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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 additional_records[i].data.raw.data_len = rd[i].data_size;
144 additional_records[i].data.raw.data = (char*)rd[i].data;
145 additional_records[i].expiration_time = rd[i].expiration;
146 additional_records[i].class = GNUNET_DNSPARSER_CLASS_INTERNET;//hmmn
150 packet->num_answers = num_answers;
151 packet->num_additional_records = rd_count-(num_answers);
153 packet->flags.authoritative_answer = 1;
156 packet->flags.return_code = GNUNET_DNSPARSER_RETURN_CODE_NAME_ERROR;
158 packet->flags.return_code = GNUNET_DNSPARSER_RETURN_CODE_NO_ERROR;
160 packet->flags.query_or_response = 1;
166 GNUNET_log(GNUNET_ERROR_TYPE_DEBUG,
167 "Building DNS response\n");
168 ret = GNUNET_DNSPARSER_pack (packet,
169 1024, /* FIXME magic from dns redirector */
172 GNUNET_log(GNUNET_ERROR_TYPE_DEBUG,
173 "Built DNS response! (ret=%d,len=%d)\n", ret, len);
174 if (ret == GNUNET_OK)
176 GNUNET_log(GNUNET_ERROR_TYPE_DEBUG,
177 "Answering DNS request\n");
178 GNUNET_DNS_request_answer(ilh->request_handle,
183 GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "Answered DNS request\n");
187 GNUNET_log(GNUNET_ERROR_TYPE_ERROR,
188 "Error building DNS response! (ret=%d)", ret);
191 packet->num_answers = 0;
192 packet->answers = NULL;
193 packet->num_additional_records = 0;
194 packet->additional_records = NULL;
195 GNUNET_DNSPARSER_free_packet(packet);
196 //FIXME free resolver handle in resp functions in resolver!
197 //GNUNET_free((struct RecordLookupHandle*)rh->proc_cls);
198 //free_resolver_handle(rh);
204 * Entry point for name resolution
205 * Setup a new query and try to resolve
207 * @param request the request handle of the DNS request from a client
208 * @param p the DNS query packet we received
209 * @param q the DNS query we received parsed from p
212 start_resolution_for_dns(struct GNUNET_DNS_RequestHandle *request,
213 struct GNUNET_DNSPARSER_Packet *p,
214 struct GNUNET_DNSPARSER_Query *q)
216 struct InterceptLookupHandle* ilh;
218 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
219 "Starting resolution for %s (type=%d)!\n",
222 ilh = GNUNET_malloc(sizeof(struct InterceptLookupHandle));
225 ilh->request_handle = request;
227 /* Start resolution in our zone */
228 gns_resolver_lookup_record(our_zone, q->type, q->name,
236 * The DNS request handler
237 * Called for every incoming DNS request.
240 * @param rh request handle to user for reply
241 * @param request_length number of bytes in request
242 * @param request udp payload of the DNS request
245 handle_dns_request(void *cls,
246 struct GNUNET_DNS_RequestHandle *rh,
247 size_t request_length,
250 struct GNUNET_DNSPARSER_Packet *p;
254 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Hijacked a DNS request...processing\n");
255 p = GNUNET_DNSPARSER_parse (request, request_length);
259 GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
260 "Received malformed DNS packet, leaving it untouched\n");
261 GNUNET_DNS_request_forward (rh);
262 GNUNET_DNSPARSER_free_packet (p);
267 * Check tld and decide if we or
268 * legacy dns is responsible
270 * FIXME now in theory there could be more than 1 query in the request
271 * but if this is case we get into trouble:
272 * either we query the GNS or the DNS. We cannot do both!
273 * So I suggest to either only allow a single query per request or
274 * only allow GNS or DNS requests.
275 * The way it is implemented here now is buggy and will lead to erratic
276 * behaviour (if multiple queries are present).
278 if (p->num_queries == 0)
280 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
281 "No Queries in DNS packet... forwarding\n");
282 GNUNET_DNS_request_forward (rh);
283 GNUNET_DNSPARSER_free_packet(p);
287 if (p->num_queries > 1)
289 /* Note: We could also look for .gnunet */
290 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
291 ">1 queriy in DNS packet... odd. We only process #1\n");
298 tldoffset = p->queries[0].name + strlen(p->queries[0].name) - 1;
300 for (i=0; i<strlen(p->queries[0].name); i++)
302 if (*(tldoffset-i) == '.')
308 if ((i==strlen(GNUNET_GNS_TLD)-1)
309 && (0 == strcmp(tldoffset-i, GNUNET_GNS_TLD)))
311 start_resolution_for_dns(rh, p, p->queries);
316 * This request does not concern us. Forward to real DNS.
318 GNUNET_log(GNUNET_ERROR_TYPE_DEBUG,
319 "Request for %s is forwarded to DNS\n", p->queries[0].name);
320 GNUNET_DNS_request_forward (rh);
321 GNUNET_DNSPARSER_free_packet (p);
328 * Initialized the interceptor
330 * @param zone the zone to work in
331 * @param the prov key of the zone (can be null, needed for caching)
332 * @param c the configuration
333 * @return GNUNET_OK on success
336 gns_interceptor_init(GNUNET_HashCode zone,
337 struct GNUNET_CRYPTO_RsaPrivateKey *key,
338 const struct GNUNET_CONFIGURATION_Handle *c)
340 GNUNET_log(GNUNET_ERROR_TYPE_INFO,
341 "DNS hijacking enabled... connecting to service.\n");
346 * Do gnunet dns init here
348 dns_handle = GNUNET_DNS_connect(c,
349 GNUNET_DNS_FLAG_PRE_RESOLUTION,
350 &handle_dns_request, /* rh */
352 if (NULL == dns_handle)
354 GNUNET_log(GNUNET_ERROR_TYPE_ERROR,
355 "Failed to connect to the dnsservice!\n");
356 return GNUNET_SYSERR;
362 /* end of gns_interceptor.c */