net/ipv6/tcp_ipv6.c

   1 /*
   2  *      TCP over IPv6
   3  *      Linux INET6 implementation
   4  *
   5  *      Authors:
   6  *      Pedro Roque             <[email protected]>
   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(struct sock *sk, struct sk_buff *skb);
  74 static void     tcp_v6_reqsk_send_ack(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(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) {
  97                 const struct rt6_info *rt = (const struct rt6_info *)dst;
  98
  99                 dst_hold(dst);
 100                 sk->sk_rx_dst = dst;
 101                 inet_sk(sk)->rx_dst_ifindex = skb->skb_iif;
 102                 if (rt->rt6i_node)
 103                         inet6_sk(sk)->rx_dst_cookie = rt->rt6i_node->fn_sernum;
 104         }
 105 }
 106
 107 static __u32 tcp_v6_init_sequence(const struct sk_buff *skb)
 108 {
 109         return secure_tcpv6_sequence_number(ipv6_hdr(skb)->daddr.s6_addr32,
 110                                             ipv6_hdr(skb)->saddr.s6_addr32,
 111                                             tcp_hdr(skb)->dest,
 112                                             tcp_hdr(skb)->source);
 113 }
 114
 115 static int tcp_v6_connect(struct sock *sk, struct sockaddr *uaddr,
 116                           int addr_len)
 117 {
 118         struct sockaddr_in6 *usin = (struct sockaddr_in6 *) uaddr;
 119         struct inet_sock *inet = inet_sk(sk);
 120         struct inet_connection_sock *icsk = inet_csk(sk);
 121         struct ipv6_pinfo *np = inet6_sk(sk);
 122         struct tcp_sock *tp = tcp_sk(sk);
 123         struct in6_addr *saddr = NULL, *final_p, final;
 124         struct rt6_info *rt;
 125         struct flowi6 fl6;
 126         struct dst_entry *dst;
 127         int addr_type;
 128         int err;
 129
 130         if (addr_len < SIN6_LEN_RFC2133)
 131                 return -EINVAL;
 132
 133         if (usin->sin6_family != AF_INET6)
 134                 return -EAFNOSUPPORT;
 135
 136         memset(&fl6, 0, sizeof(fl6));
 137
 138         if (np->sndflow) {
 139                 fl6.flowlabel = usin->sin6_flowinfo&IPV6_FLOWINFO_MASK;
 140                 IP6_ECN_flow_init(fl6.flowlabel);
 141                 if (fl6.flowlabel&IPV6_FLOWLABEL_MASK) {
 142                         struct ip6_flowlabel *flowlabel;
 143                         flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
 144                         if (!flowlabel)
 145                                 return -EINVAL;
 146                         fl6_sock_release(flowlabel);
 147                 }
 148         }
 149
 150         /*
 151          *      connect() to INADDR_ANY means loopback (BSD'ism).
 152          */
 153
 154         if (ipv6_addr_any(&usin->sin6_addr))
 155                 usin->sin6_addr.s6_addr[15] = 0x1;
 156
 157         addr_type = ipv6_addr_type(&usin->sin6_addr);
 158
 159         if (addr_type & IPV6_ADDR_MULTICAST)
 160                 return -ENETUNREACH;
 161
 162         if (addr_type&IPV6_ADDR_LINKLOCAL) {
 163                 if (addr_len >= sizeof(struct sockaddr_in6) &&
 164                     usin->sin6_scope_id) {
 165                         /* If interface is set while binding, indices
 166                          * must coincide.
 167                          */
 168                         if (sk->sk_bound_dev_if &&
 169                             sk->sk_bound_dev_if != usin->sin6_scope_id)
 170                                 return -EINVAL;
 171
 172                         sk->sk_bound_dev_if = usin->sin6_scope_id;
 173                 }
 174
 175                 /* Connect to link-local address requires an interface */
 176                 if (!sk->sk_bound_dev_if)
 177                         return -EINVAL;
 178         }
 179
 180         if (tp->rx_opt.ts_recent_stamp &&
 181             !ipv6_addr_equal(&sk->sk_v6_daddr, &usin->sin6_addr)) {
 182                 tp->rx_opt.ts_recent = 0;
 183                 tp->rx_opt.ts_recent_stamp = 0;
 184                 tp->write_seq = 0;
 185         }
 186
 187         sk->sk_v6_daddr = usin->sin6_addr;
 188         np->flow_label = fl6.flowlabel;
 189
 190         /*
 191          *      TCP over IPv4
 192          */
 193
 194         if (addr_type == IPV6_ADDR_MAPPED) {
 195                 u32 exthdrlen = icsk->icsk_ext_hdr_len;
 196                 struct sockaddr_in sin;
 197
 198                 SOCK_DEBUG(sk, "connect: ipv4 mapped\n");
 199
 200                 if (__ipv6_only_sock(sk))
 201                         return -ENETUNREACH;
 202
 203                 sin.sin_family = AF_INET;
 204                 sin.sin_port = usin->sin6_port;
 205                 sin.sin_addr.s_addr = usin->sin6_addr.s6_addr32[3];
 206
 207                 icsk->icsk_af_ops = &ipv6_mapped;
 208                 sk->sk_backlog_rcv = tcp_v4_do_rcv;
 209 #ifdef CONFIG_TCP_MD5SIG
 210                 tp->af_specific = &tcp_sock_ipv6_mapped_specific;
 211 #endif
 212
 213                 err = tcp_v4_connect(sk, (struct sockaddr *)&sin, sizeof(sin));
 214
 215                 if (err) {
 216                         icsk->icsk_ext_hdr_len = exthdrlen;
 217                         icsk->icsk_af_ops = &ipv6_specific;
 218                         sk->sk_backlog_rcv = tcp_v6_do_rcv;
 219 #ifdef CONFIG_TCP_MD5SIG
 220                         tp->af_specific = &tcp_sock_ipv6_specific;
 221 #endif
 222                         goto failure;
 223                 }
 224                 np->saddr = sk->sk_v6_rcv_saddr;
 225
 226                 return err;
 227         }
 228
 229         if (!ipv6_addr_any(&sk->sk_v6_rcv_saddr))
 230                 saddr = &sk->sk_v6_rcv_saddr;
 231
 232         fl6.flowi6_proto = IPPROTO_TCP;
 233         fl6.daddr = sk->sk_v6_daddr;
 234         fl6.saddr = saddr ? *saddr : np->saddr;
 235         fl6.flowi6_oif = sk->sk_bound_dev_if;
 236         fl6.flowi6_mark = sk->sk_mark;
 237         fl6.fl6_dport = usin->sin6_port;
 238         fl6.fl6_sport = inet->inet_sport;
 239
 240         final_p = fl6_update_dst(&fl6, np->opt, &final);
 241
 242         security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));
 243
 244         dst = ip6_dst_lookup_flow(sk, &fl6, final_p);
 245         if (IS_ERR(dst)) {
 246                 err = PTR_ERR(dst);
 247                 goto failure;
 248         }
 249
 250         if (!saddr) {
 251                 saddr = &fl6.saddr;
 252                 sk->sk_v6_rcv_saddr = *saddr;
 253         }
 254
 255         /* set the source address */
 256         np->saddr = *saddr;
 257         inet->inet_rcv_saddr = LOOPBACK4_IPV6;
 258
 259         sk->sk_gso_type = SKB_GSO_TCPV6;
 260         __ip6_dst_store(sk, dst, NULL, NULL);
 261
 262         rt = (struct rt6_info *) dst;
 263         if (tcp_death_row.sysctl_tw_recycle &&
 264             !tp->rx_opt.ts_recent_stamp &&
 265             ipv6_addr_equal(&rt->rt6i_dst.addr, &sk->sk_v6_daddr))
 266                 tcp_fetch_timewait_stamp(sk, dst);
 267
 268         icsk->icsk_ext_hdr_len = 0;
 269         if (np->opt)
 270                 icsk->icsk_ext_hdr_len = (np->opt->opt_flen +
 271                                           np->opt->opt_nflen);
 272
 273         tp->rx_opt.mss_clamp = IPV6_MIN_MTU - sizeof(struct tcphdr) - sizeof(struct ipv6hdr);
 274
 275         inet->inet_dport = usin->sin6_port;
 276
 277         tcp_set_state(sk, TCP_SYN_SENT);
 278         err = inet6_hash_connect(&tcp_death_row, sk);
 279         if (err)
 280                 goto late_failure;
 281
 282         ip6_set_txhash(sk);
 283
 284         if (!tp->write_seq && likely(!tp->repair))
 285                 tp->write_seq = secure_tcpv6_sequence_number(np->saddr.s6_addr32,
 286                                                              sk->sk_v6_daddr.s6_addr32,
 287                                                              inet->inet_sport,
 288                                                              inet->inet_dport);
 289
 290         err = tcp_connect(sk);
 291         if (err)
 292                 goto late_failure;
 293
 294         return 0;
 295
 296 late_failure:
 297         tcp_set_state(sk, TCP_CLOSE);
 298         __sk_dst_reset(sk);
 299 failure:
 300         inet->inet_dport = 0;
 301         sk->sk_route_caps = 0;
 302         return err;
 303 }
 304
 305 static void tcp_v6_mtu_reduced(struct sock *sk)
 306 {
 307         struct dst_entry *dst;
 308
 309         if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE))
 310                 return;
 311
 312         dst = inet6_csk_update_pmtu(sk, tcp_sk(sk)->mtu_info);
 313         if (!dst)
 314                 return;
 315
 316         if (inet_csk(sk)->icsk_pmtu_cookie > dst_mtu(dst)) {
 317                 tcp_sync_mss(sk, dst_mtu(dst));
 318                 tcp_simple_retransmit(sk);
 319         }
 320 }
 321
 322 static void tcp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 323                 u8 type, u8 code, int offset, __be32 info)
 324 {
 325         const struct ipv6hdr *hdr = (const struct ipv6hdr *)skb->data;
 326         const struct tcphdr *th = (struct tcphdr *)(skb->data+offset);
 327         struct net *net = dev_net(skb->dev);
 328         struct request_sock *fastopen;
 329         struct ipv6_pinfo *np;
 330         struct tcp_sock *tp;
 331         __u32 seq, snd_una;
 332         struct sock *sk;
 333         int err;
 334
 335         sk = __inet6_lookup_established(net, &tcp_hashinfo,
 336                                         &hdr->daddr, th->dest,
 337                                         &hdr->saddr, ntohs(th->source),
 338                                         skb->dev->ifindex);
 339
 340         if (!sk) {
 341                 ICMP6_INC_STATS_BH(net, __in6_dev_get(skb->dev),
 342                                    ICMP6_MIB_INERRORS);
 343                 return;
 344         }
 345
 346         if (sk->sk_state == TCP_TIME_WAIT) {
 347                 inet_twsk_put(inet_twsk(sk));
 348                 return;
 349         }
 350         seq = ntohl(th->seq);
 351         if (sk->sk_state == TCP_NEW_SYN_RECV)
 352                 return tcp_req_err(sk, seq);
 353
 354         bh_lock_sock(sk);
 355         if (sock_owned_by_user(sk) && type != ICMPV6_PKT_TOOBIG)
 356                 NET_INC_STATS_BH(net, LINUX_MIB_LOCKDROPPEDICMPS);
 357
 358         if (sk->sk_state == TCP_CLOSE)
 359                 goto out;
 360
 361         if (ipv6_hdr(skb)->hop_limit < inet6_sk(sk)->min_hopcount) {
 362                 NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP);
 363                 goto out;
 364         }
 365
 366         tp = tcp_sk(sk);
 367         /* XXX (TFO) - tp->snd_una should be ISN (tcp_create_openreq_child() */
 368         fastopen = tp->fastopen_rsk;
 369         snd_una = fastopen ? tcp_rsk(fastopen)->snt_isn : tp->snd_una;
 370         if (sk->sk_state != TCP_LISTEN &&
 371             !between(seq, snd_una, tp->snd_nxt)) {
 372                 NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
 373                 goto out;
 374         }
 375
 376         np = inet6_sk(sk);
 377
 378         if (type == NDISC_REDIRECT) {
 379                 struct dst_entry *dst = __sk_dst_check(sk, np->dst_cookie);
 380
 381                 if (dst)
 382                         dst->ops->redirect(dst, sk, skb);
 383                 goto out;
 384         }
 385
 386         if (type == ICMPV6_PKT_TOOBIG) {
 387                 /* We are not interested in TCP_LISTEN and open_requests
 388                  * (SYN-ACKs send out by Linux are always <576bytes so
 389                  * they should go through unfragmented).
 390                  */
 391                 if (sk->sk_state == TCP_LISTEN)
 392                         goto out;
 393
 394                 if (!ip6_sk_accept_pmtu(sk))
 395                         goto out;
 396
 397                 tp->mtu_info = ntohl(info);
 398                 if (!sock_owned_by_user(sk))
 399                         tcp_v6_mtu_reduced(sk);
 400                 else if (!test_and_set_bit(TCP_MTU_REDUCED_DEFERRED,
 401                                            &tp->tsq_flags))
 402                         sock_hold(sk);
 403                 goto out;
 404         }
 405
 406         icmpv6_err_convert(type, code, &err);
 407
 408         /* Might be for an request_sock */
 409         switch (sk->sk_state) {
 410         case TCP_SYN_SENT:
 411         case TCP_SYN_RECV:
 412                 /* Only in fast or simultaneous open. If a fast open socket is
 413                  * is already accepted it is treated as a connected one below.
 414                  */
 415                 if (fastopen && !fastopen->sk)
 416                         break;
 417
 418                 if (!sock_owned_by_user(sk)) {
 419                         sk->sk_err = err;
 420                         sk->sk_error_report(sk);                /* Wake people up to see the error (see connect in sock.c) */
 421
 422                         tcp_done(sk);
 423                 } else
 424                         sk->sk_err_soft = err;
 425                 goto out;
 426         }
 427
 428         if (!sock_owned_by_user(sk) && np->recverr) {
 429                 sk->sk_err = err;
 430                 sk->sk_error_report(sk);
 431         } else
 432                 sk->sk_err_soft = err;
 433
 434 out:
 435         bh_unlock_sock(sk);
 436         sock_put(sk);
 437 }
 438
 439
 440 static int tcp_v6_send_synack(struct sock *sk, struct dst_entry *dst,
 441                               struct flowi *fl,
 442                               struct request_sock *req,
 443                               u16 queue_mapping,
 444                               struct tcp_fastopen_cookie *foc)
 445 {
 446         struct inet_request_sock *ireq = inet_rsk(req);
 447         struct ipv6_pinfo *np = inet6_sk(sk);
 448         struct flowi6 *fl6 = &fl->u.ip6;
 449         struct sk_buff *skb;
 450         int err = -ENOMEM;
 451
 452         /* First, grab a route. */
 453         if (!dst && (dst = inet6_csk_route_req(sk, fl6, req)) == NULL)
 454                 goto done;
 455
 456         skb = tcp_make_synack(sk, dst, req, foc);
 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                 skb_set_queue_mapping(skb, queue_mapping);
 467                 err = ip6_xmit(sk, skb, fl6, np->opt, np->tclass);
 468                 err = net_xmit_eval(err);
 469         }
 470
 471 done:
 472         return err;
 473 }
 474
 475
 476 static void tcp_v6_reqsk_destructor(struct request_sock *req)
 477 {
 478         kfree_skb(inet_rsk(req)->pktopts);
 479 }
 480
 481 #ifdef CONFIG_TCP_MD5SIG
 482 static struct tcp_md5sig_key *tcp_v6_md5_do_lookup(struct sock *sk,
 483                                                    const struct in6_addr *addr)
 484 {
 485         return tcp_md5_do_lookup(sk, (union tcp_md5_addr *)addr, AF_INET6);
 486 }
 487
 488 static struct tcp_md5sig_key *tcp_v6_md5_lookup(struct sock *sk,
 489                                                 const struct sock *addr_sk)
 490 {
 491         return tcp_v6_md5_do_lookup(sk, &addr_sk->sk_v6_daddr);
 492 }
 493
 494 static int tcp_v6_parse_md5_keys(struct sock *sk, char __user *optval,
 495                                  int optlen)
 496 {
 497         struct tcp_md5sig cmd;
 498         struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)&cmd.tcpm_addr;
 499
 500         if (optlen < sizeof(cmd))
 501                 return -EINVAL;
 502
 503         if (copy_from_user(&cmd, optval, sizeof(cmd)))
 504                 return -EFAULT;
 505
 506         if (sin6->sin6_family != AF_INET6)
 507                 return -EINVAL;
 508
 509         if (!cmd.tcpm_keylen) {
 510                 if (ipv6_addr_v4mapped(&sin6->sin6_addr))
 511                         return tcp_md5_do_del(sk, (union tcp_md5_addr *)&sin6->sin6_addr.s6_addr32[3],
 512                                               AF_INET);
 513                 return tcp_md5_do_del(sk, (union tcp_md5_addr *)&sin6->sin6_addr,
 514                                       AF_INET6);
 515         }
 516
 517         if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN)
 518                 return -EINVAL;
 519
 520         if (ipv6_addr_v4mapped(&sin6->sin6_addr))
 521                 return tcp_md5_do_add(sk, (union tcp_md5_addr *)&sin6->sin6_addr.s6_addr32[3],
 522                                       AF_INET, cmd.tcpm_key, cmd.tcpm_keylen, GFP_KERNEL);
 523
 524         return tcp_md5_do_add(sk, (union tcp_md5_addr *)&sin6->sin6_addr,
 525                               AF_INET6, cmd.tcpm_key, cmd.tcpm_keylen, GFP_KERNEL);
 526 }
 527
 528 static int tcp_v6_md5_hash_pseudoheader(struct tcp_md5sig_pool *hp,
 529                                         const struct in6_addr *daddr,
 530                                         const struct in6_addr *saddr, int nbytes)
 531 {
 532         struct tcp6_pseudohdr *bp;
 533         struct scatterlist sg;
 534
 535         bp = &hp->md5_blk.ip6;
 536         /* 1. TCP pseudo-header (RFC2460) */
 537         bp->saddr = *saddr;
 538         bp->daddr = *daddr;
 539         bp->protocol = cpu_to_be32(IPPROTO_TCP);
 540         bp->len = cpu_to_be32(nbytes);
 541
 542         sg_init_one(&sg, bp, sizeof(*bp));
 543         return crypto_hash_update(&hp->md5_desc, &sg, sizeof(*bp));
 544 }
 545
 546 static int tcp_v6_md5_hash_hdr(char *md5_hash, struct tcp_md5sig_key *key,
 547                                const struct in6_addr *daddr, struct in6_addr *saddr,
 548                                const struct tcphdr *th)
 549 {
 550         struct tcp_md5sig_pool *hp;
 551         struct hash_desc *desc;
 552
 553         hp = tcp_get_md5sig_pool();
 554         if (!hp)
 555                 goto clear_hash_noput;
 556         desc = &hp->md5_desc;
 557
 558         if (crypto_hash_init(desc))
 559                 goto clear_hash;
 560         if (tcp_v6_md5_hash_pseudoheader(hp, daddr, saddr, th->doff << 2))
 561                 goto clear_hash;
 562         if (tcp_md5_hash_header(hp, th))
 563                 goto clear_hash;
 564         if (tcp_md5_hash_key(hp, key))
 565                 goto clear_hash;
 566         if (crypto_hash_final(desc, md5_hash))
 567                 goto clear_hash;
 568
 569         tcp_put_md5sig_pool();
 570         return 0;
 571
 572 clear_hash:
 573         tcp_put_md5sig_pool();
 574 clear_hash_noput:
 575         memset(md5_hash, 0, 16);
 576         return 1;
 577 }
 578
 579 static int tcp_v6_md5_hash_skb(char *md5_hash,
 580                                const struct tcp_md5sig_key *key,
 581                                const struct sock *sk,
 582                                const struct sk_buff *skb)
 583 {
 584         const struct in6_addr *saddr, *daddr;
 585         struct tcp_md5sig_pool *hp;
 586         struct hash_desc *desc;
 587         const struct tcphdr *th = tcp_hdr(skb);
 588
 589         if (sk) { /* valid for establish/request sockets */
 590                 saddr = &sk->sk_v6_rcv_saddr;
 591                 daddr = &sk->sk_v6_daddr;
 592         } else {
 593                 const struct ipv6hdr *ip6h = ipv6_hdr(skb);
 594                 saddr = &ip6h->saddr;
 595                 daddr = &ip6h->daddr;
 596         }
 597
 598         hp = tcp_get_md5sig_pool();
 599         if (!hp)
 600                 goto clear_hash_noput;
 601         desc = &hp->md5_desc;
 602
 603         if (crypto_hash_init(desc))
 604                 goto clear_hash;
 605
 606         if (tcp_v6_md5_hash_pseudoheader(hp, daddr, saddr, skb->len))
 607                 goto clear_hash;
 608         if (tcp_md5_hash_header(hp, th))
 609                 goto clear_hash;
 610         if (tcp_md5_hash_skb_data(hp, skb, th->doff << 2))
 611                 goto clear_hash;
 612         if (tcp_md5_hash_key(hp, key))
 613                 goto clear_hash;
 614         if (crypto_hash_final(desc, md5_hash))
 615                 goto clear_hash;
 616
 617         tcp_put_md5sig_pool();
 618         return 0;
 619
 620 clear_hash:
 621         tcp_put_md5sig_pool();
 622 clear_hash_noput:
 623         memset(md5_hash, 0, 16);
 624         return 1;
 625 }
 626
 627 static bool tcp_v6_inbound_md5_hash(struct sock *sk, const struct sk_buff *skb)
 628 {
 629         const __u8 *hash_location = NULL;
 630         struct tcp_md5sig_key *hash_expected;
 631         const struct ipv6hdr *ip6h = ipv6_hdr(skb);
 632         const struct tcphdr *th = tcp_hdr(skb);
 633         int genhash;
 634         u8 newhash[16];
 635
 636         hash_expected = tcp_v6_md5_do_lookup(sk, &ip6h->saddr);
 637         hash_location = tcp_parse_md5sig_option(th);
 638
 639         /* We've parsed the options - do we have a hash? */
 640         if (!hash_expected && !hash_location)
 641                 return false;
 642
 643         if (hash_expected && !hash_location) {
 644                 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5NOTFOUND);
 645                 return true;
 646         }
 647
 648         if (!hash_expected && hash_location) {
 649                 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5UNEXPECTED);
 650                 return true;
 651         }
 652
 653         /* check the signature */
 654         genhash = tcp_v6_md5_hash_skb(newhash,
 655                                       hash_expected,
 656                                       NULL, skb);
 657
 658         if (genhash || memcmp(hash_location, newhash, 16) != 0) {
 659                 net_info_ratelimited("MD5 Hash %s for [%pI6c]:%u->[%pI6c]:%u\n",
 660                                      genhash ? "failed" : "mismatch",
 661                                      &ip6h->saddr, ntohs(th->source),
 662                                      &ip6h->daddr, ntohs(th->dest));
 663                 return true;
 664         }
 665         return false;
 666 }
 667 #endif
 668
 669 static void tcp_v6_init_req(struct request_sock *req, struct sock *sk,
 670                             struct sk_buff *skb)
 671 {
 672         struct inet_request_sock *ireq = inet_rsk(req);
 673         struct ipv6_pinfo *np = inet6_sk(sk);
 674
 675         ireq->ir_v6_rmt_addr = ipv6_hdr(skb)->saddr;
 676         ireq->ir_v6_loc_addr = ipv6_hdr(skb)->daddr;
 677
 678         /* So that link locals have meaning */
 679         if (!sk->sk_bound_dev_if &&
 680             ipv6_addr_type(&ireq->ir_v6_rmt_addr) & IPV6_ADDR_LINKLOCAL)
 681                 ireq->ir_iif = tcp_v6_iif(skb);
 682
 683         if (!TCP_SKB_CB(skb)->tcp_tw_isn &&
 684             (ipv6_opt_accepted(sk, skb, &TCP_SKB_CB(skb)->header.h6) ||
 685              np->rxopt.bits.rxinfo ||
 686              np->rxopt.bits.rxoinfo || np->rxopt.bits.rxhlim ||
 687              np->rxopt.bits.rxohlim || np->repflow)) {
 688                 atomic_inc(&skb->users);
 689                 ireq->pktopts = skb;
 690         }
 691 }
 692
 693 static struct dst_entry *tcp_v6_route_req(struct sock *sk, struct flowi *fl,
 694                                           const struct request_sock *req,
 695                                           bool *strict)
 696 {
 697         if (strict)
 698                 *strict = true;
 699         return inet6_csk_route_req(sk, &fl->u.ip6, req);
 700 }
 701
 702 struct request_sock_ops tcp6_request_sock_ops __read_mostly = {
 703         .family         =       AF_INET6,
 704         .obj_size       =       sizeof(struct tcp6_request_sock),
 705         .rtx_syn_ack    =       tcp_rtx_synack,
 706         .send_ack       =       tcp_v6_reqsk_send_ack,
 707         .destructor     =       tcp_v6_reqsk_destructor,
 708         .send_reset     =       tcp_v6_send_reset,
 709         .syn_ack_timeout =      tcp_syn_ack_timeout,
 710 };
 711
 712 static const struct tcp_request_sock_ops tcp_request_sock_ipv6_ops = {
 713         .mss_clamp      =       IPV6_MIN_MTU - sizeof(struct tcphdr) -
 714                                 sizeof(struct ipv6hdr),
 715 #ifdef CONFIG_TCP_MD5SIG
 716         .req_md5_lookup =       tcp_v6_md5_lookup,
 717         .calc_md5_hash  =       tcp_v6_md5_hash_skb,
 718 #endif
 719         .init_req       =       tcp_v6_init_req,
 720 #ifdef CONFIG_SYN_COOKIES
 721         .cookie_init_seq =      cookie_v6_init_sequence,
 722 #endif
 723         .route_req      =       tcp_v6_route_req,
 724         .init_seq       =       tcp_v6_init_sequence,
 725         .send_synack    =       tcp_v6_send_synack,
 726         .queue_hash_add =       inet6_csk_reqsk_queue_hash_add,
 727 };
 728
 729 static void tcp_v6_send_response(struct sock *sk, struct sk_buff *skb, u32 seq,
 730                                  u32 ack, u32 win, u32 tsval, u32 tsecr,
 731                                  int oif, struct tcp_md5sig_key *key, int rst,
 732                                  u8 tclass, u32 label)
 733 {
 734         const struct tcphdr *th = tcp_hdr(skb);
 735         struct tcphdr *t1;
 736         struct sk_buff *buff;
 737         struct flowi6 fl6;
 738         struct net *net = sk ? sock_net(sk) : dev_net(skb_dst(skb)->dev);
 739         struct sock *ctl_sk = net->ipv6.tcp_sk;
 740         unsigned int tot_len = sizeof(struct tcphdr);
 741         struct dst_entry *dst;
 742         __be32 *topt;
 743
 744         if (tsecr)
 745                 tot_len += TCPOLEN_TSTAMP_ALIGNED;
 746 #ifdef CONFIG_TCP_MD5SIG
 747         if (key)
 748                 tot_len += TCPOLEN_MD5SIG_ALIGNED;
 749 #endif
 750
 751         buff = alloc_skb(MAX_HEADER + sizeof(struct ipv6hdr) + tot_len,
 752                          GFP_ATOMIC);
 753         if (!buff)
 754                 return;
 755
 756         skb_reserve(buff, MAX_HEADER + sizeof(struct ipv6hdr) + tot_len);
 757
 758         t1 = (struct tcphdr *) skb_push(buff, tot_len);
 759         skb_reset_transport_header(buff);
 760
 761         /* Swap the send and the receive. */
 762         memset(t1, 0, sizeof(*t1));
 763         t1->dest = th->source;
 764         t1->source = th->dest;
 765         t1->doff = tot_len / 4;
 766         t1->seq = htonl(seq);
 767         t1->ack_seq = htonl(ack);
 768         t1->ack = !rst || !th->ack;
 769         t1->rst = rst;
 770         t1->window = htons(win);
 771
 772         topt = (__be32 *)(t1 + 1);
 773
 774         if (tsecr) {
 775                 *topt++ = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
 776                                 (TCPOPT_TIMESTAMP << 8) | TCPOLEN_TIMESTAMP);
 777                 *topt++ = htonl(tsval);
 778                 *topt++ = htonl(tsecr);
 779         }
 780
 781 #ifdef CONFIG_TCP_MD5SIG
 782         if (key) {
 783                 *topt++ = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
 784                                 (TCPOPT_MD5SIG << 8) | TCPOLEN_MD5SIG);
 785                 tcp_v6_md5_hash_hdr((__u8 *)topt, key,
 786                                     &ipv6_hdr(skb)->saddr,
 787                                     &ipv6_hdr(skb)->daddr, t1);
 788         }
 789 #endif
 790
 791         memset(&fl6, 0, sizeof(fl6));
 792         fl6.daddr = ipv6_hdr(skb)->saddr;
 793         fl6.saddr = ipv6_hdr(skb)->daddr;
 794         fl6.flowlabel = label;
 795
 796         buff->ip_summed = CHECKSUM_PARTIAL;
 797         buff->csum = 0;
 798
 799         __tcp_v6_send_check(buff, &fl6.saddr, &fl6.daddr);
 800
 801         fl6.flowi6_proto = IPPROTO_TCP;
 802         if (rt6_need_strict(&fl6.daddr) && !oif)
 803                 fl6.flowi6_oif = tcp_v6_iif(skb);
 804         else
 805                 fl6.flowi6_oif = oif;
 806         fl6.flowi6_mark = IP6_REPLY_MARK(net, skb->mark);
 807         fl6.fl6_dport = t1->dest;
 808         fl6.fl6_sport = t1->source;
 809         security_skb_classify_flow(skb, flowi6_to_flowi(&fl6));
 810
 811         /* Pass a socket to ip6_dst_lookup either it is for RST
 812          * Underlying function will use this to retrieve the network
 813          * namespace
 814          */
 815         dst = ip6_dst_lookup_flow(ctl_sk, &fl6, NULL);
 816         if (!IS_ERR(dst)) {
 817                 skb_dst_set(buff, dst);
 818                 ip6_xmit(ctl_sk, buff, &fl6, NULL, tclass);
 819                 TCP_INC_STATS_BH(net, TCP_MIB_OUTSEGS);
 820                 if (rst)
 821                         TCP_INC_STATS_BH(net, TCP_MIB_OUTRSTS);
 822                 return;
 823         }
 824
 825         kfree_skb(buff);
 826 }
 827
 828 static void tcp_v6_send_reset(struct sock *sk, struct sk_buff *skb)
 829 {
 830         const struct tcphdr *th = tcp_hdr(skb);
 831         u32 seq = 0, ack_seq = 0;
 832         struct tcp_md5sig_key *key = NULL;
 833 #ifdef CONFIG_TCP_MD5SIG
 834         const __u8 *hash_location = NULL;
 835         struct ipv6hdr *ipv6h = ipv6_hdr(skb);
 836         unsigned char newhash[16];
 837         int genhash;
 838         struct sock *sk1 = NULL;
 839 #endif
 840         int oif;
 841
 842         if (th->rst)
 843                 return;
 844
 845         /* If sk not NULL, it means we did a successful lookup and incoming
 846          * route had to be correct. prequeue might have dropped our dst.
 847          */
 848         if (!sk && !ipv6_unicast_destination(skb))
 849                 return;
 850
 851 #ifdef CONFIG_TCP_MD5SIG
 852         hash_location = tcp_parse_md5sig_option(th);
 853         if (!sk && hash_location) {
 854                 /*
 855                  * active side is lost. Try to find listening socket through
 856                  * source port, and then find md5 key through listening socket.
 857                  * we are not loose security here:
 858                  * Incoming packet is checked with md5 hash with finding key,
 859                  * no RST generated if md5 hash doesn't match.
 860                  */
 861                 sk1 = inet6_lookup_listener(dev_net(skb_dst(skb)->dev),
 862                                            &tcp_hashinfo, &ipv6h->saddr,
 863                                            th->source, &ipv6h->daddr,
 864                                            ntohs(th->source), tcp_v6_iif(skb));
 865                 if (!sk1)
 866                         return;
 867
 868                 rcu_read_lock();
 869                 key = tcp_v6_md5_do_lookup(sk1, &ipv6h->saddr);
 870                 if (!key)
 871                         goto release_sk1;
 872
 873                 genhash = tcp_v6_md5_hash_skb(newhash, key, NULL, skb);
 874                 if (genhash || memcmp(hash_location, newhash, 16) != 0)
 875                         goto release_sk1;
 876         } else {
 877                 key = sk ? tcp_v6_md5_do_lookup(sk, &ipv6h->saddr) : NULL;
 878         }
 879 #endif
 880
 881         if (th->ack)
 882                 seq = ntohl(th->ack_seq);
 883         else
 884                 ack_seq = ntohl(th->seq) + th->syn + th->fin + skb->len -
 885                           (th->doff << 2);
 886
 887         oif = sk ? sk->sk_bound_dev_if : 0;
 888         tcp_v6_send_response(sk, skb, seq, ack_seq, 0, 0, 0, oif, key, 1, 0, 0);
 889
 890 #ifdef CONFIG_TCP_MD5SIG
 891 release_sk1:
 892         if (sk1) {
 893                 rcu_read_unlock();
 894                 sock_put(sk1);
 895         }
 896 #endif
 897 }
 898
 899 static void tcp_v6_send_ack(struct sock *sk, struct sk_buff *skb, u32 seq,
 900                             u32 ack, u32 win, u32 tsval, u32 tsecr, int oif,
 901                             struct tcp_md5sig_key *key, u8 tclass,
 902                             u32 label)
 903 {
 904         tcp_v6_send_response(sk, skb, seq, ack, win, tsval, tsecr, oif, key, 0,
 905                              tclass, label);
 906 }
 907
 908 static void tcp_v6_timewait_ack(struct sock *sk, struct sk_buff *skb)
 909 {
 910         struct inet_timewait_sock *tw = inet_twsk(sk);
 911         struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
 912
 913         tcp_v6_send_ack(sk, skb, tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
 914                         tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
 915                         tcp_time_stamp + tcptw->tw_ts_offset,
 916                         tcptw->tw_ts_recent, tw->tw_bound_dev_if, tcp_twsk_md5_key(tcptw),
 917                         tw->tw_tclass, (tw->tw_flowlabel << 12));
 918
 919         inet_twsk_put(tw);
 920 }
 921
 922 static void tcp_v6_reqsk_send_ack(struct sock *sk, struct sk_buff *skb,
 923                                   struct request_sock *req)
 924 {
 925         /* sk->sk_state == TCP_LISTEN -> for regular TCP_SYN_RECV
 926          * sk->sk_state == TCP_SYN_RECV -> for Fast Open.
 927          */
 928         tcp_v6_send_ack(sk, skb, (sk->sk_state == TCP_LISTEN) ?
 929                         tcp_rsk(req)->snt_isn + 1 : tcp_sk(sk)->snd_nxt,
 930                         tcp_rsk(req)->rcv_nxt, req->rcv_wnd,
 931                         tcp_time_stamp, req->ts_recent, sk->sk_bound_dev_if,
 932                         tcp_v6_md5_do_lookup(sk, &ipv6_hdr(skb)->daddr),
 933                         0, 0);
 934 }
 935
 936
 937 static struct sock *tcp_v6_hnd_req(struct sock *sk, struct sk_buff *skb)
 938 {
 939         const struct tcphdr *th = tcp_hdr(skb);
 940         struct request_sock *req;
 941         struct sock *nsk;
 942
 943         /* Find possible connection requests. */
 944         req = inet6_csk_search_req(sk, th->source,
 945                                    &ipv6_hdr(skb)->saddr,
 946                                    &ipv6_hdr(skb)->daddr, tcp_v6_iif(skb));
 947         if (req) {
 948                 nsk = tcp_check_req(sk, skb, req, false);
 949                 reqsk_put(req);
 950                 return nsk;
 951         }
 952         nsk = __inet6_lookup_established(sock_net(sk), &tcp_hashinfo,
 953                                          &ipv6_hdr(skb)->saddr, th->source,
 954                                          &ipv6_hdr(skb)->daddr, ntohs(th->dest),
 955                                          tcp_v6_iif(skb));
 956
 957         if (nsk) {
 958                 if (nsk->sk_state != TCP_TIME_WAIT) {
 959                         bh_lock_sock(nsk);
 960                         return nsk;
 961                 }
 962                 inet_twsk_put(inet_twsk(nsk));
 963                 return NULL;
 964         }
 965
 966 #ifdef CONFIG_SYN_COOKIES
 967         if (!th->syn)
 968                 sk = cookie_v6_check(sk, skb);
 969 #endif
 970         return sk;
 971 }
 972
 973 static int tcp_v6_conn_request(struct sock *sk, struct sk_buff *skb)
 974 {
 975         if (skb->protocol == htons(ETH_P_IP))
 976                 return tcp_v4_conn_request(sk, skb);
 977
 978         if (!ipv6_unicast_destination(skb))
 979                 goto drop;
 980
 981         return tcp_conn_request(&tcp6_request_sock_ops,
 982                                 &tcp_request_sock_ipv6_ops, sk, skb);
 983
 984 drop:
 985         NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
 986         return 0; /* don't send reset */
 987 }
 988
 989 static struct sock *tcp_v6_syn_recv_sock(struct sock *sk, struct sk_buff *skb,
 990                                          struct request_sock *req,
 991                                          struct dst_entry *dst)
 992 {
 993         struct inet_request_sock *ireq;
 994         struct ipv6_pinfo *newnp, *np = inet6_sk(sk);
 995         struct tcp6_sock *newtcp6sk;
 996         struct inet_sock *newinet;
 997         struct tcp_sock *newtp;
 998         struct sock *newsk;
 999 #ifdef CONFIG_TCP_MD5SIG
1000         struct tcp_md5sig_key *key;
1001 #endif
1002         struct flowi6 fl6;
1003
1004         if (skb->protocol == htons(ETH_P_IP)) {
1005                 /*
1006                  *      v6 mapped
1007                  */
1008
1009                 newsk = tcp_v4_syn_recv_sock(sk, skb, req, dst);
1010
1011                 if (!newsk)
1012                         return NULL;
1013
1014                 newtcp6sk = (struct tcp6_sock *)newsk;
1015                 inet_sk(newsk)->pinet6 = &newtcp6sk->inet6;
1016
1017                 newinet = inet_sk(newsk);
1018                 newnp = inet6_sk(newsk);
1019                 newtp = tcp_sk(newsk);
1020
1021                 memcpy(newnp, np, sizeof(struct ipv6_pinfo));
1022
1023                 newnp->saddr = newsk->sk_v6_rcv_saddr;
1024
1025                 inet_csk(newsk)->icsk_af_ops = &ipv6_mapped;
1026                 newsk->sk_backlog_rcv = tcp_v4_do_rcv;
1027 #ifdef CONFIG_TCP_MD5SIG
1028                 newtp->af_specific = &tcp_sock_ipv6_mapped_specific;
1029 #endif
1030
1031                 newnp->ipv6_ac_list = NULL;
1032                 newnp->ipv6_fl_list = NULL;
1033                 newnp->pktoptions  = NULL;
1034                 newnp->opt         = NULL;
1035                 newnp->mcast_oif   = tcp_v6_iif(skb);
1036                 newnp->mcast_hops  = ipv6_hdr(skb)->hop_limit;
1037                 newnp->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(skb));
1038                 if (np->repflow)
1039                         newnp->flow_label = ip6_flowlabel(ipv6_hdr(skb));
1040
1041                 /*
1042                  * No need to charge this sock to the relevant IPv6 refcnt debug socks count
1043                  * here, tcp_create_openreq_child now does this for us, see the comment in
1044                  * that function for the gory details. -acme
1045                  */
1046
1047                 /* It is tricky place. Until this moment IPv4 tcp
1048                    worked with IPv6 icsk.icsk_af_ops.
1049                    Sync it now.
1050                  */
1051                 tcp_sync_mss(newsk, inet_csk(newsk)->icsk_pmtu_cookie);
1052
1053                 return newsk;
1054         }
1055
1056         ireq = inet_rsk(req);
1057
1058         if (sk_acceptq_is_full(sk))
1059                 goto out_overflow;
1060
1061         if (!dst) {
1062                 dst = inet6_csk_route_req(sk, &fl6, req);
1063                 if (!dst)
1064                         goto out;
1065         }
1066
1067         newsk = tcp_create_openreq_child(sk, req, skb);
1068         if (!newsk)
1069                 goto out_nonewsk;
1070
1071         /*
1072          * No need to charge this sock to the relevant IPv6 refcnt debug socks
1073          * count here, tcp_create_openreq_child now does this for us, see the
1074          * comment in that function for the gory details. -acme
1075          */
1076
1077         newsk->sk_gso_type = SKB_GSO_TCPV6;
1078         __ip6_dst_store(newsk, dst, NULL, NULL);
1079         inet6_sk_rx_dst_set(newsk, skb);
1080
1081         newtcp6sk = (struct tcp6_sock *)newsk;
1082         inet_sk(newsk)->pinet6 = &newtcp6sk->inet6;
1083
1084         newtp = tcp_sk(newsk);
1085         newinet = inet_sk(newsk);
1086         newnp = inet6_sk(newsk);
1087
1088         memcpy(newnp, np, sizeof(struct ipv6_pinfo));
1089
1090         newsk->sk_v6_daddr = ireq->ir_v6_rmt_addr;
1091         newnp->saddr = ireq->ir_v6_loc_addr;
1092         newsk->sk_v6_rcv_saddr = ireq->ir_v6_loc_addr;
1093         newsk->sk_bound_dev_if = ireq->ir_iif;
1094
1095         ip6_set_txhash(newsk);
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         /* Clone pktoptions received with SYN */
1109         newnp->pktoptions = NULL;
1110         if (ireq->pktopts) {
1111                 newnp->pktoptions = skb_clone(ireq->pktopts,
1112                                               sk_gfp_atomic(sk, GFP_ATOMIC));
1113                 consume_skb(ireq->pktopts);
1114                 ireq->pktopts = NULL;
1115                 if (newnp->pktoptions)
1116                         skb_set_owner_r(newnp->pktoptions, newsk);
1117         }
1118         newnp->opt        = NULL;
1119         newnp->mcast_oif  = tcp_v6_iif(skb);
1120         newnp->mcast_hops = ipv6_hdr(skb)->hop_limit;
1121         newnp->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(skb));
1122         if (np->repflow)
1123                 newnp->flow_label = ip6_flowlabel(ipv6_hdr(skb));
1124
1125         /* Clone native IPv6 options from listening socket (if any)
1126
1127            Yes, keeping reference count would be much more clever,
1128            but we make one more one thing there: reattach optmem
1129            to newsk.
1130          */
1131         if (np->opt)
1132                 newnp->opt = ipv6_dup_options(newsk, np->opt);
1133
1134         inet_csk(newsk)->icsk_ext_hdr_len = 0;
1135         if (newnp->opt)
1136                 inet_csk(newsk)->icsk_ext_hdr_len = (newnp->opt->opt_nflen +
1137                                                      newnp->opt->opt_flen);
1138
1139         tcp_ca_openreq_child(newsk, dst);
1140
1141         tcp_sync_mss(newsk, dst_mtu(dst));
1142         newtp->advmss = dst_metric_advmss(dst);
1143         if (tcp_sk(sk)->rx_opt.user_mss &&
1144             tcp_sk(sk)->rx_opt.user_mss < newtp->advmss)
1145                 newtp->advmss = tcp_sk(sk)->rx_opt.user_mss;
1146
1147         tcp_initialize_rcv_mss(newsk);
1148
1149         newinet->inet_daddr = newinet->inet_saddr = LOOPBACK4_IPV6;
1150         newinet->inet_rcv_saddr = LOOPBACK4_IPV6;
1151
1152 #ifdef CONFIG_TCP_MD5SIG
1153         /* Copy over the MD5 key from the original socket */
1154         key = tcp_v6_md5_do_lookup(sk, &newsk->sk_v6_daddr);
1155         if (key) {
1156                 /* We're using one, so create a matching key
1157                  * on the newsk structure. If we fail to get
1158                  * memory, then we end up not copying the key
1159                  * across. Shucks.
1160                  */
1161                 tcp_md5_do_add(newsk, (union tcp_md5_addr *)&newsk->sk_v6_daddr,
1162                                AF_INET6, key->key, key->keylen,
1163                                sk_gfp_atomic(sk, GFP_ATOMIC));
1164         }
1165 #endif
1166
1167         if (__inet_inherit_port(sk, newsk) < 0) {
1168                 inet_csk_prepare_forced_close(newsk);
1169                 tcp_done(newsk);
1170                 goto out;
1171         }
1172         __inet_hash(newsk, NULL);
1173
1174         return newsk;
1175
1176 out_overflow:
1177         NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
1178 out_nonewsk:
1179         dst_release(dst);
1180 out:
1181         NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
1182         return NULL;
1183 }
1184
1185 /* The socket must have it's spinlock held when we get
1186  * here.
1187  *
1188  * We have a potential double-lock case here, so even when
1189  * doing backlog processing we use the BH locking scheme.
1190  * This is because we cannot sleep with the original spinlock
1191  * held.
1192  */
1193 static int tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb)
1194 {
1195         struct ipv6_pinfo *np = inet6_sk(sk);
1196         struct tcp_sock *tp;
1197         struct sk_buff *opt_skb = NULL;
1198
1199         /* Imagine: socket is IPv6. IPv4 packet arrives,
1200            goes to IPv4 receive handler and backlogged.
1201            From backlog it always goes here. Kerboom...
1202            Fortunately, tcp_rcv_established and rcv_established
1203            handle them correctly, but it is not case with
1204            tcp_v6_hnd_req and tcp_v6_send_reset().   --ANK
1205          */
1206
1207         if (skb->protocol == htons(ETH_P_IP))
1208                 return tcp_v4_do_rcv(sk, skb);
1209
1210         if (sk_filter(sk, skb))
1211                 goto discard;
1212
1213         /*
1214          *      socket locking is here for SMP purposes as backlog rcv
1215          *      is currently called with bh processing disabled.
1216          */
1217
1218         /* Do Stevens' IPV6_PKTOPTIONS.
1219
1220            Yes, guys, it is the only place in our code, where we
1221            may make it not affecting IPv4.
1222            The rest of code is protocol independent,
1223            and I do not like idea to uglify IPv4.
1224
1225            Actually, all the idea behind IPV6_PKTOPTIONS
1226            looks not very well thought. For now we latch
1227            options, received in the last packet, enqueued
1228            by tcp. Feel free to propose better solution.
1229                                                --ANK (980728)
1230          */
1231         if (np->rxopt.all)
1232                 opt_skb = skb_clone(skb, sk_gfp_atomic(sk, GFP_ATOMIC));
1233
1234         if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
1235                 struct dst_entry *dst = sk->sk_rx_dst;
1236
1237                 sock_rps_save_rxhash(sk, skb);
1238                 sk_mark_napi_id(sk, skb);
1239                 if (dst) {
1240                         if (inet_sk(sk)->rx_dst_ifindex != skb->skb_iif ||
1241                             dst->ops->check(dst, np->rx_dst_cookie) == NULL) {
1242                                 dst_release(dst);
1243                                 sk->sk_rx_dst = NULL;
1244                         }
1245                 }
1246
1247                 tcp_rcv_established(sk, skb, tcp_hdr(skb), skb->len);
1248                 if (opt_skb)
1249                         goto ipv6_pktoptions;
1250                 return 0;
1251         }
1252
1253         if (skb->len < tcp_hdrlen(skb) || tcp_checksum_complete(skb))
1254                 goto csum_err;
1255
1256         if (sk->sk_state == TCP_LISTEN) {
1257                 struct sock *nsk = tcp_v6_hnd_req(sk, skb);
1258                 if (!nsk)
1259                         goto discard;
1260
1261                 /*
1262                  * Queue it on the new socket if the new socket is active,
1263                  * otherwise we just shortcircuit this and continue with
1264                  * the new socket..
1265                  */
1266                 if (nsk != sk) {
1267                         sock_rps_save_rxhash(nsk, skb);
1268                         sk_mark_napi_id(sk, skb);
1269                         if (tcp_child_process(sk, nsk, skb))
1270                                 goto reset;
1271                         if (opt_skb)
1272                                 __kfree_skb(opt_skb);
1273                         return 0;
1274                 }
1275         } else
1276                 sock_rps_save_rxhash(sk, skb);
1277
1278         if (tcp_rcv_state_process(sk, skb, tcp_hdr(skb), skb->len))
1279                 goto reset;
1280         if (opt_skb)
1281                 goto ipv6_pktoptions;
1282         return 0;
1283
1284 reset:
1285         tcp_v6_send_reset(sk, skb);
1286 discard:
1287         if (opt_skb)
1288                 __kfree_skb(opt_skb);
1289         kfree_skb(skb);
1290         return 0;
1291 csum_err:
1292         TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_CSUMERRORS);
1293         TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_INERRS);
1294         goto discard;
1295
1296
1297 ipv6_pktoptions:
1298         /* Do you ask, what is it?
1299
1300            1. skb was enqueued by tcp.
1301            2. skb is added to tail of read queue, rather than out of order.
1302            3. socket is not in passive state.
1303            4. Finally, it really contains options, which user wants to receive.
1304          */
1305         tp = tcp_sk(sk);
1306         if (TCP_SKB_CB(opt_skb)->end_seq == tp->rcv_nxt &&
1307             !((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN))) {
1308                 if (np->rxopt.bits.rxinfo || np->rxopt.bits.rxoinfo)
1309                         np->mcast_oif = tcp_v6_iif(opt_skb);
1310                 if (np->rxopt.bits.rxhlim || np->rxopt.bits.rxohlim)
1311                         np->mcast_hops = ipv6_hdr(opt_skb)->hop_limit;
1312                 if (np->rxopt.bits.rxflow || np->rxopt.bits.rxtclass)
1313                         np->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(opt_skb));
1314                 if (np->repflow)
1315                         np->flow_label = ip6_flowlabel(ipv6_hdr(opt_skb));
1316                 if (ipv6_opt_accepted(sk, opt_skb, &TCP_SKB_CB(opt_skb)->header.h6)) {
1317                         skb_set_owner_r(opt_skb, sk);
1318                         opt_skb = xchg(&np->pktoptions, opt_skb);
1319                 } else {
1320                         __kfree_skb(opt_skb);
1321                         opt_skb = xchg(&np->pktoptions, NULL);
1322                 }
1323         }
1324
1325         kfree_skb(opt_skb);
1326         return 0;
1327 }
1328
1329 static void tcp_v6_fill_cb(struct sk_buff *skb, const struct ipv6hdr *hdr,
1330                            const struct tcphdr *th)
1331 {
1332         /* This is tricky: we move IP6CB at its correct location into
1333          * TCP_SKB_CB(). It must be done after xfrm6_policy_check(), because
1334          * _decode_session6() uses IP6CB().
1335          * barrier() makes sure compiler won't play aliasing games.
1336          */
1337         memmove(&TCP_SKB_CB(skb)->header.h6, IP6CB(skb),
1338                 sizeof(struct inet6_skb_parm));
1339         barrier();
1340
1341         TCP_SKB_CB(skb)->seq = ntohl(th->seq);
1342         TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
1343                                     skb->len - th->doff*4);
1344         TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
1345         TCP_SKB_CB(skb)->tcp_flags = tcp_flag_byte(th);
1346         TCP_SKB_CB(skb)->tcp_tw_isn = 0;
1347         TCP_SKB_CB(skb)->ip_dsfield = ipv6_get_dsfield(hdr);
1348         TCP_SKB_CB(skb)->sacked = 0;
1349 }
1350
1351 static void tcp_v6_restore_cb(struct sk_buff *skb)
1352 {
1353         /* We need to move header back to the beginning if xfrm6_policy_check()
1354          * and tcp_v6_fill_cb() are going to be called again.
1355          */
1356         memmove(IP6CB(skb), &TCP_SKB_CB(skb)->header.h6,
1357                 sizeof(struct inet6_skb_parm));
1358 }
1359
1360 static int tcp_v6_rcv(struct sk_buff *skb)
1361 {
1362         const struct tcphdr *th;
1363         const struct ipv6hdr *hdr;
1364         struct sock *sk;
1365         int ret;
1366         struct net *net = dev_net(skb->dev);
1367
1368         if (skb->pkt_type != PACKET_HOST)
1369                 goto discard_it;
1370
1371         /*
1372          *      Count it even if it's bad.
1373          */
1374         TCP_INC_STATS_BH(net, TCP_MIB_INSEGS);
1375
1376         if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
1377                 goto discard_it;
1378
1379         th = tcp_hdr(skb);
1380
1381         if (th->doff < sizeof(struct tcphdr)/4)
1382                 goto bad_packet;
1383         if (!pskb_may_pull(skb, th->doff*4))
1384                 goto discard_it;
1385
1386         if (skb_checksum_init(skb, IPPROTO_TCP, ip6_compute_pseudo))
1387                 goto csum_error;
1388
1389         th = tcp_hdr(skb);
1390         hdr = ipv6_hdr(skb);
1391
1392         sk = __inet6_lookup_skb(&tcp_hashinfo, skb, th->source, th->dest,
1393                                 inet6_iif(skb));
1394         if (!sk)
1395                 goto no_tcp_socket;
1396
1397 process:
1398         if (sk->sk_state == TCP_TIME_WAIT)
1399                 goto do_time_wait;
1400
1401         if (hdr->hop_limit < inet6_sk(sk)->min_hopcount) {
1402                 NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP);
1403                 goto discard_and_relse;
1404         }
1405
1406         if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb))
1407                 goto discard_and_relse;
1408
1409         tcp_v6_fill_cb(skb, hdr, th);
1410
1411 #ifdef CONFIG_TCP_MD5SIG
1412         if (tcp_v6_inbound_md5_hash(sk, skb))
1413                 goto discard_and_relse;
1414 #endif
1415
1416         if (sk_filter(sk, skb))
1417                 goto discard_and_relse;
1418
1419         sk_incoming_cpu_update(sk);
1420         skb->dev = NULL;
1421
1422         bh_lock_sock_nested(sk);
1423         ret = 0;
1424         if (!sock_owned_by_user(sk)) {
1425                 if (!tcp_prequeue(sk, skb))
1426                         ret = tcp_v6_do_rcv(sk, skb);
1427         } else if (unlikely(sk_add_backlog(sk, skb,
1428                                            sk->sk_rcvbuf + sk->sk_sndbuf))) {
1429                 bh_unlock_sock(sk);
1430                 NET_INC_STATS_BH(net, LINUX_MIB_TCPBACKLOGDROP);
1431                 goto discard_and_relse;
1432         }
1433         bh_unlock_sock(sk);
1434
1435         sock_put(sk);
1436         return ret ? -1 : 0;
1437
1438 no_tcp_socket:
1439         if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb))
1440                 goto discard_it;
1441
1442         tcp_v6_fill_cb(skb, hdr, th);
1443
1444         if (skb->len < (th->doff<<2) || tcp_checksum_complete(skb)) {
1445 csum_error:
1446                 TCP_INC_STATS_BH(net, TCP_MIB_CSUMERRORS);
1447 bad_packet:
1448                 TCP_INC_STATS_BH(net, TCP_MIB_INERRS);
1449         } else {
1450                 tcp_v6_send_reset(NULL, skb);
1451         }
1452
1453 discard_it:
1454         kfree_skb(skb);
1455         return 0;
1456
1457 discard_and_relse:
1458         sock_put(sk);
1459         goto discard_it;
1460
1461 do_time_wait:
1462         if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
1463                 inet_twsk_put(inet_twsk(sk));
1464                 goto discard_it;
1465         }
1466
1467         tcp_v6_fill_cb(skb, hdr, th);
1468
1469         if (skb->len < (th->doff<<2)) {
1470                 inet_twsk_put(inet_twsk(sk));
1471                 goto bad_packet;
1472         }
1473         if (tcp_checksum_complete(skb)) {
1474                 inet_twsk_put(inet_twsk(sk));
1475                 goto csum_error;
1476         }
1477
1478         switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) {
1479         case TCP_TW_SYN:
1480         {
1481                 struct sock *sk2;
1482
1483                 sk2 = inet6_lookup_listener(dev_net(skb->dev), &tcp_hashinfo,
1484                                             &ipv6_hdr(skb)->saddr, th->source,
1485                                             &ipv6_hdr(skb)->daddr,
1486                                             ntohs(th->dest), tcp_v6_iif(skb));
1487                 if (sk2) {
1488                         struct inet_timewait_sock *tw = inet_twsk(sk);
1489                         inet_twsk_deschedule(tw);
1490                         inet_twsk_put(tw);
1491                         sk = sk2;
1492                         tcp_v6_restore_cb(skb);
1493                         goto process;
1494                 }
1495                 /* Fall through to ACK */
1496         }
1497         case TCP_TW_ACK:
1498                 tcp_v6_timewait_ack(sk, skb);
1499                 break;
1500         case TCP_TW_RST:
1501                 tcp_v6_restore_cb(skb);
1502                 goto no_tcp_socket;
1503         case TCP_TW_SUCCESS:
1504                 ;
1505         }
1506         goto discard_it;
1507 }
1508
1509 static void tcp_v6_early_demux(struct sk_buff *skb)
1510 {
1511         const struct ipv6hdr *hdr;
1512         const struct tcphdr *th;
1513         struct sock *sk;
1514
1515         if (skb->pkt_type != PACKET_HOST)
1516                 return;
1517
1518         if (!pskb_may_pull(skb, skb_transport_offset(skb) + sizeof(struct tcphdr)))
1519                 return;
1520
1521         hdr = ipv6_hdr(skb);
1522         th = tcp_hdr(skb);
1523
1524         if (th->doff < sizeof(struct tcphdr) / 4)
1525                 return;
1526
1527         /* Note : We use inet6_iif() here, not tcp_v6_iif() */
1528         sk = __inet6_lookup_established(dev_net(skb->dev), &tcp_hashinfo,
1529                                         &hdr->saddr, th->source,
1530                                         &hdr->daddr, ntohs(th->dest),
1531                                         inet6_iif(skb));
1532         if (sk) {
1533                 skb->sk = sk;
1534                 skb->destructor = sock_edemux;
1535                 if (sk_fullsock(sk)) {
1536                         struct dst_entry *dst = READ_ONCE(sk->sk_rx_dst);
1537
1538                         if (dst)
1539                                 dst = dst_check(dst, inet6_sk(sk)->rx_dst_cookie);
1540                         if (dst &&
1541                             inet_sk(sk)->rx_dst_ifindex == skb->skb_iif)
1542                                 skb_dst_set_noref(skb, dst);
1543                 }
1544         }
1545 }
1546
1547 static struct timewait_sock_ops tcp6_timewait_sock_ops = {
1548         .twsk_obj_size  = sizeof(struct tcp6_timewait_sock),
1549         .twsk_unique    = tcp_twsk_unique,
1550         .twsk_destructor = tcp_twsk_destructor,
1551 };
1552
1553 static const struct inet_connection_sock_af_ops ipv6_specific = {
1554         .queue_xmit        = inet6_csk_xmit,
1555         .send_check        = tcp_v6_send_check,
1556         .rebuild_header    = inet6_sk_rebuild_header,
1557         .sk_rx_dst_set     = inet6_sk_rx_dst_set,
1558         .conn_request      = tcp_v6_conn_request,
1559         .syn_recv_sock     = tcp_v6_syn_recv_sock,
1560         .net_header_len    = sizeof(struct ipv6hdr),
1561         .net_frag_header_len = sizeof(struct frag_hdr),
1562         .setsockopt        = ipv6_setsockopt,
1563         .getsockopt        = ipv6_getsockopt,
1564         .addr2sockaddr     = inet6_csk_addr2sockaddr,
1565         .sockaddr_len      = sizeof(struct sockaddr_in6),
1566         .bind_conflict     = inet6_csk_bind_conflict,
1567 #ifdef CONFIG_COMPAT
1568         .compat_setsockopt = compat_ipv6_setsockopt,
1569         .compat_getsockopt = compat_ipv6_getsockopt,
1570 #endif
1571         .mtu_reduced       = tcp_v6_mtu_reduced,
1572 };
1573
1574 #ifdef CONFIG_TCP_MD5SIG
1575 static const struct tcp_sock_af_ops tcp_sock_ipv6_specific = {
1576         .md5_lookup     =       tcp_v6_md5_lookup,
1577         .calc_md5_hash  =       tcp_v6_md5_hash_skb,
1578         .md5_parse      =       tcp_v6_parse_md5_keys,
1579 };
1580 #endif
1581
1582 /*
1583  *      TCP over IPv4 via INET6 API
1584  */
1585 static const struct inet_connection_sock_af_ops ipv6_mapped = {
1586         .queue_xmit        = ip_queue_xmit,
1587         .send_check        = tcp_v4_send_check,
1588         .rebuild_header    = inet_sk_rebuild_header,
1589         .sk_rx_dst_set     = inet_sk_rx_dst_set,
1590         .conn_request      = tcp_v6_conn_request,
1591         .syn_recv_sock     = tcp_v6_syn_recv_sock,
1592         .net_header_len    = sizeof(struct iphdr),
1593         .setsockopt        = ipv6_setsockopt,
1594         .getsockopt        = ipv6_getsockopt,
1595         .addr2sockaddr     = inet6_csk_addr2sockaddr,
1596         .sockaddr_len      = sizeof(struct sockaddr_in6),
1597         .bind_conflict     = inet6_csk_bind_conflict,
1598 #ifdef CONFIG_COMPAT
1599         .compat_setsockopt = compat_ipv6_setsockopt,
1600         .compat_getsockopt = compat_ipv6_getsockopt,
1601 #endif
1602         .mtu_reduced       = tcp_v4_mtu_reduced,
1603 };
1604
1605 #ifdef CONFIG_TCP_MD5SIG
1606 static const struct tcp_sock_af_ops tcp_sock_ipv6_mapped_specific = {
1607         .md5_lookup     =       tcp_v4_md5_lookup,
1608         .calc_md5_hash  =       tcp_v4_md5_hash_skb,
1609         .md5_parse      =       tcp_v6_parse_md5_keys,
1610 };
1611 #endif
1612
1613 /* NOTE: A lot of things set to zero explicitly by call to
1614  *       sk_alloc() so need not be done here.
1615  */
1616 static int tcp_v6_init_sock(struct sock *sk)
1617 {
1618         struct inet_connection_sock *icsk = inet_csk(sk);
1619
1620         tcp_init_sock(sk);
1621
1622         icsk->icsk_af_ops = &ipv6_specific;
1623
1624 #ifdef CONFIG_TCP_MD5SIG
1625         tcp_sk(sk)->af_specific = &tcp_sock_ipv6_specific;
1626 #endif
1627
1628         return 0;
1629 }
1630
1631 static void tcp_v6_destroy_sock(struct sock *sk)
1632 {
1633         tcp_v4_destroy_sock(sk);
1634         inet6_destroy_sock(sk);
1635 }
1636
1637 #ifdef CONFIG_PROC_FS
1638 /* Proc filesystem TCPv6 sock list dumping. */
1639 static void get_openreq6(struct seq_file *seq,
1640                          struct request_sock *req, int i, kuid_t uid)
1641 {
1642         long ttd = req->rsk_timer.expires - jiffies;
1643         const struct in6_addr *src = &inet_rsk(req)->ir_v6_loc_addr;
1644         const struct in6_addr *dest = &inet_rsk(req)->ir_v6_rmt_addr;
1645
1646         if (ttd < 0)
1647                 ttd = 0;
1648
1649         seq_printf(seq,
1650                    "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
1651                    "%02X %08X:%08X %02X:%08lX %08X %5u %8d %d %d %pK\n",
1652                    i,
1653                    src->s6_addr32[0], src->s6_addr32[1],
1654                    src->s6_addr32[2], src->s6_addr32[3],
1655                    inet_rsk(req)->ir_num,
1656                    dest->s6_addr32[0], dest->s6_addr32[1],
1657                    dest->s6_addr32[2], dest->s6_addr32[3],
1658                    ntohs(inet_rsk(req)->ir_rmt_port),
1659                    TCP_SYN_RECV,
1660                    0, 0, /* could print option size, but that is af dependent. */
1661                    1,   /* timers active (only the expire timer) */
1662                    jiffies_to_clock_t(ttd),
1663                    req->num_timeout,
1664                    from_kuid_munged(seq_user_ns(seq), uid),
1665                    0,  /* non standard timer */
1666                    0, /* open_requests have no inode */
1667                    0, req);
1668 }
1669
1670 static void get_tcp6_sock(struct seq_file *seq, struct sock *sp, int i)
1671 {
1672         const struct in6_addr *dest, *src;
1673         __u16 destp, srcp;
1674         int timer_active;
1675         unsigned long timer_expires;
1676         const struct inet_sock *inet = inet_sk(sp);
1677         const struct tcp_sock *tp = tcp_sk(sp);
1678         const struct inet_connection_sock *icsk = inet_csk(sp);
1679         struct fastopen_queue *fastopenq = icsk->icsk_accept_queue.fastopenq;
1680
1681         dest  = &sp->sk_v6_daddr;
1682         src   = &sp->sk_v6_rcv_saddr;
1683         destp = ntohs(inet->inet_dport);
1684         srcp  = ntohs(inet->inet_sport);
1685
1686         if (icsk->icsk_pending == ICSK_TIME_RETRANS) {
1687                 timer_active    = 1;
1688                 timer_expires   = icsk->icsk_timeout;
1689         } else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
1690                 timer_active    = 4;
1691                 timer_expires   = icsk->icsk_timeout;
1692         } else if (timer_pending(&sp->sk_timer)) {
1693                 timer_active    = 2;
1694                 timer_expires   = sp->sk_timer.expires;
1695         } else {
1696                 timer_active    = 0;
1697                 timer_expires = jiffies;
1698         }
1699
1700         seq_printf(seq,
1701                    "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
1702                    "%02X %08X:%08X %02X:%08lX %08X %5u %8d %lu %d %pK %lu %lu %u %u %d\n",
1703                    i,
1704                    src->s6_addr32[0], src->s6_addr32[1],
1705                    src->s6_addr32[2], src->s6_addr32[3], srcp,
1706                    dest->s6_addr32[0], dest->s6_addr32[1],
1707                    dest->s6_addr32[2], dest->s6_addr32[3], destp,
1708                    sp->sk_state,
1709                    tp->write_seq-tp->snd_una,
1710                    (sp->sk_state == TCP_LISTEN) ? sp->sk_ack_backlog : (tp->rcv_nxt - tp->copied_seq),
1711                    timer_active,
1712                    jiffies_delta_to_clock_t(timer_expires - jiffies),
1713                    icsk->icsk_retransmits,
1714                    from_kuid_munged(seq_user_ns(seq), sock_i_uid(sp)),
1715                    icsk->icsk_probes_out,
1716                    sock_i_ino(sp),
1717                    atomic_read(&sp->sk_refcnt), sp,
1718                    jiffies_to_clock_t(icsk->icsk_rto),
1719                    jiffies_to_clock_t(icsk->icsk_ack.ato),
1720                    (icsk->icsk_ack.quick << 1) | icsk->icsk_ack.pingpong,
1721                    tp->snd_cwnd,
1722                    sp->sk_state == TCP_LISTEN ?
1723                         (fastopenq ? fastopenq->max_qlen : 0) :
1724                         (tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh)
1725                    );
1726 }
1727
1728 static void get_timewait6_sock(struct seq_file *seq,
1729                                struct inet_timewait_sock *tw, int i)
1730 {
1731         long delta = tw->tw_timer.expires - jiffies;
1732         const struct in6_addr *dest, *src;
1733         __u16 destp, srcp;
1734
1735         dest = &tw->tw_v6_daddr;
1736         src  = &tw->tw_v6_rcv_saddr;
1737         destp = ntohs(tw->tw_dport);
1738         srcp  = ntohs(tw->tw_sport);
1739
1740         seq_printf(seq,
1741                    "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
1742                    "%02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK\n",
1743                    i,
1744                    src->s6_addr32[0], src->s6_addr32[1],
1745                    src->s6_addr32[2], src->s6_addr32[3], srcp,
1746                    dest->s6_addr32[0], dest->s6_addr32[1],
1747                    dest->s6_addr32[2], dest->s6_addr32[3], destp,
1748                    tw->tw_substate, 0, 0,
1749                    3, jiffies_delta_to_clock_t(delta), 0, 0, 0, 0,
1750                    atomic_read(&tw->tw_refcnt), tw);
1751 }
1752
1753 static int tcp6_seq_show(struct seq_file *seq, void *v)
1754 {
1755         struct tcp_iter_state *st;
1756         struct sock *sk = v;
1757
1758         if (v == SEQ_START_TOKEN) {
1759                 seq_puts(seq,
1760                          "  sl  "
1761                          "local_address                         "
1762                          "remote_address                        "
1763                          "st tx_queue rx_queue tr tm->when retrnsmt"
1764                          "   uid  timeout inode\n");
1765                 goto out;
1766         }
1767         st = seq->private;
1768
1769         switch (st->state) {
1770         case TCP_SEQ_STATE_LISTENING:
1771         case TCP_SEQ_STATE_ESTABLISHED:
1772                 if (sk->sk_state == TCP_TIME_WAIT)
1773                         get_timewait6_sock(seq, v, st->num);
1774                 else
1775                         get_tcp6_sock(seq, v, st->num);
1776                 break;
1777         case TCP_SEQ_STATE_OPENREQ:
1778                 get_openreq6(seq, v, st->num, st->uid);
1779                 break;
1780         }
1781 out:
1782         return 0;
1783 }
1784
1785 static const struct file_operations tcp6_afinfo_seq_fops = {
1786         .owner   = THIS_MODULE,
1787         .open    = tcp_seq_open,
1788         .read    = seq_read,
1789         .llseek  = seq_lseek,
1790         .release = seq_release_net
1791 };
1792
1793 static struct tcp_seq_afinfo tcp6_seq_afinfo = {
1794         .name           = "tcp6",
1795         .family         = AF_INET6,
1796         .seq_fops       = &tcp6_afinfo_seq_fops,
1797         .seq_ops        = {
1798                 .show           = tcp6_seq_show,
1799         },
1800 };
1801
1802 int __net_init tcp6_proc_init(struct net *net)
1803 {
1804         return tcp_proc_register(net, &tcp6_seq_afinfo);
1805 }
1806
1807 void tcp6_proc_exit(struct net *net)
1808 {
1809         tcp_proc_unregister(net, &tcp6_seq_afinfo);
1810 }
1811 #endif
1812
1813 static void tcp_v6_clear_sk(struct sock *sk, int size)
1814 {
1815         struct inet_sock *inet = inet_sk(sk);
1816
1817         /* we do not want to clear pinet6 field, because of RCU lookups */
1818         sk_prot_clear_nulls(sk, offsetof(struct inet_sock, pinet6));
1819
1820         size -= offsetof(struct inet_sock, pinet6) + sizeof(inet->pinet6);
1821         memset(&inet->pinet6 + 1, 0, size);
1822 }
1823
1824 struct proto tcpv6_prot = {
1825         .name                   = "TCPv6",
1826         .owner                  = THIS_MODULE,
1827         .close                  = tcp_close,
1828         .connect                = tcp_v6_connect,
1829         .disconnect             = tcp_disconnect,
1830         .accept                 = inet_csk_accept,
1831         .ioctl                  = tcp_ioctl,
1832         .init                   = tcp_v6_init_sock,
1833         .destroy                = tcp_v6_destroy_sock,
1834         .shutdown               = tcp_shutdown,
1835         .setsockopt             = tcp_setsockopt,
1836         .getsockopt             = tcp_getsockopt,
1837         .recvmsg                = tcp_recvmsg,
1838         .sendmsg                = tcp_sendmsg,
1839         .sendpage               = tcp_sendpage,
1840         .backlog_rcv            = tcp_v6_do_rcv,
1841         .release_cb             = tcp_release_cb,
1842         .hash                   = inet_hash,
1843         .unhash                 = inet_unhash,
1844         .get_port               = inet_csk_get_port,
1845         .enter_memory_pressure  = tcp_enter_memory_pressure,
1846         .stream_memory_free     = tcp_stream_memory_free,
1847         .sockets_allocated      = &tcp_sockets_allocated,
1848         .memory_allocated       = &tcp_memory_allocated,
1849         .memory_pressure        = &tcp_memory_pressure,
1850         .orphan_count           = &tcp_orphan_count,
1851         .sysctl_mem             = sysctl_tcp_mem,
1852         .sysctl_wmem            = sysctl_tcp_wmem,
1853         .sysctl_rmem            = sysctl_tcp_rmem,
1854         .max_header             = MAX_TCP_HEADER,
1855         .obj_size               = sizeof(struct tcp6_sock),
1856         .slab_flags             = SLAB_DESTROY_BY_RCU,
1857         .twsk_prot              = &tcp6_timewait_sock_ops,
1858         .rsk_prot               = &tcp6_request_sock_ops,
1859         .h.hashinfo             = &tcp_hashinfo,
1860         .no_autobind            = true,
1861 #ifdef CONFIG_COMPAT
1862         .compat_setsockopt      = compat_tcp_setsockopt,
1863         .compat_getsockopt      = compat_tcp_getsockopt,
1864 #endif
1865 #ifdef CONFIG_MEMCG_KMEM
1866         .proto_cgroup           = tcp_proto_cgroup,
1867 #endif
1868         .clear_sk               = tcp_v6_clear_sk,
1869 };
1870
1871 static const struct inet6_protocol tcpv6_protocol = {
1872         .early_demux    =       tcp_v6_early_demux,
1873         .handler        =       tcp_v6_rcv,
1874         .err_handler    =       tcp_v6_err,
1875         .flags          =       INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
1876 };
1877
1878 static struct inet_protosw tcpv6_protosw = {
1879         .type           =       SOCK_STREAM,
1880         .protocol       =       IPPROTO_TCP,
1881         .prot           =       &tcpv6_prot,
1882         .ops            =       &inet6_stream_ops,
1883         .flags          =       INET_PROTOSW_PERMANENT |
1884                                 INET_PROTOSW_ICSK,
1885 };
1886
1887 static int __net_init tcpv6_net_init(struct net *net)
1888 {
1889         return inet_ctl_sock_create(&net->ipv6.tcp_sk, PF_INET6,
1890                                     SOCK_RAW, IPPROTO_TCP, net);
1891 }
1892
1893 static void __net_exit tcpv6_net_exit(struct net *net)
1894 {
1895         inet_ctl_sock_destroy(net->ipv6.tcp_sk);
1896 }
1897
1898 static void __net_exit tcpv6_net_exit_batch(struct list_head *net_exit_list)
1899 {
1900         inet_twsk_purge(&tcp_hashinfo, &tcp_death_row, AF_INET6);
1901 }
1902
1903 static struct pernet_operations tcpv6_net_ops = {
1904         .init       = tcpv6_net_init,
1905         .exit       = tcpv6_net_exit,
1906         .exit_batch = tcpv6_net_exit_batch,
1907 };
1908
1909 int __init tcpv6_init(void)
1910 {
1911         int ret;
1912
1913         ret = inet6_add_protocol(&tcpv6_protocol, IPPROTO_TCP);
1914         if (ret)
1915                 goto out;
1916
1917         /* register inet6 protocol */
1918         ret = inet6_register_protosw(&tcpv6_protosw);
1919         if (ret)
1920                 goto out_tcpv6_protocol;
1921
1922         ret = register_pernet_subsys(&tcpv6_net_ops);
1923         if (ret)
1924                 goto out_tcpv6_protosw;
1925 out:
1926         return ret;
1927
1928 out_tcpv6_protosw:
1929         inet6_unregister_protosw(&tcpv6_protosw);
1930 out_tcpv6_protocol:
1931         inet6_del_protocol(&tcpv6_protocol, IPPROTO_TCP);
1932         goto out;
1933 }
1934
1935 void tcpv6_exit(void)
1936 {
1937         unregister_pernet_subsys(&tcpv6_net_ops);
1938         inet6_unregister_protosw(&tcpv6_protosw);
1939         inet6_del_protocol(&tcpv6_protocol, IPPROTO_TCP);
1940 }