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
  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/netdma.h>
  63 #include <net/inet_common.h>
  64 #include <net/secure_seq.h>
  65 #include <net/tcp_memcontrol.h>
  66
  67 #include <asm/uaccess.h>
  68
  69 #include <linux/proc_fs.h>
  70 #include <linux/seq_file.h>
  71
  72 #include <linux/crypto.h>
  73 #include <linux/scatterlist.h>
  74
  75 static void     tcp_v6_send_reset(struct sock *sk, struct sk_buff *skb);
  76 static void     tcp_v6_reqsk_send_ack(struct sock *sk, struct sk_buff *skb,
  77                                       struct request_sock *req);
  78
  79 static int      tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb);
  80 static void     __tcp_v6_send_check(struct sk_buff *skb,
  81                                     const struct in6_addr *saddr,
  82                                     const struct in6_addr *daddr);
  83
  84 static const struct inet_connection_sock_af_ops ipv6_mapped;
  85 static const struct inet_connection_sock_af_ops ipv6_specific;
  86 #ifdef CONFIG_TCP_MD5SIG
  87 static const struct tcp_sock_af_ops tcp_sock_ipv6_specific;
  88 static const struct tcp_sock_af_ops tcp_sock_ipv6_mapped_specific;
  89 #else
  90 static struct tcp_md5sig_key *tcp_v6_md5_do_lookup(struct sock *sk,
  91                                                    const struct in6_addr *addr)
  92 {
  93         return NULL;
  94 }
  95 #endif
  96
  97 static void tcp_v6_hash(struct sock *sk)
  98 {
  99         if (sk->sk_state != TCP_CLOSE) {
 100                 if (inet_csk(sk)->icsk_af_ops == &ipv6_mapped) {
 101                         tcp_prot.hash(sk);
 102                         return;
 103                 }
 104                 local_bh_disable();
 105                 __inet6_hash(sk, NULL);
 106                 local_bh_enable();
 107         }
 108 }
 109
 110 static __inline__ __sum16 tcp_v6_check(int len,
 111                                    const struct in6_addr *saddr,
 112                                    const struct in6_addr *daddr,
 113                                    __wsum base)
 114 {
 115         return csum_ipv6_magic(saddr, daddr, len, IPPROTO_TCP, base);
 116 }
 117
 118 static __u32 tcp_v6_init_sequence(const struct sk_buff *skb)
 119 {
 120         return secure_tcpv6_sequence_number(ipv6_hdr(skb)->daddr.s6_addr32,
 121                                             ipv6_hdr(skb)->saddr.s6_addr32,
 122                                             tcp_hdr(skb)->dest,
 123                                             tcp_hdr(skb)->source);
 124 }
 125
 126 static int tcp_v6_connect(struct sock *sk, struct sockaddr *uaddr,
 127                           int addr_len)
 128 {
 129         struct sockaddr_in6 *usin = (struct sockaddr_in6 *) uaddr;
 130         struct inet_sock *inet = inet_sk(sk);
 131         struct inet_connection_sock *icsk = inet_csk(sk);
 132         struct ipv6_pinfo *np = inet6_sk(sk);
 133         struct tcp_sock *tp = tcp_sk(sk);
 134         struct in6_addr *saddr = NULL, *final_p, final;
 135         struct rt6_info *rt;
 136         struct flowi6 fl6;
 137         struct dst_entry *dst;
 138         int addr_type;
 139         int err;
 140
 141         if (addr_len < SIN6_LEN_RFC2133)
 142                 return -EINVAL;
 143
 144         if (usin->sin6_family != AF_INET6)
 145                 return -EAFNOSUPPORT;
 146
 147         memset(&fl6, 0, sizeof(fl6));
 148
 149         if (np->sndflow) {
 150                 fl6.flowlabel = usin->sin6_flowinfo&IPV6_FLOWINFO_MASK;
 151                 IP6_ECN_flow_init(fl6.flowlabel);
 152                 if (fl6.flowlabel&IPV6_FLOWLABEL_MASK) {
 153                         struct ip6_flowlabel *flowlabel;
 154                         flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
 155                         if (flowlabel == NULL)
 156                                 return -EINVAL;
 157                         usin->sin6_addr = flowlabel->dst;
 158                         fl6_sock_release(flowlabel);
 159                 }
 160         }
 161
 162         /*
 163          *      connect() to INADDR_ANY means loopback (BSD'ism).
 164          */
 165
 166         if(ipv6_addr_any(&usin->sin6_addr))
 167                 usin->sin6_addr.s6_addr[15] = 0x1;
 168
 169         addr_type = ipv6_addr_type(&usin->sin6_addr);
 170
 171         if(addr_type & IPV6_ADDR_MULTICAST)
 172                 return -ENETUNREACH;
 173
 174         if (addr_type&IPV6_ADDR_LINKLOCAL) {
 175                 if (addr_len >= sizeof(struct sockaddr_in6) &&
 176                     usin->sin6_scope_id) {
 177                         /* If interface is set while binding, indices
 178                          * must coincide.
 179                          */
 180                         if (sk->sk_bound_dev_if &&
 181                             sk->sk_bound_dev_if != usin->sin6_scope_id)
 182                                 return -EINVAL;
 183
 184                         sk->sk_bound_dev_if = usin->sin6_scope_id;
 185                 }
 186
 187                 /* Connect to link-local address requires an interface */
 188                 if (!sk->sk_bound_dev_if)
 189                         return -EINVAL;
 190         }
 191
 192         if (tp->rx_opt.ts_recent_stamp &&
 193             !ipv6_addr_equal(&np->daddr, &usin->sin6_addr)) {
 194                 tp->rx_opt.ts_recent = 0;
 195                 tp->rx_opt.ts_recent_stamp = 0;
 196                 tp->write_seq = 0;
 197         }
 198
 199         np->daddr = usin->sin6_addr;
 200         np->flow_label = fl6.flowlabel;
 201
 202         /*
 203          *      TCP over IPv4
 204          */
 205
 206         if (addr_type == IPV6_ADDR_MAPPED) {
 207                 u32 exthdrlen = icsk->icsk_ext_hdr_len;
 208                 struct sockaddr_in sin;
 209
 210                 SOCK_DEBUG(sk, "connect: ipv4 mapped\n");
 211
 212                 if (__ipv6_only_sock(sk))
 213                         return -ENETUNREACH;
 214
 215                 sin.sin_family = AF_INET;
 216                 sin.sin_port = usin->sin6_port;
 217                 sin.sin_addr.s_addr = usin->sin6_addr.s6_addr32[3];
 218
 219                 icsk->icsk_af_ops = &ipv6_mapped;
 220                 sk->sk_backlog_rcv = tcp_v4_do_rcv;
 221 #ifdef CONFIG_TCP_MD5SIG
 222                 tp->af_specific = &tcp_sock_ipv6_mapped_specific;
 223 #endif
 224
 225                 err = tcp_v4_connect(sk, (struct sockaddr *)&sin, sizeof(sin));
 226
 227                 if (err) {
 228                         icsk->icsk_ext_hdr_len = exthdrlen;
 229                         icsk->icsk_af_ops = &ipv6_specific;
 230                         sk->sk_backlog_rcv = tcp_v6_do_rcv;
 231 #ifdef CONFIG_TCP_MD5SIG
 232                         tp->af_specific = &tcp_sock_ipv6_specific;
 233 #endif
 234                         goto failure;
 235                 } else {
 236                         ipv6_addr_set_v4mapped(inet->inet_saddr, &np->saddr);
 237                         ipv6_addr_set_v4mapped(inet->inet_rcv_saddr,
 238                                                &np->rcv_saddr);
 239                 }
 240
 241                 return err;
 242         }
 243
 244         if (!ipv6_addr_any(&np->rcv_saddr))
 245                 saddr = &np->rcv_saddr;
 246
 247         fl6.flowi6_proto = IPPROTO_TCP;
 248         fl6.daddr = np->daddr;
 249         fl6.saddr = saddr ? *saddr : np->saddr;
 250         fl6.flowi6_oif = sk->sk_bound_dev_if;
 251         fl6.flowi6_mark = sk->sk_mark;
 252         fl6.fl6_dport = usin->sin6_port;
 253         fl6.fl6_sport = inet->inet_sport;
 254
 255         final_p = fl6_update_dst(&fl6, np->opt, &final);
 256
 257         security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));
 258
 259         dst = ip6_dst_lookup_flow(sk, &fl6, final_p, true);
 260         if (IS_ERR(dst)) {
 261                 err = PTR_ERR(dst);
 262                 goto failure;
 263         }
 264
 265         if (saddr == NULL) {
 266                 saddr = &fl6.saddr;
 267                 np->rcv_saddr = *saddr;
 268         }
 269
 270         /* set the source address */
 271         np->saddr = *saddr;
 272         inet->inet_rcv_saddr = LOOPBACK4_IPV6;
 273
 274         sk->sk_gso_type = SKB_GSO_TCPV6;
 275         __ip6_dst_store(sk, dst, NULL, NULL);
 276
 277         rt = (struct rt6_info *) dst;
 278         if (tcp_death_row.sysctl_tw_recycle &&
 279             !tp->rx_opt.ts_recent_stamp &&
 280             ipv6_addr_equal(&rt->rt6i_dst.addr, &np->daddr)) {
 281                 struct inet_peer *peer = rt6_get_peer(rt);
 282                 /*
 283                  * VJ's idea. We save last timestamp seen from
 284                  * the destination in peer table, when entering state
 285                  * TIME-WAIT * and initialize rx_opt.ts_recent from it,
 286                  * when trying new connection.
 287                  */
 288                 if (peer) {
 289                         inet_peer_refcheck(peer);
 290                         if ((u32)get_seconds() - peer->tcp_ts_stamp <= TCP_PAWS_MSL) {
 291                                 tp->rx_opt.ts_recent_stamp = peer->tcp_ts_stamp;
 292                                 tp->rx_opt.ts_recent = peer->tcp_ts;
 293                         }
 294                 }
 295         }
 296
 297         icsk->icsk_ext_hdr_len = 0;
 298         if (np->opt)
 299                 icsk->icsk_ext_hdr_len = (np->opt->opt_flen +
 300                                           np->opt->opt_nflen);
 301
 302         tp->rx_opt.mss_clamp = IPV6_MIN_MTU - sizeof(struct tcphdr) - sizeof(struct ipv6hdr);
 303
 304         inet->inet_dport = usin->sin6_port;
 305
 306         tcp_set_state(sk, TCP_SYN_SENT);
 307         err = inet6_hash_connect(&tcp_death_row, sk);
 308         if (err)
 309                 goto late_failure;
 310
 311         if (!tp->write_seq)
 312                 tp->write_seq = secure_tcpv6_sequence_number(np->saddr.s6_addr32,
 313                                                              np->daddr.s6_addr32,
 314                                                              inet->inet_sport,
 315                                                              inet->inet_dport);
 316
 317         err = tcp_connect(sk);
 318         if (err)
 319                 goto late_failure;
 320
 321         return 0;
 322
 323 late_failure:
 324         tcp_set_state(sk, TCP_CLOSE);
 325         __sk_dst_reset(sk);
 326 failure:
 327         inet->inet_dport = 0;
 328         sk->sk_route_caps = 0;
 329         return err;
 330 }
 331
 332 static void tcp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 333                 u8 type, u8 code, int offset, __be32 info)
 334 {
 335         const struct ipv6hdr *hdr = (const struct ipv6hdr*)skb->data;
 336         const struct tcphdr *th = (struct tcphdr *)(skb->data+offset);
 337         struct ipv6_pinfo *np;
 338         struct sock *sk;
 339         int err;
 340         struct tcp_sock *tp;
 341         __u32 seq;
 342         struct net *net = dev_net(skb->dev);
 343
 344         sk = inet6_lookup(net, &tcp_hashinfo, &hdr->daddr,
 345                         th->dest, &hdr->saddr, th->source, skb->dev->ifindex);
 346
 347         if (sk == NULL) {
 348                 ICMP6_INC_STATS_BH(net, __in6_dev_get(skb->dev),
 349                                    ICMP6_MIB_INERRORS);
 350                 return;
 351         }
 352
 353         if (sk->sk_state == TCP_TIME_WAIT) {
 354                 inet_twsk_put(inet_twsk(sk));
 355                 return;
 356         }
 357
 358         bh_lock_sock(sk);
 359         if (sock_owned_by_user(sk))
 360                 NET_INC_STATS_BH(net, LINUX_MIB_LOCKDROPPEDICMPS);
 361
 362         if (sk->sk_state == TCP_CLOSE)
 363                 goto out;
 364
 365         if (ipv6_hdr(skb)->hop_limit < inet6_sk(sk)->min_hopcount) {
 366                 NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP);
 367                 goto out;
 368         }
 369
 370         tp = tcp_sk(sk);
 371         seq = ntohl(th->seq);
 372         if (sk->sk_state != TCP_LISTEN &&
 373             !between(seq, tp->snd_una, tp->snd_nxt)) {
 374                 NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
 375                 goto out;
 376         }
 377
 378         np = inet6_sk(sk);
 379
 380         if (type == ICMPV6_PKT_TOOBIG) {
 381                 struct dst_entry *dst;
 382
 383                 if (sock_owned_by_user(sk))
 384                         goto out;
 385                 if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE))
 386                         goto out;
 387
 388                 /* icmp should have updated the destination cache entry */
 389                 dst = __sk_dst_check(sk, np->dst_cookie);
 390
 391                 if (dst == NULL) {
 392                         struct inet_sock *inet = inet_sk(sk);
 393                         struct flowi6 fl6;
 394
 395                         /* BUGGG_FUTURE: Again, it is not clear how
 396                            to handle rthdr case. Ignore this complexity
 397                            for now.
 398                          */
 399                         memset(&fl6, 0, sizeof(fl6));
 400                         fl6.flowi6_proto = IPPROTO_TCP;
 401                         fl6.daddr = np->daddr;
 402                         fl6.saddr = np->saddr;
 403                         fl6.flowi6_oif = sk->sk_bound_dev_if;
 404                         fl6.flowi6_mark = sk->sk_mark;
 405                         fl6.fl6_dport = inet->inet_dport;
 406                         fl6.fl6_sport = inet->inet_sport;
 407                         security_skb_classify_flow(skb, flowi6_to_flowi(&fl6));
 408
 409                         dst = ip6_dst_lookup_flow(sk, &fl6, NULL, false);
 410                         if (IS_ERR(dst)) {
 411                                 sk->sk_err_soft = -PTR_ERR(dst);
 412                                 goto out;
 413                         }
 414
 415                 } else
 416                         dst_hold(dst);
 417
 418                 if (inet_csk(sk)->icsk_pmtu_cookie > dst_mtu(dst)) {
 419                         tcp_sync_mss(sk, dst_mtu(dst));
 420                         tcp_simple_retransmit(sk);
 421                 } /* else let the usual retransmit timer handle it */
 422                 dst_release(dst);
 423                 goto out;
 424         }
 425
 426         icmpv6_err_convert(type, code, &err);
 427
 428         /* Might be for an request_sock */
 429         switch (sk->sk_state) {
 430                 struct request_sock *req, **prev;
 431         case TCP_LISTEN:
 432                 if (sock_owned_by_user(sk))
 433                         goto out;
 434
 435                 req = inet6_csk_search_req(sk, &prev, th->dest, &hdr->daddr,
 436                                            &hdr->saddr, inet6_iif(skb));
 437                 if (!req)
 438                         goto out;
 439
 440                 /* ICMPs are not backlogged, hence we cannot get
 441                  * an established socket here.
 442                  */
 443                 WARN_ON(req->sk != NULL);
 444
 445                 if (seq != tcp_rsk(req)->snt_isn) {
 446                         NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
 447                         goto out;
 448                 }
 449
 450                 inet_csk_reqsk_queue_drop(sk, req, prev);
 451                 goto out;
 452
 453         case TCP_SYN_SENT:
 454         case TCP_SYN_RECV:  /* Cannot happen.
 455                                It can, it SYNs are crossed. --ANK */
 456                 if (!sock_owned_by_user(sk)) {
 457                         sk->sk_err = err;
 458                         sk->sk_error_report(sk);                /* Wake people up to see the error (see connect in sock.c) */
 459
 460                         tcp_done(sk);
 461                 } else
 462                         sk->sk_err_soft = err;
 463                 goto out;
 464         }
 465
 466         if (!sock_owned_by_user(sk) && np->recverr) {
 467                 sk->sk_err = err;
 468                 sk->sk_error_report(sk);
 469         } else
 470                 sk->sk_err_soft = err;
 471
 472 out:
 473         bh_unlock_sock(sk);
 474         sock_put(sk);
 475 }
 476
 477
 478 static int tcp_v6_send_synack(struct sock *sk, struct request_sock *req,
 479                               struct request_values *rvp,
 480                               u16 queue_mapping)
 481 {
 482         struct inet6_request_sock *treq = inet6_rsk(req);
 483         struct ipv6_pinfo *np = inet6_sk(sk);
 484         struct sk_buff * skb;
 485         struct ipv6_txoptions *opt = NULL;
 486         struct in6_addr * final_p, final;
 487         struct flowi6 fl6;
 488         struct dst_entry *dst;
 489         int err;
 490
 491         memset(&fl6, 0, sizeof(fl6));
 492         fl6.flowi6_proto = IPPROTO_TCP;
 493         fl6.daddr = treq->rmt_addr;
 494         fl6.saddr = treq->loc_addr;
 495         fl6.flowlabel = 0;
 496         fl6.flowi6_oif = treq->iif;
 497         fl6.flowi6_mark = sk->sk_mark;
 498         fl6.fl6_dport = inet_rsk(req)->rmt_port;
 499         fl6.fl6_sport = inet_rsk(req)->loc_port;
 500         security_req_classify_flow(req, flowi6_to_flowi(&fl6));
 501
 502         opt = np->opt;
 503         final_p = fl6_update_dst(&fl6, opt, &final);
 504
 505         dst = ip6_dst_lookup_flow(sk, &fl6, final_p, false);
 506         if (IS_ERR(dst)) {
 507                 err = PTR_ERR(dst);
 508                 dst = NULL;
 509                 goto done;
 510         }
 511         skb = tcp_make_synack(sk, dst, req, rvp);
 512         err = -ENOMEM;
 513         if (skb) {
 514                 __tcp_v6_send_check(skb, &treq->loc_addr, &treq->rmt_addr);
 515
 516                 fl6.daddr = treq->rmt_addr;
 517                 skb_set_queue_mapping(skb, queue_mapping);
 518                 err = ip6_xmit(sk, skb, &fl6, opt, np->tclass);
 519                 err = net_xmit_eval(err);
 520         }
 521
 522 done:
 523         if (opt && opt != np->opt)
 524                 sock_kfree_s(sk, opt, opt->tot_len);
 525         dst_release(dst);
 526         return err;
 527 }
 528
 529 static int tcp_v6_rtx_synack(struct sock *sk, struct request_sock *req,
 530                              struct request_values *rvp)
 531 {
 532         TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_RETRANSSEGS);
 533         return tcp_v6_send_synack(sk, req, rvp, 0);
 534 }
 535
 536 static void tcp_v6_reqsk_destructor(struct request_sock *req)
 537 {
 538         kfree_skb(inet6_rsk(req)->pktopts);
 539 }
 540
 541 #ifdef CONFIG_TCP_MD5SIG
 542 static struct tcp_md5sig_key *tcp_v6_md5_do_lookup(struct sock *sk,
 543                                                    const struct in6_addr *addr)
 544 {
 545         return tcp_md5_do_lookup(sk, (union tcp_md5_addr *)addr, AF_INET6);
 546 }
 547
 548 static struct tcp_md5sig_key *tcp_v6_md5_lookup(struct sock *sk,
 549                                                 struct sock *addr_sk)
 550 {
 551         return tcp_v6_md5_do_lookup(sk, &inet6_sk(addr_sk)->daddr);
 552 }
 553
 554 static struct tcp_md5sig_key *tcp_v6_reqsk_md5_lookup(struct sock *sk,
 555                                                       struct request_sock *req)
 556 {
 557         return tcp_v6_md5_do_lookup(sk, &inet6_rsk(req)->rmt_addr);
 558 }
 559
 560 static int tcp_v6_parse_md5_keys (struct sock *sk, char __user *optval,
 561                                   int optlen)
 562 {
 563         struct tcp_md5sig cmd;
 564         struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)&cmd.tcpm_addr;
 565
 566         if (optlen < sizeof(cmd))
 567                 return -EINVAL;
 568
 569         if (copy_from_user(&cmd, optval, sizeof(cmd)))
 570                 return -EFAULT;
 571
 572         if (sin6->sin6_family != AF_INET6)
 573                 return -EINVAL;
 574
 575         if (!cmd.tcpm_keylen) {
 576                 if (ipv6_addr_v4mapped(&sin6->sin6_addr))
 577                         return tcp_md5_do_del(sk, (union tcp_md5_addr *)&sin6->sin6_addr.s6_addr32[3],
 578                                               AF_INET);
 579                 return tcp_md5_do_del(sk, (union tcp_md5_addr *)&sin6->sin6_addr,
 580                                       AF_INET6);
 581         }
 582
 583         if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN)
 584                 return -EINVAL;
 585
 586         if (ipv6_addr_v4mapped(&sin6->sin6_addr))
 587                 return tcp_md5_do_add(sk, (union tcp_md5_addr *)&sin6->sin6_addr.s6_addr32[3],
 588                                       AF_INET, cmd.tcpm_key, cmd.tcpm_keylen, GFP_KERNEL);
 589
 590         return tcp_md5_do_add(sk, (union tcp_md5_addr *)&sin6->sin6_addr,
 591                               AF_INET6, cmd.tcpm_key, cmd.tcpm_keylen, GFP_KERNEL);
 592 }
 593
 594 static int tcp_v6_md5_hash_pseudoheader(struct tcp_md5sig_pool *hp,
 595                                         const struct in6_addr *daddr,
 596                                         const struct in6_addr *saddr, int nbytes)
 597 {
 598         struct tcp6_pseudohdr *bp;
 599         struct scatterlist sg;
 600
 601         bp = &hp->md5_blk.ip6;
 602         /* 1. TCP pseudo-header (RFC2460) */
 603         bp->saddr = *saddr;
 604         bp->daddr = *daddr;
 605         bp->protocol = cpu_to_be32(IPPROTO_TCP);
 606         bp->len = cpu_to_be32(nbytes);
 607
 608         sg_init_one(&sg, bp, sizeof(*bp));
 609         return crypto_hash_update(&hp->md5_desc, &sg, sizeof(*bp));
 610 }
 611
 612 static int tcp_v6_md5_hash_hdr(char *md5_hash, struct tcp_md5sig_key *key,
 613                                const struct in6_addr *daddr, struct in6_addr *saddr,
 614                                const struct tcphdr *th)
 615 {
 616         struct tcp_md5sig_pool *hp;
 617         struct hash_desc *desc;
 618
 619         hp = tcp_get_md5sig_pool();
 620         if (!hp)
 621                 goto clear_hash_noput;
 622         desc = &hp->md5_desc;
 623
 624         if (crypto_hash_init(desc))
 625                 goto clear_hash;
 626         if (tcp_v6_md5_hash_pseudoheader(hp, daddr, saddr, th->doff << 2))
 627                 goto clear_hash;
 628         if (tcp_md5_hash_header(hp, th))
 629                 goto clear_hash;
 630         if (tcp_md5_hash_key(hp, key))
 631                 goto clear_hash;
 632         if (crypto_hash_final(desc, md5_hash))
 633                 goto clear_hash;
 634
 635         tcp_put_md5sig_pool();
 636         return 0;
 637
 638 clear_hash:
 639         tcp_put_md5sig_pool();
 640 clear_hash_noput:
 641         memset(md5_hash, 0, 16);
 642         return 1;
 643 }
 644
 645 static int tcp_v6_md5_hash_skb(char *md5_hash, struct tcp_md5sig_key *key,
 646                                const struct sock *sk,
 647                                const struct request_sock *req,
 648                                const struct sk_buff *skb)
 649 {
 650         const struct in6_addr *saddr, *daddr;
 651         struct tcp_md5sig_pool *hp;
 652         struct hash_desc *desc;
 653         const struct tcphdr *th = tcp_hdr(skb);
 654
 655         if (sk) {
 656                 saddr = &inet6_sk(sk)->saddr;
 657                 daddr = &inet6_sk(sk)->daddr;
 658         } else if (req) {
 659                 saddr = &inet6_rsk(req)->loc_addr;
 660                 daddr = &inet6_rsk(req)->rmt_addr;
 661         } else {
 662                 const struct ipv6hdr *ip6h = ipv6_hdr(skb);
 663                 saddr = &ip6h->saddr;
 664                 daddr = &ip6h->daddr;
 665         }
 666
 667         hp = tcp_get_md5sig_pool();
 668         if (!hp)
 669                 goto clear_hash_noput;
 670         desc = &hp->md5_desc;
 671
 672         if (crypto_hash_init(desc))
 673                 goto clear_hash;
 674
 675         if (tcp_v6_md5_hash_pseudoheader(hp, daddr, saddr, skb->len))
 676                 goto clear_hash;
 677         if (tcp_md5_hash_header(hp, th))
 678                 goto clear_hash;
 679         if (tcp_md5_hash_skb_data(hp, skb, th->doff << 2))
 680                 goto clear_hash;
 681         if (tcp_md5_hash_key(hp, key))
 682                 goto clear_hash;
 683         if (crypto_hash_final(desc, md5_hash))
 684                 goto clear_hash;
 685
 686         tcp_put_md5sig_pool();
 687         return 0;
 688
 689 clear_hash:
 690         tcp_put_md5sig_pool();
 691 clear_hash_noput:
 692         memset(md5_hash, 0, 16);
 693         return 1;
 694 }
 695
 696 static int tcp_v6_inbound_md5_hash(struct sock *sk, const struct sk_buff *skb)
 697 {
 698         const __u8 *hash_location = NULL;
 699         struct tcp_md5sig_key *hash_expected;
 700         const struct ipv6hdr *ip6h = ipv6_hdr(skb);
 701         const struct tcphdr *th = tcp_hdr(skb);
 702         int genhash;
 703         u8 newhash[16];
 704
 705         hash_expected = tcp_v6_md5_do_lookup(sk, &ip6h->saddr);
 706         hash_location = tcp_parse_md5sig_option(th);
 707
 708         /* We've parsed the options - do we have a hash? */
 709         if (!hash_expected && !hash_location)
 710                 return 0;
 711
 712         if (hash_expected && !hash_location) {
 713                 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5NOTFOUND);
 714                 return 1;
 715         }
 716
 717         if (!hash_expected && hash_location) {
 718                 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5UNEXPECTED);
 719                 return 1;
 720         }
 721
 722         /* check the signature */
 723         genhash = tcp_v6_md5_hash_skb(newhash,
 724                                       hash_expected,
 725                                       NULL, NULL, skb);
 726
 727         if (genhash || memcmp(hash_location, newhash, 16) != 0) {
 728                 net_info_ratelimited("MD5 Hash %s for [%pI6c]:%u->[%pI6c]:%u\n",
 729                                      genhash ? "failed" : "mismatch",
 730                                      &ip6h->saddr, ntohs(th->source),
 731                                      &ip6h->daddr, ntohs(th->dest));
 732                 return 1;
 733         }
 734         return 0;
 735 }
 736 #endif
 737
 738 struct request_sock_ops tcp6_request_sock_ops __read_mostly = {
 739         .family         =       AF_INET6,
 740         .obj_size       =       sizeof(struct tcp6_request_sock),
 741         .rtx_syn_ack    =       tcp_v6_rtx_synack,
 742         .send_ack       =       tcp_v6_reqsk_send_ack,
 743         .destructor     =       tcp_v6_reqsk_destructor,
 744         .send_reset     =       tcp_v6_send_reset,
 745         .syn_ack_timeout =      tcp_syn_ack_timeout,
 746 };
 747
 748 #ifdef CONFIG_TCP_MD5SIG
 749 static const struct tcp_request_sock_ops tcp_request_sock_ipv6_ops = {
 750         .md5_lookup     =       tcp_v6_reqsk_md5_lookup,
 751         .calc_md5_hash  =       tcp_v6_md5_hash_skb,
 752 };
 753 #endif
 754
 755 static void __tcp_v6_send_check(struct sk_buff *skb,
 756                                 const struct in6_addr *saddr, const struct in6_addr *daddr)
 757 {
 758         struct tcphdr *th = tcp_hdr(skb);
 759
 760         if (skb->ip_summed == CHECKSUM_PARTIAL) {
 761                 th->check = ~tcp_v6_check(skb->len, saddr, daddr, 0);
 762                 skb->csum_start = skb_transport_header(skb) - skb->head;
 763                 skb->csum_offset = offsetof(struct tcphdr, check);
 764         } else {
 765                 th->check = tcp_v6_check(skb->len, saddr, daddr,
 766                                          csum_partial(th, th->doff << 2,
 767                                                       skb->csum));
 768         }
 769 }
 770
 771 static void tcp_v6_send_check(struct sock *sk, struct sk_buff *skb)
 772 {
 773         struct ipv6_pinfo *np = inet6_sk(sk);
 774
 775         __tcp_v6_send_check(skb, &np->saddr, &np->daddr);
 776 }
 777
 778 static int tcp_v6_gso_send_check(struct sk_buff *skb)
 779 {
 780         const struct ipv6hdr *ipv6h;
 781         struct tcphdr *th;
 782
 783         if (!pskb_may_pull(skb, sizeof(*th)))
 784                 return -EINVAL;
 785
 786         ipv6h = ipv6_hdr(skb);
 787         th = tcp_hdr(skb);
 788
 789         th->check = 0;
 790         skb->ip_summed = CHECKSUM_PARTIAL;
 791         __tcp_v6_send_check(skb, &ipv6h->saddr, &ipv6h->daddr);
 792         return 0;
 793 }
 794
 795 static struct sk_buff **tcp6_gro_receive(struct sk_buff **head,
 796                                          struct sk_buff *skb)
 797 {
 798         const struct ipv6hdr *iph = skb_gro_network_header(skb);
 799
 800         switch (skb->ip_summed) {
 801         case CHECKSUM_COMPLETE:
 802                 if (!tcp_v6_check(skb_gro_len(skb), &iph->saddr, &iph->daddr,
 803                                   skb->csum)) {
 804                         skb->ip_summed = CHECKSUM_UNNECESSARY;
 805                         break;
 806                 }
 807
 808                 /* fall through */
 809         case CHECKSUM_NONE:
 810                 NAPI_GRO_CB(skb)->flush = 1;
 811                 return NULL;
 812         }
 813
 814         return tcp_gro_receive(head, skb);
 815 }
 816
 817 static int tcp6_gro_complete(struct sk_buff *skb)
 818 {
 819         const struct ipv6hdr *iph = ipv6_hdr(skb);
 820         struct tcphdr *th = tcp_hdr(skb);
 821
 822         th->check = ~tcp_v6_check(skb->len - skb_transport_offset(skb),
 823                                   &iph->saddr, &iph->daddr, 0);
 824         skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
 825
 826         return tcp_gro_complete(skb);
 827 }
 828
 829 static void tcp_v6_send_response(struct sk_buff *skb, u32 seq, u32 ack, u32 win,
 830                                  u32 ts, struct tcp_md5sig_key *key, int rst, u8 tclass)
 831 {
 832         const struct tcphdr *th = tcp_hdr(skb);
 833         struct tcphdr *t1;
 834         struct sk_buff *buff;
 835         struct flowi6 fl6;
 836         struct net *net = dev_net(skb_dst(skb)->dev);
 837         struct sock *ctl_sk = net->ipv6.tcp_sk;
 838         unsigned int tot_len = sizeof(struct tcphdr);
 839         struct dst_entry *dst;
 840         __be32 *topt;
 841
 842         if (ts)
 843                 tot_len += TCPOLEN_TSTAMP_ALIGNED;
 844 #ifdef CONFIG_TCP_MD5SIG
 845         if (key)
 846                 tot_len += TCPOLEN_MD5SIG_ALIGNED;
 847 #endif
 848
 849         buff = alloc_skb(MAX_HEADER + sizeof(struct ipv6hdr) + tot_len,
 850                          GFP_ATOMIC);
 851         if (buff == NULL)
 852                 return;
 853
 854         skb_reserve(buff, MAX_HEADER + sizeof(struct ipv6hdr) + tot_len);
 855
 856         t1 = (struct tcphdr *) skb_push(buff, tot_len);
 857         skb_reset_transport_header(buff);
 858
 859         /* Swap the send and the receive. */
 860         memset(t1, 0, sizeof(*t1));
 861         t1->dest = th->source;
 862         t1->source = th->dest;
 863         t1->doff = tot_len / 4;
 864         t1->seq = htonl(seq);
 865         t1->ack_seq = htonl(ack);
 866         t1->ack = !rst || !th->ack;
 867         t1->rst = rst;
 868         t1->window = htons(win);
 869
 870         topt = (__be32 *)(t1 + 1);
 871
 872         if (ts) {
 873                 *topt++ = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
 874                                 (TCPOPT_TIMESTAMP << 8) | TCPOLEN_TIMESTAMP);
 875                 *topt++ = htonl(tcp_time_stamp);
 876                 *topt++ = htonl(ts);
 877         }
 878
 879 #ifdef CONFIG_TCP_MD5SIG
 880         if (key) {
 881                 *topt++ = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
 882                                 (TCPOPT_MD5SIG << 8) | TCPOLEN_MD5SIG);
 883                 tcp_v6_md5_hash_hdr((__u8 *)topt, key,
 884                                     &ipv6_hdr(skb)->saddr,
 885                                     &ipv6_hdr(skb)->daddr, t1);
 886         }
 887 #endif
 888
 889         memset(&fl6, 0, sizeof(fl6));
 890         fl6.daddr = ipv6_hdr(skb)->saddr;
 891         fl6.saddr = ipv6_hdr(skb)->daddr;
 892
 893         buff->ip_summed = CHECKSUM_PARTIAL;
 894         buff->csum = 0;
 895
 896         __tcp_v6_send_check(buff, &fl6.saddr, &fl6.daddr);
 897
 898         fl6.flowi6_proto = IPPROTO_TCP;
 899         fl6.flowi6_oif = inet6_iif(skb);
 900         fl6.fl6_dport = t1->dest;
 901         fl6.fl6_sport = t1->source;
 902         security_skb_classify_flow(skb, flowi6_to_flowi(&fl6));
 903
 904         /* Pass a socket to ip6_dst_lookup either it is for RST
 905          * Underlying function will use this to retrieve the network
 906          * namespace
 907          */
 908         dst = ip6_dst_lookup_flow(ctl_sk, &fl6, NULL, false);
 909         if (!IS_ERR(dst)) {
 910                 skb_dst_set(buff, dst);
 911                 ip6_xmit(ctl_sk, buff, &fl6, NULL, tclass);
 912                 TCP_INC_STATS_BH(net, TCP_MIB_OUTSEGS);
 913                 if (rst)
 914                         TCP_INC_STATS_BH(net, TCP_MIB_OUTRSTS);
 915                 return;
 916         }
 917
 918         kfree_skb(buff);
 919 }
 920
 921 static void tcp_v6_send_reset(struct sock *sk, struct sk_buff *skb)
 922 {
 923         const struct tcphdr *th = tcp_hdr(skb);
 924         u32 seq = 0, ack_seq = 0;
 925         struct tcp_md5sig_key *key = NULL;
 926 #ifdef CONFIG_TCP_MD5SIG
 927         const __u8 *hash_location = NULL;
 928         struct ipv6hdr *ipv6h = ipv6_hdr(skb);
 929         unsigned char newhash[16];
 930         int genhash;
 931         struct sock *sk1 = NULL;
 932 #endif
 933
 934         if (th->rst)
 935                 return;
 936
 937         if (!ipv6_unicast_destination(skb))
 938                 return;
 939
 940 #ifdef CONFIG_TCP_MD5SIG
 941         hash_location = tcp_parse_md5sig_option(th);
 942         if (!sk && hash_location) {
 943                 /*
 944                  * active side is lost. Try to find listening socket through
 945                  * source port, and then find md5 key through listening socket.
 946                  * we are not loose security here:
 947                  * Incoming packet is checked with md5 hash with finding key,
 948                  * no RST generated if md5 hash doesn't match.
 949                  */
 950                 sk1 = inet6_lookup_listener(dev_net(skb_dst(skb)->dev),
 951                                            &tcp_hashinfo, &ipv6h->daddr,
 952                                            ntohs(th->source), inet6_iif(skb));
 953                 if (!sk1)
 954                         return;
 955
 956                 rcu_read_lock();
 957                 key = tcp_v6_md5_do_lookup(sk1, &ipv6h->saddr);
 958                 if (!key)
 959                         goto release_sk1;
 960
 961                 genhash = tcp_v6_md5_hash_skb(newhash, key, NULL, NULL, skb);
 962                 if (genhash || memcmp(hash_location, newhash, 16) != 0)
 963                         goto release_sk1;
 964         } else {
 965                 key = sk ? tcp_v6_md5_do_lookup(sk, &ipv6h->saddr) : NULL;
 966         }
 967 #endif
 968
 969         if (th->ack)
 970                 seq = ntohl(th->ack_seq);
 971         else
 972                 ack_seq = ntohl(th->seq) + th->syn + th->fin + skb->len -
 973                           (th->doff << 2);
 974
 975         tcp_v6_send_response(skb, seq, ack_seq, 0, 0, key, 1, 0);
 976
 977 #ifdef CONFIG_TCP_MD5SIG
 978 release_sk1:
 979         if (sk1) {
 980                 rcu_read_unlock();
 981                 sock_put(sk1);
 982         }
 983 #endif
 984 }
 985
 986 static void tcp_v6_send_ack(struct sk_buff *skb, u32 seq, u32 ack, u32 win, u32 ts,
 987                             struct tcp_md5sig_key *key, u8 tclass)
 988 {
 989         tcp_v6_send_response(skb, seq, ack, win, ts, key, 0, tclass);
 990 }
 991
 992 static void tcp_v6_timewait_ack(struct sock *sk, struct sk_buff *skb)
 993 {
 994         struct inet_timewait_sock *tw = inet_twsk(sk);
 995         struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
 996
 997         tcp_v6_send_ack(skb, tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
 998                         tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
 999                         tcptw->tw_ts_recent, tcp_twsk_md5_key(tcptw),
1000                         tw->tw_tclass);
1001
1002         inet_twsk_put(tw);
1003 }
1004
1005 static void tcp_v6_reqsk_send_ack(struct sock *sk, struct sk_buff *skb,
1006                                   struct request_sock *req)
1007 {
1008         tcp_v6_send_ack(skb, tcp_rsk(req)->snt_isn + 1, tcp_rsk(req)->rcv_isn + 1, req->rcv_wnd, req->ts_recent,
1009                         tcp_v6_md5_do_lookup(sk, &ipv6_hdr(skb)->daddr), 0);
1010 }
1011
1012
1013 static struct sock *tcp_v6_hnd_req(struct sock *sk,struct sk_buff *skb)
1014 {
1015         struct request_sock *req, **prev;
1016         const struct tcphdr *th = tcp_hdr(skb);
1017         struct sock *nsk;
1018
1019         /* Find possible connection requests. */
1020         req = inet6_csk_search_req(sk, &prev, th->source,
1021                                    &ipv6_hdr(skb)->saddr,
1022                                    &ipv6_hdr(skb)->daddr, inet6_iif(skb));
1023         if (req)
1024                 return tcp_check_req(sk, skb, req, prev);
1025
1026         nsk = __inet6_lookup_established(sock_net(sk), &tcp_hashinfo,
1027                         &ipv6_hdr(skb)->saddr, th->source,
1028                         &ipv6_hdr(skb)->daddr, ntohs(th->dest), inet6_iif(skb));
1029
1030         if (nsk) {
1031                 if (nsk->sk_state != TCP_TIME_WAIT) {
1032                         bh_lock_sock(nsk);
1033                         return nsk;
1034                 }
1035                 inet_twsk_put(inet_twsk(nsk));
1036                 return NULL;
1037         }
1038
1039 #ifdef CONFIG_SYN_COOKIES
1040         if (!th->syn)
1041                 sk = cookie_v6_check(sk, skb);
1042 #endif
1043         return sk;
1044 }
1045
1046 /* FIXME: this is substantially similar to the ipv4 code.
1047  * Can some kind of merge be done? -- erics
1048  */
1049 static int tcp_v6_conn_request(struct sock *sk, struct sk_buff *skb)
1050 {
1051         struct tcp_extend_values tmp_ext;
1052         struct tcp_options_received tmp_opt;
1053         const u8 *hash_location;
1054         struct request_sock *req;
1055         struct inet6_request_sock *treq;
1056         struct ipv6_pinfo *np = inet6_sk(sk);
1057         struct tcp_sock *tp = tcp_sk(sk);
1058         __u32 isn = TCP_SKB_CB(skb)->when;
1059         struct dst_entry *dst = NULL;
1060         bool want_cookie = false;
1061
1062         if (skb->protocol == htons(ETH_P_IP))
1063                 return tcp_v4_conn_request(sk, skb);
1064
1065         if (!ipv6_unicast_destination(skb))
1066                 goto drop;
1067
1068         if (inet_csk_reqsk_queue_is_full(sk) && !isn) {
1069                 want_cookie = tcp_syn_flood_action(sk, skb, "TCPv6");
1070                 if (!want_cookie)
1071                         goto drop;
1072         }
1073
1074         if (sk_acceptq_is_full(sk) && inet_csk_reqsk_queue_young(sk) > 1)
1075                 goto drop;
1076
1077         req = inet6_reqsk_alloc(&tcp6_request_sock_ops);
1078         if (req == NULL)
1079                 goto drop;
1080
1081 #ifdef CONFIG_TCP_MD5SIG
1082         tcp_rsk(req)->af_specific = &tcp_request_sock_ipv6_ops;
1083 #endif
1084
1085         tcp_clear_options(&tmp_opt);
1086         tmp_opt.mss_clamp = IPV6_MIN_MTU - sizeof(struct tcphdr) - sizeof(struct ipv6hdr);
1087         tmp_opt.user_mss = tp->rx_opt.user_mss;
1088         tcp_parse_options(skb, &tmp_opt, &hash_location, 0);
1089
1090         if (tmp_opt.cookie_plus > 0 &&
1091             tmp_opt.saw_tstamp &&
1092             !tp->rx_opt.cookie_out_never &&
1093             (sysctl_tcp_cookie_size > 0 ||
1094              (tp->cookie_values != NULL &&
1095               tp->cookie_values->cookie_desired > 0))) {
1096                 u8 *c;
1097                 u32 *d;
1098                 u32 *mess = &tmp_ext.cookie_bakery[COOKIE_DIGEST_WORDS];
1099                 int l = tmp_opt.cookie_plus - TCPOLEN_COOKIE_BASE;
1100
1101                 if (tcp_cookie_generator(&tmp_ext.cookie_bakery[0]) != 0)
1102                         goto drop_and_free;
1103
1104                 /* Secret recipe starts with IP addresses */
1105                 d = (__force u32 *)&ipv6_hdr(skb)->daddr.s6_addr32[0];
1106                 *mess++ ^= *d++;
1107                 *mess++ ^= *d++;
1108                 *mess++ ^= *d++;
1109                 *mess++ ^= *d++;
1110                 d = (__force u32 *)&ipv6_hdr(skb)->saddr.s6_addr32[0];
1111                 *mess++ ^= *d++;
1112                 *mess++ ^= *d++;
1113                 *mess++ ^= *d++;
1114                 *mess++ ^= *d++;
1115
1116                 /* plus variable length Initiator Cookie */
1117                 c = (u8 *)mess;
1118                 while (l-- > 0)
1119                         *c++ ^= *hash_location++;
1120
1121                 want_cookie = false;    /* not our kind of cookie */
1122                 tmp_ext.cookie_out_never = 0; /* false */
1123                 tmp_ext.cookie_plus = tmp_opt.cookie_plus;
1124         } else if (!tp->rx_opt.cookie_in_always) {
1125                 /* redundant indications, but ensure initialization. */
1126                 tmp_ext.cookie_out_never = 1; /* true */
1127                 tmp_ext.cookie_plus = 0;
1128         } else {
1129                 goto drop_and_free;
1130         }
1131         tmp_ext.cookie_in_always = tp->rx_opt.cookie_in_always;
1132
1133         if (want_cookie && !tmp_opt.saw_tstamp)
1134                 tcp_clear_options(&tmp_opt);
1135
1136         tmp_opt.tstamp_ok = tmp_opt.saw_tstamp;
1137         tcp_openreq_init(req, &tmp_opt, skb);
1138
1139         treq = inet6_rsk(req);
1140         treq->rmt_addr = ipv6_hdr(skb)->saddr;
1141         treq->loc_addr = ipv6_hdr(skb)->daddr;
1142         if (!want_cookie || tmp_opt.tstamp_ok)
1143                 TCP_ECN_create_request(req, skb);
1144
1145         treq->iif = sk->sk_bound_dev_if;
1146
1147         /* So that link locals have meaning */
1148         if (!sk->sk_bound_dev_if &&
1149             ipv6_addr_type(&treq->rmt_addr) & IPV6_ADDR_LINKLOCAL)
1150                 treq->iif = inet6_iif(skb);
1151
1152         if (!isn) {
1153                 struct inet_peer *peer = NULL;
1154
1155                 if (ipv6_opt_accepted(sk, skb) ||
1156                     np->rxopt.bits.rxinfo || np->rxopt.bits.rxoinfo ||
1157                     np->rxopt.bits.rxhlim || np->rxopt.bits.rxohlim) {
1158                         atomic_inc(&skb->users);
1159                         treq->pktopts = skb;
1160                 }
1161
1162                 if (want_cookie) {
1163                         isn = cookie_v6_init_sequence(sk, skb, &req->mss);
1164                         req->cookie_ts = tmp_opt.tstamp_ok;
1165                         goto have_isn;
1166                 }
1167
1168                 /* VJ's idea. We save last timestamp seen
1169                  * from the destination in peer table, when entering
1170                  * state TIME-WAIT, and check against it before
1171                  * accepting new connection request.
1172                  *
1173                  * If "isn" is not zero, this request hit alive
1174                  * timewait bucket, so that all the necessary checks
1175                  * are made in the function processing timewait state.
1176                  */
1177                 if (tmp_opt.saw_tstamp &&
1178                     tcp_death_row.sysctl_tw_recycle &&
1179                     (dst = inet6_csk_route_req(sk, req)) != NULL &&
1180                     (peer = rt6_get_peer((struct rt6_info *)dst)) != NULL &&
1181                     ipv6_addr_equal((struct in6_addr *)peer->daddr.addr.a6,
1182                                     &treq->rmt_addr)) {
1183                         inet_peer_refcheck(peer);
1184                         if ((u32)get_seconds() - peer->tcp_ts_stamp < TCP_PAWS_MSL &&
1185                             (s32)(peer->tcp_ts - req->ts_recent) >
1186                                                         TCP_PAWS_WINDOW) {
1187                                 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_PAWSPASSIVEREJECTED);
1188                                 goto drop_and_release;
1189                         }
1190                 }
1191                 /* Kill the following clause, if you dislike this way. */
1192                 else if (!sysctl_tcp_syncookies &&
1193                          (sysctl_max_syn_backlog - inet_csk_reqsk_queue_len(sk) <
1194                           (sysctl_max_syn_backlog >> 2)) &&
1195                          (!peer || !peer->tcp_ts_stamp) &&
1196                          (!dst || !dst_metric(dst, RTAX_RTT))) {
1197                         /* Without syncookies last quarter of
1198                          * backlog is filled with destinations,
1199                          * proven to be alive.
1200                          * It means that we continue to communicate
1201                          * to destinations, already remembered
1202                          * to the moment of synflood.
1203                          */
1204                         LIMIT_NETDEBUG(KERN_DEBUG "TCP: drop open request from %pI6/%u\n",
1205                                        &treq->rmt_addr, ntohs(tcp_hdr(skb)->source));
1206                         goto drop_and_release;
1207                 }
1208
1209                 isn = tcp_v6_init_sequence(skb);
1210         }
1211 have_isn:
1212         tcp_rsk(req)->snt_isn = isn;
1213         tcp_rsk(req)->snt_synack = tcp_time_stamp;
1214
1215         security_inet_conn_request(sk, skb, req);
1216
1217         if (tcp_v6_send_synack(sk, req,
1218                                (struct request_values *)&tmp_ext,
1219                                skb_get_queue_mapping(skb)) ||
1220             want_cookie)
1221                 goto drop_and_free;
1222
1223         inet6_csk_reqsk_queue_hash_add(sk, req, TCP_TIMEOUT_INIT);
1224         return 0;
1225
1226 drop_and_release:
1227         dst_release(dst);
1228 drop_and_free:
1229         reqsk_free(req);
1230 drop:
1231         return 0; /* don't send reset */
1232 }
1233
1234 static struct sock * tcp_v6_syn_recv_sock(struct sock *sk, struct sk_buff *skb,
1235                                           struct request_sock *req,
1236                                           struct dst_entry *dst)
1237 {
1238         struct inet6_request_sock *treq;
1239         struct ipv6_pinfo *newnp, *np = inet6_sk(sk);
1240         struct tcp6_sock *newtcp6sk;
1241         struct inet_sock *newinet;
1242         struct tcp_sock *newtp;
1243         struct sock *newsk;
1244         struct ipv6_txoptions *opt;
1245 #ifdef CONFIG_TCP_MD5SIG
1246         struct tcp_md5sig_key *key;
1247 #endif
1248
1249         if (skb->protocol == htons(ETH_P_IP)) {
1250                 /*
1251                  *      v6 mapped
1252                  */
1253
1254                 newsk = tcp_v4_syn_recv_sock(sk, skb, req, dst);
1255
1256                 if (newsk == NULL)
1257                         return NULL;
1258
1259                 newtcp6sk = (struct tcp6_sock *)newsk;
1260                 inet_sk(newsk)->pinet6 = &newtcp6sk->inet6;
1261
1262                 newinet = inet_sk(newsk);
1263                 newnp = inet6_sk(newsk);
1264                 newtp = tcp_sk(newsk);
1265
1266                 memcpy(newnp, np, sizeof(struct ipv6_pinfo));
1267
1268                 ipv6_addr_set_v4mapped(newinet->inet_daddr, &newnp->daddr);
1269
1270                 ipv6_addr_set_v4mapped(newinet->inet_saddr, &newnp->saddr);
1271
1272                 newnp->rcv_saddr = newnp->saddr;
1273
1274                 inet_csk(newsk)->icsk_af_ops = &ipv6_mapped;
1275                 newsk->sk_backlog_rcv = tcp_v4_do_rcv;
1276 #ifdef CONFIG_TCP_MD5SIG
1277                 newtp->af_specific = &tcp_sock_ipv6_mapped_specific;
1278 #endif
1279
1280                 newnp->ipv6_ac_list = NULL;
1281                 newnp->ipv6_fl_list = NULL;
1282                 newnp->pktoptions  = NULL;
1283                 newnp->opt         = NULL;
1284                 newnp->mcast_oif   = inet6_iif(skb);
1285                 newnp->mcast_hops  = ipv6_hdr(skb)->hop_limit;
1286                 newnp->rcv_tclass  = ipv6_tclass(ipv6_hdr(skb));
1287
1288                 /*
1289                  * No need to charge this sock to the relevant IPv6 refcnt debug socks count
1290                  * here, tcp_create_openreq_child now does this for us, see the comment in
1291                  * that function for the gory details. -acme
1292                  */
1293
1294                 /* It is tricky place. Until this moment IPv4 tcp
1295                    worked with IPv6 icsk.icsk_af_ops.
1296                    Sync it now.
1297                  */
1298                 tcp_sync_mss(newsk, inet_csk(newsk)->icsk_pmtu_cookie);
1299
1300                 return newsk;
1301         }
1302
1303         treq = inet6_rsk(req);
1304         opt = np->opt;
1305
1306         if (sk_acceptq_is_full(sk))
1307                 goto out_overflow;
1308
1309         if (!dst) {
1310                 dst = inet6_csk_route_req(sk, req);
1311                 if (!dst)
1312                         goto out;
1313         }
1314
1315         newsk = tcp_create_openreq_child(sk, req, skb);
1316         if (newsk == NULL)
1317                 goto out_nonewsk;
1318
1319         /*
1320          * No need to charge this sock to the relevant IPv6 refcnt debug socks
1321          * count here, tcp_create_openreq_child now does this for us, see the
1322          * comment in that function for the gory details. -acme
1323          */
1324
1325         newsk->sk_gso_type = SKB_GSO_TCPV6;
1326         __ip6_dst_store(newsk, dst, NULL, NULL);
1327
1328         newtcp6sk = (struct tcp6_sock *)newsk;
1329         inet_sk(newsk)->pinet6 = &newtcp6sk->inet6;
1330
1331         newtp = tcp_sk(newsk);
1332         newinet = inet_sk(newsk);
1333         newnp = inet6_sk(newsk);
1334
1335         memcpy(newnp, np, sizeof(struct ipv6_pinfo));
1336
1337         newnp->daddr = treq->rmt_addr;
1338         newnp->saddr = treq->loc_addr;
1339         newnp->rcv_saddr = treq->loc_addr;
1340         newsk->sk_bound_dev_if = treq->iif;
1341
1342         /* Now IPv6 options...
1343
1344            First: no IPv4 options.
1345          */
1346         newinet->inet_opt = NULL;
1347         newnp->ipv6_ac_list = NULL;
1348         newnp->ipv6_fl_list = NULL;
1349
1350         /* Clone RX bits */
1351         newnp->rxopt.all = np->rxopt.all;
1352
1353         /* Clone pktoptions received with SYN */
1354         newnp->pktoptions = NULL;
1355         if (treq->pktopts != NULL) {
1356                 newnp->pktoptions = skb_clone(treq->pktopts, GFP_ATOMIC);
1357                 consume_skb(treq->pktopts);
1358                 treq->pktopts = NULL;
1359                 if (newnp->pktoptions)
1360                         skb_set_owner_r(newnp->pktoptions, newsk);
1361         }
1362         newnp->opt        = NULL;
1363         newnp->mcast_oif  = inet6_iif(skb);
1364         newnp->mcast_hops = ipv6_hdr(skb)->hop_limit;
1365         newnp->rcv_tclass = ipv6_tclass(ipv6_hdr(skb));
1366
1367         /* Clone native IPv6 options from listening socket (if any)
1368
1369            Yes, keeping reference count would be much more clever,
1370            but we make one more one thing there: reattach optmem
1371            to newsk.
1372          */
1373         if (opt) {
1374                 newnp->opt = ipv6_dup_options(newsk, opt);
1375                 if (opt != np->opt)
1376                         sock_kfree_s(sk, opt, opt->tot_len);
1377         }
1378
1379         inet_csk(newsk)->icsk_ext_hdr_len = 0;
1380         if (newnp->opt)
1381                 inet_csk(newsk)->icsk_ext_hdr_len = (newnp->opt->opt_nflen +
1382                                                      newnp->opt->opt_flen);
1383
1384         tcp_mtup_init(newsk);
1385         tcp_sync_mss(newsk, dst_mtu(dst));
1386         newtp->advmss = dst_metric_advmss(dst);
1387         if (tcp_sk(sk)->rx_opt.user_mss &&
1388             tcp_sk(sk)->rx_opt.user_mss < newtp->advmss)
1389                 newtp->advmss = tcp_sk(sk)->rx_opt.user_mss;
1390
1391         tcp_initialize_rcv_mss(newsk);
1392         if (tcp_rsk(req)->snt_synack)
1393                 tcp_valid_rtt_meas(newsk,
1394                     tcp_time_stamp - tcp_rsk(req)->snt_synack);
1395         newtp->total_retrans = req->retrans;
1396
1397         newinet->inet_daddr = newinet->inet_saddr = LOOPBACK4_IPV6;
1398         newinet->inet_rcv_saddr = LOOPBACK4_IPV6;
1399
1400 #ifdef CONFIG_TCP_MD5SIG
1401         /* Copy over the MD5 key from the original socket */
1402         if ((key = tcp_v6_md5_do_lookup(sk, &newnp->daddr)) != NULL) {
1403                 /* We're using one, so create a matching key
1404                  * on the newsk structure. If we fail to get
1405                  * memory, then we end up not copying the key
1406                  * across. Shucks.
1407                  */
1408                 tcp_md5_do_add(newsk, (union tcp_md5_addr *)&newnp->daddr,
1409                                AF_INET6, key->key, key->keylen, GFP_ATOMIC);
1410         }
1411 #endif
1412
1413         if (__inet_inherit_port(sk, newsk) < 0) {
1414                 sock_put(newsk);
1415                 goto out;
1416         }
1417         __inet6_hash(newsk, NULL);
1418
1419         return newsk;
1420
1421 out_overflow:
1422         NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
1423 out_nonewsk:
1424         if (opt && opt != np->opt)
1425                 sock_kfree_s(sk, opt, opt->tot_len);
1426         dst_release(dst);
1427 out:
1428         NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
1429         return NULL;
1430 }
1431
1432 static __sum16 tcp_v6_checksum_init(struct sk_buff *skb)
1433 {
1434         if (skb->ip_summed == CHECKSUM_COMPLETE) {
1435                 if (!tcp_v6_check(skb->len, &ipv6_hdr(skb)->saddr,
1436                                   &ipv6_hdr(skb)->daddr, skb->csum)) {
1437                         skb->ip_summed = CHECKSUM_UNNECESSARY;
1438                         return 0;
1439                 }
1440         }
1441
1442         skb->csum = ~csum_unfold(tcp_v6_check(skb->len,
1443                                               &ipv6_hdr(skb)->saddr,
1444                                               &ipv6_hdr(skb)->daddr, 0));
1445
1446         if (skb->len <= 76) {
1447                 return __skb_checksum_complete(skb);
1448         }
1449         return 0;
1450 }
1451
1452 /* The socket must have it's spinlock held when we get
1453  * here.
1454  *
1455  * We have a potential double-lock case here, so even when
1456  * doing backlog processing we use the BH locking scheme.
1457  * This is because we cannot sleep with the original spinlock
1458  * held.
1459  */
1460 static int tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb)
1461 {
1462         struct ipv6_pinfo *np = inet6_sk(sk);
1463         struct tcp_sock *tp;
1464         struct sk_buff *opt_skb = NULL;
1465
1466         /* Imagine: socket is IPv6. IPv4 packet arrives,
1467            goes to IPv4 receive handler and backlogged.
1468            From backlog it always goes here. Kerboom...
1469            Fortunately, tcp_rcv_established and rcv_established
1470            handle them correctly, but it is not case with
1471            tcp_v6_hnd_req and tcp_v6_send_reset().   --ANK
1472          */
1473
1474         if (skb->protocol == htons(ETH_P_IP))
1475                 return tcp_v4_do_rcv(sk, skb);
1476
1477 #ifdef CONFIG_TCP_MD5SIG
1478         if (tcp_v6_inbound_md5_hash (sk, skb))
1479                 goto discard;
1480 #endif
1481
1482         if (sk_filter(sk, skb))
1483                 goto discard;
1484
1485         /*
1486          *      socket locking is here for SMP purposes as backlog rcv
1487          *      is currently called with bh processing disabled.
1488          */
1489
1490         /* Do Stevens' IPV6_PKTOPTIONS.
1491
1492            Yes, guys, it is the only place in our code, where we
1493            may make it not affecting IPv4.
1494            The rest of code is protocol independent,
1495            and I do not like idea to uglify IPv4.
1496
1497            Actually, all the idea behind IPV6_PKTOPTIONS
1498            looks not very well thought. For now we latch
1499            options, received in the last packet, enqueued
1500            by tcp. Feel free to propose better solution.
1501                                                --ANK (980728)
1502          */
1503         if (np->rxopt.all)
1504                 opt_skb = skb_clone(skb, GFP_ATOMIC);
1505
1506         if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
1507                 sock_rps_save_rxhash(sk, skb);
1508                 if (tcp_rcv_established(sk, skb, tcp_hdr(skb), skb->len))
1509                         goto reset;
1510                 if (opt_skb)
1511                         goto ipv6_pktoptions;
1512                 return 0;
1513         }
1514
1515         if (skb->len < tcp_hdrlen(skb) || tcp_checksum_complete(skb))
1516                 goto csum_err;
1517
1518         if (sk->sk_state == TCP_LISTEN) {
1519                 struct sock *nsk = tcp_v6_hnd_req(sk, skb);
1520                 if (!nsk)
1521                         goto discard;
1522
1523                 /*
1524                  * Queue it on the new socket if the new socket is active,
1525                  * otherwise we just shortcircuit this and continue with
1526                  * the new socket..
1527                  */
1528                 if(nsk != sk) {
1529                         sock_rps_save_rxhash(nsk, skb);
1530                         if (tcp_child_process(sk, nsk, skb))
1531                                 goto reset;
1532                         if (opt_skb)
1533                                 __kfree_skb(opt_skb);
1534                         return 0;
1535                 }
1536         } else
1537                 sock_rps_save_rxhash(sk, skb);
1538
1539         if (tcp_rcv_state_process(sk, skb, tcp_hdr(skb), skb->len))
1540                 goto reset;
1541         if (opt_skb)
1542                 goto ipv6_pktoptions;
1543         return 0;
1544
1545 reset:
1546         tcp_v6_send_reset(sk, skb);
1547 discard:
1548         if (opt_skb)
1549                 __kfree_skb(opt_skb);
1550         kfree_skb(skb);
1551         return 0;
1552 csum_err:
1553         TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_INERRS);
1554         goto discard;
1555
1556
1557 ipv6_pktoptions:
1558         /* Do you ask, what is it?
1559
1560            1. skb was enqueued by tcp.
1561            2. skb is added to tail of read queue, rather than out of order.
1562            3. socket is not in passive state.
1563            4. Finally, it really contains options, which user wants to receive.
1564          */
1565         tp = tcp_sk(sk);
1566         if (TCP_SKB_CB(opt_skb)->end_seq == tp->rcv_nxt &&
1567             !((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN))) {
1568                 if (np->rxopt.bits.rxinfo || np->rxopt.bits.rxoinfo)
1569                         np->mcast_oif = inet6_iif(opt_skb);
1570                 if (np->rxopt.bits.rxhlim || np->rxopt.bits.rxohlim)
1571                         np->mcast_hops = ipv6_hdr(opt_skb)->hop_limit;
1572                 if (np->rxopt.bits.rxtclass)
1573                         np->rcv_tclass = ipv6_tclass(ipv6_hdr(skb));
1574                 if (ipv6_opt_accepted(sk, opt_skb)) {
1575                         skb_set_owner_r(opt_skb, sk);
1576                         opt_skb = xchg(&np->pktoptions, opt_skb);
1577                 } else {
1578                         __kfree_skb(opt_skb);
1579                         opt_skb = xchg(&np->pktoptions, NULL);
1580                 }
1581         }
1582
1583         kfree_skb(opt_skb);
1584         return 0;
1585 }
1586
1587 static int tcp_v6_rcv(struct sk_buff *skb)
1588 {
1589         const struct tcphdr *th;
1590         const struct ipv6hdr *hdr;
1591         struct sock *sk;
1592         int ret;
1593         struct net *net = dev_net(skb->dev);
1594
1595         if (skb->pkt_type != PACKET_HOST)
1596                 goto discard_it;
1597
1598         /*
1599          *      Count it even if it's bad.
1600          */
1601         TCP_INC_STATS_BH(net, TCP_MIB_INSEGS);
1602
1603         if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
1604                 goto discard_it;
1605
1606         th = tcp_hdr(skb);
1607
1608         if (th->doff < sizeof(struct tcphdr)/4)
1609                 goto bad_packet;
1610         if (!pskb_may_pull(skb, th->doff*4))
1611                 goto discard_it;
1612
1613         if (!skb_csum_unnecessary(skb) && tcp_v6_checksum_init(skb))
1614                 goto bad_packet;
1615
1616         th = tcp_hdr(skb);
1617         hdr = ipv6_hdr(skb);
1618         TCP_SKB_CB(skb)->seq = ntohl(th->seq);
1619         TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
1620                                     skb->len - th->doff*4);
1621         TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
1622         TCP_SKB_CB(skb)->when = 0;
1623         TCP_SKB_CB(skb)->ip_dsfield = ipv6_get_dsfield(hdr);
1624         TCP_SKB_CB(skb)->sacked = 0;
1625
1626         sk = __inet6_lookup_skb(&tcp_hashinfo, skb, th->source, th->dest);
1627         if (!sk)
1628                 goto no_tcp_socket;
1629
1630 process:
1631         if (sk->sk_state == TCP_TIME_WAIT)
1632                 goto do_time_wait;
1633
1634         if (hdr->hop_limit < inet6_sk(sk)->min_hopcount) {
1635                 NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP);
1636                 goto discard_and_relse;
1637         }
1638
1639         if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb))
1640                 goto discard_and_relse;
1641
1642         if (sk_filter(sk, skb))
1643                 goto discard_and_relse;
1644
1645         skb->dev = NULL;
1646
1647         bh_lock_sock_nested(sk);
1648         ret = 0;
1649         if (!sock_owned_by_user(sk)) {
1650 #ifdef CONFIG_NET_DMA
1651                 struct tcp_sock *tp = tcp_sk(sk);
1652                 if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list)
1653                         tp->ucopy.dma_chan = net_dma_find_channel();
1654                 if (tp->ucopy.dma_chan)
1655                         ret = tcp_v6_do_rcv(sk, skb);
1656                 else
1657 #endif
1658                 {
1659                         if (!tcp_prequeue(sk, skb))
1660                                 ret = tcp_v6_do_rcv(sk, skb);
1661                 }
1662         } else if (unlikely(sk_add_backlog(sk, skb,
1663                                            sk->sk_rcvbuf + sk->sk_sndbuf))) {
1664                 bh_unlock_sock(sk);
1665                 NET_INC_STATS_BH(net, LINUX_MIB_TCPBACKLOGDROP);
1666                 goto discard_and_relse;
1667         }
1668         bh_unlock_sock(sk);
1669
1670         sock_put(sk);
1671         return ret ? -1 : 0;
1672
1673 no_tcp_socket:
1674         if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb))
1675                 goto discard_it;
1676
1677         if (skb->len < (th->doff<<2) || tcp_checksum_complete(skb)) {
1678 bad_packet:
1679                 TCP_INC_STATS_BH(net, TCP_MIB_INERRS);
1680         } else {
1681                 tcp_v6_send_reset(NULL, skb);
1682         }
1683
1684 discard_it:
1685
1686         /*
1687          *      Discard frame
1688          */
1689
1690         kfree_skb(skb);
1691         return 0;
1692
1693 discard_and_relse:
1694         sock_put(sk);
1695         goto discard_it;
1696
1697 do_time_wait:
1698         if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
1699                 inet_twsk_put(inet_twsk(sk));
1700                 goto discard_it;
1701         }
1702
1703         if (skb->len < (th->doff<<2) || tcp_checksum_complete(skb)) {
1704                 TCP_INC_STATS_BH(net, TCP_MIB_INERRS);
1705                 inet_twsk_put(inet_twsk(sk));
1706                 goto discard_it;
1707         }
1708
1709         switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) {
1710         case TCP_TW_SYN:
1711         {
1712                 struct sock *sk2;
1713
1714                 sk2 = inet6_lookup_listener(dev_net(skb->dev), &tcp_hashinfo,
1715                                             &ipv6_hdr(skb)->daddr,
1716                                             ntohs(th->dest), inet6_iif(skb));
1717                 if (sk2 != NULL) {
1718                         struct inet_timewait_sock *tw = inet_twsk(sk);
1719                         inet_twsk_deschedule(tw, &tcp_death_row);
1720                         inet_twsk_put(tw);
1721                         sk = sk2;
1722                         goto process;
1723                 }
1724                 /* Fall through to ACK */
1725         }
1726         case TCP_TW_ACK:
1727                 tcp_v6_timewait_ack(sk, skb);
1728                 break;
1729         case TCP_TW_RST:
1730                 goto no_tcp_socket;
1731         case TCP_TW_SUCCESS:;
1732         }
1733         goto discard_it;
1734 }
1735
1736 static struct inet_peer *tcp_v6_get_peer(struct sock *sk, bool *release_it)
1737 {
1738         struct rt6_info *rt = (struct rt6_info *) __sk_dst_get(sk);
1739         struct ipv6_pinfo *np = inet6_sk(sk);
1740         struct inet_peer *peer;
1741
1742         if (!rt ||
1743             !ipv6_addr_equal(&np->daddr, &rt->rt6i_dst.addr)) {
1744                 peer = inet_getpeer_v6(&np->daddr, 1);
1745                 *release_it = true;
1746         } else {
1747                 if (!rt->rt6i_peer)
1748                         rt6_bind_peer(rt, 1);
1749                 peer = rt->rt6i_peer;
1750                 *release_it = false;
1751         }
1752
1753         return peer;
1754 }
1755
1756 static void *tcp_v6_tw_get_peer(struct sock *sk)
1757 {
1758         const struct inet6_timewait_sock *tw6 = inet6_twsk(sk);
1759         const struct inet_timewait_sock *tw = inet_twsk(sk);
1760
1761         if (tw->tw_family == AF_INET)
1762                 return tcp_v4_tw_get_peer(sk);
1763
1764         return inet_getpeer_v6(&tw6->tw_v6_daddr, 1);
1765 }
1766
1767 static struct timewait_sock_ops tcp6_timewait_sock_ops = {
1768         .twsk_obj_size  = sizeof(struct tcp6_timewait_sock),
1769         .twsk_unique    = tcp_twsk_unique,
1770         .twsk_destructor= tcp_twsk_destructor,
1771         .twsk_getpeer   = tcp_v6_tw_get_peer,
1772 };
1773
1774 static const struct inet_connection_sock_af_ops ipv6_specific = {
1775         .queue_xmit        = inet6_csk_xmit,
1776         .send_check        = tcp_v6_send_check,
1777         .rebuild_header    = inet6_sk_rebuild_header,
1778         .conn_request      = tcp_v6_conn_request,
1779         .syn_recv_sock     = tcp_v6_syn_recv_sock,
1780         .get_peer          = tcp_v6_get_peer,
1781         .net_header_len    = sizeof(struct ipv6hdr),
1782         .net_frag_header_len = sizeof(struct frag_hdr),
1783         .setsockopt        = ipv6_setsockopt,
1784         .getsockopt        = ipv6_getsockopt,
1785         .addr2sockaddr     = inet6_csk_addr2sockaddr,
1786         .sockaddr_len      = sizeof(struct sockaddr_in6),
1787         .bind_conflict     = inet6_csk_bind_conflict,
1788 #ifdef CONFIG_COMPAT
1789         .compat_setsockopt = compat_ipv6_setsockopt,
1790         .compat_getsockopt = compat_ipv6_getsockopt,
1791 #endif
1792 };
1793
1794 #ifdef CONFIG_TCP_MD5SIG
1795 static const struct tcp_sock_af_ops tcp_sock_ipv6_specific = {
1796         .md5_lookup     =       tcp_v6_md5_lookup,
1797         .calc_md5_hash  =       tcp_v6_md5_hash_skb,
1798         .md5_parse      =       tcp_v6_parse_md5_keys,
1799 };
1800 #endif
1801
1802 /*
1803  *      TCP over IPv4 via INET6 API
1804  */
1805
1806 static const struct inet_connection_sock_af_ops ipv6_mapped = {
1807         .queue_xmit        = ip_queue_xmit,
1808         .send_check        = tcp_v4_send_check,
1809         .rebuild_header    = inet_sk_rebuild_header,
1810         .conn_request      = tcp_v6_conn_request,
1811         .syn_recv_sock     = tcp_v6_syn_recv_sock,
1812         .get_peer          = tcp_v4_get_peer,
1813         .net_header_len    = sizeof(struct iphdr),
1814         .setsockopt        = ipv6_setsockopt,
1815         .getsockopt        = ipv6_getsockopt,
1816         .addr2sockaddr     = inet6_csk_addr2sockaddr,
1817         .sockaddr_len      = sizeof(struct sockaddr_in6),
1818         .bind_conflict     = inet6_csk_bind_conflict,
1819 #ifdef CONFIG_COMPAT
1820         .compat_setsockopt = compat_ipv6_setsockopt,
1821         .compat_getsockopt = compat_ipv6_getsockopt,
1822 #endif
1823 };
1824
1825 #ifdef CONFIG_TCP_MD5SIG
1826 static const struct tcp_sock_af_ops tcp_sock_ipv6_mapped_specific = {
1827         .md5_lookup     =       tcp_v4_md5_lookup,
1828         .calc_md5_hash  =       tcp_v4_md5_hash_skb,
1829         .md5_parse      =       tcp_v6_parse_md5_keys,
1830 };
1831 #endif
1832
1833 /* NOTE: A lot of things set to zero explicitly by call to
1834  *       sk_alloc() so need not be done here.
1835  */
1836 static int tcp_v6_init_sock(struct sock *sk)
1837 {
1838         struct inet_connection_sock *icsk = inet_csk(sk);
1839
1840         tcp_init_sock(sk);
1841
1842         icsk->icsk_af_ops = &ipv6_specific;
1843
1844 #ifdef CONFIG_TCP_MD5SIG
1845         tcp_sk(sk)->af_specific = &tcp_sock_ipv6_specific;
1846 #endif
1847
1848         return 0;
1849 }
1850
1851 static void tcp_v6_destroy_sock(struct sock *sk)
1852 {
1853         tcp_v4_destroy_sock(sk);
1854         inet6_destroy_sock(sk);
1855 }
1856
1857 #ifdef CONFIG_PROC_FS
1858 /* Proc filesystem TCPv6 sock list dumping. */
1859 static void get_openreq6(struct seq_file *seq,
1860                          const struct sock *sk, struct request_sock *req, int i, int uid)
1861 {
1862         int ttd = req->expires - jiffies;
1863         const struct in6_addr *src = &inet6_rsk(req)->loc_addr;
1864         const struct in6_addr *dest = &inet6_rsk(req)->rmt_addr;
1865
1866         if (ttd < 0)
1867                 ttd = 0;
1868
1869         seq_printf(seq,
1870                    "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
1871                    "%02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK\n",
1872                    i,
1873                    src->s6_addr32[0], src->s6_addr32[1],
1874                    src->s6_addr32[2], src->s6_addr32[3],
1875                    ntohs(inet_rsk(req)->loc_port),
1876                    dest->s6_addr32[0], dest->s6_addr32[1],
1877                    dest->s6_addr32[2], dest->s6_addr32[3],
1878                    ntohs(inet_rsk(req)->rmt_port),
1879                    TCP_SYN_RECV,
1880                    0,0, /* could print option size, but that is af dependent. */
1881                    1,   /* timers active (only the expire timer) */
1882                    jiffies_to_clock_t(ttd),
1883                    req->retrans,
1884                    uid,
1885                    0,  /* non standard timer */
1886                    0, /* open_requests have no inode */
1887                    0, req);
1888 }
1889
1890 static void get_tcp6_sock(struct seq_file *seq, struct sock *sp, int i)
1891 {
1892         const struct in6_addr *dest, *src;
1893         __u16 destp, srcp;
1894         int timer_active;
1895         unsigned long timer_expires;
1896         const struct inet_sock *inet = inet_sk(sp);
1897         const struct tcp_sock *tp = tcp_sk(sp);
1898         const struct inet_connection_sock *icsk = inet_csk(sp);
1899         const struct ipv6_pinfo *np = inet6_sk(sp);
1900
1901         dest  = &np->daddr;
1902         src   = &np->rcv_saddr;
1903         destp = ntohs(inet->inet_dport);
1904         srcp  = ntohs(inet->inet_sport);
1905
1906         if (icsk->icsk_pending == ICSK_TIME_RETRANS) {
1907                 timer_active    = 1;
1908                 timer_expires   = icsk->icsk_timeout;
1909         } else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
1910                 timer_active    = 4;
1911                 timer_expires   = icsk->icsk_timeout;
1912         } else if (timer_pending(&sp->sk_timer)) {
1913                 timer_active    = 2;
1914                 timer_expires   = sp->sk_timer.expires;
1915         } else {
1916                 timer_active    = 0;
1917                 timer_expires = jiffies;
1918         }
1919
1920         seq_printf(seq,
1921                    "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
1922                    "%02X %08X:%08X %02X:%08lX %08X %5d %8d %lu %d %pK %lu %lu %u %u %d\n",
1923                    i,
1924                    src->s6_addr32[0], src->s6_addr32[1],
1925                    src->s6_addr32[2], src->s6_addr32[3], srcp,
1926                    dest->s6_addr32[0], dest->s6_addr32[1],
1927                    dest->s6_addr32[2], dest->s6_addr32[3], destp,
1928                    sp->sk_state,
1929                    tp->write_seq-tp->snd_una,
1930                    (sp->sk_state == TCP_LISTEN) ? sp->sk_ack_backlog : (tp->rcv_nxt - tp->copied_seq),
1931                    timer_active,
1932                    jiffies_to_clock_t(timer_expires - jiffies),
1933                    icsk->icsk_retransmits,
1934                    sock_i_uid(sp),
1935                    icsk->icsk_probes_out,
1936                    sock_i_ino(sp),
1937                    atomic_read(&sp->sk_refcnt), sp,
1938                    jiffies_to_clock_t(icsk->icsk_rto),
1939                    jiffies_to_clock_t(icsk->icsk_ack.ato),
1940                    (icsk->icsk_ack.quick << 1 ) | icsk->icsk_ack.pingpong,
1941                    tp->snd_cwnd,
1942                    tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh
1943                    );
1944 }
1945
1946 static void get_timewait6_sock(struct seq_file *seq,
1947                                struct inet_timewait_sock *tw, int i)
1948 {
1949         const struct in6_addr *dest, *src;
1950         __u16 destp, srcp;
1951         const struct inet6_timewait_sock *tw6 = inet6_twsk((struct sock *)tw);
1952         int ttd = tw->tw_ttd - jiffies;
1953
1954         if (ttd < 0)
1955                 ttd = 0;
1956
1957         dest = &tw6->tw_v6_daddr;
1958         src  = &tw6->tw_v6_rcv_saddr;
1959         destp = ntohs(tw->tw_dport);
1960         srcp  = ntohs(tw->tw_sport);
1961
1962         seq_printf(seq,
1963                    "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
1964                    "%02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK\n",
1965                    i,
1966                    src->s6_addr32[0], src->s6_addr32[1],
1967                    src->s6_addr32[2], src->s6_addr32[3], srcp,
1968                    dest->s6_addr32[0], dest->s6_addr32[1],
1969                    dest->s6_addr32[2], dest->s6_addr32[3], destp,
1970                    tw->tw_substate, 0, 0,
1971                    3, jiffies_to_clock_t(ttd), 0, 0, 0, 0,
1972                    atomic_read(&tw->tw_refcnt), tw);
1973 }
1974
1975 static int tcp6_seq_show(struct seq_file *seq, void *v)
1976 {
1977         struct tcp_iter_state *st;
1978
1979         if (v == SEQ_START_TOKEN) {
1980                 seq_puts(seq,
1981                          "  sl  "
1982                          "local_address                         "
1983                          "remote_address                        "
1984                          "st tx_queue rx_queue tr tm->when retrnsmt"
1985                          "   uid  timeout inode\n");
1986                 goto out;
1987         }
1988         st = seq->private;
1989
1990         switch (st->state) {
1991         case TCP_SEQ_STATE_LISTENING:
1992         case TCP_SEQ_STATE_ESTABLISHED:
1993                 get_tcp6_sock(seq, v, st->num);
1994                 break;
1995         case TCP_SEQ_STATE_OPENREQ:
1996                 get_openreq6(seq, st->syn_wait_sk, v, st->num, st->uid);
1997                 break;
1998         case TCP_SEQ_STATE_TIME_WAIT:
1999                 get_timewait6_sock(seq, v, st->num);
2000                 break;
2001         }
2002 out:
2003         return 0;
2004 }
2005
2006 static const struct file_operations tcp6_afinfo_seq_fops = {
2007         .owner   = THIS_MODULE,
2008         .open    = tcp_seq_open,
2009         .read    = seq_read,
2010         .llseek  = seq_lseek,
2011         .release = seq_release_net
2012 };
2013
2014 static struct tcp_seq_afinfo tcp6_seq_afinfo = {
2015         .name           = "tcp6",
2016         .family         = AF_INET6,
2017         .seq_fops       = &tcp6_afinfo_seq_fops,
2018         .seq_ops        = {
2019                 .show           = tcp6_seq_show,
2020         },
2021 };
2022
2023 int __net_init tcp6_proc_init(struct net *net)
2024 {
2025         return tcp_proc_register(net, &tcp6_seq_afinfo);
2026 }
2027
2028 void tcp6_proc_exit(struct net *net)
2029 {
2030         tcp_proc_unregister(net, &tcp6_seq_afinfo);
2031 }
2032 #endif
2033
2034 struct proto tcpv6_prot = {
2035         .name                   = "TCPv6",
2036         .owner                  = THIS_MODULE,
2037         .close                  = tcp_close,
2038         .connect                = tcp_v6_connect,
2039         .disconnect             = tcp_disconnect,
2040         .accept                 = inet_csk_accept,
2041         .ioctl                  = tcp_ioctl,
2042         .init                   = tcp_v6_init_sock,
2043         .destroy                = tcp_v6_destroy_sock,
2044         .shutdown               = tcp_shutdown,
2045         .setsockopt             = tcp_setsockopt,
2046         .getsockopt             = tcp_getsockopt,
2047         .recvmsg                = tcp_recvmsg,
2048         .sendmsg                = tcp_sendmsg,
2049         .sendpage               = tcp_sendpage,
2050         .backlog_rcv            = tcp_v6_do_rcv,
2051         .hash                   = tcp_v6_hash,
2052         .unhash                 = inet_unhash,
2053         .get_port               = inet_csk_get_port,
2054         .enter_memory_pressure  = tcp_enter_memory_pressure,
2055         .sockets_allocated      = &tcp_sockets_allocated,
2056         .memory_allocated       = &tcp_memory_allocated,
2057         .memory_pressure        = &tcp_memory_pressure,
2058         .orphan_count           = &tcp_orphan_count,
2059         .sysctl_wmem            = sysctl_tcp_wmem,
2060         .sysctl_rmem            = sysctl_tcp_rmem,
2061         .max_header             = MAX_TCP_HEADER,
2062         .obj_size               = sizeof(struct tcp6_sock),
2063         .slab_flags             = SLAB_DESTROY_BY_RCU,
2064         .twsk_prot              = &tcp6_timewait_sock_ops,
2065         .rsk_prot               = &tcp6_request_sock_ops,
2066         .h.hashinfo             = &tcp_hashinfo,
2067         .no_autobind            = true,
2068 #ifdef CONFIG_COMPAT
2069         .compat_setsockopt      = compat_tcp_setsockopt,
2070         .compat_getsockopt      = compat_tcp_getsockopt,
2071 #endif
2072 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM
2073         .proto_cgroup           = tcp_proto_cgroup,
2074 #endif
2075 };
2076
2077 static const struct inet6_protocol tcpv6_protocol = {
2078         .handler        =       tcp_v6_rcv,
2079         .err_handler    =       tcp_v6_err,
2080         .gso_send_check =       tcp_v6_gso_send_check,
2081         .gso_segment    =       tcp_tso_segment,
2082         .gro_receive    =       tcp6_gro_receive,
2083         .gro_complete   =       tcp6_gro_complete,
2084         .flags          =       INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
2085 };
2086
2087 static struct inet_protosw tcpv6_protosw = {
2088         .type           =       SOCK_STREAM,
2089         .protocol       =       IPPROTO_TCP,
2090         .prot           =       &tcpv6_prot,
2091         .ops            =       &inet6_stream_ops,
2092         .no_check       =       0,
2093         .flags          =       INET_PROTOSW_PERMANENT |
2094                                 INET_PROTOSW_ICSK,
2095 };
2096
2097 static int __net_init tcpv6_net_init(struct net *net)
2098 {
2099         return inet_ctl_sock_create(&net->ipv6.tcp_sk, PF_INET6,
2100                                     SOCK_RAW, IPPROTO_TCP, net);
2101 }
2102
2103 static void __net_exit tcpv6_net_exit(struct net *net)
2104 {
2105         inet_ctl_sock_destroy(net->ipv6.tcp_sk);
2106 }
2107
2108 static void __net_exit tcpv6_net_exit_batch(struct list_head *net_exit_list)
2109 {
2110         inet_twsk_purge(&tcp_hashinfo, &tcp_death_row, AF_INET6);
2111 }
2112
2113 static struct pernet_operations tcpv6_net_ops = {
2114         .init       = tcpv6_net_init,
2115         .exit       = tcpv6_net_exit,
2116         .exit_batch = tcpv6_net_exit_batch,
2117 };
2118
2119 int __init tcpv6_init(void)
2120 {
2121         int ret;
2122
2123         ret = inet6_add_protocol(&tcpv6_protocol, IPPROTO_TCP);
2124         if (ret)
2125                 goto out;
2126
2127         /* register inet6 protocol */
2128         ret = inet6_register_protosw(&tcpv6_protosw);
2129         if (ret)
2130                 goto out_tcpv6_protocol;
2131
2132         ret = register_pernet_subsys(&tcpv6_net_ops);
2133         if (ret)
2134                 goto out_tcpv6_protosw;
2135 out:
2136         return ret;
2137
2138 out_tcpv6_protocol:
2139         inet6_del_protocol(&tcpv6_protocol, IPPROTO_TCP);
2140 out_tcpv6_protosw:
2141         inet6_unregister_protosw(&tcpv6_protosw);
2142         goto out;
2143 }
2144
2145 void tcpv6_exit(void)
2146 {
2147         unregister_pernet_subsys(&tcpv6_net_ops);
2148         inet6_unregister_protosw(&tcpv6_protosw);
2149         inet6_del_protocol(&tcpv6_protocol, IPPROTO_TCP);
2150 }