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
  65 #include <asm/uaccess.h>
  66
  67 #include <linux/proc_fs.h>
  68 #include <linux/seq_file.h>
  69
  70 #include <linux/crypto.h>
  71 #include <linux/scatterlist.h>
  72
  73 static void     tcp_v6_send_reset(struct sock *sk, struct sk_buff *skb);
  74 static void     tcp_v6_reqsk_send_ack(struct sock *sk, struct sk_buff *skb,
  75                                       struct request_sock *req);
  76
  77 static int      tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb);
  78 static void     __tcp_v6_send_check(struct sk_buff *skb,
  79                                     const struct in6_addr *saddr,
  80                                     const struct in6_addr *daddr);
  81
  82 static const struct inet_connection_sock_af_ops ipv6_mapped;
  83 static const struct inet_connection_sock_af_ops ipv6_specific;
  84 #ifdef CONFIG_TCP_MD5SIG
  85 static const struct tcp_sock_af_ops tcp_sock_ipv6_specific;
  86 static const struct tcp_sock_af_ops tcp_sock_ipv6_mapped_specific;
  87 #else
  88 static struct tcp_md5sig_key *tcp_v6_md5_do_lookup(struct sock *sk,
  89                                                    const struct in6_addr *addr)
  90 {
  91         return NULL;
  92 }
  93 #endif
  94
  95 static void tcp_v6_hash(struct sock *sk)
  96 {
  97         if (sk->sk_state != TCP_CLOSE) {
  98                 if (inet_csk(sk)->icsk_af_ops == &ipv6_mapped) {
  99                         tcp_prot.hash(sk);
 100                         return;
 101                 }
 102                 local_bh_disable();
 103                 __inet6_hash(sk, NULL);
 104                 local_bh_enable();
 105         }
 106 }
 107
 108 static __inline__ __sum16 tcp_v6_check(int len,
 109                                    const struct in6_addr *saddr,
 110                                    const struct in6_addr *daddr,
 111                                    __wsum base)
 112 {
 113         return csum_ipv6_magic(saddr, daddr, len, IPPROTO_TCP, base);
 114 }
 115
 116 static __u32 tcp_v6_init_sequence(struct sk_buff *skb)
 117 {
 118         return secure_tcpv6_sequence_number(ipv6_hdr(skb)->daddr.s6_addr32,
 119                                             ipv6_hdr(skb)->saddr.s6_addr32,
 120                                             tcp_hdr(skb)->dest,
 121                                             tcp_hdr(skb)->source);
 122 }
 123
 124 static int tcp_v6_connect(struct sock *sk, struct sockaddr *uaddr,
 125                           int addr_len)
 126 {
 127         struct sockaddr_in6 *usin = (struct sockaddr_in6 *) uaddr;
 128         struct inet_sock *inet = inet_sk(sk);
 129         struct inet_connection_sock *icsk = inet_csk(sk);
 130         struct ipv6_pinfo *np = inet6_sk(sk);
 131         struct tcp_sock *tp = tcp_sk(sk);
 132         struct in6_addr *saddr = NULL, *final_p, final;
 133         struct rt6_info *rt;
 134         struct flowi6 fl6;
 135         struct dst_entry *dst;
 136         int addr_type;
 137         int err;
 138
 139         if (addr_len < SIN6_LEN_RFC2133)
 140                 return -EINVAL;
 141
 142         if (usin->sin6_family != AF_INET6)
 143                 return -EAFNOSUPPORT;
 144
 145         memset(&fl6, 0, sizeof(fl6));
 146
 147         if (np->sndflow) {
 148                 fl6.flowlabel = usin->sin6_flowinfo&IPV6_FLOWINFO_MASK;
 149                 IP6_ECN_flow_init(fl6.flowlabel);
 150                 if (fl6.flowlabel&IPV6_FLOWLABEL_MASK) {
 151                         struct ip6_flowlabel *flowlabel;
 152                         flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
 153                         if (flowlabel == NULL)
 154                                 return -EINVAL;
 155                         ipv6_addr_copy(&usin->sin6_addr, &flowlabel->dst);
 156                         fl6_sock_release(flowlabel);
 157                 }
 158         }
 159
 160         /*
 161          *      connect() to INADDR_ANY means loopback (BSD'ism).
 162          */
 163
 164         if(ipv6_addr_any(&usin->sin6_addr))
 165                 usin->sin6_addr.s6_addr[15] = 0x1;
 166
 167         addr_type = ipv6_addr_type(&usin->sin6_addr);
 168
 169         if(addr_type & IPV6_ADDR_MULTICAST)
 170                 return -ENETUNREACH;
 171
 172         if (addr_type&IPV6_ADDR_LINKLOCAL) {
 173                 if (addr_len >= sizeof(struct sockaddr_in6) &&
 174                     usin->sin6_scope_id) {
 175                         /* If interface is set while binding, indices
 176                          * must coincide.
 177                          */
 178                         if (sk->sk_bound_dev_if &&
 179                             sk->sk_bound_dev_if != usin->sin6_scope_id)
 180                                 return -EINVAL;
 181
 182                         sk->sk_bound_dev_if = usin->sin6_scope_id;
 183                 }
 184
 185                 /* Connect to link-local address requires an interface */
 186                 if (!sk->sk_bound_dev_if)
 187                         return -EINVAL;
 188         }
 189
 190         if (tp->rx_opt.ts_recent_stamp &&
 191             !ipv6_addr_equal(&np->daddr, &usin->sin6_addr)) {
 192                 tp->rx_opt.ts_recent = 0;
 193                 tp->rx_opt.ts_recent_stamp = 0;
 194                 tp->write_seq = 0;
 195         }
 196
 197         ipv6_addr_copy(&np->daddr, &usin->sin6_addr);
 198         np->flow_label = fl6.flowlabel;
 199
 200         /*
 201          *      TCP over IPv4
 202          */
 203
 204         if (addr_type == IPV6_ADDR_MAPPED) {
 205                 u32 exthdrlen = icsk->icsk_ext_hdr_len;
 206                 struct sockaddr_in sin;
 207
 208                 SOCK_DEBUG(sk, "connect: ipv4 mapped\n");
 209
 210                 if (__ipv6_only_sock(sk))
 211                         return -ENETUNREACH;
 212
 213                 sin.sin_family = AF_INET;
 214                 sin.sin_port = usin->sin6_port;
 215                 sin.sin_addr.s_addr = usin->sin6_addr.s6_addr32[3];
 216
 217                 icsk->icsk_af_ops = &ipv6_mapped;
 218                 sk->sk_backlog_rcv = tcp_v4_do_rcv;
 219 #ifdef CONFIG_TCP_MD5SIG
 220                 tp->af_specific = &tcp_sock_ipv6_mapped_specific;
 221 #endif
 222
 223                 err = tcp_v4_connect(sk, (struct sockaddr *)&sin, sizeof(sin));
 224
 225                 if (err) {
 226                         icsk->icsk_ext_hdr_len = exthdrlen;
 227                         icsk->icsk_af_ops = &ipv6_specific;
 228                         sk->sk_backlog_rcv = tcp_v6_do_rcv;
 229 #ifdef CONFIG_TCP_MD5SIG
 230                         tp->af_specific = &tcp_sock_ipv6_specific;
 231 #endif
 232                         goto failure;
 233                 } else {
 234                         ipv6_addr_set_v4mapped(inet->inet_saddr, &np->saddr);
 235                         ipv6_addr_set_v4mapped(inet->inet_rcv_saddr,
 236                                                &np->rcv_saddr);
 237                 }
 238
 239                 return err;
 240         }
 241
 242         if (!ipv6_addr_any(&np->rcv_saddr))
 243                 saddr = &np->rcv_saddr;
 244
 245         fl6.flowi6_proto = IPPROTO_TCP;
 246         ipv6_addr_copy(&fl6.daddr, &np->daddr);
 247         ipv6_addr_copy(&fl6.saddr,
 248                        (saddr ? saddr : &np->saddr));
 249         fl6.flowi6_oif = sk->sk_bound_dev_if;
 250         fl6.flowi6_mark = sk->sk_mark;
 251         fl6.fl6_dport = usin->sin6_port;
 252         fl6.fl6_sport = inet->inet_sport;
 253
 254         final_p = fl6_update_dst(&fl6, np->opt, &final);
 255
 256         security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));
 257
 258         dst = ip6_dst_lookup_flow(sk, &fl6, final_p, true);
 259         if (IS_ERR(dst)) {
 260                 err = PTR_ERR(dst);
 261                 goto failure;
 262         }
 263
 264         if (saddr == NULL) {
 265                 saddr = &fl6.saddr;
 266                 ipv6_addr_copy(&np->rcv_saddr, saddr);
 267         }
 268
 269         /* set the source address */
 270         ipv6_addr_copy(&np->saddr, saddr);
 271         inet->inet_rcv_saddr = LOOPBACK4_IPV6;
 272
 273         sk->sk_gso_type = SKB_GSO_TCPV6;
 274         __ip6_dst_store(sk, dst, NULL, NULL);
 275
 276         rt = (struct rt6_info *) dst;
 277         if (tcp_death_row.sysctl_tw_recycle &&
 278             !tp->rx_opt.ts_recent_stamp &&
 279             ipv6_addr_equal(&rt->rt6i_dst.addr, &np->daddr)) {
 280                 struct inet_peer *peer = rt6_get_peer(rt);
 281                 /*
 282                  * VJ's idea. We save last timestamp seen from
 283                  * the destination in peer table, when entering state
 284                  * TIME-WAIT * and initialize rx_opt.ts_recent from it,
 285                  * when trying new connection.
 286                  */
 287                 if (peer) {
 288                         inet_peer_refcheck(peer);
 289                         if ((u32)get_seconds() - peer->tcp_ts_stamp <= TCP_PAWS_MSL) {
 290                                 tp->rx_opt.ts_recent_stamp = peer->tcp_ts_stamp;
 291                                 tp->rx_opt.ts_recent = peer->tcp_ts;
 292                         }
 293                 }
 294         }
 295
 296         icsk->icsk_ext_hdr_len = 0;
 297         if (np->opt)
 298                 icsk->icsk_ext_hdr_len = (np->opt->opt_flen +
 299                                           np->opt->opt_nflen);
 300
 301         tp->rx_opt.mss_clamp = IPV6_MIN_MTU - sizeof(struct tcphdr) - sizeof(struct ipv6hdr);
 302
 303         inet->inet_dport = usin->sin6_port;
 304
 305         tcp_set_state(sk, TCP_SYN_SENT);
 306         err = inet6_hash_connect(&tcp_death_row, sk);
 307         if (err)
 308                 goto late_failure;
 309
 310         if (!tp->write_seq)
 311                 tp->write_seq = secure_tcpv6_sequence_number(np->saddr.s6_addr32,
 312                                                              np->daddr.s6_addr32,
 313                                                              inet->inet_sport,
 314                                                              inet->inet_dport);
 315
 316         err = tcp_connect(sk);
 317         if (err)
 318                 goto late_failure;
 319
 320         return 0;
 321
 322 late_failure:
 323         tcp_set_state(sk, TCP_CLOSE);
 324         __sk_dst_reset(sk);
 325 failure:
 326         inet->inet_dport = 0;
 327         sk->sk_route_caps = 0;
 328         return err;
 329 }
 330
 331 static void tcp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 332                 u8 type, u8 code, int offset, __be32 info)
 333 {
 334         const struct ipv6hdr *hdr = (const struct ipv6hdr*)skb->data;
 335         const struct tcphdr *th = (struct tcphdr *)(skb->data+offset);
 336         struct ipv6_pinfo *np;
 337         struct sock *sk;
 338         int err;
 339         struct tcp_sock *tp;
 340         __u32 seq;
 341         struct net *net = dev_net(skb->dev);
 342
 343         sk = inet6_lookup(net, &tcp_hashinfo, &hdr->daddr,
 344                         th->dest, &hdr->saddr, th->source, skb->dev->ifindex);
 345
 346         if (sk == NULL) {
 347                 ICMP6_INC_STATS_BH(net, __in6_dev_get(skb->dev),
 348                                    ICMP6_MIB_INERRORS);
 349                 return;
 350         }
 351
 352         if (sk->sk_state == TCP_TIME_WAIT) {
 353                 inet_twsk_put(inet_twsk(sk));
 354                 return;
 355         }
 356
 357         bh_lock_sock(sk);
 358         if (sock_owned_by_user(sk))
 359                 NET_INC_STATS_BH(net, LINUX_MIB_LOCKDROPPEDICMPS);
 360
 361         if (sk->sk_state == TCP_CLOSE)
 362                 goto out;
 363
 364         if (ipv6_hdr(skb)->hop_limit < inet6_sk(sk)->min_hopcount) {
 365                 NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP);
 366                 goto out;
 367         }
 368
 369         tp = tcp_sk(sk);
 370         seq = ntohl(th->seq);
 371         if (sk->sk_state != TCP_LISTEN &&
 372             !between(seq, tp->snd_una, tp->snd_nxt)) {
 373                 NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
 374                 goto out;
 375         }
 376
 377         np = inet6_sk(sk);
 378
 379         if (type == ICMPV6_PKT_TOOBIG) {
 380                 struct dst_entry *dst;
 381
 382                 if (sock_owned_by_user(sk))
 383                         goto out;
 384                 if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE))
 385                         goto out;
 386
 387                 /* icmp should have updated the destination cache entry */
 388                 dst = __sk_dst_check(sk, np->dst_cookie);
 389
 390                 if (dst == NULL) {
 391                         struct inet_sock *inet = inet_sk(sk);
 392                         struct flowi6 fl6;
 393
 394                         /* BUGGG_FUTURE: Again, it is not clear how
 395                            to handle rthdr case. Ignore this complexity
 396                            for now.
 397                          */
 398                         memset(&fl6, 0, sizeof(fl6));
 399                         fl6.flowi6_proto = IPPROTO_TCP;
 400                         ipv6_addr_copy(&fl6.daddr, &np->daddr);
 401                         ipv6_addr_copy(&fl6.saddr, &np->saddr);
 402                         fl6.flowi6_oif = sk->sk_bound_dev_if;
 403                         fl6.flowi6_mark = sk->sk_mark;
 404                         fl6.fl6_dport = inet->inet_dport;
 405                         fl6.fl6_sport = inet->inet_sport;
 406                         security_skb_classify_flow(skb, flowi6_to_flowi(&fl6));
 407
 408                         dst = ip6_dst_lookup_flow(sk, &fl6, NULL, false);
 409                         if (IS_ERR(dst)) {
 410                                 sk->sk_err_soft = -PTR_ERR(dst);
 411                                 goto out;
 412                         }
 413
 414                 } else
 415                         dst_hold(dst);
 416
 417                 if (inet_csk(sk)->icsk_pmtu_cookie > dst_mtu(dst)) {
 418                         tcp_sync_mss(sk, dst_mtu(dst));
 419                         tcp_simple_retransmit(sk);
 420                 } /* else let the usual retransmit timer handle it */
 421                 dst_release(dst);
 422                 goto out;
 423         }
 424
 425         icmpv6_err_convert(type, code, &err);
 426
 427         /* Might be for an request_sock */
 428         switch (sk->sk_state) {
 429                 struct request_sock *req, **prev;
 430         case TCP_LISTEN:
 431                 if (sock_owned_by_user(sk))
 432                         goto out;
 433
 434                 req = inet6_csk_search_req(sk, &prev, th->dest, &hdr->daddr,
 435                                            &hdr->saddr, inet6_iif(skb));
 436                 if (!req)
 437                         goto out;
 438
 439                 /* ICMPs are not backlogged, hence we cannot get
 440                  * an established socket here.
 441                  */
 442                 WARN_ON(req->sk != NULL);
 443
 444                 if (seq != tcp_rsk(req)->snt_isn) {
 445                         NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
 446                         goto out;
 447                 }
 448
 449                 inet_csk_reqsk_queue_drop(sk, req, prev);
 450                 goto out;
 451
 452         case TCP_SYN_SENT:
 453         case TCP_SYN_RECV:  /* Cannot happen.
 454                                It can, it SYNs are crossed. --ANK */
 455                 if (!sock_owned_by_user(sk)) {
 456                         sk->sk_err = err;
 457                         sk->sk_error_report(sk);                /* Wake people up to see the error (see connect in sock.c) */
 458
 459                         tcp_done(sk);
 460                 } else
 461                         sk->sk_err_soft = err;
 462                 goto out;
 463         }
 464
 465         if (!sock_owned_by_user(sk) && np->recverr) {
 466                 sk->sk_err = err;
 467                 sk->sk_error_report(sk);
 468         } else
 469                 sk->sk_err_soft = err;
 470
 471 out:
 472         bh_unlock_sock(sk);
 473         sock_put(sk);
 474 }
 475
 476
 477 static int tcp_v6_send_synack(struct sock *sk, struct request_sock *req,
 478                               struct request_values *rvp)
 479 {
 480         struct inet6_request_sock *treq = inet6_rsk(req);
 481         struct ipv6_pinfo *np = inet6_sk(sk);
 482         struct sk_buff * skb;
 483         struct ipv6_txoptions *opt = NULL;
 484         struct in6_addr * final_p, final;
 485         struct flowi6 fl6;
 486         struct dst_entry *dst;
 487         int err;
 488
 489         memset(&fl6, 0, sizeof(fl6));
 490         fl6.flowi6_proto = IPPROTO_TCP;
 491         ipv6_addr_copy(&fl6.daddr, &treq->rmt_addr);
 492         ipv6_addr_copy(&fl6.saddr, &treq->loc_addr);
 493         fl6.flowlabel = 0;
 494         fl6.flowi6_oif = treq->iif;
 495         fl6.flowi6_mark = sk->sk_mark;
 496         fl6.fl6_dport = inet_rsk(req)->rmt_port;
 497         fl6.fl6_sport = inet_rsk(req)->loc_port;
 498         security_req_classify_flow(req, flowi6_to_flowi(&fl6));
 499
 500         opt = np->opt;
 501         final_p = fl6_update_dst(&fl6, opt, &final);
 502
 503         dst = ip6_dst_lookup_flow(sk, &fl6, final_p, false);
 504         if (IS_ERR(dst)) {
 505                 err = PTR_ERR(dst);
 506                 dst = NULL;
 507                 goto done;
 508         }
 509         skb = tcp_make_synack(sk, dst, req, rvp);
 510         err = -ENOMEM;
 511         if (skb) {
 512                 __tcp_v6_send_check(skb, &treq->loc_addr, &treq->rmt_addr);
 513
 514                 ipv6_addr_copy(&fl6.daddr, &treq->rmt_addr);
 515                 err = ip6_xmit(sk, skb, &fl6, opt);
 516                 err = net_xmit_eval(err);
 517         }
 518
 519 done:
 520         if (opt && opt != np->opt)
 521                 sock_kfree_s(sk, opt, opt->tot_len);
 522         dst_release(dst);
 523         return err;
 524 }
 525
 526 static int tcp_v6_rtx_synack(struct sock *sk, struct request_sock *req,
 527                              struct request_values *rvp)
 528 {
 529         TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_RETRANSSEGS);
 530         return tcp_v6_send_synack(sk, req, rvp);
 531 }
 532
 533 static inline void syn_flood_warning(struct sk_buff *skb)
 534 {
 535 #ifdef CONFIG_SYN_COOKIES
 536         if (sysctl_tcp_syncookies)
 537                 printk(KERN_INFO
 538                        "TCPv6: Possible SYN flooding on port %d. "
 539                        "Sending cookies.\n", ntohs(tcp_hdr(skb)->dest));
 540         else
 541 #endif
 542                 printk(KERN_INFO
 543                        "TCPv6: Possible SYN flooding on port %d. "
 544                        "Dropping request.\n", ntohs(tcp_hdr(skb)->dest));
 545 }
 546
 547 static void tcp_v6_reqsk_destructor(struct request_sock *req)
 548 {
 549         kfree_skb(inet6_rsk(req)->pktopts);
 550 }
 551
 552 #ifdef CONFIG_TCP_MD5SIG
 553 static struct tcp_md5sig_key *tcp_v6_md5_do_lookup(struct sock *sk,
 554                                                    const struct in6_addr *addr)
 555 {
 556         struct tcp_sock *tp = tcp_sk(sk);
 557         int i;
 558
 559         BUG_ON(tp == NULL);
 560
 561         if (!tp->md5sig_info || !tp->md5sig_info->entries6)
 562                 return NULL;
 563
 564         for (i = 0; i < tp->md5sig_info->entries6; i++) {
 565                 if (ipv6_addr_equal(&tp->md5sig_info->keys6[i].addr, addr))
 566                         return &tp->md5sig_info->keys6[i].base;
 567         }
 568         return NULL;
 569 }
 570
 571 static struct tcp_md5sig_key *tcp_v6_md5_lookup(struct sock *sk,
 572                                                 struct sock *addr_sk)
 573 {
 574         return tcp_v6_md5_do_lookup(sk, &inet6_sk(addr_sk)->daddr);
 575 }
 576
 577 static struct tcp_md5sig_key *tcp_v6_reqsk_md5_lookup(struct sock *sk,
 578                                                       struct request_sock *req)
 579 {
 580         return tcp_v6_md5_do_lookup(sk, &inet6_rsk(req)->rmt_addr);
 581 }
 582
 583 static int tcp_v6_md5_do_add(struct sock *sk, const struct in6_addr *peer,
 584                              char *newkey, u8 newkeylen)
 585 {
 586         /* Add key to the list */
 587         struct tcp_md5sig_key *key;
 588         struct tcp_sock *tp = tcp_sk(sk);
 589         struct tcp6_md5sig_key *keys;
 590
 591         key = tcp_v6_md5_do_lookup(sk, peer);
 592         if (key) {
 593                 /* modify existing entry - just update that one */
 594                 kfree(key->key);
 595                 key->key = newkey;
 596                 key->keylen = newkeylen;
 597         } else {
 598                 /* reallocate new list if current one is full. */
 599                 if (!tp->md5sig_info) {
 600                         tp->md5sig_info = kzalloc(sizeof(*tp->md5sig_info), GFP_ATOMIC);
 601                         if (!tp->md5sig_info) {
 602                                 kfree(newkey);
 603                                 return -ENOMEM;
 604                         }
 605                         sk_nocaps_add(sk, NETIF_F_GSO_MASK);
 606                 }
 607                 if (tcp_alloc_md5sig_pool(sk) == NULL) {
 608                         kfree(newkey);
 609                         return -ENOMEM;
 610                 }
 611                 if (tp->md5sig_info->alloced6 == tp->md5sig_info->entries6) {
 612                         keys = kmalloc((sizeof (tp->md5sig_info->keys6[0]) *
 613                                        (tp->md5sig_info->entries6 + 1)), GFP_ATOMIC);
 614
 615                         if (!keys) {
 616                                 tcp_free_md5sig_pool();
 617                                 kfree(newkey);
 618                                 return -ENOMEM;
 619                         }
 620
 621                         if (tp->md5sig_info->entries6)
 622                                 memmove(keys, tp->md5sig_info->keys6,
 623                                         (sizeof (tp->md5sig_info->keys6[0]) *
 624                                          tp->md5sig_info->entries6));
 625
 626                         kfree(tp->md5sig_info->keys6);
 627                         tp->md5sig_info->keys6 = keys;
 628                         tp->md5sig_info->alloced6++;
 629                 }
 630
 631                 ipv6_addr_copy(&tp->md5sig_info->keys6[tp->md5sig_info->entries6].addr,
 632                                peer);
 633                 tp->md5sig_info->keys6[tp->md5sig_info->entries6].base.key = newkey;
 634                 tp->md5sig_info->keys6[tp->md5sig_info->entries6].base.keylen = newkeylen;
 635
 636                 tp->md5sig_info->entries6++;
 637         }
 638         return 0;
 639 }
 640
 641 static int tcp_v6_md5_add_func(struct sock *sk, struct sock *addr_sk,
 642                                u8 *newkey, __u8 newkeylen)
 643 {
 644         return tcp_v6_md5_do_add(sk, &inet6_sk(addr_sk)->daddr,
 645                                  newkey, newkeylen);
 646 }
 647
 648 static int tcp_v6_md5_do_del(struct sock *sk, const struct in6_addr *peer)
 649 {
 650         struct tcp_sock *tp = tcp_sk(sk);
 651         int i;
 652
 653         for (i = 0; i < tp->md5sig_info->entries6; i++) {
 654                 if (ipv6_addr_equal(&tp->md5sig_info->keys6[i].addr, peer)) {
 655                         /* Free the key */
 656                         kfree(tp->md5sig_info->keys6[i].base.key);
 657                         tp->md5sig_info->entries6--;
 658
 659                         if (tp->md5sig_info->entries6 == 0) {
 660                                 kfree(tp->md5sig_info->keys6);
 661                                 tp->md5sig_info->keys6 = NULL;
 662                                 tp->md5sig_info->alloced6 = 0;
 663                         } else {
 664                                 /* shrink the database */
 665                                 if (tp->md5sig_info->entries6 != i)
 666                                         memmove(&tp->md5sig_info->keys6[i],
 667                                                 &tp->md5sig_info->keys6[i+1],
 668                                                 (tp->md5sig_info->entries6 - i)
 669                                                 * sizeof (tp->md5sig_info->keys6[0]));
 670                         }
 671                         tcp_free_md5sig_pool();
 672                         return 0;
 673                 }
 674         }
 675         return -ENOENT;
 676 }
 677
 678 static void tcp_v6_clear_md5_list (struct sock *sk)
 679 {
 680         struct tcp_sock *tp = tcp_sk(sk);
 681         int i;
 682
 683         if (tp->md5sig_info->entries6) {
 684                 for (i = 0; i < tp->md5sig_info->entries6; i++)
 685                         kfree(tp->md5sig_info->keys6[i].base.key);
 686                 tp->md5sig_info->entries6 = 0;
 687                 tcp_free_md5sig_pool();
 688         }
 689
 690         kfree(tp->md5sig_info->keys6);
 691         tp->md5sig_info->keys6 = NULL;
 692         tp->md5sig_info->alloced6 = 0;
 693
 694         if (tp->md5sig_info->entries4) {
 695                 for (i = 0; i < tp->md5sig_info->entries4; i++)
 696                         kfree(tp->md5sig_info->keys4[i].base.key);
 697                 tp->md5sig_info->entries4 = 0;
 698                 tcp_free_md5sig_pool();
 699         }
 700
 701         kfree(tp->md5sig_info->keys4);
 702         tp->md5sig_info->keys4 = NULL;
 703         tp->md5sig_info->alloced4 = 0;
 704 }
 705
 706 static int tcp_v6_parse_md5_keys (struct sock *sk, char __user *optval,
 707                                   int optlen)
 708 {
 709         struct tcp_md5sig cmd;
 710         struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)&cmd.tcpm_addr;
 711         u8 *newkey;
 712
 713         if (optlen < sizeof(cmd))
 714                 return -EINVAL;
 715
 716         if (copy_from_user(&cmd, optval, sizeof(cmd)))
 717                 return -EFAULT;
 718
 719         if (sin6->sin6_family != AF_INET6)
 720                 return -EINVAL;
 721
 722         if (!cmd.tcpm_keylen) {
 723                 if (!tcp_sk(sk)->md5sig_info)
 724                         return -ENOENT;
 725                 if (ipv6_addr_v4mapped(&sin6->sin6_addr))
 726                         return tcp_v4_md5_do_del(sk, sin6->sin6_addr.s6_addr32[3]);
 727                 return tcp_v6_md5_do_del(sk, &sin6->sin6_addr);
 728         }
 729
 730         if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN)
 731                 return -EINVAL;
 732
 733         if (!tcp_sk(sk)->md5sig_info) {
 734                 struct tcp_sock *tp = tcp_sk(sk);
 735                 struct tcp_md5sig_info *p;
 736
 737                 p = kzalloc(sizeof(struct tcp_md5sig_info), GFP_KERNEL);
 738                 if (!p)
 739                         return -ENOMEM;
 740
 741                 tp->md5sig_info = p;
 742                 sk_nocaps_add(sk, NETIF_F_GSO_MASK);
 743         }
 744
 745         newkey = kmemdup(cmd.tcpm_key, cmd.tcpm_keylen, GFP_KERNEL);
 746         if (!newkey)
 747                 return -ENOMEM;
 748         if (ipv6_addr_v4mapped(&sin6->sin6_addr)) {
 749                 return tcp_v4_md5_do_add(sk, sin6->sin6_addr.s6_addr32[3],
 750                                          newkey, cmd.tcpm_keylen);
 751         }
 752         return tcp_v6_md5_do_add(sk, &sin6->sin6_addr, newkey, cmd.tcpm_keylen);
 753 }
 754
 755 static int tcp_v6_md5_hash_pseudoheader(struct tcp_md5sig_pool *hp,
 756                                         const struct in6_addr *daddr,
 757                                         const struct in6_addr *saddr, int nbytes)
 758 {
 759         struct tcp6_pseudohdr *bp;
 760         struct scatterlist sg;
 761
 762         bp = &hp->md5_blk.ip6;
 763         /* 1. TCP pseudo-header (RFC2460) */
 764         ipv6_addr_copy(&bp->saddr, saddr);
 765         ipv6_addr_copy(&bp->daddr, daddr);
 766         bp->protocol = cpu_to_be32(IPPROTO_TCP);
 767         bp->len = cpu_to_be32(nbytes);
 768
 769         sg_init_one(&sg, bp, sizeof(*bp));
 770         return crypto_hash_update(&hp->md5_desc, &sg, sizeof(*bp));
 771 }
 772
 773 static int tcp_v6_md5_hash_hdr(char *md5_hash, struct tcp_md5sig_key *key,
 774                                const struct in6_addr *daddr, struct in6_addr *saddr,
 775                                struct tcphdr *th)
 776 {
 777         struct tcp_md5sig_pool *hp;
 778         struct hash_desc *desc;
 779
 780         hp = tcp_get_md5sig_pool();
 781         if (!hp)
 782                 goto clear_hash_noput;
 783         desc = &hp->md5_desc;
 784
 785         if (crypto_hash_init(desc))
 786                 goto clear_hash;
 787         if (tcp_v6_md5_hash_pseudoheader(hp, daddr, saddr, th->doff << 2))
 788                 goto clear_hash;
 789         if (tcp_md5_hash_header(hp, th))
 790                 goto clear_hash;
 791         if (tcp_md5_hash_key(hp, key))
 792                 goto clear_hash;
 793         if (crypto_hash_final(desc, md5_hash))
 794                 goto clear_hash;
 795
 796         tcp_put_md5sig_pool();
 797         return 0;
 798
 799 clear_hash:
 800         tcp_put_md5sig_pool();
 801 clear_hash_noput:
 802         memset(md5_hash, 0, 16);
 803         return 1;
 804 }
 805
 806 static int tcp_v6_md5_hash_skb(char *md5_hash, struct tcp_md5sig_key *key,
 807                                struct sock *sk, struct request_sock *req,
 808                                struct sk_buff *skb)
 809 {
 810         const struct in6_addr *saddr, *daddr;
 811         struct tcp_md5sig_pool *hp;
 812         struct hash_desc *desc;
 813         struct tcphdr *th = tcp_hdr(skb);
 814
 815         if (sk) {
 816                 saddr = &inet6_sk(sk)->saddr;
 817                 daddr = &inet6_sk(sk)->daddr;
 818         } else if (req) {
 819                 saddr = &inet6_rsk(req)->loc_addr;
 820                 daddr = &inet6_rsk(req)->rmt_addr;
 821         } else {
 822                 const struct ipv6hdr *ip6h = ipv6_hdr(skb);
 823                 saddr = &ip6h->saddr;
 824                 daddr = &ip6h->daddr;
 825         }
 826
 827         hp = tcp_get_md5sig_pool();
 828         if (!hp)
 829                 goto clear_hash_noput;
 830         desc = &hp->md5_desc;
 831
 832         if (crypto_hash_init(desc))
 833                 goto clear_hash;
 834
 835         if (tcp_v6_md5_hash_pseudoheader(hp, daddr, saddr, skb->len))
 836                 goto clear_hash;
 837         if (tcp_md5_hash_header(hp, th))
 838                 goto clear_hash;
 839         if (tcp_md5_hash_skb_data(hp, skb, th->doff << 2))
 840                 goto clear_hash;
 841         if (tcp_md5_hash_key(hp, key))
 842                 goto clear_hash;
 843         if (crypto_hash_final(desc, md5_hash))
 844                 goto clear_hash;
 845
 846         tcp_put_md5sig_pool();
 847         return 0;
 848
 849 clear_hash:
 850         tcp_put_md5sig_pool();
 851 clear_hash_noput:
 852         memset(md5_hash, 0, 16);
 853         return 1;
 854 }
 855
 856 static int tcp_v6_inbound_md5_hash (struct sock *sk, struct sk_buff *skb)
 857 {
 858         __u8 *hash_location = NULL;
 859         struct tcp_md5sig_key *hash_expected;
 860         const struct ipv6hdr *ip6h = ipv6_hdr(skb);
 861         struct tcphdr *th = tcp_hdr(skb);
 862         int genhash;
 863         u8 newhash[16];
 864
 865         hash_expected = tcp_v6_md5_do_lookup(sk, &ip6h->saddr);
 866         hash_location = tcp_parse_md5sig_option(th);
 867
 868         /* We've parsed the options - do we have a hash? */
 869         if (!hash_expected && !hash_location)
 870                 return 0;
 871
 872         if (hash_expected && !hash_location) {
 873                 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5NOTFOUND);
 874                 return 1;
 875         }
 876
 877         if (!hash_expected && hash_location) {
 878                 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5UNEXPECTED);
 879                 return 1;
 880         }
 881
 882         /* check the signature */
 883         genhash = tcp_v6_md5_hash_skb(newhash,
 884                                       hash_expected,
 885                                       NULL, NULL, skb);
 886
 887         if (genhash || memcmp(hash_location, newhash, 16) != 0) {
 888                 if (net_ratelimit()) {
 889                         printk(KERN_INFO "MD5 Hash %s for [%pI6c]:%u->[%pI6c]:%u\n",
 890                                genhash ? "failed" : "mismatch",
 891                                &ip6h->saddr, ntohs(th->source),
 892                                &ip6h->daddr, ntohs(th->dest));
 893                 }
 894                 return 1;
 895         }
 896         return 0;
 897 }
 898 #endif
 899
 900 struct request_sock_ops tcp6_request_sock_ops __read_mostly = {
 901         .family         =       AF_INET6,
 902         .obj_size       =       sizeof(struct tcp6_request_sock),
 903         .rtx_syn_ack    =       tcp_v6_rtx_synack,
 904         .send_ack       =       tcp_v6_reqsk_send_ack,
 905         .destructor     =       tcp_v6_reqsk_destructor,
 906         .send_reset     =       tcp_v6_send_reset,
 907         .syn_ack_timeout =      tcp_syn_ack_timeout,
 908 };
 909
 910 #ifdef CONFIG_TCP_MD5SIG
 911 static const struct tcp_request_sock_ops tcp_request_sock_ipv6_ops = {
 912         .md5_lookup     =       tcp_v6_reqsk_md5_lookup,
 913         .calc_md5_hash  =       tcp_v6_md5_hash_skb,
 914 };
 915 #endif
 916
 917 static void __tcp_v6_send_check(struct sk_buff *skb,
 918                                 const struct in6_addr *saddr, const struct in6_addr *daddr)
 919 {
 920         struct tcphdr *th = tcp_hdr(skb);
 921
 922         if (skb->ip_summed == CHECKSUM_PARTIAL) {
 923                 th->check = ~tcp_v6_check(skb->len, saddr, daddr, 0);
 924                 skb->csum_start = skb_transport_header(skb) - skb->head;
 925                 skb->csum_offset = offsetof(struct tcphdr, check);
 926         } else {
 927                 th->check = tcp_v6_check(skb->len, saddr, daddr,
 928                                          csum_partial(th, th->doff << 2,
 929                                                       skb->csum));
 930         }
 931 }
 932
 933 static void tcp_v6_send_check(struct sock *sk, struct sk_buff *skb)
 934 {
 935         struct ipv6_pinfo *np = inet6_sk(sk);
 936
 937         __tcp_v6_send_check(skb, &np->saddr, &np->daddr);
 938 }
 939
 940 static int tcp_v6_gso_send_check(struct sk_buff *skb)
 941 {
 942         const struct ipv6hdr *ipv6h;
 943         struct tcphdr *th;
 944
 945         if (!pskb_may_pull(skb, sizeof(*th)))
 946                 return -EINVAL;
 947
 948         ipv6h = ipv6_hdr(skb);
 949         th = tcp_hdr(skb);
 950
 951         th->check = 0;
 952         skb->ip_summed = CHECKSUM_PARTIAL;
 953         __tcp_v6_send_check(skb, &ipv6h->saddr, &ipv6h->daddr);
 954         return 0;
 955 }
 956
 957 static struct sk_buff **tcp6_gro_receive(struct sk_buff **head,
 958                                          struct sk_buff *skb)
 959 {
 960         const struct ipv6hdr *iph = skb_gro_network_header(skb);
 961
 962         switch (skb->ip_summed) {
 963         case CHECKSUM_COMPLETE:
 964                 if (!tcp_v6_check(skb_gro_len(skb), &iph->saddr, &iph->daddr,
 965                                   skb->csum)) {
 966                         skb->ip_summed = CHECKSUM_UNNECESSARY;
 967                         break;
 968                 }
 969
 970                 /* fall through */
 971         case CHECKSUM_NONE:
 972                 NAPI_GRO_CB(skb)->flush = 1;
 973                 return NULL;
 974         }
 975
 976         return tcp_gro_receive(head, skb);
 977 }
 978
 979 static int tcp6_gro_complete(struct sk_buff *skb)
 980 {
 981         const struct ipv6hdr *iph = ipv6_hdr(skb);
 982         struct tcphdr *th = tcp_hdr(skb);
 983
 984         th->check = ~tcp_v6_check(skb->len - skb_transport_offset(skb),
 985                                   &iph->saddr, &iph->daddr, 0);
 986         skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
 987
 988         return tcp_gro_complete(skb);
 989 }
 990
 991 static void tcp_v6_send_response(struct sk_buff *skb, u32 seq, u32 ack, u32 win,
 992                                  u32 ts, struct tcp_md5sig_key *key, int rst)
 993 {
 994         struct tcphdr *th = tcp_hdr(skb), *t1;
 995         struct sk_buff *buff;
 996         struct flowi6 fl6;
 997         struct net *net = dev_net(skb_dst(skb)->dev);
 998         struct sock *ctl_sk = net->ipv6.tcp_sk;
 999         unsigned int tot_len = sizeof(struct tcphdr);
1000         struct dst_entry *dst;
1001         __be32 *topt;
1002
1003         if (ts)
1004                 tot_len += TCPOLEN_TSTAMP_ALIGNED;
1005 #ifdef CONFIG_TCP_MD5SIG
1006         if (key)
1007                 tot_len += TCPOLEN_MD5SIG_ALIGNED;
1008 #endif
1009
1010         buff = alloc_skb(MAX_HEADER + sizeof(struct ipv6hdr) + tot_len,
1011                          GFP_ATOMIC);
1012         if (buff == NULL)
1013                 return;
1014
1015         skb_reserve(buff, MAX_HEADER + sizeof(struct ipv6hdr) + tot_len);
1016
1017         t1 = (struct tcphdr *) skb_push(buff, tot_len);
1018         skb_reset_transport_header(buff);
1019
1020         /* Swap the send and the receive. */
1021         memset(t1, 0, sizeof(*t1));
1022         t1->dest = th->source;
1023         t1->source = th->dest;
1024         t1->doff = tot_len / 4;
1025         t1->seq = htonl(seq);
1026         t1->ack_seq = htonl(ack);
1027         t1->ack = !rst || !th->ack;
1028         t1->rst = rst;
1029         t1->window = htons(win);
1030
1031         topt = (__be32 *)(t1 + 1);
1032
1033         if (ts) {
1034                 *topt++ = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
1035                                 (TCPOPT_TIMESTAMP << 8) | TCPOLEN_TIMESTAMP);
1036                 *topt++ = htonl(tcp_time_stamp);
1037                 *topt++ = htonl(ts);
1038         }
1039
1040 #ifdef CONFIG_TCP_MD5SIG
1041         if (key) {
1042                 *topt++ = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
1043                                 (TCPOPT_MD5SIG << 8) | TCPOLEN_MD5SIG);
1044                 tcp_v6_md5_hash_hdr((__u8 *)topt, key,
1045                                     &ipv6_hdr(skb)->saddr,
1046                                     &ipv6_hdr(skb)->daddr, t1);
1047         }
1048 #endif
1049
1050         memset(&fl6, 0, sizeof(fl6));
1051         ipv6_addr_copy(&fl6.daddr, &ipv6_hdr(skb)->saddr);
1052         ipv6_addr_copy(&fl6.saddr, &ipv6_hdr(skb)->daddr);
1053
1054         buff->ip_summed = CHECKSUM_PARTIAL;
1055         buff->csum = 0;
1056
1057         __tcp_v6_send_check(buff, &fl6.saddr, &fl6.daddr);
1058
1059         fl6.flowi6_proto = IPPROTO_TCP;
1060         fl6.flowi6_oif = inet6_iif(skb);
1061         fl6.fl6_dport = t1->dest;
1062         fl6.fl6_sport = t1->source;
1063         security_skb_classify_flow(skb, flowi6_to_flowi(&fl6));
1064
1065         /* Pass a socket to ip6_dst_lookup either it is for RST
1066          * Underlying function will use this to retrieve the network
1067          * namespace
1068          */
1069         dst = ip6_dst_lookup_flow(ctl_sk, &fl6, NULL, false);
1070         if (!IS_ERR(dst)) {
1071                 skb_dst_set(buff, dst);
1072                 ip6_xmit(ctl_sk, buff, &fl6, NULL);
1073                 TCP_INC_STATS_BH(net, TCP_MIB_OUTSEGS);
1074                 if (rst)
1075                         TCP_INC_STATS_BH(net, TCP_MIB_OUTRSTS);
1076                 return;
1077         }
1078
1079         kfree_skb(buff);
1080 }
1081
1082 static void tcp_v6_send_reset(struct sock *sk, struct sk_buff *skb)
1083 {
1084         struct tcphdr *th = tcp_hdr(skb);
1085         u32 seq = 0, ack_seq = 0;
1086         struct tcp_md5sig_key *key = NULL;
1087
1088         if (th->rst)
1089                 return;
1090
1091         if (!ipv6_unicast_destination(skb))
1092                 return;
1093
1094 #ifdef CONFIG_TCP_MD5SIG
1095         if (sk)
1096                 key = tcp_v6_md5_do_lookup(sk, &ipv6_hdr(skb)->daddr);
1097 #endif
1098
1099         if (th->ack)
1100                 seq = ntohl(th->ack_seq);
1101         else
1102                 ack_seq = ntohl(th->seq) + th->syn + th->fin + skb->len -
1103                           (th->doff << 2);
1104
1105         tcp_v6_send_response(skb, seq, ack_seq, 0, 0, key, 1);
1106 }
1107
1108 static void tcp_v6_send_ack(struct sk_buff *skb, u32 seq, u32 ack, u32 win, u32 ts,
1109                             struct tcp_md5sig_key *key)
1110 {
1111         tcp_v6_send_response(skb, seq, ack, win, ts, key, 0);
1112 }
1113
1114 static void tcp_v6_timewait_ack(struct sock *sk, struct sk_buff *skb)
1115 {
1116         struct inet_timewait_sock *tw = inet_twsk(sk);
1117         struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
1118
1119         tcp_v6_send_ack(skb, tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
1120                         tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
1121                         tcptw->tw_ts_recent, tcp_twsk_md5_key(tcptw));
1122
1123         inet_twsk_put(tw);
1124 }
1125
1126 static void tcp_v6_reqsk_send_ack(struct sock *sk, struct sk_buff *skb,
1127                                   struct request_sock *req)
1128 {
1129         tcp_v6_send_ack(skb, tcp_rsk(req)->snt_isn + 1, tcp_rsk(req)->rcv_isn + 1, req->rcv_wnd, req->ts_recent,
1130                         tcp_v6_md5_do_lookup(sk, &ipv6_hdr(skb)->daddr));
1131 }
1132
1133
1134 static struct sock *tcp_v6_hnd_req(struct sock *sk,struct sk_buff *skb)
1135 {
1136         struct request_sock *req, **prev;
1137         const struct tcphdr *th = tcp_hdr(skb);
1138         struct sock *nsk;
1139
1140         /* Find possible connection requests. */
1141         req = inet6_csk_search_req(sk, &prev, th->source,
1142                                    &ipv6_hdr(skb)->saddr,
1143                                    &ipv6_hdr(skb)->daddr, inet6_iif(skb));
1144         if (req)
1145                 return tcp_check_req(sk, skb, req, prev);
1146
1147         nsk = __inet6_lookup_established(sock_net(sk), &tcp_hashinfo,
1148                         &ipv6_hdr(skb)->saddr, th->source,
1149                         &ipv6_hdr(skb)->daddr, ntohs(th->dest), inet6_iif(skb));
1150
1151         if (nsk) {
1152                 if (nsk->sk_state != TCP_TIME_WAIT) {
1153                         bh_lock_sock(nsk);
1154                         return nsk;
1155                 }
1156                 inet_twsk_put(inet_twsk(nsk));
1157                 return NULL;
1158         }
1159
1160 #ifdef CONFIG_SYN_COOKIES
1161         if (!th->syn)
1162                 sk = cookie_v6_check(sk, skb);
1163 #endif
1164         return sk;
1165 }
1166
1167 /* FIXME: this is substantially similar to the ipv4 code.
1168  * Can some kind of merge be done? -- erics
1169  */
1170 static int tcp_v6_conn_request(struct sock *sk, struct sk_buff *skb)
1171 {
1172         struct tcp_extend_values tmp_ext;
1173         struct tcp_options_received tmp_opt;
1174         u8 *hash_location;
1175         struct request_sock *req;
1176         struct inet6_request_sock *treq;
1177         struct ipv6_pinfo *np = inet6_sk(sk);
1178         struct tcp_sock *tp = tcp_sk(sk);
1179         __u32 isn = TCP_SKB_CB(skb)->when;
1180         struct dst_entry *dst = NULL;
1181 #ifdef CONFIG_SYN_COOKIES
1182         int want_cookie = 0;
1183 #else
1184 #define want_cookie 0
1185 #endif
1186
1187         if (skb->protocol == htons(ETH_P_IP))
1188                 return tcp_v4_conn_request(sk, skb);
1189
1190         if (!ipv6_unicast_destination(skb))
1191                 goto drop;
1192
1193         if (inet_csk_reqsk_queue_is_full(sk) && !isn) {
1194                 if (net_ratelimit())
1195                         syn_flood_warning(skb);
1196 #ifdef CONFIG_SYN_COOKIES
1197                 if (sysctl_tcp_syncookies)
1198                         want_cookie = 1;
1199                 else
1200 #endif
1201                 goto drop;
1202         }
1203
1204         if (sk_acceptq_is_full(sk) && inet_csk_reqsk_queue_young(sk) > 1)
1205                 goto drop;
1206
1207         req = inet6_reqsk_alloc(&tcp6_request_sock_ops);
1208         if (req == NULL)
1209                 goto drop;
1210
1211 #ifdef CONFIG_TCP_MD5SIG
1212         tcp_rsk(req)->af_specific = &tcp_request_sock_ipv6_ops;
1213 #endif
1214
1215         tcp_clear_options(&tmp_opt);
1216         tmp_opt.mss_clamp = IPV6_MIN_MTU - sizeof(struct tcphdr) - sizeof(struct ipv6hdr);
1217         tmp_opt.user_mss = tp->rx_opt.user_mss;
1218         tcp_parse_options(skb, &tmp_opt, &hash_location, 0);
1219
1220         if (tmp_opt.cookie_plus > 0 &&
1221             tmp_opt.saw_tstamp &&
1222             !tp->rx_opt.cookie_out_never &&
1223             (sysctl_tcp_cookie_size > 0 ||
1224              (tp->cookie_values != NULL &&
1225               tp->cookie_values->cookie_desired > 0))) {
1226                 u8 *c;
1227                 u32 *d;
1228                 u32 *mess = &tmp_ext.cookie_bakery[COOKIE_DIGEST_WORDS];
1229                 int l = tmp_opt.cookie_plus - TCPOLEN_COOKIE_BASE;
1230
1231                 if (tcp_cookie_generator(&tmp_ext.cookie_bakery[0]) != 0)
1232                         goto drop_and_free;
1233
1234                 /* Secret recipe starts with IP addresses */
1235                 d = (__force u32 *)&ipv6_hdr(skb)->daddr.s6_addr32[0];
1236                 *mess++ ^= *d++;
1237                 *mess++ ^= *d++;
1238                 *mess++ ^= *d++;
1239                 *mess++ ^= *d++;
1240                 d = (__force u32 *)&ipv6_hdr(skb)->saddr.s6_addr32[0];
1241                 *mess++ ^= *d++;
1242                 *mess++ ^= *d++;
1243                 *mess++ ^= *d++;
1244                 *mess++ ^= *d++;
1245
1246                 /* plus variable length Initiator Cookie */
1247                 c = (u8 *)mess;
1248                 while (l-- > 0)
1249                         *c++ ^= *hash_location++;
1250
1251 #ifdef CONFIG_SYN_COOKIES
1252                 want_cookie = 0;        /* not our kind of cookie */
1253 #endif
1254                 tmp_ext.cookie_out_never = 0; /* false */
1255                 tmp_ext.cookie_plus = tmp_opt.cookie_plus;
1256         } else if (!tp->rx_opt.cookie_in_always) {
1257                 /* redundant indications, but ensure initialization. */
1258                 tmp_ext.cookie_out_never = 1; /* true */
1259                 tmp_ext.cookie_plus = 0;
1260         } else {
1261                 goto drop_and_free;
1262         }
1263         tmp_ext.cookie_in_always = tp->rx_opt.cookie_in_always;
1264
1265         if (want_cookie && !tmp_opt.saw_tstamp)
1266                 tcp_clear_options(&tmp_opt);
1267
1268         tmp_opt.tstamp_ok = tmp_opt.saw_tstamp;
1269         tcp_openreq_init(req, &tmp_opt, skb);
1270
1271         treq = inet6_rsk(req);
1272         ipv6_addr_copy(&treq->rmt_addr, &ipv6_hdr(skb)->saddr);
1273         ipv6_addr_copy(&treq->loc_addr, &ipv6_hdr(skb)->daddr);
1274         if (!want_cookie || tmp_opt.tstamp_ok)
1275                 TCP_ECN_create_request(req, tcp_hdr(skb));
1276
1277         if (!isn) {
1278                 struct inet_peer *peer = NULL;
1279
1280                 if (ipv6_opt_accepted(sk, skb) ||
1281                     np->rxopt.bits.rxinfo || np->rxopt.bits.rxoinfo ||
1282                     np->rxopt.bits.rxhlim || np->rxopt.bits.rxohlim) {
1283                         atomic_inc(&skb->users);
1284                         treq->pktopts = skb;
1285                 }
1286                 treq->iif = sk->sk_bound_dev_if;
1287
1288                 /* So that link locals have meaning */
1289                 if (!sk->sk_bound_dev_if &&
1290                     ipv6_addr_type(&treq->rmt_addr) & IPV6_ADDR_LINKLOCAL)
1291                         treq->iif = inet6_iif(skb);
1292
1293                 if (want_cookie) {
1294                         isn = cookie_v6_init_sequence(sk, skb, &req->mss);
1295                         req->cookie_ts = tmp_opt.tstamp_ok;
1296                         goto have_isn;
1297                 }
1298
1299                 /* VJ's idea. We save last timestamp seen
1300                  * from the destination in peer table, when entering
1301                  * state TIME-WAIT, and check against it before
1302                  * accepting new connection request.
1303                  *
1304                  * If "isn" is not zero, this request hit alive
1305                  * timewait bucket, so that all the necessary checks
1306                  * are made in the function processing timewait state.
1307                  */
1308                 if (tmp_opt.saw_tstamp &&
1309                     tcp_death_row.sysctl_tw_recycle &&
1310                     (dst = inet6_csk_route_req(sk, req)) != NULL &&
1311                     (peer = rt6_get_peer((struct rt6_info *)dst)) != NULL &&
1312                     ipv6_addr_equal((struct in6_addr *)peer->daddr.addr.a6,
1313                                     &treq->rmt_addr)) {
1314                         inet_peer_refcheck(peer);
1315                         if ((u32)get_seconds() - peer->tcp_ts_stamp < TCP_PAWS_MSL &&
1316                             (s32)(peer->tcp_ts - req->ts_recent) >
1317                                                         TCP_PAWS_WINDOW) {
1318                                 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_PAWSPASSIVEREJECTED);
1319                                 goto drop_and_release;
1320                         }
1321                 }
1322                 /* Kill the following clause, if you dislike this way. */
1323                 else if (!sysctl_tcp_syncookies &&
1324                          (sysctl_max_syn_backlog - inet_csk_reqsk_queue_len(sk) <
1325                           (sysctl_max_syn_backlog >> 2)) &&
1326                          (!peer || !peer->tcp_ts_stamp) &&
1327                          (!dst || !dst_metric(dst, RTAX_RTT))) {
1328                         /* Without syncookies last quarter of
1329                          * backlog is filled with destinations,
1330                          * proven to be alive.
1331                          * It means that we continue to communicate
1332                          * to destinations, already remembered
1333                          * to the moment of synflood.
1334                          */
1335                         LIMIT_NETDEBUG(KERN_DEBUG "TCP: drop open request from %pI6/%u\n",
1336                                        &treq->rmt_addr, ntohs(tcp_hdr(skb)->source));
1337                         goto drop_and_release;
1338                 }
1339
1340                 isn = tcp_v6_init_sequence(skb);
1341         }
1342 have_isn:
1343         tcp_rsk(req)->snt_isn = isn;
1344
1345         security_inet_conn_request(sk, skb, req);
1346
1347         if (tcp_v6_send_synack(sk, req,
1348                                (struct request_values *)&tmp_ext) ||
1349             want_cookie)
1350                 goto drop_and_free;
1351
1352         inet6_csk_reqsk_queue_hash_add(sk, req, TCP_TIMEOUT_INIT);
1353         return 0;
1354
1355 drop_and_release:
1356         dst_release(dst);
1357 drop_and_free:
1358         reqsk_free(req);
1359 drop:
1360         return 0; /* don't send reset */
1361 }
1362
1363 static struct sock * tcp_v6_syn_recv_sock(struct sock *sk, struct sk_buff *skb,
1364                                           struct request_sock *req,
1365                                           struct dst_entry *dst)
1366 {
1367         struct inet6_request_sock *treq;
1368         struct ipv6_pinfo *newnp, *np = inet6_sk(sk);
1369         struct tcp6_sock *newtcp6sk;
1370         struct inet_sock *newinet;
1371         struct tcp_sock *newtp;
1372         struct sock *newsk;
1373         struct ipv6_txoptions *opt;
1374 #ifdef CONFIG_TCP_MD5SIG
1375         struct tcp_md5sig_key *key;
1376 #endif
1377
1378         if (skb->protocol == htons(ETH_P_IP)) {
1379                 /*
1380                  *      v6 mapped
1381                  */
1382
1383                 newsk = tcp_v4_syn_recv_sock(sk, skb, req, dst);
1384
1385                 if (newsk == NULL)
1386                         return NULL;
1387
1388                 newtcp6sk = (struct tcp6_sock *)newsk;
1389                 inet_sk(newsk)->pinet6 = &newtcp6sk->inet6;
1390
1391                 newinet = inet_sk(newsk);
1392                 newnp = inet6_sk(newsk);
1393                 newtp = tcp_sk(newsk);
1394
1395                 memcpy(newnp, np, sizeof(struct ipv6_pinfo));
1396
1397                 ipv6_addr_set_v4mapped(newinet->inet_daddr, &newnp->daddr);
1398
1399                 ipv6_addr_set_v4mapped(newinet->inet_saddr, &newnp->saddr);
1400
1401                 ipv6_addr_copy(&newnp->rcv_saddr, &newnp->saddr);
1402
1403                 inet_csk(newsk)->icsk_af_ops = &ipv6_mapped;
1404                 newsk->sk_backlog_rcv = tcp_v4_do_rcv;
1405 #ifdef CONFIG_TCP_MD5SIG
1406                 newtp->af_specific = &tcp_sock_ipv6_mapped_specific;
1407 #endif
1408
1409                 newnp->pktoptions  = NULL;
1410                 newnp->opt         = NULL;
1411                 newnp->mcast_oif   = inet6_iif(skb);
1412                 newnp->mcast_hops  = ipv6_hdr(skb)->hop_limit;
1413
1414                 /*
1415                  * No need to charge this sock to the relevant IPv6 refcnt debug socks count
1416                  * here, tcp_create_openreq_child now does this for us, see the comment in
1417                  * that function for the gory details. -acme
1418                  */
1419
1420                 /* It is tricky place. Until this moment IPv4 tcp
1421                    worked with IPv6 icsk.icsk_af_ops.
1422                    Sync it now.
1423                  */
1424                 tcp_sync_mss(newsk, inet_csk(newsk)->icsk_pmtu_cookie);
1425
1426                 return newsk;
1427         }
1428
1429         treq = inet6_rsk(req);
1430         opt = np->opt;
1431
1432         if (sk_acceptq_is_full(sk))
1433                 goto out_overflow;
1434
1435         if (!dst) {
1436                 dst = inet6_csk_route_req(sk, req);
1437                 if (!dst)
1438                         goto out;
1439         }
1440
1441         newsk = tcp_create_openreq_child(sk, req, skb);
1442         if (newsk == NULL)
1443                 goto out_nonewsk;
1444
1445         /*
1446          * No need to charge this sock to the relevant IPv6 refcnt debug socks
1447          * count here, tcp_create_openreq_child now does this for us, see the
1448          * comment in that function for the gory details. -acme
1449          */
1450
1451         newsk->sk_gso_type = SKB_GSO_TCPV6;
1452         __ip6_dst_store(newsk, dst, NULL, NULL);
1453
1454         newtcp6sk = (struct tcp6_sock *)newsk;
1455         inet_sk(newsk)->pinet6 = &newtcp6sk->inet6;
1456
1457         newtp = tcp_sk(newsk);
1458         newinet = inet_sk(newsk);
1459         newnp = inet6_sk(newsk);
1460
1461         memcpy(newnp, np, sizeof(struct ipv6_pinfo));
1462
1463         ipv6_addr_copy(&newnp->daddr, &treq->rmt_addr);
1464         ipv6_addr_copy(&newnp->saddr, &treq->loc_addr);
1465         ipv6_addr_copy(&newnp->rcv_saddr, &treq->loc_addr);
1466         newsk->sk_bound_dev_if = treq->iif;
1467
1468         /* Now IPv6 options...
1469
1470            First: no IPv4 options.
1471          */
1472         newinet->inet_opt = NULL;
1473         newnp->ipv6_fl_list = NULL;
1474
1475         /* Clone RX bits */
1476         newnp->rxopt.all = np->rxopt.all;
1477
1478         /* Clone pktoptions received with SYN */
1479         newnp->pktoptions = NULL;
1480         if (treq->pktopts != NULL) {
1481                 newnp->pktoptions = skb_clone(treq->pktopts, GFP_ATOMIC);
1482                 kfree_skb(treq->pktopts);
1483                 treq->pktopts = NULL;
1484                 if (newnp->pktoptions)
1485                         skb_set_owner_r(newnp->pktoptions, newsk);
1486         }
1487         newnp->opt        = NULL;
1488         newnp->mcast_oif  = inet6_iif(skb);
1489         newnp->mcast_hops = ipv6_hdr(skb)->hop_limit;
1490
1491         /* Clone native IPv6 options from listening socket (if any)
1492
1493            Yes, keeping reference count would be much more clever,
1494            but we make one more one thing there: reattach optmem
1495            to newsk.
1496          */
1497         if (opt) {
1498                 newnp->opt = ipv6_dup_options(newsk, opt);
1499                 if (opt != np->opt)
1500                         sock_kfree_s(sk, opt, opt->tot_len);
1501         }
1502
1503         inet_csk(newsk)->icsk_ext_hdr_len = 0;
1504         if (newnp->opt)
1505                 inet_csk(newsk)->icsk_ext_hdr_len = (newnp->opt->opt_nflen +
1506                                                      newnp->opt->opt_flen);
1507
1508         tcp_mtup_init(newsk);
1509         tcp_sync_mss(newsk, dst_mtu(dst));
1510         newtp->advmss = dst_metric_advmss(dst);
1511         tcp_initialize_rcv_mss(newsk);
1512
1513         newinet->inet_daddr = newinet->inet_saddr = LOOPBACK4_IPV6;
1514         newinet->inet_rcv_saddr = LOOPBACK4_IPV6;
1515
1516 #ifdef CONFIG_TCP_MD5SIG
1517         /* Copy over the MD5 key from the original socket */
1518         if ((key = tcp_v6_md5_do_lookup(sk, &newnp->daddr)) != NULL) {
1519                 /* We're using one, so create a matching key
1520                  * on the newsk structure. If we fail to get
1521                  * memory, then we end up not copying the key
1522                  * across. Shucks.
1523                  */
1524                 char *newkey = kmemdup(key->key, key->keylen, GFP_ATOMIC);
1525                 if (newkey != NULL)
1526                         tcp_v6_md5_do_add(newsk, &newnp->daddr,
1527                                           newkey, key->keylen);
1528         }
1529 #endif
1530
1531         if (__inet_inherit_port(sk, newsk) < 0) {
1532                 sock_put(newsk);
1533                 goto out;
1534         }
1535         __inet6_hash(newsk, NULL);
1536
1537         return newsk;
1538
1539 out_overflow:
1540         NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
1541 out_nonewsk:
1542         if (opt && opt != np->opt)
1543                 sock_kfree_s(sk, opt, opt->tot_len);
1544         dst_release(dst);
1545 out:
1546         NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
1547         return NULL;
1548 }
1549
1550 static __sum16 tcp_v6_checksum_init(struct sk_buff *skb)
1551 {
1552         if (skb->ip_summed == CHECKSUM_COMPLETE) {
1553                 if (!tcp_v6_check(skb->len, &ipv6_hdr(skb)->saddr,
1554                                   &ipv6_hdr(skb)->daddr, skb->csum)) {
1555                         skb->ip_summed = CHECKSUM_UNNECESSARY;
1556                         return 0;
1557                 }
1558         }
1559
1560         skb->csum = ~csum_unfold(tcp_v6_check(skb->len,
1561                                               &ipv6_hdr(skb)->saddr,
1562                                               &ipv6_hdr(skb)->daddr, 0));
1563
1564         if (skb->len <= 76) {
1565                 return __skb_checksum_complete(skb);
1566         }
1567         return 0;
1568 }
1569
1570 /* The socket must have it's spinlock held when we get
1571  * here.
1572  *
1573  * We have a potential double-lock case here, so even when
1574  * doing backlog processing we use the BH locking scheme.
1575  * This is because we cannot sleep with the original spinlock
1576  * held.
1577  */
1578 static int tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb)
1579 {
1580         struct ipv6_pinfo *np = inet6_sk(sk);
1581         struct tcp_sock *tp;
1582         struct sk_buff *opt_skb = NULL;
1583
1584         /* Imagine: socket is IPv6. IPv4 packet arrives,
1585            goes to IPv4 receive handler and backlogged.
1586            From backlog it always goes here. Kerboom...
1587            Fortunately, tcp_rcv_established and rcv_established
1588            handle them correctly, but it is not case with
1589            tcp_v6_hnd_req and tcp_v6_send_reset().   --ANK
1590          */
1591
1592         if (skb->protocol == htons(ETH_P_IP))
1593                 return tcp_v4_do_rcv(sk, skb);
1594
1595 #ifdef CONFIG_TCP_MD5SIG
1596         if (tcp_v6_inbound_md5_hash (sk, skb))
1597                 goto discard;
1598 #endif
1599
1600         if (sk_filter(sk, skb))
1601                 goto discard;
1602
1603         /*
1604          *      socket locking is here for SMP purposes as backlog rcv
1605          *      is currently called with bh processing disabled.
1606          */
1607
1608         /* Do Stevens' IPV6_PKTOPTIONS.
1609
1610            Yes, guys, it is the only place in our code, where we
1611            may make it not affecting IPv4.
1612            The rest of code is protocol independent,
1613            and I do not like idea to uglify IPv4.
1614
1615            Actually, all the idea behind IPV6_PKTOPTIONS
1616            looks not very well thought. For now we latch
1617            options, received in the last packet, enqueued
1618            by tcp. Feel free to propose better solution.
1619                                                --ANK (980728)
1620          */
1621         if (np->rxopt.all)
1622                 opt_skb = skb_clone(skb, GFP_ATOMIC);
1623
1624         if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
1625                 sock_rps_save_rxhash(sk, skb->rxhash);
1626                 if (tcp_rcv_established(sk, skb, tcp_hdr(skb), skb->len))
1627                         goto reset;
1628                 if (opt_skb)
1629                         goto ipv6_pktoptions;
1630                 return 0;
1631         }
1632
1633         if (skb->len < tcp_hdrlen(skb) || tcp_checksum_complete(skb))
1634                 goto csum_err;
1635
1636         if (sk->sk_state == TCP_LISTEN) {
1637                 struct sock *nsk = tcp_v6_hnd_req(sk, skb);
1638                 if (!nsk)
1639                         goto discard;
1640
1641                 /*
1642                  * Queue it on the new socket if the new socket is active,
1643                  * otherwise we just shortcircuit this and continue with
1644                  * the new socket..
1645                  */
1646                 if(nsk != sk) {
1647                         sock_rps_save_rxhash(nsk, skb->rxhash);
1648                         if (tcp_child_process(sk, nsk, skb))
1649                                 goto reset;
1650                         if (opt_skb)
1651                                 __kfree_skb(opt_skb);
1652                         return 0;
1653                 }
1654         } else
1655                 sock_rps_save_rxhash(sk, skb->rxhash);
1656
1657         if (tcp_rcv_state_process(sk, skb, tcp_hdr(skb), skb->len))
1658                 goto reset;
1659         if (opt_skb)
1660                 goto ipv6_pktoptions;
1661         return 0;
1662
1663 reset:
1664         tcp_v6_send_reset(sk, skb);
1665 discard:
1666         if (opt_skb)
1667                 __kfree_skb(opt_skb);
1668         kfree_skb(skb);
1669         return 0;
1670 csum_err:
1671         TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_INERRS);
1672         goto discard;
1673
1674
1675 ipv6_pktoptions:
1676         /* Do you ask, what is it?
1677
1678            1. skb was enqueued by tcp.
1679            2. skb is added to tail of read queue, rather than out of order.
1680            3. socket is not in passive state.
1681            4. Finally, it really contains options, which user wants to receive.
1682          */
1683         tp = tcp_sk(sk);
1684         if (TCP_SKB_CB(opt_skb)->end_seq == tp->rcv_nxt &&
1685             !((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN))) {
1686                 if (np->rxopt.bits.rxinfo || np->rxopt.bits.rxoinfo)
1687                         np->mcast_oif = inet6_iif(opt_skb);
1688                 if (np->rxopt.bits.rxhlim || np->rxopt.bits.rxohlim)
1689                         np->mcast_hops = ipv6_hdr(opt_skb)->hop_limit;
1690                 if (ipv6_opt_accepted(sk, opt_skb)) {
1691                         skb_set_owner_r(opt_skb, sk);
1692                         opt_skb = xchg(&np->pktoptions, opt_skb);
1693                 } else {
1694                         __kfree_skb(opt_skb);
1695                         opt_skb = xchg(&np->pktoptions, NULL);
1696                 }
1697         }
1698
1699         kfree_skb(opt_skb);
1700         return 0;
1701 }
1702
1703 static int tcp_v6_rcv(struct sk_buff *skb)
1704 {
1705         struct tcphdr *th;
1706         const struct ipv6hdr *hdr;
1707         struct sock *sk;
1708         int ret;
1709         struct net *net = dev_net(skb->dev);
1710
1711         if (skb->pkt_type != PACKET_HOST)
1712                 goto discard_it;
1713
1714         /*
1715          *      Count it even if it's bad.
1716          */
1717         TCP_INC_STATS_BH(net, TCP_MIB_INSEGS);
1718
1719         if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
1720                 goto discard_it;
1721
1722         th = tcp_hdr(skb);
1723
1724         if (th->doff < sizeof(struct tcphdr)/4)
1725                 goto bad_packet;
1726         if (!pskb_may_pull(skb, th->doff*4))
1727                 goto discard_it;
1728
1729         if (!skb_csum_unnecessary(skb) && tcp_v6_checksum_init(skb))
1730                 goto bad_packet;
1731
1732         th = tcp_hdr(skb);
1733         hdr = ipv6_hdr(skb);
1734         TCP_SKB_CB(skb)->seq = ntohl(th->seq);
1735         TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
1736                                     skb->len - th->doff*4);
1737         TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
1738         TCP_SKB_CB(skb)->when = 0;
1739         TCP_SKB_CB(skb)->flags = ipv6_get_dsfield(hdr);
1740         TCP_SKB_CB(skb)->sacked = 0;
1741
1742         sk = __inet6_lookup_skb(&tcp_hashinfo, skb, th->source, th->dest);
1743         if (!sk)
1744                 goto no_tcp_socket;
1745
1746 process:
1747         if (sk->sk_state == TCP_TIME_WAIT)
1748                 goto do_time_wait;
1749
1750         if (hdr->hop_limit < inet6_sk(sk)->min_hopcount) {
1751                 NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP);
1752                 goto discard_and_relse;
1753         }
1754
1755         if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb))
1756                 goto discard_and_relse;
1757
1758         if (sk_filter(sk, skb))
1759                 goto discard_and_relse;
1760
1761         skb->dev = NULL;
1762
1763         bh_lock_sock_nested(sk);
1764         ret = 0;
1765         if (!sock_owned_by_user(sk)) {
1766 #ifdef CONFIG_NET_DMA
1767                 struct tcp_sock *tp = tcp_sk(sk);
1768                 if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list)
1769                         tp->ucopy.dma_chan = dma_find_channel(DMA_MEMCPY);
1770                 if (tp->ucopy.dma_chan)
1771                         ret = tcp_v6_do_rcv(sk, skb);
1772                 else
1773 #endif
1774                 {
1775                         if (!tcp_prequeue(sk, skb))
1776                                 ret = tcp_v6_do_rcv(sk, skb);
1777                 }
1778         } else if (unlikely(sk_add_backlog(sk, skb))) {
1779                 bh_unlock_sock(sk);
1780                 NET_INC_STATS_BH(net, LINUX_MIB_TCPBACKLOGDROP);
1781                 goto discard_and_relse;
1782         }
1783         bh_unlock_sock(sk);
1784
1785         sock_put(sk);
1786         return ret ? -1 : 0;
1787
1788 no_tcp_socket:
1789         if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb))
1790                 goto discard_it;
1791
1792         if (skb->len < (th->doff<<2) || tcp_checksum_complete(skb)) {
1793 bad_packet:
1794                 TCP_INC_STATS_BH(net, TCP_MIB_INERRS);
1795         } else {
1796                 tcp_v6_send_reset(NULL, skb);
1797         }
1798
1799 discard_it:
1800
1801         /*
1802          *      Discard frame
1803          */
1804
1805         kfree_skb(skb);
1806         return 0;
1807
1808 discard_and_relse:
1809         sock_put(sk);
1810         goto discard_it;
1811
1812 do_time_wait:
1813         if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
1814                 inet_twsk_put(inet_twsk(sk));
1815                 goto discard_it;
1816         }
1817
1818         if (skb->len < (th->doff<<2) || tcp_checksum_complete(skb)) {
1819                 TCP_INC_STATS_BH(net, TCP_MIB_INERRS);
1820                 inet_twsk_put(inet_twsk(sk));
1821                 goto discard_it;
1822         }
1823
1824         switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) {
1825         case TCP_TW_SYN:
1826         {
1827                 struct sock *sk2;
1828
1829                 sk2 = inet6_lookup_listener(dev_net(skb->dev), &tcp_hashinfo,
1830                                             &ipv6_hdr(skb)->daddr,
1831                                             ntohs(th->dest), inet6_iif(skb));
1832                 if (sk2 != NULL) {
1833                         struct inet_timewait_sock *tw = inet_twsk(sk);
1834                         inet_twsk_deschedule(tw, &tcp_death_row);
1835                         inet_twsk_put(tw);
1836                         sk = sk2;
1837                         goto process;
1838                 }
1839                 /* Fall through to ACK */
1840         }
1841         case TCP_TW_ACK:
1842                 tcp_v6_timewait_ack(sk, skb);
1843                 break;
1844         case TCP_TW_RST:
1845                 goto no_tcp_socket;
1846         case TCP_TW_SUCCESS:;
1847         }
1848         goto discard_it;
1849 }
1850
1851 static struct inet_peer *tcp_v6_get_peer(struct sock *sk, bool *release_it)
1852 {
1853         struct rt6_info *rt = (struct rt6_info *) __sk_dst_get(sk);
1854         struct ipv6_pinfo *np = inet6_sk(sk);
1855         struct inet_peer *peer;
1856
1857         if (!rt ||
1858             !ipv6_addr_equal(&np->daddr, &rt->rt6i_dst.addr)) {
1859                 peer = inet_getpeer_v6(&np->daddr, 1);
1860                 *release_it = true;
1861         } else {
1862                 if (!rt->rt6i_peer)
1863                         rt6_bind_peer(rt, 1);
1864                 peer = rt->rt6i_peer;
1865                 *release_it = false;
1866         }
1867
1868         return peer;
1869 }
1870
1871 static void *tcp_v6_tw_get_peer(struct sock *sk)
1872 {
1873         struct inet6_timewait_sock *tw6 = inet6_twsk(sk);
1874         struct inet_timewait_sock *tw = inet_twsk(sk);
1875
1876         if (tw->tw_family == AF_INET)
1877                 return tcp_v4_tw_get_peer(sk);
1878
1879         return inet_getpeer_v6(&tw6->tw_v6_daddr, 1);
1880 }
1881
1882 static struct timewait_sock_ops tcp6_timewait_sock_ops = {
1883         .twsk_obj_size  = sizeof(struct tcp6_timewait_sock),
1884         .twsk_unique    = tcp_twsk_unique,
1885         .twsk_destructor= tcp_twsk_destructor,
1886         .twsk_getpeer   = tcp_v6_tw_get_peer,
1887 };
1888
1889 static const struct inet_connection_sock_af_ops ipv6_specific = {
1890         .queue_xmit        = inet6_csk_xmit,
1891         .send_check        = tcp_v6_send_check,
1892         .rebuild_header    = inet6_sk_rebuild_header,
1893         .conn_request      = tcp_v6_conn_request,
1894         .syn_recv_sock     = tcp_v6_syn_recv_sock,
1895         .get_peer          = tcp_v6_get_peer,
1896         .net_header_len    = sizeof(struct ipv6hdr),
1897         .setsockopt        = ipv6_setsockopt,
1898         .getsockopt        = ipv6_getsockopt,
1899         .addr2sockaddr     = inet6_csk_addr2sockaddr,
1900         .sockaddr_len      = sizeof(struct sockaddr_in6),
1901         .bind_conflict     = inet6_csk_bind_conflict,
1902 #ifdef CONFIG_COMPAT
1903         .compat_setsockopt = compat_ipv6_setsockopt,
1904         .compat_getsockopt = compat_ipv6_getsockopt,
1905 #endif
1906 };
1907
1908 #ifdef CONFIG_TCP_MD5SIG
1909 static const struct tcp_sock_af_ops tcp_sock_ipv6_specific = {
1910         .md5_lookup     =       tcp_v6_md5_lookup,
1911         .calc_md5_hash  =       tcp_v6_md5_hash_skb,
1912         .md5_add        =       tcp_v6_md5_add_func,
1913         .md5_parse      =       tcp_v6_parse_md5_keys,
1914 };
1915 #endif
1916
1917 /*
1918  *      TCP over IPv4 via INET6 API
1919  */
1920
1921 static const struct inet_connection_sock_af_ops ipv6_mapped = {
1922         .queue_xmit        = ip_queue_xmit,
1923         .send_check        = tcp_v4_send_check,
1924         .rebuild_header    = inet_sk_rebuild_header,
1925         .conn_request      = tcp_v6_conn_request,
1926         .syn_recv_sock     = tcp_v6_syn_recv_sock,
1927         .get_peer          = tcp_v4_get_peer,
1928         .net_header_len    = sizeof(struct iphdr),
1929         .setsockopt        = ipv6_setsockopt,
1930         .getsockopt        = ipv6_getsockopt,
1931         .addr2sockaddr     = inet6_csk_addr2sockaddr,
1932         .sockaddr_len      = sizeof(struct sockaddr_in6),
1933         .bind_conflict     = inet6_csk_bind_conflict,
1934 #ifdef CONFIG_COMPAT
1935         .compat_setsockopt = compat_ipv6_setsockopt,
1936         .compat_getsockopt = compat_ipv6_getsockopt,
1937 #endif
1938 };
1939
1940 #ifdef CONFIG_TCP_MD5SIG
1941 static const struct tcp_sock_af_ops tcp_sock_ipv6_mapped_specific = {
1942         .md5_lookup     =       tcp_v4_md5_lookup,
1943         .calc_md5_hash  =       tcp_v4_md5_hash_skb,
1944         .md5_add        =       tcp_v6_md5_add_func,
1945         .md5_parse      =       tcp_v6_parse_md5_keys,
1946 };
1947 #endif
1948
1949 /* NOTE: A lot of things set to zero explicitly by call to
1950  *       sk_alloc() so need not be done here.
1951  */
1952 static int tcp_v6_init_sock(struct sock *sk)
1953 {
1954         struct inet_connection_sock *icsk = inet_csk(sk);
1955         struct tcp_sock *tp = tcp_sk(sk);
1956
1957         skb_queue_head_init(&tp->out_of_order_queue);
1958         tcp_init_xmit_timers(sk);
1959         tcp_prequeue_init(tp);
1960
1961         icsk->icsk_rto = TCP_TIMEOUT_INIT;
1962         tp->mdev = TCP_TIMEOUT_INIT;
1963
1964         /* So many TCP implementations out there (incorrectly) count the
1965          * initial SYN frame in their delayed-ACK and congestion control
1966          * algorithms that we must have the following bandaid to talk
1967          * efficiently to them.  -DaveM
1968          */
1969         tp->snd_cwnd = 2;
1970
1971         /* See draft-stevens-tcpca-spec-01 for discussion of the
1972          * initialization of these values.
1973          */
1974         tp->snd_ssthresh = TCP_INFINITE_SSTHRESH;
1975         tp->snd_cwnd_clamp = ~0;
1976         tp->mss_cache = TCP_MSS_DEFAULT;
1977
1978         tp->reordering = sysctl_tcp_reordering;
1979
1980         sk->sk_state = TCP_CLOSE;
1981
1982         icsk->icsk_af_ops = &ipv6_specific;
1983         icsk->icsk_ca_ops = &tcp_init_congestion_ops;
1984         icsk->icsk_sync_mss = tcp_sync_mss;
1985         sk->sk_write_space = sk_stream_write_space;
1986         sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
1987
1988 #ifdef CONFIG_TCP_MD5SIG
1989         tp->af_specific = &tcp_sock_ipv6_specific;
1990 #endif
1991
1992         /* TCP Cookie Transactions */
1993         if (sysctl_tcp_cookie_size > 0) {
1994                 /* Default, cookies without s_data_payload. */
1995                 tp->cookie_values =
1996                         kzalloc(sizeof(*tp->cookie_values),
1997                                 sk->sk_allocation);
1998                 if (tp->cookie_values != NULL)
1999                         kref_init(&tp->cookie_values->kref);
2000         }
2001         /* Presumed zeroed, in order of appearance:
2002          *      cookie_in_always, cookie_out_never,
2003          *      s_data_constant, s_data_in, s_data_out
2004          */
2005         sk->sk_sndbuf = sysctl_tcp_wmem[1];
2006         sk->sk_rcvbuf = sysctl_tcp_rmem[1];
2007
2008         local_bh_disable();
2009         percpu_counter_inc(&tcp_sockets_allocated);
2010         local_bh_enable();
2011
2012         return 0;
2013 }
2014
2015 static void tcp_v6_destroy_sock(struct sock *sk)
2016 {
2017 #ifdef CONFIG_TCP_MD5SIG
2018         /* Clean up the MD5 key list */
2019         if (tcp_sk(sk)->md5sig_info)
2020                 tcp_v6_clear_md5_list(sk);
2021 #endif
2022         tcp_v4_destroy_sock(sk);
2023         inet6_destroy_sock(sk);
2024 }
2025
2026 #ifdef CONFIG_PROC_FS
2027 /* Proc filesystem TCPv6 sock list dumping. */
2028 static void get_openreq6(struct seq_file *seq,
2029                          struct sock *sk, struct request_sock *req, int i, int uid)
2030 {
2031         int ttd = req->expires - jiffies;
2032         const struct in6_addr *src = &inet6_rsk(req)->loc_addr;
2033         const struct in6_addr *dest = &inet6_rsk(req)->rmt_addr;
2034
2035         if (ttd < 0)
2036                 ttd = 0;
2037
2038         seq_printf(seq,
2039                    "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
2040                    "%02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK\n",
2041                    i,
2042                    src->s6_addr32[0], src->s6_addr32[1],
2043                    src->s6_addr32[2], src->s6_addr32[3],
2044                    ntohs(inet_rsk(req)->loc_port),
2045                    dest->s6_addr32[0], dest->s6_addr32[1],
2046                    dest->s6_addr32[2], dest->s6_addr32[3],
2047                    ntohs(inet_rsk(req)->rmt_port),
2048                    TCP_SYN_RECV,
2049                    0,0, /* could print option size, but that is af dependent. */
2050                    1,   /* timers active (only the expire timer) */
2051                    jiffies_to_clock_t(ttd),
2052                    req->retrans,
2053                    uid,
2054                    0,  /* non standard timer */
2055                    0, /* open_requests have no inode */
2056                    0, req);
2057 }
2058
2059 static void get_tcp6_sock(struct seq_file *seq, struct sock *sp, int i)
2060 {
2061         const struct in6_addr *dest, *src;
2062         __u16 destp, srcp;
2063         int timer_active;
2064         unsigned long timer_expires;
2065         struct inet_sock *inet = inet_sk(sp);
2066         struct tcp_sock *tp = tcp_sk(sp);
2067         const struct inet_connection_sock *icsk = inet_csk(sp);
2068         struct ipv6_pinfo *np = inet6_sk(sp);
2069
2070         dest  = &np->daddr;
2071         src   = &np->rcv_saddr;
2072         destp = ntohs(inet->inet_dport);
2073         srcp  = ntohs(inet->inet_sport);
2074
2075         if (icsk->icsk_pending == ICSK_TIME_RETRANS) {
2076                 timer_active    = 1;
2077                 timer_expires   = icsk->icsk_timeout;
2078         } else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
2079                 timer_active    = 4;
2080                 timer_expires   = icsk->icsk_timeout;
2081         } else if (timer_pending(&sp->sk_timer)) {
2082                 timer_active    = 2;
2083                 timer_expires   = sp->sk_timer.expires;
2084         } else {
2085                 timer_active    = 0;
2086                 timer_expires = jiffies;
2087         }
2088
2089         seq_printf(seq,
2090                    "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
2091                    "%02X %08X:%08X %02X:%08lX %08X %5d %8d %lu %d %pK %lu %lu %u %u %d\n",
2092                    i,
2093                    src->s6_addr32[0], src->s6_addr32[1],
2094                    src->s6_addr32[2], src->s6_addr32[3], srcp,
2095                    dest->s6_addr32[0], dest->s6_addr32[1],
2096                    dest->s6_addr32[2], dest->s6_addr32[3], destp,
2097                    sp->sk_state,
2098                    tp->write_seq-tp->snd_una,
2099                    (sp->sk_state == TCP_LISTEN) ? sp->sk_ack_backlog : (tp->rcv_nxt - tp->copied_seq),
2100                    timer_active,
2101                    jiffies_to_clock_t(timer_expires - jiffies),
2102                    icsk->icsk_retransmits,
2103                    sock_i_uid(sp),
2104                    icsk->icsk_probes_out,
2105                    sock_i_ino(sp),
2106                    atomic_read(&sp->sk_refcnt), sp,
2107                    jiffies_to_clock_t(icsk->icsk_rto),
2108                    jiffies_to_clock_t(icsk->icsk_ack.ato),
2109                    (icsk->icsk_ack.quick << 1 ) | icsk->icsk_ack.pingpong,
2110                    tp->snd_cwnd,
2111                    tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh
2112                    );
2113 }
2114
2115 static void get_timewait6_sock(struct seq_file *seq,
2116                                struct inet_timewait_sock *tw, int i)
2117 {
2118         const struct in6_addr *dest, *src;
2119         __u16 destp, srcp;
2120         struct inet6_timewait_sock *tw6 = inet6_twsk((struct sock *)tw);
2121         int ttd = tw->tw_ttd - jiffies;
2122
2123         if (ttd < 0)
2124                 ttd = 0;
2125
2126         dest = &tw6->tw_v6_daddr;
2127         src  = &tw6->tw_v6_rcv_saddr;
2128         destp = ntohs(tw->tw_dport);
2129         srcp  = ntohs(tw->tw_sport);
2130
2131         seq_printf(seq,
2132                    "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
2133                    "%02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK\n",
2134                    i,
2135                    src->s6_addr32[0], src->s6_addr32[1],
2136                    src->s6_addr32[2], src->s6_addr32[3], srcp,
2137                    dest->s6_addr32[0], dest->s6_addr32[1],
2138                    dest->s6_addr32[2], dest->s6_addr32[3], destp,
2139                    tw->tw_substate, 0, 0,
2140                    3, jiffies_to_clock_t(ttd), 0, 0, 0, 0,
2141                    atomic_read(&tw->tw_refcnt), tw);
2142 }
2143
2144 static int tcp6_seq_show(struct seq_file *seq, void *v)
2145 {
2146         struct tcp_iter_state *st;
2147
2148         if (v == SEQ_START_TOKEN) {
2149                 seq_puts(seq,
2150                          "  sl  "
2151                          "local_address                         "
2152                          "remote_address                        "
2153                          "st tx_queue rx_queue tr tm->when retrnsmt"
2154                          "   uid  timeout inode\n");
2155                 goto out;
2156         }
2157         st = seq->private;
2158
2159         switch (st->state) {
2160         case TCP_SEQ_STATE_LISTENING:
2161         case TCP_SEQ_STATE_ESTABLISHED:
2162                 get_tcp6_sock(seq, v, st->num);
2163                 break;
2164         case TCP_SEQ_STATE_OPENREQ:
2165                 get_openreq6(seq, st->syn_wait_sk, v, st->num, st->uid);
2166                 break;
2167         case TCP_SEQ_STATE_TIME_WAIT:
2168                 get_timewait6_sock(seq, v, st->num);
2169                 break;
2170         }
2171 out:
2172         return 0;
2173 }
2174
2175 static struct tcp_seq_afinfo tcp6_seq_afinfo = {
2176         .name           = "tcp6",
2177         .family         = AF_INET6,
2178         .seq_fops       = {
2179                 .owner          = THIS_MODULE,
2180         },
2181         .seq_ops        = {
2182                 .show           = tcp6_seq_show,
2183         },
2184 };
2185
2186 int __net_init tcp6_proc_init(struct net *net)
2187 {
2188         return tcp_proc_register(net, &tcp6_seq_afinfo);
2189 }
2190
2191 void tcp6_proc_exit(struct net *net)
2192 {
2193         tcp_proc_unregister(net, &tcp6_seq_afinfo);
2194 }
2195 #endif
2196
2197 struct proto tcpv6_prot = {
2198         .name                   = "TCPv6",
2199         .owner                  = THIS_MODULE,
2200         .close                  = tcp_close,
2201         .connect                = tcp_v6_connect,
2202         .disconnect             = tcp_disconnect,
2203         .accept                 = inet_csk_accept,
2204         .ioctl                  = tcp_ioctl,
2205         .init                   = tcp_v6_init_sock,
2206         .destroy                = tcp_v6_destroy_sock,
2207         .shutdown               = tcp_shutdown,
2208         .setsockopt             = tcp_setsockopt,
2209         .getsockopt             = tcp_getsockopt,
2210         .recvmsg                = tcp_recvmsg,
2211         .sendmsg                = tcp_sendmsg,
2212         .sendpage               = tcp_sendpage,
2213         .backlog_rcv            = tcp_v6_do_rcv,
2214         .hash                   = tcp_v6_hash,
2215         .unhash                 = inet_unhash,
2216         .get_port               = inet_csk_get_port,
2217         .enter_memory_pressure  = tcp_enter_memory_pressure,
2218         .sockets_allocated      = &tcp_sockets_allocated,
2219         .memory_allocated       = &tcp_memory_allocated,
2220         .memory_pressure        = &tcp_memory_pressure,
2221         .orphan_count           = &tcp_orphan_count,
2222         .sysctl_mem             = sysctl_tcp_mem,
2223         .sysctl_wmem            = sysctl_tcp_wmem,
2224         .sysctl_rmem            = sysctl_tcp_rmem,
2225         .max_header             = MAX_TCP_HEADER,
2226         .obj_size               = sizeof(struct tcp6_sock),
2227         .slab_flags             = SLAB_DESTROY_BY_RCU,
2228         .twsk_prot              = &tcp6_timewait_sock_ops,
2229         .rsk_prot               = &tcp6_request_sock_ops,
2230         .h.hashinfo             = &tcp_hashinfo,
2231         .no_autobind            = true,
2232 #ifdef CONFIG_COMPAT
2233         .compat_setsockopt      = compat_tcp_setsockopt,
2234         .compat_getsockopt      = compat_tcp_getsockopt,
2235 #endif
2236 };
2237
2238 static const struct inet6_protocol tcpv6_protocol = {
2239         .handler        =       tcp_v6_rcv,
2240         .err_handler    =       tcp_v6_err,
2241         .gso_send_check =       tcp_v6_gso_send_check,
2242         .gso_segment    =       tcp_tso_segment,
2243         .gro_receive    =       tcp6_gro_receive,
2244         .gro_complete   =       tcp6_gro_complete,
2245         .flags          =       INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
2246 };
2247
2248 static struct inet_protosw tcpv6_protosw = {
2249         .type           =       SOCK_STREAM,
2250         .protocol       =       IPPROTO_TCP,
2251         .prot           =       &tcpv6_prot,
2252         .ops            =       &inet6_stream_ops,
2253         .no_check       =       0,
2254         .flags          =       INET_PROTOSW_PERMANENT |
2255                                 INET_PROTOSW_ICSK,
2256 };
2257
2258 static int __net_init tcpv6_net_init(struct net *net)
2259 {
2260         return inet_ctl_sock_create(&net->ipv6.tcp_sk, PF_INET6,
2261                                     SOCK_RAW, IPPROTO_TCP, net);
2262 }
2263
2264 static void __net_exit tcpv6_net_exit(struct net *net)
2265 {
2266         inet_ctl_sock_destroy(net->ipv6.tcp_sk);
2267 }
2268
2269 static void __net_exit tcpv6_net_exit_batch(struct list_head *net_exit_list)
2270 {
2271         inet_twsk_purge(&tcp_hashinfo, &tcp_death_row, AF_INET6);
2272 }
2273
2274 static struct pernet_operations tcpv6_net_ops = {
2275         .init       = tcpv6_net_init,
2276         .exit       = tcpv6_net_exit,
2277         .exit_batch = tcpv6_net_exit_batch,
2278 };
2279
2280 int __init tcpv6_init(void)
2281 {
2282         int ret;
2283
2284         ret = inet6_add_protocol(&tcpv6_protocol, IPPROTO_TCP);
2285         if (ret)
2286                 goto out;
2287
2288         /* register inet6 protocol */
2289         ret = inet6_register_protosw(&tcpv6_protosw);
2290         if (ret)
2291                 goto out_tcpv6_protocol;
2292
2293         ret = register_pernet_subsys(&tcpv6_net_ops);
2294         if (ret)
2295                 goto out_tcpv6_protosw;
2296 out:
2297         return ret;
2298
2299 out_tcpv6_protocol:
2300         inet6_del_protocol(&tcpv6_protocol, IPPROTO_TCP);
2301 out_tcpv6_protosw:
2302         inet6_unregister_protosw(&tcpv6_protosw);
2303         goto out;
2304 }
2305
2306 void tcpv6_exit(void)
2307 {
2308         unregister_pernet_subsys(&tcpv6_net_ops);
2309         inet6_unregister_protosw(&tcpv6_protosw);
2310         inet6_del_protocol(&tcpv6_protocol, IPPROTO_TCP);
2311 }