src/transport/gnunet-service-transport_neighbours.c

   1 /*
   2      This file is part of GNUnet.
   3      (C) 2010,2011 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 3, 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/gnunet-service-transport_neighbours.c
  23  * @brief neighbour management
  24  * @author Christian Grothoff
  25  */
  26 #include "platform.h"
  27 #include "gnunet_ats_service.h"
  28 #include "gnunet-service-transport_neighbours.h"
  29 #include "gnunet-service-transport_plugins.h"
  30 #include "gnunet-service-transport_validation.h"
  31 #include "gnunet-service-transport.h"
  32 #include "gnunet_peerinfo_service.h"
  33 #include "gnunet_constants.h"
  34 #include "transport.h"
  35
  36
  37 /**
  38  * Size of the neighbour hash map.
  39  */
  40 #define NEIGHBOUR_TABLE_SIZE 256
  41
  42 /**
  43  * How often must a peer violate bandwidth quotas before we start
  44  * to simply drop its messages?
  45  */
  46 #define QUOTA_VIOLATION_DROP_THRESHOLD 10
  47
  48
  49 /**
  50  * Entry in neighbours.
  51  */
  52 struct NeighbourMapEntry;
  53
  54
  55 /**
  56  * For each neighbour we keep a list of messages
  57  * that we still want to transmit to the neighbour.
  58  */
  59 struct MessageQueue
  60 {
  61
  62   /**
  63    * This is a doubly linked list.
  64    */
  65   struct MessageQueue *next;
  66
  67   /**
  68    * This is a doubly linked list.
  69    */
  70   struct MessageQueue *prev;
  71
  72   /**
  73    * Once this message is actively being transmitted, which
  74    * neighbour is it associated with?
  75    */
  76   struct NeighbourMapEntry *n;
  77
  78   /**
  79    * Function to call once we're done.
  80    */
  81   GST_NeighbourSendContinuation cont;
  82
  83   /**
  84    * Closure for 'cont'
  85    */
  86   void *cont_cls;
  87
  88   /**
  89    * The message(s) we want to transmit, GNUNET_MessageHeader(s)
  90    * stuck together in memory.  Allocated at the end of this struct.
  91    */
  92   const char *message_buf;
  93
  94   /**
  95    * Size of the message buf
  96    */
  97   size_t message_buf_size;
  98
  99   /**
 100    * At what time should we fail?
 101    */
 102   struct GNUNET_TIME_Absolute timeout;
 103
 104 };
 105
 106
 107 /**
 108  * Entry in neighbours.
 109  */
 110 struct NeighbourMapEntry
 111 {
 112
 113   /**
 114    * Head of list of messages we would like to send to this peer;
 115    * must contain at most one message per client.
 116    */
 117   struct MessageQueue *messages_head;
 118
 119   /**
 120    * Tail of list of messages we would like to send to this peer; must
 121    * contain at most one message per client.
 122    */
 123   struct MessageQueue *messages_tail;
 124
 125   /**
 126    * Context for address suggestion.
 127    * NULL after we are connected.
 128    */
 129   struct GNUNET_ATS_SuggestionContext *asc;
 130
 131   /**
 132    * Performance data for the peer.
 133    */
 134   struct GNUNET_TRANSPORT_ATS_Information *ats;
 135
 136   /**
 137    * Are we currently trying to send a message? If so, which one?
 138    */
 139   struct MessageQueue *is_active;
 140
 141   /**
 142    * Active session for communicating with the peer.
 143    */
 144   struct Session *session;
 145
 146   /**
 147    * Name of the plugin we currently use.
 148    */
 149   char *plugin_name;
 150
 151   /**
 152    * Address used for communicating with the peer, NULL for inbound connections.
 153    */
 154   void *addr;
 155
 156   /**
 157    * Number of bytes in 'addr'.
 158    */
 159   size_t addrlen;
 160
 161   /**
 162    * Identity of this neighbour.
 163    */
 164   struct GNUNET_PeerIdentity id;
 165
 166   /**
 167    * ID of task scheduled to run when this peer is about to
 168    * time out (will free resources associated with the peer).
 169    */
 170   GNUNET_SCHEDULER_TaskIdentifier timeout_task;
 171
 172   /**
 173    * ID of task scheduled to run when we should try transmitting
 174    * the head of the message queue.
 175    */
 176   GNUNET_SCHEDULER_TaskIdentifier transmission_task;
 177
 178   /**
 179    * Tracker for inbound bandwidth.
 180    */
 181   struct GNUNET_BANDWIDTH_Tracker in_tracker;
 182
 183   /**
 184    * How often has the other peer (recently) violated the inbound
 185    * traffic limit?  Incremented by 10 per violation, decremented by 1
 186    * per non-violation (for each time interval).
 187    */
 188   unsigned int quota_violation_count;
 189
 190   /**
 191    * Number of values in 'ats' array.
 192    */
 193   unsigned int ats_count;
 194
 195   /**
 196    * Are we already in the process of disconnecting this neighbour?
 197    */
 198   int in_disconnect;
 199
 200   /**
 201    * Do we currently consider this neighbour connected? (as far as
 202    * the connect/disconnect callbacks are concerned)?
 203    */
 204   int is_connected;
 205
 206 };
 207
 208
 209 /**
 210  * All known neighbours and their HELLOs.
 211  */
 212 static struct GNUNET_CONTAINER_MultiHashMap *neighbours;
 213
 214 /**
 215  * Closure for connect_notify_cb and disconnect_notify_cb
 216  */
 217 static void *callback_cls;
 218
 219 /**
 220  * Function to call when we connected to a neighbour.
 221  */
 222 static GNUNET_TRANSPORT_NotifyConnect connect_notify_cb;
 223
 224 /**
 225  * Function to call when we disconnected from a neighbour.
 226  */
 227 static GNUNET_TRANSPORT_NotifyDisconnect disconnect_notify_cb;
 228
 229
 230 /**
 231  * Lookup a neighbour entry in the neighbours hash map.
 232  *
 233  * @param pid identity of the peer to look up
 234  * @return the entry, NULL if there is no existing record
 235  */
 236 static struct NeighbourMapEntry *
 237 lookup_neighbour (const struct GNUNET_PeerIdentity *pid)
 238 {
 239   return GNUNET_CONTAINER_multihashmap_get (neighbours,
 240                                             &pid->hashPubKey);
 241 }
 242
 243
 244 /**
 245  * Task invoked to start a transmission to another peer.
 246  *
 247  * @param cls the 'struct NeighbourMapEntry'
 248  * @param tc scheduler context
 249  */
 250 static void
 251 transmission_task (void *cls,
 252                    const struct GNUNET_SCHEDULER_TaskContext *tc);
 253
 254
 255 /**
 256  * We're done with our transmission attempt, continue processing.
 257  *
 258  * @param cls the 'struct MessageQueue' of the message
 259  * @param receiver intended receiver
 260  * @param success whether it worked or not
 261  */
 262 static void
 263 transmit_send_continuation (void *cls,
 264                             const struct GNUNET_PeerIdentity *receiver,
 265                             int success)
 266 {
 267   struct MessageQueue *mq;
 268   struct NeighbourMapEntry *n;
 269
 270   mq = cls;
 271   n = mq->n;
 272   if (NULL != n)
 273     {
 274       GNUNET_assert (n->is_active == mq);
 275       n->is_active = NULL;
 276       GNUNET_assert (n->transmission_task == GNUNET_SCHEDULER_NO_TASK);
 277       n->transmission_task = GNUNET_SCHEDULER_add_now (&transmission_task,
 278                                                        n);
 279     }
 280   if (NULL != mq->cont)
 281     mq->cont (mq->cont_cls,
 282               success);
 283   GNUNET_free (mq);
 284 }
 285
 286
 287 /**
 288  * Check the ready list for the given neighbour and if a plugin is
 289  * ready for transmission (and if we have a message), do so!
 290  *
 291  * @param neighbour target peer for which to transmit
 292  */
 293 static void
 294 try_transmission_to_peer (struct NeighbourMapEntry *n)
 295 {
 296   struct MessageQueue *mq;
 297   struct GNUNET_TIME_Relative timeout;
 298   ssize_t ret;
 299   struct GNUNET_TRANSPORT_PluginFunctions *papi;
 300
 301   if (n->is_active != NULL)
 302     return; /* transmission already pending */
 303   if (n->transmission_task != GNUNET_SCHEDULER_NO_TASK)
 304     return; /* currently waiting for bandwidth */
 305   mq = n->messages_head;
 306   while (NULL != (mq = n->messages_head))
 307     {
 308       timeout = GNUNET_TIME_absolute_get_remaining (mq->timeout);
 309       if (timeout.rel_value > 0)
 310         break;
 311       transmit_send_continuation (mq, &n->id, GNUNET_SYSERR); /* timeout */
 312     }
 313   if (NULL == mq)
 314     return; /* no more messages */
 315
 316   papi = GST_plugins_find (n->plugin_name);
 317   if (papi == NULL)
 318     {
 319       GNUNET_break (0);
 320       return;
 321     }
 322   GNUNET_CONTAINER_DLL_remove (n->messages_head,
 323                                n->messages_tail,
 324                                mq);
 325   n->is_active = mq;
 326   mq->n = n;
 327   ret = papi->send (papi->cls,
 328                     &n->id,
 329                     mq->message_buf,
 330                     mq->message_buf_size,
 331                     0 /* priority -- remove from plugin API? */,
 332                     timeout,
 333                     n->session,
 334                     n->addr,
 335                     n->addrlen,
 336                     GNUNET_YES,
 337                     &transmit_send_continuation, mq);
 338   if (ret == -1)
 339     {
 340       /* failure, but 'send' would not call continuation in this case,
 341          so we need to do it here! */
 342       transmit_send_continuation (mq,
 343                                   &n->id,
 344                                   GNUNET_SYSERR);
 345       n->transmission_task = GNUNET_SCHEDULER_add_now (&transmission_task,
 346                                                        n);
 347     }
 348 }
 349
 350
 351 /**
 352  * Task invoked to start a transmission to another peer.
 353  *
 354  * @param cls the 'struct NeighbourMapEntry'
 355  * @param tc scheduler context
 356  */
 357 static void
 358 transmission_task (void *cls,
 359                    const struct GNUNET_SCHEDULER_TaskContext *tc)
 360 {
 361   struct NeighbourMapEntry *n = cls;
 362
 363   n->transmission_task = GNUNET_SCHEDULER_NO_TASK;
 364   try_transmission_to_peer (n);
 365 }
 366
 367
 368 /**
 369  * Initialize the neighbours subsystem.
 370  *
 371  * @param cls closure for callbacks
 372  * @param connect_cb function to call if we connect to a peer
 373  * @param disconnect_cb function to call if we disconnect from a peer
 374  */
 375 void
 376 GST_neighbours_start (void *cls,
 377                       GNUNET_TRANSPORT_NotifyConnect connect_cb,
 378                       GNUNET_TRANSPORT_NotifyDisconnect disconnect_cb)
 379 {
 380   callback_cls = cls;
 381   connect_notify_cb = connect_cb;
 382   disconnect_notify_cb = disconnect_cb;
 383   neighbours = GNUNET_CONTAINER_multihashmap_create (NEIGHBOUR_TABLE_SIZE);
 384 }
 385
 386
 387 /**
 388  * Disconnect from the given neighbour, clean up the record.
 389  *
 390  * @param n neighbour to disconnect from
 391  */
 392 static void
 393 disconnect_neighbour (struct NeighbourMapEntry *n)
 394 {
 395   struct MessageQueue *mq;
 396
 397   if (GNUNET_YES == n->in_disconnect)
 398     return;
 399   n->in_disconnect = GNUNET_YES;
 400   while (NULL != (mq = n->messages_head))
 401     {
 402       GNUNET_CONTAINER_DLL_remove (n->messages_head,
 403                                    n->messages_tail,
 404                                    mq);
 405       mq->cont (mq->cont_cls, GNUNET_SYSERR);
 406       GNUNET_free (mq);
 407     }
 408   if (NULL != n->is_active)
 409     {
 410       n->is_active->n = NULL;
 411       n->is_active = NULL;
 412     }
 413   if (GNUNET_YES == n->is_connected)
 414     {
 415       n->is_connected = GNUNET_NO;
 416       disconnect_notify_cb (callback_cls,
 417                             &n->id);
 418     }
 419   GNUNET_assert (GNUNET_YES ==
 420                  GNUNET_CONTAINER_multihashmap_remove (neighbours,
 421                                                        &n->id.hashPubKey,
 422                                                        n));
 423   if (GNUNET_SCHEDULER_NO_TASK != n->timeout_task)
 424     {
 425       GNUNET_SCHEDULER_cancel (n->timeout_task);
 426       n->timeout_task = GNUNET_SCHEDULER_NO_TASK;
 427     }
 428   if (GNUNET_SCHEDULER_NO_TASK != n->transmission_task)
 429     {
 430       GNUNET_SCHEDULER_cancel (n->timeout_task);
 431       n->transmission_task = GNUNET_SCHEDULER_NO_TASK;
 432     }
 433   if (NULL != n->asc)
 434     {
 435       GNUNET_ATS_suggest_address_cancel (n->asc);
 436       n->asc = NULL;
 437     }
 438   GNUNET_array_grow (n->ats,
 439                      n->ats_count,
 440                      0);
 441   if (NULL != n->plugin_name)
 442     {
 443       GNUNET_free (n->plugin_name);
 444       n->plugin_name = NULL;
 445     }
 446   if (NULL != n->addr)
 447     {
 448       GNUNET_free (n->addr);
 449       n->addr = NULL;
 450       n->addrlen = 0;
 451     }
 452   n->session = NULL;
 453   GNUNET_free (n);
 454 }
 455
 456
 457 /**
 458  * Peer has been idle for too long. Disconnect.
 459  *
 460  * @param cls the 'struct NeighbourMapEntry' of the neighbour that went idle
 461  * @param tc scheduler context
 462  */
 463 static void
 464 neighbour_timeout_task (void *cls,
 465                         const struct GNUNET_SCHEDULER_TaskContext *tc)
 466 {
 467   struct NeighbourMapEntry *n = cls;
 468
 469   n->timeout_task = GNUNET_SCHEDULER_NO_TASK;
 470   disconnect_neighbour (n);
 471 }
 472
 473
 474 /**
 475  * Disconnect from the given neighbour.
 476  *
 477  * @param cls unused
 478  * @param key hash of neighbour's public key (not used)
 479  * @param value the 'struct NeighbourMapEntry' of the neighbour
 480  */
 481 static int
 482 disconnect_all_neighbours (void *cls,
 483                            const GNUNET_HashCode *key,
 484                            void *value)
 485 {
 486   struct NeighbourMapEntry *n = value;
 487
 488 #if DEBUG_TRANSPORT
 489   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 490               "Disconnecting peer `%4s', %s\n",
 491               GNUNET_i2s(&n->id),
 492               "SHUTDOWN_TASK");
 493 #endif
 494   disconnect_neighbour (n);
 495   return GNUNET_OK;
 496 }
 497
 498
 499 /**
 500  * Cleanup the neighbours subsystem.
 501  */
 502 void
 503 GST_neighbours_stop ()
 504 {
 505   GNUNET_CONTAINER_multihashmap_iterate (neighbours,
 506                                          &disconnect_all_neighbours,
 507                                          NULL);
 508   GNUNET_CONTAINER_multihashmap_destroy (neighbours);
 509   neighbours = NULL;
 510   callback_cls = NULL;
 511   connect_notify_cb = NULL;
 512   disconnect_notify_cb = NULL;
 513 }
 514
 515
 516 /**
 517  * A session was terminated. Take note.
 518  *
 519  * @param peer identity of the peer where the session died
 520  * @param session session that is gone
 521  */
 522 void
 523 GST_neighbours_session_terminated (const struct GNUNET_PeerIdentity *peer,
 524                                    struct Session *session)
 525 {
 526   struct NeighbourMapEntry *n;
 527
 528   n = lookup_neighbour (peer);
 529   if (NULL == n)
 530     return;
 531   if (session == n->session)
 532     n->session = NULL;
 533 }
 534
 535
 536 /**
 537  * For an existing neighbour record, set the active connection to
 538  * the given address.
 539  *
 540  * @param peer identity of the peer to switch the address for
 541  * @param plugin_name name of transport that delivered the PONG
 542  * @param address address of the other peer, NULL if other peer
 543  *                       connected to us
 544  * @param address_len number of bytes in address
 545  * @param session session to use (or NULL)
 546  * @param ats performance data
 547  * @param ats_count number of entries in ats (excluding 0-termination)
 548  */
 549 void
 550 GST_neighbours_switch_to_address (const struct GNUNET_PeerIdentity *peer,
 551                                   const char *plugin_name,
 552                                   const void *address,
 553                                   size_t address_len,
 554                                   struct Session *session,
 555                                   const struct GNUNET_TRANSPORT_ATS_Information *ats,
 556                                   uint32_t ats_count)
 557 {
 558   struct NeighbourMapEntry *n;
 559   struct GNUNET_MessageHeader connect_msg;
 560
 561   n = lookup_neighbour (peer);
 562   if (NULL == n)
 563     {
 564       GNUNET_break (0);
 565       return;
 566     }
 567   GNUNET_free_non_null (n->addr);
 568   n->addr = GNUNET_malloc (address_len);
 569   memcpy (n->addr, address, address_len);
 570   n->addrlen = address_len;
 571   n->session = session;
 572   GNUNET_array_grow (n->ats,
 573                      n->ats_count,
 574                      ats_count);
 575   memcpy (n->ats,
 576           ats,
 577           ats_count * sizeof (struct GNUNET_TRANSPORT_ATS_Information));
 578   GNUNET_free_non_null (n->plugin_name);
 579   n->plugin_name = GNUNET_strdup (plugin_name);
 580   GNUNET_SCHEDULER_cancel (n->timeout_task);
 581   n->timeout_task =
 582     GNUNET_SCHEDULER_add_delayed (GNUNET_CONSTANTS_IDLE_CONNECTION_TIMEOUT,
 583                                   &neighbour_timeout_task, n);
 584   connect_msg.size = htons (sizeof (struct GNUNET_MessageHeader));
 585   connect_msg.type = htons (GNUNET_MESSAGE_TYPE_TRANSPORT_CONNECT);
 586   GST_neighbours_send (peer,
 587                        &connect_msg,
 588                        sizeof (connect_msg),
 589                        GNUNET_TIME_UNIT_FOREVER_REL,
 590                        NULL, NULL);
 591 }
 592
 593
 594 /**
 595  * Try to connect to the target peer using the given address
 596  *
 597  * @param cls the 'struct NeighbourMapEntry' of the target
 598  * @param target identity of the target peer
 599  * @param plugin_name name of the plugin
 600  * @param plugin_address binary address
 601  * @param plugin_address_len length of address
 602  * @param bandwidth available bandwidth
 603  * @param ats performance data for the address (as far as known)
 604  * @param ats_count number of performance records in 'ats'
 605  */
 606 static void
 607 try_connect_using_address (void *cls,
 608                            const struct GNUNET_PeerIdentity *target,
 609                            const char *plugin_name,
 610                            const void *plugin_address,
 611                            size_t plugin_address_len,
 612                            struct GNUNET_BANDWIDTH_Value32NBO bandwidth,
 613                            const struct GNUNET_TRANSPORT_ATS_Information *ats,
 614                            uint32_t ats_count)
 615 {
 616   struct NeighbourMapEntry *n = cls;
 617
 618   n->asc = NULL;
 619   GST_neighbours_switch_to_address (target,
 620                                     plugin_name,
 621                                     plugin_address,
 622                                     plugin_address_len,
 623                                     NULL,
 624                                     ats, ats_count);
 625   if (GNUNET_YES == n->is_connected)
 626     return;
 627   n->is_connected = GNUNET_YES;
 628   connect_notify_cb (callback_cls,
 629                      target,
 630                      n->ats,
 631                      n->ats_count);
 632 }
 633
 634
 635 /**
 636  * Try to create a connection to the given target (eventually).
 637  *
 638  * @param target peer to try to connect to
 639  */
 640 void
 641 GST_neighbours_try_connect (const struct GNUNET_PeerIdentity *target)
 642 {
 643   struct NeighbourMapEntry *n;
 644
 645   GNUNET_assert (0 != memcmp (target,
 646                               &GST_my_identity,
 647                               sizeof (struct GNUNET_PeerIdentity)));
 648   n = lookup_neighbour (target);
 649   if ( (NULL != n) &&
 650        (GNUNET_YES == n->is_connected) )
 651     return; /* already connected */
 652   if (n == NULL)
 653     {
 654       n = GNUNET_malloc (sizeof (struct NeighbourMapEntry));
 655       n->id = *target;
 656       GNUNET_BANDWIDTH_tracker_init (&n->in_tracker,
 657                                      GNUNET_CONSTANTS_DEFAULT_BW_IN_OUT,
 658                                      MAX_BANDWIDTH_CARRY_S);
 659       n->timeout_task = GNUNET_SCHEDULER_add_delayed (GNUNET_CONSTANTS_IDLE_CONNECTION_TIMEOUT,
 660                                                       &neighbour_timeout_task, n);
 661       GNUNET_assert (GNUNET_OK ==
 662                      GNUNET_CONTAINER_multihashmap_put (neighbours,
 663                                                         &n->id.hashPubKey,
 664                                                         n,
 665                                                         GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_ONLY));
 666     }
 667   if (n->asc != NULL)
 668     return; /* already trying */
 669   n->asc = GNUNET_ATS_suggest_address (GST_ats,
 670                                        target,
 671                                        &try_connect_using_address,
 672                                        n);
 673 }
 674
 675
 676 /**
 677  * Test if we're connected to the given peer.
 678  *
 679  * @param target peer to test
 680  * @return GNUNET_YES if we are connected, GNUNET_NO if not
 681  */
 682 int
 683 GST_neighbours_test_connected (const struct GNUNET_PeerIdentity *target)
 684 {
 685   struct NeighbourMapEntry *n;
 686
 687   n = lookup_neighbour (target);
 688   if ( (NULL == n) ||
 689        (n->is_connected == GNUNET_YES) )
 690        return GNUNET_NO; /* not connected */
 691   return GNUNET_YES;
 692 }
 693
 694
 695 /**
 696  * Transmit a message to the given target using the active connection.
 697  *
 698  * @param target destination
 699  * @param msg message to send
 700  * @param msg_size number of bytes in msg
 701  * @param timeout when to fail with timeout
 702  * @param cont function to call when done
 703  * @param cont_cls closure for 'cont'
 704  */
 705 void
 706 GST_neighbours_send (const struct GNUNET_PeerIdentity *target,
 707                      const void *msg,
 708                      size_t msg_size,
 709                      struct GNUNET_TIME_Relative timeout,
 710                      GST_NeighbourSendContinuation cont,
 711                      void *cont_cls)
 712 {
 713   struct NeighbourMapEntry *n;
 714   struct MessageQueue *mq;
 715
 716   n = lookup_neighbour (target);
 717   if ( (n == NULL) ||
 718        (GNUNET_YES != n->is_connected) )
 719     {
 720       GNUNET_STATISTICS_update (GST_stats,
 721                                 gettext_noop ("# SET QUOTA messages ignored (no such peer)"),
 722                                 1,
 723                                 GNUNET_NO);
 724       if (NULL != cont)
 725         cont (cont_cls,
 726               GNUNET_SYSERR);
 727       return;
 728     }
 729   GNUNET_assert (msg_size >= sizeof (struct GNUNET_MessageHeader));
 730   GNUNET_STATISTICS_update (GST_stats,
 731                             gettext_noop ("# bytes in message queue for other peers"),
 732                             msg_size,
 733                             GNUNET_NO);
 734   mq = GNUNET_malloc (sizeof (struct MessageQueue) + msg_size);
 735   mq->cont = cont;
 736   mq->cont_cls = cont_cls;
 737   /* FIXME: this memcpy can be up to 7% of our total runtime! */
 738   memcpy (&mq[1], msg, msg_size);
 739   mq->message_buf = (const char*) &mq[1];
 740   mq->message_buf_size = msg_size;
 741   mq->timeout = GNUNET_TIME_relative_to_absolute (timeout);
 742   GNUNET_CONTAINER_DLL_insert_tail (n->messages_head,
 743                                     n->messages_tail,
 744                                     mq);
 745   if ( (GNUNET_SCHEDULER_NO_TASK == n->transmission_task) &&
 746        (NULL == n->is_active) )
 747     n->transmission_task = GNUNET_SCHEDULER_add_now (&transmission_task,
 748                                                      n);
 749 }
 750
 751
 752 /**
 753  * We have received a message from the given sender.  How long should
 754  * we delay before receiving more?  (Also used to keep the peer marked
 755  * as live).
 756  *
 757  * @param sender sender of the message
 758  * @param size size of the message
 759  * @return how long to wait before reading more from this sender
 760  */
 761 struct GNUNET_TIME_Relative
 762 GST_neighbours_calculate_receive_delay (const struct GNUNET_PeerIdentity *sender,
 763                                         ssize_t size)
 764 {
 765   struct NeighbourMapEntry *n;
 766   struct GNUNET_TIME_Relative ret;
 767
 768   n = lookup_neighbour (sender);
 769   if (n == NULL)
 770     return GNUNET_TIME_UNIT_ZERO;
 771   if (GNUNET_YES == GNUNET_BANDWIDTH_tracker_consume (&n->in_tracker,
 772                                                       size))
 773     {
 774       n->quota_violation_count++;
 775 #if DEBUG_TRANSPORT
 776       GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 777                   "Bandwidth quota (%u b/s) violation detected (total of %u).\n",
 778                   n->in_tracker.available_bytes_per_s__,
 779                   n->quota_violation_count);
 780 #endif
 781       /* Discount 32k per violation */
 782       GNUNET_BANDWIDTH_tracker_consume (&n->in_tracker,
 783                                         - 32 * 1024);
 784     }
 785   else
 786     {
 787       if (n->quota_violation_count > 0)
 788         {
 789           /* try to add 32k back */
 790           GNUNET_BANDWIDTH_tracker_consume (&n->in_tracker,
 791                                             32 * 1024);
 792           n->quota_violation_count--;
 793         }
 794     }
 795   GNUNET_SCHEDULER_cancel (n->timeout_task);
 796   n->timeout_task =
 797     GNUNET_SCHEDULER_add_delayed (GNUNET_CONSTANTS_IDLE_CONNECTION_TIMEOUT,
 798                                   &neighbour_timeout_task, n);
 799   if (n->quota_violation_count > QUOTA_VIOLATION_DROP_THRESHOLD)
 800     {
 801       GNUNET_STATISTICS_update (GST_stats,
 802                                 gettext_noop ("# bandwidth quota violations by other peers"),
 803                                 1,
 804                                 GNUNET_NO);
 805       return GNUNET_CONSTANTS_QUOTA_VIOLATION_TIMEOUT;
 806     }
 807   ret = GNUNET_BANDWIDTH_tracker_get_delay (&n->in_tracker, 0);
 808   if (ret.rel_value > 0)
 809     {
 810 #if DEBUG_TRANSPORT
 811       GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 812                   "Throttling read (%llu bytes excess at %u b/s), waiting %llu ms before reading more.\n",
 813                   (unsigned long long) n->in_tracker.consumption_since_last_update__,
 814                   (unsigned int) n->in_tracker.available_bytes_per_s__,
 815                   (unsigned long long) ret.rel_value);
 816 #endif
 817       GNUNET_STATISTICS_update (GST_stats,
 818                                 gettext_noop ("# ms throttling suggested"),
 819                                 (int64_t) ret.rel_value,
 820                                 GNUNET_NO);
 821     }
 822   return ret;
 823 }
 824
 825
 826 /**
 827  * Change the incoming quota for the given peer.
 828  *
 829  * @param neighbour identity of peer to change qutoa for
 830  * @param quota new quota
 831  */
 832 void
 833 GST_neighbours_set_incoming_quota (const struct GNUNET_PeerIdentity *neighbour,
 834                                    struct GNUNET_BANDWIDTH_Value32NBO quota)
 835 {
 836   struct NeighbourMapEntry *n;
 837
 838   n = lookup_neighbour (neighbour);
 839   if (n == NULL)
 840     {
 841       GNUNET_STATISTICS_update (GST_stats,
 842                                 gettext_noop ("# SET QUOTA messages ignored (no such peer)"),
 843                                 1,
 844                                 GNUNET_NO);
 845       return;
 846     }
 847   GNUNET_BANDWIDTH_tracker_update_quota (&n->in_tracker,
 848                                          quota);
 849   if (0 != ntohl (quota.value__))
 850     return;
 851 #if DEBUG_TRANSPORT
 852   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 853               "Disconnecting peer `%4s' due to `%s'\n",
 854               GNUNET_i2s(&n->id),
 855               "SET_QUOTA");
 856 #endif
 857   GNUNET_STATISTICS_update (GST_stats,
 858                             gettext_noop ("# disconnects due to quota of 0"),
 859                             1,
 860                             GNUNET_NO);
 861   disconnect_neighbour (n);
 862 }
 863
 864
 865 /**
 866  * Closure for the neighbours_iterate function.
 867  */
 868 struct IteratorContext
 869 {
 870   /**
 871    * Function to call on each connected neighbour.
 872    */
 873   GST_NeighbourIterator cb;
 874
 875   /**
 876    * Closure for 'cb'.
 877    */
 878   void *cb_cls;
 879 };
 880
 881
 882 /**
 883  * Call the callback from the closure for each connected neighbour.
 884  *
 885  * @param cls the 'struct IteratorContext'
 886  * @param key the hash of the public key of the neighbour
 887  * @param value the 'struct NeighbourMapEntry'
 888  * @return GNUNET_OK (continue to iterate)
 889  */
 890 static int
 891 neighbours_iterate (void *cls,
 892                     const GNUNET_HashCode *key,
 893                     void *value)
 894 {
 895   struct IteratorContext *ic = cls;
 896   struct NeighbourMapEntry *n = value;
 897
 898   if (GNUNET_YES != n->is_connected)
 899     return GNUNET_OK;
 900   GNUNET_assert (n->ats_count > 0);
 901   ic->cb (ic->cb_cls,
 902           &n->id,
 903           n->ats,
 904           n->ats_count - 1);
 905   return GNUNET_OK;
 906 }
 907
 908
 909 /**
 910  * Iterate over all connected neighbours.
 911  *
 912  * @param cb function to call
 913  * @param cb_cls closure for cb
 914  */
 915 void
 916 GST_neighbours_iterate (GST_NeighbourIterator cb,
 917                         void *cb_cls)
 918 {
 919   struct IteratorContext ic;
 920
 921   ic.cb = cb;
 922   ic.cb_cls = cb_cls;
 923   GNUNET_CONTAINER_multihashmap_iterate (neighbours,
 924                                          &neighbours_iterate,
 925                                          &ic);
 926 }
 927
 928
 929 /**
 930  * If we have an active connection to the given target, it must be shutdown.
 931  *
 932  * @param target peer to disconnect from
 933  */
 934 void
 935 GST_neighbours_force_disconnect (const struct GNUNET_PeerIdentity *target)
 936 {
 937   struct NeighbourMapEntry *n;
 938   struct GNUNET_TRANSPORT_PluginFunctions *papi;
 939   struct GNUNET_MessageHeader disconnect_msg;
 940
 941   n = lookup_neighbour (target);
 942   disconnect_msg.size = htons (sizeof (struct GNUNET_MessageHeader));
 943   disconnect_msg.type = htons (GNUNET_MESSAGE_TYPE_TRANSPORT_CONNECT);
 944   papi = GST_plugins_find (n->plugin_name);
 945   if (papi != NULL)
 946     papi->send (papi->cls,
 947                 target,
 948                 (const void*) &disconnect_msg,
 949                 sizeof (struct GNUNET_MessageHeader),
 950                 UINT32_MAX /* priority */,
 951                 GNUNET_TIME_UNIT_FOREVER_REL,
 952                 n->session,
 953                 n->addr,
 954                 n->addrlen,
 955                 GNUNET_YES,
 956                 NULL, NULL);
 957   disconnect_neighbour (n);
 958 }
 959
 960
 961 /* end of file gnunet-service-transport_neighbours.c */