aboutsummaryrefslogtreecommitdiff
path: root/src/transport/transport_api_address_to_string.c
blob: c7de39ea892f317e003dbd8173973609892bcd53 (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
/*
     This file is part of GNUnet.
     Copyright (C) 2009-2014, 2016 GNUnet e.V.

     GNUnet is free software: you can redistribute it and/or modify it
     under the terms of the GNU Affero General Public License as published
     by the Free Software Foundation, either version 3 of the License,
     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
     Affero General Public License for more details.

     You should have received a copy of the GNU Affero General Public License
     along with this program.  If not, see <http://www.gnu.org/licenses/>.

     SPDX-License-Identifier: AGPL3.0-or-later
 */
/**
 * @file transport/transport_api_address_to_string.c
 * @author Christian Grothoff
 * @brief enable clients to convert addresses to human readable strings
 */
#include "platform.h"
#include "gnunet_util_lib.h"
#include "gnunet_arm_service.h"
#include "gnunet_hello_lib.h"
#include "gnunet_protocols.h"
#include "gnunet_transport_service.h"
#include "transport.h"

/**
 * Context for the address lookup.
 */
struct GNUNET_TRANSPORT_AddressToStringContext
{
  /**
   * Function to call with the human-readable address.
   */
  GNUNET_TRANSPORT_AddressToStringCallback cb;

  /**
   * Closure for @e cb.
   */
  void *cb_cls;

  /**
   * Connection to the service.
   */
  struct GNUNET_MQ_Handle *mq;
};


/**
 * Function called with responses from the service.
 *
 * @param cls our `struct GNUNET_TRANSPORT_AddressToStringContext *`
 * @param msg message with the human-readable address
 * @return #GNUNET_OK if message is well-formed
 */
static int
check_reply (void *cls,
             const struct AddressToStringResultMessage *atsm)
{
  uint16_t size = ntohs (atsm->header.size) - sizeof(*atsm);
  const char *address;
  int result;
  uint32_t addr_len;

  result = (int) ntohl (atsm->res);
  addr_len = ntohl (atsm->addr_len);
  if (GNUNET_SYSERR == result)
    return GNUNET_OK;
  if (0 == size)
  {
    if (GNUNET_OK != result)
    {
      GNUNET_break (0);
      return GNUNET_SYSERR;
    }
    return GNUNET_OK;
  }
  address = (const char *) &atsm[1];
  if ((addr_len > size) ||
      (address[addr_len - 1] != '\0'))
  {
    /* invalid reply */
    GNUNET_break (0);
    return GNUNET_SYSERR;
  }
  return GNUNET_OK;
}


/**
 * Function called with responses from the service.
 *
 * @param cls our `struct GNUNET_TRANSPORT_AddressToStringContext *`
 * @param msg message with the human-readable address
 */
static void
handle_reply (void *cls,
              const struct AddressToStringResultMessage *atsm)
{
  struct GNUNET_TRANSPORT_AddressToStringContext *alucb = cls;
  uint16_t size = ntohs (atsm->header.size) - sizeof(*atsm);
  const char *address;
  int result;

  result = (int) ntohl (atsm->res);
  if (GNUNET_SYSERR == result)
  {
    /* expect more replies; as this is not the last
       call, we must pass the empty string for the address */
    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
                "Address resolution failed\n");
    alucb->cb (alucb->cb_cls,
               "",
               GNUNET_NO);
    return;
  }
  if (0 == size)
  {
    /* we are done (successfully, without communication errors) */
    alucb->cb (alucb->cb_cls,
               NULL,
               GNUNET_OK);
    GNUNET_TRANSPORT_address_to_string_cancel (alucb);
    return;
  }
  address = (const char *) &atsm[1];
  /* return normal reply to caller, also expect more replies */
  alucb->cb (alucb->cb_cls,
             address,
             GNUNET_OK);
}


/**
 * Generic error handler, called with the appropriate
 * error code and the same closure specified at the creation of
 * the message queue.
 * Not every message queue implementation supports an error handler.
 *
 * @param cls the `struct GNUNET_TRANSPORT_AddressToStringContext *`
 * @param error error code
 */
static void
mq_error_handler (void *cls,
                  enum GNUNET_MQ_Error error)
{
  struct GNUNET_TRANSPORT_AddressToStringContext *alucb = cls;

  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "Disconnected from transport, address resolution failed\n");
  alucb->cb (alucb->cb_cls,
             NULL,
             GNUNET_SYSERR);
  GNUNET_TRANSPORT_address_to_string_cancel (alucb);
}


/**
 * Convert a binary address into a human readable address.
 *
 * @param cfg configuration to use
 * @param address address to convert (binary format)
 * @param numeric should (IP) addresses be displayed in numeric form
 *                (otherwise do reverse DNS lookup)
 * @param timeout how long is the lookup allowed to take at most
 * @param aluc function to call with the results
 * @param aluc_cls closure for @a aluc
 * @return handle to cancel the operation, NULL on error
 */
struct GNUNET_TRANSPORT_AddressToStringContext *
GNUNET_TRANSPORT_address_to_string (const struct
                                    GNUNET_CONFIGURATION_Handle *cfg,
                                    const struct GNUNET_HELLO_Address *address,
                                    int numeric,
                                    struct GNUNET_TIME_Relative timeout,
                                    GNUNET_TRANSPORT_AddressToStringCallback
                                    aluc,
                                    void *aluc_cls)
{
  struct GNUNET_TRANSPORT_AddressToStringContext *alc
    = GNUNET_new (struct GNUNET_TRANSPORT_AddressToStringContext);
  struct GNUNET_MQ_MessageHandler handlers[] = {
    GNUNET_MQ_hd_var_size (reply,
                           GNUNET_MESSAGE_TYPE_TRANSPORT_ADDRESS_TO_STRING_REPLY,
                           struct AddressToStringResultMessage,
                           alc),
    GNUNET_MQ_handler_end ()
  };
  size_t alen;
  size_t slen;
  struct AddressLookupMessage *msg;
  struct GNUNET_MQ_Envelope *env;
  char *addrbuf;

  alen = address->address_length;
  slen = strlen (address->transport_name) + 1;
  if ((alen + slen >= GNUNET_MAX_MESSAGE_SIZE
       - sizeof(struct AddressLookupMessage)) ||
      (alen >= GNUNET_MAX_MESSAGE_SIZE) ||
      (slen >= GNUNET_MAX_MESSAGE_SIZE))
  {
    GNUNET_break (0);
    GNUNET_free (alc);
    return NULL;
  }
  alc->cb = aluc;
  alc->cb_cls = aluc_cls;
  alc->mq = GNUNET_CLIENT_connect (cfg,
                                   "transport",
                                   handlers,
                                   &mq_error_handler,
                                   alc);
  if (NULL == alc->mq)
  {
    GNUNET_break (0);
    GNUNET_free (alc);
    return NULL;
  }
  GNUNET_log (GNUNET_ERROR_TYPE_INFO,
              "Client tries to resolve for peer `%s' address plugin %s len %u\n",
              GNUNET_i2s (&address->peer),
              address->transport_name,
              (unsigned int) address->address_length);
  env = GNUNET_MQ_msg_extra (msg,
                             alen + slen,
                             GNUNET_MESSAGE_TYPE_TRANSPORT_ADDRESS_TO_STRING);
  msg->numeric_only = htons ((int16_t) numeric);
  msg->addrlen = htons ((uint16_t) alen);
  msg->timeout = GNUNET_TIME_relative_hton (timeout);
  addrbuf = (char *) &msg[1];
  GNUNET_memcpy (addrbuf,
                 address->address,
                 alen);
  GNUNET_memcpy (&addrbuf[alen],
                 address->transport_name,
                 slen);
  GNUNET_MQ_send (alc->mq,
                  env);
  return alc;
}


/**
 * Cancel request for address conversion.
 *
 * @param alc the context handle
 */
void
GNUNET_TRANSPORT_address_to_string_cancel (struct
                                           GNUNET_TRANSPORT_AddressToStringContext
                                           *alc)
{
  GNUNET_MQ_destroy (alc->mq);
  GNUNET_free (alc);
}


/* end of transport_api_address_to_string.c */