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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 = tcp_sk(sk)->mtu_info;
346 dst = inet_csk_update_pmtu(sk, mtu);
347 if (!dst)
348 return;
349
350 /* Something is about to be wrong... Remember soft error
351 * for the case, if this connection will not able to recover.
352 */
353 if (mtu < dst_mtu(dst) && ip_dont_fragment(sk, dst))
354 sk->sk_err_soft = EMSGSIZE;
355
356 mtu = dst_mtu(dst);
357
358 if (inet->pmtudisc != IP_PMTUDISC_DONT &&
359 ip_sk_accept_pmtu(sk) &&
360 inet_csk(sk)->icsk_pmtu_cookie > mtu) {
361 tcp_sync_mss(sk, mtu);
362
363 /* Resend the TCP packet because it's
364 * clear that the old packet has been
365 * dropped. This is the new "fast" path mtu
366 * discovery.
367 */
368 tcp_simple_retransmit(sk);
369 } /* else let the usual retransmit timer handle it */
370}
371EXPORT_SYMBOL(tcp_v4_mtu_reduced);
372
373static void do_redirect(struct sk_buff *skb, struct sock *sk)
374{
375 struct dst_entry *dst = __sk_dst_check(sk, 0);
376
377 if (dst)
378 dst->ops->redirect(dst, sk, skb);
379}
380
381
382/* handle ICMP messages on TCP_NEW_SYN_RECV request sockets */
383void tcp_req_err(struct sock *sk, u32 seq, bool abort)
384{
385 struct request_sock *req = inet_reqsk(sk);
386 struct net *net = sock_net(sk);
387
388 /* ICMPs are not backlogged, hence we cannot get
389 * an established socket here.
390 */
391 if (seq != tcp_rsk(req)->snt_isn) {
392 __NET_INC_STATS(net, LINUX_MIB_OUTOFWINDOWICMPS);
393 } else if (abort) {
394 /*
395 * Still in SYN_RECV, just remove it silently.
396 * There is no good way to pass the error to the newly
397 * created socket, and POSIX does not want network
398 * errors returned from accept().
399 */
400 inet_csk_reqsk_queue_drop(req->rsk_listener, req);
401 tcp_listendrop(req->rsk_listener);
402 }
403 reqsk_put(req);
404}
405EXPORT_SYMBOL(tcp_req_err);
406
407/* TCP-LD (RFC 6069) logic */
408void tcp_ld_RTO_revert(struct sock *sk, u32 seq)
409{
410 struct inet_connection_sock *icsk = inet_csk(sk);
411 struct tcp_sock *tp = tcp_sk(sk);
412 struct sk_buff *skb;
413 s32 remaining;
414 u32 delta_us;
415
416 if (sock_owned_by_user(sk))
417 return;
418
419 if (seq != tp->snd_una || !icsk->icsk_retransmits ||
420 !icsk->icsk_backoff)
421 return;
422
423 skb = tcp_rtx_queue_head(sk);
424 if (WARN_ON_ONCE(!skb))
425 return;
426
427 icsk->icsk_backoff--;
428 icsk->icsk_rto = tp->srtt_us ? __tcp_set_rto(tp) : TCP_TIMEOUT_INIT;
429 icsk->icsk_rto = inet_csk_rto_backoff(icsk, TCP_RTO_MAX);
430
431 tcp_mstamp_refresh(tp);
432 delta_us = (u32)(tp->tcp_mstamp - tcp_skb_timestamp_us(skb));
433 remaining = icsk->icsk_rto - usecs_to_jiffies(delta_us);
434
435 if (remaining > 0) {
436 inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
437 remaining, TCP_RTO_MAX);
438 } else {
439 /* RTO revert clocked out retransmission.
440 * Will retransmit now.
441 */
442 tcp_retransmit_timer(sk);
443 }
444}
445EXPORT_SYMBOL(tcp_ld_RTO_revert);
446
447/*
448 * This routine is called by the ICMP module when it gets some
449 * sort of error condition. If err < 0 then the socket should
450 * be closed and the error returned to the user. If err > 0
451 * it's just the icmp type << 8 | icmp code. After adjustment
452 * header points to the first 8 bytes of the tcp header. We need
453 * to find the appropriate port.
454 *
455 * The locking strategy used here is very "optimistic". When
456 * someone else accesses the socket the ICMP is just dropped
457 * and for some paths there is no check at all.
458 * A more general error queue to queue errors for later handling
459 * is probably better.
460 *
461 */
462
463int tcp_v4_err(struct sk_buff *skb, u32 info)
464{
465 const struct iphdr *iph = (const struct iphdr *)skb->data;
466 struct tcphdr *th = (struct tcphdr *)(skb->data + (iph->ihl << 2));
467 struct tcp_sock *tp;
468 struct inet_sock *inet;
469 const int type = icmp_hdr(skb)->type;
470 const int code = icmp_hdr(skb)->code;
471 struct sock *sk;
472 struct request_sock *fastopen;
473 u32 seq, snd_una;
474 int err;
475 struct net *net = dev_net(skb->dev);
476
477 sk = __inet_lookup_established(net, &tcp_hashinfo, iph->daddr,
478 th->dest, iph->saddr, ntohs(th->source),
479 inet_iif(skb), 0);
480 if (!sk) {
481 __ICMP_INC_STATS(net, ICMP_MIB_INERRORS);
482 return -ENOENT;
483 }
484 if (sk->sk_state == TCP_TIME_WAIT) {
485 inet_twsk_put(inet_twsk(sk));
486 return 0;
487 }
488 seq = ntohl(th->seq);
489 if (sk->sk_state == TCP_NEW_SYN_RECV) {
490 tcp_req_err(sk, seq, type == ICMP_PARAMETERPROB ||
491 type == ICMP_TIME_EXCEEDED ||
492 (type == ICMP_DEST_UNREACH &&
493 (code == ICMP_NET_UNREACH ||
494 code == ICMP_HOST_UNREACH)));
495 return 0;
496 }
497
498 bh_lock_sock(sk);
499 /* If too many ICMPs get dropped on busy
500 * servers this needs to be solved differently.
501 * We do take care of PMTU discovery (RFC1191) special case :
502 * we can receive locally generated ICMP messages while socket is held.
503 */
504 if (sock_owned_by_user(sk)) {
505 if (!(type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED))
506 __NET_INC_STATS(net, LINUX_MIB_LOCKDROPPEDICMPS);
507 }
508 if (sk->sk_state == TCP_CLOSE)
509 goto out;
510
511 if (unlikely(iph->ttl < inet_sk(sk)->min_ttl)) {
512 __NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP);
513 goto out;
514 }
515
516 tp = tcp_sk(sk);
517 /* XXX (TFO) - tp->snd_una should be ISN (tcp_create_openreq_child() */
518 fastopen = rcu_dereference(tp->fastopen_rsk);
519 snd_una = fastopen ? tcp_rsk(fastopen)->snt_isn : tp->snd_una;
520 if (sk->sk_state != TCP_LISTEN &&
521 !between(seq, snd_una, tp->snd_nxt)) {
522 __NET_INC_STATS(net, LINUX_MIB_OUTOFWINDOWICMPS);
523 goto out;
524 }
525
526 switch (type) {
527 case ICMP_REDIRECT:
528 if (!sock_owned_by_user(sk))
529 do_redirect(skb, sk);
530 goto out;
531 case ICMP_SOURCE_QUENCH:
532 /* Just silently ignore these. */
533 goto out;
534 case ICMP_PARAMETERPROB:
535 err = EPROTO;
536 break;
537 case ICMP_DEST_UNREACH:
538 if (code > NR_ICMP_UNREACH)
539 goto out;
540
541 if (code == ICMP_FRAG_NEEDED) { /* PMTU discovery (RFC1191) */
542 /* We are not interested in TCP_LISTEN and open_requests
543 * (SYN-ACKs send out by Linux are always <576bytes so
544 * they should go through unfragmented).
545 */
546 if (sk->sk_state == TCP_LISTEN)
547 goto out;
548
549 tp->mtu_info = info;
550 if (!sock_owned_by_user(sk)) {
551 tcp_v4_mtu_reduced(sk);
552 } else {
553 if (!test_and_set_bit(TCP_MTU_REDUCED_DEFERRED, &sk->sk_tsq_flags))
554 sock_hold(sk);
555 }
556 goto out;
557 }
558
559 err = icmp_err_convert[code].errno;
560 /* check if this ICMP message allows revert of backoff.
561 * (see RFC 6069)
562 */
563 if (!fastopen &&
564 (code == ICMP_NET_UNREACH || code == ICMP_HOST_UNREACH))
565 tcp_ld_RTO_revert(sk, seq);
566 break;
567 case ICMP_TIME_EXCEEDED:
568 err = EHOSTUNREACH;
569 break;
570 default:
571 goto out;
572 }
573
574 switch (sk->sk_state) {
575 case TCP_SYN_SENT:
576 case TCP_SYN_RECV:
577 /* Only in fast or simultaneous open. If a fast open socket is
578 * is already accepted it is treated as a connected one below.
579 */
580 if (fastopen && !fastopen->sk)
581 break;
582
583 ip_icmp_error(sk, skb, err, th->dest, info, (u8 *)th);
584
585 if (!sock_owned_by_user(sk)) {
586 sk->sk_err = err;
587
588 sk->sk_error_report(sk);
589
590 tcp_done(sk);
591 } else {
592 sk->sk_err_soft = err;
593 }
594 goto out;
595 }
596
597 /* If we've already connected we will keep trying
598 * until we time out, or the user gives up.
599 *
600 * rfc1122 4.2.3.9 allows to consider as hard errors
601 * only PROTO_UNREACH and PORT_UNREACH (well, FRAG_FAILED too,
602 * but it is obsoleted by pmtu discovery).
603 *
604 * Note, that in modern internet, where routing is unreliable
605 * and in each dark corner broken firewalls sit, sending random
606 * errors ordered by their masters even this two messages finally lose
607 * their original sense (even Linux sends invalid PORT_UNREACHs)
608 *
609 * Now we are in compliance with RFCs.
610 * --ANK (980905)
611 */
612
613 inet = inet_sk(sk);
614 if (!sock_owned_by_user(sk) && inet->recverr) {
615 sk->sk_err = err;
616 sk->sk_error_report(sk);
617 } else { /* Only an error on timeout */
618 sk->sk_err_soft = err;
619 }
620
621out:
622 bh_unlock_sock(sk);
623 sock_put(sk);
624 return 0;
625}
626
627void __tcp_v4_send_check(struct sk_buff *skb, __be32 saddr, __be32 daddr)
628{
629 struct tcphdr *th = tcp_hdr(skb);
630
631 th->check = ~tcp_v4_check(skb->len, saddr, daddr, 0);
632 skb->csum_start = skb_transport_header(skb) - skb->head;
633 skb->csum_offset = offsetof(struct tcphdr, check);
634}
635
636/* This routine computes an IPv4 TCP checksum. */
637void tcp_v4_send_check(struct sock *sk, struct sk_buff *skb)
638{
639 const struct inet_sock *inet = inet_sk(sk);
640
641 __tcp_v4_send_check(skb, inet->inet_saddr, inet->inet_daddr);
642}
643EXPORT_SYMBOL(tcp_v4_send_check);
644
645/*
646 * This routine will send an RST to the other tcp.
647 *
648 * Someone asks: why I NEVER use socket parameters (TOS, TTL etc.)
649 * for reset.
650 * Answer: if a packet caused RST, it is not for a socket
651 * existing in our system, if it is matched to a socket,
652 * it is just duplicate segment or bug in other side's TCP.
653 * So that we build reply only basing on parameters
654 * arrived with segment.
655 * Exception: precedence violation. We do not implement it in any case.
656 */
657
658static void tcp_v4_send_reset(const struct sock *sk, struct sk_buff *skb)
659{
660 const struct tcphdr *th = tcp_hdr(skb);
661 struct {
662 struct tcphdr th;
663#ifdef CONFIG_TCP_MD5SIG
664 __be32 opt[(TCPOLEN_MD5SIG_ALIGNED >> 2)];
665#endif
666 } rep;
667 struct ip_reply_arg arg;
668#ifdef CONFIG_TCP_MD5SIG
669 struct tcp_md5sig_key *key = NULL;
670 const __u8 *hash_location = NULL;
671 unsigned char newhash[16];
672 int genhash;
673 struct sock *sk1 = NULL;
674#endif
675 u64 transmit_time = 0;
676 struct sock *ctl_sk;
677 struct net *net;
678
679 /* Never send a reset in response to a reset. */
680 if (th->rst)
681 return;
682
683 /* If sk not NULL, it means we did a successful lookup and incoming
684 * route had to be correct. prequeue might have dropped our dst.
685 */
686 if (!sk && skb_rtable(skb)->rt_type != RTN_LOCAL)
687 return;
688
689 /* Swap the send and the receive. */
690 memset(&rep, 0, sizeof(rep));
691 rep.th.dest = th->source;
692 rep.th.source = th->dest;
693 rep.th.doff = sizeof(struct tcphdr) / 4;
694 rep.th.rst = 1;
695
696 if (th->ack) {
697 rep.th.seq = th->ack_seq;
698 } else {
699 rep.th.ack = 1;
700 rep.th.ack_seq = htonl(ntohl(th->seq) + th->syn + th->fin +
701 skb->len - (th->doff << 2));
702 }
703
704 memset(&arg, 0, sizeof(arg));
705 arg.iov[0].iov_base = (unsigned char *)&rep;
706 arg.iov[0].iov_len = sizeof(rep.th);
707
708 net = sk ? sock_net(sk) : dev_net(skb_dst(skb)->dev);
709#ifdef CONFIG_TCP_MD5SIG
710 rcu_read_lock();
711 hash_location = tcp_parse_md5sig_option(th);
712 if (sk && sk_fullsock(sk)) {
713 const union tcp_md5_addr *addr;
714 int l3index;
715
716 /* sdif set, means packet ingressed via a device
717 * in an L3 domain and inet_iif is set to it.
718 */
719 l3index = tcp_v4_sdif(skb) ? inet_iif(skb) : 0;
720 addr = (union tcp_md5_addr *)&ip_hdr(skb)->saddr;
721 key = tcp_md5_do_lookup(sk, l3index, addr, AF_INET);
722 } else if (hash_location) {
723 const union tcp_md5_addr *addr;
724 int sdif = tcp_v4_sdif(skb);
725 int dif = inet_iif(skb);
726 int l3index;
727
728 /*
729 * active side is lost. Try to find listening socket through
730 * source port, and then find md5 key through listening socket.
731 * we are not loose security here:
732 * Incoming packet is checked with md5 hash with finding key,
733 * no RST generated if md5 hash doesn't match.
734 */
735 sk1 = __inet_lookup_listener(net, &tcp_hashinfo, NULL, 0,
736 ip_hdr(skb)->saddr,
737 th->source, ip_hdr(skb)->daddr,
738 ntohs(th->source), dif, sdif);
739 /* don't send rst if it can't find key */
740 if (!sk1)
741 goto out;
742
743 /* sdif set, means packet ingressed via a device
744 * in an L3 domain and dif is set to it.
745 */
746 l3index = sdif ? dif : 0;
747 addr = (union tcp_md5_addr *)&ip_hdr(skb)->saddr;
748 key = tcp_md5_do_lookup(sk1, l3index, addr, AF_INET);
749 if (!key)
750 goto out;
751
752
753 genhash = tcp_v4_md5_hash_skb(newhash, key, NULL, skb);
754 if (genhash || memcmp(hash_location, newhash, 16) != 0)
755 goto out;
756
757 }
758
759 if (key) {
760 rep.opt[0] = htonl((TCPOPT_NOP << 24) |
761 (TCPOPT_NOP << 16) |
762 (TCPOPT_MD5SIG << 8) |
763 TCPOLEN_MD5SIG);
764 /* Update length and the length the header thinks exists */
765 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED;
766 rep.th.doff = arg.iov[0].iov_len / 4;
767
768 tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[1],
769 key, ip_hdr(skb)->saddr,
770 ip_hdr(skb)->daddr, &rep.th);
771 }
772#endif
773 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
774 ip_hdr(skb)->saddr, /* XXX */
775 arg.iov[0].iov_len, IPPROTO_TCP, 0);
776 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
777 arg.flags = (sk && inet_sk_transparent(sk)) ? IP_REPLY_ARG_NOSRCCHECK : 0;
778
779 /* When socket is gone, all binding information is lost.
780 * routing might fail in this case. No choice here, if we choose to force
781 * input interface, we will misroute in case of asymmetric route.
782 */
783 if (sk) {
784 arg.bound_dev_if = sk->sk_bound_dev_if;
785 if (sk_fullsock(sk))
786 trace_tcp_send_reset(sk, skb);
787 }
788
789 BUILD_BUG_ON(offsetof(struct sock, sk_bound_dev_if) !=
790 offsetof(struct inet_timewait_sock, tw_bound_dev_if));
791
792 arg.tos = ip_hdr(skb)->tos;
793 arg.uid = sock_net_uid(net, sk && sk_fullsock(sk) ? sk : NULL);
794 local_bh_disable();
795 ctl_sk = this_cpu_read(*net->ipv4.tcp_sk);
796 if (sk) {
797 ctl_sk->sk_mark = (sk->sk_state == TCP_TIME_WAIT) ?
798 inet_twsk(sk)->tw_mark : sk->sk_mark;
799 ctl_sk->sk_priority = (sk->sk_state == TCP_TIME_WAIT) ?
800 inet_twsk(sk)->tw_priority : sk->sk_priority;
801 transmit_time = tcp_transmit_time(sk);
802 }
803 ip_send_unicast_reply(ctl_sk,
804 skb, &TCP_SKB_CB(skb)->header.h4.opt,
805 ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
806 &arg, arg.iov[0].iov_len,
807 transmit_time);
808
809 ctl_sk->sk_mark = 0;
810 __TCP_INC_STATS(net, TCP_MIB_OUTSEGS);
811 __TCP_INC_STATS(net, TCP_MIB_OUTRSTS);
812 local_bh_enable();
813
814#ifdef CONFIG_TCP_MD5SIG
815out:
816 rcu_read_unlock();
817#endif
818}
819
820/* The code following below sending ACKs in SYN-RECV and TIME-WAIT states
821 outside socket context is ugly, certainly. What can I do?
822 */
823
824static void tcp_v4_send_ack(const struct sock *sk,
825 struct sk_buff *skb, u32 seq, u32 ack,
826 u32 win, u32 tsval, u32 tsecr, int oif,
827 struct tcp_md5sig_key *key,
828 int reply_flags, u8 tos)
829{
830 const struct tcphdr *th = tcp_hdr(skb);
831 struct {
832 struct tcphdr th;
833 __be32 opt[(TCPOLEN_TSTAMP_ALIGNED >> 2)
834#ifdef CONFIG_TCP_MD5SIG
835 + (TCPOLEN_MD5SIG_ALIGNED >> 2)
836#endif
837 ];
838 } rep;
839 struct net *net = sock_net(sk);
840 struct ip_reply_arg arg;
841 struct sock *ctl_sk;
842 u64 transmit_time;
843
844 memset(&rep.th, 0, sizeof(struct tcphdr));
845 memset(&arg, 0, sizeof(arg));
846
847 arg.iov[0].iov_base = (unsigned char *)&rep;
848 arg.iov[0].iov_len = sizeof(rep.th);
849 if (tsecr) {
850 rep.opt[0] = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
851 (TCPOPT_TIMESTAMP << 8) |
852 TCPOLEN_TIMESTAMP);
853 rep.opt[1] = htonl(tsval);
854 rep.opt[2] = htonl(tsecr);
855 arg.iov[0].iov_len += TCPOLEN_TSTAMP_ALIGNED;
856 }
857
858 /* Swap the send and the receive. */
859 rep.th.dest = th->source;
860 rep.th.source = th->dest;
861 rep.th.doff = arg.iov[0].iov_len / 4;
862 rep.th.seq = htonl(seq);
863 rep.th.ack_seq = htonl(ack);
864 rep.th.ack = 1;
865 rep.th.window = htons(win);
866
867#ifdef CONFIG_TCP_MD5SIG
868 if (key) {
869 int offset = (tsecr) ? 3 : 0;
870
871 rep.opt[offset++] = htonl((TCPOPT_NOP << 24) |
872 (TCPOPT_NOP << 16) |
873 (TCPOPT_MD5SIG << 8) |
874 TCPOLEN_MD5SIG);
875 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED;
876 rep.th.doff = arg.iov[0].iov_len/4;
877
878 tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[offset],
879 key, ip_hdr(skb)->saddr,
880 ip_hdr(skb)->daddr, &rep.th);
881 }
882#endif
883 arg.flags = reply_flags;
884 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
885 ip_hdr(skb)->saddr, /* XXX */
886 arg.iov[0].iov_len, IPPROTO_TCP, 0);
887 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
888 if (oif)
889 arg.bound_dev_if = oif;
890 arg.tos = tos;
891 arg.uid = sock_net_uid(net, sk_fullsock(sk) ? sk : NULL);
892 local_bh_disable();
893 ctl_sk = this_cpu_read(*net->ipv4.tcp_sk);
894 ctl_sk->sk_mark = (sk->sk_state == TCP_TIME_WAIT) ?
895 inet_twsk(sk)->tw_mark : sk->sk_mark;
896 ctl_sk->sk_priority = (sk->sk_state == TCP_TIME_WAIT) ?
897 inet_twsk(sk)->tw_priority : sk->sk_priority;
898 transmit_time = tcp_transmit_time(sk);
899 ip_send_unicast_reply(ctl_sk,
900 skb, &TCP_SKB_CB(skb)->header.h4.opt,
901 ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
902 &arg, arg.iov[0].iov_len,
903 transmit_time);
904
905 ctl_sk->sk_mark = 0;
906 __TCP_INC_STATS(net, TCP_MIB_OUTSEGS);
907 local_bh_enable();
908}
909
910static void tcp_v4_timewait_ack(struct sock *sk, struct sk_buff *skb)
911{
912 struct inet_timewait_sock *tw = inet_twsk(sk);
913 struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
914
915 tcp_v4_send_ack(sk, skb,
916 tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
917 tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
918 tcp_time_stamp_raw() + tcptw->tw_ts_offset,
919 tcptw->tw_ts_recent,
920 tw->tw_bound_dev_if,
921 tcp_twsk_md5_key(tcptw),
922 tw->tw_transparent ? IP_REPLY_ARG_NOSRCCHECK : 0,
923 tw->tw_tos
924 );
925
926 inet_twsk_put(tw);
927}
928
929static void tcp_v4_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb,
930 struct request_sock *req)
931{
932 const union tcp_md5_addr *addr;
933 int l3index;
934
935 /* sk->sk_state == TCP_LISTEN -> for regular TCP_SYN_RECV
936 * sk->sk_state == TCP_SYN_RECV -> for Fast Open.
937 */
938 u32 seq = (sk->sk_state == TCP_LISTEN) ? tcp_rsk(req)->snt_isn + 1 :
939 tcp_sk(sk)->snd_nxt;
940
941 /* RFC 7323 2.3
942 * The window field (SEG.WND) of every outgoing segment, with the
943 * exception of <SYN> segments, MUST be right-shifted by
944 * Rcv.Wind.Shift bits:
945 */
946 addr = (union tcp_md5_addr *)&ip_hdr(skb)->saddr;
947 l3index = tcp_v4_sdif(skb) ? inet_iif(skb) : 0;
948 tcp_v4_send_ack(sk, skb, seq,
949 tcp_rsk(req)->rcv_nxt,
950 req->rsk_rcv_wnd >> inet_rsk(req)->rcv_wscale,
951 tcp_time_stamp_raw() + tcp_rsk(req)->ts_off,
952 req->ts_recent,
953 0,
954 tcp_md5_do_lookup(sk, l3index, addr, AF_INET),
955 inet_rsk(req)->no_srccheck ? IP_REPLY_ARG_NOSRCCHECK : 0,
956 ip_hdr(skb)->tos);
957}
958
959/*
960 * Send a SYN-ACK after having received a SYN.
961 * This still operates on a request_sock only, not on a big
962 * socket.
963 */
964static int tcp_v4_send_synack(const struct sock *sk, struct dst_entry *dst,
965 struct flowi *fl,
966 struct request_sock *req,
967 struct tcp_fastopen_cookie *foc,
968 enum tcp_synack_type synack_type)
969{
970 const struct inet_request_sock *ireq = inet_rsk(req);
971 struct flowi4 fl4;
972 int err = -1;
973 struct sk_buff *skb;
974
975 /* First, grab a route. */
976 if (!dst && (dst = inet_csk_route_req(sk, &fl4, req)) == NULL)
977 return -1;
978
979 skb = tcp_make_synack(sk, dst, req, foc, synack_type);
980
981 if (skb) {
982 __tcp_v4_send_check(skb, ireq->ir_loc_addr, ireq->ir_rmt_addr);
983
984 rcu_read_lock();
985 err = ip_build_and_send_pkt(skb, sk, ireq->ir_loc_addr,
986 ireq->ir_rmt_addr,
987 rcu_dereference(ireq->ireq_opt));
988 rcu_read_unlock();
989 err = net_xmit_eval(err);
990 }
991
992 return err;
993}
994
995/*
996 * IPv4 request_sock destructor.
997 */
998static void tcp_v4_reqsk_destructor(struct request_sock *req)
999{
1000 kfree(rcu_dereference_protected(inet_rsk(req)->ireq_opt, 1));
1001}
1002
1003#ifdef CONFIG_TCP_MD5SIG
1004/*
1005 * RFC2385 MD5 checksumming requires a mapping of
1006 * IP address->MD5 Key.
1007 * We need to maintain these in the sk structure.
1008 */
1009
1010DEFINE_STATIC_KEY_FALSE(tcp_md5_needed);
1011EXPORT_SYMBOL(tcp_md5_needed);
1012
1013/* Find the Key structure for an address. */
1014struct tcp_md5sig_key *__tcp_md5_do_lookup(const struct sock *sk, int l3index,
1015 const union tcp_md5_addr *addr,
1016 int family)
1017{
1018 const struct tcp_sock *tp = tcp_sk(sk);
1019 struct tcp_md5sig_key *key;
1020 const struct tcp_md5sig_info *md5sig;
1021 __be32 mask;
1022 struct tcp_md5sig_key *best_match = NULL;
1023 bool match;
1024
1025 /* caller either holds rcu_read_lock() or socket lock */
1026 md5sig = rcu_dereference_check(tp->md5sig_info,
1027 lockdep_sock_is_held(sk));
1028 if (!md5sig)
1029 return NULL;
1030
1031 hlist_for_each_entry_rcu(key, &md5sig->head, node,
1032 lockdep_sock_is_held(sk)) {
1033 if (key->family != family)
1034 continue;
1035 if (key->l3index && key->l3index != l3index)
1036 continue;
1037 if (family == AF_INET) {
1038 mask = inet_make_mask(key->prefixlen);
1039 match = (key->addr.a4.s_addr & mask) ==
1040 (addr->a4.s_addr & mask);
1041#if IS_ENABLED(CONFIG_IPV6)
1042 } else if (family == AF_INET6) {
1043 match = ipv6_prefix_equal(&key->addr.a6, &addr->a6,
1044 key->prefixlen);
1045#endif
1046 } else {
1047 match = false;
1048 }
1049
1050 if (match && (!best_match ||
1051 key->prefixlen > best_match->prefixlen))
1052 best_match = key;
1053 }
1054 return best_match;
1055}
1056EXPORT_SYMBOL(__tcp_md5_do_lookup);
1057
1058static struct tcp_md5sig_key *tcp_md5_do_lookup_exact(const struct sock *sk,
1059 const union tcp_md5_addr *addr,
1060 int family, u8 prefixlen,
1061 int l3index)
1062{
1063 const struct tcp_sock *tp = tcp_sk(sk);
1064 struct tcp_md5sig_key *key;
1065 unsigned int size = sizeof(struct in_addr);
1066 const struct tcp_md5sig_info *md5sig;
1067
1068 /* caller either holds rcu_read_lock() or socket lock */
1069 md5sig = rcu_dereference_check(tp->md5sig_info,
1070 lockdep_sock_is_held(sk));
1071 if (!md5sig)
1072 return NULL;
1073#if IS_ENABLED(CONFIG_IPV6)
1074 if (family == AF_INET6)
1075 size = sizeof(struct in6_addr);
1076#endif
1077 hlist_for_each_entry_rcu(key, &md5sig->head, node,
1078 lockdep_sock_is_held(sk)) {
1079 if (key->family != family)
1080 continue;
1081 if (key->l3index && key->l3index != l3index)
1082 continue;
1083 if (!memcmp(&key->addr, addr, size) &&
1084 key->prefixlen == prefixlen)
1085 return key;
1086 }
1087 return NULL;
1088}
1089
1090struct tcp_md5sig_key *tcp_v4_md5_lookup(const struct sock *sk,
1091 const struct sock *addr_sk)
1092{
1093 const union tcp_md5_addr *addr;
1094 int l3index;
1095
1096 l3index = l3mdev_master_ifindex_by_index(sock_net(sk),
1097 addr_sk->sk_bound_dev_if);
1098 addr = (const union tcp_md5_addr *)&addr_sk->sk_daddr;
1099 return tcp_md5_do_lookup(sk, l3index, addr, AF_INET);
1100}
1101EXPORT_SYMBOL(tcp_v4_md5_lookup);
1102
1103/* This can be called on a newly created socket, from other files */
1104int tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr,
1105 int family, u8 prefixlen, int l3index,
1106 const u8 *newkey, u8 newkeylen, gfp_t gfp)
1107{
1108 /* Add Key to the list */
1109 struct tcp_md5sig_key *key;
1110 struct tcp_sock *tp = tcp_sk(sk);
1111 struct tcp_md5sig_info *md5sig;
1112
1113 key = tcp_md5_do_lookup_exact(sk, addr, family, prefixlen, l3index);
1114 if (key) {
1115 /* Pre-existing entry - just update that one.
1116 * Note that the key might be used concurrently.
1117 * data_race() is telling kcsan that we do not care of
1118 * key mismatches, since changing MD5 key on live flows
1119 * can lead to packet drops.
1120 */
1121 data_race(memcpy(key->key, newkey, newkeylen));
1122
1123 /* Pairs with READ_ONCE() in tcp_md5_hash_key().
1124 * Also note that a reader could catch new key->keylen value
1125 * but old key->key[], this is the reason we use __GFP_ZERO
1126 * at sock_kmalloc() time below these lines.
1127 */
1128 WRITE_ONCE(key->keylen, newkeylen);
1129
1130 return 0;
1131 }
1132
1133 md5sig = rcu_dereference_protected(tp->md5sig_info,
1134 lockdep_sock_is_held(sk));
1135 if (!md5sig) {
1136 md5sig = kmalloc(sizeof(*md5sig), gfp);
1137 if (!md5sig)
1138 return -ENOMEM;
1139
1140 sk_nocaps_add(sk, NETIF_F_GSO_MASK);
1141 INIT_HLIST_HEAD(&md5sig->head);
1142 rcu_assign_pointer(tp->md5sig_info, md5sig);
1143 }
1144
1145 key = sock_kmalloc(sk, sizeof(*key), gfp | __GFP_ZERO);
1146 if (!key)
1147 return -ENOMEM;
1148 if (!tcp_alloc_md5sig_pool()) {
1149 sock_kfree_s(sk, key, sizeof(*key));
1150 return -ENOMEM;
1151 }
1152
1153 memcpy(key->key, newkey, newkeylen);
1154 key->keylen = newkeylen;
1155 key->family = family;
1156 key->prefixlen = prefixlen;
1157 key->l3index = l3index;
1158 memcpy(&key->addr, addr,
1159 (family == AF_INET6) ? sizeof(struct in6_addr) :
1160 sizeof(struct in_addr));
1161 hlist_add_head_rcu(&key->node, &md5sig->head);
1162 return 0;
1163}
1164EXPORT_SYMBOL(tcp_md5_do_add);
1165
1166int tcp_md5_do_del(struct sock *sk, const union tcp_md5_addr *addr, int family,
1167 u8 prefixlen, int l3index)
1168{
1169 struct tcp_md5sig_key *key;
1170
1171 key = tcp_md5_do_lookup_exact(sk, addr, family, prefixlen, l3index);
1172 if (!key)
1173 return -ENOENT;
1174 hlist_del_rcu(&key->node);
1175 atomic_sub(sizeof(*key), &sk->sk_omem_alloc);
1176 kfree_rcu(key, rcu);
1177 return 0;
1178}
1179EXPORT_SYMBOL(tcp_md5_do_del);
1180
1181static void tcp_clear_md5_list(struct sock *sk)
1182{
1183 struct tcp_sock *tp = tcp_sk(sk);
1184 struct tcp_md5sig_key *key;
1185 struct hlist_node *n;
1186 struct tcp_md5sig_info *md5sig;
1187
1188 md5sig = rcu_dereference_protected(tp->md5sig_info, 1);
1189
1190 hlist_for_each_entry_safe(key, n, &md5sig->head, node) {
1191 hlist_del_rcu(&key->node);
1192 atomic_sub(sizeof(*key), &sk->sk_omem_alloc);
1193 kfree_rcu(key, rcu);
1194 }
1195}
1196
1197static int tcp_v4_parse_md5_keys(struct sock *sk, int optname,
1198 sockptr_t optval, int optlen)
1199{
1200 struct tcp_md5sig cmd;
1201 struct sockaddr_in *sin = (struct sockaddr_in *)&cmd.tcpm_addr;
1202 const union tcp_md5_addr *addr;
1203 u8 prefixlen = 32;
1204 int l3index = 0;
1205
1206 if (optlen < sizeof(cmd))
1207 return -EINVAL;
1208
1209 if (copy_from_sockptr(&cmd, optval, sizeof(cmd)))
1210 return -EFAULT;
1211
1212 if (sin->sin_family != AF_INET)
1213 return -EINVAL;
1214
1215 if (optname == TCP_MD5SIG_EXT &&
1216 cmd.tcpm_flags & TCP_MD5SIG_FLAG_PREFIX) {
1217 prefixlen = cmd.tcpm_prefixlen;
1218 if (prefixlen > 32)
1219 return -EINVAL;
1220 }
1221
1222 if (optname == TCP_MD5SIG_EXT &&
1223 cmd.tcpm_flags & TCP_MD5SIG_FLAG_IFINDEX) {
1224 struct net_device *dev;
1225
1226 rcu_read_lock();
1227 dev = dev_get_by_index_rcu(sock_net(sk), cmd.tcpm_ifindex);
1228 if (dev && netif_is_l3_master(dev))
1229 l3index = dev->ifindex;
1230
1231 rcu_read_unlock();
1232
1233 /* ok to reference set/not set outside of rcu;
1234 * right now device MUST be an L3 master
1235 */
1236 if (!dev || !l3index)
1237 return -EINVAL;
1238 }
1239
1240 addr = (union tcp_md5_addr *)&sin->sin_addr.s_addr;
1241
1242 if (!cmd.tcpm_keylen)
1243 return tcp_md5_do_del(sk, addr, AF_INET, prefixlen, l3index);
1244
1245 if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN)
1246 return -EINVAL;
1247
1248 return tcp_md5_do_add(sk, addr, AF_INET, prefixlen, l3index,
1249 cmd.tcpm_key, cmd.tcpm_keylen, GFP_KERNEL);
1250}
1251
1252static int tcp_v4_md5_hash_headers(struct tcp_md5sig_pool *hp,
1253 __be32 daddr, __be32 saddr,
1254 const struct tcphdr *th, int nbytes)
1255{
1256 struct tcp4_pseudohdr *bp;
1257 struct scatterlist sg;
1258 struct tcphdr *_th;
1259
1260 bp = hp->scratch;
1261 bp->saddr = saddr;
1262 bp->daddr = daddr;
1263 bp->pad = 0;
1264 bp->protocol = IPPROTO_TCP;
1265 bp->len = cpu_to_be16(nbytes);
1266
1267 _th = (struct tcphdr *)(bp + 1);
1268 memcpy(_th, th, sizeof(*th));
1269 _th->check = 0;
1270
1271 sg_init_one(&sg, bp, sizeof(*bp) + sizeof(*th));
1272 ahash_request_set_crypt(hp->md5_req, &sg, NULL,
1273 sizeof(*bp) + sizeof(*th));
1274 return crypto_ahash_update(hp->md5_req);
1275}
1276
1277static int tcp_v4_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key,
1278 __be32 daddr, __be32 saddr, const struct tcphdr *th)
1279{
1280 struct tcp_md5sig_pool *hp;
1281 struct ahash_request *req;
1282
1283 hp = tcp_get_md5sig_pool();
1284 if (!hp)
1285 goto clear_hash_noput;
1286 req = hp->md5_req;
1287
1288 if (crypto_ahash_init(req))
1289 goto clear_hash;
1290 if (tcp_v4_md5_hash_headers(hp, daddr, saddr, th, th->doff << 2))
1291 goto clear_hash;
1292 if (tcp_md5_hash_key(hp, key))
1293 goto clear_hash;
1294 ahash_request_set_crypt(req, NULL, md5_hash, 0);
1295 if (crypto_ahash_final(req))
1296 goto clear_hash;
1297
1298 tcp_put_md5sig_pool();
1299 return 0;
1300
1301clear_hash:
1302 tcp_put_md5sig_pool();
1303clear_hash_noput:
1304 memset(md5_hash, 0, 16);
1305 return 1;
1306}
1307
1308int tcp_v4_md5_hash_skb(char *md5_hash, const struct tcp_md5sig_key *key,
1309 const struct sock *sk,
1310 const struct sk_buff *skb)
1311{
1312 struct tcp_md5sig_pool *hp;
1313 struct ahash_request *req;
1314 const struct tcphdr *th = tcp_hdr(skb);
1315 __be32 saddr, daddr;
1316
1317 if (sk) { /* valid for establish/request sockets */
1318 saddr = sk->sk_rcv_saddr;
1319 daddr = sk->sk_daddr;
1320 } else {
1321 const struct iphdr *iph = ip_hdr(skb);
1322 saddr = iph->saddr;
1323 daddr = iph->daddr;
1324 }
1325
1326 hp = tcp_get_md5sig_pool();
1327 if (!hp)
1328 goto clear_hash_noput;
1329 req = hp->md5_req;
1330
1331 if (crypto_ahash_init(req))
1332 goto clear_hash;
1333
1334 if (tcp_v4_md5_hash_headers(hp, daddr, saddr, th, skb->len))
1335 goto clear_hash;
1336 if (tcp_md5_hash_skb_data(hp, skb, th->doff << 2))
1337 goto clear_hash;
1338 if (tcp_md5_hash_key(hp, key))
1339 goto clear_hash;
1340 ahash_request_set_crypt(req, NULL, md5_hash, 0);
1341 if (crypto_ahash_final(req))
1342 goto clear_hash;
1343
1344 tcp_put_md5sig_pool();
1345 return 0;
1346
1347clear_hash:
1348 tcp_put_md5sig_pool();
1349clear_hash_noput:
1350 memset(md5_hash, 0, 16);
1351 return 1;
1352}
1353EXPORT_SYMBOL(tcp_v4_md5_hash_skb);
1354
1355#endif
1356
1357/* Called with rcu_read_lock() */
1358static bool tcp_v4_inbound_md5_hash(const struct sock *sk,
1359 const struct sk_buff *skb,
1360 int dif, int sdif)
1361{
1362#ifdef CONFIG_TCP_MD5SIG
1363 /*
1364 * This gets called for each TCP segment that arrives
1365 * so we want to be efficient.
1366 * We have 3 drop cases:
1367 * o No MD5 hash and one expected.
1368 * o MD5 hash and we're not expecting one.
1369 * o MD5 hash and its wrong.
1370 */
1371 const __u8 *hash_location = NULL;
1372 struct tcp_md5sig_key *hash_expected;
1373 const struct iphdr *iph = ip_hdr(skb);
1374 const struct tcphdr *th = tcp_hdr(skb);
1375 const union tcp_md5_addr *addr;
1376 unsigned char newhash[16];
1377 int genhash, l3index;
1378
1379 /* sdif set, means packet ingressed via a device
1380 * in an L3 domain and dif is set to the l3mdev
1381 */
1382 l3index = sdif ? dif : 0;
1383
1384 addr = (union tcp_md5_addr *)&iph->saddr;
1385 hash_expected = tcp_md5_do_lookup(sk, l3index, addr, AF_INET);
1386 hash_location = tcp_parse_md5sig_option(th);
1387
1388 /* We've parsed the options - do we have a hash? */
1389 if (!hash_expected && !hash_location)
1390 return false;
1391
1392 if (hash_expected && !hash_location) {
1393 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5NOTFOUND);
1394 return true;
1395 }
1396
1397 if (!hash_expected && hash_location) {
1398 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5UNEXPECTED);
1399 return true;
1400 }
1401
1402 /* Okay, so this is hash_expected and hash_location -
1403 * so we need to calculate the checksum.
1404 */
1405 genhash = tcp_v4_md5_hash_skb(newhash,
1406 hash_expected,
1407 NULL, skb);
1408
1409 if (genhash || memcmp(hash_location, newhash, 16) != 0) {
1410 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5FAILURE);
1411 net_info_ratelimited("MD5 Hash failed for (%pI4, %d)->(%pI4, %d)%s L3 index %d\n",
1412 &iph->saddr, ntohs(th->source),
1413 &iph->daddr, ntohs(th->dest),
1414 genhash ? " tcp_v4_calc_md5_hash failed"
1415 : "", l3index);
1416 return true;
1417 }
1418 return false;
1419#endif
1420 return false;
1421}
1422
1423static void tcp_v4_init_req(struct request_sock *req,
1424 const struct sock *sk_listener,
1425 struct sk_buff *skb)
1426{
1427 struct inet_request_sock *ireq = inet_rsk(req);
1428 struct net *net = sock_net(sk_listener);
1429
1430 sk_rcv_saddr_set(req_to_sk(req), ip_hdr(skb)->daddr);
1431 sk_daddr_set(req_to_sk(req), ip_hdr(skb)->saddr);
1432 RCU_INIT_POINTER(ireq->ireq_opt, tcp_v4_save_options(net, skb));
1433}
1434
1435static struct dst_entry *tcp_v4_route_req(const struct sock *sk,
1436 struct flowi *fl,
1437 const struct request_sock *req)
1438{
1439 return inet_csk_route_req(sk, &fl->u.ip4, req);
1440}
1441
1442struct request_sock_ops tcp_request_sock_ops __read_mostly = {
1443 .family = PF_INET,
1444 .obj_size = sizeof(struct tcp_request_sock),
1445 .rtx_syn_ack = tcp_rtx_synack,
1446 .send_ack = tcp_v4_reqsk_send_ack,
1447 .destructor = tcp_v4_reqsk_destructor,
1448 .send_reset = tcp_v4_send_reset,
1449 .syn_ack_timeout = tcp_syn_ack_timeout,
1450};
1451
1452const struct tcp_request_sock_ops tcp_request_sock_ipv4_ops = {
1453 .mss_clamp = TCP_MSS_DEFAULT,
1454#ifdef CONFIG_TCP_MD5SIG
1455 .req_md5_lookup = tcp_v4_md5_lookup,
1456 .calc_md5_hash = tcp_v4_md5_hash_skb,
1457#endif
1458 .init_req = tcp_v4_init_req,
1459#ifdef CONFIG_SYN_COOKIES
1460 .cookie_init_seq = cookie_v4_init_sequence,
1461#endif
1462 .route_req = tcp_v4_route_req,
1463 .init_seq = tcp_v4_init_seq,
1464 .init_ts_off = tcp_v4_init_ts_off,
1465 .send_synack = tcp_v4_send_synack,
1466};
1467
1468int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
1469{
1470 /* Never answer to SYNs send to broadcast or multicast */
1471 if (skb_rtable(skb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
1472 goto drop;
1473
1474 return tcp_conn_request(&tcp_request_sock_ops,
1475 &tcp_request_sock_ipv4_ops, sk, skb);
1476
1477drop:
1478 tcp_listendrop(sk);
1479 return 0;
1480}
1481EXPORT_SYMBOL(tcp_v4_conn_request);
1482
1483
1484/*
1485 * The three way handshake has completed - we got a valid synack -
1486 * now create the new socket.
1487 */
1488struct sock *tcp_v4_syn_recv_sock(const struct sock *sk, struct sk_buff *skb,
1489 struct request_sock *req,
1490 struct dst_entry *dst,
1491 struct request_sock *req_unhash,
1492 bool *own_req)
1493{
1494 struct inet_request_sock *ireq;
1495 struct inet_sock *newinet;
1496 struct tcp_sock *newtp;
1497 struct sock *newsk;
1498#ifdef CONFIG_TCP_MD5SIG
1499 const union tcp_md5_addr *addr;
1500 struct tcp_md5sig_key *key;
1501 int l3index;
1502#endif
1503 struct ip_options_rcu *inet_opt;
1504
1505 if (sk_acceptq_is_full(sk))
1506 goto exit_overflow;
1507
1508 newsk = tcp_create_openreq_child(sk, req, skb);
1509 if (!newsk)
1510 goto exit_nonewsk;
1511
1512 newsk->sk_gso_type = SKB_GSO_TCPV4;
1513 inet_sk_rx_dst_set(newsk, skb);
1514
1515 newtp = tcp_sk(newsk);
1516 newinet = inet_sk(newsk);
1517 ireq = inet_rsk(req);
1518 sk_daddr_set(newsk, ireq->ir_rmt_addr);
1519 sk_rcv_saddr_set(newsk, ireq->ir_loc_addr);
1520 newsk->sk_bound_dev_if = ireq->ir_iif;
1521 newinet->inet_saddr = ireq->ir_loc_addr;
1522 inet_opt = rcu_dereference(ireq->ireq_opt);
1523 RCU_INIT_POINTER(newinet->inet_opt, inet_opt);
1524 newinet->mc_index = inet_iif(skb);
1525 newinet->mc_ttl = ip_hdr(skb)->ttl;
1526 newinet->rcv_tos = ip_hdr(skb)->tos;
1527 inet_csk(newsk)->icsk_ext_hdr_len = 0;
1528 if (inet_opt)
1529 inet_csk(newsk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
1530 newinet->inet_id = prandom_u32();
1531
1532 if (!dst) {
1533 dst = inet_csk_route_child_sock(sk, newsk, req);
1534 if (!dst)
1535 goto put_and_exit;
1536 } else {
1537 /* syncookie case : see end of cookie_v4_check() */
1538 }
1539 sk_setup_caps(newsk, dst);
1540
1541 tcp_ca_openreq_child(newsk, dst);
1542
1543 tcp_sync_mss(newsk, dst_mtu(dst));
1544 newtp->advmss = tcp_mss_clamp(tcp_sk(sk), dst_metric_advmss(dst));
1545
1546 tcp_initialize_rcv_mss(newsk);
1547
1548#ifdef CONFIG_TCP_MD5SIG
1549 l3index = l3mdev_master_ifindex_by_index(sock_net(sk), ireq->ir_iif);
1550 /* Copy over the MD5 key from the original socket */
1551 addr = (union tcp_md5_addr *)&newinet->inet_daddr;
1552 key = tcp_md5_do_lookup(sk, l3index, addr, AF_INET);
1553 if (key) {
1554 /*
1555 * We're using one, so create a matching key
1556 * on the newsk structure. If we fail to get
1557 * memory, then we end up not copying the key
1558 * across. Shucks.
1559 */
1560 tcp_md5_do_add(newsk, addr, AF_INET, 32, l3index,
1561 key->key, key->keylen, GFP_ATOMIC);
1562 sk_nocaps_add(newsk, NETIF_F_GSO_MASK);
1563 }
1564#endif
1565
1566 if (__inet_inherit_port(sk, newsk) < 0)
1567 goto put_and_exit;
1568 *own_req = inet_ehash_nolisten(newsk, req_to_sk(req_unhash));
1569 if (likely(*own_req)) {
1570 tcp_move_syn(newtp, req);
1571 ireq->ireq_opt = NULL;
1572 } else {
1573 newinet->inet_opt = NULL;
1574 }
1575 return newsk;
1576
1577exit_overflow:
1578 NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
1579exit_nonewsk:
1580 dst_release(dst);
1581exit:
1582 tcp_listendrop(sk);
1583 return NULL;
1584put_and_exit:
1585 newinet->inet_opt = NULL;
1586 inet_csk_prepare_forced_close(newsk);
1587 tcp_done(newsk);
1588 goto exit;
1589}
1590EXPORT_SYMBOL(tcp_v4_syn_recv_sock);
1591
1592static struct sock *tcp_v4_cookie_check(struct sock *sk, struct sk_buff *skb)
1593{
1594#ifdef CONFIG_SYN_COOKIES
1595 const struct tcphdr *th = tcp_hdr(skb);
1596
1597 if (!th->syn)
1598 sk = cookie_v4_check(sk, skb);
1599#endif
1600 return sk;
1601}
1602
1603u16 tcp_v4_get_syncookie(struct sock *sk, struct iphdr *iph,
1604 struct tcphdr *th, u32 *cookie)
1605{
1606 u16 mss = 0;
1607#ifdef CONFIG_SYN_COOKIES
1608 mss = tcp_get_syncookie_mss(&tcp_request_sock_ops,
1609 &tcp_request_sock_ipv4_ops, sk, th);
1610 if (mss) {
1611 *cookie = __cookie_v4_init_sequence(iph, th, &mss);
1612 tcp_synq_overflow(sk);
1613 }
1614#endif
1615 return mss;
1616}
1617
1618/* The socket must have it's spinlock held when we get
1619 * here, unless it is a TCP_LISTEN socket.
1620 *
1621 * We have a potential double-lock case here, so even when
1622 * doing backlog processing we use the BH locking scheme.
1623 * This is because we cannot sleep with the original spinlock
1624 * held.
1625 */
1626int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
1627{
1628 struct sock *rsk;
1629
1630 if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
1631 struct dst_entry *dst = sk->sk_rx_dst;
1632
1633 sock_rps_save_rxhash(sk, skb);
1634 sk_mark_napi_id(sk, skb);
1635 if (dst) {
1636 if (inet_sk(sk)->rx_dst_ifindex != skb->skb_iif ||
1637 !dst->ops->check(dst, 0)) {
1638 dst_release(dst);
1639 sk->sk_rx_dst = NULL;
1640 }
1641 }
1642 tcp_rcv_established(sk, skb);
1643 return 0;
1644 }
1645
1646 if (tcp_checksum_complete(skb))
1647 goto csum_err;
1648
1649 if (sk->sk_state == TCP_LISTEN) {
1650 struct sock *nsk = tcp_v4_cookie_check(sk, skb);
1651
1652 if (!nsk)
1653 goto discard;
1654 if (nsk != sk) {
1655 if (tcp_child_process(sk, nsk, skb)) {
1656 rsk = nsk;
1657 goto reset;
1658 }
1659 return 0;
1660 }
1661 } else
1662 sock_rps_save_rxhash(sk, skb);
1663
1664 if (tcp_rcv_state_process(sk, skb)) {
1665 rsk = sk;
1666 goto reset;
1667 }
1668 return 0;
1669
1670reset:
1671 tcp_v4_send_reset(rsk, skb);
1672discard:
1673 kfree_skb(skb);
1674 /* Be careful here. If this function gets more complicated and
1675 * gcc suffers from register pressure on the x86, sk (in %ebx)
1676 * might be destroyed here. This current version compiles correctly,
1677 * but you have been warned.
1678 */
1679 return 0;
1680
1681csum_err:
1682 TCP_INC_STATS(sock_net(sk), TCP_MIB_CSUMERRORS);
1683 TCP_INC_STATS(sock_net(sk), TCP_MIB_INERRS);
1684 goto discard;
1685}
1686EXPORT_SYMBOL(tcp_v4_do_rcv);
1687
1688int tcp_v4_early_demux(struct sk_buff *skb)
1689{
1690 const struct iphdr *iph;
1691 const struct tcphdr *th;
1692 struct sock *sk;
1693
1694 if (skb->pkt_type != PACKET_HOST)
1695 return 0;
1696
1697 if (!pskb_may_pull(skb, skb_transport_offset(skb) + sizeof(struct tcphdr)))
1698 return 0;
1699
1700 iph = ip_hdr(skb);
1701 th = tcp_hdr(skb);
1702
1703 if (th->doff < sizeof(struct tcphdr) / 4)
1704 return 0;
1705
1706 sk = __inet_lookup_established(dev_net(skb->dev), &tcp_hashinfo,
1707 iph->saddr, th->source,
1708 iph->daddr, ntohs(th->dest),
1709 skb->skb_iif, inet_sdif(skb));
1710 if (sk) {
1711 skb->sk = sk;
1712 skb->destructor = sock_edemux;
1713 if (sk_fullsock(sk)) {
1714 struct dst_entry *dst = READ_ONCE(sk->sk_rx_dst);
1715
1716 if (dst)
1717 dst = dst_check(dst, 0);
1718 if (dst &&
1719 inet_sk(sk)->rx_dst_ifindex == skb->skb_iif)
1720 skb_dst_set_noref(skb, dst);
1721 }
1722 }
1723 return 0;
1724}
1725
1726bool tcp_add_backlog(struct sock *sk, struct sk_buff *skb)
1727{
1728 u32 limit = READ_ONCE(sk->sk_rcvbuf) + READ_ONCE(sk->sk_sndbuf);
1729 struct skb_shared_info *shinfo;
1730 const struct tcphdr *th;
1731 struct tcphdr *thtail;
1732 struct sk_buff *tail;
1733 unsigned int hdrlen;
1734 bool fragstolen;
1735 u32 gso_segs;
1736 int delta;
1737
1738 /* In case all data was pulled from skb frags (in __pskb_pull_tail()),
1739 * we can fix skb->truesize to its real value to avoid future drops.
1740 * This is valid because skb is not yet charged to the socket.
1741 * It has been noticed pure SACK packets were sometimes dropped
1742 * (if cooked by drivers without copybreak feature).
1743 */
1744 skb_condense(skb);
1745
1746 skb_dst_drop(skb);
1747
1748 if (unlikely(tcp_checksum_complete(skb))) {
1749 bh_unlock_sock(sk);
1750 __TCP_INC_STATS(sock_net(sk), TCP_MIB_CSUMERRORS);
1751 __TCP_INC_STATS(sock_net(sk), TCP_MIB_INERRS);
1752 return true;
1753 }
1754
1755 /* Attempt coalescing to last skb in backlog, even if we are
1756 * above the limits.
1757 * This is okay because skb capacity is limited to MAX_SKB_FRAGS.
1758 */
1759 th = (const struct tcphdr *)skb->data;
1760 hdrlen = th->doff * 4;
1761 shinfo = skb_shinfo(skb);
1762
1763 if (!shinfo->gso_size)
1764 shinfo->gso_size = skb->len - hdrlen;
1765
1766 if (!shinfo->gso_segs)
1767 shinfo->gso_segs = 1;
1768
1769 tail = sk->sk_backlog.tail;
1770 if (!tail)
1771 goto no_coalesce;
1772 thtail = (struct tcphdr *)tail->data;
1773
1774 if (TCP_SKB_CB(tail)->end_seq != TCP_SKB_CB(skb)->seq ||
1775 TCP_SKB_CB(tail)->ip_dsfield != TCP_SKB_CB(skb)->ip_dsfield ||
1776 ((TCP_SKB_CB(tail)->tcp_flags |
1777 TCP_SKB_CB(skb)->tcp_flags) & (TCPHDR_SYN | TCPHDR_RST | TCPHDR_URG)) ||
1778 !((TCP_SKB_CB(tail)->tcp_flags &
1779 TCP_SKB_CB(skb)->tcp_flags) & TCPHDR_ACK) ||
1780 ((TCP_SKB_CB(tail)->tcp_flags ^
1781 TCP_SKB_CB(skb)->tcp_flags) & (TCPHDR_ECE | TCPHDR_CWR)) ||
1782#ifdef CONFIG_TLS_DEVICE
1783 tail->decrypted != skb->decrypted ||
1784#endif
1785 thtail->doff != th->doff ||
1786 memcmp(thtail + 1, th + 1, hdrlen - sizeof(*th)))
1787 goto no_coalesce;
1788
1789 __skb_pull(skb, hdrlen);
1790 if (skb_try_coalesce(tail, skb, &fragstolen, &delta)) {
1791 TCP_SKB_CB(tail)->end_seq = TCP_SKB_CB(skb)->end_seq;
1792
1793 if (likely(!before(TCP_SKB_CB(skb)->ack_seq, TCP_SKB_CB(tail)->ack_seq))) {
1794 TCP_SKB_CB(tail)->ack_seq = TCP_SKB_CB(skb)->ack_seq;
1795 thtail->window = th->window;
1796 }
1797
1798 /* We have to update both TCP_SKB_CB(tail)->tcp_flags and
1799 * thtail->fin, so that the fast path in tcp_rcv_established()
1800 * is not entered if we append a packet with a FIN.
1801 * SYN, RST, URG are not present.
1802 * ACK is set on both packets.
1803 * PSH : we do not really care in TCP stack,
1804 * at least for 'GRO' packets.
1805 */
1806 thtail->fin |= th->fin;
1807 TCP_SKB_CB(tail)->tcp_flags |= TCP_SKB_CB(skb)->tcp_flags;
1808
1809 if (TCP_SKB_CB(skb)->has_rxtstamp) {
1810 TCP_SKB_CB(tail)->has_rxtstamp = true;
1811 tail->tstamp = skb->tstamp;
1812 skb_hwtstamps(tail)->hwtstamp = skb_hwtstamps(skb)->hwtstamp;
1813 }
1814
1815 /* Not as strict as GRO. We only need to carry mss max value */
1816 skb_shinfo(tail)->gso_size = max(shinfo->gso_size,
1817 skb_shinfo(tail)->gso_size);
1818
1819 gso_segs = skb_shinfo(tail)->gso_segs + shinfo->gso_segs;
1820 skb_shinfo(tail)->gso_segs = min_t(u32, gso_segs, 0xFFFF);
1821
1822 sk->sk_backlog.len += delta;
1823 __NET_INC_STATS(sock_net(sk),
1824 LINUX_MIB_TCPBACKLOGCOALESCE);
1825 kfree_skb_partial(skb, fragstolen);
1826 return false;
1827 }
1828 __skb_push(skb, hdrlen);
1829
1830no_coalesce:
1831 /* Only socket owner can try to collapse/prune rx queues
1832 * to reduce memory overhead, so add a little headroom here.
1833 * Few sockets backlog are possibly concurrently non empty.
1834 */
1835 limit += 64*1024;
1836
1837 if (unlikely(sk_add_backlog(sk, skb, limit))) {
1838 bh_unlock_sock(sk);
1839 __NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPBACKLOGDROP);
1840 return true;
1841 }
1842 return false;
1843}
1844EXPORT_SYMBOL(tcp_add_backlog);
1845
1846int tcp_filter(struct sock *sk, struct sk_buff *skb)
1847{
1848 struct tcphdr *th = (struct tcphdr *)skb->data;
1849
1850 return sk_filter_trim_cap(sk, skb, th->doff * 4);
1851}
1852EXPORT_SYMBOL(tcp_filter);
1853
1854static void tcp_v4_restore_cb(struct sk_buff *skb)
1855{
1856 memmove(IPCB(skb), &TCP_SKB_CB(skb)->header.h4,
1857 sizeof(struct inet_skb_parm));
1858}
1859
1860static void tcp_v4_fill_cb(struct sk_buff *skb, const struct iphdr *iph,
1861 const struct tcphdr *th)
1862{
1863 /* This is tricky : We move IPCB at its correct location into TCP_SKB_CB()
1864 * barrier() makes sure compiler wont play fool^Waliasing games.
1865 */
1866 memmove(&TCP_SKB_CB(skb)->header.h4, IPCB(skb),
1867 sizeof(struct inet_skb_parm));
1868 barrier();
1869
1870 TCP_SKB_CB(skb)->seq = ntohl(th->seq);
1871 TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
1872 skb->len - th->doff * 4);
1873 TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
1874 TCP_SKB_CB(skb)->tcp_flags = tcp_flag_byte(th);
1875 TCP_SKB_CB(skb)->tcp_tw_isn = 0;
1876 TCP_SKB_CB(skb)->ip_dsfield = ipv4_get_dsfield(iph);
1877 TCP_SKB_CB(skb)->sacked = 0;
1878 TCP_SKB_CB(skb)->has_rxtstamp =
1879 skb->tstamp || skb_hwtstamps(skb)->hwtstamp;
1880}
1881
1882/*
1883 * From tcp_input.c
1884 */
1885
1886int tcp_v4_rcv(struct sk_buff *skb)
1887{
1888 struct net *net = dev_net(skb->dev);
1889 struct sk_buff *skb_to_free;
1890 int sdif = inet_sdif(skb);
1891 int dif = inet_iif(skb);
1892 const struct iphdr *iph;
1893 const struct tcphdr *th;
1894 bool refcounted;
1895 struct sock *sk;
1896 int ret;
1897
1898 if (skb->pkt_type != PACKET_HOST)
1899 goto discard_it;
1900
1901 /* Count it even if it's bad */
1902 __TCP_INC_STATS(net, TCP_MIB_INSEGS);
1903
1904 if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
1905 goto discard_it;
1906
1907 th = (const struct tcphdr *)skb->data;
1908
1909 if (unlikely(th->doff < sizeof(struct tcphdr) / 4))
1910 goto bad_packet;
1911 if (!pskb_may_pull(skb, th->doff * 4))
1912 goto discard_it;
1913
1914 /* An explanation is required here, I think.
1915 * Packet length and doff are validated by header prediction,
1916 * provided case of th->doff==0 is eliminated.
1917 * So, we defer the checks. */
1918
1919 if (skb_checksum_init(skb, IPPROTO_TCP, inet_compute_pseudo))
1920 goto csum_error;
1921
1922 th = (const struct tcphdr *)skb->data;
1923 iph = ip_hdr(skb);
1924lookup:
1925 sk = __inet_lookup_skb(&tcp_hashinfo, skb, __tcp_hdrlen(th), th->source,
1926 th->dest, sdif, &refcounted);
1927 if (!sk)
1928 goto no_tcp_socket;
1929
1930process:
1931 if (sk->sk_state == TCP_TIME_WAIT)
1932 goto do_time_wait;
1933
1934 if (sk->sk_state == TCP_NEW_SYN_RECV) {
1935 struct request_sock *req = inet_reqsk(sk);
1936 bool req_stolen = false;
1937 struct sock *nsk;
1938
1939 sk = req->rsk_listener;
1940 if (unlikely(tcp_v4_inbound_md5_hash(sk, skb, dif, sdif))) {
1941 sk_drops_add(sk, skb);
1942 reqsk_put(req);
1943 goto discard_it;
1944 }
1945 if (tcp_checksum_complete(skb)) {
1946 reqsk_put(req);
1947 goto csum_error;
1948 }
1949 if (unlikely(sk->sk_state != TCP_LISTEN)) {
1950 inet_csk_reqsk_queue_drop_and_put(sk, req);
1951 goto lookup;
1952 }
1953 /* We own a reference on the listener, increase it again
1954 * as we might lose it too soon.
1955 */
1956 sock_hold(sk);
1957 refcounted = true;
1958 nsk = NULL;
1959 if (!tcp_filter(sk, skb)) {
1960 th = (const struct tcphdr *)skb->data;
1961 iph = ip_hdr(skb);
1962 tcp_v4_fill_cb(skb, iph, th);
1963 nsk = tcp_check_req(sk, skb, req, false, &req_stolen);
1964 }
1965 if (!nsk) {
1966 reqsk_put(req);
1967 if (req_stolen) {
1968 /* Another cpu got exclusive access to req
1969 * and created a full blown socket.
1970 * Try to feed this packet to this socket
1971 * instead of discarding it.
1972 */
1973 tcp_v4_restore_cb(skb);
1974 sock_put(sk);
1975 goto lookup;
1976 }
1977 goto discard_and_relse;
1978 }
1979 if (nsk == sk) {
1980 reqsk_put(req);
1981 tcp_v4_restore_cb(skb);
1982 } else if (tcp_child_process(sk, nsk, skb)) {
1983 tcp_v4_send_reset(nsk, skb);
1984 goto discard_and_relse;
1985 } else {
1986 sock_put(sk);
1987 return 0;
1988 }
1989 }
1990 if (unlikely(iph->ttl < inet_sk(sk)->min_ttl)) {
1991 __NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP);
1992 goto discard_and_relse;
1993 }
1994
1995 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
1996 goto discard_and_relse;
1997
1998 if (tcp_v4_inbound_md5_hash(sk, skb, dif, sdif))
1999 goto discard_and_relse;
2000
2001 nf_reset_ct(skb);
2002
2003 if (tcp_filter(sk, skb))
2004 goto discard_and_relse;
2005 th = (const struct tcphdr *)skb->data;
2006 iph = ip_hdr(skb);
2007 tcp_v4_fill_cb(skb, iph, th);
2008
2009 skb->dev = NULL;
2010
2011 if (sk->sk_state == TCP_LISTEN) {
2012 ret = tcp_v4_do_rcv(sk, skb);
2013 goto put_and_return;
2014 }
2015
2016 sk_incoming_cpu_update(sk);
2017
2018 bh_lock_sock_nested(sk);
2019 tcp_segs_in(tcp_sk(sk), skb);
2020 ret = 0;
2021 if (!sock_owned_by_user(sk)) {
2022 skb_to_free = sk->sk_rx_skb_cache;
2023 sk->sk_rx_skb_cache = NULL;
2024 ret = tcp_v4_do_rcv(sk, skb);
2025 } else {
2026 if (tcp_add_backlog(sk, skb))
2027 goto discard_and_relse;
2028 skb_to_free = NULL;
2029 }
2030 bh_unlock_sock(sk);
2031 if (skb_to_free)
2032 __kfree_skb(skb_to_free);
2033
2034put_and_return:
2035 if (refcounted)
2036 sock_put(sk);
2037
2038 return ret;
2039
2040no_tcp_socket:
2041 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
2042 goto discard_it;
2043
2044 tcp_v4_fill_cb(skb, iph, th);
2045
2046 if (tcp_checksum_complete(skb)) {
2047csum_error:
2048 __TCP_INC_STATS(net, TCP_MIB_CSUMERRORS);
2049bad_packet:
2050 __TCP_INC_STATS(net, TCP_MIB_INERRS);
2051 } else {
2052 tcp_v4_send_reset(NULL, skb);
2053 }
2054
2055discard_it:
2056 /* Discard frame. */
2057 kfree_skb(skb);
2058 return 0;
2059
2060discard_and_relse:
2061 sk_drops_add(sk, skb);
2062 if (refcounted)
2063 sock_put(sk);
2064 goto discard_it;
2065
2066do_time_wait:
2067 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
2068 inet_twsk_put(inet_twsk(sk));
2069 goto discard_it;
2070 }
2071
2072 tcp_v4_fill_cb(skb, iph, th);
2073
2074 if (tcp_checksum_complete(skb)) {
2075 inet_twsk_put(inet_twsk(sk));
2076 goto csum_error;
2077 }
2078 switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) {
2079 case TCP_TW_SYN: {
2080 struct sock *sk2 = inet_lookup_listener(dev_net(skb->dev),
2081 &tcp_hashinfo, skb,
2082 __tcp_hdrlen(th),
2083 iph->saddr, th->source,
2084 iph->daddr, th->dest,
2085 inet_iif(skb),
2086 sdif);
2087 if (sk2) {
2088 inet_twsk_deschedule_put(inet_twsk(sk));
2089 sk = sk2;
2090 tcp_v4_restore_cb(skb);
2091 refcounted = false;
2092 goto process;
2093 }
2094 }
2095 /* to ACK */
2096 fallthrough;
2097 case TCP_TW_ACK:
2098 tcp_v4_timewait_ack(sk, skb);
2099 break;
2100 case TCP_TW_RST:
2101 tcp_v4_send_reset(sk, skb);
2102 inet_twsk_deschedule_put(inet_twsk(sk));
2103 goto discard_it;
2104 case TCP_TW_SUCCESS:;
2105 }
2106 goto discard_it;
2107}
2108
2109static struct timewait_sock_ops tcp_timewait_sock_ops = {
2110 .twsk_obj_size = sizeof(struct tcp_timewait_sock),
2111 .twsk_unique = tcp_twsk_unique,
2112 .twsk_destructor= tcp_twsk_destructor,
2113};
2114
2115void inet_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb)
2116{
2117 struct dst_entry *dst = skb_dst(skb);
2118
2119 if (dst && dst_hold_safe(dst)) {
2120 sk->sk_rx_dst = dst;
2121 inet_sk(sk)->rx_dst_ifindex = skb->skb_iif;
2122 }
2123}
2124EXPORT_SYMBOL(inet_sk_rx_dst_set);
2125
2126const struct inet_connection_sock_af_ops ipv4_specific = {
2127 .queue_xmit = ip_queue_xmit,
2128 .send_check = tcp_v4_send_check,
2129 .rebuild_header = inet_sk_rebuild_header,
2130 .sk_rx_dst_set = inet_sk_rx_dst_set,
2131 .conn_request = tcp_v4_conn_request,
2132 .syn_recv_sock = tcp_v4_syn_recv_sock,
2133 .net_header_len = sizeof(struct iphdr),
2134 .setsockopt = ip_setsockopt,
2135 .getsockopt = ip_getsockopt,
2136 .addr2sockaddr = inet_csk_addr2sockaddr,
2137 .sockaddr_len = sizeof(struct sockaddr_in),
2138 .mtu_reduced = tcp_v4_mtu_reduced,
2139};
2140EXPORT_SYMBOL(ipv4_specific);
2141
2142#ifdef CONFIG_TCP_MD5SIG
2143static const struct tcp_sock_af_ops tcp_sock_ipv4_specific = {
2144 .md5_lookup = tcp_v4_md5_lookup,
2145 .calc_md5_hash = tcp_v4_md5_hash_skb,
2146 .md5_parse = tcp_v4_parse_md5_keys,
2147};
2148#endif
2149
2150/* NOTE: A lot of things set to zero explicitly by call to
2151 * sk_alloc() so need not be done here.
2152 */
2153static int tcp_v4_init_sock(struct sock *sk)
2154{
2155 struct inet_connection_sock *icsk = inet_csk(sk);
2156
2157 tcp_init_sock(sk);
2158
2159 icsk->icsk_af_ops = &ipv4_specific;
2160
2161#ifdef CONFIG_TCP_MD5SIG
2162 tcp_sk(sk)->af_specific = &tcp_sock_ipv4_specific;
2163#endif
2164
2165 return 0;
2166}
2167
2168void tcp_v4_destroy_sock(struct sock *sk)
2169{
2170 struct tcp_sock *tp = tcp_sk(sk);
2171
2172 trace_tcp_destroy_sock(sk);
2173
2174 tcp_clear_xmit_timers(sk);
2175
2176 tcp_cleanup_congestion_control(sk);
2177
2178 tcp_cleanup_ulp(sk);
2179
2180 /* Cleanup up the write buffer. */
2181 tcp_write_queue_purge(sk);
2182
2183 /* Check if we want to disable active TFO */
2184 tcp_fastopen_active_disable_ofo_check(sk);
2185
2186 /* Cleans up our, hopefully empty, out_of_order_queue. */
2187 skb_rbtree_purge(&tp->out_of_order_queue);
2188
2189#ifdef CONFIG_TCP_MD5SIG
2190 /* Clean up the MD5 key list, if any */
2191 if (tp->md5sig_info) {
2192 tcp_clear_md5_list(sk);
2193 kfree_rcu(rcu_dereference_protected(tp->md5sig_info, 1), rcu);
2194 tp->md5sig_info = NULL;
2195 }
2196#endif
2197
2198 /* Clean up a referenced TCP bind bucket. */
2199 if (inet_csk(sk)->icsk_bind_hash)
2200 inet_put_port(sk);
2201
2202 BUG_ON(rcu_access_pointer(tp->fastopen_rsk));
2203
2204 /* If socket is aborted during connect operation */
2205 tcp_free_fastopen_req(tp);
2206 tcp_fastopen_destroy_cipher(sk);
2207 tcp_saved_syn_free(tp);
2208
2209 sk_sockets_allocated_dec(sk);
2210}
2211EXPORT_SYMBOL(tcp_v4_destroy_sock);
2212
2213#ifdef CONFIG_PROC_FS
2214/* Proc filesystem TCP sock list dumping. */
2215
2216/*
2217 * Get next listener socket follow cur. If cur is NULL, get first socket
2218 * starting from bucket given in st->bucket; when st->bucket is zero the
2219 * very first socket in the hash table is returned.
2220 */
2221static void *listening_get_next(struct seq_file *seq, void *cur)
2222{
2223 struct tcp_seq_afinfo *afinfo;
2224 struct tcp_iter_state *st = seq->private;
2225 struct net *net = seq_file_net(seq);
2226 struct inet_listen_hashbucket *ilb;
2227 struct hlist_nulls_node *node;
2228 struct sock *sk = cur;
2229
2230 if (st->bpf_seq_afinfo)
2231 afinfo = st->bpf_seq_afinfo;
2232 else
2233 afinfo = PDE_DATA(file_inode(seq->file));
2234
2235 if (!sk) {
2236get_head:
2237 ilb = &tcp_hashinfo.listening_hash[st->bucket];
2238 spin_lock(&ilb->lock);
2239 sk = sk_nulls_head(&ilb->nulls_head);
2240 st->offset = 0;
2241 goto get_sk;
2242 }
2243 ilb = &tcp_hashinfo.listening_hash[st->bucket];
2244 ++st->num;
2245 ++st->offset;
2246
2247 sk = sk_nulls_next(sk);
2248get_sk:
2249 sk_nulls_for_each_from(sk, node) {
2250 if (!net_eq(sock_net(sk), net))
2251 continue;
2252 if (afinfo->family == AF_UNSPEC ||
2253 sk->sk_family == afinfo->family)
2254 return sk;
2255 }
2256 spin_unlock(&ilb->lock);
2257 st->offset = 0;
2258 if (++st->bucket < INET_LHTABLE_SIZE)
2259 goto get_head;
2260 return NULL;
2261}
2262
2263static void *listening_get_idx(struct seq_file *seq, loff_t *pos)
2264{
2265 struct tcp_iter_state *st = seq->private;
2266 void *rc;
2267
2268 st->bucket = 0;
2269 st->offset = 0;
2270 rc = listening_get_next(seq, NULL);
2271
2272 while (rc && *pos) {
2273 rc = listening_get_next(seq, rc);
2274 --*pos;
2275 }
2276 return rc;
2277}
2278
2279static inline bool empty_bucket(const struct tcp_iter_state *st)
2280{
2281 return hlist_nulls_empty(&tcp_hashinfo.ehash[st->bucket].chain);
2282}
2283
2284/*
2285 * Get first established socket starting from bucket given in st->bucket.
2286 * If st->bucket is zero, the very first socket in the hash is returned.
2287 */
2288static void *established_get_first(struct seq_file *seq)
2289{
2290 struct tcp_seq_afinfo *afinfo;
2291 struct tcp_iter_state *st = seq->private;
2292 struct net *net = seq_file_net(seq);
2293 void *rc = NULL;
2294
2295 if (st->bpf_seq_afinfo)
2296 afinfo = st->bpf_seq_afinfo;
2297 else
2298 afinfo = PDE_DATA(file_inode(seq->file));
2299
2300 st->offset = 0;
2301 for (; st->bucket <= tcp_hashinfo.ehash_mask; ++st->bucket) {
2302 struct sock *sk;
2303 struct hlist_nulls_node *node;
2304 spinlock_t *lock = inet_ehash_lockp(&tcp_hashinfo, st->bucket);
2305
2306 /* Lockless fast path for the common case of empty buckets */
2307 if (empty_bucket(st))
2308 continue;
2309
2310 spin_lock_bh(lock);
2311 sk_nulls_for_each(sk, node, &tcp_hashinfo.ehash[st->bucket].chain) {
2312 if ((afinfo->family != AF_UNSPEC &&
2313 sk->sk_family != afinfo->family) ||
2314 !net_eq(sock_net(sk), net)) {
2315 continue;
2316 }
2317 rc = sk;
2318 goto out;
2319 }
2320 spin_unlock_bh(lock);
2321 }
2322out:
2323 return rc;
2324}
2325
2326static void *established_get_next(struct seq_file *seq, void *cur)
2327{
2328 struct tcp_seq_afinfo *afinfo;
2329 struct sock *sk = cur;
2330 struct hlist_nulls_node *node;
2331 struct tcp_iter_state *st = seq->private;
2332 struct net *net = seq_file_net(seq);
2333
2334 if (st->bpf_seq_afinfo)
2335 afinfo = st->bpf_seq_afinfo;
2336 else
2337 afinfo = PDE_DATA(file_inode(seq->file));
2338
2339 ++st->num;
2340 ++st->offset;
2341
2342 sk = sk_nulls_next(sk);
2343
2344 sk_nulls_for_each_from(sk, node) {
2345 if ((afinfo->family == AF_UNSPEC ||
2346 sk->sk_family == afinfo->family) &&
2347 net_eq(sock_net(sk), net))
2348 return sk;
2349 }
2350
2351 spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
2352 ++st->bucket;
2353 return established_get_first(seq);
2354}
2355
2356static void *established_get_idx(struct seq_file *seq, loff_t pos)
2357{
2358 struct tcp_iter_state *st = seq->private;
2359 void *rc;
2360
2361 st->bucket = 0;
2362 rc = established_get_first(seq);
2363
2364 while (rc && pos) {
2365 rc = established_get_next(seq, rc);
2366 --pos;
2367 }
2368 return rc;
2369}
2370
2371static void *tcp_get_idx(struct seq_file *seq, loff_t pos)
2372{
2373 void *rc;
2374 struct tcp_iter_state *st = seq->private;
2375
2376 st->state = TCP_SEQ_STATE_LISTENING;
2377 rc = listening_get_idx(seq, &pos);
2378
2379 if (!rc) {
2380 st->state = TCP_SEQ_STATE_ESTABLISHED;
2381 rc = established_get_idx(seq, pos);
2382 }
2383
2384 return rc;
2385}
2386
2387static void *tcp_seek_last_pos(struct seq_file *seq)
2388{
2389 struct tcp_iter_state *st = seq->private;
2390 int offset = st->offset;
2391 int orig_num = st->num;
2392 void *rc = NULL;
2393
2394 switch (st->state) {
2395 case TCP_SEQ_STATE_LISTENING:
2396 if (st->bucket >= INET_LHTABLE_SIZE)
2397 break;
2398 st->state = TCP_SEQ_STATE_LISTENING;
2399 rc = listening_get_next(seq, NULL);
2400 while (offset-- && rc)
2401 rc = listening_get_next(seq, rc);
2402 if (rc)
2403 break;
2404 st->bucket = 0;
2405 st->state = TCP_SEQ_STATE_ESTABLISHED;
2406 fallthrough;
2407 case TCP_SEQ_STATE_ESTABLISHED:
2408 if (st->bucket > tcp_hashinfo.ehash_mask)
2409 break;
2410 rc = established_get_first(seq);
2411 while (offset-- && rc)
2412 rc = established_get_next(seq, rc);
2413 }
2414
2415 st->num = orig_num;
2416
2417 return rc;
2418}
2419
2420void *tcp_seq_start(struct seq_file *seq, loff_t *pos)
2421{
2422 struct tcp_iter_state *st = seq->private;
2423 void *rc;
2424
2425 if (*pos && *pos == st->last_pos) {
2426 rc = tcp_seek_last_pos(seq);
2427 if (rc)
2428 goto out;
2429 }
2430
2431 st->state = TCP_SEQ_STATE_LISTENING;
2432 st->num = 0;
2433 st->bucket = 0;
2434 st->offset = 0;
2435 rc = *pos ? tcp_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
2436
2437out:
2438 st->last_pos = *pos;
2439 return rc;
2440}
2441EXPORT_SYMBOL(tcp_seq_start);
2442
2443void *tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2444{
2445 struct tcp_iter_state *st = seq->private;
2446 void *rc = NULL;
2447
2448 if (v == SEQ_START_TOKEN) {
2449 rc = tcp_get_idx(seq, 0);
2450 goto out;
2451 }
2452
2453 switch (st->state) {
2454 case TCP_SEQ_STATE_LISTENING:
2455 rc = listening_get_next(seq, v);
2456 if (!rc) {
2457 st->state = TCP_SEQ_STATE_ESTABLISHED;
2458 st->bucket = 0;
2459 st->offset = 0;
2460 rc = established_get_first(seq);
2461 }
2462 break;
2463 case TCP_SEQ_STATE_ESTABLISHED:
2464 rc = established_get_next(seq, v);
2465 break;
2466 }
2467out:
2468 ++*pos;
2469 st->last_pos = *pos;
2470 return rc;
2471}
2472EXPORT_SYMBOL(tcp_seq_next);
2473
2474void tcp_seq_stop(struct seq_file *seq, void *v)
2475{
2476 struct tcp_iter_state *st = seq->private;
2477
2478 switch (st->state) {
2479 case TCP_SEQ_STATE_LISTENING:
2480 if (v != SEQ_START_TOKEN)
2481 spin_unlock(&tcp_hashinfo.listening_hash[st->bucket].lock);
2482 break;
2483 case TCP_SEQ_STATE_ESTABLISHED:
2484 if (v)
2485 spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
2486 break;
2487 }
2488}
2489EXPORT_SYMBOL(tcp_seq_stop);
2490
2491static void get_openreq4(const struct request_sock *req,
2492 struct seq_file *f, int i)
2493{
2494 const struct inet_request_sock *ireq = inet_rsk(req);
2495 long delta = req->rsk_timer.expires - jiffies;
2496
2497 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2498 " %02X %08X:%08X %02X:%08lX %08X %5u %8d %u %d %pK",
2499 i,
2500 ireq->ir_loc_addr,
2501 ireq->ir_num,
2502 ireq->ir_rmt_addr,
2503 ntohs(ireq->ir_rmt_port),
2504 TCP_SYN_RECV,
2505 0, 0, /* could print option size, but that is af dependent. */
2506 1, /* timers active (only the expire timer) */
2507 jiffies_delta_to_clock_t(delta),
2508 req->num_timeout,
2509 from_kuid_munged(seq_user_ns(f),
2510 sock_i_uid(req->rsk_listener)),
2511 0, /* non standard timer */
2512 0, /* open_requests have no inode */
2513 0,
2514 req);
2515}
2516
2517static void get_tcp4_sock(struct sock *sk, struct seq_file *f, int i)
2518{
2519 int timer_active;
2520 unsigned long timer_expires;
2521 const struct tcp_sock *tp = tcp_sk(sk);
2522 const struct inet_connection_sock *icsk = inet_csk(sk);
2523 const struct inet_sock *inet = inet_sk(sk);
2524 const struct fastopen_queue *fastopenq = &icsk->icsk_accept_queue.fastopenq;
2525 __be32 dest = inet->inet_daddr;
2526 __be32 src = inet->inet_rcv_saddr;
2527 __u16 destp = ntohs(inet->inet_dport);
2528 __u16 srcp = ntohs(inet->inet_sport);
2529 int rx_queue;
2530 int state;
2531
2532 if (icsk->icsk_pending == ICSK_TIME_RETRANS ||
2533 icsk->icsk_pending == ICSK_TIME_REO_TIMEOUT ||
2534 icsk->icsk_pending == ICSK_TIME_LOSS_PROBE) {
2535 timer_active = 1;
2536 timer_expires = icsk->icsk_timeout;
2537 } else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
2538 timer_active = 4;
2539 timer_expires = icsk->icsk_timeout;
2540 } else if (timer_pending(&sk->sk_timer)) {
2541 timer_active = 2;
2542 timer_expires = sk->sk_timer.expires;
2543 } else {
2544 timer_active = 0;
2545 timer_expires = jiffies;
2546 }
2547
2548 state = inet_sk_state_load(sk);
2549 if (state == TCP_LISTEN)
2550 rx_queue = READ_ONCE(sk->sk_ack_backlog);
2551 else
2552 /* Because we don't lock the socket,
2553 * we might find a transient negative value.
2554 */
2555 rx_queue = max_t(int, READ_ONCE(tp->rcv_nxt) -
2556 READ_ONCE(tp->copied_seq), 0);
2557
2558 seq_printf(f, "%4d: %08X:%04X %08X:%04X %02X %08X:%08X %02X:%08lX "
2559 "%08X %5u %8d %lu %d %pK %lu %lu %u %u %d",
2560 i, src, srcp, dest, destp, state,
2561 READ_ONCE(tp->write_seq) - tp->snd_una,
2562 rx_queue,
2563 timer_active,
2564 jiffies_delta_to_clock_t(timer_expires - jiffies),
2565 icsk->icsk_retransmits,
2566 from_kuid_munged(seq_user_ns(f), sock_i_uid(sk)),
2567 icsk->icsk_probes_out,
2568 sock_i_ino(sk),
2569 refcount_read(&sk->sk_refcnt), sk,
2570 jiffies_to_clock_t(icsk->icsk_rto),
2571 jiffies_to_clock_t(icsk->icsk_ack.ato),
2572 (icsk->icsk_ack.quick << 1) | inet_csk_in_pingpong_mode(sk),
2573 tp->snd_cwnd,
2574 state == TCP_LISTEN ?
2575 fastopenq->max_qlen :
2576 (tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh));
2577}
2578
2579static void get_timewait4_sock(const struct inet_timewait_sock *tw,
2580 struct seq_file *f, int i)
2581{
2582 long delta = tw->tw_timer.expires - jiffies;
2583 __be32 dest, src;
2584 __u16 destp, srcp;
2585
2586 dest = tw->tw_daddr;
2587 src = tw->tw_rcv_saddr;
2588 destp = ntohs(tw->tw_dport);
2589 srcp = ntohs(tw->tw_sport);
2590
2591 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2592 " %02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK",
2593 i, src, srcp, dest, destp, tw->tw_substate, 0, 0,
2594 3, jiffies_delta_to_clock_t(delta), 0, 0, 0, 0,
2595 refcount_read(&tw->tw_refcnt), tw);
2596}
2597
2598#define TMPSZ 150
2599
2600static int tcp4_seq_show(struct seq_file *seq, void *v)
2601{
2602 struct tcp_iter_state *st;
2603 struct sock *sk = v;
2604
2605 seq_setwidth(seq, TMPSZ - 1);
2606 if (v == SEQ_START_TOKEN) {
2607 seq_puts(seq, " sl local_address rem_address st tx_queue "
2608 "rx_queue tr tm->when retrnsmt uid timeout "
2609 "inode");
2610 goto out;
2611 }
2612 st = seq->private;
2613
2614 if (sk->sk_state == TCP_TIME_WAIT)
2615 get_timewait4_sock(v, seq, st->num);
2616 else if (sk->sk_state == TCP_NEW_SYN_RECV)
2617 get_openreq4(v, seq, st->num);
2618 else
2619 get_tcp4_sock(v, seq, st->num);
2620out:
2621 seq_pad(seq, '\n');
2622 return 0;
2623}
2624
2625#ifdef CONFIG_BPF_SYSCALL
2626struct bpf_iter__tcp {
2627 __bpf_md_ptr(struct bpf_iter_meta *, meta);
2628 __bpf_md_ptr(struct sock_common *, sk_common);
2629 uid_t uid __aligned(8);
2630};
2631
2632static int tcp_prog_seq_show(struct bpf_prog *prog, struct bpf_iter_meta *meta,
2633 struct sock_common *sk_common, uid_t uid)
2634{
2635 struct bpf_iter__tcp ctx;
2636
2637 meta->seq_num--; /* skip SEQ_START_TOKEN */
2638 ctx.meta = meta;
2639 ctx.sk_common = sk_common;
2640 ctx.uid = uid;
2641 return bpf_iter_run_prog(prog, &ctx);
2642}
2643
2644static int bpf_iter_tcp_seq_show(struct seq_file *seq, void *v)
2645{
2646 struct bpf_iter_meta meta;
2647 struct bpf_prog *prog;
2648 struct sock *sk = v;
2649 uid_t uid;
2650
2651 if (v == SEQ_START_TOKEN)
2652 return 0;
2653
2654 if (sk->sk_state == TCP_TIME_WAIT) {
2655 uid = 0;
2656 } else if (sk->sk_state == TCP_NEW_SYN_RECV) {
2657 const struct request_sock *req = v;
2658
2659 uid = from_kuid_munged(seq_user_ns(seq),
2660 sock_i_uid(req->rsk_listener));
2661 } else {
2662 uid = from_kuid_munged(seq_user_ns(seq), sock_i_uid(sk));
2663 }
2664
2665 meta.seq = seq;
2666 prog = bpf_iter_get_info(&meta, false);
2667 return tcp_prog_seq_show(prog, &meta, v, uid);
2668}
2669
2670static void bpf_iter_tcp_seq_stop(struct seq_file *seq, void *v)
2671{
2672 struct bpf_iter_meta meta;
2673 struct bpf_prog *prog;
2674
2675 if (!v) {
2676 meta.seq = seq;
2677 prog = bpf_iter_get_info(&meta, true);
2678 if (prog)
2679 (void)tcp_prog_seq_show(prog, &meta, v, 0);
2680 }
2681
2682 tcp_seq_stop(seq, v);
2683}
2684
2685static const struct seq_operations bpf_iter_tcp_seq_ops = {
2686 .show = bpf_iter_tcp_seq_show,
2687 .start = tcp_seq_start,
2688 .next = tcp_seq_next,
2689 .stop = bpf_iter_tcp_seq_stop,
2690};
2691#endif
2692
2693static const struct seq_operations tcp4_seq_ops = {
2694 .show = tcp4_seq_show,
2695 .start = tcp_seq_start,
2696 .next = tcp_seq_next,
2697 .stop = tcp_seq_stop,
2698};
2699
2700static struct tcp_seq_afinfo tcp4_seq_afinfo = {
2701 .family = AF_INET,
2702};
2703
2704static int __net_init tcp4_proc_init_net(struct net *net)
2705{
2706 if (!proc_create_net_data("tcp", 0444, net->proc_net, &tcp4_seq_ops,
2707 sizeof(struct tcp_iter_state), &tcp4_seq_afinfo))
2708 return -ENOMEM;
2709 return 0;
2710}
2711
2712static void __net_exit tcp4_proc_exit_net(struct net *net)
2713{
2714 remove_proc_entry("tcp", net->proc_net);
2715}
2716
2717static struct pernet_operations tcp4_net_ops = {
2718 .init = tcp4_proc_init_net,
2719 .exit = tcp4_proc_exit_net,
2720};
2721
2722int __init tcp4_proc_init(void)
2723{
2724 return register_pernet_subsys(&tcp4_net_ops);
2725}
2726
2727void tcp4_proc_exit(void)
2728{
2729 unregister_pernet_subsys(&tcp4_net_ops);
2730}
2731#endif /* CONFIG_PROC_FS */
2732
2733struct proto tcp_prot = {
2734 .name = "TCP",
2735 .owner = THIS_MODULE,
2736 .close = tcp_close,
2737 .pre_connect = tcp_v4_pre_connect,
2738 .connect = tcp_v4_connect,
2739 .disconnect = tcp_disconnect,
2740 .accept = inet_csk_accept,
2741 .ioctl = tcp_ioctl,
2742 .init = tcp_v4_init_sock,
2743 .destroy = tcp_v4_destroy_sock,
2744 .shutdown = tcp_shutdown,
2745 .setsockopt = tcp_setsockopt,
2746 .getsockopt = tcp_getsockopt,
2747 .keepalive = tcp_set_keepalive,
2748 .recvmsg = tcp_recvmsg,
2749 .sendmsg = tcp_sendmsg,
2750 .sendpage = tcp_sendpage,
2751 .backlog_rcv = tcp_v4_do_rcv,
2752 .release_cb = tcp_release_cb,
2753 .hash = inet_hash,
2754 .unhash = inet_unhash,
2755 .get_port = inet_csk_get_port,
2756 .enter_memory_pressure = tcp_enter_memory_pressure,
2757 .leave_memory_pressure = tcp_leave_memory_pressure,
2758 .stream_memory_free = tcp_stream_memory_free,
2759 .sockets_allocated = &tcp_sockets_allocated,
2760 .orphan_count = &tcp_orphan_count,
2761 .memory_allocated = &tcp_memory_allocated,
2762 .memory_pressure = &tcp_memory_pressure,
2763 .sysctl_mem = sysctl_tcp_mem,
2764 .sysctl_wmem_offset = offsetof(struct net, ipv4.sysctl_tcp_wmem),
2765 .sysctl_rmem_offset = offsetof(struct net, ipv4.sysctl_tcp_rmem),
2766 .max_header = MAX_TCP_HEADER,
2767 .obj_size = sizeof(struct tcp_sock),
2768 .slab_flags = SLAB_TYPESAFE_BY_RCU,
2769 .twsk_prot = &tcp_timewait_sock_ops,
2770 .rsk_prot = &tcp_request_sock_ops,
2771 .h.hashinfo = &tcp_hashinfo,
2772 .no_autobind = true,
2773 .diag_destroy = tcp_abort,
2774};
2775EXPORT_SYMBOL(tcp_prot);
2776
2777static void __net_exit tcp_sk_exit(struct net *net)
2778{
2779 int cpu;
2780
2781 if (net->ipv4.tcp_congestion_control)
2782 bpf_module_put(net->ipv4.tcp_congestion_control,
2783 net->ipv4.tcp_congestion_control->owner);
2784
2785 for_each_possible_cpu(cpu)
2786 inet_ctl_sock_destroy(*per_cpu_ptr(net->ipv4.tcp_sk, cpu));
2787 free_percpu(net->ipv4.tcp_sk);
2788}
2789
2790static int __net_init tcp_sk_init(struct net *net)
2791{
2792 int res, cpu, cnt;
2793
2794 net->ipv4.tcp_sk = alloc_percpu(struct sock *);
2795 if (!net->ipv4.tcp_sk)
2796 return -ENOMEM;
2797
2798 for_each_possible_cpu(cpu) {
2799 struct sock *sk;
2800
2801 res = inet_ctl_sock_create(&sk, PF_INET, SOCK_RAW,
2802 IPPROTO_TCP, net);
2803 if (res)
2804 goto fail;
2805 sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
2806
2807 /* Please enforce IP_DF and IPID==0 for RST and
2808 * ACK sent in SYN-RECV and TIME-WAIT state.
2809 */
2810 inet_sk(sk)->pmtudisc = IP_PMTUDISC_DO;
2811
2812 *per_cpu_ptr(net->ipv4.tcp_sk, cpu) = sk;
2813 }
2814
2815 net->ipv4.sysctl_tcp_ecn = 2;
2816 net->ipv4.sysctl_tcp_ecn_fallback = 1;
2817
2818 net->ipv4.sysctl_tcp_base_mss = TCP_BASE_MSS;
2819 net->ipv4.sysctl_tcp_min_snd_mss = TCP_MIN_SND_MSS;
2820 net->ipv4.sysctl_tcp_probe_threshold = TCP_PROBE_THRESHOLD;
2821 net->ipv4.sysctl_tcp_probe_interval = TCP_PROBE_INTERVAL;
2822 net->ipv4.sysctl_tcp_mtu_probe_floor = TCP_MIN_SND_MSS;
2823
2824 net->ipv4.sysctl_tcp_keepalive_time = TCP_KEEPALIVE_TIME;
2825 net->ipv4.sysctl_tcp_keepalive_probes = TCP_KEEPALIVE_PROBES;
2826 net->ipv4.sysctl_tcp_keepalive_intvl = TCP_KEEPALIVE_INTVL;
2827
2828 net->ipv4.sysctl_tcp_syn_retries = TCP_SYN_RETRIES;
2829 net->ipv4.sysctl_tcp_synack_retries = TCP_SYNACK_RETRIES;
2830 net->ipv4.sysctl_tcp_syncookies = 1;
2831 net->ipv4.sysctl_tcp_reordering = TCP_FASTRETRANS_THRESH;
2832 net->ipv4.sysctl_tcp_retries1 = TCP_RETR1;
2833 net->ipv4.sysctl_tcp_retries2 = TCP_RETR2;
2834 net->ipv4.sysctl_tcp_orphan_retries = 0;
2835 net->ipv4.sysctl_tcp_fin_timeout = TCP_FIN_TIMEOUT;
2836 net->ipv4.sysctl_tcp_notsent_lowat = UINT_MAX;
2837 net->ipv4.sysctl_tcp_tw_reuse = 2;
2838 net->ipv4.sysctl_tcp_no_ssthresh_metrics_save = 1;
2839
2840 cnt = tcp_hashinfo.ehash_mask + 1;
2841 net->ipv4.tcp_death_row.sysctl_max_tw_buckets = cnt / 2;
2842 net->ipv4.tcp_death_row.hashinfo = &tcp_hashinfo;
2843
2844 net->ipv4.sysctl_max_syn_backlog = max(128, cnt / 128);
2845 net->ipv4.sysctl_tcp_sack = 1;
2846 net->ipv4.sysctl_tcp_window_scaling = 1;
2847 net->ipv4.sysctl_tcp_timestamps = 1;
2848 net->ipv4.sysctl_tcp_early_retrans = 3;
2849 net->ipv4.sysctl_tcp_recovery = TCP_RACK_LOSS_DETECTION;
2850 net->ipv4.sysctl_tcp_slow_start_after_idle = 1; /* By default, RFC2861 behavior. */
2851 net->ipv4.sysctl_tcp_retrans_collapse = 1;
2852 net->ipv4.sysctl_tcp_max_reordering = 300;
2853 net->ipv4.sysctl_tcp_dsack = 1;
2854 net->ipv4.sysctl_tcp_app_win = 31;
2855 net->ipv4.sysctl_tcp_adv_win_scale = 1;
2856 net->ipv4.sysctl_tcp_frto = 2;
2857 net->ipv4.sysctl_tcp_moderate_rcvbuf = 1;
2858 /* This limits the percentage of the congestion window which we
2859 * will allow a single TSO frame to consume. Building TSO frames
2860 * which are too large can cause TCP streams to be bursty.
2861 */
2862 net->ipv4.sysctl_tcp_tso_win_divisor = 3;
2863 /* Default TSQ limit of 16 TSO segments */
2864 net->ipv4.sysctl_tcp_limit_output_bytes = 16 * 65536;
2865 /* rfc5961 challenge ack rate limiting */
2866 net->ipv4.sysctl_tcp_challenge_ack_limit = 1000;
2867 net->ipv4.sysctl_tcp_min_tso_segs = 2;
2868 net->ipv4.sysctl_tcp_min_rtt_wlen = 300;
2869 net->ipv4.sysctl_tcp_autocorking = 1;
2870 net->ipv4.sysctl_tcp_invalid_ratelimit = HZ/2;
2871 net->ipv4.sysctl_tcp_pacing_ss_ratio = 200;
2872 net->ipv4.sysctl_tcp_pacing_ca_ratio = 120;
2873 if (net != &init_net) {
2874 memcpy(net->ipv4.sysctl_tcp_rmem,
2875 init_net.ipv4.sysctl_tcp_rmem,
2876 sizeof(init_net.ipv4.sysctl_tcp_rmem));
2877 memcpy(net->ipv4.sysctl_tcp_wmem,
2878 init_net.ipv4.sysctl_tcp_wmem,
2879 sizeof(init_net.ipv4.sysctl_tcp_wmem));
2880 }
2881 net->ipv4.sysctl_tcp_comp_sack_delay_ns = NSEC_PER_MSEC;
2882 net->ipv4.sysctl_tcp_comp_sack_slack_ns = 100 * NSEC_PER_USEC;
2883 net->ipv4.sysctl_tcp_comp_sack_nr = 44;
2884 net->ipv4.sysctl_tcp_fastopen = TFO_CLIENT_ENABLE;
2885 spin_lock_init(&net->ipv4.tcp_fastopen_ctx_lock);
2886 net->ipv4.sysctl_tcp_fastopen_blackhole_timeout = 60 * 60;
2887 atomic_set(&net->ipv4.tfo_active_disable_times, 0);
2888
2889 /* Reno is always built in */
2890 if (!net_eq(net, &init_net) &&
2891 bpf_try_module_get(init_net.ipv4.tcp_congestion_control,
2892 init_net.ipv4.tcp_congestion_control->owner))
2893 net->ipv4.tcp_congestion_control = init_net.ipv4.tcp_congestion_control;
2894 else
2895 net->ipv4.tcp_congestion_control = &tcp_reno;
2896
2897 return 0;
2898fail:
2899 tcp_sk_exit(net);
2900
2901 return res;
2902}
2903
2904static void __net_exit tcp_sk_exit_batch(struct list_head *net_exit_list)
2905{
2906 struct net *net;
2907
2908 inet_twsk_purge(&tcp_hashinfo, AF_INET);
2909
2910 list_for_each_entry(net, net_exit_list, exit_list)
2911 tcp_fastopen_ctx_destroy(net);
2912}
2913
2914static struct pernet_operations __net_initdata tcp_sk_ops = {
2915 .init = tcp_sk_init,
2916 .exit = tcp_sk_exit,
2917 .exit_batch = tcp_sk_exit_batch,
2918};
2919
2920#if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS)
2921DEFINE_BPF_ITER_FUNC(tcp, struct bpf_iter_meta *meta,
2922 struct sock_common *sk_common, uid_t uid)
2923
2924static int bpf_iter_init_tcp(void *priv_data, struct bpf_iter_aux_info *aux)
2925{
2926 struct tcp_iter_state *st = priv_data;
2927 struct tcp_seq_afinfo *afinfo;
2928 int ret;
2929
2930 afinfo = kmalloc(sizeof(*afinfo), GFP_USER | __GFP_NOWARN);
2931 if (!afinfo)
2932 return -ENOMEM;
2933
2934 afinfo->family = AF_UNSPEC;
2935 st->bpf_seq_afinfo = afinfo;
2936 ret = bpf_iter_init_seq_net(priv_data, aux);
2937 if (ret)
2938 kfree(afinfo);
2939 return ret;
2940}
2941
2942static void bpf_iter_fini_tcp(void *priv_data)
2943{
2944 struct tcp_iter_state *st = priv_data;
2945
2946 kfree(st->bpf_seq_afinfo);
2947 bpf_iter_fini_seq_net(priv_data);
2948}
2949
2950static const struct bpf_iter_seq_info tcp_seq_info = {
2951 .seq_ops = &bpf_iter_tcp_seq_ops,
2952 .init_seq_private = bpf_iter_init_tcp,
2953 .fini_seq_private = bpf_iter_fini_tcp,
2954 .seq_priv_size = sizeof(struct tcp_iter_state),
2955};
2956
2957static struct bpf_iter_reg tcp_reg_info = {
2958 .target = "tcp",
2959 .ctx_arg_info_size = 1,
2960 .ctx_arg_info = {
2961 { offsetof(struct bpf_iter__tcp, sk_common),
2962 PTR_TO_BTF_ID_OR_NULL },
2963 },
2964 .seq_info = &tcp_seq_info,
2965};
2966
2967static void __init bpf_iter_register(void)
2968{
2969 tcp_reg_info.ctx_arg_info[0].btf_id = btf_sock_ids[BTF_SOCK_TYPE_SOCK_COMMON];
2970 if (bpf_iter_reg_target(&tcp_reg_info))
2971 pr_warn("Warning: could not register bpf iterator tcp\n");
2972}
2973
2974#endif
2975
2976void __init tcp_v4_init(void)
2977{
2978 if (register_pernet_subsys(&tcp_sk_ops))
2979 panic("Failed to create the TCP control socket.\n");
2980
2981#if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS)
2982 bpf_iter_register();
2983#endif
2984}
1/*
2 * INET An implementation of the TCP/IP protocol suite for the LINUX
3 * operating system. INET is implemented using the BSD Socket
4 * interface as the means of communication with the user level.
5 *
6 * Implementation of the Transmission Control Protocol(TCP).
7 *
8 * IPv4 specific functions
9 *
10 *
11 * code split from:
12 * linux/ipv4/tcp.c
13 * linux/ipv4/tcp_input.c
14 * linux/ipv4/tcp_output.c
15 *
16 * See tcp.c for author information
17 *
18 * This program is free software; you can redistribute it and/or
19 * modify it under the terms of the GNU General Public License
20 * as published by the Free Software Foundation; either version
21 * 2 of the License, or (at your option) any later version.
22 */
23
24/*
25 * Changes:
26 * David S. Miller : New socket lookup architecture.
27 * This code is dedicated to John Dyson.
28 * David S. Miller : Change semantics of established hash,
29 * half is devoted to TIME_WAIT sockets
30 * and the rest go in the other half.
31 * Andi Kleen : Add support for syncookies and fixed
32 * some bugs: ip options weren't passed to
33 * the TCP layer, missed a check for an
34 * ACK bit.
35 * Andi Kleen : Implemented fast path mtu discovery.
36 * Fixed many serious bugs in the
37 * request_sock handling and moved
38 * most of it into the af independent code.
39 * Added tail drop and some other bugfixes.
40 * Added new listen semantics.
41 * Mike McLagan : Routing by source
42 * Juan Jose Ciarlante: ip_dynaddr bits
43 * Andi Kleen: various fixes.
44 * Vitaly E. Lavrov : Transparent proxy revived after year
45 * coma.
46 * Andi Kleen : Fix new listen.
47 * Andi Kleen : Fix accept error reporting.
48 * YOSHIFUJI Hideaki @USAGI and: Support IPV6_V6ONLY socket option, which
49 * Alexey Kuznetsov allow both IPv4 and IPv6 sockets to bind
50 * a single port at the same time.
51 */
52
53#define pr_fmt(fmt) "TCP: " fmt
54
55#include <linux/bottom_half.h>
56#include <linux/types.h>
57#include <linux/fcntl.h>
58#include <linux/module.h>
59#include <linux/random.h>
60#include <linux/cache.h>
61#include <linux/jhash.h>
62#include <linux/init.h>
63#include <linux/times.h>
64#include <linux/slab.h>
65
66#include <net/net_namespace.h>
67#include <net/icmp.h>
68#include <net/inet_hashtables.h>
69#include <net/tcp.h>
70#include <net/transp_v6.h>
71#include <net/ipv6.h>
72#include <net/inet_common.h>
73#include <net/timewait_sock.h>
74#include <net/xfrm.h>
75#include <net/secure_seq.h>
76#include <net/busy_poll.h>
77
78#include <linux/inet.h>
79#include <linux/ipv6.h>
80#include <linux/stddef.h>
81#include <linux/proc_fs.h>
82#include <linux/seq_file.h>
83
84#include <crypto/hash.h>
85#include <linux/scatterlist.h>
86
87int sysctl_tcp_tw_reuse __read_mostly;
88int sysctl_tcp_low_latency __read_mostly;
89EXPORT_SYMBOL(sysctl_tcp_low_latency);
90
91#ifdef CONFIG_TCP_MD5SIG
92static int tcp_v4_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key,
93 __be32 daddr, __be32 saddr, const struct tcphdr *th);
94#endif
95
96struct inet_hashinfo tcp_hashinfo;
97EXPORT_SYMBOL(tcp_hashinfo);
98
99static __u32 tcp_v4_init_sequence(const struct sk_buff *skb)
100{
101 return secure_tcp_sequence_number(ip_hdr(skb)->daddr,
102 ip_hdr(skb)->saddr,
103 tcp_hdr(skb)->dest,
104 tcp_hdr(skb)->source);
105}
106
107int tcp_twsk_unique(struct sock *sk, struct sock *sktw, void *twp)
108{
109 const struct tcp_timewait_sock *tcptw = tcp_twsk(sktw);
110 struct tcp_sock *tp = tcp_sk(sk);
111
112 /* With PAWS, it is safe from the viewpoint
113 of data integrity. Even without PAWS it is safe provided sequence
114 spaces do not overlap i.e. at data rates <= 80Mbit/sec.
115
116 Actually, the idea is close to VJ's one, only timestamp cache is
117 held not per host, but per port pair and TW bucket is used as state
118 holder.
119
120 If TW bucket has been already destroyed we fall back to VJ's scheme
121 and use initial timestamp retrieved from peer table.
122 */
123 if (tcptw->tw_ts_recent_stamp &&
124 (!twp || (sysctl_tcp_tw_reuse &&
125 get_seconds() - tcptw->tw_ts_recent_stamp > 1))) {
126 tp->write_seq = tcptw->tw_snd_nxt + 65535 + 2;
127 if (tp->write_seq == 0)
128 tp->write_seq = 1;
129 tp->rx_opt.ts_recent = tcptw->tw_ts_recent;
130 tp->rx_opt.ts_recent_stamp = tcptw->tw_ts_recent_stamp;
131 sock_hold(sktw);
132 return 1;
133 }
134
135 return 0;
136}
137EXPORT_SYMBOL_GPL(tcp_twsk_unique);
138
139/* This will initiate an outgoing connection. */
140int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
141{
142 struct sockaddr_in *usin = (struct sockaddr_in *)uaddr;
143 struct inet_sock *inet = inet_sk(sk);
144 struct tcp_sock *tp = tcp_sk(sk);
145 __be16 orig_sport, orig_dport;
146 __be32 daddr, nexthop;
147 struct flowi4 *fl4;
148 struct rtable *rt;
149 int err;
150 struct ip_options_rcu *inet_opt;
151
152 if (addr_len < sizeof(struct sockaddr_in))
153 return -EINVAL;
154
155 if (usin->sin_family != AF_INET)
156 return -EAFNOSUPPORT;
157
158 nexthop = daddr = usin->sin_addr.s_addr;
159 inet_opt = rcu_dereference_protected(inet->inet_opt,
160 sock_owned_by_user(sk));
161 if (inet_opt && inet_opt->opt.srr) {
162 if (!daddr)
163 return -EINVAL;
164 nexthop = inet_opt->opt.faddr;
165 }
166
167 orig_sport = inet->inet_sport;
168 orig_dport = usin->sin_port;
169 fl4 = &inet->cork.fl.u.ip4;
170 rt = ip_route_connect(fl4, nexthop, inet->inet_saddr,
171 RT_CONN_FLAGS(sk), sk->sk_bound_dev_if,
172 IPPROTO_TCP,
173 orig_sport, orig_dport, sk);
174 if (IS_ERR(rt)) {
175 err = PTR_ERR(rt);
176 if (err == -ENETUNREACH)
177 IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTNOROUTES);
178 return err;
179 }
180
181 if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) {
182 ip_rt_put(rt);
183 return -ENETUNREACH;
184 }
185
186 if (!inet_opt || !inet_opt->opt.srr)
187 daddr = fl4->daddr;
188
189 if (!inet->inet_saddr)
190 inet->inet_saddr = fl4->saddr;
191 sk_rcv_saddr_set(sk, inet->inet_saddr);
192
193 if (tp->rx_opt.ts_recent_stamp && inet->inet_daddr != daddr) {
194 /* Reset inherited state */
195 tp->rx_opt.ts_recent = 0;
196 tp->rx_opt.ts_recent_stamp = 0;
197 if (likely(!tp->repair))
198 tp->write_seq = 0;
199 }
200
201 if (tcp_death_row.sysctl_tw_recycle &&
202 !tp->rx_opt.ts_recent_stamp && fl4->daddr == daddr)
203 tcp_fetch_timewait_stamp(sk, &rt->dst);
204
205 inet->inet_dport = usin->sin_port;
206 sk_daddr_set(sk, daddr);
207
208 inet_csk(sk)->icsk_ext_hdr_len = 0;
209 if (inet_opt)
210 inet_csk(sk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
211
212 tp->rx_opt.mss_clamp = TCP_MSS_DEFAULT;
213
214 /* Socket identity is still unknown (sport may be zero).
215 * However we set state to SYN-SENT and not releasing socket
216 * lock select source port, enter ourselves into the hash tables and
217 * complete initialization after this.
218 */
219 tcp_set_state(sk, TCP_SYN_SENT);
220 err = inet_hash_connect(&tcp_death_row, sk);
221 if (err)
222 goto failure;
223
224 sk_set_txhash(sk);
225
226 rt = ip_route_newports(fl4, rt, orig_sport, orig_dport,
227 inet->inet_sport, inet->inet_dport, sk);
228 if (IS_ERR(rt)) {
229 err = PTR_ERR(rt);
230 rt = NULL;
231 goto failure;
232 }
233 /* OK, now commit destination to socket. */
234 sk->sk_gso_type = SKB_GSO_TCPV4;
235 sk_setup_caps(sk, &rt->dst);
236
237 if (!tp->write_seq && likely(!tp->repair))
238 tp->write_seq = secure_tcp_sequence_number(inet->inet_saddr,
239 inet->inet_daddr,
240 inet->inet_sport,
241 usin->sin_port);
242
243 inet->inet_id = tp->write_seq ^ jiffies;
244
245 err = tcp_connect(sk);
246
247 rt = NULL;
248 if (err)
249 goto failure;
250
251 return 0;
252
253failure:
254 /*
255 * This unhashes the socket and releases the local port,
256 * if necessary.
257 */
258 tcp_set_state(sk, TCP_CLOSE);
259 ip_rt_put(rt);
260 sk->sk_route_caps = 0;
261 inet->inet_dport = 0;
262 return err;
263}
264EXPORT_SYMBOL(tcp_v4_connect);
265
266/*
267 * This routine reacts to ICMP_FRAG_NEEDED mtu indications as defined in RFC1191.
268 * It can be called through tcp_release_cb() if socket was owned by user
269 * at the time tcp_v4_err() was called to handle ICMP message.
270 */
271void tcp_v4_mtu_reduced(struct sock *sk)
272{
273 struct dst_entry *dst;
274 struct inet_sock *inet = inet_sk(sk);
275 u32 mtu = tcp_sk(sk)->mtu_info;
276
277 dst = inet_csk_update_pmtu(sk, mtu);
278 if (!dst)
279 return;
280
281 /* Something is about to be wrong... Remember soft error
282 * for the case, if this connection will not able to recover.
283 */
284 if (mtu < dst_mtu(dst) && ip_dont_fragment(sk, dst))
285 sk->sk_err_soft = EMSGSIZE;
286
287 mtu = dst_mtu(dst);
288
289 if (inet->pmtudisc != IP_PMTUDISC_DONT &&
290 ip_sk_accept_pmtu(sk) &&
291 inet_csk(sk)->icsk_pmtu_cookie > mtu) {
292 tcp_sync_mss(sk, mtu);
293
294 /* Resend the TCP packet because it's
295 * clear that the old packet has been
296 * dropped. This is the new "fast" path mtu
297 * discovery.
298 */
299 tcp_simple_retransmit(sk);
300 } /* else let the usual retransmit timer handle it */
301}
302EXPORT_SYMBOL(tcp_v4_mtu_reduced);
303
304static void do_redirect(struct sk_buff *skb, struct sock *sk)
305{
306 struct dst_entry *dst = __sk_dst_check(sk, 0);
307
308 if (dst)
309 dst->ops->redirect(dst, sk, skb);
310}
311
312
313/* handle ICMP messages on TCP_NEW_SYN_RECV request sockets */
314void tcp_req_err(struct sock *sk, u32 seq, bool abort)
315{
316 struct request_sock *req = inet_reqsk(sk);
317 struct net *net = sock_net(sk);
318
319 /* ICMPs are not backlogged, hence we cannot get
320 * an established socket here.
321 */
322 if (seq != tcp_rsk(req)->snt_isn) {
323 NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
324 } else if (abort) {
325 /*
326 * Still in SYN_RECV, just remove it silently.
327 * There is no good way to pass the error to the newly
328 * created socket, and POSIX does not want network
329 * errors returned from accept().
330 */
331 inet_csk_reqsk_queue_drop(req->rsk_listener, req);
332 NET_INC_STATS_BH(net, LINUX_MIB_LISTENDROPS);
333 }
334 reqsk_put(req);
335}
336EXPORT_SYMBOL(tcp_req_err);
337
338/*
339 * This routine is called by the ICMP module when it gets some
340 * sort of error condition. If err < 0 then the socket should
341 * be closed and the error returned to the user. If err > 0
342 * it's just the icmp type << 8 | icmp code. After adjustment
343 * header points to the first 8 bytes of the tcp header. We need
344 * to find the appropriate port.
345 *
346 * The locking strategy used here is very "optimistic". When
347 * someone else accesses the socket the ICMP is just dropped
348 * and for some paths there is no check at all.
349 * A more general error queue to queue errors for later handling
350 * is probably better.
351 *
352 */
353
354void tcp_v4_err(struct sk_buff *icmp_skb, u32 info)
355{
356 const struct iphdr *iph = (const struct iphdr *)icmp_skb->data;
357 struct tcphdr *th = (struct tcphdr *)(icmp_skb->data + (iph->ihl << 2));
358 struct inet_connection_sock *icsk;
359 struct tcp_sock *tp;
360 struct inet_sock *inet;
361 const int type = icmp_hdr(icmp_skb)->type;
362 const int code = icmp_hdr(icmp_skb)->code;
363 struct sock *sk;
364 struct sk_buff *skb;
365 struct request_sock *fastopen;
366 __u32 seq, snd_una;
367 __u32 remaining;
368 int err;
369 struct net *net = dev_net(icmp_skb->dev);
370
371 sk = __inet_lookup_established(net, &tcp_hashinfo, iph->daddr,
372 th->dest, iph->saddr, ntohs(th->source),
373 inet_iif(icmp_skb));
374 if (!sk) {
375 ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS);
376 return;
377 }
378 if (sk->sk_state == TCP_TIME_WAIT) {
379 inet_twsk_put(inet_twsk(sk));
380 return;
381 }
382 seq = ntohl(th->seq);
383 if (sk->sk_state == TCP_NEW_SYN_RECV)
384 return tcp_req_err(sk, seq,
385 type == ICMP_PARAMETERPROB ||
386 type == ICMP_TIME_EXCEEDED ||
387 (type == ICMP_DEST_UNREACH &&
388 (code == ICMP_NET_UNREACH ||
389 code == ICMP_HOST_UNREACH)));
390
391 bh_lock_sock(sk);
392 /* If too many ICMPs get dropped on busy
393 * servers this needs to be solved differently.
394 * We do take care of PMTU discovery (RFC1191) special case :
395 * we can receive locally generated ICMP messages while socket is held.
396 */
397 if (sock_owned_by_user(sk)) {
398 if (!(type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED))
399 NET_INC_STATS_BH(net, LINUX_MIB_LOCKDROPPEDICMPS);
400 }
401 if (sk->sk_state == TCP_CLOSE)
402 goto out;
403
404 if (unlikely(iph->ttl < inet_sk(sk)->min_ttl)) {
405 NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP);
406 goto out;
407 }
408
409 icsk = inet_csk(sk);
410 tp = tcp_sk(sk);
411 /* XXX (TFO) - tp->snd_una should be ISN (tcp_create_openreq_child() */
412 fastopen = tp->fastopen_rsk;
413 snd_una = fastopen ? tcp_rsk(fastopen)->snt_isn : tp->snd_una;
414 if (sk->sk_state != TCP_LISTEN &&
415 !between(seq, snd_una, tp->snd_nxt)) {
416 NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
417 goto out;
418 }
419
420 switch (type) {
421 case ICMP_REDIRECT:
422 do_redirect(icmp_skb, sk);
423 goto out;
424 case ICMP_SOURCE_QUENCH:
425 /* Just silently ignore these. */
426 goto out;
427 case ICMP_PARAMETERPROB:
428 err = EPROTO;
429 break;
430 case ICMP_DEST_UNREACH:
431 if (code > NR_ICMP_UNREACH)
432 goto out;
433
434 if (code == ICMP_FRAG_NEEDED) { /* PMTU discovery (RFC1191) */
435 /* We are not interested in TCP_LISTEN and open_requests
436 * (SYN-ACKs send out by Linux are always <576bytes so
437 * they should go through unfragmented).
438 */
439 if (sk->sk_state == TCP_LISTEN)
440 goto out;
441
442 tp->mtu_info = info;
443 if (!sock_owned_by_user(sk)) {
444 tcp_v4_mtu_reduced(sk);
445 } else {
446 if (!test_and_set_bit(TCP_MTU_REDUCED_DEFERRED, &tp->tsq_flags))
447 sock_hold(sk);
448 }
449 goto out;
450 }
451
452 err = icmp_err_convert[code].errno;
453 /* check if icmp_skb allows revert of backoff
454 * (see draft-zimmermann-tcp-lcd) */
455 if (code != ICMP_NET_UNREACH && code != ICMP_HOST_UNREACH)
456 break;
457 if (seq != tp->snd_una || !icsk->icsk_retransmits ||
458 !icsk->icsk_backoff || fastopen)
459 break;
460
461 if (sock_owned_by_user(sk))
462 break;
463
464 icsk->icsk_backoff--;
465 icsk->icsk_rto = tp->srtt_us ? __tcp_set_rto(tp) :
466 TCP_TIMEOUT_INIT;
467 icsk->icsk_rto = inet_csk_rto_backoff(icsk, TCP_RTO_MAX);
468
469 skb = tcp_write_queue_head(sk);
470 BUG_ON(!skb);
471
472 remaining = icsk->icsk_rto -
473 min(icsk->icsk_rto,
474 tcp_time_stamp - tcp_skb_timestamp(skb));
475
476 if (remaining) {
477 inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
478 remaining, TCP_RTO_MAX);
479 } else {
480 /* RTO revert clocked out retransmission.
481 * Will retransmit now */
482 tcp_retransmit_timer(sk);
483 }
484
485 break;
486 case ICMP_TIME_EXCEEDED:
487 err = EHOSTUNREACH;
488 break;
489 default:
490 goto out;
491 }
492
493 switch (sk->sk_state) {
494 case TCP_SYN_SENT:
495 case TCP_SYN_RECV:
496 /* Only in fast or simultaneous open. If a fast open socket is
497 * is already accepted it is treated as a connected one below.
498 */
499 if (fastopen && !fastopen->sk)
500 break;
501
502 if (!sock_owned_by_user(sk)) {
503 sk->sk_err = err;
504
505 sk->sk_error_report(sk);
506
507 tcp_done(sk);
508 } else {
509 sk->sk_err_soft = err;
510 }
511 goto out;
512 }
513
514 /* If we've already connected we will keep trying
515 * until we time out, or the user gives up.
516 *
517 * rfc1122 4.2.3.9 allows to consider as hard errors
518 * only PROTO_UNREACH and PORT_UNREACH (well, FRAG_FAILED too,
519 * but it is obsoleted by pmtu discovery).
520 *
521 * Note, that in modern internet, where routing is unreliable
522 * and in each dark corner broken firewalls sit, sending random
523 * errors ordered by their masters even this two messages finally lose
524 * their original sense (even Linux sends invalid PORT_UNREACHs)
525 *
526 * Now we are in compliance with RFCs.
527 * --ANK (980905)
528 */
529
530 inet = inet_sk(sk);
531 if (!sock_owned_by_user(sk) && inet->recverr) {
532 sk->sk_err = err;
533 sk->sk_error_report(sk);
534 } else { /* Only an error on timeout */
535 sk->sk_err_soft = err;
536 }
537
538out:
539 bh_unlock_sock(sk);
540 sock_put(sk);
541}
542
543void __tcp_v4_send_check(struct sk_buff *skb, __be32 saddr, __be32 daddr)
544{
545 struct tcphdr *th = tcp_hdr(skb);
546
547 if (skb->ip_summed == CHECKSUM_PARTIAL) {
548 th->check = ~tcp_v4_check(skb->len, saddr, daddr, 0);
549 skb->csum_start = skb_transport_header(skb) - skb->head;
550 skb->csum_offset = offsetof(struct tcphdr, check);
551 } else {
552 th->check = tcp_v4_check(skb->len, saddr, daddr,
553 csum_partial(th,
554 th->doff << 2,
555 skb->csum));
556 }
557}
558
559/* This routine computes an IPv4 TCP checksum. */
560void tcp_v4_send_check(struct sock *sk, struct sk_buff *skb)
561{
562 const struct inet_sock *inet = inet_sk(sk);
563
564 __tcp_v4_send_check(skb, inet->inet_saddr, inet->inet_daddr);
565}
566EXPORT_SYMBOL(tcp_v4_send_check);
567
568/*
569 * This routine will send an RST to the other tcp.
570 *
571 * Someone asks: why I NEVER use socket parameters (TOS, TTL etc.)
572 * for reset.
573 * Answer: if a packet caused RST, it is not for a socket
574 * existing in our system, if it is matched to a socket,
575 * it is just duplicate segment or bug in other side's TCP.
576 * So that we build reply only basing on parameters
577 * arrived with segment.
578 * Exception: precedence violation. We do not implement it in any case.
579 */
580
581static void tcp_v4_send_reset(const struct sock *sk, struct sk_buff *skb)
582{
583 const struct tcphdr *th = tcp_hdr(skb);
584 struct {
585 struct tcphdr th;
586#ifdef CONFIG_TCP_MD5SIG
587 __be32 opt[(TCPOLEN_MD5SIG_ALIGNED >> 2)];
588#endif
589 } rep;
590 struct ip_reply_arg arg;
591#ifdef CONFIG_TCP_MD5SIG
592 struct tcp_md5sig_key *key = NULL;
593 const __u8 *hash_location = NULL;
594 unsigned char newhash[16];
595 int genhash;
596 struct sock *sk1 = NULL;
597#endif
598 struct net *net;
599
600 /* Never send a reset in response to a reset. */
601 if (th->rst)
602 return;
603
604 /* If sk not NULL, it means we did a successful lookup and incoming
605 * route had to be correct. prequeue might have dropped our dst.
606 */
607 if (!sk && skb_rtable(skb)->rt_type != RTN_LOCAL)
608 return;
609
610 /* Swap the send and the receive. */
611 memset(&rep, 0, sizeof(rep));
612 rep.th.dest = th->source;
613 rep.th.source = th->dest;
614 rep.th.doff = sizeof(struct tcphdr) / 4;
615 rep.th.rst = 1;
616
617 if (th->ack) {
618 rep.th.seq = th->ack_seq;
619 } else {
620 rep.th.ack = 1;
621 rep.th.ack_seq = htonl(ntohl(th->seq) + th->syn + th->fin +
622 skb->len - (th->doff << 2));
623 }
624
625 memset(&arg, 0, sizeof(arg));
626 arg.iov[0].iov_base = (unsigned char *)&rep;
627 arg.iov[0].iov_len = sizeof(rep.th);
628
629 net = sk ? sock_net(sk) : dev_net(skb_dst(skb)->dev);
630#ifdef CONFIG_TCP_MD5SIG
631 hash_location = tcp_parse_md5sig_option(th);
632 if (sk && sk_fullsock(sk)) {
633 key = tcp_md5_do_lookup(sk, (union tcp_md5_addr *)
634 &ip_hdr(skb)->saddr, AF_INET);
635 } else if (hash_location) {
636 /*
637 * active side is lost. Try to find listening socket through
638 * source port, and then find md5 key through listening socket.
639 * we are not loose security here:
640 * Incoming packet is checked with md5 hash with finding key,
641 * no RST generated if md5 hash doesn't match.
642 */
643 sk1 = __inet_lookup_listener(net, &tcp_hashinfo, NULL, 0,
644 ip_hdr(skb)->saddr,
645 th->source, ip_hdr(skb)->daddr,
646 ntohs(th->source), inet_iif(skb));
647 /* don't send rst if it can't find key */
648 if (!sk1)
649 return;
650 rcu_read_lock();
651 key = tcp_md5_do_lookup(sk1, (union tcp_md5_addr *)
652 &ip_hdr(skb)->saddr, AF_INET);
653 if (!key)
654 goto release_sk1;
655
656 genhash = tcp_v4_md5_hash_skb(newhash, key, NULL, skb);
657 if (genhash || memcmp(hash_location, newhash, 16) != 0)
658 goto release_sk1;
659 }
660
661 if (key) {
662 rep.opt[0] = htonl((TCPOPT_NOP << 24) |
663 (TCPOPT_NOP << 16) |
664 (TCPOPT_MD5SIG << 8) |
665 TCPOLEN_MD5SIG);
666 /* Update length and the length the header thinks exists */
667 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED;
668 rep.th.doff = arg.iov[0].iov_len / 4;
669
670 tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[1],
671 key, ip_hdr(skb)->saddr,
672 ip_hdr(skb)->daddr, &rep.th);
673 }
674#endif
675 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
676 ip_hdr(skb)->saddr, /* XXX */
677 arg.iov[0].iov_len, IPPROTO_TCP, 0);
678 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
679 arg.flags = (sk && inet_sk_transparent(sk)) ? IP_REPLY_ARG_NOSRCCHECK : 0;
680
681 /* When socket is gone, all binding information is lost.
682 * routing might fail in this case. No choice here, if we choose to force
683 * input interface, we will misroute in case of asymmetric route.
684 */
685 if (sk)
686 arg.bound_dev_if = sk->sk_bound_dev_if;
687
688 BUILD_BUG_ON(offsetof(struct sock, sk_bound_dev_if) !=
689 offsetof(struct inet_timewait_sock, tw_bound_dev_if));
690
691 arg.tos = ip_hdr(skb)->tos;
692 ip_send_unicast_reply(*this_cpu_ptr(net->ipv4.tcp_sk),
693 skb, &TCP_SKB_CB(skb)->header.h4.opt,
694 ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
695 &arg, arg.iov[0].iov_len);
696
697 TCP_INC_STATS_BH(net, TCP_MIB_OUTSEGS);
698 TCP_INC_STATS_BH(net, TCP_MIB_OUTRSTS);
699
700#ifdef CONFIG_TCP_MD5SIG
701release_sk1:
702 if (sk1) {
703 rcu_read_unlock();
704 sock_put(sk1);
705 }
706#endif
707}
708
709/* The code following below sending ACKs in SYN-RECV and TIME-WAIT states
710 outside socket context is ugly, certainly. What can I do?
711 */
712
713static void tcp_v4_send_ack(struct net *net,
714 struct sk_buff *skb, u32 seq, u32 ack,
715 u32 win, u32 tsval, u32 tsecr, int oif,
716 struct tcp_md5sig_key *key,
717 int reply_flags, u8 tos)
718{
719 const struct tcphdr *th = tcp_hdr(skb);
720 struct {
721 struct tcphdr th;
722 __be32 opt[(TCPOLEN_TSTAMP_ALIGNED >> 2)
723#ifdef CONFIG_TCP_MD5SIG
724 + (TCPOLEN_MD5SIG_ALIGNED >> 2)
725#endif
726 ];
727 } rep;
728 struct ip_reply_arg arg;
729
730 memset(&rep.th, 0, sizeof(struct tcphdr));
731 memset(&arg, 0, sizeof(arg));
732
733 arg.iov[0].iov_base = (unsigned char *)&rep;
734 arg.iov[0].iov_len = sizeof(rep.th);
735 if (tsecr) {
736 rep.opt[0] = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
737 (TCPOPT_TIMESTAMP << 8) |
738 TCPOLEN_TIMESTAMP);
739 rep.opt[1] = htonl(tsval);
740 rep.opt[2] = htonl(tsecr);
741 arg.iov[0].iov_len += TCPOLEN_TSTAMP_ALIGNED;
742 }
743
744 /* Swap the send and the receive. */
745 rep.th.dest = th->source;
746 rep.th.source = th->dest;
747 rep.th.doff = arg.iov[0].iov_len / 4;
748 rep.th.seq = htonl(seq);
749 rep.th.ack_seq = htonl(ack);
750 rep.th.ack = 1;
751 rep.th.window = htons(win);
752
753#ifdef CONFIG_TCP_MD5SIG
754 if (key) {
755 int offset = (tsecr) ? 3 : 0;
756
757 rep.opt[offset++] = htonl((TCPOPT_NOP << 24) |
758 (TCPOPT_NOP << 16) |
759 (TCPOPT_MD5SIG << 8) |
760 TCPOLEN_MD5SIG);
761 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED;
762 rep.th.doff = arg.iov[0].iov_len/4;
763
764 tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[offset],
765 key, ip_hdr(skb)->saddr,
766 ip_hdr(skb)->daddr, &rep.th);
767 }
768#endif
769 arg.flags = reply_flags;
770 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
771 ip_hdr(skb)->saddr, /* XXX */
772 arg.iov[0].iov_len, IPPROTO_TCP, 0);
773 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
774 if (oif)
775 arg.bound_dev_if = oif;
776 arg.tos = tos;
777 ip_send_unicast_reply(*this_cpu_ptr(net->ipv4.tcp_sk),
778 skb, &TCP_SKB_CB(skb)->header.h4.opt,
779 ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
780 &arg, arg.iov[0].iov_len);
781
782 TCP_INC_STATS_BH(net, TCP_MIB_OUTSEGS);
783}
784
785static void tcp_v4_timewait_ack(struct sock *sk, struct sk_buff *skb)
786{
787 struct inet_timewait_sock *tw = inet_twsk(sk);
788 struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
789
790 tcp_v4_send_ack(sock_net(sk), skb,
791 tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
792 tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
793 tcp_time_stamp + tcptw->tw_ts_offset,
794 tcptw->tw_ts_recent,
795 tw->tw_bound_dev_if,
796 tcp_twsk_md5_key(tcptw),
797 tw->tw_transparent ? IP_REPLY_ARG_NOSRCCHECK : 0,
798 tw->tw_tos
799 );
800
801 inet_twsk_put(tw);
802}
803
804static void tcp_v4_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb,
805 struct request_sock *req)
806{
807 /* sk->sk_state == TCP_LISTEN -> for regular TCP_SYN_RECV
808 * sk->sk_state == TCP_SYN_RECV -> for Fast Open.
809 */
810 u32 seq = (sk->sk_state == TCP_LISTEN) ? tcp_rsk(req)->snt_isn + 1 :
811 tcp_sk(sk)->snd_nxt;
812
813 tcp_v4_send_ack(sock_net(sk), skb, seq,
814 tcp_rsk(req)->rcv_nxt, req->rsk_rcv_wnd,
815 tcp_time_stamp,
816 req->ts_recent,
817 0,
818 tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&ip_hdr(skb)->daddr,
819 AF_INET),
820 inet_rsk(req)->no_srccheck ? IP_REPLY_ARG_NOSRCCHECK : 0,
821 ip_hdr(skb)->tos);
822}
823
824/*
825 * Send a SYN-ACK after having received a SYN.
826 * This still operates on a request_sock only, not on a big
827 * socket.
828 */
829static int tcp_v4_send_synack(const struct sock *sk, struct dst_entry *dst,
830 struct flowi *fl,
831 struct request_sock *req,
832 struct tcp_fastopen_cookie *foc,
833 bool attach_req)
834{
835 const struct inet_request_sock *ireq = inet_rsk(req);
836 struct flowi4 fl4;
837 int err = -1;
838 struct sk_buff *skb;
839
840 /* First, grab a route. */
841 if (!dst && (dst = inet_csk_route_req(sk, &fl4, req)) == NULL)
842 return -1;
843
844 skb = tcp_make_synack(sk, dst, req, foc, attach_req);
845
846 if (skb) {
847 __tcp_v4_send_check(skb, ireq->ir_loc_addr, ireq->ir_rmt_addr);
848
849 err = ip_build_and_send_pkt(skb, sk, ireq->ir_loc_addr,
850 ireq->ir_rmt_addr,
851 ireq->opt);
852 err = net_xmit_eval(err);
853 }
854
855 return err;
856}
857
858/*
859 * IPv4 request_sock destructor.
860 */
861static void tcp_v4_reqsk_destructor(struct request_sock *req)
862{
863 kfree(inet_rsk(req)->opt);
864}
865
866#ifdef CONFIG_TCP_MD5SIG
867/*
868 * RFC2385 MD5 checksumming requires a mapping of
869 * IP address->MD5 Key.
870 * We need to maintain these in the sk structure.
871 */
872
873/* Find the Key structure for an address. */
874struct tcp_md5sig_key *tcp_md5_do_lookup(const struct sock *sk,
875 const union tcp_md5_addr *addr,
876 int family)
877{
878 const struct tcp_sock *tp = tcp_sk(sk);
879 struct tcp_md5sig_key *key;
880 unsigned int size = sizeof(struct in_addr);
881 const struct tcp_md5sig_info *md5sig;
882
883 /* caller either holds rcu_read_lock() or socket lock */
884 md5sig = rcu_dereference_check(tp->md5sig_info,
885 sock_owned_by_user(sk) ||
886 lockdep_is_held((spinlock_t *)&sk->sk_lock.slock));
887 if (!md5sig)
888 return NULL;
889#if IS_ENABLED(CONFIG_IPV6)
890 if (family == AF_INET6)
891 size = sizeof(struct in6_addr);
892#endif
893 hlist_for_each_entry_rcu(key, &md5sig->head, node) {
894 if (key->family != family)
895 continue;
896 if (!memcmp(&key->addr, addr, size))
897 return key;
898 }
899 return NULL;
900}
901EXPORT_SYMBOL(tcp_md5_do_lookup);
902
903struct tcp_md5sig_key *tcp_v4_md5_lookup(const struct sock *sk,
904 const struct sock *addr_sk)
905{
906 const union tcp_md5_addr *addr;
907
908 addr = (const union tcp_md5_addr *)&addr_sk->sk_daddr;
909 return tcp_md5_do_lookup(sk, addr, AF_INET);
910}
911EXPORT_SYMBOL(tcp_v4_md5_lookup);
912
913/* This can be called on a newly created socket, from other files */
914int tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr,
915 int family, const u8 *newkey, u8 newkeylen, gfp_t gfp)
916{
917 /* Add Key to the list */
918 struct tcp_md5sig_key *key;
919 struct tcp_sock *tp = tcp_sk(sk);
920 struct tcp_md5sig_info *md5sig;
921
922 key = tcp_md5_do_lookup(sk, addr, family);
923 if (key) {
924 /* Pre-existing entry - just update that one. */
925 memcpy(key->key, newkey, newkeylen);
926 key->keylen = newkeylen;
927 return 0;
928 }
929
930 md5sig = rcu_dereference_protected(tp->md5sig_info,
931 sock_owned_by_user(sk) ||
932 lockdep_is_held(&sk->sk_lock.slock));
933 if (!md5sig) {
934 md5sig = kmalloc(sizeof(*md5sig), gfp);
935 if (!md5sig)
936 return -ENOMEM;
937
938 sk_nocaps_add(sk, NETIF_F_GSO_MASK);
939 INIT_HLIST_HEAD(&md5sig->head);
940 rcu_assign_pointer(tp->md5sig_info, md5sig);
941 }
942
943 key = sock_kmalloc(sk, sizeof(*key), gfp);
944 if (!key)
945 return -ENOMEM;
946 if (!tcp_alloc_md5sig_pool()) {
947 sock_kfree_s(sk, key, sizeof(*key));
948 return -ENOMEM;
949 }
950
951 memcpy(key->key, newkey, newkeylen);
952 key->keylen = newkeylen;
953 key->family = family;
954 memcpy(&key->addr, addr,
955 (family == AF_INET6) ? sizeof(struct in6_addr) :
956 sizeof(struct in_addr));
957 hlist_add_head_rcu(&key->node, &md5sig->head);
958 return 0;
959}
960EXPORT_SYMBOL(tcp_md5_do_add);
961
962int tcp_md5_do_del(struct sock *sk, const union tcp_md5_addr *addr, int family)
963{
964 struct tcp_md5sig_key *key;
965
966 key = tcp_md5_do_lookup(sk, addr, family);
967 if (!key)
968 return -ENOENT;
969 hlist_del_rcu(&key->node);
970 atomic_sub(sizeof(*key), &sk->sk_omem_alloc);
971 kfree_rcu(key, rcu);
972 return 0;
973}
974EXPORT_SYMBOL(tcp_md5_do_del);
975
976static void tcp_clear_md5_list(struct sock *sk)
977{
978 struct tcp_sock *tp = tcp_sk(sk);
979 struct tcp_md5sig_key *key;
980 struct hlist_node *n;
981 struct tcp_md5sig_info *md5sig;
982
983 md5sig = rcu_dereference_protected(tp->md5sig_info, 1);
984
985 hlist_for_each_entry_safe(key, n, &md5sig->head, node) {
986 hlist_del_rcu(&key->node);
987 atomic_sub(sizeof(*key), &sk->sk_omem_alloc);
988 kfree_rcu(key, rcu);
989 }
990}
991
992static int tcp_v4_parse_md5_keys(struct sock *sk, char __user *optval,
993 int optlen)
994{
995 struct tcp_md5sig cmd;
996 struct sockaddr_in *sin = (struct sockaddr_in *)&cmd.tcpm_addr;
997
998 if (optlen < sizeof(cmd))
999 return -EINVAL;
1000
1001 if (copy_from_user(&cmd, optval, sizeof(cmd)))
1002 return -EFAULT;
1003
1004 if (sin->sin_family != AF_INET)
1005 return -EINVAL;
1006
1007 if (!cmd.tcpm_keylen)
1008 return tcp_md5_do_del(sk, (union tcp_md5_addr *)&sin->sin_addr.s_addr,
1009 AF_INET);
1010
1011 if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN)
1012 return -EINVAL;
1013
1014 return tcp_md5_do_add(sk, (union tcp_md5_addr *)&sin->sin_addr.s_addr,
1015 AF_INET, cmd.tcpm_key, cmd.tcpm_keylen,
1016 GFP_KERNEL);
1017}
1018
1019static int tcp_v4_md5_hash_pseudoheader(struct tcp_md5sig_pool *hp,
1020 __be32 daddr, __be32 saddr, int nbytes)
1021{
1022 struct tcp4_pseudohdr *bp;
1023 struct scatterlist sg;
1024
1025 bp = &hp->md5_blk.ip4;
1026
1027 /*
1028 * 1. the TCP pseudo-header (in the order: source IP address,
1029 * destination IP address, zero-padded protocol number, and
1030 * segment length)
1031 */
1032 bp->saddr = saddr;
1033 bp->daddr = daddr;
1034 bp->pad = 0;
1035 bp->protocol = IPPROTO_TCP;
1036 bp->len = cpu_to_be16(nbytes);
1037
1038 sg_init_one(&sg, bp, sizeof(*bp));
1039 ahash_request_set_crypt(hp->md5_req, &sg, NULL, sizeof(*bp));
1040 return crypto_ahash_update(hp->md5_req);
1041}
1042
1043static int tcp_v4_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key,
1044 __be32 daddr, __be32 saddr, const struct tcphdr *th)
1045{
1046 struct tcp_md5sig_pool *hp;
1047 struct ahash_request *req;
1048
1049 hp = tcp_get_md5sig_pool();
1050 if (!hp)
1051 goto clear_hash_noput;
1052 req = hp->md5_req;
1053
1054 if (crypto_ahash_init(req))
1055 goto clear_hash;
1056 if (tcp_v4_md5_hash_pseudoheader(hp, daddr, saddr, th->doff << 2))
1057 goto clear_hash;
1058 if (tcp_md5_hash_header(hp, th))
1059 goto clear_hash;
1060 if (tcp_md5_hash_key(hp, key))
1061 goto clear_hash;
1062 ahash_request_set_crypt(req, NULL, md5_hash, 0);
1063 if (crypto_ahash_final(req))
1064 goto clear_hash;
1065
1066 tcp_put_md5sig_pool();
1067 return 0;
1068
1069clear_hash:
1070 tcp_put_md5sig_pool();
1071clear_hash_noput:
1072 memset(md5_hash, 0, 16);
1073 return 1;
1074}
1075
1076int tcp_v4_md5_hash_skb(char *md5_hash, const struct tcp_md5sig_key *key,
1077 const struct sock *sk,
1078 const struct sk_buff *skb)
1079{
1080 struct tcp_md5sig_pool *hp;
1081 struct ahash_request *req;
1082 const struct tcphdr *th = tcp_hdr(skb);
1083 __be32 saddr, daddr;
1084
1085 if (sk) { /* valid for establish/request sockets */
1086 saddr = sk->sk_rcv_saddr;
1087 daddr = sk->sk_daddr;
1088 } else {
1089 const struct iphdr *iph = ip_hdr(skb);
1090 saddr = iph->saddr;
1091 daddr = iph->daddr;
1092 }
1093
1094 hp = tcp_get_md5sig_pool();
1095 if (!hp)
1096 goto clear_hash_noput;
1097 req = hp->md5_req;
1098
1099 if (crypto_ahash_init(req))
1100 goto clear_hash;
1101
1102 if (tcp_v4_md5_hash_pseudoheader(hp, daddr, saddr, skb->len))
1103 goto clear_hash;
1104 if (tcp_md5_hash_header(hp, th))
1105 goto clear_hash;
1106 if (tcp_md5_hash_skb_data(hp, skb, th->doff << 2))
1107 goto clear_hash;
1108 if (tcp_md5_hash_key(hp, key))
1109 goto clear_hash;
1110 ahash_request_set_crypt(req, NULL, md5_hash, 0);
1111 if (crypto_ahash_final(req))
1112 goto clear_hash;
1113
1114 tcp_put_md5sig_pool();
1115 return 0;
1116
1117clear_hash:
1118 tcp_put_md5sig_pool();
1119clear_hash_noput:
1120 memset(md5_hash, 0, 16);
1121 return 1;
1122}
1123EXPORT_SYMBOL(tcp_v4_md5_hash_skb);
1124
1125#endif
1126
1127/* Called with rcu_read_lock() */
1128static bool tcp_v4_inbound_md5_hash(const struct sock *sk,
1129 const struct sk_buff *skb)
1130{
1131#ifdef CONFIG_TCP_MD5SIG
1132 /*
1133 * This gets called for each TCP segment that arrives
1134 * so we want to be efficient.
1135 * We have 3 drop cases:
1136 * o No MD5 hash and one expected.
1137 * o MD5 hash and we're not expecting one.
1138 * o MD5 hash and its wrong.
1139 */
1140 const __u8 *hash_location = NULL;
1141 struct tcp_md5sig_key *hash_expected;
1142 const struct iphdr *iph = ip_hdr(skb);
1143 const struct tcphdr *th = tcp_hdr(skb);
1144 int genhash;
1145 unsigned char newhash[16];
1146
1147 hash_expected = tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&iph->saddr,
1148 AF_INET);
1149 hash_location = tcp_parse_md5sig_option(th);
1150
1151 /* We've parsed the options - do we have a hash? */
1152 if (!hash_expected && !hash_location)
1153 return false;
1154
1155 if (hash_expected && !hash_location) {
1156 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5NOTFOUND);
1157 return true;
1158 }
1159
1160 if (!hash_expected && hash_location) {
1161 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5UNEXPECTED);
1162 return true;
1163 }
1164
1165 /* Okay, so this is hash_expected and hash_location -
1166 * so we need to calculate the checksum.
1167 */
1168 genhash = tcp_v4_md5_hash_skb(newhash,
1169 hash_expected,
1170 NULL, skb);
1171
1172 if (genhash || memcmp(hash_location, newhash, 16) != 0) {
1173 net_info_ratelimited("MD5 Hash failed for (%pI4, %d)->(%pI4, %d)%s\n",
1174 &iph->saddr, ntohs(th->source),
1175 &iph->daddr, ntohs(th->dest),
1176 genhash ? " tcp_v4_calc_md5_hash failed"
1177 : "");
1178 return true;
1179 }
1180 return false;
1181#endif
1182 return false;
1183}
1184
1185static void tcp_v4_init_req(struct request_sock *req,
1186 const struct sock *sk_listener,
1187 struct sk_buff *skb)
1188{
1189 struct inet_request_sock *ireq = inet_rsk(req);
1190
1191 sk_rcv_saddr_set(req_to_sk(req), ip_hdr(skb)->daddr);
1192 sk_daddr_set(req_to_sk(req), ip_hdr(skb)->saddr);
1193 ireq->no_srccheck = inet_sk(sk_listener)->transparent;
1194 ireq->opt = tcp_v4_save_options(skb);
1195}
1196
1197static struct dst_entry *tcp_v4_route_req(const struct sock *sk,
1198 struct flowi *fl,
1199 const struct request_sock *req,
1200 bool *strict)
1201{
1202 struct dst_entry *dst = inet_csk_route_req(sk, &fl->u.ip4, req);
1203
1204 if (strict) {
1205 if (fl->u.ip4.daddr == inet_rsk(req)->ir_rmt_addr)
1206 *strict = true;
1207 else
1208 *strict = false;
1209 }
1210
1211 return dst;
1212}
1213
1214struct request_sock_ops tcp_request_sock_ops __read_mostly = {
1215 .family = PF_INET,
1216 .obj_size = sizeof(struct tcp_request_sock),
1217 .rtx_syn_ack = tcp_rtx_synack,
1218 .send_ack = tcp_v4_reqsk_send_ack,
1219 .destructor = tcp_v4_reqsk_destructor,
1220 .send_reset = tcp_v4_send_reset,
1221 .syn_ack_timeout = tcp_syn_ack_timeout,
1222};
1223
1224static const struct tcp_request_sock_ops tcp_request_sock_ipv4_ops = {
1225 .mss_clamp = TCP_MSS_DEFAULT,
1226#ifdef CONFIG_TCP_MD5SIG
1227 .req_md5_lookup = tcp_v4_md5_lookup,
1228 .calc_md5_hash = tcp_v4_md5_hash_skb,
1229#endif
1230 .init_req = tcp_v4_init_req,
1231#ifdef CONFIG_SYN_COOKIES
1232 .cookie_init_seq = cookie_v4_init_sequence,
1233#endif
1234 .route_req = tcp_v4_route_req,
1235 .init_seq = tcp_v4_init_sequence,
1236 .send_synack = tcp_v4_send_synack,
1237};
1238
1239int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
1240{
1241 /* Never answer to SYNs send to broadcast or multicast */
1242 if (skb_rtable(skb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
1243 goto drop;
1244
1245 return tcp_conn_request(&tcp_request_sock_ops,
1246 &tcp_request_sock_ipv4_ops, sk, skb);
1247
1248drop:
1249 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
1250 return 0;
1251}
1252EXPORT_SYMBOL(tcp_v4_conn_request);
1253
1254
1255/*
1256 * The three way handshake has completed - we got a valid synack -
1257 * now create the new socket.
1258 */
1259struct sock *tcp_v4_syn_recv_sock(const struct sock *sk, struct sk_buff *skb,
1260 struct request_sock *req,
1261 struct dst_entry *dst,
1262 struct request_sock *req_unhash,
1263 bool *own_req)
1264{
1265 struct inet_request_sock *ireq;
1266 struct inet_sock *newinet;
1267 struct tcp_sock *newtp;
1268 struct sock *newsk;
1269#ifdef CONFIG_TCP_MD5SIG
1270 struct tcp_md5sig_key *key;
1271#endif
1272 struct ip_options_rcu *inet_opt;
1273
1274 if (sk_acceptq_is_full(sk))
1275 goto exit_overflow;
1276
1277 newsk = tcp_create_openreq_child(sk, req, skb);
1278 if (!newsk)
1279 goto exit_nonewsk;
1280
1281 newsk->sk_gso_type = SKB_GSO_TCPV4;
1282 inet_sk_rx_dst_set(newsk, skb);
1283
1284 newtp = tcp_sk(newsk);
1285 newinet = inet_sk(newsk);
1286 ireq = inet_rsk(req);
1287 sk_daddr_set(newsk, ireq->ir_rmt_addr);
1288 sk_rcv_saddr_set(newsk, ireq->ir_loc_addr);
1289 newsk->sk_bound_dev_if = ireq->ir_iif;
1290 newinet->inet_saddr = ireq->ir_loc_addr;
1291 inet_opt = ireq->opt;
1292 rcu_assign_pointer(newinet->inet_opt, inet_opt);
1293 ireq->opt = NULL;
1294 newinet->mc_index = inet_iif(skb);
1295 newinet->mc_ttl = ip_hdr(skb)->ttl;
1296 newinet->rcv_tos = ip_hdr(skb)->tos;
1297 inet_csk(newsk)->icsk_ext_hdr_len = 0;
1298 if (inet_opt)
1299 inet_csk(newsk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
1300 newinet->inet_id = newtp->write_seq ^ jiffies;
1301
1302 if (!dst) {
1303 dst = inet_csk_route_child_sock(sk, newsk, req);
1304 if (!dst)
1305 goto put_and_exit;
1306 } else {
1307 /* syncookie case : see end of cookie_v4_check() */
1308 }
1309 sk_setup_caps(newsk, dst);
1310
1311 tcp_ca_openreq_child(newsk, dst);
1312
1313 tcp_sync_mss(newsk, dst_mtu(dst));
1314 newtp->advmss = dst_metric_advmss(dst);
1315 if (tcp_sk(sk)->rx_opt.user_mss &&
1316 tcp_sk(sk)->rx_opt.user_mss < newtp->advmss)
1317 newtp->advmss = tcp_sk(sk)->rx_opt.user_mss;
1318
1319 tcp_initialize_rcv_mss(newsk);
1320
1321#ifdef CONFIG_TCP_MD5SIG
1322 /* Copy over the MD5 key from the original socket */
1323 key = tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&newinet->inet_daddr,
1324 AF_INET);
1325 if (key) {
1326 /*
1327 * We're using one, so create a matching key
1328 * on the newsk structure. If we fail to get
1329 * memory, then we end up not copying the key
1330 * across. Shucks.
1331 */
1332 tcp_md5_do_add(newsk, (union tcp_md5_addr *)&newinet->inet_daddr,
1333 AF_INET, key->key, key->keylen, GFP_ATOMIC);
1334 sk_nocaps_add(newsk, NETIF_F_GSO_MASK);
1335 }
1336#endif
1337
1338 if (__inet_inherit_port(sk, newsk) < 0)
1339 goto put_and_exit;
1340 *own_req = inet_ehash_nolisten(newsk, req_to_sk(req_unhash));
1341 if (*own_req)
1342 tcp_move_syn(newtp, req);
1343
1344 return newsk;
1345
1346exit_overflow:
1347 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
1348exit_nonewsk:
1349 dst_release(dst);
1350exit:
1351 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
1352 return NULL;
1353put_and_exit:
1354 inet_csk_prepare_forced_close(newsk);
1355 tcp_done(newsk);
1356 goto exit;
1357}
1358EXPORT_SYMBOL(tcp_v4_syn_recv_sock);
1359
1360static struct sock *tcp_v4_cookie_check(struct sock *sk, struct sk_buff *skb)
1361{
1362#ifdef CONFIG_SYN_COOKIES
1363 const struct tcphdr *th = tcp_hdr(skb);
1364
1365 if (!th->syn)
1366 sk = cookie_v4_check(sk, skb);
1367#endif
1368 return sk;
1369}
1370
1371/* The socket must have it's spinlock held when we get
1372 * here, unless it is a TCP_LISTEN socket.
1373 *
1374 * We have a potential double-lock case here, so even when
1375 * doing backlog processing we use the BH locking scheme.
1376 * This is because we cannot sleep with the original spinlock
1377 * held.
1378 */
1379int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
1380{
1381 struct sock *rsk;
1382
1383 if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
1384 struct dst_entry *dst = sk->sk_rx_dst;
1385
1386 sock_rps_save_rxhash(sk, skb);
1387 sk_mark_napi_id(sk, skb);
1388 if (dst) {
1389 if (inet_sk(sk)->rx_dst_ifindex != skb->skb_iif ||
1390 !dst->ops->check(dst, 0)) {
1391 dst_release(dst);
1392 sk->sk_rx_dst = NULL;
1393 }
1394 }
1395 tcp_rcv_established(sk, skb, tcp_hdr(skb), skb->len);
1396 return 0;
1397 }
1398
1399 if (tcp_checksum_complete(skb))
1400 goto csum_err;
1401
1402 if (sk->sk_state == TCP_LISTEN) {
1403 struct sock *nsk = tcp_v4_cookie_check(sk, skb);
1404
1405 if (!nsk)
1406 goto discard;
1407 if (nsk != sk) {
1408 sock_rps_save_rxhash(nsk, skb);
1409 sk_mark_napi_id(nsk, skb);
1410 if (tcp_child_process(sk, nsk, skb)) {
1411 rsk = nsk;
1412 goto reset;
1413 }
1414 return 0;
1415 }
1416 } else
1417 sock_rps_save_rxhash(sk, skb);
1418
1419 if (tcp_rcv_state_process(sk, skb)) {
1420 rsk = sk;
1421 goto reset;
1422 }
1423 return 0;
1424
1425reset:
1426 tcp_v4_send_reset(rsk, skb);
1427discard:
1428 kfree_skb(skb);
1429 /* Be careful here. If this function gets more complicated and
1430 * gcc suffers from register pressure on the x86, sk (in %ebx)
1431 * might be destroyed here. This current version compiles correctly,
1432 * but you have been warned.
1433 */
1434 return 0;
1435
1436csum_err:
1437 TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_CSUMERRORS);
1438 TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_INERRS);
1439 goto discard;
1440}
1441EXPORT_SYMBOL(tcp_v4_do_rcv);
1442
1443void tcp_v4_early_demux(struct sk_buff *skb)
1444{
1445 const struct iphdr *iph;
1446 const struct tcphdr *th;
1447 struct sock *sk;
1448
1449 if (skb->pkt_type != PACKET_HOST)
1450 return;
1451
1452 if (!pskb_may_pull(skb, skb_transport_offset(skb) + sizeof(struct tcphdr)))
1453 return;
1454
1455 iph = ip_hdr(skb);
1456 th = tcp_hdr(skb);
1457
1458 if (th->doff < sizeof(struct tcphdr) / 4)
1459 return;
1460
1461 sk = __inet_lookup_established(dev_net(skb->dev), &tcp_hashinfo,
1462 iph->saddr, th->source,
1463 iph->daddr, ntohs(th->dest),
1464 skb->skb_iif);
1465 if (sk) {
1466 skb->sk = sk;
1467 skb->destructor = sock_edemux;
1468 if (sk_fullsock(sk)) {
1469 struct dst_entry *dst = READ_ONCE(sk->sk_rx_dst);
1470
1471 if (dst)
1472 dst = dst_check(dst, 0);
1473 if (dst &&
1474 inet_sk(sk)->rx_dst_ifindex == skb->skb_iif)
1475 skb_dst_set_noref(skb, dst);
1476 }
1477 }
1478}
1479
1480/* Packet is added to VJ-style prequeue for processing in process
1481 * context, if a reader task is waiting. Apparently, this exciting
1482 * idea (VJ's mail "Re: query about TCP header on tcp-ip" of 07 Sep 93)
1483 * failed somewhere. Latency? Burstiness? Well, at least now we will
1484 * see, why it failed. 8)8) --ANK
1485 *
1486 */
1487bool tcp_prequeue(struct sock *sk, struct sk_buff *skb)
1488{
1489 struct tcp_sock *tp = tcp_sk(sk);
1490
1491 if (sysctl_tcp_low_latency || !tp->ucopy.task)
1492 return false;
1493
1494 if (skb->len <= tcp_hdrlen(skb) &&
1495 skb_queue_len(&tp->ucopy.prequeue) == 0)
1496 return false;
1497
1498 /* Before escaping RCU protected region, we need to take care of skb
1499 * dst. Prequeue is only enabled for established sockets.
1500 * For such sockets, we might need the skb dst only to set sk->sk_rx_dst
1501 * Instead of doing full sk_rx_dst validity here, let's perform
1502 * an optimistic check.
1503 */
1504 if (likely(sk->sk_rx_dst))
1505 skb_dst_drop(skb);
1506 else
1507 skb_dst_force_safe(skb);
1508
1509 __skb_queue_tail(&tp->ucopy.prequeue, skb);
1510 tp->ucopy.memory += skb->truesize;
1511 if (tp->ucopy.memory > sk->sk_rcvbuf) {
1512 struct sk_buff *skb1;
1513
1514 BUG_ON(sock_owned_by_user(sk));
1515
1516 while ((skb1 = __skb_dequeue(&tp->ucopy.prequeue)) != NULL) {
1517 sk_backlog_rcv(sk, skb1);
1518 NET_INC_STATS_BH(sock_net(sk),
1519 LINUX_MIB_TCPPREQUEUEDROPPED);
1520 }
1521
1522 tp->ucopy.memory = 0;
1523 } else if (skb_queue_len(&tp->ucopy.prequeue) == 1) {
1524 wake_up_interruptible_sync_poll(sk_sleep(sk),
1525 POLLIN | POLLRDNORM | POLLRDBAND);
1526 if (!inet_csk_ack_scheduled(sk))
1527 inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK,
1528 (3 * tcp_rto_min(sk)) / 4,
1529 TCP_RTO_MAX);
1530 }
1531 return true;
1532}
1533EXPORT_SYMBOL(tcp_prequeue);
1534
1535/*
1536 * From tcp_input.c
1537 */
1538
1539int tcp_v4_rcv(struct sk_buff *skb)
1540{
1541 const struct iphdr *iph;
1542 const struct tcphdr *th;
1543 struct sock *sk;
1544 int ret;
1545 struct net *net = dev_net(skb->dev);
1546
1547 if (skb->pkt_type != PACKET_HOST)
1548 goto discard_it;
1549
1550 /* Count it even if it's bad */
1551 TCP_INC_STATS_BH(net, TCP_MIB_INSEGS);
1552
1553 if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
1554 goto discard_it;
1555
1556 th = tcp_hdr(skb);
1557
1558 if (th->doff < sizeof(struct tcphdr) / 4)
1559 goto bad_packet;
1560 if (!pskb_may_pull(skb, th->doff * 4))
1561 goto discard_it;
1562
1563 /* An explanation is required here, I think.
1564 * Packet length and doff are validated by header prediction,
1565 * provided case of th->doff==0 is eliminated.
1566 * So, we defer the checks. */
1567
1568 if (skb_checksum_init(skb, IPPROTO_TCP, inet_compute_pseudo))
1569 goto csum_error;
1570
1571 th = tcp_hdr(skb);
1572 iph = ip_hdr(skb);
1573 /* This is tricky : We move IPCB at its correct location into TCP_SKB_CB()
1574 * barrier() makes sure compiler wont play fool^Waliasing games.
1575 */
1576 memmove(&TCP_SKB_CB(skb)->header.h4, IPCB(skb),
1577 sizeof(struct inet_skb_parm));
1578 barrier();
1579
1580 TCP_SKB_CB(skb)->seq = ntohl(th->seq);
1581 TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
1582 skb->len - th->doff * 4);
1583 TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
1584 TCP_SKB_CB(skb)->tcp_flags = tcp_flag_byte(th);
1585 TCP_SKB_CB(skb)->tcp_tw_isn = 0;
1586 TCP_SKB_CB(skb)->ip_dsfield = ipv4_get_dsfield(iph);
1587 TCP_SKB_CB(skb)->sacked = 0;
1588
1589lookup:
1590 sk = __inet_lookup_skb(&tcp_hashinfo, skb, __tcp_hdrlen(th), th->source,
1591 th->dest);
1592 if (!sk)
1593 goto no_tcp_socket;
1594
1595process:
1596 if (sk->sk_state == TCP_TIME_WAIT)
1597 goto do_time_wait;
1598
1599 if (sk->sk_state == TCP_NEW_SYN_RECV) {
1600 struct request_sock *req = inet_reqsk(sk);
1601 struct sock *nsk;
1602
1603 sk = req->rsk_listener;
1604 if (unlikely(tcp_v4_inbound_md5_hash(sk, skb))) {
1605 reqsk_put(req);
1606 goto discard_it;
1607 }
1608 if (unlikely(sk->sk_state != TCP_LISTEN)) {
1609 inet_csk_reqsk_queue_drop_and_put(sk, req);
1610 goto lookup;
1611 }
1612 sock_hold(sk);
1613 nsk = tcp_check_req(sk, skb, req, false);
1614 if (!nsk) {
1615 reqsk_put(req);
1616 goto discard_and_relse;
1617 }
1618 if (nsk == sk) {
1619 reqsk_put(req);
1620 } else if (tcp_child_process(sk, nsk, skb)) {
1621 tcp_v4_send_reset(nsk, skb);
1622 goto discard_and_relse;
1623 } else {
1624 sock_put(sk);
1625 return 0;
1626 }
1627 }
1628 if (unlikely(iph->ttl < inet_sk(sk)->min_ttl)) {
1629 NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP);
1630 goto discard_and_relse;
1631 }
1632
1633 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
1634 goto discard_and_relse;
1635
1636 if (tcp_v4_inbound_md5_hash(sk, skb))
1637 goto discard_and_relse;
1638
1639 nf_reset(skb);
1640
1641 if (sk_filter(sk, skb))
1642 goto discard_and_relse;
1643
1644 skb->dev = NULL;
1645
1646 if (sk->sk_state == TCP_LISTEN) {
1647 ret = tcp_v4_do_rcv(sk, skb);
1648 goto put_and_return;
1649 }
1650
1651 sk_incoming_cpu_update(sk);
1652
1653 bh_lock_sock_nested(sk);
1654 tcp_segs_in(tcp_sk(sk), skb);
1655 ret = 0;
1656 if (!sock_owned_by_user(sk)) {
1657 if (!tcp_prequeue(sk, skb))
1658 ret = tcp_v4_do_rcv(sk, skb);
1659 } else if (unlikely(sk_add_backlog(sk, skb,
1660 sk->sk_rcvbuf + sk->sk_sndbuf))) {
1661 bh_unlock_sock(sk);
1662 NET_INC_STATS_BH(net, LINUX_MIB_TCPBACKLOGDROP);
1663 goto discard_and_relse;
1664 }
1665 bh_unlock_sock(sk);
1666
1667put_and_return:
1668 sock_put(sk);
1669
1670 return ret;
1671
1672no_tcp_socket:
1673 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
1674 goto discard_it;
1675
1676 if (tcp_checksum_complete(skb)) {
1677csum_error:
1678 TCP_INC_STATS_BH(net, TCP_MIB_CSUMERRORS);
1679bad_packet:
1680 TCP_INC_STATS_BH(net, TCP_MIB_INERRS);
1681 } else {
1682 tcp_v4_send_reset(NULL, skb);
1683 }
1684
1685discard_it:
1686 /* Discard frame. */
1687 kfree_skb(skb);
1688 return 0;
1689
1690discard_and_relse:
1691 sock_put(sk);
1692 goto discard_it;
1693
1694do_time_wait:
1695 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
1696 inet_twsk_put(inet_twsk(sk));
1697 goto discard_it;
1698 }
1699
1700 if (tcp_checksum_complete(skb)) {
1701 inet_twsk_put(inet_twsk(sk));
1702 goto csum_error;
1703 }
1704 switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) {
1705 case TCP_TW_SYN: {
1706 struct sock *sk2 = inet_lookup_listener(dev_net(skb->dev),
1707 &tcp_hashinfo, skb,
1708 __tcp_hdrlen(th),
1709 iph->saddr, th->source,
1710 iph->daddr, th->dest,
1711 inet_iif(skb));
1712 if (sk2) {
1713 inet_twsk_deschedule_put(inet_twsk(sk));
1714 sk = sk2;
1715 goto process;
1716 }
1717 /* Fall through to ACK */
1718 }
1719 case TCP_TW_ACK:
1720 tcp_v4_timewait_ack(sk, skb);
1721 break;
1722 case TCP_TW_RST:
1723 tcp_v4_send_reset(sk, skb);
1724 inet_twsk_deschedule_put(inet_twsk(sk));
1725 goto discard_it;
1726 case TCP_TW_SUCCESS:;
1727 }
1728 goto discard_it;
1729}
1730
1731static struct timewait_sock_ops tcp_timewait_sock_ops = {
1732 .twsk_obj_size = sizeof(struct tcp_timewait_sock),
1733 .twsk_unique = tcp_twsk_unique,
1734 .twsk_destructor= tcp_twsk_destructor,
1735};
1736
1737void inet_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb)
1738{
1739 struct dst_entry *dst = skb_dst(skb);
1740
1741 if (dst && dst_hold_safe(dst)) {
1742 sk->sk_rx_dst = dst;
1743 inet_sk(sk)->rx_dst_ifindex = skb->skb_iif;
1744 }
1745}
1746EXPORT_SYMBOL(inet_sk_rx_dst_set);
1747
1748const struct inet_connection_sock_af_ops ipv4_specific = {
1749 .queue_xmit = ip_queue_xmit,
1750 .send_check = tcp_v4_send_check,
1751 .rebuild_header = inet_sk_rebuild_header,
1752 .sk_rx_dst_set = inet_sk_rx_dst_set,
1753 .conn_request = tcp_v4_conn_request,
1754 .syn_recv_sock = tcp_v4_syn_recv_sock,
1755 .net_header_len = sizeof(struct iphdr),
1756 .setsockopt = ip_setsockopt,
1757 .getsockopt = ip_getsockopt,
1758 .addr2sockaddr = inet_csk_addr2sockaddr,
1759 .sockaddr_len = sizeof(struct sockaddr_in),
1760 .bind_conflict = inet_csk_bind_conflict,
1761#ifdef CONFIG_COMPAT
1762 .compat_setsockopt = compat_ip_setsockopt,
1763 .compat_getsockopt = compat_ip_getsockopt,
1764#endif
1765 .mtu_reduced = tcp_v4_mtu_reduced,
1766};
1767EXPORT_SYMBOL(ipv4_specific);
1768
1769#ifdef CONFIG_TCP_MD5SIG
1770static const struct tcp_sock_af_ops tcp_sock_ipv4_specific = {
1771 .md5_lookup = tcp_v4_md5_lookup,
1772 .calc_md5_hash = tcp_v4_md5_hash_skb,
1773 .md5_parse = tcp_v4_parse_md5_keys,
1774};
1775#endif
1776
1777/* NOTE: A lot of things set to zero explicitly by call to
1778 * sk_alloc() so need not be done here.
1779 */
1780static int tcp_v4_init_sock(struct sock *sk)
1781{
1782 struct inet_connection_sock *icsk = inet_csk(sk);
1783
1784 tcp_init_sock(sk);
1785
1786 icsk->icsk_af_ops = &ipv4_specific;
1787
1788#ifdef CONFIG_TCP_MD5SIG
1789 tcp_sk(sk)->af_specific = &tcp_sock_ipv4_specific;
1790#endif
1791
1792 return 0;
1793}
1794
1795void tcp_v4_destroy_sock(struct sock *sk)
1796{
1797 struct tcp_sock *tp = tcp_sk(sk);
1798
1799 tcp_clear_xmit_timers(sk);
1800
1801 tcp_cleanup_congestion_control(sk);
1802
1803 /* Cleanup up the write buffer. */
1804 tcp_write_queue_purge(sk);
1805
1806 /* Cleans up our, hopefully empty, out_of_order_queue. */
1807 __skb_queue_purge(&tp->out_of_order_queue);
1808
1809#ifdef CONFIG_TCP_MD5SIG
1810 /* Clean up the MD5 key list, if any */
1811 if (tp->md5sig_info) {
1812 tcp_clear_md5_list(sk);
1813 kfree_rcu(tp->md5sig_info, rcu);
1814 tp->md5sig_info = NULL;
1815 }
1816#endif
1817
1818 /* Clean prequeue, it must be empty really */
1819 __skb_queue_purge(&tp->ucopy.prequeue);
1820
1821 /* Clean up a referenced TCP bind bucket. */
1822 if (inet_csk(sk)->icsk_bind_hash)
1823 inet_put_port(sk);
1824
1825 BUG_ON(tp->fastopen_rsk);
1826
1827 /* If socket is aborted during connect operation */
1828 tcp_free_fastopen_req(tp);
1829 tcp_saved_syn_free(tp);
1830
1831 sk_sockets_allocated_dec(sk);
1832
1833 if (mem_cgroup_sockets_enabled && sk->sk_memcg)
1834 sock_release_memcg(sk);
1835}
1836EXPORT_SYMBOL(tcp_v4_destroy_sock);
1837
1838#ifdef CONFIG_PROC_FS
1839/* Proc filesystem TCP sock list dumping. */
1840
1841/*
1842 * Get next listener socket follow cur. If cur is NULL, get first socket
1843 * starting from bucket given in st->bucket; when st->bucket is zero the
1844 * very first socket in the hash table is returned.
1845 */
1846static void *listening_get_next(struct seq_file *seq, void *cur)
1847{
1848 struct inet_connection_sock *icsk;
1849 struct hlist_nulls_node *node;
1850 struct sock *sk = cur;
1851 struct inet_listen_hashbucket *ilb;
1852 struct tcp_iter_state *st = seq->private;
1853 struct net *net = seq_file_net(seq);
1854
1855 if (!sk) {
1856 ilb = &tcp_hashinfo.listening_hash[st->bucket];
1857 spin_lock_bh(&ilb->lock);
1858 sk = sk_nulls_head(&ilb->head);
1859 st->offset = 0;
1860 goto get_sk;
1861 }
1862 ilb = &tcp_hashinfo.listening_hash[st->bucket];
1863 ++st->num;
1864 ++st->offset;
1865
1866 sk = sk_nulls_next(sk);
1867get_sk:
1868 sk_nulls_for_each_from(sk, node) {
1869 if (!net_eq(sock_net(sk), net))
1870 continue;
1871 if (sk->sk_family == st->family) {
1872 cur = sk;
1873 goto out;
1874 }
1875 icsk = inet_csk(sk);
1876 }
1877 spin_unlock_bh(&ilb->lock);
1878 st->offset = 0;
1879 if (++st->bucket < INET_LHTABLE_SIZE) {
1880 ilb = &tcp_hashinfo.listening_hash[st->bucket];
1881 spin_lock_bh(&ilb->lock);
1882 sk = sk_nulls_head(&ilb->head);
1883 goto get_sk;
1884 }
1885 cur = NULL;
1886out:
1887 return cur;
1888}
1889
1890static void *listening_get_idx(struct seq_file *seq, loff_t *pos)
1891{
1892 struct tcp_iter_state *st = seq->private;
1893 void *rc;
1894
1895 st->bucket = 0;
1896 st->offset = 0;
1897 rc = listening_get_next(seq, NULL);
1898
1899 while (rc && *pos) {
1900 rc = listening_get_next(seq, rc);
1901 --*pos;
1902 }
1903 return rc;
1904}
1905
1906static inline bool empty_bucket(const struct tcp_iter_state *st)
1907{
1908 return hlist_nulls_empty(&tcp_hashinfo.ehash[st->bucket].chain);
1909}
1910
1911/*
1912 * Get first established socket starting from bucket given in st->bucket.
1913 * If st->bucket is zero, the very first socket in the hash is returned.
1914 */
1915static void *established_get_first(struct seq_file *seq)
1916{
1917 struct tcp_iter_state *st = seq->private;
1918 struct net *net = seq_file_net(seq);
1919 void *rc = NULL;
1920
1921 st->offset = 0;
1922 for (; st->bucket <= tcp_hashinfo.ehash_mask; ++st->bucket) {
1923 struct sock *sk;
1924 struct hlist_nulls_node *node;
1925 spinlock_t *lock = inet_ehash_lockp(&tcp_hashinfo, st->bucket);
1926
1927 /* Lockless fast path for the common case of empty buckets */
1928 if (empty_bucket(st))
1929 continue;
1930
1931 spin_lock_bh(lock);
1932 sk_nulls_for_each(sk, node, &tcp_hashinfo.ehash[st->bucket].chain) {
1933 if (sk->sk_family != st->family ||
1934 !net_eq(sock_net(sk), net)) {
1935 continue;
1936 }
1937 rc = sk;
1938 goto out;
1939 }
1940 spin_unlock_bh(lock);
1941 }
1942out:
1943 return rc;
1944}
1945
1946static void *established_get_next(struct seq_file *seq, void *cur)
1947{
1948 struct sock *sk = cur;
1949 struct hlist_nulls_node *node;
1950 struct tcp_iter_state *st = seq->private;
1951 struct net *net = seq_file_net(seq);
1952
1953 ++st->num;
1954 ++st->offset;
1955
1956 sk = sk_nulls_next(sk);
1957
1958 sk_nulls_for_each_from(sk, node) {
1959 if (sk->sk_family == st->family && net_eq(sock_net(sk), net))
1960 return sk;
1961 }
1962
1963 spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
1964 ++st->bucket;
1965 return established_get_first(seq);
1966}
1967
1968static void *established_get_idx(struct seq_file *seq, loff_t pos)
1969{
1970 struct tcp_iter_state *st = seq->private;
1971 void *rc;
1972
1973 st->bucket = 0;
1974 rc = established_get_first(seq);
1975
1976 while (rc && pos) {
1977 rc = established_get_next(seq, rc);
1978 --pos;
1979 }
1980 return rc;
1981}
1982
1983static void *tcp_get_idx(struct seq_file *seq, loff_t pos)
1984{
1985 void *rc;
1986 struct tcp_iter_state *st = seq->private;
1987
1988 st->state = TCP_SEQ_STATE_LISTENING;
1989 rc = listening_get_idx(seq, &pos);
1990
1991 if (!rc) {
1992 st->state = TCP_SEQ_STATE_ESTABLISHED;
1993 rc = established_get_idx(seq, pos);
1994 }
1995
1996 return rc;
1997}
1998
1999static void *tcp_seek_last_pos(struct seq_file *seq)
2000{
2001 struct tcp_iter_state *st = seq->private;
2002 int offset = st->offset;
2003 int orig_num = st->num;
2004 void *rc = NULL;
2005
2006 switch (st->state) {
2007 case TCP_SEQ_STATE_LISTENING:
2008 if (st->bucket >= INET_LHTABLE_SIZE)
2009 break;
2010 st->state = TCP_SEQ_STATE_LISTENING;
2011 rc = listening_get_next(seq, NULL);
2012 while (offset-- && rc)
2013 rc = listening_get_next(seq, rc);
2014 if (rc)
2015 break;
2016 st->bucket = 0;
2017 st->state = TCP_SEQ_STATE_ESTABLISHED;
2018 /* Fallthrough */
2019 case TCP_SEQ_STATE_ESTABLISHED:
2020 if (st->bucket > tcp_hashinfo.ehash_mask)
2021 break;
2022 rc = established_get_first(seq);
2023 while (offset-- && rc)
2024 rc = established_get_next(seq, rc);
2025 }
2026
2027 st->num = orig_num;
2028
2029 return rc;
2030}
2031
2032static void *tcp_seq_start(struct seq_file *seq, loff_t *pos)
2033{
2034 struct tcp_iter_state *st = seq->private;
2035 void *rc;
2036
2037 if (*pos && *pos == st->last_pos) {
2038 rc = tcp_seek_last_pos(seq);
2039 if (rc)
2040 goto out;
2041 }
2042
2043 st->state = TCP_SEQ_STATE_LISTENING;
2044 st->num = 0;
2045 st->bucket = 0;
2046 st->offset = 0;
2047 rc = *pos ? tcp_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
2048
2049out:
2050 st->last_pos = *pos;
2051 return rc;
2052}
2053
2054static void *tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2055{
2056 struct tcp_iter_state *st = seq->private;
2057 void *rc = NULL;
2058
2059 if (v == SEQ_START_TOKEN) {
2060 rc = tcp_get_idx(seq, 0);
2061 goto out;
2062 }
2063
2064 switch (st->state) {
2065 case TCP_SEQ_STATE_LISTENING:
2066 rc = listening_get_next(seq, v);
2067 if (!rc) {
2068 st->state = TCP_SEQ_STATE_ESTABLISHED;
2069 st->bucket = 0;
2070 st->offset = 0;
2071 rc = established_get_first(seq);
2072 }
2073 break;
2074 case TCP_SEQ_STATE_ESTABLISHED:
2075 rc = established_get_next(seq, v);
2076 break;
2077 }
2078out:
2079 ++*pos;
2080 st->last_pos = *pos;
2081 return rc;
2082}
2083
2084static void tcp_seq_stop(struct seq_file *seq, void *v)
2085{
2086 struct tcp_iter_state *st = seq->private;
2087
2088 switch (st->state) {
2089 case TCP_SEQ_STATE_LISTENING:
2090 if (v != SEQ_START_TOKEN)
2091 spin_unlock_bh(&tcp_hashinfo.listening_hash[st->bucket].lock);
2092 break;
2093 case TCP_SEQ_STATE_ESTABLISHED:
2094 if (v)
2095 spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
2096 break;
2097 }
2098}
2099
2100int tcp_seq_open(struct inode *inode, struct file *file)
2101{
2102 struct tcp_seq_afinfo *afinfo = PDE_DATA(inode);
2103 struct tcp_iter_state *s;
2104 int err;
2105
2106 err = seq_open_net(inode, file, &afinfo->seq_ops,
2107 sizeof(struct tcp_iter_state));
2108 if (err < 0)
2109 return err;
2110
2111 s = ((struct seq_file *)file->private_data)->private;
2112 s->family = afinfo->family;
2113 s->last_pos = 0;
2114 return 0;
2115}
2116EXPORT_SYMBOL(tcp_seq_open);
2117
2118int tcp_proc_register(struct net *net, struct tcp_seq_afinfo *afinfo)
2119{
2120 int rc = 0;
2121 struct proc_dir_entry *p;
2122
2123 afinfo->seq_ops.start = tcp_seq_start;
2124 afinfo->seq_ops.next = tcp_seq_next;
2125 afinfo->seq_ops.stop = tcp_seq_stop;
2126
2127 p = proc_create_data(afinfo->name, S_IRUGO, net->proc_net,
2128 afinfo->seq_fops, afinfo);
2129 if (!p)
2130 rc = -ENOMEM;
2131 return rc;
2132}
2133EXPORT_SYMBOL(tcp_proc_register);
2134
2135void tcp_proc_unregister(struct net *net, struct tcp_seq_afinfo *afinfo)
2136{
2137 remove_proc_entry(afinfo->name, net->proc_net);
2138}
2139EXPORT_SYMBOL(tcp_proc_unregister);
2140
2141static void get_openreq4(const struct request_sock *req,
2142 struct seq_file *f, int i)
2143{
2144 const struct inet_request_sock *ireq = inet_rsk(req);
2145 long delta = req->rsk_timer.expires - jiffies;
2146
2147 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2148 " %02X %08X:%08X %02X:%08lX %08X %5u %8d %u %d %pK",
2149 i,
2150 ireq->ir_loc_addr,
2151 ireq->ir_num,
2152 ireq->ir_rmt_addr,
2153 ntohs(ireq->ir_rmt_port),
2154 TCP_SYN_RECV,
2155 0, 0, /* could print option size, but that is af dependent. */
2156 1, /* timers active (only the expire timer) */
2157 jiffies_delta_to_clock_t(delta),
2158 req->num_timeout,
2159 from_kuid_munged(seq_user_ns(f),
2160 sock_i_uid(req->rsk_listener)),
2161 0, /* non standard timer */
2162 0, /* open_requests have no inode */
2163 0,
2164 req);
2165}
2166
2167static void get_tcp4_sock(struct sock *sk, struct seq_file *f, int i)
2168{
2169 int timer_active;
2170 unsigned long timer_expires;
2171 const struct tcp_sock *tp = tcp_sk(sk);
2172 const struct inet_connection_sock *icsk = inet_csk(sk);
2173 const struct inet_sock *inet = inet_sk(sk);
2174 const struct fastopen_queue *fastopenq = &icsk->icsk_accept_queue.fastopenq;
2175 __be32 dest = inet->inet_daddr;
2176 __be32 src = inet->inet_rcv_saddr;
2177 __u16 destp = ntohs(inet->inet_dport);
2178 __u16 srcp = ntohs(inet->inet_sport);
2179 int rx_queue;
2180 int state;
2181
2182 if (icsk->icsk_pending == ICSK_TIME_RETRANS ||
2183 icsk->icsk_pending == ICSK_TIME_EARLY_RETRANS ||
2184 icsk->icsk_pending == ICSK_TIME_LOSS_PROBE) {
2185 timer_active = 1;
2186 timer_expires = icsk->icsk_timeout;
2187 } else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
2188 timer_active = 4;
2189 timer_expires = icsk->icsk_timeout;
2190 } else if (timer_pending(&sk->sk_timer)) {
2191 timer_active = 2;
2192 timer_expires = sk->sk_timer.expires;
2193 } else {
2194 timer_active = 0;
2195 timer_expires = jiffies;
2196 }
2197
2198 state = sk_state_load(sk);
2199 if (state == TCP_LISTEN)
2200 rx_queue = sk->sk_ack_backlog;
2201 else
2202 /* Because we don't lock the socket,
2203 * we might find a transient negative value.
2204 */
2205 rx_queue = max_t(int, tp->rcv_nxt - tp->copied_seq, 0);
2206
2207 seq_printf(f, "%4d: %08X:%04X %08X:%04X %02X %08X:%08X %02X:%08lX "
2208 "%08X %5u %8d %lu %d %pK %lu %lu %u %u %d",
2209 i, src, srcp, dest, destp, state,
2210 tp->write_seq - tp->snd_una,
2211 rx_queue,
2212 timer_active,
2213 jiffies_delta_to_clock_t(timer_expires - jiffies),
2214 icsk->icsk_retransmits,
2215 from_kuid_munged(seq_user_ns(f), sock_i_uid(sk)),
2216 icsk->icsk_probes_out,
2217 sock_i_ino(sk),
2218 atomic_read(&sk->sk_refcnt), sk,
2219 jiffies_to_clock_t(icsk->icsk_rto),
2220 jiffies_to_clock_t(icsk->icsk_ack.ato),
2221 (icsk->icsk_ack.quick << 1) | icsk->icsk_ack.pingpong,
2222 tp->snd_cwnd,
2223 state == TCP_LISTEN ?
2224 fastopenq->max_qlen :
2225 (tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh));
2226}
2227
2228static void get_timewait4_sock(const struct inet_timewait_sock *tw,
2229 struct seq_file *f, int i)
2230{
2231 long delta = tw->tw_timer.expires - jiffies;
2232 __be32 dest, src;
2233 __u16 destp, srcp;
2234
2235 dest = tw->tw_daddr;
2236 src = tw->tw_rcv_saddr;
2237 destp = ntohs(tw->tw_dport);
2238 srcp = ntohs(tw->tw_sport);
2239
2240 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2241 " %02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK",
2242 i, src, srcp, dest, destp, tw->tw_substate, 0, 0,
2243 3, jiffies_delta_to_clock_t(delta), 0, 0, 0, 0,
2244 atomic_read(&tw->tw_refcnt), tw);
2245}
2246
2247#define TMPSZ 150
2248
2249static int tcp4_seq_show(struct seq_file *seq, void *v)
2250{
2251 struct tcp_iter_state *st;
2252 struct sock *sk = v;
2253
2254 seq_setwidth(seq, TMPSZ - 1);
2255 if (v == SEQ_START_TOKEN) {
2256 seq_puts(seq, " sl local_address rem_address st tx_queue "
2257 "rx_queue tr tm->when retrnsmt uid timeout "
2258 "inode");
2259 goto out;
2260 }
2261 st = seq->private;
2262
2263 if (sk->sk_state == TCP_TIME_WAIT)
2264 get_timewait4_sock(v, seq, st->num);
2265 else if (sk->sk_state == TCP_NEW_SYN_RECV)
2266 get_openreq4(v, seq, st->num);
2267 else
2268 get_tcp4_sock(v, seq, st->num);
2269out:
2270 seq_pad(seq, '\n');
2271 return 0;
2272}
2273
2274static const struct file_operations tcp_afinfo_seq_fops = {
2275 .owner = THIS_MODULE,
2276 .open = tcp_seq_open,
2277 .read = seq_read,
2278 .llseek = seq_lseek,
2279 .release = seq_release_net
2280};
2281
2282static struct tcp_seq_afinfo tcp4_seq_afinfo = {
2283 .name = "tcp",
2284 .family = AF_INET,
2285 .seq_fops = &tcp_afinfo_seq_fops,
2286 .seq_ops = {
2287 .show = tcp4_seq_show,
2288 },
2289};
2290
2291static int __net_init tcp4_proc_init_net(struct net *net)
2292{
2293 return tcp_proc_register(net, &tcp4_seq_afinfo);
2294}
2295
2296static void __net_exit tcp4_proc_exit_net(struct net *net)
2297{
2298 tcp_proc_unregister(net, &tcp4_seq_afinfo);
2299}
2300
2301static struct pernet_operations tcp4_net_ops = {
2302 .init = tcp4_proc_init_net,
2303 .exit = tcp4_proc_exit_net,
2304};
2305
2306int __init tcp4_proc_init(void)
2307{
2308 return register_pernet_subsys(&tcp4_net_ops);
2309}
2310
2311void tcp4_proc_exit(void)
2312{
2313 unregister_pernet_subsys(&tcp4_net_ops);
2314}
2315#endif /* CONFIG_PROC_FS */
2316
2317struct proto tcp_prot = {
2318 .name = "TCP",
2319 .owner = THIS_MODULE,
2320 .close = tcp_close,
2321 .connect = tcp_v4_connect,
2322 .disconnect = tcp_disconnect,
2323 .accept = inet_csk_accept,
2324 .ioctl = tcp_ioctl,
2325 .init = tcp_v4_init_sock,
2326 .destroy = tcp_v4_destroy_sock,
2327 .shutdown = tcp_shutdown,
2328 .setsockopt = tcp_setsockopt,
2329 .getsockopt = tcp_getsockopt,
2330 .recvmsg = tcp_recvmsg,
2331 .sendmsg = tcp_sendmsg,
2332 .sendpage = tcp_sendpage,
2333 .backlog_rcv = tcp_v4_do_rcv,
2334 .release_cb = tcp_release_cb,
2335 .hash = inet_hash,
2336 .unhash = inet_unhash,
2337 .get_port = inet_csk_get_port,
2338 .enter_memory_pressure = tcp_enter_memory_pressure,
2339 .stream_memory_free = tcp_stream_memory_free,
2340 .sockets_allocated = &tcp_sockets_allocated,
2341 .orphan_count = &tcp_orphan_count,
2342 .memory_allocated = &tcp_memory_allocated,
2343 .memory_pressure = &tcp_memory_pressure,
2344 .sysctl_mem = sysctl_tcp_mem,
2345 .sysctl_wmem = sysctl_tcp_wmem,
2346 .sysctl_rmem = sysctl_tcp_rmem,
2347 .max_header = MAX_TCP_HEADER,
2348 .obj_size = sizeof(struct tcp_sock),
2349 .slab_flags = SLAB_DESTROY_BY_RCU,
2350 .twsk_prot = &tcp_timewait_sock_ops,
2351 .rsk_prot = &tcp_request_sock_ops,
2352 .h.hashinfo = &tcp_hashinfo,
2353 .no_autobind = true,
2354#ifdef CONFIG_COMPAT
2355 .compat_setsockopt = compat_tcp_setsockopt,
2356 .compat_getsockopt = compat_tcp_getsockopt,
2357#endif
2358 .diag_destroy = tcp_abort,
2359};
2360EXPORT_SYMBOL(tcp_prot);
2361
2362static void __net_exit tcp_sk_exit(struct net *net)
2363{
2364 int cpu;
2365
2366 for_each_possible_cpu(cpu)
2367 inet_ctl_sock_destroy(*per_cpu_ptr(net->ipv4.tcp_sk, cpu));
2368 free_percpu(net->ipv4.tcp_sk);
2369}
2370
2371static int __net_init tcp_sk_init(struct net *net)
2372{
2373 int res, cpu;
2374
2375 net->ipv4.tcp_sk = alloc_percpu(struct sock *);
2376 if (!net->ipv4.tcp_sk)
2377 return -ENOMEM;
2378
2379 for_each_possible_cpu(cpu) {
2380 struct sock *sk;
2381
2382 res = inet_ctl_sock_create(&sk, PF_INET, SOCK_RAW,
2383 IPPROTO_TCP, net);
2384 if (res)
2385 goto fail;
2386 *per_cpu_ptr(net->ipv4.tcp_sk, cpu) = sk;
2387 }
2388
2389 net->ipv4.sysctl_tcp_ecn = 2;
2390 net->ipv4.sysctl_tcp_ecn_fallback = 1;
2391
2392 net->ipv4.sysctl_tcp_base_mss = TCP_BASE_MSS;
2393 net->ipv4.sysctl_tcp_probe_threshold = TCP_PROBE_THRESHOLD;
2394 net->ipv4.sysctl_tcp_probe_interval = TCP_PROBE_INTERVAL;
2395
2396 net->ipv4.sysctl_tcp_keepalive_time = TCP_KEEPALIVE_TIME;
2397 net->ipv4.sysctl_tcp_keepalive_probes = TCP_KEEPALIVE_PROBES;
2398 net->ipv4.sysctl_tcp_keepalive_intvl = TCP_KEEPALIVE_INTVL;
2399
2400 net->ipv4.sysctl_tcp_syn_retries = TCP_SYN_RETRIES;
2401 net->ipv4.sysctl_tcp_synack_retries = TCP_SYNACK_RETRIES;
2402 net->ipv4.sysctl_tcp_syncookies = 1;
2403 net->ipv4.sysctl_tcp_reordering = TCP_FASTRETRANS_THRESH;
2404 net->ipv4.sysctl_tcp_retries1 = TCP_RETR1;
2405 net->ipv4.sysctl_tcp_retries2 = TCP_RETR2;
2406 net->ipv4.sysctl_tcp_orphan_retries = 0;
2407 net->ipv4.sysctl_tcp_fin_timeout = TCP_FIN_TIMEOUT;
2408 net->ipv4.sysctl_tcp_notsent_lowat = UINT_MAX;
2409
2410 return 0;
2411fail:
2412 tcp_sk_exit(net);
2413
2414 return res;
2415}
2416
2417static void __net_exit tcp_sk_exit_batch(struct list_head *net_exit_list)
2418{
2419 inet_twsk_purge(&tcp_hashinfo, &tcp_death_row, AF_INET);
2420}
2421
2422static struct pernet_operations __net_initdata tcp_sk_ops = {
2423 .init = tcp_sk_init,
2424 .exit = tcp_sk_exit,
2425 .exit_batch = tcp_sk_exit_batch,
2426};
2427
2428void __init tcp_v4_init(void)
2429{
2430 inet_hashinfo_init(&tcp_hashinfo);
2431 if (register_pernet_subsys(&tcp_sk_ops))
2432 panic("Failed to create the TCP control socket.\n");
2433}