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TOMOYO Linux Cross Reference
Linux/net/ipv6/tcp_ipv6.c

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  1 /*
  2  *      TCP over IPv6
  3  *      Linux INET6 implementation
  4  *
  5  *      Authors:
  6  *      Pedro Roque             <roque@di.fc.ul.pt>
  7  *
  8  *      Based on:
  9  *      linux/net/ipv4/tcp.c
 10  *      linux/net/ipv4/tcp_input.c
 11  *      linux/net/ipv4/tcp_output.c
 12  *
 13  *      Fixes:
 14  *      Hideaki YOSHIFUJI       :       sin6_scope_id support
 15  *      YOSHIFUJI Hideaki @USAGI and:   Support IPV6_V6ONLY socket option, which
 16  *      Alexey Kuznetsov                allow both IPv4 and IPv6 sockets to bind
 17  *                                      a single port at the same time.
 18  *      YOSHIFUJI Hideaki @USAGI:       convert /proc/net/tcp6 to seq_file.
 19  *
 20  *      This program is free software; you can redistribute it and/or
 21  *      modify it under the terms of the GNU General Public License
 22  *      as published by the Free Software Foundation; either version
 23  *      2 of the License, or (at your option) any later version.
 24  */
 25 
 26 #include <linux/bottom_half.h>
 27 #include <linux/module.h>
 28 #include <linux/errno.h>
 29 #include <linux/types.h>
 30 #include <linux/socket.h>
 31 #include <linux/sockios.h>
 32 #include <linux/net.h>
 33 #include <linux/jiffies.h>
 34 #include <linux/in.h>
 35 #include <linux/in6.h>
 36 #include <linux/netdevice.h>
 37 #include <linux/init.h>
 38 #include <linux/jhash.h>
 39 #include <linux/ipsec.h>
 40 #include <linux/times.h>
 41 #include <linux/slab.h>
 42 #include <linux/uaccess.h>
 43 #include <linux/ipv6.h>
 44 #include <linux/icmpv6.h>
 45 #include <linux/random.h>
 46 
 47 #include <net/tcp.h>
 48 #include <net/ndisc.h>
 49 #include <net/inet6_hashtables.h>
 50 #include <net/inet6_connection_sock.h>
 51 #include <net/ipv6.h>
 52 #include <net/transp_v6.h>
 53 #include <net/addrconf.h>
 54 #include <net/ip6_route.h>
 55 #include <net/ip6_checksum.h>
 56 #include <net/inet_ecn.h>
 57 #include <net/protocol.h>
 58 #include <net/xfrm.h>
 59 #include <net/snmp.h>
 60 #include <net/dsfield.h>
 61 #include <net/timewait_sock.h>
 62 #include <net/inet_common.h>
 63 #include <net/secure_seq.h>
 64 #include <net/tcp_memcontrol.h>
 65 #include <net/busy_poll.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 
 79 static const struct inet_connection_sock_af_ops ipv6_mapped;
 80 static const struct inet_connection_sock_af_ops ipv6_specific;
 81 #ifdef CONFIG_TCP_MD5SIG
 82 static const struct tcp_sock_af_ops tcp_sock_ipv6_specific;
 83 static const struct tcp_sock_af_ops tcp_sock_ipv6_mapped_specific;
 84 #else
 85 static struct tcp_md5sig_key *tcp_v6_md5_do_lookup(struct sock *sk,
 86                                                    const struct in6_addr *addr)
 87 {
 88         return NULL;
 89 }
 90 #endif
 91 
 92 static void inet6_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb)
 93 {
 94         struct dst_entry *dst = skb_dst(skb);
 95 
 96         if (dst && dst_hold_safe(dst)) {
 97                 const struct rt6_info *rt = (const struct rt6_info *)dst;
 98 
 99                 sk->sk_rx_dst = dst;
100                 inet_sk(sk)->rx_dst_ifindex = skb->skb_iif;
101                 inet6_sk(sk)->rx_dst_cookie = rt6_get_cookie(rt);
102         }
103 }
104 
105 static __u32 tcp_v6_init_sequence(const struct sk_buff *skb)
106 {
107         return secure_tcpv6_sequence_number(ipv6_hdr(skb)->daddr.s6_addr32,
108                                             ipv6_hdr(skb)->saddr.s6_addr32,
109                                             tcp_hdr(skb)->dest,
110                                             tcp_hdr(skb)->source);
111 }
112 
113 static int tcp_v6_connect(struct sock *sk, struct sockaddr *uaddr,
114                           int addr_len)
115 {
116         struct sockaddr_in6 *usin = (struct sockaddr_in6 *) uaddr;
117         struct inet_sock *inet = inet_sk(sk);
118         struct inet_connection_sock *icsk = inet_csk(sk);
119         struct ipv6_pinfo *np = inet6_sk(sk);
120         struct tcp_sock *tp = tcp_sk(sk);
121         struct in6_addr *saddr = NULL, *final_p, final;
122         struct ipv6_txoptions *opt;
123         struct flowi6 fl6;
124         struct dst_entry *dst;
125         int addr_type;
126         int err;
127 
128         if (addr_len < SIN6_LEN_RFC2133)
129                 return -EINVAL;
130 
131         if (usin->sin6_family != AF_INET6)
132                 return -EAFNOSUPPORT;
133 
134         memset(&fl6, 0, sizeof(fl6));
135 
136         if (np->sndflow) {
137                 fl6.flowlabel = usin->sin6_flowinfo&IPV6_FLOWINFO_MASK;
138                 IP6_ECN_flow_init(fl6.flowlabel);
139                 if (fl6.flowlabel&IPV6_FLOWLABEL_MASK) {
140                         struct ip6_flowlabel *flowlabel;
141                         flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
142                         if (!flowlabel)
143                                 return -EINVAL;
144                         fl6_sock_release(flowlabel);
145                 }
146         }
147 
148         /*
149          *      connect() to INADDR_ANY means loopback (BSD'ism).
150          */
151 
152         if (ipv6_addr_any(&usin->sin6_addr))
153                 usin->sin6_addr.s6_addr[15] = 0x1;
154 
155         addr_type = ipv6_addr_type(&usin->sin6_addr);
156 
157         if (addr_type & IPV6_ADDR_MULTICAST)
158                 return -ENETUNREACH;
159 
160         if (addr_type&IPV6_ADDR_LINKLOCAL) {
161                 if (addr_len >= sizeof(struct sockaddr_in6) &&
162                     usin->sin6_scope_id) {
163                         /* If interface is set while binding, indices
164                          * must coincide.
165                          */
166                         if (sk->sk_bound_dev_if &&
167                             sk->sk_bound_dev_if != usin->sin6_scope_id)
168                                 return -EINVAL;
169 
170                         sk->sk_bound_dev_if = usin->sin6_scope_id;
171                 }
172 
173                 /* Connect to link-local address requires an interface */
174                 if (!sk->sk_bound_dev_if)
175                         return -EINVAL;
176         }
177 
178         if (tp->rx_opt.ts_recent_stamp &&
179             !ipv6_addr_equal(&sk->sk_v6_daddr, &usin->sin6_addr)) {
180                 tp->rx_opt.ts_recent = 0;
181                 tp->rx_opt.ts_recent_stamp = 0;
182                 tp->write_seq = 0;
183         }
184 
185         sk->sk_v6_daddr = usin->sin6_addr;
186         np->flow_label = fl6.flowlabel;
187 
188         /*
189          *      TCP over IPv4
190          */
191 
192         if (addr_type == IPV6_ADDR_MAPPED) {
193                 u32 exthdrlen = icsk->icsk_ext_hdr_len;
194                 struct sockaddr_in sin;
195 
196                 SOCK_DEBUG(sk, "connect: ipv4 mapped\n");
197 
198                 if (__ipv6_only_sock(sk))
199                         return -ENETUNREACH;
200 
201                 sin.sin_family = AF_INET;
202                 sin.sin_port = usin->sin6_port;
203                 sin.sin_addr.s_addr = usin->sin6_addr.s6_addr32[3];
204 
205                 icsk->icsk_af_ops = &ipv6_mapped;
206                 sk->sk_backlog_rcv = tcp_v4_do_rcv;
207 #ifdef CONFIG_TCP_MD5SIG
208                 tp->af_specific = &tcp_sock_ipv6_mapped_specific;
209 #endif
210 
211                 err = tcp_v4_connect(sk, (struct sockaddr *)&sin, sizeof(sin));
212 
213                 if (err) {
214                         icsk->icsk_ext_hdr_len = exthdrlen;
215                         icsk->icsk_af_ops = &ipv6_specific;
216                         sk->sk_backlog_rcv = tcp_v6_do_rcv;
217 #ifdef CONFIG_TCP_MD5SIG
218                         tp->af_specific = &tcp_sock_ipv6_specific;
219 #endif
220                         goto failure;
221                 }
222                 np->saddr = sk->sk_v6_rcv_saddr;
223 
224                 return err;
225         }
226 
227         if (!ipv6_addr_any(&sk->sk_v6_rcv_saddr))
228                 saddr = &sk->sk_v6_rcv_saddr;
229 
230         fl6.flowi6_proto = IPPROTO_TCP;
231         fl6.daddr = sk->sk_v6_daddr;
232         fl6.saddr = saddr ? *saddr : np->saddr;
233         fl6.flowi6_oif = sk->sk_bound_dev_if;
234         fl6.flowi6_mark = sk->sk_mark;
235         fl6.fl6_dport = usin->sin6_port;
236         fl6.fl6_sport = inet->inet_sport;
237 
238         opt = rcu_dereference_protected(np->opt, sock_owned_by_user(sk));
239         final_p = fl6_update_dst(&fl6, opt, &final);
240 
241         security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));
242 
243         dst = ip6_dst_lookup_flow(sk, &fl6, final_p);
244         if (IS_ERR(dst)) {
245                 err = PTR_ERR(dst);
246                 goto failure;
247         }
248 
249         if (!saddr) {
250                 saddr = &fl6.saddr;
251                 sk->sk_v6_rcv_saddr = *saddr;
252         }
253 
254         /* set the source address */
255         np->saddr = *saddr;
256         inet->inet_rcv_saddr = LOOPBACK4_IPV6;
257 
258         sk->sk_gso_type = SKB_GSO_TCPV6;
259         __ip6_dst_store(sk, dst, NULL, NULL);
260 
261         if (tcp_death_row.sysctl_tw_recycle &&
262             !tp->rx_opt.ts_recent_stamp &&
263             ipv6_addr_equal(&fl6.daddr, &sk->sk_v6_daddr))
264                 tcp_fetch_timewait_stamp(sk, dst);
265 
266         icsk->icsk_ext_hdr_len = 0;
267         if (opt)
268                 icsk->icsk_ext_hdr_len = opt->opt_flen +
269                                          opt->opt_nflen;
270 
271         tp->rx_opt.mss_clamp = IPV6_MIN_MTU - sizeof(struct tcphdr) - sizeof(struct ipv6hdr);
272 
273         inet->inet_dport = usin->sin6_port;
274 
275         tcp_set_state(sk, TCP_SYN_SENT);
276         err = inet6_hash_connect(&tcp_death_row, sk);
277         if (err)
278                 goto late_failure;
279 
280         sk_set_txhash(sk);
281 
282         if (!tp->write_seq && likely(!tp->repair))
283                 tp->write_seq = secure_tcpv6_sequence_number(np->saddr.s6_addr32,
284                                                              sk->sk_v6_daddr.s6_addr32,
285                                                              inet->inet_sport,
286                                                              inet->inet_dport);
287 
288         err = tcp_connect(sk);
289         if (err)
290                 goto late_failure;
291 
292         return 0;
293 
294 late_failure:
295         tcp_set_state(sk, TCP_CLOSE);
296         __sk_dst_reset(sk);
297 failure:
298         inet->inet_dport = 0;
299         sk->sk_route_caps = 0;
300         return err;
301 }
302 
303 static void tcp_v6_mtu_reduced(struct sock *sk)
304 {
305         struct dst_entry *dst;
306 
307         if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE))
308                 return;
309 
310         dst = inet6_csk_update_pmtu(sk, tcp_sk(sk)->mtu_info);
311         if (!dst)
312                 return;
313 
314         if (inet_csk(sk)->icsk_pmtu_cookie > dst_mtu(dst)) {
315                 tcp_sync_mss(sk, dst_mtu(dst));
316                 tcp_simple_retransmit(sk);
317         }
318 }
319 
320 static void tcp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
321                 u8 type, u8 code, int offset, __be32 info)
322 {
323         const struct ipv6hdr *hdr = (const struct ipv6hdr *)skb->data;
324         const struct tcphdr *th = (struct tcphdr *)(skb->data+offset);
325         struct net *net = dev_net(skb->dev);
326         struct request_sock *fastopen;
327         struct ipv6_pinfo *np;
328         struct tcp_sock *tp;
329         __u32 seq, snd_una;
330         struct sock *sk;
331         int err;
332 
333         sk = __inet6_lookup_established(net, &tcp_hashinfo,
334                                         &hdr->daddr, th->dest,
335                                         &hdr->saddr, ntohs(th->source),
336                                         skb->dev->ifindex);
337 
338         if (!sk) {
339                 ICMP6_INC_STATS_BH(net, __in6_dev_get(skb->dev),
340                                    ICMP6_MIB_INERRORS);
341                 return;
342         }
343 
344         if (sk->sk_state == TCP_TIME_WAIT) {
345                 inet_twsk_put(inet_twsk(sk));
346                 return;
347         }
348         seq = ntohl(th->seq);
349         if (sk->sk_state == TCP_NEW_SYN_RECV)
350                 return tcp_req_err(sk, seq);
351 
352         bh_lock_sock(sk);
353         if (sock_owned_by_user(sk) && type != ICMPV6_PKT_TOOBIG)
354                 NET_INC_STATS_BH(net, LINUX_MIB_LOCKDROPPEDICMPS);
355 
356         if (sk->sk_state == TCP_CLOSE)
357                 goto out;
358 
359         if (ipv6_hdr(skb)->hop_limit < inet6_sk(sk)->min_hopcount) {
360                 NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP);
361                 goto out;
362         }
363 
364         tp = tcp_sk(sk);
365         /* XXX (TFO) - tp->snd_una should be ISN (tcp_create_openreq_child() */
366         fastopen = tp->fastopen_rsk;
367         snd_una = fastopen ? tcp_rsk(fastopen)->snt_isn : tp->snd_una;
368         if (sk->sk_state != TCP_LISTEN &&
369             !between(seq, snd_una, tp->snd_nxt)) {
370                 NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
371                 goto out;
372         }
373 
374         np = inet6_sk(sk);
375 
376         if (type == NDISC_REDIRECT) {
377                 struct dst_entry *dst = __sk_dst_check(sk, np->dst_cookie);
378 
379                 if (dst)
380                         dst->ops->redirect(dst, sk, skb);
381                 goto out;
382         }
383 
384         if (type == ICMPV6_PKT_TOOBIG) {
385                 /* We are not interested in TCP_LISTEN and open_requests
386                  * (SYN-ACKs send out by Linux are always <576bytes so
387                  * they should go through unfragmented).
388                  */
389                 if (sk->sk_state == TCP_LISTEN)
390                         goto out;
391 
392                 if (!ip6_sk_accept_pmtu(sk))
393                         goto out;
394 
395                 tp->mtu_info = ntohl(info);
396                 if (!sock_owned_by_user(sk))
397                         tcp_v6_mtu_reduced(sk);
398                 else if (!test_and_set_bit(TCP_MTU_REDUCED_DEFERRED,
399                                            &tp->tsq_flags))
400                         sock_hold(sk);
401                 goto out;
402         }
403 
404         icmpv6_err_convert(type, code, &err);
405 
406         /* Might be for an request_sock */
407         switch (sk->sk_state) {
408         case TCP_SYN_SENT:
409         case TCP_SYN_RECV:
410                 /* Only in fast or simultaneous open. If a fast open socket is
411                  * is already accepted it is treated as a connected one below.
412                  */
413                 if (fastopen && !fastopen->sk)
414                         break;
415 
416                 if (!sock_owned_by_user(sk)) {
417                         sk->sk_err = err;
418                         sk->sk_error_report(sk);                /* Wake people up to see the error (see connect in sock.c) */
419 
420                         tcp_done(sk);
421                 } else
422                         sk->sk_err_soft = err;
423                 goto out;
424         }
425 
426         if (!sock_owned_by_user(sk) && np->recverr) {
427                 sk->sk_err = err;
428                 sk->sk_error_report(sk);
429         } else
430                 sk->sk_err_soft = err;
431 
432 out:
433         bh_unlock_sock(sk);
434         sock_put(sk);
435 }
436 
437 
438 static int tcp_v6_send_synack(struct sock *sk, struct dst_entry *dst,
439                               struct flowi *fl,
440                               struct request_sock *req,
441                               u16 queue_mapping,
442                               struct tcp_fastopen_cookie *foc)
443 {
444         struct inet_request_sock *ireq = inet_rsk(req);
445         struct ipv6_pinfo *np = inet6_sk(sk);
446         struct flowi6 *fl6 = &fl->u.ip6;
447         struct sk_buff *skb;
448         int err = -ENOMEM;
449 
450         /* First, grab a route. */
451         if (!dst && (dst = inet6_csk_route_req(sk, fl6, req)) == NULL)
452                 goto done;
453 
454         skb = tcp_make_synack(sk, dst, req, foc);
455 
456         if (skb) {
457                 __tcp_v6_send_check(skb, &ireq->ir_v6_loc_addr,
458                                     &ireq->ir_v6_rmt_addr);
459 
460                 fl6->daddr = ireq->ir_v6_rmt_addr;
461                 if (np->repflow && ireq->pktopts)
462                         fl6->flowlabel = ip6_flowlabel(ipv6_hdr(ireq->pktopts));
463 
464                 skb_set_queue_mapping(skb, queue_mapping);
465                 rcu_read_lock();
466                 err = ip6_xmit(sk, skb, fl6, rcu_dereference(np->opt),
467                                np->tclass);
468                 rcu_read_unlock();
469                 err = net_xmit_eval(err);
470         }
471 
472 done:
473         return err;
474 }
475 
476 
477 static void tcp_v6_reqsk_destructor(struct request_sock *req)
478 {
479         kfree_skb(inet_rsk(req)->pktopts);
480 }
481 
482 #ifdef CONFIG_TCP_MD5SIG
483 static struct tcp_md5sig_key *tcp_v6_md5_do_lookup(struct sock *sk,
484                                                    const struct in6_addr *addr)
485 {
486         return tcp_md5_do_lookup(sk, (union tcp_md5_addr *)addr, AF_INET6);
487 }
488 
489 static struct tcp_md5sig_key *tcp_v6_md5_lookup(struct sock *sk,
490                                                 const struct sock *addr_sk)
491 {
492         return tcp_v6_md5_do_lookup(sk, &addr_sk->sk_v6_daddr);
493 }
494 
495 static int tcp_v6_parse_md5_keys(struct sock *sk, char __user *optval,
496                                  int optlen)
497 {
498         struct tcp_md5sig cmd;
499         struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)&cmd.tcpm_addr;
500 
501         if (optlen < sizeof(cmd))
502                 return -EINVAL;
503 
504         if (copy_from_user(&cmd, optval, sizeof(cmd)))
505                 return -EFAULT;
506 
507         if (sin6->sin6_family != AF_INET6)
508                 return -EINVAL;
509 
510         if (!cmd.tcpm_keylen) {
511                 if (ipv6_addr_v4mapped(&sin6->sin6_addr))
512                         return tcp_md5_do_del(sk, (union tcp_md5_addr *)&sin6->sin6_addr.s6_addr32[3],
513                                               AF_INET);
514                 return tcp_md5_do_del(sk, (union tcp_md5_addr *)&sin6->sin6_addr,
515                                       AF_INET6);
516         }
517 
518         if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN)
519                 return -EINVAL;
520 
521         if (ipv6_addr_v4mapped(&sin6->sin6_addr))
522                 return tcp_md5_do_add(sk, (union tcp_md5_addr *)&sin6->sin6_addr.s6_addr32[3],
523                                       AF_INET, cmd.tcpm_key, cmd.tcpm_keylen, GFP_KERNEL);
524 
525         return tcp_md5_do_add(sk, (union tcp_md5_addr *)&sin6->sin6_addr,
526                               AF_INET6, cmd.tcpm_key, cmd.tcpm_keylen, GFP_KERNEL);
527 }
528 
529 static int tcp_v6_md5_hash_pseudoheader(struct tcp_md5sig_pool *hp,
530                                         const struct in6_addr *daddr,
531                                         const struct in6_addr *saddr, int nbytes)
532 {
533         struct tcp6_pseudohdr *bp;
534         struct scatterlist sg;
535 
536         bp = &hp->md5_blk.ip6;
537         /* 1. TCP pseudo-header (RFC2460) */
538         bp->saddr = *saddr;
539         bp->daddr = *daddr;
540         bp->protocol = cpu_to_be32(IPPROTO_TCP);
541         bp->len = cpu_to_be32(nbytes);
542 
543         sg_init_one(&sg, bp, sizeof(*bp));
544         return crypto_hash_update(&hp->md5_desc, &sg, sizeof(*bp));
545 }
546 
547 static int tcp_v6_md5_hash_hdr(char *md5_hash, struct tcp_md5sig_key *key,
548                                const struct in6_addr *daddr, struct in6_addr *saddr,
549                                const struct tcphdr *th)
550 {
551         struct tcp_md5sig_pool *hp;
552         struct hash_desc *desc;
553 
554         hp = tcp_get_md5sig_pool();
555         if (!hp)
556                 goto clear_hash_noput;
557         desc = &hp->md5_desc;
558 
559         if (crypto_hash_init(desc))
560                 goto clear_hash;
561         if (tcp_v6_md5_hash_pseudoheader(hp, daddr, saddr, th->doff << 2))
562                 goto clear_hash;
563         if (tcp_md5_hash_header(hp, th))
564                 goto clear_hash;
565         if (tcp_md5_hash_key(hp, key))
566                 goto clear_hash;
567         if (crypto_hash_final(desc, md5_hash))
568                 goto clear_hash;
569 
570         tcp_put_md5sig_pool();
571         return 0;
572 
573 clear_hash:
574         tcp_put_md5sig_pool();
575 clear_hash_noput:
576         memset(md5_hash, 0, 16);
577         return 1;
578 }
579 
580 static int tcp_v6_md5_hash_skb(char *md5_hash,
581                                const struct tcp_md5sig_key *key,
582                                const struct sock *sk,
583                                const struct sk_buff *skb)
584 {
585         const struct in6_addr *saddr, *daddr;
586         struct tcp_md5sig_pool *hp;
587         struct hash_desc *desc;
588         const struct tcphdr *th = tcp_hdr(skb);
589 
590         if (sk) { /* valid for establish/request sockets */
591                 saddr = &sk->sk_v6_rcv_saddr;
592                 daddr = &sk->sk_v6_daddr;
593         } else {
594                 const struct ipv6hdr *ip6h = ipv6_hdr(skb);
595                 saddr = &ip6h->saddr;
596                 daddr = &ip6h->daddr;
597         }
598 
599         hp = tcp_get_md5sig_pool();
600         if (!hp)
601                 goto clear_hash_noput;
602         desc = &hp->md5_desc;
603 
604         if (crypto_hash_init(desc))
605                 goto clear_hash;
606 
607         if (tcp_v6_md5_hash_pseudoheader(hp, daddr, saddr, skb->len))
608                 goto clear_hash;
609         if (tcp_md5_hash_header(hp, th))
610                 goto clear_hash;
611         if (tcp_md5_hash_skb_data(hp, skb, th->doff << 2))
612                 goto clear_hash;
613         if (tcp_md5_hash_key(hp, key))
614                 goto clear_hash;
615         if (crypto_hash_final(desc, md5_hash))
616                 goto clear_hash;
617 
618         tcp_put_md5sig_pool();
619         return 0;
620 
621 clear_hash:
622         tcp_put_md5sig_pool();
623 clear_hash_noput:
624         memset(md5_hash, 0, 16);
625         return 1;
626 }
627 
628 static bool tcp_v6_inbound_md5_hash(struct sock *sk, const struct sk_buff *skb)
629 {
630         const __u8 *hash_location = NULL;
631         struct tcp_md5sig_key *hash_expected;
632         const struct ipv6hdr *ip6h = ipv6_hdr(skb);
633         const struct tcphdr *th = tcp_hdr(skb);
634         int genhash;
635         u8 newhash[16];
636 
637         hash_expected = tcp_v6_md5_do_lookup(sk, &ip6h->saddr);
638         hash_location = tcp_parse_md5sig_option(th);
639 
640         /* We've parsed the options - do we have a hash? */
641         if (!hash_expected && !hash_location)
642                 return false;
643 
644         if (hash_expected && !hash_location) {
645                 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5NOTFOUND);
646                 return true;
647         }
648 
649         if (!hash_expected && hash_location) {
650                 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5UNEXPECTED);
651                 return true;
652         }
653 
654         /* check the signature */
655         genhash = tcp_v6_md5_hash_skb(newhash,
656                                       hash_expected,
657                                       NULL, skb);
658 
659         if (genhash || memcmp(hash_location, newhash, 16) != 0) {
660                 net_info_ratelimited("MD5 Hash %s for [%pI6c]:%u->[%pI6c]:%u\n",
661                                      genhash ? "failed" : "mismatch",
662                                      &ip6h->saddr, ntohs(th->source),
663                                      &ip6h->daddr, ntohs(th->dest));
664                 return true;
665         }
666         return false;
667 }
668 #endif
669 
670 static void tcp_v6_init_req(struct request_sock *req, struct sock *sk,
671                             struct sk_buff *skb)
672 {
673         struct inet_request_sock *ireq = inet_rsk(req);
674         struct ipv6_pinfo *np = inet6_sk(sk);
675 
676         ireq->ir_v6_rmt_addr = ipv6_hdr(skb)->saddr;
677         ireq->ir_v6_loc_addr = ipv6_hdr(skb)->daddr;
678 
679         /* So that link locals have meaning */
680         if (!sk->sk_bound_dev_if &&
681             ipv6_addr_type(&ireq->ir_v6_rmt_addr) & IPV6_ADDR_LINKLOCAL)
682                 ireq->ir_iif = tcp_v6_iif(skb);
683 
684         if (!TCP_SKB_CB(skb)->tcp_tw_isn &&
685             (ipv6_opt_accepted(sk, skb, &TCP_SKB_CB(skb)->header.h6) ||
686              np->rxopt.bits.rxinfo ||
687              np->rxopt.bits.rxoinfo || np->rxopt.bits.rxhlim ||
688              np->rxopt.bits.rxohlim || np->repflow)) {
689                 atomic_inc(&skb->users);
690                 ireq->pktopts = skb;
691         }
692 }
693 
694 static struct dst_entry *tcp_v6_route_req(struct sock *sk, struct flowi *fl,
695                                           const struct request_sock *req,
696                                           bool *strict)
697 {
698         if (strict)
699                 *strict = true;
700         return inet6_csk_route_req(sk, &fl->u.ip6, req);
701 }
702 
703 struct request_sock_ops tcp6_request_sock_ops __read_mostly = {
704         .family         =       AF_INET6,
705         .obj_size       =       sizeof(struct tcp6_request_sock),
706         .rtx_syn_ack    =       tcp_rtx_synack,
707         .send_ack       =       tcp_v6_reqsk_send_ack,
708         .destructor     =       tcp_v6_reqsk_destructor,
709         .send_reset     =       tcp_v6_send_reset,
710         .syn_ack_timeout =      tcp_syn_ack_timeout,
711 };
712 
713 static const struct tcp_request_sock_ops tcp_request_sock_ipv6_ops = {
714         .mss_clamp      =       IPV6_MIN_MTU - sizeof(struct tcphdr) -
715                                 sizeof(struct ipv6hdr),
716 #ifdef CONFIG_TCP_MD5SIG
717         .req_md5_lookup =       tcp_v6_md5_lookup,
718         .calc_md5_hash  =       tcp_v6_md5_hash_skb,
719 #endif
720         .init_req       =       tcp_v6_init_req,
721 #ifdef CONFIG_SYN_COOKIES
722         .cookie_init_seq =      cookie_v6_init_sequence,
723 #endif
724         .route_req      =       tcp_v6_route_req,
725         .init_seq       =       tcp_v6_init_sequence,
726         .send_synack    =       tcp_v6_send_synack,
727         .queue_hash_add =       inet6_csk_reqsk_queue_hash_add,
728 };
729 
730 static void tcp_v6_send_response(struct sock *sk, struct sk_buff *skb, u32 seq,
731                                  u32 ack, u32 win, u32 tsval, u32 tsecr,
732                                  int oif, struct tcp_md5sig_key *key, int rst,
733                                  u8 tclass, u32 label)
734 {
735         const struct tcphdr *th = tcp_hdr(skb);
736         struct tcphdr *t1;
737         struct sk_buff *buff;
738         struct flowi6 fl6;
739         struct net *net = sk ? sock_net(sk) : dev_net(skb_dst(skb)->dev);
740         struct sock *ctl_sk = net->ipv6.tcp_sk;
741         unsigned int tot_len = sizeof(struct tcphdr);
742         struct dst_entry *dst;
743         __be32 *topt;
744 
745         if (tsecr)
746                 tot_len += TCPOLEN_TSTAMP_ALIGNED;
747 #ifdef CONFIG_TCP_MD5SIG
748         if (key)
749                 tot_len += TCPOLEN_MD5SIG_ALIGNED;
750 #endif
751 
752         buff = alloc_skb(MAX_HEADER + sizeof(struct ipv6hdr) + tot_len,
753                          GFP_ATOMIC);
754         if (!buff)
755                 return;
756 
757         skb_reserve(buff, MAX_HEADER + sizeof(struct ipv6hdr) + tot_len);
758 
759         t1 = (struct tcphdr *) skb_push(buff, tot_len);
760         skb_reset_transport_header(buff);
761 
762         /* Swap the send and the receive. */
763         memset(t1, 0, sizeof(*t1));
764         t1->dest = th->source;
765         t1->source = th->dest;
766         t1->doff = tot_len / 4;
767         t1->seq = htonl(seq);
768         t1->ack_seq = htonl(ack);
769         t1->ack = !rst || !th->ack;
770         t1->rst = rst;
771         t1->window = htons(win);
772 
773         topt = (__be32 *)(t1 + 1);
774 
775         if (tsecr) {
776                 *topt++ = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
777                                 (TCPOPT_TIMESTAMP << 8) | TCPOLEN_TIMESTAMP);
778                 *topt++ = htonl(tsval);
779                 *topt++ = htonl(tsecr);
780         }
781 
782 #ifdef CONFIG_TCP_MD5SIG
783         if (key) {
784                 *topt++ = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
785                                 (TCPOPT_MD5SIG << 8) | TCPOLEN_MD5SIG);
786                 tcp_v6_md5_hash_hdr((__u8 *)topt, key,
787                                     &ipv6_hdr(skb)->saddr,
788                                     &ipv6_hdr(skb)->daddr, t1);
789         }
790 #endif
791 
792         memset(&fl6, 0, sizeof(fl6));
793         fl6.daddr = ipv6_hdr(skb)->saddr;
794         fl6.saddr = ipv6_hdr(skb)->daddr;
795         fl6.flowlabel = label;
796 
797         buff->ip_summed = CHECKSUM_PARTIAL;
798         buff->csum = 0;
799 
800         __tcp_v6_send_check(buff, &fl6.saddr, &fl6.daddr);
801 
802         fl6.flowi6_proto = IPPROTO_TCP;
803         if (rt6_need_strict(&fl6.daddr) && !oif)
804                 fl6.flowi6_oif = tcp_v6_iif(skb);
805         else
806                 fl6.flowi6_oif = oif;
807         fl6.flowi6_mark = IP6_REPLY_MARK(net, skb->mark);
808         fl6.fl6_dport = t1->dest;
809         fl6.fl6_sport = t1->source;
810         security_skb_classify_flow(skb, flowi6_to_flowi(&fl6));
811 
812         /* Pass a socket to ip6_dst_lookup either it is for RST
813          * Underlying function will use this to retrieve the network
814          * namespace
815          */
816         dst = ip6_dst_lookup_flow(ctl_sk, &fl6, NULL);
817         if (!IS_ERR(dst)) {
818                 skb_dst_set(buff, dst);
819                 ip6_xmit(ctl_sk, buff, &fl6, NULL, tclass);
820                 TCP_INC_STATS_BH(net, TCP_MIB_OUTSEGS);
821                 if (rst)
822                         TCP_INC_STATS_BH(net, TCP_MIB_OUTRSTS);
823                 return;
824         }
825 
826         kfree_skb(buff);
827 }
828 
829 static void tcp_v6_send_reset(struct sock *sk, struct sk_buff *skb)
830 {
831         const struct tcphdr *th = tcp_hdr(skb);
832         u32 seq = 0, ack_seq = 0;
833         struct tcp_md5sig_key *key = NULL;
834 #ifdef CONFIG_TCP_MD5SIG
835         const __u8 *hash_location = NULL;
836         struct ipv6hdr *ipv6h = ipv6_hdr(skb);
837         unsigned char newhash[16];
838         int genhash;
839         struct sock *sk1 = NULL;
840 #endif
841         int oif;
842 
843         if (th->rst)
844                 return;
845 
846         /* If sk not NULL, it means we did a successful lookup and incoming
847          * route had to be correct. prequeue might have dropped our dst.
848          */
849         if (!sk && !ipv6_unicast_destination(skb))
850                 return;
851 
852 #ifdef CONFIG_TCP_MD5SIG
853         hash_location = tcp_parse_md5sig_option(th);
854         if (!sk && hash_location) {
855                 /*
856                  * active side is lost. Try to find listening socket through
857                  * source port, and then find md5 key through listening socket.
858                  * we are not loose security here:
859                  * Incoming packet is checked with md5 hash with finding key,
860                  * no RST generated if md5 hash doesn't match.
861                  */
862                 sk1 = inet6_lookup_listener(dev_net(skb_dst(skb)->dev),
863                                            &tcp_hashinfo, &ipv6h->saddr,
864                                            th->source, &ipv6h->daddr,
865                                            ntohs(th->source), tcp_v6_iif(skb));
866                 if (!sk1)
867                         return;
868 
869                 rcu_read_lock();
870                 key = tcp_v6_md5_do_lookup(sk1, &ipv6h->saddr);
871                 if (!key)
872                         goto release_sk1;
873 
874                 genhash = tcp_v6_md5_hash_skb(newhash, key, NULL, skb);
875                 if (genhash || memcmp(hash_location, newhash, 16) != 0)
876                         goto release_sk1;
877         } else {
878                 key = sk ? tcp_v6_md5_do_lookup(sk, &ipv6h->saddr) : NULL;
879         }
880 #endif
881 
882         if (th->ack)
883                 seq = ntohl(th->ack_seq);
884         else
885                 ack_seq = ntohl(th->seq) + th->syn + th->fin + skb->len -
886                           (th->doff << 2);
887 
888         oif = sk ? sk->sk_bound_dev_if : 0;
889         tcp_v6_send_response(sk, skb, seq, ack_seq, 0, 0, 0, oif, key, 1, 0, 0);
890 
891 #ifdef CONFIG_TCP_MD5SIG
892 release_sk1:
893         if (sk1) {
894                 rcu_read_unlock();
895                 sock_put(sk1);
896         }
897 #endif
898 }
899 
900 static void tcp_v6_send_ack(struct sock *sk, struct sk_buff *skb, u32 seq,
901                             u32 ack, u32 win, u32 tsval, u32 tsecr, int oif,
902                             struct tcp_md5sig_key *key, u8 tclass,
903                             u32 label)
904 {
905         tcp_v6_send_response(sk, skb, seq, ack, win, tsval, tsecr, oif, key, 0,
906                              tclass, label);
907 }
908 
909 static void tcp_v6_timewait_ack(struct sock *sk, struct sk_buff *skb)
910 {
911         struct inet_timewait_sock *tw = inet_twsk(sk);
912         struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
913 
914         tcp_v6_send_ack(sk, skb, tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
915                         tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
916                         tcp_time_stamp + tcptw->tw_ts_offset,
917                         tcptw->tw_ts_recent, tw->tw_bound_dev_if, tcp_twsk_md5_key(tcptw),
918                         tw->tw_tclass, cpu_to_be32(tw->tw_flowlabel));
919 
920         inet_twsk_put(tw);
921 }
922 
923 static void tcp_v6_reqsk_send_ack(struct sock *sk, struct sk_buff *skb,
924                                   struct request_sock *req)
925 {
926         /* sk->sk_state == TCP_LISTEN -> for regular TCP_SYN_RECV
927          * sk->sk_state == TCP_SYN_RECV -> for Fast Open.
928          */
929         tcp_v6_send_ack(sk, skb, (sk->sk_state == TCP_LISTEN) ?
930                         tcp_rsk(req)->snt_isn + 1 : tcp_sk(sk)->snd_nxt,
931                         tcp_rsk(req)->rcv_nxt, req->rcv_wnd,
932                         tcp_time_stamp, req->ts_recent, sk->sk_bound_dev_if,
933                         tcp_v6_md5_do_lookup(sk, &ipv6_hdr(skb)->daddr),
934                         0, 0);
935 }
936 
937 
938 static struct sock *tcp_v6_hnd_req(struct sock *sk, struct sk_buff *skb)
939 {
940         const struct tcphdr *th = tcp_hdr(skb);
941         struct request_sock *req;
942         struct sock *nsk;
943 
944         /* Find possible connection requests. */
945         req = inet6_csk_search_req(sk, th->source,
946                                    &ipv6_hdr(skb)->saddr,
947                                    &ipv6_hdr(skb)->daddr, tcp_v6_iif(skb));
948         if (req) {
949                 nsk = tcp_check_req(sk, skb, req, false);
950                 if (!nsk || nsk == sk)
951                         reqsk_put(req);
952                 return nsk;
953         }
954         nsk = __inet6_lookup_established(sock_net(sk), &tcp_hashinfo,
955                                          &ipv6_hdr(skb)->saddr, th->source,
956                                          &ipv6_hdr(skb)->daddr, ntohs(th->dest),
957                                          tcp_v6_iif(skb));
958 
959         if (nsk) {
960                 if (nsk->sk_state != TCP_TIME_WAIT) {
961                         bh_lock_sock(nsk);
962                         return nsk;
963                 }
964                 inet_twsk_put(inet_twsk(nsk));
965                 return NULL;
966         }
967 
968 #ifdef CONFIG_SYN_COOKIES
969         if (!th->syn)
970                 sk = cookie_v6_check(sk, skb);
971 #endif
972         return sk;
973 }
974 
975 static int tcp_v6_conn_request(struct sock *sk, struct sk_buff *skb)
976 {
977         if (skb->protocol == htons(ETH_P_IP))
978                 return tcp_v4_conn_request(sk, skb);
979 
980         if (!ipv6_unicast_destination(skb))
981                 goto drop;
982 
983         return tcp_conn_request(&tcp6_request_sock_ops,
984                                 &tcp_request_sock_ipv6_ops, sk, skb);
985 
986 drop:
987         NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
988         return 0; /* don't send reset */
989 }
990 
991 static struct sock *tcp_v6_syn_recv_sock(struct sock *sk, struct sk_buff *skb,
992                                          struct request_sock *req,
993                                          struct dst_entry *dst)
994 {
995         struct inet_request_sock *ireq;
996         struct ipv6_pinfo *newnp, *np = inet6_sk(sk);
997         struct tcp6_sock *newtcp6sk;
998         struct ipv6_txoptions *opt;
999         struct inet_sock *newinet;
1000         struct tcp_sock *newtp;
1001         struct sock *newsk;
1002 #ifdef CONFIG_TCP_MD5SIG
1003         struct tcp_md5sig_key *key;
1004 #endif
1005         struct flowi6 fl6;
1006 
1007         if (skb->protocol == htons(ETH_P_IP)) {
1008                 /*
1009                  *      v6 mapped
1010                  */
1011 
1012                 newsk = tcp_v4_syn_recv_sock(sk, skb, req, dst);
1013 
1014                 if (!newsk)
1015                         return NULL;
1016 
1017                 newtcp6sk = (struct tcp6_sock *)newsk;
1018                 inet_sk(newsk)->pinet6 = &newtcp6sk->inet6;
1019 
1020                 newinet = inet_sk(newsk);
1021                 newnp = inet6_sk(newsk);
1022                 newtp = tcp_sk(newsk);
1023 
1024                 memcpy(newnp, np, sizeof(struct ipv6_pinfo));
1025 
1026                 newnp->saddr = newsk->sk_v6_rcv_saddr;
1027 
1028                 inet_csk(newsk)->icsk_af_ops = &ipv6_mapped;
1029                 newsk->sk_backlog_rcv = tcp_v4_do_rcv;
1030 #ifdef CONFIG_TCP_MD5SIG
1031                 newtp->af_specific = &tcp_sock_ipv6_mapped_specific;
1032 #endif
1033 
1034                 newnp->ipv6_ac_list = NULL;
1035                 newnp->ipv6_fl_list = NULL;
1036                 newnp->pktoptions  = NULL;
1037                 newnp->opt         = NULL;
1038                 newnp->mcast_oif   = tcp_v6_iif(skb);
1039                 newnp->mcast_hops  = ipv6_hdr(skb)->hop_limit;
1040                 newnp->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(skb));
1041                 if (np->repflow)
1042                         newnp->flow_label = ip6_flowlabel(ipv6_hdr(skb));
1043 
1044                 /*
1045                  * No need to charge this sock to the relevant IPv6 refcnt debug socks count
1046                  * here, tcp_create_openreq_child now does this for us, see the comment in
1047                  * that function for the gory details. -acme
1048                  */
1049 
1050                 /* It is tricky place. Until this moment IPv4 tcp
1051                    worked with IPv6 icsk.icsk_af_ops.
1052                    Sync it now.
1053                  */
1054                 tcp_sync_mss(newsk, inet_csk(newsk)->icsk_pmtu_cookie);
1055 
1056                 return newsk;
1057         }
1058 
1059         ireq = inet_rsk(req);
1060 
1061         if (sk_acceptq_is_full(sk))
1062                 goto out_overflow;
1063 
1064         if (!dst) {
1065                 dst = inet6_csk_route_req(sk, &fl6, req);
1066                 if (!dst)
1067                         goto out;
1068         }
1069 
1070         newsk = tcp_create_openreq_child(sk, req, skb);
1071         if (!newsk)
1072                 goto out_nonewsk;
1073 
1074         /*
1075          * No need to charge this sock to the relevant IPv6 refcnt debug socks
1076          * count here, tcp_create_openreq_child now does this for us, see the
1077          * comment in that function for the gory details. -acme
1078          */
1079 
1080         newsk->sk_gso_type = SKB_GSO_TCPV6;
1081         __ip6_dst_store(newsk, dst, NULL, NULL);
1082         inet6_sk_rx_dst_set(newsk, skb);
1083 
1084         newtcp6sk = (struct tcp6_sock *)newsk;
1085         inet_sk(newsk)->pinet6 = &newtcp6sk->inet6;
1086 
1087         newtp = tcp_sk(newsk);
1088         newinet = inet_sk(newsk);
1089         newnp = inet6_sk(newsk);
1090 
1091         memcpy(newnp, np, sizeof(struct ipv6_pinfo));
1092 
1093         newsk->sk_v6_daddr = ireq->ir_v6_rmt_addr;
1094         newnp->saddr = ireq->ir_v6_loc_addr;
1095         newsk->sk_v6_rcv_saddr = ireq->ir_v6_loc_addr;
1096         newsk->sk_bound_dev_if = ireq->ir_iif;
1097 
1098         sk_set_txhash(newsk);
1099 
1100         /* Now IPv6 options...
1101 
1102            First: no IPv4 options.
1103          */
1104         newinet->inet_opt = NULL;
1105         newnp->ipv6_ac_list = NULL;
1106         newnp->ipv6_fl_list = NULL;
1107 
1108         /* Clone RX bits */
1109         newnp->rxopt.all = np->rxopt.all;
1110 
1111         /* Clone pktoptions received with SYN */
1112         newnp->pktoptions = NULL;
1113         if (ireq->pktopts) {
1114                 newnp->pktoptions = skb_clone(ireq->pktopts,
1115                                               sk_gfp_atomic(sk, GFP_ATOMIC));
1116                 consume_skb(ireq->pktopts);
1117                 ireq->pktopts = NULL;
1118                 if (newnp->pktoptions)
1119                         skb_set_owner_r(newnp->pktoptions, newsk);
1120         }
1121         newnp->opt        = NULL;
1122         newnp->mcast_oif  = tcp_v6_iif(skb);
1123         newnp->mcast_hops = ipv6_hdr(skb)->hop_limit;
1124         newnp->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(skb));
1125         if (np->repflow)
1126                 newnp->flow_label = ip6_flowlabel(ipv6_hdr(skb));
1127 
1128         /* Clone native IPv6 options from listening socket (if any)
1129 
1130            Yes, keeping reference count would be much more clever,
1131            but we make one more one thing there: reattach optmem
1132            to newsk.
1133          */
1134         opt = rcu_dereference(np->opt);
1135         if (opt) {
1136                 opt = ipv6_dup_options(newsk, opt);
1137                 RCU_INIT_POINTER(newnp->opt, opt);
1138         }
1139         inet_csk(newsk)->icsk_ext_hdr_len = 0;
1140         if (opt)
1141                 inet_csk(newsk)->icsk_ext_hdr_len = opt->opt_nflen +
1142                                                     opt->opt_flen;
1143 
1144         tcp_ca_openreq_child(newsk, dst);
1145 
1146         tcp_sync_mss(newsk, dst_mtu(dst));
1147         newtp->advmss = dst_metric_advmss(dst);
1148         if (tcp_sk(sk)->rx_opt.user_mss &&
1149             tcp_sk(sk)->rx_opt.user_mss < newtp->advmss)
1150                 newtp->advmss = tcp_sk(sk)->rx_opt.user_mss;
1151 
1152         tcp_initialize_rcv_mss(newsk);
1153 
1154         newinet->inet_daddr = newinet->inet_saddr = LOOPBACK4_IPV6;
1155         newinet->inet_rcv_saddr = LOOPBACK4_IPV6;
1156 
1157 #ifdef CONFIG_TCP_MD5SIG
1158         /* Copy over the MD5 key from the original socket */
1159         key = tcp_v6_md5_do_lookup(sk, &newsk->sk_v6_daddr);
1160         if (key) {
1161                 /* We're using one, so create a matching key
1162                  * on the newsk structure. If we fail to get
1163                  * memory, then we end up not copying the key
1164                  * across. Shucks.
1165                  */
1166                 tcp_md5_do_add(newsk, (union tcp_md5_addr *)&newsk->sk_v6_daddr,
1167                                AF_INET6, key->key, key->keylen,
1168                                sk_gfp_atomic(sk, GFP_ATOMIC));
1169         }
1170 #endif
1171 
1172         if (__inet_inherit_port(sk, newsk) < 0) {
1173                 inet_csk_prepare_forced_close(newsk);
1174                 tcp_done(newsk);
1175                 goto out;
1176         }
1177         __inet_hash(newsk, NULL);
1178 
1179         return newsk;
1180 
1181 out_overflow:
1182         NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
1183 out_nonewsk:
1184         dst_release(dst);
1185 out:
1186         NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
1187         return NULL;
1188 }
1189 
1190 /* The socket must have it's spinlock held when we get
1191  * here.
1192  *
1193  * We have a potential double-lock case here, so even when
1194  * doing backlog processing we use the BH locking scheme.
1195  * This is because we cannot sleep with the original spinlock
1196  * held.
1197  */
1198 static int tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb)
1199 {
1200         struct ipv6_pinfo *np = inet6_sk(sk);
1201         struct tcp_sock *tp;
1202         struct sk_buff *opt_skb = NULL;
1203 
1204         /* Imagine: socket is IPv6. IPv4 packet arrives,
1205            goes to IPv4 receive handler and backlogged.
1206            From backlog it always goes here. Kerboom...
1207            Fortunately, tcp_rcv_established and rcv_established
1208            handle them correctly, but it is not case with
1209            tcp_v6_hnd_req and tcp_v6_send_reset().   --ANK
1210          */
1211 
1212         if (skb->protocol == htons(ETH_P_IP))
1213                 return tcp_v4_do_rcv(sk, skb);
1214 
1215         if (sk_filter(sk, skb))
1216                 goto discard;
1217 
1218         /*
1219          *      socket locking is here for SMP purposes as backlog rcv
1220          *      is currently called with bh processing disabled.
1221          */
1222 
1223         /* Do Stevens' IPV6_PKTOPTIONS.
1224 
1225            Yes, guys, it is the only place in our code, where we
1226            may make it not affecting IPv4.
1227            The rest of code is protocol independent,
1228            and I do not like idea to uglify IPv4.
1229 
1230            Actually, all the idea behind IPV6_PKTOPTIONS
1231            looks not very well thought. For now we latch
1232            options, received in the last packet, enqueued
1233            by tcp. Feel free to propose better solution.
1234                                                --ANK (980728)
1235          */
1236         if (np->rxopt.all)
1237                 opt_skb = skb_clone(skb, sk_gfp_atomic(sk, GFP_ATOMIC));
1238 
1239         if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
1240                 struct dst_entry *dst = sk->sk_rx_dst;
1241 
1242                 sock_rps_save_rxhash(sk, skb);
1243                 sk_mark_napi_id(sk, skb);
1244                 if (dst) {
1245                         if (inet_sk(sk)->rx_dst_ifindex != skb->skb_iif ||
1246                             dst->ops->check(dst, np->rx_dst_cookie) == NULL) {
1247                                 dst_release(dst);
1248                                 sk->sk_rx_dst = NULL;
1249                         }
1250                 }
1251 
1252                 tcp_rcv_established(sk, skb, tcp_hdr(skb), skb->len);
1253                 if (opt_skb)
1254                         goto ipv6_pktoptions;
1255                 return 0;
1256         }
1257 
1258         if (tcp_checksum_complete(skb))
1259                 goto csum_err;
1260 
1261         if (sk->sk_state == TCP_LISTEN) {
1262                 struct sock *nsk = tcp_v6_hnd_req(sk, skb);
1263                 if (!nsk)
1264                         goto discard;
1265 
1266                 /*
1267                  * Queue it on the new socket if the new socket is active,
1268                  * otherwise we just shortcircuit this and continue with
1269                  * the new socket..
1270                  */
1271                 if (nsk != sk) {
1272                         sock_rps_save_rxhash(nsk, skb);
1273                         sk_mark_napi_id(sk, skb);
1274                         if (tcp_child_process(sk, nsk, skb))
1275                                 goto reset;
1276                         if (opt_skb)
1277                                 __kfree_skb(opt_skb);
1278                         return 0;
1279                 }
1280         } else
1281                 sock_rps_save_rxhash(sk, skb);
1282 
1283         if (tcp_rcv_state_process(sk, skb, tcp_hdr(skb), skb->len))
1284                 goto reset;
1285         if (opt_skb)
1286                 goto ipv6_pktoptions;
1287         return 0;
1288 
1289 reset:
1290         tcp_v6_send_reset(sk, skb);
1291 discard:
1292         if (opt_skb)
1293                 __kfree_skb(opt_skb);
1294         kfree_skb(skb);
1295         return 0;
1296 csum_err:
1297         TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_CSUMERRORS);
1298         TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_INERRS);
1299         goto discard;
1300 
1301 
1302 ipv6_pktoptions:
1303         /* Do you ask, what is it?
1304 
1305            1. skb was enqueued by tcp.
1306            2. skb is added to tail of read queue, rather than out of order.
1307            3. socket is not in passive state.
1308            4. Finally, it really contains options, which user wants to receive.
1309          */
1310         tp = tcp_sk(sk);
1311         if (TCP_SKB_CB(opt_skb)->end_seq == tp->rcv_nxt &&
1312             !((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN))) {
1313                 if (np->rxopt.bits.rxinfo || np->rxopt.bits.rxoinfo)
1314                         np->mcast_oif = tcp_v6_iif(opt_skb);
1315                 if (np->rxopt.bits.rxhlim || np->rxopt.bits.rxohlim)
1316                         np->mcast_hops = ipv6_hdr(opt_skb)->hop_limit;
1317                 if (np->rxopt.bits.rxflow || np->rxopt.bits.rxtclass)
1318                         np->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(opt_skb));
1319                 if (np->repflow)
1320                         np->flow_label = ip6_flowlabel(ipv6_hdr(opt_skb));
1321                 if (ipv6_opt_accepted(sk, opt_skb, &TCP_SKB_CB(opt_skb)->header.h6)) {
1322                         skb_set_owner_r(opt_skb, sk);
1323                         opt_skb = xchg(&np->pktoptions, opt_skb);
1324                 } else {
1325                         __kfree_skb(opt_skb);
1326                         opt_skb = xchg(&np->pktoptions, NULL);
1327                 }
1328         }
1329 
1330         kfree_skb(opt_skb);
1331         return 0;
1332 }
1333 
1334 static void tcp_v6_fill_cb(struct sk_buff *skb, const struct ipv6hdr *hdr,
1335                            const struct tcphdr *th)
1336 {
1337         /* This is tricky: we move IP6CB at its correct location into
1338          * TCP_SKB_CB(). It must be done after xfrm6_policy_check(), because
1339          * _decode_session6() uses IP6CB().
1340          * barrier() makes sure compiler won't play aliasing games.
1341          */
1342         memmove(&TCP_SKB_CB(skb)->header.h6, IP6CB(skb),
1343                 sizeof(struct inet6_skb_parm));
1344         barrier();
1345 
1346         TCP_SKB_CB(skb)->seq = ntohl(th->seq);
1347         TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
1348                                     skb->len - th->doff*4);
1349         TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
1350         TCP_SKB_CB(skb)->tcp_flags = tcp_flag_byte(th);
1351         TCP_SKB_CB(skb)->tcp_tw_isn = 0;
1352         TCP_SKB_CB(skb)->ip_dsfield = ipv6_get_dsfield(hdr);
1353         TCP_SKB_CB(skb)->sacked = 0;
1354 }
1355 
1356 static void tcp_v6_restore_cb(struct sk_buff *skb)
1357 {
1358         /* We need to move header back to the beginning if xfrm6_policy_check()
1359          * and tcp_v6_fill_cb() are going to be called again.
1360          */
1361         memmove(IP6CB(skb), &TCP_SKB_CB(skb)->header.h6,
1362                 sizeof(struct inet6_skb_parm));
1363 }
1364 
1365 static int tcp_v6_rcv(struct sk_buff *skb)
1366 {
1367         const struct tcphdr *th;
1368         const struct ipv6hdr *hdr;
1369         struct sock *sk;
1370         int ret;
1371         struct net *net = dev_net(skb->dev);
1372 
1373         if (skb->pkt_type != PACKET_HOST)
1374                 goto discard_it;
1375 
1376         /*
1377          *      Count it even if it's bad.
1378          */
1379         TCP_INC_STATS_BH(net, TCP_MIB_INSEGS);
1380 
1381         if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
1382                 goto discard_it;
1383 
1384         th = tcp_hdr(skb);
1385 
1386         if (th->doff < sizeof(struct tcphdr)/4)
1387                 goto bad_packet;
1388         if (!pskb_may_pull(skb, th->doff*4))
1389                 goto discard_it;
1390 
1391         if (skb_checksum_init(skb, IPPROTO_TCP, ip6_compute_pseudo))
1392                 goto csum_error;
1393 
1394         th = tcp_hdr(skb);
1395         hdr = ipv6_hdr(skb);
1396 
1397         sk = __inet6_lookup_skb(&tcp_hashinfo, skb, th->source, th->dest,
1398                                 inet6_iif(skb));
1399         if (!sk)
1400                 goto no_tcp_socket;
1401 
1402 process:
1403         if (sk->sk_state == TCP_TIME_WAIT)
1404                 goto do_time_wait;
1405 
1406         if (hdr->hop_limit < inet6_sk(sk)->min_hopcount) {
1407                 NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP);
1408                 goto discard_and_relse;
1409         }
1410 
1411         if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb))
1412                 goto discard_and_relse;
1413 
1414         tcp_v6_fill_cb(skb, hdr, th);
1415 
1416 #ifdef CONFIG_TCP_MD5SIG
1417         if (tcp_v6_inbound_md5_hash(sk, skb))
1418                 goto discard_and_relse;
1419 #endif
1420 
1421         if (sk_filter(sk, skb))
1422                 goto discard_and_relse;
1423 
1424         sk_incoming_cpu_update(sk);
1425         skb->dev = NULL;
1426 
1427         bh_lock_sock_nested(sk);
1428         tcp_sk(sk)->segs_in += max_t(u16, 1, skb_shinfo(skb)->gso_segs);
1429         ret = 0;
1430         if (!sock_owned_by_user(sk)) {
1431                 if (!tcp_prequeue(sk, skb))
1432                         ret = tcp_v6_do_rcv(sk, skb);
1433         } else if (unlikely(sk_add_backlog(sk, skb,
1434                                            sk->sk_rcvbuf + sk->sk_sndbuf))) {
1435                 bh_unlock_sock(sk);
1436                 NET_INC_STATS_BH(net, LINUX_MIB_TCPBACKLOGDROP);
1437                 goto discard_and_relse;
1438         }
1439         bh_unlock_sock(sk);
1440 
1441         sock_put(sk);
1442         return ret ? -1 : 0;
1443 
1444 no_tcp_socket:
1445         if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb))
1446                 goto discard_it;
1447 
1448         tcp_v6_fill_cb(skb, hdr, th);
1449 
1450         if (tcp_checksum_complete(skb)) {
1451 csum_error:
1452                 TCP_INC_STATS_BH(net, TCP_MIB_CSUMERRORS);
1453 bad_packet:
1454                 TCP_INC_STATS_BH(net, TCP_MIB_INERRS);
1455         } else {
1456                 tcp_v6_send_reset(NULL, skb);
1457         }
1458 
1459 discard_it:
1460         kfree_skb(skb);
1461         return 0;
1462 
1463 discard_and_relse:
1464         sock_put(sk);
1465         goto discard_it;
1466 
1467 do_time_wait:
1468         if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
1469                 inet_twsk_put(inet_twsk(sk));
1470                 goto discard_it;
1471         }
1472 
1473         tcp_v6_fill_cb(skb, hdr, th);
1474 
1475         if (tcp_checksum_complete(skb)) {
1476                 inet_twsk_put(inet_twsk(sk));
1477                 goto csum_error;
1478         }
1479 
1480         switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) {
1481         case TCP_TW_SYN:
1482         {
1483                 struct sock *sk2;
1484 
1485                 sk2 = inet6_lookup_listener(dev_net(skb->dev), &tcp_hashinfo,
1486                                             &ipv6_hdr(skb)->saddr, th->source,
1487                                             &ipv6_hdr(skb)->daddr,
1488                                             ntohs(th->dest), tcp_v6_iif(skb));
1489                 if (sk2) {
1490                         struct inet_timewait_sock *tw = inet_twsk(sk);
1491                         inet_twsk_deschedule_put(tw);
1492                         sk = sk2;
1493                         tcp_v6_restore_cb(skb);
1494                         goto process;
1495                 }
1496                 /* Fall through to ACK */
1497         }
1498         case TCP_TW_ACK:
1499                 tcp_v6_timewait_ack(sk, skb);
1500                 break;
1501         case TCP_TW_RST:
1502                 tcp_v6_restore_cb(skb);
1503                 goto no_tcp_socket;
1504         case TCP_TW_SUCCESS:
1505                 ;
1506         }
1507         goto discard_it;
1508 }
1509 
1510 static void tcp_v6_early_demux(struct sk_buff *skb)
1511 {
1512         const struct ipv6hdr *hdr;
1513         const struct tcphdr *th;
1514         struct sock *sk;
1515 
1516         if (skb->pkt_type != PACKET_HOST)
1517                 return;
1518 
1519         if (!pskb_may_pull(skb, skb_transport_offset(skb) + sizeof(struct tcphdr)))
1520                 return;
1521 
1522         hdr = ipv6_hdr(skb);
1523         th = tcp_hdr(skb);
1524 
1525         if (th->doff < sizeof(struct tcphdr) / 4)
1526                 return;
1527 
1528         /* Note : We use inet6_iif() here, not tcp_v6_iif() */
1529         sk = __inet6_lookup_established(dev_net(skb->dev), &tcp_hashinfo,
1530                                         &hdr->saddr, th->source,
1531                                         &hdr->daddr, ntohs(th->dest),
1532                                         inet6_iif(skb));
1533         if (sk) {
1534                 skb->sk = sk;
1535                 skb->destructor = sock_edemux;
1536                 if (sk_fullsock(sk)) {
1537                         struct dst_entry *dst = READ_ONCE(sk->sk_rx_dst);
1538 
1539                         if (dst)
1540                                 dst = dst_check(dst, inet6_sk(sk)->rx_dst_cookie);
1541                         if (dst &&
1542                             inet_sk(sk)->rx_dst_ifindex == skb->skb_iif)
1543                                 skb_dst_set_noref(skb, dst);
1544                 }
1545         }
1546 }
1547 
1548 static struct timewait_sock_ops tcp6_timewait_sock_ops = {
1549         .twsk_obj_size  = sizeof(struct tcp6_timewait_sock),
1550         .twsk_unique    = tcp_twsk_unique,
1551         .twsk_destructor = tcp_twsk_destructor,
1552 };
1553 
1554 static const struct inet_connection_sock_af_ops ipv6_specific = {
1555         .queue_xmit        = inet6_csk_xmit,
1556         .send_check        = tcp_v6_send_check,
1557         .rebuild_header    = inet6_sk_rebuild_header,
1558         .sk_rx_dst_set     = inet6_sk_rx_dst_set,
1559         .conn_request      = tcp_v6_conn_request,
1560         .syn_recv_sock     = tcp_v6_syn_recv_sock,
1561         .net_header_len    = sizeof(struct ipv6hdr),
1562         .net_frag_header_len = sizeof(struct frag_hdr),
1563         .setsockopt        = ipv6_setsockopt,
1564         .getsockopt        = ipv6_getsockopt,
1565         .addr2sockaddr     = inet6_csk_addr2sockaddr,
1566         .sockaddr_len      = sizeof(struct sockaddr_in6),
1567         .bind_conflict     = inet6_csk_bind_conflict,
1568 #ifdef CONFIG_COMPAT
1569         .compat_setsockopt = compat_ipv6_setsockopt,
1570         .compat_getsockopt = compat_ipv6_getsockopt,
1571 #endif
1572         .mtu_reduced       = tcp_v6_mtu_reduced,
1573 };
1574 
1575 #ifdef CONFIG_TCP_MD5SIG
1576 static const struct tcp_sock_af_ops tcp_sock_ipv6_specific = {
1577         .md5_lookup     =       tcp_v6_md5_lookup,
1578         .calc_md5_hash  =       tcp_v6_md5_hash_skb,
1579         .md5_parse      =       tcp_v6_parse_md5_keys,
1580 };
1581 #endif
1582 
1583 /*
1584  *      TCP over IPv4 via INET6 API
1585  */
1586 static const struct inet_connection_sock_af_ops ipv6_mapped = {
1587         .queue_xmit        = ip_queue_xmit,
1588         .send_check        = tcp_v4_send_check,
1589         .rebuild_header    = inet_sk_rebuild_header,
1590         .sk_rx_dst_set     = inet_sk_rx_dst_set,
1591         .conn_request      = tcp_v6_conn_request,
1592         .syn_recv_sock     = tcp_v6_syn_recv_sock,
1593         .net_header_len    = sizeof(struct iphdr),
1594         .setsockopt        = ipv6_setsockopt,
1595         .getsockopt        = ipv6_getsockopt,
1596         .addr2sockaddr     = inet6_csk_addr2sockaddr,
1597         .sockaddr_len      = sizeof(struct sockaddr_in6),
1598         .bind_conflict     = inet6_csk_bind_conflict,
1599 #ifdef CONFIG_COMPAT
1600         .compat_setsockopt = compat_ipv6_setsockopt,
1601         .compat_getsockopt = compat_ipv6_getsockopt,
1602 #endif
1603         .mtu_reduced       = tcp_v4_mtu_reduced,
1604 };
1605 
1606 #ifdef CONFIG_TCP_MD5SIG
1607 static const struct tcp_sock_af_ops tcp_sock_ipv6_mapped_specific = {
1608         .md5_lookup     =       tcp_v4_md5_lookup,
1609         .calc_md5_hash  =       tcp_v4_md5_hash_skb,
1610         .md5_parse      =       tcp_v6_parse_md5_keys,
1611 };
1612 #endif
1613 
1614 /* NOTE: A lot of things set to zero explicitly by call to
1615  *       sk_alloc() so need not be done here.
1616  */
1617 static int tcp_v6_init_sock(struct sock *sk)
1618 {
1619         struct inet_connection_sock *icsk = inet_csk(sk);
1620 
1621         tcp_init_sock(sk);
1622 
1623         icsk->icsk_af_ops = &ipv6_specific;
1624 
1625 #ifdef CONFIG_TCP_MD5SIG
1626         tcp_sk(sk)->af_specific = &tcp_sock_ipv6_specific;
1627 #endif
1628 
1629         return 0;
1630 }
1631 
1632 static void tcp_v6_destroy_sock(struct sock *sk)
1633 {
1634         tcp_v4_destroy_sock(sk);
1635         inet6_destroy_sock(sk);
1636 }
1637 
1638 #ifdef CONFIG_PROC_FS
1639 /* Proc filesystem TCPv6 sock list dumping. */
1640 static void get_openreq6(struct seq_file *seq,
1641                          struct request_sock *req, int i, kuid_t uid)
1642 {
1643         long ttd = req->rsk_timer.expires - jiffies;
1644         const struct in6_addr *src = &inet_rsk(req)->ir_v6_loc_addr;
1645         const struct in6_addr *dest = &inet_rsk(req)->ir_v6_rmt_addr;
1646 
1647         if (ttd < 0)
1648                 ttd = 0;
1649 
1650         seq_printf(seq,
1651                    "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
1652                    "%02X %08X:%08X %02X:%08lX %08X %5u %8d %d %d %pK\n",
1653                    i,
1654                    src->s6_addr32[0], src->s6_addr32[1],
1655                    src->s6_addr32[2], src->s6_addr32[3],
1656                    inet_rsk(req)->ir_num,
1657                    dest->s6_addr32[0], dest->s6_addr32[1],
1658                    dest->s6_addr32[2], dest->s6_addr32[3],
1659                    ntohs(inet_rsk(req)->ir_rmt_port),
1660                    TCP_SYN_RECV,
1661                    0, 0, /* could print option size, but that is af dependent. */
1662                    1,   /* timers active (only the expire timer) */
1663                    jiffies_to_clock_t(ttd),
1664                    req->num_timeout,
1665                    from_kuid_munged(seq_user_ns(seq), uid),
1666                    0,  /* non standard timer */
1667                    0, /* open_requests have no inode */
1668                    0, req);
1669 }
1670 
1671 static void get_tcp6_sock(struct seq_file *seq, struct sock *sp, int i)
1672 {
1673         const struct in6_addr *dest, *src;
1674         __u16 destp, srcp;
1675         int timer_active;
1676         unsigned long timer_expires;
1677         const struct inet_sock *inet = inet_sk(sp);
1678         const struct tcp_sock *tp = tcp_sk(sp);
1679         const struct inet_connection_sock *icsk = inet_csk(sp);
1680         struct fastopen_queue *fastopenq = icsk->icsk_accept_queue.fastopenq;
1681 
1682         dest  = &sp->sk_v6_daddr;
1683         src   = &sp->sk_v6_rcv_saddr;
1684         destp = ntohs(inet->inet_dport);
1685         srcp  = ntohs(inet->inet_sport);
1686 
1687         if (icsk->icsk_pending == ICSK_TIME_RETRANS) {
1688                 timer_active    = 1;
1689                 timer_expires   = icsk->icsk_timeout;
1690         } else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
1691                 timer_active    = 4;
1692                 timer_expires   = icsk->icsk_timeout;
1693         } else if (timer_pending(&sp->sk_timer)) {
1694                 timer_active    = 2;
1695                 timer_expires   = sp->sk_timer.expires;
1696         } else {
1697                 timer_active    = 0;
1698                 timer_expires = jiffies;
1699         }
1700 
1701         seq_printf(seq,
1702                    "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
1703                    "%02X %08X:%08X %02X:%08lX %08X %5u %8d %lu %d %pK %lu %lu %u %u %d\n",
1704                    i,
1705                    src->s6_addr32[0], src->s6_addr32[1],
1706                    src->s6_addr32[2], src->s6_addr32[3], srcp,
1707                    dest->s6_addr32[0], dest->s6_addr32[1],
1708                    dest->s6_addr32[2], dest->s6_addr32[3], destp,
1709                    sp->sk_state,
1710                    tp->write_seq-tp->snd_una,
1711                    (sp->sk_state == TCP_LISTEN) ? sp->sk_ack_backlog : (tp->rcv_nxt - tp->copied_seq),
1712                    timer_active,
1713                    jiffies_delta_to_clock_t(timer_expires - jiffies),
1714                    icsk->icsk_retransmits,
1715                    from_kuid_munged(seq_user_ns(seq), sock_i_uid(sp)),
1716                    icsk->icsk_probes_out,
1717                    sock_i_ino(sp),
1718                    atomic_read(&sp->sk_refcnt), sp,
1719                    jiffies_to_clock_t(icsk->icsk_rto),
1720                    jiffies_to_clock_t(icsk->icsk_ack.ato),
1721                    (icsk->icsk_ack.quick << 1) | icsk->icsk_ack.pingpong,
1722                    tp->snd_cwnd,
1723                    sp->sk_state == TCP_LISTEN ?
1724                         (fastopenq ? fastopenq->max_qlen : 0) :
1725                         (tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh)
1726                    );
1727 }
1728 
1729 static void get_timewait6_sock(struct seq_file *seq,
1730                                struct inet_timewait_sock *tw, int i)
1731 {
1732         long delta = tw->tw_timer.expires - jiffies;
1733         const struct in6_addr *dest, *src;
1734         __u16 destp, srcp;
1735 
1736         dest = &tw->tw_v6_daddr;
1737         src  = &tw->tw_v6_rcv_saddr;
1738         destp = ntohs(tw->tw_dport);
1739         srcp  = ntohs(tw->tw_sport);
1740 
1741         seq_printf(seq,
1742                    "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
1743                    "%02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK\n",
1744                    i,
1745                    src->s6_addr32[0], src->s6_addr32[1],
1746                    src->s6_addr32[2], src->s6_addr32[3], srcp,
1747                    dest->s6_addr32[0], dest->s6_addr32[1],
1748                    dest->s6_addr32[2], dest->s6_addr32[3], destp,
1749                    tw->tw_substate, 0, 0,
1750                    3, jiffies_delta_to_clock_t(delta), 0, 0, 0, 0,
1751                    atomic_read(&tw->tw_refcnt), tw);
1752 }
1753 
1754 static int tcp6_seq_show(struct seq_file *seq, void *v)
1755 {
1756         struct tcp_iter_state *st;
1757         struct sock *sk = v;
1758 
1759         if (v == SEQ_START_TOKEN) {
1760                 seq_puts(seq,
1761                          "  sl  "
1762                          "local_address                         "
1763                          "remote_address                        "
1764                          "st tx_queue rx_queue tr tm->when retrnsmt"
1765                          "   uid  timeout inode\n");
1766                 goto out;
1767         }
1768         st = seq->private;
1769 
1770         switch (st->state) {
1771         case TCP_SEQ_STATE_LISTENING:
1772         case TCP_SEQ_STATE_ESTABLISHED:
1773                 if (sk->sk_state == TCP_TIME_WAIT)
1774                         get_timewait6_sock(seq, v, st->num);
1775                 else
1776                         get_tcp6_sock(seq, v, st->num);
1777                 break;
1778         case TCP_SEQ_STATE_OPENREQ:
1779                 get_openreq6(seq, v, st->num, st->uid);
1780                 break;
1781         }
1782 out:
1783         return 0;
1784 }
1785 
1786 static const struct file_operations tcp6_afinfo_seq_fops = {
1787         .owner   = THIS_MODULE,
1788         .open    = tcp_seq_open,
1789         .read    = seq_read,
1790         .llseek  = seq_lseek,
1791         .release = seq_release_net
1792 };
1793 
1794 static struct tcp_seq_afinfo tcp6_seq_afinfo = {
1795         .name           = "tcp6",
1796         .family         = AF_INET6,
1797         .seq_fops       = &tcp6_afinfo_seq_fops,
1798         .seq_ops        = {
1799                 .show           = tcp6_seq_show,
1800         },
1801 };
1802 
1803 int __net_init tcp6_proc_init(struct net *net)
1804 {
1805         return tcp_proc_register(net, &tcp6_seq_afinfo);
1806 }
1807 
1808 void tcp6_proc_exit(struct net *net)
1809 {
1810         tcp_proc_unregister(net, &tcp6_seq_afinfo);
1811 }
1812 #endif
1813 
1814 static void tcp_v6_clear_sk(struct sock *sk, int size)
1815 {
1816         struct inet_sock *inet = inet_sk(sk);
1817 
1818         /* we do not want to clear pinet6 field, because of RCU lookups */
1819         sk_prot_clear_nulls(sk, offsetof(struct inet_sock, pinet6));
1820 
1821         size -= offsetof(struct inet_sock, pinet6) + sizeof(inet->pinet6);
1822         memset(&inet->pinet6 + 1, 0, size);
1823 }
1824 
1825 struct proto tcpv6_prot = {
1826         .name                   = "TCPv6",
1827         .owner                  = THIS_MODULE,
1828         .close                  = tcp_close,
1829         .connect                = tcp_v6_connect,
1830         .disconnect             = tcp_disconnect,
1831         .accept                 = inet_csk_accept,
1832         .ioctl                  = tcp_ioctl,
1833         .init                   = tcp_v6_init_sock,
1834         .destroy                = tcp_v6_destroy_sock,
1835         .shutdown               = tcp_shutdown,
1836         .setsockopt             = tcp_setsockopt,
1837         .getsockopt             = tcp_getsockopt,
1838         .recvmsg                = tcp_recvmsg,
1839         .sendmsg                = tcp_sendmsg,
1840         .sendpage               = tcp_sendpage,
1841         .backlog_rcv            = tcp_v6_do_rcv,
1842         .release_cb             = tcp_release_cb,
1843         .hash                   = inet_hash,
1844         .unhash                 = inet_unhash,
1845         .get_port               = inet_csk_get_port,
1846         .enter_memory_pressure  = tcp_enter_memory_pressure,
1847         .stream_memory_free     = tcp_stream_memory_free,
1848         .sockets_allocated      = &tcp_sockets_allocated,
1849         .memory_allocated       = &tcp_memory_allocated,
1850         .memory_pressure        = &tcp_memory_pressure,
1851         .orphan_count           = &tcp_orphan_count,
1852         .sysctl_mem             = sysctl_tcp_mem,
1853         .sysctl_wmem            = sysctl_tcp_wmem,
1854         .sysctl_rmem            = sysctl_tcp_rmem,
1855         .max_header             = MAX_TCP_HEADER,
1856         .obj_size               = sizeof(struct tcp6_sock),
1857         .slab_flags             = SLAB_DESTROY_BY_RCU,
1858         .twsk_prot              = &tcp6_timewait_sock_ops,
1859         .rsk_prot               = &tcp6_request_sock_ops,
1860         .h.hashinfo             = &tcp_hashinfo,
1861         .no_autobind            = true,
1862 #ifdef CONFIG_COMPAT
1863         .compat_setsockopt      = compat_tcp_setsockopt,
1864         .compat_getsockopt      = compat_tcp_getsockopt,
1865 #endif
1866 #ifdef CONFIG_MEMCG_KMEM
1867         .proto_cgroup           = tcp_proto_cgroup,
1868 #endif
1869         .clear_sk               = tcp_v6_clear_sk,
1870 };
1871 
1872 static const struct inet6_protocol tcpv6_protocol = {
1873         .early_demux    =       tcp_v6_early_demux,
1874         .handler        =       tcp_v6_rcv,
1875         .err_handler    =       tcp_v6_err,
1876         .flags          =       INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
1877 };
1878 
1879 static struct inet_protosw tcpv6_protosw = {
1880         .type           =       SOCK_STREAM,
1881         .protocol       =       IPPROTO_TCP,
1882         .prot           =       &tcpv6_prot,
1883         .ops            =       &inet6_stream_ops,
1884         .flags          =       INET_PROTOSW_PERMANENT |
1885                                 INET_PROTOSW_ICSK,
1886 };
1887 
1888 static int __net_init tcpv6_net_init(struct net *net)
1889 {
1890         return inet_ctl_sock_create(&net->ipv6.tcp_sk, PF_INET6,
1891                                     SOCK_RAW, IPPROTO_TCP, net);
1892 }
1893 
1894 static void __net_exit tcpv6_net_exit(struct net *net)
1895 {
1896         inet_ctl_sock_destroy(net->ipv6.tcp_sk);
1897 }
1898 
1899 static void __net_exit tcpv6_net_exit_batch(struct list_head *net_exit_list)
1900 {
1901         inet_twsk_purge(&tcp_hashinfo, &tcp_death_row, AF_INET6);
1902 }
1903 
1904 static struct pernet_operations tcpv6_net_ops = {
1905         .init       = tcpv6_net_init,
1906         .exit       = tcpv6_net_exit,
1907         .exit_batch = tcpv6_net_exit_batch,
1908 };
1909 
1910 int __init tcpv6_init(void)
1911 {
1912         int ret;
1913 
1914         ret = inet6_add_protocol(&tcpv6_protocol, IPPROTO_TCP);
1915         if (ret)
1916                 goto out;
1917 
1918         /* register inet6 protocol */
1919         ret = inet6_register_protosw(&tcpv6_protosw);
1920         if (ret)
1921                 goto out_tcpv6_protocol;
1922 
1923         ret = register_pernet_subsys(&tcpv6_net_ops);
1924         if (ret)
1925                 goto out_tcpv6_protosw;
1926 out:
1927         return ret;
1928 
1929 out_tcpv6_protosw:
1930         inet6_unregister_protosw(&tcpv6_protosw);
1931 out_tcpv6_protocol:
1932         inet6_del_protocol(&tcpv6_protocol, IPPROTO_TCP);
1933         goto out;
1934 }
1935 
1936 void tcpv6_exit(void)
1937 {
1938         unregister_pernet_subsys(&tcpv6_net_ops);
1939         inet6_unregister_protosw(&tcpv6_protosw);
1940         inet6_del_protocol(&tcpv6_protocol, IPPROTO_TCP);
1941 }
1942 

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