* For now, only UI frames without any Layer 3 protocol are handled.
* This however is enough to send/receive APRS packets.
*
- * \version $Id$
* \author Francesco Sacchi <batt@develer.com>
*
*/
#define LOG_FORMAT AX25_LOG_FORMAT
#include <cfg/log.h>
-#include <string.h> //memset
+#include <string.h> //memset, memcmp
+#include <ctype.h> //isalnum, toupper
+
+#if CONFIG_AX25_RPT_LST
+ #define AX25_SET_REPEATED(msg, idx, val) \
+ do \
+ { \
+ if (val) \
+ (msg)->rpt_flags |= BV(idx) ; \
+ else \
+ (msg)->rpt_flags &= ~BV(idx) ; \
+ } while(0)
+#endif
#define DECODE_CALL(buf, addr) \
for (unsigned i = 0; i < sizeof((addr)); i++) \
{ \
- ASSERT(!(*(buf) & 0x01)); \
- (addr)[i] = *(buf)++ >> 1; \
+ char c = (*(buf)++ >> 1); \
+ (addr)[i] = (c == ' ') ? '\x0' : c; \
}
static void ax25_decode(AX25Ctx *ctx)
uint8_t *buf = ctx->buf;
DECODE_CALL(buf, msg.dst.call);
- ASSERT(!(*buf & 0x01));
msg.dst.ssid = (*buf++ >> 1) & 0x0F;
DECODE_CALL(buf, msg.src.call);
{
DECODE_CALL(buf, msg.rpt_lst[msg.rpt_cnt].call);
msg.rpt_lst[msg.rpt_cnt].ssid = (*buf >> 1) & 0x0F;
- LOG_INFO("RPT%d[%.6s-%d]\n", msg.rpt_cnt, msg.rpt_lst[msg.rpt_cnt].call, msg.rpt_lst[msg.rpt_cnt].ssid);
+ AX25_SET_REPEATED(&msg, msg.rpt_cnt, (*buf & 0x80));
+
+ LOG_INFO("RPT%d[%.6s-%d]%c\n", msg.rpt_cnt,
+ msg.rpt_lst[msg.rpt_cnt].call,
+ msg.rpt_lst[msg.rpt_cnt].ssid,
+ (AX25_REPEATED(&msg, msg.rpt_cnt) ? '*' : ' '));
}
#else
while (!(*buf++ & 0x01))
msg.ctrl = *buf++;
if (msg.ctrl != AX25_CTRL_UI)
{
- LOG_INFO("Only UI frames are handled, got [%02X]\n", msg.ctrl);
+ LOG_WARN("Only UI frames are handled, got [%02X]\n", msg.ctrl);
return;
}
msg.pid = *buf++;
if (msg.pid != AX25_PID_NOLAYER3)
{
- LOG_INFO("Only frames without layer3 protocol are handled, got [%02X]\n", msg.pid);
+ LOG_WARN("Only frames without layer3 protocol are handled, got [%02X]\n", msg.pid);
return;
}
msg.len = ctx->frm_len - 2 - (buf - ctx->buf);
msg.info = buf;
- LOG_INFO("DATA[%.*s]\n", msg.len, msg.info);
+ LOG_INFO("DATA: %.*s\n", msg.len, msg.info);
if (ctx->hook)
ctx->hook(&msg);
}
+
+/**
+ * Check if there are any AX25 messages to be processed.
+ * This function read available characters from the medium and search for
+ * any AX25 messages.
+ * If a message is found it is decoded and the linked callback executed.
+ * This function may be blocking if there are no available chars and the KFile
+ * used in \a ctx to access the medium is configured in blocking mode.
+ *
+ * \param ctx AX25 context to operate on.
+ */
void ax25_poll(AX25Ctx *ctx)
{
int c;
{
if (!ctx->escape && c == HDLC_FLAG)
{
- LOG_INFO("Frame start, frm_len %d\n", ctx->frm_len);
if (ctx->frm_len >= AX25_MIN_FRAME_LEN)
{
if (ctx->crc_in == AX25_CRC_CORRECT)
}
}
+static void ax25_putchar(AX25Ctx *ctx, uint8_t c)
+{
+ if (c == HDLC_FLAG || c == HDLC_RESET
+ || c == AX25_ESC)
+ kfile_putc(AX25_ESC, ctx->ch);
+ ctx->crc_out = updcrc_ccitt(c, ctx->crc_out);
+ kfile_putc(c, ctx->ch);
+}
+
+static void ax25_sendCall(AX25Ctx *ctx, const AX25Call *addr, bool last)
+{
+ unsigned len = MIN(sizeof(addr->call), strlen(addr->call));
+
+ for (unsigned i = 0; i < len; i++)
+ {
+ uint8_t c = addr->call[i];
+ ASSERT(isalnum(c) || c == ' ');
+ c = toupper(c);
+ ax25_putchar(ctx, c << 1);
+ }
+
+ /* Fill with spaces the rest of the CALL if it's shorter */
+ if (len < sizeof(addr->call))
+ for (unsigned i = 0; i < sizeof(addr->call) - len; i++)
+ ax25_putchar(ctx, ' ' << 1);
+
+ /* The bit7 "has-been-repeated" flag is not implemented here */
+ /* Bits6:5 should be set to 1 for all SSIDs (0x60) */
+ /* The bit0 of last call SSID should be set to 1 */
+ uint8_t ssid = 0x60 | (addr->ssid << 1) | (last ? 0x01 : 0);
+ ax25_putchar(ctx, ssid);
+}
+
+/**
+ * Send an AX25 frame on the channel through a specific path.
+ * \param ctx AX25 context to operate on.
+ * \param path An array of callsigns used as path, \see AX25_PATH for
+ * an handy way to create a path.
+ * \param path_len callsigns path lenght.
+ * \param _buf payload buffer.
+ * \param len length of the payload.
+ */
+void ax25_sendVia(AX25Ctx *ctx, const AX25Call *path, size_t path_len, const void *_buf, size_t len)
+{
+ const uint8_t *buf = (const uint8_t *)_buf;
+ ASSERT(path);
+ ASSERT(path_len >= 2);
+
+ ctx->crc_out = CRC_CCITT_INIT_VAL;
+ kfile_putc(HDLC_FLAG, ctx->ch);
+
+
+ /* Send call */
+ for (size_t i = 0; i < path_len; i++)
+ ax25_sendCall(ctx, &path[i], (i == path_len - 1));
+
+ ax25_putchar(ctx, AX25_CTRL_UI);
+ ax25_putchar(ctx, AX25_PID_NOLAYER3);
+
+ while (len--)
+ ax25_putchar(ctx, *buf++);
+
+ /*
+ * According to AX25 protocol,
+ * CRC is sent in reverse order!
+ */
+ uint8_t crcl = (ctx->crc_out & 0xff) ^ 0xff;
+ uint8_t crch = (ctx->crc_out >> 8) ^ 0xff;
+ ax25_putchar(ctx, crcl);
+ ax25_putchar(ctx, crch);
+
+ ASSERT(ctx->crc_out == AX25_CRC_CORRECT);
+
+ kfile_putc(HDLC_FLAG, ctx->ch);
+}
+
+static void print_call(KFile *ch, const AX25Call *call)
+{
+ kfile_printf(ch, "%.6s", call->call);
+ if (call->ssid)
+ kfile_printf(ch, "-%d", call->ssid);
+}
+
+/**
+ * Print a AX25 message in TNC-2 packet monitor format.
+ * \param ch a kfile channel where the message will be printed.
+ * \param msg the message to be printed.
+ */
+void ax25_print(KFile *ch, const AX25Msg *msg)
+{
+ print_call(ch, &msg->src);
+ kfile_putc('>', ch);
+ print_call(ch, &msg->dst);
+
+ #if CONFIG_AX25_RPT_LST
+ for (int i = 0; i < msg->rpt_cnt; i++)
+ {
+ kfile_putc(',', ch);
+ print_call(ch, &msg->rpt_lst[i]);
+ /* Print a '*' if packet has already been transmitted
+ * by this repeater */
+ if (AX25_REPEATED(msg, i))
+ kfile_putc('*', ch);
+ }
+ #endif
+
+ kfile_printf(ch, ":%.*s\n", msg->len, msg->info);
+}
+
+
+/**
+ * Init the AX25 protocol decoder.
+ *
+ * \param ctx AX25 context to init.
+ * \param channel Used to gain access to the physical medium
+ * \param hook Callback function called when a message is received
+ */
void ax25_init(AX25Ctx *ctx, KFile *channel, ax25_callback_t hook)
{
ASSERT(ctx);
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