xref: /openbmc/linux/net/ipv6/tcp_ipv6.c (revision b6bec26c)
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 
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/netdma.h>
63 #include <net/inet_common.h>
64 #include <net/secure_seq.h>
65 #include <net/tcp_memcontrol.h>
66 
67 #include <asm/uaccess.h>
68 
69 #include <linux/proc_fs.h>
70 #include <linux/seq_file.h>
71 
72 #include <linux/crypto.h>
73 #include <linux/scatterlist.h>
74 
75 static void	tcp_v6_send_reset(struct sock *sk, struct sk_buff *skb);
76 static void	tcp_v6_reqsk_send_ack(struct sock *sk, struct sk_buff *skb,
77 				      struct request_sock *req);
78 
79 static int	tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb);
80 
81 static const struct inet_connection_sock_af_ops ipv6_mapped;
82 static const struct inet_connection_sock_af_ops ipv6_specific;
83 #ifdef CONFIG_TCP_MD5SIG
84 static const struct tcp_sock_af_ops tcp_sock_ipv6_specific;
85 static const struct tcp_sock_af_ops tcp_sock_ipv6_mapped_specific;
86 #else
87 static struct tcp_md5sig_key *tcp_v6_md5_do_lookup(struct sock *sk,
88 						   const struct in6_addr *addr)
89 {
90 	return NULL;
91 }
92 #endif
93 
94 static void inet6_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb)
95 {
96 	struct dst_entry *dst = skb_dst(skb);
97 	const struct rt6_info *rt = (const struct rt6_info *)dst;
98 
99 	dst_hold(dst);
100 	sk->sk_rx_dst = dst;
101 	inet_sk(sk)->rx_dst_ifindex = skb->skb_iif;
102 	if (rt->rt6i_node)
103 		inet6_sk(sk)->rx_dst_cookie = rt->rt6i_node->fn_sernum;
104 }
105 
106 static void tcp_v6_hash(struct sock *sk)
107 {
108 	if (sk->sk_state != TCP_CLOSE) {
109 		if (inet_csk(sk)->icsk_af_ops == &ipv6_mapped) {
110 			tcp_prot.hash(sk);
111 			return;
112 		}
113 		local_bh_disable();
114 		__inet6_hash(sk, NULL);
115 		local_bh_enable();
116 	}
117 }
118 
119 static __u32 tcp_v6_init_sequence(const struct sk_buff *skb)
120 {
121 	return secure_tcpv6_sequence_number(ipv6_hdr(skb)->daddr.s6_addr32,
122 					    ipv6_hdr(skb)->saddr.s6_addr32,
123 					    tcp_hdr(skb)->dest,
124 					    tcp_hdr(skb)->source);
125 }
126 
127 static int tcp_v6_connect(struct sock *sk, struct sockaddr *uaddr,
128 			  int addr_len)
129 {
130 	struct sockaddr_in6 *usin = (struct sockaddr_in6 *) uaddr;
131 	struct inet_sock *inet = inet_sk(sk);
132 	struct inet_connection_sock *icsk = inet_csk(sk);
133 	struct ipv6_pinfo *np = inet6_sk(sk);
134 	struct tcp_sock *tp = tcp_sk(sk);
135 	struct in6_addr *saddr = NULL, *final_p, final;
136 	struct rt6_info *rt;
137 	struct flowi6 fl6;
138 	struct dst_entry *dst;
139 	int addr_type;
140 	int err;
141 
142 	if (addr_len < SIN6_LEN_RFC2133)
143 		return -EINVAL;
144 
145 	if (usin->sin6_family != AF_INET6)
146 		return -EAFNOSUPPORT;
147 
148 	memset(&fl6, 0, sizeof(fl6));
149 
150 	if (np->sndflow) {
151 		fl6.flowlabel = usin->sin6_flowinfo&IPV6_FLOWINFO_MASK;
152 		IP6_ECN_flow_init(fl6.flowlabel);
153 		if (fl6.flowlabel&IPV6_FLOWLABEL_MASK) {
154 			struct ip6_flowlabel *flowlabel;
155 			flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
156 			if (flowlabel == NULL)
157 				return -EINVAL;
158 			usin->sin6_addr = flowlabel->dst;
159 			fl6_sock_release(flowlabel);
160 		}
161 	}
162 
163 	/*
164 	 *	connect() to INADDR_ANY means loopback (BSD'ism).
165 	 */
166 
167 	if(ipv6_addr_any(&usin->sin6_addr))
168 		usin->sin6_addr.s6_addr[15] = 0x1;
169 
170 	addr_type = ipv6_addr_type(&usin->sin6_addr);
171 
172 	if(addr_type & IPV6_ADDR_MULTICAST)
173 		return -ENETUNREACH;
174 
175 	if (addr_type&IPV6_ADDR_LINKLOCAL) {
176 		if (addr_len >= sizeof(struct sockaddr_in6) &&
177 		    usin->sin6_scope_id) {
178 			/* If interface is set while binding, indices
179 			 * must coincide.
180 			 */
181 			if (sk->sk_bound_dev_if &&
182 			    sk->sk_bound_dev_if != usin->sin6_scope_id)
183 				return -EINVAL;
184 
185 			sk->sk_bound_dev_if = usin->sin6_scope_id;
186 		}
187 
188 		/* Connect to link-local address requires an interface */
189 		if (!sk->sk_bound_dev_if)
190 			return -EINVAL;
191 	}
192 
193 	if (tp->rx_opt.ts_recent_stamp &&
194 	    !ipv6_addr_equal(&np->daddr, &usin->sin6_addr)) {
195 		tp->rx_opt.ts_recent = 0;
196 		tp->rx_opt.ts_recent_stamp = 0;
197 		tp->write_seq = 0;
198 	}
199 
200 	np->daddr = usin->sin6_addr;
201 	np->flow_label = fl6.flowlabel;
202 
203 	/*
204 	 *	TCP over IPv4
205 	 */
206 
207 	if (addr_type == IPV6_ADDR_MAPPED) {
208 		u32 exthdrlen = icsk->icsk_ext_hdr_len;
209 		struct sockaddr_in sin;
210 
211 		SOCK_DEBUG(sk, "connect: ipv4 mapped\n");
212 
213 		if (__ipv6_only_sock(sk))
214 			return -ENETUNREACH;
215 
216 		sin.sin_family = AF_INET;
217 		sin.sin_port = usin->sin6_port;
218 		sin.sin_addr.s_addr = usin->sin6_addr.s6_addr32[3];
219 
220 		icsk->icsk_af_ops = &ipv6_mapped;
221 		sk->sk_backlog_rcv = tcp_v4_do_rcv;
222 #ifdef CONFIG_TCP_MD5SIG
223 		tp->af_specific = &tcp_sock_ipv6_mapped_specific;
224 #endif
225 
226 		err = tcp_v4_connect(sk, (struct sockaddr *)&sin, sizeof(sin));
227 
228 		if (err) {
229 			icsk->icsk_ext_hdr_len = exthdrlen;
230 			icsk->icsk_af_ops = &ipv6_specific;
231 			sk->sk_backlog_rcv = tcp_v6_do_rcv;
232 #ifdef CONFIG_TCP_MD5SIG
233 			tp->af_specific = &tcp_sock_ipv6_specific;
234 #endif
235 			goto failure;
236 		} else {
237 			ipv6_addr_set_v4mapped(inet->inet_saddr, &np->saddr);
238 			ipv6_addr_set_v4mapped(inet->inet_rcv_saddr,
239 					       &np->rcv_saddr);
240 		}
241 
242 		return err;
243 	}
244 
245 	if (!ipv6_addr_any(&np->rcv_saddr))
246 		saddr = &np->rcv_saddr;
247 
248 	fl6.flowi6_proto = IPPROTO_TCP;
249 	fl6.daddr = np->daddr;
250 	fl6.saddr = saddr ? *saddr : np->saddr;
251 	fl6.flowi6_oif = sk->sk_bound_dev_if;
252 	fl6.flowi6_mark = sk->sk_mark;
253 	fl6.fl6_dport = usin->sin6_port;
254 	fl6.fl6_sport = inet->inet_sport;
255 
256 	final_p = fl6_update_dst(&fl6, np->opt, &final);
257 
258 	security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));
259 
260 	dst = ip6_dst_lookup_flow(sk, &fl6, final_p, true);
261 	if (IS_ERR(dst)) {
262 		err = PTR_ERR(dst);
263 		goto failure;
264 	}
265 
266 	if (saddr == NULL) {
267 		saddr = &fl6.saddr;
268 		np->rcv_saddr = *saddr;
269 	}
270 
271 	/* set the source address */
272 	np->saddr = *saddr;
273 	inet->inet_rcv_saddr = LOOPBACK4_IPV6;
274 
275 	sk->sk_gso_type = SKB_GSO_TCPV6;
276 	__ip6_dst_store(sk, dst, NULL, NULL);
277 
278 	rt = (struct rt6_info *) dst;
279 	if (tcp_death_row.sysctl_tw_recycle &&
280 	    !tp->rx_opt.ts_recent_stamp &&
281 	    ipv6_addr_equal(&rt->rt6i_dst.addr, &np->daddr))
282 		tcp_fetch_timewait_stamp(sk, dst);
283 
284 	icsk->icsk_ext_hdr_len = 0;
285 	if (np->opt)
286 		icsk->icsk_ext_hdr_len = (np->opt->opt_flen +
287 					  np->opt->opt_nflen);
288 
289 	tp->rx_opt.mss_clamp = IPV6_MIN_MTU - sizeof(struct tcphdr) - sizeof(struct ipv6hdr);
290 
291 	inet->inet_dport = usin->sin6_port;
292 
293 	tcp_set_state(sk, TCP_SYN_SENT);
294 	err = inet6_hash_connect(&tcp_death_row, sk);
295 	if (err)
296 		goto late_failure;
297 
298 	if (!tp->write_seq && likely(!tp->repair))
299 		tp->write_seq = secure_tcpv6_sequence_number(np->saddr.s6_addr32,
300 							     np->daddr.s6_addr32,
301 							     inet->inet_sport,
302 							     inet->inet_dport);
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 	__sk_dst_reset(sk);
313 failure:
314 	inet->inet_dport = 0;
315 	sk->sk_route_caps = 0;
316 	return err;
317 }
318 
319 static void tcp_v6_mtu_reduced(struct sock *sk)
320 {
321 	struct dst_entry *dst;
322 
323 	if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE))
324 		return;
325 
326 	dst = inet6_csk_update_pmtu(sk, tcp_sk(sk)->mtu_info);
327 	if (!dst)
328 		return;
329 
330 	if (inet_csk(sk)->icsk_pmtu_cookie > dst_mtu(dst)) {
331 		tcp_sync_mss(sk, dst_mtu(dst));
332 		tcp_simple_retransmit(sk);
333 	}
334 }
335 
336 static void tcp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
337 		u8 type, u8 code, int offset, __be32 info)
338 {
339 	const struct ipv6hdr *hdr = (const struct ipv6hdr*)skb->data;
340 	const struct tcphdr *th = (struct tcphdr *)(skb->data+offset);
341 	struct ipv6_pinfo *np;
342 	struct sock *sk;
343 	int err;
344 	struct tcp_sock *tp;
345 	__u32 seq;
346 	struct net *net = dev_net(skb->dev);
347 
348 	sk = inet6_lookup(net, &tcp_hashinfo, &hdr->daddr,
349 			th->dest, &hdr->saddr, th->source, skb->dev->ifindex);
350 
351 	if (sk == NULL) {
352 		ICMP6_INC_STATS_BH(net, __in6_dev_get(skb->dev),
353 				   ICMP6_MIB_INERRORS);
354 		return;
355 	}
356 
357 	if (sk->sk_state == TCP_TIME_WAIT) {
358 		inet_twsk_put(inet_twsk(sk));
359 		return;
360 	}
361 
362 	bh_lock_sock(sk);
363 	if (sock_owned_by_user(sk) && type != ICMPV6_PKT_TOOBIG)
364 		NET_INC_STATS_BH(net, LINUX_MIB_LOCKDROPPEDICMPS);
365 
366 	if (sk->sk_state == TCP_CLOSE)
367 		goto out;
368 
369 	if (ipv6_hdr(skb)->hop_limit < inet6_sk(sk)->min_hopcount) {
370 		NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP);
371 		goto out;
372 	}
373 
374 	tp = tcp_sk(sk);
375 	seq = ntohl(th->seq);
376 	if (sk->sk_state != TCP_LISTEN &&
377 	    !between(seq, tp->snd_una, tp->snd_nxt)) {
378 		NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
379 		goto out;
380 	}
381 
382 	np = inet6_sk(sk);
383 
384 	if (type == NDISC_REDIRECT) {
385 		struct dst_entry *dst = __sk_dst_check(sk, np->dst_cookie);
386 
387 		if (dst)
388 			dst->ops->redirect(dst, sk, skb);
389 	}
390 
391 	if (type == ICMPV6_PKT_TOOBIG) {
392 		tp->mtu_info = ntohl(info);
393 		if (!sock_owned_by_user(sk))
394 			tcp_v6_mtu_reduced(sk);
395 		else if (!test_and_set_bit(TCP_MTU_REDUCED_DEFERRED,
396 					   &tp->tsq_flags))
397 			sock_hold(sk);
398 		goto out;
399 	}
400 
401 	icmpv6_err_convert(type, code, &err);
402 
403 	/* Might be for an request_sock */
404 	switch (sk->sk_state) {
405 		struct request_sock *req, **prev;
406 	case TCP_LISTEN:
407 		if (sock_owned_by_user(sk))
408 			goto out;
409 
410 		req = inet6_csk_search_req(sk, &prev, th->dest, &hdr->daddr,
411 					   &hdr->saddr, inet6_iif(skb));
412 		if (!req)
413 			goto out;
414 
415 		/* ICMPs are not backlogged, hence we cannot get
416 		 * an established socket here.
417 		 */
418 		WARN_ON(req->sk != NULL);
419 
420 		if (seq != tcp_rsk(req)->snt_isn) {
421 			NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
422 			goto out;
423 		}
424 
425 		inet_csk_reqsk_queue_drop(sk, req, prev);
426 		NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
427 		goto out;
428 
429 	case TCP_SYN_SENT:
430 	case TCP_SYN_RECV:  /* Cannot happen.
431 			       It can, it SYNs are crossed. --ANK */
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(struct sock *sk, struct dst_entry *dst,
455 			      struct flowi6 *fl6,
456 			      struct request_sock *req,
457 			      struct request_values *rvp,
458 			      u16 queue_mapping)
459 {
460 	struct inet6_request_sock *treq = inet6_rsk(req);
461 	struct ipv6_pinfo *np = inet6_sk(sk);
462 	struct sk_buff * skb;
463 	int err = -ENOMEM;
464 
465 	/* First, grab a route. */
466 	if (!dst && (dst = inet6_csk_route_req(sk, fl6, req)) == NULL)
467 		goto done;
468 
469 	skb = tcp_make_synack(sk, dst, req, rvp, NULL);
470 
471 	if (skb) {
472 		__tcp_v6_send_check(skb, &treq->loc_addr, &treq->rmt_addr);
473 
474 		fl6->daddr = treq->rmt_addr;
475 		skb_set_queue_mapping(skb, queue_mapping);
476 		err = ip6_xmit(sk, skb, fl6, np->opt, np->tclass);
477 		err = net_xmit_eval(err);
478 	}
479 
480 done:
481 	return err;
482 }
483 
484 static int tcp_v6_rtx_synack(struct sock *sk, struct request_sock *req,
485 			     struct request_values *rvp)
486 {
487 	struct flowi6 fl6;
488 	int res;
489 
490 	res = tcp_v6_send_synack(sk, NULL, &fl6, req, rvp, 0);
491 	if (!res)
492 		TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_RETRANSSEGS);
493 	return res;
494 }
495 
496 static void tcp_v6_reqsk_destructor(struct request_sock *req)
497 {
498 	kfree_skb(inet6_rsk(req)->pktopts);
499 }
500 
501 #ifdef CONFIG_TCP_MD5SIG
502 static struct tcp_md5sig_key *tcp_v6_md5_do_lookup(struct sock *sk,
503 						   const struct in6_addr *addr)
504 {
505 	return tcp_md5_do_lookup(sk, (union tcp_md5_addr *)addr, AF_INET6);
506 }
507 
508 static struct tcp_md5sig_key *tcp_v6_md5_lookup(struct sock *sk,
509 						struct sock *addr_sk)
510 {
511 	return tcp_v6_md5_do_lookup(sk, &inet6_sk(addr_sk)->daddr);
512 }
513 
514 static struct tcp_md5sig_key *tcp_v6_reqsk_md5_lookup(struct sock *sk,
515 						      struct request_sock *req)
516 {
517 	return tcp_v6_md5_do_lookup(sk, &inet6_rsk(req)->rmt_addr);
518 }
519 
520 static int tcp_v6_parse_md5_keys (struct sock *sk, char __user *optval,
521 				  int optlen)
522 {
523 	struct tcp_md5sig cmd;
524 	struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)&cmd.tcpm_addr;
525 
526 	if (optlen < sizeof(cmd))
527 		return -EINVAL;
528 
529 	if (copy_from_user(&cmd, optval, sizeof(cmd)))
530 		return -EFAULT;
531 
532 	if (sin6->sin6_family != AF_INET6)
533 		return -EINVAL;
534 
535 	if (!cmd.tcpm_keylen) {
536 		if (ipv6_addr_v4mapped(&sin6->sin6_addr))
537 			return tcp_md5_do_del(sk, (union tcp_md5_addr *)&sin6->sin6_addr.s6_addr32[3],
538 					      AF_INET);
539 		return tcp_md5_do_del(sk, (union tcp_md5_addr *)&sin6->sin6_addr,
540 				      AF_INET6);
541 	}
542 
543 	if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN)
544 		return -EINVAL;
545 
546 	if (ipv6_addr_v4mapped(&sin6->sin6_addr))
547 		return tcp_md5_do_add(sk, (union tcp_md5_addr *)&sin6->sin6_addr.s6_addr32[3],
548 				      AF_INET, cmd.tcpm_key, cmd.tcpm_keylen, GFP_KERNEL);
549 
550 	return tcp_md5_do_add(sk, (union tcp_md5_addr *)&sin6->sin6_addr,
551 			      AF_INET6, cmd.tcpm_key, cmd.tcpm_keylen, GFP_KERNEL);
552 }
553 
554 static int tcp_v6_md5_hash_pseudoheader(struct tcp_md5sig_pool *hp,
555 					const struct in6_addr *daddr,
556 					const struct in6_addr *saddr, int nbytes)
557 {
558 	struct tcp6_pseudohdr *bp;
559 	struct scatterlist sg;
560 
561 	bp = &hp->md5_blk.ip6;
562 	/* 1. TCP pseudo-header (RFC2460) */
563 	bp->saddr = *saddr;
564 	bp->daddr = *daddr;
565 	bp->protocol = cpu_to_be32(IPPROTO_TCP);
566 	bp->len = cpu_to_be32(nbytes);
567 
568 	sg_init_one(&sg, bp, sizeof(*bp));
569 	return crypto_hash_update(&hp->md5_desc, &sg, sizeof(*bp));
570 }
571 
572 static int tcp_v6_md5_hash_hdr(char *md5_hash, struct tcp_md5sig_key *key,
573 			       const struct in6_addr *daddr, struct in6_addr *saddr,
574 			       const struct tcphdr *th)
575 {
576 	struct tcp_md5sig_pool *hp;
577 	struct hash_desc *desc;
578 
579 	hp = tcp_get_md5sig_pool();
580 	if (!hp)
581 		goto clear_hash_noput;
582 	desc = &hp->md5_desc;
583 
584 	if (crypto_hash_init(desc))
585 		goto clear_hash;
586 	if (tcp_v6_md5_hash_pseudoheader(hp, daddr, saddr, th->doff << 2))
587 		goto clear_hash;
588 	if (tcp_md5_hash_header(hp, th))
589 		goto clear_hash;
590 	if (tcp_md5_hash_key(hp, key))
591 		goto clear_hash;
592 	if (crypto_hash_final(desc, md5_hash))
593 		goto clear_hash;
594 
595 	tcp_put_md5sig_pool();
596 	return 0;
597 
598 clear_hash:
599 	tcp_put_md5sig_pool();
600 clear_hash_noput:
601 	memset(md5_hash, 0, 16);
602 	return 1;
603 }
604 
605 static int tcp_v6_md5_hash_skb(char *md5_hash, struct tcp_md5sig_key *key,
606 			       const struct sock *sk,
607 			       const struct request_sock *req,
608 			       const struct sk_buff *skb)
609 {
610 	const struct in6_addr *saddr, *daddr;
611 	struct tcp_md5sig_pool *hp;
612 	struct hash_desc *desc;
613 	const struct tcphdr *th = tcp_hdr(skb);
614 
615 	if (sk) {
616 		saddr = &inet6_sk(sk)->saddr;
617 		daddr = &inet6_sk(sk)->daddr;
618 	} else if (req) {
619 		saddr = &inet6_rsk(req)->loc_addr;
620 		daddr = &inet6_rsk(req)->rmt_addr;
621 	} else {
622 		const struct ipv6hdr *ip6h = ipv6_hdr(skb);
623 		saddr = &ip6h->saddr;
624 		daddr = &ip6h->daddr;
625 	}
626 
627 	hp = tcp_get_md5sig_pool();
628 	if (!hp)
629 		goto clear_hash_noput;
630 	desc = &hp->md5_desc;
631 
632 	if (crypto_hash_init(desc))
633 		goto clear_hash;
634 
635 	if (tcp_v6_md5_hash_pseudoheader(hp, daddr, saddr, skb->len))
636 		goto clear_hash;
637 	if (tcp_md5_hash_header(hp, th))
638 		goto clear_hash;
639 	if (tcp_md5_hash_skb_data(hp, skb, th->doff << 2))
640 		goto clear_hash;
641 	if (tcp_md5_hash_key(hp, key))
642 		goto clear_hash;
643 	if (crypto_hash_final(desc, md5_hash))
644 		goto clear_hash;
645 
646 	tcp_put_md5sig_pool();
647 	return 0;
648 
649 clear_hash:
650 	tcp_put_md5sig_pool();
651 clear_hash_noput:
652 	memset(md5_hash, 0, 16);
653 	return 1;
654 }
655 
656 static int tcp_v6_inbound_md5_hash(struct sock *sk, const struct sk_buff *skb)
657 {
658 	const __u8 *hash_location = NULL;
659 	struct tcp_md5sig_key *hash_expected;
660 	const struct ipv6hdr *ip6h = ipv6_hdr(skb);
661 	const struct tcphdr *th = tcp_hdr(skb);
662 	int genhash;
663 	u8 newhash[16];
664 
665 	hash_expected = tcp_v6_md5_do_lookup(sk, &ip6h->saddr);
666 	hash_location = tcp_parse_md5sig_option(th);
667 
668 	/* We've parsed the options - do we have a hash? */
669 	if (!hash_expected && !hash_location)
670 		return 0;
671 
672 	if (hash_expected && !hash_location) {
673 		NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5NOTFOUND);
674 		return 1;
675 	}
676 
677 	if (!hash_expected && hash_location) {
678 		NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5UNEXPECTED);
679 		return 1;
680 	}
681 
682 	/* check the signature */
683 	genhash = tcp_v6_md5_hash_skb(newhash,
684 				      hash_expected,
685 				      NULL, NULL, skb);
686 
687 	if (genhash || memcmp(hash_location, newhash, 16) != 0) {
688 		net_info_ratelimited("MD5 Hash %s for [%pI6c]:%u->[%pI6c]:%u\n",
689 				     genhash ? "failed" : "mismatch",
690 				     &ip6h->saddr, ntohs(th->source),
691 				     &ip6h->daddr, ntohs(th->dest));
692 		return 1;
693 	}
694 	return 0;
695 }
696 #endif
697 
698 struct request_sock_ops tcp6_request_sock_ops __read_mostly = {
699 	.family		=	AF_INET6,
700 	.obj_size	=	sizeof(struct tcp6_request_sock),
701 	.rtx_syn_ack	=	tcp_v6_rtx_synack,
702 	.send_ack	=	tcp_v6_reqsk_send_ack,
703 	.destructor	=	tcp_v6_reqsk_destructor,
704 	.send_reset	=	tcp_v6_send_reset,
705 	.syn_ack_timeout = 	tcp_syn_ack_timeout,
706 };
707 
708 #ifdef CONFIG_TCP_MD5SIG
709 static const struct tcp_request_sock_ops tcp_request_sock_ipv6_ops = {
710 	.md5_lookup	=	tcp_v6_reqsk_md5_lookup,
711 	.calc_md5_hash	=	tcp_v6_md5_hash_skb,
712 };
713 #endif
714 
715 static void tcp_v6_send_response(struct sk_buff *skb, u32 seq, u32 ack, u32 win,
716 				 u32 ts, struct tcp_md5sig_key *key, int rst, u8 tclass)
717 {
718 	const struct tcphdr *th = tcp_hdr(skb);
719 	struct tcphdr *t1;
720 	struct sk_buff *buff;
721 	struct flowi6 fl6;
722 	struct net *net = dev_net(skb_dst(skb)->dev);
723 	struct sock *ctl_sk = net->ipv6.tcp_sk;
724 	unsigned int tot_len = sizeof(struct tcphdr);
725 	struct dst_entry *dst;
726 	__be32 *topt;
727 
728 	if (ts)
729 		tot_len += TCPOLEN_TSTAMP_ALIGNED;
730 #ifdef CONFIG_TCP_MD5SIG
731 	if (key)
732 		tot_len += TCPOLEN_MD5SIG_ALIGNED;
733 #endif
734 
735 	buff = alloc_skb(MAX_HEADER + sizeof(struct ipv6hdr) + tot_len,
736 			 GFP_ATOMIC);
737 	if (buff == NULL)
738 		return;
739 
740 	skb_reserve(buff, MAX_HEADER + sizeof(struct ipv6hdr) + tot_len);
741 
742 	t1 = (struct tcphdr *) skb_push(buff, tot_len);
743 	skb_reset_transport_header(buff);
744 
745 	/* Swap the send and the receive. */
746 	memset(t1, 0, sizeof(*t1));
747 	t1->dest = th->source;
748 	t1->source = th->dest;
749 	t1->doff = tot_len / 4;
750 	t1->seq = htonl(seq);
751 	t1->ack_seq = htonl(ack);
752 	t1->ack = !rst || !th->ack;
753 	t1->rst = rst;
754 	t1->window = htons(win);
755 
756 	topt = (__be32 *)(t1 + 1);
757 
758 	if (ts) {
759 		*topt++ = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
760 				(TCPOPT_TIMESTAMP << 8) | TCPOLEN_TIMESTAMP);
761 		*topt++ = htonl(tcp_time_stamp);
762 		*topt++ = htonl(ts);
763 	}
764 
765 #ifdef CONFIG_TCP_MD5SIG
766 	if (key) {
767 		*topt++ = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
768 				(TCPOPT_MD5SIG << 8) | TCPOLEN_MD5SIG);
769 		tcp_v6_md5_hash_hdr((__u8 *)topt, key,
770 				    &ipv6_hdr(skb)->saddr,
771 				    &ipv6_hdr(skb)->daddr, t1);
772 	}
773 #endif
774 
775 	memset(&fl6, 0, sizeof(fl6));
776 	fl6.daddr = ipv6_hdr(skb)->saddr;
777 	fl6.saddr = ipv6_hdr(skb)->daddr;
778 
779 	buff->ip_summed = CHECKSUM_PARTIAL;
780 	buff->csum = 0;
781 
782 	__tcp_v6_send_check(buff, &fl6.saddr, &fl6.daddr);
783 
784 	fl6.flowi6_proto = IPPROTO_TCP;
785 	if (ipv6_addr_type(&fl6.daddr) & IPV6_ADDR_LINKLOCAL)
786 		fl6.flowi6_oif = inet6_iif(skb);
787 	fl6.fl6_dport = t1->dest;
788 	fl6.fl6_sport = t1->source;
789 	security_skb_classify_flow(skb, flowi6_to_flowi(&fl6));
790 
791 	/* Pass a socket to ip6_dst_lookup either it is for RST
792 	 * Underlying function will use this to retrieve the network
793 	 * namespace
794 	 */
795 	dst = ip6_dst_lookup_flow(ctl_sk, &fl6, NULL, false);
796 	if (!IS_ERR(dst)) {
797 		skb_dst_set(buff, dst);
798 		ip6_xmit(ctl_sk, buff, &fl6, NULL, tclass);
799 		TCP_INC_STATS_BH(net, TCP_MIB_OUTSEGS);
800 		if (rst)
801 			TCP_INC_STATS_BH(net, TCP_MIB_OUTRSTS);
802 		return;
803 	}
804 
805 	kfree_skb(buff);
806 }
807 
808 static void tcp_v6_send_reset(struct sock *sk, struct sk_buff *skb)
809 {
810 	const struct tcphdr *th = tcp_hdr(skb);
811 	u32 seq = 0, ack_seq = 0;
812 	struct tcp_md5sig_key *key = NULL;
813 #ifdef CONFIG_TCP_MD5SIG
814 	const __u8 *hash_location = NULL;
815 	struct ipv6hdr *ipv6h = ipv6_hdr(skb);
816 	unsigned char newhash[16];
817 	int genhash;
818 	struct sock *sk1 = NULL;
819 #endif
820 
821 	if (th->rst)
822 		return;
823 
824 	if (!ipv6_unicast_destination(skb))
825 		return;
826 
827 #ifdef CONFIG_TCP_MD5SIG
828 	hash_location = tcp_parse_md5sig_option(th);
829 	if (!sk && hash_location) {
830 		/*
831 		 * active side is lost. Try to find listening socket through
832 		 * source port, and then find md5 key through listening socket.
833 		 * we are not loose security here:
834 		 * Incoming packet is checked with md5 hash with finding key,
835 		 * no RST generated if md5 hash doesn't match.
836 		 */
837 		sk1 = inet6_lookup_listener(dev_net(skb_dst(skb)->dev),
838 					   &tcp_hashinfo, &ipv6h->daddr,
839 					   ntohs(th->source), inet6_iif(skb));
840 		if (!sk1)
841 			return;
842 
843 		rcu_read_lock();
844 		key = tcp_v6_md5_do_lookup(sk1, &ipv6h->saddr);
845 		if (!key)
846 			goto release_sk1;
847 
848 		genhash = tcp_v6_md5_hash_skb(newhash, key, NULL, NULL, skb);
849 		if (genhash || memcmp(hash_location, newhash, 16) != 0)
850 			goto release_sk1;
851 	} else {
852 		key = sk ? tcp_v6_md5_do_lookup(sk, &ipv6h->saddr) : NULL;
853 	}
854 #endif
855 
856 	if (th->ack)
857 		seq = ntohl(th->ack_seq);
858 	else
859 		ack_seq = ntohl(th->seq) + th->syn + th->fin + skb->len -
860 			  (th->doff << 2);
861 
862 	tcp_v6_send_response(skb, seq, ack_seq, 0, 0, key, 1, 0);
863 
864 #ifdef CONFIG_TCP_MD5SIG
865 release_sk1:
866 	if (sk1) {
867 		rcu_read_unlock();
868 		sock_put(sk1);
869 	}
870 #endif
871 }
872 
873 static void tcp_v6_send_ack(struct sk_buff *skb, u32 seq, u32 ack, u32 win, u32 ts,
874 			    struct tcp_md5sig_key *key, u8 tclass)
875 {
876 	tcp_v6_send_response(skb, seq, ack, win, ts, key, 0, tclass);
877 }
878 
879 static void tcp_v6_timewait_ack(struct sock *sk, struct sk_buff *skb)
880 {
881 	struct inet_timewait_sock *tw = inet_twsk(sk);
882 	struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
883 
884 	tcp_v6_send_ack(skb, tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
885 			tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
886 			tcptw->tw_ts_recent, tcp_twsk_md5_key(tcptw),
887 			tw->tw_tclass);
888 
889 	inet_twsk_put(tw);
890 }
891 
892 static void tcp_v6_reqsk_send_ack(struct sock *sk, struct sk_buff *skb,
893 				  struct request_sock *req)
894 {
895 	tcp_v6_send_ack(skb, tcp_rsk(req)->snt_isn + 1, tcp_rsk(req)->rcv_isn + 1, req->rcv_wnd, req->ts_recent,
896 			tcp_v6_md5_do_lookup(sk, &ipv6_hdr(skb)->daddr), 0);
897 }
898 
899 
900 static struct sock *tcp_v6_hnd_req(struct sock *sk,struct sk_buff *skb)
901 {
902 	struct request_sock *req, **prev;
903 	const struct tcphdr *th = tcp_hdr(skb);
904 	struct sock *nsk;
905 
906 	/* Find possible connection requests. */
907 	req = inet6_csk_search_req(sk, &prev, th->source,
908 				   &ipv6_hdr(skb)->saddr,
909 				   &ipv6_hdr(skb)->daddr, inet6_iif(skb));
910 	if (req)
911 		return tcp_check_req(sk, skb, req, prev, false);
912 
913 	nsk = __inet6_lookup_established(sock_net(sk), &tcp_hashinfo,
914 			&ipv6_hdr(skb)->saddr, th->source,
915 			&ipv6_hdr(skb)->daddr, ntohs(th->dest), inet6_iif(skb));
916 
917 	if (nsk) {
918 		if (nsk->sk_state != TCP_TIME_WAIT) {
919 			bh_lock_sock(nsk);
920 			return nsk;
921 		}
922 		inet_twsk_put(inet_twsk(nsk));
923 		return NULL;
924 	}
925 
926 #ifdef CONFIG_SYN_COOKIES
927 	if (!th->syn)
928 		sk = cookie_v6_check(sk, skb);
929 #endif
930 	return sk;
931 }
932 
933 /* FIXME: this is substantially similar to the ipv4 code.
934  * Can some kind of merge be done? -- erics
935  */
936 static int tcp_v6_conn_request(struct sock *sk, struct sk_buff *skb)
937 {
938 	struct tcp_extend_values tmp_ext;
939 	struct tcp_options_received tmp_opt;
940 	const u8 *hash_location;
941 	struct request_sock *req;
942 	struct inet6_request_sock *treq;
943 	struct ipv6_pinfo *np = inet6_sk(sk);
944 	struct tcp_sock *tp = tcp_sk(sk);
945 	__u32 isn = TCP_SKB_CB(skb)->when;
946 	struct dst_entry *dst = NULL;
947 	struct flowi6 fl6;
948 	bool want_cookie = false;
949 
950 	if (skb->protocol == htons(ETH_P_IP))
951 		return tcp_v4_conn_request(sk, skb);
952 
953 	if (!ipv6_unicast_destination(skb))
954 		goto drop;
955 
956 	if (inet_csk_reqsk_queue_is_full(sk) && !isn) {
957 		want_cookie = tcp_syn_flood_action(sk, skb, "TCPv6");
958 		if (!want_cookie)
959 			goto drop;
960 	}
961 
962 	if (sk_acceptq_is_full(sk) && inet_csk_reqsk_queue_young(sk) > 1) {
963 		NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
964 		goto drop;
965 	}
966 
967 	req = inet6_reqsk_alloc(&tcp6_request_sock_ops);
968 	if (req == NULL)
969 		goto drop;
970 
971 #ifdef CONFIG_TCP_MD5SIG
972 	tcp_rsk(req)->af_specific = &tcp_request_sock_ipv6_ops;
973 #endif
974 
975 	tcp_clear_options(&tmp_opt);
976 	tmp_opt.mss_clamp = IPV6_MIN_MTU - sizeof(struct tcphdr) - sizeof(struct ipv6hdr);
977 	tmp_opt.user_mss = tp->rx_opt.user_mss;
978 	tcp_parse_options(skb, &tmp_opt, &hash_location, 0, NULL);
979 
980 	if (tmp_opt.cookie_plus > 0 &&
981 	    tmp_opt.saw_tstamp &&
982 	    !tp->rx_opt.cookie_out_never &&
983 	    (sysctl_tcp_cookie_size > 0 ||
984 	     (tp->cookie_values != NULL &&
985 	      tp->cookie_values->cookie_desired > 0))) {
986 		u8 *c;
987 		u32 *d;
988 		u32 *mess = &tmp_ext.cookie_bakery[COOKIE_DIGEST_WORDS];
989 		int l = tmp_opt.cookie_plus - TCPOLEN_COOKIE_BASE;
990 
991 		if (tcp_cookie_generator(&tmp_ext.cookie_bakery[0]) != 0)
992 			goto drop_and_free;
993 
994 		/* Secret recipe starts with IP addresses */
995 		d = (__force u32 *)&ipv6_hdr(skb)->daddr.s6_addr32[0];
996 		*mess++ ^= *d++;
997 		*mess++ ^= *d++;
998 		*mess++ ^= *d++;
999 		*mess++ ^= *d++;
1000 		d = (__force u32 *)&ipv6_hdr(skb)->saddr.s6_addr32[0];
1001 		*mess++ ^= *d++;
1002 		*mess++ ^= *d++;
1003 		*mess++ ^= *d++;
1004 		*mess++ ^= *d++;
1005 
1006 		/* plus variable length Initiator Cookie */
1007 		c = (u8 *)mess;
1008 		while (l-- > 0)
1009 			*c++ ^= *hash_location++;
1010 
1011 		want_cookie = false;	/* not our kind of cookie */
1012 		tmp_ext.cookie_out_never = 0; /* false */
1013 		tmp_ext.cookie_plus = tmp_opt.cookie_plus;
1014 	} else if (!tp->rx_opt.cookie_in_always) {
1015 		/* redundant indications, but ensure initialization. */
1016 		tmp_ext.cookie_out_never = 1; /* true */
1017 		tmp_ext.cookie_plus = 0;
1018 	} else {
1019 		goto drop_and_free;
1020 	}
1021 	tmp_ext.cookie_in_always = tp->rx_opt.cookie_in_always;
1022 
1023 	if (want_cookie && !tmp_opt.saw_tstamp)
1024 		tcp_clear_options(&tmp_opt);
1025 
1026 	tmp_opt.tstamp_ok = tmp_opt.saw_tstamp;
1027 	tcp_openreq_init(req, &tmp_opt, skb);
1028 
1029 	treq = inet6_rsk(req);
1030 	treq->rmt_addr = ipv6_hdr(skb)->saddr;
1031 	treq->loc_addr = ipv6_hdr(skb)->daddr;
1032 	if (!want_cookie || tmp_opt.tstamp_ok)
1033 		TCP_ECN_create_request(req, skb);
1034 
1035 	treq->iif = sk->sk_bound_dev_if;
1036 
1037 	/* So that link locals have meaning */
1038 	if (!sk->sk_bound_dev_if &&
1039 	    ipv6_addr_type(&treq->rmt_addr) & IPV6_ADDR_LINKLOCAL)
1040 		treq->iif = inet6_iif(skb);
1041 
1042 	if (!isn) {
1043 		if (ipv6_opt_accepted(sk, skb) ||
1044 		    np->rxopt.bits.rxinfo || np->rxopt.bits.rxoinfo ||
1045 		    np->rxopt.bits.rxhlim || np->rxopt.bits.rxohlim) {
1046 			atomic_inc(&skb->users);
1047 			treq->pktopts = skb;
1048 		}
1049 
1050 		if (want_cookie) {
1051 			isn = cookie_v6_init_sequence(sk, skb, &req->mss);
1052 			req->cookie_ts = tmp_opt.tstamp_ok;
1053 			goto have_isn;
1054 		}
1055 
1056 		/* VJ's idea. We save last timestamp seen
1057 		 * from the destination in peer table, when entering
1058 		 * state TIME-WAIT, and check against it before
1059 		 * accepting new connection request.
1060 		 *
1061 		 * If "isn" is not zero, this request hit alive
1062 		 * timewait bucket, so that all the necessary checks
1063 		 * are made in the function processing timewait state.
1064 		 */
1065 		if (tmp_opt.saw_tstamp &&
1066 		    tcp_death_row.sysctl_tw_recycle &&
1067 		    (dst = inet6_csk_route_req(sk, &fl6, req)) != NULL) {
1068 			if (!tcp_peer_is_proven(req, dst, true)) {
1069 				NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_PAWSPASSIVEREJECTED);
1070 				goto drop_and_release;
1071 			}
1072 		}
1073 		/* Kill the following clause, if you dislike this way. */
1074 		else if (!sysctl_tcp_syncookies &&
1075 			 (sysctl_max_syn_backlog - inet_csk_reqsk_queue_len(sk) <
1076 			  (sysctl_max_syn_backlog >> 2)) &&
1077 			 !tcp_peer_is_proven(req, dst, false)) {
1078 			/* Without syncookies last quarter of
1079 			 * backlog is filled with destinations,
1080 			 * proven to be alive.
1081 			 * It means that we continue to communicate
1082 			 * to destinations, already remembered
1083 			 * to the moment of synflood.
1084 			 */
1085 			LIMIT_NETDEBUG(KERN_DEBUG "TCP: drop open request from %pI6/%u\n",
1086 				       &treq->rmt_addr, ntohs(tcp_hdr(skb)->source));
1087 			goto drop_and_release;
1088 		}
1089 
1090 		isn = tcp_v6_init_sequence(skb);
1091 	}
1092 have_isn:
1093 	tcp_rsk(req)->snt_isn = isn;
1094 
1095 	if (security_inet_conn_request(sk, skb, req))
1096 		goto drop_and_release;
1097 
1098 	if (tcp_v6_send_synack(sk, dst, &fl6, req,
1099 			       (struct request_values *)&tmp_ext,
1100 			       skb_get_queue_mapping(skb)) ||
1101 	    want_cookie)
1102 		goto drop_and_free;
1103 
1104 	tcp_rsk(req)->snt_synack = tcp_time_stamp;
1105 	tcp_rsk(req)->listener = NULL;
1106 	inet6_csk_reqsk_queue_hash_add(sk, req, TCP_TIMEOUT_INIT);
1107 	return 0;
1108 
1109 drop_and_release:
1110 	dst_release(dst);
1111 drop_and_free:
1112 	reqsk_free(req);
1113 drop:
1114 	NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
1115 	return 0; /* don't send reset */
1116 }
1117 
1118 static struct sock * tcp_v6_syn_recv_sock(struct sock *sk, struct sk_buff *skb,
1119 					  struct request_sock *req,
1120 					  struct dst_entry *dst)
1121 {
1122 	struct inet6_request_sock *treq;
1123 	struct ipv6_pinfo *newnp, *np = inet6_sk(sk);
1124 	struct tcp6_sock *newtcp6sk;
1125 	struct inet_sock *newinet;
1126 	struct tcp_sock *newtp;
1127 	struct sock *newsk;
1128 #ifdef CONFIG_TCP_MD5SIG
1129 	struct tcp_md5sig_key *key;
1130 #endif
1131 	struct flowi6 fl6;
1132 
1133 	if (skb->protocol == htons(ETH_P_IP)) {
1134 		/*
1135 		 *	v6 mapped
1136 		 */
1137 
1138 		newsk = tcp_v4_syn_recv_sock(sk, skb, req, dst);
1139 
1140 		if (newsk == NULL)
1141 			return NULL;
1142 
1143 		newtcp6sk = (struct tcp6_sock *)newsk;
1144 		inet_sk(newsk)->pinet6 = &newtcp6sk->inet6;
1145 
1146 		newinet = inet_sk(newsk);
1147 		newnp = inet6_sk(newsk);
1148 		newtp = tcp_sk(newsk);
1149 
1150 		memcpy(newnp, np, sizeof(struct ipv6_pinfo));
1151 
1152 		ipv6_addr_set_v4mapped(newinet->inet_daddr, &newnp->daddr);
1153 
1154 		ipv6_addr_set_v4mapped(newinet->inet_saddr, &newnp->saddr);
1155 
1156 		newnp->rcv_saddr = newnp->saddr;
1157 
1158 		inet_csk(newsk)->icsk_af_ops = &ipv6_mapped;
1159 		newsk->sk_backlog_rcv = tcp_v4_do_rcv;
1160 #ifdef CONFIG_TCP_MD5SIG
1161 		newtp->af_specific = &tcp_sock_ipv6_mapped_specific;
1162 #endif
1163 
1164 		newnp->ipv6_ac_list = NULL;
1165 		newnp->ipv6_fl_list = NULL;
1166 		newnp->pktoptions  = NULL;
1167 		newnp->opt	   = NULL;
1168 		newnp->mcast_oif   = inet6_iif(skb);
1169 		newnp->mcast_hops  = ipv6_hdr(skb)->hop_limit;
1170 		newnp->rcv_tclass  = ipv6_tclass(ipv6_hdr(skb));
1171 
1172 		/*
1173 		 * No need to charge this sock to the relevant IPv6 refcnt debug socks count
1174 		 * here, tcp_create_openreq_child now does this for us, see the comment in
1175 		 * that function for the gory details. -acme
1176 		 */
1177 
1178 		/* It is tricky place. Until this moment IPv4 tcp
1179 		   worked with IPv6 icsk.icsk_af_ops.
1180 		   Sync it now.
1181 		 */
1182 		tcp_sync_mss(newsk, inet_csk(newsk)->icsk_pmtu_cookie);
1183 
1184 		return newsk;
1185 	}
1186 
1187 	treq = inet6_rsk(req);
1188 
1189 	if (sk_acceptq_is_full(sk))
1190 		goto out_overflow;
1191 
1192 	if (!dst) {
1193 		dst = inet6_csk_route_req(sk, &fl6, req);
1194 		if (!dst)
1195 			goto out;
1196 	}
1197 
1198 	newsk = tcp_create_openreq_child(sk, req, skb);
1199 	if (newsk == NULL)
1200 		goto out_nonewsk;
1201 
1202 	/*
1203 	 * No need to charge this sock to the relevant IPv6 refcnt debug socks
1204 	 * count here, tcp_create_openreq_child now does this for us, see the
1205 	 * comment in that function for the gory details. -acme
1206 	 */
1207 
1208 	newsk->sk_gso_type = SKB_GSO_TCPV6;
1209 	__ip6_dst_store(newsk, dst, NULL, NULL);
1210 	inet6_sk_rx_dst_set(newsk, skb);
1211 
1212 	newtcp6sk = (struct tcp6_sock *)newsk;
1213 	inet_sk(newsk)->pinet6 = &newtcp6sk->inet6;
1214 
1215 	newtp = tcp_sk(newsk);
1216 	newinet = inet_sk(newsk);
1217 	newnp = inet6_sk(newsk);
1218 
1219 	memcpy(newnp, np, sizeof(struct ipv6_pinfo));
1220 
1221 	newnp->daddr = treq->rmt_addr;
1222 	newnp->saddr = treq->loc_addr;
1223 	newnp->rcv_saddr = treq->loc_addr;
1224 	newsk->sk_bound_dev_if = treq->iif;
1225 
1226 	/* Now IPv6 options...
1227 
1228 	   First: no IPv4 options.
1229 	 */
1230 	newinet->inet_opt = NULL;
1231 	newnp->ipv6_ac_list = NULL;
1232 	newnp->ipv6_fl_list = NULL;
1233 
1234 	/* Clone RX bits */
1235 	newnp->rxopt.all = np->rxopt.all;
1236 
1237 	/* Clone pktoptions received with SYN */
1238 	newnp->pktoptions = NULL;
1239 	if (treq->pktopts != NULL) {
1240 		newnp->pktoptions = skb_clone(treq->pktopts,
1241 					      sk_gfp_atomic(sk, GFP_ATOMIC));
1242 		consume_skb(treq->pktopts);
1243 		treq->pktopts = NULL;
1244 		if (newnp->pktoptions)
1245 			skb_set_owner_r(newnp->pktoptions, newsk);
1246 	}
1247 	newnp->opt	  = NULL;
1248 	newnp->mcast_oif  = inet6_iif(skb);
1249 	newnp->mcast_hops = ipv6_hdr(skb)->hop_limit;
1250 	newnp->rcv_tclass = ipv6_tclass(ipv6_hdr(skb));
1251 
1252 	/* Clone native IPv6 options from listening socket (if any)
1253 
1254 	   Yes, keeping reference count would be much more clever,
1255 	   but we make one more one thing there: reattach optmem
1256 	   to newsk.
1257 	 */
1258 	if (np->opt)
1259 		newnp->opt = ipv6_dup_options(newsk, np->opt);
1260 
1261 	inet_csk(newsk)->icsk_ext_hdr_len = 0;
1262 	if (newnp->opt)
1263 		inet_csk(newsk)->icsk_ext_hdr_len = (newnp->opt->opt_nflen +
1264 						     newnp->opt->opt_flen);
1265 
1266 	tcp_mtup_init(newsk);
1267 	tcp_sync_mss(newsk, dst_mtu(dst));
1268 	newtp->advmss = dst_metric_advmss(dst);
1269 	if (tcp_sk(sk)->rx_opt.user_mss &&
1270 	    tcp_sk(sk)->rx_opt.user_mss < newtp->advmss)
1271 		newtp->advmss = tcp_sk(sk)->rx_opt.user_mss;
1272 
1273 	tcp_initialize_rcv_mss(newsk);
1274 	tcp_synack_rtt_meas(newsk, req);
1275 	newtp->total_retrans = req->num_retrans;
1276 
1277 	newinet->inet_daddr = newinet->inet_saddr = LOOPBACK4_IPV6;
1278 	newinet->inet_rcv_saddr = LOOPBACK4_IPV6;
1279 
1280 #ifdef CONFIG_TCP_MD5SIG
1281 	/* Copy over the MD5 key from the original socket */
1282 	if ((key = tcp_v6_md5_do_lookup(sk, &newnp->daddr)) != NULL) {
1283 		/* We're using one, so create a matching key
1284 		 * on the newsk structure. If we fail to get
1285 		 * memory, then we end up not copying the key
1286 		 * across. Shucks.
1287 		 */
1288 		tcp_md5_do_add(newsk, (union tcp_md5_addr *)&newnp->daddr,
1289 			       AF_INET6, key->key, key->keylen,
1290 			       sk_gfp_atomic(sk, GFP_ATOMIC));
1291 	}
1292 #endif
1293 
1294 	if (__inet_inherit_port(sk, newsk) < 0) {
1295 		inet_csk_prepare_forced_close(newsk);
1296 		tcp_done(newsk);
1297 		goto out;
1298 	}
1299 	__inet6_hash(newsk, NULL);
1300 
1301 	return newsk;
1302 
1303 out_overflow:
1304 	NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
1305 out_nonewsk:
1306 	dst_release(dst);
1307 out:
1308 	NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
1309 	return NULL;
1310 }
1311 
1312 static __sum16 tcp_v6_checksum_init(struct sk_buff *skb)
1313 {
1314 	if (skb->ip_summed == CHECKSUM_COMPLETE) {
1315 		if (!tcp_v6_check(skb->len, &ipv6_hdr(skb)->saddr,
1316 				  &ipv6_hdr(skb)->daddr, skb->csum)) {
1317 			skb->ip_summed = CHECKSUM_UNNECESSARY;
1318 			return 0;
1319 		}
1320 	}
1321 
1322 	skb->csum = ~csum_unfold(tcp_v6_check(skb->len,
1323 					      &ipv6_hdr(skb)->saddr,
1324 					      &ipv6_hdr(skb)->daddr, 0));
1325 
1326 	if (skb->len <= 76) {
1327 		return __skb_checksum_complete(skb);
1328 	}
1329 	return 0;
1330 }
1331 
1332 /* The socket must have it's spinlock held when we get
1333  * here.
1334  *
1335  * We have a potential double-lock case here, so even when
1336  * doing backlog processing we use the BH locking scheme.
1337  * This is because we cannot sleep with the original spinlock
1338  * held.
1339  */
1340 static int tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb)
1341 {
1342 	struct ipv6_pinfo *np = inet6_sk(sk);
1343 	struct tcp_sock *tp;
1344 	struct sk_buff *opt_skb = NULL;
1345 
1346 	/* Imagine: socket is IPv6. IPv4 packet arrives,
1347 	   goes to IPv4 receive handler and backlogged.
1348 	   From backlog it always goes here. Kerboom...
1349 	   Fortunately, tcp_rcv_established and rcv_established
1350 	   handle them correctly, but it is not case with
1351 	   tcp_v6_hnd_req and tcp_v6_send_reset().   --ANK
1352 	 */
1353 
1354 	if (skb->protocol == htons(ETH_P_IP))
1355 		return tcp_v4_do_rcv(sk, skb);
1356 
1357 #ifdef CONFIG_TCP_MD5SIG
1358 	if (tcp_v6_inbound_md5_hash (sk, skb))
1359 		goto discard;
1360 #endif
1361 
1362 	if (sk_filter(sk, skb))
1363 		goto discard;
1364 
1365 	/*
1366 	 *	socket locking is here for SMP purposes as backlog rcv
1367 	 *	is currently called with bh processing disabled.
1368 	 */
1369 
1370 	/* Do Stevens' IPV6_PKTOPTIONS.
1371 
1372 	   Yes, guys, it is the only place in our code, where we
1373 	   may make it not affecting IPv4.
1374 	   The rest of code is protocol independent,
1375 	   and I do not like idea to uglify IPv4.
1376 
1377 	   Actually, all the idea behind IPV6_PKTOPTIONS
1378 	   looks not very well thought. For now we latch
1379 	   options, received in the last packet, enqueued
1380 	   by tcp. Feel free to propose better solution.
1381 					       --ANK (980728)
1382 	 */
1383 	if (np->rxopt.all)
1384 		opt_skb = skb_clone(skb, sk_gfp_atomic(sk, GFP_ATOMIC));
1385 
1386 	if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
1387 		struct dst_entry *dst = sk->sk_rx_dst;
1388 
1389 		sock_rps_save_rxhash(sk, skb);
1390 		if (dst) {
1391 			if (inet_sk(sk)->rx_dst_ifindex != skb->skb_iif ||
1392 			    dst->ops->check(dst, np->rx_dst_cookie) == NULL) {
1393 				dst_release(dst);
1394 				sk->sk_rx_dst = NULL;
1395 			}
1396 		}
1397 
1398 		if (tcp_rcv_established(sk, skb, tcp_hdr(skb), skb->len))
1399 			goto reset;
1400 		if (opt_skb)
1401 			goto ipv6_pktoptions;
1402 		return 0;
1403 	}
1404 
1405 	if (skb->len < tcp_hdrlen(skb) || tcp_checksum_complete(skb))
1406 		goto csum_err;
1407 
1408 	if (sk->sk_state == TCP_LISTEN) {
1409 		struct sock *nsk = tcp_v6_hnd_req(sk, skb);
1410 		if (!nsk)
1411 			goto discard;
1412 
1413 		/*
1414 		 * Queue it on the new socket if the new socket is active,
1415 		 * otherwise we just shortcircuit this and continue with
1416 		 * the new socket..
1417 		 */
1418 		if(nsk != sk) {
1419 			sock_rps_save_rxhash(nsk, skb);
1420 			if (tcp_child_process(sk, nsk, skb))
1421 				goto reset;
1422 			if (opt_skb)
1423 				__kfree_skb(opt_skb);
1424 			return 0;
1425 		}
1426 	} else
1427 		sock_rps_save_rxhash(sk, skb);
1428 
1429 	if (tcp_rcv_state_process(sk, skb, tcp_hdr(skb), skb->len))
1430 		goto reset;
1431 	if (opt_skb)
1432 		goto ipv6_pktoptions;
1433 	return 0;
1434 
1435 reset:
1436 	tcp_v6_send_reset(sk, skb);
1437 discard:
1438 	if (opt_skb)
1439 		__kfree_skb(opt_skb);
1440 	kfree_skb(skb);
1441 	return 0;
1442 csum_err:
1443 	TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_INERRS);
1444 	goto discard;
1445 
1446 
1447 ipv6_pktoptions:
1448 	/* Do you ask, what is it?
1449 
1450 	   1. skb was enqueued by tcp.
1451 	   2. skb is added to tail of read queue, rather than out of order.
1452 	   3. socket is not in passive state.
1453 	   4. Finally, it really contains options, which user wants to receive.
1454 	 */
1455 	tp = tcp_sk(sk);
1456 	if (TCP_SKB_CB(opt_skb)->end_seq == tp->rcv_nxt &&
1457 	    !((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN))) {
1458 		if (np->rxopt.bits.rxinfo || np->rxopt.bits.rxoinfo)
1459 			np->mcast_oif = inet6_iif(opt_skb);
1460 		if (np->rxopt.bits.rxhlim || np->rxopt.bits.rxohlim)
1461 			np->mcast_hops = ipv6_hdr(opt_skb)->hop_limit;
1462 		if (np->rxopt.bits.rxtclass)
1463 			np->rcv_tclass = ipv6_tclass(ipv6_hdr(skb));
1464 		if (ipv6_opt_accepted(sk, opt_skb)) {
1465 			skb_set_owner_r(opt_skb, sk);
1466 			opt_skb = xchg(&np->pktoptions, opt_skb);
1467 		} else {
1468 			__kfree_skb(opt_skb);
1469 			opt_skb = xchg(&np->pktoptions, NULL);
1470 		}
1471 	}
1472 
1473 	kfree_skb(opt_skb);
1474 	return 0;
1475 }
1476 
1477 static int tcp_v6_rcv(struct sk_buff *skb)
1478 {
1479 	const struct tcphdr *th;
1480 	const struct ipv6hdr *hdr;
1481 	struct sock *sk;
1482 	int ret;
1483 	struct net *net = dev_net(skb->dev);
1484 
1485 	if (skb->pkt_type != PACKET_HOST)
1486 		goto discard_it;
1487 
1488 	/*
1489 	 *	Count it even if it's bad.
1490 	 */
1491 	TCP_INC_STATS_BH(net, TCP_MIB_INSEGS);
1492 
1493 	if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
1494 		goto discard_it;
1495 
1496 	th = tcp_hdr(skb);
1497 
1498 	if (th->doff < sizeof(struct tcphdr)/4)
1499 		goto bad_packet;
1500 	if (!pskb_may_pull(skb, th->doff*4))
1501 		goto discard_it;
1502 
1503 	if (!skb_csum_unnecessary(skb) && tcp_v6_checksum_init(skb))
1504 		goto bad_packet;
1505 
1506 	th = tcp_hdr(skb);
1507 	hdr = ipv6_hdr(skb);
1508 	TCP_SKB_CB(skb)->seq = ntohl(th->seq);
1509 	TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
1510 				    skb->len - th->doff*4);
1511 	TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
1512 	TCP_SKB_CB(skb)->when = 0;
1513 	TCP_SKB_CB(skb)->ip_dsfield = ipv6_get_dsfield(hdr);
1514 	TCP_SKB_CB(skb)->sacked = 0;
1515 
1516 	sk = __inet6_lookup_skb(&tcp_hashinfo, skb, th->source, th->dest);
1517 	if (!sk)
1518 		goto no_tcp_socket;
1519 
1520 process:
1521 	if (sk->sk_state == TCP_TIME_WAIT)
1522 		goto do_time_wait;
1523 
1524 	if (hdr->hop_limit < inet6_sk(sk)->min_hopcount) {
1525 		NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP);
1526 		goto discard_and_relse;
1527 	}
1528 
1529 	if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb))
1530 		goto discard_and_relse;
1531 
1532 	if (sk_filter(sk, skb))
1533 		goto discard_and_relse;
1534 
1535 	skb->dev = NULL;
1536 
1537 	bh_lock_sock_nested(sk);
1538 	ret = 0;
1539 	if (!sock_owned_by_user(sk)) {
1540 #ifdef CONFIG_NET_DMA
1541 		struct tcp_sock *tp = tcp_sk(sk);
1542 		if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list)
1543 			tp->ucopy.dma_chan = net_dma_find_channel();
1544 		if (tp->ucopy.dma_chan)
1545 			ret = tcp_v6_do_rcv(sk, skb);
1546 		else
1547 #endif
1548 		{
1549 			if (!tcp_prequeue(sk, skb))
1550 				ret = tcp_v6_do_rcv(sk, skb);
1551 		}
1552 	} else if (unlikely(sk_add_backlog(sk, skb,
1553 					   sk->sk_rcvbuf + sk->sk_sndbuf))) {
1554 		bh_unlock_sock(sk);
1555 		NET_INC_STATS_BH(net, LINUX_MIB_TCPBACKLOGDROP);
1556 		goto discard_and_relse;
1557 	}
1558 	bh_unlock_sock(sk);
1559 
1560 	sock_put(sk);
1561 	return ret ? -1 : 0;
1562 
1563 no_tcp_socket:
1564 	if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb))
1565 		goto discard_it;
1566 
1567 	if (skb->len < (th->doff<<2) || tcp_checksum_complete(skb)) {
1568 bad_packet:
1569 		TCP_INC_STATS_BH(net, TCP_MIB_INERRS);
1570 	} else {
1571 		tcp_v6_send_reset(NULL, skb);
1572 	}
1573 
1574 discard_it:
1575 
1576 	/*
1577 	 *	Discard frame
1578 	 */
1579 
1580 	kfree_skb(skb);
1581 	return 0;
1582 
1583 discard_and_relse:
1584 	sock_put(sk);
1585 	goto discard_it;
1586 
1587 do_time_wait:
1588 	if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
1589 		inet_twsk_put(inet_twsk(sk));
1590 		goto discard_it;
1591 	}
1592 
1593 	if (skb->len < (th->doff<<2) || tcp_checksum_complete(skb)) {
1594 		TCP_INC_STATS_BH(net, TCP_MIB_INERRS);
1595 		inet_twsk_put(inet_twsk(sk));
1596 		goto discard_it;
1597 	}
1598 
1599 	switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) {
1600 	case TCP_TW_SYN:
1601 	{
1602 		struct sock *sk2;
1603 
1604 		sk2 = inet6_lookup_listener(dev_net(skb->dev), &tcp_hashinfo,
1605 					    &ipv6_hdr(skb)->daddr,
1606 					    ntohs(th->dest), inet6_iif(skb));
1607 		if (sk2 != NULL) {
1608 			struct inet_timewait_sock *tw = inet_twsk(sk);
1609 			inet_twsk_deschedule(tw, &tcp_death_row);
1610 			inet_twsk_put(tw);
1611 			sk = sk2;
1612 			goto process;
1613 		}
1614 		/* Fall through to ACK */
1615 	}
1616 	case TCP_TW_ACK:
1617 		tcp_v6_timewait_ack(sk, skb);
1618 		break;
1619 	case TCP_TW_RST:
1620 		goto no_tcp_socket;
1621 	case TCP_TW_SUCCESS:;
1622 	}
1623 	goto discard_it;
1624 }
1625 
1626 static void tcp_v6_early_demux(struct sk_buff *skb)
1627 {
1628 	const struct ipv6hdr *hdr;
1629 	const struct tcphdr *th;
1630 	struct sock *sk;
1631 
1632 	if (skb->pkt_type != PACKET_HOST)
1633 		return;
1634 
1635 	if (!pskb_may_pull(skb, skb_transport_offset(skb) + sizeof(struct tcphdr)))
1636 		return;
1637 
1638 	hdr = ipv6_hdr(skb);
1639 	th = tcp_hdr(skb);
1640 
1641 	if (th->doff < sizeof(struct tcphdr) / 4)
1642 		return;
1643 
1644 	sk = __inet6_lookup_established(dev_net(skb->dev), &tcp_hashinfo,
1645 					&hdr->saddr, th->source,
1646 					&hdr->daddr, ntohs(th->dest),
1647 					inet6_iif(skb));
1648 	if (sk) {
1649 		skb->sk = sk;
1650 		skb->destructor = sock_edemux;
1651 		if (sk->sk_state != TCP_TIME_WAIT) {
1652 			struct dst_entry *dst = sk->sk_rx_dst;
1653 
1654 			if (dst)
1655 				dst = dst_check(dst, inet6_sk(sk)->rx_dst_cookie);
1656 			if (dst &&
1657 			    inet_sk(sk)->rx_dst_ifindex == skb->skb_iif)
1658 				skb_dst_set_noref(skb, dst);
1659 		}
1660 	}
1661 }
1662 
1663 static struct timewait_sock_ops tcp6_timewait_sock_ops = {
1664 	.twsk_obj_size	= sizeof(struct tcp6_timewait_sock),
1665 	.twsk_unique	= tcp_twsk_unique,
1666 	.twsk_destructor= tcp_twsk_destructor,
1667 };
1668 
1669 static const struct inet_connection_sock_af_ops ipv6_specific = {
1670 	.queue_xmit	   = inet6_csk_xmit,
1671 	.send_check	   = tcp_v6_send_check,
1672 	.rebuild_header	   = inet6_sk_rebuild_header,
1673 	.sk_rx_dst_set	   = inet6_sk_rx_dst_set,
1674 	.conn_request	   = tcp_v6_conn_request,
1675 	.syn_recv_sock	   = tcp_v6_syn_recv_sock,
1676 	.net_header_len	   = sizeof(struct ipv6hdr),
1677 	.net_frag_header_len = sizeof(struct frag_hdr),
1678 	.setsockopt	   = ipv6_setsockopt,
1679 	.getsockopt	   = ipv6_getsockopt,
1680 	.addr2sockaddr	   = inet6_csk_addr2sockaddr,
1681 	.sockaddr_len	   = sizeof(struct sockaddr_in6),
1682 	.bind_conflict	   = inet6_csk_bind_conflict,
1683 #ifdef CONFIG_COMPAT
1684 	.compat_setsockopt = compat_ipv6_setsockopt,
1685 	.compat_getsockopt = compat_ipv6_getsockopt,
1686 #endif
1687 };
1688 
1689 #ifdef CONFIG_TCP_MD5SIG
1690 static const struct tcp_sock_af_ops tcp_sock_ipv6_specific = {
1691 	.md5_lookup	=	tcp_v6_md5_lookup,
1692 	.calc_md5_hash	=	tcp_v6_md5_hash_skb,
1693 	.md5_parse	=	tcp_v6_parse_md5_keys,
1694 };
1695 #endif
1696 
1697 /*
1698  *	TCP over IPv4 via INET6 API
1699  */
1700 
1701 static const struct inet_connection_sock_af_ops ipv6_mapped = {
1702 	.queue_xmit	   = ip_queue_xmit,
1703 	.send_check	   = tcp_v4_send_check,
1704 	.rebuild_header	   = inet_sk_rebuild_header,
1705 	.sk_rx_dst_set	   = inet_sk_rx_dst_set,
1706 	.conn_request	   = tcp_v6_conn_request,
1707 	.syn_recv_sock	   = tcp_v6_syn_recv_sock,
1708 	.net_header_len	   = sizeof(struct iphdr),
1709 	.setsockopt	   = ipv6_setsockopt,
1710 	.getsockopt	   = ipv6_getsockopt,
1711 	.addr2sockaddr	   = inet6_csk_addr2sockaddr,
1712 	.sockaddr_len	   = sizeof(struct sockaddr_in6),
1713 	.bind_conflict	   = inet6_csk_bind_conflict,
1714 #ifdef CONFIG_COMPAT
1715 	.compat_setsockopt = compat_ipv6_setsockopt,
1716 	.compat_getsockopt = compat_ipv6_getsockopt,
1717 #endif
1718 };
1719 
1720 #ifdef CONFIG_TCP_MD5SIG
1721 static const struct tcp_sock_af_ops tcp_sock_ipv6_mapped_specific = {
1722 	.md5_lookup	=	tcp_v4_md5_lookup,
1723 	.calc_md5_hash	=	tcp_v4_md5_hash_skb,
1724 	.md5_parse	=	tcp_v6_parse_md5_keys,
1725 };
1726 #endif
1727 
1728 /* NOTE: A lot of things set to zero explicitly by call to
1729  *       sk_alloc() so need not be done here.
1730  */
1731 static int tcp_v6_init_sock(struct sock *sk)
1732 {
1733 	struct inet_connection_sock *icsk = inet_csk(sk);
1734 
1735 	tcp_init_sock(sk);
1736 
1737 	icsk->icsk_af_ops = &ipv6_specific;
1738 
1739 #ifdef CONFIG_TCP_MD5SIG
1740 	tcp_sk(sk)->af_specific = &tcp_sock_ipv6_specific;
1741 #endif
1742 
1743 	return 0;
1744 }
1745 
1746 static void tcp_v6_destroy_sock(struct sock *sk)
1747 {
1748 	tcp_v4_destroy_sock(sk);
1749 	inet6_destroy_sock(sk);
1750 }
1751 
1752 #ifdef CONFIG_PROC_FS
1753 /* Proc filesystem TCPv6 sock list dumping. */
1754 static void get_openreq6(struct seq_file *seq,
1755 			 const struct sock *sk, struct request_sock *req, int i, kuid_t uid)
1756 {
1757 	int ttd = req->expires - jiffies;
1758 	const struct in6_addr *src = &inet6_rsk(req)->loc_addr;
1759 	const struct in6_addr *dest = &inet6_rsk(req)->rmt_addr;
1760 
1761 	if (ttd < 0)
1762 		ttd = 0;
1763 
1764 	seq_printf(seq,
1765 		   "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
1766 		   "%02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK\n",
1767 		   i,
1768 		   src->s6_addr32[0], src->s6_addr32[1],
1769 		   src->s6_addr32[2], src->s6_addr32[3],
1770 		   ntohs(inet_rsk(req)->loc_port),
1771 		   dest->s6_addr32[0], dest->s6_addr32[1],
1772 		   dest->s6_addr32[2], dest->s6_addr32[3],
1773 		   ntohs(inet_rsk(req)->rmt_port),
1774 		   TCP_SYN_RECV,
1775 		   0,0, /* could print option size, but that is af dependent. */
1776 		   1,   /* timers active (only the expire timer) */
1777 		   jiffies_to_clock_t(ttd),
1778 		   req->num_timeout,
1779 		   from_kuid_munged(seq_user_ns(seq), uid),
1780 		   0,  /* non standard timer */
1781 		   0, /* open_requests have no inode */
1782 		   0, req);
1783 }
1784 
1785 static void get_tcp6_sock(struct seq_file *seq, struct sock *sp, int i)
1786 {
1787 	const struct in6_addr *dest, *src;
1788 	__u16 destp, srcp;
1789 	int timer_active;
1790 	unsigned long timer_expires;
1791 	const struct inet_sock *inet = inet_sk(sp);
1792 	const struct tcp_sock *tp = tcp_sk(sp);
1793 	const struct inet_connection_sock *icsk = inet_csk(sp);
1794 	const struct ipv6_pinfo *np = inet6_sk(sp);
1795 
1796 	dest  = &np->daddr;
1797 	src   = &np->rcv_saddr;
1798 	destp = ntohs(inet->inet_dport);
1799 	srcp  = ntohs(inet->inet_sport);
1800 
1801 	if (icsk->icsk_pending == ICSK_TIME_RETRANS) {
1802 		timer_active	= 1;
1803 		timer_expires	= icsk->icsk_timeout;
1804 	} else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
1805 		timer_active	= 4;
1806 		timer_expires	= icsk->icsk_timeout;
1807 	} else if (timer_pending(&sp->sk_timer)) {
1808 		timer_active	= 2;
1809 		timer_expires	= sp->sk_timer.expires;
1810 	} else {
1811 		timer_active	= 0;
1812 		timer_expires = jiffies;
1813 	}
1814 
1815 	seq_printf(seq,
1816 		   "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
1817 		   "%02X %08X:%08X %02X:%08lX %08X %5d %8d %lu %d %pK %lu %lu %u %u %d\n",
1818 		   i,
1819 		   src->s6_addr32[0], src->s6_addr32[1],
1820 		   src->s6_addr32[2], src->s6_addr32[3], srcp,
1821 		   dest->s6_addr32[0], dest->s6_addr32[1],
1822 		   dest->s6_addr32[2], dest->s6_addr32[3], destp,
1823 		   sp->sk_state,
1824 		   tp->write_seq-tp->snd_una,
1825 		   (sp->sk_state == TCP_LISTEN) ? sp->sk_ack_backlog : (tp->rcv_nxt - tp->copied_seq),
1826 		   timer_active,
1827 		   jiffies_delta_to_clock_t(timer_expires - jiffies),
1828 		   icsk->icsk_retransmits,
1829 		   from_kuid_munged(seq_user_ns(seq), sock_i_uid(sp)),
1830 		   icsk->icsk_probes_out,
1831 		   sock_i_ino(sp),
1832 		   atomic_read(&sp->sk_refcnt), sp,
1833 		   jiffies_to_clock_t(icsk->icsk_rto),
1834 		   jiffies_to_clock_t(icsk->icsk_ack.ato),
1835 		   (icsk->icsk_ack.quick << 1 ) | icsk->icsk_ack.pingpong,
1836 		   tp->snd_cwnd,
1837 		   tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh
1838 		   );
1839 }
1840 
1841 static void get_timewait6_sock(struct seq_file *seq,
1842 			       struct inet_timewait_sock *tw, int i)
1843 {
1844 	const struct in6_addr *dest, *src;
1845 	__u16 destp, srcp;
1846 	const struct inet6_timewait_sock *tw6 = inet6_twsk((struct sock *)tw);
1847 	long delta = tw->tw_ttd - jiffies;
1848 
1849 	dest = &tw6->tw_v6_daddr;
1850 	src  = &tw6->tw_v6_rcv_saddr;
1851 	destp = ntohs(tw->tw_dport);
1852 	srcp  = ntohs(tw->tw_sport);
1853 
1854 	seq_printf(seq,
1855 		   "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
1856 		   "%02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK\n",
1857 		   i,
1858 		   src->s6_addr32[0], src->s6_addr32[1],
1859 		   src->s6_addr32[2], src->s6_addr32[3], srcp,
1860 		   dest->s6_addr32[0], dest->s6_addr32[1],
1861 		   dest->s6_addr32[2], dest->s6_addr32[3], destp,
1862 		   tw->tw_substate, 0, 0,
1863 		   3, jiffies_delta_to_clock_t(delta), 0, 0, 0, 0,
1864 		   atomic_read(&tw->tw_refcnt), tw);
1865 }
1866 
1867 static int tcp6_seq_show(struct seq_file *seq, void *v)
1868 {
1869 	struct tcp_iter_state *st;
1870 
1871 	if (v == SEQ_START_TOKEN) {
1872 		seq_puts(seq,
1873 			 "  sl  "
1874 			 "local_address                         "
1875 			 "remote_address                        "
1876 			 "st tx_queue rx_queue tr tm->when retrnsmt"
1877 			 "   uid  timeout inode\n");
1878 		goto out;
1879 	}
1880 	st = seq->private;
1881 
1882 	switch (st->state) {
1883 	case TCP_SEQ_STATE_LISTENING:
1884 	case TCP_SEQ_STATE_ESTABLISHED:
1885 		get_tcp6_sock(seq, v, st->num);
1886 		break;
1887 	case TCP_SEQ_STATE_OPENREQ:
1888 		get_openreq6(seq, st->syn_wait_sk, v, st->num, st->uid);
1889 		break;
1890 	case TCP_SEQ_STATE_TIME_WAIT:
1891 		get_timewait6_sock(seq, v, st->num);
1892 		break;
1893 	}
1894 out:
1895 	return 0;
1896 }
1897 
1898 static const struct file_operations tcp6_afinfo_seq_fops = {
1899 	.owner   = THIS_MODULE,
1900 	.open    = tcp_seq_open,
1901 	.read    = seq_read,
1902 	.llseek  = seq_lseek,
1903 	.release = seq_release_net
1904 };
1905 
1906 static struct tcp_seq_afinfo tcp6_seq_afinfo = {
1907 	.name		= "tcp6",
1908 	.family		= AF_INET6,
1909 	.seq_fops	= &tcp6_afinfo_seq_fops,
1910 	.seq_ops	= {
1911 		.show		= tcp6_seq_show,
1912 	},
1913 };
1914 
1915 int __net_init tcp6_proc_init(struct net *net)
1916 {
1917 	return tcp_proc_register(net, &tcp6_seq_afinfo);
1918 }
1919 
1920 void tcp6_proc_exit(struct net *net)
1921 {
1922 	tcp_proc_unregister(net, &tcp6_seq_afinfo);
1923 }
1924 #endif
1925 
1926 struct proto tcpv6_prot = {
1927 	.name			= "TCPv6",
1928 	.owner			= THIS_MODULE,
1929 	.close			= tcp_close,
1930 	.connect		= tcp_v6_connect,
1931 	.disconnect		= tcp_disconnect,
1932 	.accept			= inet_csk_accept,
1933 	.ioctl			= tcp_ioctl,
1934 	.init			= tcp_v6_init_sock,
1935 	.destroy		= tcp_v6_destroy_sock,
1936 	.shutdown		= tcp_shutdown,
1937 	.setsockopt		= tcp_setsockopt,
1938 	.getsockopt		= tcp_getsockopt,
1939 	.recvmsg		= tcp_recvmsg,
1940 	.sendmsg		= tcp_sendmsg,
1941 	.sendpage		= tcp_sendpage,
1942 	.backlog_rcv		= tcp_v6_do_rcv,
1943 	.release_cb		= tcp_release_cb,
1944 	.mtu_reduced		= tcp_v6_mtu_reduced,
1945 	.hash			= tcp_v6_hash,
1946 	.unhash			= inet_unhash,
1947 	.get_port		= inet_csk_get_port,
1948 	.enter_memory_pressure	= tcp_enter_memory_pressure,
1949 	.sockets_allocated	= &tcp_sockets_allocated,
1950 	.memory_allocated	= &tcp_memory_allocated,
1951 	.memory_pressure	= &tcp_memory_pressure,
1952 	.orphan_count		= &tcp_orphan_count,
1953 	.sysctl_wmem		= sysctl_tcp_wmem,
1954 	.sysctl_rmem		= sysctl_tcp_rmem,
1955 	.max_header		= MAX_TCP_HEADER,
1956 	.obj_size		= sizeof(struct tcp6_sock),
1957 	.slab_flags		= SLAB_DESTROY_BY_RCU,
1958 	.twsk_prot		= &tcp6_timewait_sock_ops,
1959 	.rsk_prot		= &tcp6_request_sock_ops,
1960 	.h.hashinfo		= &tcp_hashinfo,
1961 	.no_autobind		= true,
1962 #ifdef CONFIG_COMPAT
1963 	.compat_setsockopt	= compat_tcp_setsockopt,
1964 	.compat_getsockopt	= compat_tcp_getsockopt,
1965 #endif
1966 #ifdef CONFIG_MEMCG_KMEM
1967 	.proto_cgroup		= tcp_proto_cgroup,
1968 #endif
1969 };
1970 
1971 static const struct inet6_protocol tcpv6_protocol = {
1972 	.early_demux	=	tcp_v6_early_demux,
1973 	.handler	=	tcp_v6_rcv,
1974 	.err_handler	=	tcp_v6_err,
1975 	.flags		=	INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
1976 };
1977 
1978 static struct inet_protosw tcpv6_protosw = {
1979 	.type		=	SOCK_STREAM,
1980 	.protocol	=	IPPROTO_TCP,
1981 	.prot		=	&tcpv6_prot,
1982 	.ops		=	&inet6_stream_ops,
1983 	.no_check	=	0,
1984 	.flags		=	INET_PROTOSW_PERMANENT |
1985 				INET_PROTOSW_ICSK,
1986 };
1987 
1988 static int __net_init tcpv6_net_init(struct net *net)
1989 {
1990 	return inet_ctl_sock_create(&net->ipv6.tcp_sk, PF_INET6,
1991 				    SOCK_RAW, IPPROTO_TCP, net);
1992 }
1993 
1994 static void __net_exit tcpv6_net_exit(struct net *net)
1995 {
1996 	inet_ctl_sock_destroy(net->ipv6.tcp_sk);
1997 }
1998 
1999 static void __net_exit tcpv6_net_exit_batch(struct list_head *net_exit_list)
2000 {
2001 	inet_twsk_purge(&tcp_hashinfo, &tcp_death_row, AF_INET6);
2002 }
2003 
2004 static struct pernet_operations tcpv6_net_ops = {
2005 	.init	    = tcpv6_net_init,
2006 	.exit	    = tcpv6_net_exit,
2007 	.exit_batch = tcpv6_net_exit_batch,
2008 };
2009 
2010 int __init tcpv6_init(void)
2011 {
2012 	int ret;
2013 
2014 	ret = inet6_add_protocol(&tcpv6_protocol, IPPROTO_TCP);
2015 	if (ret)
2016 		goto out;
2017 
2018 	/* register inet6 protocol */
2019 	ret = inet6_register_protosw(&tcpv6_protosw);
2020 	if (ret)
2021 		goto out_tcpv6_protocol;
2022 
2023 	ret = register_pernet_subsys(&tcpv6_net_ops);
2024 	if (ret)
2025 		goto out_tcpv6_protosw;
2026 out:
2027 	return ret;
2028 
2029 out_tcpv6_protosw:
2030 	inet6_unregister_protosw(&tcpv6_protosw);
2031 out_tcpv6_protocol:
2032 	inet6_del_protocol(&tcpv6_protocol, IPPROTO_TCP);
2033 	goto out;
2034 }
2035 
2036 void tcpv6_exit(void)
2037 {
2038 	unregister_pernet_subsys(&tcpv6_net_ops);
2039 	inet6_unregister_protosw(&tcpv6_protosw);
2040 	inet6_del_protocol(&tcpv6_protocol, IPPROTO_TCP);
2041 }
2042