2 This file is part of GNUnet.
3 (C) 2009, 2010, 2011 Christian Grothoff (and other contributing authors)
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13 General Public License for more details.
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23 * @file gns/gnunet-service-gns_interceptor.c
24 * @brief GNUnet GNS interceptor logic
25 * @author Martin Schanzenbach
28 #include "gnunet_util_lib.h"
29 #include "gnunet_transport_service.h"
30 #include "gnunet_dns_service.h"
31 #include "gnunet_dnsparser_lib.h"
32 #include "gnunet-service-gns_resolver.h"
35 #define MAX_DNS_LABEL_LENGTH 63
38 * Handle to a DNS intercepted
41 struct InterceptLookupHandle
43 /* the request handle to reply to */
44 struct GNUNET_DNS_RequestHandle *request_handle;
46 /* the dns parser packet received */
47 struct GNUNET_DNSPARSER_Packet *packet;
49 /* the query parsed from the packet */
50 struct GNUNET_DNSPARSER_Query *query;
55 * Our handle to the DNS handler library
57 static struct GNUNET_DNS_Handle *dns_handle;
60 * The root zone for this interceptor
62 static struct GNUNET_CRYPTO_ShortHashCode our_zone;
67 static struct GNUNET_CRYPTO_RsaPrivateKey *our_key;
72 static struct GNUNET_TIME_Relative default_lookup_timeout;
75 * Reply to dns request with the result from our lookup.
77 * @param cls the closure to the request (an InterceptLookupHandle)
78 * @param rd_count the number of records to return
79 * @param rd the record data
82 reply_to_dns(void* cls, uint32_t rd_count,
83 const struct GNUNET_NAMESTORE_RecordData *rd)
89 struct InterceptLookupHandle* ilh = (struct InterceptLookupHandle*)cls;
90 struct GNUNET_DNSPARSER_Packet *packet = ilh->packet;
91 unsigned int num_answers = 0;
95 * Put records in the DNS packet and modify it
98 for (i=0; i < rd_count; i++)
100 if (rd[i].record_type == ilh->query->type)
104 struct GNUNET_DNSPARSER_Record answer_records[num_answers];
105 struct GNUNET_DNSPARSER_Record additional_records[rd_count-(num_answers)];
106 packet->answers = answer_records;
107 packet->additional_records = additional_records;
109 for (i=0; i < rd_count; i++)
111 GNUNET_log(GNUNET_ERROR_TYPE_DEBUG,
112 "Adding type %d to DNS response\n", rd[i].record_type);
113 GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "Name: %s\n", ilh->query->name);
114 GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "Record %d/%d\n", i+1, rd_count);
115 GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "Record len %d\n", rd[i].data_size);
117 if (rd[i].record_type == ilh->query->type)
119 answer_records[i].name = ilh->query->name;
120 answer_records[i].type = rd[i].record_type;
121 switch(rd[i].record_type)
123 case GNUNET_GNS_RECORD_TYPE_NS:
124 case GNUNET_GNS_RECORD_TYPE_CNAME:
125 case GNUNET_GNS_RECORD_TYPE_PTR:
126 answer_records[i].data.hostname = (char*)rd[i].data;
128 case GNUNET_GNS_RECORD_TYPE_SOA:
129 answer_records[i].data.soa =
130 (struct GNUNET_DNSPARSER_SoaRecord *)rd[i].data;
132 case GNUNET_GNS_RECORD_MX:
133 answer_records[i].data.mx =
134 (struct GNUNET_DNSPARSER_MxRecord *)rd[i].data;
137 answer_records[i].data.raw.data_len = rd[i].data_size;
138 answer_records[i].data.raw.data = (char*)rd[i].data;
140 answer_records[i].expiration_time = rd[i].expiration;
141 answer_records[i].class = GNUNET_DNSPARSER_CLASS_INTERNET;//hmmn
145 additional_records[i].name = ilh->query->name;
146 additional_records[i].type = rd[i].record_type;
147 switch(rd[i].record_type)
149 case GNUNET_GNS_RECORD_TYPE_NS:
150 case GNUNET_GNS_RECORD_TYPE_CNAME:
151 case GNUNET_GNS_RECORD_TYPE_PTR:
152 additional_records[i].data.hostname = (char*)rd[i].data;
154 case GNUNET_GNS_RECORD_TYPE_SOA:
155 additional_records[i].data.soa =
156 (struct GNUNET_DNSPARSER_SoaRecord *)rd[i].data;
158 case GNUNET_GNS_RECORD_MX:
159 additional_records[i].data.mx =
160 (struct GNUNET_DNSPARSER_MxRecord *)rd[i].data;
163 additional_records[i].data.raw.data_len = rd[i].data_size;
164 additional_records[i].data.raw.data = (char*)rd[i].data;
166 additional_records[i].expiration_time = rd[i].expiration;
167 additional_records[i].class = GNUNET_DNSPARSER_CLASS_INTERNET;//hmmn
171 packet->num_answers = num_answers;
172 packet->num_additional_records = rd_count-(num_answers);
174 packet->flags.authoritative_answer = 1;
177 packet->flags.return_code = GNUNET_DNSPARSER_RETURN_CODE_NAME_ERROR;
179 packet->flags.return_code = GNUNET_DNSPARSER_RETURN_CODE_NO_ERROR;
181 packet->flags.query_or_response = 1;
187 GNUNET_log(GNUNET_ERROR_TYPE_DEBUG,
188 "Building DNS response\n");
189 ret = GNUNET_DNSPARSER_pack (packet,
190 1024, /* FIXME magic from dns redirector */
193 GNUNET_log(GNUNET_ERROR_TYPE_DEBUG,
194 "Built DNS response! (ret=%d,len=%d)\n", ret, len);
195 if (ret == GNUNET_OK)
197 GNUNET_log(GNUNET_ERROR_TYPE_DEBUG,
198 "Answering DNS request\n");
199 GNUNET_DNS_request_answer(ilh->request_handle,
204 GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "Answered DNS request\n");
208 GNUNET_log(GNUNET_ERROR_TYPE_ERROR,
209 "Error building DNS response! (ret=%d)", ret);
212 packet->num_answers = 0;
213 packet->answers = NULL;
214 packet->num_additional_records = 0;
215 packet->additional_records = NULL;
216 GNUNET_DNSPARSER_free_packet(packet);
222 * Entry point for name resolution
223 * Setup a new query and try to resolve
225 * @param request the request handle of the DNS request from a client
226 * @param p the DNS query packet we received
227 * @param q the DNS query we received parsed from p
230 start_resolution_for_dns(struct GNUNET_DNS_RequestHandle *request,
231 struct GNUNET_DNSPARSER_Packet *p,
232 struct GNUNET_DNSPARSER_Query *q)
234 struct InterceptLookupHandle* ilh;
236 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
237 "Starting resolution for %s (type=%d)!\n",
240 ilh = GNUNET_malloc(sizeof(struct InterceptLookupHandle));
243 ilh->request_handle = request;
245 /* Start resolution in our zone */
246 gns_resolver_lookup_record(our_zone, q->type, q->name,
248 default_lookup_timeout,
255 * The DNS request handler
256 * Called for every incoming DNS request.
259 * @param rh request handle to user for reply
260 * @param request_length number of bytes in request
261 * @param request udp payload of the DNS request
264 handle_dns_request(void *cls,
265 struct GNUNET_DNS_RequestHandle *rh,
266 size_t request_length,
269 struct GNUNET_DNSPARSER_Packet *p;
271 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Hijacked a DNS request...processing\n");
272 p = GNUNET_DNSPARSER_parse (request, request_length);
276 GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
277 "Received malformed DNS packet, leaving it untouched\n");
278 GNUNET_DNS_request_forward (rh);
279 GNUNET_DNSPARSER_free_packet (p);
284 * Check tld and decide if we or
285 * legacy dns is responsible
287 * FIXME now in theory there could be more than 1 query in the request
288 * but if this is case we get into trouble:
289 * either we query the GNS or the DNS. We cannot do both!
290 * So I suggest to either only allow a single query per request or
291 * only allow GNS or DNS requests.
292 * The way it is implemented here now is buggy and will lead to erratic
293 * behaviour (if multiple queries are present).
295 if (p->num_queries == 0)
297 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
298 "No Queries in DNS packet... forwarding\n");
299 GNUNET_DNS_request_forward (rh);
300 GNUNET_DNSPARSER_free_packet(p);
304 if (p->num_queries > 1)
306 /* Note: We could also look for .gnunet */
307 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
308 ">1 queriy in DNS packet... odd. We only process #1\n");
313 * Check for .gnunet/.zkey
316 if ((is_gnunet_tld(p->queries[0].name) == GNUNET_YES) ||
317 (is_zkey_tld(p->queries[0].name) == GNUNET_YES) ||
318 (strcmp(p->queries[0].name, GNUNET_GNS_TLD) == 0))
320 start_resolution_for_dns(rh, p, p->queries);
325 * This request does not concern us. Forward to real DNS.
327 GNUNET_log(GNUNET_ERROR_TYPE_DEBUG,
328 "Request for %s is forwarded to DNS\n", p->queries[0].name);
329 GNUNET_DNS_request_forward (rh);
330 GNUNET_DNSPARSER_free_packet (p);
337 * Initialized the interceptor
339 * @param zone the zone to work in
340 * @param key the prov key of the zone (can be null, needed for caching)
341 * @param c the configuration
342 * @return GNUNET_OK on success
345 gns_interceptor_init(struct GNUNET_CRYPTO_ShortHashCode zone,
346 struct GNUNET_CRYPTO_RsaPrivateKey *key,
347 const struct GNUNET_CONFIGURATION_Handle *c)
349 unsigned long long default_lookup_timeout_secs = 0;
351 GNUNET_log(GNUNET_ERROR_TYPE_INFO,
352 "DNS hijacking enabled... connecting to service.\n");
357 * Do gnunet dns init here
359 dns_handle = GNUNET_DNS_connect(c,
360 GNUNET_DNS_FLAG_PRE_RESOLUTION,
361 &handle_dns_request, /* rh */
365 GNUNET_CONFIGURATION_get_value_number(c, "gns",
366 "DEFAULT_LOOKUP_TIMEOUT",
367 &default_lookup_timeout_secs))
369 default_lookup_timeout = GNUNET_TIME_relative_multiply(
370 GNUNET_TIME_UNIT_SECONDS,
371 default_lookup_timeout_secs);
374 if (NULL == dns_handle)
376 GNUNET_log(GNUNET_ERROR_TYPE_ERROR,
377 "Failed to connect to the dnsservice!\n");
378 return GNUNET_SYSERR;
385 * Disconnect from interceptor
388 gns_interceptor_stop(void)
391 GNUNET_DNS_disconnect(dns_handle);
394 /* end of gns_interceptor.c */