xref: /openbmc/linux/net/ipv6/tcp_ipv6.c (revision 46d3ceabd8d98ed0ad10f20c595ca784e34786c5)
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 static void	__tcp_v6_send_check(struct sk_buff *skb,
81 				    const struct in6_addr *saddr,
82 				    const struct in6_addr *daddr);
83 
84 static const struct inet_connection_sock_af_ops ipv6_mapped;
85 static const struct inet_connection_sock_af_ops ipv6_specific;
86 #ifdef CONFIG_TCP_MD5SIG
87 static const struct tcp_sock_af_ops tcp_sock_ipv6_specific;
88 static const struct tcp_sock_af_ops tcp_sock_ipv6_mapped_specific;
89 #else
90 static struct tcp_md5sig_key *tcp_v6_md5_do_lookup(struct sock *sk,
91 						   const struct in6_addr *addr)
92 {
93 	return NULL;
94 }
95 #endif
96 
97 static void tcp_v6_hash(struct sock *sk)
98 {
99 	if (sk->sk_state != TCP_CLOSE) {
100 		if (inet_csk(sk)->icsk_af_ops == &ipv6_mapped) {
101 			tcp_prot.hash(sk);
102 			return;
103 		}
104 		local_bh_disable();
105 		__inet6_hash(sk, NULL);
106 		local_bh_enable();
107 	}
108 }
109 
110 static __inline__ __sum16 tcp_v6_check(int len,
111 				   const struct in6_addr *saddr,
112 				   const struct in6_addr *daddr,
113 				   __wsum base)
114 {
115 	return csum_ipv6_magic(saddr, daddr, len, IPPROTO_TCP, base);
116 }
117 
118 static __u32 tcp_v6_init_sequence(const struct sk_buff *skb)
119 {
120 	return secure_tcpv6_sequence_number(ipv6_hdr(skb)->daddr.s6_addr32,
121 					    ipv6_hdr(skb)->saddr.s6_addr32,
122 					    tcp_hdr(skb)->dest,
123 					    tcp_hdr(skb)->source);
124 }
125 
126 static int tcp_v6_connect(struct sock *sk, struct sockaddr *uaddr,
127 			  int addr_len)
128 {
129 	struct sockaddr_in6 *usin = (struct sockaddr_in6 *) uaddr;
130 	struct inet_sock *inet = inet_sk(sk);
131 	struct inet_connection_sock *icsk = inet_csk(sk);
132 	struct ipv6_pinfo *np = inet6_sk(sk);
133 	struct tcp_sock *tp = tcp_sk(sk);
134 	struct in6_addr *saddr = NULL, *final_p, final;
135 	struct rt6_info *rt;
136 	struct flowi6 fl6;
137 	struct dst_entry *dst;
138 	int addr_type;
139 	int err;
140 
141 	if (addr_len < SIN6_LEN_RFC2133)
142 		return -EINVAL;
143 
144 	if (usin->sin6_family != AF_INET6)
145 		return -EAFNOSUPPORT;
146 
147 	memset(&fl6, 0, sizeof(fl6));
148 
149 	if (np->sndflow) {
150 		fl6.flowlabel = usin->sin6_flowinfo&IPV6_FLOWINFO_MASK;
151 		IP6_ECN_flow_init(fl6.flowlabel);
152 		if (fl6.flowlabel&IPV6_FLOWLABEL_MASK) {
153 			struct ip6_flowlabel *flowlabel;
154 			flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
155 			if (flowlabel == NULL)
156 				return -EINVAL;
157 			usin->sin6_addr = flowlabel->dst;
158 			fl6_sock_release(flowlabel);
159 		}
160 	}
161 
162 	/*
163 	 *	connect() to INADDR_ANY means loopback (BSD'ism).
164 	 */
165 
166 	if(ipv6_addr_any(&usin->sin6_addr))
167 		usin->sin6_addr.s6_addr[15] = 0x1;
168 
169 	addr_type = ipv6_addr_type(&usin->sin6_addr);
170 
171 	if(addr_type & IPV6_ADDR_MULTICAST)
172 		return -ENETUNREACH;
173 
174 	if (addr_type&IPV6_ADDR_LINKLOCAL) {
175 		if (addr_len >= sizeof(struct sockaddr_in6) &&
176 		    usin->sin6_scope_id) {
177 			/* If interface is set while binding, indices
178 			 * must coincide.
179 			 */
180 			if (sk->sk_bound_dev_if &&
181 			    sk->sk_bound_dev_if != usin->sin6_scope_id)
182 				return -EINVAL;
183 
184 			sk->sk_bound_dev_if = usin->sin6_scope_id;
185 		}
186 
187 		/* Connect to link-local address requires an interface */
188 		if (!sk->sk_bound_dev_if)
189 			return -EINVAL;
190 	}
191 
192 	if (tp->rx_opt.ts_recent_stamp &&
193 	    !ipv6_addr_equal(&np->daddr, &usin->sin6_addr)) {
194 		tp->rx_opt.ts_recent = 0;
195 		tp->rx_opt.ts_recent_stamp = 0;
196 		tp->write_seq = 0;
197 	}
198 
199 	np->daddr = usin->sin6_addr;
200 	np->flow_label = fl6.flowlabel;
201 
202 	/*
203 	 *	TCP over IPv4
204 	 */
205 
206 	if (addr_type == IPV6_ADDR_MAPPED) {
207 		u32 exthdrlen = icsk->icsk_ext_hdr_len;
208 		struct sockaddr_in sin;
209 
210 		SOCK_DEBUG(sk, "connect: ipv4 mapped\n");
211 
212 		if (__ipv6_only_sock(sk))
213 			return -ENETUNREACH;
214 
215 		sin.sin_family = AF_INET;
216 		sin.sin_port = usin->sin6_port;
217 		sin.sin_addr.s_addr = usin->sin6_addr.s6_addr32[3];
218 
219 		icsk->icsk_af_ops = &ipv6_mapped;
220 		sk->sk_backlog_rcv = tcp_v4_do_rcv;
221 #ifdef CONFIG_TCP_MD5SIG
222 		tp->af_specific = &tcp_sock_ipv6_mapped_specific;
223 #endif
224 
225 		err = tcp_v4_connect(sk, (struct sockaddr *)&sin, sizeof(sin));
226 
227 		if (err) {
228 			icsk->icsk_ext_hdr_len = exthdrlen;
229 			icsk->icsk_af_ops = &ipv6_specific;
230 			sk->sk_backlog_rcv = tcp_v6_do_rcv;
231 #ifdef CONFIG_TCP_MD5SIG
232 			tp->af_specific = &tcp_sock_ipv6_specific;
233 #endif
234 			goto failure;
235 		} else {
236 			ipv6_addr_set_v4mapped(inet->inet_saddr, &np->saddr);
237 			ipv6_addr_set_v4mapped(inet->inet_rcv_saddr,
238 					       &np->rcv_saddr);
239 		}
240 
241 		return err;
242 	}
243 
244 	if (!ipv6_addr_any(&np->rcv_saddr))
245 		saddr = &np->rcv_saddr;
246 
247 	fl6.flowi6_proto = IPPROTO_TCP;
248 	fl6.daddr = np->daddr;
249 	fl6.saddr = saddr ? *saddr : np->saddr;
250 	fl6.flowi6_oif = sk->sk_bound_dev_if;
251 	fl6.flowi6_mark = sk->sk_mark;
252 	fl6.fl6_dport = usin->sin6_port;
253 	fl6.fl6_sport = inet->inet_sport;
254 
255 	final_p = fl6_update_dst(&fl6, np->opt, &final);
256 
257 	security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));
258 
259 	dst = ip6_dst_lookup_flow(sk, &fl6, final_p, true);
260 	if (IS_ERR(dst)) {
261 		err = PTR_ERR(dst);
262 		goto failure;
263 	}
264 
265 	if (saddr == NULL) {
266 		saddr = &fl6.saddr;
267 		np->rcv_saddr = *saddr;
268 	}
269 
270 	/* set the source address */
271 	np->saddr = *saddr;
272 	inet->inet_rcv_saddr = LOOPBACK4_IPV6;
273 
274 	sk->sk_gso_type = SKB_GSO_TCPV6;
275 	__ip6_dst_store(sk, dst, NULL, NULL);
276 
277 	rt = (struct rt6_info *) dst;
278 	if (tcp_death_row.sysctl_tw_recycle &&
279 	    !tp->rx_opt.ts_recent_stamp &&
280 	    ipv6_addr_equal(&rt->rt6i_dst.addr, &np->daddr))
281 		tcp_fetch_timewait_stamp(sk, dst);
282 
283 	icsk->icsk_ext_hdr_len = 0;
284 	if (np->opt)
285 		icsk->icsk_ext_hdr_len = (np->opt->opt_flen +
286 					  np->opt->opt_nflen);
287 
288 	tp->rx_opt.mss_clamp = IPV6_MIN_MTU - sizeof(struct tcphdr) - sizeof(struct ipv6hdr);
289 
290 	inet->inet_dport = usin->sin6_port;
291 
292 	tcp_set_state(sk, TCP_SYN_SENT);
293 	err = inet6_hash_connect(&tcp_death_row, sk);
294 	if (err)
295 		goto late_failure;
296 
297 	if (!tp->write_seq)
298 		tp->write_seq = secure_tcpv6_sequence_number(np->saddr.s6_addr32,
299 							     np->daddr.s6_addr32,
300 							     inet->inet_sport,
301 							     inet->inet_dport);
302 
303 	err = tcp_connect(sk);
304 	if (err)
305 		goto late_failure;
306 
307 	return 0;
308 
309 late_failure:
310 	tcp_set_state(sk, TCP_CLOSE);
311 	__sk_dst_reset(sk);
312 failure:
313 	inet->inet_dport = 0;
314 	sk->sk_route_caps = 0;
315 	return err;
316 }
317 
318 static void tcp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
319 		u8 type, u8 code, int offset, __be32 info)
320 {
321 	const struct ipv6hdr *hdr = (const struct ipv6hdr*)skb->data;
322 	const struct tcphdr *th = (struct tcphdr *)(skb->data+offset);
323 	struct ipv6_pinfo *np;
324 	struct sock *sk;
325 	int err;
326 	struct tcp_sock *tp;
327 	__u32 seq;
328 	struct net *net = dev_net(skb->dev);
329 
330 	sk = inet6_lookup(net, &tcp_hashinfo, &hdr->daddr,
331 			th->dest, &hdr->saddr, th->source, skb->dev->ifindex);
332 
333 	if (sk == NULL) {
334 		ICMP6_INC_STATS_BH(net, __in6_dev_get(skb->dev),
335 				   ICMP6_MIB_INERRORS);
336 		return;
337 	}
338 
339 	if (sk->sk_state == TCP_TIME_WAIT) {
340 		inet_twsk_put(inet_twsk(sk));
341 		return;
342 	}
343 
344 	bh_lock_sock(sk);
345 	if (sock_owned_by_user(sk))
346 		NET_INC_STATS_BH(net, LINUX_MIB_LOCKDROPPEDICMPS);
347 
348 	if (sk->sk_state == TCP_CLOSE)
349 		goto out;
350 
351 	if (ipv6_hdr(skb)->hop_limit < inet6_sk(sk)->min_hopcount) {
352 		NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP);
353 		goto out;
354 	}
355 
356 	tp = tcp_sk(sk);
357 	seq = ntohl(th->seq);
358 	if (sk->sk_state != TCP_LISTEN &&
359 	    !between(seq, tp->snd_una, tp->snd_nxt)) {
360 		NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
361 		goto out;
362 	}
363 
364 	np = inet6_sk(sk);
365 
366 	if (type == ICMPV6_PKT_TOOBIG) {
367 		struct dst_entry *dst;
368 
369 		if (sock_owned_by_user(sk))
370 			goto out;
371 		if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE))
372 			goto out;
373 
374 		/* icmp should have updated the destination cache entry */
375 		dst = __sk_dst_check(sk, np->dst_cookie);
376 
377 		if (dst == NULL) {
378 			struct inet_sock *inet = inet_sk(sk);
379 			struct flowi6 fl6;
380 
381 			/* BUGGG_FUTURE: Again, it is not clear how
382 			   to handle rthdr case. Ignore this complexity
383 			   for now.
384 			 */
385 			memset(&fl6, 0, sizeof(fl6));
386 			fl6.flowi6_proto = IPPROTO_TCP;
387 			fl6.daddr = np->daddr;
388 			fl6.saddr = np->saddr;
389 			fl6.flowi6_oif = sk->sk_bound_dev_if;
390 			fl6.flowi6_mark = sk->sk_mark;
391 			fl6.fl6_dport = inet->inet_dport;
392 			fl6.fl6_sport = inet->inet_sport;
393 			security_skb_classify_flow(skb, flowi6_to_flowi(&fl6));
394 
395 			dst = ip6_dst_lookup_flow(sk, &fl6, NULL, false);
396 			if (IS_ERR(dst)) {
397 				sk->sk_err_soft = -PTR_ERR(dst);
398 				goto out;
399 			}
400 
401 		} else
402 			dst_hold(dst);
403 
404 		dst->ops->update_pmtu(dst, ntohl(info));
405 
406 		if (inet_csk(sk)->icsk_pmtu_cookie > dst_mtu(dst)) {
407 			tcp_sync_mss(sk, dst_mtu(dst));
408 			tcp_simple_retransmit(sk);
409 		} /* else let the usual retransmit timer handle it */
410 		dst_release(dst);
411 		goto out;
412 	}
413 
414 	icmpv6_err_convert(type, code, &err);
415 
416 	/* Might be for an request_sock */
417 	switch (sk->sk_state) {
418 		struct request_sock *req, **prev;
419 	case TCP_LISTEN:
420 		if (sock_owned_by_user(sk))
421 			goto out;
422 
423 		req = inet6_csk_search_req(sk, &prev, th->dest, &hdr->daddr,
424 					   &hdr->saddr, inet6_iif(skb));
425 		if (!req)
426 			goto out;
427 
428 		/* ICMPs are not backlogged, hence we cannot get
429 		 * an established socket here.
430 		 */
431 		WARN_ON(req->sk != NULL);
432 
433 		if (seq != tcp_rsk(req)->snt_isn) {
434 			NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
435 			goto out;
436 		}
437 
438 		inet_csk_reqsk_queue_drop(sk, req, prev);
439 		goto out;
440 
441 	case TCP_SYN_SENT:
442 	case TCP_SYN_RECV:  /* Cannot happen.
443 			       It can, it SYNs are crossed. --ANK */
444 		if (!sock_owned_by_user(sk)) {
445 			sk->sk_err = err;
446 			sk->sk_error_report(sk);		/* Wake people up to see the error (see connect in sock.c) */
447 
448 			tcp_done(sk);
449 		} else
450 			sk->sk_err_soft = err;
451 		goto out;
452 	}
453 
454 	if (!sock_owned_by_user(sk) && np->recverr) {
455 		sk->sk_err = err;
456 		sk->sk_error_report(sk);
457 	} else
458 		sk->sk_err_soft = err;
459 
460 out:
461 	bh_unlock_sock(sk);
462 	sock_put(sk);
463 }
464 
465 
466 static int tcp_v6_send_synack(struct sock *sk, struct dst_entry *dst,
467 			      struct flowi6 *fl6,
468 			      struct request_sock *req,
469 			      struct request_values *rvp,
470 			      u16 queue_mapping)
471 {
472 	struct inet6_request_sock *treq = inet6_rsk(req);
473 	struct ipv6_pinfo *np = inet6_sk(sk);
474 	struct sk_buff * skb;
475 	int err = -ENOMEM;
476 
477 	/* First, grab a route. */
478 	if (!dst && (dst = inet6_csk_route_req(sk, fl6, req)) == NULL)
479 		goto done;
480 
481 	skb = tcp_make_synack(sk, dst, req, rvp);
482 
483 	if (skb) {
484 		__tcp_v6_send_check(skb, &treq->loc_addr, &treq->rmt_addr);
485 
486 		fl6->daddr = treq->rmt_addr;
487 		skb_set_queue_mapping(skb, queue_mapping);
488 		err = ip6_xmit(sk, skb, fl6, np->opt, np->tclass);
489 		err = net_xmit_eval(err);
490 	}
491 
492 done:
493 	return err;
494 }
495 
496 static int tcp_v6_rtx_synack(struct sock *sk, struct request_sock *req,
497 			     struct request_values *rvp)
498 {
499 	struct flowi6 fl6;
500 
501 	TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_RETRANSSEGS);
502 	return tcp_v6_send_synack(sk, NULL, &fl6, req, rvp, 0);
503 }
504 
505 static void tcp_v6_reqsk_destructor(struct request_sock *req)
506 {
507 	kfree_skb(inet6_rsk(req)->pktopts);
508 }
509 
510 #ifdef CONFIG_TCP_MD5SIG
511 static struct tcp_md5sig_key *tcp_v6_md5_do_lookup(struct sock *sk,
512 						   const struct in6_addr *addr)
513 {
514 	return tcp_md5_do_lookup(sk, (union tcp_md5_addr *)addr, AF_INET6);
515 }
516 
517 static struct tcp_md5sig_key *tcp_v6_md5_lookup(struct sock *sk,
518 						struct sock *addr_sk)
519 {
520 	return tcp_v6_md5_do_lookup(sk, &inet6_sk(addr_sk)->daddr);
521 }
522 
523 static struct tcp_md5sig_key *tcp_v6_reqsk_md5_lookup(struct sock *sk,
524 						      struct request_sock *req)
525 {
526 	return tcp_v6_md5_do_lookup(sk, &inet6_rsk(req)->rmt_addr);
527 }
528 
529 static int tcp_v6_parse_md5_keys (struct sock *sk, char __user *optval,
530 				  int optlen)
531 {
532 	struct tcp_md5sig cmd;
533 	struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)&cmd.tcpm_addr;
534 
535 	if (optlen < sizeof(cmd))
536 		return -EINVAL;
537 
538 	if (copy_from_user(&cmd, optval, sizeof(cmd)))
539 		return -EFAULT;
540 
541 	if (sin6->sin6_family != AF_INET6)
542 		return -EINVAL;
543 
544 	if (!cmd.tcpm_keylen) {
545 		if (ipv6_addr_v4mapped(&sin6->sin6_addr))
546 			return tcp_md5_do_del(sk, (union tcp_md5_addr *)&sin6->sin6_addr.s6_addr32[3],
547 					      AF_INET);
548 		return tcp_md5_do_del(sk, (union tcp_md5_addr *)&sin6->sin6_addr,
549 				      AF_INET6);
550 	}
551 
552 	if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN)
553 		return -EINVAL;
554 
555 	if (ipv6_addr_v4mapped(&sin6->sin6_addr))
556 		return tcp_md5_do_add(sk, (union tcp_md5_addr *)&sin6->sin6_addr.s6_addr32[3],
557 				      AF_INET, cmd.tcpm_key, cmd.tcpm_keylen, GFP_KERNEL);
558 
559 	return tcp_md5_do_add(sk, (union tcp_md5_addr *)&sin6->sin6_addr,
560 			      AF_INET6, cmd.tcpm_key, cmd.tcpm_keylen, GFP_KERNEL);
561 }
562 
563 static int tcp_v6_md5_hash_pseudoheader(struct tcp_md5sig_pool *hp,
564 					const struct in6_addr *daddr,
565 					const struct in6_addr *saddr, int nbytes)
566 {
567 	struct tcp6_pseudohdr *bp;
568 	struct scatterlist sg;
569 
570 	bp = &hp->md5_blk.ip6;
571 	/* 1. TCP pseudo-header (RFC2460) */
572 	bp->saddr = *saddr;
573 	bp->daddr = *daddr;
574 	bp->protocol = cpu_to_be32(IPPROTO_TCP);
575 	bp->len = cpu_to_be32(nbytes);
576 
577 	sg_init_one(&sg, bp, sizeof(*bp));
578 	return crypto_hash_update(&hp->md5_desc, &sg, sizeof(*bp));
579 }
580 
581 static int tcp_v6_md5_hash_hdr(char *md5_hash, struct tcp_md5sig_key *key,
582 			       const struct in6_addr *daddr, struct in6_addr *saddr,
583 			       const struct tcphdr *th)
584 {
585 	struct tcp_md5sig_pool *hp;
586 	struct hash_desc *desc;
587 
588 	hp = tcp_get_md5sig_pool();
589 	if (!hp)
590 		goto clear_hash_noput;
591 	desc = &hp->md5_desc;
592 
593 	if (crypto_hash_init(desc))
594 		goto clear_hash;
595 	if (tcp_v6_md5_hash_pseudoheader(hp, daddr, saddr, th->doff << 2))
596 		goto clear_hash;
597 	if (tcp_md5_hash_header(hp, th))
598 		goto clear_hash;
599 	if (tcp_md5_hash_key(hp, key))
600 		goto clear_hash;
601 	if (crypto_hash_final(desc, md5_hash))
602 		goto clear_hash;
603 
604 	tcp_put_md5sig_pool();
605 	return 0;
606 
607 clear_hash:
608 	tcp_put_md5sig_pool();
609 clear_hash_noput:
610 	memset(md5_hash, 0, 16);
611 	return 1;
612 }
613 
614 static int tcp_v6_md5_hash_skb(char *md5_hash, struct tcp_md5sig_key *key,
615 			       const struct sock *sk,
616 			       const struct request_sock *req,
617 			       const struct sk_buff *skb)
618 {
619 	const struct in6_addr *saddr, *daddr;
620 	struct tcp_md5sig_pool *hp;
621 	struct hash_desc *desc;
622 	const struct tcphdr *th = tcp_hdr(skb);
623 
624 	if (sk) {
625 		saddr = &inet6_sk(sk)->saddr;
626 		daddr = &inet6_sk(sk)->daddr;
627 	} else if (req) {
628 		saddr = &inet6_rsk(req)->loc_addr;
629 		daddr = &inet6_rsk(req)->rmt_addr;
630 	} else {
631 		const struct ipv6hdr *ip6h = ipv6_hdr(skb);
632 		saddr = &ip6h->saddr;
633 		daddr = &ip6h->daddr;
634 	}
635 
636 	hp = tcp_get_md5sig_pool();
637 	if (!hp)
638 		goto clear_hash_noput;
639 	desc = &hp->md5_desc;
640 
641 	if (crypto_hash_init(desc))
642 		goto clear_hash;
643 
644 	if (tcp_v6_md5_hash_pseudoheader(hp, daddr, saddr, skb->len))
645 		goto clear_hash;
646 	if (tcp_md5_hash_header(hp, th))
647 		goto clear_hash;
648 	if (tcp_md5_hash_skb_data(hp, skb, th->doff << 2))
649 		goto clear_hash;
650 	if (tcp_md5_hash_key(hp, key))
651 		goto clear_hash;
652 	if (crypto_hash_final(desc, md5_hash))
653 		goto clear_hash;
654 
655 	tcp_put_md5sig_pool();
656 	return 0;
657 
658 clear_hash:
659 	tcp_put_md5sig_pool();
660 clear_hash_noput:
661 	memset(md5_hash, 0, 16);
662 	return 1;
663 }
664 
665 static int tcp_v6_inbound_md5_hash(struct sock *sk, const struct sk_buff *skb)
666 {
667 	const __u8 *hash_location = NULL;
668 	struct tcp_md5sig_key *hash_expected;
669 	const struct ipv6hdr *ip6h = ipv6_hdr(skb);
670 	const struct tcphdr *th = tcp_hdr(skb);
671 	int genhash;
672 	u8 newhash[16];
673 
674 	hash_expected = tcp_v6_md5_do_lookup(sk, &ip6h->saddr);
675 	hash_location = tcp_parse_md5sig_option(th);
676 
677 	/* We've parsed the options - do we have a hash? */
678 	if (!hash_expected && !hash_location)
679 		return 0;
680 
681 	if (hash_expected && !hash_location) {
682 		NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5NOTFOUND);
683 		return 1;
684 	}
685 
686 	if (!hash_expected && hash_location) {
687 		NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5UNEXPECTED);
688 		return 1;
689 	}
690 
691 	/* check the signature */
692 	genhash = tcp_v6_md5_hash_skb(newhash,
693 				      hash_expected,
694 				      NULL, NULL, skb);
695 
696 	if (genhash || memcmp(hash_location, newhash, 16) != 0) {
697 		net_info_ratelimited("MD5 Hash %s for [%pI6c]:%u->[%pI6c]:%u\n",
698 				     genhash ? "failed" : "mismatch",
699 				     &ip6h->saddr, ntohs(th->source),
700 				     &ip6h->daddr, ntohs(th->dest));
701 		return 1;
702 	}
703 	return 0;
704 }
705 #endif
706 
707 struct request_sock_ops tcp6_request_sock_ops __read_mostly = {
708 	.family		=	AF_INET6,
709 	.obj_size	=	sizeof(struct tcp6_request_sock),
710 	.rtx_syn_ack	=	tcp_v6_rtx_synack,
711 	.send_ack	=	tcp_v6_reqsk_send_ack,
712 	.destructor	=	tcp_v6_reqsk_destructor,
713 	.send_reset	=	tcp_v6_send_reset,
714 	.syn_ack_timeout = 	tcp_syn_ack_timeout,
715 };
716 
717 #ifdef CONFIG_TCP_MD5SIG
718 static const struct tcp_request_sock_ops tcp_request_sock_ipv6_ops = {
719 	.md5_lookup	=	tcp_v6_reqsk_md5_lookup,
720 	.calc_md5_hash	=	tcp_v6_md5_hash_skb,
721 };
722 #endif
723 
724 static void __tcp_v6_send_check(struct sk_buff *skb,
725 				const struct in6_addr *saddr, const struct in6_addr *daddr)
726 {
727 	struct tcphdr *th = tcp_hdr(skb);
728 
729 	if (skb->ip_summed == CHECKSUM_PARTIAL) {
730 		th->check = ~tcp_v6_check(skb->len, saddr, daddr, 0);
731 		skb->csum_start = skb_transport_header(skb) - skb->head;
732 		skb->csum_offset = offsetof(struct tcphdr, check);
733 	} else {
734 		th->check = tcp_v6_check(skb->len, saddr, daddr,
735 					 csum_partial(th, th->doff << 2,
736 						      skb->csum));
737 	}
738 }
739 
740 static void tcp_v6_send_check(struct sock *sk, struct sk_buff *skb)
741 {
742 	struct ipv6_pinfo *np = inet6_sk(sk);
743 
744 	__tcp_v6_send_check(skb, &np->saddr, &np->daddr);
745 }
746 
747 static int tcp_v6_gso_send_check(struct sk_buff *skb)
748 {
749 	const struct ipv6hdr *ipv6h;
750 	struct tcphdr *th;
751 
752 	if (!pskb_may_pull(skb, sizeof(*th)))
753 		return -EINVAL;
754 
755 	ipv6h = ipv6_hdr(skb);
756 	th = tcp_hdr(skb);
757 
758 	th->check = 0;
759 	skb->ip_summed = CHECKSUM_PARTIAL;
760 	__tcp_v6_send_check(skb, &ipv6h->saddr, &ipv6h->daddr);
761 	return 0;
762 }
763 
764 static struct sk_buff **tcp6_gro_receive(struct sk_buff **head,
765 					 struct sk_buff *skb)
766 {
767 	const struct ipv6hdr *iph = skb_gro_network_header(skb);
768 
769 	switch (skb->ip_summed) {
770 	case CHECKSUM_COMPLETE:
771 		if (!tcp_v6_check(skb_gro_len(skb), &iph->saddr, &iph->daddr,
772 				  skb->csum)) {
773 			skb->ip_summed = CHECKSUM_UNNECESSARY;
774 			break;
775 		}
776 
777 		/* fall through */
778 	case CHECKSUM_NONE:
779 		NAPI_GRO_CB(skb)->flush = 1;
780 		return NULL;
781 	}
782 
783 	return tcp_gro_receive(head, skb);
784 }
785 
786 static int tcp6_gro_complete(struct sk_buff *skb)
787 {
788 	const struct ipv6hdr *iph = ipv6_hdr(skb);
789 	struct tcphdr *th = tcp_hdr(skb);
790 
791 	th->check = ~tcp_v6_check(skb->len - skb_transport_offset(skb),
792 				  &iph->saddr, &iph->daddr, 0);
793 	skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
794 
795 	return tcp_gro_complete(skb);
796 }
797 
798 static void tcp_v6_send_response(struct sk_buff *skb, u32 seq, u32 ack, u32 win,
799 				 u32 ts, struct tcp_md5sig_key *key, int rst, u8 tclass)
800 {
801 	const struct tcphdr *th = tcp_hdr(skb);
802 	struct tcphdr *t1;
803 	struct sk_buff *buff;
804 	struct flowi6 fl6;
805 	struct net *net = dev_net(skb_dst(skb)->dev);
806 	struct sock *ctl_sk = net->ipv6.tcp_sk;
807 	unsigned int tot_len = sizeof(struct tcphdr);
808 	struct dst_entry *dst;
809 	__be32 *topt;
810 
811 	if (ts)
812 		tot_len += TCPOLEN_TSTAMP_ALIGNED;
813 #ifdef CONFIG_TCP_MD5SIG
814 	if (key)
815 		tot_len += TCPOLEN_MD5SIG_ALIGNED;
816 #endif
817 
818 	buff = alloc_skb(MAX_HEADER + sizeof(struct ipv6hdr) + tot_len,
819 			 GFP_ATOMIC);
820 	if (buff == NULL)
821 		return;
822 
823 	skb_reserve(buff, MAX_HEADER + sizeof(struct ipv6hdr) + tot_len);
824 
825 	t1 = (struct tcphdr *) skb_push(buff, tot_len);
826 	skb_reset_transport_header(buff);
827 
828 	/* Swap the send and the receive. */
829 	memset(t1, 0, sizeof(*t1));
830 	t1->dest = th->source;
831 	t1->source = th->dest;
832 	t1->doff = tot_len / 4;
833 	t1->seq = htonl(seq);
834 	t1->ack_seq = htonl(ack);
835 	t1->ack = !rst || !th->ack;
836 	t1->rst = rst;
837 	t1->window = htons(win);
838 
839 	topt = (__be32 *)(t1 + 1);
840 
841 	if (ts) {
842 		*topt++ = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
843 				(TCPOPT_TIMESTAMP << 8) | TCPOLEN_TIMESTAMP);
844 		*topt++ = htonl(tcp_time_stamp);
845 		*topt++ = htonl(ts);
846 	}
847 
848 #ifdef CONFIG_TCP_MD5SIG
849 	if (key) {
850 		*topt++ = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
851 				(TCPOPT_MD5SIG << 8) | TCPOLEN_MD5SIG);
852 		tcp_v6_md5_hash_hdr((__u8 *)topt, key,
853 				    &ipv6_hdr(skb)->saddr,
854 				    &ipv6_hdr(skb)->daddr, t1);
855 	}
856 #endif
857 
858 	memset(&fl6, 0, sizeof(fl6));
859 	fl6.daddr = ipv6_hdr(skb)->saddr;
860 	fl6.saddr = ipv6_hdr(skb)->daddr;
861 
862 	buff->ip_summed = CHECKSUM_PARTIAL;
863 	buff->csum = 0;
864 
865 	__tcp_v6_send_check(buff, &fl6.saddr, &fl6.daddr);
866 
867 	fl6.flowi6_proto = IPPROTO_TCP;
868 	fl6.flowi6_oif = inet6_iif(skb);
869 	fl6.fl6_dport = t1->dest;
870 	fl6.fl6_sport = t1->source;
871 	security_skb_classify_flow(skb, flowi6_to_flowi(&fl6));
872 
873 	/* Pass a socket to ip6_dst_lookup either it is for RST
874 	 * Underlying function will use this to retrieve the network
875 	 * namespace
876 	 */
877 	dst = ip6_dst_lookup_flow(ctl_sk, &fl6, NULL, false);
878 	if (!IS_ERR(dst)) {
879 		skb_dst_set(buff, dst);
880 		ip6_xmit(ctl_sk, buff, &fl6, NULL, tclass);
881 		TCP_INC_STATS_BH(net, TCP_MIB_OUTSEGS);
882 		if (rst)
883 			TCP_INC_STATS_BH(net, TCP_MIB_OUTRSTS);
884 		return;
885 	}
886 
887 	kfree_skb(buff);
888 }
889 
890 static void tcp_v6_send_reset(struct sock *sk, struct sk_buff *skb)
891 {
892 	const struct tcphdr *th = tcp_hdr(skb);
893 	u32 seq = 0, ack_seq = 0;
894 	struct tcp_md5sig_key *key = NULL;
895 #ifdef CONFIG_TCP_MD5SIG
896 	const __u8 *hash_location = NULL;
897 	struct ipv6hdr *ipv6h = ipv6_hdr(skb);
898 	unsigned char newhash[16];
899 	int genhash;
900 	struct sock *sk1 = NULL;
901 #endif
902 
903 	if (th->rst)
904 		return;
905 
906 	if (!ipv6_unicast_destination(skb))
907 		return;
908 
909 #ifdef CONFIG_TCP_MD5SIG
910 	hash_location = tcp_parse_md5sig_option(th);
911 	if (!sk && hash_location) {
912 		/*
913 		 * active side is lost. Try to find listening socket through
914 		 * source port, and then find md5 key through listening socket.
915 		 * we are not loose security here:
916 		 * Incoming packet is checked with md5 hash with finding key,
917 		 * no RST generated if md5 hash doesn't match.
918 		 */
919 		sk1 = inet6_lookup_listener(dev_net(skb_dst(skb)->dev),
920 					   &tcp_hashinfo, &ipv6h->daddr,
921 					   ntohs(th->source), inet6_iif(skb));
922 		if (!sk1)
923 			return;
924 
925 		rcu_read_lock();
926 		key = tcp_v6_md5_do_lookup(sk1, &ipv6h->saddr);
927 		if (!key)
928 			goto release_sk1;
929 
930 		genhash = tcp_v6_md5_hash_skb(newhash, key, NULL, NULL, skb);
931 		if (genhash || memcmp(hash_location, newhash, 16) != 0)
932 			goto release_sk1;
933 	} else {
934 		key = sk ? tcp_v6_md5_do_lookup(sk, &ipv6h->saddr) : NULL;
935 	}
936 #endif
937 
938 	if (th->ack)
939 		seq = ntohl(th->ack_seq);
940 	else
941 		ack_seq = ntohl(th->seq) + th->syn + th->fin + skb->len -
942 			  (th->doff << 2);
943 
944 	tcp_v6_send_response(skb, seq, ack_seq, 0, 0, key, 1, 0);
945 
946 #ifdef CONFIG_TCP_MD5SIG
947 release_sk1:
948 	if (sk1) {
949 		rcu_read_unlock();
950 		sock_put(sk1);
951 	}
952 #endif
953 }
954 
955 static void tcp_v6_send_ack(struct sk_buff *skb, u32 seq, u32 ack, u32 win, u32 ts,
956 			    struct tcp_md5sig_key *key, u8 tclass)
957 {
958 	tcp_v6_send_response(skb, seq, ack, win, ts, key, 0, tclass);
959 }
960 
961 static void tcp_v6_timewait_ack(struct sock *sk, struct sk_buff *skb)
962 {
963 	struct inet_timewait_sock *tw = inet_twsk(sk);
964 	struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
965 
966 	tcp_v6_send_ack(skb, tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
967 			tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
968 			tcptw->tw_ts_recent, tcp_twsk_md5_key(tcptw),
969 			tw->tw_tclass);
970 
971 	inet_twsk_put(tw);
972 }
973 
974 static void tcp_v6_reqsk_send_ack(struct sock *sk, struct sk_buff *skb,
975 				  struct request_sock *req)
976 {
977 	tcp_v6_send_ack(skb, tcp_rsk(req)->snt_isn + 1, tcp_rsk(req)->rcv_isn + 1, req->rcv_wnd, req->ts_recent,
978 			tcp_v6_md5_do_lookup(sk, &ipv6_hdr(skb)->daddr), 0);
979 }
980 
981 
982 static struct sock *tcp_v6_hnd_req(struct sock *sk,struct sk_buff *skb)
983 {
984 	struct request_sock *req, **prev;
985 	const struct tcphdr *th = tcp_hdr(skb);
986 	struct sock *nsk;
987 
988 	/* Find possible connection requests. */
989 	req = inet6_csk_search_req(sk, &prev, th->source,
990 				   &ipv6_hdr(skb)->saddr,
991 				   &ipv6_hdr(skb)->daddr, inet6_iif(skb));
992 	if (req)
993 		return tcp_check_req(sk, skb, req, prev);
994 
995 	nsk = __inet6_lookup_established(sock_net(sk), &tcp_hashinfo,
996 			&ipv6_hdr(skb)->saddr, th->source,
997 			&ipv6_hdr(skb)->daddr, ntohs(th->dest), inet6_iif(skb));
998 
999 	if (nsk) {
1000 		if (nsk->sk_state != TCP_TIME_WAIT) {
1001 			bh_lock_sock(nsk);
1002 			return nsk;
1003 		}
1004 		inet_twsk_put(inet_twsk(nsk));
1005 		return NULL;
1006 	}
1007 
1008 #ifdef CONFIG_SYN_COOKIES
1009 	if (!th->syn)
1010 		sk = cookie_v6_check(sk, skb);
1011 #endif
1012 	return sk;
1013 }
1014 
1015 /* FIXME: this is substantially similar to the ipv4 code.
1016  * Can some kind of merge be done? -- erics
1017  */
1018 static int tcp_v6_conn_request(struct sock *sk, struct sk_buff *skb)
1019 {
1020 	struct tcp_extend_values tmp_ext;
1021 	struct tcp_options_received tmp_opt;
1022 	const u8 *hash_location;
1023 	struct request_sock *req;
1024 	struct inet6_request_sock *treq;
1025 	struct ipv6_pinfo *np = inet6_sk(sk);
1026 	struct tcp_sock *tp = tcp_sk(sk);
1027 	__u32 isn = TCP_SKB_CB(skb)->when;
1028 	struct dst_entry *dst = NULL;
1029 	struct flowi6 fl6;
1030 	bool want_cookie = false;
1031 
1032 	if (skb->protocol == htons(ETH_P_IP))
1033 		return tcp_v4_conn_request(sk, skb);
1034 
1035 	if (!ipv6_unicast_destination(skb))
1036 		goto drop;
1037 
1038 	if (inet_csk_reqsk_queue_is_full(sk) && !isn) {
1039 		want_cookie = tcp_syn_flood_action(sk, skb, "TCPv6");
1040 		if (!want_cookie)
1041 			goto drop;
1042 	}
1043 
1044 	if (sk_acceptq_is_full(sk) && inet_csk_reqsk_queue_young(sk) > 1)
1045 		goto drop;
1046 
1047 	req = inet6_reqsk_alloc(&tcp6_request_sock_ops);
1048 	if (req == NULL)
1049 		goto drop;
1050 
1051 #ifdef CONFIG_TCP_MD5SIG
1052 	tcp_rsk(req)->af_specific = &tcp_request_sock_ipv6_ops;
1053 #endif
1054 
1055 	tcp_clear_options(&tmp_opt);
1056 	tmp_opt.mss_clamp = IPV6_MIN_MTU - sizeof(struct tcphdr) - sizeof(struct ipv6hdr);
1057 	tmp_opt.user_mss = tp->rx_opt.user_mss;
1058 	tcp_parse_options(skb, &tmp_opt, &hash_location, 0);
1059 
1060 	if (tmp_opt.cookie_plus > 0 &&
1061 	    tmp_opt.saw_tstamp &&
1062 	    !tp->rx_opt.cookie_out_never &&
1063 	    (sysctl_tcp_cookie_size > 0 ||
1064 	     (tp->cookie_values != NULL &&
1065 	      tp->cookie_values->cookie_desired > 0))) {
1066 		u8 *c;
1067 		u32 *d;
1068 		u32 *mess = &tmp_ext.cookie_bakery[COOKIE_DIGEST_WORDS];
1069 		int l = tmp_opt.cookie_plus - TCPOLEN_COOKIE_BASE;
1070 
1071 		if (tcp_cookie_generator(&tmp_ext.cookie_bakery[0]) != 0)
1072 			goto drop_and_free;
1073 
1074 		/* Secret recipe starts with IP addresses */
1075 		d = (__force u32 *)&ipv6_hdr(skb)->daddr.s6_addr32[0];
1076 		*mess++ ^= *d++;
1077 		*mess++ ^= *d++;
1078 		*mess++ ^= *d++;
1079 		*mess++ ^= *d++;
1080 		d = (__force u32 *)&ipv6_hdr(skb)->saddr.s6_addr32[0];
1081 		*mess++ ^= *d++;
1082 		*mess++ ^= *d++;
1083 		*mess++ ^= *d++;
1084 		*mess++ ^= *d++;
1085 
1086 		/* plus variable length Initiator Cookie */
1087 		c = (u8 *)mess;
1088 		while (l-- > 0)
1089 			*c++ ^= *hash_location++;
1090 
1091 		want_cookie = false;	/* not our kind of cookie */
1092 		tmp_ext.cookie_out_never = 0; /* false */
1093 		tmp_ext.cookie_plus = tmp_opt.cookie_plus;
1094 	} else if (!tp->rx_opt.cookie_in_always) {
1095 		/* redundant indications, but ensure initialization. */
1096 		tmp_ext.cookie_out_never = 1; /* true */
1097 		tmp_ext.cookie_plus = 0;
1098 	} else {
1099 		goto drop_and_free;
1100 	}
1101 	tmp_ext.cookie_in_always = tp->rx_opt.cookie_in_always;
1102 
1103 	if (want_cookie && !tmp_opt.saw_tstamp)
1104 		tcp_clear_options(&tmp_opt);
1105 
1106 	tmp_opt.tstamp_ok = tmp_opt.saw_tstamp;
1107 	tcp_openreq_init(req, &tmp_opt, skb);
1108 
1109 	treq = inet6_rsk(req);
1110 	treq->rmt_addr = ipv6_hdr(skb)->saddr;
1111 	treq->loc_addr = ipv6_hdr(skb)->daddr;
1112 	if (!want_cookie || tmp_opt.tstamp_ok)
1113 		TCP_ECN_create_request(req, skb);
1114 
1115 	treq->iif = sk->sk_bound_dev_if;
1116 
1117 	/* So that link locals have meaning */
1118 	if (!sk->sk_bound_dev_if &&
1119 	    ipv6_addr_type(&treq->rmt_addr) & IPV6_ADDR_LINKLOCAL)
1120 		treq->iif = inet6_iif(skb);
1121 
1122 	if (!isn) {
1123 		if (ipv6_opt_accepted(sk, skb) ||
1124 		    np->rxopt.bits.rxinfo || np->rxopt.bits.rxoinfo ||
1125 		    np->rxopt.bits.rxhlim || np->rxopt.bits.rxohlim) {
1126 			atomic_inc(&skb->users);
1127 			treq->pktopts = skb;
1128 		}
1129 
1130 		if (want_cookie) {
1131 			isn = cookie_v6_init_sequence(sk, skb, &req->mss);
1132 			req->cookie_ts = tmp_opt.tstamp_ok;
1133 			goto have_isn;
1134 		}
1135 
1136 		/* VJ's idea. We save last timestamp seen
1137 		 * from the destination in peer table, when entering
1138 		 * state TIME-WAIT, and check against it before
1139 		 * accepting new connection request.
1140 		 *
1141 		 * If "isn" is not zero, this request hit alive
1142 		 * timewait bucket, so that all the necessary checks
1143 		 * are made in the function processing timewait state.
1144 		 */
1145 		if (tmp_opt.saw_tstamp &&
1146 		    tcp_death_row.sysctl_tw_recycle &&
1147 		    (dst = inet6_csk_route_req(sk, &fl6, req)) != NULL) {
1148 			if (!tcp_peer_is_proven(req, dst, true)) {
1149 				NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_PAWSPASSIVEREJECTED);
1150 				goto drop_and_release;
1151 			}
1152 		}
1153 		/* Kill the following clause, if you dislike this way. */
1154 		else if (!sysctl_tcp_syncookies &&
1155 			 (sysctl_max_syn_backlog - inet_csk_reqsk_queue_len(sk) <
1156 			  (sysctl_max_syn_backlog >> 2)) &&
1157 			 !tcp_peer_is_proven(req, dst, false)) {
1158 			/* Without syncookies last quarter of
1159 			 * backlog is filled with destinations,
1160 			 * proven to be alive.
1161 			 * It means that we continue to communicate
1162 			 * to destinations, already remembered
1163 			 * to the moment of synflood.
1164 			 */
1165 			LIMIT_NETDEBUG(KERN_DEBUG "TCP: drop open request from %pI6/%u\n",
1166 				       &treq->rmt_addr, ntohs(tcp_hdr(skb)->source));
1167 			goto drop_and_release;
1168 		}
1169 
1170 		isn = tcp_v6_init_sequence(skb);
1171 	}
1172 have_isn:
1173 	tcp_rsk(req)->snt_isn = isn;
1174 	tcp_rsk(req)->snt_synack = tcp_time_stamp;
1175 
1176 	if (security_inet_conn_request(sk, skb, req))
1177 		goto drop_and_release;
1178 
1179 	if (tcp_v6_send_synack(sk, dst, &fl6, req,
1180 			       (struct request_values *)&tmp_ext,
1181 			       skb_get_queue_mapping(skb)) ||
1182 	    want_cookie)
1183 		goto drop_and_free;
1184 
1185 	inet6_csk_reqsk_queue_hash_add(sk, req, TCP_TIMEOUT_INIT);
1186 	return 0;
1187 
1188 drop_and_release:
1189 	dst_release(dst);
1190 drop_and_free:
1191 	reqsk_free(req);
1192 drop:
1193 	return 0; /* don't send reset */
1194 }
1195 
1196 static struct sock * tcp_v6_syn_recv_sock(struct sock *sk, struct sk_buff *skb,
1197 					  struct request_sock *req,
1198 					  struct dst_entry *dst)
1199 {
1200 	struct inet6_request_sock *treq;
1201 	struct ipv6_pinfo *newnp, *np = inet6_sk(sk);
1202 	struct tcp6_sock *newtcp6sk;
1203 	struct inet_sock *newinet;
1204 	struct tcp_sock *newtp;
1205 	struct sock *newsk;
1206 #ifdef CONFIG_TCP_MD5SIG
1207 	struct tcp_md5sig_key *key;
1208 #endif
1209 	struct flowi6 fl6;
1210 
1211 	if (skb->protocol == htons(ETH_P_IP)) {
1212 		/*
1213 		 *	v6 mapped
1214 		 */
1215 
1216 		newsk = tcp_v4_syn_recv_sock(sk, skb, req, dst);
1217 
1218 		if (newsk == NULL)
1219 			return NULL;
1220 
1221 		newtcp6sk = (struct tcp6_sock *)newsk;
1222 		inet_sk(newsk)->pinet6 = &newtcp6sk->inet6;
1223 
1224 		newinet = inet_sk(newsk);
1225 		newnp = inet6_sk(newsk);
1226 		newtp = tcp_sk(newsk);
1227 
1228 		memcpy(newnp, np, sizeof(struct ipv6_pinfo));
1229 
1230 		ipv6_addr_set_v4mapped(newinet->inet_daddr, &newnp->daddr);
1231 
1232 		ipv6_addr_set_v4mapped(newinet->inet_saddr, &newnp->saddr);
1233 
1234 		newnp->rcv_saddr = newnp->saddr;
1235 
1236 		inet_csk(newsk)->icsk_af_ops = &ipv6_mapped;
1237 		newsk->sk_backlog_rcv = tcp_v4_do_rcv;
1238 #ifdef CONFIG_TCP_MD5SIG
1239 		newtp->af_specific = &tcp_sock_ipv6_mapped_specific;
1240 #endif
1241 
1242 		newnp->ipv6_ac_list = NULL;
1243 		newnp->ipv6_fl_list = NULL;
1244 		newnp->pktoptions  = NULL;
1245 		newnp->opt	   = NULL;
1246 		newnp->mcast_oif   = inet6_iif(skb);
1247 		newnp->mcast_hops  = ipv6_hdr(skb)->hop_limit;
1248 		newnp->rcv_tclass  = ipv6_tclass(ipv6_hdr(skb));
1249 
1250 		/*
1251 		 * No need to charge this sock to the relevant IPv6 refcnt debug socks count
1252 		 * here, tcp_create_openreq_child now does this for us, see the comment in
1253 		 * that function for the gory details. -acme
1254 		 */
1255 
1256 		/* It is tricky place. Until this moment IPv4 tcp
1257 		   worked with IPv6 icsk.icsk_af_ops.
1258 		   Sync it now.
1259 		 */
1260 		tcp_sync_mss(newsk, inet_csk(newsk)->icsk_pmtu_cookie);
1261 
1262 		return newsk;
1263 	}
1264 
1265 	treq = inet6_rsk(req);
1266 
1267 	if (sk_acceptq_is_full(sk))
1268 		goto out_overflow;
1269 
1270 	if (!dst) {
1271 		dst = inet6_csk_route_req(sk, &fl6, req);
1272 		if (!dst)
1273 			goto out;
1274 	}
1275 
1276 	newsk = tcp_create_openreq_child(sk, req, skb);
1277 	if (newsk == NULL)
1278 		goto out_nonewsk;
1279 
1280 	/*
1281 	 * No need to charge this sock to the relevant IPv6 refcnt debug socks
1282 	 * count here, tcp_create_openreq_child now does this for us, see the
1283 	 * comment in that function for the gory details. -acme
1284 	 */
1285 
1286 	newsk->sk_gso_type = SKB_GSO_TCPV6;
1287 	__ip6_dst_store(newsk, dst, NULL, NULL);
1288 
1289 	newtcp6sk = (struct tcp6_sock *)newsk;
1290 	inet_sk(newsk)->pinet6 = &newtcp6sk->inet6;
1291 
1292 	newtp = tcp_sk(newsk);
1293 	newinet = inet_sk(newsk);
1294 	newnp = inet6_sk(newsk);
1295 
1296 	memcpy(newnp, np, sizeof(struct ipv6_pinfo));
1297 
1298 	newnp->daddr = treq->rmt_addr;
1299 	newnp->saddr = treq->loc_addr;
1300 	newnp->rcv_saddr = treq->loc_addr;
1301 	newsk->sk_bound_dev_if = treq->iif;
1302 
1303 	/* Now IPv6 options...
1304 
1305 	   First: no IPv4 options.
1306 	 */
1307 	newinet->inet_opt = NULL;
1308 	newnp->ipv6_ac_list = NULL;
1309 	newnp->ipv6_fl_list = NULL;
1310 
1311 	/* Clone RX bits */
1312 	newnp->rxopt.all = np->rxopt.all;
1313 
1314 	/* Clone pktoptions received with SYN */
1315 	newnp->pktoptions = NULL;
1316 	if (treq->pktopts != NULL) {
1317 		newnp->pktoptions = skb_clone(treq->pktopts, GFP_ATOMIC);
1318 		consume_skb(treq->pktopts);
1319 		treq->pktopts = NULL;
1320 		if (newnp->pktoptions)
1321 			skb_set_owner_r(newnp->pktoptions, newsk);
1322 	}
1323 	newnp->opt	  = NULL;
1324 	newnp->mcast_oif  = inet6_iif(skb);
1325 	newnp->mcast_hops = ipv6_hdr(skb)->hop_limit;
1326 	newnp->rcv_tclass = ipv6_tclass(ipv6_hdr(skb));
1327 
1328 	/* Clone native IPv6 options from listening socket (if any)
1329 
1330 	   Yes, keeping reference count would be much more clever,
1331 	   but we make one more one thing there: reattach optmem
1332 	   to newsk.
1333 	 */
1334 	if (np->opt)
1335 		newnp->opt = ipv6_dup_options(newsk, np->opt);
1336 
1337 	inet_csk(newsk)->icsk_ext_hdr_len = 0;
1338 	if (newnp->opt)
1339 		inet_csk(newsk)->icsk_ext_hdr_len = (newnp->opt->opt_nflen +
1340 						     newnp->opt->opt_flen);
1341 
1342 	tcp_mtup_init(newsk);
1343 	tcp_sync_mss(newsk, dst_mtu(dst));
1344 	newtp->advmss = dst_metric_advmss(dst);
1345 	if (tcp_sk(sk)->rx_opt.user_mss &&
1346 	    tcp_sk(sk)->rx_opt.user_mss < newtp->advmss)
1347 		newtp->advmss = tcp_sk(sk)->rx_opt.user_mss;
1348 
1349 	tcp_initialize_rcv_mss(newsk);
1350 	if (tcp_rsk(req)->snt_synack)
1351 		tcp_valid_rtt_meas(newsk,
1352 		    tcp_time_stamp - tcp_rsk(req)->snt_synack);
1353 	newtp->total_retrans = req->retrans;
1354 
1355 	newinet->inet_daddr = newinet->inet_saddr = LOOPBACK4_IPV6;
1356 	newinet->inet_rcv_saddr = LOOPBACK4_IPV6;
1357 
1358 #ifdef CONFIG_TCP_MD5SIG
1359 	/* Copy over the MD5 key from the original socket */
1360 	if ((key = tcp_v6_md5_do_lookup(sk, &newnp->daddr)) != NULL) {
1361 		/* We're using one, so create a matching key
1362 		 * on the newsk structure. If we fail to get
1363 		 * memory, then we end up not copying the key
1364 		 * across. Shucks.
1365 		 */
1366 		tcp_md5_do_add(newsk, (union tcp_md5_addr *)&newnp->daddr,
1367 			       AF_INET6, key->key, key->keylen, GFP_ATOMIC);
1368 	}
1369 #endif
1370 
1371 	if (__inet_inherit_port(sk, newsk) < 0) {
1372 		sock_put(newsk);
1373 		goto out;
1374 	}
1375 	__inet6_hash(newsk, NULL);
1376 
1377 	return newsk;
1378 
1379 out_overflow:
1380 	NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
1381 out_nonewsk:
1382 	dst_release(dst);
1383 out:
1384 	NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
1385 	return NULL;
1386 }
1387 
1388 static __sum16 tcp_v6_checksum_init(struct sk_buff *skb)
1389 {
1390 	if (skb->ip_summed == CHECKSUM_COMPLETE) {
1391 		if (!tcp_v6_check(skb->len, &ipv6_hdr(skb)->saddr,
1392 				  &ipv6_hdr(skb)->daddr, skb->csum)) {
1393 			skb->ip_summed = CHECKSUM_UNNECESSARY;
1394 			return 0;
1395 		}
1396 	}
1397 
1398 	skb->csum = ~csum_unfold(tcp_v6_check(skb->len,
1399 					      &ipv6_hdr(skb)->saddr,
1400 					      &ipv6_hdr(skb)->daddr, 0));
1401 
1402 	if (skb->len <= 76) {
1403 		return __skb_checksum_complete(skb);
1404 	}
1405 	return 0;
1406 }
1407 
1408 /* The socket must have it's spinlock held when we get
1409  * here.
1410  *
1411  * We have a potential double-lock case here, so even when
1412  * doing backlog processing we use the BH locking scheme.
1413  * This is because we cannot sleep with the original spinlock
1414  * held.
1415  */
1416 static int tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb)
1417 {
1418 	struct ipv6_pinfo *np = inet6_sk(sk);
1419 	struct tcp_sock *tp;
1420 	struct sk_buff *opt_skb = NULL;
1421 
1422 	/* Imagine: socket is IPv6. IPv4 packet arrives,
1423 	   goes to IPv4 receive handler and backlogged.
1424 	   From backlog it always goes here. Kerboom...
1425 	   Fortunately, tcp_rcv_established and rcv_established
1426 	   handle them correctly, but it is not case with
1427 	   tcp_v6_hnd_req and tcp_v6_send_reset().   --ANK
1428 	 */
1429 
1430 	if (skb->protocol == htons(ETH_P_IP))
1431 		return tcp_v4_do_rcv(sk, skb);
1432 
1433 #ifdef CONFIG_TCP_MD5SIG
1434 	if (tcp_v6_inbound_md5_hash (sk, skb))
1435 		goto discard;
1436 #endif
1437 
1438 	if (sk_filter(sk, skb))
1439 		goto discard;
1440 
1441 	/*
1442 	 *	socket locking is here for SMP purposes as backlog rcv
1443 	 *	is currently called with bh processing disabled.
1444 	 */
1445 
1446 	/* Do Stevens' IPV6_PKTOPTIONS.
1447 
1448 	   Yes, guys, it is the only place in our code, where we
1449 	   may make it not affecting IPv4.
1450 	   The rest of code is protocol independent,
1451 	   and I do not like idea to uglify IPv4.
1452 
1453 	   Actually, all the idea behind IPV6_PKTOPTIONS
1454 	   looks not very well thought. For now we latch
1455 	   options, received in the last packet, enqueued
1456 	   by tcp. Feel free to propose better solution.
1457 					       --ANK (980728)
1458 	 */
1459 	if (np->rxopt.all)
1460 		opt_skb = skb_clone(skb, GFP_ATOMIC);
1461 
1462 	if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
1463 		sock_rps_save_rxhash(sk, skb);
1464 		if (tcp_rcv_established(sk, skb, tcp_hdr(skb), skb->len))
1465 			goto reset;
1466 		if (opt_skb)
1467 			goto ipv6_pktoptions;
1468 		return 0;
1469 	}
1470 
1471 	if (skb->len < tcp_hdrlen(skb) || tcp_checksum_complete(skb))
1472 		goto csum_err;
1473 
1474 	if (sk->sk_state == TCP_LISTEN) {
1475 		struct sock *nsk = tcp_v6_hnd_req(sk, skb);
1476 		if (!nsk)
1477 			goto discard;
1478 
1479 		/*
1480 		 * Queue it on the new socket if the new socket is active,
1481 		 * otherwise we just shortcircuit this and continue with
1482 		 * the new socket..
1483 		 */
1484 		if(nsk != sk) {
1485 			sock_rps_save_rxhash(nsk, skb);
1486 			if (tcp_child_process(sk, nsk, skb))
1487 				goto reset;
1488 			if (opt_skb)
1489 				__kfree_skb(opt_skb);
1490 			return 0;
1491 		}
1492 	} else
1493 		sock_rps_save_rxhash(sk, skb);
1494 
1495 	if (tcp_rcv_state_process(sk, skb, tcp_hdr(skb), skb->len))
1496 		goto reset;
1497 	if (opt_skb)
1498 		goto ipv6_pktoptions;
1499 	return 0;
1500 
1501 reset:
1502 	tcp_v6_send_reset(sk, skb);
1503 discard:
1504 	if (opt_skb)
1505 		__kfree_skb(opt_skb);
1506 	kfree_skb(skb);
1507 	return 0;
1508 csum_err:
1509 	TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_INERRS);
1510 	goto discard;
1511 
1512 
1513 ipv6_pktoptions:
1514 	/* Do you ask, what is it?
1515 
1516 	   1. skb was enqueued by tcp.
1517 	   2. skb is added to tail of read queue, rather than out of order.
1518 	   3. socket is not in passive state.
1519 	   4. Finally, it really contains options, which user wants to receive.
1520 	 */
1521 	tp = tcp_sk(sk);
1522 	if (TCP_SKB_CB(opt_skb)->end_seq == tp->rcv_nxt &&
1523 	    !((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN))) {
1524 		if (np->rxopt.bits.rxinfo || np->rxopt.bits.rxoinfo)
1525 			np->mcast_oif = inet6_iif(opt_skb);
1526 		if (np->rxopt.bits.rxhlim || np->rxopt.bits.rxohlim)
1527 			np->mcast_hops = ipv6_hdr(opt_skb)->hop_limit;
1528 		if (np->rxopt.bits.rxtclass)
1529 			np->rcv_tclass = ipv6_tclass(ipv6_hdr(skb));
1530 		if (ipv6_opt_accepted(sk, opt_skb)) {
1531 			skb_set_owner_r(opt_skb, sk);
1532 			opt_skb = xchg(&np->pktoptions, opt_skb);
1533 		} else {
1534 			__kfree_skb(opt_skb);
1535 			opt_skb = xchg(&np->pktoptions, NULL);
1536 		}
1537 	}
1538 
1539 	kfree_skb(opt_skb);
1540 	return 0;
1541 }
1542 
1543 static int tcp_v6_rcv(struct sk_buff *skb)
1544 {
1545 	const struct tcphdr *th;
1546 	const struct ipv6hdr *hdr;
1547 	struct sock *sk;
1548 	int ret;
1549 	struct net *net = dev_net(skb->dev);
1550 
1551 	if (skb->pkt_type != PACKET_HOST)
1552 		goto discard_it;
1553 
1554 	/*
1555 	 *	Count it even if it's bad.
1556 	 */
1557 	TCP_INC_STATS_BH(net, TCP_MIB_INSEGS);
1558 
1559 	if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
1560 		goto discard_it;
1561 
1562 	th = tcp_hdr(skb);
1563 
1564 	if (th->doff < sizeof(struct tcphdr)/4)
1565 		goto bad_packet;
1566 	if (!pskb_may_pull(skb, th->doff*4))
1567 		goto discard_it;
1568 
1569 	if (!skb_csum_unnecessary(skb) && tcp_v6_checksum_init(skb))
1570 		goto bad_packet;
1571 
1572 	th = tcp_hdr(skb);
1573 	hdr = ipv6_hdr(skb);
1574 	TCP_SKB_CB(skb)->seq = ntohl(th->seq);
1575 	TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
1576 				    skb->len - th->doff*4);
1577 	TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
1578 	TCP_SKB_CB(skb)->when = 0;
1579 	TCP_SKB_CB(skb)->ip_dsfield = ipv6_get_dsfield(hdr);
1580 	TCP_SKB_CB(skb)->sacked = 0;
1581 
1582 	sk = __inet6_lookup_skb(&tcp_hashinfo, skb, th->source, th->dest);
1583 	if (!sk)
1584 		goto no_tcp_socket;
1585 
1586 process:
1587 	if (sk->sk_state == TCP_TIME_WAIT)
1588 		goto do_time_wait;
1589 
1590 	if (hdr->hop_limit < inet6_sk(sk)->min_hopcount) {
1591 		NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP);
1592 		goto discard_and_relse;
1593 	}
1594 
1595 	if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb))
1596 		goto discard_and_relse;
1597 
1598 	if (sk_filter(sk, skb))
1599 		goto discard_and_relse;
1600 
1601 	skb->dev = NULL;
1602 
1603 	bh_lock_sock_nested(sk);
1604 	ret = 0;
1605 	if (!sock_owned_by_user(sk)) {
1606 #ifdef CONFIG_NET_DMA
1607 		struct tcp_sock *tp = tcp_sk(sk);
1608 		if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list)
1609 			tp->ucopy.dma_chan = net_dma_find_channel();
1610 		if (tp->ucopy.dma_chan)
1611 			ret = tcp_v6_do_rcv(sk, skb);
1612 		else
1613 #endif
1614 		{
1615 			if (!tcp_prequeue(sk, skb))
1616 				ret = tcp_v6_do_rcv(sk, skb);
1617 		}
1618 	} else if (unlikely(sk_add_backlog(sk, skb,
1619 					   sk->sk_rcvbuf + sk->sk_sndbuf))) {
1620 		bh_unlock_sock(sk);
1621 		NET_INC_STATS_BH(net, LINUX_MIB_TCPBACKLOGDROP);
1622 		goto discard_and_relse;
1623 	}
1624 	bh_unlock_sock(sk);
1625 
1626 	sock_put(sk);
1627 	return ret ? -1 : 0;
1628 
1629 no_tcp_socket:
1630 	if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb))
1631 		goto discard_it;
1632 
1633 	if (skb->len < (th->doff<<2) || tcp_checksum_complete(skb)) {
1634 bad_packet:
1635 		TCP_INC_STATS_BH(net, TCP_MIB_INERRS);
1636 	} else {
1637 		tcp_v6_send_reset(NULL, skb);
1638 	}
1639 
1640 discard_it:
1641 
1642 	/*
1643 	 *	Discard frame
1644 	 */
1645 
1646 	kfree_skb(skb);
1647 	return 0;
1648 
1649 discard_and_relse:
1650 	sock_put(sk);
1651 	goto discard_it;
1652 
1653 do_time_wait:
1654 	if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
1655 		inet_twsk_put(inet_twsk(sk));
1656 		goto discard_it;
1657 	}
1658 
1659 	if (skb->len < (th->doff<<2) || tcp_checksum_complete(skb)) {
1660 		TCP_INC_STATS_BH(net, TCP_MIB_INERRS);
1661 		inet_twsk_put(inet_twsk(sk));
1662 		goto discard_it;
1663 	}
1664 
1665 	switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) {
1666 	case TCP_TW_SYN:
1667 	{
1668 		struct sock *sk2;
1669 
1670 		sk2 = inet6_lookup_listener(dev_net(skb->dev), &tcp_hashinfo,
1671 					    &ipv6_hdr(skb)->daddr,
1672 					    ntohs(th->dest), inet6_iif(skb));
1673 		if (sk2 != NULL) {
1674 			struct inet_timewait_sock *tw = inet_twsk(sk);
1675 			inet_twsk_deschedule(tw, &tcp_death_row);
1676 			inet_twsk_put(tw);
1677 			sk = sk2;
1678 			goto process;
1679 		}
1680 		/* Fall through to ACK */
1681 	}
1682 	case TCP_TW_ACK:
1683 		tcp_v6_timewait_ack(sk, skb);
1684 		break;
1685 	case TCP_TW_RST:
1686 		goto no_tcp_socket;
1687 	case TCP_TW_SUCCESS:;
1688 	}
1689 	goto discard_it;
1690 }
1691 
1692 static struct timewait_sock_ops tcp6_timewait_sock_ops = {
1693 	.twsk_obj_size	= sizeof(struct tcp6_timewait_sock),
1694 	.twsk_unique	= tcp_twsk_unique,
1695 	.twsk_destructor= tcp_twsk_destructor,
1696 };
1697 
1698 static const struct inet_connection_sock_af_ops ipv6_specific = {
1699 	.queue_xmit	   = inet6_csk_xmit,
1700 	.send_check	   = tcp_v6_send_check,
1701 	.rebuild_header	   = inet6_sk_rebuild_header,
1702 	.conn_request	   = tcp_v6_conn_request,
1703 	.syn_recv_sock	   = tcp_v6_syn_recv_sock,
1704 	.net_header_len	   = sizeof(struct ipv6hdr),
1705 	.net_frag_header_len = sizeof(struct frag_hdr),
1706 	.setsockopt	   = ipv6_setsockopt,
1707 	.getsockopt	   = ipv6_getsockopt,
1708 	.addr2sockaddr	   = inet6_csk_addr2sockaddr,
1709 	.sockaddr_len	   = sizeof(struct sockaddr_in6),
1710 	.bind_conflict	   = inet6_csk_bind_conflict,
1711 #ifdef CONFIG_COMPAT
1712 	.compat_setsockopt = compat_ipv6_setsockopt,
1713 	.compat_getsockopt = compat_ipv6_getsockopt,
1714 #endif
1715 };
1716 
1717 #ifdef CONFIG_TCP_MD5SIG
1718 static const struct tcp_sock_af_ops tcp_sock_ipv6_specific = {
1719 	.md5_lookup	=	tcp_v6_md5_lookup,
1720 	.calc_md5_hash	=	tcp_v6_md5_hash_skb,
1721 	.md5_parse	=	tcp_v6_parse_md5_keys,
1722 };
1723 #endif
1724 
1725 /*
1726  *	TCP over IPv4 via INET6 API
1727  */
1728 
1729 static const struct inet_connection_sock_af_ops ipv6_mapped = {
1730 	.queue_xmit	   = ip_queue_xmit,
1731 	.send_check	   = tcp_v4_send_check,
1732 	.rebuild_header	   = inet_sk_rebuild_header,
1733 	.conn_request	   = tcp_v6_conn_request,
1734 	.syn_recv_sock	   = tcp_v6_syn_recv_sock,
1735 	.net_header_len	   = sizeof(struct iphdr),
1736 	.setsockopt	   = ipv6_setsockopt,
1737 	.getsockopt	   = ipv6_getsockopt,
1738 	.addr2sockaddr	   = inet6_csk_addr2sockaddr,
1739 	.sockaddr_len	   = sizeof(struct sockaddr_in6),
1740 	.bind_conflict	   = inet6_csk_bind_conflict,
1741 #ifdef CONFIG_COMPAT
1742 	.compat_setsockopt = compat_ipv6_setsockopt,
1743 	.compat_getsockopt = compat_ipv6_getsockopt,
1744 #endif
1745 };
1746 
1747 #ifdef CONFIG_TCP_MD5SIG
1748 static const struct tcp_sock_af_ops tcp_sock_ipv6_mapped_specific = {
1749 	.md5_lookup	=	tcp_v4_md5_lookup,
1750 	.calc_md5_hash	=	tcp_v4_md5_hash_skb,
1751 	.md5_parse	=	tcp_v6_parse_md5_keys,
1752 };
1753 #endif
1754 
1755 /* NOTE: A lot of things set to zero explicitly by call to
1756  *       sk_alloc() so need not be done here.
1757  */
1758 static int tcp_v6_init_sock(struct sock *sk)
1759 {
1760 	struct inet_connection_sock *icsk = inet_csk(sk);
1761 
1762 	tcp_init_sock(sk);
1763 
1764 	icsk->icsk_af_ops = &ipv6_specific;
1765 
1766 #ifdef CONFIG_TCP_MD5SIG
1767 	tcp_sk(sk)->af_specific = &tcp_sock_ipv6_specific;
1768 #endif
1769 
1770 	return 0;
1771 }
1772 
1773 static void tcp_v6_destroy_sock(struct sock *sk)
1774 {
1775 	tcp_v4_destroy_sock(sk);
1776 	inet6_destroy_sock(sk);
1777 }
1778 
1779 #ifdef CONFIG_PROC_FS
1780 /* Proc filesystem TCPv6 sock list dumping. */
1781 static void get_openreq6(struct seq_file *seq,
1782 			 const struct sock *sk, struct request_sock *req, int i, int uid)
1783 {
1784 	int ttd = req->expires - jiffies;
1785 	const struct in6_addr *src = &inet6_rsk(req)->loc_addr;
1786 	const struct in6_addr *dest = &inet6_rsk(req)->rmt_addr;
1787 
1788 	if (ttd < 0)
1789 		ttd = 0;
1790 
1791 	seq_printf(seq,
1792 		   "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
1793 		   "%02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK\n",
1794 		   i,
1795 		   src->s6_addr32[0], src->s6_addr32[1],
1796 		   src->s6_addr32[2], src->s6_addr32[3],
1797 		   ntohs(inet_rsk(req)->loc_port),
1798 		   dest->s6_addr32[0], dest->s6_addr32[1],
1799 		   dest->s6_addr32[2], dest->s6_addr32[3],
1800 		   ntohs(inet_rsk(req)->rmt_port),
1801 		   TCP_SYN_RECV,
1802 		   0,0, /* could print option size, but that is af dependent. */
1803 		   1,   /* timers active (only the expire timer) */
1804 		   jiffies_to_clock_t(ttd),
1805 		   req->retrans,
1806 		   uid,
1807 		   0,  /* non standard timer */
1808 		   0, /* open_requests have no inode */
1809 		   0, req);
1810 }
1811 
1812 static void get_tcp6_sock(struct seq_file *seq, struct sock *sp, int i)
1813 {
1814 	const struct in6_addr *dest, *src;
1815 	__u16 destp, srcp;
1816 	int timer_active;
1817 	unsigned long timer_expires;
1818 	const struct inet_sock *inet = inet_sk(sp);
1819 	const struct tcp_sock *tp = tcp_sk(sp);
1820 	const struct inet_connection_sock *icsk = inet_csk(sp);
1821 	const struct ipv6_pinfo *np = inet6_sk(sp);
1822 
1823 	dest  = &np->daddr;
1824 	src   = &np->rcv_saddr;
1825 	destp = ntohs(inet->inet_dport);
1826 	srcp  = ntohs(inet->inet_sport);
1827 
1828 	if (icsk->icsk_pending == ICSK_TIME_RETRANS) {
1829 		timer_active	= 1;
1830 		timer_expires	= icsk->icsk_timeout;
1831 	} else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
1832 		timer_active	= 4;
1833 		timer_expires	= icsk->icsk_timeout;
1834 	} else if (timer_pending(&sp->sk_timer)) {
1835 		timer_active	= 2;
1836 		timer_expires	= sp->sk_timer.expires;
1837 	} else {
1838 		timer_active	= 0;
1839 		timer_expires = jiffies;
1840 	}
1841 
1842 	seq_printf(seq,
1843 		   "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
1844 		   "%02X %08X:%08X %02X:%08lX %08X %5d %8d %lu %d %pK %lu %lu %u %u %d\n",
1845 		   i,
1846 		   src->s6_addr32[0], src->s6_addr32[1],
1847 		   src->s6_addr32[2], src->s6_addr32[3], srcp,
1848 		   dest->s6_addr32[0], dest->s6_addr32[1],
1849 		   dest->s6_addr32[2], dest->s6_addr32[3], destp,
1850 		   sp->sk_state,
1851 		   tp->write_seq-tp->snd_una,
1852 		   (sp->sk_state == TCP_LISTEN) ? sp->sk_ack_backlog : (tp->rcv_nxt - tp->copied_seq),
1853 		   timer_active,
1854 		   jiffies_to_clock_t(timer_expires - jiffies),
1855 		   icsk->icsk_retransmits,
1856 		   sock_i_uid(sp),
1857 		   icsk->icsk_probes_out,
1858 		   sock_i_ino(sp),
1859 		   atomic_read(&sp->sk_refcnt), sp,
1860 		   jiffies_to_clock_t(icsk->icsk_rto),
1861 		   jiffies_to_clock_t(icsk->icsk_ack.ato),
1862 		   (icsk->icsk_ack.quick << 1 ) | icsk->icsk_ack.pingpong,
1863 		   tp->snd_cwnd,
1864 		   tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh
1865 		   );
1866 }
1867 
1868 static void get_timewait6_sock(struct seq_file *seq,
1869 			       struct inet_timewait_sock *tw, int i)
1870 {
1871 	const struct in6_addr *dest, *src;
1872 	__u16 destp, srcp;
1873 	const struct inet6_timewait_sock *tw6 = inet6_twsk((struct sock *)tw);
1874 	int ttd = tw->tw_ttd - jiffies;
1875 
1876 	if (ttd < 0)
1877 		ttd = 0;
1878 
1879 	dest = &tw6->tw_v6_daddr;
1880 	src  = &tw6->tw_v6_rcv_saddr;
1881 	destp = ntohs(tw->tw_dport);
1882 	srcp  = ntohs(tw->tw_sport);
1883 
1884 	seq_printf(seq,
1885 		   "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
1886 		   "%02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK\n",
1887 		   i,
1888 		   src->s6_addr32[0], src->s6_addr32[1],
1889 		   src->s6_addr32[2], src->s6_addr32[3], srcp,
1890 		   dest->s6_addr32[0], dest->s6_addr32[1],
1891 		   dest->s6_addr32[2], dest->s6_addr32[3], destp,
1892 		   tw->tw_substate, 0, 0,
1893 		   3, jiffies_to_clock_t(ttd), 0, 0, 0, 0,
1894 		   atomic_read(&tw->tw_refcnt), tw);
1895 }
1896 
1897 static int tcp6_seq_show(struct seq_file *seq, void *v)
1898 {
1899 	struct tcp_iter_state *st;
1900 
1901 	if (v == SEQ_START_TOKEN) {
1902 		seq_puts(seq,
1903 			 "  sl  "
1904 			 "local_address                         "
1905 			 "remote_address                        "
1906 			 "st tx_queue rx_queue tr tm->when retrnsmt"
1907 			 "   uid  timeout inode\n");
1908 		goto out;
1909 	}
1910 	st = seq->private;
1911 
1912 	switch (st->state) {
1913 	case TCP_SEQ_STATE_LISTENING:
1914 	case TCP_SEQ_STATE_ESTABLISHED:
1915 		get_tcp6_sock(seq, v, st->num);
1916 		break;
1917 	case TCP_SEQ_STATE_OPENREQ:
1918 		get_openreq6(seq, st->syn_wait_sk, v, st->num, st->uid);
1919 		break;
1920 	case TCP_SEQ_STATE_TIME_WAIT:
1921 		get_timewait6_sock(seq, v, st->num);
1922 		break;
1923 	}
1924 out:
1925 	return 0;
1926 }
1927 
1928 static const struct file_operations tcp6_afinfo_seq_fops = {
1929 	.owner   = THIS_MODULE,
1930 	.open    = tcp_seq_open,
1931 	.read    = seq_read,
1932 	.llseek  = seq_lseek,
1933 	.release = seq_release_net
1934 };
1935 
1936 static struct tcp_seq_afinfo tcp6_seq_afinfo = {
1937 	.name		= "tcp6",
1938 	.family		= AF_INET6,
1939 	.seq_fops	= &tcp6_afinfo_seq_fops,
1940 	.seq_ops	= {
1941 		.show		= tcp6_seq_show,
1942 	},
1943 };
1944 
1945 int __net_init tcp6_proc_init(struct net *net)
1946 {
1947 	return tcp_proc_register(net, &tcp6_seq_afinfo);
1948 }
1949 
1950 void tcp6_proc_exit(struct net *net)
1951 {
1952 	tcp_proc_unregister(net, &tcp6_seq_afinfo);
1953 }
1954 #endif
1955 
1956 struct proto tcpv6_prot = {
1957 	.name			= "TCPv6",
1958 	.owner			= THIS_MODULE,
1959 	.close			= tcp_close,
1960 	.connect		= tcp_v6_connect,
1961 	.disconnect		= tcp_disconnect,
1962 	.accept			= inet_csk_accept,
1963 	.ioctl			= tcp_ioctl,
1964 	.init			= tcp_v6_init_sock,
1965 	.destroy		= tcp_v6_destroy_sock,
1966 	.shutdown		= tcp_shutdown,
1967 	.setsockopt		= tcp_setsockopt,
1968 	.getsockopt		= tcp_getsockopt,
1969 	.recvmsg		= tcp_recvmsg,
1970 	.sendmsg		= tcp_sendmsg,
1971 	.sendpage		= tcp_sendpage,
1972 	.backlog_rcv		= tcp_v6_do_rcv,
1973 	.release_cb		= tcp_release_cb,
1974 	.hash			= tcp_v6_hash,
1975 	.unhash			= inet_unhash,
1976 	.get_port		= inet_csk_get_port,
1977 	.enter_memory_pressure	= tcp_enter_memory_pressure,
1978 	.sockets_allocated	= &tcp_sockets_allocated,
1979 	.memory_allocated	= &tcp_memory_allocated,
1980 	.memory_pressure	= &tcp_memory_pressure,
1981 	.orphan_count		= &tcp_orphan_count,
1982 	.sysctl_wmem		= sysctl_tcp_wmem,
1983 	.sysctl_rmem		= sysctl_tcp_rmem,
1984 	.max_header		= MAX_TCP_HEADER,
1985 	.obj_size		= sizeof(struct tcp6_sock),
1986 	.slab_flags		= SLAB_DESTROY_BY_RCU,
1987 	.twsk_prot		= &tcp6_timewait_sock_ops,
1988 	.rsk_prot		= &tcp6_request_sock_ops,
1989 	.h.hashinfo		= &tcp_hashinfo,
1990 	.no_autobind		= true,
1991 #ifdef CONFIG_COMPAT
1992 	.compat_setsockopt	= compat_tcp_setsockopt,
1993 	.compat_getsockopt	= compat_tcp_getsockopt,
1994 #endif
1995 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM
1996 	.proto_cgroup		= tcp_proto_cgroup,
1997 #endif
1998 };
1999 
2000 static const struct inet6_protocol tcpv6_protocol = {
2001 	.handler	=	tcp_v6_rcv,
2002 	.err_handler	=	tcp_v6_err,
2003 	.gso_send_check	=	tcp_v6_gso_send_check,
2004 	.gso_segment	=	tcp_tso_segment,
2005 	.gro_receive	=	tcp6_gro_receive,
2006 	.gro_complete	=	tcp6_gro_complete,
2007 	.flags		=	INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
2008 };
2009 
2010 static struct inet_protosw tcpv6_protosw = {
2011 	.type		=	SOCK_STREAM,
2012 	.protocol	=	IPPROTO_TCP,
2013 	.prot		=	&tcpv6_prot,
2014 	.ops		=	&inet6_stream_ops,
2015 	.no_check	=	0,
2016 	.flags		=	INET_PROTOSW_PERMANENT |
2017 				INET_PROTOSW_ICSK,
2018 };
2019 
2020 static int __net_init tcpv6_net_init(struct net *net)
2021 {
2022 	return inet_ctl_sock_create(&net->ipv6.tcp_sk, PF_INET6,
2023 				    SOCK_RAW, IPPROTO_TCP, net);
2024 }
2025 
2026 static void __net_exit tcpv6_net_exit(struct net *net)
2027 {
2028 	inet_ctl_sock_destroy(net->ipv6.tcp_sk);
2029 }
2030 
2031 static void __net_exit tcpv6_net_exit_batch(struct list_head *net_exit_list)
2032 {
2033 	inet_twsk_purge(&tcp_hashinfo, &tcp_death_row, AF_INET6);
2034 }
2035 
2036 static struct pernet_operations tcpv6_net_ops = {
2037 	.init	    = tcpv6_net_init,
2038 	.exit	    = tcpv6_net_exit,
2039 	.exit_batch = tcpv6_net_exit_batch,
2040 };
2041 
2042 int __init tcpv6_init(void)
2043 {
2044 	int ret;
2045 
2046 	ret = inet6_add_protocol(&tcpv6_protocol, IPPROTO_TCP);
2047 	if (ret)
2048 		goto out;
2049 
2050 	/* register inet6 protocol */
2051 	ret = inet6_register_protosw(&tcpv6_protosw);
2052 	if (ret)
2053 		goto out_tcpv6_protocol;
2054 
2055 	ret = register_pernet_subsys(&tcpv6_net_ops);
2056 	if (ret)
2057 		goto out_tcpv6_protosw;
2058 out:
2059 	return ret;
2060 
2061 out_tcpv6_protocol:
2062 	inet6_del_protocol(&tcpv6_protocol, IPPROTO_TCP);
2063 out_tcpv6_protosw:
2064 	inet6_unregister_protosw(&tcpv6_protosw);
2065 	goto out;
2066 }
2067 
2068 void tcpv6_exit(void)
2069 {
2070 	unregister_pernet_subsys(&tcpv6_net_ops);
2071 	inet6_unregister_protosw(&tcpv6_protosw);
2072 	inet6_del_protocol(&tcpv6_protocol, IPPROTO_TCP);
2073 }
2074