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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.
17 * @file dns/plugin_block_dns.c
18 * @brief block plugin for advertising a DNS exit service
19 * @author Christian Grothoff
21 * Note that this plugin might more belong with EXIT and PT
22 * as those two are using this type of block. Still, this
23 * might be a natural enough place for people to find the code...
26 #include "gnunet_block_plugin.h"
27 #include "block_dns.h"
28 #include "gnunet_signatures.h"
29 #include "gnunet_block_group_lib.h"
33 * Number of bits we set per entry in the bloomfilter.
36 #define BLOOMFILTER_K 16
40 * Create a new block group.
42 * @param ctx block context in which the block group is created
43 * @param type type of the block for which we are creating the group
44 * @param nonce random value used to seed the group creation
45 * @param raw_data optional serialized prior state of the group, NULL if unavailable/fresh
46 * @param raw_data_size number of bytes in @a raw_data, 0 if unavailable/fresh
47 * @param va variable arguments specific to @a type
48 * @return block group handle, NULL if block groups are not supported
49 * by this @a type of block (this is not an error)
51 static struct GNUNET_BLOCK_Group *
52 block_plugin_dns_create_group (void *cls,
53 enum GNUNET_BLOCK_Type type,
62 guard = va_arg (va, const char *);
63 if (0 == strcmp (guard,
65 bf_size = GNUNET_BLOCK_GROUP_compute_bloomfilter_size (va_arg (va, unsigned int),
67 else if (0 == strcmp (guard,
69 bf_size = va_arg (va, unsigned int);
75 GNUNET_break (NULL == va_arg (va, const char *));
76 return GNUNET_BLOCK_GROUP_bf_create (cls,
87 * Function called to validate a reply or a request. For
88 * request evaluation, simply pass "NULL" for the reply_block.
91 * @param ctx block context
92 * @param type block type
93 * @param bg group to evaluate against
94 * @param eo control flags
95 * @param query original query (hash)
96 * @param xquery extended query data (can be NULL, depending on type)
97 * @param xquery_size number of bytes in @a xquery
98 * @param reply_block response to validate
99 * @param reply_block_size number of bytes in @a reply_block
100 * @return characterization of result
102 static enum GNUNET_BLOCK_EvaluationResult
103 block_plugin_dns_evaluate (void *cls,
104 struct GNUNET_BLOCK_Context *ctx,
105 enum GNUNET_BLOCK_Type type,
106 struct GNUNET_BLOCK_Group *bg,
107 enum GNUNET_BLOCK_EvaluationOptions eo,
108 const struct GNUNET_HashCode * query,
111 const void *reply_block,
112 size_t reply_block_size)
114 const struct GNUNET_DNS_Advertisement *ad;
115 struct GNUNET_HashCode phash;
119 case GNUNET_BLOCK_TYPE_DNS:
120 if (0 != xquery_size)
121 return GNUNET_BLOCK_EVALUATION_REQUEST_INVALID;
123 if (NULL == reply_block)
124 return GNUNET_BLOCK_EVALUATION_REQUEST_VALID;
126 if (sizeof (struct GNUNET_DNS_Advertisement) != reply_block_size)
129 return GNUNET_BLOCK_EVALUATION_RESULT_INVALID;
133 if (ntohl (ad->purpose.size) !=
134 sizeof (struct GNUNET_DNS_Advertisement) -
135 sizeof (struct GNUNET_CRYPTO_EddsaSignature))
138 return GNUNET_BLOCK_EVALUATION_RESULT_INVALID;
141 GNUNET_TIME_absolute_get_remaining (GNUNET_TIME_absolute_ntoh
142 (ad->expiration_time)).rel_value_us)
144 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
145 "DNS advertisement has expired\n");
146 return GNUNET_BLOCK_EVALUATION_RESULT_INVALID;
149 GNUNET_CRYPTO_eddsa_verify (GNUNET_SIGNATURE_PURPOSE_DNS_RECORD,
152 &ad->peer.public_key))
155 return GNUNET_BLOCK_EVALUATION_RESULT_INVALID;
157 GNUNET_CRYPTO_hash (reply_block,
161 GNUNET_BLOCK_GROUP_bf_test_and_set (bg,
163 return GNUNET_BLOCK_EVALUATION_OK_DUPLICATE;
164 return GNUNET_BLOCK_EVALUATION_OK_MORE;
166 return GNUNET_BLOCK_EVALUATION_TYPE_NOT_SUPPORTED;
172 * Function called to obtain the key for a block.
175 * @param type block type
176 * @param block block to get the key for
177 * @param block_size number of bytes in @a block
178 * @param key set to the key (query) for the given block
179 * @return #GNUNET_OK on success, #GNUNET_SYSERR if type not supported
180 * (or if extracting a key from a block of this type does not work)
183 block_plugin_dns_get_key (void *cls,
184 enum GNUNET_BLOCK_Type type,
187 struct GNUNET_HashCode *key)
189 /* we cannot extract a key from a block of this type */
190 return GNUNET_SYSERR;
195 * Entry point for the plugin.
198 libgnunet_plugin_block_dns_init (void *cls)
200 static enum GNUNET_BLOCK_Type types[] =
202 GNUNET_BLOCK_TYPE_DNS,
203 GNUNET_BLOCK_TYPE_ANY /* end of list */
205 struct GNUNET_BLOCK_PluginFunctions *api;
207 api = GNUNET_new (struct GNUNET_BLOCK_PluginFunctions);
208 api->evaluate = &block_plugin_dns_evaluate;
209 api->get_key = &block_plugin_dns_get_key;
210 api->create_group = &block_plugin_dns_create_group;
217 * Exit point from the plugin.
220 libgnunet_plugin_block_dns_done (void *cls)
222 struct GNUNET_BLOCK_PluginFunctions *api = cls;
228 /* end of plugin_block_dns.c */