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_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                               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 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, synack_type);
 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                 fl6.flowi6_oif = oif;
 815         fl6.flowi6_mark = IP6_REPLY_MARK(net, skb->mark);
 816         fl6.fl6_dport = t1->dest;
 817         fl6.fl6_sport = t1->source;
 818         security_skb_classify_flow(skb, flowi6_to_flowi(&fl6));
 819
 820         /* Pass a socket to ip6_dst_lookup either it is for RST
 821          * Underlying function will use this to retrieve the network
 822          * namespace
 823          */
 824         dst = ip6_dst_lookup_flow(ctl_sk, &fl6, NULL);
 825         if (!IS_ERR(dst)) {
 826                 skb_dst_set(buff, dst);
 827                 ip6_xmit(ctl_sk, buff, &fl6, NULL, tclass);
 828                 TCP_INC_STATS_BH(net, TCP_MIB_OUTSEGS);
 829                 if (rst)
 830                         TCP_INC_STATS_BH(net, TCP_MIB_OUTRSTS);
 831                 return;
 832         }
 833
 834         kfree_skb(buff);
 835 }
 836
 837 static void tcp_v6_send_reset(const struct sock *sk, struct sk_buff *skb)
 838 {
 839         const struct tcphdr *th = tcp_hdr(skb);
 840         u32 seq = 0, ack_seq = 0;
 841         struct tcp_md5sig_key *key = NULL;
 842 #ifdef CONFIG_TCP_MD5SIG
 843         const __u8 *hash_location = NULL;
 844         struct ipv6hdr *ipv6h = ipv6_hdr(skb);
 845         unsigned char newhash[16];
 846         int genhash;
 847         struct sock *sk1 = NULL;
 848 #endif
 849         int oif;
 850
 851         if (th->rst)
 852                 return;
 853
 854         /* If sk not NULL, it means we did a successful lookup and incoming
 855          * route had to be correct. prequeue might have dropped our dst.
 856          */
 857         if (!sk && !ipv6_unicast_destination(skb))
 858                 return;
 859
 860 #ifdef CONFIG_TCP_MD5SIG
 861         rcu_read_lock();
 862         hash_location = tcp_parse_md5sig_option(th);
 863         if (sk && sk_fullsock(sk)) {
 864                 key = tcp_v6_md5_do_lookup(sk, &ipv6h->saddr);
 865         } else if (hash_location) {
 866                 /*
 867                  * active side is lost. Try to find listening socket through
 868                  * source port, and then find md5 key through listening socket.
 869                  * we are not loose security here:
 870                  * Incoming packet is checked with md5 hash with finding key,
 871                  * no RST generated if md5 hash doesn't match.
 872                  */
 873                 sk1 = inet6_lookup_listener(dev_net(skb_dst(skb)->dev),
 874                                            &tcp_hashinfo, NULL, 0,
 875                                            &ipv6h->saddr,
 876                                            th->source, &ipv6h->daddr,
 877                                            ntohs(th->source), tcp_v6_iif(skb));
 878                 if (!sk1)
 879                         goto out;
 880
 881                 key = tcp_v6_md5_do_lookup(sk1, &ipv6h->saddr);
 882                 if (!key)
 883                         goto out;
 884
 885                 genhash = tcp_v6_md5_hash_skb(newhash, key, NULL, skb);
 886                 if (genhash || memcmp(hash_location, newhash, 16) != 0)
 887                         goto out;
 888         }
 889 #endif
 890
 891         if (th->ack)
 892                 seq = ntohl(th->ack_seq);
 893         else
 894                 ack_seq = ntohl(th->seq) + th->syn + th->fin + skb->len -
 895                           (th->doff << 2);
 896
 897         oif = sk ? sk->sk_bound_dev_if : 0;
 898         tcp_v6_send_response(sk, skb, seq, ack_seq, 0, 0, 0, oif, key, 1, 0, 0);
 899
 900 #ifdef CONFIG_TCP_MD5SIG
 901 out:
 902         rcu_read_unlock();
 903 #endif
 904 }
 905
 906 static void tcp_v6_send_ack(const struct sock *sk, struct sk_buff *skb, u32 seq,
 907                             u32 ack, u32 win, u32 tsval, u32 tsecr, int oif,
 908                             struct tcp_md5sig_key *key, u8 tclass,
 909                             u32 label)
 910 {
 911         tcp_v6_send_response(sk, skb, seq, ack, win, tsval, tsecr, oif, key, 0,
 912                              tclass, label);
 913 }
 914
 915 static void tcp_v6_timewait_ack(struct sock *sk, struct sk_buff *skb)
 916 {
 917         struct inet_timewait_sock *tw = inet_twsk(sk);
 918         struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
 919
 920         tcp_v6_send_ack(sk, skb, tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
 921                         tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
 922                         tcp_time_stamp + tcptw->tw_ts_offset,
 923                         tcptw->tw_ts_recent, tw->tw_bound_dev_if, tcp_twsk_md5_key(tcptw),
 924                         tw->tw_tclass, cpu_to_be32(tw->tw_flowlabel));
 925
 926         inet_twsk_put(tw);
 927 }
 928
 929 static void tcp_v6_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb,
 930                                   struct request_sock *req)
 931 {
 932         /* sk->sk_state == TCP_LISTEN -> for regular TCP_SYN_RECV
 933          * sk->sk_state == TCP_SYN_RECV -> for Fast Open.
 934          */
 935         tcp_v6_send_ack(sk, skb, (sk->sk_state == TCP_LISTEN) ?
 936                         tcp_rsk(req)->snt_isn + 1 : tcp_sk(sk)->snd_nxt,
 937                         tcp_rsk(req)->rcv_nxt, req->rsk_rcv_wnd,
 938                         tcp_time_stamp, req->ts_recent, sk->sk_bound_dev_if,
 939                         tcp_v6_md5_do_lookup(sk, &ipv6_hdr(skb)->daddr),
 940                         0, 0);
 941 }
 942
 943
 944 static struct sock *tcp_v6_cookie_check(struct sock *sk, struct sk_buff *skb)
 945 {
 946 #ifdef CONFIG_SYN_COOKIES
 947         const struct tcphdr *th = tcp_hdr(skb);
 948
 949         if (!th->syn)
 950                 sk = cookie_v6_check(sk, skb);
 951 #endif
 952         return sk;
 953 }
 954
 955 static int tcp_v6_conn_request(struct sock *sk, struct sk_buff *skb)
 956 {
 957         if (skb->protocol == htons(ETH_P_IP))
 958                 return tcp_v4_conn_request(sk, skb);
 959
 960         if (!ipv6_unicast_destination(skb))
 961                 goto drop;
 962
 963         return tcp_conn_request(&tcp6_request_sock_ops,
 964                                 &tcp_request_sock_ipv6_ops, sk, skb);
 965
 966 drop:
 967         tcp_listendrop(sk);
 968         return 0; /* don't send reset */
 969 }
 970
 971 static struct sock *tcp_v6_syn_recv_sock(const struct sock *sk, struct sk_buff *skb,
 972                                          struct request_sock *req,
 973                                          struct dst_entry *dst,
 974                                          struct request_sock *req_unhash,
 975                                          bool *own_req)
 976 {
 977         struct inet_request_sock *ireq;
 978         struct ipv6_pinfo *newnp;
 979         const struct ipv6_pinfo *np = inet6_sk(sk);
 980         struct ipv6_txoptions *opt;
 981         struct tcp6_sock *newtcp6sk;
 982         struct inet_sock *newinet;
 983         struct tcp_sock *newtp;
 984         struct sock *newsk;
 985 #ifdef CONFIG_TCP_MD5SIG
 986         struct tcp_md5sig_key *key;
 987 #endif
 988         struct flowi6 fl6;
 989
 990         if (skb->protocol == htons(ETH_P_IP)) {
 991                 /*
 992                  *      v6 mapped
 993                  */
 994
 995                 newsk = tcp_v4_syn_recv_sock(sk, skb, req, dst,
 996                                              req_unhash, own_req);
 997
 998                 if (!newsk)
 999                         return NULL;
1000
1001                 newtcp6sk = (struct tcp6_sock *)newsk;
1002                 inet_sk(newsk)->pinet6 = &newtcp6sk->inet6;
1003
1004                 newinet = inet_sk(newsk);
1005                 newnp = inet6_sk(newsk);
1006                 newtp = tcp_sk(newsk);
1007
1008                 memcpy(newnp, np, sizeof(struct ipv6_pinfo));
1009
1010                 newnp->saddr = newsk->sk_v6_rcv_saddr;
1011
1012                 inet_csk(newsk)->icsk_af_ops = &ipv6_mapped;
1013                 newsk->sk_backlog_rcv = tcp_v4_do_rcv;
1014 #ifdef CONFIG_TCP_MD5SIG
1015                 newtp->af_specific = &tcp_sock_ipv6_mapped_specific;
1016 #endif
1017
1018                 newnp->ipv6_ac_list = NULL;
1019                 newnp->ipv6_fl_list = NULL;
1020                 newnp->pktoptions  = NULL;
1021                 newnp->opt         = NULL;
1022                 newnp->mcast_oif   = tcp_v6_iif(skb);
1023                 newnp->mcast_hops  = ipv6_hdr(skb)->hop_limit;
1024                 newnp->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(skb));
1025                 if (np->repflow)
1026                         newnp->flow_label = ip6_flowlabel(ipv6_hdr(skb));
1027
1028                 /*
1029                  * No need to charge this sock to the relevant IPv6 refcnt debug socks count
1030                  * here, tcp_create_openreq_child now does this for us, see the comment in
1031                  * that function for the gory details. -acme
1032                  */
1033
1034                 /* It is tricky place. Until this moment IPv4 tcp
1035                    worked with IPv6 icsk.icsk_af_ops.
1036                    Sync it now.
1037                  */
1038                 tcp_sync_mss(newsk, inet_csk(newsk)->icsk_pmtu_cookie);
1039
1040                 return newsk;
1041         }
1042
1043         ireq = inet_rsk(req);
1044
1045         if (sk_acceptq_is_full(sk))
1046                 goto out_overflow;
1047
1048         if (!dst) {
1049                 dst = inet6_csk_route_req(sk, &fl6, req, IPPROTO_TCP);
1050                 if (!dst)
1051                         goto out;
1052         }
1053
1054         newsk = tcp_create_openreq_child(sk, req, skb);
1055         if (!newsk)
1056                 goto out_nonewsk;
1057
1058         /*
1059          * No need to charge this sock to the relevant IPv6 refcnt debug socks
1060          * count here, tcp_create_openreq_child now does this for us, see the
1061          * comment in that function for the gory details. -acme
1062          */
1063
1064         newsk->sk_gso_type = SKB_GSO_TCPV6;
1065         ip6_dst_store(newsk, dst, NULL, NULL);
1066         inet6_sk_rx_dst_set(newsk, skb);
1067
1068         newtcp6sk = (struct tcp6_sock *)newsk;
1069         inet_sk(newsk)->pinet6 = &newtcp6sk->inet6;
1070
1071         newtp = tcp_sk(newsk);
1072         newinet = inet_sk(newsk);
1073         newnp = inet6_sk(newsk);
1074
1075         memcpy(newnp, np, sizeof(struct ipv6_pinfo));
1076
1077         newsk->sk_v6_daddr = ireq->ir_v6_rmt_addr;
1078         newnp->saddr = ireq->ir_v6_loc_addr;
1079         newsk->sk_v6_rcv_saddr = ireq->ir_v6_loc_addr;
1080         newsk->sk_bound_dev_if = ireq->ir_iif;
1081
1082         /* Now IPv6 options...
1083
1084            First: no IPv4 options.
1085          */
1086         newinet->inet_opt = NULL;
1087         newnp->ipv6_ac_list = NULL;
1088         newnp->ipv6_fl_list = NULL;
1089
1090         /* Clone RX bits */
1091         newnp->rxopt.all = np->rxopt.all;
1092
1093         newnp->pktoptions = NULL;
1094         newnp->opt        = NULL;
1095         newnp->mcast_oif  = tcp_v6_iif(skb);
1096         newnp->mcast_hops = ipv6_hdr(skb)->hop_limit;
1097         newnp->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(skb));
1098         if (np->repflow)
1099                 newnp->flow_label = ip6_flowlabel(ipv6_hdr(skb));
1100
1101         /* Clone native IPv6 options from listening socket (if any)
1102
1103            Yes, keeping reference count would be much more clever,
1104            but we make one more one thing there: reattach optmem
1105            to newsk.
1106          */
1107         opt = rcu_dereference(np->opt);
1108         if (opt) {
1109                 opt = ipv6_dup_options(newsk, opt);
1110                 RCU_INIT_POINTER(newnp->opt, opt);
1111         }
1112         inet_csk(newsk)->icsk_ext_hdr_len = 0;
1113         if (opt)
1114                 inet_csk(newsk)->icsk_ext_hdr_len = opt->opt_nflen +
1115                                                     opt->opt_flen;
1116
1117         tcp_ca_openreq_child(newsk, dst);
1118
1119         tcp_sync_mss(newsk, dst_mtu(dst));
1120         newtp->advmss = dst_metric_advmss(dst);
1121         if (tcp_sk(sk)->rx_opt.user_mss &&
1122             tcp_sk(sk)->rx_opt.user_mss < newtp->advmss)
1123                 newtp->advmss = tcp_sk(sk)->rx_opt.user_mss;
1124
1125         tcp_initialize_rcv_mss(newsk);
1126
1127         newinet->inet_daddr = newinet->inet_saddr = LOOPBACK4_IPV6;
1128         newinet->inet_rcv_saddr = LOOPBACK4_IPV6;
1129
1130 #ifdef CONFIG_TCP_MD5SIG
1131         /* Copy over the MD5 key from the original socket */
1132         key = tcp_v6_md5_do_lookup(sk, &newsk->sk_v6_daddr);
1133         if (key) {
1134                 /* We're using one, so create a matching key
1135                  * on the newsk structure. If we fail to get
1136                  * memory, then we end up not copying the key
1137                  * across. Shucks.
1138                  */
1139                 tcp_md5_do_add(newsk, (union tcp_md5_addr *)&newsk->sk_v6_daddr,
1140                                AF_INET6, key->key, key->keylen,
1141                                sk_gfp_mask(sk, GFP_ATOMIC));
1142         }
1143 #endif
1144
1145         if (__inet_inherit_port(sk, newsk) < 0) {
1146                 inet_csk_prepare_forced_close(newsk);
1147                 tcp_done(newsk);
1148                 goto out;
1149         }
1150         *own_req = inet_ehash_nolisten(newsk, req_to_sk(req_unhash));
1151         if (*own_req) {
1152                 tcp_move_syn(newtp, req);
1153
1154                 /* Clone pktoptions received with SYN, if we own the req */
1155                 if (ireq->pktopts) {
1156                         newnp->pktoptions = skb_clone(ireq->pktopts,
1157                                                       sk_gfp_mask(sk, GFP_ATOMIC));
1158                         consume_skb(ireq->pktopts);
1159                         ireq->pktopts = NULL;
1160                         if (newnp->pktoptions)
1161                                 skb_set_owner_r(newnp->pktoptions, newsk);
1162                 }
1163         }
1164
1165         return newsk;
1166
1167 out_overflow:
1168         NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
1169 out_nonewsk:
1170         dst_release(dst);
1171 out:
1172         tcp_listendrop(sk);
1173         return NULL;
1174 }
1175
1176 /* The socket must have it's spinlock held when we get
1177  * here, unless it is a TCP_LISTEN socket.
1178  *
1179  * We have a potential double-lock case here, so even when
1180  * doing backlog processing we use the BH locking scheme.
1181  * This is because we cannot sleep with the original spinlock
1182  * held.
1183  */
1184 static int tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb)
1185 {
1186         struct ipv6_pinfo *np = inet6_sk(sk);
1187         struct tcp_sock *tp;
1188         struct sk_buff *opt_skb = NULL;
1189
1190         /* Imagine: socket is IPv6. IPv4 packet arrives,
1191            goes to IPv4 receive handler and backlogged.
1192            From backlog it always goes here. Kerboom...
1193            Fortunately, tcp_rcv_established and rcv_established
1194            handle them correctly, but it is not case with
1195            tcp_v6_hnd_req and tcp_v6_send_reset().   --ANK
1196          */
1197
1198         if (skb->protocol == htons(ETH_P_IP))
1199                 return tcp_v4_do_rcv(sk, skb);
1200
1201         if (sk_filter(sk, skb))
1202                 goto discard;
1203
1204         /*
1205          *      socket locking is here for SMP purposes as backlog rcv
1206          *      is currently called with bh processing disabled.
1207          */
1208
1209         /* Do Stevens' IPV6_PKTOPTIONS.
1210
1211            Yes, guys, it is the only place in our code, where we
1212            may make it not affecting IPv4.
1213            The rest of code is protocol independent,
1214            and I do not like idea to uglify IPv4.
1215
1216            Actually, all the idea behind IPV6_PKTOPTIONS
1217            looks not very well thought. For now we latch
1218            options, received in the last packet, enqueued
1219            by tcp. Feel free to propose better solution.
1220                                                --ANK (980728)
1221          */
1222         if (np->rxopt.all)
1223                 opt_skb = skb_clone(skb, sk_gfp_mask(sk, GFP_ATOMIC));
1224
1225         if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
1226                 struct dst_entry *dst = sk->sk_rx_dst;
1227
1228                 sock_rps_save_rxhash(sk, skb);
1229                 sk_mark_napi_id(sk, skb);
1230                 if (dst) {
1231                         if (inet_sk(sk)->rx_dst_ifindex != skb->skb_iif ||
1232                             dst->ops->check(dst, np->rx_dst_cookie) == NULL) {
1233                                 dst_release(dst);
1234                                 sk->sk_rx_dst = NULL;
1235                         }
1236                 }
1237
1238                 tcp_rcv_established(sk, skb, tcp_hdr(skb), skb->len);
1239                 if (opt_skb)
1240                         goto ipv6_pktoptions;
1241                 return 0;
1242         }
1243
1244         if (tcp_checksum_complete(skb))
1245                 goto csum_err;
1246
1247         if (sk->sk_state == TCP_LISTEN) {
1248                 struct sock *nsk = tcp_v6_cookie_check(sk, skb);
1249
1250                 if (!nsk)
1251                         goto discard;
1252
1253                 if (nsk != sk) {
1254                         sock_rps_save_rxhash(nsk, skb);
1255                         sk_mark_napi_id(nsk, skb);
1256                         if (tcp_child_process(sk, nsk, skb))
1257                                 goto reset;
1258                         if (opt_skb)
1259                                 __kfree_skb(opt_skb);
1260                         return 0;
1261                 }
1262         } else
1263                 sock_rps_save_rxhash(sk, skb);
1264
1265         if (tcp_rcv_state_process(sk, skb))
1266                 goto reset;
1267         if (opt_skb)
1268                 goto ipv6_pktoptions;
1269         return 0;
1270
1271 reset:
1272         tcp_v6_send_reset(sk, skb);
1273 discard:
1274         if (opt_skb)
1275                 __kfree_skb(opt_skb);
1276         kfree_skb(skb);
1277         return 0;
1278 csum_err:
1279         TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_CSUMERRORS);
1280         TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_INERRS);
1281         goto discard;
1282
1283
1284 ipv6_pktoptions:
1285         /* Do you ask, what is it?
1286
1287            1. skb was enqueued by tcp.
1288            2. skb is added to tail of read queue, rather than out of order.
1289            3. socket is not in passive state.
1290            4. Finally, it really contains options, which user wants to receive.
1291          */
1292         tp = tcp_sk(sk);
1293         if (TCP_SKB_CB(opt_skb)->end_seq == tp->rcv_nxt &&
1294             !((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN))) {
1295                 if (np->rxopt.bits.rxinfo || np->rxopt.bits.rxoinfo)
1296                         np->mcast_oif = tcp_v6_iif(opt_skb);
1297                 if (np->rxopt.bits.rxhlim || np->rxopt.bits.rxohlim)
1298                         np->mcast_hops = ipv6_hdr(opt_skb)->hop_limit;
1299                 if (np->rxopt.bits.rxflow || np->rxopt.bits.rxtclass)
1300                         np->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(opt_skb));
1301                 if (np->repflow)
1302                         np->flow_label = ip6_flowlabel(ipv6_hdr(opt_skb));
1303                 if (ipv6_opt_accepted(sk, opt_skb, &TCP_SKB_CB(opt_skb)->header.h6)) {
1304                         skb_set_owner_r(opt_skb, sk);
1305                         opt_skb = xchg(&np->pktoptions, opt_skb);
1306                 } else {
1307                         __kfree_skb(opt_skb);
1308                         opt_skb = xchg(&np->pktoptions, NULL);
1309                 }
1310         }
1311
1312         kfree_skb(opt_skb);
1313         return 0;
1314 }
1315
1316 static void tcp_v6_fill_cb(struct sk_buff *skb, const struct ipv6hdr *hdr,
1317                            const struct tcphdr *th)
1318 {
1319         /* This is tricky: we move IP6CB at its correct location into
1320          * TCP_SKB_CB(). It must be done after xfrm6_policy_check(), because
1321          * _decode_session6() uses IP6CB().
1322          * barrier() makes sure compiler won't play aliasing games.
1323          */
1324         memmove(&TCP_SKB_CB(skb)->header.h6, IP6CB(skb),
1325                 sizeof(struct inet6_skb_parm));
1326         barrier();
1327
1328         TCP_SKB_CB(skb)->seq = ntohl(th->seq);
1329         TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
1330                                     skb->len - th->doff*4);
1331         TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
1332         TCP_SKB_CB(skb)->tcp_flags = tcp_flag_byte(th);
1333         TCP_SKB_CB(skb)->tcp_tw_isn = 0;
1334         TCP_SKB_CB(skb)->ip_dsfield = ipv6_get_dsfield(hdr);
1335         TCP_SKB_CB(skb)->sacked = 0;
1336 }
1337
1338 static void tcp_v6_restore_cb(struct sk_buff *skb)
1339 {
1340         /* We need to move header back to the beginning if xfrm6_policy_check()
1341          * and tcp_v6_fill_cb() are going to be called again.
1342          */
1343         memmove(IP6CB(skb), &TCP_SKB_CB(skb)->header.h6,
1344                 sizeof(struct inet6_skb_parm));
1345 }
1346
1347 static int tcp_v6_rcv(struct sk_buff *skb)
1348 {
1349         const struct tcphdr *th;
1350         const struct ipv6hdr *hdr;
1351         bool refcounted;
1352         struct sock *sk;
1353         int ret;
1354         struct net *net = dev_net(skb->dev);
1355
1356         if (skb->pkt_type != PACKET_HOST)
1357                 goto discard_it;
1358
1359         /*
1360          *      Count it even if it's bad.
1361          */
1362         TCP_INC_STATS_BH(net, TCP_MIB_INSEGS);
1363
1364         if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
1365                 goto discard_it;
1366
1367         th = tcp_hdr(skb);
1368
1369         if (th->doff < sizeof(struct tcphdr)/4)
1370                 goto bad_packet;
1371         if (!pskb_may_pull(skb, th->doff*4))
1372                 goto discard_it;
1373
1374         if (skb_checksum_init(skb, IPPROTO_TCP, ip6_compute_pseudo))
1375                 goto csum_error;
1376
1377         th = tcp_hdr(skb);
1378         hdr = ipv6_hdr(skb);
1379
1380 lookup:
1381         sk = __inet6_lookup_skb(&tcp_hashinfo, skb, __tcp_hdrlen(th),
1382                                 th->source, th->dest, inet6_iif(skb),
1383                                 &refcounted);
1384         if (!sk)
1385                 goto no_tcp_socket;
1386
1387 process:
1388         if (sk->sk_state == TCP_TIME_WAIT)
1389                 goto do_time_wait;
1390
1391         if (sk->sk_state == TCP_NEW_SYN_RECV) {
1392                 struct request_sock *req = inet_reqsk(sk);
1393                 struct sock *nsk;
1394
1395                 sk = req->rsk_listener;
1396                 tcp_v6_fill_cb(skb, hdr, th);
1397                 if (tcp_v6_inbound_md5_hash(sk, skb)) {
1398                         reqsk_put(req);
1399                         goto discard_it;
1400                 }
1401                 if (unlikely(sk->sk_state != TCP_LISTEN)) {
1402                         inet_csk_reqsk_queue_drop_and_put(sk, req);
1403                         goto lookup;
1404                 }
1405                 sock_hold(sk);
1406                 refcounted = true;
1407                 nsk = tcp_check_req(sk, skb, req, false);
1408                 if (!nsk) {
1409                         reqsk_put(req);
1410                         goto discard_and_relse;
1411                 }
1412                 if (nsk == sk) {
1413                         reqsk_put(req);
1414                         tcp_v6_restore_cb(skb);
1415                 } else if (tcp_child_process(sk, nsk, skb)) {
1416                         tcp_v6_send_reset(nsk, skb);
1417                         goto discard_and_relse;
1418                 } else {
1419                         sock_put(sk);
1420                         return 0;
1421                 }
1422         }
1423         if (hdr->hop_limit < inet6_sk(sk)->min_hopcount) {
1424                 NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP);
1425                 goto discard_and_relse;
1426         }
1427
1428         if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb))
1429                 goto discard_and_relse;
1430
1431         tcp_v6_fill_cb(skb, hdr, th);
1432
1433         if (tcp_v6_inbound_md5_hash(sk, skb))
1434                 goto discard_and_relse;
1435
1436         if (sk_filter(sk, skb))
1437                 goto discard_and_relse;
1438
1439         skb->dev = NULL;
1440
1441         if (sk->sk_state == TCP_LISTEN) {
1442                 ret = tcp_v6_do_rcv(sk, skb);
1443                 goto put_and_return;
1444         }
1445
1446         sk_incoming_cpu_update(sk);
1447
1448         bh_lock_sock_nested(sk);
1449         tcp_segs_in(tcp_sk(sk), skb);
1450         ret = 0;
1451         if (!sock_owned_by_user(sk)) {
1452                 if (!tcp_prequeue(sk, skb))
1453                         ret = tcp_v6_do_rcv(sk, skb);
1454         } else if (unlikely(sk_add_backlog(sk, skb,
1455                                            sk->sk_rcvbuf + sk->sk_sndbuf))) {
1456                 bh_unlock_sock(sk);
1457                 NET_INC_STATS_BH(net, LINUX_MIB_TCPBACKLOGDROP);
1458                 goto discard_and_relse;
1459         }
1460         bh_unlock_sock(sk);
1461
1462 put_and_return:
1463         if (refcounted)
1464                 sock_put(sk);
1465         return ret ? -1 : 0;
1466
1467 no_tcp_socket:
1468         if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb))
1469                 goto discard_it;
1470
1471         tcp_v6_fill_cb(skb, hdr, th);
1472
1473         if (tcp_checksum_complete(skb)) {
1474 csum_error:
1475                 TCP_INC_STATS_BH(net, TCP_MIB_CSUMERRORS);
1476 bad_packet:
1477                 TCP_INC_STATS_BH(net, TCP_MIB_INERRS);
1478         } else {
1479                 tcp_v6_send_reset(NULL, skb);
1480         }
1481
1482 discard_it:
1483         kfree_skb(skb);
1484         return 0;
1485
1486 discard_and_relse:
1487         sk_drops_add(sk, skb);
1488         if (refcounted)
1489                 sock_put(sk);
1490         goto discard_it;
1491
1492 do_time_wait:
1493         if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
1494                 inet_twsk_put(inet_twsk(sk));
1495                 goto discard_it;
1496         }
1497
1498         tcp_v6_fill_cb(skb, hdr, th);
1499
1500         if (tcp_checksum_complete(skb)) {
1501                 inet_twsk_put(inet_twsk(sk));
1502                 goto csum_error;
1503         }
1504
1505         switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) {
1506         case TCP_TW_SYN:
1507         {
1508                 struct sock *sk2;
1509
1510                 sk2 = inet6_lookup_listener(dev_net(skb->dev), &tcp_hashinfo,
1511                                             skb, __tcp_hdrlen(th),
1512                                             &ipv6_hdr(skb)->saddr, th->source,
1513                                             &ipv6_hdr(skb)->daddr,
1514                                             ntohs(th->dest), tcp_v6_iif(skb));
1515                 if (sk2) {
1516                         struct inet_timewait_sock *tw = inet_twsk(sk);
1517                         inet_twsk_deschedule_put(tw);
1518                         sk = sk2;
1519                         tcp_v6_restore_cb(skb);
1520                         refcounted = false;
1521                         goto process;
1522                 }
1523                 /* Fall through to ACK */
1524         }
1525         case TCP_TW_ACK:
1526                 tcp_v6_timewait_ack(sk, skb);
1527                 break;
1528         case TCP_TW_RST:
1529                 tcp_v6_restore_cb(skb);
1530                 tcp_v6_send_reset(sk, skb);
1531                 inet_twsk_deschedule_put(inet_twsk(sk));
1532                 goto discard_it;
1533         case TCP_TW_SUCCESS:
1534                 ;
1535         }
1536         goto discard_it;
1537 }
1538
1539 static void tcp_v6_early_demux(struct sk_buff *skb)
1540 {
1541         const struct ipv6hdr *hdr;
1542         const struct tcphdr *th;
1543         struct sock *sk;
1544
1545         if (skb->pkt_type != PACKET_HOST)
1546                 return;
1547
1548         if (!pskb_may_pull(skb, skb_transport_offset(skb) + sizeof(struct tcphdr)))
1549                 return;
1550
1551         hdr = ipv6_hdr(skb);
1552         th = tcp_hdr(skb);
1553
1554         if (th->doff < sizeof(struct tcphdr) / 4)
1555                 return;
1556
1557         /* Note : We use inet6_iif() here, not tcp_v6_iif() */
1558         sk = __inet6_lookup_established(dev_net(skb->dev), &tcp_hashinfo,
1559                                         &hdr->saddr, th->source,
1560                                         &hdr->daddr, ntohs(th->dest),
1561                                         inet6_iif(skb));
1562         if (sk) {
1563                 skb->sk = sk;
1564                 skb->destructor = sock_edemux;
1565                 if (sk_fullsock(sk)) {
1566                         struct dst_entry *dst = READ_ONCE(sk->sk_rx_dst);
1567
1568                         if (dst)
1569                                 dst = dst_check(dst, inet6_sk(sk)->rx_dst_cookie);
1570                         if (dst &&
1571                             inet_sk(sk)->rx_dst_ifindex == skb->skb_iif)
1572                                 skb_dst_set_noref(skb, dst);
1573                 }
1574         }
1575 }
1576
1577 static struct timewait_sock_ops tcp6_timewait_sock_ops = {
1578         .twsk_obj_size  = sizeof(struct tcp6_timewait_sock),
1579         .twsk_unique    = tcp_twsk_unique,
1580         .twsk_destructor = tcp_twsk_destructor,
1581 };
1582
1583 static const struct inet_connection_sock_af_ops ipv6_specific = {
1584         .queue_xmit        = inet6_csk_xmit,
1585         .send_check        = tcp_v6_send_check,
1586         .rebuild_header    = inet6_sk_rebuild_header,
1587         .sk_rx_dst_set     = inet6_sk_rx_dst_set,
1588         .conn_request      = tcp_v6_conn_request,
1589         .syn_recv_sock     = tcp_v6_syn_recv_sock,
1590         .net_header_len    = sizeof(struct ipv6hdr),
1591         .net_frag_header_len = sizeof(struct frag_hdr),
1592         .setsockopt        = ipv6_setsockopt,
1593         .getsockopt        = ipv6_getsockopt,
1594         .addr2sockaddr     = inet6_csk_addr2sockaddr,
1595         .sockaddr_len      = sizeof(struct sockaddr_in6),
1596         .bind_conflict     = inet6_csk_bind_conflict,
1597 #ifdef CONFIG_COMPAT
1598         .compat_setsockopt = compat_ipv6_setsockopt,
1599         .compat_getsockopt = compat_ipv6_getsockopt,
1600 #endif
1601         .mtu_reduced       = tcp_v6_mtu_reduced,
1602 };
1603
1604 #ifdef CONFIG_TCP_MD5SIG
1605 static const struct tcp_sock_af_ops tcp_sock_ipv6_specific = {
1606         .md5_lookup     =       tcp_v6_md5_lookup,
1607         .calc_md5_hash  =       tcp_v6_md5_hash_skb,
1608         .md5_parse      =       tcp_v6_parse_md5_keys,
1609 };
1610 #endif
1611
1612 /*
1613  *      TCP over IPv4 via INET6 API
1614  */
1615 static const struct inet_connection_sock_af_ops ipv6_mapped = {
1616         .queue_xmit        = ip_queue_xmit,
1617         .send_check        = tcp_v4_send_check,
1618         .rebuild_header    = inet_sk_rebuild_header,
1619         .sk_rx_dst_set     = inet_sk_rx_dst_set,
1620         .conn_request      = tcp_v6_conn_request,
1621         .syn_recv_sock     = tcp_v6_syn_recv_sock,
1622         .net_header_len    = sizeof(struct iphdr),
1623         .setsockopt        = ipv6_setsockopt,
1624         .getsockopt        = ipv6_getsockopt,
1625         .addr2sockaddr     = inet6_csk_addr2sockaddr,
1626         .sockaddr_len      = sizeof(struct sockaddr_in6),
1627         .bind_conflict     = inet6_csk_bind_conflict,
1628 #ifdef CONFIG_COMPAT
1629         .compat_setsockopt = compat_ipv6_setsockopt,
1630         .compat_getsockopt = compat_ipv6_getsockopt,
1631 #endif
1632         .mtu_reduced       = tcp_v4_mtu_reduced,
1633 };
1634
1635 #ifdef CONFIG_TCP_MD5SIG
1636 static const struct tcp_sock_af_ops tcp_sock_ipv6_mapped_specific = {
1637         .md5_lookup     =       tcp_v4_md5_lookup,
1638         .calc_md5_hash  =       tcp_v4_md5_hash_skb,
1639         .md5_parse      =       tcp_v6_parse_md5_keys,
1640 };
1641 #endif
1642
1643 /* NOTE: A lot of things set to zero explicitly by call to
1644  *       sk_alloc() so need not be done here.
1645  */
1646 static int tcp_v6_init_sock(struct sock *sk)
1647 {
1648         struct inet_connection_sock *icsk = inet_csk(sk);
1649
1650         tcp_init_sock(sk);
1651
1652         icsk->icsk_af_ops = &ipv6_specific;
1653
1654 #ifdef CONFIG_TCP_MD5SIG
1655         tcp_sk(sk)->af_specific = &tcp_sock_ipv6_specific;
1656 #endif
1657
1658         return 0;
1659 }
1660
1661 static void tcp_v6_destroy_sock(struct sock *sk)
1662 {
1663         tcp_v4_destroy_sock(sk);
1664         inet6_destroy_sock(sk);
1665 }
1666
1667 #ifdef CONFIG_PROC_FS
1668 /* Proc filesystem TCPv6 sock list dumping. */
1669 static void get_openreq6(struct seq_file *seq,
1670                          const struct request_sock *req, int i)
1671 {
1672         long ttd = req->rsk_timer.expires - jiffies;
1673         const struct in6_addr *src = &inet_rsk(req)->ir_v6_loc_addr;
1674         const struct in6_addr *dest = &inet_rsk(req)->ir_v6_rmt_addr;
1675
1676         if (ttd < 0)
1677                 ttd = 0;
1678
1679         seq_printf(seq,
1680                    "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
1681                    "%02X %08X:%08X %02X:%08lX %08X %5u %8d %d %d %pK\n",
1682                    i,
1683                    src->s6_addr32[0], src->s6_addr32[1],
1684                    src->s6_addr32[2], src->s6_addr32[3],
1685                    inet_rsk(req)->ir_num,
1686                    dest->s6_addr32[0], dest->s6_addr32[1],
1687                    dest->s6_addr32[2], dest->s6_addr32[3],
1688                    ntohs(inet_rsk(req)->ir_rmt_port),
1689                    TCP_SYN_RECV,
1690                    0, 0, /* could print option size, but that is af dependent. */
1691                    1,   /* timers active (only the expire timer) */
1692                    jiffies_to_clock_t(ttd),
1693                    req->num_timeout,
1694                    from_kuid_munged(seq_user_ns(seq),
1695                                     sock_i_uid(req->rsk_listener)),
1696                    0,  /* non standard timer */
1697                    0, /* open_requests have no inode */
1698                    0, req);
1699 }
1700
1701 static void get_tcp6_sock(struct seq_file *seq, struct sock *sp, int i)
1702 {
1703         const struct in6_addr *dest, *src;
1704         __u16 destp, srcp;
1705         int timer_active;
1706         unsigned long timer_expires;
1707         const struct inet_sock *inet = inet_sk(sp);
1708         const struct tcp_sock *tp = tcp_sk(sp);
1709         const struct inet_connection_sock *icsk = inet_csk(sp);
1710         const struct fastopen_queue *fastopenq = &icsk->icsk_accept_queue.fastopenq;
1711         int rx_queue;
1712         int state;
1713
1714         dest  = &sp->sk_v6_daddr;
1715         src   = &sp->sk_v6_rcv_saddr;
1716         destp = ntohs(inet->inet_dport);
1717         srcp  = ntohs(inet->inet_sport);
1718
1719         if (icsk->icsk_pending == ICSK_TIME_RETRANS) {
1720                 timer_active    = 1;
1721                 timer_expires   = icsk->icsk_timeout;
1722         } else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
1723                 timer_active    = 4;
1724                 timer_expires   = icsk->icsk_timeout;
1725         } else if (timer_pending(&sp->sk_timer)) {
1726                 timer_active    = 2;
1727                 timer_expires   = sp->sk_timer.expires;
1728         } else {
1729                 timer_active    = 0;
1730                 timer_expires = jiffies;
1731         }
1732
1733         state = sk_state_load(sp);
1734         if (state == TCP_LISTEN)
1735                 rx_queue = sp->sk_ack_backlog;
1736         else
1737                 /* Because we don't lock the socket,
1738                  * we might find a transient negative value.
1739                  */
1740                 rx_queue = max_t(int, tp->rcv_nxt - tp->copied_seq, 0);
1741
1742         seq_printf(seq,
1743                    "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
1744                    "%02X %08X:%08X %02X:%08lX %08X %5u %8d %lu %d %pK %lu %lu %u %u %d\n",
1745                    i,
1746                    src->s6_addr32[0], src->s6_addr32[1],
1747                    src->s6_addr32[2], src->s6_addr32[3], srcp,
1748                    dest->s6_addr32[0], dest->s6_addr32[1],
1749                    dest->s6_addr32[2], dest->s6_addr32[3], destp,
1750                    state,
1751                    tp->write_seq - tp->snd_una,
1752                    rx_queue,
1753                    timer_active,
1754                    jiffies_delta_to_clock_t(timer_expires - jiffies),
1755                    icsk->icsk_retransmits,
1756                    from_kuid_munged(seq_user_ns(seq), sock_i_uid(sp)),
1757                    icsk->icsk_probes_out,
1758                    sock_i_ino(sp),
1759                    atomic_read(&sp->sk_refcnt), sp,
1760                    jiffies_to_clock_t(icsk->icsk_rto),
1761                    jiffies_to_clock_t(icsk->icsk_ack.ato),
1762                    (icsk->icsk_ack.quick << 1) | icsk->icsk_ack.pingpong,
1763                    tp->snd_cwnd,
1764                    state == TCP_LISTEN ?
1765                         fastopenq->max_qlen :
1766                         (tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh)
1767                    );
1768 }
1769
1770 static void get_timewait6_sock(struct seq_file *seq,
1771                                struct inet_timewait_sock *tw, int i)
1772 {
1773         long delta = tw->tw_timer.expires - jiffies;
1774         const struct in6_addr *dest, *src;
1775         __u16 destp, srcp;
1776
1777         dest = &tw->tw_v6_daddr;
1778         src  = &tw->tw_v6_rcv_saddr;
1779         destp = ntohs(tw->tw_dport);
1780         srcp  = ntohs(tw->tw_sport);
1781
1782         seq_printf(seq,
1783                    "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
1784                    "%02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK\n",
1785                    i,
1786                    src->s6_addr32[0], src->s6_addr32[1],
1787                    src->s6_addr32[2], src->s6_addr32[3], srcp,
1788                    dest->s6_addr32[0], dest->s6_addr32[1],
1789                    dest->s6_addr32[2], dest->s6_addr32[3], destp,
1790                    tw->tw_substate, 0, 0,
1791                    3, jiffies_delta_to_clock_t(delta), 0, 0, 0, 0,
1792                    atomic_read(&tw->tw_refcnt), tw);
1793 }
1794
1795 static int tcp6_seq_show(struct seq_file *seq, void *v)
1796 {
1797         struct tcp_iter_state *st;
1798         struct sock *sk = v;
1799
1800         if (v == SEQ_START_TOKEN) {
1801                 seq_puts(seq,
1802                          "  sl  "
1803                          "local_address                         "
1804                          "remote_address                        "
1805                          "st tx_queue rx_queue tr tm->when retrnsmt"
1806                          "   uid  timeout inode\n");
1807                 goto out;
1808         }
1809         st = seq->private;
1810
1811         if (sk->sk_state == TCP_TIME_WAIT)
1812                 get_timewait6_sock(seq, v, st->num);
1813         else if (sk->sk_state == TCP_NEW_SYN_RECV)
1814                 get_openreq6(seq, v, st->num);
1815         else
1816                 get_tcp6_sock(seq, v, st->num);
1817 out:
1818         return 0;
1819 }
1820
1821 static const struct file_operations tcp6_afinfo_seq_fops = {
1822         .owner   = THIS_MODULE,
1823         .open    = tcp_seq_open,
1824         .read    = seq_read,
1825         .llseek  = seq_lseek,
1826         .release = seq_release_net
1827 };
1828
1829 static struct tcp_seq_afinfo tcp6_seq_afinfo = {
1830         .name           = "tcp6",
1831         .family         = AF_INET6,
1832         .seq_fops       = &tcp6_afinfo_seq_fops,
1833         .seq_ops        = {
1834                 .show           = tcp6_seq_show,
1835         },
1836 };
1837
1838 int __net_init tcp6_proc_init(struct net *net)
1839 {
1840         return tcp_proc_register(net, &tcp6_seq_afinfo);
1841 }
1842
1843 void tcp6_proc_exit(struct net *net)
1844 {
1845         tcp_proc_unregister(net, &tcp6_seq_afinfo);
1846 }
1847 #endif
1848
1849 static void tcp_v6_clear_sk(struct sock *sk, int size)
1850 {
1851         struct inet_sock *inet = inet_sk(sk);
1852
1853         /* we do not want to clear pinet6 field, because of RCU lookups */
1854         sk_prot_clear_nulls(sk, offsetof(struct inet_sock, pinet6));
1855
1856         size -= offsetof(struct inet_sock, pinet6) + sizeof(inet->pinet6);
1857         memset(&inet->pinet6 + 1, 0, size);
1858 }
1859
1860 struct proto tcpv6_prot = {
1861         .name                   = "TCPv6",
1862         .owner                  = THIS_MODULE,
1863         .close                  = tcp_close,
1864         .connect                = tcp_v6_connect,
1865         .disconnect             = tcp_disconnect,
1866         .accept                 = inet_csk_accept,
1867         .ioctl                  = tcp_ioctl,
1868         .init                   = tcp_v6_init_sock,
1869         .destroy                = tcp_v6_destroy_sock,
1870         .shutdown               = tcp_shutdown,
1871         .setsockopt             = tcp_setsockopt,
1872         .getsockopt             = tcp_getsockopt,
1873         .recvmsg                = tcp_recvmsg,
1874         .sendmsg                = tcp_sendmsg,
1875         .sendpage               = tcp_sendpage,
1876         .backlog_rcv            = tcp_v6_do_rcv,
1877         .release_cb             = tcp_release_cb,
1878         .hash                   = inet6_hash,
1879         .unhash                 = inet_unhash,
1880         .get_port               = inet_csk_get_port,
1881         .enter_memory_pressure  = tcp_enter_memory_pressure,
1882         .stream_memory_free     = tcp_stream_memory_free,
1883         .sockets_allocated      = &tcp_sockets_allocated,
1884         .memory_allocated       = &tcp_memory_allocated,
1885         .memory_pressure        = &tcp_memory_pressure,
1886         .orphan_count           = &tcp_orphan_count,
1887         .sysctl_mem             = sysctl_tcp_mem,
1888         .sysctl_wmem            = sysctl_tcp_wmem,
1889         .sysctl_rmem            = sysctl_tcp_rmem,
1890         .max_header             = MAX_TCP_HEADER,
1891         .obj_size               = sizeof(struct tcp6_sock),
1892         .slab_flags             = SLAB_DESTROY_BY_RCU,
1893         .twsk_prot              = &tcp6_timewait_sock_ops,
1894         .rsk_prot               = &tcp6_request_sock_ops,
1895         .h.hashinfo             = &tcp_hashinfo,
1896         .no_autobind            = true,
1897 #ifdef CONFIG_COMPAT
1898         .compat_setsockopt      = compat_tcp_setsockopt,
1899         .compat_getsockopt      = compat_tcp_getsockopt,
1900 #endif
1901         .clear_sk               = tcp_v6_clear_sk,
1902         .diag_destroy           = tcp_abort,
1903 };
1904
1905 static const struct inet6_protocol tcpv6_protocol = {
1906         .early_demux    =       tcp_v6_early_demux,
1907         .handler        =       tcp_v6_rcv,
1908         .err_handler    =       tcp_v6_err,
1909         .flags          =       INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
1910 };
1911
1912 static struct inet_protosw tcpv6_protosw = {
1913         .type           =       SOCK_STREAM,
1914         .protocol       =       IPPROTO_TCP,
1915         .prot           =       &tcpv6_prot,
1916         .ops            =       &inet6_stream_ops,
1917         .flags          =       INET_PROTOSW_PERMANENT |
1918                                 INET_PROTOSW_ICSK,
1919 };
1920
1921 static int __net_init tcpv6_net_init(struct net *net)
1922 {
1923         return inet_ctl_sock_create(&net->ipv6.tcp_sk, PF_INET6,
1924                                     SOCK_RAW, IPPROTO_TCP, net);
1925 }
1926
1927 static void __net_exit tcpv6_net_exit(struct net *net)
1928 {
1929         inet_ctl_sock_destroy(net->ipv6.tcp_sk);
1930 }
1931
1932 static void __net_exit tcpv6_net_exit_batch(struct list_head *net_exit_list)
1933 {
1934         inet_twsk_purge(&tcp_hashinfo, &tcp_death_row, AF_INET6);
1935 }
1936
1937 static struct pernet_operations tcpv6_net_ops = {
1938         .init       = tcpv6_net_init,
1939         .exit       = tcpv6_net_exit,
1940         .exit_batch = tcpv6_net_exit_batch,
1941 };
1942
1943 int __init tcpv6_init(void)
1944 {
1945         int ret;
1946
1947         ret = inet6_add_protocol(&tcpv6_protocol, IPPROTO_TCP);
1948         if (ret)
1949                 goto out;
1950
1951         /* register inet6 protocol */
1952         ret = inet6_register_protosw(&tcpv6_protosw);
1953         if (ret)
1954                 goto out_tcpv6_protocol;
1955
1956         ret = register_pernet_subsys(&tcpv6_net_ops);
1957         if (ret)
1958                 goto out_tcpv6_protosw;
1959 out:
1960         return ret;
1961
1962 out_tcpv6_protosw:
1963         inet6_unregister_protosw(&tcpv6_protosw);
1964 out_tcpv6_protocol:
1965         inet6_del_protocol(&tcpv6_protocol, IPPROTO_TCP);
1966         goto out;
1967 }
1968
1969 void tcpv6_exit(void)
1970 {
1971         unregister_pernet_subsys(&tcpv6_net_ops);
1972         inet6_unregister_protosw(&tcpv6_protosw);
1973         inet6_del_protocol(&tcpv6_protocol, IPPROTO_TCP);
1974 }