net/dccp/ipv4.c

   1 /*
   2  *  net/dccp/ipv4.c
   3  *
   4  *  An implementation of the DCCP protocol
   5  *  Arnaldo Carvalho de Melo <acme@conectiva.com.br>
   6  *
   7  *      This program is free software; you can redistribute it and/or
   8  *      modify it under the terms of the GNU General Public License
   9  *      as published by the Free Software Foundation; either version
  10  *      2 of the License, or (at your option) any later version.
  11  */
  12
  13 #include <linux/config.h>
  14 #include <linux/dccp.h>
  15 #include <linux/icmp.h>
  16 #include <linux/module.h>
  17 #include <linux/skbuff.h>
  18 #include <linux/random.h>
  19
  20 #include <net/icmp.h>
  21 #include <net/inet_hashtables.h>
  22 #include <net/sock.h>
  23 #include <net/tcp_states.h>
  24 #include <net/xfrm.h>
  25
  26 #include "ccid.h"
  27 #include "dccp.h"
  28
  29 struct inet_hashinfo __cacheline_aligned dccp_hashinfo = {
  30         .lhash_lock     = RW_LOCK_UNLOCKED,
  31         .lhash_users    = ATOMIC_INIT(0),
  32         .lhash_wait = __WAIT_QUEUE_HEAD_INITIALIZER(dccp_hashinfo.lhash_wait),
  33         .portalloc_lock = SPIN_LOCK_UNLOCKED,
  34         .port_rover     = 1024 - 1,
  35 };
  36
  37 EXPORT_SYMBOL_GPL(dccp_hashinfo);
  38
  39 static int dccp_v4_get_port(struct sock *sk, const unsigned short snum)
  40 {
  41         return inet_csk_get_port(&dccp_hashinfo, sk, snum);
  42 }
  43
  44 static void dccp_v4_hash(struct sock *sk)
  45 {
  46         inet_hash(&dccp_hashinfo, sk);
  47 }
  48
  49 static void dccp_v4_unhash(struct sock *sk)
  50 {
  51         inet_unhash(&dccp_hashinfo, sk);
  52 }
  53
  54 /* called with local bh disabled */
  55 static int __dccp_v4_check_established(struct sock *sk, const __u16 lport,
  56                                       struct inet_timewait_sock **twp)
  57 {
  58         struct inet_sock *inet = inet_sk(sk);
  59         const u32 daddr = inet->rcv_saddr;
  60         const u32 saddr = inet->daddr;
  61         const int dif = sk->sk_bound_dev_if;
  62         INET_ADDR_COOKIE(acookie, saddr, daddr)
  63         const __u32 ports = INET_COMBINED_PORTS(inet->dport, lport);
  64         const int hash = inet_ehashfn(daddr, lport, saddr, inet->dport,
  65                                       dccp_hashinfo.ehash_size);
  66         struct inet_ehash_bucket *head = &dccp_hashinfo.ehash[hash];
  67         const struct sock *sk2;
  68         const struct hlist_node *node;
  69         struct inet_timewait_sock *tw;
  70
  71         write_lock(&head->lock);
  72
  73         /* Check TIME-WAIT sockets first. */
  74         sk_for_each(sk2, node, &(head + dccp_hashinfo.ehash_size)->chain) {
  75                 tw = inet_twsk(sk2);
  76
  77                 if (INET_TW_MATCH(sk2, acookie, saddr, daddr, ports, dif))
  78                         goto not_unique;
  79         }
  80         tw = NULL;
  81
  82         /* And established part... */
  83         sk_for_each(sk2, node, &head->chain) {
  84                 if (INET_MATCH(sk2, acookie, saddr, daddr, ports, dif))
  85                         goto not_unique;
  86         }
  87
  88         /* Must record num and sport now. Otherwise we will see
  89          * in hash table socket with a funny identity. */
  90         inet->num = lport;
  91         inet->sport = htons(lport);
  92         sk->sk_hashent = hash;
  93         BUG_TRAP(sk_unhashed(sk));
  94         __sk_add_node(sk, &head->chain);
  95         sock_prot_inc_use(sk->sk_prot);
  96         write_unlock(&head->lock);
  97
  98         if (twp != NULL) {
  99                 *twp = tw;
 100                 NET_INC_STATS_BH(LINUX_MIB_TIMEWAITRECYCLED);
 101         } else if (tw != NULL) {
 102                 /* Silly. Should hash-dance instead... */
 103                 inet_twsk_deschedule(tw, &dccp_death_row);
 104                 NET_INC_STATS_BH(LINUX_MIB_TIMEWAITRECYCLED);
 105
 106                 inet_twsk_put(tw);
 107         }
 108
 109         return 0;
 110
 111 not_unique:
 112         write_unlock(&head->lock);
 113         return -EADDRNOTAVAIL;
 114 }
 115
 116 /*
 117  * Bind a port for a connect operation and hash it.
 118  */
 119 static int dccp_v4_hash_connect(struct sock *sk)
 120 {
 121         const unsigned short snum = inet_sk(sk)->num;
 122         struct inet_bind_hashbucket *head;
 123         struct inet_bind_bucket *tb;
 124         int ret;
 125
 126         if (snum == 0) {
 127                 int rover;
 128                 int low = sysctl_local_port_range[0];
 129                 int high = sysctl_local_port_range[1];
 130                 int remaining = (high - low) + 1;
 131                 struct hlist_node *node;
 132                 struct inet_timewait_sock *tw = NULL;
 133
 134                 local_bh_disable();
 135
 136                 /* TODO. Actually it is not so bad idea to remove
 137                  * dccp_hashinfo.portalloc_lock before next submission to
 138                  * Linus.
 139                  * As soon as we touch this place at all it is time to think.
 140                  *
 141                  * Now it protects single _advisory_ variable
 142                  * dccp_hashinfo.port_rover, hence it is mostly useless.
 143                  * Code will work nicely if we just delete it, but
 144                  * I am afraid in contented case it will work not better or
 145                  * even worse: another cpu just will hit the same bucket
 146                  * and spin there.
 147                  * So some cpu salt could remove both contention and
 148                  * memory pingpong. Any ideas how to do this in a nice way?
 149                  */
 150                 spin_lock(&dccp_hashinfo.portalloc_lock);
 151                 rover = dccp_hashinfo.port_rover;
 152
 153                 do {
 154                         rover++;
 155                         if ((rover < low) || (rover > high))
 156                                 rover = low;
 157                         head = &dccp_hashinfo.bhash[inet_bhashfn(rover,
 158                                                     dccp_hashinfo.bhash_size)];
 159                         spin_lock(&head->lock);
 160
 161                         /* Does not bother with rcv_saddr checks,
 162                          * because the established check is already
 163                          * unique enough.
 164                          */
 165                         inet_bind_bucket_for_each(tb, node, &head->chain) {
 166                                 if (tb->port == rover) {
 167                                         BUG_TRAP(!hlist_empty(&tb->owners));
 168                                         if (tb->fastreuse >= 0)
 169                                                 goto next_port;
 170                                         if (!__dccp_v4_check_established(sk,
 171                                                                          rover,
 172                                                                          &tw))
 173                                                 goto ok;
 174                                         goto next_port;
 175                                 }
 176                         }
 177
 178                         tb = inet_bind_bucket_create(dccp_hashinfo.bind_bucket_cachep,
 179                                                      head, rover);
 180                         if (tb == NULL) {
 181                                 spin_unlock(&head->lock);
 182                                 break;
 183                         }
 184                         tb->fastreuse = -1;
 185                         goto ok;
 186
 187                 next_port:
 188                         spin_unlock(&head->lock);
 189                 } while (--remaining > 0);
 190                 dccp_hashinfo.port_rover = rover;
 191                 spin_unlock(&dccp_hashinfo.portalloc_lock);
 192
 193                 local_bh_enable();
 194
 195                 return -EADDRNOTAVAIL;
 196
 197 ok:
 198                 /* All locks still held and bhs disabled */
 199                 dccp_hashinfo.port_rover = rover;
 200                 spin_unlock(&dccp_hashinfo.portalloc_lock);
 201
 202                 inet_bind_hash(sk, tb, rover);
 203                 if (sk_unhashed(sk)) {
 204                         inet_sk(sk)->sport = htons(rover);
 205                         __inet_hash(&dccp_hashinfo, sk, 0);
 206                 }
 207                 spin_unlock(&head->lock);
 208
 209                 if (tw != NULL) {
 210                         inet_twsk_deschedule(tw, &dccp_death_row);
 211                         inet_twsk_put(tw);
 212                 }
 213
 214                 ret = 0;
 215                 goto out;
 216         }
 217
 218         head = &dccp_hashinfo.bhash[inet_bhashfn(snum,
 219                                                  dccp_hashinfo.bhash_size)];
 220         tb   = inet_csk(sk)->icsk_bind_hash;
 221         spin_lock_bh(&head->lock);
 222         if (sk_head(&tb->owners) == sk && sk->sk_bind_node.next == NULL) {
 223                 __inet_hash(&dccp_hashinfo, sk, 0);
 224                 spin_unlock_bh(&head->lock);
 225                 return 0;
 226         } else {
 227                 spin_unlock(&head->lock);
 228                 /* No definite answer... Walk to established hash table */
 229                 ret = __dccp_v4_check_established(sk, snum, NULL);
 230 out:
 231                 local_bh_enable();
 232                 return ret;
 233         }
 234 }
 235
 236 static int dccp_v4_connect(struct sock *sk, struct sockaddr *uaddr,
 237                            int addr_len)
 238 {
 239         struct inet_sock *inet = inet_sk(sk);
 240         struct dccp_sock *dp = dccp_sk(sk);
 241         const struct sockaddr_in *usin = (struct sockaddr_in *)uaddr;
 242         struct rtable *rt;
 243         u32 daddr, nexthop;
 244         int tmp;
 245         int err;
 246
 247         dp->dccps_role = DCCP_ROLE_CLIENT;
 248
 249         if (addr_len < sizeof(struct sockaddr_in))
 250                 return -EINVAL;
 251
 252         if (usin->sin_family != AF_INET)
 253                 return -EAFNOSUPPORT;
 254
 255         nexthop = daddr = usin->sin_addr.s_addr;
 256         if (inet->opt != NULL && inet->opt->srr) {
 257                 if (daddr == 0)
 258                         return -EINVAL;
 259                 nexthop = inet->opt->faddr;
 260         }
 261
 262         tmp = ip_route_connect(&rt, nexthop, inet->saddr,
 263                                RT_CONN_FLAGS(sk), sk->sk_bound_dev_if,
 264                                IPPROTO_DCCP,
 265                                inet->sport, usin->sin_port, sk);
 266         if (tmp < 0)
 267                 return tmp;
 268
 269         if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) {
 270                 ip_rt_put(rt);
 271                 return -ENETUNREACH;
 272         }
 273
 274         if (inet->opt == NULL || !inet->opt->srr)
 275                 daddr = rt->rt_dst;
 276
 277         if (inet->saddr == 0)
 278                 inet->saddr = rt->rt_src;
 279         inet->rcv_saddr = inet->saddr;
 280
 281         inet->dport = usin->sin_port;
 282         inet->daddr = daddr;
 283
 284         dp->dccps_ext_header_len = 0;
 285         if (inet->opt != NULL)
 286                 dp->dccps_ext_header_len = inet->opt->optlen;
 287         /*
 288          * Socket identity is still unknown (sport may be zero).
 289          * However we set state to DCCP_REQUESTING and not releasing socket
 290          * lock select source port, enter ourselves into the hash tables and
 291          * complete initialization after this.
 292          */
 293         dccp_set_state(sk, DCCP_REQUESTING);
 294         err = dccp_v4_hash_connect(sk);
 295         if (err != 0)
 296                 goto failure;
 297
 298         err = ip_route_newports(&rt, inet->sport, inet->dport, sk);
 299         if (err != 0)
 300                 goto failure;
 301
 302         /* OK, now commit destination to socket.  */
 303         sk_setup_caps(sk, &rt->u.dst);
 304
 305         dp->dccps_gar =
 306                 dp->dccps_iss = secure_dccp_sequence_number(inet->saddr,
 307                                                             inet->daddr,
 308                                                             inet->sport,
 309                                                             usin->sin_port);
 310         dccp_update_gss(sk, dp->dccps_iss);
 311
 312         /*
 313          * SWL and AWL are initially adjusted so that they are not less than
 314          * the initial Sequence Numbers received and sent, respectively:
 315          *      SWL := max(GSR + 1 - floor(W/4), ISR),
 316          *      AWL := max(GSS - W' + 1, ISS).
 317          * These adjustments MUST be applied only at the beginning of the
 318          * connection.
 319          */
 320         dccp_set_seqno(&dp->dccps_awl, max48(dp->dccps_awl, dp->dccps_iss));
 321
 322         inet->id = dp->dccps_iss ^ jiffies;
 323
 324         err = dccp_connect(sk);
 325         rt = NULL;
 326         if (err != 0)
 327                 goto failure;
 328 out:
 329         return err;
 330 failure:
 331         /*
 332          * This unhashes the socket and releases the local port, if necessary.
 333          */
 334         dccp_set_state(sk, DCCP_CLOSED);
 335         ip_rt_put(rt);
 336         sk->sk_route_caps = 0;
 337         inet->dport = 0;
 338         goto out;
 339 }
 340
 341 /*
 342  * This routine does path mtu discovery as defined in RFC1191.
 343  */
 344 static inline void dccp_do_pmtu_discovery(struct sock *sk,
 345                                           const struct iphdr *iph,
 346                                           u32 mtu)
 347 {
 348         struct dst_entry *dst;
 349         const struct inet_sock *inet = inet_sk(sk);
 350         const struct dccp_sock *dp = dccp_sk(sk);
 351
 352         /* We are not interested in DCCP_LISTEN and request_socks (RESPONSEs
 353          * send out by Linux are always < 576bytes so they should go through
 354          * unfragmented).
 355          */
 356         if (sk->sk_state == DCCP_LISTEN)
 357                 return;
 358
 359         /* We don't check in the destentry if pmtu discovery is forbidden
 360          * on this route. We just assume that no packet_to_big packets
 361          * are send back when pmtu discovery is not active.
 362          * There is a small race when the user changes this flag in the
 363          * route, but I think that's acceptable.
 364          */
 365         if ((dst = __sk_dst_check(sk, 0)) == NULL)
 366                 return;
 367
 368         dst->ops->update_pmtu(dst, mtu);
 369
 370         /* Something is about to be wrong... Remember soft error
 371          * for the case, if this connection will not able to recover.
 372          */
 373         if (mtu < dst_mtu(dst) && ip_dont_fragment(sk, dst))
 374                 sk->sk_err_soft = EMSGSIZE;
 375
 376         mtu = dst_mtu(dst);
 377
 378         if (inet->pmtudisc != IP_PMTUDISC_DONT &&
 379             dp->dccps_pmtu_cookie > mtu) {
 380                 dccp_sync_mss(sk, mtu);
 381
 382                 /*
 383                  * From: draft-ietf-dccp-spec-11.txt
 384                  *
 385                  *      DCCP-Sync packets are the best choice for upward
 386                  *      probing, since DCCP-Sync probes do not risk application
 387                  *      data loss.
 388                  */
 389                 dccp_send_sync(sk, dp->dccps_gsr, DCCP_PKT_SYNC);
 390         } /* else let the usual retransmit timer handle it */
 391 }
 392
 393 static void dccp_v4_ctl_send_ack(struct sk_buff *rxskb)
 394 {
 395         int err;
 396         struct dccp_hdr *rxdh = dccp_hdr(rxskb), *dh;
 397         const int dccp_hdr_ack_len = sizeof(struct dccp_hdr) +
 398                                      sizeof(struct dccp_hdr_ext) +
 399                                      sizeof(struct dccp_hdr_ack_bits);
 400         struct sk_buff *skb;
 401
 402         if (((struct rtable *)rxskb->dst)->rt_type != RTN_LOCAL)
 403                 return;
 404
 405         skb = alloc_skb(MAX_DCCP_HEADER + 15, GFP_ATOMIC);
 406         if (skb == NULL)
 407                 return;
 408
 409         /* Reserve space for headers. */
 410         skb_reserve(skb, MAX_DCCP_HEADER);
 411
 412         skb->dst = dst_clone(rxskb->dst);
 413
 414         skb->h.raw = skb_push(skb, dccp_hdr_ack_len);
 415         dh = dccp_hdr(skb);
 416         memset(dh, 0, dccp_hdr_ack_len);
 417
 418         /* Build DCCP header and checksum it. */
 419         dh->dccph_type     = DCCP_PKT_ACK;
 420         dh->dccph_sport    = rxdh->dccph_dport;
 421         dh->dccph_dport    = rxdh->dccph_sport;
 422         dh->dccph_doff     = dccp_hdr_ack_len / 4;
 423         dh->dccph_x        = 1;
 424
 425         dccp_hdr_set_seq(dh, DCCP_SKB_CB(rxskb)->dccpd_ack_seq);
 426         dccp_hdr_set_ack(dccp_hdr_ack_bits(skb),
 427                          DCCP_SKB_CB(rxskb)->dccpd_seq);
 428
 429         bh_lock_sock(dccp_ctl_socket->sk);
 430         err = ip_build_and_send_pkt(skb, dccp_ctl_socket->sk,
 431                                     rxskb->nh.iph->daddr,
 432                                     rxskb->nh.iph->saddr, NULL);
 433         bh_unlock_sock(dccp_ctl_socket->sk);
 434
 435         if (err == NET_XMIT_CN || err == 0) {
 436                 DCCP_INC_STATS_BH(DCCP_MIB_OUTSEGS);
 437                 DCCP_INC_STATS_BH(DCCP_MIB_OUTRSTS);
 438         }
 439 }
 440
 441 static void dccp_v4_reqsk_send_ack(struct sk_buff *skb,
 442                                    struct request_sock *req)
 443 {
 444         dccp_v4_ctl_send_ack(skb);
 445 }
 446
 447 static int dccp_v4_send_response(struct sock *sk, struct request_sock *req,
 448                                  struct dst_entry *dst)
 449 {
 450         int err = -1;
 451         struct sk_buff *skb;
 452
 453         /* First, grab a route. */
 454
 455         if (dst == NULL && (dst = inet_csk_route_req(sk, req)) == NULL)
 456                 goto out;
 457
 458         skb = dccp_make_response(sk, dst, req);
 459         if (skb != NULL) {
 460                 const struct inet_request_sock *ireq = inet_rsk(req);
 461
 462                 err = ip_build_and_send_pkt(skb, sk, ireq->loc_addr,
 463                                             ireq->rmt_addr,
 464                                             ireq->opt);
 465                 if (err == NET_XMIT_CN)
 466                         err = 0;
 467         }
 468
 469 out:
 470         dst_release(dst);
 471         return err;
 472 }
 473
 474 /*
 475  * This routine is called by the ICMP module when it gets some sort of error
 476  * condition. If err < 0 then the socket should be closed and the error
 477  * returned to the user. If err > 0 it's just the icmp type << 8 | icmp code.
 478  * After adjustment header points to the first 8 bytes of the tcp header. We
 479  * need to find the appropriate port.
 480  *
 481  * The locking strategy used here is very "optimistic". When someone else
 482  * accesses the socket the ICMP is just dropped and for some paths there is no
 483  * check at all. A more general error queue to queue errors for later handling
 484  * is probably better.
 485  */
 486 void dccp_v4_err(struct sk_buff *skb, u32 info)
 487 {
 488         const struct iphdr *iph = (struct iphdr *)skb->data;
 489         const struct dccp_hdr *dh = (struct dccp_hdr *)(skb->data +
 490                                                         (iph->ihl << 2));
 491         struct dccp_sock *dp;
 492         struct inet_sock *inet;
 493         const int type = skb->h.icmph->type;
 494         const int code = skb->h.icmph->code;
 495         struct sock *sk;
 496         __u64 seq;
 497         int err;
 498
 499         if (skb->len < (iph->ihl << 2) + 8) {
 500                 ICMP_INC_STATS_BH(ICMP_MIB_INERRORS);
 501                 return;
 502         }
 503
 504         sk = inet_lookup(&dccp_hashinfo, iph->daddr, dh->dccph_dport,
 505                          iph->saddr, dh->dccph_sport, inet_iif(skb));
 506         if (sk == NULL) {
 507                 ICMP_INC_STATS_BH(ICMP_MIB_INERRORS);
 508                 return;
 509         }
 510
 511         if (sk->sk_state == DCCP_TIME_WAIT) {
 512                 inet_twsk_put((struct inet_timewait_sock *)sk);
 513                 return;
 514         }
 515
 516         bh_lock_sock(sk);
 517         /* If too many ICMPs get dropped on busy
 518          * servers this needs to be solved differently.
 519          */
 520         if (sock_owned_by_user(sk))
 521                 NET_INC_STATS_BH(LINUX_MIB_LOCKDROPPEDICMPS);
 522
 523         if (sk->sk_state == DCCP_CLOSED)
 524                 goto out;
 525
 526         dp = dccp_sk(sk);
 527         seq = dccp_hdr_seq(skb);
 528         if (sk->sk_state != DCCP_LISTEN &&
 529             !between48(seq, dp->dccps_swl, dp->dccps_swh)) {
 530                 NET_INC_STATS(LINUX_MIB_OUTOFWINDOWICMPS);
 531                 goto out;
 532         }
 533
 534         switch (type) {
 535         case ICMP_SOURCE_QUENCH:
 536                 /* Just silently ignore these. */
 537                 goto out;
 538         case ICMP_PARAMETERPROB:
 539                 err = EPROTO;
 540                 break;
 541         case ICMP_DEST_UNREACH:
 542                 if (code > NR_ICMP_UNREACH)
 543                         goto out;
 544
 545                 if (code == ICMP_FRAG_NEEDED) { /* PMTU discovery (RFC1191) */
 546                         if (!sock_owned_by_user(sk))
 547                                 dccp_do_pmtu_discovery(sk, iph, info);
 548                         goto out;
 549                 }
 550
 551                 err = icmp_err_convert[code].errno;
 552                 break;
 553         case ICMP_TIME_EXCEEDED:
 554                 err = EHOSTUNREACH;
 555                 break;
 556         default:
 557                 goto out;
 558         }
 559
 560         switch (sk->sk_state) {
 561                 struct request_sock *req , **prev;
 562         case DCCP_LISTEN:
 563                 if (sock_owned_by_user(sk))
 564                         goto out;
 565                 req = inet_csk_search_req(sk, &prev, dh->dccph_dport,
 566                                           iph->daddr, iph->saddr);
 567                 if (!req)
 568                         goto out;
 569
 570                 /*
 571                  * ICMPs are not backlogged, hence we cannot get an established
 572                  * socket here.
 573                  */
 574                 BUG_TRAP(!req->sk);
 575
 576                 if (seq != dccp_rsk(req)->dreq_iss) {
 577                         NET_INC_STATS_BH(LINUX_MIB_OUTOFWINDOWICMPS);
 578                         goto out;
 579                 }
 580                 /*
 581                  * Still in RESPOND, just remove it silently.
 582                  * There is no good way to pass the error to the newly
 583                  * created socket, and POSIX does not want network
 584                  * errors returned from accept().
 585                  */
 586                 inet_csk_reqsk_queue_drop(sk, req, prev);
 587                 goto out;
 588
 589         case DCCP_REQUESTING:
 590         case DCCP_RESPOND:
 591                 if (!sock_owned_by_user(sk)) {
 592                         DCCP_INC_STATS_BH(DCCP_MIB_ATTEMPTFAILS);
 593                         sk->sk_err = err;
 594
 595                         sk->sk_error_report(sk);
 596
 597                         dccp_done(sk);
 598                 } else
 599                         sk->sk_err_soft = err;
 600                 goto out;
 601         }
 602
 603         /* If we've already connected we will keep trying
 604          * until we time out, or the user gives up.
 605          *
 606          * rfc1122 4.2.3.9 allows to consider as hard errors
 607          * only PROTO_UNREACH and PORT_UNREACH (well, FRAG_FAILED too,
 608          * but it is obsoleted by pmtu discovery).
 609          *
 610          * Note, that in modern internet, where routing is unreliable
 611          * and in each dark corner broken firewalls sit, sending random
 612          * errors ordered by their masters even this two messages finally lose
 613          * their original sense (even Linux sends invalid PORT_UNREACHs)
 614          *
 615          * Now we are in compliance with RFCs.
 616          *                                                      --ANK (980905)
 617          */
 618
 619         inet = inet_sk(sk);
 620         if (!sock_owned_by_user(sk) && inet->recverr) {
 621                 sk->sk_err = err;
 622                 sk->sk_error_report(sk);
 623         } else /* Only an error on timeout */
 624                 sk->sk_err_soft = err;
 625 out:
 626         bh_unlock_sock(sk);
 627         sock_put(sk);
 628 }
 629
 630 int dccp_v4_send_reset(struct sock *sk, enum dccp_reset_codes code)
 631 {
 632         struct sk_buff *skb;
 633         /*
 634          * FIXME: what if rebuild_header fails?
 635          * Should we be doing a rebuild_header here?
 636          */
 637         int err = inet_sk_rebuild_header(sk);
 638
 639         if (err != 0)
 640                 return err;
 641
 642         skb = dccp_make_reset(sk, sk->sk_dst_cache, code);
 643         if (skb != NULL) {
 644                 const struct dccp_sock *dp = dccp_sk(sk);
 645                 const struct inet_sock *inet = inet_sk(sk);
 646
 647                 err = ip_build_and_send_pkt(skb, sk,
 648                                             inet->saddr, inet->daddr, NULL);
 649                 if (err == NET_XMIT_CN)
 650                         err = 0;
 651
 652                 ccid_hc_rx_exit(dp->dccps_hc_rx_ccid, sk);
 653                 ccid_hc_tx_exit(dp->dccps_hc_tx_ccid, sk);
 654         }
 655
 656         return err;
 657 }
 658
 659 static inline u64 dccp_v4_init_sequence(const struct sock *sk,
 660                                         const struct sk_buff *skb)
 661 {
 662         return secure_dccp_sequence_number(skb->nh.iph->daddr,
 663                                            skb->nh.iph->saddr,
 664                                            dccp_hdr(skb)->dccph_dport,
 665                                            dccp_hdr(skb)->dccph_sport);
 666 }
 667
 668 int dccp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
 669 {
 670         struct inet_request_sock *ireq;
 671         struct dccp_sock dp;
 672         struct request_sock *req;
 673         struct dccp_request_sock *dreq;
 674         const __u32 saddr = skb->nh.iph->saddr;
 675         const __u32 daddr = skb->nh.iph->daddr;
 676         struct dst_entry *dst = NULL;
 677
 678         /* Never answer to DCCP_PKT_REQUESTs send to broadcast or multicast */
 679         if (((struct rtable *)skb->dst)->rt_flags &
 680             (RTCF_BROADCAST | RTCF_MULTICAST))
 681                 goto drop;
 682
 683         /*
 684          * TW buckets are converted to open requests without
 685          * limitations, they conserve resources and peer is
 686          * evidently real one.
 687          */
 688         if (inet_csk_reqsk_queue_is_full(sk))
 689                 goto drop;
 690
 691         /*
 692          * Accept backlog is full. If we have already queued enough
 693          * of warm entries in syn queue, drop request. It is better than
 694          * clogging syn queue with openreqs with exponentially increasing
 695          * timeout.
 696          */
 697         if (sk_acceptq_is_full(sk) && inet_csk_reqsk_queue_young(sk) > 1)
 698                 goto drop;
 699
 700         req = reqsk_alloc(sk->sk_prot->rsk_prot);
 701         if (req == NULL)
 702                 goto drop;
 703
 704         /* FIXME: process options */
 705
 706         dccp_openreq_init(req, &dp, skb);
 707
 708         ireq = inet_rsk(req);
 709         ireq->loc_addr = daddr;
 710         ireq->rmt_addr = saddr;
 711         /* FIXME: Merge Aristeu's option parsing code when ready */
 712         req->rcv_wnd    = 100; /* Fake, option parsing will get the
 713                                   right value */
 714         ireq->opt       = NULL;
 715
 716         /*
 717          * Step 3: Process LISTEN state
 718          *
 719          * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookie
 720          *
 721          * In fact we defer setting S.GSR, S.SWL, S.SWH to
 722          * dccp_create_openreq_child.
 723          */
 724         dreq = dccp_rsk(req);
 725         dreq->dreq_isr = DCCP_SKB_CB(skb)->dccpd_seq;
 726         dreq->dreq_iss = dccp_v4_init_sequence(sk, skb);
 727         dreq->dreq_service = dccp_hdr_request(skb)->dccph_req_service;
 728
 729         if (dccp_v4_send_response(sk, req, dst))
 730                 goto drop_and_free;
 731
 732         inet_csk_reqsk_queue_hash_add(sk, req, DCCP_TIMEOUT_INIT);
 733         return 0;
 734
 735 drop_and_free:
 736         /*
 737          * FIXME: should be reqsk_free after implementing req->rsk_ops
 738          */
 739         __reqsk_free(req);
 740 drop:
 741         DCCP_INC_STATS_BH(DCCP_MIB_ATTEMPTFAILS);
 742         return -1;
 743 }
 744
 745 /*
 746  * The three way handshake has completed - we got a valid ACK or DATAACK -
 747  * now create the new socket.
 748  *
 749  * This is the equivalent of TCP's tcp_v4_syn_recv_sock
 750  */
 751 struct sock *dccp_v4_request_recv_sock(struct sock *sk, struct sk_buff *skb,
 752                                        struct request_sock *req,
 753                                        struct dst_entry *dst)
 754 {
 755         struct inet_request_sock *ireq;
 756         struct inet_sock *newinet;
 757         struct dccp_sock *newdp;
 758         struct sock *newsk;
 759
 760         if (sk_acceptq_is_full(sk))
 761                 goto exit_overflow;
 762
 763         if (dst == NULL && (dst = inet_csk_route_req(sk, req)) == NULL)
 764                 goto exit;
 765
 766         newsk = dccp_create_openreq_child(sk, req, skb);
 767         if (newsk == NULL)
 768                 goto exit;
 769
 770         sk_setup_caps(newsk, dst);
 771
 772         newdp              = dccp_sk(newsk);
 773         newinet            = inet_sk(newsk);
 774         ireq               = inet_rsk(req);
 775         newinet->daddr     = ireq->rmt_addr;
 776         newinet->rcv_saddr = ireq->loc_addr;
 777         newinet->saddr     = ireq->loc_addr;
 778         newinet->opt       = ireq->opt;
 779         ireq->opt          = NULL;
 780         newinet->mc_index  = inet_iif(skb);
 781         newinet->mc_ttl    = skb->nh.iph->ttl;
 782         newinet->id        = jiffies;
 783
 784         dccp_sync_mss(newsk, dst_mtu(dst));
 785
 786         __inet_hash(&dccp_hashinfo, newsk, 0);
 787         __inet_inherit_port(&dccp_hashinfo, sk, newsk);
 788
 789         return newsk;
 790
 791 exit_overflow:
 792         NET_INC_STATS_BH(LINUX_MIB_LISTENOVERFLOWS);
 793 exit:
 794         NET_INC_STATS_BH(LINUX_MIB_LISTENDROPS);
 795         dst_release(dst);
 796         return NULL;
 797 }
 798
 799 static struct sock *dccp_v4_hnd_req(struct sock *sk, struct sk_buff *skb)
 800 {
 801         const struct dccp_hdr *dh = dccp_hdr(skb);
 802         const struct iphdr *iph = skb->nh.iph;
 803         struct sock *nsk;
 804         struct request_sock **prev;
 805         /* Find possible connection requests. */
 806         struct request_sock *req = inet_csk_search_req(sk, &prev,
 807                                                        dh->dccph_sport,
 808                                                        iph->saddr, iph->daddr);
 809         if (req != NULL)
 810                 return dccp_check_req(sk, skb, req, prev);
 811
 812         nsk = __inet_lookup_established(&dccp_hashinfo,
 813                                         iph->saddr, dh->dccph_sport,
 814                                         iph->daddr, ntohs(dh->dccph_dport),
 815                                         inet_iif(skb));
 816         if (nsk != NULL) {
 817                 if (nsk->sk_state != DCCP_TIME_WAIT) {
 818                         bh_lock_sock(nsk);
 819                         return nsk;
 820                 }
 821                 inet_twsk_put((struct inet_timewait_sock *)nsk);
 822                 return NULL;
 823         }
 824
 825         return sk;
 826 }
 827
 828 int dccp_v4_checksum(const struct sk_buff *skb, const u32 saddr,
 829                      const u32 daddr)
 830 {
 831         const struct dccp_hdr* dh = dccp_hdr(skb);
 832         int checksum_len;
 833         u32 tmp;
 834
 835         if (dh->dccph_cscov == 0)
 836                 checksum_len = skb->len;
 837         else {
 838                 checksum_len = (dh->dccph_cscov + dh->dccph_x) * sizeof(u32);
 839                 checksum_len = checksum_len < skb->len ? checksum_len :
 840                                                          skb->len;
 841         }
 842
 843         tmp = csum_partial((unsigned char *)dh, checksum_len, 0);
 844         return csum_tcpudp_magic(saddr, daddr, checksum_len,
 845                                  IPPROTO_DCCP, tmp);
 846 }
 847
 848 static int dccp_v4_verify_checksum(struct sk_buff *skb,
 849                                    const u32 saddr, const u32 daddr)
 850 {
 851         struct dccp_hdr *dh = dccp_hdr(skb);
 852         int checksum_len;
 853         u32 tmp;
 854
 855         if (dh->dccph_cscov == 0)
 856                 checksum_len = skb->len;
 857         else {
 858                 checksum_len = (dh->dccph_cscov + dh->dccph_x) * sizeof(u32);
 859                 checksum_len = checksum_len < skb->len ? checksum_len :
 860                                                          skb->len;
 861         }
 862         tmp = csum_partial((unsigned char *)dh, checksum_len, 0);
 863         return csum_tcpudp_magic(saddr, daddr, checksum_len,
 864                                  IPPROTO_DCCP, tmp) == 0 ? 0 : -1;
 865 }
 866
 867 static struct dst_entry* dccp_v4_route_skb(struct sock *sk,
 868                                            struct sk_buff *skb)
 869 {
 870         struct rtable *rt;
 871         struct flowi fl = { .oif = ((struct rtable *)skb->dst)->rt_iif,
 872                             .nl_u = { .ip4_u =
 873                                       { .daddr = skb->nh.iph->saddr,
 874                                         .saddr = skb->nh.iph->daddr,
 875                                         .tos = RT_CONN_FLAGS(sk) } },
 876                             .proto = sk->sk_protocol,
 877                             .uli_u = { .ports =
 878                                        { .sport = dccp_hdr(skb)->dccph_dport,
 879                                          .dport = dccp_hdr(skb)->dccph_sport }
 880                                      }
 881                           };
 882
 883         if (ip_route_output_flow(&rt, &fl, sk, 0)) {
 884                 IP_INC_STATS_BH(IPSTATS_MIB_OUTNOROUTES);
 885                 return NULL;
 886         }
 887
 888         return &rt->u.dst;
 889 }
 890
 891 static void dccp_v4_ctl_send_reset(struct sk_buff *rxskb)
 892 {
 893         int err;
 894         struct dccp_hdr *rxdh = dccp_hdr(rxskb), *dh;
 895         const int dccp_hdr_reset_len = sizeof(struct dccp_hdr) +
 896                                        sizeof(struct dccp_hdr_ext) +
 897                                        sizeof(struct dccp_hdr_reset);
 898         struct sk_buff *skb;
 899         struct dst_entry *dst;
 900         u64 seqno;
 901
 902         /* Never send a reset in response to a reset. */
 903         if (rxdh->dccph_type == DCCP_PKT_RESET)
 904                 return;
 905
 906         if (((struct rtable *)rxskb->dst)->rt_type != RTN_LOCAL)
 907                 return;
 908
 909         dst = dccp_v4_route_skb(dccp_ctl_socket->sk, rxskb);
 910         if (dst == NULL)
 911                 return;
 912
 913         skb = alloc_skb(MAX_DCCP_HEADER + 15, GFP_ATOMIC);
 914         if (skb == NULL)
 915                 goto out;
 916
 917         /* Reserve space for headers. */
 918         skb_reserve(skb, MAX_DCCP_HEADER);
 919         skb->dst = dst_clone(dst);
 920
 921         skb->h.raw = skb_push(skb, dccp_hdr_reset_len);
 922         dh = dccp_hdr(skb);
 923         memset(dh, 0, dccp_hdr_reset_len);
 924
 925         /* Build DCCP header and checksum it. */
 926         dh->dccph_type     = DCCP_PKT_RESET;
 927         dh->dccph_sport    = rxdh->dccph_dport;
 928         dh->dccph_dport    = rxdh->dccph_sport;
 929         dh->dccph_doff     = dccp_hdr_reset_len / 4;
 930         dh->dccph_x        = 1;
 931         dccp_hdr_reset(skb)->dccph_reset_code =
 932                                 DCCP_SKB_CB(rxskb)->dccpd_reset_code;
 933
 934         /* See "8.3.1. Abnormal Termination" in draft-ietf-dccp-spec-11 */
 935         seqno = 0;
 936         if (DCCP_SKB_CB(rxskb)->dccpd_ack_seq != DCCP_PKT_WITHOUT_ACK_SEQ)
 937                 dccp_set_seqno(&seqno, DCCP_SKB_CB(rxskb)->dccpd_ack_seq + 1);
 938
 939         dccp_hdr_set_seq(dh, seqno);
 940         dccp_hdr_set_ack(dccp_hdr_ack_bits(skb),
 941                          DCCP_SKB_CB(rxskb)->dccpd_seq);
 942
 943         dh->dccph_checksum = dccp_v4_checksum(skb, rxskb->nh.iph->saddr,
 944                                               rxskb->nh.iph->daddr);
 945
 946         bh_lock_sock(dccp_ctl_socket->sk);
 947         err = ip_build_and_send_pkt(skb, dccp_ctl_socket->sk,
 948                                     rxskb->nh.iph->daddr,
 949                                     rxskb->nh.iph->saddr, NULL);
 950         bh_unlock_sock(dccp_ctl_socket->sk);
 951
 952         if (err == NET_XMIT_CN || err == 0) {
 953                 DCCP_INC_STATS_BH(DCCP_MIB_OUTSEGS);
 954                 DCCP_INC_STATS_BH(DCCP_MIB_OUTRSTS);
 955         }
 956 out:
 957          dst_release(dst);
 958 }
 959
 960 int dccp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
 961 {
 962         struct dccp_hdr *dh = dccp_hdr(skb);
 963
 964         if (sk->sk_state == DCCP_OPEN) { /* Fast path */
 965                 if (dccp_rcv_established(sk, skb, dh, skb->len))
 966                         goto reset;
 967                 return 0;
 968         }
 969
 970         /*
 971          *  Step 3: Process LISTEN state
 972          *     If S.state == LISTEN,
 973          *        If P.type == Request or P contains a valid Init Cookie
 974          *              option,
 975          *           * Must scan the packet's options to check for an Init
 976          *              Cookie.  Only the Init Cookie is processed here,
 977          *              however; other options are processed in Step 8.  This
 978          *              scan need only be performed if the endpoint uses Init
 979          *              Cookies *
 980          *           * Generate a new socket and switch to that socket *
 981          *           Set S := new socket for this port pair
 982          *           S.state = RESPOND
 983          *           Choose S.ISS (initial seqno) or set from Init Cookie
 984          *           Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookie
 985          *           Continue with S.state == RESPOND
 986          *           * A Response packet will be generated in Step 11 *
 987          *        Otherwise,
 988          *           Generate Reset(No Connection) unless P.type == Reset
 989          *           Drop packet and return
 990          *
 991          * NOTE: the check for the packet types is done in
 992          *       dccp_rcv_state_process
 993          */
 994         if (sk->sk_state == DCCP_LISTEN) {
 995                 struct sock *nsk = dccp_v4_hnd_req(sk, skb);
 996
 997                 if (nsk == NULL)
 998                         goto discard;
 999
1000                 if (nsk != sk) {
1001                         if (dccp_child_process(sk, nsk, skb))
1002                                 goto reset;
1003                         return 0;
1004                 }
1005         }
1006
1007         if (dccp_rcv_state_process(sk, skb, dh, skb->len))
1008                 goto reset;
1009         return 0;
1010
1011 reset:
1012         DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_NO_CONNECTION;
1013         dccp_v4_ctl_send_reset(skb);
1014 discard:
1015         kfree_skb(skb);
1016         return 0;
1017 }
1018
1019 static inline int dccp_invalid_packet(struct sk_buff *skb)
1020 {
1021         const struct dccp_hdr *dh;
1022
1023         if (skb->pkt_type != PACKET_HOST)
1024                 return 1;
1025
1026         if (!pskb_may_pull(skb, sizeof(struct dccp_hdr))) {
1027                 LIMIT_NETDEBUG(KERN_WARNING "DCCP: pskb_may_pull failed\n");
1028                 return 1;
1029         }
1030
1031         dh = dccp_hdr(skb);
1032
1033         /* If the packet type is not understood, drop packet and return */
1034         if (dh->dccph_type >= DCCP_PKT_INVALID) {
1035                 LIMIT_NETDEBUG(KERN_WARNING "DCCP: invalid packet type\n");
1036                 return 1;
1037         }
1038
1039         /*
1040          * If P.Data Offset is too small for packet type, or too large for
1041          * packet, drop packet and return
1042          */
1043         if (dh->dccph_doff < dccp_hdr_len(skb) / sizeof(u32)) {
1044                 LIMIT_NETDEBUG(KERN_WARNING "DCCP: P.Data Offset(%u) "
1045                                             "too small 1\n",
1046                                dh->dccph_doff);
1047                 return 1;
1048         }
1049
1050         if (!pskb_may_pull(skb, dh->dccph_doff * sizeof(u32))) {
1051                 LIMIT_NETDEBUG(KERN_WARNING "DCCP: P.Data Offset(%u) "
1052                                             "too small 2\n",
1053                                dh->dccph_doff);
1054                 return 1;
1055         }
1056
1057         dh = dccp_hdr(skb);
1058
1059         /*
1060          * If P.type is not Data, Ack, or DataAck and P.X == 0 (the packet
1061          * has short sequence numbers), drop packet and return
1062          */
1063         if (dh->dccph_x == 0 &&
1064             dh->dccph_type != DCCP_PKT_DATA &&
1065             dh->dccph_type != DCCP_PKT_ACK &&
1066             dh->dccph_type != DCCP_PKT_DATAACK) {
1067                 LIMIT_NETDEBUG(KERN_WARNING "DCCP: P.type (%s) not Data, Ack "
1068                                             "nor DataAck and P.X == 0\n",
1069                                dccp_packet_name(dh->dccph_type));
1070                 return 1;
1071         }
1072
1073         /* If the header checksum is incorrect, drop packet and return */
1074         if (dccp_v4_verify_checksum(skb, skb->nh.iph->saddr,
1075                                     skb->nh.iph->daddr) < 0) {
1076                 LIMIT_NETDEBUG(KERN_WARNING "DCCP: header checksum is "
1077                                             "incorrect\n");
1078                 return 1;
1079         }
1080
1081         return 0;
1082 }
1083
1084 /* this is called when real data arrives */
1085 int dccp_v4_rcv(struct sk_buff *skb)
1086 {
1087         const struct dccp_hdr *dh;
1088         struct sock *sk;
1089         int rc;
1090
1091         /* Step 1: Check header basics: */
1092
1093         if (dccp_invalid_packet(skb))
1094                 goto discard_it;
1095
1096         dh = dccp_hdr(skb);
1097 #if 0
1098         /*
1099          * Use something like this to simulate some DATA/DATAACK loss to test
1100          * dccp_ackpkts_add, you'll get something like this on a session that
1101          * sends 10 DATA/DATAACK packets:
1102          *
1103          * ackpkts_print: 281473596467422 |0,0|3,0|0,0|3,0|0,0|3,0|0,0|3,0|0,1|
1104          *
1105          * 0, 0 means: DCCP_ACKPKTS_STATE_RECEIVED, RLE == just this packet
1106          * 0, 1 means: DCCP_ACKPKTS_STATE_RECEIVED, RLE == two adjacent packets
1107          *                                                 with the same state
1108          * 3, 0 means: DCCP_ACKPKTS_STATE_NOT_RECEIVED, RLE == just this packet
1109          *
1110          * So...
1111          *
1112          * 281473596467422 was received
1113          * 281473596467421 was not received
1114          * 281473596467420 was received
1115          * 281473596467419 was not received
1116          * 281473596467418 was received
1117          * 281473596467417 was not received
1118          * 281473596467416 was received
1119          * 281473596467415 was not received
1120          * 281473596467414 was received
1121          * 281473596467413 was received (this one was the 3way handshake
1122          *                               RESPONSE)
1123          *
1124          */
1125         if (dh->dccph_type == DCCP_PKT_DATA ||
1126             dh->dccph_type == DCCP_PKT_DATAACK) {
1127                 static int discard = 0;
1128
1129                 if (discard) {
1130                         discard = 0;
1131                         goto discard_it;
1132                 }
1133                 discard = 1;
1134         }
1135 #endif
1136         DCCP_SKB_CB(skb)->dccpd_seq  = dccp_hdr_seq(skb);
1137         DCCP_SKB_CB(skb)->dccpd_type = dh->dccph_type;
1138
1139         dccp_pr_debug("%8.8s "
1140                       "src=%u.%u.%u.%u@%-5d "
1141                       "dst=%u.%u.%u.%u@%-5d seq=%llu",
1142                       dccp_packet_name(dh->dccph_type),
1143                       NIPQUAD(skb->nh.iph->saddr), ntohs(dh->dccph_sport),
1144                       NIPQUAD(skb->nh.iph->daddr), ntohs(dh->dccph_dport),
1145                       (unsigned long long) DCCP_SKB_CB(skb)->dccpd_seq);
1146
1147         if (dccp_packet_without_ack(skb)) {
1148                 DCCP_SKB_CB(skb)->dccpd_ack_seq = DCCP_PKT_WITHOUT_ACK_SEQ;
1149                 dccp_pr_debug_cat("\n");
1150         } else {
1151                 DCCP_SKB_CB(skb)->dccpd_ack_seq = dccp_hdr_ack_seq(skb);
1152                 dccp_pr_debug_cat(", ack=%llu\n",
1153                                   (unsigned long long)
1154                                   DCCP_SKB_CB(skb)->dccpd_ack_seq);
1155         }
1156
1157         /* Step 2:
1158          *      Look up flow ID in table and get corresponding socket */
1159         sk = __inet_lookup(&dccp_hashinfo,
1160                            skb->nh.iph->saddr, dh->dccph_sport,
1161                            skb->nh.iph->daddr, ntohs(dh->dccph_dport),
1162                            inet_iif(skb));
1163
1164         /*
1165          * Step 2:
1166          *      If no socket ...
1167          *              Generate Reset(No Connection) unless P.type == Reset
1168          *              Drop packet and return
1169          */
1170         if (sk == NULL) {
1171                 dccp_pr_debug("failed to look up flow ID in table and "
1172                               "get corresponding socket\n");
1173                 goto no_dccp_socket;
1174         }
1175
1176         /*
1177          * Step 2:
1178          *      ... or S.state == TIMEWAIT,
1179          *              Generate Reset(No Connection) unless P.type == Reset
1180          *              Drop packet and return
1181          */
1182
1183         if (sk->sk_state == DCCP_TIME_WAIT) {
1184                 dccp_pr_debug("sk->sk_state == DCCP_TIME_WAIT: "
1185                               "do_time_wait\n");
1186                 goto do_time_wait;
1187         }
1188
1189         if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb)) {
1190                 dccp_pr_debug("xfrm4_policy_check failed\n");
1191                 goto discard_and_relse;
1192         }
1193
1194         if (sk_filter(sk, skb, 0)) {
1195                 dccp_pr_debug("sk_filter failed\n");
1196                 goto discard_and_relse;
1197         }
1198
1199         skb->dev = NULL;
1200
1201         bh_lock_sock(sk);
1202         rc = 0;
1203         if (!sock_owned_by_user(sk))
1204                 rc = dccp_v4_do_rcv(sk, skb);
1205         else
1206                 sk_add_backlog(sk, skb);
1207         bh_unlock_sock(sk);
1208
1209         sock_put(sk);
1210         return rc;
1211
1212 no_dccp_socket:
1213         if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
1214                 goto discard_it;
1215         /*
1216          * Step 2:
1217          *              Generate Reset(No Connection) unless P.type == Reset
1218          *              Drop packet and return
1219          */
1220         if (dh->dccph_type != DCCP_PKT_RESET) {
1221                 DCCP_SKB_CB(skb)->dccpd_reset_code =
1222                                         DCCP_RESET_CODE_NO_CONNECTION;
1223                 dccp_v4_ctl_send_reset(skb);
1224         }
1225
1226 discard_it:
1227         /* Discard frame. */
1228         kfree_skb(skb);
1229         return 0;
1230
1231 discard_and_relse:
1232         sock_put(sk);
1233         goto discard_it;
1234
1235 do_time_wait:
1236         inet_twsk_put((struct inet_timewait_sock *)sk);
1237         goto no_dccp_socket;
1238 }
1239
1240 static int dccp_v4_init_sock(struct sock *sk)
1241 {
1242         struct dccp_sock *dp = dccp_sk(sk);
1243         static int dccp_ctl_socket_init = 1;
1244
1245         dccp_options_init(&dp->dccps_options);
1246         do_gettimeofday(&dp->dccps_epoch);
1247
1248         if (dp->dccps_options.dccpo_send_ack_vector) {
1249                 dp->dccps_hc_rx_ackpkts =
1250                         dccp_ackpkts_alloc(DCCP_MAX_ACK_VECTOR_LEN,
1251                                            GFP_KERNEL);
1252
1253                 if (dp->dccps_hc_rx_ackpkts == NULL)
1254                         return -ENOMEM;
1255         }
1256
1257         /*
1258          * FIXME: We're hardcoding the CCID, and doing this at this point makes
1259          * the listening (master) sock get CCID control blocks, which is not
1260          * necessary, but for now, to not mess with the test userspace apps,
1261          * lets leave it here, later the real solution is to do this in a
1262          * setsockopt(CCIDs-I-want/accept). -acme
1263          */
1264         if (likely(!dccp_ctl_socket_init)) {
1265                 dp->dccps_hc_rx_ccid = ccid_init(dp->dccps_options.dccpo_ccid,
1266                                                  sk);
1267                 dp->dccps_hc_tx_ccid = ccid_init(dp->dccps_options.dccpo_ccid,
1268                                                  sk);
1269                 if (dp->dccps_hc_rx_ccid == NULL ||
1270                     dp->dccps_hc_tx_ccid == NULL) {
1271                         ccid_exit(dp->dccps_hc_rx_ccid, sk);
1272                         ccid_exit(dp->dccps_hc_tx_ccid, sk);
1273                         dccp_ackpkts_free(dp->dccps_hc_rx_ackpkts);
1274                         dp->dccps_hc_rx_ackpkts = NULL;
1275                         dp->dccps_hc_rx_ccid = dp->dccps_hc_tx_ccid = NULL;
1276                         return -ENOMEM;
1277                 }
1278         } else
1279                 dccp_ctl_socket_init = 0;
1280
1281         dccp_init_xmit_timers(sk);
1282         inet_csk(sk)->icsk_rto = DCCP_TIMEOUT_INIT;
1283         sk->sk_state = DCCP_CLOSED;
1284         sk->sk_write_space = dccp_write_space;
1285         dp->dccps_mss_cache = 536;
1286         dp->dccps_role = DCCP_ROLE_UNDEFINED;
1287
1288         return 0;
1289 }
1290
1291 static int dccp_v4_destroy_sock(struct sock *sk)
1292 {
1293         struct dccp_sock *dp = dccp_sk(sk);
1294
1295         /*
1296          * DCCP doesn't use sk_qrite_queue, just sk_send_head
1297          * for retransmissions
1298          */
1299         if (sk->sk_send_head != NULL) {
1300                 kfree_skb(sk->sk_send_head);
1301                 sk->sk_send_head = NULL;
1302         }
1303
1304         /* Clean up a referenced DCCP bind bucket. */
1305         if (inet_csk(sk)->icsk_bind_hash != NULL)
1306                 inet_put_port(&dccp_hashinfo, sk);
1307
1308         ccid_hc_rx_exit(dp->dccps_hc_rx_ccid, sk);
1309         ccid_hc_tx_exit(dp->dccps_hc_tx_ccid, sk);
1310         dccp_ackpkts_free(dp->dccps_hc_rx_ackpkts);
1311         dp->dccps_hc_rx_ackpkts = NULL;
1312         ccid_exit(dp->dccps_hc_rx_ccid, sk);
1313         ccid_exit(dp->dccps_hc_tx_ccid, sk);
1314         dp->dccps_hc_rx_ccid = dp->dccps_hc_tx_ccid = NULL;
1315
1316         return 0;
1317 }
1318
1319 static void dccp_v4_reqsk_destructor(struct request_sock *req)
1320 {
1321         kfree(inet_rsk(req)->opt);
1322 }
1323
1324 static struct request_sock_ops dccp_request_sock_ops = {
1325         .family         = PF_INET,
1326         .obj_size       = sizeof(struct dccp_request_sock),
1327         .rtx_syn_ack    = dccp_v4_send_response,
1328         .send_ack       = dccp_v4_reqsk_send_ack,
1329         .destructor     = dccp_v4_reqsk_destructor,
1330         .send_reset     = dccp_v4_ctl_send_reset,
1331 };
1332
1333 struct proto dccp_v4_prot = {
1334         .name                   = "DCCP",
1335         .owner                  = THIS_MODULE,
1336         .close                  = dccp_close,
1337         .connect                = dccp_v4_connect,
1338         .disconnect             = dccp_disconnect,
1339         .ioctl                  = dccp_ioctl,
1340         .init                   = dccp_v4_init_sock,
1341         .setsockopt             = dccp_setsockopt,
1342         .getsockopt             = dccp_getsockopt,
1343         .sendmsg                = dccp_sendmsg,
1344         .recvmsg                = dccp_recvmsg,
1345         .backlog_rcv            = dccp_v4_do_rcv,
1346         .hash                   = dccp_v4_hash,
1347         .unhash                 = dccp_v4_unhash,
1348         .accept                 = inet_csk_accept,
1349         .get_port               = dccp_v4_get_port,
1350         .shutdown               = dccp_shutdown,
1351         .destroy                = dccp_v4_destroy_sock,
1352         .orphan_count           = &dccp_orphan_count,
1353         .max_header             = MAX_DCCP_HEADER,
1354         .obj_size               = sizeof(struct dccp_sock),
1355         .rsk_prot               = &dccp_request_sock_ops,
1356         .twsk_obj_size          = sizeof(struct inet_timewait_sock),
1357 };