net/dccp/output.c

   1 /*
   2  *  net/dccp/output.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/dccp.h>
  14 #include <linux/kernel.h>
  15 #include <linux/skbuff.h>
  16
  17 #include <net/inet_sock.h>
  18 #include <net/sock.h>
  19
  20 #include "ackvec.h"
  21 #include "ccid.h"
  22 #include "dccp.h"
  23
  24 static inline void dccp_event_ack_sent(struct sock *sk)
  25 {
  26         inet_csk_clear_xmit_timer(sk, ICSK_TIME_DACK);
  27 }
  28
  29 static void dccp_skb_entail(struct sock *sk, struct sk_buff *skb)
  30 {
  31         skb_set_owner_w(skb, sk);
  32         WARN_ON(sk->sk_send_head);
  33         sk->sk_send_head = skb;
  34 }
  35
  36 /*
  37  * All SKB's seen here are completely headerless. It is our
  38  * job to build the DCCP header, and pass the packet down to
  39  * IP so it can do the same plus pass the packet off to the
  40  * device.
  41  */
  42 static int dccp_transmit_skb(struct sock *sk, struct sk_buff *skb)
  43 {
  44         if (likely(skb != NULL)) {
  45                 const struct inet_sock *inet = inet_sk(sk);
  46                 const struct inet_connection_sock *icsk = inet_csk(sk);
  47                 struct dccp_sock *dp = dccp_sk(sk);
  48                 struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb);
  49                 struct dccp_hdr *dh;
  50                 /* XXX For now we're using only 48 bits sequence numbers */
  51                 const u32 dccp_header_size = sizeof(*dh) +
  52                                              sizeof(struct dccp_hdr_ext) +
  53                                           dccp_packet_hdr_len(dcb->dccpd_type);
  54                 int err, set_ack = 1;
  55                 u64 ackno = dp->dccps_gsr;
  56
  57                 dccp_inc_seqno(&dp->dccps_gss);
  58
  59                 switch (dcb->dccpd_type) {
  60                 case DCCP_PKT_DATA:
  61                         set_ack = 0;
  62                         /* fall through */
  63                 case DCCP_PKT_DATAACK:
  64                         break;
  65
  66                 case DCCP_PKT_REQUEST:
  67                         set_ack = 0;
  68                         /* fall through */
  69
  70                 case DCCP_PKT_SYNC:
  71                 case DCCP_PKT_SYNCACK:
  72                         ackno = dcb->dccpd_seq;
  73                         /* fall through */
  74                 default:
  75                         /*
  76                          * Only data packets should come through with skb->sk
  77                          * set.
  78                          */
  79                         WARN_ON(skb->sk);
  80                         skb_set_owner_w(skb, sk);
  81                         break;
  82                 }
  83
  84                 dcb->dccpd_seq = dp->dccps_gss;
  85
  86                 if (dccp_insert_options(sk, skb)) {
  87                         kfree_skb(skb);
  88                         return -EPROTO;
  89                 }
  90
  91
  92                 /* Build DCCP header and checksum it. */
  93                 dh = dccp_zeroed_hdr(skb, dccp_header_size);
  94                 dh->dccph_type  = dcb->dccpd_type;
  95                 dh->dccph_sport = inet->sport;
  96                 dh->dccph_dport = inet->dport;
  97                 dh->dccph_doff  = (dccp_header_size + dcb->dccpd_opt_len) / 4;
  98                 dh->dccph_ccval = dcb->dccpd_ccval;
  99                 /* XXX For now we're using only 48 bits sequence numbers */
 100                 dh->dccph_x     = 1;
 101
 102                 dp->dccps_awh = dp->dccps_gss;
 103                 dccp_hdr_set_seq(dh, dp->dccps_gss);
 104                 if (set_ack)
 105                         dccp_hdr_set_ack(dccp_hdr_ack_bits(skb), ackno);
 106
 107                 switch (dcb->dccpd_type) {
 108                 case DCCP_PKT_REQUEST:
 109                         dccp_hdr_request(skb)->dccph_req_service =
 110                                                         dp->dccps_service;
 111                         break;
 112                 case DCCP_PKT_RESET:
 113                         dccp_hdr_reset(skb)->dccph_reset_code =
 114                                                         dcb->dccpd_reset_code;
 115                         break;
 116                 }
 117
 118                 icsk->icsk_af_ops->send_check(sk, skb->len, skb);
 119
 120                 if (set_ack)
 121                         dccp_event_ack_sent(sk);
 122
 123                 DCCP_INC_STATS(DCCP_MIB_OUTSEGS);
 124
 125                 memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
 126                 err = icsk->icsk_af_ops->queue_xmit(skb, sk, 0);
 127                 if (err <= 0)
 128                         return err;
 129
 130                 /* NET_XMIT_CN is special. It does not guarantee,
 131                  * that this packet is lost. It tells that device
 132                  * is about to start to drop packets or already
 133                  * drops some packets of the same priority and
 134                  * invokes us to send less aggressively.
 135                  */
 136                 return err == NET_XMIT_CN ? 0 : err;
 137         }
 138         return -ENOBUFS;
 139 }
 140
 141 unsigned int dccp_sync_mss(struct sock *sk, u32 pmtu)
 142 {
 143         struct inet_connection_sock *icsk = inet_csk(sk);
 144         struct dccp_sock *dp = dccp_sk(sk);
 145         int mss_now = (pmtu - icsk->icsk_af_ops->net_header_len -
 146                        sizeof(struct dccp_hdr) - sizeof(struct dccp_hdr_ext));
 147
 148         /* Now subtract optional transport overhead */
 149         mss_now -= icsk->icsk_ext_hdr_len;
 150
 151         /*
 152          * FIXME: this should come from the CCID infrastructure, where, say,
 153          * TFRC will say it wants TIMESTAMPS, ELAPSED time, etc, for now lets
 154          * put a rough estimate for NDP + TIMESTAMP + TIMESTAMP_ECHO + ELAPSED
 155          * TIME + TFRC_OPT_LOSS_EVENT_RATE + TFRC_OPT_RECEIVE_RATE + padding to
 156          * make it a multiple of 4
 157          */
 158
 159         mss_now -= ((5 + 6 + 10 + 6 + 6 + 6 + 3) / 4) * 4;
 160
 161         /* And store cached results */
 162         icsk->icsk_pmtu_cookie = pmtu;
 163         dp->dccps_mss_cache = mss_now;
 164
 165         return mss_now;
 166 }
 167
 168 EXPORT_SYMBOL_GPL(dccp_sync_mss);
 169
 170 void dccp_write_space(struct sock *sk)
 171 {
 172         read_lock(&sk->sk_callback_lock);
 173
 174         if (sk->sk_sleep && waitqueue_active(sk->sk_sleep))
 175                 wake_up_interruptible(sk->sk_sleep);
 176         /* Should agree with poll, otherwise some programs break */
 177         if (sock_writeable(sk))
 178                 sk_wake_async(sk, 2, POLL_OUT);
 179
 180         read_unlock(&sk->sk_callback_lock);
 181 }
 182
 183 /**
 184  * dccp_wait_for_ccid - Wait for ccid to tell us we can send a packet
 185  * @sk: socket to wait for
 186  * @timeo: for how long
 187  */
 188 static int dccp_wait_for_ccid(struct sock *sk, struct sk_buff *skb,
 189                               long *timeo)
 190 {
 191         struct dccp_sock *dp = dccp_sk(sk);
 192         DEFINE_WAIT(wait);
 193         long delay;
 194         int rc;
 195
 196         while (1) {
 197                 prepare_to_wait(sk->sk_sleep, &wait, TASK_INTERRUPTIBLE);
 198
 199                 if (sk->sk_err)
 200                         goto do_error;
 201                 if (!*timeo)
 202                         goto do_nonblock;
 203                 if (signal_pending(current))
 204                         goto do_interrupted;
 205
 206                 rc = ccid_hc_tx_send_packet(dp->dccps_hc_tx_ccid, sk, skb,
 207                                             skb->len);
 208                 if (rc <= 0)
 209                         break;
 210                 delay = msecs_to_jiffies(rc);
 211                 if (delay > *timeo || delay < 0)
 212                         goto do_nonblock;
 213
 214                 sk->sk_write_pending++;
 215                 release_sock(sk);
 216                 *timeo -= schedule_timeout(delay);
 217                 lock_sock(sk);
 218                 sk->sk_write_pending--;
 219         }
 220 out:
 221         finish_wait(sk->sk_sleep, &wait);
 222         return rc;
 223
 224 do_error:
 225         rc = -EPIPE;
 226         goto out;
 227 do_nonblock:
 228         rc = -EAGAIN;
 229         goto out;
 230 do_interrupted:
 231         rc = sock_intr_errno(*timeo);
 232         goto out;
 233 }
 234
 235 static void dccp_write_xmit_timer(unsigned long data) {
 236         struct sock *sk = (struct sock *)data;
 237         struct dccp_sock *dp = dccp_sk(sk);
 238
 239         bh_lock_sock(sk);
 240         if (sock_owned_by_user(sk))
 241                 sk_reset_timer(sk, &dp->dccps_xmit_timer, jiffies+1);
 242         else
 243                 dccp_write_xmit(sk, 0);
 244         bh_unlock_sock(sk);
 245         sock_put(sk);
 246 }
 247
 248 void dccp_write_xmit(struct sock *sk, int block)
 249 {
 250         struct dccp_sock *dp = dccp_sk(sk);
 251         struct sk_buff *skb;
 252         long timeo = DCCP_XMIT_TIMEO;   /* If a packet is taking longer than
 253                                            this we have other issues */
 254
 255         while ((skb = skb_peek(&sk->sk_write_queue))) {
 256                 int err = ccid_hc_tx_send_packet(dp->dccps_hc_tx_ccid, sk, skb,
 257                                          skb->len);
 258
 259                 if (err > 0) {
 260                         if (!block) {
 261                                 sk_reset_timer(sk, &dp->dccps_xmit_timer,
 262                                                 msecs_to_jiffies(err)+jiffies);
 263                                 break;
 264                         } else {
 265                                 err = dccp_wait_for_ccid(sk, skb, &timeo);
 266                                 timeo = DCCP_XMIT_TIMEO;
 267                         }
 268                         if (err) {
 269                                 printk(KERN_CRIT "%s:err at dccp_wait_for_ccid"
 270                                                  " %d\n", __FUNCTION__, err);
 271                                 dump_stack();
 272                         }
 273                 }
 274
 275                 skb_dequeue(&sk->sk_write_queue);
 276                 if (err == 0) {
 277                         struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb);
 278                         const int len = skb->len;
 279
 280                         if (sk->sk_state == DCCP_PARTOPEN) {
 281                                 /* See 8.1.5.  Handshake Completion */
 282                                 inet_csk_schedule_ack(sk);
 283                                 inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK,
 284                                                   inet_csk(sk)->icsk_rto,
 285                                                   DCCP_RTO_MAX);
 286                                 dcb->dccpd_type = DCCP_PKT_DATAACK;
 287                         } else if (dccp_ack_pending(sk))
 288                                 dcb->dccpd_type = DCCP_PKT_DATAACK;
 289                         else
 290                                 dcb->dccpd_type = DCCP_PKT_DATA;
 291
 292                         err = dccp_transmit_skb(sk, skb);
 293                         ccid_hc_tx_packet_sent(dp->dccps_hc_tx_ccid, sk, 0, len);
 294                         if (err) {
 295                                 printk(KERN_CRIT "%s:err from "
 296                                                  "ccid_hc_tx_packet_sent %d\n",
 297                                                  __FUNCTION__, err);
 298                                 dump_stack();
 299                         }
 300                 } else
 301                         kfree(skb);
 302         }
 303 }
 304
 305 int dccp_retransmit_skb(struct sock *sk, struct sk_buff *skb)
 306 {
 307         if (inet_csk(sk)->icsk_af_ops->rebuild_header(sk) != 0)
 308                 return -EHOSTUNREACH; /* Routing failure or similar. */
 309
 310         return dccp_transmit_skb(sk, (skb_cloned(skb) ?
 311                                       pskb_copy(skb, GFP_ATOMIC):
 312                                       skb_clone(skb, GFP_ATOMIC)));
 313 }
 314
 315 struct sk_buff *dccp_make_response(struct sock *sk, struct dst_entry *dst,
 316                                    struct request_sock *req)
 317 {
 318         struct dccp_hdr *dh;
 319         struct dccp_request_sock *dreq;
 320         const u32 dccp_header_size = sizeof(struct dccp_hdr) +
 321                                      sizeof(struct dccp_hdr_ext) +
 322                                      sizeof(struct dccp_hdr_response);
 323         struct sk_buff *skb = sock_wmalloc(sk, sk->sk_prot->max_header, 1,
 324                                            GFP_ATOMIC);
 325         if (skb == NULL)
 326                 return NULL;
 327
 328         /* Reserve space for headers. */
 329         skb_reserve(skb, sk->sk_prot->max_header);
 330
 331         skb->dst = dst_clone(dst);
 332         skb->csum = 0;
 333
 334         dreq = dccp_rsk(req);
 335         DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_RESPONSE;
 336         DCCP_SKB_CB(skb)->dccpd_seq  = dreq->dreq_iss;
 337
 338         if (dccp_insert_options(sk, skb)) {
 339                 kfree_skb(skb);
 340                 return NULL;
 341         }
 342
 343         dh = dccp_zeroed_hdr(skb, dccp_header_size);
 344
 345         dh->dccph_sport = inet_sk(sk)->sport;
 346         dh->dccph_dport = inet_rsk(req)->rmt_port;
 347         dh->dccph_doff  = (dccp_header_size +
 348                            DCCP_SKB_CB(skb)->dccpd_opt_len) / 4;
 349         dh->dccph_type  = DCCP_PKT_RESPONSE;
 350         dh->dccph_x     = 1;
 351         dccp_hdr_set_seq(dh, dreq->dreq_iss);
 352         dccp_hdr_set_ack(dccp_hdr_ack_bits(skb), dreq->dreq_isr);
 353         dccp_hdr_response(skb)->dccph_resp_service = dreq->dreq_service;
 354
 355         DCCP_INC_STATS(DCCP_MIB_OUTSEGS);
 356         return skb;
 357 }
 358
 359 EXPORT_SYMBOL_GPL(dccp_make_response);
 360
 361 static struct sk_buff *dccp_make_reset(struct sock *sk, struct dst_entry *dst,
 362                                        const enum dccp_reset_codes code)
 363
 364 {
 365         struct dccp_hdr *dh;
 366         struct dccp_sock *dp = dccp_sk(sk);
 367         const u32 dccp_header_size = sizeof(struct dccp_hdr) +
 368                                      sizeof(struct dccp_hdr_ext) +
 369                                      sizeof(struct dccp_hdr_reset);
 370         struct sk_buff *skb = sock_wmalloc(sk, sk->sk_prot->max_header, 1,
 371                                            GFP_ATOMIC);
 372         if (skb == NULL)
 373                 return NULL;
 374
 375         /* Reserve space for headers. */
 376         skb_reserve(skb, sk->sk_prot->max_header);
 377
 378         skb->dst = dst_clone(dst);
 379         skb->csum = 0;
 380
 381         dccp_inc_seqno(&dp->dccps_gss);
 382
 383         DCCP_SKB_CB(skb)->dccpd_reset_code = code;
 384         DCCP_SKB_CB(skb)->dccpd_type       = DCCP_PKT_RESET;
 385         DCCP_SKB_CB(skb)->dccpd_seq        = dp->dccps_gss;
 386
 387         if (dccp_insert_options(sk, skb)) {
 388                 kfree_skb(skb);
 389                 return NULL;
 390         }
 391
 392         dh = dccp_zeroed_hdr(skb, dccp_header_size);
 393
 394         dh->dccph_sport = inet_sk(sk)->sport;
 395         dh->dccph_dport = inet_sk(sk)->dport;
 396         dh->dccph_doff  = (dccp_header_size +
 397                            DCCP_SKB_CB(skb)->dccpd_opt_len) / 4;
 398         dh->dccph_type  = DCCP_PKT_RESET;
 399         dh->dccph_x     = 1;
 400         dccp_hdr_set_seq(dh, dp->dccps_gss);
 401         dccp_hdr_set_ack(dccp_hdr_ack_bits(skb), dp->dccps_gsr);
 402
 403         dccp_hdr_reset(skb)->dccph_reset_code = code;
 404         inet_csk(sk)->icsk_af_ops->send_check(sk, skb->len, skb);
 405
 406         DCCP_INC_STATS(DCCP_MIB_OUTSEGS);
 407         return skb;
 408 }
 409
 410 int dccp_send_reset(struct sock *sk, enum dccp_reset_codes code)
 411 {
 412         /*
 413          * FIXME: what if rebuild_header fails?
 414          * Should we be doing a rebuild_header here?
 415          */
 416         int err = inet_sk_rebuild_header(sk);
 417
 418         if (err == 0) {
 419                 struct sk_buff *skb = dccp_make_reset(sk, sk->sk_dst_cache,
 420                                                       code);
 421                 if (skb != NULL) {
 422                         memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
 423                         err = inet_csk(sk)->icsk_af_ops->queue_xmit(skb, sk, 0);
 424                         if (err == NET_XMIT_CN)
 425                                 err = 0;
 426                 }
 427         }
 428
 429         return err;
 430 }
 431
 432 /*
 433  * Do all connect socket setups that can be done AF independent.
 434  */
 435 static inline void dccp_connect_init(struct sock *sk)
 436 {
 437         struct dccp_sock *dp = dccp_sk(sk);
 438         struct dst_entry *dst = __sk_dst_get(sk);
 439         struct inet_connection_sock *icsk = inet_csk(sk);
 440
 441         sk->sk_err = 0;
 442         sock_reset_flag(sk, SOCK_DONE);
 443
 444         dccp_sync_mss(sk, dst_mtu(dst));
 445
 446         dccp_update_gss(sk, dp->dccps_iss);
 447         /*
 448          * SWL and AWL are initially adjusted so that they are not less than
 449          * the initial Sequence Numbers received and sent, respectively:
 450          *      SWL := max(GSR + 1 - floor(W/4), ISR),
 451          *      AWL := max(GSS - W' + 1, ISS).
 452          * These adjustments MUST be applied only at the beginning of the
 453          * connection.
 454          */
 455         dccp_set_seqno(&dp->dccps_awl, max48(dp->dccps_awl, dp->dccps_iss));
 456
 457         icsk->icsk_retransmits = 0;
 458         init_timer(&dp->dccps_xmit_timer);
 459         dp->dccps_xmit_timer.data = (unsigned long)sk;
 460         dp->dccps_xmit_timer.function = dccp_write_xmit_timer;
 461 }
 462
 463 int dccp_connect(struct sock *sk)
 464 {
 465         struct sk_buff *skb;
 466         struct inet_connection_sock *icsk = inet_csk(sk);
 467
 468         dccp_connect_init(sk);
 469
 470         skb = alloc_skb(sk->sk_prot->max_header, sk->sk_allocation);
 471         if (unlikely(skb == NULL))
 472                 return -ENOBUFS;
 473
 474         /* Reserve space for headers. */
 475         skb_reserve(skb, sk->sk_prot->max_header);
 476
 477         DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_REQUEST;
 478         skb->csum = 0;
 479
 480         dccp_skb_entail(sk, skb);
 481         dccp_transmit_skb(sk, skb_clone(skb, GFP_KERNEL));
 482         DCCP_INC_STATS(DCCP_MIB_ACTIVEOPENS);
 483
 484         /* Timer for repeating the REQUEST until an answer. */
 485         inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
 486                                   icsk->icsk_rto, DCCP_RTO_MAX);
 487         return 0;
 488 }
 489
 490 EXPORT_SYMBOL_GPL(dccp_connect);
 491
 492 void dccp_send_ack(struct sock *sk)
 493 {
 494         /* If we have been reset, we may not send again. */
 495         if (sk->sk_state != DCCP_CLOSED) {
 496                 struct sk_buff *skb = alloc_skb(sk->sk_prot->max_header,
 497                                                 GFP_ATOMIC);
 498
 499                 if (skb == NULL) {
 500                         inet_csk_schedule_ack(sk);
 501                         inet_csk(sk)->icsk_ack.ato = TCP_ATO_MIN;
 502                         inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK,
 503                                                   TCP_DELACK_MAX,
 504                                                   DCCP_RTO_MAX);
 505                         return;
 506                 }
 507
 508                 /* Reserve space for headers */
 509                 skb_reserve(skb, sk->sk_prot->max_header);
 510                 skb->csum = 0;
 511                 DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_ACK;
 512                 dccp_transmit_skb(sk, skb);
 513         }
 514 }
 515
 516 EXPORT_SYMBOL_GPL(dccp_send_ack);
 517
 518 void dccp_send_delayed_ack(struct sock *sk)
 519 {
 520         struct inet_connection_sock *icsk = inet_csk(sk);
 521         /*
 522          * FIXME: tune this timer. elapsed time fixes the skew, so no problem
 523          * with using 2s, and active senders also piggyback the ACK into a
 524          * DATAACK packet, so this is really for quiescent senders.
 525          */
 526         unsigned long timeout = jiffies + 2 * HZ;
 527
 528         /* Use new timeout only if there wasn't a older one earlier. */
 529         if (icsk->icsk_ack.pending & ICSK_ACK_TIMER) {
 530                 /* If delack timer was blocked or is about to expire,
 531                  * send ACK now.
 532                  *
 533                  * FIXME: check the "about to expire" part
 534                  */
 535                 if (icsk->icsk_ack.blocked) {
 536                         dccp_send_ack(sk);
 537                         return;
 538                 }
 539
 540                 if (!time_before(timeout, icsk->icsk_ack.timeout))
 541                         timeout = icsk->icsk_ack.timeout;
 542         }
 543         icsk->icsk_ack.pending |= ICSK_ACK_SCHED | ICSK_ACK_TIMER;
 544         icsk->icsk_ack.timeout = timeout;
 545         sk_reset_timer(sk, &icsk->icsk_delack_timer, timeout);
 546 }
 547
 548 void dccp_send_sync(struct sock *sk, const u64 seq,
 549                     const enum dccp_pkt_type pkt_type)
 550 {
 551         /*
 552          * We are not putting this on the write queue, so
 553          * dccp_transmit_skb() will set the ownership to this
 554          * sock.
 555          */
 556         struct sk_buff *skb = alloc_skb(sk->sk_prot->max_header, GFP_ATOMIC);
 557
 558         if (skb == NULL)
 559                 /* FIXME: how to make sure the sync is sent? */
 560                 return;
 561
 562         /* Reserve space for headers and prepare control bits. */
 563         skb_reserve(skb, sk->sk_prot->max_header);
 564         skb->csum = 0;
 565         DCCP_SKB_CB(skb)->dccpd_type = pkt_type;
 566         DCCP_SKB_CB(skb)->dccpd_seq = seq;
 567
 568         dccp_transmit_skb(sk, skb);
 569 }
 570
 571 EXPORT_SYMBOL_GPL(dccp_send_sync);
 572
 573 /*
 574  * Send a DCCP_PKT_CLOSE/CLOSEREQ. The caller locks the socket for us. This
 575  * cannot be allowed to fail queueing a DCCP_PKT_CLOSE/CLOSEREQ frame under
 576  * any circumstances.
 577  */
 578 void dccp_send_close(struct sock *sk, const int active)
 579 {
 580         struct dccp_sock *dp = dccp_sk(sk);
 581         struct sk_buff *skb;
 582         const gfp_t prio = active ? GFP_KERNEL : GFP_ATOMIC;
 583
 584         skb = alloc_skb(sk->sk_prot->max_header, prio);
 585         if (skb == NULL)
 586                 return;
 587
 588         /* Reserve space for headers and prepare control bits. */
 589         skb_reserve(skb, sk->sk_prot->max_header);
 590         skb->csum = 0;
 591         DCCP_SKB_CB(skb)->dccpd_type = dp->dccps_role == DCCP_ROLE_CLIENT ?
 592                                         DCCP_PKT_CLOSE : DCCP_PKT_CLOSEREQ;
 593
 594         if (active) {
 595                 dccp_write_xmit(sk, 1);
 596                 dccp_skb_entail(sk, skb);
 597                 dccp_transmit_skb(sk, skb_clone(skb, prio));
 598                 /* FIXME do we need a retransmit timer here? */
 599         } else
 600                 dccp_transmit_skb(sk, skb);
 601 }