#ifndef PROTOCOL_MP1 #define PROTOCOL_MP1 #include #include // Frame sizing & checksum #define MP1_MIN_FRAME_LENGTH 3 #define MP1_MAX_FRAME_LENGTH 300 #define MP1_INTERLEAVE_SIZE 3 #define MP1_CHECKSUM_INIT 0xAA // We need to know some basic HDLC flag bytes #define HDLC_FLAG 0x7E #define HDLC_RESET 0x7F #define AX25_ESC 0x1B // We also define a few header flags and what // to send as padding if we need to pad a // packet. Due to forward error correction, // packets must have an even number of bytes. #define MP1_PADDING 0x55 #define MP1_HEADER_PADDED 0x01 #define MP1_HEADER_COMPRESSION 0x02 // Just a forward declaration that this struct exists struct MP1Packet; // The type of a callback function for passing // back a decoded packet typedef void (*mp1_callback_t)(struct MP1Packet *packet); // Struct for a protocol context typedef struct MP1 { uint8_t buffer[MP1_MAX_FRAME_LENGTH]; // A buffer for incoming packets uint8_t fecBuffer[3]; // FEC buffer KFile *modem; // KFile access to the modem size_t packetLength; // Counter for received packet length size_t readLength; // This is the full read length, including parity bytes uint8_t calculatedParity; // Calculated parity for incoming data block mp1_callback_t callback; // The function to call when a packet has been received uint8_t checksum_in; // Rolling checksum for incoming packets uint8_t checksum_out; // Rolling checksum for outgoing packets bool reading; // True when we have seen a HDLC flag bool escape; // We need to know if we are in an escape sequence long correctionsMade; // A counter for how many corrections were made to a packet uint8_t interleaveCounter; // Keeps track of when we have received an entire interleaved block uint8_t interleaveOut[MP1_INTERLEAVE_SIZE]; // A buffer for interleaving bytes before they are sent uint8_t interleaveIn[MP1_INTERLEAVE_SIZE]; // A buffer for storing interleaved bytes before they are deinterleaved } MP1; // A struct encapsulating a network packet typedef struct MP1Packet { const uint8_t *data; // Pointer to the actual data in the packet size_t dataLength; // The length of the received data } MP1Packet; // Declarations of functions void mp1Init(MP1 *mp1, KFile *modem, mp1_callback_t callback); void mp1Read(MP1 *mp1, int byte); void mp1Poll(MP1 *mp1); void mp1Send(MP1 *mp1, const void *_buffer, size_t length); int freeRam(void); size_t compress(uint8_t *input, size_t length); size_t decompress(uint8_t *input, size_t length); void mp1Deinterleave(MP1 *mp1); void mp1Interleave(MP1 *mp1, uint8_t byte); #endif