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
  66 #include <asm/uaccess.h>
  67
  68 #include <linux/proc_fs.h>
  69 #include <linux/seq_file.h>
  70
  71 #include <linux/crypto.h>
  72 #include <linux/scatterlist.h>
  73
  74 static void     tcp_v6_send_reset(struct sock *sk, struct sk_buff *skb);
  75 static void     tcp_v6_reqsk_send_ack(struct sock *sk, struct sk_buff *skb,
  76                                       struct request_sock *req);
  77
  78 static int      tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb);
  79 static void     __tcp_v6_send_check(struct sk_buff *skb,
  80                                     const struct in6_addr *saddr,
  81                                     const struct in6_addr *daddr);
  82
  83 static const struct inet_connection_sock_af_ops ipv6_mapped;
  84 static const struct inet_connection_sock_af_ops ipv6_specific;
  85 #ifdef CONFIG_TCP_MD5SIG
  86 static const struct tcp_sock_af_ops tcp_sock_ipv6_specific;
  87 static const struct tcp_sock_af_ops tcp_sock_ipv6_mapped_specific;
  88 #else
  89 static struct tcp_md5sig_key *tcp_v6_md5_do_lookup(struct sock *sk,
  90                                                    const struct in6_addr *addr)
  91 {
  92         return NULL;
  93 }
  94 #endif
  95
  96 static void tcp_v6_hash(struct sock *sk)
  97 {
  98         if (sk->sk_state != TCP_CLOSE) {
  99                 if (inet_csk(sk)->icsk_af_ops == &ipv6_mapped) {
 100                         tcp_prot.hash(sk);
 101                         return;
 102                 }
 103                 local_bh_disable();
 104                 __inet6_hash(sk, NULL);
 105                 local_bh_enable();
 106         }
 107 }
 108
 109 static __inline__ __sum16 tcp_v6_check(int len,
 110                                    const struct in6_addr *saddr,
 111                                    const struct in6_addr *daddr,
 112                                    __wsum base)
 113 {
 114         return csum_ipv6_magic(saddr, daddr, len, IPPROTO_TCP, base);
 115 }
 116
 117 static __u32 tcp_v6_init_sequence(const struct sk_buff *skb)
 118 {
 119         return secure_tcpv6_sequence_number(ipv6_hdr(skb)->daddr.s6_addr32,
 120                                             ipv6_hdr(skb)->saddr.s6_addr32,
 121                                             tcp_hdr(skb)->dest,
 122                                             tcp_hdr(skb)->source);
 123 }
 124
 125 static int tcp_v6_connect(struct sock *sk, struct sockaddr *uaddr,
 126                           int addr_len)
 127 {
 128         struct sockaddr_in6 *usin = (struct sockaddr_in6 *) uaddr;
 129         struct inet_sock *inet = inet_sk(sk);
 130         struct inet_connection_sock *icsk = inet_csk(sk);
 131         struct ipv6_pinfo *np = inet6_sk(sk);
 132         struct tcp_sock *tp = tcp_sk(sk);
 133         struct in6_addr *saddr = NULL, *final_p, final;
 134         struct rt6_info *rt;
 135         struct flowi6 fl6;
 136         struct dst_entry *dst;
 137         int addr_type;
 138         int err;
 139
 140         if (addr_len < SIN6_LEN_RFC2133)
 141                 return -EINVAL;
 142
 143         if (usin->sin6_family != AF_INET6)
 144                 return -EAFNOSUPPORT;
 145
 146         memset(&fl6, 0, sizeof(fl6));
 147
 148         if (np->sndflow) {
 149                 fl6.flowlabel = usin->sin6_flowinfo&IPV6_FLOWINFO_MASK;
 150                 IP6_ECN_flow_init(fl6.flowlabel);
 151                 if (fl6.flowlabel&IPV6_FLOWLABEL_MASK) {
 152                         struct ip6_flowlabel *flowlabel;
 153                         flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
 154                         if (flowlabel == NULL)
 155                                 return -EINVAL;
 156                         ipv6_addr_copy(&usin->sin6_addr, &flowlabel->dst);
 157                         fl6_sock_release(flowlabel);
 158                 }
 159         }
 160
 161         /*
 162          *      connect() to INADDR_ANY means loopback (BSD'ism).
 163          */
 164
 165         if(ipv6_addr_any(&usin->sin6_addr))
 166                 usin->sin6_addr.s6_addr[15] = 0x1;
 167
 168         addr_type = ipv6_addr_type(&usin->sin6_addr);
 169
 170         if(addr_type & IPV6_ADDR_MULTICAST)
 171                 return -ENETUNREACH;
 172
 173         if (addr_type&IPV6_ADDR_LINKLOCAL) {
 174                 if (addr_len >= sizeof(struct sockaddr_in6) &&
 175                     usin->sin6_scope_id) {
 176                         /* If interface is set while binding, indices
 177                          * must coincide.
 178                          */
 179                         if (sk->sk_bound_dev_if &&
 180                             sk->sk_bound_dev_if != usin->sin6_scope_id)
 181                                 return -EINVAL;
 182
 183                         sk->sk_bound_dev_if = usin->sin6_scope_id;
 184                 }
 185
 186                 /* Connect to link-local address requires an interface */
 187                 if (!sk->sk_bound_dev_if)
 188                         return -EINVAL;
 189         }
 190
 191         if (tp->rx_opt.ts_recent_stamp &&
 192             !ipv6_addr_equal(&np->daddr, &usin->sin6_addr)) {
 193                 tp->rx_opt.ts_recent = 0;
 194                 tp->rx_opt.ts_recent_stamp = 0;
 195                 tp->write_seq = 0;
 196         }
 197
 198         ipv6_addr_copy(&np->daddr, &usin->sin6_addr);
 199         np->flow_label = fl6.flowlabel;
 200
 201         /*
 202          *      TCP over IPv4
 203          */
 204
 205         if (addr_type == IPV6_ADDR_MAPPED) {
 206                 u32 exthdrlen = icsk->icsk_ext_hdr_len;
 207                 struct sockaddr_in sin;
 208
 209                 SOCK_DEBUG(sk, "connect: ipv4 mapped\n");
 210
 211                 if (__ipv6_only_sock(sk))
 212                         return -ENETUNREACH;
 213
 214                 sin.sin_family = AF_INET;
 215                 sin.sin_port = usin->sin6_port;
 216                 sin.sin_addr.s_addr = usin->sin6_addr.s6_addr32[3];
 217
 218                 icsk->icsk_af_ops = &ipv6_mapped;
 219                 sk->sk_backlog_rcv = tcp_v4_do_rcv;
 220 #ifdef CONFIG_TCP_MD5SIG
 221                 tp->af_specific = &tcp_sock_ipv6_mapped_specific;
 222 #endif
 223
 224                 err = tcp_v4_connect(sk, (struct sockaddr *)&sin, sizeof(sin));
 225
 226                 if (err) {
 227                         icsk->icsk_ext_hdr_len = exthdrlen;
 228                         icsk->icsk_af_ops = &ipv6_specific;
 229                         sk->sk_backlog_rcv = tcp_v6_do_rcv;
 230 #ifdef CONFIG_TCP_MD5SIG
 231                         tp->af_specific = &tcp_sock_ipv6_specific;
 232 #endif
 233                         goto failure;
 234                 } else {
 235                         ipv6_addr_set_v4mapped(inet->inet_saddr, &np->saddr);
 236                         ipv6_addr_set_v4mapped(inet->inet_rcv_saddr,
 237                                                &np->rcv_saddr);
 238                 }
 239
 240                 return err;
 241         }
 242
 243         if (!ipv6_addr_any(&np->rcv_saddr))
 244                 saddr = &np->rcv_saddr;
 245
 246         fl6.flowi6_proto = IPPROTO_TCP;
 247         ipv6_addr_copy(&fl6.daddr, &np->daddr);
 248         ipv6_addr_copy(&fl6.saddr,
 249                        (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                 ipv6_addr_copy(&np->rcv_saddr, saddr);
 268         }
 269
 270         /* set the source address */
 271         ipv6_addr_copy(&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                         ipv6_addr_copy(&fl6.daddr, &np->daddr);
 402                         ipv6_addr_copy(&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         ipv6_addr_copy(&fl6.daddr, &treq->rmt_addr);
 493         ipv6_addr_copy(&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                 ipv6_addr_copy(&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         struct tcp_sock *tp = tcp_sk(sk);
 544         int i;
 545
 546         BUG_ON(tp == NULL);
 547
 548         if (!tp->md5sig_info || !tp->md5sig_info->entries6)
 549                 return NULL;
 550
 551         for (i = 0; i < tp->md5sig_info->entries6; i++) {
 552                 if (ipv6_addr_equal(&tp->md5sig_info->keys6[i].addr, addr))
 553                         return &tp->md5sig_info->keys6[i].base;
 554         }
 555         return NULL;
 556 }
 557
 558 static struct tcp_md5sig_key *tcp_v6_md5_lookup(struct sock *sk,
 559                                                 struct sock *addr_sk)
 560 {
 561         return tcp_v6_md5_do_lookup(sk, &inet6_sk(addr_sk)->daddr);
 562 }
 563
 564 static struct tcp_md5sig_key *tcp_v6_reqsk_md5_lookup(struct sock *sk,
 565                                                       struct request_sock *req)
 566 {
 567         return tcp_v6_md5_do_lookup(sk, &inet6_rsk(req)->rmt_addr);
 568 }
 569
 570 static int tcp_v6_md5_do_add(struct sock *sk, const struct in6_addr *peer,
 571                              char *newkey, u8 newkeylen)
 572 {
 573         /* Add key to the list */
 574         struct tcp_md5sig_key *key;
 575         struct tcp_sock *tp = tcp_sk(sk);
 576         struct tcp6_md5sig_key *keys;
 577
 578         key = tcp_v6_md5_do_lookup(sk, peer);
 579         if (key) {
 580                 /* modify existing entry - just update that one */
 581                 kfree(key->key);
 582                 key->key = newkey;
 583                 key->keylen = newkeylen;
 584         } else {
 585                 /* reallocate new list if current one is full. */
 586                 if (!tp->md5sig_info) {
 587                         tp->md5sig_info = kzalloc(sizeof(*tp->md5sig_info), GFP_ATOMIC);
 588                         if (!tp->md5sig_info) {
 589                                 kfree(newkey);
 590                                 return -ENOMEM;
 591                         }
 592                         sk_nocaps_add(sk, NETIF_F_GSO_MASK);
 593                 }
 594                 if (tp->md5sig_info->entries6 == 0 &&
 595                         tcp_alloc_md5sig_pool(sk) == NULL) {
 596                         kfree(newkey);
 597                         return -ENOMEM;
 598                 }
 599                 if (tp->md5sig_info->alloced6 == tp->md5sig_info->entries6) {
 600                         keys = kmalloc((sizeof (tp->md5sig_info->keys6[0]) *
 601                                        (tp->md5sig_info->entries6 + 1)), GFP_ATOMIC);
 602
 603                         if (!keys) {
 604                                 kfree(newkey);
 605                                 if (tp->md5sig_info->entries6 == 0)
 606                                         tcp_free_md5sig_pool();
 607                                 return -ENOMEM;
 608                         }
 609
 610                         if (tp->md5sig_info->entries6)
 611                                 memmove(keys, tp->md5sig_info->keys6,
 612                                         (sizeof (tp->md5sig_info->keys6[0]) *
 613                                          tp->md5sig_info->entries6));
 614
 615                         kfree(tp->md5sig_info->keys6);
 616                         tp->md5sig_info->keys6 = keys;
 617                         tp->md5sig_info->alloced6++;
 618                 }
 619
 620                 ipv6_addr_copy(&tp->md5sig_info->keys6[tp->md5sig_info->entries6].addr,
 621                                peer);
 622                 tp->md5sig_info->keys6[tp->md5sig_info->entries6].base.key = newkey;
 623                 tp->md5sig_info->keys6[tp->md5sig_info->entries6].base.keylen = newkeylen;
 624
 625                 tp->md5sig_info->entries6++;
 626         }
 627         return 0;
 628 }
 629
 630 static int tcp_v6_md5_add_func(struct sock *sk, struct sock *addr_sk,
 631                                u8 *newkey, __u8 newkeylen)
 632 {
 633         return tcp_v6_md5_do_add(sk, &inet6_sk(addr_sk)->daddr,
 634                                  newkey, newkeylen);
 635 }
 636
 637 static int tcp_v6_md5_do_del(struct sock *sk, const struct in6_addr *peer)
 638 {
 639         struct tcp_sock *tp = tcp_sk(sk);
 640         int i;
 641
 642         for (i = 0; i < tp->md5sig_info->entries6; i++) {
 643                 if (ipv6_addr_equal(&tp->md5sig_info->keys6[i].addr, peer)) {
 644                         /* Free the key */
 645                         kfree(tp->md5sig_info->keys6[i].base.key);
 646                         tp->md5sig_info->entries6--;
 647
 648                         if (tp->md5sig_info->entries6 == 0) {
 649                                 kfree(tp->md5sig_info->keys6);
 650                                 tp->md5sig_info->keys6 = NULL;
 651                                 tp->md5sig_info->alloced6 = 0;
 652                                 tcp_free_md5sig_pool();
 653                         } else {
 654                                 /* shrink the database */
 655                                 if (tp->md5sig_info->entries6 != i)
 656                                         memmove(&tp->md5sig_info->keys6[i],
 657                                                 &tp->md5sig_info->keys6[i+1],
 658                                                 (tp->md5sig_info->entries6 - i)
 659                                                 * sizeof (tp->md5sig_info->keys6[0]));
 660                         }
 661                         return 0;
 662                 }
 663         }
 664         return -ENOENT;
 665 }
 666
 667 static void tcp_v6_clear_md5_list (struct sock *sk)
 668 {
 669         struct tcp_sock *tp = tcp_sk(sk);
 670         int i;
 671
 672         if (tp->md5sig_info->entries6) {
 673                 for (i = 0; i < tp->md5sig_info->entries6; i++)
 674                         kfree(tp->md5sig_info->keys6[i].base.key);
 675                 tp->md5sig_info->entries6 = 0;
 676                 tcp_free_md5sig_pool();
 677         }
 678
 679         kfree(tp->md5sig_info->keys6);
 680         tp->md5sig_info->keys6 = NULL;
 681         tp->md5sig_info->alloced6 = 0;
 682
 683         if (tp->md5sig_info->entries4) {
 684                 for (i = 0; i < tp->md5sig_info->entries4; i++)
 685                         kfree(tp->md5sig_info->keys4[i].base.key);
 686                 tp->md5sig_info->entries4 = 0;
 687                 tcp_free_md5sig_pool();
 688         }
 689
 690         kfree(tp->md5sig_info->keys4);
 691         tp->md5sig_info->keys4 = NULL;
 692         tp->md5sig_info->alloced4 = 0;
 693 }
 694
 695 static int tcp_v6_parse_md5_keys (struct sock *sk, char __user *optval,
 696                                   int optlen)
 697 {
 698         struct tcp_md5sig cmd;
 699         struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)&cmd.tcpm_addr;
 700         u8 *newkey;
 701
 702         if (optlen < sizeof(cmd))
 703                 return -EINVAL;
 704
 705         if (copy_from_user(&cmd, optval, sizeof(cmd)))
 706                 return -EFAULT;
 707
 708         if (sin6->sin6_family != AF_INET6)
 709                 return -EINVAL;
 710
 711         if (!cmd.tcpm_keylen) {
 712                 if (!tcp_sk(sk)->md5sig_info)
 713                         return -ENOENT;
 714                 if (ipv6_addr_v4mapped(&sin6->sin6_addr))
 715                         return tcp_v4_md5_do_del(sk, sin6->sin6_addr.s6_addr32[3]);
 716                 return tcp_v6_md5_do_del(sk, &sin6->sin6_addr);
 717         }
 718
 719         if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN)
 720                 return -EINVAL;
 721
 722         if (!tcp_sk(sk)->md5sig_info) {
 723                 struct tcp_sock *tp = tcp_sk(sk);
 724                 struct tcp_md5sig_info *p;
 725
 726                 p = kzalloc(sizeof(struct tcp_md5sig_info), GFP_KERNEL);
 727                 if (!p)
 728                         return -ENOMEM;
 729
 730                 tp->md5sig_info = p;
 731                 sk_nocaps_add(sk, NETIF_F_GSO_MASK);
 732         }
 733
 734         newkey = kmemdup(cmd.tcpm_key, cmd.tcpm_keylen, GFP_KERNEL);
 735         if (!newkey)
 736                 return -ENOMEM;
 737         if (ipv6_addr_v4mapped(&sin6->sin6_addr)) {
 738                 return tcp_v4_md5_do_add(sk, sin6->sin6_addr.s6_addr32[3],
 739                                          newkey, cmd.tcpm_keylen);
 740         }
 741         return tcp_v6_md5_do_add(sk, &sin6->sin6_addr, newkey, cmd.tcpm_keylen);
 742 }
 743
 744 static int tcp_v6_md5_hash_pseudoheader(struct tcp_md5sig_pool *hp,
 745                                         const struct in6_addr *daddr,
 746                                         const struct in6_addr *saddr, int nbytes)
 747 {
 748         struct tcp6_pseudohdr *bp;
 749         struct scatterlist sg;
 750
 751         bp = &hp->md5_blk.ip6;
 752         /* 1. TCP pseudo-header (RFC2460) */
 753         ipv6_addr_copy(&bp->saddr, saddr);
 754         ipv6_addr_copy(&bp->daddr, daddr);
 755         bp->protocol = cpu_to_be32(IPPROTO_TCP);
 756         bp->len = cpu_to_be32(nbytes);
 757
 758         sg_init_one(&sg, bp, sizeof(*bp));
 759         return crypto_hash_update(&hp->md5_desc, &sg, sizeof(*bp));
 760 }
 761
 762 static int tcp_v6_md5_hash_hdr(char *md5_hash, struct tcp_md5sig_key *key,
 763                                const struct in6_addr *daddr, struct in6_addr *saddr,
 764                                const struct tcphdr *th)
 765 {
 766         struct tcp_md5sig_pool *hp;
 767         struct hash_desc *desc;
 768
 769         hp = tcp_get_md5sig_pool();
 770         if (!hp)
 771                 goto clear_hash_noput;
 772         desc = &hp->md5_desc;
 773
 774         if (crypto_hash_init(desc))
 775                 goto clear_hash;
 776         if (tcp_v6_md5_hash_pseudoheader(hp, daddr, saddr, th->doff << 2))
 777                 goto clear_hash;
 778         if (tcp_md5_hash_header(hp, th))
 779                 goto clear_hash;
 780         if (tcp_md5_hash_key(hp, key))
 781                 goto clear_hash;
 782         if (crypto_hash_final(desc, md5_hash))
 783                 goto clear_hash;
 784
 785         tcp_put_md5sig_pool();
 786         return 0;
 787
 788 clear_hash:
 789         tcp_put_md5sig_pool();
 790 clear_hash_noput:
 791         memset(md5_hash, 0, 16);
 792         return 1;
 793 }
 794
 795 static int tcp_v6_md5_hash_skb(char *md5_hash, struct tcp_md5sig_key *key,
 796                                const struct sock *sk,
 797                                const struct request_sock *req,
 798                                const struct sk_buff *skb)
 799 {
 800         const struct in6_addr *saddr, *daddr;
 801         struct tcp_md5sig_pool *hp;
 802         struct hash_desc *desc;
 803         const struct tcphdr *th = tcp_hdr(skb);
 804
 805         if (sk) {
 806                 saddr = &inet6_sk(sk)->saddr;
 807                 daddr = &inet6_sk(sk)->daddr;
 808         } else if (req) {
 809                 saddr = &inet6_rsk(req)->loc_addr;
 810                 daddr = &inet6_rsk(req)->rmt_addr;
 811         } else {
 812                 const struct ipv6hdr *ip6h = ipv6_hdr(skb);
 813                 saddr = &ip6h->saddr;
 814                 daddr = &ip6h->daddr;
 815         }
 816
 817         hp = tcp_get_md5sig_pool();
 818         if (!hp)
 819                 goto clear_hash_noput;
 820         desc = &hp->md5_desc;
 821
 822         if (crypto_hash_init(desc))
 823                 goto clear_hash;
 824
 825         if (tcp_v6_md5_hash_pseudoheader(hp, daddr, saddr, skb->len))
 826                 goto clear_hash;
 827         if (tcp_md5_hash_header(hp, th))
 828                 goto clear_hash;
 829         if (tcp_md5_hash_skb_data(hp, skb, th->doff << 2))
 830                 goto clear_hash;
 831         if (tcp_md5_hash_key(hp, key))
 832                 goto clear_hash;
 833         if (crypto_hash_final(desc, md5_hash))
 834                 goto clear_hash;
 835
 836         tcp_put_md5sig_pool();
 837         return 0;
 838
 839 clear_hash:
 840         tcp_put_md5sig_pool();
 841 clear_hash_noput:
 842         memset(md5_hash, 0, 16);
 843         return 1;
 844 }
 845
 846 static int tcp_v6_inbound_md5_hash(struct sock *sk, const struct sk_buff *skb)
 847 {
 848         const __u8 *hash_location = NULL;
 849         struct tcp_md5sig_key *hash_expected;
 850         const struct ipv6hdr *ip6h = ipv6_hdr(skb);
 851         const struct tcphdr *th = tcp_hdr(skb);
 852         int genhash;
 853         u8 newhash[16];
 854
 855         hash_expected = tcp_v6_md5_do_lookup(sk, &ip6h->saddr);
 856         hash_location = tcp_parse_md5sig_option(th);
 857
 858         /* We've parsed the options - do we have a hash? */
 859         if (!hash_expected && !hash_location)
 860                 return 0;
 861
 862         if (hash_expected && !hash_location) {
 863                 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5NOTFOUND);
 864                 return 1;
 865         }
 866
 867         if (!hash_expected && hash_location) {
 868                 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5UNEXPECTED);
 869                 return 1;
 870         }
 871
 872         /* check the signature */
 873         genhash = tcp_v6_md5_hash_skb(newhash,
 874                                       hash_expected,
 875                                       NULL, NULL, skb);
 876
 877         if (genhash || memcmp(hash_location, newhash, 16) != 0) {
 878                 if (net_ratelimit()) {
 879                         printk(KERN_INFO "MD5 Hash %s for [%pI6c]:%u->[%pI6c]:%u\n",
 880                                genhash ? "failed" : "mismatch",
 881                                &ip6h->saddr, ntohs(th->source),
 882                                &ip6h->daddr, ntohs(th->dest));
 883                 }
 884                 return 1;
 885         }
 886         return 0;
 887 }
 888 #endif
 889
 890 struct request_sock_ops tcp6_request_sock_ops __read_mostly = {
 891         .family         =       AF_INET6,
 892         .obj_size       =       sizeof(struct tcp6_request_sock),
 893         .rtx_syn_ack    =       tcp_v6_rtx_synack,
 894         .send_ack       =       tcp_v6_reqsk_send_ack,
 895         .destructor     =       tcp_v6_reqsk_destructor,
 896         .send_reset     =       tcp_v6_send_reset,
 897         .syn_ack_timeout =      tcp_syn_ack_timeout,
 898 };
 899
 900 #ifdef CONFIG_TCP_MD5SIG
 901 static const struct tcp_request_sock_ops tcp_request_sock_ipv6_ops = {
 902         .md5_lookup     =       tcp_v6_reqsk_md5_lookup,
 903         .calc_md5_hash  =       tcp_v6_md5_hash_skb,
 904 };
 905 #endif
 906
 907 static void __tcp_v6_send_check(struct sk_buff *skb,
 908                                 const struct in6_addr *saddr, const struct in6_addr *daddr)
 909 {
 910         struct tcphdr *th = tcp_hdr(skb);
 911
 912         if (skb->ip_summed == CHECKSUM_PARTIAL) {
 913                 th->check = ~tcp_v6_check(skb->len, saddr, daddr, 0);
 914                 skb->csum_start = skb_transport_header(skb) - skb->head;
 915                 skb->csum_offset = offsetof(struct tcphdr, check);
 916         } else {
 917                 th->check = tcp_v6_check(skb->len, saddr, daddr,
 918                                          csum_partial(th, th->doff << 2,
 919                                                       skb->csum));
 920         }
 921 }
 922
 923 static void tcp_v6_send_check(struct sock *sk, struct sk_buff *skb)
 924 {
 925         struct ipv6_pinfo *np = inet6_sk(sk);
 926
 927         __tcp_v6_send_check(skb, &np->saddr, &np->daddr);
 928 }
 929
 930 static int tcp_v6_gso_send_check(struct sk_buff *skb)
 931 {
 932         const struct ipv6hdr *ipv6h;
 933         struct tcphdr *th;
 934
 935         if (!pskb_may_pull(skb, sizeof(*th)))
 936                 return -EINVAL;
 937
 938         ipv6h = ipv6_hdr(skb);
 939         th = tcp_hdr(skb);
 940
 941         th->check = 0;
 942         skb->ip_summed = CHECKSUM_PARTIAL;
 943         __tcp_v6_send_check(skb, &ipv6h->saddr, &ipv6h->daddr);
 944         return 0;
 945 }
 946
 947 static struct sk_buff **tcp6_gro_receive(struct sk_buff **head,
 948                                          struct sk_buff *skb)
 949 {
 950         const struct ipv6hdr *iph = skb_gro_network_header(skb);
 951
 952         switch (skb->ip_summed) {
 953         case CHECKSUM_COMPLETE:
 954                 if (!tcp_v6_check(skb_gro_len(skb), &iph->saddr, &iph->daddr,
 955                                   skb->csum)) {
 956                         skb->ip_summed = CHECKSUM_UNNECESSARY;
 957                         break;
 958                 }
 959
 960                 /* fall through */
 961         case CHECKSUM_NONE:
 962                 NAPI_GRO_CB(skb)->flush = 1;
 963                 return NULL;
 964         }
 965
 966         return tcp_gro_receive(head, skb);
 967 }
 968
 969 static int tcp6_gro_complete(struct sk_buff *skb)
 970 {
 971         const struct ipv6hdr *iph = ipv6_hdr(skb);
 972         struct tcphdr *th = tcp_hdr(skb);
 973
 974         th->check = ~tcp_v6_check(skb->len - skb_transport_offset(skb),
 975                                   &iph->saddr, &iph->daddr, 0);
 976         skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
 977
 978         return tcp_gro_complete(skb);
 979 }
 980
 981 static void tcp_v6_send_response(struct sk_buff *skb, u32 seq, u32 ack, u32 win,
 982                                  u32 ts, struct tcp_md5sig_key *key, int rst, u8 tclass)
 983 {
 984         const struct tcphdr *th = tcp_hdr(skb);
 985         struct tcphdr *t1;
 986         struct sk_buff *buff;
 987         struct flowi6 fl6;
 988         struct net *net = dev_net(skb_dst(skb)->dev);
 989         struct sock *ctl_sk = net->ipv6.tcp_sk;
 990         unsigned int tot_len = sizeof(struct tcphdr);
 991         struct dst_entry *dst;
 992         __be32 *topt;
 993
 994         if (ts)
 995                 tot_len += TCPOLEN_TSTAMP_ALIGNED;
 996 #ifdef CONFIG_TCP_MD5SIG
 997         if (key)
 998                 tot_len += TCPOLEN_MD5SIG_ALIGNED;
 999 #endif
1000
1001         buff = alloc_skb(MAX_HEADER + sizeof(struct ipv6hdr) + tot_len,
1002                          GFP_ATOMIC);
1003         if (buff == NULL)
1004                 return;
1005
1006         skb_reserve(buff, MAX_HEADER + sizeof(struct ipv6hdr) + tot_len);
1007
1008         t1 = (struct tcphdr *) skb_push(buff, tot_len);
1009         skb_reset_transport_header(buff);
1010
1011         /* Swap the send and the receive. */
1012         memset(t1, 0, sizeof(*t1));
1013         t1->dest = th->source;
1014         t1->source = th->dest;
1015         t1->doff = tot_len / 4;
1016         t1->seq = htonl(seq);
1017         t1->ack_seq = htonl(ack);
1018         t1->ack = !rst || !th->ack;
1019         t1->rst = rst;
1020         t1->window = htons(win);
1021
1022         topt = (__be32 *)(t1 + 1);
1023
1024         if (ts) {
1025                 *topt++ = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
1026                                 (TCPOPT_TIMESTAMP << 8) | TCPOLEN_TIMESTAMP);
1027                 *topt++ = htonl(tcp_time_stamp);
1028                 *topt++ = htonl(ts);
1029         }
1030
1031 #ifdef CONFIG_TCP_MD5SIG
1032         if (key) {
1033                 *topt++ = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
1034                                 (TCPOPT_MD5SIG << 8) | TCPOLEN_MD5SIG);
1035                 tcp_v6_md5_hash_hdr((__u8 *)topt, key,
1036                                     &ipv6_hdr(skb)->saddr,
1037                                     &ipv6_hdr(skb)->daddr, t1);
1038         }
1039 #endif
1040
1041         memset(&fl6, 0, sizeof(fl6));
1042         ipv6_addr_copy(&fl6.daddr, &ipv6_hdr(skb)->saddr);
1043         ipv6_addr_copy(&fl6.saddr, &ipv6_hdr(skb)->daddr);
1044
1045         buff->ip_summed = CHECKSUM_PARTIAL;
1046         buff->csum = 0;
1047
1048         __tcp_v6_send_check(buff, &fl6.saddr, &fl6.daddr);
1049
1050         fl6.flowi6_proto = IPPROTO_TCP;
1051         fl6.flowi6_oif = inet6_iif(skb);
1052         fl6.fl6_dport = t1->dest;
1053         fl6.fl6_sport = t1->source;
1054         security_skb_classify_flow(skb, flowi6_to_flowi(&fl6));
1055
1056         /* Pass a socket to ip6_dst_lookup either it is for RST
1057          * Underlying function will use this to retrieve the network
1058          * namespace
1059          */
1060         dst = ip6_dst_lookup_flow(ctl_sk, &fl6, NULL, false);
1061         if (!IS_ERR(dst)) {
1062                 skb_dst_set(buff, dst);
1063                 ip6_xmit(ctl_sk, buff, &fl6, NULL, tclass);
1064                 TCP_INC_STATS_BH(net, TCP_MIB_OUTSEGS);
1065                 if (rst)
1066                         TCP_INC_STATS_BH(net, TCP_MIB_OUTRSTS);
1067                 return;
1068         }
1069
1070         kfree_skb(buff);
1071 }
1072
1073 static void tcp_v6_send_reset(struct sock *sk, struct sk_buff *skb)
1074 {
1075         const struct tcphdr *th = tcp_hdr(skb);
1076         u32 seq = 0, ack_seq = 0;
1077         struct tcp_md5sig_key *key = NULL;
1078
1079         if (th->rst)
1080                 return;
1081
1082         if (!ipv6_unicast_destination(skb))
1083                 return;
1084
1085 #ifdef CONFIG_TCP_MD5SIG
1086         if (sk)
1087                 key = tcp_v6_md5_do_lookup(sk, &ipv6_hdr(skb)->daddr);
1088 #endif
1089
1090         if (th->ack)
1091                 seq = ntohl(th->ack_seq);
1092         else
1093                 ack_seq = ntohl(th->seq) + th->syn + th->fin + skb->len -
1094                           (th->doff << 2);
1095
1096         tcp_v6_send_response(skb, seq, ack_seq, 0, 0, key, 1, 0);
1097 }
1098
1099 static void tcp_v6_send_ack(struct sk_buff *skb, u32 seq, u32 ack, u32 win, u32 ts,
1100                             struct tcp_md5sig_key *key, u8 tclass)
1101 {
1102         tcp_v6_send_response(skb, seq, ack, win, ts, key, 0, tclass);
1103 }
1104
1105 static void tcp_v6_timewait_ack(struct sock *sk, struct sk_buff *skb)
1106 {
1107         struct inet_timewait_sock *tw = inet_twsk(sk);
1108         struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
1109
1110         tcp_v6_send_ack(skb, tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
1111                         tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
1112                         tcptw->tw_ts_recent, tcp_twsk_md5_key(tcptw),
1113                         tw->tw_tclass);
1114
1115         inet_twsk_put(tw);
1116 }
1117
1118 static void tcp_v6_reqsk_send_ack(struct sock *sk, struct sk_buff *skb,
1119                                   struct request_sock *req)
1120 {
1121         tcp_v6_send_ack(skb, tcp_rsk(req)->snt_isn + 1, tcp_rsk(req)->rcv_isn + 1, req->rcv_wnd, req->ts_recent,
1122                         tcp_v6_md5_do_lookup(sk, &ipv6_hdr(skb)->daddr), 0);
1123 }
1124
1125
1126 static struct sock *tcp_v6_hnd_req(struct sock *sk,struct sk_buff *skb)
1127 {
1128         struct request_sock *req, **prev;
1129         const struct tcphdr *th = tcp_hdr(skb);
1130         struct sock *nsk;
1131
1132         /* Find possible connection requests. */
1133         req = inet6_csk_search_req(sk, &prev, th->source,
1134                                    &ipv6_hdr(skb)->saddr,
1135                                    &ipv6_hdr(skb)->daddr, inet6_iif(skb));
1136         if (req)
1137                 return tcp_check_req(sk, skb, req, prev);
1138
1139         nsk = __inet6_lookup_established(sock_net(sk), &tcp_hashinfo,
1140                         &ipv6_hdr(skb)->saddr, th->source,
1141                         &ipv6_hdr(skb)->daddr, ntohs(th->dest), inet6_iif(skb));
1142
1143         if (nsk) {
1144                 if (nsk->sk_state != TCP_TIME_WAIT) {
1145                         bh_lock_sock(nsk);
1146                         return nsk;
1147                 }
1148                 inet_twsk_put(inet_twsk(nsk));
1149                 return NULL;
1150         }
1151
1152 #ifdef CONFIG_SYN_COOKIES
1153         if (!th->syn)
1154                 sk = cookie_v6_check(sk, skb);
1155 #endif
1156         return sk;
1157 }
1158
1159 /* FIXME: this is substantially similar to the ipv4 code.
1160  * Can some kind of merge be done? -- erics
1161  */
1162 static int tcp_v6_conn_request(struct sock *sk, struct sk_buff *skb)
1163 {
1164         struct tcp_extend_values tmp_ext;
1165         struct tcp_options_received tmp_opt;
1166         const u8 *hash_location;
1167         struct request_sock *req;
1168         struct inet6_request_sock *treq;
1169         struct ipv6_pinfo *np = inet6_sk(sk);
1170         struct tcp_sock *tp = tcp_sk(sk);
1171         __u32 isn = TCP_SKB_CB(skb)->when;
1172         struct dst_entry *dst = NULL;
1173         int want_cookie = 0;
1174
1175         if (skb->protocol == htons(ETH_P_IP))
1176                 return tcp_v4_conn_request(sk, skb);
1177
1178         if (!ipv6_unicast_destination(skb))
1179                 goto drop;
1180
1181         if (inet_csk_reqsk_queue_is_full(sk) && !isn) {
1182                 want_cookie = tcp_syn_flood_action(sk, skb, "TCPv6");
1183                 if (!want_cookie)
1184                         goto drop;
1185         }
1186
1187         if (sk_acceptq_is_full(sk) && inet_csk_reqsk_queue_young(sk) > 1)
1188                 goto drop;
1189
1190         req = inet6_reqsk_alloc(&tcp6_request_sock_ops);
1191         if (req == NULL)
1192                 goto drop;
1193
1194 #ifdef CONFIG_TCP_MD5SIG
1195         tcp_rsk(req)->af_specific = &tcp_request_sock_ipv6_ops;
1196 #endif
1197
1198         tcp_clear_options(&tmp_opt);
1199         tmp_opt.mss_clamp = IPV6_MIN_MTU - sizeof(struct tcphdr) - sizeof(struct ipv6hdr);
1200         tmp_opt.user_mss = tp->rx_opt.user_mss;
1201         tcp_parse_options(skb, &tmp_opt, &hash_location, 0);
1202
1203         if (tmp_opt.cookie_plus > 0 &&
1204             tmp_opt.saw_tstamp &&
1205             !tp->rx_opt.cookie_out_never &&
1206             (sysctl_tcp_cookie_size > 0 ||
1207              (tp->cookie_values != NULL &&
1208               tp->cookie_values->cookie_desired > 0))) {
1209                 u8 *c;
1210                 u32 *d;
1211                 u32 *mess = &tmp_ext.cookie_bakery[COOKIE_DIGEST_WORDS];
1212                 int l = tmp_opt.cookie_plus - TCPOLEN_COOKIE_BASE;
1213
1214                 if (tcp_cookie_generator(&tmp_ext.cookie_bakery[0]) != 0)
1215                         goto drop_and_free;
1216
1217                 /* Secret recipe starts with IP addresses */
1218                 d = (__force u32 *)&ipv6_hdr(skb)->daddr.s6_addr32[0];
1219                 *mess++ ^= *d++;
1220                 *mess++ ^= *d++;
1221                 *mess++ ^= *d++;
1222                 *mess++ ^= *d++;
1223                 d = (__force u32 *)&ipv6_hdr(skb)->saddr.s6_addr32[0];
1224                 *mess++ ^= *d++;
1225                 *mess++ ^= *d++;
1226                 *mess++ ^= *d++;
1227                 *mess++ ^= *d++;
1228
1229                 /* plus variable length Initiator Cookie */
1230                 c = (u8 *)mess;
1231                 while (l-- > 0)
1232                         *c++ ^= *hash_location++;
1233
1234                 want_cookie = 0;        /* not our kind of cookie */
1235                 tmp_ext.cookie_out_never = 0; /* false */
1236                 tmp_ext.cookie_plus = tmp_opt.cookie_plus;
1237         } else if (!tp->rx_opt.cookie_in_always) {
1238                 /* redundant indications, but ensure initialization. */
1239                 tmp_ext.cookie_out_never = 1; /* true */
1240                 tmp_ext.cookie_plus = 0;
1241         } else {
1242                 goto drop_and_free;
1243         }
1244         tmp_ext.cookie_in_always = tp->rx_opt.cookie_in_always;
1245
1246         if (want_cookie && !tmp_opt.saw_tstamp)
1247                 tcp_clear_options(&tmp_opt);
1248
1249         tmp_opt.tstamp_ok = tmp_opt.saw_tstamp;
1250         tcp_openreq_init(req, &tmp_opt, skb);
1251
1252         treq = inet6_rsk(req);
1253         ipv6_addr_copy(&treq->rmt_addr, &ipv6_hdr(skb)->saddr);
1254         ipv6_addr_copy(&treq->loc_addr, &ipv6_hdr(skb)->daddr);
1255         if (!want_cookie || tmp_opt.tstamp_ok)
1256                 TCP_ECN_create_request(req, tcp_hdr(skb));
1257
1258         if (!isn) {
1259                 struct inet_peer *peer = NULL;
1260
1261                 if (ipv6_opt_accepted(sk, skb) ||
1262                     np->rxopt.bits.rxinfo || np->rxopt.bits.rxoinfo ||
1263                     np->rxopt.bits.rxhlim || np->rxopt.bits.rxohlim) {
1264                         atomic_inc(&skb->users);
1265                         treq->pktopts = skb;
1266                 }
1267                 treq->iif = sk->sk_bound_dev_if;
1268
1269                 /* So that link locals have meaning */
1270                 if (!sk->sk_bound_dev_if &&
1271                     ipv6_addr_type(&treq->rmt_addr) & IPV6_ADDR_LINKLOCAL)
1272                         treq->iif = inet6_iif(skb);
1273
1274                 if (want_cookie) {
1275                         isn = cookie_v6_init_sequence(sk, skb, &req->mss);
1276                         req->cookie_ts = tmp_opt.tstamp_ok;
1277                         goto have_isn;
1278                 }
1279
1280                 /* VJ's idea. We save last timestamp seen
1281                  * from the destination in peer table, when entering
1282                  * state TIME-WAIT, and check against it before
1283                  * accepting new connection request.
1284                  *
1285                  * If "isn" is not zero, this request hit alive
1286                  * timewait bucket, so that all the necessary checks
1287                  * are made in the function processing timewait state.
1288                  */
1289                 if (tmp_opt.saw_tstamp &&
1290                     tcp_death_row.sysctl_tw_recycle &&
1291                     (dst = inet6_csk_route_req(sk, req)) != NULL &&
1292                     (peer = rt6_get_peer((struct rt6_info *)dst)) != NULL &&
1293                     ipv6_addr_equal((struct in6_addr *)peer->daddr.addr.a6,
1294                                     &treq->rmt_addr)) {
1295                         inet_peer_refcheck(peer);
1296                         if ((u32)get_seconds() - peer->tcp_ts_stamp < TCP_PAWS_MSL &&
1297                             (s32)(peer->tcp_ts - req->ts_recent) >
1298                                                         TCP_PAWS_WINDOW) {
1299                                 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_PAWSPASSIVEREJECTED);
1300                                 goto drop_and_release;
1301                         }
1302                 }
1303                 /* Kill the following clause, if you dislike this way. */
1304                 else if (!sysctl_tcp_syncookies &&
1305                          (sysctl_max_syn_backlog - inet_csk_reqsk_queue_len(sk) <
1306                           (sysctl_max_syn_backlog >> 2)) &&
1307                          (!peer || !peer->tcp_ts_stamp) &&
1308                          (!dst || !dst_metric(dst, RTAX_RTT))) {
1309                         /* Without syncookies last quarter of
1310                          * backlog is filled with destinations,
1311                          * proven to be alive.
1312                          * It means that we continue to communicate
1313                          * to destinations, already remembered
1314                          * to the moment of synflood.
1315                          */
1316                         LIMIT_NETDEBUG(KERN_DEBUG "TCP: drop open request from %pI6/%u\n",
1317                                        &treq->rmt_addr, ntohs(tcp_hdr(skb)->source));
1318                         goto drop_and_release;
1319                 }
1320
1321                 isn = tcp_v6_init_sequence(skb);
1322         }
1323 have_isn:
1324         tcp_rsk(req)->snt_isn = isn;
1325         tcp_rsk(req)->snt_synack = tcp_time_stamp;
1326
1327         security_inet_conn_request(sk, skb, req);
1328
1329         if (tcp_v6_send_synack(sk, req,
1330                                (struct request_values *)&tmp_ext) ||
1331             want_cookie)
1332                 goto drop_and_free;
1333
1334         inet6_csk_reqsk_queue_hash_add(sk, req, TCP_TIMEOUT_INIT);
1335         return 0;
1336
1337 drop_and_release:
1338         dst_release(dst);
1339 drop_and_free:
1340         reqsk_free(req);
1341 drop:
1342         return 0; /* don't send reset */
1343 }
1344
1345 static struct sock * tcp_v6_syn_recv_sock(struct sock *sk, struct sk_buff *skb,
1346                                           struct request_sock *req,
1347                                           struct dst_entry *dst)
1348 {
1349         struct inet6_request_sock *treq;
1350         struct ipv6_pinfo *newnp, *np = inet6_sk(sk);
1351         struct tcp6_sock *newtcp6sk;
1352         struct inet_sock *newinet;
1353         struct tcp_sock *newtp;
1354         struct sock *newsk;
1355         struct ipv6_txoptions *opt;
1356 #ifdef CONFIG_TCP_MD5SIG
1357         struct tcp_md5sig_key *key;
1358 #endif
1359
1360         if (skb->protocol == htons(ETH_P_IP)) {
1361                 /*
1362                  *      v6 mapped
1363                  */
1364
1365                 newsk = tcp_v4_syn_recv_sock(sk, skb, req, dst);
1366
1367                 if (newsk == NULL)
1368                         return NULL;
1369
1370                 newtcp6sk = (struct tcp6_sock *)newsk;
1371                 inet_sk(newsk)->pinet6 = &newtcp6sk->inet6;
1372
1373                 newinet = inet_sk(newsk);
1374                 newnp = inet6_sk(newsk);
1375                 newtp = tcp_sk(newsk);
1376
1377                 memcpy(newnp, np, sizeof(struct ipv6_pinfo));
1378
1379                 ipv6_addr_set_v4mapped(newinet->inet_daddr, &newnp->daddr);
1380
1381                 ipv6_addr_set_v4mapped(newinet->inet_saddr, &newnp->saddr);
1382
1383                 ipv6_addr_copy(&newnp->rcv_saddr, &newnp->saddr);
1384
1385                 inet_csk(newsk)->icsk_af_ops = &ipv6_mapped;
1386                 newsk->sk_backlog_rcv = tcp_v4_do_rcv;
1387 #ifdef CONFIG_TCP_MD5SIG
1388                 newtp->af_specific = &tcp_sock_ipv6_mapped_specific;
1389 #endif
1390
1391                 newnp->ipv6_ac_list = NULL;
1392                 newnp->ipv6_fl_list = NULL;
1393                 newnp->pktoptions  = NULL;
1394                 newnp->opt         = NULL;
1395                 newnp->mcast_oif   = inet6_iif(skb);
1396                 newnp->mcast_hops  = ipv6_hdr(skb)->hop_limit;
1397
1398                 /*
1399                  * No need to charge this sock to the relevant IPv6 refcnt debug socks count
1400                  * here, tcp_create_openreq_child now does this for us, see the comment in
1401                  * that function for the gory details. -acme
1402                  */
1403
1404                 /* It is tricky place. Until this moment IPv4 tcp
1405                    worked with IPv6 icsk.icsk_af_ops.
1406                    Sync it now.
1407                  */
1408                 tcp_sync_mss(newsk, inet_csk(newsk)->icsk_pmtu_cookie);
1409
1410                 return newsk;
1411         }
1412
1413         treq = inet6_rsk(req);
1414         opt = np->opt;
1415
1416         if (sk_acceptq_is_full(sk))
1417                 goto out_overflow;
1418
1419         if (!dst) {
1420                 dst = inet6_csk_route_req(sk, req);
1421                 if (!dst)
1422                         goto out;
1423         }
1424
1425         newsk = tcp_create_openreq_child(sk, req, skb);
1426         if (newsk == NULL)
1427                 goto out_nonewsk;
1428
1429         /*
1430          * No need to charge this sock to the relevant IPv6 refcnt debug socks
1431          * count here, tcp_create_openreq_child now does this for us, see the
1432          * comment in that function for the gory details. -acme
1433          */
1434
1435         newsk->sk_gso_type = SKB_GSO_TCPV6;
1436         __ip6_dst_store(newsk, dst, NULL, NULL);
1437
1438         newtcp6sk = (struct tcp6_sock *)newsk;
1439         inet_sk(newsk)->pinet6 = &newtcp6sk->inet6;
1440
1441         newtp = tcp_sk(newsk);
1442         newinet = inet_sk(newsk);
1443         newnp = inet6_sk(newsk);
1444
1445         memcpy(newnp, np, sizeof(struct ipv6_pinfo));
1446
1447         ipv6_addr_copy(&newnp->daddr, &treq->rmt_addr);
1448         ipv6_addr_copy(&newnp->saddr, &treq->loc_addr);
1449         ipv6_addr_copy(&newnp->rcv_saddr, &treq->loc_addr);
1450         newsk->sk_bound_dev_if = treq->iif;
1451
1452         /* Now IPv6 options...
1453
1454            First: no IPv4 options.
1455          */
1456         newinet->inet_opt = NULL;
1457         newnp->ipv6_ac_list = NULL;
1458         newnp->ipv6_fl_list = NULL;
1459
1460         /* Clone RX bits */
1461         newnp->rxopt.all = np->rxopt.all;
1462
1463         /* Clone pktoptions received with SYN */
1464         newnp->pktoptions = NULL;
1465         if (treq->pktopts != NULL) {
1466                 newnp->pktoptions = skb_clone(treq->pktopts, GFP_ATOMIC);
1467                 kfree_skb(treq->pktopts);
1468                 treq->pktopts = NULL;
1469                 if (newnp->pktoptions)
1470                         skb_set_owner_r(newnp->pktoptions, newsk);
1471         }
1472         newnp->opt        = NULL;
1473         newnp->mcast_oif  = inet6_iif(skb);
1474         newnp->mcast_hops = ipv6_hdr(skb)->hop_limit;
1475
1476         /* Clone native IPv6 options from listening socket (if any)
1477
1478            Yes, keeping reference count would be much more clever,
1479            but we make one more one thing there: reattach optmem
1480            to newsk.
1481          */
1482         if (opt) {
1483                 newnp->opt = ipv6_dup_options(newsk, opt);
1484                 if (opt != np->opt)
1485                         sock_kfree_s(sk, opt, opt->tot_len);
1486         }
1487
1488         inet_csk(newsk)->icsk_ext_hdr_len = 0;
1489         if (newnp->opt)
1490                 inet_csk(newsk)->icsk_ext_hdr_len = (newnp->opt->opt_nflen +
1491                                                      newnp->opt->opt_flen);
1492
1493         tcp_mtup_init(newsk);
1494         tcp_sync_mss(newsk, dst_mtu(dst));
1495         newtp->advmss = dst_metric_advmss(dst);
1496         tcp_initialize_rcv_mss(newsk);
1497         if (tcp_rsk(req)->snt_synack)
1498                 tcp_valid_rtt_meas(newsk,
1499                     tcp_time_stamp - tcp_rsk(req)->snt_synack);
1500         newtp->total_retrans = req->retrans;
1501
1502         newinet->inet_daddr = newinet->inet_saddr = LOOPBACK4_IPV6;
1503         newinet->inet_rcv_saddr = LOOPBACK4_IPV6;
1504
1505 #ifdef CONFIG_TCP_MD5SIG
1506         /* Copy over the MD5 key from the original socket */
1507         if ((key = tcp_v6_md5_do_lookup(sk, &newnp->daddr)) != NULL) {
1508                 /* We're using one, so create a matching key
1509                  * on the newsk structure. If we fail to get
1510                  * memory, then we end up not copying the key
1511                  * across. Shucks.
1512                  */
1513                 char *newkey = kmemdup(key->key, key->keylen, GFP_ATOMIC);
1514                 if (newkey != NULL)
1515                         tcp_v6_md5_do_add(newsk, &newnp->daddr,
1516                                           newkey, key->keylen);
1517         }
1518 #endif
1519
1520         if (__inet_inherit_port(sk, newsk) < 0) {
1521                 sock_put(newsk);
1522                 goto out;
1523         }
1524         __inet6_hash(newsk, NULL);
1525
1526         return newsk;
1527
1528 out_overflow:
1529         NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
1530 out_nonewsk:
1531         if (opt && opt != np->opt)
1532                 sock_kfree_s(sk, opt, opt->tot_len);
1533         dst_release(dst);
1534 out:
1535         NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
1536         return NULL;
1537 }
1538
1539 static __sum16 tcp_v6_checksum_init(struct sk_buff *skb)
1540 {
1541         if (skb->ip_summed == CHECKSUM_COMPLETE) {
1542                 if (!tcp_v6_check(skb->len, &ipv6_hdr(skb)->saddr,
1543                                   &ipv6_hdr(skb)->daddr, skb->csum)) {
1544                         skb->ip_summed = CHECKSUM_UNNECESSARY;
1545                         return 0;
1546                 }
1547         }
1548
1549         skb->csum = ~csum_unfold(tcp_v6_check(skb->len,
1550                                               &ipv6_hdr(skb)->saddr,
1551                                               &ipv6_hdr(skb)->daddr, 0));
1552
1553         if (skb->len <= 76) {
1554                 return __skb_checksum_complete(skb);
1555         }
1556         return 0;
1557 }
1558
1559 /* The socket must have it's spinlock held when we get
1560  * here.
1561  *
1562  * We have a potential double-lock case here, so even when
1563  * doing backlog processing we use the BH locking scheme.
1564  * This is because we cannot sleep with the original spinlock
1565  * held.
1566  */
1567 static int tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb)
1568 {
1569         struct ipv6_pinfo *np = inet6_sk(sk);
1570         struct tcp_sock *tp;
1571         struct sk_buff *opt_skb = NULL;
1572
1573         /* Imagine: socket is IPv6. IPv4 packet arrives,
1574            goes to IPv4 receive handler and backlogged.
1575            From backlog it always goes here. Kerboom...
1576            Fortunately, tcp_rcv_established and rcv_established
1577            handle them correctly, but it is not case with
1578            tcp_v6_hnd_req and tcp_v6_send_reset().   --ANK
1579          */
1580
1581         if (skb->protocol == htons(ETH_P_IP))
1582                 return tcp_v4_do_rcv(sk, skb);
1583
1584 #ifdef CONFIG_TCP_MD5SIG
1585         if (tcp_v6_inbound_md5_hash (sk, skb))
1586                 goto discard;
1587 #endif
1588
1589         if (sk_filter(sk, skb))
1590                 goto discard;
1591
1592         /*
1593          *      socket locking is here for SMP purposes as backlog rcv
1594          *      is currently called with bh processing disabled.
1595          */
1596
1597         /* Do Stevens' IPV6_PKTOPTIONS.
1598
1599            Yes, guys, it is the only place in our code, where we
1600            may make it not affecting IPv4.
1601            The rest of code is protocol independent,
1602            and I do not like idea to uglify IPv4.
1603
1604            Actually, all the idea behind IPV6_PKTOPTIONS
1605            looks not very well thought. For now we latch
1606            options, received in the last packet, enqueued
1607            by tcp. Feel free to propose better solution.
1608                                                --ANK (980728)
1609          */
1610         if (np->rxopt.all)
1611                 opt_skb = skb_clone(skb, GFP_ATOMIC);
1612
1613         if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
1614                 sock_rps_save_rxhash(sk, skb);
1615                 if (tcp_rcv_established(sk, skb, tcp_hdr(skb), skb->len))
1616                         goto reset;
1617                 if (opt_skb)
1618                         goto ipv6_pktoptions;
1619                 return 0;
1620         }
1621
1622         if (skb->len < tcp_hdrlen(skb) || tcp_checksum_complete(skb))
1623                 goto csum_err;
1624
1625         if (sk->sk_state == TCP_LISTEN) {
1626                 struct sock *nsk = tcp_v6_hnd_req(sk, skb);
1627                 if (!nsk)
1628                         goto discard;
1629
1630                 /*
1631                  * Queue it on the new socket if the new socket is active,
1632                  * otherwise we just shortcircuit this and continue with
1633                  * the new socket..
1634                  */
1635                 if(nsk != sk) {
1636                         sock_rps_save_rxhash(nsk, skb);
1637                         if (tcp_child_process(sk, nsk, skb))
1638                                 goto reset;
1639                         if (opt_skb)
1640                                 __kfree_skb(opt_skb);
1641                         return 0;
1642                 }
1643         } else
1644                 sock_rps_save_rxhash(sk, skb);
1645
1646         if (tcp_rcv_state_process(sk, skb, tcp_hdr(skb), skb->len))
1647                 goto reset;
1648         if (opt_skb)
1649                 goto ipv6_pktoptions;
1650         return 0;
1651
1652 reset:
1653         tcp_v6_send_reset(sk, skb);
1654 discard:
1655         if (opt_skb)
1656                 __kfree_skb(opt_skb);
1657         kfree_skb(skb);
1658         return 0;
1659 csum_err:
1660         TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_INERRS);
1661         goto discard;
1662
1663
1664 ipv6_pktoptions:
1665         /* Do you ask, what is it?
1666
1667            1. skb was enqueued by tcp.
1668            2. skb is added to tail of read queue, rather than out of order.
1669            3. socket is not in passive state.
1670            4. Finally, it really contains options, which user wants to receive.
1671          */
1672         tp = tcp_sk(sk);
1673         if (TCP_SKB_CB(opt_skb)->end_seq == tp->rcv_nxt &&
1674             !((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN))) {
1675                 if (np->rxopt.bits.rxinfo || np->rxopt.bits.rxoinfo)
1676                         np->mcast_oif = inet6_iif(opt_skb);
1677                 if (np->rxopt.bits.rxhlim || np->rxopt.bits.rxohlim)
1678                         np->mcast_hops = ipv6_hdr(opt_skb)->hop_limit;
1679                 if (ipv6_opt_accepted(sk, opt_skb)) {
1680                         skb_set_owner_r(opt_skb, sk);
1681                         opt_skb = xchg(&np->pktoptions, opt_skb);
1682                 } else {
1683                         __kfree_skb(opt_skb);
1684                         opt_skb = xchg(&np->pktoptions, NULL);
1685                 }
1686         }
1687
1688         kfree_skb(opt_skb);
1689         return 0;
1690 }
1691
1692 static int tcp_v6_rcv(struct sk_buff *skb)
1693 {
1694         const struct tcphdr *th;
1695         const struct ipv6hdr *hdr;
1696         struct sock *sk;
1697         int ret;
1698         struct net *net = dev_net(skb->dev);
1699
1700         if (skb->pkt_type != PACKET_HOST)
1701                 goto discard_it;
1702
1703         /*
1704          *      Count it even if it's bad.
1705          */
1706         TCP_INC_STATS_BH(net, TCP_MIB_INSEGS);
1707
1708         if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
1709                 goto discard_it;
1710
1711         th = tcp_hdr(skb);
1712
1713         if (th->doff < sizeof(struct tcphdr)/4)
1714                 goto bad_packet;
1715         if (!pskb_may_pull(skb, th->doff*4))
1716                 goto discard_it;
1717
1718         if (!skb_csum_unnecessary(skb) && tcp_v6_checksum_init(skb))
1719                 goto bad_packet;
1720
1721         th = tcp_hdr(skb);
1722         hdr = ipv6_hdr(skb);
1723         TCP_SKB_CB(skb)->seq = ntohl(th->seq);
1724         TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
1725                                     skb->len - th->doff*4);
1726         TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
1727         TCP_SKB_CB(skb)->when = 0;
1728         TCP_SKB_CB(skb)->ip_dsfield = ipv6_get_dsfield(hdr);
1729         TCP_SKB_CB(skb)->sacked = 0;
1730
1731         sk = __inet6_lookup_skb(&tcp_hashinfo, skb, th->source, th->dest);
1732         if (!sk)
1733                 goto no_tcp_socket;
1734
1735 process:
1736         if (sk->sk_state == TCP_TIME_WAIT)
1737                 goto do_time_wait;
1738
1739         if (hdr->hop_limit < inet6_sk(sk)->min_hopcount) {
1740                 NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP);
1741                 goto discard_and_relse;
1742         }
1743
1744         if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb))
1745                 goto discard_and_relse;
1746
1747         if (sk_filter(sk, skb))
1748                 goto discard_and_relse;
1749
1750         skb->dev = NULL;
1751
1752         bh_lock_sock_nested(sk);
1753         ret = 0;
1754         if (!sock_owned_by_user(sk)) {
1755 #ifdef CONFIG_NET_DMA
1756                 struct tcp_sock *tp = tcp_sk(sk);
1757                 if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list)
1758                         tp->ucopy.dma_chan = dma_find_channel(DMA_MEMCPY);
1759                 if (tp->ucopy.dma_chan)
1760                         ret = tcp_v6_do_rcv(sk, skb);
1761                 else
1762 #endif
1763                 {
1764                         if (!tcp_prequeue(sk, skb))
1765                                 ret = tcp_v6_do_rcv(sk, skb);
1766                 }
1767         } else if (unlikely(sk_add_backlog(sk, skb))) {
1768                 bh_unlock_sock(sk);
1769                 NET_INC_STATS_BH(net, LINUX_MIB_TCPBACKLOGDROP);
1770                 goto discard_and_relse;
1771         }
1772         bh_unlock_sock(sk);
1773
1774         sock_put(sk);
1775         return ret ? -1 : 0;
1776
1777 no_tcp_socket:
1778         if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb))
1779                 goto discard_it;
1780
1781         if (skb->len < (th->doff<<2) || tcp_checksum_complete(skb)) {
1782 bad_packet:
1783                 TCP_INC_STATS_BH(net, TCP_MIB_INERRS);
1784         } else {
1785                 tcp_v6_send_reset(NULL, skb);
1786         }
1787
1788 discard_it:
1789
1790         /*
1791          *      Discard frame
1792          */
1793
1794         kfree_skb(skb);
1795         return 0;
1796
1797 discard_and_relse:
1798         sock_put(sk);
1799         goto discard_it;
1800
1801 do_time_wait:
1802         if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
1803                 inet_twsk_put(inet_twsk(sk));
1804                 goto discard_it;
1805         }
1806
1807         if (skb->len < (th->doff<<2) || tcp_checksum_complete(skb)) {
1808                 TCP_INC_STATS_BH(net, TCP_MIB_INERRS);
1809                 inet_twsk_put(inet_twsk(sk));
1810                 goto discard_it;
1811         }
1812
1813         switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) {
1814         case TCP_TW_SYN:
1815         {
1816                 struct sock *sk2;
1817
1818                 sk2 = inet6_lookup_listener(dev_net(skb->dev), &tcp_hashinfo,
1819                                             &ipv6_hdr(skb)->daddr,
1820                                             ntohs(th->dest), inet6_iif(skb));
1821                 if (sk2 != NULL) {
1822                         struct inet_timewait_sock *tw = inet_twsk(sk);
1823                         inet_twsk_deschedule(tw, &tcp_death_row);
1824                         inet_twsk_put(tw);
1825                         sk = sk2;
1826                         goto process;
1827                 }
1828                 /* Fall through to ACK */
1829         }
1830         case TCP_TW_ACK:
1831                 tcp_v6_timewait_ack(sk, skb);
1832                 break;
1833         case TCP_TW_RST:
1834                 goto no_tcp_socket;
1835         case TCP_TW_SUCCESS:;
1836         }
1837         goto discard_it;
1838 }
1839
1840 static struct inet_peer *tcp_v6_get_peer(struct sock *sk, bool *release_it)
1841 {
1842         struct rt6_info *rt = (struct rt6_info *) __sk_dst_get(sk);
1843         struct ipv6_pinfo *np = inet6_sk(sk);
1844         struct inet_peer *peer;
1845
1846         if (!rt ||
1847             !ipv6_addr_equal(&np->daddr, &rt->rt6i_dst.addr)) {
1848                 peer = inet_getpeer_v6(&np->daddr, 1);
1849                 *release_it = true;
1850         } else {
1851                 if (!rt->rt6i_peer)
1852                         rt6_bind_peer(rt, 1);
1853                 peer = rt->rt6i_peer;
1854                 *release_it = false;
1855         }
1856
1857         return peer;
1858 }
1859
1860 static void *tcp_v6_tw_get_peer(struct sock *sk)
1861 {
1862         const struct inet6_timewait_sock *tw6 = inet6_twsk(sk);
1863         const struct inet_timewait_sock *tw = inet_twsk(sk);
1864
1865         if (tw->tw_family == AF_INET)
1866                 return tcp_v4_tw_get_peer(sk);
1867
1868         return inet_getpeer_v6(&tw6->tw_v6_daddr, 1);
1869 }
1870
1871 static struct timewait_sock_ops tcp6_timewait_sock_ops = {
1872         .twsk_obj_size  = sizeof(struct tcp6_timewait_sock),
1873         .twsk_unique    = tcp_twsk_unique,
1874         .twsk_destructor= tcp_twsk_destructor,
1875         .twsk_getpeer   = tcp_v6_tw_get_peer,
1876 };
1877
1878 static const struct inet_connection_sock_af_ops ipv6_specific = {
1879         .queue_xmit        = inet6_csk_xmit,
1880         .send_check        = tcp_v6_send_check,
1881         .rebuild_header    = inet6_sk_rebuild_header,
1882         .conn_request      = tcp_v6_conn_request,
1883         .syn_recv_sock     = tcp_v6_syn_recv_sock,
1884         .get_peer          = tcp_v6_get_peer,
1885         .net_header_len    = sizeof(struct ipv6hdr),
1886         .setsockopt        = ipv6_setsockopt,
1887         .getsockopt        = ipv6_getsockopt,
1888         .addr2sockaddr     = inet6_csk_addr2sockaddr,
1889         .sockaddr_len      = sizeof(struct sockaddr_in6),
1890         .bind_conflict     = inet6_csk_bind_conflict,
1891 #ifdef CONFIG_COMPAT
1892         .compat_setsockopt = compat_ipv6_setsockopt,
1893         .compat_getsockopt = compat_ipv6_getsockopt,
1894 #endif
1895 };
1896
1897 #ifdef CONFIG_TCP_MD5SIG
1898 static const struct tcp_sock_af_ops tcp_sock_ipv6_specific = {
1899         .md5_lookup     =       tcp_v6_md5_lookup,
1900         .calc_md5_hash  =       tcp_v6_md5_hash_skb,
1901         .md5_add        =       tcp_v6_md5_add_func,
1902         .md5_parse      =       tcp_v6_parse_md5_keys,
1903 };
1904 #endif
1905
1906 /*
1907  *      TCP over IPv4 via INET6 API
1908  */
1909
1910 static const struct inet_connection_sock_af_ops ipv6_mapped = {
1911         .queue_xmit        = ip_queue_xmit,
1912         .send_check        = tcp_v4_send_check,
1913         .rebuild_header    = inet_sk_rebuild_header,
1914         .conn_request      = tcp_v6_conn_request,
1915         .syn_recv_sock     = tcp_v6_syn_recv_sock,
1916         .get_peer          = tcp_v4_get_peer,
1917         .net_header_len    = sizeof(struct iphdr),
1918         .setsockopt        = ipv6_setsockopt,
1919         .getsockopt        = ipv6_getsockopt,
1920         .addr2sockaddr     = inet6_csk_addr2sockaddr,
1921         .sockaddr_len      = sizeof(struct sockaddr_in6),
1922         .bind_conflict     = inet6_csk_bind_conflict,
1923 #ifdef CONFIG_COMPAT
1924         .compat_setsockopt = compat_ipv6_setsockopt,
1925         .compat_getsockopt = compat_ipv6_getsockopt,
1926 #endif
1927 };
1928
1929 #ifdef CONFIG_TCP_MD5SIG
1930 static const struct tcp_sock_af_ops tcp_sock_ipv6_mapped_specific = {
1931         .md5_lookup     =       tcp_v4_md5_lookup,
1932         .calc_md5_hash  =       tcp_v4_md5_hash_skb,
1933         .md5_add        =       tcp_v6_md5_add_func,
1934         .md5_parse      =       tcp_v6_parse_md5_keys,
1935 };
1936 #endif
1937
1938 /* NOTE: A lot of things set to zero explicitly by call to
1939  *       sk_alloc() so need not be done here.
1940  */
1941 static int tcp_v6_init_sock(struct sock *sk)
1942 {
1943         struct inet_connection_sock *icsk = inet_csk(sk);
1944         struct tcp_sock *tp = tcp_sk(sk);
1945
1946         skb_queue_head_init(&tp->out_of_order_queue);
1947         tcp_init_xmit_timers(sk);
1948         tcp_prequeue_init(tp);
1949
1950         icsk->icsk_rto = TCP_TIMEOUT_INIT;
1951         tp->mdev = TCP_TIMEOUT_INIT;
1952
1953         /* So many TCP implementations out there (incorrectly) count the
1954          * initial SYN frame in their delayed-ACK and congestion control
1955          * algorithms that we must have the following bandaid to talk
1956          * efficiently to them.  -DaveM
1957          */
1958         tp->snd_cwnd = 2;
1959
1960         /* See draft-stevens-tcpca-spec-01 for discussion of the
1961          * initialization of these values.
1962          */
1963         tp->snd_ssthresh = TCP_INFINITE_SSTHRESH;
1964         tp->snd_cwnd_clamp = ~0;
1965         tp->mss_cache = TCP_MSS_DEFAULT;
1966
1967         tp->reordering = sysctl_tcp_reordering;
1968
1969         sk->sk_state = TCP_CLOSE;
1970
1971         icsk->icsk_af_ops = &ipv6_specific;
1972         icsk->icsk_ca_ops = &tcp_init_congestion_ops;
1973         icsk->icsk_sync_mss = tcp_sync_mss;
1974         sk->sk_write_space = sk_stream_write_space;
1975         sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
1976
1977 #ifdef CONFIG_TCP_MD5SIG
1978         tp->af_specific = &tcp_sock_ipv6_specific;
1979 #endif
1980
1981         /* TCP Cookie Transactions */
1982         if (sysctl_tcp_cookie_size > 0) {
1983                 /* Default, cookies without s_data_payload. */
1984                 tp->cookie_values =
1985                         kzalloc(sizeof(*tp->cookie_values),
1986                                 sk->sk_allocation);
1987                 if (tp->cookie_values != NULL)
1988                         kref_init(&tp->cookie_values->kref);
1989         }
1990         /* Presumed zeroed, in order of appearance:
1991          *      cookie_in_always, cookie_out_never,
1992          *      s_data_constant, s_data_in, s_data_out
1993          */
1994         sk->sk_sndbuf = sysctl_tcp_wmem[1];
1995         sk->sk_rcvbuf = sysctl_tcp_rmem[1];
1996
1997         local_bh_disable();
1998         percpu_counter_inc(&tcp_sockets_allocated);
1999         local_bh_enable();
2000
2001         return 0;
2002 }
2003
2004 static void tcp_v6_destroy_sock(struct sock *sk)
2005 {
2006 #ifdef CONFIG_TCP_MD5SIG
2007         /* Clean up the MD5 key list */
2008         if (tcp_sk(sk)->md5sig_info)
2009                 tcp_v6_clear_md5_list(sk);
2010 #endif
2011         tcp_v4_destroy_sock(sk);
2012         inet6_destroy_sock(sk);
2013 }
2014
2015 #ifdef CONFIG_PROC_FS
2016 /* Proc filesystem TCPv6 sock list dumping. */
2017 static void get_openreq6(struct seq_file *seq,
2018                          const struct sock *sk, struct request_sock *req, int i, int uid)
2019 {
2020         int ttd = req->expires - jiffies;
2021         const struct in6_addr *src = &inet6_rsk(req)->loc_addr;
2022         const struct in6_addr *dest = &inet6_rsk(req)->rmt_addr;
2023
2024         if (ttd < 0)
2025                 ttd = 0;
2026
2027         seq_printf(seq,
2028                    "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
2029                    "%02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK\n",
2030                    i,
2031                    src->s6_addr32[0], src->s6_addr32[1],
2032                    src->s6_addr32[2], src->s6_addr32[3],
2033                    ntohs(inet_rsk(req)->loc_port),
2034                    dest->s6_addr32[0], dest->s6_addr32[1],
2035                    dest->s6_addr32[2], dest->s6_addr32[3],
2036                    ntohs(inet_rsk(req)->rmt_port),
2037                    TCP_SYN_RECV,
2038                    0,0, /* could print option size, but that is af dependent. */
2039                    1,   /* timers active (only the expire timer) */
2040                    jiffies_to_clock_t(ttd),
2041                    req->retrans,
2042                    uid,
2043                    0,  /* non standard timer */
2044                    0, /* open_requests have no inode */
2045                    0, req);
2046 }
2047
2048 static void get_tcp6_sock(struct seq_file *seq, struct sock *sp, int i)
2049 {
2050         const struct in6_addr *dest, *src;
2051         __u16 destp, srcp;
2052         int timer_active;
2053         unsigned long timer_expires;
2054         const struct inet_sock *inet = inet_sk(sp);
2055         const struct tcp_sock *tp = tcp_sk(sp);
2056         const struct inet_connection_sock *icsk = inet_csk(sp);
2057         const struct ipv6_pinfo *np = inet6_sk(sp);
2058
2059         dest  = &np->daddr;
2060         src   = &np->rcv_saddr;
2061         destp = ntohs(inet->inet_dport);
2062         srcp  = ntohs(inet->inet_sport);
2063
2064         if (icsk->icsk_pending == ICSK_TIME_RETRANS) {
2065                 timer_active    = 1;
2066                 timer_expires   = icsk->icsk_timeout;
2067         } else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
2068                 timer_active    = 4;
2069                 timer_expires   = icsk->icsk_timeout;
2070         } else if (timer_pending(&sp->sk_timer)) {
2071                 timer_active    = 2;
2072                 timer_expires   = sp->sk_timer.expires;
2073         } else {
2074                 timer_active    = 0;
2075                 timer_expires = jiffies;
2076         }
2077
2078         seq_printf(seq,
2079                    "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
2080                    "%02X %08X:%08X %02X:%08lX %08X %5d %8d %lu %d %pK %lu %lu %u %u %d\n",
2081                    i,
2082                    src->s6_addr32[0], src->s6_addr32[1],
2083                    src->s6_addr32[2], src->s6_addr32[3], srcp,
2084                    dest->s6_addr32[0], dest->s6_addr32[1],
2085                    dest->s6_addr32[2], dest->s6_addr32[3], destp,
2086                    sp->sk_state,
2087                    tp->write_seq-tp->snd_una,
2088                    (sp->sk_state == TCP_LISTEN) ? sp->sk_ack_backlog : (tp->rcv_nxt - tp->copied_seq),
2089                    timer_active,
2090                    jiffies_to_clock_t(timer_expires - jiffies),
2091                    icsk->icsk_retransmits,
2092                    sock_i_uid(sp),
2093                    icsk->icsk_probes_out,
2094                    sock_i_ino(sp),
2095                    atomic_read(&sp->sk_refcnt), sp,
2096                    jiffies_to_clock_t(icsk->icsk_rto),
2097                    jiffies_to_clock_t(icsk->icsk_ack.ato),
2098                    (icsk->icsk_ack.quick << 1 ) | icsk->icsk_ack.pingpong,
2099                    tp->snd_cwnd,
2100                    tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh
2101                    );
2102 }
2103
2104 static void get_timewait6_sock(struct seq_file *seq,
2105                                struct inet_timewait_sock *tw, int i)
2106 {
2107         const struct in6_addr *dest, *src;
2108         __u16 destp, srcp;
2109         const struct inet6_timewait_sock *tw6 = inet6_twsk((struct sock *)tw);
2110         int ttd = tw->tw_ttd - jiffies;
2111
2112         if (ttd < 0)
2113                 ttd = 0;
2114
2115         dest = &tw6->tw_v6_daddr;
2116         src  = &tw6->tw_v6_rcv_saddr;
2117         destp = ntohs(tw->tw_dport);
2118         srcp  = ntohs(tw->tw_sport);
2119
2120         seq_printf(seq,
2121                    "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
2122                    "%02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK\n",
2123                    i,
2124                    src->s6_addr32[0], src->s6_addr32[1],
2125                    src->s6_addr32[2], src->s6_addr32[3], srcp,
2126                    dest->s6_addr32[0], dest->s6_addr32[1],
2127                    dest->s6_addr32[2], dest->s6_addr32[3], destp,
2128                    tw->tw_substate, 0, 0,
2129                    3, jiffies_to_clock_t(ttd), 0, 0, 0, 0,
2130                    atomic_read(&tw->tw_refcnt), tw);
2131 }
2132
2133 static int tcp6_seq_show(struct seq_file *seq, void *v)
2134 {
2135         struct tcp_iter_state *st;
2136
2137         if (v == SEQ_START_TOKEN) {
2138                 seq_puts(seq,
2139                          "  sl  "
2140                          "local_address                         "
2141                          "remote_address                        "
2142                          "st tx_queue rx_queue tr tm->when retrnsmt"
2143                          "   uid  timeout inode\n");
2144                 goto out;
2145         }
2146         st = seq->private;
2147
2148         switch (st->state) {
2149         case TCP_SEQ_STATE_LISTENING:
2150         case TCP_SEQ_STATE_ESTABLISHED:
2151                 get_tcp6_sock(seq, v, st->num);
2152                 break;
2153         case TCP_SEQ_STATE_OPENREQ:
2154                 get_openreq6(seq, st->syn_wait_sk, v, st->num, st->uid);
2155                 break;
2156         case TCP_SEQ_STATE_TIME_WAIT:
2157                 get_timewait6_sock(seq, v, st->num);
2158                 break;
2159         }
2160 out:
2161         return 0;
2162 }
2163
2164 static const struct file_operations tcp6_afinfo_seq_fops = {
2165         .owner   = THIS_MODULE,
2166         .open    = tcp_seq_open,
2167         .read    = seq_read,
2168         .llseek  = seq_lseek,
2169         .release = seq_release_net
2170 };
2171
2172 static struct tcp_seq_afinfo tcp6_seq_afinfo = {
2173         .name           = "tcp6",
2174         .family         = AF_INET6,
2175         .seq_fops       = &tcp6_afinfo_seq_fops,
2176         .seq_ops        = {
2177                 .show           = tcp6_seq_show,
2178         },
2179 };
2180
2181 int __net_init tcp6_proc_init(struct net *net)
2182 {
2183         return tcp_proc_register(net, &tcp6_seq_afinfo);
2184 }
2185
2186 void tcp6_proc_exit(struct net *net)
2187 {
2188         tcp_proc_unregister(net, &tcp6_seq_afinfo);
2189 }
2190 #endif
2191
2192 struct proto tcpv6_prot = {
2193         .name                   = "TCPv6",
2194         .owner                  = THIS_MODULE,
2195         .close                  = tcp_close,
2196         .connect                = tcp_v6_connect,
2197         .disconnect             = tcp_disconnect,
2198         .accept                 = inet_csk_accept,
2199         .ioctl                  = tcp_ioctl,
2200         .init                   = tcp_v6_init_sock,
2201         .destroy                = tcp_v6_destroy_sock,
2202         .shutdown               = tcp_shutdown,
2203         .setsockopt             = tcp_setsockopt,
2204         .getsockopt             = tcp_getsockopt,
2205         .recvmsg                = tcp_recvmsg,
2206         .sendmsg                = tcp_sendmsg,
2207         .sendpage               = tcp_sendpage,
2208         .backlog_rcv            = tcp_v6_do_rcv,
2209         .hash                   = tcp_v6_hash,
2210         .unhash                 = inet_unhash,
2211         .get_port               = inet_csk_get_port,
2212         .enter_memory_pressure  = tcp_enter_memory_pressure,
2213         .sockets_allocated      = &tcp_sockets_allocated,
2214         .memory_allocated       = &tcp_memory_allocated,
2215         .memory_pressure        = &tcp_memory_pressure,
2216         .orphan_count           = &tcp_orphan_count,
2217         .sysctl_mem             = sysctl_tcp_mem,
2218         .sysctl_wmem            = sysctl_tcp_wmem,
2219         .sysctl_rmem            = sysctl_tcp_rmem,
2220         .max_header             = MAX_TCP_HEADER,
2221         .obj_size               = sizeof(struct tcp6_sock),
2222         .slab_flags             = SLAB_DESTROY_BY_RCU,
2223         .twsk_prot              = &tcp6_timewait_sock_ops,
2224         .rsk_prot               = &tcp6_request_sock_ops,
2225         .h.hashinfo             = &tcp_hashinfo,
2226         .no_autobind            = true,
2227 #ifdef CONFIG_COMPAT
2228         .compat_setsockopt      = compat_tcp_setsockopt,
2229         .compat_getsockopt      = compat_tcp_getsockopt,
2230 #endif
2231 };
2232
2233 static const struct inet6_protocol tcpv6_protocol = {
2234         .handler        =       tcp_v6_rcv,
2235         .err_handler    =       tcp_v6_err,
2236         .gso_send_check =       tcp_v6_gso_send_check,
2237         .gso_segment    =       tcp_tso_segment,
2238         .gro_receive    =       tcp6_gro_receive,
2239         .gro_complete   =       tcp6_gro_complete,
2240         .flags          =       INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
2241 };
2242
2243 static struct inet_protosw tcpv6_protosw = {
2244         .type           =       SOCK_STREAM,
2245         .protocol       =       IPPROTO_TCP,
2246         .prot           =       &tcpv6_prot,
2247         .ops            =       &inet6_stream_ops,
2248         .no_check       =       0,
2249         .flags          =       INET_PROTOSW_PERMANENT |
2250                                 INET_PROTOSW_ICSK,
2251 };
2252
2253 static int __net_init tcpv6_net_init(struct net *net)
2254 {
2255         return inet_ctl_sock_create(&net->ipv6.tcp_sk, PF_INET6,
2256                                     SOCK_RAW, IPPROTO_TCP, net);
2257 }
2258
2259 static void __net_exit tcpv6_net_exit(struct net *net)
2260 {
2261         inet_ctl_sock_destroy(net->ipv6.tcp_sk);
2262 }
2263
2264 static void __net_exit tcpv6_net_exit_batch(struct list_head *net_exit_list)
2265 {
2266         inet_twsk_purge(&tcp_hashinfo, &tcp_death_row, AF_INET6);
2267 }
2268
2269 static struct pernet_operations tcpv6_net_ops = {
2270         .init       = tcpv6_net_init,
2271         .exit       = tcpv6_net_exit,
2272         .exit_batch = tcpv6_net_exit_batch,
2273 };
2274
2275 int __init tcpv6_init(void)
2276 {
2277         int ret;
2278
2279         ret = inet6_add_protocol(&tcpv6_protocol, IPPROTO_TCP);
2280         if (ret)
2281                 goto out;
2282
2283         /* register inet6 protocol */
2284         ret = inet6_register_protosw(&tcpv6_protosw);
2285         if (ret)
2286                 goto out_tcpv6_protocol;
2287
2288         ret = register_pernet_subsys(&tcpv6_net_ops);
2289         if (ret)
2290                 goto out_tcpv6_protosw;
2291 out:
2292         return ret;
2293
2294 out_tcpv6_protocol:
2295         inet6_del_protocol(&tcpv6_protocol, IPPROTO_TCP);
2296 out_tcpv6_protosw:
2297         inet6_unregister_protosw(&tcpv6_protosw);
2298         goto out;
2299 }
2300
2301 void tcpv6_exit(void)
2302 {
2303         unregister_pernet_subsys(&tcpv6_net_ops);
2304         inet6_unregister_protosw(&tcpv6_protosw);
2305         inet6_del_protocol(&tcpv6_protocol, IPPROTO_TCP);
2306 }