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88 lines
2.6 KiB
88 lines
2.6 KiB
// Based on work by Francesco Sacchi
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#include <string.h>
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#include <ctype.h>
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#include "AX25.h"
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#include "protocol/HDLC.h"
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#include "util/CRC-CCIT.h"
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#include "../hardware/AFSK.h"
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#define countof(a) sizeof(a)/sizeof(a[0])
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#define MIN(a,b) ({ typeof(a) _a = (a); typeof(b) _b = (b); ((typeof(_a))((_a < _b) ? _a : _b)); })
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#define DECODE_CALL(buf, addr) for (unsigned i = 0; i < sizeof((addr)); i++) { char c = (*(buf)++ >> 1); (addr)[i] = (c == ' ') ? '\x0' : c; }
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#define AX25_SET_REPEATED(msg, idx, val) do { if (val) { (msg)->rpt_flags |= _BV(idx); } else { (msg)->rpt_flags &= ~_BV(idx) ; } } while(0)
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void ax25_init(AX25Ctx *ctx, FILE *channel, ax25_callback_t hook) {
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memset(ctx, 0, sizeof(*ctx));
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ctx->ch = channel;
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ctx->hook = hook;
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ctx->crc_in = ctx->crc_out = CRC_CCIT_INIT_VAL;
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}
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static void ax25_decode(AX25Ctx *ctx) {
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#if SERIAL_PROTOCOL == PROTOCOL_KISS
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if (ctx->hook) ctx->hook(ctx);
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#endif
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}
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void ax25_poll(AX25Ctx *ctx) {
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int c;
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while ((c = fgetc(ctx->ch)) != EOF) {
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if (!ctx->escape && c == HDLC_FLAG) {
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if (ctx->frame_len >= AX25_MIN_FRAME_LEN) {
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if (ctx->crc_in == AX25_CRC_CORRECT) {
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#if OPEN_SQUELCH == true
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LED_RX_ON();
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#endif
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ax25_decode(ctx);
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}
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}
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ctx->sync = true;
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ctx->crc_in = CRC_CCIT_INIT_VAL;
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ctx->frame_len = 0;
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continue;
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}
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if (!ctx->escape && c == HDLC_RESET) {
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ctx->sync = false;
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continue;
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}
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if (!ctx->escape && c == AX25_ESC) {
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ctx->escape = true;
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continue;
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}
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if (ctx->sync) {
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if (ctx->frame_len < AX25_MAX_FRAME_LEN) {
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ctx->buf[ctx->frame_len++] = c;
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ctx->crc_in = update_crc_ccit(c, ctx->crc_in);
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} else {
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ctx->sync = false;
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}
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}
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ctx->escape = false;
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}
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}
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static void ax25_putchar(AX25Ctx *ctx, uint8_t c)
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{
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if (c == HDLC_FLAG || c == HDLC_RESET || c == AX25_ESC) fputc(AX25_ESC, ctx->ch);
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ctx->crc_out = update_crc_ccit(c, ctx->crc_out);
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fputc(c, ctx->ch);
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}
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void ax25_sendRaw(AX25Ctx *ctx, void *_buf, size_t len) {
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ctx->crc_out = CRC_CCIT_INIT_VAL;
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fputc(HDLC_FLAG, ctx->ch);
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const uint8_t *buf = (const uint8_t *)_buf;
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while (len--) ax25_putchar(ctx, *buf++);
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uint8_t crcl = (ctx->crc_out & 0xff) ^ 0xff;
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uint8_t crch = (ctx->crc_out >> 8) ^ 0xff;
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ax25_putchar(ctx, crcl);
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ax25_putchar(ctx, crch);
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fputc(HDLC_FLAG, ctx->ch);
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}
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