packet.h

Open DMT Client C Source code

    /* Diagnostic packets */
    PKT_CLIENT_DIAGNOSTIC               = PKT_CLIENT_HEADER|0xD0,    // Diagnostic codes
        // Payload:
        //   0:2 - Diagnostic code
        //   2:X - Diagnostic data

    /* Error packets */
    PKT_CLIENT_ERROR                    = PKT_CLIENT_HEADER|0xE0,    // Error codes
        // Payload:
        //   0:2 - Error code
        //   2:X - Error data

    /* File download packets? */
    
};
typedef enum ClientPacketType_enum ClientPacketType_t;

// ----------------------------------------------------------------------------
// Server originated packets

#define PKT_SERVER_HEADER               ((UInt16)PACKET_HEADER_SERVER_BASIC << 8)
enum ServerPacketType_enum {
    
    /* End-Of-Block packets */
    PKT_SERVER_EOB_DONE                 = PKT_SERVER_HEADER|0x00,    // ""       : End of transmission, query response
        // Payload:
        //   0:1 - Optional maximum number of events to send per block
        //   1:X - Optional server key
    PKT_SERVER_EOB_SPEAK_FREELY         = PKT_SERVER_HEADER|0x01,    // ""       : End of transmission, speak freely
        // Payload:
        //   0:1 - Optional maximum number of events to send per block
        //   1:X - Optional server key
        // The client may treat this packet the same as PKT_SERVER_EOB_DONE

    /* Acknowledge packet */
    PKT_SERVER_ACK                      = PKT_SERVER_HEADER|0xA0,    // "%*u"    : Acknowledge
        // Payload:
        //   0:X - Acknowledged sequence

    /* Property packets */
    PKT_SERVER_GET_PROPERTY             = PKT_SERVER_HEADER|0xB0,    // "%2u"    : Get property
        // Payload:
        //   0:2 - Property ID
    PKT_SERVER_SET_PROPERTY             = PKT_SERVER_HEADER|0xB1,    // "%2u%*b" : Set property
        // Payload:
        //   0:2 - Property ID
        //   2:X - Property value
    /* File upload packets */
    PKT_SERVER_FILE_UPLOAD              = PKT_SERVER_HEADER|0xC0,    // "%1x%3u%*b" : File upload
        // Payload:
        //   0:1 - Start/Data/End indicator
        //   1:3 - File length/offset
        //   4:X - Filename/Data/Checksum
        // The client may choose to ignore this packet

    /* Error packets */
    PKT_SERVER_ERROR                    = PKT_SERVER_HEADER|0xE0,    // "%2u"    : NAK/Error codes
        // Payload:
        //   0:2 - Error code
        //   2:2 - Offending packet header
        //   4:2 - Ofending packet type
        //   6:X - Optional error data

    /* End-Of-Transmission */
    PKT_SERVER_EOT                      = PKT_SERVER_HEADER|0xFF,    // ""       : End transmission (socket will be closed)
        // Payload:
        //  (None)

};
typedef enum ServerPacketType_enum ServerPacketType_t;

// ----------------------------------------------------------------------------

typedef struct {
    ServerPacketType_t      pktType;
    char                    *format;
    UInt16                  flags;
} ServerPacketEntry_t;

// ----------------------------------------------------------------------------

#define PACKET_MAX_ENCODED_LENGTH       600 // (with excess) largest possible ASCII encoded packet

// ----------------------------------------------------------------------------

enum PacketPriority_enum { 
    PRIORITY_NONE       = 0, 
    PRIORITY_LOW        = 1,    // generally sent via Simplex only (GPRS)
    PRIORITY_NORMAL     = 2,    // generally sent via Duplex  only (GPRS)
    PRIORITY_HIGH       = 3     // generally sent via Duplex  only (GPRS, then Satellite)
};
typedef enum PacketPriority_enum PacketPriority_t;

// ----------------------------------------------------------------------------

#define ENCODING_BASE64_CHAR        '='
#define ENCODING_HEX_CHAR           ':'
#define ENCODING_CSV_CHAR           ','

#define ENCODING_ASCII_CKSUM_       (0x8000)
#define ENCODING_IS_CHECKSUM(E)     (((E) & ENCODING_ASCII_CKSUM_) != 0)
#define ENCODING_IS_ASCII(E)        (ENCODING_VALUE(E) != ENCODING_BINARY)
#define ENCODING_VALUE(E)           ((E) & 0x0F)
#define ENCODING_CHECKSUM(E)        (ENCODING_VALUE(E) | ENCODING_ASCII_CKSUM_)

#define ENCODING_MASK(E)            (1 << ENCODING_VALUE(E))

#define ENCODING_BINARY             0    // server must support
#define ENCODING_BINARY_MASK        ENCODING_MASK(ENCODING_BINARY)  // 0x01

#define ENCODING_BASE64             1    // server must support
#define ENCODING_BASE64_CKSUM       ENCODING_CHECKSUM(ENCODING_BASE64)
#define ENCODING_BASE64_MASK        ENCODING_MASK(ENCODING_BASE64)  // 0x02

#define ENCODING_HEX                2    // server must support
#define ENCODING_HEX_CKSUM          ENCODING_CHECKSUM(ENCODING_HEX)
#define ENCODING_HEX_MASK           ENCODING_MASK(ENCODING_HEX)     // 0x04

#define ENCODING_CSV                3    // server support optional
#define ENCODING_CSV_CKSUM          ENCODING_CHECKSUM(ENCODING_CSV)
#define ENCODING_CSV_MASK           ENCODING_MASK(ENCODING_CSV)

#define ENCODING_UNDEFINED          (0xFFFF)

#define ENCODING_REQUIRED_MASK      (ENCODING_BINARY_MASK | ENCODING_BASE64_MASK | ENCODING_HEX_MASK)
#define ENCODING_ALL_MASK           (ENCODING_REQUIRED_MASK | ENCODING_CSV_MASK)

typedef UInt16 PacketEncoding_t;

// ----------------------------------------------------------------------------
// Internal packet function error codes

#define PKTERR_NULL_PACKET          -301    // internal
#define PKTERR_BIN_PRINTF           -302    // internal: buffer overflow or invalid format
#define PKTERR_ENCODING             -303    // internal: packet encoding error
#define PKTERR_OVERFLOW             -304    // internal: buffer overflow
#define PKTERR_BIN_FORMAT_DIGIT     -331    // internal: invalid format digit
#define PKTERR_BIN_FORMAT_CHAR      -332    // internal: invalid format char

// ----------------------------------------------------------------------------

// this value is used to indicate that 'all' sent event packets are to be acknowledged
#define SEQUENCE_ALL            0xFFFFFFFFL

#define SEQUENCE_MASK(N)        ((1L << ((N) * 8)) - 1L)

// ----------------------------------------------------------------------------

typedef struct {
    UInt32              sequence;   // sequence number (MUST MATCH PACKET ENCODED SEQUENCE!!!)
    ClientPacketType_t  hdrType;    // packet type (ie. EVENT_FIXED_FORMAT_TYPE)
    PacketPriority_t    priority;   // low/normal/high priority
    utBool              sent;       // 'true' if sent to server
    UInt8               seqPos;     // sequence position
    UInt8               seqLen;     // sequence length
    char                dataFmt[(PACKET_MAX_FIELD_COUNT * 3) + 3]; // null terminated
    UInt8               dataLen;    // length of data in payload
    UInt8               data[PACKET_MAX_PAYLOAD_LENGTH];
} Packet_t; // sizeof(Packet_t) == 324 bytes

// ----------------------------------------------------------------------------
// ----------------------------------------------------------------------------

utBool pktIsEventPacket(ClientPacketType_t pht);

FmtBuffer_t *pktFmtBuffer(FmtBuffer_t *bf, Packet_t *pkt);

int pktInit(Packet_t *pkt, ClientPacketType_t pktType, const char *fmt, ...);
int pktVInit(Packet_t *pkt, ClientPacketType_t pktType, const char *fmt, va_list ap);

int pktEncodePacket(Buffer_t *dest, Packet_t *pkt, PacketEncoding_t encoding);

void pktPrintPacket(Packet_t *pkt, const char *msg, PacketEncoding_t encoding);

// ----------------------------------------------------------------------------
// ----------------------------------------------------------------------------

#ifdef __cplusplus
}
#endif
#endif