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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * TCP over IPv6
4 * Linux INET6 implementation
5 *
6 * Authors:
7 * Pedro Roque <roque@di.fc.ul.pt>
8 *
9 * Based on:
10 * linux/net/ipv4/tcp.c
11 * linux/net/ipv4/tcp_input.c
12 * linux/net/ipv4/tcp_output.c
13 *
14 * Fixes:
15 * Hideaki YOSHIFUJI : sin6_scope_id support
16 * YOSHIFUJI Hideaki @USAGI and: Support IPV6_V6ONLY socket option, which
17 * Alexey Kuznetsov allow both IPv4 and IPv6 sockets to bind
18 * a single port at the same time.
19 * YOSHIFUJI Hideaki @USAGI: convert /proc/net/tcp6 to seq_file.
20 */
21
22#include <linux/bottom_half.h>
23#include <linux/module.h>
24#include <linux/errno.h>
25#include <linux/types.h>
26#include <linux/socket.h>
27#include <linux/sockios.h>
28#include <linux/net.h>
29#include <linux/jiffies.h>
30#include <linux/in.h>
31#include <linux/in6.h>
32#include <linux/netdevice.h>
33#include <linux/init.h>
34#include <linux/jhash.h>
35#include <linux/ipsec.h>
36#include <linux/times.h>
37#include <linux/slab.h>
38#include <linux/uaccess.h>
39#include <linux/ipv6.h>
40#include <linux/icmpv6.h>
41#include <linux/random.h>
42#include <linux/indirect_call_wrapper.h>
43
44#include <net/tcp.h>
45#include <net/ndisc.h>
46#include <net/inet6_hashtables.h>
47#include <net/inet6_connection_sock.h>
48#include <net/ipv6.h>
49#include <net/transp_v6.h>
50#include <net/addrconf.h>
51#include <net/ip6_route.h>
52#include <net/ip6_checksum.h>
53#include <net/inet_ecn.h>
54#include <net/protocol.h>
55#include <net/xfrm.h>
56#include <net/snmp.h>
57#include <net/dsfield.h>
58#include <net/timewait_sock.h>
59#include <net/inet_common.h>
60#include <net/secure_seq.h>
61#include <net/busy_poll.h>
62
63#include <linux/proc_fs.h>
64#include <linux/seq_file.h>
65
66#include <crypto/hash.h>
67#include <linux/scatterlist.h>
68
69#include <trace/events/tcp.h>
70
71static void tcp_v6_send_reset(const struct sock *sk, struct sk_buff *skb);
72static void tcp_v6_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb,
73 struct request_sock *req);
74
75static int tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb);
76
77static const struct inet_connection_sock_af_ops ipv6_mapped;
78const struct inet_connection_sock_af_ops ipv6_specific;
79#ifdef CONFIG_TCP_MD5SIG
80static const struct tcp_sock_af_ops tcp_sock_ipv6_specific;
81static const struct tcp_sock_af_ops tcp_sock_ipv6_mapped_specific;
82#else
83static struct tcp_md5sig_key *tcp_v6_md5_do_lookup(const struct sock *sk,
84 const struct in6_addr *addr,
85 int l3index)
86{
87 return NULL;
88}
89#endif
90
91/* Helper returning the inet6 address from a given tcp socket.
92 * It can be used in TCP stack instead of inet6_sk(sk).
93 * This avoids a dereference and allow compiler optimizations.
94 * It is a specialized version of inet6_sk_generic().
95 */
96static struct ipv6_pinfo *tcp_inet6_sk(const struct sock *sk)
97{
98 unsigned int offset = sizeof(struct tcp6_sock) - sizeof(struct ipv6_pinfo);
99
100 return (struct ipv6_pinfo *)(((u8 *)sk) + offset);
101}
102
103static void inet6_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb)
104{
105 struct dst_entry *dst = skb_dst(skb);
106
107 if (dst && dst_hold_safe(dst)) {
108 const struct rt6_info *rt = (const struct rt6_info *)dst;
109
110 sk->sk_rx_dst = dst;
111 inet_sk(sk)->rx_dst_ifindex = skb->skb_iif;
112 tcp_inet6_sk(sk)->rx_dst_cookie = rt6_get_cookie(rt);
113 }
114}
115
116static u32 tcp_v6_init_seq(const struct sk_buff *skb)
117{
118 return secure_tcpv6_seq(ipv6_hdr(skb)->daddr.s6_addr32,
119 ipv6_hdr(skb)->saddr.s6_addr32,
120 tcp_hdr(skb)->dest,
121 tcp_hdr(skb)->source);
122}
123
124static u32 tcp_v6_init_ts_off(const struct net *net, const struct sk_buff *skb)
125{
126 return secure_tcpv6_ts_off(net, ipv6_hdr(skb)->daddr.s6_addr32,
127 ipv6_hdr(skb)->saddr.s6_addr32);
128}
129
130static int tcp_v6_pre_connect(struct sock *sk, struct sockaddr *uaddr,
131 int addr_len)
132{
133 /* This check is replicated from tcp_v6_connect() and intended to
134 * prevent BPF program called below from accessing bytes that are out
135 * of the bound specified by user in addr_len.
136 */
137 if (addr_len < SIN6_LEN_RFC2133)
138 return -EINVAL;
139
140 sock_owned_by_me(sk);
141
142 return BPF_CGROUP_RUN_PROG_INET6_CONNECT(sk, uaddr);
143}
144
145static int tcp_v6_connect(struct sock *sk, struct sockaddr *uaddr,
146 int addr_len)
147{
148 struct sockaddr_in6 *usin = (struct sockaddr_in6 *) uaddr;
149 struct inet_sock *inet = inet_sk(sk);
150 struct inet_connection_sock *icsk = inet_csk(sk);
151 struct ipv6_pinfo *np = tcp_inet6_sk(sk);
152 struct tcp_sock *tp = tcp_sk(sk);
153 struct in6_addr *saddr = NULL, *final_p, final;
154 struct ipv6_txoptions *opt;
155 struct flowi6 fl6;
156 struct dst_entry *dst;
157 int addr_type;
158 int err;
159 struct inet_timewait_death_row *tcp_death_row = &sock_net(sk)->ipv4.tcp_death_row;
160
161 if (addr_len < SIN6_LEN_RFC2133)
162 return -EINVAL;
163
164 if (usin->sin6_family != AF_INET6)
165 return -EAFNOSUPPORT;
166
167 memset(&fl6, 0, sizeof(fl6));
168
169 if (np->sndflow) {
170 fl6.flowlabel = usin->sin6_flowinfo&IPV6_FLOWINFO_MASK;
171 IP6_ECN_flow_init(fl6.flowlabel);
172 if (fl6.flowlabel&IPV6_FLOWLABEL_MASK) {
173 struct ip6_flowlabel *flowlabel;
174 flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
175 if (IS_ERR(flowlabel))
176 return -EINVAL;
177 fl6_sock_release(flowlabel);
178 }
179 }
180
181 /*
182 * connect() to INADDR_ANY means loopback (BSD'ism).
183 */
184
185 if (ipv6_addr_any(&usin->sin6_addr)) {
186 if (ipv6_addr_v4mapped(&sk->sk_v6_rcv_saddr))
187 ipv6_addr_set_v4mapped(htonl(INADDR_LOOPBACK),
188 &usin->sin6_addr);
189 else
190 usin->sin6_addr = in6addr_loopback;
191 }
192
193 addr_type = ipv6_addr_type(&usin->sin6_addr);
194
195 if (addr_type & IPV6_ADDR_MULTICAST)
196 return -ENETUNREACH;
197
198 if (addr_type&IPV6_ADDR_LINKLOCAL) {
199 if (addr_len >= sizeof(struct sockaddr_in6) &&
200 usin->sin6_scope_id) {
201 /* If interface is set while binding, indices
202 * must coincide.
203 */
204 if (!sk_dev_equal_l3scope(sk, usin->sin6_scope_id))
205 return -EINVAL;
206
207 sk->sk_bound_dev_if = usin->sin6_scope_id;
208 }
209
210 /* Connect to link-local address requires an interface */
211 if (!sk->sk_bound_dev_if)
212 return -EINVAL;
213 }
214
215 if (tp->rx_opt.ts_recent_stamp &&
216 !ipv6_addr_equal(&sk->sk_v6_daddr, &usin->sin6_addr)) {
217 tp->rx_opt.ts_recent = 0;
218 tp->rx_opt.ts_recent_stamp = 0;
219 WRITE_ONCE(tp->write_seq, 0);
220 }
221
222 sk->sk_v6_daddr = usin->sin6_addr;
223 np->flow_label = fl6.flowlabel;
224
225 /*
226 * TCP over IPv4
227 */
228
229 if (addr_type & IPV6_ADDR_MAPPED) {
230 u32 exthdrlen = icsk->icsk_ext_hdr_len;
231 struct sockaddr_in sin;
232
233 if (__ipv6_only_sock(sk))
234 return -ENETUNREACH;
235
236 sin.sin_family = AF_INET;
237 sin.sin_port = usin->sin6_port;
238 sin.sin_addr.s_addr = usin->sin6_addr.s6_addr32[3];
239
240 icsk->icsk_af_ops = &ipv6_mapped;
241 if (sk_is_mptcp(sk))
242 mptcpv6_handle_mapped(sk, true);
243 sk->sk_backlog_rcv = tcp_v4_do_rcv;
244#ifdef CONFIG_TCP_MD5SIG
245 tp->af_specific = &tcp_sock_ipv6_mapped_specific;
246#endif
247
248 err = tcp_v4_connect(sk, (struct sockaddr *)&sin, sizeof(sin));
249
250 if (err) {
251 icsk->icsk_ext_hdr_len = exthdrlen;
252 icsk->icsk_af_ops = &ipv6_specific;
253 if (sk_is_mptcp(sk))
254 mptcpv6_handle_mapped(sk, false);
255 sk->sk_backlog_rcv = tcp_v6_do_rcv;
256#ifdef CONFIG_TCP_MD5SIG
257 tp->af_specific = &tcp_sock_ipv6_specific;
258#endif
259 goto failure;
260 }
261 np->saddr = sk->sk_v6_rcv_saddr;
262
263 return err;
264 }
265
266 if (!ipv6_addr_any(&sk->sk_v6_rcv_saddr))
267 saddr = &sk->sk_v6_rcv_saddr;
268
269 fl6.flowi6_proto = IPPROTO_TCP;
270 fl6.daddr = sk->sk_v6_daddr;
271 fl6.saddr = saddr ? *saddr : np->saddr;
272 fl6.flowi6_oif = sk->sk_bound_dev_if;
273 fl6.flowi6_mark = sk->sk_mark;
274 fl6.fl6_dport = usin->sin6_port;
275 fl6.fl6_sport = inet->inet_sport;
276 fl6.flowi6_uid = sk->sk_uid;
277
278 opt = rcu_dereference_protected(np->opt, lockdep_sock_is_held(sk));
279 final_p = fl6_update_dst(&fl6, opt, &final);
280
281 security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));
282
283 dst = ip6_dst_lookup_flow(sock_net(sk), sk, &fl6, final_p);
284 if (IS_ERR(dst)) {
285 err = PTR_ERR(dst);
286 goto failure;
287 }
288
289 if (!saddr) {
290 saddr = &fl6.saddr;
291 sk->sk_v6_rcv_saddr = *saddr;
292 }
293
294 /* set the source address */
295 np->saddr = *saddr;
296 inet->inet_rcv_saddr = LOOPBACK4_IPV6;
297
298 sk->sk_gso_type = SKB_GSO_TCPV6;
299 ip6_dst_store(sk, dst, NULL, NULL);
300
301 icsk->icsk_ext_hdr_len = 0;
302 if (opt)
303 icsk->icsk_ext_hdr_len = opt->opt_flen +
304 opt->opt_nflen;
305
306 tp->rx_opt.mss_clamp = IPV6_MIN_MTU - sizeof(struct tcphdr) - sizeof(struct ipv6hdr);
307
308 inet->inet_dport = usin->sin6_port;
309
310 tcp_set_state(sk, TCP_SYN_SENT);
311 err = inet6_hash_connect(tcp_death_row, sk);
312 if (err)
313 goto late_failure;
314
315 sk_set_txhash(sk);
316
317 if (likely(!tp->repair)) {
318 if (!tp->write_seq)
319 WRITE_ONCE(tp->write_seq,
320 secure_tcpv6_seq(np->saddr.s6_addr32,
321 sk->sk_v6_daddr.s6_addr32,
322 inet->inet_sport,
323 inet->inet_dport));
324 tp->tsoffset = secure_tcpv6_ts_off(sock_net(sk),
325 np->saddr.s6_addr32,
326 sk->sk_v6_daddr.s6_addr32);
327 }
328
329 if (tcp_fastopen_defer_connect(sk, &err))
330 return err;
331 if (err)
332 goto late_failure;
333
334 err = tcp_connect(sk);
335 if (err)
336 goto late_failure;
337
338 return 0;
339
340late_failure:
341 tcp_set_state(sk, TCP_CLOSE);
342failure:
343 inet->inet_dport = 0;
344 sk->sk_route_caps = 0;
345 return err;
346}
347
348static void tcp_v6_mtu_reduced(struct sock *sk)
349{
350 struct dst_entry *dst;
351
352 if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE))
353 return;
354
355 dst = inet6_csk_update_pmtu(sk, tcp_sk(sk)->mtu_info);
356 if (!dst)
357 return;
358
359 if (inet_csk(sk)->icsk_pmtu_cookie > dst_mtu(dst)) {
360 tcp_sync_mss(sk, dst_mtu(dst));
361 tcp_simple_retransmit(sk);
362 }
363}
364
365static int tcp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
366 u8 type, u8 code, int offset, __be32 info)
367{
368 const struct ipv6hdr *hdr = (const struct ipv6hdr *)skb->data;
369 const struct tcphdr *th = (struct tcphdr *)(skb->data+offset);
370 struct net *net = dev_net(skb->dev);
371 struct request_sock *fastopen;
372 struct ipv6_pinfo *np;
373 struct tcp_sock *tp;
374 __u32 seq, snd_una;
375 struct sock *sk;
376 bool fatal;
377 int err;
378
379 sk = __inet6_lookup_established(net, &tcp_hashinfo,
380 &hdr->daddr, th->dest,
381 &hdr->saddr, ntohs(th->source),
382 skb->dev->ifindex, inet6_sdif(skb));
383
384 if (!sk) {
385 __ICMP6_INC_STATS(net, __in6_dev_get(skb->dev),
386 ICMP6_MIB_INERRORS);
387 return -ENOENT;
388 }
389
390 if (sk->sk_state == TCP_TIME_WAIT) {
391 inet_twsk_put(inet_twsk(sk));
392 return 0;
393 }
394 seq = ntohl(th->seq);
395 fatal = icmpv6_err_convert(type, code, &err);
396 if (sk->sk_state == TCP_NEW_SYN_RECV) {
397 tcp_req_err(sk, seq, fatal);
398 return 0;
399 }
400
401 bh_lock_sock(sk);
402 if (sock_owned_by_user(sk) && type != ICMPV6_PKT_TOOBIG)
403 __NET_INC_STATS(net, LINUX_MIB_LOCKDROPPEDICMPS);
404
405 if (sk->sk_state == TCP_CLOSE)
406 goto out;
407
408 if (ipv6_hdr(skb)->hop_limit < tcp_inet6_sk(sk)->min_hopcount) {
409 __NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP);
410 goto out;
411 }
412
413 tp = tcp_sk(sk);
414 /* XXX (TFO) - tp->snd_una should be ISN (tcp_create_openreq_child() */
415 fastopen = rcu_dereference(tp->fastopen_rsk);
416 snd_una = fastopen ? tcp_rsk(fastopen)->snt_isn : tp->snd_una;
417 if (sk->sk_state != TCP_LISTEN &&
418 !between(seq, snd_una, tp->snd_nxt)) {
419 __NET_INC_STATS(net, LINUX_MIB_OUTOFWINDOWICMPS);
420 goto out;
421 }
422
423 np = tcp_inet6_sk(sk);
424
425 if (type == NDISC_REDIRECT) {
426 if (!sock_owned_by_user(sk)) {
427 struct dst_entry *dst = __sk_dst_check(sk, np->dst_cookie);
428
429 if (dst)
430 dst->ops->redirect(dst, sk, skb);
431 }
432 goto out;
433 }
434
435 if (type == ICMPV6_PKT_TOOBIG) {
436 /* We are not interested in TCP_LISTEN and open_requests
437 * (SYN-ACKs send out by Linux are always <576bytes so
438 * they should go through unfragmented).
439 */
440 if (sk->sk_state == TCP_LISTEN)
441 goto out;
442
443 if (!ip6_sk_accept_pmtu(sk))
444 goto out;
445
446 tp->mtu_info = ntohl(info);
447 if (!sock_owned_by_user(sk))
448 tcp_v6_mtu_reduced(sk);
449 else if (!test_and_set_bit(TCP_MTU_REDUCED_DEFERRED,
450 &sk->sk_tsq_flags))
451 sock_hold(sk);
452 goto out;
453 }
454
455
456 /* Might be for an request_sock */
457 switch (sk->sk_state) {
458 case TCP_SYN_SENT:
459 case TCP_SYN_RECV:
460 /* Only in fast or simultaneous open. If a fast open socket is
461 * is already accepted it is treated as a connected one below.
462 */
463 if (fastopen && !fastopen->sk)
464 break;
465
466 ipv6_icmp_error(sk, skb, err, th->dest, ntohl(info), (u8 *)th);
467
468 if (!sock_owned_by_user(sk)) {
469 sk->sk_err = err;
470 sk->sk_error_report(sk); /* Wake people up to see the error (see connect in sock.c) */
471
472 tcp_done(sk);
473 } else
474 sk->sk_err_soft = err;
475 goto out;
476 case TCP_LISTEN:
477 break;
478 default:
479 /* check if this ICMP message allows revert of backoff.
480 * (see RFC 6069)
481 */
482 if (!fastopen && type == ICMPV6_DEST_UNREACH &&
483 code == ICMPV6_NOROUTE)
484 tcp_ld_RTO_revert(sk, seq);
485 }
486
487 if (!sock_owned_by_user(sk) && np->recverr) {
488 sk->sk_err = err;
489 sk->sk_error_report(sk);
490 } else
491 sk->sk_err_soft = err;
492
493out:
494 bh_unlock_sock(sk);
495 sock_put(sk);
496 return 0;
497}
498
499
500static int tcp_v6_send_synack(const struct sock *sk, struct dst_entry *dst,
501 struct flowi *fl,
502 struct request_sock *req,
503 struct tcp_fastopen_cookie *foc,
504 enum tcp_synack_type synack_type)
505{
506 struct inet_request_sock *ireq = inet_rsk(req);
507 struct ipv6_pinfo *np = tcp_inet6_sk(sk);
508 struct ipv6_txoptions *opt;
509 struct flowi6 *fl6 = &fl->u.ip6;
510 struct sk_buff *skb;
511 int err = -ENOMEM;
512
513 /* First, grab a route. */
514 if (!dst && (dst = inet6_csk_route_req(sk, fl6, req,
515 IPPROTO_TCP)) == NULL)
516 goto done;
517
518 skb = tcp_make_synack(sk, dst, req, foc, synack_type);
519
520 if (skb) {
521 __tcp_v6_send_check(skb, &ireq->ir_v6_loc_addr,
522 &ireq->ir_v6_rmt_addr);
523
524 fl6->daddr = ireq->ir_v6_rmt_addr;
525 if (np->repflow && ireq->pktopts)
526 fl6->flowlabel = ip6_flowlabel(ipv6_hdr(ireq->pktopts));
527
528 rcu_read_lock();
529 opt = ireq->ipv6_opt;
530 if (!opt)
531 opt = rcu_dereference(np->opt);
532 err = ip6_xmit(sk, skb, fl6, sk->sk_mark, opt, np->tclass,
533 sk->sk_priority);
534 rcu_read_unlock();
535 err = net_xmit_eval(err);
536 }
537
538done:
539 return err;
540}
541
542
543static void tcp_v6_reqsk_destructor(struct request_sock *req)
544{
545 kfree(inet_rsk(req)->ipv6_opt);
546 kfree_skb(inet_rsk(req)->pktopts);
547}
548
549#ifdef CONFIG_TCP_MD5SIG
550static struct tcp_md5sig_key *tcp_v6_md5_do_lookup(const struct sock *sk,
551 const struct in6_addr *addr,
552 int l3index)
553{
554 return tcp_md5_do_lookup(sk, l3index,
555 (union tcp_md5_addr *)addr, AF_INET6);
556}
557
558static struct tcp_md5sig_key *tcp_v6_md5_lookup(const struct sock *sk,
559 const struct sock *addr_sk)
560{
561 int l3index;
562
563 l3index = l3mdev_master_ifindex_by_index(sock_net(sk),
564 addr_sk->sk_bound_dev_if);
565 return tcp_v6_md5_do_lookup(sk, &addr_sk->sk_v6_daddr,
566 l3index);
567}
568
569static int tcp_v6_parse_md5_keys(struct sock *sk, int optname,
570 sockptr_t optval, int optlen)
571{
572 struct tcp_md5sig cmd;
573 struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)&cmd.tcpm_addr;
574 int l3index = 0;
575 u8 prefixlen;
576
577 if (optlen < sizeof(cmd))
578 return -EINVAL;
579
580 if (copy_from_sockptr(&cmd, optval, sizeof(cmd)))
581 return -EFAULT;
582
583 if (sin6->sin6_family != AF_INET6)
584 return -EINVAL;
585
586 if (optname == TCP_MD5SIG_EXT &&
587 cmd.tcpm_flags & TCP_MD5SIG_FLAG_PREFIX) {
588 prefixlen = cmd.tcpm_prefixlen;
589 if (prefixlen > 128 || (ipv6_addr_v4mapped(&sin6->sin6_addr) &&
590 prefixlen > 32))
591 return -EINVAL;
592 } else {
593 prefixlen = ipv6_addr_v4mapped(&sin6->sin6_addr) ? 32 : 128;
594 }
595
596 if (optname == TCP_MD5SIG_EXT &&
597 cmd.tcpm_flags & TCP_MD5SIG_FLAG_IFINDEX) {
598 struct net_device *dev;
599
600 rcu_read_lock();
601 dev = dev_get_by_index_rcu(sock_net(sk), cmd.tcpm_ifindex);
602 if (dev && netif_is_l3_master(dev))
603 l3index = dev->ifindex;
604 rcu_read_unlock();
605
606 /* ok to reference set/not set outside of rcu;
607 * right now device MUST be an L3 master
608 */
609 if (!dev || !l3index)
610 return -EINVAL;
611 }
612
613 if (!cmd.tcpm_keylen) {
614 if (ipv6_addr_v4mapped(&sin6->sin6_addr))
615 return tcp_md5_do_del(sk, (union tcp_md5_addr *)&sin6->sin6_addr.s6_addr32[3],
616 AF_INET, prefixlen,
617 l3index);
618 return tcp_md5_do_del(sk, (union tcp_md5_addr *)&sin6->sin6_addr,
619 AF_INET6, prefixlen, l3index);
620 }
621
622 if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN)
623 return -EINVAL;
624
625 if (ipv6_addr_v4mapped(&sin6->sin6_addr))
626 return tcp_md5_do_add(sk, (union tcp_md5_addr *)&sin6->sin6_addr.s6_addr32[3],
627 AF_INET, prefixlen, l3index,
628 cmd.tcpm_key, cmd.tcpm_keylen,
629 GFP_KERNEL);
630
631 return tcp_md5_do_add(sk, (union tcp_md5_addr *)&sin6->sin6_addr,
632 AF_INET6, prefixlen, l3index,
633 cmd.tcpm_key, cmd.tcpm_keylen, GFP_KERNEL);
634}
635
636static int tcp_v6_md5_hash_headers(struct tcp_md5sig_pool *hp,
637 const struct in6_addr *daddr,
638 const struct in6_addr *saddr,
639 const struct tcphdr *th, int nbytes)
640{
641 struct tcp6_pseudohdr *bp;
642 struct scatterlist sg;
643 struct tcphdr *_th;
644
645 bp = hp->scratch;
646 /* 1. TCP pseudo-header (RFC2460) */
647 bp->saddr = *saddr;
648 bp->daddr = *daddr;
649 bp->protocol = cpu_to_be32(IPPROTO_TCP);
650 bp->len = cpu_to_be32(nbytes);
651
652 _th = (struct tcphdr *)(bp + 1);
653 memcpy(_th, th, sizeof(*th));
654 _th->check = 0;
655
656 sg_init_one(&sg, bp, sizeof(*bp) + sizeof(*th));
657 ahash_request_set_crypt(hp->md5_req, &sg, NULL,
658 sizeof(*bp) + sizeof(*th));
659 return crypto_ahash_update(hp->md5_req);
660}
661
662static int tcp_v6_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key,
663 const struct in6_addr *daddr, struct in6_addr *saddr,
664 const struct tcphdr *th)
665{
666 struct tcp_md5sig_pool *hp;
667 struct ahash_request *req;
668
669 hp = tcp_get_md5sig_pool();
670 if (!hp)
671 goto clear_hash_noput;
672 req = hp->md5_req;
673
674 if (crypto_ahash_init(req))
675 goto clear_hash;
676 if (tcp_v6_md5_hash_headers(hp, daddr, saddr, th, th->doff << 2))
677 goto clear_hash;
678 if (tcp_md5_hash_key(hp, key))
679 goto clear_hash;
680 ahash_request_set_crypt(req, NULL, md5_hash, 0);
681 if (crypto_ahash_final(req))
682 goto clear_hash;
683
684 tcp_put_md5sig_pool();
685 return 0;
686
687clear_hash:
688 tcp_put_md5sig_pool();
689clear_hash_noput:
690 memset(md5_hash, 0, 16);
691 return 1;
692}
693
694static int tcp_v6_md5_hash_skb(char *md5_hash,
695 const struct tcp_md5sig_key *key,
696 const struct sock *sk,
697 const struct sk_buff *skb)
698{
699 const struct in6_addr *saddr, *daddr;
700 struct tcp_md5sig_pool *hp;
701 struct ahash_request *req;
702 const struct tcphdr *th = tcp_hdr(skb);
703
704 if (sk) { /* valid for establish/request sockets */
705 saddr = &sk->sk_v6_rcv_saddr;
706 daddr = &sk->sk_v6_daddr;
707 } else {
708 const struct ipv6hdr *ip6h = ipv6_hdr(skb);
709 saddr = &ip6h->saddr;
710 daddr = &ip6h->daddr;
711 }
712
713 hp = tcp_get_md5sig_pool();
714 if (!hp)
715 goto clear_hash_noput;
716 req = hp->md5_req;
717
718 if (crypto_ahash_init(req))
719 goto clear_hash;
720
721 if (tcp_v6_md5_hash_headers(hp, daddr, saddr, th, skb->len))
722 goto clear_hash;
723 if (tcp_md5_hash_skb_data(hp, skb, th->doff << 2))
724 goto clear_hash;
725 if (tcp_md5_hash_key(hp, key))
726 goto clear_hash;
727 ahash_request_set_crypt(req, NULL, md5_hash, 0);
728 if (crypto_ahash_final(req))
729 goto clear_hash;
730
731 tcp_put_md5sig_pool();
732 return 0;
733
734clear_hash:
735 tcp_put_md5sig_pool();
736clear_hash_noput:
737 memset(md5_hash, 0, 16);
738 return 1;
739}
740
741#endif
742
743static bool tcp_v6_inbound_md5_hash(const struct sock *sk,
744 const struct sk_buff *skb,
745 int dif, int sdif)
746{
747#ifdef CONFIG_TCP_MD5SIG
748 const __u8 *hash_location = NULL;
749 struct tcp_md5sig_key *hash_expected;
750 const struct ipv6hdr *ip6h = ipv6_hdr(skb);
751 const struct tcphdr *th = tcp_hdr(skb);
752 int genhash, l3index;
753 u8 newhash[16];
754
755 /* sdif set, means packet ingressed via a device
756 * in an L3 domain and dif is set to the l3mdev
757 */
758 l3index = sdif ? dif : 0;
759
760 hash_expected = tcp_v6_md5_do_lookup(sk, &ip6h->saddr, l3index);
761 hash_location = tcp_parse_md5sig_option(th);
762
763 /* We've parsed the options - do we have a hash? */
764 if (!hash_expected && !hash_location)
765 return false;
766
767 if (hash_expected && !hash_location) {
768 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5NOTFOUND);
769 return true;
770 }
771
772 if (!hash_expected && hash_location) {
773 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5UNEXPECTED);
774 return true;
775 }
776
777 /* check the signature */
778 genhash = tcp_v6_md5_hash_skb(newhash,
779 hash_expected,
780 NULL, skb);
781
782 if (genhash || memcmp(hash_location, newhash, 16) != 0) {
783 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5FAILURE);
784 net_info_ratelimited("MD5 Hash %s for [%pI6c]:%u->[%pI6c]:%u L3 index %d\n",
785 genhash ? "failed" : "mismatch",
786 &ip6h->saddr, ntohs(th->source),
787 &ip6h->daddr, ntohs(th->dest), l3index);
788 return true;
789 }
790#endif
791 return false;
792}
793
794static void tcp_v6_init_req(struct request_sock *req,
795 const struct sock *sk_listener,
796 struct sk_buff *skb)
797{
798 bool l3_slave = ipv6_l3mdev_skb(TCP_SKB_CB(skb)->header.h6.flags);
799 struct inet_request_sock *ireq = inet_rsk(req);
800 const struct ipv6_pinfo *np = tcp_inet6_sk(sk_listener);
801
802 ireq->ir_v6_rmt_addr = ipv6_hdr(skb)->saddr;
803 ireq->ir_v6_loc_addr = ipv6_hdr(skb)->daddr;
804
805 /* So that link locals have meaning */
806 if ((!sk_listener->sk_bound_dev_if || l3_slave) &&
807 ipv6_addr_type(&ireq->ir_v6_rmt_addr) & IPV6_ADDR_LINKLOCAL)
808 ireq->ir_iif = tcp_v6_iif(skb);
809
810 if (!TCP_SKB_CB(skb)->tcp_tw_isn &&
811 (ipv6_opt_accepted(sk_listener, skb, &TCP_SKB_CB(skb)->header.h6) ||
812 np->rxopt.bits.rxinfo ||
813 np->rxopt.bits.rxoinfo || np->rxopt.bits.rxhlim ||
814 np->rxopt.bits.rxohlim || np->repflow)) {
815 refcount_inc(&skb->users);
816 ireq->pktopts = skb;
817 }
818}
819
820static struct dst_entry *tcp_v6_route_req(const struct sock *sk,
821 struct flowi *fl,
822 const struct request_sock *req)
823{
824 return inet6_csk_route_req(sk, &fl->u.ip6, req, IPPROTO_TCP);
825}
826
827struct request_sock_ops tcp6_request_sock_ops __read_mostly = {
828 .family = AF_INET6,
829 .obj_size = sizeof(struct tcp6_request_sock),
830 .rtx_syn_ack = tcp_rtx_synack,
831 .send_ack = tcp_v6_reqsk_send_ack,
832 .destructor = tcp_v6_reqsk_destructor,
833 .send_reset = tcp_v6_send_reset,
834 .syn_ack_timeout = tcp_syn_ack_timeout,
835};
836
837const struct tcp_request_sock_ops tcp_request_sock_ipv6_ops = {
838 .mss_clamp = IPV6_MIN_MTU - sizeof(struct tcphdr) -
839 sizeof(struct ipv6hdr),
840#ifdef CONFIG_TCP_MD5SIG
841 .req_md5_lookup = tcp_v6_md5_lookup,
842 .calc_md5_hash = tcp_v6_md5_hash_skb,
843#endif
844 .init_req = tcp_v6_init_req,
845#ifdef CONFIG_SYN_COOKIES
846 .cookie_init_seq = cookie_v6_init_sequence,
847#endif
848 .route_req = tcp_v6_route_req,
849 .init_seq = tcp_v6_init_seq,
850 .init_ts_off = tcp_v6_init_ts_off,
851 .send_synack = tcp_v6_send_synack,
852};
853
854static void tcp_v6_send_response(const struct sock *sk, struct sk_buff *skb, u32 seq,
855 u32 ack, u32 win, u32 tsval, u32 tsecr,
856 int oif, struct tcp_md5sig_key *key, int rst,
857 u8 tclass, __be32 label, u32 priority)
858{
859 const struct tcphdr *th = tcp_hdr(skb);
860 struct tcphdr *t1;
861 struct sk_buff *buff;
862 struct flowi6 fl6;
863 struct net *net = sk ? sock_net(sk) : dev_net(skb_dst(skb)->dev);
864 struct sock *ctl_sk = net->ipv6.tcp_sk;
865 unsigned int tot_len = sizeof(struct tcphdr);
866 struct dst_entry *dst;
867 __be32 *topt;
868 __u32 mark = 0;
869
870 if (tsecr)
871 tot_len += TCPOLEN_TSTAMP_ALIGNED;
872#ifdef CONFIG_TCP_MD5SIG
873 if (key)
874 tot_len += TCPOLEN_MD5SIG_ALIGNED;
875#endif
876
877 buff = alloc_skb(MAX_HEADER + sizeof(struct ipv6hdr) + tot_len,
878 GFP_ATOMIC);
879 if (!buff)
880 return;
881
882 skb_reserve(buff, MAX_HEADER + sizeof(struct ipv6hdr) + tot_len);
883
884 t1 = skb_push(buff, tot_len);
885 skb_reset_transport_header(buff);
886
887 /* Swap the send and the receive. */
888 memset(t1, 0, sizeof(*t1));
889 t1->dest = th->source;
890 t1->source = th->dest;
891 t1->doff = tot_len / 4;
892 t1->seq = htonl(seq);
893 t1->ack_seq = htonl(ack);
894 t1->ack = !rst || !th->ack;
895 t1->rst = rst;
896 t1->window = htons(win);
897
898 topt = (__be32 *)(t1 + 1);
899
900 if (tsecr) {
901 *topt++ = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
902 (TCPOPT_TIMESTAMP << 8) | TCPOLEN_TIMESTAMP);
903 *topt++ = htonl(tsval);
904 *topt++ = htonl(tsecr);
905 }
906
907#ifdef CONFIG_TCP_MD5SIG
908 if (key) {
909 *topt++ = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
910 (TCPOPT_MD5SIG << 8) | TCPOLEN_MD5SIG);
911 tcp_v6_md5_hash_hdr((__u8 *)topt, key,
912 &ipv6_hdr(skb)->saddr,
913 &ipv6_hdr(skb)->daddr, t1);
914 }
915#endif
916
917 memset(&fl6, 0, sizeof(fl6));
918 fl6.daddr = ipv6_hdr(skb)->saddr;
919 fl6.saddr = ipv6_hdr(skb)->daddr;
920 fl6.flowlabel = label;
921
922 buff->ip_summed = CHECKSUM_PARTIAL;
923 buff->csum = 0;
924
925 __tcp_v6_send_check(buff, &fl6.saddr, &fl6.daddr);
926
927 fl6.flowi6_proto = IPPROTO_TCP;
928 if (rt6_need_strict(&fl6.daddr) && !oif)
929 fl6.flowi6_oif = tcp_v6_iif(skb);
930 else {
931 if (!oif && netif_index_is_l3_master(net, skb->skb_iif))
932 oif = skb->skb_iif;
933
934 fl6.flowi6_oif = oif;
935 }
936
937 if (sk) {
938 if (sk->sk_state == TCP_TIME_WAIT) {
939 mark = inet_twsk(sk)->tw_mark;
940 /* autoflowlabel relies on buff->hash */
941 skb_set_hash(buff, inet_twsk(sk)->tw_txhash,
942 PKT_HASH_TYPE_L4);
943 } else {
944 mark = sk->sk_mark;
945 }
946 buff->tstamp = tcp_transmit_time(sk);
947 }
948 fl6.flowi6_mark = IP6_REPLY_MARK(net, skb->mark) ?: mark;
949 fl6.fl6_dport = t1->dest;
950 fl6.fl6_sport = t1->source;
951 fl6.flowi6_uid = sock_net_uid(net, sk && sk_fullsock(sk) ? sk : NULL);
952 security_skb_classify_flow(skb, flowi6_to_flowi(&fl6));
953
954 /* Pass a socket to ip6_dst_lookup either it is for RST
955 * Underlying function will use this to retrieve the network
956 * namespace
957 */
958 dst = ip6_dst_lookup_flow(sock_net(ctl_sk), ctl_sk, &fl6, NULL);
959 if (!IS_ERR(dst)) {
960 skb_dst_set(buff, dst);
961 ip6_xmit(ctl_sk, buff, &fl6, fl6.flowi6_mark, NULL, tclass,
962 priority);
963 TCP_INC_STATS(net, TCP_MIB_OUTSEGS);
964 if (rst)
965 TCP_INC_STATS(net, TCP_MIB_OUTRSTS);
966 return;
967 }
968
969 kfree_skb(buff);
970}
971
972static void tcp_v6_send_reset(const struct sock *sk, struct sk_buff *skb)
973{
974 const struct tcphdr *th = tcp_hdr(skb);
975 struct ipv6hdr *ipv6h = ipv6_hdr(skb);
976 u32 seq = 0, ack_seq = 0;
977 struct tcp_md5sig_key *key = NULL;
978#ifdef CONFIG_TCP_MD5SIG
979 const __u8 *hash_location = NULL;
980 unsigned char newhash[16];
981 int genhash;
982 struct sock *sk1 = NULL;
983#endif
984 __be32 label = 0;
985 u32 priority = 0;
986 struct net *net;
987 int oif = 0;
988
989 if (th->rst)
990 return;
991
992 /* If sk not NULL, it means we did a successful lookup and incoming
993 * route had to be correct. prequeue might have dropped our dst.
994 */
995 if (!sk && !ipv6_unicast_destination(skb))
996 return;
997
998 net = sk ? sock_net(sk) : dev_net(skb_dst(skb)->dev);
999#ifdef CONFIG_TCP_MD5SIG
1000 rcu_read_lock();
1001 hash_location = tcp_parse_md5sig_option(th);
1002 if (sk && sk_fullsock(sk)) {
1003 int l3index;
1004
1005 /* sdif set, means packet ingressed via a device
1006 * in an L3 domain and inet_iif is set to it.
1007 */
1008 l3index = tcp_v6_sdif(skb) ? tcp_v6_iif_l3_slave(skb) : 0;
1009 key = tcp_v6_md5_do_lookup(sk, &ipv6h->saddr, l3index);
1010 } else if (hash_location) {
1011 int dif = tcp_v6_iif_l3_slave(skb);
1012 int sdif = tcp_v6_sdif(skb);
1013 int l3index;
1014
1015 /*
1016 * active side is lost. Try to find listening socket through
1017 * source port, and then find md5 key through listening socket.
1018 * we are not loose security here:
1019 * Incoming packet is checked with md5 hash with finding key,
1020 * no RST generated if md5 hash doesn't match.
1021 */
1022 sk1 = inet6_lookup_listener(net,
1023 &tcp_hashinfo, NULL, 0,
1024 &ipv6h->saddr,
1025 th->source, &ipv6h->daddr,
1026 ntohs(th->source), dif, sdif);
1027 if (!sk1)
1028 goto out;
1029
1030 /* sdif set, means packet ingressed via a device
1031 * in an L3 domain and dif is set to it.
1032 */
1033 l3index = tcp_v6_sdif(skb) ? dif : 0;
1034
1035 key = tcp_v6_md5_do_lookup(sk1, &ipv6h->saddr, l3index);
1036 if (!key)
1037 goto out;
1038
1039 genhash = tcp_v6_md5_hash_skb(newhash, key, NULL, skb);
1040 if (genhash || memcmp(hash_location, newhash, 16) != 0)
1041 goto out;
1042 }
1043#endif
1044
1045 if (th->ack)
1046 seq = ntohl(th->ack_seq);
1047 else
1048 ack_seq = ntohl(th->seq) + th->syn + th->fin + skb->len -
1049 (th->doff << 2);
1050
1051 if (sk) {
1052 oif = sk->sk_bound_dev_if;
1053 if (sk_fullsock(sk)) {
1054 const struct ipv6_pinfo *np = tcp_inet6_sk(sk);
1055
1056 trace_tcp_send_reset(sk, skb);
1057 if (np->repflow)
1058 label = ip6_flowlabel(ipv6h);
1059 priority = sk->sk_priority;
1060 }
1061 if (sk->sk_state == TCP_TIME_WAIT) {
1062 label = cpu_to_be32(inet_twsk(sk)->tw_flowlabel);
1063 priority = inet_twsk(sk)->tw_priority;
1064 }
1065 } else {
1066 if (net->ipv6.sysctl.flowlabel_reflect & FLOWLABEL_REFLECT_TCP_RESET)
1067 label = ip6_flowlabel(ipv6h);
1068 }
1069
1070 tcp_v6_send_response(sk, skb, seq, ack_seq, 0, 0, 0, oif, key, 1, 0,
1071 label, priority);
1072
1073#ifdef CONFIG_TCP_MD5SIG
1074out:
1075 rcu_read_unlock();
1076#endif
1077}
1078
1079static void tcp_v6_send_ack(const struct sock *sk, struct sk_buff *skb, u32 seq,
1080 u32 ack, u32 win, u32 tsval, u32 tsecr, int oif,
1081 struct tcp_md5sig_key *key, u8 tclass,
1082 __be32 label, u32 priority)
1083{
1084 tcp_v6_send_response(sk, skb, seq, ack, win, tsval, tsecr, oif, key, 0,
1085 tclass, label, priority);
1086}
1087
1088static void tcp_v6_timewait_ack(struct sock *sk, struct sk_buff *skb)
1089{
1090 struct inet_timewait_sock *tw = inet_twsk(sk);
1091 struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
1092
1093 tcp_v6_send_ack(sk, skb, tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
1094 tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
1095 tcp_time_stamp_raw() + tcptw->tw_ts_offset,
1096 tcptw->tw_ts_recent, tw->tw_bound_dev_if, tcp_twsk_md5_key(tcptw),
1097 tw->tw_tclass, cpu_to_be32(tw->tw_flowlabel), tw->tw_priority);
1098
1099 inet_twsk_put(tw);
1100}
1101
1102static void tcp_v6_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb,
1103 struct request_sock *req)
1104{
1105 int l3index;
1106
1107 l3index = tcp_v6_sdif(skb) ? tcp_v6_iif_l3_slave(skb) : 0;
1108
1109 /* sk->sk_state == TCP_LISTEN -> for regular TCP_SYN_RECV
1110 * sk->sk_state == TCP_SYN_RECV -> for Fast Open.
1111 */
1112 /* RFC 7323 2.3
1113 * The window field (SEG.WND) of every outgoing segment, with the
1114 * exception of <SYN> segments, MUST be right-shifted by
1115 * Rcv.Wind.Shift bits:
1116 */
1117 tcp_v6_send_ack(sk, skb, (sk->sk_state == TCP_LISTEN) ?
1118 tcp_rsk(req)->snt_isn + 1 : tcp_sk(sk)->snd_nxt,
1119 tcp_rsk(req)->rcv_nxt,
1120 req->rsk_rcv_wnd >> inet_rsk(req)->rcv_wscale,
1121 tcp_time_stamp_raw() + tcp_rsk(req)->ts_off,
1122 req->ts_recent, sk->sk_bound_dev_if,
1123 tcp_v6_md5_do_lookup(sk, &ipv6_hdr(skb)->saddr, l3index),
1124 0, 0, sk->sk_priority);
1125}
1126
1127
1128static struct sock *tcp_v6_cookie_check(struct sock *sk, struct sk_buff *skb)
1129{
1130#ifdef CONFIG_SYN_COOKIES
1131 const struct tcphdr *th = tcp_hdr(skb);
1132
1133 if (!th->syn)
1134 sk = cookie_v6_check(sk, skb);
1135#endif
1136 return sk;
1137}
1138
1139u16 tcp_v6_get_syncookie(struct sock *sk, struct ipv6hdr *iph,
1140 struct tcphdr *th, u32 *cookie)
1141{
1142 u16 mss = 0;
1143#ifdef CONFIG_SYN_COOKIES
1144 mss = tcp_get_syncookie_mss(&tcp6_request_sock_ops,
1145 &tcp_request_sock_ipv6_ops, sk, th);
1146 if (mss) {
1147 *cookie = __cookie_v6_init_sequence(iph, th, &mss);
1148 tcp_synq_overflow(sk);
1149 }
1150#endif
1151 return mss;
1152}
1153
1154static int tcp_v6_conn_request(struct sock *sk, struct sk_buff *skb)
1155{
1156 if (skb->protocol == htons(ETH_P_IP))
1157 return tcp_v4_conn_request(sk, skb);
1158
1159 if (!ipv6_unicast_destination(skb))
1160 goto drop;
1161
1162 return tcp_conn_request(&tcp6_request_sock_ops,
1163 &tcp_request_sock_ipv6_ops, sk, skb);
1164
1165drop:
1166 tcp_listendrop(sk);
1167 return 0; /* don't send reset */
1168}
1169
1170static void tcp_v6_restore_cb(struct sk_buff *skb)
1171{
1172 /* We need to move header back to the beginning if xfrm6_policy_check()
1173 * and tcp_v6_fill_cb() are going to be called again.
1174 * ip6_datagram_recv_specific_ctl() also expects IP6CB to be there.
1175 */
1176 memmove(IP6CB(skb), &TCP_SKB_CB(skb)->header.h6,
1177 sizeof(struct inet6_skb_parm));
1178}
1179
1180static struct sock *tcp_v6_syn_recv_sock(const struct sock *sk, struct sk_buff *skb,
1181 struct request_sock *req,
1182 struct dst_entry *dst,
1183 struct request_sock *req_unhash,
1184 bool *own_req)
1185{
1186 struct inet_request_sock *ireq;
1187 struct ipv6_pinfo *newnp;
1188 const struct ipv6_pinfo *np = tcp_inet6_sk(sk);
1189 struct ipv6_txoptions *opt;
1190 struct inet_sock *newinet;
1191 struct tcp_sock *newtp;
1192 struct sock *newsk;
1193#ifdef CONFIG_TCP_MD5SIG
1194 struct tcp_md5sig_key *key;
1195 int l3index;
1196#endif
1197 struct flowi6 fl6;
1198
1199 if (skb->protocol == htons(ETH_P_IP)) {
1200 /*
1201 * v6 mapped
1202 */
1203
1204 newsk = tcp_v4_syn_recv_sock(sk, skb, req, dst,
1205 req_unhash, own_req);
1206
1207 if (!newsk)
1208 return NULL;
1209
1210 inet_sk(newsk)->pinet6 = tcp_inet6_sk(newsk);
1211
1212 newinet = inet_sk(newsk);
1213 newnp = tcp_inet6_sk(newsk);
1214 newtp = tcp_sk(newsk);
1215
1216 memcpy(newnp, np, sizeof(struct ipv6_pinfo));
1217
1218 newnp->saddr = newsk->sk_v6_rcv_saddr;
1219
1220 inet_csk(newsk)->icsk_af_ops = &ipv6_mapped;
1221 if (sk_is_mptcp(newsk))
1222 mptcpv6_handle_mapped(newsk, true);
1223 newsk->sk_backlog_rcv = tcp_v4_do_rcv;
1224#ifdef CONFIG_TCP_MD5SIG
1225 newtp->af_specific = &tcp_sock_ipv6_mapped_specific;
1226#endif
1227
1228 newnp->ipv6_mc_list = NULL;
1229 newnp->ipv6_ac_list = NULL;
1230 newnp->ipv6_fl_list = NULL;
1231 newnp->pktoptions = NULL;
1232 newnp->opt = NULL;
1233 newnp->mcast_oif = inet_iif(skb);
1234 newnp->mcast_hops = ip_hdr(skb)->ttl;
1235 newnp->rcv_flowinfo = 0;
1236 if (np->repflow)
1237 newnp->flow_label = 0;
1238
1239 /*
1240 * No need to charge this sock to the relevant IPv6 refcnt debug socks count
1241 * here, tcp_create_openreq_child now does this for us, see the comment in
1242 * that function for the gory details. -acme
1243 */
1244
1245 /* It is tricky place. Until this moment IPv4 tcp
1246 worked with IPv6 icsk.icsk_af_ops.
1247 Sync it now.
1248 */
1249 tcp_sync_mss(newsk, inet_csk(newsk)->icsk_pmtu_cookie);
1250
1251 return newsk;
1252 }
1253
1254 ireq = inet_rsk(req);
1255
1256 if (sk_acceptq_is_full(sk))
1257 goto out_overflow;
1258
1259 if (!dst) {
1260 dst = inet6_csk_route_req(sk, &fl6, req, IPPROTO_TCP);
1261 if (!dst)
1262 goto out;
1263 }
1264
1265 newsk = tcp_create_openreq_child(sk, req, skb);
1266 if (!newsk)
1267 goto out_nonewsk;
1268
1269 /*
1270 * No need to charge this sock to the relevant IPv6 refcnt debug socks
1271 * count here, tcp_create_openreq_child now does this for us, see the
1272 * comment in that function for the gory details. -acme
1273 */
1274
1275 newsk->sk_gso_type = SKB_GSO_TCPV6;
1276 ip6_dst_store(newsk, dst, NULL, NULL);
1277 inet6_sk_rx_dst_set(newsk, skb);
1278
1279 inet_sk(newsk)->pinet6 = tcp_inet6_sk(newsk);
1280
1281 newtp = tcp_sk(newsk);
1282 newinet = inet_sk(newsk);
1283 newnp = tcp_inet6_sk(newsk);
1284
1285 memcpy(newnp, np, sizeof(struct ipv6_pinfo));
1286
1287 newsk->sk_v6_daddr = ireq->ir_v6_rmt_addr;
1288 newnp->saddr = ireq->ir_v6_loc_addr;
1289 newsk->sk_v6_rcv_saddr = ireq->ir_v6_loc_addr;
1290 newsk->sk_bound_dev_if = ireq->ir_iif;
1291
1292 /* Now IPv6 options...
1293
1294 First: no IPv4 options.
1295 */
1296 newinet->inet_opt = NULL;
1297 newnp->ipv6_mc_list = NULL;
1298 newnp->ipv6_ac_list = NULL;
1299 newnp->ipv6_fl_list = NULL;
1300
1301 /* Clone RX bits */
1302 newnp->rxopt.all = np->rxopt.all;
1303
1304 newnp->pktoptions = NULL;
1305 newnp->opt = NULL;
1306 newnp->mcast_oif = tcp_v6_iif(skb);
1307 newnp->mcast_hops = ipv6_hdr(skb)->hop_limit;
1308 newnp->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(skb));
1309 if (np->repflow)
1310 newnp->flow_label = ip6_flowlabel(ipv6_hdr(skb));
1311
1312 /* Clone native IPv6 options from listening socket (if any)
1313
1314 Yes, keeping reference count would be much more clever,
1315 but we make one more one thing there: reattach optmem
1316 to newsk.
1317 */
1318 opt = ireq->ipv6_opt;
1319 if (!opt)
1320 opt = rcu_dereference(np->opt);
1321 if (opt) {
1322 opt = ipv6_dup_options(newsk, opt);
1323 RCU_INIT_POINTER(newnp->opt, opt);
1324 }
1325 inet_csk(newsk)->icsk_ext_hdr_len = 0;
1326 if (opt)
1327 inet_csk(newsk)->icsk_ext_hdr_len = opt->opt_nflen +
1328 opt->opt_flen;
1329
1330 tcp_ca_openreq_child(newsk, dst);
1331
1332 tcp_sync_mss(newsk, dst_mtu(dst));
1333 newtp->advmss = tcp_mss_clamp(tcp_sk(sk), dst_metric_advmss(dst));
1334
1335 tcp_initialize_rcv_mss(newsk);
1336
1337 newinet->inet_daddr = newinet->inet_saddr = LOOPBACK4_IPV6;
1338 newinet->inet_rcv_saddr = LOOPBACK4_IPV6;
1339
1340#ifdef CONFIG_TCP_MD5SIG
1341 l3index = l3mdev_master_ifindex_by_index(sock_net(sk), ireq->ir_iif);
1342
1343 /* Copy over the MD5 key from the original socket */
1344 key = tcp_v6_md5_do_lookup(sk, &newsk->sk_v6_daddr, l3index);
1345 if (key) {
1346 /* We're using one, so create a matching key
1347 * on the newsk structure. If we fail to get
1348 * memory, then we end up not copying the key
1349 * across. Shucks.
1350 */
1351 tcp_md5_do_add(newsk, (union tcp_md5_addr *)&newsk->sk_v6_daddr,
1352 AF_INET6, 128, l3index, key->key, key->keylen,
1353 sk_gfp_mask(sk, GFP_ATOMIC));
1354 }
1355#endif
1356
1357 if (__inet_inherit_port(sk, newsk) < 0) {
1358 inet_csk_prepare_forced_close(newsk);
1359 tcp_done(newsk);
1360 goto out;
1361 }
1362 *own_req = inet_ehash_nolisten(newsk, req_to_sk(req_unhash));
1363 if (*own_req) {
1364 tcp_move_syn(newtp, req);
1365
1366 /* Clone pktoptions received with SYN, if we own the req */
1367 if (ireq->pktopts) {
1368 newnp->pktoptions = skb_clone(ireq->pktopts,
1369 sk_gfp_mask(sk, GFP_ATOMIC));
1370 consume_skb(ireq->pktopts);
1371 ireq->pktopts = NULL;
1372 if (newnp->pktoptions) {
1373 tcp_v6_restore_cb(newnp->pktoptions);
1374 skb_set_owner_r(newnp->pktoptions, newsk);
1375 }
1376 }
1377 }
1378
1379 return newsk;
1380
1381out_overflow:
1382 __NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
1383out_nonewsk:
1384 dst_release(dst);
1385out:
1386 tcp_listendrop(sk);
1387 return NULL;
1388}
1389
1390/* The socket must have it's spinlock held when we get
1391 * here, unless it is a TCP_LISTEN socket.
1392 *
1393 * We have a potential double-lock case here, so even when
1394 * doing backlog processing we use the BH locking scheme.
1395 * This is because we cannot sleep with the original spinlock
1396 * held.
1397 */
1398static int tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb)
1399{
1400 struct ipv6_pinfo *np = tcp_inet6_sk(sk);
1401 struct sk_buff *opt_skb = NULL;
1402 struct tcp_sock *tp;
1403
1404 /* Imagine: socket is IPv6. IPv4 packet arrives,
1405 goes to IPv4 receive handler and backlogged.
1406 From backlog it always goes here. Kerboom...
1407 Fortunately, tcp_rcv_established and rcv_established
1408 handle them correctly, but it is not case with
1409 tcp_v6_hnd_req and tcp_v6_send_reset(). --ANK
1410 */
1411
1412 if (skb->protocol == htons(ETH_P_IP))
1413 return tcp_v4_do_rcv(sk, skb);
1414
1415 /*
1416 * socket locking is here for SMP purposes as backlog rcv
1417 * is currently called with bh processing disabled.
1418 */
1419
1420 /* Do Stevens' IPV6_PKTOPTIONS.
1421
1422 Yes, guys, it is the only place in our code, where we
1423 may make it not affecting IPv4.
1424 The rest of code is protocol independent,
1425 and I do not like idea to uglify IPv4.
1426
1427 Actually, all the idea behind IPV6_PKTOPTIONS
1428 looks not very well thought. For now we latch
1429 options, received in the last packet, enqueued
1430 by tcp. Feel free to propose better solution.
1431 --ANK (980728)
1432 */
1433 if (np->rxopt.all)
1434 opt_skb = skb_clone(skb, sk_gfp_mask(sk, GFP_ATOMIC));
1435
1436 if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
1437 struct dst_entry *dst = sk->sk_rx_dst;
1438
1439 sock_rps_save_rxhash(sk, skb);
1440 sk_mark_napi_id(sk, skb);
1441 if (dst) {
1442 if (inet_sk(sk)->rx_dst_ifindex != skb->skb_iif ||
1443 dst->ops->check(dst, np->rx_dst_cookie) == NULL) {
1444 dst_release(dst);
1445 sk->sk_rx_dst = NULL;
1446 }
1447 }
1448
1449 tcp_rcv_established(sk, skb);
1450 if (opt_skb)
1451 goto ipv6_pktoptions;
1452 return 0;
1453 }
1454
1455 if (tcp_checksum_complete(skb))
1456 goto csum_err;
1457
1458 if (sk->sk_state == TCP_LISTEN) {
1459 struct sock *nsk = tcp_v6_cookie_check(sk, skb);
1460
1461 if (!nsk)
1462 goto discard;
1463
1464 if (nsk != sk) {
1465 if (tcp_child_process(sk, nsk, skb))
1466 goto reset;
1467 if (opt_skb)
1468 __kfree_skb(opt_skb);
1469 return 0;
1470 }
1471 } else
1472 sock_rps_save_rxhash(sk, skb);
1473
1474 if (tcp_rcv_state_process(sk, skb))
1475 goto reset;
1476 if (opt_skb)
1477 goto ipv6_pktoptions;
1478 return 0;
1479
1480reset:
1481 tcp_v6_send_reset(sk, skb);
1482discard:
1483 if (opt_skb)
1484 __kfree_skb(opt_skb);
1485 kfree_skb(skb);
1486 return 0;
1487csum_err:
1488 TCP_INC_STATS(sock_net(sk), TCP_MIB_CSUMERRORS);
1489 TCP_INC_STATS(sock_net(sk), TCP_MIB_INERRS);
1490 goto discard;
1491
1492
1493ipv6_pktoptions:
1494 /* Do you ask, what is it?
1495
1496 1. skb was enqueued by tcp.
1497 2. skb is added to tail of read queue, rather than out of order.
1498 3. socket is not in passive state.
1499 4. Finally, it really contains options, which user wants to receive.
1500 */
1501 tp = tcp_sk(sk);
1502 if (TCP_SKB_CB(opt_skb)->end_seq == tp->rcv_nxt &&
1503 !((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN))) {
1504 if (np->rxopt.bits.rxinfo || np->rxopt.bits.rxoinfo)
1505 np->mcast_oif = tcp_v6_iif(opt_skb);
1506 if (np->rxopt.bits.rxhlim || np->rxopt.bits.rxohlim)
1507 np->mcast_hops = ipv6_hdr(opt_skb)->hop_limit;
1508 if (np->rxopt.bits.rxflow || np->rxopt.bits.rxtclass)
1509 np->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(opt_skb));
1510 if (np->repflow)
1511 np->flow_label = ip6_flowlabel(ipv6_hdr(opt_skb));
1512 if (ipv6_opt_accepted(sk, opt_skb, &TCP_SKB_CB(opt_skb)->header.h6)) {
1513 skb_set_owner_r(opt_skb, sk);
1514 tcp_v6_restore_cb(opt_skb);
1515 opt_skb = xchg(&np->pktoptions, opt_skb);
1516 } else {
1517 __kfree_skb(opt_skb);
1518 opt_skb = xchg(&np->pktoptions, NULL);
1519 }
1520 }
1521
1522 kfree_skb(opt_skb);
1523 return 0;
1524}
1525
1526static void tcp_v6_fill_cb(struct sk_buff *skb, const struct ipv6hdr *hdr,
1527 const struct tcphdr *th)
1528{
1529 /* This is tricky: we move IP6CB at its correct location into
1530 * TCP_SKB_CB(). It must be done after xfrm6_policy_check(), because
1531 * _decode_session6() uses IP6CB().
1532 * barrier() makes sure compiler won't play aliasing games.
1533 */
1534 memmove(&TCP_SKB_CB(skb)->header.h6, IP6CB(skb),
1535 sizeof(struct inet6_skb_parm));
1536 barrier();
1537
1538 TCP_SKB_CB(skb)->seq = ntohl(th->seq);
1539 TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
1540 skb->len - th->doff*4);
1541 TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
1542 TCP_SKB_CB(skb)->tcp_flags = tcp_flag_byte(th);
1543 TCP_SKB_CB(skb)->tcp_tw_isn = 0;
1544 TCP_SKB_CB(skb)->ip_dsfield = ipv6_get_dsfield(hdr);
1545 TCP_SKB_CB(skb)->sacked = 0;
1546 TCP_SKB_CB(skb)->has_rxtstamp =
1547 skb->tstamp || skb_hwtstamps(skb)->hwtstamp;
1548}
1549
1550INDIRECT_CALLABLE_SCOPE int tcp_v6_rcv(struct sk_buff *skb)
1551{
1552 struct sk_buff *skb_to_free;
1553 int sdif = inet6_sdif(skb);
1554 int dif = inet6_iif(skb);
1555 const struct tcphdr *th;
1556 const struct ipv6hdr *hdr;
1557 bool refcounted;
1558 struct sock *sk;
1559 int ret;
1560 struct net *net = dev_net(skb->dev);
1561
1562 if (skb->pkt_type != PACKET_HOST)
1563 goto discard_it;
1564
1565 /*
1566 * Count it even if it's bad.
1567 */
1568 __TCP_INC_STATS(net, TCP_MIB_INSEGS);
1569
1570 if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
1571 goto discard_it;
1572
1573 th = (const struct tcphdr *)skb->data;
1574
1575 if (unlikely(th->doff < sizeof(struct tcphdr)/4))
1576 goto bad_packet;
1577 if (!pskb_may_pull(skb, th->doff*4))
1578 goto discard_it;
1579
1580 if (skb_checksum_init(skb, IPPROTO_TCP, ip6_compute_pseudo))
1581 goto csum_error;
1582
1583 th = (const struct tcphdr *)skb->data;
1584 hdr = ipv6_hdr(skb);
1585
1586lookup:
1587 sk = __inet6_lookup_skb(&tcp_hashinfo, skb, __tcp_hdrlen(th),
1588 th->source, th->dest, inet6_iif(skb), sdif,
1589 &refcounted);
1590 if (!sk)
1591 goto no_tcp_socket;
1592
1593process:
1594 if (sk->sk_state == TCP_TIME_WAIT)
1595 goto do_time_wait;
1596
1597 if (sk->sk_state == TCP_NEW_SYN_RECV) {
1598 struct request_sock *req = inet_reqsk(sk);
1599 bool req_stolen = false;
1600 struct sock *nsk;
1601
1602 sk = req->rsk_listener;
1603 if (tcp_v6_inbound_md5_hash(sk, skb, dif, sdif)) {
1604 sk_drops_add(sk, skb);
1605 reqsk_put(req);
1606 goto discard_it;
1607 }
1608 if (tcp_checksum_complete(skb)) {
1609 reqsk_put(req);
1610 goto csum_error;
1611 }
1612 if (unlikely(sk->sk_state != TCP_LISTEN)) {
1613 inet_csk_reqsk_queue_drop_and_put(sk, req);
1614 goto lookup;
1615 }
1616 sock_hold(sk);
1617 refcounted = true;
1618 nsk = NULL;
1619 if (!tcp_filter(sk, skb)) {
1620 th = (const struct tcphdr *)skb->data;
1621 hdr = ipv6_hdr(skb);
1622 tcp_v6_fill_cb(skb, hdr, th);
1623 nsk = tcp_check_req(sk, skb, req, false, &req_stolen);
1624 }
1625 if (!nsk) {
1626 reqsk_put(req);
1627 if (req_stolen) {
1628 /* Another cpu got exclusive access to req
1629 * and created a full blown socket.
1630 * Try to feed this packet to this socket
1631 * instead of discarding it.
1632 */
1633 tcp_v6_restore_cb(skb);
1634 sock_put(sk);
1635 goto lookup;
1636 }
1637 goto discard_and_relse;
1638 }
1639 if (nsk == sk) {
1640 reqsk_put(req);
1641 tcp_v6_restore_cb(skb);
1642 } else if (tcp_child_process(sk, nsk, skb)) {
1643 tcp_v6_send_reset(nsk, skb);
1644 goto discard_and_relse;
1645 } else {
1646 sock_put(sk);
1647 return 0;
1648 }
1649 }
1650 if (hdr->hop_limit < tcp_inet6_sk(sk)->min_hopcount) {
1651 __NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP);
1652 goto discard_and_relse;
1653 }
1654
1655 if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb))
1656 goto discard_and_relse;
1657
1658 if (tcp_v6_inbound_md5_hash(sk, skb, dif, sdif))
1659 goto discard_and_relse;
1660
1661 if (tcp_filter(sk, skb))
1662 goto discard_and_relse;
1663 th = (const struct tcphdr *)skb->data;
1664 hdr = ipv6_hdr(skb);
1665 tcp_v6_fill_cb(skb, hdr, th);
1666
1667 skb->dev = NULL;
1668
1669 if (sk->sk_state == TCP_LISTEN) {
1670 ret = tcp_v6_do_rcv(sk, skb);
1671 goto put_and_return;
1672 }
1673
1674 sk_incoming_cpu_update(sk);
1675
1676 bh_lock_sock_nested(sk);
1677 tcp_segs_in(tcp_sk(sk), skb);
1678 ret = 0;
1679 if (!sock_owned_by_user(sk)) {
1680 skb_to_free = sk->sk_rx_skb_cache;
1681 sk->sk_rx_skb_cache = NULL;
1682 ret = tcp_v6_do_rcv(sk, skb);
1683 } else {
1684 if (tcp_add_backlog(sk, skb))
1685 goto discard_and_relse;
1686 skb_to_free = NULL;
1687 }
1688 bh_unlock_sock(sk);
1689 if (skb_to_free)
1690 __kfree_skb(skb_to_free);
1691put_and_return:
1692 if (refcounted)
1693 sock_put(sk);
1694 return ret ? -1 : 0;
1695
1696no_tcp_socket:
1697 if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb))
1698 goto discard_it;
1699
1700 tcp_v6_fill_cb(skb, hdr, th);
1701
1702 if (tcp_checksum_complete(skb)) {
1703csum_error:
1704 __TCP_INC_STATS(net, TCP_MIB_CSUMERRORS);
1705bad_packet:
1706 __TCP_INC_STATS(net, TCP_MIB_INERRS);
1707 } else {
1708 tcp_v6_send_reset(NULL, skb);
1709 }
1710
1711discard_it:
1712 kfree_skb(skb);
1713 return 0;
1714
1715discard_and_relse:
1716 sk_drops_add(sk, skb);
1717 if (refcounted)
1718 sock_put(sk);
1719 goto discard_it;
1720
1721do_time_wait:
1722 if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
1723 inet_twsk_put(inet_twsk(sk));
1724 goto discard_it;
1725 }
1726
1727 tcp_v6_fill_cb(skb, hdr, th);
1728
1729 if (tcp_checksum_complete(skb)) {
1730 inet_twsk_put(inet_twsk(sk));
1731 goto csum_error;
1732 }
1733
1734 switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) {
1735 case TCP_TW_SYN:
1736 {
1737 struct sock *sk2;
1738
1739 sk2 = inet6_lookup_listener(dev_net(skb->dev), &tcp_hashinfo,
1740 skb, __tcp_hdrlen(th),
1741 &ipv6_hdr(skb)->saddr, th->source,
1742 &ipv6_hdr(skb)->daddr,
1743 ntohs(th->dest),
1744 tcp_v6_iif_l3_slave(skb),
1745 sdif);
1746 if (sk2) {
1747 struct inet_timewait_sock *tw = inet_twsk(sk);
1748 inet_twsk_deschedule_put(tw);
1749 sk = sk2;
1750 tcp_v6_restore_cb(skb);
1751 refcounted = false;
1752 goto process;
1753 }
1754 }
1755 /* to ACK */
1756 fallthrough;
1757 case TCP_TW_ACK:
1758 tcp_v6_timewait_ack(sk, skb);
1759 break;
1760 case TCP_TW_RST:
1761 tcp_v6_send_reset(sk, skb);
1762 inet_twsk_deschedule_put(inet_twsk(sk));
1763 goto discard_it;
1764 case TCP_TW_SUCCESS:
1765 ;
1766 }
1767 goto discard_it;
1768}
1769
1770INDIRECT_CALLABLE_SCOPE void tcp_v6_early_demux(struct sk_buff *skb)
1771{
1772 const struct ipv6hdr *hdr;
1773 const struct tcphdr *th;
1774 struct sock *sk;
1775
1776 if (skb->pkt_type != PACKET_HOST)
1777 return;
1778
1779 if (!pskb_may_pull(skb, skb_transport_offset(skb) + sizeof(struct tcphdr)))
1780 return;
1781
1782 hdr = ipv6_hdr(skb);
1783 th = tcp_hdr(skb);
1784
1785 if (th->doff < sizeof(struct tcphdr) / 4)
1786 return;
1787
1788 /* Note : We use inet6_iif() here, not tcp_v6_iif() */
1789 sk = __inet6_lookup_established(dev_net(skb->dev), &tcp_hashinfo,
1790 &hdr->saddr, th->source,
1791 &hdr->daddr, ntohs(th->dest),
1792 inet6_iif(skb), inet6_sdif(skb));
1793 if (sk) {
1794 skb->sk = sk;
1795 skb->destructor = sock_edemux;
1796 if (sk_fullsock(sk)) {
1797 struct dst_entry *dst = READ_ONCE(sk->sk_rx_dst);
1798
1799 if (dst)
1800 dst = dst_check(dst, tcp_inet6_sk(sk)->rx_dst_cookie);
1801 if (dst &&
1802 inet_sk(sk)->rx_dst_ifindex == skb->skb_iif)
1803 skb_dst_set_noref(skb, dst);
1804 }
1805 }
1806}
1807
1808static struct timewait_sock_ops tcp6_timewait_sock_ops = {
1809 .twsk_obj_size = sizeof(struct tcp6_timewait_sock),
1810 .twsk_unique = tcp_twsk_unique,
1811 .twsk_destructor = tcp_twsk_destructor,
1812};
1813
1814INDIRECT_CALLABLE_SCOPE void tcp_v6_send_check(struct sock *sk, struct sk_buff *skb)
1815{
1816 struct ipv6_pinfo *np = inet6_sk(sk);
1817
1818 __tcp_v6_send_check(skb, &np->saddr, &sk->sk_v6_daddr);
1819}
1820
1821const struct inet_connection_sock_af_ops ipv6_specific = {
1822 .queue_xmit = inet6_csk_xmit,
1823 .send_check = tcp_v6_send_check,
1824 .rebuild_header = inet6_sk_rebuild_header,
1825 .sk_rx_dst_set = inet6_sk_rx_dst_set,
1826 .conn_request = tcp_v6_conn_request,
1827 .syn_recv_sock = tcp_v6_syn_recv_sock,
1828 .net_header_len = sizeof(struct ipv6hdr),
1829 .net_frag_header_len = sizeof(struct frag_hdr),
1830 .setsockopt = ipv6_setsockopt,
1831 .getsockopt = ipv6_getsockopt,
1832 .addr2sockaddr = inet6_csk_addr2sockaddr,
1833 .sockaddr_len = sizeof(struct sockaddr_in6),
1834 .mtu_reduced = tcp_v6_mtu_reduced,
1835};
1836
1837#ifdef CONFIG_TCP_MD5SIG
1838static const struct tcp_sock_af_ops tcp_sock_ipv6_specific = {
1839 .md5_lookup = tcp_v6_md5_lookup,
1840 .calc_md5_hash = tcp_v6_md5_hash_skb,
1841 .md5_parse = tcp_v6_parse_md5_keys,
1842};
1843#endif
1844
1845/*
1846 * TCP over IPv4 via INET6 API
1847 */
1848static const struct inet_connection_sock_af_ops ipv6_mapped = {
1849 .queue_xmit = ip_queue_xmit,
1850 .send_check = tcp_v4_send_check,
1851 .rebuild_header = inet_sk_rebuild_header,
1852 .sk_rx_dst_set = inet_sk_rx_dst_set,
1853 .conn_request = tcp_v6_conn_request,
1854 .syn_recv_sock = tcp_v6_syn_recv_sock,
1855 .net_header_len = sizeof(struct iphdr),
1856 .setsockopt = ipv6_setsockopt,
1857 .getsockopt = ipv6_getsockopt,
1858 .addr2sockaddr = inet6_csk_addr2sockaddr,
1859 .sockaddr_len = sizeof(struct sockaddr_in6),
1860 .mtu_reduced = tcp_v4_mtu_reduced,
1861};
1862
1863#ifdef CONFIG_TCP_MD5SIG
1864static const struct tcp_sock_af_ops tcp_sock_ipv6_mapped_specific = {
1865 .md5_lookup = tcp_v4_md5_lookup,
1866 .calc_md5_hash = tcp_v4_md5_hash_skb,
1867 .md5_parse = tcp_v6_parse_md5_keys,
1868};
1869#endif
1870
1871/* NOTE: A lot of things set to zero explicitly by call to
1872 * sk_alloc() so need not be done here.
1873 */
1874static int tcp_v6_init_sock(struct sock *sk)
1875{
1876 struct inet_connection_sock *icsk = inet_csk(sk);
1877
1878 tcp_init_sock(sk);
1879
1880 icsk->icsk_af_ops = &ipv6_specific;
1881
1882#ifdef CONFIG_TCP_MD5SIG
1883 tcp_sk(sk)->af_specific = &tcp_sock_ipv6_specific;
1884#endif
1885
1886 return 0;
1887}
1888
1889static void tcp_v6_destroy_sock(struct sock *sk)
1890{
1891 tcp_v4_destroy_sock(sk);
1892 inet6_destroy_sock(sk);
1893}
1894
1895#ifdef CONFIG_PROC_FS
1896/* Proc filesystem TCPv6 sock list dumping. */
1897static void get_openreq6(struct seq_file *seq,
1898 const struct request_sock *req, int i)
1899{
1900 long ttd = req->rsk_timer.expires - jiffies;
1901 const struct in6_addr *src = &inet_rsk(req)->ir_v6_loc_addr;
1902 const struct in6_addr *dest = &inet_rsk(req)->ir_v6_rmt_addr;
1903
1904 if (ttd < 0)
1905 ttd = 0;
1906
1907 seq_printf(seq,
1908 "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
1909 "%02X %08X:%08X %02X:%08lX %08X %5u %8d %d %d %pK\n",
1910 i,
1911 src->s6_addr32[0], src->s6_addr32[1],
1912 src->s6_addr32[2], src->s6_addr32[3],
1913 inet_rsk(req)->ir_num,
1914 dest->s6_addr32[0], dest->s6_addr32[1],
1915 dest->s6_addr32[2], dest->s6_addr32[3],
1916 ntohs(inet_rsk(req)->ir_rmt_port),
1917 TCP_SYN_RECV,
1918 0, 0, /* could print option size, but that is af dependent. */
1919 1, /* timers active (only the expire timer) */
1920 jiffies_to_clock_t(ttd),
1921 req->num_timeout,
1922 from_kuid_munged(seq_user_ns(seq),
1923 sock_i_uid(req->rsk_listener)),
1924 0, /* non standard timer */
1925 0, /* open_requests have no inode */
1926 0, req);
1927}
1928
1929static void get_tcp6_sock(struct seq_file *seq, struct sock *sp, int i)
1930{
1931 const struct in6_addr *dest, *src;
1932 __u16 destp, srcp;
1933 int timer_active;
1934 unsigned long timer_expires;
1935 const struct inet_sock *inet = inet_sk(sp);
1936 const struct tcp_sock *tp = tcp_sk(sp);
1937 const struct inet_connection_sock *icsk = inet_csk(sp);
1938 const struct fastopen_queue *fastopenq = &icsk->icsk_accept_queue.fastopenq;
1939 int rx_queue;
1940 int state;
1941
1942 dest = &sp->sk_v6_daddr;
1943 src = &sp->sk_v6_rcv_saddr;
1944 destp = ntohs(inet->inet_dport);
1945 srcp = ntohs(inet->inet_sport);
1946
1947 if (icsk->icsk_pending == ICSK_TIME_RETRANS ||
1948 icsk->icsk_pending == ICSK_TIME_REO_TIMEOUT ||
1949 icsk->icsk_pending == ICSK_TIME_LOSS_PROBE) {
1950 timer_active = 1;
1951 timer_expires = icsk->icsk_timeout;
1952 } else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
1953 timer_active = 4;
1954 timer_expires = icsk->icsk_timeout;
1955 } else if (timer_pending(&sp->sk_timer)) {
1956 timer_active = 2;
1957 timer_expires = sp->sk_timer.expires;
1958 } else {
1959 timer_active = 0;
1960 timer_expires = jiffies;
1961 }
1962
1963 state = inet_sk_state_load(sp);
1964 if (state == TCP_LISTEN)
1965 rx_queue = READ_ONCE(sp->sk_ack_backlog);
1966 else
1967 /* Because we don't lock the socket,
1968 * we might find a transient negative value.
1969 */
1970 rx_queue = max_t(int, READ_ONCE(tp->rcv_nxt) -
1971 READ_ONCE(tp->copied_seq), 0);
1972
1973 seq_printf(seq,
1974 "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
1975 "%02X %08X:%08X %02X:%08lX %08X %5u %8d %lu %d %pK %lu %lu %u %u %d\n",
1976 i,
1977 src->s6_addr32[0], src->s6_addr32[1],
1978 src->s6_addr32[2], src->s6_addr32[3], srcp,
1979 dest->s6_addr32[0], dest->s6_addr32[1],
1980 dest->s6_addr32[2], dest->s6_addr32[3], destp,
1981 state,
1982 READ_ONCE(tp->write_seq) - tp->snd_una,
1983 rx_queue,
1984 timer_active,
1985 jiffies_delta_to_clock_t(timer_expires - jiffies),
1986 icsk->icsk_retransmits,
1987 from_kuid_munged(seq_user_ns(seq), sock_i_uid(sp)),
1988 icsk->icsk_probes_out,
1989 sock_i_ino(sp),
1990 refcount_read(&sp->sk_refcnt), sp,
1991 jiffies_to_clock_t(icsk->icsk_rto),
1992 jiffies_to_clock_t(icsk->icsk_ack.ato),
1993 (icsk->icsk_ack.quick << 1) | inet_csk_in_pingpong_mode(sp),
1994 tp->snd_cwnd,
1995 state == TCP_LISTEN ?
1996 fastopenq->max_qlen :
1997 (tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh)
1998 );
1999}
2000
2001static void get_timewait6_sock(struct seq_file *seq,
2002 struct inet_timewait_sock *tw, int i)
2003{
2004 long delta = tw->tw_timer.expires - jiffies;
2005 const struct in6_addr *dest, *src;
2006 __u16 destp, srcp;
2007
2008 dest = &tw->tw_v6_daddr;
2009 src = &tw->tw_v6_rcv_saddr;
2010 destp = ntohs(tw->tw_dport);
2011 srcp = ntohs(tw->tw_sport);
2012
2013 seq_printf(seq,
2014 "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
2015 "%02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK\n",
2016 i,
2017 src->s6_addr32[0], src->s6_addr32[1],
2018 src->s6_addr32[2], src->s6_addr32[3], srcp,
2019 dest->s6_addr32[0], dest->s6_addr32[1],
2020 dest->s6_addr32[2], dest->s6_addr32[3], destp,
2021 tw->tw_substate, 0, 0,
2022 3, jiffies_delta_to_clock_t(delta), 0, 0, 0, 0,
2023 refcount_read(&tw->tw_refcnt), tw);
2024}
2025
2026static int tcp6_seq_show(struct seq_file *seq, void *v)
2027{
2028 struct tcp_iter_state *st;
2029 struct sock *sk = v;
2030
2031 if (v == SEQ_START_TOKEN) {
2032 seq_puts(seq,
2033 " sl "
2034 "local_address "
2035 "remote_address "
2036 "st tx_queue rx_queue tr tm->when retrnsmt"
2037 " uid timeout inode\n");
2038 goto out;
2039 }
2040 st = seq->private;
2041
2042 if (sk->sk_state == TCP_TIME_WAIT)
2043 get_timewait6_sock(seq, v, st->num);
2044 else if (sk->sk_state == TCP_NEW_SYN_RECV)
2045 get_openreq6(seq, v, st->num);
2046 else
2047 get_tcp6_sock(seq, v, st->num);
2048out:
2049 return 0;
2050}
2051
2052static const struct seq_operations tcp6_seq_ops = {
2053 .show = tcp6_seq_show,
2054 .start = tcp_seq_start,
2055 .next = tcp_seq_next,
2056 .stop = tcp_seq_stop,
2057};
2058
2059static struct tcp_seq_afinfo tcp6_seq_afinfo = {
2060 .family = AF_INET6,
2061};
2062
2063int __net_init tcp6_proc_init(struct net *net)
2064{
2065 if (!proc_create_net_data("tcp6", 0444, net->proc_net, &tcp6_seq_ops,
2066 sizeof(struct tcp_iter_state), &tcp6_seq_afinfo))
2067 return -ENOMEM;
2068 return 0;
2069}
2070
2071void tcp6_proc_exit(struct net *net)
2072{
2073 remove_proc_entry("tcp6", net->proc_net);
2074}
2075#endif
2076
2077struct proto tcpv6_prot = {
2078 .name = "TCPv6",
2079 .owner = THIS_MODULE,
2080 .close = tcp_close,
2081 .pre_connect = tcp_v6_pre_connect,
2082 .connect = tcp_v6_connect,
2083 .disconnect = tcp_disconnect,
2084 .accept = inet_csk_accept,
2085 .ioctl = tcp_ioctl,
2086 .init = tcp_v6_init_sock,
2087 .destroy = tcp_v6_destroy_sock,
2088 .shutdown = tcp_shutdown,
2089 .setsockopt = tcp_setsockopt,
2090 .getsockopt = tcp_getsockopt,
2091 .keepalive = tcp_set_keepalive,
2092 .recvmsg = tcp_recvmsg,
2093 .sendmsg = tcp_sendmsg,
2094 .sendpage = tcp_sendpage,
2095 .backlog_rcv = tcp_v6_do_rcv,
2096 .release_cb = tcp_release_cb,
2097 .hash = inet6_hash,
2098 .unhash = inet_unhash,
2099 .get_port = inet_csk_get_port,
2100 .enter_memory_pressure = tcp_enter_memory_pressure,
2101 .leave_memory_pressure = tcp_leave_memory_pressure,
2102 .stream_memory_free = tcp_stream_memory_free,
2103 .sockets_allocated = &tcp_sockets_allocated,
2104 .memory_allocated = &tcp_memory_allocated,
2105 .memory_pressure = &tcp_memory_pressure,
2106 .orphan_count = &tcp_orphan_count,
2107 .sysctl_mem = sysctl_tcp_mem,
2108 .sysctl_wmem_offset = offsetof(struct net, ipv4.sysctl_tcp_wmem),
2109 .sysctl_rmem_offset = offsetof(struct net, ipv4.sysctl_tcp_rmem),
2110 .max_header = MAX_TCP_HEADER,
2111 .obj_size = sizeof(struct tcp6_sock),
2112 .slab_flags = SLAB_TYPESAFE_BY_RCU,
2113 .twsk_prot = &tcp6_timewait_sock_ops,
2114 .rsk_prot = &tcp6_request_sock_ops,
2115 .h.hashinfo = &tcp_hashinfo,
2116 .no_autobind = true,
2117 .diag_destroy = tcp_abort,
2118};
2119EXPORT_SYMBOL_GPL(tcpv6_prot);
2120
2121/* thinking of making this const? Don't.
2122 * early_demux can change based on sysctl.
2123 */
2124static struct inet6_protocol tcpv6_protocol = {
2125 .early_demux = tcp_v6_early_demux,
2126 .early_demux_handler = tcp_v6_early_demux,
2127 .handler = tcp_v6_rcv,
2128 .err_handler = tcp_v6_err,
2129 .flags = INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
2130};
2131
2132static struct inet_protosw tcpv6_protosw = {
2133 .type = SOCK_STREAM,
2134 .protocol = IPPROTO_TCP,
2135 .prot = &tcpv6_prot,
2136 .ops = &inet6_stream_ops,
2137 .flags = INET_PROTOSW_PERMANENT |
2138 INET_PROTOSW_ICSK,
2139};
2140
2141static int __net_init tcpv6_net_init(struct net *net)
2142{
2143 return inet_ctl_sock_create(&net->ipv6.tcp_sk, PF_INET6,
2144 SOCK_RAW, IPPROTO_TCP, net);
2145}
2146
2147static void __net_exit tcpv6_net_exit(struct net *net)
2148{
2149 inet_ctl_sock_destroy(net->ipv6.tcp_sk);
2150}
2151
2152static void __net_exit tcpv6_net_exit_batch(struct list_head *net_exit_list)
2153{
2154 inet_twsk_purge(&tcp_hashinfo, AF_INET6);
2155}
2156
2157static struct pernet_operations tcpv6_net_ops = {
2158 .init = tcpv6_net_init,
2159 .exit = tcpv6_net_exit,
2160 .exit_batch = tcpv6_net_exit_batch,
2161};
2162
2163int __init tcpv6_init(void)
2164{
2165 int ret;
2166
2167 ret = inet6_add_protocol(&tcpv6_protocol, IPPROTO_TCP);
2168 if (ret)
2169 goto out;
2170
2171 /* register inet6 protocol */
2172 ret = inet6_register_protosw(&tcpv6_protosw);
2173 if (ret)
2174 goto out_tcpv6_protocol;
2175
2176 ret = register_pernet_subsys(&tcpv6_net_ops);
2177 if (ret)
2178 goto out_tcpv6_protosw;
2179
2180 ret = mptcpv6_init();
2181 if (ret)
2182 goto out_tcpv6_pernet_subsys;
2183
2184out:
2185 return ret;
2186
2187out_tcpv6_pernet_subsys:
2188 unregister_pernet_subsys(&tcpv6_net_ops);
2189out_tcpv6_protosw:
2190 inet6_unregister_protosw(&tcpv6_protosw);
2191out_tcpv6_protocol:
2192 inet6_del_protocol(&tcpv6_protocol, IPPROTO_TCP);
2193 goto out;
2194}
2195
2196void tcpv6_exit(void)
2197{
2198 unregister_pernet_subsys(&tcpv6_net_ops);
2199 inet6_unregister_protosw(&tcpv6_protosw);
2200 inet6_del_protocol(&tcpv6_protocol, IPPROTO_TCP);
2201}
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * TCP over IPv6
4 * Linux INET6 implementation
5 *
6 * Authors:
7 * Pedro Roque <roque@di.fc.ul.pt>
8 *
9 * Based on:
10 * linux/net/ipv4/tcp.c
11 * linux/net/ipv4/tcp_input.c
12 * linux/net/ipv4/tcp_output.c
13 *
14 * Fixes:
15 * Hideaki YOSHIFUJI : sin6_scope_id support
16 * YOSHIFUJI Hideaki @USAGI and: Support IPV6_V6ONLY socket option, which
17 * Alexey Kuznetsov allow both IPv4 and IPv6 sockets to bind
18 * a single port at the same time.
19 * YOSHIFUJI Hideaki @USAGI: convert /proc/net/tcp6 to seq_file.
20 */
21
22#include <linux/bottom_half.h>
23#include <linux/module.h>
24#include <linux/errno.h>
25#include <linux/types.h>
26#include <linux/socket.h>
27#include <linux/sockios.h>
28#include <linux/net.h>
29#include <linux/jiffies.h>
30#include <linux/in.h>
31#include <linux/in6.h>
32#include <linux/netdevice.h>
33#include <linux/init.h>
34#include <linux/jhash.h>
35#include <linux/ipsec.h>
36#include <linux/times.h>
37#include <linux/slab.h>
38#include <linux/uaccess.h>
39#include <linux/ipv6.h>
40#include <linux/icmpv6.h>
41#include <linux/random.h>
42#include <linux/indirect_call_wrapper.h>
43
44#include <net/tcp.h>
45#include <net/ndisc.h>
46#include <net/inet6_hashtables.h>
47#include <net/inet6_connection_sock.h>
48#include <net/ipv6.h>
49#include <net/transp_v6.h>
50#include <net/addrconf.h>
51#include <net/ip6_route.h>
52#include <net/ip6_checksum.h>
53#include <net/inet_ecn.h>
54#include <net/protocol.h>
55#include <net/xfrm.h>
56#include <net/snmp.h>
57#include <net/dsfield.h>
58#include <net/timewait_sock.h>
59#include <net/inet_common.h>
60#include <net/secure_seq.h>
61#include <net/hotdata.h>
62#include <net/busy_poll.h>
63
64#include <linux/proc_fs.h>
65#include <linux/seq_file.h>
66
67#include <crypto/hash.h>
68#include <linux/scatterlist.h>
69
70#include <trace/events/tcp.h>
71
72static void tcp_v6_send_reset(const struct sock *sk, struct sk_buff *skb);
73static void tcp_v6_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb,
74 struct request_sock *req);
75
76INDIRECT_CALLABLE_SCOPE int tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb);
77
78static const struct inet_connection_sock_af_ops ipv6_mapped;
79const struct inet_connection_sock_af_ops ipv6_specific;
80#if defined(CONFIG_TCP_MD5SIG) || defined(CONFIG_TCP_AO)
81static const struct tcp_sock_af_ops tcp_sock_ipv6_specific;
82static const struct tcp_sock_af_ops tcp_sock_ipv6_mapped_specific;
83#endif
84
85/* Helper returning the inet6 address from a given tcp socket.
86 * It can be used in TCP stack instead of inet6_sk(sk).
87 * This avoids a dereference and allow compiler optimizations.
88 * It is a specialized version of inet6_sk_generic().
89 */
90#define tcp_inet6_sk(sk) (&container_of_const(tcp_sk(sk), \
91 struct tcp6_sock, tcp)->inet6)
92
93static void inet6_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb)
94{
95 struct dst_entry *dst = skb_dst(skb);
96
97 if (dst && dst_hold_safe(dst)) {
98 rcu_assign_pointer(sk->sk_rx_dst, dst);
99 sk->sk_rx_dst_ifindex = skb->skb_iif;
100 sk->sk_rx_dst_cookie = rt6_get_cookie(dst_rt6_info(dst));
101 }
102}
103
104static u32 tcp_v6_init_seq(const struct sk_buff *skb)
105{
106 return secure_tcpv6_seq(ipv6_hdr(skb)->daddr.s6_addr32,
107 ipv6_hdr(skb)->saddr.s6_addr32,
108 tcp_hdr(skb)->dest,
109 tcp_hdr(skb)->source);
110}
111
112static u32 tcp_v6_init_ts_off(const struct net *net, const struct sk_buff *skb)
113{
114 return secure_tcpv6_ts_off(net, ipv6_hdr(skb)->daddr.s6_addr32,
115 ipv6_hdr(skb)->saddr.s6_addr32);
116}
117
118static int tcp_v6_pre_connect(struct sock *sk, struct sockaddr *uaddr,
119 int addr_len)
120{
121 /* This check is replicated from tcp_v6_connect() and intended to
122 * prevent BPF program called below from accessing bytes that are out
123 * of the bound specified by user in addr_len.
124 */
125 if (addr_len < SIN6_LEN_RFC2133)
126 return -EINVAL;
127
128 sock_owned_by_me(sk);
129
130 return BPF_CGROUP_RUN_PROG_INET6_CONNECT(sk, uaddr, &addr_len);
131}
132
133static int tcp_v6_connect(struct sock *sk, struct sockaddr *uaddr,
134 int addr_len)
135{
136 struct sockaddr_in6 *usin = (struct sockaddr_in6 *) uaddr;
137 struct inet_connection_sock *icsk = inet_csk(sk);
138 struct in6_addr *saddr = NULL, *final_p, final;
139 struct inet_timewait_death_row *tcp_death_row;
140 struct ipv6_pinfo *np = tcp_inet6_sk(sk);
141 struct inet_sock *inet = inet_sk(sk);
142 struct tcp_sock *tp = tcp_sk(sk);
143 struct net *net = sock_net(sk);
144 struct ipv6_txoptions *opt;
145 struct dst_entry *dst;
146 struct flowi6 fl6;
147 int addr_type;
148 int err;
149
150 if (addr_len < SIN6_LEN_RFC2133)
151 return -EINVAL;
152
153 if (usin->sin6_family != AF_INET6)
154 return -EAFNOSUPPORT;
155
156 memset(&fl6, 0, sizeof(fl6));
157
158 if (inet6_test_bit(SNDFLOW, sk)) {
159 fl6.flowlabel = usin->sin6_flowinfo&IPV6_FLOWINFO_MASK;
160 IP6_ECN_flow_init(fl6.flowlabel);
161 if (fl6.flowlabel&IPV6_FLOWLABEL_MASK) {
162 struct ip6_flowlabel *flowlabel;
163 flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
164 if (IS_ERR(flowlabel))
165 return -EINVAL;
166 fl6_sock_release(flowlabel);
167 }
168 }
169
170 /*
171 * connect() to INADDR_ANY means loopback (BSD'ism).
172 */
173
174 if (ipv6_addr_any(&usin->sin6_addr)) {
175 if (ipv6_addr_v4mapped(&sk->sk_v6_rcv_saddr))
176 ipv6_addr_set_v4mapped(htonl(INADDR_LOOPBACK),
177 &usin->sin6_addr);
178 else
179 usin->sin6_addr = in6addr_loopback;
180 }
181
182 addr_type = ipv6_addr_type(&usin->sin6_addr);
183
184 if (addr_type & IPV6_ADDR_MULTICAST)
185 return -ENETUNREACH;
186
187 if (addr_type&IPV6_ADDR_LINKLOCAL) {
188 if (addr_len >= sizeof(struct sockaddr_in6) &&
189 usin->sin6_scope_id) {
190 /* If interface is set while binding, indices
191 * must coincide.
192 */
193 if (!sk_dev_equal_l3scope(sk, usin->sin6_scope_id))
194 return -EINVAL;
195
196 sk->sk_bound_dev_if = usin->sin6_scope_id;
197 }
198
199 /* Connect to link-local address requires an interface */
200 if (!sk->sk_bound_dev_if)
201 return -EINVAL;
202 }
203
204 if (tp->rx_opt.ts_recent_stamp &&
205 !ipv6_addr_equal(&sk->sk_v6_daddr, &usin->sin6_addr)) {
206 tp->rx_opt.ts_recent = 0;
207 tp->rx_opt.ts_recent_stamp = 0;
208 WRITE_ONCE(tp->write_seq, 0);
209 }
210
211 sk->sk_v6_daddr = usin->sin6_addr;
212 np->flow_label = fl6.flowlabel;
213
214 /*
215 * TCP over IPv4
216 */
217
218 if (addr_type & IPV6_ADDR_MAPPED) {
219 u32 exthdrlen = icsk->icsk_ext_hdr_len;
220 struct sockaddr_in sin;
221
222 if (ipv6_only_sock(sk))
223 return -ENETUNREACH;
224
225 sin.sin_family = AF_INET;
226 sin.sin_port = usin->sin6_port;
227 sin.sin_addr.s_addr = usin->sin6_addr.s6_addr32[3];
228
229 /* Paired with READ_ONCE() in tcp_(get|set)sockopt() */
230 WRITE_ONCE(icsk->icsk_af_ops, &ipv6_mapped);
231 if (sk_is_mptcp(sk))
232 mptcpv6_handle_mapped(sk, true);
233 sk->sk_backlog_rcv = tcp_v4_do_rcv;
234#if defined(CONFIG_TCP_MD5SIG) || defined(CONFIG_TCP_AO)
235 tp->af_specific = &tcp_sock_ipv6_mapped_specific;
236#endif
237
238 err = tcp_v4_connect(sk, (struct sockaddr *)&sin, sizeof(sin));
239
240 if (err) {
241 icsk->icsk_ext_hdr_len = exthdrlen;
242 /* Paired with READ_ONCE() in tcp_(get|set)sockopt() */
243 WRITE_ONCE(icsk->icsk_af_ops, &ipv6_specific);
244 if (sk_is_mptcp(sk))
245 mptcpv6_handle_mapped(sk, false);
246 sk->sk_backlog_rcv = tcp_v6_do_rcv;
247#if defined(CONFIG_TCP_MD5SIG) || defined(CONFIG_TCP_AO)
248 tp->af_specific = &tcp_sock_ipv6_specific;
249#endif
250 goto failure;
251 }
252 np->saddr = sk->sk_v6_rcv_saddr;
253
254 return err;
255 }
256
257 if (!ipv6_addr_any(&sk->sk_v6_rcv_saddr))
258 saddr = &sk->sk_v6_rcv_saddr;
259
260 fl6.flowi6_proto = IPPROTO_TCP;
261 fl6.daddr = sk->sk_v6_daddr;
262 fl6.saddr = saddr ? *saddr : np->saddr;
263 fl6.flowlabel = ip6_make_flowinfo(np->tclass, np->flow_label);
264 fl6.flowi6_oif = sk->sk_bound_dev_if;
265 fl6.flowi6_mark = sk->sk_mark;
266 fl6.fl6_dport = usin->sin6_port;
267 fl6.fl6_sport = inet->inet_sport;
268 fl6.flowi6_uid = sk->sk_uid;
269
270 opt = rcu_dereference_protected(np->opt, lockdep_sock_is_held(sk));
271 final_p = fl6_update_dst(&fl6, opt, &final);
272
273 security_sk_classify_flow(sk, flowi6_to_flowi_common(&fl6));
274
275 dst = ip6_dst_lookup_flow(net, sk, &fl6, final_p);
276 if (IS_ERR(dst)) {
277 err = PTR_ERR(dst);
278 goto failure;
279 }
280
281 tp->tcp_usec_ts = dst_tcp_usec_ts(dst);
282 tcp_death_row = &sock_net(sk)->ipv4.tcp_death_row;
283
284 if (!saddr) {
285 saddr = &fl6.saddr;
286
287 err = inet_bhash2_update_saddr(sk, saddr, AF_INET6);
288 if (err)
289 goto failure;
290 }
291
292 /* set the source address */
293 np->saddr = *saddr;
294 inet->inet_rcv_saddr = LOOPBACK4_IPV6;
295
296 sk->sk_gso_type = SKB_GSO_TCPV6;
297 ip6_dst_store(sk, dst, NULL, NULL);
298
299 icsk->icsk_ext_hdr_len = 0;
300 if (opt)
301 icsk->icsk_ext_hdr_len = opt->opt_flen +
302 opt->opt_nflen;
303
304 tp->rx_opt.mss_clamp = IPV6_MIN_MTU - sizeof(struct tcphdr) - sizeof(struct ipv6hdr);
305
306 inet->inet_dport = usin->sin6_port;
307
308 tcp_set_state(sk, TCP_SYN_SENT);
309 err = inet6_hash_connect(tcp_death_row, sk);
310 if (err)
311 goto late_failure;
312
313 sk_set_txhash(sk);
314
315 if (likely(!tp->repair)) {
316 if (!tp->write_seq)
317 WRITE_ONCE(tp->write_seq,
318 secure_tcpv6_seq(np->saddr.s6_addr32,
319 sk->sk_v6_daddr.s6_addr32,
320 inet->inet_sport,
321 inet->inet_dport));
322 tp->tsoffset = secure_tcpv6_ts_off(net, np->saddr.s6_addr32,
323 sk->sk_v6_daddr.s6_addr32);
324 }
325
326 if (tcp_fastopen_defer_connect(sk, &err))
327 return err;
328 if (err)
329 goto late_failure;
330
331 err = tcp_connect(sk);
332 if (err)
333 goto late_failure;
334
335 return 0;
336
337late_failure:
338 tcp_set_state(sk, TCP_CLOSE);
339 inet_bhash2_reset_saddr(sk);
340failure:
341 inet->inet_dport = 0;
342 sk->sk_route_caps = 0;
343 return err;
344}
345
346static void tcp_v6_mtu_reduced(struct sock *sk)
347{
348 struct dst_entry *dst;
349 u32 mtu;
350
351 if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE))
352 return;
353
354 mtu = READ_ONCE(tcp_sk(sk)->mtu_info);
355
356 /* Drop requests trying to increase our current mss.
357 * Check done in __ip6_rt_update_pmtu() is too late.
358 */
359 if (tcp_mtu_to_mss(sk, mtu) >= tcp_sk(sk)->mss_cache)
360 return;
361
362 dst = inet6_csk_update_pmtu(sk, mtu);
363 if (!dst)
364 return;
365
366 if (inet_csk(sk)->icsk_pmtu_cookie > dst_mtu(dst)) {
367 tcp_sync_mss(sk, dst_mtu(dst));
368 tcp_simple_retransmit(sk);
369 }
370}
371
372static int tcp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
373 u8 type, u8 code, int offset, __be32 info)
374{
375 const struct ipv6hdr *hdr = (const struct ipv6hdr *)skb->data;
376 const struct tcphdr *th = (struct tcphdr *)(skb->data+offset);
377 struct net *net = dev_net(skb->dev);
378 struct request_sock *fastopen;
379 struct ipv6_pinfo *np;
380 struct tcp_sock *tp;
381 __u32 seq, snd_una;
382 struct sock *sk;
383 bool fatal;
384 int err;
385
386 sk = __inet6_lookup_established(net, net->ipv4.tcp_death_row.hashinfo,
387 &hdr->daddr, th->dest,
388 &hdr->saddr, ntohs(th->source),
389 skb->dev->ifindex, inet6_sdif(skb));
390
391 if (!sk) {
392 __ICMP6_INC_STATS(net, __in6_dev_get(skb->dev),
393 ICMP6_MIB_INERRORS);
394 return -ENOENT;
395 }
396
397 if (sk->sk_state == TCP_TIME_WAIT) {
398 /* To increase the counter of ignored icmps for TCP-AO */
399 tcp_ao_ignore_icmp(sk, AF_INET6, type, code);
400 inet_twsk_put(inet_twsk(sk));
401 return 0;
402 }
403 seq = ntohl(th->seq);
404 fatal = icmpv6_err_convert(type, code, &err);
405 if (sk->sk_state == TCP_NEW_SYN_RECV) {
406 tcp_req_err(sk, seq, fatal);
407 return 0;
408 }
409
410 if (tcp_ao_ignore_icmp(sk, AF_INET6, type, code)) {
411 sock_put(sk);
412 return 0;
413 }
414
415 bh_lock_sock(sk);
416 if (sock_owned_by_user(sk) && type != ICMPV6_PKT_TOOBIG)
417 __NET_INC_STATS(net, LINUX_MIB_LOCKDROPPEDICMPS);
418
419 if (sk->sk_state == TCP_CLOSE)
420 goto out;
421
422 if (static_branch_unlikely(&ip6_min_hopcount)) {
423 /* min_hopcount can be changed concurrently from do_ipv6_setsockopt() */
424 if (ipv6_hdr(skb)->hop_limit < READ_ONCE(tcp_inet6_sk(sk)->min_hopcount)) {
425 __NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP);
426 goto out;
427 }
428 }
429
430 tp = tcp_sk(sk);
431 /* XXX (TFO) - tp->snd_una should be ISN (tcp_create_openreq_child() */
432 fastopen = rcu_dereference(tp->fastopen_rsk);
433 snd_una = fastopen ? tcp_rsk(fastopen)->snt_isn : tp->snd_una;
434 if (sk->sk_state != TCP_LISTEN &&
435 !between(seq, snd_una, tp->snd_nxt)) {
436 __NET_INC_STATS(net, LINUX_MIB_OUTOFWINDOWICMPS);
437 goto out;
438 }
439
440 np = tcp_inet6_sk(sk);
441
442 if (type == NDISC_REDIRECT) {
443 if (!sock_owned_by_user(sk)) {
444 struct dst_entry *dst = __sk_dst_check(sk, np->dst_cookie);
445
446 if (dst)
447 dst->ops->redirect(dst, sk, skb);
448 }
449 goto out;
450 }
451
452 if (type == ICMPV6_PKT_TOOBIG) {
453 u32 mtu = ntohl(info);
454
455 /* We are not interested in TCP_LISTEN and open_requests
456 * (SYN-ACKs send out by Linux are always <576bytes so
457 * they should go through unfragmented).
458 */
459 if (sk->sk_state == TCP_LISTEN)
460 goto out;
461
462 if (!ip6_sk_accept_pmtu(sk))
463 goto out;
464
465 if (mtu < IPV6_MIN_MTU)
466 goto out;
467
468 WRITE_ONCE(tp->mtu_info, mtu);
469
470 if (!sock_owned_by_user(sk))
471 tcp_v6_mtu_reduced(sk);
472 else if (!test_and_set_bit(TCP_MTU_REDUCED_DEFERRED,
473 &sk->sk_tsq_flags))
474 sock_hold(sk);
475 goto out;
476 }
477
478
479 /* Might be for an request_sock */
480 switch (sk->sk_state) {
481 case TCP_SYN_SENT:
482 case TCP_SYN_RECV:
483 /* Only in fast or simultaneous open. If a fast open socket is
484 * already accepted it is treated as a connected one below.
485 */
486 if (fastopen && !fastopen->sk)
487 break;
488
489 ipv6_icmp_error(sk, skb, err, th->dest, ntohl(info), (u8 *)th);
490
491 if (!sock_owned_by_user(sk)) {
492 WRITE_ONCE(sk->sk_err, err);
493 sk_error_report(sk); /* Wake people up to see the error (see connect in sock.c) */
494
495 tcp_done(sk);
496 } else {
497 WRITE_ONCE(sk->sk_err_soft, err);
498 }
499 goto out;
500 case TCP_LISTEN:
501 break;
502 default:
503 /* check if this ICMP message allows revert of backoff.
504 * (see RFC 6069)
505 */
506 if (!fastopen && type == ICMPV6_DEST_UNREACH &&
507 code == ICMPV6_NOROUTE)
508 tcp_ld_RTO_revert(sk, seq);
509 }
510
511 if (!sock_owned_by_user(sk) && inet6_test_bit(RECVERR6, sk)) {
512 WRITE_ONCE(sk->sk_err, err);
513 sk_error_report(sk);
514 } else {
515 WRITE_ONCE(sk->sk_err_soft, err);
516 }
517out:
518 bh_unlock_sock(sk);
519 sock_put(sk);
520 return 0;
521}
522
523
524static int tcp_v6_send_synack(const struct sock *sk, struct dst_entry *dst,
525 struct flowi *fl,
526 struct request_sock *req,
527 struct tcp_fastopen_cookie *foc,
528 enum tcp_synack_type synack_type,
529 struct sk_buff *syn_skb)
530{
531 struct inet_request_sock *ireq = inet_rsk(req);
532 const struct ipv6_pinfo *np = tcp_inet6_sk(sk);
533 struct ipv6_txoptions *opt;
534 struct flowi6 *fl6 = &fl->u.ip6;
535 struct sk_buff *skb;
536 int err = -ENOMEM;
537 u8 tclass;
538
539 /* First, grab a route. */
540 if (!dst && (dst = inet6_csk_route_req(sk, fl6, req,
541 IPPROTO_TCP)) == NULL)
542 goto done;
543
544 skb = tcp_make_synack(sk, dst, req, foc, synack_type, syn_skb);
545
546 if (skb) {
547 __tcp_v6_send_check(skb, &ireq->ir_v6_loc_addr,
548 &ireq->ir_v6_rmt_addr);
549
550 fl6->daddr = ireq->ir_v6_rmt_addr;
551 if (inet6_test_bit(REPFLOW, sk) && ireq->pktopts)
552 fl6->flowlabel = ip6_flowlabel(ipv6_hdr(ireq->pktopts));
553
554 tclass = READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_reflect_tos) ?
555 (tcp_rsk(req)->syn_tos & ~INET_ECN_MASK) |
556 (np->tclass & INET_ECN_MASK) :
557 np->tclass;
558
559 if (!INET_ECN_is_capable(tclass) &&
560 tcp_bpf_ca_needs_ecn((struct sock *)req))
561 tclass |= INET_ECN_ECT_0;
562
563 rcu_read_lock();
564 opt = ireq->ipv6_opt;
565 if (!opt)
566 opt = rcu_dereference(np->opt);
567 err = ip6_xmit(sk, skb, fl6, skb->mark ? : READ_ONCE(sk->sk_mark),
568 opt, tclass, READ_ONCE(sk->sk_priority));
569 rcu_read_unlock();
570 err = net_xmit_eval(err);
571 }
572
573done:
574 return err;
575}
576
577
578static void tcp_v6_reqsk_destructor(struct request_sock *req)
579{
580 kfree(inet_rsk(req)->ipv6_opt);
581 consume_skb(inet_rsk(req)->pktopts);
582}
583
584#ifdef CONFIG_TCP_MD5SIG
585static struct tcp_md5sig_key *tcp_v6_md5_do_lookup(const struct sock *sk,
586 const struct in6_addr *addr,
587 int l3index)
588{
589 return tcp_md5_do_lookup(sk, l3index,
590 (union tcp_md5_addr *)addr, AF_INET6);
591}
592
593static struct tcp_md5sig_key *tcp_v6_md5_lookup(const struct sock *sk,
594 const struct sock *addr_sk)
595{
596 int l3index;
597
598 l3index = l3mdev_master_ifindex_by_index(sock_net(sk),
599 addr_sk->sk_bound_dev_if);
600 return tcp_v6_md5_do_lookup(sk, &addr_sk->sk_v6_daddr,
601 l3index);
602}
603
604static int tcp_v6_parse_md5_keys(struct sock *sk, int optname,
605 sockptr_t optval, int optlen)
606{
607 struct tcp_md5sig cmd;
608 struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)&cmd.tcpm_addr;
609 union tcp_ao_addr *addr;
610 int l3index = 0;
611 u8 prefixlen;
612 bool l3flag;
613 u8 flags;
614
615 if (optlen < sizeof(cmd))
616 return -EINVAL;
617
618 if (copy_from_sockptr(&cmd, optval, sizeof(cmd)))
619 return -EFAULT;
620
621 if (sin6->sin6_family != AF_INET6)
622 return -EINVAL;
623
624 flags = cmd.tcpm_flags & TCP_MD5SIG_FLAG_IFINDEX;
625 l3flag = cmd.tcpm_flags & TCP_MD5SIG_FLAG_IFINDEX;
626
627 if (optname == TCP_MD5SIG_EXT &&
628 cmd.tcpm_flags & TCP_MD5SIG_FLAG_PREFIX) {
629 prefixlen = cmd.tcpm_prefixlen;
630 if (prefixlen > 128 || (ipv6_addr_v4mapped(&sin6->sin6_addr) &&
631 prefixlen > 32))
632 return -EINVAL;
633 } else {
634 prefixlen = ipv6_addr_v4mapped(&sin6->sin6_addr) ? 32 : 128;
635 }
636
637 if (optname == TCP_MD5SIG_EXT && cmd.tcpm_ifindex &&
638 cmd.tcpm_flags & TCP_MD5SIG_FLAG_IFINDEX) {
639 struct net_device *dev;
640
641 rcu_read_lock();
642 dev = dev_get_by_index_rcu(sock_net(sk), cmd.tcpm_ifindex);
643 if (dev && netif_is_l3_master(dev))
644 l3index = dev->ifindex;
645 rcu_read_unlock();
646
647 /* ok to reference set/not set outside of rcu;
648 * right now device MUST be an L3 master
649 */
650 if (!dev || !l3index)
651 return -EINVAL;
652 }
653
654 if (!cmd.tcpm_keylen) {
655 if (ipv6_addr_v4mapped(&sin6->sin6_addr))
656 return tcp_md5_do_del(sk, (union tcp_md5_addr *)&sin6->sin6_addr.s6_addr32[3],
657 AF_INET, prefixlen,
658 l3index, flags);
659 return tcp_md5_do_del(sk, (union tcp_md5_addr *)&sin6->sin6_addr,
660 AF_INET6, prefixlen, l3index, flags);
661 }
662
663 if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN)
664 return -EINVAL;
665
666 if (ipv6_addr_v4mapped(&sin6->sin6_addr)) {
667 addr = (union tcp_md5_addr *)&sin6->sin6_addr.s6_addr32[3];
668
669 /* Don't allow keys for peers that have a matching TCP-AO key.
670 * See the comment in tcp_ao_add_cmd()
671 */
672 if (tcp_ao_required(sk, addr, AF_INET,
673 l3flag ? l3index : -1, false))
674 return -EKEYREJECTED;
675 return tcp_md5_do_add(sk, addr,
676 AF_INET, prefixlen, l3index, flags,
677 cmd.tcpm_key, cmd.tcpm_keylen);
678 }
679
680 addr = (union tcp_md5_addr *)&sin6->sin6_addr;
681
682 /* Don't allow keys for peers that have a matching TCP-AO key.
683 * See the comment in tcp_ao_add_cmd()
684 */
685 if (tcp_ao_required(sk, addr, AF_INET6, l3flag ? l3index : -1, false))
686 return -EKEYREJECTED;
687
688 return tcp_md5_do_add(sk, addr, AF_INET6, prefixlen, l3index, flags,
689 cmd.tcpm_key, cmd.tcpm_keylen);
690}
691
692static int tcp_v6_md5_hash_headers(struct tcp_sigpool *hp,
693 const struct in6_addr *daddr,
694 const struct in6_addr *saddr,
695 const struct tcphdr *th, int nbytes)
696{
697 struct tcp6_pseudohdr *bp;
698 struct scatterlist sg;
699 struct tcphdr *_th;
700
701 bp = hp->scratch;
702 /* 1. TCP pseudo-header (RFC2460) */
703 bp->saddr = *saddr;
704 bp->daddr = *daddr;
705 bp->protocol = cpu_to_be32(IPPROTO_TCP);
706 bp->len = cpu_to_be32(nbytes);
707
708 _th = (struct tcphdr *)(bp + 1);
709 memcpy(_th, th, sizeof(*th));
710 _th->check = 0;
711
712 sg_init_one(&sg, bp, sizeof(*bp) + sizeof(*th));
713 ahash_request_set_crypt(hp->req, &sg, NULL,
714 sizeof(*bp) + sizeof(*th));
715 return crypto_ahash_update(hp->req);
716}
717
718static int tcp_v6_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key,
719 const struct in6_addr *daddr, struct in6_addr *saddr,
720 const struct tcphdr *th)
721{
722 struct tcp_sigpool hp;
723
724 if (tcp_sigpool_start(tcp_md5_sigpool_id, &hp))
725 goto clear_hash_nostart;
726
727 if (crypto_ahash_init(hp.req))
728 goto clear_hash;
729 if (tcp_v6_md5_hash_headers(&hp, daddr, saddr, th, th->doff << 2))
730 goto clear_hash;
731 if (tcp_md5_hash_key(&hp, key))
732 goto clear_hash;
733 ahash_request_set_crypt(hp.req, NULL, md5_hash, 0);
734 if (crypto_ahash_final(hp.req))
735 goto clear_hash;
736
737 tcp_sigpool_end(&hp);
738 return 0;
739
740clear_hash:
741 tcp_sigpool_end(&hp);
742clear_hash_nostart:
743 memset(md5_hash, 0, 16);
744 return 1;
745}
746
747static int tcp_v6_md5_hash_skb(char *md5_hash,
748 const struct tcp_md5sig_key *key,
749 const struct sock *sk,
750 const struct sk_buff *skb)
751{
752 const struct tcphdr *th = tcp_hdr(skb);
753 const struct in6_addr *saddr, *daddr;
754 struct tcp_sigpool hp;
755
756 if (sk) { /* valid for establish/request sockets */
757 saddr = &sk->sk_v6_rcv_saddr;
758 daddr = &sk->sk_v6_daddr;
759 } else {
760 const struct ipv6hdr *ip6h = ipv6_hdr(skb);
761 saddr = &ip6h->saddr;
762 daddr = &ip6h->daddr;
763 }
764
765 if (tcp_sigpool_start(tcp_md5_sigpool_id, &hp))
766 goto clear_hash_nostart;
767
768 if (crypto_ahash_init(hp.req))
769 goto clear_hash;
770
771 if (tcp_v6_md5_hash_headers(&hp, daddr, saddr, th, skb->len))
772 goto clear_hash;
773 if (tcp_sigpool_hash_skb_data(&hp, skb, th->doff << 2))
774 goto clear_hash;
775 if (tcp_md5_hash_key(&hp, key))
776 goto clear_hash;
777 ahash_request_set_crypt(hp.req, NULL, md5_hash, 0);
778 if (crypto_ahash_final(hp.req))
779 goto clear_hash;
780
781 tcp_sigpool_end(&hp);
782 return 0;
783
784clear_hash:
785 tcp_sigpool_end(&hp);
786clear_hash_nostart:
787 memset(md5_hash, 0, 16);
788 return 1;
789}
790#endif
791
792static void tcp_v6_init_req(struct request_sock *req,
793 const struct sock *sk_listener,
794 struct sk_buff *skb)
795{
796 bool l3_slave = ipv6_l3mdev_skb(TCP_SKB_CB(skb)->header.h6.flags);
797 struct inet_request_sock *ireq = inet_rsk(req);
798 const struct ipv6_pinfo *np = tcp_inet6_sk(sk_listener);
799
800 ireq->ir_v6_rmt_addr = ipv6_hdr(skb)->saddr;
801 ireq->ir_v6_loc_addr = ipv6_hdr(skb)->daddr;
802
803 /* So that link locals have meaning */
804 if ((!sk_listener->sk_bound_dev_if || l3_slave) &&
805 ipv6_addr_type(&ireq->ir_v6_rmt_addr) & IPV6_ADDR_LINKLOCAL)
806 ireq->ir_iif = tcp_v6_iif(skb);
807
808 if (!TCP_SKB_CB(skb)->tcp_tw_isn &&
809 (ipv6_opt_accepted(sk_listener, skb, &TCP_SKB_CB(skb)->header.h6) ||
810 np->rxopt.bits.rxinfo ||
811 np->rxopt.bits.rxoinfo || np->rxopt.bits.rxhlim ||
812 np->rxopt.bits.rxohlim || inet6_test_bit(REPFLOW, sk_listener))) {
813 refcount_inc(&skb->users);
814 ireq->pktopts = skb;
815 }
816}
817
818static struct dst_entry *tcp_v6_route_req(const struct sock *sk,
819 struct sk_buff *skb,
820 struct flowi *fl,
821 struct request_sock *req)
822{
823 tcp_v6_init_req(req, sk, skb);
824
825 if (security_inet_conn_request(sk, skb, req))
826 return NULL;
827
828 return inet6_csk_route_req(sk, &fl->u.ip6, req, IPPROTO_TCP);
829}
830
831struct request_sock_ops tcp6_request_sock_ops __read_mostly = {
832 .family = AF_INET6,
833 .obj_size = sizeof(struct tcp6_request_sock),
834 .rtx_syn_ack = tcp_rtx_synack,
835 .send_ack = tcp_v6_reqsk_send_ack,
836 .destructor = tcp_v6_reqsk_destructor,
837 .send_reset = tcp_v6_send_reset,
838 .syn_ack_timeout = tcp_syn_ack_timeout,
839};
840
841const struct tcp_request_sock_ops tcp_request_sock_ipv6_ops = {
842 .mss_clamp = IPV6_MIN_MTU - sizeof(struct tcphdr) -
843 sizeof(struct ipv6hdr),
844#ifdef CONFIG_TCP_MD5SIG
845 .req_md5_lookup = tcp_v6_md5_lookup,
846 .calc_md5_hash = tcp_v6_md5_hash_skb,
847#endif
848#ifdef CONFIG_TCP_AO
849 .ao_lookup = tcp_v6_ao_lookup_rsk,
850 .ao_calc_key = tcp_v6_ao_calc_key_rsk,
851 .ao_synack_hash = tcp_v6_ao_synack_hash,
852#endif
853#ifdef CONFIG_SYN_COOKIES
854 .cookie_init_seq = cookie_v6_init_sequence,
855#endif
856 .route_req = tcp_v6_route_req,
857 .init_seq = tcp_v6_init_seq,
858 .init_ts_off = tcp_v6_init_ts_off,
859 .send_synack = tcp_v6_send_synack,
860};
861
862static void tcp_v6_send_response(const struct sock *sk, struct sk_buff *skb, u32 seq,
863 u32 ack, u32 win, u32 tsval, u32 tsecr,
864 int oif, int rst, u8 tclass, __be32 label,
865 u32 priority, u32 txhash, struct tcp_key *key)
866{
867 const struct tcphdr *th = tcp_hdr(skb);
868 struct tcphdr *t1;
869 struct sk_buff *buff;
870 struct flowi6 fl6;
871 struct net *net = sk ? sock_net(sk) : dev_net(skb_dst(skb)->dev);
872 struct sock *ctl_sk = net->ipv6.tcp_sk;
873 unsigned int tot_len = sizeof(struct tcphdr);
874 __be32 mrst = 0, *topt;
875 struct dst_entry *dst;
876 __u32 mark = 0;
877
878 if (tsecr)
879 tot_len += TCPOLEN_TSTAMP_ALIGNED;
880 if (tcp_key_is_md5(key))
881 tot_len += TCPOLEN_MD5SIG_ALIGNED;
882 if (tcp_key_is_ao(key))
883 tot_len += tcp_ao_len_aligned(key->ao_key);
884
885#ifdef CONFIG_MPTCP
886 if (rst && !tcp_key_is_md5(key)) {
887 mrst = mptcp_reset_option(skb);
888
889 if (mrst)
890 tot_len += sizeof(__be32);
891 }
892#endif
893
894 buff = alloc_skb(MAX_TCP_HEADER, GFP_ATOMIC);
895 if (!buff)
896 return;
897
898 skb_reserve(buff, MAX_TCP_HEADER);
899
900 t1 = skb_push(buff, tot_len);
901 skb_reset_transport_header(buff);
902
903 /* Swap the send and the receive. */
904 memset(t1, 0, sizeof(*t1));
905 t1->dest = th->source;
906 t1->source = th->dest;
907 t1->doff = tot_len / 4;
908 t1->seq = htonl(seq);
909 t1->ack_seq = htonl(ack);
910 t1->ack = !rst || !th->ack;
911 t1->rst = rst;
912 t1->window = htons(win);
913
914 topt = (__be32 *)(t1 + 1);
915
916 if (tsecr) {
917 *topt++ = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
918 (TCPOPT_TIMESTAMP << 8) | TCPOLEN_TIMESTAMP);
919 *topt++ = htonl(tsval);
920 *topt++ = htonl(tsecr);
921 }
922
923 if (mrst)
924 *topt++ = mrst;
925
926#ifdef CONFIG_TCP_MD5SIG
927 if (tcp_key_is_md5(key)) {
928 *topt++ = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
929 (TCPOPT_MD5SIG << 8) | TCPOLEN_MD5SIG);
930 tcp_v6_md5_hash_hdr((__u8 *)topt, key->md5_key,
931 &ipv6_hdr(skb)->saddr,
932 &ipv6_hdr(skb)->daddr, t1);
933 }
934#endif
935#ifdef CONFIG_TCP_AO
936 if (tcp_key_is_ao(key)) {
937 *topt++ = htonl((TCPOPT_AO << 24) |
938 (tcp_ao_len(key->ao_key) << 16) |
939 (key->ao_key->sndid << 8) |
940 (key->rcv_next));
941
942 tcp_ao_hash_hdr(AF_INET6, (char *)topt, key->ao_key,
943 key->traffic_key,
944 (union tcp_ao_addr *)&ipv6_hdr(skb)->saddr,
945 (union tcp_ao_addr *)&ipv6_hdr(skb)->daddr,
946 t1, key->sne);
947 }
948#endif
949
950 memset(&fl6, 0, sizeof(fl6));
951 fl6.daddr = ipv6_hdr(skb)->saddr;
952 fl6.saddr = ipv6_hdr(skb)->daddr;
953 fl6.flowlabel = label;
954
955 buff->ip_summed = CHECKSUM_PARTIAL;
956
957 __tcp_v6_send_check(buff, &fl6.saddr, &fl6.daddr);
958
959 fl6.flowi6_proto = IPPROTO_TCP;
960 if (rt6_need_strict(&fl6.daddr) && !oif)
961 fl6.flowi6_oif = tcp_v6_iif(skb);
962 else {
963 if (!oif && netif_index_is_l3_master(net, skb->skb_iif))
964 oif = skb->skb_iif;
965
966 fl6.flowi6_oif = oif;
967 }
968
969 if (sk) {
970 if (sk->sk_state == TCP_TIME_WAIT)
971 mark = inet_twsk(sk)->tw_mark;
972 else
973 mark = READ_ONCE(sk->sk_mark);
974 skb_set_delivery_time(buff, tcp_transmit_time(sk), true);
975 }
976 if (txhash) {
977 /* autoflowlabel/skb_get_hash_flowi6 rely on buff->hash */
978 skb_set_hash(buff, txhash, PKT_HASH_TYPE_L4);
979 }
980 fl6.flowi6_mark = IP6_REPLY_MARK(net, skb->mark) ?: mark;
981 fl6.fl6_dport = t1->dest;
982 fl6.fl6_sport = t1->source;
983 fl6.flowi6_uid = sock_net_uid(net, sk && sk_fullsock(sk) ? sk : NULL);
984 security_skb_classify_flow(skb, flowi6_to_flowi_common(&fl6));
985
986 /* Pass a socket to ip6_dst_lookup either it is for RST
987 * Underlying function will use this to retrieve the network
988 * namespace
989 */
990 if (sk && sk->sk_state != TCP_TIME_WAIT)
991 dst = ip6_dst_lookup_flow(net, sk, &fl6, NULL); /*sk's xfrm_policy can be referred*/
992 else
993 dst = ip6_dst_lookup_flow(net, ctl_sk, &fl6, NULL);
994 if (!IS_ERR(dst)) {
995 skb_dst_set(buff, dst);
996 ip6_xmit(ctl_sk, buff, &fl6, fl6.flowi6_mark, NULL,
997 tclass & ~INET_ECN_MASK, priority);
998 TCP_INC_STATS(net, TCP_MIB_OUTSEGS);
999 if (rst)
1000 TCP_INC_STATS(net, TCP_MIB_OUTRSTS);
1001 return;
1002 }
1003
1004 kfree_skb(buff);
1005}
1006
1007static void tcp_v6_send_reset(const struct sock *sk, struct sk_buff *skb)
1008{
1009 const struct tcphdr *th = tcp_hdr(skb);
1010 struct ipv6hdr *ipv6h = ipv6_hdr(skb);
1011 const __u8 *md5_hash_location = NULL;
1012#if defined(CONFIG_TCP_MD5SIG) || defined(CONFIG_TCP_AO)
1013 bool allocated_traffic_key = false;
1014#endif
1015 const struct tcp_ao_hdr *aoh;
1016 struct tcp_key key = {};
1017 u32 seq = 0, ack_seq = 0;
1018 __be32 label = 0;
1019 u32 priority = 0;
1020 struct net *net;
1021 u32 txhash = 0;
1022 int oif = 0;
1023#ifdef CONFIG_TCP_MD5SIG
1024 unsigned char newhash[16];
1025 int genhash;
1026 struct sock *sk1 = NULL;
1027#endif
1028
1029 if (th->rst)
1030 return;
1031
1032 /* If sk not NULL, it means we did a successful lookup and incoming
1033 * route had to be correct. prequeue might have dropped our dst.
1034 */
1035 if (!sk && !ipv6_unicast_destination(skb))
1036 return;
1037
1038 net = sk ? sock_net(sk) : dev_net(skb_dst(skb)->dev);
1039 /* Invalid TCP option size or twice included auth */
1040 if (tcp_parse_auth_options(th, &md5_hash_location, &aoh))
1041 return;
1042#if defined(CONFIG_TCP_MD5SIG) || defined(CONFIG_TCP_AO)
1043 rcu_read_lock();
1044#endif
1045#ifdef CONFIG_TCP_MD5SIG
1046 if (sk && sk_fullsock(sk)) {
1047 int l3index;
1048
1049 /* sdif set, means packet ingressed via a device
1050 * in an L3 domain and inet_iif is set to it.
1051 */
1052 l3index = tcp_v6_sdif(skb) ? tcp_v6_iif_l3_slave(skb) : 0;
1053 key.md5_key = tcp_v6_md5_do_lookup(sk, &ipv6h->saddr, l3index);
1054 if (key.md5_key)
1055 key.type = TCP_KEY_MD5;
1056 } else if (md5_hash_location) {
1057 int dif = tcp_v6_iif_l3_slave(skb);
1058 int sdif = tcp_v6_sdif(skb);
1059 int l3index;
1060
1061 /*
1062 * active side is lost. Try to find listening socket through
1063 * source port, and then find md5 key through listening socket.
1064 * we are not loose security here:
1065 * Incoming packet is checked with md5 hash with finding key,
1066 * no RST generated if md5 hash doesn't match.
1067 */
1068 sk1 = inet6_lookup_listener(net, net->ipv4.tcp_death_row.hashinfo,
1069 NULL, 0, &ipv6h->saddr, th->source,
1070 &ipv6h->daddr, ntohs(th->source),
1071 dif, sdif);
1072 if (!sk1)
1073 goto out;
1074
1075 /* sdif set, means packet ingressed via a device
1076 * in an L3 domain and dif is set to it.
1077 */
1078 l3index = tcp_v6_sdif(skb) ? dif : 0;
1079
1080 key.md5_key = tcp_v6_md5_do_lookup(sk1, &ipv6h->saddr, l3index);
1081 if (!key.md5_key)
1082 goto out;
1083 key.type = TCP_KEY_MD5;
1084
1085 genhash = tcp_v6_md5_hash_skb(newhash, key.md5_key, NULL, skb);
1086 if (genhash || memcmp(md5_hash_location, newhash, 16) != 0)
1087 goto out;
1088 }
1089#endif
1090
1091 if (th->ack)
1092 seq = ntohl(th->ack_seq);
1093 else
1094 ack_seq = ntohl(th->seq) + th->syn + th->fin + skb->len -
1095 (th->doff << 2);
1096
1097#ifdef CONFIG_TCP_AO
1098 if (aoh) {
1099 int l3index;
1100
1101 l3index = tcp_v6_sdif(skb) ? tcp_v6_iif_l3_slave(skb) : 0;
1102 if (tcp_ao_prepare_reset(sk, skb, aoh, l3index, seq,
1103 &key.ao_key, &key.traffic_key,
1104 &allocated_traffic_key,
1105 &key.rcv_next, &key.sne))
1106 goto out;
1107 key.type = TCP_KEY_AO;
1108 }
1109#endif
1110
1111 if (sk) {
1112 oif = sk->sk_bound_dev_if;
1113 if (sk_fullsock(sk)) {
1114 trace_tcp_send_reset(sk, skb);
1115 if (inet6_test_bit(REPFLOW, sk))
1116 label = ip6_flowlabel(ipv6h);
1117 priority = READ_ONCE(sk->sk_priority);
1118 txhash = sk->sk_txhash;
1119 }
1120 if (sk->sk_state == TCP_TIME_WAIT) {
1121 label = cpu_to_be32(inet_twsk(sk)->tw_flowlabel);
1122 priority = inet_twsk(sk)->tw_priority;
1123 txhash = inet_twsk(sk)->tw_txhash;
1124 }
1125 } else {
1126 if (net->ipv6.sysctl.flowlabel_reflect & FLOWLABEL_REFLECT_TCP_RESET)
1127 label = ip6_flowlabel(ipv6h);
1128 }
1129
1130 tcp_v6_send_response(sk, skb, seq, ack_seq, 0, 0, 0, oif, 1,
1131 ipv6_get_dsfield(ipv6h), label, priority, txhash,
1132 &key);
1133
1134#if defined(CONFIG_TCP_MD5SIG) || defined(CONFIG_TCP_AO)
1135out:
1136 if (allocated_traffic_key)
1137 kfree(key.traffic_key);
1138 rcu_read_unlock();
1139#endif
1140}
1141
1142static void tcp_v6_send_ack(const struct sock *sk, struct sk_buff *skb, u32 seq,
1143 u32 ack, u32 win, u32 tsval, u32 tsecr, int oif,
1144 struct tcp_key *key, u8 tclass,
1145 __be32 label, u32 priority, u32 txhash)
1146{
1147 tcp_v6_send_response(sk, skb, seq, ack, win, tsval, tsecr, oif, 0,
1148 tclass, label, priority, txhash, key);
1149}
1150
1151static void tcp_v6_timewait_ack(struct sock *sk, struct sk_buff *skb)
1152{
1153 struct inet_timewait_sock *tw = inet_twsk(sk);
1154 struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
1155 struct tcp_key key = {};
1156#ifdef CONFIG_TCP_AO
1157 struct tcp_ao_info *ao_info;
1158
1159 if (static_branch_unlikely(&tcp_ao_needed.key)) {
1160
1161 /* FIXME: the segment to-be-acked is not verified yet */
1162 ao_info = rcu_dereference(tcptw->ao_info);
1163 if (ao_info) {
1164 const struct tcp_ao_hdr *aoh;
1165
1166 /* Invalid TCP option size or twice included auth */
1167 if (tcp_parse_auth_options(tcp_hdr(skb), NULL, &aoh))
1168 goto out;
1169 if (aoh)
1170 key.ao_key = tcp_ao_established_key(ao_info,
1171 aoh->rnext_keyid, -1);
1172 }
1173 }
1174 if (key.ao_key) {
1175 struct tcp_ao_key *rnext_key;
1176
1177 key.traffic_key = snd_other_key(key.ao_key);
1178 /* rcv_next switches to our rcv_next */
1179 rnext_key = READ_ONCE(ao_info->rnext_key);
1180 key.rcv_next = rnext_key->rcvid;
1181 key.sne = READ_ONCE(ao_info->snd_sne);
1182 key.type = TCP_KEY_AO;
1183#else
1184 if (0) {
1185#endif
1186#ifdef CONFIG_TCP_MD5SIG
1187 } else if (static_branch_unlikely(&tcp_md5_needed.key)) {
1188 key.md5_key = tcp_twsk_md5_key(tcptw);
1189 if (key.md5_key)
1190 key.type = TCP_KEY_MD5;
1191#endif
1192 }
1193
1194 tcp_v6_send_ack(sk, skb, tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
1195 tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
1196 tcp_tw_tsval(tcptw),
1197 tcptw->tw_ts_recent, tw->tw_bound_dev_if, &key,
1198 tw->tw_tclass, cpu_to_be32(tw->tw_flowlabel), tw->tw_priority,
1199 tw->tw_txhash);
1200
1201#ifdef CONFIG_TCP_AO
1202out:
1203#endif
1204 inet_twsk_put(tw);
1205}
1206
1207static void tcp_v6_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb,
1208 struct request_sock *req)
1209{
1210 struct tcp_key key = {};
1211
1212#ifdef CONFIG_TCP_AO
1213 if (static_branch_unlikely(&tcp_ao_needed.key) &&
1214 tcp_rsk_used_ao(req)) {
1215 const struct in6_addr *addr = &ipv6_hdr(skb)->saddr;
1216 const struct tcp_ao_hdr *aoh;
1217 int l3index;
1218
1219 l3index = tcp_v6_sdif(skb) ? tcp_v6_iif_l3_slave(skb) : 0;
1220 /* Invalid TCP option size or twice included auth */
1221 if (tcp_parse_auth_options(tcp_hdr(skb), NULL, &aoh))
1222 return;
1223 if (!aoh)
1224 return;
1225 key.ao_key = tcp_ao_do_lookup(sk, l3index,
1226 (union tcp_ao_addr *)addr,
1227 AF_INET6, aoh->rnext_keyid, -1);
1228 if (unlikely(!key.ao_key)) {
1229 /* Send ACK with any matching MKT for the peer */
1230 key.ao_key = tcp_ao_do_lookup(sk, l3index,
1231 (union tcp_ao_addr *)addr,
1232 AF_INET6, -1, -1);
1233 /* Matching key disappeared (user removed the key?)
1234 * let the handshake timeout.
1235 */
1236 if (!key.ao_key) {
1237 net_info_ratelimited("TCP-AO key for (%pI6, %d)->(%pI6, %d) suddenly disappeared, won't ACK new connection\n",
1238 addr,
1239 ntohs(tcp_hdr(skb)->source),
1240 &ipv6_hdr(skb)->daddr,
1241 ntohs(tcp_hdr(skb)->dest));
1242 return;
1243 }
1244 }
1245 key.traffic_key = kmalloc(tcp_ao_digest_size(key.ao_key), GFP_ATOMIC);
1246 if (!key.traffic_key)
1247 return;
1248
1249 key.type = TCP_KEY_AO;
1250 key.rcv_next = aoh->keyid;
1251 tcp_v6_ao_calc_key_rsk(key.ao_key, key.traffic_key, req);
1252#else
1253 if (0) {
1254#endif
1255#ifdef CONFIG_TCP_MD5SIG
1256 } else if (static_branch_unlikely(&tcp_md5_needed.key)) {
1257 int l3index = tcp_v6_sdif(skb) ? tcp_v6_iif_l3_slave(skb) : 0;
1258
1259 key.md5_key = tcp_v6_md5_do_lookup(sk, &ipv6_hdr(skb)->saddr,
1260 l3index);
1261 if (key.md5_key)
1262 key.type = TCP_KEY_MD5;
1263#endif
1264 }
1265
1266 /* sk->sk_state == TCP_LISTEN -> for regular TCP_SYN_RECV
1267 * sk->sk_state == TCP_SYN_RECV -> for Fast Open.
1268 */
1269 /* RFC 7323 2.3
1270 * The window field (SEG.WND) of every outgoing segment, with the
1271 * exception of <SYN> segments, MUST be right-shifted by
1272 * Rcv.Wind.Shift bits:
1273 */
1274 tcp_v6_send_ack(sk, skb, (sk->sk_state == TCP_LISTEN) ?
1275 tcp_rsk(req)->snt_isn + 1 : tcp_sk(sk)->snd_nxt,
1276 tcp_rsk(req)->rcv_nxt,
1277 req->rsk_rcv_wnd >> inet_rsk(req)->rcv_wscale,
1278 tcp_rsk_tsval(tcp_rsk(req)),
1279 READ_ONCE(req->ts_recent), sk->sk_bound_dev_if,
1280 &key, ipv6_get_dsfield(ipv6_hdr(skb)), 0,
1281 READ_ONCE(sk->sk_priority),
1282 READ_ONCE(tcp_rsk(req)->txhash));
1283 if (tcp_key_is_ao(&key))
1284 kfree(key.traffic_key);
1285}
1286
1287
1288static struct sock *tcp_v6_cookie_check(struct sock *sk, struct sk_buff *skb)
1289{
1290#ifdef CONFIG_SYN_COOKIES
1291 const struct tcphdr *th = tcp_hdr(skb);
1292
1293 if (!th->syn)
1294 sk = cookie_v6_check(sk, skb);
1295#endif
1296 return sk;
1297}
1298
1299u16 tcp_v6_get_syncookie(struct sock *sk, struct ipv6hdr *iph,
1300 struct tcphdr *th, u32 *cookie)
1301{
1302 u16 mss = 0;
1303#ifdef CONFIG_SYN_COOKIES
1304 mss = tcp_get_syncookie_mss(&tcp6_request_sock_ops,
1305 &tcp_request_sock_ipv6_ops, sk, th);
1306 if (mss) {
1307 *cookie = __cookie_v6_init_sequence(iph, th, &mss);
1308 tcp_synq_overflow(sk);
1309 }
1310#endif
1311 return mss;
1312}
1313
1314static int tcp_v6_conn_request(struct sock *sk, struct sk_buff *skb)
1315{
1316 if (skb->protocol == htons(ETH_P_IP))
1317 return tcp_v4_conn_request(sk, skb);
1318
1319 if (!ipv6_unicast_destination(skb))
1320 goto drop;
1321
1322 if (ipv6_addr_v4mapped(&ipv6_hdr(skb)->saddr)) {
1323 __IP6_INC_STATS(sock_net(sk), NULL, IPSTATS_MIB_INHDRERRORS);
1324 return 0;
1325 }
1326
1327 return tcp_conn_request(&tcp6_request_sock_ops,
1328 &tcp_request_sock_ipv6_ops, sk, skb);
1329
1330drop:
1331 tcp_listendrop(sk);
1332 return 0; /* don't send reset */
1333}
1334
1335static void tcp_v6_restore_cb(struct sk_buff *skb)
1336{
1337 /* We need to move header back to the beginning if xfrm6_policy_check()
1338 * and tcp_v6_fill_cb() are going to be called again.
1339 * ip6_datagram_recv_specific_ctl() also expects IP6CB to be there.
1340 */
1341 memmove(IP6CB(skb), &TCP_SKB_CB(skb)->header.h6,
1342 sizeof(struct inet6_skb_parm));
1343}
1344
1345static struct sock *tcp_v6_syn_recv_sock(const struct sock *sk, struct sk_buff *skb,
1346 struct request_sock *req,
1347 struct dst_entry *dst,
1348 struct request_sock *req_unhash,
1349 bool *own_req)
1350{
1351 struct inet_request_sock *ireq;
1352 struct ipv6_pinfo *newnp;
1353 const struct ipv6_pinfo *np = tcp_inet6_sk(sk);
1354 struct ipv6_txoptions *opt;
1355 struct inet_sock *newinet;
1356 bool found_dup_sk = false;
1357 struct tcp_sock *newtp;
1358 struct sock *newsk;
1359#ifdef CONFIG_TCP_MD5SIG
1360 struct tcp_md5sig_key *key;
1361 int l3index;
1362#endif
1363 struct flowi6 fl6;
1364
1365 if (skb->protocol == htons(ETH_P_IP)) {
1366 /*
1367 * v6 mapped
1368 */
1369
1370 newsk = tcp_v4_syn_recv_sock(sk, skb, req, dst,
1371 req_unhash, own_req);
1372
1373 if (!newsk)
1374 return NULL;
1375
1376 inet_sk(newsk)->pinet6 = tcp_inet6_sk(newsk);
1377
1378 newnp = tcp_inet6_sk(newsk);
1379 newtp = tcp_sk(newsk);
1380
1381 memcpy(newnp, np, sizeof(struct ipv6_pinfo));
1382
1383 newnp->saddr = newsk->sk_v6_rcv_saddr;
1384
1385 inet_csk(newsk)->icsk_af_ops = &ipv6_mapped;
1386 if (sk_is_mptcp(newsk))
1387 mptcpv6_handle_mapped(newsk, true);
1388 newsk->sk_backlog_rcv = tcp_v4_do_rcv;
1389#if defined(CONFIG_TCP_MD5SIG) || defined(CONFIG_TCP_AO)
1390 newtp->af_specific = &tcp_sock_ipv6_mapped_specific;
1391#endif
1392
1393 newnp->ipv6_mc_list = NULL;
1394 newnp->ipv6_ac_list = NULL;
1395 newnp->ipv6_fl_list = NULL;
1396 newnp->pktoptions = NULL;
1397 newnp->opt = NULL;
1398 newnp->mcast_oif = inet_iif(skb);
1399 newnp->mcast_hops = ip_hdr(skb)->ttl;
1400 newnp->rcv_flowinfo = 0;
1401 if (inet6_test_bit(REPFLOW, sk))
1402 newnp->flow_label = 0;
1403
1404 /*
1405 * No need to charge this sock to the relevant IPv6 refcnt debug socks count
1406 * here, tcp_create_openreq_child now does this for us, see the comment in
1407 * that function for the gory details. -acme
1408 */
1409
1410 /* It is tricky place. Until this moment IPv4 tcp
1411 worked with IPv6 icsk.icsk_af_ops.
1412 Sync it now.
1413 */
1414 tcp_sync_mss(newsk, inet_csk(newsk)->icsk_pmtu_cookie);
1415
1416 return newsk;
1417 }
1418
1419 ireq = inet_rsk(req);
1420
1421 if (sk_acceptq_is_full(sk))
1422 goto out_overflow;
1423
1424 if (!dst) {
1425 dst = inet6_csk_route_req(sk, &fl6, req, IPPROTO_TCP);
1426 if (!dst)
1427 goto out;
1428 }
1429
1430 newsk = tcp_create_openreq_child(sk, req, skb);
1431 if (!newsk)
1432 goto out_nonewsk;
1433
1434 /*
1435 * No need to charge this sock to the relevant IPv6 refcnt debug socks
1436 * count here, tcp_create_openreq_child now does this for us, see the
1437 * comment in that function for the gory details. -acme
1438 */
1439
1440 newsk->sk_gso_type = SKB_GSO_TCPV6;
1441 ip6_dst_store(newsk, dst, NULL, NULL);
1442 inet6_sk_rx_dst_set(newsk, skb);
1443
1444 inet_sk(newsk)->pinet6 = tcp_inet6_sk(newsk);
1445
1446 newtp = tcp_sk(newsk);
1447 newinet = inet_sk(newsk);
1448 newnp = tcp_inet6_sk(newsk);
1449
1450 memcpy(newnp, np, sizeof(struct ipv6_pinfo));
1451
1452 newsk->sk_v6_daddr = ireq->ir_v6_rmt_addr;
1453 newnp->saddr = ireq->ir_v6_loc_addr;
1454 newsk->sk_v6_rcv_saddr = ireq->ir_v6_loc_addr;
1455 newsk->sk_bound_dev_if = ireq->ir_iif;
1456
1457 /* Now IPv6 options...
1458
1459 First: no IPv4 options.
1460 */
1461 newinet->inet_opt = NULL;
1462 newnp->ipv6_mc_list = NULL;
1463 newnp->ipv6_ac_list = NULL;
1464 newnp->ipv6_fl_list = NULL;
1465
1466 /* Clone RX bits */
1467 newnp->rxopt.all = np->rxopt.all;
1468
1469 newnp->pktoptions = NULL;
1470 newnp->opt = NULL;
1471 newnp->mcast_oif = tcp_v6_iif(skb);
1472 newnp->mcast_hops = ipv6_hdr(skb)->hop_limit;
1473 newnp->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(skb));
1474 if (inet6_test_bit(REPFLOW, sk))
1475 newnp->flow_label = ip6_flowlabel(ipv6_hdr(skb));
1476
1477 /* Set ToS of the new socket based upon the value of incoming SYN.
1478 * ECT bits are set later in tcp_init_transfer().
1479 */
1480 if (READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_reflect_tos))
1481 newnp->tclass = tcp_rsk(req)->syn_tos & ~INET_ECN_MASK;
1482
1483 /* Clone native IPv6 options from listening socket (if any)
1484
1485 Yes, keeping reference count would be much more clever,
1486 but we make one more one thing there: reattach optmem
1487 to newsk.
1488 */
1489 opt = ireq->ipv6_opt;
1490 if (!opt)
1491 opt = rcu_dereference(np->opt);
1492 if (opt) {
1493 opt = ipv6_dup_options(newsk, opt);
1494 RCU_INIT_POINTER(newnp->opt, opt);
1495 }
1496 inet_csk(newsk)->icsk_ext_hdr_len = 0;
1497 if (opt)
1498 inet_csk(newsk)->icsk_ext_hdr_len = opt->opt_nflen +
1499 opt->opt_flen;
1500
1501 tcp_ca_openreq_child(newsk, dst);
1502
1503 tcp_sync_mss(newsk, dst_mtu(dst));
1504 newtp->advmss = tcp_mss_clamp(tcp_sk(sk), dst_metric_advmss(dst));
1505
1506 tcp_initialize_rcv_mss(newsk);
1507
1508 newinet->inet_daddr = newinet->inet_saddr = LOOPBACK4_IPV6;
1509 newinet->inet_rcv_saddr = LOOPBACK4_IPV6;
1510
1511#ifdef CONFIG_TCP_MD5SIG
1512 l3index = l3mdev_master_ifindex_by_index(sock_net(sk), ireq->ir_iif);
1513
1514 if (!tcp_rsk_used_ao(req)) {
1515 /* Copy over the MD5 key from the original socket */
1516 key = tcp_v6_md5_do_lookup(sk, &newsk->sk_v6_daddr, l3index);
1517 if (key) {
1518 const union tcp_md5_addr *addr;
1519
1520 addr = (union tcp_md5_addr *)&newsk->sk_v6_daddr;
1521 if (tcp_md5_key_copy(newsk, addr, AF_INET6, 128, l3index, key)) {
1522 inet_csk_prepare_forced_close(newsk);
1523 tcp_done(newsk);
1524 goto out;
1525 }
1526 }
1527 }
1528#endif
1529#ifdef CONFIG_TCP_AO
1530 /* Copy over tcp_ao_info if any */
1531 if (tcp_ao_copy_all_matching(sk, newsk, req, skb, AF_INET6))
1532 goto out; /* OOM */
1533#endif
1534
1535 if (__inet_inherit_port(sk, newsk) < 0) {
1536 inet_csk_prepare_forced_close(newsk);
1537 tcp_done(newsk);
1538 goto out;
1539 }
1540 *own_req = inet_ehash_nolisten(newsk, req_to_sk(req_unhash),
1541 &found_dup_sk);
1542 if (*own_req) {
1543 tcp_move_syn(newtp, req);
1544
1545 /* Clone pktoptions received with SYN, if we own the req */
1546 if (ireq->pktopts) {
1547 newnp->pktoptions = skb_clone_and_charge_r(ireq->pktopts, newsk);
1548 consume_skb(ireq->pktopts);
1549 ireq->pktopts = NULL;
1550 if (newnp->pktoptions)
1551 tcp_v6_restore_cb(newnp->pktoptions);
1552 }
1553 } else {
1554 if (!req_unhash && found_dup_sk) {
1555 /* This code path should only be executed in the
1556 * syncookie case only
1557 */
1558 bh_unlock_sock(newsk);
1559 sock_put(newsk);
1560 newsk = NULL;
1561 }
1562 }
1563
1564 return newsk;
1565
1566out_overflow:
1567 __NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
1568out_nonewsk:
1569 dst_release(dst);
1570out:
1571 tcp_listendrop(sk);
1572 return NULL;
1573}
1574
1575INDIRECT_CALLABLE_DECLARE(struct dst_entry *ipv4_dst_check(struct dst_entry *,
1576 u32));
1577/* The socket must have it's spinlock held when we get
1578 * here, unless it is a TCP_LISTEN socket.
1579 *
1580 * We have a potential double-lock case here, so even when
1581 * doing backlog processing we use the BH locking scheme.
1582 * This is because we cannot sleep with the original spinlock
1583 * held.
1584 */
1585INDIRECT_CALLABLE_SCOPE
1586int tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb)
1587{
1588 struct ipv6_pinfo *np = tcp_inet6_sk(sk);
1589 struct sk_buff *opt_skb = NULL;
1590 enum skb_drop_reason reason;
1591 struct tcp_sock *tp;
1592
1593 /* Imagine: socket is IPv6. IPv4 packet arrives,
1594 goes to IPv4 receive handler and backlogged.
1595 From backlog it always goes here. Kerboom...
1596 Fortunately, tcp_rcv_established and rcv_established
1597 handle them correctly, but it is not case with
1598 tcp_v6_hnd_req and tcp_v6_send_reset(). --ANK
1599 */
1600
1601 if (skb->protocol == htons(ETH_P_IP))
1602 return tcp_v4_do_rcv(sk, skb);
1603
1604 /*
1605 * socket locking is here for SMP purposes as backlog rcv
1606 * is currently called with bh processing disabled.
1607 */
1608
1609 /* Do Stevens' IPV6_PKTOPTIONS.
1610
1611 Yes, guys, it is the only place in our code, where we
1612 may make it not affecting IPv4.
1613 The rest of code is protocol independent,
1614 and I do not like idea to uglify IPv4.
1615
1616 Actually, all the idea behind IPV6_PKTOPTIONS
1617 looks not very well thought. For now we latch
1618 options, received in the last packet, enqueued
1619 by tcp. Feel free to propose better solution.
1620 --ANK (980728)
1621 */
1622 if (np->rxopt.all)
1623 opt_skb = skb_clone_and_charge_r(skb, sk);
1624
1625 if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
1626 struct dst_entry *dst;
1627
1628 dst = rcu_dereference_protected(sk->sk_rx_dst,
1629 lockdep_sock_is_held(sk));
1630
1631 sock_rps_save_rxhash(sk, skb);
1632 sk_mark_napi_id(sk, skb);
1633 if (dst) {
1634 if (sk->sk_rx_dst_ifindex != skb->skb_iif ||
1635 INDIRECT_CALL_1(dst->ops->check, ip6_dst_check,
1636 dst, sk->sk_rx_dst_cookie) == NULL) {
1637 RCU_INIT_POINTER(sk->sk_rx_dst, NULL);
1638 dst_release(dst);
1639 }
1640 }
1641
1642 tcp_rcv_established(sk, skb);
1643 if (opt_skb)
1644 goto ipv6_pktoptions;
1645 return 0;
1646 }
1647
1648 if (tcp_checksum_complete(skb))
1649 goto csum_err;
1650
1651 if (sk->sk_state == TCP_LISTEN) {
1652 struct sock *nsk = tcp_v6_cookie_check(sk, skb);
1653
1654 if (nsk != sk) {
1655 if (nsk) {
1656 reason = tcp_child_process(sk, nsk, skb);
1657 if (reason)
1658 goto reset;
1659 }
1660 if (opt_skb)
1661 __kfree_skb(opt_skb);
1662 return 0;
1663 }
1664 } else
1665 sock_rps_save_rxhash(sk, skb);
1666
1667 reason = tcp_rcv_state_process(sk, skb);
1668 if (reason)
1669 goto reset;
1670 if (opt_skb)
1671 goto ipv6_pktoptions;
1672 return 0;
1673
1674reset:
1675 tcp_v6_send_reset(sk, skb);
1676discard:
1677 if (opt_skb)
1678 __kfree_skb(opt_skb);
1679 kfree_skb_reason(skb, reason);
1680 return 0;
1681csum_err:
1682 reason = SKB_DROP_REASON_TCP_CSUM;
1683 trace_tcp_bad_csum(skb);
1684 TCP_INC_STATS(sock_net(sk), TCP_MIB_CSUMERRORS);
1685 TCP_INC_STATS(sock_net(sk), TCP_MIB_INERRS);
1686 goto discard;
1687
1688
1689ipv6_pktoptions:
1690 /* Do you ask, what is it?
1691
1692 1. skb was enqueued by tcp.
1693 2. skb is added to tail of read queue, rather than out of order.
1694 3. socket is not in passive state.
1695 4. Finally, it really contains options, which user wants to receive.
1696 */
1697 tp = tcp_sk(sk);
1698 if (TCP_SKB_CB(opt_skb)->end_seq == tp->rcv_nxt &&
1699 !((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN))) {
1700 if (np->rxopt.bits.rxinfo || np->rxopt.bits.rxoinfo)
1701 WRITE_ONCE(np->mcast_oif, tcp_v6_iif(opt_skb));
1702 if (np->rxopt.bits.rxhlim || np->rxopt.bits.rxohlim)
1703 WRITE_ONCE(np->mcast_hops,
1704 ipv6_hdr(opt_skb)->hop_limit);
1705 if (np->rxopt.bits.rxflow || np->rxopt.bits.rxtclass)
1706 np->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(opt_skb));
1707 if (inet6_test_bit(REPFLOW, sk))
1708 np->flow_label = ip6_flowlabel(ipv6_hdr(opt_skb));
1709 if (ipv6_opt_accepted(sk, opt_skb, &TCP_SKB_CB(opt_skb)->header.h6)) {
1710 tcp_v6_restore_cb(opt_skb);
1711 opt_skb = xchg(&np->pktoptions, opt_skb);
1712 } else {
1713 __kfree_skb(opt_skb);
1714 opt_skb = xchg(&np->pktoptions, NULL);
1715 }
1716 }
1717
1718 consume_skb(opt_skb);
1719 return 0;
1720}
1721
1722static void tcp_v6_fill_cb(struct sk_buff *skb, const struct ipv6hdr *hdr,
1723 const struct tcphdr *th)
1724{
1725 /* This is tricky: we move IP6CB at its correct location into
1726 * TCP_SKB_CB(). It must be done after xfrm6_policy_check(), because
1727 * _decode_session6() uses IP6CB().
1728 * barrier() makes sure compiler won't play aliasing games.
1729 */
1730 memmove(&TCP_SKB_CB(skb)->header.h6, IP6CB(skb),
1731 sizeof(struct inet6_skb_parm));
1732 barrier();
1733
1734 TCP_SKB_CB(skb)->seq = ntohl(th->seq);
1735 TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
1736 skb->len - th->doff*4);
1737 TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
1738 TCP_SKB_CB(skb)->tcp_flags = tcp_flag_byte(th);
1739 TCP_SKB_CB(skb)->tcp_tw_isn = 0;
1740 TCP_SKB_CB(skb)->ip_dsfield = ipv6_get_dsfield(hdr);
1741 TCP_SKB_CB(skb)->sacked = 0;
1742 TCP_SKB_CB(skb)->has_rxtstamp =
1743 skb->tstamp || skb_hwtstamps(skb)->hwtstamp;
1744}
1745
1746INDIRECT_CALLABLE_SCOPE int tcp_v6_rcv(struct sk_buff *skb)
1747{
1748 enum skb_drop_reason drop_reason;
1749 int sdif = inet6_sdif(skb);
1750 int dif = inet6_iif(skb);
1751 const struct tcphdr *th;
1752 const struct ipv6hdr *hdr;
1753 bool refcounted;
1754 struct sock *sk;
1755 int ret;
1756 struct net *net = dev_net(skb->dev);
1757
1758 drop_reason = SKB_DROP_REASON_NOT_SPECIFIED;
1759 if (skb->pkt_type != PACKET_HOST)
1760 goto discard_it;
1761
1762 /*
1763 * Count it even if it's bad.
1764 */
1765 __TCP_INC_STATS(net, TCP_MIB_INSEGS);
1766
1767 if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
1768 goto discard_it;
1769
1770 th = (const struct tcphdr *)skb->data;
1771
1772 if (unlikely(th->doff < sizeof(struct tcphdr) / 4)) {
1773 drop_reason = SKB_DROP_REASON_PKT_TOO_SMALL;
1774 goto bad_packet;
1775 }
1776 if (!pskb_may_pull(skb, th->doff*4))
1777 goto discard_it;
1778
1779 if (skb_checksum_init(skb, IPPROTO_TCP, ip6_compute_pseudo))
1780 goto csum_error;
1781
1782 th = (const struct tcphdr *)skb->data;
1783 hdr = ipv6_hdr(skb);
1784
1785lookup:
1786 sk = __inet6_lookup_skb(net->ipv4.tcp_death_row.hashinfo, skb, __tcp_hdrlen(th),
1787 th->source, th->dest, inet6_iif(skb), sdif,
1788 &refcounted);
1789 if (!sk)
1790 goto no_tcp_socket;
1791
1792process:
1793 if (sk->sk_state == TCP_TIME_WAIT)
1794 goto do_time_wait;
1795
1796 if (sk->sk_state == TCP_NEW_SYN_RECV) {
1797 struct request_sock *req = inet_reqsk(sk);
1798 bool req_stolen = false;
1799 struct sock *nsk;
1800
1801 sk = req->rsk_listener;
1802 if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb))
1803 drop_reason = SKB_DROP_REASON_XFRM_POLICY;
1804 else
1805 drop_reason = tcp_inbound_hash(sk, req, skb,
1806 &hdr->saddr, &hdr->daddr,
1807 AF_INET6, dif, sdif);
1808 if (drop_reason) {
1809 sk_drops_add(sk, skb);
1810 reqsk_put(req);
1811 goto discard_it;
1812 }
1813 if (tcp_checksum_complete(skb)) {
1814 reqsk_put(req);
1815 goto csum_error;
1816 }
1817 if (unlikely(sk->sk_state != TCP_LISTEN)) {
1818 nsk = reuseport_migrate_sock(sk, req_to_sk(req), skb);
1819 if (!nsk) {
1820 inet_csk_reqsk_queue_drop_and_put(sk, req);
1821 goto lookup;
1822 }
1823 sk = nsk;
1824 /* reuseport_migrate_sock() has already held one sk_refcnt
1825 * before returning.
1826 */
1827 } else {
1828 sock_hold(sk);
1829 }
1830 refcounted = true;
1831 nsk = NULL;
1832 if (!tcp_filter(sk, skb)) {
1833 th = (const struct tcphdr *)skb->data;
1834 hdr = ipv6_hdr(skb);
1835 tcp_v6_fill_cb(skb, hdr, th);
1836 nsk = tcp_check_req(sk, skb, req, false, &req_stolen);
1837 } else {
1838 drop_reason = SKB_DROP_REASON_SOCKET_FILTER;
1839 }
1840 if (!nsk) {
1841 reqsk_put(req);
1842 if (req_stolen) {
1843 /* Another cpu got exclusive access to req
1844 * and created a full blown socket.
1845 * Try to feed this packet to this socket
1846 * instead of discarding it.
1847 */
1848 tcp_v6_restore_cb(skb);
1849 sock_put(sk);
1850 goto lookup;
1851 }
1852 goto discard_and_relse;
1853 }
1854 nf_reset_ct(skb);
1855 if (nsk == sk) {
1856 reqsk_put(req);
1857 tcp_v6_restore_cb(skb);
1858 } else {
1859 drop_reason = tcp_child_process(sk, nsk, skb);
1860 if (drop_reason) {
1861 tcp_v6_send_reset(nsk, skb);
1862 goto discard_and_relse;
1863 }
1864 sock_put(sk);
1865 return 0;
1866 }
1867 }
1868
1869 if (static_branch_unlikely(&ip6_min_hopcount)) {
1870 /* min_hopcount can be changed concurrently from do_ipv6_setsockopt() */
1871 if (unlikely(hdr->hop_limit < READ_ONCE(tcp_inet6_sk(sk)->min_hopcount))) {
1872 __NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP);
1873 drop_reason = SKB_DROP_REASON_TCP_MINTTL;
1874 goto discard_and_relse;
1875 }
1876 }
1877
1878 if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb)) {
1879 drop_reason = SKB_DROP_REASON_XFRM_POLICY;
1880 goto discard_and_relse;
1881 }
1882
1883 drop_reason = tcp_inbound_hash(sk, NULL, skb, &hdr->saddr, &hdr->daddr,
1884 AF_INET6, dif, sdif);
1885 if (drop_reason)
1886 goto discard_and_relse;
1887
1888 nf_reset_ct(skb);
1889
1890 if (tcp_filter(sk, skb)) {
1891 drop_reason = SKB_DROP_REASON_SOCKET_FILTER;
1892 goto discard_and_relse;
1893 }
1894 th = (const struct tcphdr *)skb->data;
1895 hdr = ipv6_hdr(skb);
1896 tcp_v6_fill_cb(skb, hdr, th);
1897
1898 skb->dev = NULL;
1899
1900 if (sk->sk_state == TCP_LISTEN) {
1901 ret = tcp_v6_do_rcv(sk, skb);
1902 goto put_and_return;
1903 }
1904
1905 sk_incoming_cpu_update(sk);
1906
1907 bh_lock_sock_nested(sk);
1908 tcp_segs_in(tcp_sk(sk), skb);
1909 ret = 0;
1910 if (!sock_owned_by_user(sk)) {
1911 ret = tcp_v6_do_rcv(sk, skb);
1912 } else {
1913 if (tcp_add_backlog(sk, skb, &drop_reason))
1914 goto discard_and_relse;
1915 }
1916 bh_unlock_sock(sk);
1917put_and_return:
1918 if (refcounted)
1919 sock_put(sk);
1920 return ret ? -1 : 0;
1921
1922no_tcp_socket:
1923 drop_reason = SKB_DROP_REASON_NO_SOCKET;
1924 if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb))
1925 goto discard_it;
1926
1927 tcp_v6_fill_cb(skb, hdr, th);
1928
1929 if (tcp_checksum_complete(skb)) {
1930csum_error:
1931 drop_reason = SKB_DROP_REASON_TCP_CSUM;
1932 trace_tcp_bad_csum(skb);
1933 __TCP_INC_STATS(net, TCP_MIB_CSUMERRORS);
1934bad_packet:
1935 __TCP_INC_STATS(net, TCP_MIB_INERRS);
1936 } else {
1937 tcp_v6_send_reset(NULL, skb);
1938 }
1939
1940discard_it:
1941 SKB_DR_OR(drop_reason, NOT_SPECIFIED);
1942 kfree_skb_reason(skb, drop_reason);
1943 return 0;
1944
1945discard_and_relse:
1946 sk_drops_add(sk, skb);
1947 if (refcounted)
1948 sock_put(sk);
1949 goto discard_it;
1950
1951do_time_wait:
1952 if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
1953 drop_reason = SKB_DROP_REASON_XFRM_POLICY;
1954 inet_twsk_put(inet_twsk(sk));
1955 goto discard_it;
1956 }
1957
1958 tcp_v6_fill_cb(skb, hdr, th);
1959
1960 if (tcp_checksum_complete(skb)) {
1961 inet_twsk_put(inet_twsk(sk));
1962 goto csum_error;
1963 }
1964
1965 switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) {
1966 case TCP_TW_SYN:
1967 {
1968 struct sock *sk2;
1969
1970 sk2 = inet6_lookup_listener(net, net->ipv4.tcp_death_row.hashinfo,
1971 skb, __tcp_hdrlen(th),
1972 &ipv6_hdr(skb)->saddr, th->source,
1973 &ipv6_hdr(skb)->daddr,
1974 ntohs(th->dest),
1975 tcp_v6_iif_l3_slave(skb),
1976 sdif);
1977 if (sk2) {
1978 struct inet_timewait_sock *tw = inet_twsk(sk);
1979 inet_twsk_deschedule_put(tw);
1980 sk = sk2;
1981 tcp_v6_restore_cb(skb);
1982 refcounted = false;
1983 goto process;
1984 }
1985 }
1986 /* to ACK */
1987 fallthrough;
1988 case TCP_TW_ACK:
1989 tcp_v6_timewait_ack(sk, skb);
1990 break;
1991 case TCP_TW_RST:
1992 tcp_v6_send_reset(sk, skb);
1993 inet_twsk_deschedule_put(inet_twsk(sk));
1994 goto discard_it;
1995 case TCP_TW_SUCCESS:
1996 ;
1997 }
1998 goto discard_it;
1999}
2000
2001void tcp_v6_early_demux(struct sk_buff *skb)
2002{
2003 struct net *net = dev_net(skb->dev);
2004 const struct ipv6hdr *hdr;
2005 const struct tcphdr *th;
2006 struct sock *sk;
2007
2008 if (skb->pkt_type != PACKET_HOST)
2009 return;
2010
2011 if (!pskb_may_pull(skb, skb_transport_offset(skb) + sizeof(struct tcphdr)))
2012 return;
2013
2014 hdr = ipv6_hdr(skb);
2015 th = tcp_hdr(skb);
2016
2017 if (th->doff < sizeof(struct tcphdr) / 4)
2018 return;
2019
2020 /* Note : We use inet6_iif() here, not tcp_v6_iif() */
2021 sk = __inet6_lookup_established(net, net->ipv4.tcp_death_row.hashinfo,
2022 &hdr->saddr, th->source,
2023 &hdr->daddr, ntohs(th->dest),
2024 inet6_iif(skb), inet6_sdif(skb));
2025 if (sk) {
2026 skb->sk = sk;
2027 skb->destructor = sock_edemux;
2028 if (sk_fullsock(sk)) {
2029 struct dst_entry *dst = rcu_dereference(sk->sk_rx_dst);
2030
2031 if (dst)
2032 dst = dst_check(dst, sk->sk_rx_dst_cookie);
2033 if (dst &&
2034 sk->sk_rx_dst_ifindex == skb->skb_iif)
2035 skb_dst_set_noref(skb, dst);
2036 }
2037 }
2038}
2039
2040static struct timewait_sock_ops tcp6_timewait_sock_ops = {
2041 .twsk_obj_size = sizeof(struct tcp6_timewait_sock),
2042 .twsk_unique = tcp_twsk_unique,
2043 .twsk_destructor = tcp_twsk_destructor,
2044};
2045
2046INDIRECT_CALLABLE_SCOPE void tcp_v6_send_check(struct sock *sk, struct sk_buff *skb)
2047{
2048 __tcp_v6_send_check(skb, &sk->sk_v6_rcv_saddr, &sk->sk_v6_daddr);
2049}
2050
2051const struct inet_connection_sock_af_ops ipv6_specific = {
2052 .queue_xmit = inet6_csk_xmit,
2053 .send_check = tcp_v6_send_check,
2054 .rebuild_header = inet6_sk_rebuild_header,
2055 .sk_rx_dst_set = inet6_sk_rx_dst_set,
2056 .conn_request = tcp_v6_conn_request,
2057 .syn_recv_sock = tcp_v6_syn_recv_sock,
2058 .net_header_len = sizeof(struct ipv6hdr),
2059 .setsockopt = ipv6_setsockopt,
2060 .getsockopt = ipv6_getsockopt,
2061 .addr2sockaddr = inet6_csk_addr2sockaddr,
2062 .sockaddr_len = sizeof(struct sockaddr_in6),
2063 .mtu_reduced = tcp_v6_mtu_reduced,
2064};
2065
2066#if defined(CONFIG_TCP_MD5SIG) || defined(CONFIG_TCP_AO)
2067static const struct tcp_sock_af_ops tcp_sock_ipv6_specific = {
2068#ifdef CONFIG_TCP_MD5SIG
2069 .md5_lookup = tcp_v6_md5_lookup,
2070 .calc_md5_hash = tcp_v6_md5_hash_skb,
2071 .md5_parse = tcp_v6_parse_md5_keys,
2072#endif
2073#ifdef CONFIG_TCP_AO
2074 .ao_lookup = tcp_v6_ao_lookup,
2075 .calc_ao_hash = tcp_v6_ao_hash_skb,
2076 .ao_parse = tcp_v6_parse_ao,
2077 .ao_calc_key_sk = tcp_v6_ao_calc_key_sk,
2078#endif
2079};
2080#endif
2081
2082/*
2083 * TCP over IPv4 via INET6 API
2084 */
2085static const struct inet_connection_sock_af_ops ipv6_mapped = {
2086 .queue_xmit = ip_queue_xmit,
2087 .send_check = tcp_v4_send_check,
2088 .rebuild_header = inet_sk_rebuild_header,
2089 .sk_rx_dst_set = inet_sk_rx_dst_set,
2090 .conn_request = tcp_v6_conn_request,
2091 .syn_recv_sock = tcp_v6_syn_recv_sock,
2092 .net_header_len = sizeof(struct iphdr),
2093 .setsockopt = ipv6_setsockopt,
2094 .getsockopt = ipv6_getsockopt,
2095 .addr2sockaddr = inet6_csk_addr2sockaddr,
2096 .sockaddr_len = sizeof(struct sockaddr_in6),
2097 .mtu_reduced = tcp_v4_mtu_reduced,
2098};
2099
2100#if defined(CONFIG_TCP_MD5SIG) || defined(CONFIG_TCP_AO)
2101static const struct tcp_sock_af_ops tcp_sock_ipv6_mapped_specific = {
2102#ifdef CONFIG_TCP_MD5SIG
2103 .md5_lookup = tcp_v4_md5_lookup,
2104 .calc_md5_hash = tcp_v4_md5_hash_skb,
2105 .md5_parse = tcp_v6_parse_md5_keys,
2106#endif
2107#ifdef CONFIG_TCP_AO
2108 .ao_lookup = tcp_v6_ao_lookup,
2109 .calc_ao_hash = tcp_v4_ao_hash_skb,
2110 .ao_parse = tcp_v6_parse_ao,
2111 .ao_calc_key_sk = tcp_v4_ao_calc_key_sk,
2112#endif
2113};
2114#endif
2115
2116/* NOTE: A lot of things set to zero explicitly by call to
2117 * sk_alloc() so need not be done here.
2118 */
2119static int tcp_v6_init_sock(struct sock *sk)
2120{
2121 struct inet_connection_sock *icsk = inet_csk(sk);
2122
2123 tcp_init_sock(sk);
2124
2125 icsk->icsk_af_ops = &ipv6_specific;
2126
2127#if defined(CONFIG_TCP_MD5SIG) || defined(CONFIG_TCP_AO)
2128 tcp_sk(sk)->af_specific = &tcp_sock_ipv6_specific;
2129#endif
2130
2131 return 0;
2132}
2133
2134#ifdef CONFIG_PROC_FS
2135/* Proc filesystem TCPv6 sock list dumping. */
2136static void get_openreq6(struct seq_file *seq,
2137 const struct request_sock *req, int i)
2138{
2139 long ttd = req->rsk_timer.expires - jiffies;
2140 const struct in6_addr *src = &inet_rsk(req)->ir_v6_loc_addr;
2141 const struct in6_addr *dest = &inet_rsk(req)->ir_v6_rmt_addr;
2142
2143 if (ttd < 0)
2144 ttd = 0;
2145
2146 seq_printf(seq,
2147 "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
2148 "%02X %08X:%08X %02X:%08lX %08X %5u %8d %d %d %pK\n",
2149 i,
2150 src->s6_addr32[0], src->s6_addr32[1],
2151 src->s6_addr32[2], src->s6_addr32[3],
2152 inet_rsk(req)->ir_num,
2153 dest->s6_addr32[0], dest->s6_addr32[1],
2154 dest->s6_addr32[2], dest->s6_addr32[3],
2155 ntohs(inet_rsk(req)->ir_rmt_port),
2156 TCP_SYN_RECV,
2157 0, 0, /* could print option size, but that is af dependent. */
2158 1, /* timers active (only the expire timer) */
2159 jiffies_to_clock_t(ttd),
2160 req->num_timeout,
2161 from_kuid_munged(seq_user_ns(seq),
2162 sock_i_uid(req->rsk_listener)),
2163 0, /* non standard timer */
2164 0, /* open_requests have no inode */
2165 0, req);
2166}
2167
2168static void get_tcp6_sock(struct seq_file *seq, struct sock *sp, int i)
2169{
2170 const struct in6_addr *dest, *src;
2171 __u16 destp, srcp;
2172 int timer_active;
2173 unsigned long timer_expires;
2174 const struct inet_sock *inet = inet_sk(sp);
2175 const struct tcp_sock *tp = tcp_sk(sp);
2176 const struct inet_connection_sock *icsk = inet_csk(sp);
2177 const struct fastopen_queue *fastopenq = &icsk->icsk_accept_queue.fastopenq;
2178 int rx_queue;
2179 int state;
2180
2181 dest = &sp->sk_v6_daddr;
2182 src = &sp->sk_v6_rcv_saddr;
2183 destp = ntohs(inet->inet_dport);
2184 srcp = ntohs(inet->inet_sport);
2185
2186 if (icsk->icsk_pending == ICSK_TIME_RETRANS ||
2187 icsk->icsk_pending == ICSK_TIME_REO_TIMEOUT ||
2188 icsk->icsk_pending == ICSK_TIME_LOSS_PROBE) {
2189 timer_active = 1;
2190 timer_expires = icsk->icsk_timeout;
2191 } else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
2192 timer_active = 4;
2193 timer_expires = icsk->icsk_timeout;
2194 } else if (timer_pending(&sp->sk_timer)) {
2195 timer_active = 2;
2196 timer_expires = sp->sk_timer.expires;
2197 } else {
2198 timer_active = 0;
2199 timer_expires = jiffies;
2200 }
2201
2202 state = inet_sk_state_load(sp);
2203 if (state == TCP_LISTEN)
2204 rx_queue = READ_ONCE(sp->sk_ack_backlog);
2205 else
2206 /* Because we don't lock the socket,
2207 * we might find a transient negative value.
2208 */
2209 rx_queue = max_t(int, READ_ONCE(tp->rcv_nxt) -
2210 READ_ONCE(tp->copied_seq), 0);
2211
2212 seq_printf(seq,
2213 "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
2214 "%02X %08X:%08X %02X:%08lX %08X %5u %8d %lu %d %pK %lu %lu %u %u %d\n",
2215 i,
2216 src->s6_addr32[0], src->s6_addr32[1],
2217 src->s6_addr32[2], src->s6_addr32[3], srcp,
2218 dest->s6_addr32[0], dest->s6_addr32[1],
2219 dest->s6_addr32[2], dest->s6_addr32[3], destp,
2220 state,
2221 READ_ONCE(tp->write_seq) - tp->snd_una,
2222 rx_queue,
2223 timer_active,
2224 jiffies_delta_to_clock_t(timer_expires - jiffies),
2225 icsk->icsk_retransmits,
2226 from_kuid_munged(seq_user_ns(seq), sock_i_uid(sp)),
2227 icsk->icsk_probes_out,
2228 sock_i_ino(sp),
2229 refcount_read(&sp->sk_refcnt), sp,
2230 jiffies_to_clock_t(icsk->icsk_rto),
2231 jiffies_to_clock_t(icsk->icsk_ack.ato),
2232 (icsk->icsk_ack.quick << 1) | inet_csk_in_pingpong_mode(sp),
2233 tcp_snd_cwnd(tp),
2234 state == TCP_LISTEN ?
2235 fastopenq->max_qlen :
2236 (tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh)
2237 );
2238}
2239
2240static void get_timewait6_sock(struct seq_file *seq,
2241 struct inet_timewait_sock *tw, int i)
2242{
2243 long delta = tw->tw_timer.expires - jiffies;
2244 const struct in6_addr *dest, *src;
2245 __u16 destp, srcp;
2246
2247 dest = &tw->tw_v6_daddr;
2248 src = &tw->tw_v6_rcv_saddr;
2249 destp = ntohs(tw->tw_dport);
2250 srcp = ntohs(tw->tw_sport);
2251
2252 seq_printf(seq,
2253 "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
2254 "%02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK\n",
2255 i,
2256 src->s6_addr32[0], src->s6_addr32[1],
2257 src->s6_addr32[2], src->s6_addr32[3], srcp,
2258 dest->s6_addr32[0], dest->s6_addr32[1],
2259 dest->s6_addr32[2], dest->s6_addr32[3], destp,
2260 tw->tw_substate, 0, 0,
2261 3, jiffies_delta_to_clock_t(delta), 0, 0, 0, 0,
2262 refcount_read(&tw->tw_refcnt), tw);
2263}
2264
2265static int tcp6_seq_show(struct seq_file *seq, void *v)
2266{
2267 struct tcp_iter_state *st;
2268 struct sock *sk = v;
2269
2270 if (v == SEQ_START_TOKEN) {
2271 seq_puts(seq,
2272 " sl "
2273 "local_address "
2274 "remote_address "
2275 "st tx_queue rx_queue tr tm->when retrnsmt"
2276 " uid timeout inode\n");
2277 goto out;
2278 }
2279 st = seq->private;
2280
2281 if (sk->sk_state == TCP_TIME_WAIT)
2282 get_timewait6_sock(seq, v, st->num);
2283 else if (sk->sk_state == TCP_NEW_SYN_RECV)
2284 get_openreq6(seq, v, st->num);
2285 else
2286 get_tcp6_sock(seq, v, st->num);
2287out:
2288 return 0;
2289}
2290
2291static const struct seq_operations tcp6_seq_ops = {
2292 .show = tcp6_seq_show,
2293 .start = tcp_seq_start,
2294 .next = tcp_seq_next,
2295 .stop = tcp_seq_stop,
2296};
2297
2298static struct tcp_seq_afinfo tcp6_seq_afinfo = {
2299 .family = AF_INET6,
2300};
2301
2302int __net_init tcp6_proc_init(struct net *net)
2303{
2304 if (!proc_create_net_data("tcp6", 0444, net->proc_net, &tcp6_seq_ops,
2305 sizeof(struct tcp_iter_state), &tcp6_seq_afinfo))
2306 return -ENOMEM;
2307 return 0;
2308}
2309
2310void tcp6_proc_exit(struct net *net)
2311{
2312 remove_proc_entry("tcp6", net->proc_net);
2313}
2314#endif
2315
2316struct proto tcpv6_prot = {
2317 .name = "TCPv6",
2318 .owner = THIS_MODULE,
2319 .close = tcp_close,
2320 .pre_connect = tcp_v6_pre_connect,
2321 .connect = tcp_v6_connect,
2322 .disconnect = tcp_disconnect,
2323 .accept = inet_csk_accept,
2324 .ioctl = tcp_ioctl,
2325 .init = tcp_v6_init_sock,
2326 .destroy = tcp_v4_destroy_sock,
2327 .shutdown = tcp_shutdown,
2328 .setsockopt = tcp_setsockopt,
2329 .getsockopt = tcp_getsockopt,
2330 .bpf_bypass_getsockopt = tcp_bpf_bypass_getsockopt,
2331 .keepalive = tcp_set_keepalive,
2332 .recvmsg = tcp_recvmsg,
2333 .sendmsg = tcp_sendmsg,
2334 .splice_eof = tcp_splice_eof,
2335 .backlog_rcv = tcp_v6_do_rcv,
2336 .release_cb = tcp_release_cb,
2337 .hash = inet6_hash,
2338 .unhash = inet_unhash,
2339 .get_port = inet_csk_get_port,
2340 .put_port = inet_put_port,
2341#ifdef CONFIG_BPF_SYSCALL
2342 .psock_update_sk_prot = tcp_bpf_update_proto,
2343#endif
2344 .enter_memory_pressure = tcp_enter_memory_pressure,
2345 .leave_memory_pressure = tcp_leave_memory_pressure,
2346 .stream_memory_free = tcp_stream_memory_free,
2347 .sockets_allocated = &tcp_sockets_allocated,
2348
2349 .memory_allocated = &tcp_memory_allocated,
2350 .per_cpu_fw_alloc = &tcp_memory_per_cpu_fw_alloc,
2351
2352 .memory_pressure = &tcp_memory_pressure,
2353 .orphan_count = &tcp_orphan_count,
2354 .sysctl_mem = sysctl_tcp_mem,
2355 .sysctl_wmem_offset = offsetof(struct net, ipv4.sysctl_tcp_wmem),
2356 .sysctl_rmem_offset = offsetof(struct net, ipv4.sysctl_tcp_rmem),
2357 .max_header = MAX_TCP_HEADER,
2358 .obj_size = sizeof(struct tcp6_sock),
2359 .ipv6_pinfo_offset = offsetof(struct tcp6_sock, inet6),
2360 .slab_flags = SLAB_TYPESAFE_BY_RCU,
2361 .twsk_prot = &tcp6_timewait_sock_ops,
2362 .rsk_prot = &tcp6_request_sock_ops,
2363 .h.hashinfo = NULL,
2364 .no_autobind = true,
2365 .diag_destroy = tcp_abort,
2366};
2367EXPORT_SYMBOL_GPL(tcpv6_prot);
2368
2369
2370static struct inet_protosw tcpv6_protosw = {
2371 .type = SOCK_STREAM,
2372 .protocol = IPPROTO_TCP,
2373 .prot = &tcpv6_prot,
2374 .ops = &inet6_stream_ops,
2375 .flags = INET_PROTOSW_PERMANENT |
2376 INET_PROTOSW_ICSK,
2377};
2378
2379static int __net_init tcpv6_net_init(struct net *net)
2380{
2381 return inet_ctl_sock_create(&net->ipv6.tcp_sk, PF_INET6,
2382 SOCK_RAW, IPPROTO_TCP, net);
2383}
2384
2385static void __net_exit tcpv6_net_exit(struct net *net)
2386{
2387 inet_ctl_sock_destroy(net->ipv6.tcp_sk);
2388}
2389
2390static void __net_exit tcpv6_net_exit_batch(struct list_head *net_exit_list)
2391{
2392 tcp_twsk_purge(net_exit_list, AF_INET6);
2393}
2394
2395static struct pernet_operations tcpv6_net_ops = {
2396 .init = tcpv6_net_init,
2397 .exit = tcpv6_net_exit,
2398 .exit_batch = tcpv6_net_exit_batch,
2399};
2400
2401int __init tcpv6_init(void)
2402{
2403 int ret;
2404
2405 net_hotdata.tcpv6_protocol = (struct inet6_protocol) {
2406 .handler = tcp_v6_rcv,
2407 .err_handler = tcp_v6_err,
2408 .flags = INET6_PROTO_NOPOLICY | INET6_PROTO_FINAL,
2409 };
2410 ret = inet6_add_protocol(&net_hotdata.tcpv6_protocol, IPPROTO_TCP);
2411 if (ret)
2412 goto out;
2413
2414 /* register inet6 protocol */
2415 ret = inet6_register_protosw(&tcpv6_protosw);
2416 if (ret)
2417 goto out_tcpv6_protocol;
2418
2419 ret = register_pernet_subsys(&tcpv6_net_ops);
2420 if (ret)
2421 goto out_tcpv6_protosw;
2422
2423 ret = mptcpv6_init();
2424 if (ret)
2425 goto out_tcpv6_pernet_subsys;
2426
2427out:
2428 return ret;
2429
2430out_tcpv6_pernet_subsys:
2431 unregister_pernet_subsys(&tcpv6_net_ops);
2432out_tcpv6_protosw:
2433 inet6_unregister_protosw(&tcpv6_protosw);
2434out_tcpv6_protocol:
2435 inet6_del_protocol(&net_hotdata.tcpv6_protocol, IPPROTO_TCP);
2436 goto out;
2437}
2438
2439void tcpv6_exit(void)
2440{
2441 unregister_pernet_subsys(&tcpv6_net_ops);
2442 inet6_unregister_protosw(&tcpv6_protosw);
2443 inet6_del_protocol(&net_hotdata.tcpv6_protocol, IPPROTO_TCP);
2444}