xref: /openbmc/linux/net/ipv6/tcp_ipv6.c (revision 8730046c)
1 /*
2  *	TCP over IPv6
3  *	Linux INET6 implementation
4  *
5  *	Authors:
6  *	Pedro Roque		<roque@di.fc.ul.pt>
7  *
8  *	Based on:
9  *	linux/net/ipv4/tcp.c
10  *	linux/net/ipv4/tcp_input.c
11  *	linux/net/ipv4/tcp_output.c
12  *
13  *	Fixes:
14  *	Hideaki YOSHIFUJI	:	sin6_scope_id support
15  *	YOSHIFUJI Hideaki @USAGI and:	Support IPV6_V6ONLY socket option, which
16  *	Alexey Kuznetsov		allow both IPv4 and IPv6 sockets to bind
17  *					a single port at the same time.
18  *	YOSHIFUJI Hideaki @USAGI:	convert /proc/net/tcp6 to seq_file.
19  *
20  *	This program is free software; you can redistribute it and/or
21  *      modify it under the terms of the GNU General Public License
22  *      as published by the Free Software Foundation; either version
23  *      2 of the License, or (at your option) any later version.
24  */
25 
26 #include <linux/bottom_half.h>
27 #include <linux/module.h>
28 #include <linux/errno.h>
29 #include <linux/types.h>
30 #include <linux/socket.h>
31 #include <linux/sockios.h>
32 #include <linux/net.h>
33 #include <linux/jiffies.h>
34 #include <linux/in.h>
35 #include <linux/in6.h>
36 #include <linux/netdevice.h>
37 #include <linux/init.h>
38 #include <linux/jhash.h>
39 #include <linux/ipsec.h>
40 #include <linux/times.h>
41 #include <linux/slab.h>
42 #include <linux/uaccess.h>
43 #include <linux/ipv6.h>
44 #include <linux/icmpv6.h>
45 #include <linux/random.h>
46 
47 #include <net/tcp.h>
48 #include <net/ndisc.h>
49 #include <net/inet6_hashtables.h>
50 #include <net/inet6_connection_sock.h>
51 #include <net/ipv6.h>
52 #include <net/transp_v6.h>
53 #include <net/addrconf.h>
54 #include <net/ip6_route.h>
55 #include <net/ip6_checksum.h>
56 #include <net/inet_ecn.h>
57 #include <net/protocol.h>
58 #include <net/xfrm.h>
59 #include <net/snmp.h>
60 #include <net/dsfield.h>
61 #include <net/timewait_sock.h>
62 #include <net/inet_common.h>
63 #include <net/secure_seq.h>
64 #include <net/busy_poll.h>
65 
66 #include <linux/proc_fs.h>
67 #include <linux/seq_file.h>
68 
69 #include <crypto/hash.h>
70 #include <linux/scatterlist.h>
71 
72 static void	tcp_v6_send_reset(const struct sock *sk, struct sk_buff *skb);
73 static void	tcp_v6_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb,
74 				      struct request_sock *req);
75 
76 static int	tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb);
77 
78 static const struct inet_connection_sock_af_ops ipv6_mapped;
79 static const struct inet_connection_sock_af_ops ipv6_specific;
80 #ifdef CONFIG_TCP_MD5SIG
81 static const struct tcp_sock_af_ops tcp_sock_ipv6_specific;
82 static const struct tcp_sock_af_ops tcp_sock_ipv6_mapped_specific;
83 #else
84 static struct tcp_md5sig_key *tcp_v6_md5_do_lookup(const struct sock *sk,
85 						   const struct in6_addr *addr)
86 {
87 	return NULL;
88 }
89 #endif
90 
91 static void inet6_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb)
92 {
93 	struct dst_entry *dst = skb_dst(skb);
94 
95 	if (dst && dst_hold_safe(dst)) {
96 		const struct rt6_info *rt = (const struct rt6_info *)dst;
97 
98 		sk->sk_rx_dst = dst;
99 		inet_sk(sk)->rx_dst_ifindex = skb->skb_iif;
100 		inet6_sk(sk)->rx_dst_cookie = rt6_get_cookie(rt);
101 	}
102 }
103 
104 static u32 tcp_v6_init_sequence(const struct sk_buff *skb, u32 *tsoff)
105 {
106 	return secure_tcpv6_sequence_number(ipv6_hdr(skb)->daddr.s6_addr32,
107 					    ipv6_hdr(skb)->saddr.s6_addr32,
108 					    tcp_hdr(skb)->dest,
109 					    tcp_hdr(skb)->source, tsoff);
110 }
111 
112 static int tcp_v6_connect(struct sock *sk, struct sockaddr *uaddr,
113 			  int addr_len)
114 {
115 	struct sockaddr_in6 *usin = (struct sockaddr_in6 *) uaddr;
116 	struct inet_sock *inet = inet_sk(sk);
117 	struct inet_connection_sock *icsk = inet_csk(sk);
118 	struct ipv6_pinfo *np = inet6_sk(sk);
119 	struct tcp_sock *tp = tcp_sk(sk);
120 	struct in6_addr *saddr = NULL, *final_p, final;
121 	struct ipv6_txoptions *opt;
122 	struct flowi6 fl6;
123 	struct dst_entry *dst;
124 	int addr_type;
125 	int err;
126 
127 	if (addr_len < SIN6_LEN_RFC2133)
128 		return -EINVAL;
129 
130 	if (usin->sin6_family != AF_INET6)
131 		return -EAFNOSUPPORT;
132 
133 	memset(&fl6, 0, sizeof(fl6));
134 
135 	if (np->sndflow) {
136 		fl6.flowlabel = usin->sin6_flowinfo&IPV6_FLOWINFO_MASK;
137 		IP6_ECN_flow_init(fl6.flowlabel);
138 		if (fl6.flowlabel&IPV6_FLOWLABEL_MASK) {
139 			struct ip6_flowlabel *flowlabel;
140 			flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
141 			if (!flowlabel)
142 				return -EINVAL;
143 			fl6_sock_release(flowlabel);
144 		}
145 	}
146 
147 	/*
148 	 *	connect() to INADDR_ANY means loopback (BSD'ism).
149 	 */
150 
151 	if (ipv6_addr_any(&usin->sin6_addr))
152 		usin->sin6_addr.s6_addr[15] = 0x1;
153 
154 	addr_type = ipv6_addr_type(&usin->sin6_addr);
155 
156 	if (addr_type & IPV6_ADDR_MULTICAST)
157 		return -ENETUNREACH;
158 
159 	if (addr_type&IPV6_ADDR_LINKLOCAL) {
160 		if (addr_len >= sizeof(struct sockaddr_in6) &&
161 		    usin->sin6_scope_id) {
162 			/* If interface is set while binding, indices
163 			 * must coincide.
164 			 */
165 			if (sk->sk_bound_dev_if &&
166 			    sk->sk_bound_dev_if != usin->sin6_scope_id)
167 				return -EINVAL;
168 
169 			sk->sk_bound_dev_if = usin->sin6_scope_id;
170 		}
171 
172 		/* Connect to link-local address requires an interface */
173 		if (!sk->sk_bound_dev_if)
174 			return -EINVAL;
175 	}
176 
177 	if (tp->rx_opt.ts_recent_stamp &&
178 	    !ipv6_addr_equal(&sk->sk_v6_daddr, &usin->sin6_addr)) {
179 		tp->rx_opt.ts_recent = 0;
180 		tp->rx_opt.ts_recent_stamp = 0;
181 		tp->write_seq = 0;
182 	}
183 
184 	sk->sk_v6_daddr = usin->sin6_addr;
185 	np->flow_label = fl6.flowlabel;
186 
187 	/*
188 	 *	TCP over IPv4
189 	 */
190 
191 	if (addr_type == IPV6_ADDR_MAPPED) {
192 		u32 exthdrlen = icsk->icsk_ext_hdr_len;
193 		struct sockaddr_in sin;
194 
195 		SOCK_DEBUG(sk, "connect: ipv4 mapped\n");
196 
197 		if (__ipv6_only_sock(sk))
198 			return -ENETUNREACH;
199 
200 		sin.sin_family = AF_INET;
201 		sin.sin_port = usin->sin6_port;
202 		sin.sin_addr.s_addr = usin->sin6_addr.s6_addr32[3];
203 
204 		icsk->icsk_af_ops = &ipv6_mapped;
205 		sk->sk_backlog_rcv = tcp_v4_do_rcv;
206 #ifdef CONFIG_TCP_MD5SIG
207 		tp->af_specific = &tcp_sock_ipv6_mapped_specific;
208 #endif
209 
210 		err = tcp_v4_connect(sk, (struct sockaddr *)&sin, sizeof(sin));
211 
212 		if (err) {
213 			icsk->icsk_ext_hdr_len = exthdrlen;
214 			icsk->icsk_af_ops = &ipv6_specific;
215 			sk->sk_backlog_rcv = tcp_v6_do_rcv;
216 #ifdef CONFIG_TCP_MD5SIG
217 			tp->af_specific = &tcp_sock_ipv6_specific;
218 #endif
219 			goto failure;
220 		}
221 		np->saddr = sk->sk_v6_rcv_saddr;
222 
223 		return err;
224 	}
225 
226 	if (!ipv6_addr_any(&sk->sk_v6_rcv_saddr))
227 		saddr = &sk->sk_v6_rcv_saddr;
228 
229 	fl6.flowi6_proto = IPPROTO_TCP;
230 	fl6.daddr = sk->sk_v6_daddr;
231 	fl6.saddr = saddr ? *saddr : np->saddr;
232 	fl6.flowi6_oif = sk->sk_bound_dev_if;
233 	fl6.flowi6_mark = sk->sk_mark;
234 	fl6.fl6_dport = usin->sin6_port;
235 	fl6.fl6_sport = inet->inet_sport;
236 	fl6.flowi6_uid = sk->sk_uid;
237 
238 	opt = rcu_dereference_protected(np->opt, lockdep_sock_is_held(sk));
239 	final_p = fl6_update_dst(&fl6, opt, &final);
240 
241 	security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));
242 
243 	dst = ip6_dst_lookup_flow(sk, &fl6, final_p);
244 	if (IS_ERR(dst)) {
245 		err = PTR_ERR(dst);
246 		goto failure;
247 	}
248 
249 	if (!saddr) {
250 		saddr = &fl6.saddr;
251 		sk->sk_v6_rcv_saddr = *saddr;
252 	}
253 
254 	/* set the source address */
255 	np->saddr = *saddr;
256 	inet->inet_rcv_saddr = LOOPBACK4_IPV6;
257 
258 	sk->sk_gso_type = SKB_GSO_TCPV6;
259 	ip6_dst_store(sk, dst, NULL, NULL);
260 
261 	if (tcp_death_row.sysctl_tw_recycle &&
262 	    !tp->rx_opt.ts_recent_stamp &&
263 	    ipv6_addr_equal(&fl6.daddr, &sk->sk_v6_daddr))
264 		tcp_fetch_timewait_stamp(sk, dst);
265 
266 	icsk->icsk_ext_hdr_len = 0;
267 	if (opt)
268 		icsk->icsk_ext_hdr_len = opt->opt_flen +
269 					 opt->opt_nflen;
270 
271 	tp->rx_opt.mss_clamp = IPV6_MIN_MTU - sizeof(struct tcphdr) - sizeof(struct ipv6hdr);
272 
273 	inet->inet_dport = usin->sin6_port;
274 
275 	tcp_set_state(sk, TCP_SYN_SENT);
276 	err = inet6_hash_connect(&tcp_death_row, sk);
277 	if (err)
278 		goto late_failure;
279 
280 	sk_set_txhash(sk);
281 
282 	if (!tp->write_seq && likely(!tp->repair))
283 		tp->write_seq = secure_tcpv6_sequence_number(np->saddr.s6_addr32,
284 							     sk->sk_v6_daddr.s6_addr32,
285 							     inet->inet_sport,
286 							     inet->inet_dport,
287 							     &tp->tsoffset);
288 
289 	err = tcp_connect(sk);
290 	if (err)
291 		goto late_failure;
292 
293 	return 0;
294 
295 late_failure:
296 	tcp_set_state(sk, TCP_CLOSE);
297 	__sk_dst_reset(sk);
298 failure:
299 	inet->inet_dport = 0;
300 	sk->sk_route_caps = 0;
301 	return err;
302 }
303 
304 static void tcp_v6_mtu_reduced(struct sock *sk)
305 {
306 	struct dst_entry *dst;
307 
308 	if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE))
309 		return;
310 
311 	dst = inet6_csk_update_pmtu(sk, tcp_sk(sk)->mtu_info);
312 	if (!dst)
313 		return;
314 
315 	if (inet_csk(sk)->icsk_pmtu_cookie > dst_mtu(dst)) {
316 		tcp_sync_mss(sk, dst_mtu(dst));
317 		tcp_simple_retransmit(sk);
318 	}
319 }
320 
321 static void tcp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
322 		u8 type, u8 code, int offset, __be32 info)
323 {
324 	const struct ipv6hdr *hdr = (const struct ipv6hdr *)skb->data;
325 	const struct tcphdr *th = (struct tcphdr *)(skb->data+offset);
326 	struct net *net = dev_net(skb->dev);
327 	struct request_sock *fastopen;
328 	struct ipv6_pinfo *np;
329 	struct tcp_sock *tp;
330 	__u32 seq, snd_una;
331 	struct sock *sk;
332 	bool fatal;
333 	int err;
334 
335 	sk = __inet6_lookup_established(net, &tcp_hashinfo,
336 					&hdr->daddr, th->dest,
337 					&hdr->saddr, ntohs(th->source),
338 					skb->dev->ifindex);
339 
340 	if (!sk) {
341 		__ICMP6_INC_STATS(net, __in6_dev_get(skb->dev),
342 				  ICMP6_MIB_INERRORS);
343 		return;
344 	}
345 
346 	if (sk->sk_state == TCP_TIME_WAIT) {
347 		inet_twsk_put(inet_twsk(sk));
348 		return;
349 	}
350 	seq = ntohl(th->seq);
351 	fatal = icmpv6_err_convert(type, code, &err);
352 	if (sk->sk_state == TCP_NEW_SYN_RECV)
353 		return tcp_req_err(sk, seq, fatal);
354 
355 	bh_lock_sock(sk);
356 	if (sock_owned_by_user(sk) && type != ICMPV6_PKT_TOOBIG)
357 		__NET_INC_STATS(net, LINUX_MIB_LOCKDROPPEDICMPS);
358 
359 	if (sk->sk_state == TCP_CLOSE)
360 		goto out;
361 
362 	if (ipv6_hdr(skb)->hop_limit < inet6_sk(sk)->min_hopcount) {
363 		__NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP);
364 		goto out;
365 	}
366 
367 	tp = tcp_sk(sk);
368 	/* XXX (TFO) - tp->snd_una should be ISN (tcp_create_openreq_child() */
369 	fastopen = tp->fastopen_rsk;
370 	snd_una = fastopen ? tcp_rsk(fastopen)->snt_isn : tp->snd_una;
371 	if (sk->sk_state != TCP_LISTEN &&
372 	    !between(seq, snd_una, tp->snd_nxt)) {
373 		__NET_INC_STATS(net, LINUX_MIB_OUTOFWINDOWICMPS);
374 		goto out;
375 	}
376 
377 	np = inet6_sk(sk);
378 
379 	if (type == NDISC_REDIRECT) {
380 		struct dst_entry *dst = __sk_dst_check(sk, np->dst_cookie);
381 
382 		if (dst)
383 			dst->ops->redirect(dst, sk, skb);
384 		goto out;
385 	}
386 
387 	if (type == ICMPV6_PKT_TOOBIG) {
388 		/* We are not interested in TCP_LISTEN and open_requests
389 		 * (SYN-ACKs send out by Linux are always <576bytes so
390 		 * they should go through unfragmented).
391 		 */
392 		if (sk->sk_state == TCP_LISTEN)
393 			goto out;
394 
395 		if (!ip6_sk_accept_pmtu(sk))
396 			goto out;
397 
398 		tp->mtu_info = ntohl(info);
399 		if (!sock_owned_by_user(sk))
400 			tcp_v6_mtu_reduced(sk);
401 		else if (!test_and_set_bit(TCP_MTU_REDUCED_DEFERRED,
402 					   &sk->sk_tsq_flags))
403 			sock_hold(sk);
404 		goto out;
405 	}
406 
407 
408 	/* Might be for an request_sock */
409 	switch (sk->sk_state) {
410 	case TCP_SYN_SENT:
411 	case TCP_SYN_RECV:
412 		/* Only in fast or simultaneous open. If a fast open socket is
413 		 * is already accepted it is treated as a connected one below.
414 		 */
415 		if (fastopen && !fastopen->sk)
416 			break;
417 
418 		if (!sock_owned_by_user(sk)) {
419 			sk->sk_err = err;
420 			sk->sk_error_report(sk);		/* Wake people up to see the error (see connect in sock.c) */
421 
422 			tcp_done(sk);
423 		} else
424 			sk->sk_err_soft = err;
425 		goto out;
426 	}
427 
428 	if (!sock_owned_by_user(sk) && np->recverr) {
429 		sk->sk_err = err;
430 		sk->sk_error_report(sk);
431 	} else
432 		sk->sk_err_soft = err;
433 
434 out:
435 	bh_unlock_sock(sk);
436 	sock_put(sk);
437 }
438 
439 
440 static int tcp_v6_send_synack(const struct sock *sk, struct dst_entry *dst,
441 			      struct flowi *fl,
442 			      struct request_sock *req,
443 			      struct tcp_fastopen_cookie *foc,
444 			      enum tcp_synack_type synack_type)
445 {
446 	struct inet_request_sock *ireq = inet_rsk(req);
447 	struct ipv6_pinfo *np = inet6_sk(sk);
448 	struct ipv6_txoptions *opt;
449 	struct flowi6 *fl6 = &fl->u.ip6;
450 	struct sk_buff *skb;
451 	int err = -ENOMEM;
452 
453 	/* First, grab a route. */
454 	if (!dst && (dst = inet6_csk_route_req(sk, fl6, req,
455 					       IPPROTO_TCP)) == NULL)
456 		goto done;
457 
458 	skb = tcp_make_synack(sk, dst, req, foc, synack_type);
459 
460 	if (skb) {
461 		__tcp_v6_send_check(skb, &ireq->ir_v6_loc_addr,
462 				    &ireq->ir_v6_rmt_addr);
463 
464 		fl6->daddr = ireq->ir_v6_rmt_addr;
465 		if (np->repflow && ireq->pktopts)
466 			fl6->flowlabel = ip6_flowlabel(ipv6_hdr(ireq->pktopts));
467 
468 		rcu_read_lock();
469 		opt = ireq->ipv6_opt;
470 		if (!opt)
471 			opt = rcu_dereference(np->opt);
472 		err = ip6_xmit(sk, skb, fl6, opt, np->tclass);
473 		rcu_read_unlock();
474 		err = net_xmit_eval(err);
475 	}
476 
477 done:
478 	return err;
479 }
480 
481 
482 static void tcp_v6_reqsk_destructor(struct request_sock *req)
483 {
484 	kfree(inet_rsk(req)->ipv6_opt);
485 	kfree_skb(inet_rsk(req)->pktopts);
486 }
487 
488 #ifdef CONFIG_TCP_MD5SIG
489 static struct tcp_md5sig_key *tcp_v6_md5_do_lookup(const struct sock *sk,
490 						   const struct in6_addr *addr)
491 {
492 	return tcp_md5_do_lookup(sk, (union tcp_md5_addr *)addr, AF_INET6);
493 }
494 
495 static struct tcp_md5sig_key *tcp_v6_md5_lookup(const struct sock *sk,
496 						const struct sock *addr_sk)
497 {
498 	return tcp_v6_md5_do_lookup(sk, &addr_sk->sk_v6_daddr);
499 }
500 
501 static int tcp_v6_parse_md5_keys(struct sock *sk, char __user *optval,
502 				 int optlen)
503 {
504 	struct tcp_md5sig cmd;
505 	struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)&cmd.tcpm_addr;
506 
507 	if (optlen < sizeof(cmd))
508 		return -EINVAL;
509 
510 	if (copy_from_user(&cmd, optval, sizeof(cmd)))
511 		return -EFAULT;
512 
513 	if (sin6->sin6_family != AF_INET6)
514 		return -EINVAL;
515 
516 	if (!cmd.tcpm_keylen) {
517 		if (ipv6_addr_v4mapped(&sin6->sin6_addr))
518 			return tcp_md5_do_del(sk, (union tcp_md5_addr *)&sin6->sin6_addr.s6_addr32[3],
519 					      AF_INET);
520 		return tcp_md5_do_del(sk, (union tcp_md5_addr *)&sin6->sin6_addr,
521 				      AF_INET6);
522 	}
523 
524 	if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN)
525 		return -EINVAL;
526 
527 	if (ipv6_addr_v4mapped(&sin6->sin6_addr))
528 		return tcp_md5_do_add(sk, (union tcp_md5_addr *)&sin6->sin6_addr.s6_addr32[3],
529 				      AF_INET, cmd.tcpm_key, cmd.tcpm_keylen, GFP_KERNEL);
530 
531 	return tcp_md5_do_add(sk, (union tcp_md5_addr *)&sin6->sin6_addr,
532 			      AF_INET6, cmd.tcpm_key, cmd.tcpm_keylen, GFP_KERNEL);
533 }
534 
535 static int tcp_v6_md5_hash_headers(struct tcp_md5sig_pool *hp,
536 				   const struct in6_addr *daddr,
537 				   const struct in6_addr *saddr,
538 				   const struct tcphdr *th, int nbytes)
539 {
540 	struct tcp6_pseudohdr *bp;
541 	struct scatterlist sg;
542 	struct tcphdr *_th;
543 
544 	bp = hp->scratch;
545 	/* 1. TCP pseudo-header (RFC2460) */
546 	bp->saddr = *saddr;
547 	bp->daddr = *daddr;
548 	bp->protocol = cpu_to_be32(IPPROTO_TCP);
549 	bp->len = cpu_to_be32(nbytes);
550 
551 	_th = (struct tcphdr *)(bp + 1);
552 	memcpy(_th, th, sizeof(*th));
553 	_th->check = 0;
554 
555 	sg_init_one(&sg, bp, sizeof(*bp) + sizeof(*th));
556 	ahash_request_set_crypt(hp->md5_req, &sg, NULL,
557 				sizeof(*bp) + sizeof(*th));
558 	return crypto_ahash_update(hp->md5_req);
559 }
560 
561 static int tcp_v6_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key,
562 			       const struct in6_addr *daddr, struct in6_addr *saddr,
563 			       const struct tcphdr *th)
564 {
565 	struct tcp_md5sig_pool *hp;
566 	struct ahash_request *req;
567 
568 	hp = tcp_get_md5sig_pool();
569 	if (!hp)
570 		goto clear_hash_noput;
571 	req = hp->md5_req;
572 
573 	if (crypto_ahash_init(req))
574 		goto clear_hash;
575 	if (tcp_v6_md5_hash_headers(hp, daddr, saddr, th, th->doff << 2))
576 		goto clear_hash;
577 	if (tcp_md5_hash_key(hp, key))
578 		goto clear_hash;
579 	ahash_request_set_crypt(req, NULL, md5_hash, 0);
580 	if (crypto_ahash_final(req))
581 		goto clear_hash;
582 
583 	tcp_put_md5sig_pool();
584 	return 0;
585 
586 clear_hash:
587 	tcp_put_md5sig_pool();
588 clear_hash_noput:
589 	memset(md5_hash, 0, 16);
590 	return 1;
591 }
592 
593 static int tcp_v6_md5_hash_skb(char *md5_hash,
594 			       const struct tcp_md5sig_key *key,
595 			       const struct sock *sk,
596 			       const struct sk_buff *skb)
597 {
598 	const struct in6_addr *saddr, *daddr;
599 	struct tcp_md5sig_pool *hp;
600 	struct ahash_request *req;
601 	const struct tcphdr *th = tcp_hdr(skb);
602 
603 	if (sk) { /* valid for establish/request sockets */
604 		saddr = &sk->sk_v6_rcv_saddr;
605 		daddr = &sk->sk_v6_daddr;
606 	} else {
607 		const struct ipv6hdr *ip6h = ipv6_hdr(skb);
608 		saddr = &ip6h->saddr;
609 		daddr = &ip6h->daddr;
610 	}
611 
612 	hp = tcp_get_md5sig_pool();
613 	if (!hp)
614 		goto clear_hash_noput;
615 	req = hp->md5_req;
616 
617 	if (crypto_ahash_init(req))
618 		goto clear_hash;
619 
620 	if (tcp_v6_md5_hash_headers(hp, daddr, saddr, th, skb->len))
621 		goto clear_hash;
622 	if (tcp_md5_hash_skb_data(hp, skb, th->doff << 2))
623 		goto clear_hash;
624 	if (tcp_md5_hash_key(hp, key))
625 		goto clear_hash;
626 	ahash_request_set_crypt(req, NULL, md5_hash, 0);
627 	if (crypto_ahash_final(req))
628 		goto clear_hash;
629 
630 	tcp_put_md5sig_pool();
631 	return 0;
632 
633 clear_hash:
634 	tcp_put_md5sig_pool();
635 clear_hash_noput:
636 	memset(md5_hash, 0, 16);
637 	return 1;
638 }
639 
640 #endif
641 
642 static bool tcp_v6_inbound_md5_hash(const struct sock *sk,
643 				    const struct sk_buff *skb)
644 {
645 #ifdef CONFIG_TCP_MD5SIG
646 	const __u8 *hash_location = NULL;
647 	struct tcp_md5sig_key *hash_expected;
648 	const struct ipv6hdr *ip6h = ipv6_hdr(skb);
649 	const struct tcphdr *th = tcp_hdr(skb);
650 	int genhash;
651 	u8 newhash[16];
652 
653 	hash_expected = tcp_v6_md5_do_lookup(sk, &ip6h->saddr);
654 	hash_location = tcp_parse_md5sig_option(th);
655 
656 	/* We've parsed the options - do we have a hash? */
657 	if (!hash_expected && !hash_location)
658 		return false;
659 
660 	if (hash_expected && !hash_location) {
661 		NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5NOTFOUND);
662 		return true;
663 	}
664 
665 	if (!hash_expected && hash_location) {
666 		NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5UNEXPECTED);
667 		return true;
668 	}
669 
670 	/* check the signature */
671 	genhash = tcp_v6_md5_hash_skb(newhash,
672 				      hash_expected,
673 				      NULL, skb);
674 
675 	if (genhash || memcmp(hash_location, newhash, 16) != 0) {
676 		NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5FAILURE);
677 		net_info_ratelimited("MD5 Hash %s for [%pI6c]:%u->[%pI6c]:%u\n",
678 				     genhash ? "failed" : "mismatch",
679 				     &ip6h->saddr, ntohs(th->source),
680 				     &ip6h->daddr, ntohs(th->dest));
681 		return true;
682 	}
683 #endif
684 	return false;
685 }
686 
687 static void tcp_v6_init_req(struct request_sock *req,
688 			    const struct sock *sk_listener,
689 			    struct sk_buff *skb)
690 {
691 	struct inet_request_sock *ireq = inet_rsk(req);
692 	const struct ipv6_pinfo *np = inet6_sk(sk_listener);
693 
694 	ireq->ir_v6_rmt_addr = ipv6_hdr(skb)->saddr;
695 	ireq->ir_v6_loc_addr = ipv6_hdr(skb)->daddr;
696 
697 	/* So that link locals have meaning */
698 	if (!sk_listener->sk_bound_dev_if &&
699 	    ipv6_addr_type(&ireq->ir_v6_rmt_addr) & IPV6_ADDR_LINKLOCAL)
700 		ireq->ir_iif = tcp_v6_iif(skb);
701 
702 	if (!TCP_SKB_CB(skb)->tcp_tw_isn &&
703 	    (ipv6_opt_accepted(sk_listener, skb, &TCP_SKB_CB(skb)->header.h6) ||
704 	     np->rxopt.bits.rxinfo ||
705 	     np->rxopt.bits.rxoinfo || np->rxopt.bits.rxhlim ||
706 	     np->rxopt.bits.rxohlim || np->repflow)) {
707 		atomic_inc(&skb->users);
708 		ireq->pktopts = skb;
709 	}
710 }
711 
712 static struct dst_entry *tcp_v6_route_req(const struct sock *sk,
713 					  struct flowi *fl,
714 					  const struct request_sock *req,
715 					  bool *strict)
716 {
717 	if (strict)
718 		*strict = true;
719 	return inet6_csk_route_req(sk, &fl->u.ip6, req, IPPROTO_TCP);
720 }
721 
722 struct request_sock_ops tcp6_request_sock_ops __read_mostly = {
723 	.family		=	AF_INET6,
724 	.obj_size	=	sizeof(struct tcp6_request_sock),
725 	.rtx_syn_ack	=	tcp_rtx_synack,
726 	.send_ack	=	tcp_v6_reqsk_send_ack,
727 	.destructor	=	tcp_v6_reqsk_destructor,
728 	.send_reset	=	tcp_v6_send_reset,
729 	.syn_ack_timeout =	tcp_syn_ack_timeout,
730 };
731 
732 static const struct tcp_request_sock_ops tcp_request_sock_ipv6_ops = {
733 	.mss_clamp	=	IPV6_MIN_MTU - sizeof(struct tcphdr) -
734 				sizeof(struct ipv6hdr),
735 #ifdef CONFIG_TCP_MD5SIG
736 	.req_md5_lookup	=	tcp_v6_md5_lookup,
737 	.calc_md5_hash	=	tcp_v6_md5_hash_skb,
738 #endif
739 	.init_req	=	tcp_v6_init_req,
740 #ifdef CONFIG_SYN_COOKIES
741 	.cookie_init_seq =	cookie_v6_init_sequence,
742 #endif
743 	.route_req	=	tcp_v6_route_req,
744 	.init_seq	=	tcp_v6_init_sequence,
745 	.send_synack	=	tcp_v6_send_synack,
746 };
747 
748 static void tcp_v6_send_response(const struct sock *sk, struct sk_buff *skb, u32 seq,
749 				 u32 ack, u32 win, u32 tsval, u32 tsecr,
750 				 int oif, struct tcp_md5sig_key *key, int rst,
751 				 u8 tclass, __be32 label)
752 {
753 	const struct tcphdr *th = tcp_hdr(skb);
754 	struct tcphdr *t1;
755 	struct sk_buff *buff;
756 	struct flowi6 fl6;
757 	struct net *net = sk ? sock_net(sk) : dev_net(skb_dst(skb)->dev);
758 	struct sock *ctl_sk = net->ipv6.tcp_sk;
759 	unsigned int tot_len = sizeof(struct tcphdr);
760 	struct dst_entry *dst;
761 	__be32 *topt;
762 
763 	if (tsecr)
764 		tot_len += TCPOLEN_TSTAMP_ALIGNED;
765 #ifdef CONFIG_TCP_MD5SIG
766 	if (key)
767 		tot_len += TCPOLEN_MD5SIG_ALIGNED;
768 #endif
769 
770 	buff = alloc_skb(MAX_HEADER + sizeof(struct ipv6hdr) + tot_len,
771 			 GFP_ATOMIC);
772 	if (!buff)
773 		return;
774 
775 	skb_reserve(buff, MAX_HEADER + sizeof(struct ipv6hdr) + tot_len);
776 
777 	t1 = (struct tcphdr *) skb_push(buff, tot_len);
778 	skb_reset_transport_header(buff);
779 
780 	/* Swap the send and the receive. */
781 	memset(t1, 0, sizeof(*t1));
782 	t1->dest = th->source;
783 	t1->source = th->dest;
784 	t1->doff = tot_len / 4;
785 	t1->seq = htonl(seq);
786 	t1->ack_seq = htonl(ack);
787 	t1->ack = !rst || !th->ack;
788 	t1->rst = rst;
789 	t1->window = htons(win);
790 
791 	topt = (__be32 *)(t1 + 1);
792 
793 	if (tsecr) {
794 		*topt++ = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
795 				(TCPOPT_TIMESTAMP << 8) | TCPOLEN_TIMESTAMP);
796 		*topt++ = htonl(tsval);
797 		*topt++ = htonl(tsecr);
798 	}
799 
800 #ifdef CONFIG_TCP_MD5SIG
801 	if (key) {
802 		*topt++ = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
803 				(TCPOPT_MD5SIG << 8) | TCPOLEN_MD5SIG);
804 		tcp_v6_md5_hash_hdr((__u8 *)topt, key,
805 				    &ipv6_hdr(skb)->saddr,
806 				    &ipv6_hdr(skb)->daddr, t1);
807 	}
808 #endif
809 
810 	memset(&fl6, 0, sizeof(fl6));
811 	fl6.daddr = ipv6_hdr(skb)->saddr;
812 	fl6.saddr = ipv6_hdr(skb)->daddr;
813 	fl6.flowlabel = label;
814 
815 	buff->ip_summed = CHECKSUM_PARTIAL;
816 	buff->csum = 0;
817 
818 	__tcp_v6_send_check(buff, &fl6.saddr, &fl6.daddr);
819 
820 	fl6.flowi6_proto = IPPROTO_TCP;
821 	if (rt6_need_strict(&fl6.daddr) && !oif)
822 		fl6.flowi6_oif = tcp_v6_iif(skb);
823 	else {
824 		if (!oif && netif_index_is_l3_master(net, skb->skb_iif))
825 			oif = skb->skb_iif;
826 
827 		fl6.flowi6_oif = oif;
828 	}
829 
830 	fl6.flowi6_mark = IP6_REPLY_MARK(net, skb->mark);
831 	fl6.fl6_dport = t1->dest;
832 	fl6.fl6_sport = t1->source;
833 	fl6.flowi6_uid = sock_net_uid(net, sk && sk_fullsock(sk) ? sk : NULL);
834 	security_skb_classify_flow(skb, flowi6_to_flowi(&fl6));
835 
836 	/* Pass a socket to ip6_dst_lookup either it is for RST
837 	 * Underlying function will use this to retrieve the network
838 	 * namespace
839 	 */
840 	dst = ip6_dst_lookup_flow(ctl_sk, &fl6, NULL);
841 	if (!IS_ERR(dst)) {
842 		skb_dst_set(buff, dst);
843 		ip6_xmit(ctl_sk, buff, &fl6, NULL, tclass);
844 		TCP_INC_STATS(net, TCP_MIB_OUTSEGS);
845 		if (rst)
846 			TCP_INC_STATS(net, TCP_MIB_OUTRSTS);
847 		return;
848 	}
849 
850 	kfree_skb(buff);
851 }
852 
853 static void tcp_v6_send_reset(const struct sock *sk, struct sk_buff *skb)
854 {
855 	const struct tcphdr *th = tcp_hdr(skb);
856 	u32 seq = 0, ack_seq = 0;
857 	struct tcp_md5sig_key *key = NULL;
858 #ifdef CONFIG_TCP_MD5SIG
859 	const __u8 *hash_location = NULL;
860 	struct ipv6hdr *ipv6h = ipv6_hdr(skb);
861 	unsigned char newhash[16];
862 	int genhash;
863 	struct sock *sk1 = NULL;
864 #endif
865 	int oif;
866 
867 	if (th->rst)
868 		return;
869 
870 	/* If sk not NULL, it means we did a successful lookup and incoming
871 	 * route had to be correct. prequeue might have dropped our dst.
872 	 */
873 	if (!sk && !ipv6_unicast_destination(skb))
874 		return;
875 
876 #ifdef CONFIG_TCP_MD5SIG
877 	rcu_read_lock();
878 	hash_location = tcp_parse_md5sig_option(th);
879 	if (sk && sk_fullsock(sk)) {
880 		key = tcp_v6_md5_do_lookup(sk, &ipv6h->saddr);
881 	} else if (hash_location) {
882 		/*
883 		 * active side is lost. Try to find listening socket through
884 		 * source port, and then find md5 key through listening socket.
885 		 * we are not loose security here:
886 		 * Incoming packet is checked with md5 hash with finding key,
887 		 * no RST generated if md5 hash doesn't match.
888 		 */
889 		sk1 = inet6_lookup_listener(dev_net(skb_dst(skb)->dev),
890 					   &tcp_hashinfo, NULL, 0,
891 					   &ipv6h->saddr,
892 					   th->source, &ipv6h->daddr,
893 					   ntohs(th->source), tcp_v6_iif(skb));
894 		if (!sk1)
895 			goto out;
896 
897 		key = tcp_v6_md5_do_lookup(sk1, &ipv6h->saddr);
898 		if (!key)
899 			goto out;
900 
901 		genhash = tcp_v6_md5_hash_skb(newhash, key, NULL, skb);
902 		if (genhash || memcmp(hash_location, newhash, 16) != 0)
903 			goto out;
904 	}
905 #endif
906 
907 	if (th->ack)
908 		seq = ntohl(th->ack_seq);
909 	else
910 		ack_seq = ntohl(th->seq) + th->syn + th->fin + skb->len -
911 			  (th->doff << 2);
912 
913 	oif = sk ? sk->sk_bound_dev_if : 0;
914 	tcp_v6_send_response(sk, skb, seq, ack_seq, 0, 0, 0, oif, key, 1, 0, 0);
915 
916 #ifdef CONFIG_TCP_MD5SIG
917 out:
918 	rcu_read_unlock();
919 #endif
920 }
921 
922 static void tcp_v6_send_ack(const struct sock *sk, struct sk_buff *skb, u32 seq,
923 			    u32 ack, u32 win, u32 tsval, u32 tsecr, int oif,
924 			    struct tcp_md5sig_key *key, u8 tclass,
925 			    __be32 label)
926 {
927 	tcp_v6_send_response(sk, skb, seq, ack, win, tsval, tsecr, oif, key, 0,
928 			     tclass, label);
929 }
930 
931 static void tcp_v6_timewait_ack(struct sock *sk, struct sk_buff *skb)
932 {
933 	struct inet_timewait_sock *tw = inet_twsk(sk);
934 	struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
935 
936 	tcp_v6_send_ack(sk, skb, tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
937 			tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
938 			tcp_time_stamp + tcptw->tw_ts_offset,
939 			tcptw->tw_ts_recent, tw->tw_bound_dev_if, tcp_twsk_md5_key(tcptw),
940 			tw->tw_tclass, cpu_to_be32(tw->tw_flowlabel));
941 
942 	inet_twsk_put(tw);
943 }
944 
945 static void tcp_v6_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb,
946 				  struct request_sock *req)
947 {
948 	/* sk->sk_state == TCP_LISTEN -> for regular TCP_SYN_RECV
949 	 * sk->sk_state == TCP_SYN_RECV -> for Fast Open.
950 	 */
951 	/* RFC 7323 2.3
952 	 * The window field (SEG.WND) of every outgoing segment, with the
953 	 * exception of <SYN> segments, MUST be right-shifted by
954 	 * Rcv.Wind.Shift bits:
955 	 */
956 	tcp_v6_send_ack(sk, skb, (sk->sk_state == TCP_LISTEN) ?
957 			tcp_rsk(req)->snt_isn + 1 : tcp_sk(sk)->snd_nxt,
958 			tcp_rsk(req)->rcv_nxt,
959 			req->rsk_rcv_wnd >> inet_rsk(req)->rcv_wscale,
960 			tcp_time_stamp + tcp_rsk(req)->ts_off,
961 			req->ts_recent, sk->sk_bound_dev_if,
962 			tcp_v6_md5_do_lookup(sk, &ipv6_hdr(skb)->daddr),
963 			0, 0);
964 }
965 
966 
967 static struct sock *tcp_v6_cookie_check(struct sock *sk, struct sk_buff *skb)
968 {
969 #ifdef CONFIG_SYN_COOKIES
970 	const struct tcphdr *th = tcp_hdr(skb);
971 
972 	if (!th->syn)
973 		sk = cookie_v6_check(sk, skb);
974 #endif
975 	return sk;
976 }
977 
978 static int tcp_v6_conn_request(struct sock *sk, struct sk_buff *skb)
979 {
980 	if (skb->protocol == htons(ETH_P_IP))
981 		return tcp_v4_conn_request(sk, skb);
982 
983 	if (!ipv6_unicast_destination(skb))
984 		goto drop;
985 
986 	return tcp_conn_request(&tcp6_request_sock_ops,
987 				&tcp_request_sock_ipv6_ops, sk, skb);
988 
989 drop:
990 	tcp_listendrop(sk);
991 	return 0; /* don't send reset */
992 }
993 
994 static struct sock *tcp_v6_syn_recv_sock(const struct sock *sk, struct sk_buff *skb,
995 					 struct request_sock *req,
996 					 struct dst_entry *dst,
997 					 struct request_sock *req_unhash,
998 					 bool *own_req)
999 {
1000 	struct inet_request_sock *ireq;
1001 	struct ipv6_pinfo *newnp;
1002 	const struct ipv6_pinfo *np = inet6_sk(sk);
1003 	struct ipv6_txoptions *opt;
1004 	struct tcp6_sock *newtcp6sk;
1005 	struct inet_sock *newinet;
1006 	struct tcp_sock *newtp;
1007 	struct sock *newsk;
1008 #ifdef CONFIG_TCP_MD5SIG
1009 	struct tcp_md5sig_key *key;
1010 #endif
1011 	struct flowi6 fl6;
1012 
1013 	if (skb->protocol == htons(ETH_P_IP)) {
1014 		/*
1015 		 *	v6 mapped
1016 		 */
1017 
1018 		newsk = tcp_v4_syn_recv_sock(sk, skb, req, dst,
1019 					     req_unhash, own_req);
1020 
1021 		if (!newsk)
1022 			return NULL;
1023 
1024 		newtcp6sk = (struct tcp6_sock *)newsk;
1025 		inet_sk(newsk)->pinet6 = &newtcp6sk->inet6;
1026 
1027 		newinet = inet_sk(newsk);
1028 		newnp = inet6_sk(newsk);
1029 		newtp = tcp_sk(newsk);
1030 
1031 		memcpy(newnp, np, sizeof(struct ipv6_pinfo));
1032 
1033 		newnp->saddr = newsk->sk_v6_rcv_saddr;
1034 
1035 		inet_csk(newsk)->icsk_af_ops = &ipv6_mapped;
1036 		newsk->sk_backlog_rcv = tcp_v4_do_rcv;
1037 #ifdef CONFIG_TCP_MD5SIG
1038 		newtp->af_specific = &tcp_sock_ipv6_mapped_specific;
1039 #endif
1040 
1041 		newnp->ipv6_ac_list = NULL;
1042 		newnp->ipv6_fl_list = NULL;
1043 		newnp->pktoptions  = NULL;
1044 		newnp->opt	   = NULL;
1045 		newnp->mcast_oif   = tcp_v6_iif(skb);
1046 		newnp->mcast_hops  = ipv6_hdr(skb)->hop_limit;
1047 		newnp->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(skb));
1048 		if (np->repflow)
1049 			newnp->flow_label = ip6_flowlabel(ipv6_hdr(skb));
1050 
1051 		/*
1052 		 * No need to charge this sock to the relevant IPv6 refcnt debug socks count
1053 		 * here, tcp_create_openreq_child now does this for us, see the comment in
1054 		 * that function for the gory details. -acme
1055 		 */
1056 
1057 		/* It is tricky place. Until this moment IPv4 tcp
1058 		   worked with IPv6 icsk.icsk_af_ops.
1059 		   Sync it now.
1060 		 */
1061 		tcp_sync_mss(newsk, inet_csk(newsk)->icsk_pmtu_cookie);
1062 
1063 		return newsk;
1064 	}
1065 
1066 	ireq = inet_rsk(req);
1067 
1068 	if (sk_acceptq_is_full(sk))
1069 		goto out_overflow;
1070 
1071 	if (!dst) {
1072 		dst = inet6_csk_route_req(sk, &fl6, req, IPPROTO_TCP);
1073 		if (!dst)
1074 			goto out;
1075 	}
1076 
1077 	newsk = tcp_create_openreq_child(sk, req, skb);
1078 	if (!newsk)
1079 		goto out_nonewsk;
1080 
1081 	/*
1082 	 * No need to charge this sock to the relevant IPv6 refcnt debug socks
1083 	 * count here, tcp_create_openreq_child now does this for us, see the
1084 	 * comment in that function for the gory details. -acme
1085 	 */
1086 
1087 	newsk->sk_gso_type = SKB_GSO_TCPV6;
1088 	ip6_dst_store(newsk, dst, NULL, NULL);
1089 	inet6_sk_rx_dst_set(newsk, skb);
1090 
1091 	newtcp6sk = (struct tcp6_sock *)newsk;
1092 	inet_sk(newsk)->pinet6 = &newtcp6sk->inet6;
1093 
1094 	newtp = tcp_sk(newsk);
1095 	newinet = inet_sk(newsk);
1096 	newnp = inet6_sk(newsk);
1097 
1098 	memcpy(newnp, np, sizeof(struct ipv6_pinfo));
1099 
1100 	newsk->sk_v6_daddr = ireq->ir_v6_rmt_addr;
1101 	newnp->saddr = ireq->ir_v6_loc_addr;
1102 	newsk->sk_v6_rcv_saddr = ireq->ir_v6_loc_addr;
1103 	newsk->sk_bound_dev_if = ireq->ir_iif;
1104 
1105 	/* Now IPv6 options...
1106 
1107 	   First: no IPv4 options.
1108 	 */
1109 	newinet->inet_opt = NULL;
1110 	newnp->ipv6_ac_list = NULL;
1111 	newnp->ipv6_fl_list = NULL;
1112 
1113 	/* Clone RX bits */
1114 	newnp->rxopt.all = np->rxopt.all;
1115 
1116 	newnp->pktoptions = NULL;
1117 	newnp->opt	  = NULL;
1118 	newnp->mcast_oif  = tcp_v6_iif(skb);
1119 	newnp->mcast_hops = ipv6_hdr(skb)->hop_limit;
1120 	newnp->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(skb));
1121 	if (np->repflow)
1122 		newnp->flow_label = ip6_flowlabel(ipv6_hdr(skb));
1123 
1124 	/* Clone native IPv6 options from listening socket (if any)
1125 
1126 	   Yes, keeping reference count would be much more clever,
1127 	   but we make one more one thing there: reattach optmem
1128 	   to newsk.
1129 	 */
1130 	opt = ireq->ipv6_opt;
1131 	if (!opt)
1132 		opt = rcu_dereference(np->opt);
1133 	if (opt) {
1134 		opt = ipv6_dup_options(newsk, opt);
1135 		RCU_INIT_POINTER(newnp->opt, opt);
1136 	}
1137 	inet_csk(newsk)->icsk_ext_hdr_len = 0;
1138 	if (opt)
1139 		inet_csk(newsk)->icsk_ext_hdr_len = opt->opt_nflen +
1140 						    opt->opt_flen;
1141 
1142 	tcp_ca_openreq_child(newsk, dst);
1143 
1144 	tcp_sync_mss(newsk, dst_mtu(dst));
1145 	newtp->advmss = dst_metric_advmss(dst);
1146 	if (tcp_sk(sk)->rx_opt.user_mss &&
1147 	    tcp_sk(sk)->rx_opt.user_mss < newtp->advmss)
1148 		newtp->advmss = tcp_sk(sk)->rx_opt.user_mss;
1149 
1150 	tcp_initialize_rcv_mss(newsk);
1151 
1152 	newinet->inet_daddr = newinet->inet_saddr = LOOPBACK4_IPV6;
1153 	newinet->inet_rcv_saddr = LOOPBACK4_IPV6;
1154 
1155 #ifdef CONFIG_TCP_MD5SIG
1156 	/* Copy over the MD5 key from the original socket */
1157 	key = tcp_v6_md5_do_lookup(sk, &newsk->sk_v6_daddr);
1158 	if (key) {
1159 		/* We're using one, so create a matching key
1160 		 * on the newsk structure. If we fail to get
1161 		 * memory, then we end up not copying the key
1162 		 * across. Shucks.
1163 		 */
1164 		tcp_md5_do_add(newsk, (union tcp_md5_addr *)&newsk->sk_v6_daddr,
1165 			       AF_INET6, key->key, key->keylen,
1166 			       sk_gfp_mask(sk, GFP_ATOMIC));
1167 	}
1168 #endif
1169 
1170 	if (__inet_inherit_port(sk, newsk) < 0) {
1171 		inet_csk_prepare_forced_close(newsk);
1172 		tcp_done(newsk);
1173 		goto out;
1174 	}
1175 	*own_req = inet_ehash_nolisten(newsk, req_to_sk(req_unhash));
1176 	if (*own_req) {
1177 		tcp_move_syn(newtp, req);
1178 
1179 		/* Clone pktoptions received with SYN, if we own the req */
1180 		if (ireq->pktopts) {
1181 			newnp->pktoptions = skb_clone(ireq->pktopts,
1182 						      sk_gfp_mask(sk, GFP_ATOMIC));
1183 			consume_skb(ireq->pktopts);
1184 			ireq->pktopts = NULL;
1185 			if (newnp->pktoptions)
1186 				skb_set_owner_r(newnp->pktoptions, newsk);
1187 		}
1188 	}
1189 
1190 	return newsk;
1191 
1192 out_overflow:
1193 	__NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
1194 out_nonewsk:
1195 	dst_release(dst);
1196 out:
1197 	tcp_listendrop(sk);
1198 	return NULL;
1199 }
1200 
1201 static void tcp_v6_restore_cb(struct sk_buff *skb)
1202 {
1203 	/* We need to move header back to the beginning if xfrm6_policy_check()
1204 	 * and tcp_v6_fill_cb() are going to be called again.
1205 	 * ip6_datagram_recv_specific_ctl() also expects IP6CB to be there.
1206 	 */
1207 	memmove(IP6CB(skb), &TCP_SKB_CB(skb)->header.h6,
1208 		sizeof(struct inet6_skb_parm));
1209 }
1210 
1211 /* The socket must have it's spinlock held when we get
1212  * here, unless it is a TCP_LISTEN socket.
1213  *
1214  * We have a potential double-lock case here, so even when
1215  * doing backlog processing we use the BH locking scheme.
1216  * This is because we cannot sleep with the original spinlock
1217  * held.
1218  */
1219 static int tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb)
1220 {
1221 	struct ipv6_pinfo *np = inet6_sk(sk);
1222 	struct tcp_sock *tp;
1223 	struct sk_buff *opt_skb = NULL;
1224 
1225 	/* Imagine: socket is IPv6. IPv4 packet arrives,
1226 	   goes to IPv4 receive handler and backlogged.
1227 	   From backlog it always goes here. Kerboom...
1228 	   Fortunately, tcp_rcv_established and rcv_established
1229 	   handle them correctly, but it is not case with
1230 	   tcp_v6_hnd_req and tcp_v6_send_reset().   --ANK
1231 	 */
1232 
1233 	if (skb->protocol == htons(ETH_P_IP))
1234 		return tcp_v4_do_rcv(sk, skb);
1235 
1236 	if (tcp_filter(sk, skb))
1237 		goto discard;
1238 
1239 	/*
1240 	 *	socket locking is here for SMP purposes as backlog rcv
1241 	 *	is currently called with bh processing disabled.
1242 	 */
1243 
1244 	/* Do Stevens' IPV6_PKTOPTIONS.
1245 
1246 	   Yes, guys, it is the only place in our code, where we
1247 	   may make it not affecting IPv4.
1248 	   The rest of code is protocol independent,
1249 	   and I do not like idea to uglify IPv4.
1250 
1251 	   Actually, all the idea behind IPV6_PKTOPTIONS
1252 	   looks not very well thought. For now we latch
1253 	   options, received in the last packet, enqueued
1254 	   by tcp. Feel free to propose better solution.
1255 					       --ANK (980728)
1256 	 */
1257 	if (np->rxopt.all)
1258 		opt_skb = skb_clone(skb, sk_gfp_mask(sk, GFP_ATOMIC));
1259 
1260 	if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
1261 		struct dst_entry *dst = sk->sk_rx_dst;
1262 
1263 		sock_rps_save_rxhash(sk, skb);
1264 		sk_mark_napi_id(sk, skb);
1265 		if (dst) {
1266 			if (inet_sk(sk)->rx_dst_ifindex != skb->skb_iif ||
1267 			    dst->ops->check(dst, np->rx_dst_cookie) == NULL) {
1268 				dst_release(dst);
1269 				sk->sk_rx_dst = NULL;
1270 			}
1271 		}
1272 
1273 		tcp_rcv_established(sk, skb, tcp_hdr(skb), skb->len);
1274 		if (opt_skb)
1275 			goto ipv6_pktoptions;
1276 		return 0;
1277 	}
1278 
1279 	if (tcp_checksum_complete(skb))
1280 		goto csum_err;
1281 
1282 	if (sk->sk_state == TCP_LISTEN) {
1283 		struct sock *nsk = tcp_v6_cookie_check(sk, skb);
1284 
1285 		if (!nsk)
1286 			goto discard;
1287 
1288 		if (nsk != sk) {
1289 			sock_rps_save_rxhash(nsk, skb);
1290 			sk_mark_napi_id(nsk, skb);
1291 			if (tcp_child_process(sk, nsk, skb))
1292 				goto reset;
1293 			if (opt_skb)
1294 				__kfree_skb(opt_skb);
1295 			return 0;
1296 		}
1297 	} else
1298 		sock_rps_save_rxhash(sk, skb);
1299 
1300 	if (tcp_rcv_state_process(sk, skb))
1301 		goto reset;
1302 	if (opt_skb)
1303 		goto ipv6_pktoptions;
1304 	return 0;
1305 
1306 reset:
1307 	tcp_v6_send_reset(sk, skb);
1308 discard:
1309 	if (opt_skb)
1310 		__kfree_skb(opt_skb);
1311 	kfree_skb(skb);
1312 	return 0;
1313 csum_err:
1314 	TCP_INC_STATS(sock_net(sk), TCP_MIB_CSUMERRORS);
1315 	TCP_INC_STATS(sock_net(sk), TCP_MIB_INERRS);
1316 	goto discard;
1317 
1318 
1319 ipv6_pktoptions:
1320 	/* Do you ask, what is it?
1321 
1322 	   1. skb was enqueued by tcp.
1323 	   2. skb is added to tail of read queue, rather than out of order.
1324 	   3. socket is not in passive state.
1325 	   4. Finally, it really contains options, which user wants to receive.
1326 	 */
1327 	tp = tcp_sk(sk);
1328 	if (TCP_SKB_CB(opt_skb)->end_seq == tp->rcv_nxt &&
1329 	    !((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN))) {
1330 		if (np->rxopt.bits.rxinfo || np->rxopt.bits.rxoinfo)
1331 			np->mcast_oif = tcp_v6_iif(opt_skb);
1332 		if (np->rxopt.bits.rxhlim || np->rxopt.bits.rxohlim)
1333 			np->mcast_hops = ipv6_hdr(opt_skb)->hop_limit;
1334 		if (np->rxopt.bits.rxflow || np->rxopt.bits.rxtclass)
1335 			np->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(opt_skb));
1336 		if (np->repflow)
1337 			np->flow_label = ip6_flowlabel(ipv6_hdr(opt_skb));
1338 		if (ipv6_opt_accepted(sk, opt_skb, &TCP_SKB_CB(opt_skb)->header.h6)) {
1339 			skb_set_owner_r(opt_skb, sk);
1340 			tcp_v6_restore_cb(opt_skb);
1341 			opt_skb = xchg(&np->pktoptions, opt_skb);
1342 		} else {
1343 			__kfree_skb(opt_skb);
1344 			opt_skb = xchg(&np->pktoptions, NULL);
1345 		}
1346 	}
1347 
1348 	kfree_skb(opt_skb);
1349 	return 0;
1350 }
1351 
1352 static void tcp_v6_fill_cb(struct sk_buff *skb, const struct ipv6hdr *hdr,
1353 			   const struct tcphdr *th)
1354 {
1355 	/* This is tricky: we move IP6CB at its correct location into
1356 	 * TCP_SKB_CB(). It must be done after xfrm6_policy_check(), because
1357 	 * _decode_session6() uses IP6CB().
1358 	 * barrier() makes sure compiler won't play aliasing games.
1359 	 */
1360 	memmove(&TCP_SKB_CB(skb)->header.h6, IP6CB(skb),
1361 		sizeof(struct inet6_skb_parm));
1362 	barrier();
1363 
1364 	TCP_SKB_CB(skb)->seq = ntohl(th->seq);
1365 	TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
1366 				    skb->len - th->doff*4);
1367 	TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
1368 	TCP_SKB_CB(skb)->tcp_flags = tcp_flag_byte(th);
1369 	TCP_SKB_CB(skb)->tcp_tw_isn = 0;
1370 	TCP_SKB_CB(skb)->ip_dsfield = ipv6_get_dsfield(hdr);
1371 	TCP_SKB_CB(skb)->sacked = 0;
1372 }
1373 
1374 static int tcp_v6_rcv(struct sk_buff *skb)
1375 {
1376 	const struct tcphdr *th;
1377 	const struct ipv6hdr *hdr;
1378 	bool refcounted;
1379 	struct sock *sk;
1380 	int ret;
1381 	struct net *net = dev_net(skb->dev);
1382 
1383 	if (skb->pkt_type != PACKET_HOST)
1384 		goto discard_it;
1385 
1386 	/*
1387 	 *	Count it even if it's bad.
1388 	 */
1389 	__TCP_INC_STATS(net, TCP_MIB_INSEGS);
1390 
1391 	if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
1392 		goto discard_it;
1393 
1394 	th = (const struct tcphdr *)skb->data;
1395 
1396 	if (unlikely(th->doff < sizeof(struct tcphdr)/4))
1397 		goto bad_packet;
1398 	if (!pskb_may_pull(skb, th->doff*4))
1399 		goto discard_it;
1400 
1401 	if (skb_checksum_init(skb, IPPROTO_TCP, ip6_compute_pseudo))
1402 		goto csum_error;
1403 
1404 	th = (const struct tcphdr *)skb->data;
1405 	hdr = ipv6_hdr(skb);
1406 
1407 lookup:
1408 	sk = __inet6_lookup_skb(&tcp_hashinfo, skb, __tcp_hdrlen(th),
1409 				th->source, th->dest, inet6_iif(skb),
1410 				&refcounted);
1411 	if (!sk)
1412 		goto no_tcp_socket;
1413 
1414 process:
1415 	if (sk->sk_state == TCP_TIME_WAIT)
1416 		goto do_time_wait;
1417 
1418 	if (sk->sk_state == TCP_NEW_SYN_RECV) {
1419 		struct request_sock *req = inet_reqsk(sk);
1420 		struct sock *nsk;
1421 
1422 		sk = req->rsk_listener;
1423 		tcp_v6_fill_cb(skb, hdr, th);
1424 		if (tcp_v6_inbound_md5_hash(sk, skb)) {
1425 			sk_drops_add(sk, skb);
1426 			reqsk_put(req);
1427 			goto discard_it;
1428 		}
1429 		if (unlikely(sk->sk_state != TCP_LISTEN)) {
1430 			inet_csk_reqsk_queue_drop_and_put(sk, req);
1431 			goto lookup;
1432 		}
1433 		sock_hold(sk);
1434 		refcounted = true;
1435 		nsk = tcp_check_req(sk, skb, req, false);
1436 		if (!nsk) {
1437 			reqsk_put(req);
1438 			goto discard_and_relse;
1439 		}
1440 		if (nsk == sk) {
1441 			reqsk_put(req);
1442 			tcp_v6_restore_cb(skb);
1443 		} else if (tcp_child_process(sk, nsk, skb)) {
1444 			tcp_v6_send_reset(nsk, skb);
1445 			goto discard_and_relse;
1446 		} else {
1447 			sock_put(sk);
1448 			return 0;
1449 		}
1450 	}
1451 	if (hdr->hop_limit < inet6_sk(sk)->min_hopcount) {
1452 		__NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP);
1453 		goto discard_and_relse;
1454 	}
1455 
1456 	if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb))
1457 		goto discard_and_relse;
1458 
1459 	tcp_v6_fill_cb(skb, hdr, th);
1460 
1461 	if (tcp_v6_inbound_md5_hash(sk, skb))
1462 		goto discard_and_relse;
1463 
1464 	if (tcp_filter(sk, skb))
1465 		goto discard_and_relse;
1466 	th = (const struct tcphdr *)skb->data;
1467 	hdr = ipv6_hdr(skb);
1468 
1469 	skb->dev = NULL;
1470 
1471 	if (sk->sk_state == TCP_LISTEN) {
1472 		ret = tcp_v6_do_rcv(sk, skb);
1473 		goto put_and_return;
1474 	}
1475 
1476 	sk_incoming_cpu_update(sk);
1477 
1478 	bh_lock_sock_nested(sk);
1479 	tcp_segs_in(tcp_sk(sk), skb);
1480 	ret = 0;
1481 	if (!sock_owned_by_user(sk)) {
1482 		if (!tcp_prequeue(sk, skb))
1483 			ret = tcp_v6_do_rcv(sk, skb);
1484 	} else if (tcp_add_backlog(sk, skb)) {
1485 		goto discard_and_relse;
1486 	}
1487 	bh_unlock_sock(sk);
1488 
1489 put_and_return:
1490 	if (refcounted)
1491 		sock_put(sk);
1492 	return ret ? -1 : 0;
1493 
1494 no_tcp_socket:
1495 	if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb))
1496 		goto discard_it;
1497 
1498 	tcp_v6_fill_cb(skb, hdr, th);
1499 
1500 	if (tcp_checksum_complete(skb)) {
1501 csum_error:
1502 		__TCP_INC_STATS(net, TCP_MIB_CSUMERRORS);
1503 bad_packet:
1504 		__TCP_INC_STATS(net, TCP_MIB_INERRS);
1505 	} else {
1506 		tcp_v6_send_reset(NULL, skb);
1507 	}
1508 
1509 discard_it:
1510 	kfree_skb(skb);
1511 	return 0;
1512 
1513 discard_and_relse:
1514 	sk_drops_add(sk, skb);
1515 	if (refcounted)
1516 		sock_put(sk);
1517 	goto discard_it;
1518 
1519 do_time_wait:
1520 	if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
1521 		inet_twsk_put(inet_twsk(sk));
1522 		goto discard_it;
1523 	}
1524 
1525 	tcp_v6_fill_cb(skb, hdr, th);
1526 
1527 	if (tcp_checksum_complete(skb)) {
1528 		inet_twsk_put(inet_twsk(sk));
1529 		goto csum_error;
1530 	}
1531 
1532 	switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) {
1533 	case TCP_TW_SYN:
1534 	{
1535 		struct sock *sk2;
1536 
1537 		sk2 = inet6_lookup_listener(dev_net(skb->dev), &tcp_hashinfo,
1538 					    skb, __tcp_hdrlen(th),
1539 					    &ipv6_hdr(skb)->saddr, th->source,
1540 					    &ipv6_hdr(skb)->daddr,
1541 					    ntohs(th->dest), tcp_v6_iif(skb));
1542 		if (sk2) {
1543 			struct inet_timewait_sock *tw = inet_twsk(sk);
1544 			inet_twsk_deschedule_put(tw);
1545 			sk = sk2;
1546 			tcp_v6_restore_cb(skb);
1547 			refcounted = false;
1548 			goto process;
1549 		}
1550 		/* Fall through to ACK */
1551 	}
1552 	case TCP_TW_ACK:
1553 		tcp_v6_timewait_ack(sk, skb);
1554 		break;
1555 	case TCP_TW_RST:
1556 		tcp_v6_restore_cb(skb);
1557 		tcp_v6_send_reset(sk, skb);
1558 		inet_twsk_deschedule_put(inet_twsk(sk));
1559 		goto discard_it;
1560 	case TCP_TW_SUCCESS:
1561 		;
1562 	}
1563 	goto discard_it;
1564 }
1565 
1566 static void tcp_v6_early_demux(struct sk_buff *skb)
1567 {
1568 	const struct ipv6hdr *hdr;
1569 	const struct tcphdr *th;
1570 	struct sock *sk;
1571 
1572 	if (skb->pkt_type != PACKET_HOST)
1573 		return;
1574 
1575 	if (!pskb_may_pull(skb, skb_transport_offset(skb) + sizeof(struct tcphdr)))
1576 		return;
1577 
1578 	hdr = ipv6_hdr(skb);
1579 	th = tcp_hdr(skb);
1580 
1581 	if (th->doff < sizeof(struct tcphdr) / 4)
1582 		return;
1583 
1584 	/* Note : We use inet6_iif() here, not tcp_v6_iif() */
1585 	sk = __inet6_lookup_established(dev_net(skb->dev), &tcp_hashinfo,
1586 					&hdr->saddr, th->source,
1587 					&hdr->daddr, ntohs(th->dest),
1588 					inet6_iif(skb));
1589 	if (sk) {
1590 		skb->sk = sk;
1591 		skb->destructor = sock_edemux;
1592 		if (sk_fullsock(sk)) {
1593 			struct dst_entry *dst = READ_ONCE(sk->sk_rx_dst);
1594 
1595 			if (dst)
1596 				dst = dst_check(dst, inet6_sk(sk)->rx_dst_cookie);
1597 			if (dst &&
1598 			    inet_sk(sk)->rx_dst_ifindex == skb->skb_iif)
1599 				skb_dst_set_noref(skb, dst);
1600 		}
1601 	}
1602 }
1603 
1604 static struct timewait_sock_ops tcp6_timewait_sock_ops = {
1605 	.twsk_obj_size	= sizeof(struct tcp6_timewait_sock),
1606 	.twsk_unique	= tcp_twsk_unique,
1607 	.twsk_destructor = tcp_twsk_destructor,
1608 };
1609 
1610 static const struct inet_connection_sock_af_ops ipv6_specific = {
1611 	.queue_xmit	   = inet6_csk_xmit,
1612 	.send_check	   = tcp_v6_send_check,
1613 	.rebuild_header	   = inet6_sk_rebuild_header,
1614 	.sk_rx_dst_set	   = inet6_sk_rx_dst_set,
1615 	.conn_request	   = tcp_v6_conn_request,
1616 	.syn_recv_sock	   = tcp_v6_syn_recv_sock,
1617 	.net_header_len	   = sizeof(struct ipv6hdr),
1618 	.net_frag_header_len = sizeof(struct frag_hdr),
1619 	.setsockopt	   = ipv6_setsockopt,
1620 	.getsockopt	   = ipv6_getsockopt,
1621 	.addr2sockaddr	   = inet6_csk_addr2sockaddr,
1622 	.sockaddr_len	   = sizeof(struct sockaddr_in6),
1623 	.bind_conflict	   = inet6_csk_bind_conflict,
1624 #ifdef CONFIG_COMPAT
1625 	.compat_setsockopt = compat_ipv6_setsockopt,
1626 	.compat_getsockopt = compat_ipv6_getsockopt,
1627 #endif
1628 	.mtu_reduced	   = tcp_v6_mtu_reduced,
1629 };
1630 
1631 #ifdef CONFIG_TCP_MD5SIG
1632 static const struct tcp_sock_af_ops tcp_sock_ipv6_specific = {
1633 	.md5_lookup	=	tcp_v6_md5_lookup,
1634 	.calc_md5_hash	=	tcp_v6_md5_hash_skb,
1635 	.md5_parse	=	tcp_v6_parse_md5_keys,
1636 };
1637 #endif
1638 
1639 /*
1640  *	TCP over IPv4 via INET6 API
1641  */
1642 static const struct inet_connection_sock_af_ops ipv6_mapped = {
1643 	.queue_xmit	   = ip_queue_xmit,
1644 	.send_check	   = tcp_v4_send_check,
1645 	.rebuild_header	   = inet_sk_rebuild_header,
1646 	.sk_rx_dst_set	   = inet_sk_rx_dst_set,
1647 	.conn_request	   = tcp_v6_conn_request,
1648 	.syn_recv_sock	   = tcp_v6_syn_recv_sock,
1649 	.net_header_len	   = sizeof(struct iphdr),
1650 	.setsockopt	   = ipv6_setsockopt,
1651 	.getsockopt	   = ipv6_getsockopt,
1652 	.addr2sockaddr	   = inet6_csk_addr2sockaddr,
1653 	.sockaddr_len	   = sizeof(struct sockaddr_in6),
1654 	.bind_conflict	   = inet6_csk_bind_conflict,
1655 #ifdef CONFIG_COMPAT
1656 	.compat_setsockopt = compat_ipv6_setsockopt,
1657 	.compat_getsockopt = compat_ipv6_getsockopt,
1658 #endif
1659 	.mtu_reduced	   = tcp_v4_mtu_reduced,
1660 };
1661 
1662 #ifdef CONFIG_TCP_MD5SIG
1663 static const struct tcp_sock_af_ops tcp_sock_ipv6_mapped_specific = {
1664 	.md5_lookup	=	tcp_v4_md5_lookup,
1665 	.calc_md5_hash	=	tcp_v4_md5_hash_skb,
1666 	.md5_parse	=	tcp_v6_parse_md5_keys,
1667 };
1668 #endif
1669 
1670 /* NOTE: A lot of things set to zero explicitly by call to
1671  *       sk_alloc() so need not be done here.
1672  */
1673 static int tcp_v6_init_sock(struct sock *sk)
1674 {
1675 	struct inet_connection_sock *icsk = inet_csk(sk);
1676 
1677 	tcp_init_sock(sk);
1678 
1679 	icsk->icsk_af_ops = &ipv6_specific;
1680 
1681 #ifdef CONFIG_TCP_MD5SIG
1682 	tcp_sk(sk)->af_specific = &tcp_sock_ipv6_specific;
1683 #endif
1684 
1685 	return 0;
1686 }
1687 
1688 static void tcp_v6_destroy_sock(struct sock *sk)
1689 {
1690 	tcp_v4_destroy_sock(sk);
1691 	inet6_destroy_sock(sk);
1692 }
1693 
1694 #ifdef CONFIG_PROC_FS
1695 /* Proc filesystem TCPv6 sock list dumping. */
1696 static void get_openreq6(struct seq_file *seq,
1697 			 const struct request_sock *req, int i)
1698 {
1699 	long ttd = req->rsk_timer.expires - jiffies;
1700 	const struct in6_addr *src = &inet_rsk(req)->ir_v6_loc_addr;
1701 	const struct in6_addr *dest = &inet_rsk(req)->ir_v6_rmt_addr;
1702 
1703 	if (ttd < 0)
1704 		ttd = 0;
1705 
1706 	seq_printf(seq,
1707 		   "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
1708 		   "%02X %08X:%08X %02X:%08lX %08X %5u %8d %d %d %pK\n",
1709 		   i,
1710 		   src->s6_addr32[0], src->s6_addr32[1],
1711 		   src->s6_addr32[2], src->s6_addr32[3],
1712 		   inet_rsk(req)->ir_num,
1713 		   dest->s6_addr32[0], dest->s6_addr32[1],
1714 		   dest->s6_addr32[2], dest->s6_addr32[3],
1715 		   ntohs(inet_rsk(req)->ir_rmt_port),
1716 		   TCP_SYN_RECV,
1717 		   0, 0, /* could print option size, but that is af dependent. */
1718 		   1,   /* timers active (only the expire timer) */
1719 		   jiffies_to_clock_t(ttd),
1720 		   req->num_timeout,
1721 		   from_kuid_munged(seq_user_ns(seq),
1722 				    sock_i_uid(req->rsk_listener)),
1723 		   0,  /* non standard timer */
1724 		   0, /* open_requests have no inode */
1725 		   0, req);
1726 }
1727 
1728 static void get_tcp6_sock(struct seq_file *seq, struct sock *sp, int i)
1729 {
1730 	const struct in6_addr *dest, *src;
1731 	__u16 destp, srcp;
1732 	int timer_active;
1733 	unsigned long timer_expires;
1734 	const struct inet_sock *inet = inet_sk(sp);
1735 	const struct tcp_sock *tp = tcp_sk(sp);
1736 	const struct inet_connection_sock *icsk = inet_csk(sp);
1737 	const struct fastopen_queue *fastopenq = &icsk->icsk_accept_queue.fastopenq;
1738 	int rx_queue;
1739 	int state;
1740 
1741 	dest  = &sp->sk_v6_daddr;
1742 	src   = &sp->sk_v6_rcv_saddr;
1743 	destp = ntohs(inet->inet_dport);
1744 	srcp  = ntohs(inet->inet_sport);
1745 
1746 	if (icsk->icsk_pending == ICSK_TIME_RETRANS ||
1747 	    icsk->icsk_pending == ICSK_TIME_EARLY_RETRANS ||
1748 	    icsk->icsk_pending == ICSK_TIME_LOSS_PROBE) {
1749 		timer_active	= 1;
1750 		timer_expires	= icsk->icsk_timeout;
1751 	} else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
1752 		timer_active	= 4;
1753 		timer_expires	= icsk->icsk_timeout;
1754 	} else if (timer_pending(&sp->sk_timer)) {
1755 		timer_active	= 2;
1756 		timer_expires	= sp->sk_timer.expires;
1757 	} else {
1758 		timer_active	= 0;
1759 		timer_expires = jiffies;
1760 	}
1761 
1762 	state = sk_state_load(sp);
1763 	if (state == TCP_LISTEN)
1764 		rx_queue = sp->sk_ack_backlog;
1765 	else
1766 		/* Because we don't lock the socket,
1767 		 * we might find a transient negative value.
1768 		 */
1769 		rx_queue = max_t(int, tp->rcv_nxt - tp->copied_seq, 0);
1770 
1771 	seq_printf(seq,
1772 		   "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
1773 		   "%02X %08X:%08X %02X:%08lX %08X %5u %8d %lu %d %pK %lu %lu %u %u %d\n",
1774 		   i,
1775 		   src->s6_addr32[0], src->s6_addr32[1],
1776 		   src->s6_addr32[2], src->s6_addr32[3], srcp,
1777 		   dest->s6_addr32[0], dest->s6_addr32[1],
1778 		   dest->s6_addr32[2], dest->s6_addr32[3], destp,
1779 		   state,
1780 		   tp->write_seq - tp->snd_una,
1781 		   rx_queue,
1782 		   timer_active,
1783 		   jiffies_delta_to_clock_t(timer_expires - jiffies),
1784 		   icsk->icsk_retransmits,
1785 		   from_kuid_munged(seq_user_ns(seq), sock_i_uid(sp)),
1786 		   icsk->icsk_probes_out,
1787 		   sock_i_ino(sp),
1788 		   atomic_read(&sp->sk_refcnt), sp,
1789 		   jiffies_to_clock_t(icsk->icsk_rto),
1790 		   jiffies_to_clock_t(icsk->icsk_ack.ato),
1791 		   (icsk->icsk_ack.quick << 1) | icsk->icsk_ack.pingpong,
1792 		   tp->snd_cwnd,
1793 		   state == TCP_LISTEN ?
1794 			fastopenq->max_qlen :
1795 			(tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh)
1796 		   );
1797 }
1798 
1799 static void get_timewait6_sock(struct seq_file *seq,
1800 			       struct inet_timewait_sock *tw, int i)
1801 {
1802 	long delta = tw->tw_timer.expires - jiffies;
1803 	const struct in6_addr *dest, *src;
1804 	__u16 destp, srcp;
1805 
1806 	dest = &tw->tw_v6_daddr;
1807 	src  = &tw->tw_v6_rcv_saddr;
1808 	destp = ntohs(tw->tw_dport);
1809 	srcp  = ntohs(tw->tw_sport);
1810 
1811 	seq_printf(seq,
1812 		   "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
1813 		   "%02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK\n",
1814 		   i,
1815 		   src->s6_addr32[0], src->s6_addr32[1],
1816 		   src->s6_addr32[2], src->s6_addr32[3], srcp,
1817 		   dest->s6_addr32[0], dest->s6_addr32[1],
1818 		   dest->s6_addr32[2], dest->s6_addr32[3], destp,
1819 		   tw->tw_substate, 0, 0,
1820 		   3, jiffies_delta_to_clock_t(delta), 0, 0, 0, 0,
1821 		   atomic_read(&tw->tw_refcnt), tw);
1822 }
1823 
1824 static int tcp6_seq_show(struct seq_file *seq, void *v)
1825 {
1826 	struct tcp_iter_state *st;
1827 	struct sock *sk = v;
1828 
1829 	if (v == SEQ_START_TOKEN) {
1830 		seq_puts(seq,
1831 			 "  sl  "
1832 			 "local_address                         "
1833 			 "remote_address                        "
1834 			 "st tx_queue rx_queue tr tm->when retrnsmt"
1835 			 "   uid  timeout inode\n");
1836 		goto out;
1837 	}
1838 	st = seq->private;
1839 
1840 	if (sk->sk_state == TCP_TIME_WAIT)
1841 		get_timewait6_sock(seq, v, st->num);
1842 	else if (sk->sk_state == TCP_NEW_SYN_RECV)
1843 		get_openreq6(seq, v, st->num);
1844 	else
1845 		get_tcp6_sock(seq, v, st->num);
1846 out:
1847 	return 0;
1848 }
1849 
1850 static const struct file_operations tcp6_afinfo_seq_fops = {
1851 	.owner   = THIS_MODULE,
1852 	.open    = tcp_seq_open,
1853 	.read    = seq_read,
1854 	.llseek  = seq_lseek,
1855 	.release = seq_release_net
1856 };
1857 
1858 static struct tcp_seq_afinfo tcp6_seq_afinfo = {
1859 	.name		= "tcp6",
1860 	.family		= AF_INET6,
1861 	.seq_fops	= &tcp6_afinfo_seq_fops,
1862 	.seq_ops	= {
1863 		.show		= tcp6_seq_show,
1864 	},
1865 };
1866 
1867 int __net_init tcp6_proc_init(struct net *net)
1868 {
1869 	return tcp_proc_register(net, &tcp6_seq_afinfo);
1870 }
1871 
1872 void tcp6_proc_exit(struct net *net)
1873 {
1874 	tcp_proc_unregister(net, &tcp6_seq_afinfo);
1875 }
1876 #endif
1877 
1878 struct proto tcpv6_prot = {
1879 	.name			= "TCPv6",
1880 	.owner			= THIS_MODULE,
1881 	.close			= tcp_close,
1882 	.connect		= tcp_v6_connect,
1883 	.disconnect		= tcp_disconnect,
1884 	.accept			= inet_csk_accept,
1885 	.ioctl			= tcp_ioctl,
1886 	.init			= tcp_v6_init_sock,
1887 	.destroy		= tcp_v6_destroy_sock,
1888 	.shutdown		= tcp_shutdown,
1889 	.setsockopt		= tcp_setsockopt,
1890 	.getsockopt		= tcp_getsockopt,
1891 	.recvmsg		= tcp_recvmsg,
1892 	.sendmsg		= tcp_sendmsg,
1893 	.sendpage		= tcp_sendpage,
1894 	.backlog_rcv		= tcp_v6_do_rcv,
1895 	.release_cb		= tcp_release_cb,
1896 	.hash			= inet6_hash,
1897 	.unhash			= inet_unhash,
1898 	.get_port		= inet_csk_get_port,
1899 	.enter_memory_pressure	= tcp_enter_memory_pressure,
1900 	.stream_memory_free	= tcp_stream_memory_free,
1901 	.sockets_allocated	= &tcp_sockets_allocated,
1902 	.memory_allocated	= &tcp_memory_allocated,
1903 	.memory_pressure	= &tcp_memory_pressure,
1904 	.orphan_count		= &tcp_orphan_count,
1905 	.sysctl_mem		= sysctl_tcp_mem,
1906 	.sysctl_wmem		= sysctl_tcp_wmem,
1907 	.sysctl_rmem		= sysctl_tcp_rmem,
1908 	.max_header		= MAX_TCP_HEADER,
1909 	.obj_size		= sizeof(struct tcp6_sock),
1910 	.slab_flags		= SLAB_DESTROY_BY_RCU,
1911 	.twsk_prot		= &tcp6_timewait_sock_ops,
1912 	.rsk_prot		= &tcp6_request_sock_ops,
1913 	.h.hashinfo		= &tcp_hashinfo,
1914 	.no_autobind		= true,
1915 #ifdef CONFIG_COMPAT
1916 	.compat_setsockopt	= compat_tcp_setsockopt,
1917 	.compat_getsockopt	= compat_tcp_getsockopt,
1918 #endif
1919 	.diag_destroy		= tcp_abort,
1920 };
1921 
1922 static const struct inet6_protocol tcpv6_protocol = {
1923 	.early_demux	=	tcp_v6_early_demux,
1924 	.handler	=	tcp_v6_rcv,
1925 	.err_handler	=	tcp_v6_err,
1926 	.flags		=	INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
1927 };
1928 
1929 static struct inet_protosw tcpv6_protosw = {
1930 	.type		=	SOCK_STREAM,
1931 	.protocol	=	IPPROTO_TCP,
1932 	.prot		=	&tcpv6_prot,
1933 	.ops		=	&inet6_stream_ops,
1934 	.flags		=	INET_PROTOSW_PERMANENT |
1935 				INET_PROTOSW_ICSK,
1936 };
1937 
1938 static int __net_init tcpv6_net_init(struct net *net)
1939 {
1940 	return inet_ctl_sock_create(&net->ipv6.tcp_sk, PF_INET6,
1941 				    SOCK_RAW, IPPROTO_TCP, net);
1942 }
1943 
1944 static void __net_exit tcpv6_net_exit(struct net *net)
1945 {
1946 	inet_ctl_sock_destroy(net->ipv6.tcp_sk);
1947 }
1948 
1949 static void __net_exit tcpv6_net_exit_batch(struct list_head *net_exit_list)
1950 {
1951 	inet_twsk_purge(&tcp_hashinfo, &tcp_death_row, AF_INET6);
1952 }
1953 
1954 static struct pernet_operations tcpv6_net_ops = {
1955 	.init	    = tcpv6_net_init,
1956 	.exit	    = tcpv6_net_exit,
1957 	.exit_batch = tcpv6_net_exit_batch,
1958 };
1959 
1960 int __init tcpv6_init(void)
1961 {
1962 	int ret;
1963 
1964 	ret = inet6_add_protocol(&tcpv6_protocol, IPPROTO_TCP);
1965 	if (ret)
1966 		goto out;
1967 
1968 	/* register inet6 protocol */
1969 	ret = inet6_register_protosw(&tcpv6_protosw);
1970 	if (ret)
1971 		goto out_tcpv6_protocol;
1972 
1973 	ret = register_pernet_subsys(&tcpv6_net_ops);
1974 	if (ret)
1975 		goto out_tcpv6_protosw;
1976 out:
1977 	return ret;
1978 
1979 out_tcpv6_protosw:
1980 	inet6_unregister_protosw(&tcpv6_protosw);
1981 out_tcpv6_protocol:
1982 	inet6_del_protocol(&tcpv6_protocol, IPPROTO_TCP);
1983 	goto out;
1984 }
1985 
1986 void tcpv6_exit(void)
1987 {
1988 	unregister_pernet_subsys(&tcpv6_net_ops);
1989 	inet6_unregister_protosw(&tcpv6_protosw);
1990 	inet6_del_protocol(&tcpv6_protocol, IPPROTO_TCP);
1991 }
1992