kernel/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         tcp_v6_send_ack(sk, skb, (sk->sk_state == TCP_LISTEN) ?
 936                         tcp_rsk(req)->snt_isn + 1 : tcp_sk(sk)->snd_nxt,
 937                         tcp_rsk(req)->rcv_nxt, req->rsk_rcv_wnd,
 938                         tcp_time_stamp, req->ts_recent, sk->sk_bound_dev_if,
 939                         tcp_v6_md5_do_lookup(sk, &ipv6_hdr(skb)->daddr),
 940                         0, 0);
 941 }
 942
 943
 944 static struct sock *tcp_v6_cookie_check(struct sock *sk, struct sk_buff *skb)
 945 {
 946 #ifdef CONFIG_SYN_COOKIES
 947         const struct tcphdr *th = tcp_hdr(skb);
 948
 949         if (!th->syn)
 950                 sk = cookie_v6_check(sk, skb);
 951 #endif
 952         return sk;
 953 }
 954
 955 static int tcp_v6_conn_request(struct sock *sk, struct sk_buff *skb)
 956 {
 957         if (skb->protocol == htons(ETH_P_IP))
 958                 return tcp_v4_conn_request(sk, skb);
 959
 960         if (!ipv6_unicast_destination(skb))
 961                 goto drop;
 962
 963         return tcp_conn_request(&tcp6_request_sock_ops,
 964                                 &tcp_request_sock_ipv6_ops, sk, skb);
 965
 966 drop:
 967         NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
 968         return 0; /* don't send reset */
 969 }
 970
 971 static struct sock *tcp_v6_syn_recv_sock(const struct sock *sk, struct sk_buff *skb,
 972                                          struct request_sock *req,
 973                                          struct dst_entry *dst,
 974                                          struct request_sock *req_unhash,
 975                                          bool *own_req)
 976 {
 977         struct inet_request_sock *ireq;
 978         struct ipv6_pinfo *newnp;
 979         const struct ipv6_pinfo *np = inet6_sk(sk);
 980         struct ipv6_txoptions *opt;
 981         struct tcp6_sock *newtcp6sk;
 982         struct inet_sock *newinet;
 983         struct tcp_sock *newtp;
 984         struct sock *newsk;
 985 #ifdef CONFIG_TCP_MD5SIG
 986         struct tcp_md5sig_key *key;
 987 #endif
 988         struct flowi6 fl6;
 989
 990         if (skb->protocol == htons(ETH_P_IP)) {
 991                 /*
 992                  *      v6 mapped
 993                  */
 994
 995                 newsk = tcp_v4_syn_recv_sock(sk, skb, req, dst,
 996                                              req_unhash, own_req);
 997
 998                 if (!newsk)
 999                         return NULL;
1000
1001                 newtcp6sk = (struct tcp6_sock *)newsk;
1002                 inet_sk(newsk)->pinet6 = &newtcp6sk->inet6;
1003
1004                 newinet = inet_sk(newsk);
1005                 newnp = inet6_sk(newsk);
1006                 newtp = tcp_sk(newsk);
1007
1008                 memcpy(newnp, np, sizeof(struct ipv6_pinfo));
1009
1010                 newnp->saddr = newsk->sk_v6_rcv_saddr;
1011
1012                 inet_csk(newsk)->icsk_af_ops = &ipv6_mapped;
1013                 newsk->sk_backlog_rcv = tcp_v4_do_rcv;
1014 #ifdef CONFIG_TCP_MD5SIG
1015                 newtp->af_specific = &tcp_sock_ipv6_mapped_specific;
1016 #endif
1017
1018                 newnp->ipv6_ac_list = NULL;
1019                 newnp->ipv6_fl_list = NULL;
1020                 newnp->pktoptions  = NULL;
1021                 newnp->opt         = NULL;
1022                 newnp->mcast_oif   = tcp_v6_iif(skb);
1023                 newnp->mcast_hops  = ipv6_hdr(skb)->hop_limit;
1024                 newnp->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(skb));
1025                 if (np->repflow)
1026                         newnp->flow_label = ip6_flowlabel(ipv6_hdr(skb));
1027
1028                 /*
1029                  * No need to charge this sock to the relevant IPv6 refcnt debug socks count
1030                  * here, tcp_create_openreq_child now does this for us, see the comment in
1031                  * that function for the gory details. -acme
1032                  */
1033
1034                 /* It is tricky place. Until this moment IPv4 tcp
1035                    worked with IPv6 icsk.icsk_af_ops.
1036                    Sync it now.
1037                  */
1038                 tcp_sync_mss(newsk, inet_csk(newsk)->icsk_pmtu_cookie);
1039
1040                 return newsk;
1041         }
1042
1043         ireq = inet_rsk(req);
1044
1045         if (sk_acceptq_is_full(sk))
1046                 goto out_overflow;
1047
1048         if (!dst) {
1049                 dst = inet6_csk_route_req(sk, &fl6, req, IPPROTO_TCP);
1050                 if (!dst)
1051                         goto out;
1052         }
1053
1054         newsk = tcp_create_openreq_child(sk, req, skb);
1055         if (!newsk)
1056                 goto out_nonewsk;
1057
1058         /*
1059          * No need to charge this sock to the relevant IPv6 refcnt debug socks
1060          * count here, tcp_create_openreq_child now does this for us, see the
1061          * comment in that function for the gory details. -acme
1062          */
1063
1064         newsk->sk_gso_type = SKB_GSO_TCPV6;
1065         ip6_dst_store(newsk, dst, NULL, NULL);
1066         inet6_sk_rx_dst_set(newsk, skb);
1067
1068         newtcp6sk = (struct tcp6_sock *)newsk;
1069         inet_sk(newsk)->pinet6 = &newtcp6sk->inet6;
1070
1071         newtp = tcp_sk(newsk);
1072         newinet = inet_sk(newsk);
1073         newnp = inet6_sk(newsk);
1074
1075         memcpy(newnp, np, sizeof(struct ipv6_pinfo));
1076
1077         newsk->sk_v6_daddr = ireq->ir_v6_rmt_addr;
1078         newnp->saddr = ireq->ir_v6_loc_addr;
1079         newsk->sk_v6_rcv_saddr = ireq->ir_v6_loc_addr;
1080         newsk->sk_bound_dev_if = ireq->ir_iif;
1081
1082         /* Now IPv6 options...
1083
1084            First: no IPv4 options.
1085          */
1086         newinet->inet_opt = NULL;
1087         newnp->ipv6_ac_list = NULL;
1088         newnp->ipv6_fl_list = NULL;
1089
1090         /* Clone RX bits */
1091         newnp->rxopt.all = np->rxopt.all;
1092
1093         newnp->pktoptions = NULL;
1094         newnp->opt        = NULL;
1095         newnp->mcast_oif  = tcp_v6_iif(skb);
1096         newnp->mcast_hops = ipv6_hdr(skb)->hop_limit;
1097         newnp->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(skb));
1098         if (np->repflow)
1099                 newnp->flow_label = ip6_flowlabel(ipv6_hdr(skb));
1100
1101         /* Clone native IPv6 options from listening socket (if any)
1102
1103            Yes, keeping reference count would be much more clever,
1104            but we make one more one thing there: reattach optmem
1105            to newsk.
1106          */
1107         opt = rcu_dereference(np->opt);
1108         if (opt) {
1109                 opt = ipv6_dup_options(newsk, opt);
1110                 RCU_INIT_POINTER(newnp->opt, opt);
1111         }
1112         inet_csk(newsk)->icsk_ext_hdr_len = 0;
1113         if (opt)
1114                 inet_csk(newsk)->icsk_ext_hdr_len = opt->opt_nflen +
1115                                                     opt->opt_flen;
1116
1117         tcp_ca_openreq_child(newsk, dst);
1118
1119         tcp_sync_mss(newsk, dst_mtu(dst));
1120         newtp->advmss = dst_metric_advmss(dst);
1121         if (tcp_sk(sk)->rx_opt.user_mss &&
1122             tcp_sk(sk)->rx_opt.user_mss < newtp->advmss)
1123                 newtp->advmss = tcp_sk(sk)->rx_opt.user_mss;
1124
1125         tcp_initialize_rcv_mss(newsk);
1126
1127         newinet->inet_daddr = newinet->inet_saddr = LOOPBACK4_IPV6;
1128         newinet->inet_rcv_saddr = LOOPBACK4_IPV6;
1129
1130 #ifdef CONFIG_TCP_MD5SIG
1131         /* Copy over the MD5 key from the original socket */
1132         key = tcp_v6_md5_do_lookup(sk, &newsk->sk_v6_daddr);
1133         if (key) {
1134                 /* We're using one, so create a matching key
1135                  * on the newsk structure. If we fail to get
1136                  * memory, then we end up not copying the key
1137                  * across. Shucks.
1138                  */
1139                 tcp_md5_do_add(newsk, (union tcp_md5_addr *)&newsk->sk_v6_daddr,
1140                                AF_INET6, key->key, key->keylen,
1141                                sk_gfp_atomic(sk, GFP_ATOMIC));
1142         }
1143 #endif
1144
1145         if (__inet_inherit_port(sk, newsk) < 0) {
1146                 inet_csk_prepare_forced_close(newsk);
1147                 tcp_done(newsk);
1148                 goto out;
1149         }
1150         *own_req = inet_ehash_nolisten(newsk, req_to_sk(req_unhash));
1151         if (*own_req) {
1152                 tcp_move_syn(newtp, req);
1153
1154                 /* Clone pktoptions received with SYN, if we own the req */
1155                 if (ireq->pktopts) {
1156                         newnp->pktoptions = skb_clone(ireq->pktopts,
1157                                                       sk_gfp_atomic(sk, GFP_ATOMIC));
1158                         consume_skb(ireq->pktopts);
1159                         ireq->pktopts = NULL;
1160                         if (newnp->pktoptions)
1161                                 skb_set_owner_r(newnp->pktoptions, newsk);
1162                 }
1163         }
1164
1165         return newsk;
1166
1167 out_overflow:
1168         NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
1169 out_nonewsk:
1170         dst_release(dst);
1171 out:
1172         NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
1173         return NULL;
1174 }
1175
1176 /* The socket must have it's spinlock held when we get
1177  * here, unless it is a TCP_LISTEN socket.
1178  *
1179  * We have a potential double-lock case here, so even when
1180  * doing backlog processing we use the BH locking scheme.
1181  * This is because we cannot sleep with the original spinlock
1182  * held.
1183  */
1184 static int tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb)
1185 {
1186         struct ipv6_pinfo *np = inet6_sk(sk);
1187         struct tcp_sock *tp;
1188         struct sk_buff *opt_skb = NULL;
1189
1190         /* Imagine: socket is IPv6. IPv4 packet arrives,
1191            goes to IPv4 receive handler and backlogged.
1192            From backlog it always goes here. Kerboom...
1193            Fortunately, tcp_rcv_established and rcv_established
1194            handle them correctly, but it is not case with
1195            tcp_v6_hnd_req and tcp_v6_send_reset().   --ANK
1196          */
1197
1198         if (skb->protocol == htons(ETH_P_IP))
1199                 return tcp_v4_do_rcv(sk, skb);
1200
1201         if (sk_filter(sk, skb))
1202                 goto discard;
1203
1204         /*
1205          *      socket locking is here for SMP purposes as backlog rcv
1206          *      is currently called with bh processing disabled.
1207          */
1208
1209         /* Do Stevens' IPV6_PKTOPTIONS.
1210
1211            Yes, guys, it is the only place in our code, where we
1212            may make it not affecting IPv4.
1213            The rest of code is protocol independent,
1214            and I do not like idea to uglify IPv4.
1215
1216            Actually, all the idea behind IPV6_PKTOPTIONS
1217            looks not very well thought. For now we latch
1218            options, received in the last packet, enqueued
1219            by tcp. Feel free to propose better solution.
1220                                                --ANK (980728)
1221          */
1222         if (np->rxopt.all)
1223                 opt_skb = skb_clone(skb, sk_gfp_atomic(sk, GFP_ATOMIC));
1224
1225         if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
1226                 struct dst_entry *dst = sk->sk_rx_dst;
1227
1228                 sock_rps_save_rxhash(sk, skb);
1229                 sk_mark_napi_id(sk, skb);
1230                 if (dst) {
1231                         if (inet_sk(sk)->rx_dst_ifindex != skb->skb_iif ||
1232                             dst->ops->check(dst, np->rx_dst_cookie) == NULL) {
1233                                 dst_release(dst);
1234                                 sk->sk_rx_dst = NULL;
1235                         }
1236                 }
1237
1238                 tcp_rcv_established(sk, skb, tcp_hdr(skb), skb->len);
1239                 if (opt_skb)
1240                         goto ipv6_pktoptions;
1241                 return 0;
1242         }
1243
1244         if (tcp_checksum_complete(skb))
1245                 goto csum_err;
1246
1247         if (sk->sk_state == TCP_LISTEN) {
1248                 struct sock *nsk = tcp_v6_cookie_check(sk, skb);
1249
1250                 if (!nsk)
1251                         goto discard;
1252
1253                 if (nsk != sk) {
1254                         sock_rps_save_rxhash(nsk, skb);
1255                         sk_mark_napi_id(nsk, skb);
1256                         if (tcp_child_process(sk, nsk, skb))
1257                                 goto reset;
1258                         if (opt_skb)
1259                                 __kfree_skb(opt_skb);
1260                         return 0;
1261                 }
1262         } else
1263                 sock_rps_save_rxhash(sk, skb);
1264
1265         if (tcp_rcv_state_process(sk, skb))
1266                 goto reset;
1267         if (opt_skb)
1268                 goto ipv6_pktoptions;
1269         return 0;
1270
1271 reset:
1272         tcp_v6_send_reset(sk, skb);
1273 discard:
1274         if (opt_skb)
1275                 __kfree_skb(opt_skb);
1276         kfree_skb(skb);
1277         return 0;
1278 csum_err:
1279         TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_CSUMERRORS);
1280         TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_INERRS);
1281         goto discard;
1282
1283
1284 ipv6_pktoptions:
1285         /* Do you ask, what is it?
1286
1287            1. skb was enqueued by tcp.
1288            2. skb is added to tail of read queue, rather than out of order.
1289            3. socket is not in passive state.
1290            4. Finally, it really contains options, which user wants to receive.
1291          */
1292         tp = tcp_sk(sk);
1293         if (TCP_SKB_CB(opt_skb)->end_seq == tp->rcv_nxt &&
1294             !((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN))) {
1295                 if (np->rxopt.bits.rxinfo || np->rxopt.bits.rxoinfo)
1296                         np->mcast_oif = tcp_v6_iif(opt_skb);
1297                 if (np->rxopt.bits.rxhlim || np->rxopt.bits.rxohlim)
1298                         np->mcast_hops = ipv6_hdr(opt_skb)->hop_limit;
1299                 if (np->rxopt.bits.rxflow || np->rxopt.bits.rxtclass)
1300                         np->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(opt_skb));
1301                 if (np->repflow)
1302                         np->flow_label = ip6_flowlabel(ipv6_hdr(opt_skb));
1303                 if (ipv6_opt_accepted(sk, opt_skb, &TCP_SKB_CB(opt_skb)->header.h6)) {
1304                         skb_set_owner_r(opt_skb, sk);
1305                         opt_skb = xchg(&np->pktoptions, opt_skb);
1306                 } else {
1307                         __kfree_skb(opt_skb);
1308                         opt_skb = xchg(&np->pktoptions, NULL);
1309                 }
1310         }
1311
1312         kfree_skb(opt_skb);
1313         return 0;
1314 }
1315
1316 static void tcp_v6_fill_cb(struct sk_buff *skb, const struct ipv6hdr *hdr,
1317                            const struct tcphdr *th)
1318 {
1319         /* This is tricky: we move IP6CB at its correct location into
1320          * TCP_SKB_CB(). It must be done after xfrm6_policy_check(), because
1321          * _decode_session6() uses IP6CB().
1322          * barrier() makes sure compiler won't play aliasing games.
1323          */
1324         memmove(&TCP_SKB_CB(skb)->header.h6, IP6CB(skb),
1325                 sizeof(struct inet6_skb_parm));
1326         barrier();
1327
1328         TCP_SKB_CB(skb)->seq = ntohl(th->seq);
1329         TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
1330                                     skb->len - th->doff*4);
1331         TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
1332         TCP_SKB_CB(skb)->tcp_flags = tcp_flag_byte(th);
1333         TCP_SKB_CB(skb)->tcp_tw_isn = 0;
1334         TCP_SKB_CB(skb)->ip_dsfield = ipv6_get_dsfield(hdr);
1335         TCP_SKB_CB(skb)->sacked = 0;
1336 }
1337
1338 static void tcp_v6_restore_cb(struct sk_buff *skb)
1339 {
1340         /* We need to move header back to the beginning if xfrm6_policy_check()
1341          * and tcp_v6_fill_cb() are going to be called again.
1342          */
1343         memmove(IP6CB(skb), &TCP_SKB_CB(skb)->header.h6,
1344                 sizeof(struct inet6_skb_parm));
1345 }
1346
1347 static int tcp_v6_rcv(struct sk_buff *skb)
1348 {
1349         const struct tcphdr *th;
1350         const struct ipv6hdr *hdr;
1351         struct sock *sk;
1352         int ret;
1353         struct net *net = dev_net(skb->dev);
1354
1355         if (skb->pkt_type != PACKET_HOST)
1356                 goto discard_it;
1357
1358         /*
1359          *      Count it even if it's bad.
1360          */
1361         TCP_INC_STATS_BH(net, TCP_MIB_INSEGS);
1362
1363         if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
1364                 goto discard_it;
1365
1366         th = tcp_hdr(skb);
1367
1368         if (th->doff < sizeof(struct tcphdr)/4)
1369                 goto bad_packet;
1370         if (!pskb_may_pull(skb, th->doff*4))
1371                 goto discard_it;
1372
1373         if (skb_checksum_init(skb, IPPROTO_TCP, ip6_compute_pseudo))
1374                 goto csum_error;
1375
1376         th = tcp_hdr(skb);
1377         hdr = ipv6_hdr(skb);
1378
1379 lookup:
1380         sk = __inet6_lookup_skb(&tcp_hashinfo, skb, th->source, th->dest,
1381                                 inet6_iif(skb));
1382         if (!sk)
1383                 goto no_tcp_socket;
1384
1385 process:
1386         if (sk->sk_state == TCP_TIME_WAIT)
1387                 goto do_time_wait;
1388
1389         if (sk->sk_state == TCP_NEW_SYN_RECV) {
1390                 struct request_sock *req = inet_reqsk(sk);
1391                 struct sock *nsk;
1392
1393                 sk = req->rsk_listener;
1394                 tcp_v6_fill_cb(skb, hdr, th);
1395                 if (tcp_v6_inbound_md5_hash(sk, skb)) {
1396                         reqsk_put(req);
1397                         goto discard_it;
1398                 }
1399                 if (unlikely(sk->sk_state != TCP_LISTEN)) {
1400                         inet_csk_reqsk_queue_drop_and_put(sk, req);
1401                         goto lookup;
1402                 }
1403                 sock_hold(sk);
1404                 nsk = tcp_check_req(sk, skb, req, false);
1405                 if (!nsk) {
1406                         reqsk_put(req);
1407                         goto discard_and_relse;
1408                 }
1409                 if (nsk == sk) {
1410                         reqsk_put(req);
1411                         tcp_v6_restore_cb(skb);
1412                 } else if (tcp_child_process(sk, nsk, skb)) {
1413                         tcp_v6_send_reset(nsk, skb);
1414                         goto discard_and_relse;
1415                 } else {
1416                         sock_put(sk);
1417                         return 0;
1418                 }
1419         }
1420         if (hdr->hop_limit < inet6_sk(sk)->min_hopcount) {
1421                 NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP);
1422                 goto discard_and_relse;
1423         }
1424
1425         if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb))
1426                 goto discard_and_relse;
1427
1428         tcp_v6_fill_cb(skb, hdr, th);
1429
1430         if (tcp_v6_inbound_md5_hash(sk, skb))
1431                 goto discard_and_relse;
1432
1433         if (sk_filter(sk, skb))
1434                 goto discard_and_relse;
1435
1436         skb->dev = NULL;
1437
1438         if (sk->sk_state == TCP_LISTEN) {
1439                 ret = tcp_v6_do_rcv(sk, skb);
1440                 goto put_and_return;
1441         }
1442
1443         sk_incoming_cpu_update(sk);
1444
1445         bh_lock_sock_nested(sk);
1446         tcp_sk(sk)->segs_in += max_t(u16, 1, skb_shinfo(skb)->gso_segs);
1447         ret = 0;
1448         if (!sock_owned_by_user(sk)) {
1449                 if (!tcp_prequeue(sk, skb))
1450                         ret = tcp_v6_do_rcv(sk, skb);
1451         } else if (unlikely(sk_add_backlog(sk, skb,
1452                                            sk->sk_rcvbuf + sk->sk_sndbuf))) {
1453                 bh_unlock_sock(sk);
1454                 NET_INC_STATS_BH(net, LINUX_MIB_TCPBACKLOGDROP);
1455                 goto discard_and_relse;
1456         }
1457         bh_unlock_sock(sk);
1458
1459 put_and_return:
1460         sock_put(sk);
1461         return ret ? -1 : 0;
1462
1463 no_tcp_socket:
1464         if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb))
1465                 goto discard_it;
1466
1467         tcp_v6_fill_cb(skb, hdr, th);
1468
1469         if (tcp_checksum_complete(skb)) {
1470 csum_error:
1471                 TCP_INC_STATS_BH(net, TCP_MIB_CSUMERRORS);
1472 bad_packet:
1473                 TCP_INC_STATS_BH(net, TCP_MIB_INERRS);
1474         } else {
1475                 tcp_v6_send_reset(NULL, skb);
1476         }
1477
1478 discard_it:
1479         kfree_skb(skb);
1480         return 0;
1481
1482 discard_and_relse:
1483         sock_put(sk);
1484         goto discard_it;
1485
1486 do_time_wait:
1487         if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
1488                 inet_twsk_put(inet_twsk(sk));
1489                 goto discard_it;
1490         }
1491
1492         tcp_v6_fill_cb(skb, hdr, th);
1493
1494         if (tcp_checksum_complete(skb)) {
1495                 inet_twsk_put(inet_twsk(sk));
1496                 goto csum_error;
1497         }
1498
1499         switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) {
1500         case TCP_TW_SYN:
1501         {
1502                 struct sock *sk2;
1503
1504                 sk2 = inet6_lookup_listener(dev_net(skb->dev), &tcp_hashinfo,
1505                                             &ipv6_hdr(skb)->saddr, th->source,
1506                                             &ipv6_hdr(skb)->daddr,
1507                                             ntohs(th->dest), tcp_v6_iif(skb));
1508                 if (sk2) {
1509                         struct inet_timewait_sock *tw = inet_twsk(sk);
1510                         inet_twsk_deschedule_put(tw);
1511                         sk = sk2;
1512                         tcp_v6_restore_cb(skb);
1513                         goto process;
1514                 }
1515                 /* Fall through to ACK */
1516         }
1517         case TCP_TW_ACK:
1518                 tcp_v6_timewait_ack(sk, skb);
1519                 break;
1520         case TCP_TW_RST:
1521                 tcp_v6_restore_cb(skb);
1522                 goto no_tcp_socket;
1523         case TCP_TW_SUCCESS:
1524                 ;
1525         }
1526         goto discard_it;
1527 }
1528
1529 static void tcp_v6_early_demux(struct sk_buff *skb)
1530 {
1531         const struct ipv6hdr *hdr;
1532         const struct tcphdr *th;
1533         struct sock *sk;
1534
1535         if (skb->pkt_type != PACKET_HOST)
1536                 return;
1537
1538         if (!pskb_may_pull(skb, skb_transport_offset(skb) + sizeof(struct tcphdr)))
1539                 return;
1540
1541         hdr = ipv6_hdr(skb);
1542         th = tcp_hdr(skb);
1543
1544         if (th->doff < sizeof(struct tcphdr) / 4)
1545                 return;
1546
1547         /* Note : We use inet6_iif() here, not tcp_v6_iif() */
1548         sk = __inet6_lookup_established(dev_net(skb->dev), &tcp_hashinfo,
1549                                         &hdr->saddr, th->source,
1550                                         &hdr->daddr, ntohs(th->dest),
1551                                         inet6_iif(skb));
1552         if (sk) {
1553                 skb->sk = sk;
1554                 skb->destructor = sock_edemux;
1555                 if (sk_fullsock(sk)) {
1556                         struct dst_entry *dst = READ_ONCE(sk->sk_rx_dst);
1557
1558                         if (dst)
1559                                 dst = dst_check(dst, inet6_sk(sk)->rx_dst_cookie);
1560                         if (dst &&
1561                             inet_sk(sk)->rx_dst_ifindex == skb->skb_iif)
1562                                 skb_dst_set_noref(skb, dst);
1563                 }
1564         }
1565 }
1566
1567 static struct timewait_sock_ops tcp6_timewait_sock_ops = {
1568         .twsk_obj_size  = sizeof(struct tcp6_timewait_sock),
1569         .twsk_unique    = tcp_twsk_unique,
1570         .twsk_destructor = tcp_twsk_destructor,
1571 };
1572
1573 static const struct inet_connection_sock_af_ops ipv6_specific = {
1574         .queue_xmit        = inet6_csk_xmit,
1575         .send_check        = tcp_v6_send_check,
1576         .rebuild_header    = inet6_sk_rebuild_header,
1577         .sk_rx_dst_set     = inet6_sk_rx_dst_set,
1578         .conn_request      = tcp_v6_conn_request,
1579         .syn_recv_sock     = tcp_v6_syn_recv_sock,
1580         .net_header_len    = sizeof(struct ipv6hdr),
1581         .net_frag_header_len = sizeof(struct frag_hdr),
1582         .setsockopt        = ipv6_setsockopt,
1583         .getsockopt        = ipv6_getsockopt,
1584         .addr2sockaddr     = inet6_csk_addr2sockaddr,
1585         .sockaddr_len      = sizeof(struct sockaddr_in6),
1586         .bind_conflict     = inet6_csk_bind_conflict,
1587 #ifdef CONFIG_COMPAT
1588         .compat_setsockopt = compat_ipv6_setsockopt,
1589         .compat_getsockopt = compat_ipv6_getsockopt,
1590 #endif
1591         .mtu_reduced       = tcp_v6_mtu_reduced,
1592 };
1593
1594 #ifdef CONFIG_TCP_MD5SIG
1595 static const struct tcp_sock_af_ops tcp_sock_ipv6_specific = {
1596         .md5_lookup     =       tcp_v6_md5_lookup,
1597         .calc_md5_hash  =       tcp_v6_md5_hash_skb,
1598         .md5_parse      =       tcp_v6_parse_md5_keys,
1599 };
1600 #endif
1601
1602 /*
1603  *      TCP over IPv4 via INET6 API
1604  */
1605 static const struct inet_connection_sock_af_ops ipv6_mapped = {
1606         .queue_xmit        = ip_queue_xmit,
1607         .send_check        = tcp_v4_send_check,
1608         .rebuild_header    = inet_sk_rebuild_header,
1609         .sk_rx_dst_set     = inet_sk_rx_dst_set,
1610         .conn_request      = tcp_v6_conn_request,
1611         .syn_recv_sock     = tcp_v6_syn_recv_sock,
1612         .net_header_len    = sizeof(struct iphdr),
1613         .setsockopt        = ipv6_setsockopt,
1614         .getsockopt        = ipv6_getsockopt,
1615         .addr2sockaddr     = inet6_csk_addr2sockaddr,
1616         .sockaddr_len      = sizeof(struct sockaddr_in6),
1617         .bind_conflict     = inet6_csk_bind_conflict,
1618 #ifdef CONFIG_COMPAT
1619         .compat_setsockopt = compat_ipv6_setsockopt,
1620         .compat_getsockopt = compat_ipv6_getsockopt,
1621 #endif
1622         .mtu_reduced       = tcp_v4_mtu_reduced,
1623 };
1624
1625 #ifdef CONFIG_TCP_MD5SIG
1626 static const struct tcp_sock_af_ops tcp_sock_ipv6_mapped_specific = {
1627         .md5_lookup     =       tcp_v4_md5_lookup,
1628         .calc_md5_hash  =       tcp_v4_md5_hash_skb,
1629         .md5_parse      =       tcp_v6_parse_md5_keys,
1630 };
1631 #endif
1632
1633 /* NOTE: A lot of things set to zero explicitly by call to
1634  *       sk_alloc() so need not be done here.
1635  */
1636 static int tcp_v6_init_sock(struct sock *sk)
1637 {
1638         struct inet_connection_sock *icsk = inet_csk(sk);
1639
1640         tcp_init_sock(sk);
1641
1642         icsk->icsk_af_ops = &ipv6_specific;
1643
1644 #ifdef CONFIG_TCP_MD5SIG
1645         tcp_sk(sk)->af_specific = &tcp_sock_ipv6_specific;
1646 #endif
1647
1648         return 0;
1649 }
1650
1651 static void tcp_v6_destroy_sock(struct sock *sk)
1652 {
1653         tcp_v4_destroy_sock(sk);
1654         inet6_destroy_sock(sk);
1655 }
1656
1657 #ifdef CONFIG_PROC_FS
1658 /* Proc filesystem TCPv6 sock list dumping. */
1659 static void get_openreq6(struct seq_file *seq,
1660                          const struct request_sock *req, int i)
1661 {
1662         long ttd = req->rsk_timer.expires - jiffies;
1663         const struct in6_addr *src = &inet_rsk(req)->ir_v6_loc_addr;
1664         const struct in6_addr *dest = &inet_rsk(req)->ir_v6_rmt_addr;
1665
1666         if (ttd < 0)
1667                 ttd = 0;
1668
1669         seq_printf(seq,
1670                    "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
1671                    "%02X %08X:%08X %02X:%08lX %08X %5u %8d %d %d %pK\n",
1672                    i,
1673                    src->s6_addr32[0], src->s6_addr32[1],
1674                    src->s6_addr32[2], src->s6_addr32[3],
1675                    inet_rsk(req)->ir_num,
1676                    dest->s6_addr32[0], dest->s6_addr32[1],
1677                    dest->s6_addr32[2], dest->s6_addr32[3],
1678                    ntohs(inet_rsk(req)->ir_rmt_port),
1679                    TCP_SYN_RECV,
1680                    0, 0, /* could print option size, but that is af dependent. */
1681                    1,   /* timers active (only the expire timer) */
1682                    jiffies_to_clock_t(ttd),
1683                    req->num_timeout,
1684                    from_kuid_munged(seq_user_ns(seq),
1685                                     sock_i_uid(req->rsk_listener)),
1686                    0,  /* non standard timer */
1687                    0, /* open_requests have no inode */
1688                    0, req);
1689 }
1690
1691 static void get_tcp6_sock(struct seq_file *seq, struct sock *sp, int i)
1692 {
1693         const struct in6_addr *dest, *src;
1694         __u16 destp, srcp;
1695         int timer_active;
1696         unsigned long timer_expires;
1697         const struct inet_sock *inet = inet_sk(sp);
1698         const struct tcp_sock *tp = tcp_sk(sp);
1699         const struct inet_connection_sock *icsk = inet_csk(sp);
1700         const struct fastopen_queue *fastopenq = &icsk->icsk_accept_queue.fastopenq;
1701         int rx_queue;
1702         int state;
1703
1704         dest  = &sp->sk_v6_daddr;
1705         src   = &sp->sk_v6_rcv_saddr;
1706         destp = ntohs(inet->inet_dport);
1707         srcp  = ntohs(inet->inet_sport);
1708
1709         if (icsk->icsk_pending == ICSK_TIME_RETRANS) {
1710                 timer_active    = 1;
1711                 timer_expires   = icsk->icsk_timeout;
1712         } else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
1713                 timer_active    = 4;
1714                 timer_expires   = icsk->icsk_timeout;
1715         } else if (timer_pending(&sp->sk_timer)) {
1716                 timer_active    = 2;
1717                 timer_expires   = sp->sk_timer.expires;
1718         } else {
1719                 timer_active    = 0;
1720                 timer_expires = jiffies;
1721         }
1722
1723         state = sk_state_load(sp);
1724         if (state == TCP_LISTEN)
1725                 rx_queue = sp->sk_ack_backlog;
1726         else
1727                 /* Because we don't lock the socket,
1728                  * we might find a transient negative value.
1729                  */
1730                 rx_queue = max_t(int, tp->rcv_nxt - tp->copied_seq, 0);
1731
1732         seq_printf(seq,
1733                    "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
1734                    "%02X %08X:%08X %02X:%08lX %08X %5u %8d %lu %d %pK %lu %lu %u %u %d\n",
1735                    i,
1736                    src->s6_addr32[0], src->s6_addr32[1],
1737                    src->s6_addr32[2], src->s6_addr32[3], srcp,
1738                    dest->s6_addr32[0], dest->s6_addr32[1],
1739                    dest->s6_addr32[2], dest->s6_addr32[3], destp,
1740                    state,
1741                    tp->write_seq - tp->snd_una,
1742                    rx_queue,
1743                    timer_active,
1744                    jiffies_delta_to_clock_t(timer_expires - jiffies),
1745                    icsk->icsk_retransmits,
1746                    from_kuid_munged(seq_user_ns(seq), sock_i_uid(sp)),
1747                    icsk->icsk_probes_out,
1748                    sock_i_ino(sp),
1749                    atomic_read(&sp->sk_refcnt), sp,
1750                    jiffies_to_clock_t(icsk->icsk_rto),
1751                    jiffies_to_clock_t(icsk->icsk_ack.ato),
1752                    (icsk->icsk_ack.quick << 1) | icsk->icsk_ack.pingpong,
1753                    tp->snd_cwnd,
1754                    state == TCP_LISTEN ?
1755                         fastopenq->max_qlen :
1756                         (tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh)
1757                    );
1758 }
1759
1760 static void get_timewait6_sock(struct seq_file *seq,
1761                                struct inet_timewait_sock *tw, int i)
1762 {
1763         long delta = tw->tw_timer.expires - jiffies;
1764         const struct in6_addr *dest, *src;
1765         __u16 destp, srcp;
1766
1767         dest = &tw->tw_v6_daddr;
1768         src  = &tw->tw_v6_rcv_saddr;
1769         destp = ntohs(tw->tw_dport);
1770         srcp  = ntohs(tw->tw_sport);
1771
1772         seq_printf(seq,
1773                    "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
1774                    "%02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK\n",
1775                    i,
1776                    src->s6_addr32[0], src->s6_addr32[1],
1777                    src->s6_addr32[2], src->s6_addr32[3], srcp,
1778                    dest->s6_addr32[0], dest->s6_addr32[1],
1779                    dest->s6_addr32[2], dest->s6_addr32[3], destp,
1780                    tw->tw_substate, 0, 0,
1781                    3, jiffies_delta_to_clock_t(delta), 0, 0, 0, 0,
1782                    atomic_read(&tw->tw_refcnt), tw);
1783 }
1784
1785 static int tcp6_seq_show(struct seq_file *seq, void *v)
1786 {
1787         struct tcp_iter_state *st;
1788         struct sock *sk = v;
1789
1790         if (v == SEQ_START_TOKEN) {
1791                 seq_puts(seq,
1792                          "  sl  "
1793                          "local_address                         "
1794                          "remote_address                        "
1795                          "st tx_queue rx_queue tr tm->when retrnsmt"
1796                          "   uid  timeout inode\n");
1797                 goto out;
1798         }
1799         st = seq->private;
1800
1801         if (sk->sk_state == TCP_TIME_WAIT)
1802                 get_timewait6_sock(seq, v, st->num);
1803         else if (sk->sk_state == TCP_NEW_SYN_RECV)
1804                 get_openreq6(seq, v, st->num);
1805         else
1806                 get_tcp6_sock(seq, v, st->num);
1807 out:
1808         return 0;
1809 }
1810
1811 static const struct file_operations tcp6_afinfo_seq_fops = {
1812         .owner   = THIS_MODULE,
1813         .open    = tcp_seq_open,
1814         .read    = seq_read,
1815         .llseek  = seq_lseek,
1816         .release = seq_release_net
1817 };
1818
1819 static struct tcp_seq_afinfo tcp6_seq_afinfo = {
1820         .name           = "tcp6",
1821         .family         = AF_INET6,
1822         .seq_fops       = &tcp6_afinfo_seq_fops,
1823         .seq_ops        = {
1824                 .show           = tcp6_seq_show,
1825         },
1826 };
1827
1828 int __net_init tcp6_proc_init(struct net *net)
1829 {
1830         return tcp_proc_register(net, &tcp6_seq_afinfo);
1831 }
1832
1833 void tcp6_proc_exit(struct net *net)
1834 {
1835         tcp_proc_unregister(net, &tcp6_seq_afinfo);
1836 }
1837 #endif
1838
1839 static void tcp_v6_clear_sk(struct sock *sk, int size)
1840 {
1841         struct inet_sock *inet = inet_sk(sk);
1842
1843         /* we do not want to clear pinet6 field, because of RCU lookups */
1844         sk_prot_clear_nulls(sk, offsetof(struct inet_sock, pinet6));
1845
1846         size -= offsetof(struct inet_sock, pinet6) + sizeof(inet->pinet6);
1847         memset(&inet->pinet6 + 1, 0, size);
1848 }
1849
1850 struct proto tcpv6_prot = {
1851         .name                   = "TCPv6",
1852         .owner                  = THIS_MODULE,
1853         .close                  = tcp_close,
1854         .connect                = tcp_v6_connect,
1855         .disconnect             = tcp_disconnect,
1856         .accept                 = inet_csk_accept,
1857         .ioctl                  = tcp_ioctl,
1858         .init                   = tcp_v6_init_sock,
1859         .destroy                = tcp_v6_destroy_sock,
1860         .shutdown               = tcp_shutdown,
1861         .setsockopt             = tcp_setsockopt,
1862         .getsockopt             = tcp_getsockopt,
1863         .recvmsg                = tcp_recvmsg,
1864         .sendmsg                = tcp_sendmsg,
1865         .sendpage               = tcp_sendpage,
1866         .backlog_rcv            = tcp_v6_do_rcv,
1867         .release_cb             = tcp_release_cb,
1868         .hash                   = inet_hash,
1869         .unhash                 = inet_unhash,
1870         .get_port               = inet_csk_get_port,
1871         .enter_memory_pressure  = tcp_enter_memory_pressure,
1872         .stream_memory_free     = tcp_stream_memory_free,
1873         .sockets_allocated      = &tcp_sockets_allocated,
1874         .memory_allocated       = &tcp_memory_allocated,
1875         .memory_pressure        = &tcp_memory_pressure,
1876         .orphan_count           = &tcp_orphan_count,
1877         .sysctl_mem             = sysctl_tcp_mem,
1878         .sysctl_wmem            = sysctl_tcp_wmem,
1879         .sysctl_rmem            = sysctl_tcp_rmem,
1880         .max_header             = MAX_TCP_HEADER,
1881         .obj_size               = sizeof(struct tcp6_sock),
1882         .slab_flags             = SLAB_DESTROY_BY_RCU,
1883         .twsk_prot              = &tcp6_timewait_sock_ops,
1884         .rsk_prot               = &tcp6_request_sock_ops,
1885         .h.hashinfo             = &tcp_hashinfo,
1886         .no_autobind            = true,
1887 #ifdef CONFIG_COMPAT
1888         .compat_setsockopt      = compat_tcp_setsockopt,
1889         .compat_getsockopt      = compat_tcp_getsockopt,
1890 #endif
1891 #ifdef CONFIG_MEMCG_KMEM
1892         .proto_cgroup           = tcp_proto_cgroup,
1893 #endif
1894         .clear_sk               = tcp_v6_clear_sk,
1895 };
1896
1897 static const struct inet6_protocol tcpv6_protocol = {
1898         .early_demux    =       tcp_v6_early_demux,
1899         .handler        =       tcp_v6_rcv,
1900         .err_handler    =       tcp_v6_err,
1901         .flags          =       INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
1902 };
1903
1904 static struct inet_protosw tcpv6_protosw = {
1905         .type           =       SOCK_STREAM,
1906         .protocol       =       IPPROTO_TCP,
1907         .prot           =       &tcpv6_prot,
1908         .ops            =       &inet6_stream_ops,
1909         .flags          =       INET_PROTOSW_PERMANENT |
1910                                 INET_PROTOSW_ICSK,
1911 };
1912
1913 static int __net_init tcpv6_net_init(struct net *net)
1914 {
1915         return inet_ctl_sock_create(&net->ipv6.tcp_sk, PF_INET6,
1916                                     SOCK_RAW, IPPROTO_TCP, net);
1917 }
1918
1919 static void __net_exit tcpv6_net_exit(struct net *net)
1920 {
1921         inet_ctl_sock_destroy(net->ipv6.tcp_sk);
1922 }
1923
1924 static void __net_exit tcpv6_net_exit_batch(struct list_head *net_exit_list)
1925 {
1926         inet_twsk_purge(&tcp_hashinfo, &tcp_death_row, AF_INET6);
1927 }
1928
1929 static struct pernet_operations tcpv6_net_ops = {
1930         .init       = tcpv6_net_init,
1931         .exit       = tcpv6_net_exit,
1932         .exit_batch = tcpv6_net_exit_batch,
1933 };
1934
1935 int __init tcpv6_init(void)
1936 {
1937         int ret;
1938
1939         ret = inet6_add_protocol(&tcpv6_protocol, IPPROTO_TCP);
1940         if (ret)
1941                 goto out;
1942
1943         /* register inet6 protocol */
1944         ret = inet6_register_protosw(&tcpv6_protosw);
1945         if (ret)
1946                 goto out_tcpv6_protocol;
1947
1948         ret = register_pernet_subsys(&tcpv6_net_ops);
1949         if (ret)
1950                 goto out_tcpv6_protosw;
1951 out:
1952         return ret;
1953
1954 out_tcpv6_protosw:
1955         inet6_unregister_protosw(&tcpv6_protosw);
1956 out_tcpv6_protocol:
1957         inet6_del_protocol(&tcpv6_protocol, IPPROTO_TCP);
1958         goto out;
1959 }
1960
1961 void tcpv6_exit(void)
1962 {
1963         unregister_pernet_subsys(&tcpv6_net_ops);
1964         inet6_unregister_protosw(&tcpv6_protosw);
1965         inet6_del_protocol(&tcpv6_protocol, IPPROTO_TCP);
1966 }