net/ipv6/tcp_ipv6.c

   1 /*
   2  *      TCP over IPv6
   3  *      Linux INET6 implementation
   4  *
   5  *      Authors:
   6  *      Pedro Roque             <roque@di.fc.ul.pt>
   7  *
   8  *      Based on:
   9  *      linux/net/ipv4/tcp.c
  10  *      linux/net/ipv4/tcp_input.c
  11  *      linux/net/ipv4/tcp_output.c
  12  *
  13  *      Fixes:
  14  *      Hideaki YOSHIFUJI       :       sin6_scope_id support
  15  *      YOSHIFUJI Hideaki @USAGI and:   Support IPV6_V6ONLY socket option, which
  16  *      Alexey Kuznetsov                allow both IPv4 and IPv6 sockets to bind
  17  *                                      a single port at the same time.
  18  *      YOSHIFUJI Hideaki @USAGI:       convert /proc/net/tcp6 to seq_file.
  19  *
  20  *      This program is free software; you can redistribute it and/or
  21  *      modify it under the terms of the GNU General Public License
  22  *      as published by the Free Software Foundation; either version
  23  *      2 of the License, or (at your option) any later version.
  24  */
  25
  26 #include <linux/bottom_half.h>
  27 #include <linux/module.h>
  28 #include <linux/errno.h>
  29 #include <linux/types.h>
  30 #include <linux/socket.h>
  31 #include <linux/sockios.h>
  32 #include <linux/net.h>
  33 #include <linux/jiffies.h>
  34 #include <linux/in.h>
  35 #include <linux/in6.h>
  36 #include <linux/netdevice.h>
  37 #include <linux/init.h>
  38 #include <linux/jhash.h>
  39 #include <linux/ipsec.h>
  40 #include <linux/times.h>
  41 #include <linux/slab.h>
  42 #include <linux/uaccess.h>
  43 #include <linux/ipv6.h>
  44 #include <linux/icmpv6.h>
  45 #include <linux/random.h>
  46
  47 #include <net/tcp.h>
  48 #include <net/ndisc.h>
  49 #include <net/inet6_hashtables.h>
  50 #include <net/inet6_connection_sock.h>
  51 #include <net/ipv6.h>
  52 #include <net/transp_v6.h>
  53 #include <net/addrconf.h>
  54 #include <net/ip6_route.h>
  55 #include <net/ip6_checksum.h>
  56 #include <net/inet_ecn.h>
  57 #include <net/protocol.h>
  58 #include <net/xfrm.h>
  59 #include <net/snmp.h>
  60 #include <net/dsfield.h>
  61 #include <net/timewait_sock.h>
  62 #include <net/inet_common.h>
  63 #include <net/secure_seq.h>
  64 #include <net/busy_poll.h>
  65
  66 #include <linux/proc_fs.h>
  67 #include <linux/seq_file.h>
  68
  69 #include <crypto/hash.h>
  70 #include <linux/scatterlist.h>
  71
  72 static void     tcp_v6_send_reset(const struct sock *sk, struct sk_buff *skb);
  73 static void     tcp_v6_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb,
  74                                       struct request_sock *req);
  75
  76 static int      tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb);
  77
  78 static const struct inet_connection_sock_af_ops ipv6_mapped;
  79 static const struct inet_connection_sock_af_ops ipv6_specific;
  80 #ifdef CONFIG_TCP_MD5SIG
  81 static const struct tcp_sock_af_ops tcp_sock_ipv6_specific;
  82 static const struct tcp_sock_af_ops tcp_sock_ipv6_mapped_specific;
  83 #else
  84 static struct tcp_md5sig_key *tcp_v6_md5_do_lookup(const struct sock *sk,
  85                                                    const struct in6_addr *addr)
  86 {
  87         return NULL;
  88 }
  89 #endif
  90
  91 static void inet6_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb)
  92 {
  93         struct dst_entry *dst = skb_dst(skb);
  94
  95         if (dst && dst_hold_safe(dst)) {
  96                 const struct rt6_info *rt = (const struct rt6_info *)dst;
  97
  98                 sk->sk_rx_dst = dst;
  99                 inet_sk(sk)->rx_dst_ifindex = skb->skb_iif;
 100                 inet6_sk(sk)->rx_dst_cookie = rt6_get_cookie(rt);
 101         }
 102 }
 103
 104 static __u32 tcp_v6_init_sequence(const struct sk_buff *skb)
 105 {
 106         return secure_tcpv6_sequence_number(ipv6_hdr(skb)->daddr.s6_addr32,
 107                                             ipv6_hdr(skb)->saddr.s6_addr32,
 108                                             tcp_hdr(skb)->dest,
 109                                             tcp_hdr(skb)->source);
 110 }
 111
 112 static int tcp_v6_connect(struct sock *sk, struct sockaddr *uaddr,
 113                           int addr_len)
 114 {
 115         struct sockaddr_in6 *usin = (struct sockaddr_in6 *) uaddr;
 116         struct inet_sock *inet = inet_sk(sk);
 117         struct inet_connection_sock *icsk = inet_csk(sk);
 118         struct ipv6_pinfo *np = inet6_sk(sk);
 119         struct tcp_sock *tp = tcp_sk(sk);
 120         struct in6_addr *saddr = NULL, *final_p, final;
 121         struct ipv6_txoptions *opt;
 122         struct flowi6 fl6;
 123         struct dst_entry *dst;
 124         int addr_type;
 125         int err;
 126
 127         if (addr_len < SIN6_LEN_RFC2133)
 128                 return -EINVAL;
 129
 130         if (usin->sin6_family != AF_INET6)
 131                 return -EAFNOSUPPORT;
 132
 133         memset(&fl6, 0, sizeof(fl6));
 134
 135         if (np->sndflow) {
 136                 fl6.flowlabel = usin->sin6_flowinfo&IPV6_FLOWINFO_MASK;
 137                 IP6_ECN_flow_init(fl6.flowlabel);
 138                 if (fl6.flowlabel&IPV6_FLOWLABEL_MASK) {
 139                         struct ip6_flowlabel *flowlabel;
 140                         flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
 141                         if (!flowlabel)
 142                                 return -EINVAL;
 143                         fl6_sock_release(flowlabel);
 144                 }
 145         }
 146
 147         /*
 148          *      connect() to INADDR_ANY means loopback (BSD'ism).
 149          */
 150
 151         if (ipv6_addr_any(&usin->sin6_addr))
 152                 usin->sin6_addr.s6_addr[15] = 0x1;
 153
 154         addr_type = ipv6_addr_type(&usin->sin6_addr);
 155
 156         if (addr_type & IPV6_ADDR_MULTICAST)
 157                 return -ENETUNREACH;
 158
 159         if (addr_type&IPV6_ADDR_LINKLOCAL) {
 160                 if (addr_len >= sizeof(struct sockaddr_in6) &&
 161                     usin->sin6_scope_id) {
 162                         /* If interface is set while binding, indices
 163                          * must coincide.
 164                          */
 165                         if (sk->sk_bound_dev_if &&
 166                             sk->sk_bound_dev_if != usin->sin6_scope_id)
 167                                 return -EINVAL;
 168
 169                         sk->sk_bound_dev_if = usin->sin6_scope_id;
 170                 }
 171
 172                 /* Connect to link-local address requires an interface */
 173                 if (!sk->sk_bound_dev_if)
 174                         return -EINVAL;
 175         }
 176
 177         if (tp->rx_opt.ts_recent_stamp &&
 178             !ipv6_addr_equal(&sk->sk_v6_daddr, &usin->sin6_addr)) {
 179                 tp->rx_opt.ts_recent = 0;
 180                 tp->rx_opt.ts_recent_stamp = 0;
 181                 tp->write_seq = 0;
 182         }
 183
 184         sk->sk_v6_daddr = usin->sin6_addr;
 185         np->flow_label = fl6.flowlabel;
 186
 187         /*
 188          *      TCP over IPv4
 189          */
 190
 191         if (addr_type == IPV6_ADDR_MAPPED) {
 192                 u32 exthdrlen = icsk->icsk_ext_hdr_len;
 193                 struct sockaddr_in sin;
 194
 195                 SOCK_DEBUG(sk, "connect: ipv4 mapped\n");
 196
 197                 if (__ipv6_only_sock(sk))
 198                         return -ENETUNREACH;
 199
 200                 sin.sin_family = AF_INET;
 201                 sin.sin_port = usin->sin6_port;
 202                 sin.sin_addr.s_addr = usin->sin6_addr.s6_addr32[3];
 203
 204                 icsk->icsk_af_ops = &ipv6_mapped;
 205                 sk->sk_backlog_rcv = tcp_v4_do_rcv;
 206 #ifdef CONFIG_TCP_MD5SIG
 207                 tp->af_specific = &tcp_sock_ipv6_mapped_specific;
 208 #endif
 209
 210                 err = tcp_v4_connect(sk, (struct sockaddr *)&sin, sizeof(sin));
 211
 212                 if (err) {
 213                         icsk->icsk_ext_hdr_len = exthdrlen;
 214                         icsk->icsk_af_ops = &ipv6_specific;
 215                         sk->sk_backlog_rcv = tcp_v6_do_rcv;
 216 #ifdef CONFIG_TCP_MD5SIG
 217                         tp->af_specific = &tcp_sock_ipv6_specific;
 218 #endif
 219                         goto failure;
 220                 }
 221                 np->saddr = sk->sk_v6_rcv_saddr;
 222
 223                 return err;
 224         }
 225
 226         if (!ipv6_addr_any(&sk->sk_v6_rcv_saddr))
 227                 saddr = &sk->sk_v6_rcv_saddr;
 228
 229         fl6.flowi6_proto = IPPROTO_TCP;
 230         fl6.daddr = sk->sk_v6_daddr;
 231         fl6.saddr = saddr ? *saddr : np->saddr;
 232         fl6.flowi6_oif = sk->sk_bound_dev_if;
 233         fl6.flowi6_mark = sk->sk_mark;
 234         fl6.fl6_dport = usin->sin6_port;
 235         fl6.fl6_sport = inet->inet_sport;
 236
 237         opt = rcu_dereference_protected(np->opt, lockdep_sock_is_held(sk));
 238         final_p = fl6_update_dst(&fl6, opt, &final);
 239
 240         security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));
 241
 242         dst = ip6_dst_lookup_flow(sk, &fl6, final_p);
 243         if (IS_ERR(dst)) {
 244                 err = PTR_ERR(dst);
 245                 goto failure;
 246         }
 247
 248         if (!saddr) {
 249                 saddr = &fl6.saddr;
 250                 sk->sk_v6_rcv_saddr = *saddr;
 251         }
 252
 253         /* set the source address */
 254         np->saddr = *saddr;
 255         inet->inet_rcv_saddr = LOOPBACK4_IPV6;
 256
 257         sk->sk_gso_type = SKB_GSO_TCPV6;
 258         ip6_dst_store(sk, dst, NULL, NULL);
 259
 260         if (tcp_death_row.sysctl_tw_recycle &&
 261             !tp->rx_opt.ts_recent_stamp &&
 262             ipv6_addr_equal(&fl6.daddr, &sk->sk_v6_daddr))
 263                 tcp_fetch_timewait_stamp(sk, dst);
 264
 265         icsk->icsk_ext_hdr_len = 0;
 266         if (opt)
 267                 icsk->icsk_ext_hdr_len = opt->opt_flen +
 268                                          opt->opt_nflen;
 269
 270         tp->rx_opt.mss_clamp = IPV6_MIN_MTU - sizeof(struct tcphdr) - sizeof(struct ipv6hdr);
 271
 272         inet->inet_dport = usin->sin6_port;
 273
 274         tcp_set_state(sk, TCP_SYN_SENT);
 275         err = inet6_hash_connect(&tcp_death_row, sk);
 276         if (err)
 277                 goto late_failure;
 278
 279         sk_set_txhash(sk);
 280
 281         if (!tp->write_seq && likely(!tp->repair))
 282                 tp->write_seq = secure_tcpv6_sequence_number(np->saddr.s6_addr32,
 283                                                              sk->sk_v6_daddr.s6_addr32,
 284                                                              inet->inet_sport,
 285                                                              inet->inet_dport);
 286
 287         err = tcp_connect(sk);
 288         if (err)
 289                 goto late_failure;
 290
 291         return 0;
 292
 293 late_failure:
 294         tcp_set_state(sk, TCP_CLOSE);
 295         __sk_dst_reset(sk);
 296 failure:
 297         inet->inet_dport = 0;
 298         sk->sk_route_caps = 0;
 299         return err;
 300 }
 301
 302 static void tcp_v6_mtu_reduced(struct sock *sk)
 303 {
 304         struct dst_entry *dst;
 305
 306         if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE))
 307                 return;
 308
 309         dst = inet6_csk_update_pmtu(sk, tcp_sk(sk)->mtu_info);
 310         if (!dst)
 311                 return;
 312
 313         if (inet_csk(sk)->icsk_pmtu_cookie > dst_mtu(dst)) {
 314                 tcp_sync_mss(sk, dst_mtu(dst));
 315                 tcp_simple_retransmit(sk);
 316         }
 317 }
 318
 319 static void tcp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 320                 u8 type, u8 code, int offset, __be32 info)
 321 {
 322         const struct ipv6hdr *hdr = (const struct ipv6hdr *)skb->data;
 323         const struct tcphdr *th = (struct tcphdr *)(skb->data+offset);
 324         struct net *net = dev_net(skb->dev);
 325         struct request_sock *fastopen;
 326         struct ipv6_pinfo *np;
 327         struct tcp_sock *tp;
 328         __u32 seq, snd_una;
 329         struct sock *sk;
 330         bool fatal;
 331         int err;
 332
 333         sk = __inet6_lookup_established(net, &tcp_hashinfo,
 334                                         &hdr->daddr, th->dest,
 335                                         &hdr->saddr, ntohs(th->source),
 336                                         skb->dev->ifindex);
 337
 338         if (!sk) {
 339                 __ICMP6_INC_STATS(net, __in6_dev_get(skb->dev),
 340                                   ICMP6_MIB_INERRORS);
 341                 return;
 342         }
 343
 344         if (sk->sk_state == TCP_TIME_WAIT) {
 345                 inet_twsk_put(inet_twsk(sk));
 346                 return;
 347         }
 348         seq = ntohl(th->seq);
 349         fatal = icmpv6_err_convert(type, code, &err);
 350         if (sk->sk_state == TCP_NEW_SYN_RECV)
 351                 return tcp_req_err(sk, seq, fatal);
 352
 353         bh_lock_sock(sk);
 354         if (sock_owned_by_user(sk) && type != ICMPV6_PKT_TOOBIG)
 355                 __NET_INC_STATS(net, LINUX_MIB_LOCKDROPPEDICMPS);
 356
 357         if (sk->sk_state == TCP_CLOSE)
 358                 goto out;
 359
 360         if (ipv6_hdr(skb)->hop_limit < inet6_sk(sk)->min_hopcount) {
 361                 __NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP);
 362                 goto out;
 363         }
 364
 365         tp = tcp_sk(sk);
 366         /* XXX (TFO) - tp->snd_una should be ISN (tcp_create_openreq_child() */
 367         fastopen = tp->fastopen_rsk;
 368         snd_una = fastopen ? tcp_rsk(fastopen)->snt_isn : tp->snd_una;
 369         if (sk->sk_state != TCP_LISTEN &&
 370             !between(seq, snd_una, tp->snd_nxt)) {
 371                 __NET_INC_STATS(net, LINUX_MIB_OUTOFWINDOWICMPS);
 372                 goto out;
 373         }
 374
 375         np = inet6_sk(sk);
 376
 377         if (type == NDISC_REDIRECT) {
 378                 struct dst_entry *dst = __sk_dst_check(sk, np->dst_cookie);
 379
 380                 if (dst)
 381                         dst->ops->redirect(dst, sk, skb);
 382                 goto out;
 383         }
 384
 385         if (type == ICMPV6_PKT_TOOBIG) {
 386                 /* We are not interested in TCP_LISTEN and open_requests
 387                  * (SYN-ACKs send out by Linux are always <576bytes so
 388                  * they should go through unfragmented).
 389                  */
 390                 if (sk->sk_state == TCP_LISTEN)
 391                         goto out;
 392
 393                 if (!ip6_sk_accept_pmtu(sk))
 394                         goto out;
 395
 396                 tp->mtu_info = ntohl(info);
 397                 if (!sock_owned_by_user(sk))
 398                         tcp_v6_mtu_reduced(sk);
 399                 else if (!test_and_set_bit(TCP_MTU_REDUCED_DEFERRED,
 400                                            &tp->tsq_flags))
 401                         sock_hold(sk);
 402                 goto out;
 403         }
 404
 405
 406         /* Might be for an request_sock */
 407         switch (sk->sk_state) {
 408         case TCP_SYN_SENT:
 409         case TCP_SYN_RECV:
 410                 /* Only in fast or simultaneous open. If a fast open socket is
 411                  * is already accepted it is treated as a connected one below.
 412                  */
 413                 if (fastopen && !fastopen->sk)
 414                         break;
 415
 416                 if (!sock_owned_by_user(sk)) {
 417                         sk->sk_err = err;
 418                         sk->sk_error_report(sk);                /* Wake people up to see the error (see connect in sock.c) */
 419
 420                         tcp_done(sk);
 421                 } else
 422                         sk->sk_err_soft = err;
 423                 goto out;
 424         }
 425
 426         if (!sock_owned_by_user(sk) && np->recverr) {
 427                 sk->sk_err = err;
 428                 sk->sk_error_report(sk);
 429         } else
 430                 sk->sk_err_soft = err;
 431
 432 out:
 433         bh_unlock_sock(sk);
 434         sock_put(sk);
 435 }
 436
 437
 438 static int tcp_v6_send_synack(const struct sock *sk, struct dst_entry *dst,
 439                               struct flowi *fl,
 440                               struct request_sock *req,
 441                               struct tcp_fastopen_cookie *foc,
 442                               enum tcp_synack_type synack_type)
 443 {
 444         struct inet_request_sock *ireq = inet_rsk(req);
 445         struct ipv6_pinfo *np = inet6_sk(sk);
 446         struct ipv6_txoptions *opt;
 447         struct flowi6 *fl6 = &fl->u.ip6;
 448         struct sk_buff *skb;
 449         int err = -ENOMEM;
 450
 451         /* First, grab a route. */
 452         if (!dst && (dst = inet6_csk_route_req(sk, fl6, req,
 453                                                IPPROTO_TCP)) == NULL)
 454                 goto done;
 455
 456         skb = tcp_make_synack(sk, dst, req, foc, synack_type);
 457
 458         if (skb) {
 459                 __tcp_v6_send_check(skb, &ireq->ir_v6_loc_addr,
 460                                     &ireq->ir_v6_rmt_addr);
 461
 462                 fl6->daddr = ireq->ir_v6_rmt_addr;
 463                 if (np->repflow && ireq->pktopts)
 464                         fl6->flowlabel = ip6_flowlabel(ipv6_hdr(ireq->pktopts));
 465
 466                 rcu_read_lock();
 467                 opt = ireq->ipv6_opt;
 468                 if (!opt)
 469                         opt = rcu_dereference(np->opt);
 470                 err = ip6_xmit(sk, skb, fl6, opt, np->tclass);
 471                 rcu_read_unlock();
 472                 err = net_xmit_eval(err);
 473         }
 474
 475 done:
 476         return err;
 477 }
 478
 479
 480 static void tcp_v6_reqsk_destructor(struct request_sock *req)
 481 {
 482         kfree(inet_rsk(req)->ipv6_opt);
 483         kfree_skb(inet_rsk(req)->pktopts);
 484 }
 485
 486 #ifdef CONFIG_TCP_MD5SIG
 487 static struct tcp_md5sig_key *tcp_v6_md5_do_lookup(const struct sock *sk,
 488                                                    const struct in6_addr *addr)
 489 {
 490         return tcp_md5_do_lookup(sk, (union tcp_md5_addr *)addr, AF_INET6);
 491 }
 492
 493 static struct tcp_md5sig_key *tcp_v6_md5_lookup(const struct sock *sk,
 494                                                 const struct sock *addr_sk)
 495 {
 496         return tcp_v6_md5_do_lookup(sk, &addr_sk->sk_v6_daddr);
 497 }
 498
 499 static int tcp_v6_parse_md5_keys(struct sock *sk, char __user *optval,
 500                                  int optlen)
 501 {
 502         struct tcp_md5sig cmd;
 503         struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)&cmd.tcpm_addr;
 504
 505         if (optlen < sizeof(cmd))
 506                 return -EINVAL;
 507
 508         if (copy_from_user(&cmd, optval, sizeof(cmd)))
 509                 return -EFAULT;
 510
 511         if (sin6->sin6_family != AF_INET6)
 512                 return -EINVAL;
 513
 514         if (!cmd.tcpm_keylen) {
 515                 if (ipv6_addr_v4mapped(&sin6->sin6_addr))
 516                         return tcp_md5_do_del(sk, (union tcp_md5_addr *)&sin6->sin6_addr.s6_addr32[3],
 517                                               AF_INET);
 518                 return tcp_md5_do_del(sk, (union tcp_md5_addr *)&sin6->sin6_addr,
 519                                       AF_INET6);
 520         }
 521
 522         if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN)
 523                 return -EINVAL;
 524
 525         if (ipv6_addr_v4mapped(&sin6->sin6_addr))
 526                 return tcp_md5_do_add(sk, (union tcp_md5_addr *)&sin6->sin6_addr.s6_addr32[3],
 527                                       AF_INET, cmd.tcpm_key, cmd.tcpm_keylen, GFP_KERNEL);
 528
 529         return tcp_md5_do_add(sk, (union tcp_md5_addr *)&sin6->sin6_addr,
 530                               AF_INET6, cmd.tcpm_key, cmd.tcpm_keylen, GFP_KERNEL);
 531 }
 532
 533 static int tcp_v6_md5_hash_headers(struct tcp_md5sig_pool *hp,
 534                                    const struct in6_addr *daddr,
 535                                    const struct in6_addr *saddr,
 536                                    const struct tcphdr *th, int nbytes)
 537 {
 538         struct tcp6_pseudohdr *bp;
 539         struct scatterlist sg;
 540         struct tcphdr *_th;
 541
 542         bp = hp->scratch;
 543         /* 1. TCP pseudo-header (RFC2460) */
 544         bp->saddr = *saddr;
 545         bp->daddr = *daddr;
 546         bp->protocol = cpu_to_be32(IPPROTO_TCP);
 547         bp->len = cpu_to_be32(nbytes);
 548
 549         _th = (struct tcphdr *)(bp + 1);
 550         memcpy(_th, th, sizeof(*th));
 551         _th->check = 0;
 552
 553         sg_init_one(&sg, bp, sizeof(*bp) + sizeof(*th));
 554         ahash_request_set_crypt(hp->md5_req, &sg, NULL,
 555                                 sizeof(*bp) + sizeof(*th));
 556         return crypto_ahash_update(hp->md5_req);
 557 }
 558
 559 static int tcp_v6_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key,
 560                                const struct in6_addr *daddr, struct in6_addr *saddr,
 561                                const struct tcphdr *th)
 562 {
 563         struct tcp_md5sig_pool *hp;
 564         struct ahash_request *req;
 565
 566         hp = tcp_get_md5sig_pool();
 567         if (!hp)
 568                 goto clear_hash_noput;
 569         req = hp->md5_req;
 570
 571         if (crypto_ahash_init(req))
 572                 goto clear_hash;
 573         if (tcp_v6_md5_hash_headers(hp, daddr, saddr, th, th->doff << 2))
 574                 goto clear_hash;
 575         if (tcp_md5_hash_key(hp, key))
 576                 goto clear_hash;
 577         ahash_request_set_crypt(req, NULL, md5_hash, 0);
 578         if (crypto_ahash_final(req))
 579                 goto clear_hash;
 580
 581         tcp_put_md5sig_pool();
 582         return 0;
 583
 584 clear_hash:
 585         tcp_put_md5sig_pool();
 586 clear_hash_noput:
 587         memset(md5_hash, 0, 16);
 588         return 1;
 589 }
 590
 591 static int tcp_v6_md5_hash_skb(char *md5_hash,
 592                                const struct tcp_md5sig_key *key,
 593                                const struct sock *sk,
 594                                const struct sk_buff *skb)
 595 {
 596         const struct in6_addr *saddr, *daddr;
 597         struct tcp_md5sig_pool *hp;
 598         struct ahash_request *req;
 599         const struct tcphdr *th = tcp_hdr(skb);
 600
 601         if (sk) { /* valid for establish/request sockets */
 602                 saddr = &sk->sk_v6_rcv_saddr;
 603                 daddr = &sk->sk_v6_daddr;
 604         } else {
 605                 const struct ipv6hdr *ip6h = ipv6_hdr(skb);
 606                 saddr = &ip6h->saddr;
 607                 daddr = &ip6h->daddr;
 608         }
 609
 610         hp = tcp_get_md5sig_pool();
 611         if (!hp)
 612                 goto clear_hash_noput;
 613         req = hp->md5_req;
 614
 615         if (crypto_ahash_init(req))
 616                 goto clear_hash;
 617
 618         if (tcp_v6_md5_hash_headers(hp, daddr, saddr, th, skb->len))
 619                 goto clear_hash;
 620         if (tcp_md5_hash_skb_data(hp, skb, th->doff << 2))
 621                 goto clear_hash;
 622         if (tcp_md5_hash_key(hp, key))
 623                 goto clear_hash;
 624         ahash_request_set_crypt(req, NULL, md5_hash, 0);
 625         if (crypto_ahash_final(req))
 626                 goto clear_hash;
 627
 628         tcp_put_md5sig_pool();
 629         return 0;
 630
 631 clear_hash:
 632         tcp_put_md5sig_pool();
 633 clear_hash_noput:
 634         memset(md5_hash, 0, 16);
 635         return 1;
 636 }
 637
 638 #endif
 639
 640 static bool tcp_v6_inbound_md5_hash(const struct sock *sk,
 641                                     const struct sk_buff *skb)
 642 {
 643 #ifdef CONFIG_TCP_MD5SIG
 644         const __u8 *hash_location = NULL;
 645         struct tcp_md5sig_key *hash_expected;
 646         const struct ipv6hdr *ip6h = ipv6_hdr(skb);
 647         const struct tcphdr *th = tcp_hdr(skb);
 648         int genhash;
 649         u8 newhash[16];
 650
 651         hash_expected = tcp_v6_md5_do_lookup(sk, &ip6h->saddr);
 652         hash_location = tcp_parse_md5sig_option(th);
 653
 654         /* We've parsed the options - do we have a hash? */
 655         if (!hash_expected && !hash_location)
 656                 return false;
 657
 658         if (hash_expected && !hash_location) {
 659                 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5NOTFOUND);
 660                 return true;
 661         }
 662
 663         if (!hash_expected && hash_location) {
 664                 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5UNEXPECTED);
 665                 return true;
 666         }
 667
 668         /* check the signature */
 669         genhash = tcp_v6_md5_hash_skb(newhash,
 670                                       hash_expected,
 671                                       NULL, skb);
 672
 673         if (genhash || memcmp(hash_location, newhash, 16) != 0) {
 674                 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5FAILURE);
 675                 net_info_ratelimited("MD5 Hash %s for [%pI6c]:%u->[%pI6c]:%u\n",
 676                                      genhash ? "failed" : "mismatch",
 677                                      &ip6h->saddr, ntohs(th->source),
 678                                      &ip6h->daddr, ntohs(th->dest));
 679                 return true;
 680         }
 681 #endif
 682         return false;
 683 }
 684
 685 static void tcp_v6_init_req(struct request_sock *req,
 686                             const struct sock *sk_listener,
 687                             struct sk_buff *skb)
 688 {
 689         struct inet_request_sock *ireq = inet_rsk(req);
 690         const struct ipv6_pinfo *np = inet6_sk(sk_listener);
 691
 692         ireq->ir_v6_rmt_addr = ipv6_hdr(skb)->saddr;
 693         ireq->ir_v6_loc_addr = ipv6_hdr(skb)->daddr;
 694
 695         /* So that link locals have meaning */
 696         if (!sk_listener->sk_bound_dev_if &&
 697             ipv6_addr_type(&ireq->ir_v6_rmt_addr) & IPV6_ADDR_LINKLOCAL)
 698                 ireq->ir_iif = tcp_v6_iif(skb);
 699
 700         if (!TCP_SKB_CB(skb)->tcp_tw_isn &&
 701             (ipv6_opt_accepted(sk_listener, skb, &TCP_SKB_CB(skb)->header.h6) ||
 702              np->rxopt.bits.rxinfo ||
 703              np->rxopt.bits.rxoinfo || np->rxopt.bits.rxhlim ||
 704              np->rxopt.bits.rxohlim || np->repflow)) {
 705                 atomic_inc(&skb->users);
 706                 ireq->pktopts = skb;
 707         }
 708 }
 709
 710 static struct dst_entry *tcp_v6_route_req(const struct sock *sk,
 711                                           struct flowi *fl,
 712                                           const struct request_sock *req,
 713                                           bool *strict)
 714 {
 715         if (strict)
 716                 *strict = true;
 717         return inet6_csk_route_req(sk, &fl->u.ip6, req, IPPROTO_TCP);
 718 }
 719
 720 struct request_sock_ops tcp6_request_sock_ops __read_mostly = {
 721         .family         =       AF_INET6,
 722         .obj_size       =       sizeof(struct tcp6_request_sock),
 723         .rtx_syn_ack    =       tcp_rtx_synack,
 724         .send_ack       =       tcp_v6_reqsk_send_ack,
 725         .destructor     =       tcp_v6_reqsk_destructor,
 726         .send_reset     =       tcp_v6_send_reset,
 727         .syn_ack_timeout =      tcp_syn_ack_timeout,
 728 };
 729
 730 static const struct tcp_request_sock_ops tcp_request_sock_ipv6_ops = {
 731         .mss_clamp      =       IPV6_MIN_MTU - sizeof(struct tcphdr) -
 732                                 sizeof(struct ipv6hdr),
 733 #ifdef CONFIG_TCP_MD5SIG
 734         .req_md5_lookup =       tcp_v6_md5_lookup,
 735         .calc_md5_hash  =       tcp_v6_md5_hash_skb,
 736 #endif
 737         .init_req       =       tcp_v6_init_req,
 738 #ifdef CONFIG_SYN_COOKIES
 739         .cookie_init_seq =      cookie_v6_init_sequence,
 740 #endif
 741         .route_req      =       tcp_v6_route_req,
 742         .init_seq       =       tcp_v6_init_sequence,
 743         .send_synack    =       tcp_v6_send_synack,
 744 };
 745
 746 static void tcp_v6_send_response(const struct sock *sk, struct sk_buff *skb, u32 seq,
 747                                  u32 ack, u32 win, u32 tsval, u32 tsecr,
 748                                  int oif, struct tcp_md5sig_key *key, int rst,
 749                                  u8 tclass, __be32 label)
 750 {
 751         const struct tcphdr *th = tcp_hdr(skb);
 752         struct tcphdr *t1;
 753         struct sk_buff *buff;
 754         struct flowi6 fl6;
 755         struct net *net = sk ? sock_net(sk) : dev_net(skb_dst(skb)->dev);
 756         struct sock *ctl_sk = net->ipv6.tcp_sk;
 757         unsigned int tot_len = sizeof(struct tcphdr);
 758         struct dst_entry *dst;
 759         __be32 *topt;
 760
 761         if (tsecr)
 762                 tot_len += TCPOLEN_TSTAMP_ALIGNED;
 763 #ifdef CONFIG_TCP_MD5SIG
 764         if (key)
 765                 tot_len += TCPOLEN_MD5SIG_ALIGNED;
 766 #endif
 767
 768         buff = alloc_skb(MAX_HEADER + sizeof(struct ipv6hdr) + tot_len,
 769                          GFP_ATOMIC);
 770         if (!buff)
 771                 return;
 772
 773         skb_reserve(buff, MAX_HEADER + sizeof(struct ipv6hdr) + tot_len);
 774
 775         t1 = (struct tcphdr *) skb_push(buff, tot_len);
 776         skb_reset_transport_header(buff);
 777
 778         /* Swap the send and the receive. */
 779         memset(t1, 0, sizeof(*t1));
 780         t1->dest = th->source;
 781         t1->source = th->dest;
 782         t1->doff = tot_len / 4;
 783         t1->seq = htonl(seq);
 784         t1->ack_seq = htonl(ack);
 785         t1->ack = !rst || !th->ack;
 786         t1->rst = rst;
 787         t1->window = htons(win);
 788
 789         topt = (__be32 *)(t1 + 1);
 790
 791         if (tsecr) {
 792                 *topt++ = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
 793                                 (TCPOPT_TIMESTAMP << 8) | TCPOLEN_TIMESTAMP);
 794                 *topt++ = htonl(tsval);
 795                 *topt++ = htonl(tsecr);
 796         }
 797
 798 #ifdef CONFIG_TCP_MD5SIG
 799         if (key) {
 800                 *topt++ = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
 801                                 (TCPOPT_MD5SIG << 8) | TCPOLEN_MD5SIG);
 802                 tcp_v6_md5_hash_hdr((__u8 *)topt, key,
 803                                     &ipv6_hdr(skb)->saddr,
 804                                     &ipv6_hdr(skb)->daddr, t1);
 805         }
 806 #endif
 807
 808         memset(&fl6, 0, sizeof(fl6));
 809         fl6.daddr = ipv6_hdr(skb)->saddr;
 810         fl6.saddr = ipv6_hdr(skb)->daddr;
 811         fl6.flowlabel = label;
 812
 813         buff->ip_summed = CHECKSUM_PARTIAL;
 814         buff->csum = 0;
 815
 816         __tcp_v6_send_check(buff, &fl6.saddr, &fl6.daddr);
 817
 818         fl6.flowi6_proto = IPPROTO_TCP;
 819         if (rt6_need_strict(&fl6.daddr) && !oif)
 820                 fl6.flowi6_oif = tcp_v6_iif(skb);
 821         else
 822                 fl6.flowi6_oif = oif ? : skb->skb_iif;
 823
 824         fl6.flowi6_mark = IP6_REPLY_MARK(net, skb->mark);
 825         fl6.fl6_dport = t1->dest;
 826         fl6.fl6_sport = t1->source;
 827         security_skb_classify_flow(skb, flowi6_to_flowi(&fl6));
 828
 829         /* Pass a socket to ip6_dst_lookup either it is for RST
 830          * Underlying function will use this to retrieve the network
 831          * namespace
 832          */
 833         dst = ip6_dst_lookup_flow(ctl_sk, &fl6, NULL);
 834         if (!IS_ERR(dst)) {
 835                 skb_dst_set(buff, dst);
 836                 ip6_xmit(ctl_sk, buff, &fl6, NULL, tclass);
 837                 TCP_INC_STATS(net, TCP_MIB_OUTSEGS);
 838                 if (rst)
 839                         TCP_INC_STATS(net, TCP_MIB_OUTRSTS);
 840                 return;
 841         }
 842
 843         kfree_skb(buff);
 844 }
 845
 846 static void tcp_v6_send_reset(const struct sock *sk, struct sk_buff *skb)
 847 {
 848         const struct tcphdr *th = tcp_hdr(skb);
 849         u32 seq = 0, ack_seq = 0;
 850         struct tcp_md5sig_key *key = NULL;
 851 #ifdef CONFIG_TCP_MD5SIG
 852         const __u8 *hash_location = NULL;
 853         struct ipv6hdr *ipv6h = ipv6_hdr(skb);
 854         unsigned char newhash[16];
 855         int genhash;
 856         struct sock *sk1 = NULL;
 857 #endif
 858         int oif;
 859
 860         if (th->rst)
 861                 return;
 862
 863         /* If sk not NULL, it means we did a successful lookup and incoming
 864          * route had to be correct. prequeue might have dropped our dst.
 865          */
 866         if (!sk && !ipv6_unicast_destination(skb))
 867                 return;
 868
 869 #ifdef CONFIG_TCP_MD5SIG
 870         rcu_read_lock();
 871         hash_location = tcp_parse_md5sig_option(th);
 872         if (sk && sk_fullsock(sk)) {
 873                 key = tcp_v6_md5_do_lookup(sk, &ipv6h->saddr);
 874         } else if (hash_location) {
 875                 /*
 876                  * active side is lost. Try to find listening socket through
 877                  * source port, and then find md5 key through listening socket.
 878                  * we are not loose security here:
 879                  * Incoming packet is checked with md5 hash with finding key,
 880                  * no RST generated if md5 hash doesn't match.
 881                  */
 882                 sk1 = inet6_lookup_listener(dev_net(skb_dst(skb)->dev),
 883                                            &tcp_hashinfo, NULL, 0,
 884                                            &ipv6h->saddr,
 885                                            th->source, &ipv6h->daddr,
 886                                            ntohs(th->source), tcp_v6_iif(skb));
 887                 if (!sk1)
 888                         goto out;
 889
 890                 key = tcp_v6_md5_do_lookup(sk1, &ipv6h->saddr);
 891                 if (!key)
 892                         goto out;
 893
 894                 genhash = tcp_v6_md5_hash_skb(newhash, key, NULL, skb);
 895                 if (genhash || memcmp(hash_location, newhash, 16) != 0)
 896                         goto out;
 897         }
 898 #endif
 899
 900         if (th->ack)
 901                 seq = ntohl(th->ack_seq);
 902         else
 903                 ack_seq = ntohl(th->seq) + th->syn + th->fin + skb->len -
 904                           (th->doff << 2);
 905
 906         oif = sk ? sk->sk_bound_dev_if : 0;
 907         tcp_v6_send_response(sk, skb, seq, ack_seq, 0, 0, 0, oif, key, 1, 0, 0);
 908
 909 #ifdef CONFIG_TCP_MD5SIG
 910 out:
 911         rcu_read_unlock();
 912 #endif
 913 }
 914
 915 static void tcp_v6_send_ack(const struct sock *sk, struct sk_buff *skb, u32 seq,
 916                             u32 ack, u32 win, u32 tsval, u32 tsecr, int oif,
 917                             struct tcp_md5sig_key *key, u8 tclass,
 918                             __be32 label)
 919 {
 920         tcp_v6_send_response(sk, skb, seq, ack, win, tsval, tsecr, oif, key, 0,
 921                              tclass, label);
 922 }
 923
 924 static void tcp_v6_timewait_ack(struct sock *sk, struct sk_buff *skb)
 925 {
 926         struct inet_timewait_sock *tw = inet_twsk(sk);
 927         struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
 928
 929         tcp_v6_send_ack(sk, skb, tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
 930                         tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
 931                         tcp_time_stamp + tcptw->tw_ts_offset,
 932                         tcptw->tw_ts_recent, tw->tw_bound_dev_if, tcp_twsk_md5_key(tcptw),
 933                         tw->tw_tclass, cpu_to_be32(tw->tw_flowlabel));
 934
 935         inet_twsk_put(tw);
 936 }
 937
 938 static void tcp_v6_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb,
 939                                   struct request_sock *req)
 940 {
 941         /* sk->sk_state == TCP_LISTEN -> for regular TCP_SYN_RECV
 942          * sk->sk_state == TCP_SYN_RECV -> for Fast Open.
 943          */
 944         /* RFC 7323 2.3
 945          * The window field (SEG.WND) of every outgoing segment, with the
 946          * exception of <SYN> segments, MUST be right-shifted by
 947          * Rcv.Wind.Shift bits:
 948          */
 949         tcp_v6_send_ack(sk, skb, (sk->sk_state == TCP_LISTEN) ?
 950                         tcp_rsk(req)->snt_isn + 1 : tcp_sk(sk)->snd_nxt,
 951                         tcp_rsk(req)->rcv_nxt,
 952                         req->rsk_rcv_wnd >> inet_rsk(req)->rcv_wscale,
 953                         tcp_time_stamp, req->ts_recent, sk->sk_bound_dev_if,
 954                         tcp_v6_md5_do_lookup(sk, &ipv6_hdr(skb)->daddr),
 955                         0, 0);
 956 }
 957
 958
 959 static struct sock *tcp_v6_cookie_check(struct sock *sk, struct sk_buff *skb)
 960 {
 961 #ifdef CONFIG_SYN_COOKIES
 962         const struct tcphdr *th = tcp_hdr(skb);
 963
 964         if (!th->syn)
 965                 sk = cookie_v6_check(sk, skb);
 966 #endif
 967         return sk;
 968 }
 969
 970 static int tcp_v6_conn_request(struct sock *sk, struct sk_buff *skb)
 971 {
 972         if (skb->protocol == htons(ETH_P_IP))
 973                 return tcp_v4_conn_request(sk, skb);
 974
 975         if (!ipv6_unicast_destination(skb))
 976                 goto drop;
 977
 978         return tcp_conn_request(&tcp6_request_sock_ops,
 979                                 &tcp_request_sock_ipv6_ops, sk, skb);
 980
 981 drop:
 982         tcp_listendrop(sk);
 983         return 0; /* don't send reset */
 984 }
 985
 986 static struct sock *tcp_v6_syn_recv_sock(const struct sock *sk, struct sk_buff *skb,
 987                                          struct request_sock *req,
 988                                          struct dst_entry *dst,
 989                                          struct request_sock *req_unhash,
 990                                          bool *own_req)
 991 {
 992         struct inet_request_sock *ireq;
 993         struct ipv6_pinfo *newnp;
 994         const struct ipv6_pinfo *np = inet6_sk(sk);
 995         struct ipv6_txoptions *opt;
 996         struct tcp6_sock *newtcp6sk;
 997         struct inet_sock *newinet;
 998         struct tcp_sock *newtp;
 999         struct sock *newsk;
1000 #ifdef CONFIG_TCP_MD5SIG
1001         struct tcp_md5sig_key *key;
1002 #endif
1003         struct flowi6 fl6;
1004
1005         if (skb->protocol == htons(ETH_P_IP)) {
1006                 /*
1007                  *      v6 mapped
1008                  */
1009
1010                 newsk = tcp_v4_syn_recv_sock(sk, skb, req, dst,
1011                                              req_unhash, own_req);
1012
1013                 if (!newsk)
1014                         return NULL;
1015
1016                 newtcp6sk = (struct tcp6_sock *)newsk;
1017                 inet_sk(newsk)->pinet6 = &newtcp6sk->inet6;
1018
1019                 newinet = inet_sk(newsk);
1020                 newnp = inet6_sk(newsk);
1021                 newtp = tcp_sk(newsk);
1022
1023                 memcpy(newnp, np, sizeof(struct ipv6_pinfo));
1024
1025                 newnp->saddr = newsk->sk_v6_rcv_saddr;
1026
1027                 inet_csk(newsk)->icsk_af_ops = &ipv6_mapped;
1028                 newsk->sk_backlog_rcv = tcp_v4_do_rcv;
1029 #ifdef CONFIG_TCP_MD5SIG
1030                 newtp->af_specific = &tcp_sock_ipv6_mapped_specific;
1031 #endif
1032
1033                 newnp->ipv6_ac_list = NULL;
1034                 newnp->ipv6_fl_list = NULL;
1035                 newnp->pktoptions  = NULL;
1036                 newnp->opt         = NULL;
1037                 newnp->mcast_oif   = tcp_v6_iif(skb);
1038                 newnp->mcast_hops  = ipv6_hdr(skb)->hop_limit;
1039                 newnp->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(skb));
1040                 if (np->repflow)
1041                         newnp->flow_label = ip6_flowlabel(ipv6_hdr(skb));
1042
1043                 /*
1044                  * No need to charge this sock to the relevant IPv6 refcnt debug socks count
1045                  * here, tcp_create_openreq_child now does this for us, see the comment in
1046                  * that function for the gory details. -acme
1047                  */
1048
1049                 /* It is tricky place. Until this moment IPv4 tcp
1050                    worked with IPv6 icsk.icsk_af_ops.
1051                    Sync it now.
1052                  */
1053                 tcp_sync_mss(newsk, inet_csk(newsk)->icsk_pmtu_cookie);
1054
1055                 return newsk;
1056         }
1057
1058         ireq = inet_rsk(req);
1059
1060         if (sk_acceptq_is_full(sk))
1061                 goto out_overflow;
1062
1063         if (!dst) {
1064                 dst = inet6_csk_route_req(sk, &fl6, req, IPPROTO_TCP);
1065                 if (!dst)
1066                         goto out;
1067         }
1068
1069         newsk = tcp_create_openreq_child(sk, req, skb);
1070         if (!newsk)
1071                 goto out_nonewsk;
1072
1073         /*
1074          * No need to charge this sock to the relevant IPv6 refcnt debug socks
1075          * count here, tcp_create_openreq_child now does this for us, see the
1076          * comment in that function for the gory details. -acme
1077          */
1078
1079         newsk->sk_gso_type = SKB_GSO_TCPV6;
1080         ip6_dst_store(newsk, dst, NULL, NULL);
1081         inet6_sk_rx_dst_set(newsk, skb);
1082
1083         newtcp6sk = (struct tcp6_sock *)newsk;
1084         inet_sk(newsk)->pinet6 = &newtcp6sk->inet6;
1085
1086         newtp = tcp_sk(newsk);
1087         newinet = inet_sk(newsk);
1088         newnp = inet6_sk(newsk);
1089
1090         memcpy(newnp, np, sizeof(struct ipv6_pinfo));
1091
1092         newsk->sk_v6_daddr = ireq->ir_v6_rmt_addr;
1093         newnp->saddr = ireq->ir_v6_loc_addr;
1094         newsk->sk_v6_rcv_saddr = ireq->ir_v6_loc_addr;
1095         newsk->sk_bound_dev_if = ireq->ir_iif;
1096
1097         /* Now IPv6 options...
1098
1099            First: no IPv4 options.
1100          */
1101         newinet->inet_opt = NULL;
1102         newnp->ipv6_ac_list = NULL;
1103         newnp->ipv6_fl_list = NULL;
1104
1105         /* Clone RX bits */
1106         newnp->rxopt.all = np->rxopt.all;
1107
1108         newnp->pktoptions = NULL;
1109         newnp->opt        = NULL;
1110         newnp->mcast_oif  = tcp_v6_iif(skb);
1111         newnp->mcast_hops = ipv6_hdr(skb)->hop_limit;
1112         newnp->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(skb));
1113         if (np->repflow)
1114                 newnp->flow_label = ip6_flowlabel(ipv6_hdr(skb));
1115
1116         /* Clone native IPv6 options from listening socket (if any)
1117
1118            Yes, keeping reference count would be much more clever,
1119            but we make one more one thing there: reattach optmem
1120            to newsk.
1121          */
1122         opt = ireq->ipv6_opt;
1123         if (!opt)
1124                 opt = rcu_dereference(np->opt);
1125         if (opt) {
1126                 opt = ipv6_dup_options(newsk, opt);
1127                 RCU_INIT_POINTER(newnp->opt, opt);
1128         }
1129         inet_csk(newsk)->icsk_ext_hdr_len = 0;
1130         if (opt)
1131                 inet_csk(newsk)->icsk_ext_hdr_len = opt->opt_nflen +
1132                                                     opt->opt_flen;
1133
1134         tcp_ca_openreq_child(newsk, dst);
1135
1136         tcp_sync_mss(newsk, dst_mtu(dst));
1137         newtp->advmss = dst_metric_advmss(dst);
1138         if (tcp_sk(sk)->rx_opt.user_mss &&
1139             tcp_sk(sk)->rx_opt.user_mss < newtp->advmss)
1140                 newtp->advmss = tcp_sk(sk)->rx_opt.user_mss;
1141
1142         tcp_initialize_rcv_mss(newsk);
1143
1144         newinet->inet_daddr = newinet->inet_saddr = LOOPBACK4_IPV6;
1145         newinet->inet_rcv_saddr = LOOPBACK4_IPV6;
1146
1147 #ifdef CONFIG_TCP_MD5SIG
1148         /* Copy over the MD5 key from the original socket */
1149         key = tcp_v6_md5_do_lookup(sk, &newsk->sk_v6_daddr);
1150         if (key) {
1151                 /* We're using one, so create a matching key
1152                  * on the newsk structure. If we fail to get
1153                  * memory, then we end up not copying the key
1154                  * across. Shucks.
1155                  */
1156                 tcp_md5_do_add(newsk, (union tcp_md5_addr *)&newsk->sk_v6_daddr,
1157                                AF_INET6, key->key, key->keylen,
1158                                sk_gfp_mask(sk, GFP_ATOMIC));
1159         }
1160 #endif
1161
1162         if (__inet_inherit_port(sk, newsk) < 0) {
1163                 inet_csk_prepare_forced_close(newsk);
1164                 tcp_done(newsk);
1165                 goto out;
1166         }
1167         *own_req = inet_ehash_nolisten(newsk, req_to_sk(req_unhash));
1168         if (*own_req) {
1169                 tcp_move_syn(newtp, req);
1170
1171                 /* Clone pktoptions received with SYN, if we own the req */
1172                 if (ireq->pktopts) {
1173                         newnp->pktoptions = skb_clone(ireq->pktopts,
1174                                                       sk_gfp_mask(sk, GFP_ATOMIC));
1175                         consume_skb(ireq->pktopts);
1176                         ireq->pktopts = NULL;
1177                         if (newnp->pktoptions)
1178                                 skb_set_owner_r(newnp->pktoptions, newsk);
1179                 }
1180         }
1181
1182         return newsk;
1183
1184 out_overflow:
1185         __NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
1186 out_nonewsk:
1187         dst_release(dst);
1188 out:
1189         tcp_listendrop(sk);
1190         return NULL;
1191 }
1192
1193 /* The socket must have it's spinlock held when we get
1194  * here, unless it is a TCP_LISTEN socket.
1195  *
1196  * We have a potential double-lock case here, so even when
1197  * doing backlog processing we use the BH locking scheme.
1198  * This is because we cannot sleep with the original spinlock
1199  * held.
1200  */
1201 static int tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb)
1202 {
1203         struct ipv6_pinfo *np = inet6_sk(sk);
1204         struct tcp_sock *tp;
1205         struct sk_buff *opt_skb = NULL;
1206
1207         /* Imagine: socket is IPv6. IPv4 packet arrives,
1208            goes to IPv4 receive handler and backlogged.
1209            From backlog it always goes here. Kerboom...
1210            Fortunately, tcp_rcv_established and rcv_established
1211            handle them correctly, but it is not case with
1212            tcp_v6_hnd_req and tcp_v6_send_reset().   --ANK
1213          */
1214
1215         if (skb->protocol == htons(ETH_P_IP))
1216                 return tcp_v4_do_rcv(sk, skb);
1217
1218         if (sk_filter(sk, skb))
1219                 goto discard;
1220
1221         /*
1222          *      socket locking is here for SMP purposes as backlog rcv
1223          *      is currently called with bh processing disabled.
1224          */
1225
1226         /* Do Stevens' IPV6_PKTOPTIONS.
1227
1228            Yes, guys, it is the only place in our code, where we
1229            may make it not affecting IPv4.
1230            The rest of code is protocol independent,
1231            and I do not like idea to uglify IPv4.
1232
1233            Actually, all the idea behind IPV6_PKTOPTIONS
1234            looks not very well thought. For now we latch
1235            options, received in the last packet, enqueued
1236            by tcp. Feel free to propose better solution.
1237                                                --ANK (980728)
1238          */
1239         if (np->rxopt.all)
1240                 opt_skb = skb_clone(skb, sk_gfp_mask(sk, GFP_ATOMIC));
1241
1242         if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
1243                 struct dst_entry *dst = sk->sk_rx_dst;
1244
1245                 sock_rps_save_rxhash(sk, skb);
1246                 sk_mark_napi_id(sk, skb);
1247                 if (dst) {
1248                         if (inet_sk(sk)->rx_dst_ifindex != skb->skb_iif ||
1249                             dst->ops->check(dst, np->rx_dst_cookie) == NULL) {
1250                                 dst_release(dst);
1251                                 sk->sk_rx_dst = NULL;
1252                         }
1253                 }
1254
1255                 tcp_rcv_established(sk, skb, tcp_hdr(skb), skb->len);
1256                 if (opt_skb)
1257                         goto ipv6_pktoptions;
1258                 return 0;
1259         }
1260
1261         if (tcp_checksum_complete(skb))
1262                 goto csum_err;
1263
1264         if (sk->sk_state == TCP_LISTEN) {
1265                 struct sock *nsk = tcp_v6_cookie_check(sk, skb);
1266
1267                 if (!nsk)
1268                         goto discard;
1269
1270                 if (nsk != sk) {
1271                         sock_rps_save_rxhash(nsk, skb);
1272                         sk_mark_napi_id(nsk, skb);
1273                         if (tcp_child_process(sk, nsk, skb))
1274                                 goto reset;
1275                         if (opt_skb)
1276                                 __kfree_skb(opt_skb);
1277                         return 0;
1278                 }
1279         } else
1280                 sock_rps_save_rxhash(sk, skb);
1281
1282         if (tcp_rcv_state_process(sk, skb))
1283                 goto reset;
1284         if (opt_skb)
1285                 goto ipv6_pktoptions;
1286         return 0;
1287
1288 reset:
1289         tcp_v6_send_reset(sk, skb);
1290 discard:
1291         if (opt_skb)
1292                 __kfree_skb(opt_skb);
1293         kfree_skb(skb);
1294         return 0;
1295 csum_err:
1296         TCP_INC_STATS(sock_net(sk), TCP_MIB_CSUMERRORS);
1297         TCP_INC_STATS(sock_net(sk), TCP_MIB_INERRS);
1298         goto discard;
1299
1300
1301 ipv6_pktoptions:
1302         /* Do you ask, what is it?
1303
1304            1. skb was enqueued by tcp.
1305            2. skb is added to tail of read queue, rather than out of order.
1306            3. socket is not in passive state.
1307            4. Finally, it really contains options, which user wants to receive.
1308          */
1309         tp = tcp_sk(sk);
1310         if (TCP_SKB_CB(opt_skb)->end_seq == tp->rcv_nxt &&
1311             !((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN))) {
1312                 if (np->rxopt.bits.rxinfo || np->rxopt.bits.rxoinfo)
1313                         np->mcast_oif = tcp_v6_iif(opt_skb);
1314                 if (np->rxopt.bits.rxhlim || np->rxopt.bits.rxohlim)
1315                         np->mcast_hops = ipv6_hdr(opt_skb)->hop_limit;
1316                 if (np->rxopt.bits.rxflow || np->rxopt.bits.rxtclass)
1317                         np->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(opt_skb));
1318                 if (np->repflow)
1319                         np->flow_label = ip6_flowlabel(ipv6_hdr(opt_skb));
1320                 if (ipv6_opt_accepted(sk, opt_skb, &TCP_SKB_CB(opt_skb)->header.h6)) {
1321                         skb_set_owner_r(opt_skb, sk);
1322                         opt_skb = xchg(&np->pktoptions, opt_skb);
1323                 } else {
1324                         __kfree_skb(opt_skb);
1325                         opt_skb = xchg(&np->pktoptions, NULL);
1326                 }
1327         }
1328
1329         kfree_skb(opt_skb);
1330         return 0;
1331 }
1332
1333 static void tcp_v6_fill_cb(struct sk_buff *skb, const struct ipv6hdr *hdr,
1334                            const struct tcphdr *th)
1335 {
1336         /* This is tricky: we move IP6CB at its correct location into
1337          * TCP_SKB_CB(). It must be done after xfrm6_policy_check(), because
1338          * _decode_session6() uses IP6CB().
1339          * barrier() makes sure compiler won't play aliasing games.
1340          */
1341         memmove(&TCP_SKB_CB(skb)->header.h6, IP6CB(skb),
1342                 sizeof(struct inet6_skb_parm));
1343         barrier();
1344
1345         TCP_SKB_CB(skb)->seq = ntohl(th->seq);
1346         TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
1347                                     skb->len - th->doff*4);
1348         TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
1349         TCP_SKB_CB(skb)->tcp_flags = tcp_flag_byte(th);
1350         TCP_SKB_CB(skb)->tcp_tw_isn = 0;
1351         TCP_SKB_CB(skb)->ip_dsfield = ipv6_get_dsfield(hdr);
1352         TCP_SKB_CB(skb)->sacked = 0;
1353 }
1354
1355 static void tcp_v6_restore_cb(struct sk_buff *skb)
1356 {
1357         /* We need to move header back to the beginning if xfrm6_policy_check()
1358          * and tcp_v6_fill_cb() are going to be called again.
1359          */
1360         memmove(IP6CB(skb), &TCP_SKB_CB(skb)->header.h6,
1361                 sizeof(struct inet6_skb_parm));
1362 }
1363
1364 static int tcp_v6_rcv(struct sk_buff *skb)
1365 {
1366         const struct tcphdr *th;
1367         const struct ipv6hdr *hdr;
1368         bool refcounted;
1369         struct sock *sk;
1370         int ret;
1371         struct net *net = dev_net(skb->dev);
1372
1373         if (skb->pkt_type != PACKET_HOST)
1374                 goto discard_it;
1375
1376         /*
1377          *      Count it even if it's bad.
1378          */
1379         __TCP_INC_STATS(net, TCP_MIB_INSEGS);
1380
1381         if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
1382                 goto discard_it;
1383
1384         th = (const struct tcphdr *)skb->data;
1385
1386         if (unlikely(th->doff < sizeof(struct tcphdr)/4))
1387                 goto bad_packet;
1388         if (!pskb_may_pull(skb, th->doff*4))
1389                 goto discard_it;
1390
1391         if (skb_checksum_init(skb, IPPROTO_TCP, ip6_compute_pseudo))
1392                 goto csum_error;
1393
1394         th = (const struct tcphdr *)skb->data;
1395         hdr = ipv6_hdr(skb);
1396
1397 lookup:
1398         sk = __inet6_lookup_skb(&tcp_hashinfo, skb, __tcp_hdrlen(th),
1399                                 th->source, th->dest, inet6_iif(skb),
1400                                 &refcounted);
1401         if (!sk)
1402                 goto no_tcp_socket;
1403
1404 process:
1405         if (sk->sk_state == TCP_TIME_WAIT)
1406                 goto do_time_wait;
1407
1408         if (sk->sk_state == TCP_NEW_SYN_RECV) {
1409                 struct request_sock *req = inet_reqsk(sk);
1410                 struct sock *nsk;
1411
1412                 sk = req->rsk_listener;
1413                 tcp_v6_fill_cb(skb, hdr, th);
1414                 if (tcp_v6_inbound_md5_hash(sk, skb)) {
1415                         sk_drops_add(sk, skb);
1416                         reqsk_put(req);
1417                         goto discard_it;
1418                 }
1419                 if (unlikely(sk->sk_state != TCP_LISTEN)) {
1420                         inet_csk_reqsk_queue_drop_and_put(sk, req);
1421                         goto lookup;
1422                 }
1423                 sock_hold(sk);
1424                 refcounted = true;
1425                 nsk = tcp_check_req(sk, skb, req, false);
1426                 if (!nsk) {
1427                         reqsk_put(req);
1428                         goto discard_and_relse;
1429                 }
1430                 if (nsk == sk) {
1431                         reqsk_put(req);
1432                         tcp_v6_restore_cb(skb);
1433                 } else if (tcp_child_process(sk, nsk, skb)) {
1434                         tcp_v6_send_reset(nsk, skb);
1435                         goto discard_and_relse;
1436                 } else {
1437                         sock_put(sk);
1438                         return 0;
1439                 }
1440         }
1441         if (hdr->hop_limit < inet6_sk(sk)->min_hopcount) {
1442                 __NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP);
1443                 goto discard_and_relse;
1444         }
1445
1446         if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb))
1447                 goto discard_and_relse;
1448
1449         tcp_v6_fill_cb(skb, hdr, th);
1450
1451         if (tcp_v6_inbound_md5_hash(sk, skb))
1452                 goto discard_and_relse;
1453
1454         if (sk_filter(sk, skb))
1455                 goto discard_and_relse;
1456
1457         skb->dev = NULL;
1458
1459         if (sk->sk_state == TCP_LISTEN) {
1460                 ret = tcp_v6_do_rcv(sk, skb);
1461                 goto put_and_return;
1462         }
1463
1464         sk_incoming_cpu_update(sk);
1465
1466         bh_lock_sock_nested(sk);
1467         tcp_segs_in(tcp_sk(sk), skb);
1468         ret = 0;
1469         if (!sock_owned_by_user(sk)) {
1470                 if (!tcp_prequeue(sk, skb))
1471                         ret = tcp_v6_do_rcv(sk, skb);
1472         } else if (tcp_add_backlog(sk, skb)) {
1473                 goto discard_and_relse;
1474         }
1475         bh_unlock_sock(sk);
1476
1477 put_and_return:
1478         if (refcounted)
1479                 sock_put(sk);
1480         return ret ? -1 : 0;
1481
1482 no_tcp_socket:
1483         if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb))
1484                 goto discard_it;
1485
1486         tcp_v6_fill_cb(skb, hdr, th);
1487
1488         if (tcp_checksum_complete(skb)) {
1489 csum_error:
1490                 __TCP_INC_STATS(net, TCP_MIB_CSUMERRORS);
1491 bad_packet:
1492                 __TCP_INC_STATS(net, TCP_MIB_INERRS);
1493         } else {
1494                 tcp_v6_send_reset(NULL, skb);
1495         }
1496
1497 discard_it:
1498         kfree_skb(skb);
1499         return 0;
1500
1501 discard_and_relse:
1502         sk_drops_add(sk, skb);
1503         if (refcounted)
1504                 sock_put(sk);
1505         goto discard_it;
1506
1507 do_time_wait:
1508         if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
1509                 inet_twsk_put(inet_twsk(sk));
1510                 goto discard_it;
1511         }
1512
1513         tcp_v6_fill_cb(skb, hdr, th);
1514
1515         if (tcp_checksum_complete(skb)) {
1516                 inet_twsk_put(inet_twsk(sk));
1517                 goto csum_error;
1518         }
1519
1520         switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) {
1521         case TCP_TW_SYN:
1522         {
1523                 struct sock *sk2;
1524
1525                 sk2 = inet6_lookup_listener(dev_net(skb->dev), &tcp_hashinfo,
1526                                             skb, __tcp_hdrlen(th),
1527                                             &ipv6_hdr(skb)->saddr, th->source,
1528                                             &ipv6_hdr(skb)->daddr,
1529                                             ntohs(th->dest), tcp_v6_iif(skb));
1530                 if (sk2) {
1531                         struct inet_timewait_sock *tw = inet_twsk(sk);
1532                         inet_twsk_deschedule_put(tw);
1533                         sk = sk2;
1534                         tcp_v6_restore_cb(skb);
1535                         refcounted = false;
1536                         goto process;
1537                 }
1538                 /* Fall through to ACK */
1539         }
1540         case TCP_TW_ACK:
1541                 tcp_v6_timewait_ack(sk, skb);
1542                 break;
1543         case TCP_TW_RST:
1544                 tcp_v6_restore_cb(skb);
1545                 tcp_v6_send_reset(sk, skb);
1546                 inet_twsk_deschedule_put(inet_twsk(sk));
1547                 goto discard_it;
1548         case TCP_TW_SUCCESS:
1549                 ;
1550         }
1551         goto discard_it;
1552 }
1553
1554 static void tcp_v6_early_demux(struct sk_buff *skb)
1555 {
1556         const struct ipv6hdr *hdr;
1557         const struct tcphdr *th;
1558         struct sock *sk;
1559
1560         if (skb->pkt_type != PACKET_HOST)
1561                 return;
1562
1563         if (!pskb_may_pull(skb, skb_transport_offset(skb) + sizeof(struct tcphdr)))
1564                 return;
1565
1566         hdr = ipv6_hdr(skb);
1567         th = tcp_hdr(skb);
1568
1569         if (th->doff < sizeof(struct tcphdr) / 4)
1570                 return;
1571
1572         /* Note : We use inet6_iif() here, not tcp_v6_iif() */
1573         sk = __inet6_lookup_established(dev_net(skb->dev), &tcp_hashinfo,
1574                                         &hdr->saddr, th->source,
1575                                         &hdr->daddr, ntohs(th->dest),
1576                                         inet6_iif(skb));
1577         if (sk) {
1578                 skb->sk = sk;
1579                 skb->destructor = sock_edemux;
1580                 if (sk_fullsock(sk)) {
1581                         struct dst_entry *dst = READ_ONCE(sk->sk_rx_dst);
1582
1583                         if (dst)
1584                                 dst = dst_check(dst, inet6_sk(sk)->rx_dst_cookie);
1585                         if (dst &&
1586                             inet_sk(sk)->rx_dst_ifindex == skb->skb_iif)
1587                                 skb_dst_set_noref(skb, dst);
1588                 }
1589         }
1590 }
1591
1592 static struct timewait_sock_ops tcp6_timewait_sock_ops = {
1593         .twsk_obj_size  = sizeof(struct tcp6_timewait_sock),
1594         .twsk_unique    = tcp_twsk_unique,
1595         .twsk_destructor = tcp_twsk_destructor,
1596 };
1597
1598 static const struct inet_connection_sock_af_ops ipv6_specific = {
1599         .queue_xmit        = inet6_csk_xmit,
1600         .send_check        = tcp_v6_send_check,
1601         .rebuild_header    = inet6_sk_rebuild_header,
1602         .sk_rx_dst_set     = inet6_sk_rx_dst_set,
1603         .conn_request      = tcp_v6_conn_request,
1604         .syn_recv_sock     = tcp_v6_syn_recv_sock,
1605         .net_header_len    = sizeof(struct ipv6hdr),
1606         .net_frag_header_len = sizeof(struct frag_hdr),
1607         .setsockopt        = ipv6_setsockopt,
1608         .getsockopt        = ipv6_getsockopt,
1609         .addr2sockaddr     = inet6_csk_addr2sockaddr,
1610         .sockaddr_len      = sizeof(struct sockaddr_in6),
1611         .bind_conflict     = inet6_csk_bind_conflict,
1612 #ifdef CONFIG_COMPAT
1613         .compat_setsockopt = compat_ipv6_setsockopt,
1614         .compat_getsockopt = compat_ipv6_getsockopt,
1615 #endif
1616         .mtu_reduced       = tcp_v6_mtu_reduced,
1617 };
1618
1619 #ifdef CONFIG_TCP_MD5SIG
1620 static const struct tcp_sock_af_ops tcp_sock_ipv6_specific = {
1621         .md5_lookup     =       tcp_v6_md5_lookup,
1622         .calc_md5_hash  =       tcp_v6_md5_hash_skb,
1623         .md5_parse      =       tcp_v6_parse_md5_keys,
1624 };
1625 #endif
1626
1627 /*
1628  *      TCP over IPv4 via INET6 API
1629  */
1630 static const struct inet_connection_sock_af_ops ipv6_mapped = {
1631         .queue_xmit        = ip_queue_xmit,
1632         .send_check        = tcp_v4_send_check,
1633         .rebuild_header    = inet_sk_rebuild_header,
1634         .sk_rx_dst_set     = inet_sk_rx_dst_set,
1635         .conn_request      = tcp_v6_conn_request,
1636         .syn_recv_sock     = tcp_v6_syn_recv_sock,
1637         .net_header_len    = sizeof(struct iphdr),
1638         .setsockopt        = ipv6_setsockopt,
1639         .getsockopt        = ipv6_getsockopt,
1640         .addr2sockaddr     = inet6_csk_addr2sockaddr,
1641         .sockaddr_len      = sizeof(struct sockaddr_in6),
1642         .bind_conflict     = inet6_csk_bind_conflict,
1643 #ifdef CONFIG_COMPAT
1644         .compat_setsockopt = compat_ipv6_setsockopt,
1645         .compat_getsockopt = compat_ipv6_getsockopt,
1646 #endif
1647         .mtu_reduced       = tcp_v4_mtu_reduced,
1648 };
1649
1650 #ifdef CONFIG_TCP_MD5SIG
1651 static const struct tcp_sock_af_ops tcp_sock_ipv6_mapped_specific = {
1652         .md5_lookup     =       tcp_v4_md5_lookup,
1653         .calc_md5_hash  =       tcp_v4_md5_hash_skb,
1654         .md5_parse      =       tcp_v6_parse_md5_keys,
1655 };
1656 #endif
1657
1658 /* NOTE: A lot of things set to zero explicitly by call to
1659  *       sk_alloc() so need not be done here.
1660  */
1661 static int tcp_v6_init_sock(struct sock *sk)
1662 {
1663         struct inet_connection_sock *icsk = inet_csk(sk);
1664
1665         tcp_init_sock(sk);
1666
1667         icsk->icsk_af_ops = &ipv6_specific;
1668
1669 #ifdef CONFIG_TCP_MD5SIG
1670         tcp_sk(sk)->af_specific = &tcp_sock_ipv6_specific;
1671 #endif
1672
1673         return 0;
1674 }
1675
1676 static void tcp_v6_destroy_sock(struct sock *sk)
1677 {
1678         tcp_v4_destroy_sock(sk);
1679         inet6_destroy_sock(sk);
1680 }
1681
1682 #ifdef CONFIG_PROC_FS
1683 /* Proc filesystem TCPv6 sock list dumping. */
1684 static void get_openreq6(struct seq_file *seq,
1685                          const struct request_sock *req, int i)
1686 {
1687         long ttd = req->rsk_timer.expires - jiffies;
1688         const struct in6_addr *src = &inet_rsk(req)->ir_v6_loc_addr;
1689         const struct in6_addr *dest = &inet_rsk(req)->ir_v6_rmt_addr;
1690
1691         if (ttd < 0)
1692                 ttd = 0;
1693
1694         seq_printf(seq,
1695                    "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
1696                    "%02X %08X:%08X %02X:%08lX %08X %5u %8d %d %d %pK\n",
1697                    i,
1698                    src->s6_addr32[0], src->s6_addr32[1],
1699                    src->s6_addr32[2], src->s6_addr32[3],
1700                    inet_rsk(req)->ir_num,
1701                    dest->s6_addr32[0], dest->s6_addr32[1],
1702                    dest->s6_addr32[2], dest->s6_addr32[3],
1703                    ntohs(inet_rsk(req)->ir_rmt_port),
1704                    TCP_SYN_RECV,
1705                    0, 0, /* could print option size, but that is af dependent. */
1706                    1,   /* timers active (only the expire timer) */
1707                    jiffies_to_clock_t(ttd),
1708                    req->num_timeout,
1709                    from_kuid_munged(seq_user_ns(seq),
1710                                     sock_i_uid(req->rsk_listener)),
1711                    0,  /* non standard timer */
1712                    0, /* open_requests have no inode */
1713                    0, req);
1714 }
1715
1716 static void get_tcp6_sock(struct seq_file *seq, struct sock *sp, int i)
1717 {
1718         const struct in6_addr *dest, *src;
1719         __u16 destp, srcp;
1720         int timer_active;
1721         unsigned long timer_expires;
1722         const struct inet_sock *inet = inet_sk(sp);
1723         const struct tcp_sock *tp = tcp_sk(sp);
1724         const struct inet_connection_sock *icsk = inet_csk(sp);
1725         const struct fastopen_queue *fastopenq = &icsk->icsk_accept_queue.fastopenq;
1726         int rx_queue;
1727         int state;
1728
1729         dest  = &sp->sk_v6_daddr;
1730         src   = &sp->sk_v6_rcv_saddr;
1731         destp = ntohs(inet->inet_dport);
1732         srcp  = ntohs(inet->inet_sport);
1733
1734         if (icsk->icsk_pending == ICSK_TIME_RETRANS ||
1735             icsk->icsk_pending == ICSK_TIME_EARLY_RETRANS ||
1736             icsk->icsk_pending == ICSK_TIME_LOSS_PROBE) {
1737                 timer_active    = 1;
1738                 timer_expires   = icsk->icsk_timeout;
1739         } else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
1740                 timer_active    = 4;
1741                 timer_expires   = icsk->icsk_timeout;
1742         } else if (timer_pending(&sp->sk_timer)) {
1743                 timer_active    = 2;
1744                 timer_expires   = sp->sk_timer.expires;
1745         } else {
1746                 timer_active    = 0;
1747                 timer_expires = jiffies;
1748         }
1749
1750         state = sk_state_load(sp);
1751         if (state == TCP_LISTEN)
1752                 rx_queue = sp->sk_ack_backlog;
1753         else
1754                 /* Because we don't lock the socket,
1755                  * we might find a transient negative value.
1756                  */
1757                 rx_queue = max_t(int, tp->rcv_nxt - tp->copied_seq, 0);
1758
1759         seq_printf(seq,
1760                    "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
1761                    "%02X %08X:%08X %02X:%08lX %08X %5u %8d %lu %d %pK %lu %lu %u %u %d\n",
1762                    i,
1763                    src->s6_addr32[0], src->s6_addr32[1],
1764                    src->s6_addr32[2], src->s6_addr32[3], srcp,
1765                    dest->s6_addr32[0], dest->s6_addr32[1],
1766                    dest->s6_addr32[2], dest->s6_addr32[3], destp,
1767                    state,
1768                    tp->write_seq - tp->snd_una,
1769                    rx_queue,
1770                    timer_active,
1771                    jiffies_delta_to_clock_t(timer_expires - jiffies),
1772                    icsk->icsk_retransmits,
1773                    from_kuid_munged(seq_user_ns(seq), sock_i_uid(sp)),
1774                    icsk->icsk_probes_out,
1775                    sock_i_ino(sp),
1776                    atomic_read(&sp->sk_refcnt), sp,
1777                    jiffies_to_clock_t(icsk->icsk_rto),
1778                    jiffies_to_clock_t(icsk->icsk_ack.ato),
1779                    (icsk->icsk_ack.quick << 1) | icsk->icsk_ack.pingpong,
1780                    tp->snd_cwnd,
1781                    state == TCP_LISTEN ?
1782                         fastopenq->max_qlen :
1783                         (tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh)
1784                    );
1785 }
1786
1787 static void get_timewait6_sock(struct seq_file *seq,
1788                                struct inet_timewait_sock *tw, int i)
1789 {
1790         long delta = tw->tw_timer.expires - jiffies;
1791         const struct in6_addr *dest, *src;
1792         __u16 destp, srcp;
1793
1794         dest = &tw->tw_v6_daddr;
1795         src  = &tw->tw_v6_rcv_saddr;
1796         destp = ntohs(tw->tw_dport);
1797         srcp  = ntohs(tw->tw_sport);
1798
1799         seq_printf(seq,
1800                    "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
1801                    "%02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK\n",
1802                    i,
1803                    src->s6_addr32[0], src->s6_addr32[1],
1804                    src->s6_addr32[2], src->s6_addr32[3], srcp,
1805                    dest->s6_addr32[0], dest->s6_addr32[1],
1806                    dest->s6_addr32[2], dest->s6_addr32[3], destp,
1807                    tw->tw_substate, 0, 0,
1808                    3, jiffies_delta_to_clock_t(delta), 0, 0, 0, 0,
1809                    atomic_read(&tw->tw_refcnt), tw);
1810 }
1811
1812 static int tcp6_seq_show(struct seq_file *seq, void *v)
1813 {
1814         struct tcp_iter_state *st;
1815         struct sock *sk = v;
1816
1817         if (v == SEQ_START_TOKEN) {
1818                 seq_puts(seq,
1819                          "  sl  "
1820                          "local_address                         "
1821                          "remote_address                        "
1822                          "st tx_queue rx_queue tr tm->when retrnsmt"
1823                          "   uid  timeout inode\n");
1824                 goto out;
1825         }
1826         st = seq->private;
1827
1828         if (sk->sk_state == TCP_TIME_WAIT)
1829                 get_timewait6_sock(seq, v, st->num);
1830         else if (sk->sk_state == TCP_NEW_SYN_RECV)
1831                 get_openreq6(seq, v, st->num);
1832         else
1833                 get_tcp6_sock(seq, v, st->num);
1834 out:
1835         return 0;
1836 }
1837
1838 static const struct file_operations tcp6_afinfo_seq_fops = {
1839         .owner   = THIS_MODULE,
1840         .open    = tcp_seq_open,
1841         .read    = seq_read,
1842         .llseek  = seq_lseek,
1843         .release = seq_release_net
1844 };
1845
1846 static struct tcp_seq_afinfo tcp6_seq_afinfo = {
1847         .name           = "tcp6",
1848         .family         = AF_INET6,
1849         .seq_fops       = &tcp6_afinfo_seq_fops,
1850         .seq_ops        = {
1851                 .show           = tcp6_seq_show,
1852         },
1853 };
1854
1855 int __net_init tcp6_proc_init(struct net *net)
1856 {
1857         return tcp_proc_register(net, &tcp6_seq_afinfo);
1858 }
1859
1860 void tcp6_proc_exit(struct net *net)
1861 {
1862         tcp_proc_unregister(net, &tcp6_seq_afinfo);
1863 }
1864 #endif
1865
1866 struct proto tcpv6_prot = {
1867         .name                   = "TCPv6",
1868         .owner                  = THIS_MODULE,
1869         .close                  = tcp_close,
1870         .connect                = tcp_v6_connect,
1871         .disconnect             = tcp_disconnect,
1872         .accept                 = inet_csk_accept,
1873         .ioctl                  = tcp_ioctl,
1874         .init                   = tcp_v6_init_sock,
1875         .destroy                = tcp_v6_destroy_sock,
1876         .shutdown               = tcp_shutdown,
1877         .setsockopt             = tcp_setsockopt,
1878         .getsockopt             = tcp_getsockopt,
1879         .recvmsg                = tcp_recvmsg,
1880         .sendmsg                = tcp_sendmsg,
1881         .sendpage               = tcp_sendpage,
1882         .backlog_rcv            = tcp_v6_do_rcv,
1883         .release_cb             = tcp_release_cb,
1884         .hash                   = inet6_hash,
1885         .unhash                 = inet_unhash,
1886         .get_port               = inet_csk_get_port,
1887         .enter_memory_pressure  = tcp_enter_memory_pressure,
1888         .stream_memory_free     = tcp_stream_memory_free,
1889         .sockets_allocated      = &tcp_sockets_allocated,
1890         .memory_allocated       = &tcp_memory_allocated,
1891         .memory_pressure        = &tcp_memory_pressure,
1892         .orphan_count           = &tcp_orphan_count,
1893         .sysctl_mem             = sysctl_tcp_mem,
1894         .sysctl_wmem            = sysctl_tcp_wmem,
1895         .sysctl_rmem            = sysctl_tcp_rmem,
1896         .max_header             = MAX_TCP_HEADER,
1897         .obj_size               = sizeof(struct tcp6_sock),
1898         .slab_flags             = SLAB_DESTROY_BY_RCU,
1899         .twsk_prot              = &tcp6_timewait_sock_ops,
1900         .rsk_prot               = &tcp6_request_sock_ops,
1901         .h.hashinfo             = &tcp_hashinfo,
1902         .no_autobind            = true,
1903 #ifdef CONFIG_COMPAT
1904         .compat_setsockopt      = compat_tcp_setsockopt,
1905         .compat_getsockopt      = compat_tcp_getsockopt,
1906 #endif
1907         .diag_destroy           = tcp_abort,
1908 };
1909
1910 static const struct inet6_protocol tcpv6_protocol = {
1911         .early_demux    =       tcp_v6_early_demux,
1912         .handler        =       tcp_v6_rcv,
1913         .err_handler    =       tcp_v6_err,
1914         .flags          =       INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
1915 };
1916
1917 static struct inet_protosw tcpv6_protosw = {
1918         .type           =       SOCK_STREAM,
1919         .protocol       =       IPPROTO_TCP,
1920         .prot           =       &tcpv6_prot,
1921         .ops            =       &inet6_stream_ops,
1922         .flags          =       INET_PROTOSW_PERMANENT |
1923                                 INET_PROTOSW_ICSK,
1924 };
1925
1926 static int __net_init tcpv6_net_init(struct net *net)
1927 {
1928         return inet_ctl_sock_create(&net->ipv6.tcp_sk, PF_INET6,
1929                                     SOCK_RAW, IPPROTO_TCP, net);
1930 }
1931
1932 static void __net_exit tcpv6_net_exit(struct net *net)
1933 {
1934         inet_ctl_sock_destroy(net->ipv6.tcp_sk);
1935 }
1936
1937 static void __net_exit tcpv6_net_exit_batch(struct list_head *net_exit_list)
1938 {
1939         inet_twsk_purge(&tcp_hashinfo, &tcp_death_row, AF_INET6);
1940 }
1941
1942 static struct pernet_operations tcpv6_net_ops = {
1943         .init       = tcpv6_net_init,
1944         .exit       = tcpv6_net_exit,
1945         .exit_batch = tcpv6_net_exit_batch,
1946 };
1947
1948 int __init tcpv6_init(void)
1949 {
1950         int ret;
1951
1952         ret = inet6_add_protocol(&tcpv6_protocol, IPPROTO_TCP);
1953         if (ret)
1954                 goto out;
1955
1956         /* register inet6 protocol */
1957         ret = inet6_register_protosw(&tcpv6_protosw);
1958         if (ret)
1959                 goto out_tcpv6_protocol;
1960
1961         ret = register_pernet_subsys(&tcpv6_net_ops);
1962         if (ret)
1963                 goto out_tcpv6_protosw;
1964 out:
1965         return ret;
1966
1967 out_tcpv6_protosw:
1968         inet6_unregister_protosw(&tcpv6_protosw);
1969 out_tcpv6_protocol:
1970         inet6_del_protocol(&tcpv6_protocol, IPPROTO_TCP);
1971         goto out;
1972 }
1973
1974 void tcpv6_exit(void)
1975 {
1976         unregister_pernet_subsys(&tcpv6_net_ops);
1977         inet6_unregister_protosw(&tcpv6_protosw);
1978         inet6_del_protocol(&tcpv6_protocol, IPPROTO_TCP);
1979 }