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 {
 481         struct inet6_request_sock *treq = inet6_rsk(req);
 482         struct ipv6_pinfo *np = inet6_sk(sk);
 483         struct sk_buff * skb;
 484         struct ipv6_txoptions *opt = NULL;
 485         struct in6_addr * final_p, final;
 486         struct flowi6 fl6;
 487         struct dst_entry *dst;
 488         int err;
 489
 490         memset(&fl6, 0, sizeof(fl6));
 491         fl6.flowi6_proto = IPPROTO_TCP;
 492         fl6.daddr = treq->rmt_addr;
 493         fl6.saddr = treq->loc_addr;
 494         fl6.flowlabel = 0;
 495         fl6.flowi6_oif = treq->iif;
 496         fl6.flowi6_mark = sk->sk_mark;
 497         fl6.fl6_dport = inet_rsk(req)->rmt_port;
 498         fl6.fl6_sport = inet_rsk(req)->loc_port;
 499         security_req_classify_flow(req, flowi6_to_flowi(&fl6));
 500
 501         opt = np->opt;
 502         final_p = fl6_update_dst(&fl6, opt, &final);
 503
 504         dst = ip6_dst_lookup_flow(sk, &fl6, final_p, false);
 505         if (IS_ERR(dst)) {
 506                 err = PTR_ERR(dst);
 507                 dst = NULL;
 508                 goto done;
 509         }
 510         skb = tcp_make_synack(sk, dst, req, rvp);
 511         err = -ENOMEM;
 512         if (skb) {
 513                 __tcp_v6_send_check(skb, &treq->loc_addr, &treq->rmt_addr);
 514
 515                 fl6.daddr = treq->rmt_addr;
 516                 err = ip6_xmit(sk, skb, &fl6, opt, np->tclass);
 517                 err = net_xmit_eval(err);
 518         }
 519
 520 done:
 521         if (opt && opt != np->opt)
 522                 sock_kfree_s(sk, opt, opt->tot_len);
 523         dst_release(dst);
 524         return err;
 525 }
 526
 527 static int tcp_v6_rtx_synack(struct sock *sk, struct request_sock *req,
 528                              struct request_values *rvp)
 529 {
 530         TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_RETRANSSEGS);
 531         return tcp_v6_send_synack(sk, req, rvp);
 532 }
 533
 534 static void tcp_v6_reqsk_destructor(struct request_sock *req)
 535 {
 536         kfree_skb(inet6_rsk(req)->pktopts);
 537 }
 538
 539 #ifdef CONFIG_TCP_MD5SIG
 540 static struct tcp_md5sig_key *tcp_v6_md5_do_lookup(struct sock *sk,
 541                                                    const struct in6_addr *addr)
 542 {
 543         return tcp_md5_do_lookup(sk, (union tcp_md5_addr *)addr, AF_INET6);
 544 }
 545
 546 static struct tcp_md5sig_key *tcp_v6_md5_lookup(struct sock *sk,
 547                                                 struct sock *addr_sk)
 548 {
 549         return tcp_v6_md5_do_lookup(sk, &inet6_sk(addr_sk)->daddr);
 550 }
 551
 552 static struct tcp_md5sig_key *tcp_v6_reqsk_md5_lookup(struct sock *sk,
 553                                                       struct request_sock *req)
 554 {
 555         return tcp_v6_md5_do_lookup(sk, &inet6_rsk(req)->rmt_addr);
 556 }
 557
 558 static int tcp_v6_parse_md5_keys (struct sock *sk, char __user *optval,
 559                                   int optlen)
 560 {
 561         struct tcp_md5sig cmd;
 562         struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)&cmd.tcpm_addr;
 563
 564         if (optlen < sizeof(cmd))
 565                 return -EINVAL;
 566
 567         if (copy_from_user(&cmd, optval, sizeof(cmd)))
 568                 return -EFAULT;
 569
 570         if (sin6->sin6_family != AF_INET6)
 571                 return -EINVAL;
 572
 573         if (!cmd.tcpm_keylen) {
 574                 if (ipv6_addr_v4mapped(&sin6->sin6_addr))
 575                         return tcp_md5_do_del(sk, (union tcp_md5_addr *)&sin6->sin6_addr.s6_addr32[3],
 576                                               AF_INET);
 577                 return tcp_md5_do_del(sk, (union tcp_md5_addr *)&sin6->sin6_addr,
 578                                       AF_INET6);
 579         }
 580
 581         if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN)
 582                 return -EINVAL;
 583
 584         if (ipv6_addr_v4mapped(&sin6->sin6_addr))
 585                 return tcp_md5_do_add(sk, (union tcp_md5_addr *)&sin6->sin6_addr.s6_addr32[3],
 586                                       AF_INET, cmd.tcpm_key, cmd.tcpm_keylen, GFP_KERNEL);
 587
 588         return tcp_md5_do_add(sk, (union tcp_md5_addr *)&sin6->sin6_addr,
 589                               AF_INET6, cmd.tcpm_key, cmd.tcpm_keylen, GFP_KERNEL);
 590 }
 591
 592 static int tcp_v6_md5_hash_pseudoheader(struct tcp_md5sig_pool *hp,
 593                                         const struct in6_addr *daddr,
 594                                         const struct in6_addr *saddr, int nbytes)
 595 {
 596         struct tcp6_pseudohdr *bp;
 597         struct scatterlist sg;
 598
 599         bp = &hp->md5_blk.ip6;
 600         /* 1. TCP pseudo-header (RFC2460) */
 601         bp->saddr = *saddr;
 602         bp->daddr = *daddr;
 603         bp->protocol = cpu_to_be32(IPPROTO_TCP);
 604         bp->len = cpu_to_be32(nbytes);
 605
 606         sg_init_one(&sg, bp, sizeof(*bp));
 607         return crypto_hash_update(&hp->md5_desc, &sg, sizeof(*bp));
 608 }
 609
 610 static int tcp_v6_md5_hash_hdr(char *md5_hash, struct tcp_md5sig_key *key,
 611                                const struct in6_addr *daddr, struct in6_addr *saddr,
 612                                const struct tcphdr *th)
 613 {
 614         struct tcp_md5sig_pool *hp;
 615         struct hash_desc *desc;
 616
 617         hp = tcp_get_md5sig_pool();
 618         if (!hp)
 619                 goto clear_hash_noput;
 620         desc = &hp->md5_desc;
 621
 622         if (crypto_hash_init(desc))
 623                 goto clear_hash;
 624         if (tcp_v6_md5_hash_pseudoheader(hp, daddr, saddr, th->doff << 2))
 625                 goto clear_hash;
 626         if (tcp_md5_hash_header(hp, th))
 627                 goto clear_hash;
 628         if (tcp_md5_hash_key(hp, key))
 629                 goto clear_hash;
 630         if (crypto_hash_final(desc, md5_hash))
 631                 goto clear_hash;
 632
 633         tcp_put_md5sig_pool();
 634         return 0;
 635
 636 clear_hash:
 637         tcp_put_md5sig_pool();
 638 clear_hash_noput:
 639         memset(md5_hash, 0, 16);
 640         return 1;
 641 }
 642
 643 static int tcp_v6_md5_hash_skb(char *md5_hash, struct tcp_md5sig_key *key,
 644                                const struct sock *sk,
 645                                const struct request_sock *req,
 646                                const struct sk_buff *skb)
 647 {
 648         const struct in6_addr *saddr, *daddr;
 649         struct tcp_md5sig_pool *hp;
 650         struct hash_desc *desc;
 651         const struct tcphdr *th = tcp_hdr(skb);
 652
 653         if (sk) {
 654                 saddr = &inet6_sk(sk)->saddr;
 655                 daddr = &inet6_sk(sk)->daddr;
 656         } else if (req) {
 657                 saddr = &inet6_rsk(req)->loc_addr;
 658                 daddr = &inet6_rsk(req)->rmt_addr;
 659         } else {
 660                 const struct ipv6hdr *ip6h = ipv6_hdr(skb);
 661                 saddr = &ip6h->saddr;
 662                 daddr = &ip6h->daddr;
 663         }
 664
 665         hp = tcp_get_md5sig_pool();
 666         if (!hp)
 667                 goto clear_hash_noput;
 668         desc = &hp->md5_desc;
 669
 670         if (crypto_hash_init(desc))
 671                 goto clear_hash;
 672
 673         if (tcp_v6_md5_hash_pseudoheader(hp, daddr, saddr, skb->len))
 674                 goto clear_hash;
 675         if (tcp_md5_hash_header(hp, th))
 676                 goto clear_hash;
 677         if (tcp_md5_hash_skb_data(hp, skb, th->doff << 2))
 678                 goto clear_hash;
 679         if (tcp_md5_hash_key(hp, key))
 680                 goto clear_hash;
 681         if (crypto_hash_final(desc, md5_hash))
 682                 goto clear_hash;
 683
 684         tcp_put_md5sig_pool();
 685         return 0;
 686
 687 clear_hash:
 688         tcp_put_md5sig_pool();
 689 clear_hash_noput:
 690         memset(md5_hash, 0, 16);
 691         return 1;
 692 }
 693
 694 static int tcp_v6_inbound_md5_hash(struct sock *sk, const struct sk_buff *skb)
 695 {
 696         const __u8 *hash_location = NULL;
 697         struct tcp_md5sig_key *hash_expected;
 698         const struct ipv6hdr *ip6h = ipv6_hdr(skb);
 699         const struct tcphdr *th = tcp_hdr(skb);
 700         int genhash;
 701         u8 newhash[16];
 702
 703         hash_expected = tcp_v6_md5_do_lookup(sk, &ip6h->saddr);
 704         hash_location = tcp_parse_md5sig_option(th);
 705
 706         /* We've parsed the options - do we have a hash? */
 707         if (!hash_expected && !hash_location)
 708                 return 0;
 709
 710         if (hash_expected && !hash_location) {
 711                 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5NOTFOUND);
 712                 return 1;
 713         }
 714
 715         if (!hash_expected && hash_location) {
 716                 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5UNEXPECTED);
 717                 return 1;
 718         }
 719
 720         /* check the signature */
 721         genhash = tcp_v6_md5_hash_skb(newhash,
 722                                       hash_expected,
 723                                       NULL, NULL, skb);
 724
 725         if (genhash || memcmp(hash_location, newhash, 16) != 0) {
 726                 if (net_ratelimit()) {
 727                         printk(KERN_INFO "MD5 Hash %s for [%pI6c]:%u->[%pI6c]:%u\n",
 728                                genhash ? "failed" : "mismatch",
 729                                &ip6h->saddr, ntohs(th->source),
 730                                &ip6h->daddr, ntohs(th->dest));
 731                 }
 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         int want_cookie = 0;
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 = 0;        /* 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, tcp_hdr(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             want_cookie)
1220                 goto drop_and_free;
1221
1222         inet6_csk_reqsk_queue_hash_add(sk, req, TCP_TIMEOUT_INIT);
1223         return 0;
1224
1225 drop_and_release:
1226         dst_release(dst);
1227 drop_and_free:
1228         reqsk_free(req);
1229 drop:
1230         return 0; /* don't send reset */
1231 }
1232
1233 static struct sock * tcp_v6_syn_recv_sock(struct sock *sk, struct sk_buff *skb,
1234                                           struct request_sock *req,
1235                                           struct dst_entry *dst)
1236 {
1237         struct inet6_request_sock *treq;
1238         struct ipv6_pinfo *newnp, *np = inet6_sk(sk);
1239         struct tcp6_sock *newtcp6sk;
1240         struct inet_sock *newinet;
1241         struct tcp_sock *newtp;
1242         struct sock *newsk;
1243         struct ipv6_txoptions *opt;
1244 #ifdef CONFIG_TCP_MD5SIG
1245         struct tcp_md5sig_key *key;
1246 #endif
1247
1248         if (skb->protocol == htons(ETH_P_IP)) {
1249                 /*
1250                  *      v6 mapped
1251                  */
1252
1253                 newsk = tcp_v4_syn_recv_sock(sk, skb, req, dst);
1254
1255                 if (newsk == NULL)
1256                         return NULL;
1257
1258                 newtcp6sk = (struct tcp6_sock *)newsk;
1259                 inet_sk(newsk)->pinet6 = &newtcp6sk->inet6;
1260
1261                 newinet = inet_sk(newsk);
1262                 newnp = inet6_sk(newsk);
1263                 newtp = tcp_sk(newsk);
1264
1265                 memcpy(newnp, np, sizeof(struct ipv6_pinfo));
1266
1267                 ipv6_addr_set_v4mapped(newinet->inet_daddr, &newnp->daddr);
1268
1269                 ipv6_addr_set_v4mapped(newinet->inet_saddr, &newnp->saddr);
1270
1271                 newnp->rcv_saddr = newnp->saddr;
1272
1273                 inet_csk(newsk)->icsk_af_ops = &ipv6_mapped;
1274                 newsk->sk_backlog_rcv = tcp_v4_do_rcv;
1275 #ifdef CONFIG_TCP_MD5SIG
1276                 newtp->af_specific = &tcp_sock_ipv6_mapped_specific;
1277 #endif
1278
1279                 newnp->ipv6_ac_list = NULL;
1280                 newnp->ipv6_fl_list = NULL;
1281                 newnp->pktoptions  = NULL;
1282                 newnp->opt         = NULL;
1283                 newnp->mcast_oif   = inet6_iif(skb);
1284                 newnp->mcast_hops  = ipv6_hdr(skb)->hop_limit;
1285                 newnp->rcv_tclass  = ipv6_tclass(ipv6_hdr(skb));
1286
1287                 /*
1288                  * No need to charge this sock to the relevant IPv6 refcnt debug socks count
1289                  * here, tcp_create_openreq_child now does this for us, see the comment in
1290                  * that function for the gory details. -acme
1291                  */
1292
1293                 /* It is tricky place. Until this moment IPv4 tcp
1294                    worked with IPv6 icsk.icsk_af_ops.
1295                    Sync it now.
1296                  */
1297                 tcp_sync_mss(newsk, inet_csk(newsk)->icsk_pmtu_cookie);
1298
1299                 return newsk;
1300         }
1301
1302         treq = inet6_rsk(req);
1303         opt = np->opt;
1304
1305         if (sk_acceptq_is_full(sk))
1306                 goto out_overflow;
1307
1308         if (!dst) {
1309                 dst = inet6_csk_route_req(sk, req);
1310                 if (!dst)
1311                         goto out;
1312         }
1313
1314         newsk = tcp_create_openreq_child(sk, req, skb);
1315         if (newsk == NULL)
1316                 goto out_nonewsk;
1317
1318         /*
1319          * No need to charge this sock to the relevant IPv6 refcnt debug socks
1320          * count here, tcp_create_openreq_child now does this for us, see the
1321          * comment in that function for the gory details. -acme
1322          */
1323
1324         newsk->sk_gso_type = SKB_GSO_TCPV6;
1325         __ip6_dst_store(newsk, dst, NULL, NULL);
1326
1327         newtcp6sk = (struct tcp6_sock *)newsk;
1328         inet_sk(newsk)->pinet6 = &newtcp6sk->inet6;
1329
1330         newtp = tcp_sk(newsk);
1331         newinet = inet_sk(newsk);
1332         newnp = inet6_sk(newsk);
1333
1334         memcpy(newnp, np, sizeof(struct ipv6_pinfo));
1335
1336         newnp->daddr = treq->rmt_addr;
1337         newnp->saddr = treq->loc_addr;
1338         newnp->rcv_saddr = treq->loc_addr;
1339         newsk->sk_bound_dev_if = treq->iif;
1340
1341         /* Now IPv6 options...
1342
1343            First: no IPv4 options.
1344          */
1345         newinet->inet_opt = NULL;
1346         newnp->ipv6_ac_list = NULL;
1347         newnp->ipv6_fl_list = NULL;
1348
1349         /* Clone RX bits */
1350         newnp->rxopt.all = np->rxopt.all;
1351
1352         /* Clone pktoptions received with SYN */
1353         newnp->pktoptions = NULL;
1354         if (treq->pktopts != NULL) {
1355                 newnp->pktoptions = skb_clone(treq->pktopts, GFP_ATOMIC);
1356                 kfree_skb(treq->pktopts);
1357                 treq->pktopts = NULL;
1358                 if (newnp->pktoptions)
1359                         skb_set_owner_r(newnp->pktoptions, newsk);
1360         }
1361         newnp->opt        = NULL;
1362         newnp->mcast_oif  = inet6_iif(skb);
1363         newnp->mcast_hops = ipv6_hdr(skb)->hop_limit;
1364         newnp->rcv_tclass = ipv6_tclass(ipv6_hdr(skb));
1365
1366         /* Clone native IPv6 options from listening socket (if any)
1367
1368            Yes, keeping reference count would be much more clever,
1369            but we make one more one thing there: reattach optmem
1370            to newsk.
1371          */
1372         if (opt) {
1373                 newnp->opt = ipv6_dup_options(newsk, opt);
1374                 if (opt != np->opt)
1375                         sock_kfree_s(sk, opt, opt->tot_len);
1376         }
1377
1378         inet_csk(newsk)->icsk_ext_hdr_len = 0;
1379         if (newnp->opt)
1380                 inet_csk(newsk)->icsk_ext_hdr_len = (newnp->opt->opt_nflen +
1381                                                      newnp->opt->opt_flen);
1382
1383         tcp_mtup_init(newsk);
1384         tcp_sync_mss(newsk, dst_mtu(dst));
1385         newtp->advmss = dst_metric_advmss(dst);
1386         if (tcp_sk(sk)->rx_opt.user_mss &&
1387             tcp_sk(sk)->rx_opt.user_mss < newtp->advmss)
1388                 newtp->advmss = tcp_sk(sk)->rx_opt.user_mss;
1389
1390         tcp_initialize_rcv_mss(newsk);
1391         if (tcp_rsk(req)->snt_synack)
1392                 tcp_valid_rtt_meas(newsk,
1393                     tcp_time_stamp - tcp_rsk(req)->snt_synack);
1394         newtp->total_retrans = req->retrans;
1395
1396         newinet->inet_daddr = newinet->inet_saddr = LOOPBACK4_IPV6;
1397         newinet->inet_rcv_saddr = LOOPBACK4_IPV6;
1398
1399 #ifdef CONFIG_TCP_MD5SIG
1400         /* Copy over the MD5 key from the original socket */
1401         if ((key = tcp_v6_md5_do_lookup(sk, &newnp->daddr)) != NULL) {
1402                 /* We're using one, so create a matching key
1403                  * on the newsk structure. If we fail to get
1404                  * memory, then we end up not copying the key
1405                  * across. Shucks.
1406                  */
1407                 tcp_md5_do_add(newsk, (union tcp_md5_addr *)&newnp->daddr,
1408                                AF_INET6, key->key, key->keylen, GFP_ATOMIC);
1409         }
1410 #endif
1411
1412         if (__inet_inherit_port(sk, newsk) < 0) {
1413                 sock_put(newsk);
1414                 goto out;
1415         }
1416         __inet6_hash(newsk, NULL);
1417
1418         return newsk;
1419
1420 out_overflow:
1421         NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
1422 out_nonewsk:
1423         if (opt && opt != np->opt)
1424                 sock_kfree_s(sk, opt, opt->tot_len);
1425         dst_release(dst);
1426 out:
1427         NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
1428         return NULL;
1429 }
1430
1431 static __sum16 tcp_v6_checksum_init(struct sk_buff *skb)
1432 {
1433         if (skb->ip_summed == CHECKSUM_COMPLETE) {
1434                 if (!tcp_v6_check(skb->len, &ipv6_hdr(skb)->saddr,
1435                                   &ipv6_hdr(skb)->daddr, skb->csum)) {
1436                         skb->ip_summed = CHECKSUM_UNNECESSARY;
1437                         return 0;
1438                 }
1439         }
1440
1441         skb->csum = ~csum_unfold(tcp_v6_check(skb->len,
1442                                               &ipv6_hdr(skb)->saddr,
1443                                               &ipv6_hdr(skb)->daddr, 0));
1444
1445         if (skb->len <= 76) {
1446                 return __skb_checksum_complete(skb);
1447         }
1448         return 0;
1449 }
1450
1451 /* The socket must have it's spinlock held when we get
1452  * here.
1453  *
1454  * We have a potential double-lock case here, so even when
1455  * doing backlog processing we use the BH locking scheme.
1456  * This is because we cannot sleep with the original spinlock
1457  * held.
1458  */
1459 static int tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb)
1460 {
1461         struct ipv6_pinfo *np = inet6_sk(sk);
1462         struct tcp_sock *tp;
1463         struct sk_buff *opt_skb = NULL;
1464
1465         /* Imagine: socket is IPv6. IPv4 packet arrives,
1466            goes to IPv4 receive handler and backlogged.
1467            From backlog it always goes here. Kerboom...
1468            Fortunately, tcp_rcv_established and rcv_established
1469            handle them correctly, but it is not case with
1470            tcp_v6_hnd_req and tcp_v6_send_reset().   --ANK
1471          */
1472
1473         if (skb->protocol == htons(ETH_P_IP))
1474                 return tcp_v4_do_rcv(sk, skb);
1475
1476 #ifdef CONFIG_TCP_MD5SIG
1477         if (tcp_v6_inbound_md5_hash (sk, skb))
1478                 goto discard;
1479 #endif
1480
1481         if (sk_filter(sk, skb))
1482                 goto discard;
1483
1484         /*
1485          *      socket locking is here for SMP purposes as backlog rcv
1486          *      is currently called with bh processing disabled.
1487          */
1488
1489         /* Do Stevens' IPV6_PKTOPTIONS.
1490
1491            Yes, guys, it is the only place in our code, where we
1492            may make it not affecting IPv4.
1493            The rest of code is protocol independent,
1494            and I do not like idea to uglify IPv4.
1495
1496            Actually, all the idea behind IPV6_PKTOPTIONS
1497            looks not very well thought. For now we latch
1498            options, received in the last packet, enqueued
1499            by tcp. Feel free to propose better solution.
1500                                                --ANK (980728)
1501          */
1502         if (np->rxopt.all)
1503                 opt_skb = skb_clone(skb, GFP_ATOMIC);
1504
1505         if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
1506                 sock_rps_save_rxhash(sk, skb);
1507                 if (tcp_rcv_established(sk, skb, tcp_hdr(skb), skb->len))
1508                         goto reset;
1509                 if (opt_skb)
1510                         goto ipv6_pktoptions;
1511                 return 0;
1512         }
1513
1514         if (skb->len < tcp_hdrlen(skb) || tcp_checksum_complete(skb))
1515                 goto csum_err;
1516
1517         if (sk->sk_state == TCP_LISTEN) {
1518                 struct sock *nsk = tcp_v6_hnd_req(sk, skb);
1519                 if (!nsk)
1520                         goto discard;
1521
1522                 /*
1523                  * Queue it on the new socket if the new socket is active,
1524                  * otherwise we just shortcircuit this and continue with
1525                  * the new socket..
1526                  */
1527                 if(nsk != sk) {
1528                         sock_rps_save_rxhash(nsk, skb);
1529                         if (tcp_child_process(sk, nsk, skb))
1530                                 goto reset;
1531                         if (opt_skb)
1532                                 __kfree_skb(opt_skb);
1533                         return 0;
1534                 }
1535         } else
1536                 sock_rps_save_rxhash(sk, skb);
1537
1538         if (tcp_rcv_state_process(sk, skb, tcp_hdr(skb), skb->len))
1539                 goto reset;
1540         if (opt_skb)
1541                 goto ipv6_pktoptions;
1542         return 0;
1543
1544 reset:
1545         tcp_v6_send_reset(sk, skb);
1546 discard:
1547         if (opt_skb)
1548                 __kfree_skb(opt_skb);
1549         kfree_skb(skb);
1550         return 0;
1551 csum_err:
1552         TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_INERRS);
1553         goto discard;
1554
1555
1556 ipv6_pktoptions:
1557         /* Do you ask, what is it?
1558
1559            1. skb was enqueued by tcp.
1560            2. skb is added to tail of read queue, rather than out of order.
1561            3. socket is not in passive state.
1562            4. Finally, it really contains options, which user wants to receive.
1563          */
1564         tp = tcp_sk(sk);
1565         if (TCP_SKB_CB(opt_skb)->end_seq == tp->rcv_nxt &&
1566             !((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN))) {
1567                 if (np->rxopt.bits.rxinfo || np->rxopt.bits.rxoinfo)
1568                         np->mcast_oif = inet6_iif(opt_skb);
1569                 if (np->rxopt.bits.rxhlim || np->rxopt.bits.rxohlim)
1570                         np->mcast_hops = ipv6_hdr(opt_skb)->hop_limit;
1571                 if (np->rxopt.bits.rxtclass)
1572                         np->rcv_tclass = ipv6_tclass(ipv6_hdr(skb));
1573                 if (ipv6_opt_accepted(sk, opt_skb)) {
1574                         skb_set_owner_r(opt_skb, sk);
1575                         opt_skb = xchg(&np->pktoptions, opt_skb);
1576                 } else {
1577                         __kfree_skb(opt_skb);
1578                         opt_skb = xchg(&np->pktoptions, NULL);
1579                 }
1580         }
1581
1582         kfree_skb(opt_skb);
1583         return 0;
1584 }
1585
1586 static int tcp_v6_rcv(struct sk_buff *skb)
1587 {
1588         const struct tcphdr *th;
1589         const struct ipv6hdr *hdr;
1590         struct sock *sk;
1591         int ret;
1592         struct net *net = dev_net(skb->dev);
1593
1594         if (skb->pkt_type != PACKET_HOST)
1595                 goto discard_it;
1596
1597         /*
1598          *      Count it even if it's bad.
1599          */
1600         TCP_INC_STATS_BH(net, TCP_MIB_INSEGS);
1601
1602         if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
1603                 goto discard_it;
1604
1605         th = tcp_hdr(skb);
1606
1607         if (th->doff < sizeof(struct tcphdr)/4)
1608                 goto bad_packet;
1609         if (!pskb_may_pull(skb, th->doff*4))
1610                 goto discard_it;
1611
1612         if (!skb_csum_unnecessary(skb) && tcp_v6_checksum_init(skb))
1613                 goto bad_packet;
1614
1615         th = tcp_hdr(skb);
1616         hdr = ipv6_hdr(skb);
1617         TCP_SKB_CB(skb)->seq = ntohl(th->seq);
1618         TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
1619                                     skb->len - th->doff*4);
1620         TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
1621         TCP_SKB_CB(skb)->when = 0;
1622         TCP_SKB_CB(skb)->ip_dsfield = ipv6_get_dsfield(hdr);
1623         TCP_SKB_CB(skb)->sacked = 0;
1624
1625         sk = __inet6_lookup_skb(&tcp_hashinfo, skb, th->source, th->dest);
1626         if (!sk)
1627                 goto no_tcp_socket;
1628
1629 process:
1630         if (sk->sk_state == TCP_TIME_WAIT)
1631                 goto do_time_wait;
1632
1633         if (hdr->hop_limit < inet6_sk(sk)->min_hopcount) {
1634                 NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP);
1635                 goto discard_and_relse;
1636         }
1637
1638         if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb))
1639                 goto discard_and_relse;
1640
1641         if (sk_filter(sk, skb))
1642                 goto discard_and_relse;
1643
1644         skb->dev = NULL;
1645
1646         bh_lock_sock_nested(sk);
1647         ret = 0;
1648         if (!sock_owned_by_user(sk)) {
1649 #ifdef CONFIG_NET_DMA
1650                 struct tcp_sock *tp = tcp_sk(sk);
1651                 if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list)
1652                         tp->ucopy.dma_chan = net_dma_find_channel();
1653                 if (tp->ucopy.dma_chan)
1654                         ret = tcp_v6_do_rcv(sk, skb);
1655                 else
1656 #endif
1657                 {
1658                         if (!tcp_prequeue(sk, skb))
1659                                 ret = tcp_v6_do_rcv(sk, skb);
1660                 }
1661         } else if (unlikely(sk_add_backlog(sk, skb))) {
1662                 bh_unlock_sock(sk);
1663                 NET_INC_STATS_BH(net, LINUX_MIB_TCPBACKLOGDROP);
1664                 goto discard_and_relse;
1665         }
1666         bh_unlock_sock(sk);
1667
1668         sock_put(sk);
1669         return ret ? -1 : 0;
1670
1671 no_tcp_socket:
1672         if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb))
1673                 goto discard_it;
1674
1675         if (skb->len < (th->doff<<2) || tcp_checksum_complete(skb)) {
1676 bad_packet:
1677                 TCP_INC_STATS_BH(net, TCP_MIB_INERRS);
1678         } else {
1679                 tcp_v6_send_reset(NULL, skb);
1680         }
1681
1682 discard_it:
1683
1684         /*
1685          *      Discard frame
1686          */
1687
1688         kfree_skb(skb);
1689         return 0;
1690
1691 discard_and_relse:
1692         sock_put(sk);
1693         goto discard_it;
1694
1695 do_time_wait:
1696         if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
1697                 inet_twsk_put(inet_twsk(sk));
1698                 goto discard_it;
1699         }
1700
1701         if (skb->len < (th->doff<<2) || tcp_checksum_complete(skb)) {
1702                 TCP_INC_STATS_BH(net, TCP_MIB_INERRS);
1703                 inet_twsk_put(inet_twsk(sk));
1704                 goto discard_it;
1705         }
1706
1707         switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) {
1708         case TCP_TW_SYN:
1709         {
1710                 struct sock *sk2;
1711
1712                 sk2 = inet6_lookup_listener(dev_net(skb->dev), &tcp_hashinfo,
1713                                             &ipv6_hdr(skb)->daddr,
1714                                             ntohs(th->dest), inet6_iif(skb));
1715                 if (sk2 != NULL) {
1716                         struct inet_timewait_sock *tw = inet_twsk(sk);
1717                         inet_twsk_deschedule(tw, &tcp_death_row);
1718                         inet_twsk_put(tw);
1719                         sk = sk2;
1720                         goto process;
1721                 }
1722                 /* Fall through to ACK */
1723         }
1724         case TCP_TW_ACK:
1725                 tcp_v6_timewait_ack(sk, skb);
1726                 break;
1727         case TCP_TW_RST:
1728                 goto no_tcp_socket;
1729         case TCP_TW_SUCCESS:;
1730         }
1731         goto discard_it;
1732 }
1733
1734 static struct inet_peer *tcp_v6_get_peer(struct sock *sk, bool *release_it)
1735 {
1736         struct rt6_info *rt = (struct rt6_info *) __sk_dst_get(sk);
1737         struct ipv6_pinfo *np = inet6_sk(sk);
1738         struct inet_peer *peer;
1739
1740         if (!rt ||
1741             !ipv6_addr_equal(&np->daddr, &rt->rt6i_dst.addr)) {
1742                 peer = inet_getpeer_v6(&np->daddr, 1);
1743                 *release_it = true;
1744         } else {
1745                 if (!rt->rt6i_peer)
1746                         rt6_bind_peer(rt, 1);
1747                 peer = rt->rt6i_peer;
1748                 *release_it = false;
1749         }
1750
1751         return peer;
1752 }
1753
1754 static void *tcp_v6_tw_get_peer(struct sock *sk)
1755 {
1756         const struct inet6_timewait_sock *tw6 = inet6_twsk(sk);
1757         const struct inet_timewait_sock *tw = inet_twsk(sk);
1758
1759         if (tw->tw_family == AF_INET)
1760                 return tcp_v4_tw_get_peer(sk);
1761
1762         return inet_getpeer_v6(&tw6->tw_v6_daddr, 1);
1763 }
1764
1765 static struct timewait_sock_ops tcp6_timewait_sock_ops = {
1766         .twsk_obj_size  = sizeof(struct tcp6_timewait_sock),
1767         .twsk_unique    = tcp_twsk_unique,
1768         .twsk_destructor= tcp_twsk_destructor,
1769         .twsk_getpeer   = tcp_v6_tw_get_peer,
1770 };
1771
1772 static const struct inet_connection_sock_af_ops ipv6_specific = {
1773         .queue_xmit        = inet6_csk_xmit,
1774         .send_check        = tcp_v6_send_check,
1775         .rebuild_header    = inet6_sk_rebuild_header,
1776         .conn_request      = tcp_v6_conn_request,
1777         .syn_recv_sock     = tcp_v6_syn_recv_sock,
1778         .get_peer          = tcp_v6_get_peer,
1779         .net_header_len    = sizeof(struct ipv6hdr),
1780         .setsockopt        = ipv6_setsockopt,
1781         .getsockopt        = ipv6_getsockopt,
1782         .addr2sockaddr     = inet6_csk_addr2sockaddr,
1783         .sockaddr_len      = sizeof(struct sockaddr_in6),
1784         .bind_conflict     = inet6_csk_bind_conflict,
1785 #ifdef CONFIG_COMPAT
1786         .compat_setsockopt = compat_ipv6_setsockopt,
1787         .compat_getsockopt = compat_ipv6_getsockopt,
1788 #endif
1789 };
1790
1791 #ifdef CONFIG_TCP_MD5SIG
1792 static const struct tcp_sock_af_ops tcp_sock_ipv6_specific = {
1793         .md5_lookup     =       tcp_v6_md5_lookup,
1794         .calc_md5_hash  =       tcp_v6_md5_hash_skb,
1795         .md5_parse      =       tcp_v6_parse_md5_keys,
1796 };
1797 #endif
1798
1799 /*
1800  *      TCP over IPv4 via INET6 API
1801  */
1802
1803 static const struct inet_connection_sock_af_ops ipv6_mapped = {
1804         .queue_xmit        = ip_queue_xmit,
1805         .send_check        = tcp_v4_send_check,
1806         .rebuild_header    = inet_sk_rebuild_header,
1807         .conn_request      = tcp_v6_conn_request,
1808         .syn_recv_sock     = tcp_v6_syn_recv_sock,
1809         .get_peer          = tcp_v4_get_peer,
1810         .net_header_len    = sizeof(struct iphdr),
1811         .setsockopt        = ipv6_setsockopt,
1812         .getsockopt        = ipv6_getsockopt,
1813         .addr2sockaddr     = inet6_csk_addr2sockaddr,
1814         .sockaddr_len      = sizeof(struct sockaddr_in6),
1815         .bind_conflict     = inet6_csk_bind_conflict,
1816 #ifdef CONFIG_COMPAT
1817         .compat_setsockopt = compat_ipv6_setsockopt,
1818         .compat_getsockopt = compat_ipv6_getsockopt,
1819 #endif
1820 };
1821
1822 #ifdef CONFIG_TCP_MD5SIG
1823 static const struct tcp_sock_af_ops tcp_sock_ipv6_mapped_specific = {
1824         .md5_lookup     =       tcp_v4_md5_lookup,
1825         .calc_md5_hash  =       tcp_v4_md5_hash_skb,
1826         .md5_parse      =       tcp_v6_parse_md5_keys,
1827 };
1828 #endif
1829
1830 /* NOTE: A lot of things set to zero explicitly by call to
1831  *       sk_alloc() so need not be done here.
1832  */
1833 static int tcp_v6_init_sock(struct sock *sk)
1834 {
1835         struct inet_connection_sock *icsk = inet_csk(sk);
1836         struct tcp_sock *tp = tcp_sk(sk);
1837
1838         skb_queue_head_init(&tp->out_of_order_queue);
1839         tcp_init_xmit_timers(sk);
1840         tcp_prequeue_init(tp);
1841
1842         icsk->icsk_rto = TCP_TIMEOUT_INIT;
1843         tp->mdev = TCP_TIMEOUT_INIT;
1844
1845         /* So many TCP implementations out there (incorrectly) count the
1846          * initial SYN frame in their delayed-ACK and congestion control
1847          * algorithms that we must have the following bandaid to talk
1848          * efficiently to them.  -DaveM
1849          */
1850         tp->snd_cwnd = 2;
1851
1852         /* See draft-stevens-tcpca-spec-01 for discussion of the
1853          * initialization of these values.
1854          */
1855         tp->snd_ssthresh = TCP_INFINITE_SSTHRESH;
1856         tp->snd_cwnd_clamp = ~0;
1857         tp->mss_cache = TCP_MSS_DEFAULT;
1858
1859         tp->reordering = sysctl_tcp_reordering;
1860
1861         sk->sk_state = TCP_CLOSE;
1862
1863         icsk->icsk_af_ops = &ipv6_specific;
1864         icsk->icsk_ca_ops = &tcp_init_congestion_ops;
1865         icsk->icsk_sync_mss = tcp_sync_mss;
1866         sk->sk_write_space = sk_stream_write_space;
1867         sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
1868
1869 #ifdef CONFIG_TCP_MD5SIG
1870         tp->af_specific = &tcp_sock_ipv6_specific;
1871 #endif
1872
1873         /* TCP Cookie Transactions */
1874         if (sysctl_tcp_cookie_size > 0) {
1875                 /* Default, cookies without s_data_payload. */
1876                 tp->cookie_values =
1877                         kzalloc(sizeof(*tp->cookie_values),
1878                                 sk->sk_allocation);
1879                 if (tp->cookie_values != NULL)
1880                         kref_init(&tp->cookie_values->kref);
1881         }
1882         /* Presumed zeroed, in order of appearance:
1883          *      cookie_in_always, cookie_out_never,
1884          *      s_data_constant, s_data_in, s_data_out
1885          */
1886         sk->sk_sndbuf = sysctl_tcp_wmem[1];
1887         sk->sk_rcvbuf = sysctl_tcp_rmem[1];
1888
1889         local_bh_disable();
1890         sock_update_memcg(sk);
1891         sk_sockets_allocated_inc(sk);
1892         local_bh_enable();
1893
1894         return 0;
1895 }
1896
1897 static void tcp_v6_destroy_sock(struct sock *sk)
1898 {
1899         tcp_v4_destroy_sock(sk);
1900         inet6_destroy_sock(sk);
1901 }
1902
1903 #ifdef CONFIG_PROC_FS
1904 /* Proc filesystem TCPv6 sock list dumping. */
1905 static void get_openreq6(struct seq_file *seq,
1906                          const struct sock *sk, struct request_sock *req, int i, int uid)
1907 {
1908         int ttd = req->expires - jiffies;
1909         const struct in6_addr *src = &inet6_rsk(req)->loc_addr;
1910         const struct in6_addr *dest = &inet6_rsk(req)->rmt_addr;
1911
1912         if (ttd < 0)
1913                 ttd = 0;
1914
1915         seq_printf(seq,
1916                    "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
1917                    "%02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK\n",
1918                    i,
1919                    src->s6_addr32[0], src->s6_addr32[1],
1920                    src->s6_addr32[2], src->s6_addr32[3],
1921                    ntohs(inet_rsk(req)->loc_port),
1922                    dest->s6_addr32[0], dest->s6_addr32[1],
1923                    dest->s6_addr32[2], dest->s6_addr32[3],
1924                    ntohs(inet_rsk(req)->rmt_port),
1925                    TCP_SYN_RECV,
1926                    0,0, /* could print option size, but that is af dependent. */
1927                    1,   /* timers active (only the expire timer) */
1928                    jiffies_to_clock_t(ttd),
1929                    req->retrans,
1930                    uid,
1931                    0,  /* non standard timer */
1932                    0, /* open_requests have no inode */
1933                    0, req);
1934 }
1935
1936 static void get_tcp6_sock(struct seq_file *seq, struct sock *sp, int i)
1937 {
1938         const struct in6_addr *dest, *src;
1939         __u16 destp, srcp;
1940         int timer_active;
1941         unsigned long timer_expires;
1942         const struct inet_sock *inet = inet_sk(sp);
1943         const struct tcp_sock *tp = tcp_sk(sp);
1944         const struct inet_connection_sock *icsk = inet_csk(sp);
1945         const struct ipv6_pinfo *np = inet6_sk(sp);
1946
1947         dest  = &np->daddr;
1948         src   = &np->rcv_saddr;
1949         destp = ntohs(inet->inet_dport);
1950         srcp  = ntohs(inet->inet_sport);
1951
1952         if (icsk->icsk_pending == ICSK_TIME_RETRANS) {
1953                 timer_active    = 1;
1954                 timer_expires   = icsk->icsk_timeout;
1955         } else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
1956                 timer_active    = 4;
1957                 timer_expires   = icsk->icsk_timeout;
1958         } else if (timer_pending(&sp->sk_timer)) {
1959                 timer_active    = 2;
1960                 timer_expires   = sp->sk_timer.expires;
1961         } else {
1962                 timer_active    = 0;
1963                 timer_expires = jiffies;
1964         }
1965
1966         seq_printf(seq,
1967                    "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
1968                    "%02X %08X:%08X %02X:%08lX %08X %5d %8d %lu %d %pK %lu %lu %u %u %d\n",
1969                    i,
1970                    src->s6_addr32[0], src->s6_addr32[1],
1971                    src->s6_addr32[2], src->s6_addr32[3], srcp,
1972                    dest->s6_addr32[0], dest->s6_addr32[1],
1973                    dest->s6_addr32[2], dest->s6_addr32[3], destp,
1974                    sp->sk_state,
1975                    tp->write_seq-tp->snd_una,
1976                    (sp->sk_state == TCP_LISTEN) ? sp->sk_ack_backlog : (tp->rcv_nxt - tp->copied_seq),
1977                    timer_active,
1978                    jiffies_to_clock_t(timer_expires - jiffies),
1979                    icsk->icsk_retransmits,
1980                    sock_i_uid(sp),
1981                    icsk->icsk_probes_out,
1982                    sock_i_ino(sp),
1983                    atomic_read(&sp->sk_refcnt), sp,
1984                    jiffies_to_clock_t(icsk->icsk_rto),
1985                    jiffies_to_clock_t(icsk->icsk_ack.ato),
1986                    (icsk->icsk_ack.quick << 1 ) | icsk->icsk_ack.pingpong,
1987                    tp->snd_cwnd,
1988                    tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh
1989                    );
1990 }
1991
1992 static void get_timewait6_sock(struct seq_file *seq,
1993                                struct inet_timewait_sock *tw, int i)
1994 {
1995         const struct in6_addr *dest, *src;
1996         __u16 destp, srcp;
1997         const struct inet6_timewait_sock *tw6 = inet6_twsk((struct sock *)tw);
1998         int ttd = tw->tw_ttd - jiffies;
1999
2000         if (ttd < 0)
2001                 ttd = 0;
2002
2003         dest = &tw6->tw_v6_daddr;
2004         src  = &tw6->tw_v6_rcv_saddr;
2005         destp = ntohs(tw->tw_dport);
2006         srcp  = ntohs(tw->tw_sport);
2007
2008         seq_printf(seq,
2009                    "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
2010                    "%02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK\n",
2011                    i,
2012                    src->s6_addr32[0], src->s6_addr32[1],
2013                    src->s6_addr32[2], src->s6_addr32[3], srcp,
2014                    dest->s6_addr32[0], dest->s6_addr32[1],
2015                    dest->s6_addr32[2], dest->s6_addr32[3], destp,
2016                    tw->tw_substate, 0, 0,
2017                    3, jiffies_to_clock_t(ttd), 0, 0, 0, 0,
2018                    atomic_read(&tw->tw_refcnt), tw);
2019 }
2020
2021 static int tcp6_seq_show(struct seq_file *seq, void *v)
2022 {
2023         struct tcp_iter_state *st;
2024
2025         if (v == SEQ_START_TOKEN) {
2026                 seq_puts(seq,
2027                          "  sl  "
2028                          "local_address                         "
2029                          "remote_address                        "
2030                          "st tx_queue rx_queue tr tm->when retrnsmt"
2031                          "   uid  timeout inode\n");
2032                 goto out;
2033         }
2034         st = seq->private;
2035
2036         switch (st->state) {
2037         case TCP_SEQ_STATE_LISTENING:
2038         case TCP_SEQ_STATE_ESTABLISHED:
2039                 get_tcp6_sock(seq, v, st->num);
2040                 break;
2041         case TCP_SEQ_STATE_OPENREQ:
2042                 get_openreq6(seq, st->syn_wait_sk, v, st->num, st->uid);
2043                 break;
2044         case TCP_SEQ_STATE_TIME_WAIT:
2045                 get_timewait6_sock(seq, v, st->num);
2046                 break;
2047         }
2048 out:
2049         return 0;
2050 }
2051
2052 static const struct file_operations tcp6_afinfo_seq_fops = {
2053         .owner   = THIS_MODULE,
2054         .open    = tcp_seq_open,
2055         .read    = seq_read,
2056         .llseek  = seq_lseek,
2057         .release = seq_release_net
2058 };
2059
2060 static struct tcp_seq_afinfo tcp6_seq_afinfo = {
2061         .name           = "tcp6",
2062         .family         = AF_INET6,
2063         .seq_fops       = &tcp6_afinfo_seq_fops,
2064         .seq_ops        = {
2065                 .show           = tcp6_seq_show,
2066         },
2067 };
2068
2069 int __net_init tcp6_proc_init(struct net *net)
2070 {
2071         return tcp_proc_register(net, &tcp6_seq_afinfo);
2072 }
2073
2074 void tcp6_proc_exit(struct net *net)
2075 {
2076         tcp_proc_unregister(net, &tcp6_seq_afinfo);
2077 }
2078 #endif
2079
2080 struct proto tcpv6_prot = {
2081         .name                   = "TCPv6",
2082         .owner                  = THIS_MODULE,
2083         .close                  = tcp_close,
2084         .connect                = tcp_v6_connect,
2085         .disconnect             = tcp_disconnect,
2086         .accept                 = inet_csk_accept,
2087         .ioctl                  = tcp_ioctl,
2088         .init                   = tcp_v6_init_sock,
2089         .destroy                = tcp_v6_destroy_sock,
2090         .shutdown               = tcp_shutdown,
2091         .setsockopt             = tcp_setsockopt,
2092         .getsockopt             = tcp_getsockopt,
2093         .recvmsg                = tcp_recvmsg,
2094         .sendmsg                = tcp_sendmsg,
2095         .sendpage               = tcp_sendpage,
2096         .backlog_rcv            = tcp_v6_do_rcv,
2097         .hash                   = tcp_v6_hash,
2098         .unhash                 = inet_unhash,
2099         .get_port               = inet_csk_get_port,
2100         .enter_memory_pressure  = tcp_enter_memory_pressure,
2101         .sockets_allocated      = &tcp_sockets_allocated,
2102         .memory_allocated       = &tcp_memory_allocated,
2103         .memory_pressure        = &tcp_memory_pressure,
2104         .orphan_count           = &tcp_orphan_count,
2105         .sysctl_wmem            = sysctl_tcp_wmem,
2106         .sysctl_rmem            = sysctl_tcp_rmem,
2107         .max_header             = MAX_TCP_HEADER,
2108         .obj_size               = sizeof(struct tcp6_sock),
2109         .slab_flags             = SLAB_DESTROY_BY_RCU,
2110         .twsk_prot              = &tcp6_timewait_sock_ops,
2111         .rsk_prot               = &tcp6_request_sock_ops,
2112         .h.hashinfo             = &tcp_hashinfo,
2113         .no_autobind            = true,
2114 #ifdef CONFIG_COMPAT
2115         .compat_setsockopt      = compat_tcp_setsockopt,
2116         .compat_getsockopt      = compat_tcp_getsockopt,
2117 #endif
2118 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM
2119         .proto_cgroup           = tcp_proto_cgroup,
2120 #endif
2121 };
2122
2123 static const struct inet6_protocol tcpv6_protocol = {
2124         .handler        =       tcp_v6_rcv,
2125         .err_handler    =       tcp_v6_err,
2126         .gso_send_check =       tcp_v6_gso_send_check,
2127         .gso_segment    =       tcp_tso_segment,
2128         .gro_receive    =       tcp6_gro_receive,
2129         .gro_complete   =       tcp6_gro_complete,
2130         .flags          =       INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
2131 };
2132
2133 static struct inet_protosw tcpv6_protosw = {
2134         .type           =       SOCK_STREAM,
2135         .protocol       =       IPPROTO_TCP,
2136         .prot           =       &tcpv6_prot,
2137         .ops            =       &inet6_stream_ops,
2138         .no_check       =       0,
2139         .flags          =       INET_PROTOSW_PERMANENT |
2140                                 INET_PROTOSW_ICSK,
2141 };
2142
2143 static int __net_init tcpv6_net_init(struct net *net)
2144 {
2145         return inet_ctl_sock_create(&net->ipv6.tcp_sk, PF_INET6,
2146                                     SOCK_RAW, IPPROTO_TCP, net);
2147 }
2148
2149 static void __net_exit tcpv6_net_exit(struct net *net)
2150 {
2151         inet_ctl_sock_destroy(net->ipv6.tcp_sk);
2152 }
2153
2154 static void __net_exit tcpv6_net_exit_batch(struct list_head *net_exit_list)
2155 {
2156         inet_twsk_purge(&tcp_hashinfo, &tcp_death_row, AF_INET6);
2157 }
2158
2159 static struct pernet_operations tcpv6_net_ops = {
2160         .init       = tcpv6_net_init,
2161         .exit       = tcpv6_net_exit,
2162         .exit_batch = tcpv6_net_exit_batch,
2163 };
2164
2165 int __init tcpv6_init(void)
2166 {
2167         int ret;
2168
2169         ret = inet6_add_protocol(&tcpv6_protocol, IPPROTO_TCP);
2170         if (ret)
2171                 goto out;
2172
2173         /* register inet6 protocol */
2174         ret = inet6_register_protosw(&tcpv6_protosw);
2175         if (ret)
2176                 goto out_tcpv6_protocol;
2177
2178         ret = register_pernet_subsys(&tcpv6_net_ops);
2179         if (ret)
2180                 goto out_tcpv6_protosw;
2181 out:
2182         return ret;
2183
2184 out_tcpv6_protocol:
2185         inet6_del_protocol(&tcpv6_protocol, IPPROTO_TCP);
2186 out_tcpv6_protosw:
2187         inet6_unregister_protosw(&tcpv6_protosw);
2188         goto out;
2189 }
2190
2191 void tcpv6_exit(void)
2192 {
2193         unregister_pernet_subsys(&tcpv6_net_ops);
2194         inet6_unregister_protosw(&tcpv6_protosw);
2195         inet6_del_protocol(&tcpv6_protocol, IPPROTO_TCP);
2196 }