src/transport/gnunet-service-transport_neighbours.c

   1 /*
   2      This file is part of GNUnet.
   3      Copyright (C) 2010-2015 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_ats.h"
  29 #include "gnunet-service-transport_blacklist.h"
  30 #include "gnunet-service-transport_clients.h"
  31 #include "gnunet-service-transport_neighbours.h"
  32 #include "gnunet-service-transport_manipulation.h"
  33 #include "gnunet-service-transport_plugins.h"
  34 #include "gnunet-service-transport_validation.h"
  35 #include "gnunet-service-transport.h"
  36 #include "gnunet_peerinfo_service.h"
  37 #include "gnunet_constants.h"
  38 #include "transport.h"
  39
  40
  41 /**
  42  * Size of the neighbour hash map.
  43  */
  44 #define NEIGHBOUR_TABLE_SIZE 256
  45
  46 /**
  47  * Time we give plugin to transmit DISCONNECT message before the
  48  * neighbour entry self-destructs.
  49  */
  50 #define DISCONNECT_SENT_TIMEOUT GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_MILLISECONDS, 500)
  51
  52 /**
  53  * How often must a peer violate bandwidth quotas before we start
  54  * to simply drop its messages?
  55  */
  56 #define QUOTA_VIOLATION_DROP_THRESHOLD 10
  57
  58 /**
  59  * How long are we willing to wait for a response from ATS before timing out?
  60  */
  61 #define ATS_RESPONSE_TIMEOUT GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_SECONDS, 5)
  62
  63 /**
  64  * How long are we willing to wait for an ACK from the other peer before
  65  * giving up on our connect operation?
  66  */
  67 #define SETUP_CONNECTION_TIMEOUT GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_SECONDS, 15)
  68
  69 /**
  70  * How long are we willing to wait for a successful reconnect if
  71  * an existing connection went down?  Much shorter than the
  72  * usual SETUP_CONNECTION_TIMEOUT as we do not inform the
  73  * higher layers about the disconnect during this period.
  74  */
  75 #define FAST_RECONNECT_TIMEOUT GNUNET_TIME_UNIT_SECONDS
  76
  77 /**
  78  * Interval to send utilization data
  79  */
  80 #define UTIL_TRANSMISSION_INTERVAL GNUNET_TIME_UNIT_SECONDS
  81
  82 /**
  83  * State describing which kind a reply this neighbour should send
  84  */
  85 enum GST_ACK_State
  86 {
  87   /**
  88    * We did not receive a SYN message for this neighbour
  89    */
  90   ACK_UNDEFINED = 0,
  91
  92   /**
  93    * The neighbour received a SYN message and has to send a SYN_ACK
  94    * as reply
  95    */
  96   ACK_SEND_SYN_ACK = 1,
  97
  98   /**
  99    * The neighbour sent a SYN_ACK message and has to send a ACK
 100    * as reply
 101    */
 102   ACK_SEND_ACK = 2
 103 };
 104
 105
 106 GNUNET_NETWORK_STRUCT_BEGIN
 107
 108 /**
 109  * Message a peer sends to another to indicate that it intends to
 110  * setup a connection/session for data exchange.  A 'SESSION_SYN'
 111  * should be answered with a 'SESSION_SYN_ACK' with the same body
 112  * to confirm.  A 'SESSION_SYN_ACK' should then be followed with
 113  * a 'ACK'.  Once the 'ACK' is received, both peers
 114  * should be connected.
 115  */
 116 struct TransportSynMessage
 117 {
 118   /**
 119    * Header of type #GNUNET_MESSAGE_TYPE_TRANSPORT_SESSION_SYN
 120    * or #GNUNET_MESSAGE_TYPE_TRANSPORT_SESSION_SYN_ACK
 121    */
 122   struct GNUNET_MessageHeader header;
 123
 124   /**
 125    * Always zero.
 126    */
 127   uint32_t reserved GNUNET_PACKED;
 128
 129   /**
 130    * Absolute time at the sender.  Only the most recent connect
 131    * message implies which session is preferred by the sender.
 132    */
 133   struct GNUNET_TIME_AbsoluteNBO timestamp;
 134
 135 };
 136
 137
 138 /**
 139  * Message a peer sends to another when connected to indicate that a
 140  * session is in use and the peer is still alive or to respond to a keep alive.
 141  * A peer sends a message with type #GNUNET_MESSAGE_TYPE_TRANSPORT_SESSION_KEEPALIVE
 142  * to request a message with #GNUNET_MESSAGE_TYPE_TRANSPORT_SESSION_KEEPALIVE_RESPONSE.
 143  * When the keep alive response with type is received, transport service
 144  * will call the respective plugin to update the session timeout
 145  */
 146 struct SessionKeepAliveMessage
 147 {
 148   /**
 149    * Header of type #GNUNET_MESSAGE_TYPE_TRANSPORT_SESSION_KEEPALIVE or
 150    * #GNUNET_MESSAGE_TYPE_TRANSPORT_SESSION_KEEPALIVE_RESPONSE.
 151    */
 152   struct GNUNET_MessageHeader header;
 153
 154   /**
 155    * A nonce to identify the session the keep alive is used for
 156    */
 157   uint32_t nonce GNUNET_PACKED;
 158 };
 159
 160 /**
 161  * Message we send to the other peer to notify him that we intentionally
 162  * are disconnecting (to reduce timeouts).  This is just a friendly
 163  * notification, peers must not rely on always receiving disconnect
 164  * messages.
 165  */
 166 struct SessionDisconnectMessage
 167 {
 168   /**
 169    * Header of type #GNUNET_MESSAGE_TYPE_TRANSPORT_SESSION_DISCONNECT
 170    */
 171   struct GNUNET_MessageHeader header;
 172
 173   /**
 174    * Always zero.
 175    */
 176   uint32_t reserved GNUNET_PACKED;
 177
 178   /**
 179    * Purpose of the signature.  Extends over the timestamp.
 180    * Purpose should be #GNUNET_SIGNATURE_PURPOSE_TRANSPORT_DISCONNECT.
 181    */
 182   struct GNUNET_CRYPTO_EccSignaturePurpose purpose;
 183
 184   /**
 185    * Absolute time at the sender.  Only the most recent connect
 186    * message implies which session is preferred by the sender.
 187    */
 188   struct GNUNET_TIME_AbsoluteNBO timestamp;
 189
 190   /**
 191    * Public key of the sender.
 192    */
 193   struct GNUNET_CRYPTO_EddsaPublicKey public_key;
 194
 195   /**
 196    * Signature of the peer that sends us the disconnect.  Only
 197    * valid if the timestamp is AFTER the timestamp from the
 198    * corresponding 'SYN' message.
 199    */
 200   struct GNUNET_CRYPTO_EddsaSignature signature;
 201
 202 };
 203
 204 GNUNET_NETWORK_STRUCT_END
 205
 206
 207 /**
 208  * For each neighbour we keep a list of messages
 209  * that we still want to transmit to the neighbour.
 210  */
 211 struct MessageQueue
 212 {
 213
 214   /**
 215    * This is a doubly linked list.
 216    */
 217   struct MessageQueue *next;
 218
 219   /**
 220    * This is a doubly linked list.
 221    */
 222   struct MessageQueue *prev;
 223
 224   /**
 225    * Function to call once we're done.
 226    */
 227   GST_NeighbourSendContinuation cont;
 228
 229   /**
 230    * Closure for @e cont
 231    */
 232   void *cont_cls;
 233
 234   /**
 235    * The message(s) we want to transmit, GNUNET_MessageHeader(s)
 236    * stuck together in memory.  Allocated at the end of this struct.
 237    */
 238   const char *message_buf;
 239
 240   /**
 241    * Size of the message buf
 242    */
 243   size_t message_buf_size;
 244
 245   /**
 246    * At what time should we fail?
 247    */
 248   struct GNUNET_TIME_Absolute timeout;
 249
 250 };
 251
 252
 253 /**
 254  * A possible address we could use to communicate with a neighbour.
 255  */
 256 struct NeighbourAddress
 257 {
 258
 259   /**
 260    * Active session for this address.
 261    */
 262   struct Session *session;
 263
 264   /**
 265    * Network-level address information.
 266    */
 267   struct GNUNET_HELLO_Address *address;
 268
 269   /**
 270    * Timestamp of the 'SESSION_CONNECT' message we sent to the other
 271    * peer for this address.  Use to check that the ACK is in response
 272    * to our most recent 'SYN'.
 273    */
 274   struct GNUNET_TIME_Absolute connect_timestamp;
 275
 276   /**
 277    * Inbound bandwidth from ATS for this address.
 278    */
 279   struct GNUNET_BANDWIDTH_Value32NBO bandwidth_in;
 280
 281   /**
 282    * Outbound bandwidth from ATS for this address.
 283    */
 284   struct GNUNET_BANDWIDTH_Value32NBO bandwidth_out;
 285
 286   /**
 287    * Did we tell ATS that this is our 'active' address?
 288    */
 289   int ats_active;
 290
 291   /**
 292    * The current nonce sent in the last keep alive messages
 293    */
 294   uint32_t keep_alive_nonce;
 295 };
 296
 297
 298 /**
 299  * Entry in neighbours.
 300  */
 301 struct NeighbourMapEntry
 302 {
 303
 304   /**
 305    * Head of list of messages we would like to send to this peer;
 306    * must contain at most one message per client.
 307    */
 308   struct MessageQueue *messages_head;
 309
 310   /**
 311    * Tail of list of messages we would like to send to this peer; must
 312    * contain at most one message per client.
 313    */
 314   struct MessageQueue *messages_tail;
 315
 316   /**
 317    * Are we currently trying to send a message? If so, which one?
 318    */
 319   struct MessageQueue *is_active;
 320
 321   /**
 322    * Primary address we currently use to communicate with the neighbour.
 323    */
 324   struct NeighbourAddress primary_address;
 325
 326   /**
 327    * Alternative address currently under consideration for communicating
 328    * with the neighbour.
 329    */
 330   struct NeighbourAddress alternative_address;
 331
 332   /**
 333    * Identity of this neighbour.
 334    */
 335   struct GNUNET_PeerIdentity id;
 336
 337   /**
 338    * Main task that drives this peer (timeouts, keepalives, etc.).
 339    * Always runs the 'master_task'.
 340    */
 341   struct GNUNET_SCHEDULER_Task *task;
 342
 343   /**
 344    * Task to disconnect neighbour after we received a DISCONNECT message
 345    */
 346   struct GNUNET_SCHEDULER_Task *delayed_disconnect_task;
 347
 348   /**
 349    * At what time should we sent the next keep-alive message?
 350    */
 351   struct GNUNET_TIME_Absolute keep_alive_time;
 352
 353   /**
 354    * At what time did we sent the last keep-alive message?  Used
 355    * to calculate round-trip time ("latency").
 356    */
 357   struct GNUNET_TIME_Absolute last_keep_alive_time;
 358
 359   /**
 360    * Timestamp we should include in our next SYN_ACK message.
 361    * (only valid if 'send_connect_ack' is #GNUNET_YES).  Used to build
 362    * our SYN_ACK message.
 363    */
 364   struct GNUNET_TIME_Absolute connect_ack_timestamp;
 365
 366   /**
 367    * ATS address suggest handle
 368    */
 369   struct GNUNET_ATS_ConnectivitySuggestHandle *suggest_handle;
 370
 371   /**
 372    * Time where we should cut the connection (timeout) if we don't
 373    * make progress in the state machine (or get a KEEPALIVE_RESPONSE
 374    * if we are in #S_CONNECTED).
 375    */
 376   struct GNUNET_TIME_Absolute timeout;
 377
 378   /**
 379    * Tracker for inbound bandwidth.
 380    */
 381   struct GNUNET_BANDWIDTH_Tracker in_tracker;
 382
 383   /**
 384    * How often has the other peer (recently) violated the inbound
 385    * traffic limit?  Incremented by 10 per violation, decremented by 1
 386    * per non-violation (for each time interval).
 387    */
 388   unsigned int quota_violation_count;
 389
 390   /**
 391    * The current state of the peer.
 392    */
 393   enum GNUNET_TRANSPORT_PeerState state;
 394
 395   /**
 396    * Did we sent an KEEP_ALIVE message and are we expecting a response?
 397    */
 398   int expect_latency_response;
 399
 400   /**
 401    * When a peer wants to connect we have to reply to the 1st SYN message
 402    * with a SYN_ACK message. But sometime we cannot send this message
 403    * immediately since we do not have an address and then we have to remember
 404    * to send this message as soon as we have an address.
 405    *
 406    * Flag to set if we still need to send a SYN_ACK message to the other peer
 407    * (once we have an address to use and the peer has been allowed by our
 408    * blacklist).  Initially set to #ACK_UNDEFINED. Set to #ACK_SEND_SYN_ACK
 409    * if we need to send a SYN_ACK.  Set to #ACK_SEND_ACK if we did
 410    * send a SYN_ACK and should go to #S_CONNECTED upon receiving a
 411    * 'ACK' (regardless of what our own state machine might say).
 412    */
 413   enum GST_ACK_State ack_state;
 414
 415   /**
 416    * Tracking utilization of outbound bandwidth
 417    */
 418   uint32_t util_total_bytes_sent;
 419
 420   /**
 421    * Tracking utilization of inbound bandwidth
 422    */
 423   uint32_t util_total_bytes_recv;
 424
 425   /**
 426    * Date of last utilization transmission
 427    */
 428   struct GNUNET_TIME_Absolute last_util_transmission;
 429 };
 430
 431
 432 /**
 433  * Context for blacklist checks and the #try_connect_bl_check_cont()
 434  * function.  Stores information about ongoing blacklist checks.
 435  */
 436 struct BlackListCheckContext
 437 {
 438
 439   /**
 440    * We keep blacklist checks in a DLL.
 441    */
 442   struct BlackListCheckContext *next;
 443
 444   /**
 445    * We keep blacklist checks in a DLL.
 446    */
 447   struct BlackListCheckContext *prev;
 448
 449   /**
 450    * Address that is being checked.
 451    */
 452   struct NeighbourAddress na;
 453
 454   /**
 455    * Handle to the ongoing blacklist check.
 456    */
 457   struct GST_BlacklistCheck *bc;
 458 };
 459
 460
 461 /**
 462  * Hash map from peer identities to the respective `struct NeighbourMapEntry`.
 463  */
 464 static struct GNUNET_CONTAINER_MultiPeerMap *neighbours;
 465
 466 /**
 467  * We keep blacklist checks in a DLL so that we can find
 468  * the 'sessions' in their 'struct NeighbourAddress' if
 469  * a session goes down.
 470  */
 471 static struct BlackListCheckContext *bc_head;
 472
 473 /**
 474  * We keep blacklist checks in a DLL.
 475  */
 476 static struct BlackListCheckContext *bc_tail;
 477
 478 /**
 479  * List of pending blacklist checks: head
 480  */
 481 static struct BlacklistCheckSwitchContext *pending_bc_head;
 482
 483 /**
 484  * List of pending blacklist checks: tail
 485  */
 486 static struct BlacklistCheckSwitchContext *pending_bc_tail;
 487
 488 /**
 489  * counter for connected neighbours
 490  */
 491 static unsigned int neighbours_connected;
 492
 493 /**
 494  * Number of bytes we have currently queued for transmission.
 495  */
 496 static unsigned long long bytes_in_send_queue;
 497
 498 /**
 499  * Task transmitting utilization data
 500  */
 501 static struct GNUNET_SCHEDULER_Task *util_transmission_tk;
 502
 503
 504 /**
 505  * Convert the given ACK state to a string.
 506  *
 507  * @param s state
 508  * @return corresponding human-readable string
 509  */
 510 static char *
 511 print_ack_state (enum GST_ACK_State s)
 512 {
 513   switch (s) {
 514     case ACK_UNDEFINED:
 515       return "UNDEFINED";
 516     case ACK_SEND_SYN_ACK:
 517       return "SEND_SYN_ACK";
 518     case ACK_SEND_ACK:
 519       return "SEND_ACK";
 520     default:
 521       GNUNET_break (0);
 522       return "N/A";
 523   }
 524 }
 525
 526
 527 /**
 528  * Notify our clients that another peer connected to us.
 529  *
 530  * @param peer the peer that connected
 531  * @param bandwidth_in inbound bandwidth in NBO
 532  * @param bandwidth_out outbound bandwidth in NBO
 533  */
 534 static void
 535 neighbours_connect_notification (const struct GNUNET_PeerIdentity *peer,
 536                                  struct GNUNET_BANDWIDTH_Value32NBO bandwidth_in,
 537                                  struct GNUNET_BANDWIDTH_Value32NBO bandwidth_out)
 538 {
 539   size_t len = sizeof(struct ConnectInfoMessage);
 540   char buf[len] GNUNET_ALIGN;
 541   struct ConnectInfoMessage *connect_msg = (struct ConnectInfoMessage *) buf;
 542
 543   GNUNET_log (GNUNET_ERROR_TYPE_INFO,
 544               "We are now connected to peer `%s'\n",
 545               GNUNET_i2s (peer));
 546   connect_msg->header.size = htons (sizeof(buf));
 547   connect_msg->header.type = htons (GNUNET_MESSAGE_TYPE_TRANSPORT_CONNECT);
 548   connect_msg->id = *peer;
 549   connect_msg->quota_in = bandwidth_in;
 550   connect_msg->quota_out = bandwidth_out;
 551   GST_clients_broadcast (&connect_msg->header, GNUNET_NO);
 552 }
 553
 554
 555 /**
 556  * Notify our clients (and manipulation) that a peer disconnected from
 557  * us.
 558  *
 559  * @param peer the peer that disconnected
 560  */
 561 static void
 562 neighbours_disconnect_notification (const struct GNUNET_PeerIdentity *peer)
 563 {
 564   struct DisconnectInfoMessage disconnect_msg;
 565
 566   GNUNET_log (GNUNET_ERROR_TYPE_INFO,
 567               "Peer `%s' disconnected\n",
 568               GNUNET_i2s (peer));
 569   GST_manipulation_peer_disconnect (peer);
 570   disconnect_msg.header.size = htons (sizeof(struct DisconnectInfoMessage));
 571   disconnect_msg.header.type = htons (GNUNET_MESSAGE_TYPE_TRANSPORT_DISCONNECT);
 572   disconnect_msg.reserved = htonl (0);
 573   disconnect_msg.peer = *peer;
 574   GST_clients_broadcast (&disconnect_msg.header,
 575                          GNUNET_NO);
 576 }
 577
 578
 579 /**
 580  * Notify transport clients that a neighbour peer changed its active
 581  * address.
 582  *
 583  * @param peer identity of the peer
 584  * @param address address possibly NULL if peer is not connected
 585  * @param state current state this peer is in
 586  * @param state_timeout timeout for the current state of the peer
 587  * @param bandwidth_in bandwidth assigned inbound, 0 on disconnect
 588  * @param bandwidth_out bandwidth assigned outbound, 0 on disconnect
 589  */
 590 static void
 591 neighbours_changed_notification (const struct GNUNET_PeerIdentity *peer,
 592                                  const struct GNUNET_HELLO_Address *address,
 593                                  enum GNUNET_TRANSPORT_PeerState state,
 594                                  struct GNUNET_TIME_Absolute state_timeout,
 595                                  struct GNUNET_BANDWIDTH_Value32NBO bandwidth_in,
 596                                  struct GNUNET_BANDWIDTH_Value32NBO bandwidth_out)
 597 {
 598   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 599               "Notifying about change for peer `%s' with address `%s' in state `%s' timing out at %s\n",
 600               GNUNET_i2s (peer),
 601               GST_plugins_a2s (address),
 602               GNUNET_TRANSPORT_ps2s (state),
 603               GNUNET_STRINGS_absolute_time_to_string (state_timeout));
 604   /* FIXME: include bandwidth in notification! */
 605   GST_clients_broadcast_peer_notification (peer,
 606                                            address,
 607                                            state,
 608                                            state_timeout);
 609 }
 610
 611
 612 /**
 613  * Lookup a neighbour entry in the neighbours hash map.
 614  *
 615  * @param pid identity of the peer to look up
 616  * @return the entry, NULL if there is no existing record
 617  */
 618 static struct NeighbourMapEntry *
 619 lookup_neighbour (const struct GNUNET_PeerIdentity *pid)
 620 {
 621   if (NULL == neighbours)
 622     return NULL;
 623   return GNUNET_CONTAINER_multipeermap_get (neighbours, pid);
 624 }
 625
 626
 627 /**
 628  * Test if we're connected to the given peer.
 629  *
 630  * @param n neighbour entry of peer to test
 631  * @return #GNUNET_YES if we are connected, #GNUNET_NO if not
 632  */
 633 static int
 634 test_connected (struct NeighbourMapEntry *n)
 635 {
 636   if (NULL == n)
 637     return GNUNET_NO;
 638   return GNUNET_TRANSPORT_is_connected (n->state);
 639 }
 640
 641
 642 /**
 643  * Send information about a new outbound quota to our clients.
 644  *
 645  * @param target affected peer
 646  * @param quota new quota
 647  */
 648 static void
 649 send_outbound_quota (const struct GNUNET_PeerIdentity *target,
 650                      struct GNUNET_BANDWIDTH_Value32NBO quota)
 651 {
 652   struct QuotaSetMessage q_msg;
 653
 654   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 655               "Sending outbound quota of %u Bps for peer `%s' to all clients\n",
 656               ntohl (quota.value__),
 657               GNUNET_i2s (target));
 658   q_msg.header.size = htons (sizeof (struct QuotaSetMessage));
 659   q_msg.header.type = htons (GNUNET_MESSAGE_TYPE_TRANSPORT_SET_QUOTA);
 660   q_msg.quota = quota;
 661   q_msg.peer = (*target);
 662   GST_clients_broadcast (&q_msg.header, GNUNET_NO);
 663 }
 664
 665
 666 /**
 667  * We don't need a given neighbour address any more.
 668  * Release its resources and give appropriate notifications
 669  * to ATS and other subsystems.
 670  *
 671  * @param na address we are done with; @a na itself must NOT be 'free'd, only the contents!
 672  */
 673 static void
 674 free_address (struct NeighbourAddress *na)
 675 {
 676   if (GNUNET_YES == na->ats_active)
 677     GST_validation_set_address_use (na->address,
 678                                     GNUNET_NO);
 679   if (NULL != na->address)
 680   {
 681     GST_ats_block_address (na->address,
 682                            na->session);
 683     GNUNET_HELLO_address_free (na->address);
 684     na->address = NULL;
 685   }
 686   na->bandwidth_in = GNUNET_BANDWIDTH_value_init (0);
 687   na->bandwidth_out = GNUNET_BANDWIDTH_value_init (0);
 688   na->ats_active = GNUNET_NO;
 689   na->keep_alive_nonce = 0;
 690   na->session = NULL;
 691 }
 692
 693
 694 /**
 695  * Master task run for every neighbour.  Performs all of the time-related
 696  * activities (keep alive, send next message, disconnect if idle, finish
 697  * clean up after disconnect).
 698  *
 699  * @param cls the `struct NeighbourMapEntry` for which we are running
 700  * @param tc scheduler context (unused)
 701  */
 702 static void
 703 master_task (void *cls,
 704              const struct GNUNET_SCHEDULER_TaskContext *tc);
 705
 706
 707 /**
 708  * Set net state and state timeout for this neighbour and notify monitoring
 709  *
 710  * @param n the respective neighbour
 711  * @param s the new state
 712  * @param timeout the new timeout
 713  */
 714 static void
 715 set_state_and_timeout (struct NeighbourMapEntry *n,
 716                        enum GNUNET_TRANSPORT_PeerState s,
 717                        struct GNUNET_TIME_Absolute timeout)
 718 {
 719   if (GNUNET_TRANSPORT_is_connected (s) &&
 720       ! GNUNET_TRANSPORT_is_connected (n->state) )
 721   {
 722     neighbours_connect_notification (&n->id,
 723                                      n->primary_address.bandwidth_in,
 724                                      n->primary_address.bandwidth_out);
 725     GNUNET_STATISTICS_set (GST_stats,
 726                            gettext_noop ("# peers connected"),
 727                            ++neighbours_connected,
 728                            GNUNET_NO);
 729   }
 730   if (! GNUNET_TRANSPORT_is_connected (s) &&
 731         GNUNET_TRANSPORT_is_connected (n->state) )
 732   {
 733     GNUNET_STATISTICS_set (GST_stats,
 734                            gettext_noop ("# peers connected"),
 735                            --neighbours_connected,
 736                            GNUNET_NO);
 737     neighbours_disconnect_notification (&n->id);
 738   }
 739   n->state = s;
 740   if ( (timeout.abs_value_us < n->timeout.abs_value_us) &&
 741        (NULL != n->task ) )
 742   {
 743     /* new timeout is earlier, reschedule master task */
 744     GNUNET_SCHEDULER_cancel (n->task);
 745     n->task = GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_absolute_get_remaining (timeout),
 746                                             &master_task,
 747                                             n);
 748   }
 749   n->timeout = timeout;
 750   GNUNET_log (GNUNET_ERROR_TYPE_INFO,
 751               "Neighbour `%s' changed state to %s with timeout %s\n",
 752               GNUNET_i2s (&n->id),
 753               GNUNET_TRANSPORT_ps2s(s),
 754               GNUNET_STRINGS_absolute_time_to_string (timeout));
 755   neighbours_changed_notification (&n->id,
 756                                    n->primary_address.address,
 757                                    n->state,
 758                                    n->timeout,
 759                                    n->primary_address.bandwidth_in,
 760                                    n->primary_address.bandwidth_out);
 761 }
 762
 763
 764 /**
 765  * Initialize the alternative address of a neighbour
 766  *
 767  * @param n the neighbour
 768  * @param address address of the other peer, NULL if other peer
 769  *                       connected to us
 770  * @param session session to use (or NULL, in which case an
 771  *        address must be setup)
 772  * @param bandwidth_in inbound quota to be used when connection is up
 773  * @param bandwidth_out outbound quota to be used when connection is up
 774  */
 775 static void
 776 set_alternative_address (struct NeighbourMapEntry *n,
 777                          const struct GNUNET_HELLO_Address *address,
 778                          struct Session *session,
 779                          struct GNUNET_BANDWIDTH_Value32NBO bandwidth_in,
 780                          struct GNUNET_BANDWIDTH_Value32NBO bandwidth_out)
 781 {
 782   struct GNUNET_TRANSPORT_PluginFunctions *papi;
 783
 784   if (NULL == (papi = GST_plugins_find (address->transport_name)))
 785   {
 786     GNUNET_break (0);
 787     return;
 788   }
 789   if (session == n->alternative_address.session)
 790   {
 791     n->alternative_address.bandwidth_in = bandwidth_in;
 792     n->alternative_address.bandwidth_out = bandwidth_out;
 793     return;
 794   }
 795   if (NULL != n->alternative_address.address)
 796   {
 797     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 798                 "Replacing existing alternative address with another one\n");
 799     free_address (&n->alternative_address);
 800   }
 801   if (NULL == session)
 802     session = papi->get_session (papi->cls,
 803                                  address);
 804   if (NULL == session)
 805   {
 806     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 807                 "Failed to obtain new session for peer `%s' and  address '%s'\n",
 808                 GNUNET_i2s (&address->peer),
 809                 GST_plugins_a2s (address));
 810     GNUNET_STATISTICS_update (GST_stats,
 811                               gettext_noop ("# session creation failed"),
 812                               1,
 813                               GNUNET_NO);
 814     return;
 815   }
 816   GST_ats_new_session (address,
 817                        session);
 818   GNUNET_log (GNUNET_ERROR_TYPE_INFO,
 819               "Neighbour `%s' configured alternative address %s\n",
 820               GNUNET_i2s (&n->id),
 821               GST_plugins_a2s(address));
 822
 823   n->alternative_address.address = GNUNET_HELLO_address_copy (address);
 824   n->alternative_address.bandwidth_in = bandwidth_in;
 825   n->alternative_address.bandwidth_out = bandwidth_out;
 826   n->alternative_address.session = session;
 827   n->alternative_address.ats_active = GNUNET_NO;
 828   n->alternative_address.keep_alive_nonce = 0;
 829 }
 830
 831
 832 /**
 833  * Initialize the primary address of a neighbour
 834  *
 835  * @param n the neighbour
 836  * @param address address of the other peer, NULL if other peer
 837  *                       connected to us
 838  * @param session session to use (or NULL, in which case an
 839  *        address must be setup)
 840  * @param bandwidth_in inbound quota to be used when connection is up
 841  * @param bandwidth_out outbound quota to be used when connection is up
 842  */
 843 static void
 844 set_primary_address (struct NeighbourMapEntry *n,
 845                      const struct GNUNET_HELLO_Address *address,
 846                      struct Session *session,
 847                      struct GNUNET_BANDWIDTH_Value32NBO bandwidth_in,
 848                      struct GNUNET_BANDWIDTH_Value32NBO bandwidth_out)
 849 {
 850   if (session == n->primary_address.session)
 851   {
 852     GST_validation_set_address_use (n->primary_address.address,
 853                                     GNUNET_YES);
 854     if (n->primary_address.bandwidth_in.value__ != bandwidth_in.value__)
 855     {
 856       n->primary_address.bandwidth_in = bandwidth_in;
 857       GST_neighbours_set_incoming_quota (&address->peer,
 858                                          bandwidth_in);
 859     }
 860     if (n->primary_address.bandwidth_out.value__ != bandwidth_out.value__)
 861     {
 862       n->primary_address.bandwidth_out = bandwidth_out;
 863       send_outbound_quota (&address->peer,
 864                            bandwidth_out);
 865     }
 866     return;
 867   }
 868   if ( (NULL != n->primary_address.address) &&
 869        (0 == GNUNET_HELLO_address_cmp (address,
 870                                        n->primary_address.address)) )
 871   {
 872     GNUNET_break (0);
 873     return;
 874   }
 875   if (NULL == session)
 876   {
 877     GNUNET_break (0);
 878     GST_ats_block_address (address,
 879                            session);
 880     return;
 881   }
 882   if (NULL != n->primary_address.address)
 883   {
 884     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 885                 "Replacing existing primary address with another one\n");
 886     free_address (&n->primary_address);
 887   }
 888   n->primary_address.address = GNUNET_HELLO_address_copy (address);
 889   n->primary_address.bandwidth_in = bandwidth_in;
 890   n->primary_address.bandwidth_out = bandwidth_out;
 891   n->primary_address.session = session;
 892   n->primary_address.keep_alive_nonce = 0;
 893   /* subsystems about address use */
 894   GST_validation_set_address_use (n->primary_address.address,
 895                                   GNUNET_YES);
 896   GST_neighbours_set_incoming_quota (&address->peer,
 897                                      bandwidth_in);
 898   send_outbound_quota (&address->peer,
 899                        bandwidth_out);
 900   GNUNET_log (GNUNET_ERROR_TYPE_INFO,
 901               "Neighbour `%s' switched to address `%s'\n",
 902               GNUNET_i2s (&n->id),
 903               GST_plugins_a2s(address));
 904
 905   neighbours_changed_notification (&n->id,
 906                                    n->primary_address.address,
 907                                    n->state,
 908                                    n->timeout,
 909                                    n->primary_address.bandwidth_in,
 910                                    n->primary_address.bandwidth_out);
 911 }
 912
 913
 914 /**
 915  * Clear the primary address of a neighbour since this address is not
 916  * valid anymore and notify monitoring about it
 917  *
 918  * @param n the neighbour
 919  */
 920 static void
 921 unset_primary_address (struct NeighbourMapEntry *n)
 922 {
 923   /* Notify monitoring about change */
 924   if (NULL == n->primary_address.address)
 925     return;
 926   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 927               "Disabling primary address\n");
 928   neighbours_changed_notification (&n->id,
 929                                    n->primary_address.address,
 930                                    n->state,
 931                                    n->timeout,
 932                                    GNUNET_BANDWIDTH_value_init (0),
 933                                    GNUNET_BANDWIDTH_value_init (0));
 934   free_address (&n->primary_address);
 935 }
 936
 937
 938 /**
 939  * Free a neighbour map entry.
 940  *
 941  * @param n entry to free
 942  */
 943 static void
 944 free_neighbour (struct NeighbourMapEntry *n)
 945 {
 946   struct MessageQueue *mq;
 947
 948   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 949               "Freeing neighbour state of peer `%s'\n",
 950               GNUNET_i2s (&n->id));
 951   n->is_active = NULL; /* always free'd by its own continuation! */
 952
 953   /* fail messages currently in the queue */
 954   while (NULL != (mq = n->messages_head))
 955   {
 956     GNUNET_CONTAINER_DLL_remove (n->messages_head,
 957                                  n->messages_tail,
 958                                  mq);
 959     if (NULL != mq->cont)
 960       mq->cont (mq->cont_cls,
 961                 GNUNET_SYSERR,
 962                 mq->message_buf_size,
 963                 0);
 964     GNUNET_free (mq);
 965   }
 966   /* Mark peer as disconnected */
 967   set_state_and_timeout (n,
 968                          GNUNET_TRANSPORT_PS_DISCONNECT_FINISHED,
 969                          GNUNET_TIME_UNIT_FOREVER_ABS);
 970   /* free addresses and mark as unused */
 971   unset_primary_address (n);
 972
 973   if (NULL != n->alternative_address.address)
 974   {
 975     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 976                 "Cleaning up alternative address\n");
 977     free_address (&n->alternative_address);
 978   }
 979   GNUNET_assert (GNUNET_YES ==
 980                  GNUNET_CONTAINER_multipeermap_remove (neighbours,
 981                                                        &n->id, n));
 982
 983   /* Cancel address requests for this peer */
 984   if (NULL != n->suggest_handle)
 985   {
 986     GNUNET_ATS_connectivity_suggest_cancel (n->suggest_handle);
 987     n->suggest_handle = NULL;
 988   }
 989
 990   /* Cancel the disconnect task */
 991   if (NULL != n->delayed_disconnect_task)
 992   {
 993     GNUNET_SCHEDULER_cancel (n->delayed_disconnect_task);
 994     n->delayed_disconnect_task = NULL;
 995   }
 996
 997   /* Cancel the master task */
 998   if (NULL != n->task)
 999   {
1000     GNUNET_SCHEDULER_cancel (n->task);
1001     n->task = NULL;
1002   }
1003   /* free rest of memory */
1004   GNUNET_free (n);
1005 }
1006
1007
1008 /**
1009  * Transmit a message using the current session of the given
1010  * neighbour.
1011  *
1012  * @param n entry for the recipient
1013  * @param msgbuf buffer to transmit
1014  * @param msgbuf_size number of bytes in @a msgbuf buffer
1015  * @param priority transmission priority
1016  * @param timeout transmission timeout
1017  * @param use_keepalive_timeout #GNUNET_YES to use plugin-specific keep-alive
1018  *        timeout (@a timeout is ignored in that case), #GNUNET_NO otherwise
1019  * @param cont continuation to call when finished (can be NULL)
1020  * @param cont_cls closure for @a cont
1021  * @return timeout (copy of @a timeout or a calculated one if
1022  *         @a use_keepalive_timeout is #GNUNET_YES.
1023  */
1024 static struct GNUNET_TIME_Relative
1025 send_with_session (struct NeighbourMapEntry *n,
1026                    const void *msgbuf,
1027                    size_t msgbuf_size,
1028                    uint32_t priority,
1029                    struct GNUNET_TIME_Relative timeout,
1030                    unsigned int use_keepalive_timeout,
1031                    GNUNET_TRANSPORT_TransmitContinuation cont,
1032                    void *cont_cls)
1033 {
1034   struct GNUNET_TRANSPORT_PluginFunctions *papi;
1035   struct GNUNET_TIME_Relative result = GNUNET_TIME_UNIT_FOREVER_REL;
1036
1037   GNUNET_assert (n->primary_address.session != NULL);
1038   if ( ((NULL == (papi = GST_plugins_find (n->primary_address.address->transport_name)) ||
1039          (-1 == papi->send (papi->cls,
1040                             n->primary_address.session,
1041                             msgbuf,
1042                             msgbuf_size,
1043                             priority,
1044                             (result = (GNUNET_NO == use_keepalive_timeout) ? timeout :
1045                              GNUNET_TIME_relative_divide (GNUNET_CONSTANTS_IDLE_CONNECTION_TIMEOUT,
1046                                                           papi->query_keepalive_factor (papi->cls))),
1047                             cont,
1048                             cont_cls)))) &&
1049        (NULL != cont))
1050     cont (cont_cls,
1051           &n->id,
1052           GNUNET_SYSERR,
1053           msgbuf_size,
1054           0);
1055   GST_neighbours_notify_data_sent (n->primary_address.address,
1056                                    n->primary_address.session,
1057                                    msgbuf_size);
1058   GNUNET_break (NULL != papi);
1059   return result;
1060 }
1061
1062
1063 /**
1064  * Function called when the 'DISCONNECT' message has been sent by the
1065  * plugin.  Frees the neighbour --- if the entry still exists.
1066  *
1067  * @param cls NULL
1068  * @param target identity of the neighbour that was disconnected
1069  * @param result #GNUNET_OK if the disconnect got out successfully
1070  * @param payload bytes payload
1071  * @param physical bytes on wire
1072  */
1073 static void
1074 send_disconnect_cont (void *cls,
1075                       const struct GNUNET_PeerIdentity *target,
1076                       int result,
1077                       size_t payload,
1078                       size_t physical)
1079 {
1080   struct NeighbourMapEntry *n;
1081
1082   n = lookup_neighbour (target);
1083   if (NULL == n)
1084     return; /* already gone */
1085   if (GNUNET_TRANSPORT_PS_DISCONNECT != n->state)
1086     return; /* have created a fresh entry since */
1087   if (NULL != n->task)
1088     GNUNET_SCHEDULER_cancel (n->task);
1089   n->task = GNUNET_SCHEDULER_add_now (&master_task, n);
1090 }
1091
1092
1093 /**
1094  * Transmit a DISCONNECT message to the other peer.
1095  *
1096  * @param n neighbour to send DISCONNECT message.
1097  */
1098 static void
1099 send_disconnect (struct NeighbourMapEntry *n)
1100 {
1101   struct SessionDisconnectMessage disconnect_msg;
1102
1103   GNUNET_log (GNUNET_ERROR_TYPE_INFO,
1104               "Sending DISCONNECT message to peer `%4s'\n",
1105               GNUNET_i2s (&n->id));
1106   disconnect_msg.header.size = htons (sizeof (struct SessionDisconnectMessage));
1107   disconnect_msg.header.type =
1108       htons (GNUNET_MESSAGE_TYPE_TRANSPORT_SESSION_DISCONNECT);
1109   disconnect_msg.reserved = htonl (0);
1110   disconnect_msg.purpose.size =
1111       htonl (sizeof (struct GNUNET_CRYPTO_EccSignaturePurpose) +
1112              sizeof (struct GNUNET_CRYPTO_EddsaPublicKey) +
1113              sizeof (struct GNUNET_TIME_AbsoluteNBO));
1114   disconnect_msg.purpose.purpose =
1115       htonl (GNUNET_MESSAGE_TYPE_TRANSPORT_SESSION_DISCONNECT);
1116   disconnect_msg.timestamp =
1117       GNUNET_TIME_absolute_hton (GNUNET_TIME_absolute_get ());
1118   disconnect_msg.public_key = GST_my_identity.public_key;
1119   GNUNET_assert (GNUNET_OK ==
1120                  GNUNET_CRYPTO_eddsa_sign (GST_my_private_key,
1121                                          &disconnect_msg.purpose,
1122                                          &disconnect_msg.signature));
1123
1124   (void) send_with_session (n,
1125                             &disconnect_msg,
1126                             sizeof (disconnect_msg),
1127                             UINT32_MAX,
1128                             GNUNET_TIME_UNIT_FOREVER_REL,
1129                             GNUNET_NO,
1130                             &send_disconnect_cont,
1131                             NULL);
1132   GNUNET_STATISTICS_update (GST_stats,
1133                             gettext_noop ("# DISCONNECT messages sent"),
1134                             1,
1135                             GNUNET_NO);
1136 }
1137
1138
1139 /**
1140  * Disconnect from the given neighbour, clean up the record.
1141  *
1142  * @param n neighbour to disconnect from
1143  */
1144 static void
1145 disconnect_neighbour (struct NeighbourMapEntry *n)
1146 {
1147   GNUNET_log (GNUNET_ERROR_TYPE_INFO,
1148               "Disconnecting from peer %s in state %s\n",
1149               GNUNET_i2s (&n->id),
1150               GNUNET_TRANSPORT_ps2s (n->state));
1151   /* depending on state, notify neighbour and/or upper layers of this peer
1152      about disconnect */
1153   switch (n->state)
1154   {
1155   case GNUNET_TRANSPORT_PS_NOT_CONNECTED:
1156   case GNUNET_TRANSPORT_PS_INIT_ATS:
1157     /* other peer is completely unaware of us, no need to send DISCONNECT */
1158     free_neighbour (n);
1159     return;
1160   case GNUNET_TRANSPORT_PS_SYN_SENT:
1161     send_disconnect (n);
1162     set_state_and_timeout (n,
1163                            GNUNET_TRANSPORT_PS_DISCONNECT,
1164                            GNUNET_TIME_UNIT_FOREVER_ABS);
1165     break;
1166   case GNUNET_TRANSPORT_PS_SYN_RECV_ATS:
1167     /* we never ACK'ed the other peer's request, no need to send DISCONNECT */
1168     free_neighbour (n);
1169     return;
1170   case GNUNET_TRANSPORT_PS_SYN_RECV_ACK:
1171     /* we DID ACK the other peer's request, must send DISCONNECT */
1172     send_disconnect (n);
1173     set_state_and_timeout (n,
1174                            GNUNET_TRANSPORT_PS_DISCONNECT,
1175                            GNUNET_TIME_UNIT_FOREVER_ABS);
1176     break;
1177   case GNUNET_TRANSPORT_PS_SWITCH_SYN_SENT:
1178   case GNUNET_TRANSPORT_PS_CONNECTED:
1179   case GNUNET_TRANSPORT_PS_RECONNECT_SENT:
1180     /* we are currently connected, need to send disconnect and do
1181        internal notifications and update statistics */
1182     send_disconnect (n);
1183     set_state_and_timeout (n,
1184                            GNUNET_TRANSPORT_PS_DISCONNECT,
1185                            GNUNET_TIME_UNIT_FOREVER_ABS);
1186     break;
1187   case GNUNET_TRANSPORT_PS_RECONNECT_ATS:
1188     /* Disconnecting while waiting for an ATS address to reconnect,
1189      * cannot send DISCONNECT */
1190     free_neighbour (n);
1191     return;
1192   case GNUNET_TRANSPORT_PS_DISCONNECT:
1193     /* already disconnected, ignore */
1194     break;
1195   case GNUNET_TRANSPORT_PS_DISCONNECT_FINISHED:
1196     /* already cleaned up, how did we get here!? */
1197     GNUNET_assert (0);
1198     break;
1199   default:
1200     GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
1201                 "Unhandled state `%s'\n",
1202                 GNUNET_TRANSPORT_ps2s (n->state));
1203     GNUNET_break (0);
1204     break;
1205   }
1206   /* schedule timeout to clean up */
1207   if (NULL != n->task)
1208     GNUNET_SCHEDULER_cancel (n->task);
1209   n->task = GNUNET_SCHEDULER_add_delayed (DISCONNECT_SENT_TIMEOUT,
1210                                           &master_task,
1211                                           n);
1212 }
1213
1214
1215 /**
1216  * We're done with our transmission attempt, continue processing.
1217  *
1218  * @param cls the `struct MessageQueue` of the message
1219  * @param receiver intended receiver
1220  * @param success whether it worked or not
1221  * @param size_payload bytes payload sent
1222  * @param physical bytes sent on wire
1223  */
1224 static void
1225 transmit_send_continuation (void *cls,
1226                             const struct GNUNET_PeerIdentity *receiver,
1227                             int success, size_t size_payload, size_t physical)
1228 {
1229   struct MessageQueue *mq = cls;
1230   struct NeighbourMapEntry *n;
1231
1232   if (NULL == (n = lookup_neighbour (receiver)))
1233   {
1234     GNUNET_free (mq);
1235     return; /* disconnect or other error while transmitting, can happen */
1236   }
1237   if (n->is_active == mq)
1238   {
1239     /* this is still "our" neighbour, remove us from its queue
1240        and allow it to send the next message now */
1241     n->is_active = NULL;
1242     if (NULL != n->task)
1243       GNUNET_SCHEDULER_cancel (n->task);
1244     n->task = GNUNET_SCHEDULER_add_now (&master_task, n);
1245   }
1246   if (bytes_in_send_queue < mq->message_buf_size)
1247   {
1248     GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
1249                 "Bytes_in_send_queue `%u', Message_size %u, result: %s, payload %u, on wire %u\n",
1250                 bytes_in_send_queue,
1251                 mq->message_buf_size,
1252                 (GNUNET_OK == success) ? "OK" : "FAIL",
1253                 size_payload,
1254                 physical);
1255     GNUNET_break (0);
1256   }
1257
1258
1259   GNUNET_break (size_payload == mq->message_buf_size);
1260   bytes_in_send_queue -= mq->message_buf_size;
1261   GNUNET_STATISTICS_set (GST_stats,
1262                         gettext_noop
1263                          ("# bytes in message queue for other peers"),
1264                          bytes_in_send_queue, GNUNET_NO);
1265   if (GNUNET_OK == success)
1266     GNUNET_STATISTICS_update (GST_stats,
1267                               gettext_noop
1268                               ("# messages transmitted to other peers"),
1269                               1, GNUNET_NO);
1270   else
1271     GNUNET_STATISTICS_update (GST_stats,
1272                               gettext_noop
1273                               ("# transmission failures for messages to other peers"),
1274                               1, GNUNET_NO);
1275   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1276               "Sending message to `%s' of type %u with %u bytes was a %s\n",
1277               GNUNET_i2s (receiver),
1278               ntohs (((struct GNUNET_MessageHeader *) mq->message_buf)->type),
1279               mq->message_buf_size,
1280               (success == GNUNET_OK) ? "success" : "FAILURE");
1281   if (NULL != mq->cont)
1282     mq->cont (mq->cont_cls, success, size_payload, physical);
1283   GNUNET_free (mq);
1284 }
1285
1286
1287 /**
1288  * Check the message list for the given neighbour and if we can
1289  * send a message, do so.  This function should only be called
1290  * if the connection is at least generally ready for transmission.
1291  * While we will only send one message at a time, no bandwidth
1292  * quota management is performed here.  If a message was given to
1293  * the plugin, the continuation will automatically re-schedule
1294  * the 'master' task once the next message might be transmitted.
1295  *
1296  * @param n target peer for which to transmit
1297  */
1298 static void
1299 try_transmission_to_peer (struct NeighbourMapEntry *n)
1300 {
1301   struct MessageQueue *mq;
1302   struct GNUNET_TIME_Relative timeout;
1303
1304   if (NULL == n->primary_address.address)
1305   {
1306     /* no address, why are we here? */
1307     GNUNET_break (0);
1308     return;
1309   }
1310   if ((0 == n->primary_address.address->address_length) &&
1311       (NULL == n->primary_address.session))
1312   {
1313     /* no address, why are we here? */
1314     GNUNET_break (0);
1315     return;
1316   }
1317   if (NULL != n->is_active)
1318   {
1319     /* transmission already pending */
1320     return;
1321   }
1322
1323   /* timeout messages from the queue that are past their due date */
1324   while (NULL != (mq = n->messages_head))
1325   {
1326     timeout = GNUNET_TIME_absolute_get_remaining (mq->timeout);
1327     if (timeout.rel_value_us > 0)
1328       break;
1329     GNUNET_STATISTICS_update (GST_stats,
1330                               gettext_noop
1331                               ("# messages timed out while in transport queue"),
1332                               1, GNUNET_NO);
1333     GNUNET_CONTAINER_DLL_remove (n->messages_head,
1334                                  n->messages_tail,
1335                                  mq);
1336     n->is_active = mq;
1337     transmit_send_continuation (mq,
1338                                 &n->id,
1339                                 GNUNET_SYSERR,
1340                                 mq->message_buf_size,
1341                                 0);     /* timeout */
1342   }
1343   if (NULL == mq)
1344     return;                     /* no more messages */
1345   GNUNET_CONTAINER_DLL_remove (n->messages_head,
1346                                n->messages_tail,
1347                                mq);
1348   n->is_active = mq;
1349
1350   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1351               "Giving message with %u bytes to plugin session %p\n",
1352               mq->message_buf_size,
1353               n->primary_address.session);
1354   (void) send_with_session (n,
1355                             mq->message_buf,
1356                             mq->message_buf_size,
1357                             0 /* priority */,
1358                             timeout,
1359                             GNUNET_NO,
1360                             &transmit_send_continuation,
1361                             mq);
1362 }
1363
1364
1365 /**
1366  * Send keepalive message to the neighbour.  Must only be called
1367  * if we are on 'connected' state or while trying to switch addresses.
1368  * Will internally determine if a keepalive is truly needed (so can
1369  * always be called).
1370  *
1371  * @param n neighbour that went idle and needs a keepalive
1372  */
1373 static void
1374 send_keepalive (struct NeighbourMapEntry *n)
1375 {
1376   struct SessionKeepAliveMessage m;
1377   struct GNUNET_TIME_Relative timeout;
1378   uint32_t nonce;
1379
1380   GNUNET_assert ((GNUNET_TRANSPORT_PS_CONNECTED == n->state) ||
1381                  (GNUNET_TRANSPORT_PS_SWITCH_SYN_SENT == n->state));
1382   if (GNUNET_TIME_absolute_get_remaining (n->keep_alive_time).rel_value_us > 0)
1383     return; /* no keepalive needed at this time */
1384
1385   nonce = 0; /* 0 indicates 'not set' */
1386   while (0 == nonce)
1387     nonce = GNUNET_CRYPTO_random_u32 (GNUNET_CRYPTO_QUALITY_NONCE, UINT32_MAX);
1388
1389   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1390               "Sending keep alive to peer `%s' with nonce %u\n",
1391               GNUNET_i2s (&n->id),
1392               nonce);
1393   m.header.size = htons (sizeof (struct SessionKeepAliveMessage));
1394   m.header.type = htons (GNUNET_MESSAGE_TYPE_TRANSPORT_SESSION_KEEPALIVE);
1395   m.nonce = htonl (nonce);
1396
1397   timeout = send_with_session (n,
1398                                &m,
1399                                sizeof (m),
1400                                UINT32_MAX /* priority */,
1401                                GNUNET_TIME_UNIT_FOREVER_REL,
1402                                GNUNET_YES,
1403                                NULL, NULL);
1404   GNUNET_STATISTICS_update (GST_stats,
1405                             gettext_noop ("# keepalives sent"),
1406                             1,
1407                             GNUNET_NO);
1408   n->primary_address.keep_alive_nonce = nonce;
1409   n->expect_latency_response = GNUNET_YES;
1410   n->last_keep_alive_time = GNUNET_TIME_absolute_get ();
1411   n->keep_alive_time = GNUNET_TIME_relative_to_absolute (timeout);
1412 }
1413
1414
1415 /**
1416  * Keep the connection to the given neighbour alive longer,
1417  * we received a KEEPALIVE (or equivalent); send a response.
1418  *
1419  * @param neighbour neighbour to keep alive (by sending keep alive response)
1420  * @param m the keep alive message containing the nonce to respond to
1421  */
1422 void
1423 GST_neighbours_keepalive (const struct GNUNET_PeerIdentity *neighbour,
1424                           const struct GNUNET_MessageHeader *m)
1425 {
1426   struct NeighbourMapEntry *n;
1427   const struct SessionKeepAliveMessage *msg_in;
1428   struct SessionKeepAliveMessage msg;
1429
1430   if (sizeof (struct SessionKeepAliveMessage) != ntohs (m->size))
1431     return;
1432
1433   msg_in = (struct SessionKeepAliveMessage *) m;
1434   if (NULL == (n = lookup_neighbour (neighbour)))
1435   {
1436     GNUNET_STATISTICS_update (GST_stats,
1437                               gettext_noop
1438                               ("# KEEPALIVE messages discarded (peer unknown)"),
1439                               1, GNUNET_NO);
1440     return;
1441   }
1442   if (NULL == n->primary_address.session)
1443   {
1444     GNUNET_STATISTICS_update (GST_stats,
1445                               gettext_noop
1446                               ("# KEEPALIVE messages discarded (no session)"),
1447                               1, GNUNET_NO);
1448     return;
1449   }
1450
1451   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1452       "Received keep alive request from peer `%s' with nonce %u\n",
1453       GNUNET_i2s (&n->id), ntohl (msg_in->nonce));
1454
1455   /* send reply to allow neighbour to measure latency */
1456   msg.header.size = htons (sizeof (struct SessionKeepAliveMessage));
1457   msg.header.type = htons (GNUNET_MESSAGE_TYPE_TRANSPORT_SESSION_KEEPALIVE_RESPONSE);
1458   msg.nonce = msg_in->nonce;
1459   (void) send_with_session (n,
1460                             &msg,
1461                             sizeof (struct SessionKeepAliveMessage),
1462                             UINT32_MAX /* priority */,
1463                             GNUNET_TIME_UNIT_FOREVER_REL,
1464                             GNUNET_YES,
1465                             NULL, NULL);
1466 }
1467
1468
1469 /**
1470  * We received a KEEP_ALIVE_RESPONSE message and use this to calculate
1471  * latency to this peer.  Pass the updated information (existing ats
1472  * plus calculated latency) to ATS.
1473  *
1474  * @param neighbour neighbour to keep alive
1475  * @param m the message containing the keep alive response
1476  */
1477 void
1478 GST_neighbours_keepalive_response (const struct GNUNET_PeerIdentity *neighbour,
1479                                    const struct GNUNET_MessageHeader *m)
1480 {
1481   struct NeighbourMapEntry *n;
1482   const struct SessionKeepAliveMessage *msg;
1483   struct GNUNET_TRANSPORT_PluginFunctions *papi;
1484   struct GNUNET_ATS_Information ats;
1485   struct GNUNET_TIME_Relative latency;
1486
1487   if (sizeof (struct SessionKeepAliveMessage) != ntohs (m->size))
1488     return;
1489
1490   msg = (const struct SessionKeepAliveMessage *) m;
1491   if (NULL == (n = lookup_neighbour (neighbour)))
1492   {
1493     GNUNET_STATISTICS_update (GST_stats,
1494                               gettext_noop
1495                               ("# KEEPALIVE_RESPONSE messages discarded (not connected)"),
1496                               1, GNUNET_NO);
1497     return;
1498   }
1499   if ( (GNUNET_TRANSPORT_PS_CONNECTED != n->state) ||
1500        (GNUNET_YES != n->expect_latency_response) )
1501   {
1502     GNUNET_STATISTICS_update (GST_stats,
1503                               gettext_noop
1504                               ("# KEEPALIVE_RESPONSE messages discarded (not expected)"),
1505                               1, GNUNET_NO);
1506     return;
1507   }
1508   if (NULL == n->primary_address.address)
1509   {
1510     GNUNET_STATISTICS_update (GST_stats,
1511                               gettext_noop
1512                               ("# KEEPALIVE_RESPONSE messages discarded (address changed)"),
1513                               1, GNUNET_NO);
1514     return;
1515   }
1516   if (n->primary_address.keep_alive_nonce != ntohl (msg->nonce))
1517   {
1518     GNUNET_STATISTICS_update (GST_stats,
1519                               gettext_noop
1520                               ("# KEEPALIVE_RESPONSE messages discarded (wrong nonce)"),
1521                               1, GNUNET_NO);
1522     return;
1523   }
1524   else
1525   {
1526     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1527         "Received keep alive response from peer `%s' for session %p\n",
1528         GNUNET_i2s (&n->id), n->primary_address.session);
1529
1530   }
1531
1532   /* Update session timeout here */
1533   if (NULL != (papi = GST_plugins_find (n->primary_address.address->transport_name)))
1534   {
1535     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1536         "Updating session for peer `%s' for session %p\n",
1537         GNUNET_i2s (&n->id), n->primary_address.session);
1538     papi->update_session_timeout (papi->cls, &n->id, n->primary_address.session);
1539   }
1540   else
1541   {
1542     GNUNET_break (0);
1543   }
1544
1545   n->primary_address.keep_alive_nonce = 0;
1546   n->expect_latency_response = GNUNET_NO;
1547   set_state_and_timeout (n,
1548                          n->state,
1549                          GNUNET_TIME_relative_to_absolute (GNUNET_CONSTANTS_IDLE_CONNECTION_TIMEOUT));
1550
1551   latency = GNUNET_TIME_absolute_get_duration (n->last_keep_alive_time);
1552   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1553               "Latency for peer `%s' is %s\n",
1554               GNUNET_i2s (&n->id),
1555               GNUNET_STRINGS_relative_time_to_string (latency,
1556                                                       GNUNET_YES));
1557   /* append latency */
1558   ats.type = htonl (GNUNET_ATS_QUALITY_NET_DELAY);
1559   ats.value = htonl ( (latency.rel_value_us > UINT32_MAX)
1560                       ? UINT32_MAX
1561                       : (uint32_t) latency.rel_value_us );
1562   GST_ats_update_metrics (n->primary_address.address,
1563                           n->primary_address.session,
1564                           &ats, 1);
1565 }
1566
1567
1568 /**
1569  * We have received a message from the given sender.  How long should
1570  * we delay before receiving more?  (Also used to keep the peer marked
1571  * as live).
1572  *
1573  * @param sender sender of the message
1574  * @param size size of the message
1575  * @param do_forward set to #GNUNET_YES if the message should be forwarded to clients
1576  *                   #GNUNET_NO if the neighbour is not connected or violates the quota,
1577  *                   #GNUNET_SYSERR if the connection is not fully up yet
1578  * @return how long to wait before reading more from this sender
1579  */
1580 struct GNUNET_TIME_Relative
1581 GST_neighbours_calculate_receive_delay (const struct GNUNET_PeerIdentity
1582                                         *sender, ssize_t size, int *do_forward)
1583 {
1584   struct NeighbourMapEntry *n;
1585   struct GNUNET_TIME_Relative ret;
1586
1587   if (NULL == neighbours)
1588   {
1589     *do_forward = GNUNET_NO;
1590     return GNUNET_TIME_UNIT_FOREVER_REL; /* This can happen during shutdown */
1591   }
1592   if (NULL == (n = lookup_neighbour (sender)))
1593   {
1594     GST_neighbours_try_connect (sender);
1595     if (NULL == (n = lookup_neighbour (sender)))
1596     {
1597       GNUNET_STATISTICS_update (GST_stats,
1598                                 gettext_noop
1599                                 ("# messages discarded due to lack of neighbour record"),
1600                                 1, GNUNET_NO);
1601       *do_forward = GNUNET_NO;
1602       return GNUNET_TIME_UNIT_ZERO;
1603     }
1604   }
1605   if (! test_connected (n))
1606   {
1607     *do_forward = GNUNET_SYSERR;
1608     return GNUNET_TIME_UNIT_ZERO;
1609   }
1610   if (GNUNET_YES == GNUNET_BANDWIDTH_tracker_consume (&n->in_tracker, size))
1611   {
1612     n->quota_violation_count++;
1613     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1614                 "Bandwidth quota (%u b/s) violation detected (total of %u).\n",
1615                 n->in_tracker.available_bytes_per_s__,
1616                 n->quota_violation_count);
1617     /* Discount 32k per violation */
1618     GNUNET_BANDWIDTH_tracker_consume (&n->in_tracker, -32 * 1024);
1619   }
1620   else
1621   {
1622     if (n->quota_violation_count > 0)
1623     {
1624       /* try to add 32k back */
1625       GNUNET_BANDWIDTH_tracker_consume (&n->in_tracker, 32 * 1024);
1626       n->quota_violation_count--;
1627     }
1628   }
1629   if (n->quota_violation_count > QUOTA_VIOLATION_DROP_THRESHOLD)
1630   {
1631     GNUNET_STATISTICS_update (GST_stats,
1632                               gettext_noop
1633                               ("# bandwidth quota violations by other peers"),
1634                               1, GNUNET_NO);
1635     *do_forward = GNUNET_NO;
1636     return GNUNET_CONSTANTS_QUOTA_VIOLATION_TIMEOUT;
1637   }
1638   *do_forward = GNUNET_YES;
1639   ret = GNUNET_BANDWIDTH_tracker_get_delay (&n->in_tracker, 32 * 1024);
1640   if (ret.rel_value_us > 0)
1641   {
1642     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1643                 "Throttling read (%lld bytes excess at %u b/s), waiting %s before reading more.\n",
1644                 (long long) n->in_tracker.consumption_since_last_update__,
1645                 (unsigned int) n->in_tracker.available_bytes_per_s__,
1646                 GNUNET_STRINGS_relative_time_to_string (ret, GNUNET_YES));
1647     GNUNET_STATISTICS_update (GST_stats,
1648                               gettext_noop ("# ms throttling suggested"),
1649                               (int64_t) ret.rel_value_us / 1000LL,
1650                               GNUNET_NO);
1651   }
1652   return ret;
1653 }
1654
1655
1656 /**
1657  * Transmit a message to the given target using the active connection.
1658  *
1659  * @param target destination
1660  * @param msg message to send
1661  * @param msg_size number of bytes in msg
1662  * @param timeout when to fail with timeout
1663  * @param cont function to call when done
1664  * @param cont_cls closure for @a cont
1665  */
1666 void
1667 GST_neighbours_send (const struct GNUNET_PeerIdentity *target,
1668                      const void *msg,
1669                      size_t msg_size,
1670                      struct GNUNET_TIME_Relative timeout,
1671                      GST_NeighbourSendContinuation cont,
1672                      void *cont_cls)
1673 {
1674   struct NeighbourMapEntry *n;
1675   struct MessageQueue *mq;
1676
1677   /* All ove these cases should never happen; they are all API violations.
1678      But we check anyway, just to be sure. */
1679   if (NULL == (n = lookup_neighbour (target)))
1680   {
1681     GNUNET_break (0);
1682     if (NULL != cont)
1683       cont (cont_cls, GNUNET_SYSERR, msg_size, 0);
1684     return;
1685   }
1686   if (GNUNET_YES != test_connected (n))
1687   {
1688     GNUNET_break (0);
1689     if (NULL != cont)
1690       cont (cont_cls, GNUNET_SYSERR, msg_size, 0);
1691     return;
1692   }
1693   bytes_in_send_queue += msg_size;
1694   GNUNET_STATISTICS_set (GST_stats,
1695                          gettext_noop
1696                          ("# bytes in message queue for other peers"),
1697                          bytes_in_send_queue, GNUNET_NO);
1698   mq = GNUNET_malloc (sizeof (struct MessageQueue) + msg_size);
1699   mq->cont = cont;
1700   mq->cont_cls = cont_cls;
1701   memcpy (&mq[1], msg, msg_size);
1702   mq->message_buf = (const char *) &mq[1];
1703   mq->message_buf_size = msg_size;
1704   mq->timeout = GNUNET_TIME_relative_to_absolute (timeout);
1705
1706   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Enqueueing %u bytes to send to peer %s\n",
1707       msg_size, GNUNET_i2s (target));
1708
1709   GNUNET_CONTAINER_DLL_insert_tail (n->messages_head, n->messages_tail, mq);
1710   if (NULL != n->task)
1711     GNUNET_SCHEDULER_cancel (n->task);
1712   n->task = GNUNET_SCHEDULER_add_now (&master_task, n);
1713 }
1714
1715
1716 /**
1717  * Continuation called from our attempt to transmitted our
1718  * #GNUNET_MESSAGE_TYPE_TRANSPORT_SESSION_SYN to the specified @a
1719  * target.  Continue processing based on the @a result.  Specifically,
1720  * if we failed to transmit, discard the address we used.
1721  *
1722  * @param cls NULL
1723  * @param target which peer received the transmission
1724  * @param result #GNUNET_OK if sending worked
1725  * @param size_payload how many bytes of payload were sent (ignored)
1726  * @param size_on_wire how much bandwidth was consumed on the wire (ignored)
1727  */
1728 static void
1729 send_session_syn_cont (void *cls,
1730                        const struct GNUNET_PeerIdentity *target,
1731                        int result,
1732                        size_t size_payload,
1733                        size_t size_on_wire)
1734 {
1735   struct NeighbourMapEntry *n;
1736
1737   n = lookup_neighbour (target);
1738   if (NULL == n)
1739   {
1740     /* SYN continuation was called after neighbor was freed,
1741      * for example due to a time out for the state or the session
1742      * used was already terminated: nothing to do here... */
1743     return;
1744   }
1745
1746   if ( (GNUNET_TRANSPORT_PS_SYN_SENT != n->state) &&
1747        (GNUNET_TRANSPORT_PS_RECONNECT_SENT != n->state) &&
1748        (GNUNET_TRANSPORT_PS_SWITCH_SYN_SENT != n->state))
1749   {
1750     /* SYN continuation was called after neighbor changed state,
1751      * for example due to a time out for the state or the session
1752      * used was already terminated: nothing to do here... */
1753     return;
1754   }
1755   if (GNUNET_OK == result)
1756     return;
1757
1758   GNUNET_log (GNUNET_ERROR_TYPE_INFO,
1759               _("Failed to send SYN message to peer `%s'\n"),
1760               GNUNET_i2s (target));
1761   switch (n->state) {
1762   case GNUNET_TRANSPORT_PS_SYN_SENT:
1763     /* Remove address and request an additional one */
1764     unset_primary_address (n);
1765     set_state_and_timeout (n,
1766                            GNUNET_TRANSPORT_PS_INIT_ATS,
1767                            GNUNET_TIME_relative_to_absolute (FAST_RECONNECT_TIMEOUT));
1768     break;
1769   case GNUNET_TRANSPORT_PS_RECONNECT_SENT:
1770     /* Remove address and request an additional one */
1771     unset_primary_address (n);
1772     set_state_and_timeout (n,
1773                            GNUNET_TRANSPORT_PS_RECONNECT_ATS,
1774                            GNUNET_TIME_relative_to_absolute (ATS_RESPONSE_TIMEOUT));
1775     break;
1776   case GNUNET_TRANSPORT_PS_SWITCH_SYN_SENT:
1777     /* Remove address and request and go back to primary address */
1778     GNUNET_STATISTICS_update (GST_stats,
1779                               gettext_noop ("# Failed attempts to switch addresses (failed to send SYN CONT)"),
1780                               1,
1781                               GNUNET_NO);
1782     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1783                 "Switch failed, cleaning up alternative address\n");
1784     free_address (&n->alternative_address);
1785     set_state_and_timeout (n,
1786                            GNUNET_TRANSPORT_PS_CONNECTED,
1787                            GNUNET_TIME_relative_to_absolute (ATS_RESPONSE_TIMEOUT));
1788     break;
1789   default:
1790     disconnect_neighbour (n);
1791     break;
1792   }
1793 }
1794
1795
1796 /**
1797  * Send a SYN message via the given address.
1798  *
1799  * @param na address to use
1800  */
1801 static void
1802 send_syn (struct NeighbourAddress *na)
1803 {
1804   struct GNUNET_TRANSPORT_PluginFunctions *papi;
1805   struct TransportSynMessage connect_msg;
1806   struct NeighbourMapEntry *n;
1807
1808   GNUNET_assert (NULL != na->session);
1809   GNUNET_log (GNUNET_ERROR_TYPE_INFO,
1810               "Sending SYN message to peer `%s' at %s\n",
1811               GNUNET_i2s (&na->address->peer),
1812               GST_plugins_a2s (na->address));
1813
1814   papi = GST_plugins_find (na->address->transport_name);
1815   GNUNET_assert (NULL != papi);
1816   GNUNET_STATISTICS_update (GST_stats,
1817                             gettext_noop
1818                             ("# SYN messages sent"),
1819                             1, GNUNET_NO);
1820   na->connect_timestamp = GNUNET_TIME_absolute_get ();
1821   connect_msg.header.size = htons (sizeof (struct TransportSynMessage));
1822   connect_msg.header.type = htons (GNUNET_MESSAGE_TYPE_TRANSPORT_SESSION_SYN);
1823   connect_msg.reserved = htonl (0);
1824   connect_msg.timestamp = GNUNET_TIME_absolute_hton (na->connect_timestamp);
1825   if (-1 ==
1826       papi->send (papi->cls,
1827                   na->session,
1828                   (const char *) &connect_msg,
1829                   sizeof (struct TransportSynMessage),
1830                   UINT_MAX,
1831                   SETUP_CONNECTION_TIMEOUT,
1832                   &send_session_syn_cont, NULL))
1833   {
1834     GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
1835                 _("Failed to transmit SYN message to %s\n"),
1836                 GST_plugins_a2s (na->address));
1837     n = lookup_neighbour (&na->address->peer);
1838     if (NULL == n)
1839     {
1840       GNUNET_break (0);
1841       return;
1842     }
1843     switch (n->state) {
1844       case GNUNET_TRANSPORT_PS_SYN_SENT:
1845         /* Remove address and request and additional one */
1846         GNUNET_assert (na == &n->primary_address);
1847         unset_primary_address (n);
1848         set_state_and_timeout (n,
1849                                GNUNET_TRANSPORT_PS_INIT_ATS,
1850                                GNUNET_TIME_relative_to_absolute (FAST_RECONNECT_TIMEOUT));
1851         /* Hard failure to send the SYN message with this address:
1852            Destroy address and session */
1853         break;
1854       case GNUNET_TRANSPORT_PS_RECONNECT_SENT:
1855         /* Remove address and request an additional one */
1856         GNUNET_assert (na == &n->primary_address);
1857         unset_primary_address (n);
1858         set_state_and_timeout (n,
1859                                GNUNET_TRANSPORT_PS_RECONNECT_ATS,
1860                                GNUNET_TIME_relative_to_absolute (ATS_RESPONSE_TIMEOUT));
1861         break;
1862       case GNUNET_TRANSPORT_PS_SWITCH_SYN_SENT:
1863         GNUNET_assert (na == &n->alternative_address);
1864         GNUNET_STATISTICS_update (GST_stats,
1865                                   gettext_noop ("# Failed attempts to switch addresses (failed to send SYN)"),
1866                                   1,
1867                                   GNUNET_NO);
1868         /* Remove address and request an additional one */
1869         GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1870                     "Switch failed, cleaning up alternative address\n");
1871         free_address (&n->alternative_address);
1872         set_state_and_timeout (n,
1873                                GNUNET_TRANSPORT_PS_CONNECTED,
1874                                GNUNET_TIME_relative_to_absolute (ATS_RESPONSE_TIMEOUT));
1875         break;
1876       default:
1877         GNUNET_break (0);
1878         disconnect_neighbour (n);
1879         break;
1880     }
1881     return;
1882   }
1883   GST_neighbours_notify_data_sent (na->address,
1884                                    na->session,
1885                                    sizeof (struct TransportSynMessage));
1886 }
1887
1888
1889 /**
1890  * Continuation called from our attempt to transmitted our
1891  * #GNUNET_MESSAGE_TYPE_TRANSPORT_SESSION_SYN_ACK to the specified @a
1892  * target.  Continue processing based on the @a result.  Specifically,
1893  * if we failed to transmit, discard the address we used.
1894  *
1895  * @param cls NULL
1896  * @param target which peer received the transmission
1897  * @param result #GNUNET_OK if sending worked
1898  * @param size_payload how many bytes of payload were sent (ignored)
1899  * @param size_on_wire how much bandwidth was consumed on the wire (ignored)
1900  */
1901 static void
1902 send_session_syn_ack_cont (void *cls,
1903                            const struct GNUNET_PeerIdentity *target,
1904                            int result,
1905                            size_t size_payload,
1906                            size_t size_on_wire)
1907 {
1908   struct NeighbourMapEntry *n;
1909
1910   n = lookup_neighbour (target);
1911   if (NULL == n)
1912   {
1913     /* SYN_ACK continuation was called after neighbor was freed,
1914      * for example due to a time out for the state or the session
1915      * used was already terminated: nothing to do here... */
1916     return;
1917   }
1918
1919   if (GNUNET_TRANSPORT_PS_SYN_RECV_ACK != n->state)
1920   {
1921     /* SYN_ACK continuation was called after neighbor changed state,
1922      * for example due to a time out for the state or the session
1923      * used was already terminated: nothing to do here... */
1924     return;
1925   }
1926   if (GNUNET_OK == result)
1927     return;
1928
1929   GNUNET_log (GNUNET_ERROR_TYPE_INFO,
1930             _("Failed to send SYN_ACK message to peer `%s' using address `%s'\n"),
1931             GNUNET_i2s (target),
1932             GST_plugins_a2s (n->primary_address.address));
1933
1934   /* Remove address and request and additional one */
1935   /* FIXME: what if the neighbour's primary address
1936      changed in the meantime? Might want to instead
1937      pass "something" around in closure to be sure. */
1938   unset_primary_address (n);
1939   n->ack_state = ACK_SEND_SYN_ACK;
1940   set_state_and_timeout (n,
1941                          GNUNET_TRANSPORT_PS_SYN_RECV_ATS,
1942                          GNUNET_TIME_relative_to_absolute (ATS_RESPONSE_TIMEOUT));
1943 }
1944
1945
1946 /**
1947  * Send a SYN_ACK message via the given address.
1948  *
1949  * @param na address and session to use
1950  * @param timestamp timestamp to use for the ACK message
1951  * @return #GNUNET_SYSERR if sending immediately failed, #GNUNET_OK otherwise
1952  */
1953 static void
1954 send_syn_ack_message (struct NeighbourAddress *na,
1955                       struct GNUNET_TIME_Absolute timestamp)
1956 {
1957   const struct GNUNET_HELLO_Address *address = na->address;
1958   struct Session *session = na->session;
1959   struct GNUNET_TRANSPORT_PluginFunctions *papi;
1960   struct TransportSynMessage connect_msg;
1961   struct NeighbourMapEntry *n;
1962
1963   GNUNET_log (GNUNET_ERROR_TYPE_INFO,
1964               "Sending SYN_ACK to peer `%s'\n",
1965               GNUNET_i2s (&address->peer));
1966
1967   if (NULL == (papi = GST_plugins_find (address->transport_name)))
1968   {
1969     GNUNET_break (0);
1970     return;
1971   }
1972   if (NULL == session)
1973     session = papi->get_session (papi->cls,
1974                                  address);
1975   if (NULL == session)
1976   {
1977     GNUNET_break (0);
1978     return;
1979   }
1980   GST_ats_new_session (address,
1981                        session);
1982   GNUNET_STATISTICS_update (GST_stats,
1983                             gettext_noop
1984                             ("# SYN_ACK messages sent"),
1985                             1, GNUNET_NO);
1986   connect_msg.header.size = htons (sizeof (struct TransportSynMessage));
1987   connect_msg.header.type = htons (GNUNET_MESSAGE_TYPE_TRANSPORT_SESSION_SYN_ACK);
1988   connect_msg.reserved = htonl (0);
1989   connect_msg.timestamp = GNUNET_TIME_absolute_hton (timestamp);
1990
1991   if (GNUNET_SYSERR ==
1992       papi->send (papi->cls,
1993                   session,
1994                   (const char *) &connect_msg,
1995                   sizeof (struct TransportSynMessage),
1996                   UINT_MAX,
1997                   GNUNET_TIME_UNIT_FOREVER_REL,
1998                   &send_session_syn_ack_cont, NULL))
1999   {
2000     GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
2001                 _("Failed to transmit SYN_ACK message to %s\n"),
2002                 GST_plugins_a2s (address));
2003
2004     n = lookup_neighbour (&address->peer);
2005     if (NULL == n)
2006     {
2007       GNUNET_break (0);
2008       return;
2009     }
2010     /* Remove address and request and additional one */
2011     unset_primary_address (n);
2012     n->ack_state = ACK_SEND_SYN_ACK;
2013     set_state_and_timeout (n,
2014                            GNUNET_TRANSPORT_PS_SYN_RECV_ATS,
2015                            GNUNET_TIME_relative_to_absolute (ATS_RESPONSE_TIMEOUT));
2016     return;
2017   }
2018 }
2019
2020
2021 /**
2022  * Function called by the bandwidth tracker for a peer whenever
2023  * the tracker's state changed such that we need to recalculate
2024  * the delay for flow control.  We calculate the latest delay
2025  * and inform the plugin (if applicable).
2026  *
2027  * @param cls the `struct NeighbourMapEntry` to update calculations for
2028  */
2029 static void
2030 inbound_bw_tracker_update (void *cls)
2031 {
2032   struct NeighbourMapEntry *n = cls;
2033   struct GNUNET_TRANSPORT_PluginFunctions *papi;
2034   struct GNUNET_TIME_Relative delay;
2035   int do_forward;
2036
2037   if (NULL == n->primary_address.address)
2038     return; /* not active, ignore */
2039   papi = GST_plugins_find (n->primary_address.address->transport_name);
2040   GNUNET_assert (NULL != papi);
2041   if (NULL == papi->update_inbound_delay)
2042     return;
2043   delay = GST_neighbours_calculate_receive_delay (&n->id,
2044                                                   0,
2045                                                   &do_forward);
2046   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
2047               "New inbound delay for peer `%s' is %llu ms\n",
2048               GNUNET_i2s (&n->id),
2049               delay.rel_value_us / 1000);
2050   papi->update_inbound_delay (papi->cls,
2051                               &n->id,
2052                               n->primary_address.session,
2053                               delay);
2054 }
2055
2056
2057 /**
2058  * Create a fresh entry in the neighbour map for the given peer
2059  *
2060  * @param peer peer to create an entry for
2061  * @return new neighbour map entry
2062  */
2063 static struct NeighbourMapEntry *
2064 setup_neighbour (const struct GNUNET_PeerIdentity *peer)
2065 {
2066   struct NeighbourMapEntry *n;
2067
2068   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
2069               "Creating new neighbour entry for `%s'\n",
2070               GNUNET_i2s (peer));
2071   n = GNUNET_new (struct NeighbourMapEntry);
2072   n->id = *peer;
2073   n->ack_state = ACK_UNDEFINED;
2074   n->last_util_transmission = GNUNET_TIME_absolute_get();
2075   GNUNET_BANDWIDTH_tracker_init (&n->in_tracker,
2076                                  &inbound_bw_tracker_update,
2077                                  n,
2078                                  GNUNET_CONSTANTS_DEFAULT_BW_IN_OUT,
2079                                  MAX_BANDWIDTH_CARRY_S);
2080   n->task = GNUNET_SCHEDULER_add_now (&master_task, n);
2081   set_state_and_timeout (n,
2082                          GNUNET_TRANSPORT_PS_NOT_CONNECTED,
2083                          GNUNET_TIME_UNIT_FOREVER_ABS);
2084   GNUNET_assert (GNUNET_OK ==
2085                  GNUNET_CONTAINER_multipeermap_put (neighbours,
2086                                                     &n->id, n,
2087                                                     GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_ONLY));
2088   n->suggest_handle = GNUNET_ATS_connectivity_suggest (GST_ats_connect,
2089                                                        peer);
2090
2091   return n;
2092 }
2093
2094
2095 /**
2096  * Entry in a DLL we use to keep track of pending blacklist checks.
2097  */
2098 struct BlacklistCheckSwitchContext
2099 {
2100   /**
2101    * DLL prev pointer.
2102    */
2103   struct BlacklistCheckSwitchContext *prev;
2104
2105   /**
2106    * DLL next pointer.
2107    */
2108   struct BlacklistCheckSwitchContext *next;
2109
2110   /**
2111    * Handle to the blacklist check we are performing.
2112    */
2113   struct GST_BlacklistCheck *blc;
2114
2115   /**
2116    * Address we are asking the blacklist subsystem about.
2117    */
2118   struct GNUNET_HELLO_Address *address;
2119
2120   /**
2121    * Session we should use in conjunction with @e address, can be NULL.
2122    */
2123   struct Session *session;
2124
2125   /**
2126    * Inbound bandwidth that was assigned to @e address.
2127    */
2128   struct GNUNET_BANDWIDTH_Value32NBO bandwidth_in;
2129
2130   /**
2131    * Outbound bandwidth that was assigned to @e address.
2132    */
2133   struct GNUNET_BANDWIDTH_Value32NBO bandwidth_out;
2134 };
2135
2136
2137 /**
2138  * Black list check result for try_connect call
2139  * If connection to the peer is allowed request adddress and
2140  *
2141  * @param cls blc_ctx bl context
2142  * @param peer the peer
2143  * @param result the result
2144  */
2145 static void
2146 try_connect_bl_check_cont (void *cls,
2147                            const struct GNUNET_PeerIdentity *peer,
2148                            int result)
2149 {
2150   struct BlacklistCheckSwitchContext *blc_ctx = cls;
2151   struct NeighbourMapEntry *n;
2152
2153   GNUNET_CONTAINER_DLL_remove (pending_bc_head,
2154                                pending_bc_tail,
2155                                blc_ctx);
2156   GNUNET_free (blc_ctx);
2157   if (GNUNET_OK != result)
2158   {
2159     GNUNET_log (GNUNET_ERROR_TYPE_INFO,
2160                 _("Blacklisting disapproved to connect to peer `%s'\n"),
2161                 GNUNET_i2s (peer));
2162     return;
2163   }
2164
2165   /* Setup a new neighbour */
2166   if (NULL != lookup_neighbour(peer))
2167     return; /* The neighbor was created in the meantime while waited for BL clients */
2168
2169   n = setup_neighbour (peer);
2170
2171   /* Request address suggestions for this peer */
2172   set_state_and_timeout (n,
2173                          GNUNET_TRANSPORT_PS_INIT_ATS,
2174                          GNUNET_TIME_relative_to_absolute (ATS_RESPONSE_TIMEOUT));
2175 }
2176
2177
2178 /**
2179  * Try to create a connection to the given target (eventually).
2180  *
2181  * @param target peer to try to connect to
2182  */
2183 void
2184 GST_neighbours_try_connect (const struct GNUNET_PeerIdentity *target)
2185 {
2186   struct NeighbourMapEntry *n;
2187   struct GST_BlacklistCheck *blc;
2188   struct BlacklistCheckSwitchContext *blc_ctx;
2189
2190   if (NULL == neighbours)
2191   {
2192     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
2193                 "Asked to connect to peer `%s' during shutdown\n",
2194                 GNUNET_i2s (target));
2195     return; /* during shutdown, do nothing */
2196   }
2197   n = lookup_neighbour (target);
2198   GNUNET_log (GNUNET_ERROR_TYPE_INFO,
2199               "Asked to connect to peer `%s' (state: %s)\n",
2200               GNUNET_i2s (target),
2201               (NULL != n) ? GNUNET_TRANSPORT_ps2s(n->state) : "NEW PEER");
2202   if (NULL != n)
2203   {
2204     switch (n->state)
2205     {
2206     case GNUNET_TRANSPORT_PS_NOT_CONNECTED:
2207       /* this should not be possible */
2208       GNUNET_break (0);
2209       free_neighbour (n);
2210       break;
2211     case GNUNET_TRANSPORT_PS_INIT_ATS:
2212     case GNUNET_TRANSPORT_PS_SYN_SENT:
2213     case GNUNET_TRANSPORT_PS_SYN_RECV_ATS:
2214     case GNUNET_TRANSPORT_PS_SYN_RECV_ACK:
2215       GNUNET_log (GNUNET_ERROR_TYPE_INFO,
2216                   "Ignoring request to try to connect to `%s', already trying!\n",
2217                   GNUNET_i2s (target));
2218       return; /* already trying */
2219     case GNUNET_TRANSPORT_PS_CONNECTED:
2220     case GNUNET_TRANSPORT_PS_RECONNECT_ATS:
2221     case GNUNET_TRANSPORT_PS_RECONNECT_SENT:
2222     case GNUNET_TRANSPORT_PS_SWITCH_SYN_SENT:
2223       GNUNET_log (GNUNET_ERROR_TYPE_INFO,
2224                   "Ignoring request to try to connect, already connected to `%s'!\n",
2225                   GNUNET_i2s (target));
2226       return; /* already connected */
2227     case GNUNET_TRANSPORT_PS_DISCONNECT:
2228       /* get rid of remains, ready to re-try immediately */
2229       free_neighbour (n);
2230       break;
2231     case GNUNET_TRANSPORT_PS_DISCONNECT_FINISHED:
2232       /* should not be possible */
2233       GNUNET_assert (0);
2234       return;
2235     default:
2236       GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
2237                   "Unhandled state `%s'\n",
2238                   GNUNET_TRANSPORT_ps2s (n->state));
2239       GNUNET_break (0);
2240       free_neighbour (n);
2241       break;
2242     }
2243   }
2244
2245   /* Do blacklist check if connecting to this peer is allowed */
2246   blc_ctx = GNUNET_new (struct BlacklistCheckSwitchContext);
2247   GNUNET_CONTAINER_DLL_insert (pending_bc_head,
2248                                pending_bc_tail,
2249                                blc_ctx);
2250
2251   if (NULL !=
2252       (blc = GST_blacklist_test_allowed (target,
2253                                          NULL,
2254                                          &try_connect_bl_check_cont,
2255                                          blc_ctx)))
2256   {
2257     blc_ctx->blc = blc;
2258   }
2259 }
2260
2261
2262 /**
2263  * We received a 'SYN' message from the other peer.
2264  * Consider switching to it.
2265  *
2266  * @param message possibly a 'struct TransportSynMessage' (check format)
2267  * @param peer identity of the peer to switch the address for
2268  * @return #GNUNET_OK if the message was fine, #GNUNET_SYSERR on serious error
2269  */
2270 int
2271 GST_neighbours_handle_session_syn (const struct GNUNET_MessageHeader *message,
2272                                    const struct GNUNET_PeerIdentity *peer)
2273 {
2274   const struct TransportSynMessage *scm;
2275   struct NeighbourMapEntry *n;
2276   struct GNUNET_TIME_Absolute ts;
2277
2278   if (ntohs (message->size) != sizeof (struct TransportSynMessage))
2279   {
2280     GNUNET_break_op (0);
2281     return GNUNET_SYSERR;
2282   }
2283   GNUNET_STATISTICS_update (GST_stats,
2284                             gettext_noop
2285                             ("# SYN messages received"),
2286                             1, GNUNET_NO);
2287   if (NULL == neighbours)
2288   {
2289     GNUNET_log (GNUNET_ERROR_TYPE_INFO,
2290                 _("SYN request from peer `%s' ignored due impending shutdown\n"),
2291                 GNUNET_i2s (peer));
2292     return GNUNET_OK; /* we're shutting down */
2293   }
2294   scm = (const struct TransportSynMessage *) message;
2295   GNUNET_break_op (0 == ntohl (scm->reserved));
2296   ts = GNUNET_TIME_absolute_ntoh (scm->timestamp);
2297   n = lookup_neighbour (peer);
2298   if (NULL == n)
2299   {
2300     /* This is a new neighbour and set to not connected */
2301     n = setup_neighbour (peer);
2302   }
2303
2304   /* Remember this SYN message in neighbour */
2305   n->ack_state = ACK_SEND_SYN_ACK;
2306   n->connect_ack_timestamp = ts;
2307
2308   GNUNET_log (GNUNET_ERROR_TYPE_INFO,
2309               "Received SYN for peer `%s' in state %s/%s\n",
2310               GNUNET_i2s (peer),
2311               GNUNET_TRANSPORT_ps2s (n->state),
2312               print_ack_state (n->ack_state));
2313
2314   switch (n->state)
2315   {
2316   case GNUNET_TRANSPORT_PS_NOT_CONNECTED:
2317     /* Request an address from ATS to send SYN_ACK to this peer */
2318     set_state_and_timeout (n,
2319                            GNUNET_TRANSPORT_PS_SYN_RECV_ATS,
2320                            GNUNET_TIME_relative_to_absolute (ATS_RESPONSE_TIMEOUT));
2321     break;
2322   case GNUNET_TRANSPORT_PS_INIT_ATS:
2323     /* SYN message takes priority over us asking ATS for address:
2324      * Wait for ATS to suggest an address and send SYN_ACK */
2325     set_state_and_timeout (n,
2326                            GNUNET_TRANSPORT_PS_SYN_RECV_ATS,
2327                            GNUNET_TIME_relative_to_absolute (ATS_RESPONSE_TIMEOUT));
2328     break;
2329   case GNUNET_TRANSPORT_PS_SYN_RECV_ATS:
2330     /* We already wait for an address to send an SYN_ACK */
2331     break;
2332   case GNUNET_TRANSPORT_PS_SYN_SENT:
2333   case GNUNET_TRANSPORT_PS_SYN_RECV_ACK:
2334     /* Send ACK immediately */
2335     n->ack_state = ACK_SEND_ACK;
2336     send_syn_ack_message (&n->primary_address,
2337                           ts);
2338     break;
2339   case GNUNET_TRANSPORT_PS_CONNECTED:
2340     /* we are already connected and can thus send the ACK immediately */
2341     GNUNET_assert (NULL != n->primary_address.address);
2342     GNUNET_assert (NULL != n->primary_address.session);
2343     n->ack_state = ACK_SEND_ACK;
2344     send_syn_ack_message (&n->primary_address,
2345                           ts);
2346     break;
2347   case GNUNET_TRANSPORT_PS_RECONNECT_ATS:
2348     /* We wait for ATS address suggestion */
2349     break;
2350   case GNUNET_TRANSPORT_PS_RECONNECT_SENT:
2351     /* We received a SYN message while waiting for a SYN_ACK in fast
2352      * reconnect. Send SYN_ACK immediately */
2353     n->ack_state = ACK_SEND_ACK;
2354     send_syn_ack_message (&n->primary_address,
2355                           n->connect_ack_timestamp);
2356     break;
2357   case GNUNET_TRANSPORT_PS_SWITCH_SYN_SENT:
2358     /* We are already connected and can thus send the ACK immediately;
2359        still, it can never hurt to have an alternative address, so also
2360        tell ATS  about it */
2361     GNUNET_assert (NULL != n->primary_address.address);
2362     GNUNET_assert (NULL != n->primary_address.session);
2363     n->ack_state = ACK_SEND_ACK;
2364     send_syn_ack_message (&n->primary_address,
2365                           ts);
2366     break;
2367   case GNUNET_TRANSPORT_PS_DISCONNECT:
2368     /* Get rid of remains and re-try */
2369     free_neighbour (n);
2370     n = setup_neighbour (peer);
2371     /* Remember the SYN time stamp for ACK message */
2372     n->ack_state = ACK_SEND_SYN_ACK;
2373     n->connect_ack_timestamp = ts;
2374     /* Request an address for the peer */
2375     set_state_and_timeout (n,
2376                            GNUNET_TRANSPORT_PS_SYN_RECV_ATS,
2377                            GNUNET_TIME_relative_to_absolute (ATS_RESPONSE_TIMEOUT));
2378     break;
2379   case GNUNET_TRANSPORT_PS_DISCONNECT_FINISHED:
2380     /* should not be possible */
2381     GNUNET_assert (0);
2382     break;
2383   default:
2384     GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
2385                 "Unhandled state `%s'\n",
2386                 GNUNET_TRANSPORT_ps2s (n->state));
2387     GNUNET_break (0);
2388     return GNUNET_SYSERR;
2389   }
2390   return GNUNET_OK;
2391 }
2392
2393
2394 /**
2395  * Check if the given @a address is the same that we are already
2396  * using for the respective neighbour. If so, update the bandwidth
2397  * assignment and possibly the session and return #GNUNET_OK.
2398  * If the new address is different from what the neighbour is
2399  * using right now, return #GNUNET_NO.
2400  *
2401  * @param address address of the other peer,
2402  * @param session session to use or NULL if transport should initiate a session
2403  * @param bandwidth_in inbound quota to be used when connection is up,
2404  *      0 to disconnect from peer
2405  * @param bandwidth_out outbound quota to be used when connection is up,
2406  *      0 to disconnect from peer
2407  * @return #GNUNET_OK if we were able to just update the bandwidth and session,
2408  *         #GNUNET_NO if more extensive changes are required (address changed)
2409  */
2410 static int
2411 try_run_fast_ats_update (const struct GNUNET_HELLO_Address *address,
2412                          struct Session *session,
2413                          struct GNUNET_BANDWIDTH_Value32NBO bandwidth_in,
2414                          struct GNUNET_BANDWIDTH_Value32NBO bandwidth_out)
2415 {
2416   struct NeighbourMapEntry *n;
2417
2418   n = lookup_neighbour (&address->peer);
2419   if ( (NULL == n) ||
2420        (NULL == n->primary_address.address) ||
2421        (0 != GNUNET_HELLO_address_cmp (address,
2422                                        n->primary_address.address)) )
2423     return GNUNET_NO;
2424   /* We are not really switching addresses, but merely adjusting
2425      session and/or bandwidth, can do fast ATS update! */
2426   if (session != n->primary_address.session)
2427   {
2428     /* switch to a different session, but keeping same address; could
2429        happen if there is a 2nd inbound connection */
2430     n->primary_address.session = session;
2431   }
2432   n->primary_address.bandwidth_in = bandwidth_in;
2433   n->primary_address.bandwidth_out = bandwidth_out;
2434   GST_neighbours_set_incoming_quota (&address->peer,
2435                                      bandwidth_in);
2436   send_outbound_quota (&address->peer,
2437                        bandwidth_out);
2438   return GNUNET_OK;
2439 }
2440
2441
2442 /**
2443  * We've been asked to switch addresses, and just now got the result
2444  * from the blacklist check to see if this is allowed.
2445  *
2446  * @param cls the `struct BlacklistCheckSwitchContext` with
2447  *        the information about the future address
2448  * @param peer the peer we may switch addresses on
2449  * @param result #GNUNET_NO if we are not allowed to use the new
2450  *        address
2451  */
2452 static void
2453 switch_address_bl_check_cont (void *cls,
2454                               const struct GNUNET_PeerIdentity *peer,
2455                               int result)
2456 {
2457   struct BlacklistCheckSwitchContext *blc_ctx = cls;
2458   struct GNUNET_TRANSPORT_PluginFunctions *papi;
2459   struct NeighbourMapEntry *n;
2460
2461   if (result == GNUNET_NO)
2462   {
2463     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
2464                 "Blacklist denied to switch to suggested address `%s' session %p for peer `%s'\n",
2465                 GST_plugins_a2s (blc_ctx->address),
2466                 blc_ctx->session,
2467                 GNUNET_i2s (&blc_ctx->address->peer));
2468     GNUNET_STATISTICS_update (GST_stats,
2469                               "# ATS suggestions ignored (blacklist denied)",
2470                               1,
2471                               GNUNET_NO);
2472     /* FIXME: tell plugin to force killing session here and now
2473        (note: _proper_ plugin API for this does not yet exist) */
2474     GST_ats_block_address (blc_ctx->address,
2475                            blc_ctx->session);
2476     goto cleanup;
2477   }
2478
2479   papi = GST_plugins_find (blc_ctx->address->transport_name);
2480   GNUNET_assert (NULL != papi);
2481
2482   if (NULL == blc_ctx->session)
2483   {
2484     /* need to create a session, ATS only gave us an address */
2485     blc_ctx->session = papi->get_session (papi->cls,
2486                                           blc_ctx->address);
2487     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
2488                 "Obtained new session for peer `%s' and  address '%s': %p\n",
2489                 GNUNET_i2s (&blc_ctx->address->peer),
2490                 GST_plugins_a2s (blc_ctx->address),
2491                 blc_ctx->session);
2492     if (NULL != blc_ctx->session)
2493       GST_ats_new_session (blc_ctx->address,
2494                            blc_ctx->session);
2495   }
2496   if (NULL == blc_ctx->session)
2497   {
2498     /* session creation failed, bad!, fail! */
2499     GNUNET_STATISTICS_update (GST_stats,
2500                               "# ATS suggestions ignored (failed to create session)",
2501                               1,
2502                               GNUNET_NO);
2503     /* No session could be obtained, remove blacklist check and clean up */
2504     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
2505                 "Failed to obtain new session for peer `%s' and address '%s'\n",
2506                 GNUNET_i2s (&blc_ctx->address->peer),
2507                 GST_plugins_a2s (blc_ctx->address));
2508     GST_ats_block_address (blc_ctx->address,
2509                            blc_ctx->session);
2510     goto cleanup;
2511   }
2512
2513   /* We did this check already before going into blacklist, but
2514      it is theoretically possible that the situation changed in
2515      the meantime, hence we check again here */
2516   if (GNUNET_OK ==
2517       try_run_fast_ats_update (blc_ctx->address,
2518                                blc_ctx->session,
2519                                blc_ctx->bandwidth_in,
2520                                blc_ctx->bandwidth_out))
2521     goto cleanup; /* was just a minor update, we're done */
2522
2523   /* check if we also need to setup the neighbour entry */
2524   if (NULL == (n = lookup_neighbour (peer)))
2525   {
2526     n = setup_neighbour (peer);
2527     n->state = GNUNET_TRANSPORT_PS_INIT_ATS;
2528   }
2529
2530   GNUNET_log (GNUNET_ERROR_TYPE_INFO,
2531               "Peer `%s' switches to address `%s'\n",
2532               GNUNET_i2s (&blc_ctx->address->peer),
2533               GST_plugins_a2s (blc_ctx->address));
2534
2535   switch (n->state)
2536   {
2537   case GNUNET_TRANSPORT_PS_NOT_CONNECTED:
2538     GNUNET_break (0);
2539     GST_ats_block_address (blc_ctx->address,
2540                            blc_ctx->session);
2541     free_neighbour (n);
2542     return;
2543   case GNUNET_TRANSPORT_PS_INIT_ATS:
2544     /* We requested an address and ATS suggests one:
2545      * set primary address and send SYN message*/
2546     set_primary_address (n,
2547                          blc_ctx->address,
2548                          blc_ctx->session,
2549                          blc_ctx->bandwidth_in,
2550                          blc_ctx->bandwidth_out);
2551     if (ACK_SEND_SYN_ACK == n->ack_state)
2552     {
2553       /* Send pending SYN_ACK message */
2554       n->ack_state = ACK_SEND_ACK;
2555       send_syn_ack_message (&n->primary_address,
2556                             n->connect_ack_timestamp);
2557     }
2558     set_state_and_timeout (n,
2559                            GNUNET_TRANSPORT_PS_SYN_SENT,
2560                            GNUNET_TIME_relative_to_absolute (SETUP_CONNECTION_TIMEOUT));
2561     send_syn (&n->primary_address);
2562     break;
2563   case GNUNET_TRANSPORT_PS_SYN_SENT:
2564     /* ATS suggested a new address while waiting for an SYN_ACK:
2565      * Switch and send new SYN */
2566     /* ATS suggests a different address, switch again */
2567     set_primary_address (n,
2568                          blc_ctx->address,
2569                          blc_ctx->session,
2570                          blc_ctx->bandwidth_in,
2571                          blc_ctx->bandwidth_out);
2572     if (ACK_SEND_SYN_ACK == n->ack_state)
2573     {
2574       /* Send pending SYN_ACK message */
2575       n->ack_state = ACK_SEND_ACK;
2576       send_syn_ack_message (&n->primary_address,
2577                             n->connect_ack_timestamp);
2578     }
2579     set_state_and_timeout (n,
2580                            GNUNET_TRANSPORT_PS_SYN_SENT,
2581                            GNUNET_TIME_relative_to_absolute (SETUP_CONNECTION_TIMEOUT));
2582     send_syn (&n->primary_address);
2583     break;
2584   case GNUNET_TRANSPORT_PS_SYN_RECV_ATS:
2585     /* We requested an address and ATS suggests one:
2586      * set primary address and send SYN_ACK message*/
2587     set_primary_address (n,
2588                          blc_ctx->address,
2589                          blc_ctx->session,
2590                          blc_ctx->bandwidth_in,
2591                          blc_ctx->bandwidth_out);
2592     /* Send an ACK message as a response to the SYN msg */
2593     set_state_and_timeout (n,
2594                            GNUNET_TRANSPORT_PS_SYN_RECV_ACK,
2595                            GNUNET_TIME_relative_to_absolute (SETUP_CONNECTION_TIMEOUT));
2596     send_syn_ack_message (&n->primary_address,
2597                           n->connect_ack_timestamp);
2598     if ( (ACK_SEND_SYN_ACK == n->ack_state) ||
2599          (ACK_UNDEFINED == n->ack_state) )
2600       n->ack_state = ACK_SEND_ACK;
2601     break;
2602   case GNUNET_TRANSPORT_PS_SYN_RECV_ACK:
2603     /* ATS asks us to switch while we were trying to connect; switch to new
2604        address and check blacklist again */
2605     if ( (ACK_SEND_SYN_ACK == n->ack_state) )
2606     {
2607       n->ack_state = ACK_SEND_ACK;
2608       send_syn_ack_message (&n->primary_address,
2609                             n->connect_ack_timestamp);
2610     }
2611     set_primary_address (n,
2612                          blc_ctx->address,
2613                          blc_ctx->session,
2614                          blc_ctx->bandwidth_in,
2615                          blc_ctx->bandwidth_out);
2616     set_state_and_timeout (n,
2617                            GNUNET_TRANSPORT_PS_SYN_RECV_ACK,
2618                            GNUNET_TIME_relative_to_absolute (SETUP_CONNECTION_TIMEOUT));
2619     break;
2620   case GNUNET_TRANSPORT_PS_CONNECTED:
2621     GNUNET_assert (NULL != n->primary_address.address);
2622     GNUNET_assert (NULL != n->primary_address.session);
2623     GNUNET_break (n->primary_address.session != blc_ctx->session);
2624     /* ATS asks us to switch a life connection; see if we can get
2625        a SYN_ACK on it before we actually do this! */
2626     set_alternative_address (n,
2627                              blc_ctx->address,
2628                              blc_ctx->session,
2629                              blc_ctx->bandwidth_in,
2630                              blc_ctx->bandwidth_out);
2631     set_state_and_timeout (n,
2632                            GNUNET_TRANSPORT_PS_SWITCH_SYN_SENT,
2633                            GNUNET_TIME_relative_to_absolute (SETUP_CONNECTION_TIMEOUT));
2634     GNUNET_STATISTICS_update (GST_stats,
2635                               gettext_noop ("# Attempts to switch addresses"),
2636                               1,
2637                               GNUNET_NO);
2638     send_syn (&n->alternative_address);
2639     break;
2640   case GNUNET_TRANSPORT_PS_RECONNECT_ATS:
2641     set_primary_address (n,
2642                          blc_ctx->address,
2643                          blc_ctx->session,
2644                          blc_ctx->bandwidth_in,
2645                          blc_ctx->bandwidth_out);
2646     if (ACK_SEND_SYN_ACK == n->ack_state)
2647     {
2648       /* Send pending SYN_ACK message */
2649       n->ack_state = ACK_SEND_ACK;
2650       send_syn_ack_message (&n->primary_address,
2651                             n->connect_ack_timestamp);
2652     }
2653     set_state_and_timeout (n,
2654                            GNUNET_TRANSPORT_PS_RECONNECT_SENT,
2655                            GNUNET_TIME_relative_to_absolute (FAST_RECONNECT_TIMEOUT));
2656     send_syn (&n->primary_address);
2657     break;
2658   case GNUNET_TRANSPORT_PS_RECONNECT_SENT:
2659     /* ATS asks us to switch while we were trying to reconnect; switch to new
2660        address and send SYN again */
2661     set_primary_address (n,
2662                          blc_ctx->address,
2663                          blc_ctx->session,
2664                          blc_ctx->bandwidth_in,
2665                          blc_ctx->bandwidth_out);
2666     set_state_and_timeout (n,
2667                            GNUNET_TRANSPORT_PS_RECONNECT_SENT,
2668                            GNUNET_TIME_relative_to_absolute (FAST_RECONNECT_TIMEOUT));
2669     send_syn (&n->primary_address);
2670     break;
2671   case GNUNET_TRANSPORT_PS_SWITCH_SYN_SENT:
2672     if ( (0 == GNUNET_HELLO_address_cmp (n->primary_address.address,
2673                                          blc_ctx->address)) &&
2674          (n->primary_address.session == blc_ctx->session) )
2675     {
2676       /* ATS switches back to still-active session */
2677       GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
2678                   "ATS double-switched, cleaning up alternative address\n");
2679       free_address (&n->alternative_address);
2680       set_state_and_timeout (n,
2681                              GNUNET_TRANSPORT_PS_CONNECTED,
2682                              n->timeout);
2683       break;
2684     }
2685     /* ATS asks us to switch a life connection, send */
2686     set_alternative_address (n,
2687                              blc_ctx->address,
2688                              blc_ctx->session,
2689                              blc_ctx->bandwidth_in,
2690                              blc_ctx->bandwidth_out);
2691     set_state_and_timeout (n,
2692                            GNUNET_TRANSPORT_PS_SWITCH_SYN_SENT,
2693                            GNUNET_TIME_relative_to_absolute (SETUP_CONNECTION_TIMEOUT));
2694     send_syn (&n->alternative_address);
2695     break;
2696   case GNUNET_TRANSPORT_PS_DISCONNECT:
2697     /* not going to switch addresses while disconnecting */
2698     GNUNET_STATISTICS_update (GST_stats,
2699                               "# ATS suggestion ignored (disconnecting)",
2700                               1,
2701                               GNUNET_NO);
2702     return;
2703   case GNUNET_TRANSPORT_PS_DISCONNECT_FINISHED:
2704     GNUNET_assert (0);
2705     break;
2706   default:
2707     GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
2708                 "Unhandled state `%s'\n",
2709                 GNUNET_TRANSPORT_ps2s (n->state));
2710     GNUNET_break (0);
2711     break;
2712   }
2713  cleanup:
2714   GNUNET_CONTAINER_DLL_remove (pending_bc_head,
2715                                pending_bc_tail,
2716                                blc_ctx);
2717   GNUNET_HELLO_address_free (blc_ctx->address);
2718   GNUNET_free (blc_ctx);
2719 }
2720
2721
2722 /**
2723  * For the given peer, switch to this address.
2724  *
2725  * Before accepting this addresses and actively using it, a blacklist check
2726  * is performed.
2727  *
2728  * If any check fails or the suggestion can somehow not be followed, we
2729  * MUST call #GST_ats_block_address() to tell ATS that the suggestion
2730  * could not be satisfied and force ATS to do something else.
2731  *
2732  * @param address address of the other peer,
2733  * @param session session to use or NULL if transport should initiate a session
2734  * @param bandwidth_in inbound quota to be used when connection is up,
2735  *      0 to disconnect from peer
2736  * @param bandwidth_out outbound quota to be used when connection is up,
2737  *      0 to disconnect from peer
2738  */
2739 void
2740 GST_neighbours_switch_to_address (const struct GNUNET_HELLO_Address *address,
2741                                   struct Session *session,
2742                                   struct GNUNET_BANDWIDTH_Value32NBO bandwidth_in,
2743                                   struct GNUNET_BANDWIDTH_Value32NBO bandwidth_out)
2744 {
2745   struct GST_BlacklistCheck *blc;
2746   struct BlacklistCheckSwitchContext *blc_ctx;
2747
2748   GNUNET_assert (NULL != address->transport_name);
2749   if (GNUNET_OK ==
2750       try_run_fast_ats_update (address,
2751                                session,
2752                                bandwidth_in,
2753                                bandwidth_out))
2754     return;
2755
2756   /* Check if plugin is available */
2757   if (NULL == (GST_plugins_find (address->transport_name)))
2758   {
2759     /* we don't have the plugin for this address */
2760     GNUNET_break (0);
2761     GST_ats_block_address (address,
2762                            session);
2763     return;
2764   }
2765   if ((NULL == session) &&
2766       (GNUNET_HELLO_address_check_option (address,
2767                                           GNUNET_HELLO_ADDRESS_INFO_INBOUND)))
2768   {
2769     /* This is a inbound address and we do not have a session to use! */
2770     GNUNET_break (0);
2771     GST_ats_block_address (address,
2772                            session);
2773     return;
2774   }
2775
2776   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
2777               "ATS suggests address '%s' for peer `%s' at %u/%u speed\n",
2778               GST_plugins_a2s (address),
2779               GNUNET_i2s (&address->peer),
2780               (unsigned int) ntohl (bandwidth_in.value__),
2781               (unsigned int) ntohl (bandwidth_out.value__));
2782
2783   /* Perform blacklist check */
2784   blc_ctx = GNUNET_new (struct BlacklistCheckSwitchContext);
2785   blc_ctx->address = GNUNET_HELLO_address_copy (address);
2786   blc_ctx->session = session;
2787   blc_ctx->bandwidth_in = bandwidth_in;
2788   blc_ctx->bandwidth_out = bandwidth_out;
2789   GNUNET_CONTAINER_DLL_insert (pending_bc_head,
2790                                pending_bc_tail,
2791                                blc_ctx);
2792   if (NULL != (blc = GST_blacklist_test_allowed (&address->peer,
2793                                                  address->transport_name,
2794                                                  &switch_address_bl_check_cont,
2795                                                  blc_ctx)))
2796   {
2797     blc_ctx->blc = blc;
2798   }
2799 }
2800
2801
2802 /**
2803  * Function called to send network utilization data to ATS for
2804  * each active connection.
2805  *
2806  * @param cls NULL
2807  * @param key peer we send utilization data for
2808  * @param value the `struct NeighbourMapEntry *` with data to send
2809  * @return #GNUNET_OK (continue to iterate)
2810  */
2811 static int
2812 send_utilization_data (void *cls,
2813                        const struct GNUNET_PeerIdentity *key,
2814                        void *value)
2815 {
2816   struct NeighbourMapEntry *n = value;
2817   struct GNUNET_ATS_Information atsi[4];
2818   uint32_t bps_in;
2819   uint32_t bps_out;
2820   struct GNUNET_TIME_Relative delta;
2821
2822   if ( (GNUNET_YES != test_connected (n)) ||
2823        (NULL == n->primary_address.address) )
2824     return GNUNET_OK;
2825   delta = GNUNET_TIME_absolute_get_difference (n->last_util_transmission,
2826                                                GNUNET_TIME_absolute_get ());
2827   bps_in = 0;
2828   if ((0 != n->util_total_bytes_recv) && (0 != delta.rel_value_us))
2829     bps_in =  (1000LL * 1000LL *  n->util_total_bytes_recv) / (delta.rel_value_us);
2830   bps_out = 0;
2831   if ((0 != n->util_total_bytes_sent) && (0 != delta.rel_value_us))
2832     bps_out = (1000LL * 1000LL * n->util_total_bytes_sent) / delta.rel_value_us;
2833
2834   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
2835               "`%s' total: received %u Bytes/s, sent %u Bytes/s\n",
2836               GNUNET_i2s (key),
2837               bps_in,
2838               bps_out);
2839   atsi[0].type = htonl (GNUNET_ATS_UTILIZATION_OUT);
2840   atsi[0].value = htonl (bps_out);
2841   atsi[1].type = htonl (GNUNET_ATS_UTILIZATION_IN);
2842   atsi[1].value = htonl (bps_in);
2843   GST_ats_update_metrics (n->primary_address.address,
2844                           n->primary_address.session,
2845                           atsi, 2);
2846   n->util_total_bytes_recv = 0;
2847   n->util_total_bytes_sent = 0;
2848   n->last_util_transmission = GNUNET_TIME_absolute_get ();
2849   return GNUNET_OK;
2850 }
2851
2852
2853 /**
2854  * Task transmitting utilization in a regular interval
2855  *
2856  * @param cls the 'struct NeighbourMapEntry' for which we are running
2857  * @param tc scheduler context (unused)
2858  */
2859 static void
2860 utilization_transmission (void *cls,
2861                           const struct GNUNET_SCHEDULER_TaskContext *tc)
2862 {
2863   util_transmission_tk = NULL;
2864   GNUNET_CONTAINER_multipeermap_iterate (neighbours,
2865                                          &send_utilization_data,
2866                                          NULL);
2867   util_transmission_tk
2868     = GNUNET_SCHEDULER_add_delayed (UTIL_TRANSMISSION_INTERVAL,
2869                                     &utilization_transmission,
2870                                     NULL);
2871 }
2872
2873
2874 /**
2875  * Track information about data we received from the
2876  * given address (used to notify ATS about our utilization
2877  * of allocated resources).
2878  *
2879  * @param address the address we got data from
2880  * @param message the message we received (really only the size is used)
2881  */
2882 void
2883 GST_neighbours_notify_data_recv (const struct GNUNET_HELLO_Address *address,
2884                                  const struct GNUNET_MessageHeader *message)
2885 {
2886   struct NeighbourMapEntry *n;
2887
2888   n = lookup_neighbour (&address->peer);
2889   if (NULL == n)
2890     return;
2891   n->util_total_bytes_recv += ntohs (message->size);
2892 }
2893
2894
2895 /**
2896  * Track information about data we transmitted using the given @a
2897  * address and @a session (used to notify ATS about our utilization of
2898  * allocated resources).
2899  *
2900  * @param address the address we transmitted data to
2901  * @param session session we used to transmit data
2902  * @param message the message we sent (really only the size is used)
2903  */
2904 void
2905 GST_neighbours_notify_data_sent (const struct GNUNET_HELLO_Address *address,
2906                                  struct Session *session,
2907                                  size_t size)
2908 {
2909   struct NeighbourMapEntry *n;
2910
2911   n = lookup_neighbour (&address->peer);
2912   if (NULL == n)
2913       return;
2914   if (n->primary_address.session != session)
2915     return;
2916   n->util_total_bytes_sent += size;
2917 }
2918
2919
2920 /**
2921  * Master task run for every neighbour.  Performs all of the time-related
2922  * activities (keep alive, send next message, disconnect if idle, finish
2923  * clean up after disconnect).
2924  *
2925  * @param cls the 'struct NeighbourMapEntry' for which we are running
2926  * @param tc scheduler context (unused)
2927  */
2928 static void
2929 master_task (void *cls,
2930              const struct GNUNET_SCHEDULER_TaskContext *tc)
2931 {
2932   struct NeighbourMapEntry *n = cls;
2933   struct GNUNET_TIME_Relative delay;
2934
2935   n->task = NULL;
2936   delay = GNUNET_TIME_absolute_get_remaining (n->timeout);
2937   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
2938               "Master task runs for neighbour `%s' in state %s with timeout in %s\n",
2939               GNUNET_i2s (&n->id),
2940               GNUNET_TRANSPORT_ps2s(n->state),
2941               GNUNET_STRINGS_relative_time_to_string (delay,
2942                                                       GNUNET_YES));
2943   switch (n->state)
2944   {
2945   case GNUNET_TRANSPORT_PS_NOT_CONNECTED:
2946     /* invalid state for master task, clean up */
2947     GNUNET_break (0);
2948     free_neighbour (n);
2949     return;
2950   case GNUNET_TRANSPORT_PS_INIT_ATS:
2951     if (0 == delay.rel_value_us)
2952     {
2953       GNUNET_log (GNUNET_ERROR_TYPE_INFO,
2954                   "Connection to `%s' timed out waiting for ATS to provide address\n",
2955                   GNUNET_i2s (&n->id));
2956       free_neighbour (n);
2957       return;
2958     }
2959     break;
2960   case GNUNET_TRANSPORT_PS_SYN_SENT:
2961     if (0 == delay.rel_value_us)
2962     {
2963       GNUNET_log (GNUNET_ERROR_TYPE_INFO,
2964                   "Connection to `%s' timed out waiting for other peer to send SYN_ACK\n",
2965                   GNUNET_i2s (&n->id));
2966       /* Remove address and request and additional one */
2967       unset_primary_address (n);
2968       set_state_and_timeout (n,
2969                              GNUNET_TRANSPORT_PS_INIT_ATS,
2970                              GNUNET_TIME_relative_to_absolute (ATS_RESPONSE_TIMEOUT));
2971       return;
2972     }
2973     break;
2974   case GNUNET_TRANSPORT_PS_SYN_RECV_ATS:
2975     if (0 == delay.rel_value_us)
2976     {
2977       GNUNET_log (GNUNET_ERROR_TYPE_INFO,
2978                   "Connection to `%s' timed out waiting ATS to provide address to use for SYN_ACK\n",
2979                   GNUNET_i2s (&n->id));
2980       free_neighbour (n);
2981       return;
2982     }
2983     break;
2984   case GNUNET_TRANSPORT_PS_SYN_RECV_ACK:
2985     if (0 == delay.rel_value_us)
2986     {
2987       GNUNET_log (GNUNET_ERROR_TYPE_INFO,
2988                   "Connection to `%s' timed out waiting for other peer to send ACK\n",
2989                   GNUNET_i2s (&n->id));
2990       disconnect_neighbour (n);
2991       return;
2992     }
2993     break;
2994   case GNUNET_TRANSPORT_PS_CONNECTED:
2995     if (0 == delay.rel_value_us)
2996     {
2997       GNUNET_log (GNUNET_ERROR_TYPE_INFO,
2998                   "Connection to `%s' timed out, missing KEEPALIVE_RESPONSEs\n",
2999                   GNUNET_i2s (&n->id));
3000       disconnect_neighbour (n);
3001       return;
3002     }
3003     try_transmission_to_peer (n);
3004     send_keepalive (n);
3005     break;
3006   case GNUNET_TRANSPORT_PS_RECONNECT_ATS:
3007     if (0 == delay.rel_value_us)
3008     {
3009       GNUNET_log (GNUNET_ERROR_TYPE_INFO,
3010                   "Connection to `%s' timed out, waiting for ATS replacement address\n",
3011                   GNUNET_i2s (&n->id));
3012       disconnect_neighbour (n);
3013       return;
3014     }
3015     break;
3016   case GNUNET_TRANSPORT_PS_RECONNECT_SENT:
3017     if (0 == delay.rel_value_us)
3018     {
3019       GNUNET_log (GNUNET_ERROR_TYPE_INFO,
3020                   "Connection to `%s' timed out, waiting for other peer to SYN_ACK replacement address\n",
3021                   GNUNET_i2s (&n->id));
3022       disconnect_neighbour (n);
3023       return;
3024     }
3025     break;
3026   case GNUNET_TRANSPORT_PS_SWITCH_SYN_SENT:
3027     if (0 == delay.rel_value_us)
3028     {
3029       GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
3030                   "Switch failed, cleaning up alternative address\n");
3031       free_address (&n->alternative_address);
3032       set_state_and_timeout (n,
3033                              GNUNET_TRANSPORT_PS_CONNECTED,
3034                              GNUNET_TIME_relative_to_absolute (SETUP_CONNECTION_TIMEOUT));
3035     }
3036     try_transmission_to_peer (n);
3037     send_keepalive (n);
3038     break;
3039   case GNUNET_TRANSPORT_PS_DISCONNECT:
3040     GNUNET_log (GNUNET_ERROR_TYPE_INFO,
3041                 "Cleaning up connection to `%s' after sending DISCONNECT\n",
3042                 GNUNET_i2s (&n->id));
3043     free_neighbour (n);
3044     return;
3045   case GNUNET_TRANSPORT_PS_DISCONNECT_FINISHED:
3046     /* how did we get here!? */
3047     GNUNET_assert (0);
3048     break;
3049   default:
3050     GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
3051                 "Unhandled state `%s'\n",
3052                 GNUNET_TRANSPORT_ps2s (n->state));
3053     GNUNET_break (0);
3054     break;
3055   }
3056   delay = GNUNET_TIME_absolute_get_remaining (n->timeout);
3057   if ( (GNUNET_TRANSPORT_PS_SWITCH_SYN_SENT == n->state) ||
3058        (GNUNET_TRANSPORT_PS_CONNECTED == n->state) )
3059   {
3060     /* if we are *now* in one of the two states, we're sending
3061        keep alive messages, so we need to consider the keepalive
3062        delay, not just the connection timeout */
3063     delay = GNUNET_TIME_relative_min (GNUNET_TIME_absolute_get_remaining (n->keep_alive_time),
3064                                       delay);
3065   }
3066   if (NULL == n->task)
3067     n->task = GNUNET_SCHEDULER_add_delayed (delay,
3068                                             &master_task,
3069                                             n);
3070 }
3071
3072
3073 /**
3074  * Send a ACK message to the neighbour to confirm that we
3075  * got his SYN_ACK.
3076  *
3077  * @param n neighbour to send the ACK to
3078  */
3079 static void
3080 send_session_ack_message (struct NeighbourMapEntry *n)
3081 {
3082   struct GNUNET_MessageHeader msg;
3083
3084   GNUNET_log (GNUNET_ERROR_TYPE_INFO,
3085               "Sending ACK message to peer `%s'\n",
3086               GNUNET_i2s (&n->id));
3087
3088   msg.size = htons (sizeof (struct GNUNET_MessageHeader));
3089   msg.type = htons (GNUNET_MESSAGE_TYPE_TRANSPORT_SESSION_ACK);
3090   (void) send_with_session (n,
3091                             &msg,
3092                             sizeof (struct GNUNET_MessageHeader),
3093                             UINT32_MAX,
3094                             GNUNET_TIME_UNIT_FOREVER_REL,
3095                             GNUNET_NO,
3096                             NULL, NULL);
3097 }
3098
3099
3100 /**
3101  * We received a 'SESSION_SYN_ACK' message from the other peer.
3102  * Consider switching to it.
3103  *
3104  * @param message possibly a `struct SessionConnectMessage` (check format)
3105  * @param peer identity of the peer to switch the address for
3106  * @param address address of the other peer, NULL if other peer
3107  *                       connected to us
3108  * @param session session to use (or NULL)
3109  * @return #GNUNET_OK if the message was fine, #GNUNET_SYSERR on serious error
3110  */
3111 int
3112 GST_neighbours_handle_session_syn_ack (const struct GNUNET_MessageHeader *message,
3113                                        const struct GNUNET_HELLO_Address *address,
3114                                        struct Session *session)
3115 {
3116   const struct TransportSynMessage *scm;
3117   struct GNUNET_TIME_Absolute ts;
3118   struct NeighbourMapEntry *n;
3119
3120   if (ntohs (message->size) != sizeof (struct TransportSynMessage))
3121   {
3122     GNUNET_break_op (0);
3123     return GNUNET_SYSERR;
3124   }
3125   GNUNET_STATISTICS_update (GST_stats,
3126                             gettext_noop
3127                             ("# SYN_ACK messages received"),
3128                             1, GNUNET_NO);
3129   scm = (const struct TransportSynMessage *) message;
3130   GNUNET_break_op (ntohl (scm->reserved) == 0);
3131   if (NULL == (n = lookup_neighbour (&address->peer)))
3132   {
3133     GNUNET_STATISTICS_update (GST_stats,
3134                               gettext_noop
3135                               ("# unexpected SYN_ACK messages (no peer)"),
3136                               1, GNUNET_NO);
3137     return GNUNET_SYSERR;
3138   }
3139   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
3140               "Received SYN_ACK message from peer `%s' in state %s/%s\n",
3141               GNUNET_i2s (&address->peer),
3142               GNUNET_TRANSPORT_ps2s (n->state),
3143               print_ack_state (n->ack_state));
3144   ts = GNUNET_TIME_absolute_ntoh (scm->timestamp);
3145   switch (n->state)
3146   {
3147   case GNUNET_TRANSPORT_PS_NOT_CONNECTED:
3148     GNUNET_break (0);
3149     free_neighbour (n);
3150     return GNUNET_SYSERR;
3151   case GNUNET_TRANSPORT_PS_INIT_ATS:
3152     GNUNET_STATISTICS_update (GST_stats,
3153                               gettext_noop ("# unexpected SYN_ACK messages (not ready)"),
3154                               1,
3155                               GNUNET_NO);
3156     break;
3157   case GNUNET_TRANSPORT_PS_SYN_SENT:
3158     if (ts.abs_value_us != n->primary_address.connect_timestamp.abs_value_us)
3159     {
3160       GNUNET_log (GNUNET_ERROR_TYPE_INFO,
3161                   "SYN_ACK ignored as the timestamp does not match our SYN request\n");
3162       return GNUNET_OK;
3163     }
3164     set_state_and_timeout (n,
3165                            GNUNET_TRANSPORT_PS_CONNECTED,
3166                            GNUNET_TIME_relative_to_absolute (GNUNET_CONSTANTS_IDLE_CONNECTION_TIMEOUT));
3167     set_primary_address (n,
3168                          n->primary_address.address,
3169                          n->primary_address.session,
3170                          n->primary_address.bandwidth_in,
3171                          n->primary_address.bandwidth_out);
3172     send_session_ack_message (n);
3173     break;
3174   case GNUNET_TRANSPORT_PS_SYN_RECV_ATS:
3175   case GNUNET_TRANSPORT_PS_SYN_RECV_ACK:
3176     GNUNET_STATISTICS_update (GST_stats,
3177                               gettext_noop ("# unexpected SYN_ACK messages (not ready)"),
3178                               1,
3179                               GNUNET_NO);
3180     break;
3181   case GNUNET_TRANSPORT_PS_CONNECTED:
3182     /* duplicate SYN_ACK, let's answer by duplicate ACK just in case */
3183     send_session_ack_message (n);
3184     break;
3185   case GNUNET_TRANSPORT_PS_RECONNECT_ATS:
3186     /* we didn't expect any SYN_ACK, as we are waiting for ATS
3187        to give us a new address... */
3188     GNUNET_STATISTICS_update (GST_stats,
3189                               gettext_noop ("# unexpected SYN_ACK messages (waiting on ATS)"),
3190                               1,
3191                               GNUNET_NO);
3192     break;
3193   case GNUNET_TRANSPORT_PS_RECONNECT_SENT:
3194     /* Reconnecting with new address address worked; go back to connected! */
3195     set_state_and_timeout (n,
3196                            GNUNET_TRANSPORT_PS_CONNECTED,
3197                            GNUNET_TIME_relative_to_absolute (GNUNET_CONSTANTS_IDLE_CONNECTION_TIMEOUT));
3198     send_session_ack_message (n);
3199     break;
3200   case GNUNET_TRANSPORT_PS_SWITCH_SYN_SENT:
3201     /* new address worked; adopt it and go back to connected! */
3202     set_state_and_timeout (n,
3203                            GNUNET_TRANSPORT_PS_CONNECTED,
3204                            GNUNET_TIME_relative_to_absolute (GNUNET_CONSTANTS_IDLE_CONNECTION_TIMEOUT));
3205     GNUNET_break (GNUNET_NO == n->alternative_address.ats_active);
3206
3207     /* Set primary addresses */
3208     set_primary_address (n,
3209                          n->alternative_address.address,
3210                          n->alternative_address.session,
3211                          n->alternative_address.bandwidth_in,
3212                          n->alternative_address.bandwidth_out);
3213     GNUNET_STATISTICS_update (GST_stats,
3214                               gettext_noop ("# Successful attempts to switch addresses"),
3215                               1,
3216                               GNUNET_NO);
3217
3218     GNUNET_HELLO_address_free (n->alternative_address.address);
3219     memset (&n->alternative_address,
3220             0,
3221             sizeof (n->alternative_address));
3222     send_session_ack_message (n);
3223     break;
3224   case GNUNET_TRANSPORT_PS_DISCONNECT:
3225     GNUNET_STATISTICS_update (GST_stats,
3226                               gettext_noop
3227                               ("# unexpected SYN_ACK messages (disconnecting)"),
3228                               1, GNUNET_NO);
3229     return GNUNET_SYSERR;
3230   case GNUNET_TRANSPORT_PS_DISCONNECT_FINISHED:
3231     GNUNET_assert (0);
3232     break;
3233   default:
3234     GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
3235                 "Unhandled state `%s'\n",
3236                 GNUNET_TRANSPORT_ps2s (n->state));
3237     GNUNET_break (0);
3238     return GNUNET_SYSERR;
3239   }
3240   return GNUNET_OK;
3241 }
3242
3243
3244 /**
3245  * A session was terminated. Take note; if needed, try to get
3246  * an alternative address from ATS.
3247  *
3248  * @param peer identity of the peer where the session died
3249  * @param session session that is gone
3250  * @return #GNUNET_YES if this was a session used, #GNUNET_NO if
3251  *        this session was not in use
3252  */
3253 int
3254 GST_neighbours_session_terminated (const struct GNUNET_PeerIdentity *peer,
3255                                    struct Session *session)
3256 {
3257   struct NeighbourMapEntry *n;
3258   struct BlackListCheckContext *bcc;
3259   struct BlackListCheckContext *bcc_next;
3260
3261   /* make sure to cancel all ongoing blacklist checks involving 'session' */
3262   bcc_next = bc_head;
3263   while (NULL != (bcc = bcc_next))
3264   {
3265     bcc_next = bcc->next;
3266     if (bcc->na.session == session)
3267     {
3268       if (NULL != bcc->bc)
3269         GST_blacklist_test_cancel (bcc->bc);
3270       GNUNET_HELLO_address_free (bcc->na.address);
3271       GNUNET_CONTAINER_DLL_remove (bc_head,
3272                                    bc_tail,
3273                                    bcc);
3274       GNUNET_free (bcc);
3275     }
3276   }
3277   if (NULL == (n = lookup_neighbour (peer)))
3278     return GNUNET_NO; /* can't affect us */
3279   if (session != n->primary_address.session)
3280   {
3281     /* Free alternative address */
3282     if (session == n->alternative_address.session)
3283     {
3284       if (GNUNET_TRANSPORT_PS_SWITCH_SYN_SENT == n->state)
3285         set_state_and_timeout (n,
3286                                GNUNET_TRANSPORT_PS_CONNECTED,
3287                                n->timeout);
3288       GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
3289                   "Session died, cleaning up alternative address\n");
3290       free_address (&n->alternative_address);
3291     }
3292     return GNUNET_NO; /* doesn't affect us further */
3293   }
3294
3295   n->expect_latency_response = GNUNET_NO;
3296   /* The session for neighbour's primary address died */
3297   switch (n->state)
3298   {
3299   case GNUNET_TRANSPORT_PS_NOT_CONNECTED:
3300     GNUNET_break (0);
3301     free_neighbour (n);
3302     return GNUNET_YES;
3303   case GNUNET_TRANSPORT_PS_INIT_ATS:
3304     GNUNET_break (0);
3305     free_neighbour (n);
3306     return GNUNET_YES;
3307   case GNUNET_TRANSPORT_PS_SYN_SENT:
3308     /* The session used to send the SYN terminated:
3309      * this implies a connect error*/
3310     GNUNET_log (GNUNET_ERROR_TYPE_INFO,
3311                 "Failed to send SYN in %s with `%s' %p: session terminated\n",
3312                 "CONNECT_SENT",
3313                 GST_plugins_a2s (n->primary_address.address),
3314                 n->primary_address.session,
3315                 GNUNET_i2s (peer));
3316
3317     /* Destroy the address since it cannot be used */
3318     unset_primary_address (n);
3319     set_state_and_timeout (n,
3320                            GNUNET_TRANSPORT_PS_INIT_ATS,
3321                            GNUNET_TIME_relative_to_absolute (ATS_RESPONSE_TIMEOUT));
3322     break;
3323   case GNUNET_TRANSPORT_PS_SYN_RECV_ATS:
3324   case GNUNET_TRANSPORT_PS_SYN_RECV_ACK:
3325     /* error on inbound session; free neighbour entirely */
3326     free_neighbour (n);
3327     return GNUNET_YES;
3328   case GNUNET_TRANSPORT_PS_CONNECTED:
3329     /* Our primary connection died, try a fast reconnect */
3330     unset_primary_address (n);
3331     set_state_and_timeout (n,
3332                            GNUNET_TRANSPORT_PS_RECONNECT_ATS,
3333                            GNUNET_TIME_relative_to_absolute (ATS_RESPONSE_TIMEOUT));
3334     break;
3335   case GNUNET_TRANSPORT_PS_RECONNECT_ATS:
3336     /* we don't have an address, how can it go down? */
3337     GNUNET_break (0);
3338     break;
3339   case GNUNET_TRANSPORT_PS_RECONNECT_SENT:
3340     GNUNET_log (GNUNET_ERROR_TYPE_INFO,
3341                 "Failed to send SYN in %s with `%s' %p: session terminated\n",
3342                 "RECONNECT_SENT",
3343                 GST_plugins_a2s (n->primary_address.address),
3344                 n->primary_address.session,
3345                 GNUNET_i2s (peer));
3346     /* Destroy the address since it cannot be used */
3347     unset_primary_address (n);
3348     set_state_and_timeout (n,
3349                            GNUNET_TRANSPORT_PS_RECONNECT_ATS,
3350                            GNUNET_TIME_relative_to_absolute (ATS_RESPONSE_TIMEOUT));
3351     break;
3352   case GNUNET_TRANSPORT_PS_SWITCH_SYN_SENT:
3353     /* primary went down while we were waiting for SYN_ACK on secondary;
3354        secondary as primary */
3355
3356     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
3357                 "Connection `%s' %p to peer `%s' was terminated while switching, "
3358                 "switching to alternative address `%s' %p\n",
3359                 GST_plugins_a2s (n->primary_address.address),
3360                 n->primary_address.session,
3361                 GNUNET_i2s (peer),
3362                 GST_plugins_a2s (n->alternative_address.address),
3363                 n->alternative_address.session);
3364
3365     /* Destroy the inbound address since it cannot be used */
3366     free_address (&n->primary_address);
3367     n->primary_address = n->alternative_address;
3368     memset (&n->alternative_address,
3369             0,
3370             sizeof (struct NeighbourAddress));
3371     set_state_and_timeout (n,
3372                            GNUNET_TRANSPORT_PS_RECONNECT_SENT,
3373                            GNUNET_TIME_relative_to_absolute (FAST_RECONNECT_TIMEOUT));
3374     break;
3375   case GNUNET_TRANSPORT_PS_DISCONNECT:
3376     unset_primary_address (n);
3377     break;
3378   case GNUNET_TRANSPORT_PS_DISCONNECT_FINISHED:
3379     /* neighbour was freed and plugins told to terminate session */
3380     return GNUNET_NO;
3381   default:
3382     GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
3383                 "Unhandled state `%s'\n",
3384                 GNUNET_TRANSPORT_ps2s (n->state));
3385     GNUNET_break (0);
3386     break;
3387   }
3388   if (NULL != n->task)
3389     GNUNET_SCHEDULER_cancel (n->task);
3390   n->task = GNUNET_SCHEDULER_add_now (&master_task, n);
3391   return GNUNET_YES;
3392 }
3393
3394
3395 /**
3396  * We received a 'ACK' message from the other peer.
3397  * If we sent a 'SYN_ACK' last, this means we are now
3398  * connected.  Otherwise, do nothing.
3399  *
3400  * @param message possibly a 'struct SessionConnectMessage' (check format)
3401  * @param address address of the other peer
3402  * @param session session to use (or NULL)
3403  * @return #GNUNET_OK if the message was fine, #GNUNET_SYSERR on serious error
3404  */
3405 int
3406 GST_neighbours_handle_session_ack (const struct GNUNET_MessageHeader *message,
3407                                    const struct GNUNET_HELLO_Address *address,
3408                                    struct Session *session)
3409 {
3410   struct NeighbourMapEntry *n;
3411
3412   if (ntohs (message->size) != sizeof (struct GNUNET_MessageHeader))
3413   {
3414     GNUNET_break_op (0);
3415     return GNUNET_SYSERR;
3416   }
3417   GNUNET_STATISTICS_update (GST_stats,
3418                             gettext_noop
3419                             ("# ACK messages received"),
3420                             1, GNUNET_NO);
3421   if (NULL == (n = lookup_neighbour (&address->peer)))
3422   {
3423     GNUNET_break_op (0);
3424     return GNUNET_SYSERR;
3425   }
3426   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
3427               "Received ACK for peer `%s' in state %s/%s\n",
3428               GNUNET_i2s (&address->peer),
3429               GNUNET_TRANSPORT_ps2s (n->state),
3430               print_ack_state (n->ack_state));
3431
3432   /* Check if we are in a plausible state for having sent
3433      a SYN_ACK.  If not, return, otherwise break.
3434
3435      The remote peers sends a ACK as a response for a SYN_ACK
3436      message.
3437
3438      We expect a ACK:
3439      - If a remote peer has sent a SYN, we responded with a SYN_ACK and
3440      now wait for the ACK to finally be connected
3441      - If we sent a SYN_ACK to this peer before */
3442
3443   if ( (GNUNET_TRANSPORT_PS_SYN_RECV_ACK != n->state) &&
3444        (ACK_SEND_ACK != n->ack_state))
3445   {
3446     GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
3447                 "Received unexpected ACK message from peer `%s' in state %s/%s\n",
3448                 GNUNET_i2s (&address->peer),
3449                 GNUNET_TRANSPORT_ps2s (n->state),
3450                 print_ack_state (n->ack_state));
3451
3452     GNUNET_STATISTICS_update (GST_stats,
3453                               gettext_noop ("# unexpected ACK messages"), 1,
3454                               GNUNET_NO);
3455     return GNUNET_OK;
3456   }
3457   if (GNUNET_TRANSPORT_PS_SWITCH_SYN_SENT == n->state)
3458   {
3459     /* We tried to switch addresses while being connect. We explicitly wait
3460      * for a SYN_ACK before going to GNUNET_TRANSPORT_PS_CONNECTED,
3461      * so we do not want to set the address as in use! */
3462     return GNUNET_OK;
3463   }
3464   set_state_and_timeout (n,
3465                          GNUNET_TRANSPORT_PS_CONNECTED,
3466                          GNUNET_TIME_relative_to_absolute (GNUNET_CONSTANTS_IDLE_CONNECTION_TIMEOUT));
3467
3468   /* Set primary address to used */
3469   set_primary_address (n,
3470                        n->primary_address.address,
3471                        n->primary_address.session,
3472                        n->primary_address.bandwidth_in,
3473                        n->primary_address.bandwidth_out);
3474   return GNUNET_OK;
3475 }
3476
3477
3478 /**
3479  * Test if we're connected to the given peer.
3480  *
3481  * @param target peer to test
3482  * @return #GNUNET_YES if we are connected, #GNUNET_NO if not
3483  */
3484 int
3485 GST_neighbours_test_connected (const struct GNUNET_PeerIdentity *target)
3486 {
3487   return test_connected (lookup_neighbour (target));
3488 }
3489
3490
3491 /**
3492  * Change the incoming quota for the given peer.
3493  *
3494  * @param neighbour identity of peer to change qutoa for
3495  * @param quota new quota
3496  */
3497 void
3498 GST_neighbours_set_incoming_quota (const struct GNUNET_PeerIdentity *neighbour,
3499                                    struct GNUNET_BANDWIDTH_Value32NBO quota)
3500 {
3501   struct NeighbourMapEntry *n;
3502
3503   if (NULL == (n = lookup_neighbour (neighbour)))
3504   {
3505     GNUNET_STATISTICS_update (GST_stats,
3506                               gettext_noop
3507                               ("# SET QUOTA messages ignored (no such peer)"),
3508                               1, GNUNET_NO);
3509     return;
3510   }
3511   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
3512               "Setting inbound quota of %u Bps for peer `%s' to all clients\n",
3513               ntohl (quota.value__), GNUNET_i2s (&n->id));
3514   GNUNET_BANDWIDTH_tracker_update_quota (&n->in_tracker, quota);
3515   if (0 != ntohl (quota.value__))
3516     return;
3517   GNUNET_log (GNUNET_ERROR_TYPE_INFO,
3518               "Disconnecting peer `%4s' due to SET_QUOTA\n",
3519               GNUNET_i2s (&n->id));
3520   if (GNUNET_YES == test_connected (n))
3521     GNUNET_STATISTICS_update (GST_stats,
3522                               gettext_noop ("# disconnects due to quota of 0"),
3523                               1, GNUNET_NO);
3524   disconnect_neighbour (n);
3525 }
3526
3527
3528 /**
3529  * Task to asynchronously run #free_neighbour().
3530  *
3531  * @param cls the `struct NeighbourMapEntry` to free
3532  * @param tc unused
3533  */
3534 static void
3535 delayed_disconnect (void *cls,
3536                     const struct GNUNET_SCHEDULER_TaskContext* tc)
3537 {
3538   struct NeighbourMapEntry *n = cls;
3539
3540   n->delayed_disconnect_task = NULL;
3541   GNUNET_log (GNUNET_ERROR_TYPE_INFO,
3542               "Disconnecting by request from peer %s\n",
3543               GNUNET_i2s (&n->id));
3544   free_neighbour (n);
3545 }
3546
3547
3548 /**
3549  * We received a disconnect message from the given peer,
3550  * validate and process.
3551  *
3552  * @param peer sender of the message
3553  * @param msg the disconnect message
3554  */
3555 void
3556 GST_neighbours_handle_disconnect_message (const struct GNUNET_PeerIdentity *peer,
3557                                           const struct GNUNET_MessageHeader *msg)
3558 {
3559   struct NeighbourMapEntry *n;
3560   const struct SessionDisconnectMessage *sdm;
3561
3562   GNUNET_log (GNUNET_ERROR_TYPE_INFO,
3563               "Received DISCONNECT message from peer `%s'\n",
3564               GNUNET_i2s (peer));
3565   if (ntohs (msg->size) != sizeof (struct SessionDisconnectMessage))
3566   {
3567     GNUNET_break_op (0);
3568     GNUNET_STATISTICS_update (GST_stats,
3569                               gettext_noop
3570                               ("# disconnect messages ignored (malformed)"), 1,
3571                               GNUNET_NO);
3572     return;
3573   }
3574   GNUNET_STATISTICS_update (GST_stats,
3575                             gettext_noop
3576                             ("# DISCONNECT messages received"),
3577                             1, GNUNET_NO);
3578   sdm = (const struct SessionDisconnectMessage *) msg;
3579   if (NULL == (n = lookup_neighbour (peer)))
3580   {
3581     /* gone already */
3582     return;
3583   }
3584   if (GNUNET_TIME_absolute_ntoh (sdm->timestamp).abs_value_us <= n->connect_ack_timestamp.abs_value_us)
3585   {
3586     GNUNET_STATISTICS_update (GST_stats,
3587                               gettext_noop ("# disconnect messages ignored (timestamp)"),
3588                               1,
3589                               GNUNET_NO);
3590     return;
3591   }
3592   if (0 != memcmp (peer,
3593                    &sdm->public_key,
3594                    sizeof (struct GNUNET_PeerIdentity)))
3595   {
3596     GNUNET_break_op (0);
3597     return;
3598   }
3599   if (ntohl (sdm->purpose.size) !=
3600       sizeof (struct GNUNET_CRYPTO_EccSignaturePurpose) +
3601       sizeof (struct GNUNET_CRYPTO_EddsaPublicKey) +
3602       sizeof (struct GNUNET_TIME_AbsoluteNBO))
3603   {
3604     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
3605                 "DISCONNECT message from peer `%s' has invalid size\n",
3606                 GNUNET_i2s (peer));
3607     GNUNET_break_op (0);
3608     return;
3609   }
3610   if (GNUNET_OK !=
3611       GNUNET_CRYPTO_eddsa_verify (GNUNET_MESSAGE_TYPE_TRANSPORT_SESSION_DISCONNECT,
3612                                   &sdm->purpose,
3613                                   &sdm->signature,
3614                                   &sdm->public_key))
3615   {
3616     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
3617                 "DISCONNECT message from peer `%s' cannot be verified \n",
3618                 GNUNET_i2s (peer));
3619     GNUNET_break_op (0);
3620     return;
3621   }
3622   n->delayed_disconnect_task = GNUNET_SCHEDULER_add_now (&delayed_disconnect, n);
3623 }
3624
3625
3626 /**
3627  * Closure for the #neighbours_iterate() function.
3628  */
3629 struct IteratorContext
3630 {
3631   /**
3632    * Function to call on each connected neighbour.
3633    */
3634   GST_NeighbourIterator cb;
3635
3636   /**
3637    * Closure for @e cb.
3638    */
3639   void *cb_cls;
3640 };
3641
3642
3643 /**
3644  * Call the callback from the closure for each neighbour.
3645  *
3646  * @param cls the `struct IteratorContext`
3647  * @param key the hash of the public key of the neighbour
3648  * @param value the `struct NeighbourMapEntry`
3649  * @return #GNUNET_OK (continue to iterate)
3650  */
3651 static int
3652 neighbours_iterate (void *cls,
3653                     const struct GNUNET_PeerIdentity *key,
3654                     void *value)
3655 {
3656   struct IteratorContext *ic = cls;
3657   struct NeighbourMapEntry *n = value;
3658   struct GNUNET_BANDWIDTH_Value32NBO bandwidth_in;
3659   struct GNUNET_BANDWIDTH_Value32NBO bandwidth_out;
3660
3661   if (NULL != n->primary_address.address)
3662   {
3663     bandwidth_in = n->primary_address.bandwidth_in;
3664     bandwidth_out = n->primary_address.bandwidth_out;
3665   }
3666   else
3667   {
3668     bandwidth_in = GNUNET_CONSTANTS_DEFAULT_BW_IN_OUT;
3669     bandwidth_out = GNUNET_CONSTANTS_DEFAULT_BW_IN_OUT;
3670   }
3671   ic->cb (ic->cb_cls,
3672           &n->id,
3673           n->primary_address.address,
3674           n->state,
3675           n->timeout,
3676           bandwidth_in, bandwidth_out);
3677   return GNUNET_OK;
3678 }
3679
3680
3681 /**
3682  * Iterate over all connected neighbours.
3683  *
3684  * @param cb function to call
3685  * @param cb_cls closure for cb
3686  */
3687 void
3688 GST_neighbours_iterate (GST_NeighbourIterator cb, void *cb_cls)
3689 {
3690   struct IteratorContext ic;
3691
3692   if (NULL == neighbours)
3693     return; /* can happen during shutdown */
3694   ic.cb = cb;
3695   ic.cb_cls = cb_cls;
3696   GNUNET_CONTAINER_multipeermap_iterate (neighbours,
3697                                          &neighbours_iterate,
3698                                          &ic);
3699 }
3700
3701
3702 /**
3703  * If we have an active connection to the given target, it must be shutdown.
3704  *
3705  * @param target peer to disconnect from
3706  */
3707 void
3708 GST_neighbours_force_disconnect (const struct GNUNET_PeerIdentity *target)
3709 {
3710   struct NeighbourMapEntry *n;
3711
3712   if (NULL == (n = lookup_neighbour (target)))
3713     return;  /* not active */
3714   if (GNUNET_YES == test_connected (n))
3715     GNUNET_STATISTICS_update (GST_stats,
3716                               gettext_noop ("# disconnected from peer upon explicit request"),
3717                               1,
3718                               GNUNET_NO);
3719   GNUNET_log (GNUNET_ERROR_TYPE_INFO,
3720               "Forced disconnect from peer %s\n",
3721               GNUNET_i2s (target));
3722   disconnect_neighbour (n);
3723 }
3724
3725
3726 /**
3727  * Obtain current address information for the given neighbour.
3728  *
3729  * @param peer
3730  * @return address currently used
3731  */
3732 struct GNUNET_HELLO_Address *
3733 GST_neighbour_get_current_address (const struct GNUNET_PeerIdentity *peer)
3734 {
3735   struct NeighbourMapEntry *n;
3736
3737   n = lookup_neighbour (peer);
3738   if (NULL == n)
3739     return NULL;
3740   return n->primary_address.address;
3741 }
3742
3743
3744 /**
3745  * Initialize the neighbours subsystem.
3746  *
3747  * @param max_fds maximum number of fds to use
3748  */
3749 void
3750 GST_neighbours_start (unsigned int max_fds)
3751 {
3752   neighbours = GNUNET_CONTAINER_multipeermap_create (NEIGHBOUR_TABLE_SIZE,
3753                                                      GNUNET_NO);
3754   util_transmission_tk = GNUNET_SCHEDULER_add_delayed (UTIL_TRANSMISSION_INTERVAL,
3755                                                        &utilization_transmission,
3756                                                        NULL);
3757 }
3758
3759
3760 /**
3761  * Disconnect from the given neighbour.
3762  *
3763  * @param cls unused
3764  * @param key hash of neighbour's public key (not used)
3765  * @param value the 'struct NeighbourMapEntry' of the neighbour
3766  * @return #GNUNET_OK (continue to iterate)
3767  */
3768 static int
3769 disconnect_all_neighbours (void *cls,
3770                            const struct GNUNET_PeerIdentity *key,
3771                            void *value)
3772 {
3773   struct NeighbourMapEntry *n = value;
3774
3775   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
3776               "Disconnecting peer `%4s' during shutdown\n",
3777               GNUNET_i2s (&n->id));
3778   free_neighbour (n);
3779   return GNUNET_OK;
3780 }
3781
3782
3783 /**
3784  * Cleanup the neighbours subsystem.
3785  */
3786 void
3787 GST_neighbours_stop ()
3788 {
3789   struct BlacklistCheckSwitchContext *cur;
3790   struct BlacklistCheckSwitchContext *next;
3791
3792   if (NULL == neighbours)
3793     return;
3794   if (NULL != util_transmission_tk)
3795   {
3796     GNUNET_SCHEDULER_cancel (util_transmission_tk);
3797     util_transmission_tk = NULL;
3798   }
3799   GNUNET_CONTAINER_multipeermap_iterate (neighbours,
3800                                          &disconnect_all_neighbours,
3801                                          NULL);
3802   GNUNET_CONTAINER_multipeermap_destroy (neighbours);
3803   neighbours = NULL;
3804   next = pending_bc_head;
3805   for (cur = next; NULL != cur; cur = next)
3806   {
3807     next = cur->next;
3808     GNUNET_CONTAINER_DLL_remove (pending_bc_head,
3809                                  pending_bc_tail,
3810                                  cur);
3811
3812     if (NULL != cur->blc)
3813     {
3814       GST_blacklist_test_cancel (cur->blc);
3815       cur->blc = NULL;
3816     }
3817     if (NULL != cur->address)
3818       GNUNET_HELLO_address_free (cur->address);
3819     GNUNET_free (cur);
3820   }
3821 }
3822
3823
3824 /* end of file gnunet-service-transport_neighbours.c */