src/transport/transport_api_peer_address_lookup.c

   1 /*
   2      This file is part of GNUnet.
   3      (C) 2009, 2010 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/transport_api_peer_address_lookup.c
  23  * @brief given a peer id, get all known addresses from transport service
  24  *
  25  * This api provides the ability to query the transport service about
  26  * the status of connections to a specific peer.  Calls back with a
  27  * pretty printed string of the address, as formatted by the appropriate
  28  * transport plugin, and whether or not the address given is currently
  29  * in the 'connected' state (according to the transport service).
  30  */
  31
  32 #include "platform.h"
  33 #include "gnunet_client_lib.h"
  34 #include "gnunet_arm_service.h"
  35 #include "gnunet_hello_lib.h"
  36 #include "gnunet_protocols.h"
  37 #include "gnunet_server_lib.h"
  38 #include "gnunet_time_lib.h"
  39 #include "gnunet_transport_service.h"
  40 #include "transport.h"
  41
  42 /**
  43  * Context for the address lookup.
  44  */
  45 struct AddressLookupCtx
  46 {
  47   /**
  48    * Function to call with the human-readable address.
  49    */
  50   GNUNET_TRANSPORT_AddressLookUpCallback cb;
  51
  52   /**
  53    * Closure for cb.
  54    */
  55   void *cb_cls;
  56
  57   /**
  58    * Connection to the service.
  59    */
  60   struct GNUNET_CLIENT_Connection *client;
  61
  62   /**
  63    * When should this operation time out?
  64    */
  65   struct GNUNET_TIME_Absolute timeout;
  66 };
  67
  68
  69 /**
  70  * Function called with responses from the service.
  71  *
  72  * @param cls our 'struct AddressLookupCtx*'
  73  * @param msg NULL on timeout or error, otherwise presumably a
  74  *        message with the human-readable address
  75  */
  76 static void
  77 peer_address_response_processor (void *cls,
  78                                  const struct GNUNET_MessageHeader *msg)
  79 {
  80   struct AddressLookupCtx *alucb = cls;
  81   const char *address;
  82   uint16_t size;
  83
  84   if (msg == NULL)
  85     {
  86       alucb->cb (alucb->cb_cls, NULL);
  87       GNUNET_CLIENT_disconnect (alucb->client, GNUNET_NO);
  88       GNUNET_free (alucb);
  89       return;
  90     }
  91   GNUNET_break (ntohs (msg->type) == GNUNET_MESSAGE_TYPE_TRANSPORT_ADDRESS_REPLY);
  92   size = ntohs (msg->size);
  93   if (size == sizeof (struct GNUNET_MessageHeader))
  94     {
  95       /* done! */
  96       alucb->cb (alucb->cb_cls, NULL);
  97       GNUNET_CLIENT_disconnect (alucb->client, GNUNET_NO);
  98       GNUNET_free (alucb);
  99       return;
 100     }
 101   address = (const char *) &msg[1];
 102   if (address[size - sizeof (struct GNUNET_MessageHeader) - 1] != '\0')
 103     {
 104       /* invalid reply */
 105       GNUNET_break (0);
 106       alucb->cb (alucb->cb_cls, NULL);
 107       GNUNET_CLIENT_disconnect (alucb->client, GNUNET_NO);
 108       GNUNET_free (alucb);
 109       return;
 110     }
 111   /* expect more replies */
 112   GNUNET_CLIENT_receive (alucb->client,
 113                          &peer_address_response_processor, alucb,
 114                          GNUNET_TIME_absolute_get_remaining
 115                          (alucb->timeout));
 116   alucb->cb (alucb->cb_cls, address);
 117 }
 118
 119
 120 /**
 121  * Return all the known addresses for a peer.
 122  *
 123  * @param cfg configuration to use
 124  * @param peer peer identity to look up the addresses of
 125  * @param timeout how long is the lookup allowed to take at most
 126  * @param peer_address_callback function to call with the results
 127  * @param peer_address_callback_cls closure for peer_address_callback
 128  */
 129 void
 130 GNUNET_TRANSPORT_peer_address_lookup (const struct GNUNET_CONFIGURATION_Handle *cfg,
 131                                       const struct GNUNET_PeerIdentity *peer,
 132                                       struct GNUNET_TIME_Relative timeout,
 133                                       GNUNET_TRANSPORT_AddressLookUpCallback peer_address_callback,
 134                                       void *peer_address_callback_cls)
 135 {
 136   struct PeerAddressLookupMessage msg;
 137   struct AddressLookupCtx *peer_address_lookup_cb;
 138   struct GNUNET_CLIENT_Connection *client;
 139
 140   client = GNUNET_CLIENT_connect ("transport", cfg);
 141   if (client == NULL)
 142     {
 143       peer_address_callback (peer_address_callback_cls, NULL);
 144       return;
 145     }
 146   msg.header.size = htons (sizeof(struct PeerAddressLookupMessage));
 147   msg.header.type = htons (GNUNET_MESSAGE_TYPE_TRANSPORT_PEER_ADDRESS_LOOKUP);
 148   msg.timeout = GNUNET_TIME_relative_hton (timeout);
 149   memcpy(&msg.peer, peer, sizeof(struct GNUNET_PeerIdentity));
 150   peer_address_lookup_cb = GNUNET_malloc (sizeof (struct AddressLookupCtx));
 151   peer_address_lookup_cb->cb = peer_address_callback;
 152   peer_address_lookup_cb->cb_cls = peer_address_callback_cls;
 153   peer_address_lookup_cb->timeout = GNUNET_TIME_relative_to_absolute (timeout);
 154   peer_address_lookup_cb->client = client;
 155   GNUNET_assert (GNUNET_OK ==
 156                  GNUNET_CLIENT_transmit_and_get_response (client,
 157                                                           &msg.header,
 158                                                           timeout,
 159                                                           GNUNET_YES,
 160                                                           &peer_address_response_processor,
 161                                                           peer_address_lookup_cb));
 162 }
 163
 164 /* end of transport_api_peer_address_lookup.c */