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