net/ipv6/tcp_ipv6.c

   1 /*
   2  *      TCP over IPv6
   3  *      Linux INET6 implementation
   4  *
   5  *      Authors:
   6  *      Pedro Roque             <roque@di.fc.ul.pt>
   7  *
   8  *      Based on:
   9  *      linux/net/ipv4/tcp.c
  10  *      linux/net/ipv4/tcp_input.c
  11  *      linux/net/ipv4/tcp_output.c
  12  *
  13  *      Fixes:
  14  *      Hideaki YOSHIFUJI       :       sin6_scope_id support
  15  *      YOSHIFUJI Hideaki @USAGI and:   Support IPV6_V6ONLY socket option, which
  16  *      Alexey Kuznetsov                allow both IPv4 and IPv6 sockets to bind
  17  *                                      a single port at the same time.
  18  *      YOSHIFUJI Hideaki @USAGI:       convert /proc/net/tcp6 to seq_file.
  19  *
  20  *      This program is free software; you can redistribute it and/or
  21  *      modify it under the terms of the GNU General Public License
  22  *      as published by the Free Software Foundation; either version
  23  *      2 of the License, or (at your option) any later version.
  24  */
  25
  26 #include <linux/bottom_half.h>
  27 #include <linux/module.h>
  28 #include <linux/errno.h>
  29 #include <linux/types.h>
  30 #include <linux/socket.h>
  31 #include <linux/sockios.h>
  32 #include <linux/net.h>
  33 #include <linux/jiffies.h>
  34 #include <linux/in.h>
  35 #include <linux/in6.h>
  36 #include <linux/netdevice.h>
  37 #include <linux/init.h>
  38 #include <linux/jhash.h>
  39 #include <linux/ipsec.h>
  40 #include <linux/times.h>
  41 #include <linux/slab.h>
  42 #include <linux/uaccess.h>
  43 #include <linux/ipv6.h>
  44 #include <linux/icmpv6.h>
  45 #include <linux/random.h>
  46
  47 #include <net/tcp.h>
  48 #include <net/ndisc.h>
  49 #include <net/inet6_hashtables.h>
  50 #include <net/inet6_connection_sock.h>
  51 #include <net/ipv6.h>
  52 #include <net/transp_v6.h>
  53 #include <net/addrconf.h>
  54 #include <net/ip6_route.h>
  55 #include <net/ip6_checksum.h>
  56 #include <net/inet_ecn.h>
  57 #include <net/protocol.h>
  58 #include <net/xfrm.h>
  59 #include <net/snmp.h>
  60 #include <net/dsfield.h>
  61 #include <net/timewait_sock.h>
  62 #include <net/inet_common.h>
  63 #include <net/secure_seq.h>
  64 #include <net/busy_poll.h>
  65
  66 #include <linux/proc_fs.h>
  67 #include <linux/seq_file.h>
  68
  69 #include <crypto/hash.h>
  70 #include <linux/scatterlist.h>
  71
  72 static void     tcp_v6_send_reset(const struct sock *sk, struct sk_buff *skb);
  73 static void     tcp_v6_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb,
  74                                       struct request_sock *req);
  75
  76 static int      tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb);
  77
  78 static const struct inet_connection_sock_af_ops ipv6_mapped;
  79 static const struct inet_connection_sock_af_ops ipv6_specific;
  80 #ifdef CONFIG_TCP_MD5SIG
  81 static const struct tcp_sock_af_ops tcp_sock_ipv6_specific;
  82 static const struct tcp_sock_af_ops tcp_sock_ipv6_mapped_specific;
  83 #else
  84 static struct tcp_md5sig_key *tcp_v6_md5_do_lookup(const struct sock *sk,
  85                                                    const struct in6_addr *addr)
  86 {
  87         return NULL;
  88 }
  89 #endif
  90
  91 static void inet6_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb)
  92 {
  93         struct dst_entry *dst = skb_dst(skb);
  94
  95         if (dst && dst_hold_safe(dst)) {
  96                 const struct rt6_info *rt = (const struct rt6_info *)dst;
  97
  98                 sk->sk_rx_dst = dst;
  99                 inet_sk(sk)->rx_dst_ifindex = skb->skb_iif;
 100                 inet6_sk(sk)->rx_dst_cookie = rt6_get_cookie(rt);
 101         }
 102 }
 103
 104 static __u32 tcp_v6_init_sequence(const struct sk_buff *skb)
 105 {
 106         return secure_tcpv6_sequence_number(ipv6_hdr(skb)->daddr.s6_addr32,
 107                                             ipv6_hdr(skb)->saddr.s6_addr32,
 108                                             tcp_hdr(skb)->dest,
 109                                             tcp_hdr(skb)->source);
 110 }
 111
 112 static int tcp_v6_connect(struct sock *sk, struct sockaddr *uaddr,
 113                           int addr_len)
 114 {
 115         struct sockaddr_in6 *usin = (struct sockaddr_in6 *) uaddr;
 116         struct inet_sock *inet = inet_sk(sk);
 117         struct inet_connection_sock *icsk = inet_csk(sk);
 118         struct ipv6_pinfo *np = inet6_sk(sk);
 119         struct tcp_sock *tp = tcp_sk(sk);
 120         struct in6_addr *saddr = NULL, *final_p, final;
 121         struct ipv6_txoptions *opt;
 122         struct flowi6 fl6;
 123         struct dst_entry *dst;
 124         int addr_type;
 125         int err;
 126
 127         if (addr_len < SIN6_LEN_RFC2133)
 128                 return -EINVAL;
 129
 130         if (usin->sin6_family != AF_INET6)
 131                 return -EAFNOSUPPORT;
 132
 133         memset(&fl6, 0, sizeof(fl6));
 134
 135         if (np->sndflow) {
 136                 fl6.flowlabel = usin->sin6_flowinfo&IPV6_FLOWINFO_MASK;
 137                 IP6_ECN_flow_init(fl6.flowlabel);
 138                 if (fl6.flowlabel&IPV6_FLOWLABEL_MASK) {
 139                         struct ip6_flowlabel *flowlabel;
 140                         flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
 141                         if (!flowlabel)
 142                                 return -EINVAL;
 143                         fl6_sock_release(flowlabel);
 144                 }
 145         }
 146
 147         /*
 148          *      connect() to INADDR_ANY means loopback (BSD'ism).
 149          */
 150
 151         if (ipv6_addr_any(&usin->sin6_addr))
 152                 usin->sin6_addr.s6_addr[15] = 0x1;
 153
 154         addr_type = ipv6_addr_type(&usin->sin6_addr);
 155
 156         if (addr_type & IPV6_ADDR_MULTICAST)
 157                 return -ENETUNREACH;
 158
 159         if (addr_type&IPV6_ADDR_LINKLOCAL) {
 160                 if (addr_len >= sizeof(struct sockaddr_in6) &&
 161                     usin->sin6_scope_id) {
 162                         /* If interface is set while binding, indices
 163                          * must coincide.
 164                          */
 165                         if (sk->sk_bound_dev_if &&
 166                             sk->sk_bound_dev_if != usin->sin6_scope_id)
 167                                 return -EINVAL;
 168
 169                         sk->sk_bound_dev_if = usin->sin6_scope_id;
 170                 }
 171
 172                 /* Connect to link-local address requires an interface */
 173                 if (!sk->sk_bound_dev_if)
 174                         return -EINVAL;
 175         }
 176
 177         if (tp->rx_opt.ts_recent_stamp &&
 178             !ipv6_addr_equal(&sk->sk_v6_daddr, &usin->sin6_addr)) {
 179                 tp->rx_opt.ts_recent = 0;
 180                 tp->rx_opt.ts_recent_stamp = 0;
 181                 tp->write_seq = 0;
 182         }
 183
 184         sk->sk_v6_daddr = usin->sin6_addr;
 185         np->flow_label = fl6.flowlabel;
 186
 187         /*
 188          *      TCP over IPv4
 189          */
 190
 191         if (addr_type == IPV6_ADDR_MAPPED) {
 192                 u32 exthdrlen = icsk->icsk_ext_hdr_len;
 193                 struct sockaddr_in sin;
 194
 195                 SOCK_DEBUG(sk, "connect: ipv4 mapped\n");
 196
 197                 if (__ipv6_only_sock(sk))
 198                         return -ENETUNREACH;
 199
 200                 sin.sin_family = AF_INET;
 201                 sin.sin_port = usin->sin6_port;
 202                 sin.sin_addr.s_addr = usin->sin6_addr.s6_addr32[3];
 203
 204                 icsk->icsk_af_ops = &ipv6_mapped;
 205                 sk->sk_backlog_rcv = tcp_v4_do_rcv;
 206 #ifdef CONFIG_TCP_MD5SIG
 207                 tp->af_specific = &tcp_sock_ipv6_mapped_specific;
 208 #endif
 209
 210                 err = tcp_v4_connect(sk, (struct sockaddr *)&sin, sizeof(sin));
 211
 212                 if (err) {
 213                         icsk->icsk_ext_hdr_len = exthdrlen;
 214                         icsk->icsk_af_ops = &ipv6_specific;
 215                         sk->sk_backlog_rcv = tcp_v6_do_rcv;
 216 #ifdef CONFIG_TCP_MD5SIG
 217                         tp->af_specific = &tcp_sock_ipv6_specific;
 218 #endif
 219                         goto failure;
 220                 }
 221                 np->saddr = sk->sk_v6_rcv_saddr;
 222
 223                 return err;
 224         }
 225
 226         if (!ipv6_addr_any(&sk->sk_v6_rcv_saddr))
 227                 saddr = &sk->sk_v6_rcv_saddr;
 228
 229         fl6.flowi6_proto = IPPROTO_TCP;
 230         fl6.daddr = sk->sk_v6_daddr;
 231         fl6.saddr = saddr ? *saddr : np->saddr;
 232         fl6.flowi6_oif = sk->sk_bound_dev_if;
 233         fl6.flowi6_mark = sk->sk_mark;
 234         fl6.fl6_dport = usin->sin6_port;
 235         fl6.fl6_sport = inet->inet_sport;
 236
 237         opt = rcu_dereference_protected(np->opt, lockdep_sock_is_held(sk));
 238         final_p = fl6_update_dst(&fl6, opt, &final);
 239
 240         security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));
 241
 242         dst = ip6_dst_lookup_flow(sk, &fl6, final_p);
 243         if (IS_ERR(dst)) {
 244                 err = PTR_ERR(dst);
 245                 goto failure;
 246         }
 247
 248         if (!saddr) {
 249                 saddr = &fl6.saddr;
 250                 sk->sk_v6_rcv_saddr = *saddr;
 251         }
 252
 253         /* set the source address */
 254         np->saddr = *saddr;
 255         inet->inet_rcv_saddr = LOOPBACK4_IPV6;
 256
 257         sk->sk_gso_type = SKB_GSO_TCPV6;
 258         ip6_dst_store(sk, dst, NULL, NULL);
 259
 260         if (tcp_death_row.sysctl_tw_recycle &&
 261             !tp->rx_opt.ts_recent_stamp &&
 262             ipv6_addr_equal(&fl6.daddr, &sk->sk_v6_daddr))
 263                 tcp_fetch_timewait_stamp(sk, dst);
 264
 265         icsk->icsk_ext_hdr_len = 0;
 266         if (opt)
 267                 icsk->icsk_ext_hdr_len = opt->opt_flen +
 268                                          opt->opt_nflen;
 269
 270         tp->rx_opt.mss_clamp = IPV6_MIN_MTU - sizeof(struct tcphdr) - sizeof(struct ipv6hdr);
 271
 272         inet->inet_dport = usin->sin6_port;
 273
 274         tcp_set_state(sk, TCP_SYN_SENT);
 275         err = inet6_hash_connect(&tcp_death_row, sk);
 276         if (err)
 277                 goto late_failure;
 278
 279         sk_set_txhash(sk);
 280
 281         if (!tp->write_seq && likely(!tp->repair))
 282                 tp->write_seq = secure_tcpv6_sequence_number(np->saddr.s6_addr32,
 283                                                              sk->sk_v6_daddr.s6_addr32,
 284                                                              inet->inet_sport,
 285                                                              inet->inet_dport);
 286
 287         err = tcp_connect(sk);
 288         if (err)
 289                 goto late_failure;
 290
 291         return 0;
 292
 293 late_failure:
 294         tcp_set_state(sk, TCP_CLOSE);
 295         __sk_dst_reset(sk);
 296 failure:
 297         inet->inet_dport = 0;
 298         sk->sk_route_caps = 0;
 299         return err;
 300 }
 301
 302 static void tcp_v6_mtu_reduced(struct sock *sk)
 303 {
 304         struct dst_entry *dst;
 305
 306         if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE))
 307                 return;
 308
 309         dst = inet6_csk_update_pmtu(sk, tcp_sk(sk)->mtu_info);
 310         if (!dst)
 311                 return;
 312
 313         if (inet_csk(sk)->icsk_pmtu_cookie > dst_mtu(dst)) {
 314                 tcp_sync_mss(sk, dst_mtu(dst));
 315                 tcp_simple_retransmit(sk);
 316         }
 317 }
 318
 319 static void tcp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 320                 u8 type, u8 code, int offset, __be32 info)
 321 {
 322         const struct ipv6hdr *hdr = (const struct ipv6hdr *)skb->data;
 323         const struct tcphdr *th = (struct tcphdr *)(skb->data+offset);
 324         struct net *net = dev_net(skb->dev);
 325         struct request_sock *fastopen;
 326         struct ipv6_pinfo *np;
 327         struct tcp_sock *tp;
 328         __u32 seq, snd_una;
 329         struct sock *sk;
 330         bool fatal;
 331         int err;
 332
 333         sk = __inet6_lookup_established(net, &tcp_hashinfo,
 334                                         &hdr->daddr, th->dest,
 335                                         &hdr->saddr, ntohs(th->source),
 336                                         skb->dev->ifindex);
 337
 338         if (!sk) {
 339                 __ICMP6_INC_STATS(net, __in6_dev_get(skb->dev),
 340                                   ICMP6_MIB_INERRORS);
 341                 return;
 342         }
 343
 344         if (sk->sk_state == TCP_TIME_WAIT) {
 345                 inet_twsk_put(inet_twsk(sk));
 346                 return;
 347         }
 348         seq = ntohl(th->seq);
 349         fatal = icmpv6_err_convert(type, code, &err);
 350         if (sk->sk_state == TCP_NEW_SYN_RECV)
 351                 return tcp_req_err(sk, seq, fatal);
 352
 353         bh_lock_sock(sk);
 354         if (sock_owned_by_user(sk) && type != ICMPV6_PKT_TOOBIG)
 355                 __NET_INC_STATS(net, LINUX_MIB_LOCKDROPPEDICMPS);
 356
 357         if (sk->sk_state == TCP_CLOSE)
 358                 goto out;
 359
 360         if (ipv6_hdr(skb)->hop_limit < inet6_sk(sk)->min_hopcount) {
 361                 __NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP);
 362                 goto out;
 363         }
 364
 365         tp = tcp_sk(sk);
 366         /* XXX (TFO) - tp->snd_una should be ISN (tcp_create_openreq_child() */
 367         fastopen = tp->fastopen_rsk;
 368         snd_una = fastopen ? tcp_rsk(fastopen)->snt_isn : tp->snd_una;
 369         if (sk->sk_state != TCP_LISTEN &&
 370             !between(seq, snd_una, tp->snd_nxt)) {
 371                 __NET_INC_STATS(net, LINUX_MIB_OUTOFWINDOWICMPS);
 372                 goto out;
 373         }
 374
 375         np = inet6_sk(sk);
 376
 377         if (type == NDISC_REDIRECT) {
 378                 struct dst_entry *dst = __sk_dst_check(sk, np->dst_cookie);
 379
 380                 if (dst)
 381                         dst->ops->redirect(dst, sk, skb);
 382                 goto out;
 383         }
 384
 385         if (type == ICMPV6_PKT_TOOBIG) {
 386                 /* We are not interested in TCP_LISTEN and open_requests
 387                  * (SYN-ACKs send out by Linux are always <576bytes so
 388                  * they should go through unfragmented).
 389                  */
 390                 if (sk->sk_state == TCP_LISTEN)
 391                         goto out;
 392
 393                 if (!ip6_sk_accept_pmtu(sk))
 394                         goto out;
 395
 396                 tp->mtu_info = ntohl(info);
 397                 if (!sock_owned_by_user(sk))
 398                         tcp_v6_mtu_reduced(sk);
 399                 else if (!test_and_set_bit(TCP_MTU_REDUCED_DEFERRED,
 400                                            &tp->tsq_flags))
 401                         sock_hold(sk);
 402                 goto out;
 403         }
 404
 405
 406         /* Might be for an request_sock */
 407         switch (sk->sk_state) {
 408         case TCP_SYN_SENT:
 409         case TCP_SYN_RECV:
 410                 /* Only in fast or simultaneous open. If a fast open socket is
 411                  * is already accepted it is treated as a connected one below.
 412                  */
 413                 if (fastopen && !fastopen->sk)
 414                         break;
 415
 416                 if (!sock_owned_by_user(sk)) {
 417                         sk->sk_err = err;
 418                         sk->sk_error_report(sk);                /* Wake people up to see the error (see connect in sock.c) */
 419
 420                         tcp_done(sk);
 421                 } else
 422                         sk->sk_err_soft = err;
 423                 goto out;
 424         }
 425
 426         if (!sock_owned_by_user(sk) && np->recverr) {
 427                 sk->sk_err = err;
 428                 sk->sk_error_report(sk);
 429         } else
 430                 sk->sk_err_soft = err;
 431
 432 out:
 433         bh_unlock_sock(sk);
 434         sock_put(sk);
 435 }
 436
 437
 438 static int tcp_v6_send_synack(const struct sock *sk, struct dst_entry *dst,
 439                               struct flowi *fl,
 440                               struct request_sock *req,
 441                               struct tcp_fastopen_cookie *foc,
 442                               enum tcp_synack_type synack_type)
 443 {
 444         struct inet_request_sock *ireq = inet_rsk(req);
 445         struct ipv6_pinfo *np = inet6_sk(sk);
 446         struct ipv6_txoptions *opt;
 447         struct flowi6 *fl6 = &fl->u.ip6;
 448         struct sk_buff *skb;
 449         int err = -ENOMEM;
 450
 451         /* First, grab a route. */
 452         if (!dst && (dst = inet6_csk_route_req(sk, fl6, req,
 453                                                IPPROTO_TCP)) == NULL)
 454                 goto done;
 455
 456         skb = tcp_make_synack(sk, dst, req, foc, synack_type);
 457
 458         if (skb) {
 459                 __tcp_v6_send_check(skb, &ireq->ir_v6_loc_addr,
 460                                     &ireq->ir_v6_rmt_addr);
 461
 462                 fl6->daddr = ireq->ir_v6_rmt_addr;
 463                 if (np->repflow && ireq->pktopts)
 464                         fl6->flowlabel = ip6_flowlabel(ipv6_hdr(ireq->pktopts));
 465
 466                 rcu_read_lock();
 467                 opt = ireq->ipv6_opt;
 468                 if (!opt)
 469                         opt = rcu_dereference(np->opt);
 470                 err = ip6_xmit(sk, skb, fl6, opt, np->tclass);
 471                 rcu_read_unlock();
 472                 err = net_xmit_eval(err);
 473         }
 474
 475 done:
 476         return err;
 477 }
 478
 479
 480 static void tcp_v6_reqsk_destructor(struct request_sock *req)
 481 {
 482         kfree(inet_rsk(req)->ipv6_opt);
 483         kfree_skb(inet_rsk(req)->pktopts);
 484 }
 485
 486 #ifdef CONFIG_TCP_MD5SIG
 487 static struct tcp_md5sig_key *tcp_v6_md5_do_lookup(const struct sock *sk,
 488                                                    const struct in6_addr *addr)
 489 {
 490         return tcp_md5_do_lookup(sk, (union tcp_md5_addr *)addr, AF_INET6);
 491 }
 492
 493 static struct tcp_md5sig_key *tcp_v6_md5_lookup(const struct sock *sk,
 494                                                 const struct sock *addr_sk)
 495 {
 496         return tcp_v6_md5_do_lookup(sk, &addr_sk->sk_v6_daddr);
 497 }
 498
 499 static int tcp_v6_parse_md5_keys(struct sock *sk, char __user *optval,
 500                                  int optlen)
 501 {
 502         struct tcp_md5sig cmd;
 503         struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)&cmd.tcpm_addr;
 504
 505         if (optlen < sizeof(cmd))
 506                 return -EINVAL;
 507
 508         if (copy_from_user(&cmd, optval, sizeof(cmd)))
 509                 return -EFAULT;
 510
 511         if (sin6->sin6_family != AF_INET6)
 512                 return -EINVAL;
 513
 514         if (!cmd.tcpm_keylen) {
 515                 if (ipv6_addr_v4mapped(&sin6->sin6_addr))
 516                         return tcp_md5_do_del(sk, (union tcp_md5_addr *)&sin6->sin6_addr.s6_addr32[3],
 517                                               AF_INET);
 518                 return tcp_md5_do_del(sk, (union tcp_md5_addr *)&sin6->sin6_addr,
 519                                       AF_INET6);
 520         }
 521
 522         if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN)
 523                 return -EINVAL;
 524
 525         if (ipv6_addr_v4mapped(&sin6->sin6_addr))
 526                 return tcp_md5_do_add(sk, (union tcp_md5_addr *)&sin6->sin6_addr.s6_addr32[3],
 527                                       AF_INET, cmd.tcpm_key, cmd.tcpm_keylen, GFP_KERNEL);
 528
 529         return tcp_md5_do_add(sk, (union tcp_md5_addr *)&sin6->sin6_addr,
 530                               AF_INET6, cmd.tcpm_key, cmd.tcpm_keylen, GFP_KERNEL);
 531 }
 532
 533 static int tcp_v6_md5_hash_pseudoheader(struct tcp_md5sig_pool *hp,
 534                                         const struct in6_addr *daddr,
 535                                         const struct in6_addr *saddr, int nbytes)
 536 {
 537         struct tcp6_pseudohdr *bp;
 538         struct scatterlist sg;
 539
 540         bp = &hp->md5_blk.ip6;
 541         /* 1. TCP pseudo-header (RFC2460) */
 542         bp->saddr = *saddr;
 543         bp->daddr = *daddr;
 544         bp->protocol = cpu_to_be32(IPPROTO_TCP);
 545         bp->len = cpu_to_be32(nbytes);
 546
 547         sg_init_one(&sg, bp, sizeof(*bp));
 548         ahash_request_set_crypt(hp->md5_req, &sg, NULL, sizeof(*bp));
 549         return crypto_ahash_update(hp->md5_req);
 550 }
 551
 552 static int tcp_v6_md5_hash_hdr(char *md5_hash, struct tcp_md5sig_key *key,
 553                                const struct in6_addr *daddr, struct in6_addr *saddr,
 554                                const struct tcphdr *th)
 555 {
 556         struct tcp_md5sig_pool *hp;
 557         struct ahash_request *req;
 558
 559         hp = tcp_get_md5sig_pool();
 560         if (!hp)
 561                 goto clear_hash_noput;
 562         req = hp->md5_req;
 563
 564         if (crypto_ahash_init(req))
 565                 goto clear_hash;
 566         if (tcp_v6_md5_hash_pseudoheader(hp, daddr, saddr, th->doff << 2))
 567                 goto clear_hash;
 568         if (tcp_md5_hash_header(hp, th))
 569                 goto clear_hash;
 570         if (tcp_md5_hash_key(hp, key))
 571                 goto clear_hash;
 572         ahash_request_set_crypt(req, NULL, md5_hash, 0);
 573         if (crypto_ahash_final(req))
 574                 goto clear_hash;
 575
 576         tcp_put_md5sig_pool();
 577         return 0;
 578
 579 clear_hash:
 580         tcp_put_md5sig_pool();
 581 clear_hash_noput:
 582         memset(md5_hash, 0, 16);
 583         return 1;
 584 }
 585
 586 static int tcp_v6_md5_hash_skb(char *md5_hash,
 587                                const struct tcp_md5sig_key *key,
 588                                const struct sock *sk,
 589                                const struct sk_buff *skb)
 590 {
 591         const struct in6_addr *saddr, *daddr;
 592         struct tcp_md5sig_pool *hp;
 593         struct ahash_request *req;
 594         const struct tcphdr *th = tcp_hdr(skb);
 595
 596         if (sk) { /* valid for establish/request sockets */
 597                 saddr = &sk->sk_v6_rcv_saddr;
 598                 daddr = &sk->sk_v6_daddr;
 599         } else {
 600                 const struct ipv6hdr *ip6h = ipv6_hdr(skb);
 601                 saddr = &ip6h->saddr;
 602                 daddr = &ip6h->daddr;
 603         }
 604
 605         hp = tcp_get_md5sig_pool();
 606         if (!hp)
 607                 goto clear_hash_noput;
 608         req = hp->md5_req;
 609
 610         if (crypto_ahash_init(req))
 611                 goto clear_hash;
 612
 613         if (tcp_v6_md5_hash_pseudoheader(hp, daddr, saddr, skb->len))
 614                 goto clear_hash;
 615         if (tcp_md5_hash_header(hp, th))
 616                 goto clear_hash;
 617         if (tcp_md5_hash_skb_data(hp, skb, th->doff << 2))
 618                 goto clear_hash;
 619         if (tcp_md5_hash_key(hp, key))
 620                 goto clear_hash;
 621         ahash_request_set_crypt(req, NULL, md5_hash, 0);
 622         if (crypto_ahash_final(req))
 623                 goto clear_hash;
 624
 625         tcp_put_md5sig_pool();
 626         return 0;
 627
 628 clear_hash:
 629         tcp_put_md5sig_pool();
 630 clear_hash_noput:
 631         memset(md5_hash, 0, 16);
 632         return 1;
 633 }
 634
 635 #endif
 636
 637 static bool tcp_v6_inbound_md5_hash(const struct sock *sk,
 638                                     const struct sk_buff *skb)
 639 {
 640 #ifdef CONFIG_TCP_MD5SIG
 641         const __u8 *hash_location = NULL;
 642         struct tcp_md5sig_key *hash_expected;
 643         const struct ipv6hdr *ip6h = ipv6_hdr(skb);
 644         const struct tcphdr *th = tcp_hdr(skb);
 645         int genhash;
 646         u8 newhash[16];
 647
 648         hash_expected = tcp_v6_md5_do_lookup(sk, &ip6h->saddr);
 649         hash_location = tcp_parse_md5sig_option(th);
 650
 651         /* We've parsed the options - do we have a hash? */
 652         if (!hash_expected && !hash_location)
 653                 return false;
 654
 655         if (hash_expected && !hash_location) {
 656                 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5NOTFOUND);
 657                 return true;
 658         }
 659
 660         if (!hash_expected && hash_location) {
 661                 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5UNEXPECTED);
 662                 return true;
 663         }
 664
 665         /* check the signature */
 666         genhash = tcp_v6_md5_hash_skb(newhash,
 667                                       hash_expected,
 668                                       NULL, skb);
 669
 670         if (genhash || memcmp(hash_location, newhash, 16) != 0) {
 671                 net_info_ratelimited("MD5 Hash %s for [%pI6c]:%u->[%pI6c]:%u\n",
 672                                      genhash ? "failed" : "mismatch",
 673                                      &ip6h->saddr, ntohs(th->source),
 674                                      &ip6h->daddr, ntohs(th->dest));
 675                 return true;
 676         }
 677 #endif
 678         return false;
 679 }
 680
 681 static void tcp_v6_init_req(struct request_sock *req,
 682                             const struct sock *sk_listener,
 683                             struct sk_buff *skb)
 684 {
 685         struct inet_request_sock *ireq = inet_rsk(req);
 686         const struct ipv6_pinfo *np = inet6_sk(sk_listener);
 687
 688         ireq->ir_v6_rmt_addr = ipv6_hdr(skb)->saddr;
 689         ireq->ir_v6_loc_addr = ipv6_hdr(skb)->daddr;
 690
 691         /* So that link locals have meaning */
 692         if (!sk_listener->sk_bound_dev_if &&
 693             ipv6_addr_type(&ireq->ir_v6_rmt_addr) & IPV6_ADDR_LINKLOCAL)
 694                 ireq->ir_iif = tcp_v6_iif(skb);
 695
 696         if (!TCP_SKB_CB(skb)->tcp_tw_isn &&
 697             (ipv6_opt_accepted(sk_listener, skb, &TCP_SKB_CB(skb)->header.h6) ||
 698              np->rxopt.bits.rxinfo ||
 699              np->rxopt.bits.rxoinfo || np->rxopt.bits.rxhlim ||
 700              np->rxopt.bits.rxohlim || np->repflow)) {
 701                 atomic_inc(&skb->users);
 702                 ireq->pktopts = skb;
 703         }
 704 }
 705
 706 static struct dst_entry *tcp_v6_route_req(const struct sock *sk,
 707                                           struct flowi *fl,
 708                                           const struct request_sock *req,
 709                                           bool *strict)
 710 {
 711         if (strict)
 712                 *strict = true;
 713         return inet6_csk_route_req(sk, &fl->u.ip6, req, IPPROTO_TCP);
 714 }
 715
 716 struct request_sock_ops tcp6_request_sock_ops __read_mostly = {
 717         .family         =       AF_INET6,
 718         .obj_size       =       sizeof(struct tcp6_request_sock),
 719         .rtx_syn_ack    =       tcp_rtx_synack,
 720         .send_ack       =       tcp_v6_reqsk_send_ack,
 721         .destructor     =       tcp_v6_reqsk_destructor,
 722         .send_reset     =       tcp_v6_send_reset,
 723         .syn_ack_timeout =      tcp_syn_ack_timeout,
 724 };
 725
 726 static const struct tcp_request_sock_ops tcp_request_sock_ipv6_ops = {
 727         .mss_clamp      =       IPV6_MIN_MTU - sizeof(struct tcphdr) -
 728                                 sizeof(struct ipv6hdr),
 729 #ifdef CONFIG_TCP_MD5SIG
 730         .req_md5_lookup =       tcp_v6_md5_lookup,
 731         .calc_md5_hash  =       tcp_v6_md5_hash_skb,
 732 #endif
 733         .init_req       =       tcp_v6_init_req,
 734 #ifdef CONFIG_SYN_COOKIES
 735         .cookie_init_seq =      cookie_v6_init_sequence,
 736 #endif
 737         .route_req      =       tcp_v6_route_req,
 738         .init_seq       =       tcp_v6_init_sequence,
 739         .send_synack    =       tcp_v6_send_synack,
 740 };
 741
 742 static void tcp_v6_send_response(const struct sock *sk, struct sk_buff *skb, u32 seq,
 743                                  u32 ack, u32 win, u32 tsval, u32 tsecr,
 744                                  int oif, struct tcp_md5sig_key *key, int rst,
 745                                  u8 tclass, u32 label)
 746 {
 747         const struct tcphdr *th = tcp_hdr(skb);
 748         struct tcphdr *t1;
 749         struct sk_buff *buff;
 750         struct flowi6 fl6;
 751         struct net *net = sk ? sock_net(sk) : dev_net(skb_dst(skb)->dev);
 752         struct sock *ctl_sk = net->ipv6.tcp_sk;
 753         unsigned int tot_len = sizeof(struct tcphdr);
 754         struct dst_entry *dst;
 755         __be32 *topt;
 756
 757         if (tsecr)
 758                 tot_len += TCPOLEN_TSTAMP_ALIGNED;
 759 #ifdef CONFIG_TCP_MD5SIG
 760         if (key)
 761                 tot_len += TCPOLEN_MD5SIG_ALIGNED;
 762 #endif
 763
 764         buff = alloc_skb(MAX_HEADER + sizeof(struct ipv6hdr) + tot_len,
 765                          GFP_ATOMIC);
 766         if (!buff)
 767                 return;
 768
 769         skb_reserve(buff, MAX_HEADER + sizeof(struct ipv6hdr) + tot_len);
 770
 771         t1 = (struct tcphdr *) skb_push(buff, tot_len);
 772         skb_reset_transport_header(buff);
 773
 774         /* Swap the send and the receive. */
 775         memset(t1, 0, sizeof(*t1));
 776         t1->dest = th->source;
 777         t1->source = th->dest;
 778         t1->doff = tot_len / 4;
 779         t1->seq = htonl(seq);
 780         t1->ack_seq = htonl(ack);
 781         t1->ack = !rst || !th->ack;
 782         t1->rst = rst;
 783         t1->window = htons(win);
 784
 785         topt = (__be32 *)(t1 + 1);
 786
 787         if (tsecr) {
 788                 *topt++ = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
 789                                 (TCPOPT_TIMESTAMP << 8) | TCPOLEN_TIMESTAMP);
 790                 *topt++ = htonl(tsval);
 791                 *topt++ = htonl(tsecr);
 792         }
 793
 794 #ifdef CONFIG_TCP_MD5SIG
 795         if (key) {
 796                 *topt++ = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
 797                                 (TCPOPT_MD5SIG << 8) | TCPOLEN_MD5SIG);
 798                 tcp_v6_md5_hash_hdr((__u8 *)topt, key,
 799                                     &ipv6_hdr(skb)->saddr,
 800                                     &ipv6_hdr(skb)->daddr, t1);
 801         }
 802 #endif
 803
 804         memset(&fl6, 0, sizeof(fl6));
 805         fl6.daddr = ipv6_hdr(skb)->saddr;
 806         fl6.saddr = ipv6_hdr(skb)->daddr;
 807         fl6.flowlabel = label;
 808
 809         buff->ip_summed = CHECKSUM_PARTIAL;
 810         buff->csum = 0;
 811
 812         __tcp_v6_send_check(buff, &fl6.saddr, &fl6.daddr);
 813
 814         fl6.flowi6_proto = IPPROTO_TCP;
 815         if (rt6_need_strict(&fl6.daddr) && !oif)
 816                 fl6.flowi6_oif = tcp_v6_iif(skb);
 817         else {
 818                 if (!oif && netif_index_is_l3_master(net, skb->skb_iif))
 819                         oif = skb->skb_iif;
 820
 821                 fl6.flowi6_oif = oif;
 822         }
 823
 824         fl6.flowi6_mark = IP6_REPLY_MARK(net, skb->mark);
 825         fl6.fl6_dport = t1->dest;
 826         fl6.fl6_sport = t1->source;
 827         security_skb_classify_flow(skb, flowi6_to_flowi(&fl6));
 828
 829         /* Pass a socket to ip6_dst_lookup either it is for RST
 830          * Underlying function will use this to retrieve the network
 831          * namespace
 832          */
 833         dst = ip6_dst_lookup_flow(ctl_sk, &fl6, NULL);
 834         if (!IS_ERR(dst)) {
 835                 skb_dst_set(buff, dst);
 836                 ip6_xmit(ctl_sk, buff, &fl6, NULL, tclass);
 837                 TCP_INC_STATS(net, TCP_MIB_OUTSEGS);
 838                 if (rst)
 839                         TCP_INC_STATS(net, TCP_MIB_OUTRSTS);
 840                 return;
 841         }
 842
 843         kfree_skb(buff);
 844 }
 845
 846 static void tcp_v6_send_reset(const struct sock *sk, struct sk_buff *skb)
 847 {
 848         const struct tcphdr *th = tcp_hdr(skb);
 849         u32 seq = 0, ack_seq = 0;
 850         struct tcp_md5sig_key *key = NULL;
 851 #ifdef CONFIG_TCP_MD5SIG
 852         const __u8 *hash_location = NULL;
 853         struct ipv6hdr *ipv6h = ipv6_hdr(skb);
 854         unsigned char newhash[16];
 855         int genhash;
 856         struct sock *sk1 = NULL;
 857 #endif
 858         int oif;
 859
 860         if (th->rst)
 861                 return;
 862
 863         /* If sk not NULL, it means we did a successful lookup and incoming
 864          * route had to be correct. prequeue might have dropped our dst.
 865          */
 866         if (!sk && !ipv6_unicast_destination(skb))
 867                 return;
 868
 869 #ifdef CONFIG_TCP_MD5SIG
 870         rcu_read_lock();
 871         hash_location = tcp_parse_md5sig_option(th);
 872         if (sk && sk_fullsock(sk)) {
 873                 key = tcp_v6_md5_do_lookup(sk, &ipv6h->saddr);
 874         } else if (hash_location) {
 875                 /*
 876                  * active side is lost. Try to find listening socket through
 877                  * source port, and then find md5 key through listening socket.
 878                  * we are not loose security here:
 879                  * Incoming packet is checked with md5 hash with finding key,
 880                  * no RST generated if md5 hash doesn't match.
 881                  */
 882                 sk1 = inet6_lookup_listener(dev_net(skb_dst(skb)->dev),
 883                                            &tcp_hashinfo, NULL, 0,
 884                                            &ipv6h->saddr,
 885                                            th->source, &ipv6h->daddr,
 886                                            ntohs(th->source), tcp_v6_iif(skb));
 887                 if (!sk1)
 888                         goto out;
 889
 890                 key = tcp_v6_md5_do_lookup(sk1, &ipv6h->saddr);
 891                 if (!key)
 892                         goto out;
 893
 894                 genhash = tcp_v6_md5_hash_skb(newhash, key, NULL, skb);
 895                 if (genhash || memcmp(hash_location, newhash, 16) != 0)
 896                         goto out;
 897         }
 898 #endif
 899
 900         if (th->ack)
 901                 seq = ntohl(th->ack_seq);
 902         else
 903                 ack_seq = ntohl(th->seq) + th->syn + th->fin + skb->len -
 904                           (th->doff << 2);
 905
 906         oif = sk ? sk->sk_bound_dev_if : 0;
 907         tcp_v6_send_response(sk, skb, seq, ack_seq, 0, 0, 0, oif, key, 1, 0, 0);
 908
 909 #ifdef CONFIG_TCP_MD5SIG
 910 out:
 911         rcu_read_unlock();
 912 #endif
 913 }
 914
 915 static void tcp_v6_send_ack(const struct sock *sk, struct sk_buff *skb, u32 seq,
 916                             u32 ack, u32 win, u32 tsval, u32 tsecr, int oif,
 917                             struct tcp_md5sig_key *key, u8 tclass,
 918                             u32 label)
 919 {
 920         tcp_v6_send_response(sk, skb, seq, ack, win, tsval, tsecr, oif, key, 0,
 921                              tclass, label);
 922 }
 923
 924 static void tcp_v6_timewait_ack(struct sock *sk, struct sk_buff *skb)
 925 {
 926         struct inet_timewait_sock *tw = inet_twsk(sk);
 927         struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
 928
 929         tcp_v6_send_ack(sk, skb, tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
 930                         tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
 931                         tcp_time_stamp + tcptw->tw_ts_offset,
 932                         tcptw->tw_ts_recent, tw->tw_bound_dev_if, tcp_twsk_md5_key(tcptw),
 933                         tw->tw_tclass, cpu_to_be32(tw->tw_flowlabel));
 934
 935         inet_twsk_put(tw);
 936 }
 937
 938 static void tcp_v6_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb,
 939                                   struct request_sock *req)
 940 {
 941         /* sk->sk_state == TCP_LISTEN -> for regular TCP_SYN_RECV
 942          * sk->sk_state == TCP_SYN_RECV -> for Fast Open.
 943          */
 944         tcp_v6_send_ack(sk, skb, (sk->sk_state == TCP_LISTEN) ?
 945                         tcp_rsk(req)->snt_isn + 1 : tcp_sk(sk)->snd_nxt,
 946                         tcp_rsk(req)->rcv_nxt, req->rsk_rcv_wnd,
 947                         tcp_time_stamp, req->ts_recent, sk->sk_bound_dev_if,
 948                         tcp_v6_md5_do_lookup(sk, &ipv6_hdr(skb)->daddr),
 949                         0, 0);
 950 }
 951
 952
 953 static struct sock *tcp_v6_cookie_check(struct sock *sk, struct sk_buff *skb)
 954 {
 955 #ifdef CONFIG_SYN_COOKIES
 956         const struct tcphdr *th = tcp_hdr(skb);
 957
 958         if (!th->syn)
 959                 sk = cookie_v6_check(sk, skb);
 960 #endif
 961         return sk;
 962 }
 963
 964 static int tcp_v6_conn_request(struct sock *sk, struct sk_buff *skb)
 965 {
 966         if (skb->protocol == htons(ETH_P_IP))
 967                 return tcp_v4_conn_request(sk, skb);
 968
 969         if (!ipv6_unicast_destination(skb))
 970                 goto drop;
 971
 972         return tcp_conn_request(&tcp6_request_sock_ops,
 973                                 &tcp_request_sock_ipv6_ops, sk, skb);
 974
 975 drop:
 976         tcp_listendrop(sk);
 977         return 0; /* don't send reset */
 978 }
 979
 980 static struct sock *tcp_v6_syn_recv_sock(const struct sock *sk, struct sk_buff *skb,
 981                                          struct request_sock *req,
 982                                          struct dst_entry *dst,
 983                                          struct request_sock *req_unhash,
 984                                          bool *own_req)
 985 {
 986         struct inet_request_sock *ireq;
 987         struct ipv6_pinfo *newnp;
 988         const struct ipv6_pinfo *np = inet6_sk(sk);
 989         struct ipv6_txoptions *opt;
 990         struct tcp6_sock *newtcp6sk;
 991         struct inet_sock *newinet;
 992         struct tcp_sock *newtp;
 993         struct sock *newsk;
 994 #ifdef CONFIG_TCP_MD5SIG
 995         struct tcp_md5sig_key *key;
 996 #endif
 997         struct flowi6 fl6;
 998
 999         if (skb->protocol == htons(ETH_P_IP)) {
1000                 /*
1001                  *      v6 mapped
1002                  */
1003
1004                 newsk = tcp_v4_syn_recv_sock(sk, skb, req, dst,
1005                                              req_unhash, own_req);
1006
1007                 if (!newsk)
1008                         return NULL;
1009
1010                 newtcp6sk = (struct tcp6_sock *)newsk;
1011                 inet_sk(newsk)->pinet6 = &newtcp6sk->inet6;
1012
1013                 newinet = inet_sk(newsk);
1014                 newnp = inet6_sk(newsk);
1015                 newtp = tcp_sk(newsk);
1016
1017                 memcpy(newnp, np, sizeof(struct ipv6_pinfo));
1018
1019                 newnp->saddr = newsk->sk_v6_rcv_saddr;
1020
1021                 inet_csk(newsk)->icsk_af_ops = &ipv6_mapped;
1022                 newsk->sk_backlog_rcv = tcp_v4_do_rcv;
1023 #ifdef CONFIG_TCP_MD5SIG
1024                 newtp->af_specific = &tcp_sock_ipv6_mapped_specific;
1025 #endif
1026
1027                 newnp->ipv6_ac_list = NULL;
1028                 newnp->ipv6_fl_list = NULL;
1029                 newnp->pktoptions  = NULL;
1030                 newnp->opt         = NULL;
1031                 newnp->mcast_oif   = tcp_v6_iif(skb);
1032                 newnp->mcast_hops  = ipv6_hdr(skb)->hop_limit;
1033                 newnp->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(skb));
1034                 if (np->repflow)
1035                         newnp->flow_label = ip6_flowlabel(ipv6_hdr(skb));
1036
1037                 /*
1038                  * No need to charge this sock to the relevant IPv6 refcnt debug socks count
1039                  * here, tcp_create_openreq_child now does this for us, see the comment in
1040                  * that function for the gory details. -acme
1041                  */
1042
1043                 /* It is tricky place. Until this moment IPv4 tcp
1044                    worked with IPv6 icsk.icsk_af_ops.
1045                    Sync it now.
1046                  */
1047                 tcp_sync_mss(newsk, inet_csk(newsk)->icsk_pmtu_cookie);
1048
1049                 return newsk;
1050         }
1051
1052         ireq = inet_rsk(req);
1053
1054         if (sk_acceptq_is_full(sk))
1055                 goto out_overflow;
1056
1057         if (!dst) {
1058                 dst = inet6_csk_route_req(sk, &fl6, req, IPPROTO_TCP);
1059                 if (!dst)
1060                         goto out;
1061         }
1062
1063         newsk = tcp_create_openreq_child(sk, req, skb);
1064         if (!newsk)
1065                 goto out_nonewsk;
1066
1067         /*
1068          * No need to charge this sock to the relevant IPv6 refcnt debug socks
1069          * count here, tcp_create_openreq_child now does this for us, see the
1070          * comment in that function for the gory details. -acme
1071          */
1072
1073         newsk->sk_gso_type = SKB_GSO_TCPV6;
1074         ip6_dst_store(newsk, dst, NULL, NULL);
1075         inet6_sk_rx_dst_set(newsk, skb);
1076
1077         newtcp6sk = (struct tcp6_sock *)newsk;
1078         inet_sk(newsk)->pinet6 = &newtcp6sk->inet6;
1079
1080         newtp = tcp_sk(newsk);
1081         newinet = inet_sk(newsk);
1082         newnp = inet6_sk(newsk);
1083
1084         memcpy(newnp, np, sizeof(struct ipv6_pinfo));
1085
1086         newsk->sk_v6_daddr = ireq->ir_v6_rmt_addr;
1087         newnp->saddr = ireq->ir_v6_loc_addr;
1088         newsk->sk_v6_rcv_saddr = ireq->ir_v6_loc_addr;
1089         newsk->sk_bound_dev_if = ireq->ir_iif;
1090
1091         /* Now IPv6 options...
1092
1093            First: no IPv4 options.
1094          */
1095         newinet->inet_opt = NULL;
1096         newnp->ipv6_ac_list = NULL;
1097         newnp->ipv6_fl_list = NULL;
1098
1099         /* Clone RX bits */
1100         newnp->rxopt.all = np->rxopt.all;
1101
1102         newnp->pktoptions = NULL;
1103         newnp->opt        = NULL;
1104         newnp->mcast_oif  = tcp_v6_iif(skb);
1105         newnp->mcast_hops = ipv6_hdr(skb)->hop_limit;
1106         newnp->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(skb));
1107         if (np->repflow)
1108                 newnp->flow_label = ip6_flowlabel(ipv6_hdr(skb));
1109
1110         /* Clone native IPv6 options from listening socket (if any)
1111
1112            Yes, keeping reference count would be much more clever,
1113            but we make one more one thing there: reattach optmem
1114            to newsk.
1115          */
1116         opt = ireq->ipv6_opt;
1117         if (!opt)
1118                 opt = rcu_dereference(np->opt);
1119         if (opt) {
1120                 opt = ipv6_dup_options(newsk, opt);
1121                 RCU_INIT_POINTER(newnp->opt, opt);
1122         }
1123         inet_csk(newsk)->icsk_ext_hdr_len = 0;
1124         if (opt)
1125                 inet_csk(newsk)->icsk_ext_hdr_len = opt->opt_nflen +
1126                                                     opt->opt_flen;
1127
1128         tcp_ca_openreq_child(newsk, dst);
1129
1130         tcp_sync_mss(newsk, dst_mtu(dst));
1131         newtp->advmss = dst_metric_advmss(dst);
1132         if (tcp_sk(sk)->rx_opt.user_mss &&
1133             tcp_sk(sk)->rx_opt.user_mss < newtp->advmss)
1134                 newtp->advmss = tcp_sk(sk)->rx_opt.user_mss;
1135
1136         tcp_initialize_rcv_mss(newsk);
1137
1138         newinet->inet_daddr = newinet->inet_saddr = LOOPBACK4_IPV6;
1139         newinet->inet_rcv_saddr = LOOPBACK4_IPV6;
1140
1141 #ifdef CONFIG_TCP_MD5SIG
1142         /* Copy over the MD5 key from the original socket */
1143         key = tcp_v6_md5_do_lookup(sk, &newsk->sk_v6_daddr);
1144         if (key) {
1145                 /* We're using one, so create a matching key
1146                  * on the newsk structure. If we fail to get
1147                  * memory, then we end up not copying the key
1148                  * across. Shucks.
1149                  */
1150                 tcp_md5_do_add(newsk, (union tcp_md5_addr *)&newsk->sk_v6_daddr,
1151                                AF_INET6, key->key, key->keylen,
1152                                sk_gfp_mask(sk, GFP_ATOMIC));
1153         }
1154 #endif
1155
1156         if (__inet_inherit_port(sk, newsk) < 0) {
1157                 inet_csk_prepare_forced_close(newsk);
1158                 tcp_done(newsk);
1159                 goto out;
1160         }
1161         *own_req = inet_ehash_nolisten(newsk, req_to_sk(req_unhash));
1162         if (*own_req) {
1163                 tcp_move_syn(newtp, req);
1164
1165                 /* Clone pktoptions received with SYN, if we own the req */
1166                 if (ireq->pktopts) {
1167                         newnp->pktoptions = skb_clone(ireq->pktopts,
1168                                                       sk_gfp_mask(sk, GFP_ATOMIC));
1169                         consume_skb(ireq->pktopts);
1170                         ireq->pktopts = NULL;
1171                         if (newnp->pktoptions)
1172                                 skb_set_owner_r(newnp->pktoptions, newsk);
1173                 }
1174         }
1175
1176         return newsk;
1177
1178 out_overflow:
1179         __NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
1180 out_nonewsk:
1181         dst_release(dst);
1182 out:
1183         tcp_listendrop(sk);
1184         return NULL;
1185 }
1186
1187 /* The socket must have it's spinlock held when we get
1188  * here, unless it is a TCP_LISTEN socket.
1189  *
1190  * We have a potential double-lock case here, so even when
1191  * doing backlog processing we use the BH locking scheme.
1192  * This is because we cannot sleep with the original spinlock
1193  * held.
1194  */
1195 static int tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb)
1196 {
1197         struct ipv6_pinfo *np = inet6_sk(sk);
1198         struct tcp_sock *tp;
1199         struct sk_buff *opt_skb = NULL;
1200
1201         /* Imagine: socket is IPv6. IPv4 packet arrives,
1202            goes to IPv4 receive handler and backlogged.
1203            From backlog it always goes here. Kerboom...
1204            Fortunately, tcp_rcv_established and rcv_established
1205            handle them correctly, but it is not case with
1206            tcp_v6_hnd_req and tcp_v6_send_reset().   --ANK
1207          */
1208
1209         if (skb->protocol == htons(ETH_P_IP))
1210                 return tcp_v4_do_rcv(sk, skb);
1211
1212         if (sk_filter(sk, skb))
1213                 goto discard;
1214
1215         /*
1216          *      socket locking is here for SMP purposes as backlog rcv
1217          *      is currently called with bh processing disabled.
1218          */
1219
1220         /* Do Stevens' IPV6_PKTOPTIONS.
1221
1222            Yes, guys, it is the only place in our code, where we
1223            may make it not affecting IPv4.
1224            The rest of code is protocol independent,
1225            and I do not like idea to uglify IPv4.
1226
1227            Actually, all the idea behind IPV6_PKTOPTIONS
1228            looks not very well thought. For now we latch
1229            options, received in the last packet, enqueued
1230            by tcp. Feel free to propose better solution.
1231                                                --ANK (980728)
1232          */
1233         if (np->rxopt.all)
1234                 opt_skb = skb_clone(skb, sk_gfp_mask(sk, GFP_ATOMIC));
1235
1236         if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
1237                 struct dst_entry *dst = sk->sk_rx_dst;
1238
1239                 sock_rps_save_rxhash(sk, skb);
1240                 sk_mark_napi_id(sk, skb);
1241                 if (dst) {
1242                         if (inet_sk(sk)->rx_dst_ifindex != skb->skb_iif ||
1243                             dst->ops->check(dst, np->rx_dst_cookie) == NULL) {
1244                                 dst_release(dst);
1245                                 sk->sk_rx_dst = NULL;
1246                         }
1247                 }
1248
1249                 tcp_rcv_established(sk, skb, tcp_hdr(skb), skb->len);
1250                 if (opt_skb)
1251                         goto ipv6_pktoptions;
1252                 return 0;
1253         }
1254
1255         if (tcp_checksum_complete(skb))
1256                 goto csum_err;
1257
1258         if (sk->sk_state == TCP_LISTEN) {
1259                 struct sock *nsk = tcp_v6_cookie_check(sk, skb);
1260
1261                 if (!nsk)
1262                         goto discard;
1263
1264                 if (nsk != sk) {
1265                         sock_rps_save_rxhash(nsk, skb);
1266                         sk_mark_napi_id(nsk, skb);
1267                         if (tcp_child_process(sk, nsk, skb))
1268                                 goto reset;
1269                         if (opt_skb)
1270                                 __kfree_skb(opt_skb);
1271                         return 0;
1272                 }
1273         } else
1274                 sock_rps_save_rxhash(sk, skb);
1275
1276         if (tcp_rcv_state_process(sk, skb))
1277                 goto reset;
1278         if (opt_skb)
1279                 goto ipv6_pktoptions;
1280         return 0;
1281
1282 reset:
1283         tcp_v6_send_reset(sk, skb);
1284 discard:
1285         if (opt_skb)
1286                 __kfree_skb(opt_skb);
1287         kfree_skb(skb);
1288         return 0;
1289 csum_err:
1290         TCP_INC_STATS(sock_net(sk), TCP_MIB_CSUMERRORS);
1291         TCP_INC_STATS(sock_net(sk), TCP_MIB_INERRS);
1292         goto discard;
1293
1294
1295 ipv6_pktoptions:
1296         /* Do you ask, what is it?
1297
1298            1. skb was enqueued by tcp.
1299            2. skb is added to tail of read queue, rather than out of order.
1300            3. socket is not in passive state.
1301            4. Finally, it really contains options, which user wants to receive.
1302          */
1303         tp = tcp_sk(sk);
1304         if (TCP_SKB_CB(opt_skb)->end_seq == tp->rcv_nxt &&
1305             !((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN))) {
1306                 if (np->rxopt.bits.rxinfo || np->rxopt.bits.rxoinfo)
1307                         np->mcast_oif = tcp_v6_iif(opt_skb);
1308                 if (np->rxopt.bits.rxhlim || np->rxopt.bits.rxohlim)
1309                         np->mcast_hops = ipv6_hdr(opt_skb)->hop_limit;
1310                 if (np->rxopt.bits.rxflow || np->rxopt.bits.rxtclass)
1311                         np->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(opt_skb));
1312                 if (np->repflow)
1313                         np->flow_label = ip6_flowlabel(ipv6_hdr(opt_skb));
1314                 if (ipv6_opt_accepted(sk, opt_skb, &TCP_SKB_CB(opt_skb)->header.h6)) {
1315                         skb_set_owner_r(opt_skb, sk);
1316                         opt_skb = xchg(&np->pktoptions, opt_skb);
1317                 } else {
1318                         __kfree_skb(opt_skb);
1319                         opt_skb = xchg(&np->pktoptions, NULL);
1320                 }
1321         }
1322
1323         kfree_skb(opt_skb);
1324         return 0;
1325 }
1326
1327 static void tcp_v6_fill_cb(struct sk_buff *skb, const struct ipv6hdr *hdr,
1328                            const struct tcphdr *th)
1329 {
1330         /* This is tricky: we move IP6CB at its correct location into
1331          * TCP_SKB_CB(). It must be done after xfrm6_policy_check(), because
1332          * _decode_session6() uses IP6CB().
1333          * barrier() makes sure compiler won't play aliasing games.
1334          */
1335         memmove(&TCP_SKB_CB(skb)->header.h6, IP6CB(skb),
1336                 sizeof(struct inet6_skb_parm));
1337         barrier();
1338
1339         TCP_SKB_CB(skb)->seq = ntohl(th->seq);
1340         TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
1341                                     skb->len - th->doff*4);
1342         TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
1343         TCP_SKB_CB(skb)->tcp_flags = tcp_flag_byte(th);
1344         TCP_SKB_CB(skb)->tcp_tw_isn = 0;
1345         TCP_SKB_CB(skb)->ip_dsfield = ipv6_get_dsfield(hdr);
1346         TCP_SKB_CB(skb)->sacked = 0;
1347 }
1348
1349 static void tcp_v6_restore_cb(struct sk_buff *skb)
1350 {
1351         /* We need to move header back to the beginning if xfrm6_policy_check()
1352          * and tcp_v6_fill_cb() are going to be called again.
1353          */
1354         memmove(IP6CB(skb), &TCP_SKB_CB(skb)->header.h6,
1355                 sizeof(struct inet6_skb_parm));
1356 }
1357
1358 static int tcp_v6_rcv(struct sk_buff *skb)
1359 {
1360         const struct tcphdr *th;
1361         const struct ipv6hdr *hdr;
1362         bool refcounted;
1363         struct sock *sk;
1364         int ret;
1365         struct net *net = dev_net(skb->dev);
1366
1367         if (skb->pkt_type != PACKET_HOST)
1368                 goto discard_it;
1369
1370         /*
1371          *      Count it even if it's bad.
1372          */
1373         __TCP_INC_STATS(net, TCP_MIB_INSEGS);
1374
1375         if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
1376                 goto discard_it;
1377
1378         th = (const struct tcphdr *)skb->data;
1379
1380         if (unlikely(th->doff < sizeof(struct tcphdr)/4))
1381                 goto bad_packet;
1382         if (!pskb_may_pull(skb, th->doff*4))
1383                 goto discard_it;
1384
1385         if (skb_checksum_init(skb, IPPROTO_TCP, ip6_compute_pseudo))
1386                 goto csum_error;
1387
1388         th = (const struct tcphdr *)skb->data;
1389         hdr = ipv6_hdr(skb);
1390
1391 lookup:
1392         sk = __inet6_lookup_skb(&tcp_hashinfo, skb, __tcp_hdrlen(th),
1393                                 th->source, th->dest, inet6_iif(skb),
1394                                 &refcounted);
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 (sk->sk_state == TCP_NEW_SYN_RECV) {
1403                 struct request_sock *req = inet_reqsk(sk);
1404                 struct sock *nsk;
1405
1406                 sk = req->rsk_listener;
1407                 tcp_v6_fill_cb(skb, hdr, th);
1408                 if (tcp_v6_inbound_md5_hash(sk, skb)) {
1409                         reqsk_put(req);
1410                         goto discard_it;
1411                 }
1412                 if (unlikely(sk->sk_state != TCP_LISTEN)) {
1413                         inet_csk_reqsk_queue_drop_and_put(sk, req);
1414                         goto lookup;
1415                 }
1416                 sock_hold(sk);
1417                 refcounted = true;
1418                 nsk = tcp_check_req(sk, skb, req, false);
1419                 if (!nsk) {
1420                         reqsk_put(req);
1421                         goto discard_and_relse;
1422                 }
1423                 if (nsk == sk) {
1424                         reqsk_put(req);
1425                         tcp_v6_restore_cb(skb);
1426                 } else if (tcp_child_process(sk, nsk, skb)) {
1427                         tcp_v6_send_reset(nsk, skb);
1428                         goto discard_and_relse;
1429                 } else {
1430                         sock_put(sk);
1431                         return 0;
1432                 }
1433         }
1434         if (hdr->hop_limit < inet6_sk(sk)->min_hopcount) {
1435                 __NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP);
1436                 goto discard_and_relse;
1437         }
1438
1439         if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb))
1440                 goto discard_and_relse;
1441
1442         tcp_v6_fill_cb(skb, hdr, th);
1443
1444         if (tcp_v6_inbound_md5_hash(sk, skb))
1445                 goto discard_and_relse;
1446
1447         if (sk_filter(sk, skb))
1448                 goto discard_and_relse;
1449
1450         skb->dev = NULL;
1451
1452         if (sk->sk_state == TCP_LISTEN) {
1453                 ret = tcp_v6_do_rcv(sk, skb);
1454                 goto put_and_return;
1455         }
1456
1457         sk_incoming_cpu_update(sk);
1458
1459         bh_lock_sock_nested(sk);
1460         tcp_segs_in(tcp_sk(sk), skb);
1461         ret = 0;
1462         if (!sock_owned_by_user(sk)) {
1463                 if (!tcp_prequeue(sk, skb))
1464                         ret = tcp_v6_do_rcv(sk, skb);
1465         } else if (unlikely(sk_add_backlog(sk, skb,
1466                                            sk->sk_rcvbuf + sk->sk_sndbuf))) {
1467                 bh_unlock_sock(sk);
1468                 __NET_INC_STATS(net, LINUX_MIB_TCPBACKLOGDROP);
1469                 goto discard_and_relse;
1470         }
1471         bh_unlock_sock(sk);
1472
1473 put_and_return:
1474         if (refcounted)
1475                 sock_put(sk);
1476         return ret ? -1 : 0;
1477
1478 no_tcp_socket:
1479         if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb))
1480                 goto discard_it;
1481
1482         tcp_v6_fill_cb(skb, hdr, th);
1483
1484         if (tcp_checksum_complete(skb)) {
1485 csum_error:
1486                 __TCP_INC_STATS(net, TCP_MIB_CSUMERRORS);
1487 bad_packet:
1488                 __TCP_INC_STATS(net, TCP_MIB_INERRS);
1489         } else {
1490                 tcp_v6_send_reset(NULL, skb);
1491         }
1492
1493 discard_it:
1494         kfree_skb(skb);
1495         return 0;
1496
1497 discard_and_relse:
1498         sk_drops_add(sk, skb);
1499         if (refcounted)
1500                 sock_put(sk);
1501         goto discard_it;
1502
1503 do_time_wait:
1504         if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
1505                 inet_twsk_put(inet_twsk(sk));
1506                 goto discard_it;
1507         }
1508
1509         tcp_v6_fill_cb(skb, hdr, th);
1510
1511         if (tcp_checksum_complete(skb)) {
1512                 inet_twsk_put(inet_twsk(sk));
1513                 goto csum_error;
1514         }
1515
1516         switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) {
1517         case TCP_TW_SYN:
1518         {
1519                 struct sock *sk2;
1520
1521                 sk2 = inet6_lookup_listener(dev_net(skb->dev), &tcp_hashinfo,
1522                                             skb, __tcp_hdrlen(th),
1523                                             &ipv6_hdr(skb)->saddr, th->source,
1524                                             &ipv6_hdr(skb)->daddr,
1525                                             ntohs(th->dest), tcp_v6_iif(skb));
1526                 if (sk2) {
1527                         struct inet_timewait_sock *tw = inet_twsk(sk);
1528                         inet_twsk_deschedule_put(tw);
1529                         sk = sk2;
1530                         tcp_v6_restore_cb(skb);
1531                         refcounted = false;
1532                         goto process;
1533                 }
1534                 /* Fall through to ACK */
1535         }
1536         case TCP_TW_ACK:
1537                 tcp_v6_timewait_ack(sk, skb);
1538                 break;
1539         case TCP_TW_RST:
1540                 tcp_v6_restore_cb(skb);
1541                 tcp_v6_send_reset(sk, skb);
1542                 inet_twsk_deschedule_put(inet_twsk(sk));
1543                 goto discard_it;
1544         case TCP_TW_SUCCESS:
1545                 ;
1546         }
1547         goto discard_it;
1548 }
1549
1550 static void tcp_v6_early_demux(struct sk_buff *skb)
1551 {
1552         const struct ipv6hdr *hdr;
1553         const struct tcphdr *th;
1554         struct sock *sk;
1555
1556         if (skb->pkt_type != PACKET_HOST)
1557                 return;
1558
1559         if (!pskb_may_pull(skb, skb_transport_offset(skb) + sizeof(struct tcphdr)))
1560                 return;
1561
1562         hdr = ipv6_hdr(skb);
1563         th = tcp_hdr(skb);
1564
1565         if (th->doff < sizeof(struct tcphdr) / 4)
1566                 return;
1567
1568         /* Note : We use inet6_iif() here, not tcp_v6_iif() */
1569         sk = __inet6_lookup_established(dev_net(skb->dev), &tcp_hashinfo,
1570                                         &hdr->saddr, th->source,
1571                                         &hdr->daddr, ntohs(th->dest),
1572                                         inet6_iif(skb));
1573         if (sk) {
1574                 skb->sk = sk;
1575                 skb->destructor = sock_edemux;
1576                 if (sk_fullsock(sk)) {
1577                         struct dst_entry *dst = READ_ONCE(sk->sk_rx_dst);
1578
1579                         if (dst)
1580                                 dst = dst_check(dst, inet6_sk(sk)->rx_dst_cookie);
1581                         if (dst &&
1582                             inet_sk(sk)->rx_dst_ifindex == skb->skb_iif)
1583                                 skb_dst_set_noref(skb, dst);
1584                 }
1585         }
1586 }
1587
1588 static struct timewait_sock_ops tcp6_timewait_sock_ops = {
1589         .twsk_obj_size  = sizeof(struct tcp6_timewait_sock),
1590         .twsk_unique    = tcp_twsk_unique,
1591         .twsk_destructor = tcp_twsk_destructor,
1592 };
1593
1594 static const struct inet_connection_sock_af_ops ipv6_specific = {
1595         .queue_xmit        = inet6_csk_xmit,
1596         .send_check        = tcp_v6_send_check,
1597         .rebuild_header    = inet6_sk_rebuild_header,
1598         .sk_rx_dst_set     = inet6_sk_rx_dst_set,
1599         .conn_request      = tcp_v6_conn_request,
1600         .syn_recv_sock     = tcp_v6_syn_recv_sock,
1601         .net_header_len    = sizeof(struct ipv6hdr),
1602         .net_frag_header_len = sizeof(struct frag_hdr),
1603         .setsockopt        = ipv6_setsockopt,
1604         .getsockopt        = ipv6_getsockopt,
1605         .addr2sockaddr     = inet6_csk_addr2sockaddr,
1606         .sockaddr_len      = sizeof(struct sockaddr_in6),
1607         .bind_conflict     = inet6_csk_bind_conflict,
1608 #ifdef CONFIG_COMPAT
1609         .compat_setsockopt = compat_ipv6_setsockopt,
1610         .compat_getsockopt = compat_ipv6_getsockopt,
1611 #endif
1612         .mtu_reduced       = tcp_v6_mtu_reduced,
1613 };
1614
1615 #ifdef CONFIG_TCP_MD5SIG
1616 static const struct tcp_sock_af_ops tcp_sock_ipv6_specific = {
1617         .md5_lookup     =       tcp_v6_md5_lookup,
1618         .calc_md5_hash  =       tcp_v6_md5_hash_skb,
1619         .md5_parse      =       tcp_v6_parse_md5_keys,
1620 };
1621 #endif
1622
1623 /*
1624  *      TCP over IPv4 via INET6 API
1625  */
1626 static const struct inet_connection_sock_af_ops ipv6_mapped = {
1627         .queue_xmit        = ip_queue_xmit,
1628         .send_check        = tcp_v4_send_check,
1629         .rebuild_header    = inet_sk_rebuild_header,
1630         .sk_rx_dst_set     = inet_sk_rx_dst_set,
1631         .conn_request      = tcp_v6_conn_request,
1632         .syn_recv_sock     = tcp_v6_syn_recv_sock,
1633         .net_header_len    = sizeof(struct iphdr),
1634         .setsockopt        = ipv6_setsockopt,
1635         .getsockopt        = ipv6_getsockopt,
1636         .addr2sockaddr     = inet6_csk_addr2sockaddr,
1637         .sockaddr_len      = sizeof(struct sockaddr_in6),
1638         .bind_conflict     = inet6_csk_bind_conflict,
1639 #ifdef CONFIG_COMPAT
1640         .compat_setsockopt = compat_ipv6_setsockopt,
1641         .compat_getsockopt = compat_ipv6_getsockopt,
1642 #endif
1643         .mtu_reduced       = tcp_v4_mtu_reduced,
1644 };
1645
1646 #ifdef CONFIG_TCP_MD5SIG
1647 static const struct tcp_sock_af_ops tcp_sock_ipv6_mapped_specific = {
1648         .md5_lookup     =       tcp_v4_md5_lookup,
1649         .calc_md5_hash  =       tcp_v4_md5_hash_skb,
1650         .md5_parse      =       tcp_v6_parse_md5_keys,
1651 };
1652 #endif
1653
1654 /* NOTE: A lot of things set to zero explicitly by call to
1655  *       sk_alloc() so need not be done here.
1656  */
1657 static int tcp_v6_init_sock(struct sock *sk)
1658 {
1659         struct inet_connection_sock *icsk = inet_csk(sk);
1660
1661         tcp_init_sock(sk);
1662
1663         icsk->icsk_af_ops = &ipv6_specific;
1664
1665 #ifdef CONFIG_TCP_MD5SIG
1666         tcp_sk(sk)->af_specific = &tcp_sock_ipv6_specific;
1667 #endif
1668
1669         return 0;
1670 }
1671
1672 static void tcp_v6_destroy_sock(struct sock *sk)
1673 {
1674         tcp_v4_destroy_sock(sk);
1675         inet6_destroy_sock(sk);
1676 }
1677
1678 #ifdef CONFIG_PROC_FS
1679 /* Proc filesystem TCPv6 sock list dumping. */
1680 static void get_openreq6(struct seq_file *seq,
1681                          const struct request_sock *req, int i)
1682 {
1683         long ttd = req->rsk_timer.expires - jiffies;
1684         const struct in6_addr *src = &inet_rsk(req)->ir_v6_loc_addr;
1685         const struct in6_addr *dest = &inet_rsk(req)->ir_v6_rmt_addr;
1686
1687         if (ttd < 0)
1688                 ttd = 0;
1689
1690         seq_printf(seq,
1691                    "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
1692                    "%02X %08X:%08X %02X:%08lX %08X %5u %8d %d %d %pK\n",
1693                    i,
1694                    src->s6_addr32[0], src->s6_addr32[1],
1695                    src->s6_addr32[2], src->s6_addr32[3],
1696                    inet_rsk(req)->ir_num,
1697                    dest->s6_addr32[0], dest->s6_addr32[1],
1698                    dest->s6_addr32[2], dest->s6_addr32[3],
1699                    ntohs(inet_rsk(req)->ir_rmt_port),
1700                    TCP_SYN_RECV,
1701                    0, 0, /* could print option size, but that is af dependent. */
1702                    1,   /* timers active (only the expire timer) */
1703                    jiffies_to_clock_t(ttd),
1704                    req->num_timeout,
1705                    from_kuid_munged(seq_user_ns(seq),
1706                                     sock_i_uid(req->rsk_listener)),
1707                    0,  /* non standard timer */
1708                    0, /* open_requests have no inode */
1709                    0, req);
1710 }
1711
1712 static void get_tcp6_sock(struct seq_file *seq, struct sock *sp, int i)
1713 {
1714         const struct in6_addr *dest, *src;
1715         __u16 destp, srcp;
1716         int timer_active;
1717         unsigned long timer_expires;
1718         const struct inet_sock *inet = inet_sk(sp);
1719         const struct tcp_sock *tp = tcp_sk(sp);
1720         const struct inet_connection_sock *icsk = inet_csk(sp);
1721         const struct fastopen_queue *fastopenq = &icsk->icsk_accept_queue.fastopenq;
1722         int rx_queue;
1723         int state;
1724
1725         dest  = &sp->sk_v6_daddr;
1726         src   = &sp->sk_v6_rcv_saddr;
1727         destp = ntohs(inet->inet_dport);
1728         srcp  = ntohs(inet->inet_sport);
1729
1730         if (icsk->icsk_pending == ICSK_TIME_RETRANS) {
1731                 timer_active    = 1;
1732                 timer_expires   = icsk->icsk_timeout;
1733         } else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
1734                 timer_active    = 4;
1735                 timer_expires   = icsk->icsk_timeout;
1736         } else if (timer_pending(&sp->sk_timer)) {
1737                 timer_active    = 2;
1738                 timer_expires   = sp->sk_timer.expires;
1739         } else {
1740                 timer_active    = 0;
1741                 timer_expires = jiffies;
1742         }
1743
1744         state = sk_state_load(sp);
1745         if (state == TCP_LISTEN)
1746                 rx_queue = sp->sk_ack_backlog;
1747         else
1748                 /* Because we don't lock the socket,
1749                  * we might find a transient negative value.
1750                  */
1751                 rx_queue = max_t(int, tp->rcv_nxt - tp->copied_seq, 0);
1752
1753         seq_printf(seq,
1754                    "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
1755                    "%02X %08X:%08X %02X:%08lX %08X %5u %8d %lu %d %pK %lu %lu %u %u %d\n",
1756                    i,
1757                    src->s6_addr32[0], src->s6_addr32[1],
1758                    src->s6_addr32[2], src->s6_addr32[3], srcp,
1759                    dest->s6_addr32[0], dest->s6_addr32[1],
1760                    dest->s6_addr32[2], dest->s6_addr32[3], destp,
1761                    state,
1762                    tp->write_seq - tp->snd_una,
1763                    rx_queue,
1764                    timer_active,
1765                    jiffies_delta_to_clock_t(timer_expires - jiffies),
1766                    icsk->icsk_retransmits,
1767                    from_kuid_munged(seq_user_ns(seq), sock_i_uid(sp)),
1768                    icsk->icsk_probes_out,
1769                    sock_i_ino(sp),
1770                    atomic_read(&sp->sk_refcnt), sp,
1771                    jiffies_to_clock_t(icsk->icsk_rto),
1772                    jiffies_to_clock_t(icsk->icsk_ack.ato),
1773                    (icsk->icsk_ack.quick << 1) | icsk->icsk_ack.pingpong,
1774                    tp->snd_cwnd,
1775                    state == TCP_LISTEN ?
1776                         fastopenq->max_qlen :
1777                         (tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh)
1778                    );
1779 }
1780
1781 static void get_timewait6_sock(struct seq_file *seq,
1782                                struct inet_timewait_sock *tw, int i)
1783 {
1784         long delta = tw->tw_timer.expires - jiffies;
1785         const struct in6_addr *dest, *src;
1786         __u16 destp, srcp;
1787
1788         dest = &tw->tw_v6_daddr;
1789         src  = &tw->tw_v6_rcv_saddr;
1790         destp = ntohs(tw->tw_dport);
1791         srcp  = ntohs(tw->tw_sport);
1792
1793         seq_printf(seq,
1794                    "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
1795                    "%02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK\n",
1796                    i,
1797                    src->s6_addr32[0], src->s6_addr32[1],
1798                    src->s6_addr32[2], src->s6_addr32[3], srcp,
1799                    dest->s6_addr32[0], dest->s6_addr32[1],
1800                    dest->s6_addr32[2], dest->s6_addr32[3], destp,
1801                    tw->tw_substate, 0, 0,
1802                    3, jiffies_delta_to_clock_t(delta), 0, 0, 0, 0,
1803                    atomic_read(&tw->tw_refcnt), tw);
1804 }
1805
1806 static int tcp6_seq_show(struct seq_file *seq, void *v)
1807 {
1808         struct tcp_iter_state *st;
1809         struct sock *sk = v;
1810
1811         if (v == SEQ_START_TOKEN) {
1812                 seq_puts(seq,
1813                          "  sl  "
1814                          "local_address                         "
1815                          "remote_address                        "
1816                          "st tx_queue rx_queue tr tm->when retrnsmt"
1817                          "   uid  timeout inode\n");
1818                 goto out;
1819         }
1820         st = seq->private;
1821
1822         if (sk->sk_state == TCP_TIME_WAIT)
1823                 get_timewait6_sock(seq, v, st->num);
1824         else if (sk->sk_state == TCP_NEW_SYN_RECV)
1825                 get_openreq6(seq, v, st->num);
1826         else
1827                 get_tcp6_sock(seq, v, st->num);
1828 out:
1829         return 0;
1830 }
1831
1832 static const struct file_operations tcp6_afinfo_seq_fops = {
1833         .owner   = THIS_MODULE,
1834         .open    = tcp_seq_open,
1835         .read    = seq_read,
1836         .llseek  = seq_lseek,
1837         .release = seq_release_net
1838 };
1839
1840 static struct tcp_seq_afinfo tcp6_seq_afinfo = {
1841         .name           = "tcp6",
1842         .family         = AF_INET6,
1843         .seq_fops       = &tcp6_afinfo_seq_fops,
1844         .seq_ops        = {
1845                 .show           = tcp6_seq_show,
1846         },
1847 };
1848
1849 int __net_init tcp6_proc_init(struct net *net)
1850 {
1851         return tcp_proc_register(net, &tcp6_seq_afinfo);
1852 }
1853
1854 void tcp6_proc_exit(struct net *net)
1855 {
1856         tcp_proc_unregister(net, &tcp6_seq_afinfo);
1857 }
1858 #endif
1859
1860 static void tcp_v6_clear_sk(struct sock *sk, int size)
1861 {
1862         struct inet_sock *inet = inet_sk(sk);
1863
1864         /* we do not want to clear pinet6 field, because of RCU lookups */
1865         sk_prot_clear_nulls(sk, offsetof(struct inet_sock, pinet6));
1866
1867         size -= offsetof(struct inet_sock, pinet6) + sizeof(inet->pinet6);
1868         memset(&inet->pinet6 + 1, 0, size);
1869 }
1870
1871 struct proto tcpv6_prot = {
1872         .name                   = "TCPv6",
1873         .owner                  = THIS_MODULE,
1874         .close                  = tcp_close,
1875         .connect                = tcp_v6_connect,
1876         .disconnect             = tcp_disconnect,
1877         .accept                 = inet_csk_accept,
1878         .ioctl                  = tcp_ioctl,
1879         .init                   = tcp_v6_init_sock,
1880         .destroy                = tcp_v6_destroy_sock,
1881         .shutdown               = tcp_shutdown,
1882         .setsockopt             = tcp_setsockopt,
1883         .getsockopt             = tcp_getsockopt,
1884         .recvmsg                = tcp_recvmsg,
1885         .sendmsg                = tcp_sendmsg,
1886         .sendpage               = tcp_sendpage,
1887         .backlog_rcv            = tcp_v6_do_rcv,
1888         .release_cb             = tcp_release_cb,
1889         .hash                   = inet6_hash,
1890         .unhash                 = inet_unhash,
1891         .get_port               = inet_csk_get_port,
1892         .enter_memory_pressure  = tcp_enter_memory_pressure,
1893         .stream_memory_free     = tcp_stream_memory_free,
1894         .sockets_allocated      = &tcp_sockets_allocated,
1895         .memory_allocated       = &tcp_memory_allocated,
1896         .memory_pressure        = &tcp_memory_pressure,
1897         .orphan_count           = &tcp_orphan_count,
1898         .sysctl_mem             = sysctl_tcp_mem,
1899         .sysctl_wmem            = sysctl_tcp_wmem,
1900         .sysctl_rmem            = sysctl_tcp_rmem,
1901         .max_header             = MAX_TCP_HEADER,
1902         .obj_size               = sizeof(struct tcp6_sock),
1903         .slab_flags             = SLAB_DESTROY_BY_RCU,
1904         .twsk_prot              = &tcp6_timewait_sock_ops,
1905         .rsk_prot               = &tcp6_request_sock_ops,
1906         .h.hashinfo             = &tcp_hashinfo,
1907         .no_autobind            = true,
1908 #ifdef CONFIG_COMPAT
1909         .compat_setsockopt      = compat_tcp_setsockopt,
1910         .compat_getsockopt      = compat_tcp_getsockopt,
1911 #endif
1912         .clear_sk               = tcp_v6_clear_sk,
1913         .diag_destroy           = tcp_abort,
1914 };
1915
1916 static const struct inet6_protocol tcpv6_protocol = {
1917         .early_demux    =       tcp_v6_early_demux,
1918         .handler        =       tcp_v6_rcv,
1919         .err_handler    =       tcp_v6_err,
1920         .flags          =       INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
1921 };
1922
1923 static struct inet_protosw tcpv6_protosw = {
1924         .type           =       SOCK_STREAM,
1925         .protocol       =       IPPROTO_TCP,
1926         .prot           =       &tcpv6_prot,
1927         .ops            =       &inet6_stream_ops,
1928         .flags          =       INET_PROTOSW_PERMANENT |
1929                                 INET_PROTOSW_ICSK,
1930 };
1931
1932 static int __net_init tcpv6_net_init(struct net *net)
1933 {
1934         return inet_ctl_sock_create(&net->ipv6.tcp_sk, PF_INET6,
1935                                     SOCK_RAW, IPPROTO_TCP, net);
1936 }
1937
1938 static void __net_exit tcpv6_net_exit(struct net *net)
1939 {
1940         inet_ctl_sock_destroy(net->ipv6.tcp_sk);
1941 }
1942
1943 static void __net_exit tcpv6_net_exit_batch(struct list_head *net_exit_list)
1944 {
1945         inet_twsk_purge(&tcp_hashinfo, &tcp_death_row, AF_INET6);
1946 }
1947
1948 static struct pernet_operations tcpv6_net_ops = {
1949         .init       = tcpv6_net_init,
1950         .exit       = tcpv6_net_exit,
1951         .exit_batch = tcpv6_net_exit_batch,
1952 };
1953
1954 int __init tcpv6_init(void)
1955 {
1956         int ret;
1957
1958         ret = inet6_add_protocol(&tcpv6_protocol, IPPROTO_TCP);
1959         if (ret)
1960                 goto out;
1961
1962         /* register inet6 protocol */
1963         ret = inet6_register_protosw(&tcpv6_protosw);
1964         if (ret)
1965                 goto out_tcpv6_protocol;
1966
1967         ret = register_pernet_subsys(&tcpv6_net_ops);
1968         if (ret)
1969                 goto out_tcpv6_protosw;
1970 out:
1971         return ret;
1972
1973 out_tcpv6_protosw:
1974         inet6_unregister_protosw(&tcpv6_protosw);
1975 out_tcpv6_protocol:
1976         inet6_del_protocol(&tcpv6_protocol, IPPROTO_TCP);
1977         goto out;
1978 }
1979
1980 void tcpv6_exit(void)
1981 {
1982         unregister_pernet_subsys(&tcpv6_net_ops);
1983         inet6_unregister_protosw(&tcpv6_protosw);
1984         inet6_del_protocol(&tcpv6_protocol, IPPROTO_TCP);
1985 }