2 This file is part of GNUnet.
3 (C) 2009, 2010, 2011 Christian Grothoff (and other contributing authors)
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6 it under the terms of the GNU General Public License as published
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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
44 * the request handle to reply to
46 struct GNUNET_DNS_RequestHandle *request_handle;
49 * the dns parser packet received
51 struct GNUNET_DNSPARSER_Packet *packet;
54 * the query parsed from the packet
56 struct GNUNET_DNSPARSER_Query *query;
61 * Our handle to the DNS handler library
63 static struct GNUNET_DNS_Handle *dns_handle;
66 * The root zone for this interceptor
68 static struct GNUNET_CRYPTO_ShortHashCode our_zone;
73 static struct GNUNET_CRYPTO_RsaPrivateKey *our_key;
78 static struct GNUNET_TIME_Relative default_lookup_timeout;
82 * Reply to dns request with the result from our lookup.
84 * @param cls the closure to the request (an InterceptLookupHandle)
85 * @param rd_count the number of records to return
86 * @param rd the record data
89 reply_to_dns(void* cls, uint32_t rd_count,
90 const struct GNUNET_NAMESTORE_RecordData *rd)
96 struct InterceptLookupHandle* ilh = (struct InterceptLookupHandle*)cls;
97 struct GNUNET_DNSPARSER_Packet *packet = ilh->packet;
98 unsigned int num_answers = 0;
102 * Put records in the DNS packet and modify it
105 for (i=0; i < rd_count; i++)
107 if (rd[i].record_type == ilh->query->type)
111 struct GNUNET_DNSPARSER_Record answer_records[num_answers];
112 struct GNUNET_DNSPARSER_Record additional_records[rd_count-(num_answers)];
113 packet->answers = answer_records;
114 packet->additional_records = additional_records;
116 for (i=0; i < rd_count; i++)
118 GNUNET_log(GNUNET_ERROR_TYPE_DEBUG,
119 "Adding type %d to DNS response\n", rd[i].record_type);
120 GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "Name: %s\n", ilh->query->name);
121 GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "Record %d/%d\n", i+1, rd_count);
122 GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "Record len %d\n", rd[i].data_size);
124 if (rd[i].record_type == ilh->query->type)
126 answer_records[i].name = ilh->query->name;
127 answer_records[i].type = rd[i].record_type;
128 switch(rd[i].record_type)
130 case GNUNET_GNS_RECORD_NS:
131 case GNUNET_GNS_RECORD_CNAME:
132 case GNUNET_GNS_RECORD_PTR:
133 answer_records[i].data.hostname = (char*)rd[i].data;
135 case GNUNET_GNS_RECORD_SOA:
136 answer_records[i].data.soa =
137 (struct GNUNET_DNSPARSER_SoaRecord *)rd[i].data;
139 case GNUNET_GNS_RECORD_MX:
140 answer_records[i].data.mx =
141 (struct GNUNET_DNSPARSER_MxRecord *)rd[i].data;
144 answer_records[i].data.raw.data_len = rd[i].data_size;
145 answer_records[i].data.raw.data = (char*)rd[i].data;
147 GNUNET_break (0 == (rd[i].flags & GNUNET_NAMESTORE_RF_RELATIVE_EXPIRATION));
148 answer_records[i].expiration_time.abs_value = rd[i].expiration_time;
149 answer_records[i].class = GNUNET_DNSPARSER_CLASS_INTERNET;//hmmn
153 additional_records[i].name = ilh->query->name;
154 additional_records[i].type = rd[i].record_type;
155 switch(rd[i].record_type)
157 case GNUNET_GNS_RECORD_NS:
158 case GNUNET_GNS_RECORD_CNAME:
159 case GNUNET_GNS_RECORD_PTR:
160 additional_records[i].data.hostname = (char*)rd[i].data;
162 case GNUNET_GNS_RECORD_SOA:
163 additional_records[i].data.soa =
164 (struct GNUNET_DNSPARSER_SoaRecord *)rd[i].data;
166 case GNUNET_GNS_RECORD_MX:
167 additional_records[i].data.mx =
168 (struct GNUNET_DNSPARSER_MxRecord *)rd[i].data;
171 additional_records[i].data.raw.data_len = rd[i].data_size;
172 additional_records[i].data.raw.data = (char*)rd[i].data;
174 GNUNET_break (0 == (rd[i].flags & GNUNET_NAMESTORE_RF_RELATIVE_EXPIRATION));
175 additional_records[i].expiration_time.abs_value = rd[i].expiration_time;
176 additional_records[i].class = GNUNET_DNSPARSER_CLASS_INTERNET;//hmmn
180 packet->num_answers = num_answers;
181 packet->num_additional_records = rd_count-(num_answers);
183 packet->flags.authoritative_answer = 1;
186 packet->flags.return_code = GNUNET_DNSPARSER_RETURN_CODE_NAME_ERROR;
188 packet->flags.return_code = GNUNET_DNSPARSER_RETURN_CODE_NO_ERROR;
190 packet->flags.query_or_response = 1;
196 GNUNET_log(GNUNET_ERROR_TYPE_DEBUG,
197 "Building DNS response\n");
198 ret = GNUNET_DNSPARSER_pack (packet,
199 1024, /* FIXME magic from dns redirector */
202 GNUNET_log(GNUNET_ERROR_TYPE_DEBUG,
203 "Built DNS response! (ret=%d,len=%d)\n", ret, len);
204 if (ret == GNUNET_OK)
206 GNUNET_log(GNUNET_ERROR_TYPE_DEBUG,
207 "Answering DNS request\n");
208 GNUNET_DNS_request_answer(ilh->request_handle,
213 GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "Answered DNS request\n");
217 GNUNET_log(GNUNET_ERROR_TYPE_ERROR,
218 "Error building DNS response! (ret=%d)", ret);
221 packet->num_answers = 0;
222 packet->answers = NULL;
223 packet->num_additional_records = 0;
224 packet->additional_records = NULL;
225 GNUNET_DNSPARSER_free_packet(packet);
231 * Entry point for name resolution
232 * Setup a new query and try to resolve
234 * @param request the request handle of the DNS request from a client
235 * @param p the DNS query packet we received
236 * @param q the DNS query we received parsed from p
239 start_resolution_for_dns(struct GNUNET_DNS_RequestHandle *request,
240 struct GNUNET_DNSPARSER_Packet *p,
241 struct GNUNET_DNSPARSER_Query *q)
243 struct InterceptLookupHandle* ilh;
245 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
246 "Starting resolution for %s (type=%d)!\n",
249 ilh = GNUNET_malloc(sizeof(struct InterceptLookupHandle));
252 ilh->request_handle = request;
254 /* Start resolution in our zone */
255 gns_resolver_lookup_record(our_zone, our_zone, q->type, q->name,
257 default_lookup_timeout,
265 * The DNS request handler
266 * Called for every incoming DNS request.
269 * @param rh request handle to user for reply
270 * @param request_length number of bytes in request
271 * @param request udp payload of the DNS request
274 handle_dns_request(void *cls,
275 struct GNUNET_DNS_RequestHandle *rh,
276 size_t request_length,
279 struct GNUNET_DNSPARSER_Packet *p;
281 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Hijacked a DNS request...processing\n");
282 p = GNUNET_DNSPARSER_parse (request, request_length);
286 GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
287 "Received malformed DNS packet, leaving it untouched\n");
288 GNUNET_DNS_request_forward (rh);
289 GNUNET_DNSPARSER_free_packet (p);
294 * Check tld and decide if we or
295 * legacy dns is responsible
297 * FIXME now in theory there could be more than 1 query in the request
298 * but if this is case we get into trouble:
299 * either we query the GNS or the DNS. We cannot do both!
300 * So I suggest to either only allow a single query per request or
301 * only allow GNS or DNS requests.
302 * The way it is implemented here now is buggy and will lead to erratic
303 * behaviour (if multiple queries are present).
305 if (p->num_queries == 0)
307 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
308 "No Queries in DNS packet... forwarding\n");
309 GNUNET_DNS_request_forward (rh);
310 GNUNET_DNSPARSER_free_packet(p);
314 if (p->num_queries > 1)
316 /* Note: We could also look for .gnunet */
317 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
318 ">1 queriy in DNS packet... odd. We only process #1\n");
323 * Check for .gnunet/.zkey
326 if ((is_gnunet_tld(p->queries[0].name) == GNUNET_YES) ||
327 (is_zkey_tld(p->queries[0].name) == GNUNET_YES) ||
328 (strcmp(p->queries[0].name, GNUNET_GNS_TLD) == 0))
330 start_resolution_for_dns(rh, p, p->queries);
335 * This request does not concern us. Forward to real DNS.
337 GNUNET_log(GNUNET_ERROR_TYPE_DEBUG,
338 "Request for %s is forwarded to DNS\n", p->queries[0].name);
339 GNUNET_DNS_request_forward (rh);
340 GNUNET_DNSPARSER_free_packet (p);
347 * Initialized the interceptor
349 * @param zone the zone to work in
350 * @param key the prov key of the zone (can be null, needed for caching)
351 * @param c the configuration
352 * @return GNUNET_OK on success
355 gns_interceptor_init(struct GNUNET_CRYPTO_ShortHashCode zone,
356 struct GNUNET_CRYPTO_RsaPrivateKey *key,
357 const struct GNUNET_CONFIGURATION_Handle *c)
359 unsigned long long default_lookup_timeout_secs = 0;
361 GNUNET_log(GNUNET_ERROR_TYPE_INFO,
362 "DNS hijacking enabled... connecting to service.\n");
367 * Do gnunet dns init here
369 dns_handle = GNUNET_DNS_connect(c,
370 GNUNET_DNS_FLAG_PRE_RESOLUTION,
371 &handle_dns_request, /* rh */
375 GNUNET_CONFIGURATION_get_value_number(c, "gns",
376 "DEFAULT_LOOKUP_TIMEOUT",
377 &default_lookup_timeout_secs))
379 default_lookup_timeout = GNUNET_TIME_relative_multiply(
380 GNUNET_TIME_UNIT_SECONDS,
381 default_lookup_timeout_secs);
384 if (NULL == dns_handle)
386 GNUNET_log(GNUNET_ERROR_TYPE_ERROR,
387 "Failed to connect to the dnsservice!\n");
388 return GNUNET_SYSERR;
395 * Disconnect from interceptor
398 gns_interceptor_stop(void)
401 GNUNET_DNS_disconnect(dns_handle);
404 /* end of gns_interceptor.c */