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3 (C) 2009, 2010, 2011 Christian Grothoff (and other contributing authors)
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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 struct GNUNET_DNS_Handle *dns_handle;
60 * The root zone for this interceptor
62 static GNUNET_HashCode our_zone;
65 * Reply to dns request with the result from our lookup.
67 * @param cls the closure to the request (an InterceptLookupHandle)
68 * @param rh the request handle of the lookup
69 * @param rd_count the number of records to return
70 * @param rd the record data
73 reply_to_dns(void* cls, uint32_t rd_count,
74 const struct GNUNET_NAMESTORE_RecordData *rd)
80 struct InterceptLookupHandle* ilh = (struct InterceptLookupHandle*)cls;
81 struct GNUNET_DNSPARSER_Packet *packet = ilh->packet;
82 unsigned int num_answers = 0;
86 * Put records in the DNS packet and modify it
89 for (i=0; i < rd_count; i++)
91 if (rd[i].record_type == ilh->query->type)
95 struct GNUNET_DNSPARSER_Record answer_records[num_answers];
96 struct GNUNET_DNSPARSER_Record additional_records[rd_count-(num_answers)];
97 packet->answers = answer_records;
98 packet->additional_records = additional_records;
100 for (i=0; i < rd_count; i++)
102 GNUNET_log(GNUNET_ERROR_TYPE_DEBUG,
103 "Adding type %d to DNS response\n", rd[i].record_type);
104 GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "Name: %s\n", ilh->query->name);
105 GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "Record %d/%d\n", i+1, rd_count);
106 GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "Record len %d\n", rd[i].data_size);
108 if (rd[i].record_type == ilh->query->type)
110 answer_records[i].name = ilh->query->name;
111 answer_records[i].type = rd[i].record_type;
112 answer_records[i].data.raw.data_len = rd[i].data_size;
113 answer_records[i].data.raw.data = (char*)rd[i].data;
114 answer_records[i].expiration_time = rd[i].expiration;
115 answer_records[i].class = GNUNET_DNSPARSER_CLASS_INTERNET;//hmmn
119 additional_records[i].name = ilh->query->name;
120 additional_records[i].type = rd[i].record_type;
121 additional_records[i].data.raw.data_len = rd[i].data_size;
122 additional_records[i].data.raw.data = (char*)rd[i].data;
123 additional_records[i].expiration_time = rd[i].expiration;
124 additional_records[i].class = GNUNET_DNSPARSER_CLASS_INTERNET;//hmmn
128 packet->num_answers = num_answers;
129 packet->num_additional_records = rd_count-(num_answers);
131 packet->flags.authoritative_answer = 1;
134 packet->flags.return_code = GNUNET_DNSPARSER_RETURN_CODE_NAME_ERROR;
136 packet->flags.return_code = GNUNET_DNSPARSER_RETURN_CODE_NO_ERROR;
138 packet->flags.query_or_response = 1;
144 GNUNET_log(GNUNET_ERROR_TYPE_DEBUG,
145 "Building DNS response\n");
146 ret = GNUNET_DNSPARSER_pack (packet,
147 1024, /* FIXME magic from dns redirector */
150 GNUNET_log(GNUNET_ERROR_TYPE_DEBUG,
151 "Built DNS response! (ret=%d,len=%d)\n", ret, len);
152 if (ret == GNUNET_OK)
154 GNUNET_log(GNUNET_ERROR_TYPE_DEBUG,
155 "Answering DNS request\n");
156 GNUNET_DNS_request_answer(ilh->request_handle,
161 GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "Answered DNS request\n");
165 GNUNET_log(GNUNET_ERROR_TYPE_ERROR,
166 "Error building DNS response! (ret=%d)", ret);
169 packet->num_answers = 0;
170 packet->answers = NULL;
171 packet->num_additional_records = 0;
172 packet->additional_records = NULL;
173 GNUNET_DNSPARSER_free_packet(packet);
174 //FIXME free resolver handle in resp functions in resolver!
175 //GNUNET_free((struct RecordLookupHandle*)rh->proc_cls);
176 //free_resolver_handle(rh);
182 * Entry point for name resolution
183 * Setup a new query and try to resolve
185 * @param request the request handle of the DNS request from a client
186 * @param p the DNS query packet we received
187 * @param q the DNS query we received parsed from p
190 start_resolution_for_dns(struct GNUNET_DNS_RequestHandle *request,
191 struct GNUNET_DNSPARSER_Packet *p,
192 struct GNUNET_DNSPARSER_Query *q)
194 struct InterceptLookupHandle* ilh;
196 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
197 "Starting resolution for %s (type=%d)!\n",
200 ilh = GNUNET_malloc(sizeof(struct InterceptLookupHandle));
203 ilh->request_handle = request;
205 /* Start resolution in our zone */
206 gns_resolver_lookup_record(our_zone, q->type, q->name, &reply_to_dns, ilh);
212 * The DNS request handler
213 * Called for every incoming DNS request.
216 * @param rh request handle to user for reply
217 * @param request_length number of bytes in request
218 * @param request udp payload of the DNS request
221 handle_dns_request(void *cls,
222 struct GNUNET_DNS_RequestHandle *rh,
223 size_t request_length,
226 struct GNUNET_DNSPARSER_Packet *p;
230 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Hijacked a DNS request...processing\n");
231 p = GNUNET_DNSPARSER_parse (request, request_length);
235 GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
236 "Received malformed DNS packet, leaving it untouched\n");
237 GNUNET_DNS_request_forward (rh);
238 GNUNET_DNSPARSER_free_packet (p);
243 * Check tld and decide if we or
244 * legacy dns is responsible
246 * FIXME now in theory there could be more than 1 query in the request
247 * but if this is case we get into trouble:
248 * either we query the GNS or the DNS. We cannot do both!
249 * So I suggest to either only allow a single query per request or
250 * only allow GNS or DNS requests.
251 * The way it is implemented here now is buggy and will lead to erratic
252 * behaviour (if multiple queries are present).
254 if (p->num_queries == 0)
256 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
257 "No Queries in DNS packet... forwarding\n");
258 GNUNET_DNS_request_forward (rh);
259 GNUNET_DNSPARSER_free_packet(p);
263 if (p->num_queries > 1)
265 /* Note: We could also look for .gnunet */
266 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
267 ">1 queriy in DNS packet... odd. We only process #1\n");
274 tldoffset = p->queries[0].name + strlen(p->queries[0].name) - 1;
276 for (i=0; i<strlen(p->queries[0].name); i++)
278 if (*(tldoffset-i) == '.')
284 if ((i==strlen(GNUNET_GNS_TLD)-1)
285 && (0 == strcmp(tldoffset-i, GNUNET_GNS_TLD)))
287 start_resolution_for_dns(rh, p, p->queries);
292 * This request does not concern us. Forward to real DNS.
294 GNUNET_log(GNUNET_ERROR_TYPE_DEBUG,
295 "Request for %s is forwarded to DNS\n", p->queries[0].name);
296 GNUNET_DNS_request_forward (rh);
297 GNUNET_DNSPARSER_free_packet (p);
304 gns_interceptor_init(GNUNET_HashCode zone,
305 const struct GNUNET_CONFIGURATION_Handle *c)
307 GNUNET_log(GNUNET_ERROR_TYPE_INFO,
308 "DNS hijacking enabled... connecting to service.\n");
312 * Do gnunet dns init here
314 dns_handle = GNUNET_DNS_connect(c,
315 GNUNET_DNS_FLAG_PRE_RESOLUTION,
316 &handle_dns_request, /* rh */
318 if (NULL == dns_handle)
320 GNUNET_log(GNUNET_ERROR_TYPE_ERROR,
321 "Failed to connect to the dnsservice!\n");
322 return GNUNET_SYSERR;
328 /* end of gns_interceptor.c */