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Diffstat (limited to 'src/dns/gnunet-dns-redirector.c')
-rw-r--r-- | src/dns/gnunet-dns-redirector.c | 268 |
1 files changed, 0 insertions, 268 deletions
diff --git a/src/dns/gnunet-dns-redirector.c b/src/dns/gnunet-dns-redirector.c deleted file mode 100644 index 835497dba..000000000 --- a/src/dns/gnunet-dns-redirector.c +++ /dev/null | |||
@@ -1,268 +0,0 @@ | |||
1 | /* | ||
2 | This file is part of GNUnet. | ||
3 | Copyright (C) 2011 GNUnet e.V. | ||
4 | |||
5 | GNUnet is free software: you can redistribute it and/or modify it | ||
6 | under the terms of the GNU Affero General Public License as published | ||
7 | by the Free Software Foundation, either version 3 of the License, | ||
8 | or (at your 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 | Affero General Public License for more details. | ||
14 | |||
15 | You should have received a copy of the GNU Affero General Public License | ||
16 | along with this program. If not, see <http://www.gnu.org/licenses/>. | ||
17 | |||
18 | SPDX-License-Identifier: AGPL3.0-or-later | ||
19 | */ | ||
20 | |||
21 | /** | ||
22 | * @file src/dns/gnunet-dns-redirector.c | ||
23 | * @brief Tool to change DNS replies (for testing) | ||
24 | * @author Christian Grothoff | ||
25 | */ | ||
26 | |||
27 | #include "platform.h" | ||
28 | #include "gnunet_util_lib.h" | ||
29 | #include "gnunet_dns_service.h" | ||
30 | #include "gnunet_dnsparser_lib.h" | ||
31 | |||
32 | /** | ||
33 | * Handle to DNS service. | ||
34 | */ | ||
35 | static struct GNUNET_DNS_Handle *handle; | ||
36 | |||
37 | /** | ||
38 | * New target for A records. | ||
39 | */ | ||
40 | static char *n4; | ||
41 | |||
42 | /** | ||
43 | * New target for AAAA records. | ||
44 | */ | ||
45 | static char *n6; | ||
46 | |||
47 | /** | ||
48 | * Global return value (0 success). | ||
49 | */ | ||
50 | static int ret; | ||
51 | |||
52 | /** | ||
53 | * Selected level of verbosity. | ||
54 | */ | ||
55 | static unsigned int verbosity; | ||
56 | |||
57 | |||
58 | /** | ||
59 | * Modify the given DNS record. | ||
60 | * | ||
61 | * @param record record to modify | ||
62 | */ | ||
63 | static void | ||
64 | modify_record (const struct GNUNET_DNSPARSER_Record *record) | ||
65 | { | ||
66 | char buf[INET6_ADDRSTRLEN]; | ||
67 | |||
68 | switch (record->type) | ||
69 | { | ||
70 | case GNUNET_DNSPARSER_TYPE_A: | ||
71 | if (record->data.raw.data_len != sizeof(struct in_addr)) | ||
72 | return; | ||
73 | if (NULL != n4) | ||
74 | { | ||
75 | if (verbosity > 1) | ||
76 | fprintf (stderr, | ||
77 | "Changing A record from `%s' to `%s'\n", | ||
78 | inet_ntop (AF_INET, record->data.raw.data, buf, sizeof(buf)), | ||
79 | n4); | ||
80 | GNUNET_assert (1 == inet_pton (AF_INET, n4, record->data.raw.data)); | ||
81 | } | ||
82 | break; | ||
83 | |||
84 | case GNUNET_DNSPARSER_TYPE_AAAA: | ||
85 | if (record->data.raw.data_len != sizeof(struct in6_addr)) | ||
86 | return; | ||
87 | if (NULL != n6) | ||
88 | { | ||
89 | if (verbosity > 1) | ||
90 | fprintf (stderr, | ||
91 | "Changing AAAA record from `%s' to `%s'\n", | ||
92 | inet_ntop (AF_INET6, record->data.raw.data, buf, sizeof(buf)), | ||
93 | n6); | ||
94 | GNUNET_assert (1 == inet_pton (AF_INET6, n6, record->data.raw.data)); | ||
95 | } | ||
96 | break; | ||
97 | |||
98 | case GNUNET_DNSPARSER_TYPE_NS: | ||
99 | case GNUNET_DNSPARSER_TYPE_CNAME: | ||
100 | case GNUNET_DNSPARSER_TYPE_PTR: | ||
101 | case GNUNET_DNSPARSER_TYPE_SOA: | ||
102 | case GNUNET_DNSPARSER_TYPE_MX: | ||
103 | case GNUNET_DNSPARSER_TYPE_TXT: | ||
104 | break; | ||
105 | |||
106 | default: | ||
107 | break; | ||
108 | } | ||
109 | } | ||
110 | |||
111 | |||
112 | /** | ||
113 | * Signature of a function that is called whenever the DNS service | ||
114 | * encounters a DNS request and needs to do something with it. The | ||
115 | * function has then the chance to generate or modify the response by | ||
116 | * calling one of the three "GNUNET_DNS_request_*" continuations. | ||
117 | * | ||
118 | * When a request is intercepted, this function is called first to | ||
119 | * give the client a chance to do the complete address resolution; | ||
120 | * "rdata" will be NULL for this first call for a DNS request, unless | ||
121 | * some other client has already filled in a response. | ||
122 | * | ||
123 | * If multiple clients exist, all of them are called before the global | ||
124 | * DNS. The global DNS is only called if all of the clients' | ||
125 | * functions call GNUNET_DNS_request_forward. Functions that call | ||
126 | * GNUNET_DNS_request_forward will be called again before a final | ||
127 | * response is returned to the application. If any of the clients' | ||
128 | * functions call GNUNET_DNS_request_drop, the response is dropped. | ||
129 | * | ||
130 | * @param cls closure | ||
131 | * @param rh request handle to user for reply | ||
132 | * @param request_length number of bytes in request | ||
133 | * @param request udp payload of the DNS request | ||
134 | */ | ||
135 | static void | ||
136 | modify_request (void *cls, | ||
137 | struct GNUNET_DNS_RequestHandle *rh, | ||
138 | size_t request_length, | ||
139 | const char *request) | ||
140 | { | ||
141 | struct GNUNET_DNSPARSER_Packet *p; | ||
142 | unsigned int i; | ||
143 | char *buf; | ||
144 | size_t len; | ||
145 | int ret; | ||
146 | |||
147 | p = GNUNET_DNSPARSER_parse (request, request_length); | ||
148 | if (NULL == p) | ||
149 | { | ||
150 | fprintf (stderr, "Received malformed DNS packet, leaving it untouched\n"); | ||
151 | GNUNET_DNS_request_forward (rh); | ||
152 | return; | ||
153 | } | ||
154 | for (i = 0; i < p->num_answers; i++) | ||
155 | modify_record (&p->answers[i]); | ||
156 | buf = NULL; | ||
157 | ret = GNUNET_DNSPARSER_pack (p, 1024, &buf, &len); | ||
158 | GNUNET_DNSPARSER_free_packet (p); | ||
159 | if (GNUNET_OK != ret) | ||
160 | { | ||
161 | if (GNUNET_NO == ret) | ||
162 | fprintf (stderr, | ||
163 | "Modified DNS response did not fit, keeping old response\n"); | ||
164 | else | ||
165 | GNUNET_break (0); /* our modifications should have been sane! */ | ||
166 | GNUNET_DNS_request_forward (rh); | ||
167 | } | ||
168 | else | ||
169 | { | ||
170 | if (verbosity > 0) | ||
171 | fprintf (stdout, | ||
172 | "Injecting modified DNS response\n"); | ||
173 | GNUNET_DNS_request_answer (rh, len, buf); | ||
174 | } | ||
175 | GNUNET_free (buf); | ||
176 | } | ||
177 | |||
178 | |||
179 | /** | ||
180 | * Shutdown. | ||
181 | */ | ||
182 | static void | ||
183 | do_disconnect (void *cls) | ||
184 | { | ||
185 | if (NULL != handle) | ||
186 | { | ||
187 | GNUNET_DNS_disconnect (handle); | ||
188 | handle = NULL; | ||
189 | } | ||
190 | } | ||
191 | |||
192 | |||
193 | /** | ||
194 | * Main function that will be run by the scheduler. | ||
195 | * | ||
196 | * @param cls closure | ||
197 | * @param args remaining command-line arguments | ||
198 | * @param cfgfile name of the configuration file used (for saving, can be NULL!) | ||
199 | * @param cfg configuration | ||
200 | */ | ||
201 | static void | ||
202 | run (void *cls, char *const *args, const char *cfgfile, | ||
203 | const struct GNUNET_CONFIGURATION_Handle *cfg) | ||
204 | { | ||
205 | struct in_addr i4; | ||
206 | struct in6_addr i6; | ||
207 | |||
208 | if ((n4 != NULL) && | ||
209 | (1 != inet_pton (AF_INET, n4, &i4))) | ||
210 | { | ||
211 | fprintf (stderr, | ||
212 | "`%s' is nto a valid IPv4 address!\n", | ||
213 | n4); | ||
214 | return; | ||
215 | } | ||
216 | if ((n6 != NULL) && | ||
217 | (1 != inet_pton (AF_INET6, n6, &i6))) | ||
218 | { | ||
219 | fprintf (stderr, | ||
220 | "`%s' is nto a valid IPv6 address!\n", | ||
221 | n6); | ||
222 | return; | ||
223 | } | ||
224 | |||
225 | handle = | ||
226 | GNUNET_DNS_connect (cfg, | ||
227 | GNUNET_DNS_FLAG_POST_RESOLUTION, | ||
228 | &modify_request, | ||
229 | NULL); | ||
230 | GNUNET_SCHEDULER_add_shutdown (&do_disconnect, NULL); | ||
231 | } | ||
232 | |||
233 | |||
234 | int | ||
235 | main (int argc, char *const *argv) | ||
236 | { | ||
237 | struct GNUNET_GETOPT_CommandLineOption options[] = { | ||
238 | GNUNET_GETOPT_option_string ('4', | ||
239 | "ipv4", | ||
240 | "IPV4", | ||
241 | gettext_noop ("set A records"), | ||
242 | &n4), | ||
243 | |||
244 | GNUNET_GETOPT_option_string ('6', | ||
245 | "ipv4", | ||
246 | "IPV6", | ||
247 | gettext_noop ("set AAAA records"), | ||
248 | &n6), | ||
249 | |||
250 | GNUNET_GETOPT_option_verbose (&verbosity), | ||
251 | GNUNET_GETOPT_OPTION_END | ||
252 | }; | ||
253 | |||
254 | if (GNUNET_OK != GNUNET_STRINGS_get_utf8_args (argc, argv, &argc, &argv)) | ||
255 | return 2; | ||
256 | |||
257 | ret = (GNUNET_OK == | ||
258 | GNUNET_PROGRAM_run (argc, argv, "gnunet-dns-redirector", | ||
259 | gettext_noop | ||
260 | ("Change DNS replies to point elsewhere."), | ||
261 | options, | ||
262 | &run, NULL)) ? ret : 1; | ||
263 | GNUNET_free_nz ((void *) argv); | ||
264 | return ret; | ||
265 | } | ||
266 | |||
267 | |||
268 | /* end of gnunet-dns-redirector.c */ | ||