Imported Upstream version 0.9.3upstream/0.9.3

1 files changed, 394 insertions, 0 deletions

diff --git a/src/gns/gnunet-service-gns_interceptor.c b/src/gns/gnunet-service-gns_interceptor.c
new file mode 100644
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--- /dev/null
+++ b/src/gns/gnunet-service-gns_interceptor.c
@@ -0,0 +1,394 @@
+/*
+     This file is part of GNUnet.
+     (C) 2009, 2010, 2011 Christian Grothoff (and other contributing authors)
+
+     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 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.
+
+     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.
+*/
+
+/**
+ *
+ * @file gns/gnunet-service-gns_interceptor.c
+ * @brief GNUnet GNS interceptor logic
+ * @author Martin Schanzenbach
+ */
+#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_resolver.h"
+#include "gns.h"
+
+#define MAX_DNS_LABEL_LENGTH 63
+
+/**
+ * Handle to a DNS intercepted
+ * reslution request
+ */
+struct InterceptLookupHandle
+{
+  /* the request handle to reply to */
+  struct GNUNET_DNS_RequestHandle *request_handle;
+  
+  /* the dns parser packet received */
+  struct GNUNET_DNSPARSER_Packet *packet;
+  
+  /* the query parsed from the packet */
+  struct GNUNET_DNSPARSER_Query *query;
+};
+
+
+/**
+ * Our handle to the DNS handler library
+ */
+static struct GNUNET_DNS_Handle *dns_handle;
+
+/**
+ * The root zone for this interceptor
+ */
+static struct GNUNET_CRYPTO_ShortHashCode our_zone;
+
+/**
+ * Our priv key
+ */
+static struct GNUNET_CRYPTO_RsaPrivateKey *our_key;
+
+/**
+ * Default timeout
+ */
+static struct GNUNET_TIME_Relative default_lookup_timeout;
+
+/**
+ * Reply to dns request with the result from our lookup.
+ *
+ * @param cls the closure to the request (an InterceptLookupHandle)
+ * @param rd_count the number of records to return
+ * @param rd the record data
+ */
+static void
+reply_to_dns(void* cls, uint32_t rd_count,
+             const struct GNUNET_NAMESTORE_RecordData *rd)
+{
+  int 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
+   */
+  for (i=0; i < rd_count; i++)
+  {
+    if (rd[i].record_type == ilh->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;
+
+  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)
+    {
+      answer_records[i].name = ilh->query->name;
+      answer_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:
+         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].expiration_time = rd[i].expiration;
+      answer_records[i].class = GNUNET_DNSPARSER_CLASS_INTERNET;//hmmn
+    }
+    else
+    {
+      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
+    }
+  }
+  
+  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);
+}
+
+
+
+/**
+ * The DNS request handler
+ * Called for every incoming DNS request.
+ *
+ * @param cls closure
+ * @param rh request handle to user for reply
+ * @param request_length number of bytes in 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)
+{
+  struct GNUNET_DNSPARSER_Packet *p;
+
+  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_WARNING,
+                "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)
+  {
+    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+                "No Queries in DNS packet... forwarding\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))
+  {
+    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);
+  }
+
+}
+
+
+/**
+ * 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
+ */
+int
+gns_interceptor_init(struct GNUNET_CRYPTO_ShortHashCode zone,
+                     struct GNUNET_CRYPTO_RsaPrivateKey *key,
+                     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);
+  }
+
+  if (NULL == dns_handle)
+  {
+    GNUNET_log(GNUNET_ERROR_TYPE_ERROR,
+             "Failed to connect to the dnsservice!\n");
+    return GNUNET_SYSERR;
+  }
+
+  return GNUNET_YES;
+}
+
+/**
+ * Disconnect from interceptor
+ */
+void
+gns_interceptor_stop(void)
+{
+  if (dns_handle)
+    GNUNET_DNS_disconnect(dns_handle);
+}
+
+/* end of gns_interceptor.c */