-improve UDP logging
[oweals/gnunet.git] / src / core / gnunet-service-core_kx.c
index f7fbfcf68ab79720a85b163d0a193ad44e09c785..fc242b171dc6862385771011542ea13efd271654 100644 (file)
@@ -1,6 +1,6 @@
 /*
      This file is part of GNUnet.
-     (C) 2009, 2010, 2011, 2012 Christian Grothoff (and other contributing authors)
+     Copyright (C) 2009-2013 Christian Grothoff (and other contributing authors)
 
      GNUnet is free software; you can redistribute it and/or modify
      it under the terms of the GNU General Public License as published
@@ -77,20 +77,20 @@ struct EphemeralKeyMessage
 {
 
   /**
-   * Message type is CORE_EPHEMERAL_KEY.
+   * Message type is #GNUNET_MESSAGE_TYPE_CORE_EPHEMERAL_KEY.
    */
   struct GNUNET_MessageHeader header;
 
   /**
-   * Status of the sender (should be in "enum PeerStateMachine"), nbo.
+   * Status of the sender (should be in `enum PeerStateMachine`), nbo.
    */
   int32_t sender_status GNUNET_PACKED;
 
   /**
-   * An ECC signature of the 'origin' asserting the validity of
+   * An ECC signature of the @e origin_identity asserting the validity of
    * the given ephemeral key.
    */
-  struct GNUNET_CRYPTO_EccSignature signature;
+  struct GNUNET_CRYPTO_EddsaSignature signature;
 
   /**
    * Information about what is being signed.
@@ -101,22 +101,21 @@ struct EphemeralKeyMessage
    * At what time was this key created (beginning of validity).
    */
   struct GNUNET_TIME_AbsoluteNBO creation_time;
-  
+
   /**
    * When does the given ephemeral key expire (end of validity).
    */
   struct GNUNET_TIME_AbsoluteNBO expiration_time;
 
   /**
-   * Ephemeral public ECC key (always for NIST P-521) encoded in a format suitable
-   * for network transmission as created using 'gcry_sexp_sprint'.
+   * Ephemeral public ECC key.
    */
-  struct GNUNET_CRYPTO_EccPublicKeyBinaryEncoded ephemeral_key;  
+  struct GNUNET_CRYPTO_EcdhePublicKey ephemeral_key;
 
   /**
    * Public key of the signing peer (persistent version, not the ephemeral public key).
    */
-  struct GNUNET_CRYPTO_EccPublicKeyBinaryEncoded origin_public_key;
+  struct GNUNET_PeerIdentity origin_identity;
 
 };
 
@@ -129,7 +128,7 @@ struct EphemeralKeyMessage
 struct PingMessage
 {
   /**
-   * Message type is CORE_PING.
+   * Message type is #GNUNET_MESSAGE_TYPE_CORE_PING.
    */
   struct GNUNET_MessageHeader header;
 
@@ -157,7 +156,7 @@ struct PingMessage
 struct PongMessage
 {
   /**
-   * Message type is CORE_PONG.
+   * Message type is #GNUNET_MESSAGE_TYPE_CORE_PONG.
    */
   struct GNUNET_MessageHeader header;
 
@@ -192,7 +191,7 @@ struct PongMessage
 struct EncryptedMessage
 {
   /**
-   * Message type is either CORE_ENCRYPTED_MESSAGE.
+   * Message type is either #GNUNET_MESSAGE_TYPE_CORE_ENCRYPTED_MESSAGE.
    */
   struct GNUNET_MessageHeader header;
 
@@ -231,53 +230,12 @@ GNUNET_NETWORK_STRUCT_END
 
 
 /**
- * Number of bytes (at the beginning) of "struct EncryptedMessage"
+ * Number of bytes (at the beginning) of `struct EncryptedMessage`
  * that are NOT encrypted.
  */
 #define ENCRYPTED_HEADER_SIZE (offsetof(struct EncryptedMessage, sequence_number))
 
 
-/**
- * State machine for our P2P encryption handshake.  Everyone starts in
- * "DOWN", if we receive the other peer's key (other peer initiated)
- * we start in state RECEIVED (since we will immediately send our
- * own); otherwise we start in SENT.  If we get back a PONG from
- * within either state, we move up to CONFIRMED (the PONG will always
- * be sent back encrypted with the key we sent to the other peer).
- */
-enum KxStateMachine
-{
-  /**
-   * No handshake yet.
-   */
-  KX_STATE_DOWN,
-
-  /**
-   * We've sent our session key.
-   */
-  KX_STATE_KEY_SENT,
-
-  /**
-   * We've received the other peers session key.
-   */
-  KX_STATE_KEY_RECEIVED,
-
-  /**
-   * The other peer has confirmed our session key + PING with a PONG
-   * message encrypted with his session key (which we got).  Key
-   * exchange is done.
-   */
-  KX_STATE_UP,
-
-  /**
-   * We're rekeying, so we have sent the other peer our new ephemeral
-   * key, but we did not get a matching PONG yet.
-   */
-  KX_STATE_REKEY_SENT
-
-};
-
-
 /**
  * Information about the status of a key exchange with another peer.
  */
@@ -304,17 +262,22 @@ struct GSC_KeyExchangeInfo
    */
   struct PingMessage ping;
 
+  /**
+   * Ephemeral public ECC key of the other peer.
+   */
+  struct GNUNET_CRYPTO_EcdhePublicKey other_ephemeral_key;
+
   /**
    * Key we use to encrypt our messages for the other peer
    * (initialized by us when we do the handshake).
    */
-  struct GNUNET_CRYPTO_AesSessionKey encrypt_key;
+  struct GNUNET_CRYPTO_SymmetricSessionKey encrypt_key;
 
   /**
    * Key we use to decrypt messages from the other peer
    * (given to us by the other peer during the handshake).
    */
-  struct GNUNET_CRYPTO_AesSessionKey decrypt_key;
+  struct GNUNET_CRYPTO_SymmetricSessionKey decrypt_key;
 
   /**
    * At what time did the other peer generate the decryption key?
@@ -326,6 +289,11 @@ struct GSC_KeyExchangeInfo
    */
   struct GNUNET_TIME_Absolute timeout;
 
+  /**
+   * What was the last timeout we informed our monitors about?
+   */
+  struct GNUNET_TIME_Absolute last_notify_timeout;
+
   /**
    * At what frequency are we currently re-trying SET_KEY messages?
    */
@@ -334,12 +302,12 @@ struct GSC_KeyExchangeInfo
   /**
    * ID of task used for re-trying SET_KEY and PING message.
    */
-  GNUNET_SCHEDULER_TaskIdentifier retry_set_key_task;
+  struct GNUNET_SCHEDULER_Task * retry_set_key_task;
 
   /**
    * ID of task used for sending keep-alive pings.
    */
-  GNUNET_SCHEDULER_TaskIdentifier keep_alive_task;
+  struct GNUNET_SCHEDULER_Task * keep_alive_task;
 
   /**
    * Bit map indicating which of the 32 sequence numbers before the last
@@ -366,7 +334,7 @@ struct GSC_KeyExchangeInfo
   /**
    * What is our connection status?
    */
-  enum KxStateMachine status;
+  enum GNUNET_CORE_KxState status;
 
 };
 
@@ -374,23 +342,18 @@ struct GSC_KeyExchangeInfo
 /**
  * Our private key.
  */
-static struct GNUNET_CRYPTO_EccPrivateKey *my_private_key;
+static struct GNUNET_CRYPTO_EddsaPrivateKey *my_private_key;
 
 /**
  * Our ephemeral private key.
  */
-static struct GNUNET_CRYPTO_EccPrivateKey *my_ephemeral_key;
+static struct GNUNET_CRYPTO_EcdhePrivateKey *my_ephemeral_key;
 
 /**
  * Current message we send for a key exchange.
  */
 static struct EphemeralKeyMessage current_ekm;
 
-/**
- * Our public key.
- */
-static struct GNUNET_CRYPTO_EccPublicKeyBinaryEncoded my_public_key;
-
 /**
  * Our message stream tokenizer (for encrypted payload).
  */
@@ -409,8 +372,76 @@ static struct GSC_KeyExchangeInfo *kx_tail;
 /**
  * Task scheduled for periodic re-generation (and thus rekeying) of our
  * ephemeral key.
- */ 
-static GNUNET_SCHEDULER_TaskIdentifier rekey_task;
+ */
+static struct GNUNET_SCHEDULER_Task * rekey_task;
+
+/**
+ * Notification context for all monitors.
+ */
+static struct GNUNET_SERVER_NotificationContext *nc;
+
+
+/**
+ * Inform the given monitor about the KX state of
+ * the given peer.
+ *
+ * @param client client to inform
+ * @param kx key exchange state to inform about
+ */
+static void
+monitor_notify (struct GNUNET_SERVER_Client *client,
+                struct GSC_KeyExchangeInfo *kx)
+{
+  struct MonitorNotifyMessage msg;
+
+  msg.header.type = htons (GNUNET_MESSAGE_TYPE_CORE_MONITOR_NOTIFY);
+  msg.header.size = htons (sizeof (msg));
+  msg.state = htonl ((uint32_t) kx->status);
+  msg.peer = kx->peer;
+  msg.timeout = GNUNET_TIME_absolute_hton (kx->timeout);
+  GNUNET_SERVER_notification_context_unicast (nc,
+                                              client,
+                                              &msg.header,
+                                              GNUNET_NO);
+}
+
+
+/**
+ * Calculate seed value we should use for a message.
+ *
+ * @param kx key exchange context
+ */
+static uint32_t
+calculate_seed (struct GSC_KeyExchangeInfo *kx)
+{
+  /* Note: may want to make this non-random and instead
+     derive from key material to avoid having an undetectable
+     side-channel */
+  return htonl (GNUNET_CRYPTO_random_u32
+               (GNUNET_CRYPTO_QUALITY_NONCE, UINT32_MAX));
+}
+
+
+/**
+ * Inform all monitors about the KX state of the given peer.
+ *
+ * @param kx key exchange state to inform about
+ */
+static void
+monitor_notify_all (struct GSC_KeyExchangeInfo *kx)
+{
+  struct MonitorNotifyMessage msg;
+
+  msg.header.type = htons (GNUNET_MESSAGE_TYPE_CORE_MONITOR_NOTIFY);
+  msg.header.size = htons (sizeof (msg));
+  msg.state = htonl ((uint32_t) kx->status);
+  msg.peer = kx->peer;
+  msg.timeout = GNUNET_TIME_absolute_hton (kx->timeout);
+  GNUNET_SERVER_notification_context_broadcast (nc,
+                                                &msg.header,
+                                                GNUNET_NO);
+  kx->last_notify_timeout = kx->timeout;
+}
 
 
 /**
@@ -422,13 +453,16 @@ static GNUNET_SCHEDULER_TaskIdentifier rekey_task;
  */
 static void
 derive_auth_key (struct GNUNET_CRYPTO_AuthKey *akey,
-                 const struct GNUNET_CRYPTO_AesSessionKey *skey, uint32_t seed)
+                 const struct GNUNET_CRYPTO_SymmetricSessionKey *skey,
+                 uint32_t seed)
 {
   static const char ctx[] = "authentication key";
 
-  GNUNET_CRYPTO_hmac_derive_key (akey, skey, &seed, sizeof (seed), &skey->key,
-                                 sizeof (skey->key), ctx,
-                                 sizeof (ctx), NULL);
+  GNUNET_CRYPTO_hmac_derive_key (akey, skey,
+                                 &seed, sizeof (seed),
+                                 skey, sizeof (struct GNUNET_CRYPTO_SymmetricSessionKey),
+                                 ctx, sizeof (ctx),
+                                 NULL);
 }
 
 
@@ -441,16 +475,16 @@ derive_auth_key (struct GNUNET_CRYPTO_AuthKey *akey,
  * @param identity identity of the other peer to use
  */
 static void
-derive_iv (struct GNUNET_CRYPTO_AesInitializationVector *iv,
-           const struct GNUNET_CRYPTO_AesSessionKey *skey, uint32_t seed,
+derive_iv (struct GNUNET_CRYPTO_SymmetricInitializationVector *iv,
+           const struct GNUNET_CRYPTO_SymmetricSessionKey *skey, uint32_t seed,
            const struct GNUNET_PeerIdentity *identity)
 {
   static const char ctx[] = "initialization vector";
 
-  GNUNET_CRYPTO_aes_derive_iv (iv, skey, &seed, sizeof (seed),
-                               &identity->hashPubKey.bits,
-                               sizeof (identity->hashPubKey.bits), ctx,
-                               sizeof (ctx), NULL);
+  GNUNET_CRYPTO_symmetric_derive_iv (iv, skey, &seed, sizeof (seed),
+                                    identity,
+                                    sizeof (struct GNUNET_PeerIdentity), ctx,
+                                    sizeof (ctx), NULL);
 }
 
 
@@ -464,16 +498,18 @@ derive_iv (struct GNUNET_CRYPTO_AesInitializationVector *iv,
  * @param identity identity of the other peer to use
  */
 static void
-derive_pong_iv (struct GNUNET_CRYPTO_AesInitializationVector *iv,
-                const struct GNUNET_CRYPTO_AesSessionKey *skey, uint32_t seed,
+derive_pong_iv (struct GNUNET_CRYPTO_SymmetricInitializationVector *iv,
+                const struct GNUNET_CRYPTO_SymmetricSessionKey *skey, uint32_t seed,
                 uint32_t challenge, const struct GNUNET_PeerIdentity *identity)
 {
   static const char ctx[] = "pong initialization vector";
 
-  GNUNET_CRYPTO_aes_derive_iv (iv, skey, &seed, sizeof (seed),
-                               &identity->hashPubKey.bits,
-                               sizeof (identity->hashPubKey.bits), &challenge,
-                               sizeof (challenge), ctx, sizeof (ctx), NULL);
+  GNUNET_CRYPTO_symmetric_derive_iv (iv, skey, &seed, sizeof (seed),
+                                    identity,
+                                    sizeof (struct GNUNET_PeerIdentity),
+                                    &challenge, sizeof (challenge),
+                                    ctx, sizeof (ctx),
+                                    NULL);
 }
 
 
@@ -483,19 +519,19 @@ derive_pong_iv (struct GNUNET_CRYPTO_AesInitializationVector *iv,
  * @param sender peer identity of the sender
  * @param receiver peer identity of the sender
  * @param key_material high entropy key material to use
- * @param skey set to derived session key 
+ * @param skey set to derived session key
  */
 static void
 derive_aes_key (const struct GNUNET_PeerIdentity *sender,
                const struct GNUNET_PeerIdentity *receiver,
                const struct GNUNET_HashCode *key_material,
-               struct GNUNET_CRYPTO_AesSessionKey *skey)
+               struct GNUNET_CRYPTO_SymmetricSessionKey *skey)
 {
   static const char ctx[] = "aes key generation vector";
 
-  GNUNET_CRYPTO_kdf (skey, sizeof (struct GNUNET_CRYPTO_AesSessionKey),
+  GNUNET_CRYPTO_kdf (skey, sizeof (struct GNUNET_CRYPTO_SymmetricSessionKey),
                     ctx, sizeof (ctx),
-                    skey, sizeof (struct GNUNET_CRYPTO_AesSessionKey),
+                    key_material, sizeof (struct GNUNET_HashCode),
                     sender, sizeof (struct GNUNET_PeerIdentity),
                     receiver, sizeof (struct GNUNET_PeerIdentity),
                     NULL);
@@ -503,19 +539,19 @@ derive_aes_key (const struct GNUNET_PeerIdentity *sender,
 
 
 /**
- * Encrypt size bytes from in and write the result to out.  Use the
- * key for outbound traffic of the given neighbour.
+ * Encrypt size bytes from @a in and write the result to @a out.  Use the
+ * @a kx key for outbound traffic of the given neighbour.
  *
  * @param kx key information context
  * @param iv initialization vector to use
  * @param in ciphertext
  * @param out plaintext
- * @param size size of in/out
- * @return GNUNET_OK on success
+ * @param size size of @a in/@a out
+ * @return #GNUNET_OK on success
  */
 static int
 do_encrypt (struct GSC_KeyExchangeInfo *kx,
-            const struct GNUNET_CRYPTO_AesInitializationVector *iv,
+            const struct GNUNET_CRYPTO_SymmetricInitializationVector *iv,
             const void *in, void *out, size_t size)
 {
   if (size != (uint16_t) size)
@@ -524,7 +560,7 @@ do_encrypt (struct GSC_KeyExchangeInfo *kx,
     return GNUNET_NO;
   }
   GNUNET_assert (size ==
-                 GNUNET_CRYPTO_aes_encrypt (in, (uint16_t) size,
+                 GNUNET_CRYPTO_symmetric_encrypt (in, (uint16_t) size,
                                             &kx->encrypt_key, iv, out));
   GNUNET_STATISTICS_update (GSC_stats, gettext_noop ("# bytes encrypted"), size,
                             GNUNET_NO);
@@ -543,20 +579,20 @@ do_encrypt (struct GSC_KeyExchangeInfo *kx,
 
 
 /**
- * Decrypt size bytes from in and write the result to out.  Use the
- * key for inbound traffic of the given neighbour.  This function does
+ * Decrypt size bytes from @a in and write the result to @a out.  Use the
+ * @a kx key for inbound traffic of the given neighbour.  This function does
  * NOT do any integrity-checks on the result.
  *
  * @param kx key information context
  * @param iv initialization vector to use
  * @param in ciphertext
  * @param out plaintext
- * @param size size of in/out
- * @return GNUNET_OK on success
+ * @param size size of @a in / @a out
+ * @return #GNUNET_OK on success
  */
 static int
 do_decrypt (struct GSC_KeyExchangeInfo *kx,
-            const struct GNUNET_CRYPTO_AesInitializationVector *iv,
+            const struct GNUNET_CRYPTO_SymmetricInitializationVector *iv,
             const void *in, void *out, size_t size)
 {
   if (size != (uint16_t) size)
@@ -564,14 +600,15 @@ do_decrypt (struct GSC_KeyExchangeInfo *kx,
     GNUNET_break (0);
     return GNUNET_NO;
   }
-  if ( (kx->status != KX_STATE_KEY_RECEIVED) && (kx->status != KX_STATE_UP) &&
-       (kx->status != KX_STATE_REKEY_SENT) )
+  if ( (kx->status != GNUNET_CORE_KX_STATE_KEY_RECEIVED) &&
+       (kx->status != GNUNET_CORE_KX_STATE_UP) &&
+       (kx->status != GNUNET_CORE_KX_STATE_REKEY_SENT) )
   {
     GNUNET_break_op (0);
     return GNUNET_SYSERR;
   }
   if (size !=
-      GNUNET_CRYPTO_aes_decrypt (in, (uint16_t) size, &kx->decrypt_key, iv,
+      GNUNET_CRYPTO_symmetric_decrypt (in, (uint16_t) size, &kx->decrypt_key, iv,
                                  out))
   {
     GNUNET_break (0);
@@ -603,18 +640,20 @@ send_key (struct GSC_KeyExchangeInfo *kx);
 
 
 /**
- * Task that will retry "send_key" if our previous attempt failed.
+ * Task that will retry #send_key() if our previous attempt failed.
  *
- * @param cls our 'struct GSC_KeyExchangeInfo'
+ * @param cls our `struct GSC_KeyExchangeInfo`
  * @param tc scheduler context
  */
 static void
-set_key_retry_task (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
+set_key_retry_task (void *cls,
+                    const struct GNUNET_SCHEDULER_TaskContext *tc)
 {
   struct GSC_KeyExchangeInfo *kx = cls;
 
-  kx->retry_set_key_task = GNUNET_SCHEDULER_NO_TASK;
+  kx->retry_set_key_task = NULL;
   kx->set_key_retry_frequency = GNUNET_TIME_STD_BACKOFF (kx->set_key_retry_frequency);
+  GNUNET_assert (GNUNET_CORE_KX_STATE_DOWN != kx->status);
   send_key (kx);
 }
 
@@ -629,13 +668,12 @@ setup_fresh_ping (struct GSC_KeyExchangeInfo *kx)
 {
   struct PingMessage pp;
   struct PingMessage *pm;
-  struct GNUNET_CRYPTO_AesInitializationVector iv;
+  struct GNUNET_CRYPTO_SymmetricInitializationVector iv;
 
   pm = &kx->ping;
   pm->header.size = htons (sizeof (struct PingMessage));
   pm->header.type = htons (GNUNET_MESSAGE_TYPE_CORE_PING);
-  pm->iv_seed =
-      GNUNET_CRYPTO_random_u32 (GNUNET_CRYPTO_QUALITY_NONCE, UINT32_MAX);
+  pm->iv_seed = calculate_seed (kx);
   derive_iv (&iv, &kx->encrypt_key, pm->iv_seed, &kx->peer);
   pp.challenge = kx->ping_challenge;
   pp.target = kx->peer;
@@ -655,21 +693,44 @@ struct GSC_KeyExchangeInfo *
 GSC_KX_start (const struct GNUNET_PeerIdentity *pid)
 {
   struct GSC_KeyExchangeInfo *kx;
+  struct GNUNET_HashCode h1;
+  struct GNUNET_HashCode h2;
 
-  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, 
+  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "Initiating key exchange with `%s'\n",
               GNUNET_i2s (pid));
   GNUNET_STATISTICS_update (GSC_stats,
                             gettext_noop ("# key exchanges initiated"), 1,
                             GNUNET_NO);
-  kx = GNUNET_malloc (sizeof (struct GSC_KeyExchangeInfo));
+  kx = GNUNET_new (struct GSC_KeyExchangeInfo);
   kx->peer = *pid;
   kx->set_key_retry_frequency = INITIAL_SET_KEY_RETRY_FREQUENCY;
   GNUNET_CONTAINER_DLL_insert (kx_head,
                               kx_tail,
                               kx);
-  kx->status = KX_STATE_KEY_SENT;
-  send_key (kx);
+  kx->status = GNUNET_CORE_KX_STATE_KEY_SENT;
+  monitor_notify_all (kx);
+  GNUNET_CRYPTO_hash (pid,
+                      sizeof (struct GNUNET_PeerIdentity),
+                      &h1);
+  GNUNET_CRYPTO_hash (&GSC_my_identity,
+                      sizeof (struct GNUNET_PeerIdentity),
+                      &h2);
+  if (0 < GNUNET_CRYPTO_hash_cmp (&h1,
+                                 &h2))
+  {
+    /* peer with "lower" identity starts KX, otherwise we typically end up
+       with both peers starting the exchange and transmit the 'set key'
+       message twice */
+    send_key (kx);
+  }
+  else
+  {
+    /* peer with "higher" identity starts a delayed  KX, if the "lower" peer
+     * does not start a KX since he sees no reasons to do so  */
+    kx->retry_set_key_task = GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_SECONDS,
+                                                           &set_key_retry_task, kx);
+  }
   return kx;
 }
 
@@ -682,18 +743,21 @@ GSC_KX_start (const struct GNUNET_PeerIdentity *pid)
 void
 GSC_KX_stop (struct GSC_KeyExchangeInfo *kx)
 {
+  GSC_SESSIONS_end (&kx->peer);
   GNUNET_STATISTICS_update (GSC_stats, gettext_noop ("# key exchanges stopped"),
                             1, GNUNET_NO);
-  if (kx->retry_set_key_task != GNUNET_SCHEDULER_NO_TASK)
+  if (kx->retry_set_key_task != NULL)
   {
     GNUNET_SCHEDULER_cancel (kx->retry_set_key_task);
-    kx->retry_set_key_task = GNUNET_SCHEDULER_NO_TASK;
+    kx->retry_set_key_task = NULL;
   }
-  if (kx->keep_alive_task != GNUNET_SCHEDULER_NO_TASK)
+  if (kx->keep_alive_task != NULL)
   {
     GNUNET_SCHEDULER_cancel (kx->keep_alive_task);
-    kx->keep_alive_task = GNUNET_SCHEDULER_NO_TASK;
+    kx->keep_alive_task = NULL;
   }
+  kx->status = GNUNET_CORE_KX_PEER_DISCONNECT;
+  monitor_notify_all (kx);
   GNUNET_CONTAINER_DLL_remove (kx_head,
                               kx_tail,
                               kx);
@@ -709,10 +773,46 @@ GSC_KX_stop (struct GSC_KeyExchangeInfo *kx)
 static void
 send_ping (struct GSC_KeyExchangeInfo *kx)
 {
-  GSC_NEIGHBOURS_transmit (&kx->peer, &kx->ping.header,
+  GSC_NEIGHBOURS_transmit (&kx->peer,
+                           &kx->ping.header,
                            MIN_PING_FREQUENCY);
 }
 
+
+/**
+ * Derive fresh session keys from the current ephemeral keys.
+ *
+ * @param kx session to derive keys for
+ */
+static void
+derive_session_keys (struct GSC_KeyExchangeInfo *kx)
+{
+  struct GNUNET_HashCode key_material;
+
+  if (GNUNET_OK !=
+      GNUNET_CRYPTO_ecc_ecdh (my_ephemeral_key,
+                             &kx->other_ephemeral_key,
+                             &key_material))
+  {
+    GNUNET_break (0);
+    return;
+  }
+  derive_aes_key (&GSC_my_identity,
+                 &kx->peer,
+                 &key_material,
+                 &kx->encrypt_key);
+  derive_aes_key (&kx->peer,
+                 &GSC_my_identity,
+                 &key_material,
+                 &kx->decrypt_key);
+  memset (&key_material, 0, sizeof (key_material));
+  /* fresh key, reset sequence numbers */
+  kx->last_sequence_number_received = 0;
+  kx->last_packets_bitmap = 0;
+  setup_fresh_ping (kx);
+}
+
+
 /**
  * We received a SET_KEY message.  Validate and update
  * our key material and status.
@@ -728,11 +828,9 @@ GSC_KX_handle_ephemeral_key (struct GSC_KeyExchangeInfo *kx,
   struct GNUNET_TIME_Absolute start_t;
   struct GNUNET_TIME_Absolute end_t;
   struct GNUNET_TIME_Absolute now;
-  struct GNUNET_PeerIdentity signer_id;
-  enum KxStateMachine sender_status;  
+  enum GNUNET_CORE_KxState sender_status;
   uint16_t size;
-  struct GNUNET_HashCode key_material;
-  
+
   size = ntohs (msg->size);
   if (sizeof (struct EphemeralKeyMessage) != size)
   {
@@ -740,19 +838,31 @@ GSC_KX_handle_ephemeral_key (struct GSC_KeyExchangeInfo *kx,
     return;
   }
   m = (const struct EphemeralKeyMessage *) msg;
-  GNUNET_STATISTICS_update (GSC_stats, gettext_noop ("# ephemeral keys received"),
+  end_t = GNUNET_TIME_absolute_ntoh (m->expiration_time);
+  if ( ( (GNUNET_CORE_KX_STATE_KEY_RECEIVED == kx->status) ||
+        (GNUNET_CORE_KX_STATE_UP == kx->status) ||
+        (GNUNET_CORE_KX_STATE_REKEY_SENT == kx->status) ) &&
+       (end_t.abs_value_us <= kx->foreign_key_expires.abs_value_us) )
+  {
+    GNUNET_STATISTICS_update (GSC_stats,
+                              gettext_noop ("# old ephemeral keys ignored"),
+                             1, GNUNET_NO);
+    return;
+  }
+  start_t = GNUNET_TIME_absolute_ntoh (m->creation_time);
+
+  GNUNET_STATISTICS_update (GSC_stats,
+                            gettext_noop ("# ephemeral keys received"),
                             1, GNUNET_NO);
 
   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
               "Core service receives `%s' request from `%4s'.\n", "EPHEMERAL_KEY",
               GNUNET_i2s (&kx->peer));
-  GNUNET_CRYPTO_hash (&m->origin_public_key,
-                     sizeof (struct GNUNET_CRYPTO_EccPublicKeyBinaryEncoded),
-                     &signer_id.hashPubKey);
   if (0 !=
-      memcmp (&signer_id, &kx->peer,
+      memcmp (&m->origin_identity,
+             &kx->peer.public_key,
               sizeof (struct GNUNET_PeerIdentity)))
-  {    
+  {
     GNUNET_break_op (0);
     return;
   }
@@ -760,70 +870,56 @@ GSC_KX_handle_ephemeral_key (struct GSC_KeyExchangeInfo *kx,
        sizeof (struct GNUNET_CRYPTO_EccSignaturePurpose) +
        sizeof (struct GNUNET_TIME_AbsoluteNBO) +
        sizeof (struct GNUNET_TIME_AbsoluteNBO) +
-       sizeof (struct GNUNET_CRYPTO_EccPublicKeyBinaryEncoded) +
-       sizeof (struct GNUNET_CRYPTO_EccPublicKeyBinaryEncoded)) ||
+       sizeof (struct GNUNET_CRYPTO_EddsaPublicKey) +
+       sizeof (struct GNUNET_CRYPTO_EddsaPublicKey)) ||
       (GNUNET_OK !=
-       GNUNET_CRYPTO_ecc_verify (GNUNET_SIGNATURE_PURPOSE_SET_ECC_KEY,
+       GNUNET_CRYPTO_eddsa_verify (GNUNET_SIGNATURE_PURPOSE_SET_ECC_KEY,
                                 &m->purpose,
-                                 &m->signature, &m->origin_public_key)))
+                                 &m->signature, &m->origin_identity.public_key)))
   {
     /* invalid signature */
     GNUNET_break_op (0);
     return;
   }
-  start_t = GNUNET_TIME_absolute_ntoh (m->creation_time);
-  end_t = GNUNET_TIME_absolute_ntoh (m->expiration_time);
   now = GNUNET_TIME_absolute_get ();
-  if ( (end_t.abs_value < GNUNET_TIME_absolute_subtract (now, REKEY_TOLERANCE).abs_value) ||
-       (start_t.abs_value > GNUNET_TIME_absolute_add (now, REKEY_TOLERANCE).abs_value) )
+  if ( (end_t.abs_value_us < GNUNET_TIME_absolute_subtract (now, REKEY_TOLERANCE).abs_value_us) ||
+       (start_t.abs_value_us > GNUNET_TIME_absolute_add (now, REKEY_TOLERANCE).abs_value_us) )
   {
     GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
-               _("Ephemeral key message rejected as its validity range does not match our system time (%llu not in [%llu,%llu]).\n"),
-               now.abs_value,
-               start_t.abs_value,
-               end_t.abs_value);
-    return;
-  }
-  if (GNUNET_OK !=
-      GNUNET_CRYPTO_ecc_ecdh (my_ephemeral_key,
-                             &m->ephemeral_key,                              
-                             &key_material))
-  {
-    GNUNET_break (0);
+               _("Ephemeral key message from peer `%s' rejected as its validity range does not match our system time (%llu not in [%llu,%llu]).\n"),
+               GNUNET_i2s (&kx->peer),
+               now.abs_value_us,
+               start_t.abs_value_us,
+               end_t.abs_value_us);
     return;
   }
+  kx->other_ephemeral_key = m->ephemeral_key;
+  kx->foreign_key_expires = end_t;
+  derive_session_keys (kx);
   GNUNET_STATISTICS_update (GSC_stats,
-                            gettext_noop ("# EPHEMERAL_KEY messages decrypted"), 1,
+                            gettext_noop ("# EPHEMERAL_KEY messages received"), 1,
                             GNUNET_NO);
-  derive_aes_key (&GSC_my_identity,
-                 &kx->peer,
-                 &key_material,
-                 &kx->encrypt_key);
-  derive_aes_key (&kx->peer,
-                 &GSC_my_identity,
-                 &key_material,
-                 &kx->decrypt_key);
-  /* fresh key, reset sequence numbers */
-  kx->last_sequence_number_received = 0;
-  kx->last_packets_bitmap = 0;
-  kx->foreign_key_expires = end_t;
-  setup_fresh_ping (kx);
 
   /* check if we still need to send the sender our key */
-  sender_status = (enum KxStateMachine) ntohl (m->sender_status);  
+  sender_status = (enum GNUNET_CORE_KxState) ntohl (m->sender_status);
   switch (sender_status)
   {
-  case KX_STATE_DOWN:
-    /* makes no sense, should be at least KX_STATE_KEY_SENT */
+  case GNUNET_CORE_KX_STATE_DOWN:
     GNUNET_break_op (0);
     break;
-  case KX_STATE_KEY_SENT:
-    send_key (kx);
+  case GNUNET_CORE_KX_STATE_KEY_SENT:
+    /* fine, need to send our key after updating our status, see below */
+    GSC_SESSIONS_reinit (&kx->peer);
+    break;
+  case GNUNET_CORE_KX_STATE_KEY_RECEIVED:
+    /* other peer already got our key, but typemap did go down */
+    GSC_SESSIONS_reinit (&kx->peer);
+    break;
+  case GNUNET_CORE_KX_STATE_UP:
+    /* other peer already got our key, typemap NOT down */
     break;
-  case KX_STATE_KEY_RECEIVED:
-  case KX_STATE_UP: 
-  case KX_STATE_REKEY_SENT:
-    /* other peer already got our key */
+  case GNUNET_CORE_KX_STATE_REKEY_SENT:
+    /* other peer already got our key, typemap NOT down */
     break;
   default:
     GNUNET_break (0);
@@ -832,24 +928,39 @@ GSC_KX_handle_ephemeral_key (struct GSC_KeyExchangeInfo *kx,
   /* check if we need to confirm everything is fine via PING + PONG */
   switch (kx->status)
   {
-  case KX_STATE_DOWN:
-    kx->status = KX_STATE_KEY_RECEIVED;
+  case GNUNET_CORE_KX_STATE_DOWN:
+    GNUNET_assert (NULL == kx->keep_alive_task);
+    kx->status = GNUNET_CORE_KX_STATE_KEY_RECEIVED;
+    monitor_notify_all (kx);
+    if (GNUNET_CORE_KX_STATE_KEY_SENT == sender_status)
+      send_key (kx);
     send_ping (kx);
     break;
-  case KX_STATE_KEY_SENT:
-    kx->status = KX_STATE_KEY_RECEIVED;
+  case GNUNET_CORE_KX_STATE_KEY_SENT:
+    GNUNET_assert (NULL == kx->keep_alive_task);
+    kx->status = GNUNET_CORE_KX_STATE_KEY_RECEIVED;
+    monitor_notify_all (kx);
+    if (GNUNET_CORE_KX_STATE_KEY_SENT == sender_status)
+      send_key (kx);
     send_ping (kx);
     break;
-  case KX_STATE_KEY_RECEIVED:
+  case GNUNET_CORE_KX_STATE_KEY_RECEIVED:
+    GNUNET_assert (NULL == kx->keep_alive_task);
+    if (GNUNET_CORE_KX_STATE_KEY_SENT == sender_status)
+      send_key (kx);
     send_ping (kx);
     break;
-  case KX_STATE_UP: 
-    kx->status = KX_STATE_KEY_RECEIVED;
+  case GNUNET_CORE_KX_STATE_UP:
+    kx->status = GNUNET_CORE_KX_STATE_REKEY_SENT;
+    monitor_notify_all (kx);
+    if (GNUNET_CORE_KX_STATE_KEY_SENT == sender_status)
+      send_key (kx);
     /* we got a new key, need to reconfirm! */
     send_ping (kx);
     break;
-  case KX_STATE_REKEY_SENT:
-    kx->status = KX_STATE_KEY_RECEIVED;
+  case GNUNET_CORE_KX_STATE_REKEY_SENT:
+    if (GNUNET_CORE_KX_STATE_KEY_SENT == sender_status)
+      send_key (kx);
     /* we got a new key, need to reconfirm! */
     send_ping (kx);
     break;
@@ -875,7 +986,7 @@ GSC_KX_handle_ping (struct GSC_KeyExchangeInfo *kx,
   struct PingMessage t;
   struct PongMessage tx;
   struct PongMessage tp;
-  struct GNUNET_CRYPTO_AesInitializationVector iv;
+  struct GNUNET_CRYPTO_SymmetricInitializationVector iv;
   uint16_t msize;
 
   msize = ntohs (msg->size);
@@ -887,9 +998,9 @@ GSC_KX_handle_ping (struct GSC_KeyExchangeInfo *kx,
   GNUNET_STATISTICS_update (GSC_stats,
                             gettext_noop ("# PING messages received"), 1,
                             GNUNET_NO);
-  if ( (kx->status != KX_STATE_KEY_RECEIVED) && 
-       (kx->status != KX_STATE_UP) &&
-       (kx->status != KX_STATE_REKEY_SENT))
+  if ( (kx->status != GNUNET_CORE_KX_STATE_KEY_RECEIVED) &&
+       (kx->status != GNUNET_CORE_KX_STATE_UP) &&
+       (kx->status != GNUNET_CORE_KX_STATE_REKEY_SENT))
   {
     /* ignore */
     GNUNET_STATISTICS_update (GSC_stats,
@@ -931,15 +1042,15 @@ GSC_KX_handle_ping (struct GSC_KeyExchangeInfo *kx,
   tx.target = t.target;
   tp.header.type = htons (GNUNET_MESSAGE_TYPE_CORE_PONG);
   tp.header.size = htons (sizeof (struct PongMessage));
-  tp.iv_seed =
-      GNUNET_CRYPTO_random_u32 (GNUNET_CRYPTO_QUALITY_NONCE, UINT32_MAX);
+  tp.iv_seed = calculate_seed (kx);
   derive_pong_iv (&iv, &kx->encrypt_key, tp.iv_seed, t.challenge, &kx->peer);
   do_encrypt (kx, &iv, &tx.challenge, &tp.challenge,
               sizeof (struct PongMessage) - ((void *) &tp.challenge -
                                              (void *) &tp));
   GNUNET_STATISTICS_update (GSC_stats, gettext_noop ("# PONG messages created"),
                             1, GNUNET_NO);
-  GSC_NEIGHBOURS_transmit (&kx->peer, &tp.header,
+  GSC_NEIGHBOURS_transmit (&kx->peer,
+                           &tp.header,
                            GNUNET_TIME_UNIT_FOREVER_REL /* FIXME: timeout */ );
 }
 
@@ -958,15 +1069,16 @@ send_keep_alive (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
   struct GNUNET_TIME_Relative retry;
   struct GNUNET_TIME_Relative left;
 
-  kx->keep_alive_task = GNUNET_SCHEDULER_NO_TASK;
+  kx->keep_alive_task = NULL;
   left = GNUNET_TIME_absolute_get_remaining (kx->timeout);
-  if (0 == left.rel_value)
+  if (0 == left.rel_value_us)
   {
     GNUNET_STATISTICS_update (GSC_stats,
                               gettext_noop ("# sessions terminated by timeout"),
                               1, GNUNET_NO);
     GSC_SESSIONS_end (&kx->peer);
-    kx->status = KX_STATE_KEY_SENT;
+    kx->status = GNUNET_CORE_KX_STATE_KEY_SENT;
+    monitor_notify_all (kx);
     send_key (kx);
     return;
   }
@@ -976,7 +1088,8 @@ send_keep_alive (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
                             gettext_noop ("# keepalive messages sent"), 1,
                             GNUNET_NO);
   setup_fresh_ping (kx);
-  GSC_NEIGHBOURS_transmit (&kx->peer, &kx->ping.header,
+  GSC_NEIGHBOURS_transmit (&kx->peer,
+                           &kx->ping.header,
                            kx->set_key_retry_frequency);
   retry =
       GNUNET_TIME_relative_max (GNUNET_TIME_relative_divide (left, 2),
@@ -996,10 +1109,20 @@ send_keep_alive (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
 static void
 update_timeout (struct GSC_KeyExchangeInfo *kx)
 {
+  struct GNUNET_TIME_Relative delta;
+
   kx->timeout =
       GNUNET_TIME_relative_to_absolute
       (GNUNET_CONSTANTS_IDLE_CONNECTION_TIMEOUT);
-  if (kx->keep_alive_task != GNUNET_SCHEDULER_NO_TASK)
+  delta = GNUNET_TIME_absolute_get_difference (kx->last_notify_timeout,
+                                               kx->timeout);
+  if (delta.rel_value_us > 5LL * 1000LL * 1000LL)
+  {
+    /* we only notify monitors about timeout changes if those
+       are bigger than the threshold (5s) */
+    monitor_notify_all (kx);
+  }
+  if (kx->keep_alive_task != NULL)
     GNUNET_SCHEDULER_cancel (kx->keep_alive_task);
   kx->keep_alive_task =
       GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_relative_divide
@@ -1020,7 +1143,7 @@ GSC_KX_handle_pong (struct GSC_KeyExchangeInfo *kx,
 {
   const struct PongMessage *m;
   struct PongMessage t;
-  struct GNUNET_CRYPTO_AesInitializationVector iv;
+  struct GNUNET_CRYPTO_SymmetricInitializationVector iv;
   uint16_t msize;
 
   msize = ntohs (msg->size);
@@ -1034,21 +1157,21 @@ GSC_KX_handle_pong (struct GSC_KeyExchangeInfo *kx,
                             GNUNET_NO);
   switch (kx->status)
   {
-  case KX_STATE_DOWN:
+  case GNUNET_CORE_KX_STATE_DOWN:
     GNUNET_STATISTICS_update (GSC_stats,
                              gettext_noop ("# PONG messages dropped (connection down)"), 1,
                              GNUNET_NO);
     return;
-  case KX_STATE_KEY_SENT:
+  case GNUNET_CORE_KX_STATE_KEY_SENT:
     GNUNET_STATISTICS_update (GSC_stats,
                              gettext_noop ("# PONG messages dropped (out of order)"), 1,
                              GNUNET_NO);
     return;
-  case KX_STATE_KEY_RECEIVED:
+  case GNUNET_CORE_KX_STATE_KEY_RECEIVED:
     break;
-  case KX_STATE_UP:
+  case GNUNET_CORE_KX_STATE_UP:
     break;
-  case KX_STATE_REKEY_SENT:
+  case GNUNET_CORE_KX_STATE_REKEY_SENT:
     break;
   default:
     GNUNET_break (0);
@@ -1086,45 +1209,48 @@ GSC_KX_handle_pong (struct GSC_KeyExchangeInfo *kx,
                 "PONG", GNUNET_i2s (&t.target), (unsigned int) t.challenge);
     return;
   }
-  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Received PONG from `%s'\n",
+  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+              "Received PONG from `%s'\n",
               GNUNET_i2s (&kx->peer));
   /* no need to resend key any longer */
-  if (GNUNET_SCHEDULER_NO_TASK != kx->retry_set_key_task)
+  if (NULL != kx->retry_set_key_task)
   {
     GNUNET_SCHEDULER_cancel (kx->retry_set_key_task);
-    kx->retry_set_key_task = GNUNET_SCHEDULER_NO_TASK;
-  }  
+    kx->retry_set_key_task = NULL;
+  }
   switch (kx->status)
   {
-  case KX_STATE_DOWN:
+  case GNUNET_CORE_KX_STATE_DOWN:
     GNUNET_assert (0);           /* should be impossible */
     return;
-  case KX_STATE_KEY_SENT:
+  case GNUNET_CORE_KX_STATE_KEY_SENT:
     GNUNET_assert (0);           /* should be impossible */
     return;
-  case KX_STATE_KEY_RECEIVED:
+  case GNUNET_CORE_KX_STATE_KEY_RECEIVED:
     GNUNET_STATISTICS_update (GSC_stats,
                               gettext_noop
                               ("# session keys confirmed via PONG"), 1,
                               GNUNET_NO);
-    kx->status = KX_STATE_UP;
+    kx->status = GNUNET_CORE_KX_STATE_UP;
+    monitor_notify_all (kx);
     GSC_SESSIONS_create (&kx->peer, kx);
-    GNUNET_assert (GNUNET_SCHEDULER_NO_TASK == kx->keep_alive_task);
+    GNUNET_assert (NULL == kx->keep_alive_task);
     update_timeout (kx);
     break;
-  case KX_STATE_UP:
+  case GNUNET_CORE_KX_STATE_UP:
     GNUNET_STATISTICS_update (GSC_stats,
                               gettext_noop
                               ("# timeouts prevented via PONG"), 1,
                               GNUNET_NO);
     update_timeout (kx);
     break;
-  case KX_STATE_REKEY_SENT:
+  case GNUNET_CORE_KX_STATE_REKEY_SENT:
     GNUNET_STATISTICS_update (GSC_stats,
                               gettext_noop
                               ("# rekey operations confirmed via PONG"), 1,
                               GNUNET_NO);
-    kx->status = KX_STATE_UP;
+    kx->status = GNUNET_CORE_KX_STATE_UP;
+    monitor_notify_all (kx);
     update_timeout (kx);
     break;
   default:
@@ -1142,18 +1268,20 @@ GSC_KX_handle_pong (struct GSC_KeyExchangeInfo *kx,
 static void
 send_key (struct GSC_KeyExchangeInfo *kx)
 {
-  if (GNUNET_SCHEDULER_NO_TASK != kx->retry_set_key_task)
+  GNUNET_assert (GNUNET_CORE_KX_STATE_DOWN != kx->status);
+  if (NULL != kx->retry_set_key_task)
   {
      GNUNET_SCHEDULER_cancel (kx->retry_set_key_task);
-     kx->retry_set_key_task = GNUNET_SCHEDULER_NO_TASK;
+     kx->retry_set_key_task = NULL;
   }
   /* always update sender status in SET KEY message */
-  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, 
+  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "Sending key to `%s' (my status: %d)\n",
               GNUNET_i2s (&kx->peer),
              kx->status);
-  current_ekm.sender_status = htonl ((int32_t) (kx->status));  
-  GSC_NEIGHBOURS_transmit (&kx->peer, &current_ekm.header,
+  current_ekm.sender_status = htonl ((int32_t) (kx->status));
+  GSC_NEIGHBOURS_transmit (&kx->peer,
+                           &current_ekm.header,
                            kx->set_key_retry_frequency);
   kx->retry_set_key_task =
       GNUNET_SCHEDULER_add_delayed (kx->set_key_retry_frequency,
@@ -1166,25 +1294,24 @@ send_key (struct GSC_KeyExchangeInfo *kx)
  *
  * @param kx key exchange context
  * @param payload payload of the message
- * @param payload_size number of bytes in 'payload'
+ * @param payload_size number of bytes in @a payload
  */
 void
 GSC_KX_encrypt_and_transmit (struct GSC_KeyExchangeInfo *kx,
-                             const void *payload, size_t payload_size)
+                             const void *payload,
+                             size_t payload_size)
 {
   size_t used = payload_size + sizeof (struct EncryptedMessage);
   char pbuf[used];              /* plaintext */
   char cbuf[used];              /* ciphertext */
   struct EncryptedMessage *em;  /* encrypted message */
   struct EncryptedMessage *ph;  /* plaintext header */
-  struct GNUNET_CRYPTO_AesInitializationVector iv;
+  struct GNUNET_CRYPTO_SymmetricInitializationVector iv;
   struct GNUNET_CRYPTO_AuthKey auth_key;
 
   ph = (struct EncryptedMessage *) pbuf;
-  ph->iv_seed =
-      htonl (GNUNET_CRYPTO_random_u32
-             (GNUNET_CRYPTO_QUALITY_NONCE, UINT32_MAX));
   ph->sequence_number = htonl (++kx->last_sequence_number_sent);
+  ph->iv_seed = calculate_seed (kx);
   ph->reserved = 0;
   ph->timestamp = GNUNET_TIME_absolute_hton (GNUNET_TIME_absolute_get ());
   memcpy (&ph[1], payload, payload_size);
@@ -1200,36 +1327,32 @@ GSC_KX_encrypt_and_transmit (struct GSC_KeyExchangeInfo *kx,
                              used - ENCRYPTED_HEADER_SIZE));
   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Encrypted %u bytes for %s\n",
               used - ENCRYPTED_HEADER_SIZE, GNUNET_i2s (&kx->peer));
-  derive_auth_key (&auth_key, 
-                  &kx->encrypt_key, 
+  derive_auth_key (&auth_key,
+                  &kx->encrypt_key,
                   ph->iv_seed);
   GNUNET_CRYPTO_hmac (&auth_key, &em->sequence_number,
                       used - ENCRYPTED_HEADER_SIZE, &em->hmac);
-  GSC_NEIGHBOURS_transmit (&kx->peer, &em->header,
+  GSC_NEIGHBOURS_transmit (&kx->peer,
+                           &em->header,
                            GNUNET_TIME_UNIT_FOREVER_REL);
 }
 
 
 /**
- * Closure for 'deliver_message'
+ * Closure for #deliver_message()
  */
 struct DeliverMessageContext
 {
 
   /**
-   * Performance information for the connection.
+   * Key exchange context.
    */
-  const struct GNUNET_ATS_Information *atsi;
+  struct GSC_KeyExchangeInfo *kx;
 
   /**
    * Sender of the message.
    */
   const struct GNUNET_PeerIdentity *peer;
-
-  /**
-   * Number of entries in 'atsi' array.
-   */
-  uint32_t atsi_count;
 };
 
 
@@ -1239,21 +1362,17 @@ struct DeliverMessageContext
  *
  * @param kx key exchange context for encrypting the message
  * @param msg encrypted message
- * @param atsi performance data
- * @param atsi_count number of entries in ats (excluding 0-termination)
  */
 void
 GSC_KX_handle_encrypted_message (struct GSC_KeyExchangeInfo *kx,
-                                 const struct GNUNET_MessageHeader *msg,
-                                 const struct GNUNET_ATS_Information *atsi,
-                                 uint32_t atsi_count)
+                                 const struct GNUNET_MessageHeader *msg)
 {
   const struct EncryptedMessage *m;
   struct EncryptedMessage *pt;  /* plaintext */
   struct GNUNET_HashCode ph;
   uint32_t snum;
   struct GNUNET_TIME_Absolute t;
-  struct GNUNET_CRYPTO_AesInitializationVector iv;
+  struct GNUNET_CRYPTO_SymmetricInitializationVector iv;
   struct GNUNET_CRYPTO_AuthKey auth_key;
   struct DeliverMessageContext dmc;
   uint16_t size = ntohs (msg->size);
@@ -1266,7 +1385,7 @@ GSC_KX_handle_encrypted_message (struct GSC_KeyExchangeInfo *kx,
     return;
   }
   m = (const struct EncryptedMessage *) msg;
-  if (kx->status != KX_STATE_UP)
+  if (GNUNET_CORE_KX_STATE_UP != kx->status)
   {
     GNUNET_STATISTICS_update (GSC_stats,
                               gettext_noop
@@ -1274,13 +1393,22 @@ GSC_KX_handle_encrypted_message (struct GSC_KeyExchangeInfo *kx,
                               1, GNUNET_NO);
     return;
   }
-  if (0 == GNUNET_TIME_absolute_get_remaining (kx->foreign_key_expires).rel_value)
+  if (0 == GNUNET_TIME_absolute_get_remaining (kx->foreign_key_expires).rel_value_us)
   {
-    kx->status = KX_STATE_KEY_SENT;
+    GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
+               _("Session to peer `%s' went down due to key expiration (should not happen)\n"),
+               GNUNET_i2s (&kx->peer));
     GNUNET_STATISTICS_update (GSC_stats,
-                              gettext_noop
-                              ("# DATA message dropped (session key expired)"),
+                              gettext_noop ("# sessions terminated by key expiration"),
                               1, GNUNET_NO);
+    GSC_SESSIONS_end (&kx->peer);
+    if (NULL != kx->keep_alive_task)
+    {
+      GNUNET_SCHEDULER_cancel (kx->keep_alive_task);
+      kx->keep_alive_task = NULL;
+    }
+    kx->status = GNUNET_CORE_KX_STATE_KEY_SENT;
+    monitor_notify_all (kx);
     send_key (kx);
     return;
   }
@@ -1292,8 +1420,8 @@ GSC_KX_handle_encrypted_message (struct GSC_KeyExchangeInfo *kx,
   if (0 != memcmp (&ph, &m->hmac, sizeof (struct GNUNET_HashCode)))
   {
     /* checksum failed */
-    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, 
-               "Failed checksum validation for a message from `%s'\n", 
+    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+               "Failed checksum validation for a message from `%s'\n",
                GNUNET_i2s (&kx->peer));
     return;
   }
@@ -1303,8 +1431,10 @@ GSC_KX_handle_encrypted_message (struct GSC_KeyExchangeInfo *kx,
       do_decrypt (kx, &iv, &m->sequence_number, &buf[ENCRYPTED_HEADER_SIZE],
                   size - ENCRYPTED_HEADER_SIZE))
     return;
-  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Decrypted %u bytes from %s\n",
-              size - ENCRYPTED_HEADER_SIZE, GNUNET_i2s (&kx->peer));
+  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+              "Decrypted %u bytes from %s\n",
+              size - ENCRYPTED_HEADER_SIZE,
+              GNUNET_i2s (&kx->peer));
   pt = (struct EncryptedMessage *) buf;
 
   /* validate sequence number */
@@ -1360,12 +1490,13 @@ GSC_KX_handle_encrypted_message (struct GSC_KeyExchangeInfo *kx,
 
   /* check timestamp */
   t = GNUNET_TIME_absolute_ntoh (pt->timestamp);
-  if (GNUNET_TIME_absolute_get_duration (t).rel_value >
-      MAX_MESSAGE_AGE.rel_value)
+  if (GNUNET_TIME_absolute_get_duration (t).rel_value_us >
+      MAX_MESSAGE_AGE.rel_value_us)
   {
     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
                 "Message received far too old (%s). Content ignored.\n",
-                GNUNET_STRINGS_relative_time_to_string (GNUNET_TIME_absolute_get_duration (t), GNUNET_YES));
+                GNUNET_STRINGS_relative_time_to_string (GNUNET_TIME_absolute_get_duration (t),
+                                                        GNUNET_YES));
     GNUNET_STATISTICS_update (GSC_stats,
                               gettext_noop
                               ("# bytes dropped (ancient message)"), size,
@@ -1377,15 +1508,16 @@ GSC_KX_handle_encrypted_message (struct GSC_KeyExchangeInfo *kx,
   update_timeout (kx);
   GNUNET_STATISTICS_update (GSC_stats,
                             gettext_noop ("# bytes of payload decrypted"),
-                            size - sizeof (struct EncryptedMessage), GNUNET_NO);
-  dmc.atsi = atsi;
-  dmc.atsi_count = atsi_count;
+                            size - sizeof (struct EncryptedMessage),
+                            GNUNET_NO);
+  dmc.kx = kx;
   dmc.peer = &kx->peer;
   if (GNUNET_OK !=
       GNUNET_SERVER_mst_receive (mst, &dmc,
                                  &buf[sizeof (struct EncryptedMessage)],
                                  size - sizeof (struct EncryptedMessage),
-                                 GNUNET_YES, GNUNET_NO))
+                                 GNUNET_YES,
+                                 GNUNET_NO))
     GNUNET_break_op (0);
 }
 
@@ -1400,21 +1532,34 @@ GSC_KX_handle_encrypted_message (struct GSC_KeyExchangeInfo *kx,
  * @param m the message
  */
 static int
-deliver_message (void *cls, void *client, const struct GNUNET_MessageHeader *m)
+deliver_message (void *cls,
+                 void *client,
+                 const struct GNUNET_MessageHeader *m)
 {
   struct DeliverMessageContext *dmc = client;
 
+  if (GNUNET_CORE_KX_STATE_UP != dmc->kx->status)
+  {
+    GNUNET_STATISTICS_update (GSC_stats,
+                              gettext_noop
+                              ("# PAYLOAD dropped (out of order)"),
+                              1, GNUNET_NO);
+    return GNUNET_OK;
+  }
   switch (ntohs (m->type))
   {
   case GNUNET_MESSAGE_TYPE_CORE_BINARY_TYPE_MAP:
   case GNUNET_MESSAGE_TYPE_CORE_COMPRESSED_TYPE_MAP:
     GSC_SESSIONS_set_typemap (dmc->peer, m);
     return GNUNET_OK;
+  case GNUNET_MESSAGE_TYPE_CORE_CONFIRM_TYPE_MAP:
+    GSC_SESSIONS_confirm_typemap (dmc->peer, m);
+    return GNUNET_OK;
   default:
-    GSC_CLIENTS_deliver_message (dmc->peer, dmc->atsi, dmc->atsi_count, m,
+    GSC_CLIENTS_deliver_message (dmc->peer, m,
                                  ntohs (m->size),
                                  GNUNET_CORE_OPTION_SEND_FULL_INBOUND);
-    GSC_CLIENTS_deliver_message (dmc->peer, dmc->atsi, dmc->atsi_count, m,
+    GSC_CLIENTS_deliver_message (dmc->peer, m,
                                  sizeof (struct GNUNET_MessageHeader),
                                  GNUNET_CORE_OPTION_SEND_HDR_INBOUND);
   }
@@ -1436,16 +1581,26 @@ sign_ephemeral_key ()
   current_ekm.purpose.size = htonl (sizeof (struct GNUNET_CRYPTO_EccSignaturePurpose) +
                                    sizeof (struct GNUNET_TIME_AbsoluteNBO) +
                                    sizeof (struct GNUNET_TIME_AbsoluteNBO) +
-                                   sizeof (struct GNUNET_CRYPTO_EccPublicKeyBinaryEncoded) +
-                                   sizeof (struct GNUNET_CRYPTO_EccPublicKeyBinaryEncoded));
+                                   sizeof (struct GNUNET_CRYPTO_EcdhePublicKey) +
+                                   sizeof (struct GNUNET_PeerIdentity));
   current_ekm.creation_time = GNUNET_TIME_absolute_hton (GNUNET_TIME_absolute_get ());
-  current_ekm.expiration_time = GNUNET_TIME_absolute_hton (GNUNET_TIME_relative_to_absolute (GNUNET_TIME_relative_add (REKEY_FREQUENCY,
-                                                                                                                      REKEY_TOLERANCE)));
-  GNUNET_CRYPTO_ecc_key_get_public (my_ephemeral_key,
-                                   &current_ekm.ephemeral_key);
-  current_ekm.origin_public_key = my_public_key;
+  if (GNUNET_YES ==
+      GNUNET_CONFIGURATION_get_value_yesno (GSC_cfg,
+                                           "core",
+                                           "USE_EPHEMERAL_KEYS"))
+  {
+    current_ekm.expiration_time = GNUNET_TIME_absolute_hton (GNUNET_TIME_relative_to_absolute (GNUNET_TIME_relative_add (REKEY_FREQUENCY,
+                                                                                                                        REKEY_TOLERANCE)));
+  }
+  else
+  {
+    current_ekm.expiration_time = GNUNET_TIME_absolute_hton (GNUNET_TIME_UNIT_FOREVER_ABS);
+  }
+  GNUNET_CRYPTO_ecdhe_key_get_public (my_ephemeral_key,
+                                      &current_ekm.ephemeral_key);
+  current_ekm.origin_identity = GSC_my_identity;
   GNUNET_assert (GNUNET_OK ==
-                GNUNET_CRYPTO_ecc_sign (my_private_key,
+                GNUNET_CRYPTO_eddsa_sign (my_private_key,
                                         &current_ekm.purpose,
                                         &current_ekm.signature));
 }
@@ -1467,13 +1622,24 @@ do_rekey (void *cls,
                                             &do_rekey,
                                             NULL);
   if (NULL != my_ephemeral_key)
-    GNUNET_CRYPTO_ecc_key_free (my_ephemeral_key);
-  my_ephemeral_key = GNUNET_CRYPTO_ecc_key_create ();
+    GNUNET_free (my_ephemeral_key);
+  my_ephemeral_key = GNUNET_CRYPTO_ecdhe_key_create ();
   GNUNET_assert (NULL != my_ephemeral_key);
   sign_ephemeral_key ();
   for (pos = kx_head; NULL != pos; pos = pos->next)
   {
-    pos->status = KX_STATE_REKEY_SENT;
+    if (GNUNET_CORE_KX_STATE_UP == pos->status)
+    {
+      pos->status = GNUNET_CORE_KX_STATE_REKEY_SENT;
+      monitor_notify_all (pos);
+      derive_session_keys (pos);
+    }
+    if (GNUNET_CORE_KX_STATE_DOWN == pos->status)
+    {
+      pos->status = GNUNET_CORE_KX_STATE_KEY_SENT;
+      monitor_notify_all (pos);
+    }
+    monitor_notify_all (pos);
     send_key (pos);
   }
 }
@@ -1483,29 +1649,31 @@ do_rekey (void *cls,
  * Initialize KX subsystem.
  *
  * @param pk private key to use for the peer
- * @return GNUNET_OK on success, GNUNET_SYSERR on failure
+ * @param server the server of the CORE service
+ * @return #GNUNET_OK on success, #GNUNET_SYSERR on failure
  */
 int
-GSC_KX_init (struct GNUNET_CRYPTO_EccPrivateKey *pk)
+GSC_KX_init (struct GNUNET_CRYPTO_EddsaPrivateKey *pk,
+             struct GNUNET_SERVER_Handle *server)
 {
-  GNUNET_assert (NULL != pk);
+  nc = GNUNET_SERVER_notification_context_create (server,
+                                                  1);
   my_private_key = pk;
-  GNUNET_CRYPTO_ecc_key_get_public (my_private_key, &my_public_key);
-  GNUNET_CRYPTO_hash (&my_public_key, sizeof (my_public_key),
-                      &GSC_my_identity.hashPubKey);
-  my_ephemeral_key = GNUNET_CRYPTO_ecc_key_create ();
+  GNUNET_CRYPTO_eddsa_key_get_public (my_private_key,
+                                                 &GSC_my_identity.public_key);
+  my_ephemeral_key = GNUNET_CRYPTO_ecdhe_key_create ();
   if (NULL == my_ephemeral_key)
   {
     GNUNET_break (0);
-    GNUNET_CRYPTO_ecc_key_free (my_private_key);
+    GNUNET_free (my_private_key);
     my_private_key = NULL;
     return GNUNET_SYSERR;
   }
   sign_ephemeral_key ();
-  mst = GNUNET_SERVER_mst_create (&deliver_message, NULL);
   rekey_task = GNUNET_SCHEDULER_add_delayed (REKEY_FREQUENCY,
-                                            &do_rekey,
-                                            NULL);
+                                             &do_rekey,
+                                             NULL);
+  mst = GNUNET_SERVER_mst_create (&deliver_message, NULL);
   return GNUNET_OK;
 }
 
@@ -1516,26 +1684,67 @@ GSC_KX_init (struct GNUNET_CRYPTO_EccPrivateKey *pk)
 void
 GSC_KX_done ()
 {
-  if (GNUNET_SCHEDULER_NO_TASK != rekey_task)
+  if (NULL != rekey_task)
   {
     GNUNET_SCHEDULER_cancel (rekey_task);
-    rekey_task = GNUNET_SCHEDULER_NO_TASK;
-  }
-  if (NULL != my_private_key)
-  {
-    GNUNET_CRYPTO_ecc_key_free (my_private_key);
-    my_private_key = NULL;
+    rekey_task = NULL;
   }
   if (NULL != my_ephemeral_key)
   {
-    GNUNET_CRYPTO_ecc_key_free (my_ephemeral_key);
+    GNUNET_free (my_ephemeral_key);
     my_ephemeral_key = NULL;
   }
+  if (NULL != my_private_key)
+  {
+    GNUNET_free (my_private_key);
+    my_private_key = NULL;
+  }
   if (NULL != mst)
   {
     GNUNET_SERVER_mst_destroy (mst);
     mst = NULL;
   }
+  if (NULL != nc)
+  {
+    GNUNET_SERVER_notification_context_destroy (nc);
+    nc = NULL;
+  }
+}
+
+
+/**
+ * Handle #GNUNET_MESSAGE_TYPE_CORE_MONITOR_PEERS request.  For this
+ * request type, the client does not have to have transmitted an INIT
+ * request.  All current peers are returned, regardless of which
+ * message types they accept.
+ *
+ * @param cls unused
+ * @param client client sending the iteration request
+ * @param message iteration request message
+ */
+void
+GSC_KX_handle_client_monitor_peers (void *cls,
+                                    struct GNUNET_SERVER_Client *client,
+                                    const struct GNUNET_MessageHeader *message)
+{
+  struct MonitorNotifyMessage done_msg;
+  struct GSC_KeyExchangeInfo *kx;
+
+  GNUNET_SERVER_receive_done (client, GNUNET_OK);
+  GNUNET_SERVER_notification_context_add (nc,
+                                          client);
+  for (kx = kx_head; NULL != kx; kx = kx->next)
+    monitor_notify (client, kx);
+  done_msg.header.size = htons (sizeof (struct MonitorNotifyMessage));
+  done_msg.header.type = htons (GNUNET_MESSAGE_TYPE_CORE_MONITOR_NOTIFY);
+  done_msg.state = htonl ((uint32_t) GNUNET_CORE_KX_ITERATION_FINISHED);
+  memset (&done_msg.peer, 0, sizeof (struct GNUNET_PeerIdentity));
+  done_msg.timeout = GNUNET_TIME_absolute_hton (GNUNET_TIME_UNIT_FOREVER_ABS);
+  GNUNET_SERVER_notification_context_unicast (nc,
+                                              client,
+                                              &done_msg.header,
+                                              GNUNET_NO);
 }
 
+
 /* end of gnunet-service-core_kx.c */