net/ipv6/tcp_ipv6.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *      TCP over IPv6
   4  *      Linux INET6 implementation
   5  *
   6  *      Authors:
   7  *      Pedro Roque             <roque@di.fc.ul.pt>
   8  *
   9  *      Based on:
  10  *      linux/net/ipv4/tcp.c
  11  *      linux/net/ipv4/tcp_input.c
  12  *      linux/net/ipv4/tcp_output.c
  13  *
  14  *      Fixes:
  15  *      Hideaki YOSHIFUJI       :       sin6_scope_id support
  16  *      YOSHIFUJI Hideaki @USAGI and:   Support IPV6_V6ONLY socket option, which
  17  *      Alexey Kuznetsov                allow both IPv4 and IPv6 sockets to bind
  18  *                                      a single port at the same time.
  19  *      YOSHIFUJI Hideaki @USAGI:       convert /proc/net/tcp6 to seq_file.
  20  */
  21
  22 #include <linux/bottom_half.h>
  23 #include <linux/module.h>
  24 #include <linux/errno.h>
  25 #include <linux/types.h>
  26 #include <linux/socket.h>
  27 #include <linux/sockios.h>
  28 #include <linux/net.h>
  29 #include <linux/jiffies.h>
  30 #include <linux/in.h>
  31 #include <linux/in6.h>
  32 #include <linux/netdevice.h>
  33 #include <linux/init.h>
  34 #include <linux/jhash.h>
  35 #include <linux/ipsec.h>
  36 #include <linux/times.h>
  37 #include <linux/slab.h>
  38 #include <linux/uaccess.h>
  39 #include <linux/ipv6.h>
  40 #include <linux/icmpv6.h>
  41 #include <linux/random.h>
  42 #include <linux/indirect_call_wrapper.h>
  43
  44 #include <net/tcp.h>
  45 #include <net/ndisc.h>
  46 #include <net/inet6_hashtables.h>
  47 #include <net/inet6_connection_sock.h>
  48 #include <net/ipv6.h>
  49 #include <net/transp_v6.h>
  50 #include <net/addrconf.h>
  51 #include <net/ip6_route.h>
  52 #include <net/ip6_checksum.h>
  53 #include <net/inet_ecn.h>
  54 #include <net/protocol.h>
  55 #include <net/xfrm.h>
  56 #include <net/snmp.h>
  57 #include <net/dsfield.h>
  58 #include <net/timewait_sock.h>
  59 #include <net/inet_common.h>
  60 #include <net/secure_seq.h>
  61 #include <net/busy_poll.h>
  62
  63 #include <linux/proc_fs.h>
  64 #include <linux/seq_file.h>
  65
  66 #include <crypto/hash.h>
  67 #include <linux/scatterlist.h>
  68
  69 #include <trace/events/tcp.h>
  70
  71 static void     tcp_v6_send_reset(const struct sock *sk, struct sk_buff *skb);
  72 static void     tcp_v6_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb,
  73                                       struct request_sock *req);
  74
  75 static int      tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb);
  76
  77 static const struct inet_connection_sock_af_ops ipv6_mapped;
  78 static const struct inet_connection_sock_af_ops ipv6_specific;
  79 #ifdef CONFIG_TCP_MD5SIG
  80 static const struct tcp_sock_af_ops tcp_sock_ipv6_specific;
  81 static const struct tcp_sock_af_ops tcp_sock_ipv6_mapped_specific;
  82 #else
  83 static struct tcp_md5sig_key *tcp_v6_md5_do_lookup(const struct sock *sk,
  84                                                    const struct in6_addr *addr)
  85 {
  86         return NULL;
  87 }
  88 #endif
  89
  90 /* Helper returning the inet6 address from a given tcp socket.
  91  * It can be used in TCP stack instead of inet6_sk(sk).
  92  * This avoids a dereference and allow compiler optimizations.
  93  * It is a specialized version of inet6_sk_generic().
  94  */
  95 static struct ipv6_pinfo *tcp_inet6_sk(const struct sock *sk)
  96 {
  97         unsigned int offset = sizeof(struct tcp6_sock) - sizeof(struct ipv6_pinfo);
  98
  99         return (struct ipv6_pinfo *)(((u8 *)sk) + offset);
 100 }
 101
 102 static void inet6_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb)
 103 {
 104         struct dst_entry *dst = skb_dst(skb);
 105
 106         if (dst && dst_hold_safe(dst)) {
 107                 const struct rt6_info *rt = (const struct rt6_info *)dst;
 108
 109                 sk->sk_rx_dst = dst;
 110                 inet_sk(sk)->rx_dst_ifindex = skb->skb_iif;
 111                 tcp_inet6_sk(sk)->rx_dst_cookie = rt6_get_cookie(rt);
 112         }
 113 }
 114
 115 static u32 tcp_v6_init_seq(const struct sk_buff *skb)
 116 {
 117         return secure_tcpv6_seq(ipv6_hdr(skb)->daddr.s6_addr32,
 118                                 ipv6_hdr(skb)->saddr.s6_addr32,
 119                                 tcp_hdr(skb)->dest,
 120                                 tcp_hdr(skb)->source);
 121 }
 122
 123 static u32 tcp_v6_init_ts_off(const struct net *net, const struct sk_buff *skb)
 124 {
 125         return secure_tcpv6_ts_off(net, ipv6_hdr(skb)->daddr.s6_addr32,
 126                                    ipv6_hdr(skb)->saddr.s6_addr32);
 127 }
 128
 129 static int tcp_v6_pre_connect(struct sock *sk, struct sockaddr *uaddr,
 130                               int addr_len)
 131 {
 132         /* This check is replicated from tcp_v6_connect() and intended to
 133          * prevent BPF program called below from accessing bytes that are out
 134          * of the bound specified by user in addr_len.
 135          */
 136         if (addr_len < SIN6_LEN_RFC2133)
 137                 return -EINVAL;
 138
 139         sock_owned_by_me(sk);
 140
 141         return BPF_CGROUP_RUN_PROG_INET6_CONNECT(sk, uaddr);
 142 }
 143
 144 static int tcp_v6_connect(struct sock *sk, struct sockaddr *uaddr,
 145                           int addr_len)
 146 {
 147         struct sockaddr_in6 *usin = (struct sockaddr_in6 *) uaddr;
 148         struct inet_sock *inet = inet_sk(sk);
 149         struct inet_connection_sock *icsk = inet_csk(sk);
 150         struct ipv6_pinfo *np = tcp_inet6_sk(sk);
 151         struct tcp_sock *tp = tcp_sk(sk);
 152         struct in6_addr *saddr = NULL, *final_p, final;
 153         struct ipv6_txoptions *opt;
 154         struct flowi6 fl6;
 155         struct dst_entry *dst;
 156         int addr_type;
 157         int err;
 158         struct inet_timewait_death_row *tcp_death_row = &sock_net(sk)->ipv4.tcp_death_row;
 159
 160         if (addr_len < SIN6_LEN_RFC2133)
 161                 return -EINVAL;
 162
 163         if (usin->sin6_family != AF_INET6)
 164                 return -EAFNOSUPPORT;
 165
 166         memset(&fl6, 0, sizeof(fl6));
 167
 168         if (np->sndflow) {
 169                 fl6.flowlabel = usin->sin6_flowinfo&IPV6_FLOWINFO_MASK;
 170                 IP6_ECN_flow_init(fl6.flowlabel);
 171                 if (fl6.flowlabel&IPV6_FLOWLABEL_MASK) {
 172                         struct ip6_flowlabel *flowlabel;
 173                         flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
 174                         if (IS_ERR(flowlabel))
 175                                 return -EINVAL;
 176                         fl6_sock_release(flowlabel);
 177                 }
 178         }
 179
 180         /*
 181          *      connect() to INADDR_ANY means loopback (BSD'ism).
 182          */
 183
 184         if (ipv6_addr_any(&usin->sin6_addr)) {
 185                 if (ipv6_addr_v4mapped(&sk->sk_v6_rcv_saddr))
 186                         ipv6_addr_set_v4mapped(htonl(INADDR_LOOPBACK),
 187                                                &usin->sin6_addr);
 188                 else
 189                         usin->sin6_addr = in6addr_loopback;
 190         }
 191
 192         addr_type = ipv6_addr_type(&usin->sin6_addr);
 193
 194         if (addr_type & IPV6_ADDR_MULTICAST)
 195                 return -ENETUNREACH;
 196
 197         if (addr_type&IPV6_ADDR_LINKLOCAL) {
 198                 if (addr_len >= sizeof(struct sockaddr_in6) &&
 199                     usin->sin6_scope_id) {
 200                         /* If interface is set while binding, indices
 201                          * must coincide.
 202                          */
 203                         if (!sk_dev_equal_l3scope(sk, usin->sin6_scope_id))
 204                                 return -EINVAL;
 205
 206                         sk->sk_bound_dev_if = usin->sin6_scope_id;
 207                 }
 208
 209                 /* Connect to link-local address requires an interface */
 210                 if (!sk->sk_bound_dev_if)
 211                         return -EINVAL;
 212         }
 213
 214         if (tp->rx_opt.ts_recent_stamp &&
 215             !ipv6_addr_equal(&sk->sk_v6_daddr, &usin->sin6_addr)) {
 216                 tp->rx_opt.ts_recent = 0;
 217                 tp->rx_opt.ts_recent_stamp = 0;
 218                 WRITE_ONCE(tp->write_seq, 0);
 219         }
 220
 221         sk->sk_v6_daddr = usin->sin6_addr;
 222         np->flow_label = fl6.flowlabel;
 223
 224         /*
 225          *      TCP over IPv4
 226          */
 227
 228         if (addr_type & IPV6_ADDR_MAPPED) {
 229                 u32 exthdrlen = icsk->icsk_ext_hdr_len;
 230                 struct sockaddr_in sin;
 231
 232                 if (__ipv6_only_sock(sk))
 233                         return -ENETUNREACH;
 234
 235                 sin.sin_family = AF_INET;
 236                 sin.sin_port = usin->sin6_port;
 237                 sin.sin_addr.s_addr = usin->sin6_addr.s6_addr32[3];
 238
 239                 icsk->icsk_af_ops = &ipv6_mapped;
 240                 sk->sk_backlog_rcv = tcp_v4_do_rcv;
 241 #ifdef CONFIG_TCP_MD5SIG
 242                 tp->af_specific = &tcp_sock_ipv6_mapped_specific;
 243 #endif
 244
 245                 err = tcp_v4_connect(sk, (struct sockaddr *)&sin, sizeof(sin));
 246
 247                 if (err) {
 248                         icsk->icsk_ext_hdr_len = exthdrlen;
 249                         icsk->icsk_af_ops = &ipv6_specific;
 250                         sk->sk_backlog_rcv = tcp_v6_do_rcv;
 251 #ifdef CONFIG_TCP_MD5SIG
 252                         tp->af_specific = &tcp_sock_ipv6_specific;
 253 #endif
 254                         goto failure;
 255                 }
 256                 np->saddr = sk->sk_v6_rcv_saddr;
 257
 258                 return err;
 259         }
 260
 261         if (!ipv6_addr_any(&sk->sk_v6_rcv_saddr))
 262                 saddr = &sk->sk_v6_rcv_saddr;
 263
 264         fl6.flowi6_proto = IPPROTO_TCP;
 265         fl6.daddr = sk->sk_v6_daddr;
 266         fl6.saddr = saddr ? *saddr : np->saddr;
 267         fl6.flowi6_oif = sk->sk_bound_dev_if;
 268         fl6.flowi6_mark = sk->sk_mark;
 269         fl6.fl6_dport = usin->sin6_port;
 270         fl6.fl6_sport = inet->inet_sport;
 271         fl6.flowi6_uid = sk->sk_uid;
 272
 273         opt = rcu_dereference_protected(np->opt, lockdep_sock_is_held(sk));
 274         final_p = fl6_update_dst(&fl6, opt, &final);
 275
 276         security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));
 277
 278         dst = ip6_dst_lookup_flow(sk, &fl6, final_p);
 279         if (IS_ERR(dst)) {
 280                 err = PTR_ERR(dst);
 281                 goto failure;
 282         }
 283
 284         if (!saddr) {
 285                 saddr = &fl6.saddr;
 286                 sk->sk_v6_rcv_saddr = *saddr;
 287         }
 288
 289         /* set the source address */
 290         np->saddr = *saddr;
 291         inet->inet_rcv_saddr = LOOPBACK4_IPV6;
 292
 293         sk->sk_gso_type = SKB_GSO_TCPV6;
 294         ip6_dst_store(sk, dst, NULL, NULL);
 295
 296         icsk->icsk_ext_hdr_len = 0;
 297         if (opt)
 298                 icsk->icsk_ext_hdr_len = opt->opt_flen +
 299                                          opt->opt_nflen;
 300
 301         tp->rx_opt.mss_clamp = IPV6_MIN_MTU - sizeof(struct tcphdr) - sizeof(struct ipv6hdr);
 302
 303         inet->inet_dport = usin->sin6_port;
 304
 305         tcp_set_state(sk, TCP_SYN_SENT);
 306         err = inet6_hash_connect(tcp_death_row, sk);
 307         if (err)
 308                 goto late_failure;
 309
 310         sk_set_txhash(sk);
 311
 312         if (likely(!tp->repair)) {
 313                 if (!tp->write_seq)
 314                         WRITE_ONCE(tp->write_seq,
 315                                    secure_tcpv6_seq(np->saddr.s6_addr32,
 316                                                     sk->sk_v6_daddr.s6_addr32,
 317                                                     inet->inet_sport,
 318                                                     inet->inet_dport));
 319                 tp->tsoffset = secure_tcpv6_ts_off(sock_net(sk),
 320                                                    np->saddr.s6_addr32,
 321                                                    sk->sk_v6_daddr.s6_addr32);
 322         }
 323
 324         if (tcp_fastopen_defer_connect(sk, &err))
 325                 return err;
 326         if (err)
 327                 goto late_failure;
 328
 329         err = tcp_connect(sk);
 330         if (err)
 331                 goto late_failure;
 332
 333         return 0;
 334
 335 late_failure:
 336         tcp_set_state(sk, TCP_CLOSE);
 337 failure:
 338         inet->inet_dport = 0;
 339         sk->sk_route_caps = 0;
 340         return err;
 341 }
 342
 343 static void tcp_v6_mtu_reduced(struct sock *sk)
 344 {
 345         struct dst_entry *dst;
 346
 347         if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE))
 348                 return;
 349
 350         dst = inet6_csk_update_pmtu(sk, tcp_sk(sk)->mtu_info);
 351         if (!dst)
 352                 return;
 353
 354         if (inet_csk(sk)->icsk_pmtu_cookie > dst_mtu(dst)) {
 355                 tcp_sync_mss(sk, dst_mtu(dst));
 356                 tcp_simple_retransmit(sk);
 357         }
 358 }
 359
 360 static int tcp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 361                 u8 type, u8 code, int offset, __be32 info)
 362 {
 363         const struct ipv6hdr *hdr = (const struct ipv6hdr *)skb->data;
 364         const struct tcphdr *th = (struct tcphdr *)(skb->data+offset);
 365         struct net *net = dev_net(skb->dev);
 366         struct request_sock *fastopen;
 367         struct ipv6_pinfo *np;
 368         struct tcp_sock *tp;
 369         __u32 seq, snd_una;
 370         struct sock *sk;
 371         bool fatal;
 372         int err;
 373
 374         sk = __inet6_lookup_established(net, &tcp_hashinfo,
 375                                         &hdr->daddr, th->dest,
 376                                         &hdr->saddr, ntohs(th->source),
 377                                         skb->dev->ifindex, inet6_sdif(skb));
 378
 379         if (!sk) {
 380                 __ICMP6_INC_STATS(net, __in6_dev_get(skb->dev),
 381                                   ICMP6_MIB_INERRORS);
 382                 return -ENOENT;
 383         }
 384
 385         if (sk->sk_state == TCP_TIME_WAIT) {
 386                 inet_twsk_put(inet_twsk(sk));
 387                 return 0;
 388         }
 389         seq = ntohl(th->seq);
 390         fatal = icmpv6_err_convert(type, code, &err);
 391         if (sk->sk_state == TCP_NEW_SYN_RECV) {
 392                 tcp_req_err(sk, seq, fatal);
 393                 return 0;
 394         }
 395
 396         bh_lock_sock(sk);
 397         if (sock_owned_by_user(sk) && type != ICMPV6_PKT_TOOBIG)
 398                 __NET_INC_STATS(net, LINUX_MIB_LOCKDROPPEDICMPS);
 399
 400         if (sk->sk_state == TCP_CLOSE)
 401                 goto out;
 402
 403         if (ipv6_hdr(skb)->hop_limit < tcp_inet6_sk(sk)->min_hopcount) {
 404                 __NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP);
 405                 goto out;
 406         }
 407
 408         tp = tcp_sk(sk);
 409         /* XXX (TFO) - tp->snd_una should be ISN (tcp_create_openreq_child() */
 410         fastopen = rcu_dereference(tp->fastopen_rsk);
 411         snd_una = fastopen ? tcp_rsk(fastopen)->snt_isn : tp->snd_una;
 412         if (sk->sk_state != TCP_LISTEN &&
 413             !between(seq, snd_una, tp->snd_nxt)) {
 414                 __NET_INC_STATS(net, LINUX_MIB_OUTOFWINDOWICMPS);
 415                 goto out;
 416         }
 417
 418         np = tcp_inet6_sk(sk);
 419
 420         if (type == NDISC_REDIRECT) {
 421                 if (!sock_owned_by_user(sk)) {
 422                         struct dst_entry *dst = __sk_dst_check(sk, np->dst_cookie);
 423
 424                         if (dst)
 425                                 dst->ops->redirect(dst, sk, skb);
 426                 }
 427                 goto out;
 428         }
 429
 430         if (type == ICMPV6_PKT_TOOBIG) {
 431                 /* We are not interested in TCP_LISTEN and open_requests
 432                  * (SYN-ACKs send out by Linux are always <576bytes so
 433                  * they should go through unfragmented).
 434                  */
 435                 if (sk->sk_state == TCP_LISTEN)
 436                         goto out;
 437
 438                 if (!ip6_sk_accept_pmtu(sk))
 439                         goto out;
 440
 441                 tp->mtu_info = ntohl(info);
 442                 if (!sock_owned_by_user(sk))
 443                         tcp_v6_mtu_reduced(sk);
 444                 else if (!test_and_set_bit(TCP_MTU_REDUCED_DEFERRED,
 445                                            &sk->sk_tsq_flags))
 446                         sock_hold(sk);
 447                 goto out;
 448         }
 449
 450
 451         /* Might be for an request_sock */
 452         switch (sk->sk_state) {
 453         case TCP_SYN_SENT:
 454         case TCP_SYN_RECV:
 455                 /* Only in fast or simultaneous open. If a fast open socket is
 456                  * is already accepted it is treated as a connected one below.
 457                  */
 458                 if (fastopen && !fastopen->sk)
 459                         break;
 460
 461                 if (!sock_owned_by_user(sk)) {
 462                         sk->sk_err = err;
 463                         sk->sk_error_report(sk);                /* Wake people up to see the error (see connect in sock.c) */
 464
 465                         tcp_done(sk);
 466                 } else
 467                         sk->sk_err_soft = err;
 468                 goto out;
 469         }
 470
 471         if (!sock_owned_by_user(sk) && np->recverr) {
 472                 sk->sk_err = err;
 473                 sk->sk_error_report(sk);
 474         } else
 475                 sk->sk_err_soft = err;
 476
 477 out:
 478         bh_unlock_sock(sk);
 479         sock_put(sk);
 480         return 0;
 481 }
 482
 483
 484 static int tcp_v6_send_synack(const struct sock *sk, struct dst_entry *dst,
 485                               struct flowi *fl,
 486                               struct request_sock *req,
 487                               struct tcp_fastopen_cookie *foc,
 488                               enum tcp_synack_type synack_type)
 489 {
 490         struct inet_request_sock *ireq = inet_rsk(req);
 491         struct ipv6_pinfo *np = tcp_inet6_sk(sk);
 492         struct ipv6_txoptions *opt;
 493         struct flowi6 *fl6 = &fl->u.ip6;
 494         struct sk_buff *skb;
 495         int err = -ENOMEM;
 496
 497         /* First, grab a route. */
 498         if (!dst && (dst = inet6_csk_route_req(sk, fl6, req,
 499                                                IPPROTO_TCP)) == NULL)
 500                 goto done;
 501
 502         skb = tcp_make_synack(sk, dst, req, foc, synack_type);
 503
 504         if (skb) {
 505                 __tcp_v6_send_check(skb, &ireq->ir_v6_loc_addr,
 506                                     &ireq->ir_v6_rmt_addr);
 507
 508                 fl6->daddr = ireq->ir_v6_rmt_addr;
 509                 if (np->repflow && ireq->pktopts)
 510                         fl6->flowlabel = ip6_flowlabel(ipv6_hdr(ireq->pktopts));
 511
 512                 rcu_read_lock();
 513                 opt = ireq->ipv6_opt;
 514                 if (!opt)
 515                         opt = rcu_dereference(np->opt);
 516                 err = ip6_xmit(sk, skb, fl6, sk->sk_mark, opt, np->tclass,
 517                                sk->sk_priority);
 518                 rcu_read_unlock();
 519                 err = net_xmit_eval(err);
 520         }
 521
 522 done:
 523         return err;
 524 }
 525
 526
 527 static void tcp_v6_reqsk_destructor(struct request_sock *req)
 528 {
 529         kfree(inet_rsk(req)->ipv6_opt);
 530         kfree_skb(inet_rsk(req)->pktopts);
 531 }
 532
 533 #ifdef CONFIG_TCP_MD5SIG
 534 static struct tcp_md5sig_key *tcp_v6_md5_do_lookup(const struct sock *sk,
 535                                                    const struct in6_addr *addr)
 536 {
 537         return tcp_md5_do_lookup(sk, (union tcp_md5_addr *)addr, AF_INET6);
 538 }
 539
 540 static struct tcp_md5sig_key *tcp_v6_md5_lookup(const struct sock *sk,
 541                                                 const struct sock *addr_sk)
 542 {
 543         return tcp_v6_md5_do_lookup(sk, &addr_sk->sk_v6_daddr);
 544 }
 545
 546 static int tcp_v6_parse_md5_keys(struct sock *sk, int optname,
 547                                  char __user *optval, int optlen)
 548 {
 549         struct tcp_md5sig cmd;
 550         struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)&cmd.tcpm_addr;
 551         u8 prefixlen;
 552
 553         if (optlen < sizeof(cmd))
 554                 return -EINVAL;
 555
 556         if (copy_from_user(&cmd, optval, sizeof(cmd)))
 557                 return -EFAULT;
 558
 559         if (sin6->sin6_family != AF_INET6)
 560                 return -EINVAL;
 561
 562         if (optname == TCP_MD5SIG_EXT &&
 563             cmd.tcpm_flags & TCP_MD5SIG_FLAG_PREFIX) {
 564                 prefixlen = cmd.tcpm_prefixlen;
 565                 if (prefixlen > 128 || (ipv6_addr_v4mapped(&sin6->sin6_addr) &&
 566                                         prefixlen > 32))
 567                         return -EINVAL;
 568         } else {
 569                 prefixlen = ipv6_addr_v4mapped(&sin6->sin6_addr) ? 32 : 128;
 570         }
 571
 572         if (!cmd.tcpm_keylen) {
 573                 if (ipv6_addr_v4mapped(&sin6->sin6_addr))
 574                         return tcp_md5_do_del(sk, (union tcp_md5_addr *)&sin6->sin6_addr.s6_addr32[3],
 575                                               AF_INET, prefixlen);
 576                 return tcp_md5_do_del(sk, (union tcp_md5_addr *)&sin6->sin6_addr,
 577                                       AF_INET6, prefixlen);
 578         }
 579
 580         if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN)
 581                 return -EINVAL;
 582
 583         if (ipv6_addr_v4mapped(&sin6->sin6_addr))
 584                 return tcp_md5_do_add(sk, (union tcp_md5_addr *)&sin6->sin6_addr.s6_addr32[3],
 585                                       AF_INET, prefixlen, cmd.tcpm_key,
 586                                       cmd.tcpm_keylen, GFP_KERNEL);
 587
 588         return tcp_md5_do_add(sk, (union tcp_md5_addr *)&sin6->sin6_addr,
 589                               AF_INET6, prefixlen, cmd.tcpm_key,
 590                               cmd.tcpm_keylen, GFP_KERNEL);
 591 }
 592
 593 static int tcp_v6_md5_hash_headers(struct tcp_md5sig_pool *hp,
 594                                    const struct in6_addr *daddr,
 595                                    const struct in6_addr *saddr,
 596                                    const struct tcphdr *th, int nbytes)
 597 {
 598         struct tcp6_pseudohdr *bp;
 599         struct scatterlist sg;
 600         struct tcphdr *_th;
 601
 602         bp = hp->scratch;
 603         /* 1. TCP pseudo-header (RFC2460) */
 604         bp->saddr = *saddr;
 605         bp->daddr = *daddr;
 606         bp->protocol = cpu_to_be32(IPPROTO_TCP);
 607         bp->len = cpu_to_be32(nbytes);
 608
 609         _th = (struct tcphdr *)(bp + 1);
 610         memcpy(_th, th, sizeof(*th));
 611         _th->check = 0;
 612
 613         sg_init_one(&sg, bp, sizeof(*bp) + sizeof(*th));
 614         ahash_request_set_crypt(hp->md5_req, &sg, NULL,
 615                                 sizeof(*bp) + sizeof(*th));
 616         return crypto_ahash_update(hp->md5_req);
 617 }
 618
 619 static int tcp_v6_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key,
 620                                const struct in6_addr *daddr, struct in6_addr *saddr,
 621                                const struct tcphdr *th)
 622 {
 623         struct tcp_md5sig_pool *hp;
 624         struct ahash_request *req;
 625
 626         hp = tcp_get_md5sig_pool();
 627         if (!hp)
 628                 goto clear_hash_noput;
 629         req = hp->md5_req;
 630
 631         if (crypto_ahash_init(req))
 632                 goto clear_hash;
 633         if (tcp_v6_md5_hash_headers(hp, daddr, saddr, th, th->doff << 2))
 634                 goto clear_hash;
 635         if (tcp_md5_hash_key(hp, key))
 636                 goto clear_hash;
 637         ahash_request_set_crypt(req, NULL, md5_hash, 0);
 638         if (crypto_ahash_final(req))
 639                 goto clear_hash;
 640
 641         tcp_put_md5sig_pool();
 642         return 0;
 643
 644 clear_hash:
 645         tcp_put_md5sig_pool();
 646 clear_hash_noput:
 647         memset(md5_hash, 0, 16);
 648         return 1;
 649 }
 650
 651 static int tcp_v6_md5_hash_skb(char *md5_hash,
 652                                const struct tcp_md5sig_key *key,
 653                                const struct sock *sk,
 654                                const struct sk_buff *skb)
 655 {
 656         const struct in6_addr *saddr, *daddr;
 657         struct tcp_md5sig_pool *hp;
 658         struct ahash_request *req;
 659         const struct tcphdr *th = tcp_hdr(skb);
 660
 661         if (sk) { /* valid for establish/request sockets */
 662                 saddr = &sk->sk_v6_rcv_saddr;
 663                 daddr = &sk->sk_v6_daddr;
 664         } else {
 665                 const struct ipv6hdr *ip6h = ipv6_hdr(skb);
 666                 saddr = &ip6h->saddr;
 667                 daddr = &ip6h->daddr;
 668         }
 669
 670         hp = tcp_get_md5sig_pool();
 671         if (!hp)
 672                 goto clear_hash_noput;
 673         req = hp->md5_req;
 674
 675         if (crypto_ahash_init(req))
 676                 goto clear_hash;
 677
 678         if (tcp_v6_md5_hash_headers(hp, daddr, saddr, th, skb->len))
 679                 goto clear_hash;
 680         if (tcp_md5_hash_skb_data(hp, skb, th->doff << 2))
 681                 goto clear_hash;
 682         if (tcp_md5_hash_key(hp, key))
 683                 goto clear_hash;
 684         ahash_request_set_crypt(req, NULL, md5_hash, 0);
 685         if (crypto_ahash_final(req))
 686                 goto clear_hash;
 687
 688         tcp_put_md5sig_pool();
 689         return 0;
 690
 691 clear_hash:
 692         tcp_put_md5sig_pool();
 693 clear_hash_noput:
 694         memset(md5_hash, 0, 16);
 695         return 1;
 696 }
 697
 698 #endif
 699
 700 static bool tcp_v6_inbound_md5_hash(const struct sock *sk,
 701                                     const struct sk_buff *skb)
 702 {
 703 #ifdef CONFIG_TCP_MD5SIG
 704         const __u8 *hash_location = NULL;
 705         struct tcp_md5sig_key *hash_expected;
 706         const struct ipv6hdr *ip6h = ipv6_hdr(skb);
 707         const struct tcphdr *th = tcp_hdr(skb);
 708         int genhash;
 709         u8 newhash[16];
 710
 711         hash_expected = tcp_v6_md5_do_lookup(sk, &ip6h->saddr);
 712         hash_location = tcp_parse_md5sig_option(th);
 713
 714         /* We've parsed the options - do we have a hash? */
 715         if (!hash_expected && !hash_location)
 716                 return false;
 717
 718         if (hash_expected && !hash_location) {
 719                 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5NOTFOUND);
 720                 return true;
 721         }
 722
 723         if (!hash_expected && hash_location) {
 724                 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5UNEXPECTED);
 725                 return true;
 726         }
 727
 728         /* check the signature */
 729         genhash = tcp_v6_md5_hash_skb(newhash,
 730                                       hash_expected,
 731                                       NULL, skb);
 732
 733         if (genhash || memcmp(hash_location, newhash, 16) != 0) {
 734                 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5FAILURE);
 735                 net_info_ratelimited("MD5 Hash %s for [%pI6c]:%u->[%pI6c]:%u\n",
 736                                      genhash ? "failed" : "mismatch",
 737                                      &ip6h->saddr, ntohs(th->source),
 738                                      &ip6h->daddr, ntohs(th->dest));
 739                 return true;
 740         }
 741 #endif
 742         return false;
 743 }
 744
 745 static void tcp_v6_init_req(struct request_sock *req,
 746                             const struct sock *sk_listener,
 747                             struct sk_buff *skb)
 748 {
 749         bool l3_slave = ipv6_l3mdev_skb(TCP_SKB_CB(skb)->header.h6.flags);
 750         struct inet_request_sock *ireq = inet_rsk(req);
 751         const struct ipv6_pinfo *np = tcp_inet6_sk(sk_listener);
 752
 753         ireq->ir_v6_rmt_addr = ipv6_hdr(skb)->saddr;
 754         ireq->ir_v6_loc_addr = ipv6_hdr(skb)->daddr;
 755
 756         /* So that link locals have meaning */
 757         if ((!sk_listener->sk_bound_dev_if || l3_slave) &&
 758             ipv6_addr_type(&ireq->ir_v6_rmt_addr) & IPV6_ADDR_LINKLOCAL)
 759                 ireq->ir_iif = tcp_v6_iif(skb);
 760
 761         if (!TCP_SKB_CB(skb)->tcp_tw_isn &&
 762             (ipv6_opt_accepted(sk_listener, skb, &TCP_SKB_CB(skb)->header.h6) ||
 763              np->rxopt.bits.rxinfo ||
 764              np->rxopt.bits.rxoinfo || np->rxopt.bits.rxhlim ||
 765              np->rxopt.bits.rxohlim || np->repflow)) {
 766                 refcount_inc(&skb->users);
 767                 ireq->pktopts = skb;
 768         }
 769 }
 770
 771 static struct dst_entry *tcp_v6_route_req(const struct sock *sk,
 772                                           struct flowi *fl,
 773                                           const struct request_sock *req)
 774 {
 775         return inet6_csk_route_req(sk, &fl->u.ip6, req, IPPROTO_TCP);
 776 }
 777
 778 struct request_sock_ops tcp6_request_sock_ops __read_mostly = {
 779         .family         =       AF_INET6,
 780         .obj_size       =       sizeof(struct tcp6_request_sock),
 781         .rtx_syn_ack    =       tcp_rtx_synack,
 782         .send_ack       =       tcp_v6_reqsk_send_ack,
 783         .destructor     =       tcp_v6_reqsk_destructor,
 784         .send_reset     =       tcp_v6_send_reset,
 785         .syn_ack_timeout =      tcp_syn_ack_timeout,
 786 };
 787
 788 static const struct tcp_request_sock_ops tcp_request_sock_ipv6_ops = {
 789         .mss_clamp      =       IPV6_MIN_MTU - sizeof(struct tcphdr) -
 790                                 sizeof(struct ipv6hdr),
 791 #ifdef CONFIG_TCP_MD5SIG
 792         .req_md5_lookup =       tcp_v6_md5_lookup,
 793         .calc_md5_hash  =       tcp_v6_md5_hash_skb,
 794 #endif
 795         .init_req       =       tcp_v6_init_req,
 796 #ifdef CONFIG_SYN_COOKIES
 797         .cookie_init_seq =      cookie_v6_init_sequence,
 798 #endif
 799         .route_req      =       tcp_v6_route_req,
 800         .init_seq       =       tcp_v6_init_seq,
 801         .init_ts_off    =       tcp_v6_init_ts_off,
 802         .send_synack    =       tcp_v6_send_synack,
 803 };
 804
 805 static void tcp_v6_send_response(const struct sock *sk, struct sk_buff *skb, u32 seq,
 806                                  u32 ack, u32 win, u32 tsval, u32 tsecr,
 807                                  int oif, struct tcp_md5sig_key *key, int rst,
 808                                  u8 tclass, __be32 label, u32 priority)
 809 {
 810         const struct tcphdr *th = tcp_hdr(skb);
 811         struct tcphdr *t1;
 812         struct sk_buff *buff;
 813         struct flowi6 fl6;
 814         struct net *net = sk ? sock_net(sk) : dev_net(skb_dst(skb)->dev);
 815         struct sock *ctl_sk = net->ipv6.tcp_sk;
 816         unsigned int tot_len = sizeof(struct tcphdr);
 817         struct dst_entry *dst;
 818         __be32 *topt;
 819         __u32 mark = 0;
 820
 821         if (tsecr)
 822                 tot_len += TCPOLEN_TSTAMP_ALIGNED;
 823 #ifdef CONFIG_TCP_MD5SIG
 824         if (key)
 825                 tot_len += TCPOLEN_MD5SIG_ALIGNED;
 826 #endif
 827
 828         buff = alloc_skb(MAX_HEADER + sizeof(struct ipv6hdr) + tot_len,
 829                          GFP_ATOMIC);
 830         if (!buff)
 831                 return;
 832
 833         skb_reserve(buff, MAX_HEADER + sizeof(struct ipv6hdr) + tot_len);
 834
 835         t1 = skb_push(buff, tot_len);
 836         skb_reset_transport_header(buff);
 837
 838         /* Swap the send and the receive. */
 839         memset(t1, 0, sizeof(*t1));
 840         t1->dest = th->source;
 841         t1->source = th->dest;
 842         t1->doff = tot_len / 4;
 843         t1->seq = htonl(seq);
 844         t1->ack_seq = htonl(ack);
 845         t1->ack = !rst || !th->ack;
 846         t1->rst = rst;
 847         t1->window = htons(win);
 848
 849         topt = (__be32 *)(t1 + 1);
 850
 851         if (tsecr) {
 852                 *topt++ = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
 853                                 (TCPOPT_TIMESTAMP << 8) | TCPOLEN_TIMESTAMP);
 854                 *topt++ = htonl(tsval);
 855                 *topt++ = htonl(tsecr);
 856         }
 857
 858 #ifdef CONFIG_TCP_MD5SIG
 859         if (key) {
 860                 *topt++ = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
 861                                 (TCPOPT_MD5SIG << 8) | TCPOLEN_MD5SIG);
 862                 tcp_v6_md5_hash_hdr((__u8 *)topt, key,
 863                                     &ipv6_hdr(skb)->saddr,
 864                                     &ipv6_hdr(skb)->daddr, t1);
 865         }
 866 #endif
 867
 868         memset(&fl6, 0, sizeof(fl6));
 869         fl6.daddr = ipv6_hdr(skb)->saddr;
 870         fl6.saddr = ipv6_hdr(skb)->daddr;
 871         fl6.flowlabel = label;
 872
 873         buff->ip_summed = CHECKSUM_PARTIAL;
 874         buff->csum = 0;
 875
 876         __tcp_v6_send_check(buff, &fl6.saddr, &fl6.daddr);
 877
 878         fl6.flowi6_proto = IPPROTO_TCP;
 879         if (rt6_need_strict(&fl6.daddr) && !oif)
 880                 fl6.flowi6_oif = tcp_v6_iif(skb);
 881         else {
 882                 if (!oif && netif_index_is_l3_master(net, skb->skb_iif))
 883                         oif = skb->skb_iif;
 884
 885                 fl6.flowi6_oif = oif;
 886         }
 887
 888         if (sk) {
 889                 if (sk->sk_state == TCP_TIME_WAIT) {
 890                         mark = inet_twsk(sk)->tw_mark;
 891                         /* autoflowlabel relies on buff->hash */
 892                         skb_set_hash(buff, inet_twsk(sk)->tw_txhash,
 893                                      PKT_HASH_TYPE_L4);
 894                 } else {
 895                         mark = sk->sk_mark;
 896                 }
 897                 buff->tstamp = tcp_transmit_time(sk);
 898         }
 899         fl6.flowi6_mark = IP6_REPLY_MARK(net, skb->mark) ?: mark;
 900         fl6.fl6_dport = t1->dest;
 901         fl6.fl6_sport = t1->source;
 902         fl6.flowi6_uid = sock_net_uid(net, sk && sk_fullsock(sk) ? sk : NULL);
 903         security_skb_classify_flow(skb, flowi6_to_flowi(&fl6));
 904
 905         /* Pass a socket to ip6_dst_lookup either it is for RST
 906          * Underlying function will use this to retrieve the network
 907          * namespace
 908          */
 909         dst = ip6_dst_lookup_flow(ctl_sk, &fl6, NULL);
 910         if (!IS_ERR(dst)) {
 911                 skb_dst_set(buff, dst);
 912                 ip6_xmit(ctl_sk, buff, &fl6, fl6.flowi6_mark, NULL, tclass,
 913                          priority);
 914                 TCP_INC_STATS(net, TCP_MIB_OUTSEGS);
 915                 if (rst)
 916                         TCP_INC_STATS(net, TCP_MIB_OUTRSTS);
 917                 return;
 918         }
 919
 920         kfree_skb(buff);
 921 }
 922
 923 static void tcp_v6_send_reset(const struct sock *sk, struct sk_buff *skb)
 924 {
 925         const struct tcphdr *th = tcp_hdr(skb);
 926         struct ipv6hdr *ipv6h = ipv6_hdr(skb);
 927         u32 seq = 0, ack_seq = 0;
 928         struct tcp_md5sig_key *key = NULL;
 929 #ifdef CONFIG_TCP_MD5SIG
 930         const __u8 *hash_location = NULL;
 931         unsigned char newhash[16];
 932         int genhash;
 933         struct sock *sk1 = NULL;
 934 #endif
 935         __be32 label = 0;
 936         u32 priority = 0;
 937         struct net *net;
 938         int oif = 0;
 939
 940         if (th->rst)
 941                 return;
 942
 943         /* If sk not NULL, it means we did a successful lookup and incoming
 944          * route had to be correct. prequeue might have dropped our dst.
 945          */
 946         if (!sk && !ipv6_unicast_destination(skb))
 947                 return;
 948
 949         net = sk ? sock_net(sk) : dev_net(skb_dst(skb)->dev);
 950 #ifdef CONFIG_TCP_MD5SIG
 951         rcu_read_lock();
 952         hash_location = tcp_parse_md5sig_option(th);
 953         if (sk && sk_fullsock(sk)) {
 954                 key = tcp_v6_md5_do_lookup(sk, &ipv6h->saddr);
 955         } else if (hash_location) {
 956                 /*
 957                  * active side is lost. Try to find listening socket through
 958                  * source port, and then find md5 key through listening socket.
 959                  * we are not loose security here:
 960                  * Incoming packet is checked with md5 hash with finding key,
 961                  * no RST generated if md5 hash doesn't match.
 962                  */
 963                 sk1 = inet6_lookup_listener(net,
 964                                            &tcp_hashinfo, NULL, 0,
 965                                            &ipv6h->saddr,
 966                                            th->source, &ipv6h->daddr,
 967                                            ntohs(th->source),
 968                                            tcp_v6_iif_l3_slave(skb),
 969                                            tcp_v6_sdif(skb));
 970                 if (!sk1)
 971                         goto out;
 972
 973                 key = tcp_v6_md5_do_lookup(sk1, &ipv6h->saddr);
 974                 if (!key)
 975                         goto out;
 976
 977                 genhash = tcp_v6_md5_hash_skb(newhash, key, NULL, skb);
 978                 if (genhash || memcmp(hash_location, newhash, 16) != 0)
 979                         goto out;
 980         }
 981 #endif
 982
 983         if (th->ack)
 984                 seq = ntohl(th->ack_seq);
 985         else
 986                 ack_seq = ntohl(th->seq) + th->syn + th->fin + skb->len -
 987                           (th->doff << 2);
 988
 989         if (sk) {
 990                 oif = sk->sk_bound_dev_if;
 991                 if (sk_fullsock(sk)) {
 992                         const struct ipv6_pinfo *np = tcp_inet6_sk(sk);
 993
 994                         trace_tcp_send_reset(sk, skb);
 995                         if (np->repflow)
 996                                 label = ip6_flowlabel(ipv6h);
 997                         priority = sk->sk_priority;
 998                 }
 999                 if (sk->sk_state == TCP_TIME_WAIT) {
1000                         label = cpu_to_be32(inet_twsk(sk)->tw_flowlabel);
1001                         priority = inet_twsk(sk)->tw_priority;
1002                 }
1003         } else {
1004                 if (net->ipv6.sysctl.flowlabel_reflect & FLOWLABEL_REFLECT_TCP_RESET)
1005                         label = ip6_flowlabel(ipv6h);
1006         }
1007
1008         tcp_v6_send_response(sk, skb, seq, ack_seq, 0, 0, 0, oif, key, 1, 0,
1009                              label, priority);
1010
1011 #ifdef CONFIG_TCP_MD5SIG
1012 out:
1013         rcu_read_unlock();
1014 #endif
1015 }
1016
1017 static void tcp_v6_send_ack(const struct sock *sk, struct sk_buff *skb, u32 seq,
1018                             u32 ack, u32 win, u32 tsval, u32 tsecr, int oif,
1019                             struct tcp_md5sig_key *key, u8 tclass,
1020                             __be32 label, u32 priority)
1021 {
1022         tcp_v6_send_response(sk, skb, seq, ack, win, tsval, tsecr, oif, key, 0,
1023                              tclass, label, priority);
1024 }
1025
1026 static void tcp_v6_timewait_ack(struct sock *sk, struct sk_buff *skb)
1027 {
1028         struct inet_timewait_sock *tw = inet_twsk(sk);
1029         struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
1030
1031         tcp_v6_send_ack(sk, skb, tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
1032                         tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
1033                         tcp_time_stamp_raw() + tcptw->tw_ts_offset,
1034                         tcptw->tw_ts_recent, tw->tw_bound_dev_if, tcp_twsk_md5_key(tcptw),
1035                         tw->tw_tclass, cpu_to_be32(tw->tw_flowlabel), tw->tw_priority);
1036
1037         inet_twsk_put(tw);
1038 }
1039
1040 static void tcp_v6_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb,
1041                                   struct request_sock *req)
1042 {
1043         /* sk->sk_state == TCP_LISTEN -> for regular TCP_SYN_RECV
1044          * sk->sk_state == TCP_SYN_RECV -> for Fast Open.
1045          */
1046         /* RFC 7323 2.3
1047          * The window field (SEG.WND) of every outgoing segment, with the
1048          * exception of <SYN> segments, MUST be right-shifted by
1049          * Rcv.Wind.Shift bits:
1050          */
1051         tcp_v6_send_ack(sk, skb, (sk->sk_state == TCP_LISTEN) ?
1052                         tcp_rsk(req)->snt_isn + 1 : tcp_sk(sk)->snd_nxt,
1053                         tcp_rsk(req)->rcv_nxt,
1054                         req->rsk_rcv_wnd >> inet_rsk(req)->rcv_wscale,
1055                         tcp_time_stamp_raw() + tcp_rsk(req)->ts_off,
1056                         req->ts_recent, sk->sk_bound_dev_if,
1057                         tcp_v6_md5_do_lookup(sk, &ipv6_hdr(skb)->saddr),
1058                         0, 0, sk->sk_priority);
1059 }
1060
1061
1062 static struct sock *tcp_v6_cookie_check(struct sock *sk, struct sk_buff *skb)
1063 {
1064 #ifdef CONFIG_SYN_COOKIES
1065         const struct tcphdr *th = tcp_hdr(skb);
1066
1067         if (!th->syn)
1068                 sk = cookie_v6_check(sk, skb);
1069 #endif
1070         return sk;
1071 }
1072
1073 u16 tcp_v6_get_syncookie(struct sock *sk, struct ipv6hdr *iph,
1074                          struct tcphdr *th, u32 *cookie)
1075 {
1076         u16 mss = 0;
1077 #ifdef CONFIG_SYN_COOKIES
1078         mss = tcp_get_syncookie_mss(&tcp6_request_sock_ops,
1079                                     &tcp_request_sock_ipv6_ops, sk, th);
1080         if (mss) {
1081                 *cookie = __cookie_v6_init_sequence(iph, th, &mss);
1082                 tcp_synq_overflow(sk);
1083         }
1084 #endif
1085         return mss;
1086 }
1087
1088 static int tcp_v6_conn_request(struct sock *sk, struct sk_buff *skb)
1089 {
1090         if (skb->protocol == htons(ETH_P_IP))
1091                 return tcp_v4_conn_request(sk, skb);
1092
1093         if (!ipv6_unicast_destination(skb))
1094                 goto drop;
1095
1096         return tcp_conn_request(&tcp6_request_sock_ops,
1097                                 &tcp_request_sock_ipv6_ops, sk, skb);
1098
1099 drop:
1100         tcp_listendrop(sk);
1101         return 0; /* don't send reset */
1102 }
1103
1104 static void tcp_v6_restore_cb(struct sk_buff *skb)
1105 {
1106         /* We need to move header back to the beginning if xfrm6_policy_check()
1107          * and tcp_v6_fill_cb() are going to be called again.
1108          * ip6_datagram_recv_specific_ctl() also expects IP6CB to be there.
1109          */
1110         memmove(IP6CB(skb), &TCP_SKB_CB(skb)->header.h6,
1111                 sizeof(struct inet6_skb_parm));
1112 }
1113
1114 static struct sock *tcp_v6_syn_recv_sock(const struct sock *sk, struct sk_buff *skb,
1115                                          struct request_sock *req,
1116                                          struct dst_entry *dst,
1117                                          struct request_sock *req_unhash,
1118                                          bool *own_req)
1119 {
1120         struct inet_request_sock *ireq;
1121         struct ipv6_pinfo *newnp;
1122         const struct ipv6_pinfo *np = tcp_inet6_sk(sk);
1123         struct ipv6_txoptions *opt;
1124         struct inet_sock *newinet;
1125         struct tcp_sock *newtp;
1126         struct sock *newsk;
1127 #ifdef CONFIG_TCP_MD5SIG
1128         struct tcp_md5sig_key *key;
1129 #endif
1130         struct flowi6 fl6;
1131
1132         if (skb->protocol == htons(ETH_P_IP)) {
1133                 /*
1134                  *      v6 mapped
1135                  */
1136
1137                 newsk = tcp_v4_syn_recv_sock(sk, skb, req, dst,
1138                                              req_unhash, own_req);
1139
1140                 if (!newsk)
1141                         return NULL;
1142
1143                 inet_sk(newsk)->pinet6 = tcp_inet6_sk(newsk);
1144
1145                 newinet = inet_sk(newsk);
1146                 newnp = tcp_inet6_sk(newsk);
1147                 newtp = tcp_sk(newsk);
1148
1149                 memcpy(newnp, np, sizeof(struct ipv6_pinfo));
1150
1151                 newnp->saddr = newsk->sk_v6_rcv_saddr;
1152
1153                 inet_csk(newsk)->icsk_af_ops = &ipv6_mapped;
1154                 newsk->sk_backlog_rcv = tcp_v4_do_rcv;
1155 #ifdef CONFIG_TCP_MD5SIG
1156                 newtp->af_specific = &tcp_sock_ipv6_mapped_specific;
1157 #endif
1158
1159                 newnp->ipv6_mc_list = NULL;
1160                 newnp->ipv6_ac_list = NULL;
1161                 newnp->ipv6_fl_list = NULL;
1162                 newnp->pktoptions  = NULL;
1163                 newnp->opt         = NULL;
1164                 newnp->mcast_oif   = inet_iif(skb);
1165                 newnp->mcast_hops  = ip_hdr(skb)->ttl;
1166                 newnp->rcv_flowinfo = 0;
1167                 if (np->repflow)
1168                         newnp->flow_label = 0;
1169
1170                 /*
1171                  * No need to charge this sock to the relevant IPv6 refcnt debug socks count
1172                  * here, tcp_create_openreq_child now does this for us, see the comment in
1173                  * that function for the gory details. -acme
1174                  */
1175
1176                 /* It is tricky place. Until this moment IPv4 tcp
1177                    worked with IPv6 icsk.icsk_af_ops.
1178                    Sync it now.
1179                  */
1180                 tcp_sync_mss(newsk, inet_csk(newsk)->icsk_pmtu_cookie);
1181
1182                 return newsk;
1183         }
1184
1185         ireq = inet_rsk(req);
1186
1187         if (sk_acceptq_is_full(sk))
1188                 goto out_overflow;
1189
1190         if (!dst) {
1191                 dst = inet6_csk_route_req(sk, &fl6, req, IPPROTO_TCP);
1192                 if (!dst)
1193                         goto out;
1194         }
1195
1196         newsk = tcp_create_openreq_child(sk, req, skb);
1197         if (!newsk)
1198                 goto out_nonewsk;
1199
1200         /*
1201          * No need to charge this sock to the relevant IPv6 refcnt debug socks
1202          * count here, tcp_create_openreq_child now does this for us, see the
1203          * comment in that function for the gory details. -acme
1204          */
1205
1206         newsk->sk_gso_type = SKB_GSO_TCPV6;
1207         ip6_dst_store(newsk, dst, NULL, NULL);
1208         inet6_sk_rx_dst_set(newsk, skb);
1209
1210         inet_sk(newsk)->pinet6 = tcp_inet6_sk(newsk);
1211
1212         newtp = tcp_sk(newsk);
1213         newinet = inet_sk(newsk);
1214         newnp = tcp_inet6_sk(newsk);
1215
1216         memcpy(newnp, np, sizeof(struct ipv6_pinfo));
1217
1218         newsk->sk_v6_daddr = ireq->ir_v6_rmt_addr;
1219         newnp->saddr = ireq->ir_v6_loc_addr;
1220         newsk->sk_v6_rcv_saddr = ireq->ir_v6_loc_addr;
1221         newsk->sk_bound_dev_if = ireq->ir_iif;
1222
1223         /* Now IPv6 options...
1224
1225            First: no IPv4 options.
1226          */
1227         newinet->inet_opt = NULL;
1228         newnp->ipv6_mc_list = NULL;
1229         newnp->ipv6_ac_list = NULL;
1230         newnp->ipv6_fl_list = NULL;
1231
1232         /* Clone RX bits */
1233         newnp->rxopt.all = np->rxopt.all;
1234
1235         newnp->pktoptions = NULL;
1236         newnp->opt        = NULL;
1237         newnp->mcast_oif  = tcp_v6_iif(skb);
1238         newnp->mcast_hops = ipv6_hdr(skb)->hop_limit;
1239         newnp->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(skb));
1240         if (np->repflow)
1241                 newnp->flow_label = ip6_flowlabel(ipv6_hdr(skb));
1242
1243         /* Clone native IPv6 options from listening socket (if any)
1244
1245            Yes, keeping reference count would be much more clever,
1246            but we make one more one thing there: reattach optmem
1247            to newsk.
1248          */
1249         opt = ireq->ipv6_opt;
1250         if (!opt)
1251                 opt = rcu_dereference(np->opt);
1252         if (opt) {
1253                 opt = ipv6_dup_options(newsk, opt);
1254                 RCU_INIT_POINTER(newnp->opt, opt);
1255         }
1256         inet_csk(newsk)->icsk_ext_hdr_len = 0;
1257         if (opt)
1258                 inet_csk(newsk)->icsk_ext_hdr_len = opt->opt_nflen +
1259                                                     opt->opt_flen;
1260
1261         tcp_ca_openreq_child(newsk, dst);
1262
1263         tcp_sync_mss(newsk, dst_mtu(dst));
1264         newtp->advmss = tcp_mss_clamp(tcp_sk(sk), dst_metric_advmss(dst));
1265
1266         tcp_initialize_rcv_mss(newsk);
1267
1268         newinet->inet_daddr = newinet->inet_saddr = LOOPBACK4_IPV6;
1269         newinet->inet_rcv_saddr = LOOPBACK4_IPV6;
1270
1271 #ifdef CONFIG_TCP_MD5SIG
1272         /* Copy over the MD5 key from the original socket */
1273         key = tcp_v6_md5_do_lookup(sk, &newsk->sk_v6_daddr);
1274         if (key) {
1275                 /* We're using one, so create a matching key
1276                  * on the newsk structure. If we fail to get
1277                  * memory, then we end up not copying the key
1278                  * across. Shucks.
1279                  */
1280                 tcp_md5_do_add(newsk, (union tcp_md5_addr *)&newsk->sk_v6_daddr,
1281                                AF_INET6, 128, key->key, key->keylen,
1282                                sk_gfp_mask(sk, GFP_ATOMIC));
1283         }
1284 #endif
1285
1286         if (__inet_inherit_port(sk, newsk) < 0) {
1287                 inet_csk_prepare_forced_close(newsk);
1288                 tcp_done(newsk);
1289                 goto out;
1290         }
1291         *own_req = inet_ehash_nolisten(newsk, req_to_sk(req_unhash));
1292         if (*own_req) {
1293                 tcp_move_syn(newtp, req);
1294
1295                 /* Clone pktoptions received with SYN, if we own the req */
1296                 if (ireq->pktopts) {
1297                         newnp->pktoptions = skb_clone(ireq->pktopts,
1298                                                       sk_gfp_mask(sk, GFP_ATOMIC));
1299                         consume_skb(ireq->pktopts);
1300                         ireq->pktopts = NULL;
1301                         if (newnp->pktoptions) {
1302                                 tcp_v6_restore_cb(newnp->pktoptions);
1303                                 skb_set_owner_r(newnp->pktoptions, newsk);
1304                         }
1305                 }
1306         }
1307
1308         return newsk;
1309
1310 out_overflow:
1311         __NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
1312 out_nonewsk:
1313         dst_release(dst);
1314 out:
1315         tcp_listendrop(sk);
1316         return NULL;
1317 }
1318
1319 /* The socket must have it's spinlock held when we get
1320  * here, unless it is a TCP_LISTEN socket.
1321  *
1322  * We have a potential double-lock case here, so even when
1323  * doing backlog processing we use the BH locking scheme.
1324  * This is because we cannot sleep with the original spinlock
1325  * held.
1326  */
1327 static int tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb)
1328 {
1329         struct ipv6_pinfo *np = tcp_inet6_sk(sk);
1330         struct sk_buff *opt_skb = NULL;
1331         struct tcp_sock *tp;
1332
1333         /* Imagine: socket is IPv6. IPv4 packet arrives,
1334            goes to IPv4 receive handler and backlogged.
1335            From backlog it always goes here. Kerboom...
1336            Fortunately, tcp_rcv_established and rcv_established
1337            handle them correctly, but it is not case with
1338            tcp_v6_hnd_req and tcp_v6_send_reset().   --ANK
1339          */
1340
1341         if (skb->protocol == htons(ETH_P_IP))
1342                 return tcp_v4_do_rcv(sk, skb);
1343
1344         /*
1345          *      socket locking is here for SMP purposes as backlog rcv
1346          *      is currently called with bh processing disabled.
1347          */
1348
1349         /* Do Stevens' IPV6_PKTOPTIONS.
1350
1351            Yes, guys, it is the only place in our code, where we
1352            may make it not affecting IPv4.
1353            The rest of code is protocol independent,
1354            and I do not like idea to uglify IPv4.
1355
1356            Actually, all the idea behind IPV6_PKTOPTIONS
1357            looks not very well thought. For now we latch
1358            options, received in the last packet, enqueued
1359            by tcp. Feel free to propose better solution.
1360                                                --ANK (980728)
1361          */
1362         if (np->rxopt.all)
1363                 opt_skb = skb_clone(skb, sk_gfp_mask(sk, GFP_ATOMIC));
1364
1365         if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
1366                 struct dst_entry *dst = sk->sk_rx_dst;
1367
1368                 sock_rps_save_rxhash(sk, skb);
1369                 sk_mark_napi_id(sk, skb);
1370                 if (dst) {
1371                         if (inet_sk(sk)->rx_dst_ifindex != skb->skb_iif ||
1372                             dst->ops->check(dst, np->rx_dst_cookie) == NULL) {
1373                                 dst_release(dst);
1374                                 sk->sk_rx_dst = NULL;
1375                         }
1376                 }
1377
1378                 tcp_rcv_established(sk, skb);
1379                 if (opt_skb)
1380                         goto ipv6_pktoptions;
1381                 return 0;
1382         }
1383
1384         if (tcp_checksum_complete(skb))
1385                 goto csum_err;
1386
1387         if (sk->sk_state == TCP_LISTEN) {
1388                 struct sock *nsk = tcp_v6_cookie_check(sk, skb);
1389
1390                 if (!nsk)
1391                         goto discard;
1392
1393                 if (nsk != sk) {
1394                         if (tcp_child_process(sk, nsk, skb))
1395                                 goto reset;
1396                         if (opt_skb)
1397                                 __kfree_skb(opt_skb);
1398                         return 0;
1399                 }
1400         } else
1401                 sock_rps_save_rxhash(sk, skb);
1402
1403         if (tcp_rcv_state_process(sk, skb))
1404                 goto reset;
1405         if (opt_skb)
1406                 goto ipv6_pktoptions;
1407         return 0;
1408
1409 reset:
1410         tcp_v6_send_reset(sk, skb);
1411 discard:
1412         if (opt_skb)
1413                 __kfree_skb(opt_skb);
1414         kfree_skb(skb);
1415         return 0;
1416 csum_err:
1417         TCP_INC_STATS(sock_net(sk), TCP_MIB_CSUMERRORS);
1418         TCP_INC_STATS(sock_net(sk), TCP_MIB_INERRS);
1419         goto discard;
1420
1421
1422 ipv6_pktoptions:
1423         /* Do you ask, what is it?
1424
1425            1. skb was enqueued by tcp.
1426            2. skb is added to tail of read queue, rather than out of order.
1427            3. socket is not in passive state.
1428            4. Finally, it really contains options, which user wants to receive.
1429          */
1430         tp = tcp_sk(sk);
1431         if (TCP_SKB_CB(opt_skb)->end_seq == tp->rcv_nxt &&
1432             !((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN))) {
1433                 if (np->rxopt.bits.rxinfo || np->rxopt.bits.rxoinfo)
1434                         np->mcast_oif = tcp_v6_iif(opt_skb);
1435                 if (np->rxopt.bits.rxhlim || np->rxopt.bits.rxohlim)
1436                         np->mcast_hops = ipv6_hdr(opt_skb)->hop_limit;
1437                 if (np->rxopt.bits.rxflow || np->rxopt.bits.rxtclass)
1438                         np->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(opt_skb));
1439                 if (np->repflow)
1440                         np->flow_label = ip6_flowlabel(ipv6_hdr(opt_skb));
1441                 if (ipv6_opt_accepted(sk, opt_skb, &TCP_SKB_CB(opt_skb)->header.h6)) {
1442                         skb_set_owner_r(opt_skb, sk);
1443                         tcp_v6_restore_cb(opt_skb);
1444                         opt_skb = xchg(&np->pktoptions, opt_skb);
1445                 } else {
1446                         __kfree_skb(opt_skb);
1447                         opt_skb = xchg(&np->pktoptions, NULL);
1448                 }
1449         }
1450
1451         kfree_skb(opt_skb);
1452         return 0;
1453 }
1454
1455 static void tcp_v6_fill_cb(struct sk_buff *skb, const struct ipv6hdr *hdr,
1456                            const struct tcphdr *th)
1457 {
1458         /* This is tricky: we move IP6CB at its correct location into
1459          * TCP_SKB_CB(). It must be done after xfrm6_policy_check(), because
1460          * _decode_session6() uses IP6CB().
1461          * barrier() makes sure compiler won't play aliasing games.
1462          */
1463         memmove(&TCP_SKB_CB(skb)->header.h6, IP6CB(skb),
1464                 sizeof(struct inet6_skb_parm));
1465         barrier();
1466
1467         TCP_SKB_CB(skb)->seq = ntohl(th->seq);
1468         TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
1469                                     skb->len - th->doff*4);
1470         TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
1471         TCP_SKB_CB(skb)->tcp_flags = tcp_flag_byte(th);
1472         TCP_SKB_CB(skb)->tcp_tw_isn = 0;
1473         TCP_SKB_CB(skb)->ip_dsfield = ipv6_get_dsfield(hdr);
1474         TCP_SKB_CB(skb)->sacked = 0;
1475         TCP_SKB_CB(skb)->has_rxtstamp =
1476                         skb->tstamp || skb_hwtstamps(skb)->hwtstamp;
1477 }
1478
1479 INDIRECT_CALLABLE_SCOPE int tcp_v6_rcv(struct sk_buff *skb)
1480 {
1481         struct sk_buff *skb_to_free;
1482         int sdif = inet6_sdif(skb);
1483         const struct tcphdr *th;
1484         const struct ipv6hdr *hdr;
1485         bool refcounted;
1486         struct sock *sk;
1487         int ret;
1488         struct net *net = dev_net(skb->dev);
1489
1490         if (skb->pkt_type != PACKET_HOST)
1491                 goto discard_it;
1492
1493         /*
1494          *      Count it even if it's bad.
1495          */
1496         __TCP_INC_STATS(net, TCP_MIB_INSEGS);
1497
1498         if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
1499                 goto discard_it;
1500
1501         th = (const struct tcphdr *)skb->data;
1502
1503         if (unlikely(th->doff < sizeof(struct tcphdr)/4))
1504                 goto bad_packet;
1505         if (!pskb_may_pull(skb, th->doff*4))
1506                 goto discard_it;
1507
1508         if (skb_checksum_init(skb, IPPROTO_TCP, ip6_compute_pseudo))
1509                 goto csum_error;
1510
1511         th = (const struct tcphdr *)skb->data;
1512         hdr = ipv6_hdr(skb);
1513
1514 lookup:
1515         sk = __inet6_lookup_skb(&tcp_hashinfo, skb, __tcp_hdrlen(th),
1516                                 th->source, th->dest, inet6_iif(skb), sdif,
1517                                 &refcounted);
1518         if (!sk)
1519                 goto no_tcp_socket;
1520
1521 process:
1522         if (sk->sk_state == TCP_TIME_WAIT)
1523                 goto do_time_wait;
1524
1525         if (sk->sk_state == TCP_NEW_SYN_RECV) {
1526                 struct request_sock *req = inet_reqsk(sk);
1527                 bool req_stolen = false;
1528                 struct sock *nsk;
1529
1530                 sk = req->rsk_listener;
1531                 if (tcp_v6_inbound_md5_hash(sk, skb)) {
1532                         sk_drops_add(sk, skb);
1533                         reqsk_put(req);
1534                         goto discard_it;
1535                 }
1536                 if (tcp_checksum_complete(skb)) {
1537                         reqsk_put(req);
1538                         goto csum_error;
1539                 }
1540                 if (unlikely(sk->sk_state != TCP_LISTEN)) {
1541                         inet_csk_reqsk_queue_drop_and_put(sk, req);
1542                         goto lookup;
1543                 }
1544                 sock_hold(sk);
1545                 refcounted = true;
1546                 nsk = NULL;
1547                 if (!tcp_filter(sk, skb)) {
1548                         th = (const struct tcphdr *)skb->data;
1549                         hdr = ipv6_hdr(skb);
1550                         tcp_v6_fill_cb(skb, hdr, th);
1551                         nsk = tcp_check_req(sk, skb, req, false, &req_stolen);
1552                 }
1553                 if (!nsk) {
1554                         reqsk_put(req);
1555                         if (req_stolen) {
1556                                 /* Another cpu got exclusive access to req
1557                                  * and created a full blown socket.
1558                                  * Try to feed this packet to this socket
1559                                  * instead of discarding it.
1560                                  */
1561                                 tcp_v6_restore_cb(skb);
1562                                 sock_put(sk);
1563                                 goto lookup;
1564                         }
1565                         goto discard_and_relse;
1566                 }
1567                 if (nsk == sk) {
1568                         reqsk_put(req);
1569                         tcp_v6_restore_cb(skb);
1570                 } else if (tcp_child_process(sk, nsk, skb)) {
1571                         tcp_v6_send_reset(nsk, skb);
1572                         goto discard_and_relse;
1573                 } else {
1574                         sock_put(sk);
1575                         return 0;
1576                 }
1577         }
1578         if (hdr->hop_limit < tcp_inet6_sk(sk)->min_hopcount) {
1579                 __NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP);
1580                 goto discard_and_relse;
1581         }
1582
1583         if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb))
1584                 goto discard_and_relse;
1585
1586         if (tcp_v6_inbound_md5_hash(sk, skb))
1587                 goto discard_and_relse;
1588
1589         if (tcp_filter(sk, skb))
1590                 goto discard_and_relse;
1591         th = (const struct tcphdr *)skb->data;
1592         hdr = ipv6_hdr(skb);
1593         tcp_v6_fill_cb(skb, hdr, th);
1594
1595         skb->dev = NULL;
1596
1597         if (sk->sk_state == TCP_LISTEN) {
1598                 ret = tcp_v6_do_rcv(sk, skb);
1599                 goto put_and_return;
1600         }
1601
1602         sk_incoming_cpu_update(sk);
1603
1604         bh_lock_sock_nested(sk);
1605         tcp_segs_in(tcp_sk(sk), skb);
1606         ret = 0;
1607         if (!sock_owned_by_user(sk)) {
1608                 skb_to_free = sk->sk_rx_skb_cache;
1609                 sk->sk_rx_skb_cache = NULL;
1610                 ret = tcp_v6_do_rcv(sk, skb);
1611         } else {
1612                 if (tcp_add_backlog(sk, skb))
1613                         goto discard_and_relse;
1614                 skb_to_free = NULL;
1615         }
1616         bh_unlock_sock(sk);
1617         if (skb_to_free)
1618                 __kfree_skb(skb_to_free);
1619 put_and_return:
1620         if (refcounted)
1621                 sock_put(sk);
1622         return ret ? -1 : 0;
1623
1624 no_tcp_socket:
1625         if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb))
1626                 goto discard_it;
1627
1628         tcp_v6_fill_cb(skb, hdr, th);
1629
1630         if (tcp_checksum_complete(skb)) {
1631 csum_error:
1632                 __TCP_INC_STATS(net, TCP_MIB_CSUMERRORS);
1633 bad_packet:
1634                 __TCP_INC_STATS(net, TCP_MIB_INERRS);
1635         } else {
1636                 tcp_v6_send_reset(NULL, skb);
1637         }
1638
1639 discard_it:
1640         kfree_skb(skb);
1641         return 0;
1642
1643 discard_and_relse:
1644         sk_drops_add(sk, skb);
1645         if (refcounted)
1646                 sock_put(sk);
1647         goto discard_it;
1648
1649 do_time_wait:
1650         if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
1651                 inet_twsk_put(inet_twsk(sk));
1652                 goto discard_it;
1653         }
1654
1655         tcp_v6_fill_cb(skb, hdr, th);
1656
1657         if (tcp_checksum_complete(skb)) {
1658                 inet_twsk_put(inet_twsk(sk));
1659                 goto csum_error;
1660         }
1661
1662         switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) {
1663         case TCP_TW_SYN:
1664         {
1665                 struct sock *sk2;
1666
1667                 sk2 = inet6_lookup_listener(dev_net(skb->dev), &tcp_hashinfo,
1668                                             skb, __tcp_hdrlen(th),
1669                                             &ipv6_hdr(skb)->saddr, th->source,
1670                                             &ipv6_hdr(skb)->daddr,
1671                                             ntohs(th->dest),
1672                                             tcp_v6_iif_l3_slave(skb),
1673                                             sdif);
1674                 if (sk2) {
1675                         struct inet_timewait_sock *tw = inet_twsk(sk);
1676                         inet_twsk_deschedule_put(tw);
1677                         sk = sk2;
1678                         tcp_v6_restore_cb(skb);
1679                         refcounted = false;
1680                         goto process;
1681                 }
1682         }
1683                 /* to ACK */
1684                 /* fall through */
1685         case TCP_TW_ACK:
1686                 tcp_v6_timewait_ack(sk, skb);
1687                 break;
1688         case TCP_TW_RST:
1689                 tcp_v6_send_reset(sk, skb);
1690                 inet_twsk_deschedule_put(inet_twsk(sk));
1691                 goto discard_it;
1692         case TCP_TW_SUCCESS:
1693                 ;
1694         }
1695         goto discard_it;
1696 }
1697
1698 INDIRECT_CALLABLE_SCOPE void tcp_v6_early_demux(struct sk_buff *skb)
1699 {
1700         const struct ipv6hdr *hdr;
1701         const struct tcphdr *th;
1702         struct sock *sk;
1703
1704         if (skb->pkt_type != PACKET_HOST)
1705                 return;
1706
1707         if (!pskb_may_pull(skb, skb_transport_offset(skb) + sizeof(struct tcphdr)))
1708                 return;
1709
1710         hdr = ipv6_hdr(skb);
1711         th = tcp_hdr(skb);
1712
1713         if (th->doff < sizeof(struct tcphdr) / 4)
1714                 return;
1715
1716         /* Note : We use inet6_iif() here, not tcp_v6_iif() */
1717         sk = __inet6_lookup_established(dev_net(skb->dev), &tcp_hashinfo,
1718                                         &hdr->saddr, th->source,
1719                                         &hdr->daddr, ntohs(th->dest),
1720                                         inet6_iif(skb), inet6_sdif(skb));
1721         if (sk) {
1722                 skb->sk = sk;
1723                 skb->destructor = sock_edemux;
1724                 if (sk_fullsock(sk)) {
1725                         struct dst_entry *dst = READ_ONCE(sk->sk_rx_dst);
1726
1727                         if (dst)
1728                                 dst = dst_check(dst, tcp_inet6_sk(sk)->rx_dst_cookie);
1729                         if (dst &&
1730                             inet_sk(sk)->rx_dst_ifindex == skb->skb_iif)
1731                                 skb_dst_set_noref(skb, dst);
1732                 }
1733         }
1734 }
1735
1736 static struct timewait_sock_ops tcp6_timewait_sock_ops = {
1737         .twsk_obj_size  = sizeof(struct tcp6_timewait_sock),
1738         .twsk_unique    = tcp_twsk_unique,
1739         .twsk_destructor = tcp_twsk_destructor,
1740 };
1741
1742 static const struct inet_connection_sock_af_ops ipv6_specific = {
1743         .queue_xmit        = inet6_csk_xmit,
1744         .send_check        = tcp_v6_send_check,
1745         .rebuild_header    = inet6_sk_rebuild_header,
1746         .sk_rx_dst_set     = inet6_sk_rx_dst_set,
1747         .conn_request      = tcp_v6_conn_request,
1748         .syn_recv_sock     = tcp_v6_syn_recv_sock,
1749         .net_header_len    = sizeof(struct ipv6hdr),
1750         .net_frag_header_len = sizeof(struct frag_hdr),
1751         .setsockopt        = ipv6_setsockopt,
1752         .getsockopt        = ipv6_getsockopt,
1753         .addr2sockaddr     = inet6_csk_addr2sockaddr,
1754         .sockaddr_len      = sizeof(struct sockaddr_in6),
1755 #ifdef CONFIG_COMPAT
1756         .compat_setsockopt = compat_ipv6_setsockopt,
1757         .compat_getsockopt = compat_ipv6_getsockopt,
1758 #endif
1759         .mtu_reduced       = tcp_v6_mtu_reduced,
1760 };
1761
1762 #ifdef CONFIG_TCP_MD5SIG
1763 static const struct tcp_sock_af_ops tcp_sock_ipv6_specific = {
1764         .md5_lookup     =       tcp_v6_md5_lookup,
1765         .calc_md5_hash  =       tcp_v6_md5_hash_skb,
1766         .md5_parse      =       tcp_v6_parse_md5_keys,
1767 };
1768 #endif
1769
1770 /*
1771  *      TCP over IPv4 via INET6 API
1772  */
1773 static const struct inet_connection_sock_af_ops ipv6_mapped = {
1774         .queue_xmit        = ip_queue_xmit,
1775         .send_check        = tcp_v4_send_check,
1776         .rebuild_header    = inet_sk_rebuild_header,
1777         .sk_rx_dst_set     = inet_sk_rx_dst_set,
1778         .conn_request      = tcp_v6_conn_request,
1779         .syn_recv_sock     = tcp_v6_syn_recv_sock,
1780         .net_header_len    = sizeof(struct iphdr),
1781         .setsockopt        = ipv6_setsockopt,
1782         .getsockopt        = ipv6_getsockopt,
1783         .addr2sockaddr     = inet6_csk_addr2sockaddr,
1784         .sockaddr_len      = sizeof(struct sockaddr_in6),
1785 #ifdef CONFIG_COMPAT
1786         .compat_setsockopt = compat_ipv6_setsockopt,
1787         .compat_getsockopt = compat_ipv6_getsockopt,
1788 #endif
1789         .mtu_reduced       = tcp_v4_mtu_reduced,
1790 };
1791
1792 #ifdef CONFIG_TCP_MD5SIG
1793 static const struct tcp_sock_af_ops tcp_sock_ipv6_mapped_specific = {
1794         .md5_lookup     =       tcp_v4_md5_lookup,
1795         .calc_md5_hash  =       tcp_v4_md5_hash_skb,
1796         .md5_parse      =       tcp_v6_parse_md5_keys,
1797 };
1798 #endif
1799
1800 /* NOTE: A lot of things set to zero explicitly by call to
1801  *       sk_alloc() so need not be done here.
1802  */
1803 static int tcp_v6_init_sock(struct sock *sk)
1804 {
1805         struct inet_connection_sock *icsk = inet_csk(sk);
1806
1807         tcp_init_sock(sk);
1808
1809         icsk->icsk_af_ops = &ipv6_specific;
1810
1811 #ifdef CONFIG_TCP_MD5SIG
1812         tcp_sk(sk)->af_specific = &tcp_sock_ipv6_specific;
1813 #endif
1814
1815         return 0;
1816 }
1817
1818 static void tcp_v6_destroy_sock(struct sock *sk)
1819 {
1820         tcp_v4_destroy_sock(sk);
1821         inet6_destroy_sock(sk);
1822 }
1823
1824 #ifdef CONFIG_PROC_FS
1825 /* Proc filesystem TCPv6 sock list dumping. */
1826 static void get_openreq6(struct seq_file *seq,
1827                          const struct request_sock *req, int i)
1828 {
1829         long ttd = req->rsk_timer.expires - jiffies;
1830         const struct in6_addr *src = &inet_rsk(req)->ir_v6_loc_addr;
1831         const struct in6_addr *dest = &inet_rsk(req)->ir_v6_rmt_addr;
1832
1833         if (ttd < 0)
1834                 ttd = 0;
1835
1836         seq_printf(seq,
1837                    "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
1838                    "%02X %08X:%08X %02X:%08lX %08X %5u %8d %d %d %pK\n",
1839                    i,
1840                    src->s6_addr32[0], src->s6_addr32[1],
1841                    src->s6_addr32[2], src->s6_addr32[3],
1842                    inet_rsk(req)->ir_num,
1843                    dest->s6_addr32[0], dest->s6_addr32[1],
1844                    dest->s6_addr32[2], dest->s6_addr32[3],
1845                    ntohs(inet_rsk(req)->ir_rmt_port),
1846                    TCP_SYN_RECV,
1847                    0, 0, /* could print option size, but that is af dependent. */
1848                    1,   /* timers active (only the expire timer) */
1849                    jiffies_to_clock_t(ttd),
1850                    req->num_timeout,
1851                    from_kuid_munged(seq_user_ns(seq),
1852                                     sock_i_uid(req->rsk_listener)),
1853                    0,  /* non standard timer */
1854                    0, /* open_requests have no inode */
1855                    0, req);
1856 }
1857
1858 static void get_tcp6_sock(struct seq_file *seq, struct sock *sp, int i)
1859 {
1860         const struct in6_addr *dest, *src;
1861         __u16 destp, srcp;
1862         int timer_active;
1863         unsigned long timer_expires;
1864         const struct inet_sock *inet = inet_sk(sp);
1865         const struct tcp_sock *tp = tcp_sk(sp);
1866         const struct inet_connection_sock *icsk = inet_csk(sp);
1867         const struct fastopen_queue *fastopenq = &icsk->icsk_accept_queue.fastopenq;
1868         int rx_queue;
1869         int state;
1870
1871         dest  = &sp->sk_v6_daddr;
1872         src   = &sp->sk_v6_rcv_saddr;
1873         destp = ntohs(inet->inet_dport);
1874         srcp  = ntohs(inet->inet_sport);
1875
1876         if (icsk->icsk_pending == ICSK_TIME_RETRANS ||
1877             icsk->icsk_pending == ICSK_TIME_REO_TIMEOUT ||
1878             icsk->icsk_pending == ICSK_TIME_LOSS_PROBE) {
1879                 timer_active    = 1;
1880                 timer_expires   = icsk->icsk_timeout;
1881         } else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
1882                 timer_active    = 4;
1883                 timer_expires   = icsk->icsk_timeout;
1884         } else if (timer_pending(&sp->sk_timer)) {
1885                 timer_active    = 2;
1886                 timer_expires   = sp->sk_timer.expires;
1887         } else {
1888                 timer_active    = 0;
1889                 timer_expires = jiffies;
1890         }
1891
1892         state = inet_sk_state_load(sp);
1893         if (state == TCP_LISTEN)
1894                 rx_queue = sp->sk_ack_backlog;
1895         else
1896                 /* Because we don't lock the socket,
1897                  * we might find a transient negative value.
1898                  */
1899                 rx_queue = max_t(int, READ_ONCE(tp->rcv_nxt) -
1900                                       READ_ONCE(tp->copied_seq), 0);
1901
1902         seq_printf(seq,
1903                    "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
1904                    "%02X %08X:%08X %02X:%08lX %08X %5u %8d %lu %d %pK %lu %lu %u %u %d\n",
1905                    i,
1906                    src->s6_addr32[0], src->s6_addr32[1],
1907                    src->s6_addr32[2], src->s6_addr32[3], srcp,
1908                    dest->s6_addr32[0], dest->s6_addr32[1],
1909                    dest->s6_addr32[2], dest->s6_addr32[3], destp,
1910                    state,
1911                    READ_ONCE(tp->write_seq) - tp->snd_una,
1912                    rx_queue,
1913                    timer_active,
1914                    jiffies_delta_to_clock_t(timer_expires - jiffies),
1915                    icsk->icsk_retransmits,
1916                    from_kuid_munged(seq_user_ns(seq), sock_i_uid(sp)),
1917                    icsk->icsk_probes_out,
1918                    sock_i_ino(sp),
1919                    refcount_read(&sp->sk_refcnt), sp,
1920                    jiffies_to_clock_t(icsk->icsk_rto),
1921                    jiffies_to_clock_t(icsk->icsk_ack.ato),
1922                    (icsk->icsk_ack.quick << 1) | inet_csk_in_pingpong_mode(sp),
1923                    tp->snd_cwnd,
1924                    state == TCP_LISTEN ?
1925                         fastopenq->max_qlen :
1926                         (tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh)
1927                    );
1928 }
1929
1930 static void get_timewait6_sock(struct seq_file *seq,
1931                                struct inet_timewait_sock *tw, int i)
1932 {
1933         long delta = tw->tw_timer.expires - jiffies;
1934         const struct in6_addr *dest, *src;
1935         __u16 destp, srcp;
1936
1937         dest = &tw->tw_v6_daddr;
1938         src  = &tw->tw_v6_rcv_saddr;
1939         destp = ntohs(tw->tw_dport);
1940         srcp  = ntohs(tw->tw_sport);
1941
1942         seq_printf(seq,
1943                    "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
1944                    "%02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK\n",
1945                    i,
1946                    src->s6_addr32[0], src->s6_addr32[1],
1947                    src->s6_addr32[2], src->s6_addr32[3], srcp,
1948                    dest->s6_addr32[0], dest->s6_addr32[1],
1949                    dest->s6_addr32[2], dest->s6_addr32[3], destp,
1950                    tw->tw_substate, 0, 0,
1951                    3, jiffies_delta_to_clock_t(delta), 0, 0, 0, 0,
1952                    refcount_read(&tw->tw_refcnt), tw);
1953 }
1954
1955 static int tcp6_seq_show(struct seq_file *seq, void *v)
1956 {
1957         struct tcp_iter_state *st;
1958         struct sock *sk = v;
1959
1960         if (v == SEQ_START_TOKEN) {
1961                 seq_puts(seq,
1962                          "  sl  "
1963                          "local_address                         "
1964                          "remote_address                        "
1965                          "st tx_queue rx_queue tr tm->when retrnsmt"
1966                          "   uid  timeout inode\n");
1967                 goto out;
1968         }
1969         st = seq->private;
1970
1971         if (sk->sk_state == TCP_TIME_WAIT)
1972                 get_timewait6_sock(seq, v, st->num);
1973         else if (sk->sk_state == TCP_NEW_SYN_RECV)
1974                 get_openreq6(seq, v, st->num);
1975         else
1976                 get_tcp6_sock(seq, v, st->num);
1977 out:
1978         return 0;
1979 }
1980
1981 static const struct seq_operations tcp6_seq_ops = {
1982         .show           = tcp6_seq_show,
1983         .start          = tcp_seq_start,
1984         .next           = tcp_seq_next,
1985         .stop           = tcp_seq_stop,
1986 };
1987
1988 static struct tcp_seq_afinfo tcp6_seq_afinfo = {
1989         .family         = AF_INET6,
1990 };
1991
1992 int __net_init tcp6_proc_init(struct net *net)
1993 {
1994         if (!proc_create_net_data("tcp6", 0444, net->proc_net, &tcp6_seq_ops,
1995                         sizeof(struct tcp_iter_state), &tcp6_seq_afinfo))
1996                 return -ENOMEM;
1997         return 0;
1998 }
1999
2000 void tcp6_proc_exit(struct net *net)
2001 {
2002         remove_proc_entry("tcp6", net->proc_net);
2003 }
2004 #endif
2005
2006 struct proto tcpv6_prot = {
2007         .name                   = "TCPv6",
2008         .owner                  = THIS_MODULE,
2009         .close                  = tcp_close,
2010         .pre_connect            = tcp_v6_pre_connect,
2011         .connect                = tcp_v6_connect,
2012         .disconnect             = tcp_disconnect,
2013         .accept                 = inet_csk_accept,
2014         .ioctl                  = tcp_ioctl,
2015         .init                   = tcp_v6_init_sock,
2016         .destroy                = tcp_v6_destroy_sock,
2017         .shutdown               = tcp_shutdown,
2018         .setsockopt             = tcp_setsockopt,
2019         .getsockopt             = tcp_getsockopt,
2020         .keepalive              = tcp_set_keepalive,
2021         .recvmsg                = tcp_recvmsg,
2022         .sendmsg                = tcp_sendmsg,
2023         .sendpage               = tcp_sendpage,
2024         .backlog_rcv            = tcp_v6_do_rcv,
2025         .release_cb             = tcp_release_cb,
2026         .hash                   = inet6_hash,
2027         .unhash                 = inet_unhash,
2028         .get_port               = inet_csk_get_port,
2029         .enter_memory_pressure  = tcp_enter_memory_pressure,
2030         .leave_memory_pressure  = tcp_leave_memory_pressure,
2031         .stream_memory_free     = tcp_stream_memory_free,
2032         .sockets_allocated      = &tcp_sockets_allocated,
2033         .memory_allocated       = &tcp_memory_allocated,
2034         .memory_pressure        = &tcp_memory_pressure,
2035         .orphan_count           = &tcp_orphan_count,
2036         .sysctl_mem             = sysctl_tcp_mem,
2037         .sysctl_wmem_offset     = offsetof(struct net, ipv4.sysctl_tcp_wmem),
2038         .sysctl_rmem_offset     = offsetof(struct net, ipv4.sysctl_tcp_rmem),
2039         .max_header             = MAX_TCP_HEADER,
2040         .obj_size               = sizeof(struct tcp6_sock),
2041         .slab_flags             = SLAB_TYPESAFE_BY_RCU,
2042         .twsk_prot              = &tcp6_timewait_sock_ops,
2043         .rsk_prot               = &tcp6_request_sock_ops,
2044         .h.hashinfo             = &tcp_hashinfo,
2045         .no_autobind            = true,
2046 #ifdef CONFIG_COMPAT
2047         .compat_setsockopt      = compat_tcp_setsockopt,
2048         .compat_getsockopt      = compat_tcp_getsockopt,
2049 #endif
2050         .diag_destroy           = tcp_abort,
2051 };
2052
2053 /* thinking of making this const? Don't.
2054  * early_demux can change based on sysctl.
2055  */
2056 static struct inet6_protocol tcpv6_protocol = {
2057         .early_demux    =       tcp_v6_early_demux,
2058         .early_demux_handler =  tcp_v6_early_demux,
2059         .handler        =       tcp_v6_rcv,
2060         .err_handler    =       tcp_v6_err,
2061         .flags          =       INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
2062 };
2063
2064 static struct inet_protosw tcpv6_protosw = {
2065         .type           =       SOCK_STREAM,
2066         .protocol       =       IPPROTO_TCP,
2067         .prot           =       &tcpv6_prot,
2068         .ops            =       &inet6_stream_ops,
2069         .flags          =       INET_PROTOSW_PERMANENT |
2070                                 INET_PROTOSW_ICSK,
2071 };
2072
2073 static int __net_init tcpv6_net_init(struct net *net)
2074 {
2075         return inet_ctl_sock_create(&net->ipv6.tcp_sk, PF_INET6,
2076                                     SOCK_RAW, IPPROTO_TCP, net);
2077 }
2078
2079 static void __net_exit tcpv6_net_exit(struct net *net)
2080 {
2081         inet_ctl_sock_destroy(net->ipv6.tcp_sk);
2082 }
2083
2084 static void __net_exit tcpv6_net_exit_batch(struct list_head *net_exit_list)
2085 {
2086         inet_twsk_purge(&tcp_hashinfo, AF_INET6);
2087 }
2088
2089 static struct pernet_operations tcpv6_net_ops = {
2090         .init       = tcpv6_net_init,
2091         .exit       = tcpv6_net_exit,
2092         .exit_batch = tcpv6_net_exit_batch,
2093 };
2094
2095 int __init tcpv6_init(void)
2096 {
2097         int ret;
2098
2099         ret = inet6_add_protocol(&tcpv6_protocol, IPPROTO_TCP);
2100         if (ret)
2101                 goto out;
2102
2103         /* register inet6 protocol */
2104         ret = inet6_register_protosw(&tcpv6_protosw);
2105         if (ret)
2106                 goto out_tcpv6_protocol;
2107
2108         ret = register_pernet_subsys(&tcpv6_net_ops);
2109         if (ret)
2110                 goto out_tcpv6_protosw;
2111 out:
2112         return ret;
2113
2114 out_tcpv6_protosw:
2115         inet6_unregister_protosw(&tcpv6_protosw);
2116 out_tcpv6_protocol:
2117         inet6_del_protocol(&tcpv6_protocol, IPPROTO_TCP);
2118         goto out;
2119 }
2120
2121 void tcpv6_exit(void)
2122 {
2123         unregister_pernet_subsys(&tcpv6_net_ops);
2124         inet6_unregister_protosw(&tcpv6_protosw);
2125         inet6_del_protocol(&tcpv6_protocol, IPPROTO_TCP);
2126 }