aboutsummaryrefslogtreecommitdiff
path: root/src/peerinfo/peerinfo_api_notify.c
blob: b9e83c9e75344629f771fbc6371a4d977d07da3a (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
/*
     This file is part of GNUnet.
     (C) 2001, 2002, 2004, 2005, 2007, 2009, 2010 Christian Grothoff (and other contributing authors)

     GNUnet is free software; you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published
     by the Free Software Foundation; either version 3, or (at your
     option) any later version.

     GNUnet is distributed in the hope that it will be useful, but
     WITHOUT ANY WARRANTY; without even the implied warranty of
     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
     General Public License for more details.

     You should have received a copy of the GNU General Public License
     along with GNUnet; see the file COPYING.  If not, write to the
     Free Software Foundation, Inc., 59 Temple Place - Suite 330,
     Boston, MA 02111-1307, USA.
*/

/**
 * @file peerinfo/peerinfo_api_notify.c
 * @brief notify API to access peerinfo service
 * @author Christian Grothoff
 */
#include "platform.h"
#include "gnunet_client_lib.h"
#include "gnunet_peerinfo_service.h"
#include "gnunet_protocols.h"
#include "gnunet_time_lib.h"
#include "peerinfo.h"

#define LOG(kind,...) GNUNET_log_from (kind, "nse-api",__VA_ARGS__)

/**
 * Context for the info handler.
 */
struct GNUNET_PEERINFO_NotifyContext
{

  /**
   * Our connection to the PEERINFO service.
   */
  struct GNUNET_CLIENT_Connection *client;

  /**
   * Function to call with information.
   */
  GNUNET_PEERINFO_Processor callback;

  /**
   * Closure for callback.
   */
  void *callback_cls;

  /**
   * Handle to our initial request for message transmission to
   * the peerinfo service.
   */
  struct GNUNET_CLIENT_TransmitHandle *init;

  /**
   * Configuration.
   */
  const struct GNUNET_CONFIGURATION_Handle *cfg;

  /**
   * Tasked used for delayed re-connection attempt.
   */
  GNUNET_SCHEDULER_TaskIdentifier task;

};


/**
 * Send a request to the peerinfo service to start being
 * notified about all changes to peer information.
 *
 * @param nc our context
 */
static void
request_notifications (struct GNUNET_PEERINFO_NotifyContext *nc);


/**
 * Read notifications from the client handle and pass them
 * to the callback.
 *
 * @param nc our context
 */
static void
receive_notifications (struct GNUNET_PEERINFO_NotifyContext *nc);


/**
 * Task to re-try connecting to peerinfo.
 *
 * @param cls the 'struct GNUNET_PEERINFO_NotifyContext'
 * @param tc scheduler context
 */
static void
reconnect (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
{
  struct GNUNET_PEERINFO_NotifyContext *nc = cls;

  nc->task = GNUNET_SCHEDULER_NO_TASK;
  nc->client = GNUNET_CLIENT_connect ("peerinfo", nc->cfg);
  if (NULL == nc->client)
  {
    /* ugh */
    nc->task =
        GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_SECONDS, &reconnect, nc);
    return;
  }
  request_notifications (nc);
}


/**
 * Receive a peerinfo information message, process it and
 * go for more.
 *
 * @param cls closure
 * @param msg message received, NULL on timeout or fatal error
 */
static void
process_notification (void *cls, const struct GNUNET_MessageHeader *msg)
{
  struct GNUNET_PEERINFO_NotifyContext *nc = cls;
  const struct InfoMessage *im;
  const struct GNUNET_HELLO_Message *hello;
  uint16_t ms;

  if (msg == NULL)
  {
    GNUNET_CLIENT_disconnect (nc->client);
    reconnect (nc, NULL);
    return;
  }
  ms = ntohs (msg->size);
  if ((ms < sizeof (struct InfoMessage)) ||
      (ntohs (msg->type) != GNUNET_MESSAGE_TYPE_PEERINFO_INFO))
  {
    GNUNET_break (0);
    GNUNET_CLIENT_disconnect (nc->client);
    nc->client = GNUNET_CLIENT_connect ("peerinfo", nc->cfg);
    request_notifications (nc);
    return;
  }
  im = (const struct InfoMessage *) msg;
  hello = NULL;
  if (ms > sizeof (struct InfoMessage) + sizeof (struct GNUNET_MessageHeader))
  {
    hello = (const struct GNUNET_HELLO_Message *) &im[1];
    if (ms != sizeof (struct InfoMessage) + GNUNET_HELLO_size (hello))
    {
      GNUNET_break (0);
      GNUNET_CLIENT_disconnect (nc->client);
      nc->client = GNUNET_CLIENT_connect ("peerinfo", nc->cfg);
      request_notifications (nc);
      return;
    }
  }
  LOG (GNUNET_ERROR_TYPE_DEBUG,
       "Received information about peer `%s' from peerinfo database\n",
       GNUNET_i2s (&im->peer));
  nc->callback (nc->callback_cls, &im->peer, hello, NULL);
  receive_notifications (nc);
}


/**
 * Read notifications from the client handle and pass them
 * to the callback.
 *
 * @param nc our context
 */
static void
receive_notifications (struct GNUNET_PEERINFO_NotifyContext *nc)
{
  GNUNET_CLIENT_receive (nc->client, &process_notification, nc,
                         GNUNET_TIME_UNIT_FOREVER_REL);
}


/**
 * Transmit our init-notify request, start receiving.
 *
 * @param cls closure (our 'struct GNUNET_PEERINFO_NotifyContext')
 * @param size number of bytes available in buf
 * @param buf where the callee should write the message
 * @return number of bytes written to buf
 */
static size_t
transmit_notify_request (void *cls, size_t size, void *buf)
{
  struct GNUNET_PEERINFO_NotifyContext *nc = cls;
  struct GNUNET_MessageHeader hdr;

  nc->init = NULL;
  if (buf == NULL)
  {
    GNUNET_CLIENT_disconnect (nc->client);
    nc->client = GNUNET_CLIENT_connect ("peerinfo", nc->cfg);
    request_notifications (nc);
    return 0;
  }
  GNUNET_assert (size >= sizeof (struct GNUNET_MessageHeader));
  hdr.size = htons (sizeof (struct GNUNET_MessageHeader));
  hdr.type = htons (GNUNET_MESSAGE_TYPE_PEERINFO_NOTIFY);
  memcpy (buf, &hdr, sizeof (struct GNUNET_MessageHeader));
  receive_notifications (nc);
  return sizeof (struct GNUNET_MessageHeader);
}


/**
 * Send a request to the peerinfo service to start being
 * notified about all changes to peer information.
 *
 * @param nc our context
 */
static void
request_notifications (struct GNUNET_PEERINFO_NotifyContext *nc)
{
  GNUNET_assert (NULL == nc->init);
  nc->init =
      GNUNET_CLIENT_notify_transmit_ready (nc->client,
                                           sizeof (struct GNUNET_MessageHeader),
                                           GNUNET_TIME_UNIT_FOREVER_REL,
                                           GNUNET_YES, &transmit_notify_request,
                                           nc);
}


/**
 * Call a method whenever our known information about peers
 * changes.  Initially calls the given function for all known
 * peers and then only signals changes.
 *
 * @param cfg configuration to use
 * @param callback the method to call for each peer
 * @param callback_cls closure for callback
 * @return NULL on error
 */
struct GNUNET_PEERINFO_NotifyContext *
GNUNET_PEERINFO_notify (const struct GNUNET_CONFIGURATION_Handle *cfg,
                        GNUNET_PEERINFO_Processor callback, void *callback_cls)
{
  struct GNUNET_PEERINFO_NotifyContext *nc;
  struct GNUNET_CLIENT_Connection *client;

  client = GNUNET_CLIENT_connect ("peerinfo", cfg);
  if (client == NULL)
  {
    LOG (GNUNET_ERROR_TYPE_WARNING, _("Could not connect to `%s' service.\n"),
         "peerinfo");
    return NULL;
  }
  nc = GNUNET_malloc (sizeof (struct GNUNET_PEERINFO_NotifyContext));
  nc->cfg = cfg;
  nc->client = client;
  nc->callback = callback;
  nc->callback_cls = callback_cls;
  request_notifications (nc);
  return nc;
}


/**
 * Stop notifying about changes.
 *
 * @param nc context to stop notifying
 */
void
GNUNET_PEERINFO_notify_cancel (struct GNUNET_PEERINFO_NotifyContext *nc)
{
  if (NULL != nc->init)
  {
    GNUNET_CLIENT_notify_transmit_ready_cancel (nc->init);
    nc->init = NULL;
  }
  if (NULL != nc->client)
    GNUNET_CLIENT_disconnect (nc->client);
  if (GNUNET_SCHEDULER_NO_TASK != nc->task)
    GNUNET_SCHEDULER_cancel (nc->task);
  GNUNET_free (nc);
}

/* end of peerinfo_api_notify.c */