Use the DNSPARSER and DNSSTUB libraries in the resolver service

We are not using the libc functions anymore for forward and backup
DNS resolutions and the DNSPARSER and DNSSTUB libraries instead.
This has the advantage that the APIs are asynchronous now and
thus multiple DNS resolutions can be done in parallel.

This breaks support for Windows and other operating systems that
don't use /etc/resolv.conf for defining DNS servers. For fixing
this the function lookup_dns_servers can be extended with different
lookup mechanisms.

1 files changed, 18 insertions, 8 deletions

diff --git a/src/util/resolver_api.c b/src/util/resolver_api.c
index b94819f06..8a054327b 100644
--- a/src/util/resolver_api.c
+++ b/src/util/resolver_api.c
@@ -68,10 +68,10 @@ static struct GNUNET_RESOLVER_RequestHandle *req_head;
  */
 static struct GNUNET_RESOLVER_RequestHandle *req_tail;
 
-/**
- * ID of the last request we sent to the service
- */
-static uint32_t last_request_id;
+///**
+// * ID of the last request we sent to the service
+// */
+//static uint16_t last_request_id;
 
 /**
  * How long should we wait to reconnect?
@@ -445,7 +445,7 @@ process_requests ()
                              GNUNET_MESSAGE_TYPE_RESOLVER_REQUEST);
   msg->direction = htonl (rh->direction);
   msg->af = htonl (rh->af);
-  msg->id = htonl (rh->id);
+  msg->id = htons (rh->id);
   GNUNET_memcpy (&msg[1],
                  &rh[1],
                  rh->data_len);
@@ -491,7 +491,7 @@ handle_response (void *cls,
   struct GNUNET_RESOLVER_RequestHandle *rh = req_head;
   uint16_t size;
   char *nret;
-  uint32_t request_id = msg->id;
+  uint16_t request_id = msg->id;
 
   for (; rh != NULL; rh = rh->next)
   {
@@ -911,6 +911,14 @@ handle_lookup_timeout (void *cls)
 }
 
 
+static uint16_t
+get_request_id ()
+{
+  return (uint16_t) GNUNET_CRYPTO_random_u32 (GNUNET_CRYPTO_QUALITY_NONCE,
+                                              UINT16_MAX);
+}
+
+
 /**
  * Convert a string to one or more IP addresses.
  *
@@ -945,7 +953,8 @@ GNUNET_RESOLVER_ip_get (const char *hostname,
        hostname);
   rh = GNUNET_malloc (sizeof (struct GNUNET_RESOLVER_RequestHandle) + slen);
   rh->af = af;
-  rh->id = ++last_request_id;
+  //rh->id = ++last_request_id;
+  rh->id = get_request_id ();
   rh->addr_callback = callback;
   rh->cls = callback_cls;
   GNUNET_memcpy (&rh[1],
@@ -1092,7 +1101,8 @@ GNUNET_RESOLVER_hostname_get (const struct sockaddr *sa,
   rh->name_callback = callback;
   rh->cls = cls;
   rh->af = sa->sa_family;
-  rh->id = ++last_request_id;
+  //rh->id = ++last_request_id;
+  rh->id = get_request_id ();
   rh->timeout = GNUNET_TIME_relative_to_absolute (timeout);
   GNUNET_memcpy (&rh[1],
                  ip,