net/ipv6/tcp_ipv6.c

   1 /*
   2  *      TCP over IPv6
   3  *      Linux INET6 implementation
   4  *
   5  *      Authors:
   6  *      Pedro Roque             <roque@di.fc.ul.pt>
   7  *
   8  *      Based on:
   9  *      linux/net/ipv4/tcp.c
  10  *      linux/net/ipv4/tcp_input.c
  11  *      linux/net/ipv4/tcp_output.c
  12  *
  13  *      Fixes:
  14  *      Hideaki YOSHIFUJI       :       sin6_scope_id support
  15  *      YOSHIFUJI Hideaki @USAGI and:   Support IPV6_V6ONLY socket option, which
  16  *      Alexey Kuznetsov                allow both IPv4 and IPv6 sockets to bind
  17  *                                      a single port at the same time.
  18  *      YOSHIFUJI Hideaki @USAGI:       convert /proc/net/tcp6 to seq_file.
  19  *
  20  *      This program is free software; you can redistribute it and/or
  21  *      modify it under the terms of the GNU General Public License
  22  *      as published by the Free Software Foundation; either version
  23  *      2 of the License, or (at your option) any later version.
  24  */
  25
  26 #include <linux/bottom_half.h>
  27 #include <linux/module.h>
  28 #include <linux/errno.h>
  29 #include <linux/types.h>
  30 #include <linux/socket.h>
  31 #include <linux/sockios.h>
  32 #include <linux/net.h>
  33 #include <linux/jiffies.h>
  34 #include <linux/in.h>
  35 #include <linux/in6.h>
  36 #include <linux/netdevice.h>
  37 #include <linux/init.h>
  38 #include <linux/jhash.h>
  39 #include <linux/ipsec.h>
  40 #include <linux/times.h>
  41 #include <linux/slab.h>
  42 #include <linux/uaccess.h>
  43 #include <linux/ipv6.h>
  44 #include <linux/icmpv6.h>
  45 #include <linux/random.h>
  46
  47 #include <net/tcp.h>
  48 #include <net/ndisc.h>
  49 #include <net/inet6_hashtables.h>
  50 #include <net/inet6_connection_sock.h>
  51 #include <net/ipv6.h>
  52 #include <net/transp_v6.h>
  53 #include <net/addrconf.h>
  54 #include <net/ip6_route.h>
  55 #include <net/ip6_checksum.h>
  56 #include <net/inet_ecn.h>
  57 #include <net/protocol.h>
  58 #include <net/xfrm.h>
  59 #include <net/snmp.h>
  60 #include <net/dsfield.h>
  61 #include <net/timewait_sock.h>
  62 #include <net/inet_common.h>
  63 #include <net/secure_seq.h>
  64 #include <net/busy_poll.h>
  65
  66 #include <linux/proc_fs.h>
  67 #include <linux/seq_file.h>
  68
  69 #include <crypto/hash.h>
  70 #include <linux/scatterlist.h>
  71
  72 static void     tcp_v6_send_reset(const struct sock *sk, struct sk_buff *skb);
  73 static void     tcp_v6_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb,
  74                                       struct request_sock *req);
  75
  76 static int      tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb);
  77
  78 static const struct inet_connection_sock_af_ops ipv6_mapped;
  79 static const struct inet_connection_sock_af_ops ipv6_specific;
  80 #ifdef CONFIG_TCP_MD5SIG
  81 static const struct tcp_sock_af_ops tcp_sock_ipv6_specific;
  82 static const struct tcp_sock_af_ops tcp_sock_ipv6_mapped_specific;
  83 #else
  84 static struct tcp_md5sig_key *tcp_v6_md5_do_lookup(const struct sock *sk,
  85                                                    const struct in6_addr *addr)
  86 {
  87         return NULL;
  88 }
  89 #endif
  90
  91 static void inet6_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb)
  92 {
  93         struct dst_entry *dst = skb_dst(skb);
  94
  95         if (dst && dst_hold_safe(dst)) {
  96                 const struct rt6_info *rt = (const struct rt6_info *)dst;
  97
  98                 sk->sk_rx_dst = dst;
  99                 inet_sk(sk)->rx_dst_ifindex = skb->skb_iif;
 100                 inet6_sk(sk)->rx_dst_cookie = rt6_get_cookie(rt);
 101         }
 102 }
 103
 104 static __u32 tcp_v6_init_sequence(const struct sk_buff *skb)
 105 {
 106         return secure_tcpv6_sequence_number(ipv6_hdr(skb)->daddr.s6_addr32,
 107                                             ipv6_hdr(skb)->saddr.s6_addr32,
 108                                             tcp_hdr(skb)->dest,
 109                                             tcp_hdr(skb)->source);
 110 }
 111
 112 static int tcp_v6_connect(struct sock *sk, struct sockaddr *uaddr,
 113                           int addr_len)
 114 {
 115         struct sockaddr_in6 *usin = (struct sockaddr_in6 *) uaddr;
 116         struct inet_sock *inet = inet_sk(sk);
 117         struct inet_connection_sock *icsk = inet_csk(sk);
 118         struct ipv6_pinfo *np = inet6_sk(sk);
 119         struct tcp_sock *tp = tcp_sk(sk);
 120         struct in6_addr *saddr = NULL, *final_p, final;
 121         struct ipv6_txoptions *opt;
 122         struct flowi6 fl6;
 123         struct dst_entry *dst;
 124         int addr_type;
 125         int err;
 126
 127         if (addr_len < SIN6_LEN_RFC2133)
 128                 return -EINVAL;
 129
 130         if (usin->sin6_family != AF_INET6)
 131                 return -EAFNOSUPPORT;
 132
 133         memset(&fl6, 0, sizeof(fl6));
 134
 135         if (np->sndflow) {
 136                 fl6.flowlabel = usin->sin6_flowinfo&IPV6_FLOWINFO_MASK;
 137                 IP6_ECN_flow_init(fl6.flowlabel);
 138                 if (fl6.flowlabel&IPV6_FLOWLABEL_MASK) {
 139                         struct ip6_flowlabel *flowlabel;
 140                         flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
 141                         if (!flowlabel)
 142                                 return -EINVAL;
 143                         fl6_sock_release(flowlabel);
 144                 }
 145         }
 146
 147         /*
 148          *      connect() to INADDR_ANY means loopback (BSD'ism).
 149          */
 150
 151         if (ipv6_addr_any(&usin->sin6_addr))
 152                 usin->sin6_addr.s6_addr[15] = 0x1;
 153
 154         addr_type = ipv6_addr_type(&usin->sin6_addr);
 155
 156         if (addr_type & IPV6_ADDR_MULTICAST)
 157                 return -ENETUNREACH;
 158
 159         if (addr_type&IPV6_ADDR_LINKLOCAL) {
 160                 if (addr_len >= sizeof(struct sockaddr_in6) &&
 161                     usin->sin6_scope_id) {
 162                         /* If interface is set while binding, indices
 163                          * must coincide.
 164                          */
 165                         if (sk->sk_bound_dev_if &&
 166                             sk->sk_bound_dev_if != usin->sin6_scope_id)
 167                                 return -EINVAL;
 168
 169                         sk->sk_bound_dev_if = usin->sin6_scope_id;
 170                 }
 171
 172                 /* Connect to link-local address requires an interface */
 173                 if (!sk->sk_bound_dev_if)
 174                         return -EINVAL;
 175         }
 176
 177         if (tp->rx_opt.ts_recent_stamp &&
 178             !ipv6_addr_equal(&sk->sk_v6_daddr, &usin->sin6_addr)) {
 179                 tp->rx_opt.ts_recent = 0;
 180                 tp->rx_opt.ts_recent_stamp = 0;
 181                 tp->write_seq = 0;
 182         }
 183
 184         sk->sk_v6_daddr = usin->sin6_addr;
 185         np->flow_label = fl6.flowlabel;
 186
 187         /*
 188          *      TCP over IPv4
 189          */
 190
 191         if (addr_type == IPV6_ADDR_MAPPED) {
 192                 u32 exthdrlen = icsk->icsk_ext_hdr_len;
 193                 struct sockaddr_in sin;
 194
 195                 SOCK_DEBUG(sk, "connect: ipv4 mapped\n");
 196
 197                 if (__ipv6_only_sock(sk))
 198                         return -ENETUNREACH;
 199
 200                 sin.sin_family = AF_INET;
 201                 sin.sin_port = usin->sin6_port;
 202                 sin.sin_addr.s_addr = usin->sin6_addr.s6_addr32[3];
 203
 204                 icsk->icsk_af_ops = &ipv6_mapped;
 205                 sk->sk_backlog_rcv = tcp_v4_do_rcv;
 206 #ifdef CONFIG_TCP_MD5SIG
 207                 tp->af_specific = &tcp_sock_ipv6_mapped_specific;
 208 #endif
 209
 210                 err = tcp_v4_connect(sk, (struct sockaddr *)&sin, sizeof(sin));
 211
 212                 if (err) {
 213                         icsk->icsk_ext_hdr_len = exthdrlen;
 214                         icsk->icsk_af_ops = &ipv6_specific;
 215                         sk->sk_backlog_rcv = tcp_v6_do_rcv;
 216 #ifdef CONFIG_TCP_MD5SIG
 217                         tp->af_specific = &tcp_sock_ipv6_specific;
 218 #endif
 219                         goto failure;
 220                 }
 221                 np->saddr = sk->sk_v6_rcv_saddr;
 222
 223                 return err;
 224         }
 225
 226         if (!ipv6_addr_any(&sk->sk_v6_rcv_saddr))
 227                 saddr = &sk->sk_v6_rcv_saddr;
 228
 229         fl6.flowi6_proto = IPPROTO_TCP;
 230         fl6.daddr = sk->sk_v6_daddr;
 231         fl6.saddr = saddr ? *saddr : np->saddr;
 232         fl6.flowi6_oif = sk->sk_bound_dev_if;
 233         fl6.flowi6_mark = sk->sk_mark;
 234         fl6.fl6_dport = usin->sin6_port;
 235         fl6.fl6_sport = inet->inet_sport;
 236
 237         opt = rcu_dereference_protected(np->opt, sock_owned_by_user(sk));
 238         final_p = fl6_update_dst(&fl6, opt, &final);
 239
 240         security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));
 241
 242         dst = ip6_dst_lookup_flow(sk, &fl6, final_p);
 243         if (IS_ERR(dst)) {
 244                 err = PTR_ERR(dst);
 245                 goto failure;
 246         }
 247
 248         if (!saddr) {
 249                 saddr = &fl6.saddr;
 250                 sk->sk_v6_rcv_saddr = *saddr;
 251         }
 252
 253         /* set the source address */
 254         np->saddr = *saddr;
 255         inet->inet_rcv_saddr = LOOPBACK4_IPV6;
 256
 257         sk->sk_gso_type = SKB_GSO_TCPV6;
 258         ip6_dst_store(sk, dst, NULL, NULL);
 259
 260         if (tcp_death_row.sysctl_tw_recycle &&
 261             !tp->rx_opt.ts_recent_stamp &&
 262             ipv6_addr_equal(&fl6.daddr, &sk->sk_v6_daddr))
 263                 tcp_fetch_timewait_stamp(sk, dst);
 264
 265         icsk->icsk_ext_hdr_len = 0;
 266         if (opt)
 267                 icsk->icsk_ext_hdr_len = opt->opt_flen +
 268                                          opt->opt_nflen;
 269
 270         tp->rx_opt.mss_clamp = IPV6_MIN_MTU - sizeof(struct tcphdr) - sizeof(struct ipv6hdr);
 271
 272         inet->inet_dport = usin->sin6_port;
 273
 274         tcp_set_state(sk, TCP_SYN_SENT);
 275         err = inet6_hash_connect(&tcp_death_row, sk);
 276         if (err)
 277                 goto late_failure;
 278
 279         sk_set_txhash(sk);
 280
 281         if (!tp->write_seq && likely(!tp->repair))
 282                 tp->write_seq = secure_tcpv6_sequence_number(np->saddr.s6_addr32,
 283                                                              sk->sk_v6_daddr.s6_addr32,
 284                                                              inet->inet_sport,
 285                                                              inet->inet_dport);
 286
 287         err = tcp_connect(sk);
 288         if (err)
 289                 goto late_failure;
 290
 291         return 0;
 292
 293 late_failure:
 294         tcp_set_state(sk, TCP_CLOSE);
 295         __sk_dst_reset(sk);
 296 failure:
 297         inet->inet_dport = 0;
 298         sk->sk_route_caps = 0;
 299         return err;
 300 }
 301
 302 static void tcp_v6_mtu_reduced(struct sock *sk)
 303 {
 304         struct dst_entry *dst;
 305
 306         if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE))
 307                 return;
 308
 309         dst = inet6_csk_update_pmtu(sk, tcp_sk(sk)->mtu_info);
 310         if (!dst)
 311                 return;
 312
 313         if (inet_csk(sk)->icsk_pmtu_cookie > dst_mtu(dst)) {
 314                 tcp_sync_mss(sk, dst_mtu(dst));
 315                 tcp_simple_retransmit(sk);
 316         }
 317 }
 318
 319 static void tcp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 320                 u8 type, u8 code, int offset, __be32 info)
 321 {
 322         const struct ipv6hdr *hdr = (const struct ipv6hdr *)skb->data;
 323         const struct tcphdr *th = (struct tcphdr *)(skb->data+offset);
 324         struct net *net = dev_net(skb->dev);
 325         struct request_sock *fastopen;
 326         struct ipv6_pinfo *np;
 327         struct tcp_sock *tp;
 328         __u32 seq, snd_una;
 329         struct sock *sk;
 330         bool fatal;
 331         int err;
 332
 333         sk = __inet6_lookup_established(net, &tcp_hashinfo,
 334                                         &hdr->daddr, th->dest,
 335                                         &hdr->saddr, ntohs(th->source),
 336                                         skb->dev->ifindex);
 337
 338         if (!sk) {
 339                 ICMP6_INC_STATS_BH(net, __in6_dev_get(skb->dev),
 340                                    ICMP6_MIB_INERRORS);
 341                 return;
 342         }
 343
 344         if (sk->sk_state == TCP_TIME_WAIT) {
 345                 inet_twsk_put(inet_twsk(sk));
 346                 return;
 347         }
 348         seq = ntohl(th->seq);
 349         fatal = icmpv6_err_convert(type, code, &err);
 350         if (sk->sk_state == TCP_NEW_SYN_RECV)
 351                 return tcp_req_err(sk, seq, fatal);
 352
 353         bh_lock_sock(sk);
 354         if (sock_owned_by_user(sk) && type != ICMPV6_PKT_TOOBIG)
 355                 NET_INC_STATS_BH(net, LINUX_MIB_LOCKDROPPEDICMPS);
 356
 357         if (sk->sk_state == TCP_CLOSE)
 358                 goto out;
 359
 360         if (ipv6_hdr(skb)->hop_limit < inet6_sk(sk)->min_hopcount) {
 361                 NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP);
 362                 goto out;
 363         }
 364
 365         tp = tcp_sk(sk);
 366         /* XXX (TFO) - tp->snd_una should be ISN (tcp_create_openreq_child() */
 367         fastopen = tp->fastopen_rsk;
 368         snd_una = fastopen ? tcp_rsk(fastopen)->snt_isn : tp->snd_una;
 369         if (sk->sk_state != TCP_LISTEN &&
 370             !between(seq, snd_una, tp->snd_nxt)) {
 371                 NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
 372                 goto out;
 373         }
 374
 375         np = inet6_sk(sk);
 376
 377         if (type == NDISC_REDIRECT) {
 378                 struct dst_entry *dst = __sk_dst_check(sk, np->dst_cookie);
 379
 380                 if (dst)
 381                         dst->ops->redirect(dst, sk, skb);
 382                 goto out;
 383         }
 384
 385         if (type == ICMPV6_PKT_TOOBIG) {
 386                 /* We are not interested in TCP_LISTEN and open_requests
 387                  * (SYN-ACKs send out by Linux are always <576bytes so
 388                  * they should go through unfragmented).
 389                  */
 390                 if (sk->sk_state == TCP_LISTEN)
 391                         goto out;
 392
 393                 if (!ip6_sk_accept_pmtu(sk))
 394                         goto out;
 395
 396                 tp->mtu_info = ntohl(info);
 397                 if (!sock_owned_by_user(sk))
 398                         tcp_v6_mtu_reduced(sk);
 399                 else if (!test_and_set_bit(TCP_MTU_REDUCED_DEFERRED,
 400                                            &tp->tsq_flags))
 401                         sock_hold(sk);
 402                 goto out;
 403         }
 404
 405
 406         /* Might be for an request_sock */
 407         switch (sk->sk_state) {
 408         case TCP_SYN_SENT:
 409         case TCP_SYN_RECV:
 410                 /* Only in fast or simultaneous open. If a fast open socket is
 411                  * is already accepted it is treated as a connected one below.
 412                  */
 413                 if (fastopen && !fastopen->sk)
 414                         break;
 415
 416                 if (!sock_owned_by_user(sk)) {
 417                         sk->sk_err = err;
 418                         sk->sk_error_report(sk);                /* Wake people up to see the error (see connect in sock.c) */
 419
 420                         tcp_done(sk);
 421                 } else
 422                         sk->sk_err_soft = err;
 423                 goto out;
 424         }
 425
 426         if (!sock_owned_by_user(sk) && np->recverr) {
 427                 sk->sk_err = err;
 428                 sk->sk_error_report(sk);
 429         } else
 430                 sk->sk_err_soft = err;
 431
 432 out:
 433         bh_unlock_sock(sk);
 434         sock_put(sk);
 435 }
 436
 437
 438 static int tcp_v6_send_synack(const struct sock *sk, struct dst_entry *dst,
 439                               struct flowi *fl,
 440                               struct request_sock *req,
 441                               struct tcp_fastopen_cookie *foc,
 442                               bool attach_req)
 443 {
 444         struct inet_request_sock *ireq = inet_rsk(req);
 445         struct ipv6_pinfo *np = inet6_sk(sk);
 446         struct flowi6 *fl6 = &fl->u.ip6;
 447         struct sk_buff *skb;
 448         int err = -ENOMEM;
 449
 450         /* First, grab a route. */
 451         if (!dst && (dst = inet6_csk_route_req(sk, fl6, req,
 452                                                IPPROTO_TCP)) == NULL)
 453                 goto done;
 454
 455         skb = tcp_make_synack(sk, dst, req, foc, attach_req);
 456
 457         if (skb) {
 458                 __tcp_v6_send_check(skb, &ireq->ir_v6_loc_addr,
 459                                     &ireq->ir_v6_rmt_addr);
 460
 461                 fl6->daddr = ireq->ir_v6_rmt_addr;
 462                 if (np->repflow && ireq->pktopts)
 463                         fl6->flowlabel = ip6_flowlabel(ipv6_hdr(ireq->pktopts));
 464
 465                 rcu_read_lock();
 466                 err = ip6_xmit(sk, skb, fl6, rcu_dereference(np->opt),
 467                                np->tclass);
 468                 rcu_read_unlock();
 469                 err = net_xmit_eval(err);
 470         }
 471
 472 done:
 473         return err;
 474 }
 475
 476
 477 static void tcp_v6_reqsk_destructor(struct request_sock *req)
 478 {
 479         kfree_skb(inet_rsk(req)->pktopts);
 480 }
 481
 482 #ifdef CONFIG_TCP_MD5SIG
 483 static struct tcp_md5sig_key *tcp_v6_md5_do_lookup(const struct sock *sk,
 484                                                    const struct in6_addr *addr)
 485 {
 486         return tcp_md5_do_lookup(sk, (union tcp_md5_addr *)addr, AF_INET6);
 487 }
 488
 489 static struct tcp_md5sig_key *tcp_v6_md5_lookup(const struct sock *sk,
 490                                                 const struct sock *addr_sk)
 491 {
 492         return tcp_v6_md5_do_lookup(sk, &addr_sk->sk_v6_daddr);
 493 }
 494
 495 static int tcp_v6_parse_md5_keys(struct sock *sk, char __user *optval,
 496                                  int optlen)
 497 {
 498         struct tcp_md5sig cmd;
 499         struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)&cmd.tcpm_addr;
 500
 501         if (optlen < sizeof(cmd))
 502                 return -EINVAL;
 503
 504         if (copy_from_user(&cmd, optval, sizeof(cmd)))
 505                 return -EFAULT;
 506
 507         if (sin6->sin6_family != AF_INET6)
 508                 return -EINVAL;
 509
 510         if (!cmd.tcpm_keylen) {
 511                 if (ipv6_addr_v4mapped(&sin6->sin6_addr))
 512                         return tcp_md5_do_del(sk, (union tcp_md5_addr *)&sin6->sin6_addr.s6_addr32[3],
 513                                               AF_INET);
 514                 return tcp_md5_do_del(sk, (union tcp_md5_addr *)&sin6->sin6_addr,
 515                                       AF_INET6);
 516         }
 517
 518         if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN)
 519                 return -EINVAL;
 520
 521         if (ipv6_addr_v4mapped(&sin6->sin6_addr))
 522                 return tcp_md5_do_add(sk, (union tcp_md5_addr *)&sin6->sin6_addr.s6_addr32[3],
 523                                       AF_INET, cmd.tcpm_key, cmd.tcpm_keylen, GFP_KERNEL);
 524
 525         return tcp_md5_do_add(sk, (union tcp_md5_addr *)&sin6->sin6_addr,
 526                               AF_INET6, cmd.tcpm_key, cmd.tcpm_keylen, GFP_KERNEL);
 527 }
 528
 529 static int tcp_v6_md5_hash_pseudoheader(struct tcp_md5sig_pool *hp,
 530                                         const struct in6_addr *daddr,
 531                                         const struct in6_addr *saddr, int nbytes)
 532 {
 533         struct tcp6_pseudohdr *bp;
 534         struct scatterlist sg;
 535
 536         bp = &hp->md5_blk.ip6;
 537         /* 1. TCP pseudo-header (RFC2460) */
 538         bp->saddr = *saddr;
 539         bp->daddr = *daddr;
 540         bp->protocol = cpu_to_be32(IPPROTO_TCP);
 541         bp->len = cpu_to_be32(nbytes);
 542
 543         sg_init_one(&sg, bp, sizeof(*bp));
 544         ahash_request_set_crypt(hp->md5_req, &sg, NULL, sizeof(*bp));
 545         return crypto_ahash_update(hp->md5_req);
 546 }
 547
 548 static int tcp_v6_md5_hash_hdr(char *md5_hash, struct tcp_md5sig_key *key,
 549                                const struct in6_addr *daddr, struct in6_addr *saddr,
 550                                const struct tcphdr *th)
 551 {
 552         struct tcp_md5sig_pool *hp;
 553         struct ahash_request *req;
 554
 555         hp = tcp_get_md5sig_pool();
 556         if (!hp)
 557                 goto clear_hash_noput;
 558         req = hp->md5_req;
 559
 560         if (crypto_ahash_init(req))
 561                 goto clear_hash;
 562         if (tcp_v6_md5_hash_pseudoheader(hp, daddr, saddr, th->doff << 2))
 563                 goto clear_hash;
 564         if (tcp_md5_hash_header(hp, th))
 565                 goto clear_hash;
 566         if (tcp_md5_hash_key(hp, key))
 567                 goto clear_hash;
 568         ahash_request_set_crypt(req, NULL, md5_hash, 0);
 569         if (crypto_ahash_final(req))
 570                 goto clear_hash;
 571
 572         tcp_put_md5sig_pool();
 573         return 0;
 574
 575 clear_hash:
 576         tcp_put_md5sig_pool();
 577 clear_hash_noput:
 578         memset(md5_hash, 0, 16);
 579         return 1;
 580 }
 581
 582 static int tcp_v6_md5_hash_skb(char *md5_hash,
 583                                const struct tcp_md5sig_key *key,
 584                                const struct sock *sk,
 585                                const struct sk_buff *skb)
 586 {
 587         const struct in6_addr *saddr, *daddr;
 588         struct tcp_md5sig_pool *hp;
 589         struct ahash_request *req;
 590         const struct tcphdr *th = tcp_hdr(skb);
 591
 592         if (sk) { /* valid for establish/request sockets */
 593                 saddr = &sk->sk_v6_rcv_saddr;
 594                 daddr = &sk->sk_v6_daddr;
 595         } else {
 596                 const struct ipv6hdr *ip6h = ipv6_hdr(skb);
 597                 saddr = &ip6h->saddr;
 598                 daddr = &ip6h->daddr;
 599         }
 600
 601         hp = tcp_get_md5sig_pool();
 602         if (!hp)
 603                 goto clear_hash_noput;
 604         req = hp->md5_req;
 605
 606         if (crypto_ahash_init(req))
 607                 goto clear_hash;
 608
 609         if (tcp_v6_md5_hash_pseudoheader(hp, daddr, saddr, skb->len))
 610                 goto clear_hash;
 611         if (tcp_md5_hash_header(hp, th))
 612                 goto clear_hash;
 613         if (tcp_md5_hash_skb_data(hp, skb, th->doff << 2))
 614                 goto clear_hash;
 615         if (tcp_md5_hash_key(hp, key))
 616                 goto clear_hash;
 617         ahash_request_set_crypt(req, NULL, md5_hash, 0);
 618         if (crypto_ahash_final(req))
 619                 goto clear_hash;
 620
 621         tcp_put_md5sig_pool();
 622         return 0;
 623
 624 clear_hash:
 625         tcp_put_md5sig_pool();
 626 clear_hash_noput:
 627         memset(md5_hash, 0, 16);
 628         return 1;
 629 }
 630
 631 #endif
 632
 633 static bool tcp_v6_inbound_md5_hash(const struct sock *sk,
 634                                     const struct sk_buff *skb)
 635 {
 636 #ifdef CONFIG_TCP_MD5SIG
 637         const __u8 *hash_location = NULL;
 638         struct tcp_md5sig_key *hash_expected;
 639         const struct ipv6hdr *ip6h = ipv6_hdr(skb);
 640         const struct tcphdr *th = tcp_hdr(skb);
 641         int genhash;
 642         u8 newhash[16];
 643
 644         hash_expected = tcp_v6_md5_do_lookup(sk, &ip6h->saddr);
 645         hash_location = tcp_parse_md5sig_option(th);
 646
 647         /* We've parsed the options - do we have a hash? */
 648         if (!hash_expected && !hash_location)
 649                 return false;
 650
 651         if (hash_expected && !hash_location) {
 652                 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5NOTFOUND);
 653                 return true;
 654         }
 655
 656         if (!hash_expected && hash_location) {
 657                 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5UNEXPECTED);
 658                 return true;
 659         }
 660
 661         /* check the signature */
 662         genhash = tcp_v6_md5_hash_skb(newhash,
 663                                       hash_expected,
 664                                       NULL, skb);
 665
 666         if (genhash || memcmp(hash_location, newhash, 16) != 0) {
 667                 net_info_ratelimited("MD5 Hash %s for [%pI6c]:%u->[%pI6c]:%u\n",
 668                                      genhash ? "failed" : "mismatch",
 669                                      &ip6h->saddr, ntohs(th->source),
 670                                      &ip6h->daddr, ntohs(th->dest));
 671                 return true;
 672         }
 673 #endif
 674         return false;
 675 }
 676
 677 static void tcp_v6_init_req(struct request_sock *req,
 678                             const struct sock *sk_listener,
 679                             struct sk_buff *skb)
 680 {
 681         struct inet_request_sock *ireq = inet_rsk(req);
 682         const struct ipv6_pinfo *np = inet6_sk(sk_listener);
 683
 684         ireq->ir_v6_rmt_addr = ipv6_hdr(skb)->saddr;
 685         ireq->ir_v6_loc_addr = ipv6_hdr(skb)->daddr;
 686
 687         /* So that link locals have meaning */
 688         if (!sk_listener->sk_bound_dev_if &&
 689             ipv6_addr_type(&ireq->ir_v6_rmt_addr) & IPV6_ADDR_LINKLOCAL)
 690                 ireq->ir_iif = tcp_v6_iif(skb);
 691
 692         if (!TCP_SKB_CB(skb)->tcp_tw_isn &&
 693             (ipv6_opt_accepted(sk_listener, skb, &TCP_SKB_CB(skb)->header.h6) ||
 694              np->rxopt.bits.rxinfo ||
 695              np->rxopt.bits.rxoinfo || np->rxopt.bits.rxhlim ||
 696              np->rxopt.bits.rxohlim || np->repflow)) {
 697                 atomic_inc(&skb->users);
 698                 ireq->pktopts = skb;
 699         }
 700 }
 701
 702 static struct dst_entry *tcp_v6_route_req(const struct sock *sk,
 703                                           struct flowi *fl,
 704                                           const struct request_sock *req,
 705                                           bool *strict)
 706 {
 707         if (strict)
 708                 *strict = true;
 709         return inet6_csk_route_req(sk, &fl->u.ip6, req, IPPROTO_TCP);
 710 }
 711
 712 struct request_sock_ops tcp6_request_sock_ops __read_mostly = {
 713         .family         =       AF_INET6,
 714         .obj_size       =       sizeof(struct tcp6_request_sock),
 715         .rtx_syn_ack    =       tcp_rtx_synack,
 716         .send_ack       =       tcp_v6_reqsk_send_ack,
 717         .destructor     =       tcp_v6_reqsk_destructor,
 718         .send_reset     =       tcp_v6_send_reset,
 719         .syn_ack_timeout =      tcp_syn_ack_timeout,
 720 };
 721
 722 static const struct tcp_request_sock_ops tcp_request_sock_ipv6_ops = {
 723         .mss_clamp      =       IPV6_MIN_MTU - sizeof(struct tcphdr) -
 724                                 sizeof(struct ipv6hdr),
 725 #ifdef CONFIG_TCP_MD5SIG
 726         .req_md5_lookup =       tcp_v6_md5_lookup,
 727         .calc_md5_hash  =       tcp_v6_md5_hash_skb,
 728 #endif
 729         .init_req       =       tcp_v6_init_req,
 730 #ifdef CONFIG_SYN_COOKIES
 731         .cookie_init_seq =      cookie_v6_init_sequence,
 732 #endif
 733         .route_req      =       tcp_v6_route_req,
 734         .init_seq       =       tcp_v6_init_sequence,
 735         .send_synack    =       tcp_v6_send_synack,
 736 };
 737
 738 static void tcp_v6_send_response(const struct sock *sk, struct sk_buff *skb, u32 seq,
 739                                  u32 ack, u32 win, u32 tsval, u32 tsecr,
 740                                  int oif, struct tcp_md5sig_key *key, int rst,
 741                                  u8 tclass, u32 label)
 742 {
 743         const struct tcphdr *th = tcp_hdr(skb);
 744         struct tcphdr *t1;
 745         struct sk_buff *buff;
 746         struct flowi6 fl6;
 747         struct net *net = sk ? sock_net(sk) : dev_net(skb_dst(skb)->dev);
 748         struct sock *ctl_sk = net->ipv6.tcp_sk;
 749         unsigned int tot_len = sizeof(struct tcphdr);
 750         struct dst_entry *dst;
 751         __be32 *topt;
 752
 753         if (tsecr)
 754                 tot_len += TCPOLEN_TSTAMP_ALIGNED;
 755 #ifdef CONFIG_TCP_MD5SIG
 756         if (key)
 757                 tot_len += TCPOLEN_MD5SIG_ALIGNED;
 758 #endif
 759
 760         buff = alloc_skb(MAX_HEADER + sizeof(struct ipv6hdr) + tot_len,
 761                          GFP_ATOMIC);
 762         if (!buff)
 763                 return;
 764
 765         skb_reserve(buff, MAX_HEADER + sizeof(struct ipv6hdr) + tot_len);
 766
 767         t1 = (struct tcphdr *) skb_push(buff, tot_len);
 768         skb_reset_transport_header(buff);
 769
 770         /* Swap the send and the receive. */
 771         memset(t1, 0, sizeof(*t1));
 772         t1->dest = th->source;
 773         t1->source = th->dest;
 774         t1->doff = tot_len / 4;
 775         t1->seq = htonl(seq);
 776         t1->ack_seq = htonl(ack);
 777         t1->ack = !rst || !th->ack;
 778         t1->rst = rst;
 779         t1->window = htons(win);
 780
 781         topt = (__be32 *)(t1 + 1);
 782
 783         if (tsecr) {
 784                 *topt++ = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
 785                                 (TCPOPT_TIMESTAMP << 8) | TCPOLEN_TIMESTAMP);
 786                 *topt++ = htonl(tsval);
 787                 *topt++ = htonl(tsecr);
 788         }
 789
 790 #ifdef CONFIG_TCP_MD5SIG
 791         if (key) {
 792                 *topt++ = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
 793                                 (TCPOPT_MD5SIG << 8) | TCPOLEN_MD5SIG);
 794                 tcp_v6_md5_hash_hdr((__u8 *)topt, key,
 795                                     &ipv6_hdr(skb)->saddr,
 796                                     &ipv6_hdr(skb)->daddr, t1);
 797         }
 798 #endif
 799
 800         memset(&fl6, 0, sizeof(fl6));
 801         fl6.daddr = ipv6_hdr(skb)->saddr;
 802         fl6.saddr = ipv6_hdr(skb)->daddr;
 803         fl6.flowlabel = label;
 804
 805         buff->ip_summed = CHECKSUM_PARTIAL;
 806         buff->csum = 0;
 807
 808         __tcp_v6_send_check(buff, &fl6.saddr, &fl6.daddr);
 809
 810         fl6.flowi6_proto = IPPROTO_TCP;
 811         if (rt6_need_strict(&fl6.daddr) && !oif)
 812                 fl6.flowi6_oif = tcp_v6_iif(skb);
 813         else {
 814                 if (!oif && netif_index_is_l3_master(net, skb->skb_iif))
 815                         oif = skb->skb_iif;
 816
 817                 fl6.flowi6_oif = oif;
 818         }
 819
 820         fl6.flowi6_mark = IP6_REPLY_MARK(net, skb->mark);
 821         fl6.fl6_dport = t1->dest;
 822         fl6.fl6_sport = t1->source;
 823         security_skb_classify_flow(skb, flowi6_to_flowi(&fl6));
 824
 825         /* Pass a socket to ip6_dst_lookup either it is for RST
 826          * Underlying function will use this to retrieve the network
 827          * namespace
 828          */
 829         dst = ip6_dst_lookup_flow(ctl_sk, &fl6, NULL);
 830         if (!IS_ERR(dst)) {
 831                 skb_dst_set(buff, dst);
 832                 ip6_xmit(ctl_sk, buff, &fl6, NULL, tclass);
 833                 TCP_INC_STATS_BH(net, TCP_MIB_OUTSEGS);
 834                 if (rst)
 835                         TCP_INC_STATS_BH(net, TCP_MIB_OUTRSTS);
 836                 return;
 837         }
 838
 839         kfree_skb(buff);
 840 }
 841
 842 static void tcp_v6_send_reset(const struct sock *sk, struct sk_buff *skb)
 843 {
 844         const struct tcphdr *th = tcp_hdr(skb);
 845         u32 seq = 0, ack_seq = 0;
 846         struct tcp_md5sig_key *key = NULL;
 847 #ifdef CONFIG_TCP_MD5SIG
 848         const __u8 *hash_location = NULL;
 849         struct ipv6hdr *ipv6h = ipv6_hdr(skb);
 850         unsigned char newhash[16];
 851         int genhash;
 852         struct sock *sk1 = NULL;
 853 #endif
 854         int oif;
 855
 856         if (th->rst)
 857                 return;
 858
 859         /* If sk not NULL, it means we did a successful lookup and incoming
 860          * route had to be correct. prequeue might have dropped our dst.
 861          */
 862         if (!sk && !ipv6_unicast_destination(skb))
 863                 return;
 864
 865 #ifdef CONFIG_TCP_MD5SIG
 866         hash_location = tcp_parse_md5sig_option(th);
 867         if (sk && sk_fullsock(sk)) {
 868                 key = tcp_v6_md5_do_lookup(sk, &ipv6h->saddr);
 869         } else if (hash_location) {
 870                 /*
 871                  * active side is lost. Try to find listening socket through
 872                  * source port, and then find md5 key through listening socket.
 873                  * we are not loose security here:
 874                  * Incoming packet is checked with md5 hash with finding key,
 875                  * no RST generated if md5 hash doesn't match.
 876                  */
 877                 sk1 = inet6_lookup_listener(dev_net(skb_dst(skb)->dev),
 878                                            &tcp_hashinfo, NULL, 0,
 879                                            &ipv6h->saddr,
 880                                            th->source, &ipv6h->daddr,
 881                                            ntohs(th->source), tcp_v6_iif(skb));
 882                 if (!sk1)
 883                         return;
 884
 885                 rcu_read_lock();
 886                 key = tcp_v6_md5_do_lookup(sk1, &ipv6h->saddr);
 887                 if (!key)
 888                         goto release_sk1;
 889
 890                 genhash = tcp_v6_md5_hash_skb(newhash, key, NULL, skb);
 891                 if (genhash || memcmp(hash_location, newhash, 16) != 0)
 892                         goto release_sk1;
 893         }
 894 #endif
 895
 896         if (th->ack)
 897                 seq = ntohl(th->ack_seq);
 898         else
 899                 ack_seq = ntohl(th->seq) + th->syn + th->fin + skb->len -
 900                           (th->doff << 2);
 901
 902         oif = sk ? sk->sk_bound_dev_if : 0;
 903         tcp_v6_send_response(sk, skb, seq, ack_seq, 0, 0, 0, oif, key, 1, 0, 0);
 904
 905 #ifdef CONFIG_TCP_MD5SIG
 906 release_sk1:
 907         if (sk1) {
 908                 rcu_read_unlock();
 909                 sock_put(sk1);
 910         }
 911 #endif
 912 }
 913
 914 static void tcp_v6_send_ack(const struct sock *sk, struct sk_buff *skb, u32 seq,
 915                             u32 ack, u32 win, u32 tsval, u32 tsecr, int oif,
 916                             struct tcp_md5sig_key *key, u8 tclass,
 917                             u32 label)
 918 {
 919         tcp_v6_send_response(sk, skb, seq, ack, win, tsval, tsecr, oif, key, 0,
 920                              tclass, label);
 921 }
 922
 923 static void tcp_v6_timewait_ack(struct sock *sk, struct sk_buff *skb)
 924 {
 925         struct inet_timewait_sock *tw = inet_twsk(sk);
 926         struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
 927
 928         tcp_v6_send_ack(sk, skb, tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
 929                         tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
 930                         tcp_time_stamp + tcptw->tw_ts_offset,
 931                         tcptw->tw_ts_recent, tw->tw_bound_dev_if, tcp_twsk_md5_key(tcptw),
 932                         tw->tw_tclass, cpu_to_be32(tw->tw_flowlabel));
 933
 934         inet_twsk_put(tw);
 935 }
 936
 937 static void tcp_v6_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb,
 938                                   struct request_sock *req)
 939 {
 940         /* sk->sk_state == TCP_LISTEN -> for regular TCP_SYN_RECV
 941          * sk->sk_state == TCP_SYN_RECV -> for Fast Open.
 942          */
 943         tcp_v6_send_ack(sk, skb, (sk->sk_state == TCP_LISTEN) ?
 944                         tcp_rsk(req)->snt_isn + 1 : tcp_sk(sk)->snd_nxt,
 945                         tcp_rsk(req)->rcv_nxt, req->rsk_rcv_wnd,
 946                         tcp_time_stamp, req->ts_recent, sk->sk_bound_dev_if,
 947                         tcp_v6_md5_do_lookup(sk, &ipv6_hdr(skb)->daddr),
 948                         0, 0);
 949 }
 950
 951
 952 static struct sock *tcp_v6_cookie_check(struct sock *sk, struct sk_buff *skb)
 953 {
 954 #ifdef CONFIG_SYN_COOKIES
 955         const struct tcphdr *th = tcp_hdr(skb);
 956
 957         if (!th->syn)
 958                 sk = cookie_v6_check(sk, skb);
 959 #endif
 960         return sk;
 961 }
 962
 963 static int tcp_v6_conn_request(struct sock *sk, struct sk_buff *skb)
 964 {
 965         if (skb->protocol == htons(ETH_P_IP))
 966                 return tcp_v4_conn_request(sk, skb);
 967
 968         if (!ipv6_unicast_destination(skb))
 969                 goto drop;
 970
 971         return tcp_conn_request(&tcp6_request_sock_ops,
 972                                 &tcp_request_sock_ipv6_ops, sk, skb);
 973
 974 drop:
 975         NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
 976         return 0; /* don't send reset */
 977 }
 978
 979 static struct sock *tcp_v6_syn_recv_sock(const struct sock *sk, struct sk_buff *skb,
 980                                          struct request_sock *req,
 981                                          struct dst_entry *dst,
 982                                          struct request_sock *req_unhash,
 983                                          bool *own_req)
 984 {
 985         struct inet_request_sock *ireq;
 986         struct ipv6_pinfo *newnp;
 987         const struct ipv6_pinfo *np = inet6_sk(sk);
 988         struct ipv6_txoptions *opt;
 989         struct tcp6_sock *newtcp6sk;
 990         struct inet_sock *newinet;
 991         struct tcp_sock *newtp;
 992         struct sock *newsk;
 993 #ifdef CONFIG_TCP_MD5SIG
 994         struct tcp_md5sig_key *key;
 995 #endif
 996         struct flowi6 fl6;
 997
 998         if (skb->protocol == htons(ETH_P_IP)) {
 999                 /*
1000                  *      v6 mapped
1001                  */
1002
1003                 newsk = tcp_v4_syn_recv_sock(sk, skb, req, dst,
1004                                              req_unhash, own_req);
1005
1006                 if (!newsk)
1007                         return NULL;
1008
1009                 newtcp6sk = (struct tcp6_sock *)newsk;
1010                 inet_sk(newsk)->pinet6 = &newtcp6sk->inet6;
1011
1012                 newinet = inet_sk(newsk);
1013                 newnp = inet6_sk(newsk);
1014                 newtp = tcp_sk(newsk);
1015
1016                 memcpy(newnp, np, sizeof(struct ipv6_pinfo));
1017
1018                 newnp->saddr = newsk->sk_v6_rcv_saddr;
1019
1020                 inet_csk(newsk)->icsk_af_ops = &ipv6_mapped;
1021                 newsk->sk_backlog_rcv = tcp_v4_do_rcv;
1022 #ifdef CONFIG_TCP_MD5SIG
1023                 newtp->af_specific = &tcp_sock_ipv6_mapped_specific;
1024 #endif
1025
1026                 newnp->ipv6_ac_list = NULL;
1027                 newnp->ipv6_fl_list = NULL;
1028                 newnp->pktoptions  = NULL;
1029                 newnp->opt         = NULL;
1030                 newnp->mcast_oif   = tcp_v6_iif(skb);
1031                 newnp->mcast_hops  = ipv6_hdr(skb)->hop_limit;
1032                 newnp->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(skb));
1033                 if (np->repflow)
1034                         newnp->flow_label = ip6_flowlabel(ipv6_hdr(skb));
1035
1036                 /*
1037                  * No need to charge this sock to the relevant IPv6 refcnt debug socks count
1038                  * here, tcp_create_openreq_child now does this for us, see the comment in
1039                  * that function for the gory details. -acme
1040                  */
1041
1042                 /* It is tricky place. Until this moment IPv4 tcp
1043                    worked with IPv6 icsk.icsk_af_ops.
1044                    Sync it now.
1045                  */
1046                 tcp_sync_mss(newsk, inet_csk(newsk)->icsk_pmtu_cookie);
1047
1048                 return newsk;
1049         }
1050
1051         ireq = inet_rsk(req);
1052
1053         if (sk_acceptq_is_full(sk))
1054                 goto out_overflow;
1055
1056         if (!dst) {
1057                 dst = inet6_csk_route_req(sk, &fl6, req, IPPROTO_TCP);
1058                 if (!dst)
1059                         goto out;
1060         }
1061
1062         newsk = tcp_create_openreq_child(sk, req, skb);
1063         if (!newsk)
1064                 goto out_nonewsk;
1065
1066         /*
1067          * No need to charge this sock to the relevant IPv6 refcnt debug socks
1068          * count here, tcp_create_openreq_child now does this for us, see the
1069          * comment in that function for the gory details. -acme
1070          */
1071
1072         newsk->sk_gso_type = SKB_GSO_TCPV6;
1073         ip6_dst_store(newsk, dst, NULL, NULL);
1074         inet6_sk_rx_dst_set(newsk, skb);
1075
1076         newtcp6sk = (struct tcp6_sock *)newsk;
1077         inet_sk(newsk)->pinet6 = &newtcp6sk->inet6;
1078
1079         newtp = tcp_sk(newsk);
1080         newinet = inet_sk(newsk);
1081         newnp = inet6_sk(newsk);
1082
1083         memcpy(newnp, np, sizeof(struct ipv6_pinfo));
1084
1085         newsk->sk_v6_daddr = ireq->ir_v6_rmt_addr;
1086         newnp->saddr = ireq->ir_v6_loc_addr;
1087         newsk->sk_v6_rcv_saddr = ireq->ir_v6_loc_addr;
1088         newsk->sk_bound_dev_if = ireq->ir_iif;
1089
1090         /* Now IPv6 options...
1091
1092            First: no IPv4 options.
1093          */
1094         newinet->inet_opt = NULL;
1095         newnp->ipv6_ac_list = NULL;
1096         newnp->ipv6_fl_list = NULL;
1097
1098         /* Clone RX bits */
1099         newnp->rxopt.all = np->rxopt.all;
1100
1101         newnp->pktoptions = NULL;
1102         newnp->opt        = NULL;
1103         newnp->mcast_oif  = tcp_v6_iif(skb);
1104         newnp->mcast_hops = ipv6_hdr(skb)->hop_limit;
1105         newnp->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(skb));
1106         if (np->repflow)
1107                 newnp->flow_label = ip6_flowlabel(ipv6_hdr(skb));
1108
1109         /* Clone native IPv6 options from listening socket (if any)
1110
1111            Yes, keeping reference count would be much more clever,
1112            but we make one more one thing there: reattach optmem
1113            to newsk.
1114          */
1115         opt = rcu_dereference(np->opt);
1116         if (opt) {
1117                 opt = ipv6_dup_options(newsk, opt);
1118                 RCU_INIT_POINTER(newnp->opt, opt);
1119         }
1120         inet_csk(newsk)->icsk_ext_hdr_len = 0;
1121         if (opt)
1122                 inet_csk(newsk)->icsk_ext_hdr_len = opt->opt_nflen +
1123                                                     opt->opt_flen;
1124
1125         tcp_ca_openreq_child(newsk, dst);
1126
1127         tcp_sync_mss(newsk, dst_mtu(dst));
1128         newtp->advmss = dst_metric_advmss(dst);
1129         if (tcp_sk(sk)->rx_opt.user_mss &&
1130             tcp_sk(sk)->rx_opt.user_mss < newtp->advmss)
1131                 newtp->advmss = tcp_sk(sk)->rx_opt.user_mss;
1132
1133         tcp_initialize_rcv_mss(newsk);
1134
1135         newinet->inet_daddr = newinet->inet_saddr = LOOPBACK4_IPV6;
1136         newinet->inet_rcv_saddr = LOOPBACK4_IPV6;
1137
1138 #ifdef CONFIG_TCP_MD5SIG
1139         /* Copy over the MD5 key from the original socket */
1140         key = tcp_v6_md5_do_lookup(sk, &newsk->sk_v6_daddr);
1141         if (key) {
1142                 /* We're using one, so create a matching key
1143                  * on the newsk structure. If we fail to get
1144                  * memory, then we end up not copying the key
1145                  * across. Shucks.
1146                  */
1147                 tcp_md5_do_add(newsk, (union tcp_md5_addr *)&newsk->sk_v6_daddr,
1148                                AF_INET6, key->key, key->keylen,
1149                                sk_gfp_mask(sk, GFP_ATOMIC));
1150         }
1151 #endif
1152
1153         if (__inet_inherit_port(sk, newsk) < 0) {
1154                 inet_csk_prepare_forced_close(newsk);
1155                 tcp_done(newsk);
1156                 goto out;
1157         }
1158         *own_req = inet_ehash_nolisten(newsk, req_to_sk(req_unhash));
1159         if (*own_req) {
1160                 tcp_move_syn(newtp, req);
1161
1162                 /* Clone pktoptions received with SYN, if we own the req */
1163                 if (ireq->pktopts) {
1164                         newnp->pktoptions = skb_clone(ireq->pktopts,
1165                                                       sk_gfp_mask(sk, GFP_ATOMIC));
1166                         consume_skb(ireq->pktopts);
1167                         ireq->pktopts = NULL;
1168                         if (newnp->pktoptions)
1169                                 skb_set_owner_r(newnp->pktoptions, newsk);
1170                 }
1171         }
1172
1173         return newsk;
1174
1175 out_overflow:
1176         NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
1177 out_nonewsk:
1178         dst_release(dst);
1179 out:
1180         NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
1181         return NULL;
1182 }
1183
1184 /* The socket must have it's spinlock held when we get
1185  * here, unless it is a TCP_LISTEN socket.
1186  *
1187  * We have a potential double-lock case here, so even when
1188  * doing backlog processing we use the BH locking scheme.
1189  * This is because we cannot sleep with the original spinlock
1190  * held.
1191  */
1192 static int tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb)
1193 {
1194         struct ipv6_pinfo *np = inet6_sk(sk);
1195         struct tcp_sock *tp;
1196         struct sk_buff *opt_skb = NULL;
1197
1198         /* Imagine: socket is IPv6. IPv4 packet arrives,
1199            goes to IPv4 receive handler and backlogged.
1200            From backlog it always goes here. Kerboom...
1201            Fortunately, tcp_rcv_established and rcv_established
1202            handle them correctly, but it is not case with
1203            tcp_v6_hnd_req and tcp_v6_send_reset().   --ANK
1204          */
1205
1206         if (skb->protocol == htons(ETH_P_IP))
1207                 return tcp_v4_do_rcv(sk, skb);
1208
1209         if (sk_filter(sk, skb))
1210                 goto discard;
1211
1212         /*
1213          *      socket locking is here for SMP purposes as backlog rcv
1214          *      is currently called with bh processing disabled.
1215          */
1216
1217         /* Do Stevens' IPV6_PKTOPTIONS.
1218
1219            Yes, guys, it is the only place in our code, where we
1220            may make it not affecting IPv4.
1221            The rest of code is protocol independent,
1222            and I do not like idea to uglify IPv4.
1223
1224            Actually, all the idea behind IPV6_PKTOPTIONS
1225            looks not very well thought. For now we latch
1226            options, received in the last packet, enqueued
1227            by tcp. Feel free to propose better solution.
1228                                                --ANK (980728)
1229          */
1230         if (np->rxopt.all)
1231                 opt_skb = skb_clone(skb, sk_gfp_mask(sk, GFP_ATOMIC));
1232
1233         if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
1234                 struct dst_entry *dst = sk->sk_rx_dst;
1235
1236                 sock_rps_save_rxhash(sk, skb);
1237                 sk_mark_napi_id(sk, skb);
1238                 if (dst) {
1239                         if (inet_sk(sk)->rx_dst_ifindex != skb->skb_iif ||
1240                             dst->ops->check(dst, np->rx_dst_cookie) == NULL) {
1241                                 dst_release(dst);
1242                                 sk->sk_rx_dst = NULL;
1243                         }
1244                 }
1245
1246                 tcp_rcv_established(sk, skb, tcp_hdr(skb), skb->len);
1247                 if (opt_skb)
1248                         goto ipv6_pktoptions;
1249                 return 0;
1250         }
1251
1252         if (tcp_checksum_complete(skb))
1253                 goto csum_err;
1254
1255         if (sk->sk_state == TCP_LISTEN) {
1256                 struct sock *nsk = tcp_v6_cookie_check(sk, skb);
1257
1258                 if (!nsk)
1259                         goto discard;
1260
1261                 if (nsk != sk) {
1262                         sock_rps_save_rxhash(nsk, skb);
1263                         sk_mark_napi_id(nsk, skb);
1264                         if (tcp_child_process(sk, nsk, skb))
1265                                 goto reset;
1266                         if (opt_skb)
1267                                 __kfree_skb(opt_skb);
1268                         return 0;
1269                 }
1270         } else
1271                 sock_rps_save_rxhash(sk, skb);
1272
1273         if (tcp_rcv_state_process(sk, skb))
1274                 goto reset;
1275         if (opt_skb)
1276                 goto ipv6_pktoptions;
1277         return 0;
1278
1279 reset:
1280         tcp_v6_send_reset(sk, skb);
1281 discard:
1282         if (opt_skb)
1283                 __kfree_skb(opt_skb);
1284         kfree_skb(skb);
1285         return 0;
1286 csum_err:
1287         TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_CSUMERRORS);
1288         TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_INERRS);
1289         goto discard;
1290
1291
1292 ipv6_pktoptions:
1293         /* Do you ask, what is it?
1294
1295            1. skb was enqueued by tcp.
1296            2. skb is added to tail of read queue, rather than out of order.
1297            3. socket is not in passive state.
1298            4. Finally, it really contains options, which user wants to receive.
1299          */
1300         tp = tcp_sk(sk);
1301         if (TCP_SKB_CB(opt_skb)->end_seq == tp->rcv_nxt &&
1302             !((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN))) {
1303                 if (np->rxopt.bits.rxinfo || np->rxopt.bits.rxoinfo)
1304                         np->mcast_oif = tcp_v6_iif(opt_skb);
1305                 if (np->rxopt.bits.rxhlim || np->rxopt.bits.rxohlim)
1306                         np->mcast_hops = ipv6_hdr(opt_skb)->hop_limit;
1307                 if (np->rxopt.bits.rxflow || np->rxopt.bits.rxtclass)
1308                         np->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(opt_skb));
1309                 if (np->repflow)
1310                         np->flow_label = ip6_flowlabel(ipv6_hdr(opt_skb));
1311                 if (ipv6_opt_accepted(sk, opt_skb, &TCP_SKB_CB(opt_skb)->header.h6)) {
1312                         skb_set_owner_r(opt_skb, sk);
1313                         opt_skb = xchg(&np->pktoptions, opt_skb);
1314                 } else {
1315                         __kfree_skb(opt_skb);
1316                         opt_skb = xchg(&np->pktoptions, NULL);
1317                 }
1318         }
1319
1320         kfree_skb(opt_skb);
1321         return 0;
1322 }
1323
1324 static void tcp_v6_fill_cb(struct sk_buff *skb, const struct ipv6hdr *hdr,
1325                            const struct tcphdr *th)
1326 {
1327         /* This is tricky: we move IP6CB at its correct location into
1328          * TCP_SKB_CB(). It must be done after xfrm6_policy_check(), because
1329          * _decode_session6() uses IP6CB().
1330          * barrier() makes sure compiler won't play aliasing games.
1331          */
1332         memmove(&TCP_SKB_CB(skb)->header.h6, IP6CB(skb),
1333                 sizeof(struct inet6_skb_parm));
1334         barrier();
1335
1336         TCP_SKB_CB(skb)->seq = ntohl(th->seq);
1337         TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
1338                                     skb->len - th->doff*4);
1339         TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
1340         TCP_SKB_CB(skb)->tcp_flags = tcp_flag_byte(th);
1341         TCP_SKB_CB(skb)->tcp_tw_isn = 0;
1342         TCP_SKB_CB(skb)->ip_dsfield = ipv6_get_dsfield(hdr);
1343         TCP_SKB_CB(skb)->sacked = 0;
1344 }
1345
1346 static void tcp_v6_restore_cb(struct sk_buff *skb)
1347 {
1348         /* We need to move header back to the beginning if xfrm6_policy_check()
1349          * and tcp_v6_fill_cb() are going to be called again.
1350          */
1351         memmove(IP6CB(skb), &TCP_SKB_CB(skb)->header.h6,
1352                 sizeof(struct inet6_skb_parm));
1353 }
1354
1355 static int tcp_v6_rcv(struct sk_buff *skb)
1356 {
1357         const struct tcphdr *th;
1358         const struct ipv6hdr *hdr;
1359         struct sock *sk;
1360         int ret;
1361         struct net *net = dev_net(skb->dev);
1362
1363         if (skb->pkt_type != PACKET_HOST)
1364                 goto discard_it;
1365
1366         /*
1367          *      Count it even if it's bad.
1368          */
1369         TCP_INC_STATS_BH(net, TCP_MIB_INSEGS);
1370
1371         if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
1372                 goto discard_it;
1373
1374         th = tcp_hdr(skb);
1375
1376         if (th->doff < sizeof(struct tcphdr)/4)
1377                 goto bad_packet;
1378         if (!pskb_may_pull(skb, th->doff*4))
1379                 goto discard_it;
1380
1381         if (skb_checksum_init(skb, IPPROTO_TCP, ip6_compute_pseudo))
1382                 goto csum_error;
1383
1384         th = tcp_hdr(skb);
1385         hdr = ipv6_hdr(skb);
1386
1387 lookup:
1388         sk = __inet6_lookup_skb(&tcp_hashinfo, skb, __tcp_hdrlen(th),
1389                                 th->source, th->dest, inet6_iif(skb));
1390         if (!sk)
1391                 goto no_tcp_socket;
1392
1393 process:
1394         if (sk->sk_state == TCP_TIME_WAIT)
1395                 goto do_time_wait;
1396
1397         if (sk->sk_state == TCP_NEW_SYN_RECV) {
1398                 struct request_sock *req = inet_reqsk(sk);
1399                 struct sock *nsk;
1400
1401                 sk = req->rsk_listener;
1402                 tcp_v6_fill_cb(skb, hdr, th);
1403                 if (tcp_v6_inbound_md5_hash(sk, skb)) {
1404                         reqsk_put(req);
1405                         goto discard_it;
1406                 }
1407                 if (unlikely(sk->sk_state != TCP_LISTEN)) {
1408                         inet_csk_reqsk_queue_drop_and_put(sk, req);
1409                         goto lookup;
1410                 }
1411                 sock_hold(sk);
1412                 nsk = tcp_check_req(sk, skb, req, false);
1413                 if (!nsk) {
1414                         reqsk_put(req);
1415                         goto discard_and_relse;
1416                 }
1417                 if (nsk == sk) {
1418                         reqsk_put(req);
1419                         tcp_v6_restore_cb(skb);
1420                 } else if (tcp_child_process(sk, nsk, skb)) {
1421                         tcp_v6_send_reset(nsk, skb);
1422                         goto discard_and_relse;
1423                 } else {
1424                         sock_put(sk);
1425                         return 0;
1426                 }
1427         }
1428         if (hdr->hop_limit < inet6_sk(sk)->min_hopcount) {
1429                 NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP);
1430                 goto discard_and_relse;
1431         }
1432
1433         if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb))
1434                 goto discard_and_relse;
1435
1436         tcp_v6_fill_cb(skb, hdr, th);
1437
1438         if (tcp_v6_inbound_md5_hash(sk, skb))
1439                 goto discard_and_relse;
1440
1441         if (sk_filter(sk, skb))
1442                 goto discard_and_relse;
1443
1444         skb->dev = NULL;
1445
1446         if (sk->sk_state == TCP_LISTEN) {
1447                 ret = tcp_v6_do_rcv(sk, skb);
1448                 goto put_and_return;
1449         }
1450
1451         sk_incoming_cpu_update(sk);
1452
1453         bh_lock_sock_nested(sk);
1454         tcp_segs_in(tcp_sk(sk), skb);
1455         ret = 0;
1456         if (!sock_owned_by_user(sk)) {
1457                 if (!tcp_prequeue(sk, skb))
1458                         ret = tcp_v6_do_rcv(sk, skb);
1459         } else if (unlikely(sk_add_backlog(sk, skb,
1460                                            sk->sk_rcvbuf + sk->sk_sndbuf))) {
1461                 bh_unlock_sock(sk);
1462                 NET_INC_STATS_BH(net, LINUX_MIB_TCPBACKLOGDROP);
1463                 goto discard_and_relse;
1464         }
1465         bh_unlock_sock(sk);
1466
1467 put_and_return:
1468         sock_put(sk);
1469         return ret ? -1 : 0;
1470
1471 no_tcp_socket:
1472         if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb))
1473                 goto discard_it;
1474
1475         tcp_v6_fill_cb(skb, hdr, th);
1476
1477         if (tcp_checksum_complete(skb)) {
1478 csum_error:
1479                 TCP_INC_STATS_BH(net, TCP_MIB_CSUMERRORS);
1480 bad_packet:
1481                 TCP_INC_STATS_BH(net, TCP_MIB_INERRS);
1482         } else {
1483                 tcp_v6_send_reset(NULL, skb);
1484         }
1485
1486 discard_it:
1487         kfree_skb(skb);
1488         return 0;
1489
1490 discard_and_relse:
1491         sock_put(sk);
1492         goto discard_it;
1493
1494 do_time_wait:
1495         if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
1496                 inet_twsk_put(inet_twsk(sk));
1497                 goto discard_it;
1498         }
1499
1500         tcp_v6_fill_cb(skb, hdr, th);
1501
1502         if (tcp_checksum_complete(skb)) {
1503                 inet_twsk_put(inet_twsk(sk));
1504                 goto csum_error;
1505         }
1506
1507         switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) {
1508         case TCP_TW_SYN:
1509         {
1510                 struct sock *sk2;
1511
1512                 sk2 = inet6_lookup_listener(dev_net(skb->dev), &tcp_hashinfo,
1513                                             skb, __tcp_hdrlen(th),
1514                                             &ipv6_hdr(skb)->saddr, th->source,
1515                                             &ipv6_hdr(skb)->daddr,
1516                                             ntohs(th->dest), tcp_v6_iif(skb));
1517                 if (sk2) {
1518                         struct inet_timewait_sock *tw = inet_twsk(sk);
1519                         inet_twsk_deschedule_put(tw);
1520                         sk = sk2;
1521                         tcp_v6_restore_cb(skb);
1522                         goto process;
1523                 }
1524                 /* Fall through to ACK */
1525         }
1526         case TCP_TW_ACK:
1527                 tcp_v6_timewait_ack(sk, skb);
1528                 break;
1529         case TCP_TW_RST:
1530                 tcp_v6_restore_cb(skb);
1531                 tcp_v6_send_reset(sk, skb);
1532                 inet_twsk_deschedule_put(inet_twsk(sk));
1533                 goto discard_it;
1534         case TCP_TW_SUCCESS:
1535                 ;
1536         }
1537         goto discard_it;
1538 }
1539
1540 static void tcp_v6_early_demux(struct sk_buff *skb)
1541 {
1542         const struct ipv6hdr *hdr;
1543         const struct tcphdr *th;
1544         struct sock *sk;
1545
1546         if (skb->pkt_type != PACKET_HOST)
1547                 return;
1548
1549         if (!pskb_may_pull(skb, skb_transport_offset(skb) + sizeof(struct tcphdr)))
1550                 return;
1551
1552         hdr = ipv6_hdr(skb);
1553         th = tcp_hdr(skb);
1554
1555         if (th->doff < sizeof(struct tcphdr) / 4)
1556                 return;
1557
1558         /* Note : We use inet6_iif() here, not tcp_v6_iif() */
1559         sk = __inet6_lookup_established(dev_net(skb->dev), &tcp_hashinfo,
1560                                         &hdr->saddr, th->source,
1561                                         &hdr->daddr, ntohs(th->dest),
1562                                         inet6_iif(skb));
1563         if (sk) {
1564                 skb->sk = sk;
1565                 skb->destructor = sock_edemux;
1566                 if (sk_fullsock(sk)) {
1567                         struct dst_entry *dst = READ_ONCE(sk->sk_rx_dst);
1568
1569                         if (dst)
1570                                 dst = dst_check(dst, inet6_sk(sk)->rx_dst_cookie);
1571                         if (dst &&
1572                             inet_sk(sk)->rx_dst_ifindex == skb->skb_iif)
1573                                 skb_dst_set_noref(skb, dst);
1574                 }
1575         }
1576 }
1577
1578 static struct timewait_sock_ops tcp6_timewait_sock_ops = {
1579         .twsk_obj_size  = sizeof(struct tcp6_timewait_sock),
1580         .twsk_unique    = tcp_twsk_unique,
1581         .twsk_destructor = tcp_twsk_destructor,
1582 };
1583
1584 static const struct inet_connection_sock_af_ops ipv6_specific = {
1585         .queue_xmit        = inet6_csk_xmit,
1586         .send_check        = tcp_v6_send_check,
1587         .rebuild_header    = inet6_sk_rebuild_header,
1588         .sk_rx_dst_set     = inet6_sk_rx_dst_set,
1589         .conn_request      = tcp_v6_conn_request,
1590         .syn_recv_sock     = tcp_v6_syn_recv_sock,
1591         .net_header_len    = sizeof(struct ipv6hdr),
1592         .net_frag_header_len = sizeof(struct frag_hdr),
1593         .setsockopt        = ipv6_setsockopt,
1594         .getsockopt        = ipv6_getsockopt,
1595         .addr2sockaddr     = inet6_csk_addr2sockaddr,
1596         .sockaddr_len      = sizeof(struct sockaddr_in6),
1597         .bind_conflict     = inet6_csk_bind_conflict,
1598 #ifdef CONFIG_COMPAT
1599         .compat_setsockopt = compat_ipv6_setsockopt,
1600         .compat_getsockopt = compat_ipv6_getsockopt,
1601 #endif
1602         .mtu_reduced       = tcp_v6_mtu_reduced,
1603 };
1604
1605 #ifdef CONFIG_TCP_MD5SIG
1606 static const struct tcp_sock_af_ops tcp_sock_ipv6_specific = {
1607         .md5_lookup     =       tcp_v6_md5_lookup,
1608         .calc_md5_hash  =       tcp_v6_md5_hash_skb,
1609         .md5_parse      =       tcp_v6_parse_md5_keys,
1610 };
1611 #endif
1612
1613 /*
1614  *      TCP over IPv4 via INET6 API
1615  */
1616 static const struct inet_connection_sock_af_ops ipv6_mapped = {
1617         .queue_xmit        = ip_queue_xmit,
1618         .send_check        = tcp_v4_send_check,
1619         .rebuild_header    = inet_sk_rebuild_header,
1620         .sk_rx_dst_set     = inet_sk_rx_dst_set,
1621         .conn_request      = tcp_v6_conn_request,
1622         .syn_recv_sock     = tcp_v6_syn_recv_sock,
1623         .net_header_len    = sizeof(struct iphdr),
1624         .setsockopt        = ipv6_setsockopt,
1625         .getsockopt        = ipv6_getsockopt,
1626         .addr2sockaddr     = inet6_csk_addr2sockaddr,
1627         .sockaddr_len      = sizeof(struct sockaddr_in6),
1628         .bind_conflict     = inet6_csk_bind_conflict,
1629 #ifdef CONFIG_COMPAT
1630         .compat_setsockopt = compat_ipv6_setsockopt,
1631         .compat_getsockopt = compat_ipv6_getsockopt,
1632 #endif
1633         .mtu_reduced       = tcp_v4_mtu_reduced,
1634 };
1635
1636 #ifdef CONFIG_TCP_MD5SIG
1637 static const struct tcp_sock_af_ops tcp_sock_ipv6_mapped_specific = {
1638         .md5_lookup     =       tcp_v4_md5_lookup,
1639         .calc_md5_hash  =       tcp_v4_md5_hash_skb,
1640         .md5_parse      =       tcp_v6_parse_md5_keys,
1641 };
1642 #endif
1643
1644 /* NOTE: A lot of things set to zero explicitly by call to
1645  *       sk_alloc() so need not be done here.
1646  */
1647 static int tcp_v6_init_sock(struct sock *sk)
1648 {
1649         struct inet_connection_sock *icsk = inet_csk(sk);
1650
1651         tcp_init_sock(sk);
1652
1653         icsk->icsk_af_ops = &ipv6_specific;
1654
1655 #ifdef CONFIG_TCP_MD5SIG
1656         tcp_sk(sk)->af_specific = &tcp_sock_ipv6_specific;
1657 #endif
1658
1659         return 0;
1660 }
1661
1662 static void tcp_v6_destroy_sock(struct sock *sk)
1663 {
1664         tcp_v4_destroy_sock(sk);
1665         inet6_destroy_sock(sk);
1666 }
1667
1668 #ifdef CONFIG_PROC_FS
1669 /* Proc filesystem TCPv6 sock list dumping. */
1670 static void get_openreq6(struct seq_file *seq,
1671                          const struct request_sock *req, int i)
1672 {
1673         long ttd = req->rsk_timer.expires - jiffies;
1674         const struct in6_addr *src = &inet_rsk(req)->ir_v6_loc_addr;
1675         const struct in6_addr *dest = &inet_rsk(req)->ir_v6_rmt_addr;
1676
1677         if (ttd < 0)
1678                 ttd = 0;
1679
1680         seq_printf(seq,
1681                    "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
1682                    "%02X %08X:%08X %02X:%08lX %08X %5u %8d %d %d %pK\n",
1683                    i,
1684                    src->s6_addr32[0], src->s6_addr32[1],
1685                    src->s6_addr32[2], src->s6_addr32[3],
1686                    inet_rsk(req)->ir_num,
1687                    dest->s6_addr32[0], dest->s6_addr32[1],
1688                    dest->s6_addr32[2], dest->s6_addr32[3],
1689                    ntohs(inet_rsk(req)->ir_rmt_port),
1690                    TCP_SYN_RECV,
1691                    0, 0, /* could print option size, but that is af dependent. */
1692                    1,   /* timers active (only the expire timer) */
1693                    jiffies_to_clock_t(ttd),
1694                    req->num_timeout,
1695                    from_kuid_munged(seq_user_ns(seq),
1696                                     sock_i_uid(req->rsk_listener)),
1697                    0,  /* non standard timer */
1698                    0, /* open_requests have no inode */
1699                    0, req);
1700 }
1701
1702 static void get_tcp6_sock(struct seq_file *seq, struct sock *sp, int i)
1703 {
1704         const struct in6_addr *dest, *src;
1705         __u16 destp, srcp;
1706         int timer_active;
1707         unsigned long timer_expires;
1708         const struct inet_sock *inet = inet_sk(sp);
1709         const struct tcp_sock *tp = tcp_sk(sp);
1710         const struct inet_connection_sock *icsk = inet_csk(sp);
1711         const struct fastopen_queue *fastopenq = &icsk->icsk_accept_queue.fastopenq;
1712         int rx_queue;
1713         int state;
1714
1715         dest  = &sp->sk_v6_daddr;
1716         src   = &sp->sk_v6_rcv_saddr;
1717         destp = ntohs(inet->inet_dport);
1718         srcp  = ntohs(inet->inet_sport);
1719
1720         if (icsk->icsk_pending == ICSK_TIME_RETRANS) {
1721                 timer_active    = 1;
1722                 timer_expires   = icsk->icsk_timeout;
1723         } else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
1724                 timer_active    = 4;
1725                 timer_expires   = icsk->icsk_timeout;
1726         } else if (timer_pending(&sp->sk_timer)) {
1727                 timer_active    = 2;
1728                 timer_expires   = sp->sk_timer.expires;
1729         } else {
1730                 timer_active    = 0;
1731                 timer_expires = jiffies;
1732         }
1733
1734         state = sk_state_load(sp);
1735         if (state == TCP_LISTEN)
1736                 rx_queue = sp->sk_ack_backlog;
1737         else
1738                 /* Because we don't lock the socket,
1739                  * we might find a transient negative value.
1740                  */
1741                 rx_queue = max_t(int, tp->rcv_nxt - tp->copied_seq, 0);
1742
1743         seq_printf(seq,
1744                    "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
1745                    "%02X %08X:%08X %02X:%08lX %08X %5u %8d %lu %d %pK %lu %lu %u %u %d\n",
1746                    i,
1747                    src->s6_addr32[0], src->s6_addr32[1],
1748                    src->s6_addr32[2], src->s6_addr32[3], srcp,
1749                    dest->s6_addr32[0], dest->s6_addr32[1],
1750                    dest->s6_addr32[2], dest->s6_addr32[3], destp,
1751                    state,
1752                    tp->write_seq - tp->snd_una,
1753                    rx_queue,
1754                    timer_active,
1755                    jiffies_delta_to_clock_t(timer_expires - jiffies),
1756                    icsk->icsk_retransmits,
1757                    from_kuid_munged(seq_user_ns(seq), sock_i_uid(sp)),
1758                    icsk->icsk_probes_out,
1759                    sock_i_ino(sp),
1760                    atomic_read(&sp->sk_refcnt), sp,
1761                    jiffies_to_clock_t(icsk->icsk_rto),
1762                    jiffies_to_clock_t(icsk->icsk_ack.ato),
1763                    (icsk->icsk_ack.quick << 1) | icsk->icsk_ack.pingpong,
1764                    tp->snd_cwnd,
1765                    state == TCP_LISTEN ?
1766                         fastopenq->max_qlen :
1767                         (tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh)
1768                    );
1769 }
1770
1771 static void get_timewait6_sock(struct seq_file *seq,
1772                                struct inet_timewait_sock *tw, int i)
1773 {
1774         long delta = tw->tw_timer.expires - jiffies;
1775         const struct in6_addr *dest, *src;
1776         __u16 destp, srcp;
1777
1778         dest = &tw->tw_v6_daddr;
1779         src  = &tw->tw_v6_rcv_saddr;
1780         destp = ntohs(tw->tw_dport);
1781         srcp  = ntohs(tw->tw_sport);
1782
1783         seq_printf(seq,
1784                    "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
1785                    "%02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK\n",
1786                    i,
1787                    src->s6_addr32[0], src->s6_addr32[1],
1788                    src->s6_addr32[2], src->s6_addr32[3], srcp,
1789                    dest->s6_addr32[0], dest->s6_addr32[1],
1790                    dest->s6_addr32[2], dest->s6_addr32[3], destp,
1791                    tw->tw_substate, 0, 0,
1792                    3, jiffies_delta_to_clock_t(delta), 0, 0, 0, 0,
1793                    atomic_read(&tw->tw_refcnt), tw);
1794 }
1795
1796 static int tcp6_seq_show(struct seq_file *seq, void *v)
1797 {
1798         struct tcp_iter_state *st;
1799         struct sock *sk = v;
1800
1801         if (v == SEQ_START_TOKEN) {
1802                 seq_puts(seq,
1803                          "  sl  "
1804                          "local_address                         "
1805                          "remote_address                        "
1806                          "st tx_queue rx_queue tr tm->when retrnsmt"
1807                          "   uid  timeout inode\n");
1808                 goto out;
1809         }
1810         st = seq->private;
1811
1812         if (sk->sk_state == TCP_TIME_WAIT)
1813                 get_timewait6_sock(seq, v, st->num);
1814         else if (sk->sk_state == TCP_NEW_SYN_RECV)
1815                 get_openreq6(seq, v, st->num);
1816         else
1817                 get_tcp6_sock(seq, v, st->num);
1818 out:
1819         return 0;
1820 }
1821
1822 static const struct file_operations tcp6_afinfo_seq_fops = {
1823         .owner   = THIS_MODULE,
1824         .open    = tcp_seq_open,
1825         .read    = seq_read,
1826         .llseek  = seq_lseek,
1827         .release = seq_release_net
1828 };
1829
1830 static struct tcp_seq_afinfo tcp6_seq_afinfo = {
1831         .name           = "tcp6",
1832         .family         = AF_INET6,
1833         .seq_fops       = &tcp6_afinfo_seq_fops,
1834         .seq_ops        = {
1835                 .show           = tcp6_seq_show,
1836         },
1837 };
1838
1839 int __net_init tcp6_proc_init(struct net *net)
1840 {
1841         return tcp_proc_register(net, &tcp6_seq_afinfo);
1842 }
1843
1844 void tcp6_proc_exit(struct net *net)
1845 {
1846         tcp_proc_unregister(net, &tcp6_seq_afinfo);
1847 }
1848 #endif
1849
1850 static void tcp_v6_clear_sk(struct sock *sk, int size)
1851 {
1852         struct inet_sock *inet = inet_sk(sk);
1853
1854         /* we do not want to clear pinet6 field, because of RCU lookups */
1855         sk_prot_clear_nulls(sk, offsetof(struct inet_sock, pinet6));
1856
1857         size -= offsetof(struct inet_sock, pinet6) + sizeof(inet->pinet6);
1858         memset(&inet->pinet6 + 1, 0, size);
1859 }
1860
1861 struct proto tcpv6_prot = {
1862         .name                   = "TCPv6",
1863         .owner                  = THIS_MODULE,
1864         .close                  = tcp_close,
1865         .connect                = tcp_v6_connect,
1866         .disconnect             = tcp_disconnect,
1867         .accept                 = inet_csk_accept,
1868         .ioctl                  = tcp_ioctl,
1869         .init                   = tcp_v6_init_sock,
1870         .destroy                = tcp_v6_destroy_sock,
1871         .shutdown               = tcp_shutdown,
1872         .setsockopt             = tcp_setsockopt,
1873         .getsockopt             = tcp_getsockopt,
1874         .recvmsg                = tcp_recvmsg,
1875         .sendmsg                = tcp_sendmsg,
1876         .sendpage               = tcp_sendpage,
1877         .backlog_rcv            = tcp_v6_do_rcv,
1878         .release_cb             = tcp_release_cb,
1879         .hash                   = inet6_hash,
1880         .unhash                 = inet_unhash,
1881         .get_port               = inet_csk_get_port,
1882         .enter_memory_pressure  = tcp_enter_memory_pressure,
1883         .stream_memory_free     = tcp_stream_memory_free,
1884         .sockets_allocated      = &tcp_sockets_allocated,
1885         .memory_allocated       = &tcp_memory_allocated,
1886         .memory_pressure        = &tcp_memory_pressure,
1887         .orphan_count           = &tcp_orphan_count,
1888         .sysctl_mem             = sysctl_tcp_mem,
1889         .sysctl_wmem            = sysctl_tcp_wmem,
1890         .sysctl_rmem            = sysctl_tcp_rmem,
1891         .max_header             = MAX_TCP_HEADER,
1892         .obj_size               = sizeof(struct tcp6_sock),
1893         .slab_flags             = SLAB_DESTROY_BY_RCU,
1894         .twsk_prot              = &tcp6_timewait_sock_ops,
1895         .rsk_prot               = &tcp6_request_sock_ops,
1896         .h.hashinfo             = &tcp_hashinfo,
1897         .no_autobind            = true,
1898 #ifdef CONFIG_COMPAT
1899         .compat_setsockopt      = compat_tcp_setsockopt,
1900         .compat_getsockopt      = compat_tcp_getsockopt,
1901 #endif
1902         .clear_sk               = tcp_v6_clear_sk,
1903         .diag_destroy           = tcp_abort,
1904 };
1905
1906 static const struct inet6_protocol tcpv6_protocol = {
1907         .early_demux    =       tcp_v6_early_demux,
1908         .handler        =       tcp_v6_rcv,
1909         .err_handler    =       tcp_v6_err,
1910         .flags          =       INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
1911 };
1912
1913 static struct inet_protosw tcpv6_protosw = {
1914         .type           =       SOCK_STREAM,
1915         .protocol       =       IPPROTO_TCP,
1916         .prot           =       &tcpv6_prot,
1917         .ops            =       &inet6_stream_ops,
1918         .flags          =       INET_PROTOSW_PERMANENT |
1919                                 INET_PROTOSW_ICSK,
1920 };
1921
1922 static int __net_init tcpv6_net_init(struct net *net)
1923 {
1924         return inet_ctl_sock_create(&net->ipv6.tcp_sk, PF_INET6,
1925                                     SOCK_RAW, IPPROTO_TCP, net);
1926 }
1927
1928 static void __net_exit tcpv6_net_exit(struct net *net)
1929 {
1930         inet_ctl_sock_destroy(net->ipv6.tcp_sk);
1931 }
1932
1933 static void __net_exit tcpv6_net_exit_batch(struct list_head *net_exit_list)
1934 {
1935         inet_twsk_purge(&tcp_hashinfo, &tcp_death_row, AF_INET6);
1936 }
1937
1938 static struct pernet_operations tcpv6_net_ops = {
1939         .init       = tcpv6_net_init,
1940         .exit       = tcpv6_net_exit,
1941         .exit_batch = tcpv6_net_exit_batch,
1942 };
1943
1944 int __init tcpv6_init(void)
1945 {
1946         int ret;
1947
1948         ret = inet6_add_protocol(&tcpv6_protocol, IPPROTO_TCP);
1949         if (ret)
1950                 goto out;
1951
1952         /* register inet6 protocol */
1953         ret = inet6_register_protosw(&tcpv6_protosw);
1954         if (ret)
1955                 goto out_tcpv6_protocol;
1956
1957         ret = register_pernet_subsys(&tcpv6_net_ops);
1958         if (ret)
1959                 goto out_tcpv6_protosw;
1960 out:
1961         return ret;
1962
1963 out_tcpv6_protosw:
1964         inet6_unregister_protosw(&tcpv6_protosw);
1965 out_tcpv6_protocol:
1966         inet6_del_protocol(&tcpv6_protocol, IPPROTO_TCP);
1967         goto out;
1968 }
1969
1970 void tcpv6_exit(void)
1971 {
1972         unregister_pernet_subsys(&tcpv6_net_ops);
1973         inet6_unregister_protosw(&tcpv6_protosw);
1974         inet6_del_protocol(&tcpv6_protocol, IPPROTO_TCP);
1975 }