From a068d3a7e4b75a913ccdc4f4606a470c30d5f9e3 Mon Sep 17 00:00:00 2001
From: Sree Harsha Totakura <totakura@in.tum.de>
Date: Tue, 10 Jan 2012 23:18:38 +0000
Subject: stream P2P protocol message specification

---
 src/stream/stream_protocol.h | 190 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 190 insertions(+)
 create mode 100644 src/stream/stream_protocol.h

diff --git a/src/stream/stream_protocol.h b/src/stream/stream_protocol.h
new file mode 100644
index 000000000..20dae355b
--- /dev/null
+++ b/src/stream/stream_protocol.h
@@ -0,0 +1,190 @@
+/*
+     This file is part of GNUnet.
+     (C) 2012 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
+     by the Free Software Foundation; either version 3, or (at your
+     option) any later version.
+
+     GNUnet is distributed in the hope that it will be useful, but
+     WITHOUT ANY WARRANTY; without even the implied warranty of
+     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+     General Public License for more details.
+
+     You should have received a copy of the GNU General Public License
+     along with GNUnet; see the file COPYING.  If not, write to the
+     Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+     Boston, MA 02111-1307, USA.
+*/
+
+/**
+ * @file stream/stream_protocol.h
+ * @brief P2P protocol for the stream connections
+ * @author Sree Harsha Totakura
+ */
+
+#ifndef STREAM_PROTOCOL_H
+#define STREAM_PROTOCOL_H
+
+#ifdef	__cplusplus
+extern "C"
+{
+#if 0                           /* keep Emacsens' auto-indent happy */
+}
+#endif
+#endif
+
+#include <sys/types.h>
+
+#include "gnunet_stream_lib.h"
+#include "gnunet_mesh_service.h"
+
+
+/**
+ * Stream message types
+ */
+enum GNUNET_STREAM_MessageType
+  {
+    /**
+     * Message containing data
+     */
+    GNUNET_STREAM_MESSAGE_DATA,
+
+    /**
+     * ACK message
+     */
+    GNUNET_STREAM_MESSAGE_ACK,
+
+    /**
+     * Handshake hello message
+     */
+    GNUNET_STREAM_MESSAGE_HELLO,
+
+    /**
+     * Handshake hello acknowledgement message
+     */
+    GNUNET_STREAM_MESSAGE_HELLO_ACK,
+
+    /**
+     * Transmit close message (data transmission no longer possible after this
+     * message) 
+     */
+    GNUNET_STREAM_MESSAGE_TRANSMIT_CLOSE,
+
+    /**
+     * Transmit close acknowledgement message
+     */
+    GNUNET_STREAM_MESSAGE_TRANSMIT_CLOSE_ACK,
+    
+    /**
+     * Receive close message (data is no loger read by the receiver after this
+     * message) 
+     */
+    GNUNET_STREAM_MESSAGE_RECEIVE_CLOSE,
+
+    /**
+     * Receive close acknowledgement message
+     */
+    GNUNET_STREAM_MESSAGE_RECEIVE_CLOSE_ACK,
+
+    /**
+     * Stream close message (data is no longer sent or read after this message)
+     */
+    GNUNET_STREAM_MESSAGE_CLOSE,
+
+    /**
+     * Close acknowledgement message
+     */
+    GNUNET_STREAM_MESSAGE_CLOSE_ACK
+  };
+
+
+/**
+ * The stream message header
+ *
+ * The message can be of Data, Acknowledgement or both
+ */
+struct GNUNET_STREAM_MessageHeader
+{
+  /**
+   * The GNUNET message header
+   */
+  struct GNUNET_MessageHeader header;
+
+  /**
+   * A number which identifies a session
+   */
+  uint16_t session_id;
+
+  /**
+   * The message type
+   * ? Should we rather use the type field in GNUNET_MessageHeader ?
+   */
+  enum GNUNET_STREAM_MessageType type;
+
+};
+
+
+/**
+ * The Data message, should be prefixed with stream header with its type set to
+ * GNUNET_STREAM_Data 
+ */
+struct GNUNET_STREAM_DataMessage
+{
+  /**
+   * Sequence number; Always starts with 0 and should wrap around. 
+   * Immune to Sequence Prediction Attack as we take cover under GNUNET's secure
+   * messaging
+   */
+  uint32_t seq;
+
+  /**
+   * number of milliseconds to the soft deadline for sending acknowledgement
+   * measured from the time this message is received. It is optimal for the
+   * communication to send the ack within the soft deadline
+   */
+  uint16_t ack_deadline;
+
+  /**
+   * The data should be appended here
+   */
+};
+
+/**
+ * The Selective Acknowledgement Bitmap
+ * 
+ * ? WARNING ? Possibility for Denial of Service ??
+ * ? Receiver may force the sender to mantain a buffer of ~ 64*64k !??
+ */
+typedef uint64_t GNUNET_STREAM_AckBitmap;
+
+
+/**
+ * The Acknowledgment Message, should be prefixed with Stream Message header
+ * with its type set to GNUNET_STREAM_MESSAGE_ACK
+ */
+struct GNUNET_STREAM_AckMessage
+{
+  /**
+   * The sequence number of the Data Message upto which the receiver has filled
+   * its buffer without any missing packets
+   */
+  uint32_t base_seq;
+
+  /**
+   * The Selective Acknowledgement Bitmap. Computed relative to the base_seq
+   * (bit n corresponds to the Data message with sequence number base_seq+n)
+   */
+  GNUNET_STREAM_AckBitmap bitmap;
+};
+
+
+#if 0                           /** keep Emacsens' auto-indent happy */
+{
+#endif
+#ifdef __cplusplus
+}
+#endif
+
+#endif  /* STREAM_PROTOCOL_H */
-- 
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