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                 if (!sock_owned_by_user(sk)) {
 381                         struct dst_entry *dst = __sk_dst_check(sk, np->dst_cookie);
 382
 383                         if (dst)
 384                                 dst->ops->redirect(dst, sk, skb);
 385                 }
 386                 goto out;
 387         }
 388
 389         if (type == ICMPV6_PKT_TOOBIG) {
 390                 /* We are not interested in TCP_LISTEN and open_requests
 391                  * (SYN-ACKs send out by Linux are always <576bytes so
 392                  * they should go through unfragmented).
 393                  */
 394                 if (sk->sk_state == TCP_LISTEN)
 395                         goto out;
 396
 397                 if (!ip6_sk_accept_pmtu(sk))
 398                         goto out;
 399
 400                 tp->mtu_info = ntohl(info);
 401                 if (!sock_owned_by_user(sk))
 402                         tcp_v6_mtu_reduced(sk);
 403                 else if (!test_and_set_bit(TCP_MTU_REDUCED_DEFERRED,
 404                                            &tp->tsq_flags))
 405                         sock_hold(sk);
 406                 goto out;
 407         }
 408
 409
 410         /* Might be for an request_sock */
 411         switch (sk->sk_state) {
 412         case TCP_SYN_SENT:
 413         case TCP_SYN_RECV:
 414                 /* Only in fast or simultaneous open. If a fast open socket is
 415                  * is already accepted it is treated as a connected one below.
 416                  */
 417                 if (fastopen && !fastopen->sk)
 418                         break;
 419
 420                 if (!sock_owned_by_user(sk)) {
 421                         sk->sk_err = err;
 422                         sk->sk_error_report(sk);                /* Wake people up to see the error (see connect in sock.c) */
 423
 424                         tcp_done(sk);
 425                 } else
 426                         sk->sk_err_soft = err;
 427                 goto out;
 428         }
 429
 430         if (!sock_owned_by_user(sk) && np->recverr) {
 431                 sk->sk_err = err;
 432                 sk->sk_error_report(sk);
 433         } else
 434                 sk->sk_err_soft = err;
 435
 436 out:
 437         bh_unlock_sock(sk);
 438         sock_put(sk);
 439 }
 440
 441
 442 static int tcp_v6_send_synack(const struct sock *sk, struct dst_entry *dst,
 443                               struct flowi *fl,
 444                               struct request_sock *req,
 445                               struct tcp_fastopen_cookie *foc,
 446                               bool attach_req)
 447 {
 448         struct inet_request_sock *ireq = inet_rsk(req);
 449         struct ipv6_pinfo *np = inet6_sk(sk);
 450         struct flowi6 *fl6 = &fl->u.ip6;
 451         struct sk_buff *skb;
 452         int err = -ENOMEM;
 453
 454         /* First, grab a route. */
 455         if (!dst && (dst = inet6_csk_route_req(sk, fl6, req,
 456                                                IPPROTO_TCP)) == NULL)
 457                 goto done;
 458
 459         skb = tcp_make_synack(sk, dst, req, foc, attach_req);
 460
 461         if (skb) {
 462                 __tcp_v6_send_check(skb, &ireq->ir_v6_loc_addr,
 463                                     &ireq->ir_v6_rmt_addr);
 464
 465                 fl6->daddr = ireq->ir_v6_rmt_addr;
 466                 if (np->repflow && ireq->pktopts)
 467                         fl6->flowlabel = ip6_flowlabel(ipv6_hdr(ireq->pktopts));
 468
 469                 rcu_read_lock();
 470                 err = ip6_xmit(sk, skb, fl6, rcu_dereference(np->opt),
 471                                np->tclass);
 472                 rcu_read_unlock();
 473                 err = net_xmit_eval(err);
 474         }
 475
 476 done:
 477         return err;
 478 }
 479
 480
 481 static void tcp_v6_reqsk_destructor(struct request_sock *req)
 482 {
 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_pseudoheader(struct tcp_md5sig_pool *hp,
 534                                         const struct in6_addr *daddr,
 535                                         const struct in6_addr *saddr, int nbytes)
 536 {
 537         struct tcp6_pseudohdr *bp;
 538         struct scatterlist sg;
 539
 540         bp = &hp->md5_blk.ip6;
 541         /* 1. TCP pseudo-header (RFC2460) */
 542         bp->saddr = *saddr;
 543         bp->daddr = *daddr;
 544         bp->protocol = cpu_to_be32(IPPROTO_TCP);
 545         bp->len = cpu_to_be32(nbytes);
 546
 547         sg_init_one(&sg, bp, sizeof(*bp));
 548         return crypto_hash_update(&hp->md5_desc, &sg, sizeof(*bp));
 549 }
 550
 551 static int tcp_v6_md5_hash_hdr(char *md5_hash, struct tcp_md5sig_key *key,
 552                                const struct in6_addr *daddr, struct in6_addr *saddr,
 553                                const struct tcphdr *th)
 554 {
 555         struct tcp_md5sig_pool *hp;
 556         struct hash_desc *desc;
 557
 558         hp = tcp_get_md5sig_pool();
 559         if (!hp)
 560                 goto clear_hash_noput;
 561         desc = &hp->md5_desc;
 562
 563         if (crypto_hash_init(desc))
 564                 goto clear_hash;
 565         if (tcp_v6_md5_hash_pseudoheader(hp, daddr, saddr, th->doff << 2))
 566                 goto clear_hash;
 567         if (tcp_md5_hash_header(hp, th))
 568                 goto clear_hash;
 569         if (tcp_md5_hash_key(hp, key))
 570                 goto clear_hash;
 571         if (crypto_hash_final(desc, md5_hash))
 572                 goto clear_hash;
 573
 574         tcp_put_md5sig_pool();
 575         return 0;
 576
 577 clear_hash:
 578         tcp_put_md5sig_pool();
 579 clear_hash_noput:
 580         memset(md5_hash, 0, 16);
 581         return 1;
 582 }
 583
 584 static int tcp_v6_md5_hash_skb(char *md5_hash,
 585                                const struct tcp_md5sig_key *key,
 586                                const struct sock *sk,
 587                                const struct sk_buff *skb)
 588 {
 589         const struct in6_addr *saddr, *daddr;
 590         struct tcp_md5sig_pool *hp;
 591         struct hash_desc *desc;
 592         const struct tcphdr *th = tcp_hdr(skb);
 593
 594         if (sk) { /* valid for establish/request sockets */
 595                 saddr = &sk->sk_v6_rcv_saddr;
 596                 daddr = &sk->sk_v6_daddr;
 597         } else {
 598                 const struct ipv6hdr *ip6h = ipv6_hdr(skb);
 599                 saddr = &ip6h->saddr;
 600                 daddr = &ip6h->daddr;
 601         }
 602
 603         hp = tcp_get_md5sig_pool();
 604         if (!hp)
 605                 goto clear_hash_noput;
 606         desc = &hp->md5_desc;
 607
 608         if (crypto_hash_init(desc))
 609                 goto clear_hash;
 610
 611         if (tcp_v6_md5_hash_pseudoheader(hp, daddr, saddr, skb->len))
 612                 goto clear_hash;
 613         if (tcp_md5_hash_header(hp, th))
 614                 goto clear_hash;
 615         if (tcp_md5_hash_skb_data(hp, skb, th->doff << 2))
 616                 goto clear_hash;
 617         if (tcp_md5_hash_key(hp, key))
 618                 goto clear_hash;
 619         if (crypto_hash_final(desc, md5_hash))
 620                 goto clear_hash;
 621
 622         tcp_put_md5sig_pool();
 623         return 0;
 624
 625 clear_hash:
 626         tcp_put_md5sig_pool();
 627 clear_hash_noput:
 628         memset(md5_hash, 0, 16);
 629         return 1;
 630 }
 631
 632 #endif
 633
 634 static bool tcp_v6_inbound_md5_hash(const struct sock *sk,
 635                                     const struct sk_buff *skb)
 636 {
 637 #ifdef CONFIG_TCP_MD5SIG
 638         const __u8 *hash_location = NULL;
 639         struct tcp_md5sig_key *hash_expected;
 640         const struct ipv6hdr *ip6h = ipv6_hdr(skb);
 641         const struct tcphdr *th = tcp_hdr(skb);
 642         int genhash;
 643         u8 newhash[16];
 644
 645         hash_expected = tcp_v6_md5_do_lookup(sk, &ip6h->saddr);
 646         hash_location = tcp_parse_md5sig_option(th);
 647
 648         /* We've parsed the options - do we have a hash? */
 649         if (!hash_expected && !hash_location)
 650                 return false;
 651
 652         if (hash_expected && !hash_location) {
 653                 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5NOTFOUND);
 654                 return true;
 655         }
 656
 657         if (!hash_expected && hash_location) {
 658                 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5UNEXPECTED);
 659                 return true;
 660         }
 661
 662         /* check the signature */
 663         genhash = tcp_v6_md5_hash_skb(newhash,
 664                                       hash_expected,
 665                                       NULL, skb);
 666
 667         if (genhash || memcmp(hash_location, newhash, 16) != 0) {
 668                 net_info_ratelimited("MD5 Hash %s for [%pI6c]:%u->[%pI6c]:%u\n",
 669                                      genhash ? "failed" : "mismatch",
 670                                      &ip6h->saddr, ntohs(th->source),
 671                                      &ip6h->daddr, ntohs(th->dest));
 672                 return true;
 673         }
 674 #endif
 675         return false;
 676 }
 677
 678 static void tcp_v6_init_req(struct request_sock *req,
 679                             const struct sock *sk_listener,
 680                             struct sk_buff *skb)
 681 {
 682         struct inet_request_sock *ireq = inet_rsk(req);
 683         const struct ipv6_pinfo *np = inet6_sk(sk_listener);
 684
 685         ireq->ir_v6_rmt_addr = ipv6_hdr(skb)->saddr;
 686         ireq->ir_v6_loc_addr = ipv6_hdr(skb)->daddr;
 687
 688         /* So that link locals have meaning */
 689         if (!sk_listener->sk_bound_dev_if &&
 690             ipv6_addr_type(&ireq->ir_v6_rmt_addr) & IPV6_ADDR_LINKLOCAL)
 691                 ireq->ir_iif = tcp_v6_iif(skb);
 692
 693         if (!TCP_SKB_CB(skb)->tcp_tw_isn &&
 694             (ipv6_opt_accepted(sk_listener, skb, &TCP_SKB_CB(skb)->header.h6) ||
 695              np->rxopt.bits.rxinfo ||
 696              np->rxopt.bits.rxoinfo || np->rxopt.bits.rxhlim ||
 697              np->rxopt.bits.rxohlim || np->repflow)) {
 698                 atomic_inc(&skb->users);
 699                 ireq->pktopts = skb;
 700         }
 701 }
 702
 703 static struct dst_entry *tcp_v6_route_req(const struct sock *sk,
 704                                           struct flowi *fl,
 705                                           const struct request_sock *req,
 706                                           bool *strict)
 707 {
 708         if (strict)
 709                 *strict = true;
 710         return inet6_csk_route_req(sk, &fl->u.ip6, req, IPPROTO_TCP);
 711 }
 712
 713 struct request_sock_ops tcp6_request_sock_ops __read_mostly = {
 714         .family         =       AF_INET6,
 715         .obj_size       =       sizeof(struct tcp6_request_sock),
 716         .rtx_syn_ack    =       tcp_rtx_synack,
 717         .send_ack       =       tcp_v6_reqsk_send_ack,
 718         .destructor     =       tcp_v6_reqsk_destructor,
 719         .send_reset     =       tcp_v6_send_reset,
 720         .syn_ack_timeout =      tcp_syn_ack_timeout,
 721 };
 722
 723 static const struct tcp_request_sock_ops tcp_request_sock_ipv6_ops = {
 724         .mss_clamp      =       IPV6_MIN_MTU - sizeof(struct tcphdr) -
 725                                 sizeof(struct ipv6hdr),
 726 #ifdef CONFIG_TCP_MD5SIG
 727         .req_md5_lookup =       tcp_v6_md5_lookup,
 728         .calc_md5_hash  =       tcp_v6_md5_hash_skb,
 729 #endif
 730         .init_req       =       tcp_v6_init_req,
 731 #ifdef CONFIG_SYN_COOKIES
 732         .cookie_init_seq =      cookie_v6_init_sequence,
 733 #endif
 734         .route_req      =       tcp_v6_route_req,
 735         .init_seq       =       tcp_v6_init_sequence,
 736         .send_synack    =       tcp_v6_send_synack,
 737 };
 738
 739 static void tcp_v6_send_response(const struct sock *sk, struct sk_buff *skb, u32 seq,
 740                                  u32 ack, u32 win, u32 tsval, u32 tsecr,
 741                                  int oif, struct tcp_md5sig_key *key, int rst,
 742                                  u8 tclass, u32 label)
 743 {
 744         const struct tcphdr *th = tcp_hdr(skb);
 745         struct tcphdr *t1;
 746         struct sk_buff *buff;
 747         struct flowi6 fl6;
 748         struct net *net = sk ? sock_net(sk) : dev_net(skb_dst(skb)->dev);
 749         struct sock *ctl_sk = net->ipv6.tcp_sk;
 750         unsigned int tot_len = sizeof(struct tcphdr);
 751         struct dst_entry *dst;
 752         __be32 *topt;
 753
 754         if (tsecr)
 755                 tot_len += TCPOLEN_TSTAMP_ALIGNED;
 756 #ifdef CONFIG_TCP_MD5SIG
 757         if (key)
 758                 tot_len += TCPOLEN_MD5SIG_ALIGNED;
 759 #endif
 760
 761         buff = alloc_skb(MAX_HEADER + sizeof(struct ipv6hdr) + tot_len,
 762                          GFP_ATOMIC);
 763         if (!buff)
 764                 return;
 765
 766         skb_reserve(buff, MAX_HEADER + sizeof(struct ipv6hdr) + tot_len);
 767
 768         t1 = (struct tcphdr *) skb_push(buff, tot_len);
 769         skb_reset_transport_header(buff);
 770
 771         /* Swap the send and the receive. */
 772         memset(t1, 0, sizeof(*t1));
 773         t1->dest = th->source;
 774         t1->source = th->dest;
 775         t1->doff = tot_len / 4;
 776         t1->seq = htonl(seq);
 777         t1->ack_seq = htonl(ack);
 778         t1->ack = !rst || !th->ack;
 779         t1->rst = rst;
 780         t1->window = htons(win);
 781
 782         topt = (__be32 *)(t1 + 1);
 783
 784         if (tsecr) {
 785                 *topt++ = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
 786                                 (TCPOPT_TIMESTAMP << 8) | TCPOLEN_TIMESTAMP);
 787                 *topt++ = htonl(tsval);
 788                 *topt++ = htonl(tsecr);
 789         }
 790
 791 #ifdef CONFIG_TCP_MD5SIG
 792         if (key) {
 793                 *topt++ = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
 794                                 (TCPOPT_MD5SIG << 8) | TCPOLEN_MD5SIG);
 795                 tcp_v6_md5_hash_hdr((__u8 *)topt, key,
 796                                     &ipv6_hdr(skb)->saddr,
 797                                     &ipv6_hdr(skb)->daddr, t1);
 798         }
 799 #endif
 800
 801         memset(&fl6, 0, sizeof(fl6));
 802         fl6.daddr = ipv6_hdr(skb)->saddr;
 803         fl6.saddr = ipv6_hdr(skb)->daddr;
 804         fl6.flowlabel = label;
 805
 806         buff->ip_summed = CHECKSUM_PARTIAL;
 807         buff->csum = 0;
 808
 809         __tcp_v6_send_check(buff, &fl6.saddr, &fl6.daddr);
 810
 811         fl6.flowi6_proto = IPPROTO_TCP;
 812         if (rt6_need_strict(&fl6.daddr) && !oif)
 813                 fl6.flowi6_oif = tcp_v6_iif(skb);
 814         else
 815                 fl6.flowi6_oif = oif;
 816         fl6.flowi6_mark = IP6_REPLY_MARK(net, skb->mark);
 817         fl6.fl6_dport = t1->dest;
 818         fl6.fl6_sport = t1->source;
 819         fl6.flowi6_uid = sock_net_uid(net, sk && sk_fullsock(sk) ? sk : NULL);
 820         security_skb_classify_flow(skb, flowi6_to_flowi(&fl6));
 821
 822         /* Pass a socket to ip6_dst_lookup either it is for RST
 823          * Underlying function will use this to retrieve the network
 824          * namespace
 825          */
 826         dst = ip6_dst_lookup_flow(ctl_sk, &fl6, NULL);
 827         if (!IS_ERR(dst)) {
 828                 skb_dst_set(buff, dst);
 829                 ip6_xmit(ctl_sk, buff, &fl6, NULL, tclass);
 830                 TCP_INC_STATS_BH(net, TCP_MIB_OUTSEGS);
 831                 if (rst)
 832                         TCP_INC_STATS_BH(net, TCP_MIB_OUTRSTS);
 833                 return;
 834         }
 835
 836         kfree_skb(buff);
 837 }
 838
 839 static void tcp_v6_send_reset(const struct sock *sk, struct sk_buff *skb)
 840 {
 841         const struct tcphdr *th = tcp_hdr(skb);
 842         u32 seq = 0, ack_seq = 0;
 843         struct tcp_md5sig_key *key = NULL;
 844 #ifdef CONFIG_TCP_MD5SIG
 845         const __u8 *hash_location = NULL;
 846         struct ipv6hdr *ipv6h = ipv6_hdr(skb);
 847         unsigned char newhash[16];
 848         int genhash;
 849         struct sock *sk1 = NULL;
 850 #endif
 851         int oif;
 852
 853         if (th->rst)
 854                 return;
 855
 856         /* If sk not NULL, it means we did a successful lookup and incoming
 857          * route had to be correct. prequeue might have dropped our dst.
 858          */
 859         if (!sk && !ipv6_unicast_destination(skb))
 860                 return;
 861
 862 #ifdef CONFIG_TCP_MD5SIG
 863         hash_location = tcp_parse_md5sig_option(th);
 864         if (!sk && hash_location) {
 865                 /*
 866                  * active side is lost. Try to find listening socket through
 867                  * source port, and then find md5 key through listening socket.
 868                  * we are not loose security here:
 869                  * Incoming packet is checked with md5 hash with finding key,
 870                  * no RST generated if md5 hash doesn't match.
 871                  */
 872                 sk1 = inet6_lookup_listener(dev_net(skb_dst(skb)->dev),
 873                                            &tcp_hashinfo, &ipv6h->saddr,
 874                                            th->source, &ipv6h->daddr,
 875                                            ntohs(th->source), tcp_v6_iif(skb));
 876                 if (!sk1)
 877                         return;
 878
 879                 rcu_read_lock();
 880                 key = tcp_v6_md5_do_lookup(sk1, &ipv6h->saddr);
 881                 if (!key)
 882                         goto release_sk1;
 883
 884                 genhash = tcp_v6_md5_hash_skb(newhash, key, NULL, skb);
 885                 if (genhash || memcmp(hash_location, newhash, 16) != 0)
 886                         goto release_sk1;
 887         } else {
 888                 key = sk ? tcp_v6_md5_do_lookup(sk, &ipv6h->saddr) : NULL;
 889         }
 890 #endif
 891
 892         if (th->ack)
 893                 seq = ntohl(th->ack_seq);
 894         else
 895                 ack_seq = ntohl(th->seq) + th->syn + th->fin + skb->len -
 896                           (th->doff << 2);
 897
 898         oif = sk ? sk->sk_bound_dev_if : 0;
 899         tcp_v6_send_response(sk, skb, seq, ack_seq, 0, 0, 0, oif, key, 1, 0, 0);
 900
 901 #ifdef CONFIG_TCP_MD5SIG
 902 release_sk1:
 903         if (sk1) {
 904                 rcu_read_unlock();
 905                 sock_put(sk1);
 906         }
 907 #endif
 908 }
 909
 910 static void tcp_v6_send_ack(const struct sock *sk, struct sk_buff *skb, u32 seq,
 911                             u32 ack, u32 win, u32 tsval, u32 tsecr, int oif,
 912                             struct tcp_md5sig_key *key, u8 tclass,
 913                             u32 label)
 914 {
 915         tcp_v6_send_response(sk, skb, seq, ack, win, tsval, tsecr, oif, key, 0,
 916                              tclass, label);
 917 }
 918
 919 static void tcp_v6_timewait_ack(struct sock *sk, struct sk_buff *skb)
 920 {
 921         struct inet_timewait_sock *tw = inet_twsk(sk);
 922         struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
 923
 924         tcp_v6_send_ack(sk, skb, tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
 925                         tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
 926                         tcp_time_stamp + tcptw->tw_ts_offset,
 927                         tcptw->tw_ts_recent, tw->tw_bound_dev_if, tcp_twsk_md5_key(tcptw),
 928                         tw->tw_tclass, cpu_to_be32(tw->tw_flowlabel));
 929
 930         inet_twsk_put(tw);
 931 }
 932
 933 static void tcp_v6_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb,
 934                                   struct request_sock *req)
 935 {
 936         /* sk->sk_state == TCP_LISTEN -> for regular TCP_SYN_RECV
 937          * sk->sk_state == TCP_SYN_RECV -> for Fast Open.
 938          */
 939         /* RFC 7323 2.3
 940          * The window field (SEG.WND) of every outgoing segment, with the
 941          * exception of <SYN> segments, MUST be right-shifted by
 942          * Rcv.Wind.Shift bits:
 943          */
 944         tcp_v6_send_ack(sk, skb, (sk->sk_state == TCP_LISTEN) ?
 945                         tcp_rsk(req)->snt_isn + 1 : tcp_sk(sk)->snd_nxt,
 946                         tcp_rsk(req)->rcv_nxt,
 947                         req->rsk_rcv_wnd >> inet_rsk(req)->rcv_wscale,
 948                         tcp_time_stamp, req->ts_recent, sk->sk_bound_dev_if,
 949                         tcp_v6_md5_do_lookup(sk, &ipv6_hdr(skb)->daddr),
 950                         0, 0);
 951 }
 952
 953
 954 static struct sock *tcp_v6_cookie_check(struct sock *sk, struct sk_buff *skb)
 955 {
 956 #ifdef CONFIG_SYN_COOKIES
 957         const struct tcphdr *th = tcp_hdr(skb);
 958
 959         if (!th->syn)
 960                 sk = cookie_v6_check(sk, skb);
 961 #endif
 962         return sk;
 963 }
 964
 965 static int tcp_v6_conn_request(struct sock *sk, struct sk_buff *skb)
 966 {
 967         if (skb->protocol == htons(ETH_P_IP))
 968                 return tcp_v4_conn_request(sk, skb);
 969
 970         if (!ipv6_unicast_destination(skb))
 971                 goto drop;
 972
 973         return tcp_conn_request(&tcp6_request_sock_ops,
 974                                 &tcp_request_sock_ipv6_ops, sk, skb);
 975
 976 drop:
 977         NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
 978         return 0; /* don't send reset */
 979 }
 980
 981 static void tcp_v6_restore_cb(struct sk_buff *skb)
 982 {
 983         /* We need to move header back to the beginning if xfrm6_policy_check()
 984          * and tcp_v6_fill_cb() are going to be called again.
 985          * ip6_datagram_recv_specific_ctl() also expects IP6CB to be there.
 986          */
 987         memmove(IP6CB(skb), &TCP_SKB_CB(skb)->header.h6,
 988                 sizeof(struct inet6_skb_parm));
 989 }
 990
 991 static struct sock *tcp_v6_syn_recv_sock(const struct sock *sk, struct sk_buff *skb,
 992                                          struct request_sock *req,
 993                                          struct dst_entry *dst,
 994                                          struct request_sock *req_unhash,
 995                                          bool *own_req)
 996 {
 997         struct inet_request_sock *ireq;
 998         struct ipv6_pinfo *newnp;
 999         const struct ipv6_pinfo *np = inet6_sk(sk);
1000         struct ipv6_txoptions *opt;
1001         struct tcp6_sock *newtcp6sk;
1002         struct inet_sock *newinet;
1003         struct tcp_sock *newtp;
1004         struct sock *newsk;
1005 #ifdef CONFIG_TCP_MD5SIG
1006         struct tcp_md5sig_key *key;
1007 #endif
1008         struct flowi6 fl6;
1009
1010         if (skb->protocol == htons(ETH_P_IP)) {
1011                 /*
1012                  *      v6 mapped
1013                  */
1014
1015                 newsk = tcp_v4_syn_recv_sock(sk, skb, req, dst,
1016                                              req_unhash, own_req);
1017
1018                 if (!newsk)
1019                         return NULL;
1020
1021                 newtcp6sk = (struct tcp6_sock *)newsk;
1022                 inet_sk(newsk)->pinet6 = &newtcp6sk->inet6;
1023
1024                 newinet = inet_sk(newsk);
1025                 newnp = inet6_sk(newsk);
1026                 newtp = tcp_sk(newsk);
1027
1028                 memcpy(newnp, np, sizeof(struct ipv6_pinfo));
1029
1030                 newnp->saddr = newsk->sk_v6_rcv_saddr;
1031
1032                 inet_csk(newsk)->icsk_af_ops = &ipv6_mapped;
1033                 newsk->sk_backlog_rcv = tcp_v4_do_rcv;
1034 #ifdef CONFIG_TCP_MD5SIG
1035                 newtp->af_specific = &tcp_sock_ipv6_mapped_specific;
1036 #endif
1037
1038                 newnp->ipv6_ac_list = NULL;
1039                 newnp->ipv6_fl_list = NULL;
1040                 newnp->pktoptions  = NULL;
1041                 newnp->opt         = NULL;
1042                 newnp->mcast_oif   = tcp_v6_iif(skb);
1043                 newnp->mcast_hops  = ipv6_hdr(skb)->hop_limit;
1044                 newnp->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(skb));
1045                 if (np->repflow)
1046                         newnp->flow_label = ip6_flowlabel(ipv6_hdr(skb));
1047
1048                 /*
1049                  * No need to charge this sock to the relevant IPv6 refcnt debug socks count
1050                  * here, tcp_create_openreq_child now does this for us, see the comment in
1051                  * that function for the gory details. -acme
1052                  */
1053
1054                 /* It is tricky place. Until this moment IPv4 tcp
1055                    worked with IPv6 icsk.icsk_af_ops.
1056                    Sync it now.
1057                  */
1058                 tcp_sync_mss(newsk, inet_csk(newsk)->icsk_pmtu_cookie);
1059
1060                 return newsk;
1061         }
1062
1063         ireq = inet_rsk(req);
1064
1065         if (sk_acceptq_is_full(sk))
1066                 goto out_overflow;
1067
1068         if (!dst) {
1069                 dst = inet6_csk_route_req(sk, &fl6, req, IPPROTO_TCP);
1070                 if (!dst)
1071                         goto out;
1072         }
1073
1074         newsk = tcp_create_openreq_child(sk, req, skb);
1075         if (!newsk)
1076                 goto out_nonewsk;
1077
1078         /*
1079          * No need to charge this sock to the relevant IPv6 refcnt debug socks
1080          * count here, tcp_create_openreq_child now does this for us, see the
1081          * comment in that function for the gory details. -acme
1082          */
1083
1084         newsk->sk_gso_type = SKB_GSO_TCPV6;
1085         ip6_dst_store(newsk, dst, NULL, NULL);
1086         inet6_sk_rx_dst_set(newsk, skb);
1087
1088         newtcp6sk = (struct tcp6_sock *)newsk;
1089         inet_sk(newsk)->pinet6 = &newtcp6sk->inet6;
1090
1091         newtp = tcp_sk(newsk);
1092         newinet = inet_sk(newsk);
1093         newnp = inet6_sk(newsk);
1094
1095         memcpy(newnp, np, sizeof(struct ipv6_pinfo));
1096
1097         newsk->sk_v6_daddr = ireq->ir_v6_rmt_addr;
1098         newnp->saddr = ireq->ir_v6_loc_addr;
1099         newsk->sk_v6_rcv_saddr = ireq->ir_v6_loc_addr;
1100         newsk->sk_bound_dev_if = ireq->ir_iif;
1101
1102         /* Now IPv6 options...
1103
1104            First: no IPv4 options.
1105          */
1106         newinet->inet_opt = NULL;
1107         newnp->ipv6_ac_list = NULL;
1108         newnp->ipv6_fl_list = NULL;
1109
1110         /* Clone RX bits */
1111         newnp->rxopt.all = np->rxopt.all;
1112
1113         newnp->pktoptions = NULL;
1114         newnp->opt        = NULL;
1115         newnp->mcast_oif  = tcp_v6_iif(skb);
1116         newnp->mcast_hops = ipv6_hdr(skb)->hop_limit;
1117         newnp->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(skb));
1118         if (np->repflow)
1119                 newnp->flow_label = ip6_flowlabel(ipv6_hdr(skb));
1120
1121         /* Clone native IPv6 options from listening socket (if any)
1122
1123            Yes, keeping reference count would be much more clever,
1124            but we make one more one thing there: reattach optmem
1125            to newsk.
1126          */
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_atomic(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_atomic(sk, GFP_ATOMIC));
1178                         consume_skb(ireq->pktopts);
1179                         ireq->pktopts = NULL;
1180                         if (newnp->pktoptions) {
1181                                 tcp_v6_restore_cb(newnp->pktoptions);
1182                                 skb_set_owner_r(newnp->pktoptions, newsk);
1183                         }
1184                 }
1185         }
1186
1187         return newsk;
1188
1189 out_overflow:
1190         NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
1191 out_nonewsk:
1192         dst_release(dst);
1193 out:
1194         NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
1195         return NULL;
1196 }
1197
1198 /* The socket must have it's spinlock held when we get
1199  * here, unless it is a TCP_LISTEN socket.
1200  *
1201  * We have a potential double-lock case here, so even when
1202  * doing backlog processing we use the BH locking scheme.
1203  * This is because we cannot sleep with the original spinlock
1204  * held.
1205  */
1206 static int tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb)
1207 {
1208         struct ipv6_pinfo *np = inet6_sk(sk);
1209         struct tcp_sock *tp;
1210         struct sk_buff *opt_skb = NULL;
1211
1212         /* Imagine: socket is IPv6. IPv4 packet arrives,
1213            goes to IPv4 receive handler and backlogged.
1214            From backlog it always goes here. Kerboom...
1215            Fortunately, tcp_rcv_established and rcv_established
1216            handle them correctly, but it is not case with
1217            tcp_v6_hnd_req and tcp_v6_send_reset().   --ANK
1218          */
1219
1220         if (skb->protocol == htons(ETH_P_IP))
1221                 return tcp_v4_do_rcv(sk, skb);
1222
1223         if (tcp_filter(sk, skb))
1224                 goto discard;
1225
1226         /*
1227          *      socket locking is here for SMP purposes as backlog rcv
1228          *      is currently called with bh processing disabled.
1229          */
1230
1231         /* Do Stevens' IPV6_PKTOPTIONS.
1232
1233            Yes, guys, it is the only place in our code, where we
1234            may make it not affecting IPv4.
1235            The rest of code is protocol independent,
1236            and I do not like idea to uglify IPv4.
1237
1238            Actually, all the idea behind IPV6_PKTOPTIONS
1239            looks not very well thought. For now we latch
1240            options, received in the last packet, enqueued
1241            by tcp. Feel free to propose better solution.
1242                                                --ANK (980728)
1243          */
1244         if (np->rxopt.all)
1245                 opt_skb = skb_clone(skb, sk_gfp_atomic(sk, GFP_ATOMIC));
1246
1247         if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
1248                 struct dst_entry *dst = sk->sk_rx_dst;
1249
1250                 sock_rps_save_rxhash(sk, skb);
1251                 sk_mark_napi_id(sk, skb);
1252                 if (dst) {
1253                         if (inet_sk(sk)->rx_dst_ifindex != skb->skb_iif ||
1254                             dst->ops->check(dst, np->rx_dst_cookie) == NULL) {
1255                                 dst_release(dst);
1256                                 sk->sk_rx_dst = NULL;
1257                         }
1258                 }
1259
1260                 tcp_rcv_established(sk, skb, tcp_hdr(skb), skb->len);
1261                 if (opt_skb)
1262                         goto ipv6_pktoptions;
1263                 return 0;
1264         }
1265
1266         if (tcp_checksum_complete(skb))
1267                 goto csum_err;
1268
1269         if (sk->sk_state == TCP_LISTEN) {
1270                 struct sock *nsk = tcp_v6_cookie_check(sk, skb);
1271
1272                 if (!nsk)
1273                         goto discard;
1274
1275                 if (nsk != sk) {
1276                         sock_rps_save_rxhash(nsk, skb);
1277                         sk_mark_napi_id(nsk, skb);
1278                         if (tcp_child_process(sk, nsk, skb))
1279                                 goto reset;
1280                         if (opt_skb)
1281                                 __kfree_skb(opt_skb);
1282                         return 0;
1283                 }
1284         } else
1285                 sock_rps_save_rxhash(sk, skb);
1286
1287         if (tcp_rcv_state_process(sk, skb))
1288                 goto reset;
1289         if (opt_skb)
1290                 goto ipv6_pktoptions;
1291         return 0;
1292
1293 reset:
1294         tcp_v6_send_reset(sk, skb);
1295 discard:
1296         if (opt_skb)
1297                 __kfree_skb(opt_skb);
1298         kfree_skb(skb);
1299         return 0;
1300 csum_err:
1301         TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_CSUMERRORS);
1302         TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_INERRS);
1303         goto discard;
1304
1305
1306 ipv6_pktoptions:
1307         /* Do you ask, what is it?
1308
1309            1. skb was enqueued by tcp.
1310            2. skb is added to tail of read queue, rather than out of order.
1311            3. socket is not in passive state.
1312            4. Finally, it really contains options, which user wants to receive.
1313          */
1314         tp = tcp_sk(sk);
1315         if (TCP_SKB_CB(opt_skb)->end_seq == tp->rcv_nxt &&
1316             !((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN))) {
1317                 if (np->rxopt.bits.rxinfo || np->rxopt.bits.rxoinfo)
1318                         np->mcast_oif = tcp_v6_iif(opt_skb);
1319                 if (np->rxopt.bits.rxhlim || np->rxopt.bits.rxohlim)
1320                         np->mcast_hops = ipv6_hdr(opt_skb)->hop_limit;
1321                 if (np->rxopt.bits.rxflow || np->rxopt.bits.rxtclass)
1322                         np->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(opt_skb));
1323                 if (np->repflow)
1324                         np->flow_label = ip6_flowlabel(ipv6_hdr(opt_skb));
1325                 if (ipv6_opt_accepted(sk, opt_skb, &TCP_SKB_CB(opt_skb)->header.h6)) {
1326                         skb_set_owner_r(opt_skb, sk);
1327                         tcp_v6_restore_cb(opt_skb);
1328                         opt_skb = xchg(&np->pktoptions, opt_skb);
1329                 } else {
1330                         __kfree_skb(opt_skb);
1331                         opt_skb = xchg(&np->pktoptions, NULL);
1332                 }
1333         }
1334
1335         kfree_skb(opt_skb);
1336         return 0;
1337 }
1338
1339 static void tcp_v6_fill_cb(struct sk_buff *skb, const struct ipv6hdr *hdr,
1340                            const struct tcphdr *th)
1341 {
1342         /* This is tricky: we move IP6CB at its correct location into
1343          * TCP_SKB_CB(). It must be done after xfrm6_policy_check(), because
1344          * _decode_session6() uses IP6CB().
1345          * barrier() makes sure compiler won't play aliasing games.
1346          */
1347         memmove(&TCP_SKB_CB(skb)->header.h6, IP6CB(skb),
1348                 sizeof(struct inet6_skb_parm));
1349         barrier();
1350
1351         TCP_SKB_CB(skb)->seq = ntohl(th->seq);
1352         TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
1353                                     skb->len - th->doff*4);
1354         TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
1355         TCP_SKB_CB(skb)->tcp_flags = tcp_flag_byte(th);
1356         TCP_SKB_CB(skb)->tcp_tw_isn = 0;
1357         TCP_SKB_CB(skb)->ip_dsfield = ipv6_get_dsfield(hdr);
1358         TCP_SKB_CB(skb)->sacked = 0;
1359 }
1360
1361 static int tcp_v6_rcv(struct sk_buff *skb)
1362 {
1363         const struct tcphdr *th;
1364         const struct ipv6hdr *hdr;
1365         struct sock *sk;
1366         int ret;
1367         struct net *net = dev_net(skb->dev);
1368
1369         if (skb->pkt_type != PACKET_HOST)
1370                 goto discard_it;
1371
1372         /*
1373          *      Count it even if it's bad.
1374          */
1375         TCP_INC_STATS_BH(net, TCP_MIB_INSEGS);
1376
1377         if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
1378                 goto discard_it;
1379
1380         th = tcp_hdr(skb);
1381
1382         if (th->doff < sizeof(struct tcphdr)/4)
1383                 goto bad_packet;
1384         if (!pskb_may_pull(skb, th->doff*4))
1385                 goto discard_it;
1386
1387         if (skb_checksum_init(skb, IPPROTO_TCP, ip6_compute_pseudo))
1388                 goto csum_error;
1389
1390         th = tcp_hdr(skb);
1391         hdr = ipv6_hdr(skb);
1392
1393 lookup:
1394         sk = __inet6_lookup_skb(&tcp_hashinfo, skb, th->source, th->dest,
1395                                 inet6_iif(skb));
1396         if (!sk)
1397                 goto no_tcp_socket;
1398
1399 process:
1400         if (sk->sk_state == TCP_TIME_WAIT)
1401                 goto do_time_wait;
1402
1403         if (sk->sk_state == TCP_NEW_SYN_RECV) {
1404                 struct request_sock *req = inet_reqsk(sk);
1405                 struct sock *nsk;
1406
1407                 sk = req->rsk_listener;
1408                 tcp_v6_fill_cb(skb, hdr, th);
1409                 if (tcp_v6_inbound_md5_hash(sk, skb)) {
1410                         reqsk_put(req);
1411                         goto discard_it;
1412                 }
1413                 if (unlikely(sk->sk_state != TCP_LISTEN)) {
1414                         inet_csk_reqsk_queue_drop_and_put(sk, req);
1415                         goto lookup;
1416                 }
1417                 sock_hold(sk);
1418                 nsk = tcp_check_req(sk, skb, req, false);
1419                 if (!nsk) {
1420                         reqsk_put(req);
1421                         goto discard_and_relse;
1422                 }
1423                 if (nsk == sk) {
1424                         reqsk_put(req);
1425                         tcp_v6_restore_cb(skb);
1426                 } else if (tcp_child_process(sk, nsk, skb)) {
1427                         tcp_v6_send_reset(nsk, skb);
1428                         goto discard_and_relse;
1429                 } else {
1430                         sock_put(sk);
1431                         return 0;
1432                 }
1433         }
1434         if (hdr->hop_limit < inet6_sk(sk)->min_hopcount) {
1435                 NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP);
1436                 goto discard_and_relse;
1437         }
1438
1439         if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb))
1440                 goto discard_and_relse;
1441
1442         tcp_v6_fill_cb(skb, hdr, th);
1443
1444         if (tcp_v6_inbound_md5_hash(sk, skb))
1445                 goto discard_and_relse;
1446
1447         if (tcp_filter(sk, skb))
1448                 goto discard_and_relse;
1449         th = (const struct tcphdr *)skb->data;
1450         hdr = ipv6_hdr(skb);
1451
1452         skb->dev = NULL;
1453
1454         if (sk->sk_state == TCP_LISTEN) {
1455                 ret = tcp_v6_do_rcv(sk, skb);
1456                 goto put_and_return;
1457         }
1458
1459         sk_incoming_cpu_update(sk);
1460
1461         bh_lock_sock_nested(sk);
1462         tcp_sk(sk)->segs_in += max_t(u16, 1, skb_shinfo(skb)->gso_segs);
1463         ret = 0;
1464         if (!sock_owned_by_user(sk)) {
1465                 if (!tcp_prequeue(sk, skb))
1466                         ret = tcp_v6_do_rcv(sk, skb);
1467         } else if (unlikely(sk_add_backlog(sk, skb,
1468                                            sk->sk_rcvbuf + sk->sk_sndbuf))) {
1469                 bh_unlock_sock(sk);
1470                 NET_INC_STATS_BH(net, LINUX_MIB_TCPBACKLOGDROP);
1471                 goto discard_and_relse;
1472         }
1473         bh_unlock_sock(sk);
1474
1475 put_and_return:
1476         sock_put(sk);
1477         return ret ? -1 : 0;
1478
1479 no_tcp_socket:
1480         if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb))
1481                 goto discard_it;
1482
1483         tcp_v6_fill_cb(skb, hdr, th);
1484
1485         if (tcp_checksum_complete(skb)) {
1486 csum_error:
1487                 TCP_INC_STATS_BH(net, TCP_MIB_CSUMERRORS);
1488 bad_packet:
1489                 TCP_INC_STATS_BH(net, TCP_MIB_INERRS);
1490         } else {
1491                 tcp_v6_send_reset(NULL, skb);
1492         }
1493
1494 discard_it:
1495         kfree_skb(skb);
1496         return 0;
1497
1498 discard_and_relse:
1499         sock_put(sk);
1500         goto discard_it;
1501
1502 do_time_wait:
1503         if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
1504                 inet_twsk_put(inet_twsk(sk));
1505                 goto discard_it;
1506         }
1507
1508         tcp_v6_fill_cb(skb, hdr, th);
1509
1510         if (tcp_checksum_complete(skb)) {
1511                 inet_twsk_put(inet_twsk(sk));
1512                 goto csum_error;
1513         }
1514
1515         switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) {
1516         case TCP_TW_SYN:
1517         {
1518                 struct sock *sk2;
1519
1520                 sk2 = inet6_lookup_listener(dev_net(skb->dev), &tcp_hashinfo,
1521                                             &ipv6_hdr(skb)->saddr, th->source,
1522                                             &ipv6_hdr(skb)->daddr,
1523                                             ntohs(th->dest), tcp_v6_iif(skb));
1524                 if (sk2) {
1525                         struct inet_timewait_sock *tw = inet_twsk(sk);
1526                         inet_twsk_deschedule_put(tw);
1527                         sk = sk2;
1528                         tcp_v6_restore_cb(skb);
1529                         goto process;
1530                 }
1531                 /* Fall through to ACK */
1532         }
1533         case TCP_TW_ACK:
1534                 tcp_v6_timewait_ack(sk, skb);
1535                 break;
1536         case TCP_TW_RST:
1537                 tcp_v6_restore_cb(skb);
1538                 goto no_tcp_socket;
1539         case TCP_TW_SUCCESS:
1540                 ;
1541         }
1542         goto discard_it;
1543 }
1544
1545 static void tcp_v6_early_demux(struct sk_buff *skb)
1546 {
1547         const struct ipv6hdr *hdr;
1548         const struct tcphdr *th;
1549         struct sock *sk;
1550
1551         if (skb->pkt_type != PACKET_HOST)
1552                 return;
1553
1554         if (!pskb_may_pull(skb, skb_transport_offset(skb) + sizeof(struct tcphdr)))
1555                 return;
1556
1557         hdr = ipv6_hdr(skb);
1558         th = tcp_hdr(skb);
1559
1560         if (th->doff < sizeof(struct tcphdr) / 4)
1561                 return;
1562
1563         /* Note : We use inet6_iif() here, not tcp_v6_iif() */
1564         sk = __inet6_lookup_established(dev_net(skb->dev), &tcp_hashinfo,
1565                                         &hdr->saddr, th->source,
1566                                         &hdr->daddr, ntohs(th->dest),
1567                                         inet6_iif(skb));
1568         if (sk) {
1569                 skb->sk = sk;
1570                 skb->destructor = sock_edemux;
1571                 if (sk_fullsock(sk)) {
1572                         struct dst_entry *dst = READ_ONCE(sk->sk_rx_dst);
1573
1574                         if (dst)
1575                                 dst = dst_check(dst, inet6_sk(sk)->rx_dst_cookie);
1576                         if (dst &&
1577                             inet_sk(sk)->rx_dst_ifindex == skb->skb_iif)
1578                                 skb_dst_set_noref(skb, dst);
1579                 }
1580         }
1581 }
1582
1583 static struct timewait_sock_ops tcp6_timewait_sock_ops = {
1584         .twsk_obj_size  = sizeof(struct tcp6_timewait_sock),
1585         .twsk_unique    = tcp_twsk_unique,
1586         .twsk_destructor = tcp_twsk_destructor,
1587 };
1588
1589 static const struct inet_connection_sock_af_ops ipv6_specific = {
1590         .queue_xmit        = inet6_csk_xmit,
1591         .send_check        = tcp_v6_send_check,
1592         .rebuild_header    = inet6_sk_rebuild_header,
1593         .sk_rx_dst_set     = inet6_sk_rx_dst_set,
1594         .conn_request      = tcp_v6_conn_request,
1595         .syn_recv_sock     = tcp_v6_syn_recv_sock,
1596         .net_header_len    = sizeof(struct ipv6hdr),
1597         .net_frag_header_len = sizeof(struct frag_hdr),
1598         .setsockopt        = ipv6_setsockopt,
1599         .getsockopt        = ipv6_getsockopt,
1600         .addr2sockaddr     = inet6_csk_addr2sockaddr,
1601         .sockaddr_len      = sizeof(struct sockaddr_in6),
1602         .bind_conflict     = inet6_csk_bind_conflict,
1603 #ifdef CONFIG_COMPAT
1604         .compat_setsockopt = compat_ipv6_setsockopt,
1605         .compat_getsockopt = compat_ipv6_getsockopt,
1606 #endif
1607         .mtu_reduced       = tcp_v6_mtu_reduced,
1608 };
1609
1610 #ifdef CONFIG_TCP_MD5SIG
1611 static const struct tcp_sock_af_ops tcp_sock_ipv6_specific = {
1612         .md5_lookup     =       tcp_v6_md5_lookup,
1613         .calc_md5_hash  =       tcp_v6_md5_hash_skb,
1614         .md5_parse      =       tcp_v6_parse_md5_keys,
1615 };
1616 #endif
1617
1618 /*
1619  *      TCP over IPv4 via INET6 API
1620  */
1621 static const struct inet_connection_sock_af_ops ipv6_mapped = {
1622         .queue_xmit        = ip_queue_xmit,
1623         .send_check        = tcp_v4_send_check,
1624         .rebuild_header    = inet_sk_rebuild_header,
1625         .sk_rx_dst_set     = inet_sk_rx_dst_set,
1626         .conn_request      = tcp_v6_conn_request,
1627         .syn_recv_sock     = tcp_v6_syn_recv_sock,
1628         .net_header_len    = sizeof(struct iphdr),
1629         .setsockopt        = ipv6_setsockopt,
1630         .getsockopt        = ipv6_getsockopt,
1631         .addr2sockaddr     = inet6_csk_addr2sockaddr,
1632         .sockaddr_len      = sizeof(struct sockaddr_in6),
1633         .bind_conflict     = inet6_csk_bind_conflict,
1634 #ifdef CONFIG_COMPAT
1635         .compat_setsockopt = compat_ipv6_setsockopt,
1636         .compat_getsockopt = compat_ipv6_getsockopt,
1637 #endif
1638         .mtu_reduced       = tcp_v4_mtu_reduced,
1639 };
1640
1641 #ifdef CONFIG_TCP_MD5SIG
1642 static const struct tcp_sock_af_ops tcp_sock_ipv6_mapped_specific = {
1643         .md5_lookup     =       tcp_v4_md5_lookup,
1644         .calc_md5_hash  =       tcp_v4_md5_hash_skb,
1645         .md5_parse      =       tcp_v6_parse_md5_keys,
1646 };
1647 #endif
1648
1649 /* NOTE: A lot of things set to zero explicitly by call to
1650  *       sk_alloc() so need not be done here.
1651  */
1652 static int tcp_v6_init_sock(struct sock *sk)
1653 {
1654         struct inet_connection_sock *icsk = inet_csk(sk);
1655
1656         tcp_init_sock(sk);
1657
1658         icsk->icsk_af_ops = &ipv6_specific;
1659
1660 #ifdef CONFIG_TCP_MD5SIG
1661         tcp_sk(sk)->af_specific = &tcp_sock_ipv6_specific;
1662 #endif
1663
1664         return 0;
1665 }
1666
1667 static void tcp_v6_destroy_sock(struct sock *sk)
1668 {
1669         tcp_v4_destroy_sock(sk);
1670         inet6_destroy_sock(sk);
1671 }
1672
1673 #ifdef CONFIG_PROC_FS
1674 /* Proc filesystem TCPv6 sock list dumping. */
1675 static void get_openreq6(struct seq_file *seq,
1676                          const struct request_sock *req, int i)
1677 {
1678         long ttd = req->rsk_timer.expires - jiffies;
1679         const struct in6_addr *src = &inet_rsk(req)->ir_v6_loc_addr;
1680         const struct in6_addr *dest = &inet_rsk(req)->ir_v6_rmt_addr;
1681
1682         if (ttd < 0)
1683                 ttd = 0;
1684
1685         seq_printf(seq,
1686                    "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
1687                    "%02X %08X:%08X %02X:%08lX %08X %5u %8d %d %d %pK\n",
1688                    i,
1689                    src->s6_addr32[0], src->s6_addr32[1],
1690                    src->s6_addr32[2], src->s6_addr32[3],
1691                    inet_rsk(req)->ir_num,
1692                    dest->s6_addr32[0], dest->s6_addr32[1],
1693                    dest->s6_addr32[2], dest->s6_addr32[3],
1694                    ntohs(inet_rsk(req)->ir_rmt_port),
1695                    TCP_SYN_RECV,
1696                    0, 0, /* could print option size, but that is af dependent. */
1697                    1,   /* timers active (only the expire timer) */
1698                    jiffies_to_clock_t(ttd),
1699                    req->num_timeout,
1700                    from_kuid_munged(seq_user_ns(seq),
1701                                     sock_i_uid(req->rsk_listener)),
1702                    0,  /* non standard timer */
1703                    0, /* open_requests have no inode */
1704                    0, req);
1705 }
1706
1707 static void get_tcp6_sock(struct seq_file *seq, struct sock *sp, int i)
1708 {
1709         const struct in6_addr *dest, *src;
1710         __u16 destp, srcp;
1711         int timer_active;
1712         unsigned long timer_expires;
1713         const struct inet_sock *inet = inet_sk(sp);
1714         const struct tcp_sock *tp = tcp_sk(sp);
1715         const struct inet_connection_sock *icsk = inet_csk(sp);
1716         const struct fastopen_queue *fastopenq = &icsk->icsk_accept_queue.fastopenq;
1717         int rx_queue;
1718         int state;
1719
1720         dest  = &sp->sk_v6_daddr;
1721         src   = &sp->sk_v6_rcv_saddr;
1722         destp = ntohs(inet->inet_dport);
1723         srcp  = ntohs(inet->inet_sport);
1724
1725         if (icsk->icsk_pending == ICSK_TIME_RETRANS ||
1726             icsk->icsk_pending == ICSK_TIME_EARLY_RETRANS ||
1727             icsk->icsk_pending == ICSK_TIME_LOSS_PROBE) {
1728                 timer_active    = 1;
1729                 timer_expires   = icsk->icsk_timeout;
1730         } else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
1731                 timer_active    = 4;
1732                 timer_expires   = icsk->icsk_timeout;
1733         } else if (timer_pending(&sp->sk_timer)) {
1734                 timer_active    = 2;
1735                 timer_expires   = sp->sk_timer.expires;
1736         } else {
1737                 timer_active    = 0;
1738                 timer_expires = jiffies;
1739         }
1740
1741         state = sk_state_load(sp);
1742         if (state == TCP_LISTEN)
1743                 rx_queue = sp->sk_ack_backlog;
1744         else
1745                 /* Because we don't lock the socket,
1746                  * we might find a transient negative value.
1747                  */
1748                 rx_queue = max_t(int, tp->rcv_nxt - tp->copied_seq, 0);
1749
1750         seq_printf(seq,
1751                    "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
1752                    "%02X %08X:%08X %02X:%08lX %08X %5u %8d %lu %d %pK %lu %lu %u %u %d\n",
1753                    i,
1754                    src->s6_addr32[0], src->s6_addr32[1],
1755                    src->s6_addr32[2], src->s6_addr32[3], srcp,
1756                    dest->s6_addr32[0], dest->s6_addr32[1],
1757                    dest->s6_addr32[2], dest->s6_addr32[3], destp,
1758                    state,
1759                    tp->write_seq - tp->snd_una,
1760                    rx_queue,
1761                    timer_active,
1762                    jiffies_delta_to_clock_t(timer_expires - jiffies),
1763                    icsk->icsk_retransmits,
1764                    from_kuid_munged(seq_user_ns(seq), sock_i_uid(sp)),
1765                    icsk->icsk_probes_out,
1766                    sock_i_ino(sp),
1767                    atomic_read(&sp->sk_refcnt), sp,
1768                    jiffies_to_clock_t(icsk->icsk_rto),
1769                    jiffies_to_clock_t(icsk->icsk_ack.ato),
1770                    (icsk->icsk_ack.quick << 1) | icsk->icsk_ack.pingpong,
1771                    tp->snd_cwnd,
1772                    state == TCP_LISTEN ?
1773                         fastopenq->max_qlen :
1774                         (tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh)
1775                    );
1776 }
1777
1778 static void get_timewait6_sock(struct seq_file *seq,
1779                                struct inet_timewait_sock *tw, int i)
1780 {
1781         long delta = tw->tw_timer.expires - jiffies;
1782         const struct in6_addr *dest, *src;
1783         __u16 destp, srcp;
1784
1785         dest = &tw->tw_v6_daddr;
1786         src  = &tw->tw_v6_rcv_saddr;
1787         destp = ntohs(tw->tw_dport);
1788         srcp  = ntohs(tw->tw_sport);
1789
1790         seq_printf(seq,
1791                    "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
1792                    "%02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK\n",
1793                    i,
1794                    src->s6_addr32[0], src->s6_addr32[1],
1795                    src->s6_addr32[2], src->s6_addr32[3], srcp,
1796                    dest->s6_addr32[0], dest->s6_addr32[1],
1797                    dest->s6_addr32[2], dest->s6_addr32[3], destp,
1798                    tw->tw_substate, 0, 0,
1799                    3, jiffies_delta_to_clock_t(delta), 0, 0, 0, 0,
1800                    atomic_read(&tw->tw_refcnt), tw);
1801 }
1802
1803 static int tcp6_seq_show(struct seq_file *seq, void *v)
1804 {
1805         struct tcp_iter_state *st;
1806         struct sock *sk = v;
1807
1808         if (v == SEQ_START_TOKEN) {
1809                 seq_puts(seq,
1810                          "  sl  "
1811                          "local_address                         "
1812                          "remote_address                        "
1813                          "st tx_queue rx_queue tr tm->when retrnsmt"
1814                          "   uid  timeout inode\n");
1815                 goto out;
1816         }
1817         st = seq->private;
1818
1819         if (sk->sk_state == TCP_TIME_WAIT)
1820                 get_timewait6_sock(seq, v, st->num);
1821         else if (sk->sk_state == TCP_NEW_SYN_RECV)
1822                 get_openreq6(seq, v, st->num);
1823         else
1824                 get_tcp6_sock(seq, v, st->num);
1825 out:
1826         return 0;
1827 }
1828
1829 static const struct file_operations tcp6_afinfo_seq_fops = {
1830         .owner   = THIS_MODULE,
1831         .open    = tcp_seq_open,
1832         .read    = seq_read,
1833         .llseek  = seq_lseek,
1834         .release = seq_release_net
1835 };
1836
1837 static struct tcp_seq_afinfo tcp6_seq_afinfo = {
1838         .name           = "tcp6",
1839         .family         = AF_INET6,
1840         .seq_fops       = &tcp6_afinfo_seq_fops,
1841         .seq_ops        = {
1842                 .show           = tcp6_seq_show,
1843         },
1844 };
1845
1846 int __net_init tcp6_proc_init(struct net *net)
1847 {
1848         return tcp_proc_register(net, &tcp6_seq_afinfo);
1849 }
1850
1851 void tcp6_proc_exit(struct net *net)
1852 {
1853         tcp_proc_unregister(net, &tcp6_seq_afinfo);
1854 }
1855 #endif
1856
1857 static void tcp_v6_clear_sk(struct sock *sk, int size)
1858 {
1859         struct inet_sock *inet = inet_sk(sk);
1860
1861         /* we do not want to clear pinet6 field, because of RCU lookups */
1862         sk_prot_clear_nulls(sk, offsetof(struct inet_sock, pinet6));
1863
1864         size -= offsetof(struct inet_sock, pinet6) + sizeof(inet->pinet6);
1865         memset(&inet->pinet6 + 1, 0, size);
1866 }
1867
1868 struct proto tcpv6_prot = {
1869         .name                   = "TCPv6",
1870         .owner                  = THIS_MODULE,
1871         .close                  = tcp_close,
1872         .connect                = tcp_v6_connect,
1873         .disconnect             = tcp_disconnect,
1874         .accept                 = inet_csk_accept,
1875         .ioctl                  = tcp_ioctl,
1876         .init                   = tcp_v6_init_sock,
1877         .destroy                = tcp_v6_destroy_sock,
1878         .shutdown               = tcp_shutdown,
1879         .setsockopt             = tcp_setsockopt,
1880         .getsockopt             = tcp_getsockopt,
1881         .recvmsg                = tcp_recvmsg,
1882         .sendmsg                = tcp_sendmsg,
1883         .sendpage               = tcp_sendpage,
1884         .backlog_rcv            = tcp_v6_do_rcv,
1885         .release_cb             = tcp_release_cb,
1886         .hash                   = inet_hash,
1887         .unhash                 = inet_unhash,
1888         .get_port               = inet_csk_get_port,
1889         .enter_memory_pressure  = tcp_enter_memory_pressure,
1890         .stream_memory_free     = tcp_stream_memory_free,
1891         .sockets_allocated      = &tcp_sockets_allocated,
1892         .memory_allocated       = &tcp_memory_allocated,
1893         .memory_pressure        = &tcp_memory_pressure,
1894         .orphan_count           = &tcp_orphan_count,
1895         .sysctl_mem             = sysctl_tcp_mem,
1896         .sysctl_wmem            = sysctl_tcp_wmem,
1897         .sysctl_rmem            = sysctl_tcp_rmem,
1898         .max_header             = MAX_TCP_HEADER,
1899         .obj_size               = sizeof(struct tcp6_sock),
1900         .slab_flags             = SLAB_DESTROY_BY_RCU,
1901         .twsk_prot              = &tcp6_timewait_sock_ops,
1902         .rsk_prot               = &tcp6_request_sock_ops,
1903         .h.hashinfo             = &tcp_hashinfo,
1904         .no_autobind            = true,
1905 #ifdef CONFIG_COMPAT
1906         .compat_setsockopt      = compat_tcp_setsockopt,
1907         .compat_getsockopt      = compat_tcp_getsockopt,
1908 #endif
1909 #ifdef CONFIG_MEMCG_KMEM
1910         .proto_cgroup           = tcp_proto_cgroup,
1911 #endif
1912         .clear_sk               = tcp_v6_clear_sk,
1913         .diag_destroy           = tcp_abort,
1914 };
1915
1916 static const struct inet6_protocol tcpv6_protocol = {
1917         .early_demux    =       tcp_v6_early_demux,
1918         .handler        =       tcp_v6_rcv,
1919         .err_handler    =       tcp_v6_err,
1920         .flags          =       INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
1921 };
1922
1923 static struct inet_protosw tcpv6_protosw = {
1924         .type           =       SOCK_STREAM,
1925         .protocol       =       IPPROTO_TCP,
1926         .prot           =       &tcpv6_prot,
1927         .ops            =       &inet6_stream_ops,
1928         .flags          =       INET_PROTOSW_PERMANENT |
1929                                 INET_PROTOSW_ICSK,
1930 };
1931
1932 static int __net_init tcpv6_net_init(struct net *net)
1933 {
1934         return inet_ctl_sock_create(&net->ipv6.tcp_sk, PF_INET6,
1935                                     SOCK_RAW, IPPROTO_TCP, net);
1936 }
1937
1938 static void __net_exit tcpv6_net_exit(struct net *net)
1939 {
1940         inet_ctl_sock_destroy(net->ipv6.tcp_sk);
1941 }
1942
1943 static void __net_exit tcpv6_net_exit_batch(struct list_head *net_exit_list)
1944 {
1945         inet_twsk_purge(&tcp_hashinfo, &tcp_death_row, AF_INET6);
1946 }
1947
1948 static struct pernet_operations tcpv6_net_ops = {
1949         .init       = tcpv6_net_init,
1950         .exit       = tcpv6_net_exit,
1951         .exit_batch = tcpv6_net_exit_batch,
1952 };
1953
1954 int __init tcpv6_init(void)
1955 {
1956         int ret;
1957
1958         ret = inet6_add_protocol(&tcpv6_protocol, IPPROTO_TCP);
1959         if (ret)
1960                 goto out;
1961
1962         /* register inet6 protocol */
1963         ret = inet6_register_protosw(&tcpv6_protosw);
1964         if (ret)
1965                 goto out_tcpv6_protocol;
1966
1967         ret = register_pernet_subsys(&tcpv6_net_ops);
1968         if (ret)
1969                 goto out_tcpv6_protosw;
1970 out:
1971         return ret;
1972
1973 out_tcpv6_protosw:
1974         inet6_unregister_protosw(&tcpv6_protosw);
1975 out_tcpv6_protocol:
1976         inet6_del_protocol(&tcpv6_protocol, IPPROTO_TCP);
1977         goto out;
1978 }
1979
1980 void tcpv6_exit(void)
1981 {
1982         unregister_pernet_subsys(&tcpv6_net_ops);
1983         inet6_unregister_protosw(&tcpv6_protosw);
1984         inet6_del_protocol(&tcpv6_protocol, IPPROTO_TCP);
1985 }