10 files changed, 266 insertions, 85 deletions

diff --git a/src/dhtu/Makefile.am b/src/dhtu/Makefile.am
index 72b422812..f4b968526 100644
--- a/src/dhtu/Makefile.am
+++ b/src/dhtu/Makefile.am
@@ -11,6 +11,7 @@ if USE_COVERAGE
 endif
 
 plugin_LTLIBRARIES = \
+  libgnunet_plugin_dhtu_gnunet.la \
   libgnunet_plugin_dhtu_ip.la
 
 libgnunet_plugin_dhtu_ip_la_SOURCES = \
@@ -22,3 +23,14 @@ libgnunet_plugin_dhtu_ip_la_LIBADD = \
 libgnunet_plugin_dhtu_ip_la_LDFLAGS = \
  $(GN_PLUGIN_LDFLAGS)
 
+
+
+libgnunet_plugin_dhtu_gnunet_la_SOURCES = \
+  plugin_dhtu_gnunet.c
+libgnunet_plugin_dhtu_gnunet_la_LIBADD = \
+  $(top_builddir)/src/core/libgnunetcore.la \
+  $(top_builddir)/src/util/libgnunetutil.la \
+  $(XLIBS) \
+  $(LTLIBINTL)
+libgnunet_plugin_dhtu_gnunet_la_LDFLAGS = \
+ $(GN_PLUGIN_LDFLAGS)
diff --git a/src/dhtu/plugin_dhtu_gnunet.c b/src/dhtu/plugin_dhtu_gnunet.c
index d6cd75242..ccd329e8e 100644
--- a/src/dhtu/plugin_dhtu_gnunet.c
+++ b/src/dhtu/plugin_dhtu_gnunet.c
@@ -21,11 +21,44 @@
 /**
  * @author Christian Grothoff
  *
- * @file plugin_dhtu_ip.c
+ * @file plugin_dhtu_gnunet.c
  * @brief plain IP based DHT network underlay
  */
 #include "platform.h"
-#incluce "gnunet_dhtu_plugin.h"
+#include "gnunet_dhtu_plugin.h"
+#include "gnunet_core_service.h"
+
+/**
+ * Handle for a private key used by this underlay.
+ */
+struct GNUNET_DHTU_PrivateKey
+{
+  /**
+   * GNUnet uses eddsa for peers.
+   */
+  struct GNUNET_CRYPTO_EddsaPrivateKey eddsa_priv;
+
+};
+
+
+/**
+ * Handle for a public key used by this underlay.
+ */
+struct PublicKey
+{
+
+  /**
+   * Header.
+   */
+  struct GNUNET_DHTU_PublicKey header;
+
+  /**
+   * GNUnet uses eddsa for peers.
+   */
+  struct GNUNET_CRYPTO_EddsaPublicKey eddsa_pub;
+
+};
+
 
 /**
  * Opaque handle that the underlay offers for our address to be used when
@@ -47,7 +80,7 @@ struct GNUNET_DHTU_Source
  */
 struct GNUNET_DHTU_Target
 {
-  
+
   /**
    * Application context for this target.
    */
@@ -94,23 +127,20 @@ struct GNUNET_DHTU_PreferenceHandle
 
 
 /**
- * Opaque handle for a private key used by this underlay.
- */
-struct GNUNET_DHTU_PrivateKey
-{
-  /* we are IP, we do not do crypto */
-};
-
-
-/**
  * Closure for all plugin functions.
  */
 struct Plugin
 {
-  /** 
+  /**
    * Callbacks into the DHT.
    */
   struct GNUNET_DHTU_PluginEnvironment *env;
+
+  /**
+   * Handle to the CORE service.
+   */
+  struct GNUNET_CORE_Handle *core;
+  
 };
 
 
@@ -126,10 +156,17 @@ struct Plugin
 static ssize_t
 ip_sign (void *cls,
          const struct GNUNET_DHTU_PrivateKey *pk,
-         const struct GNUNET_DHTU_SignaturePurpose *purpose,
+         const struct GNUNET_CRYPTO_EccSignaturePurpose *purpose,
          void **sig)
 {
-  return 0;
+  struct GNUNET_CRYPTO_EddsaSignature *es;
+
+  es = GNUNET_new (struct GNUNET_CRYPTO_EddsaSignature);
+  GNUNET_CRYPTO_eddsa_sign_ (&pk->eddsa_priv,
+                             purpose,
+                             es);
+  *sig = es;
+  return sizeof (*es);
 }
 
 
@@ -148,11 +185,31 @@ ip_sign (void *cls,
 static enum GNUNET_GenericReturnValue
 ip_verify (void *cls,
            const struct GNUNET_DHTU_PublicKey *pk,
-           const struct GNUNET_DHTU_SignaturePurpose *purpose,
+           const struct GNUNET_CRYPTO_EccSignaturePurpose *purpose,
            const void *sig,
            size_t sig_size)
 {
-  return GNUNET_NO;
+  const struct GNUNET_CRYPTO_EddsaSignature *es = sig;
+  const struct PublicKey *pub;
+
+  GNUNET_assert (sizeof (struct PublicKey) ==
+                 ntohs (pk->size));
+  pub = (const struct PublicKey *) pk;
+  if (sizeof (*es) != sig_size)
+  {
+    GNUNET_break_op (0);
+    return GNUNET_SYSERR;
+  }
+  if (GNUNET_OK !=
+      GNUNET_CRYPTO_eddsa_verify_ (ntohl (purpose->purpose),
+                                   purpose,
+                                   es,
+                                   &pub->eddsa_pub))
+  {
+    GNUNET_break_op (0);
+    return GNUNET_SYSERR;
+  }
+  return GNUNET_OK;
 }
 
 
@@ -174,7 +231,7 @@ ip_try_connect (void *cls,
  * Request underlay to keep the connection to @a target alive if possible.
  * Hold may be called multiple times to express a strong preference to
  * keep a connection, say because a @a target is in multiple tables.
- * 
+ *
  * @param cls closure
  * @param target connection to keep alive
  */
@@ -196,7 +253,7 @@ ip_hold (void *cls,
 
 /**
  * Do no long request underlay to keep the connection alive.
- * 
+ *
  * @param cls closure
  * @param target connection to keep alive
  */
@@ -204,7 +261,7 @@ static void
 ip_drop (struct GNUNET_DHTU_PreferenceHandle *ph)
 {
   struct GNUNET_DHTU_Target *target = ph->target;
-  
+
   GNUNET_CONTAINER_DLL_remove (target->ph_head,
                                target->ph_tail,
                                ph);
@@ -225,7 +282,7 @@ ip_drop (struct GNUNET_DHTU_PreferenceHandle *ph)
  * @param msg_size number of bytes in @a msg
  * @param finished_cb function called once transmission is done
  *        (not called if @a target disconnects, then only the
- *         disconnect_cb is called). 
+ *         disconnect_cb is called).
  * @param finished_cb_cls closure for @a finished_cb
  */
 static void
@@ -240,6 +297,60 @@ ip_send (void *cls,
 }
 
 
+
+/**
+ * Method called whenever a given peer connects.
+ *
+ * @param cls closure
+ * @param peer peer identity this notification is about
+ * @return closure associated with @a peer. given to mq callbacks and
+ *         #GNUNET_CORE_DisconnectEventHandler
+ */
+static void *
+core_connect_cb (void *cls,
+                 const struct GNUNET_PeerIdentity *peer,
+                 struct GNUNET_MQ_Handle *mq)
+{
+  return NULL;
+}
+
+
+/**
+ * Method called whenever a peer disconnects.
+ *
+ * @param cls closure
+ * @param peer peer identity this notification is about
+ * @param peer_cls closure associated with peer. given in
+ *        #GNUNET_CORE_ConnectEventHandler
+ */
+static void
+core_disconnect_cb (void *cls,
+                    const struct GNUNET_PeerIdentity *peer,
+                    void *peer_cls)
+{
+}
+
+
+/**
+ * Function called after #GNUNET_CORE_connect has succeeded (or failed
+ * for good).  Note that the private key of the peer is intentionally
+ * not exposed here; if you need it, your process should try to read
+ * the private key file directly (which should work if you are
+ * authorized...).  Implementations of this function must not call
+ * #GNUNET_CORE_disconnect (other than by scheduling a new task to
+ * do this later).
+ *
+ * @param cls closure
+ * @param my_identity ID of this peer, NULL if we failed
+ */
+static void
+core_init_cb (void *cls,
+              const struct GNUNET_PeerIdentity *my_identity)
+{
+  struct Plugin *plugin = cls;
+}
+
+
 /**
  * Entry point for the plugin.
  *
@@ -252,6 +363,9 @@ libgnunet_plugin_dhtu_ip_init (void *cls)
   struct GNUNET_DHTU_PluginEnvironment *env = cls;
   struct GNUNET_DHTU_PluginFunctions *api;
   struct Plugin *plugin;
+  struct GNUNET_MQ_MessageHandler handlers[] = {
+    GNUNET_MQ_handler_end ()
+  };
 
   plugin = GNUNET_new (struct Plugin);
   plugin->env = env;
@@ -263,6 +377,12 @@ libgnunet_plugin_dhtu_ip_init (void *cls)
   api->hold = &ip_hold;
   api->drop = &ip_drop;
   api->send = &ip_send;
+  plugin->core = GNUNET_CORE_connect (env->cfg,
+                                      plugin,
+                                      &core_init_cb,
+                                      &core_connect_cb,
+                                      &core_disconnect_cb,
+                                      handlers);
   return api;
 }
 
@@ -279,6 +399,7 @@ libgnunet_plugin_dhtu_gnunet_done (void *cls)
   struct GNUNET_DHTU_PluginFunctions *api = cls;
   struct Plugin *plugin = api->cls;
 
+  GNUNET_CORE_disconnect (plugin->core);
   GNUNET_free (plugin);
   GNUNET_free (api);
   return NULL;
diff --git a/src/dhtu/plugin_dhtu_ip.c b/src/dhtu/plugin_dhtu_ip.c
index 8593a69ef..ae35adb37 100644
--- a/src/dhtu/plugin_dhtu_ip.c
+++ b/src/dhtu/plugin_dhtu_ip.c
@@ -240,7 +240,7 @@ struct Plugin
 static ssize_t
 ip_sign (void *cls,
          const struct GNUNET_DHTU_PrivateKey *pk,
-         const struct GNUNET_DHTU_SignaturePurpose *purpose,
+         const struct GNUNET_CRYPTO_EccSignaturePurpose *purpose,
          void **sig)
 {
   return 0;
@@ -262,7 +262,7 @@ ip_sign (void *cls,
 static enum GNUNET_GenericReturnValue
 ip_verify (void *cls,
            const struct GNUNET_DHTU_PublicKey *pk,
-           const struct GNUNET_DHTU_SignaturePurpose *purpose,
+           const struct GNUNET_CRYPTO_EccSignaturePurpose *purpose,
            const void *sig,
            size_t sig_size)
 {
diff --git a/src/include/gnunet_common.h b/src/include/gnunet_common.h
index ca3ddceaa..4472d3ee8 100644
--- a/src/include/gnunet_common.h
+++ b/src/include/gnunet_common.h
@@ -151,10 +151,10 @@ enum GNUNET_GenericReturnValue
  */
 
 #if __BYTE_ORDER == __LITTLE_ENDIAN
-#if defined(__linux__)
-#define BYTE_SWAP_16(x) __bswap_16 (x)
-#define BYTE_SWAP_32(x) __bswap_32 (x)
-#define BYTE_SWAP_64(x) __bswap_64 (x)
+#ifdef HAVE_BYTESWAP_H
+#define BYTE_SWAP_16(x) bswap_16 (x)
+#define BYTE_SWAP_32(x) bswap_32 (x)
+#define BYTE_SWAP_64(x) bswap_64 (x)
 #else
 #define BYTE_SWAP_16(x) ((((x) & 0x00ff) << 8) | (((x) & 0xff00) >> 8))
 
diff --git a/src/include/gnunet_dhtu_plugin.h b/src/include/gnunet_dhtu_plugin.h
index df9729a23..e65318fb5 100644
--- a/src/include/gnunet_dhtu_plugin.h
+++ b/src/include/gnunet_dhtu_plugin.h
@@ -75,42 +75,18 @@ struct GNUNET_DHTU_PublicKey
 
   /* followed by size-2 bytes of the actual public key */
 };
-  
+
 
 /**
  * Hash used by the DHT for keys and peers.
  */
 struct GNUNET_DHTU_Hash
 {
-  
-  /**
-   * For now, use a 512 bit hash. (To be discussed).
-   */ 
-  struct GNUNET_HashCode hc;
-};
-
 
-/**
- * @brief header of what an DHTU signature signs
- *        this must be followed by "size - 8" bytes of
- *        the actual signed data
- */
-struct GNUNET_DHTU_SignaturePurpose
-{
   /**
-   * How many bytes does this signature sign?
-   * (including this purpose header); in network
-   * byte order (!).
-   */
-  uint32_t size GNUNET_PACKED;
-
-  /**
-   * What does this signature vouch for?  This
-   * must contain a GNUNET_SIGNATURE_PURPOSE_XXX
-   * constant (from gnunet_signatures.h).  In
-   * network byte order!
+   * For now, use a 512 bit hash. (To be discussed).
    */
-  uint32_t purpose GNUNET_PACKED;
+  struct GNUNET_HashCode hc;
 };
 
 
@@ -131,7 +107,7 @@ struct GNUNET_DHTU_PluginEnvironment
    */
   void *cls;
 
-  /** 
+  /**
    * Function to call with new addresses of this peer.
    *
    * @param cls the closure
@@ -151,7 +127,7 @@ struct GNUNET_DHTU_PluginEnvironment
                     struct GNUNET_DHTU_Source *source,
                     void **ctx);
 
-  /** 
+  /**
    * Function to call with expired addresses of this peer.
    *
    * @param[in] ctx storage space used by the DHT in association with this address
@@ -160,7 +136,7 @@ struct GNUNET_DHTU_PluginEnvironment
   (*address_del_cb)(void *ctx);
 
   /**
-   * We have a new estimate on the size of the underlay. 
+   * We have a new estimate on the size of the underlay.
    *
    * @param cls closure
    * @param timestamp time when the estimate was received from the server (or created by the server)
@@ -172,7 +148,7 @@ struct GNUNET_DHTU_PluginEnvironment
                      struct GNUNET_TIME_Absolute timestamp,
                      double logestimate,
                      double std_dev);
-  
+
   /**
    * Function to call when we connect to a peer and can henceforth transmit to
    * that peer.
@@ -208,7 +184,7 @@ struct GNUNET_DHTU_PluginEnvironment
    * @param cls the closure
    * @param origin where the message originated from
    * @param[in,out] tctx ctx of target address where we received the message from
-   * @param[in,out] sctx ctx of our own source address at which we received the message 
+   * @param[in,out] sctx ctx of our own source address at which we received the message
    * @param message the message we received @param message_size number of
    * bytes in @a message
    */
@@ -244,7 +220,7 @@ struct GNUNET_DHTU_PluginFunctions
   ssize_t
   (*sign)(void *cls,
           const struct GNUNET_DHTU_PrivateKey *pk,
-          const struct GNUNET_DHTU_SignaturePurpose *purpose,
+          const struct GNUNET_CRYPTO_EccSignaturePurpose *purpose,
           void **sig);
 
   /**
@@ -262,7 +238,7 @@ struct GNUNET_DHTU_PluginFunctions
   enum GNUNET_GenericReturnValue
   (*verify)(void *cls,
             const struct GNUNET_DHTU_PublicKey *pk,
-            const struct GNUNET_DHTU_SignaturePurpose *purpose,
+            const struct GNUNET_CRYPTO_EccSignaturePurpose *purpose,
             const void *sig,
             size_t sig_size);
 
@@ -281,7 +257,7 @@ struct GNUNET_DHTU_PluginFunctions
    * Request underlay to keep the connection to @a target alive if possible.
    * Hold may be called multiple times to express a strong preference to
    * keep a connection, say because a @a target is in multiple tables.
-   * 
+   *
    * @param cls closure
    * @param target connection to keep alive
    */
@@ -291,13 +267,13 @@ struct GNUNET_DHTU_PluginFunctions
 
   /**
    * Do no long request underlay to keep the connection alive.
-   * 
+   *
    * @param cls closure
    * @param target connection to keep alive
    */
   void
   (*drop)(struct GNUNET_DHTU_PreferenceHandle *ph);
-  
+
   /**
    * Send message to some other participant over the network.  Note that
    * sending is not guaranteeing that the other peer actually received the
@@ -310,7 +286,7 @@ struct GNUNET_DHTU_PluginFunctions
    * @param msg_size number of bytes in @a msg
    * @param finished_cb function called once transmission is done
    *        (not called if @a target disconnects, then only the
-   *         disconnect_cb is called). 
+   *         disconnect_cb is called).
    * @param finished_cb_cls closure for @a finished_cb
    */
   void
@@ -320,7 +296,7 @@ struct GNUNET_DHTU_PluginFunctions
            size_t msg_size,
            GNUNET_SCHEDULER_TaskCallback finished_cb,
            void *finished_cb_cls);
- 
+
 };
 
 
diff --git a/src/include/gnunet_hello_lib.h b/src/include/gnunet_hello_lib.h
index fff0045aa..74eca999d 100644
--- a/src/include/gnunet_hello_lib.h
+++ b/src/include/gnunet_hello_lib.h
@@ -268,9 +268,10 @@ GNUNET_HELLO_add_address (const struct GNUNET_HELLO_Address *address,
  * @return number of bytes written or 0, #GNUNET_SYSERR to signal the
  *         end of the iteration.
  */
-typedef ssize_t (*GNUNET_HELLO_GenerateAddressListCallback) (void *cls,
-                                                             size_t max,
-                                                             void *buf);
+typedef ssize_t
+(*GNUNET_HELLO_GenerateAddressListCallback) (void *cls,
+                                             size_t max,
+                                             void *buf);
 
 
 /**
diff --git a/src/include/gnunet_mq_lib.h b/src/include/gnunet_mq_lib.h
index 37bba8c1b..765647a98 100644
--- a/src/include/gnunet_mq_lib.h
+++ b/src/include/gnunet_mq_lib.h
@@ -331,9 +331,10 @@ typedef int (*GNUNET_MQ_MessageValidationCallback) (
  * @param msg the message to send
  * @param impl_state state of the implementation
  */
-typedef void (*GNUNET_MQ_SendImpl) (struct GNUNET_MQ_Handle *mq,
-                                    const struct GNUNET_MessageHeader *msg,
-                                    void *impl_state);
+typedef void
+(*GNUNET_MQ_SendImpl) (struct GNUNET_MQ_Handle *mq,
+                       const struct GNUNET_MessageHeader *msg,
+                       void *impl_state);
 
 
 /**
@@ -345,8 +346,9 @@ typedef void (*GNUNET_MQ_SendImpl) (struct GNUNET_MQ_Handle *mq,
  * @param mq the message queue to destroy
  * @param impl_state state of the implementation
  */
-typedef void (*GNUNET_MQ_DestroyImpl) (struct GNUNET_MQ_Handle *mq,
-                                       void *impl_state);
+typedef void
+(*GNUNET_MQ_DestroyImpl) (struct GNUNET_MQ_Handle *mq,
+                          void *impl_state);
 
 
 /**
@@ -355,8 +357,9 @@ typedef void (*GNUNET_MQ_DestroyImpl) (struct GNUNET_MQ_Handle *mq,
  * @param mq message queue
  * @param impl_state state specific to the implementation
  */
-typedef void (*GNUNET_MQ_CancelImpl) (struct GNUNET_MQ_Handle *mq,
-                                      void *impl_state);
+typedef void
+(*GNUNET_MQ_CancelImpl) (struct GNUNET_MQ_Handle *mq,
+                         void *impl_state);
 
 
 /**
@@ -368,7 +371,9 @@ typedef void (*GNUNET_MQ_CancelImpl) (struct GNUNET_MQ_Handle *mq,
  * @param cls closure
  * @param error error code
  */
-typedef void (*GNUNET_MQ_ErrorHandler) (void *cls, enum GNUNET_MQ_Error error);
+typedef void
+(*GNUNET_MQ_ErrorHandler) (void *cls,
+                           enum GNUNET_MQ_Error error);
 
 
 /**
diff --git a/src/include/gnunet_transport_service.h b/src/include/gnunet_transport_service.h
index d190eff92..545bb28d2 100644
--- a/src/include/gnunet_transport_service.h
+++ b/src/include/gnunet_transport_service.h
@@ -115,7 +115,8 @@ struct GNUNET_TRANSPORT_AddressToStringContext;
  *        if #GNUNET_NO: address was invalid (or not supported)
  *        if #GNUNET_SYSERR: communication error (IPC error)
  */
-typedef void (*GNUNET_TRANSPORT_AddressToStringCallback) (void *cls,
+typedef void
+(*GNUNET_TRANSPORT_AddressToStringCallback) (void *cls,
                                                           const char *address,
                                                           int res);
 
@@ -326,7 +327,8 @@ struct GNUNET_TRANSPORT_PeerMonitoringContext;
  * @param state current state this peer is in
  * @param state_timeout timeout for the current state of the peer
  */
-typedef void (*GNUNET_TRANSPORT_PeerIterateCallback) (
+typedef void
+(*GNUNET_TRANSPORT_PeerIterateCallback) (
   void *cls,
   const struct GNUNET_PeerIdentity *peer,
   const struct GNUNET_HELLO_Address *address,
@@ -394,7 +396,8 @@ struct GNUNET_TRANSPORT_Blacklist;
  * @param pid peer to approve or disapproave
  * @return #GNUNET_OK if the connection is allowed, #GNUNET_SYSERR if not
  */
-typedef int (*GNUNET_TRANSPORT_BlacklistCallback) (
+typedef int
+(*GNUNET_TRANSPORT_BlacklistCallback) (
   void *cls,
   const struct GNUNET_PeerIdentity *pid);
 
@@ -541,7 +544,8 @@ struct GNUNET_TRANSPORT_SessionInfo
  *        NULL with @a session being non-NULL if the monitor
  *        was being cancelled while sessions were active
  */
-typedef void (*GNUNET_TRANSPORT_SessionMonitorCallback) (
+typedef void
+(*GNUNET_TRANSPORT_SessionMonitorCallback) (
   void *cls,
   struct GNUNET_TRANSPORT_PluginSession *session,
   void **session_ctx,
@@ -593,7 +597,8 @@ struct GNUNET_TRANSPORT_CoreHandle;
  * @param mq message queue to use to transmit to @a peer
  * @return closure to use in MQ handlers
  */
-typedef void *(*GNUNET_TRANSPORT_NotifyConnect) (
+typedef void *
+(*GNUNET_TRANSPORT_NotifyConnect) (
   void *cls,
   const struct GNUNET_PeerIdentity *peer,
   struct GNUNET_MQ_Handle *mq);
@@ -610,7 +615,8 @@ typedef void *(*GNUNET_TRANSPORT_NotifyConnect) (
  * @param handlers_cls closure of the handlers, was returned from the
  *                    connect notification callback
  */
-typedef void (*GNUNET_TRANSPORT_NotifyDisconnect) (
+typedef void
+(*GNUNET_TRANSPORT_NotifyDisconnect) (
   void *cls,
   const struct GNUNET_PeerIdentity *peer,
   void *handler_cls);
@@ -632,7 +638,8 @@ typedef void (*GNUNET_TRANSPORT_NotifyDisconnect) (
  * @param handlers_cls closure of the handlers, was returned from the
  *                    connect notification callback
  */
-typedef void (*GNUNET_TRANSPORT_NotifyExcessBandwidth) (
+typedef void
+(*GNUNET_TRANSPORT_NotifyExcessBandwidth) (
   void *cls,
   const struct GNUNET_PeerIdentity *neighbour,
   void *handlers_cls);
diff --git a/src/transport/test_transport_port_forward.c b/src/transport/test_transport_port_forward.c
index b0f0b113e..d3233c2da 100644
--- a/src/transport/test_transport_port_forward.c
+++ b/src/transport/test_transport_port_forward.c
@@ -21,7 +21,7 @@
 /**
  * @file transport/test_transport_port_forward.c
  * @brief Test case executing a script which sends a test UDP message from a nated peer
- *        to a gloabl known peer. There is a tcp port forwarding in place towards the
+ *        to a global known peer. There is a tcp port forwarding in place towards the
  *        natted peer to test the backchannel functionality of the TNG service.
  * @author t3sserakt
  */
diff --git a/src/util/gnunet-config.c b/src/util/gnunet-config.c
index 797de0b0d..2ca78577e 100644
--- a/src/util/gnunet-config.c
+++ b/src/util/gnunet-config.c
@@ -36,6 +36,25 @@ static char *backend_check;
 
 
 /**
+ * If printing the value of CFLAGS has been requested.
+ */
+static int cflags;
+
+
+/**
+ * If printing the value of LIBS has been requested.
+ */
+static int libs;
+
+
+/**
+ * If printing the value of PREFIX has been requested.
+ */
+static int prefix;
+
+
+/**
+ * Print each option in a given section.
  * Main task to run to perform operations typical for
  * gnunet-config as per the configuration settings
  * given in @a cls.
@@ -54,6 +73,28 @@ run (void *cls,
 {
   struct GNUNET_CONFIGURATION_ConfigSettings *cs = cls;
 
+  if (1 == cflags || 1 == libs || 1 == prefix)
+  {
+    char *prefixdir = GNUNET_OS_installation_get_path (GNUNET_OS_IPK_PREFIX);
+    char *libdir = GNUNET_OS_installation_get_path (GNUNET_OS_IPK_LIBDIR);
+
+    if (1 == cflags)
+    {
+      fprintf (stdout, "-I%sinclude\n", prefixdir);
+    }
+    if (1 == libs)
+    {
+      fprintf (stdout, "-L%s -lgnunetutil\n", libdir);
+    }
+    if (1 == prefix)
+    {
+      fprintf (stdout, "%s\n", prefixdir);
+    }
+    cs->global_ret = 0;
+    GNUNET_free (prefixdir);
+    GNUNET_free (libdir);
+    return;
+  }
   if (NULL != backend_check)
   {
     char *name;
@@ -97,6 +138,24 @@ main (int argc,
         gettext_noop (
           "test if the current installation supports the specified BACKEND"),
         &backend_check)),
+    GNUNET_GETOPT_option_flag (
+      'C',
+      "cflags",
+      gettext_noop (
+        "Provide an appropriate value for CFLAGS to applications building on top of GNUnet"),
+      &cflags),
+    GNUNET_GETOPT_option_flag (
+      'j',
+      "libs",
+      gettext_noop (
+        "Provide an appropriate value for LIBS to applications building on top of GNUnet"),
+      &libs),
+    GNUNET_GETOPT_option_flag (
+      'p',
+      "prefix",
+      gettext_noop (
+        "Provide the path under which GNUnet was installed"),
+      &prefix),
     GNUNET_CONFIGURATION_CONFIG_OPTIONS (&cs),
     GNUNET_GETOPT_OPTION_END
   };