GNUnet  0.11.x
plugin_block_dns.c
Go to the documentation of this file.
1 /*
2  This file is part of GNUnet
3  Copyright (C) 2013, 2017 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 
30 #include "platform.h"
31 #include "gnunet_block_plugin.h"
32 #include "block_dns.h"
33 #include "gnunet_signatures.h"
34 #include "gnunet_block_group_lib.h"
35 
36 
41 #define BLOOMFILTER_K 16
42 
43 
56 static struct GNUNET_BLOCK_Group *
59  uint32_t nonce,
60  const void *raw_data,
61  size_t raw_data_size,
62  va_list va)
63 {
64  unsigned int bf_size;
65  const char *guard;
66 
67  guard = va_arg (va, const char *);
68  if (0 == strcmp (guard,
69  "seen-set-size"))
70  bf_size = GNUNET_BLOCK_GROUP_compute_bloomfilter_size (va_arg (va, unsigned
71  int),
73  else if (0 == strcmp (guard,
74  "filter-size"))
75  bf_size = va_arg (va, unsigned int);
76  else
77  {
78  GNUNET_break (0);
79  bf_size = 8;
80  }
81  GNUNET_break (NULL == va_arg (va, const char *));
82  return GNUNET_BLOCK_GROUP_bf_create (cls,
83  bf_size,
85  type,
86  nonce,
87  raw_data,
88  raw_data_size);
89 }
90 
91 
110  struct GNUNET_BLOCK_Context *ctx,
111  enum GNUNET_BLOCK_Type type,
112  struct GNUNET_BLOCK_Group *bg,
114  const struct GNUNET_HashCode *query,
115  const void *xquery,
116  size_t xquery_size,
117  const void *reply_block,
118  size_t reply_block_size)
119 {
120  const struct GNUNET_DNS_Advertisement *ad;
121  struct GNUNET_HashCode phash;
122 
123  switch (type)
124  {
126  if (0 != xquery_size)
128 
129  if (NULL == reply_block)
131 
132  if (sizeof(struct GNUNET_DNS_Advertisement) != reply_block_size)
133  {
134  GNUNET_break_op (0);
136  }
137  ad = reply_block;
138 
139  if (ntohl (ad->purpose.size) !=
140  sizeof(struct GNUNET_DNS_Advertisement)
141  - sizeof(struct GNUNET_CRYPTO_EddsaSignature))
142  {
143  GNUNET_break_op (0);
145  }
146  if (0 ==
148  (ad->expiration_time)).
149  rel_value_us)
150  {
152  "DNS advertisement has expired\n");
154  }
155  if (GNUNET_OK !=
157  &ad->purpose,
158  &ad->signature,
159  &ad->peer.public_key))
160  {
161  GNUNET_break_op (0);
163  }
164  GNUNET_CRYPTO_hash (reply_block,
165  reply_block_size,
166  &phash);
167  if (GNUNET_YES ==
169  &phash))
172 
173  default:
175  }
176 }
177 
178 
190 static int
192  enum GNUNET_BLOCK_Type type,
193  const void *block,
194  size_t block_size,
195  struct GNUNET_HashCode *key)
196 {
197  /* we cannot extract a key from a block of this type */
198  return GNUNET_SYSERR;
199 }
200 
201 
205 void *
207 {
208  static enum GNUNET_BLOCK_Type types[] = {
210  GNUNET_BLOCK_TYPE_ANY /* end of list */
211  };
212  struct GNUNET_BLOCK_PluginFunctions *api;
213 
218  api->types = types;
219  return api;
220 }
221 
222 
226 void *
228 {
229  struct GNUNET_BLOCK_PluginFunctions *api = cls;
230 
231  GNUNET_free (api);
232  return NULL;
233 }
234 
235 
236 /* end of plugin_block_dns.c */
Block does not match query (invalid result)
void * libgnunet_plugin_block_dns_init(void *cls)
Entry point for the plugin.
Handle to an initialized block library.
Definition: block.c:54
struct GNUNET_TIME_Absolute GNUNET_TIME_absolute_ntoh(struct GNUNET_TIME_AbsoluteNBO a)
Convert absolute time from network byte order.
Definition: time.c:673
This is the structure describing an DNS exit service.
Definition: block_dns.h:40
enum GNUNET_BLOCK_Type * types
0-terminated array of block types supported by this plugin.
static enum GNUNET_BLOCK_EvaluationResult block_plugin_dns_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)
Function called to validate a reply or a request.
Any type of block, used as a wildcard when searching.
static struct GNUNET_BLOCK_Group * block_plugin_dns_create_group(void *cls, enum GNUNET_BLOCK_Type type, uint32_t nonce, const void *raw_data, size_t raw_data_size, va_list va)
Create a new block group.
GNUNET_BLOCK_EvaluationFunction evaluate
Main function of a block plugin.
GNUNET_BLOCK_Type
Blocks in the datastore and the datacache must have a unique type.
#define GNUNET_SIGNATURE_PURPOSE_DNS_RECORD
Signature of an GNUNET_DNS_Advertisement.
struct GNUNET_BLOCK_Group * GNUNET_BLOCK_GROUP_bf_create(void *cls, size_t bf_size, unsigned int bf_k, enum GNUNET_BLOCK_Type type, uint32_t nonce, const void *raw_data, size_t raw_data_size)
Create a new block group that filters duplicates using a Bloom filter.
Definition: bg_bf.c:174
Each plugin is required to return a pointer to a struct of this type as the return value from its ent...
static int block_plugin_dns_get_key(void *cls, enum GNUNET_BLOCK_Type type, const void *block, size_t block_size, struct GNUNET_HashCode *key)
Function called to obtain the key for a block.
#define GNUNET_OK
Named constants for return values.
Definition: gnunet_common.h:75
struct GNUNET_CRYPTO_EddsaSignature signature
Signature of the peer affirming that it is offering the service.
Definition: block_dns.h:45
#define GNUNET_new(type)
Allocate a struct or union of the given type.
struct GNUNET_CRYPTO_EccSignaturePurpose purpose
Beginning of signed portion of the record, signs everything until the end of the struct.
Definition: block_dns.h:51
size_t GNUNET_BLOCK_GROUP_compute_bloomfilter_size(unsigned int entry_count, unsigned int k)
How many bytes should a bloomfilter be if we have already seen entry_count responses? Sized so that do not have to re-size the filter too often (to keep it cheap).
Definition: bg_bf.c:250
#define GNUNET_break(cond)
Use this for internal assertion violations that are not fatal (can be handled) but should not occur...
static struct GNUNET_DNSSTUB_Context * ctx
Context for DNS resolution.
Block for storing DNS exit service advertisements.
int GNUNET_CRYPTO_eddsa_verify(uint32_t purpose, const struct GNUNET_CRYPTO_EccSignaturePurpose *validate, const struct GNUNET_CRYPTO_EddsaSignature *sig, const struct GNUNET_CRYPTO_EddsaPublicKey *pub)
Verify EdDSA signature.
Definition: crypto_ecc.c:1113
Valid result, but suppressed because it is a duplicate.
#define GNUNET_break_op(cond)
Use this for assertion violations caused by other peers (i.e.
void GNUNET_CRYPTO_hash(const void *block, size_t size, struct GNUNET_HashCode *ret)
Compute hash of a given block.
Definition: crypto_hash.c:48
void * libgnunet_plugin_block_dns_done(void *cls)
Exit point from the plugin.
uint32_t size
How many bytes does this signature sign? (including this purpose header); in network byte order (!)...
A 512-bit hashcode.
#define BLOOMFILTER_K
Number of bits we set per entry in the bloomfilter.
struct GNUNET_PeerIdentity peer
The peer providing this service.
Definition: block_dns.h:61
Valid result, and there may be more.
struct GNUNET_HashCode key
The key used in the DHT.
#define GNUNET_SYSERR
Definition: gnunet_common.h:76
GNUNET_BLOCK_GroupCreateFunction create_group
Create a block group to process a bunch of blocks in a shared context (i.e.
GNUNET_BLOCK_EvaluationResult
Possible ways for how a block may relate to a query.
an ECC signature using EdDSA.
Specified block type not supported by this plugin.
GNUNET_BLOCK_GetKeyFunction get_key
Obtain the key for a given block (if possible).
Query format does not match block type (invalid query).
#define GNUNET_log(kind,...)
Block group data.
struct GNUNET_TIME_Relative GNUNET_TIME_absolute_get_remaining(struct GNUNET_TIME_Absolute future)
Given a timestamp in the future, how much time remains until then?
Definition: time.c:331
enum GNUNET_TESTBED_UnderlayLinkModelType type
the type of this model
#define GNUNET_YES
Definition: gnunet_common.h:77
struct GNUNET_TIME_AbsoluteNBO expiration_time
When does this signature expire?
Definition: block_dns.h:56
int GNUNET_BLOCK_GROUP_bf_test_and_set(struct GNUNET_BLOCK_Group *bg, const struct GNUNET_HashCode *hc)
Test if hc is contained in the Bloom filter of bg.
Definition: bg_bf.c:214
void * cls
Closure for all of the callbacks.
GNUNET_BLOCK_EvaluationOptions
Flags that can be set to control the evaluation.
Query is valid, no reply given.
#define GNUNET_free(ptr)
Wrapper around free.
struct GNUNET_CRYPTO_EddsaPublicKey public_key