GNUnet 0.21.1
plugin_block_dns.c File Reference

block plugin for advertising a DNS exit service More...

#include "platform.h"
#include "gnunet_block_plugin.h"
#include "block_dns.h"
#include "gnunet_signatures.h"
#include "gnunet_block_group_lib.h"
Include dependency graph for plugin_block_dns.c:

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Macros

#define BLOOMFILTER_K   16
 Number of bits we set per entry in the bloomfilter. More...
 

Functions

static struct GNUNET_BLOCK_Groupblock_plugin_dns_create_group (void *cls, enum GNUNET_BLOCK_Type type, const void *raw_data, size_t raw_data_size, va_list va)
 Create a new block group. More...
 
static enum GNUNET_GenericReturnValue block_plugin_dns_check_query (void *cls, enum GNUNET_BLOCK_Type type, const struct GNUNET_HashCode *query, const void *xquery, size_t xquery_size)
 Function called to validate a query. More...
 
static enum GNUNET_GenericReturnValue block_plugin_dns_check_block (void *cls, enum GNUNET_BLOCK_Type type, const void *block, size_t block_size)
 Function called to validate a block for storage. More...
 
static enum GNUNET_BLOCK_ReplyEvaluationResult block_plugin_dns_check_reply (void *cls, enum GNUNET_BLOCK_Type type, struct GNUNET_BLOCK_Group *group, 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 to a request. More...
 
static enum GNUNET_GenericReturnValue 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. More...
 
void * libgnunet_plugin_block_dns_init (void *cls)
 Entry point for the plugin. More...
 
void * libgnunet_plugin_block_dns_done (void *cls)
 Exit point from the plugin. More...
 

Detailed Description

block plugin for advertising a DNS exit service

Author
Christian Grothoff

Note that this plugin might more belong with EXIT and PT as those two are using this type of block. Still, this might be a natural enough place for people to find the code...

Definition in file plugin_block_dns.c.

Macro Definition Documentation

◆ BLOOMFILTER_K

#define BLOOMFILTER_K   16

Number of bits we set per entry in the bloomfilter.

Do not change!

Definition at line 41 of file plugin_block_dns.c.

Function Documentation

◆ block_plugin_dns_create_group()

static struct GNUNET_BLOCK_Group * block_plugin_dns_create_group ( void *  cls,
enum GNUNET_BLOCK_Type  type,
const void *  raw_data,
size_t  raw_data_size,
va_list  va 
)
static

Create a new block group.

Parameters
ctxblock context in which the block group is created
typetype of the block for which we are creating the group
raw_dataoptional serialized prior state of the group, NULL if unavailable/fresh
raw_data_sizenumber of bytes in raw_data, 0 if unavailable/fresh
vavariable arguments specific to type
Returns
block group handle, NULL if block groups are not supported by this type of block (this is not an error)

Definition at line 56 of file plugin_block_dns.c.

61{
62 unsigned int bf_size;
63 const char *guard;
64
65 guard = va_arg (va, const char *);
66 if (0 == strcmp (guard,
67 "seen-set-size"))
68 bf_size = GNUNET_BLOCK_GROUP_compute_bloomfilter_size (va_arg (va, unsigned
69 int),
71 else if (0 == strcmp (guard,
72 "filter-size"))
73 bf_size = va_arg (va, unsigned int);
74 else
75 {
76 GNUNET_break (0);
77 bf_size = 8;
78 }
79 GNUNET_break (NULL == va_arg (va, const char *));
81 bf_size,
83 type,
84 raw_data,
85 raw_data_size);
86}
static uint32_t type
Type string converted to DNS type value.
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?...
Definition: bg_bf.c:268
struct GNUNET_BLOCK_Group * GNUNET_BLOCK_GROUP_bf_create(void *cls, size_t bf_size, unsigned int bf_k, enum GNUNET_BLOCK_Type type, 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:173
#define GNUNET_break(cond)
Use this for internal assertion violations that are not fatal (can be handled) but should not occur.
#define BLOOMFILTER_K
Number of bits we set per entry in the bloomfilter.

References BLOOMFILTER_K, GNUNET_BLOCK_GROUP_bf_create(), GNUNET_BLOCK_GROUP_compute_bloomfilter_size(), GNUNET_break, and type.

Referenced by libgnunet_plugin_block_dns_init().

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◆ block_plugin_dns_check_query()

static enum GNUNET_GenericReturnValue block_plugin_dns_check_query ( void *  cls,
enum GNUNET_BLOCK_Type  type,
const struct GNUNET_HashCode query,
const void *  xquery,
size_t  xquery_size 
)
static

Function called to validate a query.

Parameters
clsclosure
typeblock type
queryoriginal query (hash)
xqueryextrended query data (can be NULL, depending on type)
xquery_sizenumber of bytes in xquery
Returns
GNUNET_OK if the query is fine, GNUNET_NO if not

Definition at line 100 of file plugin_block_dns.c.

105{
106 switch (type)
107 {
109 if (0 != xquery_size)
110 {
111 GNUNET_break_op (0);
112 return GNUNET_NO;
113 }
114 return GNUNET_OK;
115 default:
116 GNUNET_break (0);
117 return GNUNET_SYSERR;
118 }
119}
@ GNUNET_OK
@ GNUNET_NO
@ GNUNET_SYSERR
#define GNUNET_break_op(cond)
Use this for assertion violations caused by other peers (i.e.
@ GNUNET_BLOCK_TYPE_DNS
Block for storing DNS exit service advertisements.

References GNUNET_BLOCK_TYPE_DNS, GNUNET_break, GNUNET_break_op, GNUNET_NO, GNUNET_OK, GNUNET_SYSERR, and type.

Referenced by libgnunet_plugin_block_dns_init().

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◆ block_plugin_dns_check_block()

static enum GNUNET_GenericReturnValue block_plugin_dns_check_block ( void *  cls,
enum GNUNET_BLOCK_Type  type,
const void *  block,
size_t  block_size 
)
static

Function called to validate a block for storage.

Parameters
clsclosure
typeblock type
blockblock data to validate
block_sizenumber of bytes in block
Returns
GNUNET_OK if the block is fine, GNUNET_NO if not

Definition at line 132 of file plugin_block_dns.c.

136{
137 const struct GNUNET_DNS_Advertisement *ad;
138
139 switch (type)
140 {
142 if (sizeof(struct GNUNET_DNS_Advertisement) != block_size)
143 {
144 GNUNET_break_op (0);
145 return GNUNET_NO;
146 }
147 ad = block;
148
149 if (ntohl (ad->purpose.size) !=
150 sizeof(struct GNUNET_DNS_Advertisement)
151 - sizeof(struct GNUNET_CRYPTO_EddsaSignature))
152 {
153 GNUNET_break_op (0);
154 return GNUNET_NO;
155 }
158 {
160 "DNS advertisement has expired\n");
161 return GNUNET_NO;
162 }
163 if (GNUNET_OK !=
165 &ad->purpose,
166 &ad->signature,
167 &ad->peer.public_key))
168 {
169 GNUNET_break_op (0);
170 return GNUNET_NO;
171 }
172 return GNUNET_OK;
173 default:
174 GNUNET_break (0);
175 return GNUNET_SYSERR;
176 }
177}
enum GNUNET_GenericReturnValue 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:705
#define GNUNET_log(kind,...)
@ GNUNET_ERROR_TYPE_DEBUG
struct GNUNET_TIME_Absolute GNUNET_TIME_absolute_ntoh(struct GNUNET_TIME_AbsoluteNBO a)
Convert absolute time from network byte order.
Definition: time.c:737
bool GNUNET_TIME_absolute_is_past(struct GNUNET_TIME_Absolute abs)
Test if abs is truly in the past (excluding now).
Definition: time.c:669
#define GNUNET_SIGNATURE_PURPOSE_DNS_RECORD
Signature on a GNUNET_DNS_Advertisement.
uint32_t size
How many bytes does this signature sign? (including this purpose header); in network byte order (!...
an ECC signature using EdDSA.
This is the structure describing an DNS exit service.
Definition: block_dns.h:45
struct GNUNET_PeerIdentity peer
The peer providing this service.
Definition: block_dns.h:65
struct GNUNET_TIME_AbsoluteNBO expiration_time
When does this signature expire?
Definition: block_dns.h:60
struct GNUNET_CRYPTO_EddsaSignature signature
Signature of the peer affirming that it is offering the service.
Definition: block_dns.h:49
struct GNUNET_CRYPTO_EccSignaturePurpose purpose
Beginning of signed portion of the record, signs everything until the end of the struct.
Definition: block_dns.h:55
struct GNUNET_CRYPTO_EddsaPublicKey public_key

References GNUNET_DNS_Advertisement::expiration_time, GNUNET_BLOCK_TYPE_DNS, GNUNET_break, GNUNET_break_op, GNUNET_CRYPTO_eddsa_verify_(), GNUNET_ERROR_TYPE_DEBUG, GNUNET_log, GNUNET_NO, GNUNET_OK, GNUNET_SIGNATURE_PURPOSE_DNS_RECORD, GNUNET_SYSERR, GNUNET_TIME_absolute_is_past(), GNUNET_TIME_absolute_ntoh(), GNUNET_DNS_Advertisement::peer, GNUNET_PeerIdentity::public_key, GNUNET_DNS_Advertisement::purpose, GNUNET_DNS_Advertisement::signature, GNUNET_CRYPTO_EccSignaturePurpose::size, and type.

Referenced by libgnunet_plugin_block_dns_init().

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◆ block_plugin_dns_check_reply()

static enum GNUNET_BLOCK_ReplyEvaluationResult block_plugin_dns_check_reply ( void *  cls,
enum GNUNET_BLOCK_Type  type,
struct GNUNET_BLOCK_Group group,
const struct GNUNET_HashCode query,
const void *  xquery,
size_t  xquery_size,
const void *  reply_block,
size_t  reply_block_size 
)
static

Function called to validate a reply to a request.

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 GetKeyFunction and the BlockEvaluationFunction.

Parameters
clsclosure
typeblock type
groupwhich block group to use for evaluation
queryoriginal query (hash)
xqueryextrended query data (can be NULL, depending on type)
xquery_sizenumber of bytes in xquery
reply_blockresponse to validate
reply_block_sizenumber of bytes in reply_block
Returns
characterization of result

Definition at line 197 of file plugin_block_dns.c.

206{
207 struct GNUNET_HashCode phash;
208
209 switch (type)
210 {
212 GNUNET_CRYPTO_hash (reply_block,
213 reply_block_size,
214 &phash);
215 if (GNUNET_YES ==
217 &phash))
220 default:
221 GNUNET_break (0);
223 }
224}
enum GNUNET_GenericReturnValue 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:232
@ GNUNET_BLOCK_REPLY_OK_MORE
Valid result, and there may be more.
@ GNUNET_BLOCK_REPLY_OK_DUPLICATE
Valid result, but suppressed because it is a duplicate.
@ GNUNET_BLOCK_REPLY_TYPE_NOT_SUPPORTED
Specified block type not supported by any plugin.
void GNUNET_CRYPTO_hash(const void *block, size_t size, struct GNUNET_HashCode *ret)
Compute hash of a given block.
Definition: crypto_hash.c:41
@ GNUNET_YES
A 512-bit hashcode.

References GNUNET_BLOCK_GROUP_bf_test_and_set(), GNUNET_BLOCK_REPLY_OK_DUPLICATE, GNUNET_BLOCK_REPLY_OK_MORE, GNUNET_BLOCK_REPLY_TYPE_NOT_SUPPORTED, GNUNET_BLOCK_TYPE_DNS, GNUNET_break, GNUNET_CRYPTO_hash(), GNUNET_YES, and type.

Referenced by libgnunet_plugin_block_dns_init().

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◆ block_plugin_dns_get_key()

static enum GNUNET_GenericReturnValue block_plugin_dns_get_key ( void *  cls,
enum GNUNET_BLOCK_Type  type,
const void *  block,
size_t  block_size,
struct GNUNET_HashCode key 
)
static

Function called to obtain the key for a block.

Parameters
clsclosure
typeblock type
blockblock to get the key for
block_sizenumber of bytes in block
keyset to the key (query) for the given block
Returns
GNUNET_OK on success, GNUNET_SYSERR if type not supported (or if extracting a key from a block of this type does not work)

Definition at line 239 of file plugin_block_dns.c.

244{
246 {
247 GNUNET_break (0);
248 return GNUNET_SYSERR;
249 }
250 return GNUNET_NO;
251}

References GNUNET_BLOCK_TYPE_DNS, GNUNET_break, GNUNET_NO, GNUNET_SYSERR, and type.

Referenced by libgnunet_plugin_block_dns_init().

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◆ libgnunet_plugin_block_dns_init()

void * libgnunet_plugin_block_dns_init ( void *  cls)

Entry point for the plugin.

Definition at line 258 of file plugin_block_dns.c.

259{
260 static enum GNUNET_BLOCK_Type types[] = {
262 GNUNET_BLOCK_TYPE_ANY /* end of list */
263 };
265
272 api->types = types;
273 return api;
274}
#define GNUNET_new(type)
Allocate a struct or union of the given type.
static enum GNUNET_BLOCK_ReplyEvaluationResult block_plugin_dns_check_reply(void *cls, enum GNUNET_BLOCK_Type type, struct GNUNET_BLOCK_Group *group, 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 to a request.
static enum GNUNET_GenericReturnValue block_plugin_dns_check_block(void *cls, enum GNUNET_BLOCK_Type type, const void *block, size_t block_size)
Function called to validate a block for storage.
static enum GNUNET_GenericReturnValue block_plugin_dns_check_query(void *cls, enum GNUNET_BLOCK_Type type, const struct GNUNET_HashCode *query, const void *xquery, size_t xquery_size)
Function called to validate a query.
static enum GNUNET_GenericReturnValue 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.
static struct GNUNET_BLOCK_Group * block_plugin_dns_create_group(void *cls, enum GNUNET_BLOCK_Type type, const void *raw_data, size_t raw_data_size, va_list va)
Create a new block group.
GNUNET_BLOCK_Type
WARNING: This header is generated! In order to add DHT block types, you must register them in GANA,...
@ GNUNET_BLOCK_TYPE_ANY
Identifier for any block.
Each plugin is required to return a pointer to a struct of this type as the return value from its ent...
enum GNUNET_BLOCK_Type * types
0-terminated array of block types supported by this plugin.
GNUNET_BLOCK_QueryEvaluationFunction check_query
Check that a query is well-formed.
GNUNET_BLOCK_BlockEvaluationFunction check_block
Check that a block is well-formed.
GNUNET_BLOCK_GetKeyFunction get_key
Obtain the key for a given block (if possible).
GNUNET_BLOCK_ReplyEvaluationFunction check_reply
Check that a reply block matches a query.
GNUNET_BLOCK_GroupCreateFunction create_group
Create a block group to process a bunch of blocks in a shared context (i.e.

References block_plugin_dns_check_block(), block_plugin_dns_check_query(), block_plugin_dns_check_reply(), block_plugin_dns_create_group(), block_plugin_dns_get_key(), GNUNET_BLOCK_PluginFunctions::check_block, GNUNET_BLOCK_PluginFunctions::check_query, GNUNET_BLOCK_PluginFunctions::check_reply, GNUNET_BLOCK_PluginFunctions::create_group, GNUNET_BLOCK_PluginFunctions::get_key, GNUNET_BLOCK_TYPE_ANY, GNUNET_BLOCK_TYPE_DNS, GNUNET_new, and GNUNET_BLOCK_PluginFunctions::types.

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◆ libgnunet_plugin_block_dns_done()

void * libgnunet_plugin_block_dns_done ( void *  cls)

Exit point from the plugin.

Definition at line 281 of file plugin_block_dns.c.

282{
283 struct GNUNET_BLOCK_PluginFunctions *api = cls;
284
285 GNUNET_free (api);
286 return NULL;
287}
#define GNUNET_free(ptr)
Wrapper around free.
void * cls
Closure for all of the callbacks.

References GNUNET_BLOCK_PluginFunctions::cls, and GNUNET_free.