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
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
|
/*
This file is part of GNUnet
Copyright (C) 2010-2013 GNUnet e.V.
GNUnet is free software: you can redistribute it and/or modify it
under the terms of the GNU Affero General Public License as published
by the Free Software Foundation, either version 3 of the License,
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
Affero General Public License for more details.
You should have received a copy of the GNU Affero General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
/**
* @file gns/plugin_block_gns.c
* @brief blocks used for GNS records
* @author Martin Schanzenbach
* @author Christian Grothoff
*/
#include "platform.h"
#include "gnunet_block_group_lib.h"
#include "gnunet_block_plugin.h"
#include "gnunet_namestore_service.h"
#include "gnunet_signatures.h"
/**
* Number of bits we set per entry in the bloomfilter.
* Do not change! -from fs
*/
#define BLOOMFILTER_K 16
/**
* How big is the BF we use for GNS blocks?
*/
#define GNS_BF_SIZE 8
/**
* Create a new block group.
*
* @param ctx block context in which the block group is created
* @param type type of the block for which we are creating the group
* @param nonce random value used to seed the group creation
* @param raw_data optional serialized prior state of the group, NULL if unavailable/fresh
* @param raw_data_size number of bytes in @a raw_data, 0 if unavailable/fresh
* @param va variable arguments specific to @a type
* @return block group handle, NULL if block groups are not supported
* by this @a type of block (this is not an error)
*/
static struct GNUNET_BLOCK_Group *
block_plugin_gns_create_group (void *cls,
enum GNUNET_BLOCK_Type type,
uint32_t nonce,
const void *raw_data,
size_t raw_data_size,
va_list va)
{
unsigned int bf_size;
const char *guard;
guard = va_arg (va, const char *);
if (0 == strcmp (guard,
"seen-set-size"))
bf_size = GNUNET_BLOCK_GROUP_compute_bloomfilter_size (va_arg (va, unsigned int),
BLOOMFILTER_K);
else if (0 == strcmp (guard,
"filter-size"))
bf_size = va_arg (va, unsigned int);
else
{
GNUNET_break (0);
bf_size = GNS_BF_SIZE;
}
GNUNET_break (NULL == va_arg (va, const char *));
return GNUNET_BLOCK_GROUP_bf_create (cls,
bf_size,
BLOOMFILTER_K,
type,
nonce,
raw_data,
raw_data_size);
}
/**
* Function called to validate a reply or a request. For
* request evaluation, simply pass "NULL" for the reply_block.
* Note that it is assumed that the reply has already been
* matched to the key (and signatures checked) as it would
* be done with the "get_key" function.
*
* @param cls closure
* @param ctx block context
* @param type block type
* @param bg block group to use for evaluation
* @param eo control flags
* @param query original query (hash)
* @param xquery extrended query data (can be NULL, depending on @a type)
* @param xquery_size number of bytes in @a xquery
* @param reply_block response to validate
* @param reply_block_size number of bytes in @a reply_block
* @return characterization of result
*/
static enum GNUNET_BLOCK_EvaluationResult
block_plugin_gns_evaluate (void *cls,
struct GNUNET_BLOCK_Context *ctx,
enum GNUNET_BLOCK_Type type,
struct GNUNET_BLOCK_Group *bg,
enum GNUNET_BLOCK_EvaluationOptions eo,
const struct GNUNET_HashCode *query,
const void *xquery,
size_t xquery_size,
const void *reply_block,
size_t reply_block_size)
{
const struct GNUNET_GNSRECORD_Block *block;
struct GNUNET_HashCode h;
struct GNUNET_HashCode chash;
if (type != GNUNET_BLOCK_TYPE_GNS_NAMERECORD)
return GNUNET_BLOCK_EVALUATION_TYPE_NOT_SUPPORTED;
if (NULL == reply_block)
{
if (0 != xquery_size)
{
GNUNET_break_op (0);
return GNUNET_BLOCK_EVALUATION_REQUEST_INVALID;
}
return GNUNET_BLOCK_EVALUATION_REQUEST_VALID;
}
/* this is a reply */
if (reply_block_size < sizeof (struct GNUNET_GNSRECORD_Block))
{
GNUNET_break_op (0);
return GNUNET_BLOCK_EVALUATION_RESULT_INVALID;
}
block = reply_block;
if (ntohl (block->purpose.size) + sizeof (struct GNUNET_CRYPTO_EcdsaSignature) + sizeof (struct GNUNET_CRYPTO_EcdsaPublicKey) !=
reply_block_size)
{
GNUNET_break_op (0);
return GNUNET_BLOCK_EVALUATION_RESULT_INVALID;
}
GNUNET_CRYPTO_hash (&block->derived_key,
sizeof (block->derived_key),
&h);
if (0 != memcmp (&h, query, sizeof (struct GNUNET_HashCode)))
{
GNUNET_break_op (0);
return GNUNET_BLOCK_EVALUATION_RESULT_INVALID;
}
if (GNUNET_OK !=
GNUNET_GNSRECORD_block_verify (block))
{
GNUNET_break_op (0);
return GNUNET_BLOCK_EVALUATION_RESULT_INVALID;
}
GNUNET_CRYPTO_hash (reply_block,
reply_block_size,
&chash);
if (GNUNET_YES ==
GNUNET_BLOCK_GROUP_bf_test_and_set (bg,
&chash))
return GNUNET_BLOCK_EVALUATION_OK_DUPLICATE;
return GNUNET_BLOCK_EVALUATION_OK_MORE;
}
/**
* Function called to obtain the key for a block.
*
* @param cls closure
* @param type block type
* @param reply_block block to get the key for
* @param reply_block_size number of bytes in @a reply_block
* @param key set to the key (query) for the given block
* @return #GNUNET_OK on success, #GNUNET_SYSERR if type not supported
* (or if extracting a key from a block of this type does not work)
*/
static int
block_plugin_gns_get_key (void *cls,
enum GNUNET_BLOCK_Type type,
const void *reply_block,
size_t reply_block_size,
struct GNUNET_HashCode *key)
{
const struct GNUNET_GNSRECORD_Block *block;
if (type != GNUNET_BLOCK_TYPE_GNS_NAMERECORD)
return GNUNET_SYSERR;
if (reply_block_size < sizeof (struct GNUNET_GNSRECORD_Block))
{
GNUNET_break_op (0);
return GNUNET_BLOCK_EVALUATION_RESULT_INVALID;
}
block = reply_block;
GNUNET_CRYPTO_hash (&block->derived_key,
sizeof (block->derived_key),
key);
return GNUNET_OK;
}
/**
* Entry point for the plugin.
*/
void *
libgnunet_plugin_block_gns_init (void *cls)
{
static enum GNUNET_BLOCK_Type types[] =
{
GNUNET_BLOCK_TYPE_GNS_NAMERECORD,
GNUNET_BLOCK_TYPE_ANY /* end of list */
};
struct GNUNET_BLOCK_PluginFunctions *api;
api = GNUNET_new (struct GNUNET_BLOCK_PluginFunctions);
api->evaluate = &block_plugin_gns_evaluate;
api->get_key = &block_plugin_gns_get_key;
api->create_group = &block_plugin_gns_create_group;
api->types = types;
return api;
}
/**
* Exit point from the plugin.
*/
void *
libgnunet_plugin_block_gns_done (void *cls)
{
struct GNUNET_BLOCK_PluginFunctions *api = cls;
GNUNET_free (api);
return NULL;
}
/* end of plugin_block_gns.c */
|
