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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/netdma.h>
76#include <net/secure_seq.h>
77#include <net/tcp_memcontrol.h>
78
79#include <linux/inet.h>
80#include <linux/ipv6.h>
81#include <linux/stddef.h>
82#include <linux/proc_fs.h>
83#include <linux/seq_file.h>
84
85#include <linux/crypto.h>
86#include <linux/scatterlist.h>
87
88int sysctl_tcp_tw_reuse __read_mostly;
89int sysctl_tcp_low_latency __read_mostly;
90EXPORT_SYMBOL(sysctl_tcp_low_latency);
91
92
93#ifdef CONFIG_TCP_MD5SIG
94static int tcp_v4_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key,
95 __be32 daddr, __be32 saddr, const struct tcphdr *th);
96#endif
97
98struct inet_hashinfo tcp_hashinfo;
99EXPORT_SYMBOL(tcp_hashinfo);
100
101static inline __u32 tcp_v4_init_sequence(const struct sk_buff *skb)
102{
103 return secure_tcp_sequence_number(ip_hdr(skb)->daddr,
104 ip_hdr(skb)->saddr,
105 tcp_hdr(skb)->dest,
106 tcp_hdr(skb)->source);
107}
108
109int tcp_twsk_unique(struct sock *sk, struct sock *sktw, void *twp)
110{
111 const struct tcp_timewait_sock *tcptw = tcp_twsk(sktw);
112 struct tcp_sock *tp = tcp_sk(sk);
113
114 /* With PAWS, it is safe from the viewpoint
115 of data integrity. Even without PAWS it is safe provided sequence
116 spaces do not overlap i.e. at data rates <= 80Mbit/sec.
117
118 Actually, the idea is close to VJ's one, only timestamp cache is
119 held not per host, but per port pair and TW bucket is used as state
120 holder.
121
122 If TW bucket has been already destroyed we fall back to VJ's scheme
123 and use initial timestamp retrieved from peer table.
124 */
125 if (tcptw->tw_ts_recent_stamp &&
126 (twp == NULL || (sysctl_tcp_tw_reuse &&
127 get_seconds() - tcptw->tw_ts_recent_stamp > 1))) {
128 tp->write_seq = tcptw->tw_snd_nxt + 65535 + 2;
129 if (tp->write_seq == 0)
130 tp->write_seq = 1;
131 tp->rx_opt.ts_recent = tcptw->tw_ts_recent;
132 tp->rx_opt.ts_recent_stamp = tcptw->tw_ts_recent_stamp;
133 sock_hold(sktw);
134 return 1;
135 }
136
137 return 0;
138}
139EXPORT_SYMBOL_GPL(tcp_twsk_unique);
140
141static int tcp_repair_connect(struct sock *sk)
142{
143 tcp_connect_init(sk);
144 tcp_finish_connect(sk, NULL);
145
146 return 0;
147}
148
149/* This will initiate an outgoing connection. */
150int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
151{
152 struct sockaddr_in *usin = (struct sockaddr_in *)uaddr;
153 struct inet_sock *inet = inet_sk(sk);
154 struct tcp_sock *tp = tcp_sk(sk);
155 __be16 orig_sport, orig_dport;
156 __be32 daddr, nexthop;
157 struct flowi4 *fl4;
158 struct rtable *rt;
159 int err;
160 struct ip_options_rcu *inet_opt;
161
162 if (addr_len < sizeof(struct sockaddr_in))
163 return -EINVAL;
164
165 if (usin->sin_family != AF_INET)
166 return -EAFNOSUPPORT;
167
168 nexthop = daddr = usin->sin_addr.s_addr;
169 inet_opt = rcu_dereference_protected(inet->inet_opt,
170 sock_owned_by_user(sk));
171 if (inet_opt && inet_opt->opt.srr) {
172 if (!daddr)
173 return -EINVAL;
174 nexthop = inet_opt->opt.faddr;
175 }
176
177 orig_sport = inet->inet_sport;
178 orig_dport = usin->sin_port;
179 fl4 = &inet->cork.fl.u.ip4;
180 rt = ip_route_connect(fl4, nexthop, inet->inet_saddr,
181 RT_CONN_FLAGS(sk), sk->sk_bound_dev_if,
182 IPPROTO_TCP,
183 orig_sport, orig_dport, sk, true);
184 if (IS_ERR(rt)) {
185 err = PTR_ERR(rt);
186 if (err == -ENETUNREACH)
187 IP_INC_STATS_BH(sock_net(sk), IPSTATS_MIB_OUTNOROUTES);
188 return err;
189 }
190
191 if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) {
192 ip_rt_put(rt);
193 return -ENETUNREACH;
194 }
195
196 if (!inet_opt || !inet_opt->opt.srr)
197 daddr = fl4->daddr;
198
199 if (!inet->inet_saddr)
200 inet->inet_saddr = fl4->saddr;
201 inet->inet_rcv_saddr = inet->inet_saddr;
202
203 if (tp->rx_opt.ts_recent_stamp && inet->inet_daddr != daddr) {
204 /* Reset inherited state */
205 tp->rx_opt.ts_recent = 0;
206 tp->rx_opt.ts_recent_stamp = 0;
207 if (likely(!tp->repair))
208 tp->write_seq = 0;
209 }
210
211 if (tcp_death_row.sysctl_tw_recycle &&
212 !tp->rx_opt.ts_recent_stamp && fl4->daddr == daddr) {
213 struct inet_peer *peer = rt_get_peer(rt, fl4->daddr);
214 /*
215 * VJ's idea. We save last timestamp seen from
216 * the destination in peer table, when entering state
217 * TIME-WAIT * and initialize rx_opt.ts_recent from it,
218 * when trying new connection.
219 */
220 if (peer) {
221 inet_peer_refcheck(peer);
222 if ((u32)get_seconds() - peer->tcp_ts_stamp <= TCP_PAWS_MSL) {
223 tp->rx_opt.ts_recent_stamp = peer->tcp_ts_stamp;
224 tp->rx_opt.ts_recent = peer->tcp_ts;
225 }
226 }
227 }
228
229 inet->inet_dport = usin->sin_port;
230 inet->inet_daddr = daddr;
231
232 inet_csk(sk)->icsk_ext_hdr_len = 0;
233 if (inet_opt)
234 inet_csk(sk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
235
236 tp->rx_opt.mss_clamp = TCP_MSS_DEFAULT;
237
238 /* Socket identity is still unknown (sport may be zero).
239 * However we set state to SYN-SENT and not releasing socket
240 * lock select source port, enter ourselves into the hash tables and
241 * complete initialization after this.
242 */
243 tcp_set_state(sk, TCP_SYN_SENT);
244 err = inet_hash_connect(&tcp_death_row, sk);
245 if (err)
246 goto failure;
247
248 rt = ip_route_newports(fl4, rt, orig_sport, orig_dport,
249 inet->inet_sport, inet->inet_dport, sk);
250 if (IS_ERR(rt)) {
251 err = PTR_ERR(rt);
252 rt = NULL;
253 goto failure;
254 }
255 /* OK, now commit destination to socket. */
256 sk->sk_gso_type = SKB_GSO_TCPV4;
257 sk_setup_caps(sk, &rt->dst);
258
259 if (!tp->write_seq && likely(!tp->repair))
260 tp->write_seq = secure_tcp_sequence_number(inet->inet_saddr,
261 inet->inet_daddr,
262 inet->inet_sport,
263 usin->sin_port);
264
265 inet->inet_id = tp->write_seq ^ jiffies;
266
267 if (likely(!tp->repair))
268 err = tcp_connect(sk);
269 else
270 err = tcp_repair_connect(sk);
271
272 rt = NULL;
273 if (err)
274 goto failure;
275
276 return 0;
277
278failure:
279 /*
280 * This unhashes the socket and releases the local port,
281 * if necessary.
282 */
283 tcp_set_state(sk, TCP_CLOSE);
284 ip_rt_put(rt);
285 sk->sk_route_caps = 0;
286 inet->inet_dport = 0;
287 return err;
288}
289EXPORT_SYMBOL(tcp_v4_connect);
290
291/*
292 * This routine does path mtu discovery as defined in RFC1191.
293 */
294static void do_pmtu_discovery(struct sock *sk, const struct iphdr *iph, u32 mtu)
295{
296 struct dst_entry *dst;
297 struct inet_sock *inet = inet_sk(sk);
298
299 /* We are not interested in TCP_LISTEN and open_requests (SYN-ACKs
300 * send out by Linux are always <576bytes so they should go through
301 * unfragmented).
302 */
303 if (sk->sk_state == TCP_LISTEN)
304 return;
305
306 /* We don't check in the destentry if pmtu discovery is forbidden
307 * on this route. We just assume that no packet_to_big packets
308 * are send back when pmtu discovery is not active.
309 * There is a small race when the user changes this flag in the
310 * route, but I think that's acceptable.
311 */
312 if ((dst = __sk_dst_check(sk, 0)) == NULL)
313 return;
314
315 dst->ops->update_pmtu(dst, mtu);
316
317 /* Something is about to be wrong... Remember soft error
318 * for the case, if this connection will not able to recover.
319 */
320 if (mtu < dst_mtu(dst) && ip_dont_fragment(sk, dst))
321 sk->sk_err_soft = EMSGSIZE;
322
323 mtu = dst_mtu(dst);
324
325 if (inet->pmtudisc != IP_PMTUDISC_DONT &&
326 inet_csk(sk)->icsk_pmtu_cookie > mtu) {
327 tcp_sync_mss(sk, mtu);
328
329 /* Resend the TCP packet because it's
330 * clear that the old packet has been
331 * dropped. This is the new "fast" path mtu
332 * discovery.
333 */
334 tcp_simple_retransmit(sk);
335 } /* else let the usual retransmit timer handle it */
336}
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 __u32 seq;
366 __u32 remaining;
367 int err;
368 struct net *net = dev_net(icmp_skb->dev);
369
370 if (icmp_skb->len < (iph->ihl << 2) + 8) {
371 ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS);
372 return;
373 }
374
375 sk = inet_lookup(net, &tcp_hashinfo, iph->daddr, th->dest,
376 iph->saddr, th->source, inet_iif(icmp_skb));
377 if (!sk) {
378 ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS);
379 return;
380 }
381 if (sk->sk_state == TCP_TIME_WAIT) {
382 inet_twsk_put(inet_twsk(sk));
383 return;
384 }
385
386 bh_lock_sock(sk);
387 /* If too many ICMPs get dropped on busy
388 * servers this needs to be solved differently.
389 */
390 if (sock_owned_by_user(sk))
391 NET_INC_STATS_BH(net, LINUX_MIB_LOCKDROPPEDICMPS);
392
393 if (sk->sk_state == TCP_CLOSE)
394 goto out;
395
396 if (unlikely(iph->ttl < inet_sk(sk)->min_ttl)) {
397 NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP);
398 goto out;
399 }
400
401 icsk = inet_csk(sk);
402 tp = tcp_sk(sk);
403 seq = ntohl(th->seq);
404 if (sk->sk_state != TCP_LISTEN &&
405 !between(seq, tp->snd_una, tp->snd_nxt)) {
406 NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
407 goto out;
408 }
409
410 switch (type) {
411 case ICMP_SOURCE_QUENCH:
412 /* Just silently ignore these. */
413 goto out;
414 case ICMP_PARAMETERPROB:
415 err = EPROTO;
416 break;
417 case ICMP_DEST_UNREACH:
418 if (code > NR_ICMP_UNREACH)
419 goto out;
420
421 if (code == ICMP_FRAG_NEEDED) { /* PMTU discovery (RFC1191) */
422 if (!sock_owned_by_user(sk))
423 do_pmtu_discovery(sk, iph, info);
424 goto out;
425 }
426
427 err = icmp_err_convert[code].errno;
428 /* check if icmp_skb allows revert of backoff
429 * (see draft-zimmermann-tcp-lcd) */
430 if (code != ICMP_NET_UNREACH && code != ICMP_HOST_UNREACH)
431 break;
432 if (seq != tp->snd_una || !icsk->icsk_retransmits ||
433 !icsk->icsk_backoff)
434 break;
435
436 if (sock_owned_by_user(sk))
437 break;
438
439 icsk->icsk_backoff--;
440 inet_csk(sk)->icsk_rto = (tp->srtt ? __tcp_set_rto(tp) :
441 TCP_TIMEOUT_INIT) << icsk->icsk_backoff;
442 tcp_bound_rto(sk);
443
444 skb = tcp_write_queue_head(sk);
445 BUG_ON(!skb);
446
447 remaining = icsk->icsk_rto - min(icsk->icsk_rto,
448 tcp_time_stamp - TCP_SKB_CB(skb)->when);
449
450 if (remaining) {
451 inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
452 remaining, TCP_RTO_MAX);
453 } else {
454 /* RTO revert clocked out retransmission.
455 * Will retransmit now */
456 tcp_retransmit_timer(sk);
457 }
458
459 break;
460 case ICMP_TIME_EXCEEDED:
461 err = EHOSTUNREACH;
462 break;
463 default:
464 goto out;
465 }
466
467 switch (sk->sk_state) {
468 struct request_sock *req, **prev;
469 case TCP_LISTEN:
470 if (sock_owned_by_user(sk))
471 goto out;
472
473 req = inet_csk_search_req(sk, &prev, th->dest,
474 iph->daddr, iph->saddr);
475 if (!req)
476 goto out;
477
478 /* ICMPs are not backlogged, hence we cannot get
479 an established socket here.
480 */
481 WARN_ON(req->sk);
482
483 if (seq != tcp_rsk(req)->snt_isn) {
484 NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
485 goto out;
486 }
487
488 /*
489 * Still in SYN_RECV, just remove it silently.
490 * There is no good way to pass the error to the newly
491 * created socket, and POSIX does not want network
492 * errors returned from accept().
493 */
494 inet_csk_reqsk_queue_drop(sk, req, prev);
495 goto out;
496
497 case TCP_SYN_SENT:
498 case TCP_SYN_RECV: /* Cannot happen.
499 It can f.e. if SYNs crossed.
500 */
501 if (!sock_owned_by_user(sk)) {
502 sk->sk_err = err;
503
504 sk->sk_error_report(sk);
505
506 tcp_done(sk);
507 } else {
508 sk->sk_err_soft = err;
509 }
510 goto out;
511 }
512
513 /* If we've already connected we will keep trying
514 * until we time out, or the user gives up.
515 *
516 * rfc1122 4.2.3.9 allows to consider as hard errors
517 * only PROTO_UNREACH and PORT_UNREACH (well, FRAG_FAILED too,
518 * but it is obsoleted by pmtu discovery).
519 *
520 * Note, that in modern internet, where routing is unreliable
521 * and in each dark corner broken firewalls sit, sending random
522 * errors ordered by their masters even this two messages finally lose
523 * their original sense (even Linux sends invalid PORT_UNREACHs)
524 *
525 * Now we are in compliance with RFCs.
526 * --ANK (980905)
527 */
528
529 inet = inet_sk(sk);
530 if (!sock_owned_by_user(sk) && inet->recverr) {
531 sk->sk_err = err;
532 sk->sk_error_report(sk);
533 } else { /* Only an error on timeout */
534 sk->sk_err_soft = err;
535 }
536
537out:
538 bh_unlock_sock(sk);
539 sock_put(sk);
540}
541
542static void __tcp_v4_send_check(struct sk_buff *skb,
543 __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
568int tcp_v4_gso_send_check(struct sk_buff *skb)
569{
570 const struct iphdr *iph;
571 struct tcphdr *th;
572
573 if (!pskb_may_pull(skb, sizeof(*th)))
574 return -EINVAL;
575
576 iph = ip_hdr(skb);
577 th = tcp_hdr(skb);
578
579 th->check = 0;
580 skb->ip_summed = CHECKSUM_PARTIAL;
581 __tcp_v4_send_check(skb, iph->saddr, iph->daddr);
582 return 0;
583}
584
585/*
586 * This routine will send an RST to the other tcp.
587 *
588 * Someone asks: why I NEVER use socket parameters (TOS, TTL etc.)
589 * for reset.
590 * Answer: if a packet caused RST, it is not for a socket
591 * existing in our system, if it is matched to a socket,
592 * it is just duplicate segment or bug in other side's TCP.
593 * So that we build reply only basing on parameters
594 * arrived with segment.
595 * Exception: precedence violation. We do not implement it in any case.
596 */
597
598static void tcp_v4_send_reset(struct sock *sk, struct sk_buff *skb)
599{
600 const struct tcphdr *th = tcp_hdr(skb);
601 struct {
602 struct tcphdr th;
603#ifdef CONFIG_TCP_MD5SIG
604 __be32 opt[(TCPOLEN_MD5SIG_ALIGNED >> 2)];
605#endif
606 } rep;
607 struct ip_reply_arg arg;
608#ifdef CONFIG_TCP_MD5SIG
609 struct tcp_md5sig_key *key;
610 const __u8 *hash_location = NULL;
611 unsigned char newhash[16];
612 int genhash;
613 struct sock *sk1 = NULL;
614#endif
615 struct net *net;
616
617 /* Never send a reset in response to a reset. */
618 if (th->rst)
619 return;
620
621 if (skb_rtable(skb)->rt_type != RTN_LOCAL)
622 return;
623
624 /* Swap the send and the receive. */
625 memset(&rep, 0, sizeof(rep));
626 rep.th.dest = th->source;
627 rep.th.source = th->dest;
628 rep.th.doff = sizeof(struct tcphdr) / 4;
629 rep.th.rst = 1;
630
631 if (th->ack) {
632 rep.th.seq = th->ack_seq;
633 } else {
634 rep.th.ack = 1;
635 rep.th.ack_seq = htonl(ntohl(th->seq) + th->syn + th->fin +
636 skb->len - (th->doff << 2));
637 }
638
639 memset(&arg, 0, sizeof(arg));
640 arg.iov[0].iov_base = (unsigned char *)&rep;
641 arg.iov[0].iov_len = sizeof(rep.th);
642
643#ifdef CONFIG_TCP_MD5SIG
644 hash_location = tcp_parse_md5sig_option(th);
645 if (!sk && hash_location) {
646 /*
647 * active side is lost. Try to find listening socket through
648 * source port, and then find md5 key through listening socket.
649 * we are not loose security here:
650 * Incoming packet is checked with md5 hash with finding key,
651 * no RST generated if md5 hash doesn't match.
652 */
653 sk1 = __inet_lookup_listener(dev_net(skb_dst(skb)->dev),
654 &tcp_hashinfo, ip_hdr(skb)->daddr,
655 ntohs(th->source), inet_iif(skb));
656 /* don't send rst if it can't find key */
657 if (!sk1)
658 return;
659 rcu_read_lock();
660 key = tcp_md5_do_lookup(sk1, (union tcp_md5_addr *)
661 &ip_hdr(skb)->saddr, AF_INET);
662 if (!key)
663 goto release_sk1;
664
665 genhash = tcp_v4_md5_hash_skb(newhash, key, NULL, NULL, skb);
666 if (genhash || memcmp(hash_location, newhash, 16) != 0)
667 goto release_sk1;
668 } else {
669 key = sk ? tcp_md5_do_lookup(sk, (union tcp_md5_addr *)
670 &ip_hdr(skb)->saddr,
671 AF_INET) : NULL;
672 }
673
674 if (key) {
675 rep.opt[0] = htonl((TCPOPT_NOP << 24) |
676 (TCPOPT_NOP << 16) |
677 (TCPOPT_MD5SIG << 8) |
678 TCPOLEN_MD5SIG);
679 /* Update length and the length the header thinks exists */
680 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED;
681 rep.th.doff = arg.iov[0].iov_len / 4;
682
683 tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[1],
684 key, ip_hdr(skb)->saddr,
685 ip_hdr(skb)->daddr, &rep.th);
686 }
687#endif
688 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
689 ip_hdr(skb)->saddr, /* XXX */
690 arg.iov[0].iov_len, IPPROTO_TCP, 0);
691 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
692 arg.flags = (sk && inet_sk(sk)->transparent) ? IP_REPLY_ARG_NOSRCCHECK : 0;
693 /* When socket is gone, all binding information is lost.
694 * routing might fail in this case. using iif for oif to
695 * make sure we can deliver it
696 */
697 arg.bound_dev_if = sk ? sk->sk_bound_dev_if : inet_iif(skb);
698
699 net = dev_net(skb_dst(skb)->dev);
700 arg.tos = ip_hdr(skb)->tos;
701 ip_send_reply(net->ipv4.tcp_sock, skb, ip_hdr(skb)->saddr,
702 &arg, arg.iov[0].iov_len);
703
704 TCP_INC_STATS_BH(net, TCP_MIB_OUTSEGS);
705 TCP_INC_STATS_BH(net, TCP_MIB_OUTRSTS);
706
707#ifdef CONFIG_TCP_MD5SIG
708release_sk1:
709 if (sk1) {
710 rcu_read_unlock();
711 sock_put(sk1);
712 }
713#endif
714}
715
716/* The code following below sending ACKs in SYN-RECV and TIME-WAIT states
717 outside socket context is ugly, certainly. What can I do?
718 */
719
720static void tcp_v4_send_ack(struct sk_buff *skb, u32 seq, u32 ack,
721 u32 win, u32 ts, int oif,
722 struct tcp_md5sig_key *key,
723 int reply_flags, u8 tos)
724{
725 const struct tcphdr *th = tcp_hdr(skb);
726 struct {
727 struct tcphdr th;
728 __be32 opt[(TCPOLEN_TSTAMP_ALIGNED >> 2)
729#ifdef CONFIG_TCP_MD5SIG
730 + (TCPOLEN_MD5SIG_ALIGNED >> 2)
731#endif
732 ];
733 } rep;
734 struct ip_reply_arg arg;
735 struct net *net = dev_net(skb_dst(skb)->dev);
736
737 memset(&rep.th, 0, sizeof(struct tcphdr));
738 memset(&arg, 0, sizeof(arg));
739
740 arg.iov[0].iov_base = (unsigned char *)&rep;
741 arg.iov[0].iov_len = sizeof(rep.th);
742 if (ts) {
743 rep.opt[0] = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
744 (TCPOPT_TIMESTAMP << 8) |
745 TCPOLEN_TIMESTAMP);
746 rep.opt[1] = htonl(tcp_time_stamp);
747 rep.opt[2] = htonl(ts);
748 arg.iov[0].iov_len += TCPOLEN_TSTAMP_ALIGNED;
749 }
750
751 /* Swap the send and the receive. */
752 rep.th.dest = th->source;
753 rep.th.source = th->dest;
754 rep.th.doff = arg.iov[0].iov_len / 4;
755 rep.th.seq = htonl(seq);
756 rep.th.ack_seq = htonl(ack);
757 rep.th.ack = 1;
758 rep.th.window = htons(win);
759
760#ifdef CONFIG_TCP_MD5SIG
761 if (key) {
762 int offset = (ts) ? 3 : 0;
763
764 rep.opt[offset++] = htonl((TCPOPT_NOP << 24) |
765 (TCPOPT_NOP << 16) |
766 (TCPOPT_MD5SIG << 8) |
767 TCPOLEN_MD5SIG);
768 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED;
769 rep.th.doff = arg.iov[0].iov_len/4;
770
771 tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[offset],
772 key, ip_hdr(skb)->saddr,
773 ip_hdr(skb)->daddr, &rep.th);
774 }
775#endif
776 arg.flags = reply_flags;
777 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
778 ip_hdr(skb)->saddr, /* XXX */
779 arg.iov[0].iov_len, IPPROTO_TCP, 0);
780 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
781 if (oif)
782 arg.bound_dev_if = oif;
783 arg.tos = tos;
784 ip_send_reply(net->ipv4.tcp_sock, skb, ip_hdr(skb)->saddr,
785 &arg, arg.iov[0].iov_len);
786
787 TCP_INC_STATS_BH(net, TCP_MIB_OUTSEGS);
788}
789
790static void tcp_v4_timewait_ack(struct sock *sk, struct sk_buff *skb)
791{
792 struct inet_timewait_sock *tw = inet_twsk(sk);
793 struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
794
795 tcp_v4_send_ack(skb, tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
796 tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
797 tcptw->tw_ts_recent,
798 tw->tw_bound_dev_if,
799 tcp_twsk_md5_key(tcptw),
800 tw->tw_transparent ? IP_REPLY_ARG_NOSRCCHECK : 0,
801 tw->tw_tos
802 );
803
804 inet_twsk_put(tw);
805}
806
807static void tcp_v4_reqsk_send_ack(struct sock *sk, struct sk_buff *skb,
808 struct request_sock *req)
809{
810 tcp_v4_send_ack(skb, tcp_rsk(req)->snt_isn + 1,
811 tcp_rsk(req)->rcv_isn + 1, req->rcv_wnd,
812 req->ts_recent,
813 0,
814 tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&ip_hdr(skb)->daddr,
815 AF_INET),
816 inet_rsk(req)->no_srccheck ? IP_REPLY_ARG_NOSRCCHECK : 0,
817 ip_hdr(skb)->tos);
818}
819
820/*
821 * Send a SYN-ACK after having received a SYN.
822 * This still operates on a request_sock only, not on a big
823 * socket.
824 */
825static int tcp_v4_send_synack(struct sock *sk, struct dst_entry *dst,
826 struct request_sock *req,
827 struct request_values *rvp,
828 u16 queue_mapping)
829{
830 const struct inet_request_sock *ireq = inet_rsk(req);
831 struct flowi4 fl4;
832 int err = -1;
833 struct sk_buff * skb;
834
835 /* First, grab a route. */
836 if (!dst && (dst = inet_csk_route_req(sk, &fl4, req)) == NULL)
837 return -1;
838
839 skb = tcp_make_synack(sk, dst, req, rvp);
840
841 if (skb) {
842 __tcp_v4_send_check(skb, ireq->loc_addr, ireq->rmt_addr);
843
844 skb_set_queue_mapping(skb, queue_mapping);
845 err = ip_build_and_send_pkt(skb, sk, ireq->loc_addr,
846 ireq->rmt_addr,
847 ireq->opt);
848 err = net_xmit_eval(err);
849 }
850
851 dst_release(dst);
852 return err;
853}
854
855static int tcp_v4_rtx_synack(struct sock *sk, struct request_sock *req,
856 struct request_values *rvp)
857{
858 TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_RETRANSSEGS);
859 return tcp_v4_send_synack(sk, NULL, req, rvp, 0);
860}
861
862/*
863 * IPv4 request_sock destructor.
864 */
865static void tcp_v4_reqsk_destructor(struct request_sock *req)
866{
867 kfree(inet_rsk(req)->opt);
868}
869
870/*
871 * Return true if a syncookie should be sent
872 */
873bool tcp_syn_flood_action(struct sock *sk,
874 const struct sk_buff *skb,
875 const char *proto)
876{
877 const char *msg = "Dropping request";
878 bool want_cookie = false;
879 struct listen_sock *lopt;
880
881
882
883#ifdef CONFIG_SYN_COOKIES
884 if (sysctl_tcp_syncookies) {
885 msg = "Sending cookies";
886 want_cookie = true;
887 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPREQQFULLDOCOOKIES);
888 } else
889#endif
890 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPREQQFULLDROP);
891
892 lopt = inet_csk(sk)->icsk_accept_queue.listen_opt;
893 if (!lopt->synflood_warned) {
894 lopt->synflood_warned = 1;
895 pr_info("%s: Possible SYN flooding on port %d. %s. Check SNMP counters.\n",
896 proto, ntohs(tcp_hdr(skb)->dest), msg);
897 }
898 return want_cookie;
899}
900EXPORT_SYMBOL(tcp_syn_flood_action);
901
902/*
903 * Save and compile IPv4 options into the request_sock if needed.
904 */
905static struct ip_options_rcu *tcp_v4_save_options(struct sock *sk,
906 struct sk_buff *skb)
907{
908 const struct ip_options *opt = &(IPCB(skb)->opt);
909 struct ip_options_rcu *dopt = NULL;
910
911 if (opt && opt->optlen) {
912 int opt_size = sizeof(*dopt) + opt->optlen;
913
914 dopt = kmalloc(opt_size, GFP_ATOMIC);
915 if (dopt) {
916 if (ip_options_echo(&dopt->opt, skb)) {
917 kfree(dopt);
918 dopt = NULL;
919 }
920 }
921 }
922 return dopt;
923}
924
925#ifdef CONFIG_TCP_MD5SIG
926/*
927 * RFC2385 MD5 checksumming requires a mapping of
928 * IP address->MD5 Key.
929 * We need to maintain these in the sk structure.
930 */
931
932/* Find the Key structure for an address. */
933struct tcp_md5sig_key *tcp_md5_do_lookup(struct sock *sk,
934 const union tcp_md5_addr *addr,
935 int family)
936{
937 struct tcp_sock *tp = tcp_sk(sk);
938 struct tcp_md5sig_key *key;
939 struct hlist_node *pos;
940 unsigned int size = sizeof(struct in_addr);
941 struct tcp_md5sig_info *md5sig;
942
943 /* caller either holds rcu_read_lock() or socket lock */
944 md5sig = rcu_dereference_check(tp->md5sig_info,
945 sock_owned_by_user(sk) ||
946 lockdep_is_held(&sk->sk_lock.slock));
947 if (!md5sig)
948 return NULL;
949#if IS_ENABLED(CONFIG_IPV6)
950 if (family == AF_INET6)
951 size = sizeof(struct in6_addr);
952#endif
953 hlist_for_each_entry_rcu(key, pos, &md5sig->head, node) {
954 if (key->family != family)
955 continue;
956 if (!memcmp(&key->addr, addr, size))
957 return key;
958 }
959 return NULL;
960}
961EXPORT_SYMBOL(tcp_md5_do_lookup);
962
963struct tcp_md5sig_key *tcp_v4_md5_lookup(struct sock *sk,
964 struct sock *addr_sk)
965{
966 union tcp_md5_addr *addr;
967
968 addr = (union tcp_md5_addr *)&inet_sk(addr_sk)->inet_daddr;
969 return tcp_md5_do_lookup(sk, addr, AF_INET);
970}
971EXPORT_SYMBOL(tcp_v4_md5_lookup);
972
973static struct tcp_md5sig_key *tcp_v4_reqsk_md5_lookup(struct sock *sk,
974 struct request_sock *req)
975{
976 union tcp_md5_addr *addr;
977
978 addr = (union tcp_md5_addr *)&inet_rsk(req)->rmt_addr;
979 return tcp_md5_do_lookup(sk, addr, AF_INET);
980}
981
982/* This can be called on a newly created socket, from other files */
983int tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr,
984 int family, const u8 *newkey, u8 newkeylen, gfp_t gfp)
985{
986 /* Add Key to the list */
987 struct tcp_md5sig_key *key;
988 struct tcp_sock *tp = tcp_sk(sk);
989 struct tcp_md5sig_info *md5sig;
990
991 key = tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&addr, AF_INET);
992 if (key) {
993 /* Pre-existing entry - just update that one. */
994 memcpy(key->key, newkey, newkeylen);
995 key->keylen = newkeylen;
996 return 0;
997 }
998
999 md5sig = rcu_dereference_protected(tp->md5sig_info,
1000 sock_owned_by_user(sk));
1001 if (!md5sig) {
1002 md5sig = kmalloc(sizeof(*md5sig), gfp);
1003 if (!md5sig)
1004 return -ENOMEM;
1005
1006 sk_nocaps_add(sk, NETIF_F_GSO_MASK);
1007 INIT_HLIST_HEAD(&md5sig->head);
1008 rcu_assign_pointer(tp->md5sig_info, md5sig);
1009 }
1010
1011 key = sock_kmalloc(sk, sizeof(*key), gfp);
1012 if (!key)
1013 return -ENOMEM;
1014 if (hlist_empty(&md5sig->head) && !tcp_alloc_md5sig_pool(sk)) {
1015 sock_kfree_s(sk, key, sizeof(*key));
1016 return -ENOMEM;
1017 }
1018
1019 memcpy(key->key, newkey, newkeylen);
1020 key->keylen = newkeylen;
1021 key->family = family;
1022 memcpy(&key->addr, addr,
1023 (family == AF_INET6) ? sizeof(struct in6_addr) :
1024 sizeof(struct in_addr));
1025 hlist_add_head_rcu(&key->node, &md5sig->head);
1026 return 0;
1027}
1028EXPORT_SYMBOL(tcp_md5_do_add);
1029
1030int tcp_md5_do_del(struct sock *sk, const union tcp_md5_addr *addr, int family)
1031{
1032 struct tcp_sock *tp = tcp_sk(sk);
1033 struct tcp_md5sig_key *key;
1034 struct tcp_md5sig_info *md5sig;
1035
1036 key = tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&addr, AF_INET);
1037 if (!key)
1038 return -ENOENT;
1039 hlist_del_rcu(&key->node);
1040 atomic_sub(sizeof(*key), &sk->sk_omem_alloc);
1041 kfree_rcu(key, rcu);
1042 md5sig = rcu_dereference_protected(tp->md5sig_info,
1043 sock_owned_by_user(sk));
1044 if (hlist_empty(&md5sig->head))
1045 tcp_free_md5sig_pool();
1046 return 0;
1047}
1048EXPORT_SYMBOL(tcp_md5_do_del);
1049
1050void tcp_clear_md5_list(struct sock *sk)
1051{
1052 struct tcp_sock *tp = tcp_sk(sk);
1053 struct tcp_md5sig_key *key;
1054 struct hlist_node *pos, *n;
1055 struct tcp_md5sig_info *md5sig;
1056
1057 md5sig = rcu_dereference_protected(tp->md5sig_info, 1);
1058
1059 if (!hlist_empty(&md5sig->head))
1060 tcp_free_md5sig_pool();
1061 hlist_for_each_entry_safe(key, pos, n, &md5sig->head, node) {
1062 hlist_del_rcu(&key->node);
1063 atomic_sub(sizeof(*key), &sk->sk_omem_alloc);
1064 kfree_rcu(key, rcu);
1065 }
1066}
1067
1068static int tcp_v4_parse_md5_keys(struct sock *sk, char __user *optval,
1069 int optlen)
1070{
1071 struct tcp_md5sig cmd;
1072 struct sockaddr_in *sin = (struct sockaddr_in *)&cmd.tcpm_addr;
1073
1074 if (optlen < sizeof(cmd))
1075 return -EINVAL;
1076
1077 if (copy_from_user(&cmd, optval, sizeof(cmd)))
1078 return -EFAULT;
1079
1080 if (sin->sin_family != AF_INET)
1081 return -EINVAL;
1082
1083 if (!cmd.tcpm_key || !cmd.tcpm_keylen)
1084 return tcp_md5_do_del(sk, (union tcp_md5_addr *)&sin->sin_addr.s_addr,
1085 AF_INET);
1086
1087 if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN)
1088 return -EINVAL;
1089
1090 return tcp_md5_do_add(sk, (union tcp_md5_addr *)&sin->sin_addr.s_addr,
1091 AF_INET, cmd.tcpm_key, cmd.tcpm_keylen,
1092 GFP_KERNEL);
1093}
1094
1095static int tcp_v4_md5_hash_pseudoheader(struct tcp_md5sig_pool *hp,
1096 __be32 daddr, __be32 saddr, int nbytes)
1097{
1098 struct tcp4_pseudohdr *bp;
1099 struct scatterlist sg;
1100
1101 bp = &hp->md5_blk.ip4;
1102
1103 /*
1104 * 1. the TCP pseudo-header (in the order: source IP address,
1105 * destination IP address, zero-padded protocol number, and
1106 * segment length)
1107 */
1108 bp->saddr = saddr;
1109 bp->daddr = daddr;
1110 bp->pad = 0;
1111 bp->protocol = IPPROTO_TCP;
1112 bp->len = cpu_to_be16(nbytes);
1113
1114 sg_init_one(&sg, bp, sizeof(*bp));
1115 return crypto_hash_update(&hp->md5_desc, &sg, sizeof(*bp));
1116}
1117
1118static int tcp_v4_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key,
1119 __be32 daddr, __be32 saddr, const struct tcphdr *th)
1120{
1121 struct tcp_md5sig_pool *hp;
1122 struct hash_desc *desc;
1123
1124 hp = tcp_get_md5sig_pool();
1125 if (!hp)
1126 goto clear_hash_noput;
1127 desc = &hp->md5_desc;
1128
1129 if (crypto_hash_init(desc))
1130 goto clear_hash;
1131 if (tcp_v4_md5_hash_pseudoheader(hp, daddr, saddr, th->doff << 2))
1132 goto clear_hash;
1133 if (tcp_md5_hash_header(hp, th))
1134 goto clear_hash;
1135 if (tcp_md5_hash_key(hp, key))
1136 goto clear_hash;
1137 if (crypto_hash_final(desc, md5_hash))
1138 goto clear_hash;
1139
1140 tcp_put_md5sig_pool();
1141 return 0;
1142
1143clear_hash:
1144 tcp_put_md5sig_pool();
1145clear_hash_noput:
1146 memset(md5_hash, 0, 16);
1147 return 1;
1148}
1149
1150int tcp_v4_md5_hash_skb(char *md5_hash, struct tcp_md5sig_key *key,
1151 const struct sock *sk, const struct request_sock *req,
1152 const struct sk_buff *skb)
1153{
1154 struct tcp_md5sig_pool *hp;
1155 struct hash_desc *desc;
1156 const struct tcphdr *th = tcp_hdr(skb);
1157 __be32 saddr, daddr;
1158
1159 if (sk) {
1160 saddr = inet_sk(sk)->inet_saddr;
1161 daddr = inet_sk(sk)->inet_daddr;
1162 } else if (req) {
1163 saddr = inet_rsk(req)->loc_addr;
1164 daddr = inet_rsk(req)->rmt_addr;
1165 } else {
1166 const struct iphdr *iph = ip_hdr(skb);
1167 saddr = iph->saddr;
1168 daddr = iph->daddr;
1169 }
1170
1171 hp = tcp_get_md5sig_pool();
1172 if (!hp)
1173 goto clear_hash_noput;
1174 desc = &hp->md5_desc;
1175
1176 if (crypto_hash_init(desc))
1177 goto clear_hash;
1178
1179 if (tcp_v4_md5_hash_pseudoheader(hp, daddr, saddr, skb->len))
1180 goto clear_hash;
1181 if (tcp_md5_hash_header(hp, th))
1182 goto clear_hash;
1183 if (tcp_md5_hash_skb_data(hp, skb, th->doff << 2))
1184 goto clear_hash;
1185 if (tcp_md5_hash_key(hp, key))
1186 goto clear_hash;
1187 if (crypto_hash_final(desc, md5_hash))
1188 goto clear_hash;
1189
1190 tcp_put_md5sig_pool();
1191 return 0;
1192
1193clear_hash:
1194 tcp_put_md5sig_pool();
1195clear_hash_noput:
1196 memset(md5_hash, 0, 16);
1197 return 1;
1198}
1199EXPORT_SYMBOL(tcp_v4_md5_hash_skb);
1200
1201static bool tcp_v4_inbound_md5_hash(struct sock *sk, const struct sk_buff *skb)
1202{
1203 /*
1204 * This gets called for each TCP segment that arrives
1205 * so we want to be efficient.
1206 * We have 3 drop cases:
1207 * o No MD5 hash and one expected.
1208 * o MD5 hash and we're not expecting one.
1209 * o MD5 hash and its wrong.
1210 */
1211 const __u8 *hash_location = NULL;
1212 struct tcp_md5sig_key *hash_expected;
1213 const struct iphdr *iph = ip_hdr(skb);
1214 const struct tcphdr *th = tcp_hdr(skb);
1215 int genhash;
1216 unsigned char newhash[16];
1217
1218 hash_expected = tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&iph->saddr,
1219 AF_INET);
1220 hash_location = tcp_parse_md5sig_option(th);
1221
1222 /* We've parsed the options - do we have a hash? */
1223 if (!hash_expected && !hash_location)
1224 return false;
1225
1226 if (hash_expected && !hash_location) {
1227 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5NOTFOUND);
1228 return true;
1229 }
1230
1231 if (!hash_expected && hash_location) {
1232 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5UNEXPECTED);
1233 return true;
1234 }
1235
1236 /* Okay, so this is hash_expected and hash_location -
1237 * so we need to calculate the checksum.
1238 */
1239 genhash = tcp_v4_md5_hash_skb(newhash,
1240 hash_expected,
1241 NULL, NULL, skb);
1242
1243 if (genhash || memcmp(hash_location, newhash, 16) != 0) {
1244 net_info_ratelimited("MD5 Hash failed for (%pI4, %d)->(%pI4, %d)%s\n",
1245 &iph->saddr, ntohs(th->source),
1246 &iph->daddr, ntohs(th->dest),
1247 genhash ? " tcp_v4_calc_md5_hash failed"
1248 : "");
1249 return true;
1250 }
1251 return false;
1252}
1253
1254#endif
1255
1256struct request_sock_ops tcp_request_sock_ops __read_mostly = {
1257 .family = PF_INET,
1258 .obj_size = sizeof(struct tcp_request_sock),
1259 .rtx_syn_ack = tcp_v4_rtx_synack,
1260 .send_ack = tcp_v4_reqsk_send_ack,
1261 .destructor = tcp_v4_reqsk_destructor,
1262 .send_reset = tcp_v4_send_reset,
1263 .syn_ack_timeout = tcp_syn_ack_timeout,
1264};
1265
1266#ifdef CONFIG_TCP_MD5SIG
1267static const struct tcp_request_sock_ops tcp_request_sock_ipv4_ops = {
1268 .md5_lookup = tcp_v4_reqsk_md5_lookup,
1269 .calc_md5_hash = tcp_v4_md5_hash_skb,
1270};
1271#endif
1272
1273int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
1274{
1275 struct tcp_extend_values tmp_ext;
1276 struct tcp_options_received tmp_opt;
1277 const u8 *hash_location;
1278 struct request_sock *req;
1279 struct inet_request_sock *ireq;
1280 struct tcp_sock *tp = tcp_sk(sk);
1281 struct dst_entry *dst = NULL;
1282 __be32 saddr = ip_hdr(skb)->saddr;
1283 __be32 daddr = ip_hdr(skb)->daddr;
1284 __u32 isn = TCP_SKB_CB(skb)->when;
1285 bool want_cookie = false;
1286
1287 /* Never answer to SYNs send to broadcast or multicast */
1288 if (skb_rtable(skb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
1289 goto drop;
1290
1291 /* TW buckets are converted to open requests without
1292 * limitations, they conserve resources and peer is
1293 * evidently real one.
1294 */
1295 if (inet_csk_reqsk_queue_is_full(sk) && !isn) {
1296 want_cookie = tcp_syn_flood_action(sk, skb, "TCP");
1297 if (!want_cookie)
1298 goto drop;
1299 }
1300
1301 /* Accept backlog is full. If we have already queued enough
1302 * of warm entries in syn queue, drop request. It is better than
1303 * clogging syn queue with openreqs with exponentially increasing
1304 * timeout.
1305 */
1306 if (sk_acceptq_is_full(sk) && inet_csk_reqsk_queue_young(sk) > 1)
1307 goto drop;
1308
1309 req = inet_reqsk_alloc(&tcp_request_sock_ops);
1310 if (!req)
1311 goto drop;
1312
1313#ifdef CONFIG_TCP_MD5SIG
1314 tcp_rsk(req)->af_specific = &tcp_request_sock_ipv4_ops;
1315#endif
1316
1317 tcp_clear_options(&tmp_opt);
1318 tmp_opt.mss_clamp = TCP_MSS_DEFAULT;
1319 tmp_opt.user_mss = tp->rx_opt.user_mss;
1320 tcp_parse_options(skb, &tmp_opt, &hash_location, 0);
1321
1322 if (tmp_opt.cookie_plus > 0 &&
1323 tmp_opt.saw_tstamp &&
1324 !tp->rx_opt.cookie_out_never &&
1325 (sysctl_tcp_cookie_size > 0 ||
1326 (tp->cookie_values != NULL &&
1327 tp->cookie_values->cookie_desired > 0))) {
1328 u8 *c;
1329 u32 *mess = &tmp_ext.cookie_bakery[COOKIE_DIGEST_WORDS];
1330 int l = tmp_opt.cookie_plus - TCPOLEN_COOKIE_BASE;
1331
1332 if (tcp_cookie_generator(&tmp_ext.cookie_bakery[0]) != 0)
1333 goto drop_and_release;
1334
1335 /* Secret recipe starts with IP addresses */
1336 *mess++ ^= (__force u32)daddr;
1337 *mess++ ^= (__force u32)saddr;
1338
1339 /* plus variable length Initiator Cookie */
1340 c = (u8 *)mess;
1341 while (l-- > 0)
1342 *c++ ^= *hash_location++;
1343
1344 want_cookie = false; /* not our kind of cookie */
1345 tmp_ext.cookie_out_never = 0; /* false */
1346 tmp_ext.cookie_plus = tmp_opt.cookie_plus;
1347 } else if (!tp->rx_opt.cookie_in_always) {
1348 /* redundant indications, but ensure initialization. */
1349 tmp_ext.cookie_out_never = 1; /* true */
1350 tmp_ext.cookie_plus = 0;
1351 } else {
1352 goto drop_and_release;
1353 }
1354 tmp_ext.cookie_in_always = tp->rx_opt.cookie_in_always;
1355
1356 if (want_cookie && !tmp_opt.saw_tstamp)
1357 tcp_clear_options(&tmp_opt);
1358
1359 tmp_opt.tstamp_ok = tmp_opt.saw_tstamp;
1360 tcp_openreq_init(req, &tmp_opt, skb);
1361
1362 ireq = inet_rsk(req);
1363 ireq->loc_addr = daddr;
1364 ireq->rmt_addr = saddr;
1365 ireq->no_srccheck = inet_sk(sk)->transparent;
1366 ireq->opt = tcp_v4_save_options(sk, skb);
1367
1368 if (security_inet_conn_request(sk, skb, req))
1369 goto drop_and_free;
1370
1371 if (!want_cookie || tmp_opt.tstamp_ok)
1372 TCP_ECN_create_request(req, skb);
1373
1374 if (want_cookie) {
1375 isn = cookie_v4_init_sequence(sk, skb, &req->mss);
1376 req->cookie_ts = tmp_opt.tstamp_ok;
1377 } else if (!isn) {
1378 struct inet_peer *peer = NULL;
1379 struct flowi4 fl4;
1380
1381 /* VJ's idea. We save last timestamp seen
1382 * from the destination in peer table, when entering
1383 * state TIME-WAIT, and check against it before
1384 * accepting new connection request.
1385 *
1386 * If "isn" is not zero, this request hit alive
1387 * timewait bucket, so that all the necessary checks
1388 * are made in the function processing timewait state.
1389 */
1390 if (tmp_opt.saw_tstamp &&
1391 tcp_death_row.sysctl_tw_recycle &&
1392 (dst = inet_csk_route_req(sk, &fl4, req)) != NULL &&
1393 fl4.daddr == saddr &&
1394 (peer = rt_get_peer((struct rtable *)dst, fl4.daddr)) != NULL) {
1395 inet_peer_refcheck(peer);
1396 if ((u32)get_seconds() - peer->tcp_ts_stamp < TCP_PAWS_MSL &&
1397 (s32)(peer->tcp_ts - req->ts_recent) >
1398 TCP_PAWS_WINDOW) {
1399 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_PAWSPASSIVEREJECTED);
1400 goto drop_and_release;
1401 }
1402 }
1403 /* Kill the following clause, if you dislike this way. */
1404 else if (!sysctl_tcp_syncookies &&
1405 (sysctl_max_syn_backlog - inet_csk_reqsk_queue_len(sk) <
1406 (sysctl_max_syn_backlog >> 2)) &&
1407 (!peer || !peer->tcp_ts_stamp) &&
1408 (!dst || !dst_metric(dst, RTAX_RTT))) {
1409 /* Without syncookies last quarter of
1410 * backlog is filled with destinations,
1411 * proven to be alive.
1412 * It means that we continue to communicate
1413 * to destinations, already remembered
1414 * to the moment of synflood.
1415 */
1416 LIMIT_NETDEBUG(KERN_DEBUG pr_fmt("drop open request from %pI4/%u\n"),
1417 &saddr, ntohs(tcp_hdr(skb)->source));
1418 goto drop_and_release;
1419 }
1420
1421 isn = tcp_v4_init_sequence(skb);
1422 }
1423 tcp_rsk(req)->snt_isn = isn;
1424 tcp_rsk(req)->snt_synack = tcp_time_stamp;
1425
1426 if (tcp_v4_send_synack(sk, dst, req,
1427 (struct request_values *)&tmp_ext,
1428 skb_get_queue_mapping(skb)) ||
1429 want_cookie)
1430 goto drop_and_free;
1431
1432 inet_csk_reqsk_queue_hash_add(sk, req, TCP_TIMEOUT_INIT);
1433 return 0;
1434
1435drop_and_release:
1436 dst_release(dst);
1437drop_and_free:
1438 reqsk_free(req);
1439drop:
1440 return 0;
1441}
1442EXPORT_SYMBOL(tcp_v4_conn_request);
1443
1444
1445/*
1446 * The three way handshake has completed - we got a valid synack -
1447 * now create the new socket.
1448 */
1449struct sock *tcp_v4_syn_recv_sock(struct sock *sk, struct sk_buff *skb,
1450 struct request_sock *req,
1451 struct dst_entry *dst)
1452{
1453 struct inet_request_sock *ireq;
1454 struct inet_sock *newinet;
1455 struct tcp_sock *newtp;
1456 struct sock *newsk;
1457#ifdef CONFIG_TCP_MD5SIG
1458 struct tcp_md5sig_key *key;
1459#endif
1460 struct ip_options_rcu *inet_opt;
1461
1462 if (sk_acceptq_is_full(sk))
1463 goto exit_overflow;
1464
1465 newsk = tcp_create_openreq_child(sk, req, skb);
1466 if (!newsk)
1467 goto exit_nonewsk;
1468
1469 newsk->sk_gso_type = SKB_GSO_TCPV4;
1470
1471 newtp = tcp_sk(newsk);
1472 newinet = inet_sk(newsk);
1473 ireq = inet_rsk(req);
1474 newinet->inet_daddr = ireq->rmt_addr;
1475 newinet->inet_rcv_saddr = ireq->loc_addr;
1476 newinet->inet_saddr = ireq->loc_addr;
1477 inet_opt = ireq->opt;
1478 rcu_assign_pointer(newinet->inet_opt, inet_opt);
1479 ireq->opt = NULL;
1480 newinet->mc_index = inet_iif(skb);
1481 newinet->mc_ttl = ip_hdr(skb)->ttl;
1482 newinet->rcv_tos = ip_hdr(skb)->tos;
1483 inet_csk(newsk)->icsk_ext_hdr_len = 0;
1484 if (inet_opt)
1485 inet_csk(newsk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
1486 newinet->inet_id = newtp->write_seq ^ jiffies;
1487
1488 if (!dst) {
1489 dst = inet_csk_route_child_sock(sk, newsk, req);
1490 if (!dst)
1491 goto put_and_exit;
1492 } else {
1493 /* syncookie case : see end of cookie_v4_check() */
1494 }
1495 sk_setup_caps(newsk, dst);
1496
1497 tcp_mtup_init(newsk);
1498 tcp_sync_mss(newsk, dst_mtu(dst));
1499 newtp->advmss = dst_metric_advmss(dst);
1500 if (tcp_sk(sk)->rx_opt.user_mss &&
1501 tcp_sk(sk)->rx_opt.user_mss < newtp->advmss)
1502 newtp->advmss = tcp_sk(sk)->rx_opt.user_mss;
1503
1504 tcp_initialize_rcv_mss(newsk);
1505 if (tcp_rsk(req)->snt_synack)
1506 tcp_valid_rtt_meas(newsk,
1507 tcp_time_stamp - tcp_rsk(req)->snt_synack);
1508 newtp->total_retrans = req->retrans;
1509
1510#ifdef CONFIG_TCP_MD5SIG
1511 /* Copy over the MD5 key from the original socket */
1512 key = tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&newinet->inet_daddr,
1513 AF_INET);
1514 if (key != NULL) {
1515 /*
1516 * We're using one, so create a matching key
1517 * on the newsk structure. If we fail to get
1518 * memory, then we end up not copying the key
1519 * across. Shucks.
1520 */
1521 tcp_md5_do_add(newsk, (union tcp_md5_addr *)&newinet->inet_daddr,
1522 AF_INET, key->key, key->keylen, GFP_ATOMIC);
1523 sk_nocaps_add(newsk, NETIF_F_GSO_MASK);
1524 }
1525#endif
1526
1527 if (__inet_inherit_port(sk, newsk) < 0)
1528 goto put_and_exit;
1529 __inet_hash_nolisten(newsk, NULL);
1530
1531 return newsk;
1532
1533exit_overflow:
1534 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
1535exit_nonewsk:
1536 dst_release(dst);
1537exit:
1538 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
1539 return NULL;
1540put_and_exit:
1541 tcp_clear_xmit_timers(newsk);
1542 tcp_cleanup_congestion_control(newsk);
1543 bh_unlock_sock(newsk);
1544 sock_put(newsk);
1545 goto exit;
1546}
1547EXPORT_SYMBOL(tcp_v4_syn_recv_sock);
1548
1549static struct sock *tcp_v4_hnd_req(struct sock *sk, struct sk_buff *skb)
1550{
1551 struct tcphdr *th = tcp_hdr(skb);
1552 const struct iphdr *iph = ip_hdr(skb);
1553 struct sock *nsk;
1554 struct request_sock **prev;
1555 /* Find possible connection requests. */
1556 struct request_sock *req = inet_csk_search_req(sk, &prev, th->source,
1557 iph->saddr, iph->daddr);
1558 if (req)
1559 return tcp_check_req(sk, skb, req, prev);
1560
1561 nsk = inet_lookup_established(sock_net(sk), &tcp_hashinfo, iph->saddr,
1562 th->source, iph->daddr, th->dest, inet_iif(skb));
1563
1564 if (nsk) {
1565 if (nsk->sk_state != TCP_TIME_WAIT) {
1566 bh_lock_sock(nsk);
1567 return nsk;
1568 }
1569 inet_twsk_put(inet_twsk(nsk));
1570 return NULL;
1571 }
1572
1573#ifdef CONFIG_SYN_COOKIES
1574 if (!th->syn)
1575 sk = cookie_v4_check(sk, skb, &(IPCB(skb)->opt));
1576#endif
1577 return sk;
1578}
1579
1580static __sum16 tcp_v4_checksum_init(struct sk_buff *skb)
1581{
1582 const struct iphdr *iph = ip_hdr(skb);
1583
1584 if (skb->ip_summed == CHECKSUM_COMPLETE) {
1585 if (!tcp_v4_check(skb->len, iph->saddr,
1586 iph->daddr, skb->csum)) {
1587 skb->ip_summed = CHECKSUM_UNNECESSARY;
1588 return 0;
1589 }
1590 }
1591
1592 skb->csum = csum_tcpudp_nofold(iph->saddr, iph->daddr,
1593 skb->len, IPPROTO_TCP, 0);
1594
1595 if (skb->len <= 76) {
1596 return __skb_checksum_complete(skb);
1597 }
1598 return 0;
1599}
1600
1601
1602/* The socket must have it's spinlock held when we get
1603 * here.
1604 *
1605 * We have a potential double-lock case here, so even when
1606 * doing backlog processing we use the BH locking scheme.
1607 * This is because we cannot sleep with the original spinlock
1608 * held.
1609 */
1610int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
1611{
1612 struct sock *rsk;
1613#ifdef CONFIG_TCP_MD5SIG
1614 /*
1615 * We really want to reject the packet as early as possible
1616 * if:
1617 * o We're expecting an MD5'd packet and this is no MD5 tcp option
1618 * o There is an MD5 option and we're not expecting one
1619 */
1620 if (tcp_v4_inbound_md5_hash(sk, skb))
1621 goto discard;
1622#endif
1623
1624 if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
1625 sock_rps_save_rxhash(sk, skb);
1626 if (tcp_rcv_established(sk, skb, tcp_hdr(skb), skb->len)) {
1627 rsk = sk;
1628 goto reset;
1629 }
1630 return 0;
1631 }
1632
1633 if (skb->len < tcp_hdrlen(skb) || tcp_checksum_complete(skb))
1634 goto csum_err;
1635
1636 if (sk->sk_state == TCP_LISTEN) {
1637 struct sock *nsk = tcp_v4_hnd_req(sk, skb);
1638 if (!nsk)
1639 goto discard;
1640
1641 if (nsk != sk) {
1642 sock_rps_save_rxhash(nsk, skb);
1643 if (tcp_child_process(sk, nsk, skb)) {
1644 rsk = nsk;
1645 goto reset;
1646 }
1647 return 0;
1648 }
1649 } else
1650 sock_rps_save_rxhash(sk, skb);
1651
1652 if (tcp_rcv_state_process(sk, skb, tcp_hdr(skb), skb->len)) {
1653 rsk = sk;
1654 goto reset;
1655 }
1656 return 0;
1657
1658reset:
1659 tcp_v4_send_reset(rsk, skb);
1660discard:
1661 kfree_skb(skb);
1662 /* Be careful here. If this function gets more complicated and
1663 * gcc suffers from register pressure on the x86, sk (in %ebx)
1664 * might be destroyed here. This current version compiles correctly,
1665 * but you have been warned.
1666 */
1667 return 0;
1668
1669csum_err:
1670 TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_INERRS);
1671 goto discard;
1672}
1673EXPORT_SYMBOL(tcp_v4_do_rcv);
1674
1675/*
1676 * From tcp_input.c
1677 */
1678
1679int tcp_v4_rcv(struct sk_buff *skb)
1680{
1681 const struct iphdr *iph;
1682 const struct tcphdr *th;
1683 struct sock *sk;
1684 int ret;
1685 struct net *net = dev_net(skb->dev);
1686
1687 if (skb->pkt_type != PACKET_HOST)
1688 goto discard_it;
1689
1690 /* Count it even if it's bad */
1691 TCP_INC_STATS_BH(net, TCP_MIB_INSEGS);
1692
1693 if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
1694 goto discard_it;
1695
1696 th = tcp_hdr(skb);
1697
1698 if (th->doff < sizeof(struct tcphdr) / 4)
1699 goto bad_packet;
1700 if (!pskb_may_pull(skb, th->doff * 4))
1701 goto discard_it;
1702
1703 /* An explanation is required here, I think.
1704 * Packet length and doff are validated by header prediction,
1705 * provided case of th->doff==0 is eliminated.
1706 * So, we defer the checks. */
1707 if (!skb_csum_unnecessary(skb) && tcp_v4_checksum_init(skb))
1708 goto bad_packet;
1709
1710 th = tcp_hdr(skb);
1711 iph = ip_hdr(skb);
1712 TCP_SKB_CB(skb)->seq = ntohl(th->seq);
1713 TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
1714 skb->len - th->doff * 4);
1715 TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
1716 TCP_SKB_CB(skb)->when = 0;
1717 TCP_SKB_CB(skb)->ip_dsfield = ipv4_get_dsfield(iph);
1718 TCP_SKB_CB(skb)->sacked = 0;
1719
1720 sk = __inet_lookup_skb(&tcp_hashinfo, skb, th->source, th->dest);
1721 if (!sk)
1722 goto no_tcp_socket;
1723
1724process:
1725 if (sk->sk_state == TCP_TIME_WAIT)
1726 goto do_time_wait;
1727
1728 if (unlikely(iph->ttl < inet_sk(sk)->min_ttl)) {
1729 NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP);
1730 goto discard_and_relse;
1731 }
1732
1733 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
1734 goto discard_and_relse;
1735 nf_reset(skb);
1736
1737 if (sk_filter(sk, skb))
1738 goto discard_and_relse;
1739
1740 skb->dev = NULL;
1741
1742 bh_lock_sock_nested(sk);
1743 ret = 0;
1744 if (!sock_owned_by_user(sk)) {
1745#ifdef CONFIG_NET_DMA
1746 struct tcp_sock *tp = tcp_sk(sk);
1747 if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list)
1748 tp->ucopy.dma_chan = net_dma_find_channel();
1749 if (tp->ucopy.dma_chan)
1750 ret = tcp_v4_do_rcv(sk, skb);
1751 else
1752#endif
1753 {
1754 if (!tcp_prequeue(sk, skb))
1755 ret = tcp_v4_do_rcv(sk, skb);
1756 }
1757 } else if (unlikely(sk_add_backlog(sk, skb,
1758 sk->sk_rcvbuf + sk->sk_sndbuf))) {
1759 bh_unlock_sock(sk);
1760 NET_INC_STATS_BH(net, LINUX_MIB_TCPBACKLOGDROP);
1761 goto discard_and_relse;
1762 }
1763 bh_unlock_sock(sk);
1764
1765 sock_put(sk);
1766
1767 return ret;
1768
1769no_tcp_socket:
1770 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
1771 goto discard_it;
1772
1773 if (skb->len < (th->doff << 2) || tcp_checksum_complete(skb)) {
1774bad_packet:
1775 TCP_INC_STATS_BH(net, TCP_MIB_INERRS);
1776 } else {
1777 tcp_v4_send_reset(NULL, skb);
1778 }
1779
1780discard_it:
1781 /* Discard frame. */
1782 kfree_skb(skb);
1783 return 0;
1784
1785discard_and_relse:
1786 sock_put(sk);
1787 goto discard_it;
1788
1789do_time_wait:
1790 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
1791 inet_twsk_put(inet_twsk(sk));
1792 goto discard_it;
1793 }
1794
1795 if (skb->len < (th->doff << 2) || tcp_checksum_complete(skb)) {
1796 TCP_INC_STATS_BH(net, TCP_MIB_INERRS);
1797 inet_twsk_put(inet_twsk(sk));
1798 goto discard_it;
1799 }
1800 switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) {
1801 case TCP_TW_SYN: {
1802 struct sock *sk2 = inet_lookup_listener(dev_net(skb->dev),
1803 &tcp_hashinfo,
1804 iph->daddr, th->dest,
1805 inet_iif(skb));
1806 if (sk2) {
1807 inet_twsk_deschedule(inet_twsk(sk), &tcp_death_row);
1808 inet_twsk_put(inet_twsk(sk));
1809 sk = sk2;
1810 goto process;
1811 }
1812 /* Fall through to ACK */
1813 }
1814 case TCP_TW_ACK:
1815 tcp_v4_timewait_ack(sk, skb);
1816 break;
1817 case TCP_TW_RST:
1818 goto no_tcp_socket;
1819 case TCP_TW_SUCCESS:;
1820 }
1821 goto discard_it;
1822}
1823
1824struct inet_peer *tcp_v4_get_peer(struct sock *sk, bool *release_it)
1825{
1826 struct rtable *rt = (struct rtable *) __sk_dst_get(sk);
1827 struct inet_sock *inet = inet_sk(sk);
1828 struct inet_peer *peer;
1829
1830 if (!rt ||
1831 inet->cork.fl.u.ip4.daddr != inet->inet_daddr) {
1832 peer = inet_getpeer_v4(inet->inet_daddr, 1);
1833 *release_it = true;
1834 } else {
1835 if (!rt->peer)
1836 rt_bind_peer(rt, inet->inet_daddr, 1);
1837 peer = rt->peer;
1838 *release_it = false;
1839 }
1840
1841 return peer;
1842}
1843EXPORT_SYMBOL(tcp_v4_get_peer);
1844
1845void *tcp_v4_tw_get_peer(struct sock *sk)
1846{
1847 const struct inet_timewait_sock *tw = inet_twsk(sk);
1848
1849 return inet_getpeer_v4(tw->tw_daddr, 1);
1850}
1851EXPORT_SYMBOL(tcp_v4_tw_get_peer);
1852
1853static struct timewait_sock_ops tcp_timewait_sock_ops = {
1854 .twsk_obj_size = sizeof(struct tcp_timewait_sock),
1855 .twsk_unique = tcp_twsk_unique,
1856 .twsk_destructor= tcp_twsk_destructor,
1857 .twsk_getpeer = tcp_v4_tw_get_peer,
1858};
1859
1860const struct inet_connection_sock_af_ops ipv4_specific = {
1861 .queue_xmit = ip_queue_xmit,
1862 .send_check = tcp_v4_send_check,
1863 .rebuild_header = inet_sk_rebuild_header,
1864 .conn_request = tcp_v4_conn_request,
1865 .syn_recv_sock = tcp_v4_syn_recv_sock,
1866 .get_peer = tcp_v4_get_peer,
1867 .net_header_len = sizeof(struct iphdr),
1868 .setsockopt = ip_setsockopt,
1869 .getsockopt = ip_getsockopt,
1870 .addr2sockaddr = inet_csk_addr2sockaddr,
1871 .sockaddr_len = sizeof(struct sockaddr_in),
1872 .bind_conflict = inet_csk_bind_conflict,
1873#ifdef CONFIG_COMPAT
1874 .compat_setsockopt = compat_ip_setsockopt,
1875 .compat_getsockopt = compat_ip_getsockopt,
1876#endif
1877};
1878EXPORT_SYMBOL(ipv4_specific);
1879
1880#ifdef CONFIG_TCP_MD5SIG
1881static const struct tcp_sock_af_ops tcp_sock_ipv4_specific = {
1882 .md5_lookup = tcp_v4_md5_lookup,
1883 .calc_md5_hash = tcp_v4_md5_hash_skb,
1884 .md5_parse = tcp_v4_parse_md5_keys,
1885};
1886#endif
1887
1888/* NOTE: A lot of things set to zero explicitly by call to
1889 * sk_alloc() so need not be done here.
1890 */
1891static int tcp_v4_init_sock(struct sock *sk)
1892{
1893 struct inet_connection_sock *icsk = inet_csk(sk);
1894
1895 tcp_init_sock(sk);
1896
1897 icsk->icsk_af_ops = &ipv4_specific;
1898
1899#ifdef CONFIG_TCP_MD5SIG
1900 tcp_sk(sk)->af_specific = &tcp_sock_ipv4_specific;
1901#endif
1902
1903 return 0;
1904}
1905
1906void tcp_v4_destroy_sock(struct sock *sk)
1907{
1908 struct tcp_sock *tp = tcp_sk(sk);
1909
1910 tcp_clear_xmit_timers(sk);
1911
1912 tcp_cleanup_congestion_control(sk);
1913
1914 /* Cleanup up the write buffer. */
1915 tcp_write_queue_purge(sk);
1916
1917 /* Cleans up our, hopefully empty, out_of_order_queue. */
1918 __skb_queue_purge(&tp->out_of_order_queue);
1919
1920#ifdef CONFIG_TCP_MD5SIG
1921 /* Clean up the MD5 key list, if any */
1922 if (tp->md5sig_info) {
1923 tcp_clear_md5_list(sk);
1924 kfree_rcu(tp->md5sig_info, rcu);
1925 tp->md5sig_info = NULL;
1926 }
1927#endif
1928
1929#ifdef CONFIG_NET_DMA
1930 /* Cleans up our sk_async_wait_queue */
1931 __skb_queue_purge(&sk->sk_async_wait_queue);
1932#endif
1933
1934 /* Clean prequeue, it must be empty really */
1935 __skb_queue_purge(&tp->ucopy.prequeue);
1936
1937 /* Clean up a referenced TCP bind bucket. */
1938 if (inet_csk(sk)->icsk_bind_hash)
1939 inet_put_port(sk);
1940
1941 /*
1942 * If sendmsg cached page exists, toss it.
1943 */
1944 if (sk->sk_sndmsg_page) {
1945 __free_page(sk->sk_sndmsg_page);
1946 sk->sk_sndmsg_page = NULL;
1947 }
1948
1949 /* TCP Cookie Transactions */
1950 if (tp->cookie_values != NULL) {
1951 kref_put(&tp->cookie_values->kref,
1952 tcp_cookie_values_release);
1953 tp->cookie_values = NULL;
1954 }
1955
1956 sk_sockets_allocated_dec(sk);
1957 sock_release_memcg(sk);
1958}
1959EXPORT_SYMBOL(tcp_v4_destroy_sock);
1960
1961#ifdef CONFIG_PROC_FS
1962/* Proc filesystem TCP sock list dumping. */
1963
1964static inline struct inet_timewait_sock *tw_head(struct hlist_nulls_head *head)
1965{
1966 return hlist_nulls_empty(head) ? NULL :
1967 list_entry(head->first, struct inet_timewait_sock, tw_node);
1968}
1969
1970static inline struct inet_timewait_sock *tw_next(struct inet_timewait_sock *tw)
1971{
1972 return !is_a_nulls(tw->tw_node.next) ?
1973 hlist_nulls_entry(tw->tw_node.next, typeof(*tw), tw_node) : NULL;
1974}
1975
1976/*
1977 * Get next listener socket follow cur. If cur is NULL, get first socket
1978 * starting from bucket given in st->bucket; when st->bucket is zero the
1979 * very first socket in the hash table is returned.
1980 */
1981static void *listening_get_next(struct seq_file *seq, void *cur)
1982{
1983 struct inet_connection_sock *icsk;
1984 struct hlist_nulls_node *node;
1985 struct sock *sk = cur;
1986 struct inet_listen_hashbucket *ilb;
1987 struct tcp_iter_state *st = seq->private;
1988 struct net *net = seq_file_net(seq);
1989
1990 if (!sk) {
1991 ilb = &tcp_hashinfo.listening_hash[st->bucket];
1992 spin_lock_bh(&ilb->lock);
1993 sk = sk_nulls_head(&ilb->head);
1994 st->offset = 0;
1995 goto get_sk;
1996 }
1997 ilb = &tcp_hashinfo.listening_hash[st->bucket];
1998 ++st->num;
1999 ++st->offset;
2000
2001 if (st->state == TCP_SEQ_STATE_OPENREQ) {
2002 struct request_sock *req = cur;
2003
2004 icsk = inet_csk(st->syn_wait_sk);
2005 req = req->dl_next;
2006 while (1) {
2007 while (req) {
2008 if (req->rsk_ops->family == st->family) {
2009 cur = req;
2010 goto out;
2011 }
2012 req = req->dl_next;
2013 }
2014 if (++st->sbucket >= icsk->icsk_accept_queue.listen_opt->nr_table_entries)
2015 break;
2016get_req:
2017 req = icsk->icsk_accept_queue.listen_opt->syn_table[st->sbucket];
2018 }
2019 sk = sk_nulls_next(st->syn_wait_sk);
2020 st->state = TCP_SEQ_STATE_LISTENING;
2021 read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
2022 } else {
2023 icsk = inet_csk(sk);
2024 read_lock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
2025 if (reqsk_queue_len(&icsk->icsk_accept_queue))
2026 goto start_req;
2027 read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
2028 sk = sk_nulls_next(sk);
2029 }
2030get_sk:
2031 sk_nulls_for_each_from(sk, node) {
2032 if (!net_eq(sock_net(sk), net))
2033 continue;
2034 if (sk->sk_family == st->family) {
2035 cur = sk;
2036 goto out;
2037 }
2038 icsk = inet_csk(sk);
2039 read_lock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
2040 if (reqsk_queue_len(&icsk->icsk_accept_queue)) {
2041start_req:
2042 st->uid = sock_i_uid(sk);
2043 st->syn_wait_sk = sk;
2044 st->state = TCP_SEQ_STATE_OPENREQ;
2045 st->sbucket = 0;
2046 goto get_req;
2047 }
2048 read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
2049 }
2050 spin_unlock_bh(&ilb->lock);
2051 st->offset = 0;
2052 if (++st->bucket < INET_LHTABLE_SIZE) {
2053 ilb = &tcp_hashinfo.listening_hash[st->bucket];
2054 spin_lock_bh(&ilb->lock);
2055 sk = sk_nulls_head(&ilb->head);
2056 goto get_sk;
2057 }
2058 cur = NULL;
2059out:
2060 return cur;
2061}
2062
2063static void *listening_get_idx(struct seq_file *seq, loff_t *pos)
2064{
2065 struct tcp_iter_state *st = seq->private;
2066 void *rc;
2067
2068 st->bucket = 0;
2069 st->offset = 0;
2070 rc = listening_get_next(seq, NULL);
2071
2072 while (rc && *pos) {
2073 rc = listening_get_next(seq, rc);
2074 --*pos;
2075 }
2076 return rc;
2077}
2078
2079static inline bool empty_bucket(struct tcp_iter_state *st)
2080{
2081 return hlist_nulls_empty(&tcp_hashinfo.ehash[st->bucket].chain) &&
2082 hlist_nulls_empty(&tcp_hashinfo.ehash[st->bucket].twchain);
2083}
2084
2085/*
2086 * Get first established socket starting from bucket given in st->bucket.
2087 * If st->bucket is zero, the very first socket in the hash is returned.
2088 */
2089static void *established_get_first(struct seq_file *seq)
2090{
2091 struct tcp_iter_state *st = seq->private;
2092 struct net *net = seq_file_net(seq);
2093 void *rc = NULL;
2094
2095 st->offset = 0;
2096 for (; st->bucket <= tcp_hashinfo.ehash_mask; ++st->bucket) {
2097 struct sock *sk;
2098 struct hlist_nulls_node *node;
2099 struct inet_timewait_sock *tw;
2100 spinlock_t *lock = inet_ehash_lockp(&tcp_hashinfo, st->bucket);
2101
2102 /* Lockless fast path for the common case of empty buckets */
2103 if (empty_bucket(st))
2104 continue;
2105
2106 spin_lock_bh(lock);
2107 sk_nulls_for_each(sk, node, &tcp_hashinfo.ehash[st->bucket].chain) {
2108 if (sk->sk_family != st->family ||
2109 !net_eq(sock_net(sk), net)) {
2110 continue;
2111 }
2112 rc = sk;
2113 goto out;
2114 }
2115 st->state = TCP_SEQ_STATE_TIME_WAIT;
2116 inet_twsk_for_each(tw, node,
2117 &tcp_hashinfo.ehash[st->bucket].twchain) {
2118 if (tw->tw_family != st->family ||
2119 !net_eq(twsk_net(tw), net)) {
2120 continue;
2121 }
2122 rc = tw;
2123 goto out;
2124 }
2125 spin_unlock_bh(lock);
2126 st->state = TCP_SEQ_STATE_ESTABLISHED;
2127 }
2128out:
2129 return rc;
2130}
2131
2132static void *established_get_next(struct seq_file *seq, void *cur)
2133{
2134 struct sock *sk = cur;
2135 struct inet_timewait_sock *tw;
2136 struct hlist_nulls_node *node;
2137 struct tcp_iter_state *st = seq->private;
2138 struct net *net = seq_file_net(seq);
2139
2140 ++st->num;
2141 ++st->offset;
2142
2143 if (st->state == TCP_SEQ_STATE_TIME_WAIT) {
2144 tw = cur;
2145 tw = tw_next(tw);
2146get_tw:
2147 while (tw && (tw->tw_family != st->family || !net_eq(twsk_net(tw), net))) {
2148 tw = tw_next(tw);
2149 }
2150 if (tw) {
2151 cur = tw;
2152 goto out;
2153 }
2154 spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
2155 st->state = TCP_SEQ_STATE_ESTABLISHED;
2156
2157 /* Look for next non empty bucket */
2158 st->offset = 0;
2159 while (++st->bucket <= tcp_hashinfo.ehash_mask &&
2160 empty_bucket(st))
2161 ;
2162 if (st->bucket > tcp_hashinfo.ehash_mask)
2163 return NULL;
2164
2165 spin_lock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
2166 sk = sk_nulls_head(&tcp_hashinfo.ehash[st->bucket].chain);
2167 } else
2168 sk = sk_nulls_next(sk);
2169
2170 sk_nulls_for_each_from(sk, node) {
2171 if (sk->sk_family == st->family && net_eq(sock_net(sk), net))
2172 goto found;
2173 }
2174
2175 st->state = TCP_SEQ_STATE_TIME_WAIT;
2176 tw = tw_head(&tcp_hashinfo.ehash[st->bucket].twchain);
2177 goto get_tw;
2178found:
2179 cur = sk;
2180out:
2181 return cur;
2182}
2183
2184static void *established_get_idx(struct seq_file *seq, loff_t pos)
2185{
2186 struct tcp_iter_state *st = seq->private;
2187 void *rc;
2188
2189 st->bucket = 0;
2190 rc = established_get_first(seq);
2191
2192 while (rc && pos) {
2193 rc = established_get_next(seq, rc);
2194 --pos;
2195 }
2196 return rc;
2197}
2198
2199static void *tcp_get_idx(struct seq_file *seq, loff_t pos)
2200{
2201 void *rc;
2202 struct tcp_iter_state *st = seq->private;
2203
2204 st->state = TCP_SEQ_STATE_LISTENING;
2205 rc = listening_get_idx(seq, &pos);
2206
2207 if (!rc) {
2208 st->state = TCP_SEQ_STATE_ESTABLISHED;
2209 rc = established_get_idx(seq, pos);
2210 }
2211
2212 return rc;
2213}
2214
2215static void *tcp_seek_last_pos(struct seq_file *seq)
2216{
2217 struct tcp_iter_state *st = seq->private;
2218 int offset = st->offset;
2219 int orig_num = st->num;
2220 void *rc = NULL;
2221
2222 switch (st->state) {
2223 case TCP_SEQ_STATE_OPENREQ:
2224 case TCP_SEQ_STATE_LISTENING:
2225 if (st->bucket >= INET_LHTABLE_SIZE)
2226 break;
2227 st->state = TCP_SEQ_STATE_LISTENING;
2228 rc = listening_get_next(seq, NULL);
2229 while (offset-- && rc)
2230 rc = listening_get_next(seq, rc);
2231 if (rc)
2232 break;
2233 st->bucket = 0;
2234 /* Fallthrough */
2235 case TCP_SEQ_STATE_ESTABLISHED:
2236 case TCP_SEQ_STATE_TIME_WAIT:
2237 st->state = TCP_SEQ_STATE_ESTABLISHED;
2238 if (st->bucket > tcp_hashinfo.ehash_mask)
2239 break;
2240 rc = established_get_first(seq);
2241 while (offset-- && rc)
2242 rc = established_get_next(seq, rc);
2243 }
2244
2245 st->num = orig_num;
2246
2247 return rc;
2248}
2249
2250static void *tcp_seq_start(struct seq_file *seq, loff_t *pos)
2251{
2252 struct tcp_iter_state *st = seq->private;
2253 void *rc;
2254
2255 if (*pos && *pos == st->last_pos) {
2256 rc = tcp_seek_last_pos(seq);
2257 if (rc)
2258 goto out;
2259 }
2260
2261 st->state = TCP_SEQ_STATE_LISTENING;
2262 st->num = 0;
2263 st->bucket = 0;
2264 st->offset = 0;
2265 rc = *pos ? tcp_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
2266
2267out:
2268 st->last_pos = *pos;
2269 return rc;
2270}
2271
2272static void *tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2273{
2274 struct tcp_iter_state *st = seq->private;
2275 void *rc = NULL;
2276
2277 if (v == SEQ_START_TOKEN) {
2278 rc = tcp_get_idx(seq, 0);
2279 goto out;
2280 }
2281
2282 switch (st->state) {
2283 case TCP_SEQ_STATE_OPENREQ:
2284 case TCP_SEQ_STATE_LISTENING:
2285 rc = listening_get_next(seq, v);
2286 if (!rc) {
2287 st->state = TCP_SEQ_STATE_ESTABLISHED;
2288 st->bucket = 0;
2289 st->offset = 0;
2290 rc = established_get_first(seq);
2291 }
2292 break;
2293 case TCP_SEQ_STATE_ESTABLISHED:
2294 case TCP_SEQ_STATE_TIME_WAIT:
2295 rc = established_get_next(seq, v);
2296 break;
2297 }
2298out:
2299 ++*pos;
2300 st->last_pos = *pos;
2301 return rc;
2302}
2303
2304static void tcp_seq_stop(struct seq_file *seq, void *v)
2305{
2306 struct tcp_iter_state *st = seq->private;
2307
2308 switch (st->state) {
2309 case TCP_SEQ_STATE_OPENREQ:
2310 if (v) {
2311 struct inet_connection_sock *icsk = inet_csk(st->syn_wait_sk);
2312 read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
2313 }
2314 case TCP_SEQ_STATE_LISTENING:
2315 if (v != SEQ_START_TOKEN)
2316 spin_unlock_bh(&tcp_hashinfo.listening_hash[st->bucket].lock);
2317 break;
2318 case TCP_SEQ_STATE_TIME_WAIT:
2319 case TCP_SEQ_STATE_ESTABLISHED:
2320 if (v)
2321 spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
2322 break;
2323 }
2324}
2325
2326int tcp_seq_open(struct inode *inode, struct file *file)
2327{
2328 struct tcp_seq_afinfo *afinfo = PDE(inode)->data;
2329 struct tcp_iter_state *s;
2330 int err;
2331
2332 err = seq_open_net(inode, file, &afinfo->seq_ops,
2333 sizeof(struct tcp_iter_state));
2334 if (err < 0)
2335 return err;
2336
2337 s = ((struct seq_file *)file->private_data)->private;
2338 s->family = afinfo->family;
2339 s->last_pos = 0;
2340 return 0;
2341}
2342EXPORT_SYMBOL(tcp_seq_open);
2343
2344int tcp_proc_register(struct net *net, struct tcp_seq_afinfo *afinfo)
2345{
2346 int rc = 0;
2347 struct proc_dir_entry *p;
2348
2349 afinfo->seq_ops.start = tcp_seq_start;
2350 afinfo->seq_ops.next = tcp_seq_next;
2351 afinfo->seq_ops.stop = tcp_seq_stop;
2352
2353 p = proc_create_data(afinfo->name, S_IRUGO, net->proc_net,
2354 afinfo->seq_fops, afinfo);
2355 if (!p)
2356 rc = -ENOMEM;
2357 return rc;
2358}
2359EXPORT_SYMBOL(tcp_proc_register);
2360
2361void tcp_proc_unregister(struct net *net, struct tcp_seq_afinfo *afinfo)
2362{
2363 proc_net_remove(net, afinfo->name);
2364}
2365EXPORT_SYMBOL(tcp_proc_unregister);
2366
2367static void get_openreq4(const struct sock *sk, const struct request_sock *req,
2368 struct seq_file *f, int i, int uid, int *len)
2369{
2370 const struct inet_request_sock *ireq = inet_rsk(req);
2371 int ttd = req->expires - jiffies;
2372
2373 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2374 " %02X %08X:%08X %02X:%08lX %08X %5d %8d %u %d %pK%n",
2375 i,
2376 ireq->loc_addr,
2377 ntohs(inet_sk(sk)->inet_sport),
2378 ireq->rmt_addr,
2379 ntohs(ireq->rmt_port),
2380 TCP_SYN_RECV,
2381 0, 0, /* could print option size, but that is af dependent. */
2382 1, /* timers active (only the expire timer) */
2383 jiffies_to_clock_t(ttd),
2384 req->retrans,
2385 uid,
2386 0, /* non standard timer */
2387 0, /* open_requests have no inode */
2388 atomic_read(&sk->sk_refcnt),
2389 req,
2390 len);
2391}
2392
2393static void get_tcp4_sock(struct sock *sk, struct seq_file *f, int i, int *len)
2394{
2395 int timer_active;
2396 unsigned long timer_expires;
2397 const struct tcp_sock *tp = tcp_sk(sk);
2398 const struct inet_connection_sock *icsk = inet_csk(sk);
2399 const struct inet_sock *inet = inet_sk(sk);
2400 __be32 dest = inet->inet_daddr;
2401 __be32 src = inet->inet_rcv_saddr;
2402 __u16 destp = ntohs(inet->inet_dport);
2403 __u16 srcp = ntohs(inet->inet_sport);
2404 int rx_queue;
2405
2406 if (icsk->icsk_pending == ICSK_TIME_RETRANS) {
2407 timer_active = 1;
2408 timer_expires = icsk->icsk_timeout;
2409 } else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
2410 timer_active = 4;
2411 timer_expires = icsk->icsk_timeout;
2412 } else if (timer_pending(&sk->sk_timer)) {
2413 timer_active = 2;
2414 timer_expires = sk->sk_timer.expires;
2415 } else {
2416 timer_active = 0;
2417 timer_expires = jiffies;
2418 }
2419
2420 if (sk->sk_state == TCP_LISTEN)
2421 rx_queue = sk->sk_ack_backlog;
2422 else
2423 /*
2424 * because we dont lock socket, we might find a transient negative value
2425 */
2426 rx_queue = max_t(int, tp->rcv_nxt - tp->copied_seq, 0);
2427
2428 seq_printf(f, "%4d: %08X:%04X %08X:%04X %02X %08X:%08X %02X:%08lX "
2429 "%08X %5d %8d %lu %d %pK %lu %lu %u %u %d%n",
2430 i, src, srcp, dest, destp, sk->sk_state,
2431 tp->write_seq - tp->snd_una,
2432 rx_queue,
2433 timer_active,
2434 jiffies_to_clock_t(timer_expires - jiffies),
2435 icsk->icsk_retransmits,
2436 sock_i_uid(sk),
2437 icsk->icsk_probes_out,
2438 sock_i_ino(sk),
2439 atomic_read(&sk->sk_refcnt), sk,
2440 jiffies_to_clock_t(icsk->icsk_rto),
2441 jiffies_to_clock_t(icsk->icsk_ack.ato),
2442 (icsk->icsk_ack.quick << 1) | icsk->icsk_ack.pingpong,
2443 tp->snd_cwnd,
2444 tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh,
2445 len);
2446}
2447
2448static void get_timewait4_sock(const struct inet_timewait_sock *tw,
2449 struct seq_file *f, int i, int *len)
2450{
2451 __be32 dest, src;
2452 __u16 destp, srcp;
2453 int ttd = tw->tw_ttd - jiffies;
2454
2455 if (ttd < 0)
2456 ttd = 0;
2457
2458 dest = tw->tw_daddr;
2459 src = tw->tw_rcv_saddr;
2460 destp = ntohs(tw->tw_dport);
2461 srcp = ntohs(tw->tw_sport);
2462
2463 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2464 " %02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK%n",
2465 i, src, srcp, dest, destp, tw->tw_substate, 0, 0,
2466 3, jiffies_to_clock_t(ttd), 0, 0, 0, 0,
2467 atomic_read(&tw->tw_refcnt), tw, len);
2468}
2469
2470#define TMPSZ 150
2471
2472static int tcp4_seq_show(struct seq_file *seq, void *v)
2473{
2474 struct tcp_iter_state *st;
2475 int len;
2476
2477 if (v == SEQ_START_TOKEN) {
2478 seq_printf(seq, "%-*s\n", TMPSZ - 1,
2479 " sl local_address rem_address st tx_queue "
2480 "rx_queue tr tm->when retrnsmt uid timeout "
2481 "inode");
2482 goto out;
2483 }
2484 st = seq->private;
2485
2486 switch (st->state) {
2487 case TCP_SEQ_STATE_LISTENING:
2488 case TCP_SEQ_STATE_ESTABLISHED:
2489 get_tcp4_sock(v, seq, st->num, &len);
2490 break;
2491 case TCP_SEQ_STATE_OPENREQ:
2492 get_openreq4(st->syn_wait_sk, v, seq, st->num, st->uid, &len);
2493 break;
2494 case TCP_SEQ_STATE_TIME_WAIT:
2495 get_timewait4_sock(v, seq, st->num, &len);
2496 break;
2497 }
2498 seq_printf(seq, "%*s\n", TMPSZ - 1 - len, "");
2499out:
2500 return 0;
2501}
2502
2503static const struct file_operations tcp_afinfo_seq_fops = {
2504 .owner = THIS_MODULE,
2505 .open = tcp_seq_open,
2506 .read = seq_read,
2507 .llseek = seq_lseek,
2508 .release = seq_release_net
2509};
2510
2511static struct tcp_seq_afinfo tcp4_seq_afinfo = {
2512 .name = "tcp",
2513 .family = AF_INET,
2514 .seq_fops = &tcp_afinfo_seq_fops,
2515 .seq_ops = {
2516 .show = tcp4_seq_show,
2517 },
2518};
2519
2520static int __net_init tcp4_proc_init_net(struct net *net)
2521{
2522 return tcp_proc_register(net, &tcp4_seq_afinfo);
2523}
2524
2525static void __net_exit tcp4_proc_exit_net(struct net *net)
2526{
2527 tcp_proc_unregister(net, &tcp4_seq_afinfo);
2528}
2529
2530static struct pernet_operations tcp4_net_ops = {
2531 .init = tcp4_proc_init_net,
2532 .exit = tcp4_proc_exit_net,
2533};
2534
2535int __init tcp4_proc_init(void)
2536{
2537 return register_pernet_subsys(&tcp4_net_ops);
2538}
2539
2540void tcp4_proc_exit(void)
2541{
2542 unregister_pernet_subsys(&tcp4_net_ops);
2543}
2544#endif /* CONFIG_PROC_FS */
2545
2546struct sk_buff **tcp4_gro_receive(struct sk_buff **head, struct sk_buff *skb)
2547{
2548 const struct iphdr *iph = skb_gro_network_header(skb);
2549
2550 switch (skb->ip_summed) {
2551 case CHECKSUM_COMPLETE:
2552 if (!tcp_v4_check(skb_gro_len(skb), iph->saddr, iph->daddr,
2553 skb->csum)) {
2554 skb->ip_summed = CHECKSUM_UNNECESSARY;
2555 break;
2556 }
2557
2558 /* fall through */
2559 case CHECKSUM_NONE:
2560 NAPI_GRO_CB(skb)->flush = 1;
2561 return NULL;
2562 }
2563
2564 return tcp_gro_receive(head, skb);
2565}
2566
2567int tcp4_gro_complete(struct sk_buff *skb)
2568{
2569 const struct iphdr *iph = ip_hdr(skb);
2570 struct tcphdr *th = tcp_hdr(skb);
2571
2572 th->check = ~tcp_v4_check(skb->len - skb_transport_offset(skb),
2573 iph->saddr, iph->daddr, 0);
2574 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
2575
2576 return tcp_gro_complete(skb);
2577}
2578
2579struct proto tcp_prot = {
2580 .name = "TCP",
2581 .owner = THIS_MODULE,
2582 .close = tcp_close,
2583 .connect = tcp_v4_connect,
2584 .disconnect = tcp_disconnect,
2585 .accept = inet_csk_accept,
2586 .ioctl = tcp_ioctl,
2587 .init = tcp_v4_init_sock,
2588 .destroy = tcp_v4_destroy_sock,
2589 .shutdown = tcp_shutdown,
2590 .setsockopt = tcp_setsockopt,
2591 .getsockopt = tcp_getsockopt,
2592 .recvmsg = tcp_recvmsg,
2593 .sendmsg = tcp_sendmsg,
2594 .sendpage = tcp_sendpage,
2595 .backlog_rcv = tcp_v4_do_rcv,
2596 .hash = inet_hash,
2597 .unhash = inet_unhash,
2598 .get_port = inet_csk_get_port,
2599 .enter_memory_pressure = tcp_enter_memory_pressure,
2600 .sockets_allocated = &tcp_sockets_allocated,
2601 .orphan_count = &tcp_orphan_count,
2602 .memory_allocated = &tcp_memory_allocated,
2603 .memory_pressure = &tcp_memory_pressure,
2604 .sysctl_wmem = sysctl_tcp_wmem,
2605 .sysctl_rmem = sysctl_tcp_rmem,
2606 .max_header = MAX_TCP_HEADER,
2607 .obj_size = sizeof(struct tcp_sock),
2608 .slab_flags = SLAB_DESTROY_BY_RCU,
2609 .twsk_prot = &tcp_timewait_sock_ops,
2610 .rsk_prot = &tcp_request_sock_ops,
2611 .h.hashinfo = &tcp_hashinfo,
2612 .no_autobind = true,
2613#ifdef CONFIG_COMPAT
2614 .compat_setsockopt = compat_tcp_setsockopt,
2615 .compat_getsockopt = compat_tcp_getsockopt,
2616#endif
2617#ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM
2618 .init_cgroup = tcp_init_cgroup,
2619 .destroy_cgroup = tcp_destroy_cgroup,
2620 .proto_cgroup = tcp_proto_cgroup,
2621#endif
2622};
2623EXPORT_SYMBOL(tcp_prot);
2624
2625static int __net_init tcp_sk_init(struct net *net)
2626{
2627 return inet_ctl_sock_create(&net->ipv4.tcp_sock,
2628 PF_INET, SOCK_RAW, IPPROTO_TCP, net);
2629}
2630
2631static void __net_exit tcp_sk_exit(struct net *net)
2632{
2633 inet_ctl_sock_destroy(net->ipv4.tcp_sock);
2634}
2635
2636static void __net_exit tcp_sk_exit_batch(struct list_head *net_exit_list)
2637{
2638 inet_twsk_purge(&tcp_hashinfo, &tcp_death_row, AF_INET);
2639}
2640
2641static struct pernet_operations __net_initdata tcp_sk_ops = {
2642 .init = tcp_sk_init,
2643 .exit = tcp_sk_exit,
2644 .exit_batch = tcp_sk_exit_batch,
2645};
2646
2647void __init tcp_v4_init(void)
2648{
2649 inet_hashinfo_init(&tcp_hashinfo);
2650 if (register_pernet_subsys(&tcp_sk_ops))
2651 panic("Failed to create the TCP control socket.\n");
2652}