X-Git-Url: https://git.librecmc.org/?a=blobdiff_plain;f=src%2Futil%2Fresolver_api.c;h=46ac52586c752c1bb8baff3f9728d04779a52578;hb=267f7c5a9a354b8959607c7bc031906c02b61be4;hp=96396bfcccc7a61ade1c5c0cd65bc91cdecbe66f;hpb=dca2e627584720657437f519f7d12a5334acc2cc;p=oweals%2Fgnunet.git

diff --git a/src/util/resolver_api.c b/src/util/resolver_api.c
index 96396bfcc..46ac52586 100644
--- a/src/util/resolver_api.c
+++ b/src/util/resolver_api.c
@@ -1,10 +1,10 @@
 /*
      This file is part of GNUnet.
-     (C) 2009 Christian Grothoff (and other contributing authors)
+     (C) 2009-2013 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 2, or (at your
+     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
@@ -24,14 +24,14 @@
  * @author Christian Grothoff
  */
 #include "platform.h"
-#include "gnunet_getopt_lib.h"
-#include "gnunet_os_lib.h"
-#include "gnunet_client_lib.h"
+#include "gnunet_util_lib.h"
 #include "gnunet_protocols.h"
 #include "gnunet_resolver_service.h"
-#include "gnunet_server_lib.h"
 #include "resolver.h"
 
+#define LOG(kind,...) GNUNET_log_from (kind, "resolver-api", __VA_ARGS__)
+
+#define LOG_STRERROR(kind,syscall) GNUNET_log_from_strerror (kind, "resolver-api", syscall)
 
 /**
  * Maximum supported length for a hostname
@@ -49,6 +49,44 @@ static const char *loopback[] = {
 };
 
 
+/**
+ * Configuration.
+ */
+static const struct GNUNET_CONFIGURATION_Handle *resolver_cfg;
+
+/**
+ * Our connection to the resolver service, created on-demand, but then
+ * persists until error or shutdown.
+ */
+static struct GNUNET_CLIENT_Connection *client;
+
+/**
+ * Head of DLL of requests.
+ */
+static struct GNUNET_RESOLVER_RequestHandle *req_head;
+
+/**
+ * Tail of DLL of requests.
+ */
+static struct GNUNET_RESOLVER_RequestHandle *req_tail;
+
+/**
+ * How long should we wait to reconnect?
+ */
+static struct GNUNET_TIME_Relative backoff;
+
+/**
+ * Task for reconnecting.
+ */
+static GNUNET_SCHEDULER_TaskIdentifier r_task;
+
+/**
+ * Task ID of shutdown task; only present while we have a
+ * connection to the resolver service.
+ */
+static GNUNET_SCHEDULER_TaskIdentifier s_task;
+
+
 /**
  * Handle to a request given to the resolver.  Can be used to cancel
  * the request prior to the timeout or successful execution.  Also
@@ -57,6 +95,16 @@ static const char *loopback[] = {
 struct GNUNET_RESOLVER_RequestHandle
 {
 
+  /**
+   * Next entry in DLL of requests.
+   */
+  struct GNUNET_RESOLVER_RequestHandle *next;
+
+  /**
+   * Previous entry in DLL of requests.
+   */
+  struct GNUNET_RESOLVER_RequestHandle *prev;
+
   /**
    * Callback if this is an name resolution request,
    * otherwise NULL.
@@ -75,40 +123,47 @@ struct GNUNET_RESOLVER_RequestHandle
   void *cls;
 
   /**
-   * Our connection to the resolver service.
+   * When should this request time out?
+   */
+  struct GNUNET_TIME_Absolute timeout;
+
+  /**
+   * Task handle for numeric lookups.
    */
-  struct GNUNET_CLIENT_Connection *client;
+  GNUNET_SCHEDULER_TaskIdentifier task;
 
   /**
-   * Our scheduler.
+   * Desired address family.
    */
-  struct GNUNET_SCHEDULER_Handle *sched;
+  int af;
 
   /**
-   * Name of the host that we are resolving.
+   * Has this request been transmitted to the service?
+   * GNUNET_YES if transmitted
+   * GNUNET_YES if not transmitted
+   * GNUNET_SYSERR when request was canceled
    */
-  const char *hostname;
+  int was_transmitted;
 
   /**
-   * When should this request time out?
+   * Did we add this request to the queue?
    */
-  struct GNUNET_TIME_Absolute timeout;
+  int was_queued;
 
   /**
-   * Task handle for numeric lookups.
+   * Desired direction (IP to name or name to IP)
    */
-  GNUNET_SCHEDULER_TaskIdentifier task;
+  int direction;
 
   /**
-   * Desired address family.
+   * GNUNET_YES if a response was received
    */
-  int domain;
+  int received_response;
 
   /**
-   * Length of the "struct sockaddr" that follows this
-   * struct (only for reverse lookup).
+   * Length of the data that follows this struct.
    */
-  socklen_t salen;
+  size_t data_len;
 };
 
 
@@ -117,7 +172,7 @@ struct GNUNET_RESOLVER_RequestHandle
  * (or equivalent).
  */
 static void
-check_config (const struct GNUNET_CONFIGURATION_Handle *cfg)
+check_config ()
 {
   char *hostname;
   unsigned int i;
@@ -136,157 +191,292 @@ check_config (const struct GNUNET_CONFIGURATION_Handle *cfg)
   v6.sin6_len = sizeof (v6);
 #endif
   if (GNUNET_OK !=
-      GNUNET_CONFIGURATION_get_value_string (cfg,
-                                             "resolver",
+      GNUNET_CONFIGURATION_get_value_string (resolver_cfg, "resolver",
                                              "HOSTNAME", &hostname))
-    {
-      GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
-                  _("Must specify `%s' for `%s' in configuration!\n"),
-                  "HOSTNAME", "resolver");
-      GNUNET_assert (0);
-    }
-  if ((1 != inet_pton (AF_INET,
-                       hostname,
-                       &v4)) || (1 != inet_pton (AF_INET6, hostname, &v6)))
+  {
+    LOG (GNUNET_ERROR_TYPE_ERROR,
+         _("Must specify `%s' for `%s' in configuration!\n"), "HOSTNAME",
+         "resolver");
+    GNUNET_assert (0);
+  }
+  if ((1 != inet_pton (AF_INET, hostname, &v4)) ||
+      (1 != inet_pton (AF_INET6, hostname, &v6)))
+  {
+    GNUNET_free (hostname);
+    return;
+  }
+  i = 0;
+  while (NULL != loopback[i])
+    if (0 == strcasecmp (loopback[i++], hostname))
     {
       GNUNET_free (hostname);
       return;
     }
-  i = 0;
-  while (loopback[i] != NULL)
-    if (0 == strcasecmp (loopback[i++], hostname))
-      {
-        GNUNET_free (hostname);
-        return;
-      }
-  GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
-              _
-              ("Must specify `%s' or numeric IP address for `%s' of `%s' in configuration!\n"),
-              "localhost", "HOSTNAME", "resolver");
+  LOG (GNUNET_ERROR_TYPE_ERROR,
+       _("Must specify `%s' or numeric IP address for `%s' of `%s' in configuration!\n"),
+       "localhost", "HOSTNAME", "resolver");
   GNUNET_free (hostname);
   GNUNET_assert (0);
 }
 
 
+/**
+ * Create the connection to the resolver service.
+ *
+ * @param cfg configuration to use
+ */
+void
+GNUNET_RESOLVER_connect (const struct GNUNET_CONFIGURATION_Handle *cfg)
+{
+  GNUNET_assert (NULL != cfg);
+  backoff = GNUNET_TIME_UNIT_MILLISECONDS;
+  resolver_cfg = cfg;
+  check_config ();
+}
+
+
+/**
+ * Destroy the connection to the resolver service.
+ */
+void
+GNUNET_RESOLVER_disconnect ()
+{
+  GNUNET_assert (NULL == req_head);
+  GNUNET_assert (NULL == req_tail);
+  if (NULL != client)
+  {
+    LOG (GNUNET_ERROR_TYPE_DEBUG, "Disconnecting from DNS service\n");
+    GNUNET_CLIENT_disconnect (client);
+    client = NULL;
+  }
+  if (GNUNET_SCHEDULER_NO_TASK != r_task)
+  {
+    GNUNET_SCHEDULER_cancel (r_task);
+    r_task = GNUNET_SCHEDULER_NO_TASK;
+  }
+  if (GNUNET_SCHEDULER_NO_TASK != s_task)
+  {
+    GNUNET_SCHEDULER_cancel (s_task);
+    s_task = GNUNET_SCHEDULER_NO_TASK;
+  }
+}
+
+
 /**
  * Convert IP address to string without DNS resolution.
  *
- * @param sa the address 
- * @param salen number of bytes in sa
+ * @param af address family
+ * @param ip the address
+ * @param ip_len number of bytes in ip
  * @return address as a string, NULL on error
  */
 static char *
-no_resolve (const struct sockaddr *sa, socklen_t salen)
+no_resolve (int af,
+	    const void *ip, socklen_t ip_len)
 {
-  char *ret;
-  char inet4[INET_ADDRSTRLEN];
-  char inet6[INET6_ADDRSTRLEN];
+  char buf[INET6_ADDRSTRLEN];
 
-  if (salen < sizeof (struct sockaddr))
-    return NULL;
-  switch (sa->sa_family)
+  switch (af)
+  {
+  case AF_INET:
+    if (ip_len != sizeof (struct in_addr))
+      return NULL;
+    if (NULL ==
+        inet_ntop (AF_INET, ip, buf, sizeof (buf)))
     {
-    case AF_INET:
-      if (salen != sizeof (struct sockaddr_in))
-        return NULL;
-      inet_ntop (AF_INET,
-                 &((struct sockaddr_in *) sa)->sin_addr,
-                 inet4, INET_ADDRSTRLEN);
-      ret = GNUNET_strdup (inet4);
-      break;
-    case AF_INET6:
-      if (salen != sizeof (struct sockaddr_in6))
-        return NULL;
-      inet_ntop (AF_INET6,
-                 &((struct sockaddr_in6 *) sa)->sin6_addr,
-                 inet6, INET6_ADDRSTRLEN);
-      ret = GNUNET_strdup (inet6);
-      break;
-    default:
-      ret = NULL;
-      break;
+      LOG_STRERROR (GNUNET_ERROR_TYPE_WARNING, "inet_ntop");
+      return NULL;
     }
-  return ret;
+    break;
+  case AF_INET6:
+    if (ip_len != sizeof (struct in6_addr))
+      return NULL;
+    if (NULL ==
+        inet_ntop (AF_INET6, ip, buf, sizeof (buf)))
+    {
+      LOG_STRERROR (GNUNET_ERROR_TYPE_WARNING, "inet_ntop");
+      return NULL;
+    }
+    break;
+  default:
+    GNUNET_break (0);
+    return NULL;
+  }
+  return GNUNET_strdup (buf);
 }
 
 
 /**
- * Process the reply from the resolver (which is presumably
- * the numeric IP address for a name resolution request).
+ * Adjust exponential back-off and reconnect to the service.
+ */
+static void
+reconnect ();
+
+
+/**
+ * Process pending requests to the resolver.
+ */
+static void
+process_requests ();
+
+
+/**
+ * Process response with a hostname for a DNS lookup.
  *
- * @param cls the "GNUNET_RESOLVER_RequestHandle" for which this is a reply
- * @param msg reply from the resolver or NULL on error
+ * @param cls our "struct GNUNET_RESOLVER_RequestHandle" context
+ * @param msg message with the hostname, NULL on error
  */
 static void
-handle_address_response (void *cls, const struct GNUNET_MessageHeader *msg)
+handle_response (void *cls, const struct GNUNET_MessageHeader *msg)
 {
   struct GNUNET_RESOLVER_RequestHandle *rh = cls;
   uint16_t size;
-  const struct sockaddr *sa;
-  socklen_t salen;
-
 
-  if (msg == NULL)
+  LOG (GNUNET_ERROR_TYPE_DEBUG,
+       "Receiving response from DNS service\n");
+  if (NULL == msg)
+  {
+    char buf[INET6_ADDRSTRLEN];
+
+    if (NULL != rh->name_callback)
+      LOG (GNUNET_ERROR_TYPE_INFO,
+           _("Timeout trying to resolve IP address `%s'.\n"),
+           inet_ntop (rh->af, (const void *) &rh[1], buf, sizeof(buf)));
+    else
+      LOG (GNUNET_ERROR_TYPE_INFO,
+           _("Timeout trying to resolve hostname `%s'.\n"),
+           (const char *) &rh[1]);
+    /* check if request was canceled */
+    if (GNUNET_SYSERR != rh->was_transmitted)
     {
-      GNUNET_log (GNUNET_ERROR_TYPE_INFO,
-                  _("Timeout trying to resolve hostname `%s'.\n"),
-		  rh->hostname);
-      rh->addr_callback (rh->cls, NULL, 0);
-      GNUNET_CLIENT_disconnect (rh->client, GNUNET_NO);
-      GNUNET_free (rh);
-      return;
+      if (NULL != rh->name_callback)
+      {
+        /* no reverse lookup was successful, return ip as string */
+        if (rh->received_response == GNUNET_NO)
+        {
+          rh->name_callback (rh->cls, no_resolve (rh->af, &rh[1], rh->data_len));
+          rh->name_callback (rh->cls, NULL);
+        }
+        /* at least one reverse lookup was successful */
+        else
+          rh->name_callback (rh->cls, NULL);
+      }
+      if (NULL != rh->addr_callback)
+        rh->addr_callback (rh->cls, NULL, 0);
     }
+    GNUNET_CONTAINER_DLL_remove (req_head, req_tail, rh);
+    GNUNET_free (rh);
+    GNUNET_CLIENT_disconnect (client);
+    client = NULL;
+    reconnect ();
+    return;
+  }
   if (GNUNET_MESSAGE_TYPE_RESOLVER_RESPONSE != ntohs (msg->type))
+  {
+    GNUNET_break (0);
+    GNUNET_CLIENT_disconnect (client);
+    client = NULL;
+    reconnect ();
+    return;
+  }
+  size = ntohs (msg->size);
+  /* message contains not data, just header */
+  if (size == sizeof (struct GNUNET_MessageHeader))
+  {
+    /* check if request was canceled */
+    if (rh->was_transmitted != GNUNET_SYSERR)
+    {
+      if (NULL != rh->name_callback)
+        rh->name_callback (rh->cls, NULL);
+      if (NULL != rh->addr_callback)
+        rh->addr_callback (rh->cls, NULL, 0);
+    }
+    GNUNET_CONTAINER_DLL_remove (req_head, req_tail, rh);
+    GNUNET_free (rh);
+    process_requests ();
+    return;
+  }
+  /* return reverse lookup results to caller */
+  if (NULL != rh->name_callback)
+  {
+    const char *hostname;
+
+    hostname = (const char *) &msg[1];
+    if (hostname[size - sizeof (struct GNUNET_MessageHeader) - 1] != '\0')
     {
       GNUNET_break (0);
-      rh->addr_callback (rh->cls, NULL, 0);
-      GNUNET_CLIENT_disconnect (rh->client, GNUNET_NO);
+      if (rh->was_transmitted != GNUNET_SYSERR)
+        rh->name_callback (rh->cls, NULL);
+      GNUNET_CONTAINER_DLL_remove (req_head, req_tail, rh);
       GNUNET_free (rh);
+      GNUNET_CLIENT_disconnect (client);
+      client = NULL;
+      reconnect ();
       return;
     }
-
-  size = ntohs (msg->size);
-  if (size == sizeof (struct GNUNET_MessageHeader))
+    LOG (GNUNET_ERROR_TYPE_DEBUG, "Resolver returns `%s' for IP `%s'.\n",
+         hostname, GNUNET_a2s ((const void *) &rh[1], rh->data_len));
+    if (rh->was_transmitted != GNUNET_SYSERR)
+      rh->name_callback (rh->cls, hostname);
+    rh->received_response = GNUNET_YES;
+    GNUNET_CLIENT_receive (client, &handle_response, rh,
+                           GNUNET_TIME_absolute_get_remaining (rh->timeout));
+  }
+  /* return lookup results to caller */
+  if (NULL != rh->addr_callback)
+  {
+    struct sockaddr_in v4;
+    struct sockaddr_in6 v6;
+    const struct sockaddr *sa;
+    socklen_t salen;
+    const void *ip;
+    size_t ip_len;
+
+    ip = &msg[1];
+    ip_len = size - sizeof (struct GNUNET_MessageHeader);
+    if (ip_len == sizeof (struct in_addr))
     {
-#if DEBUG_RESOLVER
-      GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
-                  _("Received end message resolving hostname `%s'.\n"),
-		  rh->hostname);
+      memset (&v4, 0, sizeof (v4));
+      v4.sin_family = AF_INET;
+      v4.sin_addr = *(struct in_addr*) ip;
+#if HAVE_SOCKADDR_IN_SIN_LEN
+      v4.sin_len = sizeof (v4);
 #endif
-      rh->addr_callback (rh->cls, NULL, 0);
-      GNUNET_CLIENT_disconnect (rh->client, GNUNET_NO);
-      GNUNET_free (rh);
-      return;
+      salen = sizeof (v4);
+      sa = (const struct sockaddr *) &v4;
+    }
+    else if (ip_len == sizeof (struct in6_addr))
+    {
+      memset (&v6, 0, sizeof (v6));
+      v6.sin6_family = AF_INET6;
+      v6.sin6_addr = *(struct in6_addr*) ip;
+#if HAVE_SOCKADDR_IN_SIN_LEN
+      v6.sin6_len = sizeof (v6);
+#endif
+      salen = sizeof (v6);
+      sa = (const struct sockaddr *) &v6;
     }
-  sa = (const struct sockaddr *) &msg[1];
-  salen = size - sizeof (struct GNUNET_MessageHeader);
-  if (salen < sizeof (struct sockaddr))
+    else
     {
       GNUNET_break (0);
-      rh->addr_callback (rh->cls, NULL, 0);
-      GNUNET_CLIENT_disconnect (rh->client, GNUNET_NO);
+      if (rh->was_transmitted != GNUNET_SYSERR)
+        rh->addr_callback (rh->cls, NULL, 0);
+      GNUNET_CONTAINER_DLL_remove (req_head, req_tail, rh);
       GNUNET_free (rh);
+      GNUNET_CLIENT_disconnect (client);
+      client = NULL;
+      reconnect ();
       return;
     }
-#if DEBUG_RESOLVER
-  {
-    char *ips = no_resolve (sa, salen);
-    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
-		"Resolver returns `%s' for `%s'.\n", ips,
-		rh->hostname);
-    GNUNET_free (ips);
+    rh->addr_callback (rh->cls, sa, salen);
+    GNUNET_CLIENT_receive (client, &handle_response, rh,
+                           GNUNET_TIME_absolute_get_remaining (rh->timeout));
   }
-#endif
-  rh->addr_callback (rh->cls, sa, salen);
-  GNUNET_CLIENT_receive (rh->client,
-                         &handle_address_response,
-                         rh,
-                         GNUNET_TIME_absolute_get_remaining (rh->timeout));
 }
 
 
 /**
- * We've been asked to lookup the address for a hostname and were 
+ * We've been asked to lookup the address for a hostname and were
  * given a valid numeric string.  Perform the callbacks for the
  * numeric addresses.
  *
@@ -299,6 +489,7 @@ numeric_resolution (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
   struct GNUNET_RESOLVER_RequestHandle *rh = cls;
   struct sockaddr_in v4;
   struct sockaddr_in6 v6;
+  const char *hostname;
 
   memset (&v4, 0, sizeof (v4));
   v4.sin_family = AF_INET;
@@ -310,39 +501,37 @@ numeric_resolution (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
 #if HAVE_SOCKADDR_IN_SIN_LEN
   v6.sin6_len = sizeof (v6);
 #endif
-
-  if (((rh->domain == AF_UNSPEC) || (rh->domain == AF_INET)) &&
-      (1 == inet_pton (AF_INET, rh->hostname, &v4.sin_addr)))
-    {
-      rh->addr_callback (rh->cls, (const struct sockaddr *) &v4, sizeof (v4));
-      if ((rh->domain == AF_UNSPEC) &&
-          (1 == inet_pton (AF_INET6, rh->hostname, &v6.sin6_addr)))
-        {
-          /* this can happen on some systems IF "hostname" is "localhost" */
-          rh->addr_callback (rh->cls,
-                             (const struct sockaddr *) &v6, sizeof (v6));
-        }
-      rh->addr_callback (rh->cls, NULL, 0);
-      GNUNET_free (rh);
-      return;
-    }
-  if (((rh->domain == AF_UNSPEC) || (rh->domain == AF_INET6)) &&
-      (1 == inet_pton (AF_INET6, rh->hostname, &v6.sin6_addr)))
+  hostname = (const char *) &rh[1];
+  if (((rh->af == AF_UNSPEC) || (rh->af == AF_INET)) &&
+      (1 == inet_pton (AF_INET, hostname, &v4.sin_addr)))
+  {
+    rh->addr_callback (rh->cls, (const struct sockaddr *) &v4, sizeof (v4));
+    if ((rh->af == AF_UNSPEC) &&
+        (1 == inet_pton (AF_INET6, hostname, &v6.sin6_addr)))
     {
+      /* this can happen on some systems IF "hostname" is "localhost" */
       rh->addr_callback (rh->cls, (const struct sockaddr *) &v6, sizeof (v6));
-      rh->addr_callback (rh->cls, NULL, 0);
-      GNUNET_free (rh);
-      return;
     }
+    rh->addr_callback (rh->cls, NULL, 0);
+    GNUNET_free (rh);
+    return;
+  }
+  if (((rh->af == AF_UNSPEC) || (rh->af == AF_INET6)) &&
+      (1 == inet_pton (AF_INET6, hostname, &v6.sin6_addr)))
+  {
+    rh->addr_callback (rh->cls, (const struct sockaddr *) &v6, sizeof (v6));
+    rh->addr_callback (rh->cls, NULL, 0);
+    GNUNET_free (rh);
+    return;
+  }
   /* why are we here? this task should not have been scheduled! */
   GNUNET_assert (0);
   GNUNET_free (rh);
 }
 
 
-
 /**
- * We've been asked to lookup the address for a hostname and were 
+ * We've been asked to lookup the address for a hostname and were
  * given a variant of "loopback".  Perform the callbacks for the
  * respective loopback numeric addresses.
  *
@@ -368,194 +557,227 @@ loopback_resolution (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
   v6.sin6_len = sizeof (v6);
 #endif
   v6.sin6_addr = in6addr_loopback;
-  switch (rh->domain)
+  switch (rh->af)
+  {
+  case AF_INET:
+    rh->addr_callback (rh->cls, (const struct sockaddr *) &v4, sizeof (v4));
+    break;
+  case AF_INET6:
+    rh->addr_callback (rh->cls, (const struct sockaddr *) &v6, sizeof (v6));
+    break;
+  case AF_UNSPEC:
+    rh->addr_callback (rh->cls, (const struct sockaddr *) &v6, sizeof (v6));
+    rh->addr_callback (rh->cls, (const struct sockaddr *) &v4, sizeof (v4));
+    break;
+  default:
+    GNUNET_break (0);
+    break;
+  }
+  rh->addr_callback (rh->cls, NULL, 0);
+  GNUNET_free (rh);
+}
+
+
+/**
+ * Task executed on system shutdown.
+ */
+static void
+shutdown_task (void *cls,
+	       const struct GNUNET_SCHEDULER_TaskContext *tc)
+{
+  s_task = GNUNET_SCHEDULER_NO_TASK;
+  GNUNET_RESOLVER_disconnect ();
+  backoff = GNUNET_TIME_UNIT_MILLISECONDS;
+}
+
+
+/**
+ * Process pending requests to the resolver.
+ */
+static void
+process_requests ()
+{
+  struct GNUNET_RESOLVER_GetMessage *msg;
+  char buf[GNUNET_SERVER_MAX_MESSAGE_SIZE - 1] GNUNET_ALIGN;
+  struct GNUNET_RESOLVER_RequestHandle *rh;
+
+  if (NULL == client)
+  {
+    reconnect ();
+    return;
+  }
+  rh = req_head;
+  if (NULL == rh)
+  {
+    /* nothing to do, release socket really soon if there is nothing
+     * else happening... */
+    s_task =
+        GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_MILLISECONDS,
+                                      &shutdown_task, NULL);
+    return;
+  }
+  if (GNUNET_YES == rh->was_transmitted)
+    return;                     /* waiting for reply */
+  msg = (struct GNUNET_RESOLVER_GetMessage *) buf;
+  msg->header.size =
+      htons (sizeof (struct GNUNET_RESOLVER_GetMessage) + rh->data_len);
+  msg->header.type = htons (GNUNET_MESSAGE_TYPE_RESOLVER_REQUEST);
+  msg->direction = htonl (rh->direction);
+  msg->af = htonl (rh->af);
+  memcpy (&msg[1], &rh[1], rh->data_len);
+  LOG (GNUNET_ERROR_TYPE_DEBUG,
+       "Transmitting DNS resolution request to DNS service\n");
+  if (GNUNET_OK !=
+      GNUNET_CLIENT_transmit_and_get_response (client, &msg->header,
+                                               GNUNET_TIME_absolute_get_remaining
+                                               (rh->timeout), GNUNET_YES,
+                                               &handle_response, rh))
+  {
+    GNUNET_CLIENT_disconnect (client);
+    client = NULL;
+    GNUNET_break (0);
+    reconnect ();
+    return;
+  }
+  rh->was_transmitted = GNUNET_YES;
+}
+
+
+/**
+ * Now try to reconnect to the resolver service.
+ *
+ * @param cls NULL
+ * @param tc scheduler context
+ */
+static void
+reconnect_task (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
+{
+  r_task = GNUNET_SCHEDULER_NO_TASK;
+  if (NULL == req_head)
+    return;                     /* no work pending */
+  if (0 != (tc->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN))
+    return;
+  LOG (GNUNET_ERROR_TYPE_DEBUG,
+       "Trying to connect to DNS service\n");
+  client = GNUNET_CLIENT_connect ("resolver", resolver_cfg);
+  if (NULL == client)
+  {
+    LOG (GNUNET_ERROR_TYPE_DEBUG,
+	 "Failed to connect, will try again later\n");
+    reconnect ();
+    return;
+  }
+  process_requests ();
+}
+
+
+/**
+ * Adjust exponential back-off and reconnect to the service.
+ */
+static void
+reconnect ()
+{
+  struct GNUNET_RESOLVER_RequestHandle *rh;
+
+  if (GNUNET_SCHEDULER_NO_TASK != r_task)
+    return;
+  GNUNET_assert (NULL == client);
+  if (NULL != (rh = req_head))
+  {
+    switch (rh->was_transmitted)
     {
-    case AF_INET:
-      rh->addr_callback (rh->cls, (const struct sockaddr *) &v4, sizeof (v4));
+    case GNUNET_NO:
+      /* nothing more to do */
       break;
-    case AF_INET6:
-      rh->addr_callback (rh->cls, (const struct sockaddr *) &v6, sizeof (v6));
+    case GNUNET_YES:
+      /* disconnected, transmit again! */
+      rh->was_transmitted = GNUNET_NO;
       break;
-    case AF_UNSPEC:
-      rh->addr_callback (rh->cls, (const struct sockaddr *) &v6, sizeof (v6));
-      rh->addr_callback (rh->cls, (const struct sockaddr *) &v4, sizeof (v4));
+    case GNUNET_SYSERR:
+      /* request was cancelled, remove entirely */
+      GNUNET_CONTAINER_DLL_remove (req_head, req_tail, rh);
+      GNUNET_free (rh);
       break;
     default:
-      GNUNET_break (0);
+      GNUNET_assert (0);
       break;
     }
-  rh->addr_callback (rh->cls, NULL, 0);
-  GNUNET_free (rh);
+  }
+  LOG (GNUNET_ERROR_TYPE_DEBUG,
+       "Will try to connect to DNS service in %s\n",
+       GNUNET_STRINGS_relative_time_to_string (backoff, GNUNET_YES));
+  GNUNET_assert (NULL != resolver_cfg);
+  r_task = GNUNET_SCHEDULER_add_delayed (backoff, &reconnect_task, NULL);
+  backoff = GNUNET_TIME_STD_BACKOFF (backoff);
 }
 
 
 /**
  * Convert a string to one or more IP addresses.
  *
- * @param sched scheduler to use
- * @param cfg configuration to use
  * @param hostname the hostname to resolve
- * @param domain AF_INET or AF_INET6; use AF_UNSPEC for "any"
+ * @param af AF_INET or AF_INET6; use AF_UNSPEC for "any"
  * @param callback function to call with addresses
  * @param callback_cls closure for callback
  * @param timeout how long to try resolving
  * @return handle that can be used to cancel the request, NULL on error
  */
 struct GNUNET_RESOLVER_RequestHandle *
-GNUNET_RESOLVER_ip_get (struct GNUNET_SCHEDULER_Handle *sched,
-                        const struct GNUNET_CONFIGURATION_Handle *cfg,
-                        const char *hostname,
-                        int domain,
+GNUNET_RESOLVER_ip_get (const char *hostname, int af,
                         struct GNUNET_TIME_Relative timeout,
                         GNUNET_RESOLVER_AddressCallback callback,
                         void *callback_cls)
 {
-  struct GNUNET_CLIENT_Connection *client;
-  struct GNUNET_RESOLVER_GetMessage *msg;
   struct GNUNET_RESOLVER_RequestHandle *rh;
   size_t slen;
   unsigned int i;
   struct in_addr v4;
   struct in6_addr v6;
-  char buf[GNUNET_SERVER_MAX_MESSAGE_SIZE];
 
-  check_config (cfg);
   slen = strlen (hostname) + 1;
-  if (slen + sizeof (struct GNUNET_RESOLVER_GetMessage) >
+  if (slen + sizeof (struct GNUNET_RESOLVER_GetMessage) >=
       GNUNET_SERVER_MAX_MESSAGE_SIZE)
-    {
-      GNUNET_break (0);
-      return NULL;
-    }
+  {
+    GNUNET_break (0);
+    return NULL;
+  }
   rh = GNUNET_malloc (sizeof (struct GNUNET_RESOLVER_RequestHandle) + slen);
-  rh->sched = sched;
-  rh->domain = domain;
+  rh->af = af;
   rh->addr_callback = callback;
   rh->cls = callback_cls;
   memcpy (&rh[1], hostname, slen);
-  rh->hostname = (const char *) &rh[1];
+  rh->data_len = slen;
   rh->timeout = GNUNET_TIME_relative_to_absolute (timeout);
-
+  rh->direction = GNUNET_NO;
   /* first, check if this is a numeric address */
-  if (((1 == inet_pton (AF_INET,
-                        hostname,
-                        &v4)) &&
-       ((domain == AF_INET) || (domain == AF_UNSPEC))) ||
-      ((1 == inet_pton (AF_INET6,
-                        hostname,
-                        &v6)) &&
-       ((domain == AF_INET6) || (domain == AF_UNSPEC))))
-    {
-      rh->task = GNUNET_SCHEDULER_add_now (sched,
-					   &numeric_resolution, rh);
-      return rh;
-    }
+  if (((1 == inet_pton (AF_INET, hostname, &v4)) &&
+       ((af == AF_INET) || (af == AF_UNSPEC))) ||
+      ((1 == inet_pton (AF_INET6, hostname, &v6)) &&
+       ((af == AF_INET6) || (af == AF_UNSPEC))))
+  {
+    rh->task = GNUNET_SCHEDULER_add_now (&numeric_resolution, rh);
+    return rh;
+  }
   /* then, check if this is a loopback address */
   i = 0;
-  while (loopback[i] != NULL)
+  while (NULL != loopback[i])
     if (0 == strcasecmp (loopback[i++], hostname))
-      {
-        rh->task = GNUNET_SCHEDULER_add_now (sched,
-					     &loopback_resolution, rh);
-        return rh;
-      }
-
-  client = GNUNET_CLIENT_connect (sched, "resolver", cfg);
-  if (client == NULL)
-    {
-      GNUNET_free (rh);
-      return NULL;
-    }
-  rh->client = client;
-
-  msg = (struct GNUNET_RESOLVER_GetMessage *) buf;
-  msg->header.size =
-    htons (sizeof (struct GNUNET_RESOLVER_GetMessage) + slen);
-  msg->header.type = htons (GNUNET_MESSAGE_TYPE_RESOLVER_REQUEST);
-  msg->direction = htonl (GNUNET_NO);
-  msg->domain = htonl (domain);
-  memcpy (&msg[1], hostname, slen);
-
-#if DEBUG_RESOLVER
-  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
-              _("Resolver requests DNS resolution of hostname `%s'.\n"),
-              hostname);
-#endif
-  if (GNUNET_OK !=
-      GNUNET_CLIENT_transmit_and_get_response (client,
-                                               &msg->header,
-                                               timeout,
-                                               GNUNET_YES,
-                                               &handle_address_response, rh))
     {
-      GNUNET_free (rh);
-      GNUNET_CLIENT_disconnect (client, GNUNET_NO);
-      return NULL;
+      rh->task = GNUNET_SCHEDULER_add_now (&loopback_resolution, rh);
+      return rh;
     }
+  GNUNET_CONTAINER_DLL_insert_tail (req_head, req_tail, rh);
+  rh->was_queued = GNUNET_YES;
+  if (s_task != GNUNET_SCHEDULER_NO_TASK)
+  {
+    GNUNET_SCHEDULER_cancel (s_task);
+    s_task = GNUNET_SCHEDULER_NO_TASK;
+  }
+  process_requests ();
   return rh;
 }
 
 
-/**
- * Process response with a hostname for a reverse DNS lookup.
- *
- * @param cls our "struct GNUNET_RESOLVER_RequestHandle" context
- * @param msg message with the hostname, NULL on error
- */
-static void
-handle_hostname_response (void *cls, const struct GNUNET_MessageHeader *msg)
-{
-  struct GNUNET_RESOLVER_RequestHandle *rh = cls;
-  uint16_t size;
-  const char *hostname;
-
-  if (msg == NULL)
-    {
-      GNUNET_log (GNUNET_ERROR_TYPE_INFO,
-                  _("Timeout trying to resolve IP address `%s'.\n"),
-		  GNUNET_a2s ((const void*) &rh[1], rh->salen));
-      rh->name_callback (rh->cls, NULL);
-      GNUNET_CLIENT_disconnect (rh->client, GNUNET_NO);
-      GNUNET_free (rh);
-      return;
-    }
-  size = ntohs (msg->size);
-  if (size == sizeof (struct GNUNET_MessageHeader))
-    {
-#if DEBUG_RESOLVER
-      GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
-                  _("Received end message resolving IP address `%s'.\n"),
-		  GNUNET_a2s ((const void*) &rh[1], rh->salen));
-#endif
-      rh->name_callback (rh->cls, NULL);
-      GNUNET_CLIENT_disconnect (rh->client, GNUNET_NO);
-      GNUNET_free (rh);
-      return;
-    }
-  hostname = (const char *) &msg[1];
-  if (hostname[size - sizeof (struct GNUNET_MessageHeader) - 1] != '\0')
-    {
-      GNUNET_break (0);
-      rh->name_callback (rh->cls, NULL);
-      GNUNET_CLIENT_disconnect (rh->client, GNUNET_NO);
-      GNUNET_free (rh);
-      return;
-    }
-#if DEBUG_RESOLVER
-  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
-              _("Resolver returns `%s' for IP `%s'.\n"), 
-	      hostname,
-	      GNUNET_a2s ((const void*) &rh[1], rh->salen));
-#endif
-  rh->name_callback (rh->cls, hostname);
-  GNUNET_CLIENT_receive (rh->client,
-                         &handle_hostname_response,
-                         rh,
-                         GNUNET_TIME_absolute_get_remaining (rh->timeout));
-}
-
-
-
 /**
  * We've been asked to convert an address to a string without
  * a reverse lookup.  Do it.
@@ -569,172 +791,138 @@ numeric_reverse (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
   struct GNUNET_RESOLVER_RequestHandle *rh = cls;
   char *result;
 
-  result = no_resolve ((const struct sockaddr *) &rh[1], rh->salen);
-#if DEBUG_RESOLVER
-  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, _("Resolver returns `%s'.\n"), result);
-#endif
+  result = no_resolve (rh->af, &rh[1], rh->data_len);
+  LOG (GNUNET_ERROR_TYPE_DEBUG, "Resolver returns `%s'.\n", result);
   if (result != NULL)
-    {
-      rh->name_callback (rh->cls, result);
-      GNUNET_free (result);
-    }
+  {
+    rh->name_callback (rh->cls, result);
+    GNUNET_free (result);
+  }
   rh->name_callback (rh->cls, NULL);
   GNUNET_free (rh);
 }
 
 
-
 /**
  * Get an IP address as a string.
  *
- * @param sched scheduler to use
- * @param cfg configuration to use
  * @param sa host address
  * @param salen length of host address
  * @param do_resolve use GNUNET_NO to return numeric hostname
  * @param timeout how long to try resolving
  * @param callback function to call with hostnames
+ *        last callback is NULL when finished
  * @param cls closure for callback
  * @return handle that can be used to cancel the request
  */
 struct GNUNET_RESOLVER_RequestHandle *
-GNUNET_RESOLVER_hostname_get (struct GNUNET_SCHEDULER_Handle *sched,
-                              const struct GNUNET_CONFIGURATION_Handle *cfg,
-                              const struct sockaddr *sa,
-                              socklen_t salen,
+GNUNET_RESOLVER_hostname_get (const struct sockaddr *sa, socklen_t salen,
                               int do_resolve,
                               struct GNUNET_TIME_Relative timeout,
                               GNUNET_RESOLVER_HostnameCallback callback,
                               void *cls)
 {
-  struct GNUNET_CLIENT_Connection *client;
-  struct GNUNET_RESOLVER_GetMessage *msg;
   struct GNUNET_RESOLVER_RequestHandle *rh;
-  char buf[GNUNET_SERVER_MAX_MESSAGE_SIZE];
+  size_t ip_len;
+  const void *ip;
 
-  check_config (cfg);
+  check_config ();
+  switch (sa->sa_family)
+  {
+  case AF_INET:
+    ip_len = sizeof (struct in_addr);
+    ip = &((const struct sockaddr_in*)sa)->sin_addr;
+    break;
+  case AF_INET6:
+    ip_len = sizeof (struct in6_addr);
+    ip = &((const struct sockaddr_in6*)sa)->sin6_addr;
+    break;
+  default:
+    GNUNET_break (0);
+    return NULL;
+  }
   rh = GNUNET_malloc (sizeof (struct GNUNET_RESOLVER_RequestHandle) + salen);
   rh->name_callback = callback;
   rh->cls = cls;
+  rh->af = sa->sa_family;
   rh->timeout = GNUNET_TIME_relative_to_absolute (timeout);
-  rh->sched = sched;
-  rh->salen = salen;
-  memcpy (&rh[1], sa, salen);
-
+  memcpy (&rh[1], ip, ip_len);
+  rh->data_len = ip_len;
+  rh->direction = GNUNET_YES;
+  rh->received_response = GNUNET_NO;
   if (GNUNET_NO == do_resolve)
-    {
-      rh->task = GNUNET_SCHEDULER_add_now (sched,
-					   &numeric_reverse, rh);
-      return rh;
-    }
-  if (salen + sizeof (struct GNUNET_RESOLVER_GetMessage) >
-      GNUNET_SERVER_MAX_MESSAGE_SIZE)
-    {
-      GNUNET_break (0);
-      GNUNET_free (rh);
-      return NULL;
-    }
-  client = GNUNET_CLIENT_connect (sched, "resolver", cfg);
-  if (client == NULL)
-    {
-      GNUNET_free (rh);
-      return NULL;
-    }
-  rh->client = client;
-
-  msg = (struct GNUNET_RESOLVER_GetMessage *) buf;
-  msg->header.size =
-    htons (sizeof (struct GNUNET_RESOLVER_GetMessage) + salen);
-  msg->header.type = htons (GNUNET_MESSAGE_TYPE_RESOLVER_REQUEST);
-  msg->direction = htonl (GNUNET_YES);
-  msg->domain = htonl (sa->sa_family);
-  memcpy (&msg[1], sa, salen);
-#if DEBUG_RESOLVER
-  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
-              _("Resolver requests DNS resolution of IP address.\n"));
-#endif
-  if (GNUNET_OK !=
-      GNUNET_CLIENT_transmit_and_get_response (client,
-                                               &msg->header,
-                                               timeout,
-                                               GNUNET_YES,
-                                               &handle_hostname_response, rh))
-    {
-      GNUNET_CLIENT_disconnect (client, GNUNET_NO);
-      GNUNET_free (rh);
-      return NULL;
-    }
+  {
+    rh->task = GNUNET_SCHEDULER_add_now (&numeric_reverse, rh);
+    return rh;
+  }
+  GNUNET_CONTAINER_DLL_insert_tail (req_head, req_tail, rh);
+  rh->was_queued = GNUNET_YES;
+  if (s_task != GNUNET_SCHEDULER_NO_TASK)
+  {
+    GNUNET_SCHEDULER_cancel (s_task);
+    s_task = GNUNET_SCHEDULER_NO_TASK;
+  }
+  process_requests ();
   return rh;
 }
 
 
 /**
- * Get local hostname
+ * Get local fully qualified af name
  *
- * @param sched scheduler to use
- * @param cfg configuration to use
- * @param callback function to call with addresses
- * @param cls closure for callback
- * @return handle that can be used to cancel the request, NULL on error
+ * @return fqdn
  */
-void
-GNUNET_RESOLVER_local_hostname_get (struct GNUNET_SCHEDULER_Handle *sched,
-                                    const struct GNUNET_CONFIGURATION_Handle *cfg,
-                                    GNUNET_RESOLVER_HostnameCallback callback,
-                                    void *cls)
+char *
+GNUNET_RESOLVER_local_fqdn_get ()
 {
+  struct hostent *host;
+  char hostname[GNUNET_OS_get_hostname_max_length () + 1];
 
-  char hostname[GNUNET_OS_get_hostname_max_length() + 1];
-
-  check_config (cfg);
   if (0 != gethostname (hostname, sizeof (hostname) - 1))
-    {
-      GNUNET_log_strerror (GNUNET_ERROR_TYPE_ERROR |
-                           GNUNET_ERROR_TYPE_BULK, "gethostname");
-      return;
-    }
-#if DEBUG_RESOLVER
-  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
-              _("Resolving our hostname `%s'\n"), hostname);
-#endif
-  callback (cls, hostname);
+  {
+    LOG_STRERROR (GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+                  "gethostname");
+    return NULL;
+  }
+  LOG (GNUNET_ERROR_TYPE_DEBUG, "Resolving our FQDN `%s'\n", hostname);
+  host = gethostbyname (hostname);
+  if (NULL == host)
+  {
+    LOG (GNUNET_ERROR_TYPE_ERROR, _("Could not resolve our FQDN : %s\n"),
+         hstrerror (h_errno));
+    return NULL;
+  }
+  return GNUNET_strdup (host->h_name);
 }
 
+
 /**
  * Looking our own hostname.
  *
- * @param sched scheduler to use
- * @param cfg configuration to use
- * @param domain AF_INET or AF_INET6; use AF_UNSPEC for "any"
+ * @param af AF_INET or AF_INET6; use AF_UNSPEC for "any"
  * @param callback function to call with addresses
  * @param cls closure for callback
  * @param timeout how long to try resolving
  * @return handle that can be used to cancel the request, NULL on error
  */
 struct GNUNET_RESOLVER_RequestHandle *
-GNUNET_RESOLVER_hostname_resolve (struct GNUNET_SCHEDULER_Handle *sched,
-                                  const struct GNUNET_CONFIGURATION_Handle
-                                  *cfg, int domain,
+GNUNET_RESOLVER_hostname_resolve (int af,
                                   struct GNUNET_TIME_Relative timeout,
                                   GNUNET_RESOLVER_AddressCallback callback,
                                   void *cls)
 {
-  char hostname[GNUNET_OS_get_hostname_max_length() + 1];
+  char hostname[GNUNET_OS_get_hostname_max_length () + 1];
 
-  check_config (cfg);
   if (0 != gethostname (hostname, sizeof (hostname) - 1))
-    {
-      GNUNET_log_strerror (GNUNET_ERROR_TYPE_ERROR |
-                           GNUNET_ERROR_TYPE_BULK, "gethostname");
-      return NULL;
-    }
-#if DEBUG_RESOLVER
-  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
-              _("Resolving our hostname `%s'\n"), hostname);
-#endif
-  return GNUNET_RESOLVER_ip_get (sched,
-                                 cfg, hostname, domain, timeout, callback,
-                                 cls);
+  {
+    LOG_STRERROR (GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+                  "gethostname");
+    return NULL;
+  }
+  LOG (GNUNET_ERROR_TYPE_DEBUG,
+       "Resolving our hostname `%s'\n",
+       hostname);
+  return GNUNET_RESOLVER_ip_get (hostname, af, timeout, callback, cls);
 }
 
 
@@ -744,18 +932,26 @@ GNUNET_RESOLVER_hostname_resolve (struct GNUNET_SCHEDULER_Handle *sched,
  * been completed (i.e, the callback has been called to
  * signal timeout or the final result).
  *
- * @param h handle of request to cancel
+ * @param rh handle of request to cancel
  */
 void
-GNUNET_RESOLVER_request_cancel (struct GNUNET_RESOLVER_RequestHandle *h)
+GNUNET_RESOLVER_request_cancel (struct GNUNET_RESOLVER_RequestHandle *rh)
 {
-  if (h->client != NULL)
-    GNUNET_CLIENT_disconnect (h->client, GNUNET_NO);
-  if (h->task != GNUNET_SCHEDULER_NO_TASK)
-    GNUNET_SCHEDULER_cancel (h->sched, h->task);
-  GNUNET_free (h);
+  if (rh->task != GNUNET_SCHEDULER_NO_TASK)
+  {
+    GNUNET_SCHEDULER_cancel (rh->task);
+    rh->task = GNUNET_SCHEDULER_NO_TASK;
+  }
+  if (rh->was_transmitted == GNUNET_NO)
+  {
+    if (rh->was_queued == GNUNET_YES)
+      GNUNET_CONTAINER_DLL_remove (req_head, req_tail, rh);
+    GNUNET_free (rh);
+    return;
+  }
+  GNUNET_assert (rh->was_transmitted == GNUNET_YES);
+  rh->was_transmitted = GNUNET_SYSERR;  /* mark as cancelled */
 }
 
 
-
 /* end of resolver_api.c */