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         fl6.flowi6_uid = sk->sk_uid;
 238
 239         opt = rcu_dereference_protected(np->opt, sock_owned_by_user(sk));
 240         final_p = fl6_update_dst(&fl6, opt, &final);
 241
 242         security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));
 243
 244         dst = ip6_dst_lookup_flow(sk, &fl6, final_p);
 245         if (IS_ERR(dst)) {
 246                 err = PTR_ERR(dst);
 247                 goto failure;
 248         }
 249
 250         if (!saddr) {
 251                 saddr = &fl6.saddr;
 252                 sk->sk_v6_rcv_saddr = *saddr;
 253         }
 254
 255         /* set the source address */
 256         np->saddr = *saddr;
 257         inet->inet_rcv_saddr = LOOPBACK4_IPV6;
 258
 259         sk->sk_gso_type = SKB_GSO_TCPV6;
 260         ip6_dst_store(sk, dst, NULL, NULL);
 261
 262         if (tcp_death_row.sysctl_tw_recycle &&
 263             !tp->rx_opt.ts_recent_stamp &&
 264             ipv6_addr_equal(&fl6.daddr, &sk->sk_v6_daddr))
 265                 tcp_fetch_timewait_stamp(sk, dst);
 266
 267         icsk->icsk_ext_hdr_len = 0;
 268         if (opt)
 269                 icsk->icsk_ext_hdr_len = opt->opt_flen +
 270                                          opt->opt_nflen;
 271
 272         tp->rx_opt.mss_clamp = IPV6_MIN_MTU - sizeof(struct tcphdr) - sizeof(struct ipv6hdr);
 273
 274         inet->inet_dport = usin->sin6_port;
 275
 276         tcp_set_state(sk, TCP_SYN_SENT);
 277         err = inet6_hash_connect(&tcp_death_row, sk);
 278         if (err)
 279                 goto late_failure;
 280
 281         sk_set_txhash(sk);
 282
 283         if (!tp->write_seq && likely(!tp->repair))
 284                 tp->write_seq = secure_tcpv6_sequence_number(np->saddr.s6_addr32,
 285                                                              sk->sk_v6_daddr.s6_addr32,
 286                                                              inet->inet_sport,
 287                                                              inet->inet_dport);
 288
 289         err = tcp_connect(sk);
 290         if (err)
 291                 goto late_failure;
 292
 293         return 0;
 294
 295 late_failure:
 296         tcp_set_state(sk, TCP_CLOSE);
 297         __sk_dst_reset(sk);
 298 failure:
 299         inet->inet_dport = 0;
 300         sk->sk_route_caps = 0;
 301         return err;
 302 }
 303
 304 static void tcp_v6_mtu_reduced(struct sock *sk)
 305 {
 306         struct dst_entry *dst;
 307
 308         if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE))
 309                 return;
 310
 311         dst = inet6_csk_update_pmtu(sk, tcp_sk(sk)->mtu_info);
 312         if (!dst)
 313                 return;
 314
 315         if (inet_csk(sk)->icsk_pmtu_cookie > dst_mtu(dst)) {
 316                 tcp_sync_mss(sk, dst_mtu(dst));
 317                 tcp_simple_retransmit(sk);
 318         }
 319 }
 320
 321 static void tcp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 322                 u8 type, u8 code, int offset, __be32 info)
 323 {
 324         const struct ipv6hdr *hdr = (const struct ipv6hdr *)skb->data;
 325         const struct tcphdr *th = (struct tcphdr *)(skb->data+offset);
 326         struct net *net = dev_net(skb->dev);
 327         struct request_sock *fastopen;
 328         struct ipv6_pinfo *np;
 329         struct tcp_sock *tp;
 330         __u32 seq, snd_una;
 331         struct sock *sk;
 332         bool fatal;
 333         int err;
 334
 335         sk = __inet6_lookup_established(net, &tcp_hashinfo,
 336                                         &hdr->daddr, th->dest,
 337                                         &hdr->saddr, ntohs(th->source),
 338                                         skb->dev->ifindex);
 339
 340         if (!sk) {
 341                 ICMP6_INC_STATS_BH(net, __in6_dev_get(skb->dev),
 342                                    ICMP6_MIB_INERRORS);
 343                 return;
 344         }
 345
 346         if (sk->sk_state == TCP_TIME_WAIT) {
 347                 inet_twsk_put(inet_twsk(sk));
 348                 return;
 349         }
 350         seq = ntohl(th->seq);
 351         fatal = icmpv6_err_convert(type, code, &err);
 352         if (sk->sk_state == TCP_NEW_SYN_RECV)
 353                 return tcp_req_err(sk, seq, fatal);
 354
 355         bh_lock_sock(sk);
 356         if (sock_owned_by_user(sk) && type != ICMPV6_PKT_TOOBIG)
 357                 NET_INC_STATS_BH(net, LINUX_MIB_LOCKDROPPEDICMPS);
 358
 359         if (sk->sk_state == TCP_CLOSE)
 360                 goto out;
 361
 362         if (ipv6_hdr(skb)->hop_limit < inet6_sk(sk)->min_hopcount) {
 363                 NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP);
 364                 goto out;
 365         }
 366
 367         tp = tcp_sk(sk);
 368         /* XXX (TFO) - tp->snd_una should be ISN (tcp_create_openreq_child() */
 369         fastopen = tp->fastopen_rsk;
 370         snd_una = fastopen ? tcp_rsk(fastopen)->snt_isn : tp->snd_una;
 371         if (sk->sk_state != TCP_LISTEN &&
 372             !between(seq, snd_una, tp->snd_nxt)) {
 373                 NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
 374                 goto out;
 375         }
 376
 377         np = inet6_sk(sk);
 378
 379         if (type == NDISC_REDIRECT) {
 380                 struct dst_entry *dst = __sk_dst_check(sk, np->dst_cookie);
 381
 382                 if (dst)
 383                         dst->ops->redirect(dst, sk, skb);
 384                 goto out;
 385         }
 386
 387         if (type == ICMPV6_PKT_TOOBIG) {
 388                 /* We are not interested in TCP_LISTEN and open_requests
 389                  * (SYN-ACKs send out by Linux are always <576bytes so
 390                  * they should go through unfragmented).
 391                  */
 392                 if (sk->sk_state == TCP_LISTEN)
 393                         goto out;
 394
 395                 if (!ip6_sk_accept_pmtu(sk))
 396                         goto out;
 397
 398                 tp->mtu_info = ntohl(info);
 399                 if (!sock_owned_by_user(sk))
 400                         tcp_v6_mtu_reduced(sk);
 401                 else if (!test_and_set_bit(TCP_MTU_REDUCED_DEFERRED,
 402                                            &tp->tsq_flags))
 403                         sock_hold(sk);
 404                 goto out;
 405         }
 406
 407
 408         /* Might be for an request_sock */
 409         switch (sk->sk_state) {
 410         case TCP_SYN_SENT:
 411         case TCP_SYN_RECV:
 412                 /* Only in fast or simultaneous open. If a fast open socket is
 413                  * is already accepted it is treated as a connected one below.
 414                  */
 415                 if (fastopen && !fastopen->sk)
 416                         break;
 417
 418                 if (!sock_owned_by_user(sk)) {
 419                         sk->sk_err = err;
 420                         sk->sk_error_report(sk);                /* Wake people up to see the error (see connect in sock.c) */
 421
 422                         tcp_done(sk);
 423                 } else
 424                         sk->sk_err_soft = err;
 425                 goto out;
 426         }
 427
 428         if (!sock_owned_by_user(sk) && np->recverr) {
 429                 sk->sk_err = err;
 430                 sk->sk_error_report(sk);
 431         } else
 432                 sk->sk_err_soft = err;
 433
 434 out:
 435         bh_unlock_sock(sk);
 436         sock_put(sk);
 437 }
 438
 439
 440 static int tcp_v6_send_synack(const struct sock *sk, struct dst_entry *dst,
 441                               struct flowi *fl,
 442                               struct request_sock *req,
 443                               struct tcp_fastopen_cookie *foc,
 444                               bool attach_req)
 445 {
 446         struct inet_request_sock *ireq = inet_rsk(req);
 447         struct ipv6_pinfo *np = inet6_sk(sk);
 448         struct flowi6 *fl6 = &fl->u.ip6;
 449         struct sk_buff *skb;
 450         int err = -ENOMEM;
 451
 452         /* First, grab a route. */
 453         if (!dst && (dst = inet6_csk_route_req(sk, fl6, req,
 454                                                IPPROTO_TCP)) == NULL)
 455                 goto done;
 456
 457         skb = tcp_make_synack(sk, dst, req, foc, attach_req);
 458
 459         if (skb) {
 460                 __tcp_v6_send_check(skb, &ireq->ir_v6_loc_addr,
 461                                     &ireq->ir_v6_rmt_addr);
 462
 463                 fl6->daddr = ireq->ir_v6_rmt_addr;
 464                 if (np->repflow && ireq->pktopts)
 465                         fl6->flowlabel = ip6_flowlabel(ipv6_hdr(ireq->pktopts));
 466
 467                 rcu_read_lock();
 468                 err = ip6_xmit(sk, skb, fl6, rcu_dereference(np->opt),
 469                                np->tclass);
 470                 rcu_read_unlock();
 471                 err = net_xmit_eval(err);
 472         }
 473
 474 done:
 475         return err;
 476 }
 477
 478
 479 static void tcp_v6_reqsk_destructor(struct request_sock *req)
 480 {
 481         kfree_skb(inet_rsk(req)->pktopts);
 482 }
 483
 484 #ifdef CONFIG_TCP_MD5SIG
 485 static struct tcp_md5sig_key *tcp_v6_md5_do_lookup(const struct sock *sk,
 486                                                    const struct in6_addr *addr)
 487 {
 488         return tcp_md5_do_lookup(sk, (union tcp_md5_addr *)addr, AF_INET6);
 489 }
 490
 491 static struct tcp_md5sig_key *tcp_v6_md5_lookup(const struct sock *sk,
 492                                                 const struct sock *addr_sk)
 493 {
 494         return tcp_v6_md5_do_lookup(sk, &addr_sk->sk_v6_daddr);
 495 }
 496
 497 static int tcp_v6_parse_md5_keys(struct sock *sk, char __user *optval,
 498                                  int optlen)
 499 {
 500         struct tcp_md5sig cmd;
 501         struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)&cmd.tcpm_addr;
 502
 503         if (optlen < sizeof(cmd))
 504                 return -EINVAL;
 505
 506         if (copy_from_user(&cmd, optval, sizeof(cmd)))
 507                 return -EFAULT;
 508
 509         if (sin6->sin6_family != AF_INET6)
 510                 return -EINVAL;
 511
 512         if (!cmd.tcpm_keylen) {
 513                 if (ipv6_addr_v4mapped(&sin6->sin6_addr))
 514                         return tcp_md5_do_del(sk, (union tcp_md5_addr *)&sin6->sin6_addr.s6_addr32[3],
 515                                               AF_INET);
 516                 return tcp_md5_do_del(sk, (union tcp_md5_addr *)&sin6->sin6_addr,
 517                                       AF_INET6);
 518         }
 519
 520         if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN)
 521                 return -EINVAL;
 522
 523         if (ipv6_addr_v4mapped(&sin6->sin6_addr))
 524                 return tcp_md5_do_add(sk, (union tcp_md5_addr *)&sin6->sin6_addr.s6_addr32[3],
 525                                       AF_INET, cmd.tcpm_key, cmd.tcpm_keylen, GFP_KERNEL);
 526
 527         return tcp_md5_do_add(sk, (union tcp_md5_addr *)&sin6->sin6_addr,
 528                               AF_INET6, cmd.tcpm_key, cmd.tcpm_keylen, GFP_KERNEL);
 529 }
 530
 531 static int tcp_v6_md5_hash_pseudoheader(struct tcp_md5sig_pool *hp,
 532                                         const struct in6_addr *daddr,
 533                                         const struct in6_addr *saddr, int nbytes)
 534 {
 535         struct tcp6_pseudohdr *bp;
 536         struct scatterlist sg;
 537
 538         bp = &hp->md5_blk.ip6;
 539         /* 1. TCP pseudo-header (RFC2460) */
 540         bp->saddr = *saddr;
 541         bp->daddr = *daddr;
 542         bp->protocol = cpu_to_be32(IPPROTO_TCP);
 543         bp->len = cpu_to_be32(nbytes);
 544
 545         sg_init_one(&sg, bp, sizeof(*bp));
 546         return crypto_hash_update(&hp->md5_desc, &sg, sizeof(*bp));
 547 }
 548
 549 static int tcp_v6_md5_hash_hdr(char *md5_hash, struct tcp_md5sig_key *key,
 550                                const struct in6_addr *daddr, struct in6_addr *saddr,
 551                                const struct tcphdr *th)
 552 {
 553         struct tcp_md5sig_pool *hp;
 554         struct hash_desc *desc;
 555
 556         hp = tcp_get_md5sig_pool();
 557         if (!hp)
 558                 goto clear_hash_noput;
 559         desc = &hp->md5_desc;
 560
 561         if (crypto_hash_init(desc))
 562                 goto clear_hash;
 563         if (tcp_v6_md5_hash_pseudoheader(hp, daddr, saddr, th->doff << 2))
 564                 goto clear_hash;
 565         if (tcp_md5_hash_header(hp, th))
 566                 goto clear_hash;
 567         if (tcp_md5_hash_key(hp, key))
 568                 goto clear_hash;
 569         if (crypto_hash_final(desc, md5_hash))
 570                 goto clear_hash;
 571
 572         tcp_put_md5sig_pool();
 573         return 0;
 574
 575 clear_hash:
 576         tcp_put_md5sig_pool();
 577 clear_hash_noput:
 578         memset(md5_hash, 0, 16);
 579         return 1;
 580 }
 581
 582 static int tcp_v6_md5_hash_skb(char *md5_hash,
 583                                const struct tcp_md5sig_key *key,
 584                                const struct sock *sk,
 585                                const struct sk_buff *skb)
 586 {
 587         const struct in6_addr *saddr, *daddr;
 588         struct tcp_md5sig_pool *hp;
 589         struct hash_desc *desc;
 590         const struct tcphdr *th = tcp_hdr(skb);
 591
 592         if (sk) { /* valid for establish/request sockets */
 593                 saddr = &sk->sk_v6_rcv_saddr;
 594                 daddr = &sk->sk_v6_daddr;
 595         } else {
 596                 const struct ipv6hdr *ip6h = ipv6_hdr(skb);
 597                 saddr = &ip6h->saddr;
 598                 daddr = &ip6h->daddr;
 599         }
 600
 601         hp = tcp_get_md5sig_pool();
 602         if (!hp)
 603                 goto clear_hash_noput;
 604         desc = &hp->md5_desc;
 605
 606         if (crypto_hash_init(desc))
 607                 goto clear_hash;
 608
 609         if (tcp_v6_md5_hash_pseudoheader(hp, daddr, saddr, skb->len))
 610                 goto clear_hash;
 611         if (tcp_md5_hash_header(hp, th))
 612                 goto clear_hash;
 613         if (tcp_md5_hash_skb_data(hp, skb, th->doff << 2))
 614                 goto clear_hash;
 615         if (tcp_md5_hash_key(hp, key))
 616                 goto clear_hash;
 617         if (crypto_hash_final(desc, md5_hash))
 618                 goto clear_hash;
 619
 620         tcp_put_md5sig_pool();
 621         return 0;
 622
 623 clear_hash:
 624         tcp_put_md5sig_pool();
 625 clear_hash_noput:
 626         memset(md5_hash, 0, 16);
 627         return 1;
 628 }
 629
 630 #endif
 631
 632 static bool tcp_v6_inbound_md5_hash(const struct sock *sk,
 633                                     const struct sk_buff *skb)
 634 {
 635 #ifdef CONFIG_TCP_MD5SIG
 636         const __u8 *hash_location = NULL;
 637         struct tcp_md5sig_key *hash_expected;
 638         const struct ipv6hdr *ip6h = ipv6_hdr(skb);
 639         const struct tcphdr *th = tcp_hdr(skb);
 640         int genhash;
 641         u8 newhash[16];
 642
 643         hash_expected = tcp_v6_md5_do_lookup(sk, &ip6h->saddr);
 644         hash_location = tcp_parse_md5sig_option(th);
 645
 646         /* We've parsed the options - do we have a hash? */
 647         if (!hash_expected && !hash_location)
 648                 return false;
 649
 650         if (hash_expected && !hash_location) {
 651                 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5NOTFOUND);
 652                 return true;
 653         }
 654
 655         if (!hash_expected && hash_location) {
 656                 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5UNEXPECTED);
 657                 return true;
 658         }
 659
 660         /* check the signature */
 661         genhash = tcp_v6_md5_hash_skb(newhash,
 662                                       hash_expected,
 663                                       NULL, skb);
 664
 665         if (genhash || memcmp(hash_location, newhash, 16) != 0) {
 666                 net_info_ratelimited("MD5 Hash %s for [%pI6c]:%u->[%pI6c]:%u\n",
 667                                      genhash ? "failed" : "mismatch",
 668                                      &ip6h->saddr, ntohs(th->source),
 669                                      &ip6h->daddr, ntohs(th->dest));
 670                 return true;
 671         }
 672 #endif
 673         return false;
 674 }
 675
 676 static void tcp_v6_init_req(struct request_sock *req,
 677                             const struct sock *sk_listener,
 678                             struct sk_buff *skb)
 679 {
 680         struct inet_request_sock *ireq = inet_rsk(req);
 681         const struct ipv6_pinfo *np = inet6_sk(sk_listener);
 682
 683         ireq->ir_v6_rmt_addr = ipv6_hdr(skb)->saddr;
 684         ireq->ir_v6_loc_addr = ipv6_hdr(skb)->daddr;
 685
 686         /* So that link locals have meaning */
 687         if (!sk_listener->sk_bound_dev_if &&
 688             ipv6_addr_type(&ireq->ir_v6_rmt_addr) & IPV6_ADDR_LINKLOCAL)
 689                 ireq->ir_iif = tcp_v6_iif(skb);
 690
 691         if (!TCP_SKB_CB(skb)->tcp_tw_isn &&
 692             (ipv6_opt_accepted(sk_listener, skb, &TCP_SKB_CB(skb)->header.h6) ||
 693              np->rxopt.bits.rxinfo ||
 694              np->rxopt.bits.rxoinfo || np->rxopt.bits.rxhlim ||
 695              np->rxopt.bits.rxohlim || np->repflow)) {
 696                 atomic_inc(&skb->users);
 697                 ireq->pktopts = skb;
 698         }
 699 }
 700
 701 static struct dst_entry *tcp_v6_route_req(const struct sock *sk,
 702                                           struct flowi *fl,
 703                                           const struct request_sock *req,
 704                                           bool *strict)
 705 {
 706         if (strict)
 707                 *strict = true;
 708         return inet6_csk_route_req(sk, &fl->u.ip6, req, IPPROTO_TCP);
 709 }
 710
 711 struct request_sock_ops tcp6_request_sock_ops __read_mostly = {
 712         .family         =       AF_INET6,
 713         .obj_size       =       sizeof(struct tcp6_request_sock),
 714         .rtx_syn_ack    =       tcp_rtx_synack,
 715         .send_ack       =       tcp_v6_reqsk_send_ack,
 716         .destructor     =       tcp_v6_reqsk_destructor,
 717         .send_reset     =       tcp_v6_send_reset,
 718         .syn_ack_timeout =      tcp_syn_ack_timeout,
 719 };
 720
 721 static const struct tcp_request_sock_ops tcp_request_sock_ipv6_ops = {
 722         .mss_clamp      =       IPV6_MIN_MTU - sizeof(struct tcphdr) -
 723                                 sizeof(struct ipv6hdr),
 724 #ifdef CONFIG_TCP_MD5SIG
 725         .req_md5_lookup =       tcp_v6_md5_lookup,
 726         .calc_md5_hash  =       tcp_v6_md5_hash_skb,
 727 #endif
 728         .init_req       =       tcp_v6_init_req,
 729 #ifdef CONFIG_SYN_COOKIES
 730         .cookie_init_seq =      cookie_v6_init_sequence,
 731 #endif
 732         .route_req      =       tcp_v6_route_req,
 733         .init_seq       =       tcp_v6_init_sequence,
 734         .send_synack    =       tcp_v6_send_synack,
 735 };
 736
 737 static void tcp_v6_send_response(const struct sock *sk, struct sk_buff *skb, u32 seq,
 738                                  u32 ack, u32 win, u32 tsval, u32 tsecr,
 739                                  int oif, struct tcp_md5sig_key *key, int rst,
 740                                  u8 tclass, u32 label)
 741 {
 742         const struct tcphdr *th = tcp_hdr(skb);
 743         struct tcphdr *t1;
 744         struct sk_buff *buff;
 745         struct flowi6 fl6;
 746         struct net *net = sk ? sock_net(sk) : dev_net(skb_dst(skb)->dev);
 747         struct sock *ctl_sk = net->ipv6.tcp_sk;
 748         unsigned int tot_len = sizeof(struct tcphdr);
 749         struct dst_entry *dst;
 750         __be32 *topt;
 751
 752         if (tsecr)
 753                 tot_len += TCPOLEN_TSTAMP_ALIGNED;
 754 #ifdef CONFIG_TCP_MD5SIG
 755         if (key)
 756                 tot_len += TCPOLEN_MD5SIG_ALIGNED;
 757 #endif
 758
 759         buff = alloc_skb(MAX_HEADER + sizeof(struct ipv6hdr) + tot_len,
 760                          GFP_ATOMIC);
 761         if (!buff)
 762                 return;
 763
 764         skb_reserve(buff, MAX_HEADER + sizeof(struct ipv6hdr) + tot_len);
 765
 766         t1 = (struct tcphdr *) skb_push(buff, tot_len);
 767         skb_reset_transport_header(buff);
 768
 769         /* Swap the send and the receive. */
 770         memset(t1, 0, sizeof(*t1));
 771         t1->dest = th->source;
 772         t1->source = th->dest;
 773         t1->doff = tot_len / 4;
 774         t1->seq = htonl(seq);
 775         t1->ack_seq = htonl(ack);
 776         t1->ack = !rst || !th->ack;
 777         t1->rst = rst;
 778         t1->window = htons(win);
 779
 780         topt = (__be32 *)(t1 + 1);
 781
 782         if (tsecr) {
 783                 *topt++ = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
 784                                 (TCPOPT_TIMESTAMP << 8) | TCPOLEN_TIMESTAMP);
 785                 *topt++ = htonl(tsval);
 786                 *topt++ = htonl(tsecr);
 787         }
 788
 789 #ifdef CONFIG_TCP_MD5SIG
 790         if (key) {
 791                 *topt++ = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
 792                                 (TCPOPT_MD5SIG << 8) | TCPOLEN_MD5SIG);
 793                 tcp_v6_md5_hash_hdr((__u8 *)topt, key,
 794                                     &ipv6_hdr(skb)->saddr,
 795                                     &ipv6_hdr(skb)->daddr, t1);
 796         }
 797 #endif
 798
 799         memset(&fl6, 0, sizeof(fl6));
 800         fl6.daddr = ipv6_hdr(skb)->saddr;
 801         fl6.saddr = ipv6_hdr(skb)->daddr;
 802         fl6.flowlabel = label;
 803
 804         buff->ip_summed = CHECKSUM_PARTIAL;
 805         buff->csum = 0;
 806
 807         __tcp_v6_send_check(buff, &fl6.saddr, &fl6.daddr);
 808
 809         fl6.flowi6_proto = IPPROTO_TCP;
 810         if (rt6_need_strict(&fl6.daddr) && !oif)
 811                 fl6.flowi6_oif = tcp_v6_iif(skb);
 812         else
 813                 fl6.flowi6_oif = oif;
 814         fl6.flowi6_mark = IP6_REPLY_MARK(net, skb->mark);
 815         fl6.fl6_dport = t1->dest;
 816         fl6.fl6_sport = t1->source;
 817         fl6.flowi6_uid = sock_net_uid(net, sk && sk_fullsock(sk) ? sk : NULL);
 818         security_skb_classify_flow(skb, flowi6_to_flowi(&fl6));
 819
 820         /* Pass a socket to ip6_dst_lookup either it is for RST
 821          * Underlying function will use this to retrieve the network
 822          * namespace
 823          */
 824         dst = ip6_dst_lookup_flow(ctl_sk, &fl6, NULL);
 825         if (!IS_ERR(dst)) {
 826                 skb_dst_set(buff, dst);
 827                 ip6_xmit(ctl_sk, buff, &fl6, NULL, tclass);
 828                 TCP_INC_STATS_BH(net, TCP_MIB_OUTSEGS);
 829                 if (rst)
 830                         TCP_INC_STATS_BH(net, TCP_MIB_OUTRSTS);
 831                 return;
 832         }
 833
 834         kfree_skb(buff);
 835 }
 836
 837 static void tcp_v6_send_reset(const struct sock *sk, struct sk_buff *skb)
 838 {
 839         const struct tcphdr *th = tcp_hdr(skb);
 840         u32 seq = 0, ack_seq = 0;
 841         struct tcp_md5sig_key *key = NULL;
 842 #ifdef CONFIG_TCP_MD5SIG
 843         const __u8 *hash_location = NULL;
 844         struct ipv6hdr *ipv6h = ipv6_hdr(skb);
 845         unsigned char newhash[16];
 846         int genhash;
 847         struct sock *sk1 = NULL;
 848 #endif
 849         int oif;
 850
 851         if (th->rst)
 852                 return;
 853
 854         /* If sk not NULL, it means we did a successful lookup and incoming
 855          * route had to be correct. prequeue might have dropped our dst.
 856          */
 857         if (!sk && !ipv6_unicast_destination(skb))
 858                 return;
 859
 860 #ifdef CONFIG_TCP_MD5SIG
 861         hash_location = tcp_parse_md5sig_option(th);
 862         if (!sk && hash_location) {
 863                 /*
 864                  * active side is lost. Try to find listening socket through
 865                  * source port, and then find md5 key through listening socket.
 866                  * we are not loose security here:
 867                  * Incoming packet is checked with md5 hash with finding key,
 868                  * no RST generated if md5 hash doesn't match.
 869                  */
 870                 sk1 = inet6_lookup_listener(dev_net(skb_dst(skb)->dev),
 871                                            &tcp_hashinfo, &ipv6h->saddr,
 872                                            th->source, &ipv6h->daddr,
 873                                            ntohs(th->source), tcp_v6_iif(skb));
 874                 if (!sk1)
 875                         return;
 876
 877                 rcu_read_lock();
 878                 key = tcp_v6_md5_do_lookup(sk1, &ipv6h->saddr);
 879                 if (!key)
 880                         goto release_sk1;
 881
 882                 genhash = tcp_v6_md5_hash_skb(newhash, key, NULL, skb);
 883                 if (genhash || memcmp(hash_location, newhash, 16) != 0)
 884                         goto release_sk1;
 885         } else {
 886                 key = sk ? tcp_v6_md5_do_lookup(sk, &ipv6h->saddr) : NULL;
 887         }
 888 #endif
 889
 890         if (th->ack)
 891                 seq = ntohl(th->ack_seq);
 892         else
 893                 ack_seq = ntohl(th->seq) + th->syn + th->fin + skb->len -
 894                           (th->doff << 2);
 895
 896         oif = sk ? sk->sk_bound_dev_if : 0;
 897         tcp_v6_send_response(sk, skb, seq, ack_seq, 0, 0, 0, oif, key, 1, 0, 0);
 898
 899 #ifdef CONFIG_TCP_MD5SIG
 900 release_sk1:
 901         if (sk1) {
 902                 rcu_read_unlock();
 903                 sock_put(sk1);
 904         }
 905 #endif
 906 }
 907
 908 static void tcp_v6_send_ack(const struct sock *sk, struct sk_buff *skb, u32 seq,
 909                             u32 ack, u32 win, u32 tsval, u32 tsecr, int oif,
 910                             struct tcp_md5sig_key *key, u8 tclass,
 911                             u32 label)
 912 {
 913         tcp_v6_send_response(sk, skb, seq, ack, win, tsval, tsecr, oif, key, 0,
 914                              tclass, label);
 915 }
 916
 917 static void tcp_v6_timewait_ack(struct sock *sk, struct sk_buff *skb)
 918 {
 919         struct inet_timewait_sock *tw = inet_twsk(sk);
 920         struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
 921
 922         tcp_v6_send_ack(sk, skb, tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
 923                         tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
 924                         tcp_time_stamp + tcptw->tw_ts_offset,
 925                         tcptw->tw_ts_recent, tw->tw_bound_dev_if, tcp_twsk_md5_key(tcptw),
 926                         tw->tw_tclass, cpu_to_be32(tw->tw_flowlabel));
 927
 928         inet_twsk_put(tw);
 929 }
 930
 931 static void tcp_v6_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb,
 932                                   struct request_sock *req)
 933 {
 934         /* sk->sk_state == TCP_LISTEN -> for regular TCP_SYN_RECV
 935          * sk->sk_state == TCP_SYN_RECV -> for Fast Open.
 936          */
 937         /* RFC 7323 2.3
 938          * The window field (SEG.WND) of every outgoing segment, with the
 939          * exception of <SYN> segments, MUST be right-shifted by
 940          * Rcv.Wind.Shift bits:
 941          */
 942         tcp_v6_send_ack(sk, skb, (sk->sk_state == TCP_LISTEN) ?
 943                         tcp_rsk(req)->snt_isn + 1 : tcp_sk(sk)->snd_nxt,
 944                         tcp_rsk(req)->rcv_nxt,
 945                         req->rsk_rcv_wnd >> inet_rsk(req)->rcv_wscale,
 946                         tcp_time_stamp, req->ts_recent, sk->sk_bound_dev_if,
 947                         tcp_v6_md5_do_lookup(sk, &ipv6_hdr(skb)->daddr),
 948                         0, 0);
 949 }
 950
 951
 952 static struct sock *tcp_v6_cookie_check(struct sock *sk, struct sk_buff *skb)
 953 {
 954 #ifdef CONFIG_SYN_COOKIES
 955         const struct tcphdr *th = tcp_hdr(skb);
 956
 957         if (!th->syn)
 958                 sk = cookie_v6_check(sk, skb);
 959 #endif
 960         return sk;
 961 }
 962
 963 static int tcp_v6_conn_request(struct sock *sk, struct sk_buff *skb)
 964 {
 965         if (skb->protocol == htons(ETH_P_IP))
 966                 return tcp_v4_conn_request(sk, skb);
 967
 968         if (!ipv6_unicast_destination(skb))
 969                 goto drop;
 970
 971         return tcp_conn_request(&tcp6_request_sock_ops,
 972                                 &tcp_request_sock_ipv6_ops, sk, skb);
 973
 974 drop:
 975         NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
 976         return 0; /* don't send reset */
 977 }
 978
 979 static struct sock *tcp_v6_syn_recv_sock(const struct sock *sk, struct sk_buff *skb,
 980                                          struct request_sock *req,
 981                                          struct dst_entry *dst,
 982                                          struct request_sock *req_unhash,
 983                                          bool *own_req)
 984 {
 985         struct inet_request_sock *ireq;
 986         struct ipv6_pinfo *newnp;
 987         const struct ipv6_pinfo *np = inet6_sk(sk);
 988         struct ipv6_txoptions *opt;
 989         struct tcp6_sock *newtcp6sk;
 990         struct inet_sock *newinet;
 991         struct tcp_sock *newtp;
 992         struct sock *newsk;
 993 #ifdef CONFIG_TCP_MD5SIG
 994         struct tcp_md5sig_key *key;
 995 #endif
 996         struct flowi6 fl6;
 997
 998         if (skb->protocol == htons(ETH_P_IP)) {
 999                 /*
1000                  *      v6 mapped
1001                  */
1002
1003                 newsk = tcp_v4_syn_recv_sock(sk, skb, req, dst,
1004                                              req_unhash, own_req);
1005
1006                 if (!newsk)
1007                         return NULL;
1008
1009                 newtcp6sk = (struct tcp6_sock *)newsk;
1010                 inet_sk(newsk)->pinet6 = &newtcp6sk->inet6;
1011
1012                 newinet = inet_sk(newsk);
1013                 newnp = inet6_sk(newsk);
1014                 newtp = tcp_sk(newsk);
1015
1016                 memcpy(newnp, np, sizeof(struct ipv6_pinfo));
1017
1018                 newnp->saddr = newsk->sk_v6_rcv_saddr;
1019
1020                 inet_csk(newsk)->icsk_af_ops = &ipv6_mapped;
1021                 newsk->sk_backlog_rcv = tcp_v4_do_rcv;
1022 #ifdef CONFIG_TCP_MD5SIG
1023                 newtp->af_specific = &tcp_sock_ipv6_mapped_specific;
1024 #endif
1025
1026                 newnp->ipv6_ac_list = NULL;
1027                 newnp->ipv6_fl_list = NULL;
1028                 newnp->pktoptions  = NULL;
1029                 newnp->opt         = NULL;
1030                 newnp->mcast_oif   = tcp_v6_iif(skb);
1031                 newnp->mcast_hops  = ipv6_hdr(skb)->hop_limit;
1032                 newnp->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(skb));
1033                 if (np->repflow)
1034                         newnp->flow_label = ip6_flowlabel(ipv6_hdr(skb));
1035
1036                 /*
1037                  * No need to charge this sock to the relevant IPv6 refcnt debug socks count
1038                  * here, tcp_create_openreq_child now does this for us, see the comment in
1039                  * that function for the gory details. -acme
1040                  */
1041
1042                 /* It is tricky place. Until this moment IPv4 tcp
1043                    worked with IPv6 icsk.icsk_af_ops.
1044                    Sync it now.
1045                  */
1046                 tcp_sync_mss(newsk, inet_csk(newsk)->icsk_pmtu_cookie);
1047
1048                 return newsk;
1049         }
1050
1051         ireq = inet_rsk(req);
1052
1053         if (sk_acceptq_is_full(sk))
1054                 goto out_overflow;
1055
1056         if (!dst) {
1057                 dst = inet6_csk_route_req(sk, &fl6, req, IPPROTO_TCP);
1058                 if (!dst)
1059                         goto out;
1060         }
1061
1062         newsk = tcp_create_openreq_child(sk, req, skb);
1063         if (!newsk)
1064                 goto out_nonewsk;
1065
1066         /*
1067          * No need to charge this sock to the relevant IPv6 refcnt debug socks
1068          * count here, tcp_create_openreq_child now does this for us, see the
1069          * comment in that function for the gory details. -acme
1070          */
1071
1072         newsk->sk_gso_type = SKB_GSO_TCPV6;
1073         ip6_dst_store(newsk, dst, NULL, NULL);
1074         inet6_sk_rx_dst_set(newsk, skb);
1075
1076         newtcp6sk = (struct tcp6_sock *)newsk;
1077         inet_sk(newsk)->pinet6 = &newtcp6sk->inet6;
1078
1079         newtp = tcp_sk(newsk);
1080         newinet = inet_sk(newsk);
1081         newnp = inet6_sk(newsk);
1082
1083         memcpy(newnp, np, sizeof(struct ipv6_pinfo));
1084
1085         newsk->sk_v6_daddr = ireq->ir_v6_rmt_addr;
1086         newnp->saddr = ireq->ir_v6_loc_addr;
1087         newsk->sk_v6_rcv_saddr = ireq->ir_v6_loc_addr;
1088         newsk->sk_bound_dev_if = ireq->ir_iif;
1089
1090         /* Now IPv6 options...
1091
1092            First: no IPv4 options.
1093          */
1094         newinet->inet_opt = NULL;
1095         newnp->ipv6_ac_list = NULL;
1096         newnp->ipv6_fl_list = NULL;
1097
1098         /* Clone RX bits */
1099         newnp->rxopt.all = np->rxopt.all;
1100
1101         newnp->pktoptions = NULL;
1102         newnp->opt        = NULL;
1103         newnp->mcast_oif  = tcp_v6_iif(skb);
1104         newnp->mcast_hops = ipv6_hdr(skb)->hop_limit;
1105         newnp->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(skb));
1106         if (np->repflow)
1107                 newnp->flow_label = ip6_flowlabel(ipv6_hdr(skb));
1108
1109         /* Clone native IPv6 options from listening socket (if any)
1110
1111            Yes, keeping reference count would be much more clever,
1112            but we make one more one thing there: reattach optmem
1113            to newsk.
1114          */
1115         opt = rcu_dereference(np->opt);
1116         if (opt) {
1117                 opt = ipv6_dup_options(newsk, opt);
1118                 RCU_INIT_POINTER(newnp->opt, opt);
1119         }
1120         inet_csk(newsk)->icsk_ext_hdr_len = 0;
1121         if (opt)
1122                 inet_csk(newsk)->icsk_ext_hdr_len = opt->opt_nflen +
1123                                                     opt->opt_flen;
1124
1125         tcp_ca_openreq_child(newsk, dst);
1126
1127         tcp_sync_mss(newsk, dst_mtu(dst));
1128         newtp->advmss = dst_metric_advmss(dst);
1129         if (tcp_sk(sk)->rx_opt.user_mss &&
1130             tcp_sk(sk)->rx_opt.user_mss < newtp->advmss)
1131                 newtp->advmss = tcp_sk(sk)->rx_opt.user_mss;
1132
1133         tcp_initialize_rcv_mss(newsk);
1134
1135         newinet->inet_daddr = newinet->inet_saddr = LOOPBACK4_IPV6;
1136         newinet->inet_rcv_saddr = LOOPBACK4_IPV6;
1137
1138 #ifdef CONFIG_TCP_MD5SIG
1139         /* Copy over the MD5 key from the original socket */
1140         key = tcp_v6_md5_do_lookup(sk, &newsk->sk_v6_daddr);
1141         if (key) {
1142                 /* We're using one, so create a matching key
1143                  * on the newsk structure. If we fail to get
1144                  * memory, then we end up not copying the key
1145                  * across. Shucks.
1146                  */
1147                 tcp_md5_do_add(newsk, (union tcp_md5_addr *)&newsk->sk_v6_daddr,
1148                                AF_INET6, key->key, key->keylen,
1149                                sk_gfp_atomic(sk, GFP_ATOMIC));
1150         }
1151 #endif
1152
1153         if (__inet_inherit_port(sk, newsk) < 0) {
1154                 inet_csk_prepare_forced_close(newsk);
1155                 tcp_done(newsk);
1156                 goto out;
1157         }
1158         *own_req = inet_ehash_nolisten(newsk, req_to_sk(req_unhash));
1159         if (*own_req) {
1160                 tcp_move_syn(newtp, req);
1161
1162                 /* Clone pktoptions received with SYN, if we own the req */
1163                 if (ireq->pktopts) {
1164                         newnp->pktoptions = skb_clone(ireq->pktopts,
1165                                                       sk_gfp_atomic(sk, GFP_ATOMIC));
1166                         consume_skb(ireq->pktopts);
1167                         ireq->pktopts = NULL;
1168                         if (newnp->pktoptions)
1169                                 skb_set_owner_r(newnp->pktoptions, newsk);
1170                 }
1171         }
1172
1173         return newsk;
1174
1175 out_overflow:
1176         NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
1177 out_nonewsk:
1178         dst_release(dst);
1179 out:
1180         NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
1181         return NULL;
1182 }
1183
1184 static void tcp_v6_restore_cb(struct sk_buff *skb)
1185 {
1186         /* We need to move header back to the beginning if xfrm6_policy_check()
1187          * and tcp_v6_fill_cb() are going to be called again.
1188          * ip6_datagram_recv_specific_ctl() also expects IP6CB to be there.
1189          */
1190         memmove(IP6CB(skb), &TCP_SKB_CB(skb)->header.h6,
1191                 sizeof(struct inet6_skb_parm));
1192 }
1193
1194 /* The socket must have it's spinlock held when we get
1195  * here, unless it is a TCP_LISTEN socket.
1196  *
1197  * We have a potential double-lock case here, so even when
1198  * doing backlog processing we use the BH locking scheme.
1199  * This is because we cannot sleep with the original spinlock
1200  * held.
1201  */
1202 static int tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb)
1203 {
1204         struct ipv6_pinfo *np = inet6_sk(sk);
1205         struct tcp_sock *tp;
1206         struct sk_buff *opt_skb = NULL;
1207
1208         /* Imagine: socket is IPv6. IPv4 packet arrives,
1209            goes to IPv4 receive handler and backlogged.
1210            From backlog it always goes here. Kerboom...
1211            Fortunately, tcp_rcv_established and rcv_established
1212            handle them correctly, but it is not case with
1213            tcp_v6_hnd_req and tcp_v6_send_reset().   --ANK
1214          */
1215
1216         if (skb->protocol == htons(ETH_P_IP))
1217                 return tcp_v4_do_rcv(sk, skb);
1218
1219         if (tcp_filter(sk, skb))
1220                 goto discard;
1221
1222         /*
1223          *      socket locking is here for SMP purposes as backlog rcv
1224          *      is currently called with bh processing disabled.
1225          */
1226
1227         /* Do Stevens' IPV6_PKTOPTIONS.
1228
1229            Yes, guys, it is the only place in our code, where we
1230            may make it not affecting IPv4.
1231            The rest of code is protocol independent,
1232            and I do not like idea to uglify IPv4.
1233
1234            Actually, all the idea behind IPV6_PKTOPTIONS
1235            looks not very well thought. For now we latch
1236            options, received in the last packet, enqueued
1237            by tcp. Feel free to propose better solution.
1238                                                --ANK (980728)
1239          */
1240         if (np->rxopt.all)
1241                 opt_skb = skb_clone(skb, sk_gfp_atomic(sk, GFP_ATOMIC));
1242
1243         if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
1244                 struct dst_entry *dst = sk->sk_rx_dst;
1245
1246                 sock_rps_save_rxhash(sk, skb);
1247                 sk_mark_napi_id(sk, skb);
1248                 if (dst) {
1249                         if (inet_sk(sk)->rx_dst_ifindex != skb->skb_iif ||
1250                             dst->ops->check(dst, np->rx_dst_cookie) == NULL) {
1251                                 dst_release(dst);
1252                                 sk->sk_rx_dst = NULL;
1253                         }
1254                 }
1255
1256                 tcp_rcv_established(sk, skb, tcp_hdr(skb), skb->len);
1257                 if (opt_skb)
1258                         goto ipv6_pktoptions;
1259                 return 0;
1260         }
1261
1262         if (tcp_checksum_complete(skb))
1263                 goto csum_err;
1264
1265         if (sk->sk_state == TCP_LISTEN) {
1266                 struct sock *nsk = tcp_v6_cookie_check(sk, skb);
1267
1268                 if (!nsk)
1269                         goto discard;
1270
1271                 if (nsk != sk) {
1272                         sock_rps_save_rxhash(nsk, skb);
1273                         sk_mark_napi_id(nsk, skb);
1274                         if (tcp_child_process(sk, nsk, skb))
1275                                 goto reset;
1276                         if (opt_skb)
1277                                 __kfree_skb(opt_skb);
1278                         return 0;
1279                 }
1280         } else
1281                 sock_rps_save_rxhash(sk, skb);
1282
1283         if (tcp_rcv_state_process(sk, skb))
1284                 goto reset;
1285         if (opt_skb)
1286                 goto ipv6_pktoptions;
1287         return 0;
1288
1289 reset:
1290         tcp_v6_send_reset(sk, skb);
1291 discard:
1292         if (opt_skb)
1293                 __kfree_skb(opt_skb);
1294         kfree_skb(skb);
1295         return 0;
1296 csum_err:
1297         TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_CSUMERRORS);
1298         TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_INERRS);
1299         goto discard;
1300
1301
1302 ipv6_pktoptions:
1303         /* Do you ask, what is it?
1304
1305            1. skb was enqueued by tcp.
1306            2. skb is added to tail of read queue, rather than out of order.
1307            3. socket is not in passive state.
1308            4. Finally, it really contains options, which user wants to receive.
1309          */
1310         tp = tcp_sk(sk);
1311         if (TCP_SKB_CB(opt_skb)->end_seq == tp->rcv_nxt &&
1312             !((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN))) {
1313                 if (np->rxopt.bits.rxinfo || np->rxopt.bits.rxoinfo)
1314                         np->mcast_oif = tcp_v6_iif(opt_skb);
1315                 if (np->rxopt.bits.rxhlim || np->rxopt.bits.rxohlim)
1316                         np->mcast_hops = ipv6_hdr(opt_skb)->hop_limit;
1317                 if (np->rxopt.bits.rxflow || np->rxopt.bits.rxtclass)
1318                         np->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(opt_skb));
1319                 if (np->repflow)
1320                         np->flow_label = ip6_flowlabel(ipv6_hdr(opt_skb));
1321                 if (ipv6_opt_accepted(sk, opt_skb, &TCP_SKB_CB(opt_skb)->header.h6)) {
1322                         skb_set_owner_r(opt_skb, sk);
1323                         tcp_v6_restore_cb(opt_skb);
1324                         opt_skb = xchg(&np->pktoptions, opt_skb);
1325                 } else {
1326                         __kfree_skb(opt_skb);
1327                         opt_skb = xchg(&np->pktoptions, NULL);
1328                 }
1329         }
1330
1331         kfree_skb(opt_skb);
1332         return 0;
1333 }
1334
1335 static void tcp_v6_fill_cb(struct sk_buff *skb, const struct ipv6hdr *hdr,
1336                            const struct tcphdr *th)
1337 {
1338         /* This is tricky: we move IP6CB at its correct location into
1339          * TCP_SKB_CB(). It must be done after xfrm6_policy_check(), because
1340          * _decode_session6() uses IP6CB().
1341          * barrier() makes sure compiler won't play aliasing games.
1342          */
1343         memmove(&TCP_SKB_CB(skb)->header.h6, IP6CB(skb),
1344                 sizeof(struct inet6_skb_parm));
1345         barrier();
1346
1347         TCP_SKB_CB(skb)->seq = ntohl(th->seq);
1348         TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
1349                                     skb->len - th->doff*4);
1350         TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
1351         TCP_SKB_CB(skb)->tcp_flags = tcp_flag_byte(th);
1352         TCP_SKB_CB(skb)->tcp_tw_isn = 0;
1353         TCP_SKB_CB(skb)->ip_dsfield = ipv6_get_dsfield(hdr);
1354         TCP_SKB_CB(skb)->sacked = 0;
1355 }
1356
1357 static int tcp_v6_rcv(struct sk_buff *skb)
1358 {
1359         const struct tcphdr *th;
1360         const struct ipv6hdr *hdr;
1361         struct sock *sk;
1362         int ret;
1363         struct net *net = dev_net(skb->dev);
1364
1365         if (skb->pkt_type != PACKET_HOST)
1366                 goto discard_it;
1367
1368         /*
1369          *      Count it even if it's bad.
1370          */
1371         TCP_INC_STATS_BH(net, TCP_MIB_INSEGS);
1372
1373         if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
1374                 goto discard_it;
1375
1376         th = tcp_hdr(skb);
1377
1378         if (th->doff < sizeof(struct tcphdr)/4)
1379                 goto bad_packet;
1380         if (!pskb_may_pull(skb, th->doff*4))
1381                 goto discard_it;
1382
1383         if (skb_checksum_init(skb, IPPROTO_TCP, ip6_compute_pseudo))
1384                 goto csum_error;
1385
1386         th = tcp_hdr(skb);
1387         hdr = ipv6_hdr(skb);
1388
1389 lookup:
1390         sk = __inet6_lookup_skb(&tcp_hashinfo, skb, th->source, th->dest,
1391                                 inet6_iif(skb));
1392         if (!sk)
1393                 goto no_tcp_socket;
1394
1395 process:
1396         if (sk->sk_state == TCP_TIME_WAIT)
1397                 goto do_time_wait;
1398
1399         if (sk->sk_state == TCP_NEW_SYN_RECV) {
1400                 struct request_sock *req = inet_reqsk(sk);
1401                 struct sock *nsk;
1402
1403                 sk = req->rsk_listener;
1404                 tcp_v6_fill_cb(skb, hdr, th);
1405                 if (tcp_v6_inbound_md5_hash(sk, skb)) {
1406                         reqsk_put(req);
1407                         goto discard_it;
1408                 }
1409                 if (unlikely(sk->sk_state != TCP_LISTEN)) {
1410                         inet_csk_reqsk_queue_drop_and_put(sk, req);
1411                         goto lookup;
1412                 }
1413                 sock_hold(sk);
1414                 nsk = tcp_check_req(sk, skb, req, false);
1415                 if (!nsk) {
1416                         reqsk_put(req);
1417                         goto discard_and_relse;
1418                 }
1419                 if (nsk == sk) {
1420                         reqsk_put(req);
1421                         tcp_v6_restore_cb(skb);
1422                 } else if (tcp_child_process(sk, nsk, skb)) {
1423                         tcp_v6_send_reset(nsk, skb);
1424                         goto discard_and_relse;
1425                 } else {
1426                         sock_put(sk);
1427                         return 0;
1428                 }
1429         }
1430         if (hdr->hop_limit < inet6_sk(sk)->min_hopcount) {
1431                 NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP);
1432                 goto discard_and_relse;
1433         }
1434
1435         if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb))
1436                 goto discard_and_relse;
1437
1438         tcp_v6_fill_cb(skb, hdr, th);
1439
1440         if (tcp_v6_inbound_md5_hash(sk, skb))
1441                 goto discard_and_relse;
1442
1443         if (tcp_filter(sk, skb))
1444                 goto discard_and_relse;
1445         th = (const struct tcphdr *)skb->data;
1446         hdr = ipv6_hdr(skb);
1447
1448         skb->dev = NULL;
1449
1450         if (sk->sk_state == TCP_LISTEN) {
1451                 ret = tcp_v6_do_rcv(sk, skb);
1452                 goto put_and_return;
1453         }
1454
1455         sk_incoming_cpu_update(sk);
1456
1457         bh_lock_sock_nested(sk);
1458         tcp_sk(sk)->segs_in += max_t(u16, 1, skb_shinfo(skb)->gso_segs);
1459         ret = 0;
1460         if (!sock_owned_by_user(sk)) {
1461                 if (!tcp_prequeue(sk, skb))
1462                         ret = tcp_v6_do_rcv(sk, skb);
1463         } else if (unlikely(sk_add_backlog(sk, skb,
1464                                            sk->sk_rcvbuf + sk->sk_sndbuf))) {
1465                 bh_unlock_sock(sk);
1466                 NET_INC_STATS_BH(net, LINUX_MIB_TCPBACKLOGDROP);
1467                 goto discard_and_relse;
1468         }
1469         bh_unlock_sock(sk);
1470
1471 put_and_return:
1472         sock_put(sk);
1473         return ret ? -1 : 0;
1474
1475 no_tcp_socket:
1476         if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb))
1477                 goto discard_it;
1478
1479         tcp_v6_fill_cb(skb, hdr, th);
1480
1481         if (tcp_checksum_complete(skb)) {
1482 csum_error:
1483                 TCP_INC_STATS_BH(net, TCP_MIB_CSUMERRORS);
1484 bad_packet:
1485                 TCP_INC_STATS_BH(net, TCP_MIB_INERRS);
1486         } else {
1487                 tcp_v6_send_reset(NULL, skb);
1488         }
1489
1490 discard_it:
1491         kfree_skb(skb);
1492         return 0;
1493
1494 discard_and_relse:
1495         sock_put(sk);
1496         goto discard_it;
1497
1498 do_time_wait:
1499         if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
1500                 inet_twsk_put(inet_twsk(sk));
1501                 goto discard_it;
1502         }
1503
1504         tcp_v6_fill_cb(skb, hdr, th);
1505
1506         if (tcp_checksum_complete(skb)) {
1507                 inet_twsk_put(inet_twsk(sk));
1508                 goto csum_error;
1509         }
1510
1511         switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) {
1512         case TCP_TW_SYN:
1513         {
1514                 struct sock *sk2;
1515
1516                 sk2 = inet6_lookup_listener(dev_net(skb->dev), &tcp_hashinfo,
1517                                             &ipv6_hdr(skb)->saddr, th->source,
1518                                             &ipv6_hdr(skb)->daddr,
1519                                             ntohs(th->dest), tcp_v6_iif(skb));
1520                 if (sk2) {
1521                         struct inet_timewait_sock *tw = inet_twsk(sk);
1522                         inet_twsk_deschedule_put(tw);
1523                         sk = sk2;
1524                         tcp_v6_restore_cb(skb);
1525                         goto process;
1526                 }
1527                 /* Fall through to ACK */
1528         }
1529         case TCP_TW_ACK:
1530                 tcp_v6_timewait_ack(sk, skb);
1531                 break;
1532         case TCP_TW_RST:
1533                 tcp_v6_restore_cb(skb);
1534                 goto no_tcp_socket;
1535         case TCP_TW_SUCCESS:
1536                 ;
1537         }
1538         goto discard_it;
1539 }
1540
1541 static void tcp_v6_early_demux(struct sk_buff *skb)
1542 {
1543         const struct ipv6hdr *hdr;
1544         const struct tcphdr *th;
1545         struct sock *sk;
1546
1547         if (skb->pkt_type != PACKET_HOST)
1548                 return;
1549
1550         if (!pskb_may_pull(skb, skb_transport_offset(skb) + sizeof(struct tcphdr)))
1551                 return;
1552
1553         hdr = ipv6_hdr(skb);
1554         th = tcp_hdr(skb);
1555
1556         if (th->doff < sizeof(struct tcphdr) / 4)
1557                 return;
1558
1559         /* Note : We use inet6_iif() here, not tcp_v6_iif() */
1560         sk = __inet6_lookup_established(dev_net(skb->dev), &tcp_hashinfo,
1561                                         &hdr->saddr, th->source,
1562                                         &hdr->daddr, ntohs(th->dest),
1563                                         inet6_iif(skb));
1564         if (sk) {
1565                 skb->sk = sk;
1566                 skb->destructor = sock_edemux;
1567                 if (sk_fullsock(sk)) {
1568                         struct dst_entry *dst = READ_ONCE(sk->sk_rx_dst);
1569
1570                         if (dst)
1571                                 dst = dst_check(dst, inet6_sk(sk)->rx_dst_cookie);
1572                         if (dst &&
1573                             inet_sk(sk)->rx_dst_ifindex == skb->skb_iif)
1574                                 skb_dst_set_noref(skb, dst);
1575                 }
1576         }
1577 }
1578
1579 static struct timewait_sock_ops tcp6_timewait_sock_ops = {
1580         .twsk_obj_size  = sizeof(struct tcp6_timewait_sock),
1581         .twsk_unique    = tcp_twsk_unique,
1582         .twsk_destructor = tcp_twsk_destructor,
1583 };
1584
1585 static const struct inet_connection_sock_af_ops ipv6_specific = {
1586         .queue_xmit        = inet6_csk_xmit,
1587         .send_check        = tcp_v6_send_check,
1588         .rebuild_header    = inet6_sk_rebuild_header,
1589         .sk_rx_dst_set     = inet6_sk_rx_dst_set,
1590         .conn_request      = tcp_v6_conn_request,
1591         .syn_recv_sock     = tcp_v6_syn_recv_sock,
1592         .net_header_len    = sizeof(struct ipv6hdr),
1593         .net_frag_header_len = sizeof(struct frag_hdr),
1594         .setsockopt        = ipv6_setsockopt,
1595         .getsockopt        = ipv6_getsockopt,
1596         .addr2sockaddr     = inet6_csk_addr2sockaddr,
1597         .sockaddr_len      = sizeof(struct sockaddr_in6),
1598         .bind_conflict     = inet6_csk_bind_conflict,
1599 #ifdef CONFIG_COMPAT
1600         .compat_setsockopt = compat_ipv6_setsockopt,
1601         .compat_getsockopt = compat_ipv6_getsockopt,
1602 #endif
1603         .mtu_reduced       = tcp_v6_mtu_reduced,
1604 };
1605
1606 #ifdef CONFIG_TCP_MD5SIG
1607 static const struct tcp_sock_af_ops tcp_sock_ipv6_specific = {
1608         .md5_lookup     =       tcp_v6_md5_lookup,
1609         .calc_md5_hash  =       tcp_v6_md5_hash_skb,
1610         .md5_parse      =       tcp_v6_parse_md5_keys,
1611 };
1612 #endif
1613
1614 /*
1615  *      TCP over IPv4 via INET6 API
1616  */
1617 static const struct inet_connection_sock_af_ops ipv6_mapped = {
1618         .queue_xmit        = ip_queue_xmit,
1619         .send_check        = tcp_v4_send_check,
1620         .rebuild_header    = inet_sk_rebuild_header,
1621         .sk_rx_dst_set     = inet_sk_rx_dst_set,
1622         .conn_request      = tcp_v6_conn_request,
1623         .syn_recv_sock     = tcp_v6_syn_recv_sock,
1624         .net_header_len    = sizeof(struct iphdr),
1625         .setsockopt        = ipv6_setsockopt,
1626         .getsockopt        = ipv6_getsockopt,
1627         .addr2sockaddr     = inet6_csk_addr2sockaddr,
1628         .sockaddr_len      = sizeof(struct sockaddr_in6),
1629         .bind_conflict     = inet6_csk_bind_conflict,
1630 #ifdef CONFIG_COMPAT
1631         .compat_setsockopt = compat_ipv6_setsockopt,
1632         .compat_getsockopt = compat_ipv6_getsockopt,
1633 #endif
1634         .mtu_reduced       = tcp_v4_mtu_reduced,
1635 };
1636
1637 #ifdef CONFIG_TCP_MD5SIG
1638 static const struct tcp_sock_af_ops tcp_sock_ipv6_mapped_specific = {
1639         .md5_lookup     =       tcp_v4_md5_lookup,
1640         .calc_md5_hash  =       tcp_v4_md5_hash_skb,
1641         .md5_parse      =       tcp_v6_parse_md5_keys,
1642 };
1643 #endif
1644
1645 /* NOTE: A lot of things set to zero explicitly by call to
1646  *       sk_alloc() so need not be done here.
1647  */
1648 static int tcp_v6_init_sock(struct sock *sk)
1649 {
1650         struct inet_connection_sock *icsk = inet_csk(sk);
1651
1652         tcp_init_sock(sk);
1653
1654         icsk->icsk_af_ops = &ipv6_specific;
1655
1656 #ifdef CONFIG_TCP_MD5SIG
1657         tcp_sk(sk)->af_specific = &tcp_sock_ipv6_specific;
1658 #endif
1659
1660         return 0;
1661 }
1662
1663 static void tcp_v6_destroy_sock(struct sock *sk)
1664 {
1665         tcp_v4_destroy_sock(sk);
1666         inet6_destroy_sock(sk);
1667 }
1668
1669 #ifdef CONFIG_PROC_FS
1670 /* Proc filesystem TCPv6 sock list dumping. */
1671 static void get_openreq6(struct seq_file *seq,
1672                          const struct request_sock *req, int i)
1673 {
1674         long ttd = req->rsk_timer.expires - jiffies;
1675         const struct in6_addr *src = &inet_rsk(req)->ir_v6_loc_addr;
1676         const struct in6_addr *dest = &inet_rsk(req)->ir_v6_rmt_addr;
1677
1678         if (ttd < 0)
1679                 ttd = 0;
1680
1681         seq_printf(seq,
1682                    "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
1683                    "%02X %08X:%08X %02X:%08lX %08X %5u %8d %d %d %pK\n",
1684                    i,
1685                    src->s6_addr32[0], src->s6_addr32[1],
1686                    src->s6_addr32[2], src->s6_addr32[3],
1687                    inet_rsk(req)->ir_num,
1688                    dest->s6_addr32[0], dest->s6_addr32[1],
1689                    dest->s6_addr32[2], dest->s6_addr32[3],
1690                    ntohs(inet_rsk(req)->ir_rmt_port),
1691                    TCP_SYN_RECV,
1692                    0, 0, /* could print option size, but that is af dependent. */
1693                    1,   /* timers active (only the expire timer) */
1694                    jiffies_to_clock_t(ttd),
1695                    req->num_timeout,
1696                    from_kuid_munged(seq_user_ns(seq),
1697                                     sock_i_uid(req->rsk_listener)),
1698                    0,  /* non standard timer */
1699                    0, /* open_requests have no inode */
1700                    0, req);
1701 }
1702
1703 static void get_tcp6_sock(struct seq_file *seq, struct sock *sp, int i)
1704 {
1705         const struct in6_addr *dest, *src;
1706         __u16 destp, srcp;
1707         int timer_active;
1708         unsigned long timer_expires;
1709         const struct inet_sock *inet = inet_sk(sp);
1710         const struct tcp_sock *tp = tcp_sk(sp);
1711         const struct inet_connection_sock *icsk = inet_csk(sp);
1712         const struct fastopen_queue *fastopenq = &icsk->icsk_accept_queue.fastopenq;
1713         int rx_queue;
1714         int state;
1715
1716         dest  = &sp->sk_v6_daddr;
1717         src   = &sp->sk_v6_rcv_saddr;
1718         destp = ntohs(inet->inet_dport);
1719         srcp  = ntohs(inet->inet_sport);
1720
1721         if (icsk->icsk_pending == ICSK_TIME_RETRANS ||
1722             icsk->icsk_pending == ICSK_TIME_EARLY_RETRANS ||
1723             icsk->icsk_pending == ICSK_TIME_LOSS_PROBE) {
1724                 timer_active    = 1;
1725                 timer_expires   = icsk->icsk_timeout;
1726         } else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
1727                 timer_active    = 4;
1728                 timer_expires   = icsk->icsk_timeout;
1729         } else if (timer_pending(&sp->sk_timer)) {
1730                 timer_active    = 2;
1731                 timer_expires   = sp->sk_timer.expires;
1732         } else {
1733                 timer_active    = 0;
1734                 timer_expires = jiffies;
1735         }
1736
1737         state = sk_state_load(sp);
1738         if (state == TCP_LISTEN)
1739                 rx_queue = sp->sk_ack_backlog;
1740         else
1741                 /* Because we don't lock the socket,
1742                  * we might find a transient negative value.
1743                  */
1744                 rx_queue = max_t(int, tp->rcv_nxt - tp->copied_seq, 0);
1745
1746         seq_printf(seq,
1747                    "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
1748                    "%02X %08X:%08X %02X:%08lX %08X %5u %8d %lu %d %pK %lu %lu %u %u %d\n",
1749                    i,
1750                    src->s6_addr32[0], src->s6_addr32[1],
1751                    src->s6_addr32[2], src->s6_addr32[3], srcp,
1752                    dest->s6_addr32[0], dest->s6_addr32[1],
1753                    dest->s6_addr32[2], dest->s6_addr32[3], destp,
1754                    state,
1755                    tp->write_seq - tp->snd_una,
1756                    rx_queue,
1757                    timer_active,
1758                    jiffies_delta_to_clock_t(timer_expires - jiffies),
1759                    icsk->icsk_retransmits,
1760                    from_kuid_munged(seq_user_ns(seq), sock_i_uid(sp)),
1761                    icsk->icsk_probes_out,
1762                    sock_i_ino(sp),
1763                    atomic_read(&sp->sk_refcnt), sp,
1764                    jiffies_to_clock_t(icsk->icsk_rto),
1765                    jiffies_to_clock_t(icsk->icsk_ack.ato),
1766                    (icsk->icsk_ack.quick << 1) | icsk->icsk_ack.pingpong,
1767                    tp->snd_cwnd,
1768                    state == TCP_LISTEN ?
1769                         fastopenq->max_qlen :
1770                         (tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh)
1771                    );
1772 }
1773
1774 static void get_timewait6_sock(struct seq_file *seq,
1775                                struct inet_timewait_sock *tw, int i)
1776 {
1777         long delta = tw->tw_timer.expires - jiffies;
1778         const struct in6_addr *dest, *src;
1779         __u16 destp, srcp;
1780
1781         dest = &tw->tw_v6_daddr;
1782         src  = &tw->tw_v6_rcv_saddr;
1783         destp = ntohs(tw->tw_dport);
1784         srcp  = ntohs(tw->tw_sport);
1785
1786         seq_printf(seq,
1787                    "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
1788                    "%02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK\n",
1789                    i,
1790                    src->s6_addr32[0], src->s6_addr32[1],
1791                    src->s6_addr32[2], src->s6_addr32[3], srcp,
1792                    dest->s6_addr32[0], dest->s6_addr32[1],
1793                    dest->s6_addr32[2], dest->s6_addr32[3], destp,
1794                    tw->tw_substate, 0, 0,
1795                    3, jiffies_delta_to_clock_t(delta), 0, 0, 0, 0,
1796                    atomic_read(&tw->tw_refcnt), tw);
1797 }
1798
1799 static int tcp6_seq_show(struct seq_file *seq, void *v)
1800 {
1801         struct tcp_iter_state *st;
1802         struct sock *sk = v;
1803
1804         if (v == SEQ_START_TOKEN) {
1805                 seq_puts(seq,
1806                          "  sl  "
1807                          "local_address                         "
1808                          "remote_address                        "
1809                          "st tx_queue rx_queue tr tm->when retrnsmt"
1810                          "   uid  timeout inode\n");
1811                 goto out;
1812         }
1813         st = seq->private;
1814
1815         if (sk->sk_state == TCP_TIME_WAIT)
1816                 get_timewait6_sock(seq, v, st->num);
1817         else if (sk->sk_state == TCP_NEW_SYN_RECV)
1818                 get_openreq6(seq, v, st->num);
1819         else
1820                 get_tcp6_sock(seq, v, st->num);
1821 out:
1822         return 0;
1823 }
1824
1825 static const struct file_operations tcp6_afinfo_seq_fops = {
1826         .owner   = THIS_MODULE,
1827         .open    = tcp_seq_open,
1828         .read    = seq_read,
1829         .llseek  = seq_lseek,
1830         .release = seq_release_net
1831 };
1832
1833 static struct tcp_seq_afinfo tcp6_seq_afinfo = {
1834         .name           = "tcp6",
1835         .family         = AF_INET6,
1836         .seq_fops       = &tcp6_afinfo_seq_fops,
1837         .seq_ops        = {
1838                 .show           = tcp6_seq_show,
1839         },
1840 };
1841
1842 int __net_init tcp6_proc_init(struct net *net)
1843 {
1844         return tcp_proc_register(net, &tcp6_seq_afinfo);
1845 }
1846
1847 void tcp6_proc_exit(struct net *net)
1848 {
1849         tcp_proc_unregister(net, &tcp6_seq_afinfo);
1850 }
1851 #endif
1852
1853 static void tcp_v6_clear_sk(struct sock *sk, int size)
1854 {
1855         struct inet_sock *inet = inet_sk(sk);
1856
1857         /* we do not want to clear pinet6 field, because of RCU lookups */
1858         sk_prot_clear_nulls(sk, offsetof(struct inet_sock, pinet6));
1859
1860         size -= offsetof(struct inet_sock, pinet6) + sizeof(inet->pinet6);
1861         memset(&inet->pinet6 + 1, 0, size);
1862 }
1863
1864 struct proto tcpv6_prot = {
1865         .name                   = "TCPv6",
1866         .owner                  = THIS_MODULE,
1867         .close                  = tcp_close,
1868         .connect                = tcp_v6_connect,
1869         .disconnect             = tcp_disconnect,
1870         .accept                 = inet_csk_accept,
1871         .ioctl                  = tcp_ioctl,
1872         .init                   = tcp_v6_init_sock,
1873         .destroy                = tcp_v6_destroy_sock,
1874         .shutdown               = tcp_shutdown,
1875         .setsockopt             = tcp_setsockopt,
1876         .getsockopt             = tcp_getsockopt,
1877         .recvmsg                = tcp_recvmsg,
1878         .sendmsg                = tcp_sendmsg,
1879         .sendpage               = tcp_sendpage,
1880         .backlog_rcv            = tcp_v6_do_rcv,
1881         .release_cb             = tcp_release_cb,
1882         .hash                   = inet_hash,
1883         .unhash                 = inet_unhash,
1884         .get_port               = inet_csk_get_port,
1885         .enter_memory_pressure  = tcp_enter_memory_pressure,
1886         .stream_memory_free     = tcp_stream_memory_free,
1887         .sockets_allocated      = &tcp_sockets_allocated,
1888         .memory_allocated       = &tcp_memory_allocated,
1889         .memory_pressure        = &tcp_memory_pressure,
1890         .orphan_count           = &tcp_orphan_count,
1891         .sysctl_mem             = sysctl_tcp_mem,
1892         .sysctl_wmem            = sysctl_tcp_wmem,
1893         .sysctl_rmem            = sysctl_tcp_rmem,
1894         .max_header             = MAX_TCP_HEADER,
1895         .obj_size               = sizeof(struct tcp6_sock),
1896         .slab_flags             = SLAB_DESTROY_BY_RCU,
1897         .twsk_prot              = &tcp6_timewait_sock_ops,
1898         .rsk_prot               = &tcp6_request_sock_ops,
1899         .h.hashinfo             = &tcp_hashinfo,
1900         .no_autobind            = true,
1901 #ifdef CONFIG_COMPAT
1902         .compat_setsockopt      = compat_tcp_setsockopt,
1903         .compat_getsockopt      = compat_tcp_getsockopt,
1904 #endif
1905 #ifdef CONFIG_MEMCG_KMEM
1906         .proto_cgroup           = tcp_proto_cgroup,
1907 #endif
1908         .clear_sk               = tcp_v6_clear_sk,
1909         .diag_destroy           = tcp_abort,
1910 };
1911
1912 static const struct inet6_protocol tcpv6_protocol = {
1913         .early_demux    =       tcp_v6_early_demux,
1914         .handler        =       tcp_v6_rcv,
1915         .err_handler    =       tcp_v6_err,
1916         .flags          =       INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
1917 };
1918
1919 static struct inet_protosw tcpv6_protosw = {
1920         .type           =       SOCK_STREAM,
1921         .protocol       =       IPPROTO_TCP,
1922         .prot           =       &tcpv6_prot,
1923         .ops            =       &inet6_stream_ops,
1924         .flags          =       INET_PROTOSW_PERMANENT |
1925                                 INET_PROTOSW_ICSK,
1926 };
1927
1928 static int __net_init tcpv6_net_init(struct net *net)
1929 {
1930         return inet_ctl_sock_create(&net->ipv6.tcp_sk, PF_INET6,
1931                                     SOCK_RAW, IPPROTO_TCP, net);
1932 }
1933
1934 static void __net_exit tcpv6_net_exit(struct net *net)
1935 {
1936         inet_ctl_sock_destroy(net->ipv6.tcp_sk);
1937 }
1938
1939 static void __net_exit tcpv6_net_exit_batch(struct list_head *net_exit_list)
1940 {
1941         inet_twsk_purge(&tcp_hashinfo, &tcp_death_row, AF_INET6);
1942 }
1943
1944 static struct pernet_operations tcpv6_net_ops = {
1945         .init       = tcpv6_net_init,
1946         .exit       = tcpv6_net_exit,
1947         .exit_batch = tcpv6_net_exit_batch,
1948 };
1949
1950 int __init tcpv6_init(void)
1951 {
1952         int ret;
1953
1954         ret = inet6_add_protocol(&tcpv6_protocol, IPPROTO_TCP);
1955         if (ret)
1956                 goto out;
1957
1958         /* register inet6 protocol */
1959         ret = inet6_register_protosw(&tcpv6_protosw);
1960         if (ret)
1961                 goto out_tcpv6_protocol;
1962
1963         ret = register_pernet_subsys(&tcpv6_net_ops);
1964         if (ret)
1965                 goto out_tcpv6_protosw;
1966 out:
1967         return ret;
1968
1969 out_tcpv6_protosw:
1970         inet6_unregister_protosw(&tcpv6_protosw);
1971 out_tcpv6_protocol:
1972         inet6_del_protocol(&tcpv6_protocol, IPPROTO_TCP);
1973         goto out;
1974 }
1975
1976 void tcpv6_exit(void)
1977 {
1978         unregister_pernet_subsys(&tcpv6_net_ops);
1979         inet6_unregister_protosw(&tcpv6_protosw);
1980         inet6_del_protocol(&tcpv6_protocol, IPPROTO_TCP);
1981 }