Loading...
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * INET An implementation of the TCP/IP protocol suite for the LINUX
4 * operating system. INET is implemented using the BSD Socket
5 * interface as the means of communication with the user level.
6 *
7 * Implementation of the Transmission Control Protocol(TCP).
8 *
9 * IPv4 specific functions
10 *
11 * code split from:
12 * linux/ipv4/tcp.c
13 * linux/ipv4/tcp_input.c
14 * linux/ipv4/tcp_output.c
15 *
16 * See tcp.c for author information
17 */
18
19/*
20 * Changes:
21 * David S. Miller : New socket lookup architecture.
22 * This code is dedicated to John Dyson.
23 * David S. Miller : Change semantics of established hash,
24 * half is devoted to TIME_WAIT sockets
25 * and the rest go in the other half.
26 * Andi Kleen : Add support for syncookies and fixed
27 * some bugs: ip options weren't passed to
28 * the TCP layer, missed a check for an
29 * ACK bit.
30 * Andi Kleen : Implemented fast path mtu discovery.
31 * Fixed many serious bugs in the
32 * request_sock handling and moved
33 * most of it into the af independent code.
34 * Added tail drop and some other bugfixes.
35 * Added new listen semantics.
36 * Mike McLagan : Routing by source
37 * Juan Jose Ciarlante: ip_dynaddr bits
38 * Andi Kleen: various fixes.
39 * Vitaly E. Lavrov : Transparent proxy revived after year
40 * coma.
41 * Andi Kleen : Fix new listen.
42 * Andi Kleen : Fix accept error reporting.
43 * YOSHIFUJI Hideaki @USAGI and: Support IPV6_V6ONLY socket option, which
44 * Alexey Kuznetsov allow both IPv4 and IPv6 sockets to bind
45 * a single port at the same time.
46 */
47
48#define pr_fmt(fmt) "TCP: " fmt
49
50#include <linux/bottom_half.h>
51#include <linux/types.h>
52#include <linux/fcntl.h>
53#include <linux/module.h>
54#include <linux/random.h>
55#include <linux/cache.h>
56#include <linux/jhash.h>
57#include <linux/init.h>
58#include <linux/times.h>
59#include <linux/slab.h>
60
61#include <net/net_namespace.h>
62#include <net/icmp.h>
63#include <net/inet_hashtables.h>
64#include <net/tcp.h>
65#include <net/transp_v6.h>
66#include <net/ipv6.h>
67#include <net/inet_common.h>
68#include <net/timewait_sock.h>
69#include <net/xfrm.h>
70#include <net/secure_seq.h>
71#include <net/busy_poll.h>
72
73#include <linux/inet.h>
74#include <linux/ipv6.h>
75#include <linux/stddef.h>
76#include <linux/proc_fs.h>
77#include <linux/seq_file.h>
78#include <linux/inetdevice.h>
79#include <linux/btf_ids.h>
80
81#include <crypto/hash.h>
82#include <linux/scatterlist.h>
83
84#include <trace/events/tcp.h>
85
86#ifdef CONFIG_TCP_MD5SIG
87static int tcp_v4_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key,
88 __be32 daddr, __be32 saddr, const struct tcphdr *th);
89#endif
90
91struct inet_hashinfo tcp_hashinfo;
92EXPORT_SYMBOL(tcp_hashinfo);
93
94static u32 tcp_v4_init_seq(const struct sk_buff *skb)
95{
96 return secure_tcp_seq(ip_hdr(skb)->daddr,
97 ip_hdr(skb)->saddr,
98 tcp_hdr(skb)->dest,
99 tcp_hdr(skb)->source);
100}
101
102static u32 tcp_v4_init_ts_off(const struct net *net, const struct sk_buff *skb)
103{
104 return secure_tcp_ts_off(net, ip_hdr(skb)->daddr, ip_hdr(skb)->saddr);
105}
106
107int tcp_twsk_unique(struct sock *sk, struct sock *sktw, void *twp)
108{
109 const struct inet_timewait_sock *tw = inet_twsk(sktw);
110 const struct tcp_timewait_sock *tcptw = tcp_twsk(sktw);
111 struct tcp_sock *tp = tcp_sk(sk);
112 int reuse = sock_net(sk)->ipv4.sysctl_tcp_tw_reuse;
113
114 if (reuse == 2) {
115 /* Still does not detect *everything* that goes through
116 * lo, since we require a loopback src or dst address
117 * or direct binding to 'lo' interface.
118 */
119 bool loopback = false;
120 if (tw->tw_bound_dev_if == LOOPBACK_IFINDEX)
121 loopback = true;
122#if IS_ENABLED(CONFIG_IPV6)
123 if (tw->tw_family == AF_INET6) {
124 if (ipv6_addr_loopback(&tw->tw_v6_daddr) ||
125 ipv6_addr_v4mapped_loopback(&tw->tw_v6_daddr) ||
126 ipv6_addr_loopback(&tw->tw_v6_rcv_saddr) ||
127 ipv6_addr_v4mapped_loopback(&tw->tw_v6_rcv_saddr))
128 loopback = true;
129 } else
130#endif
131 {
132 if (ipv4_is_loopback(tw->tw_daddr) ||
133 ipv4_is_loopback(tw->tw_rcv_saddr))
134 loopback = true;
135 }
136 if (!loopback)
137 reuse = 0;
138 }
139
140 /* With PAWS, it is safe from the viewpoint
141 of data integrity. Even without PAWS it is safe provided sequence
142 spaces do not overlap i.e. at data rates <= 80Mbit/sec.
143
144 Actually, the idea is close to VJ's one, only timestamp cache is
145 held not per host, but per port pair and TW bucket is used as state
146 holder.
147
148 If TW bucket has been already destroyed we fall back to VJ's scheme
149 and use initial timestamp retrieved from peer table.
150 */
151 if (tcptw->tw_ts_recent_stamp &&
152 (!twp || (reuse && time_after32(ktime_get_seconds(),
153 tcptw->tw_ts_recent_stamp)))) {
154 /* In case of repair and re-using TIME-WAIT sockets we still
155 * want to be sure that it is safe as above but honor the
156 * sequence numbers and time stamps set as part of the repair
157 * process.
158 *
159 * Without this check re-using a TIME-WAIT socket with TCP
160 * repair would accumulate a -1 on the repair assigned
161 * sequence number. The first time it is reused the sequence
162 * is -1, the second time -2, etc. This fixes that issue
163 * without appearing to create any others.
164 */
165 if (likely(!tp->repair)) {
166 u32 seq = tcptw->tw_snd_nxt + 65535 + 2;
167
168 if (!seq)
169 seq = 1;
170 WRITE_ONCE(tp->write_seq, seq);
171 tp->rx_opt.ts_recent = tcptw->tw_ts_recent;
172 tp->rx_opt.ts_recent_stamp = tcptw->tw_ts_recent_stamp;
173 }
174 sock_hold(sktw);
175 return 1;
176 }
177
178 return 0;
179}
180EXPORT_SYMBOL_GPL(tcp_twsk_unique);
181
182static int tcp_v4_pre_connect(struct sock *sk, struct sockaddr *uaddr,
183 int addr_len)
184{
185 /* This check is replicated from tcp_v4_connect() and intended to
186 * prevent BPF program called below from accessing bytes that are out
187 * of the bound specified by user in addr_len.
188 */
189 if (addr_len < sizeof(struct sockaddr_in))
190 return -EINVAL;
191
192 sock_owned_by_me(sk);
193
194 return BPF_CGROUP_RUN_PROG_INET4_CONNECT(sk, uaddr);
195}
196
197/* This will initiate an outgoing connection. */
198int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
199{
200 struct sockaddr_in *usin = (struct sockaddr_in *)uaddr;
201 struct inet_sock *inet = inet_sk(sk);
202 struct tcp_sock *tp = tcp_sk(sk);
203 __be16 orig_sport, orig_dport;
204 __be32 daddr, nexthop;
205 struct flowi4 *fl4;
206 struct rtable *rt;
207 int err;
208 struct ip_options_rcu *inet_opt;
209 struct inet_timewait_death_row *tcp_death_row = &sock_net(sk)->ipv4.tcp_death_row;
210
211 if (addr_len < sizeof(struct sockaddr_in))
212 return -EINVAL;
213
214 if (usin->sin_family != AF_INET)
215 return -EAFNOSUPPORT;
216
217 nexthop = daddr = usin->sin_addr.s_addr;
218 inet_opt = rcu_dereference_protected(inet->inet_opt,
219 lockdep_sock_is_held(sk));
220 if (inet_opt && inet_opt->opt.srr) {
221 if (!daddr)
222 return -EINVAL;
223 nexthop = inet_opt->opt.faddr;
224 }
225
226 orig_sport = inet->inet_sport;
227 orig_dport = usin->sin_port;
228 fl4 = &inet->cork.fl.u.ip4;
229 rt = ip_route_connect(fl4, nexthop, inet->inet_saddr,
230 RT_CONN_FLAGS(sk), sk->sk_bound_dev_if,
231 IPPROTO_TCP,
232 orig_sport, orig_dport, sk);
233 if (IS_ERR(rt)) {
234 err = PTR_ERR(rt);
235 if (err == -ENETUNREACH)
236 IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTNOROUTES);
237 return err;
238 }
239
240 if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) {
241 ip_rt_put(rt);
242 return -ENETUNREACH;
243 }
244
245 if (!inet_opt || !inet_opt->opt.srr)
246 daddr = fl4->daddr;
247
248 if (!inet->inet_saddr)
249 inet->inet_saddr = fl4->saddr;
250 sk_rcv_saddr_set(sk, inet->inet_saddr);
251
252 if (tp->rx_opt.ts_recent_stamp && inet->inet_daddr != daddr) {
253 /* Reset inherited state */
254 tp->rx_opt.ts_recent = 0;
255 tp->rx_opt.ts_recent_stamp = 0;
256 if (likely(!tp->repair))
257 WRITE_ONCE(tp->write_seq, 0);
258 }
259
260 inet->inet_dport = usin->sin_port;
261 sk_daddr_set(sk, daddr);
262
263 inet_csk(sk)->icsk_ext_hdr_len = 0;
264 if (inet_opt)
265 inet_csk(sk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
266
267 tp->rx_opt.mss_clamp = TCP_MSS_DEFAULT;
268
269 /* Socket identity is still unknown (sport may be zero).
270 * However we set state to SYN-SENT and not releasing socket
271 * lock select source port, enter ourselves into the hash tables and
272 * complete initialization after this.
273 */
274 tcp_set_state(sk, TCP_SYN_SENT);
275 err = inet_hash_connect(tcp_death_row, sk);
276 if (err)
277 goto failure;
278
279 sk_set_txhash(sk);
280
281 rt = ip_route_newports(fl4, rt, orig_sport, orig_dport,
282 inet->inet_sport, inet->inet_dport, sk);
283 if (IS_ERR(rt)) {
284 err = PTR_ERR(rt);
285 rt = NULL;
286 goto failure;
287 }
288 /* OK, now commit destination to socket. */
289 sk->sk_gso_type = SKB_GSO_TCPV4;
290 sk_setup_caps(sk, &rt->dst);
291 rt = NULL;
292
293 if (likely(!tp->repair)) {
294 if (!tp->write_seq)
295 WRITE_ONCE(tp->write_seq,
296 secure_tcp_seq(inet->inet_saddr,
297 inet->inet_daddr,
298 inet->inet_sport,
299 usin->sin_port));
300 tp->tsoffset = secure_tcp_ts_off(sock_net(sk),
301 inet->inet_saddr,
302 inet->inet_daddr);
303 }
304
305 inet->inet_id = prandom_u32();
306
307 if (tcp_fastopen_defer_connect(sk, &err))
308 return err;
309 if (err)
310 goto failure;
311
312 err = tcp_connect(sk);
313
314 if (err)
315 goto failure;
316
317 return 0;
318
319failure:
320 /*
321 * This unhashes the socket and releases the local port,
322 * if necessary.
323 */
324 tcp_set_state(sk, TCP_CLOSE);
325 ip_rt_put(rt);
326 sk->sk_route_caps = 0;
327 inet->inet_dport = 0;
328 return err;
329}
330EXPORT_SYMBOL(tcp_v4_connect);
331
332/*
333 * This routine reacts to ICMP_FRAG_NEEDED mtu indications as defined in RFC1191.
334 * It can be called through tcp_release_cb() if socket was owned by user
335 * at the time tcp_v4_err() was called to handle ICMP message.
336 */
337void tcp_v4_mtu_reduced(struct sock *sk)
338{
339 struct inet_sock *inet = inet_sk(sk);
340 struct dst_entry *dst;
341 u32 mtu;
342
343 if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE))
344 return;
345 mtu = READ_ONCE(tcp_sk(sk)->mtu_info);
346 dst = inet_csk_update_pmtu(sk, mtu);
347 if (!dst)
348 return;
349
350 /* Something is about to be wrong... Remember soft error
351 * for the case, if this connection will not able to recover.
352 */
353 if (mtu < dst_mtu(dst) && ip_dont_fragment(sk, dst))
354 sk->sk_err_soft = EMSGSIZE;
355
356 mtu = dst_mtu(dst);
357
358 if (inet->pmtudisc != IP_PMTUDISC_DONT &&
359 ip_sk_accept_pmtu(sk) &&
360 inet_csk(sk)->icsk_pmtu_cookie > mtu) {
361 tcp_sync_mss(sk, mtu);
362
363 /* Resend the TCP packet because it's
364 * clear that the old packet has been
365 * dropped. This is the new "fast" path mtu
366 * discovery.
367 */
368 tcp_simple_retransmit(sk);
369 } /* else let the usual retransmit timer handle it */
370}
371EXPORT_SYMBOL(tcp_v4_mtu_reduced);
372
373static void do_redirect(struct sk_buff *skb, struct sock *sk)
374{
375 struct dst_entry *dst = __sk_dst_check(sk, 0);
376
377 if (dst)
378 dst->ops->redirect(dst, sk, skb);
379}
380
381
382/* handle ICMP messages on TCP_NEW_SYN_RECV request sockets */
383void tcp_req_err(struct sock *sk, u32 seq, bool abort)
384{
385 struct request_sock *req = inet_reqsk(sk);
386 struct net *net = sock_net(sk);
387
388 /* ICMPs are not backlogged, hence we cannot get
389 * an established socket here.
390 */
391 if (seq != tcp_rsk(req)->snt_isn) {
392 __NET_INC_STATS(net, LINUX_MIB_OUTOFWINDOWICMPS);
393 } else if (abort) {
394 /*
395 * Still in SYN_RECV, just remove it silently.
396 * There is no good way to pass the error to the newly
397 * created socket, and POSIX does not want network
398 * errors returned from accept().
399 */
400 inet_csk_reqsk_queue_drop(req->rsk_listener, req);
401 tcp_listendrop(req->rsk_listener);
402 }
403 reqsk_put(req);
404}
405EXPORT_SYMBOL(tcp_req_err);
406
407/* TCP-LD (RFC 6069) logic */
408void tcp_ld_RTO_revert(struct sock *sk, u32 seq)
409{
410 struct inet_connection_sock *icsk = inet_csk(sk);
411 struct tcp_sock *tp = tcp_sk(sk);
412 struct sk_buff *skb;
413 s32 remaining;
414 u32 delta_us;
415
416 if (sock_owned_by_user(sk))
417 return;
418
419 if (seq != tp->snd_una || !icsk->icsk_retransmits ||
420 !icsk->icsk_backoff)
421 return;
422
423 skb = tcp_rtx_queue_head(sk);
424 if (WARN_ON_ONCE(!skb))
425 return;
426
427 icsk->icsk_backoff--;
428 icsk->icsk_rto = tp->srtt_us ? __tcp_set_rto(tp) : TCP_TIMEOUT_INIT;
429 icsk->icsk_rto = inet_csk_rto_backoff(icsk, TCP_RTO_MAX);
430
431 tcp_mstamp_refresh(tp);
432 delta_us = (u32)(tp->tcp_mstamp - tcp_skb_timestamp_us(skb));
433 remaining = icsk->icsk_rto - usecs_to_jiffies(delta_us);
434
435 if (remaining > 0) {
436 inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
437 remaining, TCP_RTO_MAX);
438 } else {
439 /* RTO revert clocked out retransmission.
440 * Will retransmit now.
441 */
442 tcp_retransmit_timer(sk);
443 }
444}
445EXPORT_SYMBOL(tcp_ld_RTO_revert);
446
447/*
448 * This routine is called by the ICMP module when it gets some
449 * sort of error condition. If err < 0 then the socket should
450 * be closed and the error returned to the user. If err > 0
451 * it's just the icmp type << 8 | icmp code. After adjustment
452 * header points to the first 8 bytes of the tcp header. We need
453 * to find the appropriate port.
454 *
455 * The locking strategy used here is very "optimistic". When
456 * someone else accesses the socket the ICMP is just dropped
457 * and for some paths there is no check at all.
458 * A more general error queue to queue errors for later handling
459 * is probably better.
460 *
461 */
462
463int tcp_v4_err(struct sk_buff *skb, u32 info)
464{
465 const struct iphdr *iph = (const struct iphdr *)skb->data;
466 struct tcphdr *th = (struct tcphdr *)(skb->data + (iph->ihl << 2));
467 struct tcp_sock *tp;
468 struct inet_sock *inet;
469 const int type = icmp_hdr(skb)->type;
470 const int code = icmp_hdr(skb)->code;
471 struct sock *sk;
472 struct request_sock *fastopen;
473 u32 seq, snd_una;
474 int err;
475 struct net *net = dev_net(skb->dev);
476
477 sk = __inet_lookup_established(net, &tcp_hashinfo, iph->daddr,
478 th->dest, iph->saddr, ntohs(th->source),
479 inet_iif(skb), 0);
480 if (!sk) {
481 __ICMP_INC_STATS(net, ICMP_MIB_INERRORS);
482 return -ENOENT;
483 }
484 if (sk->sk_state == TCP_TIME_WAIT) {
485 inet_twsk_put(inet_twsk(sk));
486 return 0;
487 }
488 seq = ntohl(th->seq);
489 if (sk->sk_state == TCP_NEW_SYN_RECV) {
490 tcp_req_err(sk, seq, type == ICMP_PARAMETERPROB ||
491 type == ICMP_TIME_EXCEEDED ||
492 (type == ICMP_DEST_UNREACH &&
493 (code == ICMP_NET_UNREACH ||
494 code == ICMP_HOST_UNREACH)));
495 return 0;
496 }
497
498 bh_lock_sock(sk);
499 /* If too many ICMPs get dropped on busy
500 * servers this needs to be solved differently.
501 * We do take care of PMTU discovery (RFC1191) special case :
502 * we can receive locally generated ICMP messages while socket is held.
503 */
504 if (sock_owned_by_user(sk)) {
505 if (!(type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED))
506 __NET_INC_STATS(net, LINUX_MIB_LOCKDROPPEDICMPS);
507 }
508 if (sk->sk_state == TCP_CLOSE)
509 goto out;
510
511 if (unlikely(iph->ttl < inet_sk(sk)->min_ttl)) {
512 __NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP);
513 goto out;
514 }
515
516 tp = tcp_sk(sk);
517 /* XXX (TFO) - tp->snd_una should be ISN (tcp_create_openreq_child() */
518 fastopen = rcu_dereference(tp->fastopen_rsk);
519 snd_una = fastopen ? tcp_rsk(fastopen)->snt_isn : tp->snd_una;
520 if (sk->sk_state != TCP_LISTEN &&
521 !between(seq, snd_una, tp->snd_nxt)) {
522 __NET_INC_STATS(net, LINUX_MIB_OUTOFWINDOWICMPS);
523 goto out;
524 }
525
526 switch (type) {
527 case ICMP_REDIRECT:
528 if (!sock_owned_by_user(sk))
529 do_redirect(skb, sk);
530 goto out;
531 case ICMP_SOURCE_QUENCH:
532 /* Just silently ignore these. */
533 goto out;
534 case ICMP_PARAMETERPROB:
535 err = EPROTO;
536 break;
537 case ICMP_DEST_UNREACH:
538 if (code > NR_ICMP_UNREACH)
539 goto out;
540
541 if (code == ICMP_FRAG_NEEDED) { /* PMTU discovery (RFC1191) */
542 /* We are not interested in TCP_LISTEN and open_requests
543 * (SYN-ACKs send out by Linux are always <576bytes so
544 * they should go through unfragmented).
545 */
546 if (sk->sk_state == TCP_LISTEN)
547 goto out;
548
549 WRITE_ONCE(tp->mtu_info, info);
550 if (!sock_owned_by_user(sk)) {
551 tcp_v4_mtu_reduced(sk);
552 } else {
553 if (!test_and_set_bit(TCP_MTU_REDUCED_DEFERRED, &sk->sk_tsq_flags))
554 sock_hold(sk);
555 }
556 goto out;
557 }
558
559 err = icmp_err_convert[code].errno;
560 /* check if this ICMP message allows revert of backoff.
561 * (see RFC 6069)
562 */
563 if (!fastopen &&
564 (code == ICMP_NET_UNREACH || code == ICMP_HOST_UNREACH))
565 tcp_ld_RTO_revert(sk, seq);
566 break;
567 case ICMP_TIME_EXCEEDED:
568 err = EHOSTUNREACH;
569 break;
570 default:
571 goto out;
572 }
573
574 switch (sk->sk_state) {
575 case TCP_SYN_SENT:
576 case TCP_SYN_RECV:
577 /* Only in fast or simultaneous open. If a fast open socket is
578 * already accepted it is treated as a connected one below.
579 */
580 if (fastopen && !fastopen->sk)
581 break;
582
583 ip_icmp_error(sk, skb, err, th->dest, info, (u8 *)th);
584
585 if (!sock_owned_by_user(sk)) {
586 sk->sk_err = err;
587
588 sk_error_report(sk);
589
590 tcp_done(sk);
591 } else {
592 sk->sk_err_soft = err;
593 }
594 goto out;
595 }
596
597 /* If we've already connected we will keep trying
598 * until we time out, or the user gives up.
599 *
600 * rfc1122 4.2.3.9 allows to consider as hard errors
601 * only PROTO_UNREACH and PORT_UNREACH (well, FRAG_FAILED too,
602 * but it is obsoleted by pmtu discovery).
603 *
604 * Note, that in modern internet, where routing is unreliable
605 * and in each dark corner broken firewalls sit, sending random
606 * errors ordered by their masters even this two messages finally lose
607 * their original sense (even Linux sends invalid PORT_UNREACHs)
608 *
609 * Now we are in compliance with RFCs.
610 * --ANK (980905)
611 */
612
613 inet = inet_sk(sk);
614 if (!sock_owned_by_user(sk) && inet->recverr) {
615 sk->sk_err = err;
616 sk_error_report(sk);
617 } else { /* Only an error on timeout */
618 sk->sk_err_soft = err;
619 }
620
621out:
622 bh_unlock_sock(sk);
623 sock_put(sk);
624 return 0;
625}
626
627void __tcp_v4_send_check(struct sk_buff *skb, __be32 saddr, __be32 daddr)
628{
629 struct tcphdr *th = tcp_hdr(skb);
630
631 th->check = ~tcp_v4_check(skb->len, saddr, daddr, 0);
632 skb->csum_start = skb_transport_header(skb) - skb->head;
633 skb->csum_offset = offsetof(struct tcphdr, check);
634}
635
636/* This routine computes an IPv4 TCP checksum. */
637void tcp_v4_send_check(struct sock *sk, struct sk_buff *skb)
638{
639 const struct inet_sock *inet = inet_sk(sk);
640
641 __tcp_v4_send_check(skb, inet->inet_saddr, inet->inet_daddr);
642}
643EXPORT_SYMBOL(tcp_v4_send_check);
644
645/*
646 * This routine will send an RST to the other tcp.
647 *
648 * Someone asks: why I NEVER use socket parameters (TOS, TTL etc.)
649 * for reset.
650 * Answer: if a packet caused RST, it is not for a socket
651 * existing in our system, if it is matched to a socket,
652 * it is just duplicate segment or bug in other side's TCP.
653 * So that we build reply only basing on parameters
654 * arrived with segment.
655 * Exception: precedence violation. We do not implement it in any case.
656 */
657
658#ifdef CONFIG_TCP_MD5SIG
659#define OPTION_BYTES TCPOLEN_MD5SIG_ALIGNED
660#else
661#define OPTION_BYTES sizeof(__be32)
662#endif
663
664static void tcp_v4_send_reset(const struct sock *sk, struct sk_buff *skb)
665{
666 const struct tcphdr *th = tcp_hdr(skb);
667 struct {
668 struct tcphdr th;
669 __be32 opt[OPTION_BYTES / sizeof(__be32)];
670 } rep;
671 struct ip_reply_arg arg;
672#ifdef CONFIG_TCP_MD5SIG
673 struct tcp_md5sig_key *key = NULL;
674 const __u8 *hash_location = NULL;
675 unsigned char newhash[16];
676 int genhash;
677 struct sock *sk1 = NULL;
678#endif
679 u64 transmit_time = 0;
680 struct sock *ctl_sk;
681 struct net *net;
682
683 /* Never send a reset in response to a reset. */
684 if (th->rst)
685 return;
686
687 /* If sk not NULL, it means we did a successful lookup and incoming
688 * route had to be correct. prequeue might have dropped our dst.
689 */
690 if (!sk && skb_rtable(skb)->rt_type != RTN_LOCAL)
691 return;
692
693 /* Swap the send and the receive. */
694 memset(&rep, 0, sizeof(rep));
695 rep.th.dest = th->source;
696 rep.th.source = th->dest;
697 rep.th.doff = sizeof(struct tcphdr) / 4;
698 rep.th.rst = 1;
699
700 if (th->ack) {
701 rep.th.seq = th->ack_seq;
702 } else {
703 rep.th.ack = 1;
704 rep.th.ack_seq = htonl(ntohl(th->seq) + th->syn + th->fin +
705 skb->len - (th->doff << 2));
706 }
707
708 memset(&arg, 0, sizeof(arg));
709 arg.iov[0].iov_base = (unsigned char *)&rep;
710 arg.iov[0].iov_len = sizeof(rep.th);
711
712 net = sk ? sock_net(sk) : dev_net(skb_dst(skb)->dev);
713#ifdef CONFIG_TCP_MD5SIG
714 rcu_read_lock();
715 hash_location = tcp_parse_md5sig_option(th);
716 if (sk && sk_fullsock(sk)) {
717 const union tcp_md5_addr *addr;
718 int l3index;
719
720 /* sdif set, means packet ingressed via a device
721 * in an L3 domain and inet_iif is set to it.
722 */
723 l3index = tcp_v4_sdif(skb) ? inet_iif(skb) : 0;
724 addr = (union tcp_md5_addr *)&ip_hdr(skb)->saddr;
725 key = tcp_md5_do_lookup(sk, l3index, addr, AF_INET);
726 } else if (hash_location) {
727 const union tcp_md5_addr *addr;
728 int sdif = tcp_v4_sdif(skb);
729 int dif = inet_iif(skb);
730 int l3index;
731
732 /*
733 * active side is lost. Try to find listening socket through
734 * source port, and then find md5 key through listening socket.
735 * we are not loose security here:
736 * Incoming packet is checked with md5 hash with finding key,
737 * no RST generated if md5 hash doesn't match.
738 */
739 sk1 = __inet_lookup_listener(net, &tcp_hashinfo, NULL, 0,
740 ip_hdr(skb)->saddr,
741 th->source, ip_hdr(skb)->daddr,
742 ntohs(th->source), dif, sdif);
743 /* don't send rst if it can't find key */
744 if (!sk1)
745 goto out;
746
747 /* sdif set, means packet ingressed via a device
748 * in an L3 domain and dif is set to it.
749 */
750 l3index = sdif ? dif : 0;
751 addr = (union tcp_md5_addr *)&ip_hdr(skb)->saddr;
752 key = tcp_md5_do_lookup(sk1, l3index, addr, AF_INET);
753 if (!key)
754 goto out;
755
756
757 genhash = tcp_v4_md5_hash_skb(newhash, key, NULL, skb);
758 if (genhash || memcmp(hash_location, newhash, 16) != 0)
759 goto out;
760
761 }
762
763 if (key) {
764 rep.opt[0] = htonl((TCPOPT_NOP << 24) |
765 (TCPOPT_NOP << 16) |
766 (TCPOPT_MD5SIG << 8) |
767 TCPOLEN_MD5SIG);
768 /* Update length and the length the header thinks exists */
769 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED;
770 rep.th.doff = arg.iov[0].iov_len / 4;
771
772 tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[1],
773 key, ip_hdr(skb)->saddr,
774 ip_hdr(skb)->daddr, &rep.th);
775 }
776#endif
777 /* Can't co-exist with TCPMD5, hence check rep.opt[0] */
778 if (rep.opt[0] == 0) {
779 __be32 mrst = mptcp_reset_option(skb);
780
781 if (mrst) {
782 rep.opt[0] = mrst;
783 arg.iov[0].iov_len += sizeof(mrst);
784 rep.th.doff = arg.iov[0].iov_len / 4;
785 }
786 }
787
788 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
789 ip_hdr(skb)->saddr, /* XXX */
790 arg.iov[0].iov_len, IPPROTO_TCP, 0);
791 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
792 arg.flags = (sk && inet_sk_transparent(sk)) ? IP_REPLY_ARG_NOSRCCHECK : 0;
793
794 /* When socket is gone, all binding information is lost.
795 * routing might fail in this case. No choice here, if we choose to force
796 * input interface, we will misroute in case of asymmetric route.
797 */
798 if (sk) {
799 arg.bound_dev_if = sk->sk_bound_dev_if;
800 if (sk_fullsock(sk))
801 trace_tcp_send_reset(sk, skb);
802 }
803
804 BUILD_BUG_ON(offsetof(struct sock, sk_bound_dev_if) !=
805 offsetof(struct inet_timewait_sock, tw_bound_dev_if));
806
807 arg.tos = ip_hdr(skb)->tos;
808 arg.uid = sock_net_uid(net, sk && sk_fullsock(sk) ? sk : NULL);
809 local_bh_disable();
810 ctl_sk = this_cpu_read(*net->ipv4.tcp_sk);
811 if (sk) {
812 ctl_sk->sk_mark = (sk->sk_state == TCP_TIME_WAIT) ?
813 inet_twsk(sk)->tw_mark : sk->sk_mark;
814 ctl_sk->sk_priority = (sk->sk_state == TCP_TIME_WAIT) ?
815 inet_twsk(sk)->tw_priority : sk->sk_priority;
816 transmit_time = tcp_transmit_time(sk);
817 }
818 ip_send_unicast_reply(ctl_sk,
819 skb, &TCP_SKB_CB(skb)->header.h4.opt,
820 ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
821 &arg, arg.iov[0].iov_len,
822 transmit_time);
823
824 ctl_sk->sk_mark = 0;
825 __TCP_INC_STATS(net, TCP_MIB_OUTSEGS);
826 __TCP_INC_STATS(net, TCP_MIB_OUTRSTS);
827 local_bh_enable();
828
829#ifdef CONFIG_TCP_MD5SIG
830out:
831 rcu_read_unlock();
832#endif
833}
834
835/* The code following below sending ACKs in SYN-RECV and TIME-WAIT states
836 outside socket context is ugly, certainly. What can I do?
837 */
838
839static void tcp_v4_send_ack(const struct sock *sk,
840 struct sk_buff *skb, u32 seq, u32 ack,
841 u32 win, u32 tsval, u32 tsecr, int oif,
842 struct tcp_md5sig_key *key,
843 int reply_flags, u8 tos)
844{
845 const struct tcphdr *th = tcp_hdr(skb);
846 struct {
847 struct tcphdr th;
848 __be32 opt[(TCPOLEN_TSTAMP_ALIGNED >> 2)
849#ifdef CONFIG_TCP_MD5SIG
850 + (TCPOLEN_MD5SIG_ALIGNED >> 2)
851#endif
852 ];
853 } rep;
854 struct net *net = sock_net(sk);
855 struct ip_reply_arg arg;
856 struct sock *ctl_sk;
857 u64 transmit_time;
858
859 memset(&rep.th, 0, sizeof(struct tcphdr));
860 memset(&arg, 0, sizeof(arg));
861
862 arg.iov[0].iov_base = (unsigned char *)&rep;
863 arg.iov[0].iov_len = sizeof(rep.th);
864 if (tsecr) {
865 rep.opt[0] = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
866 (TCPOPT_TIMESTAMP << 8) |
867 TCPOLEN_TIMESTAMP);
868 rep.opt[1] = htonl(tsval);
869 rep.opt[2] = htonl(tsecr);
870 arg.iov[0].iov_len += TCPOLEN_TSTAMP_ALIGNED;
871 }
872
873 /* Swap the send and the receive. */
874 rep.th.dest = th->source;
875 rep.th.source = th->dest;
876 rep.th.doff = arg.iov[0].iov_len / 4;
877 rep.th.seq = htonl(seq);
878 rep.th.ack_seq = htonl(ack);
879 rep.th.ack = 1;
880 rep.th.window = htons(win);
881
882#ifdef CONFIG_TCP_MD5SIG
883 if (key) {
884 int offset = (tsecr) ? 3 : 0;
885
886 rep.opt[offset++] = htonl((TCPOPT_NOP << 24) |
887 (TCPOPT_NOP << 16) |
888 (TCPOPT_MD5SIG << 8) |
889 TCPOLEN_MD5SIG);
890 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED;
891 rep.th.doff = arg.iov[0].iov_len/4;
892
893 tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[offset],
894 key, ip_hdr(skb)->saddr,
895 ip_hdr(skb)->daddr, &rep.th);
896 }
897#endif
898 arg.flags = reply_flags;
899 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
900 ip_hdr(skb)->saddr, /* XXX */
901 arg.iov[0].iov_len, IPPROTO_TCP, 0);
902 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
903 if (oif)
904 arg.bound_dev_if = oif;
905 arg.tos = tos;
906 arg.uid = sock_net_uid(net, sk_fullsock(sk) ? sk : NULL);
907 local_bh_disable();
908 ctl_sk = this_cpu_read(*net->ipv4.tcp_sk);
909 ctl_sk->sk_mark = (sk->sk_state == TCP_TIME_WAIT) ?
910 inet_twsk(sk)->tw_mark : sk->sk_mark;
911 ctl_sk->sk_priority = (sk->sk_state == TCP_TIME_WAIT) ?
912 inet_twsk(sk)->tw_priority : sk->sk_priority;
913 transmit_time = tcp_transmit_time(sk);
914 ip_send_unicast_reply(ctl_sk,
915 skb, &TCP_SKB_CB(skb)->header.h4.opt,
916 ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
917 &arg, arg.iov[0].iov_len,
918 transmit_time);
919
920 ctl_sk->sk_mark = 0;
921 __TCP_INC_STATS(net, TCP_MIB_OUTSEGS);
922 local_bh_enable();
923}
924
925static void tcp_v4_timewait_ack(struct sock *sk, struct sk_buff *skb)
926{
927 struct inet_timewait_sock *tw = inet_twsk(sk);
928 struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
929
930 tcp_v4_send_ack(sk, skb,
931 tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
932 tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
933 tcp_time_stamp_raw() + tcptw->tw_ts_offset,
934 tcptw->tw_ts_recent,
935 tw->tw_bound_dev_if,
936 tcp_twsk_md5_key(tcptw),
937 tw->tw_transparent ? IP_REPLY_ARG_NOSRCCHECK : 0,
938 tw->tw_tos
939 );
940
941 inet_twsk_put(tw);
942}
943
944static void tcp_v4_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb,
945 struct request_sock *req)
946{
947 const union tcp_md5_addr *addr;
948 int l3index;
949
950 /* sk->sk_state == TCP_LISTEN -> for regular TCP_SYN_RECV
951 * sk->sk_state == TCP_SYN_RECV -> for Fast Open.
952 */
953 u32 seq = (sk->sk_state == TCP_LISTEN) ? tcp_rsk(req)->snt_isn + 1 :
954 tcp_sk(sk)->snd_nxt;
955
956 /* RFC 7323 2.3
957 * The window field (SEG.WND) of every outgoing segment, with the
958 * exception of <SYN> segments, MUST be right-shifted by
959 * Rcv.Wind.Shift bits:
960 */
961 addr = (union tcp_md5_addr *)&ip_hdr(skb)->saddr;
962 l3index = tcp_v4_sdif(skb) ? inet_iif(skb) : 0;
963 tcp_v4_send_ack(sk, skb, seq,
964 tcp_rsk(req)->rcv_nxt,
965 req->rsk_rcv_wnd >> inet_rsk(req)->rcv_wscale,
966 tcp_time_stamp_raw() + tcp_rsk(req)->ts_off,
967 req->ts_recent,
968 0,
969 tcp_md5_do_lookup(sk, l3index, addr, AF_INET),
970 inet_rsk(req)->no_srccheck ? IP_REPLY_ARG_NOSRCCHECK : 0,
971 ip_hdr(skb)->tos);
972}
973
974/*
975 * Send a SYN-ACK after having received a SYN.
976 * This still operates on a request_sock only, not on a big
977 * socket.
978 */
979static int tcp_v4_send_synack(const struct sock *sk, struct dst_entry *dst,
980 struct flowi *fl,
981 struct request_sock *req,
982 struct tcp_fastopen_cookie *foc,
983 enum tcp_synack_type synack_type,
984 struct sk_buff *syn_skb)
985{
986 const struct inet_request_sock *ireq = inet_rsk(req);
987 struct flowi4 fl4;
988 int err = -1;
989 struct sk_buff *skb;
990 u8 tos;
991
992 /* First, grab a route. */
993 if (!dst && (dst = inet_csk_route_req(sk, &fl4, req)) == NULL)
994 return -1;
995
996 skb = tcp_make_synack(sk, dst, req, foc, synack_type, syn_skb);
997
998 if (skb) {
999 __tcp_v4_send_check(skb, ireq->ir_loc_addr, ireq->ir_rmt_addr);
1000
1001 tos = sock_net(sk)->ipv4.sysctl_tcp_reflect_tos ?
1002 (tcp_rsk(req)->syn_tos & ~INET_ECN_MASK) |
1003 (inet_sk(sk)->tos & INET_ECN_MASK) :
1004 inet_sk(sk)->tos;
1005
1006 if (!INET_ECN_is_capable(tos) &&
1007 tcp_bpf_ca_needs_ecn((struct sock *)req))
1008 tos |= INET_ECN_ECT_0;
1009
1010 rcu_read_lock();
1011 err = ip_build_and_send_pkt(skb, sk, ireq->ir_loc_addr,
1012 ireq->ir_rmt_addr,
1013 rcu_dereference(ireq->ireq_opt),
1014 tos);
1015 rcu_read_unlock();
1016 err = net_xmit_eval(err);
1017 }
1018
1019 return err;
1020}
1021
1022/*
1023 * IPv4 request_sock destructor.
1024 */
1025static void tcp_v4_reqsk_destructor(struct request_sock *req)
1026{
1027 kfree(rcu_dereference_protected(inet_rsk(req)->ireq_opt, 1));
1028}
1029
1030#ifdef CONFIG_TCP_MD5SIG
1031/*
1032 * RFC2385 MD5 checksumming requires a mapping of
1033 * IP address->MD5 Key.
1034 * We need to maintain these in the sk structure.
1035 */
1036
1037DEFINE_STATIC_KEY_FALSE(tcp_md5_needed);
1038EXPORT_SYMBOL(tcp_md5_needed);
1039
1040static bool better_md5_match(struct tcp_md5sig_key *old, struct tcp_md5sig_key *new)
1041{
1042 if (!old)
1043 return true;
1044
1045 /* l3index always overrides non-l3index */
1046 if (old->l3index && new->l3index == 0)
1047 return false;
1048 if (old->l3index == 0 && new->l3index)
1049 return true;
1050
1051 return old->prefixlen < new->prefixlen;
1052}
1053
1054/* Find the Key structure for an address. */
1055struct tcp_md5sig_key *__tcp_md5_do_lookup(const struct sock *sk, int l3index,
1056 const union tcp_md5_addr *addr,
1057 int family)
1058{
1059 const struct tcp_sock *tp = tcp_sk(sk);
1060 struct tcp_md5sig_key *key;
1061 const struct tcp_md5sig_info *md5sig;
1062 __be32 mask;
1063 struct tcp_md5sig_key *best_match = NULL;
1064 bool match;
1065
1066 /* caller either holds rcu_read_lock() or socket lock */
1067 md5sig = rcu_dereference_check(tp->md5sig_info,
1068 lockdep_sock_is_held(sk));
1069 if (!md5sig)
1070 return NULL;
1071
1072 hlist_for_each_entry_rcu(key, &md5sig->head, node,
1073 lockdep_sock_is_held(sk)) {
1074 if (key->family != family)
1075 continue;
1076 if (key->l3index && key->l3index != l3index)
1077 continue;
1078 if (family == AF_INET) {
1079 mask = inet_make_mask(key->prefixlen);
1080 match = (key->addr.a4.s_addr & mask) ==
1081 (addr->a4.s_addr & mask);
1082#if IS_ENABLED(CONFIG_IPV6)
1083 } else if (family == AF_INET6) {
1084 match = ipv6_prefix_equal(&key->addr.a6, &addr->a6,
1085 key->prefixlen);
1086#endif
1087 } else {
1088 match = false;
1089 }
1090
1091 if (match && better_md5_match(best_match, key))
1092 best_match = key;
1093 }
1094 return best_match;
1095}
1096EXPORT_SYMBOL(__tcp_md5_do_lookup);
1097
1098static struct tcp_md5sig_key *tcp_md5_do_lookup_exact(const struct sock *sk,
1099 const union tcp_md5_addr *addr,
1100 int family, u8 prefixlen,
1101 int l3index)
1102{
1103 const struct tcp_sock *tp = tcp_sk(sk);
1104 struct tcp_md5sig_key *key;
1105 unsigned int size = sizeof(struct in_addr);
1106 const struct tcp_md5sig_info *md5sig;
1107
1108 /* caller either holds rcu_read_lock() or socket lock */
1109 md5sig = rcu_dereference_check(tp->md5sig_info,
1110 lockdep_sock_is_held(sk));
1111 if (!md5sig)
1112 return NULL;
1113#if IS_ENABLED(CONFIG_IPV6)
1114 if (family == AF_INET6)
1115 size = sizeof(struct in6_addr);
1116#endif
1117 hlist_for_each_entry_rcu(key, &md5sig->head, node,
1118 lockdep_sock_is_held(sk)) {
1119 if (key->family != family)
1120 continue;
1121 if (key->l3index != l3index)
1122 continue;
1123 if (!memcmp(&key->addr, addr, size) &&
1124 key->prefixlen == prefixlen)
1125 return key;
1126 }
1127 return NULL;
1128}
1129
1130struct tcp_md5sig_key *tcp_v4_md5_lookup(const struct sock *sk,
1131 const struct sock *addr_sk)
1132{
1133 const union tcp_md5_addr *addr;
1134 int l3index;
1135
1136 l3index = l3mdev_master_ifindex_by_index(sock_net(sk),
1137 addr_sk->sk_bound_dev_if);
1138 addr = (const union tcp_md5_addr *)&addr_sk->sk_daddr;
1139 return tcp_md5_do_lookup(sk, l3index, addr, AF_INET);
1140}
1141EXPORT_SYMBOL(tcp_v4_md5_lookup);
1142
1143/* This can be called on a newly created socket, from other files */
1144int tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr,
1145 int family, u8 prefixlen, int l3index,
1146 const u8 *newkey, u8 newkeylen, gfp_t gfp)
1147{
1148 /* Add Key to the list */
1149 struct tcp_md5sig_key *key;
1150 struct tcp_sock *tp = tcp_sk(sk);
1151 struct tcp_md5sig_info *md5sig;
1152
1153 key = tcp_md5_do_lookup_exact(sk, addr, family, prefixlen, l3index);
1154 if (key) {
1155 /* Pre-existing entry - just update that one.
1156 * Note that the key might be used concurrently.
1157 * data_race() is telling kcsan that we do not care of
1158 * key mismatches, since changing MD5 key on live flows
1159 * can lead to packet drops.
1160 */
1161 data_race(memcpy(key->key, newkey, newkeylen));
1162
1163 /* Pairs with READ_ONCE() in tcp_md5_hash_key().
1164 * Also note that a reader could catch new key->keylen value
1165 * but old key->key[], this is the reason we use __GFP_ZERO
1166 * at sock_kmalloc() time below these lines.
1167 */
1168 WRITE_ONCE(key->keylen, newkeylen);
1169
1170 return 0;
1171 }
1172
1173 md5sig = rcu_dereference_protected(tp->md5sig_info,
1174 lockdep_sock_is_held(sk));
1175 if (!md5sig) {
1176 md5sig = kmalloc(sizeof(*md5sig), gfp);
1177 if (!md5sig)
1178 return -ENOMEM;
1179
1180 sk_nocaps_add(sk, NETIF_F_GSO_MASK);
1181 INIT_HLIST_HEAD(&md5sig->head);
1182 rcu_assign_pointer(tp->md5sig_info, md5sig);
1183 }
1184
1185 key = sock_kmalloc(sk, sizeof(*key), gfp | __GFP_ZERO);
1186 if (!key)
1187 return -ENOMEM;
1188 if (!tcp_alloc_md5sig_pool()) {
1189 sock_kfree_s(sk, key, sizeof(*key));
1190 return -ENOMEM;
1191 }
1192
1193 memcpy(key->key, newkey, newkeylen);
1194 key->keylen = newkeylen;
1195 key->family = family;
1196 key->prefixlen = prefixlen;
1197 key->l3index = l3index;
1198 memcpy(&key->addr, addr,
1199 (family == AF_INET6) ? sizeof(struct in6_addr) :
1200 sizeof(struct in_addr));
1201 hlist_add_head_rcu(&key->node, &md5sig->head);
1202 return 0;
1203}
1204EXPORT_SYMBOL(tcp_md5_do_add);
1205
1206int tcp_md5_do_del(struct sock *sk, const union tcp_md5_addr *addr, int family,
1207 u8 prefixlen, int l3index)
1208{
1209 struct tcp_md5sig_key *key;
1210
1211 key = tcp_md5_do_lookup_exact(sk, addr, family, prefixlen, l3index);
1212 if (!key)
1213 return -ENOENT;
1214 hlist_del_rcu(&key->node);
1215 atomic_sub(sizeof(*key), &sk->sk_omem_alloc);
1216 kfree_rcu(key, rcu);
1217 return 0;
1218}
1219EXPORT_SYMBOL(tcp_md5_do_del);
1220
1221static void tcp_clear_md5_list(struct sock *sk)
1222{
1223 struct tcp_sock *tp = tcp_sk(sk);
1224 struct tcp_md5sig_key *key;
1225 struct hlist_node *n;
1226 struct tcp_md5sig_info *md5sig;
1227
1228 md5sig = rcu_dereference_protected(tp->md5sig_info, 1);
1229
1230 hlist_for_each_entry_safe(key, n, &md5sig->head, node) {
1231 hlist_del_rcu(&key->node);
1232 atomic_sub(sizeof(*key), &sk->sk_omem_alloc);
1233 kfree_rcu(key, rcu);
1234 }
1235}
1236
1237static int tcp_v4_parse_md5_keys(struct sock *sk, int optname,
1238 sockptr_t optval, int optlen)
1239{
1240 struct tcp_md5sig cmd;
1241 struct sockaddr_in *sin = (struct sockaddr_in *)&cmd.tcpm_addr;
1242 const union tcp_md5_addr *addr;
1243 u8 prefixlen = 32;
1244 int l3index = 0;
1245
1246 if (optlen < sizeof(cmd))
1247 return -EINVAL;
1248
1249 if (copy_from_sockptr(&cmd, optval, sizeof(cmd)))
1250 return -EFAULT;
1251
1252 if (sin->sin_family != AF_INET)
1253 return -EINVAL;
1254
1255 if (optname == TCP_MD5SIG_EXT &&
1256 cmd.tcpm_flags & TCP_MD5SIG_FLAG_PREFIX) {
1257 prefixlen = cmd.tcpm_prefixlen;
1258 if (prefixlen > 32)
1259 return -EINVAL;
1260 }
1261
1262 if (optname == TCP_MD5SIG_EXT &&
1263 cmd.tcpm_flags & TCP_MD5SIG_FLAG_IFINDEX) {
1264 struct net_device *dev;
1265
1266 rcu_read_lock();
1267 dev = dev_get_by_index_rcu(sock_net(sk), cmd.tcpm_ifindex);
1268 if (dev && netif_is_l3_master(dev))
1269 l3index = dev->ifindex;
1270
1271 rcu_read_unlock();
1272
1273 /* ok to reference set/not set outside of rcu;
1274 * right now device MUST be an L3 master
1275 */
1276 if (!dev || !l3index)
1277 return -EINVAL;
1278 }
1279
1280 addr = (union tcp_md5_addr *)&sin->sin_addr.s_addr;
1281
1282 if (!cmd.tcpm_keylen)
1283 return tcp_md5_do_del(sk, addr, AF_INET, prefixlen, l3index);
1284
1285 if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN)
1286 return -EINVAL;
1287
1288 return tcp_md5_do_add(sk, addr, AF_INET, prefixlen, l3index,
1289 cmd.tcpm_key, cmd.tcpm_keylen, GFP_KERNEL);
1290}
1291
1292static int tcp_v4_md5_hash_headers(struct tcp_md5sig_pool *hp,
1293 __be32 daddr, __be32 saddr,
1294 const struct tcphdr *th, int nbytes)
1295{
1296 struct tcp4_pseudohdr *bp;
1297 struct scatterlist sg;
1298 struct tcphdr *_th;
1299
1300 bp = hp->scratch;
1301 bp->saddr = saddr;
1302 bp->daddr = daddr;
1303 bp->pad = 0;
1304 bp->protocol = IPPROTO_TCP;
1305 bp->len = cpu_to_be16(nbytes);
1306
1307 _th = (struct tcphdr *)(bp + 1);
1308 memcpy(_th, th, sizeof(*th));
1309 _th->check = 0;
1310
1311 sg_init_one(&sg, bp, sizeof(*bp) + sizeof(*th));
1312 ahash_request_set_crypt(hp->md5_req, &sg, NULL,
1313 sizeof(*bp) + sizeof(*th));
1314 return crypto_ahash_update(hp->md5_req);
1315}
1316
1317static int tcp_v4_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key,
1318 __be32 daddr, __be32 saddr, const struct tcphdr *th)
1319{
1320 struct tcp_md5sig_pool *hp;
1321 struct ahash_request *req;
1322
1323 hp = tcp_get_md5sig_pool();
1324 if (!hp)
1325 goto clear_hash_noput;
1326 req = hp->md5_req;
1327
1328 if (crypto_ahash_init(req))
1329 goto clear_hash;
1330 if (tcp_v4_md5_hash_headers(hp, daddr, saddr, th, th->doff << 2))
1331 goto clear_hash;
1332 if (tcp_md5_hash_key(hp, key))
1333 goto clear_hash;
1334 ahash_request_set_crypt(req, NULL, md5_hash, 0);
1335 if (crypto_ahash_final(req))
1336 goto clear_hash;
1337
1338 tcp_put_md5sig_pool();
1339 return 0;
1340
1341clear_hash:
1342 tcp_put_md5sig_pool();
1343clear_hash_noput:
1344 memset(md5_hash, 0, 16);
1345 return 1;
1346}
1347
1348int tcp_v4_md5_hash_skb(char *md5_hash, const struct tcp_md5sig_key *key,
1349 const struct sock *sk,
1350 const struct sk_buff *skb)
1351{
1352 struct tcp_md5sig_pool *hp;
1353 struct ahash_request *req;
1354 const struct tcphdr *th = tcp_hdr(skb);
1355 __be32 saddr, daddr;
1356
1357 if (sk) { /* valid for establish/request sockets */
1358 saddr = sk->sk_rcv_saddr;
1359 daddr = sk->sk_daddr;
1360 } else {
1361 const struct iphdr *iph = ip_hdr(skb);
1362 saddr = iph->saddr;
1363 daddr = iph->daddr;
1364 }
1365
1366 hp = tcp_get_md5sig_pool();
1367 if (!hp)
1368 goto clear_hash_noput;
1369 req = hp->md5_req;
1370
1371 if (crypto_ahash_init(req))
1372 goto clear_hash;
1373
1374 if (tcp_v4_md5_hash_headers(hp, daddr, saddr, th, skb->len))
1375 goto clear_hash;
1376 if (tcp_md5_hash_skb_data(hp, skb, th->doff << 2))
1377 goto clear_hash;
1378 if (tcp_md5_hash_key(hp, key))
1379 goto clear_hash;
1380 ahash_request_set_crypt(req, NULL, md5_hash, 0);
1381 if (crypto_ahash_final(req))
1382 goto clear_hash;
1383
1384 tcp_put_md5sig_pool();
1385 return 0;
1386
1387clear_hash:
1388 tcp_put_md5sig_pool();
1389clear_hash_noput:
1390 memset(md5_hash, 0, 16);
1391 return 1;
1392}
1393EXPORT_SYMBOL(tcp_v4_md5_hash_skb);
1394
1395#endif
1396
1397/* Called with rcu_read_lock() */
1398static bool tcp_v4_inbound_md5_hash(const struct sock *sk,
1399 const struct sk_buff *skb,
1400 int dif, int sdif)
1401{
1402#ifdef CONFIG_TCP_MD5SIG
1403 /*
1404 * This gets called for each TCP segment that arrives
1405 * so we want to be efficient.
1406 * We have 3 drop cases:
1407 * o No MD5 hash and one expected.
1408 * o MD5 hash and we're not expecting one.
1409 * o MD5 hash and its wrong.
1410 */
1411 const __u8 *hash_location = NULL;
1412 struct tcp_md5sig_key *hash_expected;
1413 const struct iphdr *iph = ip_hdr(skb);
1414 const struct tcphdr *th = tcp_hdr(skb);
1415 const union tcp_md5_addr *addr;
1416 unsigned char newhash[16];
1417 int genhash, l3index;
1418
1419 /* sdif set, means packet ingressed via a device
1420 * in an L3 domain and dif is set to the l3mdev
1421 */
1422 l3index = sdif ? dif : 0;
1423
1424 addr = (union tcp_md5_addr *)&iph->saddr;
1425 hash_expected = tcp_md5_do_lookup(sk, l3index, addr, AF_INET);
1426 hash_location = tcp_parse_md5sig_option(th);
1427
1428 /* We've parsed the options - do we have a hash? */
1429 if (!hash_expected && !hash_location)
1430 return false;
1431
1432 if (hash_expected && !hash_location) {
1433 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5NOTFOUND);
1434 return true;
1435 }
1436
1437 if (!hash_expected && hash_location) {
1438 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5UNEXPECTED);
1439 return true;
1440 }
1441
1442 /* Okay, so this is hash_expected and hash_location -
1443 * so we need to calculate the checksum.
1444 */
1445 genhash = tcp_v4_md5_hash_skb(newhash,
1446 hash_expected,
1447 NULL, skb);
1448
1449 if (genhash || memcmp(hash_location, newhash, 16) != 0) {
1450 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5FAILURE);
1451 net_info_ratelimited("MD5 Hash failed for (%pI4, %d)->(%pI4, %d)%s L3 index %d\n",
1452 &iph->saddr, ntohs(th->source),
1453 &iph->daddr, ntohs(th->dest),
1454 genhash ? " tcp_v4_calc_md5_hash failed"
1455 : "", l3index);
1456 return true;
1457 }
1458 return false;
1459#endif
1460 return false;
1461}
1462
1463static void tcp_v4_init_req(struct request_sock *req,
1464 const struct sock *sk_listener,
1465 struct sk_buff *skb)
1466{
1467 struct inet_request_sock *ireq = inet_rsk(req);
1468 struct net *net = sock_net(sk_listener);
1469
1470 sk_rcv_saddr_set(req_to_sk(req), ip_hdr(skb)->daddr);
1471 sk_daddr_set(req_to_sk(req), ip_hdr(skb)->saddr);
1472 RCU_INIT_POINTER(ireq->ireq_opt, tcp_v4_save_options(net, skb));
1473}
1474
1475static struct dst_entry *tcp_v4_route_req(const struct sock *sk,
1476 struct sk_buff *skb,
1477 struct flowi *fl,
1478 struct request_sock *req)
1479{
1480 tcp_v4_init_req(req, sk, skb);
1481
1482 if (security_inet_conn_request(sk, skb, req))
1483 return NULL;
1484
1485 return inet_csk_route_req(sk, &fl->u.ip4, req);
1486}
1487
1488struct request_sock_ops tcp_request_sock_ops __read_mostly = {
1489 .family = PF_INET,
1490 .obj_size = sizeof(struct tcp_request_sock),
1491 .rtx_syn_ack = tcp_rtx_synack,
1492 .send_ack = tcp_v4_reqsk_send_ack,
1493 .destructor = tcp_v4_reqsk_destructor,
1494 .send_reset = tcp_v4_send_reset,
1495 .syn_ack_timeout = tcp_syn_ack_timeout,
1496};
1497
1498const struct tcp_request_sock_ops tcp_request_sock_ipv4_ops = {
1499 .mss_clamp = TCP_MSS_DEFAULT,
1500#ifdef CONFIG_TCP_MD5SIG
1501 .req_md5_lookup = tcp_v4_md5_lookup,
1502 .calc_md5_hash = tcp_v4_md5_hash_skb,
1503#endif
1504#ifdef CONFIG_SYN_COOKIES
1505 .cookie_init_seq = cookie_v4_init_sequence,
1506#endif
1507 .route_req = tcp_v4_route_req,
1508 .init_seq = tcp_v4_init_seq,
1509 .init_ts_off = tcp_v4_init_ts_off,
1510 .send_synack = tcp_v4_send_synack,
1511};
1512
1513int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
1514{
1515 /* Never answer to SYNs send to broadcast or multicast */
1516 if (skb_rtable(skb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
1517 goto drop;
1518
1519 return tcp_conn_request(&tcp_request_sock_ops,
1520 &tcp_request_sock_ipv4_ops, sk, skb);
1521
1522drop:
1523 tcp_listendrop(sk);
1524 return 0;
1525}
1526EXPORT_SYMBOL(tcp_v4_conn_request);
1527
1528
1529/*
1530 * The three way handshake has completed - we got a valid synack -
1531 * now create the new socket.
1532 */
1533struct sock *tcp_v4_syn_recv_sock(const struct sock *sk, struct sk_buff *skb,
1534 struct request_sock *req,
1535 struct dst_entry *dst,
1536 struct request_sock *req_unhash,
1537 bool *own_req)
1538{
1539 struct inet_request_sock *ireq;
1540 bool found_dup_sk = false;
1541 struct inet_sock *newinet;
1542 struct tcp_sock *newtp;
1543 struct sock *newsk;
1544#ifdef CONFIG_TCP_MD5SIG
1545 const union tcp_md5_addr *addr;
1546 struct tcp_md5sig_key *key;
1547 int l3index;
1548#endif
1549 struct ip_options_rcu *inet_opt;
1550
1551 if (sk_acceptq_is_full(sk))
1552 goto exit_overflow;
1553
1554 newsk = tcp_create_openreq_child(sk, req, skb);
1555 if (!newsk)
1556 goto exit_nonewsk;
1557
1558 newsk->sk_gso_type = SKB_GSO_TCPV4;
1559 inet_sk_rx_dst_set(newsk, skb);
1560
1561 newtp = tcp_sk(newsk);
1562 newinet = inet_sk(newsk);
1563 ireq = inet_rsk(req);
1564 sk_daddr_set(newsk, ireq->ir_rmt_addr);
1565 sk_rcv_saddr_set(newsk, ireq->ir_loc_addr);
1566 newsk->sk_bound_dev_if = ireq->ir_iif;
1567 newinet->inet_saddr = ireq->ir_loc_addr;
1568 inet_opt = rcu_dereference(ireq->ireq_opt);
1569 RCU_INIT_POINTER(newinet->inet_opt, inet_opt);
1570 newinet->mc_index = inet_iif(skb);
1571 newinet->mc_ttl = ip_hdr(skb)->ttl;
1572 newinet->rcv_tos = ip_hdr(skb)->tos;
1573 inet_csk(newsk)->icsk_ext_hdr_len = 0;
1574 if (inet_opt)
1575 inet_csk(newsk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
1576 newinet->inet_id = prandom_u32();
1577
1578 /* Set ToS of the new socket based upon the value of incoming SYN.
1579 * ECT bits are set later in tcp_init_transfer().
1580 */
1581 if (sock_net(sk)->ipv4.sysctl_tcp_reflect_tos)
1582 newinet->tos = tcp_rsk(req)->syn_tos & ~INET_ECN_MASK;
1583
1584 if (!dst) {
1585 dst = inet_csk_route_child_sock(sk, newsk, req);
1586 if (!dst)
1587 goto put_and_exit;
1588 } else {
1589 /* syncookie case : see end of cookie_v4_check() */
1590 }
1591 sk_setup_caps(newsk, dst);
1592
1593 tcp_ca_openreq_child(newsk, dst);
1594
1595 tcp_sync_mss(newsk, dst_mtu(dst));
1596 newtp->advmss = tcp_mss_clamp(tcp_sk(sk), dst_metric_advmss(dst));
1597
1598 tcp_initialize_rcv_mss(newsk);
1599
1600#ifdef CONFIG_TCP_MD5SIG
1601 l3index = l3mdev_master_ifindex_by_index(sock_net(sk), ireq->ir_iif);
1602 /* Copy over the MD5 key from the original socket */
1603 addr = (union tcp_md5_addr *)&newinet->inet_daddr;
1604 key = tcp_md5_do_lookup(sk, l3index, addr, AF_INET);
1605 if (key) {
1606 /*
1607 * We're using one, so create a matching key
1608 * on the newsk structure. If we fail to get
1609 * memory, then we end up not copying the key
1610 * across. Shucks.
1611 */
1612 tcp_md5_do_add(newsk, addr, AF_INET, 32, l3index,
1613 key->key, key->keylen, GFP_ATOMIC);
1614 sk_nocaps_add(newsk, NETIF_F_GSO_MASK);
1615 }
1616#endif
1617
1618 if (__inet_inherit_port(sk, newsk) < 0)
1619 goto put_and_exit;
1620 *own_req = inet_ehash_nolisten(newsk, req_to_sk(req_unhash),
1621 &found_dup_sk);
1622 if (likely(*own_req)) {
1623 tcp_move_syn(newtp, req);
1624 ireq->ireq_opt = NULL;
1625 } else {
1626 newinet->inet_opt = NULL;
1627
1628 if (!req_unhash && found_dup_sk) {
1629 /* This code path should only be executed in the
1630 * syncookie case only
1631 */
1632 bh_unlock_sock(newsk);
1633 sock_put(newsk);
1634 newsk = NULL;
1635 }
1636 }
1637 return newsk;
1638
1639exit_overflow:
1640 NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
1641exit_nonewsk:
1642 dst_release(dst);
1643exit:
1644 tcp_listendrop(sk);
1645 return NULL;
1646put_and_exit:
1647 newinet->inet_opt = NULL;
1648 inet_csk_prepare_forced_close(newsk);
1649 tcp_done(newsk);
1650 goto exit;
1651}
1652EXPORT_SYMBOL(tcp_v4_syn_recv_sock);
1653
1654static struct sock *tcp_v4_cookie_check(struct sock *sk, struct sk_buff *skb)
1655{
1656#ifdef CONFIG_SYN_COOKIES
1657 const struct tcphdr *th = tcp_hdr(skb);
1658
1659 if (!th->syn)
1660 sk = cookie_v4_check(sk, skb);
1661#endif
1662 return sk;
1663}
1664
1665u16 tcp_v4_get_syncookie(struct sock *sk, struct iphdr *iph,
1666 struct tcphdr *th, u32 *cookie)
1667{
1668 u16 mss = 0;
1669#ifdef CONFIG_SYN_COOKIES
1670 mss = tcp_get_syncookie_mss(&tcp_request_sock_ops,
1671 &tcp_request_sock_ipv4_ops, sk, th);
1672 if (mss) {
1673 *cookie = __cookie_v4_init_sequence(iph, th, &mss);
1674 tcp_synq_overflow(sk);
1675 }
1676#endif
1677 return mss;
1678}
1679
1680INDIRECT_CALLABLE_DECLARE(struct dst_entry *ipv4_dst_check(struct dst_entry *,
1681 u32));
1682/* The socket must have it's spinlock held when we get
1683 * here, unless it is a TCP_LISTEN socket.
1684 *
1685 * We have a potential double-lock case here, so even when
1686 * doing backlog processing we use the BH locking scheme.
1687 * This is because we cannot sleep with the original spinlock
1688 * held.
1689 */
1690int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
1691{
1692 struct sock *rsk;
1693
1694 if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
1695 struct dst_entry *dst = sk->sk_rx_dst;
1696
1697 sock_rps_save_rxhash(sk, skb);
1698 sk_mark_napi_id(sk, skb);
1699 if (dst) {
1700 if (inet_sk(sk)->rx_dst_ifindex != skb->skb_iif ||
1701 !INDIRECT_CALL_1(dst->ops->check, ipv4_dst_check,
1702 dst, 0)) {
1703 dst_release(dst);
1704 sk->sk_rx_dst = NULL;
1705 }
1706 }
1707 tcp_rcv_established(sk, skb);
1708 return 0;
1709 }
1710
1711 if (tcp_checksum_complete(skb))
1712 goto csum_err;
1713
1714 if (sk->sk_state == TCP_LISTEN) {
1715 struct sock *nsk = tcp_v4_cookie_check(sk, skb);
1716
1717 if (!nsk)
1718 goto discard;
1719 if (nsk != sk) {
1720 if (tcp_child_process(sk, nsk, skb)) {
1721 rsk = nsk;
1722 goto reset;
1723 }
1724 return 0;
1725 }
1726 } else
1727 sock_rps_save_rxhash(sk, skb);
1728
1729 if (tcp_rcv_state_process(sk, skb)) {
1730 rsk = sk;
1731 goto reset;
1732 }
1733 return 0;
1734
1735reset:
1736 tcp_v4_send_reset(rsk, skb);
1737discard:
1738 kfree_skb(skb);
1739 /* Be careful here. If this function gets more complicated and
1740 * gcc suffers from register pressure on the x86, sk (in %ebx)
1741 * might be destroyed here. This current version compiles correctly,
1742 * but you have been warned.
1743 */
1744 return 0;
1745
1746csum_err:
1747 trace_tcp_bad_csum(skb);
1748 TCP_INC_STATS(sock_net(sk), TCP_MIB_CSUMERRORS);
1749 TCP_INC_STATS(sock_net(sk), TCP_MIB_INERRS);
1750 goto discard;
1751}
1752EXPORT_SYMBOL(tcp_v4_do_rcv);
1753
1754int tcp_v4_early_demux(struct sk_buff *skb)
1755{
1756 const struct iphdr *iph;
1757 const struct tcphdr *th;
1758 struct sock *sk;
1759
1760 if (skb->pkt_type != PACKET_HOST)
1761 return 0;
1762
1763 if (!pskb_may_pull(skb, skb_transport_offset(skb) + sizeof(struct tcphdr)))
1764 return 0;
1765
1766 iph = ip_hdr(skb);
1767 th = tcp_hdr(skb);
1768
1769 if (th->doff < sizeof(struct tcphdr) / 4)
1770 return 0;
1771
1772 sk = __inet_lookup_established(dev_net(skb->dev), &tcp_hashinfo,
1773 iph->saddr, th->source,
1774 iph->daddr, ntohs(th->dest),
1775 skb->skb_iif, inet_sdif(skb));
1776 if (sk) {
1777 skb->sk = sk;
1778 skb->destructor = sock_edemux;
1779 if (sk_fullsock(sk)) {
1780 struct dst_entry *dst = READ_ONCE(sk->sk_rx_dst);
1781
1782 if (dst)
1783 dst = dst_check(dst, 0);
1784 if (dst &&
1785 inet_sk(sk)->rx_dst_ifindex == skb->skb_iif)
1786 skb_dst_set_noref(skb, dst);
1787 }
1788 }
1789 return 0;
1790}
1791
1792bool tcp_add_backlog(struct sock *sk, struct sk_buff *skb)
1793{
1794 u32 limit = READ_ONCE(sk->sk_rcvbuf) + READ_ONCE(sk->sk_sndbuf);
1795 u32 tail_gso_size, tail_gso_segs;
1796 struct skb_shared_info *shinfo;
1797 const struct tcphdr *th;
1798 struct tcphdr *thtail;
1799 struct sk_buff *tail;
1800 unsigned int hdrlen;
1801 bool fragstolen;
1802 u32 gso_segs;
1803 u32 gso_size;
1804 int delta;
1805
1806 /* In case all data was pulled from skb frags (in __pskb_pull_tail()),
1807 * we can fix skb->truesize to its real value to avoid future drops.
1808 * This is valid because skb is not yet charged to the socket.
1809 * It has been noticed pure SACK packets were sometimes dropped
1810 * (if cooked by drivers without copybreak feature).
1811 */
1812 skb_condense(skb);
1813
1814 skb_dst_drop(skb);
1815
1816 if (unlikely(tcp_checksum_complete(skb))) {
1817 bh_unlock_sock(sk);
1818 trace_tcp_bad_csum(skb);
1819 __TCP_INC_STATS(sock_net(sk), TCP_MIB_CSUMERRORS);
1820 __TCP_INC_STATS(sock_net(sk), TCP_MIB_INERRS);
1821 return true;
1822 }
1823
1824 /* Attempt coalescing to last skb in backlog, even if we are
1825 * above the limits.
1826 * This is okay because skb capacity is limited to MAX_SKB_FRAGS.
1827 */
1828 th = (const struct tcphdr *)skb->data;
1829 hdrlen = th->doff * 4;
1830
1831 tail = sk->sk_backlog.tail;
1832 if (!tail)
1833 goto no_coalesce;
1834 thtail = (struct tcphdr *)tail->data;
1835
1836 if (TCP_SKB_CB(tail)->end_seq != TCP_SKB_CB(skb)->seq ||
1837 TCP_SKB_CB(tail)->ip_dsfield != TCP_SKB_CB(skb)->ip_dsfield ||
1838 ((TCP_SKB_CB(tail)->tcp_flags |
1839 TCP_SKB_CB(skb)->tcp_flags) & (TCPHDR_SYN | TCPHDR_RST | TCPHDR_URG)) ||
1840 !((TCP_SKB_CB(tail)->tcp_flags &
1841 TCP_SKB_CB(skb)->tcp_flags) & TCPHDR_ACK) ||
1842 ((TCP_SKB_CB(tail)->tcp_flags ^
1843 TCP_SKB_CB(skb)->tcp_flags) & (TCPHDR_ECE | TCPHDR_CWR)) ||
1844#ifdef CONFIG_TLS_DEVICE
1845 tail->decrypted != skb->decrypted ||
1846#endif
1847 thtail->doff != th->doff ||
1848 memcmp(thtail + 1, th + 1, hdrlen - sizeof(*th)))
1849 goto no_coalesce;
1850
1851 __skb_pull(skb, hdrlen);
1852
1853 shinfo = skb_shinfo(skb);
1854 gso_size = shinfo->gso_size ?: skb->len;
1855 gso_segs = shinfo->gso_segs ?: 1;
1856
1857 shinfo = skb_shinfo(tail);
1858 tail_gso_size = shinfo->gso_size ?: (tail->len - hdrlen);
1859 tail_gso_segs = shinfo->gso_segs ?: 1;
1860
1861 if (skb_try_coalesce(tail, skb, &fragstolen, &delta)) {
1862 TCP_SKB_CB(tail)->end_seq = TCP_SKB_CB(skb)->end_seq;
1863
1864 if (likely(!before(TCP_SKB_CB(skb)->ack_seq, TCP_SKB_CB(tail)->ack_seq))) {
1865 TCP_SKB_CB(tail)->ack_seq = TCP_SKB_CB(skb)->ack_seq;
1866 thtail->window = th->window;
1867 }
1868
1869 /* We have to update both TCP_SKB_CB(tail)->tcp_flags and
1870 * thtail->fin, so that the fast path in tcp_rcv_established()
1871 * is not entered if we append a packet with a FIN.
1872 * SYN, RST, URG are not present.
1873 * ACK is set on both packets.
1874 * PSH : we do not really care in TCP stack,
1875 * at least for 'GRO' packets.
1876 */
1877 thtail->fin |= th->fin;
1878 TCP_SKB_CB(tail)->tcp_flags |= TCP_SKB_CB(skb)->tcp_flags;
1879
1880 if (TCP_SKB_CB(skb)->has_rxtstamp) {
1881 TCP_SKB_CB(tail)->has_rxtstamp = true;
1882 tail->tstamp = skb->tstamp;
1883 skb_hwtstamps(tail)->hwtstamp = skb_hwtstamps(skb)->hwtstamp;
1884 }
1885
1886 /* Not as strict as GRO. We only need to carry mss max value */
1887 shinfo->gso_size = max(gso_size, tail_gso_size);
1888 shinfo->gso_segs = min_t(u32, gso_segs + tail_gso_segs, 0xFFFF);
1889
1890 sk->sk_backlog.len += delta;
1891 __NET_INC_STATS(sock_net(sk),
1892 LINUX_MIB_TCPBACKLOGCOALESCE);
1893 kfree_skb_partial(skb, fragstolen);
1894 return false;
1895 }
1896 __skb_push(skb, hdrlen);
1897
1898no_coalesce:
1899 /* Only socket owner can try to collapse/prune rx queues
1900 * to reduce memory overhead, so add a little headroom here.
1901 * Few sockets backlog are possibly concurrently non empty.
1902 */
1903 limit += 64*1024;
1904
1905 if (unlikely(sk_add_backlog(sk, skb, limit))) {
1906 bh_unlock_sock(sk);
1907 __NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPBACKLOGDROP);
1908 return true;
1909 }
1910 return false;
1911}
1912EXPORT_SYMBOL(tcp_add_backlog);
1913
1914int tcp_filter(struct sock *sk, struct sk_buff *skb)
1915{
1916 struct tcphdr *th = (struct tcphdr *)skb->data;
1917
1918 return sk_filter_trim_cap(sk, skb, th->doff * 4);
1919}
1920EXPORT_SYMBOL(tcp_filter);
1921
1922static void tcp_v4_restore_cb(struct sk_buff *skb)
1923{
1924 memmove(IPCB(skb), &TCP_SKB_CB(skb)->header.h4,
1925 sizeof(struct inet_skb_parm));
1926}
1927
1928static void tcp_v4_fill_cb(struct sk_buff *skb, const struct iphdr *iph,
1929 const struct tcphdr *th)
1930{
1931 /* This is tricky : We move IPCB at its correct location into TCP_SKB_CB()
1932 * barrier() makes sure compiler wont play fool^Waliasing games.
1933 */
1934 memmove(&TCP_SKB_CB(skb)->header.h4, IPCB(skb),
1935 sizeof(struct inet_skb_parm));
1936 barrier();
1937
1938 TCP_SKB_CB(skb)->seq = ntohl(th->seq);
1939 TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
1940 skb->len - th->doff * 4);
1941 TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
1942 TCP_SKB_CB(skb)->tcp_flags = tcp_flag_byte(th);
1943 TCP_SKB_CB(skb)->tcp_tw_isn = 0;
1944 TCP_SKB_CB(skb)->ip_dsfield = ipv4_get_dsfield(iph);
1945 TCP_SKB_CB(skb)->sacked = 0;
1946 TCP_SKB_CB(skb)->has_rxtstamp =
1947 skb->tstamp || skb_hwtstamps(skb)->hwtstamp;
1948}
1949
1950/*
1951 * From tcp_input.c
1952 */
1953
1954int tcp_v4_rcv(struct sk_buff *skb)
1955{
1956 struct net *net = dev_net(skb->dev);
1957 struct sk_buff *skb_to_free;
1958 int sdif = inet_sdif(skb);
1959 int dif = inet_iif(skb);
1960 const struct iphdr *iph;
1961 const struct tcphdr *th;
1962 bool refcounted;
1963 struct sock *sk;
1964 int ret;
1965
1966 if (skb->pkt_type != PACKET_HOST)
1967 goto discard_it;
1968
1969 /* Count it even if it's bad */
1970 __TCP_INC_STATS(net, TCP_MIB_INSEGS);
1971
1972 if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
1973 goto discard_it;
1974
1975 th = (const struct tcphdr *)skb->data;
1976
1977 if (unlikely(th->doff < sizeof(struct tcphdr) / 4))
1978 goto bad_packet;
1979 if (!pskb_may_pull(skb, th->doff * 4))
1980 goto discard_it;
1981
1982 /* An explanation is required here, I think.
1983 * Packet length and doff are validated by header prediction,
1984 * provided case of th->doff==0 is eliminated.
1985 * So, we defer the checks. */
1986
1987 if (skb_checksum_init(skb, IPPROTO_TCP, inet_compute_pseudo))
1988 goto csum_error;
1989
1990 th = (const struct tcphdr *)skb->data;
1991 iph = ip_hdr(skb);
1992lookup:
1993 sk = __inet_lookup_skb(&tcp_hashinfo, skb, __tcp_hdrlen(th), th->source,
1994 th->dest, sdif, &refcounted);
1995 if (!sk)
1996 goto no_tcp_socket;
1997
1998process:
1999 if (sk->sk_state == TCP_TIME_WAIT)
2000 goto do_time_wait;
2001
2002 if (sk->sk_state == TCP_NEW_SYN_RECV) {
2003 struct request_sock *req = inet_reqsk(sk);
2004 bool req_stolen = false;
2005 struct sock *nsk;
2006
2007 sk = req->rsk_listener;
2008 if (unlikely(tcp_v4_inbound_md5_hash(sk, skb, dif, sdif))) {
2009 sk_drops_add(sk, skb);
2010 reqsk_put(req);
2011 goto discard_it;
2012 }
2013 if (tcp_checksum_complete(skb)) {
2014 reqsk_put(req);
2015 goto csum_error;
2016 }
2017 if (unlikely(sk->sk_state != TCP_LISTEN)) {
2018 nsk = reuseport_migrate_sock(sk, req_to_sk(req), skb);
2019 if (!nsk) {
2020 inet_csk_reqsk_queue_drop_and_put(sk, req);
2021 goto lookup;
2022 }
2023 sk = nsk;
2024 /* reuseport_migrate_sock() has already held one sk_refcnt
2025 * before returning.
2026 */
2027 } else {
2028 /* We own a reference on the listener, increase it again
2029 * as we might lose it too soon.
2030 */
2031 sock_hold(sk);
2032 }
2033 refcounted = true;
2034 nsk = NULL;
2035 if (!tcp_filter(sk, skb)) {
2036 th = (const struct tcphdr *)skb->data;
2037 iph = ip_hdr(skb);
2038 tcp_v4_fill_cb(skb, iph, th);
2039 nsk = tcp_check_req(sk, skb, req, false, &req_stolen);
2040 }
2041 if (!nsk) {
2042 reqsk_put(req);
2043 if (req_stolen) {
2044 /* Another cpu got exclusive access to req
2045 * and created a full blown socket.
2046 * Try to feed this packet to this socket
2047 * instead of discarding it.
2048 */
2049 tcp_v4_restore_cb(skb);
2050 sock_put(sk);
2051 goto lookup;
2052 }
2053 goto discard_and_relse;
2054 }
2055 if (nsk == sk) {
2056 reqsk_put(req);
2057 tcp_v4_restore_cb(skb);
2058 } else if (tcp_child_process(sk, nsk, skb)) {
2059 tcp_v4_send_reset(nsk, skb);
2060 goto discard_and_relse;
2061 } else {
2062 sock_put(sk);
2063 return 0;
2064 }
2065 }
2066 if (unlikely(iph->ttl < inet_sk(sk)->min_ttl)) {
2067 __NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP);
2068 goto discard_and_relse;
2069 }
2070
2071 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
2072 goto discard_and_relse;
2073
2074 if (tcp_v4_inbound_md5_hash(sk, skb, dif, sdif))
2075 goto discard_and_relse;
2076
2077 nf_reset_ct(skb);
2078
2079 if (tcp_filter(sk, skb))
2080 goto discard_and_relse;
2081 th = (const struct tcphdr *)skb->data;
2082 iph = ip_hdr(skb);
2083 tcp_v4_fill_cb(skb, iph, th);
2084
2085 skb->dev = NULL;
2086
2087 if (sk->sk_state == TCP_LISTEN) {
2088 ret = tcp_v4_do_rcv(sk, skb);
2089 goto put_and_return;
2090 }
2091
2092 sk_incoming_cpu_update(sk);
2093
2094 bh_lock_sock_nested(sk);
2095 tcp_segs_in(tcp_sk(sk), skb);
2096 ret = 0;
2097 if (!sock_owned_by_user(sk)) {
2098 skb_to_free = sk->sk_rx_skb_cache;
2099 sk->sk_rx_skb_cache = NULL;
2100 ret = tcp_v4_do_rcv(sk, skb);
2101 } else {
2102 if (tcp_add_backlog(sk, skb))
2103 goto discard_and_relse;
2104 skb_to_free = NULL;
2105 }
2106 bh_unlock_sock(sk);
2107 if (skb_to_free)
2108 __kfree_skb(skb_to_free);
2109
2110put_and_return:
2111 if (refcounted)
2112 sock_put(sk);
2113
2114 return ret;
2115
2116no_tcp_socket:
2117 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
2118 goto discard_it;
2119
2120 tcp_v4_fill_cb(skb, iph, th);
2121
2122 if (tcp_checksum_complete(skb)) {
2123csum_error:
2124 trace_tcp_bad_csum(skb);
2125 __TCP_INC_STATS(net, TCP_MIB_CSUMERRORS);
2126bad_packet:
2127 __TCP_INC_STATS(net, TCP_MIB_INERRS);
2128 } else {
2129 tcp_v4_send_reset(NULL, skb);
2130 }
2131
2132discard_it:
2133 /* Discard frame. */
2134 kfree_skb(skb);
2135 return 0;
2136
2137discard_and_relse:
2138 sk_drops_add(sk, skb);
2139 if (refcounted)
2140 sock_put(sk);
2141 goto discard_it;
2142
2143do_time_wait:
2144 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
2145 inet_twsk_put(inet_twsk(sk));
2146 goto discard_it;
2147 }
2148
2149 tcp_v4_fill_cb(skb, iph, th);
2150
2151 if (tcp_checksum_complete(skb)) {
2152 inet_twsk_put(inet_twsk(sk));
2153 goto csum_error;
2154 }
2155 switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) {
2156 case TCP_TW_SYN: {
2157 struct sock *sk2 = inet_lookup_listener(dev_net(skb->dev),
2158 &tcp_hashinfo, skb,
2159 __tcp_hdrlen(th),
2160 iph->saddr, th->source,
2161 iph->daddr, th->dest,
2162 inet_iif(skb),
2163 sdif);
2164 if (sk2) {
2165 inet_twsk_deschedule_put(inet_twsk(sk));
2166 sk = sk2;
2167 tcp_v4_restore_cb(skb);
2168 refcounted = false;
2169 goto process;
2170 }
2171 }
2172 /* to ACK */
2173 fallthrough;
2174 case TCP_TW_ACK:
2175 tcp_v4_timewait_ack(sk, skb);
2176 break;
2177 case TCP_TW_RST:
2178 tcp_v4_send_reset(sk, skb);
2179 inet_twsk_deschedule_put(inet_twsk(sk));
2180 goto discard_it;
2181 case TCP_TW_SUCCESS:;
2182 }
2183 goto discard_it;
2184}
2185
2186static struct timewait_sock_ops tcp_timewait_sock_ops = {
2187 .twsk_obj_size = sizeof(struct tcp_timewait_sock),
2188 .twsk_unique = tcp_twsk_unique,
2189 .twsk_destructor= tcp_twsk_destructor,
2190};
2191
2192void inet_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb)
2193{
2194 struct dst_entry *dst = skb_dst(skb);
2195
2196 if (dst && dst_hold_safe(dst)) {
2197 sk->sk_rx_dst = dst;
2198 inet_sk(sk)->rx_dst_ifindex = skb->skb_iif;
2199 }
2200}
2201EXPORT_SYMBOL(inet_sk_rx_dst_set);
2202
2203const struct inet_connection_sock_af_ops ipv4_specific = {
2204 .queue_xmit = ip_queue_xmit,
2205 .send_check = tcp_v4_send_check,
2206 .rebuild_header = inet_sk_rebuild_header,
2207 .sk_rx_dst_set = inet_sk_rx_dst_set,
2208 .conn_request = tcp_v4_conn_request,
2209 .syn_recv_sock = tcp_v4_syn_recv_sock,
2210 .net_header_len = sizeof(struct iphdr),
2211 .setsockopt = ip_setsockopt,
2212 .getsockopt = ip_getsockopt,
2213 .addr2sockaddr = inet_csk_addr2sockaddr,
2214 .sockaddr_len = sizeof(struct sockaddr_in),
2215 .mtu_reduced = tcp_v4_mtu_reduced,
2216};
2217EXPORT_SYMBOL(ipv4_specific);
2218
2219#ifdef CONFIG_TCP_MD5SIG
2220static const struct tcp_sock_af_ops tcp_sock_ipv4_specific = {
2221 .md5_lookup = tcp_v4_md5_lookup,
2222 .calc_md5_hash = tcp_v4_md5_hash_skb,
2223 .md5_parse = tcp_v4_parse_md5_keys,
2224};
2225#endif
2226
2227/* NOTE: A lot of things set to zero explicitly by call to
2228 * sk_alloc() so need not be done here.
2229 */
2230static int tcp_v4_init_sock(struct sock *sk)
2231{
2232 struct inet_connection_sock *icsk = inet_csk(sk);
2233
2234 tcp_init_sock(sk);
2235
2236 icsk->icsk_af_ops = &ipv4_specific;
2237
2238#ifdef CONFIG_TCP_MD5SIG
2239 tcp_sk(sk)->af_specific = &tcp_sock_ipv4_specific;
2240#endif
2241
2242 return 0;
2243}
2244
2245void tcp_v4_destroy_sock(struct sock *sk)
2246{
2247 struct tcp_sock *tp = tcp_sk(sk);
2248
2249 trace_tcp_destroy_sock(sk);
2250
2251 tcp_clear_xmit_timers(sk);
2252
2253 tcp_cleanup_congestion_control(sk);
2254
2255 tcp_cleanup_ulp(sk);
2256
2257 /* Cleanup up the write buffer. */
2258 tcp_write_queue_purge(sk);
2259
2260 /* Check if we want to disable active TFO */
2261 tcp_fastopen_active_disable_ofo_check(sk);
2262
2263 /* Cleans up our, hopefully empty, out_of_order_queue. */
2264 skb_rbtree_purge(&tp->out_of_order_queue);
2265
2266#ifdef CONFIG_TCP_MD5SIG
2267 /* Clean up the MD5 key list, if any */
2268 if (tp->md5sig_info) {
2269 tcp_clear_md5_list(sk);
2270 kfree_rcu(rcu_dereference_protected(tp->md5sig_info, 1), rcu);
2271 tp->md5sig_info = NULL;
2272 }
2273#endif
2274
2275 /* Clean up a referenced TCP bind bucket. */
2276 if (inet_csk(sk)->icsk_bind_hash)
2277 inet_put_port(sk);
2278
2279 BUG_ON(rcu_access_pointer(tp->fastopen_rsk));
2280
2281 /* If socket is aborted during connect operation */
2282 tcp_free_fastopen_req(tp);
2283 tcp_fastopen_destroy_cipher(sk);
2284 tcp_saved_syn_free(tp);
2285
2286 sk_sockets_allocated_dec(sk);
2287}
2288EXPORT_SYMBOL(tcp_v4_destroy_sock);
2289
2290#ifdef CONFIG_PROC_FS
2291/* Proc filesystem TCP sock list dumping. */
2292
2293/*
2294 * Get next listener socket follow cur. If cur is NULL, get first socket
2295 * starting from bucket given in st->bucket; when st->bucket is zero the
2296 * very first socket in the hash table is returned.
2297 */
2298static void *listening_get_next(struct seq_file *seq, void *cur)
2299{
2300 struct tcp_seq_afinfo *afinfo;
2301 struct tcp_iter_state *st = seq->private;
2302 struct net *net = seq_file_net(seq);
2303 struct inet_listen_hashbucket *ilb;
2304 struct hlist_nulls_node *node;
2305 struct sock *sk = cur;
2306
2307 if (st->bpf_seq_afinfo)
2308 afinfo = st->bpf_seq_afinfo;
2309 else
2310 afinfo = PDE_DATA(file_inode(seq->file));
2311
2312 if (!sk) {
2313get_head:
2314 ilb = &tcp_hashinfo.listening_hash[st->bucket];
2315 spin_lock(&ilb->lock);
2316 sk = sk_nulls_head(&ilb->nulls_head);
2317 st->offset = 0;
2318 goto get_sk;
2319 }
2320 ilb = &tcp_hashinfo.listening_hash[st->bucket];
2321 ++st->num;
2322 ++st->offset;
2323
2324 sk = sk_nulls_next(sk);
2325get_sk:
2326 sk_nulls_for_each_from(sk, node) {
2327 if (!net_eq(sock_net(sk), net))
2328 continue;
2329 if (afinfo->family == AF_UNSPEC ||
2330 sk->sk_family == afinfo->family)
2331 return sk;
2332 }
2333 spin_unlock(&ilb->lock);
2334 st->offset = 0;
2335 if (++st->bucket < INET_LHTABLE_SIZE)
2336 goto get_head;
2337 return NULL;
2338}
2339
2340static void *listening_get_idx(struct seq_file *seq, loff_t *pos)
2341{
2342 struct tcp_iter_state *st = seq->private;
2343 void *rc;
2344
2345 st->bucket = 0;
2346 st->offset = 0;
2347 rc = listening_get_next(seq, NULL);
2348
2349 while (rc && *pos) {
2350 rc = listening_get_next(seq, rc);
2351 --*pos;
2352 }
2353 return rc;
2354}
2355
2356static inline bool empty_bucket(const struct tcp_iter_state *st)
2357{
2358 return hlist_nulls_empty(&tcp_hashinfo.ehash[st->bucket].chain);
2359}
2360
2361/*
2362 * Get first established socket starting from bucket given in st->bucket.
2363 * If st->bucket is zero, the very first socket in the hash is returned.
2364 */
2365static void *established_get_first(struct seq_file *seq)
2366{
2367 struct tcp_seq_afinfo *afinfo;
2368 struct tcp_iter_state *st = seq->private;
2369 struct net *net = seq_file_net(seq);
2370 void *rc = NULL;
2371
2372 if (st->bpf_seq_afinfo)
2373 afinfo = st->bpf_seq_afinfo;
2374 else
2375 afinfo = PDE_DATA(file_inode(seq->file));
2376
2377 st->offset = 0;
2378 for (; st->bucket <= tcp_hashinfo.ehash_mask; ++st->bucket) {
2379 struct sock *sk;
2380 struct hlist_nulls_node *node;
2381 spinlock_t *lock = inet_ehash_lockp(&tcp_hashinfo, st->bucket);
2382
2383 /* Lockless fast path for the common case of empty buckets */
2384 if (empty_bucket(st))
2385 continue;
2386
2387 spin_lock_bh(lock);
2388 sk_nulls_for_each(sk, node, &tcp_hashinfo.ehash[st->bucket].chain) {
2389 if ((afinfo->family != AF_UNSPEC &&
2390 sk->sk_family != afinfo->family) ||
2391 !net_eq(sock_net(sk), net)) {
2392 continue;
2393 }
2394 rc = sk;
2395 goto out;
2396 }
2397 spin_unlock_bh(lock);
2398 }
2399out:
2400 return rc;
2401}
2402
2403static void *established_get_next(struct seq_file *seq, void *cur)
2404{
2405 struct tcp_seq_afinfo *afinfo;
2406 struct sock *sk = cur;
2407 struct hlist_nulls_node *node;
2408 struct tcp_iter_state *st = seq->private;
2409 struct net *net = seq_file_net(seq);
2410
2411 if (st->bpf_seq_afinfo)
2412 afinfo = st->bpf_seq_afinfo;
2413 else
2414 afinfo = PDE_DATA(file_inode(seq->file));
2415
2416 ++st->num;
2417 ++st->offset;
2418
2419 sk = sk_nulls_next(sk);
2420
2421 sk_nulls_for_each_from(sk, node) {
2422 if ((afinfo->family == AF_UNSPEC ||
2423 sk->sk_family == afinfo->family) &&
2424 net_eq(sock_net(sk), net))
2425 return sk;
2426 }
2427
2428 spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
2429 ++st->bucket;
2430 return established_get_first(seq);
2431}
2432
2433static void *established_get_idx(struct seq_file *seq, loff_t pos)
2434{
2435 struct tcp_iter_state *st = seq->private;
2436 void *rc;
2437
2438 st->bucket = 0;
2439 rc = established_get_first(seq);
2440
2441 while (rc && pos) {
2442 rc = established_get_next(seq, rc);
2443 --pos;
2444 }
2445 return rc;
2446}
2447
2448static void *tcp_get_idx(struct seq_file *seq, loff_t pos)
2449{
2450 void *rc;
2451 struct tcp_iter_state *st = seq->private;
2452
2453 st->state = TCP_SEQ_STATE_LISTENING;
2454 rc = listening_get_idx(seq, &pos);
2455
2456 if (!rc) {
2457 st->state = TCP_SEQ_STATE_ESTABLISHED;
2458 rc = established_get_idx(seq, pos);
2459 }
2460
2461 return rc;
2462}
2463
2464static void *tcp_seek_last_pos(struct seq_file *seq)
2465{
2466 struct tcp_iter_state *st = seq->private;
2467 int bucket = st->bucket;
2468 int offset = st->offset;
2469 int orig_num = st->num;
2470 void *rc = NULL;
2471
2472 switch (st->state) {
2473 case TCP_SEQ_STATE_LISTENING:
2474 if (st->bucket >= INET_LHTABLE_SIZE)
2475 break;
2476 st->state = TCP_SEQ_STATE_LISTENING;
2477 rc = listening_get_next(seq, NULL);
2478 while (offset-- && rc && bucket == st->bucket)
2479 rc = listening_get_next(seq, rc);
2480 if (rc)
2481 break;
2482 st->bucket = 0;
2483 st->state = TCP_SEQ_STATE_ESTABLISHED;
2484 fallthrough;
2485 case TCP_SEQ_STATE_ESTABLISHED:
2486 if (st->bucket > tcp_hashinfo.ehash_mask)
2487 break;
2488 rc = established_get_first(seq);
2489 while (offset-- && rc && bucket == st->bucket)
2490 rc = established_get_next(seq, rc);
2491 }
2492
2493 st->num = orig_num;
2494
2495 return rc;
2496}
2497
2498void *tcp_seq_start(struct seq_file *seq, loff_t *pos)
2499{
2500 struct tcp_iter_state *st = seq->private;
2501 void *rc;
2502
2503 if (*pos && *pos == st->last_pos) {
2504 rc = tcp_seek_last_pos(seq);
2505 if (rc)
2506 goto out;
2507 }
2508
2509 st->state = TCP_SEQ_STATE_LISTENING;
2510 st->num = 0;
2511 st->bucket = 0;
2512 st->offset = 0;
2513 rc = *pos ? tcp_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
2514
2515out:
2516 st->last_pos = *pos;
2517 return rc;
2518}
2519EXPORT_SYMBOL(tcp_seq_start);
2520
2521void *tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2522{
2523 struct tcp_iter_state *st = seq->private;
2524 void *rc = NULL;
2525
2526 if (v == SEQ_START_TOKEN) {
2527 rc = tcp_get_idx(seq, 0);
2528 goto out;
2529 }
2530
2531 switch (st->state) {
2532 case TCP_SEQ_STATE_LISTENING:
2533 rc = listening_get_next(seq, v);
2534 if (!rc) {
2535 st->state = TCP_SEQ_STATE_ESTABLISHED;
2536 st->bucket = 0;
2537 st->offset = 0;
2538 rc = established_get_first(seq);
2539 }
2540 break;
2541 case TCP_SEQ_STATE_ESTABLISHED:
2542 rc = established_get_next(seq, v);
2543 break;
2544 }
2545out:
2546 ++*pos;
2547 st->last_pos = *pos;
2548 return rc;
2549}
2550EXPORT_SYMBOL(tcp_seq_next);
2551
2552void tcp_seq_stop(struct seq_file *seq, void *v)
2553{
2554 struct tcp_iter_state *st = seq->private;
2555
2556 switch (st->state) {
2557 case TCP_SEQ_STATE_LISTENING:
2558 if (v != SEQ_START_TOKEN)
2559 spin_unlock(&tcp_hashinfo.listening_hash[st->bucket].lock);
2560 break;
2561 case TCP_SEQ_STATE_ESTABLISHED:
2562 if (v)
2563 spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
2564 break;
2565 }
2566}
2567EXPORT_SYMBOL(tcp_seq_stop);
2568
2569static void get_openreq4(const struct request_sock *req,
2570 struct seq_file *f, int i)
2571{
2572 const struct inet_request_sock *ireq = inet_rsk(req);
2573 long delta = req->rsk_timer.expires - jiffies;
2574
2575 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2576 " %02X %08X:%08X %02X:%08lX %08X %5u %8d %u %d %pK",
2577 i,
2578 ireq->ir_loc_addr,
2579 ireq->ir_num,
2580 ireq->ir_rmt_addr,
2581 ntohs(ireq->ir_rmt_port),
2582 TCP_SYN_RECV,
2583 0, 0, /* could print option size, but that is af dependent. */
2584 1, /* timers active (only the expire timer) */
2585 jiffies_delta_to_clock_t(delta),
2586 req->num_timeout,
2587 from_kuid_munged(seq_user_ns(f),
2588 sock_i_uid(req->rsk_listener)),
2589 0, /* non standard timer */
2590 0, /* open_requests have no inode */
2591 0,
2592 req);
2593}
2594
2595static void get_tcp4_sock(struct sock *sk, struct seq_file *f, int i)
2596{
2597 int timer_active;
2598 unsigned long timer_expires;
2599 const struct tcp_sock *tp = tcp_sk(sk);
2600 const struct inet_connection_sock *icsk = inet_csk(sk);
2601 const struct inet_sock *inet = inet_sk(sk);
2602 const struct fastopen_queue *fastopenq = &icsk->icsk_accept_queue.fastopenq;
2603 __be32 dest = inet->inet_daddr;
2604 __be32 src = inet->inet_rcv_saddr;
2605 __u16 destp = ntohs(inet->inet_dport);
2606 __u16 srcp = ntohs(inet->inet_sport);
2607 int rx_queue;
2608 int state;
2609
2610 if (icsk->icsk_pending == ICSK_TIME_RETRANS ||
2611 icsk->icsk_pending == ICSK_TIME_REO_TIMEOUT ||
2612 icsk->icsk_pending == ICSK_TIME_LOSS_PROBE) {
2613 timer_active = 1;
2614 timer_expires = icsk->icsk_timeout;
2615 } else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
2616 timer_active = 4;
2617 timer_expires = icsk->icsk_timeout;
2618 } else if (timer_pending(&sk->sk_timer)) {
2619 timer_active = 2;
2620 timer_expires = sk->sk_timer.expires;
2621 } else {
2622 timer_active = 0;
2623 timer_expires = jiffies;
2624 }
2625
2626 state = inet_sk_state_load(sk);
2627 if (state == TCP_LISTEN)
2628 rx_queue = READ_ONCE(sk->sk_ack_backlog);
2629 else
2630 /* Because we don't lock the socket,
2631 * we might find a transient negative value.
2632 */
2633 rx_queue = max_t(int, READ_ONCE(tp->rcv_nxt) -
2634 READ_ONCE(tp->copied_seq), 0);
2635
2636 seq_printf(f, "%4d: %08X:%04X %08X:%04X %02X %08X:%08X %02X:%08lX "
2637 "%08X %5u %8d %lu %d %pK %lu %lu %u %u %d",
2638 i, src, srcp, dest, destp, state,
2639 READ_ONCE(tp->write_seq) - tp->snd_una,
2640 rx_queue,
2641 timer_active,
2642 jiffies_delta_to_clock_t(timer_expires - jiffies),
2643 icsk->icsk_retransmits,
2644 from_kuid_munged(seq_user_ns(f), sock_i_uid(sk)),
2645 icsk->icsk_probes_out,
2646 sock_i_ino(sk),
2647 refcount_read(&sk->sk_refcnt), sk,
2648 jiffies_to_clock_t(icsk->icsk_rto),
2649 jiffies_to_clock_t(icsk->icsk_ack.ato),
2650 (icsk->icsk_ack.quick << 1) | inet_csk_in_pingpong_mode(sk),
2651 tp->snd_cwnd,
2652 state == TCP_LISTEN ?
2653 fastopenq->max_qlen :
2654 (tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh));
2655}
2656
2657static void get_timewait4_sock(const struct inet_timewait_sock *tw,
2658 struct seq_file *f, int i)
2659{
2660 long delta = tw->tw_timer.expires - jiffies;
2661 __be32 dest, src;
2662 __u16 destp, srcp;
2663
2664 dest = tw->tw_daddr;
2665 src = tw->tw_rcv_saddr;
2666 destp = ntohs(tw->tw_dport);
2667 srcp = ntohs(tw->tw_sport);
2668
2669 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2670 " %02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK",
2671 i, src, srcp, dest, destp, tw->tw_substate, 0, 0,
2672 3, jiffies_delta_to_clock_t(delta), 0, 0, 0, 0,
2673 refcount_read(&tw->tw_refcnt), tw);
2674}
2675
2676#define TMPSZ 150
2677
2678static int tcp4_seq_show(struct seq_file *seq, void *v)
2679{
2680 struct tcp_iter_state *st;
2681 struct sock *sk = v;
2682
2683 seq_setwidth(seq, TMPSZ - 1);
2684 if (v == SEQ_START_TOKEN) {
2685 seq_puts(seq, " sl local_address rem_address st tx_queue "
2686 "rx_queue tr tm->when retrnsmt uid timeout "
2687 "inode");
2688 goto out;
2689 }
2690 st = seq->private;
2691
2692 if (sk->sk_state == TCP_TIME_WAIT)
2693 get_timewait4_sock(v, seq, st->num);
2694 else if (sk->sk_state == TCP_NEW_SYN_RECV)
2695 get_openreq4(v, seq, st->num);
2696 else
2697 get_tcp4_sock(v, seq, st->num);
2698out:
2699 seq_pad(seq, '\n');
2700 return 0;
2701}
2702
2703#ifdef CONFIG_BPF_SYSCALL
2704struct bpf_iter__tcp {
2705 __bpf_md_ptr(struct bpf_iter_meta *, meta);
2706 __bpf_md_ptr(struct sock_common *, sk_common);
2707 uid_t uid __aligned(8);
2708};
2709
2710static int tcp_prog_seq_show(struct bpf_prog *prog, struct bpf_iter_meta *meta,
2711 struct sock_common *sk_common, uid_t uid)
2712{
2713 struct bpf_iter__tcp ctx;
2714
2715 meta->seq_num--; /* skip SEQ_START_TOKEN */
2716 ctx.meta = meta;
2717 ctx.sk_common = sk_common;
2718 ctx.uid = uid;
2719 return bpf_iter_run_prog(prog, &ctx);
2720}
2721
2722static int bpf_iter_tcp_seq_show(struct seq_file *seq, void *v)
2723{
2724 struct bpf_iter_meta meta;
2725 struct bpf_prog *prog;
2726 struct sock *sk = v;
2727 uid_t uid;
2728
2729 if (v == SEQ_START_TOKEN)
2730 return 0;
2731
2732 if (sk->sk_state == TCP_TIME_WAIT) {
2733 uid = 0;
2734 } else if (sk->sk_state == TCP_NEW_SYN_RECV) {
2735 const struct request_sock *req = v;
2736
2737 uid = from_kuid_munged(seq_user_ns(seq),
2738 sock_i_uid(req->rsk_listener));
2739 } else {
2740 uid = from_kuid_munged(seq_user_ns(seq), sock_i_uid(sk));
2741 }
2742
2743 meta.seq = seq;
2744 prog = bpf_iter_get_info(&meta, false);
2745 return tcp_prog_seq_show(prog, &meta, v, uid);
2746}
2747
2748static void bpf_iter_tcp_seq_stop(struct seq_file *seq, void *v)
2749{
2750 struct bpf_iter_meta meta;
2751 struct bpf_prog *prog;
2752
2753 if (!v) {
2754 meta.seq = seq;
2755 prog = bpf_iter_get_info(&meta, true);
2756 if (prog)
2757 (void)tcp_prog_seq_show(prog, &meta, v, 0);
2758 }
2759
2760 tcp_seq_stop(seq, v);
2761}
2762
2763static const struct seq_operations bpf_iter_tcp_seq_ops = {
2764 .show = bpf_iter_tcp_seq_show,
2765 .start = tcp_seq_start,
2766 .next = tcp_seq_next,
2767 .stop = bpf_iter_tcp_seq_stop,
2768};
2769#endif
2770
2771static const struct seq_operations tcp4_seq_ops = {
2772 .show = tcp4_seq_show,
2773 .start = tcp_seq_start,
2774 .next = tcp_seq_next,
2775 .stop = tcp_seq_stop,
2776};
2777
2778static struct tcp_seq_afinfo tcp4_seq_afinfo = {
2779 .family = AF_INET,
2780};
2781
2782static int __net_init tcp4_proc_init_net(struct net *net)
2783{
2784 if (!proc_create_net_data("tcp", 0444, net->proc_net, &tcp4_seq_ops,
2785 sizeof(struct tcp_iter_state), &tcp4_seq_afinfo))
2786 return -ENOMEM;
2787 return 0;
2788}
2789
2790static void __net_exit tcp4_proc_exit_net(struct net *net)
2791{
2792 remove_proc_entry("tcp", net->proc_net);
2793}
2794
2795static struct pernet_operations tcp4_net_ops = {
2796 .init = tcp4_proc_init_net,
2797 .exit = tcp4_proc_exit_net,
2798};
2799
2800int __init tcp4_proc_init(void)
2801{
2802 return register_pernet_subsys(&tcp4_net_ops);
2803}
2804
2805void tcp4_proc_exit(void)
2806{
2807 unregister_pernet_subsys(&tcp4_net_ops);
2808}
2809#endif /* CONFIG_PROC_FS */
2810
2811/* @wake is one when sk_stream_write_space() calls us.
2812 * This sends EPOLLOUT only if notsent_bytes is half the limit.
2813 * This mimics the strategy used in sock_def_write_space().
2814 */
2815bool tcp_stream_memory_free(const struct sock *sk, int wake)
2816{
2817 const struct tcp_sock *tp = tcp_sk(sk);
2818 u32 notsent_bytes = READ_ONCE(tp->write_seq) -
2819 READ_ONCE(tp->snd_nxt);
2820
2821 return (notsent_bytes << wake) < tcp_notsent_lowat(tp);
2822}
2823EXPORT_SYMBOL(tcp_stream_memory_free);
2824
2825struct proto tcp_prot = {
2826 .name = "TCP",
2827 .owner = THIS_MODULE,
2828 .close = tcp_close,
2829 .pre_connect = tcp_v4_pre_connect,
2830 .connect = tcp_v4_connect,
2831 .disconnect = tcp_disconnect,
2832 .accept = inet_csk_accept,
2833 .ioctl = tcp_ioctl,
2834 .init = tcp_v4_init_sock,
2835 .destroy = tcp_v4_destroy_sock,
2836 .shutdown = tcp_shutdown,
2837 .setsockopt = tcp_setsockopt,
2838 .getsockopt = tcp_getsockopt,
2839 .bpf_bypass_getsockopt = tcp_bpf_bypass_getsockopt,
2840 .keepalive = tcp_set_keepalive,
2841 .recvmsg = tcp_recvmsg,
2842 .sendmsg = tcp_sendmsg,
2843 .sendpage = tcp_sendpage,
2844 .backlog_rcv = tcp_v4_do_rcv,
2845 .release_cb = tcp_release_cb,
2846 .hash = inet_hash,
2847 .unhash = inet_unhash,
2848 .get_port = inet_csk_get_port,
2849#ifdef CONFIG_BPF_SYSCALL
2850 .psock_update_sk_prot = tcp_bpf_update_proto,
2851#endif
2852 .enter_memory_pressure = tcp_enter_memory_pressure,
2853 .leave_memory_pressure = tcp_leave_memory_pressure,
2854 .stream_memory_free = tcp_stream_memory_free,
2855 .sockets_allocated = &tcp_sockets_allocated,
2856 .orphan_count = &tcp_orphan_count,
2857 .memory_allocated = &tcp_memory_allocated,
2858 .memory_pressure = &tcp_memory_pressure,
2859 .sysctl_mem = sysctl_tcp_mem,
2860 .sysctl_wmem_offset = offsetof(struct net, ipv4.sysctl_tcp_wmem),
2861 .sysctl_rmem_offset = offsetof(struct net, ipv4.sysctl_tcp_rmem),
2862 .max_header = MAX_TCP_HEADER,
2863 .obj_size = sizeof(struct tcp_sock),
2864 .slab_flags = SLAB_TYPESAFE_BY_RCU,
2865 .twsk_prot = &tcp_timewait_sock_ops,
2866 .rsk_prot = &tcp_request_sock_ops,
2867 .h.hashinfo = &tcp_hashinfo,
2868 .no_autobind = true,
2869 .diag_destroy = tcp_abort,
2870};
2871EXPORT_SYMBOL(tcp_prot);
2872
2873static void __net_exit tcp_sk_exit(struct net *net)
2874{
2875 int cpu;
2876
2877 if (net->ipv4.tcp_congestion_control)
2878 bpf_module_put(net->ipv4.tcp_congestion_control,
2879 net->ipv4.tcp_congestion_control->owner);
2880
2881 for_each_possible_cpu(cpu)
2882 inet_ctl_sock_destroy(*per_cpu_ptr(net->ipv4.tcp_sk, cpu));
2883 free_percpu(net->ipv4.tcp_sk);
2884}
2885
2886static int __net_init tcp_sk_init(struct net *net)
2887{
2888 int res, cpu, cnt;
2889
2890 net->ipv4.tcp_sk = alloc_percpu(struct sock *);
2891 if (!net->ipv4.tcp_sk)
2892 return -ENOMEM;
2893
2894 for_each_possible_cpu(cpu) {
2895 struct sock *sk;
2896
2897 res = inet_ctl_sock_create(&sk, PF_INET, SOCK_RAW,
2898 IPPROTO_TCP, net);
2899 if (res)
2900 goto fail;
2901 sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
2902
2903 /* Please enforce IP_DF and IPID==0 for RST and
2904 * ACK sent in SYN-RECV and TIME-WAIT state.
2905 */
2906 inet_sk(sk)->pmtudisc = IP_PMTUDISC_DO;
2907
2908 *per_cpu_ptr(net->ipv4.tcp_sk, cpu) = sk;
2909 }
2910
2911 net->ipv4.sysctl_tcp_ecn = 2;
2912 net->ipv4.sysctl_tcp_ecn_fallback = 1;
2913
2914 net->ipv4.sysctl_tcp_base_mss = TCP_BASE_MSS;
2915 net->ipv4.sysctl_tcp_min_snd_mss = TCP_MIN_SND_MSS;
2916 net->ipv4.sysctl_tcp_probe_threshold = TCP_PROBE_THRESHOLD;
2917 net->ipv4.sysctl_tcp_probe_interval = TCP_PROBE_INTERVAL;
2918 net->ipv4.sysctl_tcp_mtu_probe_floor = TCP_MIN_SND_MSS;
2919
2920 net->ipv4.sysctl_tcp_keepalive_time = TCP_KEEPALIVE_TIME;
2921 net->ipv4.sysctl_tcp_keepalive_probes = TCP_KEEPALIVE_PROBES;
2922 net->ipv4.sysctl_tcp_keepalive_intvl = TCP_KEEPALIVE_INTVL;
2923
2924 net->ipv4.sysctl_tcp_syn_retries = TCP_SYN_RETRIES;
2925 net->ipv4.sysctl_tcp_synack_retries = TCP_SYNACK_RETRIES;
2926 net->ipv4.sysctl_tcp_syncookies = 1;
2927 net->ipv4.sysctl_tcp_reordering = TCP_FASTRETRANS_THRESH;
2928 net->ipv4.sysctl_tcp_retries1 = TCP_RETR1;
2929 net->ipv4.sysctl_tcp_retries2 = TCP_RETR2;
2930 net->ipv4.sysctl_tcp_orphan_retries = 0;
2931 net->ipv4.sysctl_tcp_fin_timeout = TCP_FIN_TIMEOUT;
2932 net->ipv4.sysctl_tcp_notsent_lowat = UINT_MAX;
2933 net->ipv4.sysctl_tcp_tw_reuse = 2;
2934 net->ipv4.sysctl_tcp_no_ssthresh_metrics_save = 1;
2935
2936 cnt = tcp_hashinfo.ehash_mask + 1;
2937 net->ipv4.tcp_death_row.sysctl_max_tw_buckets = cnt / 2;
2938 net->ipv4.tcp_death_row.hashinfo = &tcp_hashinfo;
2939
2940 net->ipv4.sysctl_max_syn_backlog = max(128, cnt / 128);
2941 net->ipv4.sysctl_tcp_sack = 1;
2942 net->ipv4.sysctl_tcp_window_scaling = 1;
2943 net->ipv4.sysctl_tcp_timestamps = 1;
2944 net->ipv4.sysctl_tcp_early_retrans = 3;
2945 net->ipv4.sysctl_tcp_recovery = TCP_RACK_LOSS_DETECTION;
2946 net->ipv4.sysctl_tcp_slow_start_after_idle = 1; /* By default, RFC2861 behavior. */
2947 net->ipv4.sysctl_tcp_retrans_collapse = 1;
2948 net->ipv4.sysctl_tcp_max_reordering = 300;
2949 net->ipv4.sysctl_tcp_dsack = 1;
2950 net->ipv4.sysctl_tcp_app_win = 31;
2951 net->ipv4.sysctl_tcp_adv_win_scale = 1;
2952 net->ipv4.sysctl_tcp_frto = 2;
2953 net->ipv4.sysctl_tcp_moderate_rcvbuf = 1;
2954 /* This limits the percentage of the congestion window which we
2955 * will allow a single TSO frame to consume. Building TSO frames
2956 * which are too large can cause TCP streams to be bursty.
2957 */
2958 net->ipv4.sysctl_tcp_tso_win_divisor = 3;
2959 /* Default TSQ limit of 16 TSO segments */
2960 net->ipv4.sysctl_tcp_limit_output_bytes = 16 * 65536;
2961 /* rfc5961 challenge ack rate limiting */
2962 net->ipv4.sysctl_tcp_challenge_ack_limit = 1000;
2963 net->ipv4.sysctl_tcp_min_tso_segs = 2;
2964 net->ipv4.sysctl_tcp_min_rtt_wlen = 300;
2965 net->ipv4.sysctl_tcp_autocorking = 1;
2966 net->ipv4.sysctl_tcp_invalid_ratelimit = HZ/2;
2967 net->ipv4.sysctl_tcp_pacing_ss_ratio = 200;
2968 net->ipv4.sysctl_tcp_pacing_ca_ratio = 120;
2969 if (net != &init_net) {
2970 memcpy(net->ipv4.sysctl_tcp_rmem,
2971 init_net.ipv4.sysctl_tcp_rmem,
2972 sizeof(init_net.ipv4.sysctl_tcp_rmem));
2973 memcpy(net->ipv4.sysctl_tcp_wmem,
2974 init_net.ipv4.sysctl_tcp_wmem,
2975 sizeof(init_net.ipv4.sysctl_tcp_wmem));
2976 }
2977 net->ipv4.sysctl_tcp_comp_sack_delay_ns = NSEC_PER_MSEC;
2978 net->ipv4.sysctl_tcp_comp_sack_slack_ns = 100 * NSEC_PER_USEC;
2979 net->ipv4.sysctl_tcp_comp_sack_nr = 44;
2980 net->ipv4.sysctl_tcp_fastopen = TFO_CLIENT_ENABLE;
2981 spin_lock_init(&net->ipv4.tcp_fastopen_ctx_lock);
2982 net->ipv4.sysctl_tcp_fastopen_blackhole_timeout = 0;
2983 atomic_set(&net->ipv4.tfo_active_disable_times, 0);
2984
2985 /* Reno is always built in */
2986 if (!net_eq(net, &init_net) &&
2987 bpf_try_module_get(init_net.ipv4.tcp_congestion_control,
2988 init_net.ipv4.tcp_congestion_control->owner))
2989 net->ipv4.tcp_congestion_control = init_net.ipv4.tcp_congestion_control;
2990 else
2991 net->ipv4.tcp_congestion_control = &tcp_reno;
2992
2993 return 0;
2994fail:
2995 tcp_sk_exit(net);
2996
2997 return res;
2998}
2999
3000static void __net_exit tcp_sk_exit_batch(struct list_head *net_exit_list)
3001{
3002 struct net *net;
3003
3004 inet_twsk_purge(&tcp_hashinfo, AF_INET);
3005
3006 list_for_each_entry(net, net_exit_list, exit_list)
3007 tcp_fastopen_ctx_destroy(net);
3008}
3009
3010static struct pernet_operations __net_initdata tcp_sk_ops = {
3011 .init = tcp_sk_init,
3012 .exit = tcp_sk_exit,
3013 .exit_batch = tcp_sk_exit_batch,
3014};
3015
3016#if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS)
3017DEFINE_BPF_ITER_FUNC(tcp, struct bpf_iter_meta *meta,
3018 struct sock_common *sk_common, uid_t uid)
3019
3020static int bpf_iter_init_tcp(void *priv_data, struct bpf_iter_aux_info *aux)
3021{
3022 struct tcp_iter_state *st = priv_data;
3023 struct tcp_seq_afinfo *afinfo;
3024 int ret;
3025
3026 afinfo = kmalloc(sizeof(*afinfo), GFP_USER | __GFP_NOWARN);
3027 if (!afinfo)
3028 return -ENOMEM;
3029
3030 afinfo->family = AF_UNSPEC;
3031 st->bpf_seq_afinfo = afinfo;
3032 ret = bpf_iter_init_seq_net(priv_data, aux);
3033 if (ret)
3034 kfree(afinfo);
3035 return ret;
3036}
3037
3038static void bpf_iter_fini_tcp(void *priv_data)
3039{
3040 struct tcp_iter_state *st = priv_data;
3041
3042 kfree(st->bpf_seq_afinfo);
3043 bpf_iter_fini_seq_net(priv_data);
3044}
3045
3046static const struct bpf_iter_seq_info tcp_seq_info = {
3047 .seq_ops = &bpf_iter_tcp_seq_ops,
3048 .init_seq_private = bpf_iter_init_tcp,
3049 .fini_seq_private = bpf_iter_fini_tcp,
3050 .seq_priv_size = sizeof(struct tcp_iter_state),
3051};
3052
3053static struct bpf_iter_reg tcp_reg_info = {
3054 .target = "tcp",
3055 .ctx_arg_info_size = 1,
3056 .ctx_arg_info = {
3057 { offsetof(struct bpf_iter__tcp, sk_common),
3058 PTR_TO_BTF_ID_OR_NULL },
3059 },
3060 .seq_info = &tcp_seq_info,
3061};
3062
3063static void __init bpf_iter_register(void)
3064{
3065 tcp_reg_info.ctx_arg_info[0].btf_id = btf_sock_ids[BTF_SOCK_TYPE_SOCK_COMMON];
3066 if (bpf_iter_reg_target(&tcp_reg_info))
3067 pr_warn("Warning: could not register bpf iterator tcp\n");
3068}
3069
3070#endif
3071
3072void __init tcp_v4_init(void)
3073{
3074 if (register_pernet_subsys(&tcp_sk_ops))
3075 panic("Failed to create the TCP control socket.\n");
3076
3077#if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS)
3078 bpf_iter_register();
3079#endif
3080}
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * INET An implementation of the TCP/IP protocol suite for the LINUX
4 * operating system. INET is implemented using the BSD Socket
5 * interface as the means of communication with the user level.
6 *
7 * Implementation of the Transmission Control Protocol(TCP).
8 *
9 * IPv4 specific functions
10 *
11 * code split from:
12 * linux/ipv4/tcp.c
13 * linux/ipv4/tcp_input.c
14 * linux/ipv4/tcp_output.c
15 *
16 * See tcp.c for author information
17 */
18
19/*
20 * Changes:
21 * David S. Miller : New socket lookup architecture.
22 * This code is dedicated to John Dyson.
23 * David S. Miller : Change semantics of established hash,
24 * half is devoted to TIME_WAIT sockets
25 * and the rest go in the other half.
26 * Andi Kleen : Add support for syncookies and fixed
27 * some bugs: ip options weren't passed to
28 * the TCP layer, missed a check for an
29 * ACK bit.
30 * Andi Kleen : Implemented fast path mtu discovery.
31 * Fixed many serious bugs in the
32 * request_sock handling and moved
33 * most of it into the af independent code.
34 * Added tail drop and some other bugfixes.
35 * Added new listen semantics.
36 * Mike McLagan : Routing by source
37 * Juan Jose Ciarlante: ip_dynaddr bits
38 * Andi Kleen: various fixes.
39 * Vitaly E. Lavrov : Transparent proxy revived after year
40 * coma.
41 * Andi Kleen : Fix new listen.
42 * Andi Kleen : Fix accept error reporting.
43 * YOSHIFUJI Hideaki @USAGI and: Support IPV6_V6ONLY socket option, which
44 * Alexey Kuznetsov allow both IPv4 and IPv6 sockets to bind
45 * a single port at the same time.
46 */
47
48#define pr_fmt(fmt) "TCP: " fmt
49
50#include <linux/bottom_half.h>
51#include <linux/types.h>
52#include <linux/fcntl.h>
53#include <linux/module.h>
54#include <linux/random.h>
55#include <linux/cache.h>
56#include <linux/jhash.h>
57#include <linux/init.h>
58#include <linux/times.h>
59#include <linux/slab.h>
60#include <linux/sched.h>
61
62#include <net/net_namespace.h>
63#include <net/icmp.h>
64#include <net/inet_hashtables.h>
65#include <net/tcp.h>
66#include <net/transp_v6.h>
67#include <net/ipv6.h>
68#include <net/inet_common.h>
69#include <net/timewait_sock.h>
70#include <net/xfrm.h>
71#include <net/secure_seq.h>
72#include <net/busy_poll.h>
73#include <net/rstreason.h>
74
75#include <linux/inet.h>
76#include <linux/ipv6.h>
77#include <linux/stddef.h>
78#include <linux/proc_fs.h>
79#include <linux/seq_file.h>
80#include <linux/inetdevice.h>
81#include <linux/btf_ids.h>
82#include <linux/skbuff_ref.h>
83
84#include <crypto/hash.h>
85#include <linux/scatterlist.h>
86
87#include <trace/events/tcp.h>
88
89#ifdef CONFIG_TCP_MD5SIG
90static int tcp_v4_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key,
91 __be32 daddr, __be32 saddr, const struct tcphdr *th);
92#endif
93
94struct inet_hashinfo tcp_hashinfo;
95EXPORT_SYMBOL(tcp_hashinfo);
96
97static DEFINE_PER_CPU(struct sock_bh_locked, ipv4_tcp_sk) = {
98 .bh_lock = INIT_LOCAL_LOCK(bh_lock),
99};
100
101static DEFINE_MUTEX(tcp_exit_batch_mutex);
102
103static u32 tcp_v4_init_seq(const struct sk_buff *skb)
104{
105 return secure_tcp_seq(ip_hdr(skb)->daddr,
106 ip_hdr(skb)->saddr,
107 tcp_hdr(skb)->dest,
108 tcp_hdr(skb)->source);
109}
110
111static u32 tcp_v4_init_ts_off(const struct net *net, const struct sk_buff *skb)
112{
113 return secure_tcp_ts_off(net, ip_hdr(skb)->daddr, ip_hdr(skb)->saddr);
114}
115
116int tcp_twsk_unique(struct sock *sk, struct sock *sktw, void *twp)
117{
118 int reuse = READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_tw_reuse);
119 const struct inet_timewait_sock *tw = inet_twsk(sktw);
120 const struct tcp_timewait_sock *tcptw = tcp_twsk(sktw);
121 struct tcp_sock *tp = tcp_sk(sk);
122 int ts_recent_stamp;
123
124 if (READ_ONCE(tw->tw_substate) == TCP_FIN_WAIT2)
125 reuse = 0;
126
127 if (reuse == 2) {
128 /* Still does not detect *everything* that goes through
129 * lo, since we require a loopback src or dst address
130 * or direct binding to 'lo' interface.
131 */
132 bool loopback = false;
133 if (tw->tw_bound_dev_if == LOOPBACK_IFINDEX)
134 loopback = true;
135#if IS_ENABLED(CONFIG_IPV6)
136 if (tw->tw_family == AF_INET6) {
137 if (ipv6_addr_loopback(&tw->tw_v6_daddr) ||
138 ipv6_addr_v4mapped_loopback(&tw->tw_v6_daddr) ||
139 ipv6_addr_loopback(&tw->tw_v6_rcv_saddr) ||
140 ipv6_addr_v4mapped_loopback(&tw->tw_v6_rcv_saddr))
141 loopback = true;
142 } else
143#endif
144 {
145 if (ipv4_is_loopback(tw->tw_daddr) ||
146 ipv4_is_loopback(tw->tw_rcv_saddr))
147 loopback = true;
148 }
149 if (!loopback)
150 reuse = 0;
151 }
152
153 /* With PAWS, it is safe from the viewpoint
154 of data integrity. Even without PAWS it is safe provided sequence
155 spaces do not overlap i.e. at data rates <= 80Mbit/sec.
156
157 Actually, the idea is close to VJ's one, only timestamp cache is
158 held not per host, but per port pair and TW bucket is used as state
159 holder.
160
161 If TW bucket has been already destroyed we fall back to VJ's scheme
162 and use initial timestamp retrieved from peer table.
163 */
164 ts_recent_stamp = READ_ONCE(tcptw->tw_ts_recent_stamp);
165 if (ts_recent_stamp &&
166 (!twp || (reuse && time_after32(ktime_get_seconds(),
167 ts_recent_stamp)))) {
168 /* inet_twsk_hashdance_schedule() sets sk_refcnt after putting twsk
169 * and releasing the bucket lock.
170 */
171 if (unlikely(!refcount_inc_not_zero(&sktw->sk_refcnt)))
172 return 0;
173
174 /* In case of repair and re-using TIME-WAIT sockets we still
175 * want to be sure that it is safe as above but honor the
176 * sequence numbers and time stamps set as part of the repair
177 * process.
178 *
179 * Without this check re-using a TIME-WAIT socket with TCP
180 * repair would accumulate a -1 on the repair assigned
181 * sequence number. The first time it is reused the sequence
182 * is -1, the second time -2, etc. This fixes that issue
183 * without appearing to create any others.
184 */
185 if (likely(!tp->repair)) {
186 u32 seq = tcptw->tw_snd_nxt + 65535 + 2;
187
188 if (!seq)
189 seq = 1;
190 WRITE_ONCE(tp->write_seq, seq);
191 tp->rx_opt.ts_recent = READ_ONCE(tcptw->tw_ts_recent);
192 tp->rx_opt.ts_recent_stamp = ts_recent_stamp;
193 }
194
195 return 1;
196 }
197
198 return 0;
199}
200EXPORT_SYMBOL_GPL(tcp_twsk_unique);
201
202static int tcp_v4_pre_connect(struct sock *sk, struct sockaddr *uaddr,
203 int addr_len)
204{
205 /* This check is replicated from tcp_v4_connect() and intended to
206 * prevent BPF program called below from accessing bytes that are out
207 * of the bound specified by user in addr_len.
208 */
209 if (addr_len < sizeof(struct sockaddr_in))
210 return -EINVAL;
211
212 sock_owned_by_me(sk);
213
214 return BPF_CGROUP_RUN_PROG_INET4_CONNECT(sk, uaddr, &addr_len);
215}
216
217/* This will initiate an outgoing connection. */
218int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
219{
220 struct sockaddr_in *usin = (struct sockaddr_in *)uaddr;
221 struct inet_timewait_death_row *tcp_death_row;
222 struct inet_sock *inet = inet_sk(sk);
223 struct tcp_sock *tp = tcp_sk(sk);
224 struct ip_options_rcu *inet_opt;
225 struct net *net = sock_net(sk);
226 __be16 orig_sport, orig_dport;
227 __be32 daddr, nexthop;
228 struct flowi4 *fl4;
229 struct rtable *rt;
230 int err;
231
232 if (addr_len < sizeof(struct sockaddr_in))
233 return -EINVAL;
234
235 if (usin->sin_family != AF_INET)
236 return -EAFNOSUPPORT;
237
238 nexthop = daddr = usin->sin_addr.s_addr;
239 inet_opt = rcu_dereference_protected(inet->inet_opt,
240 lockdep_sock_is_held(sk));
241 if (inet_opt && inet_opt->opt.srr) {
242 if (!daddr)
243 return -EINVAL;
244 nexthop = inet_opt->opt.faddr;
245 }
246
247 orig_sport = inet->inet_sport;
248 orig_dport = usin->sin_port;
249 fl4 = &inet->cork.fl.u.ip4;
250 rt = ip_route_connect(fl4, nexthop, inet->inet_saddr,
251 sk->sk_bound_dev_if, IPPROTO_TCP, orig_sport,
252 orig_dport, sk);
253 if (IS_ERR(rt)) {
254 err = PTR_ERR(rt);
255 if (err == -ENETUNREACH)
256 IP_INC_STATS(net, IPSTATS_MIB_OUTNOROUTES);
257 return err;
258 }
259
260 if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) {
261 ip_rt_put(rt);
262 return -ENETUNREACH;
263 }
264
265 if (!inet_opt || !inet_opt->opt.srr)
266 daddr = fl4->daddr;
267
268 tcp_death_row = &sock_net(sk)->ipv4.tcp_death_row;
269
270 if (!inet->inet_saddr) {
271 err = inet_bhash2_update_saddr(sk, &fl4->saddr, AF_INET);
272 if (err) {
273 ip_rt_put(rt);
274 return err;
275 }
276 } else {
277 sk_rcv_saddr_set(sk, inet->inet_saddr);
278 }
279
280 if (tp->rx_opt.ts_recent_stamp && inet->inet_daddr != daddr) {
281 /* Reset inherited state */
282 tp->rx_opt.ts_recent = 0;
283 tp->rx_opt.ts_recent_stamp = 0;
284 if (likely(!tp->repair))
285 WRITE_ONCE(tp->write_seq, 0);
286 }
287
288 inet->inet_dport = usin->sin_port;
289 sk_daddr_set(sk, daddr);
290
291 inet_csk(sk)->icsk_ext_hdr_len = 0;
292 if (inet_opt)
293 inet_csk(sk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
294
295 tp->rx_opt.mss_clamp = TCP_MSS_DEFAULT;
296
297 /* Socket identity is still unknown (sport may be zero).
298 * However we set state to SYN-SENT and not releasing socket
299 * lock select source port, enter ourselves into the hash tables and
300 * complete initialization after this.
301 */
302 tcp_set_state(sk, TCP_SYN_SENT);
303 err = inet_hash_connect(tcp_death_row, sk);
304 if (err)
305 goto failure;
306
307 sk_set_txhash(sk);
308
309 rt = ip_route_newports(fl4, rt, orig_sport, orig_dport,
310 inet->inet_sport, inet->inet_dport, sk);
311 if (IS_ERR(rt)) {
312 err = PTR_ERR(rt);
313 rt = NULL;
314 goto failure;
315 }
316 tp->tcp_usec_ts = dst_tcp_usec_ts(&rt->dst);
317 /* OK, now commit destination to socket. */
318 sk->sk_gso_type = SKB_GSO_TCPV4;
319 sk_setup_caps(sk, &rt->dst);
320 rt = NULL;
321
322 if (likely(!tp->repair)) {
323 if (!tp->write_seq)
324 WRITE_ONCE(tp->write_seq,
325 secure_tcp_seq(inet->inet_saddr,
326 inet->inet_daddr,
327 inet->inet_sport,
328 usin->sin_port));
329 WRITE_ONCE(tp->tsoffset,
330 secure_tcp_ts_off(net, inet->inet_saddr,
331 inet->inet_daddr));
332 }
333
334 atomic_set(&inet->inet_id, get_random_u16());
335
336 if (tcp_fastopen_defer_connect(sk, &err))
337 return err;
338 if (err)
339 goto failure;
340
341 err = tcp_connect(sk);
342
343 if (err)
344 goto failure;
345
346 return 0;
347
348failure:
349 /*
350 * This unhashes the socket and releases the local port,
351 * if necessary.
352 */
353 tcp_set_state(sk, TCP_CLOSE);
354 inet_bhash2_reset_saddr(sk);
355 ip_rt_put(rt);
356 sk->sk_route_caps = 0;
357 inet->inet_dport = 0;
358 return err;
359}
360EXPORT_SYMBOL(tcp_v4_connect);
361
362/*
363 * This routine reacts to ICMP_FRAG_NEEDED mtu indications as defined in RFC1191.
364 * It can be called through tcp_release_cb() if socket was owned by user
365 * at the time tcp_v4_err() was called to handle ICMP message.
366 */
367void tcp_v4_mtu_reduced(struct sock *sk)
368{
369 struct inet_sock *inet = inet_sk(sk);
370 struct dst_entry *dst;
371 u32 mtu;
372
373 if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE))
374 return;
375 mtu = READ_ONCE(tcp_sk(sk)->mtu_info);
376 dst = inet_csk_update_pmtu(sk, mtu);
377 if (!dst)
378 return;
379
380 /* Something is about to be wrong... Remember soft error
381 * for the case, if this connection will not able to recover.
382 */
383 if (mtu < dst_mtu(dst) && ip_dont_fragment(sk, dst))
384 WRITE_ONCE(sk->sk_err_soft, EMSGSIZE);
385
386 mtu = dst_mtu(dst);
387
388 if (inet->pmtudisc != IP_PMTUDISC_DONT &&
389 ip_sk_accept_pmtu(sk) &&
390 inet_csk(sk)->icsk_pmtu_cookie > mtu) {
391 tcp_sync_mss(sk, mtu);
392
393 /* Resend the TCP packet because it's
394 * clear that the old packet has been
395 * dropped. This is the new "fast" path mtu
396 * discovery.
397 */
398 tcp_simple_retransmit(sk);
399 } /* else let the usual retransmit timer handle it */
400}
401EXPORT_SYMBOL(tcp_v4_mtu_reduced);
402
403static void do_redirect(struct sk_buff *skb, struct sock *sk)
404{
405 struct dst_entry *dst = __sk_dst_check(sk, 0);
406
407 if (dst)
408 dst->ops->redirect(dst, sk, skb);
409}
410
411
412/* handle ICMP messages on TCP_NEW_SYN_RECV request sockets */
413void tcp_req_err(struct sock *sk, u32 seq, bool abort)
414{
415 struct request_sock *req = inet_reqsk(sk);
416 struct net *net = sock_net(sk);
417
418 /* ICMPs are not backlogged, hence we cannot get
419 * an established socket here.
420 */
421 if (seq != tcp_rsk(req)->snt_isn) {
422 __NET_INC_STATS(net, LINUX_MIB_OUTOFWINDOWICMPS);
423 } else if (abort) {
424 /*
425 * Still in SYN_RECV, just remove it silently.
426 * There is no good way to pass the error to the newly
427 * created socket, and POSIX does not want network
428 * errors returned from accept().
429 */
430 inet_csk_reqsk_queue_drop(req->rsk_listener, req);
431 tcp_listendrop(req->rsk_listener);
432 }
433 reqsk_put(req);
434}
435EXPORT_SYMBOL(tcp_req_err);
436
437/* TCP-LD (RFC 6069) logic */
438void tcp_ld_RTO_revert(struct sock *sk, u32 seq)
439{
440 struct inet_connection_sock *icsk = inet_csk(sk);
441 struct tcp_sock *tp = tcp_sk(sk);
442 struct sk_buff *skb;
443 s32 remaining;
444 u32 delta_us;
445
446 if (sock_owned_by_user(sk))
447 return;
448
449 if (seq != tp->snd_una || !icsk->icsk_retransmits ||
450 !icsk->icsk_backoff)
451 return;
452
453 skb = tcp_rtx_queue_head(sk);
454 if (WARN_ON_ONCE(!skb))
455 return;
456
457 icsk->icsk_backoff--;
458 icsk->icsk_rto = tp->srtt_us ? __tcp_set_rto(tp) : TCP_TIMEOUT_INIT;
459 icsk->icsk_rto = inet_csk_rto_backoff(icsk, TCP_RTO_MAX);
460
461 tcp_mstamp_refresh(tp);
462 delta_us = (u32)(tp->tcp_mstamp - tcp_skb_timestamp_us(skb));
463 remaining = icsk->icsk_rto - usecs_to_jiffies(delta_us);
464
465 if (remaining > 0) {
466 inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
467 remaining, TCP_RTO_MAX);
468 } else {
469 /* RTO revert clocked out retransmission.
470 * Will retransmit now.
471 */
472 tcp_retransmit_timer(sk);
473 }
474}
475EXPORT_SYMBOL(tcp_ld_RTO_revert);
476
477/*
478 * This routine is called by the ICMP module when it gets some
479 * sort of error condition. If err < 0 then the socket should
480 * be closed and the error returned to the user. If err > 0
481 * it's just the icmp type << 8 | icmp code. After adjustment
482 * header points to the first 8 bytes of the tcp header. We need
483 * to find the appropriate port.
484 *
485 * The locking strategy used here is very "optimistic". When
486 * someone else accesses the socket the ICMP is just dropped
487 * and for some paths there is no check at all.
488 * A more general error queue to queue errors for later handling
489 * is probably better.
490 *
491 */
492
493int tcp_v4_err(struct sk_buff *skb, u32 info)
494{
495 const struct iphdr *iph = (const struct iphdr *)skb->data;
496 struct tcphdr *th = (struct tcphdr *)(skb->data + (iph->ihl << 2));
497 struct tcp_sock *tp;
498 const int type = icmp_hdr(skb)->type;
499 const int code = icmp_hdr(skb)->code;
500 struct sock *sk;
501 struct request_sock *fastopen;
502 u32 seq, snd_una;
503 int err;
504 struct net *net = dev_net(skb->dev);
505
506 sk = __inet_lookup_established(net, net->ipv4.tcp_death_row.hashinfo,
507 iph->daddr, th->dest, iph->saddr,
508 ntohs(th->source), inet_iif(skb), 0);
509 if (!sk) {
510 __ICMP_INC_STATS(net, ICMP_MIB_INERRORS);
511 return -ENOENT;
512 }
513 if (sk->sk_state == TCP_TIME_WAIT) {
514 /* To increase the counter of ignored icmps for TCP-AO */
515 tcp_ao_ignore_icmp(sk, AF_INET, type, code);
516 inet_twsk_put(inet_twsk(sk));
517 return 0;
518 }
519 seq = ntohl(th->seq);
520 if (sk->sk_state == TCP_NEW_SYN_RECV) {
521 tcp_req_err(sk, seq, type == ICMP_PARAMETERPROB ||
522 type == ICMP_TIME_EXCEEDED ||
523 (type == ICMP_DEST_UNREACH &&
524 (code == ICMP_NET_UNREACH ||
525 code == ICMP_HOST_UNREACH)));
526 return 0;
527 }
528
529 if (tcp_ao_ignore_icmp(sk, AF_INET, type, code)) {
530 sock_put(sk);
531 return 0;
532 }
533
534 bh_lock_sock(sk);
535 /* If too many ICMPs get dropped on busy
536 * servers this needs to be solved differently.
537 * We do take care of PMTU discovery (RFC1191) special case :
538 * we can receive locally generated ICMP messages while socket is held.
539 */
540 if (sock_owned_by_user(sk)) {
541 if (!(type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED))
542 __NET_INC_STATS(net, LINUX_MIB_LOCKDROPPEDICMPS);
543 }
544 if (sk->sk_state == TCP_CLOSE)
545 goto out;
546
547 if (static_branch_unlikely(&ip4_min_ttl)) {
548 /* min_ttl can be changed concurrently from do_ip_setsockopt() */
549 if (unlikely(iph->ttl < READ_ONCE(inet_sk(sk)->min_ttl))) {
550 __NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP);
551 goto out;
552 }
553 }
554
555 tp = tcp_sk(sk);
556 /* XXX (TFO) - tp->snd_una should be ISN (tcp_create_openreq_child() */
557 fastopen = rcu_dereference(tp->fastopen_rsk);
558 snd_una = fastopen ? tcp_rsk(fastopen)->snt_isn : tp->snd_una;
559 if (sk->sk_state != TCP_LISTEN &&
560 !between(seq, snd_una, tp->snd_nxt)) {
561 __NET_INC_STATS(net, LINUX_MIB_OUTOFWINDOWICMPS);
562 goto out;
563 }
564
565 switch (type) {
566 case ICMP_REDIRECT:
567 if (!sock_owned_by_user(sk))
568 do_redirect(skb, sk);
569 goto out;
570 case ICMP_SOURCE_QUENCH:
571 /* Just silently ignore these. */
572 goto out;
573 case ICMP_PARAMETERPROB:
574 err = EPROTO;
575 break;
576 case ICMP_DEST_UNREACH:
577 if (code > NR_ICMP_UNREACH)
578 goto out;
579
580 if (code == ICMP_FRAG_NEEDED) { /* PMTU discovery (RFC1191) */
581 /* We are not interested in TCP_LISTEN and open_requests
582 * (SYN-ACKs send out by Linux are always <576bytes so
583 * they should go through unfragmented).
584 */
585 if (sk->sk_state == TCP_LISTEN)
586 goto out;
587
588 WRITE_ONCE(tp->mtu_info, info);
589 if (!sock_owned_by_user(sk)) {
590 tcp_v4_mtu_reduced(sk);
591 } else {
592 if (!test_and_set_bit(TCP_MTU_REDUCED_DEFERRED, &sk->sk_tsq_flags))
593 sock_hold(sk);
594 }
595 goto out;
596 }
597
598 err = icmp_err_convert[code].errno;
599 /* check if this ICMP message allows revert of backoff.
600 * (see RFC 6069)
601 */
602 if (!fastopen &&
603 (code == ICMP_NET_UNREACH || code == ICMP_HOST_UNREACH))
604 tcp_ld_RTO_revert(sk, seq);
605 break;
606 case ICMP_TIME_EXCEEDED:
607 err = EHOSTUNREACH;
608 break;
609 default:
610 goto out;
611 }
612
613 switch (sk->sk_state) {
614 case TCP_SYN_SENT:
615 case TCP_SYN_RECV:
616 /* Only in fast or simultaneous open. If a fast open socket is
617 * already accepted it is treated as a connected one below.
618 */
619 if (fastopen && !fastopen->sk)
620 break;
621
622 ip_icmp_error(sk, skb, err, th->dest, info, (u8 *)th);
623
624 if (!sock_owned_by_user(sk))
625 tcp_done_with_error(sk, err);
626 else
627 WRITE_ONCE(sk->sk_err_soft, err);
628 goto out;
629 }
630
631 /* If we've already connected we will keep trying
632 * until we time out, or the user gives up.
633 *
634 * rfc1122 4.2.3.9 allows to consider as hard errors
635 * only PROTO_UNREACH and PORT_UNREACH (well, FRAG_FAILED too,
636 * but it is obsoleted by pmtu discovery).
637 *
638 * Note, that in modern internet, where routing is unreliable
639 * and in each dark corner broken firewalls sit, sending random
640 * errors ordered by their masters even this two messages finally lose
641 * their original sense (even Linux sends invalid PORT_UNREACHs)
642 *
643 * Now we are in compliance with RFCs.
644 * --ANK (980905)
645 */
646
647 if (!sock_owned_by_user(sk) &&
648 inet_test_bit(RECVERR, sk)) {
649 WRITE_ONCE(sk->sk_err, err);
650 sk_error_report(sk);
651 } else { /* Only an error on timeout */
652 WRITE_ONCE(sk->sk_err_soft, err);
653 }
654
655out:
656 bh_unlock_sock(sk);
657 sock_put(sk);
658 return 0;
659}
660
661void __tcp_v4_send_check(struct sk_buff *skb, __be32 saddr, __be32 daddr)
662{
663 struct tcphdr *th = tcp_hdr(skb);
664
665 th->check = ~tcp_v4_check(skb->len, saddr, daddr, 0);
666 skb->csum_start = skb_transport_header(skb) - skb->head;
667 skb->csum_offset = offsetof(struct tcphdr, check);
668}
669
670/* This routine computes an IPv4 TCP checksum. */
671void tcp_v4_send_check(struct sock *sk, struct sk_buff *skb)
672{
673 const struct inet_sock *inet = inet_sk(sk);
674
675 __tcp_v4_send_check(skb, inet->inet_saddr, inet->inet_daddr);
676}
677EXPORT_SYMBOL(tcp_v4_send_check);
678
679#define REPLY_OPTIONS_LEN (MAX_TCP_OPTION_SPACE / sizeof(__be32))
680
681static bool tcp_v4_ao_sign_reset(const struct sock *sk, struct sk_buff *skb,
682 const struct tcp_ao_hdr *aoh,
683 struct ip_reply_arg *arg, struct tcphdr *reply,
684 __be32 reply_options[REPLY_OPTIONS_LEN])
685{
686#ifdef CONFIG_TCP_AO
687 int sdif = tcp_v4_sdif(skb);
688 int dif = inet_iif(skb);
689 int l3index = sdif ? dif : 0;
690 bool allocated_traffic_key;
691 struct tcp_ao_key *key;
692 char *traffic_key;
693 bool drop = true;
694 u32 ao_sne = 0;
695 u8 keyid;
696
697 rcu_read_lock();
698 if (tcp_ao_prepare_reset(sk, skb, aoh, l3index, ntohl(reply->seq),
699 &key, &traffic_key, &allocated_traffic_key,
700 &keyid, &ao_sne))
701 goto out;
702
703 reply_options[0] = htonl((TCPOPT_AO << 24) | (tcp_ao_len(key) << 16) |
704 (aoh->rnext_keyid << 8) | keyid);
705 arg->iov[0].iov_len += tcp_ao_len_aligned(key);
706 reply->doff = arg->iov[0].iov_len / 4;
707
708 if (tcp_ao_hash_hdr(AF_INET, (char *)&reply_options[1],
709 key, traffic_key,
710 (union tcp_ao_addr *)&ip_hdr(skb)->saddr,
711 (union tcp_ao_addr *)&ip_hdr(skb)->daddr,
712 reply, ao_sne))
713 goto out;
714 drop = false;
715out:
716 rcu_read_unlock();
717 if (allocated_traffic_key)
718 kfree(traffic_key);
719 return drop;
720#else
721 return true;
722#endif
723}
724
725/*
726 * This routine will send an RST to the other tcp.
727 *
728 * Someone asks: why I NEVER use socket parameters (TOS, TTL etc.)
729 * for reset.
730 * Answer: if a packet caused RST, it is not for a socket
731 * existing in our system, if it is matched to a socket,
732 * it is just duplicate segment or bug in other side's TCP.
733 * So that we build reply only basing on parameters
734 * arrived with segment.
735 * Exception: precedence violation. We do not implement it in any case.
736 */
737
738static void tcp_v4_send_reset(const struct sock *sk, struct sk_buff *skb,
739 enum sk_rst_reason reason)
740{
741 const struct tcphdr *th = tcp_hdr(skb);
742 struct {
743 struct tcphdr th;
744 __be32 opt[REPLY_OPTIONS_LEN];
745 } rep;
746 const __u8 *md5_hash_location = NULL;
747 const struct tcp_ao_hdr *aoh;
748 struct ip_reply_arg arg;
749#ifdef CONFIG_TCP_MD5SIG
750 struct tcp_md5sig_key *key = NULL;
751 unsigned char newhash[16];
752 struct sock *sk1 = NULL;
753 int genhash;
754#endif
755 u64 transmit_time = 0;
756 struct sock *ctl_sk;
757 struct net *net;
758 u32 txhash = 0;
759
760 /* Never send a reset in response to a reset. */
761 if (th->rst)
762 return;
763
764 /* If sk not NULL, it means we did a successful lookup and incoming
765 * route had to be correct. prequeue might have dropped our dst.
766 */
767 if (!sk && skb_rtable(skb)->rt_type != RTN_LOCAL)
768 return;
769
770 /* Swap the send and the receive. */
771 memset(&rep, 0, sizeof(rep));
772 rep.th.dest = th->source;
773 rep.th.source = th->dest;
774 rep.th.doff = sizeof(struct tcphdr) / 4;
775 rep.th.rst = 1;
776
777 if (th->ack) {
778 rep.th.seq = th->ack_seq;
779 } else {
780 rep.th.ack = 1;
781 rep.th.ack_seq = htonl(ntohl(th->seq) + th->syn + th->fin +
782 skb->len - (th->doff << 2));
783 }
784
785 memset(&arg, 0, sizeof(arg));
786 arg.iov[0].iov_base = (unsigned char *)&rep;
787 arg.iov[0].iov_len = sizeof(rep.th);
788
789 net = sk ? sock_net(sk) : dev_net(skb_dst(skb)->dev);
790
791 /* Invalid TCP option size or twice included auth */
792 if (tcp_parse_auth_options(tcp_hdr(skb), &md5_hash_location, &aoh))
793 return;
794
795 if (aoh && tcp_v4_ao_sign_reset(sk, skb, aoh, &arg, &rep.th, rep.opt))
796 return;
797
798#ifdef CONFIG_TCP_MD5SIG
799 rcu_read_lock();
800 if (sk && sk_fullsock(sk)) {
801 const union tcp_md5_addr *addr;
802 int l3index;
803
804 /* sdif set, means packet ingressed via a device
805 * in an L3 domain and inet_iif is set to it.
806 */
807 l3index = tcp_v4_sdif(skb) ? inet_iif(skb) : 0;
808 addr = (union tcp_md5_addr *)&ip_hdr(skb)->saddr;
809 key = tcp_md5_do_lookup(sk, l3index, addr, AF_INET);
810 } else if (md5_hash_location) {
811 const union tcp_md5_addr *addr;
812 int sdif = tcp_v4_sdif(skb);
813 int dif = inet_iif(skb);
814 int l3index;
815
816 /*
817 * active side is lost. Try to find listening socket through
818 * source port, and then find md5 key through listening socket.
819 * we are not loose security here:
820 * Incoming packet is checked with md5 hash with finding key,
821 * no RST generated if md5 hash doesn't match.
822 */
823 sk1 = __inet_lookup_listener(net, net->ipv4.tcp_death_row.hashinfo,
824 NULL, 0, ip_hdr(skb)->saddr,
825 th->source, ip_hdr(skb)->daddr,
826 ntohs(th->source), dif, sdif);
827 /* don't send rst if it can't find key */
828 if (!sk1)
829 goto out;
830
831 /* sdif set, means packet ingressed via a device
832 * in an L3 domain and dif is set to it.
833 */
834 l3index = sdif ? dif : 0;
835 addr = (union tcp_md5_addr *)&ip_hdr(skb)->saddr;
836 key = tcp_md5_do_lookup(sk1, l3index, addr, AF_INET);
837 if (!key)
838 goto out;
839
840
841 genhash = tcp_v4_md5_hash_skb(newhash, key, NULL, skb);
842 if (genhash || memcmp(md5_hash_location, newhash, 16) != 0)
843 goto out;
844
845 }
846
847 if (key) {
848 rep.opt[0] = htonl((TCPOPT_NOP << 24) |
849 (TCPOPT_NOP << 16) |
850 (TCPOPT_MD5SIG << 8) |
851 TCPOLEN_MD5SIG);
852 /* Update length and the length the header thinks exists */
853 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED;
854 rep.th.doff = arg.iov[0].iov_len / 4;
855
856 tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[1],
857 key, ip_hdr(skb)->saddr,
858 ip_hdr(skb)->daddr, &rep.th);
859 }
860#endif
861 /* Can't co-exist with TCPMD5, hence check rep.opt[0] */
862 if (rep.opt[0] == 0) {
863 __be32 mrst = mptcp_reset_option(skb);
864
865 if (mrst) {
866 rep.opt[0] = mrst;
867 arg.iov[0].iov_len += sizeof(mrst);
868 rep.th.doff = arg.iov[0].iov_len / 4;
869 }
870 }
871
872 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
873 ip_hdr(skb)->saddr, /* XXX */
874 arg.iov[0].iov_len, IPPROTO_TCP, 0);
875 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
876 arg.flags = (sk && inet_sk_transparent(sk)) ? IP_REPLY_ARG_NOSRCCHECK : 0;
877
878 /* When socket is gone, all binding information is lost.
879 * routing might fail in this case. No choice here, if we choose to force
880 * input interface, we will misroute in case of asymmetric route.
881 */
882 if (sk)
883 arg.bound_dev_if = sk->sk_bound_dev_if;
884
885 trace_tcp_send_reset(sk, skb, reason);
886
887 BUILD_BUG_ON(offsetof(struct sock, sk_bound_dev_if) !=
888 offsetof(struct inet_timewait_sock, tw_bound_dev_if));
889
890 arg.tos = ip_hdr(skb)->tos;
891 arg.uid = sock_net_uid(net, sk && sk_fullsock(sk) ? sk : NULL);
892 local_bh_disable();
893 local_lock_nested_bh(&ipv4_tcp_sk.bh_lock);
894 ctl_sk = this_cpu_read(ipv4_tcp_sk.sock);
895
896 sock_net_set(ctl_sk, net);
897 if (sk) {
898 ctl_sk->sk_mark = (sk->sk_state == TCP_TIME_WAIT) ?
899 inet_twsk(sk)->tw_mark : READ_ONCE(sk->sk_mark);
900 ctl_sk->sk_priority = (sk->sk_state == TCP_TIME_WAIT) ?
901 inet_twsk(sk)->tw_priority : READ_ONCE(sk->sk_priority);
902 transmit_time = tcp_transmit_time(sk);
903 xfrm_sk_clone_policy(ctl_sk, sk);
904 txhash = (sk->sk_state == TCP_TIME_WAIT) ?
905 inet_twsk(sk)->tw_txhash : sk->sk_txhash;
906 } else {
907 ctl_sk->sk_mark = 0;
908 ctl_sk->sk_priority = 0;
909 }
910 ip_send_unicast_reply(ctl_sk, sk,
911 skb, &TCP_SKB_CB(skb)->header.h4.opt,
912 ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
913 &arg, arg.iov[0].iov_len,
914 transmit_time, txhash);
915
916 xfrm_sk_free_policy(ctl_sk);
917 sock_net_set(ctl_sk, &init_net);
918 __TCP_INC_STATS(net, TCP_MIB_OUTSEGS);
919 __TCP_INC_STATS(net, TCP_MIB_OUTRSTS);
920 local_unlock_nested_bh(&ipv4_tcp_sk.bh_lock);
921 local_bh_enable();
922
923#ifdef CONFIG_TCP_MD5SIG
924out:
925 rcu_read_unlock();
926#endif
927}
928
929/* The code following below sending ACKs in SYN-RECV and TIME-WAIT states
930 outside socket context is ugly, certainly. What can I do?
931 */
932
933static void tcp_v4_send_ack(const struct sock *sk,
934 struct sk_buff *skb, u32 seq, u32 ack,
935 u32 win, u32 tsval, u32 tsecr, int oif,
936 struct tcp_key *key,
937 int reply_flags, u8 tos, u32 txhash)
938{
939 const struct tcphdr *th = tcp_hdr(skb);
940 struct {
941 struct tcphdr th;
942 __be32 opt[(MAX_TCP_OPTION_SPACE >> 2)];
943 } rep;
944 struct net *net = sock_net(sk);
945 struct ip_reply_arg arg;
946 struct sock *ctl_sk;
947 u64 transmit_time;
948
949 memset(&rep.th, 0, sizeof(struct tcphdr));
950 memset(&arg, 0, sizeof(arg));
951
952 arg.iov[0].iov_base = (unsigned char *)&rep;
953 arg.iov[0].iov_len = sizeof(rep.th);
954 if (tsecr) {
955 rep.opt[0] = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
956 (TCPOPT_TIMESTAMP << 8) |
957 TCPOLEN_TIMESTAMP);
958 rep.opt[1] = htonl(tsval);
959 rep.opt[2] = htonl(tsecr);
960 arg.iov[0].iov_len += TCPOLEN_TSTAMP_ALIGNED;
961 }
962
963 /* Swap the send and the receive. */
964 rep.th.dest = th->source;
965 rep.th.source = th->dest;
966 rep.th.doff = arg.iov[0].iov_len / 4;
967 rep.th.seq = htonl(seq);
968 rep.th.ack_seq = htonl(ack);
969 rep.th.ack = 1;
970 rep.th.window = htons(win);
971
972#ifdef CONFIG_TCP_MD5SIG
973 if (tcp_key_is_md5(key)) {
974 int offset = (tsecr) ? 3 : 0;
975
976 rep.opt[offset++] = htonl((TCPOPT_NOP << 24) |
977 (TCPOPT_NOP << 16) |
978 (TCPOPT_MD5SIG << 8) |
979 TCPOLEN_MD5SIG);
980 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED;
981 rep.th.doff = arg.iov[0].iov_len/4;
982
983 tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[offset],
984 key->md5_key, ip_hdr(skb)->saddr,
985 ip_hdr(skb)->daddr, &rep.th);
986 }
987#endif
988#ifdef CONFIG_TCP_AO
989 if (tcp_key_is_ao(key)) {
990 int offset = (tsecr) ? 3 : 0;
991
992 rep.opt[offset++] = htonl((TCPOPT_AO << 24) |
993 (tcp_ao_len(key->ao_key) << 16) |
994 (key->ao_key->sndid << 8) |
995 key->rcv_next);
996 arg.iov[0].iov_len += tcp_ao_len_aligned(key->ao_key);
997 rep.th.doff = arg.iov[0].iov_len / 4;
998
999 tcp_ao_hash_hdr(AF_INET, (char *)&rep.opt[offset],
1000 key->ao_key, key->traffic_key,
1001 (union tcp_ao_addr *)&ip_hdr(skb)->saddr,
1002 (union tcp_ao_addr *)&ip_hdr(skb)->daddr,
1003 &rep.th, key->sne);
1004 }
1005#endif
1006 arg.flags = reply_flags;
1007 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
1008 ip_hdr(skb)->saddr, /* XXX */
1009 arg.iov[0].iov_len, IPPROTO_TCP, 0);
1010 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
1011 if (oif)
1012 arg.bound_dev_if = oif;
1013 arg.tos = tos;
1014 arg.uid = sock_net_uid(net, sk_fullsock(sk) ? sk : NULL);
1015 local_bh_disable();
1016 local_lock_nested_bh(&ipv4_tcp_sk.bh_lock);
1017 ctl_sk = this_cpu_read(ipv4_tcp_sk.sock);
1018 sock_net_set(ctl_sk, net);
1019 ctl_sk->sk_mark = (sk->sk_state == TCP_TIME_WAIT) ?
1020 inet_twsk(sk)->tw_mark : READ_ONCE(sk->sk_mark);
1021 ctl_sk->sk_priority = (sk->sk_state == TCP_TIME_WAIT) ?
1022 inet_twsk(sk)->tw_priority : READ_ONCE(sk->sk_priority);
1023 transmit_time = tcp_transmit_time(sk);
1024 ip_send_unicast_reply(ctl_sk, sk,
1025 skb, &TCP_SKB_CB(skb)->header.h4.opt,
1026 ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
1027 &arg, arg.iov[0].iov_len,
1028 transmit_time, txhash);
1029
1030 sock_net_set(ctl_sk, &init_net);
1031 __TCP_INC_STATS(net, TCP_MIB_OUTSEGS);
1032 local_unlock_nested_bh(&ipv4_tcp_sk.bh_lock);
1033 local_bh_enable();
1034}
1035
1036static void tcp_v4_timewait_ack(struct sock *sk, struct sk_buff *skb)
1037{
1038 struct inet_timewait_sock *tw = inet_twsk(sk);
1039 struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
1040 struct tcp_key key = {};
1041#ifdef CONFIG_TCP_AO
1042 struct tcp_ao_info *ao_info;
1043
1044 if (static_branch_unlikely(&tcp_ao_needed.key)) {
1045 /* FIXME: the segment to-be-acked is not verified yet */
1046 ao_info = rcu_dereference(tcptw->ao_info);
1047 if (ao_info) {
1048 const struct tcp_ao_hdr *aoh;
1049
1050 if (tcp_parse_auth_options(tcp_hdr(skb), NULL, &aoh)) {
1051 inet_twsk_put(tw);
1052 return;
1053 }
1054
1055 if (aoh)
1056 key.ao_key = tcp_ao_established_key(sk, ao_info,
1057 aoh->rnext_keyid, -1);
1058 }
1059 }
1060 if (key.ao_key) {
1061 struct tcp_ao_key *rnext_key;
1062
1063 key.traffic_key = snd_other_key(key.ao_key);
1064 key.sne = READ_ONCE(ao_info->snd_sne);
1065 rnext_key = READ_ONCE(ao_info->rnext_key);
1066 key.rcv_next = rnext_key->rcvid;
1067 key.type = TCP_KEY_AO;
1068#else
1069 if (0) {
1070#endif
1071 } else if (static_branch_tcp_md5()) {
1072 key.md5_key = tcp_twsk_md5_key(tcptw);
1073 if (key.md5_key)
1074 key.type = TCP_KEY_MD5;
1075 }
1076
1077 tcp_v4_send_ack(sk, skb,
1078 tcptw->tw_snd_nxt, READ_ONCE(tcptw->tw_rcv_nxt),
1079 tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
1080 tcp_tw_tsval(tcptw),
1081 READ_ONCE(tcptw->tw_ts_recent),
1082 tw->tw_bound_dev_if, &key,
1083 tw->tw_transparent ? IP_REPLY_ARG_NOSRCCHECK : 0,
1084 tw->tw_tos,
1085 tw->tw_txhash);
1086
1087 inet_twsk_put(tw);
1088}
1089
1090static void tcp_v4_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb,
1091 struct request_sock *req)
1092{
1093 struct tcp_key key = {};
1094
1095 /* sk->sk_state == TCP_LISTEN -> for regular TCP_SYN_RECV
1096 * sk->sk_state == TCP_SYN_RECV -> for Fast Open.
1097 */
1098 u32 seq = (sk->sk_state == TCP_LISTEN) ? tcp_rsk(req)->snt_isn + 1 :
1099 tcp_sk(sk)->snd_nxt;
1100
1101#ifdef CONFIG_TCP_AO
1102 if (static_branch_unlikely(&tcp_ao_needed.key) &&
1103 tcp_rsk_used_ao(req)) {
1104 const union tcp_md5_addr *addr;
1105 const struct tcp_ao_hdr *aoh;
1106 int l3index;
1107
1108 /* Invalid TCP option size or twice included auth */
1109 if (tcp_parse_auth_options(tcp_hdr(skb), NULL, &aoh))
1110 return;
1111 if (!aoh)
1112 return;
1113
1114 addr = (union tcp_md5_addr *)&ip_hdr(skb)->saddr;
1115 l3index = tcp_v4_sdif(skb) ? inet_iif(skb) : 0;
1116 key.ao_key = tcp_ao_do_lookup(sk, l3index, addr, AF_INET,
1117 aoh->rnext_keyid, -1);
1118 if (unlikely(!key.ao_key)) {
1119 /* Send ACK with any matching MKT for the peer */
1120 key.ao_key = tcp_ao_do_lookup(sk, l3index, addr, AF_INET, -1, -1);
1121 /* Matching key disappeared (user removed the key?)
1122 * let the handshake timeout.
1123 */
1124 if (!key.ao_key) {
1125 net_info_ratelimited("TCP-AO key for (%pI4, %d)->(%pI4, %d) suddenly disappeared, won't ACK new connection\n",
1126 addr,
1127 ntohs(tcp_hdr(skb)->source),
1128 &ip_hdr(skb)->daddr,
1129 ntohs(tcp_hdr(skb)->dest));
1130 return;
1131 }
1132 }
1133 key.traffic_key = kmalloc(tcp_ao_digest_size(key.ao_key), GFP_ATOMIC);
1134 if (!key.traffic_key)
1135 return;
1136
1137 key.type = TCP_KEY_AO;
1138 key.rcv_next = aoh->keyid;
1139 tcp_v4_ao_calc_key_rsk(key.ao_key, key.traffic_key, req);
1140#else
1141 if (0) {
1142#endif
1143 } else if (static_branch_tcp_md5()) {
1144 const union tcp_md5_addr *addr;
1145 int l3index;
1146
1147 addr = (union tcp_md5_addr *)&ip_hdr(skb)->saddr;
1148 l3index = tcp_v4_sdif(skb) ? inet_iif(skb) : 0;
1149 key.md5_key = tcp_md5_do_lookup(sk, l3index, addr, AF_INET);
1150 if (key.md5_key)
1151 key.type = TCP_KEY_MD5;
1152 }
1153
1154 tcp_v4_send_ack(sk, skb, seq,
1155 tcp_rsk(req)->rcv_nxt,
1156 tcp_synack_window(req) >> inet_rsk(req)->rcv_wscale,
1157 tcp_rsk_tsval(tcp_rsk(req)),
1158 READ_ONCE(req->ts_recent),
1159 0, &key,
1160 inet_rsk(req)->no_srccheck ? IP_REPLY_ARG_NOSRCCHECK : 0,
1161 ip_hdr(skb)->tos,
1162 READ_ONCE(tcp_rsk(req)->txhash));
1163 if (tcp_key_is_ao(&key))
1164 kfree(key.traffic_key);
1165}
1166
1167/*
1168 * Send a SYN-ACK after having received a SYN.
1169 * This still operates on a request_sock only, not on a big
1170 * socket.
1171 */
1172static int tcp_v4_send_synack(const struct sock *sk, struct dst_entry *dst,
1173 struct flowi *fl,
1174 struct request_sock *req,
1175 struct tcp_fastopen_cookie *foc,
1176 enum tcp_synack_type synack_type,
1177 struct sk_buff *syn_skb)
1178{
1179 const struct inet_request_sock *ireq = inet_rsk(req);
1180 struct flowi4 fl4;
1181 int err = -1;
1182 struct sk_buff *skb;
1183 u8 tos;
1184
1185 /* First, grab a route. */
1186 if (!dst && (dst = inet_csk_route_req(sk, &fl4, req)) == NULL)
1187 return -1;
1188
1189 skb = tcp_make_synack(sk, dst, req, foc, synack_type, syn_skb);
1190
1191 if (skb) {
1192 __tcp_v4_send_check(skb, ireq->ir_loc_addr, ireq->ir_rmt_addr);
1193
1194 tos = READ_ONCE(inet_sk(sk)->tos);
1195
1196 if (READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_reflect_tos))
1197 tos = (tcp_rsk(req)->syn_tos & ~INET_ECN_MASK) |
1198 (tos & INET_ECN_MASK);
1199
1200 if (!INET_ECN_is_capable(tos) &&
1201 tcp_bpf_ca_needs_ecn((struct sock *)req))
1202 tos |= INET_ECN_ECT_0;
1203
1204 rcu_read_lock();
1205 err = ip_build_and_send_pkt(skb, sk, ireq->ir_loc_addr,
1206 ireq->ir_rmt_addr,
1207 rcu_dereference(ireq->ireq_opt),
1208 tos);
1209 rcu_read_unlock();
1210 err = net_xmit_eval(err);
1211 }
1212
1213 return err;
1214}
1215
1216/*
1217 * IPv4 request_sock destructor.
1218 */
1219static void tcp_v4_reqsk_destructor(struct request_sock *req)
1220{
1221 kfree(rcu_dereference_protected(inet_rsk(req)->ireq_opt, 1));
1222}
1223
1224#ifdef CONFIG_TCP_MD5SIG
1225/*
1226 * RFC2385 MD5 checksumming requires a mapping of
1227 * IP address->MD5 Key.
1228 * We need to maintain these in the sk structure.
1229 */
1230
1231DEFINE_STATIC_KEY_DEFERRED_FALSE(tcp_md5_needed, HZ);
1232EXPORT_SYMBOL(tcp_md5_needed);
1233
1234static bool better_md5_match(struct tcp_md5sig_key *old, struct tcp_md5sig_key *new)
1235{
1236 if (!old)
1237 return true;
1238
1239 /* l3index always overrides non-l3index */
1240 if (old->l3index && new->l3index == 0)
1241 return false;
1242 if (old->l3index == 0 && new->l3index)
1243 return true;
1244
1245 return old->prefixlen < new->prefixlen;
1246}
1247
1248/* Find the Key structure for an address. */
1249struct tcp_md5sig_key *__tcp_md5_do_lookup(const struct sock *sk, int l3index,
1250 const union tcp_md5_addr *addr,
1251 int family, bool any_l3index)
1252{
1253 const struct tcp_sock *tp = tcp_sk(sk);
1254 struct tcp_md5sig_key *key;
1255 const struct tcp_md5sig_info *md5sig;
1256 __be32 mask;
1257 struct tcp_md5sig_key *best_match = NULL;
1258 bool match;
1259
1260 /* caller either holds rcu_read_lock() or socket lock */
1261 md5sig = rcu_dereference_check(tp->md5sig_info,
1262 lockdep_sock_is_held(sk));
1263 if (!md5sig)
1264 return NULL;
1265
1266 hlist_for_each_entry_rcu(key, &md5sig->head, node,
1267 lockdep_sock_is_held(sk)) {
1268 if (key->family != family)
1269 continue;
1270 if (!any_l3index && key->flags & TCP_MD5SIG_FLAG_IFINDEX &&
1271 key->l3index != l3index)
1272 continue;
1273 if (family == AF_INET) {
1274 mask = inet_make_mask(key->prefixlen);
1275 match = (key->addr.a4.s_addr & mask) ==
1276 (addr->a4.s_addr & mask);
1277#if IS_ENABLED(CONFIG_IPV6)
1278 } else if (family == AF_INET6) {
1279 match = ipv6_prefix_equal(&key->addr.a6, &addr->a6,
1280 key->prefixlen);
1281#endif
1282 } else {
1283 match = false;
1284 }
1285
1286 if (match && better_md5_match(best_match, key))
1287 best_match = key;
1288 }
1289 return best_match;
1290}
1291EXPORT_SYMBOL(__tcp_md5_do_lookup);
1292
1293static struct tcp_md5sig_key *tcp_md5_do_lookup_exact(const struct sock *sk,
1294 const union tcp_md5_addr *addr,
1295 int family, u8 prefixlen,
1296 int l3index, u8 flags)
1297{
1298 const struct tcp_sock *tp = tcp_sk(sk);
1299 struct tcp_md5sig_key *key;
1300 unsigned int size = sizeof(struct in_addr);
1301 const struct tcp_md5sig_info *md5sig;
1302
1303 /* caller either holds rcu_read_lock() or socket lock */
1304 md5sig = rcu_dereference_check(tp->md5sig_info,
1305 lockdep_sock_is_held(sk));
1306 if (!md5sig)
1307 return NULL;
1308#if IS_ENABLED(CONFIG_IPV6)
1309 if (family == AF_INET6)
1310 size = sizeof(struct in6_addr);
1311#endif
1312 hlist_for_each_entry_rcu(key, &md5sig->head, node,
1313 lockdep_sock_is_held(sk)) {
1314 if (key->family != family)
1315 continue;
1316 if ((key->flags & TCP_MD5SIG_FLAG_IFINDEX) != (flags & TCP_MD5SIG_FLAG_IFINDEX))
1317 continue;
1318 if (key->l3index != l3index)
1319 continue;
1320 if (!memcmp(&key->addr, addr, size) &&
1321 key->prefixlen == prefixlen)
1322 return key;
1323 }
1324 return NULL;
1325}
1326
1327struct tcp_md5sig_key *tcp_v4_md5_lookup(const struct sock *sk,
1328 const struct sock *addr_sk)
1329{
1330 const union tcp_md5_addr *addr;
1331 int l3index;
1332
1333 l3index = l3mdev_master_ifindex_by_index(sock_net(sk),
1334 addr_sk->sk_bound_dev_if);
1335 addr = (const union tcp_md5_addr *)&addr_sk->sk_daddr;
1336 return tcp_md5_do_lookup(sk, l3index, addr, AF_INET);
1337}
1338EXPORT_SYMBOL(tcp_v4_md5_lookup);
1339
1340static int tcp_md5sig_info_add(struct sock *sk, gfp_t gfp)
1341{
1342 struct tcp_sock *tp = tcp_sk(sk);
1343 struct tcp_md5sig_info *md5sig;
1344
1345 md5sig = kmalloc(sizeof(*md5sig), gfp);
1346 if (!md5sig)
1347 return -ENOMEM;
1348
1349 sk_gso_disable(sk);
1350 INIT_HLIST_HEAD(&md5sig->head);
1351 rcu_assign_pointer(tp->md5sig_info, md5sig);
1352 return 0;
1353}
1354
1355/* This can be called on a newly created socket, from other files */
1356static int __tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr,
1357 int family, u8 prefixlen, int l3index, u8 flags,
1358 const u8 *newkey, u8 newkeylen, gfp_t gfp)
1359{
1360 /* Add Key to the list */
1361 struct tcp_md5sig_key *key;
1362 struct tcp_sock *tp = tcp_sk(sk);
1363 struct tcp_md5sig_info *md5sig;
1364
1365 key = tcp_md5_do_lookup_exact(sk, addr, family, prefixlen, l3index, flags);
1366 if (key) {
1367 /* Pre-existing entry - just update that one.
1368 * Note that the key might be used concurrently.
1369 * data_race() is telling kcsan that we do not care of
1370 * key mismatches, since changing MD5 key on live flows
1371 * can lead to packet drops.
1372 */
1373 data_race(memcpy(key->key, newkey, newkeylen));
1374
1375 /* Pairs with READ_ONCE() in tcp_md5_hash_key().
1376 * Also note that a reader could catch new key->keylen value
1377 * but old key->key[], this is the reason we use __GFP_ZERO
1378 * at sock_kmalloc() time below these lines.
1379 */
1380 WRITE_ONCE(key->keylen, newkeylen);
1381
1382 return 0;
1383 }
1384
1385 md5sig = rcu_dereference_protected(tp->md5sig_info,
1386 lockdep_sock_is_held(sk));
1387
1388 key = sock_kmalloc(sk, sizeof(*key), gfp | __GFP_ZERO);
1389 if (!key)
1390 return -ENOMEM;
1391
1392 memcpy(key->key, newkey, newkeylen);
1393 key->keylen = newkeylen;
1394 key->family = family;
1395 key->prefixlen = prefixlen;
1396 key->l3index = l3index;
1397 key->flags = flags;
1398 memcpy(&key->addr, addr,
1399 (IS_ENABLED(CONFIG_IPV6) && family == AF_INET6) ? sizeof(struct in6_addr) :
1400 sizeof(struct in_addr));
1401 hlist_add_head_rcu(&key->node, &md5sig->head);
1402 return 0;
1403}
1404
1405int tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr,
1406 int family, u8 prefixlen, int l3index, u8 flags,
1407 const u8 *newkey, u8 newkeylen)
1408{
1409 struct tcp_sock *tp = tcp_sk(sk);
1410
1411 if (!rcu_dereference_protected(tp->md5sig_info, lockdep_sock_is_held(sk))) {
1412 if (tcp_md5_alloc_sigpool())
1413 return -ENOMEM;
1414
1415 if (tcp_md5sig_info_add(sk, GFP_KERNEL)) {
1416 tcp_md5_release_sigpool();
1417 return -ENOMEM;
1418 }
1419
1420 if (!static_branch_inc(&tcp_md5_needed.key)) {
1421 struct tcp_md5sig_info *md5sig;
1422
1423 md5sig = rcu_dereference_protected(tp->md5sig_info, lockdep_sock_is_held(sk));
1424 rcu_assign_pointer(tp->md5sig_info, NULL);
1425 kfree_rcu(md5sig, rcu);
1426 tcp_md5_release_sigpool();
1427 return -EUSERS;
1428 }
1429 }
1430
1431 return __tcp_md5_do_add(sk, addr, family, prefixlen, l3index, flags,
1432 newkey, newkeylen, GFP_KERNEL);
1433}
1434EXPORT_SYMBOL(tcp_md5_do_add);
1435
1436int tcp_md5_key_copy(struct sock *sk, const union tcp_md5_addr *addr,
1437 int family, u8 prefixlen, int l3index,
1438 struct tcp_md5sig_key *key)
1439{
1440 struct tcp_sock *tp = tcp_sk(sk);
1441
1442 if (!rcu_dereference_protected(tp->md5sig_info, lockdep_sock_is_held(sk))) {
1443 tcp_md5_add_sigpool();
1444
1445 if (tcp_md5sig_info_add(sk, sk_gfp_mask(sk, GFP_ATOMIC))) {
1446 tcp_md5_release_sigpool();
1447 return -ENOMEM;
1448 }
1449
1450 if (!static_key_fast_inc_not_disabled(&tcp_md5_needed.key.key)) {
1451 struct tcp_md5sig_info *md5sig;
1452
1453 md5sig = rcu_dereference_protected(tp->md5sig_info, lockdep_sock_is_held(sk));
1454 net_warn_ratelimited("Too many TCP-MD5 keys in the system\n");
1455 rcu_assign_pointer(tp->md5sig_info, NULL);
1456 kfree_rcu(md5sig, rcu);
1457 tcp_md5_release_sigpool();
1458 return -EUSERS;
1459 }
1460 }
1461
1462 return __tcp_md5_do_add(sk, addr, family, prefixlen, l3index,
1463 key->flags, key->key, key->keylen,
1464 sk_gfp_mask(sk, GFP_ATOMIC));
1465}
1466EXPORT_SYMBOL(tcp_md5_key_copy);
1467
1468int tcp_md5_do_del(struct sock *sk, const union tcp_md5_addr *addr, int family,
1469 u8 prefixlen, int l3index, u8 flags)
1470{
1471 struct tcp_md5sig_key *key;
1472
1473 key = tcp_md5_do_lookup_exact(sk, addr, family, prefixlen, l3index, flags);
1474 if (!key)
1475 return -ENOENT;
1476 hlist_del_rcu(&key->node);
1477 atomic_sub(sizeof(*key), &sk->sk_omem_alloc);
1478 kfree_rcu(key, rcu);
1479 return 0;
1480}
1481EXPORT_SYMBOL(tcp_md5_do_del);
1482
1483void tcp_clear_md5_list(struct sock *sk)
1484{
1485 struct tcp_sock *tp = tcp_sk(sk);
1486 struct tcp_md5sig_key *key;
1487 struct hlist_node *n;
1488 struct tcp_md5sig_info *md5sig;
1489
1490 md5sig = rcu_dereference_protected(tp->md5sig_info, 1);
1491
1492 hlist_for_each_entry_safe(key, n, &md5sig->head, node) {
1493 hlist_del_rcu(&key->node);
1494 atomic_sub(sizeof(*key), &sk->sk_omem_alloc);
1495 kfree_rcu(key, rcu);
1496 }
1497}
1498
1499static int tcp_v4_parse_md5_keys(struct sock *sk, int optname,
1500 sockptr_t optval, int optlen)
1501{
1502 struct tcp_md5sig cmd;
1503 struct sockaddr_in *sin = (struct sockaddr_in *)&cmd.tcpm_addr;
1504 const union tcp_md5_addr *addr;
1505 u8 prefixlen = 32;
1506 int l3index = 0;
1507 bool l3flag;
1508 u8 flags;
1509
1510 if (optlen < sizeof(cmd))
1511 return -EINVAL;
1512
1513 if (copy_from_sockptr(&cmd, optval, sizeof(cmd)))
1514 return -EFAULT;
1515
1516 if (sin->sin_family != AF_INET)
1517 return -EINVAL;
1518
1519 flags = cmd.tcpm_flags & TCP_MD5SIG_FLAG_IFINDEX;
1520 l3flag = cmd.tcpm_flags & TCP_MD5SIG_FLAG_IFINDEX;
1521
1522 if (optname == TCP_MD5SIG_EXT &&
1523 cmd.tcpm_flags & TCP_MD5SIG_FLAG_PREFIX) {
1524 prefixlen = cmd.tcpm_prefixlen;
1525 if (prefixlen > 32)
1526 return -EINVAL;
1527 }
1528
1529 if (optname == TCP_MD5SIG_EXT && cmd.tcpm_ifindex &&
1530 cmd.tcpm_flags & TCP_MD5SIG_FLAG_IFINDEX) {
1531 struct net_device *dev;
1532
1533 rcu_read_lock();
1534 dev = dev_get_by_index_rcu(sock_net(sk), cmd.tcpm_ifindex);
1535 if (dev && netif_is_l3_master(dev))
1536 l3index = dev->ifindex;
1537
1538 rcu_read_unlock();
1539
1540 /* ok to reference set/not set outside of rcu;
1541 * right now device MUST be an L3 master
1542 */
1543 if (!dev || !l3index)
1544 return -EINVAL;
1545 }
1546
1547 addr = (union tcp_md5_addr *)&sin->sin_addr.s_addr;
1548
1549 if (!cmd.tcpm_keylen)
1550 return tcp_md5_do_del(sk, addr, AF_INET, prefixlen, l3index, flags);
1551
1552 if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN)
1553 return -EINVAL;
1554
1555 /* Don't allow keys for peers that have a matching TCP-AO key.
1556 * See the comment in tcp_ao_add_cmd()
1557 */
1558 if (tcp_ao_required(sk, addr, AF_INET, l3flag ? l3index : -1, false))
1559 return -EKEYREJECTED;
1560
1561 return tcp_md5_do_add(sk, addr, AF_INET, prefixlen, l3index, flags,
1562 cmd.tcpm_key, cmd.tcpm_keylen);
1563}
1564
1565static int tcp_v4_md5_hash_headers(struct tcp_sigpool *hp,
1566 __be32 daddr, __be32 saddr,
1567 const struct tcphdr *th, int nbytes)
1568{
1569 struct tcp4_pseudohdr *bp;
1570 struct scatterlist sg;
1571 struct tcphdr *_th;
1572
1573 bp = hp->scratch;
1574 bp->saddr = saddr;
1575 bp->daddr = daddr;
1576 bp->pad = 0;
1577 bp->protocol = IPPROTO_TCP;
1578 bp->len = cpu_to_be16(nbytes);
1579
1580 _th = (struct tcphdr *)(bp + 1);
1581 memcpy(_th, th, sizeof(*th));
1582 _th->check = 0;
1583
1584 sg_init_one(&sg, bp, sizeof(*bp) + sizeof(*th));
1585 ahash_request_set_crypt(hp->req, &sg, NULL,
1586 sizeof(*bp) + sizeof(*th));
1587 return crypto_ahash_update(hp->req);
1588}
1589
1590static int tcp_v4_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key,
1591 __be32 daddr, __be32 saddr, const struct tcphdr *th)
1592{
1593 struct tcp_sigpool hp;
1594
1595 if (tcp_sigpool_start(tcp_md5_sigpool_id, &hp))
1596 goto clear_hash_nostart;
1597
1598 if (crypto_ahash_init(hp.req))
1599 goto clear_hash;
1600 if (tcp_v4_md5_hash_headers(&hp, daddr, saddr, th, th->doff << 2))
1601 goto clear_hash;
1602 if (tcp_md5_hash_key(&hp, key))
1603 goto clear_hash;
1604 ahash_request_set_crypt(hp.req, NULL, md5_hash, 0);
1605 if (crypto_ahash_final(hp.req))
1606 goto clear_hash;
1607
1608 tcp_sigpool_end(&hp);
1609 return 0;
1610
1611clear_hash:
1612 tcp_sigpool_end(&hp);
1613clear_hash_nostart:
1614 memset(md5_hash, 0, 16);
1615 return 1;
1616}
1617
1618int tcp_v4_md5_hash_skb(char *md5_hash, const struct tcp_md5sig_key *key,
1619 const struct sock *sk,
1620 const struct sk_buff *skb)
1621{
1622 const struct tcphdr *th = tcp_hdr(skb);
1623 struct tcp_sigpool hp;
1624 __be32 saddr, daddr;
1625
1626 if (sk) { /* valid for establish/request sockets */
1627 saddr = sk->sk_rcv_saddr;
1628 daddr = sk->sk_daddr;
1629 } else {
1630 const struct iphdr *iph = ip_hdr(skb);
1631 saddr = iph->saddr;
1632 daddr = iph->daddr;
1633 }
1634
1635 if (tcp_sigpool_start(tcp_md5_sigpool_id, &hp))
1636 goto clear_hash_nostart;
1637
1638 if (crypto_ahash_init(hp.req))
1639 goto clear_hash;
1640
1641 if (tcp_v4_md5_hash_headers(&hp, daddr, saddr, th, skb->len))
1642 goto clear_hash;
1643 if (tcp_sigpool_hash_skb_data(&hp, skb, th->doff << 2))
1644 goto clear_hash;
1645 if (tcp_md5_hash_key(&hp, key))
1646 goto clear_hash;
1647 ahash_request_set_crypt(hp.req, NULL, md5_hash, 0);
1648 if (crypto_ahash_final(hp.req))
1649 goto clear_hash;
1650
1651 tcp_sigpool_end(&hp);
1652 return 0;
1653
1654clear_hash:
1655 tcp_sigpool_end(&hp);
1656clear_hash_nostart:
1657 memset(md5_hash, 0, 16);
1658 return 1;
1659}
1660EXPORT_SYMBOL(tcp_v4_md5_hash_skb);
1661
1662#endif
1663
1664static void tcp_v4_init_req(struct request_sock *req,
1665 const struct sock *sk_listener,
1666 struct sk_buff *skb)
1667{
1668 struct inet_request_sock *ireq = inet_rsk(req);
1669 struct net *net = sock_net(sk_listener);
1670
1671 sk_rcv_saddr_set(req_to_sk(req), ip_hdr(skb)->daddr);
1672 sk_daddr_set(req_to_sk(req), ip_hdr(skb)->saddr);
1673 RCU_INIT_POINTER(ireq->ireq_opt, tcp_v4_save_options(net, skb));
1674}
1675
1676static struct dst_entry *tcp_v4_route_req(const struct sock *sk,
1677 struct sk_buff *skb,
1678 struct flowi *fl,
1679 struct request_sock *req,
1680 u32 tw_isn)
1681{
1682 tcp_v4_init_req(req, sk, skb);
1683
1684 if (security_inet_conn_request(sk, skb, req))
1685 return NULL;
1686
1687 return inet_csk_route_req(sk, &fl->u.ip4, req);
1688}
1689
1690struct request_sock_ops tcp_request_sock_ops __read_mostly = {
1691 .family = PF_INET,
1692 .obj_size = sizeof(struct tcp_request_sock),
1693 .rtx_syn_ack = tcp_rtx_synack,
1694 .send_ack = tcp_v4_reqsk_send_ack,
1695 .destructor = tcp_v4_reqsk_destructor,
1696 .send_reset = tcp_v4_send_reset,
1697 .syn_ack_timeout = tcp_syn_ack_timeout,
1698};
1699
1700const struct tcp_request_sock_ops tcp_request_sock_ipv4_ops = {
1701 .mss_clamp = TCP_MSS_DEFAULT,
1702#ifdef CONFIG_TCP_MD5SIG
1703 .req_md5_lookup = tcp_v4_md5_lookup,
1704 .calc_md5_hash = tcp_v4_md5_hash_skb,
1705#endif
1706#ifdef CONFIG_TCP_AO
1707 .ao_lookup = tcp_v4_ao_lookup_rsk,
1708 .ao_calc_key = tcp_v4_ao_calc_key_rsk,
1709 .ao_synack_hash = tcp_v4_ao_synack_hash,
1710#endif
1711#ifdef CONFIG_SYN_COOKIES
1712 .cookie_init_seq = cookie_v4_init_sequence,
1713#endif
1714 .route_req = tcp_v4_route_req,
1715 .init_seq = tcp_v4_init_seq,
1716 .init_ts_off = tcp_v4_init_ts_off,
1717 .send_synack = tcp_v4_send_synack,
1718};
1719
1720int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
1721{
1722 /* Never answer to SYNs send to broadcast or multicast */
1723 if (skb_rtable(skb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
1724 goto drop;
1725
1726 return tcp_conn_request(&tcp_request_sock_ops,
1727 &tcp_request_sock_ipv4_ops, sk, skb);
1728
1729drop:
1730 tcp_listendrop(sk);
1731 return 0;
1732}
1733EXPORT_SYMBOL(tcp_v4_conn_request);
1734
1735
1736/*
1737 * The three way handshake has completed - we got a valid synack -
1738 * now create the new socket.
1739 */
1740struct sock *tcp_v4_syn_recv_sock(const struct sock *sk, struct sk_buff *skb,
1741 struct request_sock *req,
1742 struct dst_entry *dst,
1743 struct request_sock *req_unhash,
1744 bool *own_req)
1745{
1746 struct inet_request_sock *ireq;
1747 bool found_dup_sk = false;
1748 struct inet_sock *newinet;
1749 struct tcp_sock *newtp;
1750 struct sock *newsk;
1751#ifdef CONFIG_TCP_MD5SIG
1752 const union tcp_md5_addr *addr;
1753 struct tcp_md5sig_key *key;
1754 int l3index;
1755#endif
1756 struct ip_options_rcu *inet_opt;
1757
1758 if (sk_acceptq_is_full(sk))
1759 goto exit_overflow;
1760
1761 newsk = tcp_create_openreq_child(sk, req, skb);
1762 if (!newsk)
1763 goto exit_nonewsk;
1764
1765 newsk->sk_gso_type = SKB_GSO_TCPV4;
1766 inet_sk_rx_dst_set(newsk, skb);
1767
1768 newtp = tcp_sk(newsk);
1769 newinet = inet_sk(newsk);
1770 ireq = inet_rsk(req);
1771 sk_daddr_set(newsk, ireq->ir_rmt_addr);
1772 sk_rcv_saddr_set(newsk, ireq->ir_loc_addr);
1773 newsk->sk_bound_dev_if = ireq->ir_iif;
1774 newinet->inet_saddr = ireq->ir_loc_addr;
1775 inet_opt = rcu_dereference(ireq->ireq_opt);
1776 RCU_INIT_POINTER(newinet->inet_opt, inet_opt);
1777 newinet->mc_index = inet_iif(skb);
1778 newinet->mc_ttl = ip_hdr(skb)->ttl;
1779 newinet->rcv_tos = ip_hdr(skb)->tos;
1780 inet_csk(newsk)->icsk_ext_hdr_len = 0;
1781 if (inet_opt)
1782 inet_csk(newsk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
1783 atomic_set(&newinet->inet_id, get_random_u16());
1784
1785 /* Set ToS of the new socket based upon the value of incoming SYN.
1786 * ECT bits are set later in tcp_init_transfer().
1787 */
1788 if (READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_reflect_tos))
1789 newinet->tos = tcp_rsk(req)->syn_tos & ~INET_ECN_MASK;
1790
1791 if (!dst) {
1792 dst = inet_csk_route_child_sock(sk, newsk, req);
1793 if (!dst)
1794 goto put_and_exit;
1795 } else {
1796 /* syncookie case : see end of cookie_v4_check() */
1797 }
1798 sk_setup_caps(newsk, dst);
1799
1800 tcp_ca_openreq_child(newsk, dst);
1801
1802 tcp_sync_mss(newsk, dst_mtu(dst));
1803 newtp->advmss = tcp_mss_clamp(tcp_sk(sk), dst_metric_advmss(dst));
1804
1805 tcp_initialize_rcv_mss(newsk);
1806
1807#ifdef CONFIG_TCP_MD5SIG
1808 l3index = l3mdev_master_ifindex_by_index(sock_net(sk), ireq->ir_iif);
1809 /* Copy over the MD5 key from the original socket */
1810 addr = (union tcp_md5_addr *)&newinet->inet_daddr;
1811 key = tcp_md5_do_lookup(sk, l3index, addr, AF_INET);
1812 if (key && !tcp_rsk_used_ao(req)) {
1813 if (tcp_md5_key_copy(newsk, addr, AF_INET, 32, l3index, key))
1814 goto put_and_exit;
1815 sk_gso_disable(newsk);
1816 }
1817#endif
1818#ifdef CONFIG_TCP_AO
1819 if (tcp_ao_copy_all_matching(sk, newsk, req, skb, AF_INET))
1820 goto put_and_exit; /* OOM, release back memory */
1821#endif
1822
1823 if (__inet_inherit_port(sk, newsk) < 0)
1824 goto put_and_exit;
1825 *own_req = inet_ehash_nolisten(newsk, req_to_sk(req_unhash),
1826 &found_dup_sk);
1827 if (likely(*own_req)) {
1828 tcp_move_syn(newtp, req);
1829 ireq->ireq_opt = NULL;
1830 } else {
1831 newinet->inet_opt = NULL;
1832
1833 if (!req_unhash && found_dup_sk) {
1834 /* This code path should only be executed in the
1835 * syncookie case only
1836 */
1837 bh_unlock_sock(newsk);
1838 sock_put(newsk);
1839 newsk = NULL;
1840 }
1841 }
1842 return newsk;
1843
1844exit_overflow:
1845 NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
1846exit_nonewsk:
1847 dst_release(dst);
1848exit:
1849 tcp_listendrop(sk);
1850 return NULL;
1851put_and_exit:
1852 newinet->inet_opt = NULL;
1853 inet_csk_prepare_forced_close(newsk);
1854 tcp_done(newsk);
1855 goto exit;
1856}
1857EXPORT_SYMBOL(tcp_v4_syn_recv_sock);
1858
1859static struct sock *tcp_v4_cookie_check(struct sock *sk, struct sk_buff *skb)
1860{
1861#ifdef CONFIG_SYN_COOKIES
1862 const struct tcphdr *th = tcp_hdr(skb);
1863
1864 if (!th->syn)
1865 sk = cookie_v4_check(sk, skb);
1866#endif
1867 return sk;
1868}
1869
1870u16 tcp_v4_get_syncookie(struct sock *sk, struct iphdr *iph,
1871 struct tcphdr *th, u32 *cookie)
1872{
1873 u16 mss = 0;
1874#ifdef CONFIG_SYN_COOKIES
1875 mss = tcp_get_syncookie_mss(&tcp_request_sock_ops,
1876 &tcp_request_sock_ipv4_ops, sk, th);
1877 if (mss) {
1878 *cookie = __cookie_v4_init_sequence(iph, th, &mss);
1879 tcp_synq_overflow(sk);
1880 }
1881#endif
1882 return mss;
1883}
1884
1885INDIRECT_CALLABLE_DECLARE(struct dst_entry *ipv4_dst_check(struct dst_entry *,
1886 u32));
1887/* The socket must have it's spinlock held when we get
1888 * here, unless it is a TCP_LISTEN socket.
1889 *
1890 * We have a potential double-lock case here, so even when
1891 * doing backlog processing we use the BH locking scheme.
1892 * This is because we cannot sleep with the original spinlock
1893 * held.
1894 */
1895int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
1896{
1897 enum skb_drop_reason reason;
1898 struct sock *rsk;
1899
1900 if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
1901 struct dst_entry *dst;
1902
1903 dst = rcu_dereference_protected(sk->sk_rx_dst,
1904 lockdep_sock_is_held(sk));
1905
1906 sock_rps_save_rxhash(sk, skb);
1907 sk_mark_napi_id(sk, skb);
1908 if (dst) {
1909 if (sk->sk_rx_dst_ifindex != skb->skb_iif ||
1910 !INDIRECT_CALL_1(dst->ops->check, ipv4_dst_check,
1911 dst, 0)) {
1912 RCU_INIT_POINTER(sk->sk_rx_dst, NULL);
1913 dst_release(dst);
1914 }
1915 }
1916 tcp_rcv_established(sk, skb);
1917 return 0;
1918 }
1919
1920 if (tcp_checksum_complete(skb))
1921 goto csum_err;
1922
1923 if (sk->sk_state == TCP_LISTEN) {
1924 struct sock *nsk = tcp_v4_cookie_check(sk, skb);
1925
1926 if (!nsk)
1927 return 0;
1928 if (nsk != sk) {
1929 reason = tcp_child_process(sk, nsk, skb);
1930 if (reason) {
1931 rsk = nsk;
1932 goto reset;
1933 }
1934 return 0;
1935 }
1936 } else
1937 sock_rps_save_rxhash(sk, skb);
1938
1939 reason = tcp_rcv_state_process(sk, skb);
1940 if (reason) {
1941 rsk = sk;
1942 goto reset;
1943 }
1944 return 0;
1945
1946reset:
1947 tcp_v4_send_reset(rsk, skb, sk_rst_convert_drop_reason(reason));
1948discard:
1949 sk_skb_reason_drop(sk, skb, reason);
1950 /* Be careful here. If this function gets more complicated and
1951 * gcc suffers from register pressure on the x86, sk (in %ebx)
1952 * might be destroyed here. This current version compiles correctly,
1953 * but you have been warned.
1954 */
1955 return 0;
1956
1957csum_err:
1958 reason = SKB_DROP_REASON_TCP_CSUM;
1959 trace_tcp_bad_csum(skb);
1960 TCP_INC_STATS(sock_net(sk), TCP_MIB_CSUMERRORS);
1961 TCP_INC_STATS(sock_net(sk), TCP_MIB_INERRS);
1962 goto discard;
1963}
1964EXPORT_SYMBOL(tcp_v4_do_rcv);
1965
1966int tcp_v4_early_demux(struct sk_buff *skb)
1967{
1968 struct net *net = dev_net(skb->dev);
1969 const struct iphdr *iph;
1970 const struct tcphdr *th;
1971 struct sock *sk;
1972
1973 if (skb->pkt_type != PACKET_HOST)
1974 return 0;
1975
1976 if (!pskb_may_pull(skb, skb_transport_offset(skb) + sizeof(struct tcphdr)))
1977 return 0;
1978
1979 iph = ip_hdr(skb);
1980 th = tcp_hdr(skb);
1981
1982 if (th->doff < sizeof(struct tcphdr) / 4)
1983 return 0;
1984
1985 sk = __inet_lookup_established(net, net->ipv4.tcp_death_row.hashinfo,
1986 iph->saddr, th->source,
1987 iph->daddr, ntohs(th->dest),
1988 skb->skb_iif, inet_sdif(skb));
1989 if (sk) {
1990 skb->sk = sk;
1991 skb->destructor = sock_edemux;
1992 if (sk_fullsock(sk)) {
1993 struct dst_entry *dst = rcu_dereference(sk->sk_rx_dst);
1994
1995 if (dst)
1996 dst = dst_check(dst, 0);
1997 if (dst &&
1998 sk->sk_rx_dst_ifindex == skb->skb_iif)
1999 skb_dst_set_noref(skb, dst);
2000 }
2001 }
2002 return 0;
2003}
2004
2005bool tcp_add_backlog(struct sock *sk, struct sk_buff *skb,
2006 enum skb_drop_reason *reason)
2007{
2008 u32 tail_gso_size, tail_gso_segs;
2009 struct skb_shared_info *shinfo;
2010 const struct tcphdr *th;
2011 struct tcphdr *thtail;
2012 struct sk_buff *tail;
2013 unsigned int hdrlen;
2014 bool fragstolen;
2015 u32 gso_segs;
2016 u32 gso_size;
2017 u64 limit;
2018 int delta;
2019
2020 /* In case all data was pulled from skb frags (in __pskb_pull_tail()),
2021 * we can fix skb->truesize to its real value to avoid future drops.
2022 * This is valid because skb is not yet charged to the socket.
2023 * It has been noticed pure SACK packets were sometimes dropped
2024 * (if cooked by drivers without copybreak feature).
2025 */
2026 skb_condense(skb);
2027
2028 tcp_cleanup_skb(skb);
2029
2030 if (unlikely(tcp_checksum_complete(skb))) {
2031 bh_unlock_sock(sk);
2032 trace_tcp_bad_csum(skb);
2033 *reason = SKB_DROP_REASON_TCP_CSUM;
2034 __TCP_INC_STATS(sock_net(sk), TCP_MIB_CSUMERRORS);
2035 __TCP_INC_STATS(sock_net(sk), TCP_MIB_INERRS);
2036 return true;
2037 }
2038
2039 /* Attempt coalescing to last skb in backlog, even if we are
2040 * above the limits.
2041 * This is okay because skb capacity is limited to MAX_SKB_FRAGS.
2042 */
2043 th = (const struct tcphdr *)skb->data;
2044 hdrlen = th->doff * 4;
2045
2046 tail = sk->sk_backlog.tail;
2047 if (!tail)
2048 goto no_coalesce;
2049 thtail = (struct tcphdr *)tail->data;
2050
2051 if (TCP_SKB_CB(tail)->end_seq != TCP_SKB_CB(skb)->seq ||
2052 TCP_SKB_CB(tail)->ip_dsfield != TCP_SKB_CB(skb)->ip_dsfield ||
2053 ((TCP_SKB_CB(tail)->tcp_flags |
2054 TCP_SKB_CB(skb)->tcp_flags) & (TCPHDR_SYN | TCPHDR_RST | TCPHDR_URG)) ||
2055 !((TCP_SKB_CB(tail)->tcp_flags &
2056 TCP_SKB_CB(skb)->tcp_flags) & TCPHDR_ACK) ||
2057 ((TCP_SKB_CB(tail)->tcp_flags ^
2058 TCP_SKB_CB(skb)->tcp_flags) & (TCPHDR_ECE | TCPHDR_CWR)) ||
2059 !tcp_skb_can_collapse_rx(tail, skb) ||
2060 thtail->doff != th->doff ||
2061 memcmp(thtail + 1, th + 1, hdrlen - sizeof(*th)))
2062 goto no_coalesce;
2063
2064 __skb_pull(skb, hdrlen);
2065
2066 shinfo = skb_shinfo(skb);
2067 gso_size = shinfo->gso_size ?: skb->len;
2068 gso_segs = shinfo->gso_segs ?: 1;
2069
2070 shinfo = skb_shinfo(tail);
2071 tail_gso_size = shinfo->gso_size ?: (tail->len - hdrlen);
2072 tail_gso_segs = shinfo->gso_segs ?: 1;
2073
2074 if (skb_try_coalesce(tail, skb, &fragstolen, &delta)) {
2075 TCP_SKB_CB(tail)->end_seq = TCP_SKB_CB(skb)->end_seq;
2076
2077 if (likely(!before(TCP_SKB_CB(skb)->ack_seq, TCP_SKB_CB(tail)->ack_seq))) {
2078 TCP_SKB_CB(tail)->ack_seq = TCP_SKB_CB(skb)->ack_seq;
2079 thtail->window = th->window;
2080 }
2081
2082 /* We have to update both TCP_SKB_CB(tail)->tcp_flags and
2083 * thtail->fin, so that the fast path in tcp_rcv_established()
2084 * is not entered if we append a packet with a FIN.
2085 * SYN, RST, URG are not present.
2086 * ACK is set on both packets.
2087 * PSH : we do not really care in TCP stack,
2088 * at least for 'GRO' packets.
2089 */
2090 thtail->fin |= th->fin;
2091 TCP_SKB_CB(tail)->tcp_flags |= TCP_SKB_CB(skb)->tcp_flags;
2092
2093 if (TCP_SKB_CB(skb)->has_rxtstamp) {
2094 TCP_SKB_CB(tail)->has_rxtstamp = true;
2095 tail->tstamp = skb->tstamp;
2096 skb_hwtstamps(tail)->hwtstamp = skb_hwtstamps(skb)->hwtstamp;
2097 }
2098
2099 /* Not as strict as GRO. We only need to carry mss max value */
2100 shinfo->gso_size = max(gso_size, tail_gso_size);
2101 shinfo->gso_segs = min_t(u32, gso_segs + tail_gso_segs, 0xFFFF);
2102
2103 sk->sk_backlog.len += delta;
2104 __NET_INC_STATS(sock_net(sk),
2105 LINUX_MIB_TCPBACKLOGCOALESCE);
2106 kfree_skb_partial(skb, fragstolen);
2107 return false;
2108 }
2109 __skb_push(skb, hdrlen);
2110
2111no_coalesce:
2112 /* sk->sk_backlog.len is reset only at the end of __release_sock().
2113 * Both sk->sk_backlog.len and sk->sk_rmem_alloc could reach
2114 * sk_rcvbuf in normal conditions.
2115 */
2116 limit = ((u64)READ_ONCE(sk->sk_rcvbuf)) << 1;
2117
2118 limit += ((u32)READ_ONCE(sk->sk_sndbuf)) >> 1;
2119
2120 /* Only socket owner can try to collapse/prune rx queues
2121 * to reduce memory overhead, so add a little headroom here.
2122 * Few sockets backlog are possibly concurrently non empty.
2123 */
2124 limit += 64 * 1024;
2125
2126 limit = min_t(u64, limit, UINT_MAX);
2127
2128 if (unlikely(sk_add_backlog(sk, skb, limit))) {
2129 bh_unlock_sock(sk);
2130 *reason = SKB_DROP_REASON_SOCKET_BACKLOG;
2131 __NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPBACKLOGDROP);
2132 return true;
2133 }
2134 return false;
2135}
2136EXPORT_SYMBOL(tcp_add_backlog);
2137
2138int tcp_filter(struct sock *sk, struct sk_buff *skb)
2139{
2140 struct tcphdr *th = (struct tcphdr *)skb->data;
2141
2142 return sk_filter_trim_cap(sk, skb, th->doff * 4);
2143}
2144EXPORT_SYMBOL(tcp_filter);
2145
2146static void tcp_v4_restore_cb(struct sk_buff *skb)
2147{
2148 memmove(IPCB(skb), &TCP_SKB_CB(skb)->header.h4,
2149 sizeof(struct inet_skb_parm));
2150}
2151
2152static void tcp_v4_fill_cb(struct sk_buff *skb, const struct iphdr *iph,
2153 const struct tcphdr *th)
2154{
2155 /* This is tricky : We move IPCB at its correct location into TCP_SKB_CB()
2156 * barrier() makes sure compiler wont play fool^Waliasing games.
2157 */
2158 memmove(&TCP_SKB_CB(skb)->header.h4, IPCB(skb),
2159 sizeof(struct inet_skb_parm));
2160 barrier();
2161
2162 TCP_SKB_CB(skb)->seq = ntohl(th->seq);
2163 TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
2164 skb->len - th->doff * 4);
2165 TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
2166 TCP_SKB_CB(skb)->tcp_flags = tcp_flag_byte(th);
2167 TCP_SKB_CB(skb)->ip_dsfield = ipv4_get_dsfield(iph);
2168 TCP_SKB_CB(skb)->sacked = 0;
2169 TCP_SKB_CB(skb)->has_rxtstamp =
2170 skb->tstamp || skb_hwtstamps(skb)->hwtstamp;
2171}
2172
2173/*
2174 * From tcp_input.c
2175 */
2176
2177int tcp_v4_rcv(struct sk_buff *skb)
2178{
2179 struct net *net = dev_net(skb->dev);
2180 enum skb_drop_reason drop_reason;
2181 int sdif = inet_sdif(skb);
2182 int dif = inet_iif(skb);
2183 const struct iphdr *iph;
2184 const struct tcphdr *th;
2185 struct sock *sk = NULL;
2186 bool refcounted;
2187 int ret;
2188 u32 isn;
2189
2190 drop_reason = SKB_DROP_REASON_NOT_SPECIFIED;
2191 if (skb->pkt_type != PACKET_HOST)
2192 goto discard_it;
2193
2194 /* Count it even if it's bad */
2195 __TCP_INC_STATS(net, TCP_MIB_INSEGS);
2196
2197 if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
2198 goto discard_it;
2199
2200 th = (const struct tcphdr *)skb->data;
2201
2202 if (unlikely(th->doff < sizeof(struct tcphdr) / 4)) {
2203 drop_reason = SKB_DROP_REASON_PKT_TOO_SMALL;
2204 goto bad_packet;
2205 }
2206 if (!pskb_may_pull(skb, th->doff * 4))
2207 goto discard_it;
2208
2209 /* An explanation is required here, I think.
2210 * Packet length and doff are validated by header prediction,
2211 * provided case of th->doff==0 is eliminated.
2212 * So, we defer the checks. */
2213
2214 if (skb_checksum_init(skb, IPPROTO_TCP, inet_compute_pseudo))
2215 goto csum_error;
2216
2217 th = (const struct tcphdr *)skb->data;
2218 iph = ip_hdr(skb);
2219lookup:
2220 sk = __inet_lookup_skb(net->ipv4.tcp_death_row.hashinfo,
2221 skb, __tcp_hdrlen(th), th->source,
2222 th->dest, sdif, &refcounted);
2223 if (!sk)
2224 goto no_tcp_socket;
2225
2226 if (sk->sk_state == TCP_TIME_WAIT)
2227 goto do_time_wait;
2228
2229 if (sk->sk_state == TCP_NEW_SYN_RECV) {
2230 struct request_sock *req = inet_reqsk(sk);
2231 bool req_stolen = false;
2232 struct sock *nsk;
2233
2234 sk = req->rsk_listener;
2235 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
2236 drop_reason = SKB_DROP_REASON_XFRM_POLICY;
2237 else
2238 drop_reason = tcp_inbound_hash(sk, req, skb,
2239 &iph->saddr, &iph->daddr,
2240 AF_INET, dif, sdif);
2241 if (unlikely(drop_reason)) {
2242 sk_drops_add(sk, skb);
2243 reqsk_put(req);
2244 goto discard_it;
2245 }
2246 if (tcp_checksum_complete(skb)) {
2247 reqsk_put(req);
2248 goto csum_error;
2249 }
2250 if (unlikely(sk->sk_state != TCP_LISTEN)) {
2251 nsk = reuseport_migrate_sock(sk, req_to_sk(req), skb);
2252 if (!nsk) {
2253 inet_csk_reqsk_queue_drop_and_put(sk, req);
2254 goto lookup;
2255 }
2256 sk = nsk;
2257 /* reuseport_migrate_sock() has already held one sk_refcnt
2258 * before returning.
2259 */
2260 } else {
2261 /* We own a reference on the listener, increase it again
2262 * as we might lose it too soon.
2263 */
2264 sock_hold(sk);
2265 }
2266 refcounted = true;
2267 nsk = NULL;
2268 if (!tcp_filter(sk, skb)) {
2269 th = (const struct tcphdr *)skb->data;
2270 iph = ip_hdr(skb);
2271 tcp_v4_fill_cb(skb, iph, th);
2272 nsk = tcp_check_req(sk, skb, req, false, &req_stolen);
2273 } else {
2274 drop_reason = SKB_DROP_REASON_SOCKET_FILTER;
2275 }
2276 if (!nsk) {
2277 reqsk_put(req);
2278 if (req_stolen) {
2279 /* Another cpu got exclusive access to req
2280 * and created a full blown socket.
2281 * Try to feed this packet to this socket
2282 * instead of discarding it.
2283 */
2284 tcp_v4_restore_cb(skb);
2285 sock_put(sk);
2286 goto lookup;
2287 }
2288 goto discard_and_relse;
2289 }
2290 nf_reset_ct(skb);
2291 if (nsk == sk) {
2292 reqsk_put(req);
2293 tcp_v4_restore_cb(skb);
2294 } else {
2295 drop_reason = tcp_child_process(sk, nsk, skb);
2296 if (drop_reason) {
2297 enum sk_rst_reason rst_reason;
2298
2299 rst_reason = sk_rst_convert_drop_reason(drop_reason);
2300 tcp_v4_send_reset(nsk, skb, rst_reason);
2301 goto discard_and_relse;
2302 }
2303 sock_put(sk);
2304 return 0;
2305 }
2306 }
2307
2308process:
2309 if (static_branch_unlikely(&ip4_min_ttl)) {
2310 /* min_ttl can be changed concurrently from do_ip_setsockopt() */
2311 if (unlikely(iph->ttl < READ_ONCE(inet_sk(sk)->min_ttl))) {
2312 __NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP);
2313 drop_reason = SKB_DROP_REASON_TCP_MINTTL;
2314 goto discard_and_relse;
2315 }
2316 }
2317
2318 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb)) {
2319 drop_reason = SKB_DROP_REASON_XFRM_POLICY;
2320 goto discard_and_relse;
2321 }
2322
2323 drop_reason = tcp_inbound_hash(sk, NULL, skb, &iph->saddr, &iph->daddr,
2324 AF_INET, dif, sdif);
2325 if (drop_reason)
2326 goto discard_and_relse;
2327
2328 nf_reset_ct(skb);
2329
2330 if (tcp_filter(sk, skb)) {
2331 drop_reason = SKB_DROP_REASON_SOCKET_FILTER;
2332 goto discard_and_relse;
2333 }
2334 th = (const struct tcphdr *)skb->data;
2335 iph = ip_hdr(skb);
2336 tcp_v4_fill_cb(skb, iph, th);
2337
2338 skb->dev = NULL;
2339
2340 if (sk->sk_state == TCP_LISTEN) {
2341 ret = tcp_v4_do_rcv(sk, skb);
2342 goto put_and_return;
2343 }
2344
2345 sk_incoming_cpu_update(sk);
2346
2347 bh_lock_sock_nested(sk);
2348 tcp_segs_in(tcp_sk(sk), skb);
2349 ret = 0;
2350 if (!sock_owned_by_user(sk)) {
2351 ret = tcp_v4_do_rcv(sk, skb);
2352 } else {
2353 if (tcp_add_backlog(sk, skb, &drop_reason))
2354 goto discard_and_relse;
2355 }
2356 bh_unlock_sock(sk);
2357
2358put_and_return:
2359 if (refcounted)
2360 sock_put(sk);
2361
2362 return ret;
2363
2364no_tcp_socket:
2365 drop_reason = SKB_DROP_REASON_NO_SOCKET;
2366 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
2367 goto discard_it;
2368
2369 tcp_v4_fill_cb(skb, iph, th);
2370
2371 if (tcp_checksum_complete(skb)) {
2372csum_error:
2373 drop_reason = SKB_DROP_REASON_TCP_CSUM;
2374 trace_tcp_bad_csum(skb);
2375 __TCP_INC_STATS(net, TCP_MIB_CSUMERRORS);
2376bad_packet:
2377 __TCP_INC_STATS(net, TCP_MIB_INERRS);
2378 } else {
2379 tcp_v4_send_reset(NULL, skb, sk_rst_convert_drop_reason(drop_reason));
2380 }
2381
2382discard_it:
2383 SKB_DR_OR(drop_reason, NOT_SPECIFIED);
2384 /* Discard frame. */
2385 sk_skb_reason_drop(sk, skb, drop_reason);
2386 return 0;
2387
2388discard_and_relse:
2389 sk_drops_add(sk, skb);
2390 if (refcounted)
2391 sock_put(sk);
2392 goto discard_it;
2393
2394do_time_wait:
2395 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
2396 drop_reason = SKB_DROP_REASON_XFRM_POLICY;
2397 inet_twsk_put(inet_twsk(sk));
2398 goto discard_it;
2399 }
2400
2401 tcp_v4_fill_cb(skb, iph, th);
2402
2403 if (tcp_checksum_complete(skb)) {
2404 inet_twsk_put(inet_twsk(sk));
2405 goto csum_error;
2406 }
2407 switch (tcp_timewait_state_process(inet_twsk(sk), skb, th, &isn)) {
2408 case TCP_TW_SYN: {
2409 struct sock *sk2 = inet_lookup_listener(net,
2410 net->ipv4.tcp_death_row.hashinfo,
2411 skb, __tcp_hdrlen(th),
2412 iph->saddr, th->source,
2413 iph->daddr, th->dest,
2414 inet_iif(skb),
2415 sdif);
2416 if (sk2) {
2417 inet_twsk_deschedule_put(inet_twsk(sk));
2418 sk = sk2;
2419 tcp_v4_restore_cb(skb);
2420 refcounted = false;
2421 __this_cpu_write(tcp_tw_isn, isn);
2422 goto process;
2423 }
2424 }
2425 /* to ACK */
2426 fallthrough;
2427 case TCP_TW_ACK:
2428 tcp_v4_timewait_ack(sk, skb);
2429 break;
2430 case TCP_TW_RST:
2431 tcp_v4_send_reset(sk, skb, SK_RST_REASON_TCP_TIMEWAIT_SOCKET);
2432 inet_twsk_deschedule_put(inet_twsk(sk));
2433 goto discard_it;
2434 case TCP_TW_SUCCESS:;
2435 }
2436 goto discard_it;
2437}
2438
2439static struct timewait_sock_ops tcp_timewait_sock_ops = {
2440 .twsk_obj_size = sizeof(struct tcp_timewait_sock),
2441 .twsk_destructor= tcp_twsk_destructor,
2442};
2443
2444void inet_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb)
2445{
2446 struct dst_entry *dst = skb_dst(skb);
2447
2448 if (dst && dst_hold_safe(dst)) {
2449 rcu_assign_pointer(sk->sk_rx_dst, dst);
2450 sk->sk_rx_dst_ifindex = skb->skb_iif;
2451 }
2452}
2453EXPORT_SYMBOL(inet_sk_rx_dst_set);
2454
2455const struct inet_connection_sock_af_ops ipv4_specific = {
2456 .queue_xmit = ip_queue_xmit,
2457 .send_check = tcp_v4_send_check,
2458 .rebuild_header = inet_sk_rebuild_header,
2459 .sk_rx_dst_set = inet_sk_rx_dst_set,
2460 .conn_request = tcp_v4_conn_request,
2461 .syn_recv_sock = tcp_v4_syn_recv_sock,
2462 .net_header_len = sizeof(struct iphdr),
2463 .setsockopt = ip_setsockopt,
2464 .getsockopt = ip_getsockopt,
2465 .addr2sockaddr = inet_csk_addr2sockaddr,
2466 .sockaddr_len = sizeof(struct sockaddr_in),
2467 .mtu_reduced = tcp_v4_mtu_reduced,
2468};
2469EXPORT_SYMBOL(ipv4_specific);
2470
2471#if defined(CONFIG_TCP_MD5SIG) || defined(CONFIG_TCP_AO)
2472static const struct tcp_sock_af_ops tcp_sock_ipv4_specific = {
2473#ifdef CONFIG_TCP_MD5SIG
2474 .md5_lookup = tcp_v4_md5_lookup,
2475 .calc_md5_hash = tcp_v4_md5_hash_skb,
2476 .md5_parse = tcp_v4_parse_md5_keys,
2477#endif
2478#ifdef CONFIG_TCP_AO
2479 .ao_lookup = tcp_v4_ao_lookup,
2480 .calc_ao_hash = tcp_v4_ao_hash_skb,
2481 .ao_parse = tcp_v4_parse_ao,
2482 .ao_calc_key_sk = tcp_v4_ao_calc_key_sk,
2483#endif
2484};
2485#endif
2486
2487/* NOTE: A lot of things set to zero explicitly by call to
2488 * sk_alloc() so need not be done here.
2489 */
2490static int tcp_v4_init_sock(struct sock *sk)
2491{
2492 struct inet_connection_sock *icsk = inet_csk(sk);
2493
2494 tcp_init_sock(sk);
2495
2496 icsk->icsk_af_ops = &ipv4_specific;
2497
2498#if defined(CONFIG_TCP_MD5SIG) || defined(CONFIG_TCP_AO)
2499 tcp_sk(sk)->af_specific = &tcp_sock_ipv4_specific;
2500#endif
2501
2502 return 0;
2503}
2504
2505#ifdef CONFIG_TCP_MD5SIG
2506static void tcp_md5sig_info_free_rcu(struct rcu_head *head)
2507{
2508 struct tcp_md5sig_info *md5sig;
2509
2510 md5sig = container_of(head, struct tcp_md5sig_info, rcu);
2511 kfree(md5sig);
2512 static_branch_slow_dec_deferred(&tcp_md5_needed);
2513 tcp_md5_release_sigpool();
2514}
2515#endif
2516
2517static void tcp_release_user_frags(struct sock *sk)
2518{
2519#ifdef CONFIG_PAGE_POOL
2520 unsigned long index;
2521 void *netmem;
2522
2523 xa_for_each(&sk->sk_user_frags, index, netmem)
2524 WARN_ON_ONCE(!napi_pp_put_page((__force netmem_ref)netmem));
2525#endif
2526}
2527
2528void tcp_v4_destroy_sock(struct sock *sk)
2529{
2530 struct tcp_sock *tp = tcp_sk(sk);
2531
2532 tcp_release_user_frags(sk);
2533
2534 xa_destroy(&sk->sk_user_frags);
2535
2536 trace_tcp_destroy_sock(sk);
2537
2538 tcp_clear_xmit_timers(sk);
2539
2540 tcp_cleanup_congestion_control(sk);
2541
2542 tcp_cleanup_ulp(sk);
2543
2544 /* Cleanup up the write buffer. */
2545 tcp_write_queue_purge(sk);
2546
2547 /* Check if we want to disable active TFO */
2548 tcp_fastopen_active_disable_ofo_check(sk);
2549
2550 /* Cleans up our, hopefully empty, out_of_order_queue. */
2551 skb_rbtree_purge(&tp->out_of_order_queue);
2552
2553#ifdef CONFIG_TCP_MD5SIG
2554 /* Clean up the MD5 key list, if any */
2555 if (tp->md5sig_info) {
2556 struct tcp_md5sig_info *md5sig;
2557
2558 md5sig = rcu_dereference_protected(tp->md5sig_info, 1);
2559 tcp_clear_md5_list(sk);
2560 call_rcu(&md5sig->rcu, tcp_md5sig_info_free_rcu);
2561 rcu_assign_pointer(tp->md5sig_info, NULL);
2562 }
2563#endif
2564 tcp_ao_destroy_sock(sk, false);
2565
2566 /* Clean up a referenced TCP bind bucket. */
2567 if (inet_csk(sk)->icsk_bind_hash)
2568 inet_put_port(sk);
2569
2570 BUG_ON(rcu_access_pointer(tp->fastopen_rsk));
2571
2572 /* If socket is aborted during connect operation */
2573 tcp_free_fastopen_req(tp);
2574 tcp_fastopen_destroy_cipher(sk);
2575 tcp_saved_syn_free(tp);
2576
2577 sk_sockets_allocated_dec(sk);
2578}
2579EXPORT_SYMBOL(tcp_v4_destroy_sock);
2580
2581#ifdef CONFIG_PROC_FS
2582/* Proc filesystem TCP sock list dumping. */
2583
2584static unsigned short seq_file_family(const struct seq_file *seq);
2585
2586static bool seq_sk_match(struct seq_file *seq, const struct sock *sk)
2587{
2588 unsigned short family = seq_file_family(seq);
2589
2590 /* AF_UNSPEC is used as a match all */
2591 return ((family == AF_UNSPEC || family == sk->sk_family) &&
2592 net_eq(sock_net(sk), seq_file_net(seq)));
2593}
2594
2595/* Find a non empty bucket (starting from st->bucket)
2596 * and return the first sk from it.
2597 */
2598static void *listening_get_first(struct seq_file *seq)
2599{
2600 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo;
2601 struct tcp_iter_state *st = seq->private;
2602
2603 st->offset = 0;
2604 for (; st->bucket <= hinfo->lhash2_mask; st->bucket++) {
2605 struct inet_listen_hashbucket *ilb2;
2606 struct hlist_nulls_node *node;
2607 struct sock *sk;
2608
2609 ilb2 = &hinfo->lhash2[st->bucket];
2610 if (hlist_nulls_empty(&ilb2->nulls_head))
2611 continue;
2612
2613 spin_lock(&ilb2->lock);
2614 sk_nulls_for_each(sk, node, &ilb2->nulls_head) {
2615 if (seq_sk_match(seq, sk))
2616 return sk;
2617 }
2618 spin_unlock(&ilb2->lock);
2619 }
2620
2621 return NULL;
2622}
2623
2624/* Find the next sk of "cur" within the same bucket (i.e. st->bucket).
2625 * If "cur" is the last one in the st->bucket,
2626 * call listening_get_first() to return the first sk of the next
2627 * non empty bucket.
2628 */
2629static void *listening_get_next(struct seq_file *seq, void *cur)
2630{
2631 struct tcp_iter_state *st = seq->private;
2632 struct inet_listen_hashbucket *ilb2;
2633 struct hlist_nulls_node *node;
2634 struct inet_hashinfo *hinfo;
2635 struct sock *sk = cur;
2636
2637 ++st->num;
2638 ++st->offset;
2639
2640 sk = sk_nulls_next(sk);
2641 sk_nulls_for_each_from(sk, node) {
2642 if (seq_sk_match(seq, sk))
2643 return sk;
2644 }
2645
2646 hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo;
2647 ilb2 = &hinfo->lhash2[st->bucket];
2648 spin_unlock(&ilb2->lock);
2649 ++st->bucket;
2650 return listening_get_first(seq);
2651}
2652
2653static void *listening_get_idx(struct seq_file *seq, loff_t *pos)
2654{
2655 struct tcp_iter_state *st = seq->private;
2656 void *rc;
2657
2658 st->bucket = 0;
2659 st->offset = 0;
2660 rc = listening_get_first(seq);
2661
2662 while (rc && *pos) {
2663 rc = listening_get_next(seq, rc);
2664 --*pos;
2665 }
2666 return rc;
2667}
2668
2669static inline bool empty_bucket(struct inet_hashinfo *hinfo,
2670 const struct tcp_iter_state *st)
2671{
2672 return hlist_nulls_empty(&hinfo->ehash[st->bucket].chain);
2673}
2674
2675/*
2676 * Get first established socket starting from bucket given in st->bucket.
2677 * If st->bucket is zero, the very first socket in the hash is returned.
2678 */
2679static void *established_get_first(struct seq_file *seq)
2680{
2681 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo;
2682 struct tcp_iter_state *st = seq->private;
2683
2684 st->offset = 0;
2685 for (; st->bucket <= hinfo->ehash_mask; ++st->bucket) {
2686 struct sock *sk;
2687 struct hlist_nulls_node *node;
2688 spinlock_t *lock = inet_ehash_lockp(hinfo, st->bucket);
2689
2690 cond_resched();
2691
2692 /* Lockless fast path for the common case of empty buckets */
2693 if (empty_bucket(hinfo, st))
2694 continue;
2695
2696 spin_lock_bh(lock);
2697 sk_nulls_for_each(sk, node, &hinfo->ehash[st->bucket].chain) {
2698 if (seq_sk_match(seq, sk))
2699 return sk;
2700 }
2701 spin_unlock_bh(lock);
2702 }
2703
2704 return NULL;
2705}
2706
2707static void *established_get_next(struct seq_file *seq, void *cur)
2708{
2709 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo;
2710 struct tcp_iter_state *st = seq->private;
2711 struct hlist_nulls_node *node;
2712 struct sock *sk = cur;
2713
2714 ++st->num;
2715 ++st->offset;
2716
2717 sk = sk_nulls_next(sk);
2718
2719 sk_nulls_for_each_from(sk, node) {
2720 if (seq_sk_match(seq, sk))
2721 return sk;
2722 }
2723
2724 spin_unlock_bh(inet_ehash_lockp(hinfo, st->bucket));
2725 ++st->bucket;
2726 return established_get_first(seq);
2727}
2728
2729static void *established_get_idx(struct seq_file *seq, loff_t pos)
2730{
2731 struct tcp_iter_state *st = seq->private;
2732 void *rc;
2733
2734 st->bucket = 0;
2735 rc = established_get_first(seq);
2736
2737 while (rc && pos) {
2738 rc = established_get_next(seq, rc);
2739 --pos;
2740 }
2741 return rc;
2742}
2743
2744static void *tcp_get_idx(struct seq_file *seq, loff_t pos)
2745{
2746 void *rc;
2747 struct tcp_iter_state *st = seq->private;
2748
2749 st->state = TCP_SEQ_STATE_LISTENING;
2750 rc = listening_get_idx(seq, &pos);
2751
2752 if (!rc) {
2753 st->state = TCP_SEQ_STATE_ESTABLISHED;
2754 rc = established_get_idx(seq, pos);
2755 }
2756
2757 return rc;
2758}
2759
2760static void *tcp_seek_last_pos(struct seq_file *seq)
2761{
2762 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo;
2763 struct tcp_iter_state *st = seq->private;
2764 int bucket = st->bucket;
2765 int offset = st->offset;
2766 int orig_num = st->num;
2767 void *rc = NULL;
2768
2769 switch (st->state) {
2770 case TCP_SEQ_STATE_LISTENING:
2771 if (st->bucket > hinfo->lhash2_mask)
2772 break;
2773 rc = listening_get_first(seq);
2774 while (offset-- && rc && bucket == st->bucket)
2775 rc = listening_get_next(seq, rc);
2776 if (rc)
2777 break;
2778 st->bucket = 0;
2779 st->state = TCP_SEQ_STATE_ESTABLISHED;
2780 fallthrough;
2781 case TCP_SEQ_STATE_ESTABLISHED:
2782 if (st->bucket > hinfo->ehash_mask)
2783 break;
2784 rc = established_get_first(seq);
2785 while (offset-- && rc && bucket == st->bucket)
2786 rc = established_get_next(seq, rc);
2787 }
2788
2789 st->num = orig_num;
2790
2791 return rc;
2792}
2793
2794void *tcp_seq_start(struct seq_file *seq, loff_t *pos)
2795{
2796 struct tcp_iter_state *st = seq->private;
2797 void *rc;
2798
2799 if (*pos && *pos == st->last_pos) {
2800 rc = tcp_seek_last_pos(seq);
2801 if (rc)
2802 goto out;
2803 }
2804
2805 st->state = TCP_SEQ_STATE_LISTENING;
2806 st->num = 0;
2807 st->bucket = 0;
2808 st->offset = 0;
2809 rc = *pos ? tcp_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
2810
2811out:
2812 st->last_pos = *pos;
2813 return rc;
2814}
2815EXPORT_SYMBOL(tcp_seq_start);
2816
2817void *tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2818{
2819 struct tcp_iter_state *st = seq->private;
2820 void *rc = NULL;
2821
2822 if (v == SEQ_START_TOKEN) {
2823 rc = tcp_get_idx(seq, 0);
2824 goto out;
2825 }
2826
2827 switch (st->state) {
2828 case TCP_SEQ_STATE_LISTENING:
2829 rc = listening_get_next(seq, v);
2830 if (!rc) {
2831 st->state = TCP_SEQ_STATE_ESTABLISHED;
2832 st->bucket = 0;
2833 st->offset = 0;
2834 rc = established_get_first(seq);
2835 }
2836 break;
2837 case TCP_SEQ_STATE_ESTABLISHED:
2838 rc = established_get_next(seq, v);
2839 break;
2840 }
2841out:
2842 ++*pos;
2843 st->last_pos = *pos;
2844 return rc;
2845}
2846EXPORT_SYMBOL(tcp_seq_next);
2847
2848void tcp_seq_stop(struct seq_file *seq, void *v)
2849{
2850 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo;
2851 struct tcp_iter_state *st = seq->private;
2852
2853 switch (st->state) {
2854 case TCP_SEQ_STATE_LISTENING:
2855 if (v != SEQ_START_TOKEN)
2856 spin_unlock(&hinfo->lhash2[st->bucket].lock);
2857 break;
2858 case TCP_SEQ_STATE_ESTABLISHED:
2859 if (v)
2860 spin_unlock_bh(inet_ehash_lockp(hinfo, st->bucket));
2861 break;
2862 }
2863}
2864EXPORT_SYMBOL(tcp_seq_stop);
2865
2866static void get_openreq4(const struct request_sock *req,
2867 struct seq_file *f, int i)
2868{
2869 const struct inet_request_sock *ireq = inet_rsk(req);
2870 long delta = req->rsk_timer.expires - jiffies;
2871
2872 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2873 " %02X %08X:%08X %02X:%08lX %08X %5u %8d %u %d %pK",
2874 i,
2875 ireq->ir_loc_addr,
2876 ireq->ir_num,
2877 ireq->ir_rmt_addr,
2878 ntohs(ireq->ir_rmt_port),
2879 TCP_SYN_RECV,
2880 0, 0, /* could print option size, but that is af dependent. */
2881 1, /* timers active (only the expire timer) */
2882 jiffies_delta_to_clock_t(delta),
2883 req->num_timeout,
2884 from_kuid_munged(seq_user_ns(f),
2885 sock_i_uid(req->rsk_listener)),
2886 0, /* non standard timer */
2887 0, /* open_requests have no inode */
2888 0,
2889 req);
2890}
2891
2892static void get_tcp4_sock(struct sock *sk, struct seq_file *f, int i)
2893{
2894 int timer_active;
2895 unsigned long timer_expires;
2896 const struct tcp_sock *tp = tcp_sk(sk);
2897 const struct inet_connection_sock *icsk = inet_csk(sk);
2898 const struct inet_sock *inet = inet_sk(sk);
2899 const struct fastopen_queue *fastopenq = &icsk->icsk_accept_queue.fastopenq;
2900 __be32 dest = inet->inet_daddr;
2901 __be32 src = inet->inet_rcv_saddr;
2902 __u16 destp = ntohs(inet->inet_dport);
2903 __u16 srcp = ntohs(inet->inet_sport);
2904 u8 icsk_pending;
2905 int rx_queue;
2906 int state;
2907
2908 icsk_pending = smp_load_acquire(&icsk->icsk_pending);
2909 if (icsk_pending == ICSK_TIME_RETRANS ||
2910 icsk_pending == ICSK_TIME_REO_TIMEOUT ||
2911 icsk_pending == ICSK_TIME_LOSS_PROBE) {
2912 timer_active = 1;
2913 timer_expires = icsk->icsk_timeout;
2914 } else if (icsk_pending == ICSK_TIME_PROBE0) {
2915 timer_active = 4;
2916 timer_expires = icsk->icsk_timeout;
2917 } else if (timer_pending(&sk->sk_timer)) {
2918 timer_active = 2;
2919 timer_expires = sk->sk_timer.expires;
2920 } else {
2921 timer_active = 0;
2922 timer_expires = jiffies;
2923 }
2924
2925 state = inet_sk_state_load(sk);
2926 if (state == TCP_LISTEN)
2927 rx_queue = READ_ONCE(sk->sk_ack_backlog);
2928 else
2929 /* Because we don't lock the socket,
2930 * we might find a transient negative value.
2931 */
2932 rx_queue = max_t(int, READ_ONCE(tp->rcv_nxt) -
2933 READ_ONCE(tp->copied_seq), 0);
2934
2935 seq_printf(f, "%4d: %08X:%04X %08X:%04X %02X %08X:%08X %02X:%08lX "
2936 "%08X %5u %8d %lu %d %pK %lu %lu %u %u %d",
2937 i, src, srcp, dest, destp, state,
2938 READ_ONCE(tp->write_seq) - tp->snd_una,
2939 rx_queue,
2940 timer_active,
2941 jiffies_delta_to_clock_t(timer_expires - jiffies),
2942 icsk->icsk_retransmits,
2943 from_kuid_munged(seq_user_ns(f), sock_i_uid(sk)),
2944 icsk->icsk_probes_out,
2945 sock_i_ino(sk),
2946 refcount_read(&sk->sk_refcnt), sk,
2947 jiffies_to_clock_t(icsk->icsk_rto),
2948 jiffies_to_clock_t(icsk->icsk_ack.ato),
2949 (icsk->icsk_ack.quick << 1) | inet_csk_in_pingpong_mode(sk),
2950 tcp_snd_cwnd(tp),
2951 state == TCP_LISTEN ?
2952 fastopenq->max_qlen :
2953 (tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh));
2954}
2955
2956static void get_timewait4_sock(const struct inet_timewait_sock *tw,
2957 struct seq_file *f, int i)
2958{
2959 long delta = tw->tw_timer.expires - jiffies;
2960 __be32 dest, src;
2961 __u16 destp, srcp;
2962
2963 dest = tw->tw_daddr;
2964 src = tw->tw_rcv_saddr;
2965 destp = ntohs(tw->tw_dport);
2966 srcp = ntohs(tw->tw_sport);
2967
2968 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2969 " %02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK",
2970 i, src, srcp, dest, destp, READ_ONCE(tw->tw_substate), 0, 0,
2971 3, jiffies_delta_to_clock_t(delta), 0, 0, 0, 0,
2972 refcount_read(&tw->tw_refcnt), tw);
2973}
2974
2975#define TMPSZ 150
2976
2977static int tcp4_seq_show(struct seq_file *seq, void *v)
2978{
2979 struct tcp_iter_state *st;
2980 struct sock *sk = v;
2981
2982 seq_setwidth(seq, TMPSZ - 1);
2983 if (v == SEQ_START_TOKEN) {
2984 seq_puts(seq, " sl local_address rem_address st tx_queue "
2985 "rx_queue tr tm->when retrnsmt uid timeout "
2986 "inode");
2987 goto out;
2988 }
2989 st = seq->private;
2990
2991 if (sk->sk_state == TCP_TIME_WAIT)
2992 get_timewait4_sock(v, seq, st->num);
2993 else if (sk->sk_state == TCP_NEW_SYN_RECV)
2994 get_openreq4(v, seq, st->num);
2995 else
2996 get_tcp4_sock(v, seq, st->num);
2997out:
2998 seq_pad(seq, '\n');
2999 return 0;
3000}
3001
3002#ifdef CONFIG_BPF_SYSCALL
3003struct bpf_tcp_iter_state {
3004 struct tcp_iter_state state;
3005 unsigned int cur_sk;
3006 unsigned int end_sk;
3007 unsigned int max_sk;
3008 struct sock **batch;
3009 bool st_bucket_done;
3010};
3011
3012struct bpf_iter__tcp {
3013 __bpf_md_ptr(struct bpf_iter_meta *, meta);
3014 __bpf_md_ptr(struct sock_common *, sk_common);
3015 uid_t uid __aligned(8);
3016};
3017
3018static int tcp_prog_seq_show(struct bpf_prog *prog, struct bpf_iter_meta *meta,
3019 struct sock_common *sk_common, uid_t uid)
3020{
3021 struct bpf_iter__tcp ctx;
3022
3023 meta->seq_num--; /* skip SEQ_START_TOKEN */
3024 ctx.meta = meta;
3025 ctx.sk_common = sk_common;
3026 ctx.uid = uid;
3027 return bpf_iter_run_prog(prog, &ctx);
3028}
3029
3030static void bpf_iter_tcp_put_batch(struct bpf_tcp_iter_state *iter)
3031{
3032 while (iter->cur_sk < iter->end_sk)
3033 sock_gen_put(iter->batch[iter->cur_sk++]);
3034}
3035
3036static int bpf_iter_tcp_realloc_batch(struct bpf_tcp_iter_state *iter,
3037 unsigned int new_batch_sz)
3038{
3039 struct sock **new_batch;
3040
3041 new_batch = kvmalloc(sizeof(*new_batch) * new_batch_sz,
3042 GFP_USER | __GFP_NOWARN);
3043 if (!new_batch)
3044 return -ENOMEM;
3045
3046 bpf_iter_tcp_put_batch(iter);
3047 kvfree(iter->batch);
3048 iter->batch = new_batch;
3049 iter->max_sk = new_batch_sz;
3050
3051 return 0;
3052}
3053
3054static unsigned int bpf_iter_tcp_listening_batch(struct seq_file *seq,
3055 struct sock *start_sk)
3056{
3057 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo;
3058 struct bpf_tcp_iter_state *iter = seq->private;
3059 struct tcp_iter_state *st = &iter->state;
3060 struct hlist_nulls_node *node;
3061 unsigned int expected = 1;
3062 struct sock *sk;
3063
3064 sock_hold(start_sk);
3065 iter->batch[iter->end_sk++] = start_sk;
3066
3067 sk = sk_nulls_next(start_sk);
3068 sk_nulls_for_each_from(sk, node) {
3069 if (seq_sk_match(seq, sk)) {
3070 if (iter->end_sk < iter->max_sk) {
3071 sock_hold(sk);
3072 iter->batch[iter->end_sk++] = sk;
3073 }
3074 expected++;
3075 }
3076 }
3077 spin_unlock(&hinfo->lhash2[st->bucket].lock);
3078
3079 return expected;
3080}
3081
3082static unsigned int bpf_iter_tcp_established_batch(struct seq_file *seq,
3083 struct sock *start_sk)
3084{
3085 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo;
3086 struct bpf_tcp_iter_state *iter = seq->private;
3087 struct tcp_iter_state *st = &iter->state;
3088 struct hlist_nulls_node *node;
3089 unsigned int expected = 1;
3090 struct sock *sk;
3091
3092 sock_hold(start_sk);
3093 iter->batch[iter->end_sk++] = start_sk;
3094
3095 sk = sk_nulls_next(start_sk);
3096 sk_nulls_for_each_from(sk, node) {
3097 if (seq_sk_match(seq, sk)) {
3098 if (iter->end_sk < iter->max_sk) {
3099 sock_hold(sk);
3100 iter->batch[iter->end_sk++] = sk;
3101 }
3102 expected++;
3103 }
3104 }
3105 spin_unlock_bh(inet_ehash_lockp(hinfo, st->bucket));
3106
3107 return expected;
3108}
3109
3110static struct sock *bpf_iter_tcp_batch(struct seq_file *seq)
3111{
3112 struct inet_hashinfo *hinfo = seq_file_net(seq)->ipv4.tcp_death_row.hashinfo;
3113 struct bpf_tcp_iter_state *iter = seq->private;
3114 struct tcp_iter_state *st = &iter->state;
3115 unsigned int expected;
3116 bool resized = false;
3117 struct sock *sk;
3118
3119 /* The st->bucket is done. Directly advance to the next
3120 * bucket instead of having the tcp_seek_last_pos() to skip
3121 * one by one in the current bucket and eventually find out
3122 * it has to advance to the next bucket.
3123 */
3124 if (iter->st_bucket_done) {
3125 st->offset = 0;
3126 st->bucket++;
3127 if (st->state == TCP_SEQ_STATE_LISTENING &&
3128 st->bucket > hinfo->lhash2_mask) {
3129 st->state = TCP_SEQ_STATE_ESTABLISHED;
3130 st->bucket = 0;
3131 }
3132 }
3133
3134again:
3135 /* Get a new batch */
3136 iter->cur_sk = 0;
3137 iter->end_sk = 0;
3138 iter->st_bucket_done = false;
3139
3140 sk = tcp_seek_last_pos(seq);
3141 if (!sk)
3142 return NULL; /* Done */
3143
3144 if (st->state == TCP_SEQ_STATE_LISTENING)
3145 expected = bpf_iter_tcp_listening_batch(seq, sk);
3146 else
3147 expected = bpf_iter_tcp_established_batch(seq, sk);
3148
3149 if (iter->end_sk == expected) {
3150 iter->st_bucket_done = true;
3151 return sk;
3152 }
3153
3154 if (!resized && !bpf_iter_tcp_realloc_batch(iter, expected * 3 / 2)) {
3155 resized = true;
3156 goto again;
3157 }
3158
3159 return sk;
3160}
3161
3162static void *bpf_iter_tcp_seq_start(struct seq_file *seq, loff_t *pos)
3163{
3164 /* bpf iter does not support lseek, so it always
3165 * continue from where it was stop()-ped.
3166 */
3167 if (*pos)
3168 return bpf_iter_tcp_batch(seq);
3169
3170 return SEQ_START_TOKEN;
3171}
3172
3173static void *bpf_iter_tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
3174{
3175 struct bpf_tcp_iter_state *iter = seq->private;
3176 struct tcp_iter_state *st = &iter->state;
3177 struct sock *sk;
3178
3179 /* Whenever seq_next() is called, the iter->cur_sk is
3180 * done with seq_show(), so advance to the next sk in
3181 * the batch.
3182 */
3183 if (iter->cur_sk < iter->end_sk) {
3184 /* Keeping st->num consistent in tcp_iter_state.
3185 * bpf_iter_tcp does not use st->num.
3186 * meta.seq_num is used instead.
3187 */
3188 st->num++;
3189 /* Move st->offset to the next sk in the bucket such that
3190 * the future start() will resume at st->offset in
3191 * st->bucket. See tcp_seek_last_pos().
3192 */
3193 st->offset++;
3194 sock_gen_put(iter->batch[iter->cur_sk++]);
3195 }
3196
3197 if (iter->cur_sk < iter->end_sk)
3198 sk = iter->batch[iter->cur_sk];
3199 else
3200 sk = bpf_iter_tcp_batch(seq);
3201
3202 ++*pos;
3203 /* Keeping st->last_pos consistent in tcp_iter_state.
3204 * bpf iter does not do lseek, so st->last_pos always equals to *pos.
3205 */
3206 st->last_pos = *pos;
3207 return sk;
3208}
3209
3210static int bpf_iter_tcp_seq_show(struct seq_file *seq, void *v)
3211{
3212 struct bpf_iter_meta meta;
3213 struct bpf_prog *prog;
3214 struct sock *sk = v;
3215 uid_t uid;
3216 int ret;
3217
3218 if (v == SEQ_START_TOKEN)
3219 return 0;
3220
3221 if (sk_fullsock(sk))
3222 lock_sock(sk);
3223
3224 if (unlikely(sk_unhashed(sk))) {
3225 ret = SEQ_SKIP;
3226 goto unlock;
3227 }
3228
3229 if (sk->sk_state == TCP_TIME_WAIT) {
3230 uid = 0;
3231 } else if (sk->sk_state == TCP_NEW_SYN_RECV) {
3232 const struct request_sock *req = v;
3233
3234 uid = from_kuid_munged(seq_user_ns(seq),
3235 sock_i_uid(req->rsk_listener));
3236 } else {
3237 uid = from_kuid_munged(seq_user_ns(seq), sock_i_uid(sk));
3238 }
3239
3240 meta.seq = seq;
3241 prog = bpf_iter_get_info(&meta, false);
3242 ret = tcp_prog_seq_show(prog, &meta, v, uid);
3243
3244unlock:
3245 if (sk_fullsock(sk))
3246 release_sock(sk);
3247 return ret;
3248
3249}
3250
3251static void bpf_iter_tcp_seq_stop(struct seq_file *seq, void *v)
3252{
3253 struct bpf_tcp_iter_state *iter = seq->private;
3254 struct bpf_iter_meta meta;
3255 struct bpf_prog *prog;
3256
3257 if (!v) {
3258 meta.seq = seq;
3259 prog = bpf_iter_get_info(&meta, true);
3260 if (prog)
3261 (void)tcp_prog_seq_show(prog, &meta, v, 0);
3262 }
3263
3264 if (iter->cur_sk < iter->end_sk) {
3265 bpf_iter_tcp_put_batch(iter);
3266 iter->st_bucket_done = false;
3267 }
3268}
3269
3270static const struct seq_operations bpf_iter_tcp_seq_ops = {
3271 .show = bpf_iter_tcp_seq_show,
3272 .start = bpf_iter_tcp_seq_start,
3273 .next = bpf_iter_tcp_seq_next,
3274 .stop = bpf_iter_tcp_seq_stop,
3275};
3276#endif
3277static unsigned short seq_file_family(const struct seq_file *seq)
3278{
3279 const struct tcp_seq_afinfo *afinfo;
3280
3281#ifdef CONFIG_BPF_SYSCALL
3282 /* Iterated from bpf_iter. Let the bpf prog to filter instead. */
3283 if (seq->op == &bpf_iter_tcp_seq_ops)
3284 return AF_UNSPEC;
3285#endif
3286
3287 /* Iterated from proc fs */
3288 afinfo = pde_data(file_inode(seq->file));
3289 return afinfo->family;
3290}
3291
3292static const struct seq_operations tcp4_seq_ops = {
3293 .show = tcp4_seq_show,
3294 .start = tcp_seq_start,
3295 .next = tcp_seq_next,
3296 .stop = tcp_seq_stop,
3297};
3298
3299static struct tcp_seq_afinfo tcp4_seq_afinfo = {
3300 .family = AF_INET,
3301};
3302
3303static int __net_init tcp4_proc_init_net(struct net *net)
3304{
3305 if (!proc_create_net_data("tcp", 0444, net->proc_net, &tcp4_seq_ops,
3306 sizeof(struct tcp_iter_state), &tcp4_seq_afinfo))
3307 return -ENOMEM;
3308 return 0;
3309}
3310
3311static void __net_exit tcp4_proc_exit_net(struct net *net)
3312{
3313 remove_proc_entry("tcp", net->proc_net);
3314}
3315
3316static struct pernet_operations tcp4_net_ops = {
3317 .init = tcp4_proc_init_net,
3318 .exit = tcp4_proc_exit_net,
3319};
3320
3321int __init tcp4_proc_init(void)
3322{
3323 return register_pernet_subsys(&tcp4_net_ops);
3324}
3325
3326void tcp4_proc_exit(void)
3327{
3328 unregister_pernet_subsys(&tcp4_net_ops);
3329}
3330#endif /* CONFIG_PROC_FS */
3331
3332/* @wake is one when sk_stream_write_space() calls us.
3333 * This sends EPOLLOUT only if notsent_bytes is half the limit.
3334 * This mimics the strategy used in sock_def_write_space().
3335 */
3336bool tcp_stream_memory_free(const struct sock *sk, int wake)
3337{
3338 const struct tcp_sock *tp = tcp_sk(sk);
3339 u32 notsent_bytes = READ_ONCE(tp->write_seq) -
3340 READ_ONCE(tp->snd_nxt);
3341
3342 return (notsent_bytes << wake) < tcp_notsent_lowat(tp);
3343}
3344EXPORT_SYMBOL(tcp_stream_memory_free);
3345
3346struct proto tcp_prot = {
3347 .name = "TCP",
3348 .owner = THIS_MODULE,
3349 .close = tcp_close,
3350 .pre_connect = tcp_v4_pre_connect,
3351 .connect = tcp_v4_connect,
3352 .disconnect = tcp_disconnect,
3353 .accept = inet_csk_accept,
3354 .ioctl = tcp_ioctl,
3355 .init = tcp_v4_init_sock,
3356 .destroy = tcp_v4_destroy_sock,
3357 .shutdown = tcp_shutdown,
3358 .setsockopt = tcp_setsockopt,
3359 .getsockopt = tcp_getsockopt,
3360 .bpf_bypass_getsockopt = tcp_bpf_bypass_getsockopt,
3361 .keepalive = tcp_set_keepalive,
3362 .recvmsg = tcp_recvmsg,
3363 .sendmsg = tcp_sendmsg,
3364 .splice_eof = tcp_splice_eof,
3365 .backlog_rcv = tcp_v4_do_rcv,
3366 .release_cb = tcp_release_cb,
3367 .hash = inet_hash,
3368 .unhash = inet_unhash,
3369 .get_port = inet_csk_get_port,
3370 .put_port = inet_put_port,
3371#ifdef CONFIG_BPF_SYSCALL
3372 .psock_update_sk_prot = tcp_bpf_update_proto,
3373#endif
3374 .enter_memory_pressure = tcp_enter_memory_pressure,
3375 .leave_memory_pressure = tcp_leave_memory_pressure,
3376 .stream_memory_free = tcp_stream_memory_free,
3377 .sockets_allocated = &tcp_sockets_allocated,
3378 .orphan_count = &tcp_orphan_count,
3379
3380 .memory_allocated = &tcp_memory_allocated,
3381 .per_cpu_fw_alloc = &tcp_memory_per_cpu_fw_alloc,
3382
3383 .memory_pressure = &tcp_memory_pressure,
3384 .sysctl_mem = sysctl_tcp_mem,
3385 .sysctl_wmem_offset = offsetof(struct net, ipv4.sysctl_tcp_wmem),
3386 .sysctl_rmem_offset = offsetof(struct net, ipv4.sysctl_tcp_rmem),
3387 .max_header = MAX_TCP_HEADER,
3388 .obj_size = sizeof(struct tcp_sock),
3389 .slab_flags = SLAB_TYPESAFE_BY_RCU,
3390 .twsk_prot = &tcp_timewait_sock_ops,
3391 .rsk_prot = &tcp_request_sock_ops,
3392 .h.hashinfo = NULL,
3393 .no_autobind = true,
3394 .diag_destroy = tcp_abort,
3395};
3396EXPORT_SYMBOL(tcp_prot);
3397
3398static void __net_exit tcp_sk_exit(struct net *net)
3399{
3400 if (net->ipv4.tcp_congestion_control)
3401 bpf_module_put(net->ipv4.tcp_congestion_control,
3402 net->ipv4.tcp_congestion_control->owner);
3403}
3404
3405static void __net_init tcp_set_hashinfo(struct net *net)
3406{
3407 struct inet_hashinfo *hinfo;
3408 unsigned int ehash_entries;
3409 struct net *old_net;
3410
3411 if (net_eq(net, &init_net))
3412 goto fallback;
3413
3414 old_net = current->nsproxy->net_ns;
3415 ehash_entries = READ_ONCE(old_net->ipv4.sysctl_tcp_child_ehash_entries);
3416 if (!ehash_entries)
3417 goto fallback;
3418
3419 ehash_entries = roundup_pow_of_two(ehash_entries);
3420 hinfo = inet_pernet_hashinfo_alloc(&tcp_hashinfo, ehash_entries);
3421 if (!hinfo) {
3422 pr_warn("Failed to allocate TCP ehash (entries: %u) "
3423 "for a netns, fallback to the global one\n",
3424 ehash_entries);
3425fallback:
3426 hinfo = &tcp_hashinfo;
3427 ehash_entries = tcp_hashinfo.ehash_mask + 1;
3428 }
3429
3430 net->ipv4.tcp_death_row.hashinfo = hinfo;
3431 net->ipv4.tcp_death_row.sysctl_max_tw_buckets = ehash_entries / 2;
3432 net->ipv4.sysctl_max_syn_backlog = max(128U, ehash_entries / 128);
3433}
3434
3435static int __net_init tcp_sk_init(struct net *net)
3436{
3437 net->ipv4.sysctl_tcp_ecn = 2;
3438 net->ipv4.sysctl_tcp_ecn_fallback = 1;
3439
3440 net->ipv4.sysctl_tcp_base_mss = TCP_BASE_MSS;
3441 net->ipv4.sysctl_tcp_min_snd_mss = TCP_MIN_SND_MSS;
3442 net->ipv4.sysctl_tcp_probe_threshold = TCP_PROBE_THRESHOLD;
3443 net->ipv4.sysctl_tcp_probe_interval = TCP_PROBE_INTERVAL;
3444 net->ipv4.sysctl_tcp_mtu_probe_floor = TCP_MIN_SND_MSS;
3445
3446 net->ipv4.sysctl_tcp_keepalive_time = TCP_KEEPALIVE_TIME;
3447 net->ipv4.sysctl_tcp_keepalive_probes = TCP_KEEPALIVE_PROBES;
3448 net->ipv4.sysctl_tcp_keepalive_intvl = TCP_KEEPALIVE_INTVL;
3449
3450 net->ipv4.sysctl_tcp_syn_retries = TCP_SYN_RETRIES;
3451 net->ipv4.sysctl_tcp_synack_retries = TCP_SYNACK_RETRIES;
3452 net->ipv4.sysctl_tcp_syncookies = 1;
3453 net->ipv4.sysctl_tcp_reordering = TCP_FASTRETRANS_THRESH;
3454 net->ipv4.sysctl_tcp_retries1 = TCP_RETR1;
3455 net->ipv4.sysctl_tcp_retries2 = TCP_RETR2;
3456 net->ipv4.sysctl_tcp_orphan_retries = 0;
3457 net->ipv4.sysctl_tcp_fin_timeout = TCP_FIN_TIMEOUT;
3458 net->ipv4.sysctl_tcp_notsent_lowat = UINT_MAX;
3459 net->ipv4.sysctl_tcp_tw_reuse = 2;
3460 net->ipv4.sysctl_tcp_no_ssthresh_metrics_save = 1;
3461
3462 refcount_set(&net->ipv4.tcp_death_row.tw_refcount, 1);
3463 tcp_set_hashinfo(net);
3464
3465 net->ipv4.sysctl_tcp_sack = 1;
3466 net->ipv4.sysctl_tcp_window_scaling = 1;
3467 net->ipv4.sysctl_tcp_timestamps = 1;
3468 net->ipv4.sysctl_tcp_early_retrans = 3;
3469 net->ipv4.sysctl_tcp_recovery = TCP_RACK_LOSS_DETECTION;
3470 net->ipv4.sysctl_tcp_slow_start_after_idle = 1; /* By default, RFC2861 behavior. */
3471 net->ipv4.sysctl_tcp_retrans_collapse = 1;
3472 net->ipv4.sysctl_tcp_max_reordering = 300;
3473 net->ipv4.sysctl_tcp_dsack = 1;
3474 net->ipv4.sysctl_tcp_app_win = 31;
3475 net->ipv4.sysctl_tcp_adv_win_scale = 1;
3476 net->ipv4.sysctl_tcp_frto = 2;
3477 net->ipv4.sysctl_tcp_moderate_rcvbuf = 1;
3478 /* This limits the percentage of the congestion window which we
3479 * will allow a single TSO frame to consume. Building TSO frames
3480 * which are too large can cause TCP streams to be bursty.
3481 */
3482 net->ipv4.sysctl_tcp_tso_win_divisor = 3;
3483 /* Default TSQ limit of 16 TSO segments */
3484 net->ipv4.sysctl_tcp_limit_output_bytes = 16 * 65536;
3485
3486 /* rfc5961 challenge ack rate limiting, per net-ns, disabled by default. */
3487 net->ipv4.sysctl_tcp_challenge_ack_limit = INT_MAX;
3488
3489 net->ipv4.sysctl_tcp_min_tso_segs = 2;
3490 net->ipv4.sysctl_tcp_tso_rtt_log = 9; /* 2^9 = 512 usec */
3491 net->ipv4.sysctl_tcp_min_rtt_wlen = 300;
3492 net->ipv4.sysctl_tcp_autocorking = 1;
3493 net->ipv4.sysctl_tcp_invalid_ratelimit = HZ/2;
3494 net->ipv4.sysctl_tcp_pacing_ss_ratio = 200;
3495 net->ipv4.sysctl_tcp_pacing_ca_ratio = 120;
3496 if (net != &init_net) {
3497 memcpy(net->ipv4.sysctl_tcp_rmem,
3498 init_net.ipv4.sysctl_tcp_rmem,
3499 sizeof(init_net.ipv4.sysctl_tcp_rmem));
3500 memcpy(net->ipv4.sysctl_tcp_wmem,
3501 init_net.ipv4.sysctl_tcp_wmem,
3502 sizeof(init_net.ipv4.sysctl_tcp_wmem));
3503 }
3504 net->ipv4.sysctl_tcp_comp_sack_delay_ns = NSEC_PER_MSEC;
3505 net->ipv4.sysctl_tcp_comp_sack_slack_ns = 100 * NSEC_PER_USEC;
3506 net->ipv4.sysctl_tcp_comp_sack_nr = 44;
3507 net->ipv4.sysctl_tcp_backlog_ack_defer = 1;
3508 net->ipv4.sysctl_tcp_fastopen = TFO_CLIENT_ENABLE;
3509 net->ipv4.sysctl_tcp_fastopen_blackhole_timeout = 0;
3510 atomic_set(&net->ipv4.tfo_active_disable_times, 0);
3511
3512 /* Set default values for PLB */
3513 net->ipv4.sysctl_tcp_plb_enabled = 0; /* Disabled by default */
3514 net->ipv4.sysctl_tcp_plb_idle_rehash_rounds = 3;
3515 net->ipv4.sysctl_tcp_plb_rehash_rounds = 12;
3516 net->ipv4.sysctl_tcp_plb_suspend_rto_sec = 60;
3517 /* Default congestion threshold for PLB to mark a round is 50% */
3518 net->ipv4.sysctl_tcp_plb_cong_thresh = (1 << TCP_PLB_SCALE) / 2;
3519
3520 /* Reno is always built in */
3521 if (!net_eq(net, &init_net) &&
3522 bpf_try_module_get(init_net.ipv4.tcp_congestion_control,
3523 init_net.ipv4.tcp_congestion_control->owner))
3524 net->ipv4.tcp_congestion_control = init_net.ipv4.tcp_congestion_control;
3525 else
3526 net->ipv4.tcp_congestion_control = &tcp_reno;
3527
3528 net->ipv4.sysctl_tcp_syn_linear_timeouts = 4;
3529 net->ipv4.sysctl_tcp_shrink_window = 0;
3530
3531 net->ipv4.sysctl_tcp_pingpong_thresh = 1;
3532 net->ipv4.sysctl_tcp_rto_min_us = jiffies_to_usecs(TCP_RTO_MIN);
3533
3534 return 0;
3535}
3536
3537static void __net_exit tcp_sk_exit_batch(struct list_head *net_exit_list)
3538{
3539 struct net *net;
3540
3541 /* make sure concurrent calls to tcp_sk_exit_batch from net_cleanup_work
3542 * and failed setup_net error unwinding path are serialized.
3543 *
3544 * tcp_twsk_purge() handles twsk in any dead netns, not just those in
3545 * net_exit_list, the thread that dismantles a particular twsk must
3546 * do so without other thread progressing to refcount_dec_and_test() of
3547 * tcp_death_row.tw_refcount.
3548 */
3549 mutex_lock(&tcp_exit_batch_mutex);
3550
3551 tcp_twsk_purge(net_exit_list);
3552
3553 list_for_each_entry(net, net_exit_list, exit_list) {
3554 inet_pernet_hashinfo_free(net->ipv4.tcp_death_row.hashinfo);
3555 WARN_ON_ONCE(!refcount_dec_and_test(&net->ipv4.tcp_death_row.tw_refcount));
3556 tcp_fastopen_ctx_destroy(net);
3557 }
3558
3559 mutex_unlock(&tcp_exit_batch_mutex);
3560}
3561
3562static struct pernet_operations __net_initdata tcp_sk_ops = {
3563 .init = tcp_sk_init,
3564 .exit = tcp_sk_exit,
3565 .exit_batch = tcp_sk_exit_batch,
3566};
3567
3568#if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS)
3569DEFINE_BPF_ITER_FUNC(tcp, struct bpf_iter_meta *meta,
3570 struct sock_common *sk_common, uid_t uid)
3571
3572#define INIT_BATCH_SZ 16
3573
3574static int bpf_iter_init_tcp(void *priv_data, struct bpf_iter_aux_info *aux)
3575{
3576 struct bpf_tcp_iter_state *iter = priv_data;
3577 int err;
3578
3579 err = bpf_iter_init_seq_net(priv_data, aux);
3580 if (err)
3581 return err;
3582
3583 err = bpf_iter_tcp_realloc_batch(iter, INIT_BATCH_SZ);
3584 if (err) {
3585 bpf_iter_fini_seq_net(priv_data);
3586 return err;
3587 }
3588
3589 return 0;
3590}
3591
3592static void bpf_iter_fini_tcp(void *priv_data)
3593{
3594 struct bpf_tcp_iter_state *iter = priv_data;
3595
3596 bpf_iter_fini_seq_net(priv_data);
3597 kvfree(iter->batch);
3598}
3599
3600static const struct bpf_iter_seq_info tcp_seq_info = {
3601 .seq_ops = &bpf_iter_tcp_seq_ops,
3602 .init_seq_private = bpf_iter_init_tcp,
3603 .fini_seq_private = bpf_iter_fini_tcp,
3604 .seq_priv_size = sizeof(struct bpf_tcp_iter_state),
3605};
3606
3607static const struct bpf_func_proto *
3608bpf_iter_tcp_get_func_proto(enum bpf_func_id func_id,
3609 const struct bpf_prog *prog)
3610{
3611 switch (func_id) {
3612 case BPF_FUNC_setsockopt:
3613 return &bpf_sk_setsockopt_proto;
3614 case BPF_FUNC_getsockopt:
3615 return &bpf_sk_getsockopt_proto;
3616 default:
3617 return NULL;
3618 }
3619}
3620
3621static struct bpf_iter_reg tcp_reg_info = {
3622 .target = "tcp",
3623 .ctx_arg_info_size = 1,
3624 .ctx_arg_info = {
3625 { offsetof(struct bpf_iter__tcp, sk_common),
3626 PTR_TO_BTF_ID_OR_NULL | PTR_TRUSTED },
3627 },
3628 .get_func_proto = bpf_iter_tcp_get_func_proto,
3629 .seq_info = &tcp_seq_info,
3630};
3631
3632static void __init bpf_iter_register(void)
3633{
3634 tcp_reg_info.ctx_arg_info[0].btf_id = btf_sock_ids[BTF_SOCK_TYPE_SOCK_COMMON];
3635 if (bpf_iter_reg_target(&tcp_reg_info))
3636 pr_warn("Warning: could not register bpf iterator tcp\n");
3637}
3638
3639#endif
3640
3641void __init tcp_v4_init(void)
3642{
3643 int cpu, res;
3644
3645 for_each_possible_cpu(cpu) {
3646 struct sock *sk;
3647
3648 res = inet_ctl_sock_create(&sk, PF_INET, SOCK_RAW,
3649 IPPROTO_TCP, &init_net);
3650 if (res)
3651 panic("Failed to create the TCP control socket.\n");
3652 sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
3653
3654 /* Please enforce IP_DF and IPID==0 for RST and
3655 * ACK sent in SYN-RECV and TIME-WAIT state.
3656 */
3657 inet_sk(sk)->pmtudisc = IP_PMTUDISC_DO;
3658
3659 sk->sk_clockid = CLOCK_MONOTONIC;
3660
3661 per_cpu(ipv4_tcp_sk.sock, cpu) = sk;
3662 }
3663 if (register_pernet_subsys(&tcp_sk_ops))
3664 panic("Failed to create the TCP control socket.\n");
3665
3666#if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS)
3667 bpf_iter_register();
3668#endif
3669}