net/ipv6/tcp_ipv6.c

   1 /*
   2  *      TCP over IPv6
   3  *      Linux INET6 implementation
   4  *
   5  *      Authors:
   6  *      Pedro Roque             <[email protected]>
   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(struct sock *sk, struct sk_buff *skb);
  74 static void     tcp_v6_reqsk_send_ack(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(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) {
  97                 const struct rt6_info *rt = (const struct rt6_info *)dst;
  98
  99                 dst_hold(dst);
 100                 sk->sk_rx_dst = dst;
 101                 inet_sk(sk)->rx_dst_ifindex = skb->skb_iif;
 102                 if (rt->rt6i_node)
 103                         inet6_sk(sk)->rx_dst_cookie = rt->rt6i_node->fn_sernum;
 104         }
 105 }
 106
 107 static __u32 tcp_v6_init_sequence(const struct sk_buff *skb)
 108 {
 109         return secure_tcpv6_sequence_number(ipv6_hdr(skb)->daddr.s6_addr32,
 110                                             ipv6_hdr(skb)->saddr.s6_addr32,
 111                                             tcp_hdr(skb)->dest,
 112                                             tcp_hdr(skb)->source);
 113 }
 114
 115 static int tcp_v6_connect(struct sock *sk, struct sockaddr *uaddr,
 116                           int addr_len)
 117 {
 118         struct sockaddr_in6 *usin = (struct sockaddr_in6 *) uaddr;
 119         struct inet_sock *inet = inet_sk(sk);
 120         struct inet_connection_sock *icsk = inet_csk(sk);
 121         struct ipv6_pinfo *np = inet6_sk(sk);
 122         struct tcp_sock *tp = tcp_sk(sk);
 123         struct in6_addr *saddr = NULL, *final_p, final;
 124         struct rt6_info *rt;
 125         struct flowi6 fl6;
 126         struct dst_entry *dst;
 127         int addr_type;
 128         int err;
 129
 130         if (addr_len < SIN6_LEN_RFC2133)
 131                 return -EINVAL;
 132
 133         if (usin->sin6_family != AF_INET6)
 134                 return -EAFNOSUPPORT;
 135
 136         memset(&fl6, 0, sizeof(fl6));
 137
 138         if (np->sndflow) {
 139                 fl6.flowlabel = usin->sin6_flowinfo&IPV6_FLOWINFO_MASK;
 140                 IP6_ECN_flow_init(fl6.flowlabel);
 141                 if (fl6.flowlabel&IPV6_FLOWLABEL_MASK) {
 142                         struct ip6_flowlabel *flowlabel;
 143                         flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
 144                         if (!flowlabel)
 145                                 return -EINVAL;
 146                         fl6_sock_release(flowlabel);
 147                 }
 148         }
 149
 150         /*
 151          *      connect() to INADDR_ANY means loopback (BSD'ism).
 152          */
 153
 154         if (ipv6_addr_any(&usin->sin6_addr))
 155                 usin->sin6_addr.s6_addr[15] = 0x1;
 156
 157         addr_type = ipv6_addr_type(&usin->sin6_addr);
 158
 159         if (addr_type & IPV6_ADDR_MULTICAST)
 160                 return -ENETUNREACH;
 161
 162         if (addr_type&IPV6_ADDR_LINKLOCAL) {
 163                 if (addr_len >= sizeof(struct sockaddr_in6) &&
 164                     usin->sin6_scope_id) {
 165                         /* If interface is set while binding, indices
 166                          * must coincide.
 167                          */
 168                         if (sk->sk_bound_dev_if &&
 169                             sk->sk_bound_dev_if != usin->sin6_scope_id)
 170                                 return -EINVAL;
 171
 172                         sk->sk_bound_dev_if = usin->sin6_scope_id;
 173                 }
 174
 175                 /* Connect to link-local address requires an interface */
 176                 if (!sk->sk_bound_dev_if)
 177                         return -EINVAL;
 178         }
 179
 180         if (tp->rx_opt.ts_recent_stamp &&
 181             !ipv6_addr_equal(&sk->sk_v6_daddr, &usin->sin6_addr)) {
 182                 tp->rx_opt.ts_recent = 0;
 183                 tp->rx_opt.ts_recent_stamp = 0;
 184                 tp->write_seq = 0;
 185         }
 186
 187         sk->sk_v6_daddr = usin->sin6_addr;
 188         np->flow_label = fl6.flowlabel;
 189
 190         /*
 191          *      TCP over IPv4
 192          */
 193
 194         if (addr_type == IPV6_ADDR_MAPPED) {
 195                 u32 exthdrlen = icsk->icsk_ext_hdr_len;
 196                 struct sockaddr_in sin;
 197
 198                 SOCK_DEBUG(sk, "connect: ipv4 mapped\n");
 199
 200                 if (__ipv6_only_sock(sk))
 201                         return -ENETUNREACH;
 202
 203                 sin.sin_family = AF_INET;
 204                 sin.sin_port = usin->sin6_port;
 205                 sin.sin_addr.s_addr = usin->sin6_addr.s6_addr32[3];
 206
 207                 icsk->icsk_af_ops = &ipv6_mapped;
 208                 sk->sk_backlog_rcv = tcp_v4_do_rcv;
 209 #ifdef CONFIG_TCP_MD5SIG
 210                 tp->af_specific = &tcp_sock_ipv6_mapped_specific;
 211 #endif
 212
 213                 err = tcp_v4_connect(sk, (struct sockaddr *)&sin, sizeof(sin));
 214
 215                 if (err) {
 216                         icsk->icsk_ext_hdr_len = exthdrlen;
 217                         icsk->icsk_af_ops = &ipv6_specific;
 218                         sk->sk_backlog_rcv = tcp_v6_do_rcv;
 219 #ifdef CONFIG_TCP_MD5SIG
 220                         tp->af_specific = &tcp_sock_ipv6_specific;
 221 #endif
 222                         goto failure;
 223                 }
 224                 np->saddr = sk->sk_v6_rcv_saddr;
 225
 226                 return err;
 227         }
 228
 229         if (!ipv6_addr_any(&sk->sk_v6_rcv_saddr))
 230                 saddr = &sk->sk_v6_rcv_saddr;
 231
 232         fl6.flowi6_proto = IPPROTO_TCP;
 233         fl6.daddr = sk->sk_v6_daddr;
 234         fl6.saddr = saddr ? *saddr : np->saddr;
 235         fl6.flowi6_oif = sk->sk_bound_dev_if;
 236         fl6.flowi6_mark = sk->sk_mark;
 237         fl6.fl6_dport = usin->sin6_port;
 238         fl6.fl6_sport = inet->inet_sport;
 239
 240         final_p = fl6_update_dst(&fl6, np->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         rt = (struct rt6_info *) dst;
 263         if (tcp_death_row.sysctl_tw_recycle &&
 264             !tp->rx_opt.ts_recent_stamp &&
 265             ipv6_addr_equal(&rt->rt6i_dst.addr, &sk->sk_v6_daddr))
 266                 tcp_fetch_timewait_stamp(sk, dst);
 267
 268         icsk->icsk_ext_hdr_len = 0;
 269         if (np->opt)
 270                 icsk->icsk_ext_hdr_len = (np->opt->opt_flen +
 271                                           np->opt->opt_nflen);
 272
 273         tp->rx_opt.mss_clamp = IPV6_MIN_MTU - sizeof(struct tcphdr) - sizeof(struct ipv6hdr);
 274
 275         inet->inet_dport = usin->sin6_port;
 276
 277         tcp_set_state(sk, TCP_SYN_SENT);
 278         err = inet6_hash_connect(&tcp_death_row, sk);
 279         if (err)
 280                 goto late_failure;
 281
 282         ip6_set_txhash(sk);
 283
 284         if (!tp->write_seq && likely(!tp->repair))
 285                 tp->write_seq = secure_tcpv6_sequence_number(np->saddr.s6_addr32,
 286                                                              sk->sk_v6_daddr.s6_addr32,
 287                                                              inet->inet_sport,
 288                                                              inet->inet_dport);
 289
 290         err = tcp_connect(sk);
 291         if (err)
 292                 goto late_failure;
 293
 294         return 0;
 295
 296 late_failure:
 297         tcp_set_state(sk, TCP_CLOSE);
 298         __sk_dst_reset(sk);
 299 failure:
 300         inet->inet_dport = 0;
 301         sk->sk_route_caps = 0;
 302         return err;
 303 }
 304
 305 static void tcp_v6_mtu_reduced(struct sock *sk)
 306 {
 307         struct dst_entry *dst;
 308
 309         if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE))
 310                 return;
 311
 312         dst = inet6_csk_update_pmtu(sk, tcp_sk(sk)->mtu_info);
 313         if (!dst)
 314                 return;
 315
 316         if (inet_csk(sk)->icsk_pmtu_cookie > dst_mtu(dst)) {
 317                 tcp_sync_mss(sk, dst_mtu(dst));
 318                 tcp_simple_retransmit(sk);
 319         }
 320 }
 321
 322 static void tcp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 323                 u8 type, u8 code, int offset, __be32 info)
 324 {
 325         const struct ipv6hdr *hdr = (const struct ipv6hdr *)skb->data;
 326         const struct tcphdr *th = (struct tcphdr *)(skb->data+offset);
 327         struct net *net = dev_net(skb->dev);
 328         struct request_sock *fastopen;
 329         struct ipv6_pinfo *np;
 330         struct tcp_sock *tp;
 331         __u32 seq, snd_una;
 332         struct sock *sk;
 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         if (sk->sk_state == TCP_NEW_SYN_RECV)
 352                 return tcp_req_err(sk, seq);
 353
 354         bh_lock_sock(sk);
 355         if (sock_owned_by_user(sk) && type != ICMPV6_PKT_TOOBIG)
 356                 NET_INC_STATS_BH(net, LINUX_MIB_LOCKDROPPEDICMPS);
 357
 358         if (sk->sk_state == TCP_CLOSE)
 359                 goto out;
 360
 361         if (ipv6_hdr(skb)->hop_limit < inet6_sk(sk)->min_hopcount) {
 362                 NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP);
 363                 goto out;
 364         }
 365
 366         tp = tcp_sk(sk);
 367         /* XXX (TFO) - tp->snd_una should be ISN (tcp_create_openreq_child() */
 368         fastopen = tp->fastopen_rsk;
 369         snd_una = fastopen ? tcp_rsk(fastopen)->snt_isn : tp->snd_una;
 370         if (sk->sk_state != TCP_LISTEN &&
 371             !between(seq, snd_una, tp->snd_nxt)) {
 372                 NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
 373                 goto out;
 374         }
 375
 376         np = inet6_sk(sk);
 377
 378         if (type == NDISC_REDIRECT) {
 379                 struct dst_entry *dst = __sk_dst_check(sk, np->dst_cookie);
 380
 381                 if (dst)
 382                         dst->ops->redirect(dst, sk, skb);
 383                 goto out;
 384         }
 385
 386         if (type == ICMPV6_PKT_TOOBIG) {
 387                 /* We are not interested in TCP_LISTEN and open_requests
 388                  * (SYN-ACKs send out by Linux are always <576bytes so
 389                  * they should go through unfragmented).
 390                  */
 391                 if (sk->sk_state == TCP_LISTEN)
 392                         goto out;
 393
 394                 if (!ip6_sk_accept_pmtu(sk))
 395                         goto out;
 396
 397                 tp->mtu_info = ntohl(info);
 398                 if (!sock_owned_by_user(sk))
 399                         tcp_v6_mtu_reduced(sk);
 400                 else if (!test_and_set_bit(TCP_MTU_REDUCED_DEFERRED,
 401                                            &tp->tsq_flags))
 402                         sock_hold(sk);
 403                 goto out;
 404         }
 405
 406         icmpv6_err_convert(type, code, &err);
 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(struct sock *sk, struct dst_entry *dst,
 441                               struct flowi *fl,
 442                               struct request_sock *req,
 443                               u16 queue_mapping,
 444                               struct tcp_fastopen_cookie *foc)
 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)) == NULL)
 454                 goto done;
 455
 456         skb = tcp_make_synack(sk, dst, req, foc);
 457
 458         if (skb) {
 459                 __tcp_v6_send_check(skb, &ireq->ir_v6_loc_addr,
 460                                     &ireq->ir_v6_rmt_addr);
 461
 462                 fl6->daddr = ireq->ir_v6_rmt_addr;
 463                 if (np->repflow && ireq->pktopts)
 464                         fl6->flowlabel = ip6_flowlabel(ipv6_hdr(ireq->pktopts));
 465
 466                 skb_set_queue_mapping(skb, queue_mapping);
 467                 err = ip6_xmit(sk, skb, fl6, np->opt, np->tclass);
 468                 err = net_xmit_eval(err);
 469         }
 470
 471 done:
 472         return err;
 473 }
 474
 475
 476 static void tcp_v6_reqsk_destructor(struct request_sock *req)
 477 {
 478         kfree_skb(inet_rsk(req)->pktopts);
 479 }
 480
 481 #ifdef CONFIG_TCP_MD5SIG
 482 static struct tcp_md5sig_key *tcp_v6_md5_do_lookup(struct sock *sk,
 483                                                    const struct in6_addr *addr)
 484 {
 485         return tcp_md5_do_lookup(sk, (union tcp_md5_addr *)addr, AF_INET6);
 486 }
 487
 488 static struct tcp_md5sig_key *tcp_v6_md5_lookup(struct sock *sk,
 489                                                 const struct sock *addr_sk)
 490 {
 491         return tcp_v6_md5_do_lookup(sk, &addr_sk->sk_v6_daddr);
 492 }
 493
 494 static int tcp_v6_parse_md5_keys(struct sock *sk, char __user *optval,
 495                                  int optlen)
 496 {
 497         struct tcp_md5sig cmd;
 498         struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)&cmd.tcpm_addr;
 499
 500         if (optlen < sizeof(cmd))
 501                 return -EINVAL;
 502
 503         if (copy_from_user(&cmd, optval, sizeof(cmd)))
 504                 return -EFAULT;
 505
 506         if (sin6->sin6_family != AF_INET6)
 507                 return -EINVAL;
 508
 509         if (!cmd.tcpm_keylen) {
 510                 if (ipv6_addr_v4mapped(&sin6->sin6_addr))
 511                         return tcp_md5_do_del(sk, (union tcp_md5_addr *)&sin6->sin6_addr.s6_addr32[3],
 512                                               AF_INET);
 513                 return tcp_md5_do_del(sk, (union tcp_md5_addr *)&sin6->sin6_addr,
 514                                       AF_INET6);
 515         }
 516
 517         if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN)
 518                 return -EINVAL;
 519
 520         if (ipv6_addr_v4mapped(&sin6->sin6_addr))
 521                 return tcp_md5_do_add(sk, (union tcp_md5_addr *)&sin6->sin6_addr.s6_addr32[3],
 522                                       AF_INET, cmd.tcpm_key, cmd.tcpm_keylen, GFP_KERNEL);
 523
 524         return tcp_md5_do_add(sk, (union tcp_md5_addr *)&sin6->sin6_addr,
 525                               AF_INET6, cmd.tcpm_key, cmd.tcpm_keylen, GFP_KERNEL);
 526 }
 527
 528 static int tcp_v6_md5_hash_pseudoheader(struct tcp_md5sig_pool *hp,
 529                                         const struct in6_addr *daddr,
 530                                         const struct in6_addr *saddr, int nbytes)
 531 {
 532         struct tcp6_pseudohdr *bp;
 533         struct scatterlist sg;
 534
 535         bp = &hp->md5_blk.ip6;
 536         /* 1. TCP pseudo-header (RFC2460) */
 537         bp->saddr = *saddr;
 538         bp->daddr = *daddr;
 539         bp->protocol = cpu_to_be32(IPPROTO_TCP);
 540         bp->len = cpu_to_be32(nbytes);
 541
 542         sg_init_one(&sg, bp, sizeof(*bp));
 543         return crypto_hash_update(&hp->md5_desc, &sg, sizeof(*bp));
 544 }
 545
 546 static int tcp_v6_md5_hash_hdr(char *md5_hash, struct tcp_md5sig_key *key,
 547                                const struct in6_addr *daddr, struct in6_addr *saddr,
 548                                const struct tcphdr *th)
 549 {
 550         struct tcp_md5sig_pool *hp;
 551         struct hash_desc *desc;
 552
 553         hp = tcp_get_md5sig_pool();
 554         if (!hp)
 555                 goto clear_hash_noput;
 556         desc = &hp->md5_desc;
 557
 558         if (crypto_hash_init(desc))
 559                 goto clear_hash;
 560         if (tcp_v6_md5_hash_pseudoheader(hp, daddr, saddr, th->doff << 2))
 561                 goto clear_hash;
 562         if (tcp_md5_hash_header(hp, th))
 563                 goto clear_hash;
 564         if (tcp_md5_hash_key(hp, key))
 565                 goto clear_hash;
 566         if (crypto_hash_final(desc, md5_hash))
 567                 goto clear_hash;
 568
 569         tcp_put_md5sig_pool();
 570         return 0;
 571
 572 clear_hash:
 573         tcp_put_md5sig_pool();
 574 clear_hash_noput:
 575         memset(md5_hash, 0, 16);
 576         return 1;
 577 }
 578
 579 static int tcp_v6_md5_hash_skb(char *md5_hash,
 580                                const struct tcp_md5sig_key *key,
 581                                const struct sock *sk,
 582                                const struct sk_buff *skb)
 583 {
 584         const struct in6_addr *saddr, *daddr;
 585         struct tcp_md5sig_pool *hp;
 586         struct hash_desc *desc;
 587         const struct tcphdr *th = tcp_hdr(skb);
 588
 589         if (sk) { /* valid for establish/request sockets */
 590                 saddr = &sk->sk_v6_rcv_saddr;
 591                 daddr = &sk->sk_v6_daddr;
 592         } else {
 593                 const struct ipv6hdr *ip6h = ipv6_hdr(skb);
 594                 saddr = &ip6h->saddr;
 595                 daddr = &ip6h->daddr;
 596         }
 597
 598         hp = tcp_get_md5sig_pool();
 599         if (!hp)
 600                 goto clear_hash_noput;
 601         desc = &hp->md5_desc;
 602
 603         if (crypto_hash_init(desc))
 604                 goto clear_hash;
 605
 606         if (tcp_v6_md5_hash_pseudoheader(hp, daddr, saddr, skb->len))
 607                 goto clear_hash;
 608         if (tcp_md5_hash_header(hp, th))
 609                 goto clear_hash;
 610         if (tcp_md5_hash_skb_data(hp, skb, th->doff << 2))
 611                 goto clear_hash;
 612         if (tcp_md5_hash_key(hp, key))
 613                 goto clear_hash;
 614         if (crypto_hash_final(desc, md5_hash))
 615                 goto clear_hash;
 616
 617         tcp_put_md5sig_pool();
 618         return 0;
 619
 620 clear_hash:
 621         tcp_put_md5sig_pool();
 622 clear_hash_noput:
 623         memset(md5_hash, 0, 16);
 624         return 1;
 625 }
 626
 627 static bool tcp_v6_inbound_md5_hash(struct sock *sk, const struct sk_buff *skb)
 628 {
 629         const __u8 *hash_location = NULL;
 630         struct tcp_md5sig_key *hash_expected;
 631         const struct ipv6hdr *ip6h = ipv6_hdr(skb);
 632         const struct tcphdr *th = tcp_hdr(skb);
 633         int genhash;
 634         u8 newhash[16];
 635
 636         hash_expected = tcp_v6_md5_do_lookup(sk, &ip6h->saddr);
 637         hash_location = tcp_parse_md5sig_option(th);
 638
 639         /* We've parsed the options - do we have a hash? */
 640         if (!hash_expected && !hash_location)
 641                 return false;
 642
 643         if (hash_expected && !hash_location) {
 644                 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5NOTFOUND);
 645                 return true;
 646         }
 647
 648         if (!hash_expected && hash_location) {
 649                 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5UNEXPECTED);
 650                 return true;
 651         }
 652
 653         /* check the signature */
 654         genhash = tcp_v6_md5_hash_skb(newhash,
 655                                       hash_expected,
 656                                       NULL, skb);
 657
 658         if (genhash || memcmp(hash_location, newhash, 16) != 0) {
 659                 net_info_ratelimited("MD5 Hash %s for [%pI6c]:%u->[%pI6c]:%u\n",
 660                                      genhash ? "failed" : "mismatch",
 661                                      &ip6h->saddr, ntohs(th->source),
 662                                      &ip6h->daddr, ntohs(th->dest));
 663                 return true;
 664         }
 665         return false;
 666 }
 667 #endif
 668
 669 static void tcp_v6_init_req(struct request_sock *req, struct sock *sk,
 670                             struct sk_buff *skb)
 671 {
 672         struct inet_request_sock *ireq = inet_rsk(req);
 673         struct ipv6_pinfo *np = inet6_sk(sk);
 674
 675         ireq->ir_v6_rmt_addr = ipv6_hdr(skb)->saddr;
 676         ireq->ir_v6_loc_addr = ipv6_hdr(skb)->daddr;
 677
 678         /* So that link locals have meaning */
 679         if (!sk->sk_bound_dev_if &&
 680             ipv6_addr_type(&ireq->ir_v6_rmt_addr) & IPV6_ADDR_LINKLOCAL)
 681                 ireq->ir_iif = tcp_v6_iif(skb);
 682
 683         if (!TCP_SKB_CB(skb)->tcp_tw_isn &&
 684             (ipv6_opt_accepted(sk, skb, &TCP_SKB_CB(skb)->header.h6) ||
 685              np->rxopt.bits.rxinfo ||
 686              np->rxopt.bits.rxoinfo || np->rxopt.bits.rxhlim ||
 687              np->rxopt.bits.rxohlim || np->repflow)) {
 688                 atomic_inc(&skb->users);
 689                 ireq->pktopts = skb;
 690         }
 691 }
 692
 693 static struct dst_entry *tcp_v6_route_req(struct sock *sk, struct flowi *fl,
 694                                           const struct request_sock *req,
 695                                           bool *strict)
 696 {
 697         if (strict)
 698                 *strict = true;
 699         return inet6_csk_route_req(sk, &fl->u.ip6, req);
 700 }
 701
 702 struct request_sock_ops tcp6_request_sock_ops __read_mostly = {
 703         .family         =       AF_INET6,
 704         .obj_size       =       sizeof(struct tcp6_request_sock),
 705         .rtx_syn_ack    =       tcp_rtx_synack,
 706         .send_ack       =       tcp_v6_reqsk_send_ack,
 707         .destructor     =       tcp_v6_reqsk_destructor,
 708         .send_reset     =       tcp_v6_send_reset,
 709         .syn_ack_timeout =      tcp_syn_ack_timeout,
 710 };
 711
 712 static const struct tcp_request_sock_ops tcp_request_sock_ipv6_ops = {
 713         .mss_clamp      =       IPV6_MIN_MTU - sizeof(struct tcphdr) -
 714                                 sizeof(struct ipv6hdr),
 715 #ifdef CONFIG_TCP_MD5SIG
 716         .req_md5_lookup =       tcp_v6_md5_lookup,
 717         .calc_md5_hash  =       tcp_v6_md5_hash_skb,
 718 #endif
 719         .init_req       =       tcp_v6_init_req,
 720 #ifdef CONFIG_SYN_COOKIES
 721         .cookie_init_seq =      cookie_v6_init_sequence,
 722 #endif
 723         .route_req      =       tcp_v6_route_req,
 724         .init_seq       =       tcp_v6_init_sequence,
 725         .send_synack    =       tcp_v6_send_synack,
 726         .queue_hash_add =       inet6_csk_reqsk_queue_hash_add,
 727 };
 728
 729 static void tcp_v6_send_response(struct sock *sk, struct sk_buff *skb, u32 seq,
 730                                  u32 ack, u32 win, u32 tsval, u32 tsecr,
 731                                  int oif, struct tcp_md5sig_key *key, int rst,
 732                                  u8 tclass, u32 label)
 733 {
 734         const struct tcphdr *th = tcp_hdr(skb);
 735         struct tcphdr *t1;
 736         struct sk_buff *buff;
 737         struct flowi6 fl6;
 738         struct net *net = sk ? sock_net(sk) : dev_net(skb_dst(skb)->dev);
 739         struct sock *ctl_sk = net->ipv6.tcp_sk;
 740         unsigned int tot_len = sizeof(struct tcphdr);
 741         struct dst_entry *dst;
 742         __be32 *topt;
 743
 744         if (tsecr)
 745                 tot_len += TCPOLEN_TSTAMP_ALIGNED;
 746 #ifdef CONFIG_TCP_MD5SIG
 747         if (key)
 748                 tot_len += TCPOLEN_MD5SIG_ALIGNED;
 749 #endif
 750
 751         buff = alloc_skb(MAX_HEADER + sizeof(struct ipv6hdr) + tot_len,
 752                          GFP_ATOMIC);
 753         if (!buff)
 754                 return;
 755
 756         skb_reserve(buff, MAX_HEADER + sizeof(struct ipv6hdr) + tot_len);
 757
 758         t1 = (struct tcphdr *) skb_push(buff, tot_len);
 759         skb_reset_transport_header(buff);
 760
 761         /* Swap the send and the receive. */
 762         memset(t1, 0, sizeof(*t1));
 763         t1->dest = th->source;
 764         t1->source = th->dest;
 765         t1->doff = tot_len / 4;
 766         t1->seq = htonl(seq);
 767         t1->ack_seq = htonl(ack);
 768         t1->ack = !rst || !th->ack;
 769         t1->rst = rst;
 770         t1->window = htons(win);
 771
 772         topt = (__be32 *)(t1 + 1);
 773
 774         if (tsecr) {
 775                 *topt++ = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
 776                                 (TCPOPT_TIMESTAMP << 8) | TCPOLEN_TIMESTAMP);
 777                 *topt++ = htonl(tsval);
 778                 *topt++ = htonl(tsecr);
 779         }
 780
 781 #ifdef CONFIG_TCP_MD5SIG
 782         if (key) {
 783                 *topt++ = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
 784                                 (TCPOPT_MD5SIG << 8) | TCPOLEN_MD5SIG);
 785                 tcp_v6_md5_hash_hdr((__u8 *)topt, key,
 786                                     &ipv6_hdr(skb)->saddr,
 787                                     &ipv6_hdr(skb)->daddr, t1);
 788         }
 789 #endif
 790
 791         memset(&fl6, 0, sizeof(fl6));
 792         fl6.daddr = ipv6_hdr(skb)->saddr;
 793         fl6.saddr = ipv6_hdr(skb)->daddr;
 794         fl6.flowlabel = label;
 795
 796         buff->ip_summed = CHECKSUM_PARTIAL;
 797         buff->csum = 0;
 798
 799         __tcp_v6_send_check(buff, &fl6.saddr, &fl6.daddr);
 800
 801         fl6.flowi6_proto = IPPROTO_TCP;
 802         if (rt6_need_strict(&fl6.daddr) && !oif)
 803                 fl6.flowi6_oif = tcp_v6_iif(skb);
 804         else
 805                 fl6.flowi6_oif = oif;
 806         fl6.flowi6_mark = IP6_REPLY_MARK(net, skb->mark);
 807         fl6.fl6_dport = t1->dest;
 808         fl6.fl6_sport = t1->source;
 809         security_skb_classify_flow(skb, flowi6_to_flowi(&fl6));
 810
 811         /* Pass a socket to ip6_dst_lookup either it is for RST
 812          * Underlying function will use this to retrieve the network
 813          * namespace
 814          */
 815         dst = ip6_dst_lookup_flow(ctl_sk, &fl6, NULL);
 816         if (!IS_ERR(dst)) {
 817                 skb_dst_set(buff, dst);
 818                 ip6_xmit(ctl_sk, buff, &fl6, NULL, tclass);
 819                 TCP_INC_STATS_BH(net, TCP_MIB_OUTSEGS);
 820                 if (rst)
 821                         TCP_INC_STATS_BH(net, TCP_MIB_OUTRSTS);
 822                 return;
 823         }
 824
 825         kfree_skb(buff);
 826 }
 827
 828 static void tcp_v6_send_reset(struct sock *sk, struct sk_buff *skb)
 829 {
 830         const struct tcphdr *th = tcp_hdr(skb);
 831         u32 seq = 0, ack_seq = 0;
 832         struct tcp_md5sig_key *key = NULL;
 833 #ifdef CONFIG_TCP_MD5SIG
 834         const __u8 *hash_location = NULL;
 835         struct ipv6hdr *ipv6h = ipv6_hdr(skb);
 836         unsigned char newhash[16];
 837         int genhash;
 838         struct sock *sk1 = NULL;
 839 #endif
 840         int oif;
 841
 842         if (th->rst)
 843                 return;
 844
 845         /* If sk not NULL, it means we did a successful lookup and incoming
 846          * route had to be correct. prequeue might have dropped our dst.
 847          */
 848         if (!sk && !ipv6_unicast_destination(skb))
 849                 return;
 850
 851 #ifdef CONFIG_TCP_MD5SIG
 852         hash_location = tcp_parse_md5sig_option(th);
 853         if (!sk && hash_location) {
 854                 /*
 855                  * active side is lost. Try to find listening socket through
 856                  * source port, and then find md5 key through listening socket.
 857                  * we are not loose security here:
 858                  * Incoming packet is checked with md5 hash with finding key,
 859                  * no RST generated if md5 hash doesn't match.
 860                  */
 861                 sk1 = inet6_lookup_listener(dev_net(skb_dst(skb)->dev),
 862                                            &tcp_hashinfo, &ipv6h->saddr,
 863                                            th->source, &ipv6h->daddr,
 864                                            ntohs(th->source), tcp_v6_iif(skb));
 865                 if (!sk1)
 866                         return;
 867
 868                 rcu_read_lock();
 869                 key = tcp_v6_md5_do_lookup(sk1, &ipv6h->saddr);
 870                 if (!key)
 871                         goto release_sk1;
 872
 873                 genhash = tcp_v6_md5_hash_skb(newhash, key, NULL, skb);
 874                 if (genhash || memcmp(hash_location, newhash, 16) != 0)
 875                         goto release_sk1;
 876         } else {
 877                 key = sk ? tcp_v6_md5_do_lookup(sk, &ipv6h->saddr) : NULL;
 878         }
 879 #endif
 880
 881         if (th->ack)
 882                 seq = ntohl(th->ack_seq);
 883         else
 884                 ack_seq = ntohl(th->seq) + th->syn + th->fin + skb->len -
 885                           (th->doff << 2);
 886
 887         oif = sk ? sk->sk_bound_dev_if : 0;
 888         tcp_v6_send_response(sk, skb, seq, ack_seq, 0, 0, 0, oif, key, 1, 0, 0);
 889
 890 #ifdef CONFIG_TCP_MD5SIG
 891 release_sk1:
 892         if (sk1) {
 893                 rcu_read_unlock();
 894                 sock_put(sk1);
 895         }
 896 #endif
 897 }
 898
 899 static void tcp_v6_send_ack(struct sock *sk, struct sk_buff *skb, u32 seq,
 900                             u32 ack, u32 win, u32 tsval, u32 tsecr, int oif,
 901                             struct tcp_md5sig_key *key, u8 tclass,
 902                             u32 label)
 903 {
 904         tcp_v6_send_response(sk, skb, seq, ack, win, tsval, tsecr, oif, key, 0,
 905                              tclass, label);
 906 }
 907
 908 static void tcp_v6_timewait_ack(struct sock *sk, struct sk_buff *skb)
 909 {
 910         struct inet_timewait_sock *tw = inet_twsk(sk);
 911         struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
 912
 913         tcp_v6_send_ack(sk, skb, tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
 914                         tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
 915                         tcp_time_stamp + tcptw->tw_ts_offset,
 916                         tcptw->tw_ts_recent, tw->tw_bound_dev_if, tcp_twsk_md5_key(tcptw),
 917                         tw->tw_tclass, cpu_to_be32(tw->tw_flowlabel));
 918
 919         inet_twsk_put(tw);
 920 }
 921
 922 static void tcp_v6_reqsk_send_ack(struct sock *sk, struct sk_buff *skb,
 923                                   struct request_sock *req)
 924 {
 925         /* sk->sk_state == TCP_LISTEN -> for regular TCP_SYN_RECV
 926          * sk->sk_state == TCP_SYN_RECV -> for Fast Open.
 927          */
 928         tcp_v6_send_ack(sk, skb, (sk->sk_state == TCP_LISTEN) ?
 929                         tcp_rsk(req)->snt_isn + 1 : tcp_sk(sk)->snd_nxt,
 930                         tcp_rsk(req)->rcv_nxt, req->rcv_wnd,
 931                         tcp_time_stamp, req->ts_recent, sk->sk_bound_dev_if,
 932                         tcp_v6_md5_do_lookup(sk, &ipv6_hdr(skb)->daddr),
 933                         0, 0);
 934 }
 935
 936
 937 static struct sock *tcp_v6_hnd_req(struct sock *sk, struct sk_buff *skb)
 938 {
 939         const struct tcphdr *th = tcp_hdr(skb);
 940         struct request_sock *req;
 941         struct sock *nsk;
 942
 943         /* Find possible connection requests. */
 944         req = inet6_csk_search_req(sk, th->source,
 945                                    &ipv6_hdr(skb)->saddr,
 946                                    &ipv6_hdr(skb)->daddr, tcp_v6_iif(skb));
 947         if (req) {
 948                 nsk = tcp_check_req(sk, skb, req, false);
 949                 if (!nsk)
 950                         reqsk_put(req);
 951                 return nsk;
 952         }
 953         nsk = __inet6_lookup_established(sock_net(sk), &tcp_hashinfo,
 954                                          &ipv6_hdr(skb)->saddr, th->source,
 955                                          &ipv6_hdr(skb)->daddr, ntohs(th->dest),
 956                                          tcp_v6_iif(skb));
 957
 958         if (nsk) {
 959                 if (nsk->sk_state != TCP_TIME_WAIT) {
 960                         bh_lock_sock(nsk);
 961                         return nsk;
 962                 }
 963                 inet_twsk_put(inet_twsk(nsk));
 964                 return NULL;
 965         }
 966
 967 #ifdef CONFIG_SYN_COOKIES
 968         if (!th->syn)
 969                 sk = cookie_v6_check(sk, skb);
 970 #endif
 971         return sk;
 972 }
 973
 974 static int tcp_v6_conn_request(struct sock *sk, struct sk_buff *skb)
 975 {
 976         if (skb->protocol == htons(ETH_P_IP))
 977                 return tcp_v4_conn_request(sk, skb);
 978
 979         if (!ipv6_unicast_destination(skb))
 980                 goto drop;
 981
 982         return tcp_conn_request(&tcp6_request_sock_ops,
 983                                 &tcp_request_sock_ipv6_ops, sk, skb);
 984
 985 drop:
 986         NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
 987         return 0; /* don't send reset */
 988 }
 989
 990 static struct sock *tcp_v6_syn_recv_sock(struct sock *sk, struct sk_buff *skb,
 991                                          struct request_sock *req,
 992                                          struct dst_entry *dst)
 993 {
 994         struct inet_request_sock *ireq;
 995         struct ipv6_pinfo *newnp, *np = inet6_sk(sk);
 996         struct tcp6_sock *newtcp6sk;
 997         struct inet_sock *newinet;
 998         struct tcp_sock *newtp;
 999         struct sock *newsk;
1000 #ifdef CONFIG_TCP_MD5SIG
1001         struct tcp_md5sig_key *key;
1002 #endif
1003         struct flowi6 fl6;
1004
1005         if (skb->protocol == htons(ETH_P_IP)) {
1006                 /*
1007                  *      v6 mapped
1008                  */
1009
1010                 newsk = tcp_v4_syn_recv_sock(sk, skb, req, dst);
1011
1012                 if (!newsk)
1013                         return NULL;
1014
1015                 newtcp6sk = (struct tcp6_sock *)newsk;
1016                 inet_sk(newsk)->pinet6 = &newtcp6sk->inet6;
1017
1018                 newinet = inet_sk(newsk);
1019                 newnp = inet6_sk(newsk);
1020                 newtp = tcp_sk(newsk);
1021
1022                 memcpy(newnp, np, sizeof(struct ipv6_pinfo));
1023
1024                 newnp->saddr = newsk->sk_v6_rcv_saddr;
1025
1026                 inet_csk(newsk)->icsk_af_ops = &ipv6_mapped;
1027                 newsk->sk_backlog_rcv = tcp_v4_do_rcv;
1028 #ifdef CONFIG_TCP_MD5SIG
1029                 newtp->af_specific = &tcp_sock_ipv6_mapped_specific;
1030 #endif
1031
1032                 newnp->ipv6_ac_list = NULL;
1033                 newnp->ipv6_fl_list = NULL;
1034                 newnp->pktoptions  = NULL;
1035                 newnp->opt         = NULL;
1036                 newnp->mcast_oif   = tcp_v6_iif(skb);
1037                 newnp->mcast_hops  = ipv6_hdr(skb)->hop_limit;
1038                 newnp->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(skb));
1039                 if (np->repflow)
1040                         newnp->flow_label = ip6_flowlabel(ipv6_hdr(skb));
1041
1042                 /*
1043                  * No need to charge this sock to the relevant IPv6 refcnt debug socks count
1044                  * here, tcp_create_openreq_child now does this for us, see the comment in
1045                  * that function for the gory details. -acme
1046                  */
1047
1048                 /* It is tricky place. Until this moment IPv4 tcp
1049                    worked with IPv6 icsk.icsk_af_ops.
1050                    Sync it now.
1051                  */
1052                 tcp_sync_mss(newsk, inet_csk(newsk)->icsk_pmtu_cookie);
1053
1054                 return newsk;
1055         }
1056
1057         ireq = inet_rsk(req);
1058
1059         if (sk_acceptq_is_full(sk))
1060                 goto out_overflow;
1061
1062         if (!dst) {
1063                 dst = inet6_csk_route_req(sk, &fl6, req);
1064                 if (!dst)
1065                         goto out;
1066         }
1067
1068         newsk = tcp_create_openreq_child(sk, req, skb);
1069         if (!newsk)
1070                 goto out_nonewsk;
1071
1072         /*
1073          * No need to charge this sock to the relevant IPv6 refcnt debug socks
1074          * count here, tcp_create_openreq_child now does this for us, see the
1075          * comment in that function for the gory details. -acme
1076          */
1077
1078         newsk->sk_gso_type = SKB_GSO_TCPV6;
1079         __ip6_dst_store(newsk, dst, NULL, NULL);
1080         inet6_sk_rx_dst_set(newsk, skb);
1081
1082         newtcp6sk = (struct tcp6_sock *)newsk;
1083         inet_sk(newsk)->pinet6 = &newtcp6sk->inet6;
1084
1085         newtp = tcp_sk(newsk);
1086         newinet = inet_sk(newsk);
1087         newnp = inet6_sk(newsk);
1088
1089         memcpy(newnp, np, sizeof(struct ipv6_pinfo));
1090
1091         newsk->sk_v6_daddr = ireq->ir_v6_rmt_addr;
1092         newnp->saddr = ireq->ir_v6_loc_addr;
1093         newsk->sk_v6_rcv_saddr = ireq->ir_v6_loc_addr;
1094         newsk->sk_bound_dev_if = ireq->ir_iif;
1095
1096         ip6_set_txhash(newsk);
1097
1098         /* Now IPv6 options...
1099
1100            First: no IPv4 options.
1101          */
1102         newinet->inet_opt = NULL;
1103         newnp->ipv6_ac_list = NULL;
1104         newnp->ipv6_fl_list = NULL;
1105
1106         /* Clone RX bits */
1107         newnp->rxopt.all = np->rxopt.all;
1108
1109         /* Clone pktoptions received with SYN */
1110         newnp->pktoptions = NULL;
1111         if (ireq->pktopts) {
1112                 newnp->pktoptions = skb_clone(ireq->pktopts,
1113                                               sk_gfp_atomic(sk, GFP_ATOMIC));
1114                 consume_skb(ireq->pktopts);
1115                 ireq->pktopts = NULL;
1116                 if (newnp->pktoptions)
1117                         skb_set_owner_r(newnp->pktoptions, newsk);
1118         }
1119         newnp->opt        = NULL;
1120         newnp->mcast_oif  = tcp_v6_iif(skb);
1121         newnp->mcast_hops = ipv6_hdr(skb)->hop_limit;
1122         newnp->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(skb));
1123         if (np->repflow)
1124                 newnp->flow_label = ip6_flowlabel(ipv6_hdr(skb));
1125
1126         /* Clone native IPv6 options from listening socket (if any)
1127
1128            Yes, keeping reference count would be much more clever,
1129            but we make one more one thing there: reattach optmem
1130            to newsk.
1131          */
1132         if (np->opt)
1133                 newnp->opt = ipv6_dup_options(newsk, np->opt);
1134
1135         inet_csk(newsk)->icsk_ext_hdr_len = 0;
1136         if (newnp->opt)
1137                 inet_csk(newsk)->icsk_ext_hdr_len = (newnp->opt->opt_nflen +
1138                                                      newnp->opt->opt_flen);
1139
1140         tcp_ca_openreq_child(newsk, dst);
1141
1142         tcp_sync_mss(newsk, dst_mtu(dst));
1143         newtp->advmss = dst_metric_advmss(dst);
1144         if (tcp_sk(sk)->rx_opt.user_mss &&
1145             tcp_sk(sk)->rx_opt.user_mss < newtp->advmss)
1146                 newtp->advmss = tcp_sk(sk)->rx_opt.user_mss;
1147
1148         tcp_initialize_rcv_mss(newsk);
1149
1150         newinet->inet_daddr = newinet->inet_saddr = LOOPBACK4_IPV6;
1151         newinet->inet_rcv_saddr = LOOPBACK4_IPV6;
1152
1153 #ifdef CONFIG_TCP_MD5SIG
1154         /* Copy over the MD5 key from the original socket */
1155         key = tcp_v6_md5_do_lookup(sk, &newsk->sk_v6_daddr);
1156         if (key) {
1157                 /* We're using one, so create a matching key
1158                  * on the newsk structure. If we fail to get
1159                  * memory, then we end up not copying the key
1160                  * across. Shucks.
1161                  */
1162                 tcp_md5_do_add(newsk, (union tcp_md5_addr *)&newsk->sk_v6_daddr,
1163                                AF_INET6, key->key, key->keylen,
1164                                sk_gfp_atomic(sk, GFP_ATOMIC));
1165         }
1166 #endif
1167
1168         if (__inet_inherit_port(sk, newsk) < 0) {
1169                 inet_csk_prepare_forced_close(newsk);
1170                 tcp_done(newsk);
1171                 goto out;
1172         }
1173         __inet_hash(newsk, NULL);
1174
1175         return newsk;
1176
1177 out_overflow:
1178         NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
1179 out_nonewsk:
1180         dst_release(dst);
1181 out:
1182         NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
1183         return NULL;
1184 }
1185
1186 /* The socket must have it's spinlock held when we get
1187  * here.
1188  *
1189  * We have a potential double-lock case here, so even when
1190  * doing backlog processing we use the BH locking scheme.
1191  * This is because we cannot sleep with the original spinlock
1192  * held.
1193  */
1194 static int tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb)
1195 {
1196         struct ipv6_pinfo *np = inet6_sk(sk);
1197         struct tcp_sock *tp;
1198         struct sk_buff *opt_skb = NULL;
1199
1200         /* Imagine: socket is IPv6. IPv4 packet arrives,
1201            goes to IPv4 receive handler and backlogged.
1202            From backlog it always goes here. Kerboom...
1203            Fortunately, tcp_rcv_established and rcv_established
1204            handle them correctly, but it is not case with
1205            tcp_v6_hnd_req and tcp_v6_send_reset().   --ANK
1206          */
1207
1208         if (skb->protocol == htons(ETH_P_IP))
1209                 return tcp_v4_do_rcv(sk, skb);
1210
1211         if (sk_filter(sk, skb))
1212                 goto discard;
1213
1214         /*
1215          *      socket locking is here for SMP purposes as backlog rcv
1216          *      is currently called with bh processing disabled.
1217          */
1218
1219         /* Do Stevens' IPV6_PKTOPTIONS.
1220
1221            Yes, guys, it is the only place in our code, where we
1222            may make it not affecting IPv4.
1223            The rest of code is protocol independent,
1224            and I do not like idea to uglify IPv4.
1225
1226            Actually, all the idea behind IPV6_PKTOPTIONS
1227            looks not very well thought. For now we latch
1228            options, received in the last packet, enqueued
1229            by tcp. Feel free to propose better solution.
1230                                                --ANK (980728)
1231          */
1232         if (np->rxopt.all)
1233                 opt_skb = skb_clone(skb, sk_gfp_atomic(sk, GFP_ATOMIC));
1234
1235         if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
1236                 struct dst_entry *dst = sk->sk_rx_dst;
1237
1238                 sock_rps_save_rxhash(sk, skb);
1239                 sk_mark_napi_id(sk, skb);
1240                 if (dst) {
1241                         if (inet_sk(sk)->rx_dst_ifindex != skb->skb_iif ||
1242                             dst->ops->check(dst, np->rx_dst_cookie) == NULL) {
1243                                 dst_release(dst);
1244                                 sk->sk_rx_dst = NULL;
1245                         }
1246                 }
1247
1248                 tcp_rcv_established(sk, skb, tcp_hdr(skb), skb->len);
1249                 if (opt_skb)
1250                         goto ipv6_pktoptions;
1251                 return 0;
1252         }
1253
1254         if (skb->len < tcp_hdrlen(skb) || tcp_checksum_complete(skb))
1255                 goto csum_err;
1256
1257         if (sk->sk_state == TCP_LISTEN) {
1258                 struct sock *nsk = tcp_v6_hnd_req(sk, skb);
1259                 if (!nsk)
1260                         goto discard;
1261
1262                 /*
1263                  * Queue it on the new socket if the new socket is active,
1264                  * otherwise we just shortcircuit this and continue with
1265                  * the new socket..
1266                  */
1267                 if (nsk != sk) {
1268                         sock_rps_save_rxhash(nsk, skb);
1269                         sk_mark_napi_id(sk, skb);
1270                         if (tcp_child_process(sk, nsk, skb))
1271                                 goto reset;
1272                         if (opt_skb)
1273                                 __kfree_skb(opt_skb);
1274                         return 0;
1275                 }
1276         } else
1277                 sock_rps_save_rxhash(sk, skb);
1278
1279         if (tcp_rcv_state_process(sk, skb, tcp_hdr(skb), skb->len))
1280                 goto reset;
1281         if (opt_skb)
1282                 goto ipv6_pktoptions;
1283         return 0;
1284
1285 reset:
1286         tcp_v6_send_reset(sk, skb);
1287 discard:
1288         if (opt_skb)
1289                 __kfree_skb(opt_skb);
1290         kfree_skb(skb);
1291         return 0;
1292 csum_err:
1293         TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_CSUMERRORS);
1294         TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_INERRS);
1295         goto discard;
1296
1297
1298 ipv6_pktoptions:
1299         /* Do you ask, what is it?
1300
1301            1. skb was enqueued by tcp.
1302            2. skb is added to tail of read queue, rather than out of order.
1303            3. socket is not in passive state.
1304            4. Finally, it really contains options, which user wants to receive.
1305          */
1306         tp = tcp_sk(sk);
1307         if (TCP_SKB_CB(opt_skb)->end_seq == tp->rcv_nxt &&
1308             !((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN))) {
1309                 if (np->rxopt.bits.rxinfo || np->rxopt.bits.rxoinfo)
1310                         np->mcast_oif = tcp_v6_iif(opt_skb);
1311                 if (np->rxopt.bits.rxhlim || np->rxopt.bits.rxohlim)
1312                         np->mcast_hops = ipv6_hdr(opt_skb)->hop_limit;
1313                 if (np->rxopt.bits.rxflow || np->rxopt.bits.rxtclass)
1314                         np->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(opt_skb));
1315                 if (np->repflow)
1316                         np->flow_label = ip6_flowlabel(ipv6_hdr(opt_skb));
1317                 if (ipv6_opt_accepted(sk, opt_skb, &TCP_SKB_CB(opt_skb)->header.h6)) {
1318                         skb_set_owner_r(opt_skb, sk);
1319                         opt_skb = xchg(&np->pktoptions, opt_skb);
1320                 } else {
1321                         __kfree_skb(opt_skb);
1322                         opt_skb = xchg(&np->pktoptions, NULL);
1323                 }
1324         }
1325
1326         kfree_skb(opt_skb);
1327         return 0;
1328 }
1329
1330 static void tcp_v6_fill_cb(struct sk_buff *skb, const struct ipv6hdr *hdr,
1331                            const struct tcphdr *th)
1332 {
1333         /* This is tricky: we move IP6CB at its correct location into
1334          * TCP_SKB_CB(). It must be done after xfrm6_policy_check(), because
1335          * _decode_session6() uses IP6CB().
1336          * barrier() makes sure compiler won't play aliasing games.
1337          */
1338         memmove(&TCP_SKB_CB(skb)->header.h6, IP6CB(skb),
1339                 sizeof(struct inet6_skb_parm));
1340         barrier();
1341
1342         TCP_SKB_CB(skb)->seq = ntohl(th->seq);
1343         TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
1344                                     skb->len - th->doff*4);
1345         TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
1346         TCP_SKB_CB(skb)->tcp_flags = tcp_flag_byte(th);
1347         TCP_SKB_CB(skb)->tcp_tw_isn = 0;
1348         TCP_SKB_CB(skb)->ip_dsfield = ipv6_get_dsfield(hdr);
1349         TCP_SKB_CB(skb)->sacked = 0;
1350 }
1351
1352 static void tcp_v6_restore_cb(struct sk_buff *skb)
1353 {
1354         /* We need to move header back to the beginning if xfrm6_policy_check()
1355          * and tcp_v6_fill_cb() are going to be called again.
1356          */
1357         memmove(IP6CB(skb), &TCP_SKB_CB(skb)->header.h6,
1358                 sizeof(struct inet6_skb_parm));
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         sk = __inet6_lookup_skb(&tcp_hashinfo, skb, th->source, th->dest,
1394                                 inet6_iif(skb));
1395         if (!sk)
1396                 goto no_tcp_socket;
1397
1398 process:
1399         if (sk->sk_state == TCP_TIME_WAIT)
1400                 goto do_time_wait;
1401
1402         if (hdr->hop_limit < inet6_sk(sk)->min_hopcount) {
1403                 NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP);
1404                 goto discard_and_relse;
1405         }
1406
1407         if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb))
1408                 goto discard_and_relse;
1409
1410         tcp_v6_fill_cb(skb, hdr, th);
1411
1412 #ifdef CONFIG_TCP_MD5SIG
1413         if (tcp_v6_inbound_md5_hash(sk, skb))
1414                 goto discard_and_relse;
1415 #endif
1416
1417         if (sk_filter(sk, skb))
1418                 goto discard_and_relse;
1419
1420         sk_incoming_cpu_update(sk);
1421         skb->dev = NULL;
1422
1423         bh_lock_sock_nested(sk);
1424         ret = 0;
1425         if (!sock_owned_by_user(sk)) {
1426                 if (!tcp_prequeue(sk, skb))
1427                         ret = tcp_v6_do_rcv(sk, skb);
1428         } else if (unlikely(sk_add_backlog(sk, skb,
1429                                            sk->sk_rcvbuf + sk->sk_sndbuf))) {
1430                 bh_unlock_sock(sk);
1431                 NET_INC_STATS_BH(net, LINUX_MIB_TCPBACKLOGDROP);
1432                 goto discard_and_relse;
1433         }
1434         bh_unlock_sock(sk);
1435
1436         sock_put(sk);
1437         return ret ? -1 : 0;
1438
1439 no_tcp_socket:
1440         if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb))
1441                 goto discard_it;
1442
1443         tcp_v6_fill_cb(skb, hdr, th);
1444
1445         if (skb->len < (th->doff<<2) || tcp_checksum_complete(skb)) {
1446 csum_error:
1447                 TCP_INC_STATS_BH(net, TCP_MIB_CSUMERRORS);
1448 bad_packet:
1449                 TCP_INC_STATS_BH(net, TCP_MIB_INERRS);
1450         } else {
1451                 tcp_v6_send_reset(NULL, skb);
1452         }
1453
1454 discard_it:
1455         kfree_skb(skb);
1456         return 0;
1457
1458 discard_and_relse:
1459         sock_put(sk);
1460         goto discard_it;
1461
1462 do_time_wait:
1463         if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
1464                 inet_twsk_put(inet_twsk(sk));
1465                 goto discard_it;
1466         }
1467
1468         tcp_v6_fill_cb(skb, hdr, th);
1469
1470         if (skb->len < (th->doff<<2)) {
1471                 inet_twsk_put(inet_twsk(sk));
1472                 goto bad_packet;
1473         }
1474         if (tcp_checksum_complete(skb)) {
1475                 inet_twsk_put(inet_twsk(sk));
1476                 goto csum_error;
1477         }
1478
1479         switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) {
1480         case TCP_TW_SYN:
1481         {
1482                 struct sock *sk2;
1483
1484                 sk2 = inet6_lookup_listener(dev_net(skb->dev), &tcp_hashinfo,
1485                                             &ipv6_hdr(skb)->saddr, th->source,
1486                                             &ipv6_hdr(skb)->daddr,
1487                                             ntohs(th->dest), tcp_v6_iif(skb));
1488                 if (sk2) {
1489                         struct inet_timewait_sock *tw = inet_twsk(sk);
1490                         inet_twsk_deschedule(tw);
1491                         inet_twsk_put(tw);
1492                         sk = sk2;
1493                         tcp_v6_restore_cb(skb);
1494                         goto process;
1495                 }
1496                 /* Fall through to ACK */
1497         }
1498         case TCP_TW_ACK:
1499                 tcp_v6_timewait_ack(sk, skb);
1500                 break;
1501         case TCP_TW_RST:
1502                 tcp_v6_restore_cb(skb);
1503                 goto no_tcp_socket;
1504         case TCP_TW_SUCCESS:
1505                 ;
1506         }
1507         goto discard_it;
1508 }
1509
1510 static void tcp_v6_early_demux(struct sk_buff *skb)
1511 {
1512         const struct ipv6hdr *hdr;
1513         const struct tcphdr *th;
1514         struct sock *sk;
1515
1516         if (skb->pkt_type != PACKET_HOST)
1517                 return;
1518
1519         if (!pskb_may_pull(skb, skb_transport_offset(skb) + sizeof(struct tcphdr)))
1520                 return;
1521
1522         hdr = ipv6_hdr(skb);
1523         th = tcp_hdr(skb);
1524
1525         if (th->doff < sizeof(struct tcphdr) / 4)
1526                 return;
1527
1528         /* Note : We use inet6_iif() here, not tcp_v6_iif() */
1529         sk = __inet6_lookup_established(dev_net(skb->dev), &tcp_hashinfo,
1530                                         &hdr->saddr, th->source,
1531                                         &hdr->daddr, ntohs(th->dest),
1532                                         inet6_iif(skb));
1533         if (sk) {
1534                 skb->sk = sk;
1535                 skb->destructor = sock_edemux;
1536                 if (sk_fullsock(sk)) {
1537                         struct dst_entry *dst = READ_ONCE(sk->sk_rx_dst);
1538
1539                         if (dst)
1540                                 dst = dst_check(dst, inet6_sk(sk)->rx_dst_cookie);
1541                         if (dst &&
1542                             inet_sk(sk)->rx_dst_ifindex == skb->skb_iif)
1543                                 skb_dst_set_noref(skb, dst);
1544                 }
1545         }
1546 }
1547
1548 static struct timewait_sock_ops tcp6_timewait_sock_ops = {
1549         .twsk_obj_size  = sizeof(struct tcp6_timewait_sock),
1550         .twsk_unique    = tcp_twsk_unique,
1551         .twsk_destructor = tcp_twsk_destructor,
1552 };
1553
1554 static const struct inet_connection_sock_af_ops ipv6_specific = {
1555         .queue_xmit        = inet6_csk_xmit,
1556         .send_check        = tcp_v6_send_check,
1557         .rebuild_header    = inet6_sk_rebuild_header,
1558         .sk_rx_dst_set     = inet6_sk_rx_dst_set,
1559         .conn_request      = tcp_v6_conn_request,
1560         .syn_recv_sock     = tcp_v6_syn_recv_sock,
1561         .net_header_len    = sizeof(struct ipv6hdr),
1562         .net_frag_header_len = sizeof(struct frag_hdr),
1563         .setsockopt        = ipv6_setsockopt,
1564         .getsockopt        = ipv6_getsockopt,
1565         .addr2sockaddr     = inet6_csk_addr2sockaddr,
1566         .sockaddr_len      = sizeof(struct sockaddr_in6),
1567         .bind_conflict     = inet6_csk_bind_conflict,
1568 #ifdef CONFIG_COMPAT
1569         .compat_setsockopt = compat_ipv6_setsockopt,
1570         .compat_getsockopt = compat_ipv6_getsockopt,
1571 #endif
1572         .mtu_reduced       = tcp_v6_mtu_reduced,
1573 };
1574
1575 #ifdef CONFIG_TCP_MD5SIG
1576 static const struct tcp_sock_af_ops tcp_sock_ipv6_specific = {
1577         .md5_lookup     =       tcp_v6_md5_lookup,
1578         .calc_md5_hash  =       tcp_v6_md5_hash_skb,
1579         .md5_parse      =       tcp_v6_parse_md5_keys,
1580 };
1581 #endif
1582
1583 /*
1584  *      TCP over IPv4 via INET6 API
1585  */
1586 static const struct inet_connection_sock_af_ops ipv6_mapped = {
1587         .queue_xmit        = ip_queue_xmit,
1588         .send_check        = tcp_v4_send_check,
1589         .rebuild_header    = inet_sk_rebuild_header,
1590         .sk_rx_dst_set     = inet_sk_rx_dst_set,
1591         .conn_request      = tcp_v6_conn_request,
1592         .syn_recv_sock     = tcp_v6_syn_recv_sock,
1593         .net_header_len    = sizeof(struct iphdr),
1594         .setsockopt        = ipv6_setsockopt,
1595         .getsockopt        = ipv6_getsockopt,
1596         .addr2sockaddr     = inet6_csk_addr2sockaddr,
1597         .sockaddr_len      = sizeof(struct sockaddr_in6),
1598         .bind_conflict     = inet6_csk_bind_conflict,
1599 #ifdef CONFIG_COMPAT
1600         .compat_setsockopt = compat_ipv6_setsockopt,
1601         .compat_getsockopt = compat_ipv6_getsockopt,
1602 #endif
1603         .mtu_reduced       = tcp_v4_mtu_reduced,
1604 };
1605
1606 #ifdef CONFIG_TCP_MD5SIG
1607 static const struct tcp_sock_af_ops tcp_sock_ipv6_mapped_specific = {
1608         .md5_lookup     =       tcp_v4_md5_lookup,
1609         .calc_md5_hash  =       tcp_v4_md5_hash_skb,
1610         .md5_parse      =       tcp_v6_parse_md5_keys,
1611 };
1612 #endif
1613
1614 /* NOTE: A lot of things set to zero explicitly by call to
1615  *       sk_alloc() so need not be done here.
1616  */
1617 static int tcp_v6_init_sock(struct sock *sk)
1618 {
1619         struct inet_connection_sock *icsk = inet_csk(sk);
1620
1621         tcp_init_sock(sk);
1622
1623         icsk->icsk_af_ops = &ipv6_specific;
1624
1625 #ifdef CONFIG_TCP_MD5SIG
1626         tcp_sk(sk)->af_specific = &tcp_sock_ipv6_specific;
1627 #endif
1628
1629         return 0;
1630 }
1631
1632 static void tcp_v6_destroy_sock(struct sock *sk)
1633 {
1634         tcp_v4_destroy_sock(sk);
1635         inet6_destroy_sock(sk);
1636 }
1637
1638 #ifdef CONFIG_PROC_FS
1639 /* Proc filesystem TCPv6 sock list dumping. */
1640 static void get_openreq6(struct seq_file *seq,
1641                          struct request_sock *req, int i, kuid_t uid)
1642 {
1643         long ttd = req->rsk_timer.expires - jiffies;
1644         const struct in6_addr *src = &inet_rsk(req)->ir_v6_loc_addr;
1645         const struct in6_addr *dest = &inet_rsk(req)->ir_v6_rmt_addr;
1646
1647         if (ttd < 0)
1648                 ttd = 0;
1649
1650         seq_printf(seq,
1651                    "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
1652                    "%02X %08X:%08X %02X:%08lX %08X %5u %8d %d %d %pK\n",
1653                    i,
1654                    src->s6_addr32[0], src->s6_addr32[1],
1655                    src->s6_addr32[2], src->s6_addr32[3],
1656                    inet_rsk(req)->ir_num,
1657                    dest->s6_addr32[0], dest->s6_addr32[1],
1658                    dest->s6_addr32[2], dest->s6_addr32[3],
1659                    ntohs(inet_rsk(req)->ir_rmt_port),
1660                    TCP_SYN_RECV,
1661                    0, 0, /* could print option size, but that is af dependent. */
1662                    1,   /* timers active (only the expire timer) */
1663                    jiffies_to_clock_t(ttd),
1664                    req->num_timeout,
1665                    from_kuid_munged(seq_user_ns(seq), uid),
1666                    0,  /* non standard timer */
1667                    0, /* open_requests have no inode */
1668                    0, req);
1669 }
1670
1671 static void get_tcp6_sock(struct seq_file *seq, struct sock *sp, int i)
1672 {
1673         const struct in6_addr *dest, *src;
1674         __u16 destp, srcp;
1675         int timer_active;
1676         unsigned long timer_expires;
1677         const struct inet_sock *inet = inet_sk(sp);
1678         const struct tcp_sock *tp = tcp_sk(sp);
1679         const struct inet_connection_sock *icsk = inet_csk(sp);
1680         struct fastopen_queue *fastopenq = icsk->icsk_accept_queue.fastopenq;
1681
1682         dest  = &sp->sk_v6_daddr;
1683         src   = &sp->sk_v6_rcv_saddr;
1684         destp = ntohs(inet->inet_dport);
1685         srcp  = ntohs(inet->inet_sport);
1686
1687         if (icsk->icsk_pending == ICSK_TIME_RETRANS) {
1688                 timer_active    = 1;
1689                 timer_expires   = icsk->icsk_timeout;
1690         } else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
1691                 timer_active    = 4;
1692                 timer_expires   = icsk->icsk_timeout;
1693         } else if (timer_pending(&sp->sk_timer)) {
1694                 timer_active    = 2;
1695                 timer_expires   = sp->sk_timer.expires;
1696         } else {
1697                 timer_active    = 0;
1698                 timer_expires = jiffies;
1699         }
1700
1701         seq_printf(seq,
1702                    "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
1703                    "%02X %08X:%08X %02X:%08lX %08X %5u %8d %lu %d %pK %lu %lu %u %u %d\n",
1704                    i,
1705                    src->s6_addr32[0], src->s6_addr32[1],
1706                    src->s6_addr32[2], src->s6_addr32[3], srcp,
1707                    dest->s6_addr32[0], dest->s6_addr32[1],
1708                    dest->s6_addr32[2], dest->s6_addr32[3], destp,
1709                    sp->sk_state,
1710                    tp->write_seq-tp->snd_una,
1711                    (sp->sk_state == TCP_LISTEN) ? sp->sk_ack_backlog : (tp->rcv_nxt - tp->copied_seq),
1712                    timer_active,
1713                    jiffies_delta_to_clock_t(timer_expires - jiffies),
1714                    icsk->icsk_retransmits,
1715                    from_kuid_munged(seq_user_ns(seq), sock_i_uid(sp)),
1716                    icsk->icsk_probes_out,
1717                    sock_i_ino(sp),
1718                    atomic_read(&sp->sk_refcnt), sp,
1719                    jiffies_to_clock_t(icsk->icsk_rto),
1720                    jiffies_to_clock_t(icsk->icsk_ack.ato),
1721                    (icsk->icsk_ack.quick << 1) | icsk->icsk_ack.pingpong,
1722                    tp->snd_cwnd,
1723                    sp->sk_state == TCP_LISTEN ?
1724                         (fastopenq ? fastopenq->max_qlen : 0) :
1725                         (tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh)
1726                    );
1727 }
1728
1729 static void get_timewait6_sock(struct seq_file *seq,
1730                                struct inet_timewait_sock *tw, int i)
1731 {
1732         long delta = tw->tw_timer.expires - jiffies;
1733         const struct in6_addr *dest, *src;
1734         __u16 destp, srcp;
1735
1736         dest = &tw->tw_v6_daddr;
1737         src  = &tw->tw_v6_rcv_saddr;
1738         destp = ntohs(tw->tw_dport);
1739         srcp  = ntohs(tw->tw_sport);
1740
1741         seq_printf(seq,
1742                    "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
1743                    "%02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK\n",
1744                    i,
1745                    src->s6_addr32[0], src->s6_addr32[1],
1746                    src->s6_addr32[2], src->s6_addr32[3], srcp,
1747                    dest->s6_addr32[0], dest->s6_addr32[1],
1748                    dest->s6_addr32[2], dest->s6_addr32[3], destp,
1749                    tw->tw_substate, 0, 0,
1750                    3, jiffies_delta_to_clock_t(delta), 0, 0, 0, 0,
1751                    atomic_read(&tw->tw_refcnt), tw);
1752 }
1753
1754 static int tcp6_seq_show(struct seq_file *seq, void *v)
1755 {
1756         struct tcp_iter_state *st;
1757         struct sock *sk = v;
1758
1759         if (v == SEQ_START_TOKEN) {
1760                 seq_puts(seq,
1761                          "  sl  "
1762                          "local_address                         "
1763                          "remote_address                        "
1764                          "st tx_queue rx_queue tr tm->when retrnsmt"
1765                          "   uid  timeout inode\n");
1766                 goto out;
1767         }
1768         st = seq->private;
1769
1770         switch (st->state) {
1771         case TCP_SEQ_STATE_LISTENING:
1772         case TCP_SEQ_STATE_ESTABLISHED:
1773                 if (sk->sk_state == TCP_TIME_WAIT)
1774                         get_timewait6_sock(seq, v, st->num);
1775                 else
1776                         get_tcp6_sock(seq, v, st->num);
1777                 break;
1778         case TCP_SEQ_STATE_OPENREQ:
1779                 get_openreq6(seq, v, st->num, st->uid);
1780                 break;
1781         }
1782 out:
1783         return 0;
1784 }
1785
1786 static const struct file_operations tcp6_afinfo_seq_fops = {
1787         .owner   = THIS_MODULE,
1788         .open    = tcp_seq_open,
1789         .read    = seq_read,
1790         .llseek  = seq_lseek,
1791         .release = seq_release_net
1792 };
1793
1794 static struct tcp_seq_afinfo tcp6_seq_afinfo = {
1795         .name           = "tcp6",
1796         .family         = AF_INET6,
1797         .seq_fops       = &tcp6_afinfo_seq_fops,
1798         .seq_ops        = {
1799                 .show           = tcp6_seq_show,
1800         },
1801 };
1802
1803 int __net_init tcp6_proc_init(struct net *net)
1804 {
1805         return tcp_proc_register(net, &tcp6_seq_afinfo);
1806 }
1807
1808 void tcp6_proc_exit(struct net *net)
1809 {
1810         tcp_proc_unregister(net, &tcp6_seq_afinfo);
1811 }
1812 #endif
1813
1814 static void tcp_v6_clear_sk(struct sock *sk, int size)
1815 {
1816         struct inet_sock *inet = inet_sk(sk);
1817
1818         /* we do not want to clear pinet6 field, because of RCU lookups */
1819         sk_prot_clear_nulls(sk, offsetof(struct inet_sock, pinet6));
1820
1821         size -= offsetof(struct inet_sock, pinet6) + sizeof(inet->pinet6);
1822         memset(&inet->pinet6 + 1, 0, size);
1823 }
1824
1825 struct proto tcpv6_prot = {
1826         .name                   = "TCPv6",
1827         .owner                  = THIS_MODULE,
1828         .close                  = tcp_close,
1829         .connect                = tcp_v6_connect,
1830         .disconnect             = tcp_disconnect,
1831         .accept                 = inet_csk_accept,
1832         .ioctl                  = tcp_ioctl,
1833         .init                   = tcp_v6_init_sock,
1834         .destroy                = tcp_v6_destroy_sock,
1835         .shutdown               = tcp_shutdown,
1836         .setsockopt             = tcp_setsockopt,
1837         .getsockopt             = tcp_getsockopt,
1838         .recvmsg                = tcp_recvmsg,
1839         .sendmsg                = tcp_sendmsg,
1840         .sendpage               = tcp_sendpage,
1841         .backlog_rcv            = tcp_v6_do_rcv,
1842         .release_cb             = tcp_release_cb,
1843         .hash                   = inet_hash,
1844         .unhash                 = inet_unhash,
1845         .get_port               = inet_csk_get_port,
1846         .enter_memory_pressure  = tcp_enter_memory_pressure,
1847         .stream_memory_free     = tcp_stream_memory_free,
1848         .sockets_allocated      = &tcp_sockets_allocated,
1849         .memory_allocated       = &tcp_memory_allocated,
1850         .memory_pressure        = &tcp_memory_pressure,
1851         .orphan_count           = &tcp_orphan_count,
1852         .sysctl_mem             = sysctl_tcp_mem,
1853         .sysctl_wmem            = sysctl_tcp_wmem,
1854         .sysctl_rmem            = sysctl_tcp_rmem,
1855         .max_header             = MAX_TCP_HEADER,
1856         .obj_size               = sizeof(struct tcp6_sock),
1857         .slab_flags             = SLAB_DESTROY_BY_RCU,
1858         .twsk_prot              = &tcp6_timewait_sock_ops,
1859         .rsk_prot               = &tcp6_request_sock_ops,
1860         .h.hashinfo             = &tcp_hashinfo,
1861         .no_autobind            = true,
1862 #ifdef CONFIG_COMPAT
1863         .compat_setsockopt      = compat_tcp_setsockopt,
1864         .compat_getsockopt      = compat_tcp_getsockopt,
1865 #endif
1866 #ifdef CONFIG_MEMCG_KMEM
1867         .proto_cgroup           = tcp_proto_cgroup,
1868 #endif
1869         .clear_sk               = tcp_v6_clear_sk,
1870 };
1871
1872 static const struct inet6_protocol tcpv6_protocol = {
1873         .early_demux    =       tcp_v6_early_demux,
1874         .handler        =       tcp_v6_rcv,
1875         .err_handler    =       tcp_v6_err,
1876         .flags          =       INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
1877 };
1878
1879 static struct inet_protosw tcpv6_protosw = {
1880         .type           =       SOCK_STREAM,
1881         .protocol       =       IPPROTO_TCP,
1882         .prot           =       &tcpv6_prot,
1883         .ops            =       &inet6_stream_ops,
1884         .flags          =       INET_PROTOSW_PERMANENT |
1885                                 INET_PROTOSW_ICSK,
1886 };
1887
1888 static int __net_init tcpv6_net_init(struct net *net)
1889 {
1890         return inet_ctl_sock_create(&net->ipv6.tcp_sk, PF_INET6,
1891                                     SOCK_RAW, IPPROTO_TCP, net);
1892 }
1893
1894 static void __net_exit tcpv6_net_exit(struct net *net)
1895 {
1896         inet_ctl_sock_destroy(net->ipv6.tcp_sk);
1897 }
1898
1899 static void __net_exit tcpv6_net_exit_batch(struct list_head *net_exit_list)
1900 {
1901         inet_twsk_purge(&tcp_hashinfo, &tcp_death_row, AF_INET6);
1902 }
1903
1904 static struct pernet_operations tcpv6_net_ops = {
1905         .init       = tcpv6_net_init,
1906         .exit       = tcpv6_net_exit,
1907         .exit_batch = tcpv6_net_exit_batch,
1908 };
1909
1910 int __init tcpv6_init(void)
1911 {
1912         int ret;
1913
1914         ret = inet6_add_protocol(&tcpv6_protocol, IPPROTO_TCP);
1915         if (ret)
1916                 goto out;
1917
1918         /* register inet6 protocol */
1919         ret = inet6_register_protosw(&tcpv6_protosw);
1920         if (ret)
1921                 goto out_tcpv6_protocol;
1922
1923         ret = register_pernet_subsys(&tcpv6_net_ops);
1924         if (ret)
1925                 goto out_tcpv6_protosw;
1926 out:
1927         return ret;
1928
1929 out_tcpv6_protosw:
1930         inet6_unregister_protosw(&tcpv6_protosw);
1931 out_tcpv6_protocol:
1932         inet6_del_protocol(&tcpv6_protocol, IPPROTO_TCP);
1933         goto out;
1934 }
1935
1936 void tcpv6_exit(void)
1937 {
1938         unregister_pernet_subsys(&tcpv6_net_ops);
1939         inet6_unregister_protosw(&tcpv6_protosw);
1940         inet6_del_protocol(&tcpv6_protocol, IPPROTO_TCP);
1941 }