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/tcp_memcontrol.h>
  65 #include <net/busy_poll.h>
  66
  67 #include <linux/proc_fs.h>
  68 #include <linux/seq_file.h>
  69
  70 #include <linux/crypto.h>
  71 #include <linux/scatterlist.h>
  72
  73 static void     tcp_v6_send_reset(const struct sock *sk, struct sk_buff *skb);
  74 static void     tcp_v6_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb,
  75                                       struct request_sock *req);
  76
  77 static int      tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb);
  78
  79 static const struct inet_connection_sock_af_ops ipv6_mapped;
  80 static const struct inet_connection_sock_af_ops ipv6_specific;
  81 #ifdef CONFIG_TCP_MD5SIG
  82 static const struct tcp_sock_af_ops tcp_sock_ipv6_specific;
  83 static const struct tcp_sock_af_ops tcp_sock_ipv6_mapped_specific;
  84 #else
  85 static struct tcp_md5sig_key *tcp_v6_md5_do_lookup(const struct sock *sk,
  86                                                    const struct in6_addr *addr)
  87 {
  88         return NULL;
  89 }
  90 #endif
  91
  92 static void inet6_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb)
  93 {
  94         struct dst_entry *dst = skb_dst(skb);
  95
  96         if (dst && dst_hold_safe(dst)) {
  97                 const struct rt6_info *rt = (const struct rt6_info *)dst;
  98
  99                 sk->sk_rx_dst = dst;
 100                 inet_sk(sk)->rx_dst_ifindex = skb->skb_iif;
 101                 inet6_sk(sk)->rx_dst_cookie = rt6_get_cookie(rt);
 102         }
 103 }
 104
 105 static __u32 tcp_v6_init_sequence(const struct sk_buff *skb)
 106 {
 107         return secure_tcpv6_sequence_number(ipv6_hdr(skb)->daddr.s6_addr32,
 108                                             ipv6_hdr(skb)->saddr.s6_addr32,
 109                                             tcp_hdr(skb)->dest,
 110                                             tcp_hdr(skb)->source);
 111 }
 112
 113 static int tcp_v6_connect(struct sock *sk, struct sockaddr *uaddr,
 114                           int addr_len)
 115 {
 116         struct sockaddr_in6 *usin = (struct sockaddr_in6 *) uaddr;
 117         struct inet_sock *inet = inet_sk(sk);
 118         struct inet_connection_sock *icsk = inet_csk(sk);
 119         struct ipv6_pinfo *np = inet6_sk(sk);
 120         struct tcp_sock *tp = tcp_sk(sk);
 121         struct in6_addr *saddr = NULL, *final_p, final;
 122         struct ipv6_txoptions *opt;
 123         struct flowi6 fl6;
 124         struct dst_entry *dst;
 125         int addr_type;
 126         int err;
 127
 128         if (addr_len < SIN6_LEN_RFC2133)
 129                 return -EINVAL;
 130
 131         if (usin->sin6_family != AF_INET6)
 132                 return -EAFNOSUPPORT;
 133
 134         memset(&fl6, 0, sizeof(fl6));
 135
 136         if (np->sndflow) {
 137                 fl6.flowlabel = usin->sin6_flowinfo&IPV6_FLOWINFO_MASK;
 138                 IP6_ECN_flow_init(fl6.flowlabel);
 139                 if (fl6.flowlabel&IPV6_FLOWLABEL_MASK) {
 140                         struct ip6_flowlabel *flowlabel;
 141                         flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
 142                         if (!flowlabel)
 143                                 return -EINVAL;
 144                         fl6_sock_release(flowlabel);
 145                 }
 146         }
 147
 148         /*
 149          *      connect() to INADDR_ANY means loopback (BSD'ism).
 150          */
 151
 152         if (ipv6_addr_any(&usin->sin6_addr))
 153                 usin->sin6_addr.s6_addr[15] = 0x1;
 154
 155         addr_type = ipv6_addr_type(&usin->sin6_addr);
 156
 157         if (addr_type & IPV6_ADDR_MULTICAST)
 158                 return -ENETUNREACH;
 159
 160         if (addr_type&IPV6_ADDR_LINKLOCAL) {
 161                 if (addr_len >= sizeof(struct sockaddr_in6) &&
 162                     usin->sin6_scope_id) {
 163                         /* If interface is set while binding, indices
 164                          * must coincide.
 165                          */
 166                         if (sk->sk_bound_dev_if &&
 167                             sk->sk_bound_dev_if != usin->sin6_scope_id)
 168                                 return -EINVAL;
 169
 170                         sk->sk_bound_dev_if = usin->sin6_scope_id;
 171                 }
 172
 173                 /* Connect to link-local address requires an interface */
 174                 if (!sk->sk_bound_dev_if)
 175                         return -EINVAL;
 176         }
 177
 178         if (tp->rx_opt.ts_recent_stamp &&
 179             !ipv6_addr_equal(&sk->sk_v6_daddr, &usin->sin6_addr)) {
 180                 tp->rx_opt.ts_recent = 0;
 181                 tp->rx_opt.ts_recent_stamp = 0;
 182                 tp->write_seq = 0;
 183         }
 184
 185         sk->sk_v6_daddr = usin->sin6_addr;
 186         np->flow_label = fl6.flowlabel;
 187
 188         /*
 189          *      TCP over IPv4
 190          */
 191
 192         if (addr_type == IPV6_ADDR_MAPPED) {
 193                 u32 exthdrlen = icsk->icsk_ext_hdr_len;
 194                 struct sockaddr_in sin;
 195
 196                 SOCK_DEBUG(sk, "connect: ipv4 mapped\n");
 197
 198                 if (__ipv6_only_sock(sk))
 199                         return -ENETUNREACH;
 200
 201                 sin.sin_family = AF_INET;
 202                 sin.sin_port = usin->sin6_port;
 203                 sin.sin_addr.s_addr = usin->sin6_addr.s6_addr32[3];
 204
 205                 icsk->icsk_af_ops = &ipv6_mapped;
 206                 sk->sk_backlog_rcv = tcp_v4_do_rcv;
 207 #ifdef CONFIG_TCP_MD5SIG
 208                 tp->af_specific = &tcp_sock_ipv6_mapped_specific;
 209 #endif
 210
 211                 err = tcp_v4_connect(sk, (struct sockaddr *)&sin, sizeof(sin));
 212
 213                 if (err) {
 214                         icsk->icsk_ext_hdr_len = exthdrlen;
 215                         icsk->icsk_af_ops = &ipv6_specific;
 216                         sk->sk_backlog_rcv = tcp_v6_do_rcv;
 217 #ifdef CONFIG_TCP_MD5SIG
 218                         tp->af_specific = &tcp_sock_ipv6_specific;
 219 #endif
 220                         goto failure;
 221                 }
 222                 np->saddr = sk->sk_v6_rcv_saddr;
 223
 224                 return err;
 225         }
 226
 227         if (!ipv6_addr_any(&sk->sk_v6_rcv_saddr))
 228                 saddr = &sk->sk_v6_rcv_saddr;
 229
 230         fl6.flowi6_proto = IPPROTO_TCP;
 231         fl6.daddr = sk->sk_v6_daddr;
 232         fl6.saddr = saddr ? *saddr : np->saddr;
 233         fl6.flowi6_oif = sk->sk_bound_dev_if;
 234         fl6.flowi6_mark = sk->sk_mark;
 235         fl6.fl6_dport = usin->sin6_port;
 236         fl6.fl6_sport = inet->inet_sport;
 237         fl6.flowi6_uid = sk->sk_uid;
 238
 239         opt = rcu_dereference_protected(np->opt, sock_owned_by_user(sk));
 240         final_p = fl6_update_dst(&fl6, opt, &final);
 241
 242         security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));
 243
 244         dst = ip6_dst_lookup_flow(sk, &fl6, final_p);
 245         if (IS_ERR(dst)) {
 246                 err = PTR_ERR(dst);
 247                 goto failure;
 248         }
 249
 250         if (!saddr) {
 251                 saddr = &fl6.saddr;
 252                 sk->sk_v6_rcv_saddr = *saddr;
 253         }
 254
 255         /* set the source address */
 256         np->saddr = *saddr;
 257         inet->inet_rcv_saddr = LOOPBACK4_IPV6;
 258
 259         sk->sk_gso_type = SKB_GSO_TCPV6;
 260         ip6_dst_store(sk, dst, NULL, NULL);
 261
 262         if (tcp_death_row.sysctl_tw_recycle &&
 263             !tp->rx_opt.ts_recent_stamp &&
 264             ipv6_addr_equal(&fl6.daddr, &sk->sk_v6_daddr))
 265                 tcp_fetch_timewait_stamp(sk, dst);
 266
 267         icsk->icsk_ext_hdr_len = 0;
 268         if (opt)
 269                 icsk->icsk_ext_hdr_len = opt->opt_flen +
 270                                          opt->opt_nflen;
 271
 272         tp->rx_opt.mss_clamp = IPV6_MIN_MTU - sizeof(struct tcphdr) - sizeof(struct ipv6hdr);
 273
 274         inet->inet_dport = usin->sin6_port;
 275
 276         tcp_set_state(sk, TCP_SYN_SENT);
 277         err = inet6_hash_connect(&tcp_death_row, sk);
 278         if (err)
 279                 goto late_failure;
 280
 281         sk_set_txhash(sk);
 282
 283         if (!tp->write_seq && likely(!tp->repair))
 284                 tp->write_seq = secure_tcpv6_sequence_number(np->saddr.s6_addr32,
 285                                                              sk->sk_v6_daddr.s6_addr32,
 286                                                              inet->inet_sport,
 287                                                              inet->inet_dport);
 288
 289         err = tcp_connect(sk);
 290         if (err)
 291                 goto late_failure;
 292
 293         return 0;
 294
 295 late_failure:
 296         tcp_set_state(sk, TCP_CLOSE);
 297         __sk_dst_reset(sk);
 298 failure:
 299         inet->inet_dport = 0;
 300         sk->sk_route_caps = 0;
 301         return err;
 302 }
 303
 304 static void tcp_v6_mtu_reduced(struct sock *sk)
 305 {
 306         struct dst_entry *dst;
 307
 308         if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE))
 309                 return;
 310
 311         dst = inet6_csk_update_pmtu(sk, tcp_sk(sk)->mtu_info);
 312         if (!dst)
 313                 return;
 314
 315         if (inet_csk(sk)->icsk_pmtu_cookie > dst_mtu(dst)) {
 316                 tcp_sync_mss(sk, dst_mtu(dst));
 317                 tcp_simple_retransmit(sk);
 318         }
 319 }
 320
 321 static void tcp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 322                 u8 type, u8 code, int offset, __be32 info)
 323 {
 324         const struct ipv6hdr *hdr = (const struct ipv6hdr *)skb->data;
 325         const struct tcphdr *th = (struct tcphdr *)(skb->data+offset);
 326         struct net *net = dev_net(skb->dev);
 327         struct request_sock *fastopen;
 328         struct ipv6_pinfo *np;
 329         struct tcp_sock *tp;
 330         __u32 seq, snd_una;
 331         struct sock *sk;
 332         bool fatal;
 333         int err;
 334
 335         sk = __inet6_lookup_established(net, &tcp_hashinfo,
 336                                         &hdr->daddr, th->dest,
 337                                         &hdr->saddr, ntohs(th->source),
 338                                         skb->dev->ifindex);
 339
 340         if (!sk) {
 341                 ICMP6_INC_STATS_BH(net, __in6_dev_get(skb->dev),
 342                                    ICMP6_MIB_INERRORS);
 343                 return;
 344         }
 345
 346         if (sk->sk_state == TCP_TIME_WAIT) {
 347                 inet_twsk_put(inet_twsk(sk));
 348                 return;
 349         }
 350         seq = ntohl(th->seq);
 351         fatal = icmpv6_err_convert(type, code, &err);
 352         if (sk->sk_state == TCP_NEW_SYN_RECV)
 353                 return tcp_req_err(sk, seq, fatal);
 354
 355         bh_lock_sock(sk);
 356         if (sock_owned_by_user(sk) && type != ICMPV6_PKT_TOOBIG)
 357                 NET_INC_STATS_BH(net, LINUX_MIB_LOCKDROPPEDICMPS);
 358
 359         if (sk->sk_state == TCP_CLOSE)
 360                 goto out;
 361
 362         if (ipv6_hdr(skb)->hop_limit < inet6_sk(sk)->min_hopcount) {
 363                 NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP);
 364                 goto out;
 365         }
 366
 367         tp = tcp_sk(sk);
 368         /* XXX (TFO) - tp->snd_una should be ISN (tcp_create_openreq_child() */
 369         fastopen = tp->fastopen_rsk;
 370         snd_una = fastopen ? tcp_rsk(fastopen)->snt_isn : tp->snd_una;
 371         if (sk->sk_state != TCP_LISTEN &&
 372             !between(seq, snd_una, tp->snd_nxt)) {
 373                 NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
 374                 goto out;
 375         }
 376
 377         np = inet6_sk(sk);
 378
 379         if (type == NDISC_REDIRECT) {
 380                 struct dst_entry *dst = __sk_dst_check(sk, np->dst_cookie);
 381
 382                 if (dst)
 383                         dst->ops->redirect(dst, sk, skb);
 384                 goto out;
 385         }
 386
 387         if (type == ICMPV6_PKT_TOOBIG) {
 388                 /* We are not interested in TCP_LISTEN and open_requests
 389                  * (SYN-ACKs send out by Linux are always <576bytes so
 390                  * they should go through unfragmented).
 391                  */
 392                 if (sk->sk_state == TCP_LISTEN)
 393                         goto out;
 394
 395                 if (!ip6_sk_accept_pmtu(sk))
 396                         goto out;
 397
 398                 tp->mtu_info = ntohl(info);
 399                 if (!sock_owned_by_user(sk))
 400                         tcp_v6_mtu_reduced(sk);
 401                 else if (!test_and_set_bit(TCP_MTU_REDUCED_DEFERRED,
 402                                            &tp->tsq_flags))
 403                         sock_hold(sk);
 404                 goto out;
 405         }
 406
 407
 408         /* Might be for an request_sock */
 409         switch (sk->sk_state) {
 410         case TCP_SYN_SENT:
 411         case TCP_SYN_RECV:
 412                 /* Only in fast or simultaneous open. If a fast open socket is
 413                  * is already accepted it is treated as a connected one below.
 414                  */
 415                 if (fastopen && !fastopen->sk)
 416                         break;
 417
 418                 if (!sock_owned_by_user(sk)) {
 419                         sk->sk_err = err;
 420                         sk->sk_error_report(sk);                /* Wake people up to see the error (see connect in sock.c) */
 421
 422                         tcp_done(sk);
 423                 } else
 424                         sk->sk_err_soft = err;
 425                 goto out;
 426         }
 427
 428         if (!sock_owned_by_user(sk) && np->recverr) {
 429                 sk->sk_err = err;
 430                 sk->sk_error_report(sk);
 431         } else
 432                 sk->sk_err_soft = err;
 433
 434 out:
 435         bh_unlock_sock(sk);
 436         sock_put(sk);
 437 }
 438
 439
 440 static int tcp_v6_send_synack(const struct sock *sk, struct dst_entry *dst,
 441                               struct flowi *fl,
 442                               struct request_sock *req,
 443                               struct tcp_fastopen_cookie *foc,
 444                               bool attach_req)
 445 {
 446         struct inet_request_sock *ireq = inet_rsk(req);
 447         struct ipv6_pinfo *np = inet6_sk(sk);
 448         struct flowi6 *fl6 = &fl->u.ip6;
 449         struct sk_buff *skb;
 450         int err = -ENOMEM;
 451
 452         /* First, grab a route. */
 453         if (!dst && (dst = inet6_csk_route_req(sk, fl6, req,
 454                                                IPPROTO_TCP)) == NULL)
 455                 goto done;
 456
 457         skb = tcp_make_synack(sk, dst, req, foc, attach_req);
 458
 459         if (skb) {
 460                 __tcp_v6_send_check(skb, &ireq->ir_v6_loc_addr,
 461                                     &ireq->ir_v6_rmt_addr);
 462
 463                 fl6->daddr = ireq->ir_v6_rmt_addr;
 464                 if (np->repflow && ireq->pktopts)
 465                         fl6->flowlabel = ip6_flowlabel(ipv6_hdr(ireq->pktopts));
 466
 467                 rcu_read_lock();
 468                 err = ip6_xmit(sk, skb, fl6, rcu_dereference(np->opt),
 469                                np->tclass);
 470                 rcu_read_unlock();
 471                 err = net_xmit_eval(err);
 472         }
 473
 474 done:
 475         return err;
 476 }
 477
 478
 479 static void tcp_v6_reqsk_destructor(struct request_sock *req)
 480 {
 481         kfree_skb(inet_rsk(req)->pktopts);
 482 }
 483
 484 #ifdef CONFIG_TCP_MD5SIG
 485 static struct tcp_md5sig_key *tcp_v6_md5_do_lookup(const struct sock *sk,
 486                                                    const struct in6_addr *addr)
 487 {
 488         return tcp_md5_do_lookup(sk, (union tcp_md5_addr *)addr, AF_INET6);
 489 }
 490
 491 static struct tcp_md5sig_key *tcp_v6_md5_lookup(const struct sock *sk,
 492                                                 const struct sock *addr_sk)
 493 {
 494         return tcp_v6_md5_do_lookup(sk, &addr_sk->sk_v6_daddr);
 495 }
 496
 497 static int tcp_v6_parse_md5_keys(struct sock *sk, char __user *optval,
 498                                  int optlen)
 499 {
 500         struct tcp_md5sig cmd;
 501         struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)&cmd.tcpm_addr;
 502
 503         if (optlen < sizeof(cmd))
 504                 return -EINVAL;
 505
 506         if (copy_from_user(&cmd, optval, sizeof(cmd)))
 507                 return -EFAULT;
 508
 509         if (sin6->sin6_family != AF_INET6)
 510                 return -EINVAL;
 511
 512         if (!cmd.tcpm_keylen) {
 513                 if (ipv6_addr_v4mapped(&sin6->sin6_addr))
 514                         return tcp_md5_do_del(sk, (union tcp_md5_addr *)&sin6->sin6_addr.s6_addr32[3],
 515                                               AF_INET);
 516                 return tcp_md5_do_del(sk, (union tcp_md5_addr *)&sin6->sin6_addr,
 517                                       AF_INET6);
 518         }
 519
 520         if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN)
 521                 return -EINVAL;
 522
 523         if (ipv6_addr_v4mapped(&sin6->sin6_addr))
 524                 return tcp_md5_do_add(sk, (union tcp_md5_addr *)&sin6->sin6_addr.s6_addr32[3],
 525                                       AF_INET, cmd.tcpm_key, cmd.tcpm_keylen, GFP_KERNEL);
 526
 527         return tcp_md5_do_add(sk, (union tcp_md5_addr *)&sin6->sin6_addr,
 528                               AF_INET6, cmd.tcpm_key, cmd.tcpm_keylen, GFP_KERNEL);
 529 }
 530
 531 static int tcp_v6_md5_hash_pseudoheader(struct tcp_md5sig_pool *hp,
 532                                         const struct in6_addr *daddr,
 533                                         const struct in6_addr *saddr, int nbytes)
 534 {
 535         struct tcp6_pseudohdr *bp;
 536         struct scatterlist sg;
 537
 538         bp = &hp->md5_blk.ip6;
 539         /* 1. TCP pseudo-header (RFC2460) */
 540         bp->saddr = *saddr;
 541         bp->daddr = *daddr;
 542         bp->protocol = cpu_to_be32(IPPROTO_TCP);
 543         bp->len = cpu_to_be32(nbytes);
 544
 545         sg_init_one(&sg, bp, sizeof(*bp));
 546         return crypto_hash_update(&hp->md5_desc, &sg, sizeof(*bp));
 547 }
 548
 549 static int tcp_v6_md5_hash_hdr(char *md5_hash, struct tcp_md5sig_key *key,
 550                                const struct in6_addr *daddr, struct in6_addr *saddr,
 551                                const struct tcphdr *th)
 552 {
 553         struct tcp_md5sig_pool *hp;
 554         struct hash_desc *desc;
 555
 556         hp = tcp_get_md5sig_pool();
 557         if (!hp)
 558                 goto clear_hash_noput;
 559         desc = &hp->md5_desc;
 560
 561         if (crypto_hash_init(desc))
 562                 goto clear_hash;
 563         if (tcp_v6_md5_hash_pseudoheader(hp, daddr, saddr, th->doff << 2))
 564                 goto clear_hash;
 565         if (tcp_md5_hash_header(hp, th))
 566                 goto clear_hash;
 567         if (tcp_md5_hash_key(hp, key))
 568                 goto clear_hash;
 569         if (crypto_hash_final(desc, md5_hash))
 570                 goto clear_hash;
 571
 572         tcp_put_md5sig_pool();
 573         return 0;
 574
 575 clear_hash:
 576         tcp_put_md5sig_pool();
 577 clear_hash_noput:
 578         memset(md5_hash, 0, 16);
 579         return 1;
 580 }
 581
 582 static int tcp_v6_md5_hash_skb(char *md5_hash,
 583                                const struct tcp_md5sig_key *key,
 584                                const struct sock *sk,
 585                                const struct sk_buff *skb)
 586 {
 587         const struct in6_addr *saddr, *daddr;
 588         struct tcp_md5sig_pool *hp;
 589         struct hash_desc *desc;
 590         const struct tcphdr *th = tcp_hdr(skb);
 591
 592         if (sk) { /* valid for establish/request sockets */
 593                 saddr = &sk->sk_v6_rcv_saddr;
 594                 daddr = &sk->sk_v6_daddr;
 595         } else {
 596                 const struct ipv6hdr *ip6h = ipv6_hdr(skb);
 597                 saddr = &ip6h->saddr;
 598                 daddr = &ip6h->daddr;
 599         }
 600
 601         hp = tcp_get_md5sig_pool();
 602         if (!hp)
 603                 goto clear_hash_noput;
 604         desc = &hp->md5_desc;
 605
 606         if (crypto_hash_init(desc))
 607                 goto clear_hash;
 608
 609         if (tcp_v6_md5_hash_pseudoheader(hp, daddr, saddr, skb->len))
 610                 goto clear_hash;
 611         if (tcp_md5_hash_header(hp, th))
 612                 goto clear_hash;
 613         if (tcp_md5_hash_skb_data(hp, skb, th->doff << 2))
 614                 goto clear_hash;
 615         if (tcp_md5_hash_key(hp, key))
 616                 goto clear_hash;
 617         if (crypto_hash_final(desc, md5_hash))
 618                 goto clear_hash;
 619
 620         tcp_put_md5sig_pool();
 621         return 0;
 622
 623 clear_hash:
 624         tcp_put_md5sig_pool();
 625 clear_hash_noput:
 626         memset(md5_hash, 0, 16);
 627         return 1;
 628 }
 629
 630 #endif
 631
 632 static bool tcp_v6_inbound_md5_hash(const struct sock *sk,
 633                                     const struct sk_buff *skb)
 634 {
 635 #ifdef CONFIG_TCP_MD5SIG
 636         const __u8 *hash_location = NULL;
 637         struct tcp_md5sig_key *hash_expected;
 638         const struct ipv6hdr *ip6h = ipv6_hdr(skb);
 639         const struct tcphdr *th = tcp_hdr(skb);
 640         int genhash;
 641         u8 newhash[16];
 642
 643         hash_expected = tcp_v6_md5_do_lookup(sk, &ip6h->saddr);
 644         hash_location = tcp_parse_md5sig_option(th);
 645
 646         /* We've parsed the options - do we have a hash? */
 647         if (!hash_expected && !hash_location)
 648                 return false;
 649
 650         if (hash_expected && !hash_location) {
 651                 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5NOTFOUND);
 652                 return true;
 653         }
 654
 655         if (!hash_expected && hash_location) {
 656                 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5UNEXPECTED);
 657                 return true;
 658         }
 659
 660         /* check the signature */
 661         genhash = tcp_v6_md5_hash_skb(newhash,
 662                                       hash_expected,
 663                                       NULL, skb);
 664
 665         if (genhash || memcmp(hash_location, newhash, 16) != 0) {
 666                 net_info_ratelimited("MD5 Hash %s for [%pI6c]:%u->[%pI6c]:%u\n",
 667                                      genhash ? "failed" : "mismatch",
 668                                      &ip6h->saddr, ntohs(th->source),
 669                                      &ip6h->daddr, ntohs(th->dest));
 670                 return true;
 671         }
 672 #endif
 673         return false;
 674 }
 675
 676 static void tcp_v6_init_req(struct request_sock *req,
 677                             const struct sock *sk_listener,
 678                             struct sk_buff *skb)
 679 {
 680         struct inet_request_sock *ireq = inet_rsk(req);
 681         const struct ipv6_pinfo *np = inet6_sk(sk_listener);
 682
 683         ireq->ir_v6_rmt_addr = ipv6_hdr(skb)->saddr;
 684         ireq->ir_v6_loc_addr = ipv6_hdr(skb)->daddr;
 685
 686         /* So that link locals have meaning */
 687         if (!sk_listener->sk_bound_dev_if &&
 688             ipv6_addr_type(&ireq->ir_v6_rmt_addr) & IPV6_ADDR_LINKLOCAL)
 689                 ireq->ir_iif = tcp_v6_iif(skb);
 690
 691         if (!TCP_SKB_CB(skb)->tcp_tw_isn &&
 692             (ipv6_opt_accepted(sk_listener, skb, &TCP_SKB_CB(skb)->header.h6) ||
 693              np->rxopt.bits.rxinfo ||
 694              np->rxopt.bits.rxoinfo || np->rxopt.bits.rxhlim ||
 695              np->rxopt.bits.rxohlim || np->repflow)) {
 696                 atomic_inc(&skb->users);
 697                 ireq->pktopts = skb;
 698         }
 699 }
 700
 701 static struct dst_entry *tcp_v6_route_req(const struct sock *sk,
 702                                           struct flowi *fl,
 703                                           const struct request_sock *req,
 704                                           bool *strict)
 705 {
 706         if (strict)
 707                 *strict = true;
 708         return inet6_csk_route_req(sk, &fl->u.ip6, req, IPPROTO_TCP);
 709 }
 710
 711 struct request_sock_ops tcp6_request_sock_ops __read_mostly = {
 712         .family         =       AF_INET6,
 713         .obj_size       =       sizeof(struct tcp6_request_sock),
 714         .rtx_syn_ack    =       tcp_rtx_synack,
 715         .send_ack       =       tcp_v6_reqsk_send_ack,
 716         .destructor     =       tcp_v6_reqsk_destructor,
 717         .send_reset     =       tcp_v6_send_reset,
 718         .syn_ack_timeout =      tcp_syn_ack_timeout,
 719 };
 720
 721 static const struct tcp_request_sock_ops tcp_request_sock_ipv6_ops = {
 722         .mss_clamp      =       IPV6_MIN_MTU - sizeof(struct tcphdr) -
 723                                 sizeof(struct ipv6hdr),
 724 #ifdef CONFIG_TCP_MD5SIG
 725         .req_md5_lookup =       tcp_v6_md5_lookup,
 726         .calc_md5_hash  =       tcp_v6_md5_hash_skb,
 727 #endif
 728         .init_req       =       tcp_v6_init_req,
 729 #ifdef CONFIG_SYN_COOKIES
 730         .cookie_init_seq =      cookie_v6_init_sequence,
 731 #endif
 732         .route_req      =       tcp_v6_route_req,
 733         .init_seq       =       tcp_v6_init_sequence,
 734         .send_synack    =       tcp_v6_send_synack,
 735 };
 736
 737 static void tcp_v6_send_response(const struct sock *sk, struct sk_buff *skb, u32 seq,
 738                                  u32 ack, u32 win, u32 tsval, u32 tsecr,
 739                                  int oif, struct tcp_md5sig_key *key, int rst,
 740                                  u8 tclass, u32 label)
 741 {
 742         const struct tcphdr *th = tcp_hdr(skb);
 743         struct tcphdr *t1;
 744         struct sk_buff *buff;
 745         struct flowi6 fl6;
 746         struct net *net = sk ? sock_net(sk) : dev_net(skb_dst(skb)->dev);
 747         struct sock *ctl_sk = net->ipv6.tcp_sk;
 748         unsigned int tot_len = sizeof(struct tcphdr);
 749         struct dst_entry *dst;
 750         __be32 *topt;
 751
 752         if (tsecr)
 753                 tot_len += TCPOLEN_TSTAMP_ALIGNED;
 754 #ifdef CONFIG_TCP_MD5SIG
 755         if (key)
 756                 tot_len += TCPOLEN_MD5SIG_ALIGNED;
 757 #endif
 758
 759         buff = alloc_skb(MAX_HEADER + sizeof(struct ipv6hdr) + tot_len,
 760                          GFP_ATOMIC);
 761         if (!buff)
 762                 return;
 763
 764         skb_reserve(buff, MAX_HEADER + sizeof(struct ipv6hdr) + tot_len);
 765
 766         t1 = (struct tcphdr *) skb_push(buff, tot_len);
 767         skb_reset_transport_header(buff);
 768
 769         /* Swap the send and the receive. */
 770         memset(t1, 0, sizeof(*t1));
 771         t1->dest = th->source;
 772         t1->source = th->dest;
 773         t1->doff = tot_len / 4;
 774         t1->seq = htonl(seq);
 775         t1->ack_seq = htonl(ack);
 776         t1->ack = !rst || !th->ack;
 777         t1->rst = rst;
 778         t1->window = htons(win);
 779
 780         topt = (__be32 *)(t1 + 1);
 781
 782         if (tsecr) {
 783                 *topt++ = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
 784                                 (TCPOPT_TIMESTAMP << 8) | TCPOLEN_TIMESTAMP);
 785                 *topt++ = htonl(tsval);
 786                 *topt++ = htonl(tsecr);
 787         }
 788
 789 #ifdef CONFIG_TCP_MD5SIG
 790         if (key) {
 791                 *topt++ = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
 792                                 (TCPOPT_MD5SIG << 8) | TCPOLEN_MD5SIG);
 793                 tcp_v6_md5_hash_hdr((__u8 *)topt, key,
 794                                     &ipv6_hdr(skb)->saddr,
 795                                     &ipv6_hdr(skb)->daddr, t1);
 796         }
 797 #endif
 798
 799         memset(&fl6, 0, sizeof(fl6));
 800         fl6.daddr = ipv6_hdr(skb)->saddr;
 801         fl6.saddr = ipv6_hdr(skb)->daddr;
 802         fl6.flowlabel = label;
 803
 804         buff->ip_summed = CHECKSUM_PARTIAL;
 805         buff->csum = 0;
 806
 807         __tcp_v6_send_check(buff, &fl6.saddr, &fl6.daddr);
 808
 809         fl6.flowi6_proto = IPPROTO_TCP;
 810         if (rt6_need_strict(&fl6.daddr) && !oif)
 811                 fl6.flowi6_oif = tcp_v6_iif(skb);
 812         else
 813                 fl6.flowi6_oif = oif;
 814         fl6.flowi6_mark = IP6_REPLY_MARK(net, skb->mark);
 815         fl6.fl6_dport = t1->dest;
 816         fl6.fl6_sport = t1->source;
 817         fl6.flowi6_uid = sock_net_uid(net, sk && sk_fullsock(sk) ? sk : NULL);
 818         security_skb_classify_flow(skb, flowi6_to_flowi(&fl6));
 819
 820         /* Pass a socket to ip6_dst_lookup either it is for RST
 821          * Underlying function will use this to retrieve the network
 822          * namespace
 823          */
 824         dst = ip6_dst_lookup_flow(ctl_sk, &fl6, NULL);
 825         if (!IS_ERR(dst)) {
 826                 skb_dst_set(buff, dst);
 827                 ip6_xmit(ctl_sk, buff, &fl6, NULL, tclass);
 828                 TCP_INC_STATS_BH(net, TCP_MIB_OUTSEGS);
 829                 if (rst)
 830                         TCP_INC_STATS_BH(net, TCP_MIB_OUTRSTS);
 831                 return;
 832         }
 833
 834         kfree_skb(buff);
 835 }
 836
 837 static void tcp_v6_send_reset(const struct sock *sk, struct sk_buff *skb)
 838 {
 839         const struct tcphdr *th = tcp_hdr(skb);
 840         u32 seq = 0, ack_seq = 0;
 841         struct tcp_md5sig_key *key = NULL;
 842 #ifdef CONFIG_TCP_MD5SIG
 843         const __u8 *hash_location = NULL;
 844         struct ipv6hdr *ipv6h = ipv6_hdr(skb);
 845         unsigned char newhash[16];
 846         int genhash;
 847         struct sock *sk1 = NULL;
 848 #endif
 849         int oif;
 850
 851         if (th->rst)
 852                 return;
 853
 854         /* If sk not NULL, it means we did a successful lookup and incoming
 855          * route had to be correct. prequeue might have dropped our dst.
 856          */
 857         if (!sk && !ipv6_unicast_destination(skb))
 858                 return;
 859
 860 #ifdef CONFIG_TCP_MD5SIG
 861         hash_location = tcp_parse_md5sig_option(th);
 862         if (!sk && hash_location) {
 863                 /*
 864                  * active side is lost. Try to find listening socket through
 865                  * source port, and then find md5 key through listening socket.
 866                  * we are not loose security here:
 867                  * Incoming packet is checked with md5 hash with finding key,
 868                  * no RST generated if md5 hash doesn't match.
 869                  */
 870                 sk1 = inet6_lookup_listener(dev_net(skb_dst(skb)->dev),
 871                                            &tcp_hashinfo, &ipv6h->saddr,
 872                                            th->source, &ipv6h->daddr,
 873                                            ntohs(th->source), tcp_v6_iif(skb));
 874                 if (!sk1)
 875                         return;
 876
 877                 rcu_read_lock();
 878                 key = tcp_v6_md5_do_lookup(sk1, &ipv6h->saddr);
 879                 if (!key)
 880                         goto release_sk1;
 881
 882                 genhash = tcp_v6_md5_hash_skb(newhash, key, NULL, skb);
 883                 if (genhash || memcmp(hash_location, newhash, 16) != 0)
 884                         goto release_sk1;
 885         } else {
 886                 key = sk ? tcp_v6_md5_do_lookup(sk, &ipv6h->saddr) : NULL;
 887         }
 888 #endif
 889
 890         if (th->ack)
 891                 seq = ntohl(th->ack_seq);
 892         else
 893                 ack_seq = ntohl(th->seq) + th->syn + th->fin + skb->len -
 894                           (th->doff << 2);
 895
 896         oif = sk ? sk->sk_bound_dev_if : 0;
 897         tcp_v6_send_response(sk, skb, seq, ack_seq, 0, 0, 0, oif, key, 1, 0, 0);
 898
 899 #ifdef CONFIG_TCP_MD5SIG
 900 release_sk1:
 901         if (sk1) {
 902                 rcu_read_unlock();
 903                 sock_put(sk1);
 904         }
 905 #endif
 906 }
 907
 908 static void tcp_v6_send_ack(const struct sock *sk, struct sk_buff *skb, u32 seq,
 909                             u32 ack, u32 win, u32 tsval, u32 tsecr, int oif,
 910                             struct tcp_md5sig_key *key, u8 tclass,
 911                             u32 label)
 912 {
 913         tcp_v6_send_response(sk, skb, seq, ack, win, tsval, tsecr, oif, key, 0,
 914                              tclass, label);
 915 }
 916
 917 static void tcp_v6_timewait_ack(struct sock *sk, struct sk_buff *skb)
 918 {
 919         struct inet_timewait_sock *tw = inet_twsk(sk);
 920         struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
 921
 922         tcp_v6_send_ack(sk, skb, tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
 923                         tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
 924                         tcp_time_stamp + tcptw->tw_ts_offset,
 925                         tcptw->tw_ts_recent, tw->tw_bound_dev_if, tcp_twsk_md5_key(tcptw),
 926                         tw->tw_tclass, cpu_to_be32(tw->tw_flowlabel));
 927
 928         inet_twsk_put(tw);
 929 }
 930
 931 static void tcp_v6_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb,
 932                                   struct request_sock *req)
 933 {
 934         /* sk->sk_state == TCP_LISTEN -> for regular TCP_SYN_RECV
 935          * sk->sk_state == TCP_SYN_RECV -> for Fast Open.
 936          */
 937         /* RFC 7323 2.3
 938          * The window field (SEG.WND) of every outgoing segment, with the
 939          * exception of <SYN> segments, MUST be right-shifted by
 940          * Rcv.Wind.Shift bits:
 941          */
 942         tcp_v6_send_ack(sk, skb, (sk->sk_state == TCP_LISTEN) ?
 943                         tcp_rsk(req)->snt_isn + 1 : tcp_sk(sk)->snd_nxt,
 944                         tcp_rsk(req)->rcv_nxt,
 945                         req->rsk_rcv_wnd >> inet_rsk(req)->rcv_wscale,
 946                         tcp_time_stamp, req->ts_recent, sk->sk_bound_dev_if,
 947                         tcp_v6_md5_do_lookup(sk, &ipv6_hdr(skb)->daddr),
 948                         0, 0);
 949 }
 950
 951
 952 static struct sock *tcp_v6_cookie_check(struct sock *sk, struct sk_buff *skb)
 953 {
 954 #ifdef CONFIG_SYN_COOKIES
 955         const struct tcphdr *th = tcp_hdr(skb);
 956
 957         if (!th->syn)
 958                 sk = cookie_v6_check(sk, skb);
 959 #endif
 960         return sk;
 961 }
 962
 963 static int tcp_v6_conn_request(struct sock *sk, struct sk_buff *skb)
 964 {
 965         if (skb->protocol == htons(ETH_P_IP))
 966                 return tcp_v4_conn_request(sk, skb);
 967
 968         if (!ipv6_unicast_destination(skb))
 969                 goto drop;
 970
 971         return tcp_conn_request(&tcp6_request_sock_ops,
 972                                 &tcp_request_sock_ipv6_ops, sk, skb);
 973
 974 drop:
 975         NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
 976         return 0; /* don't send reset */
 977 }
 978
 979 static void tcp_v6_restore_cb(struct sk_buff *skb)
 980 {
 981         /* We need to move header back to the beginning if xfrm6_policy_check()
 982          * and tcp_v6_fill_cb() are going to be called again.
 983          * ip6_datagram_recv_specific_ctl() also expects IP6CB to be there.
 984          */
 985         memmove(IP6CB(skb), &TCP_SKB_CB(skb)->header.h6,
 986                 sizeof(struct inet6_skb_parm));
 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 = rcu_dereference(np->opt);
1126         if (opt) {
1127                 opt = ipv6_dup_options(newsk, opt);
1128                 RCU_INIT_POINTER(newnp->opt, opt);
1129         }
1130         inet_csk(newsk)->icsk_ext_hdr_len = 0;
1131         if (opt)
1132                 inet_csk(newsk)->icsk_ext_hdr_len = opt->opt_nflen +
1133                                                     opt->opt_flen;
1134
1135         tcp_ca_openreq_child(newsk, dst);
1136
1137         tcp_sync_mss(newsk, dst_mtu(dst));
1138         newtp->advmss = dst_metric_advmss(dst);
1139         if (tcp_sk(sk)->rx_opt.user_mss &&
1140             tcp_sk(sk)->rx_opt.user_mss < newtp->advmss)
1141                 newtp->advmss = tcp_sk(sk)->rx_opt.user_mss;
1142
1143         tcp_initialize_rcv_mss(newsk);
1144
1145         newinet->inet_daddr = newinet->inet_saddr = LOOPBACK4_IPV6;
1146         newinet->inet_rcv_saddr = LOOPBACK4_IPV6;
1147
1148 #ifdef CONFIG_TCP_MD5SIG
1149         /* Copy over the MD5 key from the original socket */
1150         key = tcp_v6_md5_do_lookup(sk, &newsk->sk_v6_daddr);
1151         if (key) {
1152                 /* We're using one, so create a matching key
1153                  * on the newsk structure. If we fail to get
1154                  * memory, then we end up not copying the key
1155                  * across. Shucks.
1156                  */
1157                 tcp_md5_do_add(newsk, (union tcp_md5_addr *)&newsk->sk_v6_daddr,
1158                                AF_INET6, key->key, key->keylen,
1159                                sk_gfp_atomic(sk, GFP_ATOMIC));
1160         }
1161 #endif
1162
1163         if (__inet_inherit_port(sk, newsk) < 0) {
1164                 inet_csk_prepare_forced_close(newsk);
1165                 tcp_done(newsk);
1166                 goto out;
1167         }
1168         *own_req = inet_ehash_nolisten(newsk, req_to_sk(req_unhash));
1169         if (*own_req) {
1170                 tcp_move_syn(newtp, req);
1171
1172                 /* Clone pktoptions received with SYN, if we own the req */
1173                 if (ireq->pktopts) {
1174                         newnp->pktoptions = skb_clone(ireq->pktopts,
1175                                                       sk_gfp_atomic(sk, GFP_ATOMIC));
1176                         consume_skb(ireq->pktopts);
1177                         ireq->pktopts = NULL;
1178                         if (newnp->pktoptions) {
1179                                 tcp_v6_restore_cb(newnp->pktoptions);
1180                                 skb_set_owner_r(newnp->pktoptions, newsk);
1181                         }
1182                 }
1183         }
1184
1185         return newsk;
1186
1187 out_overflow:
1188         NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
1189 out_nonewsk:
1190         dst_release(dst);
1191 out:
1192         NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
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 (tcp_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_atomic(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_BH(sock_net(sk), TCP_MIB_CSUMERRORS);
1300         TCP_INC_STATS_BH(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                         tcp_v6_restore_cb(opt_skb);
1326                         opt_skb = xchg(&np->pktoptions, opt_skb);
1327                 } else {
1328                         __kfree_skb(opt_skb);
1329                         opt_skb = xchg(&np->pktoptions, NULL);
1330                 }
1331         }
1332
1333         kfree_skb(opt_skb);
1334         return 0;
1335 }
1336
1337 static void tcp_v6_fill_cb(struct sk_buff *skb, const struct ipv6hdr *hdr,
1338                            const struct tcphdr *th)
1339 {
1340         /* This is tricky: we move IP6CB at its correct location into
1341          * TCP_SKB_CB(). It must be done after xfrm6_policy_check(), because
1342          * _decode_session6() uses IP6CB().
1343          * barrier() makes sure compiler won't play aliasing games.
1344          */
1345         memmove(&TCP_SKB_CB(skb)->header.h6, IP6CB(skb),
1346                 sizeof(struct inet6_skb_parm));
1347         barrier();
1348
1349         TCP_SKB_CB(skb)->seq = ntohl(th->seq);
1350         TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
1351                                     skb->len - th->doff*4);
1352         TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
1353         TCP_SKB_CB(skb)->tcp_flags = tcp_flag_byte(th);
1354         TCP_SKB_CB(skb)->tcp_tw_isn = 0;
1355         TCP_SKB_CB(skb)->ip_dsfield = ipv6_get_dsfield(hdr);
1356         TCP_SKB_CB(skb)->sacked = 0;
1357 }
1358
1359 static int tcp_v6_rcv(struct sk_buff *skb)
1360 {
1361         const struct tcphdr *th;
1362         const struct ipv6hdr *hdr;
1363         struct sock *sk;
1364         int ret;
1365         struct net *net = dev_net(skb->dev);
1366
1367         if (skb->pkt_type != PACKET_HOST)
1368                 goto discard_it;
1369
1370         /*
1371          *      Count it even if it's bad.
1372          */
1373         TCP_INC_STATS_BH(net, TCP_MIB_INSEGS);
1374
1375         if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
1376                 goto discard_it;
1377
1378         th = tcp_hdr(skb);
1379
1380         if (th->doff < sizeof(struct tcphdr)/4)
1381                 goto bad_packet;
1382         if (!pskb_may_pull(skb, th->doff*4))
1383                 goto discard_it;
1384
1385         if (skb_checksum_init(skb, IPPROTO_TCP, ip6_compute_pseudo))
1386                 goto csum_error;
1387
1388         th = tcp_hdr(skb);
1389         hdr = ipv6_hdr(skb);
1390
1391 lookup:
1392         sk = __inet6_lookup_skb(&tcp_hashinfo, skb, th->source, th->dest,
1393                                 inet6_iif(skb));
1394         if (!sk)
1395                 goto no_tcp_socket;
1396
1397 process:
1398         if (sk->sk_state == TCP_TIME_WAIT)
1399                 goto do_time_wait;
1400
1401         if (sk->sk_state == TCP_NEW_SYN_RECV) {
1402                 struct request_sock *req = inet_reqsk(sk);
1403                 struct sock *nsk;
1404
1405                 sk = req->rsk_listener;
1406                 tcp_v6_fill_cb(skb, hdr, th);
1407                 if (tcp_v6_inbound_md5_hash(sk, skb)) {
1408                         reqsk_put(req);
1409                         goto discard_it;
1410                 }
1411                 if (unlikely(sk->sk_state != TCP_LISTEN)) {
1412                         inet_csk_reqsk_queue_drop_and_put(sk, req);
1413                         goto lookup;
1414                 }
1415                 sock_hold(sk);
1416                 nsk = tcp_check_req(sk, skb, req, false);
1417                 if (!nsk) {
1418                         reqsk_put(req);
1419                         goto discard_and_relse;
1420                 }
1421                 if (nsk == sk) {
1422                         reqsk_put(req);
1423                         tcp_v6_restore_cb(skb);
1424                 } else if (tcp_child_process(sk, nsk, skb)) {
1425                         tcp_v6_send_reset(nsk, skb);
1426                         goto discard_and_relse;
1427                 } else {
1428                         sock_put(sk);
1429                         return 0;
1430                 }
1431         }
1432         if (hdr->hop_limit < inet6_sk(sk)->min_hopcount) {
1433                 NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP);
1434                 goto discard_and_relse;
1435         }
1436
1437         if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb))
1438                 goto discard_and_relse;
1439
1440         tcp_v6_fill_cb(skb, hdr, th);
1441
1442         if (tcp_v6_inbound_md5_hash(sk, skb))
1443                 goto discard_and_relse;
1444
1445         if (tcp_filter(sk, skb))
1446                 goto discard_and_relse;
1447         th = (const struct tcphdr *)skb->data;
1448         hdr = ipv6_hdr(skb);
1449
1450         skb->dev = NULL;
1451
1452         if (sk->sk_state == TCP_LISTEN) {
1453                 ret = tcp_v6_do_rcv(sk, skb);
1454                 goto put_and_return;
1455         }
1456
1457         sk_incoming_cpu_update(sk);
1458
1459         bh_lock_sock_nested(sk);
1460         tcp_sk(sk)->segs_in += max_t(u16, 1, skb_shinfo(skb)->gso_segs);
1461         ret = 0;
1462         if (!sock_owned_by_user(sk)) {
1463                 if (!tcp_prequeue(sk, skb))
1464                         ret = tcp_v6_do_rcv(sk, skb);
1465         } else if (unlikely(sk_add_backlog(sk, skb,
1466                                            sk->sk_rcvbuf + sk->sk_sndbuf))) {
1467                 bh_unlock_sock(sk);
1468                 NET_INC_STATS_BH(net, LINUX_MIB_TCPBACKLOGDROP);
1469                 goto discard_and_relse;
1470         }
1471         bh_unlock_sock(sk);
1472
1473 put_and_return:
1474         sock_put(sk);
1475         return ret ? -1 : 0;
1476
1477 no_tcp_socket:
1478         if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb))
1479                 goto discard_it;
1480
1481         tcp_v6_fill_cb(skb, hdr, th);
1482
1483         if (tcp_checksum_complete(skb)) {
1484 csum_error:
1485                 TCP_INC_STATS_BH(net, TCP_MIB_CSUMERRORS);
1486 bad_packet:
1487                 TCP_INC_STATS_BH(net, TCP_MIB_INERRS);
1488         } else {
1489                 tcp_v6_send_reset(NULL, skb);
1490         }
1491
1492 discard_it:
1493         kfree_skb(skb);
1494         return 0;
1495
1496 discard_and_relse:
1497         sock_put(sk);
1498         goto discard_it;
1499
1500 do_time_wait:
1501         if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
1502                 inet_twsk_put(inet_twsk(sk));
1503                 goto discard_it;
1504         }
1505
1506         tcp_v6_fill_cb(skb, hdr, th);
1507
1508         if (tcp_checksum_complete(skb)) {
1509                 inet_twsk_put(inet_twsk(sk));
1510                 goto csum_error;
1511         }
1512
1513         switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) {
1514         case TCP_TW_SYN:
1515         {
1516                 struct sock *sk2;
1517
1518                 sk2 = inet6_lookup_listener(dev_net(skb->dev), &tcp_hashinfo,
1519                                             &ipv6_hdr(skb)->saddr, th->source,
1520                                             &ipv6_hdr(skb)->daddr,
1521                                             ntohs(th->dest), tcp_v6_iif(skb));
1522                 if (sk2) {
1523                         struct inet_timewait_sock *tw = inet_twsk(sk);
1524                         inet_twsk_deschedule_put(tw);
1525                         sk = sk2;
1526                         tcp_v6_restore_cb(skb);
1527                         goto process;
1528                 }
1529                 /* Fall through to ACK */
1530         }
1531         case TCP_TW_ACK:
1532                 tcp_v6_timewait_ack(sk, skb);
1533                 break;
1534         case TCP_TW_RST:
1535                 tcp_v6_restore_cb(skb);
1536                 goto no_tcp_socket;
1537         case TCP_TW_SUCCESS:
1538                 ;
1539         }
1540         goto discard_it;
1541 }
1542
1543 static void tcp_v6_early_demux(struct sk_buff *skb)
1544 {
1545         const struct ipv6hdr *hdr;
1546         const struct tcphdr *th;
1547         struct sock *sk;
1548
1549         if (skb->pkt_type != PACKET_HOST)
1550                 return;
1551
1552         if (!pskb_may_pull(skb, skb_transport_offset(skb) + sizeof(struct tcphdr)))
1553                 return;
1554
1555         hdr = ipv6_hdr(skb);
1556         th = tcp_hdr(skb);
1557
1558         if (th->doff < sizeof(struct tcphdr) / 4)
1559                 return;
1560
1561         /* Note : We use inet6_iif() here, not tcp_v6_iif() */
1562         sk = __inet6_lookup_established(dev_net(skb->dev), &tcp_hashinfo,
1563                                         &hdr->saddr, th->source,
1564                                         &hdr->daddr, ntohs(th->dest),
1565                                         inet6_iif(skb));
1566         if (sk) {
1567                 skb->sk = sk;
1568                 skb->destructor = sock_edemux;
1569                 if (sk_fullsock(sk)) {
1570                         struct dst_entry *dst = READ_ONCE(sk->sk_rx_dst);
1571
1572                         if (dst)
1573                                 dst = dst_check(dst, inet6_sk(sk)->rx_dst_cookie);
1574                         if (dst &&
1575                             inet_sk(sk)->rx_dst_ifindex == skb->skb_iif)
1576                                 skb_dst_set_noref(skb, dst);
1577                 }
1578         }
1579 }
1580
1581 static struct timewait_sock_ops tcp6_timewait_sock_ops = {
1582         .twsk_obj_size  = sizeof(struct tcp6_timewait_sock),
1583         .twsk_unique    = tcp_twsk_unique,
1584         .twsk_destructor = tcp_twsk_destructor,
1585 };
1586
1587 static const struct inet_connection_sock_af_ops ipv6_specific = {
1588         .queue_xmit        = inet6_csk_xmit,
1589         .send_check        = tcp_v6_send_check,
1590         .rebuild_header    = inet6_sk_rebuild_header,
1591         .sk_rx_dst_set     = inet6_sk_rx_dst_set,
1592         .conn_request      = tcp_v6_conn_request,
1593         .syn_recv_sock     = tcp_v6_syn_recv_sock,
1594         .net_header_len    = sizeof(struct ipv6hdr),
1595         .net_frag_header_len = sizeof(struct frag_hdr),
1596         .setsockopt        = ipv6_setsockopt,
1597         .getsockopt        = ipv6_getsockopt,
1598         .addr2sockaddr     = inet6_csk_addr2sockaddr,
1599         .sockaddr_len      = sizeof(struct sockaddr_in6),
1600         .bind_conflict     = inet6_csk_bind_conflict,
1601 #ifdef CONFIG_COMPAT
1602         .compat_setsockopt = compat_ipv6_setsockopt,
1603         .compat_getsockopt = compat_ipv6_getsockopt,
1604 #endif
1605         .mtu_reduced       = tcp_v6_mtu_reduced,
1606 };
1607
1608 #ifdef CONFIG_TCP_MD5SIG
1609 static const struct tcp_sock_af_ops tcp_sock_ipv6_specific = {
1610         .md5_lookup     =       tcp_v6_md5_lookup,
1611         .calc_md5_hash  =       tcp_v6_md5_hash_skb,
1612         .md5_parse      =       tcp_v6_parse_md5_keys,
1613 };
1614 #endif
1615
1616 /*
1617  *      TCP over IPv4 via INET6 API
1618  */
1619 static const struct inet_connection_sock_af_ops ipv6_mapped = {
1620         .queue_xmit        = ip_queue_xmit,
1621         .send_check        = tcp_v4_send_check,
1622         .rebuild_header    = inet_sk_rebuild_header,
1623         .sk_rx_dst_set     = inet_sk_rx_dst_set,
1624         .conn_request      = tcp_v6_conn_request,
1625         .syn_recv_sock     = tcp_v6_syn_recv_sock,
1626         .net_header_len    = sizeof(struct iphdr),
1627         .setsockopt        = ipv6_setsockopt,
1628         .getsockopt        = ipv6_getsockopt,
1629         .addr2sockaddr     = inet6_csk_addr2sockaddr,
1630         .sockaddr_len      = sizeof(struct sockaddr_in6),
1631         .bind_conflict     = inet6_csk_bind_conflict,
1632 #ifdef CONFIG_COMPAT
1633         .compat_setsockopt = compat_ipv6_setsockopt,
1634         .compat_getsockopt = compat_ipv6_getsockopt,
1635 #endif
1636         .mtu_reduced       = tcp_v4_mtu_reduced,
1637 };
1638
1639 #ifdef CONFIG_TCP_MD5SIG
1640 static const struct tcp_sock_af_ops tcp_sock_ipv6_mapped_specific = {
1641         .md5_lookup     =       tcp_v4_md5_lookup,
1642         .calc_md5_hash  =       tcp_v4_md5_hash_skb,
1643         .md5_parse      =       tcp_v6_parse_md5_keys,
1644 };
1645 #endif
1646
1647 /* NOTE: A lot of things set to zero explicitly by call to
1648  *       sk_alloc() so need not be done here.
1649  */
1650 static int tcp_v6_init_sock(struct sock *sk)
1651 {
1652         struct inet_connection_sock *icsk = inet_csk(sk);
1653
1654         tcp_init_sock(sk);
1655
1656         icsk->icsk_af_ops = &ipv6_specific;
1657
1658 #ifdef CONFIG_TCP_MD5SIG
1659         tcp_sk(sk)->af_specific = &tcp_sock_ipv6_specific;
1660 #endif
1661
1662         return 0;
1663 }
1664
1665 static void tcp_v6_destroy_sock(struct sock *sk)
1666 {
1667         tcp_v4_destroy_sock(sk);
1668         inet6_destroy_sock(sk);
1669 }
1670
1671 #ifdef CONFIG_PROC_FS
1672 /* Proc filesystem TCPv6 sock list dumping. */
1673 static void get_openreq6(struct seq_file *seq,
1674                          const struct request_sock *req, int i)
1675 {
1676         long ttd = req->rsk_timer.expires - jiffies;
1677         const struct in6_addr *src = &inet_rsk(req)->ir_v6_loc_addr;
1678         const struct in6_addr *dest = &inet_rsk(req)->ir_v6_rmt_addr;
1679
1680         if (ttd < 0)
1681                 ttd = 0;
1682
1683         seq_printf(seq,
1684                    "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
1685                    "%02X %08X:%08X %02X:%08lX %08X %5u %8d %d %d %pK\n",
1686                    i,
1687                    src->s6_addr32[0], src->s6_addr32[1],
1688                    src->s6_addr32[2], src->s6_addr32[3],
1689                    inet_rsk(req)->ir_num,
1690                    dest->s6_addr32[0], dest->s6_addr32[1],
1691                    dest->s6_addr32[2], dest->s6_addr32[3],
1692                    ntohs(inet_rsk(req)->ir_rmt_port),
1693                    TCP_SYN_RECV,
1694                    0, 0, /* could print option size, but that is af dependent. */
1695                    1,   /* timers active (only the expire timer) */
1696                    jiffies_to_clock_t(ttd),
1697                    req->num_timeout,
1698                    from_kuid_munged(seq_user_ns(seq),
1699                                     sock_i_uid(req->rsk_listener)),
1700                    0,  /* non standard timer */
1701                    0, /* open_requests have no inode */
1702                    0, req);
1703 }
1704
1705 static void get_tcp6_sock(struct seq_file *seq, struct sock *sp, int i)
1706 {
1707         const struct in6_addr *dest, *src;
1708         __u16 destp, srcp;
1709         int timer_active;
1710         unsigned long timer_expires;
1711         const struct inet_sock *inet = inet_sk(sp);
1712         const struct tcp_sock *tp = tcp_sk(sp);
1713         const struct inet_connection_sock *icsk = inet_csk(sp);
1714         const struct fastopen_queue *fastopenq = &icsk->icsk_accept_queue.fastopenq;
1715         int rx_queue;
1716         int state;
1717
1718         dest  = &sp->sk_v6_daddr;
1719         src   = &sp->sk_v6_rcv_saddr;
1720         destp = ntohs(inet->inet_dport);
1721         srcp  = ntohs(inet->inet_sport);
1722
1723         if (icsk->icsk_pending == ICSK_TIME_RETRANS ||
1724             icsk->icsk_pending == ICSK_TIME_EARLY_RETRANS ||
1725             icsk->icsk_pending == ICSK_TIME_LOSS_PROBE) {
1726                 timer_active    = 1;
1727                 timer_expires   = icsk->icsk_timeout;
1728         } else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
1729                 timer_active    = 4;
1730                 timer_expires   = icsk->icsk_timeout;
1731         } else if (timer_pending(&sp->sk_timer)) {
1732                 timer_active    = 2;
1733                 timer_expires   = sp->sk_timer.expires;
1734         } else {
1735                 timer_active    = 0;
1736                 timer_expires = jiffies;
1737         }
1738
1739         state = sk_state_load(sp);
1740         if (state == TCP_LISTEN)
1741                 rx_queue = sp->sk_ack_backlog;
1742         else
1743                 /* Because we don't lock the socket,
1744                  * we might find a transient negative value.
1745                  */
1746                 rx_queue = max_t(int, tp->rcv_nxt - tp->copied_seq, 0);
1747
1748         seq_printf(seq,
1749                    "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
1750                    "%02X %08X:%08X %02X:%08lX %08X %5u %8d %lu %d %pK %lu %lu %u %u %d\n",
1751                    i,
1752                    src->s6_addr32[0], src->s6_addr32[1],
1753                    src->s6_addr32[2], src->s6_addr32[3], srcp,
1754                    dest->s6_addr32[0], dest->s6_addr32[1],
1755                    dest->s6_addr32[2], dest->s6_addr32[3], destp,
1756                    state,
1757                    tp->write_seq - tp->snd_una,
1758                    rx_queue,
1759                    timer_active,
1760                    jiffies_delta_to_clock_t(timer_expires - jiffies),
1761                    icsk->icsk_retransmits,
1762                    from_kuid_munged(seq_user_ns(seq), sock_i_uid(sp)),
1763                    icsk->icsk_probes_out,
1764                    sock_i_ino(sp),
1765                    atomic_read(&sp->sk_refcnt), sp,
1766                    jiffies_to_clock_t(icsk->icsk_rto),
1767                    jiffies_to_clock_t(icsk->icsk_ack.ato),
1768                    (icsk->icsk_ack.quick << 1) | icsk->icsk_ack.pingpong,
1769                    tp->snd_cwnd,
1770                    state == TCP_LISTEN ?
1771                         fastopenq->max_qlen :
1772                         (tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh)
1773                    );
1774 }
1775
1776 static void get_timewait6_sock(struct seq_file *seq,
1777                                struct inet_timewait_sock *tw, int i)
1778 {
1779         long delta = tw->tw_timer.expires - jiffies;
1780         const struct in6_addr *dest, *src;
1781         __u16 destp, srcp;
1782
1783         dest = &tw->tw_v6_daddr;
1784         src  = &tw->tw_v6_rcv_saddr;
1785         destp = ntohs(tw->tw_dport);
1786         srcp  = ntohs(tw->tw_sport);
1787
1788         seq_printf(seq,
1789                    "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
1790                    "%02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK\n",
1791                    i,
1792                    src->s6_addr32[0], src->s6_addr32[1],
1793                    src->s6_addr32[2], src->s6_addr32[3], srcp,
1794                    dest->s6_addr32[0], dest->s6_addr32[1],
1795                    dest->s6_addr32[2], dest->s6_addr32[3], destp,
1796                    tw->tw_substate, 0, 0,
1797                    3, jiffies_delta_to_clock_t(delta), 0, 0, 0, 0,
1798                    atomic_read(&tw->tw_refcnt), tw);
1799 }
1800
1801 static int tcp6_seq_show(struct seq_file *seq, void *v)
1802 {
1803         struct tcp_iter_state *st;
1804         struct sock *sk = v;
1805
1806         if (v == SEQ_START_TOKEN) {
1807                 seq_puts(seq,
1808                          "  sl  "
1809                          "local_address                         "
1810                          "remote_address                        "
1811                          "st tx_queue rx_queue tr tm->when retrnsmt"
1812                          "   uid  timeout inode\n");
1813                 goto out;
1814         }
1815         st = seq->private;
1816
1817         if (sk->sk_state == TCP_TIME_WAIT)
1818                 get_timewait6_sock(seq, v, st->num);
1819         else if (sk->sk_state == TCP_NEW_SYN_RECV)
1820                 get_openreq6(seq, v, st->num);
1821         else
1822                 get_tcp6_sock(seq, v, st->num);
1823 out:
1824         return 0;
1825 }
1826
1827 static const struct file_operations tcp6_afinfo_seq_fops = {
1828         .owner   = THIS_MODULE,
1829         .open    = tcp_seq_open,
1830         .read    = seq_read,
1831         .llseek  = seq_lseek,
1832         .release = seq_release_net
1833 };
1834
1835 static struct tcp_seq_afinfo tcp6_seq_afinfo = {
1836         .name           = "tcp6",
1837         .family         = AF_INET6,
1838         .seq_fops       = &tcp6_afinfo_seq_fops,
1839         .seq_ops        = {
1840                 .show           = tcp6_seq_show,
1841         },
1842 };
1843
1844 int __net_init tcp6_proc_init(struct net *net)
1845 {
1846         return tcp_proc_register(net, &tcp6_seq_afinfo);
1847 }
1848
1849 void tcp6_proc_exit(struct net *net)
1850 {
1851         tcp_proc_unregister(net, &tcp6_seq_afinfo);
1852 }
1853 #endif
1854
1855 static void tcp_v6_clear_sk(struct sock *sk, int size)
1856 {
1857         struct inet_sock *inet = inet_sk(sk);
1858
1859         /* we do not want to clear pinet6 field, because of RCU lookups */
1860         sk_prot_clear_nulls(sk, offsetof(struct inet_sock, pinet6));
1861
1862         size -= offsetof(struct inet_sock, pinet6) + sizeof(inet->pinet6);
1863         memset(&inet->pinet6 + 1, 0, size);
1864 }
1865
1866 struct proto tcpv6_prot = {
1867         .name                   = "TCPv6",
1868         .owner                  = THIS_MODULE,
1869         .close                  = tcp_close,
1870         .connect                = tcp_v6_connect,
1871         .disconnect             = tcp_disconnect,
1872         .accept                 = inet_csk_accept,
1873         .ioctl                  = tcp_ioctl,
1874         .init                   = tcp_v6_init_sock,
1875         .destroy                = tcp_v6_destroy_sock,
1876         .shutdown               = tcp_shutdown,
1877         .setsockopt             = tcp_setsockopt,
1878         .getsockopt             = tcp_getsockopt,
1879         .recvmsg                = tcp_recvmsg,
1880         .sendmsg                = tcp_sendmsg,
1881         .sendpage               = tcp_sendpage,
1882         .backlog_rcv            = tcp_v6_do_rcv,
1883         .release_cb             = tcp_release_cb,
1884         .hash                   = inet_hash,
1885         .unhash                 = inet_unhash,
1886         .get_port               = inet_csk_get_port,
1887         .enter_memory_pressure  = tcp_enter_memory_pressure,
1888         .stream_memory_free     = tcp_stream_memory_free,
1889         .sockets_allocated      = &tcp_sockets_allocated,
1890         .memory_allocated       = &tcp_memory_allocated,
1891         .memory_pressure        = &tcp_memory_pressure,
1892         .orphan_count           = &tcp_orphan_count,
1893         .sysctl_mem             = sysctl_tcp_mem,
1894         .sysctl_wmem            = sysctl_tcp_wmem,
1895         .sysctl_rmem            = sysctl_tcp_rmem,
1896         .max_header             = MAX_TCP_HEADER,
1897         .obj_size               = sizeof(struct tcp6_sock),
1898         .slab_flags             = SLAB_DESTROY_BY_RCU,
1899         .twsk_prot              = &tcp6_timewait_sock_ops,
1900         .rsk_prot               = &tcp6_request_sock_ops,
1901         .h.hashinfo             = &tcp_hashinfo,
1902         .no_autobind            = true,
1903 #ifdef CONFIG_COMPAT
1904         .compat_setsockopt      = compat_tcp_setsockopt,
1905         .compat_getsockopt      = compat_tcp_getsockopt,
1906 #endif
1907 #ifdef CONFIG_MEMCG_KMEM
1908         .proto_cgroup           = tcp_proto_cgroup,
1909 #endif
1910         .clear_sk               = tcp_v6_clear_sk,
1911         .diag_destroy           = tcp_abort,
1912 };
1913
1914 static const struct inet6_protocol tcpv6_protocol = {
1915         .early_demux    =       tcp_v6_early_demux,
1916         .handler        =       tcp_v6_rcv,
1917         .err_handler    =       tcp_v6_err,
1918         .flags          =       INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
1919 };
1920
1921 static struct inet_protosw tcpv6_protosw = {
1922         .type           =       SOCK_STREAM,
1923         .protocol       =       IPPROTO_TCP,
1924         .prot           =       &tcpv6_prot,
1925         .ops            =       &inet6_stream_ops,
1926         .flags          =       INET_PROTOSW_PERMANENT |
1927                                 INET_PROTOSW_ICSK,
1928 };
1929
1930 static int __net_init tcpv6_net_init(struct net *net)
1931 {
1932         return inet_ctl_sock_create(&net->ipv6.tcp_sk, PF_INET6,
1933                                     SOCK_RAW, IPPROTO_TCP, net);
1934 }
1935
1936 static void __net_exit tcpv6_net_exit(struct net *net)
1937 {
1938         inet_ctl_sock_destroy(net->ipv6.tcp_sk);
1939 }
1940
1941 static void __net_exit tcpv6_net_exit_batch(struct list_head *net_exit_list)
1942 {
1943         inet_twsk_purge(&tcp_hashinfo, &tcp_death_row, AF_INET6);
1944 }
1945
1946 static struct pernet_operations tcpv6_net_ops = {
1947         .init       = tcpv6_net_init,
1948         .exit       = tcpv6_net_exit,
1949         .exit_batch = tcpv6_net_exit_batch,
1950 };
1951
1952 int __init tcpv6_init(void)
1953 {
1954         int ret;
1955
1956         ret = inet6_add_protocol(&tcpv6_protocol, IPPROTO_TCP);
1957         if (ret)
1958                 goto out;
1959
1960         /* register inet6 protocol */
1961         ret = inet6_register_protosw(&tcpv6_protosw);
1962         if (ret)
1963                 goto out_tcpv6_protocol;
1964
1965         ret = register_pernet_subsys(&tcpv6_net_ops);
1966         if (ret)
1967                 goto out_tcpv6_protosw;
1968 out:
1969         return ret;
1970
1971 out_tcpv6_protosw:
1972         inet6_unregister_protosw(&tcpv6_protosw);
1973 out_tcpv6_protocol:
1974         inet6_del_protocol(&tcpv6_protocol, IPPROTO_TCP);
1975         goto out;
1976 }
1977
1978 void tcpv6_exit(void)
1979 {
1980         unregister_pernet_subsys(&tcpv6_net_ops);
1981         inet6_unregister_protosw(&tcpv6_protosw);
1982         inet6_del_protocol(&tcpv6_protocol, IPPROTO_TCP);
1983 }