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 #include "platform.h"
  21 #include "gnunet_client_lib.h"
  22 #include "gnunet_arm_service.h"
  23 #include "gnunet_hello_lib.h"
  24 #include "gnunet_protocols.h"
  25 #include "gnunet_server_lib.h"
  26 #include "gnunet_time_lib.h"
  27 #include "gnunet_transport_service.h"
  28 #include "transport.h"
  29
  30 /**
  31  * Context for the address lookup.
  32  */
  33 struct AddressLookupCtx
  34 {
  35   /**
  36    * Function to call with the human-readable address.
  37    */
  38   GNUNET_TRANSPORT_AddressLookUpCallback cb;
  39
  40   /**
  41    * Closure for cb.
  42    */
  43   void *cb_cls;
  44
  45   /**
  46    * Connection to the service.
  47    */
  48   struct GNUNET_CLIENT_Connection *client;
  49
  50   /**
  51    * When should this operation time out?
  52    */
  53   struct GNUNET_TIME_Absolute timeout;
  54 };
  55
  56
  57 /**
  58  * Function called with responses from the service.
  59  *
  60  * @param cls our 'struct AddressLookupCtx*'
  61  * @param msg NULL on timeout or error, otherwise presumably a
  62  *        message with the human-readable address
  63  */
  64 static void
  65 peer_address_response_processor (void *cls,
  66                                  const struct GNUNET_MessageHeader *msg)
  67 {
  68   struct AddressLookupCtx *alucb = cls;
  69   const char *address;
  70   uint16_t size;
  71
  72   if (msg == NULL)
  73     {
  74       alucb->cb (alucb->cb_cls, NULL);
  75       GNUNET_CLIENT_disconnect (alucb->client, GNUNET_NO);
  76       GNUNET_free (alucb);
  77       return;
  78     }
  79   GNUNET_break (ntohs (msg->type) == GNUNET_MESSAGE_TYPE_TRANSPORT_ADDRESS_REPLY);
  80   size = ntohs (msg->size);
  81   if (size == sizeof (struct GNUNET_MessageHeader))
  82     {
  83       /* done! */
  84       alucb->cb (alucb->cb_cls, NULL);
  85       GNUNET_CLIENT_disconnect (alucb->client, GNUNET_NO);
  86       GNUNET_free (alucb);
  87       return;
  88     }
  89   address = (const char *) &msg[1];
  90   if (address[size - sizeof (struct GNUNET_MessageHeader) - 1] != '\0')
  91     {
  92       /* invalid reply */
  93       GNUNET_break (0);
  94       alucb->cb (alucb->cb_cls, NULL);
  95       GNUNET_CLIENT_disconnect (alucb->client, GNUNET_NO);
  96       GNUNET_free (alucb);
  97       return;
  98     }
  99   /* expect more replies */
 100   GNUNET_CLIENT_receive (alucb->client,
 101                          &peer_address_response_processor, alucb,
 102                          GNUNET_TIME_absolute_get_remaining
 103                          (alucb->timeout));
 104   alucb->cb (alucb->cb_cls, address);
 105 }
 106
 107
 108 /**
 109  * Return all the known addresses for a peer.
 110  *
 111  * @param cfg configuration to use
 112  * @param peer peer identity to look up the addresses of
 113  * @param timeout how long is the lookup allowed to take at most
 114  * @param peer_address_callback function to call with the results
 115  * @param peer_address_callback_cls closure for peer_address_callback
 116  */
 117 void
 118 GNUNET_TRANSPORT_peer_address_lookup (const struct GNUNET_CONFIGURATION_Handle *cfg,
 119                                       const struct GNUNET_PeerIdentity *peer,
 120                                       struct GNUNET_TIME_Relative timeout,
 121                                       GNUNET_TRANSPORT_AddressLookUpCallback peer_address_callback,
 122                                       void *peer_address_callback_cls)
 123 {
 124   struct PeerAddressLookupMessage msg;
 125   struct GNUNET_TIME_Absolute abs_timeout;
 126   struct AddressLookupCtx *peer_address_lookup_cb;
 127   struct GNUNET_CLIENT_Connection *client;
 128
 129   client = GNUNET_CLIENT_connect ("transport", cfg);
 130   if (client == NULL)
 131     {
 132       peer_address_callback (peer_address_callback_cls, NULL);
 133       return;
 134     }
 135   abs_timeout = GNUNET_TIME_relative_to_absolute (timeout);
 136
 137   msg.header.size = htons (sizeof(struct PeerAddressLookupMessage));
 138   msg.header.type = htons (GNUNET_MESSAGE_TYPE_TRANSPORT_PEER_ADDRESS_LOOKUP);
 139   msg.timeout = GNUNET_TIME_absolute_hton (abs_timeout);
 140   memcpy(&msg.peer, peer, sizeof(struct GNUNET_PeerIdentity));
 141   peer_address_lookup_cb = GNUNET_malloc (sizeof (struct AddressLookupCtx));
 142   peer_address_lookup_cb->cb = peer_address_callback;
 143   peer_address_lookup_cb->cb_cls = peer_address_callback_cls;
 144   peer_address_lookup_cb->timeout = abs_timeout;
 145   peer_address_lookup_cb->client = client;
 146   GNUNET_assert (GNUNET_OK ==
 147                  GNUNET_CLIENT_transmit_and_get_response (client,
 148                                                           &msg.header,
 149                                                           timeout,
 150                                                           GNUNET_YES,
 151                                                           &peer_address_response_processor,
 152                                                           peer_address_lookup_cb));
 153 }
 154
 155 /* end of transport_api_peer_address_lookup.c */