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/tcp_memcontrol.h>
  65 #include <net/busy_poll.h>
  66
  67 #include <linux/proc_fs.h>
  68 #include <linux/seq_file.h>
  69
  70 #include <linux/crypto.h>
  71 #include <linux/scatterlist.h>
  72
  73 static void     tcp_v6_send_reset(const struct sock *sk, struct sk_buff *skb);
  74 static void     tcp_v6_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb,
  75                                       struct request_sock *req);
  76
  77 static int      tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb);
  78
  79 static const struct inet_connection_sock_af_ops ipv6_mapped;
  80 static const struct inet_connection_sock_af_ops ipv6_specific;
  81 #ifdef CONFIG_TCP_MD5SIG
  82 static const struct tcp_sock_af_ops tcp_sock_ipv6_specific;
  83 static const struct tcp_sock_af_ops tcp_sock_ipv6_mapped_specific;
  84 #else
  85 static struct tcp_md5sig_key *tcp_v6_md5_do_lookup(const struct sock *sk,
  86                                                    const struct in6_addr *addr)
  87 {
  88         return NULL;
  89 }
  90 #endif
  91
  92 static void inet6_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb)
  93 {
  94         struct dst_entry *dst = skb_dst(skb);
  95
  96         if (dst && dst_hold_safe(dst)) {
  97                 const struct rt6_info *rt = (const struct rt6_info *)dst;
  98
  99                 sk->sk_rx_dst = dst;
 100                 inet_sk(sk)->rx_dst_ifindex = skb->skb_iif;
 101                 inet6_sk(sk)->rx_dst_cookie = rt6_get_cookie(rt);
 102         }
 103 }
 104
 105 static __u32 tcp_v6_init_sequence(const struct sk_buff *skb)
 106 {
 107         return secure_tcpv6_sequence_number(ipv6_hdr(skb)->daddr.s6_addr32,
 108                                             ipv6_hdr(skb)->saddr.s6_addr32,
 109                                             tcp_hdr(skb)->dest,
 110                                             tcp_hdr(skb)->source);
 111 }
 112
 113 static int tcp_v6_connect(struct sock *sk, struct sockaddr *uaddr,
 114                           int addr_len)
 115 {
 116         struct sockaddr_in6 *usin = (struct sockaddr_in6 *) uaddr;
 117         struct inet_sock *inet = inet_sk(sk);
 118         struct inet_connection_sock *icsk = inet_csk(sk);
 119         struct ipv6_pinfo *np = inet6_sk(sk);
 120         struct tcp_sock *tp = tcp_sk(sk);
 121         struct in6_addr *saddr = NULL, *final_p, final;
 122         struct ipv6_txoptions *opt;
 123         struct flowi6 fl6;
 124         struct dst_entry *dst;
 125         int addr_type;
 126         int err;
 127
 128         if (addr_len < SIN6_LEN_RFC2133)
 129                 return -EINVAL;
 130
 131         if (usin->sin6_family != AF_INET6)
 132                 return -EAFNOSUPPORT;
 133
 134         memset(&fl6, 0, sizeof(fl6));
 135
 136         if (np->sndflow) {
 137                 fl6.flowlabel = usin->sin6_flowinfo&IPV6_FLOWINFO_MASK;
 138                 IP6_ECN_flow_init(fl6.flowlabel);
 139                 if (fl6.flowlabel&IPV6_FLOWLABEL_MASK) {
 140                         struct ip6_flowlabel *flowlabel;
 141                         flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
 142                         if (!flowlabel)
 143                                 return -EINVAL;
 144                         fl6_sock_release(flowlabel);
 145                 }
 146         }
 147
 148         /*
 149          *      connect() to INADDR_ANY means loopback (BSD'ism).
 150          */
 151
 152         if (ipv6_addr_any(&usin->sin6_addr))
 153                 usin->sin6_addr.s6_addr[15] = 0x1;
 154
 155         addr_type = ipv6_addr_type(&usin->sin6_addr);
 156
 157         if (addr_type & IPV6_ADDR_MULTICAST)
 158                 return -ENETUNREACH;
 159
 160         if (addr_type&IPV6_ADDR_LINKLOCAL) {
 161                 if (addr_len >= sizeof(struct sockaddr_in6) &&
 162                     usin->sin6_scope_id) {
 163                         /* If interface is set while binding, indices
 164                          * must coincide.
 165                          */
 166                         if (sk->sk_bound_dev_if &&
 167                             sk->sk_bound_dev_if != usin->sin6_scope_id)
 168                                 return -EINVAL;
 169
 170                         sk->sk_bound_dev_if = usin->sin6_scope_id;
 171                 }
 172
 173                 /* Connect to link-local address requires an interface */
 174                 if (!sk->sk_bound_dev_if)
 175                         return -EINVAL;
 176         }
 177
 178         if (tp->rx_opt.ts_recent_stamp &&
 179             !ipv6_addr_equal(&sk->sk_v6_daddr, &usin->sin6_addr)) {
 180                 tp->rx_opt.ts_recent = 0;
 181                 tp->rx_opt.ts_recent_stamp = 0;
 182                 tp->write_seq = 0;
 183         }
 184
 185         sk->sk_v6_daddr = usin->sin6_addr;
 186         np->flow_label = fl6.flowlabel;
 187
 188         /*
 189          *      TCP over IPv4
 190          */
 191
 192         if (addr_type == IPV6_ADDR_MAPPED) {
 193                 u32 exthdrlen = icsk->icsk_ext_hdr_len;
 194                 struct sockaddr_in sin;
 195
 196                 SOCK_DEBUG(sk, "connect: ipv4 mapped\n");
 197
 198                 if (__ipv6_only_sock(sk))
 199                         return -ENETUNREACH;
 200
 201                 sin.sin_family = AF_INET;
 202                 sin.sin_port = usin->sin6_port;
 203                 sin.sin_addr.s_addr = usin->sin6_addr.s6_addr32[3];
 204
 205                 icsk->icsk_af_ops = &ipv6_mapped;
 206                 sk->sk_backlog_rcv = tcp_v4_do_rcv;
 207 #ifdef CONFIG_TCP_MD5SIG
 208                 tp->af_specific = &tcp_sock_ipv6_mapped_specific;
 209 #endif
 210
 211                 err = tcp_v4_connect(sk, (struct sockaddr *)&sin, sizeof(sin));
 212
 213                 if (err) {
 214                         icsk->icsk_ext_hdr_len = exthdrlen;
 215                         icsk->icsk_af_ops = &ipv6_specific;
 216                         sk->sk_backlog_rcv = tcp_v6_do_rcv;
 217 #ifdef CONFIG_TCP_MD5SIG
 218                         tp->af_specific = &tcp_sock_ipv6_specific;
 219 #endif
 220                         goto failure;
 221                 }
 222                 np->saddr = sk->sk_v6_rcv_saddr;
 223
 224                 return err;
 225         }
 226
 227         if (!ipv6_addr_any(&sk->sk_v6_rcv_saddr))
 228                 saddr = &sk->sk_v6_rcv_saddr;
 229
 230         fl6.flowi6_proto = IPPROTO_TCP;
 231         fl6.daddr = sk->sk_v6_daddr;
 232         fl6.saddr = saddr ? *saddr : np->saddr;
 233         fl6.flowi6_oif = sk->sk_bound_dev_if;
 234         fl6.flowi6_mark = sk->sk_mark;
 235         fl6.fl6_dport = usin->sin6_port;
 236         fl6.fl6_sport = inet->inet_sport;
 237
 238         opt = rcu_dereference_protected(np->opt, sock_owned_by_user(sk));
 239         final_p = fl6_update_dst(&fl6, opt, &final);
 240
 241         security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));
 242
 243         dst = ip6_dst_lookup_flow(sk, &fl6, final_p);
 244         if (IS_ERR(dst)) {
 245                 err = PTR_ERR(dst);
 246                 goto failure;
 247         }
 248
 249         if (!saddr) {
 250                 saddr = &fl6.saddr;
 251                 sk->sk_v6_rcv_saddr = *saddr;
 252         }
 253
 254         /* set the source address */
 255         np->saddr = *saddr;
 256         inet->inet_rcv_saddr = LOOPBACK4_IPV6;
 257
 258         sk->sk_gso_type = SKB_GSO_TCPV6;
 259         ip6_dst_store(sk, dst, NULL, NULL);
 260
 261         if (tcp_death_row.sysctl_tw_recycle &&
 262             !tp->rx_opt.ts_recent_stamp &&
 263             ipv6_addr_equal(&fl6.daddr, &sk->sk_v6_daddr))
 264                 tcp_fetch_timewait_stamp(sk, dst);
 265
 266         icsk->icsk_ext_hdr_len = 0;
 267         if (opt)
 268                 icsk->icsk_ext_hdr_len = opt->opt_flen +
 269                                          opt->opt_nflen;
 270
 271         tp->rx_opt.mss_clamp = IPV6_MIN_MTU - sizeof(struct tcphdr) - sizeof(struct ipv6hdr);
 272
 273         inet->inet_dport = usin->sin6_port;
 274
 275         tcp_set_state(sk, TCP_SYN_SENT);
 276         err = inet6_hash_connect(&tcp_death_row, sk);
 277         if (err)
 278                 goto late_failure;
 279
 280         sk_set_txhash(sk);
 281
 282         if (!tp->write_seq && likely(!tp->repair))
 283                 tp->write_seq = secure_tcpv6_sequence_number(np->saddr.s6_addr32,
 284                                                              sk->sk_v6_daddr.s6_addr32,
 285                                                              inet->inet_sport,
 286                                                              inet->inet_dport);
 287
 288         err = tcp_connect(sk);
 289         if (err)
 290                 goto late_failure;
 291
 292         return 0;
 293
 294 late_failure:
 295         tcp_set_state(sk, TCP_CLOSE);
 296         __sk_dst_reset(sk);
 297 failure:
 298         inet->inet_dport = 0;
 299         sk->sk_route_caps = 0;
 300         return err;
 301 }
 302
 303 static void tcp_v6_mtu_reduced(struct sock *sk)
 304 {
 305         struct dst_entry *dst;
 306
 307         if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE))
 308                 return;
 309
 310         dst = inet6_csk_update_pmtu(sk, tcp_sk(sk)->mtu_info);
 311         if (!dst)
 312                 return;
 313
 314         if (inet_csk(sk)->icsk_pmtu_cookie > dst_mtu(dst)) {
 315                 tcp_sync_mss(sk, dst_mtu(dst));
 316                 tcp_simple_retransmit(sk);
 317         }
 318 }
 319
 320 static void tcp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 321                 u8 type, u8 code, int offset, __be32 info)
 322 {
 323         const struct ipv6hdr *hdr = (const struct ipv6hdr *)skb->data;
 324         const struct tcphdr *th = (struct tcphdr *)(skb->data+offset);
 325         struct net *net = dev_net(skb->dev);
 326         struct request_sock *fastopen;
 327         struct ipv6_pinfo *np;
 328         struct tcp_sock *tp;
 329         __u32 seq, snd_una;
 330         struct sock *sk;
 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         if (sk->sk_state == TCP_NEW_SYN_RECV)
 350                 return tcp_req_err(sk, seq);
 351
 352         bh_lock_sock(sk);
 353         if (sock_owned_by_user(sk) && type != ICMPV6_PKT_TOOBIG)
 354                 NET_INC_STATS_BH(net, LINUX_MIB_LOCKDROPPEDICMPS);
 355
 356         if (sk->sk_state == TCP_CLOSE)
 357                 goto out;
 358
 359         if (ipv6_hdr(skb)->hop_limit < inet6_sk(sk)->min_hopcount) {
 360                 NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP);
 361                 goto out;
 362         }
 363
 364         tp = tcp_sk(sk);
 365         /* XXX (TFO) - tp->snd_una should be ISN (tcp_create_openreq_child() */
 366         fastopen = tp->fastopen_rsk;
 367         snd_una = fastopen ? tcp_rsk(fastopen)->snt_isn : tp->snd_una;
 368         if (sk->sk_state != TCP_LISTEN &&
 369             !between(seq, snd_una, tp->snd_nxt)) {
 370                 NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
 371                 goto out;
 372         }
 373
 374         np = inet6_sk(sk);
 375
 376         if (type == NDISC_REDIRECT) {
 377                 struct dst_entry *dst = __sk_dst_check(sk, np->dst_cookie);
 378
 379                 if (dst)
 380                         dst->ops->redirect(dst, sk, skb);
 381                 goto out;
 382         }
 383
 384         if (type == ICMPV6_PKT_TOOBIG) {
 385                 /* We are not interested in TCP_LISTEN and open_requests
 386                  * (SYN-ACKs send out by Linux are always <576bytes so
 387                  * they should go through unfragmented).
 388                  */
 389                 if (sk->sk_state == TCP_LISTEN)
 390                         goto out;
 391
 392                 if (!ip6_sk_accept_pmtu(sk))
 393                         goto out;
 394
 395                 tp->mtu_info = ntohl(info);
 396                 if (!sock_owned_by_user(sk))
 397                         tcp_v6_mtu_reduced(sk);
 398                 else if (!test_and_set_bit(TCP_MTU_REDUCED_DEFERRED,
 399                                            &tp->tsq_flags))
 400                         sock_hold(sk);
 401                 goto out;
 402         }
 403
 404         icmpv6_err_convert(type, code, &err);
 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         return crypto_hash_update(&hp->md5_desc, &sg, sizeof(*bp));
 545 }
 546
 547 static int tcp_v6_md5_hash_hdr(char *md5_hash, struct tcp_md5sig_key *key,
 548                                const struct in6_addr *daddr, struct in6_addr *saddr,
 549                                const struct tcphdr *th)
 550 {
 551         struct tcp_md5sig_pool *hp;
 552         struct hash_desc *desc;
 553
 554         hp = tcp_get_md5sig_pool();
 555         if (!hp)
 556                 goto clear_hash_noput;
 557         desc = &hp->md5_desc;
 558
 559         if (crypto_hash_init(desc))
 560                 goto clear_hash;
 561         if (tcp_v6_md5_hash_pseudoheader(hp, daddr, saddr, th->doff << 2))
 562                 goto clear_hash;
 563         if (tcp_md5_hash_header(hp, th))
 564                 goto clear_hash;
 565         if (tcp_md5_hash_key(hp, key))
 566                 goto clear_hash;
 567         if (crypto_hash_final(desc, md5_hash))
 568                 goto clear_hash;
 569
 570         tcp_put_md5sig_pool();
 571         return 0;
 572
 573 clear_hash:
 574         tcp_put_md5sig_pool();
 575 clear_hash_noput:
 576         memset(md5_hash, 0, 16);
 577         return 1;
 578 }
 579
 580 static int tcp_v6_md5_hash_skb(char *md5_hash,
 581                                const struct tcp_md5sig_key *key,
 582                                const struct sock *sk,
 583                                const struct sk_buff *skb)
 584 {
 585         const struct in6_addr *saddr, *daddr;
 586         struct tcp_md5sig_pool *hp;
 587         struct hash_desc *desc;
 588         const struct tcphdr *th = tcp_hdr(skb);
 589
 590         if (sk) { /* valid for establish/request sockets */
 591                 saddr = &sk->sk_v6_rcv_saddr;
 592                 daddr = &sk->sk_v6_daddr;
 593         } else {
 594                 const struct ipv6hdr *ip6h = ipv6_hdr(skb);
 595                 saddr = &ip6h->saddr;
 596                 daddr = &ip6h->daddr;
 597         }
 598
 599         hp = tcp_get_md5sig_pool();
 600         if (!hp)
 601                 goto clear_hash_noput;
 602         desc = &hp->md5_desc;
 603
 604         if (crypto_hash_init(desc))
 605                 goto clear_hash;
 606
 607         if (tcp_v6_md5_hash_pseudoheader(hp, daddr, saddr, skb->len))
 608                 goto clear_hash;
 609         if (tcp_md5_hash_header(hp, th))
 610                 goto clear_hash;
 611         if (tcp_md5_hash_skb_data(hp, skb, th->doff << 2))
 612                 goto clear_hash;
 613         if (tcp_md5_hash_key(hp, key))
 614                 goto clear_hash;
 615         if (crypto_hash_final(desc, md5_hash))
 616                 goto clear_hash;
 617
 618         tcp_put_md5sig_pool();
 619         return 0;
 620
 621 clear_hash:
 622         tcp_put_md5sig_pool();
 623 clear_hash_noput:
 624         memset(md5_hash, 0, 16);
 625         return 1;
 626 }
 627
 628 #endif
 629
 630 static bool tcp_v6_inbound_md5_hash(const struct sock *sk,
 631                                     const struct sk_buff *skb)
 632 {
 633 #ifdef CONFIG_TCP_MD5SIG
 634         const __u8 *hash_location = NULL;
 635         struct tcp_md5sig_key *hash_expected;
 636         const struct ipv6hdr *ip6h = ipv6_hdr(skb);
 637         const struct tcphdr *th = tcp_hdr(skb);
 638         int genhash;
 639         u8 newhash[16];
 640
 641         hash_expected = tcp_v6_md5_do_lookup(sk, &ip6h->saddr);
 642         hash_location = tcp_parse_md5sig_option(th);
 643
 644         /* We've parsed the options - do we have a hash? */
 645         if (!hash_expected && !hash_location)
 646                 return false;
 647
 648         if (hash_expected && !hash_location) {
 649                 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5NOTFOUND);
 650                 return true;
 651         }
 652
 653         if (!hash_expected && hash_location) {
 654                 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5UNEXPECTED);
 655                 return true;
 656         }
 657
 658         /* check the signature */
 659         genhash = tcp_v6_md5_hash_skb(newhash,
 660                                       hash_expected,
 661                                       NULL, skb);
 662
 663         if (genhash || memcmp(hash_location, newhash, 16) != 0) {
 664                 net_info_ratelimited("MD5 Hash %s for [%pI6c]:%u->[%pI6c]:%u\n",
 665                                      genhash ? "failed" : "mismatch",
 666                                      &ip6h->saddr, ntohs(th->source),
 667                                      &ip6h->daddr, ntohs(th->dest));
 668                 return true;
 669         }
 670 #endif
 671         return false;
 672 }
 673
 674 static void tcp_v6_init_req(struct request_sock *req,
 675                             const struct sock *sk_listener,
 676                             struct sk_buff *skb)
 677 {
 678         struct inet_request_sock *ireq = inet_rsk(req);
 679         const struct ipv6_pinfo *np = inet6_sk(sk_listener);
 680
 681         ireq->ir_v6_rmt_addr = ipv6_hdr(skb)->saddr;
 682         ireq->ir_v6_loc_addr = ipv6_hdr(skb)->daddr;
 683
 684         /* So that link locals have meaning */
 685         if (!sk_listener->sk_bound_dev_if &&
 686             ipv6_addr_type(&ireq->ir_v6_rmt_addr) & IPV6_ADDR_LINKLOCAL)
 687                 ireq->ir_iif = tcp_v6_iif(skb);
 688
 689         if (!TCP_SKB_CB(skb)->tcp_tw_isn &&
 690             (ipv6_opt_accepted(sk_listener, skb, &TCP_SKB_CB(skb)->header.h6) ||
 691              np->rxopt.bits.rxinfo ||
 692              np->rxopt.bits.rxoinfo || np->rxopt.bits.rxhlim ||
 693              np->rxopt.bits.rxohlim || np->repflow)) {
 694                 atomic_inc(&skb->users);
 695                 ireq->pktopts = skb;
 696         }
 697 }
 698
 699 static struct dst_entry *tcp_v6_route_req(const struct sock *sk,
 700                                           struct flowi *fl,
 701                                           const struct request_sock *req,
 702                                           bool *strict)
 703 {
 704         if (strict)
 705                 *strict = true;
 706         return inet6_csk_route_req(sk, &fl->u.ip6, req, IPPROTO_TCP);
 707 }
 708
 709 struct request_sock_ops tcp6_request_sock_ops __read_mostly = {
 710         .family         =       AF_INET6,
 711         .obj_size       =       sizeof(struct tcp6_request_sock),
 712         .rtx_syn_ack    =       tcp_rtx_synack,
 713         .send_ack       =       tcp_v6_reqsk_send_ack,
 714         .destructor     =       tcp_v6_reqsk_destructor,
 715         .send_reset     =       tcp_v6_send_reset,
 716         .syn_ack_timeout =      tcp_syn_ack_timeout,
 717 };
 718
 719 static const struct tcp_request_sock_ops tcp_request_sock_ipv6_ops = {
 720         .mss_clamp      =       IPV6_MIN_MTU - sizeof(struct tcphdr) -
 721                                 sizeof(struct ipv6hdr),
 722 #ifdef CONFIG_TCP_MD5SIG
 723         .req_md5_lookup =       tcp_v6_md5_lookup,
 724         .calc_md5_hash  =       tcp_v6_md5_hash_skb,
 725 #endif
 726         .init_req       =       tcp_v6_init_req,
 727 #ifdef CONFIG_SYN_COOKIES
 728         .cookie_init_seq =      cookie_v6_init_sequence,
 729 #endif
 730         .route_req      =       tcp_v6_route_req,
 731         .init_seq       =       tcp_v6_init_sequence,
 732         .send_synack    =       tcp_v6_send_synack,
 733 };
 734
 735 static void tcp_v6_send_response(const struct sock *sk, struct sk_buff *skb, u32 seq,
 736                                  u32 ack, u32 win, u32 tsval, u32 tsecr,
 737                                  int oif, struct tcp_md5sig_key *key, int rst,
 738                                  u8 tclass, u32 label)
 739 {
 740         const struct tcphdr *th = tcp_hdr(skb);
 741         struct tcphdr *t1;
 742         struct sk_buff *buff;
 743         struct flowi6 fl6;
 744         struct net *net = sk ? sock_net(sk) : dev_net(skb_dst(skb)->dev);
 745         struct sock *ctl_sk = net->ipv6.tcp_sk;
 746         unsigned int tot_len = sizeof(struct tcphdr);
 747         struct dst_entry *dst;
 748         __be32 *topt;
 749
 750         if (tsecr)
 751                 tot_len += TCPOLEN_TSTAMP_ALIGNED;
 752 #ifdef CONFIG_TCP_MD5SIG
 753         if (key)
 754                 tot_len += TCPOLEN_MD5SIG_ALIGNED;
 755 #endif
 756
 757         buff = alloc_skb(MAX_HEADER + sizeof(struct ipv6hdr) + tot_len,
 758                          GFP_ATOMIC);
 759         if (!buff)
 760                 return;
 761
 762         skb_reserve(buff, MAX_HEADER + sizeof(struct ipv6hdr) + tot_len);
 763
 764         t1 = (struct tcphdr *) skb_push(buff, tot_len);
 765         skb_reset_transport_header(buff);
 766
 767         /* Swap the send and the receive. */
 768         memset(t1, 0, sizeof(*t1));
 769         t1->dest = th->source;
 770         t1->source = th->dest;
 771         t1->doff = tot_len / 4;
 772         t1->seq = htonl(seq);
 773         t1->ack_seq = htonl(ack);
 774         t1->ack = !rst || !th->ack;
 775         t1->rst = rst;
 776         t1->window = htons(win);
 777
 778         topt = (__be32 *)(t1 + 1);
 779
 780         if (tsecr) {
 781                 *topt++ = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
 782                                 (TCPOPT_TIMESTAMP << 8) | TCPOLEN_TIMESTAMP);
 783                 *topt++ = htonl(tsval);
 784                 *topt++ = htonl(tsecr);
 785         }
 786
 787 #ifdef CONFIG_TCP_MD5SIG
 788         if (key) {
 789                 *topt++ = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
 790                                 (TCPOPT_MD5SIG << 8) | TCPOLEN_MD5SIG);
 791                 tcp_v6_md5_hash_hdr((__u8 *)topt, key,
 792                                     &ipv6_hdr(skb)->saddr,
 793                                     &ipv6_hdr(skb)->daddr, t1);
 794         }
 795 #endif
 796
 797         memset(&fl6, 0, sizeof(fl6));
 798         fl6.daddr = ipv6_hdr(skb)->saddr;
 799         fl6.saddr = ipv6_hdr(skb)->daddr;
 800         fl6.flowlabel = label;
 801
 802         buff->ip_summed = CHECKSUM_PARTIAL;
 803         buff->csum = 0;
 804
 805         __tcp_v6_send_check(buff, &fl6.saddr, &fl6.daddr);
 806
 807         fl6.flowi6_proto = IPPROTO_TCP;
 808         if (rt6_need_strict(&fl6.daddr) && !oif)
 809                 fl6.flowi6_oif = tcp_v6_iif(skb);
 810         else
 811                 fl6.flowi6_oif = oif;
 812         fl6.flowi6_mark = IP6_REPLY_MARK(net, skb->mark);
 813         fl6.fl6_dport = t1->dest;
 814         fl6.fl6_sport = t1->source;
 815         security_skb_classify_flow(skb, flowi6_to_flowi(&fl6));
 816
 817         /* Pass a socket to ip6_dst_lookup either it is for RST
 818          * Underlying function will use this to retrieve the network
 819          * namespace
 820          */
 821         dst = ip6_dst_lookup_flow(ctl_sk, &fl6, NULL);
 822         if (!IS_ERR(dst)) {
 823                 skb_dst_set(buff, dst);
 824                 ip6_xmit(ctl_sk, buff, &fl6, NULL, tclass);
 825                 TCP_INC_STATS_BH(net, TCP_MIB_OUTSEGS);
 826                 if (rst)
 827                         TCP_INC_STATS_BH(net, TCP_MIB_OUTRSTS);
 828                 return;
 829         }
 830
 831         kfree_skb(buff);
 832 }
 833
 834 static void tcp_v6_send_reset(const struct sock *sk, struct sk_buff *skb)
 835 {
 836         const struct tcphdr *th = tcp_hdr(skb);
 837         u32 seq = 0, ack_seq = 0;
 838         struct tcp_md5sig_key *key = NULL;
 839 #ifdef CONFIG_TCP_MD5SIG
 840         const __u8 *hash_location = NULL;
 841         struct ipv6hdr *ipv6h = ipv6_hdr(skb);
 842         unsigned char newhash[16];
 843         int genhash;
 844         struct sock *sk1 = NULL;
 845 #endif
 846         int oif;
 847
 848         if (th->rst)
 849                 return;
 850
 851         /* If sk not NULL, it means we did a successful lookup and incoming
 852          * route had to be correct. prequeue might have dropped our dst.
 853          */
 854         if (!sk && !ipv6_unicast_destination(skb))
 855                 return;
 856
 857 #ifdef CONFIG_TCP_MD5SIG
 858         hash_location = tcp_parse_md5sig_option(th);
 859         if (!sk && hash_location) {
 860                 /*
 861                  * active side is lost. Try to find listening socket through
 862                  * source port, and then find md5 key through listening socket.
 863                  * we are not loose security here:
 864                  * Incoming packet is checked with md5 hash with finding key,
 865                  * no RST generated if md5 hash doesn't match.
 866                  */
 867                 sk1 = inet6_lookup_listener(dev_net(skb_dst(skb)->dev),
 868                                            &tcp_hashinfo, &ipv6h->saddr,
 869                                            th->source, &ipv6h->daddr,
 870                                            ntohs(th->source), tcp_v6_iif(skb));
 871                 if (!sk1)
 872                         return;
 873
 874                 rcu_read_lock();
 875                 key = tcp_v6_md5_do_lookup(sk1, &ipv6h->saddr);
 876                 if (!key)
 877                         goto release_sk1;
 878
 879                 genhash = tcp_v6_md5_hash_skb(newhash, key, NULL, skb);
 880                 if (genhash || memcmp(hash_location, newhash, 16) != 0)
 881                         goto release_sk1;
 882         } else {
 883                 key = sk ? tcp_v6_md5_do_lookup(sk, &ipv6h->saddr) : NULL;
 884         }
 885 #endif
 886
 887         if (th->ack)
 888                 seq = ntohl(th->ack_seq);
 889         else
 890                 ack_seq = ntohl(th->seq) + th->syn + th->fin + skb->len -
 891                           (th->doff << 2);
 892
 893         oif = sk ? sk->sk_bound_dev_if : 0;
 894         tcp_v6_send_response(sk, skb, seq, ack_seq, 0, 0, 0, oif, key, 1, 0, 0);
 895
 896 #ifdef CONFIG_TCP_MD5SIG
 897 release_sk1:
 898         if (sk1) {
 899                 rcu_read_unlock();
 900                 sock_put(sk1);
 901         }
 902 #endif
 903 }
 904
 905 static void tcp_v6_send_ack(const struct sock *sk, struct sk_buff *skb, u32 seq,
 906                             u32 ack, u32 win, u32 tsval, u32 tsecr, int oif,
 907                             struct tcp_md5sig_key *key, u8 tclass,
 908                             u32 label)
 909 {
 910         tcp_v6_send_response(sk, skb, seq, ack, win, tsval, tsecr, oif, key, 0,
 911                              tclass, label);
 912 }
 913
 914 static void tcp_v6_timewait_ack(struct sock *sk, struct sk_buff *skb)
 915 {
 916         struct inet_timewait_sock *tw = inet_twsk(sk);
 917         struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
 918
 919         tcp_v6_send_ack(sk, skb, tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
 920                         tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
 921                         tcp_time_stamp + tcptw->tw_ts_offset,
 922                         tcptw->tw_ts_recent, tw->tw_bound_dev_if, tcp_twsk_md5_key(tcptw),
 923                         tw->tw_tclass, cpu_to_be32(tw->tw_flowlabel));
 924
 925         inet_twsk_put(tw);
 926 }
 927
 928 static void tcp_v6_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb,
 929                                   struct request_sock *req)
 930 {
 931         /* sk->sk_state == TCP_LISTEN -> for regular TCP_SYN_RECV
 932          * sk->sk_state == TCP_SYN_RECV -> for Fast Open.
 933          */
 934         tcp_v6_send_ack(sk, skb, (sk->sk_state == TCP_LISTEN) ?
 935                         tcp_rsk(req)->snt_isn + 1 : tcp_sk(sk)->snd_nxt,
 936                         tcp_rsk(req)->rcv_nxt, req->rsk_rcv_wnd,
 937                         tcp_time_stamp, req->ts_recent, sk->sk_bound_dev_if,
 938                         tcp_v6_md5_do_lookup(sk, &ipv6_hdr(skb)->daddr),
 939                         0, 0);
 940 }
 941
 942
 943 static struct sock *tcp_v6_cookie_check(struct sock *sk, struct sk_buff *skb)
 944 {
 945 #ifdef CONFIG_SYN_COOKIES
 946         const struct tcphdr *th = tcp_hdr(skb);
 947
 948         if (!th->syn)
 949                 sk = cookie_v6_check(sk, skb);
 950 #endif
 951         return sk;
 952 }
 953
 954 static int tcp_v6_conn_request(struct sock *sk, struct sk_buff *skb)
 955 {
 956         if (skb->protocol == htons(ETH_P_IP))
 957                 return tcp_v4_conn_request(sk, skb);
 958
 959         if (!ipv6_unicast_destination(skb))
 960                 goto drop;
 961
 962         return tcp_conn_request(&tcp6_request_sock_ops,
 963                                 &tcp_request_sock_ipv6_ops, sk, skb);
 964
 965 drop:
 966         NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
 967         return 0; /* don't send reset */
 968 }
 969
 970 static struct sock *tcp_v6_syn_recv_sock(const struct sock *sk, struct sk_buff *skb,
 971                                          struct request_sock *req,
 972                                          struct dst_entry *dst,
 973                                          struct request_sock *req_unhash,
 974                                          bool *own_req)
 975 {
 976         struct inet_request_sock *ireq;
 977         struct ipv6_pinfo *newnp;
 978         const struct ipv6_pinfo *np = inet6_sk(sk);
 979         struct ipv6_txoptions *opt;
 980         struct tcp6_sock *newtcp6sk;
 981         struct inet_sock *newinet;
 982         struct tcp_sock *newtp;
 983         struct sock *newsk;
 984 #ifdef CONFIG_TCP_MD5SIG
 985         struct tcp_md5sig_key *key;
 986 #endif
 987         struct flowi6 fl6;
 988
 989         if (skb->protocol == htons(ETH_P_IP)) {
 990                 /*
 991                  *      v6 mapped
 992                  */
 993
 994                 newsk = tcp_v4_syn_recv_sock(sk, skb, req, dst,
 995                                              req_unhash, own_req);
 996
 997                 if (!newsk)
 998                         return NULL;
 999
1000                 newtcp6sk = (struct tcp6_sock *)newsk;
1001                 inet_sk(newsk)->pinet6 = &newtcp6sk->inet6;
1002
1003                 newinet = inet_sk(newsk);
1004                 newnp = inet6_sk(newsk);
1005                 newtp = tcp_sk(newsk);
1006
1007                 memcpy(newnp, np, sizeof(struct ipv6_pinfo));
1008
1009                 newnp->saddr = newsk->sk_v6_rcv_saddr;
1010
1011                 inet_csk(newsk)->icsk_af_ops = &ipv6_mapped;
1012                 newsk->sk_backlog_rcv = tcp_v4_do_rcv;
1013 #ifdef CONFIG_TCP_MD5SIG
1014                 newtp->af_specific = &tcp_sock_ipv6_mapped_specific;
1015 #endif
1016
1017                 newnp->ipv6_ac_list = NULL;
1018                 newnp->ipv6_fl_list = NULL;
1019                 newnp->pktoptions  = NULL;
1020                 newnp->opt         = NULL;
1021                 newnp->mcast_oif   = tcp_v6_iif(skb);
1022                 newnp->mcast_hops  = ipv6_hdr(skb)->hop_limit;
1023                 newnp->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(skb));
1024                 if (np->repflow)
1025                         newnp->flow_label = ip6_flowlabel(ipv6_hdr(skb));
1026
1027                 /*
1028                  * No need to charge this sock to the relevant IPv6 refcnt debug socks count
1029                  * here, tcp_create_openreq_child now does this for us, see the comment in
1030                  * that function for the gory details. -acme
1031                  */
1032
1033                 /* It is tricky place. Until this moment IPv4 tcp
1034                    worked with IPv6 icsk.icsk_af_ops.
1035                    Sync it now.
1036                  */
1037                 tcp_sync_mss(newsk, inet_csk(newsk)->icsk_pmtu_cookie);
1038
1039                 return newsk;
1040         }
1041
1042         ireq = inet_rsk(req);
1043
1044         if (sk_acceptq_is_full(sk))
1045                 goto out_overflow;
1046
1047         if (!dst) {
1048                 dst = inet6_csk_route_req(sk, &fl6, req, IPPROTO_TCP);
1049                 if (!dst)
1050                         goto out;
1051         }
1052
1053         newsk = tcp_create_openreq_child(sk, req, skb);
1054         if (!newsk)
1055                 goto out_nonewsk;
1056
1057         /*
1058          * No need to charge this sock to the relevant IPv6 refcnt debug socks
1059          * count here, tcp_create_openreq_child now does this for us, see the
1060          * comment in that function for the gory details. -acme
1061          */
1062
1063         newsk->sk_gso_type = SKB_GSO_TCPV6;
1064         ip6_dst_store(newsk, dst, NULL, NULL);
1065         inet6_sk_rx_dst_set(newsk, skb);
1066
1067         newtcp6sk = (struct tcp6_sock *)newsk;
1068         inet_sk(newsk)->pinet6 = &newtcp6sk->inet6;
1069
1070         newtp = tcp_sk(newsk);
1071         newinet = inet_sk(newsk);
1072         newnp = inet6_sk(newsk);
1073
1074         memcpy(newnp, np, sizeof(struct ipv6_pinfo));
1075
1076         newsk->sk_v6_daddr = ireq->ir_v6_rmt_addr;
1077         newnp->saddr = ireq->ir_v6_loc_addr;
1078         newsk->sk_v6_rcv_saddr = ireq->ir_v6_loc_addr;
1079         newsk->sk_bound_dev_if = ireq->ir_iif;
1080
1081         /* Now IPv6 options...
1082
1083            First: no IPv4 options.
1084          */
1085         newinet->inet_opt = NULL;
1086         newnp->ipv6_ac_list = NULL;
1087         newnp->ipv6_fl_list = NULL;
1088
1089         /* Clone RX bits */
1090         newnp->rxopt.all = np->rxopt.all;
1091
1092         newnp->pktoptions = NULL;
1093         newnp->opt        = NULL;
1094         newnp->mcast_oif  = tcp_v6_iif(skb);
1095         newnp->mcast_hops = ipv6_hdr(skb)->hop_limit;
1096         newnp->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(skb));
1097         if (np->repflow)
1098                 newnp->flow_label = ip6_flowlabel(ipv6_hdr(skb));
1099
1100         /* Clone native IPv6 options from listening socket (if any)
1101
1102            Yes, keeping reference count would be much more clever,
1103            but we make one more one thing there: reattach optmem
1104            to newsk.
1105          */
1106         opt = rcu_dereference(np->opt);
1107         if (opt) {
1108                 opt = ipv6_dup_options(newsk, opt);
1109                 RCU_INIT_POINTER(newnp->opt, opt);
1110         }
1111         inet_csk(newsk)->icsk_ext_hdr_len = 0;
1112         if (opt)
1113                 inet_csk(newsk)->icsk_ext_hdr_len = opt->opt_nflen +
1114                                                     opt->opt_flen;
1115
1116         tcp_ca_openreq_child(newsk, dst);
1117
1118         tcp_sync_mss(newsk, dst_mtu(dst));
1119         newtp->advmss = dst_metric_advmss(dst);
1120         if (tcp_sk(sk)->rx_opt.user_mss &&
1121             tcp_sk(sk)->rx_opt.user_mss < newtp->advmss)
1122                 newtp->advmss = tcp_sk(sk)->rx_opt.user_mss;
1123
1124         tcp_initialize_rcv_mss(newsk);
1125
1126         newinet->inet_daddr = newinet->inet_saddr = LOOPBACK4_IPV6;
1127         newinet->inet_rcv_saddr = LOOPBACK4_IPV6;
1128
1129 #ifdef CONFIG_TCP_MD5SIG
1130         /* Copy over the MD5 key from the original socket */
1131         key = tcp_v6_md5_do_lookup(sk, &newsk->sk_v6_daddr);
1132         if (key) {
1133                 /* We're using one, so create a matching key
1134                  * on the newsk structure. If we fail to get
1135                  * memory, then we end up not copying the key
1136                  * across. Shucks.
1137                  */
1138                 tcp_md5_do_add(newsk, (union tcp_md5_addr *)&newsk->sk_v6_daddr,
1139                                AF_INET6, key->key, key->keylen,
1140                                sk_gfp_atomic(sk, GFP_ATOMIC));
1141         }
1142 #endif
1143
1144         if (__inet_inherit_port(sk, newsk) < 0) {
1145                 inet_csk_prepare_forced_close(newsk);
1146                 tcp_done(newsk);
1147                 goto out;
1148         }
1149         *own_req = inet_ehash_nolisten(newsk, req_to_sk(req_unhash));
1150         if (*own_req) {
1151                 tcp_move_syn(newtp, req);
1152
1153                 /* Clone pktoptions received with SYN, if we own the req */
1154                 if (ireq->pktopts) {
1155                         newnp->pktoptions = skb_clone(ireq->pktopts,
1156                                                       sk_gfp_atomic(sk, GFP_ATOMIC));
1157                         consume_skb(ireq->pktopts);
1158                         ireq->pktopts = NULL;
1159                         if (newnp->pktoptions)
1160                                 skb_set_owner_r(newnp->pktoptions, newsk);
1161                 }
1162         }
1163
1164         return newsk;
1165
1166 out_overflow:
1167         NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
1168 out_nonewsk:
1169         dst_release(dst);
1170 out:
1171         NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
1172         return NULL;
1173 }
1174
1175 /* The socket must have it's spinlock held when we get
1176  * here, unless it is a TCP_LISTEN socket.
1177  *
1178  * We have a potential double-lock case here, so even when
1179  * doing backlog processing we use the BH locking scheme.
1180  * This is because we cannot sleep with the original spinlock
1181  * held.
1182  */
1183 static int tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb)
1184 {
1185         struct ipv6_pinfo *np = inet6_sk(sk);
1186         struct tcp_sock *tp;
1187         struct sk_buff *opt_skb = NULL;
1188
1189         /* Imagine: socket is IPv6. IPv4 packet arrives,
1190            goes to IPv4 receive handler and backlogged.
1191            From backlog it always goes here. Kerboom...
1192            Fortunately, tcp_rcv_established and rcv_established
1193            handle them correctly, but it is not case with
1194            tcp_v6_hnd_req and tcp_v6_send_reset().   --ANK
1195          */
1196
1197         if (skb->protocol == htons(ETH_P_IP))
1198                 return tcp_v4_do_rcv(sk, skb);
1199
1200         if (sk_filter(sk, skb))
1201                 goto discard;
1202
1203         /*
1204          *      socket locking is here for SMP purposes as backlog rcv
1205          *      is currently called with bh processing disabled.
1206          */
1207
1208         /* Do Stevens' IPV6_PKTOPTIONS.
1209
1210            Yes, guys, it is the only place in our code, where we
1211            may make it not affecting IPv4.
1212            The rest of code is protocol independent,
1213            and I do not like idea to uglify IPv4.
1214
1215            Actually, all the idea behind IPV6_PKTOPTIONS
1216            looks not very well thought. For now we latch
1217            options, received in the last packet, enqueued
1218            by tcp. Feel free to propose better solution.
1219                                                --ANK (980728)
1220          */
1221         if (np->rxopt.all)
1222                 opt_skb = skb_clone(skb, sk_gfp_atomic(sk, GFP_ATOMIC));
1223
1224         if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
1225                 struct dst_entry *dst = sk->sk_rx_dst;
1226
1227                 sock_rps_save_rxhash(sk, skb);
1228                 sk_mark_napi_id(sk, skb);
1229                 if (dst) {
1230                         if (inet_sk(sk)->rx_dst_ifindex != skb->skb_iif ||
1231                             dst->ops->check(dst, np->rx_dst_cookie) == NULL) {
1232                                 dst_release(dst);
1233                                 sk->sk_rx_dst = NULL;
1234                         }
1235                 }
1236
1237                 tcp_rcv_established(sk, skb, tcp_hdr(skb), skb->len);
1238                 if (opt_skb)
1239                         goto ipv6_pktoptions;
1240                 return 0;
1241         }
1242
1243         if (tcp_checksum_complete(skb))
1244                 goto csum_err;
1245
1246         if (sk->sk_state == TCP_LISTEN) {
1247                 struct sock *nsk = tcp_v6_cookie_check(sk, skb);
1248
1249                 if (!nsk)
1250                         goto discard;
1251
1252                 if (nsk != sk) {
1253                         sock_rps_save_rxhash(nsk, skb);
1254                         sk_mark_napi_id(nsk, skb);
1255                         if (tcp_child_process(sk, nsk, skb))
1256                                 goto reset;
1257                         if (opt_skb)
1258                                 __kfree_skb(opt_skb);
1259                         return 0;
1260                 }
1261         } else
1262                 sock_rps_save_rxhash(sk, skb);
1263
1264         if (tcp_rcv_state_process(sk, skb))
1265                 goto reset;
1266         if (opt_skb)
1267                 goto ipv6_pktoptions;
1268         return 0;
1269
1270 reset:
1271         tcp_v6_send_reset(sk, skb);
1272 discard:
1273         if (opt_skb)
1274                 __kfree_skb(opt_skb);
1275         kfree_skb(skb);
1276         return 0;
1277 csum_err:
1278         TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_CSUMERRORS);
1279         TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_INERRS);
1280         goto discard;
1281
1282
1283 ipv6_pktoptions:
1284         /* Do you ask, what is it?
1285
1286            1. skb was enqueued by tcp.
1287            2. skb is added to tail of read queue, rather than out of order.
1288            3. socket is not in passive state.
1289            4. Finally, it really contains options, which user wants to receive.
1290          */
1291         tp = tcp_sk(sk);
1292         if (TCP_SKB_CB(opt_skb)->end_seq == tp->rcv_nxt &&
1293             !((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN))) {
1294                 if (np->rxopt.bits.rxinfo || np->rxopt.bits.rxoinfo)
1295                         np->mcast_oif = tcp_v6_iif(opt_skb);
1296                 if (np->rxopt.bits.rxhlim || np->rxopt.bits.rxohlim)
1297                         np->mcast_hops = ipv6_hdr(opt_skb)->hop_limit;
1298                 if (np->rxopt.bits.rxflow || np->rxopt.bits.rxtclass)
1299                         np->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(opt_skb));
1300                 if (np->repflow)
1301                         np->flow_label = ip6_flowlabel(ipv6_hdr(opt_skb));
1302                 if (ipv6_opt_accepted(sk, opt_skb, &TCP_SKB_CB(opt_skb)->header.h6)) {
1303                         skb_set_owner_r(opt_skb, sk);
1304                         opt_skb = xchg(&np->pktoptions, opt_skb);
1305                 } else {
1306                         __kfree_skb(opt_skb);
1307                         opt_skb = xchg(&np->pktoptions, NULL);
1308                 }
1309         }
1310
1311         kfree_skb(opt_skb);
1312         return 0;
1313 }
1314
1315 static void tcp_v6_fill_cb(struct sk_buff *skb, const struct ipv6hdr *hdr,
1316                            const struct tcphdr *th)
1317 {
1318         /* This is tricky: we move IP6CB at its correct location into
1319          * TCP_SKB_CB(). It must be done after xfrm6_policy_check(), because
1320          * _decode_session6() uses IP6CB().
1321          * barrier() makes sure compiler won't play aliasing games.
1322          */
1323         memmove(&TCP_SKB_CB(skb)->header.h6, IP6CB(skb),
1324                 sizeof(struct inet6_skb_parm));
1325         barrier();
1326
1327         TCP_SKB_CB(skb)->seq = ntohl(th->seq);
1328         TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
1329                                     skb->len - th->doff*4);
1330         TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
1331         TCP_SKB_CB(skb)->tcp_flags = tcp_flag_byte(th);
1332         TCP_SKB_CB(skb)->tcp_tw_isn = 0;
1333         TCP_SKB_CB(skb)->ip_dsfield = ipv6_get_dsfield(hdr);
1334         TCP_SKB_CB(skb)->sacked = 0;
1335 }
1336
1337 static void tcp_v6_restore_cb(struct sk_buff *skb)
1338 {
1339         /* We need to move header back to the beginning if xfrm6_policy_check()
1340          * and tcp_v6_fill_cb() are going to be called again.
1341          */
1342         memmove(IP6CB(skb), &TCP_SKB_CB(skb)->header.h6,
1343                 sizeof(struct inet6_skb_parm));
1344 }
1345
1346 static int tcp_v6_rcv(struct sk_buff *skb)
1347 {
1348         const struct tcphdr *th;
1349         const struct ipv6hdr *hdr;
1350         struct sock *sk;
1351         int ret;
1352         struct net *net = dev_net(skb->dev);
1353
1354         if (skb->pkt_type != PACKET_HOST)
1355                 goto discard_it;
1356
1357         /*
1358          *      Count it even if it's bad.
1359          */
1360         TCP_INC_STATS_BH(net, TCP_MIB_INSEGS);
1361
1362         if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
1363                 goto discard_it;
1364
1365         th = tcp_hdr(skb);
1366
1367         if (th->doff < sizeof(struct tcphdr)/4)
1368                 goto bad_packet;
1369         if (!pskb_may_pull(skb, th->doff*4))
1370                 goto discard_it;
1371
1372         if (skb_checksum_init(skb, IPPROTO_TCP, ip6_compute_pseudo))
1373                 goto csum_error;
1374
1375         th = tcp_hdr(skb);
1376         hdr = ipv6_hdr(skb);
1377
1378 lookup:
1379         sk = __inet6_lookup_skb(&tcp_hashinfo, skb, th->source, th->dest,
1380                                 inet6_iif(skb));
1381         if (!sk)
1382                 goto no_tcp_socket;
1383
1384 process:
1385         if (sk->sk_state == TCP_TIME_WAIT)
1386                 goto do_time_wait;
1387
1388         if (sk->sk_state == TCP_NEW_SYN_RECV) {
1389                 struct request_sock *req = inet_reqsk(sk);
1390                 struct sock *nsk = NULL;
1391
1392                 sk = req->rsk_listener;
1393                 tcp_v6_fill_cb(skb, hdr, th);
1394                 if (tcp_v6_inbound_md5_hash(sk, skb)) {
1395                         reqsk_put(req);
1396                         goto discard_it;
1397                 }
1398                 if (likely(sk->sk_state == TCP_LISTEN)) {
1399                         nsk = tcp_check_req(sk, skb, req, false);
1400                 } else {
1401                         inet_csk_reqsk_queue_drop_and_put(sk, req);
1402                         goto lookup;
1403                 }
1404                 if (!nsk) {
1405                         reqsk_put(req);
1406                         goto discard_it;
1407                 }
1408                 if (nsk == sk) {
1409                         sock_hold(sk);
1410                         reqsk_put(req);
1411                         tcp_v6_restore_cb(skb);
1412                 } else if (tcp_child_process(sk, nsk, skb)) {
1413                         tcp_v6_send_reset(nsk, skb);
1414                         goto discard_it;
1415                 } else {
1416                         return 0;
1417                 }
1418         }
1419         if (hdr->hop_limit < inet6_sk(sk)->min_hopcount) {
1420                 NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP);
1421                 goto discard_and_relse;
1422         }
1423
1424         if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb))
1425                 goto discard_and_relse;
1426
1427         tcp_v6_fill_cb(skb, hdr, th);
1428
1429         if (tcp_v6_inbound_md5_hash(sk, skb))
1430                 goto discard_and_relse;
1431
1432         if (sk_filter(sk, skb))
1433                 goto discard_and_relse;
1434
1435         skb->dev = NULL;
1436
1437         if (sk->sk_state == TCP_LISTEN) {
1438                 ret = tcp_v6_do_rcv(sk, skb);
1439                 goto put_and_return;
1440         }
1441
1442         sk_incoming_cpu_update(sk);
1443
1444         bh_lock_sock_nested(sk);
1445         tcp_sk(sk)->segs_in += max_t(u16, 1, skb_shinfo(skb)->gso_segs);
1446         ret = 0;
1447         if (!sock_owned_by_user(sk)) {
1448                 if (!tcp_prequeue(sk, skb))
1449                         ret = tcp_v6_do_rcv(sk, skb);
1450         } else if (unlikely(sk_add_backlog(sk, skb,
1451                                            sk->sk_rcvbuf + sk->sk_sndbuf))) {
1452                 bh_unlock_sock(sk);
1453                 NET_INC_STATS_BH(net, LINUX_MIB_TCPBACKLOGDROP);
1454                 goto discard_and_relse;
1455         }
1456         bh_unlock_sock(sk);
1457
1458 put_and_return:
1459         sock_put(sk);
1460         return ret ? -1 : 0;
1461
1462 no_tcp_socket:
1463         if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb))
1464                 goto discard_it;
1465
1466         tcp_v6_fill_cb(skb, hdr, th);
1467
1468         if (tcp_checksum_complete(skb)) {
1469 csum_error:
1470                 TCP_INC_STATS_BH(net, TCP_MIB_CSUMERRORS);
1471 bad_packet:
1472                 TCP_INC_STATS_BH(net, TCP_MIB_INERRS);
1473         } else {
1474                 tcp_v6_send_reset(NULL, skb);
1475         }
1476
1477 discard_it:
1478         kfree_skb(skb);
1479         return 0;
1480
1481 discard_and_relse:
1482         sock_put(sk);
1483         goto discard_it;
1484
1485 do_time_wait:
1486         if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
1487                 inet_twsk_put(inet_twsk(sk));
1488                 goto discard_it;
1489         }
1490
1491         tcp_v6_fill_cb(skb, hdr, th);
1492
1493         if (tcp_checksum_complete(skb)) {
1494                 inet_twsk_put(inet_twsk(sk));
1495                 goto csum_error;
1496         }
1497
1498         switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) {
1499         case TCP_TW_SYN:
1500         {
1501                 struct sock *sk2;
1502
1503                 sk2 = inet6_lookup_listener(dev_net(skb->dev), &tcp_hashinfo,
1504                                             &ipv6_hdr(skb)->saddr, th->source,
1505                                             &ipv6_hdr(skb)->daddr,
1506                                             ntohs(th->dest), tcp_v6_iif(skb));
1507                 if (sk2) {
1508                         struct inet_timewait_sock *tw = inet_twsk(sk);
1509                         inet_twsk_deschedule_put(tw);
1510                         sk = sk2;
1511                         tcp_v6_restore_cb(skb);
1512                         goto process;
1513                 }
1514                 /* Fall through to ACK */
1515         }
1516         case TCP_TW_ACK:
1517                 tcp_v6_timewait_ack(sk, skb);
1518                 break;
1519         case TCP_TW_RST:
1520                 tcp_v6_restore_cb(skb);
1521                 goto no_tcp_socket;
1522         case TCP_TW_SUCCESS:
1523                 ;
1524         }
1525         goto discard_it;
1526 }
1527
1528 static void tcp_v6_early_demux(struct sk_buff *skb)
1529 {
1530         const struct ipv6hdr *hdr;
1531         const struct tcphdr *th;
1532         struct sock *sk;
1533
1534         if (skb->pkt_type != PACKET_HOST)
1535                 return;
1536
1537         if (!pskb_may_pull(skb, skb_transport_offset(skb) + sizeof(struct tcphdr)))
1538                 return;
1539
1540         hdr = ipv6_hdr(skb);
1541         th = tcp_hdr(skb);
1542
1543         if (th->doff < sizeof(struct tcphdr) / 4)
1544                 return;
1545
1546         /* Note : We use inet6_iif() here, not tcp_v6_iif() */
1547         sk = __inet6_lookup_established(dev_net(skb->dev), &tcp_hashinfo,
1548                                         &hdr->saddr, th->source,
1549                                         &hdr->daddr, ntohs(th->dest),
1550                                         inet6_iif(skb));
1551         if (sk) {
1552                 skb->sk = sk;
1553                 skb->destructor = sock_edemux;
1554                 if (sk_fullsock(sk)) {
1555                         struct dst_entry *dst = READ_ONCE(sk->sk_rx_dst);
1556
1557                         if (dst)
1558                                 dst = dst_check(dst, inet6_sk(sk)->rx_dst_cookie);
1559                         if (dst &&
1560                             inet_sk(sk)->rx_dst_ifindex == skb->skb_iif)
1561                                 skb_dst_set_noref(skb, dst);
1562                 }
1563         }
1564 }
1565
1566 static struct timewait_sock_ops tcp6_timewait_sock_ops = {
1567         .twsk_obj_size  = sizeof(struct tcp6_timewait_sock),
1568         .twsk_unique    = tcp_twsk_unique,
1569         .twsk_destructor = tcp_twsk_destructor,
1570 };
1571
1572 static const struct inet_connection_sock_af_ops ipv6_specific = {
1573         .queue_xmit        = inet6_csk_xmit,
1574         .send_check        = tcp_v6_send_check,
1575         .rebuild_header    = inet6_sk_rebuild_header,
1576         .sk_rx_dst_set     = inet6_sk_rx_dst_set,
1577         .conn_request      = tcp_v6_conn_request,
1578         .syn_recv_sock     = tcp_v6_syn_recv_sock,
1579         .net_header_len    = sizeof(struct ipv6hdr),
1580         .net_frag_header_len = sizeof(struct frag_hdr),
1581         .setsockopt        = ipv6_setsockopt,
1582         .getsockopt        = ipv6_getsockopt,
1583         .addr2sockaddr     = inet6_csk_addr2sockaddr,
1584         .sockaddr_len      = sizeof(struct sockaddr_in6),
1585         .bind_conflict     = inet6_csk_bind_conflict,
1586 #ifdef CONFIG_COMPAT
1587         .compat_setsockopt = compat_ipv6_setsockopt,
1588         .compat_getsockopt = compat_ipv6_getsockopt,
1589 #endif
1590         .mtu_reduced       = tcp_v6_mtu_reduced,
1591 };
1592
1593 #ifdef CONFIG_TCP_MD5SIG
1594 static const struct tcp_sock_af_ops tcp_sock_ipv6_specific = {
1595         .md5_lookup     =       tcp_v6_md5_lookup,
1596         .calc_md5_hash  =       tcp_v6_md5_hash_skb,
1597         .md5_parse      =       tcp_v6_parse_md5_keys,
1598 };
1599 #endif
1600
1601 /*
1602  *      TCP over IPv4 via INET6 API
1603  */
1604 static const struct inet_connection_sock_af_ops ipv6_mapped = {
1605         .queue_xmit        = ip_queue_xmit,
1606         .send_check        = tcp_v4_send_check,
1607         .rebuild_header    = inet_sk_rebuild_header,
1608         .sk_rx_dst_set     = inet_sk_rx_dst_set,
1609         .conn_request      = tcp_v6_conn_request,
1610         .syn_recv_sock     = tcp_v6_syn_recv_sock,
1611         .net_header_len    = sizeof(struct iphdr),
1612         .setsockopt        = ipv6_setsockopt,
1613         .getsockopt        = ipv6_getsockopt,
1614         .addr2sockaddr     = inet6_csk_addr2sockaddr,
1615         .sockaddr_len      = sizeof(struct sockaddr_in6),
1616         .bind_conflict     = inet6_csk_bind_conflict,
1617 #ifdef CONFIG_COMPAT
1618         .compat_setsockopt = compat_ipv6_setsockopt,
1619         .compat_getsockopt = compat_ipv6_getsockopt,
1620 #endif
1621         .mtu_reduced       = tcp_v4_mtu_reduced,
1622 };
1623
1624 #ifdef CONFIG_TCP_MD5SIG
1625 static const struct tcp_sock_af_ops tcp_sock_ipv6_mapped_specific = {
1626         .md5_lookup     =       tcp_v4_md5_lookup,
1627         .calc_md5_hash  =       tcp_v4_md5_hash_skb,
1628         .md5_parse      =       tcp_v6_parse_md5_keys,
1629 };
1630 #endif
1631
1632 /* NOTE: A lot of things set to zero explicitly by call to
1633  *       sk_alloc() so need not be done here.
1634  */
1635 static int tcp_v6_init_sock(struct sock *sk)
1636 {
1637         struct inet_connection_sock *icsk = inet_csk(sk);
1638
1639         tcp_init_sock(sk);
1640
1641         icsk->icsk_af_ops = &ipv6_specific;
1642
1643 #ifdef CONFIG_TCP_MD5SIG
1644         tcp_sk(sk)->af_specific = &tcp_sock_ipv6_specific;
1645 #endif
1646
1647         return 0;
1648 }
1649
1650 static void tcp_v6_destroy_sock(struct sock *sk)
1651 {
1652         tcp_v4_destroy_sock(sk);
1653         inet6_destroy_sock(sk);
1654 }
1655
1656 #ifdef CONFIG_PROC_FS
1657 /* Proc filesystem TCPv6 sock list dumping. */
1658 static void get_openreq6(struct seq_file *seq,
1659                          const struct request_sock *req, int i)
1660 {
1661         long ttd = req->rsk_timer.expires - jiffies;
1662         const struct in6_addr *src = &inet_rsk(req)->ir_v6_loc_addr;
1663         const struct in6_addr *dest = &inet_rsk(req)->ir_v6_rmt_addr;
1664
1665         if (ttd < 0)
1666                 ttd = 0;
1667
1668         seq_printf(seq,
1669                    "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
1670                    "%02X %08X:%08X %02X:%08lX %08X %5u %8d %d %d %pK\n",
1671                    i,
1672                    src->s6_addr32[0], src->s6_addr32[1],
1673                    src->s6_addr32[2], src->s6_addr32[3],
1674                    inet_rsk(req)->ir_num,
1675                    dest->s6_addr32[0], dest->s6_addr32[1],
1676                    dest->s6_addr32[2], dest->s6_addr32[3],
1677                    ntohs(inet_rsk(req)->ir_rmt_port),
1678                    TCP_SYN_RECV,
1679                    0, 0, /* could print option size, but that is af dependent. */
1680                    1,   /* timers active (only the expire timer) */
1681                    jiffies_to_clock_t(ttd),
1682                    req->num_timeout,
1683                    from_kuid_munged(seq_user_ns(seq),
1684                                     sock_i_uid(req->rsk_listener)),
1685                    0,  /* non standard timer */
1686                    0, /* open_requests have no inode */
1687                    0, req);
1688 }
1689
1690 static void get_tcp6_sock(struct seq_file *seq, struct sock *sp, int i)
1691 {
1692         const struct in6_addr *dest, *src;
1693         __u16 destp, srcp;
1694         int timer_active;
1695         unsigned long timer_expires;
1696         const struct inet_sock *inet = inet_sk(sp);
1697         const struct tcp_sock *tp = tcp_sk(sp);
1698         const struct inet_connection_sock *icsk = inet_csk(sp);
1699         const struct fastopen_queue *fastopenq = &icsk->icsk_accept_queue.fastopenq;
1700         int rx_queue;
1701         int state;
1702
1703         dest  = &sp->sk_v6_daddr;
1704         src   = &sp->sk_v6_rcv_saddr;
1705         destp = ntohs(inet->inet_dport);
1706         srcp  = ntohs(inet->inet_sport);
1707
1708         if (icsk->icsk_pending == ICSK_TIME_RETRANS) {
1709                 timer_active    = 1;
1710                 timer_expires   = icsk->icsk_timeout;
1711         } else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
1712                 timer_active    = 4;
1713                 timer_expires   = icsk->icsk_timeout;
1714         } else if (timer_pending(&sp->sk_timer)) {
1715                 timer_active    = 2;
1716                 timer_expires   = sp->sk_timer.expires;
1717         } else {
1718                 timer_active    = 0;
1719                 timer_expires = jiffies;
1720         }
1721
1722         state = sk_state_load(sp);
1723         if (state == TCP_LISTEN)
1724                 rx_queue = sp->sk_ack_backlog;
1725         else
1726                 /* Because we don't lock the socket,
1727                  * we might find a transient negative value.
1728                  */
1729                 rx_queue = max_t(int, tp->rcv_nxt - tp->copied_seq, 0);
1730
1731         seq_printf(seq,
1732                    "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
1733                    "%02X %08X:%08X %02X:%08lX %08X %5u %8d %lu %d %pK %lu %lu %u %u %d\n",
1734                    i,
1735                    src->s6_addr32[0], src->s6_addr32[1],
1736                    src->s6_addr32[2], src->s6_addr32[3], srcp,
1737                    dest->s6_addr32[0], dest->s6_addr32[1],
1738                    dest->s6_addr32[2], dest->s6_addr32[3], destp,
1739                    state,
1740                    tp->write_seq - tp->snd_una,
1741                    rx_queue,
1742                    timer_active,
1743                    jiffies_delta_to_clock_t(timer_expires - jiffies),
1744                    icsk->icsk_retransmits,
1745                    from_kuid_munged(seq_user_ns(seq), sock_i_uid(sp)),
1746                    icsk->icsk_probes_out,
1747                    sock_i_ino(sp),
1748                    atomic_read(&sp->sk_refcnt), sp,
1749                    jiffies_to_clock_t(icsk->icsk_rto),
1750                    jiffies_to_clock_t(icsk->icsk_ack.ato),
1751                    (icsk->icsk_ack.quick << 1) | icsk->icsk_ack.pingpong,
1752                    tp->snd_cwnd,
1753                    state == TCP_LISTEN ?
1754                         fastopenq->max_qlen :
1755                         (tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh)
1756                    );
1757 }
1758
1759 static void get_timewait6_sock(struct seq_file *seq,
1760                                struct inet_timewait_sock *tw, int i)
1761 {
1762         long delta = tw->tw_timer.expires - jiffies;
1763         const struct in6_addr *dest, *src;
1764         __u16 destp, srcp;
1765
1766         dest = &tw->tw_v6_daddr;
1767         src  = &tw->tw_v6_rcv_saddr;
1768         destp = ntohs(tw->tw_dport);
1769         srcp  = ntohs(tw->tw_sport);
1770
1771         seq_printf(seq,
1772                    "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
1773                    "%02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK\n",
1774                    i,
1775                    src->s6_addr32[0], src->s6_addr32[1],
1776                    src->s6_addr32[2], src->s6_addr32[3], srcp,
1777                    dest->s6_addr32[0], dest->s6_addr32[1],
1778                    dest->s6_addr32[2], dest->s6_addr32[3], destp,
1779                    tw->tw_substate, 0, 0,
1780                    3, jiffies_delta_to_clock_t(delta), 0, 0, 0, 0,
1781                    atomic_read(&tw->tw_refcnt), tw);
1782 }
1783
1784 static int tcp6_seq_show(struct seq_file *seq, void *v)
1785 {
1786         struct tcp_iter_state *st;
1787         struct sock *sk = v;
1788
1789         if (v == SEQ_START_TOKEN) {
1790                 seq_puts(seq,
1791                          "  sl  "
1792                          "local_address                         "
1793                          "remote_address                        "
1794                          "st tx_queue rx_queue tr tm->when retrnsmt"
1795                          "   uid  timeout inode\n");
1796                 goto out;
1797         }
1798         st = seq->private;
1799
1800         if (sk->sk_state == TCP_TIME_WAIT)
1801                 get_timewait6_sock(seq, v, st->num);
1802         else if (sk->sk_state == TCP_NEW_SYN_RECV)
1803                 get_openreq6(seq, v, st->num);
1804         else
1805                 get_tcp6_sock(seq, v, st->num);
1806 out:
1807         return 0;
1808 }
1809
1810 static const struct file_operations tcp6_afinfo_seq_fops = {
1811         .owner   = THIS_MODULE,
1812         .open    = tcp_seq_open,
1813         .read    = seq_read,
1814         .llseek  = seq_lseek,
1815         .release = seq_release_net
1816 };
1817
1818 static struct tcp_seq_afinfo tcp6_seq_afinfo = {
1819         .name           = "tcp6",
1820         .family         = AF_INET6,
1821         .seq_fops       = &tcp6_afinfo_seq_fops,
1822         .seq_ops        = {
1823                 .show           = tcp6_seq_show,
1824         },
1825 };
1826
1827 int __net_init tcp6_proc_init(struct net *net)
1828 {
1829         return tcp_proc_register(net, &tcp6_seq_afinfo);
1830 }
1831
1832 void tcp6_proc_exit(struct net *net)
1833 {
1834         tcp_proc_unregister(net, &tcp6_seq_afinfo);
1835 }
1836 #endif
1837
1838 static void tcp_v6_clear_sk(struct sock *sk, int size)
1839 {
1840         struct inet_sock *inet = inet_sk(sk);
1841
1842         /* we do not want to clear pinet6 field, because of RCU lookups */
1843         sk_prot_clear_nulls(sk, offsetof(struct inet_sock, pinet6));
1844
1845         size -= offsetof(struct inet_sock, pinet6) + sizeof(inet->pinet6);
1846         memset(&inet->pinet6 + 1, 0, size);
1847 }
1848
1849 struct proto tcpv6_prot = {
1850         .name                   = "TCPv6",
1851         .owner                  = THIS_MODULE,
1852         .close                  = tcp_close,
1853         .connect                = tcp_v6_connect,
1854         .disconnect             = tcp_disconnect,
1855         .accept                 = inet_csk_accept,
1856         .ioctl                  = tcp_ioctl,
1857         .init                   = tcp_v6_init_sock,
1858         .destroy                = tcp_v6_destroy_sock,
1859         .shutdown               = tcp_shutdown,
1860         .setsockopt             = tcp_setsockopt,
1861         .getsockopt             = tcp_getsockopt,
1862         .recvmsg                = tcp_recvmsg,
1863         .sendmsg                = tcp_sendmsg,
1864         .sendpage               = tcp_sendpage,
1865         .backlog_rcv            = tcp_v6_do_rcv,
1866         .release_cb             = tcp_release_cb,
1867         .hash                   = inet_hash,
1868         .unhash                 = inet_unhash,
1869         .get_port               = inet_csk_get_port,
1870         .enter_memory_pressure  = tcp_enter_memory_pressure,
1871         .stream_memory_free     = tcp_stream_memory_free,
1872         .sockets_allocated      = &tcp_sockets_allocated,
1873         .memory_allocated       = &tcp_memory_allocated,
1874         .memory_pressure        = &tcp_memory_pressure,
1875         .orphan_count           = &tcp_orphan_count,
1876         .sysctl_mem             = sysctl_tcp_mem,
1877         .sysctl_wmem            = sysctl_tcp_wmem,
1878         .sysctl_rmem            = sysctl_tcp_rmem,
1879         .max_header             = MAX_TCP_HEADER,
1880         .obj_size               = sizeof(struct tcp6_sock),
1881         .slab_flags             = SLAB_DESTROY_BY_RCU,
1882         .twsk_prot              = &tcp6_timewait_sock_ops,
1883         .rsk_prot               = &tcp6_request_sock_ops,
1884         .h.hashinfo             = &tcp_hashinfo,
1885         .no_autobind            = true,
1886 #ifdef CONFIG_COMPAT
1887         .compat_setsockopt      = compat_tcp_setsockopt,
1888         .compat_getsockopt      = compat_tcp_getsockopt,
1889 #endif
1890 #ifdef CONFIG_MEMCG_KMEM
1891         .proto_cgroup           = tcp_proto_cgroup,
1892 #endif
1893         .clear_sk               = tcp_v6_clear_sk,
1894 };
1895
1896 static const struct inet6_protocol tcpv6_protocol = {
1897         .early_demux    =       tcp_v6_early_demux,
1898         .handler        =       tcp_v6_rcv,
1899         .err_handler    =       tcp_v6_err,
1900         .flags          =       INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
1901 };
1902
1903 static struct inet_protosw tcpv6_protosw = {
1904         .type           =       SOCK_STREAM,
1905         .protocol       =       IPPROTO_TCP,
1906         .prot           =       &tcpv6_prot,
1907         .ops            =       &inet6_stream_ops,
1908         .flags          =       INET_PROTOSW_PERMANENT |
1909                                 INET_PROTOSW_ICSK,
1910 };
1911
1912 static int __net_init tcpv6_net_init(struct net *net)
1913 {
1914         return inet_ctl_sock_create(&net->ipv6.tcp_sk, PF_INET6,
1915                                     SOCK_RAW, IPPROTO_TCP, net);
1916 }
1917
1918 static void __net_exit tcpv6_net_exit(struct net *net)
1919 {
1920         inet_ctl_sock_destroy(net->ipv6.tcp_sk);
1921 }
1922
1923 static void __net_exit tcpv6_net_exit_batch(struct list_head *net_exit_list)
1924 {
1925         inet_twsk_purge(&tcp_hashinfo, &tcp_death_row, AF_INET6);
1926 }
1927
1928 static struct pernet_operations tcpv6_net_ops = {
1929         .init       = tcpv6_net_init,
1930         .exit       = tcpv6_net_exit,
1931         .exit_batch = tcpv6_net_exit_batch,
1932 };
1933
1934 int __init tcpv6_init(void)
1935 {
1936         int ret;
1937
1938         ret = inet6_add_protocol(&tcpv6_protocol, IPPROTO_TCP);
1939         if (ret)
1940                 goto out;
1941
1942         /* register inet6 protocol */
1943         ret = inet6_register_protosw(&tcpv6_protosw);
1944         if (ret)
1945                 goto out_tcpv6_protocol;
1946
1947         ret = register_pernet_subsys(&tcpv6_net_ops);
1948         if (ret)
1949                 goto out_tcpv6_protosw;
1950 out:
1951         return ret;
1952
1953 out_tcpv6_protosw:
1954         inet6_unregister_protosw(&tcpv6_protosw);
1955 out_tcpv6_protocol:
1956         inet6_del_protocol(&tcpv6_protocol, IPPROTO_TCP);
1957         goto out;
1958 }
1959
1960 void tcpv6_exit(void)
1961 {
1962         unregister_pernet_subsys(&tcpv6_net_ops);
1963         inet6_unregister_protosw(&tcpv6_protosw);
1964         inet6_del_protocol(&tcpv6_protocol, IPPROTO_TCP);
1965 }