trying to make KX logic slightly more readable
[oweals/gnunet.git] / src / cadet / cadet_protocol.h
index 2a0de2a8f88336e4588bf4b241b30acd8e69a4d1..e2d6f9d0bfdcae8d0a3447ee1e6dd5bf5fd6a5fd 100644 (file)
@@ -87,7 +87,7 @@ struct GNUNET_CADET_ConnectionCreateMessage
 /**
  * Message for ack'ing a connection
  */
-struct GNUNET_CADET_ConnectionCreateMessageAckMessage
+struct GNUNET_CADET_ConnectionCreateAckMessage
 {
   /**
    * Type: #GNUNET_MESSAGE_TYPE_CADET_CONNECTION_CREATE_ACK
@@ -113,7 +113,7 @@ struct GNUNET_CADET_ConnectionCreateMessageAckMessage
 struct GNUNET_CADET_ConnectionBrokenMessage
 {
   /**
-   * Type: #GNUNET_MESSAGE_TYPE_CADET_CONNECTION_BROKEN
+   * Type: #GNUNET_MESSAGE_TYPE_CADET_CONNECTION_BROKEN.
    */
   struct GNUNET_MessageHeader header;
 
@@ -161,11 +161,15 @@ struct GNUNET_CADET_ConnectionDestroyMessage
 };
 
 
+/******************************************************************************/
+/*******************************   TUNNEL   ***********************************/
+/******************************************************************************/
+
 /**
  * Unique identifier (counter) for an encrypted message in a channel.
- * Used to match #GNUNET_MESSAGE_TYPE_CADET_ENCRYPTED_HOP_BY_HOP_ACK
- * and  #GNUNET_MESSAGE_TYPE_CADET_CONNECTION_HOP_BY_HOP_POLL messages
- * against the respective  #GNUNET_MESSAGE_TYPE_CONNECTION_ENCRYPTED
+ * Used to match #GNUNET_MESSAGE_TYPE_CADET_CONNECTION_HOP_BY_HOP_ENCRYPTED_ACK
+ * and  #GNUNET_MESSAGE_TYPE_CADET_TUNNEL_ENCRYPTED_POLL messages
+ * against the respective  #GNUNET_MESSAGE_TYPE_CADET_TUNNEL_ENCRYPTED
  * messages.
  */
 struct CadetEncryptedMessageIdentifier
@@ -179,123 +183,129 @@ struct CadetEncryptedMessageIdentifier
 
 
 /**
- * Message to acknowledge cadet encrypted traffic.
+ * Flags to be used in GNUNET_CADET_KX.
  */
-struct GNUNET_CADET_ConnectionEncryptedAckMessage
-{
-  /**
-   * Type: #GNUNET_MESSAGE_TYPE_CADET_ENCRYPTED_HOP_BY_HOP_ACK
-   */
-  struct GNUNET_MessageHeader header;
+enum GNUNET_CADET_KX_Flags {
 
   /**
-   * Maximum packet ID authorized.
+   * Should the peer reply with its KX details?
    */
-  struct CadetEncryptedMessageIdentifier cemi;
+  GNUNET_CADET_KX_FLAG_NONE = 0,
 
   /**
-   * ID of the connection.
+   * The peer should reply with its KX details?
    */
-  struct GNUNET_CADET_ConnectionTunnelIdentifier cid;
+  GNUNET_CADET_KX_FLAG_FORCE_REPLY = 1
 };
 
 
 /**
- * Message to query a peer about its Flow Control status regarding a tunnel.
+ * Message for a Key eXchange for a tunnel.
  */
-struct GNUNET_CADET_ConnectionHopByHopPollMessage
+struct GNUNET_CADET_TunnelKeyExchangeMessage
 {
   /**
-   * Type: #GNUNET_MESSAGE_TYPE_CADET_CONNECTION_HOP_BY_HOP_POLL
+   * Type: #GNUNET_MESSAGE_TYPE_CADET_TUNNEL_KX or
+   * #GNUNET_MESSAGE_TYPE_CADET_TUNNEL_KX_AUTH as part
+   * of `struct GNUNET_CADET_TunnelKeyExchangeAuthMessage`.
    */
   struct GNUNET_MessageHeader header;
 
   /**
-   * Last packet sent.
+   * Flags for the key exchange in NBO, based on
+   * `enum GNUNET_CADET_KX_Flags`.
    */
-  struct CadetEncryptedMessageIdentifier cemi;
+  uint32_t flags GNUNET_PACKED;
 
   /**
    * ID of the connection.
    */
   struct GNUNET_CADET_ConnectionTunnelIdentifier cid;
 
-};
+  /**
+   * Sender's ephemeral public ECC key encoded in a
+   * format suitable for network transmission, as created
+   * using 'gcry_sexp_sprint'.
+   */
+  struct GNUNET_CRYPTO_EcdhePublicKey ephemeral_key;
 
+  /**
+   * Sender's next ephemeral public ECC key encoded in a
+   * format suitable for network transmission, as created
+   * using 'gcry_sexp_sprint'.
+   */
+  struct GNUNET_CRYPTO_EcdhePublicKey ratchet_key;
 
+};
 
-/******************************************************************************/
-/*******************************   TUNNEL   ***********************************/
-/******************************************************************************/
 
 /**
- * Flags to be used in GNUNET_CADET_KX.
+ * Message for a Key eXchange for a tunnel, with authentication.
+ * Used as a response to the initial KX as well as for rekeying.
  */
-enum GNUNET_CADET_KX_Flags {
+struct GNUNET_CADET_TunnelKeyExchangeAuthMessage
+{
 
   /**
-   * Should the peer reply with its KX details?
+   * Message header with key material.
    */
-  GNUNET_CADET_KX_FLAG_NONE = 0,
+  struct GNUNET_CADET_TunnelKeyExchangeMessage kx;
 
   /**
-   * The peer should reply with its KX details?
+   * KDF-proof that sender could compute the 3-DH, used in lieu of a
+   * signature or payload data.
    */
-  GNUNET_CADET_KX_FLAG_FORCE_REPLY = 1
+  struct GNUNET_HashCode auth;
+
 };
 
 
 /**
- * Message for a Key eXchange for a tunnel.
+ * Encrypted axolotl header with numbers that identify which
+ * keys in which ratchet are to be used to decrypt the body.
  */
-struct GNUNET_CADET_TunnelKeyExchangeMessage
+struct GNUNET_CADET_AxHeader
 {
-  /**
-   * Type: #GNUNET_MESSAGE_TYPE_CADET_TUNNEL_KX.
-   */
-  struct GNUNET_MessageHeader header;
 
   /**
-   * Flags for the key exchange in NBO, based on
-   * `enum GNUNET_CADET_KX_Flags`.
+   * Number of messages sent with the current ratchet key.
    */
-  uint32_t flags GNUNET_PACKED;
+  uint32_t Ns GNUNET_PACKED;
 
   /**
-   * ID of the connection.
+   * Number of messages sent with the previous ratchet key.
    */
-  struct GNUNET_CADET_ConnectionTunnelIdentifier cid;
+  uint32_t PNs GNUNET_PACKED;
 
   /**
-   * Sender's ephemeral public ECC key encoded in a
-   * format suitable for network transmission, as created
-   * using 'gcry_sexp_sprint'.
+   * Current ratchet key.
    */
-  struct GNUNET_CRYPTO_EcdhePublicKey ephemeral_key;
+  struct GNUNET_CRYPTO_EcdhePublicKey DHRs;
 
-  /**
-   * Sender's next ephemeral public ECC key encoded in a
-   * format suitable for network transmission, as created
-   * using 'gcry_sexp_sprint'.
-   */
-  struct GNUNET_CRYPTO_EcdhePublicKey ratchet_key;
 };
 
 
 /**
- * Axolotl tunnel message.
+ * Axolotl-encrypted tunnel message with application payload.
  */
-struct GNUNET_CADET_ConnectionEncryptedMessage
+struct GNUNET_CADET_TunnelEncryptedMessage
 {
   /**
-   * Type: #GNUNET_MESSAGE_TYPE_CONNECTION_ENCRYPTED
+   * Type: #GNUNET_MESSAGE_TYPE_CADET_TUNNEL_ENCRYPTED
    */
   struct GNUNET_MessageHeader header;
 
+#if NEW_CADET
+  /**
+   * Reserved, for alignment.
+   */
+  uint32_t reserved GNUNET_PACKED;
+#else
   /**
-   * ID of the packet (hop by hop).
+   * Maximum packet ID authorized.
    */
   struct CadetEncryptedMessageIdentifier cemi;
+#endif
 
   /**
    * ID of the connection.
@@ -309,8 +319,13 @@ struct GNUNET_CADET_ConnectionEncryptedMessage
    */
   struct GNUNET_ShortHashCode hmac;
 
-  /**************** AX_HEADER start ****************/
-
+  #if NEW_CADET
+  /**
+   * Axolotl-header that specifies which keys to use in which ratchet
+   * to decrypt the body that follows.
+   */
+  struct GNUNET_CADET_AxHeader ax_header;
+#else
   /**
    * Number of messages sent with the current ratchet key.
    */
@@ -325,29 +340,80 @@ struct GNUNET_CADET_ConnectionEncryptedMessage
    * Current ratchet key.
    */
   struct GNUNET_CRYPTO_EcdhePublicKey DHRs;
+#endif
+  /**
+   * Encrypted content follows.
+   */
+};
+
+
+#ifndef NEW_CADET
+
+/**
+ * Message to query a peer about its Flow Control status regarding a tunnel.
+ *
+ * It is NOT yet clear if we need this.
+ */
+struct GNUNET_CADET_ConnectionHopByHopPollMessage
+{
+  /**
+   * Type: #GNUNET_MESSAGE_TYPE_CADET_TUNNEL_ENCRYPTED_POLL
+   */
+  struct GNUNET_MessageHeader header;
 
-  /**************** AX_HEADER  end  ****************/
+  /**
+   * Last packet sent.
+   */
+  struct CadetEncryptedMessageIdentifier cemi;
 
   /**
-   * Encrypted content follows.
+   * ID of the connection.
    */
+  struct GNUNET_CADET_ConnectionTunnelIdentifier cid;
+
 };
 
 
+/**
+ * Message to acknowledge cadet encrypted traffic, used for
+ * flow-control on a hop-by-hop basis on the connection-level. Note
+ * that we do use the @e cemi from the tunnel layer as the connection
+ * layer's header is included/shared with the tunnel layer messages,
+ * and we only do flow control for the payload.
+ */
+struct GNUNET_CADET_ConnectionEncryptedAckMessage
+{
+  /**
+   * Type: #GNUNET_MESSAGE_TYPE_CADET_CONNECTION_HOP_BY_HOP_ENCRYPTED_ACK
+   */
+  struct GNUNET_MessageHeader header;
+
+  /**
+   * Maximum packet ID authorized.
+   */
+  struct CadetEncryptedMessageIdentifier cemi_max;
+
+  /**
+   * ID of the connection.
+   */
+  struct GNUNET_CADET_ConnectionTunnelIdentifier cid;
+};
+
+#endif
+
 
 /******************************************************************************/
 /*******************************   CHANNEL  ***********************************/
 /******************************************************************************/
 
-#ifndef NEW_CADET
 
 /**
  * Message to create a Channel.
  */
-struct GNUNET_CADET_ChannelCreateMessage
+struct GNUNET_CADET_ChannelOpenMessage
 {
   /**
-   * Type: #GNUNET_MESSAGE_TYPE_CADET_CHANNEL_CREATE
+   * Type: #GNUNET_MESSAGE_TYPE_CADET_CHANNEL_OPEN
    */
   struct GNUNET_MessageHeader header;
 
@@ -362,27 +428,36 @@ struct GNUNET_CADET_ChannelCreateMessage
   struct GNUNET_HashCode port;
 
   /**
-   * ID of the channel
+   * ID of the channel within the tunnel.
    */
-  struct GNUNET_CADET_ChannelNumber chid;
+  struct GNUNET_CADET_ChannelTunnelNumber ctn;
 };
 
-#endif
 
 /**
- * Message to manage a Channel (ACK, NACK, Destroy).
+ * Message to manage a Channel
+ * (#GNUNET_MESSAGE_TYPE_CADET_CHANNEL_OPEN_ACK,
+ * #GNUNET_MESSAGE_TYPE_CADET_CHANNEL_DESTROY).
  */
 struct GNUNET_CADET_ChannelManageMessage
 {
   /**
-   * Type: #GNUNET_MESSAGE_TYPE_CADET_CHANNEL_{ACK|NACK|DESTROY}
+   * Type: #GNUNET_MESSAGE_TYPE_CADET_CHANNEL_OPEN_ACK or
+   * #GNUNET_MESSAGE_TYPE_CADET_CHANNEL_DESTROY
    */
   struct GNUNET_MessageHeader header;
 
+#ifdef NEW_CADET
+  /**
+   * For alignment.
+   */
+  uint32_t reserved GNUNET_PACKED;
+#endif
+
   /**
    * ID of the channel
    */
-  struct GNUNET_CADET_ChannelNumber chid;
+  struct GNUNET_CADET_ChannelTunnelNumber ctn;
 };
 
 
@@ -391,7 +466,7 @@ struct GNUNET_CADET_ChannelManageMessage
 /**
  * Message for cadet data traffic.
  */
-struct GNUNET_CADET_ChannelDataMessage
+struct GNUNET_CADET_ChannelAppDataMessage
 {
   /**
    * Type: #GNUNET_MESSAGE_TYPE_CADET_UNICAST,
@@ -402,12 +477,13 @@ struct GNUNET_CADET_ChannelDataMessage
   /**
    * Unique ID of the payload message
    */
+  /* NEW: struct ChannelMessageIdentifier */
   uint32_t mid GNUNET_PACKED;
 
   /**
    * ID of the channel
    */
-  struct GNUNET_CADET_ChannelNumber chid;
+  struct GNUNET_CADET_ChannelTunnelNumber ctn;
 
   /**
    * Payload follows
@@ -421,17 +497,17 @@ struct GNUNET_CADET_ChannelDataMessage
 struct GNUNET_CADET_ChannelDataAckMessage
 {
   /**
-   * Type: #GNUNET_MESSAGE_TYPE_CADET_CHANNEL_DATA_ACK
+   * Type: #GNUNET_MESSAGE_TYPE_CADET_CHANNEL_APP_DATA_ACK
    */
   struct GNUNET_MessageHeader header;
 
   /**
    * ID of the channel
    */
-  struct GNUNET_CADET_ChannelNumber chid;
+  struct GNUNET_CADET_ChannelTunnelNumber ctn;
 
   /**
-   * Bitfield of already-received newer messages
+   * Bitfield of already-received messages past @e mid.
    * pid +  1 @ LSB
    * pid + 64 @ MSB
    */
@@ -440,9 +516,82 @@ struct GNUNET_CADET_ChannelDataAckMessage
   /**
    * Last message ID received.
    */
+  /* NEW: struct ChannelMessageIdentifier */
+  uint32_t mid GNUNET_PACKED;
+};
+
+#else
+
+
+/**
+ * Number used to uniquely identify messages in a CADET Channel.
+ */
+struct ChannelMessageIdentifier
+{
+  /**
+   * Unique ID of the message, cycles around, in NBO.
+   */
   uint32_t mid GNUNET_PACKED;
 };
 
+
+/**
+ * Message for cadet data traffic.
+ */
+struct GNUNET_CADET_ChannelAppDataMessage
+{
+  /**
+   * Type: #GNUNET_MESSAGE_TYPE_CADET_CHANNEL_APP_DATA.
+   */
+  struct GNUNET_MessageHeader header;
+
+  /**
+   * Unique ID of the payload message.
+   */
+  struct ChannelMessageIdentifier mid;
+
+  /**
+   * ID of the channel
+   */
+  struct GNUNET_CADET_ChannelTunnelNumber ctn;
+
+  /**
+   * Payload follows
+   */
+};
+
+
+/**
+ * Message to acknowledge end-to-end data.
+ */
+struct GNUNET_CADET_ChannelDataAckMessage
+{
+  /**
+   * Type: #GNUNET_MESSAGE_TYPE_CADET_CHANNEL_APP_DATA_ACK
+   */
+  struct GNUNET_MessageHeader header;
+
+  /**
+   * ID of the channel
+   */
+  struct GNUNET_CADET_ChannelTunnelNumber ctn;
+
+  /**
+   * Bitfield of already-received newer messages.  Note that bit 0
+   * corresponds to @e mid + 1.
+   *
+   * pid +  0 @ LSB
+   * pid + 63 @ MSB
+   */
+  uint64_t futures GNUNET_PACKED;
+
+  /**
+   * Next message ID expected.
+   */
+  struct ChannelMessageIdentifier mid;
+};
+
+
 #endif
 
 GNUNET_NETWORK_STRUCT_END