- compatibility code
[oweals/gnunet.git] / src / transport / gnunet-service-transport_validation.c
index 9583fc1a790dadb5c4252d1f70d66d83cc775f13..e61d1337d1c9130d3281b5ea24aa6ec1b6b04cdd 100644 (file)
 #include "platform.h"
 #include "gnunet-service-transport_validation.h"
 #include "gnunet-service-transport_plugins.h"
+#include "gnunet-service-transport_hello.h"
+#include "gnunet-service-transport_blacklist.h"
 #include "gnunet-service-transport.h"
 #include "gnunet_hello_lib.h"
+#include "gnunet_ats_service.h"
 #include "gnunet_peerinfo_service.h"
+#include "gnunet_signatures.h"
 
-
-/**
- * How long until a HELLO verification attempt should time out?
- * Must be rather small, otherwise a partially successful HELLO
- * validation (some addresses working) might not be available
- * before a client's request for a connection fails for good.
- * Besides, if a single request to an address takes a long time,
- * then the peer is unlikely worthwhile anyway.
- */
-#define HELLO_VERIFICATION_TIMEOUT GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_SECONDS, 15)
+#define KEEP_093_COMPATIBILITY GNUNET_YES
 
 /**
  * How long is a PONG signature valid?  We'll recycle a signature until
 #define HELLO_ADDRESS_EXPIRATION GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_HOURS, 12)
 
 /**
- * How long before an existing address expires should we again try to
- * validate it?  Must be (significantly) smaller than
- * HELLO_ADDRESS_EXPIRATION.
+ * How often do we allow PINGing an address that we have not yet
+ * validated?  This also determines how long we track an address that
+ * we cannot validate (because after this time we can destroy the
+ * validation record).
  */
-#define HELLO_REVALIDATION_START_TIME GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_HOURS, 1)
+#define UNVALIDATED_PING_KEEPALIVE GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_MINUTES, 5)
 
 /**
- * How long before we try to check an address again (if it turned out to
- * be invalid the first time)?
+ * How often do we PING an address that we have successfully validated
+ * in the past but are not actively using?  Should be (significantly)
+ * smaller than HELLO_ADDRESS_EXPIRATION.
  */
-#define MAX_REVALIDATION_FREQUENCY GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_HOURS, 1)
+#define VALIDATED_PING_FREQUENCY GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_MINUTES, 15)
+
+/**
+ * How often do we PING an address that we are currently using?
+ */
+#define CONNECTED_PING_FREQUENCY GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_MINUTES, 2)
+
+/**
+ * How much delay is acceptable for sending the PING or PONG?
+ */
+#define ACCEPTABLE_PING_DELAY GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_SECONDS, 1)
 
 /**
  * Size of the validation map hashmap.
 #define VALIDATION_MAP_SIZE 256
 
 /**
- * Priority to use for PINGs and PONGs
- */ 
-#define PING_PRIORITY 1
+ * Priority to use for PINGs
+ */
+#define PING_PRIORITY 2
+
+/**
+ * Priority to use for PONGs
+ */
+#define PONG_PRIORITY 4
+
+
+GNUNET_NETWORK_STRUCT_BEGIN
 
 /**
  * Message used to ask a peer to validate receipt (to check an address
@@ -137,11 +152,8 @@ struct TransportPongMessage
   struct GNUNET_CRYPTO_RsaSignature signature;
 
   /**
-   * What are we signing and why?  Two possible reason codes can be here:
    * GNUNET_SIGNATURE_PURPOSE_TRANSPORT_PONG_OWN to confirm that this is a
-   * plausible address for this peer (pid is set to identity of signer); or
-   * GNUNET_SIGNATURE_PURPOSE_TRANSPORT_PONG_USING to confirm that this is
-   * an address we used to connect to the peer with the given pid.
+   * plausible address for the signing peer.
    */
   struct GNUNET_CRYPTO_RsaSignaturePurpose purpose;
 
@@ -150,41 +162,38 @@ struct TransportPongMessage
    */
   struct GNUNET_TIME_AbsoluteNBO expiration;
 
-  /**
-   * Either the identity of the peer Who signed this message, or the
-   * identity of the peer that we're connected to using the given
-   * address (depending on purpose.type).
-   */
-  struct GNUNET_PeerIdentity pid;
-
   /**
    * Size of address appended to this message (part of what is
    * being signed, hence not redundant).
    */
-  uint32_t addrlen;
+  uint32_t addrlen GNUNET_PACKED;
 
 };
-
+GNUNET_NETWORK_STRUCT_END
 
 /**
  * Information about an address under validation
  */
-struct ValidationEntry 
+struct ValidationEntry
 {
 
   /**
-   * Name of the transport.
+   * The address.
    */
-  char *transport_name;
+  struct GNUNET_HELLO_Address *address;
 
   /**
-   * The address, actually a pointer to the end
-   * of this struct.  Do not free!
+   * Handle to the blacklist check (if we're currently in it).
    */
-  const void *addr;
+  struct GST_BlacklistCheck *bc;
 
   /**
-   * The identity of the peer.
+   * Public key of the peer.
+   */
+  struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded public_key;
+
+  /**
+   * The identity of the peer. FIXME: duplicated (also in 'address')
    */
   struct GNUNET_PeerIdentity pid;
 
@@ -194,7 +203,12 @@ struct ValidationEntry
   GNUNET_SCHEDULER_TaskIdentifier timeout_task;
 
   /**
-   * At what time did we send the latest validation request?
+   * ID of task that will trigger address revalidation.
+   */
+  GNUNET_SCHEDULER_TaskIdentifier revalidation_task;
+
+  /**
+   * At what time did we send the latest validation request (PING)?
    */
   struct GNUNET_TIME_Absolute send_time;
 
@@ -210,18 +224,38 @@ struct ValidationEntry
    * ZERO if the address is considered valid (no validation needed)
    * otherwise a time in the future if we're currently denying re-validation
    */
-  struct GNUNET_TIME_Absolute validation_block;
-                                           
+  struct GNUNET_TIME_Absolute revalidation_block;
+
+  /**
+   * Last observed latency for this address (round-trip), delay between
+   * last PING sent and PONG received; FOREVER if we never got a PONG.
+   */
+  struct GNUNET_TIME_Relative latency;
+
   /**
    * Challenge number we used.
    */
   uint32_t challenge;
 
   /**
-   * Length of addr.
+   * When passing the address in 'add_valid_peer_address', did we
+   * copy the address to the HELLO yet?
    */
-  size_t addrlen;
+  int copied;
 
+  /**
+   * Are we currently using this address for a connection?
+   */
+  int in_use;
+
+  /**
+   * Are we expecting a PONG message for this validation entry?
+   */
+  int expecting_pong;
+
+  /* FIXME: DEBUGGING */
+  int last_line_set_to_no;
+  int last_line_set_to_yes;
 };
 
 
@@ -247,11 +281,6 @@ struct CheckHelloValidatedContext
    */
   const struct GNUNET_HELLO_Message *hello;
 
-  /**
-   * Context for peerinfo iteration.
-   */
-  struct GNUNET_PEERINFO_IteratorContext *piter;
-
 };
 
 
@@ -273,19 +302,50 @@ static struct CheckHelloValidatedContext *chvc_tail;
 static struct GNUNET_CONTAINER_MultiHashMap *validation_map;
 
 /**
- * Map of PeerIdentities to 'struct GST_ValidationIteratorContext's.
+ * Context for peerinfo iteration.
  */
-static struct GNUNET_CONTAINER_MultiHashMap *notify_map;
+static struct GNUNET_PEERINFO_NotifyContext *pnc;
 
 
 /**
- * Start the validation subsystem.
+ * Context for the validation entry match function.
  */
-void 
-GST_validation_start ()
+struct ValidationEntryMatchContext
 {
-  validation_map = GNUNET_CONTAINER_multihashmap_create (VALIDATION_MAP_SIZE);
-  notify_map = GNUNET_CONTAINER_multihashmap_create (VALIDATION_MAP_SIZE);
+  /**
+   * Where to store the result?
+   */
+  struct ValidationEntry *ve;
+
+  /**
+   * Address we're interested in.
+   */
+  const struct GNUNET_HELLO_Address *address;
+
+};
+
+
+/**
+ * Iterate over validation entries until a matching one is found.
+ *
+ * @param cls the 'struct ValidationEntryMatchContext'
+ * @param key peer identity (unused)
+ * @param value a 'struct ValidationEntry' to match
+ * @return GNUNET_YES if the entry does not match,
+ *         GNUNET_NO if the entry does match
+ */
+static int
+validation_entry_match (void *cls, const struct GNUNET_HashCode * key, void *value)
+{
+  struct ValidationEntryMatchContext *vemc = cls;
+  struct ValidationEntry *ve = value;
+
+  if (0 == GNUNET_HELLO_address_cmp (ve->address, vemc->address))
+  {
+    vemc->ve = ve;
+    return GNUNET_NO;
+  }
+  return GNUNET_YES;
 }
 
 
@@ -298,130 +358,223 @@ GST_validation_start ()
  * @return GNUNET_YES (continue to iterate)
  */
 static int
-cleanup_validation_entry (void *cls,
-                         const GNUNET_HashCode *key,
-                         void *value)
+cleanup_validation_entry (void *cls, const struct GNUNET_HashCode * key, void *value)
 {
   struct ValidationEntry *ve = value;
-    
-  GNUNET_free (ve->transport_name);
+
+  if (NULL != ve->bc)
+  {
+    GST_blacklist_test_cancel (ve->bc);
+    ve->bc = NULL;
+  }
+  GNUNET_break (GNUNET_OK ==
+                GNUNET_CONTAINER_multihashmap_remove (validation_map,
+                                                      &ve->pid.hashPubKey, ve));
+  GNUNET_HELLO_address_free (ve->address);
   if (GNUNET_SCHEDULER_NO_TASK != ve->timeout_task)
-    {
-      GNUNET_SCHEDULER_cancel (ve->timeout_task);
-      ve->timeout_task = GNUNET_SCHEDULER_NO_TASK;
-    }
+  {
+    GNUNET_SCHEDULER_cancel (ve->timeout_task);
+    ve->timeout_task = GNUNET_SCHEDULER_NO_TASK;
+  }
+  if (GNUNET_SCHEDULER_NO_TASK != ve->revalidation_task)
+  {
+    GNUNET_SCHEDULER_cancel (ve->revalidation_task);
+    ve->revalidation_task = GNUNET_SCHEDULER_NO_TASK;
+  }
   GNUNET_free (ve);
   return GNUNET_OK;
 }
 
 
 /**
- * Stop the validation subsystem.
- */
-void
-GST_validation_stop ()
-{
-  struct CheckHelloValidatedContext *chvc;
-
-  GNUNET_CONTAINER_multihashmap_iterate (validation_map,
-                                        &cleanup_validation_entry,
-                                        NULL);
-  GNUNET_CONTAINER_multihashmap_destroy (validation_map);
-  validation_map = NULL;
-  GNUNET_assert (GNUNET_CONTAINER_multihashmap_size (notify_map) == 0);
-  GNUNET_CONTAINER_multihashmap_destroy (notify_map);
-  notify_map = NULL;
-  while (NULL != (chvc = chvc_head))
-    {
-      GNUNET_CONTAINER_DLL_remove (chvc_head,
-                                  chvc_tail,
-                                  chvc);
-      GNUNET_PEERINFO_iterate_cancel (chvc->piter);      
-      GNUNET_free (chvc);
-    }
-}
-
-
-#if 0
-/**
- * Address validation cleanup task (record no longer needed).
+ * Address validation cleanup task.  Assesses if the record is no
+ * longer valid and then possibly triggers its removal.
  *
  * @param cls the 'struct ValidationEntry'
  * @param tc scheduler context (unused)
  */
 static void
-timeout_hello_validation (void *cls, 
-                         const struct GNUNET_SCHEDULER_TaskContext *tc)
+timeout_hello_validation (void *cls,
+                          const struct GNUNET_SCHEDULER_TaskContext *tc)
 {
-  struct ValidationEntry *va = cls;
-
-  va->timeout_task = GNUNET_SCHEDULER_NO_TASK;
+  struct ValidationEntry *ve = cls;
+  struct GNUNET_TIME_Absolute max;
+  struct GNUNET_TIME_Relative left;
+
+  ve->timeout_task = GNUNET_SCHEDULER_NO_TASK;
+  max = GNUNET_TIME_absolute_max (ve->valid_until, ve->revalidation_block);
+  left = GNUNET_TIME_absolute_get_remaining (max);
+  if (left.rel_value > 0)
+  {
+    /* should wait a bit longer */
+    ve->timeout_task =
+        GNUNET_SCHEDULER_add_delayed (left, &timeout_hello_validation, ve);
+    return;
+  }
   GNUNET_STATISTICS_update (GST_stats,
-                           gettext_noop ("# address records discarded"),
-                           1,
-                           GNUNET_NO);
-  GNUNET_break (GNUNET_OK ==
-                GNUNET_CONTAINER_multihashmap_remove (validation_map,
-                                                     &va->pid.hashPubKey,
-                                                     va));
-  GNUNET_free (va->transport_name);
-  GNUNET_free (va);
+                            gettext_noop ("# address records discarded"), 1,
+                            GNUNET_NO);
+  cleanup_validation_entry (NULL, &ve->pid.hashPubKey, ve);
 }
-#endif
 
 
 /**
- * Context for the validation entry match function.
+ * Function called with the result from blacklisting.
+ * Send a PING to the other peer if a communication is allowed.
+ *
+ * @param cls our 'struct ValidationEntry'
+ * @param pid identity of the other peer
+ * @param result GNUNET_OK if the connection is allowed, GNUNET_NO if not
  */
-struct ValidationEntryMatchContext
+static void
+transmit_ping_if_allowed (void *cls, const struct GNUNET_PeerIdentity *pid,
+                          int result)
 {
-  /**
-   * Where to store the result?
-   */
-  struct ValidationEntry *ve;
-  
-  /**
-   * Transport name we're looking for.
-   */
-  const char *transport_name;
+  struct ValidationEntry *ve = cls;
+  struct TransportPingMessage ping;
+  struct GNUNET_TRANSPORT_PluginFunctions *papi;
+  const struct GNUNET_MessageHeader *hello;
+  ssize_t ret;
+  size_t tsize;
+  size_t slen;
+  uint16_t hsize;
+
+  ve->bc = NULL;
+  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Transmitting plain PING to `%s' %s %s\n",
+              GNUNET_i2s (pid), GST_plugins_a2s (ve->address), ve->address->transport_name);
+
+  slen = strlen (ve->address->transport_name) + 1;
+  hello = GST_hello_get ();
+  hsize = ntohs (hello->size);
+  tsize =
+      sizeof (struct TransportPingMessage) + ve->address->address_length +
+      slen + hsize;
+
+  ping.header.size =
+      htons (sizeof (struct TransportPingMessage) +
+             ve->address->address_length + slen);
+  ping.header.type = htons (GNUNET_MESSAGE_TYPE_TRANSPORT_PING);
+  ping.challenge = htonl (ve->challenge);
+  ping.target = *pid;
 
-  /**
-   * Address we're interested in.
-   */
-  const char *addr;
+  if (tsize >= GNUNET_SERVER_MAX_MESSAGE_SIZE)
+  {
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                _
+                ("Not transmitting `%s' with `%s', message too big (%u bytes!). This should not happen.\n"),
+                "HELLO", "PING", (unsigned int) tsize);
+    /* message too big (!?), get rid of HELLO */
+    hsize = 0;
+    tsize =
+        sizeof (struct TransportPingMessage) + ve->address->address_length +
+        slen + hsize;
+  }
+  {
+    char message_buf[tsize];
 
-  /**
-   * Number of bytes in 'addr'.
-   */
-  size_t addrlen;
-};
+    /* build message with structure:
+     *  [HELLO][TransportPingMessage][Transport name][Address] */
+    memcpy (message_buf, hello, hsize);
+    memcpy (&message_buf[hsize], &ping, sizeof (struct TransportPingMessage));
+    memcpy (&message_buf[sizeof (struct TransportPingMessage) + hsize],
+            ve->address->transport_name, slen);
+    memcpy (&message_buf[sizeof (struct TransportPingMessage) + slen + hsize],
+            ve->address->address, ve->address->address_length);
+    papi = GST_plugins_find (ve->address->transport_name);
+    if (papi == NULL)
+      ret = -1;
+    else
+    {
+      GNUNET_assert (papi->send != NULL);
+      GNUNET_assert (papi->get_session != NULL);
+      struct Session * session = papi->get_session(papi->cls, ve->address);
+
+      if (session != NULL)
+      {
+        ret = papi->send (papi->cls, session,
+                          message_buf, tsize,
+                          PING_PRIORITY, ACCEPTABLE_PING_DELAY,
+                          NULL, NULL);
+      }
+      else
+      {
+        /* Could not get a valid session */
+        GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Could not get a valid session for `%s' %s\n",
+                    GNUNET_i2s (pid), GST_plugins_a2s (ve->address));
+        ret = -1;
+      }
+    }
+  }
+  if (-1 != ret)
+  {
+    ve->send_time = GNUNET_TIME_absolute_get ();
+    GNUNET_STATISTICS_update (GST_stats,
+                              gettext_noop
+                              ("# PING without HELLO messages sent"), 1,
+                              GNUNET_NO);
+    ve->expecting_pong = GNUNET_YES;
+  }
+}
 
 
 /**
- * Iterate over validation entries until a matching one is found.
+ * Do address validation again to keep address valid.
  *
- * @param cls the 'struct ValidationEntryMatchContext'
- * @param key peer identity (unused)
- * @param value a 'struct ValidationEntry' to match
- * @return GNUNET_YES if the entry does not match,
- *         GNUNET_NO if the entry does match
+ * @param cls the 'struct ValidationEntry'
+ * @param tc scheduler context (unused)
  */
-static int
-validation_entry_match (void *cls,
-                       const GNUNET_HashCode *key,
-                       void *value)
+static void
+revalidate_address (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
 {
-  struct ValidationEntryMatchContext *vemc = cls;
-  struct ValidationEntry *ve = value;
-
-  if ( (ve->addrlen == vemc->addrlen) &&
-       (0 == memcmp (ve->addr, vemc->addr, ve->addrlen)) &&
-       (0 == strcmp (ve->transport_name, vemc->transport_name)) )
-    {
-      vemc->ve = ve;
-      return GNUNET_NO;
-    }
-  return GNUNET_YES;
+  struct ValidationEntry *ve = cls;
+  struct GNUNET_TIME_Relative canonical_delay;
+  struct GNUNET_TIME_Relative delay;
+  struct GST_BlacklistCheck *bc;
+  uint32_t rdelay;
+
+  ve->revalidation_task = GNUNET_SCHEDULER_NO_TASK;
+  delay = GNUNET_TIME_absolute_get_remaining (ve->revalidation_block);
+  /* How long until we can possibly permit the next PING? */
+  canonical_delay =
+      (ve->in_use ==
+       GNUNET_YES) ? CONNECTED_PING_FREQUENCY
+      : ((GNUNET_TIME_absolute_get_remaining (ve->valid_until).rel_value >
+          0) ? VALIDATED_PING_FREQUENCY : UNVALIDATED_PING_KEEPALIVE);
+  if (delay.rel_value > canonical_delay.rel_value * 2)
+  {
+    /* situation changed, recalculate delay */
+    delay = canonical_delay;
+    ve->revalidation_block = GNUNET_TIME_relative_to_absolute (delay);
+  }
+  if (delay.rel_value > 0)
+  {
+    /* should wait a bit longer */
+    ve->revalidation_task =
+        GNUNET_SCHEDULER_add_delayed (delay, &revalidate_address, ve);
+    return;
+  }
+  ve->revalidation_block = GNUNET_TIME_relative_to_absolute (canonical_delay);
+
+  /* schedule next PINGing with some extra random delay to avoid synchronous re-validations */
+  rdelay =
+      GNUNET_CRYPTO_random_u32 (GNUNET_CRYPTO_QUALITY_WEAK,
+                                canonical_delay.rel_value);
+  delay =
+      GNUNET_TIME_relative_add (canonical_delay,
+                                GNUNET_TIME_relative_multiply
+                                (GNUNET_TIME_UNIT_MILLISECONDS, rdelay));
+  ve->revalidation_task =
+      GNUNET_SCHEDULER_add_delayed (delay, &revalidate_address, ve);
+
+  /* start PINGing by checking blacklist */
+  GNUNET_STATISTICS_update (GST_stats,
+                            gettext_noop ("# address revalidations started"), 1,
+                            GNUNET_NO);
+  bc = GST_blacklist_test_allowed (&ve->pid, ve->address->transport_name,
+                                   &transmit_ping_if_allowed, ve);
+  if (NULL != bc)
+    ve->bc = bc;                /* only set 'bc' if 'transmit_ping_if_allowed' was not already
+                                 * called... */
 }
 
 
@@ -430,170 +583,592 @@ validation_entry_match (void *cls,
  * the given address and transport.  If none exists, create one (but
  * without starting any validation).
  *
- * @param neighbour which peer we care about
- * @param tname name of the transport plugin
- * @param session session to look for, NULL for 'any'; otherwise
- *        can be used for the service to "learn" this session ID
- *        if 'addr' matches
- * @param addr binary address
- * @param addrlen length of addr
- * @return validation entry matching the given specifications
+ * @param public_key public key of the peer, NULL for unknown
+ * @param address address to find
+ * @return validation entry matching the given specifications, NULL
+ *         if we don't have an existing entry and no public key was given
  */
 static struct ValidationEntry *
-find_validation_entry (struct GNUNET_PeerIdentity *neighbour,
-                      const char *tname,
-                      const char *addr,
-                      size_t addrlen)
+find_validation_entry (const struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded
+                       *public_key, const struct GNUNET_HELLO_Address *address)
 {
   struct ValidationEntryMatchContext vemc;
   struct ValidationEntry *ve;
 
   vemc.ve = NULL;
-  vemc.transport_name = tname;
-  vemc.addr = addr;
-  vemc.addrlen = addrlen;
+  vemc.address = address;
   GNUNET_CONTAINER_multihashmap_get_multiple (validation_map,
-                                             &neighbour->hashPubKey,
-                                             &validation_entry_match,
-                                             &vemc);
+                                              &address->peer.hashPubKey,
+                                              &validation_entry_match, &vemc);
   if (NULL != (ve = vemc.ve))
     return ve;
-  ve = GNUNET_malloc (sizeof (struct ValidationEntry) + addrlen);
-  ve->transport_name = GNUNET_strdup (tname);
-  ve->addr = (void*) &ve[1];
-  ve->pid = *neighbour;
-  ve->challenge = GNUNET_CRYPTO_random_u32 (GNUNET_CRYPTO_QUALITY_NONCE,
-                                           UINT32_MAX);                                            
-  memcpy (&ve[1], addr, addrlen);
-  ve->addrlen = addrlen;
-  GNUNET_CONTAINER_multihashmap_put (validation_map,
-                                    &neighbour->hashPubKey,
-                                    ve,
-                                    GNUNET_CONTAINER_MULTIHASHMAPOPTION_MULTIPLE);
+  if (public_key == NULL)
+    return NULL;
+  ve = GNUNET_malloc (sizeof (struct ValidationEntry));
+  ve->in_use = GNUNET_SYSERR; /* not defined */
+  ve->last_line_set_to_no  = 0;
+  ve->last_line_set_to_yes  = 0;
+  ve->address = GNUNET_HELLO_address_copy (address);
+  ve->public_key = *public_key;
+  ve->pid = address->peer;
+  ve->latency = GNUNET_TIME_UNIT_FOREVER_REL;
+  ve->challenge =
+      GNUNET_CRYPTO_random_u32 (GNUNET_CRYPTO_QUALITY_NONCE, UINT32_MAX);
+  ve->timeout_task =
+      GNUNET_SCHEDULER_add_delayed (UNVALIDATED_PING_KEEPALIVE,
+                                    &timeout_hello_validation, ve);
+  GNUNET_CONTAINER_multihashmap_put (validation_map, &address->peer.hashPubKey,
+                                     ve,
+                                     GNUNET_CONTAINER_MULTIHASHMAPOPTION_MULTIPLE);
+  ve->expecting_pong = GNUNET_NO;
   return ve;
 }
 
 
+/**
+ * Iterator which adds the given address to the set of validated
+ * addresses.
+ *
+ * @param cls original HELLO message
+ * @param address the address
+ * @param expiration expiration time
+ * @return GNUNET_OK (keep the address)
+ */
+static int
+add_valid_address (void *cls, const struct GNUNET_HELLO_Address *address,
+                   struct GNUNET_TIME_Absolute expiration)
+{
+  const struct GNUNET_HELLO_Message *hello = cls;
+  struct ValidationEntry *ve;
+  struct GNUNET_PeerIdentity pid;
+  struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded public_key;
+
+  if (GNUNET_TIME_absolute_get_remaining (expiration).rel_value == 0)
+    return GNUNET_OK;           /* expired */
+  if ((GNUNET_OK != GNUNET_HELLO_get_id (hello, &pid)) ||
+      (GNUNET_OK != GNUNET_HELLO_get_key (hello, &public_key)))
+  {
+    GNUNET_break (0);
+    return GNUNET_OK;           /* invalid HELLO !? */
+  }
+  if (0 == memcmp (&GST_my_identity, &pid, sizeof (struct GNUNET_PeerIdentity)))
+  {
+    /* Peerinfo returned own identity, skip validation */
+    return GNUNET_OK;
+  }
+
+  ve = find_validation_entry (&public_key, address);
+  ve->valid_until = GNUNET_TIME_absolute_max (ve->valid_until, expiration);
+
+  if (GNUNET_SCHEDULER_NO_TASK == ve->revalidation_task)
+    ve->revalidation_task = GNUNET_SCHEDULER_add_now (&revalidate_address, ve);
+  GNUNET_ATS_address_add (GST_ats, address, NULL, NULL, 0);
+  return GNUNET_OK;
+}
+
+
+/**
+ * Function called for any HELLO known to PEERINFO.
+ *
+ * @param cls unused
+ * @param peer id of the peer, NULL for last call
+ * @param hello hello message for the peer (can be NULL)
+ * @param err_msg error message
+ */
+static void
+process_peerinfo_hello (void *cls, const struct GNUNET_PeerIdentity *peer,
+                        const struct GNUNET_HELLO_Message *hello,
+                        const char *err_msg)
+{
+  GNUNET_assert (NULL != peer);
+  if (NULL == hello)
+    return;
+  GNUNET_assert (NULL ==
+                 GNUNET_HELLO_iterate_addresses (hello, GNUNET_NO,
+                                                 &add_valid_address,
+                                                 (void *) hello));
+}
+
+
+/**
+ * Start the validation subsystem.
+ */
+void
+GST_validation_start ()
+{
+  validation_map = GNUNET_CONTAINER_multihashmap_create (VALIDATION_MAP_SIZE);
+  pnc = GNUNET_PEERINFO_notify (GST_cfg, &process_peerinfo_hello, NULL);
+}
+
+
+/**
+ * Stop the validation subsystem.
+ */
+void
+GST_validation_stop ()
+{
+  struct CheckHelloValidatedContext *chvc;
+
+  GNUNET_CONTAINER_multihashmap_iterate (validation_map,
+                                         &cleanup_validation_entry, NULL);
+  GNUNET_CONTAINER_multihashmap_destroy (validation_map);
+  validation_map = NULL;
+  while (NULL != (chvc = chvc_head))
+  {
+    GNUNET_CONTAINER_DLL_remove (chvc_head, chvc_tail, chvc);
+    GNUNET_free (chvc);
+  }
+  GNUNET_PEERINFO_notify_cancel (pnc);
+}
+
+
+/**
+ * Send the given PONG to the given address.
+ *
+ * @param cls the PONG message
+ * @param public_key public key for the peer, never NULL
+ * @param valid_until is ZERO if we never validated the address,
+ *                    otherwise a time up to when we consider it (or was) valid
+ * @param validation_block  is FOREVER if the address is for an unsupported plugin (from PEERINFO)
+ *                          is ZERO if the address is considered valid (no validation needed)
+ *                          otherwise a time in the future if we're currently denying re-validation
+ * @param address target address
+ */
+static void
+multicast_pong (void *cls,
+                const struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded
+                *public_key, struct GNUNET_TIME_Absolute valid_until,
+                struct GNUNET_TIME_Absolute validation_block,
+                const struct GNUNET_HELLO_Address *address)
+{
+  struct TransportPongMessage *pong = cls;
+  struct GNUNET_TRANSPORT_PluginFunctions *papi;
+
+  papi = GST_plugins_find (address->transport_name);
+  if (papi == NULL)
+    return;
+
+  GNUNET_assert (papi->send != NULL);
+  GNUNET_assert (papi->get_session != NULL);
+
+  struct Session * session = papi->get_session(papi->cls, address);
+  if (session == NULL)
+  {
+     GNUNET_break (0);
+     return;
+  }
+
+  papi->send (papi->cls, session,
+              (const char *) pong, ntohs (pong->header.size),
+              PONG_PRIORITY, ACCEPTABLE_PING_DELAY,
+              NULL, NULL);
+}
+
+
 /**
  * We've received a PING.  If appropriate, generate a PONG.
  *
  * @param sender peer sending the PING
  * @param hdr the PING
- * @param plugin_name name of plugin that received the PING
- * @param sender_address address of the sender as known to the plugin, NULL
- *                       if we did not initiate the connection
- * @param sender_address_len number of bytes in sender_address
+ * @param sender_address the sender address as we got it
+ * @param session session we got the PING from
  */
 void
 GST_validation_handle_ping (const struct GNUNET_PeerIdentity *sender,
-                           const struct GNUNET_MessageHeader *hdr,
-                           const char *plugin_name,
-                           const void *sender_address,
-                           size_t sender_address_len)
+                            const struct GNUNET_MessageHeader *hdr,
+                            const struct GNUNET_HELLO_Address *sender_address,
+                            struct Session *session)
 {
+  const struct TransportPingMessage *ping;
+  struct TransportPongMessage *pong;
+  struct GNUNET_TRANSPORT_PluginFunctions *papi;
+  struct GNUNET_CRYPTO_RsaSignature *sig_cache;
+  struct GNUNET_TIME_Absolute *sig_cache_exp;
+  const char *addr;
+  const char *addrend;
+  size_t alen;
+  size_t slen;
+  ssize_t ret;
+  int buggy = GNUNET_NO;
+  struct GNUNET_HELLO_Address address;
+
+  if (ntohs (hdr->size) < sizeof (struct TransportPingMessage))
+  {
+    GNUNET_break_op (0);
+    return;
+  }
+  ping = (const struct TransportPingMessage *) hdr;
+  if (0 !=
+      memcmp (&ping->target, &GST_my_identity,
+              sizeof (struct GNUNET_PeerIdentity)))
+  {
+    GNUNET_STATISTICS_update (GST_stats,
+                              gettext_noop
+                              ("# PING message for different peer received"), 1,
+                              GNUNET_NO);
+    return;
+  }
+  GNUNET_STATISTICS_update (GST_stats,
+                            gettext_noop ("# PING messages received"), 1,
+                            GNUNET_NO);
+  addr = (const char *) &ping[1];
+  alen = ntohs (hdr->size) - sizeof (struct TransportPingMessage);
+  /* peer wants to confirm that this is one of our addresses, this is what is
+   * used for address validation */
+
+  sig_cache = NULL;
+  sig_cache_exp = NULL;
+
+  if (0 < alen)
+  {
+    addrend = memchr (addr, '\0', alen);
+    if (NULL == addrend)
+    {
+      GNUNET_break_op (0);
+      return;
+    }
+    addrend++;
+    slen = strlen (addr) + 1;
+    alen -= slen;
+    address.address = addrend;
+    address.address_length = alen;
+    address.transport_name = addr;
+    address.peer = GST_my_identity;
+
+
+    if (GNUNET_YES != GST_hello_test_address (&address, &sig_cache, &sig_cache_exp))
+    {
+#if KEEP_093_COMPATIBILITY
+      int idsize = sizeof (GST_my_identity);
+      if (alen <= idsize)
+      {
+        if (0 == memcmp (address.address, &GST_my_identity, alen))
+          buggy = GNUNET_YES;
+      }
+      else if (alen <= (idsize + strlen (address.transport_name)))
+      {
+        char *achar = (char *) &address.address;
+        if ((0 == memcmp (address.address, &GST_my_identity, idsize)) &&
+            (0 == memcmp (&achar[idsize], address.transport_name, alen - idsize)))
+          buggy = GNUNET_YES;
+      }
+      else
+      {
+        /* Not predicatable */
+        return;
+      }
+#endif
+      if (GNUNET_NO == buggy)
+      {
+        GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+                    "Not confirming PING from peer `%s' with address `%s' since I cannot confirm having this address.\n",
+                    GNUNET_i2s (sender),
+                    GST_plugins_a2s (&address));
+        return;
+      }
+      else
+      {
+        GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+                    _("Received a PING message with validation bug from `%s'\n"),
+                    GNUNET_i2s (sender));
+      }
+    }
+  }
+  else
+  {
+    addrend = NULL;             /* make gcc happy */
+    slen = 0;
+    static struct GNUNET_CRYPTO_RsaSignature no_address_signature;
+    static struct GNUNET_TIME_Absolute no_address_signature_expiration;
+
+    sig_cache = &no_address_signature;
+    sig_cache_exp = &no_address_signature_expiration;
+  }
+
+  pong = GNUNET_malloc (sizeof (struct TransportPongMessage) + alen + slen);
+  pong->header.size =
+      htons (sizeof (struct TransportPongMessage) + alen + slen);
+  pong->header.type = htons (GNUNET_MESSAGE_TYPE_TRANSPORT_PONG);
+  pong->purpose.size =
+      htonl (sizeof (struct GNUNET_CRYPTO_RsaSignaturePurpose) +
+             sizeof (uint32_t) + sizeof (struct GNUNET_TIME_AbsoluteNBO) +
+             alen + slen);
+  pong->purpose.purpose = htonl (GNUNET_SIGNATURE_PURPOSE_TRANSPORT_PONG_OWN);
+  pong->challenge = ping->challenge;
+  pong->addrlen = htonl (alen + slen);
+  memcpy (&pong[1], addr, slen);
+#if KEEP_093_COMPATIBILITY
+  if (GNUNET_YES == buggy)
+  {
+    int idsize = sizeof (GST_my_identity);
+    if (alen <= idsize)
+    {
+      memcpy (&((char *) &pong[1])[slen], &GST_my_identity, alen);
+    }
+    else if (alen <= (idsize + strlen (address.transport_name) + 1))
+    {
+      memcpy (&((char *) &pong[1])[slen], &GST_my_identity, alen);
+      memcpy (&((char *) &pong[1])[slen + idsize], address.transport_name, alen-idsize);
+    }
+    else
+    {
+      /* If this would happen, we would have a inconsistent PING we cannot reproduce */
+      GNUNET_free (pong);
+      return;
+    }
+
+    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Creating buggy PONG signature to indicate ownership.\n");
+    pong->expiration = GNUNET_TIME_absolute_hton (GNUNET_TIME_relative_to_absolute (PONG_SIGNATURE_LIFETIME));
+    GNUNET_assert (GNUNET_OK ==
+                   GNUNET_CRYPTO_rsa_sign (GST_my_private_key, &pong->purpose,
+                                           &pong->signature));
+  }
+  else
+  {
+#endif
+    memcpy (&((char *) &pong[1])[slen], addrend, alen);
+    if (GNUNET_TIME_absolute_get_remaining (*sig_cache_exp).rel_value <
+        PONG_SIGNATURE_LIFETIME.rel_value / 4)
+    {
+      /* create / update cached sig */
+      GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+                  "Creating PONG signature to indicate ownership.\n");
+      *sig_cache_exp = GNUNET_TIME_relative_to_absolute (PONG_SIGNATURE_LIFETIME);
+      pong->expiration = GNUNET_TIME_absolute_hton (*sig_cache_exp);
+      GNUNET_assert (GNUNET_OK ==
+                     GNUNET_CRYPTO_rsa_sign (GST_my_private_key, &pong->purpose,
+                                             sig_cache));
+    }
+    else
+    {
+      pong->expiration = GNUNET_TIME_absolute_hton (*sig_cache_exp);
+    }
+    pong->signature = *sig_cache;
+
+#if KEEP_093_COMPATIBILITY
+  }
+#endif
+
+  GNUNET_assert (GNUNET_OK == GNUNET_CRYPTO_rsa_verify (GNUNET_SIGNATURE_PURPOSE_TRANSPORT_PONG_OWN,
+                            &pong->purpose, &pong->signature,
+                            &GST_my_public_key));
+
+  GNUNET_assert (sender_address != NULL);
+
+  /* first see if the session we got this PING from can be used to transmit
+   * a response reliably */
+  papi = GST_plugins_find (sender_address->transport_name);
+  if (papi == NULL)
+    ret = -1;
+  else
+  {
+    GNUNET_assert (papi->send != NULL);
+    GNUNET_assert (papi->get_session != NULL);
+
+    if (session == NULL)
+    {
+      session = papi->get_session (papi->cls, sender_address);
+    }
+    if (session == NULL)
+    {
+      GNUNET_break (0);
+      ret = -1;
+    }
+    else
+    {
+      ret = papi->send (papi->cls, session,
+                        (const char *) pong, ntohs (pong->header.size),
+                        PONG_PRIORITY, ACCEPTABLE_PING_DELAY,
+                        NULL, NULL);
+    }
+  }
+  if (ret != -1)
+  {
+    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+                "Transmitted PONG to `%s' via reliable mechanism\n",
+                GNUNET_i2s (sender));
+    /* done! */
+    GNUNET_STATISTICS_update (GST_stats,
+                              gettext_noop
+                              ("# PONGs unicast via reliable transport"), 1,
+                              GNUNET_NO);
+    GNUNET_free (pong);
+    return;
+  }
+
+  /* no reliable method found, try transmission via all known addresses */
+  GNUNET_STATISTICS_update (GST_stats,
+                            gettext_noop
+                            ("# PONGs multicast to all available addresses"), 1,
+                            GNUNET_NO);
+  GST_validation_get_addresses (sender, &multicast_pong, pong);
+  GNUNET_free (pong);
 }
 
 
 /**
- * We've received a PONG.  Check if it matches a pending PING and
- * mark the respective address as confirmed.
- *
- * @param sender peer sending the PONG
- * @param hdr the PONG
- * @param plugin_name name of plugin that received the PONG
- * @param sender_address address of the sender as known to the plugin, NULL
- *                       if we did not initiate the connection
- * @param sender_address_len number of bytes in sender_address
+ * Context for the 'validate_address' function
  */
-void
-GST_validation_handle_pong (const struct GNUNET_PeerIdentity *sender,
-                           const struct GNUNET_MessageHeader *hdr,
-                           const char *plugin_name,
-                           const void *sender_address,
-                           size_t sender_address_len)
+struct ValidateAddressContext
 {
-}
+  /**
+   * Hash of the public key of the peer whose address is being validated.
+   */
+  struct GNUNET_PeerIdentity pid;
+
+  /**
+   * Public key of the peer whose address is being validated.
+   */
+  struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded public_key;
+};
 
 
 /**
  * Iterator callback to go over all addresses and try to validate them
  * (unless blocked or already validated).
  *
- * @param cls pointer to the 'struct PeerIdentity' of the peer
- * @param tname name of the transport
+ * @param cls pointer to a 'struct ValidateAddressContext'
+ * @param address the address
  * @param expiration expiration time
- * @param addr the address
- * @param addrlen length of the address
  * @return GNUNET_OK (keep the address)
  */
 static int
-validate_address (void *cls,
-                 const char *tname,
-                 struct GNUNET_TIME_Absolute expiration,
-                 const void *addr, 
-                 uint16_t addrlen)
+validate_address_iterator (void *cls,
+                           const struct GNUNET_HELLO_Address *address,
+                           struct GNUNET_TIME_Absolute expiration)
 {
-  struct GNUNET_PeerIdentity *pid = cls;
+  const struct ValidateAddressContext *vac = cls;
   struct ValidationEntry *ve;
-  struct TransportPingMessage ping;
-  struct GNUNET_TRANSPORT_PluginFunctions *papi;
-  ssize_t ret;
-  size_t tsize;
-  size_t slen;
 
   if (GNUNET_TIME_absolute_get_remaining (expiration).rel_value == 0)
-    return GNUNET_OK; /* expired */
-  ve = find_validation_entry (pid, tname, addr, addrlen);
-  if (GNUNET_TIME_absolute_get_remaining (ve->validation_block).rel_value > 0)
-    return GNUNET_OK; /* blocked */
-  if (GNUNET_TIME_absolute_get_remaining (ve->valid_until).rel_value > 0)
-    return GNUNET_OK; /* valid */
-  ve->validation_block = GNUNET_TIME_relative_to_absolute (MAX_REVALIDATION_FREQUENCY);
+    return GNUNET_OK;           /* expired */
+  ve = find_validation_entry (&vac->public_key, address);
+  if (GNUNET_SCHEDULER_NO_TASK == ve->revalidation_task)
+    ve->revalidation_task = GNUNET_SCHEDULER_add_now (&revalidate_address, ve);
+  return GNUNET_OK;
+}
 
-  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
-             "Transmitting plain PING to `%s'\n",
-             GNUNET_i2s (pid));  
-  ping.header.size = htons(sizeof(struct TransportPingMessage));
-  ping.header.type = htons(GNUNET_MESSAGE_TYPE_TRANSPORT_PING);
-  ping.challenge = htonl(ve->challenge);
-  ping.target = *pid;
-  
-  slen = strlen(ve->transport_name) + 1;
-  tsize = sizeof(struct TransportPingMessage) + ve->addrlen + slen;
+
+/**
+ * Add the validated peer address to the HELLO.
+ *
+ * @param cls the 'struct ValidationEntry' with the validated address
+ * @param max space in buf
+ * @param buf where to add the address
+ * @return number of bytes written, 0 to signal the
+ *         end of the iteration.
+ */
+static size_t
+add_valid_peer_address (void *cls, size_t max, void *buf)
+{
+  struct ValidationEntry *ve = cls;
+
+  if (GNUNET_YES == ve->copied)
+    return 0;                   /* terminate */
+  ve->copied = GNUNET_YES;
+  return GNUNET_HELLO_add_address (ve->address, ve->valid_until, buf, max);
+}
+
+
+/**
+ * We've received a PONG.  Check if it matches a pending PING and
+ * mark the respective address as confirmed.
+ *
+ * @param sender peer sending the PONG
+ * @param hdr the PONG
+ */
+void
+GST_validation_handle_pong (const struct GNUNET_PeerIdentity *sender,
+                            const struct GNUNET_MessageHeader *hdr)
+{
+  const struct TransportPongMessage *pong;
+  struct ValidationEntry *ve;
+  const char *tname;
+  const char *addr;
+  size_t addrlen;
+  size_t slen;
+  size_t size;
+  struct GNUNET_HELLO_Message *hello;
+  struct GNUNET_HELLO_Address address;
+
+  if (ntohs (hdr->size) < sizeof (struct TransportPongMessage))
   {
-    char message_buf[tsize];
+    GNUNET_break_op (0);
+    return;
+  }
+  GNUNET_STATISTICS_update (GST_stats,
+                            gettext_noop ("# PONG messages received"), 1,
+                            GNUNET_NO);
+
+  pong = (const struct TransportPongMessage *) hdr;
+  tname = (const char *) &pong[1];
+  size = ntohs (hdr->size) - sizeof (struct TransportPongMessage);
+  addr = memchr (tname, '\0', size);
+  if (NULL == addr)
+  {
+    GNUNET_break_op (0);
+    return;
+  }
+  addr++;
+  slen = strlen (tname) + 1;
+  addrlen = size - slen;
+  address.peer = *sender;
+  address.address = addr;
+  address.address_length = addrlen;
+  address.transport_name = tname;
+  ve = find_validation_entry (NULL, &address);
+  if ((NULL == ve) || (ve->expecting_pong == GNUNET_NO))
+  {
+    GNUNET_STATISTICS_update (GST_stats,
+                              gettext_noop
+                              ("# PONGs dropped, no matching pending validation"),
+                              1, GNUNET_NO);
+    return;
+  }
+  /* now check that PONG is well-formed */
+  if (0 != memcmp (&ve->pid, sender, sizeof (struct GNUNET_PeerIdentity)))
+  {
+    GNUNET_break_op (0);
+    return;
+  }
 
-    memcpy(message_buf, &ping, sizeof (struct TransportPingMessage));
-    memcpy(&message_buf[sizeof (struct TransportPingMessage)],
-          ve->transport_name,
-          slen);
-    memcpy(&message_buf[sizeof (struct TransportPingMessage) + slen],
-          ve->addr,
-          ve->addrlen);
-    papi = GST_plugins_find (ve->transport_name);
-    ret = papi->send (papi->cls,
-                     pid,
-                     message_buf,
-                     tsize,
-                     PING_PRIORITY,
-                     HELLO_VERIFICATION_TIMEOUT,
-                     NULL /* no session */,
-                     ve->addr,
-                     ve->addrlen,
-                     GNUNET_YES,
-                     NULL, NULL);
+  if (GNUNET_OK !=
+      GNUNET_CRYPTO_rsa_verify (GNUNET_SIGNATURE_PURPOSE_TRANSPORT_PONG_OWN,
+                                &pong->purpose, &pong->signature,
+                                &ve->public_key))
+  {
+    GNUNET_break_op (0);
+    return;
   }
-  if (-1 != ret)
-    {
-      ve->send_time = GNUNET_TIME_absolute_get ();
-      GNUNET_STATISTICS_update (GST_stats,
-                               gettext_noop ("# PING without HELLO messages sent"),
-                               1,
-                               GNUNET_NO);
-    }
-  return GNUNET_OK;
-}
 
+  if (GNUNET_TIME_absolute_get_remaining
+      (GNUNET_TIME_absolute_ntoh (pong->expiration)).rel_value == 0)
+  {
+    GNUNET_STATISTICS_update (GST_stats,
+                              gettext_noop
+                              ("# PONGs dropped, signature expired"), 1,
+                              GNUNET_NO);
+    return;
+  }
+  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+              "Address validated for peer `%s' with plugin `%s': `%s'\n",
+              GNUNET_i2s (sender), tname, GST_plugins_a2s (ve->address));
+  /* validity achieved, remember it! */
+  ve->expecting_pong = GNUNET_NO;
+  ve->valid_until = GNUNET_TIME_relative_to_absolute (HELLO_ADDRESS_EXPIRATION);
+  ve->latency = GNUNET_TIME_absolute_get_duration (ve->send_time);
+  {
+    struct GNUNET_ATS_Information ats;
+    ats.type = htonl (GNUNET_ATS_QUALITY_NET_DELAY);
+    ats.value = htonl ((uint32_t) ve->latency.rel_value);
+    GNUNET_ATS_address_add (GST_ats, ve->address, NULL, &ats, 1);
+  }
+  /* build HELLO to store in PEERINFO */
+  ve->copied = GNUNET_NO;
+  hello = GNUNET_HELLO_create (&ve->public_key, &add_valid_peer_address, ve);
+  GNUNET_PEERINFO_add_peer (GST_peerinfo, hello, NULL, NULL);
+  GNUNET_free (hello);
+}
 
 
 /**
@@ -605,28 +1180,41 @@ validate_address (void *cls,
 void
 GST_validation_handle_hello (const struct GNUNET_MessageHeader *hello)
 {
-  const struct GNUNET_HELLO_Message* hm = (const struct GNUNET_HELLO_Message*) hello;
-  struct GNUNET_PeerIdentity pid;
+  const struct GNUNET_HELLO_Message *hm =
+      (const struct GNUNET_HELLO_Message *) hello;
+  struct ValidateAddressContext vac;
+  struct GNUNET_HELLO_Message *h;
 
-  if (GNUNET_OK !=
-      GNUNET_HELLO_get_id (hm, &pid))    
-    {
-      /* malformed HELLO */
-      GNUNET_break (0);
-      return; 
-    }
+  if ((GNUNET_OK != GNUNET_HELLO_get_id (hm, &vac.pid)) ||
+      (GNUNET_OK != GNUNET_HELLO_get_key (hm, &vac.public_key)))
+  {
+    /* malformed HELLO */
+    GNUNET_break (0);
+    return;
+  }
+  if (0 ==
+      memcmp (&GST_my_identity, &vac.pid, sizeof (struct GNUNET_PeerIdentity)))
+    return;
+  /* Add peer identity without addresses to peerinfo service */
+  h = GNUNET_HELLO_create (&vac.public_key, NULL, NULL);
+  GNUNET_PEERINFO_add_peer (GST_peerinfo, h, NULL, NULL);
+
+  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+              _("Adding `%s' without addresses for peer `%s'\n"), "HELLO",
+              GNUNET_i2s (&vac.pid));
+
+  GNUNET_free (h);
   GNUNET_assert (NULL ==
-                GNUNET_HELLO_iterate_addresses (hm,
-                                                GNUNET_NO,
-                                                &validate_address,
-                                                &pid));
+                 GNUNET_HELLO_iterate_addresses (hm, GNUNET_NO,
+                                                 &validate_address_iterator,
+                                                 &vac));
 }
 
 
 /**
- * Opaque handle to stop incremental validation address callbacks.
+ * Closure for 'iterate_addresses'
  */
-struct GST_ValidationIteratorContext
+struct IteratorContext
 {
   /**
    * Function to call on each address.
@@ -638,10 +1226,6 @@ struct GST_ValidationIteratorContext
    */
   void *cb_cls;
 
-  /**
-   * Which peer are we monitoring?
-   */   
-  struct GNUNET_PeerIdentity target;
 };
 
 
@@ -654,20 +1238,13 @@ struct GST_ValidationIteratorContext
  * @return GNUNET_OK (continue to iterate)
  */
 static int
-iterate_addresses (void *cls,
-                  const GNUNET_HashCode *key,
-                  void *value)
+iterate_addresses (void *cls, const struct GNUNET_HashCode * key, void *value)
 {
-  struct GST_ValidationIteratorContext *vic = cls;
+  struct IteratorContext *ic = cls;
   struct ValidationEntry *ve = value;
 
-  vic->cb (vic->cb_cls,
-          &ve->pid,
-          ve->valid_until,
-          ve->validation_block,
-          ve->transport_name,
-          ve->addr,
-          ve->addrlen);
+  ic->cb (ic->cb_cls, &ve->public_key, ve->valid_until, ve->revalidation_block,
+          ve->address);
   return GNUNET_OK;
 }
 
@@ -677,55 +1254,116 @@ iterate_addresses (void *cls,
  * Can either give a snapshot (synchronous API) or be continuous.
  *
  * @param target peer information is requested for
- * @param snapshot_only GNUNET_YES to iterate over addresses once, GNUNET_NO to
- *                      continue to give information about addresses as it evolves
  * @param cb function to call; will not be called after this function returns
- *                             if snapshot_only is GNUNET_YES
  * @param cb_cls closure for 'cb'
- * @return context to cancel, NULL if 'snapshot_only' is GNUNET_YES
  */
-struct GST_ValidationIteratorContext *
+void
 GST_validation_get_addresses (const struct GNUNET_PeerIdentity *target,
-                             int snapshot_only,
-                             GST_ValidationAddressCallback cb,
-                             void *cb_cls)
+                              GST_ValidationAddressCallback cb, void *cb_cls)
 {
-  struct GST_ValidationIteratorContext *vic;
+  struct IteratorContext ic;
 
-  vic = GNUNET_malloc (sizeof (struct GST_ValidationIteratorContext));
-  vic->cb = cb;
-  vic->cb_cls = cb_cls;
-  vic->target = *target;
+  ic.cb = cb;
+  ic.cb_cls = cb_cls;
   GNUNET_CONTAINER_multihashmap_get_multiple (validation_map,
-                                             &target->hashPubKey,
-                                             &iterate_addresses,
-                                             vic);
-  if (GNUNET_YES == snapshot_only)
+                                              &target->hashPubKey,
+                                              &iterate_addresses, &ic);
+}
+
+
+/**
+ * Update if we are using an address for a connection actively right now.
+ * Based on this, the validation module will measure latency for the
+ * address more or less often.
+ *
+ * @param address the address
+ * @param session the session
+ * @param in_use GNUNET_YES if we are now using the address for a connection,
+ *               GNUNET_NO if we are no longer using the address for a connection
+ * @param line line of caller just for DEBUGGING!
+ */
+void
+GST_validation_set_address_use (const struct GNUNET_HELLO_Address *address,
+                                struct Session *session,
+                                int in_use,
+                                int line)
+{
+  struct ValidationEntry *ve;
+
+  if (NULL != address)
+    ve = find_validation_entry (NULL, address);
+  else
+    ve = NULL;                  /* FIXME: lookup based on session... */
+  if (NULL == ve)
+  {
+    /* this can happen for inbound connections (sender_address_len == 0); */
+    return;
+  }
+  if (ve->in_use == in_use)
+  {
+
+    if (GNUNET_YES == in_use)
+    {
+      GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                  "Error setting address in use for peer `%s' `%s' to USED: set last time by %i, called now by %i\n",
+                  GNUNET_i2s (&address->peer), GST_plugins_a2s (address),
+                  ve->last_line_set_to_yes, line);
+    }
+    if (GNUNET_NO == in_use)
     {
-      GNUNET_free (vic);
-      return NULL;
+      GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                  "Error setting address in use for peer `%s' `%s' to NOT_USED: set last time by %i, called now by %i\n",
+                  GNUNET_i2s (&address->peer), GST_plugins_a2s (address),
+                  ve->last_line_set_to_no, line);
     }
-  GNUNET_CONTAINER_multihashmap_put (notify_map,
-                                    &target->hashPubKey,
-                                    vic,
-                                    GNUNET_CONTAINER_MULTIHASHMAPOPTION_MULTIPLE);
-  return vic;
+  }
+
+  if (GNUNET_YES == in_use)
+  {
+    ve->last_line_set_to_yes = line;
+  }
+  if (GNUNET_NO == in_use)
+  {
+    ve->last_line_set_to_no = line;
+  }
+
+  GNUNET_break (ve->in_use != in_use);  /* should be different... */
+  ve->in_use = in_use;
+  if (in_use == GNUNET_YES)
+  {
+    /* from now on, higher frequeny, so reschedule now */
+    GNUNET_SCHEDULER_cancel (ve->revalidation_task);
+    ve->revalidation_task = GNUNET_SCHEDULER_add_now (&revalidate_address, ve);
+  }
 }
 
 
 /**
- * Cancel an active validation address iteration.
+ * Query validation about the latest observed latency on a given
+ * address.
  *
- * @param ctx the context of the operation that is cancelled
+ * @param sender peer
+ * @param address the address
+ * @param session session
+ * @return observed latency of the address, FOREVER if the address was
+ *         never successfully validated
  */
-void
-GST_validation_get_addresses_cancel (struct GST_ValidationIteratorContext *ctx)
+struct GNUNET_TIME_Relative
+GST_validation_get_address_latency (const struct GNUNET_PeerIdentity *sender,
+                                    const struct GNUNET_HELLO_Address *address,
+                                    struct Session *session)
 {
-  GNUNET_assert (GNUNET_OK ==
-                GNUNET_CONTAINER_multihashmap_remove (notify_map,
-                                                      &ctx->target.hashPubKey,
-                                                      ctx));
-  GNUNET_free (ctx);
+  struct ValidationEntry *ve;
+
+  if (NULL == address)
+  {
+    GNUNET_break (0);           // FIXME: support having latency only with session...
+    return GNUNET_TIME_UNIT_FOREVER_REL;
+  }
+  ve = find_validation_entry (NULL, address);
+  if (NULL == ve)
+    return GNUNET_TIME_UNIT_FOREVER_REL;
+  return ve->latency;
 }