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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/busy_poll.h>
 65 
 66 #include <linux/proc_fs.h>
 67 #include <linux/seq_file.h>
 68 
 69 #include <linux/crypto.h>
 70 #include <linux/scatterlist.h>
 71 
 72 static void     tcp_v6_send_reset(const struct sock *sk, struct sk_buff *skb);
 73 static void     tcp_v6_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb,
 74                                       struct request_sock *req);
 75 
 76 static int      tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb);
 77 
 78 static const struct inet_connection_sock_af_ops ipv6_mapped;
 79 static const struct inet_connection_sock_af_ops ipv6_specific;
 80 #ifdef CONFIG_TCP_MD5SIG
 81 static const struct tcp_sock_af_ops tcp_sock_ipv6_specific;
 82 static const struct tcp_sock_af_ops tcp_sock_ipv6_mapped_specific;
 83 #else
 84 static struct tcp_md5sig_key *tcp_v6_md5_do_lookup(const struct sock *sk,
 85                                                    const struct in6_addr *addr)
 86 {
 87         return NULL;
 88 }
 89 #endif
 90 
 91 static void inet6_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb)
 92 {
 93         struct dst_entry *dst = skb_dst(skb);
 94 
 95         if (dst && dst_hold_safe(dst)) {
 96                 const struct rt6_info *rt = (const struct rt6_info *)dst;
 97 
 98                 sk->sk_rx_dst = dst;
 99                 inet_sk(sk)->rx_dst_ifindex = skb->skb_iif;
100                 inet6_sk(sk)->rx_dst_cookie = rt6_get_cookie(rt);
101         }
102 }
103 
104 static __u32 tcp_v6_init_sequence(const struct sk_buff *skb)
105 {
106         return secure_tcpv6_sequence_number(ipv6_hdr(skb)->daddr.s6_addr32,
107                                             ipv6_hdr(skb)->saddr.s6_addr32,
108                                             tcp_hdr(skb)->dest,
109                                             tcp_hdr(skb)->source);
110 }
111 
112 static int tcp_v6_connect(struct sock *sk, struct sockaddr *uaddr,
113                           int addr_len)
114 {
115         struct sockaddr_in6 *usin = (struct sockaddr_in6 *) uaddr;
116         struct inet_sock *inet = inet_sk(sk);
117         struct inet_connection_sock *icsk = inet_csk(sk);
118         struct ipv6_pinfo *np = inet6_sk(sk);
119         struct tcp_sock *tp = tcp_sk(sk);
120         struct in6_addr *saddr = NULL, *final_p, final;
121         struct ipv6_txoptions *opt;
122         struct flowi6 fl6;
123         struct dst_entry *dst;
124         int addr_type;
125         int err;
126 
127         if (addr_len < SIN6_LEN_RFC2133)
128                 return -EINVAL;
129 
130         if (usin->sin6_family != AF_INET6)
131                 return -EAFNOSUPPORT;
132 
133         memset(&fl6, 0, sizeof(fl6));
134 
135         if (np->sndflow) {
136                 fl6.flowlabel = usin->sin6_flowinfo&IPV6_FLOWINFO_MASK;
137                 IP6_ECN_flow_init(fl6.flowlabel);
138                 if (fl6.flowlabel&IPV6_FLOWLABEL_MASK) {
139                         struct ip6_flowlabel *flowlabel;
140                         flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
141                         if (!flowlabel)
142                                 return -EINVAL;
143                         fl6_sock_release(flowlabel);
144                 }
145         }
146 
147         /*
148          *      connect() to INADDR_ANY means loopback (BSD'ism).
149          */
150 
151         if (ipv6_addr_any(&usin->sin6_addr))
152                 usin->sin6_addr.s6_addr[15] = 0x1;
153 
154         addr_type = ipv6_addr_type(&usin->sin6_addr);
155 
156         if (addr_type & IPV6_ADDR_MULTICAST)
157                 return -ENETUNREACH;
158 
159         if (addr_type&IPV6_ADDR_LINKLOCAL) {
160                 if (addr_len >= sizeof(struct sockaddr_in6) &&
161                     usin->sin6_scope_id) {
162                         /* If interface is set while binding, indices
163                          * must coincide.
164                          */
165                         if (sk->sk_bound_dev_if &&
166                             sk->sk_bound_dev_if != usin->sin6_scope_id)
167                                 return -EINVAL;
168 
169                         sk->sk_bound_dev_if = usin->sin6_scope_id;
170                 }
171 
172                 /* Connect to link-local address requires an interface */
173                 if (!sk->sk_bound_dev_if)
174                         return -EINVAL;
175         }
176 
177         if (tp->rx_opt.ts_recent_stamp &&
178             !ipv6_addr_equal(&sk->sk_v6_daddr, &usin->sin6_addr)) {
179                 tp->rx_opt.ts_recent = 0;
180                 tp->rx_opt.ts_recent_stamp = 0;
181                 tp->write_seq = 0;
182         }
183 
184         sk->sk_v6_daddr = usin->sin6_addr;
185         np->flow_label = fl6.flowlabel;
186 
187         /*
188          *      TCP over IPv4
189          */
190 
191         if (addr_type == IPV6_ADDR_MAPPED) {
192                 u32 exthdrlen = icsk->icsk_ext_hdr_len;
193                 struct sockaddr_in sin;
194 
195                 SOCK_DEBUG(sk, "connect: ipv4 mapped\n");
196 
197                 if (__ipv6_only_sock(sk))
198                         return -ENETUNREACH;
199 
200                 sin.sin_family = AF_INET;
201                 sin.sin_port = usin->sin6_port;
202                 sin.sin_addr.s_addr = usin->sin6_addr.s6_addr32[3];
203 
204                 icsk->icsk_af_ops = &ipv6_mapped;
205                 sk->sk_backlog_rcv = tcp_v4_do_rcv;
206 #ifdef CONFIG_TCP_MD5SIG
207                 tp->af_specific = &tcp_sock_ipv6_mapped_specific;
208 #endif
209 
210                 err = tcp_v4_connect(sk, (struct sockaddr *)&sin, sizeof(sin));
211 
212                 if (err) {
213                         icsk->icsk_ext_hdr_len = exthdrlen;
214                         icsk->icsk_af_ops = &ipv6_specific;
215                         sk->sk_backlog_rcv = tcp_v6_do_rcv;
216 #ifdef CONFIG_TCP_MD5SIG
217                         tp->af_specific = &tcp_sock_ipv6_specific;
218 #endif
219                         goto failure;
220                 }
221                 np->saddr = sk->sk_v6_rcv_saddr;
222 
223                 return err;
224         }
225 
226         if (!ipv6_addr_any(&sk->sk_v6_rcv_saddr))
227                 saddr = &sk->sk_v6_rcv_saddr;
228 
229         fl6.flowi6_proto = IPPROTO_TCP;
230         fl6.daddr = sk->sk_v6_daddr;
231         fl6.saddr = saddr ? *saddr : np->saddr;
232         fl6.flowi6_oif = sk->sk_bound_dev_if;
233         fl6.flowi6_mark = sk->sk_mark;
234         fl6.fl6_dport = usin->sin6_port;
235         fl6.fl6_sport = inet->inet_sport;
236 
237         opt = rcu_dereference_protected(np->opt, sock_owned_by_user(sk));
238         final_p = fl6_update_dst(&fl6, opt, &final);
239 
240         security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));
241 
242         dst = ip6_dst_lookup_flow(sk, &fl6, final_p);
243         if (IS_ERR(dst)) {
244                 err = PTR_ERR(dst);
245                 goto failure;
246         }
247 
248         if (!saddr) {
249                 saddr = &fl6.saddr;
250                 sk->sk_v6_rcv_saddr = *saddr;
251         }
252 
253         /* set the source address */
254         np->saddr = *saddr;
255         inet->inet_rcv_saddr = LOOPBACK4_IPV6;
256 
257         sk->sk_gso_type = SKB_GSO_TCPV6;
258         ip6_dst_store(sk, dst, NULL, NULL);
259 
260         if (tcp_death_row.sysctl_tw_recycle &&
261             !tp->rx_opt.ts_recent_stamp &&
262             ipv6_addr_equal(&fl6.daddr, &sk->sk_v6_daddr))
263                 tcp_fetch_timewait_stamp(sk, dst);
264 
265         icsk->icsk_ext_hdr_len = 0;
266         if (opt)
267                 icsk->icsk_ext_hdr_len = opt->opt_flen +
268                                          opt->opt_nflen;
269 
270         tp->rx_opt.mss_clamp = IPV6_MIN_MTU - sizeof(struct tcphdr) - sizeof(struct ipv6hdr);
271 
272         inet->inet_dport = usin->sin6_port;
273 
274         tcp_set_state(sk, TCP_SYN_SENT);
275         err = inet6_hash_connect(&tcp_death_row, sk);
276         if (err)
277                 goto late_failure;
278 
279         sk_set_txhash(sk);
280 
281         if (!tp->write_seq && likely(!tp->repair))
282                 tp->write_seq = secure_tcpv6_sequence_number(np->saddr.s6_addr32,
283                                                              sk->sk_v6_daddr.s6_addr32,
284                                                              inet->inet_sport,
285                                                              inet->inet_dport);
286 
287         err = tcp_connect(sk);
288         if (err)
289                 goto late_failure;
290 
291         return 0;
292 
293 late_failure:
294         tcp_set_state(sk, TCP_CLOSE);
295         __sk_dst_reset(sk);
296 failure:
297         inet->inet_dport = 0;
298         sk->sk_route_caps = 0;
299         return err;
300 }
301 
302 static void tcp_v6_mtu_reduced(struct sock *sk)
303 {
304         struct dst_entry *dst;
305 
306         if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE))
307                 return;
308 
309         dst = inet6_csk_update_pmtu(sk, tcp_sk(sk)->mtu_info);
310         if (!dst)
311                 return;
312 
313         if (inet_csk(sk)->icsk_pmtu_cookie > dst_mtu(dst)) {
314                 tcp_sync_mss(sk, dst_mtu(dst));
315                 tcp_simple_retransmit(sk);
316         }
317 }
318 
319 static void tcp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
320                 u8 type, u8 code, int offset, __be32 info)
321 {
322         const struct ipv6hdr *hdr = (const struct ipv6hdr *)skb->data;
323         const struct tcphdr *th = (struct tcphdr *)(skb->data+offset);
324         struct net *net = dev_net(skb->dev);
325         struct request_sock *fastopen;
326         struct ipv6_pinfo *np;
327         struct tcp_sock *tp;
328         __u32 seq, snd_una;
329         struct sock *sk;
330         bool fatal;
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         fatal = icmpv6_err_convert(type, code, &err);
350         if (sk->sk_state == TCP_NEW_SYN_RECV)
351                 return tcp_req_err(sk, seq, fatal);
352 
353         bh_lock_sock(sk);
354         if (sock_owned_by_user(sk) && type != ICMPV6_PKT_TOOBIG)
355                 NET_INC_STATS_BH(net, LINUX_MIB_LOCKDROPPEDICMPS);
356 
357         if (sk->sk_state == TCP_CLOSE)
358                 goto out;
359 
360         if (ipv6_hdr(skb)->hop_limit < inet6_sk(sk)->min_hopcount) {
361                 NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP);
362                 goto out;
363         }
364 
365         tp = tcp_sk(sk);
366         /* XXX (TFO) - tp->snd_una should be ISN (tcp_create_openreq_child() */
367         fastopen = tp->fastopen_rsk;
368         snd_una = fastopen ? tcp_rsk(fastopen)->snt_isn : tp->snd_una;
369         if (sk->sk_state != TCP_LISTEN &&
370             !between(seq, snd_una, tp->snd_nxt)) {
371                 NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
372                 goto out;
373         }
374 
375         np = inet6_sk(sk);
376 
377         if (type == NDISC_REDIRECT) {
378                 struct dst_entry *dst = __sk_dst_check(sk, np->dst_cookie);
379 
380                 if (dst)
381                         dst->ops->redirect(dst, sk, skb);
382                 goto out;
383         }
384 
385         if (type == ICMPV6_PKT_TOOBIG) {
386                 /* We are not interested in TCP_LISTEN and open_requests
387                  * (SYN-ACKs send out by Linux are always <576bytes so
388                  * they should go through unfragmented).
389                  */
390                 if (sk->sk_state == TCP_LISTEN)
391                         goto out;
392 
393                 if (!ip6_sk_accept_pmtu(sk))
394                         goto out;
395 
396                 tp->mtu_info = ntohl(info);
397                 if (!sock_owned_by_user(sk))
398                         tcp_v6_mtu_reduced(sk);
399                 else if (!test_and_set_bit(TCP_MTU_REDUCED_DEFERRED,
400                                            &tp->tsq_flags))
401                         sock_hold(sk);
402                 goto out;
403         }
404 
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(const struct sock *sk, struct dst_entry *dst,
439                               struct flowi *fl,
440                               struct request_sock *req,
441                               struct tcp_fastopen_cookie *foc,
442                               bool attach_req)
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,
452                                                IPPROTO_TCP)) == NULL)
453                 goto done;
454 
455         skb = tcp_make_synack(sk, dst, req, foc, attach_req);
456 
457         if (skb) {
458                 __tcp_v6_send_check(skb, &ireq->ir_v6_loc_addr,
459                                     &ireq->ir_v6_rmt_addr);
460 
461                 fl6->daddr = ireq->ir_v6_rmt_addr;
462                 if (np->repflow && ireq->pktopts)
463                         fl6->flowlabel = ip6_flowlabel(ipv6_hdr(ireq->pktopts));
464 
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(const 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(const 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 #endif
629 
630 static bool tcp_v6_inbound_md5_hash(const struct sock *sk,
631                                     const struct sk_buff *skb)
632 {
633 #ifdef CONFIG_TCP_MD5SIG
634         const __u8 *hash_location = NULL;
635         struct tcp_md5sig_key *hash_expected;
636         const struct ipv6hdr *ip6h = ipv6_hdr(skb);
637         const struct tcphdr *th = tcp_hdr(skb);
638         int genhash;
639         u8 newhash[16];
640 
641         hash_expected = tcp_v6_md5_do_lookup(sk, &ip6h->saddr);
642         hash_location = tcp_parse_md5sig_option(th);
643 
644         /* We've parsed the options - do we have a hash? */
645         if (!hash_expected && !hash_location)
646                 return false;
647 
648         if (hash_expected && !hash_location) {
649                 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5NOTFOUND);
650                 return true;
651         }
652 
653         if (!hash_expected && hash_location) {
654                 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5UNEXPECTED);
655                 return true;
656         }
657 
658         /* check the signature */
659         genhash = tcp_v6_md5_hash_skb(newhash,
660                                       hash_expected,
661                                       NULL, skb);
662 
663         if (genhash || memcmp(hash_location, newhash, 16) != 0) {
664                 net_info_ratelimited("MD5 Hash %s for [%pI6c]:%u->[%pI6c]:%u\n",
665                                      genhash ? "failed" : "mismatch",
666                                      &ip6h->saddr, ntohs(th->source),
667                                      &ip6h->daddr, ntohs(th->dest));
668                 return true;
669         }
670 #endif
671         return false;
672 }
673 
674 static void tcp_v6_init_req(struct request_sock *req,
675                             const struct sock *sk_listener,
676                             struct sk_buff *skb)
677 {
678         struct inet_request_sock *ireq = inet_rsk(req);
679         const struct ipv6_pinfo *np = inet6_sk(sk_listener);
680 
681         ireq->ir_v6_rmt_addr = ipv6_hdr(skb)->saddr;
682         ireq->ir_v6_loc_addr = ipv6_hdr(skb)->daddr;
683 
684         /* So that link locals have meaning */
685         if (!sk_listener->sk_bound_dev_if &&
686             ipv6_addr_type(&ireq->ir_v6_rmt_addr) & IPV6_ADDR_LINKLOCAL)
687                 ireq->ir_iif = tcp_v6_iif(skb);
688 
689         if (!TCP_SKB_CB(skb)->tcp_tw_isn &&
690             (ipv6_opt_accepted(sk_listener, skb, &TCP_SKB_CB(skb)->header.h6) ||
691              np->rxopt.bits.rxinfo ||
692              np->rxopt.bits.rxoinfo || np->rxopt.bits.rxhlim ||
693              np->rxopt.bits.rxohlim || np->repflow)) {
694                 atomic_inc(&skb->users);
695                 ireq->pktopts = skb;
696         }
697 }
698 
699 static struct dst_entry *tcp_v6_route_req(const struct sock *sk,
700                                           struct flowi *fl,
701                                           const struct request_sock *req,
702                                           bool *strict)
703 {
704         if (strict)
705                 *strict = true;
706         return inet6_csk_route_req(sk, &fl->u.ip6, req, IPPROTO_TCP);
707 }
708 
709 struct request_sock_ops tcp6_request_sock_ops __read_mostly = {
710         .family         =       AF_INET6,
711         .obj_size       =       sizeof(struct tcp6_request_sock),
712         .rtx_syn_ack    =       tcp_rtx_synack,
713         .send_ack       =       tcp_v6_reqsk_send_ack,
714         .destructor     =       tcp_v6_reqsk_destructor,
715         .send_reset     =       tcp_v6_send_reset,
716         .syn_ack_timeout =      tcp_syn_ack_timeout,
717 };
718 
719 static const struct tcp_request_sock_ops tcp_request_sock_ipv6_ops = {
720         .mss_clamp      =       IPV6_MIN_MTU - sizeof(struct tcphdr) -
721                                 sizeof(struct ipv6hdr),
722 #ifdef CONFIG_TCP_MD5SIG
723         .req_md5_lookup =       tcp_v6_md5_lookup,
724         .calc_md5_hash  =       tcp_v6_md5_hash_skb,
725 #endif
726         .init_req       =       tcp_v6_init_req,
727 #ifdef CONFIG_SYN_COOKIES
728         .cookie_init_seq =      cookie_v6_init_sequence,
729 #endif
730         .route_req      =       tcp_v6_route_req,
731         .init_seq       =       tcp_v6_init_sequence,
732         .send_synack    =       tcp_v6_send_synack,
733 };
734 
735 static void tcp_v6_send_response(const struct sock *sk, struct sk_buff *skb, u32 seq,
736                                  u32 ack, u32 win, u32 tsval, u32 tsecr,
737                                  int oif, struct tcp_md5sig_key *key, int rst,
738                                  u8 tclass, u32 label)
739 {
740         const struct tcphdr *th = tcp_hdr(skb);
741         struct tcphdr *t1;
742         struct sk_buff *buff;
743         struct flowi6 fl6;
744         struct net *net = sk ? sock_net(sk) : dev_net(skb_dst(skb)->dev);
745         struct sock *ctl_sk = net->ipv6.tcp_sk;
746         unsigned int tot_len = sizeof(struct tcphdr);
747         struct dst_entry *dst;
748         __be32 *topt;
749 
750         if (tsecr)
751                 tot_len += TCPOLEN_TSTAMP_ALIGNED;
752 #ifdef CONFIG_TCP_MD5SIG
753         if (key)
754                 tot_len += TCPOLEN_MD5SIG_ALIGNED;
755 #endif
756 
757         buff = alloc_skb(MAX_HEADER + sizeof(struct ipv6hdr) + tot_len,
758                          GFP_ATOMIC);
759         if (!buff)
760                 return;
761 
762         skb_reserve(buff, MAX_HEADER + sizeof(struct ipv6hdr) + tot_len);
763 
764         t1 = (struct tcphdr *) skb_push(buff, tot_len);
765         skb_reset_transport_header(buff);
766 
767         /* Swap the send and the receive. */
768         memset(t1, 0, sizeof(*t1));
769         t1->dest = th->source;
770         t1->source = th->dest;
771         t1->doff = tot_len / 4;
772         t1->seq = htonl(seq);
773         t1->ack_seq = htonl(ack);
774         t1->ack = !rst || !th->ack;
775         t1->rst = rst;
776         t1->window = htons(win);
777 
778         topt = (__be32 *)(t1 + 1);
779 
780         if (tsecr) {
781                 *topt++ = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
782                                 (TCPOPT_TIMESTAMP << 8) | TCPOLEN_TIMESTAMP);
783                 *topt++ = htonl(tsval);
784                 *topt++ = htonl(tsecr);
785         }
786 
787 #ifdef CONFIG_TCP_MD5SIG
788         if (key) {
789                 *topt++ = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
790                                 (TCPOPT_MD5SIG << 8) | TCPOLEN_MD5SIG);
791                 tcp_v6_md5_hash_hdr((__u8 *)topt, key,
792                                     &ipv6_hdr(skb)->saddr,
793                                     &ipv6_hdr(skb)->daddr, t1);
794         }
795 #endif
796 
797         memset(&fl6, 0, sizeof(fl6));
798         fl6.daddr = ipv6_hdr(skb)->saddr;
799         fl6.saddr = ipv6_hdr(skb)->daddr;
800         fl6.flowlabel = label;
801 
802         buff->ip_summed = CHECKSUM_PARTIAL;
803         buff->csum = 0;
804 
805         __tcp_v6_send_check(buff, &fl6.saddr, &fl6.daddr);
806 
807         fl6.flowi6_proto = IPPROTO_TCP;
808         if (rt6_need_strict(&fl6.daddr) && !oif)
809                 fl6.flowi6_oif = tcp_v6_iif(skb);
810         else
811                 fl6.flowi6_oif = oif;
812         fl6.flowi6_mark = IP6_REPLY_MARK(net, skb->mark);
813         fl6.fl6_dport = t1->dest;
814         fl6.fl6_sport = t1->source;
815         security_skb_classify_flow(skb, flowi6_to_flowi(&fl6));
816 
817         /* Pass a socket to ip6_dst_lookup either it is for RST
818          * Underlying function will use this to retrieve the network
819          * namespace
820          */
821         dst = ip6_dst_lookup_flow(ctl_sk, &fl6, NULL);
822         if (!IS_ERR(dst)) {
823                 skb_dst_set(buff, dst);
824                 ip6_xmit(ctl_sk, buff, &fl6, NULL, tclass);
825                 TCP_INC_STATS_BH(net, TCP_MIB_OUTSEGS);
826                 if (rst)
827                         TCP_INC_STATS_BH(net, TCP_MIB_OUTRSTS);
828                 return;
829         }
830 
831         kfree_skb(buff);
832 }
833 
834 static void tcp_v6_send_reset(const struct sock *sk, struct sk_buff *skb)
835 {
836         const struct tcphdr *th = tcp_hdr(skb);
837         u32 seq = 0, ack_seq = 0;
838         struct tcp_md5sig_key *key = NULL;
839 #ifdef CONFIG_TCP_MD5SIG
840         const __u8 *hash_location = NULL;
841         struct ipv6hdr *ipv6h = ipv6_hdr(skb);
842         unsigned char newhash[16];
843         int genhash;
844         struct sock *sk1 = NULL;
845 #endif
846         int oif;
847 
848         if (th->rst)
849                 return;
850 
851         /* If sk not NULL, it means we did a successful lookup and incoming
852          * route had to be correct. prequeue might have dropped our dst.
853          */
854         if (!sk && !ipv6_unicast_destination(skb))
855                 return;
856 
857 #ifdef CONFIG_TCP_MD5SIG
858         hash_location = tcp_parse_md5sig_option(th);
859         if (sk && sk_fullsock(sk)) {
860                 key = tcp_v6_md5_do_lookup(sk, &ipv6h->saddr);
861         } else if (hash_location) {
862                 /*
863                  * active side is lost. Try to find listening socket through
864                  * source port, and then find md5 key through listening socket.
865                  * we are not loose security here:
866                  * Incoming packet is checked with md5 hash with finding key,
867                  * no RST generated if md5 hash doesn't match.
868                  */
869                 sk1 = inet6_lookup_listener(dev_net(skb_dst(skb)->dev),
870                                            &tcp_hashinfo, &ipv6h->saddr,
871                                            th->source, &ipv6h->daddr,
872                                            ntohs(th->source), tcp_v6_iif(skb));
873                 if (!sk1)
874                         return;
875 
876                 rcu_read_lock();
877                 key = tcp_v6_md5_do_lookup(sk1, &ipv6h->saddr);
878                 if (!key)
879                         goto release_sk1;
880 
881                 genhash = tcp_v6_md5_hash_skb(newhash, key, NULL, skb);
882                 if (genhash || memcmp(hash_location, newhash, 16) != 0)
883                         goto release_sk1;
884         }
885 #endif
886 
887         if (th->ack)
888                 seq = ntohl(th->ack_seq);
889         else
890                 ack_seq = ntohl(th->seq) + th->syn + th->fin + skb->len -
891                           (th->doff << 2);
892 
893         oif = sk ? sk->sk_bound_dev_if : 0;
894         tcp_v6_send_response(sk, skb, seq, ack_seq, 0, 0, 0, oif, key, 1, 0, 0);
895 
896 #ifdef CONFIG_TCP_MD5SIG
897 release_sk1:
898         if (sk1) {
899                 rcu_read_unlock();
900                 sock_put(sk1);
901         }
902 #endif
903 }
904 
905 static void tcp_v6_send_ack(const struct sock *sk, struct sk_buff *skb, u32 seq,
906                             u32 ack, u32 win, u32 tsval, u32 tsecr, int oif,
907                             struct tcp_md5sig_key *key, u8 tclass,
908                             u32 label)
909 {
910         tcp_v6_send_response(sk, skb, seq, ack, win, tsval, tsecr, oif, key, 0,
911                              tclass, label);
912 }
913 
914 static void tcp_v6_timewait_ack(struct sock *sk, struct sk_buff *skb)
915 {
916         struct inet_timewait_sock *tw = inet_twsk(sk);
917         struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
918 
919         tcp_v6_send_ack(sk, skb, tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
920                         tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
921                         tcp_time_stamp + tcptw->tw_ts_offset,
922                         tcptw->tw_ts_recent, tw->tw_bound_dev_if, tcp_twsk_md5_key(tcptw),
923                         tw->tw_tclass, cpu_to_be32(tw->tw_flowlabel));
924 
925         inet_twsk_put(tw);
926 }
927 
928 static void tcp_v6_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb,
929                                   struct request_sock *req)
930 {
931         /* sk->sk_state == TCP_LISTEN -> for regular TCP_SYN_RECV
932          * sk->sk_state == TCP_SYN_RECV -> for Fast Open.
933          */
934         tcp_v6_send_ack(sk, skb, (sk->sk_state == TCP_LISTEN) ?
935                         tcp_rsk(req)->snt_isn + 1 : tcp_sk(sk)->snd_nxt,
936                         tcp_rsk(req)->rcv_nxt, req->rsk_rcv_wnd,
937                         tcp_time_stamp, req->ts_recent, sk->sk_bound_dev_if,
938                         tcp_v6_md5_do_lookup(sk, &ipv6_hdr(skb)->daddr),
939                         0, 0);
940 }
941 
942 
943 static struct sock *tcp_v6_cookie_check(struct sock *sk, struct sk_buff *skb)
944 {
945 #ifdef CONFIG_SYN_COOKIES
946         const struct tcphdr *th = tcp_hdr(skb);
947 
948         if (!th->syn)
949                 sk = cookie_v6_check(sk, skb);
950 #endif
951         return sk;
952 }
953 
954 static int tcp_v6_conn_request(struct sock *sk, struct sk_buff *skb)
955 {
956         if (skb->protocol == htons(ETH_P_IP))
957                 return tcp_v4_conn_request(sk, skb);
958 
959         if (!ipv6_unicast_destination(skb))
960                 goto drop;
961 
962         return tcp_conn_request(&tcp6_request_sock_ops,
963                                 &tcp_request_sock_ipv6_ops, sk, skb);
964 
965 drop:
966         NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
967         return 0; /* don't send reset */
968 }
969 
970 static struct sock *tcp_v6_syn_recv_sock(const struct sock *sk, struct sk_buff *skb,
971                                          struct request_sock *req,
972                                          struct dst_entry *dst,
973                                          struct request_sock *req_unhash,
974                                          bool *own_req)
975 {
976         struct inet_request_sock *ireq;
977         struct ipv6_pinfo *newnp;
978         const struct ipv6_pinfo *np = inet6_sk(sk);
979         struct ipv6_txoptions *opt;
980         struct tcp6_sock *newtcp6sk;
981         struct inet_sock *newinet;
982         struct tcp_sock *newtp;
983         struct sock *newsk;
984 #ifdef CONFIG_TCP_MD5SIG
985         struct tcp_md5sig_key *key;
986 #endif
987         struct flowi6 fl6;
988 
989         if (skb->protocol == htons(ETH_P_IP)) {
990                 /*
991                  *      v6 mapped
992                  */
993 
994                 newsk = tcp_v4_syn_recv_sock(sk, skb, req, dst,
995                                              req_unhash, own_req);
996 
997                 if (!newsk)
998                         return NULL;
999 
1000                 newtcp6sk = (struct tcp6_sock *)newsk;
1001                 inet_sk(newsk)->pinet6 = &newtcp6sk->inet6;
1002 
1003                 newinet = inet_sk(newsk);
1004                 newnp = inet6_sk(newsk);
1005                 newtp = tcp_sk(newsk);
1006 
1007                 memcpy(newnp, np, sizeof(struct ipv6_pinfo));
1008 
1009                 newnp->saddr = newsk->sk_v6_rcv_saddr;
1010 
1011                 inet_csk(newsk)->icsk_af_ops = &ipv6_mapped;
1012                 newsk->sk_backlog_rcv = tcp_v4_do_rcv;
1013 #ifdef CONFIG_TCP_MD5SIG
1014                 newtp->af_specific = &tcp_sock_ipv6_mapped_specific;
1015 #endif
1016 
1017                 newnp->ipv6_ac_list = NULL;
1018                 newnp->ipv6_fl_list = NULL;
1019                 newnp->pktoptions  = NULL;
1020                 newnp->opt         = NULL;
1021                 newnp->mcast_oif   = tcp_v6_iif(skb);
1022                 newnp->mcast_hops  = ipv6_hdr(skb)->hop_limit;
1023                 newnp->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(skb));
1024                 if (np->repflow)
1025                         newnp->flow_label = ip6_flowlabel(ipv6_hdr(skb));
1026 
1027                 /*
1028                  * No need to charge this sock to the relevant IPv6 refcnt debug socks count
1029                  * here, tcp_create_openreq_child now does this for us, see the comment in
1030                  * that function for the gory details. -acme
1031                  */
1032 
1033                 /* It is tricky place. Until this moment IPv4 tcp
1034                    worked with IPv6 icsk.icsk_af_ops.
1035                    Sync it now.
1036                  */
1037                 tcp_sync_mss(newsk, inet_csk(newsk)->icsk_pmtu_cookie);
1038 
1039                 return newsk;
1040         }
1041 
1042         ireq = inet_rsk(req);
1043 
1044         if (sk_acceptq_is_full(sk))
1045                 goto out_overflow;
1046 
1047         if (!dst) {
1048                 dst = inet6_csk_route_req(sk, &fl6, req, IPPROTO_TCP);
1049                 if (!dst)
1050                         goto out;
1051         }
1052 
1053         newsk = tcp_create_openreq_child(sk, req, skb);
1054         if (!newsk)
1055                 goto out_nonewsk;
1056 
1057         /*
1058          * No need to charge this sock to the relevant IPv6 refcnt debug socks
1059          * count here, tcp_create_openreq_child now does this for us, see the
1060          * comment in that function for the gory details. -acme
1061          */
1062 
1063         newsk->sk_gso_type = SKB_GSO_TCPV6;
1064         ip6_dst_store(newsk, dst, NULL, NULL);
1065         inet6_sk_rx_dst_set(newsk, skb);
1066 
1067         newtcp6sk = (struct tcp6_sock *)newsk;
1068         inet_sk(newsk)->pinet6 = &newtcp6sk->inet6;
1069 
1070         newtp = tcp_sk(newsk);
1071         newinet = inet_sk(newsk);
1072         newnp = inet6_sk(newsk);
1073 
1074         memcpy(newnp, np, sizeof(struct ipv6_pinfo));
1075 
1076         newsk->sk_v6_daddr = ireq->ir_v6_rmt_addr;
1077         newnp->saddr = ireq->ir_v6_loc_addr;
1078         newsk->sk_v6_rcv_saddr = ireq->ir_v6_loc_addr;
1079         newsk->sk_bound_dev_if = ireq->ir_iif;
1080 
1081         /* Now IPv6 options...
1082 
1083            First: no IPv4 options.
1084          */
1085         newinet->inet_opt = NULL;
1086         newnp->ipv6_ac_list = NULL;
1087         newnp->ipv6_fl_list = NULL;
1088 
1089         /* Clone RX bits */
1090         newnp->rxopt.all = np->rxopt.all;
1091 
1092         newnp->pktoptions = NULL;
1093         newnp->opt        = NULL;
1094         newnp->mcast_oif  = tcp_v6_iif(skb);
1095         newnp->mcast_hops = ipv6_hdr(skb)->hop_limit;
1096         newnp->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(skb));
1097         if (np->repflow)
1098                 newnp->flow_label = ip6_flowlabel(ipv6_hdr(skb));
1099 
1100         /* Clone native IPv6 options from listening socket (if any)
1101 
1102            Yes, keeping reference count would be much more clever,
1103            but we make one more one thing there: reattach optmem
1104            to newsk.
1105          */
1106         opt = rcu_dereference(np->opt);
1107         if (opt) {
1108                 opt = ipv6_dup_options(newsk, opt);
1109                 RCU_INIT_POINTER(newnp->opt, opt);
1110         }
1111         inet_csk(newsk)->icsk_ext_hdr_len = 0;
1112         if (opt)
1113                 inet_csk(newsk)->icsk_ext_hdr_len = opt->opt_nflen +
1114                                                     opt->opt_flen;
1115 
1116         tcp_ca_openreq_child(newsk, dst);
1117 
1118         tcp_sync_mss(newsk, dst_mtu(dst));
1119         newtp->advmss = dst_metric_advmss(dst);
1120         if (tcp_sk(sk)->rx_opt.user_mss &&
1121             tcp_sk(sk)->rx_opt.user_mss < newtp->advmss)
1122                 newtp->advmss = tcp_sk(sk)->rx_opt.user_mss;
1123 
1124         tcp_initialize_rcv_mss(newsk);
1125 
1126         newinet->inet_daddr = newinet->inet_saddr = LOOPBACK4_IPV6;
1127         newinet->inet_rcv_saddr = LOOPBACK4_IPV6;
1128 
1129 #ifdef CONFIG_TCP_MD5SIG
1130         /* Copy over the MD5 key from the original socket */
1131         key = tcp_v6_md5_do_lookup(sk, &newsk->sk_v6_daddr);
1132         if (key) {
1133                 /* We're using one, so create a matching key
1134                  * on the newsk structure. If we fail to get
1135                  * memory, then we end up not copying the key
1136                  * across. Shucks.
1137                  */
1138                 tcp_md5_do_add(newsk, (union tcp_md5_addr *)&newsk->sk_v6_daddr,
1139                                AF_INET6, key->key, key->keylen,
1140                                sk_gfp_mask(sk, GFP_ATOMIC));
1141         }
1142 #endif
1143 
1144         if (__inet_inherit_port(sk, newsk) < 0) {
1145                 inet_csk_prepare_forced_close(newsk);
1146                 tcp_done(newsk);
1147                 goto out;
1148         }
1149         *own_req = inet_ehash_nolisten(newsk, req_to_sk(req_unhash));
1150         if (*own_req) {
1151                 tcp_move_syn(newtp, req);
1152 
1153                 /* Clone pktoptions received with SYN, if we own the req */
1154                 if (ireq->pktopts) {
1155                         newnp->pktoptions = skb_clone(ireq->pktopts,
1156                                                       sk_gfp_mask(sk, GFP_ATOMIC));
1157                         consume_skb(ireq->pktopts);
1158                         ireq->pktopts = NULL;
1159                         if (newnp->pktoptions)
1160                                 skb_set_owner_r(newnp->pktoptions, newsk);
1161                 }
1162         }
1163 
1164         return newsk;
1165 
1166 out_overflow:
1167         NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
1168 out_nonewsk:
1169         dst_release(dst);
1170 out:
1171         NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
1172         return NULL;
1173 }
1174 
1175 /* The socket must have it's spinlock held when we get
1176  * here, unless it is a TCP_LISTEN socket.
1177  *
1178  * We have a potential double-lock case here, so even when
1179  * doing backlog processing we use the BH locking scheme.
1180  * This is because we cannot sleep with the original spinlock
1181  * held.
1182  */
1183 static int tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb)
1184 {
1185         struct ipv6_pinfo *np = inet6_sk(sk);
1186         struct tcp_sock *tp;
1187         struct sk_buff *opt_skb = NULL;
1188 
1189         /* Imagine: socket is IPv6. IPv4 packet arrives,
1190            goes to IPv4 receive handler and backlogged.
1191            From backlog it always goes here. Kerboom...
1192            Fortunately, tcp_rcv_established and rcv_established
1193            handle them correctly, but it is not case with
1194            tcp_v6_hnd_req and tcp_v6_send_reset().   --ANK
1195          */
1196 
1197         if (skb->protocol == htons(ETH_P_IP))
1198                 return tcp_v4_do_rcv(sk, skb);
1199 
1200         if (sk_filter(sk, skb))
1201                 goto discard;
1202 
1203         /*
1204          *      socket locking is here for SMP purposes as backlog rcv
1205          *      is currently called with bh processing disabled.
1206          */
1207 
1208         /* Do Stevens' IPV6_PKTOPTIONS.
1209 
1210            Yes, guys, it is the only place in our code, where we
1211            may make it not affecting IPv4.
1212            The rest of code is protocol independent,
1213            and I do not like idea to uglify IPv4.
1214 
1215            Actually, all the idea behind IPV6_PKTOPTIONS
1216            looks not very well thought. For now we latch
1217            options, received in the last packet, enqueued
1218            by tcp. Feel free to propose better solution.
1219                                                --ANK (980728)
1220          */
1221         if (np->rxopt.all)
1222                 opt_skb = skb_clone(skb, sk_gfp_mask(sk, GFP_ATOMIC));
1223 
1224         if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
1225                 struct dst_entry *dst = sk->sk_rx_dst;
1226 
1227                 sock_rps_save_rxhash(sk, skb);
1228                 sk_mark_napi_id(sk, skb);
1229                 if (dst) {
1230                         if (inet_sk(sk)->rx_dst_ifindex != skb->skb_iif ||
1231                             dst->ops->check(dst, np->rx_dst_cookie) == NULL) {
1232                                 dst_release(dst);
1233                                 sk->sk_rx_dst = NULL;
1234                         }
1235                 }
1236 
1237                 tcp_rcv_established(sk, skb, tcp_hdr(skb), skb->len);
1238                 if (opt_skb)
1239                         goto ipv6_pktoptions;
1240                 return 0;
1241         }
1242 
1243         if (tcp_checksum_complete(skb))
1244                 goto csum_err;
1245 
1246         if (sk->sk_state == TCP_LISTEN) {
1247                 struct sock *nsk = tcp_v6_cookie_check(sk, skb);
1248 
1249                 if (!nsk)
1250                         goto discard;
1251 
1252                 if (nsk != sk) {
1253                         sock_rps_save_rxhash(nsk, skb);
1254                         sk_mark_napi_id(nsk, skb);
1255                         if (tcp_child_process(sk, nsk, skb))
1256                                 goto reset;
1257                         if (opt_skb)
1258                                 __kfree_skb(opt_skb);
1259                         return 0;
1260                 }
1261         } else
1262                 sock_rps_save_rxhash(sk, skb);
1263 
1264         if (tcp_rcv_state_process(sk, skb))
1265                 goto reset;
1266         if (opt_skb)
1267                 goto ipv6_pktoptions;
1268         return 0;
1269 
1270 reset:
1271         tcp_v6_send_reset(sk, skb);
1272 discard:
1273         if (opt_skb)
1274                 __kfree_skb(opt_skb);
1275         kfree_skb(skb);
1276         return 0;
1277 csum_err:
1278         TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_CSUMERRORS);
1279         TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_INERRS);
1280         goto discard;
1281 
1282 
1283 ipv6_pktoptions:
1284         /* Do you ask, what is it?
1285 
1286            1. skb was enqueued by tcp.
1287            2. skb is added to tail of read queue, rather than out of order.
1288            3. socket is not in passive state.
1289            4. Finally, it really contains options, which user wants to receive.
1290          */
1291         tp = tcp_sk(sk);
1292         if (TCP_SKB_CB(opt_skb)->end_seq == tp->rcv_nxt &&
1293             !((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN))) {
1294                 if (np->rxopt.bits.rxinfo || np->rxopt.bits.rxoinfo)
1295                         np->mcast_oif = tcp_v6_iif(opt_skb);
1296                 if (np->rxopt.bits.rxhlim || np->rxopt.bits.rxohlim)
1297                         np->mcast_hops = ipv6_hdr(opt_skb)->hop_limit;
1298                 if (np->rxopt.bits.rxflow || np->rxopt.bits.rxtclass)
1299                         np->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(opt_skb));
1300                 if (np->repflow)
1301                         np->flow_label = ip6_flowlabel(ipv6_hdr(opt_skb));
1302                 if (ipv6_opt_accepted(sk, opt_skb, &TCP_SKB_CB(opt_skb)->header.h6)) {
1303                         skb_set_owner_r(opt_skb, sk);
1304                         opt_skb = xchg(&np->pktoptions, opt_skb);
1305                 } else {
1306                         __kfree_skb(opt_skb);
1307                         opt_skb = xchg(&np->pktoptions, NULL);
1308                 }
1309         }
1310 
1311         kfree_skb(opt_skb);
1312         return 0;
1313 }
1314 
1315 static void tcp_v6_fill_cb(struct sk_buff *skb, const struct ipv6hdr *hdr,
1316                            const struct tcphdr *th)
1317 {
1318         /* This is tricky: we move IP6CB at its correct location into
1319          * TCP_SKB_CB(). It must be done after xfrm6_policy_check(), because
1320          * _decode_session6() uses IP6CB().
1321          * barrier() makes sure compiler won't play aliasing games.
1322          */
1323         memmove(&TCP_SKB_CB(skb)->header.h6, IP6CB(skb),
1324                 sizeof(struct inet6_skb_parm));
1325         barrier();
1326 
1327         TCP_SKB_CB(skb)->seq = ntohl(th->seq);
1328         TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
1329                                     skb->len - th->doff*4);
1330         TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
1331         TCP_SKB_CB(skb)->tcp_flags = tcp_flag_byte(th);
1332         TCP_SKB_CB(skb)->tcp_tw_isn = 0;
1333         TCP_SKB_CB(skb)->ip_dsfield = ipv6_get_dsfield(hdr);
1334         TCP_SKB_CB(skb)->sacked = 0;
1335 }
1336 
1337 static void tcp_v6_restore_cb(struct sk_buff *skb)
1338 {
1339         /* We need to move header back to the beginning if xfrm6_policy_check()
1340          * and tcp_v6_fill_cb() are going to be called again.
1341          */
1342         memmove(IP6CB(skb), &TCP_SKB_CB(skb)->header.h6,
1343                 sizeof(struct inet6_skb_parm));
1344 }
1345 
1346 static int tcp_v6_rcv(struct sk_buff *skb)
1347 {
1348         const struct tcphdr *th;
1349         const struct ipv6hdr *hdr;
1350         struct sock *sk;
1351         int ret;
1352         struct net *net = dev_net(skb->dev);
1353 
1354         if (skb->pkt_type != PACKET_HOST)
1355                 goto discard_it;
1356 
1357         /*
1358          *      Count it even if it's bad.
1359          */
1360         TCP_INC_STATS_BH(net, TCP_MIB_INSEGS);
1361 
1362         if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
1363                 goto discard_it;
1364 
1365         th = tcp_hdr(skb);
1366 
1367         if (th->doff < sizeof(struct tcphdr)/4)
1368                 goto bad_packet;
1369         if (!pskb_may_pull(skb, th->doff*4))
1370                 goto discard_it;
1371 
1372         if (skb_checksum_init(skb, IPPROTO_TCP, ip6_compute_pseudo))
1373                 goto csum_error;
1374 
1375         th = tcp_hdr(skb);
1376         hdr = ipv6_hdr(skb);
1377 
1378 lookup:
1379         sk = __inet6_lookup_skb(&tcp_hashinfo, skb, th->source, th->dest,
1380                                 inet6_iif(skb));
1381         if (!sk)
1382                 goto no_tcp_socket;
1383 
1384 process:
1385         if (sk->sk_state == TCP_TIME_WAIT)
1386                 goto do_time_wait;
1387 
1388         if (sk->sk_state == TCP_NEW_SYN_RECV) {
1389                 struct request_sock *req = inet_reqsk(sk);
1390                 struct sock *nsk;
1391 
1392                 sk = req->rsk_listener;
1393                 tcp_v6_fill_cb(skb, hdr, th);
1394                 if (tcp_v6_inbound_md5_hash(sk, skb)) {
1395                         reqsk_put(req);
1396                         goto discard_it;
1397                 }
1398                 if (unlikely(sk->sk_state != TCP_LISTEN)) {
1399                         inet_csk_reqsk_queue_drop_and_put(sk, req);
1400                         goto lookup;
1401                 }
1402                 sock_hold(sk);
1403                 nsk = tcp_check_req(sk, skb, req, false);
1404                 if (!nsk) {
1405                         reqsk_put(req);
1406                         goto discard_and_relse;
1407                 }
1408                 if (nsk == sk) {
1409                         reqsk_put(req);
1410                         tcp_v6_restore_cb(skb);
1411                 } else if (tcp_child_process(sk, nsk, skb)) {
1412                         tcp_v6_send_reset(nsk, skb);
1413                         goto discard_and_relse;
1414                 } else {
1415                         sock_put(sk);
1416                         return 0;
1417                 }
1418         }
1419         if (hdr->hop_limit < inet6_sk(sk)->min_hopcount) {
1420                 NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP);
1421                 goto discard_and_relse;
1422         }
1423 
1424         if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb))
1425                 goto discard_and_relse;
1426 
1427         tcp_v6_fill_cb(skb, hdr, th);
1428 
1429         if (tcp_v6_inbound_md5_hash(sk, skb))
1430                 goto discard_and_relse;
1431 
1432         if (sk_filter(sk, skb))
1433                 goto discard_and_relse;
1434 
1435         skb->dev = NULL;
1436 
1437         if (sk->sk_state == TCP_LISTEN) {
1438                 ret = tcp_v6_do_rcv(sk, skb);
1439                 goto put_and_return;
1440         }
1441 
1442         sk_incoming_cpu_update(sk);
1443 
1444         bh_lock_sock_nested(sk);
1445         tcp_sk(sk)->segs_in += max_t(u16, 1, skb_shinfo(skb)->gso_segs);
1446         ret = 0;
1447         if (!sock_owned_by_user(sk)) {
1448                 if (!tcp_prequeue(sk, skb))
1449                         ret = tcp_v6_do_rcv(sk, skb);
1450         } else if (unlikely(sk_add_backlog(sk, skb,
1451                                            sk->sk_rcvbuf + sk->sk_sndbuf))) {
1452                 bh_unlock_sock(sk);
1453                 NET_INC_STATS_BH(net, LINUX_MIB_TCPBACKLOGDROP);
1454                 goto discard_and_relse;
1455         }
1456         bh_unlock_sock(sk);
1457 
1458 put_and_return:
1459         sock_put(sk);
1460         return ret ? -1 : 0;
1461 
1462 no_tcp_socket:
1463         if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb))
1464                 goto discard_it;
1465 
1466         tcp_v6_fill_cb(skb, hdr, th);
1467 
1468         if (tcp_checksum_complete(skb)) {
1469 csum_error:
1470                 TCP_INC_STATS_BH(net, TCP_MIB_CSUMERRORS);
1471 bad_packet:
1472                 TCP_INC_STATS_BH(net, TCP_MIB_INERRS);
1473         } else {
1474                 tcp_v6_send_reset(NULL, skb);
1475         }
1476 
1477 discard_it:
1478         kfree_skb(skb);
1479         return 0;
1480 
1481 discard_and_relse:
1482         sock_put(sk);
1483         goto discard_it;
1484 
1485 do_time_wait:
1486         if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
1487                 inet_twsk_put(inet_twsk(sk));
1488                 goto discard_it;
1489         }
1490 
1491         tcp_v6_fill_cb(skb, hdr, th);
1492 
1493         if (tcp_checksum_complete(skb)) {
1494                 inet_twsk_put(inet_twsk(sk));
1495                 goto csum_error;
1496         }
1497 
1498         switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) {
1499         case TCP_TW_SYN:
1500         {
1501                 struct sock *sk2;
1502 
1503                 sk2 = inet6_lookup_listener(dev_net(skb->dev), &tcp_hashinfo,
1504                                             &ipv6_hdr(skb)->saddr, th->source,
1505                                             &ipv6_hdr(skb)->daddr,
1506                                             ntohs(th->dest), tcp_v6_iif(skb));
1507                 if (sk2) {
1508                         struct inet_timewait_sock *tw = inet_twsk(sk);
1509                         inet_twsk_deschedule_put(tw);
1510                         sk = sk2;
1511                         tcp_v6_restore_cb(skb);
1512                         goto process;
1513                 }
1514                 /* Fall through to ACK */
1515         }
1516         case TCP_TW_ACK:
1517                 tcp_v6_timewait_ack(sk, skb);
1518                 break;
1519         case TCP_TW_RST:
1520                 tcp_v6_restore_cb(skb);
1521                 tcp_v6_send_reset(sk, skb);
1522                 inet_twsk_deschedule_put(inet_twsk(sk));
1523                 goto discard_it;
1524         case TCP_TW_SUCCESS:
1525                 ;
1526         }
1527         goto discard_it;
1528 }
1529 
1530 static void tcp_v6_early_demux(struct sk_buff *skb)
1531 {
1532         const struct ipv6hdr *hdr;
1533         const struct tcphdr *th;
1534         struct sock *sk;
1535 
1536         if (skb->pkt_type != PACKET_HOST)
1537                 return;
1538 
1539         if (!pskb_may_pull(skb, skb_transport_offset(skb) + sizeof(struct tcphdr)))
1540                 return;
1541 
1542         hdr = ipv6_hdr(skb);
1543         th = tcp_hdr(skb);
1544 
1545         if (th->doff < sizeof(struct tcphdr) / 4)
1546                 return;
1547 
1548         /* Note : We use inet6_iif() here, not tcp_v6_iif() */
1549         sk = __inet6_lookup_established(dev_net(skb->dev), &tcp_hashinfo,
1550                                         &hdr->saddr, th->source,
1551                                         &hdr->daddr, ntohs(th->dest),
1552                                         inet6_iif(skb));
1553         if (sk) {
1554                 skb->sk = sk;
1555                 skb->destructor = sock_edemux;
1556                 if (sk_fullsock(sk)) {
1557                         struct dst_entry *dst = READ_ONCE(sk->sk_rx_dst);
1558 
1559                         if (dst)
1560                                 dst = dst_check(dst, inet6_sk(sk)->rx_dst_cookie);
1561                         if (dst &&
1562                             inet_sk(sk)->rx_dst_ifindex == skb->skb_iif)
1563                                 skb_dst_set_noref(skb, dst);
1564                 }
1565         }
1566 }
1567 
1568 static struct timewait_sock_ops tcp6_timewait_sock_ops = {
1569         .twsk_obj_size  = sizeof(struct tcp6_timewait_sock),
1570         .twsk_unique    = tcp_twsk_unique,
1571         .twsk_destructor = tcp_twsk_destructor,
1572 };
1573 
1574 static const struct inet_connection_sock_af_ops ipv6_specific = {
1575         .queue_xmit        = inet6_csk_xmit,
1576         .send_check        = tcp_v6_send_check,
1577         .rebuild_header    = inet6_sk_rebuild_header,
1578         .sk_rx_dst_set     = inet6_sk_rx_dst_set,
1579         .conn_request      = tcp_v6_conn_request,
1580         .syn_recv_sock     = tcp_v6_syn_recv_sock,
1581         .net_header_len    = sizeof(struct ipv6hdr),
1582         .net_frag_header_len = sizeof(struct frag_hdr),
1583         .setsockopt        = ipv6_setsockopt,
1584         .getsockopt        = ipv6_getsockopt,
1585         .addr2sockaddr     = inet6_csk_addr2sockaddr,
1586         .sockaddr_len      = sizeof(struct sockaddr_in6),
1587         .bind_conflict     = inet6_csk_bind_conflict,
1588 #ifdef CONFIG_COMPAT
1589         .compat_setsockopt = compat_ipv6_setsockopt,
1590         .compat_getsockopt = compat_ipv6_getsockopt,
1591 #endif
1592         .mtu_reduced       = tcp_v6_mtu_reduced,
1593 };
1594 
1595 #ifdef CONFIG_TCP_MD5SIG
1596 static const struct tcp_sock_af_ops tcp_sock_ipv6_specific = {
1597         .md5_lookup     =       tcp_v6_md5_lookup,
1598         .calc_md5_hash  =       tcp_v6_md5_hash_skb,
1599         .md5_parse      =       tcp_v6_parse_md5_keys,
1600 };
1601 #endif
1602 
1603 /*
1604  *      TCP over IPv4 via INET6 API
1605  */
1606 static const struct inet_connection_sock_af_ops ipv6_mapped = {
1607         .queue_xmit        = ip_queue_xmit,
1608         .send_check        = tcp_v4_send_check,
1609         .rebuild_header    = inet_sk_rebuild_header,
1610         .sk_rx_dst_set     = inet_sk_rx_dst_set,
1611         .conn_request      = tcp_v6_conn_request,
1612         .syn_recv_sock     = tcp_v6_syn_recv_sock,
1613         .net_header_len    = sizeof(struct iphdr),
1614         .setsockopt        = ipv6_setsockopt,
1615         .getsockopt        = ipv6_getsockopt,
1616         .addr2sockaddr     = inet6_csk_addr2sockaddr,
1617         .sockaddr_len      = sizeof(struct sockaddr_in6),
1618         .bind_conflict     = inet6_csk_bind_conflict,
1619 #ifdef CONFIG_COMPAT
1620         .compat_setsockopt = compat_ipv6_setsockopt,
1621         .compat_getsockopt = compat_ipv6_getsockopt,
1622 #endif
1623         .mtu_reduced       = tcp_v4_mtu_reduced,
1624 };
1625 
1626 #ifdef CONFIG_TCP_MD5SIG
1627 static const struct tcp_sock_af_ops tcp_sock_ipv6_mapped_specific = {
1628         .md5_lookup     =       tcp_v4_md5_lookup,
1629         .calc_md5_hash  =       tcp_v4_md5_hash_skb,
1630         .md5_parse      =       tcp_v6_parse_md5_keys,
1631 };
1632 #endif
1633 
1634 /* NOTE: A lot of things set to zero explicitly by call to
1635  *       sk_alloc() so need not be done here.
1636  */
1637 static int tcp_v6_init_sock(struct sock *sk)
1638 {
1639         struct inet_connection_sock *icsk = inet_csk(sk);
1640 
1641         tcp_init_sock(sk);
1642 
1643         icsk->icsk_af_ops = &ipv6_specific;
1644 
1645 #ifdef CONFIG_TCP_MD5SIG
1646         tcp_sk(sk)->af_specific = &tcp_sock_ipv6_specific;
1647 #endif
1648 
1649         return 0;
1650 }
1651 
1652 static void tcp_v6_destroy_sock(struct sock *sk)
1653 {
1654         tcp_v4_destroy_sock(sk);
1655         inet6_destroy_sock(sk);
1656 }
1657 
1658 #ifdef CONFIG_PROC_FS
1659 /* Proc filesystem TCPv6 sock list dumping. */
1660 static void get_openreq6(struct seq_file *seq,
1661                          const struct request_sock *req, int i)
1662 {
1663         long ttd = req->rsk_timer.expires - jiffies;
1664         const struct in6_addr *src = &inet_rsk(req)->ir_v6_loc_addr;
1665         const struct in6_addr *dest = &inet_rsk(req)->ir_v6_rmt_addr;
1666 
1667         if (ttd < 0)
1668                 ttd = 0;
1669 
1670         seq_printf(seq,
1671                    "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
1672                    "%02X %08X:%08X %02X:%08lX %08X %5u %8d %d %d %pK\n",
1673                    i,
1674                    src->s6_addr32[0], src->s6_addr32[1],
1675                    src->s6_addr32[2], src->s6_addr32[3],
1676                    inet_rsk(req)->ir_num,
1677                    dest->s6_addr32[0], dest->s6_addr32[1],
1678                    dest->s6_addr32[2], dest->s6_addr32[3],
1679                    ntohs(inet_rsk(req)->ir_rmt_port),
1680                    TCP_SYN_RECV,
1681                    0, 0, /* could print option size, but that is af dependent. */
1682                    1,   /* timers active (only the expire timer) */
1683                    jiffies_to_clock_t(ttd),
1684                    req->num_timeout,
1685                    from_kuid_munged(seq_user_ns(seq),
1686                                     sock_i_uid(req->rsk_listener)),
1687                    0,  /* non standard timer */
1688                    0, /* open_requests have no inode */
1689                    0, req);
1690 }
1691 
1692 static void get_tcp6_sock(struct seq_file *seq, struct sock *sp, int i)
1693 {
1694         const struct in6_addr *dest, *src;
1695         __u16 destp, srcp;
1696         int timer_active;
1697         unsigned long timer_expires;
1698         const struct inet_sock *inet = inet_sk(sp);
1699         const struct tcp_sock *tp = tcp_sk(sp);
1700         const struct inet_connection_sock *icsk = inet_csk(sp);
1701         const struct fastopen_queue *fastopenq = &icsk->icsk_accept_queue.fastopenq;
1702         int rx_queue;
1703         int state;
1704 
1705         dest  = &sp->sk_v6_daddr;
1706         src   = &sp->sk_v6_rcv_saddr;
1707         destp = ntohs(inet->inet_dport);
1708         srcp  = ntohs(inet->inet_sport);
1709 
1710         if (icsk->icsk_pending == ICSK_TIME_RETRANS) {
1711                 timer_active    = 1;
1712                 timer_expires   = icsk->icsk_timeout;
1713         } else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
1714                 timer_active    = 4;
1715                 timer_expires   = icsk->icsk_timeout;
1716         } else if (timer_pending(&sp->sk_timer)) {
1717                 timer_active    = 2;
1718                 timer_expires   = sp->sk_timer.expires;
1719         } else {
1720                 timer_active    = 0;
1721                 timer_expires = jiffies;
1722         }
1723 
1724         state = sk_state_load(sp);
1725         if (state == TCP_LISTEN)
1726                 rx_queue = sp->sk_ack_backlog;
1727         else
1728                 /* Because we don't lock the socket,
1729                  * we might find a transient negative value.
1730                  */
1731                 rx_queue = max_t(int, tp->rcv_nxt - tp->copied_seq, 0);
1732 
1733         seq_printf(seq,
1734                    "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
1735                    "%02X %08X:%08X %02X:%08lX %08X %5u %8d %lu %d %pK %lu %lu %u %u %d\n",
1736                    i,
1737                    src->s6_addr32[0], src->s6_addr32[1],
1738                    src->s6_addr32[2], src->s6_addr32[3], srcp,
1739                    dest->s6_addr32[0], dest->s6_addr32[1],
1740                    dest->s6_addr32[2], dest->s6_addr32[3], destp,
1741                    state,
1742                    tp->write_seq - tp->snd_una,
1743                    rx_queue,
1744                    timer_active,
1745                    jiffies_delta_to_clock_t(timer_expires - jiffies),
1746                    icsk->icsk_retransmits,
1747                    from_kuid_munged(seq_user_ns(seq), sock_i_uid(sp)),
1748                    icsk->icsk_probes_out,
1749                    sock_i_ino(sp),
1750                    atomic_read(&sp->sk_refcnt), sp,
1751                    jiffies_to_clock_t(icsk->icsk_rto),
1752                    jiffies_to_clock_t(icsk->icsk_ack.ato),
1753                    (icsk->icsk_ack.quick << 1) | icsk->icsk_ack.pingpong,
1754                    tp->snd_cwnd,
1755                    state == TCP_LISTEN ?
1756                         fastopenq->max_qlen :
1757                         (tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh)
1758                    );
1759 }
1760 
1761 static void get_timewait6_sock(struct seq_file *seq,
1762                                struct inet_timewait_sock *tw, int i)
1763 {
1764         long delta = tw->tw_timer.expires - jiffies;
1765         const struct in6_addr *dest, *src;
1766         __u16 destp, srcp;
1767 
1768         dest = &tw->tw_v6_daddr;
1769         src  = &tw->tw_v6_rcv_saddr;
1770         destp = ntohs(tw->tw_dport);
1771         srcp  = ntohs(tw->tw_sport);
1772 
1773         seq_printf(seq,
1774                    "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
1775                    "%02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK\n",
1776                    i,
1777                    src->s6_addr32[0], src->s6_addr32[1],
1778                    src->s6_addr32[2], src->s6_addr32[3], srcp,
1779                    dest->s6_addr32[0], dest->s6_addr32[1],
1780                    dest->s6_addr32[2], dest->s6_addr32[3], destp,
1781                    tw->tw_substate, 0, 0,
1782                    3, jiffies_delta_to_clock_t(delta), 0, 0, 0, 0,
1783                    atomic_read(&tw->tw_refcnt), tw);
1784 }
1785 
1786 static int tcp6_seq_show(struct seq_file *seq, void *v)
1787 {
1788         struct tcp_iter_state *st;
1789         struct sock *sk = v;
1790 
1791         if (v == SEQ_START_TOKEN) {
1792                 seq_puts(seq,
1793                          "  sl  "
1794                          "local_address                         "
1795                          "remote_address                        "
1796                          "st tx_queue rx_queue tr tm->when retrnsmt"
1797                          "   uid  timeout inode\n");
1798                 goto out;
1799         }
1800         st = seq->private;
1801 
1802         if (sk->sk_state == TCP_TIME_WAIT)
1803                 get_timewait6_sock(seq, v, st->num);
1804         else if (sk->sk_state == TCP_NEW_SYN_RECV)
1805                 get_openreq6(seq, v, st->num);
1806         else
1807                 get_tcp6_sock(seq, v, st->num);
1808 out:
1809         return 0;
1810 }
1811 
1812 static const struct file_operations tcp6_afinfo_seq_fops = {
1813         .owner   = THIS_MODULE,
1814         .open    = tcp_seq_open,
1815         .read    = seq_read,
1816         .llseek  = seq_lseek,
1817         .release = seq_release_net
1818 };
1819 
1820 static struct tcp_seq_afinfo tcp6_seq_afinfo = {
1821         .name           = "tcp6",
1822         .family         = AF_INET6,
1823         .seq_fops       = &tcp6_afinfo_seq_fops,
1824         .seq_ops        = {
1825                 .show           = tcp6_seq_show,
1826         },
1827 };
1828 
1829 int __net_init tcp6_proc_init(struct net *net)
1830 {
1831         return tcp_proc_register(net, &tcp6_seq_afinfo);
1832 }
1833 
1834 void tcp6_proc_exit(struct net *net)
1835 {
1836         tcp_proc_unregister(net, &tcp6_seq_afinfo);
1837 }
1838 #endif
1839 
1840 static void tcp_v6_clear_sk(struct sock *sk, int size)
1841 {
1842         struct inet_sock *inet = inet_sk(sk);
1843 
1844         /* we do not want to clear pinet6 field, because of RCU lookups */
1845         sk_prot_clear_nulls(sk, offsetof(struct inet_sock, pinet6));
1846 
1847         size -= offsetof(struct inet_sock, pinet6) + sizeof(inet->pinet6);
1848         memset(&inet->pinet6 + 1, 0, size);
1849 }
1850 
1851 struct proto tcpv6_prot = {
1852         .name                   = "TCPv6",
1853         .owner                  = THIS_MODULE,
1854         .close                  = tcp_close,
1855         .connect                = tcp_v6_connect,
1856         .disconnect             = tcp_disconnect,
1857         .accept                 = inet_csk_accept,
1858         .ioctl                  = tcp_ioctl,
1859         .init                   = tcp_v6_init_sock,
1860         .destroy                = tcp_v6_destroy_sock,
1861         .shutdown               = tcp_shutdown,
1862         .setsockopt             = tcp_setsockopt,
1863         .getsockopt             = tcp_getsockopt,
1864         .recvmsg                = tcp_recvmsg,
1865         .sendmsg                = tcp_sendmsg,
1866         .sendpage               = tcp_sendpage,
1867         .backlog_rcv            = tcp_v6_do_rcv,
1868         .release_cb             = tcp_release_cb,
1869         .hash                   = inet_hash,
1870         .unhash                 = inet_unhash,
1871         .get_port               = inet_csk_get_port,
1872         .enter_memory_pressure  = tcp_enter_memory_pressure,
1873         .stream_memory_free     = tcp_stream_memory_free,
1874         .sockets_allocated      = &tcp_sockets_allocated,
1875         .memory_allocated       = &tcp_memory_allocated,
1876         .memory_pressure        = &tcp_memory_pressure,
1877         .orphan_count           = &tcp_orphan_count,
1878         .sysctl_mem             = sysctl_tcp_mem,
1879         .sysctl_wmem            = sysctl_tcp_wmem,
1880         .sysctl_rmem            = sysctl_tcp_rmem,
1881         .max_header             = MAX_TCP_HEADER,
1882         .obj_size               = sizeof(struct tcp6_sock),
1883         .slab_flags             = SLAB_DESTROY_BY_RCU,
1884         .twsk_prot              = &tcp6_timewait_sock_ops,
1885         .rsk_prot               = &tcp6_request_sock_ops,
1886         .h.hashinfo             = &tcp_hashinfo,
1887         .no_autobind            = true,
1888 #ifdef CONFIG_COMPAT
1889         .compat_setsockopt      = compat_tcp_setsockopt,
1890         .compat_getsockopt      = compat_tcp_getsockopt,
1891 #endif
1892         .clear_sk               = tcp_v6_clear_sk,
1893         .diag_destroy           = tcp_abort,
1894 };
1895 
1896 static const struct inet6_protocol tcpv6_protocol = {
1897         .early_demux    =       tcp_v6_early_demux,
1898         .handler        =       tcp_v6_rcv,
1899         .err_handler    =       tcp_v6_err,
1900         .flags          =       INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
1901 };
1902 
1903 static struct inet_protosw tcpv6_protosw = {
1904         .type           =       SOCK_STREAM,
1905         .protocol       =       IPPROTO_TCP,
1906         .prot           =       &tcpv6_prot,
1907         .ops            =       &inet6_stream_ops,
1908         .flags          =       INET_PROTOSW_PERMANENT |
1909                                 INET_PROTOSW_ICSK,
1910 };
1911 
1912 static int __net_init tcpv6_net_init(struct net *net)
1913 {
1914         return inet_ctl_sock_create(&net->ipv6.tcp_sk, PF_INET6,
1915                                     SOCK_RAW, IPPROTO_TCP, net);
1916 }
1917 
1918 static void __net_exit tcpv6_net_exit(struct net *net)
1919 {
1920         inet_ctl_sock_destroy(net->ipv6.tcp_sk);
1921 }
1922 
1923 static void __net_exit tcpv6_net_exit_batch(struct list_head *net_exit_list)
1924 {
1925         inet_twsk_purge(&tcp_hashinfo, &tcp_death_row, AF_INET6);
1926 }
1927 
1928 static struct pernet_operations tcpv6_net_ops = {
1929         .init       = tcpv6_net_init,
1930         .exit       = tcpv6_net_exit,
1931         .exit_batch = tcpv6_net_exit_batch,
1932 };
1933 
1934 int __init tcpv6_init(void)
1935 {
1936         int ret;
1937 
1938         ret = inet6_add_protocol(&tcpv6_protocol, IPPROTO_TCP);
1939         if (ret)
1940                 goto out;
1941 
1942         /* register inet6 protocol */
1943         ret = inet6_register_protosw(&tcpv6_protosw);
1944         if (ret)
1945                 goto out_tcpv6_protocol;
1946 
1947         ret = register_pernet_subsys(&tcpv6_net_ops);
1948         if (ret)
1949                 goto out_tcpv6_protosw;
1950 out:
1951         return ret;
1952 
1953 out_tcpv6_protosw:
1954         inet6_unregister_protosw(&tcpv6_protosw);
1955 out_tcpv6_protocol:
1956         inet6_del_protocol(&tcpv6_protocol, IPPROTO_TCP);
1957         goto out;
1958 }
1959 
1960 void tcpv6_exit(void)
1961 {
1962         unregister_pernet_subsys(&tcpv6_net_ops);
1963         inet6_unregister_protosw(&tcpv6_protosw);
1964         inet6_del_protocol(&tcpv6_protocol, IPPROTO_TCP);
1965 }
1966 

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