net/ipv6/tcp_ipv6.c

   1 /*
   2  *      TCP over IPv6
   3  *      Linux INET6 implementation
   4  *
   5  *      Authors:
   6  *      Pedro Roque             <roque@di.fc.ul.pt>
   7  *
   8  *      Based on:
   9  *      linux/net/ipv4/tcp.c
  10  *      linux/net/ipv4/tcp_input.c
  11  *      linux/net/ipv4/tcp_output.c
  12  *
  13  *      Fixes:
  14  *      Hideaki YOSHIFUJI       :       sin6_scope_id support
  15  *      YOSHIFUJI Hideaki @USAGI and:   Support IPV6_V6ONLY socket option, which
  16  *      Alexey Kuznetsov                allow both IPv4 and IPv6 sockets to bind
  17  *                                      a single port at the same time.
  18  *      YOSHIFUJI Hideaki @USAGI:       convert /proc/net/tcp6 to seq_file.
  19  *
  20  *      This program is free software; you can redistribute it and/or
  21  *      modify it under the terms of the GNU General Public License
  22  *      as published by the Free Software Foundation; either version
  23  *      2 of the License, or (at your option) any later version.
  24  */
  25
  26 #include <linux/bottom_half.h>
  27 #include <linux/module.h>
  28 #include <linux/errno.h>
  29 #include <linux/types.h>
  30 #include <linux/socket.h>
  31 #include <linux/sockios.h>
  32 #include <linux/net.h>
  33 #include <linux/jiffies.h>
  34 #include <linux/in.h>
  35 #include <linux/in6.h>
  36 #include <linux/netdevice.h>
  37 #include <linux/init.h>
  38 #include <linux/jhash.h>
  39 #include <linux/ipsec.h>
  40 #include <linux/times.h>
  41 #include <linux/slab.h>
  42 #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 <crypto/hash.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, lockdep_sock_is_held(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(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(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(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(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                               enum tcp_synack_type synack_type)
 443 {
 444         struct inet_request_sock *ireq = inet_rsk(req);
 445         struct ipv6_pinfo *np = inet6_sk(sk);
 446         struct ipv6_txoptions *opt;
 447         struct flowi6 *fl6 = &fl->u.ip6;
 448         struct sk_buff *skb;
 449         int err = -ENOMEM;
 450
 451         /* First, grab a route. */
 452         if (!dst && (dst = inet6_csk_route_req(sk, fl6, req,
 453                                                IPPROTO_TCP)) == NULL)
 454                 goto done;
 455
 456         skb = tcp_make_synack(sk, dst, req, foc, synack_type);
 457
 458         if (skb) {
 459                 __tcp_v6_send_check(skb, &ireq->ir_v6_loc_addr,
 460                                     &ireq->ir_v6_rmt_addr);
 461
 462                 fl6->daddr = ireq->ir_v6_rmt_addr;
 463                 if (np->repflow && ireq->pktopts)
 464                         fl6->flowlabel = ip6_flowlabel(ipv6_hdr(ireq->pktopts));
 465
 466                 rcu_read_lock();
 467                 opt = ireq->ipv6_opt;
 468                 if (!opt)
 469                         opt = rcu_dereference(np->opt);
 470                 err = ip6_xmit(sk, skb, fl6, opt, np->tclass);
 471                 rcu_read_unlock();
 472                 err = net_xmit_eval(err);
 473         }
 474
 475 done:
 476         return err;
 477 }
 478
 479
 480 static void tcp_v6_reqsk_destructor(struct request_sock *req)
 481 {
 482         kfree(inet_rsk(req)->ipv6_opt);
 483         kfree_skb(inet_rsk(req)->pktopts);
 484 }
 485
 486 #ifdef CONFIG_TCP_MD5SIG
 487 static struct tcp_md5sig_key *tcp_v6_md5_do_lookup(const struct sock *sk,
 488                                                    const struct in6_addr *addr)
 489 {
 490         return tcp_md5_do_lookup(sk, (union tcp_md5_addr *)addr, AF_INET6);
 491 }
 492
 493 static struct tcp_md5sig_key *tcp_v6_md5_lookup(const struct sock *sk,
 494                                                 const struct sock *addr_sk)
 495 {
 496         return tcp_v6_md5_do_lookup(sk, &addr_sk->sk_v6_daddr);
 497 }
 498
 499 static int tcp_v6_parse_md5_keys(struct sock *sk, char __user *optval,
 500                                  int optlen)
 501 {
 502         struct tcp_md5sig cmd;
 503         struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)&cmd.tcpm_addr;
 504
 505         if (optlen < sizeof(cmd))
 506                 return -EINVAL;
 507
 508         if (copy_from_user(&cmd, optval, sizeof(cmd)))
 509                 return -EFAULT;
 510
 511         if (sin6->sin6_family != AF_INET6)
 512                 return -EINVAL;
 513
 514         if (!cmd.tcpm_keylen) {
 515                 if (ipv6_addr_v4mapped(&sin6->sin6_addr))
 516                         return tcp_md5_do_del(sk, (union tcp_md5_addr *)&sin6->sin6_addr.s6_addr32[3],
 517                                               AF_INET);
 518                 return tcp_md5_do_del(sk, (union tcp_md5_addr *)&sin6->sin6_addr,
 519                                       AF_INET6);
 520         }
 521
 522         if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN)
 523                 return -EINVAL;
 524
 525         if (ipv6_addr_v4mapped(&sin6->sin6_addr))
 526                 return tcp_md5_do_add(sk, (union tcp_md5_addr *)&sin6->sin6_addr.s6_addr32[3],
 527                                       AF_INET, cmd.tcpm_key, cmd.tcpm_keylen, GFP_KERNEL);
 528
 529         return tcp_md5_do_add(sk, (union tcp_md5_addr *)&sin6->sin6_addr,
 530                               AF_INET6, cmd.tcpm_key, cmd.tcpm_keylen, GFP_KERNEL);
 531 }
 532
 533 static int tcp_v6_md5_hash_headers(struct tcp_md5sig_pool *hp,
 534                                    const struct in6_addr *daddr,
 535                                    const struct in6_addr *saddr,
 536                                    const struct tcphdr *th, int nbytes)
 537 {
 538         struct tcp6_pseudohdr *bp;
 539         struct scatterlist sg;
 540         struct tcphdr *_th;
 541
 542         bp = hp->scratch;
 543         /* 1. TCP pseudo-header (RFC2460) */
 544         bp->saddr = *saddr;
 545         bp->daddr = *daddr;
 546         bp->protocol = cpu_to_be32(IPPROTO_TCP);
 547         bp->len = cpu_to_be32(nbytes);
 548
 549         _th = (struct tcphdr *)(bp + 1);
 550         memcpy(_th, th, sizeof(*th));
 551         _th->check = 0;
 552
 553         sg_init_one(&sg, bp, sizeof(*bp) + sizeof(*th));
 554         ahash_request_set_crypt(hp->md5_req, &sg, NULL,
 555                                 sizeof(*bp) + sizeof(*th));
 556         return crypto_ahash_update(hp->md5_req);
 557 }
 558
 559 static int tcp_v6_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key,
 560                                const struct in6_addr *daddr, struct in6_addr *saddr,
 561                                const struct tcphdr *th)
 562 {
 563         struct tcp_md5sig_pool *hp;
 564         struct ahash_request *req;
 565
 566         hp = tcp_get_md5sig_pool();
 567         if (!hp)
 568                 goto clear_hash_noput;
 569         req = hp->md5_req;
 570
 571         if (crypto_ahash_init(req))
 572                 goto clear_hash;
 573         if (tcp_v6_md5_hash_headers(hp, daddr, saddr, th, th->doff << 2))
 574                 goto clear_hash;
 575         if (tcp_md5_hash_key(hp, key))
 576                 goto clear_hash;
 577         ahash_request_set_crypt(req, NULL, md5_hash, 0);
 578         if (crypto_ahash_final(req))
 579                 goto clear_hash;
 580
 581         tcp_put_md5sig_pool();
 582         return 0;
 583
 584 clear_hash:
 585         tcp_put_md5sig_pool();
 586 clear_hash_noput:
 587         memset(md5_hash, 0, 16);
 588         return 1;
 589 }
 590
 591 static int tcp_v6_md5_hash_skb(char *md5_hash,
 592                                const struct tcp_md5sig_key *key,
 593                                const struct sock *sk,
 594                                const struct sk_buff *skb)
 595 {
 596         const struct in6_addr *saddr, *daddr;
 597         struct tcp_md5sig_pool *hp;
 598         struct ahash_request *req;
 599         const struct tcphdr *th = tcp_hdr(skb);
 600
 601         if (sk) { /* valid for establish/request sockets */
 602                 saddr = &sk->sk_v6_rcv_saddr;
 603                 daddr = &sk->sk_v6_daddr;
 604         } else {
 605                 const struct ipv6hdr *ip6h = ipv6_hdr(skb);
 606                 saddr = &ip6h->saddr;
 607                 daddr = &ip6h->daddr;
 608         }
 609
 610         hp = tcp_get_md5sig_pool();
 611         if (!hp)
 612                 goto clear_hash_noput;
 613         req = hp->md5_req;
 614
 615         if (crypto_ahash_init(req))
 616                 goto clear_hash;
 617
 618         if (tcp_v6_md5_hash_headers(hp, daddr, saddr, th, skb->len))
 619                 goto clear_hash;
 620         if (tcp_md5_hash_skb_data(hp, skb, th->doff << 2))
 621                 goto clear_hash;
 622         if (tcp_md5_hash_key(hp, key))
 623                 goto clear_hash;
 624         ahash_request_set_crypt(req, NULL, md5_hash, 0);
 625         if (crypto_ahash_final(req))
 626                 goto clear_hash;
 627
 628         tcp_put_md5sig_pool();
 629         return 0;
 630
 631 clear_hash:
 632         tcp_put_md5sig_pool();
 633 clear_hash_noput:
 634         memset(md5_hash, 0, 16);
 635         return 1;
 636 }
 637
 638 #endif
 639
 640 static bool tcp_v6_inbound_md5_hash(const struct sock *sk,
 641                                     const struct sk_buff *skb)
 642 {
 643 #ifdef CONFIG_TCP_MD5SIG
 644         const __u8 *hash_location = NULL;
 645         struct tcp_md5sig_key *hash_expected;
 646         const struct ipv6hdr *ip6h = ipv6_hdr(skb);
 647         const struct tcphdr *th = tcp_hdr(skb);
 648         int genhash;
 649         u8 newhash[16];
 650
 651         hash_expected = tcp_v6_md5_do_lookup(sk, &ip6h->saddr);
 652         hash_location = tcp_parse_md5sig_option(th);
 653
 654         /* We've parsed the options - do we have a hash? */
 655         if (!hash_expected && !hash_location)
 656                 return false;
 657
 658         if (hash_expected && !hash_location) {
 659                 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5NOTFOUND);
 660                 return true;
 661         }
 662
 663         if (!hash_expected && hash_location) {
 664                 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5UNEXPECTED);
 665                 return true;
 666         }
 667
 668         /* check the signature */
 669         genhash = tcp_v6_md5_hash_skb(newhash,
 670                                       hash_expected,
 671                                       NULL, skb);
 672
 673         if (genhash || memcmp(hash_location, newhash, 16) != 0) {
 674                 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5FAILURE);
 675                 net_info_ratelimited("MD5 Hash %s for [%pI6c]:%u->[%pI6c]:%u\n",
 676                                      genhash ? "failed" : "mismatch",
 677                                      &ip6h->saddr, ntohs(th->source),
 678                                      &ip6h->daddr, ntohs(th->dest));
 679                 return true;
 680         }
 681 #endif
 682         return false;
 683 }
 684
 685 static void tcp_v6_init_req(struct request_sock *req,
 686                             const struct sock *sk_listener,
 687                             struct sk_buff *skb)
 688 {
 689         struct inet_request_sock *ireq = inet_rsk(req);
 690         const struct ipv6_pinfo *np = inet6_sk(sk_listener);
 691
 692         ireq->ir_v6_rmt_addr = ipv6_hdr(skb)->saddr;
 693         ireq->ir_v6_loc_addr = ipv6_hdr(skb)->daddr;
 694
 695         /* So that link locals have meaning */
 696         if (!sk_listener->sk_bound_dev_if &&
 697             ipv6_addr_type(&ireq->ir_v6_rmt_addr) & IPV6_ADDR_LINKLOCAL)
 698                 ireq->ir_iif = tcp_v6_iif(skb);
 699
 700         if (!TCP_SKB_CB(skb)->tcp_tw_isn &&
 701             (ipv6_opt_accepted(sk_listener, skb, &TCP_SKB_CB(skb)->header.h6) ||
 702              np->rxopt.bits.rxinfo ||
 703              np->rxopt.bits.rxoinfo || np->rxopt.bits.rxhlim ||
 704              np->rxopt.bits.rxohlim || np->repflow)) {
 705                 atomic_inc(&skb->users);
 706                 ireq->pktopts = skb;
 707         }
 708 }
 709
 710 static struct dst_entry *tcp_v6_route_req(const struct sock *sk,
 711                                           struct flowi *fl,
 712                                           const struct request_sock *req,
 713                                           bool *strict)
 714 {
 715         if (strict)
 716                 *strict = true;
 717         return inet6_csk_route_req(sk, &fl->u.ip6, req, IPPROTO_TCP);
 718 }
 719
 720 struct request_sock_ops tcp6_request_sock_ops __read_mostly = {
 721         .family         =       AF_INET6,
 722         .obj_size       =       sizeof(struct tcp6_request_sock),
 723         .rtx_syn_ack    =       tcp_rtx_synack,
 724         .send_ack       =       tcp_v6_reqsk_send_ack,
 725         .destructor     =       tcp_v6_reqsk_destructor,
 726         .send_reset     =       tcp_v6_send_reset,
 727         .syn_ack_timeout =      tcp_syn_ack_timeout,
 728 };
 729
 730 static const struct tcp_request_sock_ops tcp_request_sock_ipv6_ops = {
 731         .mss_clamp      =       IPV6_MIN_MTU - sizeof(struct tcphdr) -
 732                                 sizeof(struct ipv6hdr),
 733 #ifdef CONFIG_TCP_MD5SIG
 734         .req_md5_lookup =       tcp_v6_md5_lookup,
 735         .calc_md5_hash  =       tcp_v6_md5_hash_skb,
 736 #endif
 737         .init_req       =       tcp_v6_init_req,
 738 #ifdef CONFIG_SYN_COOKIES
 739         .cookie_init_seq =      cookie_v6_init_sequence,
 740 #endif
 741         .route_req      =       tcp_v6_route_req,
 742         .init_seq       =       tcp_v6_init_sequence,
 743         .send_synack    =       tcp_v6_send_synack,
 744 };
 745
 746 static void tcp_v6_send_response(const struct sock *sk, struct sk_buff *skb, u32 seq,
 747                                  u32 ack, u32 win, u32 tsval, u32 tsecr,
 748                                  int oif, struct tcp_md5sig_key *key, int rst,
 749                                  u8 tclass, __be32 label)
 750 {
 751         const struct tcphdr *th = tcp_hdr(skb);
 752         struct tcphdr *t1;
 753         struct sk_buff *buff;
 754         struct flowi6 fl6;
 755         struct net *net = sk ? sock_net(sk) : dev_net(skb_dst(skb)->dev);
 756         struct sock *ctl_sk = net->ipv6.tcp_sk;
 757         unsigned int tot_len = sizeof(struct tcphdr);
 758         struct dst_entry *dst;
 759         __be32 *topt;
 760
 761         if (tsecr)
 762                 tot_len += TCPOLEN_TSTAMP_ALIGNED;
 763 #ifdef CONFIG_TCP_MD5SIG
 764         if (key)
 765                 tot_len += TCPOLEN_MD5SIG_ALIGNED;
 766 #endif
 767
 768         buff = alloc_skb(MAX_HEADER + sizeof(struct ipv6hdr) + tot_len,
 769                          GFP_ATOMIC);
 770         if (!buff)
 771                 return;
 772
 773         skb_reserve(buff, MAX_HEADER + sizeof(struct ipv6hdr) + tot_len);
 774
 775         t1 = (struct tcphdr *) skb_push(buff, tot_len);
 776         skb_reset_transport_header(buff);
 777
 778         /* Swap the send and the receive. */
 779         memset(t1, 0, sizeof(*t1));
 780         t1->dest = th->source;
 781         t1->source = th->dest;
 782         t1->doff = tot_len / 4;
 783         t1->seq = htonl(seq);
 784         t1->ack_seq = htonl(ack);
 785         t1->ack = !rst || !th->ack;
 786         t1->rst = rst;
 787         t1->window = htons(win);
 788
 789         topt = (__be32 *)(t1 + 1);
 790
 791         if (tsecr) {
 792                 *topt++ = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
 793                                 (TCPOPT_TIMESTAMP << 8) | TCPOLEN_TIMESTAMP);
 794                 *topt++ = htonl(tsval);
 795                 *topt++ = htonl(tsecr);
 796         }
 797
 798 #ifdef CONFIG_TCP_MD5SIG
 799         if (key) {
 800                 *topt++ = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
 801                                 (TCPOPT_MD5SIG << 8) | TCPOLEN_MD5SIG);
 802                 tcp_v6_md5_hash_hdr((__u8 *)topt, key,
 803                                     &ipv6_hdr(skb)->saddr,
 804                                     &ipv6_hdr(skb)->daddr, t1);
 805         }
 806 #endif
 807
 808         memset(&fl6, 0, sizeof(fl6));
 809         fl6.daddr = ipv6_hdr(skb)->saddr;
 810         fl6.saddr = ipv6_hdr(skb)->daddr;
 811         fl6.flowlabel = label;
 812
 813         buff->ip_summed = CHECKSUM_PARTIAL;
 814         buff->csum = 0;
 815
 816         __tcp_v6_send_check(buff, &fl6.saddr, &fl6.daddr);
 817
 818         fl6.flowi6_proto = IPPROTO_TCP;
 819         if (rt6_need_strict(&fl6.daddr) && !oif)
 820                 fl6.flowi6_oif = tcp_v6_iif(skb);
 821         else
 822                 fl6.flowi6_oif = oif ? : skb->skb_iif;
 823
 824         fl6.flowi6_mark = IP6_REPLY_MARK(net, skb->mark);
 825         fl6.fl6_dport = t1->dest;
 826         fl6.fl6_sport = t1->source;
 827         security_skb_classify_flow(skb, flowi6_to_flowi(&fl6));
 828
 829         /* Pass a socket to ip6_dst_lookup either it is for RST
 830          * Underlying function will use this to retrieve the network
 831          * namespace
 832          */
 833         dst = ip6_dst_lookup_flow(ctl_sk, &fl6, NULL);
 834         if (!IS_ERR(dst)) {
 835                 skb_dst_set(buff, dst);
 836                 ip6_xmit(ctl_sk, buff, &fl6, NULL, tclass);
 837                 TCP_INC_STATS(net, TCP_MIB_OUTSEGS);
 838                 if (rst)
 839                         TCP_INC_STATS(net, TCP_MIB_OUTRSTS);
 840                 return;
 841         }
 842
 843         kfree_skb(buff);
 844 }
 845
 846 static void tcp_v6_send_reset(const struct sock *sk, struct sk_buff *skb)
 847 {
 848         const struct tcphdr *th = tcp_hdr(skb);
 849         u32 seq = 0, ack_seq = 0;
 850         struct tcp_md5sig_key *key = NULL;
 851 #ifdef CONFIG_TCP_MD5SIG
 852         const __u8 *hash_location = NULL;
 853         struct ipv6hdr *ipv6h = ipv6_hdr(skb);
 854         unsigned char newhash[16];
 855         int genhash;
 856         struct sock *sk1 = NULL;
 857 #endif
 858         int oif;
 859
 860         if (th->rst)
 861                 return;
 862
 863         /* If sk not NULL, it means we did a successful lookup and incoming
 864          * route had to be correct. prequeue might have dropped our dst.
 865          */
 866         if (!sk && !ipv6_unicast_destination(skb))
 867                 return;
 868
 869 #ifdef CONFIG_TCP_MD5SIG
 870         rcu_read_lock();
 871         hash_location = tcp_parse_md5sig_option(th);
 872         if (sk && sk_fullsock(sk)) {
 873                 key = tcp_v6_md5_do_lookup(sk, &ipv6h->saddr);
 874         } else if (hash_location) {
 875                 /*
 876                  * active side is lost. Try to find listening socket through
 877                  * source port, and then find md5 key through listening socket.
 878                  * we are not loose security here:
 879                  * Incoming packet is checked with md5 hash with finding key,
 880                  * no RST generated if md5 hash doesn't match.
 881                  */
 882                 sk1 = inet6_lookup_listener(dev_net(skb_dst(skb)->dev),
 883                                            &tcp_hashinfo, NULL, 0,
 884                                            &ipv6h->saddr,
 885                                            th->source, &ipv6h->daddr,
 886                                            ntohs(th->source), tcp_v6_iif(skb));
 887                 if (!sk1)
 888                         goto out;
 889
 890                 key = tcp_v6_md5_do_lookup(sk1, &ipv6h->saddr);
 891                 if (!key)
 892                         goto out;
 893
 894                 genhash = tcp_v6_md5_hash_skb(newhash, key, NULL, skb);
 895                 if (genhash || memcmp(hash_location, newhash, 16) != 0)
 896                         goto out;
 897         }
 898 #endif
 899
 900         if (th->ack)
 901                 seq = ntohl(th->ack_seq);
 902         else
 903                 ack_seq = ntohl(th->seq) + th->syn + th->fin + skb->len -
 904                           (th->doff << 2);
 905
 906         oif = sk ? sk->sk_bound_dev_if : 0;
 907         tcp_v6_send_response(sk, skb, seq, ack_seq, 0, 0, 0, oif, key, 1, 0, 0);
 908
 909 #ifdef CONFIG_TCP_MD5SIG
 910 out:
 911         rcu_read_unlock();
 912 #endif
 913 }
 914
 915 static void tcp_v6_send_ack(const struct sock *sk, struct sk_buff *skb, u32 seq,
 916                             u32 ack, u32 win, u32 tsval, u32 tsecr, int oif,
 917                             struct tcp_md5sig_key *key, u8 tclass,
 918                             __be32 label)
 919 {
 920         tcp_v6_send_response(sk, skb, seq, ack, win, tsval, tsecr, oif, key, 0,
 921                              tclass, label);
 922 }
 923
 924 static void tcp_v6_timewait_ack(struct sock *sk, struct sk_buff *skb)
 925 {
 926         struct inet_timewait_sock *tw = inet_twsk(sk);
 927         struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
 928
 929         tcp_v6_send_ack(sk, skb, tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
 930                         tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
 931                         tcp_time_stamp + tcptw->tw_ts_offset,
 932                         tcptw->tw_ts_recent, tw->tw_bound_dev_if, tcp_twsk_md5_key(tcptw),
 933                         tw->tw_tclass, cpu_to_be32(tw->tw_flowlabel));
 934
 935         inet_twsk_put(tw);
 936 }
 937
 938 static void tcp_v6_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb,
 939                                   struct request_sock *req)
 940 {
 941         /* sk->sk_state == TCP_LISTEN -> for regular TCP_SYN_RECV
 942          * sk->sk_state == TCP_SYN_RECV -> for Fast Open.
 943          */
 944         /* RFC 7323 2.3
 945          * The window field (SEG.WND) of every outgoing segment, with the
 946          * exception of <SYN> segments, MUST be right-shifted by
 947          * Rcv.Wind.Shift bits:
 948          */
 949         tcp_v6_send_ack(sk, skb, (sk->sk_state == TCP_LISTEN) ?
 950                         tcp_rsk(req)->snt_isn + 1 : tcp_sk(sk)->snd_nxt,
 951                         tcp_rsk(req)->rcv_nxt,
 952                         req->rsk_rcv_wnd >> inet_rsk(req)->rcv_wscale,
 953                         tcp_time_stamp, req->ts_recent, sk->sk_bound_dev_if,
 954                         tcp_v6_md5_do_lookup(sk, &ipv6_hdr(skb)->daddr),
 955                         0, 0);
 956 }
 957
 958
 959 static struct sock *tcp_v6_cookie_check(struct sock *sk, struct sk_buff *skb)
 960 {
 961 #ifdef CONFIG_SYN_COOKIES
 962         const struct tcphdr *th = tcp_hdr(skb);
 963
 964         if (!th->syn)
 965                 sk = cookie_v6_check(sk, skb);
 966 #endif
 967         return sk;
 968 }
 969
 970 static int tcp_v6_conn_request(struct sock *sk, struct sk_buff *skb)
 971 {
 972         if (skb->protocol == htons(ETH_P_IP))
 973                 return tcp_v4_conn_request(sk, skb);
 974
 975         if (!ipv6_unicast_destination(skb))
 976                 goto drop;
 977
 978         return tcp_conn_request(&tcp6_request_sock_ops,
 979                                 &tcp_request_sock_ipv6_ops, sk, skb);
 980
 981 drop:
 982         tcp_listendrop(sk);
 983         return 0; /* don't send reset */
 984 }
 985
 986 static struct sock *tcp_v6_syn_recv_sock(const struct sock *sk, struct sk_buff *skb,
 987                                          struct request_sock *req,
 988                                          struct dst_entry *dst,
 989                                          struct request_sock *req_unhash,
 990                                          bool *own_req)
 991 {
 992         struct inet_request_sock *ireq;
 993         struct ipv6_pinfo *newnp;
 994         const struct ipv6_pinfo *np = inet6_sk(sk);
 995         struct ipv6_txoptions *opt;
 996         struct tcp6_sock *newtcp6sk;
 997         struct inet_sock *newinet;
 998         struct tcp_sock *newtp;
 999         struct sock *newsk;
1000 #ifdef CONFIG_TCP_MD5SIG
1001         struct tcp_md5sig_key *key;
1002 #endif
1003         struct flowi6 fl6;
1004
1005         if (skb->protocol == htons(ETH_P_IP)) {
1006                 /*
1007                  *      v6 mapped
1008                  */
1009
1010                 newsk = tcp_v4_syn_recv_sock(sk, skb, req, dst,
1011                                              req_unhash, own_req);
1012
1013                 if (!newsk)
1014                         return NULL;
1015
1016                 newtcp6sk = (struct tcp6_sock *)newsk;
1017                 inet_sk(newsk)->pinet6 = &newtcp6sk->inet6;
1018
1019                 newinet = inet_sk(newsk);
1020                 newnp = inet6_sk(newsk);
1021                 newtp = tcp_sk(newsk);
1022
1023                 memcpy(newnp, np, sizeof(struct ipv6_pinfo));
1024
1025                 newnp->saddr = newsk->sk_v6_rcv_saddr;
1026
1027                 inet_csk(newsk)->icsk_af_ops = &ipv6_mapped;
1028                 newsk->sk_backlog_rcv = tcp_v4_do_rcv;
1029 #ifdef CONFIG_TCP_MD5SIG
1030                 newtp->af_specific = &tcp_sock_ipv6_mapped_specific;
1031 #endif
1032
1033                 newnp->ipv6_ac_list = NULL;
1034                 newnp->ipv6_fl_list = NULL;
1035                 newnp->pktoptions  = NULL;
1036                 newnp->opt         = NULL;
1037                 newnp->mcast_oif   = tcp_v6_iif(skb);
1038                 newnp->mcast_hops  = ipv6_hdr(skb)->hop_limit;
1039                 newnp->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(skb));
1040                 if (np->repflow)
1041                         newnp->flow_label = ip6_flowlabel(ipv6_hdr(skb));
1042
1043                 /*
1044                  * No need to charge this sock to the relevant IPv6 refcnt debug socks count
1045                  * here, tcp_create_openreq_child now does this for us, see the comment in
1046                  * that function for the gory details. -acme
1047                  */
1048
1049                 /* It is tricky place. Until this moment IPv4 tcp
1050                    worked with IPv6 icsk.icsk_af_ops.
1051                    Sync it now.
1052                  */
1053                 tcp_sync_mss(newsk, inet_csk(newsk)->icsk_pmtu_cookie);
1054
1055                 return newsk;
1056         }
1057
1058         ireq = inet_rsk(req);
1059
1060         if (sk_acceptq_is_full(sk))
1061                 goto out_overflow;
1062
1063         if (!dst) {
1064                 dst = inet6_csk_route_req(sk, &fl6, req, IPPROTO_TCP);
1065                 if (!dst)
1066                         goto out;
1067         }
1068
1069         newsk = tcp_create_openreq_child(sk, req, skb);
1070         if (!newsk)
1071                 goto out_nonewsk;
1072
1073         /*
1074          * No need to charge this sock to the relevant IPv6 refcnt debug socks
1075          * count here, tcp_create_openreq_child now does this for us, see the
1076          * comment in that function for the gory details. -acme
1077          */
1078
1079         newsk->sk_gso_type = SKB_GSO_TCPV6;
1080         ip6_dst_store(newsk, dst, NULL, NULL);
1081         inet6_sk_rx_dst_set(newsk, skb);
1082
1083         newtcp6sk = (struct tcp6_sock *)newsk;
1084         inet_sk(newsk)->pinet6 = &newtcp6sk->inet6;
1085
1086         newtp = tcp_sk(newsk);
1087         newinet = inet_sk(newsk);
1088         newnp = inet6_sk(newsk);
1089
1090         memcpy(newnp, np, sizeof(struct ipv6_pinfo));
1091
1092         newsk->sk_v6_daddr = ireq->ir_v6_rmt_addr;
1093         newnp->saddr = ireq->ir_v6_loc_addr;
1094         newsk->sk_v6_rcv_saddr = ireq->ir_v6_loc_addr;
1095         newsk->sk_bound_dev_if = ireq->ir_iif;
1096
1097         /* Now IPv6 options...
1098
1099            First: no IPv4 options.
1100          */
1101         newinet->inet_opt = NULL;
1102         newnp->ipv6_ac_list = NULL;
1103         newnp->ipv6_fl_list = NULL;
1104
1105         /* Clone RX bits */
1106         newnp->rxopt.all = np->rxopt.all;
1107
1108         newnp->pktoptions = NULL;
1109         newnp->opt        = NULL;
1110         newnp->mcast_oif  = tcp_v6_iif(skb);
1111         newnp->mcast_hops = ipv6_hdr(skb)->hop_limit;
1112         newnp->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(skb));
1113         if (np->repflow)
1114                 newnp->flow_label = ip6_flowlabel(ipv6_hdr(skb));
1115
1116         /* Clone native IPv6 options from listening socket (if any)
1117
1118            Yes, keeping reference count would be much more clever,
1119            but we make one more one thing there: reattach optmem
1120            to newsk.
1121          */
1122         opt = ireq->ipv6_opt;
1123         if (!opt)
1124                 opt = rcu_dereference(np->opt);
1125         if (opt) {
1126                 opt = ipv6_dup_options(newsk, opt);
1127                 RCU_INIT_POINTER(newnp->opt, opt);
1128         }
1129         inet_csk(newsk)->icsk_ext_hdr_len = 0;
1130         if (opt)
1131                 inet_csk(newsk)->icsk_ext_hdr_len = opt->opt_nflen +
1132                                                     opt->opt_flen;
1133
1134         tcp_ca_openreq_child(newsk, dst);
1135
1136         tcp_sync_mss(newsk, dst_mtu(dst));
1137         newtp->advmss = dst_metric_advmss(dst);
1138         if (tcp_sk(sk)->rx_opt.user_mss &&
1139             tcp_sk(sk)->rx_opt.user_mss < newtp->advmss)
1140                 newtp->advmss = tcp_sk(sk)->rx_opt.user_mss;
1141
1142         tcp_initialize_rcv_mss(newsk);
1143
1144         newinet->inet_daddr = newinet->inet_saddr = LOOPBACK4_IPV6;
1145         newinet->inet_rcv_saddr = LOOPBACK4_IPV6;
1146
1147 #ifdef CONFIG_TCP_MD5SIG
1148         /* Copy over the MD5 key from the original socket */
1149         key = tcp_v6_md5_do_lookup(sk, &newsk->sk_v6_daddr);
1150         if (key) {
1151                 /* We're using one, so create a matching key
1152                  * on the newsk structure. If we fail to get
1153                  * memory, then we end up not copying the key
1154                  * across. Shucks.
1155                  */
1156                 tcp_md5_do_add(newsk, (union tcp_md5_addr *)&newsk->sk_v6_daddr,
1157                                AF_INET6, key->key, key->keylen,
1158                                sk_gfp_mask(sk, GFP_ATOMIC));
1159         }
1160 #endif
1161
1162         if (__inet_inherit_port(sk, newsk) < 0) {
1163                 inet_csk_prepare_forced_close(newsk);
1164                 tcp_done(newsk);
1165                 goto out;
1166         }
1167         *own_req = inet_ehash_nolisten(newsk, req_to_sk(req_unhash));
1168         if (*own_req) {
1169                 tcp_move_syn(newtp, req);
1170
1171                 /* Clone pktoptions received with SYN, if we own the req */
1172                 if (ireq->pktopts) {
1173                         newnp->pktoptions = skb_clone(ireq->pktopts,
1174                                                       sk_gfp_mask(sk, GFP_ATOMIC));
1175                         consume_skb(ireq->pktopts);
1176                         ireq->pktopts = NULL;
1177                         if (newnp->pktoptions)
1178                                 skb_set_owner_r(newnp->pktoptions, newsk);
1179                 }
1180         }
1181
1182         return newsk;
1183
1184 out_overflow:
1185         __NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
1186 out_nonewsk:
1187         dst_release(dst);
1188 out:
1189         tcp_listendrop(sk);
1190         return NULL;
1191 }
1192
1193 static void tcp_v6_restore_cb(struct sk_buff *skb)
1194 {
1195         /* We need to move header back to the beginning if xfrm6_policy_check()
1196          * and tcp_v6_fill_cb() are going to be called again.
1197          * ip6_datagram_recv_specific_ctl() also expects IP6CB to be there.
1198          */
1199         memmove(IP6CB(skb), &TCP_SKB_CB(skb)->header.h6,
1200                 sizeof(struct inet6_skb_parm));
1201 }
1202
1203 /* The socket must have it's spinlock held when we get
1204  * here, unless it is a TCP_LISTEN socket.
1205  *
1206  * We have a potential double-lock case here, so even when
1207  * doing backlog processing we use the BH locking scheme.
1208  * This is because we cannot sleep with the original spinlock
1209  * held.
1210  */
1211 static int tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb)
1212 {
1213         struct ipv6_pinfo *np = inet6_sk(sk);
1214         struct tcp_sock *tp;
1215         struct sk_buff *opt_skb = NULL;
1216
1217         /* Imagine: socket is IPv6. IPv4 packet arrives,
1218            goes to IPv4 receive handler and backlogged.
1219            From backlog it always goes here. Kerboom...
1220            Fortunately, tcp_rcv_established and rcv_established
1221            handle them correctly, but it is not case with
1222            tcp_v6_hnd_req and tcp_v6_send_reset().   --ANK
1223          */
1224
1225         if (skb->protocol == htons(ETH_P_IP))
1226                 return tcp_v4_do_rcv(sk, skb);
1227
1228         if (sk_filter(sk, skb))
1229                 goto discard;
1230
1231         /*
1232          *      socket locking is here for SMP purposes as backlog rcv
1233          *      is currently called with bh processing disabled.
1234          */
1235
1236         /* Do Stevens' IPV6_PKTOPTIONS.
1237
1238            Yes, guys, it is the only place in our code, where we
1239            may make it not affecting IPv4.
1240            The rest of code is protocol independent,
1241            and I do not like idea to uglify IPv4.
1242
1243            Actually, all the idea behind IPV6_PKTOPTIONS
1244            looks not very well thought. For now we latch
1245            options, received in the last packet, enqueued
1246            by tcp. Feel free to propose better solution.
1247                                                --ANK (980728)
1248          */
1249         if (np->rxopt.all)
1250                 opt_skb = skb_clone(skb, sk_gfp_mask(sk, GFP_ATOMIC));
1251
1252         if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
1253                 struct dst_entry *dst = sk->sk_rx_dst;
1254
1255                 sock_rps_save_rxhash(sk, skb);
1256                 sk_mark_napi_id(sk, skb);
1257                 if (dst) {
1258                         if (inet_sk(sk)->rx_dst_ifindex != skb->skb_iif ||
1259                             dst->ops->check(dst, np->rx_dst_cookie) == NULL) {
1260                                 dst_release(dst);
1261                                 sk->sk_rx_dst = NULL;
1262                         }
1263                 }
1264
1265                 tcp_rcv_established(sk, skb, tcp_hdr(skb), skb->len);
1266                 if (opt_skb)
1267                         goto ipv6_pktoptions;
1268                 return 0;
1269         }
1270
1271         if (tcp_checksum_complete(skb))
1272                 goto csum_err;
1273
1274         if (sk->sk_state == TCP_LISTEN) {
1275                 struct sock *nsk = tcp_v6_cookie_check(sk, skb);
1276
1277                 if (!nsk)
1278                         goto discard;
1279
1280                 if (nsk != sk) {
1281                         sock_rps_save_rxhash(nsk, skb);
1282                         sk_mark_napi_id(nsk, skb);
1283                         if (tcp_child_process(sk, nsk, skb))
1284                                 goto reset;
1285                         if (opt_skb)
1286                                 __kfree_skb(opt_skb);
1287                         return 0;
1288                 }
1289         } else
1290                 sock_rps_save_rxhash(sk, skb);
1291
1292         if (tcp_rcv_state_process(sk, skb))
1293                 goto reset;
1294         if (opt_skb)
1295                 goto ipv6_pktoptions;
1296         return 0;
1297
1298 reset:
1299         tcp_v6_send_reset(sk, skb);
1300 discard:
1301         if (opt_skb)
1302                 __kfree_skb(opt_skb);
1303         kfree_skb(skb);
1304         return 0;
1305 csum_err:
1306         TCP_INC_STATS(sock_net(sk), TCP_MIB_CSUMERRORS);
1307         TCP_INC_STATS(sock_net(sk), TCP_MIB_INERRS);
1308         goto discard;
1309
1310
1311 ipv6_pktoptions:
1312         /* Do you ask, what is it?
1313
1314            1. skb was enqueued by tcp.
1315            2. skb is added to tail of read queue, rather than out of order.
1316            3. socket is not in passive state.
1317            4. Finally, it really contains options, which user wants to receive.
1318          */
1319         tp = tcp_sk(sk);
1320         if (TCP_SKB_CB(opt_skb)->end_seq == tp->rcv_nxt &&
1321             !((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN))) {
1322                 if (np->rxopt.bits.rxinfo || np->rxopt.bits.rxoinfo)
1323                         np->mcast_oif = tcp_v6_iif(opt_skb);
1324                 if (np->rxopt.bits.rxhlim || np->rxopt.bits.rxohlim)
1325                         np->mcast_hops = ipv6_hdr(opt_skb)->hop_limit;
1326                 if (np->rxopt.bits.rxflow || np->rxopt.bits.rxtclass)
1327                         np->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(opt_skb));
1328                 if (np->repflow)
1329                         np->flow_label = ip6_flowlabel(ipv6_hdr(opt_skb));
1330                 if (ipv6_opt_accepted(sk, opt_skb, &TCP_SKB_CB(opt_skb)->header.h6)) {
1331                         skb_set_owner_r(opt_skb, sk);
1332                         tcp_v6_restore_cb(opt_skb);
1333                         opt_skb = xchg(&np->pktoptions, opt_skb);
1334                 } else {
1335                         __kfree_skb(opt_skb);
1336                         opt_skb = xchg(&np->pktoptions, NULL);
1337                 }
1338         }
1339
1340         kfree_skb(opt_skb);
1341         return 0;
1342 }
1343
1344 static void tcp_v6_fill_cb(struct sk_buff *skb, const struct ipv6hdr *hdr,
1345                            const struct tcphdr *th)
1346 {
1347         /* This is tricky: we move IP6CB at its correct location into
1348          * TCP_SKB_CB(). It must be done after xfrm6_policy_check(), because
1349          * _decode_session6() uses IP6CB().
1350          * barrier() makes sure compiler won't play aliasing games.
1351          */
1352         memmove(&TCP_SKB_CB(skb)->header.h6, IP6CB(skb),
1353                 sizeof(struct inet6_skb_parm));
1354         barrier();
1355
1356         TCP_SKB_CB(skb)->seq = ntohl(th->seq);
1357         TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
1358                                     skb->len - th->doff*4);
1359         TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
1360         TCP_SKB_CB(skb)->tcp_flags = tcp_flag_byte(th);
1361         TCP_SKB_CB(skb)->tcp_tw_isn = 0;
1362         TCP_SKB_CB(skb)->ip_dsfield = ipv6_get_dsfield(hdr);
1363         TCP_SKB_CB(skb)->sacked = 0;
1364 }
1365
1366 static int tcp_v6_rcv(struct sk_buff *skb)
1367 {
1368         const struct tcphdr *th;
1369         const struct ipv6hdr *hdr;
1370         bool refcounted;
1371         struct sock *sk;
1372         int ret;
1373         struct net *net = dev_net(skb->dev);
1374
1375         if (skb->pkt_type != PACKET_HOST)
1376                 goto discard_it;
1377
1378         /*
1379          *      Count it even if it's bad.
1380          */
1381         __TCP_INC_STATS(net, TCP_MIB_INSEGS);
1382
1383         if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
1384                 goto discard_it;
1385
1386         th = (const struct tcphdr *)skb->data;
1387
1388         if (unlikely(th->doff < sizeof(struct tcphdr)/4))
1389                 goto bad_packet;
1390         if (!pskb_may_pull(skb, th->doff*4))
1391                 goto discard_it;
1392
1393         if (skb_checksum_init(skb, IPPROTO_TCP, ip6_compute_pseudo))
1394                 goto csum_error;
1395
1396         th = (const struct tcphdr *)skb->data;
1397         hdr = ipv6_hdr(skb);
1398
1399 lookup:
1400         sk = __inet6_lookup_skb(&tcp_hashinfo, skb, __tcp_hdrlen(th),
1401                                 th->source, th->dest, inet6_iif(skb),
1402                                 &refcounted);
1403         if (!sk)
1404                 goto no_tcp_socket;
1405
1406 process:
1407         if (sk->sk_state == TCP_TIME_WAIT)
1408                 goto do_time_wait;
1409
1410         if (sk->sk_state == TCP_NEW_SYN_RECV) {
1411                 struct request_sock *req = inet_reqsk(sk);
1412                 struct sock *nsk;
1413
1414                 sk = req->rsk_listener;
1415                 tcp_v6_fill_cb(skb, hdr, th);
1416                 if (tcp_v6_inbound_md5_hash(sk, skb)) {
1417                         sk_drops_add(sk, skb);
1418                         reqsk_put(req);
1419                         goto discard_it;
1420                 }
1421                 if (unlikely(sk->sk_state != TCP_LISTEN)) {
1422                         inet_csk_reqsk_queue_drop_and_put(sk, req);
1423                         goto lookup;
1424                 }
1425                 sock_hold(sk);
1426                 refcounted = true;
1427                 nsk = tcp_check_req(sk, skb, req, false);
1428                 if (!nsk) {
1429                         reqsk_put(req);
1430                         goto discard_and_relse;
1431                 }
1432                 if (nsk == sk) {
1433                         reqsk_put(req);
1434                         tcp_v6_restore_cb(skb);
1435                 } else if (tcp_child_process(sk, nsk, skb)) {
1436                         tcp_v6_send_reset(nsk, skb);
1437                         goto discard_and_relse;
1438                 } else {
1439                         sock_put(sk);
1440                         return 0;
1441                 }
1442         }
1443         if (hdr->hop_limit < inet6_sk(sk)->min_hopcount) {
1444                 __NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP);
1445                 goto discard_and_relse;
1446         }
1447
1448         if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb))
1449                 goto discard_and_relse;
1450
1451         tcp_v6_fill_cb(skb, hdr, th);
1452
1453         if (tcp_v6_inbound_md5_hash(sk, skb))
1454                 goto discard_and_relse;
1455
1456         if (sk_filter(sk, skb))
1457                 goto discard_and_relse;
1458
1459         skb->dev = NULL;
1460
1461         if (sk->sk_state == TCP_LISTEN) {
1462                 ret = tcp_v6_do_rcv(sk, skb);
1463                 goto put_and_return;
1464         }
1465
1466         sk_incoming_cpu_update(sk);
1467
1468         bh_lock_sock_nested(sk);
1469         tcp_segs_in(tcp_sk(sk), skb);
1470         ret = 0;
1471         if (!sock_owned_by_user(sk)) {
1472                 if (!tcp_prequeue(sk, skb))
1473                         ret = tcp_v6_do_rcv(sk, skb);
1474         } else if (tcp_add_backlog(sk, skb)) {
1475                 goto discard_and_relse;
1476         }
1477         bh_unlock_sock(sk);
1478
1479 put_and_return:
1480         if (refcounted)
1481                 sock_put(sk);
1482         return ret ? -1 : 0;
1483
1484 no_tcp_socket:
1485         if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb))
1486                 goto discard_it;
1487
1488         tcp_v6_fill_cb(skb, hdr, th);
1489
1490         if (tcp_checksum_complete(skb)) {
1491 csum_error:
1492                 __TCP_INC_STATS(net, TCP_MIB_CSUMERRORS);
1493 bad_packet:
1494                 __TCP_INC_STATS(net, TCP_MIB_INERRS);
1495         } else {
1496                 tcp_v6_send_reset(NULL, skb);
1497         }
1498
1499 discard_it:
1500         kfree_skb(skb);
1501         return 0;
1502
1503 discard_and_relse:
1504         sk_drops_add(sk, skb);
1505         if (refcounted)
1506                 sock_put(sk);
1507         goto discard_it;
1508
1509 do_time_wait:
1510         if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
1511                 inet_twsk_put(inet_twsk(sk));
1512                 goto discard_it;
1513         }
1514
1515         tcp_v6_fill_cb(skb, hdr, th);
1516
1517         if (tcp_checksum_complete(skb)) {
1518                 inet_twsk_put(inet_twsk(sk));
1519                 goto csum_error;
1520         }
1521
1522         switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) {
1523         case TCP_TW_SYN:
1524         {
1525                 struct sock *sk2;
1526
1527                 sk2 = inet6_lookup_listener(dev_net(skb->dev), &tcp_hashinfo,
1528                                             skb, __tcp_hdrlen(th),
1529                                             &ipv6_hdr(skb)->saddr, th->source,
1530                                             &ipv6_hdr(skb)->daddr,
1531                                             ntohs(th->dest), tcp_v6_iif(skb));
1532                 if (sk2) {
1533                         struct inet_timewait_sock *tw = inet_twsk(sk);
1534                         inet_twsk_deschedule_put(tw);
1535                         sk = sk2;
1536                         tcp_v6_restore_cb(skb);
1537                         refcounted = false;
1538                         goto process;
1539                 }
1540                 /* Fall through to ACK */
1541         }
1542         case TCP_TW_ACK:
1543                 tcp_v6_timewait_ack(sk, skb);
1544                 break;
1545         case TCP_TW_RST:
1546                 tcp_v6_restore_cb(skb);
1547                 tcp_v6_send_reset(sk, skb);
1548                 inet_twsk_deschedule_put(inet_twsk(sk));
1549                 goto discard_it;
1550         case TCP_TW_SUCCESS:
1551                 ;
1552         }
1553         goto discard_it;
1554 }
1555
1556 static void tcp_v6_early_demux(struct sk_buff *skb)
1557 {
1558         const struct ipv6hdr *hdr;
1559         const struct tcphdr *th;
1560         struct sock *sk;
1561
1562         if (skb->pkt_type != PACKET_HOST)
1563                 return;
1564
1565         if (!pskb_may_pull(skb, skb_transport_offset(skb) + sizeof(struct tcphdr)))
1566                 return;
1567
1568         hdr = ipv6_hdr(skb);
1569         th = tcp_hdr(skb);
1570
1571         if (th->doff < sizeof(struct tcphdr) / 4)
1572                 return;
1573
1574         /* Note : We use inet6_iif() here, not tcp_v6_iif() */
1575         sk = __inet6_lookup_established(dev_net(skb->dev), &tcp_hashinfo,
1576                                         &hdr->saddr, th->source,
1577                                         &hdr->daddr, ntohs(th->dest),
1578                                         inet6_iif(skb));
1579         if (sk) {
1580                 skb->sk = sk;
1581                 skb->destructor = sock_edemux;
1582                 if (sk_fullsock(sk)) {
1583                         struct dst_entry *dst = READ_ONCE(sk->sk_rx_dst);
1584
1585                         if (dst)
1586                                 dst = dst_check(dst, inet6_sk(sk)->rx_dst_cookie);
1587                         if (dst &&
1588                             inet_sk(sk)->rx_dst_ifindex == skb->skb_iif)
1589                                 skb_dst_set_noref(skb, dst);
1590                 }
1591         }
1592 }
1593
1594 static struct timewait_sock_ops tcp6_timewait_sock_ops = {
1595         .twsk_obj_size  = sizeof(struct tcp6_timewait_sock),
1596         .twsk_unique    = tcp_twsk_unique,
1597         .twsk_destructor = tcp_twsk_destructor,
1598 };
1599
1600 static const struct inet_connection_sock_af_ops ipv6_specific = {
1601         .queue_xmit        = inet6_csk_xmit,
1602         .send_check        = tcp_v6_send_check,
1603         .rebuild_header    = inet6_sk_rebuild_header,
1604         .sk_rx_dst_set     = inet6_sk_rx_dst_set,
1605         .conn_request      = tcp_v6_conn_request,
1606         .syn_recv_sock     = tcp_v6_syn_recv_sock,
1607         .net_header_len    = sizeof(struct ipv6hdr),
1608         .net_frag_header_len = sizeof(struct frag_hdr),
1609         .setsockopt        = ipv6_setsockopt,
1610         .getsockopt        = ipv6_getsockopt,
1611         .addr2sockaddr     = inet6_csk_addr2sockaddr,
1612         .sockaddr_len      = sizeof(struct sockaddr_in6),
1613         .bind_conflict     = inet6_csk_bind_conflict,
1614 #ifdef CONFIG_COMPAT
1615         .compat_setsockopt = compat_ipv6_setsockopt,
1616         .compat_getsockopt = compat_ipv6_getsockopt,
1617 #endif
1618         .mtu_reduced       = tcp_v6_mtu_reduced,
1619 };
1620
1621 #ifdef CONFIG_TCP_MD5SIG
1622 static const struct tcp_sock_af_ops tcp_sock_ipv6_specific = {
1623         .md5_lookup     =       tcp_v6_md5_lookup,
1624         .calc_md5_hash  =       tcp_v6_md5_hash_skb,
1625         .md5_parse      =       tcp_v6_parse_md5_keys,
1626 };
1627 #endif
1628
1629 /*
1630  *      TCP over IPv4 via INET6 API
1631  */
1632 static const struct inet_connection_sock_af_ops ipv6_mapped = {
1633         .queue_xmit        = ip_queue_xmit,
1634         .send_check        = tcp_v4_send_check,
1635         .rebuild_header    = inet_sk_rebuild_header,
1636         .sk_rx_dst_set     = inet_sk_rx_dst_set,
1637         .conn_request      = tcp_v6_conn_request,
1638         .syn_recv_sock     = tcp_v6_syn_recv_sock,
1639         .net_header_len    = sizeof(struct iphdr),
1640         .setsockopt        = ipv6_setsockopt,
1641         .getsockopt        = ipv6_getsockopt,
1642         .addr2sockaddr     = inet6_csk_addr2sockaddr,
1643         .sockaddr_len      = sizeof(struct sockaddr_in6),
1644         .bind_conflict     = inet6_csk_bind_conflict,
1645 #ifdef CONFIG_COMPAT
1646         .compat_setsockopt = compat_ipv6_setsockopt,
1647         .compat_getsockopt = compat_ipv6_getsockopt,
1648 #endif
1649         .mtu_reduced       = tcp_v4_mtu_reduced,
1650 };
1651
1652 #ifdef CONFIG_TCP_MD5SIG
1653 static const struct tcp_sock_af_ops tcp_sock_ipv6_mapped_specific = {
1654         .md5_lookup     =       tcp_v4_md5_lookup,
1655         .calc_md5_hash  =       tcp_v4_md5_hash_skb,
1656         .md5_parse      =       tcp_v6_parse_md5_keys,
1657 };
1658 #endif
1659
1660 /* NOTE: A lot of things set to zero explicitly by call to
1661  *       sk_alloc() so need not be done here.
1662  */
1663 static int tcp_v6_init_sock(struct sock *sk)
1664 {
1665         struct inet_connection_sock *icsk = inet_csk(sk);
1666
1667         tcp_init_sock(sk);
1668
1669         icsk->icsk_af_ops = &ipv6_specific;
1670
1671 #ifdef CONFIG_TCP_MD5SIG
1672         tcp_sk(sk)->af_specific = &tcp_sock_ipv6_specific;
1673 #endif
1674
1675         return 0;
1676 }
1677
1678 static void tcp_v6_destroy_sock(struct sock *sk)
1679 {
1680         tcp_v4_destroy_sock(sk);
1681         inet6_destroy_sock(sk);
1682 }
1683
1684 #ifdef CONFIG_PROC_FS
1685 /* Proc filesystem TCPv6 sock list dumping. */
1686 static void get_openreq6(struct seq_file *seq,
1687                          const struct request_sock *req, int i)
1688 {
1689         long ttd = req->rsk_timer.expires - jiffies;
1690         const struct in6_addr *src = &inet_rsk(req)->ir_v6_loc_addr;
1691         const struct in6_addr *dest = &inet_rsk(req)->ir_v6_rmt_addr;
1692
1693         if (ttd < 0)
1694                 ttd = 0;
1695
1696         seq_printf(seq,
1697                    "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
1698                    "%02X %08X:%08X %02X:%08lX %08X %5u %8d %d %d %pK\n",
1699                    i,
1700                    src->s6_addr32[0], src->s6_addr32[1],
1701                    src->s6_addr32[2], src->s6_addr32[3],
1702                    inet_rsk(req)->ir_num,
1703                    dest->s6_addr32[0], dest->s6_addr32[1],
1704                    dest->s6_addr32[2], dest->s6_addr32[3],
1705                    ntohs(inet_rsk(req)->ir_rmt_port),
1706                    TCP_SYN_RECV,
1707                    0, 0, /* could print option size, but that is af dependent. */
1708                    1,   /* timers active (only the expire timer) */
1709                    jiffies_to_clock_t(ttd),
1710                    req->num_timeout,
1711                    from_kuid_munged(seq_user_ns(seq),
1712                                     sock_i_uid(req->rsk_listener)),
1713                    0,  /* non standard timer */
1714                    0, /* open_requests have no inode */
1715                    0, req);
1716 }
1717
1718 static void get_tcp6_sock(struct seq_file *seq, struct sock *sp, int i)
1719 {
1720         const struct in6_addr *dest, *src;
1721         __u16 destp, srcp;
1722         int timer_active;
1723         unsigned long timer_expires;
1724         const struct inet_sock *inet = inet_sk(sp);
1725         const struct tcp_sock *tp = tcp_sk(sp);
1726         const struct inet_connection_sock *icsk = inet_csk(sp);
1727         const struct fastopen_queue *fastopenq = &icsk->icsk_accept_queue.fastopenq;
1728         int rx_queue;
1729         int state;
1730
1731         dest  = &sp->sk_v6_daddr;
1732         src   = &sp->sk_v6_rcv_saddr;
1733         destp = ntohs(inet->inet_dport);
1734         srcp  = ntohs(inet->inet_sport);
1735
1736         if (icsk->icsk_pending == ICSK_TIME_RETRANS ||
1737             icsk->icsk_pending == ICSK_TIME_EARLY_RETRANS ||
1738             icsk->icsk_pending == ICSK_TIME_LOSS_PROBE) {
1739                 timer_active    = 1;
1740                 timer_expires   = icsk->icsk_timeout;
1741         } else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
1742                 timer_active    = 4;
1743                 timer_expires   = icsk->icsk_timeout;
1744         } else if (timer_pending(&sp->sk_timer)) {
1745                 timer_active    = 2;
1746                 timer_expires   = sp->sk_timer.expires;
1747         } else {
1748                 timer_active    = 0;
1749                 timer_expires = jiffies;
1750         }
1751
1752         state = sk_state_load(sp);
1753         if (state == TCP_LISTEN)
1754                 rx_queue = sp->sk_ack_backlog;
1755         else
1756                 /* Because we don't lock the socket,
1757                  * we might find a transient negative value.
1758                  */
1759                 rx_queue = max_t(int, tp->rcv_nxt - tp->copied_seq, 0);
1760
1761         seq_printf(seq,
1762                    "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
1763                    "%02X %08X:%08X %02X:%08lX %08X %5u %8d %lu %d %pK %lu %lu %u %u %d\n",
1764                    i,
1765                    src->s6_addr32[0], src->s6_addr32[1],
1766                    src->s6_addr32[2], src->s6_addr32[3], srcp,
1767                    dest->s6_addr32[0], dest->s6_addr32[1],
1768                    dest->s6_addr32[2], dest->s6_addr32[3], destp,
1769                    state,
1770                    tp->write_seq - tp->snd_una,
1771                    rx_queue,
1772                    timer_active,
1773                    jiffies_delta_to_clock_t(timer_expires - jiffies),
1774                    icsk->icsk_retransmits,
1775                    from_kuid_munged(seq_user_ns(seq), sock_i_uid(sp)),
1776                    icsk->icsk_probes_out,
1777                    sock_i_ino(sp),
1778                    atomic_read(&sp->sk_refcnt), sp,
1779                    jiffies_to_clock_t(icsk->icsk_rto),
1780                    jiffies_to_clock_t(icsk->icsk_ack.ato),
1781                    (icsk->icsk_ack.quick << 1) | icsk->icsk_ack.pingpong,
1782                    tp->snd_cwnd,
1783                    state == TCP_LISTEN ?
1784                         fastopenq->max_qlen :
1785                         (tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh)
1786                    );
1787 }
1788
1789 static void get_timewait6_sock(struct seq_file *seq,
1790                                struct inet_timewait_sock *tw, int i)
1791 {
1792         long delta = tw->tw_timer.expires - jiffies;
1793         const struct in6_addr *dest, *src;
1794         __u16 destp, srcp;
1795
1796         dest = &tw->tw_v6_daddr;
1797         src  = &tw->tw_v6_rcv_saddr;
1798         destp = ntohs(tw->tw_dport);
1799         srcp  = ntohs(tw->tw_sport);
1800
1801         seq_printf(seq,
1802                    "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
1803                    "%02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK\n",
1804                    i,
1805                    src->s6_addr32[0], src->s6_addr32[1],
1806                    src->s6_addr32[2], src->s6_addr32[3], srcp,
1807                    dest->s6_addr32[0], dest->s6_addr32[1],
1808                    dest->s6_addr32[2], dest->s6_addr32[3], destp,
1809                    tw->tw_substate, 0, 0,
1810                    3, jiffies_delta_to_clock_t(delta), 0, 0, 0, 0,
1811                    atomic_read(&tw->tw_refcnt), tw);
1812 }
1813
1814 static int tcp6_seq_show(struct seq_file *seq, void *v)
1815 {
1816         struct tcp_iter_state *st;
1817         struct sock *sk = v;
1818
1819         if (v == SEQ_START_TOKEN) {
1820                 seq_puts(seq,
1821                          "  sl  "
1822                          "local_address                         "
1823                          "remote_address                        "
1824                          "st tx_queue rx_queue tr tm->when retrnsmt"
1825                          "   uid  timeout inode\n");
1826                 goto out;
1827         }
1828         st = seq->private;
1829
1830         if (sk->sk_state == TCP_TIME_WAIT)
1831                 get_timewait6_sock(seq, v, st->num);
1832         else if (sk->sk_state == TCP_NEW_SYN_RECV)
1833                 get_openreq6(seq, v, st->num);
1834         else
1835                 get_tcp6_sock(seq, v, st->num);
1836 out:
1837         return 0;
1838 }
1839
1840 static const struct file_operations tcp6_afinfo_seq_fops = {
1841         .owner   = THIS_MODULE,
1842         .open    = tcp_seq_open,
1843         .read    = seq_read,
1844         .llseek  = seq_lseek,
1845         .release = seq_release_net
1846 };
1847
1848 static struct tcp_seq_afinfo tcp6_seq_afinfo = {
1849         .name           = "tcp6",
1850         .family         = AF_INET6,
1851         .seq_fops       = &tcp6_afinfo_seq_fops,
1852         .seq_ops        = {
1853                 .show           = tcp6_seq_show,
1854         },
1855 };
1856
1857 int __net_init tcp6_proc_init(struct net *net)
1858 {
1859         return tcp_proc_register(net, &tcp6_seq_afinfo);
1860 }
1861
1862 void tcp6_proc_exit(struct net *net)
1863 {
1864         tcp_proc_unregister(net, &tcp6_seq_afinfo);
1865 }
1866 #endif
1867
1868 struct proto tcpv6_prot = {
1869         .name                   = "TCPv6",
1870         .owner                  = THIS_MODULE,
1871         .close                  = tcp_close,
1872         .connect                = tcp_v6_connect,
1873         .disconnect             = tcp_disconnect,
1874         .accept                 = inet_csk_accept,
1875         .ioctl                  = tcp_ioctl,
1876         .init                   = tcp_v6_init_sock,
1877         .destroy                = tcp_v6_destroy_sock,
1878         .shutdown               = tcp_shutdown,
1879         .setsockopt             = tcp_setsockopt,
1880         .getsockopt             = tcp_getsockopt,
1881         .recvmsg                = tcp_recvmsg,
1882         .sendmsg                = tcp_sendmsg,
1883         .sendpage               = tcp_sendpage,
1884         .backlog_rcv            = tcp_v6_do_rcv,
1885         .release_cb             = tcp_release_cb,
1886         .hash                   = inet6_hash,
1887         .unhash                 = inet_unhash,
1888         .get_port               = inet_csk_get_port,
1889         .enter_memory_pressure  = tcp_enter_memory_pressure,
1890         .stream_memory_free     = tcp_stream_memory_free,
1891         .sockets_allocated      = &tcp_sockets_allocated,
1892         .memory_allocated       = &tcp_memory_allocated,
1893         .memory_pressure        = &tcp_memory_pressure,
1894         .orphan_count           = &tcp_orphan_count,
1895         .sysctl_mem             = sysctl_tcp_mem,
1896         .sysctl_wmem            = sysctl_tcp_wmem,
1897         .sysctl_rmem            = sysctl_tcp_rmem,
1898         .max_header             = MAX_TCP_HEADER,
1899         .obj_size               = sizeof(struct tcp6_sock),
1900         .slab_flags             = SLAB_DESTROY_BY_RCU,
1901         .twsk_prot              = &tcp6_timewait_sock_ops,
1902         .rsk_prot               = &tcp6_request_sock_ops,
1903         .h.hashinfo             = &tcp_hashinfo,
1904         .no_autobind            = true,
1905 #ifdef CONFIG_COMPAT
1906         .compat_setsockopt      = compat_tcp_setsockopt,
1907         .compat_getsockopt      = compat_tcp_getsockopt,
1908 #endif
1909         .diag_destroy           = tcp_abort,
1910 };
1911
1912 static const struct inet6_protocol tcpv6_protocol = {
1913         .early_demux    =       tcp_v6_early_demux,
1914         .handler        =       tcp_v6_rcv,
1915         .err_handler    =       tcp_v6_err,
1916         .flags          =       INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
1917 };
1918
1919 static struct inet_protosw tcpv6_protosw = {
1920         .type           =       SOCK_STREAM,
1921         .protocol       =       IPPROTO_TCP,
1922         .prot           =       &tcpv6_prot,
1923         .ops            =       &inet6_stream_ops,
1924         .flags          =       INET_PROTOSW_PERMANENT |
1925                                 INET_PROTOSW_ICSK,
1926 };
1927
1928 static int __net_init tcpv6_net_init(struct net *net)
1929 {
1930         return inet_ctl_sock_create(&net->ipv6.tcp_sk, PF_INET6,
1931                                     SOCK_RAW, IPPROTO_TCP, net);
1932 }
1933
1934 static void __net_exit tcpv6_net_exit(struct net *net)
1935 {
1936         inet_ctl_sock_destroy(net->ipv6.tcp_sk);
1937 }
1938
1939 static void __net_exit tcpv6_net_exit_batch(struct list_head *net_exit_list)
1940 {
1941         inet_twsk_purge(&tcp_hashinfo, &tcp_death_row, AF_INET6);
1942 }
1943
1944 static struct pernet_operations tcpv6_net_ops = {
1945         .init       = tcpv6_net_init,
1946         .exit       = tcpv6_net_exit,
1947         .exit_batch = tcpv6_net_exit_batch,
1948 };
1949
1950 int __init tcpv6_init(void)
1951 {
1952         int ret;
1953
1954         ret = inet6_add_protocol(&tcpv6_protocol, IPPROTO_TCP);
1955         if (ret)
1956                 goto out;
1957
1958         /* register inet6 protocol */
1959         ret = inet6_register_protosw(&tcpv6_protosw);
1960         if (ret)
1961                 goto out_tcpv6_protocol;
1962
1963         ret = register_pernet_subsys(&tcpv6_net_ops);
1964         if (ret)
1965                 goto out_tcpv6_protosw;
1966 out:
1967         return ret;
1968
1969 out_tcpv6_protosw:
1970         inet6_unregister_protosw(&tcpv6_protosw);
1971 out_tcpv6_protocol:
1972         inet6_del_protocol(&tcpv6_protocol, IPPROTO_TCP);
1973         goto out;
1974 }
1975
1976 void tcpv6_exit(void)
1977 {
1978         unregister_pernet_subsys(&tcpv6_net_ops);
1979         inet6_unregister_protosw(&tcpv6_protosw);
1980         inet6_del_protocol(&tcpv6_protocol, IPPROTO_TCP);
1981 }