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23 * @file gns/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 GNUNET_HashCode our_zone;
67 static struct GNUNET_CRYPTO_RsaPrivateKey *our_key;
70 * Reply to dns request with the result from our lookup.
72 * @param cls the closure to the request (an InterceptLookupHandle)
73 * @param rh the request handle of the lookup
74 * @param rd_count the number of records to return
75 * @param rd the record data
78 reply_to_dns(void* cls, uint32_t rd_count,
79 const struct GNUNET_NAMESTORE_RecordData *rd)
85 struct InterceptLookupHandle* ilh = (struct InterceptLookupHandle*)cls;
86 struct GNUNET_DNSPARSER_Packet *packet = ilh->packet;
87 unsigned int num_answers = 0;
91 * Put records in the DNS packet and modify it
94 for (i=0; i < rd_count; i++)
96 if (rd[i].record_type == ilh->query->type)
100 struct GNUNET_DNSPARSER_Record answer_records[num_answers];
101 struct GNUNET_DNSPARSER_Record additional_records[rd_count-(num_answers)];
102 packet->answers = answer_records;
103 packet->additional_records = additional_records;
105 for (i=0; i < rd_count; i++)
107 GNUNET_log(GNUNET_ERROR_TYPE_DEBUG,
108 "Adding type %d to DNS response\n", rd[i].record_type);
109 GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "Name: %s\n", ilh->query->name);
110 GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "Record %d/%d\n", i+1, rd_count);
111 GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "Record len %d\n", rd[i].data_size);
113 if (rd[i].record_type == ilh->query->type)
115 answer_records[i].name = ilh->query->name;
116 answer_records[i].type = rd[i].record_type;
117 switch(rd[i].record_type)
119 case GNUNET_GNS_RECORD_TYPE_NS:
120 case GNUNET_GNS_RECORD_TYPE_CNAME:
121 case GNUNET_GNS_RECORD_TYPE_PTR:
122 answer_records[i].data.hostname = (char*)rd[i].data;
124 case GNUNET_GNS_RECORD_TYPE_SOA:
125 answer_records[i].data.soa =
126 (struct GNUNET_DNSPARSER_SoaRecord *)rd[i].data;
128 case GNUNET_GNS_RECORD_MX:
129 answer_records[i].data.mx =
130 (struct GNUNET_DNSPARSER_MxRecord *)rd[i].data;
133 answer_records[i].data.raw.data_len = rd[i].data_size;
134 answer_records[i].data.raw.data = (char*)rd[i].data;
136 answer_records[i].expiration_time = rd[i].expiration;
137 answer_records[i].class = GNUNET_DNSPARSER_CLASS_INTERNET;//hmmn
141 additional_records[i].name = ilh->query->name;
142 additional_records[i].type = rd[i].record_type;
143 switch(rd[i].record_type)
145 case GNUNET_GNS_RECORD_TYPE_NS:
146 case GNUNET_GNS_RECORD_TYPE_CNAME:
147 case GNUNET_GNS_RECORD_TYPE_PTR:
148 additional_records[i].data.hostname = (char*)rd[i].data;
150 case GNUNET_GNS_RECORD_TYPE_SOA:
151 additional_records[i].data.soa =
152 (struct GNUNET_DNSPARSER_SoaRecord *)rd[i].data;
154 case GNUNET_GNS_RECORD_MX:
155 additional_records[i].data.mx =
156 (struct GNUNET_DNSPARSER_MxRecord *)rd[i].data;
159 additional_records[i].data.raw.data_len = rd[i].data_size;
160 additional_records[i].data.raw.data = (char*)rd[i].data;
162 additional_records[i].expiration_time = rd[i].expiration;
163 additional_records[i].class = GNUNET_DNSPARSER_CLASS_INTERNET;//hmmn
167 packet->num_answers = num_answers;
168 packet->num_additional_records = rd_count-(num_answers);
170 packet->flags.authoritative_answer = 1;
173 packet->flags.return_code = GNUNET_DNSPARSER_RETURN_CODE_NAME_ERROR;
175 packet->flags.return_code = GNUNET_DNSPARSER_RETURN_CODE_NO_ERROR;
177 packet->flags.query_or_response = 1;
183 GNUNET_log(GNUNET_ERROR_TYPE_DEBUG,
184 "Building DNS response\n");
185 ret = GNUNET_DNSPARSER_pack (packet,
186 1024, /* FIXME magic from dns redirector */
189 GNUNET_log(GNUNET_ERROR_TYPE_DEBUG,
190 "Built DNS response! (ret=%d,len=%d)\n", ret, len);
191 if (ret == GNUNET_OK)
193 GNUNET_log(GNUNET_ERROR_TYPE_DEBUG,
194 "Answering DNS request\n");
195 GNUNET_DNS_request_answer(ilh->request_handle,
200 GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "Answered DNS request\n");
204 GNUNET_log(GNUNET_ERROR_TYPE_ERROR,
205 "Error building DNS response! (ret=%d)", ret);
208 packet->num_answers = 0;
209 packet->answers = NULL;
210 packet->num_additional_records = 0;
211 packet->additional_records = NULL;
212 GNUNET_DNSPARSER_free_packet(packet);
218 * Entry point for name resolution
219 * Setup a new query and try to resolve
221 * @param request the request handle of the DNS request from a client
222 * @param p the DNS query packet we received
223 * @param q the DNS query we received parsed from p
226 start_resolution_for_dns(struct GNUNET_DNS_RequestHandle *request,
227 struct GNUNET_DNSPARSER_Packet *p,
228 struct GNUNET_DNSPARSER_Query *q)
230 struct InterceptLookupHandle* ilh;
232 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
233 "Starting resolution for %s (type=%d)!\n",
236 ilh = GNUNET_malloc(sizeof(struct InterceptLookupHandle));
239 ilh->request_handle = request;
241 /* Start resolution in our zone */
242 gns_resolver_lookup_record(our_zone, q->type, q->name,
250 * The DNS request handler
251 * Called for every incoming DNS request.
254 * @param rh request handle to user for reply
255 * @param request_length number of bytes in request
256 * @param request udp payload of the DNS request
259 handle_dns_request(void *cls,
260 struct GNUNET_DNS_RequestHandle *rh,
261 size_t request_length,
264 struct GNUNET_DNSPARSER_Packet *p;
266 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Hijacked a DNS request...processing\n");
267 p = GNUNET_DNSPARSER_parse (request, request_length);
271 GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
272 "Received malformed DNS packet, leaving it untouched\n");
273 GNUNET_DNS_request_forward (rh);
274 GNUNET_DNSPARSER_free_packet (p);
279 * Check tld and decide if we or
280 * legacy dns is responsible
282 * FIXME now in theory there could be more than 1 query in the request
283 * but if this is case we get into trouble:
284 * either we query the GNS or the DNS. We cannot do both!
285 * So I suggest to either only allow a single query per request or
286 * only allow GNS or DNS requests.
287 * The way it is implemented here now is buggy and will lead to erratic
288 * behaviour (if multiple queries are present).
290 if (p->num_queries == 0)
292 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
293 "No Queries in DNS packet... forwarding\n");
294 GNUNET_DNS_request_forward (rh);
295 GNUNET_DNSPARSER_free_packet(p);
299 if (p->num_queries > 1)
301 /* Note: We could also look for .gnunet */
302 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
303 ">1 queriy in DNS packet... odd. We only process #1\n");
308 * Check for .gnunet/.zkey
311 if ((is_gnunet_tld(p->queries[0].name) == GNUNET_YES) ||
312 (is_zkey_tld(p->queries[0].name) == GNUNET_YES))
314 start_resolution_for_dns(rh, p, p->queries);
319 * This request does not concern us. Forward to real DNS.
321 GNUNET_log(GNUNET_ERROR_TYPE_DEBUG,
322 "Request for %s is forwarded to DNS\n", p->queries[0].name);
323 GNUNET_DNS_request_forward (rh);
324 GNUNET_DNSPARSER_free_packet (p);
331 * Initialized the interceptor
333 * @param zone the zone to work in
334 * @param the prov key of the zone (can be null, needed for caching)
335 * @param c the configuration
336 * @return GNUNET_OK on success
339 gns_interceptor_init(GNUNET_HashCode zone,
340 struct GNUNET_CRYPTO_RsaPrivateKey *key,
341 const struct GNUNET_CONFIGURATION_Handle *c)
343 GNUNET_log(GNUNET_ERROR_TYPE_INFO,
344 "DNS hijacking enabled... connecting to service.\n");
349 * Do gnunet dns init here
351 dns_handle = GNUNET_DNS_connect(c,
352 GNUNET_DNS_FLAG_PRE_RESOLUTION,
353 &handle_dns_request, /* rh */
355 if (NULL == dns_handle)
357 GNUNET_log(GNUNET_ERROR_TYPE_ERROR,
358 "Failed to connect to the dnsservice!\n");
359 return GNUNET_SYSERR;
365 /* end of gns_interceptor.c */