-doxygen, following naming conventions
[oweals/gnunet.git] / src / vpn / gnunet-service-vpn.c
index 4db343f6ade3063b62ae14c99a6ef278df658789..030816797cf80c8dfab729bed6213c756b2b9207 100644 (file)
  *        IP traffic received on those IPs via the GNUnet mesh 
  * @author Philipp Toelke
  * @author Christian Grothoff
+ *
+ * TODO:
+ * - keep multiple peers/mesh tunnels ready as alternative exits /
+ *   recover from tunnel-to-exit failure gracefully
  */
 #include "platform.h"
 #include "gnunet_util_lib.h"
@@ -35,6 +39,7 @@
 #include "gnunet_statistics_service.h"
 #include "gnunet_constants.h"
 #include "gnunet_tun_lib.h"
+#include "gnunet_regex_service.h"
 #include "vpn.h"
 #include "exit.h"
 
@@ -45,6 +50,8 @@
 #define MAX_MESSAGE_QUEUE_SIZE 4
 
 
+#define PORT_VPN 42
+
 /**
  * State we keep for each of our tunnels.
  */
@@ -62,7 +69,7 @@ struct DestinationEntry
    * Key under which this entry is in the 'destination_map' (only valid
    * if 'heap_node != NULL').
    */
-  GNUNET_HashCode key;
+  struct GNUNET_HashCode key;
 
   /**
    * Pre-allocated tunnel for this destination, or NULL for none.
@@ -75,8 +82,8 @@ struct DestinationEntry
   struct GNUNET_CONTAINER_HeapNode *heap_node;
 
   /**
-   * GNUNET_NO if this is a tunnel to an Internet-exit,
-   * GNUNET_YES if this tunnel is to a service.
+   * #GNUNET_NO if this is a tunnel to an Internet-exit,
+   * #GNUNET_YES if this tunnel is to a service.
    */
   int is_service;
 
@@ -91,7 +98,7 @@ struct DestinationEntry
       /**
        * The description of the service (only used for service tunnels).
        */
-      GNUNET_HashCode service_descriptor;
+      struct GNUNET_HashCode service_descriptor;
 
       /**
        * Peer offering the service.
@@ -170,6 +177,11 @@ struct TunnelState
    */
   struct GNUNET_MESH_Tunnel *tunnel;
 
+  /**
+   * Active query with REGEX to locate exit.
+   */
+  struct GNUNET_REGEX_Search *search;
+
   /**
    * Active transmission handle, NULL for none.
    */
@@ -284,6 +296,11 @@ struct TunnelState
 };
 
 
+/**
+ * Return value from 'main'.
+ */
+static int global_ret;
+
 /**
  * Configuration we use.
  */
@@ -366,7 +383,7 @@ static unsigned long long max_tunnel_mappings;
 static void
 get_destination_key_from_ip (int af,
                             const void *address,
-                            GNUNET_HashCode *key)
+                            struct GNUNET_HashCode *key)
 {
   switch (af)
   {
@@ -406,11 +423,11 @@ get_tunnel_key_from_ips (int af,
                         uint16_t source_port,
                         const void *destination_ip,
                         uint16_t destination_port,
-                        GNUNET_HashCode *key)
+                        struct GNUNET_HashCode *key)
 {
   char *off;
 
-  memset (key, 0, sizeof (GNUNET_HashCode));
+  memset (key, 0, sizeof (struct GNUNET_HashCode));
   /* the GNUnet hashmap only uses the first sizeof(unsigned int) of the hash,
      so we put the ports in there (and hope for few collisions) */
   off = (char*) key;
@@ -437,7 +454,7 @@ get_tunnel_key_from_ips (int af,
     break;
   }
   memcpy (off, &protocol, sizeof (uint8_t));
-  off += sizeof (uint8_t);  
+  /* off += sizeof (uint8_t);  */
 }
 
 
@@ -455,7 +472,7 @@ send_client_reply (struct GNUNET_SERVER_Client *client,
                   int result_af,
                   const void *addr)
 {
-  char buf[sizeof (struct RedirectToIpResponseMessage) + sizeof (struct in6_addr)];
+  char buf[sizeof (struct RedirectToIpResponseMessage) + sizeof (struct in6_addr)] GNUNET_ALIGN;
   struct RedirectToIpResponseMessage *res;
   size_t rlen;
 
@@ -496,7 +513,7 @@ send_client_reply (struct GNUNET_SERVER_Client *client,
 static void
 free_tunnel_state (struct TunnelState *ts)
 {
-  GNUNET_HashCode key;
+  struct GNUNET_HashCode key;
   struct TunnelMessageQueueEntry *tnq;
   struct GNUNET_MESH_Tunnel *tunnel;
 
@@ -514,11 +531,6 @@ free_tunnel_state (struct TunnelState *ts)
     GNUNET_free (tnq);
   }
   GNUNET_assert (0 == ts->tmq_length);
-  if (NULL != ts->client)
-  {
-    GNUNET_SERVER_client_drop (ts->client);
-    ts->client = NULL;
-  }
   if (NULL != ts->th)
   {
     GNUNET_MESH_notify_transmit_ready_cancel (ts->th);
@@ -530,6 +542,11 @@ free_tunnel_state (struct TunnelState *ts)
     ts->tunnel = NULL;
     GNUNET_MESH_tunnel_destroy (tunnel);
   }
+  if (NULL != ts->search)
+  {
+    GNUNET_REGEX_search_cancel (ts->search);
+    ts->search = NULL;
+  }
   if (GNUNET_SCHEDULER_NO_TASK != ts->destroy_task)
   {
     GNUNET_SCHEDULER_cancel (ts->destroy_task);
@@ -564,8 +581,8 @@ free_tunnel_state (struct TunnelState *ts)
 /**
  * Destroy the mesh tunnel.
  *
- * @param cls the 'struct TunnelState' with the tunnel to destroy
- * @param ts schedule context
+ * @param cls the `struct TunnelState` with the tunnel to destroy
+ * @param tc scheduler context
  */
 static void
 destroy_tunnel_task (void *cls,
@@ -586,13 +603,15 @@ destroy_tunnel_task (void *cls,
 /**
  * Method called whenever a peer has disconnected from the tunnel.
  *
+ * FIXME merge with inbound_cleaner
+ * 
  * @param cls closure
  * @param peer peer identity the tunnel stopped working with
  */
-static void
+void
 tunnel_peer_disconnect_handler (void *cls,
                                const struct
-                               GNUNET_PeerIdentity * peer)
+                               GNUNET_PeerIdentity *peer)
 {
   struct TunnelState *ts = cls;
 
@@ -600,7 +619,7 @@ tunnel_peer_disconnect_handler (void *cls,
              "Peer %s disconnected from tunnel.\n",
              GNUNET_i2s (peer));
   GNUNET_STATISTICS_update (stats,
-                           gettext_noop ("# Peers connected to mesh tunnels"),
+                           gettext_noop ("# peers connected to mesh tunnels"),
                            -1, GNUNET_NO);
   if (NULL != ts->th)
   {
@@ -620,14 +639,15 @@ tunnel_peer_disconnect_handler (void *cls,
  * Method called whenever a peer has connected to the tunnel.  Notifies
  * the waiting client that the tunnel is now up.
  *
+ * FIXME merge with tunnel_create
+ * 
  * @param cls closure
  * @param peer peer identity the tunnel was created to, NULL on timeout
  * @param atsi performance data for the connection
  */
-static void
+void
 tunnel_peer_connect_handler (void *cls,
-                            const struct GNUNET_PeerIdentity
-                            * peer,
+                            const struct GNUNET_PeerIdentity *peer,
                             const struct
                             GNUNET_ATS_Information * atsi)
 {
@@ -637,7 +657,7 @@ tunnel_peer_connect_handler (void *cls,
              "Peer %s connected to tunnel.\n",
              GNUNET_i2s (peer));
   GNUNET_STATISTICS_update (stats,
-                           gettext_noop ("# Peers connected to mesh tunnels"),
+                           gettext_noop ("# peers connected to mesh tunnels"),
                            1, GNUNET_NO);
   if (NULL == ts->client)
     return; /* nothing to do */
@@ -645,7 +665,6 @@ tunnel_peer_connect_handler (void *cls,
                     ts->request_id,
                     ts->af,
                     &ts->destination_ip);
-  GNUNET_SERVER_client_drop (ts->client);
   ts->client = NULL;
 }
 
@@ -653,10 +672,10 @@ tunnel_peer_connect_handler (void *cls,
 /**
  * Send a message from the message queue via mesh.
  *
- * @param cls the 'struct TunnelState' with the message queue
- * @param size number of bytes available in buf
+ * @param cls the `struct TunnelState` with the message queue
+ * @param size number of bytes available in @a buf
  * @param buf where to copy the message
- * @return number of bytes copied to buf
+ * @return number of bytes copied to @a buf
  */
 static size_t
 send_to_peer_notify_callback (void *cls, size_t size, void *buf)
@@ -684,9 +703,7 @@ send_to_peer_notify_callback (void *cls, size_t size, void *buf)
   if (NULL != (tnq = ts->tmq_head))
     ts->th = GNUNET_MESH_notify_transmit_ready (ts->tunnel, 
                                                GNUNET_NO /* cork */, 
-                                               42 /* priority */,
                                                GNUNET_TIME_UNIT_FOREVER_REL,
-                                               NULL, 
                                                tnq->len,
                                                &send_to_peer_notify_callback,
                                                ts);
@@ -737,20 +754,50 @@ send_to_tunnel (struct TunnelMessageQueueEntry *tnq,
   if (NULL == ts->th)
     ts->th = GNUNET_MESH_notify_transmit_ready (ts->tunnel, 
                                                GNUNET_NO /* cork */,
-                                               42 /* priority */,
                                                GNUNET_TIME_UNIT_FOREVER_REL,
-                                               NULL, 
                                                tnq->len,
                                                &send_to_peer_notify_callback,
                                                ts);
 }
 
 
+/**
+ * Regex has found a potential exit peer for us; consider using it.
+ *
+ * @param cls the 'struct TunnelState'
+ * @param id Peer providing a regex that matches the string.
+ * @param get_path Path of the get request.
+ * @param get_path_length Lenght of get_path.
+ * @param put_path Path of the put request.
+ * @param put_path_length Length of the put_path.
+ */
+static void
+handle_regex_result (void *cls,
+                    const struct GNUNET_PeerIdentity *id,
+                    const struct GNUNET_PeerIdentity *get_path,
+                    unsigned int get_path_length,
+                    const struct GNUNET_PeerIdentity *put_path,
+                    unsigned int put_path_length)
+{
+  struct TunnelState *ts = cls;
+
+  GNUNET_REGEX_search_cancel (ts->search);
+  ts->search = NULL;
+  ts->tunnel = GNUNET_MESH_tunnel_create (mesh_handle,
+                                          ts,
+                                          id,
+                                          PORT_VPN,
+                                          GNUNET_YES,
+                                          GNUNET_NO);
+}
+
+
 /**
  * Initialize the given destination entry's mesh tunnel.
  *
  * @param de destination entry for which we need to setup a tunnel
  * @param client client to notify on successful tunnel setup, or NULL for none
+ * @param client_af address family of the address returned to the client
  * @param request_id request ID to send in client notification (unused if client is NULL)
  * @return tunnel state of the tunnel that was created
  */
@@ -766,64 +813,81 @@ create_tunnel_to_destination (struct DestinationEntry *de,
                            gettext_noop ("# Mesh tunnels created"),
                            1, GNUNET_NO);
   GNUNET_assert (NULL == de->ts);
-  ts = GNUNET_malloc (sizeof (struct TunnelState));
+  ts = GNUNET_new (struct TunnelState);
   ts->af = client_af;
   if (NULL != client)
   {
     ts->request_id = request_id;
     ts->client = client;
-    GNUNET_SERVER_client_keep (client);
   }
   ts->destination = *de;
   ts->destination.heap_node = NULL; /* copy is NOT in destination heap */
   de->ts = ts;
   ts->destination_container = de; /* we are referenced from de */
-  ts->tunnel = GNUNET_MESH_tunnel_create (mesh_handle,
-                                         ts,
-                                         &tunnel_peer_connect_handler,
-                                         &tunnel_peer_disconnect_handler,
-                                         ts);
-  if (NULL == ts->tunnel)
-  {
-    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
-               _("Failed to setup mesh tunnel!\n"));
-    if (NULL != client)
-      GNUNET_SERVER_client_drop (client);
-    GNUNET_free (ts);
-    return NULL;
-  }
   if (de->is_service)
   {
+    ts->tunnel = GNUNET_MESH_tunnel_create (mesh_handle,
+                                           ts,
+                                           &de->details.service_destination.target,
+                                           PORT_VPN,
+                                           GNUNET_YES,
+                                           GNUNET_NO);
+    if (NULL == ts->tunnel)
+    {
+      GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                 _("Failed to setup mesh tunnel!\n"));
+      GNUNET_free (ts);
+      return NULL;
+    }
     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
                "Creating tunnel to peer %s offering service %s\n",
                GNUNET_i2s (&de->details.service_destination.target),
                GNUNET_h2s (&de->details.service_destination.service_descriptor));
-    GNUNET_MESH_peer_request_connect_add (ts->tunnel,
-                                         &de->details.service_destination.target);  
   }
   else
   {
+    char *policy;
+
     switch (de->details.exit_destination.af)
     {
     case AF_INET:
-      GNUNET_MESH_peer_request_connect_by_type (ts->tunnel,
-                                               GNUNET_APPLICATION_TYPE_IPV4_GATEWAY);
-      GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
-                 "Creating tunnel to exit peer for %s\n",
-                 "IPv4");
-     break;
+    {
+      char address[GNUNET_TUN_IPV4_REGEXLEN];
+
+      GNUNET_TUN_ipv4toregexsearch (&de->details.exit_destination.ip.v4,
+                  "255.255.255.255", address);
+      GNUNET_asprintf (&policy, "%s%s%s",
+                       GNUNET_APPLICATION_TYPE_EXIT_REGEX_PREFIX,
+                       "4",
+                       address);
+      break;
+    }
     case AF_INET6:
-      GNUNET_MESH_peer_request_connect_by_type (ts->tunnel,
-                                               GNUNET_APPLICATION_TYPE_IPV6_GATEWAY);
-      GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
-                 "Creating tunnel to exit peer for %s\n",
-                 "IPv6");
+    {
+      char address[GNUNET_TUN_IPV6_REGEXLEN];
+      
+      GNUNET_TUN_ipv6toregexsearch (&de->details.exit_destination.ip.v6,
+                  128, address);
+      GNUNET_asprintf (&policy, "%s%s%s",
+                       GNUNET_APPLICATION_TYPE_EXIT_REGEX_PREFIX,
+                       "6",
+                       address);
       break;
+    }
     default:
       GNUNET_assert (0);
       break;
     }
-  }  
+
+    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+               "Requesting connect by string: %s\n",
+               policy);
+    ts->search = GNUNET_REGEX_search (cfg,
+                                     policy,
+                                     &handle_regex_result,
+                                     ts);
+    GNUNET_free (policy);
+  }
   return ts;
 }
 
@@ -851,7 +915,7 @@ expire_tunnel (struct TunnelState *except)
  *
  * @param destination description of the destination
  * @param af address family on this end (AF_INET or AF_INET6)
- * @param protocol IPPROTO_TCP or IPPROTO_UDP
+ * @param protocol IPPROTO_TCP or IPPROTO_UDP or IPPROTO_ICMP or IPPROTO_ICMPV6
  * @param source_ip source IP used by the sender (struct in_addr or struct in6_addr)
  * @param destination_ip destination IP used by the sender (struct in_addr or struct in6_addr)
  * @param payload payload of the packet after the IP header
@@ -866,7 +930,7 @@ route_packet (struct DestinationEntry *destination,
              const void *payload,
              size_t payload_length)
 {
-  GNUNET_HashCode key;
+  struct GNUNET_HashCode key;
   struct TunnelState *ts;
   struct TunnelMessageQueueEntry *tnq;
   size_t alen;
@@ -875,8 +939,8 @@ route_packet (struct DestinationEntry *destination,
   const struct GNUNET_TUN_UdpHeader *udp;
   const struct GNUNET_TUN_TcpHeader *tcp;
   const struct GNUNET_TUN_IcmpHeader *icmp;
-  uint16_t spt;
-  uint16_t dpt;
+  uint16_t source_port;
+  uint16_t destination_port;
 
   switch (protocol)
   {
@@ -888,15 +952,22 @@ route_packet (struct DestinationEntry *destination,
        GNUNET_break (0);
        return;
       }
+      tcp = NULL; /* make compiler happy */
+      icmp = NULL;  /* make compiler happy */
       udp = payload;
-      spt = ntohs (udp->spt);
-      dpt = ntohs (udp->dpt);
+      if (udp->len < sizeof (struct GNUNET_TUN_UdpHeader))
+      {
+       GNUNET_break_op (0);
+       return;
+      }
+      source_port = ntohs (udp->source_port);
+      destination_port = ntohs (udp->destination_port);
       get_tunnel_key_from_ips (af,
                               IPPROTO_UDP,
                               source_ip,
-                              spt,
+                              source_port,
                               destination_ip,
-                              dpt,
+                              destination_port,
                               &key);
     }
     break;
@@ -907,32 +978,47 @@ route_packet (struct DestinationEntry *destination,
        /* blame kernel? */
        GNUNET_break (0);
        return;
-      }
+      }      
+      udp = NULL; /* make compiler happy */
+      icmp = NULL;  /* make compiler happy */
       tcp = payload;
-      spt = ntohs (tcp->spt);
-      dpt = ntohs (tcp->dpt);
+      if (tcp->off * 4 < sizeof (struct GNUNET_TUN_TcpHeader))
+      {
+       GNUNET_break_op (0);
+       return;
+      }
+      source_port = ntohs (tcp->source_port);
+      destination_port = ntohs (tcp->destination_port);
       get_tunnel_key_from_ips (af,
                               IPPROTO_TCP,
                               source_ip,
-                              spt,
+                              source_port,
                               destination_ip,
-                              dpt,
+                              destination_port,
                               &key);
     }
     break;
-  case IPPROTO_ICMP:
+  case IPPROTO_ICMP:  
+  case IPPROTO_ICMPV6:  
     {
+      if ( (AF_INET == af) ^ (protocol == IPPROTO_ICMP) )
+      {
+       GNUNET_break (0);
+       return;
+      }
       if (payload_length < sizeof (struct GNUNET_TUN_IcmpHeader))
       {
        /* blame kernel? */
        GNUNET_break (0);
        return;
       }
+      tcp = NULL; /* make compiler happy */
+      udp = NULL;  /* make compiler happy */
       icmp = payload;
-      spt = 0;
-      dpt = 0;
+      source_port = 0;
+      destination_port = 0;
       get_tunnel_key_from_ips (af,
-                              IPPROTO_ICMP,
+                              protocol,
                               source_ip,
                               0,
                               destination_ip,
@@ -946,6 +1032,7 @@ route_packet (struct DestinationEntry *destination,
                (unsigned int) protocol);
     return;
   }
+  alen = 0;
   if (! destination->is_service)
   {  
     switch (destination->details.exit_destination.af)
@@ -957,7 +1044,6 @@ route_packet (struct DestinationEntry *destination,
       alen = sizeof (struct in6_addr);
       break;
     default:
-      alen = 0;
       GNUNET_assert (0);
     }
 
@@ -970,19 +1056,17 @@ route_packet (struct DestinationEntry *destination,
                  "Routing %s packet from %s:%u -> %s:%u to destination %s:%u\n",
                  (protocol == IPPROTO_TCP) ? "TCP" : "UDP",
                  inet_ntop (af, source_ip, sbuf, sizeof (sbuf)),
-                 spt,
+                 source_port,
                  inet_ntop (af, destination_ip, dbuf, sizeof (dbuf)),
-                 dpt,
+                 destination_port,
                  inet_ntop (destination->details.exit_destination.af,
                             &destination->details.exit_destination.ip,
                             xbuf, sizeof (xbuf)),
-                 dpt);
+                 destination_port);
     }
   }
   else
   {
-    /* make compiler happy */
-    alen = 0;
     {
       char sbuf[INET6_ADDRSTRLEN];
       char dbuf[INET6_ADDRSTRLEN];
@@ -991,9 +1075,9 @@ route_packet (struct DestinationEntry *destination,
                  "Routing %s packet from %s:%u -> %s:%u to service %s at peer %s\n",
                  (protocol == IPPROTO_TCP) ? "TCP" : "UDP",
                  inet_ntop (af, source_ip, sbuf, sizeof (sbuf)),
-                 spt,
+                 source_port,
                  inet_ntop (af, destination_ip, dbuf, sizeof (dbuf)),
-                 dpt,
+                 destination_port,
                  GNUNET_h2s (&destination->details.service_destination.service_descriptor),
                  GNUNET_i2s (&destination->details.service_destination.target));
     }
@@ -1029,11 +1113,11 @@ route_packet (struct DestinationEntry *destination,
       ts->source_ip.v6 = * (const struct in6_addr *) source_ip;
       ts->destination_ip.v6 = * (const struct in6_addr *) destination_ip;
     }
-    ts->source_port = spt;
-    ts->destination_port = dpt;
+    ts->source_port = source_port;
+    ts->destination_port = destination_port;
     ts->heap_node = GNUNET_CONTAINER_heap_insert (tunnel_heap,
                                                  ts,
-                                                 GNUNET_TIME_absolute_get ().abs_value);
+                                                 GNUNET_TIME_absolute_get ().abs_value_us);
     GNUNET_assert (GNUNET_YES ==
                   GNUNET_CONTAINER_multihashmap_put (tunnel_map,
                                                      &key,
@@ -1050,7 +1134,7 @@ route_packet (struct DestinationEntry *destination,
     is_new = GNUNET_NO;
     GNUNET_CONTAINER_heap_update_cost (tunnel_heap, 
                                       ts->heap_node,
-                                      GNUNET_TIME_absolute_get ().abs_value);
+                                      GNUNET_TIME_absolute_get ().abs_value_us);
   }
   GNUNET_assert (NULL != ts->tunnel);
   
@@ -1077,8 +1161,8 @@ route_packet (struct DestinationEntry *destination,
       usm->header.type = htons (GNUNET_MESSAGE_TYPE_VPN_UDP_TO_SERVICE);
       /* if the source port is below 32000, we assume it has a special
         meaning; if not, we pick a random port (this is a heuristic) */
-      usm->source_port = (ntohs (udp->spt) < 32000) ? udp->spt : 0;
-      usm->destination_port = udp->dpt;
+      usm->source_port = (ntohs (udp->source_port) < 32000) ? udp->source_port : 0;
+      usm->destination_port = udp->destination_port;
       usm->service_descriptor = destination->details.service_destination.service_descriptor;
       memcpy (&usm[1],
              &udp[1],
@@ -1106,8 +1190,8 @@ route_packet (struct DestinationEntry *destination,
       uim->header.size = htons ((uint16_t) mlen);
       uim->header.type = htons (GNUNET_MESSAGE_TYPE_VPN_UDP_TO_INTERNET); 
       uim->af = htonl (destination->details.exit_destination.af);
-      uim->source_port = (ntohs (udp->spt) < 32000) ? udp->spt : 0;
-      uim->destination_port = udp->dpt;
+      uim->source_port = (ntohs (udp->source_port) < 32000) ? udp->source_port : 0;
+      uim->destination_port = udp->destination_port;
       switch (destination->details.exit_destination.af)
       {
       case AF_INET:
@@ -1222,6 +1306,7 @@ route_packet (struct DestinationEntry *destination,
      }
     break;
   case IPPROTO_ICMP:
+  case IPPROTO_ICMPV6:
     if (destination->is_service)
     {
       struct GNUNET_EXIT_IcmpServiceMessage *ism;
@@ -1475,13 +1560,13 @@ route_packet (struct DestinationEntry *destination,
  * @param client NULL
  * @param message message we got from the client (VPN tunnel interface)
  */
-static void
+static int
 message_token (void *cls GNUNET_UNUSED, void *client GNUNET_UNUSED,
                const struct GNUNET_MessageHeader *message)
 {
   const struct GNUNET_TUN_Layer2PacketHeader *tun;
   size_t mlen;
-  GNUNET_HashCode key;
+  struct GNUNET_HashCode key;
   struct DestinationEntry *de;
 
   GNUNET_STATISTICS_update (stats,
@@ -1492,7 +1577,7 @@ message_token (void *cls GNUNET_UNUSED, void *client GNUNET_UNUSED,
        (mlen < sizeof (struct GNUNET_MessageHeader) + sizeof (struct GNUNET_TUN_Layer2PacketHeader)) )
   {
     GNUNET_break (0);
-    return;
+    return GNUNET_OK;
   }
   tun = (const struct GNUNET_TUN_Layer2PacketHeader *) &message[1];
   mlen -= (sizeof (struct GNUNET_MessageHeader) + sizeof (struct GNUNET_TUN_Layer2PacketHeader));
@@ -1506,18 +1591,13 @@ message_token (void *cls GNUNET_UNUSED, void *client GNUNET_UNUSED,
       {
        /* blame kernel */
        GNUNET_break (0);
-       return;
+        return GNUNET_OK;
       }
       pkt6 = (const struct GNUNET_TUN_IPv6Header *) &tun[1];
       get_destination_key_from_ip (AF_INET6,
                                   &pkt6->destination_address,
                                   &key);
       de = GNUNET_CONTAINER_multihashmap_get (destination_map, &key);
-      /* FIXME: do we need to guard against hash collision? 
-        (if so, we need to also store the local destination IP in the
-        destination entry and then compare here; however, the risk
-        of collision seems minimal AND the impact is unlikely to be
-        super-problematic as well... */
       if (NULL == de)
       {
        char buf[INET6_ADDRSTRLEN];
@@ -1528,7 +1608,7 @@ message_token (void *cls GNUNET_UNUSED, void *client GNUNET_UNUSED,
                               &pkt6->destination_address,
                               buf,
                               sizeof (buf)));
-       return;
+       return GNUNET_OK;
       }
       route_packet (de,
                    AF_INET6,
@@ -1547,18 +1627,13 @@ message_token (void *cls GNUNET_UNUSED, void *client GNUNET_UNUSED,
       {
        /* blame kernel */
        GNUNET_break (0);
-       return;
+       return GNUNET_OK;
       }
       pkt4 = (struct GNUNET_TUN_IPv4Header *) &tun[1];
       get_destination_key_from_ip (AF_INET,
                                   &pkt4->destination_address,
                                   &key);
       de = GNUNET_CONTAINER_multihashmap_get (destination_map, &key);
-      /* FIXME: do we need to guard against hash collision? 
-        (if so, we need to also store the local destination IP in the
-        destination entry and then compare here; however, the risk
-        of collision seems minimal AND the impact is unlikely to be
-        super-problematic as well... */
       if (NULL == de)
       {
        char buf[INET_ADDRSTRLEN];
@@ -1569,13 +1644,13 @@ message_token (void *cls GNUNET_UNUSED, void *client GNUNET_UNUSED,
                               &pkt4->destination_address,
                               buf,
                               sizeof (buf)));
-       return;
+        return GNUNET_OK;
       }
       if (pkt4->header_length * 4 != sizeof (struct GNUNET_TUN_IPv4Header))
       {
        GNUNET_log (GNUNET_ERROR_TYPE_INFO,
                    _("Received IPv4 packet with options (dropping it)\n"));                
-       return;
+        return GNUNET_OK;
       }
       route_packet (de,
                    AF_INET,
@@ -1592,6 +1667,7 @@ message_token (void *cls GNUNET_UNUSED, void *client GNUNET_UNUSED,
                (unsigned int) ntohs (tun->proto));
     break;
   }
+  return GNUNET_OK;
 }
 
 
@@ -1614,8 +1690,8 @@ make_up_icmpv4_payload (struct TunnelState *ts,
                                     sizeof (struct GNUNET_TUN_TcpHeader),
                                     &ts->source_ip.v4,
                                     &ts->destination_ip.v4);
-  udp->spt = htons (ts->source_port);
-  udp->dpt = htons (ts->destination_port);
+  udp->source_port = htons (ts->source_port);
+  udp->destination_port = htons (ts->destination_port);
   udp->len = htons (0);
   udp->crc = htons (0);
 }
@@ -1640,8 +1716,8 @@ make_up_icmpv6_payload (struct TunnelState *ts,
                                     sizeof (struct GNUNET_TUN_TcpHeader),
                                     &ts->source_ip.v6,
                                     &ts->destination_ip.v6);
-  udp->spt = htons (ts->source_port);
-  udp->dpt = htons (ts->destination_port);
+  udp->source_port = htons (ts->source_port);
+  udp->destination_port = htons (ts->destination_port);
   udp->len = htons (0);
   udp->crc = htons (0);
 }
@@ -1654,17 +1730,14 @@ make_up_icmpv6_payload (struct TunnelState *ts,
  * @param cls closure, NULL
  * @param tunnel connection to the other end
  * @param tunnel_ctx pointer to our 'struct TunnelState *'
- * @param sender who sent the message
  * @param message the actual message
- * @param atsi performance data for the connection
- * @return GNUNET_OK to keep the connection open,
- *         GNUNET_SYSERR to close it (signal serious error)
+ * @return #GNUNET_OK to keep the connection open,
+ *         #GNUNET_SYSERR to close it (signal serious error)
  */ 
 static int
 receive_icmp_back (void *cls GNUNET_UNUSED, struct GNUNET_MESH_Tunnel *tunnel,
-                  void **tunnel_ctx, const struct GNUNET_PeerIdentity *sender,
-                  const struct GNUNET_MessageHeader *message,
-                  const struct GNUNET_ATS_Information *atsi GNUNET_UNUSED)
+                  void **tunnel_ctx,
+                  const struct GNUNET_MessageHeader *message)
 {
   struct TunnelState *ts = *tunnel_ctx;
   const struct GNUNET_EXIT_IcmpToVPNMessage *i2v;
@@ -1713,7 +1786,7 @@ receive_icmp_back (void *cls GNUNET_UNUSED, struct GNUNET_MESH_Tunnel *tunnel,
       {
        /* reserve some extra space in case we have an ICMP type here where
           we will need to make up the payload ourselves */
-       char buf[size + sizeof (struct GNUNET_TUN_IPv4Header) + 8];
+       char buf[size + sizeof (struct GNUNET_TUN_IPv4Header) + 8] GNUNET_ALIGN;
        struct GNUNET_MessageHeader *msg = (struct GNUNET_MessageHeader *) buf;
        struct GNUNET_TUN_Layer2PacketHeader *tun = (struct GNUNET_TUN_Layer2PacketHeader*) &msg[1];
        struct GNUNET_TUN_IPv4Header *ipv4 = (struct GNUNET_TUN_IPv4Header *) &tun[1];
@@ -1850,7 +1923,7 @@ receive_icmp_back (void *cls GNUNET_UNUSED, struct GNUNET_MESH_Tunnel *tunnel,
        sizeof (struct GNUNET_TUN_Layer2PacketHeader) +
        mlen;
       {
-       char buf[size + sizeof (struct GNUNET_TUN_IPv6Header) + 8];
+       char buf[size + sizeof (struct GNUNET_TUN_IPv6Header) + 8] GNUNET_ALIGN;
        struct GNUNET_MessageHeader *msg = (struct GNUNET_MessageHeader *) buf;
        struct GNUNET_TUN_Layer2PacketHeader *tun = (struct GNUNET_TUN_Layer2PacketHeader*) &msg[1];
        struct GNUNET_TUN_IPv6Header *ipv6 = (struct GNUNET_TUN_IPv6Header *) &tun[1];
@@ -1859,7 +1932,7 @@ receive_icmp_back (void *cls GNUNET_UNUSED, struct GNUNET_MESH_Tunnel *tunnel,
        tun->flags = htons (0);
        tun->proto = htons (ETH_P_IPV6);
        GNUNET_TUN_initialize_ipv6_header (ipv6,
-                                          IPPROTO_ICMP,
+                                          IPPROTO_ICMPV6,
                                           sizeof (struct GNUNET_TUN_IcmpHeader) + mlen,
                                           &ts->destination_ip.v6,
                                           &ts->source_ip.v6);
@@ -1983,7 +2056,7 @@ receive_icmp_back (void *cls GNUNET_UNUSED, struct GNUNET_MESH_Tunnel *tunnel,
   }
   GNUNET_CONTAINER_heap_update_cost (tunnel_heap, 
                                     ts->heap_node,
-                                    GNUNET_TIME_absolute_get ().abs_value);
+                                    GNUNET_TIME_absolute_get ().abs_value_us);
   return GNUNET_OK;
 }
 
@@ -1995,17 +2068,14 @@ receive_icmp_back (void *cls GNUNET_UNUSED, struct GNUNET_MESH_Tunnel *tunnel,
  * @param cls closure, NULL
  * @param tunnel connection to the other end
  * @param tunnel_ctx pointer to our 'struct TunnelState *'
- * @param sender who sent the message
  * @param message the actual message
- * @param atsi performance data for the connection
- * @return GNUNET_OK to keep the connection open,
- *         GNUNET_SYSERR to close it (signal serious error)
+ * @return #GNUNET_OK to keep the connection open,
+ *         #GNUNET_SYSERR to close it (signal serious error)
  */ 
 static int
 receive_udp_back (void *cls GNUNET_UNUSED, struct GNUNET_MESH_Tunnel *tunnel,
-                  void **tunnel_ctx, const struct GNUNET_PeerIdentity *sender,
-                  const struct GNUNET_MessageHeader *message,
-                  const struct GNUNET_ATS_Information *atsi GNUNET_UNUSED)
+                  void **tunnel_ctx,
+                  const struct GNUNET_MessageHeader *message)
 {
   struct TunnelState *ts = *tunnel_ctx;
   const struct GNUNET_EXIT_UdpReplyMessage *reply;
@@ -2054,7 +2124,7 @@ receive_udp_back (void *cls GNUNET_UNUSED, struct GNUNET_MESH_Tunnel *tunnel,
        sizeof (struct GNUNET_TUN_Layer2PacketHeader) +
        mlen;
       {
-       char buf[size];
+       char buf[size] GNUNET_ALIGN;
        struct GNUNET_MessageHeader *msg = (struct GNUNET_MessageHeader *) buf;
        struct GNUNET_TUN_Layer2PacketHeader *tun = (struct GNUNET_TUN_Layer2PacketHeader*) &msg[1];
        struct GNUNET_TUN_IPv4Header *ipv4 = (struct GNUNET_TUN_IPv4Header *) &tun[1];
@@ -2069,13 +2139,13 @@ receive_udp_back (void *cls GNUNET_UNUSED, struct GNUNET_MESH_Tunnel *tunnel,
                                           &ts->destination_ip.v4,
                                           &ts->source_ip.v4);
        if (0 == ntohs (reply->source_port))
-         udp->spt = htons (ts->destination_port);
+         udp->source_port = htons (ts->destination_port);
        else
-         udp->spt = reply->source_port;
+         udp->source_port = reply->source_port;
        if (0 == ntohs (reply->destination_port))
-         udp->dpt = htons (ts->source_port);
+         udp->destination_port = htons (ts->source_port);
        else
-         udp->dpt = reply->destination_port;
+         udp->destination_port = reply->destination_port;
        udp->len = htons (mlen + sizeof (struct GNUNET_TUN_UdpHeader));
        GNUNET_TUN_calculate_udp4_checksum (ipv4,
                                            udp,
@@ -2099,7 +2169,7 @@ receive_udp_back (void *cls GNUNET_UNUSED, struct GNUNET_MESH_Tunnel *tunnel,
        sizeof (struct GNUNET_TUN_Layer2PacketHeader) +
        mlen;
       {
-       char buf[size];
+       char buf[size] GNUNET_ALIGN;
        struct GNUNET_MessageHeader *msg = (struct GNUNET_MessageHeader *) buf;
        struct GNUNET_TUN_Layer2PacketHeader *tun = (struct GNUNET_TUN_Layer2PacketHeader*) &msg[1];
        struct GNUNET_TUN_IPv6Header *ipv6 = (struct GNUNET_TUN_IPv6Header *) &tun[1];
@@ -2114,13 +2184,13 @@ receive_udp_back (void *cls GNUNET_UNUSED, struct GNUNET_MESH_Tunnel *tunnel,
                                           &ts->destination_ip.v6,
                                           &ts->source_ip.v6);
        if (0 == ntohs (reply->source_port))
-         udp->spt = htons (ts->destination_port);
+         udp->source_port = htons (ts->destination_port);
        else
-         udp->spt = reply->source_port;
+         udp->source_port = reply->source_port;
        if (0 == ntohs (reply->destination_port))
-         udp->dpt = htons (ts->source_port);
+         udp->destination_port = htons (ts->source_port);
        else
-         udp->dpt = reply->destination_port;
+         udp->destination_port = reply->destination_port;
        udp->len = htons (mlen + sizeof (struct GNUNET_TUN_UdpHeader));
        GNUNET_TUN_calculate_udp6_checksum (ipv6,
                                            udp,
@@ -2140,7 +2210,7 @@ receive_udp_back (void *cls GNUNET_UNUSED, struct GNUNET_MESH_Tunnel *tunnel,
   }
   GNUNET_CONTAINER_heap_update_cost (tunnel_heap, 
                                     ts->heap_node,
-                                    GNUNET_TIME_absolute_get ().abs_value);
+                                    GNUNET_TIME_absolute_get ().abs_value_us);
   return GNUNET_OK;
 }
 
@@ -2151,19 +2221,15 @@ receive_udp_back (void *cls GNUNET_UNUSED, struct GNUNET_MESH_Tunnel *tunnel,
  *
  * @param cls closure, NULL
  * @param tunnel connection to the other end
- * @param tunnel_ctx pointer to our 'struct TunnelState *'
- * @param sender who sent the message
+ * @param tunnel_ctx pointer to our `struct TunnelState *`
  * @param message the actual message
- * @param atsi performance data for the connection
- * @return GNUNET_OK to keep the connection open,
- *         GNUNET_SYSERR to close it (signal serious error)
+ * @return #GNUNET_OK to keep the connection open,
+ *         #GNUNET_SYSERR to close it (signal serious error)
  */ 
 static int
 receive_tcp_back (void *cls GNUNET_UNUSED, struct GNUNET_MESH_Tunnel *tunnel,
                   void **tunnel_ctx,
-                  const struct GNUNET_PeerIdentity *sender GNUNET_UNUSED,
-                  const struct GNUNET_MessageHeader *message,
-                  const struct GNUNET_ATS_Information *atsi GNUNET_UNUSED)
+                  const struct GNUNET_MessageHeader *message)
 {
   struct TunnelState *ts = *tunnel_ctx;
   const struct GNUNET_EXIT_TcpDataMessage *data;
@@ -2197,6 +2263,11 @@ receive_tcp_back (void *cls GNUNET_UNUSED, struct GNUNET_MESH_Tunnel *tunnel,
                inet_ntop (ts->af, &ts->source_ip, dbuf, sizeof (dbuf)),
                ts->source_port);
   }
+  if (data->tcp_header.off * 4 < sizeof (struct GNUNET_TUN_TcpHeader))
+  {
+    GNUNET_break_op (0);
+    return GNUNET_SYSERR;
+  }
   switch (ts->af)
   {
   case AF_INET:
@@ -2207,7 +2278,7 @@ receive_tcp_back (void *cls GNUNET_UNUSED, struct GNUNET_MESH_Tunnel *tunnel,
        sizeof (struct GNUNET_TUN_Layer2PacketHeader) +
        mlen;
       {
-       char buf[size];
+       char buf[size] GNUNET_ALIGN;
        struct GNUNET_MessageHeader *msg = (struct GNUNET_MessageHeader *) buf;
        struct GNUNET_TUN_Layer2PacketHeader *tun = (struct GNUNET_TUN_Layer2PacketHeader*) &msg[1];
        struct GNUNET_TUN_IPv4Header *ipv4 = (struct GNUNET_TUN_IPv4Header *) &tun[1];
@@ -2222,8 +2293,8 @@ receive_tcp_back (void *cls GNUNET_UNUSED, struct GNUNET_MESH_Tunnel *tunnel,
                                           &ts->destination_ip.v4,
                                           &ts->source_ip.v4);
        *tcp = data->tcp_header;
-       tcp->spt = htons (ts->destination_port);
-       tcp->dpt = htons (ts->source_port);
+       tcp->source_port = htons (ts->destination_port);
+       tcp->destination_port = htons (ts->source_port);
        GNUNET_TUN_calculate_tcp4_checksum (ipv4,
                                            tcp,
                                            &data[1],
@@ -2246,7 +2317,7 @@ receive_tcp_back (void *cls GNUNET_UNUSED, struct GNUNET_MESH_Tunnel *tunnel,
        sizeof (struct GNUNET_TUN_Layer2PacketHeader) +
        mlen;
       {
-       char buf[size];
+       char buf[size] GNUNET_ALIGN;
        struct GNUNET_MessageHeader *msg = (struct GNUNET_MessageHeader *) buf;
        struct GNUNET_TUN_Layer2PacketHeader *tun = (struct GNUNET_TUN_Layer2PacketHeader*) &msg[1];
        struct GNUNET_TUN_IPv6Header *ipv6 = (struct GNUNET_TUN_IPv6Header *) &tun[1];
@@ -2260,12 +2331,16 @@ receive_tcp_back (void *cls GNUNET_UNUSED, struct GNUNET_MESH_Tunnel *tunnel,
                                           sizeof (struct GNUNET_TUN_TcpHeader) + mlen,
                                           &ts->destination_ip.v6,
                                           &ts->source_ip.v6);
-       tcp->spt = htons (ts->destination_port);
-       tcp->dpt = htons (ts->source_port);
+       *tcp = data->tcp_header;
+       tcp->source_port = htons (ts->destination_port);
+       tcp->destination_port = htons (ts->source_port);
        GNUNET_TUN_calculate_tcp6_checksum (ipv6,
                                            tcp,
-                                           &tcp[1],
+                                           &data[1],
                                            mlen);
+       memcpy (&tcp[1],
+               &data[1],
+               mlen);
        (void) GNUNET_HELPER_send (helper_handle,
                                   msg,
                                   GNUNET_YES,
@@ -2276,7 +2351,7 @@ receive_tcp_back (void *cls GNUNET_UNUSED, struct GNUNET_MESH_Tunnel *tunnel,
   }
   GNUNET_CONTAINER_heap_update_cost (tunnel_heap, 
                                     ts->heap_node,
-                                    GNUNET_TIME_absolute_get ().abs_value);
+                                    GNUNET_TIME_absolute_get ().abs_value_us);
   return GNUNET_OK;
 }
 
@@ -2286,8 +2361,8 @@ receive_tcp_back (void *cls GNUNET_UNUSED, struct GNUNET_MESH_Tunnel *tunnel,
  * for a new redirection.
  *
  * @param v4 where to store the address
- * @return GNUNET_OK on success,
- *         GNUNET_SYSERR on error
+ * @return #GNUNET_OK on success,
+ *         #GNUNET_SYSERR on error
  */
 static int
 allocate_v4_address (struct in_addr *v4)
@@ -2297,7 +2372,7 @@ allocate_v4_address (struct in_addr *v4)
   struct in_addr addr;
   struct in_addr mask;
   struct in_addr rnd;
-  GNUNET_HashCode key;
+  struct GNUNET_HashCode key;
   unsigned int tries;
 
   GNUNET_assert (1 == inet_pton (AF_INET, ipv4addr, &addr));
@@ -2337,8 +2412,8 @@ allocate_v4_address (struct in_addr *v4)
  * for a new redirection.
  *
  * @param v6 where to store the address
- * @return GNUNET_OK on success,
- *         GNUNET_SYSERR on error
+ * @return #GNUNET_OK on success,
+ *         #GNUNET_SYSERR on error
  */
 static int
 allocate_v6_address (struct in6_addr *v6)
@@ -2348,7 +2423,7 @@ allocate_v6_address (struct in6_addr *v6)
   struct in6_addr mask;
   struct in6_addr rnd;
   int i;
-  GNUNET_HashCode key;
+  struct GNUNET_HashCode key;
   unsigned int tries;
 
   GNUNET_assert (1 == inet_pton (AF_INET6, ipv6addr, &addr));
@@ -2356,7 +2431,7 @@ allocate_v6_address (struct in6_addr *v6)
   /* Given ABCD::/96, we want a mask of 'ABCD::FFFF:FFFF,
      thus: */
   mask = addr;
-  for (i=127;i>=128-ipv6prefix;i--)
+  for (i=127;i>=ipv6prefix;i--)
     mask.s6_addr[i / 8] |= (1 << (i % 8));
   
   /* Pick random IPv6 address within the subnet, except 'addr' or 'mask' itself */
@@ -2444,6 +2519,65 @@ expire_destination (struct DestinationEntry *except)
 }
 
 
+/**
+ * Allocate an IP address for the response.  
+ *
+ * @param result_af desired address family; set to the actual
+ *        address family; can initially be AF_UNSPEC if there
+ *        is no preference; will be set to AF_UNSPEC if the
+ *        allocation failed
+ * @param addr set to either v4 or v6 depending on which 
+ *         storage location was used; set to NULL if allocation failed
+ * @param v4 storage space for an IPv4 address
+ * @param v6 storage space for an IPv6 address
+ * @return #GNUNET_OK normally, #GNUNET_SYSERR if `* result_af` was
+ *         an unsupported address family (not AF_INET, AF_INET6 or AF_UNSPEC)
+ */
+static int
+allocate_response_ip (int *result_af,
+                     void **addr,
+                     struct in_addr *v4,
+                     struct in6_addr *v6)
+{
+  *addr = NULL;
+  switch (*result_af)
+  {
+  case AF_INET:
+    if (GNUNET_OK !=
+       allocate_v4_address (v4))
+      *result_af = AF_UNSPEC;
+    else
+      *addr = v4;
+    break;
+  case AF_INET6:
+    if (GNUNET_OK !=
+       allocate_v6_address (v6))
+      *result_af = AF_UNSPEC;
+    else
+      *addr = v6;
+    break;
+  case AF_UNSPEC:
+    if (GNUNET_OK ==
+       allocate_v4_address (v4))
+    {
+      *addr = v4;
+      *result_af = AF_INET;
+    }
+    else if (GNUNET_OK ==
+       allocate_v6_address (v6))
+    {
+      *addr = v6;
+      *result_af = AF_INET6;
+    }
+    break;
+  default:
+    GNUNET_break (0);
+    return GNUNET_SYSERR;
+  }
+  return GNUNET_OK;
+}                    
+
+
 /**
  * A client asks us to setup a redirection via some exit
  * node to a particular IP.  Setup the redirection and
@@ -2451,7 +2585,7 @@ expire_destination (struct DestinationEntry *except)
  *
  * @param cls unused
  * @param client requesting client
- * @param message redirection request (a 'struct RedirectToIpRequestMessage')
+ * @param message redirection request (a `struct RedirectToIpRequestMessage`)
  */
 static void
 service_redirect_to_ip (void *cls GNUNET_UNUSED, struct GNUNET_SERVER_Client *client,
@@ -2466,7 +2600,7 @@ service_redirect_to_ip (void *cls GNUNET_UNUSED, struct GNUNET_SERVER_Client *cl
   struct in6_addr v6;
   void *addr;
   struct DestinationEntry *de;
-  GNUNET_HashCode key;
+  struct GNUNET_HashCode key;
   struct TunnelState *ts;
   
   /* validate and parse request */
@@ -2505,40 +2639,11 @@ service_redirect_to_ip (void *cls GNUNET_UNUSED, struct GNUNET_SERVER_Client *cl
   }
 
   /* allocate response IP */
-  addr = NULL;
   result_af = (int) htonl (msg->result_af);
-  switch (result_af)
+  if (GNUNET_OK != allocate_response_ip (&result_af,
+                                        &addr,
+                                        &v4, &v6))
   {
-  case AF_INET:
-    if (GNUNET_OK !=
-       allocate_v4_address (&v4))
-      result_af = AF_UNSPEC;
-    else
-      addr = &v4;
-    break;
-  case AF_INET6:
-    if (GNUNET_OK !=
-       allocate_v6_address (&v6))
-      result_af = AF_UNSPEC;
-    else
-      addr = &v6;
-    break;
-  case AF_UNSPEC:
-    if (GNUNET_OK ==
-       allocate_v4_address (&v4))
-    {
-      addr = &v4;
-      result_af = AF_INET;
-    }
-    else if (GNUNET_OK ==
-       allocate_v6_address (&v6))
-    {
-      addr = &v6;
-      result_af = AF_INET6;
-    }
-    break;
-  default:
-    GNUNET_break (0);
     GNUNET_SERVER_receive_done (client, GNUNET_SYSERR);
     return;      
   }
@@ -2570,7 +2675,7 @@ service_redirect_to_ip (void *cls GNUNET_UNUSED, struct GNUNET_SERVER_Client *cl
   }
   
   /* setup destination record */
-  de = GNUNET_malloc (sizeof (struct DestinationEntry));
+  de = GNUNET_new (struct DestinationEntry);
   de->is_service = GNUNET_NO;
   de->details.exit_destination.af = addr_af;
   memcpy (&de->details.exit_destination.ip,
@@ -2587,7 +2692,7 @@ service_redirect_to_ip (void *cls GNUNET_UNUSED, struct GNUNET_SERVER_Client *cl
                                                    GNUNET_CONTAINER_MULTIHASHMAPOPTION_MULTIPLE));
   de->heap_node = GNUNET_CONTAINER_heap_insert (destination_heap,
                                                de,
-                                               GNUNET_TIME_absolute_ntoh (msg->expiration_time).abs_value);
+                                               GNUNET_TIME_absolute_ntoh (msg->expiration_time).abs_value_us);
   GNUNET_STATISTICS_update (stats,
                            gettext_noop ("# Active destinations"),
                            1, GNUNET_NO);
@@ -2622,7 +2727,7 @@ service_redirect_to_ip (void *cls GNUNET_UNUSED, struct GNUNET_SERVER_Client *cl
  *
  * @param cls unused
  * @param client requesting client
- * @param message redirection request (a 'struct RedirectToPeerRequestMessage')
+ * @param message redirection request (a `struct RedirectToPeerRequestMessage`)
  */
 static void
 service_redirect_to_service (void *cls GNUNET_UNUSED, struct GNUNET_SERVER_Client *client,
@@ -2634,47 +2739,18 @@ service_redirect_to_service (void *cls GNUNET_UNUSED, struct GNUNET_SERVER_Clien
   struct in6_addr v6;
   void *addr;
   struct DestinationEntry *de;
-  GNUNET_HashCode key;
+  struct GNUNET_HashCode key;
   struct TunnelState *ts;
   
   /*  parse request */
   msg = (const struct RedirectToServiceRequestMessage *) message;
 
   /* allocate response IP */
-  addr = NULL;
   result_af = (int) htonl (msg->result_af);
-  switch (result_af)
+  if (GNUNET_OK != allocate_response_ip (&result_af,
+                                        &addr,
+                                        &v4, &v6))
   {
-  case AF_INET:
-    if (GNUNET_OK !=
-       allocate_v4_address (&v4))
-      result_af = AF_UNSPEC;
-    else
-      addr = &v4;
-    break;
-  case AF_INET6:
-    if (GNUNET_OK !=
-       allocate_v6_address (&v6))
-      result_af = AF_UNSPEC;
-    else
-      addr = &v6;
-    break;
-  case AF_UNSPEC:
-    if (GNUNET_OK ==
-       allocate_v4_address (&v4))
-    {
-      addr = &v4;
-      result_af = AF_INET;
-    }
-    else if (GNUNET_OK ==
-       allocate_v6_address (&v6))
-    {
-      addr = &v6;
-      result_af = AF_INET6;
-    }
-    break;
-  default:
-    GNUNET_break (0);
     GNUNET_SERVER_receive_done (client, GNUNET_SYSERR);
     return;      
   }
@@ -2707,7 +2783,7 @@ service_redirect_to_service (void *cls GNUNET_UNUSED, struct GNUNET_SERVER_Clien
   }
   
   /* setup destination record */
-  de = GNUNET_malloc (sizeof (struct DestinationEntry));
+  de = GNUNET_new (struct DestinationEntry);
   de->is_service = GNUNET_YES;
   de->details.service_destination.service_descriptor = msg->service_descriptor;
   de->details.service_destination.target = msg->target;
@@ -2722,7 +2798,7 @@ service_redirect_to_service (void *cls GNUNET_UNUSED, struct GNUNET_SERVER_Clien
                                                    GNUNET_CONTAINER_MULTIHASHMAPOPTION_MULTIPLE));
   de->heap_node = GNUNET_CONTAINER_heap_insert (destination_heap,
                                                de,
-                                               GNUNET_TIME_absolute_ntoh (msg->expiration_time).abs_value);
+                                               GNUNET_TIME_absolute_ntoh (msg->expiration_time).abs_value_us);
   while (GNUNET_CONTAINER_multihashmap_size (destination_map) > max_destination_mappings)
     expire_destination (de);
   ts = create_tunnel_to_destination (de,
@@ -2745,43 +2821,24 @@ service_redirect_to_service (void *cls GNUNET_UNUSED, struct GNUNET_SERVER_Clien
 }
 
 
-
-/**
- * Function called for inbound tunnels.  As we don't offer
- * any mesh services, this function should never be called.
- *
- * @param cls closure
- * @param tunnel new handle to the tunnel
- * @param initiator peer that started the tunnel
- * @param atsi performance information for the tunnel
- * @return initial tunnel context for the tunnel
- *         (can be NULL -- that's not an error)
- */ 
-static void *
-inbound_tunnel_cb (void *cls, struct GNUNET_MESH_Tunnel *tunnel,
-                  const struct GNUNET_PeerIdentity *initiator,
-                  const struct GNUNET_ATS_Information *atsi)
-{
-  /* How can and why should anyone open an inbound tunnel to vpn? */
-  GNUNET_break (0);
-  return NULL;
-}
-
-
 /**
- * Function called whenever an inbound tunnel is destroyed.  Should clean up
+ * Function called whenever a tunnel is destroyed.  Should clean up
  * any associated state.
- *
- * @param cls closure (set from GNUNET_MESH_connect)
+ * 
+ * @param cls closure (set from #GNUNET_MESH_connect)
  * @param tunnel connection to the other end (henceforth invalid)
  * @param tunnel_ctx place where local state associated
- *                   with the tunnel is stored (our 'struct TunnelState')
+ *                   with the tunnel is stored (our `struct TunnelState`)
  */ 
 static void
-tunnel_cleaner (void *cls, const struct GNUNET_MESH_Tunnel *tunnel, void *tunnel_ctx)
+tunnel_cleaner (void *cls, 
+               const struct GNUNET_MESH_Tunnel *tunnel, 
+               void *tunnel_ctx)
 {
-  /* we don't have inbound tunnels, so this function should never be called */
-  GNUNET_break (0);
+  struct TunnelState *ts = tunnel_ctx;
+
+  ts->tunnel = NULL; /* we must not call GNUNET_MESH_tunnel_destroy() anymore */
+  free_tunnel_state (ts);
 }
 
 
@@ -2790,12 +2847,12 @@ tunnel_cleaner (void *cls, const struct GNUNET_MESH_Tunnel *tunnel, void *tunnel
  *
  * @param cls unused
  * @param key unused
- * @param value a 'struct DestinationEntry *'
- * @return GNUNET_OK (continue to iterate)
+ * @param value a `struct DestinationEntry *`
+ * @return #GNUNET_OK (continue to iterate)
  */
 static int
 cleanup_destination (void *cls,
-                    const GNUNET_HashCode *key,
+                    const struct GNUNET_HashCode *key,
                     void *value)
 {
   struct DestinationEntry *de = value;
@@ -2810,12 +2867,12 @@ cleanup_destination (void *cls,
  *
  * @param cls unused
  * @param key unused
- * @param value a 'struct TunnelState *'
- * @return GNUNET_OK (continue to iterate)
+ * @param value a `struct TunnelState *`
+ * @return #GNUNET_OK (continue to iterate)
  */
 static int
 cleanup_tunnel (void *cls,
-               const GNUNET_HashCode *key,
+               const struct GNUNET_HashCode *key,
                void *value)
 {
   struct TunnelState *ts = value;
@@ -2832,7 +2889,7 @@ cleanup_tunnel (void *cls,
  * @param tc unused
  */
 static void
-cleanup (void *cls GNUNET_UNUSED,
+cleanup (void *cls,
          const struct GNUNET_SCHEDULER_TaskContext *tc)
 {
   unsigned int i;
@@ -2871,8 +2928,8 @@ cleanup (void *cls GNUNET_UNUSED,
     mesh_handle = NULL;
   }
   if (NULL != helper_handle)
-    {
-    GNUNET_HELPER_stop (helper_handle);
+  {
+    GNUNET_HELPER_stop (helper_handle, GNUNET_NO);
     helper_handle = NULL;
   }
   if (NULL != nc)
@@ -2880,9 +2937,9 @@ cleanup (void *cls GNUNET_UNUSED,
     GNUNET_SERVER_notification_context_destroy (nc);
     nc = NULL;
   }
-  if (stats != NULL)
+  if (NULL != stats)
   {
-    GNUNET_STATISTICS_destroy (stats, GNUNET_YES);
+    GNUNET_STATISTICS_destroy (stats, GNUNET_NO);
     stats = NULL;
   }
   for (i=0;i<5;i++)
@@ -2895,22 +2952,19 @@ cleanup (void *cls GNUNET_UNUSED,
  *
  * @param cls the client that disconnected
  * @param key unused
- * @param value a 'struct TunnelState *'
- * @return GNUNET_OK (continue to iterate)
+ * @param value a `struct TunnelState *`
+ * @return #GNUNET_OK (continue to iterate)
  */
 static int
 cleanup_tunnel_client (void *cls,
-                      const GNUNET_HashCode *key,
+                      const struct GNUNET_HashCode *key,
                       void *value)
 {
   struct GNUNET_SERVER_Client *client = cls;
   struct TunnelState *ts = value;
 
   if (client == ts->client)
-  {
-    GNUNET_SERVER_client_drop (ts->client);
     ts->client = NULL;
-  }
   return GNUNET_OK;
 }
 
@@ -2920,12 +2974,12 @@ cleanup_tunnel_client (void *cls,
  *
  * @param cls the client that disconnected
  * @param key unused
- * @param value a 'struct DestinationEntry *'
- * @return GNUNET_OK (continue to iterate)
+ * @param value a `struct DestinationEntry *`
+ * @return #GNUNET_OK (continue to iterate)
  */
 static int
 cleanup_destination_client (void *cls,
-                           const GNUNET_HashCode *key,
+                           const struct GNUNET_HashCode *key,
                            void *value)
 {
   struct GNUNET_SERVER_Client *client = cls;
@@ -2935,10 +2989,7 @@ cleanup_destination_client (void *cls,
   if (NULL == (ts = de->ts))
     return GNUNET_OK;
   if (client == ts->client)
-  {
-    GNUNET_SERVER_client_drop (ts->client);
     ts->client = NULL;
-  }
   return GNUNET_OK;
 }
 
@@ -2951,7 +3002,8 @@ cleanup_destination_client (void *cls,
  * @param client handle to the client that disconnected
  */
 static void
-client_disconnect (void *cls, struct GNUNET_SERVER_Client *client)
+client_disconnect (void *cls, 
+                  struct GNUNET_SERVER_Client *client)
 {
   if (NULL != tunnel_map)
     GNUNET_CONTAINER_multihashmap_iterate (tunnel_map,
@@ -2990,9 +3042,6 @@ run (void *cls,
     { &receive_icmp_back, GNUNET_MESSAGE_TYPE_VPN_ICMP_TO_VPN, 0},
     {NULL, 0, 0}
   };
-  static const GNUNET_MESH_ApplicationType types[] = {
-    GNUNET_APPLICATION_TYPE_END
-  };
   char *ifname;
   char *ipv6addr;
   char *ipv6prefix_s;
@@ -3000,97 +3049,131 @@ run (void *cls,
   char *ipv4mask;
   struct in_addr v4;
   struct in6_addr v6;
+  char *binary;
 
+  binary = GNUNET_OS_get_libexec_binary_path ("gnunet-helper-vpn");
+
+  if (GNUNET_YES !=
+      GNUNET_OS_check_helper_binary (binary, GNUNET_YES, "-d gnunet-vpn - - 169.1.3.3.7 255.255.255.0")) //ipv4 only please!
+  {
+    fprintf (stderr,
+            "`%s' is not SUID, refusing to run.\n",
+            "gnunet-helper-vpn");
+    GNUNET_free (binary);
+    global_ret = 1;
+    return;
+  }
+  GNUNET_free (binary);
   cfg = cfg_;
   stats = GNUNET_STATISTICS_create ("vpn", cfg);
   if (GNUNET_OK !=
-      GNUNET_CONFIGURATION_get_value_number (cfg, "vpn", "MAX_MAPPING",
+      GNUNET_CONFIGURATION_get_value_number (cfg, "VPN", "MAX_MAPPING",
                                             &max_destination_mappings))
     max_destination_mappings = 200;
   if (GNUNET_OK !=
-      GNUNET_CONFIGURATION_get_value_number (cfg, "vpn", "MAX_TUNNELS",
+      GNUNET_CONFIGURATION_get_value_number (cfg, "VPN", "MAX_TUNNELS",
                                             &max_tunnel_mappings))
     max_tunnel_mappings = 200;
 
-  destination_map = GNUNET_CONTAINER_multihashmap_create (max_destination_mappings * 2);
+  destination_map = GNUNET_CONTAINER_multihashmap_create (max_destination_mappings * 2, GNUNET_NO);
   destination_heap = GNUNET_CONTAINER_heap_create (GNUNET_CONTAINER_HEAP_ORDER_MIN);
-  tunnel_map = GNUNET_CONTAINER_multihashmap_create (max_tunnel_mappings * 2);
+  tunnel_map = GNUNET_CONTAINER_multihashmap_create (max_tunnel_mappings * 2, GNUNET_NO);
   tunnel_heap = GNUNET_CONTAINER_heap_create (GNUNET_CONTAINER_HEAP_ORDER_MIN);
 
 
   vpn_argv[0] = GNUNET_strdup ("vpn-gnunet");
   if (GNUNET_SYSERR ==
-      GNUNET_CONFIGURATION_get_value_string (cfg, "vpn", "IFNAME", &ifname))
+      GNUNET_CONFIGURATION_get_value_string (cfg, "VPN", "IFNAME", &ifname))
   {
-    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
-                "No entry 'IFNAME' in configuration!\n");
+    GNUNET_log_config_missing (GNUNET_ERROR_TYPE_ERROR, "VPN", "IFNAME");
     GNUNET_SCHEDULER_shutdown ();
     return;
   }
   vpn_argv[1] = ifname;
-  if ( (GNUNET_SYSERR ==
-       GNUNET_CONFIGURATION_get_value_string (cfg, "vpn", "IPV6ADDR",
-                                              &ipv6addr) ||
-       (1 != inet_pton (AF_INET6, ipv6addr, &v6))) )
+  if (GNUNET_OK == GNUNET_NETWORK_test_pf (PF_INET6))
   {
-    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
-                "No valid entry 'IPV6ADDR' in configuration!\n");
-    GNUNET_SCHEDULER_shutdown ();
-    return;
-  }
-  vpn_argv[2] = ipv6addr;
-  if (GNUNET_SYSERR ==
-      GNUNET_CONFIGURATION_get_value_string (cfg, "vpn", "IPV6PREFIX",
-                                             &ipv6prefix_s))
-  {
-    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
-                "No entry 'IPV6PREFIX' in configuration!\n");
-    GNUNET_SCHEDULER_shutdown ();
-    return;
+    if ( (GNUNET_SYSERR ==
+         GNUNET_CONFIGURATION_get_value_string (cfg, "VPN", "IPV6ADDR",
+                                                &ipv6addr) ||
+         (1 != inet_pton (AF_INET6, ipv6addr, &v6))) )
+    {
+      GNUNET_log_config_invalid (GNUNET_ERROR_TYPE_ERROR, "VPN", "IPV6ADDR", 
+                                _("Must specify valid IPv6 address"));
+      GNUNET_SCHEDULER_shutdown ();
+      return;
+    }
+    vpn_argv[2] = ipv6addr;
+    if (GNUNET_SYSERR ==
+       GNUNET_CONFIGURATION_get_value_string (cfg, "VPN", "IPV6PREFIX",
+                                              &ipv6prefix_s))
+    {
+      GNUNET_log_config_missing (GNUNET_ERROR_TYPE_ERROR, "VPN", "IPV6PREFIX");
+      GNUNET_SCHEDULER_shutdown ();
+      return;
+    }
+    vpn_argv[3] = ipv6prefix_s;
+    if ( (GNUNET_OK !=
+         GNUNET_CONFIGURATION_get_value_number (cfg, "VPN",
+                                                "IPV6PREFIX",
+                                                &ipv6prefix)) ||
+        (ipv6prefix >= 127) )
+    {
+      GNUNET_log_config_invalid (GNUNET_ERROR_TYPE_ERROR, "VPN", "IPV4MASK",
+                                _("Must specify valid IPv6 mask"));
+      GNUNET_SCHEDULER_shutdown ();
+      return;
+    }
   }
-  vpn_argv[3] = ipv6prefix_s;
-  if ( (GNUNET_OK !=
-       GNUNET_CONFIGURATION_get_value_number (cfg, "vpn",
-                                              "IPV6PREFIX",
-                                              &ipv6prefix)) ||
-       (ipv6prefix >= 127) )
+  else
   {
-    GNUNET_SCHEDULER_shutdown ();
-    return;
+    GNUNET_log (GNUNET_ERROR_TYPE_INFO,
+               _("IPv6 support disabled as this system does not support IPv6\n"));
+    vpn_argv[2] = GNUNET_strdup ("-");
+    vpn_argv[3] = GNUNET_strdup ("-");
   }
-
-  if ( (GNUNET_SYSERR ==
-       GNUNET_CONFIGURATION_get_value_string (cfg, "vpn", "IPV4ADDR",
-                                              &ipv4addr) ||
-       (1 != inet_pton (AF_INET, ipv4addr, &v4))) )
+  if (GNUNET_OK == GNUNET_NETWORK_test_pf (PF_INET))
   {
-    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
-                "No valid entry for 'IPV4ADDR' in configuration!\n");
-    GNUNET_SCHEDULER_shutdown ();
-    return;
+    if ( (GNUNET_SYSERR ==
+         GNUNET_CONFIGURATION_get_value_string (cfg, "vpn", "IPV4ADDR",
+                                                &ipv4addr) ||
+         (1 != inet_pton (AF_INET, ipv4addr, &v4))) )
+    {
+      GNUNET_log_config_invalid (GNUNET_ERROR_TYPE_ERROR, "VPN", "IPV4ADDR", 
+                                _("Must specify valid IPv4 address"));
+      GNUNET_SCHEDULER_shutdown ();
+      return;
+    }
+    vpn_argv[4] = ipv4addr;
+    if ( (GNUNET_SYSERR ==
+         GNUNET_CONFIGURATION_get_value_string (cfg, "vpn", "IPV4MASK",
+                                                &ipv4mask) ||
+         (1 != inet_pton (AF_INET, ipv4mask, &v4))) )
+    {
+      GNUNET_log_config_invalid (GNUNET_ERROR_TYPE_ERROR, "VPN", "IPV4MASK",
+                                _("Must specify valid IPv4 mask"));
+      GNUNET_SCHEDULER_shutdown ();
+      return;
+    }
+    vpn_argv[5] = ipv4mask;
   }
-  vpn_argv[4] = ipv4addr;
-  if ( (GNUNET_SYSERR ==
-       GNUNET_CONFIGURATION_get_value_string (cfg, "vpn", "IPV4MASK",
-                                              &ipv4mask) ||
-       (1 != inet_pton (AF_INET, ipv4mask, &v4))) )
+  else
   {
-    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
-                "No valid entry 'IPV4MASK' in configuration!\n");
-    GNUNET_SCHEDULER_shutdown ();
-    return;
+    GNUNET_log (GNUNET_ERROR_TYPE_INFO,
+               _("IPv4 support disabled as this system does not support IPv4\n"));
+    vpn_argv[4] = GNUNET_strdup ("-");
+    vpn_argv[5] = GNUNET_strdup ("-");
   }
-  vpn_argv[5] = ipv4mask;
   vpn_argv[6] = NULL;
 
   mesh_handle =
-    GNUNET_MESH_connect (cfg_, 42 /* queue length */, NULL, 
-                        &inbound_tunnel_cb
+    GNUNET_MESH_connect (cfg_, NULL, 
+                        NULL
                         &tunnel_cleaner, 
                         mesh_handlers,
-                        types);
-  helper_handle = GNUNET_HELPER_start ("gnunet-helper-vpn", vpn_argv,
-                                      &message_token, NULL);
+                        NULL);
+  helper_handle = GNUNET_HELPER_start (GNUNET_NO,
+                                      "gnunet-helper-vpn", vpn_argv,
+                                      &message_token, NULL, NULL);
   nc = GNUNET_SERVER_notification_context_create (server, 1);
   GNUNET_SERVER_add_handlers (server, service_handlers);
   GNUNET_SERVER_disconnect_notify (server, &client_disconnect, NULL);
@@ -3111,7 +3194,7 @@ main (int argc, char *const *argv)
   return (GNUNET_OK ==
           GNUNET_SERVICE_run (argc, argv, "vpn", 
                              GNUNET_SERVICE_OPTION_NONE,
-                              &run, NULL)) ? 0 : 1;
+                              &run, NULL)) ? global_ret : 1;
 }
 
 /* end of gnunet-service-vpn.c */