net/ipv6/tcp_ipv6.c

   1 /*
   2  *      TCP over IPv6
   3  *      Linux INET6 implementation
   4  *
   5  *      Authors:
   6  *      Pedro Roque             <roque@di.fc.ul.pt>
   7  *
   8  *      Based on:
   9  *      linux/net/ipv4/tcp.c
  10  *      linux/net/ipv4/tcp_input.c
  11  *      linux/net/ipv4/tcp_output.c
  12  *
  13  *      Fixes:
  14  *      Hideaki YOSHIFUJI       :       sin6_scope_id support
  15  *      YOSHIFUJI Hideaki @USAGI and:   Support IPV6_V6ONLY socket option, which
  16  *      Alexey Kuznetsov                allow both IPv4 and IPv6 sockets to bind
  17  *                                      a single port at the same time.
  18  *      YOSHIFUJI Hideaki @USAGI:       convert /proc/net/tcp6 to seq_file.
  19  *
  20  *      This program is free software; you can redistribute it and/or
  21  *      modify it under the terms of the GNU General Public License
  22  *      as published by the Free Software Foundation; either version
  23  *      2 of the License, or (at your option) any later version.
  24  */
  25
  26 #include <linux/bottom_half.h>
  27 #include <linux/module.h>
  28 #include <linux/errno.h>
  29 #include <linux/types.h>
  30 #include <linux/socket.h>
  31 #include <linux/sockios.h>
  32 #include <linux/net.h>
  33 #include <linux/jiffies.h>
  34 #include <linux/in.h>
  35 #include <linux/in6.h>
  36 #include <linux/netdevice.h>
  37 #include <linux/init.h>
  38 #include <linux/jhash.h>
  39 #include <linux/ipsec.h>
  40 #include <linux/times.h>
  41 #include <linux/slab.h>
  42 #include <linux/uaccess.h>
  43 #include <linux/ipv6.h>
  44 #include <linux/icmpv6.h>
  45 #include <linux/random.h>
  46
  47 #include <net/tcp.h>
  48 #include <net/ndisc.h>
  49 #include <net/inet6_hashtables.h>
  50 #include <net/inet6_connection_sock.h>
  51 #include <net/ipv6.h>
  52 #include <net/transp_v6.h>
  53 #include <net/addrconf.h>
  54 #include <net/ip6_route.h>
  55 #include <net/ip6_checksum.h>
  56 #include <net/inet_ecn.h>
  57 #include <net/protocol.h>
  58 #include <net/xfrm.h>
  59 #include <net/snmp.h>
  60 #include <net/dsfield.h>
  61 #include <net/timewait_sock.h>
  62 #include <net/inet_common.h>
  63 #include <net/secure_seq.h>
  64 #include <net/busy_poll.h>
  65
  66 #include <linux/proc_fs.h>
  67 #include <linux/seq_file.h>
  68
  69 #include <crypto/hash.h>
  70 #include <linux/scatterlist.h>
  71
  72 static void     tcp_v6_send_reset(const struct sock *sk, struct sk_buff *skb);
  73 static void     tcp_v6_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb,
  74                                       struct request_sock *req);
  75
  76 static int      tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb);
  77
  78 static const struct inet_connection_sock_af_ops ipv6_mapped;
  79 static const struct inet_connection_sock_af_ops ipv6_specific;
  80 #ifdef CONFIG_TCP_MD5SIG
  81 static const struct tcp_sock_af_ops tcp_sock_ipv6_specific;
  82 static const struct tcp_sock_af_ops tcp_sock_ipv6_mapped_specific;
  83 #else
  84 static struct tcp_md5sig_key *tcp_v6_md5_do_lookup(const struct sock *sk,
  85                                                    const struct in6_addr *addr)
  86 {
  87         return NULL;
  88 }
  89 #endif
  90
  91 static void inet6_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb)
  92 {
  93         struct dst_entry *dst = skb_dst(skb);
  94
  95         if (dst && dst_hold_safe(dst)) {
  96                 const struct rt6_info *rt = (const struct rt6_info *)dst;
  97
  98                 sk->sk_rx_dst = dst;
  99                 inet_sk(sk)->rx_dst_ifindex = skb->skb_iif;
 100                 inet6_sk(sk)->rx_dst_cookie = rt6_get_cookie(rt);
 101         }
 102 }
 103
 104 static __u32 tcp_v6_init_sequence(const struct sk_buff *skb)
 105 {
 106         return secure_tcpv6_sequence_number(ipv6_hdr(skb)->daddr.s6_addr32,
 107                                             ipv6_hdr(skb)->saddr.s6_addr32,
 108                                             tcp_hdr(skb)->dest,
 109                                             tcp_hdr(skb)->source);
 110 }
 111
 112 static int tcp_v6_connect(struct sock *sk, struct sockaddr *uaddr,
 113                           int addr_len)
 114 {
 115         struct sockaddr_in6 *usin = (struct sockaddr_in6 *) uaddr;
 116         struct inet_sock *inet = inet_sk(sk);
 117         struct inet_connection_sock *icsk = inet_csk(sk);
 118         struct ipv6_pinfo *np = inet6_sk(sk);
 119         struct tcp_sock *tp = tcp_sk(sk);
 120         struct in6_addr *saddr = NULL, *final_p, final;
 121         struct ipv6_txoptions *opt;
 122         struct flowi6 fl6;
 123         struct dst_entry *dst;
 124         int addr_type;
 125         int err;
 126
 127         if (addr_len < SIN6_LEN_RFC2133)
 128                 return -EINVAL;
 129
 130         if (usin->sin6_family != AF_INET6)
 131                 return -EAFNOSUPPORT;
 132
 133         memset(&fl6, 0, sizeof(fl6));
 134
 135         if (np->sndflow) {
 136                 fl6.flowlabel = usin->sin6_flowinfo&IPV6_FLOWINFO_MASK;
 137                 IP6_ECN_flow_init(fl6.flowlabel);
 138                 if (fl6.flowlabel&IPV6_FLOWLABEL_MASK) {
 139                         struct ip6_flowlabel *flowlabel;
 140                         flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
 141                         if (!flowlabel)
 142                                 return -EINVAL;
 143                         fl6_sock_release(flowlabel);
 144                 }
 145         }
 146
 147         /*
 148          *      connect() to INADDR_ANY means loopback (BSD'ism).
 149          */
 150
 151         if (ipv6_addr_any(&usin->sin6_addr))
 152                 usin->sin6_addr.s6_addr[15] = 0x1;
 153
 154         addr_type = ipv6_addr_type(&usin->sin6_addr);
 155
 156         if (addr_type & IPV6_ADDR_MULTICAST)
 157                 return -ENETUNREACH;
 158
 159         if (addr_type&IPV6_ADDR_LINKLOCAL) {
 160                 if (addr_len >= sizeof(struct sockaddr_in6) &&
 161                     usin->sin6_scope_id) {
 162                         /* If interface is set while binding, indices
 163                          * must coincide.
 164                          */
 165                         if (sk->sk_bound_dev_if &&
 166                             sk->sk_bound_dev_if != usin->sin6_scope_id)
 167                                 return -EINVAL;
 168
 169                         sk->sk_bound_dev_if = usin->sin6_scope_id;
 170                 }
 171
 172                 /* Connect to link-local address requires an interface */
 173                 if (!sk->sk_bound_dev_if)
 174                         return -EINVAL;
 175         }
 176
 177         if (tp->rx_opt.ts_recent_stamp &&
 178             !ipv6_addr_equal(&sk->sk_v6_daddr, &usin->sin6_addr)) {
 179                 tp->rx_opt.ts_recent = 0;
 180                 tp->rx_opt.ts_recent_stamp = 0;
 181                 tp->write_seq = 0;
 182         }
 183
 184         sk->sk_v6_daddr = usin->sin6_addr;
 185         np->flow_label = fl6.flowlabel;
 186
 187         /*
 188          *      TCP over IPv4
 189          */
 190
 191         if (addr_type == IPV6_ADDR_MAPPED) {
 192                 u32 exthdrlen = icsk->icsk_ext_hdr_len;
 193                 struct sockaddr_in sin;
 194
 195                 SOCK_DEBUG(sk, "connect: ipv4 mapped\n");
 196
 197                 if (__ipv6_only_sock(sk))
 198                         return -ENETUNREACH;
 199
 200                 sin.sin_family = AF_INET;
 201                 sin.sin_port = usin->sin6_port;
 202                 sin.sin_addr.s_addr = usin->sin6_addr.s6_addr32[3];
 203
 204                 icsk->icsk_af_ops = &ipv6_mapped;
 205                 sk->sk_backlog_rcv = tcp_v4_do_rcv;
 206 #ifdef CONFIG_TCP_MD5SIG
 207                 tp->af_specific = &tcp_sock_ipv6_mapped_specific;
 208 #endif
 209
 210                 err = tcp_v4_connect(sk, (struct sockaddr *)&sin, sizeof(sin));
 211
 212                 if (err) {
 213                         icsk->icsk_ext_hdr_len = exthdrlen;
 214                         icsk->icsk_af_ops = &ipv6_specific;
 215                         sk->sk_backlog_rcv = tcp_v6_do_rcv;
 216 #ifdef CONFIG_TCP_MD5SIG
 217                         tp->af_specific = &tcp_sock_ipv6_specific;
 218 #endif
 219                         goto failure;
 220                 }
 221                 np->saddr = sk->sk_v6_rcv_saddr;
 222
 223                 return err;
 224         }
 225
 226         if (!ipv6_addr_any(&sk->sk_v6_rcv_saddr))
 227                 saddr = &sk->sk_v6_rcv_saddr;
 228
 229         fl6.flowi6_proto = IPPROTO_TCP;
 230         fl6.daddr = sk->sk_v6_daddr;
 231         fl6.saddr = saddr ? *saddr : np->saddr;
 232         fl6.flowi6_oif = sk->sk_bound_dev_if;
 233         fl6.flowi6_mark = sk->sk_mark;
 234         fl6.fl6_dport = usin->sin6_port;
 235         fl6.fl6_sport = inet->inet_sport;
 236
 237         opt = rcu_dereference_protected(np->opt, lockdep_sock_is_held(sk));
 238         final_p = fl6_update_dst(&fl6, opt, &final);
 239
 240         security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));
 241
 242         dst = ip6_dst_lookup_flow(sk, &fl6, final_p);
 243         if (IS_ERR(dst)) {
 244                 err = PTR_ERR(dst);
 245                 goto failure;
 246         }
 247
 248         if (!saddr) {
 249                 saddr = &fl6.saddr;
 250                 sk->sk_v6_rcv_saddr = *saddr;
 251         }
 252
 253         /* set the source address */
 254         np->saddr = *saddr;
 255         inet->inet_rcv_saddr = LOOPBACK4_IPV6;
 256
 257         sk->sk_gso_type = SKB_GSO_TCPV6;
 258         ip6_dst_store(sk, dst, NULL, NULL);
 259
 260         if (tcp_death_row.sysctl_tw_recycle &&
 261             !tp->rx_opt.ts_recent_stamp &&
 262             ipv6_addr_equal(&fl6.daddr, &sk->sk_v6_daddr))
 263                 tcp_fetch_timewait_stamp(sk, dst);
 264
 265         icsk->icsk_ext_hdr_len = 0;
 266         if (opt)
 267                 icsk->icsk_ext_hdr_len = opt->opt_flen +
 268                                          opt->opt_nflen;
 269
 270         tp->rx_opt.mss_clamp = IPV6_MIN_MTU - sizeof(struct tcphdr) - sizeof(struct ipv6hdr);
 271
 272         inet->inet_dport = usin->sin6_port;
 273
 274         tcp_set_state(sk, TCP_SYN_SENT);
 275         err = inet6_hash_connect(&tcp_death_row, sk);
 276         if (err)
 277                 goto late_failure;
 278
 279         sk_set_txhash(sk);
 280
 281         if (!tp->write_seq && likely(!tp->repair))
 282                 tp->write_seq = secure_tcpv6_sequence_number(np->saddr.s6_addr32,
 283                                                              sk->sk_v6_daddr.s6_addr32,
 284                                                              inet->inet_sport,
 285                                                              inet->inet_dport);
 286
 287         err = tcp_connect(sk);
 288         if (err)
 289                 goto late_failure;
 290
 291         return 0;
 292
 293 late_failure:
 294         tcp_set_state(sk, TCP_CLOSE);
 295         __sk_dst_reset(sk);
 296 failure:
 297         inet->inet_dport = 0;
 298         sk->sk_route_caps = 0;
 299         return err;
 300 }
 301
 302 static void tcp_v6_mtu_reduced(struct sock *sk)
 303 {
 304         struct dst_entry *dst;
 305
 306         if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE))
 307                 return;
 308
 309         dst = inet6_csk_update_pmtu(sk, tcp_sk(sk)->mtu_info);
 310         if (!dst)
 311                 return;
 312
 313         if (inet_csk(sk)->icsk_pmtu_cookie > dst_mtu(dst)) {
 314                 tcp_sync_mss(sk, dst_mtu(dst));
 315                 tcp_simple_retransmit(sk);
 316         }
 317 }
 318
 319 static void tcp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 320                 u8 type, u8 code, int offset, __be32 info)
 321 {
 322         const struct ipv6hdr *hdr = (const struct ipv6hdr *)skb->data;
 323         const struct tcphdr *th = (struct tcphdr *)(skb->data+offset);
 324         struct net *net = dev_net(skb->dev);
 325         struct request_sock *fastopen;
 326         struct ipv6_pinfo *np;
 327         struct tcp_sock *tp;
 328         __u32 seq, snd_una;
 329         struct sock *sk;
 330         bool fatal;
 331         int err;
 332
 333         sk = __inet6_lookup_established(net, &tcp_hashinfo,
 334                                         &hdr->daddr, th->dest,
 335                                         &hdr->saddr, ntohs(th->source),
 336                                         skb->dev->ifindex);
 337
 338         if (!sk) {
 339                 __ICMP6_INC_STATS(net, __in6_dev_get(skb->dev),
 340                                   ICMP6_MIB_INERRORS);
 341                 return;
 342         }
 343
 344         if (sk->sk_state == TCP_TIME_WAIT) {
 345                 inet_twsk_put(inet_twsk(sk));
 346                 return;
 347         }
 348         seq = ntohl(th->seq);
 349         fatal = icmpv6_err_convert(type, code, &err);
 350         if (sk->sk_state == TCP_NEW_SYN_RECV)
 351                 return tcp_req_err(sk, seq, fatal);
 352
 353         bh_lock_sock(sk);
 354         if (sock_owned_by_user(sk) && type != ICMPV6_PKT_TOOBIG)
 355                 __NET_INC_STATS(net, LINUX_MIB_LOCKDROPPEDICMPS);
 356
 357         if (sk->sk_state == TCP_CLOSE)
 358                 goto out;
 359
 360         if (ipv6_hdr(skb)->hop_limit < inet6_sk(sk)->min_hopcount) {
 361                 __NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP);
 362                 goto out;
 363         }
 364
 365         tp = tcp_sk(sk);
 366         /* XXX (TFO) - tp->snd_una should be ISN (tcp_create_openreq_child() */
 367         fastopen = tp->fastopen_rsk;
 368         snd_una = fastopen ? tcp_rsk(fastopen)->snt_isn : tp->snd_una;
 369         if (sk->sk_state != TCP_LISTEN &&
 370             !between(seq, snd_una, tp->snd_nxt)) {
 371                 __NET_INC_STATS(net, LINUX_MIB_OUTOFWINDOWICMPS);
 372                 goto out;
 373         }
 374
 375         np = inet6_sk(sk);
 376
 377         if (type == NDISC_REDIRECT) {
 378                 struct dst_entry *dst = __sk_dst_check(sk, np->dst_cookie);
 379
 380                 if (dst)
 381                         dst->ops->redirect(dst, sk, skb);
 382                 goto out;
 383         }
 384
 385         if (type == ICMPV6_PKT_TOOBIG) {
 386                 /* We are not interested in TCP_LISTEN and open_requests
 387                  * (SYN-ACKs send out by Linux are always <576bytes so
 388                  * they should go through unfragmented).
 389                  */
 390                 if (sk->sk_state == TCP_LISTEN)
 391                         goto out;
 392
 393                 if (!ip6_sk_accept_pmtu(sk))
 394                         goto out;
 395
 396                 tp->mtu_info = ntohl(info);
 397                 if (!sock_owned_by_user(sk))
 398                         tcp_v6_mtu_reduced(sk);
 399                 else if (!test_and_set_bit(TCP_MTU_REDUCED_DEFERRED,
 400                                            &tp->tsq_flags))
 401                         sock_hold(sk);
 402                 goto out;
 403         }
 404
 405
 406         /* Might be for an request_sock */
 407         switch (sk->sk_state) {
 408         case TCP_SYN_SENT:
 409         case TCP_SYN_RECV:
 410                 /* Only in fast or simultaneous open. If a fast open socket is
 411                  * is already accepted it is treated as a connected one below.
 412                  */
 413                 if (fastopen && !fastopen->sk)
 414                         break;
 415
 416                 if (!sock_owned_by_user(sk)) {
 417                         sk->sk_err = err;
 418                         sk->sk_error_report(sk);                /* Wake people up to see the error (see connect in sock.c) */
 419
 420                         tcp_done(sk);
 421                 } else
 422                         sk->sk_err_soft = err;
 423                 goto out;
 424         }
 425
 426         if (!sock_owned_by_user(sk) && np->recverr) {
 427                 sk->sk_err = err;
 428                 sk->sk_error_report(sk);
 429         } else
 430                 sk->sk_err_soft = err;
 431
 432 out:
 433         bh_unlock_sock(sk);
 434         sock_put(sk);
 435 }
 436
 437
 438 static int tcp_v6_send_synack(const struct sock *sk, struct dst_entry *dst,
 439                               struct flowi *fl,
 440                               struct request_sock *req,
 441                               struct tcp_fastopen_cookie *foc,
 442                               enum tcp_synack_type synack_type)
 443 {
 444         struct inet_request_sock *ireq = inet_rsk(req);
 445         struct ipv6_pinfo *np = inet6_sk(sk);
 446         struct ipv6_txoptions *opt;
 447         struct flowi6 *fl6 = &fl->u.ip6;
 448         struct sk_buff *skb;
 449         int err = -ENOMEM;
 450
 451         /* First, grab a route. */
 452         if (!dst && (dst = inet6_csk_route_req(sk, fl6, req,
 453                                                IPPROTO_TCP)) == NULL)
 454                 goto done;
 455
 456         skb = tcp_make_synack(sk, dst, req, foc, synack_type);
 457
 458         if (skb) {
 459                 __tcp_v6_send_check(skb, &ireq->ir_v6_loc_addr,
 460                                     &ireq->ir_v6_rmt_addr);
 461
 462                 fl6->daddr = ireq->ir_v6_rmt_addr;
 463                 if (np->repflow && ireq->pktopts)
 464                         fl6->flowlabel = ip6_flowlabel(ipv6_hdr(ireq->pktopts));
 465
 466                 rcu_read_lock();
 467                 opt = ireq->ipv6_opt;
 468                 if (!opt)
 469                         opt = rcu_dereference(np->opt);
 470                 err = ip6_xmit(sk, skb, fl6, opt, np->tclass);
 471                 rcu_read_unlock();
 472                 err = net_xmit_eval(err);
 473         }
 474
 475 done:
 476         return err;
 477 }
 478
 479
 480 static void tcp_v6_reqsk_destructor(struct request_sock *req)
 481 {
 482         kfree(inet_rsk(req)->ipv6_opt);
 483         kfree_skb(inet_rsk(req)->pktopts);
 484 }
 485
 486 #ifdef CONFIG_TCP_MD5SIG
 487 static struct tcp_md5sig_key *tcp_v6_md5_do_lookup(const struct sock *sk,
 488                                                    const struct in6_addr *addr)
 489 {
 490         return tcp_md5_do_lookup(sk, (union tcp_md5_addr *)addr, AF_INET6);
 491 }
 492
 493 static struct tcp_md5sig_key *tcp_v6_md5_lookup(const struct sock *sk,
 494                                                 const struct sock *addr_sk)
 495 {
 496         return tcp_v6_md5_do_lookup(sk, &addr_sk->sk_v6_daddr);
 497 }
 498
 499 static int tcp_v6_parse_md5_keys(struct sock *sk, char __user *optval,
 500                                  int optlen)
 501 {
 502         struct tcp_md5sig cmd;
 503         struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)&cmd.tcpm_addr;
 504
 505         if (optlen < sizeof(cmd))
 506                 return -EINVAL;
 507
 508         if (copy_from_user(&cmd, optval, sizeof(cmd)))
 509                 return -EFAULT;
 510
 511         if (sin6->sin6_family != AF_INET6)
 512                 return -EINVAL;
 513
 514         if (!cmd.tcpm_keylen) {
 515                 if (ipv6_addr_v4mapped(&sin6->sin6_addr))
 516                         return tcp_md5_do_del(sk, (union tcp_md5_addr *)&sin6->sin6_addr.s6_addr32[3],
 517                                               AF_INET);
 518                 return tcp_md5_do_del(sk, (union tcp_md5_addr *)&sin6->sin6_addr,
 519                                       AF_INET6);
 520         }
 521
 522         if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN)
 523                 return -EINVAL;
 524
 525         if (ipv6_addr_v4mapped(&sin6->sin6_addr))
 526                 return tcp_md5_do_add(sk, (union tcp_md5_addr *)&sin6->sin6_addr.s6_addr32[3],
 527                                       AF_INET, cmd.tcpm_key, cmd.tcpm_keylen, GFP_KERNEL);
 528
 529         return tcp_md5_do_add(sk, (union tcp_md5_addr *)&sin6->sin6_addr,
 530                               AF_INET6, cmd.tcpm_key, cmd.tcpm_keylen, GFP_KERNEL);
 531 }
 532
 533 static int tcp_v6_md5_hash_headers(struct tcp_md5sig_pool *hp,
 534                                    const struct in6_addr *daddr,
 535                                    const struct in6_addr *saddr,
 536                                    const struct tcphdr *th, int nbytes)
 537 {
 538         struct tcp6_pseudohdr *bp;
 539         struct scatterlist sg;
 540         struct tcphdr *_th;
 541
 542         bp = hp->scratch;
 543         /* 1. TCP pseudo-header (RFC2460) */
 544         bp->saddr = *saddr;
 545         bp->daddr = *daddr;
 546         bp->protocol = cpu_to_be32(IPPROTO_TCP);
 547         bp->len = cpu_to_be32(nbytes);
 548
 549         _th = (struct tcphdr *)(bp + 1);
 550         memcpy(_th, th, sizeof(*th));
 551         _th->check = 0;
 552
 553         sg_init_one(&sg, bp, sizeof(*bp) + sizeof(*th));
 554         ahash_request_set_crypt(hp->md5_req, &sg, NULL,
 555                                 sizeof(*bp) + sizeof(*th));
 556         return crypto_ahash_update(hp->md5_req);
 557 }
 558
 559 static int tcp_v6_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key,
 560                                const struct in6_addr *daddr, struct in6_addr *saddr,
 561                                const struct tcphdr *th)
 562 {
 563         struct tcp_md5sig_pool *hp;
 564         struct ahash_request *req;
 565
 566         hp = tcp_get_md5sig_pool();
 567         if (!hp)
 568                 goto clear_hash_noput;
 569         req = hp->md5_req;
 570
 571         if (crypto_ahash_init(req))
 572                 goto clear_hash;
 573         if (tcp_v6_md5_hash_headers(hp, daddr, saddr, th, th->doff << 2))
 574                 goto clear_hash;
 575         if (tcp_md5_hash_key(hp, key))
 576                 goto clear_hash;
 577         ahash_request_set_crypt(req, NULL, md5_hash, 0);
 578         if (crypto_ahash_final(req))
 579                 goto clear_hash;
 580
 581         tcp_put_md5sig_pool();
 582         return 0;
 583
 584 clear_hash:
 585         tcp_put_md5sig_pool();
 586 clear_hash_noput:
 587         memset(md5_hash, 0, 16);
 588         return 1;
 589 }
 590
 591 static int tcp_v6_md5_hash_skb(char *md5_hash,
 592                                const struct tcp_md5sig_key *key,
 593                                const struct sock *sk,
 594                                const struct sk_buff *skb)
 595 {
 596         const struct in6_addr *saddr, *daddr;
 597         struct tcp_md5sig_pool *hp;
 598         struct ahash_request *req;
 599         const struct tcphdr *th = tcp_hdr(skb);
 600
 601         if (sk) { /* valid for establish/request sockets */
 602                 saddr = &sk->sk_v6_rcv_saddr;
 603                 daddr = &sk->sk_v6_daddr;
 604         } else {
 605                 const struct ipv6hdr *ip6h = ipv6_hdr(skb);
 606                 saddr = &ip6h->saddr;
 607                 daddr = &ip6h->daddr;
 608         }
 609
 610         hp = tcp_get_md5sig_pool();
 611         if (!hp)
 612                 goto clear_hash_noput;
 613         req = hp->md5_req;
 614
 615         if (crypto_ahash_init(req))
 616                 goto clear_hash;
 617
 618         if (tcp_v6_md5_hash_headers(hp, daddr, saddr, th, skb->len))
 619                 goto clear_hash;
 620         if (tcp_md5_hash_skb_data(hp, skb, th->doff << 2))
 621                 goto clear_hash;
 622         if (tcp_md5_hash_key(hp, key))
 623                 goto clear_hash;
 624         ahash_request_set_crypt(req, NULL, md5_hash, 0);
 625         if (crypto_ahash_final(req))
 626                 goto clear_hash;
 627
 628         tcp_put_md5sig_pool();
 629         return 0;
 630
 631 clear_hash:
 632         tcp_put_md5sig_pool();
 633 clear_hash_noput:
 634         memset(md5_hash, 0, 16);
 635         return 1;
 636 }
 637
 638 #endif
 639
 640 static bool tcp_v6_inbound_md5_hash(const struct sock *sk,
 641                                     const struct sk_buff *skb)
 642 {
 643 #ifdef CONFIG_TCP_MD5SIG
 644         const __u8 *hash_location = NULL;
 645         struct tcp_md5sig_key *hash_expected;
 646         const struct ipv6hdr *ip6h = ipv6_hdr(skb);
 647         const struct tcphdr *th = tcp_hdr(skb);
 648         int genhash;
 649         u8 newhash[16];
 650
 651         hash_expected = tcp_v6_md5_do_lookup(sk, &ip6h->saddr);
 652         hash_location = tcp_parse_md5sig_option(th);
 653
 654         /* We've parsed the options - do we have a hash? */
 655         if (!hash_expected && !hash_location)
 656                 return false;
 657
 658         if (hash_expected && !hash_location) {
 659                 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5NOTFOUND);
 660                 return true;
 661         }
 662
 663         if (!hash_expected && hash_location) {
 664                 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5UNEXPECTED);
 665                 return true;
 666         }
 667
 668         /* check the signature */
 669         genhash = tcp_v6_md5_hash_skb(newhash,
 670                                       hash_expected,
 671                                       NULL, skb);
 672
 673         if (genhash || memcmp(hash_location, newhash, 16) != 0) {
 674                 net_info_ratelimited("MD5 Hash %s for [%pI6c]:%u->[%pI6c]:%u\n",
 675                                      genhash ? "failed" : "mismatch",
 676                                      &ip6h->saddr, ntohs(th->source),
 677                                      &ip6h->daddr, ntohs(th->dest));
 678                 return true;
 679         }
 680 #endif
 681         return false;
 682 }
 683
 684 static void tcp_v6_init_req(struct request_sock *req,
 685                             const struct sock *sk_listener,
 686                             struct sk_buff *skb)
 687 {
 688         struct inet_request_sock *ireq = inet_rsk(req);
 689         const struct ipv6_pinfo *np = inet6_sk(sk_listener);
 690
 691         ireq->ir_v6_rmt_addr = ipv6_hdr(skb)->saddr;
 692         ireq->ir_v6_loc_addr = ipv6_hdr(skb)->daddr;
 693
 694         /* So that link locals have meaning */
 695         if (!sk_listener->sk_bound_dev_if &&
 696             ipv6_addr_type(&ireq->ir_v6_rmt_addr) & IPV6_ADDR_LINKLOCAL)
 697                 ireq->ir_iif = tcp_v6_iif(skb);
 698
 699         if (!TCP_SKB_CB(skb)->tcp_tw_isn &&
 700             (ipv6_opt_accepted(sk_listener, skb, &TCP_SKB_CB(skb)->header.h6) ||
 701              np->rxopt.bits.rxinfo ||
 702              np->rxopt.bits.rxoinfo || np->rxopt.bits.rxhlim ||
 703              np->rxopt.bits.rxohlim || np->repflow)) {
 704                 atomic_inc(&skb->users);
 705                 ireq->pktopts = skb;
 706         }
 707 }
 708
 709 static struct dst_entry *tcp_v6_route_req(const struct sock *sk,
 710                                           struct flowi *fl,
 711                                           const struct request_sock *req,
 712                                           bool *strict)
 713 {
 714         if (strict)
 715                 *strict = true;
 716         return inet6_csk_route_req(sk, &fl->u.ip6, req, IPPROTO_TCP);
 717 }
 718
 719 struct request_sock_ops tcp6_request_sock_ops __read_mostly = {
 720         .family         =       AF_INET6,
 721         .obj_size       =       sizeof(struct tcp6_request_sock),
 722         .rtx_syn_ack    =       tcp_rtx_synack,
 723         .send_ack       =       tcp_v6_reqsk_send_ack,
 724         .destructor     =       tcp_v6_reqsk_destructor,
 725         .send_reset     =       tcp_v6_send_reset,
 726         .syn_ack_timeout =      tcp_syn_ack_timeout,
 727 };
 728
 729 static const struct tcp_request_sock_ops tcp_request_sock_ipv6_ops = {
 730         .mss_clamp      =       IPV6_MIN_MTU - sizeof(struct tcphdr) -
 731                                 sizeof(struct ipv6hdr),
 732 #ifdef CONFIG_TCP_MD5SIG
 733         .req_md5_lookup =       tcp_v6_md5_lookup,
 734         .calc_md5_hash  =       tcp_v6_md5_hash_skb,
 735 #endif
 736         .init_req       =       tcp_v6_init_req,
 737 #ifdef CONFIG_SYN_COOKIES
 738         .cookie_init_seq =      cookie_v6_init_sequence,
 739 #endif
 740         .route_req      =       tcp_v6_route_req,
 741         .init_seq       =       tcp_v6_init_sequence,
 742         .send_synack    =       tcp_v6_send_synack,
 743 };
 744
 745 static void tcp_v6_send_response(const struct sock *sk, struct sk_buff *skb, u32 seq,
 746                                  u32 ack, u32 win, u32 tsval, u32 tsecr,
 747                                  int oif, struct tcp_md5sig_key *key, int rst,
 748                                  u8 tclass, __be32 label)
 749 {
 750         const struct tcphdr *th = tcp_hdr(skb);
 751         struct tcphdr *t1;
 752         struct sk_buff *buff;
 753         struct flowi6 fl6;
 754         struct net *net = sk ? sock_net(sk) : dev_net(skb_dst(skb)->dev);
 755         struct sock *ctl_sk = net->ipv6.tcp_sk;
 756         unsigned int tot_len = sizeof(struct tcphdr);
 757         struct dst_entry *dst;
 758         __be32 *topt;
 759
 760         if (tsecr)
 761                 tot_len += TCPOLEN_TSTAMP_ALIGNED;
 762 #ifdef CONFIG_TCP_MD5SIG
 763         if (key)
 764                 tot_len += TCPOLEN_MD5SIG_ALIGNED;
 765 #endif
 766
 767         buff = alloc_skb(MAX_HEADER + sizeof(struct ipv6hdr) + tot_len,
 768                          GFP_ATOMIC);
 769         if (!buff)
 770                 return;
 771
 772         skb_reserve(buff, MAX_HEADER + sizeof(struct ipv6hdr) + tot_len);
 773
 774         t1 = (struct tcphdr *) skb_push(buff, tot_len);
 775         skb_reset_transport_header(buff);
 776
 777         /* Swap the send and the receive. */
 778         memset(t1, 0, sizeof(*t1));
 779         t1->dest = th->source;
 780         t1->source = th->dest;
 781         t1->doff = tot_len / 4;
 782         t1->seq = htonl(seq);
 783         t1->ack_seq = htonl(ack);
 784         t1->ack = !rst || !th->ack;
 785         t1->rst = rst;
 786         t1->window = htons(win);
 787
 788         topt = (__be32 *)(t1 + 1);
 789
 790         if (tsecr) {
 791                 *topt++ = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
 792                                 (TCPOPT_TIMESTAMP << 8) | TCPOLEN_TIMESTAMP);
 793                 *topt++ = htonl(tsval);
 794                 *topt++ = htonl(tsecr);
 795         }
 796
 797 #ifdef CONFIG_TCP_MD5SIG
 798         if (key) {
 799                 *topt++ = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
 800                                 (TCPOPT_MD5SIG << 8) | TCPOLEN_MD5SIG);
 801                 tcp_v6_md5_hash_hdr((__u8 *)topt, key,
 802                                     &ipv6_hdr(skb)->saddr,
 803                                     &ipv6_hdr(skb)->daddr, t1);
 804         }
 805 #endif
 806
 807         memset(&fl6, 0, sizeof(fl6));
 808         fl6.daddr = ipv6_hdr(skb)->saddr;
 809         fl6.saddr = ipv6_hdr(skb)->daddr;
 810         fl6.flowlabel = label;
 811
 812         buff->ip_summed = CHECKSUM_PARTIAL;
 813         buff->csum = 0;
 814
 815         __tcp_v6_send_check(buff, &fl6.saddr, &fl6.daddr);
 816
 817         fl6.flowi6_proto = IPPROTO_TCP;
 818         if (rt6_need_strict(&fl6.daddr) && !oif)
 819                 fl6.flowi6_oif = tcp_v6_iif(skb);
 820         else {
 821                 if (!oif && netif_index_is_l3_master(net, skb->skb_iif))
 822                         oif = skb->skb_iif;
 823
 824                 fl6.flowi6_oif = oif;
 825         }
 826
 827         fl6.flowi6_mark = IP6_REPLY_MARK(net, skb->mark);
 828         fl6.fl6_dport = t1->dest;
 829         fl6.fl6_sport = t1->source;
 830         security_skb_classify_flow(skb, flowi6_to_flowi(&fl6));
 831
 832         /* Pass a socket to ip6_dst_lookup either it is for RST
 833          * Underlying function will use this to retrieve the network
 834          * namespace
 835          */
 836         dst = ip6_dst_lookup_flow(ctl_sk, &fl6, NULL);
 837         if (!IS_ERR(dst)) {
 838                 skb_dst_set(buff, dst);
 839                 ip6_xmit(ctl_sk, buff, &fl6, NULL, tclass);
 840                 TCP_INC_STATS(net, TCP_MIB_OUTSEGS);
 841                 if (rst)
 842                         TCP_INC_STATS(net, TCP_MIB_OUTRSTS);
 843                 return;
 844         }
 845
 846         kfree_skb(buff);
 847 }
 848
 849 static void tcp_v6_send_reset(const struct sock *sk, struct sk_buff *skb)
 850 {
 851         const struct tcphdr *th = tcp_hdr(skb);
 852         u32 seq = 0, ack_seq = 0;
 853         struct tcp_md5sig_key *key = NULL;
 854 #ifdef CONFIG_TCP_MD5SIG
 855         const __u8 *hash_location = NULL;
 856         struct ipv6hdr *ipv6h = ipv6_hdr(skb);
 857         unsigned char newhash[16];
 858         int genhash;
 859         struct sock *sk1 = NULL;
 860 #endif
 861         int oif;
 862
 863         if (th->rst)
 864                 return;
 865
 866         /* If sk not NULL, it means we did a successful lookup and incoming
 867          * route had to be correct. prequeue might have dropped our dst.
 868          */
 869         if (!sk && !ipv6_unicast_destination(skb))
 870                 return;
 871
 872 #ifdef CONFIG_TCP_MD5SIG
 873         rcu_read_lock();
 874         hash_location = tcp_parse_md5sig_option(th);
 875         if (sk && sk_fullsock(sk)) {
 876                 key = tcp_v6_md5_do_lookup(sk, &ipv6h->saddr);
 877         } else if (hash_location) {
 878                 /*
 879                  * active side is lost. Try to find listening socket through
 880                  * source port, and then find md5 key through listening socket.
 881                  * we are not loose security here:
 882                  * Incoming packet is checked with md5 hash with finding key,
 883                  * no RST generated if md5 hash doesn't match.
 884                  */
 885                 sk1 = inet6_lookup_listener(dev_net(skb_dst(skb)->dev),
 886                                            &tcp_hashinfo, NULL, 0,
 887                                            &ipv6h->saddr,
 888                                            th->source, &ipv6h->daddr,
 889                                            ntohs(th->source), tcp_v6_iif(skb));
 890                 if (!sk1)
 891                         goto out;
 892
 893                 key = tcp_v6_md5_do_lookup(sk1, &ipv6h->saddr);
 894                 if (!key)
 895                         goto out;
 896
 897                 genhash = tcp_v6_md5_hash_skb(newhash, key, NULL, skb);
 898                 if (genhash || memcmp(hash_location, newhash, 16) != 0)
 899                         goto out;
 900         }
 901 #endif
 902
 903         if (th->ack)
 904                 seq = ntohl(th->ack_seq);
 905         else
 906                 ack_seq = ntohl(th->seq) + th->syn + th->fin + skb->len -
 907                           (th->doff << 2);
 908
 909         oif = sk ? sk->sk_bound_dev_if : 0;
 910         tcp_v6_send_response(sk, skb, seq, ack_seq, 0, 0, 0, oif, key, 1, 0, 0);
 911
 912 #ifdef CONFIG_TCP_MD5SIG
 913 out:
 914         rcu_read_unlock();
 915 #endif
 916 }
 917
 918 static void tcp_v6_send_ack(const struct sock *sk, struct sk_buff *skb, u32 seq,
 919                             u32 ack, u32 win, u32 tsval, u32 tsecr, int oif,
 920                             struct tcp_md5sig_key *key, u8 tclass,
 921                             __be32 label)
 922 {
 923         tcp_v6_send_response(sk, skb, seq, ack, win, tsval, tsecr, oif, key, 0,
 924                              tclass, label);
 925 }
 926
 927 static void tcp_v6_timewait_ack(struct sock *sk, struct sk_buff *skb)
 928 {
 929         struct inet_timewait_sock *tw = inet_twsk(sk);
 930         struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
 931
 932         tcp_v6_send_ack(sk, skb, tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
 933                         tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
 934                         tcp_time_stamp + tcptw->tw_ts_offset,
 935                         tcptw->tw_ts_recent, tw->tw_bound_dev_if, tcp_twsk_md5_key(tcptw),
 936                         tw->tw_tclass, cpu_to_be32(tw->tw_flowlabel));
 937
 938         inet_twsk_put(tw);
 939 }
 940
 941 static void tcp_v6_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb,
 942                                   struct request_sock *req)
 943 {
 944         /* sk->sk_state == TCP_LISTEN -> for regular TCP_SYN_RECV
 945          * sk->sk_state == TCP_SYN_RECV -> for Fast Open.
 946          */
 947         tcp_v6_send_ack(sk, skb, (sk->sk_state == TCP_LISTEN) ?
 948                         tcp_rsk(req)->snt_isn + 1 : tcp_sk(sk)->snd_nxt,
 949                         tcp_rsk(req)->rcv_nxt, req->rsk_rcv_wnd,
 950                         tcp_time_stamp, req->ts_recent, sk->sk_bound_dev_if,
 951                         tcp_v6_md5_do_lookup(sk, &ipv6_hdr(skb)->daddr),
 952                         0, 0);
 953 }
 954
 955
 956 static struct sock *tcp_v6_cookie_check(struct sock *sk, struct sk_buff *skb)
 957 {
 958 #ifdef CONFIG_SYN_COOKIES
 959         const struct tcphdr *th = tcp_hdr(skb);
 960
 961         if (!th->syn)
 962                 sk = cookie_v6_check(sk, skb);
 963 #endif
 964         return sk;
 965 }
 966
 967 static int tcp_v6_conn_request(struct sock *sk, struct sk_buff *skb)
 968 {
 969         if (skb->protocol == htons(ETH_P_IP))
 970                 return tcp_v4_conn_request(sk, skb);
 971
 972         if (!ipv6_unicast_destination(skb))
 973                 goto drop;
 974
 975         return tcp_conn_request(&tcp6_request_sock_ops,
 976                                 &tcp_request_sock_ipv6_ops, sk, skb);
 977
 978 drop:
 979         tcp_listendrop(sk);
 980         return 0; /* don't send reset */
 981 }
 982
 983 static struct sock *tcp_v6_syn_recv_sock(const struct sock *sk, struct sk_buff *skb,
 984                                          struct request_sock *req,
 985                                          struct dst_entry *dst,
 986                                          struct request_sock *req_unhash,
 987                                          bool *own_req)
 988 {
 989         struct inet_request_sock *ireq;
 990         struct ipv6_pinfo *newnp;
 991         const struct ipv6_pinfo *np = inet6_sk(sk);
 992         struct ipv6_txoptions *opt;
 993         struct tcp6_sock *newtcp6sk;
 994         struct inet_sock *newinet;
 995         struct tcp_sock *newtp;
 996         struct sock *newsk;
 997 #ifdef CONFIG_TCP_MD5SIG
 998         struct tcp_md5sig_key *key;
 999 #endif
1000         struct flowi6 fl6;
1001
1002         if (skb->protocol == htons(ETH_P_IP)) {
1003                 /*
1004                  *      v6 mapped
1005                  */
1006
1007                 newsk = tcp_v4_syn_recv_sock(sk, skb, req, dst,
1008                                              req_unhash, own_req);
1009
1010                 if (!newsk)
1011                         return NULL;
1012
1013                 newtcp6sk = (struct tcp6_sock *)newsk;
1014                 inet_sk(newsk)->pinet6 = &newtcp6sk->inet6;
1015
1016                 newinet = inet_sk(newsk);
1017                 newnp = inet6_sk(newsk);
1018                 newtp = tcp_sk(newsk);
1019
1020                 memcpy(newnp, np, sizeof(struct ipv6_pinfo));
1021
1022                 newnp->saddr = newsk->sk_v6_rcv_saddr;
1023
1024                 inet_csk(newsk)->icsk_af_ops = &ipv6_mapped;
1025                 newsk->sk_backlog_rcv = tcp_v4_do_rcv;
1026 #ifdef CONFIG_TCP_MD5SIG
1027                 newtp->af_specific = &tcp_sock_ipv6_mapped_specific;
1028 #endif
1029
1030                 newnp->ipv6_ac_list = NULL;
1031                 newnp->ipv6_fl_list = NULL;
1032                 newnp->pktoptions  = NULL;
1033                 newnp->opt         = NULL;
1034                 newnp->mcast_oif   = tcp_v6_iif(skb);
1035                 newnp->mcast_hops  = ipv6_hdr(skb)->hop_limit;
1036                 newnp->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(skb));
1037                 if (np->repflow)
1038                         newnp->flow_label = ip6_flowlabel(ipv6_hdr(skb));
1039
1040                 /*
1041                  * No need to charge this sock to the relevant IPv6 refcnt debug socks count
1042                  * here, tcp_create_openreq_child now does this for us, see the comment in
1043                  * that function for the gory details. -acme
1044                  */
1045
1046                 /* It is tricky place. Until this moment IPv4 tcp
1047                    worked with IPv6 icsk.icsk_af_ops.
1048                    Sync it now.
1049                  */
1050                 tcp_sync_mss(newsk, inet_csk(newsk)->icsk_pmtu_cookie);
1051
1052                 return newsk;
1053         }
1054
1055         ireq = inet_rsk(req);
1056
1057         if (sk_acceptq_is_full(sk))
1058                 goto out_overflow;
1059
1060         if (!dst) {
1061                 dst = inet6_csk_route_req(sk, &fl6, req, IPPROTO_TCP);
1062                 if (!dst)
1063                         goto out;
1064         }
1065
1066         newsk = tcp_create_openreq_child(sk, req, skb);
1067         if (!newsk)
1068                 goto out_nonewsk;
1069
1070         /*
1071          * No need to charge this sock to the relevant IPv6 refcnt debug socks
1072          * count here, tcp_create_openreq_child now does this for us, see the
1073          * comment in that function for the gory details. -acme
1074          */
1075
1076         newsk->sk_gso_type = SKB_GSO_TCPV6;
1077         ip6_dst_store(newsk, dst, NULL, NULL);
1078         inet6_sk_rx_dst_set(newsk, skb);
1079
1080         newtcp6sk = (struct tcp6_sock *)newsk;
1081         inet_sk(newsk)->pinet6 = &newtcp6sk->inet6;
1082
1083         newtp = tcp_sk(newsk);
1084         newinet = inet_sk(newsk);
1085         newnp = inet6_sk(newsk);
1086
1087         memcpy(newnp, np, sizeof(struct ipv6_pinfo));
1088
1089         newsk->sk_v6_daddr = ireq->ir_v6_rmt_addr;
1090         newnp->saddr = ireq->ir_v6_loc_addr;
1091         newsk->sk_v6_rcv_saddr = ireq->ir_v6_loc_addr;
1092         newsk->sk_bound_dev_if = ireq->ir_iif;
1093
1094         /* Now IPv6 options...
1095
1096            First: no IPv4 options.
1097          */
1098         newinet->inet_opt = NULL;
1099         newnp->ipv6_ac_list = NULL;
1100         newnp->ipv6_fl_list = NULL;
1101
1102         /* Clone RX bits */
1103         newnp->rxopt.all = np->rxopt.all;
1104
1105         newnp->pktoptions = NULL;
1106         newnp->opt        = NULL;
1107         newnp->mcast_oif  = tcp_v6_iif(skb);
1108         newnp->mcast_hops = ipv6_hdr(skb)->hop_limit;
1109         newnp->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(skb));
1110         if (np->repflow)
1111                 newnp->flow_label = ip6_flowlabel(ipv6_hdr(skb));
1112
1113         /* Clone native IPv6 options from listening socket (if any)
1114
1115            Yes, keeping reference count would be much more clever,
1116            but we make one more one thing there: reattach optmem
1117            to newsk.
1118          */
1119         opt = ireq->ipv6_opt;
1120         if (!opt)
1121                 opt = rcu_dereference(np->opt);
1122         if (opt) {
1123                 opt = ipv6_dup_options(newsk, opt);
1124                 RCU_INIT_POINTER(newnp->opt, opt);
1125         }
1126         inet_csk(newsk)->icsk_ext_hdr_len = 0;
1127         if (opt)
1128                 inet_csk(newsk)->icsk_ext_hdr_len = opt->opt_nflen +
1129                                                     opt->opt_flen;
1130
1131         tcp_ca_openreq_child(newsk, dst);
1132
1133         tcp_sync_mss(newsk, dst_mtu(dst));
1134         newtp->advmss = dst_metric_advmss(dst);
1135         if (tcp_sk(sk)->rx_opt.user_mss &&
1136             tcp_sk(sk)->rx_opt.user_mss < newtp->advmss)
1137                 newtp->advmss = tcp_sk(sk)->rx_opt.user_mss;
1138
1139         tcp_initialize_rcv_mss(newsk);
1140
1141         newinet->inet_daddr = newinet->inet_saddr = LOOPBACK4_IPV6;
1142         newinet->inet_rcv_saddr = LOOPBACK4_IPV6;
1143
1144 #ifdef CONFIG_TCP_MD5SIG
1145         /* Copy over the MD5 key from the original socket */
1146         key = tcp_v6_md5_do_lookup(sk, &newsk->sk_v6_daddr);
1147         if (key) {
1148                 /* We're using one, so create a matching key
1149                  * on the newsk structure. If we fail to get
1150                  * memory, then we end up not copying the key
1151                  * across. Shucks.
1152                  */
1153                 tcp_md5_do_add(newsk, (union tcp_md5_addr *)&newsk->sk_v6_daddr,
1154                                AF_INET6, key->key, key->keylen,
1155                                sk_gfp_mask(sk, GFP_ATOMIC));
1156         }
1157 #endif
1158
1159         if (__inet_inherit_port(sk, newsk) < 0) {
1160                 inet_csk_prepare_forced_close(newsk);
1161                 tcp_done(newsk);
1162                 goto out;
1163         }
1164         *own_req = inet_ehash_nolisten(newsk, req_to_sk(req_unhash));
1165         if (*own_req) {
1166                 tcp_move_syn(newtp, req);
1167
1168                 /* Clone pktoptions received with SYN, if we own the req */
1169                 if (ireq->pktopts) {
1170                         newnp->pktoptions = skb_clone(ireq->pktopts,
1171                                                       sk_gfp_mask(sk, GFP_ATOMIC));
1172                         consume_skb(ireq->pktopts);
1173                         ireq->pktopts = NULL;
1174                         if (newnp->pktoptions)
1175                                 skb_set_owner_r(newnp->pktoptions, newsk);
1176                 }
1177         }
1178
1179         return newsk;
1180
1181 out_overflow:
1182         __NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
1183 out_nonewsk:
1184         dst_release(dst);
1185 out:
1186         tcp_listendrop(sk);
1187         return NULL;
1188 }
1189
1190 /* The socket must have it's spinlock held when we get
1191  * here, unless it is a TCP_LISTEN socket.
1192  *
1193  * We have a potential double-lock case here, so even when
1194  * doing backlog processing we use the BH locking scheme.
1195  * This is because we cannot sleep with the original spinlock
1196  * held.
1197  */
1198 static int tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb)
1199 {
1200         struct ipv6_pinfo *np = inet6_sk(sk);
1201         struct tcp_sock *tp;
1202         struct sk_buff *opt_skb = NULL;
1203
1204         /* Imagine: socket is IPv6. IPv4 packet arrives,
1205            goes to IPv4 receive handler and backlogged.
1206            From backlog it always goes here. Kerboom...
1207            Fortunately, tcp_rcv_established and rcv_established
1208            handle them correctly, but it is not case with
1209            tcp_v6_hnd_req and tcp_v6_send_reset().   --ANK
1210          */
1211
1212         if (skb->protocol == htons(ETH_P_IP))
1213                 return tcp_v4_do_rcv(sk, skb);
1214
1215         if (sk_filter(sk, skb))
1216                 goto discard;
1217
1218         /*
1219          *      socket locking is here for SMP purposes as backlog rcv
1220          *      is currently called with bh processing disabled.
1221          */
1222
1223         /* Do Stevens' IPV6_PKTOPTIONS.
1224
1225            Yes, guys, it is the only place in our code, where we
1226            may make it not affecting IPv4.
1227            The rest of code is protocol independent,
1228            and I do not like idea to uglify IPv4.
1229
1230            Actually, all the idea behind IPV6_PKTOPTIONS
1231            looks not very well thought. For now we latch
1232            options, received in the last packet, enqueued
1233            by tcp. Feel free to propose better solution.
1234                                                --ANK (980728)
1235          */
1236         if (np->rxopt.all)
1237                 opt_skb = skb_clone(skb, sk_gfp_mask(sk, GFP_ATOMIC));
1238
1239         if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
1240                 struct dst_entry *dst = sk->sk_rx_dst;
1241
1242                 sock_rps_save_rxhash(sk, skb);
1243                 sk_mark_napi_id(sk, skb);
1244                 if (dst) {
1245                         if (inet_sk(sk)->rx_dst_ifindex != skb->skb_iif ||
1246                             dst->ops->check(dst, np->rx_dst_cookie) == NULL) {
1247                                 dst_release(dst);
1248                                 sk->sk_rx_dst = NULL;
1249                         }
1250                 }
1251
1252                 tcp_rcv_established(sk, skb, tcp_hdr(skb), skb->len);
1253                 if (opt_skb)
1254                         goto ipv6_pktoptions;
1255                 return 0;
1256         }
1257
1258         if (tcp_checksum_complete(skb))
1259                 goto csum_err;
1260
1261         if (sk->sk_state == TCP_LISTEN) {
1262                 struct sock *nsk = tcp_v6_cookie_check(sk, skb);
1263
1264                 if (!nsk)
1265                         goto discard;
1266
1267                 if (nsk != sk) {
1268                         sock_rps_save_rxhash(nsk, skb);
1269                         sk_mark_napi_id(nsk, skb);
1270                         if (tcp_child_process(sk, nsk, skb))
1271                                 goto reset;
1272                         if (opt_skb)
1273                                 __kfree_skb(opt_skb);
1274                         return 0;
1275                 }
1276         } else
1277                 sock_rps_save_rxhash(sk, skb);
1278
1279         if (tcp_rcv_state_process(sk, skb))
1280                 goto reset;
1281         if (opt_skb)
1282                 goto ipv6_pktoptions;
1283         return 0;
1284
1285 reset:
1286         tcp_v6_send_reset(sk, skb);
1287 discard:
1288         if (opt_skb)
1289                 __kfree_skb(opt_skb);
1290         kfree_skb(skb);
1291         return 0;
1292 csum_err:
1293         TCP_INC_STATS(sock_net(sk), TCP_MIB_CSUMERRORS);
1294         TCP_INC_STATS(sock_net(sk), TCP_MIB_INERRS);
1295         goto discard;
1296
1297
1298 ipv6_pktoptions:
1299         /* Do you ask, what is it?
1300
1301            1. skb was enqueued by tcp.
1302            2. skb is added to tail of read queue, rather than out of order.
1303            3. socket is not in passive state.
1304            4. Finally, it really contains options, which user wants to receive.
1305          */
1306         tp = tcp_sk(sk);
1307         if (TCP_SKB_CB(opt_skb)->end_seq == tp->rcv_nxt &&
1308             !((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN))) {
1309                 if (np->rxopt.bits.rxinfo || np->rxopt.bits.rxoinfo)
1310                         np->mcast_oif = tcp_v6_iif(opt_skb);
1311                 if (np->rxopt.bits.rxhlim || np->rxopt.bits.rxohlim)
1312                         np->mcast_hops = ipv6_hdr(opt_skb)->hop_limit;
1313                 if (np->rxopt.bits.rxflow || np->rxopt.bits.rxtclass)
1314                         np->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(opt_skb));
1315                 if (np->repflow)
1316                         np->flow_label = ip6_flowlabel(ipv6_hdr(opt_skb));
1317                 if (ipv6_opt_accepted(sk, opt_skb, &TCP_SKB_CB(opt_skb)->header.h6)) {
1318                         skb_set_owner_r(opt_skb, sk);
1319                         opt_skb = xchg(&np->pktoptions, opt_skb);
1320                 } else {
1321                         __kfree_skb(opt_skb);
1322                         opt_skb = xchg(&np->pktoptions, NULL);
1323                 }
1324         }
1325
1326         kfree_skb(opt_skb);
1327         return 0;
1328 }
1329
1330 static void tcp_v6_fill_cb(struct sk_buff *skb, const struct ipv6hdr *hdr,
1331                            const struct tcphdr *th)
1332 {
1333         /* This is tricky: we move IP6CB at its correct location into
1334          * TCP_SKB_CB(). It must be done after xfrm6_policy_check(), because
1335          * _decode_session6() uses IP6CB().
1336          * barrier() makes sure compiler won't play aliasing games.
1337          */
1338         memmove(&TCP_SKB_CB(skb)->header.h6, IP6CB(skb),
1339                 sizeof(struct inet6_skb_parm));
1340         barrier();
1341
1342         TCP_SKB_CB(skb)->seq = ntohl(th->seq);
1343         TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
1344                                     skb->len - th->doff*4);
1345         TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
1346         TCP_SKB_CB(skb)->tcp_flags = tcp_flag_byte(th);
1347         TCP_SKB_CB(skb)->tcp_tw_isn = 0;
1348         TCP_SKB_CB(skb)->ip_dsfield = ipv6_get_dsfield(hdr);
1349         TCP_SKB_CB(skb)->sacked = 0;
1350 }
1351
1352 static void tcp_v6_restore_cb(struct sk_buff *skb)
1353 {
1354         /* We need to move header back to the beginning if xfrm6_policy_check()
1355          * and tcp_v6_fill_cb() are going to be called again.
1356          */
1357         memmove(IP6CB(skb), &TCP_SKB_CB(skb)->header.h6,
1358                 sizeof(struct inet6_skb_parm));
1359 }
1360
1361 static int tcp_v6_rcv(struct sk_buff *skb)
1362 {
1363         const struct tcphdr *th;
1364         const struct ipv6hdr *hdr;
1365         bool refcounted;
1366         struct sock *sk;
1367         int ret;
1368         struct net *net = dev_net(skb->dev);
1369
1370         if (skb->pkt_type != PACKET_HOST)
1371                 goto discard_it;
1372
1373         /*
1374          *      Count it even if it's bad.
1375          */
1376         __TCP_INC_STATS(net, TCP_MIB_INSEGS);
1377
1378         if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
1379                 goto discard_it;
1380
1381         th = (const struct tcphdr *)skb->data;
1382
1383         if (unlikely(th->doff < sizeof(struct tcphdr)/4))
1384                 goto bad_packet;
1385         if (!pskb_may_pull(skb, th->doff*4))
1386                 goto discard_it;
1387
1388         if (skb_checksum_init(skb, IPPROTO_TCP, ip6_compute_pseudo))
1389                 goto csum_error;
1390
1391         th = (const struct tcphdr *)skb->data;
1392         hdr = ipv6_hdr(skb);
1393
1394 lookup:
1395         sk = __inet6_lookup_skb(&tcp_hashinfo, skb, __tcp_hdrlen(th),
1396                                 th->source, th->dest, inet6_iif(skb),
1397                                 &refcounted);
1398         if (!sk)
1399                 goto no_tcp_socket;
1400
1401 process:
1402         if (sk->sk_state == TCP_TIME_WAIT)
1403                 goto do_time_wait;
1404
1405         if (sk->sk_state == TCP_NEW_SYN_RECV) {
1406                 struct request_sock *req = inet_reqsk(sk);
1407                 struct sock *nsk;
1408
1409                 sk = req->rsk_listener;
1410                 tcp_v6_fill_cb(skb, hdr, th);
1411                 if (tcp_v6_inbound_md5_hash(sk, skb)) {
1412                         reqsk_put(req);
1413                         goto discard_it;
1414                 }
1415                 if (unlikely(sk->sk_state != TCP_LISTEN)) {
1416                         inet_csk_reqsk_queue_drop_and_put(sk, req);
1417                         goto lookup;
1418                 }
1419                 sock_hold(sk);
1420                 refcounted = true;
1421                 nsk = tcp_check_req(sk, skb, req, false);
1422                 if (!nsk) {
1423                         reqsk_put(req);
1424                         goto discard_and_relse;
1425                 }
1426                 if (nsk == sk) {
1427                         reqsk_put(req);
1428                         tcp_v6_restore_cb(skb);
1429                 } else if (tcp_child_process(sk, nsk, skb)) {
1430                         tcp_v6_send_reset(nsk, skb);
1431                         goto discard_and_relse;
1432                 } else {
1433                         sock_put(sk);
1434                         return 0;
1435                 }
1436         }
1437         if (hdr->hop_limit < inet6_sk(sk)->min_hopcount) {
1438                 __NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP);
1439                 goto discard_and_relse;
1440         }
1441
1442         if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb))
1443                 goto discard_and_relse;
1444
1445         tcp_v6_fill_cb(skb, hdr, th);
1446
1447         if (tcp_v6_inbound_md5_hash(sk, skb))
1448                 goto discard_and_relse;
1449
1450         if (sk_filter(sk, skb))
1451                 goto discard_and_relse;
1452
1453         skb->dev = NULL;
1454
1455         if (sk->sk_state == TCP_LISTEN) {
1456                 ret = tcp_v6_do_rcv(sk, skb);
1457                 goto put_and_return;
1458         }
1459
1460         sk_incoming_cpu_update(sk);
1461
1462         bh_lock_sock_nested(sk);
1463         tcp_segs_in(tcp_sk(sk), skb);
1464         ret = 0;
1465         if (!sock_owned_by_user(sk)) {
1466                 if (!tcp_prequeue(sk, skb))
1467                         ret = tcp_v6_do_rcv(sk, skb);
1468         } else if (unlikely(sk_add_backlog(sk, skb,
1469                                            sk->sk_rcvbuf + sk->sk_sndbuf))) {
1470                 bh_unlock_sock(sk);
1471                 __NET_INC_STATS(net, LINUX_MIB_TCPBACKLOGDROP);
1472                 goto discard_and_relse;
1473         }
1474         bh_unlock_sock(sk);
1475
1476 put_and_return:
1477         if (refcounted)
1478                 sock_put(sk);
1479         return ret ? -1 : 0;
1480
1481 no_tcp_socket:
1482         if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb))
1483                 goto discard_it;
1484
1485         tcp_v6_fill_cb(skb, hdr, th);
1486
1487         if (tcp_checksum_complete(skb)) {
1488 csum_error:
1489                 __TCP_INC_STATS(net, TCP_MIB_CSUMERRORS);
1490 bad_packet:
1491                 __TCP_INC_STATS(net, TCP_MIB_INERRS);
1492         } else {
1493                 tcp_v6_send_reset(NULL, skb);
1494         }
1495
1496 discard_it:
1497         kfree_skb(skb);
1498         return 0;
1499
1500 discard_and_relse:
1501         sk_drops_add(sk, skb);
1502         if (refcounted)
1503                 sock_put(sk);
1504         goto discard_it;
1505
1506 do_time_wait:
1507         if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
1508                 inet_twsk_put(inet_twsk(sk));
1509                 goto discard_it;
1510         }
1511
1512         tcp_v6_fill_cb(skb, hdr, th);
1513
1514         if (tcp_checksum_complete(skb)) {
1515                 inet_twsk_put(inet_twsk(sk));
1516                 goto csum_error;
1517         }
1518
1519         switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) {
1520         case TCP_TW_SYN:
1521         {
1522                 struct sock *sk2;
1523
1524                 sk2 = inet6_lookup_listener(dev_net(skb->dev), &tcp_hashinfo,
1525                                             skb, __tcp_hdrlen(th),
1526                                             &ipv6_hdr(skb)->saddr, th->source,
1527                                             &ipv6_hdr(skb)->daddr,
1528                                             ntohs(th->dest), tcp_v6_iif(skb));
1529                 if (sk2) {
1530                         struct inet_timewait_sock *tw = inet_twsk(sk);
1531                         inet_twsk_deschedule_put(tw);
1532                         sk = sk2;
1533                         tcp_v6_restore_cb(skb);
1534                         refcounted = false;
1535                         goto process;
1536                 }
1537                 /* Fall through to ACK */
1538         }
1539         case TCP_TW_ACK:
1540                 tcp_v6_timewait_ack(sk, skb);
1541                 break;
1542         case TCP_TW_RST:
1543                 tcp_v6_restore_cb(skb);
1544                 tcp_v6_send_reset(sk, skb);
1545                 inet_twsk_deschedule_put(inet_twsk(sk));
1546                 goto discard_it;
1547         case TCP_TW_SUCCESS:
1548                 ;
1549         }
1550         goto discard_it;
1551 }
1552
1553 static void tcp_v6_early_demux(struct sk_buff *skb)
1554 {
1555         const struct ipv6hdr *hdr;
1556         const struct tcphdr *th;
1557         struct sock *sk;
1558
1559         if (skb->pkt_type != PACKET_HOST)
1560                 return;
1561
1562         if (!pskb_may_pull(skb, skb_transport_offset(skb) + sizeof(struct tcphdr)))
1563                 return;
1564
1565         hdr = ipv6_hdr(skb);
1566         th = tcp_hdr(skb);
1567
1568         if (th->doff < sizeof(struct tcphdr) / 4)
1569                 return;
1570
1571         /* Note : We use inet6_iif() here, not tcp_v6_iif() */
1572         sk = __inet6_lookup_established(dev_net(skb->dev), &tcp_hashinfo,
1573                                         &hdr->saddr, th->source,
1574                                         &hdr->daddr, ntohs(th->dest),
1575                                         inet6_iif(skb));
1576         if (sk) {
1577                 skb->sk = sk;
1578                 skb->destructor = sock_edemux;
1579                 if (sk_fullsock(sk)) {
1580                         struct dst_entry *dst = READ_ONCE(sk->sk_rx_dst);
1581
1582                         if (dst)
1583                                 dst = dst_check(dst, inet6_sk(sk)->rx_dst_cookie);
1584                         if (dst &&
1585                             inet_sk(sk)->rx_dst_ifindex == skb->skb_iif)
1586                                 skb_dst_set_noref(skb, dst);
1587                 }
1588         }
1589 }
1590
1591 static struct timewait_sock_ops tcp6_timewait_sock_ops = {
1592         .twsk_obj_size  = sizeof(struct tcp6_timewait_sock),
1593         .twsk_unique    = tcp_twsk_unique,
1594         .twsk_destructor = tcp_twsk_destructor,
1595 };
1596
1597 static const struct inet_connection_sock_af_ops ipv6_specific = {
1598         .queue_xmit        = inet6_csk_xmit,
1599         .send_check        = tcp_v6_send_check,
1600         .rebuild_header    = inet6_sk_rebuild_header,
1601         .sk_rx_dst_set     = inet6_sk_rx_dst_set,
1602         .conn_request      = tcp_v6_conn_request,
1603         .syn_recv_sock     = tcp_v6_syn_recv_sock,
1604         .net_header_len    = sizeof(struct ipv6hdr),
1605         .net_frag_header_len = sizeof(struct frag_hdr),
1606         .setsockopt        = ipv6_setsockopt,
1607         .getsockopt        = ipv6_getsockopt,
1608         .addr2sockaddr     = inet6_csk_addr2sockaddr,
1609         .sockaddr_len      = sizeof(struct sockaddr_in6),
1610         .bind_conflict     = inet6_csk_bind_conflict,
1611 #ifdef CONFIG_COMPAT
1612         .compat_setsockopt = compat_ipv6_setsockopt,
1613         .compat_getsockopt = compat_ipv6_getsockopt,
1614 #endif
1615         .mtu_reduced       = tcp_v6_mtu_reduced,
1616 };
1617
1618 #ifdef CONFIG_TCP_MD5SIG
1619 static const struct tcp_sock_af_ops tcp_sock_ipv6_specific = {
1620         .md5_lookup     =       tcp_v6_md5_lookup,
1621         .calc_md5_hash  =       tcp_v6_md5_hash_skb,
1622         .md5_parse      =       tcp_v6_parse_md5_keys,
1623 };
1624 #endif
1625
1626 /*
1627  *      TCP over IPv4 via INET6 API
1628  */
1629 static const struct inet_connection_sock_af_ops ipv6_mapped = {
1630         .queue_xmit        = ip_queue_xmit,
1631         .send_check        = tcp_v4_send_check,
1632         .rebuild_header    = inet_sk_rebuild_header,
1633         .sk_rx_dst_set     = inet_sk_rx_dst_set,
1634         .conn_request      = tcp_v6_conn_request,
1635         .syn_recv_sock     = tcp_v6_syn_recv_sock,
1636         .net_header_len    = sizeof(struct iphdr),
1637         .setsockopt        = ipv6_setsockopt,
1638         .getsockopt        = ipv6_getsockopt,
1639         .addr2sockaddr     = inet6_csk_addr2sockaddr,
1640         .sockaddr_len      = sizeof(struct sockaddr_in6),
1641         .bind_conflict     = inet6_csk_bind_conflict,
1642 #ifdef CONFIG_COMPAT
1643         .compat_setsockopt = compat_ipv6_setsockopt,
1644         .compat_getsockopt = compat_ipv6_getsockopt,
1645 #endif
1646         .mtu_reduced       = tcp_v4_mtu_reduced,
1647 };
1648
1649 #ifdef CONFIG_TCP_MD5SIG
1650 static const struct tcp_sock_af_ops tcp_sock_ipv6_mapped_specific = {
1651         .md5_lookup     =       tcp_v4_md5_lookup,
1652         .calc_md5_hash  =       tcp_v4_md5_hash_skb,
1653         .md5_parse      =       tcp_v6_parse_md5_keys,
1654 };
1655 #endif
1656
1657 /* NOTE: A lot of things set to zero explicitly by call to
1658  *       sk_alloc() so need not be done here.
1659  */
1660 static int tcp_v6_init_sock(struct sock *sk)
1661 {
1662         struct inet_connection_sock *icsk = inet_csk(sk);
1663
1664         tcp_init_sock(sk);
1665
1666         icsk->icsk_af_ops = &ipv6_specific;
1667
1668 #ifdef CONFIG_TCP_MD5SIG
1669         tcp_sk(sk)->af_specific = &tcp_sock_ipv6_specific;
1670 #endif
1671
1672         return 0;
1673 }
1674
1675 static void tcp_v6_destroy_sock(struct sock *sk)
1676 {
1677         tcp_v4_destroy_sock(sk);
1678         inet6_destroy_sock(sk);
1679 }
1680
1681 #ifdef CONFIG_PROC_FS
1682 /* Proc filesystem TCPv6 sock list dumping. */
1683 static void get_openreq6(struct seq_file *seq,
1684                          const struct request_sock *req, int i)
1685 {
1686         long ttd = req->rsk_timer.expires - jiffies;
1687         const struct in6_addr *src = &inet_rsk(req)->ir_v6_loc_addr;
1688         const struct in6_addr *dest = &inet_rsk(req)->ir_v6_rmt_addr;
1689
1690         if (ttd < 0)
1691                 ttd = 0;
1692
1693         seq_printf(seq,
1694                    "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
1695                    "%02X %08X:%08X %02X:%08lX %08X %5u %8d %d %d %pK\n",
1696                    i,
1697                    src->s6_addr32[0], src->s6_addr32[1],
1698                    src->s6_addr32[2], src->s6_addr32[3],
1699                    inet_rsk(req)->ir_num,
1700                    dest->s6_addr32[0], dest->s6_addr32[1],
1701                    dest->s6_addr32[2], dest->s6_addr32[3],
1702                    ntohs(inet_rsk(req)->ir_rmt_port),
1703                    TCP_SYN_RECV,
1704                    0, 0, /* could print option size, but that is af dependent. */
1705                    1,   /* timers active (only the expire timer) */
1706                    jiffies_to_clock_t(ttd),
1707                    req->num_timeout,
1708                    from_kuid_munged(seq_user_ns(seq),
1709                                     sock_i_uid(req->rsk_listener)),
1710                    0,  /* non standard timer */
1711                    0, /* open_requests have no inode */
1712                    0, req);
1713 }
1714
1715 static void get_tcp6_sock(struct seq_file *seq, struct sock *sp, int i)
1716 {
1717         const struct in6_addr *dest, *src;
1718         __u16 destp, srcp;
1719         int timer_active;
1720         unsigned long timer_expires;
1721         const struct inet_sock *inet = inet_sk(sp);
1722         const struct tcp_sock *tp = tcp_sk(sp);
1723         const struct inet_connection_sock *icsk = inet_csk(sp);
1724         const struct fastopen_queue *fastopenq = &icsk->icsk_accept_queue.fastopenq;
1725         int rx_queue;
1726         int state;
1727
1728         dest  = &sp->sk_v6_daddr;
1729         src   = &sp->sk_v6_rcv_saddr;
1730         destp = ntohs(inet->inet_dport);
1731         srcp  = ntohs(inet->inet_sport);
1732
1733         if (icsk->icsk_pending == ICSK_TIME_RETRANS ||
1734             icsk->icsk_pending == ICSK_TIME_EARLY_RETRANS ||
1735             icsk->icsk_pending == ICSK_TIME_LOSS_PROBE) {
1736                 timer_active    = 1;
1737                 timer_expires   = icsk->icsk_timeout;
1738         } else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
1739                 timer_active    = 4;
1740                 timer_expires   = icsk->icsk_timeout;
1741         } else if (timer_pending(&sp->sk_timer)) {
1742                 timer_active    = 2;
1743                 timer_expires   = sp->sk_timer.expires;
1744         } else {
1745                 timer_active    = 0;
1746                 timer_expires = jiffies;
1747         }
1748
1749         state = sk_state_load(sp);
1750         if (state == TCP_LISTEN)
1751                 rx_queue = sp->sk_ack_backlog;
1752         else
1753                 /* Because we don't lock the socket,
1754                  * we might find a transient negative value.
1755                  */
1756                 rx_queue = max_t(int, tp->rcv_nxt - tp->copied_seq, 0);
1757
1758         seq_printf(seq,
1759                    "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
1760                    "%02X %08X:%08X %02X:%08lX %08X %5u %8d %lu %d %pK %lu %lu %u %u %d\n",
1761                    i,
1762                    src->s6_addr32[0], src->s6_addr32[1],
1763                    src->s6_addr32[2], src->s6_addr32[3], srcp,
1764                    dest->s6_addr32[0], dest->s6_addr32[1],
1765                    dest->s6_addr32[2], dest->s6_addr32[3], destp,
1766                    state,
1767                    tp->write_seq - tp->snd_una,
1768                    rx_queue,
1769                    timer_active,
1770                    jiffies_delta_to_clock_t(timer_expires - jiffies),
1771                    icsk->icsk_retransmits,
1772                    from_kuid_munged(seq_user_ns(seq), sock_i_uid(sp)),
1773                    icsk->icsk_probes_out,
1774                    sock_i_ino(sp),
1775                    atomic_read(&sp->sk_refcnt), sp,
1776                    jiffies_to_clock_t(icsk->icsk_rto),
1777                    jiffies_to_clock_t(icsk->icsk_ack.ato),
1778                    (icsk->icsk_ack.quick << 1) | icsk->icsk_ack.pingpong,
1779                    tp->snd_cwnd,
1780                    state == TCP_LISTEN ?
1781                         fastopenq->max_qlen :
1782                         (tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh)
1783                    );
1784 }
1785
1786 static void get_timewait6_sock(struct seq_file *seq,
1787                                struct inet_timewait_sock *tw, int i)
1788 {
1789         long delta = tw->tw_timer.expires - jiffies;
1790         const struct in6_addr *dest, *src;
1791         __u16 destp, srcp;
1792
1793         dest = &tw->tw_v6_daddr;
1794         src  = &tw->tw_v6_rcv_saddr;
1795         destp = ntohs(tw->tw_dport);
1796         srcp  = ntohs(tw->tw_sport);
1797
1798         seq_printf(seq,
1799                    "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
1800                    "%02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK\n",
1801                    i,
1802                    src->s6_addr32[0], src->s6_addr32[1],
1803                    src->s6_addr32[2], src->s6_addr32[3], srcp,
1804                    dest->s6_addr32[0], dest->s6_addr32[1],
1805                    dest->s6_addr32[2], dest->s6_addr32[3], destp,
1806                    tw->tw_substate, 0, 0,
1807                    3, jiffies_delta_to_clock_t(delta), 0, 0, 0, 0,
1808                    atomic_read(&tw->tw_refcnt), tw);
1809 }
1810
1811 static int tcp6_seq_show(struct seq_file *seq, void *v)
1812 {
1813         struct tcp_iter_state *st;
1814         struct sock *sk = v;
1815
1816         if (v == SEQ_START_TOKEN) {
1817                 seq_puts(seq,
1818                          "  sl  "
1819                          "local_address                         "
1820                          "remote_address                        "
1821                          "st tx_queue rx_queue tr tm->when retrnsmt"
1822                          "   uid  timeout inode\n");
1823                 goto out;
1824         }
1825         st = seq->private;
1826
1827         if (sk->sk_state == TCP_TIME_WAIT)
1828                 get_timewait6_sock(seq, v, st->num);
1829         else if (sk->sk_state == TCP_NEW_SYN_RECV)
1830                 get_openreq6(seq, v, st->num);
1831         else
1832                 get_tcp6_sock(seq, v, st->num);
1833 out:
1834         return 0;
1835 }
1836
1837 static const struct file_operations tcp6_afinfo_seq_fops = {
1838         .owner   = THIS_MODULE,
1839         .open    = tcp_seq_open,
1840         .read    = seq_read,
1841         .llseek  = seq_lseek,
1842         .release = seq_release_net
1843 };
1844
1845 static struct tcp_seq_afinfo tcp6_seq_afinfo = {
1846         .name           = "tcp6",
1847         .family         = AF_INET6,
1848         .seq_fops       = &tcp6_afinfo_seq_fops,
1849         .seq_ops        = {
1850                 .show           = tcp6_seq_show,
1851         },
1852 };
1853
1854 int __net_init tcp6_proc_init(struct net *net)
1855 {
1856         return tcp_proc_register(net, &tcp6_seq_afinfo);
1857 }
1858
1859 void tcp6_proc_exit(struct net *net)
1860 {
1861         tcp_proc_unregister(net, &tcp6_seq_afinfo);
1862 }
1863 #endif
1864
1865 static void tcp_v6_clear_sk(struct sock *sk, int size)
1866 {
1867         struct inet_sock *inet = inet_sk(sk);
1868
1869         /* we do not want to clear pinet6 field, because of RCU lookups */
1870         sk_prot_clear_nulls(sk, offsetof(struct inet_sock, pinet6));
1871
1872         size -= offsetof(struct inet_sock, pinet6) + sizeof(inet->pinet6);
1873         memset(&inet->pinet6 + 1, 0, size);
1874 }
1875
1876 struct proto tcpv6_prot = {
1877         .name                   = "TCPv6",
1878         .owner                  = THIS_MODULE,
1879         .close                  = tcp_close,
1880         .connect                = tcp_v6_connect,
1881         .disconnect             = tcp_disconnect,
1882         .accept                 = inet_csk_accept,
1883         .ioctl                  = tcp_ioctl,
1884         .init                   = tcp_v6_init_sock,
1885         .destroy                = tcp_v6_destroy_sock,
1886         .shutdown               = tcp_shutdown,
1887         .setsockopt             = tcp_setsockopt,
1888         .getsockopt             = tcp_getsockopt,
1889         .recvmsg                = tcp_recvmsg,
1890         .sendmsg                = tcp_sendmsg,
1891         .sendpage               = tcp_sendpage,
1892         .backlog_rcv            = tcp_v6_do_rcv,
1893         .release_cb             = tcp_release_cb,
1894         .hash                   = inet6_hash,
1895         .unhash                 = inet_unhash,
1896         .get_port               = inet_csk_get_port,
1897         .enter_memory_pressure  = tcp_enter_memory_pressure,
1898         .stream_memory_free     = tcp_stream_memory_free,
1899         .sockets_allocated      = &tcp_sockets_allocated,
1900         .memory_allocated       = &tcp_memory_allocated,
1901         .memory_pressure        = &tcp_memory_pressure,
1902         .orphan_count           = &tcp_orphan_count,
1903         .sysctl_mem             = sysctl_tcp_mem,
1904         .sysctl_wmem            = sysctl_tcp_wmem,
1905         .sysctl_rmem            = sysctl_tcp_rmem,
1906         .max_header             = MAX_TCP_HEADER,
1907         .obj_size               = sizeof(struct tcp6_sock),
1908         .slab_flags             = SLAB_DESTROY_BY_RCU,
1909         .twsk_prot              = &tcp6_timewait_sock_ops,
1910         .rsk_prot               = &tcp6_request_sock_ops,
1911         .h.hashinfo             = &tcp_hashinfo,
1912         .no_autobind            = true,
1913 #ifdef CONFIG_COMPAT
1914         .compat_setsockopt      = compat_tcp_setsockopt,
1915         .compat_getsockopt      = compat_tcp_getsockopt,
1916 #endif
1917         .clear_sk               = tcp_v6_clear_sk,
1918         .diag_destroy           = tcp_abort,
1919 };
1920
1921 static const struct inet6_protocol tcpv6_protocol = {
1922         .early_demux    =       tcp_v6_early_demux,
1923         .handler        =       tcp_v6_rcv,
1924         .err_handler    =       tcp_v6_err,
1925         .flags          =       INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
1926 };
1927
1928 static struct inet_protosw tcpv6_protosw = {
1929         .type           =       SOCK_STREAM,
1930         .protocol       =       IPPROTO_TCP,
1931         .prot           =       &tcpv6_prot,
1932         .ops            =       &inet6_stream_ops,
1933         .flags          =       INET_PROTOSW_PERMANENT |
1934                                 INET_PROTOSW_ICSK,
1935 };
1936
1937 static int __net_init tcpv6_net_init(struct net *net)
1938 {
1939         return inet_ctl_sock_create(&net->ipv6.tcp_sk, PF_INET6,
1940                                     SOCK_RAW, IPPROTO_TCP, net);
1941 }
1942
1943 static void __net_exit tcpv6_net_exit(struct net *net)
1944 {
1945         inet_ctl_sock_destroy(net->ipv6.tcp_sk);
1946 }
1947
1948 static void __net_exit tcpv6_net_exit_batch(struct list_head *net_exit_list)
1949 {
1950         inet_twsk_purge(&tcp_hashinfo, &tcp_death_row, AF_INET6);
1951 }
1952
1953 static struct pernet_operations tcpv6_net_ops = {
1954         .init       = tcpv6_net_init,
1955         .exit       = tcpv6_net_exit,
1956         .exit_batch = tcpv6_net_exit_batch,
1957 };
1958
1959 int __init tcpv6_init(void)
1960 {
1961         int ret;
1962
1963         ret = inet6_add_protocol(&tcpv6_protocol, IPPROTO_TCP);
1964         if (ret)
1965                 goto out;
1966
1967         /* register inet6 protocol */
1968         ret = inet6_register_protosw(&tcpv6_protosw);
1969         if (ret)
1970                 goto out_tcpv6_protocol;
1971
1972         ret = register_pernet_subsys(&tcpv6_net_ops);
1973         if (ret)
1974                 goto out_tcpv6_protosw;
1975 out:
1976         return ret;
1977
1978 out_tcpv6_protosw:
1979         inet6_unregister_protosw(&tcpv6_protosw);
1980 out_tcpv6_protocol:
1981         inet6_del_protocol(&tcpv6_protocol, IPPROTO_TCP);
1982         goto out;
1983 }
1984
1985 void tcpv6_exit(void)
1986 {
1987         unregister_pernet_subsys(&tcpv6_net_ops);
1988         inet6_unregister_protosw(&tcpv6_protosw);
1989         inet6_del_protocol(&tcpv6_protocol, IPPROTO_TCP);
1990 }