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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.
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.
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/>.
20 * @file dns/plugin_block_dns.c
21 * @brief block plugin for advertising a DNS exit service
22 * @author Christian Grothoff
24 * Note that this plugin might more belong with EXIT and PT
25 * as those two are using this type of block. Still, this
26 * might be a natural enough place for people to find the code...
29 #include "gnunet_block_plugin.h"
30 #include "block_dns.h"
31 #include "gnunet_signatures.h"
32 #include "gnunet_block_group_lib.h"
36 * Number of bits we set per entry in the bloomfilter.
39 #define BLOOMFILTER_K 16
43 * Create a new block group.
45 * @param ctx block context in which the block group is created
46 * @param type type of the block for which we are creating the group
47 * @param nonce random value used to seed the group creation
48 * @param raw_data optional serialized prior state of the group, NULL if unavailable/fresh
49 * @param raw_data_size number of bytes in @a raw_data, 0 if unavailable/fresh
50 * @param va variable arguments specific to @a type
51 * @return block group handle, NULL if block groups are not supported
52 * by this @a type of block (this is not an error)
54 static struct GNUNET_BLOCK_Group *
55 block_plugin_dns_create_group (void *cls,
56 enum GNUNET_BLOCK_Type type,
65 guard = va_arg (va, const char *);
66 if (0 == strcmp (guard,
68 bf_size = GNUNET_BLOCK_GROUP_compute_bloomfilter_size (va_arg (va, unsigned int),
70 else if (0 == strcmp (guard,
72 bf_size = va_arg (va, unsigned int);
78 GNUNET_break (NULL == va_arg (va, const char *));
79 return GNUNET_BLOCK_GROUP_bf_create (cls,
90 * Function called to validate a reply or a request. For
91 * request evaluation, simply pass "NULL" for the reply_block.
94 * @param ctx block context
95 * @param type block type
96 * @param bg group to evaluate against
97 * @param eo control flags
98 * @param query original query (hash)
99 * @param xquery extended query data (can be NULL, depending on type)
100 * @param xquery_size number of bytes in @a xquery
101 * @param reply_block response to validate
102 * @param reply_block_size number of bytes in @a reply_block
103 * @return characterization of result
105 static enum GNUNET_BLOCK_EvaluationResult
106 block_plugin_dns_evaluate (void *cls,
107 struct GNUNET_BLOCK_Context *ctx,
108 enum GNUNET_BLOCK_Type type,
109 struct GNUNET_BLOCK_Group *bg,
110 enum GNUNET_BLOCK_EvaluationOptions eo,
111 const struct GNUNET_HashCode * query,
114 const void *reply_block,
115 size_t reply_block_size)
117 const struct GNUNET_DNS_Advertisement *ad;
118 struct GNUNET_HashCode phash;
122 case GNUNET_BLOCK_TYPE_DNS:
123 if (0 != xquery_size)
124 return GNUNET_BLOCK_EVALUATION_REQUEST_INVALID;
126 if (NULL == reply_block)
127 return GNUNET_BLOCK_EVALUATION_REQUEST_VALID;
129 if (sizeof (struct GNUNET_DNS_Advertisement) != reply_block_size)
132 return GNUNET_BLOCK_EVALUATION_RESULT_INVALID;
136 if (ntohl (ad->purpose.size) !=
137 sizeof (struct GNUNET_DNS_Advertisement) -
138 sizeof (struct GNUNET_CRYPTO_EddsaSignature))
141 return GNUNET_BLOCK_EVALUATION_RESULT_INVALID;
144 GNUNET_TIME_absolute_get_remaining (GNUNET_TIME_absolute_ntoh
145 (ad->expiration_time)).rel_value_us)
147 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
148 "DNS advertisement has expired\n");
149 return GNUNET_BLOCK_EVALUATION_RESULT_INVALID;
152 GNUNET_CRYPTO_eddsa_verify (GNUNET_SIGNATURE_PURPOSE_DNS_RECORD,
155 &ad->peer.public_key))
158 return GNUNET_BLOCK_EVALUATION_RESULT_INVALID;
160 GNUNET_CRYPTO_hash (reply_block,
164 GNUNET_BLOCK_GROUP_bf_test_and_set (bg,
166 return GNUNET_BLOCK_EVALUATION_OK_DUPLICATE;
167 return GNUNET_BLOCK_EVALUATION_OK_MORE;
169 return GNUNET_BLOCK_EVALUATION_TYPE_NOT_SUPPORTED;
175 * Function called to obtain the key for a block.
178 * @param type block type
179 * @param block block to get the key for
180 * @param block_size number of bytes in @a block
181 * @param key set to the key (query) for the given block
182 * @return #GNUNET_OK on success, #GNUNET_SYSERR if type not supported
183 * (or if extracting a key from a block of this type does not work)
186 block_plugin_dns_get_key (void *cls,
187 enum GNUNET_BLOCK_Type type,
190 struct GNUNET_HashCode *key)
192 /* we cannot extract a key from a block of this type */
193 return GNUNET_SYSERR;
198 * Entry point for the plugin.
201 libgnunet_plugin_block_dns_init (void *cls)
203 static enum GNUNET_BLOCK_Type types[] =
205 GNUNET_BLOCK_TYPE_DNS,
206 GNUNET_BLOCK_TYPE_ANY /* end of list */
208 struct GNUNET_BLOCK_PluginFunctions *api;
210 api = GNUNET_new (struct GNUNET_BLOCK_PluginFunctions);
211 api->evaluate = &block_plugin_dns_evaluate;
212 api->get_key = &block_plugin_dns_get_key;
213 api->create_group = &block_plugin_dns_create_group;
220 * Exit point from the plugin.
223 libgnunet_plugin_block_dns_done (void *cls)
225 struct GNUNET_BLOCK_PluginFunctions *api = cls;
231 /* end of plugin_block_dns.c */