2 This file is part of GNUnet.
3 (C) 2001, 2002, 2004, 2005, 2007, 2009, 2010 Christian Grothoff (and other contributing authors)
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.
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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.
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16 along with GNUnet; see the file COPYING. If not, write to the
17 Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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22 * @file peerinfo/peerinfo_api_notify.c
23 * @brief notify API to access peerinfo service
24 * @author Christian Grothoff
27 #include "gnunet_client_lib.h"
28 #include "gnunet_peerinfo_service.h"
29 #include "gnunet_protocols.h"
30 #include "gnunet_time_lib.h"
34 * Context for the info handler.
36 struct GNUNET_PEERINFO_NotifyContext
40 * Our connection to the PEERINFO service.
42 struct GNUNET_CLIENT_Connection *client;
45 * Function to call with information.
47 GNUNET_PEERINFO_Processor callback;
50 * Closure for callback.
55 * Handle to our initial request for message transmission to
56 * the peerinfo service.
58 struct GNUNET_CLIENT_TransmitHandle *init;
63 const struct GNUNET_CONFIGURATION_Handle *cfg;
66 * Tasked used for delayed re-connection attempt.
68 GNUNET_SCHEDULER_TaskIdentifier task;
74 * Send a request to the peerinfo service to start being
75 * notified about all changes to peer information.
77 * @param nc our context
79 static void request_notifications (struct GNUNET_PEERINFO_NotifyContext *nc);
83 * Read notifications from the client handle and pass them
86 * @param nc our context
88 static void receive_notifications (struct GNUNET_PEERINFO_NotifyContext *nc);
92 * Task to re-try connecting to peerinfo.
94 * @param cls the 'struct GNUNET_PEERINFO_NotifyContext'
95 * @param tc scheduler context
98 reconnect (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
100 struct GNUNET_PEERINFO_NotifyContext *nc = cls;
102 nc->task = GNUNET_SCHEDULER_NO_TASK;
103 nc->client = GNUNET_CLIENT_connect ("peerinfo", nc->cfg);
104 if (NULL == nc->client)
108 GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_SECONDS, &reconnect, nc);
111 request_notifications (nc);
116 * Receive a peerinfo information message, process it and
120 * @param msg message received, NULL on timeout or fatal error
123 process_notification (void *cls, const struct GNUNET_MessageHeader *msg)
125 struct GNUNET_PEERINFO_NotifyContext *nc = cls;
126 const struct InfoMessage *im;
127 const struct GNUNET_HELLO_Message *hello;
132 GNUNET_CLIENT_disconnect (nc->client, GNUNET_NO);
133 reconnect (nc, NULL);
136 ms = ntohs (msg->size);
137 if ((ms < sizeof (struct InfoMessage)) ||
138 (ntohs (msg->type) != GNUNET_MESSAGE_TYPE_PEERINFO_INFO))
141 GNUNET_CLIENT_disconnect (nc->client, GNUNET_NO);
142 nc->client = GNUNET_CLIENT_connect ("peerinfo", nc->cfg);
143 request_notifications (nc);
146 im = (const struct InfoMessage *) msg;
148 if (ms > sizeof (struct InfoMessage) + sizeof (struct GNUNET_MessageHeader))
150 hello = (const struct GNUNET_HELLO_Message *) &im[1];
151 if (ms != sizeof (struct InfoMessage) + GNUNET_HELLO_size (hello))
154 GNUNET_CLIENT_disconnect (nc->client, GNUNET_NO);
155 nc->client = GNUNET_CLIENT_connect ("peerinfo", nc->cfg);
156 request_notifications (nc);
161 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
162 "Received information about peer `%s' from peerinfo database\n",
163 GNUNET_i2s (&im->peer));
165 nc->callback (nc->callback_cls, &im->peer, hello, NULL);
166 receive_notifications (nc);
171 * Read notifications from the client handle and pass them
174 * @param nc our context
177 receive_notifications (struct GNUNET_PEERINFO_NotifyContext *nc)
179 GNUNET_CLIENT_receive (nc->client, &process_notification, nc,
180 GNUNET_TIME_UNIT_FOREVER_REL);
185 * Transmit our init-notify request, start receiving.
187 * @param cls closure (our 'struct GNUNET_PEERINFO_NotifyContext')
188 * @param size number of bytes available in buf
189 * @param buf where the callee should write the message
190 * @return number of bytes written to buf
193 transmit_notify_request (void *cls, size_t size, void *buf)
195 struct GNUNET_PEERINFO_NotifyContext *nc = cls;
196 struct GNUNET_MessageHeader hdr;
201 GNUNET_CLIENT_disconnect (nc->client, GNUNET_NO);
202 nc->client = GNUNET_CLIENT_connect ("peerinfo", nc->cfg);
203 request_notifications (nc);
206 GNUNET_assert (size >= sizeof (struct GNUNET_MessageHeader));
207 hdr.size = htons (sizeof (struct GNUNET_MessageHeader));
208 hdr.type = htons (GNUNET_MESSAGE_TYPE_PEERINFO_NOTIFY);
209 memcpy (buf, &hdr, sizeof (struct GNUNET_MessageHeader));
210 receive_notifications (nc);
211 return sizeof (struct GNUNET_MessageHeader);
216 * Send a request to the peerinfo service to start being
217 * notified about all changes to peer information.
219 * @param nc our context
222 request_notifications (struct GNUNET_PEERINFO_NotifyContext *nc)
224 GNUNET_assert (NULL == nc->init);
226 GNUNET_CLIENT_notify_transmit_ready (nc->client,
227 sizeof (struct GNUNET_MessageHeader),
228 GNUNET_TIME_UNIT_FOREVER_REL,
229 GNUNET_YES, &transmit_notify_request,
235 * Call a method whenever our known information about peers
236 * changes. Initially calls the given function for all known
237 * peers and then only signals changes.
239 * @param cfg configuration to use
240 * @param callback the method to call for each peer
241 * @param callback_cls closure for callback
242 * @return NULL on error
244 struct GNUNET_PEERINFO_NotifyContext *
245 GNUNET_PEERINFO_notify (const struct GNUNET_CONFIGURATION_Handle *cfg,
246 GNUNET_PEERINFO_Processor callback, void *callback_cls)
248 struct GNUNET_PEERINFO_NotifyContext *nc;
249 struct GNUNET_CLIENT_Connection *client;
251 client = GNUNET_CLIENT_connect ("peerinfo", cfg);
254 GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
255 _("Could not connect to `%s' service.\n"), "peerinfo");
258 nc = GNUNET_malloc (sizeof (struct GNUNET_PEERINFO_NotifyContext));
261 nc->callback = callback;
262 nc->callback_cls = callback_cls;
263 request_notifications (nc);
269 * Stop notifying about changes.
271 * @param nc context to stop notifying
274 GNUNET_PEERINFO_notify_cancel (struct GNUNET_PEERINFO_NotifyContext *nc)
276 if (NULL != nc->init)
278 GNUNET_CLIENT_notify_transmit_ready_cancel (nc->init);
281 if (NULL != nc->client)
282 GNUNET_CLIENT_disconnect (nc->client, GNUNET_NO);
283 if (GNUNET_SCHEDULER_NO_TASK != nc->task)
284 GNUNET_SCHEDULER_cancel (nc->task);
288 /* end of peerinfo_api_notify.c */