/*
This file is part of GNUnet.
- (C) 2009, 2010, 2011 Christian Grothoff (and other contributing authors)
+ Copyright (C) 2009-2013 GNUnet e.V.
- GNUnet is free software; you can redistribute it and/or modify
- it under the terms of the GNU General Public License as published
- by the Free Software Foundation; either version 3, or (at your
- option) any later version.
+ GNUnet is free software: you can redistribute it and/or modify it
+ under the terms of the GNU Affero General Public License as published
+ by the Free Software Foundation, either version 3 of the License,
+ or (at your option) any later version.
GNUnet is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- General Public License for more details.
+ Affero General Public License for more details.
+
+ You should have received a copy of the GNU Affero General Public License
+ along with this program. If not, see <http://www.gnu.org/licenses/>.
- You should have received a copy of the GNU General Public License
- along with GNUnet; see the file COPYING. If not, write to the
- Free Software Foundation, Inc., 59 Temple Place - Suite 330,
- Boston, MA 02111-1307, USA.
+ SPDX-License-Identifier: AGPL3.0-or-later
*/
-
/**
- *
* @file gns/gnunet-service-gns_interceptor.c
* @brief GNUnet GNS interceptor logic
* @author Martin Schanzenbach
+ * @author Christian Grothoff
*/
#include "platform.h"
#include "gnunet_util_lib.h"
-#include "gnunet_transport_service.h"
#include "gnunet_dns_service.h"
#include "gnunet_dnsparser_lib.h"
+#include "gnunet-service-gns.h"
#include "gnunet-service-gns_resolver.h"
+#include "gnunet-service-gns_interceptor.h"
#include "gns.h"
-#define MAX_DNS_LABEL_LENGTH 63
/**
* Handle to a DNS intercepted
*/
struct InterceptLookupHandle
{
- /* the request handle to reply to */
+
+ /**
+ * We keep these in a DLL.
+ */
+ struct InterceptLookupHandle *next;
+
+ /**
+ * We keep these in a DLL.
+ */
+ struct InterceptLookupHandle *prev;
+
+ /**
+ * the request handle to reply to
+ */
struct GNUNET_DNS_RequestHandle *request_handle;
-
- /* the dns parser packet received */
+
+ /**
+ * the dns parser packet received
+ */
struct GNUNET_DNSPARSER_Packet *packet;
-
- /* the query parsed from the packet */
- struct GNUNET_DNSPARSER_Query *query;
+
+ /**
+ * Handle for the lookup operation.
+ */
+ struct GNS_ResolverHandle *lookup;
+
};
static struct GNUNET_DNS_Handle *dns_handle;
/**
- * The root zone for this interceptor
+ * Head of the DLL.
*/
-static struct GNUNET_CRYPTO_ShortHashCode our_zone;
+static struct InterceptLookupHandle *ilh_head;
/**
- * Our priv key
+ * Tail of the DLL.
*/
-static struct GNUNET_CRYPTO_RsaPrivateKey *our_key;
+static struct InterceptLookupHandle *ilh_tail;
-/**
- * Default timeout
- */
-static struct GNUNET_TIME_Relative default_lookup_timeout;
/**
* Reply to dns request with the result from our lookup.
* @param rd the record data
*/
static void
-reply_to_dns(void* cls, uint32_t rd_count,
- const struct GNUNET_NAMESTORE_RecordData *rd)
+reply_to_dns (void *cls, uint32_t rd_count,
+ const struct GNUNET_GNSRECORD_Data *rd)
{
- int i;
+ struct InterceptLookupHandle *ilh = cls;
+ struct GNUNET_DNSPARSER_Packet *packet = ilh->packet;
+ struct GNUNET_DNSPARSER_Query *query = &packet->queries[0];
+ uint32_t i;
size_t len;
int ret;
char *buf;
- struct InterceptLookupHandle* ilh = (struct InterceptLookupHandle*)cls;
- struct GNUNET_DNSPARSER_Packet *packet = ilh->packet;
- unsigned int num_answers = 0;
-
-
- /**
- * Put records in the DNS packet and modify it
- * to a response
- */
+ unsigned int num_answers;
+ unsigned int skip_answers;
+ unsigned int skip_additional;
+ size_t off = 0;
+
+ /* Put records in the DNS packet */
+ num_answers = 0;
for (i=0; i < rd_count; i++)
- {
- if (rd[i].record_type == ilh->query->type)
+ if (rd[i].record_type == query->type)
num_answers++;
- }
-
- struct GNUNET_DNSPARSER_Record answer_records[num_answers];
- struct GNUNET_DNSPARSER_Record additional_records[rd_count-(num_answers)];
- packet->answers = answer_records;
- packet->additional_records = additional_records;
+ skip_answers = 0;
+ skip_additional = 0;
- for (i=0; i < rd_count; i++)
{
- GNUNET_log(GNUNET_ERROR_TYPE_DEBUG,
- "Adding type %d to DNS response\n", rd[i].record_type);
- GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "Name: %s\n", ilh->query->name);
- GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "Record %d/%d\n", i+1, rd_count);
- GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "Record len %d\n", rd[i].data_size);
-
- if (rd[i].record_type == ilh->query->type)
+ struct GNUNET_DNSPARSER_Record answer_records[num_answers];
+ struct GNUNET_DNSPARSER_Record additional_records[rd_count - num_answers];
+
+ packet->answers = answer_records;
+ packet->additional_records = additional_records;
+ /* FIXME: need to handle #GNUNET_GNSRECORD_RF_SHADOW_RECORD option
+ (by ignoring records where this flag is set if there is any
+ other record of that type in the result set) */
+ for (i=0; i < rd_count; i++)
{
- answer_records[i].name = ilh->query->name;
- answer_records[i].type = rd[i].record_type;
- switch(rd[i].record_type)
+ if (rd[i].record_type == query->type)
{
- case GNUNET_GNS_RECORD_TYPE_NS:
- case GNUNET_GNS_RECORD_TYPE_CNAME:
- case GNUNET_GNS_RECORD_TYPE_PTR:
- answer_records[i].data.hostname = (char*)rd[i].data;
- break;
- case GNUNET_GNS_RECORD_TYPE_SOA:
- answer_records[i].data.soa =
- (struct GNUNET_DNSPARSER_SoaRecord *)rd[i].data;
- break;
- case GNUNET_GNS_RECORD_MX:
- answer_records[i].data.mx =
- (struct GNUNET_DNSPARSER_MxRecord *)rd[i].data;
- break;
- default:
- answer_records[i].data.raw.data_len = rd[i].data_size;
- answer_records[i].data.raw.data = (char*)rd[i].data;
+ answer_records[i - skip_answers].name = query->name;
+ answer_records[i - skip_answers].type = rd[i].record_type;
+ switch(rd[i].record_type)
+ {
+ case GNUNET_DNSPARSER_TYPE_NS:
+ case GNUNET_DNSPARSER_TYPE_CNAME:
+ case GNUNET_DNSPARSER_TYPE_PTR:
+ answer_records[i - skip_answers].data.hostname
+ = GNUNET_DNSPARSER_parse_name (rd[i].data,
+ rd[i].data_size,
+ &off);
+ if ( (off != rd[i].data_size) ||
+ (NULL == answer_records[i].data.hostname) )
+ {
+ GNUNET_break_op (0);
+ skip_answers++;
+ }
+ break;
+ case GNUNET_DNSPARSER_TYPE_SOA:
+ answer_records[i - skip_answers].data.soa
+ = GNUNET_DNSPARSER_parse_soa (rd[i].data,
+ rd[i].data_size,
+ &off);
+ if ( (off != rd[i].data_size) ||
+ (NULL == answer_records[i].data.soa) )
+ {
+ GNUNET_break_op (0);
+ skip_answers++;
+ }
+ break;
+ case GNUNET_DNSPARSER_TYPE_SRV:
+ /* FIXME: SRV is not yet supported */
+ skip_answers++;
+ break;
+ case GNUNET_DNSPARSER_TYPE_MX:
+ answer_records[i - skip_answers].data.mx
+ = GNUNET_DNSPARSER_parse_mx (rd[i].data,
+ rd[i].data_size,
+ &off);
+ if ( (off != rd[i].data_size) ||
+ (NULL == answer_records[i].data.hostname) )
+ {
+ GNUNET_break_op (0);
+ skip_answers++;
+ }
+ break;
+ default:
+ answer_records[i - skip_answers].data.raw.data_len = rd[i].data_size;
+ answer_records[i - skip_answers].data.raw.data = (char*)rd[i].data;
+ break;
+ }
+ GNUNET_break (0 == (rd[i - skip_answers].flags & GNUNET_GNSRECORD_RF_RELATIVE_EXPIRATION));
+ answer_records[i - skip_answers].expiration_time.abs_value_us = rd[i].expiration_time;
+ answer_records[i - skip_answers].dns_traffic_class = GNUNET_TUN_DNS_CLASS_INTERNET;
+ }
+ else
+ {
+ additional_records[i - skip_additional].name = query->name;
+ additional_records[i - skip_additional].type = rd[i].record_type;
+ switch(rd[i].record_type)
+ {
+ case GNUNET_DNSPARSER_TYPE_NS:
+ case GNUNET_DNSPARSER_TYPE_CNAME:
+ case GNUNET_DNSPARSER_TYPE_PTR:
+ additional_records[i - skip_additional].data.hostname
+ = GNUNET_DNSPARSER_parse_name (rd[i].data,
+ rd[i].data_size,
+ &off);
+ if ( (off != rd[i].data_size) ||
+ (NULL == additional_records[i].data.hostname) )
+ {
+ GNUNET_break_op (0);
+ skip_additional++;
+ }
+ break;
+ case GNUNET_DNSPARSER_TYPE_SOA:
+ additional_records[i - skip_additional].data.soa
+ = GNUNET_DNSPARSER_parse_soa (rd[i].data,
+ rd[i].data_size,
+ &off);
+ if ( (off != rd[i].data_size) ||
+ (NULL == additional_records[i].data.hostname) )
+ {
+ GNUNET_break_op (0);
+ skip_additional++;
+ }
+ break;
+ case GNUNET_DNSPARSER_TYPE_MX:
+ additional_records[i - skip_additional].data.mx
+ = GNUNET_DNSPARSER_parse_mx (rd[i].data,
+ rd[i].data_size,
+ &off);
+ if ( (off != rd[i].data_size) ||
+ (NULL == additional_records[i].data.hostname) )
+ {
+ GNUNET_break_op (0);
+ skip_additional++;
+ }
+ break;
+ case GNUNET_DNSPARSER_TYPE_SRV:
+ /* FIXME: SRV is not yet supported */
+ skip_answers++;
+ break;
+ default:
+ additional_records[i - skip_additional].data.raw.data_len = rd[i].data_size;
+ additional_records[i - skip_additional].data.raw.data = (char*)rd[i].data;
+ break;
+ }
+ GNUNET_break (0 == (rd[i - skip_additional].flags & GNUNET_GNSRECORD_RF_RELATIVE_EXPIRATION));
+ additional_records[i - skip_additional].expiration_time.abs_value_us = rd[i].expiration_time;
+ additional_records[i - skip_additional].dns_traffic_class = GNUNET_TUN_DNS_CLASS_INTERNET;
}
- answer_records[i].expiration_time = rd[i].expiration;
- answer_records[i].class = GNUNET_DNSPARSER_CLASS_INTERNET;//hmmn
}
+ packet->num_answers = num_answers - skip_answers;
+ packet->num_additional_records = rd_count - num_answers - skip_additional;
+ packet->flags.authoritative_answer = 1;
+ if (NULL == rd)
+ packet->flags.return_code = GNUNET_TUN_DNS_RETURN_CODE_NAME_ERROR;
else
+ packet->flags.return_code = GNUNET_TUN_DNS_RETURN_CODE_NO_ERROR;
+ packet->flags.query_or_response = 1;
+ ret = GNUNET_DNSPARSER_pack (packet,
+ 1024, /* maximum allowed size for DNS reply */
+ &buf,
+ &len);
+ if (GNUNET_OK != ret)
{
- additional_records[i].name = ilh->query->name;
- additional_records[i].type = rd[i].record_type;
- switch(rd[i].record_type)
- {
- case GNUNET_GNS_RECORD_TYPE_NS:
- case GNUNET_GNS_RECORD_TYPE_CNAME:
- case GNUNET_GNS_RECORD_TYPE_PTR:
- additional_records[i].data.hostname = (char*)rd[i].data;
- break;
- case GNUNET_GNS_RECORD_TYPE_SOA:
- additional_records[i].data.soa =
- (struct GNUNET_DNSPARSER_SoaRecord *)rd[i].data;
- break;
- case GNUNET_GNS_RECORD_MX:
- additional_records[i].data.mx =
- (struct GNUNET_DNSPARSER_MxRecord *)rd[i].data;
- break;
- default:
- additional_records[i].data.raw.data_len = rd[i].data_size;
- additional_records[i].data.raw.data = (char*)rd[i].data;
- }
- additional_records[i].expiration_time = rd[i].expiration;
- additional_records[i].class = GNUNET_DNSPARSER_CLASS_INTERNET;//hmmn
+ GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
+ _("Error converting GNS response to DNS response!\n"));
+ if (GNUNET_NO == ret)
+ GNUNET_free (buf);
}
+ else
+ {
+ GNUNET_DNS_request_answer (ilh->request_handle,
+ len,
+ buf);
+ GNUNET_free (buf);
+ }
+ packet->num_answers = 0;
+ packet->answers = NULL;
+ packet->num_additional_records = 0;
+ packet->additional_records = NULL;
+ GNUNET_DNSPARSER_free_packet (packet);
}
-
- packet->num_answers = num_answers;
- packet->num_additional_records = rd_count-(num_answers);
-
- packet->flags.authoritative_answer = 1;
-
- if (rd == NULL)
- packet->flags.return_code = GNUNET_DNSPARSER_RETURN_CODE_NAME_ERROR;
- else
- packet->flags.return_code = GNUNET_DNSPARSER_RETURN_CODE_NO_ERROR;
-
- packet->flags.query_or_response = 1;
-
-
- /**
- * Reply to DNS
- */
- GNUNET_log(GNUNET_ERROR_TYPE_DEBUG,
- "Building DNS response\n");
- ret = GNUNET_DNSPARSER_pack (packet,
- 1024, /* FIXME magic from dns redirector */
- &buf,
- &len);
- GNUNET_log(GNUNET_ERROR_TYPE_DEBUG,
- "Built DNS response! (ret=%d,len=%d)\n", ret, len);
- if (ret == GNUNET_OK)
- {
- GNUNET_log(GNUNET_ERROR_TYPE_DEBUG,
- "Answering DNS request\n");
- GNUNET_DNS_request_answer(ilh->request_handle,
- len,
- buf);
-
- GNUNET_free(buf);
- GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "Answered DNS request\n");
- }
- else
- {
- GNUNET_log(GNUNET_ERROR_TYPE_ERROR,
- "Error building DNS response! (ret=%d)", ret);
- }
-
- packet->num_answers = 0;
- packet->answers = NULL;
- packet->num_additional_records = 0;
- packet->additional_records = NULL;
- GNUNET_DNSPARSER_free_packet(packet);
- GNUNET_free(ilh);
-}
-
-
-/**
- * Entry point for name resolution
- * Setup a new query and try to resolve
- *
- * @param request the request handle of the DNS request from a client
- * @param p the DNS query packet we received
- * @param q the DNS query we received parsed from p
- */
-static void
-start_resolution_for_dns(struct GNUNET_DNS_RequestHandle *request,
- struct GNUNET_DNSPARSER_Packet *p,
- struct GNUNET_DNSPARSER_Query *q)
-{
- struct InterceptLookupHandle* ilh;
-
- GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
- "Starting resolution for %s (type=%d)!\n",
- q->name, q->type);
-
- ilh = GNUNET_malloc(sizeof(struct InterceptLookupHandle));
- ilh->packet = p;
- ilh->query = q;
- ilh->request_handle = request;
-
- /* Start resolution in our zone */
- gns_resolver_lookup_record(our_zone, our_zone, q->type, q->name,
- our_key,
- default_lookup_timeout,
- &reply_to_dns, ilh);
+ GNUNET_CONTAINER_DLL_remove (ilh_head, ilh_tail, ilh);
+ GNUNET_free (ilh);
}
-
/**
- * The DNS request handler
- * Called for every incoming DNS request.
+ * The DNS request handler. Called for every incoming DNS request.
*
- * @param cls closure
+ * @param cls closure, unused
* @param rh request handle to user for reply
- * @param request_length number of bytes in request
- * @param request udp payload of the DNS request
+ * @param request_length number of bytes in @a request
+ * @param request UDP payload of the DNS request
*/
static void
-handle_dns_request(void *cls,
- struct GNUNET_DNS_RequestHandle *rh,
- size_t request_length,
- const char *request)
+handle_dns_request (void *cls,
+ struct GNUNET_DNS_RequestHandle *rh,
+ size_t request_length,
+ const char *request)
{
struct GNUNET_DNSPARSER_Packet *p;
+ struct InterceptLookupHandle *ilh;
+ struct GNUNET_CRYPTO_EcdsaPublicKey zone;
- GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Hijacked a DNS request...processing\n");
- p = GNUNET_DNSPARSER_parse (request, request_length);
-
- if (NULL == p)
+ GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+ "Hijacked a DNS request. Processing.\n");
+ if (NULL == (p = GNUNET_DNSPARSER_parse (request, request_length)))
{
GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
- "Received malformed DNS packet, leaving it untouched\n");
+ "Received malformed DNS packet, leaving it untouched.\n");
GNUNET_DNS_request_forward (rh);
GNUNET_DNSPARSER_free_packet (p);
return;
}
-
- /**
- * Check tld and decide if we or
- * legacy dns is responsible
- *
- * FIXME now in theory there could be more than 1 query in the request
- * but if this is case we get into trouble:
- * either we query the GNS or the DNS. We cannot do both!
- * So I suggest to either only allow a single query per request or
- * only allow GNS or DNS requests.
- * The way it is implemented here now is buggy and will lead to erratic
- * behaviour (if multiple queries are present).
- */
- if (p->num_queries == 0)
+
+ /* Check TLD and decide if we or legacy dns is responsible */
+ if (1 != p->num_queries)
{
GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
- "No Queries in DNS packet... forwarding\n");
+ "Not exactly one query in DNS packet. Forwarding untouched.\n");
GNUNET_DNS_request_forward (rh);
GNUNET_DNSPARSER_free_packet(p);
return;
}
- if (p->num_queries > 1)
- {
- /* Note: We could also look for .gnunet */
- GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
- ">1 queriy in DNS packet... odd. We only process #1\n");
- }
-
-
- /**
- * Check for .gnunet/.zkey
- */
-
- if ((is_gnunet_tld(p->queries[0].name) == GNUNET_YES) ||
- (is_zkey_tld(p->queries[0].name) == GNUNET_YES) ||
- (strcmp(p->queries[0].name, GNUNET_GNS_TLD) == 0))
+ /* Check for GNS TLDs. */
+ if (GNUNET_YES ==
+ GNS_find_tld (GNS_get_tld (p->queries[0].name),
+ &zone))
{
- start_resolution_for_dns(rh, p, p->queries);
- }
- else
- {
- /**
- * This request does not concern us. Forward to real DNS.
- */
- GNUNET_log(GNUNET_ERROR_TYPE_DEBUG,
- "Request for %s is forwarded to DNS\n", p->queries[0].name);
- GNUNET_DNS_request_forward (rh);
- GNUNET_DNSPARSER_free_packet (p);
+ /* Start resolution in GNS */
+ ilh = GNUNET_new (struct InterceptLookupHandle);
+ GNUNET_CONTAINER_DLL_insert (ilh_head,
+ ilh_tail,
+ ilh);
+ ilh->packet = p;
+ ilh->request_handle = rh;
+ ilh->lookup = GNS_resolver_lookup (&zone,
+ p->queries[0].type,
+ p->queries[0].name,
+ GNUNET_NO,
+ &reply_to_dns, ilh);
+ return;
}
-
+ /* This request does not concern us. Forward to real DNS. */
+ GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+ "Request for `%s' is forwarded to DNS untouched.\n",
+ p->queries[0].name);
+ GNUNET_DNS_request_forward (rh);
+ GNUNET_DNSPARSER_free_packet (p);
}
/**
* Initialized the interceptor
*
- * @param zone the zone to work in
- * @param key the prov key of the zone (can be null, needed for caching)
* @param c the configuration
- * @return GNUNET_OK on success
+ * @return #GNUNET_OK on success
*/
int
-gns_interceptor_init(struct GNUNET_CRYPTO_ShortHashCode zone,
- struct GNUNET_CRYPTO_RsaPrivateKey *key,
- const struct GNUNET_CONFIGURATION_Handle *c)
+GNS_interceptor_init (const struct GNUNET_CONFIGURATION_Handle *c)
{
- unsigned long long default_lookup_timeout_secs = 0;
-
- GNUNET_log(GNUNET_ERROR_TYPE_INFO,
- "DNS hijacking enabled... connecting to service.\n");
-
- our_zone = zone;
- our_key = key;
- /**
- * Do gnunet dns init here
- */
- dns_handle = GNUNET_DNS_connect(c,
- GNUNET_DNS_FLAG_PRE_RESOLUTION,
- &handle_dns_request, /* rh */
- NULL); /* Closure */
-
- if (GNUNET_OK ==
- GNUNET_CONFIGURATION_get_value_number(c, "gns",
- "DEFAULT_LOOKUP_TIMEOUT",
- &default_lookup_timeout_secs))
- {
- default_lookup_timeout = GNUNET_TIME_relative_multiply(
- GNUNET_TIME_UNIT_SECONDS,
- default_lookup_timeout_secs);
- }
-
+ GNUNET_log (GNUNET_ERROR_TYPE_INFO,
+ "DNS hijacking enabled. Connecting to DNS service.\n");
+ dns_handle = GNUNET_DNS_connect (c,
+ GNUNET_DNS_FLAG_PRE_RESOLUTION,
+ &handle_dns_request,
+ NULL);
if (NULL == dns_handle)
{
- GNUNET_log(GNUNET_ERROR_TYPE_ERROR,
- "Failed to connect to the dnsservice!\n");
+ GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+ _("Failed to connect to the DNS service!\n"));
return GNUNET_SYSERR;
}
-
return GNUNET_YES;
}
+
/**
* Disconnect from interceptor
*/
void
-gns_interceptor_stop(void)
+GNS_interceptor_done ()
{
- if (dns_handle)
- GNUNET_DNS_disconnect(dns_handle);
+ struct InterceptLookupHandle *ilh;
+
+ while (NULL != (ilh = ilh_head))
+ {
+ GNUNET_CONTAINER_DLL_remove (ilh_head,
+ ilh_tail,
+ ilh);
+ GNS_resolver_lookup_cancel (ilh->lookup);
+ GNUNET_DNS_request_drop (ilh->request_handle);
+ GNUNET_DNSPARSER_free_packet (ilh->packet);
+ GNUNET_free (ilh);
+ }
+ if (NULL != dns_handle)
+ {
+ GNUNET_DNS_disconnect (dns_handle);
+ dns_handle = NULL;
+ }
}
-/* end of gns_interceptor.c */
+/* end of gnunet-service-gns_interceptor.c */
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