src/transport/transport_api.c

   1 /*
   2      This file is part of GNUnet.
   3      (C) 2009 Christian Grothoff (and other contributing authors)
   4
   5      GNUnet is free software; you can redistribute it and/or modify
   6      it under the terms of the GNU General Public License as published
   7      by the Free Software Foundation; either version 2, or (at your
   8      option) any later version.
   9
  10      GNUnet is distributed in the hope that it will be useful, but
  11      WITHOUT ANY WARRANTY; without even the implied warranty of
  12      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13      General Public License for more details.
  14
  15      You should have received a copy of the GNU General Public License
  16      along with GNUnet; see the file COPYING.  If not, write to the
  17      Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  18      Boston, MA 02111-1307, USA.
  19 */
  20
  21 /**
  22  * @file transport/transport_api.c
  23  * @brief library to access the low-level P2P IO service
  24  * @author Christian Grothoff
  25  *
  26  * TODO:
  27  * - set_quota with low bandwidth should cause peer
  28  *   disconnects (currently never does that) (MINOR)
  29  */
  30 #include "platform.h"
  31 #include "gnunet_client_lib.h"
  32 #include "gnunet_arm_service.h"
  33 #include "gnunet_hello_lib.h"
  34 #include "gnunet_protocols.h"
  35 #include "gnunet_server_lib.h"
  36 #include "gnunet_time_lib.h"
  37 #include "gnunet_transport_service.h"
  38 #include "transport.h"
  39
  40 /**
  41  * After how long do we give up on transmitting a HELLO
  42  * to the service?
  43  */
  44 #define OFFER_HELLO_TIMEOUT GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_SECONDS, 30)
  45
  46 /**
  47  * After how long do we automatically retry an unsuccessful
  48  * CONNECT request?
  49  */
  50 #define CONNECT_RETRY_TIMEOUT GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_MILLISECONDS, 750)
  51
  52 /**
  53  * How long should ARM wait when starting up the
  54  * transport service before reporting back?
  55  */
  56 #define START_SERVICE_TIMEOUT GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_SECONDS, 5)
  57
  58 /**
  59  * How long should ARM wait when stopping the
  60  * transport service before reporting back?
  61  */
  62 #define STOP_SERVICE_TIMEOUT GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_SECONDS, 5)
  63
  64 /**
  65  * Entry in linked list of all of our current neighbours.
  66  */
  67 struct NeighbourList
  68 {
  69
  70   /**
  71    * This is a linked list.
  72    */
  73   struct NeighbourList *next;
  74
  75   /**
  76    * Active transmit handle, can be NULL.  Used to move
  77    * from ready to wait list on disconnect and to block
  78    * two transmissions to the same peer from being scheduled
  79    * at the same time.
  80    */
  81   struct GNUNET_TRANSPORT_TransmitHandle *transmit_handle;
  82
  83   /**
  84    * Identity of this neighbour.
  85    */
  86   struct GNUNET_PeerIdentity id;
  87
  88   /**
  89    * At what time did we reset last_sent last?
  90    */
  91   struct GNUNET_TIME_Absolute last_quota_update;
  92
  93   /**
  94    * How many bytes have we sent since the "last_quota_update"
  95    * timestamp?
  96    */
  97   uint64_t last_sent;
  98
  99   /**
 100    * Quota for outbound traffic to the neighbour in bytes/ms.
 101    */
 102   uint32_t quota_out;
 103
 104   /**
 105    * Set to GNUNET_YES if we are currently allowed to
 106    * transmit a message to the transport service for this
 107    * peer, GNUNET_NO otherwise.
 108    */
 109   int transmit_ok;
 110
 111   /**
 112    * Set to GNUNET_YES if we have received an ACK for the
 113    * given peer.  Peers that receive our HELLO always respond
 114    * with an ACK to let us know that we are successfully
 115    * communicating.  Note that a PING can not be used for this
 116    * since PINGs are only send if a HELLO address requires
 117    * confirmation (and also, PINGs are not passed to the
 118    * transport API itself).
 119    */
 120   int received_ack;
 121
 122 };
 123
 124
 125 /**
 126  * Linked list of requests from clients for our HELLO
 127  * that were deferred.
 128  */
 129 struct HelloWaitList
 130 {
 131
 132   /**
 133    * This is a linked list.
 134    */
 135   struct HelloWaitList *next;
 136
 137   /**
 138    * Reference back to our transport handle.
 139    */
 140   struct GNUNET_TRANSPORT_Handle *handle;
 141
 142   /**
 143    * Callback to call once we got our HELLO.
 144    */
 145   GNUNET_TRANSPORT_ReceiveCallback rec;
 146
 147   /**
 148    * Closure for rec.
 149    */
 150   void *rec_cls;
 151
 152   /**
 153    * When to time out (call rec with NULL).
 154    */
 155   struct GNUNET_TIME_Absolute timeout;
 156
 157   /**
 158    * Timeout task (used to trigger timeout,
 159    * cancel if we get the HELLO in time).
 160    */
 161   GNUNET_SCHEDULER_TaskIdentifier task;
 162
 163
 164 };
 165
 166
 167 /**
 168  * Opaque handle for a transmission-ready request.
 169  */
 170 struct GNUNET_TRANSPORT_TransmitHandle
 171 {
 172
 173   /**
 174    * We keep the transmit handles that are waiting for
 175    * a transport-level connection in a doubly linked list.
 176    */
 177   struct GNUNET_TRANSPORT_TransmitHandle *next;
 178
 179   /**
 180    * We keep the transmit handles that are waiting for
 181    * a transport-level connection in a doubly linked list.
 182    */
 183   struct GNUNET_TRANSPORT_TransmitHandle *prev;
 184
 185   /**
 186    * Handle of the main transport data structure.
 187    */
 188   struct GNUNET_TRANSPORT_Handle *handle;
 189
 190   /**
 191    * Neighbour for this handle, can be NULL if the service
 192    * is not yet connected to the target.
 193    */
 194   struct NeighbourList *neighbour;
 195
 196   /**
 197    * Which peer is this transmission going to be for?  All
 198    * zeros if it is control-traffic to the service.
 199    */
 200   struct GNUNET_PeerIdentity target;
 201
 202   /**
 203    * Function to call when notify_size bytes are available
 204    * for transmission.
 205    */
 206   GNUNET_CONNECTION_TransmitReadyNotify notify;
 207
 208   /**
 209    * Closure for notify.
 210    */
 211   void *notify_cls;
 212
 213   /**
 214    * transmit_ready task Id.  The task is used to introduce the
 215    * artificial delay that may be required to maintain the bandwidth
 216    * limits.  Later, this will be the ID of the "transmit_timeout"
 217    * task which is used to signal a timeout if the transmission could
 218    * not be done in a timely fashion.
 219    */
 220   GNUNET_SCHEDULER_TaskIdentifier notify_delay_task;
 221
 222   /**
 223    * Timeout for this request.
 224    */
 225   struct GNUNET_TIME_Absolute timeout;
 226
 227   /**
 228    * How many bytes is our notify callback waiting for?
 229    */
 230   size_t notify_size;
 231
 232   /**
 233    * How important is this message?
 234    */
 235   unsigned int priority;
 236
 237 };
 238
 239
 240 /**
 241  * Handle for the transport service (includes all of the
 242  * state for the transport service).
 243  */
 244 struct GNUNET_TRANSPORT_Handle
 245 {
 246
 247   /**
 248    * Closure for the callbacks.
 249    */
 250   void *cls;
 251
 252   /**
 253    * Function to call for received data.
 254    */
 255   GNUNET_TRANSPORT_ReceiveCallback rec;
 256
 257   /**
 258    * function to call on connect events
 259    */
 260   GNUNET_TRANSPORT_NotifyConnect nc_cb;
 261
 262   /**
 263    * function to call on disconnect events
 264    */
 265   GNUNET_TRANSPORT_NotifyDisconnect nd_cb;
 266
 267   /**
 268    * The current HELLO message for this peer.  Updated
 269    * whenever transports change their addresses.
 270    */
 271   struct GNUNET_HELLO_Message *my_hello;
 272
 273   /**
 274    * My client connection to the transport service.
 275    */
 276   struct GNUNET_CLIENT_Connection *client;
 277
 278   /**
 279    * Handle to our registration with the client for notification.
 280    */
 281   struct GNUNET_CLIENT_TransmitHandle *network_handle;
 282
 283   /**
 284    * Linked list of transmit handles that are waiting for the
 285    * transport to connect to the respective peer.  When we
 286    * receive notification that the transport connected to a
 287    * peer, we go over this list and check if someone has already
 288    * requested a transmission to the new peer; if so, we trigger
 289    * the next step.
 290    */
 291   struct GNUNET_TRANSPORT_TransmitHandle *connect_wait_head;
 292
 293   /**
 294    * Linked list of transmit handles that are waiting for the
 295    * transport to be ready for transmission to the respective
 296    * peer.  When we
 297    * receive notification that the transport disconnected from
 298    * a peer, we go over this list and move the entry back to
 299    * the connect_wait list.
 300    */
 301   struct GNUNET_TRANSPORT_TransmitHandle *connect_ready_head;
 302
 303   /**
 304    * Linked list of pending requests for our HELLO.
 305    */
 306   struct HelloWaitList *hwl_head;
 307
 308   /**
 309    * My scheduler.
 310    */
 311   struct GNUNET_SCHEDULER_Handle *sched;
 312
 313   /**
 314    * My configuration.
 315    */
 316   const struct GNUNET_CONFIGURATION_Handle *cfg;
 317
 318   /**
 319    * Linked list of the current neighbours of this peer.
 320    */
 321   struct NeighbourList *neighbours;
 322
 323   /**
 324    * ID of the task trying to reconnect to the
 325    * service.
 326    */
 327   GNUNET_SCHEDULER_TaskIdentifier reconnect_task;
 328
 329   /**
 330    * Delay until we try to reconnect.
 331    */
 332   struct GNUNET_TIME_Relative reconnect_delay;
 333
 334   /**
 335    * Do we currently have a transmission pending?
 336    * (schedule transmission was called but has not
 337    * yet succeeded)?
 338    */
 339   int transmission_scheduled;
 340 };
 341
 342
 343 static struct NeighbourList *
 344 find_neighbour (struct GNUNET_TRANSPORT_Handle *h,
 345                 const struct GNUNET_PeerIdentity *peer)
 346 {
 347   struct NeighbourList *pos;
 348
 349   pos = h->neighbours;
 350   while ((pos != NULL) &&
 351          (0 != memcmp (peer, &pos->id, sizeof (struct GNUNET_PeerIdentity))))
 352     pos = pos->next;
 353   return pos;
 354 }
 355
 356
 357 /**
 358  * Schedule the task to send one message from the
 359  * connect_ready list to the service.
 360  */
 361 static void schedule_transmission (struct GNUNET_TRANSPORT_Handle *h);
 362
 363
 364 /**
 365  * Transmit message to client...
 366  */
 367 static size_t
 368 transport_notify_ready (void *cls, size_t size, void *buf)
 369 {
 370   struct GNUNET_TRANSPORT_Handle *h = cls;
 371   struct GNUNET_TRANSPORT_TransmitHandle *th;
 372   struct NeighbourList *n;
 373   size_t ret;
 374   char *cbuf;
 375
 376   h->network_handle = NULL;
 377   h->transmission_scheduled = GNUNET_NO;
 378   if (buf == NULL)
 379     {
 380 #if DEBUG_TRANSPORT
 381       GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 382                   "Could not transmit to transport service, cancelling pending requests\n");
 383 #endif
 384       th = h->connect_ready_head;
 385       if (th->next != NULL)
 386         th->next->prev = NULL;
 387       h->connect_ready_head = th->next;
 388       if (NULL != (n = th->neighbour))
 389         {
 390           GNUNET_assert (n->transmit_handle == th);
 391           n->transmit_handle = NULL;
 392         }
 393       if (th->notify_delay_task != GNUNET_SCHEDULER_NO_TASK)
 394         {
 395           GNUNET_SCHEDULER_cancel (h->sched, th->notify_delay_task);
 396           th->notify_delay_task = GNUNET_SCHEDULER_NO_TASK;
 397         }
 398       GNUNET_assert (0 == th->notify (th->notify_cls, 0, NULL));
 399       GNUNET_free (th);
 400       if (h->connect_ready_head != NULL)
 401         schedule_transmission (h);      /* FIXME: is this ok? */
 402       return 0;
 403     }
 404 #if DEBUG_TRANSPORT
 405   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 406               "Ready to transmit %u bytes to transport service\n", size);
 407 #endif
 408   cbuf = buf;
 409   ret = 0;
 410   h->network_handle = NULL;
 411   h->transmission_scheduled = GNUNET_NO;
 412   while ((h->connect_ready_head != NULL) &&
 413          (h->connect_ready_head->notify_size <= size))
 414     {
 415       th = h->connect_ready_head;
 416       if (th->notify_delay_task != GNUNET_SCHEDULER_NO_TASK)
 417         {
 418           GNUNET_SCHEDULER_cancel (h->sched, th->notify_delay_task);
 419           th->notify_delay_task = GNUNET_SCHEDULER_NO_TASK;
 420         }
 421       GNUNET_assert (th->notify_size <= size);
 422       if (th->next != NULL)
 423         th->next->prev = NULL;
 424       h->connect_ready_head = th->next;
 425       if (NULL != (n = th->neighbour))
 426         {
 427           GNUNET_assert (n->transmit_handle == th);
 428           n->transmit_handle = NULL;
 429         }
 430       ret += th->notify (th->notify_cls, size, &cbuf[ret]);
 431       GNUNET_free (th);
 432       if (n != NULL)
 433         n->last_sent += ret;
 434       size -= ret;
 435     }
 436   if (h->connect_ready_head != NULL)
 437     schedule_transmission (h);
 438 #if DEBUG_TRANSPORT
 439   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 440               "Transmitting %u bytes to transport service\n", ret);
 441 #endif
 442   return ret;
 443 }
 444
 445
 446 /**
 447  * Schedule the task to send one message from the
 448  * connect_ready list to the service.
 449  */
 450 static void
 451 schedule_transmission (struct GNUNET_TRANSPORT_Handle *h)
 452 {
 453   struct GNUNET_TRANSPORT_TransmitHandle *th;
 454
 455   GNUNET_assert (NULL == h->network_handle);
 456   if (h->client == NULL)
 457     {
 458       GNUNET_log (GNUNET_ERROR_TYPE_INFO,
 459                   "Could not yet schedule transmission: we are not yet connected to the transport service!\n");
 460       return;                   /* not yet connected */
 461     }
 462   th = h->connect_ready_head;
 463   if (th == NULL)
 464     return;                     /* no request pending */
 465   if (th->notify_delay_task != GNUNET_SCHEDULER_NO_TASK)
 466     {
 467       /* remove existing time out task, will be integrated
 468          with transmit_ready notification! */
 469       GNUNET_SCHEDULER_cancel (h->sched, th->notify_delay_task);
 470       th->notify_delay_task = GNUNET_SCHEDULER_NO_TASK;
 471     }
 472   h->transmission_scheduled = GNUNET_YES;
 473   h->network_handle = GNUNET_CLIENT_notify_transmit_ready (h->client,
 474                                                            th->notify_size,
 475                                                            GNUNET_TIME_absolute_get_remaining
 476                                                            (th->timeout),
 477                                                            GNUNET_NO,
 478                                                            &transport_notify_ready,
 479                                                            h);
 480   GNUNET_assert (NULL != h->network_handle);
 481 }
 482
 483
 484 /**
 485  * Insert the given transmit handle in the given sorted
 486  * doubly linked list based on timeout.
 487  *
 488  * @param head pointer to the head of the linked list
 489  * @param th element to insert into the list
 490  */
 491 static void
 492 insert_transmit_handle (struct GNUNET_TRANSPORT_TransmitHandle **head,
 493                         struct GNUNET_TRANSPORT_TransmitHandle *th)
 494 {
 495   struct GNUNET_TRANSPORT_TransmitHandle *pos;
 496   struct GNUNET_TRANSPORT_TransmitHandle *prev;
 497
 498   pos = *head;
 499   prev = NULL;
 500   while ((pos != NULL) && (pos->timeout.value < th->timeout.value))
 501     {
 502       prev = pos;
 503       pos = pos->next;
 504     }
 505   if (prev == NULL)
 506     {
 507       th->next = *head;
 508       if (th->next != NULL)
 509         th->next->prev = th;
 510       *head = th;
 511     }
 512   else
 513     {
 514       th->next = pos;
 515       th->prev = prev;
 516       prev->next = th;
 517       if (pos != NULL)
 518         pos->prev = th;
 519     }
 520 }
 521
 522
 523 /**
 524  * Cancel a pending notify delay task (if pending) and also remove the
 525  * given transmit handle from whatever list is on.
 526  *
 527  * @param th handle for the transmission request to manipulate
 528  */
 529 static void
 530 remove_from_any_list (struct GNUNET_TRANSPORT_TransmitHandle *th)
 531 {
 532   struct GNUNET_TRANSPORT_Handle *h;
 533
 534   h = th->handle;
 535   if (th->notify_delay_task != GNUNET_SCHEDULER_NO_TASK)
 536     {
 537       GNUNET_SCHEDULER_cancel (h->sched, th->notify_delay_task);
 538       th->notify_delay_task = GNUNET_SCHEDULER_NO_TASK;
 539     }
 540   if (th->prev == NULL)
 541     {
 542       if (th == h->connect_wait_head)
 543         h->connect_wait_head = th->next;
 544       else
 545         h->connect_ready_head = th->next;
 546     }
 547   else
 548     {
 549       th->prev->next = th->next;
 550     }
 551   if (th->next != NULL)
 552     th->next->prev = th->prev;
 553 }
 554
 555
 556 /**
 557  * Schedule a request to connect to the given
 558  * neighbour (and if successful, add the specified
 559  * handle to the wait list).
 560  *
 561  * @param th handle for a request to transmit once we
 562  *        have connected
 563  */
 564 static void try_connect (struct GNUNET_TRANSPORT_TransmitHandle *th);
 565
 566
 567 /**
 568  * Called when our transmit request timed out before any transport
 569  * reported success connecting to the desired peer or before the
 570  * transport was ready to receive.  Signal error and free
 571  * TransmitHandle.
 572  */
 573 static void
 574 peer_transmit_timeout (void *cls,
 575                        const struct GNUNET_SCHEDULER_TaskContext *tc)
 576 {
 577   struct GNUNET_TRANSPORT_TransmitHandle *th = cls;
 578
 579   th->notify_delay_task = GNUNET_SCHEDULER_NO_TASK;
 580   if (th->neighbour != NULL)
 581     th->neighbour->transmit_handle = NULL;
 582 #if DEBUG_TRANSPORT
 583   GNUNET_log (GNUNET_ERROR_TYPE_INFO,
 584               "Request for transmission to peer `%s' timed out.\n",
 585               GNUNET_i2s (&th->target));
 586 #endif
 587   remove_from_any_list (th);
 588   th->notify (th->notify_cls, 0, NULL);
 589   GNUNET_free (th);
 590 }
 591
 592
 593
 594
 595 /**
 596  * Queue control request for transmission to the transport
 597  * service.
 598  *
 599  * @param h handle to the transport service
 600  * @param size number of bytes to be transmitted
 601  * @param at_head request must be added to the head of the queue
 602  *        (otherwise request will be appended)
 603  * @param timeout how long this transmission can wait (at most)
 604  * @param notify function to call to get the content
 605  * @param notify_cls closure for notify
 606  */
 607 static void
 608 schedule_control_transmit (struct GNUNET_TRANSPORT_Handle *h,
 609                            size_t size,
 610                            int at_head,
 611                            struct GNUNET_TIME_Relative timeout,
 612                            GNUNET_CONNECTION_TransmitReadyNotify notify,
 613                            void *notify_cls)
 614 {
 615   struct GNUNET_TRANSPORT_TransmitHandle *th;
 616
 617 #if DEBUG_TRANSPORT
 618   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 619               "Control transmit of %u bytes within %llums requested\n",
 620               size, (unsigned long long) timeout.value);
 621 #endif
 622   th = GNUNET_malloc (sizeof (struct GNUNET_TRANSPORT_TransmitHandle));
 623   th->handle = h;
 624   th->notify = notify;
 625   th->notify_cls = notify_cls;
 626   th->timeout = GNUNET_TIME_relative_to_absolute (timeout);
 627   th->notify_size = size;
 628   th->notify_delay_task
 629     = GNUNET_SCHEDULER_add_delayed (h->sched,
 630                                     timeout, &peer_transmit_timeout, th);
 631   if (at_head)
 632     {
 633       th->next = h->connect_ready_head;
 634       h->connect_ready_head = th;
 635       if (th->next != NULL)
 636         th->next->prev = th;
 637     }
 638   else
 639     {
 640       insert_transmit_handle (&h->connect_ready_head, th);
 641     }
 642   if (GNUNET_NO == h->transmission_scheduled)
 643     schedule_transmission (h);
 644 }
 645
 646
 647 /**
 648  * Update the quota values for the given neighbour now.
 649  */
 650 static void
 651 update_quota (struct NeighbourList *n)
 652 {
 653   struct GNUNET_TIME_Relative delta;
 654   uint64_t allowed;
 655   uint64_t remaining;
 656
 657   delta = GNUNET_TIME_absolute_get_duration (n->last_quota_update);
 658   allowed = delta.value * n->quota_out;
 659   if (n->last_sent < allowed)
 660     {
 661       remaining = allowed - n->last_sent;
 662       if (n->quota_out > 0)
 663         remaining /= n->quota_out;
 664       else
 665         remaining = 0;
 666       if (remaining > MAX_BANDWIDTH_CARRY)
 667         remaining = MAX_BANDWIDTH_CARRY;
 668       n->last_sent = 0;
 669       n->last_quota_update = GNUNET_TIME_absolute_get ();
 670       n->last_quota_update.value -= remaining;
 671     }
 672   else
 673     {
 674       n->last_sent -= allowed;
 675       n->last_quota_update = GNUNET_TIME_absolute_get ();
 676     }
 677 }
 678
 679
 680 struct SetQuotaContext
 681 {
 682   struct GNUNET_TRANSPORT_Handle *handle;
 683
 684   struct GNUNET_PeerIdentity target;
 685
 686   GNUNET_SCHEDULER_Task cont;
 687
 688   void *cont_cls;
 689
 690   struct GNUNET_TIME_Absolute timeout;
 691
 692   uint32_t quota_in;
 693 };
 694
 695
 696 static size_t
 697 send_set_quota (void *cls, size_t size, void *buf)
 698 {
 699   struct SetQuotaContext *sqc = cls;
 700   struct QuotaSetMessage *msg;
 701
 702   if (buf == NULL)
 703     {
 704       GNUNET_SCHEDULER_add_continuation (sqc->handle->sched,
 705                                          sqc->cont,
 706                                          sqc->cont_cls,
 707                                          GNUNET_SCHEDULER_REASON_TIMEOUT);
 708       GNUNET_free (sqc);
 709       return 0;
 710     }
 711 #if DEBUG_TRANSPORT
 712   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 713               "Transmitting `%s' request with respect to `%4s'.\n",
 714               "SET_QUOTA", GNUNET_i2s (&sqc->target));
 715 #endif
 716   GNUNET_assert (size >= sizeof (struct QuotaSetMessage));
 717   msg = buf;
 718   msg->header.size = htons (sizeof (struct QuotaSetMessage));
 719   msg->header.type = htons (GNUNET_MESSAGE_TYPE_TRANSPORT_SET_QUOTA);
 720   msg->quota_in = htonl (sqc->quota_in);
 721   memcpy (&msg->peer, &sqc->target, sizeof (struct GNUNET_PeerIdentity));
 722   if (sqc->cont != NULL)
 723     GNUNET_SCHEDULER_add_continuation (sqc->handle->sched,
 724                                        sqc->cont,
 725                                        sqc->cont_cls,
 726                                        GNUNET_SCHEDULER_REASON_PREREQ_DONE);
 727   GNUNET_free (sqc);
 728   return sizeof (struct QuotaSetMessage);
 729 }
 730
 731
 732 /**
 733  * Set the share of incoming bandwidth for the given
 734  * peer to the specified amount.
 735  *
 736  * @param handle connection to transport service
 737  * @param target who's bandwidth quota is being changed
 738  * @param quota_in incoming bandwidth quota in bytes per ms; 0 can
 739  *        be used to force all traffic to be discarded
 740  * @param quota_out outgoing bandwidth quota in bytes per ms; 0 can
 741  *        be used to force all traffic to be discarded
 742  * @param timeout how long to wait until signaling failure if
 743  *        we can not communicate the quota change
 744  * @param cont continuation to call when done, will be called
 745  *        either with reason "TIMEOUT" or with reason "PREREQ_DONE"
 746  * @param cont_cls closure for continuation
 747  */
 748 void
 749 GNUNET_TRANSPORT_set_quota (struct GNUNET_TRANSPORT_Handle *handle,
 750                             const struct GNUNET_PeerIdentity *target,
 751                             uint32_t quota_in,
 752                             uint32_t quota_out,
 753                             struct GNUNET_TIME_Relative timeout,
 754                             GNUNET_SCHEDULER_Task cont, void *cont_cls)
 755 {
 756   struct NeighbourList *n;
 757   struct SetQuotaContext *sqc;
 758
 759   n = find_neighbour (handle, target);
 760   if (n != NULL)
 761     {
 762       update_quota (n);
 763       if (n->quota_out < quota_out)
 764         n->last_quota_update = GNUNET_TIME_absolute_get ();
 765       n->quota_out = quota_out;
 766     }
 767   sqc = GNUNET_malloc (sizeof (struct SetQuotaContext));
 768   sqc->handle = handle;
 769   sqc->target = *target;
 770   sqc->cont = cont;
 771   sqc->cont_cls = cont_cls;
 772   sqc->timeout = GNUNET_TIME_relative_to_absolute (timeout);
 773   sqc->quota_in = quota_in;
 774   schedule_control_transmit (handle,
 775                              sizeof (struct QuotaSetMessage),
 776                              GNUNET_NO, timeout, &send_set_quota, sqc);
 777 }
 778
 779
 780 /**
 781  * A "get_hello" request has timed out.  Signal the client
 782  * and clean up.
 783  */
 784 static void
 785 hello_wait_timeout (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
 786 {
 787   struct HelloWaitList *hwl = cls;
 788   struct HelloWaitList *pos;
 789   struct HelloWaitList *prev;
 790
 791   hwl->task = GNUNET_SCHEDULER_NO_TASK;
 792   if (GNUNET_TIME_absolute_get_remaining (hwl->timeout).value > 0)
 793     {
 794 #if DEBUG_TRANSPORT
 795       GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 796                   _
 797                   ("First attempt to obtain `%s' from transport service failed, will try again for %llums.\n"),
 798                   "HELLO",
 799                   GNUNET_TIME_absolute_get_remaining (hwl->timeout).value);
 800 #endif
 801       hwl->task = GNUNET_SCHEDULER_add_delayed (hwl->handle->sched,
 802                                                 GNUNET_TIME_absolute_get_remaining
 803                                                 (hwl->timeout),
 804                                                 &hello_wait_timeout, hwl);
 805       return;
 806     }
 807   /* signal timeout */
 808   GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
 809               _("Timeout trying to obtain `%s' from transport service.\n"),
 810               "HELLO");
 811   prev = NULL;
 812   pos = hwl->handle->hwl_head;
 813   while (pos != hwl)
 814     {
 815       GNUNET_assert (pos != NULL);
 816       prev = pos;
 817       pos = pos->next;
 818     }
 819   if (prev == NULL)
 820     hwl->handle->hwl_head = hwl->next;
 821   else
 822     prev->next = hwl->next;
 823   if (hwl->rec != NULL)
 824     hwl->rec (hwl->rec_cls, GNUNET_TIME_UNIT_ZERO, NULL, NULL);
 825   GNUNET_free (hwl);
 826 }
 827
 828
 829 /**
 830  * Obtain the HELLO message for this peer.
 831  *
 832  * @param handle connection to transport service
 833  * @param timeout how long to wait for the HELLO
 834  * @param rec function to call with the HELLO, sender will be our peer
 835  *            identity; message and sender will be NULL on timeout
 836  *            (handshake with transport service pending/failed).
 837  *             cost estimate will be 0.
 838  * @param rec_cls closure for rec
 839  */
 840 void
 841 GNUNET_TRANSPORT_get_hello (struct GNUNET_TRANSPORT_Handle *handle,
 842                             struct GNUNET_TIME_Relative timeout,
 843                             GNUNET_TRANSPORT_ReceiveCallback rec,
 844                             void *rec_cls)
 845 {
 846   struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded pk;
 847   struct GNUNET_PeerIdentity me;
 848   struct HelloWaitList *hwl;
 849
 850   if (handle->my_hello == NULL)
 851     {
 852       hwl = GNUNET_malloc (sizeof (struct HelloWaitList));
 853       hwl->next = handle->hwl_head;
 854       handle->hwl_head = hwl;
 855       hwl->handle = handle;
 856       hwl->rec = rec;
 857       hwl->rec_cls = rec_cls;
 858       hwl->timeout = GNUNET_TIME_relative_to_absolute (timeout);
 859       hwl->task = GNUNET_SCHEDULER_add_delayed (handle->sched,
 860                                                 timeout,
 861                                                 &hello_wait_timeout, hwl);
 862       return;
 863     }
 864   GNUNET_assert (GNUNET_OK == GNUNET_HELLO_get_key (handle->my_hello, &pk));
 865   GNUNET_CRYPTO_hash (&pk,
 866                       sizeof (struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded),
 867                       &me.hashPubKey);
 868
 869   rec (rec_cls,
 870        GNUNET_TIME_UNIT_ZERO,
 871        &me, (const struct GNUNET_MessageHeader *) handle->my_hello);
 872 }
 873
 874
 875 static size_t
 876 send_hello (void *cls, size_t size, void *buf)
 877 {
 878   struct GNUNET_MessageHeader *hello = cls;
 879   uint16_t msize;
 880
 881   if (buf == NULL)
 882     {
 883 #if DEBUG_TRANSPORT
 884       GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
 885                   "Timeout while trying to transmit `%s' request.\n",
 886                   "HELLO");
 887 #endif
 888       GNUNET_free (hello);
 889       return 0;
 890     }
 891 #if DEBUG_TRANSPORT
 892   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 893               "Transmitting `%s' request.\n", "HELLO");
 894 #endif
 895   msize = ntohs (hello->size);
 896   GNUNET_assert (size >= msize);
 897   memcpy (buf, hello, msize);
 898   GNUNET_free (hello);
 899   return msize;
 900 }
 901
 902
 903 /**
 904  * Offer the transport service the HELLO of another peer.  Note that
 905  * the transport service may just ignore this message if the HELLO is
 906  * malformed or useless due to our local configuration.
 907  *
 908  * @param handle connection to transport service
 909  * @param hello the hello message
 910  */
 911 void
 912 GNUNET_TRANSPORT_offer_hello (struct GNUNET_TRANSPORT_Handle *handle,
 913                               const struct GNUNET_MessageHeader *hello)
 914 {
 915   struct GNUNET_MessageHeader *hc;
 916   uint16_t size;
 917
 918   if (handle->client == NULL)
 919     {
 920 #if DEBUG_TRANSPORT
 921       GNUNET_log (GNUNET_ERROR_TYPE_INFO,
 922                   "Not connected to transport service, dropping offered HELLO\n");
 923 #endif
 924       return;
 925     }
 926   GNUNET_break (ntohs (hello->type) == GNUNET_MESSAGE_TYPE_HELLO);
 927   size = ntohs (hello->size);
 928   GNUNET_break (size >= sizeof (struct GNUNET_MessageHeader));
 929   hc = GNUNET_malloc (size);
 930   memcpy (hc, hello, size);
 931   schedule_control_transmit (handle,
 932                              size,
 933                              GNUNET_NO, OFFER_HELLO_TIMEOUT, &send_hello, hc);
 934 }
 935
 936
 937 /**
 938  * Function we use for handling incoming messages.
 939  */
 940 static void demultiplexer (void *cls, const struct GNUNET_MessageHeader *msg);
 941
 942
 943 static size_t
 944 send_start (void *cls, size_t size, void *buf)
 945 {
 946   struct GNUNET_MessageHeader *s = buf;
 947
 948   if (buf == NULL)
 949     {
 950 #if DEBUG_TRANSPORT
 951       GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 952                   "Timeout while trying to transmit `%s' request.\n",
 953                   "START");
 954 #endif
 955       return 0;
 956     }
 957 #if DEBUG_TRANSPORT
 958   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 959               "Transmitting `%s' request.\n", "START");
 960 #endif
 961   GNUNET_assert (size >= sizeof (struct GNUNET_MessageHeader));
 962   s->size = htons (sizeof (struct GNUNET_MessageHeader));
 963   s->type = htons (GNUNET_MESSAGE_TYPE_TRANSPORT_START);
 964   return sizeof (struct GNUNET_MessageHeader);
 965 }
 966
 967
 968 /**
 969  * We're ready to transmit the request that the transport service
 970  * should connect to a new peer.  In addition to sending the
 971  * request, schedule the next phase for the transmission processing
 972  * that caused the connect request in the first place.
 973  */
 974 static size_t
 975 request_connect (void *cls, size_t size, void *buf)
 976 {
 977   struct GNUNET_TRANSPORT_TransmitHandle *th = cls;
 978   struct TryConnectMessage *tcm;
 979   struct GNUNET_TRANSPORT_Handle *h;
 980
 981   GNUNET_assert (th->notify_delay_task == GNUNET_SCHEDULER_NO_TASK);
 982   h = th->handle;
 983   if (buf == NULL)
 984     {
 985 #if DEBUG_TRANSPORT
 986       GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 987                   "Failed to transmit `%s' request for `%4s' to service.\n",
 988                   "TRY_CONNECT", GNUNET_i2s (&th->target));
 989 #endif
 990       if (th->notify_delay_task != GNUNET_SCHEDULER_NO_TASK)
 991         {
 992           GNUNET_SCHEDULER_cancel (h->sched, th->notify_delay_task);
 993           th->notify_delay_task = GNUNET_SCHEDULER_NO_TASK;
 994         }
 995       th->notify (th->notify_cls, 0, NULL);
 996       GNUNET_free (th);
 997       return 0;
 998     }
 999 #if DEBUG_TRANSPORT
1000   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1001               "Transmitting `%s' message for `%4s' (need connection in %llu ms).\n",
1002               "TRY_CONNECT", GNUNET_i2s (&th->target),
1003               GNUNET_TIME_absolute_get_remaining (th->timeout).value);
1004 #endif
1005   GNUNET_assert (size >= sizeof (struct TryConnectMessage));
1006   tcm = buf;
1007   tcm->header.size = htons (sizeof (struct TryConnectMessage));
1008   tcm->header.type = htons (GNUNET_MESSAGE_TYPE_TRANSPORT_TRY_CONNECT);
1009   tcm->reserved = htonl (0);
1010   memcpy (&tcm->peer, &th->target, sizeof (struct GNUNET_PeerIdentity));
1011   th->notify_delay_task
1012     = GNUNET_SCHEDULER_add_delayed (h->sched,
1013                                     GNUNET_TIME_absolute_get_remaining
1014                                     (th->timeout),
1015                                     &peer_transmit_timeout, th);
1016   insert_transmit_handle (&h->connect_wait_head, th);
1017   return sizeof (struct TryConnectMessage);
1018 }
1019
1020
1021 /**
1022  * Schedule a request to connect to the given
1023  * neighbour (and if successful, add the specified
1024  * handle to the wait list).
1025  *
1026  * @param th handle for a request to transmit once we
1027  *        have connected
1028  */
1029 static void
1030 try_connect (struct GNUNET_TRANSPORT_TransmitHandle *th)
1031 {
1032   GNUNET_assert (th->notify_delay_task == GNUNET_SCHEDULER_NO_TASK);
1033   schedule_control_transmit (th->handle,
1034                              sizeof (struct TryConnectMessage),
1035                              GNUNET_NO,
1036                              GNUNET_TIME_absolute_get_remaining (th->timeout),
1037                              &request_connect, th);
1038 }
1039
1040
1041 /**
1042  * Task for delayed attempts to reconnect to a peer.
1043  *
1044  * @param cls must be a transmit handle that determines the peer
1045  *        to which we will try to connect
1046  * @param tc scheduler information about why we were triggered (not used)
1047  */
1048 static void
1049 try_connect_task (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
1050 {
1051   struct GNUNET_TRANSPORT_TransmitHandle *th = cls;
1052
1053   th->notify_delay_task = GNUNET_SCHEDULER_NO_TASK;
1054   try_connect (th);
1055 }
1056
1057
1058 /**
1059  * Remove neighbour from our list.  Will automatically
1060  * trigger a re-connect attempt if we have messages pending
1061  * for this peer.
1062  *
1063  * @param h our state
1064  * @param peer the peer to remove
1065  */
1066 static void
1067 remove_neighbour (struct GNUNET_TRANSPORT_Handle *h,
1068                   const struct GNUNET_PeerIdentity *peer)
1069 {
1070   struct NeighbourList *prev;
1071   struct NeighbourList *pos;
1072   struct GNUNET_TRANSPORT_TransmitHandle *th;
1073
1074 #if DEBUG_TRANSPORT
1075   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1076               "Removing neighbour `%s' from list of connected peers.\n",
1077               GNUNET_i2s (peer));
1078 #endif
1079   prev = NULL;
1080   pos = h->neighbours;
1081   while ((pos != NULL) &&
1082          (0 != memcmp (peer, &pos->id, sizeof (struct GNUNET_PeerIdentity))))
1083     {
1084       prev = pos;
1085       pos = pos->next;
1086     }
1087   if (pos == NULL)
1088     {
1089       GNUNET_break (0);
1090       return;
1091     }
1092   if (prev == NULL)
1093     h->neighbours = pos->next;
1094   else
1095     prev->next = pos->next;
1096   if (NULL != (th = pos->transmit_handle))
1097     {
1098       pos->transmit_handle = NULL;
1099       th->neighbour = NULL;
1100       remove_from_any_list (th);
1101       if (GNUNET_TIME_absolute_get_remaining (th->timeout).value <=
1102           CONNECT_RETRY_TIMEOUT.value)
1103         {
1104           /* signal error */
1105           GNUNET_log (GNUNET_ERROR_TYPE_INFO,
1106                       _
1107                       ("Connection with `%4s' failed and timeout was in the past, giving up on message delivery.\n"),
1108                       GNUNET_i2s (peer));
1109           GNUNET_assert (GNUNET_SCHEDULER_NO_TASK == th->notify_delay_task);
1110           peer_transmit_timeout (th, NULL);
1111         }
1112       else
1113         {
1114           GNUNET_log (GNUNET_ERROR_TYPE_INFO,
1115                       _
1116                       ("Connection with `%4s' failed, will keep trying for %llu ms to deliver message\n"),
1117                       GNUNET_i2s (peer),
1118                       GNUNET_TIME_absolute_get_remaining (th->timeout).value);
1119           /* try again in a bit */
1120           GNUNET_assert (GNUNET_SCHEDULER_NO_TASK == th->notify_delay_task);
1121           th->notify_delay_task
1122             = GNUNET_SCHEDULER_add_delayed (h->sched,
1123                                             CONNECT_RETRY_TIMEOUT,
1124                                             &try_connect_task, th);
1125         }
1126     }
1127   if (h->nc_cb != NULL)
1128     h->nd_cb (h->cls, peer);
1129   GNUNET_free (pos);
1130 }
1131
1132
1133 /**
1134  * Try again to connect to transport service.
1135  */
1136 static void
1137 reconnect (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
1138 {
1139   struct GNUNET_TRANSPORT_Handle *h = cls;
1140   struct GNUNET_TRANSPORT_TransmitHandle *pos;
1141   struct NeighbourList *n;
1142
1143   /* Forget about all neighbours that we used to be connected
1144      to */
1145   while (NULL != (n = h->neighbours))
1146     remove_neighbour (h, &n->id);
1147 #if DEBUG_TRANSPORT
1148   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Connecting to transport service.\n");
1149 #endif
1150   GNUNET_assert (h->client == NULL);
1151   h->reconnect_task = GNUNET_SCHEDULER_NO_TASK;
1152   h->client = GNUNET_CLIENT_connect (h->sched, "transport", h->cfg);
1153   GNUNET_assert (h->client != NULL);
1154   /* make sure we don't send "START" twice,
1155      remove existing entry from queue (if present) */
1156   pos = h->connect_ready_head;
1157   while (pos != NULL)
1158     {
1159       if (pos->notify == &send_start)
1160         {
1161           if (pos->prev == NULL)
1162             h->connect_ready_head = pos->next;
1163           else
1164             pos->prev->next = pos->next;
1165           if (pos->next != NULL)
1166             pos->next->prev = pos->prev;
1167           GNUNET_assert (pos->neighbour == NULL);
1168           if (GNUNET_SCHEDULER_NO_TASK != pos->notify_delay_task)
1169             {
1170               GNUNET_SCHEDULER_cancel (h->sched, pos->notify_delay_task);
1171               pos->notify_delay_task = GNUNET_SCHEDULER_NO_TASK;
1172             }
1173           GNUNET_free (pos);
1174           break;
1175         }
1176       pos = pos->next;
1177     }
1178   schedule_control_transmit (h,
1179                              sizeof (struct GNUNET_MessageHeader),
1180                              GNUNET_YES,
1181                              GNUNET_TIME_UNIT_FOREVER_REL, &send_start, NULL);
1182   GNUNET_CLIENT_receive (h->client,
1183                          &demultiplexer, h, GNUNET_TIME_UNIT_FOREVER_REL);
1184 }
1185
1186
1187 /**
1188  * Function that will schedule the job that will try
1189  * to connect us again to the client.
1190  */
1191 static void
1192 schedule_reconnect (struct GNUNET_TRANSPORT_Handle *h)
1193 {
1194 #if DEBUG_TRANSPORT
1195   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1196               "Scheduling task to reconnect to transport service in %llu ms.\n",
1197               h->reconnect_delay.value);
1198 #endif
1199   GNUNET_assert (h->client == NULL);
1200   GNUNET_assert (h->reconnect_task == GNUNET_SCHEDULER_NO_TASK);
1201   h->reconnect_task
1202     = GNUNET_SCHEDULER_add_delayed (h->sched,
1203                                     h->reconnect_delay, &reconnect, h);
1204   h->reconnect_delay = GNUNET_TIME_UNIT_SECONDS;
1205 }
1206
1207
1208 /**
1209  * We are connected to the respective peer, check the
1210  * bandwidth limits and schedule the transmission.
1211  */
1212 static void schedule_request (struct GNUNET_TRANSPORT_TransmitHandle *th);
1213
1214
1215 /**
1216  * Function called by the scheduler when the timeout
1217  * for bandwidth availablility for the target
1218  * neighbour is reached.
1219  */
1220 static void
1221 transmit_ready (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
1222 {
1223   struct GNUNET_TRANSPORT_TransmitHandle *th = cls;
1224
1225   th->notify_delay_task = GNUNET_SCHEDULER_NO_TASK;
1226   schedule_request (th);
1227 }
1228
1229
1230 /**
1231  * Remove the given transmit handle from the wait list.  Does NOT free
1232  * it.
1233  */
1234 static void
1235 remove_from_wait_list (struct GNUNET_TRANSPORT_TransmitHandle *th)
1236 {
1237   if (th->prev == NULL)
1238     th->handle->connect_wait_head = th->next;
1239   else
1240     th->prev->next = th->next;
1241   if (th->next != NULL)
1242     th->next->prev = th->prev;
1243 }
1244
1245
1246 /**
1247  * We are connected to the respective peer, check the
1248  * bandwidth limits and schedule the transmission.
1249  */
1250 static void
1251 schedule_request (struct GNUNET_TRANSPORT_TransmitHandle *th)
1252 {
1253   struct GNUNET_TRANSPORT_Handle *h;
1254   struct GNUNET_TIME_Relative duration;
1255   struct NeighbourList *n;
1256   uint64_t available;
1257
1258   h = th->handle;
1259   n = th->neighbour;
1260   if (th->notify_delay_task != GNUNET_SCHEDULER_NO_TASK)
1261     {
1262       GNUNET_SCHEDULER_cancel (h->sched, th->notify_delay_task);
1263       th->notify_delay_task = GNUNET_SCHEDULER_NO_TASK;
1264     }
1265   /* check outgoing quota */
1266   duration = GNUNET_TIME_absolute_get_duration (n->last_quota_update);
1267   if (duration.value > MIN_QUOTA_REFRESH_TIME)
1268     {
1269       update_quota (n);
1270       duration = GNUNET_TIME_absolute_get_duration (n->last_quota_update);
1271     }
1272   available = duration.value * n->quota_out;
1273   if (available < n->last_sent + th->notify_size)
1274     {
1275       /* calculate how much bandwidth we'd still need to
1276          accumulate and based on that how long we'll have
1277          to wait... */
1278       available = n->last_sent + th->notify_size - available;
1279       duration = GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_MILLISECONDS,
1280                                                 available / n->quota_out);
1281       if (th->timeout.value <
1282           GNUNET_TIME_relative_to_absolute (duration).value)
1283         {
1284           /* signal timeout! */
1285 #if DEBUG_TRANSPORT
1286           GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1287                       "Would need %llu ms before bandwidth is available for delivery to `%4s', that is too long.  Signaling timeout.\n",
1288                       duration.value, GNUNET_i2s (&th->target));
1289 #endif
1290           remove_from_wait_list (th);
1291           th->notify (th->notify_cls, 0, NULL);
1292           GNUNET_free (th);
1293           return;
1294         }
1295 #if DEBUG_TRANSPORT
1296       GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1297                   "Need more bandwidth, delaying delivery to `%4s' by %llu ms\n",
1298                   GNUNET_i2s (&th->target), duration.value);
1299 #endif
1300       th->notify_delay_task
1301         = GNUNET_SCHEDULER_add_delayed (h->sched,
1302                                         duration, &transmit_ready, th);
1303       return;
1304     }
1305 #if DEBUG_TRANSPORT
1306   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1307               "Bandwidth available for transmission to `%4s'\n",
1308               GNUNET_i2s (&n->id));
1309 #endif
1310   if (GNUNET_NO == n->transmit_ok)
1311     {
1312       /* we may be ready, but transport service is not;
1313          wait for SendOkMessage or timeout */
1314 #if DEBUG_TRANSPORT
1315       GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1316                   "Need to wait for transport service `%s' message\n",
1317                   "SEND_OK");
1318 #endif
1319       th->notify_delay_task
1320         = GNUNET_SCHEDULER_add_delayed (h->sched,
1321                                         GNUNET_TIME_absolute_get_remaining
1322                                         (th->timeout), &peer_transmit_timeout,
1323                                         th);
1324       return;
1325     }
1326   n->transmit_ok = GNUNET_NO;
1327   remove_from_wait_list (th);
1328 #if DEBUG_TRANSPORT
1329   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1330               "Moving message for `%4s' to ready list\n",
1331               GNUNET_i2s (&n->id));
1332 #endif
1333   insert_transmit_handle (&h->connect_ready_head, th);
1334   if (GNUNET_NO == h->transmission_scheduled)
1335     schedule_transmission (h);
1336 }
1337
1338
1339 /**
1340  * Add neighbour to our list
1341  */
1342 static void
1343 add_neighbour (struct GNUNET_TRANSPORT_Handle *h,
1344                uint32_t quota_out,
1345                struct GNUNET_TIME_Relative latency,
1346                const struct GNUNET_PeerIdentity *pid)
1347 {
1348   struct NeighbourList *n;
1349   struct GNUNET_TRANSPORT_TransmitHandle *prev;
1350   struct GNUNET_TRANSPORT_TransmitHandle *pos;
1351   struct GNUNET_TRANSPORT_TransmitHandle *next;
1352
1353   /* check for duplicates */
1354   if (NULL != find_neighbour (h, pid))
1355     {
1356       GNUNET_break (0);
1357       return;
1358     }
1359 #if DEBUG_TRANSPORT
1360   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1361               "Creating entry for new neighbour `%4s'.\n", GNUNET_i2s (pid));
1362 #endif
1363   n = GNUNET_malloc (sizeof (struct NeighbourList));
1364   n->id = *pid;
1365   n->last_quota_update = GNUNET_TIME_absolute_get ();
1366   n->quota_out = quota_out;
1367   n->next = h->neighbours;
1368   n->transmit_ok = GNUNET_YES;
1369   h->neighbours = n;
1370   if (h->nc_cb != NULL)
1371     h->nc_cb (h->cls, &n->id, latency);
1372   prev = NULL;
1373   pos = h->connect_wait_head;
1374   while (pos != NULL)
1375     {
1376       next = pos->next;
1377       if (0 == memcmp (pid,
1378                        &pos->target, sizeof (struct GNUNET_PeerIdentity)))
1379         {
1380           pos->neighbour = n;
1381           GNUNET_assert (NULL == n->transmit_handle);
1382           n->transmit_handle = pos;
1383           if (prev == NULL)
1384             h->connect_wait_head = next;
1385           else
1386             prev->next = next;
1387           if (GNUNET_YES == n->received_ack)
1388             {
1389 #if DEBUG_TRANSPORT
1390               GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1391                           "Found pending request for `%4s' will trigger it now.\n",
1392                           GNUNET_i2s (&pos->target));
1393 #endif
1394               if (pos->notify_delay_task != GNUNET_SCHEDULER_NO_TASK)
1395                 {
1396                   GNUNET_SCHEDULER_cancel (h->sched, pos->notify_delay_task);
1397                   pos->notify_delay_task = GNUNET_SCHEDULER_NO_TASK;
1398                 }
1399               schedule_request (pos);
1400             }
1401           else
1402             {
1403 #if DEBUG_TRANSPORT
1404               GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1405                           "Found pending request for `%4s' but still need `%s' before proceeding.\n",
1406                           GNUNET_i2s (&pos->target), "ACK");
1407 #endif
1408             }
1409           break;
1410         }
1411       prev = pos;
1412       pos = next;
1413     }
1414 }
1415
1416
1417 /**
1418  * Connect to the transport service.  Note that the connection may
1419  * complete (or fail) asynchronously.
1420  *
1421
1422  * @param sched scheduler to use
1423  * @param cfg configuration to use
1424  * @param cls closure for the callbacks
1425  * @param rec receive function to call
1426  * @param nc function to call on connect events
1427  * @param nd function to call on disconnect events
1428  */
1429 struct GNUNET_TRANSPORT_Handle *
1430 GNUNET_TRANSPORT_connect (struct GNUNET_SCHEDULER_Handle *sched,
1431                           const struct GNUNET_CONFIGURATION_Handle *cfg,
1432                           void *cls,
1433                           GNUNET_TRANSPORT_ReceiveCallback rec,
1434                           GNUNET_TRANSPORT_NotifyConnect nc,
1435                           GNUNET_TRANSPORT_NotifyDisconnect nd)
1436 {
1437   struct GNUNET_TRANSPORT_Handle *ret;
1438
1439   GNUNET_ARM_start_services (cfg, sched, "peerinfo", "transport", NULL);
1440   ret = GNUNET_malloc (sizeof (struct GNUNET_TRANSPORT_Handle));
1441   ret->sched = sched;
1442   ret->cfg = cfg;
1443   ret->cls = cls;
1444   ret->rec = rec;
1445   ret->nc_cb = nc;
1446   ret->nd_cb = nd;
1447   ret->reconnect_delay = GNUNET_TIME_UNIT_ZERO;
1448   schedule_reconnect (ret);
1449   return ret;
1450 }
1451
1452
1453 /**
1454  * Disconnect from the transport service.
1455  */
1456 void
1457 GNUNET_TRANSPORT_disconnect (struct GNUNET_TRANSPORT_Handle *handle)
1458 {
1459   struct GNUNET_TRANSPORT_TransmitHandle *th;
1460   struct NeighbourList *n;
1461   struct HelloWaitList *hwl;
1462   struct GNUNET_CLIENT_Connection *client;
1463
1464 #if DEBUG_TRANSPORT
1465   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Transport disconnect called!\n");
1466 #endif
1467   while (NULL != (th = handle->connect_ready_head))
1468     {
1469       handle->connect_ready_head = th->next;
1470       if (th->notify_delay_task != GNUNET_SCHEDULER_NO_TASK)
1471         {
1472           GNUNET_SCHEDULER_cancel (handle->sched, th->notify_delay_task);
1473           th->notify_delay_task = GNUNET_SCHEDULER_NO_TASK;
1474         }
1475       th->notify (th->notify_cls, 0, NULL);
1476       GNUNET_free (th);
1477     }
1478   while (NULL != (th = handle->connect_wait_head))
1479     {
1480       handle->connect_wait_head = th->next;
1481       if (th->notify_delay_task != GNUNET_SCHEDULER_NO_TASK)
1482         {
1483           GNUNET_SCHEDULER_cancel (handle->sched, th->notify_delay_task);
1484           th->notify_delay_task = GNUNET_SCHEDULER_NO_TASK;
1485         }
1486       th->notify (th->notify_cls, 0, NULL);
1487       GNUNET_free (th);
1488     }
1489   while (NULL != (n = handle->neighbours))
1490     {
1491       handle->neighbours = n->next;
1492       if (NULL != (th = n->transmit_handle))
1493         {
1494           if (th->notify_delay_task != GNUNET_SCHEDULER_NO_TASK)
1495             {
1496               GNUNET_SCHEDULER_cancel (handle->sched, th->notify_delay_task);
1497               th->notify_delay_task = GNUNET_SCHEDULER_NO_TASK;
1498             }
1499           th->notify (th->notify_cls, 0, NULL);
1500           GNUNET_free (th);
1501         }
1502       GNUNET_free (n);
1503     }
1504   while (NULL != (hwl = handle->hwl_head))
1505     {
1506       handle->hwl_head = hwl->next;
1507       GNUNET_SCHEDULER_cancel (handle->sched, hwl->task);
1508       GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
1509                   _
1510                   ("Disconnect while trying to obtain `%s' from transport service.\n"),
1511                   "HELLO");
1512       if (hwl->rec != NULL)
1513         hwl->rec (hwl->rec_cls, GNUNET_TIME_UNIT_ZERO, NULL, NULL);
1514       GNUNET_free (hwl);
1515     }
1516   if (handle->reconnect_task != GNUNET_SCHEDULER_NO_TASK)
1517     {
1518       GNUNET_SCHEDULER_cancel (handle->sched, handle->reconnect_task);
1519       handle->reconnect_task = GNUNET_SCHEDULER_NO_TASK;
1520     }
1521   GNUNET_free_non_null (handle->my_hello);
1522   handle->my_hello = NULL;
1523   GNUNET_ARM_stop_services (handle->cfg, handle->sched, "transport",
1524                             "peerinfo", NULL);
1525   if (NULL != handle->network_handle)
1526     {
1527       GNUNET_CLIENT_notify_transmit_ready_cancel (handle->network_handle);
1528       handle->network_handle = NULL;
1529     }
1530   if (NULL != (client = handle->client))
1531     {
1532 #if DEBUG_TRANSPORT
1533       GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1534                   "Disconnecting from transport service for good.\n");
1535 #endif
1536       handle->client = NULL;
1537       GNUNET_CLIENT_disconnect (client);
1538     }
1539   GNUNET_free (handle);
1540 }
1541
1542
1543 /**
1544  * Type of a function to call when we receive a message
1545  * from the service.
1546  *
1547  * @param cls closure
1548  * @param msg message received, NULL on timeout or fatal error
1549  */
1550 static void
1551 demultiplexer (void *cls, const struct GNUNET_MessageHeader *msg)
1552 {
1553   struct GNUNET_TRANSPORT_Handle *h = cls;
1554   const struct DisconnectInfoMessage *dim;
1555   const struct ConnectInfoMessage *cim;
1556   const struct InboundMessage *im;
1557   const struct GNUNET_MessageHeader *imm;
1558   const struct SendOkMessage *okm;
1559   struct HelloWaitList *hwl;
1560   struct NeighbourList *n;
1561   struct GNUNET_PeerIdentity me;
1562   struct GNUNET_TRANSPORT_TransmitHandle *th;
1563   uint16_t size;
1564
1565   if ((msg == NULL) || (h->client == NULL))
1566     {
1567       if (h->client != NULL)
1568         {
1569 #if DEBUG_TRANSPORT
1570           GNUNET_log (GNUNET_ERROR_TYPE_INFO,
1571                       "Error receiving from transport service, disconnecting temporarily.\n");
1572 #endif
1573           if (h->network_handle != NULL)
1574             {
1575               GNUNET_CLIENT_notify_transmit_ready_cancel (h->network_handle);
1576               h->network_handle = NULL;
1577               h->transmission_scheduled = GNUNET_NO;
1578               th = h->connect_ready_head;
1579               /* add timeout again, we cancelled the transmit_ready task! */
1580               GNUNET_assert (th->notify_delay_task ==
1581                              GNUNET_SCHEDULER_NO_TASK);
1582               th->notify_delay_task =
1583                 GNUNET_SCHEDULER_add_delayed (h->sched,
1584                                               GNUNET_TIME_absolute_get_remaining
1585                                               (th->timeout),
1586                                               &peer_transmit_timeout, th);
1587             }
1588           GNUNET_CLIENT_disconnect (h->client);
1589           h->client = NULL;
1590           schedule_reconnect (h);
1591         }
1592       else
1593         {
1594           /* shutdown initiated from 'GNUNET_TRANSPORT_disconnect',
1595              finish clean up work! */
1596           GNUNET_free (h);
1597         }
1598       return;
1599     }
1600   GNUNET_CLIENT_receive (h->client,
1601                          &demultiplexer, h, GNUNET_TIME_UNIT_FOREVER_REL);
1602   size = ntohs (msg->size);
1603   switch (ntohs (msg->type))
1604     {
1605     case GNUNET_MESSAGE_TYPE_HELLO:
1606       if (GNUNET_OK !=
1607           GNUNET_HELLO_get_id ((const struct GNUNET_HELLO_Message *) msg,
1608                                &me))
1609         {
1610           GNUNET_break (0);
1611           break;
1612         }
1613 #if DEBUG_TRANSPORT
1614       GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1615                   "Receiving (my own) `%s' message, I am `%4s'.\n",
1616                   "HELLO", GNUNET_i2s (&me));
1617 #endif
1618       GNUNET_free_non_null (h->my_hello);
1619       h->my_hello = NULL;
1620       if (size < sizeof (struct GNUNET_MessageHeader))
1621         {
1622           GNUNET_break (0);
1623           break;
1624         }
1625       h->my_hello = GNUNET_malloc (size);
1626       memcpy (h->my_hello, msg, size);
1627       while (NULL != (hwl = h->hwl_head))
1628         {
1629           h->hwl_head = hwl->next;
1630           GNUNET_SCHEDULER_cancel (h->sched, hwl->task);
1631           GNUNET_TRANSPORT_get_hello (h,
1632                                       GNUNET_TIME_UNIT_ZERO,
1633                                       hwl->rec, hwl->rec_cls);
1634           GNUNET_free (hwl);
1635         }
1636       break;
1637     case GNUNET_MESSAGE_TYPE_TRANSPORT_CONNECT:
1638       if (size != sizeof (struct ConnectInfoMessage))
1639         {
1640           GNUNET_break (0);
1641           break;
1642         }
1643       cim = (const struct ConnectInfoMessage *) msg;
1644 #if DEBUG_TRANSPORT
1645       GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1646                   "Receiving `%s' message for `%4s'.\n",
1647                   "CONNECT", GNUNET_i2s (&cim->id));
1648 #endif
1649       add_neighbour (h,
1650                      ntohl (cim->quota_out),
1651                      GNUNET_TIME_relative_ntoh (cim->latency), &cim->id);
1652       break;
1653     case GNUNET_MESSAGE_TYPE_TRANSPORT_DISCONNECT:
1654       if (size != sizeof (struct DisconnectInfoMessage))
1655         {
1656           GNUNET_break (0);
1657           break;
1658         }
1659       dim = (const struct DisconnectInfoMessage *) msg;
1660 #if DEBUG_TRANSPORT
1661       GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1662                   "Receiving `%s' message for `%4s'.\n",
1663                   "DISCONNECT", GNUNET_i2s (&dim->peer));
1664 #endif
1665       remove_neighbour (h, &dim->peer);
1666       break;
1667     case GNUNET_MESSAGE_TYPE_TRANSPORT_SEND_OK:
1668       if (size != sizeof (struct SendOkMessage))
1669         {
1670           GNUNET_break (0);
1671           break;
1672         }
1673       okm = (const struct SendOkMessage *) msg;
1674 #if DEBUG_TRANSPORT
1675       GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1676                   "Receiving `%s' message, transmission %s.\n", "SEND_OK",
1677                   ntohl (okm->success) == GNUNET_OK ? "succeeded" : "failed");
1678 #endif
1679       n = find_neighbour (h, &okm->peer);
1680       GNUNET_assert (n != NULL);
1681       n->transmit_ok = GNUNET_YES;
1682       if (n->transmit_handle != NULL)
1683         {
1684 #if DEBUG_TRANSPORT
1685           GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1686                       "Processing pending message for `%4s'\n",
1687                       GNUNET_i2s (&n->id));
1688 #endif
1689           GNUNET_SCHEDULER_cancel (h->sched,
1690                                    n->transmit_handle->notify_delay_task);
1691           n->transmit_handle->notify_delay_task = GNUNET_SCHEDULER_NO_TASK;
1692           GNUNET_assert (GNUNET_YES == n->received_ack);
1693           schedule_request (n->transmit_handle);
1694         }
1695       break;
1696     case GNUNET_MESSAGE_TYPE_TRANSPORT_RECV:
1697 #if DEBUG_TRANSPORT
1698       GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1699                   "Receiving `%s' message.\n", "RECV");
1700 #endif
1701       if (size <
1702           sizeof (struct InboundMessage) +
1703           sizeof (struct GNUNET_MessageHeader))
1704         {
1705           GNUNET_break (0);
1706           break;
1707         }
1708       im = (const struct InboundMessage *) msg;
1709       imm = (const struct GNUNET_MessageHeader *) &im[1];
1710       if (ntohs (imm->size) + sizeof (struct InboundMessage) != size)
1711         {
1712           GNUNET_break (0);
1713           break;
1714         }
1715       switch (ntohs (imm->type))
1716         {
1717         case GNUNET_MESSAGE_TYPE_TRANSPORT_ACK:
1718 #if DEBUG_TRANSPORT
1719           GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1720                       "Receiving `%s' message from `%4s'.\n",
1721                       "ACK", GNUNET_i2s (&im->peer));
1722 #endif
1723           n = find_neighbour (h, &im->peer);
1724           if (n == NULL)
1725             {
1726               GNUNET_break (0);
1727               break;
1728             }
1729           if (n->received_ack == GNUNET_NO)
1730             {
1731               n->received_ack = GNUNET_YES;
1732               if (NULL != n->transmit_handle)
1733                 {
1734 #if DEBUG_TRANSPORT
1735                   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1736                               "Peer connected, scheduling delayed message for deliverery now.\n");
1737 #endif
1738                   schedule_request (n->transmit_handle);
1739                 }
1740             }
1741           break;
1742         default:
1743 #if DEBUG_TRANSPORT
1744           GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1745                       "Received message of type %u from `%4s'.\n",
1746                       ntohs (imm->type), GNUNET_i2s (&im->peer));
1747 #endif
1748           if (h->rec != NULL)
1749             h->rec (h->cls,
1750                     GNUNET_TIME_relative_ntoh (im->latency), &im->peer, imm);
1751           break;
1752         }
1753       break;
1754     default:
1755       GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
1756                   _
1757                   ("Received unexpected message of type %u in %s:%u\n"),
1758                   ntohs (msg->type), __FILE__, __LINE__);
1759       GNUNET_break (0);
1760       break;
1761     }
1762 }
1763
1764
1765 struct ClientTransmitWrapper
1766 {
1767   GNUNET_CONNECTION_TransmitReadyNotify notify;
1768   void *notify_cls;
1769   struct GNUNET_TRANSPORT_TransmitHandle *th;
1770 };
1771
1772
1773 /**
1774  * Transmit message of a client destined for another
1775  * peer to the service.
1776  */
1777 static size_t
1778 client_notify_wrapper (void *cls, size_t size, void *buf)
1779 {
1780   struct ClientTransmitWrapper *ctw = cls;
1781   struct OutboundMessage *obm;
1782   struct GNUNET_MessageHeader *hdr;
1783   size_t ret;
1784
1785   if (size == 0)
1786     {
1787 #if DEBUG_TRANSPORT
1788       GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1789                   "Transmission request could not be satisfied.\n");
1790 #endif
1791       ret = ctw->notify (ctw->notify_cls, 0, NULL);
1792       GNUNET_assert (ret == 0);
1793       GNUNET_free (ctw);
1794       return 0;
1795     }
1796   GNUNET_assert (size >= sizeof (struct OutboundMessage));
1797   obm = buf;
1798   ret = ctw->notify (ctw->notify_cls,
1799                      size - sizeof (struct OutboundMessage),
1800                      (void *) &obm[1]);
1801   if (ret == 0)
1802     {
1803       /* Need to reset flag, no SEND means no SEND_OK! */
1804       ctw->th->neighbour->transmit_ok = GNUNET_YES;
1805       GNUNET_free (ctw);
1806       return 0;
1807     }
1808   GNUNET_assert (ret >= sizeof (struct GNUNET_MessageHeader));
1809   hdr = (struct GNUNET_MessageHeader *) &obm[1];
1810   GNUNET_assert (ntohs (hdr->size) == ret);
1811   GNUNET_assert (ret + sizeof (struct OutboundMessage) <
1812                  GNUNET_SERVER_MAX_MESSAGE_SIZE);
1813 #if DEBUG_TRANSPORT
1814   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1815               "Transmitting `%s' message with data for `%4s'\n",
1816               "SEND", GNUNET_i2s (&ctw->th->target));
1817 #endif
1818   ret += sizeof (struct OutboundMessage);
1819   obm->header.type = htons (GNUNET_MESSAGE_TYPE_TRANSPORT_SEND);
1820   obm->header.size = htons (ret);
1821   obm->priority = htonl (ctw->th->priority);
1822   obm->peer = ctw->th->target;
1823   GNUNET_free (ctw);
1824   return ret;
1825 }
1826
1827
1828
1829 /**
1830  * Check if we could queue a message of the given size for
1831  * transmission.  The transport service will take both its
1832  * internal buffers and bandwidth limits imposed by the
1833  * other peer into consideration when answering this query.
1834  *
1835  * @param handle connection to transport service
1836  * @param target who should receive the message
1837  * @param size how big is the message we want to transmit?
1838  * @param priority how important is the message?
1839  * @param timeout after how long should we give up (and call
1840  *        notify with buf NULL and size 0)?
1841  * @param notify function to call when we are ready to
1842  *        send such a message
1843  * @param notify_cls closure for notify
1844  * @return NULL if someone else is already waiting to be notified
1845  *         non-NULL if the notify callback was queued (can be used to cancel
1846  *         using GNUNET_TRANSPORT_notify_transmit_ready_cancel)
1847  */
1848 struct GNUNET_TRANSPORT_TransmitHandle *
1849 GNUNET_TRANSPORT_notify_transmit_ready (struct GNUNET_TRANSPORT_Handle
1850                                         *handle,
1851                                         const struct GNUNET_PeerIdentity
1852                                         *target, size_t size,
1853                                         unsigned int priority,
1854                                         struct GNUNET_TIME_Relative timeout,
1855                                         GNUNET_CONNECTION_TransmitReadyNotify
1856                                         notify, void *notify_cls)
1857 {
1858   struct GNUNET_TRANSPORT_TransmitHandle *pos;
1859   struct GNUNET_TRANSPORT_TransmitHandle *th;
1860   struct NeighbourList *n;
1861   struct ClientTransmitWrapper *ctw;
1862
1863   if (size + sizeof (struct OutboundMessage) >=
1864       GNUNET_SERVER_MAX_MESSAGE_SIZE)
1865     {
1866       GNUNET_break (0);
1867       return NULL;
1868     }
1869 #if DEBUG_TRANSPORT
1870   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1871               "Asking transport service for transmission of %u bytes to peer `%4s'.\n",
1872               size, GNUNET_i2s (target));
1873 #endif
1874   n = find_neighbour (handle, target);
1875   if ((n != NULL) && (n->transmit_handle != NULL))
1876     return NULL;                /* already have a request pending for this peer! */
1877   ctw = GNUNET_malloc (sizeof (struct ClientTransmitWrapper));
1878   th = GNUNET_malloc (sizeof (struct GNUNET_TRANSPORT_TransmitHandle));
1879   ctw->notify = notify;
1880   ctw->notify_cls = notify_cls;
1881   ctw->th = th;
1882   th->handle = handle;
1883   th->neighbour = n;
1884   th->target = *target;
1885   th->notify = &client_notify_wrapper;
1886   th->notify_cls = ctw;
1887   th->timeout = GNUNET_TIME_relative_to_absolute (timeout);
1888   th->notify_size = size + sizeof (struct OutboundMessage);
1889   th->priority = priority;
1890   if (NULL == n)
1891     {
1892       pos = handle->connect_wait_head;
1893       while (pos != NULL)
1894         {
1895           GNUNET_assert (0 != memcmp (target,
1896                                       &pos->target,
1897                                       sizeof (struct GNUNET_PeerIdentity)));
1898           pos = pos->next;
1899         }
1900 #if DEBUG_TRANSPORT
1901       GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1902                   "Will now try to connect to `%4s'.\n", GNUNET_i2s (target));
1903 #endif
1904       try_connect (th);
1905       return th;
1906     }
1907
1908 #if DEBUG_TRANSPORT
1909   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1910               "Transmission request queued for transmission to transport service.\n");
1911 #endif
1912   GNUNET_assert (NULL == n->transmit_handle);
1913   n->transmit_handle = th;
1914   if (GNUNET_YES != n->received_ack)
1915     {
1916 #if DEBUG_TRANSPORT
1917       GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1918                   "Connection to `%4s' is not yet confirmed connected, scheduling timeout (%llu ms) only.\n",
1919                   GNUNET_i2s (target), timeout.value);
1920 #endif
1921       th->notify_delay_task
1922         = GNUNET_SCHEDULER_add_delayed (handle->sched,
1923                                         timeout, &peer_transmit_timeout, th);
1924       return th;
1925     }
1926
1927 #if DEBUG_TRANSPORT
1928   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1929               "Peer `%4s' is ready to receive, scheduling message for delivery now.\n",
1930               GNUNET_i2s (target));
1931 #endif
1932   th->notify_delay_task
1933     = GNUNET_SCHEDULER_add_now (handle->sched, &transmit_ready, th);
1934   return th;
1935 }
1936
1937
1938 /**
1939  * Cancel the specified transmission-ready notification.
1940  */
1941 void
1942 GNUNET_TRANSPORT_notify_transmit_ready_cancel (struct
1943                                                GNUNET_TRANSPORT_TransmitHandle
1944                                                *th)
1945 {
1946   struct GNUNET_TRANSPORT_Handle *h;
1947
1948 #if DEBUG_TRANSPORT
1949   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1950               "Transmission request of %u bytes to `%4s' was cancelled.\n",
1951               th->notify_size - sizeof (struct OutboundMessage),
1952               GNUNET_i2s (&th->target));
1953 #endif
1954   GNUNET_assert (th->notify == &client_notify_wrapper);
1955   remove_from_any_list (th);
1956   h = th->handle;
1957   if ((h->connect_ready_head == NULL) && (h->network_handle != NULL))
1958     {
1959       GNUNET_CLIENT_notify_transmit_ready_cancel (h->network_handle);
1960       h->network_handle = NULL;
1961       h->transmission_scheduled = GNUNET_NO;
1962     }
1963   GNUNET_free (th->notify_cls);
1964   GNUNET_assert (th->notify_delay_task == GNUNET_SCHEDULER_NO_TASK);
1965   GNUNET_free (th);
1966 }
1967
1968
1969 /* end of transport_api.c */