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  * For an existing neighbour record, set the active connection to
 518  * the given address.
 519  *
 520  * @param plugin_name name of transport that delivered the PONG
 521  * @param address address of the other peer, NULL if other peer
 522  *                       connected to us
 523  * @param address_len number of bytes in address
 524  * @param ats performance data
 525  * @param ats_count number of entries in ats (excluding 0-termination)
 526  */
 527 void
 528 GST_neighbours_switch_to_address (const struct GNUNET_PeerIdentity *peer,
 529                                   const char *plugin_name,
 530                                   const void *address,
 531                                   size_t address_len,
 532                                   struct Session *session,
 533                                   const struct GNUNET_TRANSPORT_ATS_Information *ats,
 534                                   uint32_t ats_count)
 535 {
 536   struct NeighbourMapEntry *n;
 537   struct GNUNET_MessageHeader connect_msg;
 538
 539   n = lookup_neighbour (peer);
 540   if (NULL == n)
 541     {
 542       GNUNET_break (0);
 543       return;
 544     }
 545   GNUNET_free_non_null (n->addr);
 546   n->addr = GNUNET_malloc (address_len);
 547   memcpy (n->addr, address, address_len);
 548   n->addrlen = address_len;
 549   n->session = session;
 550   GNUNET_array_grow (n->ats,
 551                      n->ats_count,
 552                      ats_count);
 553   memcpy (n->ats,
 554           ats,
 555           ats_count * sizeof (struct GNUNET_TRANSPORT_ATS_Information));
 556   GNUNET_free_non_null (n->plugin_name);
 557   n->plugin_name = GNUNET_strdup (plugin_name);
 558   GNUNET_SCHEDULER_cancel (n->timeout_task);
 559   n->timeout_task =
 560     GNUNET_SCHEDULER_add_delayed (GNUNET_CONSTANTS_IDLE_CONNECTION_TIMEOUT,
 561                                   &neighbour_timeout_task, n);
 562   connect_msg.size = htons (sizeof (struct GNUNET_MessageHeader));
 563   connect_msg.type = htons (GNUNET_MESSAGE_TYPE_TRANSPORT_CONNECT);
 564   GST_neighbours_send (peer,
 565                        &connect_msg,
 566                        sizeof (connect_msg),
 567                        GNUNET_TIME_UNIT_FOREVER_REL,
 568                        NULL, NULL);
 569 }
 570
 571
 572 /**
 573  * Try to connect to the target peer using the given address
 574  *
 575  * @param cls the 'struct NeighbourMapEntry' of the target
 576  * @param target identity of the target peer
 577  * @param plugin_name name of the plugin
 578  * @param plugin_address binary address
 579  * @param plugin_address_len length of address
 580  * @param bandwidth available bandwidth
 581  * @param ats performance data for the address (as far as known)
 582  * @param ats_count number of performance records in 'ats'
 583  */
 584 static void
 585 try_connect_using_address (void *cls,
 586                            const struct GNUNET_PeerIdentity *target,
 587                            const char *plugin_name,
 588                            const void *plugin_address,
 589                            size_t plugin_address_len,
 590                            struct GNUNET_BANDWIDTH_Value32NBO bandwidth,
 591                            const struct GNUNET_TRANSPORT_ATS_Information *ats,
 592                            uint32_t ats_count)
 593 {
 594   struct NeighbourMapEntry *n = cls;
 595
 596   n->asc = NULL;
 597   GST_neighbours_switch_to_address (target,
 598                                     plugin_name,
 599                                     plugin_address,
 600                                     plugin_address_len,
 601                                     NULL,
 602                                     ats, ats_count);
 603   if (GNUNET_YES == n->is_connected)
 604     return;
 605   n->is_connected = GNUNET_YES;
 606   connect_notify_cb (callback_cls,
 607                      target,
 608                      n->ats,
 609                      n->ats_count);
 610 }
 611
 612
 613 /**
 614  * Try to create a connection to the given target (eventually).
 615  *
 616  * @param target peer to try to connect to
 617  */
 618 void
 619 GST_neighbours_try_connect (const struct GNUNET_PeerIdentity *target)
 620 {
 621   struct NeighbourMapEntry *n;
 622
 623   GNUNET_assert (0 != memcmp (target,
 624                               &GST_my_identity,
 625                               sizeof (struct GNUNET_PeerIdentity)));
 626   n = lookup_neighbour (target);
 627   if ( (NULL != n) &&
 628        (GNUNET_YES == n->is_connected) )
 629     return; /* already connected */
 630   if (n == NULL)
 631     {
 632       n = GNUNET_malloc (sizeof (struct NeighbourMapEntry));
 633       n->id = *target;
 634       GNUNET_BANDWIDTH_tracker_init (&n->in_tracker,
 635                                      GNUNET_CONSTANTS_DEFAULT_BW_IN_OUT,
 636                                      MAX_BANDWIDTH_CARRY_S);
 637       n->timeout_task = GNUNET_SCHEDULER_add_delayed (GNUNET_CONSTANTS_IDLE_CONNECTION_TIMEOUT,
 638                                                       &neighbour_timeout_task, n);
 639       GNUNET_assert (GNUNET_OK ==
 640                      GNUNET_CONTAINER_multihashmap_put (neighbours,
 641                                                         &n->id.hashPubKey,
 642                                                         n,
 643                                                         GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_ONLY));
 644     }
 645   if (n->asc != NULL)
 646     return; /* already trying */
 647   n->asc = GNUNET_ATS_suggest_address (GST_ats,
 648                                        target,
 649                                        &try_connect_using_address,
 650                                        n);
 651 }
 652
 653
 654 /**
 655  * Test if we're connected to the given peer.
 656  *
 657  * @param target peer to test
 658  * @return GNUNET_YES if we are connected, GNUNET_NO if not
 659  */
 660 int
 661 GST_neighbours_test_connected (const struct GNUNET_PeerIdentity *target)
 662 {
 663   struct NeighbourMapEntry *n;
 664
 665   n = lookup_neighbour (target);
 666   if ( (NULL == n) ||
 667        (n->is_connected == GNUNET_YES) )
 668        return GNUNET_NO; /* not connected */
 669   return GNUNET_YES;
 670 }
 671
 672
 673 /**
 674  * Transmit a message to the given target using the active connection.
 675  *
 676  * @param target destination
 677  * @param msg message to send
 678  * @param msg_size number of bytes in msg
 679  * @param timeout when to fail with timeout
 680  * @param cont function to call when done
 681  * @param cont_cls closure for 'cont'
 682  */
 683 void
 684 GST_neighbours_send (const struct GNUNET_PeerIdentity *target,
 685                      const void *msg,
 686                      size_t msg_size,
 687                      struct GNUNET_TIME_Relative timeout,
 688                      GST_NeighbourSendContinuation cont,
 689                      void *cont_cls)
 690 {
 691   struct NeighbourMapEntry *n;
 692   struct MessageQueue *mq;
 693
 694   n = lookup_neighbour (target);
 695   if ( (n == NULL) ||
 696        (GNUNET_YES != n->is_connected) )
 697     {
 698       GNUNET_STATISTICS_update (GST_stats,
 699                                 gettext_noop ("# SET QUOTA messages ignored (no such peer)"),
 700                                 1,
 701                                 GNUNET_NO);
 702       if (NULL != cont)
 703         cont (cont_cls,
 704               GNUNET_SYSERR);
 705       return;
 706     }
 707   GNUNET_assert (msg_size >= sizeof (struct GNUNET_MessageHeader));
 708   GNUNET_STATISTICS_update (GST_stats,
 709                             gettext_noop ("# bytes in message queue for other peers"),
 710                             msg_size,
 711                             GNUNET_NO);
 712   mq = GNUNET_malloc (sizeof (struct MessageQueue) + msg_size);
 713   mq->cont = cont;
 714   mq->cont_cls = cont_cls;
 715   /* FIXME: this memcpy can be up to 7% of our total runtime! */
 716   memcpy (&mq[1], msg, msg_size);
 717   mq->message_buf = (const char*) &mq[1];
 718   mq->message_buf_size = msg_size;
 719   mq->timeout = GNUNET_TIME_relative_to_absolute (timeout);
 720   GNUNET_CONTAINER_DLL_insert_tail (n->messages_head,
 721                                     n->messages_tail,
 722                                     mq);
 723   if ( (GNUNET_SCHEDULER_NO_TASK == n->transmission_task) &&
 724        (NULL == n->is_active) )
 725     n->transmission_task = GNUNET_SCHEDULER_add_now (&transmission_task,
 726                                                      n);
 727 }
 728
 729
 730 /**
 731  * We have received a message from the given sender.  How long should
 732  * we delay before receiving more?  (Also used to keep the peer marked
 733  * as live).
 734  *
 735  * @param sender sender of the message
 736  * @param size size of the message
 737  * @return how long to wait before reading more from this sender
 738  */
 739 struct GNUNET_TIME_Relative
 740 GST_neighbours_calculate_receive_delay (const struct GNUNET_PeerIdentity *sender,
 741                                         ssize_t size)
 742 {
 743   struct NeighbourMapEntry *n;
 744   struct GNUNET_TIME_Relative ret;
 745
 746   n = lookup_neighbour (sender);
 747   if (n == NULL)
 748     return GNUNET_TIME_UNIT_ZERO;
 749   if (GNUNET_YES == GNUNET_BANDWIDTH_tracker_consume (&n->in_tracker,
 750                                                       size))
 751     {
 752       n->quota_violation_count++;
 753 #if DEBUG_TRANSPORT
 754       GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 755                   "Bandwidth quota (%u b/s) violation detected (total of %u).\n",
 756                   n->in_tracker.available_bytes_per_s__,
 757                   n->quota_violation_count);
 758 #endif
 759       /* Discount 32k per violation */
 760       GNUNET_BANDWIDTH_tracker_consume (&n->in_tracker,
 761                                         - 32 * 1024);
 762     }
 763   else
 764     {
 765       if (n->quota_violation_count > 0)
 766         {
 767           /* try to add 32k back */
 768           GNUNET_BANDWIDTH_tracker_consume (&n->in_tracker,
 769                                             32 * 1024);
 770           n->quota_violation_count--;
 771         }
 772     }
 773   GNUNET_SCHEDULER_cancel (n->timeout_task);
 774   n->timeout_task =
 775     GNUNET_SCHEDULER_add_delayed (GNUNET_CONSTANTS_IDLE_CONNECTION_TIMEOUT,
 776                                   &neighbour_timeout_task, n);
 777   if (n->quota_violation_count > QUOTA_VIOLATION_DROP_THRESHOLD)
 778     {
 779       GNUNET_STATISTICS_update (GST_stats,
 780                                 gettext_noop ("# bandwidth quota violations by other peers"),
 781                                 1,
 782                                 GNUNET_NO);
 783       return GNUNET_CONSTANTS_QUOTA_VIOLATION_TIMEOUT;
 784     }
 785   ret = GNUNET_BANDWIDTH_tracker_get_delay (&n->in_tracker, 0);
 786   if (ret.rel_value > 0)
 787     {
 788 #if DEBUG_TRANSPORT
 789       GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 790                   "Throttling read (%llu bytes excess at %u b/s), waiting %llu ms before reading more.\n",
 791                   (unsigned long long) n->in_tracker.consumption_since_last_update__,
 792                   (unsigned int) n->in_tracker.available_bytes_per_s__,
 793                   (unsigned long long) ret.rel_value);
 794 #endif
 795       GNUNET_STATISTICS_update (GST_stats,
 796                                 gettext_noop ("# ms throttling suggested"),
 797                                 (int64_t) ret.rel_value,
 798                                 GNUNET_NO);
 799     }
 800   return ret;
 801 }
 802
 803
 804 /**
 805  * Change the incoming quota for the given peer.
 806  *
 807  * @param neighbour identity of peer to change qutoa for
 808  * @param quota new quota
 809  */
 810 void
 811 GST_neighbours_set_incoming_quota (const struct GNUNET_PeerIdentity *neighbour,
 812                                    struct GNUNET_BANDWIDTH_Value32NBO quota)
 813 {
 814   struct NeighbourMapEntry *n;
 815
 816   n = lookup_neighbour (neighbour);
 817   if (n == NULL)
 818     {
 819       GNUNET_STATISTICS_update (GST_stats,
 820                                 gettext_noop ("# SET QUOTA messages ignored (no such peer)"),
 821                                 1,
 822                                 GNUNET_NO);
 823       return;
 824     }
 825   GNUNET_BANDWIDTH_tracker_update_quota (&n->in_tracker,
 826                                          quota);
 827   if (0 != ntohl (quota.value__))
 828     return;
 829 #if DEBUG_TRANSPORT
 830   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 831               "Disconnecting peer `%4s' due to `%s'\n",
 832               GNUNET_i2s(&n->id),
 833               "SET_QUOTA");
 834 #endif
 835   GNUNET_STATISTICS_update (GST_stats,
 836                             gettext_noop ("# disconnects due to quota of 0"),
 837                             1,
 838                             GNUNET_NO);
 839   disconnect_neighbour (n);
 840 }
 841
 842
 843 /**
 844  * Closure for the neighbours_iterate function.
 845  */
 846 struct IteratorContext
 847 {
 848   /**
 849    * Function to call on each connected neighbour.
 850    */
 851   GST_NeighbourIterator cb;
 852
 853   /**
 854    * Closure for 'cb'.
 855    */
 856   void *cb_cls;
 857 };
 858
 859
 860 /**
 861  * Call the callback from the closure for each connected neighbour.
 862  *
 863  * @param cls the 'struct IteratorContext'
 864  * @param key the hash of the public key of the neighbour
 865  * @param value the 'struct NeighbourMapEntry'
 866  * @return GNUNET_OK (continue to iterate)
 867  */
 868 static int
 869 neighbours_iterate (void *cls,
 870                     const GNUNET_HashCode *key,
 871                     void *value)
 872 {
 873   struct IteratorContext *ic = cls;
 874   struct NeighbourMapEntry *n = value;
 875
 876   if (GNUNET_YES != n->is_connected)
 877     return GNUNET_OK;
 878   GNUNET_assert (n->ats_count > 0);
 879   ic->cb (ic->cb_cls,
 880           &n->id,
 881           n->ats,
 882           n->ats_count - 1);
 883   return GNUNET_OK;
 884 }
 885
 886
 887 /**
 888  * Iterate over all connected neighbours.
 889  *
 890  * @param cb function to call
 891  * @param cb_cls closure for cb
 892  */
 893 void
 894 GST_neighbours_iterate (GST_NeighbourIterator cb,
 895                         void *cb_cls)
 896 {
 897   struct IteratorContext ic;
 898
 899   ic.cb = cb;
 900   ic.cb_cls = cb_cls;
 901   GNUNET_CONTAINER_multihashmap_iterate (neighbours,
 902                                          &neighbours_iterate,
 903                                          &ic);
 904 }
 905
 906
 907 /**
 908  * If we have an active connection to the given target, it must be shutdown.
 909  *
 910  * @param target peer to disconnect from
 911  */
 912 void
 913 GST_neighbours_force_disconnect (const struct GNUNET_PeerIdentity *target)
 914 {
 915   struct NeighbourMapEntry *n;
 916   struct GNUNET_TRANSPORT_PluginFunctions *papi;
 917   struct GNUNET_MessageHeader disconnect_msg;
 918
 919   n = lookup_neighbour (target);
 920   disconnect_msg.size = htons (sizeof (struct GNUNET_MessageHeader));
 921   disconnect_msg.type = htons (GNUNET_MESSAGE_TYPE_TRANSPORT_CONNECT);
 922   papi = GST_plugins_find (n->plugin_name);
 923   if (papi != NULL)
 924     papi->send (papi->cls,
 925                 target,
 926                 (const void*) &disconnect_msg,
 927                 sizeof (struct GNUNET_MessageHeader),
 928                 UINT32_MAX /* priority */,
 929                 GNUNET_TIME_UNIT_FOREVER_REL,
 930                 n->session,
 931                 n->addr,
 932                 n->addrlen,
 933                 GNUNET_YES,
 934                 NULL, NULL);
 935   disconnect_neighbour (n);
 936 }
 937
 938
 939 /* end of file gnunet-service-transport_neighbours.c */