668 */
669 sk1 = __inet_lookup_listener(net, &tcp_hashinfo, NULL, 0,
670 ip_hdr(skb)->saddr,
671 th->source, ip_hdr(skb)->daddr,
672 ntohs(th->source), inet_iif(skb),
673 tcp_v4_sdif(skb));
674 /* don't send rst if it can't find key */
675 if (!sk1)
676 goto out;
677
678 key = tcp_md5_do_lookup(sk1, (union tcp_md5_addr *)
679 &ip_hdr(skb)->saddr, AF_INET);
680 if (!key)
681 goto out;
682
683
684 genhash = tcp_v4_md5_hash_skb(newhash, key, NULL, skb);
685 if (genhash || memcmp(hash_location, newhash, 16) != 0)
686 goto out;
687
688 }
689
690 if (key) {
691 rep.opt[0] = htonl((TCPOPT_NOP << 24) |
692 (TCPOPT_NOP << 16) |
693 (TCPOPT_MD5SIG << 8) |
694 TCPOLEN_MD5SIG);
695 /* Update length and the length the header thinks exists */
696 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED;
697 rep.th.doff = arg.iov[0].iov_len / 4;
698
699 tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[1],
700 key, ip_hdr(skb)->saddr,
701 ip_hdr(skb)->daddr, &rep.th);
702 }
703#endif
704 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
705 ip_hdr(skb)->saddr, /* XXX */
706 arg.iov[0].iov_len, IPPROTO_TCP, 0);
707 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
708 arg.flags = (sk && inet_sk_transparent(sk)) ? IP_REPLY_ARG_NOSRCCHECK : 0;
709
710 /* When socket is gone, all binding information is lost.
711 * routing might fail in this case. No choice here, if we choose to force
712 * input interface, we will misroute in case of asymmetric route.
713 */
714 if (sk) {
715 arg.bound_dev_if = sk->sk_bound_dev_if;
716 if (sk_fullsock(sk))
717 trace_tcp_send_reset(sk, skb);
718 }
719
720 BUILD_BUG_ON(offsetof(struct sock, sk_bound_dev_if) !=
721 offsetof(struct inet_timewait_sock, tw_bound_dev_if));
722
723 arg.tos = ip_hdr(skb)->tos;
724 arg.uid = sock_net_uid(net, sk && sk_fullsock(sk) ? sk : NULL);
725 local_bh_disable();
726 ip_send_unicast_reply(*this_cpu_ptr(net->ipv4.tcp_sk),
727 skb, &TCP_SKB_CB(skb)->header.h4.opt,
728 ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
729 &arg, arg.iov[0].iov_len);
730
731 __TCP_INC_STATS(net, TCP_MIB_OUTSEGS);
732 __TCP_INC_STATS(net, TCP_MIB_OUTRSTS);
733 local_bh_enable();
734
735#ifdef CONFIG_TCP_MD5SIG
736out:
737 rcu_read_unlock();
738#endif
739}
740
741/* The code following below sending ACKs in SYN-RECV and TIME-WAIT states
742 outside socket context is ugly, certainly. What can I do?
743 */
744
745static void tcp_v4_send_ack(const struct sock *sk,
746 struct sk_buff *skb, u32 seq, u32 ack,
747 u32 win, u32 tsval, u32 tsecr, int oif,
748 struct tcp_md5sig_key *key,
749 int reply_flags, u8 tos)
750{
751 const struct tcphdr *th = tcp_hdr(skb);
752 struct {
753 struct tcphdr th;
754 __be32 opt[(TCPOLEN_TSTAMP_ALIGNED >> 2)
755#ifdef CONFIG_TCP_MD5SIG
756 + (TCPOLEN_MD5SIG_ALIGNED >> 2)
757#endif
758 ];
759 } rep;
760 struct net *net = sock_net(sk);
761 struct ip_reply_arg arg;
762
763 memset(&rep.th, 0, sizeof(struct tcphdr));
764 memset(&arg, 0, sizeof(arg));
765
766 arg.iov[0].iov_base = (unsigned char *)&rep;
767 arg.iov[0].iov_len = sizeof(rep.th);
768 if (tsecr) {
769 rep.opt[0] = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
770 (TCPOPT_TIMESTAMP << 8) |
771 TCPOLEN_TIMESTAMP);
772 rep.opt[1] = htonl(tsval);
773 rep.opt[2] = htonl(tsecr);
774 arg.iov[0].iov_len += TCPOLEN_TSTAMP_ALIGNED;
775 }
776
777 /* Swap the send and the receive. */
778 rep.th.dest = th->source;
779 rep.th.source = th->dest;
780 rep.th.doff = arg.iov[0].iov_len / 4;
781 rep.th.seq = htonl(seq);
782 rep.th.ack_seq = htonl(ack);
783 rep.th.ack = 1;
784 rep.th.window = htons(win);
785
786#ifdef CONFIG_TCP_MD5SIG
787 if (key) {
788 int offset = (tsecr) ? 3 : 0;
789
790 rep.opt[offset++] = htonl((TCPOPT_NOP << 24) |
791 (TCPOPT_NOP << 16) |
792 (TCPOPT_MD5SIG << 8) |
793 TCPOLEN_MD5SIG);
794 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED;
795 rep.th.doff = arg.iov[0].iov_len/4;
796
797 tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[offset],
798 key, ip_hdr(skb)->saddr,
799 ip_hdr(skb)->daddr, &rep.th);
800 }
801#endif
802 arg.flags = reply_flags;
803 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
804 ip_hdr(skb)->saddr, /* XXX */
805 arg.iov[0].iov_len, IPPROTO_TCP, 0);
806 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
807 if (oif)
808 arg.bound_dev_if = oif;
809 arg.tos = tos;
810 arg.uid = sock_net_uid(net, sk_fullsock(sk) ? sk : NULL);
811 local_bh_disable();
812 ip_send_unicast_reply(*this_cpu_ptr(net->ipv4.tcp_sk),
813 skb, &TCP_SKB_CB(skb)->header.h4.opt,
814 ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
815 &arg, arg.iov[0].iov_len);
816
817 __TCP_INC_STATS(net, TCP_MIB_OUTSEGS);
818 local_bh_enable();
819}
820
821static void tcp_v4_timewait_ack(struct sock *sk, struct sk_buff *skb)
822{
823 struct inet_timewait_sock *tw = inet_twsk(sk);
824 struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
825
826 tcp_v4_send_ack(sk, skb,
827 tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
828 tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
829 tcp_time_stamp_raw() + tcptw->tw_ts_offset,
830 tcptw->tw_ts_recent,
831 tw->tw_bound_dev_if,
832 tcp_twsk_md5_key(tcptw),
833 tw->tw_transparent ? IP_REPLY_ARG_NOSRCCHECK : 0,
834 tw->tw_tos
835 );
836
837 inet_twsk_put(tw);
838}
839
840static void tcp_v4_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb,
841 struct request_sock *req)
842{
843 /* sk->sk_state == TCP_LISTEN -> for regular TCP_SYN_RECV
844 * sk->sk_state == TCP_SYN_RECV -> for Fast Open.
845 */
846 u32 seq = (sk->sk_state == TCP_LISTEN) ? tcp_rsk(req)->snt_isn + 1 :
847 tcp_sk(sk)->snd_nxt;
848
849 /* RFC 7323 2.3
850 * The window field (SEG.WND) of every outgoing segment, with the
851 * exception of <SYN> segments, MUST be right-shifted by
852 * Rcv.Wind.Shift bits:
853 */
854 tcp_v4_send_ack(sk, skb, seq,
855 tcp_rsk(req)->rcv_nxt,
856 req->rsk_rcv_wnd >> inet_rsk(req)->rcv_wscale,
857 tcp_time_stamp_raw() + tcp_rsk(req)->ts_off,
858 req->ts_recent,
859 0,
860 tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&ip_hdr(skb)->saddr,
861 AF_INET),
862 inet_rsk(req)->no_srccheck ? IP_REPLY_ARG_NOSRCCHECK : 0,
863 ip_hdr(skb)->tos);
864}
865
866/*
867 * Send a SYN-ACK after having received a SYN.
868 * This still operates on a request_sock only, not on a big
869 * socket.
870 */
871static int tcp_v4_send_synack(const struct sock *sk, struct dst_entry *dst,
872 struct flowi *fl,
873 struct request_sock *req,
874 struct tcp_fastopen_cookie *foc,
875 enum tcp_synack_type synack_type)
876{
877 const struct inet_request_sock *ireq = inet_rsk(req);
878 struct flowi4 fl4;
879 int err = -1;
880 struct sk_buff *skb;
881
882 /* First, grab a route. */
883 if (!dst && (dst = inet_csk_route_req(sk, &fl4, req)) == NULL)
884 return -1;
885
886 skb = tcp_make_synack(sk, dst, req, foc, synack_type);
887
888 if (skb) {
889 __tcp_v4_send_check(skb, ireq->ir_loc_addr, ireq->ir_rmt_addr);
890
891 err = ip_build_and_send_pkt(skb, sk, ireq->ir_loc_addr,
892 ireq->ir_rmt_addr,
893 ireq_opt_deref(ireq));
894 err = net_xmit_eval(err);
895 }
896
897 return err;
898}
899
900/*
901 * IPv4 request_sock destructor.
902 */
903static void tcp_v4_reqsk_destructor(struct request_sock *req)
904{
905 kfree(rcu_dereference_protected(inet_rsk(req)->ireq_opt, 1));
906}
907
908#ifdef CONFIG_TCP_MD5SIG
909/*
910 * RFC2385 MD5 checksumming requires a mapping of
911 * IP address->MD5 Key.
912 * We need to maintain these in the sk structure.
913 */
914
915/* Find the Key structure for an address. */
916struct tcp_md5sig_key *tcp_md5_do_lookup(const struct sock *sk,
917 const union tcp_md5_addr *addr,
918 int family)
919{
920 const struct tcp_sock *tp = tcp_sk(sk);
921 struct tcp_md5sig_key *key;
922 const struct tcp_md5sig_info *md5sig;
923 __be32 mask;
924 struct tcp_md5sig_key *best_match = NULL;
925 bool match;
926
927 /* caller either holds rcu_read_lock() or socket lock */
928 md5sig = rcu_dereference_check(tp->md5sig_info,
929 lockdep_sock_is_held(sk));
930 if (!md5sig)
931 return NULL;
932
933 hlist_for_each_entry_rcu(key, &md5sig->head, node) {
934 if (key->family != family)
935 continue;
936
937 if (family == AF_INET) {
938 mask = inet_make_mask(key->prefixlen);
939 match = (key->addr.a4.s_addr & mask) ==
940 (addr->a4.s_addr & mask);
941#if IS_ENABLED(CONFIG_IPV6)
942 } else if (family == AF_INET6) {
943 match = ipv6_prefix_equal(&key->addr.a6, &addr->a6,
944 key->prefixlen);
945#endif
946 } else {
947 match = false;
948 }
949
950 if (match && (!best_match ||
951 key->prefixlen > best_match->prefixlen))
952 best_match = key;
953 }
954 return best_match;
955}
956EXPORT_SYMBOL(tcp_md5_do_lookup);
957
958static struct tcp_md5sig_key *tcp_md5_do_lookup_exact(const struct sock *sk,
959 const union tcp_md5_addr *addr,
960 int family, u8 prefixlen)
961{
962 const struct tcp_sock *tp = tcp_sk(sk);
963 struct tcp_md5sig_key *key;
964 unsigned int size = sizeof(struct in_addr);
965 const struct tcp_md5sig_info *md5sig;
966
967 /* caller either holds rcu_read_lock() or socket lock */
968 md5sig = rcu_dereference_check(tp->md5sig_info,
969 lockdep_sock_is_held(sk));
970 if (!md5sig)
971 return NULL;
972#if IS_ENABLED(CONFIG_IPV6)
973 if (family == AF_INET6)
974 size = sizeof(struct in6_addr);
975#endif
976 hlist_for_each_entry_rcu(key, &md5sig->head, node) {
977 if (key->family != family)
978 continue;
979 if (!memcmp(&key->addr, addr, size) &&
980 key->prefixlen == prefixlen)
981 return key;
982 }
983 return NULL;
984}
985
986struct tcp_md5sig_key *tcp_v4_md5_lookup(const struct sock *sk,
987 const struct sock *addr_sk)
988{
989 const union tcp_md5_addr *addr;
990
991 addr = (const union tcp_md5_addr *)&addr_sk->sk_daddr;
992 return tcp_md5_do_lookup(sk, addr, AF_INET);
993}
994EXPORT_SYMBOL(tcp_v4_md5_lookup);
995
996/* This can be called on a newly created socket, from other files */
997int tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr,
998 int family, u8 prefixlen, const u8 *newkey, u8 newkeylen,
999 gfp_t gfp)
1000{
1001 /* Add Key to the list */
1002 struct tcp_md5sig_key *key;
1003 struct tcp_sock *tp = tcp_sk(sk);
1004 struct tcp_md5sig_info *md5sig;
1005
1006 key = tcp_md5_do_lookup_exact(sk, addr, family, prefixlen);
1007 if (key) {
1008 /* Pre-existing entry - just update that one. */
1009 memcpy(key->key, newkey, newkeylen);
1010 key->keylen = newkeylen;
1011 return 0;
1012 }
1013
1014 md5sig = rcu_dereference_protected(tp->md5sig_info,
1015 lockdep_sock_is_held(sk));
1016 if (!md5sig) {
1017 md5sig = kmalloc(sizeof(*md5sig), gfp);
1018 if (!md5sig)
1019 return -ENOMEM;
1020
1021 sk_nocaps_add(sk, NETIF_F_GSO_MASK);
1022 INIT_HLIST_HEAD(&md5sig->head);
1023 rcu_assign_pointer(tp->md5sig_info, md5sig);
1024 }
1025
1026 key = sock_kmalloc(sk, sizeof(*key), gfp);
1027 if (!key)
1028 return -ENOMEM;
1029 if (!tcp_alloc_md5sig_pool()) {
1030 sock_kfree_s(sk, key, sizeof(*key));
1031 return -ENOMEM;
1032 }
1033
1034 memcpy(key->key, newkey, newkeylen);
1035 key->keylen = newkeylen;
1036 key->family = family;
1037 key->prefixlen = prefixlen;
1038 memcpy(&key->addr, addr,
1039 (family == AF_INET6) ? sizeof(struct in6_addr) :
1040 sizeof(struct in_addr));
1041 hlist_add_head_rcu(&key->node, &md5sig->head);
1042 return 0;
1043}
1044EXPORT_SYMBOL(tcp_md5_do_add);
1045
1046int tcp_md5_do_del(struct sock *sk, const union tcp_md5_addr *addr, int family,
1047 u8 prefixlen)
1048{
1049 struct tcp_md5sig_key *key;
1050
1051 key = tcp_md5_do_lookup_exact(sk, addr, family, prefixlen);
1052 if (!key)
1053 return -ENOENT;
1054 hlist_del_rcu(&key->node);
1055 atomic_sub(sizeof(*key), &sk->sk_omem_alloc);
1056 kfree_rcu(key, rcu);
1057 return 0;
1058}
1059EXPORT_SYMBOL(tcp_md5_do_del);
1060
1061static void tcp_clear_md5_list(struct sock *sk)
1062{
1063 struct tcp_sock *tp = tcp_sk(sk);
1064 struct tcp_md5sig_key *key;
1065 struct hlist_node *n;
1066 struct tcp_md5sig_info *md5sig;
1067
1068 md5sig = rcu_dereference_protected(tp->md5sig_info, 1);
1069
1070 hlist_for_each_entry_safe(key, n, &md5sig->head, node) {
1071 hlist_del_rcu(&key->node);
1072 atomic_sub(sizeof(*key), &sk->sk_omem_alloc);
1073 kfree_rcu(key, rcu);
1074 }
1075}
1076
1077static int tcp_v4_parse_md5_keys(struct sock *sk, int optname,
1078 char __user *optval, int optlen)
1079{
1080 struct tcp_md5sig cmd;
1081 struct sockaddr_in *sin = (struct sockaddr_in *)&cmd.tcpm_addr;
1082 u8 prefixlen = 32;
1083
1084 if (optlen < sizeof(cmd))
1085 return -EINVAL;
1086
1087 if (copy_from_user(&cmd, optval, sizeof(cmd)))
1088 return -EFAULT;
1089
1090 if (sin->sin_family != AF_INET)
1091 return -EINVAL;
1092
1093 if (optname == TCP_MD5SIG_EXT &&
1094 cmd.tcpm_flags & TCP_MD5SIG_FLAG_PREFIX) {
1095 prefixlen = cmd.tcpm_prefixlen;
1096 if (prefixlen > 32)
1097 return -EINVAL;
1098 }
1099
1100 if (!cmd.tcpm_keylen)
1101 return tcp_md5_do_del(sk, (union tcp_md5_addr *)&sin->sin_addr.s_addr,
1102 AF_INET, prefixlen);
1103
1104 if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN)
1105 return -EINVAL;
1106
1107 return tcp_md5_do_add(sk, (union tcp_md5_addr *)&sin->sin_addr.s_addr,
1108 AF_INET, prefixlen, cmd.tcpm_key, cmd.tcpm_keylen,
1109 GFP_KERNEL);
1110}
1111
1112static int tcp_v4_md5_hash_headers(struct tcp_md5sig_pool *hp,
1113 __be32 daddr, __be32 saddr,
1114 const struct tcphdr *th, int nbytes)
1115{
1116 struct tcp4_pseudohdr *bp;
1117 struct scatterlist sg;
1118 struct tcphdr *_th;
1119
1120 bp = hp->scratch;
1121 bp->saddr = saddr;
1122 bp->daddr = daddr;
1123 bp->pad = 0;
1124 bp->protocol = IPPROTO_TCP;
1125 bp->len = cpu_to_be16(nbytes);
1126
1127 _th = (struct tcphdr *)(bp + 1);
1128 memcpy(_th, th, sizeof(*th));
1129 _th->check = 0;
1130
1131 sg_init_one(&sg, bp, sizeof(*bp) + sizeof(*th));
1132 ahash_request_set_crypt(hp->md5_req, &sg, NULL,
1133 sizeof(*bp) + sizeof(*th));
1134 return crypto_ahash_update(hp->md5_req);
1135}
1136
1137static int tcp_v4_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key,
1138 __be32 daddr, __be32 saddr, const struct tcphdr *th)
1139{
1140 struct tcp_md5sig_pool *hp;
1141 struct ahash_request *req;
1142
1143 hp = tcp_get_md5sig_pool();
1144 if (!hp)
1145 goto clear_hash_noput;
1146 req = hp->md5_req;
1147
1148 if (crypto_ahash_init(req))
1149 goto clear_hash;
1150 if (tcp_v4_md5_hash_headers(hp, daddr, saddr, th, th->doff << 2))
1151 goto clear_hash;
1152 if (tcp_md5_hash_key(hp, key))
1153 goto clear_hash;
1154 ahash_request_set_crypt(req, NULL, md5_hash, 0);
1155 if (crypto_ahash_final(req))
1156 goto clear_hash;
1157
1158 tcp_put_md5sig_pool();
1159 return 0;
1160
1161clear_hash:
1162 tcp_put_md5sig_pool();
1163clear_hash_noput:
1164 memset(md5_hash, 0, 16);
1165 return 1;
1166}
1167
1168int tcp_v4_md5_hash_skb(char *md5_hash, const struct tcp_md5sig_key *key,
1169 const struct sock *sk,
1170 const struct sk_buff *skb)
1171{
1172 struct tcp_md5sig_pool *hp;
1173 struct ahash_request *req;
1174 const struct tcphdr *th = tcp_hdr(skb);
1175 __be32 saddr, daddr;
1176
1177 if (sk) { /* valid for establish/request sockets */
1178 saddr = sk->sk_rcv_saddr;
1179 daddr = sk->sk_daddr;
1180 } else {
1181 const struct iphdr *iph = ip_hdr(skb);
1182 saddr = iph->saddr;
1183 daddr = iph->daddr;
1184 }
1185
1186 hp = tcp_get_md5sig_pool();
1187 if (!hp)
1188 goto clear_hash_noput;
1189 req = hp->md5_req;
1190
1191 if (crypto_ahash_init(req))
1192 goto clear_hash;
1193
1194 if (tcp_v4_md5_hash_headers(hp, daddr, saddr, th, skb->len))
1195 goto clear_hash;
1196 if (tcp_md5_hash_skb_data(hp, skb, th->doff << 2))
1197 goto clear_hash;
1198 if (tcp_md5_hash_key(hp, key))
1199 goto clear_hash;
1200 ahash_request_set_crypt(req, NULL, md5_hash, 0);
1201 if (crypto_ahash_final(req))
1202 goto clear_hash;
1203
1204 tcp_put_md5sig_pool();
1205 return 0;
1206
1207clear_hash:
1208 tcp_put_md5sig_pool();
1209clear_hash_noput:
1210 memset(md5_hash, 0, 16);
1211 return 1;
1212}
1213EXPORT_SYMBOL(tcp_v4_md5_hash_skb);
1214
1215#endif
1216
1217/* Called with rcu_read_lock() */
1218static bool tcp_v4_inbound_md5_hash(const struct sock *sk,
1219 const struct sk_buff *skb)
1220{
1221#ifdef CONFIG_TCP_MD5SIG
1222 /*
1223 * This gets called for each TCP segment that arrives
1224 * so we want to be efficient.
1225 * We have 3 drop cases:
1226 * o No MD5 hash and one expected.
1227 * o MD5 hash and we're not expecting one.
1228 * o MD5 hash and its wrong.
1229 */
1230 const __u8 *hash_location = NULL;
1231 struct tcp_md5sig_key *hash_expected;
1232 const struct iphdr *iph = ip_hdr(skb);
1233 const struct tcphdr *th = tcp_hdr(skb);
1234 int genhash;
1235 unsigned char newhash[16];
1236
1237 hash_expected = tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&iph->saddr,
1238 AF_INET);
1239 hash_location = tcp_parse_md5sig_option(th);
1240
1241 /* We've parsed the options - do we have a hash? */
1242 if (!hash_expected && !hash_location)
1243 return false;
1244
1245 if (hash_expected && !hash_location) {
1246 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5NOTFOUND);
1247 return true;
1248 }
1249
1250 if (!hash_expected && hash_location) {
1251 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5UNEXPECTED);
1252 return true;
1253 }
1254
1255 /* Okay, so this is hash_expected and hash_location -
1256 * so we need to calculate the checksum.
1257 */
1258 genhash = tcp_v4_md5_hash_skb(newhash,
1259 hash_expected,
1260 NULL, skb);
1261
1262 if (genhash || memcmp(hash_location, newhash, 16) != 0) {
1263 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5FAILURE);
1264 net_info_ratelimited("MD5 Hash failed for (%pI4, %d)->(%pI4, %d)%s\n",
1265 &iph->saddr, ntohs(th->source),
1266 &iph->daddr, ntohs(th->dest),
1267 genhash ? " tcp_v4_calc_md5_hash failed"
1268 : "");
1269 return true;
1270 }
1271 return false;
1272#endif
1273 return false;
1274}
1275
1276static void tcp_v4_init_req(struct request_sock *req,
1277 const struct sock *sk_listener,
1278 struct sk_buff *skb)
1279{
1280 struct inet_request_sock *ireq = inet_rsk(req);
1281 struct net *net = sock_net(sk_listener);
1282
1283 sk_rcv_saddr_set(req_to_sk(req), ip_hdr(skb)->daddr);
1284 sk_daddr_set(req_to_sk(req), ip_hdr(skb)->saddr);
1285 RCU_INIT_POINTER(ireq->ireq_opt, tcp_v4_save_options(net, skb));
1286}
1287
1288static struct dst_entry *tcp_v4_route_req(const struct sock *sk,
1289 struct flowi *fl,
1290 const struct request_sock *req)
1291{
1292 return inet_csk_route_req(sk, &fl->u.ip4, req);
1293}
1294
1295struct request_sock_ops tcp_request_sock_ops __read_mostly = {
1296 .family = PF_INET,
1297 .obj_size = sizeof(struct tcp_request_sock),
1298 .rtx_syn_ack = tcp_rtx_synack,
1299 .send_ack = tcp_v4_reqsk_send_ack,
1300 .destructor = tcp_v4_reqsk_destructor,
1301 .send_reset = tcp_v4_send_reset,
1302 .syn_ack_timeout = tcp_syn_ack_timeout,
1303};
1304
1305static const struct tcp_request_sock_ops tcp_request_sock_ipv4_ops = {
1306 .mss_clamp = TCP_MSS_DEFAULT,
1307#ifdef CONFIG_TCP_MD5SIG
1308 .req_md5_lookup = tcp_v4_md5_lookup,
1309 .calc_md5_hash = tcp_v4_md5_hash_skb,
1310#endif
1311 .init_req = tcp_v4_init_req,
1312#ifdef CONFIG_SYN_COOKIES
1313 .cookie_init_seq = cookie_v4_init_sequence,
1314#endif
1315 .route_req = tcp_v4_route_req,
1316 .init_seq = tcp_v4_init_seq,
1317 .init_ts_off = tcp_v4_init_ts_off,
1318 .send_synack = tcp_v4_send_synack,
1319};
1320
1321int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
1322{
1323 /* Never answer to SYNs send to broadcast or multicast */
1324 if (skb_rtable(skb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
1325 goto drop;
1326
1327 return tcp_conn_request(&tcp_request_sock_ops,
1328 &tcp_request_sock_ipv4_ops, sk, skb);
1329
1330drop:
1331 tcp_listendrop(sk);
1332 return 0;
1333}
1334EXPORT_SYMBOL(tcp_v4_conn_request);
1335
1336
1337/*
1338 * The three way handshake has completed - we got a valid synack -
1339 * now create the new socket.
1340 */
1341struct sock *tcp_v4_syn_recv_sock(const struct sock *sk, struct sk_buff *skb,
1342 struct request_sock *req,
1343 struct dst_entry *dst,
1344 struct request_sock *req_unhash,
1345 bool *own_req)
1346{
1347 struct inet_request_sock *ireq;
1348 struct inet_sock *newinet;
1349 struct tcp_sock *newtp;
1350 struct sock *newsk;
1351#ifdef CONFIG_TCP_MD5SIG
1352 struct tcp_md5sig_key *key;
1353#endif
1354 struct ip_options_rcu *inet_opt;
1355
1356 if (sk_acceptq_is_full(sk))
1357 goto exit_overflow;
1358
1359 newsk = tcp_create_openreq_child(sk, req, skb);
1360 if (!newsk)
1361 goto exit_nonewsk;
1362
1363 newsk->sk_gso_type = SKB_GSO_TCPV4;
1364 inet_sk_rx_dst_set(newsk, skb);
1365
1366 newtp = tcp_sk(newsk);
1367 newinet = inet_sk(newsk);
1368 ireq = inet_rsk(req);
1369 sk_daddr_set(newsk, ireq->ir_rmt_addr);
1370 sk_rcv_saddr_set(newsk, ireq->ir_loc_addr);
1371 newsk->sk_bound_dev_if = ireq->ir_iif;
1372 newinet->inet_saddr = ireq->ir_loc_addr;
1373 inet_opt = rcu_dereference(ireq->ireq_opt);
1374 RCU_INIT_POINTER(newinet->inet_opt, inet_opt);
1375 newinet->mc_index = inet_iif(skb);
1376 newinet->mc_ttl = ip_hdr(skb)->ttl;
1377 newinet->rcv_tos = ip_hdr(skb)->tos;
1378 inet_csk(newsk)->icsk_ext_hdr_len = 0;
1379 if (inet_opt)
1380 inet_csk(newsk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
1381 newinet->inet_id = newtp->write_seq ^ jiffies;
1382
1383 if (!dst) {
1384 dst = inet_csk_route_child_sock(sk, newsk, req);
1385 if (!dst)
1386 goto put_and_exit;
1387 } else {
1388 /* syncookie case : see end of cookie_v4_check() */
1389 }
1390 sk_setup_caps(newsk, dst);
1391
1392 tcp_ca_openreq_child(newsk, dst);
1393
1394 tcp_sync_mss(newsk, dst_mtu(dst));
1395 newtp->advmss = tcp_mss_clamp(tcp_sk(sk), dst_metric_advmss(dst));
1396
1397 tcp_initialize_rcv_mss(newsk);
1398
1399#ifdef CONFIG_TCP_MD5SIG
1400 /* Copy over the MD5 key from the original socket */
1401 key = tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&newinet->inet_daddr,
1402 AF_INET);
1403 if (key) {
1404 /*
1405 * We're using one, so create a matching key
1406 * on the newsk structure. If we fail to get
1407 * memory, then we end up not copying the key
1408 * across. Shucks.
1409 */
1410 tcp_md5_do_add(newsk, (union tcp_md5_addr *)&newinet->inet_daddr,
1411 AF_INET, 32, key->key, key->keylen, GFP_ATOMIC);
1412 sk_nocaps_add(newsk, NETIF_F_GSO_MASK);
1413 }
1414#endif
1415
1416 if (__inet_inherit_port(sk, newsk) < 0)
1417 goto put_and_exit;
1418 *own_req = inet_ehash_nolisten(newsk, req_to_sk(req_unhash));
1419 if (likely(*own_req)) {
1420 tcp_move_syn(newtp, req);
1421 ireq->ireq_opt = NULL;
1422 } else {
1423 newinet->inet_opt = NULL;
1424 }
1425 return newsk;
1426
1427exit_overflow:
1428 NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
1429exit_nonewsk:
1430 dst_release(dst);
1431exit:
1432 tcp_listendrop(sk);
1433 return NULL;
1434put_and_exit:
1435 newinet->inet_opt = NULL;
1436 inet_csk_prepare_forced_close(newsk);
1437 tcp_done(newsk);
1438 goto exit;
1439}
1440EXPORT_SYMBOL(tcp_v4_syn_recv_sock);
1441
1442static struct sock *tcp_v4_cookie_check(struct sock *sk, struct sk_buff *skb)
1443{
1444#ifdef CONFIG_SYN_COOKIES
1445 const struct tcphdr *th = tcp_hdr(skb);
1446
1447 if (!th->syn)
1448 sk = cookie_v4_check(sk, skb);
1449#endif
1450 return sk;
1451}
1452
1453/* The socket must have it's spinlock held when we get
1454 * here, unless it is a TCP_LISTEN socket.
1455 *
1456 * We have a potential double-lock case here, so even when
1457 * doing backlog processing we use the BH locking scheme.
1458 * This is because we cannot sleep with the original spinlock
1459 * held.
1460 */
1461int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
1462{
1463 struct sock *rsk;
1464
1465 if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
1466 struct dst_entry *dst = sk->sk_rx_dst;
1467
1468 sock_rps_save_rxhash(sk, skb);
1469 sk_mark_napi_id(sk, skb);
1470 if (dst) {
1471 if (inet_sk(sk)->rx_dst_ifindex != skb->skb_iif ||
1472 !dst->ops->check(dst, 0)) {
1473 dst_release(dst);
1474 sk->sk_rx_dst = NULL;
1475 }
1476 }
1477 tcp_rcv_established(sk, skb, tcp_hdr(skb));
1478 return 0;
1479 }
1480
1481 if (tcp_checksum_complete(skb))
1482 goto csum_err;
1483
1484 if (sk->sk_state == TCP_LISTEN) {
1485 struct sock *nsk = tcp_v4_cookie_check(sk, skb);
1486
1487 if (!nsk)
1488 goto discard;
1489 if (nsk != sk) {
1490 if (tcp_child_process(sk, nsk, skb)) {
1491 rsk = nsk;
1492 goto reset;
1493 }
1494 return 0;
1495 }
1496 } else
1497 sock_rps_save_rxhash(sk, skb);
1498
1499 if (tcp_rcv_state_process(sk, skb)) {
1500 rsk = sk;
1501 goto reset;
1502 }
1503 return 0;
1504
1505reset:
1506 tcp_v4_send_reset(rsk, skb);
1507discard:
1508 kfree_skb(skb);
1509 /* Be careful here. If this function gets more complicated and
1510 * gcc suffers from register pressure on the x86, sk (in %ebx)
1511 * might be destroyed here. This current version compiles correctly,
1512 * but you have been warned.
1513 */
1514 return 0;
1515
1516csum_err:
1517 TCP_INC_STATS(sock_net(sk), TCP_MIB_CSUMERRORS);
1518 TCP_INC_STATS(sock_net(sk), TCP_MIB_INERRS);
1519 goto discard;
1520}
1521EXPORT_SYMBOL(tcp_v4_do_rcv);
1522
1523int tcp_v4_early_demux(struct sk_buff *skb)
1524{
1525 const struct iphdr *iph;
1526 const struct tcphdr *th;
1527 struct sock *sk;
1528
1529 if (skb->pkt_type != PACKET_HOST)
1530 return 0;
1531
1532 if (!pskb_may_pull(skb, skb_transport_offset(skb) + sizeof(struct tcphdr)))
1533 return 0;
1534
1535 iph = ip_hdr(skb);
1536 th = tcp_hdr(skb);
1537
1538 if (th->doff < sizeof(struct tcphdr) / 4)
1539 return 0;
1540
1541 sk = __inet_lookup_established(dev_net(skb->dev), &tcp_hashinfo,
1542 iph->saddr, th->source,
1543 iph->daddr, ntohs(th->dest),
1544 skb->skb_iif, inet_sdif(skb));
1545 if (sk) {
1546 skb->sk = sk;
1547 skb->destructor = sock_edemux;
1548 if (sk_fullsock(sk)) {
1549 struct dst_entry *dst = READ_ONCE(sk->sk_rx_dst);
1550
1551 if (dst)
1552 dst = dst_check(dst, 0);
1553 if (dst &&
1554 inet_sk(sk)->rx_dst_ifindex == skb->skb_iif)
1555 skb_dst_set_noref(skb, dst);
1556 }
1557 }
1558 return 0;
1559}
1560
1561bool tcp_add_backlog(struct sock *sk, struct sk_buff *skb)
1562{
1563 u32 limit = sk->sk_rcvbuf + sk->sk_sndbuf;
1564
1565 /* Only socket owner can try to collapse/prune rx queues
1566 * to reduce memory overhead, so add a little headroom here.
1567 * Few sockets backlog are possibly concurrently non empty.
1568 */
1569 limit += 64*1024;
1570
1571 /* In case all data was pulled from skb frags (in __pskb_pull_tail()),
1572 * we can fix skb->truesize to its real value to avoid future drops.
1573 * This is valid because skb is not yet charged to the socket.
1574 * It has been noticed pure SACK packets were sometimes dropped
1575 * (if cooked by drivers without copybreak feature).
1576 */
1577 skb_condense(skb);
1578
1579 if (unlikely(sk_add_backlog(sk, skb, limit))) {
1580 bh_unlock_sock(sk);
1581 __NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPBACKLOGDROP);
1582 return true;
1583 }
1584 return false;
1585}
1586EXPORT_SYMBOL(tcp_add_backlog);
1587
1588int tcp_filter(struct sock *sk, struct sk_buff *skb)
1589{
1590 struct tcphdr *th = (struct tcphdr *)skb->data;
1591 unsigned int eaten = skb->len;
1592 int err;
1593
1594 err = sk_filter_trim_cap(sk, skb, th->doff * 4);
1595 if (!err) {
1596 eaten -= skb->len;
1597 TCP_SKB_CB(skb)->end_seq -= eaten;
1598 }
1599 return err;
1600}
1601EXPORT_SYMBOL(tcp_filter);
1602
1603static void tcp_v4_restore_cb(struct sk_buff *skb)
1604{
1605 memmove(IPCB(skb), &TCP_SKB_CB(skb)->header.h4,
1606 sizeof(struct inet_skb_parm));
1607}
1608
1609static void tcp_v4_fill_cb(struct sk_buff *skb, const struct iphdr *iph,
1610 const struct tcphdr *th)
1611{
1612 /* This is tricky : We move IPCB at its correct location into TCP_SKB_CB()
1613 * barrier() makes sure compiler wont play fool^Waliasing games.
1614 */
1615 memmove(&TCP_SKB_CB(skb)->header.h4, IPCB(skb),
1616 sizeof(struct inet_skb_parm));
1617 barrier();
1618
1619 TCP_SKB_CB(skb)->seq = ntohl(th->seq);
1620 TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
1621 skb->len - th->doff * 4);
1622 TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
1623 TCP_SKB_CB(skb)->tcp_flags = tcp_flag_byte(th);
1624 TCP_SKB_CB(skb)->tcp_tw_isn = 0;
1625 TCP_SKB_CB(skb)->ip_dsfield = ipv4_get_dsfield(iph);
1626 TCP_SKB_CB(skb)->sacked = 0;
1627 TCP_SKB_CB(skb)->has_rxtstamp =
1628 skb->tstamp || skb_hwtstamps(skb)->hwtstamp;
1629}
1630
1631/*
1632 * From tcp_input.c
1633 */
1634
1635int tcp_v4_rcv(struct sk_buff *skb)
1636{
1637 struct net *net = dev_net(skb->dev);
1638 int sdif = inet_sdif(skb);
1639 const struct iphdr *iph;
1640 const struct tcphdr *th;
1641 bool refcounted;
1642 struct sock *sk;
1643 int ret;
1644
1645 if (skb->pkt_type != PACKET_HOST)
1646 goto discard_it;
1647
1648 /* Count it even if it's bad */
1649 __TCP_INC_STATS(net, TCP_MIB_INSEGS);
1650
1651 if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
1652 goto discard_it;
1653
1654 th = (const struct tcphdr *)skb->data;
1655
1656 if (unlikely(th->doff < sizeof(struct tcphdr) / 4))
1657 goto bad_packet;
1658 if (!pskb_may_pull(skb, th->doff * 4))
1659 goto discard_it;
1660
1661 /* An explanation is required here, I think.
1662 * Packet length and doff are validated by header prediction,
1663 * provided case of th->doff==0 is eliminated.
1664 * So, we defer the checks. */
1665
1666 if (skb_checksum_init(skb, IPPROTO_TCP, inet_compute_pseudo))
1667 goto csum_error;
1668
1669 th = (const struct tcphdr *)skb->data;
1670 iph = ip_hdr(skb);
1671lookup:
1672 sk = __inet_lookup_skb(&tcp_hashinfo, skb, __tcp_hdrlen(th), th->source,
1673 th->dest, sdif, &refcounted);
1674 if (!sk)
1675 goto no_tcp_socket;
1676
1677process:
1678 if (sk->sk_state == TCP_TIME_WAIT)
1679 goto do_time_wait;
1680
1681 if (sk->sk_state == TCP_NEW_SYN_RECV) {
1682 struct request_sock *req = inet_reqsk(sk);
1683 bool req_stolen = false;
1684 struct sock *nsk;
1685
1686 sk = req->rsk_listener;
1687 if (unlikely(tcp_v4_inbound_md5_hash(sk, skb))) {
1688 sk_drops_add(sk, skb);
1689 reqsk_put(req);
1690 goto discard_it;
1691 }
1692 if (unlikely(sk->sk_state != TCP_LISTEN)) {
1693 inet_csk_reqsk_queue_drop_and_put(sk, req);
1694 goto lookup;
1695 }
1696 /* We own a reference on the listener, increase it again
1697 * as we might lose it too soon.
1698 */
1699 sock_hold(sk);
1700 refcounted = true;
1701 nsk = NULL;
1702 if (!tcp_filter(sk, skb)) {
1703 th = (const struct tcphdr *)skb->data;
1704 iph = ip_hdr(skb);
1705 tcp_v4_fill_cb(skb, iph, th);
1706 nsk = tcp_check_req(sk, skb, req, false, &req_stolen);
1707 }
1708 if (!nsk) {
1709 reqsk_put(req);
1710 if (req_stolen) {
1711 /* Another cpu got exclusive access to req
1712 * and created a full blown socket.
1713 * Try to feed this packet to this socket
1714 * instead of discarding it.
1715 */
1716 tcp_v4_restore_cb(skb);
1717 sock_put(sk);
1718 goto lookup;
1719 }
1720 goto discard_and_relse;
1721 }
1722 if (nsk == sk) {
1723 reqsk_put(req);
1724 tcp_v4_restore_cb(skb);
1725 } else if (tcp_child_process(sk, nsk, skb)) {
1726 tcp_v4_send_reset(nsk, skb);
1727 goto discard_and_relse;
1728 } else {
1729 sock_put(sk);
1730 return 0;
1731 }
1732 }
1733 if (unlikely(iph->ttl < inet_sk(sk)->min_ttl)) {
1734 __NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP);
1735 goto discard_and_relse;
1736 }
1737
1738 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
1739 goto discard_and_relse;
1740
1741 if (tcp_v4_inbound_md5_hash(sk, skb))
1742 goto discard_and_relse;
1743
1744 nf_reset(skb);
1745
1746 if (tcp_filter(sk, skb))
1747 goto discard_and_relse;
1748 th = (const struct tcphdr *)skb->data;
1749 iph = ip_hdr(skb);
1750 tcp_v4_fill_cb(skb, iph, th);
1751
1752 skb->dev = NULL;
1753
1754 if (sk->sk_state == TCP_LISTEN) {
1755 ret = tcp_v4_do_rcv(sk, skb);
1756 goto put_and_return;
1757 }
1758
1759 sk_incoming_cpu_update(sk);
1760
1761 bh_lock_sock_nested(sk);
1762 tcp_segs_in(tcp_sk(sk), skb);
1763 ret = 0;
1764 if (!sock_owned_by_user(sk)) {
1765 ret = tcp_v4_do_rcv(sk, skb);
1766 } else if (tcp_add_backlog(sk, skb)) {
1767 goto discard_and_relse;
1768 }
1769 bh_unlock_sock(sk);
1770
1771put_and_return:
1772 if (refcounted)
1773 sock_put(sk);
1774
1775 return ret;
1776
1777no_tcp_socket:
1778 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
1779 goto discard_it;
1780
1781 tcp_v4_fill_cb(skb, iph, th);
1782
1783 if (tcp_checksum_complete(skb)) {
1784csum_error:
1785 __TCP_INC_STATS(net, TCP_MIB_CSUMERRORS);
1786bad_packet:
1787 __TCP_INC_STATS(net, TCP_MIB_INERRS);
1788 } else {
1789 tcp_v4_send_reset(NULL, skb);
1790 }
1791
1792discard_it:
1793 /* Discard frame. */
1794 kfree_skb(skb);
1795 return 0;
1796
1797discard_and_relse:
1798 sk_drops_add(sk, skb);
1799 if (refcounted)
1800 sock_put(sk);
1801 goto discard_it;
1802
1803do_time_wait:
1804 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
1805 inet_twsk_put(inet_twsk(sk));
1806 goto discard_it;
1807 }
1808
1809 tcp_v4_fill_cb(skb, iph, th);
1810
1811 if (tcp_checksum_complete(skb)) {
1812 inet_twsk_put(inet_twsk(sk));
1813 goto csum_error;
1814 }
1815 switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) {
1816 case TCP_TW_SYN: {
1817 struct sock *sk2 = inet_lookup_listener(dev_net(skb->dev),
1818 &tcp_hashinfo, skb,
1819 __tcp_hdrlen(th),
1820 iph->saddr, th->source,
1821 iph->daddr, th->dest,
1822 inet_iif(skb),
1823 sdif);
1824 if (sk2) {
1825 inet_twsk_deschedule_put(inet_twsk(sk));
1826 sk = sk2;
1827 tcp_v4_restore_cb(skb);
1828 refcounted = false;
1829 goto process;
1830 }
1831 }
1832 /* to ACK */
1833 /* fall through */
1834 case TCP_TW_ACK:
1835 tcp_v4_timewait_ack(sk, skb);
1836 break;
1837 case TCP_TW_RST:
1838 tcp_v4_send_reset(sk, skb);
1839 inet_twsk_deschedule_put(inet_twsk(sk));
1840 goto discard_it;
1841 case TCP_TW_SUCCESS:;
1842 }
1843 goto discard_it;
1844}
1845
1846static struct timewait_sock_ops tcp_timewait_sock_ops = {
1847 .twsk_obj_size = sizeof(struct tcp_timewait_sock),
1848 .twsk_unique = tcp_twsk_unique,
1849 .twsk_destructor= tcp_twsk_destructor,
1850};
1851
1852void inet_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb)
1853{
1854 struct dst_entry *dst = skb_dst(skb);
1855
1856 if (dst && dst_hold_safe(dst)) {
1857 sk->sk_rx_dst = dst;
1858 inet_sk(sk)->rx_dst_ifindex = skb->skb_iif;
1859 }
1860}
1861EXPORT_SYMBOL(inet_sk_rx_dst_set);
1862
1863const struct inet_connection_sock_af_ops ipv4_specific = {
1864 .queue_xmit = ip_queue_xmit,
1865 .send_check = tcp_v4_send_check,
1866 .rebuild_header = inet_sk_rebuild_header,
1867 .sk_rx_dst_set = inet_sk_rx_dst_set,
1868 .conn_request = tcp_v4_conn_request,
1869 .syn_recv_sock = tcp_v4_syn_recv_sock,
1870 .net_header_len = sizeof(struct iphdr),
1871 .setsockopt = ip_setsockopt,
1872 .getsockopt = ip_getsockopt,
1873 .addr2sockaddr = inet_csk_addr2sockaddr,
1874 .sockaddr_len = sizeof(struct sockaddr_in),
1875#ifdef CONFIG_COMPAT
1876 .compat_setsockopt = compat_ip_setsockopt,
1877 .compat_getsockopt = compat_ip_getsockopt,
1878#endif
1879 .mtu_reduced = tcp_v4_mtu_reduced,
1880};
1881EXPORT_SYMBOL(ipv4_specific);
1882
1883#ifdef CONFIG_TCP_MD5SIG
1884static const struct tcp_sock_af_ops tcp_sock_ipv4_specific = {
1885 .md5_lookup = tcp_v4_md5_lookup,
1886 .calc_md5_hash = tcp_v4_md5_hash_skb,
1887 .md5_parse = tcp_v4_parse_md5_keys,
1888};
1889#endif
1890
1891/* NOTE: A lot of things set to zero explicitly by call to
1892 * sk_alloc() so need not be done here.
1893 */
1894static int tcp_v4_init_sock(struct sock *sk)
1895{
1896 struct inet_connection_sock *icsk = inet_csk(sk);
1897
1898 tcp_init_sock(sk);
1899
1900 icsk->icsk_af_ops = &ipv4_specific;
1901
1902#ifdef CONFIG_TCP_MD5SIG
1903 tcp_sk(sk)->af_specific = &tcp_sock_ipv4_specific;
1904#endif
1905
1906 return 0;
1907}
1908
1909void tcp_v4_destroy_sock(struct sock *sk)
1910{
1911 struct tcp_sock *tp = tcp_sk(sk);
1912
1913 trace_tcp_destroy_sock(sk);
1914
1915 tcp_clear_xmit_timers(sk);
1916
1917 tcp_cleanup_congestion_control(sk);
1918
1919 tcp_cleanup_ulp(sk);
1920
1921 /* Cleanup up the write buffer. */
1922 tcp_write_queue_purge(sk);
1923
1924 /* Check if we want to disable active TFO */
1925 tcp_fastopen_active_disable_ofo_check(sk);
1926
1927 /* Cleans up our, hopefully empty, out_of_order_queue. */
1928 skb_rbtree_purge(&tp->out_of_order_queue);
1929
1930#ifdef CONFIG_TCP_MD5SIG
1931 /* Clean up the MD5 key list, if any */
1932 if (tp->md5sig_info) {
1933 tcp_clear_md5_list(sk);
1934 kfree_rcu(rcu_dereference_protected(tp->md5sig_info, 1), rcu);
1935 tp->md5sig_info = NULL;
1936 }
1937#endif
1938
1939 /* Clean up a referenced TCP bind bucket. */
1940 if (inet_csk(sk)->icsk_bind_hash)
1941 inet_put_port(sk);
1942
1943 BUG_ON(tp->fastopen_rsk);
1944
1945 /* If socket is aborted during connect operation */
1946 tcp_free_fastopen_req(tp);
1947 tcp_fastopen_destroy_cipher(sk);
1948 tcp_saved_syn_free(tp);
1949
1950 sk_sockets_allocated_dec(sk);
1951}
1952EXPORT_SYMBOL(tcp_v4_destroy_sock);
1953
1954#ifdef CONFIG_PROC_FS
1955/* Proc filesystem TCP sock list dumping. */
1956
1957/*
1958 * Get next listener socket follow cur. If cur is NULL, get first socket
1959 * starting from bucket given in st->bucket; when st->bucket is zero the
1960 * very first socket in the hash table is returned.
1961 */
1962static void *listening_get_next(struct seq_file *seq, void *cur)
1963{
1964 struct tcp_iter_state *st = seq->private;
1965 struct net *net = seq_file_net(seq);
1966 struct inet_listen_hashbucket *ilb;
1967 struct sock *sk = cur;
1968
1969 if (!sk) {
1970get_head:
1971 ilb = &tcp_hashinfo.listening_hash[st->bucket];
1972 spin_lock(&ilb->lock);
1973 sk = sk_head(&ilb->head);
1974 st->offset = 0;
1975 goto get_sk;
1976 }
1977 ilb = &tcp_hashinfo.listening_hash[st->bucket];
1978 ++st->num;
1979 ++st->offset;
1980
1981 sk = sk_next(sk);
1982get_sk:
1983 sk_for_each_from(sk) {
1984 if (!net_eq(sock_net(sk), net))
1985 continue;
1986 if (sk->sk_family == st->family)
1987 return sk;
1988 }
1989 spin_unlock(&ilb->lock);
1990 st->offset = 0;
1991 if (++st->bucket < INET_LHTABLE_SIZE)
1992 goto get_head;
1993 return NULL;
1994}
1995
1996static void *listening_get_idx(struct seq_file *seq, loff_t *pos)
1997{
1998 struct tcp_iter_state *st = seq->private;
1999 void *rc;
2000
2001 st->bucket = 0;
2002 st->offset = 0;
2003 rc = listening_get_next(seq, NULL);
2004
2005 while (rc && *pos) {
2006 rc = listening_get_next(seq, rc);
2007 --*pos;
2008 }
2009 return rc;
2010}
2011
2012static inline bool empty_bucket(const struct tcp_iter_state *st)
2013{
2014 return hlist_nulls_empty(&tcp_hashinfo.ehash[st->bucket].chain);
2015}
2016
2017/*
2018 * Get first established socket starting from bucket given in st->bucket.
2019 * If st->bucket is zero, the very first socket in the hash is returned.
2020 */
2021static void *established_get_first(struct seq_file *seq)
2022{
2023 struct tcp_iter_state *st = seq->private;
2024 struct net *net = seq_file_net(seq);
2025 void *rc = NULL;
2026
2027 st->offset = 0;
2028 for (; st->bucket <= tcp_hashinfo.ehash_mask; ++st->bucket) {
2029 struct sock *sk;
2030 struct hlist_nulls_node *node;
2031 spinlock_t *lock = inet_ehash_lockp(&tcp_hashinfo, st->bucket);
2032
2033 /* Lockless fast path for the common case of empty buckets */
2034 if (empty_bucket(st))
2035 continue;
2036
2037 spin_lock_bh(lock);
2038 sk_nulls_for_each(sk, node, &tcp_hashinfo.ehash[st->bucket].chain) {
2039 if (sk->sk_family != st->family ||
2040 !net_eq(sock_net(sk), net)) {
2041 continue;
2042 }
2043 rc = sk;
2044 goto out;
2045 }
2046 spin_unlock_bh(lock);
2047 }
2048out:
2049 return rc;
2050}
2051
2052static void *established_get_next(struct seq_file *seq, void *cur)
2053{
2054 struct sock *sk = cur;
2055 struct hlist_nulls_node *node;
2056 struct tcp_iter_state *st = seq->private;
2057 struct net *net = seq_file_net(seq);
2058
2059 ++st->num;
2060 ++st->offset;
2061
2062 sk = sk_nulls_next(sk);
2063
2064 sk_nulls_for_each_from(sk, node) {
2065 if (sk->sk_family == st->family && net_eq(sock_net(sk), net))
2066 return sk;
2067 }
2068
2069 spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
2070 ++st->bucket;
2071 return established_get_first(seq);
2072}
2073
2074static void *established_get_idx(struct seq_file *seq, loff_t pos)
2075{
2076 struct tcp_iter_state *st = seq->private;
2077 void *rc;
2078
2079 st->bucket = 0;
2080 rc = established_get_first(seq);
2081
2082 while (rc && pos) {
2083 rc = established_get_next(seq, rc);
2084 --pos;
2085 }
2086 return rc;
2087}
2088
2089static void *tcp_get_idx(struct seq_file *seq, loff_t pos)
2090{
2091 void *rc;
2092 struct tcp_iter_state *st = seq->private;
2093
2094 st->state = TCP_SEQ_STATE_LISTENING;
2095 rc = listening_get_idx(seq, &pos);
2096
2097 if (!rc) {
2098 st->state = TCP_SEQ_STATE_ESTABLISHED;
2099 rc = established_get_idx(seq, pos);
2100 }
2101
2102 return rc;
2103}
2104
2105static void *tcp_seek_last_pos(struct seq_file *seq)
2106{
2107 struct tcp_iter_state *st = seq->private;
2108 int offset = st->offset;
2109 int orig_num = st->num;
2110 void *rc = NULL;
2111
2112 switch (st->state) {
2113 case TCP_SEQ_STATE_LISTENING:
2114 if (st->bucket >= INET_LHTABLE_SIZE)
2115 break;
2116 st->state = TCP_SEQ_STATE_LISTENING;
2117 rc = listening_get_next(seq, NULL);
2118 while (offset-- && rc)
2119 rc = listening_get_next(seq, rc);
2120 if (rc)
2121 break;
2122 st->bucket = 0;
2123 st->state = TCP_SEQ_STATE_ESTABLISHED;
2124 /* Fallthrough */
2125 case TCP_SEQ_STATE_ESTABLISHED:
2126 if (st->bucket > tcp_hashinfo.ehash_mask)
2127 break;
2128 rc = established_get_first(seq);
2129 while (offset-- && rc)
2130 rc = established_get_next(seq, rc);
2131 }
2132
2133 st->num = orig_num;
2134
2135 return rc;
2136}
2137
2138static void *tcp_seq_start(struct seq_file *seq, loff_t *pos)
2139{
2140 struct tcp_iter_state *st = seq->private;
2141 void *rc;
2142
2143 if (*pos && *pos == st->last_pos) {
2144 rc = tcp_seek_last_pos(seq);
2145 if (rc)
2146 goto out;
2147 }
2148
2149 st->state = TCP_SEQ_STATE_LISTENING;
2150 st->num = 0;
2151 st->bucket = 0;
2152 st->offset = 0;
2153 rc = *pos ? tcp_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
2154
2155out:
2156 st->last_pos = *pos;
2157 return rc;
2158}
2159
2160static void *tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2161{
2162 struct tcp_iter_state *st = seq->private;
2163 void *rc = NULL;
2164
2165 if (v == SEQ_START_TOKEN) {
2166 rc = tcp_get_idx(seq, 0);
2167 goto out;
2168 }
2169
2170 switch (st->state) {
2171 case TCP_SEQ_STATE_LISTENING:
2172 rc = listening_get_next(seq, v);
2173 if (!rc) {
2174 st->state = TCP_SEQ_STATE_ESTABLISHED;
2175 st->bucket = 0;
2176 st->offset = 0;
2177 rc = established_get_first(seq);
2178 }
2179 break;
2180 case TCP_SEQ_STATE_ESTABLISHED:
2181 rc = established_get_next(seq, v);
2182 break;
2183 }
2184out:
2185 ++*pos;
2186 st->last_pos = *pos;
2187 return rc;
2188}
2189
2190static void tcp_seq_stop(struct seq_file *seq, void *v)
2191{
2192 struct tcp_iter_state *st = seq->private;
2193
2194 switch (st->state) {
2195 case TCP_SEQ_STATE_LISTENING:
2196 if (v != SEQ_START_TOKEN)
2197 spin_unlock(&tcp_hashinfo.listening_hash[st->bucket].lock);
2198 break;
2199 case TCP_SEQ_STATE_ESTABLISHED:
2200 if (v)
2201 spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
2202 break;
2203 }
2204}
2205
2206int tcp_seq_open(struct inode *inode, struct file *file)
2207{
2208 struct tcp_seq_afinfo *afinfo = PDE_DATA(inode);
2209 struct tcp_iter_state *s;
2210 int err;
2211
2212 err = seq_open_net(inode, file, &afinfo->seq_ops,
2213 sizeof(struct tcp_iter_state));
2214 if (err < 0)
2215 return err;
2216
2217 s = ((struct seq_file *)file->private_data)->private;
2218 s->family = afinfo->family;
2219 s->last_pos = 0;
2220 return 0;
2221}
2222EXPORT_SYMBOL(tcp_seq_open);
2223
2224int tcp_proc_register(struct net *net, struct tcp_seq_afinfo *afinfo)
2225{
2226 int rc = 0;
2227 struct proc_dir_entry *p;
2228
2229 afinfo->seq_ops.start = tcp_seq_start;
2230 afinfo->seq_ops.next = tcp_seq_next;
2231 afinfo->seq_ops.stop = tcp_seq_stop;
2232
2233 p = proc_create_data(afinfo->name, 0444, net->proc_net,
2234 afinfo->seq_fops, afinfo);
2235 if (!p)
2236 rc = -ENOMEM;
2237 return rc;
2238}
2239EXPORT_SYMBOL(tcp_proc_register);
2240
2241void tcp_proc_unregister(struct net *net, struct tcp_seq_afinfo *afinfo)
2242{
2243 remove_proc_entry(afinfo->name, net->proc_net);
2244}
2245EXPORT_SYMBOL(tcp_proc_unregister);
2246
2247static void get_openreq4(const struct request_sock *req,
2248 struct seq_file *f, int i)
2249{
2250 const struct inet_request_sock *ireq = inet_rsk(req);
2251 long delta = req->rsk_timer.expires - jiffies;
2252
2253 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2254 " %02X %08X:%08X %02X:%08lX %08X %5u %8d %u %d %pK",
2255 i,
2256 ireq->ir_loc_addr,
2257 ireq->ir_num,
2258 ireq->ir_rmt_addr,
2259 ntohs(ireq->ir_rmt_port),
2260 TCP_SYN_RECV,
2261 0, 0, /* could print option size, but that is af dependent. */
2262 1, /* timers active (only the expire timer) */
2263 jiffies_delta_to_clock_t(delta),
2264 req->num_timeout,
2265 from_kuid_munged(seq_user_ns(f),
2266 sock_i_uid(req->rsk_listener)),
2267 0, /* non standard timer */
2268 0, /* open_requests have no inode */
2269 0,
2270 req);
2271}
2272
2273static void get_tcp4_sock(struct sock *sk, struct seq_file *f, int i)
2274{
2275 int timer_active;
2276 unsigned long timer_expires;
2277 const struct tcp_sock *tp = tcp_sk(sk);
2278 const struct inet_connection_sock *icsk = inet_csk(sk);
2279 const struct inet_sock *inet = inet_sk(sk);
2280 const struct fastopen_queue *fastopenq = &icsk->icsk_accept_queue.fastopenq;
2281 __be32 dest = inet->inet_daddr;
2282 __be32 src = inet->inet_rcv_saddr;
2283 __u16 destp = ntohs(inet->inet_dport);
2284 __u16 srcp = ntohs(inet->inet_sport);
2285 int rx_queue;
2286 int state;
2287
2288 if (icsk->icsk_pending == ICSK_TIME_RETRANS ||
2289 icsk->icsk_pending == ICSK_TIME_REO_TIMEOUT ||
2290 icsk->icsk_pending == ICSK_TIME_LOSS_PROBE) {
2291 timer_active = 1;
2292 timer_expires = icsk->icsk_timeout;
2293 } else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
2294 timer_active = 4;
2295 timer_expires = icsk->icsk_timeout;
2296 } else if (timer_pending(&sk->sk_timer)) {
2297 timer_active = 2;
2298 timer_expires = sk->sk_timer.expires;
2299 } else {
2300 timer_active = 0;
2301 timer_expires = jiffies;
2302 }
2303
2304 state = inet_sk_state_load(sk);
2305 if (state == TCP_LISTEN)
2306 rx_queue = sk->sk_ack_backlog;
2307 else
2308 /* Because we don't lock the socket,
2309 * we might find a transient negative value.
2310 */
2311 rx_queue = max_t(int, tp->rcv_nxt - tp->copied_seq, 0);
2312
2313 seq_printf(f, "%4d: %08X:%04X %08X:%04X %02X %08X:%08X %02X:%08lX "
2314 "%08X %5u %8d %lu %d %pK %lu %lu %u %u %d",
2315 i, src, srcp, dest, destp, state,
2316 tp->write_seq - tp->snd_una,
2317 rx_queue,
2318 timer_active,
2319 jiffies_delta_to_clock_t(timer_expires - jiffies),
2320 icsk->icsk_retransmits,
2321 from_kuid_munged(seq_user_ns(f), sock_i_uid(sk)),
2322 icsk->icsk_probes_out,
2323 sock_i_ino(sk),
2324 refcount_read(&sk->sk_refcnt), sk,
2325 jiffies_to_clock_t(icsk->icsk_rto),
2326 jiffies_to_clock_t(icsk->icsk_ack.ato),
2327 (icsk->icsk_ack.quick << 1) | icsk->icsk_ack.pingpong,
2328 tp->snd_cwnd,
2329 state == TCP_LISTEN ?
2330 fastopenq->max_qlen :
2331 (tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh));
2332}
2333
2334static void get_timewait4_sock(const struct inet_timewait_sock *tw,
2335 struct seq_file *f, int i)
2336{
2337 long delta = tw->tw_timer.expires - jiffies;
2338 __be32 dest, src;
2339 __u16 destp, srcp;
2340
2341 dest = tw->tw_daddr;
2342 src = tw->tw_rcv_saddr;
2343 destp = ntohs(tw->tw_dport);
2344 srcp = ntohs(tw->tw_sport);
2345
2346 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2347 " %02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK",
2348 i, src, srcp, dest, destp, tw->tw_substate, 0, 0,
2349 3, jiffies_delta_to_clock_t(delta), 0, 0, 0, 0,
2350 refcount_read(&tw->tw_refcnt), tw);
2351}
2352
2353#define TMPSZ 150
2354
2355static int tcp4_seq_show(struct seq_file *seq, void *v)
2356{
2357 struct tcp_iter_state *st;
2358 struct sock *sk = v;
2359
2360 seq_setwidth(seq, TMPSZ - 1);
2361 if (v == SEQ_START_TOKEN) {
2362 seq_puts(seq, " sl local_address rem_address st tx_queue "
2363 "rx_queue tr tm->when retrnsmt uid timeout "
2364 "inode");
2365 goto out;
2366 }
2367 st = seq->private;
2368
2369 if (sk->sk_state == TCP_TIME_WAIT)
2370 get_timewait4_sock(v, seq, st->num);
2371 else if (sk->sk_state == TCP_NEW_SYN_RECV)
2372 get_openreq4(v, seq, st->num);
2373 else
2374 get_tcp4_sock(v, seq, st->num);
2375out:
2376 seq_pad(seq, '\n');
2377 return 0;
2378}
2379
2380static const struct file_operations tcp_afinfo_seq_fops = {
2381 .open = tcp_seq_open,
2382 .read = seq_read,
2383 .llseek = seq_lseek,
2384 .release = seq_release_net
2385};
2386
2387static struct tcp_seq_afinfo tcp4_seq_afinfo = {
2388 .name = "tcp",
2389 .family = AF_INET,
2390 .seq_fops = &tcp_afinfo_seq_fops,
2391 .seq_ops = {
2392 .show = tcp4_seq_show,
2393 },
2394};
2395
2396static int __net_init tcp4_proc_init_net(struct net *net)
2397{
2398 return tcp_proc_register(net, &tcp4_seq_afinfo);
2399}
2400
2401static void __net_exit tcp4_proc_exit_net(struct net *net)
2402{
2403 tcp_proc_unregister(net, &tcp4_seq_afinfo);
2404}
2405
2406static struct pernet_operations tcp4_net_ops = {
2407 .init = tcp4_proc_init_net,
2408 .exit = tcp4_proc_exit_net,
2409};
2410
2411int __init tcp4_proc_init(void)
2412{
2413 return register_pernet_subsys(&tcp4_net_ops);
2414}
2415
2416void tcp4_proc_exit(void)
2417{
2418 unregister_pernet_subsys(&tcp4_net_ops);
2419}
2420#endif /* CONFIG_PROC_FS */
2421
2422struct proto tcp_prot = {
2423 .name = "TCP",
2424 .owner = THIS_MODULE,
2425 .close = tcp_close,
2426 .pre_connect = tcp_v4_pre_connect,
2427 .connect = tcp_v4_connect,
2428 .disconnect = tcp_disconnect,
2429 .accept = inet_csk_accept,
2430 .ioctl = tcp_ioctl,
2431 .init = tcp_v4_init_sock,
2432 .destroy = tcp_v4_destroy_sock,
2433 .shutdown = tcp_shutdown,
2434 .setsockopt = tcp_setsockopt,
2435 .getsockopt = tcp_getsockopt,
2436 .keepalive = tcp_set_keepalive,
2437 .recvmsg = tcp_recvmsg,
2438 .sendmsg = tcp_sendmsg,
2439 .sendpage = tcp_sendpage,
2440 .backlog_rcv = tcp_v4_do_rcv,
2441 .release_cb = tcp_release_cb,
2442 .hash = inet_hash,
2443 .unhash = inet_unhash,
2444 .get_port = inet_csk_get_port,
2445 .enter_memory_pressure = tcp_enter_memory_pressure,
2446 .leave_memory_pressure = tcp_leave_memory_pressure,
2447 .stream_memory_free = tcp_stream_memory_free,
2448 .sockets_allocated = &tcp_sockets_allocated,
2449 .orphan_count = &tcp_orphan_count,
2450 .memory_allocated = &tcp_memory_allocated,
2451 .memory_pressure = &tcp_memory_pressure,
2452 .sysctl_mem = sysctl_tcp_mem,
2453 .sysctl_wmem_offset = offsetof(struct net, ipv4.sysctl_tcp_wmem),
2454 .sysctl_rmem_offset = offsetof(struct net, ipv4.sysctl_tcp_rmem),
2455 .max_header = MAX_TCP_HEADER,
2456 .obj_size = sizeof(struct tcp_sock),
2457 .slab_flags = SLAB_TYPESAFE_BY_RCU,
2458 .twsk_prot = &tcp_timewait_sock_ops,
2459 .rsk_prot = &tcp_request_sock_ops,
2460 .h.hashinfo = &tcp_hashinfo,
2461 .no_autobind = true,
2462#ifdef CONFIG_COMPAT
2463 .compat_setsockopt = compat_tcp_setsockopt,
2464 .compat_getsockopt = compat_tcp_getsockopt,
2465#endif
2466 .diag_destroy = tcp_abort,
2467};
2468EXPORT_SYMBOL(tcp_prot);
2469
2470static void __net_exit tcp_sk_exit(struct net *net)
2471{
2472 int cpu;
2473
2474 module_put(net->ipv4.tcp_congestion_control->owner);
2475
2476 for_each_possible_cpu(cpu)
2477 inet_ctl_sock_destroy(*per_cpu_ptr(net->ipv4.tcp_sk, cpu));
2478 free_percpu(net->ipv4.tcp_sk);
2479}
2480
2481static int __net_init tcp_sk_init(struct net *net)
2482{
2483 int res, cpu, cnt;
2484
2485 net->ipv4.tcp_sk = alloc_percpu(struct sock *);
2486 if (!net->ipv4.tcp_sk)
2487 return -ENOMEM;
2488
2489 for_each_possible_cpu(cpu) {
2490 struct sock *sk;
2491
2492 res = inet_ctl_sock_create(&sk, PF_INET, SOCK_RAW,
2493 IPPROTO_TCP, net);
2494 if (res)
2495 goto fail;
2496 sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
2497 *per_cpu_ptr(net->ipv4.tcp_sk, cpu) = sk;
2498 }
2499
2500 net->ipv4.sysctl_tcp_ecn = 2;
2501 net->ipv4.sysctl_tcp_ecn_fallback = 1;
2502
2503 net->ipv4.sysctl_tcp_base_mss = TCP_BASE_MSS;
2504 net->ipv4.sysctl_tcp_probe_threshold = TCP_PROBE_THRESHOLD;
2505 net->ipv4.sysctl_tcp_probe_interval = TCP_PROBE_INTERVAL;
2506
2507 net->ipv4.sysctl_tcp_keepalive_time = TCP_KEEPALIVE_TIME;
2508 net->ipv4.sysctl_tcp_keepalive_probes = TCP_KEEPALIVE_PROBES;
2509 net->ipv4.sysctl_tcp_keepalive_intvl = TCP_KEEPALIVE_INTVL;
2510
2511 net->ipv4.sysctl_tcp_syn_retries = TCP_SYN_RETRIES;
2512 net->ipv4.sysctl_tcp_synack_retries = TCP_SYNACK_RETRIES;
2513 net->ipv4.sysctl_tcp_syncookies = 1;
2514 net->ipv4.sysctl_tcp_reordering = TCP_FASTRETRANS_THRESH;
2515 net->ipv4.sysctl_tcp_retries1 = TCP_RETR1;
2516 net->ipv4.sysctl_tcp_retries2 = TCP_RETR2;
2517 net->ipv4.sysctl_tcp_orphan_retries = 0;
2518 net->ipv4.sysctl_tcp_fin_timeout = TCP_FIN_TIMEOUT;
2519 net->ipv4.sysctl_tcp_notsent_lowat = UINT_MAX;
2520 net->ipv4.sysctl_tcp_tw_reuse = 0;
2521
2522 cnt = tcp_hashinfo.ehash_mask + 1;
2523 net->ipv4.tcp_death_row.sysctl_max_tw_buckets = (cnt + 1) / 2;
2524 net->ipv4.tcp_death_row.hashinfo = &tcp_hashinfo;
2525
2526 net->ipv4.sysctl_max_syn_backlog = max(128, cnt / 256);
2527 net->ipv4.sysctl_tcp_sack = 1;
2528 net->ipv4.sysctl_tcp_window_scaling = 1;
2529 net->ipv4.sysctl_tcp_timestamps = 1;
2530 net->ipv4.sysctl_tcp_early_retrans = 3;
2531 net->ipv4.sysctl_tcp_recovery = TCP_RACK_LOSS_DETECTION;
2532 net->ipv4.sysctl_tcp_slow_start_after_idle = 1; /* By default, RFC2861 behavior. */
2533 net->ipv4.sysctl_tcp_retrans_collapse = 1;
2534 net->ipv4.sysctl_tcp_max_reordering = 300;
2535 net->ipv4.sysctl_tcp_dsack = 1;
2536 net->ipv4.sysctl_tcp_app_win = 31;
2537 net->ipv4.sysctl_tcp_adv_win_scale = 1;
2538 net->ipv4.sysctl_tcp_frto = 2;
2539 net->ipv4.sysctl_tcp_moderate_rcvbuf = 1;
2540 /* This limits the percentage of the congestion window which we
2541 * will allow a single TSO frame to consume. Building TSO frames
2542 * which are too large can cause TCP streams to be bursty.
2543 */
2544 net->ipv4.sysctl_tcp_tso_win_divisor = 3;
2545 /* Default TSQ limit of four TSO segments */
2546 net->ipv4.sysctl_tcp_limit_output_bytes = 262144;
2547 /* rfc5961 challenge ack rate limiting */
2548 net->ipv4.sysctl_tcp_challenge_ack_limit = 1000;
2549 net->ipv4.sysctl_tcp_min_tso_segs = 2;
2550 net->ipv4.sysctl_tcp_min_rtt_wlen = 300;
2551 net->ipv4.sysctl_tcp_autocorking = 1;
2552 net->ipv4.sysctl_tcp_invalid_ratelimit = HZ/2;
2553 net->ipv4.sysctl_tcp_pacing_ss_ratio = 200;
2554 net->ipv4.sysctl_tcp_pacing_ca_ratio = 120;
2555 if (net != &init_net) {
2556 memcpy(net->ipv4.sysctl_tcp_rmem,
2557 init_net.ipv4.sysctl_tcp_rmem,
2558 sizeof(init_net.ipv4.sysctl_tcp_rmem));
2559 memcpy(net->ipv4.sysctl_tcp_wmem,
2560 init_net.ipv4.sysctl_tcp_wmem,
2561 sizeof(init_net.ipv4.sysctl_tcp_wmem));
2562 }
2563 net->ipv4.sysctl_tcp_fastopen = TFO_CLIENT_ENABLE;
2564 spin_lock_init(&net->ipv4.tcp_fastopen_ctx_lock);
2565 net->ipv4.sysctl_tcp_fastopen_blackhole_timeout = 60 * 60;
2566 atomic_set(&net->ipv4.tfo_active_disable_times, 0);
2567
2568 /* Reno is always built in */
2569 if (!net_eq(net, &init_net) &&
2570 try_module_get(init_net.ipv4.tcp_congestion_control->owner))
2571 net->ipv4.tcp_congestion_control = init_net.ipv4.tcp_congestion_control;
2572 else
2573 net->ipv4.tcp_congestion_control = &tcp_reno;
2574
2575 return 0;
2576fail:
2577 tcp_sk_exit(net);
2578
2579 return res;
2580}
2581
2582static void __net_exit tcp_sk_exit_batch(struct list_head *net_exit_list)
2583{
2584 struct net *net;
2585
2586 inet_twsk_purge(&tcp_hashinfo, AF_INET);
2587
2588 list_for_each_entry(net, net_exit_list, exit_list)
2589 tcp_fastopen_ctx_destroy(net);
2590}
2591
2592static struct pernet_operations __net_initdata tcp_sk_ops = {
2593 .init = tcp_sk_init,
2594 .exit = tcp_sk_exit,
2595 .exit_batch = tcp_sk_exit_batch,
2596};
2597
2598void __init tcp_v4_init(void)
2599{
2600 if (register_pernet_subsys(&tcp_sk_ops))
2601 panic("Failed to create the TCP control socket.\n");
2602}