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
|
/*
This file is part of GNUnet.
(C) 2010 Christian Grothoff
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 vpn/gnunet-daemon-vpn-dns.c
* @brief
* @author Philipp Toelke
*/
#include <platform.h>
#include <gnunet_common.h>
#include <gnunet_client_lib.h>
#include <gnunet_os_lib.h>
#include <gnunet_mesh_service.h>
#include <gnunet_protocols.h>
#include <gnunet_server_lib.h>
#include <gnunet_container_lib.h>
#include <block_dns.h>
#include "gnunet-daemon-vpn-dns.h"
#include "gnunet-daemon-vpn.h"
#include "gnunet-daemon-vpn-helper.h"
#include "gnunet-service-dns-p.h"
#include "gnunet-vpn-packet.h"
struct query_packet_list *head;
struct query_packet_list *tail;
struct GNUNET_CLIENT_Connection *dns_connection;
unsigned char restart_hijack;
struct answer_packet_list *answer_proc_head;
struct answer_packet_list *answer_proc_tail;
struct GNUNET_CLIENT_TransmitHandle *dns_transmit_handle;
/**
* Callback called by notify_transmit_ready; sends dns-queries or rehijack-messages
* to the service-dns
* {{{
*/
size_t
send_query (void *cls GNUNET_UNUSED, size_t size, void *buf)
{
size_t len;
dns_transmit_handle = NULL;
/*
* Send the rehijack-message
*/
if (restart_hijack == 1)
{
restart_hijack = 0;
/*
* The message is just a header
*/
GNUNET_assert (sizeof (struct GNUNET_MessageHeader) <= size);
struct GNUNET_MessageHeader *hdr = buf;
len = sizeof (struct GNUNET_MessageHeader);
hdr->size = htons (len);
hdr->type = htons (GNUNET_MESSAGE_TYPE_REHIJACK);
}
else if (head != NULL)
{
struct query_packet_list *query = head;
len = ntohs (query->pkt.hdr.size);
GNUNET_assert (len <= size);
memcpy (buf, &query->pkt.hdr, len);
GNUNET_CONTAINER_DLL_remove (head, tail, query);
GNUNET_free (query);
}
else
{
GNUNET_break (0);
len = 0;
}
/*
* Check whether more data is to be sent
*/
if (head != NULL)
{
dns_transmit_handle =
GNUNET_CLIENT_notify_transmit_ready (dns_connection,
ntohs (head->pkt.hdr.size),
GNUNET_TIME_UNIT_FOREVER_REL,
GNUNET_YES, &send_query, NULL);
}
else if (restart_hijack == 1)
{
dns_transmit_handle =
GNUNET_CLIENT_notify_transmit_ready (dns_connection,
sizeof (struct
GNUNET_MessageHeader),
GNUNET_TIME_UNIT_FOREVER_REL,
GNUNET_YES, &send_query, NULL);
}
return len;
}
/* }}} */
/**
* Connect to the service-dns
*/
void
connect_to_service_dns (void *cls
GNUNET_UNUSED,
const struct GNUNET_SCHEDULER_TaskContext *tc)
{
conn_task = GNUNET_SCHEDULER_NO_TASK;
if (0 != (tc->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN))
return;
GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Connecting to service-dns\n");
GNUNET_assert (dns_connection == NULL);
dns_connection = GNUNET_CLIENT_connect ("dns", cfg);
/* This would most likely be a misconfiguration */
GNUNET_assert (NULL != dns_connection);
GNUNET_CLIENT_receive (dns_connection, &dns_answer_handler, NULL,
GNUNET_TIME_UNIT_FOREVER_REL);
/* We might not yet be connected. Yay, mps. */
if (NULL == dns_connection)
return;
/* If a packet is already in the list, schedule to send it */
if (dns_transmit_handle == NULL && head != NULL)
dns_transmit_handle =
GNUNET_CLIENT_notify_transmit_ready (dns_connection,
ntohs (head->pkt.hdr.size),
GNUNET_TIME_UNIT_FOREVER_REL,
GNUNET_YES, &send_query, NULL);
else if (dns_transmit_handle == NULL && restart_hijack == 1)
{
dns_transmit_handle =
GNUNET_CLIENT_notify_transmit_ready (dns_connection,
sizeof (struct
GNUNET_MessageHeader),
GNUNET_TIME_UNIT_FOREVER_REL,
GNUNET_YES, &send_query, NULL);
}
}
/**
* This receives packets from the service-dns and schedules process_answer to
* handle it
*/
void
dns_answer_handler (void *cls
GNUNET_UNUSED,
const struct GNUNET_MessageHeader *msg)
{
/* the service disconnected, reconnect after short wait */
if (msg == NULL)
{
if (dns_transmit_handle != NULL)
GNUNET_CLIENT_notify_transmit_ready_cancel (dns_transmit_handle);
dns_transmit_handle = NULL;
GNUNET_CLIENT_disconnect (dns_connection, GNUNET_NO);
dns_connection = NULL;
conn_task =
GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_SECONDS,
&connect_to_service_dns, NULL);
return;
}
/* the service did something strange, reconnect immediately */
if (msg->type != htons (GNUNET_MESSAGE_TYPE_VPN_DNS_LOCAL_RESPONSE_DNS))
{
GNUNET_break (0);
GNUNET_CLIENT_disconnect (dns_connection, GNUNET_NO);
dns_connection = NULL;
conn_task = GNUNET_SCHEDULER_add_now (&connect_to_service_dns, NULL);
return;
}
void *pkt = GNUNET_malloc (ntohs (msg->size));
memcpy (pkt, msg, ntohs (msg->size));
GNUNET_SCHEDULER_add_now (process_answer, pkt);
GNUNET_CLIENT_receive (dns_connection, &dns_answer_handler, NULL,
GNUNET_TIME_UNIT_FOREVER_REL);
}
|
