ipv6: Consolidate route lookup sequences.
[linux-2.6.git] / net / ipv6 / tcp_ipv6.c
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
65 #include <asm/uaccess.h>
66
67 #include <linux/proc_fs.h>
68 #include <linux/seq_file.h>
69
70 #include <linux/crypto.h>
71 #include <linux/scatterlist.h>
72
73 static void     tcp_v6_send_reset(struct sock *sk, struct sk_buff *skb);
74 static void     tcp_v6_reqsk_send_ack(struct sock *sk, struct sk_buff *skb,
75                                       struct request_sock *req);
76
77 static int      tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb);
78 static void     __tcp_v6_send_check(struct sk_buff *skb,
79                                     struct in6_addr *saddr,
80                                     struct in6_addr *daddr);
81
82 static const struct inet_connection_sock_af_ops ipv6_mapped;
83 static const struct inet_connection_sock_af_ops ipv6_specific;
84 #ifdef CONFIG_TCP_MD5SIG
85 static const struct tcp_sock_af_ops tcp_sock_ipv6_specific;
86 static const struct tcp_sock_af_ops tcp_sock_ipv6_mapped_specific;
87 #else
88 static struct tcp_md5sig_key *tcp_v6_md5_do_lookup(struct sock *sk,
89                                                    struct in6_addr *addr)
90 {
91         return NULL;
92 }
93 #endif
94
95 static void tcp_v6_hash(struct sock *sk)
96 {
97         if (sk->sk_state != TCP_CLOSE) {
98                 if (inet_csk(sk)->icsk_af_ops == &ipv6_mapped) {
99                         tcp_prot.hash(sk);
100                         return;
101                 }
102                 local_bh_disable();
103                 __inet6_hash(sk, NULL);
104                 local_bh_enable();
105         }
106 }
107
108 static __inline__ __sum16 tcp_v6_check(int len,
109                                    struct in6_addr *saddr,
110                                    struct in6_addr *daddr,
111                                    __wsum base)
112 {
113         return csum_ipv6_magic(saddr, daddr, len, IPPROTO_TCP, base);
114 }
115
116 static __u32 tcp_v6_init_sequence(struct sk_buff *skb)
117 {
118         return secure_tcpv6_sequence_number(ipv6_hdr(skb)->daddr.s6_addr32,
119                                             ipv6_hdr(skb)->saddr.s6_addr32,
120                                             tcp_hdr(skb)->dest,
121                                             tcp_hdr(skb)->source);
122 }
123
124 static int tcp_v6_connect(struct sock *sk, struct sockaddr *uaddr,
125                           int addr_len)
126 {
127         struct sockaddr_in6 *usin = (struct sockaddr_in6 *) uaddr;
128         struct inet_sock *inet = inet_sk(sk);
129         struct inet_connection_sock *icsk = inet_csk(sk);
130         struct ipv6_pinfo *np = inet6_sk(sk);
131         struct tcp_sock *tp = tcp_sk(sk);
132         struct in6_addr *saddr = NULL, *final_p, final;
133         struct rt6_info *rt;
134         struct flowi fl;
135         struct dst_entry *dst;
136         int addr_type;
137         int err;
138
139         if (addr_len < SIN6_LEN_RFC2133)
140                 return -EINVAL;
141
142         if (usin->sin6_family != AF_INET6)
143                 return -EAFNOSUPPORT;
144
145         memset(&fl, 0, sizeof(fl));
146
147         if (np->sndflow) {
148                 fl.fl6_flowlabel = usin->sin6_flowinfo&IPV6_FLOWINFO_MASK;
149                 IP6_ECN_flow_init(fl.fl6_flowlabel);
150                 if (fl.fl6_flowlabel&IPV6_FLOWLABEL_MASK) {
151                         struct ip6_flowlabel *flowlabel;
152                         flowlabel = fl6_sock_lookup(sk, fl.fl6_flowlabel);
153                         if (flowlabel == NULL)
154                                 return -EINVAL;
155                         ipv6_addr_copy(&usin->sin6_addr, &flowlabel->dst);
156                         fl6_sock_release(flowlabel);
157                 }
158         }
159
160         /*
161          *      connect() to INADDR_ANY means loopback (BSD'ism).
162          */
163
164         if(ipv6_addr_any(&usin->sin6_addr))
165                 usin->sin6_addr.s6_addr[15] = 0x1;
166
167         addr_type = ipv6_addr_type(&usin->sin6_addr);
168
169         if(addr_type & IPV6_ADDR_MULTICAST)
170                 return -ENETUNREACH;
171
172         if (addr_type&IPV6_ADDR_LINKLOCAL) {
173                 if (addr_len >= sizeof(struct sockaddr_in6) &&
174                     usin->sin6_scope_id) {
175                         /* If interface is set while binding, indices
176                          * must coincide.
177                          */
178                         if (sk->sk_bound_dev_if &&
179                             sk->sk_bound_dev_if != usin->sin6_scope_id)
180                                 return -EINVAL;
181
182                         sk->sk_bound_dev_if = usin->sin6_scope_id;
183                 }
184
185                 /* Connect to link-local address requires an interface */
186                 if (!sk->sk_bound_dev_if)
187                         return -EINVAL;
188         }
189
190         if (tp->rx_opt.ts_recent_stamp &&
191             !ipv6_addr_equal(&np->daddr, &usin->sin6_addr)) {
192                 tp->rx_opt.ts_recent = 0;
193                 tp->rx_opt.ts_recent_stamp = 0;
194                 tp->write_seq = 0;
195         }
196
197         ipv6_addr_copy(&np->daddr, &usin->sin6_addr);
198         np->flow_label = fl.fl6_flowlabel;
199
200         /*
201          *      TCP over IPv4
202          */
203
204         if (addr_type == IPV6_ADDR_MAPPED) {
205                 u32 exthdrlen = icsk->icsk_ext_hdr_len;
206                 struct sockaddr_in sin;
207
208                 SOCK_DEBUG(sk, "connect: ipv4 mapped\n");
209
210                 if (__ipv6_only_sock(sk))
211                         return -ENETUNREACH;
212
213                 sin.sin_family = AF_INET;
214                 sin.sin_port = usin->sin6_port;
215                 sin.sin_addr.s_addr = usin->sin6_addr.s6_addr32[3];
216
217                 icsk->icsk_af_ops = &ipv6_mapped;
218                 sk->sk_backlog_rcv = tcp_v4_do_rcv;
219 #ifdef CONFIG_TCP_MD5SIG
220                 tp->af_specific = &tcp_sock_ipv6_mapped_specific;
221 #endif
222
223                 err = tcp_v4_connect(sk, (struct sockaddr *)&sin, sizeof(sin));
224
225                 if (err) {
226                         icsk->icsk_ext_hdr_len = exthdrlen;
227                         icsk->icsk_af_ops = &ipv6_specific;
228                         sk->sk_backlog_rcv = tcp_v6_do_rcv;
229 #ifdef CONFIG_TCP_MD5SIG
230                         tp->af_specific = &tcp_sock_ipv6_specific;
231 #endif
232                         goto failure;
233                 } else {
234                         ipv6_addr_set_v4mapped(inet->inet_saddr, &np->saddr);
235                         ipv6_addr_set_v4mapped(inet->inet_rcv_saddr,
236                                                &np->rcv_saddr);
237                 }
238
239                 return err;
240         }
241
242         if (!ipv6_addr_any(&np->rcv_saddr))
243                 saddr = &np->rcv_saddr;
244
245         fl.proto = IPPROTO_TCP;
246         ipv6_addr_copy(&fl.fl6_dst, &np->daddr);
247         ipv6_addr_copy(&fl.fl6_src,
248                        (saddr ? saddr : &np->saddr));
249         fl.oif = sk->sk_bound_dev_if;
250         fl.mark = sk->sk_mark;
251         fl.fl_ip_dport = usin->sin6_port;
252         fl.fl_ip_sport = inet->inet_sport;
253
254         final_p = fl6_update_dst(&fl, np->opt, &final);
255
256         security_sk_classify_flow(sk, &fl);
257
258         dst = ip6_dst_lookup_flow(sk, &fl, final_p, true);
259         if (IS_ERR(dst)) {
260                 err = PTR_ERR(dst);
261                 goto failure;
262         }
263
264         if (saddr == NULL) {
265                 saddr = &fl.fl6_src;
266                 ipv6_addr_copy(&np->rcv_saddr, saddr);
267         }
268
269         /* set the source address */
270         ipv6_addr_copy(&np->saddr, saddr);
271         inet->inet_rcv_saddr = LOOPBACK4_IPV6;
272
273         sk->sk_gso_type = SKB_GSO_TCPV6;
274         __ip6_dst_store(sk, dst, NULL, NULL);
275
276         rt = (struct rt6_info *) dst;
277         if (tcp_death_row.sysctl_tw_recycle &&
278             !tp->rx_opt.ts_recent_stamp &&
279             ipv6_addr_equal(&rt->rt6i_dst.addr, &np->daddr)) {
280                 struct inet_peer *peer = rt6_get_peer(rt);
281                 /*
282                  * VJ's idea. We save last timestamp seen from
283                  * the destination in peer table, when entering state
284                  * TIME-WAIT * and initialize rx_opt.ts_recent from it,
285                  * when trying new connection.
286                  */
287                 if (peer) {
288                         inet_peer_refcheck(peer);
289                         if ((u32)get_seconds() - peer->tcp_ts_stamp <= TCP_PAWS_MSL) {
290                                 tp->rx_opt.ts_recent_stamp = peer->tcp_ts_stamp;
291                                 tp->rx_opt.ts_recent = peer->tcp_ts;
292                         }
293                 }
294         }
295
296         icsk->icsk_ext_hdr_len = 0;
297         if (np->opt)
298                 icsk->icsk_ext_hdr_len = (np->opt->opt_flen +
299                                           np->opt->opt_nflen);
300
301         tp->rx_opt.mss_clamp = IPV6_MIN_MTU - sizeof(struct tcphdr) - sizeof(struct ipv6hdr);
302
303         inet->inet_dport = usin->sin6_port;
304
305         tcp_set_state(sk, TCP_SYN_SENT);
306         err = inet6_hash_connect(&tcp_death_row, sk);
307         if (err)
308                 goto late_failure;
309
310         if (!tp->write_seq)
311                 tp->write_seq = secure_tcpv6_sequence_number(np->saddr.s6_addr32,
312                                                              np->daddr.s6_addr32,
313                                                              inet->inet_sport,
314                                                              inet->inet_dport);
315
316         err = tcp_connect(sk);
317         if (err)
318                 goto late_failure;
319
320         return 0;
321
322 late_failure:
323         tcp_set_state(sk, TCP_CLOSE);
324         __sk_dst_reset(sk);
325 failure:
326         inet->inet_dport = 0;
327         sk->sk_route_caps = 0;
328         return err;
329 }
330
331 static void tcp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
332                 u8 type, u8 code, int offset, __be32 info)
333 {
334         struct ipv6hdr *hdr = (struct ipv6hdr*)skb->data;
335         const struct tcphdr *th = (struct tcphdr *)(skb->data+offset);
336         struct ipv6_pinfo *np;
337         struct sock *sk;
338         int err;
339         struct tcp_sock *tp;
340         __u32 seq;
341         struct net *net = dev_net(skb->dev);
342
343         sk = inet6_lookup(net, &tcp_hashinfo, &hdr->daddr,
344                         th->dest, &hdr->saddr, th->source, skb->dev->ifindex);
345
346         if (sk == NULL) {
347                 ICMP6_INC_STATS_BH(net, __in6_dev_get(skb->dev),
348                                    ICMP6_MIB_INERRORS);
349                 return;
350         }
351
352         if (sk->sk_state == TCP_TIME_WAIT) {
353                 inet_twsk_put(inet_twsk(sk));
354                 return;
355         }
356
357         bh_lock_sock(sk);
358         if (sock_owned_by_user(sk))
359                 NET_INC_STATS_BH(net, LINUX_MIB_LOCKDROPPEDICMPS);
360
361         if (sk->sk_state == TCP_CLOSE)
362                 goto out;
363
364         if (ipv6_hdr(skb)->hop_limit < inet6_sk(sk)->min_hopcount) {
365                 NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP);
366                 goto out;
367         }
368
369         tp = tcp_sk(sk);
370         seq = ntohl(th->seq);
371         if (sk->sk_state != TCP_LISTEN &&
372             !between(seq, tp->snd_una, tp->snd_nxt)) {
373                 NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
374                 goto out;
375         }
376
377         np = inet6_sk(sk);
378
379         if (type == ICMPV6_PKT_TOOBIG) {
380                 struct dst_entry *dst;
381
382                 if (sock_owned_by_user(sk))
383                         goto out;
384                 if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE))
385                         goto out;
386
387                 /* icmp should have updated the destination cache entry */
388                 dst = __sk_dst_check(sk, np->dst_cookie);
389
390                 if (dst == NULL) {
391                         struct inet_sock *inet = inet_sk(sk);
392                         struct flowi fl;
393
394                         /* BUGGG_FUTURE: Again, it is not clear how
395                            to handle rthdr case. Ignore this complexity
396                            for now.
397                          */
398                         memset(&fl, 0, sizeof(fl));
399                         fl.proto = IPPROTO_TCP;
400                         ipv6_addr_copy(&fl.fl6_dst, &np->daddr);
401                         ipv6_addr_copy(&fl.fl6_src, &np->saddr);
402                         fl.oif = sk->sk_bound_dev_if;
403                         fl.mark = sk->sk_mark;
404                         fl.fl_ip_dport = inet->inet_dport;
405                         fl.fl_ip_sport = inet->inet_sport;
406                         security_skb_classify_flow(skb, &fl);
407
408                         dst = ip6_dst_lookup_flow(sk, &fl, NULL, false);
409                         if (IS_ERR(dst)) {
410                                 sk->sk_err_soft = -PTR_ERR(dst);
411                                 goto out;
412                         }
413
414                 } else
415                         dst_hold(dst);
416
417                 if (inet_csk(sk)->icsk_pmtu_cookie > dst_mtu(dst)) {
418                         tcp_sync_mss(sk, dst_mtu(dst));
419                         tcp_simple_retransmit(sk);
420                 } /* else let the usual retransmit timer handle it */
421                 dst_release(dst);
422                 goto out;
423         }
424
425         icmpv6_err_convert(type, code, &err);
426
427         /* Might be for an request_sock */
428         switch (sk->sk_state) {
429                 struct request_sock *req, **prev;
430         case TCP_LISTEN:
431                 if (sock_owned_by_user(sk))
432                         goto out;
433
434                 req = inet6_csk_search_req(sk, &prev, th->dest, &hdr->daddr,
435                                            &hdr->saddr, inet6_iif(skb));
436                 if (!req)
437                         goto out;
438
439                 /* ICMPs are not backlogged, hence we cannot get
440                  * an established socket here.
441                  */
442                 WARN_ON(req->sk != NULL);
443
444                 if (seq != tcp_rsk(req)->snt_isn) {
445                         NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
446                         goto out;
447                 }
448
449                 inet_csk_reqsk_queue_drop(sk, req, prev);
450                 goto out;
451
452         case TCP_SYN_SENT:
453         case TCP_SYN_RECV:  /* Cannot happen.
454                                It can, it SYNs are crossed. --ANK */
455                 if (!sock_owned_by_user(sk)) {
456                         sk->sk_err = err;
457                         sk->sk_error_report(sk);                /* Wake people up to see the error (see connect in sock.c) */
458
459                         tcp_done(sk);
460                 } else
461                         sk->sk_err_soft = err;
462                 goto out;
463         }
464
465         if (!sock_owned_by_user(sk) && np->recverr) {
466                 sk->sk_err = err;
467                 sk->sk_error_report(sk);
468         } else
469                 sk->sk_err_soft = err;
470
471 out:
472         bh_unlock_sock(sk);
473         sock_put(sk);
474 }
475
476
477 static int tcp_v6_send_synack(struct sock *sk, struct request_sock *req,
478                               struct request_values *rvp)
479 {
480         struct inet6_request_sock *treq = inet6_rsk(req);
481         struct ipv6_pinfo *np = inet6_sk(sk);
482         struct sk_buff * skb;
483         struct ipv6_txoptions *opt = NULL;
484         struct in6_addr * final_p, final;
485         struct flowi fl;
486         struct dst_entry *dst;
487         int err;
488
489         memset(&fl, 0, sizeof(fl));
490         fl.proto = IPPROTO_TCP;
491         ipv6_addr_copy(&fl.fl6_dst, &treq->rmt_addr);
492         ipv6_addr_copy(&fl.fl6_src, &treq->loc_addr);
493         fl.fl6_flowlabel = 0;
494         fl.oif = treq->iif;
495         fl.mark = sk->sk_mark;
496         fl.fl_ip_dport = inet_rsk(req)->rmt_port;
497         fl.fl_ip_sport = inet_rsk(req)->loc_port;
498         security_req_classify_flow(req, &fl);
499
500         opt = np->opt;
501         final_p = fl6_update_dst(&fl, opt, &final);
502
503         dst = ip6_dst_lookup_flow(sk, &fl, final_p, false);
504         if (IS_ERR(dst)) {
505                 err = PTR_ERR(dst);
506                 goto done;
507         }
508         skb = tcp_make_synack(sk, dst, req, rvp);
509         err = -ENOMEM;
510         if (skb) {
511                 __tcp_v6_send_check(skb, &treq->loc_addr, &treq->rmt_addr);
512
513                 ipv6_addr_copy(&fl.fl6_dst, &treq->rmt_addr);
514                 err = ip6_xmit(sk, skb, &fl, opt);
515                 err = net_xmit_eval(err);
516         }
517
518 done:
519         if (opt && opt != np->opt)
520                 sock_kfree_s(sk, opt, opt->tot_len);
521         dst_release(dst);
522         return err;
523 }
524
525 static int tcp_v6_rtx_synack(struct sock *sk, struct request_sock *req,
526                              struct request_values *rvp)
527 {
528         TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_RETRANSSEGS);
529         return tcp_v6_send_synack(sk, req, rvp);
530 }
531
532 static inline void syn_flood_warning(struct sk_buff *skb)
533 {
534 #ifdef CONFIG_SYN_COOKIES
535         if (sysctl_tcp_syncookies)
536                 printk(KERN_INFO
537                        "TCPv6: Possible SYN flooding on port %d. "
538                        "Sending cookies.\n", ntohs(tcp_hdr(skb)->dest));
539         else
540 #endif
541                 printk(KERN_INFO
542                        "TCPv6: Possible SYN flooding on port %d. "
543                        "Dropping request.\n", ntohs(tcp_hdr(skb)->dest));
544 }
545
546 static void tcp_v6_reqsk_destructor(struct request_sock *req)
547 {
548         kfree_skb(inet6_rsk(req)->pktopts);
549 }
550
551 #ifdef CONFIG_TCP_MD5SIG
552 static struct tcp_md5sig_key *tcp_v6_md5_do_lookup(struct sock *sk,
553                                                    struct in6_addr *addr)
554 {
555         struct tcp_sock *tp = tcp_sk(sk);
556         int i;
557
558         BUG_ON(tp == NULL);
559
560         if (!tp->md5sig_info || !tp->md5sig_info->entries6)
561                 return NULL;
562
563         for (i = 0; i < tp->md5sig_info->entries6; i++) {
564                 if (ipv6_addr_equal(&tp->md5sig_info->keys6[i].addr, addr))
565                         return &tp->md5sig_info->keys6[i].base;
566         }
567         return NULL;
568 }
569
570 static struct tcp_md5sig_key *tcp_v6_md5_lookup(struct sock *sk,
571                                                 struct sock *addr_sk)
572 {
573         return tcp_v6_md5_do_lookup(sk, &inet6_sk(addr_sk)->daddr);
574 }
575
576 static struct tcp_md5sig_key *tcp_v6_reqsk_md5_lookup(struct sock *sk,
577                                                       struct request_sock *req)
578 {
579         return tcp_v6_md5_do_lookup(sk, &inet6_rsk(req)->rmt_addr);
580 }
581
582 static int tcp_v6_md5_do_add(struct sock *sk, struct in6_addr *peer,
583                              char *newkey, u8 newkeylen)
584 {
585         /* Add key to the list */
586         struct tcp_md5sig_key *key;
587         struct tcp_sock *tp = tcp_sk(sk);
588         struct tcp6_md5sig_key *keys;
589
590         key = tcp_v6_md5_do_lookup(sk, peer);
591         if (key) {
592                 /* modify existing entry - just update that one */
593                 kfree(key->key);
594                 key->key = newkey;
595                 key->keylen = newkeylen;
596         } else {
597                 /* reallocate new list if current one is full. */
598                 if (!tp->md5sig_info) {
599                         tp->md5sig_info = kzalloc(sizeof(*tp->md5sig_info), GFP_ATOMIC);
600                         if (!tp->md5sig_info) {
601                                 kfree(newkey);
602                                 return -ENOMEM;
603                         }
604                         sk_nocaps_add(sk, NETIF_F_GSO_MASK);
605                 }
606                 if (tcp_alloc_md5sig_pool(sk) == NULL) {
607                         kfree(newkey);
608                         return -ENOMEM;
609                 }
610                 if (tp->md5sig_info->alloced6 == tp->md5sig_info->entries6) {
611                         keys = kmalloc((sizeof (tp->md5sig_info->keys6[0]) *
612                                        (tp->md5sig_info->entries6 + 1)), GFP_ATOMIC);
613
614                         if (!keys) {
615                                 tcp_free_md5sig_pool();
616                                 kfree(newkey);
617                                 return -ENOMEM;
618                         }
619
620                         if (tp->md5sig_info->entries6)
621                                 memmove(keys, tp->md5sig_info->keys6,
622                                         (sizeof (tp->md5sig_info->keys6[0]) *
623                                          tp->md5sig_info->entries6));
624
625                         kfree(tp->md5sig_info->keys6);
626                         tp->md5sig_info->keys6 = keys;
627                         tp->md5sig_info->alloced6++;
628                 }
629
630                 ipv6_addr_copy(&tp->md5sig_info->keys6[tp->md5sig_info->entries6].addr,
631                                peer);
632                 tp->md5sig_info->keys6[tp->md5sig_info->entries6].base.key = newkey;
633                 tp->md5sig_info->keys6[tp->md5sig_info->entries6].base.keylen = newkeylen;
634
635                 tp->md5sig_info->entries6++;
636         }
637         return 0;
638 }
639
640 static int tcp_v6_md5_add_func(struct sock *sk, struct sock *addr_sk,
641                                u8 *newkey, __u8 newkeylen)
642 {
643         return tcp_v6_md5_do_add(sk, &inet6_sk(addr_sk)->daddr,
644                                  newkey, newkeylen);
645 }
646
647 static int tcp_v6_md5_do_del(struct sock *sk, struct in6_addr *peer)
648 {
649         struct tcp_sock *tp = tcp_sk(sk);
650         int i;
651
652         for (i = 0; i < tp->md5sig_info->entries6; i++) {
653                 if (ipv6_addr_equal(&tp->md5sig_info->keys6[i].addr, peer)) {
654                         /* Free the key */
655                         kfree(tp->md5sig_info->keys6[i].base.key);
656                         tp->md5sig_info->entries6--;
657
658                         if (tp->md5sig_info->entries6 == 0) {
659                                 kfree(tp->md5sig_info->keys6);
660                                 tp->md5sig_info->keys6 = NULL;
661                                 tp->md5sig_info->alloced6 = 0;
662                         } else {
663                                 /* shrink the database */
664                                 if (tp->md5sig_info->entries6 != i)
665                                         memmove(&tp->md5sig_info->keys6[i],
666                                                 &tp->md5sig_info->keys6[i+1],
667                                                 (tp->md5sig_info->entries6 - i)
668                                                 * sizeof (tp->md5sig_info->keys6[0]));
669                         }
670                         tcp_free_md5sig_pool();
671                         return 0;
672                 }
673         }
674         return -ENOENT;
675 }
676
677 static void tcp_v6_clear_md5_list (struct sock *sk)
678 {
679         struct tcp_sock *tp = tcp_sk(sk);
680         int i;
681
682         if (tp->md5sig_info->entries6) {
683                 for (i = 0; i < tp->md5sig_info->entries6; i++)
684                         kfree(tp->md5sig_info->keys6[i].base.key);
685                 tp->md5sig_info->entries6 = 0;
686                 tcp_free_md5sig_pool();
687         }
688
689         kfree(tp->md5sig_info->keys6);
690         tp->md5sig_info->keys6 = NULL;
691         tp->md5sig_info->alloced6 = 0;
692
693         if (tp->md5sig_info->entries4) {
694                 for (i = 0; i < tp->md5sig_info->entries4; i++)
695                         kfree(tp->md5sig_info->keys4[i].base.key);
696                 tp->md5sig_info->entries4 = 0;
697                 tcp_free_md5sig_pool();
698         }
699
700         kfree(tp->md5sig_info->keys4);
701         tp->md5sig_info->keys4 = NULL;
702         tp->md5sig_info->alloced4 = 0;
703 }
704
705 static int tcp_v6_parse_md5_keys (struct sock *sk, char __user *optval,
706                                   int optlen)
707 {
708         struct tcp_md5sig cmd;
709         struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)&cmd.tcpm_addr;
710         u8 *newkey;
711
712         if (optlen < sizeof(cmd))
713                 return -EINVAL;
714
715         if (copy_from_user(&cmd, optval, sizeof(cmd)))
716                 return -EFAULT;
717
718         if (sin6->sin6_family != AF_INET6)
719                 return -EINVAL;
720
721         if (!cmd.tcpm_keylen) {
722                 if (!tcp_sk(sk)->md5sig_info)
723                         return -ENOENT;
724                 if (ipv6_addr_v4mapped(&sin6->sin6_addr))
725                         return tcp_v4_md5_do_del(sk, sin6->sin6_addr.s6_addr32[3]);
726                 return tcp_v6_md5_do_del(sk, &sin6->sin6_addr);
727         }
728
729         if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN)
730                 return -EINVAL;
731
732         if (!tcp_sk(sk)->md5sig_info) {
733                 struct tcp_sock *tp = tcp_sk(sk);
734                 struct tcp_md5sig_info *p;
735
736                 p = kzalloc(sizeof(struct tcp_md5sig_info), GFP_KERNEL);
737                 if (!p)
738                         return -ENOMEM;
739
740                 tp->md5sig_info = p;
741                 sk_nocaps_add(sk, NETIF_F_GSO_MASK);
742         }
743
744         newkey = kmemdup(cmd.tcpm_key, cmd.tcpm_keylen, GFP_KERNEL);
745         if (!newkey)
746                 return -ENOMEM;
747         if (ipv6_addr_v4mapped(&sin6->sin6_addr)) {
748                 return tcp_v4_md5_do_add(sk, sin6->sin6_addr.s6_addr32[3],
749                                          newkey, cmd.tcpm_keylen);
750         }
751         return tcp_v6_md5_do_add(sk, &sin6->sin6_addr, newkey, cmd.tcpm_keylen);
752 }
753
754 static int tcp_v6_md5_hash_pseudoheader(struct tcp_md5sig_pool *hp,
755                                         struct in6_addr *daddr,
756                                         struct in6_addr *saddr, int nbytes)
757 {
758         struct tcp6_pseudohdr *bp;
759         struct scatterlist sg;
760
761         bp = &hp->md5_blk.ip6;
762         /* 1. TCP pseudo-header (RFC2460) */
763         ipv6_addr_copy(&bp->saddr, saddr);
764         ipv6_addr_copy(&bp->daddr, daddr);
765         bp->protocol = cpu_to_be32(IPPROTO_TCP);
766         bp->len = cpu_to_be32(nbytes);
767
768         sg_init_one(&sg, bp, sizeof(*bp));
769         return crypto_hash_update(&hp->md5_desc, &sg, sizeof(*bp));
770 }
771
772 static int tcp_v6_md5_hash_hdr(char *md5_hash, struct tcp_md5sig_key *key,
773                                struct in6_addr *daddr, struct in6_addr *saddr,
774                                struct tcphdr *th)
775 {
776         struct tcp_md5sig_pool *hp;
777         struct hash_desc *desc;
778
779         hp = tcp_get_md5sig_pool();
780         if (!hp)
781                 goto clear_hash_noput;
782         desc = &hp->md5_desc;
783
784         if (crypto_hash_init(desc))
785                 goto clear_hash;
786         if (tcp_v6_md5_hash_pseudoheader(hp, daddr, saddr, th->doff << 2))
787                 goto clear_hash;
788         if (tcp_md5_hash_header(hp, th))
789                 goto clear_hash;
790         if (tcp_md5_hash_key(hp, key))
791                 goto clear_hash;
792         if (crypto_hash_final(desc, md5_hash))
793                 goto clear_hash;
794
795         tcp_put_md5sig_pool();
796         return 0;
797
798 clear_hash:
799         tcp_put_md5sig_pool();
800 clear_hash_noput:
801         memset(md5_hash, 0, 16);
802         return 1;
803 }
804
805 static int tcp_v6_md5_hash_skb(char *md5_hash, struct tcp_md5sig_key *key,
806                                struct sock *sk, struct request_sock *req,
807                                struct sk_buff *skb)
808 {
809         struct in6_addr *saddr, *daddr;
810         struct tcp_md5sig_pool *hp;
811         struct hash_desc *desc;
812         struct tcphdr *th = tcp_hdr(skb);
813
814         if (sk) {
815                 saddr = &inet6_sk(sk)->saddr;
816                 daddr = &inet6_sk(sk)->daddr;
817         } else if (req) {
818                 saddr = &inet6_rsk(req)->loc_addr;
819                 daddr = &inet6_rsk(req)->rmt_addr;
820         } else {
821                 struct ipv6hdr *ip6h = ipv6_hdr(skb);
822                 saddr = &ip6h->saddr;
823                 daddr = &ip6h->daddr;
824         }
825
826         hp = tcp_get_md5sig_pool();
827         if (!hp)
828                 goto clear_hash_noput;
829         desc = &hp->md5_desc;
830
831         if (crypto_hash_init(desc))
832                 goto clear_hash;
833
834         if (tcp_v6_md5_hash_pseudoheader(hp, daddr, saddr, skb->len))
835                 goto clear_hash;
836         if (tcp_md5_hash_header(hp, th))
837                 goto clear_hash;
838         if (tcp_md5_hash_skb_data(hp, skb, th->doff << 2))
839                 goto clear_hash;
840         if (tcp_md5_hash_key(hp, key))
841                 goto clear_hash;
842         if (crypto_hash_final(desc, md5_hash))
843                 goto clear_hash;
844
845         tcp_put_md5sig_pool();
846         return 0;
847
848 clear_hash:
849         tcp_put_md5sig_pool();
850 clear_hash_noput:
851         memset(md5_hash, 0, 16);
852         return 1;
853 }
854
855 static int tcp_v6_inbound_md5_hash (struct sock *sk, struct sk_buff *skb)
856 {
857         __u8 *hash_location = NULL;
858         struct tcp_md5sig_key *hash_expected;
859         struct ipv6hdr *ip6h = ipv6_hdr(skb);
860         struct tcphdr *th = tcp_hdr(skb);
861         int genhash;
862         u8 newhash[16];
863
864         hash_expected = tcp_v6_md5_do_lookup(sk, &ip6h->saddr);
865         hash_location = tcp_parse_md5sig_option(th);
866
867         /* We've parsed the options - do we have a hash? */
868         if (!hash_expected && !hash_location)
869                 return 0;
870
871         if (hash_expected && !hash_location) {
872                 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5NOTFOUND);
873                 return 1;
874         }
875
876         if (!hash_expected && hash_location) {
877                 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5UNEXPECTED);
878                 return 1;
879         }
880
881         /* check the signature */
882         genhash = tcp_v6_md5_hash_skb(newhash,
883                                       hash_expected,
884                                       NULL, NULL, skb);
885
886         if (genhash || memcmp(hash_location, newhash, 16) != 0) {
887                 if (net_ratelimit()) {
888                         printk(KERN_INFO "MD5 Hash %s for [%pI6c]:%u->[%pI6c]:%u\n",
889                                genhash ? "failed" : "mismatch",
890                                &ip6h->saddr, ntohs(th->source),
891                                &ip6h->daddr, ntohs(th->dest));
892                 }
893                 return 1;
894         }
895         return 0;
896 }
897 #endif
898
899 struct request_sock_ops tcp6_request_sock_ops __read_mostly = {
900         .family         =       AF_INET6,
901         .obj_size       =       sizeof(struct tcp6_request_sock),
902         .rtx_syn_ack    =       tcp_v6_rtx_synack,
903         .send_ack       =       tcp_v6_reqsk_send_ack,
904         .destructor     =       tcp_v6_reqsk_destructor,
905         .send_reset     =       tcp_v6_send_reset,
906         .syn_ack_timeout =      tcp_syn_ack_timeout,
907 };
908
909 #ifdef CONFIG_TCP_MD5SIG
910 static const struct tcp_request_sock_ops tcp_request_sock_ipv6_ops = {
911         .md5_lookup     =       tcp_v6_reqsk_md5_lookup,
912         .calc_md5_hash  =       tcp_v6_md5_hash_skb,
913 };
914 #endif
915
916 static void __tcp_v6_send_check(struct sk_buff *skb,
917                                 struct in6_addr *saddr, struct in6_addr *daddr)
918 {
919         struct tcphdr *th = tcp_hdr(skb);
920
921         if (skb->ip_summed == CHECKSUM_PARTIAL) {
922                 th->check = ~tcp_v6_check(skb->len, saddr, daddr, 0);
923                 skb->csum_start = skb_transport_header(skb) - skb->head;
924                 skb->csum_offset = offsetof(struct tcphdr, check);
925         } else {
926                 th->check = tcp_v6_check(skb->len, saddr, daddr,
927                                          csum_partial(th, th->doff << 2,
928                                                       skb->csum));
929         }
930 }
931
932 static void tcp_v6_send_check(struct sock *sk, struct sk_buff *skb)
933 {
934         struct ipv6_pinfo *np = inet6_sk(sk);
935
936         __tcp_v6_send_check(skb, &np->saddr, &np->daddr);
937 }
938
939 static int tcp_v6_gso_send_check(struct sk_buff *skb)
940 {
941         struct ipv6hdr *ipv6h;
942         struct tcphdr *th;
943
944         if (!pskb_may_pull(skb, sizeof(*th)))
945                 return -EINVAL;
946
947         ipv6h = ipv6_hdr(skb);
948         th = tcp_hdr(skb);
949
950         th->check = 0;
951         skb->ip_summed = CHECKSUM_PARTIAL;
952         __tcp_v6_send_check(skb, &ipv6h->saddr, &ipv6h->daddr);
953         return 0;
954 }
955
956 static struct sk_buff **tcp6_gro_receive(struct sk_buff **head,
957                                          struct sk_buff *skb)
958 {
959         struct ipv6hdr *iph = skb_gro_network_header(skb);
960
961         switch (skb->ip_summed) {
962         case CHECKSUM_COMPLETE:
963                 if (!tcp_v6_check(skb_gro_len(skb), &iph->saddr, &iph->daddr,
964                                   skb->csum)) {
965                         skb->ip_summed = CHECKSUM_UNNECESSARY;
966                         break;
967                 }
968
969                 /* fall through */
970         case CHECKSUM_NONE:
971                 NAPI_GRO_CB(skb)->flush = 1;
972                 return NULL;
973         }
974
975         return tcp_gro_receive(head, skb);
976 }
977
978 static int tcp6_gro_complete(struct sk_buff *skb)
979 {
980         struct ipv6hdr *iph = ipv6_hdr(skb);
981         struct tcphdr *th = tcp_hdr(skb);
982
983         th->check = ~tcp_v6_check(skb->len - skb_transport_offset(skb),
984                                   &iph->saddr, &iph->daddr, 0);
985         skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
986
987         return tcp_gro_complete(skb);
988 }
989
990 static void tcp_v6_send_response(struct sk_buff *skb, u32 seq, u32 ack, u32 win,
991                                  u32 ts, struct tcp_md5sig_key *key, int rst)
992 {
993         struct tcphdr *th = tcp_hdr(skb), *t1;
994         struct sk_buff *buff;
995         struct flowi fl;
996         struct net *net = dev_net(skb_dst(skb)->dev);
997         struct sock *ctl_sk = net->ipv6.tcp_sk;
998         unsigned int tot_len = sizeof(struct tcphdr);
999         struct dst_entry *dst;
1000         __be32 *topt;
1001
1002         if (ts)
1003                 tot_len += TCPOLEN_TSTAMP_ALIGNED;
1004 #ifdef CONFIG_TCP_MD5SIG
1005         if (key)
1006                 tot_len += TCPOLEN_MD5SIG_ALIGNED;
1007 #endif
1008
1009         buff = alloc_skb(MAX_HEADER + sizeof(struct ipv6hdr) + tot_len,
1010                          GFP_ATOMIC);
1011         if (buff == NULL)
1012                 return;
1013
1014         skb_reserve(buff, MAX_HEADER + sizeof(struct ipv6hdr) + tot_len);
1015
1016         t1 = (struct tcphdr *) skb_push(buff, tot_len);
1017         skb_reset_transport_header(buff);
1018
1019         /* Swap the send and the receive. */
1020         memset(t1, 0, sizeof(*t1));
1021         t1->dest = th->source;
1022         t1->source = th->dest;
1023         t1->doff = tot_len / 4;
1024         t1->seq = htonl(seq);
1025         t1->ack_seq = htonl(ack);
1026         t1->ack = !rst || !th->ack;
1027         t1->rst = rst;
1028         t1->window = htons(win);
1029
1030         topt = (__be32 *)(t1 + 1);
1031
1032         if (ts) {
1033                 *topt++ = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
1034                                 (TCPOPT_TIMESTAMP << 8) | TCPOLEN_TIMESTAMP);
1035                 *topt++ = htonl(tcp_time_stamp);
1036                 *topt++ = htonl(ts);
1037         }
1038
1039 #ifdef CONFIG_TCP_MD5SIG
1040         if (key) {
1041                 *topt++ = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
1042                                 (TCPOPT_MD5SIG << 8) | TCPOLEN_MD5SIG);
1043                 tcp_v6_md5_hash_hdr((__u8 *)topt, key,
1044                                     &ipv6_hdr(skb)->saddr,
1045                                     &ipv6_hdr(skb)->daddr, t1);
1046         }
1047 #endif
1048
1049         memset(&fl, 0, sizeof(fl));
1050         ipv6_addr_copy(&fl.fl6_dst, &ipv6_hdr(skb)->saddr);
1051         ipv6_addr_copy(&fl.fl6_src, &ipv6_hdr(skb)->daddr);
1052
1053         buff->ip_summed = CHECKSUM_PARTIAL;
1054         buff->csum = 0;
1055
1056         __tcp_v6_send_check(buff, &fl.fl6_src, &fl.fl6_dst);
1057
1058         fl.proto = IPPROTO_TCP;
1059         fl.oif = inet6_iif(skb);
1060         fl.fl_ip_dport = t1->dest;
1061         fl.fl_ip_sport = t1->source;
1062         security_skb_classify_flow(skb, &fl);
1063
1064         /* Pass a socket to ip6_dst_lookup either it is for RST
1065          * Underlying function will use this to retrieve the network
1066          * namespace
1067          */
1068         dst = ip6_dst_lookup_flow(ctl_sk, &fl, NULL, false);
1069         if (!IS_ERR(dst)) {
1070                 skb_dst_set(buff, dst);
1071                 ip6_xmit(ctl_sk, buff, &fl, NULL);
1072                 TCP_INC_STATS_BH(net, TCP_MIB_OUTSEGS);
1073                 if (rst)
1074                         TCP_INC_STATS_BH(net, TCP_MIB_OUTRSTS);
1075                 return;
1076         }
1077
1078         kfree_skb(buff);
1079 }
1080
1081 static void tcp_v6_send_reset(struct sock *sk, struct sk_buff *skb)
1082 {
1083         struct tcphdr *th = tcp_hdr(skb);
1084         u32 seq = 0, ack_seq = 0;
1085         struct tcp_md5sig_key *key = NULL;
1086
1087         if (th->rst)
1088                 return;
1089
1090         if (!ipv6_unicast_destination(skb))
1091                 return;
1092
1093 #ifdef CONFIG_TCP_MD5SIG
1094         if (sk)
1095                 key = tcp_v6_md5_do_lookup(sk, &ipv6_hdr(skb)->daddr);
1096 #endif
1097
1098         if (th->ack)
1099                 seq = ntohl(th->ack_seq);
1100         else
1101                 ack_seq = ntohl(th->seq) + th->syn + th->fin + skb->len -
1102                           (th->doff << 2);
1103
1104         tcp_v6_send_response(skb, seq, ack_seq, 0, 0, key, 1);
1105 }
1106
1107 static void tcp_v6_send_ack(struct sk_buff *skb, u32 seq, u32 ack, u32 win, u32 ts,
1108                             struct tcp_md5sig_key *key)
1109 {
1110         tcp_v6_send_response(skb, seq, ack, win, ts, key, 0);
1111 }
1112
1113 static void tcp_v6_timewait_ack(struct sock *sk, struct sk_buff *skb)
1114 {
1115         struct inet_timewait_sock *tw = inet_twsk(sk);
1116         struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
1117
1118         tcp_v6_send_ack(skb, tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
1119                         tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
1120                         tcptw->tw_ts_recent, tcp_twsk_md5_key(tcptw));
1121
1122         inet_twsk_put(tw);
1123 }
1124
1125 static void tcp_v6_reqsk_send_ack(struct sock *sk, struct sk_buff *skb,
1126                                   struct request_sock *req)
1127 {
1128         tcp_v6_send_ack(skb, tcp_rsk(req)->snt_isn + 1, tcp_rsk(req)->rcv_isn + 1, req->rcv_wnd, req->ts_recent,
1129                         tcp_v6_md5_do_lookup(sk, &ipv6_hdr(skb)->daddr));
1130 }
1131
1132
1133 static struct sock *tcp_v6_hnd_req(struct sock *sk,struct sk_buff *skb)
1134 {
1135         struct request_sock *req, **prev;
1136         const struct tcphdr *th = tcp_hdr(skb);
1137         struct sock *nsk;
1138
1139         /* Find possible connection requests. */
1140         req = inet6_csk_search_req(sk, &prev, th->source,
1141                                    &ipv6_hdr(skb)->saddr,
1142                                    &ipv6_hdr(skb)->daddr, inet6_iif(skb));
1143         if (req)
1144                 return tcp_check_req(sk, skb, req, prev);
1145
1146         nsk = __inet6_lookup_established(sock_net(sk), &tcp_hashinfo,
1147                         &ipv6_hdr(skb)->saddr, th->source,
1148                         &ipv6_hdr(skb)->daddr, ntohs(th->dest), inet6_iif(skb));
1149
1150         if (nsk) {
1151                 if (nsk->sk_state != TCP_TIME_WAIT) {
1152                         bh_lock_sock(nsk);
1153                         return nsk;
1154                 }
1155                 inet_twsk_put(inet_twsk(nsk));
1156                 return NULL;
1157         }
1158
1159 #ifdef CONFIG_SYN_COOKIES
1160         if (!th->syn)
1161                 sk = cookie_v6_check(sk, skb);
1162 #endif
1163         return sk;
1164 }
1165
1166 /* FIXME: this is substantially similar to the ipv4 code.
1167  * Can some kind of merge be done? -- erics
1168  */
1169 static int tcp_v6_conn_request(struct sock *sk, struct sk_buff *skb)
1170 {
1171         struct tcp_extend_values tmp_ext;
1172         struct tcp_options_received tmp_opt;
1173         u8 *hash_location;
1174         struct request_sock *req;
1175         struct inet6_request_sock *treq;
1176         struct ipv6_pinfo *np = inet6_sk(sk);
1177         struct tcp_sock *tp = tcp_sk(sk);
1178         __u32 isn = TCP_SKB_CB(skb)->when;
1179         struct dst_entry *dst = NULL;
1180 #ifdef CONFIG_SYN_COOKIES
1181         int want_cookie = 0;
1182 #else
1183 #define want_cookie 0
1184 #endif
1185
1186         if (skb->protocol == htons(ETH_P_IP))
1187                 return tcp_v4_conn_request(sk, skb);
1188
1189         if (!ipv6_unicast_destination(skb))
1190                 goto drop;
1191
1192         if (inet_csk_reqsk_queue_is_full(sk) && !isn) {
1193                 if (net_ratelimit())
1194                         syn_flood_warning(skb);
1195 #ifdef CONFIG_SYN_COOKIES
1196                 if (sysctl_tcp_syncookies)
1197                         want_cookie = 1;
1198                 else
1199 #endif
1200                 goto drop;
1201         }
1202
1203         if (sk_acceptq_is_full(sk) && inet_csk_reqsk_queue_young(sk) > 1)
1204                 goto drop;
1205
1206         req = inet6_reqsk_alloc(&tcp6_request_sock_ops);
1207         if (req == NULL)
1208                 goto drop;
1209
1210 #ifdef CONFIG_TCP_MD5SIG
1211         tcp_rsk(req)->af_specific = &tcp_request_sock_ipv6_ops;
1212 #endif
1213
1214         tcp_clear_options(&tmp_opt);
1215         tmp_opt.mss_clamp = IPV6_MIN_MTU - sizeof(struct tcphdr) - sizeof(struct ipv6hdr);
1216         tmp_opt.user_mss = tp->rx_opt.user_mss;
1217         tcp_parse_options(skb, &tmp_opt, &hash_location, 0);
1218
1219         if (tmp_opt.cookie_plus > 0 &&
1220             tmp_opt.saw_tstamp &&
1221             !tp->rx_opt.cookie_out_never &&
1222             (sysctl_tcp_cookie_size > 0 ||
1223              (tp->cookie_values != NULL &&
1224               tp->cookie_values->cookie_desired > 0))) {
1225                 u8 *c;
1226                 u32 *d;
1227                 u32 *mess = &tmp_ext.cookie_bakery[COOKIE_DIGEST_WORDS];
1228                 int l = tmp_opt.cookie_plus - TCPOLEN_COOKIE_BASE;
1229
1230                 if (tcp_cookie_generator(&tmp_ext.cookie_bakery[0]) != 0)
1231                         goto drop_and_free;
1232
1233                 /* Secret recipe starts with IP addresses */
1234                 d = (__force u32 *)&ipv6_hdr(skb)->daddr.s6_addr32[0];
1235                 *mess++ ^= *d++;
1236                 *mess++ ^= *d++;
1237                 *mess++ ^= *d++;
1238                 *mess++ ^= *d++;
1239                 d = (__force u32 *)&ipv6_hdr(skb)->saddr.s6_addr32[0];
1240                 *mess++ ^= *d++;
1241                 *mess++ ^= *d++;
1242                 *mess++ ^= *d++;
1243                 *mess++ ^= *d++;
1244
1245                 /* plus variable length Initiator Cookie */
1246                 c = (u8 *)mess;
1247                 while (l-- > 0)
1248                         *c++ ^= *hash_location++;
1249
1250 #ifdef CONFIG_SYN_COOKIES
1251                 want_cookie = 0;        /* not our kind of cookie */
1252 #endif
1253                 tmp_ext.cookie_out_never = 0; /* false */
1254                 tmp_ext.cookie_plus = tmp_opt.cookie_plus;
1255         } else if (!tp->rx_opt.cookie_in_always) {
1256                 /* redundant indications, but ensure initialization. */
1257                 tmp_ext.cookie_out_never = 1; /* true */
1258                 tmp_ext.cookie_plus = 0;
1259         } else {
1260                 goto drop_and_free;
1261         }
1262         tmp_ext.cookie_in_always = tp->rx_opt.cookie_in_always;
1263
1264         if (want_cookie && !tmp_opt.saw_tstamp)
1265                 tcp_clear_options(&tmp_opt);
1266
1267         tmp_opt.tstamp_ok = tmp_opt.saw_tstamp;
1268         tcp_openreq_init(req, &tmp_opt, skb);
1269
1270         treq = inet6_rsk(req);
1271         ipv6_addr_copy(&treq->rmt_addr, &ipv6_hdr(skb)->saddr);
1272         ipv6_addr_copy(&treq->loc_addr, &ipv6_hdr(skb)->daddr);
1273         if (!want_cookie || tmp_opt.tstamp_ok)
1274                 TCP_ECN_create_request(req, tcp_hdr(skb));
1275
1276         if (!isn) {
1277                 struct inet_peer *peer = NULL;
1278
1279                 if (ipv6_opt_accepted(sk, skb) ||
1280                     np->rxopt.bits.rxinfo || np->rxopt.bits.rxoinfo ||
1281                     np->rxopt.bits.rxhlim || np->rxopt.bits.rxohlim) {
1282                         atomic_inc(&skb->users);
1283                         treq->pktopts = skb;
1284                 }
1285                 treq->iif = sk->sk_bound_dev_if;
1286
1287                 /* So that link locals have meaning */
1288                 if (!sk->sk_bound_dev_if &&
1289                     ipv6_addr_type(&treq->rmt_addr) & IPV6_ADDR_LINKLOCAL)
1290                         treq->iif = inet6_iif(skb);
1291
1292                 if (want_cookie) {
1293                         isn = cookie_v6_init_sequence(sk, skb, &req->mss);
1294                         req->cookie_ts = tmp_opt.tstamp_ok;
1295                         goto have_isn;
1296                 }
1297
1298                 /* VJ's idea. We save last timestamp seen
1299                  * from the destination in peer table, when entering
1300                  * state TIME-WAIT, and check against it before
1301                  * accepting new connection request.
1302                  *
1303                  * If "isn" is not zero, this request hit alive
1304                  * timewait bucket, so that all the necessary checks
1305                  * are made in the function processing timewait state.
1306                  */
1307                 if (tmp_opt.saw_tstamp &&
1308                     tcp_death_row.sysctl_tw_recycle &&
1309                     (dst = inet6_csk_route_req(sk, req)) != NULL &&
1310                     (peer = rt6_get_peer((struct rt6_info *)dst)) != NULL &&
1311                     ipv6_addr_equal((struct in6_addr *)peer->daddr.addr.a6,
1312                                     &treq->rmt_addr)) {
1313                         inet_peer_refcheck(peer);
1314                         if ((u32)get_seconds() - peer->tcp_ts_stamp < TCP_PAWS_MSL &&
1315                             (s32)(peer->tcp_ts - req->ts_recent) >
1316                                                         TCP_PAWS_WINDOW) {
1317                                 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_PAWSPASSIVEREJECTED);
1318                                 goto drop_and_release;
1319                         }
1320                 }
1321                 /* Kill the following clause, if you dislike this way. */
1322                 else if (!sysctl_tcp_syncookies &&
1323                          (sysctl_max_syn_backlog - inet_csk_reqsk_queue_len(sk) <
1324                           (sysctl_max_syn_backlog >> 2)) &&
1325                          (!peer || !peer->tcp_ts_stamp) &&
1326                          (!dst || !dst_metric(dst, RTAX_RTT))) {
1327                         /* Without syncookies last quarter of
1328                          * backlog is filled with destinations,
1329                          * proven to be alive.
1330                          * It means that we continue to communicate
1331                          * to destinations, already remembered
1332                          * to the moment of synflood.
1333                          */
1334                         LIMIT_NETDEBUG(KERN_DEBUG "TCP: drop open request from %pI6/%u\n",
1335                                        &treq->rmt_addr, ntohs(tcp_hdr(skb)->source));
1336                         goto drop_and_release;
1337                 }
1338
1339                 isn = tcp_v6_init_sequence(skb);
1340         }
1341 have_isn:
1342         tcp_rsk(req)->snt_isn = isn;
1343
1344         security_inet_conn_request(sk, skb, req);
1345
1346         if (tcp_v6_send_synack(sk, req,
1347                                (struct request_values *)&tmp_ext) ||
1348             want_cookie)
1349                 goto drop_and_free;
1350
1351         inet6_csk_reqsk_queue_hash_add(sk, req, TCP_TIMEOUT_INIT);
1352         return 0;
1353
1354 drop_and_release:
1355         dst_release(dst);
1356 drop_and_free:
1357         reqsk_free(req);
1358 drop:
1359         return 0; /* don't send reset */
1360 }
1361
1362 static struct sock * tcp_v6_syn_recv_sock(struct sock *sk, struct sk_buff *skb,
1363                                           struct request_sock *req,
1364                                           struct dst_entry *dst)
1365 {
1366         struct inet6_request_sock *treq;
1367         struct ipv6_pinfo *newnp, *np = inet6_sk(sk);
1368         struct tcp6_sock *newtcp6sk;
1369         struct inet_sock *newinet;
1370         struct tcp_sock *newtp;
1371         struct sock *newsk;
1372         struct ipv6_txoptions *opt;
1373 #ifdef CONFIG_TCP_MD5SIG
1374         struct tcp_md5sig_key *key;
1375 #endif
1376
1377         if (skb->protocol == htons(ETH_P_IP)) {
1378                 /*
1379                  *      v6 mapped
1380                  */
1381
1382                 newsk = tcp_v4_syn_recv_sock(sk, skb, req, dst);
1383
1384                 if (newsk == NULL)
1385                         return NULL;
1386
1387                 newtcp6sk = (struct tcp6_sock *)newsk;
1388                 inet_sk(newsk)->pinet6 = &newtcp6sk->inet6;
1389
1390                 newinet = inet_sk(newsk);
1391                 newnp = inet6_sk(newsk);
1392                 newtp = tcp_sk(newsk);
1393
1394                 memcpy(newnp, np, sizeof(struct ipv6_pinfo));
1395
1396                 ipv6_addr_set_v4mapped(newinet->inet_daddr, &newnp->daddr);
1397
1398                 ipv6_addr_set_v4mapped(newinet->inet_saddr, &newnp->saddr);
1399
1400                 ipv6_addr_copy(&newnp->rcv_saddr, &newnp->saddr);
1401
1402                 inet_csk(newsk)->icsk_af_ops = &ipv6_mapped;
1403                 newsk->sk_backlog_rcv = tcp_v4_do_rcv;
1404 #ifdef CONFIG_TCP_MD5SIG
1405                 newtp->af_specific = &tcp_sock_ipv6_mapped_specific;
1406 #endif
1407
1408                 newnp->pktoptions  = NULL;
1409                 newnp->opt         = NULL;
1410                 newnp->mcast_oif   = inet6_iif(skb);
1411                 newnp->mcast_hops  = ipv6_hdr(skb)->hop_limit;
1412
1413                 /*
1414                  * No need to charge this sock to the relevant IPv6 refcnt debug socks count
1415                  * here, tcp_create_openreq_child now does this for us, see the comment in
1416                  * that function for the gory details. -acme
1417                  */
1418
1419                 /* It is tricky place. Until this moment IPv4 tcp
1420                    worked with IPv6 icsk.icsk_af_ops.
1421                    Sync it now.
1422                  */
1423                 tcp_sync_mss(newsk, inet_csk(newsk)->icsk_pmtu_cookie);
1424
1425                 return newsk;
1426         }
1427
1428         treq = inet6_rsk(req);
1429         opt = np->opt;
1430
1431         if (sk_acceptq_is_full(sk))
1432                 goto out_overflow;
1433
1434         if (!dst) {
1435                 dst = inet6_csk_route_req(sk, req);
1436                 if (!dst)
1437                         goto out;
1438         }
1439
1440         newsk = tcp_create_openreq_child(sk, req, skb);
1441         if (newsk == NULL)
1442                 goto out_nonewsk;
1443
1444         /*
1445          * No need to charge this sock to the relevant IPv6 refcnt debug socks
1446          * count here, tcp_create_openreq_child now does this for us, see the
1447          * comment in that function for the gory details. -acme
1448          */
1449
1450         newsk->sk_gso_type = SKB_GSO_TCPV6;
1451         __ip6_dst_store(newsk, dst, NULL, NULL);
1452
1453         newtcp6sk = (struct tcp6_sock *)newsk;
1454         inet_sk(newsk)->pinet6 = &newtcp6sk->inet6;
1455
1456         newtp = tcp_sk(newsk);
1457         newinet = inet_sk(newsk);
1458         newnp = inet6_sk(newsk);
1459
1460         memcpy(newnp, np, sizeof(struct ipv6_pinfo));
1461
1462         ipv6_addr_copy(&newnp->daddr, &treq->rmt_addr);
1463         ipv6_addr_copy(&newnp->saddr, &treq->loc_addr);
1464         ipv6_addr_copy(&newnp->rcv_saddr, &treq->loc_addr);
1465         newsk->sk_bound_dev_if = treq->iif;
1466
1467         /* Now IPv6 options...
1468
1469            First: no IPv4 options.
1470          */
1471         newinet->opt = NULL;
1472         newnp->ipv6_fl_list = NULL;
1473
1474         /* Clone RX bits */
1475         newnp->rxopt.all = np->rxopt.all;
1476
1477         /* Clone pktoptions received with SYN */
1478         newnp->pktoptions = NULL;
1479         if (treq->pktopts != NULL) {
1480                 newnp->pktoptions = skb_clone(treq->pktopts, GFP_ATOMIC);
1481                 kfree_skb(treq->pktopts);
1482                 treq->pktopts = NULL;
1483                 if (newnp->pktoptions)
1484                         skb_set_owner_r(newnp->pktoptions, newsk);
1485         }
1486         newnp->opt        = NULL;
1487         newnp->mcast_oif  = inet6_iif(skb);
1488         newnp->mcast_hops = ipv6_hdr(skb)->hop_limit;
1489
1490         /* Clone native IPv6 options from listening socket (if any)
1491
1492            Yes, keeping reference count would be much more clever,
1493            but we make one more one thing there: reattach optmem
1494            to newsk.
1495          */
1496         if (opt) {
1497                 newnp->opt = ipv6_dup_options(newsk, opt);
1498                 if (opt != np->opt)
1499                         sock_kfree_s(sk, opt, opt->tot_len);
1500         }
1501
1502         inet_csk(newsk)->icsk_ext_hdr_len = 0;
1503         if (newnp->opt)
1504                 inet_csk(newsk)->icsk_ext_hdr_len = (newnp->opt->opt_nflen +
1505                                                      newnp->opt->opt_flen);
1506
1507         tcp_mtup_init(newsk);
1508         tcp_sync_mss(newsk, dst_mtu(dst));
1509         newtp->advmss = dst_metric_advmss(dst);
1510         tcp_initialize_rcv_mss(newsk);
1511
1512         newinet->inet_daddr = newinet->inet_saddr = LOOPBACK4_IPV6;
1513         newinet->inet_rcv_saddr = LOOPBACK4_IPV6;
1514
1515 #ifdef CONFIG_TCP_MD5SIG
1516         /* Copy over the MD5 key from the original socket */
1517         if ((key = tcp_v6_md5_do_lookup(sk, &newnp->daddr)) != NULL) {
1518                 /* We're using one, so create a matching key
1519                  * on the newsk structure. If we fail to get
1520                  * memory, then we end up not copying the key
1521                  * across. Shucks.
1522                  */
1523                 char *newkey = kmemdup(key->key, key->keylen, GFP_ATOMIC);
1524                 if (newkey != NULL)
1525                         tcp_v6_md5_do_add(newsk, &newnp->daddr,
1526                                           newkey, key->keylen);
1527         }
1528 #endif
1529
1530         if (__inet_inherit_port(sk, newsk) < 0) {
1531                 sock_put(newsk);
1532                 goto out;
1533         }
1534         __inet6_hash(newsk, NULL);
1535
1536         return newsk;
1537
1538 out_overflow:
1539         NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
1540 out_nonewsk:
1541         if (opt && opt != np->opt)
1542                 sock_kfree_s(sk, opt, opt->tot_len);
1543         dst_release(dst);
1544 out:
1545         NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
1546         return NULL;
1547 }
1548
1549 static __sum16 tcp_v6_checksum_init(struct sk_buff *skb)
1550 {
1551         if (skb->ip_summed == CHECKSUM_COMPLETE) {
1552                 if (!tcp_v6_check(skb->len, &ipv6_hdr(skb)->saddr,
1553                                   &ipv6_hdr(skb)->daddr, skb->csum)) {
1554                         skb->ip_summed = CHECKSUM_UNNECESSARY;
1555                         return 0;
1556                 }
1557         }
1558
1559         skb->csum = ~csum_unfold(tcp_v6_check(skb->len,
1560                                               &ipv6_hdr(skb)->saddr,
1561                                               &ipv6_hdr(skb)->daddr, 0));
1562
1563         if (skb->len <= 76) {
1564                 return __skb_checksum_complete(skb);
1565         }
1566         return 0;
1567 }
1568
1569 /* The socket must have it's spinlock held when we get
1570  * here.
1571  *
1572  * We have a potential double-lock case here, so even when
1573  * doing backlog processing we use the BH locking scheme.
1574  * This is because we cannot sleep with the original spinlock
1575  * held.
1576  */
1577 static int tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb)
1578 {
1579         struct ipv6_pinfo *np = inet6_sk(sk);
1580         struct tcp_sock *tp;
1581         struct sk_buff *opt_skb = NULL;
1582
1583         /* Imagine: socket is IPv6. IPv4 packet arrives,
1584            goes to IPv4 receive handler and backlogged.
1585            From backlog it always goes here. Kerboom...
1586            Fortunately, tcp_rcv_established and rcv_established
1587            handle them correctly, but it is not case with
1588            tcp_v6_hnd_req and tcp_v6_send_reset().   --ANK
1589          */
1590
1591         if (skb->protocol == htons(ETH_P_IP))
1592                 return tcp_v4_do_rcv(sk, skb);
1593
1594 #ifdef CONFIG_TCP_MD5SIG
1595         if (tcp_v6_inbound_md5_hash (sk, skb))
1596                 goto discard;
1597 #endif
1598
1599         if (sk_filter(sk, skb))
1600                 goto discard;
1601
1602         /*
1603          *      socket locking is here for SMP purposes as backlog rcv
1604          *      is currently called with bh processing disabled.
1605          */
1606
1607         /* Do Stevens' IPV6_PKTOPTIONS.
1608
1609            Yes, guys, it is the only place in our code, where we
1610            may make it not affecting IPv4.
1611            The rest of code is protocol independent,
1612            and I do not like idea to uglify IPv4.
1613
1614            Actually, all the idea behind IPV6_PKTOPTIONS
1615            looks not very well thought. For now we latch
1616            options, received in the last packet, enqueued
1617            by tcp. Feel free to propose better solution.
1618                                                --ANK (980728)
1619          */
1620         if (np->rxopt.all)
1621                 opt_skb = skb_clone(skb, GFP_ATOMIC);
1622
1623         if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
1624                 if (tcp_rcv_established(sk, skb, tcp_hdr(skb), skb->len))
1625                         goto reset;
1626                 if (opt_skb)
1627                         goto ipv6_pktoptions;
1628                 return 0;
1629         }
1630
1631         if (skb->len < tcp_hdrlen(skb) || tcp_checksum_complete(skb))
1632                 goto csum_err;
1633
1634         if (sk->sk_state == TCP_LISTEN) {
1635                 struct sock *nsk = tcp_v6_hnd_req(sk, skb);
1636                 if (!nsk)
1637                         goto discard;
1638
1639                 /*
1640                  * Queue it on the new socket if the new socket is active,
1641                  * otherwise we just shortcircuit this and continue with
1642                  * the new socket..
1643                  */
1644                 if(nsk != sk) {
1645                         if (tcp_child_process(sk, nsk, skb))
1646                                 goto reset;
1647                         if (opt_skb)
1648                                 __kfree_skb(opt_skb);
1649                         return 0;
1650                 }
1651         }
1652
1653         if (tcp_rcv_state_process(sk, skb, tcp_hdr(skb), skb->len))
1654                 goto reset;
1655         if (opt_skb)
1656                 goto ipv6_pktoptions;
1657         return 0;
1658
1659 reset:
1660         tcp_v6_send_reset(sk, skb);
1661 discard:
1662         if (opt_skb)
1663                 __kfree_skb(opt_skb);
1664         kfree_skb(skb);
1665         return 0;
1666 csum_err:
1667         TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_INERRS);
1668         goto discard;
1669
1670
1671 ipv6_pktoptions:
1672         /* Do you ask, what is it?
1673
1674            1. skb was enqueued by tcp.
1675            2. skb is added to tail of read queue, rather than out of order.
1676            3. socket is not in passive state.
1677            4. Finally, it really contains options, which user wants to receive.
1678          */
1679         tp = tcp_sk(sk);
1680         if (TCP_SKB_CB(opt_skb)->end_seq == tp->rcv_nxt &&
1681             !((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN))) {
1682                 if (np->rxopt.bits.rxinfo || np->rxopt.bits.rxoinfo)
1683                         np->mcast_oif = inet6_iif(opt_skb);
1684                 if (np->rxopt.bits.rxhlim || np->rxopt.bits.rxohlim)
1685                         np->mcast_hops = ipv6_hdr(opt_skb)->hop_limit;
1686                 if (ipv6_opt_accepted(sk, opt_skb)) {
1687                         skb_set_owner_r(opt_skb, sk);
1688                         opt_skb = xchg(&np->pktoptions, opt_skb);
1689                 } else {
1690                         __kfree_skb(opt_skb);
1691                         opt_skb = xchg(&np->pktoptions, NULL);
1692                 }
1693         }
1694
1695         kfree_skb(opt_skb);
1696         return 0;
1697 }
1698
1699 static int tcp_v6_rcv(struct sk_buff *skb)
1700 {
1701         struct tcphdr *th;
1702         struct ipv6hdr *hdr;
1703         struct sock *sk;
1704         int ret;
1705         struct net *net = dev_net(skb->dev);
1706
1707         if (skb->pkt_type != PACKET_HOST)
1708                 goto discard_it;
1709
1710         /*
1711          *      Count it even if it's bad.
1712          */
1713         TCP_INC_STATS_BH(net, TCP_MIB_INSEGS);
1714
1715         if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
1716                 goto discard_it;
1717
1718         th = tcp_hdr(skb);
1719
1720         if (th->doff < sizeof(struct tcphdr)/4)
1721                 goto bad_packet;
1722         if (!pskb_may_pull(skb, th->doff*4))
1723                 goto discard_it;
1724
1725         if (!skb_csum_unnecessary(skb) && tcp_v6_checksum_init(skb))
1726                 goto bad_packet;
1727
1728         th = tcp_hdr(skb);
1729         hdr = ipv6_hdr(skb);
1730         TCP_SKB_CB(skb)->seq = ntohl(th->seq);
1731         TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
1732                                     skb->len - th->doff*4);
1733         TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
1734         TCP_SKB_CB(skb)->when = 0;
1735         TCP_SKB_CB(skb)->flags = ipv6_get_dsfield(hdr);
1736         TCP_SKB_CB(skb)->sacked = 0;
1737
1738         sk = __inet6_lookup_skb(&tcp_hashinfo, skb, th->source, th->dest);
1739         if (!sk)
1740                 goto no_tcp_socket;
1741
1742 process:
1743         if (sk->sk_state == TCP_TIME_WAIT)
1744                 goto do_time_wait;
1745
1746         if (hdr->hop_limit < inet6_sk(sk)->min_hopcount) {
1747                 NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP);
1748                 goto discard_and_relse;
1749         }
1750
1751         if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb))
1752                 goto discard_and_relse;
1753
1754         if (sk_filter(sk, skb))
1755                 goto discard_and_relse;
1756
1757         skb->dev = NULL;
1758
1759         bh_lock_sock_nested(sk);
1760         ret = 0;
1761         if (!sock_owned_by_user(sk)) {
1762 #ifdef CONFIG_NET_DMA
1763                 struct tcp_sock *tp = tcp_sk(sk);
1764                 if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list)
1765                         tp->ucopy.dma_chan = dma_find_channel(DMA_MEMCPY);
1766                 if (tp->ucopy.dma_chan)
1767                         ret = tcp_v6_do_rcv(sk, skb);
1768                 else
1769 #endif
1770                 {
1771                         if (!tcp_prequeue(sk, skb))
1772                                 ret = tcp_v6_do_rcv(sk, skb);
1773                 }
1774         } else if (unlikely(sk_add_backlog(sk, skb))) {
1775                 bh_unlock_sock(sk);
1776                 NET_INC_STATS_BH(net, LINUX_MIB_TCPBACKLOGDROP);
1777                 goto discard_and_relse;
1778         }
1779         bh_unlock_sock(sk);
1780
1781         sock_put(sk);
1782         return ret ? -1 : 0;
1783
1784 no_tcp_socket:
1785         if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb))
1786                 goto discard_it;
1787
1788         if (skb->len < (th->doff<<2) || tcp_checksum_complete(skb)) {
1789 bad_packet:
1790                 TCP_INC_STATS_BH(net, TCP_MIB_INERRS);
1791         } else {
1792                 tcp_v6_send_reset(NULL, skb);
1793         }
1794
1795 discard_it:
1796
1797         /*
1798          *      Discard frame
1799          */
1800
1801         kfree_skb(skb);
1802         return 0;
1803
1804 discard_and_relse:
1805         sock_put(sk);
1806         goto discard_it;
1807
1808 do_time_wait:
1809         if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
1810                 inet_twsk_put(inet_twsk(sk));
1811                 goto discard_it;
1812         }
1813
1814         if (skb->len < (th->doff<<2) || tcp_checksum_complete(skb)) {
1815                 TCP_INC_STATS_BH(net, TCP_MIB_INERRS);
1816                 inet_twsk_put(inet_twsk(sk));
1817                 goto discard_it;
1818         }
1819
1820         switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) {
1821         case TCP_TW_SYN:
1822         {
1823                 struct sock *sk2;
1824
1825                 sk2 = inet6_lookup_listener(dev_net(skb->dev), &tcp_hashinfo,
1826                                             &ipv6_hdr(skb)->daddr,
1827                                             ntohs(th->dest), inet6_iif(skb));
1828                 if (sk2 != NULL) {
1829                         struct inet_timewait_sock *tw = inet_twsk(sk);
1830                         inet_twsk_deschedule(tw, &tcp_death_row);
1831                         inet_twsk_put(tw);
1832                         sk = sk2;
1833                         goto process;
1834                 }
1835                 /* Fall through to ACK */
1836         }
1837         case TCP_TW_ACK:
1838                 tcp_v6_timewait_ack(sk, skb);
1839                 break;
1840         case TCP_TW_RST:
1841                 goto no_tcp_socket;
1842         case TCP_TW_SUCCESS:;
1843         }
1844         goto discard_it;
1845 }
1846
1847 static struct inet_peer *tcp_v6_get_peer(struct sock *sk, bool *release_it)
1848 {
1849         struct rt6_info *rt = (struct rt6_info *) __sk_dst_get(sk);
1850         struct ipv6_pinfo *np = inet6_sk(sk);
1851         struct inet_peer *peer;
1852
1853         if (!rt ||
1854             !ipv6_addr_equal(&np->daddr, &rt->rt6i_dst.addr)) {
1855                 peer = inet_getpeer_v6(&np->daddr, 1);
1856                 *release_it = true;
1857         } else {
1858                 if (!rt->rt6i_peer)
1859                         rt6_bind_peer(rt, 1);
1860                 peer = rt->rt6i_peer;
1861                 *release_it = false;
1862         }
1863
1864         return peer;
1865 }
1866
1867 static void *tcp_v6_tw_get_peer(struct sock *sk)
1868 {
1869         struct inet6_timewait_sock *tw6 = inet6_twsk(sk);
1870         struct inet_timewait_sock *tw = inet_twsk(sk);
1871
1872         if (tw->tw_family == AF_INET)
1873                 return tcp_v4_tw_get_peer(sk);
1874
1875         return inet_getpeer_v6(&tw6->tw_v6_daddr, 1);
1876 }
1877
1878 static struct timewait_sock_ops tcp6_timewait_sock_ops = {
1879         .twsk_obj_size  = sizeof(struct tcp6_timewait_sock),
1880         .twsk_unique    = tcp_twsk_unique,
1881         .twsk_destructor= tcp_twsk_destructor,
1882         .twsk_getpeer   = tcp_v6_tw_get_peer,
1883 };
1884
1885 static const struct inet_connection_sock_af_ops ipv6_specific = {
1886         .queue_xmit        = inet6_csk_xmit,
1887         .send_check        = tcp_v6_send_check,
1888         .rebuild_header    = inet6_sk_rebuild_header,
1889         .conn_request      = tcp_v6_conn_request,
1890         .syn_recv_sock     = tcp_v6_syn_recv_sock,
1891         .get_peer          = tcp_v6_get_peer,
1892         .net_header_len    = sizeof(struct ipv6hdr),
1893         .setsockopt        = ipv6_setsockopt,
1894         .getsockopt        = ipv6_getsockopt,
1895         .addr2sockaddr     = inet6_csk_addr2sockaddr,
1896         .sockaddr_len      = sizeof(struct sockaddr_in6),
1897         .bind_conflict     = inet6_csk_bind_conflict,
1898 #ifdef CONFIG_COMPAT
1899         .compat_setsockopt = compat_ipv6_setsockopt,
1900         .compat_getsockopt = compat_ipv6_getsockopt,
1901 #endif
1902 };
1903
1904 #ifdef CONFIG_TCP_MD5SIG
1905 static const struct tcp_sock_af_ops tcp_sock_ipv6_specific = {
1906         .md5_lookup     =       tcp_v6_md5_lookup,
1907         .calc_md5_hash  =       tcp_v6_md5_hash_skb,
1908         .md5_add        =       tcp_v6_md5_add_func,
1909         .md5_parse      =       tcp_v6_parse_md5_keys,
1910 };
1911 #endif
1912
1913 /*
1914  *      TCP over IPv4 via INET6 API
1915  */
1916
1917 static const struct inet_connection_sock_af_ops ipv6_mapped = {
1918         .queue_xmit        = ip_queue_xmit,
1919         .send_check        = tcp_v4_send_check,
1920         .rebuild_header    = inet_sk_rebuild_header,
1921         .conn_request      = tcp_v6_conn_request,
1922         .syn_recv_sock     = tcp_v6_syn_recv_sock,
1923         .get_peer          = tcp_v4_get_peer,
1924         .net_header_len    = sizeof(struct iphdr),
1925         .setsockopt        = ipv6_setsockopt,
1926         .getsockopt        = ipv6_getsockopt,
1927         .addr2sockaddr     = inet6_csk_addr2sockaddr,
1928         .sockaddr_len      = sizeof(struct sockaddr_in6),
1929         .bind_conflict     = inet6_csk_bind_conflict,
1930 #ifdef CONFIG_COMPAT
1931         .compat_setsockopt = compat_ipv6_setsockopt,
1932         .compat_getsockopt = compat_ipv6_getsockopt,
1933 #endif
1934 };
1935
1936 #ifdef CONFIG_TCP_MD5SIG
1937 static const struct tcp_sock_af_ops tcp_sock_ipv6_mapped_specific = {
1938         .md5_lookup     =       tcp_v4_md5_lookup,
1939         .calc_md5_hash  =       tcp_v4_md5_hash_skb,
1940         .md5_add        =       tcp_v6_md5_add_func,
1941         .md5_parse      =       tcp_v6_parse_md5_keys,
1942 };
1943 #endif
1944
1945 /* NOTE: A lot of things set to zero explicitly by call to
1946  *       sk_alloc() so need not be done here.
1947  */
1948 static int tcp_v6_init_sock(struct sock *sk)
1949 {
1950         struct inet_connection_sock *icsk = inet_csk(sk);
1951         struct tcp_sock *tp = tcp_sk(sk);
1952
1953         skb_queue_head_init(&tp->out_of_order_queue);
1954         tcp_init_xmit_timers(sk);
1955         tcp_prequeue_init(tp);
1956
1957         icsk->icsk_rto = TCP_TIMEOUT_INIT;
1958         tp->mdev = TCP_TIMEOUT_INIT;
1959
1960         /* So many TCP implementations out there (incorrectly) count the
1961          * initial SYN frame in their delayed-ACK and congestion control
1962          * algorithms that we must have the following bandaid to talk
1963          * efficiently to them.  -DaveM
1964          */
1965         tp->snd_cwnd = 2;
1966
1967         /* See draft-stevens-tcpca-spec-01 for discussion of the
1968          * initialization of these values.
1969          */
1970         tp->snd_ssthresh = TCP_INFINITE_SSTHRESH;
1971         tp->snd_cwnd_clamp = ~0;
1972         tp->mss_cache = TCP_MSS_DEFAULT;
1973
1974         tp->reordering = sysctl_tcp_reordering;
1975
1976         sk->sk_state = TCP_CLOSE;
1977
1978         icsk->icsk_af_ops = &ipv6_specific;
1979         icsk->icsk_ca_ops = &tcp_init_congestion_ops;
1980         icsk->icsk_sync_mss = tcp_sync_mss;
1981         sk->sk_write_space = sk_stream_write_space;
1982         sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
1983
1984 #ifdef CONFIG_TCP_MD5SIG
1985         tp->af_specific = &tcp_sock_ipv6_specific;
1986 #endif
1987
1988         /* TCP Cookie Transactions */
1989         if (sysctl_tcp_cookie_size > 0) {
1990                 /* Default, cookies without s_data_payload. */
1991                 tp->cookie_values =
1992                         kzalloc(sizeof(*tp->cookie_values),
1993                                 sk->sk_allocation);
1994                 if (tp->cookie_values != NULL)
1995                         kref_init(&tp->cookie_values->kref);
1996         }
1997         /* Presumed zeroed, in order of appearance:
1998          *      cookie_in_always, cookie_out_never,
1999          *      s_data_constant, s_data_in, s_data_out
2000          */
2001         sk->sk_sndbuf = sysctl_tcp_wmem[1];
2002         sk->sk_rcvbuf = sysctl_tcp_rmem[1];
2003
2004         local_bh_disable();
2005         percpu_counter_inc(&tcp_sockets_allocated);
2006         local_bh_enable();
2007
2008         return 0;
2009 }
2010
2011 static void tcp_v6_destroy_sock(struct sock *sk)
2012 {
2013 #ifdef CONFIG_TCP_MD5SIG
2014         /* Clean up the MD5 key list */
2015         if (tcp_sk(sk)->md5sig_info)
2016                 tcp_v6_clear_md5_list(sk);
2017 #endif
2018         tcp_v4_destroy_sock(sk);
2019         inet6_destroy_sock(sk);
2020 }
2021
2022 #ifdef CONFIG_PROC_FS
2023 /* Proc filesystem TCPv6 sock list dumping. */
2024 static void get_openreq6(struct seq_file *seq,
2025                          struct sock *sk, struct request_sock *req, int i, int uid)
2026 {
2027         int ttd = req->expires - jiffies;
2028         struct in6_addr *src = &inet6_rsk(req)->loc_addr;
2029         struct in6_addr *dest = &inet6_rsk(req)->rmt_addr;
2030
2031         if (ttd < 0)
2032                 ttd = 0;
2033
2034         seq_printf(seq,
2035                    "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
2036                    "%02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %p\n",
2037                    i,
2038                    src->s6_addr32[0], src->s6_addr32[1],
2039                    src->s6_addr32[2], src->s6_addr32[3],
2040                    ntohs(inet_rsk(req)->loc_port),
2041                    dest->s6_addr32[0], dest->s6_addr32[1],
2042                    dest->s6_addr32[2], dest->s6_addr32[3],
2043                    ntohs(inet_rsk(req)->rmt_port),
2044                    TCP_SYN_RECV,
2045                    0,0, /* could print option size, but that is af dependent. */
2046                    1,   /* timers active (only the expire timer) */
2047                    jiffies_to_clock_t(ttd),
2048                    req->retrans,
2049                    uid,
2050                    0,  /* non standard timer */
2051                    0, /* open_requests have no inode */
2052                    0, req);
2053 }
2054
2055 static void get_tcp6_sock(struct seq_file *seq, struct sock *sp, int i)
2056 {
2057         struct in6_addr *dest, *src;
2058         __u16 destp, srcp;
2059         int timer_active;
2060         unsigned long timer_expires;
2061         struct inet_sock *inet = inet_sk(sp);
2062         struct tcp_sock *tp = tcp_sk(sp);
2063         const struct inet_connection_sock *icsk = inet_csk(sp);
2064         struct ipv6_pinfo *np = inet6_sk(sp);
2065
2066         dest  = &np->daddr;
2067         src   = &np->rcv_saddr;
2068         destp = ntohs(inet->inet_dport);
2069         srcp  = ntohs(inet->inet_sport);
2070
2071         if (icsk->icsk_pending == ICSK_TIME_RETRANS) {
2072                 timer_active    = 1;
2073                 timer_expires   = icsk->icsk_timeout;
2074         } else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
2075                 timer_active    = 4;
2076                 timer_expires   = icsk->icsk_timeout;
2077         } else if (timer_pending(&sp->sk_timer)) {
2078                 timer_active    = 2;
2079                 timer_expires   = sp->sk_timer.expires;
2080         } else {
2081                 timer_active    = 0;
2082                 timer_expires = jiffies;
2083         }
2084
2085         seq_printf(seq,
2086                    "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
2087                    "%02X %08X:%08X %02X:%08lX %08X %5d %8d %lu %d %p %lu %lu %u %u %d\n",
2088                    i,
2089                    src->s6_addr32[0], src->s6_addr32[1],
2090                    src->s6_addr32[2], src->s6_addr32[3], srcp,
2091                    dest->s6_addr32[0], dest->s6_addr32[1],
2092                    dest->s6_addr32[2], dest->s6_addr32[3], destp,
2093                    sp->sk_state,
2094                    tp->write_seq-tp->snd_una,
2095                    (sp->sk_state == TCP_LISTEN) ? sp->sk_ack_backlog : (tp->rcv_nxt - tp->copied_seq),
2096                    timer_active,
2097                    jiffies_to_clock_t(timer_expires - jiffies),
2098                    icsk->icsk_retransmits,
2099                    sock_i_uid(sp),
2100                    icsk->icsk_probes_out,
2101                    sock_i_ino(sp),
2102                    atomic_read(&sp->sk_refcnt), sp,
2103                    jiffies_to_clock_t(icsk->icsk_rto),
2104                    jiffies_to_clock_t(icsk->icsk_ack.ato),
2105                    (icsk->icsk_ack.quick << 1 ) | icsk->icsk_ack.pingpong,
2106                    tp->snd_cwnd,
2107                    tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh
2108                    );
2109 }
2110
2111 static void get_timewait6_sock(struct seq_file *seq,
2112                                struct inet_timewait_sock *tw, int i)
2113 {
2114         struct in6_addr *dest, *src;
2115         __u16 destp, srcp;
2116         struct inet6_timewait_sock *tw6 = inet6_twsk((struct sock *)tw);
2117         int ttd = tw->tw_ttd - jiffies;
2118
2119         if (ttd < 0)
2120                 ttd = 0;
2121
2122         dest = &tw6->tw_v6_daddr;
2123         src  = &tw6->tw_v6_rcv_saddr;
2124         destp = ntohs(tw->tw_dport);
2125         srcp  = ntohs(tw->tw_sport);
2126
2127         seq_printf(seq,
2128                    "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
2129                    "%02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %p\n",
2130                    i,
2131                    src->s6_addr32[0], src->s6_addr32[1],
2132                    src->s6_addr32[2], src->s6_addr32[3], srcp,
2133                    dest->s6_addr32[0], dest->s6_addr32[1],
2134                    dest->s6_addr32[2], dest->s6_addr32[3], destp,
2135                    tw->tw_substate, 0, 0,
2136                    3, jiffies_to_clock_t(ttd), 0, 0, 0, 0,
2137                    atomic_read(&tw->tw_refcnt), tw);
2138 }
2139
2140 static int tcp6_seq_show(struct seq_file *seq, void *v)
2141 {
2142         struct tcp_iter_state *st;
2143
2144         if (v == SEQ_START_TOKEN) {
2145                 seq_puts(seq,
2146                          "  sl  "
2147                          "local_address                         "
2148                          "remote_address                        "
2149                          "st tx_queue rx_queue tr tm->when retrnsmt"
2150                          "   uid  timeout inode\n");
2151                 goto out;
2152         }
2153         st = seq->private;
2154
2155         switch (st->state) {
2156         case TCP_SEQ_STATE_LISTENING:
2157         case TCP_SEQ_STATE_ESTABLISHED:
2158                 get_tcp6_sock(seq, v, st->num);
2159                 break;
2160         case TCP_SEQ_STATE_OPENREQ:
2161                 get_openreq6(seq, st->syn_wait_sk, v, st->num, st->uid);
2162                 break;
2163         case TCP_SEQ_STATE_TIME_WAIT:
2164                 get_timewait6_sock(seq, v, st->num);
2165                 break;
2166         }
2167 out:
2168         return 0;
2169 }
2170
2171 static struct tcp_seq_afinfo tcp6_seq_afinfo = {
2172         .name           = "tcp6",
2173         .family         = AF_INET6,
2174         .seq_fops       = {
2175                 .owner          = THIS_MODULE,
2176         },
2177         .seq_ops        = {
2178                 .show           = tcp6_seq_show,
2179         },
2180 };
2181
2182 int __net_init tcp6_proc_init(struct net *net)
2183 {
2184         return tcp_proc_register(net, &tcp6_seq_afinfo);
2185 }
2186
2187 void tcp6_proc_exit(struct net *net)
2188 {
2189         tcp_proc_unregister(net, &tcp6_seq_afinfo);
2190 }
2191 #endif
2192
2193 struct proto tcpv6_prot = {
2194         .name                   = "TCPv6",
2195         .owner                  = THIS_MODULE,
2196         .close                  = tcp_close,
2197         .connect                = tcp_v6_connect,
2198         .disconnect             = tcp_disconnect,
2199         .accept                 = inet_csk_accept,
2200         .ioctl                  = tcp_ioctl,
2201         .init                   = tcp_v6_init_sock,
2202         .destroy                = tcp_v6_destroy_sock,
2203         .shutdown               = tcp_shutdown,
2204         .setsockopt             = tcp_setsockopt,
2205         .getsockopt             = tcp_getsockopt,
2206         .recvmsg                = tcp_recvmsg,
2207         .sendmsg                = tcp_sendmsg,
2208         .sendpage               = tcp_sendpage,
2209         .backlog_rcv            = tcp_v6_do_rcv,
2210         .hash                   = tcp_v6_hash,
2211         .unhash                 = inet_unhash,
2212         .get_port               = inet_csk_get_port,
2213         .enter_memory_pressure  = tcp_enter_memory_pressure,
2214         .sockets_allocated      = &tcp_sockets_allocated,
2215         .memory_allocated       = &tcp_memory_allocated,
2216         .memory_pressure        = &tcp_memory_pressure,
2217         .orphan_count           = &tcp_orphan_count,
2218         .sysctl_mem             = sysctl_tcp_mem,
2219         .sysctl_wmem            = sysctl_tcp_wmem,
2220         .sysctl_rmem            = sysctl_tcp_rmem,
2221         .max_header             = MAX_TCP_HEADER,
2222         .obj_size               = sizeof(struct tcp6_sock),
2223         .slab_flags             = SLAB_DESTROY_BY_RCU,
2224         .twsk_prot              = &tcp6_timewait_sock_ops,
2225         .rsk_prot               = &tcp6_request_sock_ops,
2226         .h.hashinfo             = &tcp_hashinfo,
2227         .no_autobind            = true,
2228 #ifdef CONFIG_COMPAT
2229         .compat_setsockopt      = compat_tcp_setsockopt,
2230         .compat_getsockopt      = compat_tcp_getsockopt,
2231 #endif
2232 };
2233
2234 static const struct inet6_protocol tcpv6_protocol = {
2235         .handler        =       tcp_v6_rcv,
2236         .err_handler    =       tcp_v6_err,
2237         .gso_send_check =       tcp_v6_gso_send_check,
2238         .gso_segment    =       tcp_tso_segment,
2239         .gro_receive    =       tcp6_gro_receive,
2240         .gro_complete   =       tcp6_gro_complete,
2241         .flags          =       INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
2242 };
2243
2244 static struct inet_protosw tcpv6_protosw = {
2245         .type           =       SOCK_STREAM,
2246         .protocol       =       IPPROTO_TCP,
2247         .prot           =       &tcpv6_prot,
2248         .ops            =       &inet6_stream_ops,
2249         .no_check       =       0,
2250         .flags          =       INET_PROTOSW_PERMANENT |
2251                                 INET_PROTOSW_ICSK,
2252 };
2253
2254 static int __net_init tcpv6_net_init(struct net *net)
2255 {
2256         return inet_ctl_sock_create(&net->ipv6.tcp_sk, PF_INET6,
2257                                     SOCK_RAW, IPPROTO_TCP, net);
2258 }
2259
2260 static void __net_exit tcpv6_net_exit(struct net *net)
2261 {
2262         inet_ctl_sock_destroy(net->ipv6.tcp_sk);
2263 }
2264
2265 static void __net_exit tcpv6_net_exit_batch(struct list_head *net_exit_list)
2266 {
2267         inet_twsk_purge(&tcp_hashinfo, &tcp_death_row, AF_INET6);
2268 }
2269
2270 static struct pernet_operations tcpv6_net_ops = {
2271         .init       = tcpv6_net_init,
2272         .exit       = tcpv6_net_exit,
2273         .exit_batch = tcpv6_net_exit_batch,
2274 };
2275
2276 int __init tcpv6_init(void)
2277 {
2278         int ret;
2279
2280         ret = inet6_add_protocol(&tcpv6_protocol, IPPROTO_TCP);
2281         if (ret)
2282                 goto out;
2283
2284         /* register inet6 protocol */
2285         ret = inet6_register_protosw(&tcpv6_protosw);
2286         if (ret)
2287                 goto out_tcpv6_protocol;
2288
2289         ret = register_pernet_subsys(&tcpv6_net_ops);
2290         if (ret)
2291                 goto out_tcpv6_protosw;
2292 out:
2293         return ret;
2294
2295 out_tcpv6_protocol:
2296         inet6_del_protocol(&tcpv6_protocol, IPPROTO_TCP);
2297 out_tcpv6_protosw:
2298         inet6_unregister_protosw(&tcpv6_protosw);
2299         goto out;
2300 }
2301
2302 void tcpv6_exit(void)
2303 {
2304         unregister_pernet_subsys(&tcpv6_net_ops);
2305         inet6_unregister_protosw(&tcpv6_protosw);
2306         inet6_del_protocol(&tcpv6_protocol, IPPROTO_TCP);
2307 }