net/ipv6/tcp_ipv6.c

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