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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * INET An implementation of the TCP/IP protocol suite for the LINUX
4 * operating system. INET is implemented using the BSD Socket
5 * interface as the means of communication with the user level.
6 *
7 * Implementation of the Transmission Control Protocol(TCP).
8 *
9 * IPv4 specific functions
10 *
11 * code split from:
12 * linux/ipv4/tcp.c
13 * linux/ipv4/tcp_input.c
14 * linux/ipv4/tcp_output.c
15 *
16 * See tcp.c for author information
17 */
18
19/*
20 * Changes:
21 * David S. Miller : New socket lookup architecture.
22 * This code is dedicated to John Dyson.
23 * David S. Miller : Change semantics of established hash,
24 * half is devoted to TIME_WAIT sockets
25 * and the rest go in the other half.
26 * Andi Kleen : Add support for syncookies and fixed
27 * some bugs: ip options weren't passed to
28 * the TCP layer, missed a check for an
29 * ACK bit.
30 * Andi Kleen : Implemented fast path mtu discovery.
31 * Fixed many serious bugs in the
32 * request_sock handling and moved
33 * most of it into the af independent code.
34 * Added tail drop and some other bugfixes.
35 * Added new listen semantics.
36 * Mike McLagan : Routing by source
37 * Juan Jose Ciarlante: ip_dynaddr bits
38 * Andi Kleen: various fixes.
39 * Vitaly E. Lavrov : Transparent proxy revived after year
40 * coma.
41 * Andi Kleen : Fix new listen.
42 * Andi Kleen : Fix accept error reporting.
43 * YOSHIFUJI Hideaki @USAGI and: Support IPV6_V6ONLY socket option, which
44 * Alexey Kuznetsov allow both IPv4 and IPv6 sockets to bind
45 * a single port at the same time.
46 */
47
48#define pr_fmt(fmt) "TCP: " fmt
49
50#include <linux/bottom_half.h>
51#include <linux/types.h>
52#include <linux/fcntl.h>
53#include <linux/module.h>
54#include <linux/random.h>
55#include <linux/cache.h>
56#include <linux/jhash.h>
57#include <linux/init.h>
58#include <linux/times.h>
59#include <linux/slab.h>
60
61#include <net/net_namespace.h>
62#include <net/icmp.h>
63#include <net/inet_hashtables.h>
64#include <net/tcp.h>
65#include <net/transp_v6.h>
66#include <net/ipv6.h>
67#include <net/inet_common.h>
68#include <net/timewait_sock.h>
69#include <net/xfrm.h>
70#include <net/secure_seq.h>
71#include <net/busy_poll.h>
72
73#include <linux/inet.h>
74#include <linux/ipv6.h>
75#include <linux/stddef.h>
76#include <linux/proc_fs.h>
77#include <linux/seq_file.h>
78#include <linux/inetdevice.h>
79#include <linux/btf_ids.h>
80
81#include <crypto/hash.h>
82#include <linux/scatterlist.h>
83
84#include <trace/events/tcp.h>
85
86#ifdef CONFIG_TCP_MD5SIG
87static int tcp_v4_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key,
88 __be32 daddr, __be32 saddr, const struct tcphdr *th);
89#endif
90
91struct inet_hashinfo tcp_hashinfo;
92EXPORT_SYMBOL(tcp_hashinfo);
93
94static u32 tcp_v4_init_seq(const struct sk_buff *skb)
95{
96 return secure_tcp_seq(ip_hdr(skb)->daddr,
97 ip_hdr(skb)->saddr,
98 tcp_hdr(skb)->dest,
99 tcp_hdr(skb)->source);
100}
101
102static u32 tcp_v4_init_ts_off(const struct net *net, const struct sk_buff *skb)
103{
104 return secure_tcp_ts_off(net, ip_hdr(skb)->daddr, ip_hdr(skb)->saddr);
105}
106
107int tcp_twsk_unique(struct sock *sk, struct sock *sktw, void *twp)
108{
109 const struct inet_timewait_sock *tw = inet_twsk(sktw);
110 const struct tcp_timewait_sock *tcptw = tcp_twsk(sktw);
111 struct tcp_sock *tp = tcp_sk(sk);
112 int reuse = sock_net(sk)->ipv4.sysctl_tcp_tw_reuse;
113
114 if (reuse == 2) {
115 /* Still does not detect *everything* that goes through
116 * lo, since we require a loopback src or dst address
117 * or direct binding to 'lo' interface.
118 */
119 bool loopback = false;
120 if (tw->tw_bound_dev_if == LOOPBACK_IFINDEX)
121 loopback = true;
122#if IS_ENABLED(CONFIG_IPV6)
123 if (tw->tw_family == AF_INET6) {
124 if (ipv6_addr_loopback(&tw->tw_v6_daddr) ||
125 ipv6_addr_v4mapped_loopback(&tw->tw_v6_daddr) ||
126 ipv6_addr_loopback(&tw->tw_v6_rcv_saddr) ||
127 ipv6_addr_v4mapped_loopback(&tw->tw_v6_rcv_saddr))
128 loopback = true;
129 } else
130#endif
131 {
132 if (ipv4_is_loopback(tw->tw_daddr) ||
133 ipv4_is_loopback(tw->tw_rcv_saddr))
134 loopback = true;
135 }
136 if (!loopback)
137 reuse = 0;
138 }
139
140 /* With PAWS, it is safe from the viewpoint
141 of data integrity. Even without PAWS it is safe provided sequence
142 spaces do not overlap i.e. at data rates <= 80Mbit/sec.
143
144 Actually, the idea is close to VJ's one, only timestamp cache is
145 held not per host, but per port pair and TW bucket is used as state
146 holder.
147
148 If TW bucket has been already destroyed we fall back to VJ's scheme
149 and use initial timestamp retrieved from peer table.
150 */
151 if (tcptw->tw_ts_recent_stamp &&
152 (!twp || (reuse && time_after32(ktime_get_seconds(),
153 tcptw->tw_ts_recent_stamp)))) {
154 /* In case of repair and re-using TIME-WAIT sockets we still
155 * want to be sure that it is safe as above but honor the
156 * sequence numbers and time stamps set as part of the repair
157 * process.
158 *
159 * Without this check re-using a TIME-WAIT socket with TCP
160 * repair would accumulate a -1 on the repair assigned
161 * sequence number. The first time it is reused the sequence
162 * is -1, the second time -2, etc. This fixes that issue
163 * without appearing to create any others.
164 */
165 if (likely(!tp->repair)) {
166 u32 seq = tcptw->tw_snd_nxt + 65535 + 2;
167
168 if (!seq)
169 seq = 1;
170 WRITE_ONCE(tp->write_seq, seq);
171 tp->rx_opt.ts_recent = tcptw->tw_ts_recent;
172 tp->rx_opt.ts_recent_stamp = tcptw->tw_ts_recent_stamp;
173 }
174 sock_hold(sktw);
175 return 1;
176 }
177
178 return 0;
179}
180EXPORT_SYMBOL_GPL(tcp_twsk_unique);
181
182static int tcp_v4_pre_connect(struct sock *sk, struct sockaddr *uaddr,
183 int addr_len)
184{
185 /* This check is replicated from tcp_v4_connect() and intended to
186 * prevent BPF program called below from accessing bytes that are out
187 * of the bound specified by user in addr_len.
188 */
189 if (addr_len < sizeof(struct sockaddr_in))
190 return -EINVAL;
191
192 sock_owned_by_me(sk);
193
194 return BPF_CGROUP_RUN_PROG_INET4_CONNECT(sk, uaddr);
195}
196
197/* This will initiate an outgoing connection. */
198int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
199{
200 struct sockaddr_in *usin = (struct sockaddr_in *)uaddr;
201 struct inet_sock *inet = inet_sk(sk);
202 struct tcp_sock *tp = tcp_sk(sk);
203 __be16 orig_sport, orig_dport;
204 __be32 daddr, nexthop;
205 struct flowi4 *fl4;
206 struct rtable *rt;
207 int err;
208 struct ip_options_rcu *inet_opt;
209 struct inet_timewait_death_row *tcp_death_row = &sock_net(sk)->ipv4.tcp_death_row;
210
211 if (addr_len < sizeof(struct sockaddr_in))
212 return -EINVAL;
213
214 if (usin->sin_family != AF_INET)
215 return -EAFNOSUPPORT;
216
217 nexthop = daddr = usin->sin_addr.s_addr;
218 inet_opt = rcu_dereference_protected(inet->inet_opt,
219 lockdep_sock_is_held(sk));
220 if (inet_opt && inet_opt->opt.srr) {
221 if (!daddr)
222 return -EINVAL;
223 nexthop = inet_opt->opt.faddr;
224 }
225
226 orig_sport = inet->inet_sport;
227 orig_dport = usin->sin_port;
228 fl4 = &inet->cork.fl.u.ip4;
229 rt = ip_route_connect(fl4, nexthop, inet->inet_saddr,
230 RT_CONN_FLAGS(sk), sk->sk_bound_dev_if,
231 IPPROTO_TCP,
232 orig_sport, orig_dport, sk);
233 if (IS_ERR(rt)) {
234 err = PTR_ERR(rt);
235 if (err == -ENETUNREACH)
236 IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTNOROUTES);
237 return err;
238 }
239
240 if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) {
241 ip_rt_put(rt);
242 return -ENETUNREACH;
243 }
244
245 if (!inet_opt || !inet_opt->opt.srr)
246 daddr = fl4->daddr;
247
248 if (!inet->inet_saddr)
249 inet->inet_saddr = fl4->saddr;
250 sk_rcv_saddr_set(sk, inet->inet_saddr);
251
252 if (tp->rx_opt.ts_recent_stamp && inet->inet_daddr != daddr) {
253 /* Reset inherited state */
254 tp->rx_opt.ts_recent = 0;
255 tp->rx_opt.ts_recent_stamp = 0;
256 if (likely(!tp->repair))
257 WRITE_ONCE(tp->write_seq, 0);
258 }
259
260 inet->inet_dport = usin->sin_port;
261 sk_daddr_set(sk, daddr);
262
263 inet_csk(sk)->icsk_ext_hdr_len = 0;
264 if (inet_opt)
265 inet_csk(sk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
266
267 tp->rx_opt.mss_clamp = TCP_MSS_DEFAULT;
268
269 /* Socket identity is still unknown (sport may be zero).
270 * However we set state to SYN-SENT and not releasing socket
271 * lock select source port, enter ourselves into the hash tables and
272 * complete initialization after this.
273 */
274 tcp_set_state(sk, TCP_SYN_SENT);
275 err = inet_hash_connect(tcp_death_row, sk);
276 if (err)
277 goto failure;
278
279 sk_set_txhash(sk);
280
281 rt = ip_route_newports(fl4, rt, orig_sport, orig_dport,
282 inet->inet_sport, inet->inet_dport, sk);
283 if (IS_ERR(rt)) {
284 err = PTR_ERR(rt);
285 rt = NULL;
286 goto failure;
287 }
288 /* OK, now commit destination to socket. */
289 sk->sk_gso_type = SKB_GSO_TCPV4;
290 sk_setup_caps(sk, &rt->dst);
291 rt = NULL;
292
293 if (likely(!tp->repair)) {
294 if (!tp->write_seq)
295 WRITE_ONCE(tp->write_seq,
296 secure_tcp_seq(inet->inet_saddr,
297 inet->inet_daddr,
298 inet->inet_sport,
299 usin->sin_port));
300 tp->tsoffset = secure_tcp_ts_off(sock_net(sk),
301 inet->inet_saddr,
302 inet->inet_daddr);
303 }
304
305 inet->inet_id = prandom_u32();
306
307 if (tcp_fastopen_defer_connect(sk, &err))
308 return err;
309 if (err)
310 goto failure;
311
312 err = tcp_connect(sk);
313
314 if (err)
315 goto failure;
316
317 return 0;
318
319failure:
320 /*
321 * This unhashes the socket and releases the local port,
322 * if necessary.
323 */
324 tcp_set_state(sk, TCP_CLOSE);
325 ip_rt_put(rt);
326 sk->sk_route_caps = 0;
327 inet->inet_dport = 0;
328 return err;
329}
330EXPORT_SYMBOL(tcp_v4_connect);
331
332/*
333 * This routine reacts to ICMP_FRAG_NEEDED mtu indications as defined in RFC1191.
334 * It can be called through tcp_release_cb() if socket was owned by user
335 * at the time tcp_v4_err() was called to handle ICMP message.
336 */
337void tcp_v4_mtu_reduced(struct sock *sk)
338{
339 struct inet_sock *inet = inet_sk(sk);
340 struct dst_entry *dst;
341 u32 mtu;
342
343 if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE))
344 return;
345 mtu = READ_ONCE(tcp_sk(sk)->mtu_info);
346 dst = inet_csk_update_pmtu(sk, mtu);
347 if (!dst)
348 return;
349
350 /* Something is about to be wrong... Remember soft error
351 * for the case, if this connection will not able to recover.
352 */
353 if (mtu < dst_mtu(dst) && ip_dont_fragment(sk, dst))
354 sk->sk_err_soft = EMSGSIZE;
355
356 mtu = dst_mtu(dst);
357
358 if (inet->pmtudisc != IP_PMTUDISC_DONT &&
359 ip_sk_accept_pmtu(sk) &&
360 inet_csk(sk)->icsk_pmtu_cookie > mtu) {
361 tcp_sync_mss(sk, mtu);
362
363 /* Resend the TCP packet because it's
364 * clear that the old packet has been
365 * dropped. This is the new "fast" path mtu
366 * discovery.
367 */
368 tcp_simple_retransmit(sk);
369 } /* else let the usual retransmit timer handle it */
370}
371EXPORT_SYMBOL(tcp_v4_mtu_reduced);
372
373static void do_redirect(struct sk_buff *skb, struct sock *sk)
374{
375 struct dst_entry *dst = __sk_dst_check(sk, 0);
376
377 if (dst)
378 dst->ops->redirect(dst, sk, skb);
379}
380
381
382/* handle ICMP messages on TCP_NEW_SYN_RECV request sockets */
383void tcp_req_err(struct sock *sk, u32 seq, bool abort)
384{
385 struct request_sock *req = inet_reqsk(sk);
386 struct net *net = sock_net(sk);
387
388 /* ICMPs are not backlogged, hence we cannot get
389 * an established socket here.
390 */
391 if (seq != tcp_rsk(req)->snt_isn) {
392 __NET_INC_STATS(net, LINUX_MIB_OUTOFWINDOWICMPS);
393 } else if (abort) {
394 /*
395 * Still in SYN_RECV, just remove it silently.
396 * There is no good way to pass the error to the newly
397 * created socket, and POSIX does not want network
398 * errors returned from accept().
399 */
400 inet_csk_reqsk_queue_drop(req->rsk_listener, req);
401 tcp_listendrop(req->rsk_listener);
402 }
403 reqsk_put(req);
404}
405EXPORT_SYMBOL(tcp_req_err);
406
407/* TCP-LD (RFC 6069) logic */
408void tcp_ld_RTO_revert(struct sock *sk, u32 seq)
409{
410 struct inet_connection_sock *icsk = inet_csk(sk);
411 struct tcp_sock *tp = tcp_sk(sk);
412 struct sk_buff *skb;
413 s32 remaining;
414 u32 delta_us;
415
416 if (sock_owned_by_user(sk))
417 return;
418
419 if (seq != tp->snd_una || !icsk->icsk_retransmits ||
420 !icsk->icsk_backoff)
421 return;
422
423 skb = tcp_rtx_queue_head(sk);
424 if (WARN_ON_ONCE(!skb))
425 return;
426
427 icsk->icsk_backoff--;
428 icsk->icsk_rto = tp->srtt_us ? __tcp_set_rto(tp) : TCP_TIMEOUT_INIT;
429 icsk->icsk_rto = inet_csk_rto_backoff(icsk, TCP_RTO_MAX);
430
431 tcp_mstamp_refresh(tp);
432 delta_us = (u32)(tp->tcp_mstamp - tcp_skb_timestamp_us(skb));
433 remaining = icsk->icsk_rto - usecs_to_jiffies(delta_us);
434
435 if (remaining > 0) {
436 inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
437 remaining, TCP_RTO_MAX);
438 } else {
439 /* RTO revert clocked out retransmission.
440 * Will retransmit now.
441 */
442 tcp_retransmit_timer(sk);
443 }
444}
445EXPORT_SYMBOL(tcp_ld_RTO_revert);
446
447/*
448 * This routine is called by the ICMP module when it gets some
449 * sort of error condition. If err < 0 then the socket should
450 * be closed and the error returned to the user. If err > 0
451 * it's just the icmp type << 8 | icmp code. After adjustment
452 * header points to the first 8 bytes of the tcp header. We need
453 * to find the appropriate port.
454 *
455 * The locking strategy used here is very "optimistic". When
456 * someone else accesses the socket the ICMP is just dropped
457 * and for some paths there is no check at all.
458 * A more general error queue to queue errors for later handling
459 * is probably better.
460 *
461 */
462
463int tcp_v4_err(struct sk_buff *skb, u32 info)
464{
465 const struct iphdr *iph = (const struct iphdr *)skb->data;
466 struct tcphdr *th = (struct tcphdr *)(skb->data + (iph->ihl << 2));
467 struct tcp_sock *tp;
468 struct inet_sock *inet;
469 const int type = icmp_hdr(skb)->type;
470 const int code = icmp_hdr(skb)->code;
471 struct sock *sk;
472 struct request_sock *fastopen;
473 u32 seq, snd_una;
474 int err;
475 struct net *net = dev_net(skb->dev);
476
477 sk = __inet_lookup_established(net, &tcp_hashinfo, iph->daddr,
478 th->dest, iph->saddr, ntohs(th->source),
479 inet_iif(skb), 0);
480 if (!sk) {
481 __ICMP_INC_STATS(net, ICMP_MIB_INERRORS);
482 return -ENOENT;
483 }
484 if (sk->sk_state == TCP_TIME_WAIT) {
485 inet_twsk_put(inet_twsk(sk));
486 return 0;
487 }
488 seq = ntohl(th->seq);
489 if (sk->sk_state == TCP_NEW_SYN_RECV) {
490 tcp_req_err(sk, seq, type == ICMP_PARAMETERPROB ||
491 type == ICMP_TIME_EXCEEDED ||
492 (type == ICMP_DEST_UNREACH &&
493 (code == ICMP_NET_UNREACH ||
494 code == ICMP_HOST_UNREACH)));
495 return 0;
496 }
497
498 bh_lock_sock(sk);
499 /* If too many ICMPs get dropped on busy
500 * servers this needs to be solved differently.
501 * We do take care of PMTU discovery (RFC1191) special case :
502 * we can receive locally generated ICMP messages while socket is held.
503 */
504 if (sock_owned_by_user(sk)) {
505 if (!(type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED))
506 __NET_INC_STATS(net, LINUX_MIB_LOCKDROPPEDICMPS);
507 }
508 if (sk->sk_state == TCP_CLOSE)
509 goto out;
510
511 if (unlikely(iph->ttl < inet_sk(sk)->min_ttl)) {
512 __NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP);
513 goto out;
514 }
515
516 tp = tcp_sk(sk);
517 /* XXX (TFO) - tp->snd_una should be ISN (tcp_create_openreq_child() */
518 fastopen = rcu_dereference(tp->fastopen_rsk);
519 snd_una = fastopen ? tcp_rsk(fastopen)->snt_isn : tp->snd_una;
520 if (sk->sk_state != TCP_LISTEN &&
521 !between(seq, snd_una, tp->snd_nxt)) {
522 __NET_INC_STATS(net, LINUX_MIB_OUTOFWINDOWICMPS);
523 goto out;
524 }
525
526 switch (type) {
527 case ICMP_REDIRECT:
528 if (!sock_owned_by_user(sk))
529 do_redirect(skb, sk);
530 goto out;
531 case ICMP_SOURCE_QUENCH:
532 /* Just silently ignore these. */
533 goto out;
534 case ICMP_PARAMETERPROB:
535 err = EPROTO;
536 break;
537 case ICMP_DEST_UNREACH:
538 if (code > NR_ICMP_UNREACH)
539 goto out;
540
541 if (code == ICMP_FRAG_NEEDED) { /* PMTU discovery (RFC1191) */
542 /* We are not interested in TCP_LISTEN and open_requests
543 * (SYN-ACKs send out by Linux are always <576bytes so
544 * they should go through unfragmented).
545 */
546 if (sk->sk_state == TCP_LISTEN)
547 goto out;
548
549 WRITE_ONCE(tp->mtu_info, info);
550 if (!sock_owned_by_user(sk)) {
551 tcp_v4_mtu_reduced(sk);
552 } else {
553 if (!test_and_set_bit(TCP_MTU_REDUCED_DEFERRED, &sk->sk_tsq_flags))
554 sock_hold(sk);
555 }
556 goto out;
557 }
558
559 err = icmp_err_convert[code].errno;
560 /* check if this ICMP message allows revert of backoff.
561 * (see RFC 6069)
562 */
563 if (!fastopen &&
564 (code == ICMP_NET_UNREACH || code == ICMP_HOST_UNREACH))
565 tcp_ld_RTO_revert(sk, seq);
566 break;
567 case ICMP_TIME_EXCEEDED:
568 err = EHOSTUNREACH;
569 break;
570 default:
571 goto out;
572 }
573
574 switch (sk->sk_state) {
575 case TCP_SYN_SENT:
576 case TCP_SYN_RECV:
577 /* Only in fast or simultaneous open. If a fast open socket is
578 * already accepted it is treated as a connected one below.
579 */
580 if (fastopen && !fastopen->sk)
581 break;
582
583 ip_icmp_error(sk, skb, err, th->dest, info, (u8 *)th);
584
585 if (!sock_owned_by_user(sk)) {
586 sk->sk_err = err;
587
588 sk_error_report(sk);
589
590 tcp_done(sk);
591 } else {
592 sk->sk_err_soft = err;
593 }
594 goto out;
595 }
596
597 /* If we've already connected we will keep trying
598 * until we time out, or the user gives up.
599 *
600 * rfc1122 4.2.3.9 allows to consider as hard errors
601 * only PROTO_UNREACH and PORT_UNREACH (well, FRAG_FAILED too,
602 * but it is obsoleted by pmtu discovery).
603 *
604 * Note, that in modern internet, where routing is unreliable
605 * and in each dark corner broken firewalls sit, sending random
606 * errors ordered by their masters even this two messages finally lose
607 * their original sense (even Linux sends invalid PORT_UNREACHs)
608 *
609 * Now we are in compliance with RFCs.
610 * --ANK (980905)
611 */
612
613 inet = inet_sk(sk);
614 if (!sock_owned_by_user(sk) && inet->recverr) {
615 sk->sk_err = err;
616 sk_error_report(sk);
617 } else { /* Only an error on timeout */
618 sk->sk_err_soft = err;
619 }
620
621out:
622 bh_unlock_sock(sk);
623 sock_put(sk);
624 return 0;
625}
626
627void __tcp_v4_send_check(struct sk_buff *skb, __be32 saddr, __be32 daddr)
628{
629 struct tcphdr *th = tcp_hdr(skb);
630
631 th->check = ~tcp_v4_check(skb->len, saddr, daddr, 0);
632 skb->csum_start = skb_transport_header(skb) - skb->head;
633 skb->csum_offset = offsetof(struct tcphdr, check);
634}
635
636/* This routine computes an IPv4 TCP checksum. */
637void tcp_v4_send_check(struct sock *sk, struct sk_buff *skb)
638{
639 const struct inet_sock *inet = inet_sk(sk);
640
641 __tcp_v4_send_check(skb, inet->inet_saddr, inet->inet_daddr);
642}
643EXPORT_SYMBOL(tcp_v4_send_check);
644
645/*
646 * This routine will send an RST to the other tcp.
647 *
648 * Someone asks: why I NEVER use socket parameters (TOS, TTL etc.)
649 * for reset.
650 * Answer: if a packet caused RST, it is not for a socket
651 * existing in our system, if it is matched to a socket,
652 * it is just duplicate segment or bug in other side's TCP.
653 * So that we build reply only basing on parameters
654 * arrived with segment.
655 * Exception: precedence violation. We do not implement it in any case.
656 */
657
658#ifdef CONFIG_TCP_MD5SIG
659#define OPTION_BYTES TCPOLEN_MD5SIG_ALIGNED
660#else
661#define OPTION_BYTES sizeof(__be32)
662#endif
663
664static void tcp_v4_send_reset(const struct sock *sk, struct sk_buff *skb)
665{
666 const struct tcphdr *th = tcp_hdr(skb);
667 struct {
668 struct tcphdr th;
669 __be32 opt[OPTION_BYTES / sizeof(__be32)];
670 } rep;
671 struct ip_reply_arg arg;
672#ifdef CONFIG_TCP_MD5SIG
673 struct tcp_md5sig_key *key = NULL;
674 const __u8 *hash_location = NULL;
675 unsigned char newhash[16];
676 int genhash;
677 struct sock *sk1 = NULL;
678#endif
679 u64 transmit_time = 0;
680 struct sock *ctl_sk;
681 struct net *net;
682
683 /* Never send a reset in response to a reset. */
684 if (th->rst)
685 return;
686
687 /* If sk not NULL, it means we did a successful lookup and incoming
688 * route had to be correct. prequeue might have dropped our dst.
689 */
690 if (!sk && skb_rtable(skb)->rt_type != RTN_LOCAL)
691 return;
692
693 /* Swap the send and the receive. */
694 memset(&rep, 0, sizeof(rep));
695 rep.th.dest = th->source;
696 rep.th.source = th->dest;
697 rep.th.doff = sizeof(struct tcphdr) / 4;
698 rep.th.rst = 1;
699
700 if (th->ack) {
701 rep.th.seq = th->ack_seq;
702 } else {
703 rep.th.ack = 1;
704 rep.th.ack_seq = htonl(ntohl(th->seq) + th->syn + th->fin +
705 skb->len - (th->doff << 2));
706 }
707
708 memset(&arg, 0, sizeof(arg));
709 arg.iov[0].iov_base = (unsigned char *)&rep;
710 arg.iov[0].iov_len = sizeof(rep.th);
711
712 net = sk ? sock_net(sk) : dev_net(skb_dst(skb)->dev);
713#ifdef CONFIG_TCP_MD5SIG
714 rcu_read_lock();
715 hash_location = tcp_parse_md5sig_option(th);
716 if (sk && sk_fullsock(sk)) {
717 const union tcp_md5_addr *addr;
718 int l3index;
719
720 /* sdif set, means packet ingressed via a device
721 * in an L3 domain and inet_iif is set to it.
722 */
723 l3index = tcp_v4_sdif(skb) ? inet_iif(skb) : 0;
724 addr = (union tcp_md5_addr *)&ip_hdr(skb)->saddr;
725 key = tcp_md5_do_lookup(sk, l3index, addr, AF_INET);
726 } else if (hash_location) {
727 const union tcp_md5_addr *addr;
728 int sdif = tcp_v4_sdif(skb);
729 int dif = inet_iif(skb);
730 int l3index;
731
732 /*
733 * active side is lost. Try to find listening socket through
734 * source port, and then find md5 key through listening socket.
735 * we are not loose security here:
736 * Incoming packet is checked with md5 hash with finding key,
737 * no RST generated if md5 hash doesn't match.
738 */
739 sk1 = __inet_lookup_listener(net, &tcp_hashinfo, NULL, 0,
740 ip_hdr(skb)->saddr,
741 th->source, ip_hdr(skb)->daddr,
742 ntohs(th->source), dif, sdif);
743 /* don't send rst if it can't find key */
744 if (!sk1)
745 goto out;
746
747 /* sdif set, means packet ingressed via a device
748 * in an L3 domain and dif is set to it.
749 */
750 l3index = sdif ? dif : 0;
751 addr = (union tcp_md5_addr *)&ip_hdr(skb)->saddr;
752 key = tcp_md5_do_lookup(sk1, l3index, addr, AF_INET);
753 if (!key)
754 goto out;
755
756
757 genhash = tcp_v4_md5_hash_skb(newhash, key, NULL, skb);
758 if (genhash || memcmp(hash_location, newhash, 16) != 0)
759 goto out;
760
761 }
762
763 if (key) {
764 rep.opt[0] = htonl((TCPOPT_NOP << 24) |
765 (TCPOPT_NOP << 16) |
766 (TCPOPT_MD5SIG << 8) |
767 TCPOLEN_MD5SIG);
768 /* Update length and the length the header thinks exists */
769 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED;
770 rep.th.doff = arg.iov[0].iov_len / 4;
771
772 tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[1],
773 key, ip_hdr(skb)->saddr,
774 ip_hdr(skb)->daddr, &rep.th);
775 }
776#endif
777 /* Can't co-exist with TCPMD5, hence check rep.opt[0] */
778 if (rep.opt[0] == 0) {
779 __be32 mrst = mptcp_reset_option(skb);
780
781 if (mrst) {
782 rep.opt[0] = mrst;
783 arg.iov[0].iov_len += sizeof(mrst);
784 rep.th.doff = arg.iov[0].iov_len / 4;
785 }
786 }
787
788 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
789 ip_hdr(skb)->saddr, /* XXX */
790 arg.iov[0].iov_len, IPPROTO_TCP, 0);
791 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
792 arg.flags = (sk && inet_sk_transparent(sk)) ? IP_REPLY_ARG_NOSRCCHECK : 0;
793
794 /* When socket is gone, all binding information is lost.
795 * routing might fail in this case. No choice here, if we choose to force
796 * input interface, we will misroute in case of asymmetric route.
797 */
798 if (sk) {
799 arg.bound_dev_if = sk->sk_bound_dev_if;
800 if (sk_fullsock(sk))
801 trace_tcp_send_reset(sk, skb);
802 }
803
804 BUILD_BUG_ON(offsetof(struct sock, sk_bound_dev_if) !=
805 offsetof(struct inet_timewait_sock, tw_bound_dev_if));
806
807 arg.tos = ip_hdr(skb)->tos;
808 arg.uid = sock_net_uid(net, sk && sk_fullsock(sk) ? sk : NULL);
809 local_bh_disable();
810 ctl_sk = this_cpu_read(*net->ipv4.tcp_sk);
811 if (sk) {
812 ctl_sk->sk_mark = (sk->sk_state == TCP_TIME_WAIT) ?
813 inet_twsk(sk)->tw_mark : sk->sk_mark;
814 ctl_sk->sk_priority = (sk->sk_state == TCP_TIME_WAIT) ?
815 inet_twsk(sk)->tw_priority : sk->sk_priority;
816 transmit_time = tcp_transmit_time(sk);
817 }
818 ip_send_unicast_reply(ctl_sk,
819 skb, &TCP_SKB_CB(skb)->header.h4.opt,
820 ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
821 &arg, arg.iov[0].iov_len,
822 transmit_time);
823
824 ctl_sk->sk_mark = 0;
825 __TCP_INC_STATS(net, TCP_MIB_OUTSEGS);
826 __TCP_INC_STATS(net, TCP_MIB_OUTRSTS);
827 local_bh_enable();
828
829#ifdef CONFIG_TCP_MD5SIG
830out:
831 rcu_read_unlock();
832#endif
833}
834
835/* The code following below sending ACKs in SYN-RECV and TIME-WAIT states
836 outside socket context is ugly, certainly. What can I do?
837 */
838
839static void tcp_v4_send_ack(const struct sock *sk,
840 struct sk_buff *skb, u32 seq, u32 ack,
841 u32 win, u32 tsval, u32 tsecr, int oif,
842 struct tcp_md5sig_key *key,
843 int reply_flags, u8 tos)
844{
845 const struct tcphdr *th = tcp_hdr(skb);
846 struct {
847 struct tcphdr th;
848 __be32 opt[(TCPOLEN_TSTAMP_ALIGNED >> 2)
849#ifdef CONFIG_TCP_MD5SIG
850 + (TCPOLEN_MD5SIG_ALIGNED >> 2)
851#endif
852 ];
853 } rep;
854 struct net *net = sock_net(sk);
855 struct ip_reply_arg arg;
856 struct sock *ctl_sk;
857 u64 transmit_time;
858
859 memset(&rep.th, 0, sizeof(struct tcphdr));
860 memset(&arg, 0, sizeof(arg));
861
862 arg.iov[0].iov_base = (unsigned char *)&rep;
863 arg.iov[0].iov_len = sizeof(rep.th);
864 if (tsecr) {
865 rep.opt[0] = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
866 (TCPOPT_TIMESTAMP << 8) |
867 TCPOLEN_TIMESTAMP);
868 rep.opt[1] = htonl(tsval);
869 rep.opt[2] = htonl(tsecr);
870 arg.iov[0].iov_len += TCPOLEN_TSTAMP_ALIGNED;
871 }
872
873 /* Swap the send and the receive. */
874 rep.th.dest = th->source;
875 rep.th.source = th->dest;
876 rep.th.doff = arg.iov[0].iov_len / 4;
877 rep.th.seq = htonl(seq);
878 rep.th.ack_seq = htonl(ack);
879 rep.th.ack = 1;
880 rep.th.window = htons(win);
881
882#ifdef CONFIG_TCP_MD5SIG
883 if (key) {
884 int offset = (tsecr) ? 3 : 0;
885
886 rep.opt[offset++] = htonl((TCPOPT_NOP << 24) |
887 (TCPOPT_NOP << 16) |
888 (TCPOPT_MD5SIG << 8) |
889 TCPOLEN_MD5SIG);
890 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED;
891 rep.th.doff = arg.iov[0].iov_len/4;
892
893 tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[offset],
894 key, ip_hdr(skb)->saddr,
895 ip_hdr(skb)->daddr, &rep.th);
896 }
897#endif
898 arg.flags = reply_flags;
899 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
900 ip_hdr(skb)->saddr, /* XXX */
901 arg.iov[0].iov_len, IPPROTO_TCP, 0);
902 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
903 if (oif)
904 arg.bound_dev_if = oif;
905 arg.tos = tos;
906 arg.uid = sock_net_uid(net, sk_fullsock(sk) ? sk : NULL);
907 local_bh_disable();
908 ctl_sk = this_cpu_read(*net->ipv4.tcp_sk);
909 ctl_sk->sk_mark = (sk->sk_state == TCP_TIME_WAIT) ?
910 inet_twsk(sk)->tw_mark : sk->sk_mark;
911 ctl_sk->sk_priority = (sk->sk_state == TCP_TIME_WAIT) ?
912 inet_twsk(sk)->tw_priority : sk->sk_priority;
913 transmit_time = tcp_transmit_time(sk);
914 ip_send_unicast_reply(ctl_sk,
915 skb, &TCP_SKB_CB(skb)->header.h4.opt,
916 ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
917 &arg, arg.iov[0].iov_len,
918 transmit_time);
919
920 ctl_sk->sk_mark = 0;
921 __TCP_INC_STATS(net, TCP_MIB_OUTSEGS);
922 local_bh_enable();
923}
924
925static void tcp_v4_timewait_ack(struct sock *sk, struct sk_buff *skb)
926{
927 struct inet_timewait_sock *tw = inet_twsk(sk);
928 struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
929
930 tcp_v4_send_ack(sk, skb,
931 tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
932 tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
933 tcp_time_stamp_raw() + tcptw->tw_ts_offset,
934 tcptw->tw_ts_recent,
935 tw->tw_bound_dev_if,
936 tcp_twsk_md5_key(tcptw),
937 tw->tw_transparent ? IP_REPLY_ARG_NOSRCCHECK : 0,
938 tw->tw_tos
939 );
940
941 inet_twsk_put(tw);
942}
943
944static void tcp_v4_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb,
945 struct request_sock *req)
946{
947 const union tcp_md5_addr *addr;
948 int l3index;
949
950 /* sk->sk_state == TCP_LISTEN -> for regular TCP_SYN_RECV
951 * sk->sk_state == TCP_SYN_RECV -> for Fast Open.
952 */
953 u32 seq = (sk->sk_state == TCP_LISTEN) ? tcp_rsk(req)->snt_isn + 1 :
954 tcp_sk(sk)->snd_nxt;
955
956 /* RFC 7323 2.3
957 * The window field (SEG.WND) of every outgoing segment, with the
958 * exception of <SYN> segments, MUST be right-shifted by
959 * Rcv.Wind.Shift bits:
960 */
961 addr = (union tcp_md5_addr *)&ip_hdr(skb)->saddr;
962 l3index = tcp_v4_sdif(skb) ? inet_iif(skb) : 0;
963 tcp_v4_send_ack(sk, skb, seq,
964 tcp_rsk(req)->rcv_nxt,
965 req->rsk_rcv_wnd >> inet_rsk(req)->rcv_wscale,
966 tcp_time_stamp_raw() + tcp_rsk(req)->ts_off,
967 req->ts_recent,
968 0,
969 tcp_md5_do_lookup(sk, l3index, addr, AF_INET),
970 inet_rsk(req)->no_srccheck ? IP_REPLY_ARG_NOSRCCHECK : 0,
971 ip_hdr(skb)->tos);
972}
973
974/*
975 * Send a SYN-ACK after having received a SYN.
976 * This still operates on a request_sock only, not on a big
977 * socket.
978 */
979static int tcp_v4_send_synack(const struct sock *sk, struct dst_entry *dst,
980 struct flowi *fl,
981 struct request_sock *req,
982 struct tcp_fastopen_cookie *foc,
983 enum tcp_synack_type synack_type,
984 struct sk_buff *syn_skb)
985{
986 const struct inet_request_sock *ireq = inet_rsk(req);
987 struct flowi4 fl4;
988 int err = -1;
989 struct sk_buff *skb;
990 u8 tos;
991
992 /* First, grab a route. */
993 if (!dst && (dst = inet_csk_route_req(sk, &fl4, req)) == NULL)
994 return -1;
995
996 skb = tcp_make_synack(sk, dst, req, foc, synack_type, syn_skb);
997
998 if (skb) {
999 __tcp_v4_send_check(skb, ireq->ir_loc_addr, ireq->ir_rmt_addr);
1000
1001 tos = sock_net(sk)->ipv4.sysctl_tcp_reflect_tos ?
1002 (tcp_rsk(req)->syn_tos & ~INET_ECN_MASK) |
1003 (inet_sk(sk)->tos & INET_ECN_MASK) :
1004 inet_sk(sk)->tos;
1005
1006 if (!INET_ECN_is_capable(tos) &&
1007 tcp_bpf_ca_needs_ecn((struct sock *)req))
1008 tos |= INET_ECN_ECT_0;
1009
1010 rcu_read_lock();
1011 err = ip_build_and_send_pkt(skb, sk, ireq->ir_loc_addr,
1012 ireq->ir_rmt_addr,
1013 rcu_dereference(ireq->ireq_opt),
1014 tos);
1015 rcu_read_unlock();
1016 err = net_xmit_eval(err);
1017 }
1018
1019 return err;
1020}
1021
1022/*
1023 * IPv4 request_sock destructor.
1024 */
1025static void tcp_v4_reqsk_destructor(struct request_sock *req)
1026{
1027 kfree(rcu_dereference_protected(inet_rsk(req)->ireq_opt, 1));
1028}
1029
1030#ifdef CONFIG_TCP_MD5SIG
1031/*
1032 * RFC2385 MD5 checksumming requires a mapping of
1033 * IP address->MD5 Key.
1034 * We need to maintain these in the sk structure.
1035 */
1036
1037DEFINE_STATIC_KEY_FALSE(tcp_md5_needed);
1038EXPORT_SYMBOL(tcp_md5_needed);
1039
1040static bool better_md5_match(struct tcp_md5sig_key *old, struct tcp_md5sig_key *new)
1041{
1042 if (!old)
1043 return true;
1044
1045 /* l3index always overrides non-l3index */
1046 if (old->l3index && new->l3index == 0)
1047 return false;
1048 if (old->l3index == 0 && new->l3index)
1049 return true;
1050
1051 return old->prefixlen < new->prefixlen;
1052}
1053
1054/* Find the Key structure for an address. */
1055struct tcp_md5sig_key *__tcp_md5_do_lookup(const struct sock *sk, int l3index,
1056 const union tcp_md5_addr *addr,
1057 int family)
1058{
1059 const struct tcp_sock *tp = tcp_sk(sk);
1060 struct tcp_md5sig_key *key;
1061 const struct tcp_md5sig_info *md5sig;
1062 __be32 mask;
1063 struct tcp_md5sig_key *best_match = NULL;
1064 bool match;
1065
1066 /* caller either holds rcu_read_lock() or socket lock */
1067 md5sig = rcu_dereference_check(tp->md5sig_info,
1068 lockdep_sock_is_held(sk));
1069 if (!md5sig)
1070 return NULL;
1071
1072 hlist_for_each_entry_rcu(key, &md5sig->head, node,
1073 lockdep_sock_is_held(sk)) {
1074 if (key->family != family)
1075 continue;
1076 if (key->l3index && key->l3index != l3index)
1077 continue;
1078 if (family == AF_INET) {
1079 mask = inet_make_mask(key->prefixlen);
1080 match = (key->addr.a4.s_addr & mask) ==
1081 (addr->a4.s_addr & mask);
1082#if IS_ENABLED(CONFIG_IPV6)
1083 } else if (family == AF_INET6) {
1084 match = ipv6_prefix_equal(&key->addr.a6, &addr->a6,
1085 key->prefixlen);
1086#endif
1087 } else {
1088 match = false;
1089 }
1090
1091 if (match && better_md5_match(best_match, key))
1092 best_match = key;
1093 }
1094 return best_match;
1095}
1096EXPORT_SYMBOL(__tcp_md5_do_lookup);
1097
1098static struct tcp_md5sig_key *tcp_md5_do_lookup_exact(const struct sock *sk,
1099 const union tcp_md5_addr *addr,
1100 int family, u8 prefixlen,
1101 int l3index)
1102{
1103 const struct tcp_sock *tp = tcp_sk(sk);
1104 struct tcp_md5sig_key *key;
1105 unsigned int size = sizeof(struct in_addr);
1106 const struct tcp_md5sig_info *md5sig;
1107
1108 /* caller either holds rcu_read_lock() or socket lock */
1109 md5sig = rcu_dereference_check(tp->md5sig_info,
1110 lockdep_sock_is_held(sk));
1111 if (!md5sig)
1112 return NULL;
1113#if IS_ENABLED(CONFIG_IPV6)
1114 if (family == AF_INET6)
1115 size = sizeof(struct in6_addr);
1116#endif
1117 hlist_for_each_entry_rcu(key, &md5sig->head, node,
1118 lockdep_sock_is_held(sk)) {
1119 if (key->family != family)
1120 continue;
1121 if (key->l3index != l3index)
1122 continue;
1123 if (!memcmp(&key->addr, addr, size) &&
1124 key->prefixlen == prefixlen)
1125 return key;
1126 }
1127 return NULL;
1128}
1129
1130struct tcp_md5sig_key *tcp_v4_md5_lookup(const struct sock *sk,
1131 const struct sock *addr_sk)
1132{
1133 const union tcp_md5_addr *addr;
1134 int l3index;
1135
1136 l3index = l3mdev_master_ifindex_by_index(sock_net(sk),
1137 addr_sk->sk_bound_dev_if);
1138 addr = (const union tcp_md5_addr *)&addr_sk->sk_daddr;
1139 return tcp_md5_do_lookup(sk, l3index, addr, AF_INET);
1140}
1141EXPORT_SYMBOL(tcp_v4_md5_lookup);
1142
1143/* This can be called on a newly created socket, from other files */
1144int tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr,
1145 int family, u8 prefixlen, int l3index,
1146 const u8 *newkey, u8 newkeylen, gfp_t gfp)
1147{
1148 /* Add Key to the list */
1149 struct tcp_md5sig_key *key;
1150 struct tcp_sock *tp = tcp_sk(sk);
1151 struct tcp_md5sig_info *md5sig;
1152
1153 key = tcp_md5_do_lookup_exact(sk, addr, family, prefixlen, l3index);
1154 if (key) {
1155 /* Pre-existing entry - just update that one.
1156 * Note that the key might be used concurrently.
1157 * data_race() is telling kcsan that we do not care of
1158 * key mismatches, since changing MD5 key on live flows
1159 * can lead to packet drops.
1160 */
1161 data_race(memcpy(key->key, newkey, newkeylen));
1162
1163 /* Pairs with READ_ONCE() in tcp_md5_hash_key().
1164 * Also note that a reader could catch new key->keylen value
1165 * but old key->key[], this is the reason we use __GFP_ZERO
1166 * at sock_kmalloc() time below these lines.
1167 */
1168 WRITE_ONCE(key->keylen, newkeylen);
1169
1170 return 0;
1171 }
1172
1173 md5sig = rcu_dereference_protected(tp->md5sig_info,
1174 lockdep_sock_is_held(sk));
1175 if (!md5sig) {
1176 md5sig = kmalloc(sizeof(*md5sig), gfp);
1177 if (!md5sig)
1178 return -ENOMEM;
1179
1180 sk_nocaps_add(sk, NETIF_F_GSO_MASK);
1181 INIT_HLIST_HEAD(&md5sig->head);
1182 rcu_assign_pointer(tp->md5sig_info, md5sig);
1183 }
1184
1185 key = sock_kmalloc(sk, sizeof(*key), gfp | __GFP_ZERO);
1186 if (!key)
1187 return -ENOMEM;
1188 if (!tcp_alloc_md5sig_pool()) {
1189 sock_kfree_s(sk, key, sizeof(*key));
1190 return -ENOMEM;
1191 }
1192
1193 memcpy(key->key, newkey, newkeylen);
1194 key->keylen = newkeylen;
1195 key->family = family;
1196 key->prefixlen = prefixlen;
1197 key->l3index = l3index;
1198 memcpy(&key->addr, addr,
1199 (family == AF_INET6) ? sizeof(struct in6_addr) :
1200 sizeof(struct in_addr));
1201 hlist_add_head_rcu(&key->node, &md5sig->head);
1202 return 0;
1203}
1204EXPORT_SYMBOL(tcp_md5_do_add);
1205
1206int tcp_md5_do_del(struct sock *sk, const union tcp_md5_addr *addr, int family,
1207 u8 prefixlen, int l3index)
1208{
1209 struct tcp_md5sig_key *key;
1210
1211 key = tcp_md5_do_lookup_exact(sk, addr, family, prefixlen, l3index);
1212 if (!key)
1213 return -ENOENT;
1214 hlist_del_rcu(&key->node);
1215 atomic_sub(sizeof(*key), &sk->sk_omem_alloc);
1216 kfree_rcu(key, rcu);
1217 return 0;
1218}
1219EXPORT_SYMBOL(tcp_md5_do_del);
1220
1221static void tcp_clear_md5_list(struct sock *sk)
1222{
1223 struct tcp_sock *tp = tcp_sk(sk);
1224 struct tcp_md5sig_key *key;
1225 struct hlist_node *n;
1226 struct tcp_md5sig_info *md5sig;
1227
1228 md5sig = rcu_dereference_protected(tp->md5sig_info, 1);
1229
1230 hlist_for_each_entry_safe(key, n, &md5sig->head, node) {
1231 hlist_del_rcu(&key->node);
1232 atomic_sub(sizeof(*key), &sk->sk_omem_alloc);
1233 kfree_rcu(key, rcu);
1234 }
1235}
1236
1237static int tcp_v4_parse_md5_keys(struct sock *sk, int optname,
1238 sockptr_t optval, int optlen)
1239{
1240 struct tcp_md5sig cmd;
1241 struct sockaddr_in *sin = (struct sockaddr_in *)&cmd.tcpm_addr;
1242 const union tcp_md5_addr *addr;
1243 u8 prefixlen = 32;
1244 int l3index = 0;
1245
1246 if (optlen < sizeof(cmd))
1247 return -EINVAL;
1248
1249 if (copy_from_sockptr(&cmd, optval, sizeof(cmd)))
1250 return -EFAULT;
1251
1252 if (sin->sin_family != AF_INET)
1253 return -EINVAL;
1254
1255 if (optname == TCP_MD5SIG_EXT &&
1256 cmd.tcpm_flags & TCP_MD5SIG_FLAG_PREFIX) {
1257 prefixlen = cmd.tcpm_prefixlen;
1258 if (prefixlen > 32)
1259 return -EINVAL;
1260 }
1261
1262 if (optname == TCP_MD5SIG_EXT &&
1263 cmd.tcpm_flags & TCP_MD5SIG_FLAG_IFINDEX) {
1264 struct net_device *dev;
1265
1266 rcu_read_lock();
1267 dev = dev_get_by_index_rcu(sock_net(sk), cmd.tcpm_ifindex);
1268 if (dev && netif_is_l3_master(dev))
1269 l3index = dev->ifindex;
1270
1271 rcu_read_unlock();
1272
1273 /* ok to reference set/not set outside of rcu;
1274 * right now device MUST be an L3 master
1275 */
1276 if (!dev || !l3index)
1277 return -EINVAL;
1278 }
1279
1280 addr = (union tcp_md5_addr *)&sin->sin_addr.s_addr;
1281
1282 if (!cmd.tcpm_keylen)
1283 return tcp_md5_do_del(sk, addr, AF_INET, prefixlen, l3index);
1284
1285 if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN)
1286 return -EINVAL;
1287
1288 return tcp_md5_do_add(sk, addr, AF_INET, prefixlen, l3index,
1289 cmd.tcpm_key, cmd.tcpm_keylen, GFP_KERNEL);
1290}
1291
1292static int tcp_v4_md5_hash_headers(struct tcp_md5sig_pool *hp,
1293 __be32 daddr, __be32 saddr,
1294 const struct tcphdr *th, int nbytes)
1295{
1296 struct tcp4_pseudohdr *bp;
1297 struct scatterlist sg;
1298 struct tcphdr *_th;
1299
1300 bp = hp->scratch;
1301 bp->saddr = saddr;
1302 bp->daddr = daddr;
1303 bp->pad = 0;
1304 bp->protocol = IPPROTO_TCP;
1305 bp->len = cpu_to_be16(nbytes);
1306
1307 _th = (struct tcphdr *)(bp + 1);
1308 memcpy(_th, th, sizeof(*th));
1309 _th->check = 0;
1310
1311 sg_init_one(&sg, bp, sizeof(*bp) + sizeof(*th));
1312 ahash_request_set_crypt(hp->md5_req, &sg, NULL,
1313 sizeof(*bp) + sizeof(*th));
1314 return crypto_ahash_update(hp->md5_req);
1315}
1316
1317static int tcp_v4_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key,
1318 __be32 daddr, __be32 saddr, const struct tcphdr *th)
1319{
1320 struct tcp_md5sig_pool *hp;
1321 struct ahash_request *req;
1322
1323 hp = tcp_get_md5sig_pool();
1324 if (!hp)
1325 goto clear_hash_noput;
1326 req = hp->md5_req;
1327
1328 if (crypto_ahash_init(req))
1329 goto clear_hash;
1330 if (tcp_v4_md5_hash_headers(hp, daddr, saddr, th, th->doff << 2))
1331 goto clear_hash;
1332 if (tcp_md5_hash_key(hp, key))
1333 goto clear_hash;
1334 ahash_request_set_crypt(req, NULL, md5_hash, 0);
1335 if (crypto_ahash_final(req))
1336 goto clear_hash;
1337
1338 tcp_put_md5sig_pool();
1339 return 0;
1340
1341clear_hash:
1342 tcp_put_md5sig_pool();
1343clear_hash_noput:
1344 memset(md5_hash, 0, 16);
1345 return 1;
1346}
1347
1348int tcp_v4_md5_hash_skb(char *md5_hash, const struct tcp_md5sig_key *key,
1349 const struct sock *sk,
1350 const struct sk_buff *skb)
1351{
1352 struct tcp_md5sig_pool *hp;
1353 struct ahash_request *req;
1354 const struct tcphdr *th = tcp_hdr(skb);
1355 __be32 saddr, daddr;
1356
1357 if (sk) { /* valid for establish/request sockets */
1358 saddr = sk->sk_rcv_saddr;
1359 daddr = sk->sk_daddr;
1360 } else {
1361 const struct iphdr *iph = ip_hdr(skb);
1362 saddr = iph->saddr;
1363 daddr = iph->daddr;
1364 }
1365
1366 hp = tcp_get_md5sig_pool();
1367 if (!hp)
1368 goto clear_hash_noput;
1369 req = hp->md5_req;
1370
1371 if (crypto_ahash_init(req))
1372 goto clear_hash;
1373
1374 if (tcp_v4_md5_hash_headers(hp, daddr, saddr, th, skb->len))
1375 goto clear_hash;
1376 if (tcp_md5_hash_skb_data(hp, skb, th->doff << 2))
1377 goto clear_hash;
1378 if (tcp_md5_hash_key(hp, key))
1379 goto clear_hash;
1380 ahash_request_set_crypt(req, NULL, md5_hash, 0);
1381 if (crypto_ahash_final(req))
1382 goto clear_hash;
1383
1384 tcp_put_md5sig_pool();
1385 return 0;
1386
1387clear_hash:
1388 tcp_put_md5sig_pool();
1389clear_hash_noput:
1390 memset(md5_hash, 0, 16);
1391 return 1;
1392}
1393EXPORT_SYMBOL(tcp_v4_md5_hash_skb);
1394
1395#endif
1396
1397/* Called with rcu_read_lock() */
1398static bool tcp_v4_inbound_md5_hash(const struct sock *sk,
1399 const struct sk_buff *skb,
1400 int dif, int sdif)
1401{
1402#ifdef CONFIG_TCP_MD5SIG
1403 /*
1404 * This gets called for each TCP segment that arrives
1405 * so we want to be efficient.
1406 * We have 3 drop cases:
1407 * o No MD5 hash and one expected.
1408 * o MD5 hash and we're not expecting one.
1409 * o MD5 hash and its wrong.
1410 */
1411 const __u8 *hash_location = NULL;
1412 struct tcp_md5sig_key *hash_expected;
1413 const struct iphdr *iph = ip_hdr(skb);
1414 const struct tcphdr *th = tcp_hdr(skb);
1415 const union tcp_md5_addr *addr;
1416 unsigned char newhash[16];
1417 int genhash, l3index;
1418
1419 /* sdif set, means packet ingressed via a device
1420 * in an L3 domain and dif is set to the l3mdev
1421 */
1422 l3index = sdif ? dif : 0;
1423
1424 addr = (union tcp_md5_addr *)&iph->saddr;
1425 hash_expected = tcp_md5_do_lookup(sk, l3index, addr, AF_INET);
1426 hash_location = tcp_parse_md5sig_option(th);
1427
1428 /* We've parsed the options - do we have a hash? */
1429 if (!hash_expected && !hash_location)
1430 return false;
1431
1432 if (hash_expected && !hash_location) {
1433 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5NOTFOUND);
1434 return true;
1435 }
1436
1437 if (!hash_expected && hash_location) {
1438 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5UNEXPECTED);
1439 return true;
1440 }
1441
1442 /* Okay, so this is hash_expected and hash_location -
1443 * so we need to calculate the checksum.
1444 */
1445 genhash = tcp_v4_md5_hash_skb(newhash,
1446 hash_expected,
1447 NULL, skb);
1448
1449 if (genhash || memcmp(hash_location, newhash, 16) != 0) {
1450 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5FAILURE);
1451 net_info_ratelimited("MD5 Hash failed for (%pI4, %d)->(%pI4, %d)%s L3 index %d\n",
1452 &iph->saddr, ntohs(th->source),
1453 &iph->daddr, ntohs(th->dest),
1454 genhash ? " tcp_v4_calc_md5_hash failed"
1455 : "", l3index);
1456 return true;
1457 }
1458 return false;
1459#endif
1460 return false;
1461}
1462
1463static void tcp_v4_init_req(struct request_sock *req,
1464 const struct sock *sk_listener,
1465 struct sk_buff *skb)
1466{
1467 struct inet_request_sock *ireq = inet_rsk(req);
1468 struct net *net = sock_net(sk_listener);
1469
1470 sk_rcv_saddr_set(req_to_sk(req), ip_hdr(skb)->daddr);
1471 sk_daddr_set(req_to_sk(req), ip_hdr(skb)->saddr);
1472 RCU_INIT_POINTER(ireq->ireq_opt, tcp_v4_save_options(net, skb));
1473}
1474
1475static struct dst_entry *tcp_v4_route_req(const struct sock *sk,
1476 struct sk_buff *skb,
1477 struct flowi *fl,
1478 struct request_sock *req)
1479{
1480 tcp_v4_init_req(req, sk, skb);
1481
1482 if (security_inet_conn_request(sk, skb, req))
1483 return NULL;
1484
1485 return inet_csk_route_req(sk, &fl->u.ip4, req);
1486}
1487
1488struct request_sock_ops tcp_request_sock_ops __read_mostly = {
1489 .family = PF_INET,
1490 .obj_size = sizeof(struct tcp_request_sock),
1491 .rtx_syn_ack = tcp_rtx_synack,
1492 .send_ack = tcp_v4_reqsk_send_ack,
1493 .destructor = tcp_v4_reqsk_destructor,
1494 .send_reset = tcp_v4_send_reset,
1495 .syn_ack_timeout = tcp_syn_ack_timeout,
1496};
1497
1498const struct tcp_request_sock_ops tcp_request_sock_ipv4_ops = {
1499 .mss_clamp = TCP_MSS_DEFAULT,
1500#ifdef CONFIG_TCP_MD5SIG
1501 .req_md5_lookup = tcp_v4_md5_lookup,
1502 .calc_md5_hash = tcp_v4_md5_hash_skb,
1503#endif
1504#ifdef CONFIG_SYN_COOKIES
1505 .cookie_init_seq = cookie_v4_init_sequence,
1506#endif
1507 .route_req = tcp_v4_route_req,
1508 .init_seq = tcp_v4_init_seq,
1509 .init_ts_off = tcp_v4_init_ts_off,
1510 .send_synack = tcp_v4_send_synack,
1511};
1512
1513int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
1514{
1515 /* Never answer to SYNs send to broadcast or multicast */
1516 if (skb_rtable(skb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
1517 goto drop;
1518
1519 return tcp_conn_request(&tcp_request_sock_ops,
1520 &tcp_request_sock_ipv4_ops, sk, skb);
1521
1522drop:
1523 tcp_listendrop(sk);
1524 return 0;
1525}
1526EXPORT_SYMBOL(tcp_v4_conn_request);
1527
1528
1529/*
1530 * The three way handshake has completed - we got a valid synack -
1531 * now create the new socket.
1532 */
1533struct sock *tcp_v4_syn_recv_sock(const struct sock *sk, struct sk_buff *skb,
1534 struct request_sock *req,
1535 struct dst_entry *dst,
1536 struct request_sock *req_unhash,
1537 bool *own_req)
1538{
1539 struct inet_request_sock *ireq;
1540 bool found_dup_sk = false;
1541 struct inet_sock *newinet;
1542 struct tcp_sock *newtp;
1543 struct sock *newsk;
1544#ifdef CONFIG_TCP_MD5SIG
1545 const union tcp_md5_addr *addr;
1546 struct tcp_md5sig_key *key;
1547 int l3index;
1548#endif
1549 struct ip_options_rcu *inet_opt;
1550
1551 if (sk_acceptq_is_full(sk))
1552 goto exit_overflow;
1553
1554 newsk = tcp_create_openreq_child(sk, req, skb);
1555 if (!newsk)
1556 goto exit_nonewsk;
1557
1558 newsk->sk_gso_type = SKB_GSO_TCPV4;
1559 inet_sk_rx_dst_set(newsk, skb);
1560
1561 newtp = tcp_sk(newsk);
1562 newinet = inet_sk(newsk);
1563 ireq = inet_rsk(req);
1564 sk_daddr_set(newsk, ireq->ir_rmt_addr);
1565 sk_rcv_saddr_set(newsk, ireq->ir_loc_addr);
1566 newsk->sk_bound_dev_if = ireq->ir_iif;
1567 newinet->inet_saddr = ireq->ir_loc_addr;
1568 inet_opt = rcu_dereference(ireq->ireq_opt);
1569 RCU_INIT_POINTER(newinet->inet_opt, inet_opt);
1570 newinet->mc_index = inet_iif(skb);
1571 newinet->mc_ttl = ip_hdr(skb)->ttl;
1572 newinet->rcv_tos = ip_hdr(skb)->tos;
1573 inet_csk(newsk)->icsk_ext_hdr_len = 0;
1574 if (inet_opt)
1575 inet_csk(newsk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
1576 newinet->inet_id = prandom_u32();
1577
1578 /* Set ToS of the new socket based upon the value of incoming SYN.
1579 * ECT bits are set later in tcp_init_transfer().
1580 */
1581 if (sock_net(sk)->ipv4.sysctl_tcp_reflect_tos)
1582 newinet->tos = tcp_rsk(req)->syn_tos & ~INET_ECN_MASK;
1583
1584 if (!dst) {
1585 dst = inet_csk_route_child_sock(sk, newsk, req);
1586 if (!dst)
1587 goto put_and_exit;
1588 } else {
1589 /* syncookie case : see end of cookie_v4_check() */
1590 }
1591 sk_setup_caps(newsk, dst);
1592
1593 tcp_ca_openreq_child(newsk, dst);
1594
1595 tcp_sync_mss(newsk, dst_mtu(dst));
1596 newtp->advmss = tcp_mss_clamp(tcp_sk(sk), dst_metric_advmss(dst));
1597
1598 tcp_initialize_rcv_mss(newsk);
1599
1600#ifdef CONFIG_TCP_MD5SIG
1601 l3index = l3mdev_master_ifindex_by_index(sock_net(sk), ireq->ir_iif);
1602 /* Copy over the MD5 key from the original socket */
1603 addr = (union tcp_md5_addr *)&newinet->inet_daddr;
1604 key = tcp_md5_do_lookup(sk, l3index, addr, AF_INET);
1605 if (key) {
1606 /*
1607 * We're using one, so create a matching key
1608 * on the newsk structure. If we fail to get
1609 * memory, then we end up not copying the key
1610 * across. Shucks.
1611 */
1612 tcp_md5_do_add(newsk, addr, AF_INET, 32, l3index,
1613 key->key, key->keylen, GFP_ATOMIC);
1614 sk_nocaps_add(newsk, NETIF_F_GSO_MASK);
1615 }
1616#endif
1617
1618 if (__inet_inherit_port(sk, newsk) < 0)
1619 goto put_and_exit;
1620 *own_req = inet_ehash_nolisten(newsk, req_to_sk(req_unhash),
1621 &found_dup_sk);
1622 if (likely(*own_req)) {
1623 tcp_move_syn(newtp, req);
1624 ireq->ireq_opt = NULL;
1625 } else {
1626 newinet->inet_opt = NULL;
1627
1628 if (!req_unhash && found_dup_sk) {
1629 /* This code path should only be executed in the
1630 * syncookie case only
1631 */
1632 bh_unlock_sock(newsk);
1633 sock_put(newsk);
1634 newsk = NULL;
1635 }
1636 }
1637 return newsk;
1638
1639exit_overflow:
1640 NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
1641exit_nonewsk:
1642 dst_release(dst);
1643exit:
1644 tcp_listendrop(sk);
1645 return NULL;
1646put_and_exit:
1647 newinet->inet_opt = NULL;
1648 inet_csk_prepare_forced_close(newsk);
1649 tcp_done(newsk);
1650 goto exit;
1651}
1652EXPORT_SYMBOL(tcp_v4_syn_recv_sock);
1653
1654static struct sock *tcp_v4_cookie_check(struct sock *sk, struct sk_buff *skb)
1655{
1656#ifdef CONFIG_SYN_COOKIES
1657 const struct tcphdr *th = tcp_hdr(skb);
1658
1659 if (!th->syn)
1660 sk = cookie_v4_check(sk, skb);
1661#endif
1662 return sk;
1663}
1664
1665u16 tcp_v4_get_syncookie(struct sock *sk, struct iphdr *iph,
1666 struct tcphdr *th, u32 *cookie)
1667{
1668 u16 mss = 0;
1669#ifdef CONFIG_SYN_COOKIES
1670 mss = tcp_get_syncookie_mss(&tcp_request_sock_ops,
1671 &tcp_request_sock_ipv4_ops, sk, th);
1672 if (mss) {
1673 *cookie = __cookie_v4_init_sequence(iph, th, &mss);
1674 tcp_synq_overflow(sk);
1675 }
1676#endif
1677 return mss;
1678}
1679
1680INDIRECT_CALLABLE_DECLARE(struct dst_entry *ipv4_dst_check(struct dst_entry *,
1681 u32));
1682/* The socket must have it's spinlock held when we get
1683 * here, unless it is a TCP_LISTEN socket.
1684 *
1685 * We have a potential double-lock case here, so even when
1686 * doing backlog processing we use the BH locking scheme.
1687 * This is because we cannot sleep with the original spinlock
1688 * held.
1689 */
1690int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
1691{
1692 struct sock *rsk;
1693
1694 if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
1695 struct dst_entry *dst = sk->sk_rx_dst;
1696
1697 sock_rps_save_rxhash(sk, skb);
1698 sk_mark_napi_id(sk, skb);
1699 if (dst) {
1700 if (inet_sk(sk)->rx_dst_ifindex != skb->skb_iif ||
1701 !INDIRECT_CALL_1(dst->ops->check, ipv4_dst_check,
1702 dst, 0)) {
1703 dst_release(dst);
1704 sk->sk_rx_dst = NULL;
1705 }
1706 }
1707 tcp_rcv_established(sk, skb);
1708 return 0;
1709 }
1710
1711 if (tcp_checksum_complete(skb))
1712 goto csum_err;
1713
1714 if (sk->sk_state == TCP_LISTEN) {
1715 struct sock *nsk = tcp_v4_cookie_check(sk, skb);
1716
1717 if (!nsk)
1718 goto discard;
1719 if (nsk != sk) {
1720 if (tcp_child_process(sk, nsk, skb)) {
1721 rsk = nsk;
1722 goto reset;
1723 }
1724 return 0;
1725 }
1726 } else
1727 sock_rps_save_rxhash(sk, skb);
1728
1729 if (tcp_rcv_state_process(sk, skb)) {
1730 rsk = sk;
1731 goto reset;
1732 }
1733 return 0;
1734
1735reset:
1736 tcp_v4_send_reset(rsk, skb);
1737discard:
1738 kfree_skb(skb);
1739 /* Be careful here. If this function gets more complicated and
1740 * gcc suffers from register pressure on the x86, sk (in %ebx)
1741 * might be destroyed here. This current version compiles correctly,
1742 * but you have been warned.
1743 */
1744 return 0;
1745
1746csum_err:
1747 trace_tcp_bad_csum(skb);
1748 TCP_INC_STATS(sock_net(sk), TCP_MIB_CSUMERRORS);
1749 TCP_INC_STATS(sock_net(sk), TCP_MIB_INERRS);
1750 goto discard;
1751}
1752EXPORT_SYMBOL(tcp_v4_do_rcv);
1753
1754int tcp_v4_early_demux(struct sk_buff *skb)
1755{
1756 const struct iphdr *iph;
1757 const struct tcphdr *th;
1758 struct sock *sk;
1759
1760 if (skb->pkt_type != PACKET_HOST)
1761 return 0;
1762
1763 if (!pskb_may_pull(skb, skb_transport_offset(skb) + sizeof(struct tcphdr)))
1764 return 0;
1765
1766 iph = ip_hdr(skb);
1767 th = tcp_hdr(skb);
1768
1769 if (th->doff < sizeof(struct tcphdr) / 4)
1770 return 0;
1771
1772 sk = __inet_lookup_established(dev_net(skb->dev), &tcp_hashinfo,
1773 iph->saddr, th->source,
1774 iph->daddr, ntohs(th->dest),
1775 skb->skb_iif, inet_sdif(skb));
1776 if (sk) {
1777 skb->sk = sk;
1778 skb->destructor = sock_edemux;
1779 if (sk_fullsock(sk)) {
1780 struct dst_entry *dst = READ_ONCE(sk->sk_rx_dst);
1781
1782 if (dst)
1783 dst = dst_check(dst, 0);
1784 if (dst &&
1785 inet_sk(sk)->rx_dst_ifindex == skb->skb_iif)
1786 skb_dst_set_noref(skb, dst);
1787 }
1788 }
1789 return 0;
1790}
1791
1792bool tcp_add_backlog(struct sock *sk, struct sk_buff *skb)
1793{
1794 u32 limit = READ_ONCE(sk->sk_rcvbuf) + READ_ONCE(sk->sk_sndbuf);
1795 u32 tail_gso_size, tail_gso_segs;
1796 struct skb_shared_info *shinfo;
1797 const struct tcphdr *th;
1798 struct tcphdr *thtail;
1799 struct sk_buff *tail;
1800 unsigned int hdrlen;
1801 bool fragstolen;
1802 u32 gso_segs;
1803 u32 gso_size;
1804 int delta;
1805
1806 /* In case all data was pulled from skb frags (in __pskb_pull_tail()),
1807 * we can fix skb->truesize to its real value to avoid future drops.
1808 * This is valid because skb is not yet charged to the socket.
1809 * It has been noticed pure SACK packets were sometimes dropped
1810 * (if cooked by drivers without copybreak feature).
1811 */
1812 skb_condense(skb);
1813
1814 skb_dst_drop(skb);
1815
1816 if (unlikely(tcp_checksum_complete(skb))) {
1817 bh_unlock_sock(sk);
1818 trace_tcp_bad_csum(skb);
1819 __TCP_INC_STATS(sock_net(sk), TCP_MIB_CSUMERRORS);
1820 __TCP_INC_STATS(sock_net(sk), TCP_MIB_INERRS);
1821 return true;
1822 }
1823
1824 /* Attempt coalescing to last skb in backlog, even if we are
1825 * above the limits.
1826 * This is okay because skb capacity is limited to MAX_SKB_FRAGS.
1827 */
1828 th = (const struct tcphdr *)skb->data;
1829 hdrlen = th->doff * 4;
1830
1831 tail = sk->sk_backlog.tail;
1832 if (!tail)
1833 goto no_coalesce;
1834 thtail = (struct tcphdr *)tail->data;
1835
1836 if (TCP_SKB_CB(tail)->end_seq != TCP_SKB_CB(skb)->seq ||
1837 TCP_SKB_CB(tail)->ip_dsfield != TCP_SKB_CB(skb)->ip_dsfield ||
1838 ((TCP_SKB_CB(tail)->tcp_flags |
1839 TCP_SKB_CB(skb)->tcp_flags) & (TCPHDR_SYN | TCPHDR_RST | TCPHDR_URG)) ||
1840 !((TCP_SKB_CB(tail)->tcp_flags &
1841 TCP_SKB_CB(skb)->tcp_flags) & TCPHDR_ACK) ||
1842 ((TCP_SKB_CB(tail)->tcp_flags ^
1843 TCP_SKB_CB(skb)->tcp_flags) & (TCPHDR_ECE | TCPHDR_CWR)) ||
1844#ifdef CONFIG_TLS_DEVICE
1845 tail->decrypted != skb->decrypted ||
1846#endif
1847 thtail->doff != th->doff ||
1848 memcmp(thtail + 1, th + 1, hdrlen - sizeof(*th)))
1849 goto no_coalesce;
1850
1851 __skb_pull(skb, hdrlen);
1852
1853 shinfo = skb_shinfo(skb);
1854 gso_size = shinfo->gso_size ?: skb->len;
1855 gso_segs = shinfo->gso_segs ?: 1;
1856
1857 shinfo = skb_shinfo(tail);
1858 tail_gso_size = shinfo->gso_size ?: (tail->len - hdrlen);
1859 tail_gso_segs = shinfo->gso_segs ?: 1;
1860
1861 if (skb_try_coalesce(tail, skb, &fragstolen, &delta)) {
1862 TCP_SKB_CB(tail)->end_seq = TCP_SKB_CB(skb)->end_seq;
1863
1864 if (likely(!before(TCP_SKB_CB(skb)->ack_seq, TCP_SKB_CB(tail)->ack_seq))) {
1865 TCP_SKB_CB(tail)->ack_seq = TCP_SKB_CB(skb)->ack_seq;
1866 thtail->window = th->window;
1867 }
1868
1869 /* We have to update both TCP_SKB_CB(tail)->tcp_flags and
1870 * thtail->fin, so that the fast path in tcp_rcv_established()
1871 * is not entered if we append a packet with a FIN.
1872 * SYN, RST, URG are not present.
1873 * ACK is set on both packets.
1874 * PSH : we do not really care in TCP stack,
1875 * at least for 'GRO' packets.
1876 */
1877 thtail->fin |= th->fin;
1878 TCP_SKB_CB(tail)->tcp_flags |= TCP_SKB_CB(skb)->tcp_flags;
1879
1880 if (TCP_SKB_CB(skb)->has_rxtstamp) {
1881 TCP_SKB_CB(tail)->has_rxtstamp = true;
1882 tail->tstamp = skb->tstamp;
1883 skb_hwtstamps(tail)->hwtstamp = skb_hwtstamps(skb)->hwtstamp;
1884 }
1885
1886 /* Not as strict as GRO. We only need to carry mss max value */
1887 shinfo->gso_size = max(gso_size, tail_gso_size);
1888 shinfo->gso_segs = min_t(u32, gso_segs + tail_gso_segs, 0xFFFF);
1889
1890 sk->sk_backlog.len += delta;
1891 __NET_INC_STATS(sock_net(sk),
1892 LINUX_MIB_TCPBACKLOGCOALESCE);
1893 kfree_skb_partial(skb, fragstolen);
1894 return false;
1895 }
1896 __skb_push(skb, hdrlen);
1897
1898no_coalesce:
1899 /* Only socket owner can try to collapse/prune rx queues
1900 * to reduce memory overhead, so add a little headroom here.
1901 * Few sockets backlog are possibly concurrently non empty.
1902 */
1903 limit += 64*1024;
1904
1905 if (unlikely(sk_add_backlog(sk, skb, limit))) {
1906 bh_unlock_sock(sk);
1907 __NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPBACKLOGDROP);
1908 return true;
1909 }
1910 return false;
1911}
1912EXPORT_SYMBOL(tcp_add_backlog);
1913
1914int tcp_filter(struct sock *sk, struct sk_buff *skb)
1915{
1916 struct tcphdr *th = (struct tcphdr *)skb->data;
1917
1918 return sk_filter_trim_cap(sk, skb, th->doff * 4);
1919}
1920EXPORT_SYMBOL(tcp_filter);
1921
1922static void tcp_v4_restore_cb(struct sk_buff *skb)
1923{
1924 memmove(IPCB(skb), &TCP_SKB_CB(skb)->header.h4,
1925 sizeof(struct inet_skb_parm));
1926}
1927
1928static void tcp_v4_fill_cb(struct sk_buff *skb, const struct iphdr *iph,
1929 const struct tcphdr *th)
1930{
1931 /* This is tricky : We move IPCB at its correct location into TCP_SKB_CB()
1932 * barrier() makes sure compiler wont play fool^Waliasing games.
1933 */
1934 memmove(&TCP_SKB_CB(skb)->header.h4, IPCB(skb),
1935 sizeof(struct inet_skb_parm));
1936 barrier();
1937
1938 TCP_SKB_CB(skb)->seq = ntohl(th->seq);
1939 TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
1940 skb->len - th->doff * 4);
1941 TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
1942 TCP_SKB_CB(skb)->tcp_flags = tcp_flag_byte(th);
1943 TCP_SKB_CB(skb)->tcp_tw_isn = 0;
1944 TCP_SKB_CB(skb)->ip_dsfield = ipv4_get_dsfield(iph);
1945 TCP_SKB_CB(skb)->sacked = 0;
1946 TCP_SKB_CB(skb)->has_rxtstamp =
1947 skb->tstamp || skb_hwtstamps(skb)->hwtstamp;
1948}
1949
1950/*
1951 * From tcp_input.c
1952 */
1953
1954int tcp_v4_rcv(struct sk_buff *skb)
1955{
1956 struct net *net = dev_net(skb->dev);
1957 struct sk_buff *skb_to_free;
1958 int sdif = inet_sdif(skb);
1959 int dif = inet_iif(skb);
1960 const struct iphdr *iph;
1961 const struct tcphdr *th;
1962 bool refcounted;
1963 struct sock *sk;
1964 int ret;
1965
1966 if (skb->pkt_type != PACKET_HOST)
1967 goto discard_it;
1968
1969 /* Count it even if it's bad */
1970 __TCP_INC_STATS(net, TCP_MIB_INSEGS);
1971
1972 if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
1973 goto discard_it;
1974
1975 th = (const struct tcphdr *)skb->data;
1976
1977 if (unlikely(th->doff < sizeof(struct tcphdr) / 4))
1978 goto bad_packet;
1979 if (!pskb_may_pull(skb, th->doff * 4))
1980 goto discard_it;
1981
1982 /* An explanation is required here, I think.
1983 * Packet length and doff are validated by header prediction,
1984 * provided case of th->doff==0 is eliminated.
1985 * So, we defer the checks. */
1986
1987 if (skb_checksum_init(skb, IPPROTO_TCP, inet_compute_pseudo))
1988 goto csum_error;
1989
1990 th = (const struct tcphdr *)skb->data;
1991 iph = ip_hdr(skb);
1992lookup:
1993 sk = __inet_lookup_skb(&tcp_hashinfo, skb, __tcp_hdrlen(th), th->source,
1994 th->dest, sdif, &refcounted);
1995 if (!sk)
1996 goto no_tcp_socket;
1997
1998process:
1999 if (sk->sk_state == TCP_TIME_WAIT)
2000 goto do_time_wait;
2001
2002 if (sk->sk_state == TCP_NEW_SYN_RECV) {
2003 struct request_sock *req = inet_reqsk(sk);
2004 bool req_stolen = false;
2005 struct sock *nsk;
2006
2007 sk = req->rsk_listener;
2008 if (unlikely(tcp_v4_inbound_md5_hash(sk, skb, dif, sdif))) {
2009 sk_drops_add(sk, skb);
2010 reqsk_put(req);
2011 goto discard_it;
2012 }
2013 if (tcp_checksum_complete(skb)) {
2014 reqsk_put(req);
2015 goto csum_error;
2016 }
2017 if (unlikely(sk->sk_state != TCP_LISTEN)) {
2018 nsk = reuseport_migrate_sock(sk, req_to_sk(req), skb);
2019 if (!nsk) {
2020 inet_csk_reqsk_queue_drop_and_put(sk, req);
2021 goto lookup;
2022 }
2023 sk = nsk;
2024 /* reuseport_migrate_sock() has already held one sk_refcnt
2025 * before returning.
2026 */
2027 } else {
2028 /* We own a reference on the listener, increase it again
2029 * as we might lose it too soon.
2030 */
2031 sock_hold(sk);
2032 }
2033 refcounted = true;
2034 nsk = NULL;
2035 if (!tcp_filter(sk, skb)) {
2036 th = (const struct tcphdr *)skb->data;
2037 iph = ip_hdr(skb);
2038 tcp_v4_fill_cb(skb, iph, th);
2039 nsk = tcp_check_req(sk, skb, req, false, &req_stolen);
2040 }
2041 if (!nsk) {
2042 reqsk_put(req);
2043 if (req_stolen) {
2044 /* Another cpu got exclusive access to req
2045 * and created a full blown socket.
2046 * Try to feed this packet to this socket
2047 * instead of discarding it.
2048 */
2049 tcp_v4_restore_cb(skb);
2050 sock_put(sk);
2051 goto lookup;
2052 }
2053 goto discard_and_relse;
2054 }
2055 if (nsk == sk) {
2056 reqsk_put(req);
2057 tcp_v4_restore_cb(skb);
2058 } else if (tcp_child_process(sk, nsk, skb)) {
2059 tcp_v4_send_reset(nsk, skb);
2060 goto discard_and_relse;
2061 } else {
2062 sock_put(sk);
2063 return 0;
2064 }
2065 }
2066 if (unlikely(iph->ttl < inet_sk(sk)->min_ttl)) {
2067 __NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP);
2068 goto discard_and_relse;
2069 }
2070
2071 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
2072 goto discard_and_relse;
2073
2074 if (tcp_v4_inbound_md5_hash(sk, skb, dif, sdif))
2075 goto discard_and_relse;
2076
2077 nf_reset_ct(skb);
2078
2079 if (tcp_filter(sk, skb))
2080 goto discard_and_relse;
2081 th = (const struct tcphdr *)skb->data;
2082 iph = ip_hdr(skb);
2083 tcp_v4_fill_cb(skb, iph, th);
2084
2085 skb->dev = NULL;
2086
2087 if (sk->sk_state == TCP_LISTEN) {
2088 ret = tcp_v4_do_rcv(sk, skb);
2089 goto put_and_return;
2090 }
2091
2092 sk_incoming_cpu_update(sk);
2093
2094 bh_lock_sock_nested(sk);
2095 tcp_segs_in(tcp_sk(sk), skb);
2096 ret = 0;
2097 if (!sock_owned_by_user(sk)) {
2098 skb_to_free = sk->sk_rx_skb_cache;
2099 sk->sk_rx_skb_cache = NULL;
2100 ret = tcp_v4_do_rcv(sk, skb);
2101 } else {
2102 if (tcp_add_backlog(sk, skb))
2103 goto discard_and_relse;
2104 skb_to_free = NULL;
2105 }
2106 bh_unlock_sock(sk);
2107 if (skb_to_free)
2108 __kfree_skb(skb_to_free);
2109
2110put_and_return:
2111 if (refcounted)
2112 sock_put(sk);
2113
2114 return ret;
2115
2116no_tcp_socket:
2117 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
2118 goto discard_it;
2119
2120 tcp_v4_fill_cb(skb, iph, th);
2121
2122 if (tcp_checksum_complete(skb)) {
2123csum_error:
2124 trace_tcp_bad_csum(skb);
2125 __TCP_INC_STATS(net, TCP_MIB_CSUMERRORS);
2126bad_packet:
2127 __TCP_INC_STATS(net, TCP_MIB_INERRS);
2128 } else {
2129 tcp_v4_send_reset(NULL, skb);
2130 }
2131
2132discard_it:
2133 /* Discard frame. */
2134 kfree_skb(skb);
2135 return 0;
2136
2137discard_and_relse:
2138 sk_drops_add(sk, skb);
2139 if (refcounted)
2140 sock_put(sk);
2141 goto discard_it;
2142
2143do_time_wait:
2144 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
2145 inet_twsk_put(inet_twsk(sk));
2146 goto discard_it;
2147 }
2148
2149 tcp_v4_fill_cb(skb, iph, th);
2150
2151 if (tcp_checksum_complete(skb)) {
2152 inet_twsk_put(inet_twsk(sk));
2153 goto csum_error;
2154 }
2155 switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) {
2156 case TCP_TW_SYN: {
2157 struct sock *sk2 = inet_lookup_listener(dev_net(skb->dev),
2158 &tcp_hashinfo, skb,
2159 __tcp_hdrlen(th),
2160 iph->saddr, th->source,
2161 iph->daddr, th->dest,
2162 inet_iif(skb),
2163 sdif);
2164 if (sk2) {
2165 inet_twsk_deschedule_put(inet_twsk(sk));
2166 sk = sk2;
2167 tcp_v4_restore_cb(skb);
2168 refcounted = false;
2169 goto process;
2170 }
2171 }
2172 /* to ACK */
2173 fallthrough;
2174 case TCP_TW_ACK:
2175 tcp_v4_timewait_ack(sk, skb);
2176 break;
2177 case TCP_TW_RST:
2178 tcp_v4_send_reset(sk, skb);
2179 inet_twsk_deschedule_put(inet_twsk(sk));
2180 goto discard_it;
2181 case TCP_TW_SUCCESS:;
2182 }
2183 goto discard_it;
2184}
2185
2186static struct timewait_sock_ops tcp_timewait_sock_ops = {
2187 .twsk_obj_size = sizeof(struct tcp_timewait_sock),
2188 .twsk_unique = tcp_twsk_unique,
2189 .twsk_destructor= tcp_twsk_destructor,
2190};
2191
2192void inet_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb)
2193{
2194 struct dst_entry *dst = skb_dst(skb);
2195
2196 if (dst && dst_hold_safe(dst)) {
2197 sk->sk_rx_dst = dst;
2198 inet_sk(sk)->rx_dst_ifindex = skb->skb_iif;
2199 }
2200}
2201EXPORT_SYMBOL(inet_sk_rx_dst_set);
2202
2203const struct inet_connection_sock_af_ops ipv4_specific = {
2204 .queue_xmit = ip_queue_xmit,
2205 .send_check = tcp_v4_send_check,
2206 .rebuild_header = inet_sk_rebuild_header,
2207 .sk_rx_dst_set = inet_sk_rx_dst_set,
2208 .conn_request = tcp_v4_conn_request,
2209 .syn_recv_sock = tcp_v4_syn_recv_sock,
2210 .net_header_len = sizeof(struct iphdr),
2211 .setsockopt = ip_setsockopt,
2212 .getsockopt = ip_getsockopt,
2213 .addr2sockaddr = inet_csk_addr2sockaddr,
2214 .sockaddr_len = sizeof(struct sockaddr_in),
2215 .mtu_reduced = tcp_v4_mtu_reduced,
2216};
2217EXPORT_SYMBOL(ipv4_specific);
2218
2219#ifdef CONFIG_TCP_MD5SIG
2220static const struct tcp_sock_af_ops tcp_sock_ipv4_specific = {
2221 .md5_lookup = tcp_v4_md5_lookup,
2222 .calc_md5_hash = tcp_v4_md5_hash_skb,
2223 .md5_parse = tcp_v4_parse_md5_keys,
2224};
2225#endif
2226
2227/* NOTE: A lot of things set to zero explicitly by call to
2228 * sk_alloc() so need not be done here.
2229 */
2230static int tcp_v4_init_sock(struct sock *sk)
2231{
2232 struct inet_connection_sock *icsk = inet_csk(sk);
2233
2234 tcp_init_sock(sk);
2235
2236 icsk->icsk_af_ops = &ipv4_specific;
2237
2238#ifdef CONFIG_TCP_MD5SIG
2239 tcp_sk(sk)->af_specific = &tcp_sock_ipv4_specific;
2240#endif
2241
2242 return 0;
2243}
2244
2245void tcp_v4_destroy_sock(struct sock *sk)
2246{
2247 struct tcp_sock *tp = tcp_sk(sk);
2248
2249 trace_tcp_destroy_sock(sk);
2250
2251 tcp_clear_xmit_timers(sk);
2252
2253 tcp_cleanup_congestion_control(sk);
2254
2255 tcp_cleanup_ulp(sk);
2256
2257 /* Cleanup up the write buffer. */
2258 tcp_write_queue_purge(sk);
2259
2260 /* Check if we want to disable active TFO */
2261 tcp_fastopen_active_disable_ofo_check(sk);
2262
2263 /* Cleans up our, hopefully empty, out_of_order_queue. */
2264 skb_rbtree_purge(&tp->out_of_order_queue);
2265
2266#ifdef CONFIG_TCP_MD5SIG
2267 /* Clean up the MD5 key list, if any */
2268 if (tp->md5sig_info) {
2269 tcp_clear_md5_list(sk);
2270 kfree_rcu(rcu_dereference_protected(tp->md5sig_info, 1), rcu);
2271 tp->md5sig_info = NULL;
2272 }
2273#endif
2274
2275 /* Clean up a referenced TCP bind bucket. */
2276 if (inet_csk(sk)->icsk_bind_hash)
2277 inet_put_port(sk);
2278
2279 BUG_ON(rcu_access_pointer(tp->fastopen_rsk));
2280
2281 /* If socket is aborted during connect operation */
2282 tcp_free_fastopen_req(tp);
2283 tcp_fastopen_destroy_cipher(sk);
2284 tcp_saved_syn_free(tp);
2285
2286 sk_sockets_allocated_dec(sk);
2287}
2288EXPORT_SYMBOL(tcp_v4_destroy_sock);
2289
2290#ifdef CONFIG_PROC_FS
2291/* Proc filesystem TCP sock list dumping. */
2292
2293/*
2294 * Get next listener socket follow cur. If cur is NULL, get first socket
2295 * starting from bucket given in st->bucket; when st->bucket is zero the
2296 * very first socket in the hash table is returned.
2297 */
2298static void *listening_get_next(struct seq_file *seq, void *cur)
2299{
2300 struct tcp_seq_afinfo *afinfo;
2301 struct tcp_iter_state *st = seq->private;
2302 struct net *net = seq_file_net(seq);
2303 struct inet_listen_hashbucket *ilb;
2304 struct hlist_nulls_node *node;
2305 struct sock *sk = cur;
2306
2307 if (st->bpf_seq_afinfo)
2308 afinfo = st->bpf_seq_afinfo;
2309 else
2310 afinfo = PDE_DATA(file_inode(seq->file));
2311
2312 if (!sk) {
2313get_head:
2314 ilb = &tcp_hashinfo.listening_hash[st->bucket];
2315 spin_lock(&ilb->lock);
2316 sk = sk_nulls_head(&ilb->nulls_head);
2317 st->offset = 0;
2318 goto get_sk;
2319 }
2320 ilb = &tcp_hashinfo.listening_hash[st->bucket];
2321 ++st->num;
2322 ++st->offset;
2323
2324 sk = sk_nulls_next(sk);
2325get_sk:
2326 sk_nulls_for_each_from(sk, node) {
2327 if (!net_eq(sock_net(sk), net))
2328 continue;
2329 if (afinfo->family == AF_UNSPEC ||
2330 sk->sk_family == afinfo->family)
2331 return sk;
2332 }
2333 spin_unlock(&ilb->lock);
2334 st->offset = 0;
2335 if (++st->bucket < INET_LHTABLE_SIZE)
2336 goto get_head;
2337 return NULL;
2338}
2339
2340static void *listening_get_idx(struct seq_file *seq, loff_t *pos)
2341{
2342 struct tcp_iter_state *st = seq->private;
2343 void *rc;
2344
2345 st->bucket = 0;
2346 st->offset = 0;
2347 rc = listening_get_next(seq, NULL);
2348
2349 while (rc && *pos) {
2350 rc = listening_get_next(seq, rc);
2351 --*pos;
2352 }
2353 return rc;
2354}
2355
2356static inline bool empty_bucket(const struct tcp_iter_state *st)
2357{
2358 return hlist_nulls_empty(&tcp_hashinfo.ehash[st->bucket].chain);
2359}
2360
2361/*
2362 * Get first established socket starting from bucket given in st->bucket.
2363 * If st->bucket is zero, the very first socket in the hash is returned.
2364 */
2365static void *established_get_first(struct seq_file *seq)
2366{
2367 struct tcp_seq_afinfo *afinfo;
2368 struct tcp_iter_state *st = seq->private;
2369 struct net *net = seq_file_net(seq);
2370 void *rc = NULL;
2371
2372 if (st->bpf_seq_afinfo)
2373 afinfo = st->bpf_seq_afinfo;
2374 else
2375 afinfo = PDE_DATA(file_inode(seq->file));
2376
2377 st->offset = 0;
2378 for (; st->bucket <= tcp_hashinfo.ehash_mask; ++st->bucket) {
2379 struct sock *sk;
2380 struct hlist_nulls_node *node;
2381 spinlock_t *lock = inet_ehash_lockp(&tcp_hashinfo, st->bucket);
2382
2383 /* Lockless fast path for the common case of empty buckets */
2384 if (empty_bucket(st))
2385 continue;
2386
2387 spin_lock_bh(lock);
2388 sk_nulls_for_each(sk, node, &tcp_hashinfo.ehash[st->bucket].chain) {
2389 if ((afinfo->family != AF_UNSPEC &&
2390 sk->sk_family != afinfo->family) ||
2391 !net_eq(sock_net(sk), net)) {
2392 continue;
2393 }
2394 rc = sk;
2395 goto out;
2396 }
2397 spin_unlock_bh(lock);
2398 }
2399out:
2400 return rc;
2401}
2402
2403static void *established_get_next(struct seq_file *seq, void *cur)
2404{
2405 struct tcp_seq_afinfo *afinfo;
2406 struct sock *sk = cur;
2407 struct hlist_nulls_node *node;
2408 struct tcp_iter_state *st = seq->private;
2409 struct net *net = seq_file_net(seq);
2410
2411 if (st->bpf_seq_afinfo)
2412 afinfo = st->bpf_seq_afinfo;
2413 else
2414 afinfo = PDE_DATA(file_inode(seq->file));
2415
2416 ++st->num;
2417 ++st->offset;
2418
2419 sk = sk_nulls_next(sk);
2420
2421 sk_nulls_for_each_from(sk, node) {
2422 if ((afinfo->family == AF_UNSPEC ||
2423 sk->sk_family == afinfo->family) &&
2424 net_eq(sock_net(sk), net))
2425 return sk;
2426 }
2427
2428 spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
2429 ++st->bucket;
2430 return established_get_first(seq);
2431}
2432
2433static void *established_get_idx(struct seq_file *seq, loff_t pos)
2434{
2435 struct tcp_iter_state *st = seq->private;
2436 void *rc;
2437
2438 st->bucket = 0;
2439 rc = established_get_first(seq);
2440
2441 while (rc && pos) {
2442 rc = established_get_next(seq, rc);
2443 --pos;
2444 }
2445 return rc;
2446}
2447
2448static void *tcp_get_idx(struct seq_file *seq, loff_t pos)
2449{
2450 void *rc;
2451 struct tcp_iter_state *st = seq->private;
2452
2453 st->state = TCP_SEQ_STATE_LISTENING;
2454 rc = listening_get_idx(seq, &pos);
2455
2456 if (!rc) {
2457 st->state = TCP_SEQ_STATE_ESTABLISHED;
2458 rc = established_get_idx(seq, pos);
2459 }
2460
2461 return rc;
2462}
2463
2464static void *tcp_seek_last_pos(struct seq_file *seq)
2465{
2466 struct tcp_iter_state *st = seq->private;
2467 int bucket = st->bucket;
2468 int offset = st->offset;
2469 int orig_num = st->num;
2470 void *rc = NULL;
2471
2472 switch (st->state) {
2473 case TCP_SEQ_STATE_LISTENING:
2474 if (st->bucket >= INET_LHTABLE_SIZE)
2475 break;
2476 st->state = TCP_SEQ_STATE_LISTENING;
2477 rc = listening_get_next(seq, NULL);
2478 while (offset-- && rc && bucket == st->bucket)
2479 rc = listening_get_next(seq, rc);
2480 if (rc)
2481 break;
2482 st->bucket = 0;
2483 st->state = TCP_SEQ_STATE_ESTABLISHED;
2484 fallthrough;
2485 case TCP_SEQ_STATE_ESTABLISHED:
2486 if (st->bucket > tcp_hashinfo.ehash_mask)
2487 break;
2488 rc = established_get_first(seq);
2489 while (offset-- && rc && bucket == st->bucket)
2490 rc = established_get_next(seq, rc);
2491 }
2492
2493 st->num = orig_num;
2494
2495 return rc;
2496}
2497
2498void *tcp_seq_start(struct seq_file *seq, loff_t *pos)
2499{
2500 struct tcp_iter_state *st = seq->private;
2501 void *rc;
2502
2503 if (*pos && *pos == st->last_pos) {
2504 rc = tcp_seek_last_pos(seq);
2505 if (rc)
2506 goto out;
2507 }
2508
2509 st->state = TCP_SEQ_STATE_LISTENING;
2510 st->num = 0;
2511 st->bucket = 0;
2512 st->offset = 0;
2513 rc = *pos ? tcp_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
2514
2515out:
2516 st->last_pos = *pos;
2517 return rc;
2518}
2519EXPORT_SYMBOL(tcp_seq_start);
2520
2521void *tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2522{
2523 struct tcp_iter_state *st = seq->private;
2524 void *rc = NULL;
2525
2526 if (v == SEQ_START_TOKEN) {
2527 rc = tcp_get_idx(seq, 0);
2528 goto out;
2529 }
2530
2531 switch (st->state) {
2532 case TCP_SEQ_STATE_LISTENING:
2533 rc = listening_get_next(seq, v);
2534 if (!rc) {
2535 st->state = TCP_SEQ_STATE_ESTABLISHED;
2536 st->bucket = 0;
2537 st->offset = 0;
2538 rc = established_get_first(seq);
2539 }
2540 break;
2541 case TCP_SEQ_STATE_ESTABLISHED:
2542 rc = established_get_next(seq, v);
2543 break;
2544 }
2545out:
2546 ++*pos;
2547 st->last_pos = *pos;
2548 return rc;
2549}
2550EXPORT_SYMBOL(tcp_seq_next);
2551
2552void tcp_seq_stop(struct seq_file *seq, void *v)
2553{
2554 struct tcp_iter_state *st = seq->private;
2555
2556 switch (st->state) {
2557 case TCP_SEQ_STATE_LISTENING:
2558 if (v != SEQ_START_TOKEN)
2559 spin_unlock(&tcp_hashinfo.listening_hash[st->bucket].lock);
2560 break;
2561 case TCP_SEQ_STATE_ESTABLISHED:
2562 if (v)
2563 spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
2564 break;
2565 }
2566}
2567EXPORT_SYMBOL(tcp_seq_stop);
2568
2569static void get_openreq4(const struct request_sock *req,
2570 struct seq_file *f, int i)
2571{
2572 const struct inet_request_sock *ireq = inet_rsk(req);
2573 long delta = req->rsk_timer.expires - jiffies;
2574
2575 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2576 " %02X %08X:%08X %02X:%08lX %08X %5u %8d %u %d %pK",
2577 i,
2578 ireq->ir_loc_addr,
2579 ireq->ir_num,
2580 ireq->ir_rmt_addr,
2581 ntohs(ireq->ir_rmt_port),
2582 TCP_SYN_RECV,
2583 0, 0, /* could print option size, but that is af dependent. */
2584 1, /* timers active (only the expire timer) */
2585 jiffies_delta_to_clock_t(delta),
2586 req->num_timeout,
2587 from_kuid_munged(seq_user_ns(f),
2588 sock_i_uid(req->rsk_listener)),
2589 0, /* non standard timer */
2590 0, /* open_requests have no inode */
2591 0,
2592 req);
2593}
2594
2595static void get_tcp4_sock(struct sock *sk, struct seq_file *f, int i)
2596{
2597 int timer_active;
2598 unsigned long timer_expires;
2599 const struct tcp_sock *tp = tcp_sk(sk);
2600 const struct inet_connection_sock *icsk = inet_csk(sk);
2601 const struct inet_sock *inet = inet_sk(sk);
2602 const struct fastopen_queue *fastopenq = &icsk->icsk_accept_queue.fastopenq;
2603 __be32 dest = inet->inet_daddr;
2604 __be32 src = inet->inet_rcv_saddr;
2605 __u16 destp = ntohs(inet->inet_dport);
2606 __u16 srcp = ntohs(inet->inet_sport);
2607 int rx_queue;
2608 int state;
2609
2610 if (icsk->icsk_pending == ICSK_TIME_RETRANS ||
2611 icsk->icsk_pending == ICSK_TIME_REO_TIMEOUT ||
2612 icsk->icsk_pending == ICSK_TIME_LOSS_PROBE) {
2613 timer_active = 1;
2614 timer_expires = icsk->icsk_timeout;
2615 } else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
2616 timer_active = 4;
2617 timer_expires = icsk->icsk_timeout;
2618 } else if (timer_pending(&sk->sk_timer)) {
2619 timer_active = 2;
2620 timer_expires = sk->sk_timer.expires;
2621 } else {
2622 timer_active = 0;
2623 timer_expires = jiffies;
2624 }
2625
2626 state = inet_sk_state_load(sk);
2627 if (state == TCP_LISTEN)
2628 rx_queue = READ_ONCE(sk->sk_ack_backlog);
2629 else
2630 /* Because we don't lock the socket,
2631 * we might find a transient negative value.
2632 */
2633 rx_queue = max_t(int, READ_ONCE(tp->rcv_nxt) -
2634 READ_ONCE(tp->copied_seq), 0);
2635
2636 seq_printf(f, "%4d: %08X:%04X %08X:%04X %02X %08X:%08X %02X:%08lX "
2637 "%08X %5u %8d %lu %d %pK %lu %lu %u %u %d",
2638 i, src, srcp, dest, destp, state,
2639 READ_ONCE(tp->write_seq) - tp->snd_una,
2640 rx_queue,
2641 timer_active,
2642 jiffies_delta_to_clock_t(timer_expires - jiffies),
2643 icsk->icsk_retransmits,
2644 from_kuid_munged(seq_user_ns(f), sock_i_uid(sk)),
2645 icsk->icsk_probes_out,
2646 sock_i_ino(sk),
2647 refcount_read(&sk->sk_refcnt), sk,
2648 jiffies_to_clock_t(icsk->icsk_rto),
2649 jiffies_to_clock_t(icsk->icsk_ack.ato),
2650 (icsk->icsk_ack.quick << 1) | inet_csk_in_pingpong_mode(sk),
2651 tp->snd_cwnd,
2652 state == TCP_LISTEN ?
2653 fastopenq->max_qlen :
2654 (tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh));
2655}
2656
2657static void get_timewait4_sock(const struct inet_timewait_sock *tw,
2658 struct seq_file *f, int i)
2659{
2660 long delta = tw->tw_timer.expires - jiffies;
2661 __be32 dest, src;
2662 __u16 destp, srcp;
2663
2664 dest = tw->tw_daddr;
2665 src = tw->tw_rcv_saddr;
2666 destp = ntohs(tw->tw_dport);
2667 srcp = ntohs(tw->tw_sport);
2668
2669 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2670 " %02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK",
2671 i, src, srcp, dest, destp, tw->tw_substate, 0, 0,
2672 3, jiffies_delta_to_clock_t(delta), 0, 0, 0, 0,
2673 refcount_read(&tw->tw_refcnt), tw);
2674}
2675
2676#define TMPSZ 150
2677
2678static int tcp4_seq_show(struct seq_file *seq, void *v)
2679{
2680 struct tcp_iter_state *st;
2681 struct sock *sk = v;
2682
2683 seq_setwidth(seq, TMPSZ - 1);
2684 if (v == SEQ_START_TOKEN) {
2685 seq_puts(seq, " sl local_address rem_address st tx_queue "
2686 "rx_queue tr tm->when retrnsmt uid timeout "
2687 "inode");
2688 goto out;
2689 }
2690 st = seq->private;
2691
2692 if (sk->sk_state == TCP_TIME_WAIT)
2693 get_timewait4_sock(v, seq, st->num);
2694 else if (sk->sk_state == TCP_NEW_SYN_RECV)
2695 get_openreq4(v, seq, st->num);
2696 else
2697 get_tcp4_sock(v, seq, st->num);
2698out:
2699 seq_pad(seq, '\n');
2700 return 0;
2701}
2702
2703#ifdef CONFIG_BPF_SYSCALL
2704struct bpf_iter__tcp {
2705 __bpf_md_ptr(struct bpf_iter_meta *, meta);
2706 __bpf_md_ptr(struct sock_common *, sk_common);
2707 uid_t uid __aligned(8);
2708};
2709
2710static int tcp_prog_seq_show(struct bpf_prog *prog, struct bpf_iter_meta *meta,
2711 struct sock_common *sk_common, uid_t uid)
2712{
2713 struct bpf_iter__tcp ctx;
2714
2715 meta->seq_num--; /* skip SEQ_START_TOKEN */
2716 ctx.meta = meta;
2717 ctx.sk_common = sk_common;
2718 ctx.uid = uid;
2719 return bpf_iter_run_prog(prog, &ctx);
2720}
2721
2722static int bpf_iter_tcp_seq_show(struct seq_file *seq, void *v)
2723{
2724 struct bpf_iter_meta meta;
2725 struct bpf_prog *prog;
2726 struct sock *sk = v;
2727 uid_t uid;
2728
2729 if (v == SEQ_START_TOKEN)
2730 return 0;
2731
2732 if (sk->sk_state == TCP_TIME_WAIT) {
2733 uid = 0;
2734 } else if (sk->sk_state == TCP_NEW_SYN_RECV) {
2735 const struct request_sock *req = v;
2736
2737 uid = from_kuid_munged(seq_user_ns(seq),
2738 sock_i_uid(req->rsk_listener));
2739 } else {
2740 uid = from_kuid_munged(seq_user_ns(seq), sock_i_uid(sk));
2741 }
2742
2743 meta.seq = seq;
2744 prog = bpf_iter_get_info(&meta, false);
2745 return tcp_prog_seq_show(prog, &meta, v, uid);
2746}
2747
2748static void bpf_iter_tcp_seq_stop(struct seq_file *seq, void *v)
2749{
2750 struct bpf_iter_meta meta;
2751 struct bpf_prog *prog;
2752
2753 if (!v) {
2754 meta.seq = seq;
2755 prog = bpf_iter_get_info(&meta, true);
2756 if (prog)
2757 (void)tcp_prog_seq_show(prog, &meta, v, 0);
2758 }
2759
2760 tcp_seq_stop(seq, v);
2761}
2762
2763static const struct seq_operations bpf_iter_tcp_seq_ops = {
2764 .show = bpf_iter_tcp_seq_show,
2765 .start = tcp_seq_start,
2766 .next = tcp_seq_next,
2767 .stop = bpf_iter_tcp_seq_stop,
2768};
2769#endif
2770
2771static const struct seq_operations tcp4_seq_ops = {
2772 .show = tcp4_seq_show,
2773 .start = tcp_seq_start,
2774 .next = tcp_seq_next,
2775 .stop = tcp_seq_stop,
2776};
2777
2778static struct tcp_seq_afinfo tcp4_seq_afinfo = {
2779 .family = AF_INET,
2780};
2781
2782static int __net_init tcp4_proc_init_net(struct net *net)
2783{
2784 if (!proc_create_net_data("tcp", 0444, net->proc_net, &tcp4_seq_ops,
2785 sizeof(struct tcp_iter_state), &tcp4_seq_afinfo))
2786 return -ENOMEM;
2787 return 0;
2788}
2789
2790static void __net_exit tcp4_proc_exit_net(struct net *net)
2791{
2792 remove_proc_entry("tcp", net->proc_net);
2793}
2794
2795static struct pernet_operations tcp4_net_ops = {
2796 .init = tcp4_proc_init_net,
2797 .exit = tcp4_proc_exit_net,
2798};
2799
2800int __init tcp4_proc_init(void)
2801{
2802 return register_pernet_subsys(&tcp4_net_ops);
2803}
2804
2805void tcp4_proc_exit(void)
2806{
2807 unregister_pernet_subsys(&tcp4_net_ops);
2808}
2809#endif /* CONFIG_PROC_FS */
2810
2811/* @wake is one when sk_stream_write_space() calls us.
2812 * This sends EPOLLOUT only if notsent_bytes is half the limit.
2813 * This mimics the strategy used in sock_def_write_space().
2814 */
2815bool tcp_stream_memory_free(const struct sock *sk, int wake)
2816{
2817 const struct tcp_sock *tp = tcp_sk(sk);
2818 u32 notsent_bytes = READ_ONCE(tp->write_seq) -
2819 READ_ONCE(tp->snd_nxt);
2820
2821 return (notsent_bytes << wake) < tcp_notsent_lowat(tp);
2822}
2823EXPORT_SYMBOL(tcp_stream_memory_free);
2824
2825struct proto tcp_prot = {
2826 .name = "TCP",
2827 .owner = THIS_MODULE,
2828 .close = tcp_close,
2829 .pre_connect = tcp_v4_pre_connect,
2830 .connect = tcp_v4_connect,
2831 .disconnect = tcp_disconnect,
2832 .accept = inet_csk_accept,
2833 .ioctl = tcp_ioctl,
2834 .init = tcp_v4_init_sock,
2835 .destroy = tcp_v4_destroy_sock,
2836 .shutdown = tcp_shutdown,
2837 .setsockopt = tcp_setsockopt,
2838 .getsockopt = tcp_getsockopt,
2839 .bpf_bypass_getsockopt = tcp_bpf_bypass_getsockopt,
2840 .keepalive = tcp_set_keepalive,
2841 .recvmsg = tcp_recvmsg,
2842 .sendmsg = tcp_sendmsg,
2843 .sendpage = tcp_sendpage,
2844 .backlog_rcv = tcp_v4_do_rcv,
2845 .release_cb = tcp_release_cb,
2846 .hash = inet_hash,
2847 .unhash = inet_unhash,
2848 .get_port = inet_csk_get_port,
2849#ifdef CONFIG_BPF_SYSCALL
2850 .psock_update_sk_prot = tcp_bpf_update_proto,
2851#endif
2852 .enter_memory_pressure = tcp_enter_memory_pressure,
2853 .leave_memory_pressure = tcp_leave_memory_pressure,
2854 .stream_memory_free = tcp_stream_memory_free,
2855 .sockets_allocated = &tcp_sockets_allocated,
2856 .orphan_count = &tcp_orphan_count,
2857 .memory_allocated = &tcp_memory_allocated,
2858 .memory_pressure = &tcp_memory_pressure,
2859 .sysctl_mem = sysctl_tcp_mem,
2860 .sysctl_wmem_offset = offsetof(struct net, ipv4.sysctl_tcp_wmem),
2861 .sysctl_rmem_offset = offsetof(struct net, ipv4.sysctl_tcp_rmem),
2862 .max_header = MAX_TCP_HEADER,
2863 .obj_size = sizeof(struct tcp_sock),
2864 .slab_flags = SLAB_TYPESAFE_BY_RCU,
2865 .twsk_prot = &tcp_timewait_sock_ops,
2866 .rsk_prot = &tcp_request_sock_ops,
2867 .h.hashinfo = &tcp_hashinfo,
2868 .no_autobind = true,
2869 .diag_destroy = tcp_abort,
2870};
2871EXPORT_SYMBOL(tcp_prot);
2872
2873static void __net_exit tcp_sk_exit(struct net *net)
2874{
2875 int cpu;
2876
2877 if (net->ipv4.tcp_congestion_control)
2878 bpf_module_put(net->ipv4.tcp_congestion_control,
2879 net->ipv4.tcp_congestion_control->owner);
2880
2881 for_each_possible_cpu(cpu)
2882 inet_ctl_sock_destroy(*per_cpu_ptr(net->ipv4.tcp_sk, cpu));
2883 free_percpu(net->ipv4.tcp_sk);
2884}
2885
2886static int __net_init tcp_sk_init(struct net *net)
2887{
2888 int res, cpu, cnt;
2889
2890 net->ipv4.tcp_sk = alloc_percpu(struct sock *);
2891 if (!net->ipv4.tcp_sk)
2892 return -ENOMEM;
2893
2894 for_each_possible_cpu(cpu) {
2895 struct sock *sk;
2896
2897 res = inet_ctl_sock_create(&sk, PF_INET, SOCK_RAW,
2898 IPPROTO_TCP, net);
2899 if (res)
2900 goto fail;
2901 sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
2902
2903 /* Please enforce IP_DF and IPID==0 for RST and
2904 * ACK sent in SYN-RECV and TIME-WAIT state.
2905 */
2906 inet_sk(sk)->pmtudisc = IP_PMTUDISC_DO;
2907
2908 *per_cpu_ptr(net->ipv4.tcp_sk, cpu) = sk;
2909 }
2910
2911 net->ipv4.sysctl_tcp_ecn = 2;
2912 net->ipv4.sysctl_tcp_ecn_fallback = 1;
2913
2914 net->ipv4.sysctl_tcp_base_mss = TCP_BASE_MSS;
2915 net->ipv4.sysctl_tcp_min_snd_mss = TCP_MIN_SND_MSS;
2916 net->ipv4.sysctl_tcp_probe_threshold = TCP_PROBE_THRESHOLD;
2917 net->ipv4.sysctl_tcp_probe_interval = TCP_PROBE_INTERVAL;
2918 net->ipv4.sysctl_tcp_mtu_probe_floor = TCP_MIN_SND_MSS;
2919
2920 net->ipv4.sysctl_tcp_keepalive_time = TCP_KEEPALIVE_TIME;
2921 net->ipv4.sysctl_tcp_keepalive_probes = TCP_KEEPALIVE_PROBES;
2922 net->ipv4.sysctl_tcp_keepalive_intvl = TCP_KEEPALIVE_INTVL;
2923
2924 net->ipv4.sysctl_tcp_syn_retries = TCP_SYN_RETRIES;
2925 net->ipv4.sysctl_tcp_synack_retries = TCP_SYNACK_RETRIES;
2926 net->ipv4.sysctl_tcp_syncookies = 1;
2927 net->ipv4.sysctl_tcp_reordering = TCP_FASTRETRANS_THRESH;
2928 net->ipv4.sysctl_tcp_retries1 = TCP_RETR1;
2929 net->ipv4.sysctl_tcp_retries2 = TCP_RETR2;
2930 net->ipv4.sysctl_tcp_orphan_retries = 0;
2931 net->ipv4.sysctl_tcp_fin_timeout = TCP_FIN_TIMEOUT;
2932 net->ipv4.sysctl_tcp_notsent_lowat = UINT_MAX;
2933 net->ipv4.sysctl_tcp_tw_reuse = 2;
2934 net->ipv4.sysctl_tcp_no_ssthresh_metrics_save = 1;
2935
2936 cnt = tcp_hashinfo.ehash_mask + 1;
2937 net->ipv4.tcp_death_row.sysctl_max_tw_buckets = cnt / 2;
2938 net->ipv4.tcp_death_row.hashinfo = &tcp_hashinfo;
2939
2940 net->ipv4.sysctl_max_syn_backlog = max(128, cnt / 128);
2941 net->ipv4.sysctl_tcp_sack = 1;
2942 net->ipv4.sysctl_tcp_window_scaling = 1;
2943 net->ipv4.sysctl_tcp_timestamps = 1;
2944 net->ipv4.sysctl_tcp_early_retrans = 3;
2945 net->ipv4.sysctl_tcp_recovery = TCP_RACK_LOSS_DETECTION;
2946 net->ipv4.sysctl_tcp_slow_start_after_idle = 1; /* By default, RFC2861 behavior. */
2947 net->ipv4.sysctl_tcp_retrans_collapse = 1;
2948 net->ipv4.sysctl_tcp_max_reordering = 300;
2949 net->ipv4.sysctl_tcp_dsack = 1;
2950 net->ipv4.sysctl_tcp_app_win = 31;
2951 net->ipv4.sysctl_tcp_adv_win_scale = 1;
2952 net->ipv4.sysctl_tcp_frto = 2;
2953 net->ipv4.sysctl_tcp_moderate_rcvbuf = 1;
2954 /* This limits the percentage of the congestion window which we
2955 * will allow a single TSO frame to consume. Building TSO frames
2956 * which are too large can cause TCP streams to be bursty.
2957 */
2958 net->ipv4.sysctl_tcp_tso_win_divisor = 3;
2959 /* Default TSQ limit of 16 TSO segments */
2960 net->ipv4.sysctl_tcp_limit_output_bytes = 16 * 65536;
2961 /* rfc5961 challenge ack rate limiting */
2962 net->ipv4.sysctl_tcp_challenge_ack_limit = 1000;
2963 net->ipv4.sysctl_tcp_min_tso_segs = 2;
2964 net->ipv4.sysctl_tcp_min_rtt_wlen = 300;
2965 net->ipv4.sysctl_tcp_autocorking = 1;
2966 net->ipv4.sysctl_tcp_invalid_ratelimit = HZ/2;
2967 net->ipv4.sysctl_tcp_pacing_ss_ratio = 200;
2968 net->ipv4.sysctl_tcp_pacing_ca_ratio = 120;
2969 if (net != &init_net) {
2970 memcpy(net->ipv4.sysctl_tcp_rmem,
2971 init_net.ipv4.sysctl_tcp_rmem,
2972 sizeof(init_net.ipv4.sysctl_tcp_rmem));
2973 memcpy(net->ipv4.sysctl_tcp_wmem,
2974 init_net.ipv4.sysctl_tcp_wmem,
2975 sizeof(init_net.ipv4.sysctl_tcp_wmem));
2976 }
2977 net->ipv4.sysctl_tcp_comp_sack_delay_ns = NSEC_PER_MSEC;
2978 net->ipv4.sysctl_tcp_comp_sack_slack_ns = 100 * NSEC_PER_USEC;
2979 net->ipv4.sysctl_tcp_comp_sack_nr = 44;
2980 net->ipv4.sysctl_tcp_fastopen = TFO_CLIENT_ENABLE;
2981 spin_lock_init(&net->ipv4.tcp_fastopen_ctx_lock);
2982 net->ipv4.sysctl_tcp_fastopen_blackhole_timeout = 0;
2983 atomic_set(&net->ipv4.tfo_active_disable_times, 0);
2984
2985 /* Reno is always built in */
2986 if (!net_eq(net, &init_net) &&
2987 bpf_try_module_get(init_net.ipv4.tcp_congestion_control,
2988 init_net.ipv4.tcp_congestion_control->owner))
2989 net->ipv4.tcp_congestion_control = init_net.ipv4.tcp_congestion_control;
2990 else
2991 net->ipv4.tcp_congestion_control = &tcp_reno;
2992
2993 return 0;
2994fail:
2995 tcp_sk_exit(net);
2996
2997 return res;
2998}
2999
3000static void __net_exit tcp_sk_exit_batch(struct list_head *net_exit_list)
3001{
3002 struct net *net;
3003
3004 inet_twsk_purge(&tcp_hashinfo, AF_INET);
3005
3006 list_for_each_entry(net, net_exit_list, exit_list)
3007 tcp_fastopen_ctx_destroy(net);
3008}
3009
3010static struct pernet_operations __net_initdata tcp_sk_ops = {
3011 .init = tcp_sk_init,
3012 .exit = tcp_sk_exit,
3013 .exit_batch = tcp_sk_exit_batch,
3014};
3015
3016#if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS)
3017DEFINE_BPF_ITER_FUNC(tcp, struct bpf_iter_meta *meta,
3018 struct sock_common *sk_common, uid_t uid)
3019
3020static int bpf_iter_init_tcp(void *priv_data, struct bpf_iter_aux_info *aux)
3021{
3022 struct tcp_iter_state *st = priv_data;
3023 struct tcp_seq_afinfo *afinfo;
3024 int ret;
3025
3026 afinfo = kmalloc(sizeof(*afinfo), GFP_USER | __GFP_NOWARN);
3027 if (!afinfo)
3028 return -ENOMEM;
3029
3030 afinfo->family = AF_UNSPEC;
3031 st->bpf_seq_afinfo = afinfo;
3032 ret = bpf_iter_init_seq_net(priv_data, aux);
3033 if (ret)
3034 kfree(afinfo);
3035 return ret;
3036}
3037
3038static void bpf_iter_fini_tcp(void *priv_data)
3039{
3040 struct tcp_iter_state *st = priv_data;
3041
3042 kfree(st->bpf_seq_afinfo);
3043 bpf_iter_fini_seq_net(priv_data);
3044}
3045
3046static const struct bpf_iter_seq_info tcp_seq_info = {
3047 .seq_ops = &bpf_iter_tcp_seq_ops,
3048 .init_seq_private = bpf_iter_init_tcp,
3049 .fini_seq_private = bpf_iter_fini_tcp,
3050 .seq_priv_size = sizeof(struct tcp_iter_state),
3051};
3052
3053static struct bpf_iter_reg tcp_reg_info = {
3054 .target = "tcp",
3055 .ctx_arg_info_size = 1,
3056 .ctx_arg_info = {
3057 { offsetof(struct bpf_iter__tcp, sk_common),
3058 PTR_TO_BTF_ID_OR_NULL },
3059 },
3060 .seq_info = &tcp_seq_info,
3061};
3062
3063static void __init bpf_iter_register(void)
3064{
3065 tcp_reg_info.ctx_arg_info[0].btf_id = btf_sock_ids[BTF_SOCK_TYPE_SOCK_COMMON];
3066 if (bpf_iter_reg_target(&tcp_reg_info))
3067 pr_warn("Warning: could not register bpf iterator tcp\n");
3068}
3069
3070#endif
3071
3072void __init tcp_v4_init(void)
3073{
3074 if (register_pernet_subsys(&tcp_sk_ops))
3075 panic("Failed to create the TCP control socket.\n");
3076
3077#if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS)
3078 bpf_iter_register();
3079#endif
3080}
1/*
2 * INET An implementation of the TCP/IP protocol suite for the LINUX
3 * operating system. INET is implemented using the BSD Socket
4 * interface as the means of communication with the user level.
5 *
6 * Implementation of the Transmission Control Protocol(TCP).
7 *
8 * IPv4 specific functions
9 *
10 *
11 * code split from:
12 * linux/ipv4/tcp.c
13 * linux/ipv4/tcp_input.c
14 * linux/ipv4/tcp_output.c
15 *
16 * See tcp.c for author information
17 *
18 * This program is free software; you can redistribute it and/or
19 * modify it under the terms of the GNU General Public License
20 * as published by the Free Software Foundation; either version
21 * 2 of the License, or (at your option) any later version.
22 */
23
24/*
25 * Changes:
26 * David S. Miller : New socket lookup architecture.
27 * This code is dedicated to John Dyson.
28 * David S. Miller : Change semantics of established hash,
29 * half is devoted to TIME_WAIT sockets
30 * and the rest go in the other half.
31 * Andi Kleen : Add support for syncookies and fixed
32 * some bugs: ip options weren't passed to
33 * the TCP layer, missed a check for an
34 * ACK bit.
35 * Andi Kleen : Implemented fast path mtu discovery.
36 * Fixed many serious bugs in the
37 * request_sock handling and moved
38 * most of it into the af independent code.
39 * Added tail drop and some other bugfixes.
40 * Added new listen semantics.
41 * Mike McLagan : Routing by source
42 * Juan Jose Ciarlante: ip_dynaddr bits
43 * Andi Kleen: various fixes.
44 * Vitaly E. Lavrov : Transparent proxy revived after year
45 * coma.
46 * Andi Kleen : Fix new listen.
47 * Andi Kleen : Fix accept error reporting.
48 * YOSHIFUJI Hideaki @USAGI and: Support IPV6_V6ONLY socket option, which
49 * Alexey Kuznetsov allow both IPv4 and IPv6 sockets to bind
50 * a single port at the same time.
51 */
52
53#define pr_fmt(fmt) "TCP: " fmt
54
55#include <linux/bottom_half.h>
56#include <linux/types.h>
57#include <linux/fcntl.h>
58#include <linux/module.h>
59#include <linux/random.h>
60#include <linux/cache.h>
61#include <linux/jhash.h>
62#include <linux/init.h>
63#include <linux/times.h>
64#include <linux/slab.h>
65
66#include <net/net_namespace.h>
67#include <net/icmp.h>
68#include <net/inet_hashtables.h>
69#include <net/tcp.h>
70#include <net/transp_v6.h>
71#include <net/ipv6.h>
72#include <net/inet_common.h>
73#include <net/timewait_sock.h>
74#include <net/xfrm.h>
75#include <net/secure_seq.h>
76#include <net/busy_poll.h>
77
78#include <linux/inet.h>
79#include <linux/ipv6.h>
80#include <linux/stddef.h>
81#include <linux/proc_fs.h>
82#include <linux/seq_file.h>
83
84#include <crypto/hash.h>
85#include <linux/scatterlist.h>
86
87int sysctl_tcp_tw_reuse __read_mostly;
88int sysctl_tcp_low_latency __read_mostly;
89EXPORT_SYMBOL(sysctl_tcp_low_latency);
90
91#ifdef CONFIG_TCP_MD5SIG
92static int tcp_v4_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key,
93 __be32 daddr, __be32 saddr, const struct tcphdr *th);
94#endif
95
96struct inet_hashinfo tcp_hashinfo;
97EXPORT_SYMBOL(tcp_hashinfo);
98
99static __u32 tcp_v4_init_sequence(const struct sk_buff *skb)
100{
101 return secure_tcp_sequence_number(ip_hdr(skb)->daddr,
102 ip_hdr(skb)->saddr,
103 tcp_hdr(skb)->dest,
104 tcp_hdr(skb)->source);
105}
106
107int tcp_twsk_unique(struct sock *sk, struct sock *sktw, void *twp)
108{
109 const struct tcp_timewait_sock *tcptw = tcp_twsk(sktw);
110 struct tcp_sock *tp = tcp_sk(sk);
111
112 /* With PAWS, it is safe from the viewpoint
113 of data integrity. Even without PAWS it is safe provided sequence
114 spaces do not overlap i.e. at data rates <= 80Mbit/sec.
115
116 Actually, the idea is close to VJ's one, only timestamp cache is
117 held not per host, but per port pair and TW bucket is used as state
118 holder.
119
120 If TW bucket has been already destroyed we fall back to VJ's scheme
121 and use initial timestamp retrieved from peer table.
122 */
123 if (tcptw->tw_ts_recent_stamp &&
124 (!twp || (sysctl_tcp_tw_reuse &&
125 get_seconds() - tcptw->tw_ts_recent_stamp > 1))) {
126 tp->write_seq = tcptw->tw_snd_nxt + 65535 + 2;
127 if (tp->write_seq == 0)
128 tp->write_seq = 1;
129 tp->rx_opt.ts_recent = tcptw->tw_ts_recent;
130 tp->rx_opt.ts_recent_stamp = tcptw->tw_ts_recent_stamp;
131 sock_hold(sktw);
132 return 1;
133 }
134
135 return 0;
136}
137EXPORT_SYMBOL_GPL(tcp_twsk_unique);
138
139/* This will initiate an outgoing connection. */
140int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
141{
142 struct sockaddr_in *usin = (struct sockaddr_in *)uaddr;
143 struct inet_sock *inet = inet_sk(sk);
144 struct tcp_sock *tp = tcp_sk(sk);
145 __be16 orig_sport, orig_dport;
146 __be32 daddr, nexthop;
147 struct flowi4 *fl4;
148 struct rtable *rt;
149 int err;
150 struct ip_options_rcu *inet_opt;
151
152 if (addr_len < sizeof(struct sockaddr_in))
153 return -EINVAL;
154
155 if (usin->sin_family != AF_INET)
156 return -EAFNOSUPPORT;
157
158 nexthop = daddr = usin->sin_addr.s_addr;
159 inet_opt = rcu_dereference_protected(inet->inet_opt,
160 sock_owned_by_user(sk));
161 if (inet_opt && inet_opt->opt.srr) {
162 if (!daddr)
163 return -EINVAL;
164 nexthop = inet_opt->opt.faddr;
165 }
166
167 orig_sport = inet->inet_sport;
168 orig_dport = usin->sin_port;
169 fl4 = &inet->cork.fl.u.ip4;
170 rt = ip_route_connect(fl4, nexthop, inet->inet_saddr,
171 RT_CONN_FLAGS(sk), sk->sk_bound_dev_if,
172 IPPROTO_TCP,
173 orig_sport, orig_dport, sk);
174 if (IS_ERR(rt)) {
175 err = PTR_ERR(rt);
176 if (err == -ENETUNREACH)
177 IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTNOROUTES);
178 return err;
179 }
180
181 if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) {
182 ip_rt_put(rt);
183 return -ENETUNREACH;
184 }
185
186 if (!inet_opt || !inet_opt->opt.srr)
187 daddr = fl4->daddr;
188
189 if (!inet->inet_saddr)
190 inet->inet_saddr = fl4->saddr;
191 sk_rcv_saddr_set(sk, inet->inet_saddr);
192
193 if (tp->rx_opt.ts_recent_stamp && inet->inet_daddr != daddr) {
194 /* Reset inherited state */
195 tp->rx_opt.ts_recent = 0;
196 tp->rx_opt.ts_recent_stamp = 0;
197 if (likely(!tp->repair))
198 tp->write_seq = 0;
199 }
200
201 if (tcp_death_row.sysctl_tw_recycle &&
202 !tp->rx_opt.ts_recent_stamp && fl4->daddr == daddr)
203 tcp_fetch_timewait_stamp(sk, &rt->dst);
204
205 inet->inet_dport = usin->sin_port;
206 sk_daddr_set(sk, daddr);
207
208 inet_csk(sk)->icsk_ext_hdr_len = 0;
209 if (inet_opt)
210 inet_csk(sk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
211
212 tp->rx_opt.mss_clamp = TCP_MSS_DEFAULT;
213
214 /* Socket identity is still unknown (sport may be zero).
215 * However we set state to SYN-SENT and not releasing socket
216 * lock select source port, enter ourselves into the hash tables and
217 * complete initialization after this.
218 */
219 tcp_set_state(sk, TCP_SYN_SENT);
220 err = inet_hash_connect(&tcp_death_row, sk);
221 if (err)
222 goto failure;
223
224 sk_set_txhash(sk);
225
226 rt = ip_route_newports(fl4, rt, orig_sport, orig_dport,
227 inet->inet_sport, inet->inet_dport, sk);
228 if (IS_ERR(rt)) {
229 err = PTR_ERR(rt);
230 rt = NULL;
231 goto failure;
232 }
233 /* OK, now commit destination to socket. */
234 sk->sk_gso_type = SKB_GSO_TCPV4;
235 sk_setup_caps(sk, &rt->dst);
236
237 if (!tp->write_seq && likely(!tp->repair))
238 tp->write_seq = secure_tcp_sequence_number(inet->inet_saddr,
239 inet->inet_daddr,
240 inet->inet_sport,
241 usin->sin_port);
242
243 inet->inet_id = tp->write_seq ^ jiffies;
244
245 err = tcp_connect(sk);
246
247 rt = NULL;
248 if (err)
249 goto failure;
250
251 return 0;
252
253failure:
254 /*
255 * This unhashes the socket and releases the local port,
256 * if necessary.
257 */
258 tcp_set_state(sk, TCP_CLOSE);
259 ip_rt_put(rt);
260 sk->sk_route_caps = 0;
261 inet->inet_dport = 0;
262 return err;
263}
264EXPORT_SYMBOL(tcp_v4_connect);
265
266/*
267 * This routine reacts to ICMP_FRAG_NEEDED mtu indications as defined in RFC1191.
268 * It can be called through tcp_release_cb() if socket was owned by user
269 * at the time tcp_v4_err() was called to handle ICMP message.
270 */
271void tcp_v4_mtu_reduced(struct sock *sk)
272{
273 struct dst_entry *dst;
274 struct inet_sock *inet = inet_sk(sk);
275 u32 mtu = tcp_sk(sk)->mtu_info;
276
277 dst = inet_csk_update_pmtu(sk, mtu);
278 if (!dst)
279 return;
280
281 /* Something is about to be wrong... Remember soft error
282 * for the case, if this connection will not able to recover.
283 */
284 if (mtu < dst_mtu(dst) && ip_dont_fragment(sk, dst))
285 sk->sk_err_soft = EMSGSIZE;
286
287 mtu = dst_mtu(dst);
288
289 if (inet->pmtudisc != IP_PMTUDISC_DONT &&
290 ip_sk_accept_pmtu(sk) &&
291 inet_csk(sk)->icsk_pmtu_cookie > mtu) {
292 tcp_sync_mss(sk, mtu);
293
294 /* Resend the TCP packet because it's
295 * clear that the old packet has been
296 * dropped. This is the new "fast" path mtu
297 * discovery.
298 */
299 tcp_simple_retransmit(sk);
300 } /* else let the usual retransmit timer handle it */
301}
302EXPORT_SYMBOL(tcp_v4_mtu_reduced);
303
304static void do_redirect(struct sk_buff *skb, struct sock *sk)
305{
306 struct dst_entry *dst = __sk_dst_check(sk, 0);
307
308 if (dst)
309 dst->ops->redirect(dst, sk, skb);
310}
311
312
313/* handle ICMP messages on TCP_NEW_SYN_RECV request sockets */
314void tcp_req_err(struct sock *sk, u32 seq, bool abort)
315{
316 struct request_sock *req = inet_reqsk(sk);
317 struct net *net = sock_net(sk);
318
319 /* ICMPs are not backlogged, hence we cannot get
320 * an established socket here.
321 */
322 if (seq != tcp_rsk(req)->snt_isn) {
323 NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
324 } else if (abort) {
325 /*
326 * Still in SYN_RECV, just remove it silently.
327 * There is no good way to pass the error to the newly
328 * created socket, and POSIX does not want network
329 * errors returned from accept().
330 */
331 inet_csk_reqsk_queue_drop(req->rsk_listener, req);
332 NET_INC_STATS_BH(net, LINUX_MIB_LISTENDROPS);
333 }
334 reqsk_put(req);
335}
336EXPORT_SYMBOL(tcp_req_err);
337
338/*
339 * This routine is called by the ICMP module when it gets some
340 * sort of error condition. If err < 0 then the socket should
341 * be closed and the error returned to the user. If err > 0
342 * it's just the icmp type << 8 | icmp code. After adjustment
343 * header points to the first 8 bytes of the tcp header. We need
344 * to find the appropriate port.
345 *
346 * The locking strategy used here is very "optimistic". When
347 * someone else accesses the socket the ICMP is just dropped
348 * and for some paths there is no check at all.
349 * A more general error queue to queue errors for later handling
350 * is probably better.
351 *
352 */
353
354void tcp_v4_err(struct sk_buff *icmp_skb, u32 info)
355{
356 const struct iphdr *iph = (const struct iphdr *)icmp_skb->data;
357 struct tcphdr *th = (struct tcphdr *)(icmp_skb->data + (iph->ihl << 2));
358 struct inet_connection_sock *icsk;
359 struct tcp_sock *tp;
360 struct inet_sock *inet;
361 const int type = icmp_hdr(icmp_skb)->type;
362 const int code = icmp_hdr(icmp_skb)->code;
363 struct sock *sk;
364 struct sk_buff *skb;
365 struct request_sock *fastopen;
366 __u32 seq, snd_una;
367 __u32 remaining;
368 int err;
369 struct net *net = dev_net(icmp_skb->dev);
370
371 sk = __inet_lookup_established(net, &tcp_hashinfo, iph->daddr,
372 th->dest, iph->saddr, ntohs(th->source),
373 inet_iif(icmp_skb));
374 if (!sk) {
375 ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS);
376 return;
377 }
378 if (sk->sk_state == TCP_TIME_WAIT) {
379 inet_twsk_put(inet_twsk(sk));
380 return;
381 }
382 seq = ntohl(th->seq);
383 if (sk->sk_state == TCP_NEW_SYN_RECV)
384 return tcp_req_err(sk, seq,
385 type == ICMP_PARAMETERPROB ||
386 type == ICMP_TIME_EXCEEDED ||
387 (type == ICMP_DEST_UNREACH &&
388 (code == ICMP_NET_UNREACH ||
389 code == ICMP_HOST_UNREACH)));
390
391 bh_lock_sock(sk);
392 /* If too many ICMPs get dropped on busy
393 * servers this needs to be solved differently.
394 * We do take care of PMTU discovery (RFC1191) special case :
395 * we can receive locally generated ICMP messages while socket is held.
396 */
397 if (sock_owned_by_user(sk)) {
398 if (!(type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED))
399 NET_INC_STATS_BH(net, LINUX_MIB_LOCKDROPPEDICMPS);
400 }
401 if (sk->sk_state == TCP_CLOSE)
402 goto out;
403
404 if (unlikely(iph->ttl < inet_sk(sk)->min_ttl)) {
405 NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP);
406 goto out;
407 }
408
409 icsk = inet_csk(sk);
410 tp = tcp_sk(sk);
411 /* XXX (TFO) - tp->snd_una should be ISN (tcp_create_openreq_child() */
412 fastopen = tp->fastopen_rsk;
413 snd_una = fastopen ? tcp_rsk(fastopen)->snt_isn : tp->snd_una;
414 if (sk->sk_state != TCP_LISTEN &&
415 !between(seq, snd_una, tp->snd_nxt)) {
416 NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
417 goto out;
418 }
419
420 switch (type) {
421 case ICMP_REDIRECT:
422 do_redirect(icmp_skb, sk);
423 goto out;
424 case ICMP_SOURCE_QUENCH:
425 /* Just silently ignore these. */
426 goto out;
427 case ICMP_PARAMETERPROB:
428 err = EPROTO;
429 break;
430 case ICMP_DEST_UNREACH:
431 if (code > NR_ICMP_UNREACH)
432 goto out;
433
434 if (code == ICMP_FRAG_NEEDED) { /* PMTU discovery (RFC1191) */
435 /* We are not interested in TCP_LISTEN and open_requests
436 * (SYN-ACKs send out by Linux are always <576bytes so
437 * they should go through unfragmented).
438 */
439 if (sk->sk_state == TCP_LISTEN)
440 goto out;
441
442 tp->mtu_info = info;
443 if (!sock_owned_by_user(sk)) {
444 tcp_v4_mtu_reduced(sk);
445 } else {
446 if (!test_and_set_bit(TCP_MTU_REDUCED_DEFERRED, &tp->tsq_flags))
447 sock_hold(sk);
448 }
449 goto out;
450 }
451
452 err = icmp_err_convert[code].errno;
453 /* check if icmp_skb allows revert of backoff
454 * (see draft-zimmermann-tcp-lcd) */
455 if (code != ICMP_NET_UNREACH && code != ICMP_HOST_UNREACH)
456 break;
457 if (seq != tp->snd_una || !icsk->icsk_retransmits ||
458 !icsk->icsk_backoff || fastopen)
459 break;
460
461 if (sock_owned_by_user(sk))
462 break;
463
464 icsk->icsk_backoff--;
465 icsk->icsk_rto = tp->srtt_us ? __tcp_set_rto(tp) :
466 TCP_TIMEOUT_INIT;
467 icsk->icsk_rto = inet_csk_rto_backoff(icsk, TCP_RTO_MAX);
468
469 skb = tcp_write_queue_head(sk);
470 BUG_ON(!skb);
471
472 remaining = icsk->icsk_rto -
473 min(icsk->icsk_rto,
474 tcp_time_stamp - tcp_skb_timestamp(skb));
475
476 if (remaining) {
477 inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
478 remaining, TCP_RTO_MAX);
479 } else {
480 /* RTO revert clocked out retransmission.
481 * Will retransmit now */
482 tcp_retransmit_timer(sk);
483 }
484
485 break;
486 case ICMP_TIME_EXCEEDED:
487 err = EHOSTUNREACH;
488 break;
489 default:
490 goto out;
491 }
492
493 switch (sk->sk_state) {
494 case TCP_SYN_SENT:
495 case TCP_SYN_RECV:
496 /* Only in fast or simultaneous open. If a fast open socket is
497 * is already accepted it is treated as a connected one below.
498 */
499 if (fastopen && !fastopen->sk)
500 break;
501
502 if (!sock_owned_by_user(sk)) {
503 sk->sk_err = err;
504
505 sk->sk_error_report(sk);
506
507 tcp_done(sk);
508 } else {
509 sk->sk_err_soft = err;
510 }
511 goto out;
512 }
513
514 /* If we've already connected we will keep trying
515 * until we time out, or the user gives up.
516 *
517 * rfc1122 4.2.3.9 allows to consider as hard errors
518 * only PROTO_UNREACH and PORT_UNREACH (well, FRAG_FAILED too,
519 * but it is obsoleted by pmtu discovery).
520 *
521 * Note, that in modern internet, where routing is unreliable
522 * and in each dark corner broken firewalls sit, sending random
523 * errors ordered by their masters even this two messages finally lose
524 * their original sense (even Linux sends invalid PORT_UNREACHs)
525 *
526 * Now we are in compliance with RFCs.
527 * --ANK (980905)
528 */
529
530 inet = inet_sk(sk);
531 if (!sock_owned_by_user(sk) && inet->recverr) {
532 sk->sk_err = err;
533 sk->sk_error_report(sk);
534 } else { /* Only an error on timeout */
535 sk->sk_err_soft = err;
536 }
537
538out:
539 bh_unlock_sock(sk);
540 sock_put(sk);
541}
542
543void __tcp_v4_send_check(struct sk_buff *skb, __be32 saddr, __be32 daddr)
544{
545 struct tcphdr *th = tcp_hdr(skb);
546
547 if (skb->ip_summed == CHECKSUM_PARTIAL) {
548 th->check = ~tcp_v4_check(skb->len, saddr, daddr, 0);
549 skb->csum_start = skb_transport_header(skb) - skb->head;
550 skb->csum_offset = offsetof(struct tcphdr, check);
551 } else {
552 th->check = tcp_v4_check(skb->len, saddr, daddr,
553 csum_partial(th,
554 th->doff << 2,
555 skb->csum));
556 }
557}
558
559/* This routine computes an IPv4 TCP checksum. */
560void tcp_v4_send_check(struct sock *sk, struct sk_buff *skb)
561{
562 const struct inet_sock *inet = inet_sk(sk);
563
564 __tcp_v4_send_check(skb, inet->inet_saddr, inet->inet_daddr);
565}
566EXPORT_SYMBOL(tcp_v4_send_check);
567
568/*
569 * This routine will send an RST to the other tcp.
570 *
571 * Someone asks: why I NEVER use socket parameters (TOS, TTL etc.)
572 * for reset.
573 * Answer: if a packet caused RST, it is not for a socket
574 * existing in our system, if it is matched to a socket,
575 * it is just duplicate segment or bug in other side's TCP.
576 * So that we build reply only basing on parameters
577 * arrived with segment.
578 * Exception: precedence violation. We do not implement it in any case.
579 */
580
581static void tcp_v4_send_reset(const struct sock *sk, struct sk_buff *skb)
582{
583 const struct tcphdr *th = tcp_hdr(skb);
584 struct {
585 struct tcphdr th;
586#ifdef CONFIG_TCP_MD5SIG
587 __be32 opt[(TCPOLEN_MD5SIG_ALIGNED >> 2)];
588#endif
589 } rep;
590 struct ip_reply_arg arg;
591#ifdef CONFIG_TCP_MD5SIG
592 struct tcp_md5sig_key *key = NULL;
593 const __u8 *hash_location = NULL;
594 unsigned char newhash[16];
595 int genhash;
596 struct sock *sk1 = NULL;
597#endif
598 struct net *net;
599
600 /* Never send a reset in response to a reset. */
601 if (th->rst)
602 return;
603
604 /* If sk not NULL, it means we did a successful lookup and incoming
605 * route had to be correct. prequeue might have dropped our dst.
606 */
607 if (!sk && skb_rtable(skb)->rt_type != RTN_LOCAL)
608 return;
609
610 /* Swap the send and the receive. */
611 memset(&rep, 0, sizeof(rep));
612 rep.th.dest = th->source;
613 rep.th.source = th->dest;
614 rep.th.doff = sizeof(struct tcphdr) / 4;
615 rep.th.rst = 1;
616
617 if (th->ack) {
618 rep.th.seq = th->ack_seq;
619 } else {
620 rep.th.ack = 1;
621 rep.th.ack_seq = htonl(ntohl(th->seq) + th->syn + th->fin +
622 skb->len - (th->doff << 2));
623 }
624
625 memset(&arg, 0, sizeof(arg));
626 arg.iov[0].iov_base = (unsigned char *)&rep;
627 arg.iov[0].iov_len = sizeof(rep.th);
628
629 net = sk ? sock_net(sk) : dev_net(skb_dst(skb)->dev);
630#ifdef CONFIG_TCP_MD5SIG
631 hash_location = tcp_parse_md5sig_option(th);
632 if (sk && sk_fullsock(sk)) {
633 key = tcp_md5_do_lookup(sk, (union tcp_md5_addr *)
634 &ip_hdr(skb)->saddr, AF_INET);
635 } else if (hash_location) {
636 /*
637 * active side is lost. Try to find listening socket through
638 * source port, and then find md5 key through listening socket.
639 * we are not loose security here:
640 * Incoming packet is checked with md5 hash with finding key,
641 * no RST generated if md5 hash doesn't match.
642 */
643 sk1 = __inet_lookup_listener(net, &tcp_hashinfo, NULL, 0,
644 ip_hdr(skb)->saddr,
645 th->source, ip_hdr(skb)->daddr,
646 ntohs(th->source), inet_iif(skb));
647 /* don't send rst if it can't find key */
648 if (!sk1)
649 return;
650 rcu_read_lock();
651 key = tcp_md5_do_lookup(sk1, (union tcp_md5_addr *)
652 &ip_hdr(skb)->saddr, AF_INET);
653 if (!key)
654 goto release_sk1;
655
656 genhash = tcp_v4_md5_hash_skb(newhash, key, NULL, skb);
657 if (genhash || memcmp(hash_location, newhash, 16) != 0)
658 goto release_sk1;
659 }
660
661 if (key) {
662 rep.opt[0] = htonl((TCPOPT_NOP << 24) |
663 (TCPOPT_NOP << 16) |
664 (TCPOPT_MD5SIG << 8) |
665 TCPOLEN_MD5SIG);
666 /* Update length and the length the header thinks exists */
667 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED;
668 rep.th.doff = arg.iov[0].iov_len / 4;
669
670 tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[1],
671 key, ip_hdr(skb)->saddr,
672 ip_hdr(skb)->daddr, &rep.th);
673 }
674#endif
675 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
676 ip_hdr(skb)->saddr, /* XXX */
677 arg.iov[0].iov_len, IPPROTO_TCP, 0);
678 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
679 arg.flags = (sk && inet_sk_transparent(sk)) ? IP_REPLY_ARG_NOSRCCHECK : 0;
680
681 /* When socket is gone, all binding information is lost.
682 * routing might fail in this case. No choice here, if we choose to force
683 * input interface, we will misroute in case of asymmetric route.
684 */
685 if (sk)
686 arg.bound_dev_if = sk->sk_bound_dev_if;
687
688 BUILD_BUG_ON(offsetof(struct sock, sk_bound_dev_if) !=
689 offsetof(struct inet_timewait_sock, tw_bound_dev_if));
690
691 arg.tos = ip_hdr(skb)->tos;
692 ip_send_unicast_reply(*this_cpu_ptr(net->ipv4.tcp_sk),
693 skb, &TCP_SKB_CB(skb)->header.h4.opt,
694 ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
695 &arg, arg.iov[0].iov_len);
696
697 TCP_INC_STATS_BH(net, TCP_MIB_OUTSEGS);
698 TCP_INC_STATS_BH(net, TCP_MIB_OUTRSTS);
699
700#ifdef CONFIG_TCP_MD5SIG
701release_sk1:
702 if (sk1) {
703 rcu_read_unlock();
704 sock_put(sk1);
705 }
706#endif
707}
708
709/* The code following below sending ACKs in SYN-RECV and TIME-WAIT states
710 outside socket context is ugly, certainly. What can I do?
711 */
712
713static void tcp_v4_send_ack(struct net *net,
714 struct sk_buff *skb, u32 seq, u32 ack,
715 u32 win, u32 tsval, u32 tsecr, int oif,
716 struct tcp_md5sig_key *key,
717 int reply_flags, u8 tos)
718{
719 const struct tcphdr *th = tcp_hdr(skb);
720 struct {
721 struct tcphdr th;
722 __be32 opt[(TCPOLEN_TSTAMP_ALIGNED >> 2)
723#ifdef CONFIG_TCP_MD5SIG
724 + (TCPOLEN_MD5SIG_ALIGNED >> 2)
725#endif
726 ];
727 } rep;
728 struct ip_reply_arg arg;
729
730 memset(&rep.th, 0, sizeof(struct tcphdr));
731 memset(&arg, 0, sizeof(arg));
732
733 arg.iov[0].iov_base = (unsigned char *)&rep;
734 arg.iov[0].iov_len = sizeof(rep.th);
735 if (tsecr) {
736 rep.opt[0] = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
737 (TCPOPT_TIMESTAMP << 8) |
738 TCPOLEN_TIMESTAMP);
739 rep.opt[1] = htonl(tsval);
740 rep.opt[2] = htonl(tsecr);
741 arg.iov[0].iov_len += TCPOLEN_TSTAMP_ALIGNED;
742 }
743
744 /* Swap the send and the receive. */
745 rep.th.dest = th->source;
746 rep.th.source = th->dest;
747 rep.th.doff = arg.iov[0].iov_len / 4;
748 rep.th.seq = htonl(seq);
749 rep.th.ack_seq = htonl(ack);
750 rep.th.ack = 1;
751 rep.th.window = htons(win);
752
753#ifdef CONFIG_TCP_MD5SIG
754 if (key) {
755 int offset = (tsecr) ? 3 : 0;
756
757 rep.opt[offset++] = htonl((TCPOPT_NOP << 24) |
758 (TCPOPT_NOP << 16) |
759 (TCPOPT_MD5SIG << 8) |
760 TCPOLEN_MD5SIG);
761 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED;
762 rep.th.doff = arg.iov[0].iov_len/4;
763
764 tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[offset],
765 key, ip_hdr(skb)->saddr,
766 ip_hdr(skb)->daddr, &rep.th);
767 }
768#endif
769 arg.flags = reply_flags;
770 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
771 ip_hdr(skb)->saddr, /* XXX */
772 arg.iov[0].iov_len, IPPROTO_TCP, 0);
773 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
774 if (oif)
775 arg.bound_dev_if = oif;
776 arg.tos = tos;
777 ip_send_unicast_reply(*this_cpu_ptr(net->ipv4.tcp_sk),
778 skb, &TCP_SKB_CB(skb)->header.h4.opt,
779 ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
780 &arg, arg.iov[0].iov_len);
781
782 TCP_INC_STATS_BH(net, TCP_MIB_OUTSEGS);
783}
784
785static void tcp_v4_timewait_ack(struct sock *sk, struct sk_buff *skb)
786{
787 struct inet_timewait_sock *tw = inet_twsk(sk);
788 struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
789
790 tcp_v4_send_ack(sock_net(sk), skb,
791 tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
792 tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
793 tcp_time_stamp + tcptw->tw_ts_offset,
794 tcptw->tw_ts_recent,
795 tw->tw_bound_dev_if,
796 tcp_twsk_md5_key(tcptw),
797 tw->tw_transparent ? IP_REPLY_ARG_NOSRCCHECK : 0,
798 tw->tw_tos
799 );
800
801 inet_twsk_put(tw);
802}
803
804static void tcp_v4_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb,
805 struct request_sock *req)
806{
807 /* sk->sk_state == TCP_LISTEN -> for regular TCP_SYN_RECV
808 * sk->sk_state == TCP_SYN_RECV -> for Fast Open.
809 */
810 u32 seq = (sk->sk_state == TCP_LISTEN) ? tcp_rsk(req)->snt_isn + 1 :
811 tcp_sk(sk)->snd_nxt;
812
813 tcp_v4_send_ack(sock_net(sk), skb, seq,
814 tcp_rsk(req)->rcv_nxt, req->rsk_rcv_wnd,
815 tcp_time_stamp,
816 req->ts_recent,
817 0,
818 tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&ip_hdr(skb)->daddr,
819 AF_INET),
820 inet_rsk(req)->no_srccheck ? IP_REPLY_ARG_NOSRCCHECK : 0,
821 ip_hdr(skb)->tos);
822}
823
824/*
825 * Send a SYN-ACK after having received a SYN.
826 * This still operates on a request_sock only, not on a big
827 * socket.
828 */
829static int tcp_v4_send_synack(const struct sock *sk, struct dst_entry *dst,
830 struct flowi *fl,
831 struct request_sock *req,
832 struct tcp_fastopen_cookie *foc,
833 bool attach_req)
834{
835 const struct inet_request_sock *ireq = inet_rsk(req);
836 struct flowi4 fl4;
837 int err = -1;
838 struct sk_buff *skb;
839
840 /* First, grab a route. */
841 if (!dst && (dst = inet_csk_route_req(sk, &fl4, req)) == NULL)
842 return -1;
843
844 skb = tcp_make_synack(sk, dst, req, foc, attach_req);
845
846 if (skb) {
847 __tcp_v4_send_check(skb, ireq->ir_loc_addr, ireq->ir_rmt_addr);
848
849 err = ip_build_and_send_pkt(skb, sk, ireq->ir_loc_addr,
850 ireq->ir_rmt_addr,
851 ireq->opt);
852 err = net_xmit_eval(err);
853 }
854
855 return err;
856}
857
858/*
859 * IPv4 request_sock destructor.
860 */
861static void tcp_v4_reqsk_destructor(struct request_sock *req)
862{
863 kfree(inet_rsk(req)->opt);
864}
865
866#ifdef CONFIG_TCP_MD5SIG
867/*
868 * RFC2385 MD5 checksumming requires a mapping of
869 * IP address->MD5 Key.
870 * We need to maintain these in the sk structure.
871 */
872
873/* Find the Key structure for an address. */
874struct tcp_md5sig_key *tcp_md5_do_lookup(const struct sock *sk,
875 const union tcp_md5_addr *addr,
876 int family)
877{
878 const struct tcp_sock *tp = tcp_sk(sk);
879 struct tcp_md5sig_key *key;
880 unsigned int size = sizeof(struct in_addr);
881 const struct tcp_md5sig_info *md5sig;
882
883 /* caller either holds rcu_read_lock() or socket lock */
884 md5sig = rcu_dereference_check(tp->md5sig_info,
885 sock_owned_by_user(sk) ||
886 lockdep_is_held((spinlock_t *)&sk->sk_lock.slock));
887 if (!md5sig)
888 return NULL;
889#if IS_ENABLED(CONFIG_IPV6)
890 if (family == AF_INET6)
891 size = sizeof(struct in6_addr);
892#endif
893 hlist_for_each_entry_rcu(key, &md5sig->head, node) {
894 if (key->family != family)
895 continue;
896 if (!memcmp(&key->addr, addr, size))
897 return key;
898 }
899 return NULL;
900}
901EXPORT_SYMBOL(tcp_md5_do_lookup);
902
903struct tcp_md5sig_key *tcp_v4_md5_lookup(const struct sock *sk,
904 const struct sock *addr_sk)
905{
906 const union tcp_md5_addr *addr;
907
908 addr = (const union tcp_md5_addr *)&addr_sk->sk_daddr;
909 return tcp_md5_do_lookup(sk, addr, AF_INET);
910}
911EXPORT_SYMBOL(tcp_v4_md5_lookup);
912
913/* This can be called on a newly created socket, from other files */
914int tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr,
915 int family, const u8 *newkey, u8 newkeylen, gfp_t gfp)
916{
917 /* Add Key to the list */
918 struct tcp_md5sig_key *key;
919 struct tcp_sock *tp = tcp_sk(sk);
920 struct tcp_md5sig_info *md5sig;
921
922 key = tcp_md5_do_lookup(sk, addr, family);
923 if (key) {
924 /* Pre-existing entry - just update that one. */
925 memcpy(key->key, newkey, newkeylen);
926 key->keylen = newkeylen;
927 return 0;
928 }
929
930 md5sig = rcu_dereference_protected(tp->md5sig_info,
931 sock_owned_by_user(sk) ||
932 lockdep_is_held(&sk->sk_lock.slock));
933 if (!md5sig) {
934 md5sig = kmalloc(sizeof(*md5sig), gfp);
935 if (!md5sig)
936 return -ENOMEM;
937
938 sk_nocaps_add(sk, NETIF_F_GSO_MASK);
939 INIT_HLIST_HEAD(&md5sig->head);
940 rcu_assign_pointer(tp->md5sig_info, md5sig);
941 }
942
943 key = sock_kmalloc(sk, sizeof(*key), gfp);
944 if (!key)
945 return -ENOMEM;
946 if (!tcp_alloc_md5sig_pool()) {
947 sock_kfree_s(sk, key, sizeof(*key));
948 return -ENOMEM;
949 }
950
951 memcpy(key->key, newkey, newkeylen);
952 key->keylen = newkeylen;
953 key->family = family;
954 memcpy(&key->addr, addr,
955 (family == AF_INET6) ? sizeof(struct in6_addr) :
956 sizeof(struct in_addr));
957 hlist_add_head_rcu(&key->node, &md5sig->head);
958 return 0;
959}
960EXPORT_SYMBOL(tcp_md5_do_add);
961
962int tcp_md5_do_del(struct sock *sk, const union tcp_md5_addr *addr, int family)
963{
964 struct tcp_md5sig_key *key;
965
966 key = tcp_md5_do_lookup(sk, addr, family);
967 if (!key)
968 return -ENOENT;
969 hlist_del_rcu(&key->node);
970 atomic_sub(sizeof(*key), &sk->sk_omem_alloc);
971 kfree_rcu(key, rcu);
972 return 0;
973}
974EXPORT_SYMBOL(tcp_md5_do_del);
975
976static void tcp_clear_md5_list(struct sock *sk)
977{
978 struct tcp_sock *tp = tcp_sk(sk);
979 struct tcp_md5sig_key *key;
980 struct hlist_node *n;
981 struct tcp_md5sig_info *md5sig;
982
983 md5sig = rcu_dereference_protected(tp->md5sig_info, 1);
984
985 hlist_for_each_entry_safe(key, n, &md5sig->head, node) {
986 hlist_del_rcu(&key->node);
987 atomic_sub(sizeof(*key), &sk->sk_omem_alloc);
988 kfree_rcu(key, rcu);
989 }
990}
991
992static int tcp_v4_parse_md5_keys(struct sock *sk, char __user *optval,
993 int optlen)
994{
995 struct tcp_md5sig cmd;
996 struct sockaddr_in *sin = (struct sockaddr_in *)&cmd.tcpm_addr;
997
998 if (optlen < sizeof(cmd))
999 return -EINVAL;
1000
1001 if (copy_from_user(&cmd, optval, sizeof(cmd)))
1002 return -EFAULT;
1003
1004 if (sin->sin_family != AF_INET)
1005 return -EINVAL;
1006
1007 if (!cmd.tcpm_keylen)
1008 return tcp_md5_do_del(sk, (union tcp_md5_addr *)&sin->sin_addr.s_addr,
1009 AF_INET);
1010
1011 if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN)
1012 return -EINVAL;
1013
1014 return tcp_md5_do_add(sk, (union tcp_md5_addr *)&sin->sin_addr.s_addr,
1015 AF_INET, cmd.tcpm_key, cmd.tcpm_keylen,
1016 GFP_KERNEL);
1017}
1018
1019static int tcp_v4_md5_hash_pseudoheader(struct tcp_md5sig_pool *hp,
1020 __be32 daddr, __be32 saddr, int nbytes)
1021{
1022 struct tcp4_pseudohdr *bp;
1023 struct scatterlist sg;
1024
1025 bp = &hp->md5_blk.ip4;
1026
1027 /*
1028 * 1. the TCP pseudo-header (in the order: source IP address,
1029 * destination IP address, zero-padded protocol number, and
1030 * segment length)
1031 */
1032 bp->saddr = saddr;
1033 bp->daddr = daddr;
1034 bp->pad = 0;
1035 bp->protocol = IPPROTO_TCP;
1036 bp->len = cpu_to_be16(nbytes);
1037
1038 sg_init_one(&sg, bp, sizeof(*bp));
1039 ahash_request_set_crypt(hp->md5_req, &sg, NULL, sizeof(*bp));
1040 return crypto_ahash_update(hp->md5_req);
1041}
1042
1043static int tcp_v4_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key,
1044 __be32 daddr, __be32 saddr, const struct tcphdr *th)
1045{
1046 struct tcp_md5sig_pool *hp;
1047 struct ahash_request *req;
1048
1049 hp = tcp_get_md5sig_pool();
1050 if (!hp)
1051 goto clear_hash_noput;
1052 req = hp->md5_req;
1053
1054 if (crypto_ahash_init(req))
1055 goto clear_hash;
1056 if (tcp_v4_md5_hash_pseudoheader(hp, daddr, saddr, th->doff << 2))
1057 goto clear_hash;
1058 if (tcp_md5_hash_header(hp, th))
1059 goto clear_hash;
1060 if (tcp_md5_hash_key(hp, key))
1061 goto clear_hash;
1062 ahash_request_set_crypt(req, NULL, md5_hash, 0);
1063 if (crypto_ahash_final(req))
1064 goto clear_hash;
1065
1066 tcp_put_md5sig_pool();
1067 return 0;
1068
1069clear_hash:
1070 tcp_put_md5sig_pool();
1071clear_hash_noput:
1072 memset(md5_hash, 0, 16);
1073 return 1;
1074}
1075
1076int tcp_v4_md5_hash_skb(char *md5_hash, const struct tcp_md5sig_key *key,
1077 const struct sock *sk,
1078 const struct sk_buff *skb)
1079{
1080 struct tcp_md5sig_pool *hp;
1081 struct ahash_request *req;
1082 const struct tcphdr *th = tcp_hdr(skb);
1083 __be32 saddr, daddr;
1084
1085 if (sk) { /* valid for establish/request sockets */
1086 saddr = sk->sk_rcv_saddr;
1087 daddr = sk->sk_daddr;
1088 } else {
1089 const struct iphdr *iph = ip_hdr(skb);
1090 saddr = iph->saddr;
1091 daddr = iph->daddr;
1092 }
1093
1094 hp = tcp_get_md5sig_pool();
1095 if (!hp)
1096 goto clear_hash_noput;
1097 req = hp->md5_req;
1098
1099 if (crypto_ahash_init(req))
1100 goto clear_hash;
1101
1102 if (tcp_v4_md5_hash_pseudoheader(hp, daddr, saddr, skb->len))
1103 goto clear_hash;
1104 if (tcp_md5_hash_header(hp, th))
1105 goto clear_hash;
1106 if (tcp_md5_hash_skb_data(hp, skb, th->doff << 2))
1107 goto clear_hash;
1108 if (tcp_md5_hash_key(hp, key))
1109 goto clear_hash;
1110 ahash_request_set_crypt(req, NULL, md5_hash, 0);
1111 if (crypto_ahash_final(req))
1112 goto clear_hash;
1113
1114 tcp_put_md5sig_pool();
1115 return 0;
1116
1117clear_hash:
1118 tcp_put_md5sig_pool();
1119clear_hash_noput:
1120 memset(md5_hash, 0, 16);
1121 return 1;
1122}
1123EXPORT_SYMBOL(tcp_v4_md5_hash_skb);
1124
1125#endif
1126
1127/* Called with rcu_read_lock() */
1128static bool tcp_v4_inbound_md5_hash(const struct sock *sk,
1129 const struct sk_buff *skb)
1130{
1131#ifdef CONFIG_TCP_MD5SIG
1132 /*
1133 * This gets called for each TCP segment that arrives
1134 * so we want to be efficient.
1135 * We have 3 drop cases:
1136 * o No MD5 hash and one expected.
1137 * o MD5 hash and we're not expecting one.
1138 * o MD5 hash and its wrong.
1139 */
1140 const __u8 *hash_location = NULL;
1141 struct tcp_md5sig_key *hash_expected;
1142 const struct iphdr *iph = ip_hdr(skb);
1143 const struct tcphdr *th = tcp_hdr(skb);
1144 int genhash;
1145 unsigned char newhash[16];
1146
1147 hash_expected = tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&iph->saddr,
1148 AF_INET);
1149 hash_location = tcp_parse_md5sig_option(th);
1150
1151 /* We've parsed the options - do we have a hash? */
1152 if (!hash_expected && !hash_location)
1153 return false;
1154
1155 if (hash_expected && !hash_location) {
1156 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5NOTFOUND);
1157 return true;
1158 }
1159
1160 if (!hash_expected && hash_location) {
1161 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5UNEXPECTED);
1162 return true;
1163 }
1164
1165 /* Okay, so this is hash_expected and hash_location -
1166 * so we need to calculate the checksum.
1167 */
1168 genhash = tcp_v4_md5_hash_skb(newhash,
1169 hash_expected,
1170 NULL, skb);
1171
1172 if (genhash || memcmp(hash_location, newhash, 16) != 0) {
1173 net_info_ratelimited("MD5 Hash failed for (%pI4, %d)->(%pI4, %d)%s\n",
1174 &iph->saddr, ntohs(th->source),
1175 &iph->daddr, ntohs(th->dest),
1176 genhash ? " tcp_v4_calc_md5_hash failed"
1177 : "");
1178 return true;
1179 }
1180 return false;
1181#endif
1182 return false;
1183}
1184
1185static void tcp_v4_init_req(struct request_sock *req,
1186 const struct sock *sk_listener,
1187 struct sk_buff *skb)
1188{
1189 struct inet_request_sock *ireq = inet_rsk(req);
1190
1191 sk_rcv_saddr_set(req_to_sk(req), ip_hdr(skb)->daddr);
1192 sk_daddr_set(req_to_sk(req), ip_hdr(skb)->saddr);
1193 ireq->no_srccheck = inet_sk(sk_listener)->transparent;
1194 ireq->opt = tcp_v4_save_options(skb);
1195}
1196
1197static struct dst_entry *tcp_v4_route_req(const struct sock *sk,
1198 struct flowi *fl,
1199 const struct request_sock *req,
1200 bool *strict)
1201{
1202 struct dst_entry *dst = inet_csk_route_req(sk, &fl->u.ip4, req);
1203
1204 if (strict) {
1205 if (fl->u.ip4.daddr == inet_rsk(req)->ir_rmt_addr)
1206 *strict = true;
1207 else
1208 *strict = false;
1209 }
1210
1211 return dst;
1212}
1213
1214struct request_sock_ops tcp_request_sock_ops __read_mostly = {
1215 .family = PF_INET,
1216 .obj_size = sizeof(struct tcp_request_sock),
1217 .rtx_syn_ack = tcp_rtx_synack,
1218 .send_ack = tcp_v4_reqsk_send_ack,
1219 .destructor = tcp_v4_reqsk_destructor,
1220 .send_reset = tcp_v4_send_reset,
1221 .syn_ack_timeout = tcp_syn_ack_timeout,
1222};
1223
1224static const struct tcp_request_sock_ops tcp_request_sock_ipv4_ops = {
1225 .mss_clamp = TCP_MSS_DEFAULT,
1226#ifdef CONFIG_TCP_MD5SIG
1227 .req_md5_lookup = tcp_v4_md5_lookup,
1228 .calc_md5_hash = tcp_v4_md5_hash_skb,
1229#endif
1230 .init_req = tcp_v4_init_req,
1231#ifdef CONFIG_SYN_COOKIES
1232 .cookie_init_seq = cookie_v4_init_sequence,
1233#endif
1234 .route_req = tcp_v4_route_req,
1235 .init_seq = tcp_v4_init_sequence,
1236 .send_synack = tcp_v4_send_synack,
1237};
1238
1239int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
1240{
1241 /* Never answer to SYNs send to broadcast or multicast */
1242 if (skb_rtable(skb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
1243 goto drop;
1244
1245 return tcp_conn_request(&tcp_request_sock_ops,
1246 &tcp_request_sock_ipv4_ops, sk, skb);
1247
1248drop:
1249 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
1250 return 0;
1251}
1252EXPORT_SYMBOL(tcp_v4_conn_request);
1253
1254
1255/*
1256 * The three way handshake has completed - we got a valid synack -
1257 * now create the new socket.
1258 */
1259struct sock *tcp_v4_syn_recv_sock(const struct sock *sk, struct sk_buff *skb,
1260 struct request_sock *req,
1261 struct dst_entry *dst,
1262 struct request_sock *req_unhash,
1263 bool *own_req)
1264{
1265 struct inet_request_sock *ireq;
1266 struct inet_sock *newinet;
1267 struct tcp_sock *newtp;
1268 struct sock *newsk;
1269#ifdef CONFIG_TCP_MD5SIG
1270 struct tcp_md5sig_key *key;
1271#endif
1272 struct ip_options_rcu *inet_opt;
1273
1274 if (sk_acceptq_is_full(sk))
1275 goto exit_overflow;
1276
1277 newsk = tcp_create_openreq_child(sk, req, skb);
1278 if (!newsk)
1279 goto exit_nonewsk;
1280
1281 newsk->sk_gso_type = SKB_GSO_TCPV4;
1282 inet_sk_rx_dst_set(newsk, skb);
1283
1284 newtp = tcp_sk(newsk);
1285 newinet = inet_sk(newsk);
1286 ireq = inet_rsk(req);
1287 sk_daddr_set(newsk, ireq->ir_rmt_addr);
1288 sk_rcv_saddr_set(newsk, ireq->ir_loc_addr);
1289 newsk->sk_bound_dev_if = ireq->ir_iif;
1290 newinet->inet_saddr = ireq->ir_loc_addr;
1291 inet_opt = ireq->opt;
1292 rcu_assign_pointer(newinet->inet_opt, inet_opt);
1293 ireq->opt = NULL;
1294 newinet->mc_index = inet_iif(skb);
1295 newinet->mc_ttl = ip_hdr(skb)->ttl;
1296 newinet->rcv_tos = ip_hdr(skb)->tos;
1297 inet_csk(newsk)->icsk_ext_hdr_len = 0;
1298 if (inet_opt)
1299 inet_csk(newsk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
1300 newinet->inet_id = newtp->write_seq ^ jiffies;
1301
1302 if (!dst) {
1303 dst = inet_csk_route_child_sock(sk, newsk, req);
1304 if (!dst)
1305 goto put_and_exit;
1306 } else {
1307 /* syncookie case : see end of cookie_v4_check() */
1308 }
1309 sk_setup_caps(newsk, dst);
1310
1311 tcp_ca_openreq_child(newsk, dst);
1312
1313 tcp_sync_mss(newsk, dst_mtu(dst));
1314 newtp->advmss = dst_metric_advmss(dst);
1315 if (tcp_sk(sk)->rx_opt.user_mss &&
1316 tcp_sk(sk)->rx_opt.user_mss < newtp->advmss)
1317 newtp->advmss = tcp_sk(sk)->rx_opt.user_mss;
1318
1319 tcp_initialize_rcv_mss(newsk);
1320
1321#ifdef CONFIG_TCP_MD5SIG
1322 /* Copy over the MD5 key from the original socket */
1323 key = tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&newinet->inet_daddr,
1324 AF_INET);
1325 if (key) {
1326 /*
1327 * We're using one, so create a matching key
1328 * on the newsk structure. If we fail to get
1329 * memory, then we end up not copying the key
1330 * across. Shucks.
1331 */
1332 tcp_md5_do_add(newsk, (union tcp_md5_addr *)&newinet->inet_daddr,
1333 AF_INET, key->key, key->keylen, GFP_ATOMIC);
1334 sk_nocaps_add(newsk, NETIF_F_GSO_MASK);
1335 }
1336#endif
1337
1338 if (__inet_inherit_port(sk, newsk) < 0)
1339 goto put_and_exit;
1340 *own_req = inet_ehash_nolisten(newsk, req_to_sk(req_unhash));
1341 if (*own_req)
1342 tcp_move_syn(newtp, req);
1343
1344 return newsk;
1345
1346exit_overflow:
1347 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
1348exit_nonewsk:
1349 dst_release(dst);
1350exit:
1351 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
1352 return NULL;
1353put_and_exit:
1354 inet_csk_prepare_forced_close(newsk);
1355 tcp_done(newsk);
1356 goto exit;
1357}
1358EXPORT_SYMBOL(tcp_v4_syn_recv_sock);
1359
1360static struct sock *tcp_v4_cookie_check(struct sock *sk, struct sk_buff *skb)
1361{
1362#ifdef CONFIG_SYN_COOKIES
1363 const struct tcphdr *th = tcp_hdr(skb);
1364
1365 if (!th->syn)
1366 sk = cookie_v4_check(sk, skb);
1367#endif
1368 return sk;
1369}
1370
1371/* The socket must have it's spinlock held when we get
1372 * here, unless it is a TCP_LISTEN socket.
1373 *
1374 * We have a potential double-lock case here, so even when
1375 * doing backlog processing we use the BH locking scheme.
1376 * This is because we cannot sleep with the original spinlock
1377 * held.
1378 */
1379int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
1380{
1381 struct sock *rsk;
1382
1383 if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
1384 struct dst_entry *dst = sk->sk_rx_dst;
1385
1386 sock_rps_save_rxhash(sk, skb);
1387 sk_mark_napi_id(sk, skb);
1388 if (dst) {
1389 if (inet_sk(sk)->rx_dst_ifindex != skb->skb_iif ||
1390 !dst->ops->check(dst, 0)) {
1391 dst_release(dst);
1392 sk->sk_rx_dst = NULL;
1393 }
1394 }
1395 tcp_rcv_established(sk, skb, tcp_hdr(skb), skb->len);
1396 return 0;
1397 }
1398
1399 if (tcp_checksum_complete(skb))
1400 goto csum_err;
1401
1402 if (sk->sk_state == TCP_LISTEN) {
1403 struct sock *nsk = tcp_v4_cookie_check(sk, skb);
1404
1405 if (!nsk)
1406 goto discard;
1407 if (nsk != sk) {
1408 sock_rps_save_rxhash(nsk, skb);
1409 sk_mark_napi_id(nsk, skb);
1410 if (tcp_child_process(sk, nsk, skb)) {
1411 rsk = nsk;
1412 goto reset;
1413 }
1414 return 0;
1415 }
1416 } else
1417 sock_rps_save_rxhash(sk, skb);
1418
1419 if (tcp_rcv_state_process(sk, skb)) {
1420 rsk = sk;
1421 goto reset;
1422 }
1423 return 0;
1424
1425reset:
1426 tcp_v4_send_reset(rsk, skb);
1427discard:
1428 kfree_skb(skb);
1429 /* Be careful here. If this function gets more complicated and
1430 * gcc suffers from register pressure on the x86, sk (in %ebx)
1431 * might be destroyed here. This current version compiles correctly,
1432 * but you have been warned.
1433 */
1434 return 0;
1435
1436csum_err:
1437 TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_CSUMERRORS);
1438 TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_INERRS);
1439 goto discard;
1440}
1441EXPORT_SYMBOL(tcp_v4_do_rcv);
1442
1443void tcp_v4_early_demux(struct sk_buff *skb)
1444{
1445 const struct iphdr *iph;
1446 const struct tcphdr *th;
1447 struct sock *sk;
1448
1449 if (skb->pkt_type != PACKET_HOST)
1450 return;
1451
1452 if (!pskb_may_pull(skb, skb_transport_offset(skb) + sizeof(struct tcphdr)))
1453 return;
1454
1455 iph = ip_hdr(skb);
1456 th = tcp_hdr(skb);
1457
1458 if (th->doff < sizeof(struct tcphdr) / 4)
1459 return;
1460
1461 sk = __inet_lookup_established(dev_net(skb->dev), &tcp_hashinfo,
1462 iph->saddr, th->source,
1463 iph->daddr, ntohs(th->dest),
1464 skb->skb_iif);
1465 if (sk) {
1466 skb->sk = sk;
1467 skb->destructor = sock_edemux;
1468 if (sk_fullsock(sk)) {
1469 struct dst_entry *dst = READ_ONCE(sk->sk_rx_dst);
1470
1471 if (dst)
1472 dst = dst_check(dst, 0);
1473 if (dst &&
1474 inet_sk(sk)->rx_dst_ifindex == skb->skb_iif)
1475 skb_dst_set_noref(skb, dst);
1476 }
1477 }
1478}
1479
1480/* Packet is added to VJ-style prequeue for processing in process
1481 * context, if a reader task is waiting. Apparently, this exciting
1482 * idea (VJ's mail "Re: query about TCP header on tcp-ip" of 07 Sep 93)
1483 * failed somewhere. Latency? Burstiness? Well, at least now we will
1484 * see, why it failed. 8)8) --ANK
1485 *
1486 */
1487bool tcp_prequeue(struct sock *sk, struct sk_buff *skb)
1488{
1489 struct tcp_sock *tp = tcp_sk(sk);
1490
1491 if (sysctl_tcp_low_latency || !tp->ucopy.task)
1492 return false;
1493
1494 if (skb->len <= tcp_hdrlen(skb) &&
1495 skb_queue_len(&tp->ucopy.prequeue) == 0)
1496 return false;
1497
1498 /* Before escaping RCU protected region, we need to take care of skb
1499 * dst. Prequeue is only enabled for established sockets.
1500 * For such sockets, we might need the skb dst only to set sk->sk_rx_dst
1501 * Instead of doing full sk_rx_dst validity here, let's perform
1502 * an optimistic check.
1503 */
1504 if (likely(sk->sk_rx_dst))
1505 skb_dst_drop(skb);
1506 else
1507 skb_dst_force_safe(skb);
1508
1509 __skb_queue_tail(&tp->ucopy.prequeue, skb);
1510 tp->ucopy.memory += skb->truesize;
1511 if (tp->ucopy.memory > sk->sk_rcvbuf) {
1512 struct sk_buff *skb1;
1513
1514 BUG_ON(sock_owned_by_user(sk));
1515
1516 while ((skb1 = __skb_dequeue(&tp->ucopy.prequeue)) != NULL) {
1517 sk_backlog_rcv(sk, skb1);
1518 NET_INC_STATS_BH(sock_net(sk),
1519 LINUX_MIB_TCPPREQUEUEDROPPED);
1520 }
1521
1522 tp->ucopy.memory = 0;
1523 } else if (skb_queue_len(&tp->ucopy.prequeue) == 1) {
1524 wake_up_interruptible_sync_poll(sk_sleep(sk),
1525 POLLIN | POLLRDNORM | POLLRDBAND);
1526 if (!inet_csk_ack_scheduled(sk))
1527 inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK,
1528 (3 * tcp_rto_min(sk)) / 4,
1529 TCP_RTO_MAX);
1530 }
1531 return true;
1532}
1533EXPORT_SYMBOL(tcp_prequeue);
1534
1535/*
1536 * From tcp_input.c
1537 */
1538
1539int tcp_v4_rcv(struct sk_buff *skb)
1540{
1541 const struct iphdr *iph;
1542 const struct tcphdr *th;
1543 struct sock *sk;
1544 int ret;
1545 struct net *net = dev_net(skb->dev);
1546
1547 if (skb->pkt_type != PACKET_HOST)
1548 goto discard_it;
1549
1550 /* Count it even if it's bad */
1551 TCP_INC_STATS_BH(net, TCP_MIB_INSEGS);
1552
1553 if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
1554 goto discard_it;
1555
1556 th = tcp_hdr(skb);
1557
1558 if (th->doff < sizeof(struct tcphdr) / 4)
1559 goto bad_packet;
1560 if (!pskb_may_pull(skb, th->doff * 4))
1561 goto discard_it;
1562
1563 /* An explanation is required here, I think.
1564 * Packet length and doff are validated by header prediction,
1565 * provided case of th->doff==0 is eliminated.
1566 * So, we defer the checks. */
1567
1568 if (skb_checksum_init(skb, IPPROTO_TCP, inet_compute_pseudo))
1569 goto csum_error;
1570
1571 th = tcp_hdr(skb);
1572 iph = ip_hdr(skb);
1573 /* This is tricky : We move IPCB at its correct location into TCP_SKB_CB()
1574 * barrier() makes sure compiler wont play fool^Waliasing games.
1575 */
1576 memmove(&TCP_SKB_CB(skb)->header.h4, IPCB(skb),
1577 sizeof(struct inet_skb_parm));
1578 barrier();
1579
1580 TCP_SKB_CB(skb)->seq = ntohl(th->seq);
1581 TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
1582 skb->len - th->doff * 4);
1583 TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
1584 TCP_SKB_CB(skb)->tcp_flags = tcp_flag_byte(th);
1585 TCP_SKB_CB(skb)->tcp_tw_isn = 0;
1586 TCP_SKB_CB(skb)->ip_dsfield = ipv4_get_dsfield(iph);
1587 TCP_SKB_CB(skb)->sacked = 0;
1588
1589lookup:
1590 sk = __inet_lookup_skb(&tcp_hashinfo, skb, __tcp_hdrlen(th), th->source,
1591 th->dest);
1592 if (!sk)
1593 goto no_tcp_socket;
1594
1595process:
1596 if (sk->sk_state == TCP_TIME_WAIT)
1597 goto do_time_wait;
1598
1599 if (sk->sk_state == TCP_NEW_SYN_RECV) {
1600 struct request_sock *req = inet_reqsk(sk);
1601 struct sock *nsk;
1602
1603 sk = req->rsk_listener;
1604 if (unlikely(tcp_v4_inbound_md5_hash(sk, skb))) {
1605 reqsk_put(req);
1606 goto discard_it;
1607 }
1608 if (unlikely(sk->sk_state != TCP_LISTEN)) {
1609 inet_csk_reqsk_queue_drop_and_put(sk, req);
1610 goto lookup;
1611 }
1612 sock_hold(sk);
1613 nsk = tcp_check_req(sk, skb, req, false);
1614 if (!nsk) {
1615 reqsk_put(req);
1616 goto discard_and_relse;
1617 }
1618 if (nsk == sk) {
1619 reqsk_put(req);
1620 } else if (tcp_child_process(sk, nsk, skb)) {
1621 tcp_v4_send_reset(nsk, skb);
1622 goto discard_and_relse;
1623 } else {
1624 sock_put(sk);
1625 return 0;
1626 }
1627 }
1628 if (unlikely(iph->ttl < inet_sk(sk)->min_ttl)) {
1629 NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP);
1630 goto discard_and_relse;
1631 }
1632
1633 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
1634 goto discard_and_relse;
1635
1636 if (tcp_v4_inbound_md5_hash(sk, skb))
1637 goto discard_and_relse;
1638
1639 nf_reset(skb);
1640
1641 if (sk_filter(sk, skb))
1642 goto discard_and_relse;
1643
1644 skb->dev = NULL;
1645
1646 if (sk->sk_state == TCP_LISTEN) {
1647 ret = tcp_v4_do_rcv(sk, skb);
1648 goto put_and_return;
1649 }
1650
1651 sk_incoming_cpu_update(sk);
1652
1653 bh_lock_sock_nested(sk);
1654 tcp_segs_in(tcp_sk(sk), skb);
1655 ret = 0;
1656 if (!sock_owned_by_user(sk)) {
1657 if (!tcp_prequeue(sk, skb))
1658 ret = tcp_v4_do_rcv(sk, skb);
1659 } else if (unlikely(sk_add_backlog(sk, skb,
1660 sk->sk_rcvbuf + sk->sk_sndbuf))) {
1661 bh_unlock_sock(sk);
1662 NET_INC_STATS_BH(net, LINUX_MIB_TCPBACKLOGDROP);
1663 goto discard_and_relse;
1664 }
1665 bh_unlock_sock(sk);
1666
1667put_and_return:
1668 sock_put(sk);
1669
1670 return ret;
1671
1672no_tcp_socket:
1673 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
1674 goto discard_it;
1675
1676 if (tcp_checksum_complete(skb)) {
1677csum_error:
1678 TCP_INC_STATS_BH(net, TCP_MIB_CSUMERRORS);
1679bad_packet:
1680 TCP_INC_STATS_BH(net, TCP_MIB_INERRS);
1681 } else {
1682 tcp_v4_send_reset(NULL, skb);
1683 }
1684
1685discard_it:
1686 /* Discard frame. */
1687 kfree_skb(skb);
1688 return 0;
1689
1690discard_and_relse:
1691 sock_put(sk);
1692 goto discard_it;
1693
1694do_time_wait:
1695 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
1696 inet_twsk_put(inet_twsk(sk));
1697 goto discard_it;
1698 }
1699
1700 if (tcp_checksum_complete(skb)) {
1701 inet_twsk_put(inet_twsk(sk));
1702 goto csum_error;
1703 }
1704 switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) {
1705 case TCP_TW_SYN: {
1706 struct sock *sk2 = inet_lookup_listener(dev_net(skb->dev),
1707 &tcp_hashinfo, skb,
1708 __tcp_hdrlen(th),
1709 iph->saddr, th->source,
1710 iph->daddr, th->dest,
1711 inet_iif(skb));
1712 if (sk2) {
1713 inet_twsk_deschedule_put(inet_twsk(sk));
1714 sk = sk2;
1715 goto process;
1716 }
1717 /* Fall through to ACK */
1718 }
1719 case TCP_TW_ACK:
1720 tcp_v4_timewait_ack(sk, skb);
1721 break;
1722 case TCP_TW_RST:
1723 tcp_v4_send_reset(sk, skb);
1724 inet_twsk_deschedule_put(inet_twsk(sk));
1725 goto discard_it;
1726 case TCP_TW_SUCCESS:;
1727 }
1728 goto discard_it;
1729}
1730
1731static struct timewait_sock_ops tcp_timewait_sock_ops = {
1732 .twsk_obj_size = sizeof(struct tcp_timewait_sock),
1733 .twsk_unique = tcp_twsk_unique,
1734 .twsk_destructor= tcp_twsk_destructor,
1735};
1736
1737void inet_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb)
1738{
1739 struct dst_entry *dst = skb_dst(skb);
1740
1741 if (dst && dst_hold_safe(dst)) {
1742 sk->sk_rx_dst = dst;
1743 inet_sk(sk)->rx_dst_ifindex = skb->skb_iif;
1744 }
1745}
1746EXPORT_SYMBOL(inet_sk_rx_dst_set);
1747
1748const struct inet_connection_sock_af_ops ipv4_specific = {
1749 .queue_xmit = ip_queue_xmit,
1750 .send_check = tcp_v4_send_check,
1751 .rebuild_header = inet_sk_rebuild_header,
1752 .sk_rx_dst_set = inet_sk_rx_dst_set,
1753 .conn_request = tcp_v4_conn_request,
1754 .syn_recv_sock = tcp_v4_syn_recv_sock,
1755 .net_header_len = sizeof(struct iphdr),
1756 .setsockopt = ip_setsockopt,
1757 .getsockopt = ip_getsockopt,
1758 .addr2sockaddr = inet_csk_addr2sockaddr,
1759 .sockaddr_len = sizeof(struct sockaddr_in),
1760 .bind_conflict = inet_csk_bind_conflict,
1761#ifdef CONFIG_COMPAT
1762 .compat_setsockopt = compat_ip_setsockopt,
1763 .compat_getsockopt = compat_ip_getsockopt,
1764#endif
1765 .mtu_reduced = tcp_v4_mtu_reduced,
1766};
1767EXPORT_SYMBOL(ipv4_specific);
1768
1769#ifdef CONFIG_TCP_MD5SIG
1770static const struct tcp_sock_af_ops tcp_sock_ipv4_specific = {
1771 .md5_lookup = tcp_v4_md5_lookup,
1772 .calc_md5_hash = tcp_v4_md5_hash_skb,
1773 .md5_parse = tcp_v4_parse_md5_keys,
1774};
1775#endif
1776
1777/* NOTE: A lot of things set to zero explicitly by call to
1778 * sk_alloc() so need not be done here.
1779 */
1780static int tcp_v4_init_sock(struct sock *sk)
1781{
1782 struct inet_connection_sock *icsk = inet_csk(sk);
1783
1784 tcp_init_sock(sk);
1785
1786 icsk->icsk_af_ops = &ipv4_specific;
1787
1788#ifdef CONFIG_TCP_MD5SIG
1789 tcp_sk(sk)->af_specific = &tcp_sock_ipv4_specific;
1790#endif
1791
1792 return 0;
1793}
1794
1795void tcp_v4_destroy_sock(struct sock *sk)
1796{
1797 struct tcp_sock *tp = tcp_sk(sk);
1798
1799 tcp_clear_xmit_timers(sk);
1800
1801 tcp_cleanup_congestion_control(sk);
1802
1803 /* Cleanup up the write buffer. */
1804 tcp_write_queue_purge(sk);
1805
1806 /* Cleans up our, hopefully empty, out_of_order_queue. */
1807 __skb_queue_purge(&tp->out_of_order_queue);
1808
1809#ifdef CONFIG_TCP_MD5SIG
1810 /* Clean up the MD5 key list, if any */
1811 if (tp->md5sig_info) {
1812 tcp_clear_md5_list(sk);
1813 kfree_rcu(tp->md5sig_info, rcu);
1814 tp->md5sig_info = NULL;
1815 }
1816#endif
1817
1818 /* Clean prequeue, it must be empty really */
1819 __skb_queue_purge(&tp->ucopy.prequeue);
1820
1821 /* Clean up a referenced TCP bind bucket. */
1822 if (inet_csk(sk)->icsk_bind_hash)
1823 inet_put_port(sk);
1824
1825 BUG_ON(tp->fastopen_rsk);
1826
1827 /* If socket is aborted during connect operation */
1828 tcp_free_fastopen_req(tp);
1829 tcp_saved_syn_free(tp);
1830
1831 sk_sockets_allocated_dec(sk);
1832
1833 if (mem_cgroup_sockets_enabled && sk->sk_memcg)
1834 sock_release_memcg(sk);
1835}
1836EXPORT_SYMBOL(tcp_v4_destroy_sock);
1837
1838#ifdef CONFIG_PROC_FS
1839/* Proc filesystem TCP sock list dumping. */
1840
1841/*
1842 * Get next listener socket follow cur. If cur is NULL, get first socket
1843 * starting from bucket given in st->bucket; when st->bucket is zero the
1844 * very first socket in the hash table is returned.
1845 */
1846static void *listening_get_next(struct seq_file *seq, void *cur)
1847{
1848 struct inet_connection_sock *icsk;
1849 struct hlist_nulls_node *node;
1850 struct sock *sk = cur;
1851 struct inet_listen_hashbucket *ilb;
1852 struct tcp_iter_state *st = seq->private;
1853 struct net *net = seq_file_net(seq);
1854
1855 if (!sk) {
1856 ilb = &tcp_hashinfo.listening_hash[st->bucket];
1857 spin_lock_bh(&ilb->lock);
1858 sk = sk_nulls_head(&ilb->head);
1859 st->offset = 0;
1860 goto get_sk;
1861 }
1862 ilb = &tcp_hashinfo.listening_hash[st->bucket];
1863 ++st->num;
1864 ++st->offset;
1865
1866 sk = sk_nulls_next(sk);
1867get_sk:
1868 sk_nulls_for_each_from(sk, node) {
1869 if (!net_eq(sock_net(sk), net))
1870 continue;
1871 if (sk->sk_family == st->family) {
1872 cur = sk;
1873 goto out;
1874 }
1875 icsk = inet_csk(sk);
1876 }
1877 spin_unlock_bh(&ilb->lock);
1878 st->offset = 0;
1879 if (++st->bucket < INET_LHTABLE_SIZE) {
1880 ilb = &tcp_hashinfo.listening_hash[st->bucket];
1881 spin_lock_bh(&ilb->lock);
1882 sk = sk_nulls_head(&ilb->head);
1883 goto get_sk;
1884 }
1885 cur = NULL;
1886out:
1887 return cur;
1888}
1889
1890static void *listening_get_idx(struct seq_file *seq, loff_t *pos)
1891{
1892 struct tcp_iter_state *st = seq->private;
1893 void *rc;
1894
1895 st->bucket = 0;
1896 st->offset = 0;
1897 rc = listening_get_next(seq, NULL);
1898
1899 while (rc && *pos) {
1900 rc = listening_get_next(seq, rc);
1901 --*pos;
1902 }
1903 return rc;
1904}
1905
1906static inline bool empty_bucket(const struct tcp_iter_state *st)
1907{
1908 return hlist_nulls_empty(&tcp_hashinfo.ehash[st->bucket].chain);
1909}
1910
1911/*
1912 * Get first established socket starting from bucket given in st->bucket.
1913 * If st->bucket is zero, the very first socket in the hash is returned.
1914 */
1915static void *established_get_first(struct seq_file *seq)
1916{
1917 struct tcp_iter_state *st = seq->private;
1918 struct net *net = seq_file_net(seq);
1919 void *rc = NULL;
1920
1921 st->offset = 0;
1922 for (; st->bucket <= tcp_hashinfo.ehash_mask; ++st->bucket) {
1923 struct sock *sk;
1924 struct hlist_nulls_node *node;
1925 spinlock_t *lock = inet_ehash_lockp(&tcp_hashinfo, st->bucket);
1926
1927 /* Lockless fast path for the common case of empty buckets */
1928 if (empty_bucket(st))
1929 continue;
1930
1931 spin_lock_bh(lock);
1932 sk_nulls_for_each(sk, node, &tcp_hashinfo.ehash[st->bucket].chain) {
1933 if (sk->sk_family != st->family ||
1934 !net_eq(sock_net(sk), net)) {
1935 continue;
1936 }
1937 rc = sk;
1938 goto out;
1939 }
1940 spin_unlock_bh(lock);
1941 }
1942out:
1943 return rc;
1944}
1945
1946static void *established_get_next(struct seq_file *seq, void *cur)
1947{
1948 struct sock *sk = cur;
1949 struct hlist_nulls_node *node;
1950 struct tcp_iter_state *st = seq->private;
1951 struct net *net = seq_file_net(seq);
1952
1953 ++st->num;
1954 ++st->offset;
1955
1956 sk = sk_nulls_next(sk);
1957
1958 sk_nulls_for_each_from(sk, node) {
1959 if (sk->sk_family == st->family && net_eq(sock_net(sk), net))
1960 return sk;
1961 }
1962
1963 spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
1964 ++st->bucket;
1965 return established_get_first(seq);
1966}
1967
1968static void *established_get_idx(struct seq_file *seq, loff_t pos)
1969{
1970 struct tcp_iter_state *st = seq->private;
1971 void *rc;
1972
1973 st->bucket = 0;
1974 rc = established_get_first(seq);
1975
1976 while (rc && pos) {
1977 rc = established_get_next(seq, rc);
1978 --pos;
1979 }
1980 return rc;
1981}
1982
1983static void *tcp_get_idx(struct seq_file *seq, loff_t pos)
1984{
1985 void *rc;
1986 struct tcp_iter_state *st = seq->private;
1987
1988 st->state = TCP_SEQ_STATE_LISTENING;
1989 rc = listening_get_idx(seq, &pos);
1990
1991 if (!rc) {
1992 st->state = TCP_SEQ_STATE_ESTABLISHED;
1993 rc = established_get_idx(seq, pos);
1994 }
1995
1996 return rc;
1997}
1998
1999static void *tcp_seek_last_pos(struct seq_file *seq)
2000{
2001 struct tcp_iter_state *st = seq->private;
2002 int offset = st->offset;
2003 int orig_num = st->num;
2004 void *rc = NULL;
2005
2006 switch (st->state) {
2007 case TCP_SEQ_STATE_LISTENING:
2008 if (st->bucket >= INET_LHTABLE_SIZE)
2009 break;
2010 st->state = TCP_SEQ_STATE_LISTENING;
2011 rc = listening_get_next(seq, NULL);
2012 while (offset-- && rc)
2013 rc = listening_get_next(seq, rc);
2014 if (rc)
2015 break;
2016 st->bucket = 0;
2017 st->state = TCP_SEQ_STATE_ESTABLISHED;
2018 /* Fallthrough */
2019 case TCP_SEQ_STATE_ESTABLISHED:
2020 if (st->bucket > tcp_hashinfo.ehash_mask)
2021 break;
2022 rc = established_get_first(seq);
2023 while (offset-- && rc)
2024 rc = established_get_next(seq, rc);
2025 }
2026
2027 st->num = orig_num;
2028
2029 return rc;
2030}
2031
2032static void *tcp_seq_start(struct seq_file *seq, loff_t *pos)
2033{
2034 struct tcp_iter_state *st = seq->private;
2035 void *rc;
2036
2037 if (*pos && *pos == st->last_pos) {
2038 rc = tcp_seek_last_pos(seq);
2039 if (rc)
2040 goto out;
2041 }
2042
2043 st->state = TCP_SEQ_STATE_LISTENING;
2044 st->num = 0;
2045 st->bucket = 0;
2046 st->offset = 0;
2047 rc = *pos ? tcp_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
2048
2049out:
2050 st->last_pos = *pos;
2051 return rc;
2052}
2053
2054static void *tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2055{
2056 struct tcp_iter_state *st = seq->private;
2057 void *rc = NULL;
2058
2059 if (v == SEQ_START_TOKEN) {
2060 rc = tcp_get_idx(seq, 0);
2061 goto out;
2062 }
2063
2064 switch (st->state) {
2065 case TCP_SEQ_STATE_LISTENING:
2066 rc = listening_get_next(seq, v);
2067 if (!rc) {
2068 st->state = TCP_SEQ_STATE_ESTABLISHED;
2069 st->bucket = 0;
2070 st->offset = 0;
2071 rc = established_get_first(seq);
2072 }
2073 break;
2074 case TCP_SEQ_STATE_ESTABLISHED:
2075 rc = established_get_next(seq, v);
2076 break;
2077 }
2078out:
2079 ++*pos;
2080 st->last_pos = *pos;
2081 return rc;
2082}
2083
2084static void tcp_seq_stop(struct seq_file *seq, void *v)
2085{
2086 struct tcp_iter_state *st = seq->private;
2087
2088 switch (st->state) {
2089 case TCP_SEQ_STATE_LISTENING:
2090 if (v != SEQ_START_TOKEN)
2091 spin_unlock_bh(&tcp_hashinfo.listening_hash[st->bucket].lock);
2092 break;
2093 case TCP_SEQ_STATE_ESTABLISHED:
2094 if (v)
2095 spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
2096 break;
2097 }
2098}
2099
2100int tcp_seq_open(struct inode *inode, struct file *file)
2101{
2102 struct tcp_seq_afinfo *afinfo = PDE_DATA(inode);
2103 struct tcp_iter_state *s;
2104 int err;
2105
2106 err = seq_open_net(inode, file, &afinfo->seq_ops,
2107 sizeof(struct tcp_iter_state));
2108 if (err < 0)
2109 return err;
2110
2111 s = ((struct seq_file *)file->private_data)->private;
2112 s->family = afinfo->family;
2113 s->last_pos = 0;
2114 return 0;
2115}
2116EXPORT_SYMBOL(tcp_seq_open);
2117
2118int tcp_proc_register(struct net *net, struct tcp_seq_afinfo *afinfo)
2119{
2120 int rc = 0;
2121 struct proc_dir_entry *p;
2122
2123 afinfo->seq_ops.start = tcp_seq_start;
2124 afinfo->seq_ops.next = tcp_seq_next;
2125 afinfo->seq_ops.stop = tcp_seq_stop;
2126
2127 p = proc_create_data(afinfo->name, S_IRUGO, net->proc_net,
2128 afinfo->seq_fops, afinfo);
2129 if (!p)
2130 rc = -ENOMEM;
2131 return rc;
2132}
2133EXPORT_SYMBOL(tcp_proc_register);
2134
2135void tcp_proc_unregister(struct net *net, struct tcp_seq_afinfo *afinfo)
2136{
2137 remove_proc_entry(afinfo->name, net->proc_net);
2138}
2139EXPORT_SYMBOL(tcp_proc_unregister);
2140
2141static void get_openreq4(const struct request_sock *req,
2142 struct seq_file *f, int i)
2143{
2144 const struct inet_request_sock *ireq = inet_rsk(req);
2145 long delta = req->rsk_timer.expires - jiffies;
2146
2147 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2148 " %02X %08X:%08X %02X:%08lX %08X %5u %8d %u %d %pK",
2149 i,
2150 ireq->ir_loc_addr,
2151 ireq->ir_num,
2152 ireq->ir_rmt_addr,
2153 ntohs(ireq->ir_rmt_port),
2154 TCP_SYN_RECV,
2155 0, 0, /* could print option size, but that is af dependent. */
2156 1, /* timers active (only the expire timer) */
2157 jiffies_delta_to_clock_t(delta),
2158 req->num_timeout,
2159 from_kuid_munged(seq_user_ns(f),
2160 sock_i_uid(req->rsk_listener)),
2161 0, /* non standard timer */
2162 0, /* open_requests have no inode */
2163 0,
2164 req);
2165}
2166
2167static void get_tcp4_sock(struct sock *sk, struct seq_file *f, int i)
2168{
2169 int timer_active;
2170 unsigned long timer_expires;
2171 const struct tcp_sock *tp = tcp_sk(sk);
2172 const struct inet_connection_sock *icsk = inet_csk(sk);
2173 const struct inet_sock *inet = inet_sk(sk);
2174 const struct fastopen_queue *fastopenq = &icsk->icsk_accept_queue.fastopenq;
2175 __be32 dest = inet->inet_daddr;
2176 __be32 src = inet->inet_rcv_saddr;
2177 __u16 destp = ntohs(inet->inet_dport);
2178 __u16 srcp = ntohs(inet->inet_sport);
2179 int rx_queue;
2180 int state;
2181
2182 if (icsk->icsk_pending == ICSK_TIME_RETRANS ||
2183 icsk->icsk_pending == ICSK_TIME_EARLY_RETRANS ||
2184 icsk->icsk_pending == ICSK_TIME_LOSS_PROBE) {
2185 timer_active = 1;
2186 timer_expires = icsk->icsk_timeout;
2187 } else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
2188 timer_active = 4;
2189 timer_expires = icsk->icsk_timeout;
2190 } else if (timer_pending(&sk->sk_timer)) {
2191 timer_active = 2;
2192 timer_expires = sk->sk_timer.expires;
2193 } else {
2194 timer_active = 0;
2195 timer_expires = jiffies;
2196 }
2197
2198 state = sk_state_load(sk);
2199 if (state == TCP_LISTEN)
2200 rx_queue = sk->sk_ack_backlog;
2201 else
2202 /* Because we don't lock the socket,
2203 * we might find a transient negative value.
2204 */
2205 rx_queue = max_t(int, tp->rcv_nxt - tp->copied_seq, 0);
2206
2207 seq_printf(f, "%4d: %08X:%04X %08X:%04X %02X %08X:%08X %02X:%08lX "
2208 "%08X %5u %8d %lu %d %pK %lu %lu %u %u %d",
2209 i, src, srcp, dest, destp, state,
2210 tp->write_seq - tp->snd_una,
2211 rx_queue,
2212 timer_active,
2213 jiffies_delta_to_clock_t(timer_expires - jiffies),
2214 icsk->icsk_retransmits,
2215 from_kuid_munged(seq_user_ns(f), sock_i_uid(sk)),
2216 icsk->icsk_probes_out,
2217 sock_i_ino(sk),
2218 atomic_read(&sk->sk_refcnt), sk,
2219 jiffies_to_clock_t(icsk->icsk_rto),
2220 jiffies_to_clock_t(icsk->icsk_ack.ato),
2221 (icsk->icsk_ack.quick << 1) | icsk->icsk_ack.pingpong,
2222 tp->snd_cwnd,
2223 state == TCP_LISTEN ?
2224 fastopenq->max_qlen :
2225 (tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh));
2226}
2227
2228static void get_timewait4_sock(const struct inet_timewait_sock *tw,
2229 struct seq_file *f, int i)
2230{
2231 long delta = tw->tw_timer.expires - jiffies;
2232 __be32 dest, src;
2233 __u16 destp, srcp;
2234
2235 dest = tw->tw_daddr;
2236 src = tw->tw_rcv_saddr;
2237 destp = ntohs(tw->tw_dport);
2238 srcp = ntohs(tw->tw_sport);
2239
2240 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2241 " %02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK",
2242 i, src, srcp, dest, destp, tw->tw_substate, 0, 0,
2243 3, jiffies_delta_to_clock_t(delta), 0, 0, 0, 0,
2244 atomic_read(&tw->tw_refcnt), tw);
2245}
2246
2247#define TMPSZ 150
2248
2249static int tcp4_seq_show(struct seq_file *seq, void *v)
2250{
2251 struct tcp_iter_state *st;
2252 struct sock *sk = v;
2253
2254 seq_setwidth(seq, TMPSZ - 1);
2255 if (v == SEQ_START_TOKEN) {
2256 seq_puts(seq, " sl local_address rem_address st tx_queue "
2257 "rx_queue tr tm->when retrnsmt uid timeout "
2258 "inode");
2259 goto out;
2260 }
2261 st = seq->private;
2262
2263 if (sk->sk_state == TCP_TIME_WAIT)
2264 get_timewait4_sock(v, seq, st->num);
2265 else if (sk->sk_state == TCP_NEW_SYN_RECV)
2266 get_openreq4(v, seq, st->num);
2267 else
2268 get_tcp4_sock(v, seq, st->num);
2269out:
2270 seq_pad(seq, '\n');
2271 return 0;
2272}
2273
2274static const struct file_operations tcp_afinfo_seq_fops = {
2275 .owner = THIS_MODULE,
2276 .open = tcp_seq_open,
2277 .read = seq_read,
2278 .llseek = seq_lseek,
2279 .release = seq_release_net
2280};
2281
2282static struct tcp_seq_afinfo tcp4_seq_afinfo = {
2283 .name = "tcp",
2284 .family = AF_INET,
2285 .seq_fops = &tcp_afinfo_seq_fops,
2286 .seq_ops = {
2287 .show = tcp4_seq_show,
2288 },
2289};
2290
2291static int __net_init tcp4_proc_init_net(struct net *net)
2292{
2293 return tcp_proc_register(net, &tcp4_seq_afinfo);
2294}
2295
2296static void __net_exit tcp4_proc_exit_net(struct net *net)
2297{
2298 tcp_proc_unregister(net, &tcp4_seq_afinfo);
2299}
2300
2301static struct pernet_operations tcp4_net_ops = {
2302 .init = tcp4_proc_init_net,
2303 .exit = tcp4_proc_exit_net,
2304};
2305
2306int __init tcp4_proc_init(void)
2307{
2308 return register_pernet_subsys(&tcp4_net_ops);
2309}
2310
2311void tcp4_proc_exit(void)
2312{
2313 unregister_pernet_subsys(&tcp4_net_ops);
2314}
2315#endif /* CONFIG_PROC_FS */
2316
2317struct proto tcp_prot = {
2318 .name = "TCP",
2319 .owner = THIS_MODULE,
2320 .close = tcp_close,
2321 .connect = tcp_v4_connect,
2322 .disconnect = tcp_disconnect,
2323 .accept = inet_csk_accept,
2324 .ioctl = tcp_ioctl,
2325 .init = tcp_v4_init_sock,
2326 .destroy = tcp_v4_destroy_sock,
2327 .shutdown = tcp_shutdown,
2328 .setsockopt = tcp_setsockopt,
2329 .getsockopt = tcp_getsockopt,
2330 .recvmsg = tcp_recvmsg,
2331 .sendmsg = tcp_sendmsg,
2332 .sendpage = tcp_sendpage,
2333 .backlog_rcv = tcp_v4_do_rcv,
2334 .release_cb = tcp_release_cb,
2335 .hash = inet_hash,
2336 .unhash = inet_unhash,
2337 .get_port = inet_csk_get_port,
2338 .enter_memory_pressure = tcp_enter_memory_pressure,
2339 .stream_memory_free = tcp_stream_memory_free,
2340 .sockets_allocated = &tcp_sockets_allocated,
2341 .orphan_count = &tcp_orphan_count,
2342 .memory_allocated = &tcp_memory_allocated,
2343 .memory_pressure = &tcp_memory_pressure,
2344 .sysctl_mem = sysctl_tcp_mem,
2345 .sysctl_wmem = sysctl_tcp_wmem,
2346 .sysctl_rmem = sysctl_tcp_rmem,
2347 .max_header = MAX_TCP_HEADER,
2348 .obj_size = sizeof(struct tcp_sock),
2349 .slab_flags = SLAB_DESTROY_BY_RCU,
2350 .twsk_prot = &tcp_timewait_sock_ops,
2351 .rsk_prot = &tcp_request_sock_ops,
2352 .h.hashinfo = &tcp_hashinfo,
2353 .no_autobind = true,
2354#ifdef CONFIG_COMPAT
2355 .compat_setsockopt = compat_tcp_setsockopt,
2356 .compat_getsockopt = compat_tcp_getsockopt,
2357#endif
2358 .diag_destroy = tcp_abort,
2359};
2360EXPORT_SYMBOL(tcp_prot);
2361
2362static void __net_exit tcp_sk_exit(struct net *net)
2363{
2364 int cpu;
2365
2366 for_each_possible_cpu(cpu)
2367 inet_ctl_sock_destroy(*per_cpu_ptr(net->ipv4.tcp_sk, cpu));
2368 free_percpu(net->ipv4.tcp_sk);
2369}
2370
2371static int __net_init tcp_sk_init(struct net *net)
2372{
2373 int res, cpu;
2374
2375 net->ipv4.tcp_sk = alloc_percpu(struct sock *);
2376 if (!net->ipv4.tcp_sk)
2377 return -ENOMEM;
2378
2379 for_each_possible_cpu(cpu) {
2380 struct sock *sk;
2381
2382 res = inet_ctl_sock_create(&sk, PF_INET, SOCK_RAW,
2383 IPPROTO_TCP, net);
2384 if (res)
2385 goto fail;
2386 *per_cpu_ptr(net->ipv4.tcp_sk, cpu) = sk;
2387 }
2388
2389 net->ipv4.sysctl_tcp_ecn = 2;
2390 net->ipv4.sysctl_tcp_ecn_fallback = 1;
2391
2392 net->ipv4.sysctl_tcp_base_mss = TCP_BASE_MSS;
2393 net->ipv4.sysctl_tcp_probe_threshold = TCP_PROBE_THRESHOLD;
2394 net->ipv4.sysctl_tcp_probe_interval = TCP_PROBE_INTERVAL;
2395
2396 net->ipv4.sysctl_tcp_keepalive_time = TCP_KEEPALIVE_TIME;
2397 net->ipv4.sysctl_tcp_keepalive_probes = TCP_KEEPALIVE_PROBES;
2398 net->ipv4.sysctl_tcp_keepalive_intvl = TCP_KEEPALIVE_INTVL;
2399
2400 net->ipv4.sysctl_tcp_syn_retries = TCP_SYN_RETRIES;
2401 net->ipv4.sysctl_tcp_synack_retries = TCP_SYNACK_RETRIES;
2402 net->ipv4.sysctl_tcp_syncookies = 1;
2403 net->ipv4.sysctl_tcp_reordering = TCP_FASTRETRANS_THRESH;
2404 net->ipv4.sysctl_tcp_retries1 = TCP_RETR1;
2405 net->ipv4.sysctl_tcp_retries2 = TCP_RETR2;
2406 net->ipv4.sysctl_tcp_orphan_retries = 0;
2407 net->ipv4.sysctl_tcp_fin_timeout = TCP_FIN_TIMEOUT;
2408 net->ipv4.sysctl_tcp_notsent_lowat = UINT_MAX;
2409
2410 return 0;
2411fail:
2412 tcp_sk_exit(net);
2413
2414 return res;
2415}
2416
2417static void __net_exit tcp_sk_exit_batch(struct list_head *net_exit_list)
2418{
2419 inet_twsk_purge(&tcp_hashinfo, &tcp_death_row, AF_INET);
2420}
2421
2422static struct pernet_operations __net_initdata tcp_sk_ops = {
2423 .init = tcp_sk_init,
2424 .exit = tcp_sk_exit,
2425 .exit_batch = tcp_sk_exit_batch,
2426};
2427
2428void __init tcp_v4_init(void)
2429{
2430 inet_hashinfo_init(&tcp_hashinfo);
2431 if (register_pernet_subsys(&tcp_sk_ops))
2432 panic("Failed to create the TCP control socket.\n");
2433}