xref: /openbmc/linux/net/ipv6/tcp_ipv6.c (revision 4ed91d48259d9ddd378424d008f2e6559f7e78f8)
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 	u32 seq;
126 	int err;
127 	struct inet_timewait_death_row *tcp_death_row = &sock_net(sk)->ipv4.tcp_death_row;
128 
129 	if (addr_len < SIN6_LEN_RFC2133)
130 		return -EINVAL;
131 
132 	if (usin->sin6_family != AF_INET6)
133 		return -EAFNOSUPPORT;
134 
135 	memset(&fl6, 0, sizeof(fl6));
136 
137 	if (np->sndflow) {
138 		fl6.flowlabel = usin->sin6_flowinfo&IPV6_FLOWINFO_MASK;
139 		IP6_ECN_flow_init(fl6.flowlabel);
140 		if (fl6.flowlabel&IPV6_FLOWLABEL_MASK) {
141 			struct ip6_flowlabel *flowlabel;
142 			flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
143 			if (!flowlabel)
144 				return -EINVAL;
145 			fl6_sock_release(flowlabel);
146 		}
147 	}
148 
149 	/*
150 	 *	connect() to INADDR_ANY means loopback (BSD'ism).
151 	 */
152 
153 	if (ipv6_addr_any(&usin->sin6_addr)) {
154 		if (ipv6_addr_v4mapped(&sk->sk_v6_rcv_saddr))
155 			ipv6_addr_set_v4mapped(htonl(INADDR_LOOPBACK),
156 					       &usin->sin6_addr);
157 		else
158 			usin->sin6_addr = in6addr_loopback;
159 	}
160 
161 	addr_type = ipv6_addr_type(&usin->sin6_addr);
162 
163 	if (addr_type & IPV6_ADDR_MULTICAST)
164 		return -ENETUNREACH;
165 
166 	if (addr_type&IPV6_ADDR_LINKLOCAL) {
167 		if (addr_len >= sizeof(struct sockaddr_in6) &&
168 		    usin->sin6_scope_id) {
169 			/* If interface is set while binding, indices
170 			 * must coincide.
171 			 */
172 			if (sk->sk_bound_dev_if &&
173 			    sk->sk_bound_dev_if != usin->sin6_scope_id)
174 				return -EINVAL;
175 
176 			sk->sk_bound_dev_if = usin->sin6_scope_id;
177 		}
178 
179 		/* Connect to link-local address requires an interface */
180 		if (!sk->sk_bound_dev_if)
181 			return -EINVAL;
182 	}
183 
184 	if (tp->rx_opt.ts_recent_stamp &&
185 	    !ipv6_addr_equal(&sk->sk_v6_daddr, &usin->sin6_addr)) {
186 		tp->rx_opt.ts_recent = 0;
187 		tp->rx_opt.ts_recent_stamp = 0;
188 		tp->write_seq = 0;
189 	}
190 
191 	sk->sk_v6_daddr = usin->sin6_addr;
192 	np->flow_label = fl6.flowlabel;
193 
194 	/*
195 	 *	TCP over IPv4
196 	 */
197 
198 	if (addr_type & IPV6_ADDR_MAPPED) {
199 		u32 exthdrlen = icsk->icsk_ext_hdr_len;
200 		struct sockaddr_in sin;
201 
202 		SOCK_DEBUG(sk, "connect: ipv4 mapped\n");
203 
204 		if (__ipv6_only_sock(sk))
205 			return -ENETUNREACH;
206 
207 		sin.sin_family = AF_INET;
208 		sin.sin_port = usin->sin6_port;
209 		sin.sin_addr.s_addr = usin->sin6_addr.s6_addr32[3];
210 
211 		icsk->icsk_af_ops = &ipv6_mapped;
212 		sk->sk_backlog_rcv = tcp_v4_do_rcv;
213 #ifdef CONFIG_TCP_MD5SIG
214 		tp->af_specific = &tcp_sock_ipv6_mapped_specific;
215 #endif
216 
217 		err = tcp_v4_connect(sk, (struct sockaddr *)&sin, sizeof(sin));
218 
219 		if (err) {
220 			icsk->icsk_ext_hdr_len = exthdrlen;
221 			icsk->icsk_af_ops = &ipv6_specific;
222 			sk->sk_backlog_rcv = tcp_v6_do_rcv;
223 #ifdef CONFIG_TCP_MD5SIG
224 			tp->af_specific = &tcp_sock_ipv6_specific;
225 #endif
226 			goto failure;
227 		}
228 		np->saddr = sk->sk_v6_rcv_saddr;
229 
230 		return err;
231 	}
232 
233 	if (!ipv6_addr_any(&sk->sk_v6_rcv_saddr))
234 		saddr = &sk->sk_v6_rcv_saddr;
235 
236 	fl6.flowi6_proto = IPPROTO_TCP;
237 	fl6.daddr = sk->sk_v6_daddr;
238 	fl6.saddr = saddr ? *saddr : np->saddr;
239 	fl6.flowi6_oif = sk->sk_bound_dev_if;
240 	fl6.flowi6_mark = sk->sk_mark;
241 	fl6.fl6_dport = usin->sin6_port;
242 	fl6.fl6_sport = inet->inet_sport;
243 	fl6.flowi6_uid = sk->sk_uid;
244 
245 	opt = rcu_dereference_protected(np->opt, lockdep_sock_is_held(sk));
246 	final_p = fl6_update_dst(&fl6, opt, &final);
247 
248 	security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));
249 
250 	dst = ip6_dst_lookup_flow(sk, &fl6, final_p);
251 	if (IS_ERR(dst)) {
252 		err = PTR_ERR(dst);
253 		goto failure;
254 	}
255 
256 	if (!saddr) {
257 		saddr = &fl6.saddr;
258 		sk->sk_v6_rcv_saddr = *saddr;
259 	}
260 
261 	/* set the source address */
262 	np->saddr = *saddr;
263 	inet->inet_rcv_saddr = LOOPBACK4_IPV6;
264 
265 	sk->sk_gso_type = SKB_GSO_TCPV6;
266 	ip6_dst_store(sk, dst, NULL, NULL);
267 
268 	if (tcp_death_row->sysctl_tw_recycle &&
269 	    !tp->rx_opt.ts_recent_stamp &&
270 	    ipv6_addr_equal(&fl6.daddr, &sk->sk_v6_daddr))
271 		tcp_fetch_timewait_stamp(sk, dst);
272 
273 	icsk->icsk_ext_hdr_len = 0;
274 	if (opt)
275 		icsk->icsk_ext_hdr_len = opt->opt_flen +
276 					 opt->opt_nflen;
277 
278 	tp->rx_opt.mss_clamp = IPV6_MIN_MTU - sizeof(struct tcphdr) - sizeof(struct ipv6hdr);
279 
280 	inet->inet_dport = usin->sin6_port;
281 
282 	tcp_set_state(sk, TCP_SYN_SENT);
283 	err = inet6_hash_connect(tcp_death_row, sk);
284 	if (err)
285 		goto late_failure;
286 
287 	sk_set_txhash(sk);
288 
289 	if (likely(!tp->repair)) {
290 		seq = secure_tcpv6_sequence_number(np->saddr.s6_addr32,
291 						   sk->sk_v6_daddr.s6_addr32,
292 						   inet->inet_sport,
293 						   inet->inet_dport,
294 						   &tp->tsoffset);
295 		if (!tp->write_seq)
296 			tp->write_seq = seq;
297 	}
298 
299 	if (tcp_fastopen_defer_connect(sk, &err))
300 		return err;
301 	if (err)
302 		goto late_failure;
303 
304 	err = tcp_connect(sk);
305 	if (err)
306 		goto late_failure;
307 
308 	return 0;
309 
310 late_failure:
311 	tcp_set_state(sk, TCP_CLOSE);
312 failure:
313 	inet->inet_dport = 0;
314 	sk->sk_route_caps = 0;
315 	return err;
316 }
317 
318 static void tcp_v6_mtu_reduced(struct sock *sk)
319 {
320 	struct dst_entry *dst;
321 
322 	if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE))
323 		return;
324 
325 	dst = inet6_csk_update_pmtu(sk, tcp_sk(sk)->mtu_info);
326 	if (!dst)
327 		return;
328 
329 	if (inet_csk(sk)->icsk_pmtu_cookie > dst_mtu(dst)) {
330 		tcp_sync_mss(sk, dst_mtu(dst));
331 		tcp_simple_retransmit(sk);
332 	}
333 }
334 
335 static void tcp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
336 		u8 type, u8 code, int offset, __be32 info)
337 {
338 	const struct ipv6hdr *hdr = (const struct ipv6hdr *)skb->data;
339 	const struct tcphdr *th = (struct tcphdr *)(skb->data+offset);
340 	struct net *net = dev_net(skb->dev);
341 	struct request_sock *fastopen;
342 	struct ipv6_pinfo *np;
343 	struct tcp_sock *tp;
344 	__u32 seq, snd_una;
345 	struct sock *sk;
346 	bool fatal;
347 	int err;
348 
349 	sk = __inet6_lookup_established(net, &tcp_hashinfo,
350 					&hdr->daddr, th->dest,
351 					&hdr->saddr, ntohs(th->source),
352 					skb->dev->ifindex);
353 
354 	if (!sk) {
355 		__ICMP6_INC_STATS(net, __in6_dev_get(skb->dev),
356 				  ICMP6_MIB_INERRORS);
357 		return;
358 	}
359 
360 	if (sk->sk_state == TCP_TIME_WAIT) {
361 		inet_twsk_put(inet_twsk(sk));
362 		return;
363 	}
364 	seq = ntohl(th->seq);
365 	fatal = icmpv6_err_convert(type, code, &err);
366 	if (sk->sk_state == TCP_NEW_SYN_RECV)
367 		return tcp_req_err(sk, seq, fatal);
368 
369 	bh_lock_sock(sk);
370 	if (sock_owned_by_user(sk) && type != ICMPV6_PKT_TOOBIG)
371 		__NET_INC_STATS(net, LINUX_MIB_LOCKDROPPEDICMPS);
372 
373 	if (sk->sk_state == TCP_CLOSE)
374 		goto out;
375 
376 	if (ipv6_hdr(skb)->hop_limit < inet6_sk(sk)->min_hopcount) {
377 		__NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP);
378 		goto out;
379 	}
380 
381 	tp = tcp_sk(sk);
382 	/* XXX (TFO) - tp->snd_una should be ISN (tcp_create_openreq_child() */
383 	fastopen = tp->fastopen_rsk;
384 	snd_una = fastopen ? tcp_rsk(fastopen)->snt_isn : tp->snd_una;
385 	if (sk->sk_state != TCP_LISTEN &&
386 	    !between(seq, snd_una, tp->snd_nxt)) {
387 		__NET_INC_STATS(net, LINUX_MIB_OUTOFWINDOWICMPS);
388 		goto out;
389 	}
390 
391 	np = inet6_sk(sk);
392 
393 	if (type == NDISC_REDIRECT) {
394 		struct dst_entry *dst = __sk_dst_check(sk, np->dst_cookie);
395 
396 		if (dst)
397 			dst->ops->redirect(dst, sk, skb);
398 		goto out;
399 	}
400 
401 	if (type == ICMPV6_PKT_TOOBIG) {
402 		/* We are not interested in TCP_LISTEN and open_requests
403 		 * (SYN-ACKs send out by Linux are always <576bytes so
404 		 * they should go through unfragmented).
405 		 */
406 		if (sk->sk_state == TCP_LISTEN)
407 			goto out;
408 
409 		if (!ip6_sk_accept_pmtu(sk))
410 			goto out;
411 
412 		tp->mtu_info = ntohl(info);
413 		if (!sock_owned_by_user(sk))
414 			tcp_v6_mtu_reduced(sk);
415 		else if (!test_and_set_bit(TCP_MTU_REDUCED_DEFERRED,
416 					   &sk->sk_tsq_flags))
417 			sock_hold(sk);
418 		goto out;
419 	}
420 
421 
422 	/* Might be for an request_sock */
423 	switch (sk->sk_state) {
424 	case TCP_SYN_SENT:
425 	case TCP_SYN_RECV:
426 		/* Only in fast or simultaneous open. If a fast open socket is
427 		 * is already accepted it is treated as a connected one below.
428 		 */
429 		if (fastopen && !fastopen->sk)
430 			break;
431 
432 		if (!sock_owned_by_user(sk)) {
433 			sk->sk_err = err;
434 			sk->sk_error_report(sk);		/* Wake people up to see the error (see connect in sock.c) */
435 
436 			tcp_done(sk);
437 		} else
438 			sk->sk_err_soft = err;
439 		goto out;
440 	}
441 
442 	if (!sock_owned_by_user(sk) && np->recverr) {
443 		sk->sk_err = err;
444 		sk->sk_error_report(sk);
445 	} else
446 		sk->sk_err_soft = err;
447 
448 out:
449 	bh_unlock_sock(sk);
450 	sock_put(sk);
451 }
452 
453 
454 static int tcp_v6_send_synack(const struct sock *sk, struct dst_entry *dst,
455 			      struct flowi *fl,
456 			      struct request_sock *req,
457 			      struct tcp_fastopen_cookie *foc,
458 			      enum tcp_synack_type synack_type)
459 {
460 	struct inet_request_sock *ireq = inet_rsk(req);
461 	struct ipv6_pinfo *np = inet6_sk(sk);
462 	struct ipv6_txoptions *opt;
463 	struct flowi6 *fl6 = &fl->u.ip6;
464 	struct sk_buff *skb;
465 	int err = -ENOMEM;
466 
467 	/* First, grab a route. */
468 	if (!dst && (dst = inet6_csk_route_req(sk, fl6, req,
469 					       IPPROTO_TCP)) == NULL)
470 		goto done;
471 
472 	skb = tcp_make_synack(sk, dst, req, foc, synack_type);
473 
474 	if (skb) {
475 		__tcp_v6_send_check(skb, &ireq->ir_v6_loc_addr,
476 				    &ireq->ir_v6_rmt_addr);
477 
478 		fl6->daddr = ireq->ir_v6_rmt_addr;
479 		if (np->repflow && ireq->pktopts)
480 			fl6->flowlabel = ip6_flowlabel(ipv6_hdr(ireq->pktopts));
481 
482 		rcu_read_lock();
483 		opt = ireq->ipv6_opt;
484 		if (!opt)
485 			opt = rcu_dereference(np->opt);
486 		err = ip6_xmit(sk, skb, fl6, sk->sk_mark, opt, np->tclass);
487 		rcu_read_unlock();
488 		err = net_xmit_eval(err);
489 	}
490 
491 done:
492 	return err;
493 }
494 
495 
496 static void tcp_v6_reqsk_destructor(struct request_sock *req)
497 {
498 	kfree(inet_rsk(req)->ipv6_opt);
499 	kfree_skb(inet_rsk(req)->pktopts);
500 }
501 
502 #ifdef CONFIG_TCP_MD5SIG
503 static struct tcp_md5sig_key *tcp_v6_md5_do_lookup(const struct sock *sk,
504 						   const struct in6_addr *addr)
505 {
506 	return tcp_md5_do_lookup(sk, (union tcp_md5_addr *)addr, AF_INET6);
507 }
508 
509 static struct tcp_md5sig_key *tcp_v6_md5_lookup(const struct sock *sk,
510 						const struct sock *addr_sk)
511 {
512 	return tcp_v6_md5_do_lookup(sk, &addr_sk->sk_v6_daddr);
513 }
514 
515 static int tcp_v6_parse_md5_keys(struct sock *sk, char __user *optval,
516 				 int optlen)
517 {
518 	struct tcp_md5sig cmd;
519 	struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)&cmd.tcpm_addr;
520 
521 	if (optlen < sizeof(cmd))
522 		return -EINVAL;
523 
524 	if (copy_from_user(&cmd, optval, sizeof(cmd)))
525 		return -EFAULT;
526 
527 	if (sin6->sin6_family != AF_INET6)
528 		return -EINVAL;
529 
530 	if (!cmd.tcpm_keylen) {
531 		if (ipv6_addr_v4mapped(&sin6->sin6_addr))
532 			return tcp_md5_do_del(sk, (union tcp_md5_addr *)&sin6->sin6_addr.s6_addr32[3],
533 					      AF_INET);
534 		return tcp_md5_do_del(sk, (union tcp_md5_addr *)&sin6->sin6_addr,
535 				      AF_INET6);
536 	}
537 
538 	if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN)
539 		return -EINVAL;
540 
541 	if (ipv6_addr_v4mapped(&sin6->sin6_addr))
542 		return tcp_md5_do_add(sk, (union tcp_md5_addr *)&sin6->sin6_addr.s6_addr32[3],
543 				      AF_INET, cmd.tcpm_key, cmd.tcpm_keylen, GFP_KERNEL);
544 
545 	return tcp_md5_do_add(sk, (union tcp_md5_addr *)&sin6->sin6_addr,
546 			      AF_INET6, cmd.tcpm_key, cmd.tcpm_keylen, GFP_KERNEL);
547 }
548 
549 static int tcp_v6_md5_hash_headers(struct tcp_md5sig_pool *hp,
550 				   const struct in6_addr *daddr,
551 				   const struct in6_addr *saddr,
552 				   const struct tcphdr *th, int nbytes)
553 {
554 	struct tcp6_pseudohdr *bp;
555 	struct scatterlist sg;
556 	struct tcphdr *_th;
557 
558 	bp = hp->scratch;
559 	/* 1. TCP pseudo-header (RFC2460) */
560 	bp->saddr = *saddr;
561 	bp->daddr = *daddr;
562 	bp->protocol = cpu_to_be32(IPPROTO_TCP);
563 	bp->len = cpu_to_be32(nbytes);
564 
565 	_th = (struct tcphdr *)(bp + 1);
566 	memcpy(_th, th, sizeof(*th));
567 	_th->check = 0;
568 
569 	sg_init_one(&sg, bp, sizeof(*bp) + sizeof(*th));
570 	ahash_request_set_crypt(hp->md5_req, &sg, NULL,
571 				sizeof(*bp) + sizeof(*th));
572 	return crypto_ahash_update(hp->md5_req);
573 }
574 
575 static int tcp_v6_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key,
576 			       const struct in6_addr *daddr, struct in6_addr *saddr,
577 			       const struct tcphdr *th)
578 {
579 	struct tcp_md5sig_pool *hp;
580 	struct ahash_request *req;
581 
582 	hp = tcp_get_md5sig_pool();
583 	if (!hp)
584 		goto clear_hash_noput;
585 	req = hp->md5_req;
586 
587 	if (crypto_ahash_init(req))
588 		goto clear_hash;
589 	if (tcp_v6_md5_hash_headers(hp, daddr, saddr, th, th->doff << 2))
590 		goto clear_hash;
591 	if (tcp_md5_hash_key(hp, key))
592 		goto clear_hash;
593 	ahash_request_set_crypt(req, NULL, md5_hash, 0);
594 	if (crypto_ahash_final(req))
595 		goto clear_hash;
596 
597 	tcp_put_md5sig_pool();
598 	return 0;
599 
600 clear_hash:
601 	tcp_put_md5sig_pool();
602 clear_hash_noput:
603 	memset(md5_hash, 0, 16);
604 	return 1;
605 }
606 
607 static int tcp_v6_md5_hash_skb(char *md5_hash,
608 			       const struct tcp_md5sig_key *key,
609 			       const struct sock *sk,
610 			       const struct sk_buff *skb)
611 {
612 	const struct in6_addr *saddr, *daddr;
613 	struct tcp_md5sig_pool *hp;
614 	struct ahash_request *req;
615 	const struct tcphdr *th = tcp_hdr(skb);
616 
617 	if (sk) { /* valid for establish/request sockets */
618 		saddr = &sk->sk_v6_rcv_saddr;
619 		daddr = &sk->sk_v6_daddr;
620 	} else {
621 		const struct ipv6hdr *ip6h = ipv6_hdr(skb);
622 		saddr = &ip6h->saddr;
623 		daddr = &ip6h->daddr;
624 	}
625 
626 	hp = tcp_get_md5sig_pool();
627 	if (!hp)
628 		goto clear_hash_noput;
629 	req = hp->md5_req;
630 
631 	if (crypto_ahash_init(req))
632 		goto clear_hash;
633 
634 	if (tcp_v6_md5_hash_headers(hp, daddr, saddr, th, skb->len))
635 		goto clear_hash;
636 	if (tcp_md5_hash_skb_data(hp, skb, th->doff << 2))
637 		goto clear_hash;
638 	if (tcp_md5_hash_key(hp, key))
639 		goto clear_hash;
640 	ahash_request_set_crypt(req, NULL, md5_hash, 0);
641 	if (crypto_ahash_final(req))
642 		goto clear_hash;
643 
644 	tcp_put_md5sig_pool();
645 	return 0;
646 
647 clear_hash:
648 	tcp_put_md5sig_pool();
649 clear_hash_noput:
650 	memset(md5_hash, 0, 16);
651 	return 1;
652 }
653 
654 #endif
655 
656 static bool tcp_v6_inbound_md5_hash(const struct sock *sk,
657 				    const struct sk_buff *skb)
658 {
659 #ifdef CONFIG_TCP_MD5SIG
660 	const __u8 *hash_location = NULL;
661 	struct tcp_md5sig_key *hash_expected;
662 	const struct ipv6hdr *ip6h = ipv6_hdr(skb);
663 	const struct tcphdr *th = tcp_hdr(skb);
664 	int genhash;
665 	u8 newhash[16];
666 
667 	hash_expected = tcp_v6_md5_do_lookup(sk, &ip6h->saddr);
668 	hash_location = tcp_parse_md5sig_option(th);
669 
670 	/* We've parsed the options - do we have a hash? */
671 	if (!hash_expected && !hash_location)
672 		return false;
673 
674 	if (hash_expected && !hash_location) {
675 		NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5NOTFOUND);
676 		return true;
677 	}
678 
679 	if (!hash_expected && hash_location) {
680 		NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5UNEXPECTED);
681 		return true;
682 	}
683 
684 	/* check the signature */
685 	genhash = tcp_v6_md5_hash_skb(newhash,
686 				      hash_expected,
687 				      NULL, skb);
688 
689 	if (genhash || memcmp(hash_location, newhash, 16) != 0) {
690 		NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5FAILURE);
691 		net_info_ratelimited("MD5 Hash %s for [%pI6c]:%u->[%pI6c]:%u\n",
692 				     genhash ? "failed" : "mismatch",
693 				     &ip6h->saddr, ntohs(th->source),
694 				     &ip6h->daddr, ntohs(th->dest));
695 		return true;
696 	}
697 #endif
698 	return false;
699 }
700 
701 static void tcp_v6_init_req(struct request_sock *req,
702 			    const struct sock *sk_listener,
703 			    struct sk_buff *skb)
704 {
705 	struct inet_request_sock *ireq = inet_rsk(req);
706 	const struct ipv6_pinfo *np = inet6_sk(sk_listener);
707 
708 	ireq->ir_v6_rmt_addr = ipv6_hdr(skb)->saddr;
709 	ireq->ir_v6_loc_addr = ipv6_hdr(skb)->daddr;
710 
711 	/* So that link locals have meaning */
712 	if (!sk_listener->sk_bound_dev_if &&
713 	    ipv6_addr_type(&ireq->ir_v6_rmt_addr) & IPV6_ADDR_LINKLOCAL)
714 		ireq->ir_iif = tcp_v6_iif(skb);
715 
716 	if (!TCP_SKB_CB(skb)->tcp_tw_isn &&
717 	    (ipv6_opt_accepted(sk_listener, skb, &TCP_SKB_CB(skb)->header.h6) ||
718 	     np->rxopt.bits.rxinfo ||
719 	     np->rxopt.bits.rxoinfo || np->rxopt.bits.rxhlim ||
720 	     np->rxopt.bits.rxohlim || np->repflow)) {
721 		atomic_inc(&skb->users);
722 		ireq->pktopts = skb;
723 	}
724 }
725 
726 static struct dst_entry *tcp_v6_route_req(const struct sock *sk,
727 					  struct flowi *fl,
728 					  const struct request_sock *req,
729 					  bool *strict)
730 {
731 	if (strict)
732 		*strict = true;
733 	return inet6_csk_route_req(sk, &fl->u.ip6, req, IPPROTO_TCP);
734 }
735 
736 struct request_sock_ops tcp6_request_sock_ops __read_mostly = {
737 	.family		=	AF_INET6,
738 	.obj_size	=	sizeof(struct tcp6_request_sock),
739 	.rtx_syn_ack	=	tcp_rtx_synack,
740 	.send_ack	=	tcp_v6_reqsk_send_ack,
741 	.destructor	=	tcp_v6_reqsk_destructor,
742 	.send_reset	=	tcp_v6_send_reset,
743 	.syn_ack_timeout =	tcp_syn_ack_timeout,
744 };
745 
746 static const struct tcp_request_sock_ops tcp_request_sock_ipv6_ops = {
747 	.mss_clamp	=	IPV6_MIN_MTU - sizeof(struct tcphdr) -
748 				sizeof(struct ipv6hdr),
749 #ifdef CONFIG_TCP_MD5SIG
750 	.req_md5_lookup	=	tcp_v6_md5_lookup,
751 	.calc_md5_hash	=	tcp_v6_md5_hash_skb,
752 #endif
753 	.init_req	=	tcp_v6_init_req,
754 #ifdef CONFIG_SYN_COOKIES
755 	.cookie_init_seq =	cookie_v6_init_sequence,
756 #endif
757 	.route_req	=	tcp_v6_route_req,
758 	.init_seq	=	tcp_v6_init_sequence,
759 	.send_synack	=	tcp_v6_send_synack,
760 };
761 
762 static void tcp_v6_send_response(const struct sock *sk, struct sk_buff *skb, u32 seq,
763 				 u32 ack, u32 win, u32 tsval, u32 tsecr,
764 				 int oif, struct tcp_md5sig_key *key, int rst,
765 				 u8 tclass, __be32 label)
766 {
767 	const struct tcphdr *th = tcp_hdr(skb);
768 	struct tcphdr *t1;
769 	struct sk_buff *buff;
770 	struct flowi6 fl6;
771 	struct net *net = sk ? sock_net(sk) : dev_net(skb_dst(skb)->dev);
772 	struct sock *ctl_sk = net->ipv6.tcp_sk;
773 	unsigned int tot_len = sizeof(struct tcphdr);
774 	struct dst_entry *dst;
775 	__be32 *topt;
776 
777 	if (tsecr)
778 		tot_len += TCPOLEN_TSTAMP_ALIGNED;
779 #ifdef CONFIG_TCP_MD5SIG
780 	if (key)
781 		tot_len += TCPOLEN_MD5SIG_ALIGNED;
782 #endif
783 
784 	buff = alloc_skb(MAX_HEADER + sizeof(struct ipv6hdr) + tot_len,
785 			 GFP_ATOMIC);
786 	if (!buff)
787 		return;
788 
789 	skb_reserve(buff, MAX_HEADER + sizeof(struct ipv6hdr) + tot_len);
790 
791 	t1 = (struct tcphdr *) skb_push(buff, tot_len);
792 	skb_reset_transport_header(buff);
793 
794 	/* Swap the send and the receive. */
795 	memset(t1, 0, sizeof(*t1));
796 	t1->dest = th->source;
797 	t1->source = th->dest;
798 	t1->doff = tot_len / 4;
799 	t1->seq = htonl(seq);
800 	t1->ack_seq = htonl(ack);
801 	t1->ack = !rst || !th->ack;
802 	t1->rst = rst;
803 	t1->window = htons(win);
804 
805 	topt = (__be32 *)(t1 + 1);
806 
807 	if (tsecr) {
808 		*topt++ = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
809 				(TCPOPT_TIMESTAMP << 8) | TCPOLEN_TIMESTAMP);
810 		*topt++ = htonl(tsval);
811 		*topt++ = htonl(tsecr);
812 	}
813 
814 #ifdef CONFIG_TCP_MD5SIG
815 	if (key) {
816 		*topt++ = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
817 				(TCPOPT_MD5SIG << 8) | TCPOLEN_MD5SIG);
818 		tcp_v6_md5_hash_hdr((__u8 *)topt, key,
819 				    &ipv6_hdr(skb)->saddr,
820 				    &ipv6_hdr(skb)->daddr, t1);
821 	}
822 #endif
823 
824 	memset(&fl6, 0, sizeof(fl6));
825 	fl6.daddr = ipv6_hdr(skb)->saddr;
826 	fl6.saddr = ipv6_hdr(skb)->daddr;
827 	fl6.flowlabel = label;
828 
829 	buff->ip_summed = CHECKSUM_PARTIAL;
830 	buff->csum = 0;
831 
832 	__tcp_v6_send_check(buff, &fl6.saddr, &fl6.daddr);
833 
834 	fl6.flowi6_proto = IPPROTO_TCP;
835 	if (rt6_need_strict(&fl6.daddr) && !oif)
836 		fl6.flowi6_oif = tcp_v6_iif(skb);
837 	else {
838 		if (!oif && netif_index_is_l3_master(net, skb->skb_iif))
839 			oif = skb->skb_iif;
840 
841 		fl6.flowi6_oif = oif;
842 	}
843 
844 	fl6.flowi6_mark = IP6_REPLY_MARK(net, skb->mark);
845 	fl6.fl6_dport = t1->dest;
846 	fl6.fl6_sport = t1->source;
847 	fl6.flowi6_uid = sock_net_uid(net, sk && sk_fullsock(sk) ? sk : NULL);
848 	security_skb_classify_flow(skb, flowi6_to_flowi(&fl6));
849 
850 	/* Pass a socket to ip6_dst_lookup either it is for RST
851 	 * Underlying function will use this to retrieve the network
852 	 * namespace
853 	 */
854 	dst = ip6_dst_lookup_flow(ctl_sk, &fl6, NULL);
855 	if (!IS_ERR(dst)) {
856 		skb_dst_set(buff, dst);
857 		ip6_xmit(ctl_sk, buff, &fl6, fl6.flowi6_mark, NULL, tclass);
858 		TCP_INC_STATS(net, TCP_MIB_OUTSEGS);
859 		if (rst)
860 			TCP_INC_STATS(net, TCP_MIB_OUTRSTS);
861 		return;
862 	}
863 
864 	kfree_skb(buff);
865 }
866 
867 static void tcp_v6_send_reset(const struct sock *sk, struct sk_buff *skb)
868 {
869 	const struct tcphdr *th = tcp_hdr(skb);
870 	u32 seq = 0, ack_seq = 0;
871 	struct tcp_md5sig_key *key = NULL;
872 #ifdef CONFIG_TCP_MD5SIG
873 	const __u8 *hash_location = NULL;
874 	struct ipv6hdr *ipv6h = ipv6_hdr(skb);
875 	unsigned char newhash[16];
876 	int genhash;
877 	struct sock *sk1 = NULL;
878 #endif
879 	int oif;
880 
881 	if (th->rst)
882 		return;
883 
884 	/* If sk not NULL, it means we did a successful lookup and incoming
885 	 * route had to be correct. prequeue might have dropped our dst.
886 	 */
887 	if (!sk && !ipv6_unicast_destination(skb))
888 		return;
889 
890 #ifdef CONFIG_TCP_MD5SIG
891 	rcu_read_lock();
892 	hash_location = tcp_parse_md5sig_option(th);
893 	if (sk && sk_fullsock(sk)) {
894 		key = tcp_v6_md5_do_lookup(sk, &ipv6h->saddr);
895 	} else if (hash_location) {
896 		/*
897 		 * active side is lost. Try to find listening socket through
898 		 * source port, and then find md5 key through listening socket.
899 		 * we are not loose security here:
900 		 * Incoming packet is checked with md5 hash with finding key,
901 		 * no RST generated if md5 hash doesn't match.
902 		 */
903 		sk1 = inet6_lookup_listener(dev_net(skb_dst(skb)->dev),
904 					   &tcp_hashinfo, NULL, 0,
905 					   &ipv6h->saddr,
906 					   th->source, &ipv6h->daddr,
907 					   ntohs(th->source), tcp_v6_iif(skb));
908 		if (!sk1)
909 			goto out;
910 
911 		key = tcp_v6_md5_do_lookup(sk1, &ipv6h->saddr);
912 		if (!key)
913 			goto out;
914 
915 		genhash = tcp_v6_md5_hash_skb(newhash, key, NULL, skb);
916 		if (genhash || memcmp(hash_location, newhash, 16) != 0)
917 			goto out;
918 	}
919 #endif
920 
921 	if (th->ack)
922 		seq = ntohl(th->ack_seq);
923 	else
924 		ack_seq = ntohl(th->seq) + th->syn + th->fin + skb->len -
925 			  (th->doff << 2);
926 
927 	oif = sk ? sk->sk_bound_dev_if : 0;
928 	tcp_v6_send_response(sk, skb, seq, ack_seq, 0, 0, 0, oif, key, 1, 0, 0);
929 
930 #ifdef CONFIG_TCP_MD5SIG
931 out:
932 	rcu_read_unlock();
933 #endif
934 }
935 
936 static void tcp_v6_send_ack(const struct sock *sk, struct sk_buff *skb, u32 seq,
937 			    u32 ack, u32 win, u32 tsval, u32 tsecr, int oif,
938 			    struct tcp_md5sig_key *key, u8 tclass,
939 			    __be32 label)
940 {
941 	tcp_v6_send_response(sk, skb, seq, ack, win, tsval, tsecr, oif, key, 0,
942 			     tclass, label);
943 }
944 
945 static void tcp_v6_timewait_ack(struct sock *sk, struct sk_buff *skb)
946 {
947 	struct inet_timewait_sock *tw = inet_twsk(sk);
948 	struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
949 
950 	tcp_v6_send_ack(sk, skb, tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
951 			tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
952 			tcp_time_stamp + tcptw->tw_ts_offset,
953 			tcptw->tw_ts_recent, tw->tw_bound_dev_if, tcp_twsk_md5_key(tcptw),
954 			tw->tw_tclass, cpu_to_be32(tw->tw_flowlabel));
955 
956 	inet_twsk_put(tw);
957 }
958 
959 static void tcp_v6_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb,
960 				  struct request_sock *req)
961 {
962 	/* sk->sk_state == TCP_LISTEN -> for regular TCP_SYN_RECV
963 	 * sk->sk_state == TCP_SYN_RECV -> for Fast Open.
964 	 */
965 	/* RFC 7323 2.3
966 	 * The window field (SEG.WND) of every outgoing segment, with the
967 	 * exception of <SYN> segments, MUST be right-shifted by
968 	 * Rcv.Wind.Shift bits:
969 	 */
970 	tcp_v6_send_ack(sk, skb, (sk->sk_state == TCP_LISTEN) ?
971 			tcp_rsk(req)->snt_isn + 1 : tcp_sk(sk)->snd_nxt,
972 			tcp_rsk(req)->rcv_nxt,
973 			req->rsk_rcv_wnd >> inet_rsk(req)->rcv_wscale,
974 			tcp_time_stamp + tcp_rsk(req)->ts_off,
975 			req->ts_recent, sk->sk_bound_dev_if,
976 			tcp_v6_md5_do_lookup(sk, &ipv6_hdr(skb)->daddr),
977 			0, 0);
978 }
979 
980 
981 static struct sock *tcp_v6_cookie_check(struct sock *sk, struct sk_buff *skb)
982 {
983 #ifdef CONFIG_SYN_COOKIES
984 	const struct tcphdr *th = tcp_hdr(skb);
985 
986 	if (!th->syn)
987 		sk = cookie_v6_check(sk, skb);
988 #endif
989 	return sk;
990 }
991 
992 static int tcp_v6_conn_request(struct sock *sk, struct sk_buff *skb)
993 {
994 	if (skb->protocol == htons(ETH_P_IP))
995 		return tcp_v4_conn_request(sk, skb);
996 
997 	if (!ipv6_unicast_destination(skb))
998 		goto drop;
999 
1000 	return tcp_conn_request(&tcp6_request_sock_ops,
1001 				&tcp_request_sock_ipv6_ops, sk, skb);
1002 
1003 drop:
1004 	tcp_listendrop(sk);
1005 	return 0; /* don't send reset */
1006 }
1007 
1008 static void tcp_v6_restore_cb(struct sk_buff *skb)
1009 {
1010 	/* We need to move header back to the beginning if xfrm6_policy_check()
1011 	 * and tcp_v6_fill_cb() are going to be called again.
1012 	 * ip6_datagram_recv_specific_ctl() also expects IP6CB to be there.
1013 	 */
1014 	memmove(IP6CB(skb), &TCP_SKB_CB(skb)->header.h6,
1015 		sizeof(struct inet6_skb_parm));
1016 }
1017 
1018 static struct sock *tcp_v6_syn_recv_sock(const struct sock *sk, struct sk_buff *skb,
1019 					 struct request_sock *req,
1020 					 struct dst_entry *dst,
1021 					 struct request_sock *req_unhash,
1022 					 bool *own_req)
1023 {
1024 	struct inet_request_sock *ireq;
1025 	struct ipv6_pinfo *newnp;
1026 	const struct ipv6_pinfo *np = inet6_sk(sk);
1027 	struct ipv6_txoptions *opt;
1028 	struct tcp6_sock *newtcp6sk;
1029 	struct inet_sock *newinet;
1030 	struct tcp_sock *newtp;
1031 	struct sock *newsk;
1032 #ifdef CONFIG_TCP_MD5SIG
1033 	struct tcp_md5sig_key *key;
1034 #endif
1035 	struct flowi6 fl6;
1036 
1037 	if (skb->protocol == htons(ETH_P_IP)) {
1038 		/*
1039 		 *	v6 mapped
1040 		 */
1041 
1042 		newsk = tcp_v4_syn_recv_sock(sk, skb, req, dst,
1043 					     req_unhash, own_req);
1044 
1045 		if (!newsk)
1046 			return NULL;
1047 
1048 		newtcp6sk = (struct tcp6_sock *)newsk;
1049 		inet_sk(newsk)->pinet6 = &newtcp6sk->inet6;
1050 
1051 		newinet = inet_sk(newsk);
1052 		newnp = inet6_sk(newsk);
1053 		newtp = tcp_sk(newsk);
1054 
1055 		memcpy(newnp, np, sizeof(struct ipv6_pinfo));
1056 
1057 		newnp->saddr = newsk->sk_v6_rcv_saddr;
1058 
1059 		inet_csk(newsk)->icsk_af_ops = &ipv6_mapped;
1060 		newsk->sk_backlog_rcv = tcp_v4_do_rcv;
1061 #ifdef CONFIG_TCP_MD5SIG
1062 		newtp->af_specific = &tcp_sock_ipv6_mapped_specific;
1063 #endif
1064 
1065 		newnp->ipv6_ac_list = NULL;
1066 		newnp->ipv6_fl_list = NULL;
1067 		newnp->pktoptions  = NULL;
1068 		newnp->opt	   = NULL;
1069 		newnp->mcast_oif   = tcp_v6_iif(skb);
1070 		newnp->mcast_hops  = ipv6_hdr(skb)->hop_limit;
1071 		newnp->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(skb));
1072 		if (np->repflow)
1073 			newnp->flow_label = ip6_flowlabel(ipv6_hdr(skb));
1074 
1075 		/*
1076 		 * No need to charge this sock to the relevant IPv6 refcnt debug socks count
1077 		 * here, tcp_create_openreq_child now does this for us, see the comment in
1078 		 * that function for the gory details. -acme
1079 		 */
1080 
1081 		/* It is tricky place. Until this moment IPv4 tcp
1082 		   worked with IPv6 icsk.icsk_af_ops.
1083 		   Sync it now.
1084 		 */
1085 		tcp_sync_mss(newsk, inet_csk(newsk)->icsk_pmtu_cookie);
1086 
1087 		return newsk;
1088 	}
1089 
1090 	ireq = inet_rsk(req);
1091 
1092 	if (sk_acceptq_is_full(sk))
1093 		goto out_overflow;
1094 
1095 	if (!dst) {
1096 		dst = inet6_csk_route_req(sk, &fl6, req, IPPROTO_TCP);
1097 		if (!dst)
1098 			goto out;
1099 	}
1100 
1101 	newsk = tcp_create_openreq_child(sk, req, skb);
1102 	if (!newsk)
1103 		goto out_nonewsk;
1104 
1105 	/*
1106 	 * No need to charge this sock to the relevant IPv6 refcnt debug socks
1107 	 * count here, tcp_create_openreq_child now does this for us, see the
1108 	 * comment in that function for the gory details. -acme
1109 	 */
1110 
1111 	newsk->sk_gso_type = SKB_GSO_TCPV6;
1112 	ip6_dst_store(newsk, dst, NULL, NULL);
1113 	inet6_sk_rx_dst_set(newsk, skb);
1114 
1115 	newtcp6sk = (struct tcp6_sock *)newsk;
1116 	inet_sk(newsk)->pinet6 = &newtcp6sk->inet6;
1117 
1118 	newtp = tcp_sk(newsk);
1119 	newinet = inet_sk(newsk);
1120 	newnp = inet6_sk(newsk);
1121 
1122 	memcpy(newnp, np, sizeof(struct ipv6_pinfo));
1123 
1124 	newsk->sk_v6_daddr = ireq->ir_v6_rmt_addr;
1125 	newnp->saddr = ireq->ir_v6_loc_addr;
1126 	newsk->sk_v6_rcv_saddr = ireq->ir_v6_loc_addr;
1127 	newsk->sk_bound_dev_if = ireq->ir_iif;
1128 
1129 	/* Now IPv6 options...
1130 
1131 	   First: no IPv4 options.
1132 	 */
1133 	newinet->inet_opt = NULL;
1134 	newnp->ipv6_ac_list = NULL;
1135 	newnp->ipv6_fl_list = NULL;
1136 
1137 	/* Clone RX bits */
1138 	newnp->rxopt.all = np->rxopt.all;
1139 
1140 	newnp->pktoptions = NULL;
1141 	newnp->opt	  = NULL;
1142 	newnp->mcast_oif  = tcp_v6_iif(skb);
1143 	newnp->mcast_hops = ipv6_hdr(skb)->hop_limit;
1144 	newnp->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(skb));
1145 	if (np->repflow)
1146 		newnp->flow_label = ip6_flowlabel(ipv6_hdr(skb));
1147 
1148 	/* Clone native IPv6 options from listening socket (if any)
1149 
1150 	   Yes, keeping reference count would be much more clever,
1151 	   but we make one more one thing there: reattach optmem
1152 	   to newsk.
1153 	 */
1154 	opt = ireq->ipv6_opt;
1155 	if (!opt)
1156 		opt = rcu_dereference(np->opt);
1157 	if (opt) {
1158 		opt = ipv6_dup_options(newsk, opt);
1159 		RCU_INIT_POINTER(newnp->opt, opt);
1160 	}
1161 	inet_csk(newsk)->icsk_ext_hdr_len = 0;
1162 	if (opt)
1163 		inet_csk(newsk)->icsk_ext_hdr_len = opt->opt_nflen +
1164 						    opt->opt_flen;
1165 
1166 	tcp_ca_openreq_child(newsk, dst);
1167 
1168 	tcp_sync_mss(newsk, dst_mtu(dst));
1169 	newtp->advmss = tcp_mss_clamp(tcp_sk(sk), dst_metric_advmss(dst));
1170 
1171 	tcp_initialize_rcv_mss(newsk);
1172 
1173 	newinet->inet_daddr = newinet->inet_saddr = LOOPBACK4_IPV6;
1174 	newinet->inet_rcv_saddr = LOOPBACK4_IPV6;
1175 
1176 #ifdef CONFIG_TCP_MD5SIG
1177 	/* Copy over the MD5 key from the original socket */
1178 	key = tcp_v6_md5_do_lookup(sk, &newsk->sk_v6_daddr);
1179 	if (key) {
1180 		/* We're using one, so create a matching key
1181 		 * on the newsk structure. If we fail to get
1182 		 * memory, then we end up not copying the key
1183 		 * across. Shucks.
1184 		 */
1185 		tcp_md5_do_add(newsk, (union tcp_md5_addr *)&newsk->sk_v6_daddr,
1186 			       AF_INET6, key->key, key->keylen,
1187 			       sk_gfp_mask(sk, GFP_ATOMIC));
1188 	}
1189 #endif
1190 
1191 	if (__inet_inherit_port(sk, newsk) < 0) {
1192 		inet_csk_prepare_forced_close(newsk);
1193 		tcp_done(newsk);
1194 		goto out;
1195 	}
1196 	*own_req = inet_ehash_nolisten(newsk, req_to_sk(req_unhash));
1197 	if (*own_req) {
1198 		tcp_move_syn(newtp, req);
1199 
1200 		/* Clone pktoptions received with SYN, if we own the req */
1201 		if (ireq->pktopts) {
1202 			newnp->pktoptions = skb_clone(ireq->pktopts,
1203 						      sk_gfp_mask(sk, GFP_ATOMIC));
1204 			consume_skb(ireq->pktopts);
1205 			ireq->pktopts = NULL;
1206 			if (newnp->pktoptions) {
1207 				tcp_v6_restore_cb(newnp->pktoptions);
1208 				skb_set_owner_r(newnp->pktoptions, newsk);
1209 			}
1210 		}
1211 	}
1212 
1213 	return newsk;
1214 
1215 out_overflow:
1216 	__NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
1217 out_nonewsk:
1218 	dst_release(dst);
1219 out:
1220 	tcp_listendrop(sk);
1221 	return NULL;
1222 }
1223 
1224 /* The socket must have it's spinlock held when we get
1225  * here, unless it is a TCP_LISTEN socket.
1226  *
1227  * We have a potential double-lock case here, so even when
1228  * doing backlog processing we use the BH locking scheme.
1229  * This is because we cannot sleep with the original spinlock
1230  * held.
1231  */
1232 static int tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb)
1233 {
1234 	struct ipv6_pinfo *np = inet6_sk(sk);
1235 	struct tcp_sock *tp;
1236 	struct sk_buff *opt_skb = NULL;
1237 
1238 	/* Imagine: socket is IPv6. IPv4 packet arrives,
1239 	   goes to IPv4 receive handler and backlogged.
1240 	   From backlog it always goes here. Kerboom...
1241 	   Fortunately, tcp_rcv_established and rcv_established
1242 	   handle them correctly, but it is not case with
1243 	   tcp_v6_hnd_req and tcp_v6_send_reset().   --ANK
1244 	 */
1245 
1246 	if (skb->protocol == htons(ETH_P_IP))
1247 		return tcp_v4_do_rcv(sk, skb);
1248 
1249 	if (tcp_filter(sk, skb))
1250 		goto discard;
1251 
1252 	/*
1253 	 *	socket locking is here for SMP purposes as backlog rcv
1254 	 *	is currently called with bh processing disabled.
1255 	 */
1256 
1257 	/* Do Stevens' IPV6_PKTOPTIONS.
1258 
1259 	   Yes, guys, it is the only place in our code, where we
1260 	   may make it not affecting IPv4.
1261 	   The rest of code is protocol independent,
1262 	   and I do not like idea to uglify IPv4.
1263 
1264 	   Actually, all the idea behind IPV6_PKTOPTIONS
1265 	   looks not very well thought. For now we latch
1266 	   options, received in the last packet, enqueued
1267 	   by tcp. Feel free to propose better solution.
1268 					       --ANK (980728)
1269 	 */
1270 	if (np->rxopt.all)
1271 		opt_skb = skb_clone(skb, sk_gfp_mask(sk, GFP_ATOMIC));
1272 
1273 	if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
1274 		struct dst_entry *dst = sk->sk_rx_dst;
1275 
1276 		sock_rps_save_rxhash(sk, skb);
1277 		sk_mark_napi_id(sk, skb);
1278 		if (dst) {
1279 			if (inet_sk(sk)->rx_dst_ifindex != skb->skb_iif ||
1280 			    dst->ops->check(dst, np->rx_dst_cookie) == NULL) {
1281 				dst_release(dst);
1282 				sk->sk_rx_dst = NULL;
1283 			}
1284 		}
1285 
1286 		tcp_rcv_established(sk, skb, tcp_hdr(skb), skb->len);
1287 		if (opt_skb)
1288 			goto ipv6_pktoptions;
1289 		return 0;
1290 	}
1291 
1292 	if (tcp_checksum_complete(skb))
1293 		goto csum_err;
1294 
1295 	if (sk->sk_state == TCP_LISTEN) {
1296 		struct sock *nsk = tcp_v6_cookie_check(sk, skb);
1297 
1298 		if (!nsk)
1299 			goto discard;
1300 
1301 		if (nsk != sk) {
1302 			sock_rps_save_rxhash(nsk, skb);
1303 			sk_mark_napi_id(nsk, skb);
1304 			if (tcp_child_process(sk, nsk, skb))
1305 				goto reset;
1306 			if (opt_skb)
1307 				__kfree_skb(opt_skb);
1308 			return 0;
1309 		}
1310 	} else
1311 		sock_rps_save_rxhash(sk, skb);
1312 
1313 	if (tcp_rcv_state_process(sk, skb))
1314 		goto reset;
1315 	if (opt_skb)
1316 		goto ipv6_pktoptions;
1317 	return 0;
1318 
1319 reset:
1320 	tcp_v6_send_reset(sk, skb);
1321 discard:
1322 	if (opt_skb)
1323 		__kfree_skb(opt_skb);
1324 	kfree_skb(skb);
1325 	return 0;
1326 csum_err:
1327 	TCP_INC_STATS(sock_net(sk), TCP_MIB_CSUMERRORS);
1328 	TCP_INC_STATS(sock_net(sk), TCP_MIB_INERRS);
1329 	goto discard;
1330 
1331 
1332 ipv6_pktoptions:
1333 	/* Do you ask, what is it?
1334 
1335 	   1. skb was enqueued by tcp.
1336 	   2. skb is added to tail of read queue, rather than out of order.
1337 	   3. socket is not in passive state.
1338 	   4. Finally, it really contains options, which user wants to receive.
1339 	 */
1340 	tp = tcp_sk(sk);
1341 	if (TCP_SKB_CB(opt_skb)->end_seq == tp->rcv_nxt &&
1342 	    !((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN))) {
1343 		if (np->rxopt.bits.rxinfo || np->rxopt.bits.rxoinfo)
1344 			np->mcast_oif = tcp_v6_iif(opt_skb);
1345 		if (np->rxopt.bits.rxhlim || np->rxopt.bits.rxohlim)
1346 			np->mcast_hops = ipv6_hdr(opt_skb)->hop_limit;
1347 		if (np->rxopt.bits.rxflow || np->rxopt.bits.rxtclass)
1348 			np->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(opt_skb));
1349 		if (np->repflow)
1350 			np->flow_label = ip6_flowlabel(ipv6_hdr(opt_skb));
1351 		if (ipv6_opt_accepted(sk, opt_skb, &TCP_SKB_CB(opt_skb)->header.h6)) {
1352 			skb_set_owner_r(opt_skb, sk);
1353 			tcp_v6_restore_cb(opt_skb);
1354 			opt_skb = xchg(&np->pktoptions, opt_skb);
1355 		} else {
1356 			__kfree_skb(opt_skb);
1357 			opt_skb = xchg(&np->pktoptions, NULL);
1358 		}
1359 	}
1360 
1361 	kfree_skb(opt_skb);
1362 	return 0;
1363 }
1364 
1365 static void tcp_v6_fill_cb(struct sk_buff *skb, const struct ipv6hdr *hdr,
1366 			   const struct tcphdr *th)
1367 {
1368 	/* This is tricky: we move IP6CB at its correct location into
1369 	 * TCP_SKB_CB(). It must be done after xfrm6_policy_check(), because
1370 	 * _decode_session6() uses IP6CB().
1371 	 * barrier() makes sure compiler won't play aliasing games.
1372 	 */
1373 	memmove(&TCP_SKB_CB(skb)->header.h6, IP6CB(skb),
1374 		sizeof(struct inet6_skb_parm));
1375 	barrier();
1376 
1377 	TCP_SKB_CB(skb)->seq = ntohl(th->seq);
1378 	TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
1379 				    skb->len - th->doff*4);
1380 	TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
1381 	TCP_SKB_CB(skb)->tcp_flags = tcp_flag_byte(th);
1382 	TCP_SKB_CB(skb)->tcp_tw_isn = 0;
1383 	TCP_SKB_CB(skb)->ip_dsfield = ipv6_get_dsfield(hdr);
1384 	TCP_SKB_CB(skb)->sacked = 0;
1385 }
1386 
1387 static int tcp_v6_rcv(struct sk_buff *skb)
1388 {
1389 	const struct tcphdr *th;
1390 	const struct ipv6hdr *hdr;
1391 	bool refcounted;
1392 	struct sock *sk;
1393 	int ret;
1394 	struct net *net = dev_net(skb->dev);
1395 
1396 	if (skb->pkt_type != PACKET_HOST)
1397 		goto discard_it;
1398 
1399 	/*
1400 	 *	Count it even if it's bad.
1401 	 */
1402 	__TCP_INC_STATS(net, TCP_MIB_INSEGS);
1403 
1404 	if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
1405 		goto discard_it;
1406 
1407 	th = (const struct tcphdr *)skb->data;
1408 
1409 	if (unlikely(th->doff < sizeof(struct tcphdr)/4))
1410 		goto bad_packet;
1411 	if (!pskb_may_pull(skb, th->doff*4))
1412 		goto discard_it;
1413 
1414 	if (skb_checksum_init(skb, IPPROTO_TCP, ip6_compute_pseudo))
1415 		goto csum_error;
1416 
1417 	th = (const struct tcphdr *)skb->data;
1418 	hdr = ipv6_hdr(skb);
1419 
1420 lookup:
1421 	sk = __inet6_lookup_skb(&tcp_hashinfo, skb, __tcp_hdrlen(th),
1422 				th->source, th->dest, inet6_iif(skb),
1423 				&refcounted);
1424 	if (!sk)
1425 		goto no_tcp_socket;
1426 
1427 process:
1428 	if (sk->sk_state == TCP_TIME_WAIT)
1429 		goto do_time_wait;
1430 
1431 	if (sk->sk_state == TCP_NEW_SYN_RECV) {
1432 		struct request_sock *req = inet_reqsk(sk);
1433 		struct sock *nsk;
1434 
1435 		sk = req->rsk_listener;
1436 		tcp_v6_fill_cb(skb, hdr, th);
1437 		if (tcp_v6_inbound_md5_hash(sk, skb)) {
1438 			sk_drops_add(sk, skb);
1439 			reqsk_put(req);
1440 			goto discard_it;
1441 		}
1442 		if (unlikely(sk->sk_state != TCP_LISTEN)) {
1443 			inet_csk_reqsk_queue_drop_and_put(sk, req);
1444 			goto lookup;
1445 		}
1446 		sock_hold(sk);
1447 		refcounted = true;
1448 		nsk = tcp_check_req(sk, skb, req, false);
1449 		if (!nsk) {
1450 			reqsk_put(req);
1451 			goto discard_and_relse;
1452 		}
1453 		if (nsk == sk) {
1454 			reqsk_put(req);
1455 			tcp_v6_restore_cb(skb);
1456 		} else if (tcp_child_process(sk, nsk, skb)) {
1457 			tcp_v6_send_reset(nsk, skb);
1458 			goto discard_and_relse;
1459 		} else {
1460 			sock_put(sk);
1461 			return 0;
1462 		}
1463 	}
1464 	if (hdr->hop_limit < inet6_sk(sk)->min_hopcount) {
1465 		__NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP);
1466 		goto discard_and_relse;
1467 	}
1468 
1469 	if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb))
1470 		goto discard_and_relse;
1471 
1472 	tcp_v6_fill_cb(skb, hdr, th);
1473 
1474 	if (tcp_v6_inbound_md5_hash(sk, skb))
1475 		goto discard_and_relse;
1476 
1477 	if (tcp_filter(sk, skb))
1478 		goto discard_and_relse;
1479 	th = (const struct tcphdr *)skb->data;
1480 	hdr = ipv6_hdr(skb);
1481 
1482 	skb->dev = NULL;
1483 
1484 	if (sk->sk_state == TCP_LISTEN) {
1485 		ret = tcp_v6_do_rcv(sk, skb);
1486 		goto put_and_return;
1487 	}
1488 
1489 	sk_incoming_cpu_update(sk);
1490 
1491 	bh_lock_sock_nested(sk);
1492 	tcp_segs_in(tcp_sk(sk), skb);
1493 	ret = 0;
1494 	if (!sock_owned_by_user(sk)) {
1495 		if (!tcp_prequeue(sk, skb))
1496 			ret = tcp_v6_do_rcv(sk, skb);
1497 	} else if (tcp_add_backlog(sk, skb)) {
1498 		goto discard_and_relse;
1499 	}
1500 	bh_unlock_sock(sk);
1501 
1502 put_and_return:
1503 	if (refcounted)
1504 		sock_put(sk);
1505 	return ret ? -1 : 0;
1506 
1507 no_tcp_socket:
1508 	if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb))
1509 		goto discard_it;
1510 
1511 	tcp_v6_fill_cb(skb, hdr, th);
1512 
1513 	if (tcp_checksum_complete(skb)) {
1514 csum_error:
1515 		__TCP_INC_STATS(net, TCP_MIB_CSUMERRORS);
1516 bad_packet:
1517 		__TCP_INC_STATS(net, TCP_MIB_INERRS);
1518 	} else {
1519 		tcp_v6_send_reset(NULL, skb);
1520 	}
1521 
1522 discard_it:
1523 	kfree_skb(skb);
1524 	return 0;
1525 
1526 discard_and_relse:
1527 	sk_drops_add(sk, skb);
1528 	if (refcounted)
1529 		sock_put(sk);
1530 	goto discard_it;
1531 
1532 do_time_wait:
1533 	if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
1534 		inet_twsk_put(inet_twsk(sk));
1535 		goto discard_it;
1536 	}
1537 
1538 	tcp_v6_fill_cb(skb, hdr, th);
1539 
1540 	if (tcp_checksum_complete(skb)) {
1541 		inet_twsk_put(inet_twsk(sk));
1542 		goto csum_error;
1543 	}
1544 
1545 	switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) {
1546 	case TCP_TW_SYN:
1547 	{
1548 		struct sock *sk2;
1549 
1550 		sk2 = inet6_lookup_listener(dev_net(skb->dev), &tcp_hashinfo,
1551 					    skb, __tcp_hdrlen(th),
1552 					    &ipv6_hdr(skb)->saddr, th->source,
1553 					    &ipv6_hdr(skb)->daddr,
1554 					    ntohs(th->dest), tcp_v6_iif(skb));
1555 		if (sk2) {
1556 			struct inet_timewait_sock *tw = inet_twsk(sk);
1557 			inet_twsk_deschedule_put(tw);
1558 			sk = sk2;
1559 			tcp_v6_restore_cb(skb);
1560 			refcounted = false;
1561 			goto process;
1562 		}
1563 		/* Fall through to ACK */
1564 	}
1565 	case TCP_TW_ACK:
1566 		tcp_v6_timewait_ack(sk, skb);
1567 		break;
1568 	case TCP_TW_RST:
1569 		tcp_v6_restore_cb(skb);
1570 		tcp_v6_send_reset(sk, skb);
1571 		inet_twsk_deschedule_put(inet_twsk(sk));
1572 		goto discard_it;
1573 	case TCP_TW_SUCCESS:
1574 		;
1575 	}
1576 	goto discard_it;
1577 }
1578 
1579 static void tcp_v6_early_demux(struct sk_buff *skb)
1580 {
1581 	const struct ipv6hdr *hdr;
1582 	const struct tcphdr *th;
1583 	struct sock *sk;
1584 
1585 	if (skb->pkt_type != PACKET_HOST)
1586 		return;
1587 
1588 	if (!pskb_may_pull(skb, skb_transport_offset(skb) + sizeof(struct tcphdr)))
1589 		return;
1590 
1591 	hdr = ipv6_hdr(skb);
1592 	th = tcp_hdr(skb);
1593 
1594 	if (th->doff < sizeof(struct tcphdr) / 4)
1595 		return;
1596 
1597 	/* Note : We use inet6_iif() here, not tcp_v6_iif() */
1598 	sk = __inet6_lookup_established(dev_net(skb->dev), &tcp_hashinfo,
1599 					&hdr->saddr, th->source,
1600 					&hdr->daddr, ntohs(th->dest),
1601 					inet6_iif(skb));
1602 	if (sk) {
1603 		skb->sk = sk;
1604 		skb->destructor = sock_edemux;
1605 		if (sk_fullsock(sk)) {
1606 			struct dst_entry *dst = READ_ONCE(sk->sk_rx_dst);
1607 
1608 			if (dst)
1609 				dst = dst_check(dst, inet6_sk(sk)->rx_dst_cookie);
1610 			if (dst &&
1611 			    inet_sk(sk)->rx_dst_ifindex == skb->skb_iif)
1612 				skb_dst_set_noref(skb, dst);
1613 		}
1614 	}
1615 }
1616 
1617 static struct timewait_sock_ops tcp6_timewait_sock_ops = {
1618 	.twsk_obj_size	= sizeof(struct tcp6_timewait_sock),
1619 	.twsk_unique	= tcp_twsk_unique,
1620 	.twsk_destructor = tcp_twsk_destructor,
1621 };
1622 
1623 static const struct inet_connection_sock_af_ops ipv6_specific = {
1624 	.queue_xmit	   = inet6_csk_xmit,
1625 	.send_check	   = tcp_v6_send_check,
1626 	.rebuild_header	   = inet6_sk_rebuild_header,
1627 	.sk_rx_dst_set	   = inet6_sk_rx_dst_set,
1628 	.conn_request	   = tcp_v6_conn_request,
1629 	.syn_recv_sock	   = tcp_v6_syn_recv_sock,
1630 	.net_header_len	   = sizeof(struct ipv6hdr),
1631 	.net_frag_header_len = sizeof(struct frag_hdr),
1632 	.setsockopt	   = ipv6_setsockopt,
1633 	.getsockopt	   = ipv6_getsockopt,
1634 	.addr2sockaddr	   = inet6_csk_addr2sockaddr,
1635 	.sockaddr_len	   = sizeof(struct sockaddr_in6),
1636 #ifdef CONFIG_COMPAT
1637 	.compat_setsockopt = compat_ipv6_setsockopt,
1638 	.compat_getsockopt = compat_ipv6_getsockopt,
1639 #endif
1640 	.mtu_reduced	   = tcp_v6_mtu_reduced,
1641 };
1642 
1643 #ifdef CONFIG_TCP_MD5SIG
1644 static const struct tcp_sock_af_ops tcp_sock_ipv6_specific = {
1645 	.md5_lookup	=	tcp_v6_md5_lookup,
1646 	.calc_md5_hash	=	tcp_v6_md5_hash_skb,
1647 	.md5_parse	=	tcp_v6_parse_md5_keys,
1648 };
1649 #endif
1650 
1651 /*
1652  *	TCP over IPv4 via INET6 API
1653  */
1654 static const struct inet_connection_sock_af_ops ipv6_mapped = {
1655 	.queue_xmit	   = ip_queue_xmit,
1656 	.send_check	   = tcp_v4_send_check,
1657 	.rebuild_header	   = inet_sk_rebuild_header,
1658 	.sk_rx_dst_set	   = inet_sk_rx_dst_set,
1659 	.conn_request	   = tcp_v6_conn_request,
1660 	.syn_recv_sock	   = tcp_v6_syn_recv_sock,
1661 	.net_header_len	   = sizeof(struct iphdr),
1662 	.setsockopt	   = ipv6_setsockopt,
1663 	.getsockopt	   = ipv6_getsockopt,
1664 	.addr2sockaddr	   = inet6_csk_addr2sockaddr,
1665 	.sockaddr_len	   = sizeof(struct sockaddr_in6),
1666 #ifdef CONFIG_COMPAT
1667 	.compat_setsockopt = compat_ipv6_setsockopt,
1668 	.compat_getsockopt = compat_ipv6_getsockopt,
1669 #endif
1670 	.mtu_reduced	   = tcp_v4_mtu_reduced,
1671 };
1672 
1673 #ifdef CONFIG_TCP_MD5SIG
1674 static const struct tcp_sock_af_ops tcp_sock_ipv6_mapped_specific = {
1675 	.md5_lookup	=	tcp_v4_md5_lookup,
1676 	.calc_md5_hash	=	tcp_v4_md5_hash_skb,
1677 	.md5_parse	=	tcp_v6_parse_md5_keys,
1678 };
1679 #endif
1680 
1681 /* NOTE: A lot of things set to zero explicitly by call to
1682  *       sk_alloc() so need not be done here.
1683  */
1684 static int tcp_v6_init_sock(struct sock *sk)
1685 {
1686 	struct inet_connection_sock *icsk = inet_csk(sk);
1687 
1688 	tcp_init_sock(sk);
1689 
1690 	icsk->icsk_af_ops = &ipv6_specific;
1691 
1692 #ifdef CONFIG_TCP_MD5SIG
1693 	tcp_sk(sk)->af_specific = &tcp_sock_ipv6_specific;
1694 #endif
1695 
1696 	return 0;
1697 }
1698 
1699 static void tcp_v6_destroy_sock(struct sock *sk)
1700 {
1701 	tcp_v4_destroy_sock(sk);
1702 	inet6_destroy_sock(sk);
1703 }
1704 
1705 #ifdef CONFIG_PROC_FS
1706 /* Proc filesystem TCPv6 sock list dumping. */
1707 static void get_openreq6(struct seq_file *seq,
1708 			 const struct request_sock *req, int i)
1709 {
1710 	long ttd = req->rsk_timer.expires - jiffies;
1711 	const struct in6_addr *src = &inet_rsk(req)->ir_v6_loc_addr;
1712 	const struct in6_addr *dest = &inet_rsk(req)->ir_v6_rmt_addr;
1713 
1714 	if (ttd < 0)
1715 		ttd = 0;
1716 
1717 	seq_printf(seq,
1718 		   "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
1719 		   "%02X %08X:%08X %02X:%08lX %08X %5u %8d %d %d %pK\n",
1720 		   i,
1721 		   src->s6_addr32[0], src->s6_addr32[1],
1722 		   src->s6_addr32[2], src->s6_addr32[3],
1723 		   inet_rsk(req)->ir_num,
1724 		   dest->s6_addr32[0], dest->s6_addr32[1],
1725 		   dest->s6_addr32[2], dest->s6_addr32[3],
1726 		   ntohs(inet_rsk(req)->ir_rmt_port),
1727 		   TCP_SYN_RECV,
1728 		   0, 0, /* could print option size, but that is af dependent. */
1729 		   1,   /* timers active (only the expire timer) */
1730 		   jiffies_to_clock_t(ttd),
1731 		   req->num_timeout,
1732 		   from_kuid_munged(seq_user_ns(seq),
1733 				    sock_i_uid(req->rsk_listener)),
1734 		   0,  /* non standard timer */
1735 		   0, /* open_requests have no inode */
1736 		   0, req);
1737 }
1738 
1739 static void get_tcp6_sock(struct seq_file *seq, struct sock *sp, int i)
1740 {
1741 	const struct in6_addr *dest, *src;
1742 	__u16 destp, srcp;
1743 	int timer_active;
1744 	unsigned long timer_expires;
1745 	const struct inet_sock *inet = inet_sk(sp);
1746 	const struct tcp_sock *tp = tcp_sk(sp);
1747 	const struct inet_connection_sock *icsk = inet_csk(sp);
1748 	const struct fastopen_queue *fastopenq = &icsk->icsk_accept_queue.fastopenq;
1749 	int rx_queue;
1750 	int state;
1751 
1752 	dest  = &sp->sk_v6_daddr;
1753 	src   = &sp->sk_v6_rcv_saddr;
1754 	destp = ntohs(inet->inet_dport);
1755 	srcp  = ntohs(inet->inet_sport);
1756 
1757 	if (icsk->icsk_pending == ICSK_TIME_RETRANS ||
1758 	    icsk->icsk_pending == ICSK_TIME_REO_TIMEOUT ||
1759 	    icsk->icsk_pending == ICSK_TIME_LOSS_PROBE) {
1760 		timer_active	= 1;
1761 		timer_expires	= icsk->icsk_timeout;
1762 	} else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
1763 		timer_active	= 4;
1764 		timer_expires	= icsk->icsk_timeout;
1765 	} else if (timer_pending(&sp->sk_timer)) {
1766 		timer_active	= 2;
1767 		timer_expires	= sp->sk_timer.expires;
1768 	} else {
1769 		timer_active	= 0;
1770 		timer_expires = jiffies;
1771 	}
1772 
1773 	state = sk_state_load(sp);
1774 	if (state == TCP_LISTEN)
1775 		rx_queue = sp->sk_ack_backlog;
1776 	else
1777 		/* Because we don't lock the socket,
1778 		 * we might find a transient negative value.
1779 		 */
1780 		rx_queue = max_t(int, tp->rcv_nxt - tp->copied_seq, 0);
1781 
1782 	seq_printf(seq,
1783 		   "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
1784 		   "%02X %08X:%08X %02X:%08lX %08X %5u %8d %lu %d %pK %lu %lu %u %u %d\n",
1785 		   i,
1786 		   src->s6_addr32[0], src->s6_addr32[1],
1787 		   src->s6_addr32[2], src->s6_addr32[3], srcp,
1788 		   dest->s6_addr32[0], dest->s6_addr32[1],
1789 		   dest->s6_addr32[2], dest->s6_addr32[3], destp,
1790 		   state,
1791 		   tp->write_seq - tp->snd_una,
1792 		   rx_queue,
1793 		   timer_active,
1794 		   jiffies_delta_to_clock_t(timer_expires - jiffies),
1795 		   icsk->icsk_retransmits,
1796 		   from_kuid_munged(seq_user_ns(seq), sock_i_uid(sp)),
1797 		   icsk->icsk_probes_out,
1798 		   sock_i_ino(sp),
1799 		   atomic_read(&sp->sk_refcnt), sp,
1800 		   jiffies_to_clock_t(icsk->icsk_rto),
1801 		   jiffies_to_clock_t(icsk->icsk_ack.ato),
1802 		   (icsk->icsk_ack.quick << 1) | icsk->icsk_ack.pingpong,
1803 		   tp->snd_cwnd,
1804 		   state == TCP_LISTEN ?
1805 			fastopenq->max_qlen :
1806 			(tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh)
1807 		   );
1808 }
1809 
1810 static void get_timewait6_sock(struct seq_file *seq,
1811 			       struct inet_timewait_sock *tw, int i)
1812 {
1813 	long delta = tw->tw_timer.expires - jiffies;
1814 	const struct in6_addr *dest, *src;
1815 	__u16 destp, srcp;
1816 
1817 	dest = &tw->tw_v6_daddr;
1818 	src  = &tw->tw_v6_rcv_saddr;
1819 	destp = ntohs(tw->tw_dport);
1820 	srcp  = ntohs(tw->tw_sport);
1821 
1822 	seq_printf(seq,
1823 		   "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
1824 		   "%02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK\n",
1825 		   i,
1826 		   src->s6_addr32[0], src->s6_addr32[1],
1827 		   src->s6_addr32[2], src->s6_addr32[3], srcp,
1828 		   dest->s6_addr32[0], dest->s6_addr32[1],
1829 		   dest->s6_addr32[2], dest->s6_addr32[3], destp,
1830 		   tw->tw_substate, 0, 0,
1831 		   3, jiffies_delta_to_clock_t(delta), 0, 0, 0, 0,
1832 		   atomic_read(&tw->tw_refcnt), tw);
1833 }
1834 
1835 static int tcp6_seq_show(struct seq_file *seq, void *v)
1836 {
1837 	struct tcp_iter_state *st;
1838 	struct sock *sk = v;
1839 
1840 	if (v == SEQ_START_TOKEN) {
1841 		seq_puts(seq,
1842 			 "  sl  "
1843 			 "local_address                         "
1844 			 "remote_address                        "
1845 			 "st tx_queue rx_queue tr tm->when retrnsmt"
1846 			 "   uid  timeout inode\n");
1847 		goto out;
1848 	}
1849 	st = seq->private;
1850 
1851 	if (sk->sk_state == TCP_TIME_WAIT)
1852 		get_timewait6_sock(seq, v, st->num);
1853 	else if (sk->sk_state == TCP_NEW_SYN_RECV)
1854 		get_openreq6(seq, v, st->num);
1855 	else
1856 		get_tcp6_sock(seq, v, st->num);
1857 out:
1858 	return 0;
1859 }
1860 
1861 static const struct file_operations tcp6_afinfo_seq_fops = {
1862 	.owner   = THIS_MODULE,
1863 	.open    = tcp_seq_open,
1864 	.read    = seq_read,
1865 	.llseek  = seq_lseek,
1866 	.release = seq_release_net
1867 };
1868 
1869 static struct tcp_seq_afinfo tcp6_seq_afinfo = {
1870 	.name		= "tcp6",
1871 	.family		= AF_INET6,
1872 	.seq_fops	= &tcp6_afinfo_seq_fops,
1873 	.seq_ops	= {
1874 		.show		= tcp6_seq_show,
1875 	},
1876 };
1877 
1878 int __net_init tcp6_proc_init(struct net *net)
1879 {
1880 	return tcp_proc_register(net, &tcp6_seq_afinfo);
1881 }
1882 
1883 void tcp6_proc_exit(struct net *net)
1884 {
1885 	tcp_proc_unregister(net, &tcp6_seq_afinfo);
1886 }
1887 #endif
1888 
1889 struct proto tcpv6_prot = {
1890 	.name			= "TCPv6",
1891 	.owner			= THIS_MODULE,
1892 	.close			= tcp_close,
1893 	.connect		= tcp_v6_connect,
1894 	.disconnect		= tcp_disconnect,
1895 	.accept			= inet_csk_accept,
1896 	.ioctl			= tcp_ioctl,
1897 	.init			= tcp_v6_init_sock,
1898 	.destroy		= tcp_v6_destroy_sock,
1899 	.shutdown		= tcp_shutdown,
1900 	.setsockopt		= tcp_setsockopt,
1901 	.getsockopt		= tcp_getsockopt,
1902 	.keepalive		= tcp_set_keepalive,
1903 	.recvmsg		= tcp_recvmsg,
1904 	.sendmsg		= tcp_sendmsg,
1905 	.sendpage		= tcp_sendpage,
1906 	.backlog_rcv		= tcp_v6_do_rcv,
1907 	.release_cb		= tcp_release_cb,
1908 	.hash			= inet6_hash,
1909 	.unhash			= inet_unhash,
1910 	.get_port		= inet_csk_get_port,
1911 	.enter_memory_pressure	= tcp_enter_memory_pressure,
1912 	.stream_memory_free	= tcp_stream_memory_free,
1913 	.sockets_allocated	= &tcp_sockets_allocated,
1914 	.memory_allocated	= &tcp_memory_allocated,
1915 	.memory_pressure	= &tcp_memory_pressure,
1916 	.orphan_count		= &tcp_orphan_count,
1917 	.sysctl_mem		= sysctl_tcp_mem,
1918 	.sysctl_wmem		= sysctl_tcp_wmem,
1919 	.sysctl_rmem		= sysctl_tcp_rmem,
1920 	.max_header		= MAX_TCP_HEADER,
1921 	.obj_size		= sizeof(struct tcp6_sock),
1922 	.slab_flags		= SLAB_DESTROY_BY_RCU,
1923 	.twsk_prot		= &tcp6_timewait_sock_ops,
1924 	.rsk_prot		= &tcp6_request_sock_ops,
1925 	.h.hashinfo		= &tcp_hashinfo,
1926 	.no_autobind		= true,
1927 #ifdef CONFIG_COMPAT
1928 	.compat_setsockopt	= compat_tcp_setsockopt,
1929 	.compat_getsockopt	= compat_tcp_getsockopt,
1930 #endif
1931 	.diag_destroy		= tcp_abort,
1932 };
1933 
1934 static const struct inet6_protocol tcpv6_protocol = {
1935 	.early_demux	=	tcp_v6_early_demux,
1936 	.handler	=	tcp_v6_rcv,
1937 	.err_handler	=	tcp_v6_err,
1938 	.flags		=	INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
1939 };
1940 
1941 static struct inet_protosw tcpv6_protosw = {
1942 	.type		=	SOCK_STREAM,
1943 	.protocol	=	IPPROTO_TCP,
1944 	.prot		=	&tcpv6_prot,
1945 	.ops		=	&inet6_stream_ops,
1946 	.flags		=	INET_PROTOSW_PERMANENT |
1947 				INET_PROTOSW_ICSK,
1948 };
1949 
1950 static int __net_init tcpv6_net_init(struct net *net)
1951 {
1952 	return inet_ctl_sock_create(&net->ipv6.tcp_sk, PF_INET6,
1953 				    SOCK_RAW, IPPROTO_TCP, net);
1954 }
1955 
1956 static void __net_exit tcpv6_net_exit(struct net *net)
1957 {
1958 	inet_ctl_sock_destroy(net->ipv6.tcp_sk);
1959 }
1960 
1961 static void __net_exit tcpv6_net_exit_batch(struct list_head *net_exit_list)
1962 {
1963 	inet_twsk_purge(&tcp_hashinfo, AF_INET6);
1964 }
1965 
1966 static struct pernet_operations tcpv6_net_ops = {
1967 	.init	    = tcpv6_net_init,
1968 	.exit	    = tcpv6_net_exit,
1969 	.exit_batch = tcpv6_net_exit_batch,
1970 };
1971 
1972 int __init tcpv6_init(void)
1973 {
1974 	int ret;
1975 
1976 	ret = inet6_add_protocol(&tcpv6_protocol, IPPROTO_TCP);
1977 	if (ret)
1978 		goto out;
1979 
1980 	/* register inet6 protocol */
1981 	ret = inet6_register_protosw(&tcpv6_protosw);
1982 	if (ret)
1983 		goto out_tcpv6_protocol;
1984 
1985 	ret = register_pernet_subsys(&tcpv6_net_ops);
1986 	if (ret)
1987 		goto out_tcpv6_protosw;
1988 out:
1989 	return ret;
1990 
1991 out_tcpv6_protosw:
1992 	inet6_unregister_protosw(&tcpv6_protosw);
1993 out_tcpv6_protocol:
1994 	inet6_del_protocol(&tcpv6_protocol, IPPROTO_TCP);
1995 	goto out;
1996 }
1997 
1998 void tcpv6_exit(void)
1999 {
2000 	unregister_pernet_subsys(&tcpv6_net_ops);
2001 	inet6_unregister_protosw(&tcpv6_protosw);
2002 	inet6_del_protocol(&tcpv6_protocol, IPPROTO_TCP);
2003 }
2004