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3 Copyright (C) 2013, 2017 GNUnet e.V.
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.
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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 Affero General Public License for more details.
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/>.
18 SPDX-License-Identifier: AGPL3.0-or-later
22 * @file dns/plugin_block_dns.c
23 * @brief block plugin for advertising a DNS exit service
24 * @author Christian Grothoff
26 * Note that this plugin might more belong with EXIT and PT
27 * as those two are using this type of block. Still, this
28 * might be a natural enough place for people to find the code...
31 #include "gnunet_block_plugin.h"
32 #include "block_dns.h"
33 #include "gnunet_signatures.h"
34 #include "gnunet_block_group_lib.h"
38 * Number of bits we set per entry in the bloomfilter.
41 #define BLOOMFILTER_K 16
45 * Create a new block group.
47 * @param ctx block context in which the block group is created
48 * @param type type of the block for which we are creating the group
49 * @param nonce random value used to seed the group creation
50 * @param raw_data optional serialized prior state of the group, NULL if unavailable/fresh
51 * @param raw_data_size number of bytes in @a raw_data, 0 if unavailable/fresh
52 * @param va variable arguments specific to @a type
53 * @return block group handle, NULL if block groups are not supported
54 * by this @a type of block (this is not an error)
56 static struct GNUNET_BLOCK_Group *
57 block_plugin_dns_create_group (void *cls,
58 enum GNUNET_BLOCK_Type type,
67 guard = va_arg (va, const char *);
68 if (0 == strcmp (guard,
70 bf_size = GNUNET_BLOCK_GROUP_compute_bloomfilter_size (va_arg (va, unsigned
73 else if (0 == strcmp (guard,
75 bf_size = va_arg (va, unsigned int);
81 GNUNET_break (NULL == va_arg (va, const char *));
82 return GNUNET_BLOCK_GROUP_bf_create (cls,
93 * Function called to validate a reply or a request. For
94 * request evaluation, simply pass "NULL" for the reply_block.
97 * @param ctx block context
98 * @param type block type
99 * @param bg group to evaluate against
100 * @param eo control flags
101 * @param query original query (hash)
102 * @param xquery extended query data (can be NULL, depending on type)
103 * @param xquery_size number of bytes in @a xquery
104 * @param reply_block response to validate
105 * @param reply_block_size number of bytes in @a reply_block
106 * @return characterization of result
108 static enum GNUNET_BLOCK_EvaluationResult
109 block_plugin_dns_evaluate (void *cls,
110 struct GNUNET_BLOCK_Context *ctx,
111 enum GNUNET_BLOCK_Type type,
112 struct GNUNET_BLOCK_Group *bg,
113 enum GNUNET_BLOCK_EvaluationOptions eo,
114 const struct GNUNET_HashCode *query,
117 const void *reply_block,
118 size_t reply_block_size)
120 const struct GNUNET_DNS_Advertisement *ad;
121 struct GNUNET_HashCode phash;
125 case GNUNET_BLOCK_TYPE_DNS:
126 if (0 != xquery_size)
127 return GNUNET_BLOCK_EVALUATION_REQUEST_INVALID;
129 if (NULL == reply_block)
130 return GNUNET_BLOCK_EVALUATION_REQUEST_VALID;
132 if (sizeof(struct GNUNET_DNS_Advertisement) != reply_block_size)
135 return GNUNET_BLOCK_EVALUATION_RESULT_INVALID;
139 if (ntohl (ad->purpose.size) !=
140 sizeof(struct GNUNET_DNS_Advertisement)
141 - sizeof(struct GNUNET_CRYPTO_EddsaSignature))
144 return GNUNET_BLOCK_EVALUATION_RESULT_INVALID;
147 GNUNET_TIME_absolute_get_remaining (GNUNET_TIME_absolute_ntoh
148 (ad->expiration_time)).
151 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
152 "DNS advertisement has expired\n");
153 return GNUNET_BLOCK_EVALUATION_RESULT_INVALID;
156 GNUNET_CRYPTO_eddsa_verify (GNUNET_SIGNATURE_PURPOSE_DNS_RECORD,
159 &ad->peer.public_key))
162 return GNUNET_BLOCK_EVALUATION_RESULT_INVALID;
164 GNUNET_CRYPTO_hash (reply_block,
168 GNUNET_BLOCK_GROUP_bf_test_and_set (bg,
170 return GNUNET_BLOCK_EVALUATION_OK_DUPLICATE;
171 return GNUNET_BLOCK_EVALUATION_OK_MORE;
174 return GNUNET_BLOCK_EVALUATION_TYPE_NOT_SUPPORTED;
180 * Function called to obtain the key for a block.
183 * @param type block type
184 * @param block block to get the key for
185 * @param block_size number of bytes in @a block
186 * @param key set to the key (query) for the given block
187 * @return #GNUNET_OK on success, #GNUNET_SYSERR if type not supported
188 * (or if extracting a key from a block of this type does not work)
191 block_plugin_dns_get_key (void *cls,
192 enum GNUNET_BLOCK_Type type,
195 struct GNUNET_HashCode *key)
197 /* we cannot extract a key from a block of this type */
198 return GNUNET_SYSERR;
203 * Entry point for the plugin.
206 libgnunet_plugin_block_dns_init (void *cls)
208 static enum GNUNET_BLOCK_Type types[] = {
209 GNUNET_BLOCK_TYPE_DNS,
210 GNUNET_BLOCK_TYPE_ANY /* end of list */
212 struct GNUNET_BLOCK_PluginFunctions *api;
214 api = GNUNET_new (struct GNUNET_BLOCK_PluginFunctions);
215 api->evaluate = &block_plugin_dns_evaluate;
216 api->get_key = &block_plugin_dns_get_key;
217 api->create_group = &block_plugin_dns_create_group;
224 * Exit point from the plugin.
227 libgnunet_plugin_block_dns_done (void *cls)
229 struct GNUNET_BLOCK_PluginFunctions *api = cls;
236 /* end of plugin_block_dns.c */