106 lines
4.2 KiB
C
106 lines
4.2 KiB
C
#ifndef PROTOCOL_MP1
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#define PROTOCOL_MP1
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#include <cfg/compiler.h>
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#include <io/kfile.h>
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// Options
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#define MP1_ENABLE_TCP_COMPATIBILITY false
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#if MP1_ENABLE_TCP_COMPATIBILITY
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#define MP1_ENABLE_COMPRESSION false
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#endif
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#define MP1_ENABLE_CSMA true
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// Frame sizing & checksum
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#define MP1_INTERLEAVE_SIZE 12
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#if MP1_ENABLE_COMPRESSION
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#define MP1_MAX_FRAME_LENGTH 22 * MP1_INTERLEAVE_SIZE
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#else
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#define MP1_MAX_FRAME_LENGTH 25 * MP1_INTERLEAVE_SIZE
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#define MP1_USE_TX_QUEUE true
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#define MP1_TX_QUEUE_LENGTH 2
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#define MP1_QUEUE_TX_WAIT 16UL
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#endif
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#define MP1_HEADER_SIZE 1
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#define MP1_CHECKSUM_SIZE 1
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#define MP1_MAX_DATA_SIZE MP1_MAX_FRAME_LENGTH - MP1_HEADER_SIZE - MP1_CHECKSUM_SIZE
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#define MP1_MIN_FRAME_LENGTH MP1_INTERLEAVE_SIZE
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#define MP1_DATA_BLOCK_SIZE ((MP1_INTERLEAVE_SIZE/3)*2)
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#define MP1_CHECKSUM_INIT 0xAA
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// These two parameters are used for
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// P-persistent CSMA
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#define MP1_SETTLE_TIME 175UL // The minimum wait time before considering sending
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#define MP1_SLOT_TIME 100UL // The time to wait if deciding not to send
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#define MP1_P_PERSISTENCE 85UL // The probability (between 0 and 255) for sending
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#define MP1_TXDELAY 0UL // Delay between turning on the transmitter and sending
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// We need to know some basic HDLC flag bytes
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#define HDLC_FLAG 0x7E
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#define HDLC_RESET 0x7F
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#define AX25_ESC 0x1B
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// We also define a few header flags and what
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// to send as padding if we need to pad a
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// packet. Due to forward error correction,
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// packets must have an even number of bytes.
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#define MP1_PADDING 0x55
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#define MP1_HEADER_PADDED 0x01
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#define MP1_HEADER_COMPRESSION 0x02
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// Just a forward declaration that this struct exists
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struct MP1Packet;
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// The type of a callback function for passing
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// back a decoded packet
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typedef void (*mp1_callback_t)(struct MP1Packet *packet);
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// Struct for a protocol context
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typedef struct MP1 {
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uint8_t buffer[MP1_MAX_FRAME_LENGTH+MP1_INTERLEAVE_SIZE]; // A buffer for incoming packets
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KFile *modem; // KFile access to the modem
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size_t packetLength; // Counter for received packet length
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size_t readLength; // This is the full read length, including parity bytes
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uint8_t calculatedParity; // Calculated parity for incoming data block
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mp1_callback_t callback; // The function to call when a packet has been received
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uint8_t checksum_in; // Rolling checksum for incoming packets
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uint8_t checksum_out; // Rolling checksum for outgoing packets
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bool reading; // True when we have seen a HDLC flag
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bool escape; // We need to know if we are in an escape sequence
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ticks_t settleTimer; // Timer used for carrier sense settling
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long correctionsMade; // A counter for how many corrections were made to a packet
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uint8_t interleaveCounter; // Keeps track of when we have received an entire interleaved block
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uint8_t interleaveOut[MP1_INTERLEAVE_SIZE]; // A buffer for interleaving bytes before they are sent
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uint8_t interleaveIn[MP1_INTERLEAVE_SIZE]; // A buffer for storing interleaved bytes before they are deinterleaved
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uint8_t randomSeed; // A seed for the pseudo-random number generator
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#if MP1_USE_TX_QUEUE
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bool queueProcessing; // For sending queued frames without preamble after first one
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size_t queueLength; // The length of the transmission queue
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size_t frameLengths[MP1_TX_QUEUE_LENGTH]; // The lengths of the frames in the queue
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uint8_t frameQueue[MP1_TX_QUEUE_LENGTH] // A buffer for a queued frame
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[MP1_MAX_DATA_SIZE];
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#endif
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} MP1;
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// A struct encapsulating a network packet
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typedef struct MP1Packet {
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const uint8_t *data; // Pointer to the actual data in the packet
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size_t dataLength; // The length of the received data
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} MP1Packet;
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// Declarations of functions
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void mp1Init(MP1 *mp1, KFile *modem, mp1_callback_t callback);
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void mp1Read(MP1 *mp1, int byte);
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void mp1Poll(MP1 *mp1);
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void mp1Send(MP1 *mp1, void *_buffer, size_t length);
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void mp1QueueFrame(MP1 *mp1, void *_buffer, size_t length);
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void mp1ProcessQueue(MP1 *mp1);
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bool mp1CarrierSense(MP1 *mp1);
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int freeRam(void);
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size_t compress(uint8_t *input, size_t length);
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size_t decompress(uint8_t *input, size_t length);
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void mp1Deinterleave(MP1 *mp1);
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void mp1Interleave(MP1 *mp1, uint8_t byte);
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#endif |