imep_spec.h

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 * Ported from CMU/Monarch's code
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 * $Header: /nfs/jade/vint/CVSROOT/ns-2/imep/imep_spec.h,v 1.3 2000/09/01 03:04:10 haoboy Exp $
 */

#ifndef __imep_spec_h__
#define __imep_spec_h__

#include <sys/types.h>

// **********************************************************************
#ifdef COMMENT_ONLY

The Internet MANET Encapsulation Protocol (IMEP) consists of five
different mechanisms:
     Link/Connection Status Sensing
     Control Message Aggregation
     Broadcast Reliability
     Network-layer Address Resolution
     Security Authentication

04AUG98 - jgb - For now, I am going to implement the first three mechanisms
                as the last two are not really necessary for the present
                simulation work.

#endif /* COMMENT_ONLY */


// **********************************************************************
// Link/Connection Status Sensing


// IMEP may be configured to run in the following "connection
// notification" modes.
#define MODE_BIDIRECTIONAL  0x01
#define MODE_UNIDIRECTIONAL 0x02

// Link status
#define LINK_DOWN       0x00
#define LINK_IN         0x01
#define LINK_OUT        0x02
#define LINK_BI         (LINK_IN | LINK_OUT)

// XXX - The values for these constants are not specified by the IMEP draft.
#define BEACON_PERIOD       1.0             // seconds
#define BEACON_JITTER       0.010           // seconds
#define MAX_BEACON_TIME     (BEACON_PERIOD * 3)

// **********************************************************************
// Control Message Aggregation

// XXX - The values for these constants are not specified by the IMEP draft.
#define MAX_TRANSMIT_WAIT_TIME_LOWP 0.250           // seconds
#define MIN_TRANSMIT_WAIT_TIME_LOWP     0.150
#define MAX_TRANSMIT_WAIT_TIME_HIGHP    0.010           // seconds
#define MIN_TRANSMIT_WAIT_TIME_HIGHP    0.000

// **********************************************************************
// Broadcast Reliability
#define RETRANS_PERIOD      0.500           // seconds
#define MAX_REXMITS             2
#define MAX_RETRANS_TIME    (RETRANS_PERIOD * (MAX_REXMITS + 1))


// **********************************************************************
// Protocol Message Format

struct hdr_imep {
    u_int8_t          imep_version : 4;
    u_int8_t      imep_block_flags : 4;
    u_int16_t     imep_length;

    // Header access methods
    static int offset_; // required by PacketHeaderManager
    inline static int& offset() { return offset_; }
    inline static hdr_imep* access(const Packet* p) {
        return (hdr_imep*) p->access(offset_);
    }
};

/* hdr_imep actually takes 4 bytes, not 3, b/c we aren't packing the
   two bitfields into 1 byte */

#define IMEP_VERSION_0      0x00
#define IMEP_VERSION        IMEP_VERSION_0
#define BLOCK_FLAG_ACK      0x08
#define BLOCK_FLAG_HELLO    0x04
#define BLOCK_FLAG_OBJECT   0x02
#define BLOCK_FLAG_UNUSED   0x01

/* I'd rather not deal with alignment issues in this code, so I've
just padded out the IMEP structs to be word aligned.  The sizes of
packets will be slightly inflated, but the packet formats in the IMEP
draft are really odd --- I can't imagine anyone actually implementing them,
and they'd need to be padded out or redone in real life. -dam */

struct imep_ack {
    u_int8_t  ack_seqno;
        u_int8_t  r1;
        u_int16_t  r2;
    u_int32_t ack_ipaddr;
};

struct imep_ack_block {
    u_int8_t  ab_num_acks;
        u_int8_t  r1;
        u_int16_t  r2;
    char ab_ack_list[0];    // placeholder
};

struct imep_hello {
    u_int32_t  hello_ipaddr;
};

struct imep_hello_block {
    u_int8_t  hb_num_hellos;
        u_int8_t  r1;
        u_int16_t  r2;
    char hb_hello_list[0];  // placeholder
};

struct imep_object {
    u_int16_t   o_length;
    // The IMEP spec uses the first bit to determine if this field
    // is 8 or 16 bits.  I fix its length at 16 bits to keep
    // things simple.
    char        o_data[0];
};

struct imep_object_block {
    u_int8_t  ob_sequence;
    u_int8_t  ob_protocol_type : 4;
    u_int8_t  ob_num_objects : 7;
    u_int8_t  ob_num_responses : 5;
    char ob_object_list[0]; // placeholder
};

#define PROTO_RESERVED  0x00
#define PROTO_NARP  0x01
#define PROTO_RNARP 0x01
#define PROTO_TORA  0x02

// The "response list" follows the "object list" in an IMEP packet.
struct imep_response {
    u_int32_t  resp_ipaddr;
};

#endif /* __imep_spec_h__ */

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