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_info_ratelimited("MD5 Hash %s for [%pI6c]:%u->[%pI6c]:%u\n",
 675                                      genhash ? "failed" : "mismatch",
 676                                      &ip6h->saddr, ntohs(th->source),
 677                                      &ip6h->daddr, ntohs(th->dest));
 678                 return true;
 679         }
 680 #endif
 681         return false;
 682 }
 683
 684 static void tcp_v6_init_req(struct request_sock *req,
 685                             const struct sock *sk_listener,
 686                             struct sk_buff *skb)
 687 {
 688         struct inet_request_sock *ireq = inet_rsk(req);
 689         const struct ipv6_pinfo *np = inet6_sk(sk_listener);
 690
 691         ireq->ir_v6_rmt_addr = ipv6_hdr(skb)->saddr;
 692         ireq->ir_v6_loc_addr = ipv6_hdr(skb)->daddr;
 693
 694         /* So that link locals have meaning */
 695         if (!sk_listener->sk_bound_dev_if &&
 696             ipv6_addr_type(&ireq->ir_v6_rmt_addr) & IPV6_ADDR_LINKLOCAL)
 697                 ireq->ir_iif = tcp_v6_iif(skb);
 698
 699         if (!TCP_SKB_CB(skb)->tcp_tw_isn &&
 700             (ipv6_opt_accepted(sk_listener, skb, &TCP_SKB_CB(skb)->header.h6) ||
 701              np->rxopt.bits.rxinfo ||
 702              np->rxopt.bits.rxoinfo || np->rxopt.bits.rxhlim ||
 703              np->rxopt.bits.rxohlim || np->repflow)) {
 704                 atomic_inc(&skb->users);
 705                 ireq->pktopts = skb;
 706         }
 707 }
 708
 709 static struct dst_entry *tcp_v6_route_req(const struct sock *sk,
 710                                           struct flowi *fl,
 711                                           const struct request_sock *req,
 712                                           bool *strict)
 713 {
 714         if (strict)
 715                 *strict = true;
 716         return inet6_csk_route_req(sk, &fl->u.ip6, req, IPPROTO_TCP);
 717 }
 718
 719 struct request_sock_ops tcp6_request_sock_ops __read_mostly = {
 720         .family         =       AF_INET6,
 721         .obj_size       =       sizeof(struct tcp6_request_sock),
 722         .rtx_syn_ack    =       tcp_rtx_synack,
 723         .send_ack       =       tcp_v6_reqsk_send_ack,
 724         .destructor     =       tcp_v6_reqsk_destructor,
 725         .send_reset     =       tcp_v6_send_reset,
 726         .syn_ack_timeout =      tcp_syn_ack_timeout,
 727 };
 728
 729 static const struct tcp_request_sock_ops tcp_request_sock_ipv6_ops = {
 730         .mss_clamp      =       IPV6_MIN_MTU - sizeof(struct tcphdr) -
 731                                 sizeof(struct ipv6hdr),
 732 #ifdef CONFIG_TCP_MD5SIG
 733         .req_md5_lookup =       tcp_v6_md5_lookup,
 734         .calc_md5_hash  =       tcp_v6_md5_hash_skb,
 735 #endif
 736         .init_req       =       tcp_v6_init_req,
 737 #ifdef CONFIG_SYN_COOKIES
 738         .cookie_init_seq =      cookie_v6_init_sequence,
 739 #endif
 740         .route_req      =       tcp_v6_route_req,
 741         .init_seq       =       tcp_v6_init_sequence,
 742         .send_synack    =       tcp_v6_send_synack,
 743 };
 744
 745 static void tcp_v6_send_response(const struct sock *sk, struct sk_buff *skb, u32 seq,
 746                                  u32 ack, u32 win, u32 tsval, u32 tsecr,
 747                                  int oif, struct tcp_md5sig_key *key, int rst,
 748                                  u8 tclass, __be32 label)
 749 {
 750         const struct tcphdr *th = tcp_hdr(skb);
 751         struct tcphdr *t1;
 752         struct sk_buff *buff;
 753         struct flowi6 fl6;
 754         struct net *net = sk ? sock_net(sk) : dev_net(skb_dst(skb)->dev);
 755         struct sock *ctl_sk = net->ipv6.tcp_sk;
 756         unsigned int tot_len = sizeof(struct tcphdr);
 757         struct dst_entry *dst;
 758         __be32 *topt;
 759
 760         if (tsecr)
 761                 tot_len += TCPOLEN_TSTAMP_ALIGNED;
 762 #ifdef CONFIG_TCP_MD5SIG
 763         if (key)
 764                 tot_len += TCPOLEN_MD5SIG_ALIGNED;
 765 #endif
 766
 767         buff = alloc_skb(MAX_HEADER + sizeof(struct ipv6hdr) + tot_len,
 768                          GFP_ATOMIC);
 769         if (!buff)
 770                 return;
 771
 772         skb_reserve(buff, MAX_HEADER + sizeof(struct ipv6hdr) + tot_len);
 773
 774         t1 = (struct tcphdr *) skb_push(buff, tot_len);
 775         skb_reset_transport_header(buff);
 776
 777         /* Swap the send and the receive. */
 778         memset(t1, 0, sizeof(*t1));
 779         t1->dest = th->source;
 780         t1->source = th->dest;
 781         t1->doff = tot_len / 4;
 782         t1->seq = htonl(seq);
 783         t1->ack_seq = htonl(ack);
 784         t1->ack = !rst || !th->ack;
 785         t1->rst = rst;
 786         t1->window = htons(win);
 787
 788         topt = (__be32 *)(t1 + 1);
 789
 790         if (tsecr) {
 791                 *topt++ = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
 792                                 (TCPOPT_TIMESTAMP << 8) | TCPOLEN_TIMESTAMP);
 793                 *topt++ = htonl(tsval);
 794                 *topt++ = htonl(tsecr);
 795         }
 796
 797 #ifdef CONFIG_TCP_MD5SIG
 798         if (key) {
 799                 *topt++ = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
 800                                 (TCPOPT_MD5SIG << 8) | TCPOLEN_MD5SIG);
 801                 tcp_v6_md5_hash_hdr((__u8 *)topt, key,
 802                                     &ipv6_hdr(skb)->saddr,
 803                                     &ipv6_hdr(skb)->daddr, t1);
 804         }
 805 #endif
 806
 807         memset(&fl6, 0, sizeof(fl6));
 808         fl6.daddr = ipv6_hdr(skb)->saddr;
 809         fl6.saddr = ipv6_hdr(skb)->daddr;
 810         fl6.flowlabel = label;
 811
 812         buff->ip_summed = CHECKSUM_PARTIAL;
 813         buff->csum = 0;
 814
 815         __tcp_v6_send_check(buff, &fl6.saddr, &fl6.daddr);
 816
 817         fl6.flowi6_proto = IPPROTO_TCP;
 818         if (rt6_need_strict(&fl6.daddr) && !oif)
 819                 fl6.flowi6_oif = tcp_v6_iif(skb);
 820         else {
 821                 if (!oif && netif_index_is_l3_master(net, skb->skb_iif))
 822                         oif = skb->skb_iif;
 823
 824                 fl6.flowi6_oif = oif;
 825         }
 826
 827         fl6.flowi6_mark = IP6_REPLY_MARK(net, skb->mark);
 828         fl6.fl6_dport = t1->dest;
 829         fl6.fl6_sport = t1->source;
 830         security_skb_classify_flow(skb, flowi6_to_flowi(&fl6));
 831
 832         /* Pass a socket to ip6_dst_lookup either it is for RST
 833          * Underlying function will use this to retrieve the network
 834          * namespace
 835          */
 836         dst = ip6_dst_lookup_flow(ctl_sk, &fl6, NULL);
 837         if (!IS_ERR(dst)) {
 838                 skb_dst_set(buff, dst);
 839                 ip6_xmit(ctl_sk, buff, &fl6, NULL, tclass);
 840                 TCP_INC_STATS(net, TCP_MIB_OUTSEGS);
 841                 if (rst)
 842                         TCP_INC_STATS(net, TCP_MIB_OUTRSTS);
 843                 return;
 844         }
 845
 846         kfree_skb(buff);
 847 }
 848
 849 static void tcp_v6_send_reset(const struct sock *sk, struct sk_buff *skb)
 850 {
 851         const struct tcphdr *th = tcp_hdr(skb);
 852         u32 seq = 0, ack_seq = 0;
 853         struct tcp_md5sig_key *key = NULL;
 854 #ifdef CONFIG_TCP_MD5SIG
 855         const __u8 *hash_location = NULL;
 856         struct ipv6hdr *ipv6h = ipv6_hdr(skb);
 857         unsigned char newhash[16];
 858         int genhash;
 859         struct sock *sk1 = NULL;
 860 #endif
 861         int oif;
 862
 863         if (th->rst)
 864                 return;
 865
 866         /* If sk not NULL, it means we did a successful lookup and incoming
 867          * route had to be correct. prequeue might have dropped our dst.
 868          */
 869         if (!sk && !ipv6_unicast_destination(skb))
 870                 return;
 871
 872 #ifdef CONFIG_TCP_MD5SIG
 873         rcu_read_lock();
 874         hash_location = tcp_parse_md5sig_option(th);
 875         if (sk && sk_fullsock(sk)) {
 876                 key = tcp_v6_md5_do_lookup(sk, &ipv6h->saddr);
 877         } else if (hash_location) {
 878                 /*
 879                  * active side is lost. Try to find listening socket through
 880                  * source port, and then find md5 key through listening socket.
 881                  * we are not loose security here:
 882                  * Incoming packet is checked with md5 hash with finding key,
 883                  * no RST generated if md5 hash doesn't match.
 884                  */
 885                 sk1 = inet6_lookup_listener(dev_net(skb_dst(skb)->dev),
 886                                            &tcp_hashinfo, NULL, 0,
 887                                            &ipv6h->saddr,
 888                                            th->source, &ipv6h->daddr,
 889                                            ntohs(th->source), tcp_v6_iif(skb));
 890                 if (!sk1)
 891                         goto out;
 892
 893                 key = tcp_v6_md5_do_lookup(sk1, &ipv6h->saddr);
 894                 if (!key)
 895                         goto out;
 896
 897                 genhash = tcp_v6_md5_hash_skb(newhash, key, NULL, skb);
 898                 if (genhash || memcmp(hash_location, newhash, 16) != 0)
 899                         goto out;
 900         }
 901 #endif
 902
 903         if (th->ack)
 904                 seq = ntohl(th->ack_seq);
 905         else
 906                 ack_seq = ntohl(th->seq) + th->syn + th->fin + skb->len -
 907                           (th->doff << 2);
 908
 909         oif = sk ? sk->sk_bound_dev_if : 0;
 910         tcp_v6_send_response(sk, skb, seq, ack_seq, 0, 0, 0, oif, key, 1, 0, 0);
 911
 912 #ifdef CONFIG_TCP_MD5SIG
 913 out:
 914         rcu_read_unlock();
 915 #endif
 916 }
 917
 918 static void tcp_v6_send_ack(const struct sock *sk, struct sk_buff *skb, u32 seq,
 919                             u32 ack, u32 win, u32 tsval, u32 tsecr, int oif,
 920                             struct tcp_md5sig_key *key, u8 tclass,
 921                             __be32 label)
 922 {
 923         tcp_v6_send_response(sk, skb, seq, ack, win, tsval, tsecr, oif, key, 0,
 924                              tclass, label);
 925 }
 926
 927 static void tcp_v6_timewait_ack(struct sock *sk, struct sk_buff *skb)
 928 {
 929         struct inet_timewait_sock *tw = inet_twsk(sk);
 930         struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
 931
 932         tcp_v6_send_ack(sk, skb, tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
 933                         tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
 934                         tcp_time_stamp + tcptw->tw_ts_offset,
 935                         tcptw->tw_ts_recent, tw->tw_bound_dev_if, tcp_twsk_md5_key(tcptw),
 936                         tw->tw_tclass, cpu_to_be32(tw->tw_flowlabel));
 937
 938         inet_twsk_put(tw);
 939 }
 940
 941 static void tcp_v6_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb,
 942                                   struct request_sock *req)
 943 {
 944         /* sk->sk_state == TCP_LISTEN -> for regular TCP_SYN_RECV
 945          * sk->sk_state == TCP_SYN_RECV -> for Fast Open.
 946          */
 947         /* RFC 7323 2.3
 948          * The window field (SEG.WND) of every outgoing segment, with the
 949          * exception of <SYN> segments, MUST be right-shifted by
 950          * Rcv.Wind.Shift bits:
 951          */
 952         tcp_v6_send_ack(sk, skb, (sk->sk_state == TCP_LISTEN) ?
 953                         tcp_rsk(req)->snt_isn + 1 : tcp_sk(sk)->snd_nxt,
 954                         tcp_rsk(req)->rcv_nxt,
 955                         req->rsk_rcv_wnd >> inet_rsk(req)->rcv_wscale,
 956                         tcp_time_stamp, req->ts_recent, sk->sk_bound_dev_if,
 957                         tcp_v6_md5_do_lookup(sk, &ipv6_hdr(skb)->daddr),
 958                         0, 0);
 959 }
 960
 961
 962 static struct sock *tcp_v6_cookie_check(struct sock *sk, struct sk_buff *skb)
 963 {
 964 #ifdef CONFIG_SYN_COOKIES
 965         const struct tcphdr *th = tcp_hdr(skb);
 966
 967         if (!th->syn)
 968                 sk = cookie_v6_check(sk, skb);
 969 #endif
 970         return sk;
 971 }
 972
 973 static int tcp_v6_conn_request(struct sock *sk, struct sk_buff *skb)
 974 {
 975         if (skb->protocol == htons(ETH_P_IP))
 976                 return tcp_v4_conn_request(sk, skb);
 977
 978         if (!ipv6_unicast_destination(skb))
 979                 goto drop;
 980
 981         return tcp_conn_request(&tcp6_request_sock_ops,
 982                                 &tcp_request_sock_ipv6_ops, sk, skb);
 983
 984 drop:
 985         tcp_listendrop(sk);
 986         return 0; /* don't send reset */
 987 }
 988
 989 static struct sock *tcp_v6_syn_recv_sock(const struct sock *sk, struct sk_buff *skb,
 990                                          struct request_sock *req,
 991                                          struct dst_entry *dst,
 992                                          struct request_sock *req_unhash,
 993                                          bool *own_req)
 994 {
 995         struct inet_request_sock *ireq;
 996         struct ipv6_pinfo *newnp;
 997         const struct ipv6_pinfo *np = inet6_sk(sk);
 998         struct ipv6_txoptions *opt;
 999         struct tcp6_sock *newtcp6sk;
1000         struct inet_sock *newinet;
1001         struct tcp_sock *newtp;
1002         struct sock *newsk;
1003 #ifdef CONFIG_TCP_MD5SIG
1004         struct tcp_md5sig_key *key;
1005 #endif
1006         struct flowi6 fl6;
1007
1008         if (skb->protocol == htons(ETH_P_IP)) {
1009                 /*
1010                  *      v6 mapped
1011                  */
1012
1013                 newsk = tcp_v4_syn_recv_sock(sk, skb, req, dst,
1014                                              req_unhash, own_req);
1015
1016                 if (!newsk)
1017                         return NULL;
1018
1019                 newtcp6sk = (struct tcp6_sock *)newsk;
1020                 inet_sk(newsk)->pinet6 = &newtcp6sk->inet6;
1021
1022                 newinet = inet_sk(newsk);
1023                 newnp = inet6_sk(newsk);
1024                 newtp = tcp_sk(newsk);
1025
1026                 memcpy(newnp, np, sizeof(struct ipv6_pinfo));
1027
1028                 newnp->saddr = newsk->sk_v6_rcv_saddr;
1029
1030                 inet_csk(newsk)->icsk_af_ops = &ipv6_mapped;
1031                 newsk->sk_backlog_rcv = tcp_v4_do_rcv;
1032 #ifdef CONFIG_TCP_MD5SIG
1033                 newtp->af_specific = &tcp_sock_ipv6_mapped_specific;
1034 #endif
1035
1036                 newnp->ipv6_ac_list = NULL;
1037                 newnp->ipv6_fl_list = NULL;
1038                 newnp->pktoptions  = NULL;
1039                 newnp->opt         = NULL;
1040                 newnp->mcast_oif   = tcp_v6_iif(skb);
1041                 newnp->mcast_hops  = ipv6_hdr(skb)->hop_limit;
1042                 newnp->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(skb));
1043                 if (np->repflow)
1044                         newnp->flow_label = ip6_flowlabel(ipv6_hdr(skb));
1045
1046                 /*
1047                  * No need to charge this sock to the relevant IPv6 refcnt debug socks count
1048                  * here, tcp_create_openreq_child now does this for us, see the comment in
1049                  * that function for the gory details. -acme
1050                  */
1051
1052                 /* It is tricky place. Until this moment IPv4 tcp
1053                    worked with IPv6 icsk.icsk_af_ops.
1054                    Sync it now.
1055                  */
1056                 tcp_sync_mss(newsk, inet_csk(newsk)->icsk_pmtu_cookie);
1057
1058                 return newsk;
1059         }
1060
1061         ireq = inet_rsk(req);
1062
1063         if (sk_acceptq_is_full(sk))
1064                 goto out_overflow;
1065
1066         if (!dst) {
1067                 dst = inet6_csk_route_req(sk, &fl6, req, IPPROTO_TCP);
1068                 if (!dst)
1069                         goto out;
1070         }
1071
1072         newsk = tcp_create_openreq_child(sk, req, skb);
1073         if (!newsk)
1074                 goto out_nonewsk;
1075
1076         /*
1077          * No need to charge this sock to the relevant IPv6 refcnt debug socks
1078          * count here, tcp_create_openreq_child now does this for us, see the
1079          * comment in that function for the gory details. -acme
1080          */
1081
1082         newsk->sk_gso_type = SKB_GSO_TCPV6;
1083         ip6_dst_store(newsk, dst, NULL, NULL);
1084         inet6_sk_rx_dst_set(newsk, skb);
1085
1086         newtcp6sk = (struct tcp6_sock *)newsk;
1087         inet_sk(newsk)->pinet6 = &newtcp6sk->inet6;
1088
1089         newtp = tcp_sk(newsk);
1090         newinet = inet_sk(newsk);
1091         newnp = inet6_sk(newsk);
1092
1093         memcpy(newnp, np, sizeof(struct ipv6_pinfo));
1094
1095         newsk->sk_v6_daddr = ireq->ir_v6_rmt_addr;
1096         newnp->saddr = ireq->ir_v6_loc_addr;
1097         newsk->sk_v6_rcv_saddr = ireq->ir_v6_loc_addr;
1098         newsk->sk_bound_dev_if = ireq->ir_iif;
1099
1100         /* Now IPv6 options...
1101
1102            First: no IPv4 options.
1103          */
1104         newinet->inet_opt = NULL;
1105         newnp->ipv6_ac_list = NULL;
1106         newnp->ipv6_fl_list = NULL;
1107
1108         /* Clone RX bits */
1109         newnp->rxopt.all = np->rxopt.all;
1110
1111         newnp->pktoptions = NULL;
1112         newnp->opt        = NULL;
1113         newnp->mcast_oif  = tcp_v6_iif(skb);
1114         newnp->mcast_hops = ipv6_hdr(skb)->hop_limit;
1115         newnp->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(skb));
1116         if (np->repflow)
1117                 newnp->flow_label = ip6_flowlabel(ipv6_hdr(skb));
1118
1119         /* Clone native IPv6 options from listening socket (if any)
1120
1121            Yes, keeping reference count would be much more clever,
1122            but we make one more one thing there: reattach optmem
1123            to newsk.
1124          */
1125         opt = ireq->ipv6_opt;
1126         if (!opt)
1127                 opt = rcu_dereference(np->opt);
1128         if (opt) {
1129                 opt = ipv6_dup_options(newsk, opt);
1130                 RCU_INIT_POINTER(newnp->opt, opt);
1131         }
1132         inet_csk(newsk)->icsk_ext_hdr_len = 0;
1133         if (opt)
1134                 inet_csk(newsk)->icsk_ext_hdr_len = opt->opt_nflen +
1135                                                     opt->opt_flen;
1136
1137         tcp_ca_openreq_child(newsk, dst);
1138
1139         tcp_sync_mss(newsk, dst_mtu(dst));
1140         newtp->advmss = dst_metric_advmss(dst);
1141         if (tcp_sk(sk)->rx_opt.user_mss &&
1142             tcp_sk(sk)->rx_opt.user_mss < newtp->advmss)
1143                 newtp->advmss = tcp_sk(sk)->rx_opt.user_mss;
1144
1145         tcp_initialize_rcv_mss(newsk);
1146
1147         newinet->inet_daddr = newinet->inet_saddr = LOOPBACK4_IPV6;
1148         newinet->inet_rcv_saddr = LOOPBACK4_IPV6;
1149
1150 #ifdef CONFIG_TCP_MD5SIG
1151         /* Copy over the MD5 key from the original socket */
1152         key = tcp_v6_md5_do_lookup(sk, &newsk->sk_v6_daddr);
1153         if (key) {
1154                 /* We're using one, so create a matching key
1155                  * on the newsk structure. If we fail to get
1156                  * memory, then we end up not copying the key
1157                  * across. Shucks.
1158                  */
1159                 tcp_md5_do_add(newsk, (union tcp_md5_addr *)&newsk->sk_v6_daddr,
1160                                AF_INET6, key->key, key->keylen,
1161                                sk_gfp_mask(sk, GFP_ATOMIC));
1162         }
1163 #endif
1164
1165         if (__inet_inherit_port(sk, newsk) < 0) {
1166                 inet_csk_prepare_forced_close(newsk);
1167                 tcp_done(newsk);
1168                 goto out;
1169         }
1170         *own_req = inet_ehash_nolisten(newsk, req_to_sk(req_unhash));
1171         if (*own_req) {
1172                 tcp_move_syn(newtp, req);
1173
1174                 /* Clone pktoptions received with SYN, if we own the req */
1175                 if (ireq->pktopts) {
1176                         newnp->pktoptions = skb_clone(ireq->pktopts,
1177                                                       sk_gfp_mask(sk, GFP_ATOMIC));
1178                         consume_skb(ireq->pktopts);
1179                         ireq->pktopts = NULL;
1180                         if (newnp->pktoptions)
1181                                 skb_set_owner_r(newnp->pktoptions, newsk);
1182                 }
1183         }
1184
1185         return newsk;
1186
1187 out_overflow:
1188         __NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
1189 out_nonewsk:
1190         dst_release(dst);
1191 out:
1192         tcp_listendrop(sk);
1193         return NULL;
1194 }
1195
1196 /* The socket must have it's spinlock held when we get
1197  * here, unless it is a TCP_LISTEN socket.
1198  *
1199  * We have a potential double-lock case here, so even when
1200  * doing backlog processing we use the BH locking scheme.
1201  * This is because we cannot sleep with the original spinlock
1202  * held.
1203  */
1204 static int tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb)
1205 {
1206         struct ipv6_pinfo *np = inet6_sk(sk);
1207         struct tcp_sock *tp;
1208         struct sk_buff *opt_skb = NULL;
1209
1210         /* Imagine: socket is IPv6. IPv4 packet arrives,
1211            goes to IPv4 receive handler and backlogged.
1212            From backlog it always goes here. Kerboom...
1213            Fortunately, tcp_rcv_established and rcv_established
1214            handle them correctly, but it is not case with
1215            tcp_v6_hnd_req and tcp_v6_send_reset().   --ANK
1216          */
1217
1218         if (skb->protocol == htons(ETH_P_IP))
1219                 return tcp_v4_do_rcv(sk, skb);
1220
1221         if (sk_filter(sk, skb))
1222                 goto discard;
1223
1224         /*
1225          *      socket locking is here for SMP purposes as backlog rcv
1226          *      is currently called with bh processing disabled.
1227          */
1228
1229         /* Do Stevens' IPV6_PKTOPTIONS.
1230
1231            Yes, guys, it is the only place in our code, where we
1232            may make it not affecting IPv4.
1233            The rest of code is protocol independent,
1234            and I do not like idea to uglify IPv4.
1235
1236            Actually, all the idea behind IPV6_PKTOPTIONS
1237            looks not very well thought. For now we latch
1238            options, received in the last packet, enqueued
1239            by tcp. Feel free to propose better solution.
1240                                                --ANK (980728)
1241          */
1242         if (np->rxopt.all)
1243                 opt_skb = skb_clone(skb, sk_gfp_mask(sk, GFP_ATOMIC));
1244
1245         if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
1246                 struct dst_entry *dst = sk->sk_rx_dst;
1247
1248                 sock_rps_save_rxhash(sk, skb);
1249                 sk_mark_napi_id(sk, skb);
1250                 if (dst) {
1251                         if (inet_sk(sk)->rx_dst_ifindex != skb->skb_iif ||
1252                             dst->ops->check(dst, np->rx_dst_cookie) == NULL) {
1253                                 dst_release(dst);
1254                                 sk->sk_rx_dst = NULL;
1255                         }
1256                 }
1257
1258                 tcp_rcv_established(sk, skb, tcp_hdr(skb), skb->len);
1259                 if (opt_skb)
1260                         goto ipv6_pktoptions;
1261                 return 0;
1262         }
1263
1264         if (tcp_checksum_complete(skb))
1265                 goto csum_err;
1266
1267         if (sk->sk_state == TCP_LISTEN) {
1268                 struct sock *nsk = tcp_v6_cookie_check(sk, skb);
1269
1270                 if (!nsk)
1271                         goto discard;
1272
1273                 if (nsk != sk) {
1274                         sock_rps_save_rxhash(nsk, skb);
1275                         sk_mark_napi_id(nsk, skb);
1276                         if (tcp_child_process(sk, nsk, skb))
1277                                 goto reset;
1278                         if (opt_skb)
1279                                 __kfree_skb(opt_skb);
1280                         return 0;
1281                 }
1282         } else
1283                 sock_rps_save_rxhash(sk, skb);
1284
1285         if (tcp_rcv_state_process(sk, skb))
1286                 goto reset;
1287         if (opt_skb)
1288                 goto ipv6_pktoptions;
1289         return 0;
1290
1291 reset:
1292         tcp_v6_send_reset(sk, skb);
1293 discard:
1294         if (opt_skb)
1295                 __kfree_skb(opt_skb);
1296         kfree_skb(skb);
1297         return 0;
1298 csum_err:
1299         TCP_INC_STATS(sock_net(sk), TCP_MIB_CSUMERRORS);
1300         TCP_INC_STATS(sock_net(sk), TCP_MIB_INERRS);
1301         goto discard;
1302
1303
1304 ipv6_pktoptions:
1305         /* Do you ask, what is it?
1306
1307            1. skb was enqueued by tcp.
1308            2. skb is added to tail of read queue, rather than out of order.
1309            3. socket is not in passive state.
1310            4. Finally, it really contains options, which user wants to receive.
1311          */
1312         tp = tcp_sk(sk);
1313         if (TCP_SKB_CB(opt_skb)->end_seq == tp->rcv_nxt &&
1314             !((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN))) {
1315                 if (np->rxopt.bits.rxinfo || np->rxopt.bits.rxoinfo)
1316                         np->mcast_oif = tcp_v6_iif(opt_skb);
1317                 if (np->rxopt.bits.rxhlim || np->rxopt.bits.rxohlim)
1318                         np->mcast_hops = ipv6_hdr(opt_skb)->hop_limit;
1319                 if (np->rxopt.bits.rxflow || np->rxopt.bits.rxtclass)
1320                         np->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(opt_skb));
1321                 if (np->repflow)
1322                         np->flow_label = ip6_flowlabel(ipv6_hdr(opt_skb));
1323                 if (ipv6_opt_accepted(sk, opt_skb, &TCP_SKB_CB(opt_skb)->header.h6)) {
1324                         skb_set_owner_r(opt_skb, sk);
1325                         opt_skb = xchg(&np->pktoptions, opt_skb);
1326                 } else {
1327                         __kfree_skb(opt_skb);
1328                         opt_skb = xchg(&np->pktoptions, NULL);
1329                 }
1330         }
1331
1332         kfree_skb(opt_skb);
1333         return 0;
1334 }
1335
1336 static void tcp_v6_fill_cb(struct sk_buff *skb, const struct ipv6hdr *hdr,
1337                            const struct tcphdr *th)
1338 {
1339         /* This is tricky: we move IP6CB at its correct location into
1340          * TCP_SKB_CB(). It must be done after xfrm6_policy_check(), because
1341          * _decode_session6() uses IP6CB().
1342          * barrier() makes sure compiler won't play aliasing games.
1343          */
1344         memmove(&TCP_SKB_CB(skb)->header.h6, IP6CB(skb),
1345                 sizeof(struct inet6_skb_parm));
1346         barrier();
1347
1348         TCP_SKB_CB(skb)->seq = ntohl(th->seq);
1349         TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
1350                                     skb->len - th->doff*4);
1351         TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
1352         TCP_SKB_CB(skb)->tcp_flags = tcp_flag_byte(th);
1353         TCP_SKB_CB(skb)->tcp_tw_isn = 0;
1354         TCP_SKB_CB(skb)->ip_dsfield = ipv6_get_dsfield(hdr);
1355         TCP_SKB_CB(skb)->sacked = 0;
1356 }
1357
1358 static void tcp_v6_restore_cb(struct sk_buff *skb)
1359 {
1360         /* We need to move header back to the beginning if xfrm6_policy_check()
1361          * and tcp_v6_fill_cb() are going to be called again.
1362          */
1363         memmove(IP6CB(skb), &TCP_SKB_CB(skb)->header.h6,
1364                 sizeof(struct inet6_skb_parm));
1365 }
1366
1367 static int tcp_v6_rcv(struct sk_buff *skb)
1368 {
1369         const struct tcphdr *th;
1370         const struct ipv6hdr *hdr;
1371         bool refcounted;
1372         struct sock *sk;
1373         int ret;
1374         struct net *net = dev_net(skb->dev);
1375
1376         if (skb->pkt_type != PACKET_HOST)
1377                 goto discard_it;
1378
1379         /*
1380          *      Count it even if it's bad.
1381          */
1382         __TCP_INC_STATS(net, TCP_MIB_INSEGS);
1383
1384         if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
1385                 goto discard_it;
1386
1387         th = (const struct tcphdr *)skb->data;
1388
1389         if (unlikely(th->doff < sizeof(struct tcphdr)/4))
1390                 goto bad_packet;
1391         if (!pskb_may_pull(skb, th->doff*4))
1392                 goto discard_it;
1393
1394         if (skb_checksum_init(skb, IPPROTO_TCP, ip6_compute_pseudo))
1395                 goto csum_error;
1396
1397         th = (const struct tcphdr *)skb->data;
1398         hdr = ipv6_hdr(skb);
1399
1400 lookup:
1401         sk = __inet6_lookup_skb(&tcp_hashinfo, skb, __tcp_hdrlen(th),
1402                                 th->source, th->dest, inet6_iif(skb),
1403                                 &refcounted);
1404         if (!sk)
1405                 goto no_tcp_socket;
1406
1407 process:
1408         if (sk->sk_state == TCP_TIME_WAIT)
1409                 goto do_time_wait;
1410
1411         if (sk->sk_state == TCP_NEW_SYN_RECV) {
1412                 struct request_sock *req = inet_reqsk(sk);
1413                 struct sock *nsk;
1414
1415                 sk = req->rsk_listener;
1416                 tcp_v6_fill_cb(skb, hdr, th);
1417                 if (tcp_v6_inbound_md5_hash(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 (unlikely(sk_add_backlog(sk, skb,
1475                                            sk->sk_rcvbuf + sk->sk_sndbuf))) {
1476                 bh_unlock_sock(sk);
1477                 __NET_INC_STATS(net, LINUX_MIB_TCPBACKLOGDROP);
1478                 goto discard_and_relse;
1479         }
1480         bh_unlock_sock(sk);
1481
1482 put_and_return:
1483         if (refcounted)
1484                 sock_put(sk);
1485         return ret ? -1 : 0;
1486
1487 no_tcp_socket:
1488         if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb))
1489                 goto discard_it;
1490
1491         tcp_v6_fill_cb(skb, hdr, th);
1492
1493         if (tcp_checksum_complete(skb)) {
1494 csum_error:
1495                 __TCP_INC_STATS(net, TCP_MIB_CSUMERRORS);
1496 bad_packet:
1497                 __TCP_INC_STATS(net, TCP_MIB_INERRS);
1498         } else {
1499                 tcp_v6_send_reset(NULL, skb);
1500         }
1501
1502 discard_it:
1503         kfree_skb(skb);
1504         return 0;
1505
1506 discard_and_relse:
1507         sk_drops_add(sk, skb);
1508         if (refcounted)
1509                 sock_put(sk);
1510         goto discard_it;
1511
1512 do_time_wait:
1513         if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
1514                 inet_twsk_put(inet_twsk(sk));
1515                 goto discard_it;
1516         }
1517
1518         tcp_v6_fill_cb(skb, hdr, th);
1519
1520         if (tcp_checksum_complete(skb)) {
1521                 inet_twsk_put(inet_twsk(sk));
1522                 goto csum_error;
1523         }
1524
1525         switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) {
1526         case TCP_TW_SYN:
1527         {
1528                 struct sock *sk2;
1529
1530                 sk2 = inet6_lookup_listener(dev_net(skb->dev), &tcp_hashinfo,
1531                                             skb, __tcp_hdrlen(th),
1532                                             &ipv6_hdr(skb)->saddr, th->source,
1533                                             &ipv6_hdr(skb)->daddr,
1534                                             ntohs(th->dest), tcp_v6_iif(skb));
1535                 if (sk2) {
1536                         struct inet_timewait_sock *tw = inet_twsk(sk);
1537                         inet_twsk_deschedule_put(tw);
1538                         sk = sk2;
1539                         tcp_v6_restore_cb(skb);
1540                         refcounted = false;
1541                         goto process;
1542                 }
1543                 /* Fall through to ACK */
1544         }
1545         case TCP_TW_ACK:
1546                 tcp_v6_timewait_ack(sk, skb);
1547                 break;
1548         case TCP_TW_RST:
1549                 tcp_v6_restore_cb(skb);
1550                 tcp_v6_send_reset(sk, skb);
1551                 inet_twsk_deschedule_put(inet_twsk(sk));
1552                 goto discard_it;
1553         case TCP_TW_SUCCESS:
1554                 ;
1555         }
1556         goto discard_it;
1557 }
1558
1559 static void tcp_v6_early_demux(struct sk_buff *skb)
1560 {
1561         const struct ipv6hdr *hdr;
1562         const struct tcphdr *th;
1563         struct sock *sk;
1564
1565         if (skb->pkt_type != PACKET_HOST)
1566                 return;
1567
1568         if (!pskb_may_pull(skb, skb_transport_offset(skb) + sizeof(struct tcphdr)))
1569                 return;
1570
1571         hdr = ipv6_hdr(skb);
1572         th = tcp_hdr(skb);
1573
1574         if (th->doff < sizeof(struct tcphdr) / 4)
1575                 return;
1576
1577         /* Note : We use inet6_iif() here, not tcp_v6_iif() */
1578         sk = __inet6_lookup_established(dev_net(skb->dev), &tcp_hashinfo,
1579                                         &hdr->saddr, th->source,
1580                                         &hdr->daddr, ntohs(th->dest),
1581                                         inet6_iif(skb));
1582         if (sk) {
1583                 skb->sk = sk;
1584                 skb->destructor = sock_edemux;
1585                 if (sk_fullsock(sk)) {
1586                         struct dst_entry *dst = READ_ONCE(sk->sk_rx_dst);
1587
1588                         if (dst)
1589                                 dst = dst_check(dst, inet6_sk(sk)->rx_dst_cookie);
1590                         if (dst &&
1591                             inet_sk(sk)->rx_dst_ifindex == skb->skb_iif)
1592                                 skb_dst_set_noref(skb, dst);
1593                 }
1594         }
1595 }
1596
1597 static struct timewait_sock_ops tcp6_timewait_sock_ops = {
1598         .twsk_obj_size  = sizeof(struct tcp6_timewait_sock),
1599         .twsk_unique    = tcp_twsk_unique,
1600         .twsk_destructor = tcp_twsk_destructor,
1601 };
1602
1603 static const struct inet_connection_sock_af_ops ipv6_specific = {
1604         .queue_xmit        = inet6_csk_xmit,
1605         .send_check        = tcp_v6_send_check,
1606         .rebuild_header    = inet6_sk_rebuild_header,
1607         .sk_rx_dst_set     = inet6_sk_rx_dst_set,
1608         .conn_request      = tcp_v6_conn_request,
1609         .syn_recv_sock     = tcp_v6_syn_recv_sock,
1610         .net_header_len    = sizeof(struct ipv6hdr),
1611         .net_frag_header_len = sizeof(struct frag_hdr),
1612         .setsockopt        = ipv6_setsockopt,
1613         .getsockopt        = ipv6_getsockopt,
1614         .addr2sockaddr     = inet6_csk_addr2sockaddr,
1615         .sockaddr_len      = sizeof(struct sockaddr_in6),
1616         .bind_conflict     = inet6_csk_bind_conflict,
1617 #ifdef CONFIG_COMPAT
1618         .compat_setsockopt = compat_ipv6_setsockopt,
1619         .compat_getsockopt = compat_ipv6_getsockopt,
1620 #endif
1621         .mtu_reduced       = tcp_v6_mtu_reduced,
1622 };
1623
1624 #ifdef CONFIG_TCP_MD5SIG
1625 static const struct tcp_sock_af_ops tcp_sock_ipv6_specific = {
1626         .md5_lookup     =       tcp_v6_md5_lookup,
1627         .calc_md5_hash  =       tcp_v6_md5_hash_skb,
1628         .md5_parse      =       tcp_v6_parse_md5_keys,
1629 };
1630 #endif
1631
1632 /*
1633  *      TCP over IPv4 via INET6 API
1634  */
1635 static const struct inet_connection_sock_af_ops ipv6_mapped = {
1636         .queue_xmit        = ip_queue_xmit,
1637         .send_check        = tcp_v4_send_check,
1638         .rebuild_header    = inet_sk_rebuild_header,
1639         .sk_rx_dst_set     = inet_sk_rx_dst_set,
1640         .conn_request      = tcp_v6_conn_request,
1641         .syn_recv_sock     = tcp_v6_syn_recv_sock,
1642         .net_header_len    = sizeof(struct iphdr),
1643         .setsockopt        = ipv6_setsockopt,
1644         .getsockopt        = ipv6_getsockopt,
1645         .addr2sockaddr     = inet6_csk_addr2sockaddr,
1646         .sockaddr_len      = sizeof(struct sockaddr_in6),
1647         .bind_conflict     = inet6_csk_bind_conflict,
1648 #ifdef CONFIG_COMPAT
1649         .compat_setsockopt = compat_ipv6_setsockopt,
1650         .compat_getsockopt = compat_ipv6_getsockopt,
1651 #endif
1652         .mtu_reduced       = tcp_v4_mtu_reduced,
1653 };
1654
1655 #ifdef CONFIG_TCP_MD5SIG
1656 static const struct tcp_sock_af_ops tcp_sock_ipv6_mapped_specific = {
1657         .md5_lookup     =       tcp_v4_md5_lookup,
1658         .calc_md5_hash  =       tcp_v4_md5_hash_skb,
1659         .md5_parse      =       tcp_v6_parse_md5_keys,
1660 };
1661 #endif
1662
1663 /* NOTE: A lot of things set to zero explicitly by call to
1664  *       sk_alloc() so need not be done here.
1665  */
1666 static int tcp_v6_init_sock(struct sock *sk)
1667 {
1668         struct inet_connection_sock *icsk = inet_csk(sk);
1669
1670         tcp_init_sock(sk);
1671
1672         icsk->icsk_af_ops = &ipv6_specific;
1673
1674 #ifdef CONFIG_TCP_MD5SIG
1675         tcp_sk(sk)->af_specific = &tcp_sock_ipv6_specific;
1676 #endif
1677
1678         return 0;
1679 }
1680
1681 static void tcp_v6_destroy_sock(struct sock *sk)
1682 {
1683         tcp_v4_destroy_sock(sk);
1684         inet6_destroy_sock(sk);
1685 }
1686
1687 #ifdef CONFIG_PROC_FS
1688 /* Proc filesystem TCPv6 sock list dumping. */
1689 static void get_openreq6(struct seq_file *seq,
1690                          const struct request_sock *req, int i)
1691 {
1692         long ttd = req->rsk_timer.expires - jiffies;
1693         const struct in6_addr *src = &inet_rsk(req)->ir_v6_loc_addr;
1694         const struct in6_addr *dest = &inet_rsk(req)->ir_v6_rmt_addr;
1695
1696         if (ttd < 0)
1697                 ttd = 0;
1698
1699         seq_printf(seq,
1700                    "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
1701                    "%02X %08X:%08X %02X:%08lX %08X %5u %8d %d %d %pK\n",
1702                    i,
1703                    src->s6_addr32[0], src->s6_addr32[1],
1704                    src->s6_addr32[2], src->s6_addr32[3],
1705                    inet_rsk(req)->ir_num,
1706                    dest->s6_addr32[0], dest->s6_addr32[1],
1707                    dest->s6_addr32[2], dest->s6_addr32[3],
1708                    ntohs(inet_rsk(req)->ir_rmt_port),
1709                    TCP_SYN_RECV,
1710                    0, 0, /* could print option size, but that is af dependent. */
1711                    1,   /* timers active (only the expire timer) */
1712                    jiffies_to_clock_t(ttd),
1713                    req->num_timeout,
1714                    from_kuid_munged(seq_user_ns(seq),
1715                                     sock_i_uid(req->rsk_listener)),
1716                    0,  /* non standard timer */
1717                    0, /* open_requests have no inode */
1718                    0, req);
1719 }
1720
1721 static void get_tcp6_sock(struct seq_file *seq, struct sock *sp, int i)
1722 {
1723         const struct in6_addr *dest, *src;
1724         __u16 destp, srcp;
1725         int timer_active;
1726         unsigned long timer_expires;
1727         const struct inet_sock *inet = inet_sk(sp);
1728         const struct tcp_sock *tp = tcp_sk(sp);
1729         const struct inet_connection_sock *icsk = inet_csk(sp);
1730         const struct fastopen_queue *fastopenq = &icsk->icsk_accept_queue.fastopenq;
1731         int rx_queue;
1732         int state;
1733
1734         dest  = &sp->sk_v6_daddr;
1735         src   = &sp->sk_v6_rcv_saddr;
1736         destp = ntohs(inet->inet_dport);
1737         srcp  = ntohs(inet->inet_sport);
1738
1739         if (icsk->icsk_pending == ICSK_TIME_RETRANS ||
1740             icsk->icsk_pending == ICSK_TIME_EARLY_RETRANS ||
1741             icsk->icsk_pending == ICSK_TIME_LOSS_PROBE) {
1742                 timer_active    = 1;
1743                 timer_expires   = icsk->icsk_timeout;
1744         } else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
1745                 timer_active    = 4;
1746                 timer_expires   = icsk->icsk_timeout;
1747         } else if (timer_pending(&sp->sk_timer)) {
1748                 timer_active    = 2;
1749                 timer_expires   = sp->sk_timer.expires;
1750         } else {
1751                 timer_active    = 0;
1752                 timer_expires = jiffies;
1753         }
1754
1755         state = sk_state_load(sp);
1756         if (state == TCP_LISTEN)
1757                 rx_queue = sp->sk_ack_backlog;
1758         else
1759                 /* Because we don't lock the socket,
1760                  * we might find a transient negative value.
1761                  */
1762                 rx_queue = max_t(int, tp->rcv_nxt - tp->copied_seq, 0);
1763
1764         seq_printf(seq,
1765                    "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
1766                    "%02X %08X:%08X %02X:%08lX %08X %5u %8d %lu %d %pK %lu %lu %u %u %d\n",
1767                    i,
1768                    src->s6_addr32[0], src->s6_addr32[1],
1769                    src->s6_addr32[2], src->s6_addr32[3], srcp,
1770                    dest->s6_addr32[0], dest->s6_addr32[1],
1771                    dest->s6_addr32[2], dest->s6_addr32[3], destp,
1772                    state,
1773                    tp->write_seq - tp->snd_una,
1774                    rx_queue,
1775                    timer_active,
1776                    jiffies_delta_to_clock_t(timer_expires - jiffies),
1777                    icsk->icsk_retransmits,
1778                    from_kuid_munged(seq_user_ns(seq), sock_i_uid(sp)),
1779                    icsk->icsk_probes_out,
1780                    sock_i_ino(sp),
1781                    atomic_read(&sp->sk_refcnt), sp,
1782                    jiffies_to_clock_t(icsk->icsk_rto),
1783                    jiffies_to_clock_t(icsk->icsk_ack.ato),
1784                    (icsk->icsk_ack.quick << 1) | icsk->icsk_ack.pingpong,
1785                    tp->snd_cwnd,
1786                    state == TCP_LISTEN ?
1787                         fastopenq->max_qlen :
1788                         (tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh)
1789                    );
1790 }
1791
1792 static void get_timewait6_sock(struct seq_file *seq,
1793                                struct inet_timewait_sock *tw, int i)
1794 {
1795         long delta = tw->tw_timer.expires - jiffies;
1796         const struct in6_addr *dest, *src;
1797         __u16 destp, srcp;
1798
1799         dest = &tw->tw_v6_daddr;
1800         src  = &tw->tw_v6_rcv_saddr;
1801         destp = ntohs(tw->tw_dport);
1802         srcp  = ntohs(tw->tw_sport);
1803
1804         seq_printf(seq,
1805                    "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
1806                    "%02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK\n",
1807                    i,
1808                    src->s6_addr32[0], src->s6_addr32[1],
1809                    src->s6_addr32[2], src->s6_addr32[3], srcp,
1810                    dest->s6_addr32[0], dest->s6_addr32[1],
1811                    dest->s6_addr32[2], dest->s6_addr32[3], destp,
1812                    tw->tw_substate, 0, 0,
1813                    3, jiffies_delta_to_clock_t(delta), 0, 0, 0, 0,
1814                    atomic_read(&tw->tw_refcnt), tw);
1815 }
1816
1817 static int tcp6_seq_show(struct seq_file *seq, void *v)
1818 {
1819         struct tcp_iter_state *st;
1820         struct sock *sk = v;
1821
1822         if (v == SEQ_START_TOKEN) {
1823                 seq_puts(seq,
1824                          "  sl  "
1825                          "local_address                         "
1826                          "remote_address                        "
1827                          "st tx_queue rx_queue tr tm->when retrnsmt"
1828                          "   uid  timeout inode\n");
1829                 goto out;
1830         }
1831         st = seq->private;
1832
1833         if (sk->sk_state == TCP_TIME_WAIT)
1834                 get_timewait6_sock(seq, v, st->num);
1835         else if (sk->sk_state == TCP_NEW_SYN_RECV)
1836                 get_openreq6(seq, v, st->num);
1837         else
1838                 get_tcp6_sock(seq, v, st->num);
1839 out:
1840         return 0;
1841 }
1842
1843 static const struct file_operations tcp6_afinfo_seq_fops = {
1844         .owner   = THIS_MODULE,
1845         .open    = tcp_seq_open,
1846         .read    = seq_read,
1847         .llseek  = seq_lseek,
1848         .release = seq_release_net
1849 };
1850
1851 static struct tcp_seq_afinfo tcp6_seq_afinfo = {
1852         .name           = "tcp6",
1853         .family         = AF_INET6,
1854         .seq_fops       = &tcp6_afinfo_seq_fops,
1855         .seq_ops        = {
1856                 .show           = tcp6_seq_show,
1857         },
1858 };
1859
1860 int __net_init tcp6_proc_init(struct net *net)
1861 {
1862         return tcp_proc_register(net, &tcp6_seq_afinfo);
1863 }
1864
1865 void tcp6_proc_exit(struct net *net)
1866 {
1867         tcp_proc_unregister(net, &tcp6_seq_afinfo);
1868 }
1869 #endif
1870
1871 static void tcp_v6_clear_sk(struct sock *sk, int size)
1872 {
1873         struct inet_sock *inet = inet_sk(sk);
1874
1875         /* we do not want to clear pinet6 field, because of RCU lookups */
1876         sk_prot_clear_nulls(sk, offsetof(struct inet_sock, pinet6));
1877
1878         size -= offsetof(struct inet_sock, pinet6) + sizeof(inet->pinet6);
1879         memset(&inet->pinet6 + 1, 0, size);
1880 }
1881
1882 struct proto tcpv6_prot = {
1883         .name                   = "TCPv6",
1884         .owner                  = THIS_MODULE,
1885         .close                  = tcp_close,
1886         .connect                = tcp_v6_connect,
1887         .disconnect             = tcp_disconnect,
1888         .accept                 = inet_csk_accept,
1889         .ioctl                  = tcp_ioctl,
1890         .init                   = tcp_v6_init_sock,
1891         .destroy                = tcp_v6_destroy_sock,
1892         .shutdown               = tcp_shutdown,
1893         .setsockopt             = tcp_setsockopt,
1894         .getsockopt             = tcp_getsockopt,
1895         .recvmsg                = tcp_recvmsg,
1896         .sendmsg                = tcp_sendmsg,
1897         .sendpage               = tcp_sendpage,
1898         .backlog_rcv            = tcp_v6_do_rcv,
1899         .release_cb             = tcp_release_cb,
1900         .hash                   = inet6_hash,
1901         .unhash                 = inet_unhash,
1902         .get_port               = inet_csk_get_port,
1903         .enter_memory_pressure  = tcp_enter_memory_pressure,
1904         .stream_memory_free     = tcp_stream_memory_free,
1905         .sockets_allocated      = &tcp_sockets_allocated,
1906         .memory_allocated       = &tcp_memory_allocated,
1907         .memory_pressure        = &tcp_memory_pressure,
1908         .orphan_count           = &tcp_orphan_count,
1909         .sysctl_mem             = sysctl_tcp_mem,
1910         .sysctl_wmem            = sysctl_tcp_wmem,
1911         .sysctl_rmem            = sysctl_tcp_rmem,
1912         .max_header             = MAX_TCP_HEADER,
1913         .obj_size               = sizeof(struct tcp6_sock),
1914         .slab_flags             = SLAB_DESTROY_BY_RCU,
1915         .twsk_prot              = &tcp6_timewait_sock_ops,
1916         .rsk_prot               = &tcp6_request_sock_ops,
1917         .h.hashinfo             = &tcp_hashinfo,
1918         .no_autobind            = true,
1919 #ifdef CONFIG_COMPAT
1920         .compat_setsockopt      = compat_tcp_setsockopt,
1921         .compat_getsockopt      = compat_tcp_getsockopt,
1922 #endif
1923         .clear_sk               = tcp_v6_clear_sk,
1924         .diag_destroy           = tcp_abort,
1925 };
1926
1927 static const struct inet6_protocol tcpv6_protocol = {
1928         .early_demux    =       tcp_v6_early_demux,
1929         .handler        =       tcp_v6_rcv,
1930         .err_handler    =       tcp_v6_err,
1931         .flags          =       INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
1932 };
1933
1934 static struct inet_protosw tcpv6_protosw = {
1935         .type           =       SOCK_STREAM,
1936         .protocol       =       IPPROTO_TCP,
1937         .prot           =       &tcpv6_prot,
1938         .ops            =       &inet6_stream_ops,
1939         .flags          =       INET_PROTOSW_PERMANENT |
1940                                 INET_PROTOSW_ICSK,
1941 };
1942
1943 static int __net_init tcpv6_net_init(struct net *net)
1944 {
1945         return inet_ctl_sock_create(&net->ipv6.tcp_sk, PF_INET6,
1946                                     SOCK_RAW, IPPROTO_TCP, net);
1947 }
1948
1949 static void __net_exit tcpv6_net_exit(struct net *net)
1950 {
1951         inet_ctl_sock_destroy(net->ipv6.tcp_sk);
1952 }
1953
1954 static void __net_exit tcpv6_net_exit_batch(struct list_head *net_exit_list)
1955 {
1956         inet_twsk_purge(&tcp_hashinfo, &tcp_death_row, AF_INET6);
1957 }
1958
1959 static struct pernet_operations tcpv6_net_ops = {
1960         .init       = tcpv6_net_init,
1961         .exit       = tcpv6_net_exit,
1962         .exit_batch = tcpv6_net_exit_batch,
1963 };
1964
1965 int __init tcpv6_init(void)
1966 {
1967         int ret;
1968
1969         ret = inet6_add_protocol(&tcpv6_protocol, IPPROTO_TCP);
1970         if (ret)
1971                 goto out;
1972
1973         /* register inet6 protocol */
1974         ret = inet6_register_protosw(&tcpv6_protosw);
1975         if (ret)
1976                 goto out_tcpv6_protocol;
1977
1978         ret = register_pernet_subsys(&tcpv6_net_ops);
1979         if (ret)
1980                 goto out_tcpv6_protosw;
1981 out:
1982         return ret;
1983
1984 out_tcpv6_protosw:
1985         inet6_unregister_protosw(&tcpv6_protosw);
1986 out_tcpv6_protocol:
1987         inet6_del_protocol(&tcpv6_protocol, IPPROTO_TCP);
1988         goto out;
1989 }
1990
1991 void tcpv6_exit(void)
1992 {
1993         unregister_pernet_subsys(&tcpv6_net_ops);
1994         inet6_unregister_protosw(&tcpv6_protosw);
1995         inet6_del_protocol(&tcpv6_protocol, IPPROTO_TCP);
1996 }