net/ipv6/tcp_ipv6.c

   1 /*
   2  *      TCP over IPv6
   3  *      Linux INET6 implementation
   4  *
   5  *      Authors:
   6  *      Pedro Roque             <roque@di.fc.ul.pt>
   7  *
   8  *      Based on:
   9  *      linux/net/ipv4/tcp.c
  10  *      linux/net/ipv4/tcp_input.c
  11  *      linux/net/ipv4/tcp_output.c
  12  *
  13  *      Fixes:
  14  *      Hideaki YOSHIFUJI       :       sin6_scope_id support
  15  *      YOSHIFUJI Hideaki @USAGI and:   Support IPV6_V6ONLY socket option, which
  16  *      Alexey Kuznetsov                allow both IPv4 and IPv6 sockets to bind
  17  *                                      a single port at the same time.
  18  *      YOSHIFUJI Hideaki @USAGI:       convert /proc/net/tcp6 to seq_file.
  19  *
  20  *      This program is free software; you can redistribute it and/or
  21  *      modify it under the terms of the GNU General Public License
  22  *      as published by the Free Software Foundation; either version
  23  *      2 of the License, or (at your option) any later version.
  24  */
  25
  26 #include <linux/bottom_half.h>
  27 #include <linux/module.h>
  28 #include <linux/errno.h>
  29 #include <linux/types.h>
  30 #include <linux/socket.h>
  31 #include <linux/sockios.h>
  32 #include <linux/net.h>
  33 #include <linux/jiffies.h>
  34 #include <linux/in.h>
  35 #include <linux/in6.h>
  36 #include <linux/netdevice.h>
  37 #include <linux/init.h>
  38 #include <linux/jhash.h>
  39 #include <linux/ipsec.h>
  40 #include <linux/times.h>
  41 #include <linux/slab.h>
  42 #include <linux/uaccess.h>
  43 #include <linux/ipv6.h>
  44 #include <linux/icmpv6.h>
  45 #include <linux/random.h>
  46
  47 #include <net/tcp.h>
  48 #include <net/ndisc.h>
  49 #include <net/inet6_hashtables.h>
  50 #include <net/inet6_connection_sock.h>
  51 #include <net/ipv6.h>
  52 #include <net/transp_v6.h>
  53 #include <net/addrconf.h>
  54 #include <net/ip6_route.h>
  55 #include <net/ip6_checksum.h>
  56 #include <net/inet_ecn.h>
  57 #include <net/protocol.h>
  58 #include <net/xfrm.h>
  59 #include <net/snmp.h>
  60 #include <net/dsfield.h>
  61 #include <net/timewait_sock.h>
  62 #include <net/inet_common.h>
  63 #include <net/secure_seq.h>
  64 #include <net/tcp_memcontrol.h>
  65 #include <net/busy_poll.h>
  66
  67 #include <linux/proc_fs.h>
  68 #include <linux/seq_file.h>
  69
  70 #include <linux/crypto.h>
  71 #include <linux/scatterlist.h>
  72
  73 static void     tcp_v6_send_reset(const struct sock *sk, struct sk_buff *skb);
  74 static void     tcp_v6_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb,
  75                                       struct request_sock *req);
  76
  77 static int      tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb);
  78
  79 static const struct inet_connection_sock_af_ops ipv6_mapped;
  80 static const struct inet_connection_sock_af_ops ipv6_specific;
  81 #ifdef CONFIG_TCP_MD5SIG
  82 static const struct tcp_sock_af_ops tcp_sock_ipv6_specific;
  83 static const struct tcp_sock_af_ops tcp_sock_ipv6_mapped_specific;
  84 #else
  85 static struct tcp_md5sig_key *tcp_v6_md5_do_lookup(const struct sock *sk,
  86                                                    const struct in6_addr *addr)
  87 {
  88         return NULL;
  89 }
  90 #endif
  91
  92 static void inet6_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb)
  93 {
  94         struct dst_entry *dst = skb_dst(skb);
  95
  96         if (dst && dst_hold_safe(dst)) {
  97                 const struct rt6_info *rt = (const struct rt6_info *)dst;
  98
  99                 sk->sk_rx_dst = dst;
 100                 inet_sk(sk)->rx_dst_ifindex = skb->skb_iif;
 101                 inet6_sk(sk)->rx_dst_cookie = rt6_get_cookie(rt);
 102         }
 103 }
 104
 105 static __u32 tcp_v6_init_sequence(const struct sk_buff *skb)
 106 {
 107         return secure_tcpv6_sequence_number(ipv6_hdr(skb)->daddr.s6_addr32,
 108                                             ipv6_hdr(skb)->saddr.s6_addr32,
 109                                             tcp_hdr(skb)->dest,
 110                                             tcp_hdr(skb)->source);
 111 }
 112
 113 static int tcp_v6_connect(struct sock *sk, struct sockaddr *uaddr,
 114                           int addr_len)
 115 {
 116         struct sockaddr_in6 *usin = (struct sockaddr_in6 *) uaddr;
 117         struct inet_sock *inet = inet_sk(sk);
 118         struct inet_connection_sock *icsk = inet_csk(sk);
 119         struct ipv6_pinfo *np = inet6_sk(sk);
 120         struct tcp_sock *tp = tcp_sk(sk);
 121         struct in6_addr *saddr = NULL, *final_p, final;
 122         struct ipv6_txoptions *opt;
 123         struct flowi6 fl6;
 124         struct dst_entry *dst;
 125         int addr_type;
 126         int err;
 127
 128         if (addr_len < SIN6_LEN_RFC2133)
 129                 return -EINVAL;
 130
 131         if (usin->sin6_family != AF_INET6)
 132                 return -EAFNOSUPPORT;
 133
 134         memset(&fl6, 0, sizeof(fl6));
 135
 136         if (np->sndflow) {
 137                 fl6.flowlabel = usin->sin6_flowinfo&IPV6_FLOWINFO_MASK;
 138                 IP6_ECN_flow_init(fl6.flowlabel);
 139                 if (fl6.flowlabel&IPV6_FLOWLABEL_MASK) {
 140                         struct ip6_flowlabel *flowlabel;
 141                         flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
 142                         if (!flowlabel)
 143                                 return -EINVAL;
 144                         fl6_sock_release(flowlabel);
 145                 }
 146         }
 147
 148         /*
 149          *      connect() to INADDR_ANY means loopback (BSD'ism).
 150          */
 151
 152         if (ipv6_addr_any(&usin->sin6_addr))
 153                 usin->sin6_addr.s6_addr[15] = 0x1;
 154
 155         addr_type = ipv6_addr_type(&usin->sin6_addr);
 156
 157         if (addr_type & IPV6_ADDR_MULTICAST)
 158                 return -ENETUNREACH;
 159
 160         if (addr_type&IPV6_ADDR_LINKLOCAL) {
 161                 if (addr_len >= sizeof(struct sockaddr_in6) &&
 162                     usin->sin6_scope_id) {
 163                         /* If interface is set while binding, indices
 164                          * must coincide.
 165                          */
 166                         if (sk->sk_bound_dev_if &&
 167                             sk->sk_bound_dev_if != usin->sin6_scope_id)
 168                                 return -EINVAL;
 169
 170                         sk->sk_bound_dev_if = usin->sin6_scope_id;
 171                 }
 172
 173                 /* Connect to link-local address requires an interface */
 174                 if (!sk->sk_bound_dev_if)
 175                         return -EINVAL;
 176         }
 177
 178         if (tp->rx_opt.ts_recent_stamp &&
 179             !ipv6_addr_equal(&sk->sk_v6_daddr, &usin->sin6_addr)) {
 180                 tp->rx_opt.ts_recent = 0;
 181                 tp->rx_opt.ts_recent_stamp = 0;
 182                 tp->write_seq = 0;
 183         }
 184
 185         sk->sk_v6_daddr = usin->sin6_addr;
 186         np->flow_label = fl6.flowlabel;
 187
 188         /*
 189          *      TCP over IPv4
 190          */
 191
 192         if (addr_type == IPV6_ADDR_MAPPED) {
 193                 u32 exthdrlen = icsk->icsk_ext_hdr_len;
 194                 struct sockaddr_in sin;
 195
 196                 SOCK_DEBUG(sk, "connect: ipv4 mapped\n");
 197
 198                 if (__ipv6_only_sock(sk))
 199                         return -ENETUNREACH;
 200
 201                 sin.sin_family = AF_INET;
 202                 sin.sin_port = usin->sin6_port;
 203                 sin.sin_addr.s_addr = usin->sin6_addr.s6_addr32[3];
 204
 205                 icsk->icsk_af_ops = &ipv6_mapped;
 206                 sk->sk_backlog_rcv = tcp_v4_do_rcv;
 207 #ifdef CONFIG_TCP_MD5SIG
 208                 tp->af_specific = &tcp_sock_ipv6_mapped_specific;
 209 #endif
 210
 211                 err = tcp_v4_connect(sk, (struct sockaddr *)&sin, sizeof(sin));
 212
 213                 if (err) {
 214                         icsk->icsk_ext_hdr_len = exthdrlen;
 215                         icsk->icsk_af_ops = &ipv6_specific;
 216                         sk->sk_backlog_rcv = tcp_v6_do_rcv;
 217 #ifdef CONFIG_TCP_MD5SIG
 218                         tp->af_specific = &tcp_sock_ipv6_specific;
 219 #endif
 220                         goto failure;
 221                 }
 222                 np->saddr = sk->sk_v6_rcv_saddr;
 223
 224                 return err;
 225         }
 226
 227         if (!ipv6_addr_any(&sk->sk_v6_rcv_saddr))
 228                 saddr = &sk->sk_v6_rcv_saddr;
 229
 230         fl6.flowi6_proto = IPPROTO_TCP;
 231         fl6.daddr = sk->sk_v6_daddr;
 232         fl6.saddr = saddr ? *saddr : np->saddr;
 233         fl6.flowi6_oif = sk->sk_bound_dev_if;
 234         fl6.flowi6_mark = sk->sk_mark;
 235         fl6.fl6_dport = usin->sin6_port;
 236         fl6.fl6_sport = inet->inet_sport;
 237
 238         opt = rcu_dereference_protected(np->opt, sock_owned_by_user(sk));
 239         final_p = fl6_update_dst(&fl6, opt, &final);
 240
 241         security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));
 242
 243         dst = ip6_dst_lookup_flow(sk, &fl6, final_p);
 244         if (IS_ERR(dst)) {
 245                 err = PTR_ERR(dst);
 246                 goto failure;
 247         }
 248
 249         if (!saddr) {
 250                 saddr = &fl6.saddr;
 251                 sk->sk_v6_rcv_saddr = *saddr;
 252         }
 253
 254         /* set the source address */
 255         np->saddr = *saddr;
 256         inet->inet_rcv_saddr = LOOPBACK4_IPV6;
 257
 258         sk->sk_gso_type = SKB_GSO_TCPV6;
 259         ip6_dst_store(sk, dst, NULL, NULL);
 260
 261         if (tcp_death_row.sysctl_tw_recycle &&
 262             !tp->rx_opt.ts_recent_stamp &&
 263             ipv6_addr_equal(&fl6.daddr, &sk->sk_v6_daddr))
 264                 tcp_fetch_timewait_stamp(sk, dst);
 265
 266         icsk->icsk_ext_hdr_len = 0;
 267         if (opt)
 268                 icsk->icsk_ext_hdr_len = opt->opt_flen +
 269                                          opt->opt_nflen;
 270
 271         tp->rx_opt.mss_clamp = IPV6_MIN_MTU - sizeof(struct tcphdr) - sizeof(struct ipv6hdr);
 272
 273         inet->inet_dport = usin->sin6_port;
 274
 275         tcp_set_state(sk, TCP_SYN_SENT);
 276         err = inet6_hash_connect(&tcp_death_row, sk);
 277         if (err)
 278                 goto late_failure;
 279
 280         sk_set_txhash(sk);
 281
 282         if (!tp->write_seq && likely(!tp->repair))
 283                 tp->write_seq = secure_tcpv6_sequence_number(np->saddr.s6_addr32,
 284                                                              sk->sk_v6_daddr.s6_addr32,
 285                                                              inet->inet_sport,
 286                                                              inet->inet_dport);
 287
 288         err = tcp_connect(sk);
 289         if (err)
 290                 goto late_failure;
 291
 292         return 0;
 293
 294 late_failure:
 295         tcp_set_state(sk, TCP_CLOSE);
 296         __sk_dst_reset(sk);
 297 failure:
 298         inet->inet_dport = 0;
 299         sk->sk_route_caps = 0;
 300         return err;
 301 }
 302
 303 static void tcp_v6_mtu_reduced(struct sock *sk)
 304 {
 305         struct dst_entry *dst;
 306
 307         if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE))
 308                 return;
 309
 310         dst = inet6_csk_update_pmtu(sk, tcp_sk(sk)->mtu_info);
 311         if (!dst)
 312                 return;
 313
 314         if (inet_csk(sk)->icsk_pmtu_cookie > dst_mtu(dst)) {
 315                 tcp_sync_mss(sk, dst_mtu(dst));
 316                 tcp_simple_retransmit(sk);
 317         }
 318 }
 319
 320 static void tcp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 321                 u8 type, u8 code, int offset, __be32 info)
 322 {
 323         const struct ipv6hdr *hdr = (const struct ipv6hdr *)skb->data;
 324         const struct tcphdr *th = (struct tcphdr *)(skb->data+offset);
 325         struct net *net = dev_net(skb->dev);
 326         struct request_sock *fastopen;
 327         struct ipv6_pinfo *np;
 328         struct tcp_sock *tp;
 329         __u32 seq, snd_una;
 330         struct sock *sk;
 331         bool fatal;
 332         int err;
 333
 334         sk = __inet6_lookup_established(net, &tcp_hashinfo,
 335                                         &hdr->daddr, th->dest,
 336                                         &hdr->saddr, ntohs(th->source),
 337                                         skb->dev->ifindex);
 338
 339         if (!sk) {
 340                 ICMP6_INC_STATS_BH(net, __in6_dev_get(skb->dev),
 341                                    ICMP6_MIB_INERRORS);
 342                 return;
 343         }
 344
 345         if (sk->sk_state == TCP_TIME_WAIT) {
 346                 inet_twsk_put(inet_twsk(sk));
 347                 return;
 348         }
 349         seq = ntohl(th->seq);
 350         fatal = icmpv6_err_convert(type, code, &err);
 351         if (sk->sk_state == TCP_NEW_SYN_RECV)
 352                 return tcp_req_err(sk, seq, fatal);
 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
 407         /* Might be for an request_sock */
 408         switch (sk->sk_state) {
 409         case TCP_SYN_SENT:
 410         case TCP_SYN_RECV:
 411                 /* Only in fast or simultaneous open. If a fast open socket is
 412                  * is already accepted it is treated as a connected one below.
 413                  */
 414                 if (fastopen && !fastopen->sk)
 415                         break;
 416
 417                 if (!sock_owned_by_user(sk)) {
 418                         sk->sk_err = err;
 419                         sk->sk_error_report(sk);                /* Wake people up to see the error (see connect in sock.c) */
 420
 421                         tcp_done(sk);
 422                 } else
 423                         sk->sk_err_soft = err;
 424                 goto out;
 425         }
 426
 427         if (!sock_owned_by_user(sk) && np->recverr) {
 428                 sk->sk_err = err;
 429                 sk->sk_error_report(sk);
 430         } else
 431                 sk->sk_err_soft = err;
 432
 433 out:
 434         bh_unlock_sock(sk);
 435         sock_put(sk);
 436 }
 437
 438
 439 static int tcp_v6_send_synack(const struct sock *sk, struct dst_entry *dst,
 440                               struct flowi *fl,
 441                               struct request_sock *req,
 442                               struct tcp_fastopen_cookie *foc,
 443                               bool attach_req)
 444 {
 445         struct inet_request_sock *ireq = inet_rsk(req);
 446         struct ipv6_pinfo *np = inet6_sk(sk);
 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, attach_req);
 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                 err = ip6_xmit(sk, skb, fl6, rcu_dereference(np->opt),
 468                                np->tclass);
 469                 rcu_read_unlock();
 470                 err = net_xmit_eval(err);
 471         }
 472
 473 done:
 474         return err;
 475 }
 476
 477
 478 static void tcp_v6_reqsk_destructor(struct request_sock *req)
 479 {
 480         kfree_skb(inet_rsk(req)->pktopts);
 481 }
 482
 483 #ifdef CONFIG_TCP_MD5SIG
 484 static struct tcp_md5sig_key *tcp_v6_md5_do_lookup(const struct sock *sk,
 485                                                    const struct in6_addr *addr)
 486 {
 487         return tcp_md5_do_lookup(sk, (union tcp_md5_addr *)addr, AF_INET6);
 488 }
 489
 490 static struct tcp_md5sig_key *tcp_v6_md5_lookup(const struct sock *sk,
 491                                                 const struct sock *addr_sk)
 492 {
 493         return tcp_v6_md5_do_lookup(sk, &addr_sk->sk_v6_daddr);
 494 }
 495
 496 static int tcp_v6_parse_md5_keys(struct sock *sk, char __user *optval,
 497                                  int optlen)
 498 {
 499         struct tcp_md5sig cmd;
 500         struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)&cmd.tcpm_addr;
 501
 502         if (optlen < sizeof(cmd))
 503                 return -EINVAL;
 504
 505         if (copy_from_user(&cmd, optval, sizeof(cmd)))
 506                 return -EFAULT;
 507
 508         if (sin6->sin6_family != AF_INET6)
 509                 return -EINVAL;
 510
 511         if (!cmd.tcpm_keylen) {
 512                 if (ipv6_addr_v4mapped(&sin6->sin6_addr))
 513                         return tcp_md5_do_del(sk, (union tcp_md5_addr *)&sin6->sin6_addr.s6_addr32[3],
 514                                               AF_INET);
 515                 return tcp_md5_do_del(sk, (union tcp_md5_addr *)&sin6->sin6_addr,
 516                                       AF_INET6);
 517         }
 518
 519         if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN)
 520                 return -EINVAL;
 521
 522         if (ipv6_addr_v4mapped(&sin6->sin6_addr))
 523                 return tcp_md5_do_add(sk, (union tcp_md5_addr *)&sin6->sin6_addr.s6_addr32[3],
 524                                       AF_INET, cmd.tcpm_key, cmd.tcpm_keylen, GFP_KERNEL);
 525
 526         return tcp_md5_do_add(sk, (union tcp_md5_addr *)&sin6->sin6_addr,
 527                               AF_INET6, cmd.tcpm_key, cmd.tcpm_keylen, GFP_KERNEL);
 528 }
 529
 530 static int tcp_v6_md5_hash_pseudoheader(struct tcp_md5sig_pool *hp,
 531                                         const struct in6_addr *daddr,
 532                                         const struct in6_addr *saddr, int nbytes)
 533 {
 534         struct tcp6_pseudohdr *bp;
 535         struct scatterlist sg;
 536
 537         bp = &hp->md5_blk.ip6;
 538         /* 1. TCP pseudo-header (RFC2460) */
 539         bp->saddr = *saddr;
 540         bp->daddr = *daddr;
 541         bp->protocol = cpu_to_be32(IPPROTO_TCP);
 542         bp->len = cpu_to_be32(nbytes);
 543
 544         sg_init_one(&sg, bp, sizeof(*bp));
 545         return crypto_hash_update(&hp->md5_desc, &sg, sizeof(*bp));
 546 }
 547
 548 static int tcp_v6_md5_hash_hdr(char *md5_hash, struct tcp_md5sig_key *key,
 549                                const struct in6_addr *daddr, struct in6_addr *saddr,
 550                                const struct tcphdr *th)
 551 {
 552         struct tcp_md5sig_pool *hp;
 553         struct hash_desc *desc;
 554
 555         hp = tcp_get_md5sig_pool();
 556         if (!hp)
 557                 goto clear_hash_noput;
 558         desc = &hp->md5_desc;
 559
 560         if (crypto_hash_init(desc))
 561                 goto clear_hash;
 562         if (tcp_v6_md5_hash_pseudoheader(hp, daddr, saddr, th->doff << 2))
 563                 goto clear_hash;
 564         if (tcp_md5_hash_header(hp, th))
 565                 goto clear_hash;
 566         if (tcp_md5_hash_key(hp, key))
 567                 goto clear_hash;
 568         if (crypto_hash_final(desc, md5_hash))
 569                 goto clear_hash;
 570
 571         tcp_put_md5sig_pool();
 572         return 0;
 573
 574 clear_hash:
 575         tcp_put_md5sig_pool();
 576 clear_hash_noput:
 577         memset(md5_hash, 0, 16);
 578         return 1;
 579 }
 580
 581 static int tcp_v6_md5_hash_skb(char *md5_hash,
 582                                const struct tcp_md5sig_key *key,
 583                                const struct sock *sk,
 584                                const struct sk_buff *skb)
 585 {
 586         const struct in6_addr *saddr, *daddr;
 587         struct tcp_md5sig_pool *hp;
 588         struct hash_desc *desc;
 589         const struct tcphdr *th = tcp_hdr(skb);
 590
 591         if (sk) { /* valid for establish/request sockets */
 592                 saddr = &sk->sk_v6_rcv_saddr;
 593                 daddr = &sk->sk_v6_daddr;
 594         } else {
 595                 const struct ipv6hdr *ip6h = ipv6_hdr(skb);
 596                 saddr = &ip6h->saddr;
 597                 daddr = &ip6h->daddr;
 598         }
 599
 600         hp = tcp_get_md5sig_pool();
 601         if (!hp)
 602                 goto clear_hash_noput;
 603         desc = &hp->md5_desc;
 604
 605         if (crypto_hash_init(desc))
 606                 goto clear_hash;
 607
 608         if (tcp_v6_md5_hash_pseudoheader(hp, daddr, saddr, skb->len))
 609                 goto clear_hash;
 610         if (tcp_md5_hash_header(hp, th))
 611                 goto clear_hash;
 612         if (tcp_md5_hash_skb_data(hp, skb, th->doff << 2))
 613                 goto clear_hash;
 614         if (tcp_md5_hash_key(hp, key))
 615                 goto clear_hash;
 616         if (crypto_hash_final(desc, md5_hash))
 617                 goto clear_hash;
 618
 619         tcp_put_md5sig_pool();
 620         return 0;
 621
 622 clear_hash:
 623         tcp_put_md5sig_pool();
 624 clear_hash_noput:
 625         memset(md5_hash, 0, 16);
 626         return 1;
 627 }
 628
 629 #endif
 630
 631 static bool tcp_v6_inbound_md5_hash(const struct sock *sk,
 632                                     const struct sk_buff *skb)
 633 {
 634 #ifdef CONFIG_TCP_MD5SIG
 635         const __u8 *hash_location = NULL;
 636         struct tcp_md5sig_key *hash_expected;
 637         const struct ipv6hdr *ip6h = ipv6_hdr(skb);
 638         const struct tcphdr *th = tcp_hdr(skb);
 639         int genhash;
 640         u8 newhash[16];
 641
 642         hash_expected = tcp_v6_md5_do_lookup(sk, &ip6h->saddr);
 643         hash_location = tcp_parse_md5sig_option(th);
 644
 645         /* We've parsed the options - do we have a hash? */
 646         if (!hash_expected && !hash_location)
 647                 return false;
 648
 649         if (hash_expected && !hash_location) {
 650                 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5NOTFOUND);
 651                 return true;
 652         }
 653
 654         if (!hash_expected && hash_location) {
 655                 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5UNEXPECTED);
 656                 return true;
 657         }
 658
 659         /* check the signature */
 660         genhash = tcp_v6_md5_hash_skb(newhash,
 661                                       hash_expected,
 662                                       NULL, skb);
 663
 664         if (genhash || memcmp(hash_location, newhash, 16) != 0) {
 665                 net_info_ratelimited("MD5 Hash %s for [%pI6c]:%u->[%pI6c]:%u\n",
 666                                      genhash ? "failed" : "mismatch",
 667                                      &ip6h->saddr, ntohs(th->source),
 668                                      &ip6h->daddr, ntohs(th->dest));
 669                 return true;
 670         }
 671 #endif
 672         return false;
 673 }
 674
 675 static void tcp_v6_init_req(struct request_sock *req,
 676                             const struct sock *sk_listener,
 677                             struct sk_buff *skb)
 678 {
 679         struct inet_request_sock *ireq = inet_rsk(req);
 680         const struct ipv6_pinfo *np = inet6_sk(sk_listener);
 681
 682         ireq->ir_v6_rmt_addr = ipv6_hdr(skb)->saddr;
 683         ireq->ir_v6_loc_addr = ipv6_hdr(skb)->daddr;
 684
 685         /* So that link locals have meaning */
 686         if (!sk_listener->sk_bound_dev_if &&
 687             ipv6_addr_type(&ireq->ir_v6_rmt_addr) & IPV6_ADDR_LINKLOCAL)
 688                 ireq->ir_iif = tcp_v6_iif(skb);
 689
 690         if (!TCP_SKB_CB(skb)->tcp_tw_isn &&
 691             (ipv6_opt_accepted(sk_listener, skb, &TCP_SKB_CB(skb)->header.h6) ||
 692              np->rxopt.bits.rxinfo ||
 693              np->rxopt.bits.rxoinfo || np->rxopt.bits.rxhlim ||
 694              np->rxopt.bits.rxohlim || np->repflow)) {
 695                 atomic_inc(&skb->users);
 696                 ireq->pktopts = skb;
 697         }
 698 }
 699
 700 static struct dst_entry *tcp_v6_route_req(const struct sock *sk,
 701                                           struct flowi *fl,
 702                                           const struct request_sock *req,
 703                                           bool *strict)
 704 {
 705         if (strict)
 706                 *strict = true;
 707         return inet6_csk_route_req(sk, &fl->u.ip6, req, IPPROTO_TCP);
 708 }
 709
 710 struct request_sock_ops tcp6_request_sock_ops __read_mostly = {
 711         .family         =       AF_INET6,
 712         .obj_size       =       sizeof(struct tcp6_request_sock),
 713         .rtx_syn_ack    =       tcp_rtx_synack,
 714         .send_ack       =       tcp_v6_reqsk_send_ack,
 715         .destructor     =       tcp_v6_reqsk_destructor,
 716         .send_reset     =       tcp_v6_send_reset,
 717         .syn_ack_timeout =      tcp_syn_ack_timeout,
 718 };
 719
 720 static const struct tcp_request_sock_ops tcp_request_sock_ipv6_ops = {
 721         .mss_clamp      =       IPV6_MIN_MTU - sizeof(struct tcphdr) -
 722                                 sizeof(struct ipv6hdr),
 723 #ifdef CONFIG_TCP_MD5SIG
 724         .req_md5_lookup =       tcp_v6_md5_lookup,
 725         .calc_md5_hash  =       tcp_v6_md5_hash_skb,
 726 #endif
 727         .init_req       =       tcp_v6_init_req,
 728 #ifdef CONFIG_SYN_COOKIES
 729         .cookie_init_seq =      cookie_v6_init_sequence,
 730 #endif
 731         .route_req      =       tcp_v6_route_req,
 732         .init_seq       =       tcp_v6_init_sequence,
 733         .send_synack    =       tcp_v6_send_synack,
 734 };
 735
 736 static void tcp_v6_send_response(const struct sock *sk, struct sk_buff *skb, u32 seq,
 737                                  u32 ack, u32 win, u32 tsval, u32 tsecr,
 738                                  int oif, struct tcp_md5sig_key *key, int rst,
 739                                  u8 tclass, u32 label)
 740 {
 741         const struct tcphdr *th = tcp_hdr(skb);
 742         struct tcphdr *t1;
 743         struct sk_buff *buff;
 744         struct flowi6 fl6;
 745         struct net *net = sk ? sock_net(sk) : dev_net(skb_dst(skb)->dev);
 746         struct sock *ctl_sk = net->ipv6.tcp_sk;
 747         unsigned int tot_len = sizeof(struct tcphdr);
 748         struct dst_entry *dst;
 749         __be32 *topt;
 750
 751         if (tsecr)
 752                 tot_len += TCPOLEN_TSTAMP_ALIGNED;
 753 #ifdef CONFIG_TCP_MD5SIG
 754         if (key)
 755                 tot_len += TCPOLEN_MD5SIG_ALIGNED;
 756 #endif
 757
 758         buff = alloc_skb(MAX_HEADER + sizeof(struct ipv6hdr) + tot_len,
 759                          GFP_ATOMIC);
 760         if (!buff)
 761                 return;
 762
 763         skb_reserve(buff, MAX_HEADER + sizeof(struct ipv6hdr) + tot_len);
 764
 765         t1 = (struct tcphdr *) skb_push(buff, tot_len);
 766         skb_reset_transport_header(buff);
 767
 768         /* Swap the send and the receive. */
 769         memset(t1, 0, sizeof(*t1));
 770         t1->dest = th->source;
 771         t1->source = th->dest;
 772         t1->doff = tot_len / 4;
 773         t1->seq = htonl(seq);
 774         t1->ack_seq = htonl(ack);
 775         t1->ack = !rst || !th->ack;
 776         t1->rst = rst;
 777         t1->window = htons(win);
 778
 779         topt = (__be32 *)(t1 + 1);
 780
 781         if (tsecr) {
 782                 *topt++ = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
 783                                 (TCPOPT_TIMESTAMP << 8) | TCPOLEN_TIMESTAMP);
 784                 *topt++ = htonl(tsval);
 785                 *topt++ = htonl(tsecr);
 786         }
 787
 788 #ifdef CONFIG_TCP_MD5SIG
 789         if (key) {
 790                 *topt++ = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
 791                                 (TCPOPT_MD5SIG << 8) | TCPOLEN_MD5SIG);
 792                 tcp_v6_md5_hash_hdr((__u8 *)topt, key,
 793                                     &ipv6_hdr(skb)->saddr,
 794                                     &ipv6_hdr(skb)->daddr, t1);
 795         }
 796 #endif
 797
 798         memset(&fl6, 0, sizeof(fl6));
 799         fl6.daddr = ipv6_hdr(skb)->saddr;
 800         fl6.saddr = ipv6_hdr(skb)->daddr;
 801         fl6.flowlabel = label;
 802
 803         buff->ip_summed = CHECKSUM_PARTIAL;
 804         buff->csum = 0;
 805
 806         __tcp_v6_send_check(buff, &fl6.saddr, &fl6.daddr);
 807
 808         fl6.flowi6_proto = IPPROTO_TCP;
 809         if (rt6_need_strict(&fl6.daddr) && !oif)
 810                 fl6.flowi6_oif = tcp_v6_iif(skb);
 811         else
 812                 fl6.flowi6_oif = oif;
 813         fl6.flowi6_mark = IP6_REPLY_MARK(net, skb->mark);
 814         fl6.fl6_dport = t1->dest;
 815         fl6.fl6_sport = t1->source;
 816         security_skb_classify_flow(skb, flowi6_to_flowi(&fl6));
 817
 818         /* Pass a socket to ip6_dst_lookup either it is for RST
 819          * Underlying function will use this to retrieve the network
 820          * namespace
 821          */
 822         dst = ip6_dst_lookup_flow(ctl_sk, &fl6, NULL);
 823         if (!IS_ERR(dst)) {
 824                 skb_dst_set(buff, dst);
 825                 ip6_xmit(ctl_sk, buff, &fl6, NULL, tclass);
 826                 TCP_INC_STATS_BH(net, TCP_MIB_OUTSEGS);
 827                 if (rst)
 828                         TCP_INC_STATS_BH(net, TCP_MIB_OUTRSTS);
 829                 return;
 830         }
 831
 832         kfree_skb(buff);
 833 }
 834
 835 static void tcp_v6_send_reset(const struct sock *sk, struct sk_buff *skb)
 836 {
 837         const struct tcphdr *th = tcp_hdr(skb);
 838         u32 seq = 0, ack_seq = 0;
 839         struct tcp_md5sig_key *key = NULL;
 840 #ifdef CONFIG_TCP_MD5SIG
 841         const __u8 *hash_location = NULL;
 842         struct ipv6hdr *ipv6h = ipv6_hdr(skb);
 843         unsigned char newhash[16];
 844         int genhash;
 845         struct sock *sk1 = NULL;
 846 #endif
 847         int oif;
 848
 849         if (th->rst)
 850                 return;
 851
 852         /* If sk not NULL, it means we did a successful lookup and incoming
 853          * route had to be correct. prequeue might have dropped our dst.
 854          */
 855         if (!sk && !ipv6_unicast_destination(skb))
 856                 return;
 857
 858 #ifdef CONFIG_TCP_MD5SIG
 859         hash_location = tcp_parse_md5sig_option(th);
 860         if (!sk && hash_location) {
 861                 /*
 862                  * active side is lost. Try to find listening socket through
 863                  * source port, and then find md5 key through listening socket.
 864                  * we are not loose security here:
 865                  * Incoming packet is checked with md5 hash with finding key,
 866                  * no RST generated if md5 hash doesn't match.
 867                  */
 868                 sk1 = inet6_lookup_listener(dev_net(skb_dst(skb)->dev),
 869                                            &tcp_hashinfo, &ipv6h->saddr,
 870                                            th->source, &ipv6h->daddr,
 871                                            ntohs(th->source), tcp_v6_iif(skb));
 872                 if (!sk1)
 873                         return;
 874
 875                 rcu_read_lock();
 876                 key = tcp_v6_md5_do_lookup(sk1, &ipv6h->saddr);
 877                 if (!key)
 878                         goto release_sk1;
 879
 880                 genhash = tcp_v6_md5_hash_skb(newhash, key, NULL, skb);
 881                 if (genhash || memcmp(hash_location, newhash, 16) != 0)
 882                         goto release_sk1;
 883         } else {
 884                 key = sk ? tcp_v6_md5_do_lookup(sk, &ipv6h->saddr) : NULL;
 885         }
 886 #endif
 887
 888         if (th->ack)
 889                 seq = ntohl(th->ack_seq);
 890         else
 891                 ack_seq = ntohl(th->seq) + th->syn + th->fin + skb->len -
 892                           (th->doff << 2);
 893
 894         oif = sk ? sk->sk_bound_dev_if : 0;
 895         tcp_v6_send_response(sk, skb, seq, ack_seq, 0, 0, 0, oif, key, 1, 0, 0);
 896
 897 #ifdef CONFIG_TCP_MD5SIG
 898 release_sk1:
 899         if (sk1) {
 900                 rcu_read_unlock();
 901                 sock_put(sk1);
 902         }
 903 #endif
 904 }
 905
 906 static void tcp_v6_send_ack(const struct sock *sk, struct sk_buff *skb, u32 seq,
 907                             u32 ack, u32 win, u32 tsval, u32 tsecr, int oif,
 908                             struct tcp_md5sig_key *key, u8 tclass,
 909                             u32 label)
 910 {
 911         tcp_v6_send_response(sk, skb, seq, ack, win, tsval, tsecr, oif, key, 0,
 912                              tclass, label);
 913 }
 914
 915 static void tcp_v6_timewait_ack(struct sock *sk, struct sk_buff *skb)
 916 {
 917         struct inet_timewait_sock *tw = inet_twsk(sk);
 918         struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
 919
 920         tcp_v6_send_ack(sk, skb, tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
 921                         tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
 922                         tcp_time_stamp + tcptw->tw_ts_offset,
 923                         tcptw->tw_ts_recent, tw->tw_bound_dev_if, tcp_twsk_md5_key(tcptw),
 924                         tw->tw_tclass, cpu_to_be32(tw->tw_flowlabel));
 925
 926         inet_twsk_put(tw);
 927 }
 928
 929 static void tcp_v6_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb,
 930                                   struct request_sock *req)
 931 {
 932         /* sk->sk_state == TCP_LISTEN -> for regular TCP_SYN_RECV
 933          * sk->sk_state == TCP_SYN_RECV -> for Fast Open.
 934          */
 935         /* RFC 7323 2.3
 936          * The window field (SEG.WND) of every outgoing segment, with the
 937          * exception of <SYN> segments, MUST be right-shifted by
 938          * Rcv.Wind.Shift bits:
 939          */
 940         tcp_v6_send_ack(sk, skb, (sk->sk_state == TCP_LISTEN) ?
 941                         tcp_rsk(req)->snt_isn + 1 : tcp_sk(sk)->snd_nxt,
 942                         tcp_rsk(req)->rcv_nxt,
 943                         req->rsk_rcv_wnd >> inet_rsk(req)->rcv_wscale,
 944                         tcp_time_stamp, req->ts_recent, sk->sk_bound_dev_if,
 945                         tcp_v6_md5_do_lookup(sk, &ipv6_hdr(skb)->daddr),
 946                         0, 0);
 947 }
 948
 949
 950 static struct sock *tcp_v6_cookie_check(struct sock *sk, struct sk_buff *skb)
 951 {
 952 #ifdef CONFIG_SYN_COOKIES
 953         const struct tcphdr *th = tcp_hdr(skb);
 954
 955         if (!th->syn)
 956                 sk = cookie_v6_check(sk, skb);
 957 #endif
 958         return sk;
 959 }
 960
 961 static int tcp_v6_conn_request(struct sock *sk, struct sk_buff *skb)
 962 {
 963         if (skb->protocol == htons(ETH_P_IP))
 964                 return tcp_v4_conn_request(sk, skb);
 965
 966         if (!ipv6_unicast_destination(skb))
 967                 goto drop;
 968
 969         return tcp_conn_request(&tcp6_request_sock_ops,
 970                                 &tcp_request_sock_ipv6_ops, sk, skb);
 971
 972 drop:
 973         NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
 974         return 0; /* don't send reset */
 975 }
 976
 977 static struct sock *tcp_v6_syn_recv_sock(const struct sock *sk, struct sk_buff *skb,
 978                                          struct request_sock *req,
 979                                          struct dst_entry *dst,
 980                                          struct request_sock *req_unhash,
 981                                          bool *own_req)
 982 {
 983         struct inet_request_sock *ireq;
 984         struct ipv6_pinfo *newnp;
 985         const struct ipv6_pinfo *np = inet6_sk(sk);
 986         struct ipv6_txoptions *opt;
 987         struct tcp6_sock *newtcp6sk;
 988         struct inet_sock *newinet;
 989         struct tcp_sock *newtp;
 990         struct sock *newsk;
 991 #ifdef CONFIG_TCP_MD5SIG
 992         struct tcp_md5sig_key *key;
 993 #endif
 994         struct flowi6 fl6;
 995
 996         if (skb->protocol == htons(ETH_P_IP)) {
 997                 /*
 998                  *      v6 mapped
 999                  */
1000
1001                 newsk = tcp_v4_syn_recv_sock(sk, skb, req, dst,
1002                                              req_unhash, own_req);
1003
1004                 if (!newsk)
1005                         return NULL;
1006
1007                 newtcp6sk = (struct tcp6_sock *)newsk;
1008                 inet_sk(newsk)->pinet6 = &newtcp6sk->inet6;
1009
1010                 newinet = inet_sk(newsk);
1011                 newnp = inet6_sk(newsk);
1012                 newtp = tcp_sk(newsk);
1013
1014                 memcpy(newnp, np, sizeof(struct ipv6_pinfo));
1015
1016                 newnp->saddr = newsk->sk_v6_rcv_saddr;
1017
1018                 inet_csk(newsk)->icsk_af_ops = &ipv6_mapped;
1019                 newsk->sk_backlog_rcv = tcp_v4_do_rcv;
1020 #ifdef CONFIG_TCP_MD5SIG
1021                 newtp->af_specific = &tcp_sock_ipv6_mapped_specific;
1022 #endif
1023
1024                 newnp->ipv6_ac_list = NULL;
1025                 newnp->ipv6_fl_list = NULL;
1026                 newnp->pktoptions  = NULL;
1027                 newnp->opt         = NULL;
1028                 newnp->mcast_oif   = tcp_v6_iif(skb);
1029                 newnp->mcast_hops  = ipv6_hdr(skb)->hop_limit;
1030                 newnp->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(skb));
1031                 if (np->repflow)
1032                         newnp->flow_label = ip6_flowlabel(ipv6_hdr(skb));
1033
1034                 /*
1035                  * No need to charge this sock to the relevant IPv6 refcnt debug socks count
1036                  * here, tcp_create_openreq_child now does this for us, see the comment in
1037                  * that function for the gory details. -acme
1038                  */
1039
1040                 /* It is tricky place. Until this moment IPv4 tcp
1041                    worked with IPv6 icsk.icsk_af_ops.
1042                    Sync it now.
1043                  */
1044                 tcp_sync_mss(newsk, inet_csk(newsk)->icsk_pmtu_cookie);
1045
1046                 return newsk;
1047         }
1048
1049         ireq = inet_rsk(req);
1050
1051         if (sk_acceptq_is_full(sk))
1052                 goto out_overflow;
1053
1054         if (!dst) {
1055                 dst = inet6_csk_route_req(sk, &fl6, req, IPPROTO_TCP);
1056                 if (!dst)
1057                         goto out;
1058         }
1059
1060         newsk = tcp_create_openreq_child(sk, req, skb);
1061         if (!newsk)
1062                 goto out_nonewsk;
1063
1064         /*
1065          * No need to charge this sock to the relevant IPv6 refcnt debug socks
1066          * count here, tcp_create_openreq_child now does this for us, see the
1067          * comment in that function for the gory details. -acme
1068          */
1069
1070         newsk->sk_gso_type = SKB_GSO_TCPV6;
1071         ip6_dst_store(newsk, dst, NULL, NULL);
1072         inet6_sk_rx_dst_set(newsk, skb);
1073
1074         newtcp6sk = (struct tcp6_sock *)newsk;
1075         inet_sk(newsk)->pinet6 = &newtcp6sk->inet6;
1076
1077         newtp = tcp_sk(newsk);
1078         newinet = inet_sk(newsk);
1079         newnp = inet6_sk(newsk);
1080
1081         memcpy(newnp, np, sizeof(struct ipv6_pinfo));
1082
1083         newsk->sk_v6_daddr = ireq->ir_v6_rmt_addr;
1084         newnp->saddr = ireq->ir_v6_loc_addr;
1085         newsk->sk_v6_rcv_saddr = ireq->ir_v6_loc_addr;
1086         newsk->sk_bound_dev_if = ireq->ir_iif;
1087
1088         /* Now IPv6 options...
1089
1090            First: no IPv4 options.
1091          */
1092         newinet->inet_opt = NULL;
1093         newnp->ipv6_ac_list = NULL;
1094         newnp->ipv6_fl_list = NULL;
1095
1096         /* Clone RX bits */
1097         newnp->rxopt.all = np->rxopt.all;
1098
1099         newnp->pktoptions = NULL;
1100         newnp->opt        = NULL;
1101         newnp->mcast_oif  = tcp_v6_iif(skb);
1102         newnp->mcast_hops = ipv6_hdr(skb)->hop_limit;
1103         newnp->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(skb));
1104         if (np->repflow)
1105                 newnp->flow_label = ip6_flowlabel(ipv6_hdr(skb));
1106
1107         /* Clone native IPv6 options from listening socket (if any)
1108
1109            Yes, keeping reference count would be much more clever,
1110            but we make one more one thing there: reattach optmem
1111            to newsk.
1112          */
1113         opt = rcu_dereference(np->opt);
1114         if (opt) {
1115                 opt = ipv6_dup_options(newsk, opt);
1116                 RCU_INIT_POINTER(newnp->opt, opt);
1117         }
1118         inet_csk(newsk)->icsk_ext_hdr_len = 0;
1119         if (opt)
1120                 inet_csk(newsk)->icsk_ext_hdr_len = opt->opt_nflen +
1121                                                     opt->opt_flen;
1122
1123         tcp_ca_openreq_child(newsk, dst);
1124
1125         tcp_sync_mss(newsk, dst_mtu(dst));
1126         newtp->advmss = dst_metric_advmss(dst);
1127         if (tcp_sk(sk)->rx_opt.user_mss &&
1128             tcp_sk(sk)->rx_opt.user_mss < newtp->advmss)
1129                 newtp->advmss = tcp_sk(sk)->rx_opt.user_mss;
1130
1131         tcp_initialize_rcv_mss(newsk);
1132
1133         newinet->inet_daddr = newinet->inet_saddr = LOOPBACK4_IPV6;
1134         newinet->inet_rcv_saddr = LOOPBACK4_IPV6;
1135
1136 #ifdef CONFIG_TCP_MD5SIG
1137         /* Copy over the MD5 key from the original socket */
1138         key = tcp_v6_md5_do_lookup(sk, &newsk->sk_v6_daddr);
1139         if (key) {
1140                 /* We're using one, so create a matching key
1141                  * on the newsk structure. If we fail to get
1142                  * memory, then we end up not copying the key
1143                  * across. Shucks.
1144                  */
1145                 tcp_md5_do_add(newsk, (union tcp_md5_addr *)&newsk->sk_v6_daddr,
1146                                AF_INET6, key->key, key->keylen,
1147                                sk_gfp_atomic(sk, GFP_ATOMIC));
1148         }
1149 #endif
1150
1151         if (__inet_inherit_port(sk, newsk) < 0) {
1152                 inet_csk_prepare_forced_close(newsk);
1153                 tcp_done(newsk);
1154                 goto out;
1155         }
1156         *own_req = inet_ehash_nolisten(newsk, req_to_sk(req_unhash));
1157         if (*own_req) {
1158                 tcp_move_syn(newtp, req);
1159
1160                 /* Clone pktoptions received with SYN, if we own the req */
1161                 if (ireq->pktopts) {
1162                         newnp->pktoptions = skb_clone(ireq->pktopts,
1163                                                       sk_gfp_atomic(sk, GFP_ATOMIC));
1164                         consume_skb(ireq->pktopts);
1165                         ireq->pktopts = NULL;
1166                         if (newnp->pktoptions)
1167                                 skb_set_owner_r(newnp->pktoptions, newsk);
1168                 }
1169         }
1170
1171         return newsk;
1172
1173 out_overflow:
1174         NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
1175 out_nonewsk:
1176         dst_release(dst);
1177 out:
1178         NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
1179         return NULL;
1180 }
1181
1182 /* The socket must have it's spinlock held when we get
1183  * here, unless it is a TCP_LISTEN socket.
1184  *
1185  * We have a potential double-lock case here, so even when
1186  * doing backlog processing we use the BH locking scheme.
1187  * This is because we cannot sleep with the original spinlock
1188  * held.
1189  */
1190 static int tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb)
1191 {
1192         struct ipv6_pinfo *np = inet6_sk(sk);
1193         struct tcp_sock *tp;
1194         struct sk_buff *opt_skb = NULL;
1195
1196         /* Imagine: socket is IPv6. IPv4 packet arrives,
1197            goes to IPv4 receive handler and backlogged.
1198            From backlog it always goes here. Kerboom...
1199            Fortunately, tcp_rcv_established and rcv_established
1200            handle them correctly, but it is not case with
1201            tcp_v6_hnd_req and tcp_v6_send_reset().   --ANK
1202          */
1203
1204         if (skb->protocol == htons(ETH_P_IP))
1205                 return tcp_v4_do_rcv(sk, skb);
1206
1207         if (sk_filter(sk, skb))
1208                 goto discard;
1209
1210         /*
1211          *      socket locking is here for SMP purposes as backlog rcv
1212          *      is currently called with bh processing disabled.
1213          */
1214
1215         /* Do Stevens' IPV6_PKTOPTIONS.
1216
1217            Yes, guys, it is the only place in our code, where we
1218            may make it not affecting IPv4.
1219            The rest of code is protocol independent,
1220            and I do not like idea to uglify IPv4.
1221
1222            Actually, all the idea behind IPV6_PKTOPTIONS
1223            looks not very well thought. For now we latch
1224            options, received in the last packet, enqueued
1225            by tcp. Feel free to propose better solution.
1226                                                --ANK (980728)
1227          */
1228         if (np->rxopt.all)
1229                 opt_skb = skb_clone(skb, sk_gfp_atomic(sk, GFP_ATOMIC));
1230
1231         if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
1232                 struct dst_entry *dst = sk->sk_rx_dst;
1233
1234                 sock_rps_save_rxhash(sk, skb);
1235                 sk_mark_napi_id(sk, skb);
1236                 if (dst) {
1237                         if (inet_sk(sk)->rx_dst_ifindex != skb->skb_iif ||
1238                             dst->ops->check(dst, np->rx_dst_cookie) == NULL) {
1239                                 dst_release(dst);
1240                                 sk->sk_rx_dst = NULL;
1241                         }
1242                 }
1243
1244                 tcp_rcv_established(sk, skb, tcp_hdr(skb), skb->len);
1245                 if (opt_skb)
1246                         goto ipv6_pktoptions;
1247                 return 0;
1248         }
1249
1250         if (tcp_checksum_complete(skb))
1251                 goto csum_err;
1252
1253         if (sk->sk_state == TCP_LISTEN) {
1254                 struct sock *nsk = tcp_v6_cookie_check(sk, skb);
1255
1256                 if (!nsk)
1257                         goto discard;
1258
1259                 if (nsk != sk) {
1260                         sock_rps_save_rxhash(nsk, skb);
1261                         sk_mark_napi_id(nsk, skb);
1262                         if (tcp_child_process(sk, nsk, skb))
1263                                 goto reset;
1264                         if (opt_skb)
1265                                 __kfree_skb(opt_skb);
1266                         return 0;
1267                 }
1268         } else
1269                 sock_rps_save_rxhash(sk, skb);
1270
1271         if (tcp_rcv_state_process(sk, skb))
1272                 goto reset;
1273         if (opt_skb)
1274                 goto ipv6_pktoptions;
1275         return 0;
1276
1277 reset:
1278         tcp_v6_send_reset(sk, skb);
1279 discard:
1280         if (opt_skb)
1281                 __kfree_skb(opt_skb);
1282         kfree_skb(skb);
1283         return 0;
1284 csum_err:
1285         TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_CSUMERRORS);
1286         TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_INERRS);
1287         goto discard;
1288
1289
1290 ipv6_pktoptions:
1291         /* Do you ask, what is it?
1292
1293            1. skb was enqueued by tcp.
1294            2. skb is added to tail of read queue, rather than out of order.
1295            3. socket is not in passive state.
1296            4. Finally, it really contains options, which user wants to receive.
1297          */
1298         tp = tcp_sk(sk);
1299         if (TCP_SKB_CB(opt_skb)->end_seq == tp->rcv_nxt &&
1300             !((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN))) {
1301                 if (np->rxopt.bits.rxinfo || np->rxopt.bits.rxoinfo)
1302                         np->mcast_oif = tcp_v6_iif(opt_skb);
1303                 if (np->rxopt.bits.rxhlim || np->rxopt.bits.rxohlim)
1304                         np->mcast_hops = ipv6_hdr(opt_skb)->hop_limit;
1305                 if (np->rxopt.bits.rxflow || np->rxopt.bits.rxtclass)
1306                         np->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(opt_skb));
1307                 if (np->repflow)
1308                         np->flow_label = ip6_flowlabel(ipv6_hdr(opt_skb));
1309                 if (ipv6_opt_accepted(sk, opt_skb, &TCP_SKB_CB(opt_skb)->header.h6)) {
1310                         skb_set_owner_r(opt_skb, sk);
1311                         opt_skb = xchg(&np->pktoptions, opt_skb);
1312                 } else {
1313                         __kfree_skb(opt_skb);
1314                         opt_skb = xchg(&np->pktoptions, NULL);
1315                 }
1316         }
1317
1318         kfree_skb(opt_skb);
1319         return 0;
1320 }
1321
1322 static void tcp_v6_fill_cb(struct sk_buff *skb, const struct ipv6hdr *hdr,
1323                            const struct tcphdr *th)
1324 {
1325         /* This is tricky: we move IP6CB at its correct location into
1326          * TCP_SKB_CB(). It must be done after xfrm6_policy_check(), because
1327          * _decode_session6() uses IP6CB().
1328          * barrier() makes sure compiler won't play aliasing games.
1329          */
1330         memmove(&TCP_SKB_CB(skb)->header.h6, IP6CB(skb),
1331                 sizeof(struct inet6_skb_parm));
1332         barrier();
1333
1334         TCP_SKB_CB(skb)->seq = ntohl(th->seq);
1335         TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
1336                                     skb->len - th->doff*4);
1337         TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
1338         TCP_SKB_CB(skb)->tcp_flags = tcp_flag_byte(th);
1339         TCP_SKB_CB(skb)->tcp_tw_isn = 0;
1340         TCP_SKB_CB(skb)->ip_dsfield = ipv6_get_dsfield(hdr);
1341         TCP_SKB_CB(skb)->sacked = 0;
1342 }
1343
1344 static void tcp_v6_restore_cb(struct sk_buff *skb)
1345 {
1346         /* We need to move header back to the beginning if xfrm6_policy_check()
1347          * and tcp_v6_fill_cb() are going to be called again.
1348          */
1349         memmove(IP6CB(skb), &TCP_SKB_CB(skb)->header.h6,
1350                 sizeof(struct inet6_skb_parm));
1351 }
1352
1353 static int tcp_v6_rcv(struct sk_buff *skb)
1354 {
1355         const struct tcphdr *th;
1356         const struct ipv6hdr *hdr;
1357         struct sock *sk;
1358         int ret;
1359         struct net *net = dev_net(skb->dev);
1360
1361         if (skb->pkt_type != PACKET_HOST)
1362                 goto discard_it;
1363
1364         /*
1365          *      Count it even if it's bad.
1366          */
1367         TCP_INC_STATS_BH(net, TCP_MIB_INSEGS);
1368
1369         if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
1370                 goto discard_it;
1371
1372         th = tcp_hdr(skb);
1373
1374         if (th->doff < sizeof(struct tcphdr)/4)
1375                 goto bad_packet;
1376         if (!pskb_may_pull(skb, th->doff*4))
1377                 goto discard_it;
1378
1379         if (skb_checksum_init(skb, IPPROTO_TCP, ip6_compute_pseudo))
1380                 goto csum_error;
1381
1382         th = tcp_hdr(skb);
1383         hdr = ipv6_hdr(skb);
1384
1385 lookup:
1386         sk = __inet6_lookup_skb(&tcp_hashinfo, skb, th->source, th->dest,
1387                                 inet6_iif(skb));
1388         if (!sk)
1389                 goto no_tcp_socket;
1390
1391 process:
1392         if (sk->sk_state == TCP_TIME_WAIT)
1393                 goto do_time_wait;
1394
1395         if (sk->sk_state == TCP_NEW_SYN_RECV) {
1396                 struct request_sock *req = inet_reqsk(sk);
1397                 struct sock *nsk;
1398
1399                 sk = req->rsk_listener;
1400                 tcp_v6_fill_cb(skb, hdr, th);
1401                 if (tcp_v6_inbound_md5_hash(sk, skb)) {
1402                         reqsk_put(req);
1403                         goto discard_it;
1404                 }
1405                 if (unlikely(sk->sk_state != TCP_LISTEN)) {
1406                         inet_csk_reqsk_queue_drop_and_put(sk, req);
1407                         goto lookup;
1408                 }
1409                 sock_hold(sk);
1410                 nsk = tcp_check_req(sk, skb, req, false);
1411                 if (!nsk) {
1412                         reqsk_put(req);
1413                         goto discard_and_relse;
1414                 }
1415                 if (nsk == sk) {
1416                         reqsk_put(req);
1417                         tcp_v6_restore_cb(skb);
1418                 } else if (tcp_child_process(sk, nsk, skb)) {
1419                         tcp_v6_send_reset(nsk, skb);
1420                         goto discard_and_relse;
1421                 } else {
1422                         sock_put(sk);
1423                         return 0;
1424                 }
1425         }
1426         if (hdr->hop_limit < inet6_sk(sk)->min_hopcount) {
1427                 NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP);
1428                 goto discard_and_relse;
1429         }
1430
1431         if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb))
1432                 goto discard_and_relse;
1433
1434         tcp_v6_fill_cb(skb, hdr, th);
1435
1436         if (tcp_v6_inbound_md5_hash(sk, skb))
1437                 goto discard_and_relse;
1438
1439         if (sk_filter(sk, skb))
1440                 goto discard_and_relse;
1441
1442         skb->dev = NULL;
1443
1444         if (sk->sk_state == TCP_LISTEN) {
1445                 ret = tcp_v6_do_rcv(sk, skb);
1446                 goto put_and_return;
1447         }
1448
1449         sk_incoming_cpu_update(sk);
1450
1451         bh_lock_sock_nested(sk);
1452         tcp_sk(sk)->segs_in += max_t(u16, 1, skb_shinfo(skb)->gso_segs);
1453         ret = 0;
1454         if (!sock_owned_by_user(sk)) {
1455                 if (!tcp_prequeue(sk, skb))
1456                         ret = tcp_v6_do_rcv(sk, skb);
1457         } else if (unlikely(sk_add_backlog(sk, skb,
1458                                            sk->sk_rcvbuf + sk->sk_sndbuf))) {
1459                 bh_unlock_sock(sk);
1460                 NET_INC_STATS_BH(net, LINUX_MIB_TCPBACKLOGDROP);
1461                 goto discard_and_relse;
1462         }
1463         bh_unlock_sock(sk);
1464
1465 put_and_return:
1466         sock_put(sk);
1467         return ret ? -1 : 0;
1468
1469 no_tcp_socket:
1470         if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb))
1471                 goto discard_it;
1472
1473         tcp_v6_fill_cb(skb, hdr, th);
1474
1475         if (tcp_checksum_complete(skb)) {
1476 csum_error:
1477                 TCP_INC_STATS_BH(net, TCP_MIB_CSUMERRORS);
1478 bad_packet:
1479                 TCP_INC_STATS_BH(net, TCP_MIB_INERRS);
1480         } else {
1481                 tcp_v6_send_reset(NULL, skb);
1482         }
1483
1484 discard_it:
1485         kfree_skb(skb);
1486         return 0;
1487
1488 discard_and_relse:
1489         sock_put(sk);
1490         goto discard_it;
1491
1492 do_time_wait:
1493         if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
1494                 inet_twsk_put(inet_twsk(sk));
1495                 goto discard_it;
1496         }
1497
1498         tcp_v6_fill_cb(skb, hdr, th);
1499
1500         if (tcp_checksum_complete(skb)) {
1501                 inet_twsk_put(inet_twsk(sk));
1502                 goto csum_error;
1503         }
1504
1505         switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) {
1506         case TCP_TW_SYN:
1507         {
1508                 struct sock *sk2;
1509
1510                 sk2 = inet6_lookup_listener(dev_net(skb->dev), &tcp_hashinfo,
1511                                             &ipv6_hdr(skb)->saddr, th->source,
1512                                             &ipv6_hdr(skb)->daddr,
1513                                             ntohs(th->dest), tcp_v6_iif(skb));
1514                 if (sk2) {
1515                         struct inet_timewait_sock *tw = inet_twsk(sk);
1516                         inet_twsk_deschedule_put(tw);
1517                         sk = sk2;
1518                         tcp_v6_restore_cb(skb);
1519                         goto process;
1520                 }
1521                 /* Fall through to ACK */
1522         }
1523         case TCP_TW_ACK:
1524                 tcp_v6_timewait_ack(sk, skb);
1525                 break;
1526         case TCP_TW_RST:
1527                 tcp_v6_restore_cb(skb);
1528                 goto no_tcp_socket;
1529         case TCP_TW_SUCCESS:
1530                 ;
1531         }
1532         goto discard_it;
1533 }
1534
1535 static void tcp_v6_early_demux(struct sk_buff *skb)
1536 {
1537         const struct ipv6hdr *hdr;
1538         const struct tcphdr *th;
1539         struct sock *sk;
1540
1541         if (skb->pkt_type != PACKET_HOST)
1542                 return;
1543
1544         if (!pskb_may_pull(skb, skb_transport_offset(skb) + sizeof(struct tcphdr)))
1545                 return;
1546
1547         hdr = ipv6_hdr(skb);
1548         th = tcp_hdr(skb);
1549
1550         if (th->doff < sizeof(struct tcphdr) / 4)
1551                 return;
1552
1553         /* Note : We use inet6_iif() here, not tcp_v6_iif() */
1554         sk = __inet6_lookup_established(dev_net(skb->dev), &tcp_hashinfo,
1555                                         &hdr->saddr, th->source,
1556                                         &hdr->daddr, ntohs(th->dest),
1557                                         inet6_iif(skb));
1558         if (sk) {
1559                 skb->sk = sk;
1560                 skb->destructor = sock_edemux;
1561                 if (sk_fullsock(sk)) {
1562                         struct dst_entry *dst = READ_ONCE(sk->sk_rx_dst);
1563
1564                         if (dst)
1565                                 dst = dst_check(dst, inet6_sk(sk)->rx_dst_cookie);
1566                         if (dst &&
1567                             inet_sk(sk)->rx_dst_ifindex == skb->skb_iif)
1568                                 skb_dst_set_noref(skb, dst);
1569                 }
1570         }
1571 }
1572
1573 static struct timewait_sock_ops tcp6_timewait_sock_ops = {
1574         .twsk_obj_size  = sizeof(struct tcp6_timewait_sock),
1575         .twsk_unique    = tcp_twsk_unique,
1576         .twsk_destructor = tcp_twsk_destructor,
1577 };
1578
1579 static const struct inet_connection_sock_af_ops ipv6_specific = {
1580         .queue_xmit        = inet6_csk_xmit,
1581         .send_check        = tcp_v6_send_check,
1582         .rebuild_header    = inet6_sk_rebuild_header,
1583         .sk_rx_dst_set     = inet6_sk_rx_dst_set,
1584         .conn_request      = tcp_v6_conn_request,
1585         .syn_recv_sock     = tcp_v6_syn_recv_sock,
1586         .net_header_len    = sizeof(struct ipv6hdr),
1587         .net_frag_header_len = sizeof(struct frag_hdr),
1588         .setsockopt        = ipv6_setsockopt,
1589         .getsockopt        = ipv6_getsockopt,
1590         .addr2sockaddr     = inet6_csk_addr2sockaddr,
1591         .sockaddr_len      = sizeof(struct sockaddr_in6),
1592         .bind_conflict     = inet6_csk_bind_conflict,
1593 #ifdef CONFIG_COMPAT
1594         .compat_setsockopt = compat_ipv6_setsockopt,
1595         .compat_getsockopt = compat_ipv6_getsockopt,
1596 #endif
1597         .mtu_reduced       = tcp_v6_mtu_reduced,
1598 };
1599
1600 #ifdef CONFIG_TCP_MD5SIG
1601 static const struct tcp_sock_af_ops tcp_sock_ipv6_specific = {
1602         .md5_lookup     =       tcp_v6_md5_lookup,
1603         .calc_md5_hash  =       tcp_v6_md5_hash_skb,
1604         .md5_parse      =       tcp_v6_parse_md5_keys,
1605 };
1606 #endif
1607
1608 /*
1609  *      TCP over IPv4 via INET6 API
1610  */
1611 static const struct inet_connection_sock_af_ops ipv6_mapped = {
1612         .queue_xmit        = ip_queue_xmit,
1613         .send_check        = tcp_v4_send_check,
1614         .rebuild_header    = inet_sk_rebuild_header,
1615         .sk_rx_dst_set     = inet_sk_rx_dst_set,
1616         .conn_request      = tcp_v6_conn_request,
1617         .syn_recv_sock     = tcp_v6_syn_recv_sock,
1618         .net_header_len    = sizeof(struct iphdr),
1619         .setsockopt        = ipv6_setsockopt,
1620         .getsockopt        = ipv6_getsockopt,
1621         .addr2sockaddr     = inet6_csk_addr2sockaddr,
1622         .sockaddr_len      = sizeof(struct sockaddr_in6),
1623         .bind_conflict     = inet6_csk_bind_conflict,
1624 #ifdef CONFIG_COMPAT
1625         .compat_setsockopt = compat_ipv6_setsockopt,
1626         .compat_getsockopt = compat_ipv6_getsockopt,
1627 #endif
1628         .mtu_reduced       = tcp_v4_mtu_reduced,
1629 };
1630
1631 #ifdef CONFIG_TCP_MD5SIG
1632 static const struct tcp_sock_af_ops tcp_sock_ipv6_mapped_specific = {
1633         .md5_lookup     =       tcp_v4_md5_lookup,
1634         .calc_md5_hash  =       tcp_v4_md5_hash_skb,
1635         .md5_parse      =       tcp_v6_parse_md5_keys,
1636 };
1637 #endif
1638
1639 /* NOTE: A lot of things set to zero explicitly by call to
1640  *       sk_alloc() so need not be done here.
1641  */
1642 static int tcp_v6_init_sock(struct sock *sk)
1643 {
1644         struct inet_connection_sock *icsk = inet_csk(sk);
1645
1646         tcp_init_sock(sk);
1647
1648         icsk->icsk_af_ops = &ipv6_specific;
1649
1650 #ifdef CONFIG_TCP_MD5SIG
1651         tcp_sk(sk)->af_specific = &tcp_sock_ipv6_specific;
1652 #endif
1653
1654         return 0;
1655 }
1656
1657 static void tcp_v6_destroy_sock(struct sock *sk)
1658 {
1659         tcp_v4_destroy_sock(sk);
1660         inet6_destroy_sock(sk);
1661 }
1662
1663 #ifdef CONFIG_PROC_FS
1664 /* Proc filesystem TCPv6 sock list dumping. */
1665 static void get_openreq6(struct seq_file *seq,
1666                          const struct request_sock *req, int i)
1667 {
1668         long ttd = req->rsk_timer.expires - jiffies;
1669         const struct in6_addr *src = &inet_rsk(req)->ir_v6_loc_addr;
1670         const struct in6_addr *dest = &inet_rsk(req)->ir_v6_rmt_addr;
1671
1672         if (ttd < 0)
1673                 ttd = 0;
1674
1675         seq_printf(seq,
1676                    "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
1677                    "%02X %08X:%08X %02X:%08lX %08X %5u %8d %d %d %pK\n",
1678                    i,
1679                    src->s6_addr32[0], src->s6_addr32[1],
1680                    src->s6_addr32[2], src->s6_addr32[3],
1681                    inet_rsk(req)->ir_num,
1682                    dest->s6_addr32[0], dest->s6_addr32[1],
1683                    dest->s6_addr32[2], dest->s6_addr32[3],
1684                    ntohs(inet_rsk(req)->ir_rmt_port),
1685                    TCP_SYN_RECV,
1686                    0, 0, /* could print option size, but that is af dependent. */
1687                    1,   /* timers active (only the expire timer) */
1688                    jiffies_to_clock_t(ttd),
1689                    req->num_timeout,
1690                    from_kuid_munged(seq_user_ns(seq),
1691                                     sock_i_uid(req->rsk_listener)),
1692                    0,  /* non standard timer */
1693                    0, /* open_requests have no inode */
1694                    0, req);
1695 }
1696
1697 static void get_tcp6_sock(struct seq_file *seq, struct sock *sp, int i)
1698 {
1699         const struct in6_addr *dest, *src;
1700         __u16 destp, srcp;
1701         int timer_active;
1702         unsigned long timer_expires;
1703         const struct inet_sock *inet = inet_sk(sp);
1704         const struct tcp_sock *tp = tcp_sk(sp);
1705         const struct inet_connection_sock *icsk = inet_csk(sp);
1706         const struct fastopen_queue *fastopenq = &icsk->icsk_accept_queue.fastopenq;
1707         int rx_queue;
1708         int state;
1709
1710         dest  = &sp->sk_v6_daddr;
1711         src   = &sp->sk_v6_rcv_saddr;
1712         destp = ntohs(inet->inet_dport);
1713         srcp  = ntohs(inet->inet_sport);
1714
1715         if (icsk->icsk_pending == ICSK_TIME_RETRANS ||
1716             icsk->icsk_pending == ICSK_TIME_EARLY_RETRANS ||
1717             icsk->icsk_pending == ICSK_TIME_LOSS_PROBE) {
1718                 timer_active    = 1;
1719                 timer_expires   = icsk->icsk_timeout;
1720         } else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
1721                 timer_active    = 4;
1722                 timer_expires   = icsk->icsk_timeout;
1723         } else if (timer_pending(&sp->sk_timer)) {
1724                 timer_active    = 2;
1725                 timer_expires   = sp->sk_timer.expires;
1726         } else {
1727                 timer_active    = 0;
1728                 timer_expires = jiffies;
1729         }
1730
1731         state = sk_state_load(sp);
1732         if (state == TCP_LISTEN)
1733                 rx_queue = sp->sk_ack_backlog;
1734         else
1735                 /* Because we don't lock the socket,
1736                  * we might find a transient negative value.
1737                  */
1738                 rx_queue = max_t(int, tp->rcv_nxt - tp->copied_seq, 0);
1739
1740         seq_printf(seq,
1741                    "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
1742                    "%02X %08X:%08X %02X:%08lX %08X %5u %8d %lu %d %pK %lu %lu %u %u %d\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                    state,
1749                    tp->write_seq - tp->snd_una,
1750                    rx_queue,
1751                    timer_active,
1752                    jiffies_delta_to_clock_t(timer_expires - jiffies),
1753                    icsk->icsk_retransmits,
1754                    from_kuid_munged(seq_user_ns(seq), sock_i_uid(sp)),
1755                    icsk->icsk_probes_out,
1756                    sock_i_ino(sp),
1757                    atomic_read(&sp->sk_refcnt), sp,
1758                    jiffies_to_clock_t(icsk->icsk_rto),
1759                    jiffies_to_clock_t(icsk->icsk_ack.ato),
1760                    (icsk->icsk_ack.quick << 1) | icsk->icsk_ack.pingpong,
1761                    tp->snd_cwnd,
1762                    state == TCP_LISTEN ?
1763                         fastopenq->max_qlen :
1764                         (tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh)
1765                    );
1766 }
1767
1768 static void get_timewait6_sock(struct seq_file *seq,
1769                                struct inet_timewait_sock *tw, int i)
1770 {
1771         long delta = tw->tw_timer.expires - jiffies;
1772         const struct in6_addr *dest, *src;
1773         __u16 destp, srcp;
1774
1775         dest = &tw->tw_v6_daddr;
1776         src  = &tw->tw_v6_rcv_saddr;
1777         destp = ntohs(tw->tw_dport);
1778         srcp  = ntohs(tw->tw_sport);
1779
1780         seq_printf(seq,
1781                    "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
1782                    "%02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK\n",
1783                    i,
1784                    src->s6_addr32[0], src->s6_addr32[1],
1785                    src->s6_addr32[2], src->s6_addr32[3], srcp,
1786                    dest->s6_addr32[0], dest->s6_addr32[1],
1787                    dest->s6_addr32[2], dest->s6_addr32[3], destp,
1788                    tw->tw_substate, 0, 0,
1789                    3, jiffies_delta_to_clock_t(delta), 0, 0, 0, 0,
1790                    atomic_read(&tw->tw_refcnt), tw);
1791 }
1792
1793 static int tcp6_seq_show(struct seq_file *seq, void *v)
1794 {
1795         struct tcp_iter_state *st;
1796         struct sock *sk = v;
1797
1798         if (v == SEQ_START_TOKEN) {
1799                 seq_puts(seq,
1800                          "  sl  "
1801                          "local_address                         "
1802                          "remote_address                        "
1803                          "st tx_queue rx_queue tr tm->when retrnsmt"
1804                          "   uid  timeout inode\n");
1805                 goto out;
1806         }
1807         st = seq->private;
1808
1809         if (sk->sk_state == TCP_TIME_WAIT)
1810                 get_timewait6_sock(seq, v, st->num);
1811         else if (sk->sk_state == TCP_NEW_SYN_RECV)
1812                 get_openreq6(seq, v, st->num);
1813         else
1814                 get_tcp6_sock(seq, v, st->num);
1815 out:
1816         return 0;
1817 }
1818
1819 static const struct file_operations tcp6_afinfo_seq_fops = {
1820         .owner   = THIS_MODULE,
1821         .open    = tcp_seq_open,
1822         .read    = seq_read,
1823         .llseek  = seq_lseek,
1824         .release = seq_release_net
1825 };
1826
1827 static struct tcp_seq_afinfo tcp6_seq_afinfo = {
1828         .name           = "tcp6",
1829         .family         = AF_INET6,
1830         .seq_fops       = &tcp6_afinfo_seq_fops,
1831         .seq_ops        = {
1832                 .show           = tcp6_seq_show,
1833         },
1834 };
1835
1836 int __net_init tcp6_proc_init(struct net *net)
1837 {
1838         return tcp_proc_register(net, &tcp6_seq_afinfo);
1839 }
1840
1841 void tcp6_proc_exit(struct net *net)
1842 {
1843         tcp_proc_unregister(net, &tcp6_seq_afinfo);
1844 }
1845 #endif
1846
1847 static void tcp_v6_clear_sk(struct sock *sk, int size)
1848 {
1849         struct inet_sock *inet = inet_sk(sk);
1850
1851         /* we do not want to clear pinet6 field, because of RCU lookups */
1852         sk_prot_clear_nulls(sk, offsetof(struct inet_sock, pinet6));
1853
1854         size -= offsetof(struct inet_sock, pinet6) + sizeof(inet->pinet6);
1855         memset(&inet->pinet6 + 1, 0, size);
1856 }
1857
1858 struct proto tcpv6_prot = {
1859         .name                   = "TCPv6",
1860         .owner                  = THIS_MODULE,
1861         .close                  = tcp_close,
1862         .connect                = tcp_v6_connect,
1863         .disconnect             = tcp_disconnect,
1864         .accept                 = inet_csk_accept,
1865         .ioctl                  = tcp_ioctl,
1866         .init                   = tcp_v6_init_sock,
1867         .destroy                = tcp_v6_destroy_sock,
1868         .shutdown               = tcp_shutdown,
1869         .setsockopt             = tcp_setsockopt,
1870         .getsockopt             = tcp_getsockopt,
1871         .recvmsg                = tcp_recvmsg,
1872         .sendmsg                = tcp_sendmsg,
1873         .sendpage               = tcp_sendpage,
1874         .backlog_rcv            = tcp_v6_do_rcv,
1875         .release_cb             = tcp_release_cb,
1876         .hash                   = inet_hash,
1877         .unhash                 = inet_unhash,
1878         .get_port               = inet_csk_get_port,
1879         .enter_memory_pressure  = tcp_enter_memory_pressure,
1880         .stream_memory_free     = tcp_stream_memory_free,
1881         .sockets_allocated      = &tcp_sockets_allocated,
1882         .memory_allocated       = &tcp_memory_allocated,
1883         .memory_pressure        = &tcp_memory_pressure,
1884         .orphan_count           = &tcp_orphan_count,
1885         .sysctl_mem             = sysctl_tcp_mem,
1886         .sysctl_wmem            = sysctl_tcp_wmem,
1887         .sysctl_rmem            = sysctl_tcp_rmem,
1888         .max_header             = MAX_TCP_HEADER,
1889         .obj_size               = sizeof(struct tcp6_sock),
1890         .slab_flags             = SLAB_DESTROY_BY_RCU,
1891         .twsk_prot              = &tcp6_timewait_sock_ops,
1892         .rsk_prot               = &tcp6_request_sock_ops,
1893         .h.hashinfo             = &tcp_hashinfo,
1894         .no_autobind            = true,
1895 #ifdef CONFIG_COMPAT
1896         .compat_setsockopt      = compat_tcp_setsockopt,
1897         .compat_getsockopt      = compat_tcp_getsockopt,
1898 #endif
1899 #ifdef CONFIG_MEMCG_KMEM
1900         .proto_cgroup           = tcp_proto_cgroup,
1901 #endif
1902         .clear_sk               = tcp_v6_clear_sk,
1903 };
1904
1905 static const struct inet6_protocol tcpv6_protocol = {
1906         .early_demux    =       tcp_v6_early_demux,
1907         .handler        =       tcp_v6_rcv,
1908         .err_handler    =       tcp_v6_err,
1909         .flags          =       INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
1910 };
1911
1912 static struct inet_protosw tcpv6_protosw = {
1913         .type           =       SOCK_STREAM,
1914         .protocol       =       IPPROTO_TCP,
1915         .prot           =       &tcpv6_prot,
1916         .ops            =       &inet6_stream_ops,
1917         .flags          =       INET_PROTOSW_PERMANENT |
1918                                 INET_PROTOSW_ICSK,
1919 };
1920
1921 static int __net_init tcpv6_net_init(struct net *net)
1922 {
1923         return inet_ctl_sock_create(&net->ipv6.tcp_sk, PF_INET6,
1924                                     SOCK_RAW, IPPROTO_TCP, net);
1925 }
1926
1927 static void __net_exit tcpv6_net_exit(struct net *net)
1928 {
1929         inet_ctl_sock_destroy(net->ipv6.tcp_sk);
1930 }
1931
1932 static void __net_exit tcpv6_net_exit_batch(struct list_head *net_exit_list)
1933 {
1934         inet_twsk_purge(&tcp_hashinfo, &tcp_death_row, AF_INET6);
1935 }
1936
1937 static struct pernet_operations tcpv6_net_ops = {
1938         .init       = tcpv6_net_init,
1939         .exit       = tcpv6_net_exit,
1940         .exit_batch = tcpv6_net_exit_batch,
1941 };
1942
1943 int __init tcpv6_init(void)
1944 {
1945         int ret;
1946
1947         ret = inet6_add_protocol(&tcpv6_protocol, IPPROTO_TCP);
1948         if (ret)
1949                 goto out;
1950
1951         /* register inet6 protocol */
1952         ret = inet6_register_protosw(&tcpv6_protosw);
1953         if (ret)
1954                 goto out_tcpv6_protocol;
1955
1956         ret = register_pernet_subsys(&tcpv6_net_ops);
1957         if (ret)
1958                 goto out_tcpv6_protosw;
1959 out:
1960         return ret;
1961
1962 out_tcpv6_protosw:
1963         inet6_unregister_protosw(&tcpv6_protosw);
1964 out_tcpv6_protocol:
1965         inet6_del_protocol(&tcpv6_protocol, IPPROTO_TCP);
1966         goto out;
1967 }
1968
1969 void tcpv6_exit(void)
1970 {
1971         unregister_pernet_subsys(&tcpv6_net_ops);
1972         inet6_unregister_protosw(&tcpv6_protosw);
1973         inet6_del_protocol(&tcpv6_protocol, IPPROTO_TCP);
1974 }