KISS handling improvements

Inc/ax25.h

@@ -23,7 +23,8 @@ along with VP-Digi.  If not, see <http://www.gnu.org/licenses/>.
 #include <stdint.h>
 #include <stdbool.h>
 
-
+#define AX25_FRAME_MAX_SIZE (308) //single frame max length for RX
+//308 bytes is the theoretical max size assuming 2-byte Control, 256-byte info field and 5 digi address fields
 
 
 enum Ax25RxStage
@@ -43,12 +44,6 @@ struct Ax25ProtoConfig
 
 extern struct Ax25ProtoConfig Ax25Config;
 
-/**
- * @brief Transmit one or more frames encoded in KISS format
- * @param *buf Inout buffer
- * @param len Buffer size
- */
-void Ax25TxKiss(uint8_t *buf, uint16_t len);
 
 /**
  * @brief Write frame to transmit buffer

Inc/drivers/uart.h

@@ -25,7 +25,7 @@ along with VP-Digi.  If not, see <http://www.gnu.org/licenses/>.
 #include "usbd_cdc_if.h"
 #include "ax25.h"
 
-#define UART_BUFFER_SIZE 250
+#define UART_BUFFER_SIZE 130
 
 enum UartMode
 {
@@ -37,7 +37,6 @@ enum UartMode
 enum UartDataType
 {
 	DATA_NOTHING = 0,
-	DATA_KISS,
 	DATA_TERM,
 	DATA_USB,
 };
@@ -55,20 +54,14 @@ typedef struct
 	uint16_t txBufferHead, txBufferTail;
 	uint8_t txBufferFull : 1;
 	enum UartMode mode;
-	uint32_t kissTimer;
 	uint16_t lastRxBufferHead; //for special characters handling
+	uint8_t kissBuffer[AX25_FRAME_MAX_SIZE + 1];
+	uint16_t kissBufferHead;
 } Uart;
 
 extern Uart Uart1, Uart2, UartUsb;
 
 
-///**
-// * \brief Copy KISS frame(s) from input buffer to APRS TX buffer
-// * \param[in] *buf Input buffer
-// * \param[in] len Input buffer size
-// */
-//uint8_t Uart_txKiss(uint8_t *buf, uint16_t len);
-
 /**
  * @brief Send byte
  * @param[in] *port UART
@@ -113,11 +106,4 @@ void UartConfig(Uart *port, uint8_t state);
  */
 void UartClearRx(Uart *port);
 
-/**
- * @brief Handle KISS timeout
- * @param *port UART pointer
- * @attention This function must be polled constantly in main loop for USB UART.
- */
-void UartHandleKissTimeout(Uart *port);
-
 #endif

Inc/kiss.h

@@ -0,0 +1,41 @@
+/*
+Copyright 2020-2023 Piotr Wilkon
+
+This file is part of VP-Digi.
+
+VP-Digi is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 3 of the License, or
+(at your option) any later version.
+
+VP-Digi is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with VP-Digi.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#ifndef KISS_H_
+#define KISS_H_
+
+#include <stdint.h>
+#include "drivers/uart.h"
+
+/**
+ * @brief Convert AX.25 frame to KISS and send
+ * @param *port UART structure
+ * @param *buf Frame buffer
+ * @param size Frame size
+ */
+void KissSend(Uart *port, uint8_t *buf, uint16_t size);
+
+/**
+ * @brief Parse bytes received from UART to form a KISS frame (possibly) and send this frame
+ * @param *port UART structure
+ * @param data Received byte
+ */
+void KissParse(Uart *port, uint8_t data);
+
+#endif /* KISS_H_ */

Src/ax25.c

@@ -27,11 +27,9 @@ along with VP-Digi.  If not, see <http://www.gnu.org/licenses/>.
 
 struct Ax25ProtoConfig Ax25Config;
 
-//values below must be kept consistent so that FRAME_BUFFER_SIZE >= FRAME_MAX_SIZE * FRAME_MAX_COUNT
-#define FRAME_MAX_SIZE (308) //single frame max length for RX
-//308 bytes is the theoretical max size assuming 2-byte Control, 256-byte info field and 5 digi address fields
+
 #define FRAME_MAX_COUNT (10) //max count of frames in buffer
-#define FRAME_BUFFER_SIZE (FRAME_MAX_COUNT * FRAME_MAX_SIZE) //circular frame buffer length
+#define FRAME_BUFFER_SIZE (FRAME_MAX_COUNT * AX25_FRAME_MAX_SIZE) //circular frame buffer length
 
 #define STATIC_HEADER_FLAG_COUNT 4 //number of flags sent before each frame
 #define STATIC_FOOTER_FLAG_COUNT 8 //number of flags sent after each frame
@@ -98,7 +96,7 @@ static enum TxStage txStage; //current TX stage
 struct RxState
 {
 	uint16_t crc; //current CRC
-	uint8_t frame[FRAME_MAX_SIZE]; //raw frame buffer
+	uint8_t frame[AX25_FRAME_MAX_SIZE]; //raw frame buffer
 	uint16_t frameIdx; //index for raw frame buffer
 	uint8_t receivedByte; //byte being currently received
 	uint8_t receivedBitIdx; //bit index for recByte
@@ -115,7 +113,7 @@ static uint16_t rxMultiplexDelay = 0; //simple delay for decoder multiplexer to
 static uint16_t txDelay; //number of TXDelay bytes to send
 static uint16_t txTail; //number of TXTail bytes to send
 
-static uint8_t outputFrameBuffer[FRAME_MAX_SIZE];
+static uint8_t outputFrameBuffer[AX25_FRAME_MAX_SIZE];
 
 #define GET_FREE_SIZE(max, head, tail) (((head) < (tail)) ? ((tail) - (head)) : ((max) - (head) + (tail)))
 #define GET_USED_SIZE(max, head, tail) (max - GET_FREE_SIZE(max, head, tail))
@@ -146,62 +144,6 @@ void Ax25ClearReceivedFrameBitmap(void)
 	frameReceived = 0;
 }
 
-void Ax25TxKiss(uint8_t *buf, uint16_t len)
-{
-	if(len < 18) //frame is too small
-	{
-		return;
-	}
-	for(uint16_t i = 0; i < len; i++)
-	{
-		if((buf[i] == 0xC0) && ((buf[i + 1] & 0xF) == 0)) //frame start marker and type is data frame
-		{
-			i += 2; //skip 0xC0 and type
-			uint16_t end = i;
-			while(end < len)
-			{
-				if(buf[end] == 0xC0)
-					break;
-				end++;
-			}
-			if(end == len) //no frame end marker found
-				return;
-
-			uint16_t modifiedEnd = end;
-
-			for(uint16_t j = i; j < modifiedEnd; j++)
-			{
-				if(buf[j] == 0xDB) //escape character
-				{
-					if(buf[j + 1] == 0xDC) //transposed frame end
-					{
-						buf[j] = 0xC0;
-					}
-					else if(buf[j + 1] == 0xDD) //transposed frame escape
-					{
-						buf[j] = 0xDB;
-					}
-					else
-					{
-						j++;
-						continue;
-					}
-
-					j++;
-					modifiedEnd--;
-					for(uint16_t k = j; k < modifiedEnd; k++)
-					{
-						buf[k] = buf[k + 1];
-					}
-				}
-			}
-
-			Ax25WriteTxFrame(&buf[i], modifiedEnd - i); //skip modem number and send frame
-			DigiStoreDeDupe(&buf[i], modifiedEnd - i);
-			i = end; //move pointer to the next byte if there are more consecutive frames
-		}
-	}
-}
 
 void *Ax25WriteTxFrame(uint8_t *data, uint16_t size)
 {
@@ -340,7 +282,7 @@ void Ax25BitParse(uint8_t bit, uint8_t modem)
 	}
 
 
-	if((rx->rawData & 0x7F) == 0x7F) //received 7 consecutive ones, this is an error (sometimes called "escape byte")
+	if((rx->rawData & 0x7F) == 0x7F) //received 7 consecutive ones, this is an error
 	{
 		rx->rx = RX_STAGE_FLAG;
 		ModemClearRMS(modem);
@@ -365,7 +307,7 @@ void Ax25BitParse(uint8_t bit, uint8_t modem)
 
 	if(++rx->receivedBitIdx >= 8) //received full byte
 	{
-		if(rx->frameIdx > FRAME_MAX_SIZE) //frame is too long
+		if(rx->frameIdx > AX25_FRAME_MAX_SIZE) //frame is too long
 		{
 			rx->rx = RX_STAGE_IDLE;
 			ModemClearRMS(modem);

Src/digipeater.c

@@ -52,8 +52,7 @@ static struct DeDupeData deDupe[DEDUPE_SIZE]; //duplicate protection hash buffer
 static uint8_t deDupeCount = 0; //duplicate protection buffer index
 
 
-#define DIGI_BUFFER_SIZE 308 //308 is the theoretical max under some assumptions, see ax25.c
-static uint8_t buf[DIGI_BUFFER_SIZE];
+static uint8_t buf[AX25_FRAME_MAX_SIZE];
 
 /**
  * @brief Check if frame with specified hash is already in viscous-delay buffer and delete it if so

Src/drivers/uart.c

@@ -24,6 +24,7 @@ along with VP-Digi.  If not, see <http://www.gnu.org/licenses/>.
 #include "common.h"
 #include <string.h>
 #include "digipeater.h"
+#include "kiss.h"
 
 Uart Uart1, Uart2, UartUsb;
 
@@ -32,28 +33,21 @@ static void handleInterrupt(Uart *port)
 	if(port->port->SR & USART_SR_RXNE) //byte received
 	{
 		port->port->SR &= ~USART_SR_RXNE;
-		port->rxBuffer[port->rxBufferHead++] = port->port->DR; //store it
+		uint8_t data = port->port->DR;
+		port->rxBuffer[port->rxBufferHead++] = data; //store it
 		port->rxBufferHead %= UART_BUFFER_SIZE;
 
+		KissParse(port, data);
 		TermHandleSpecial(port);
-
-		if(port->mode == MODE_KISS)
-			port->kissTimer = SysTickGet() + (5000 / SYSTICK_INTERVAL); //set timeout to 5s in KISS mode
 	}
 	if(port->port->SR & USART_SR_IDLE) //line is idle, end of data reception
 	{
 		port->port->DR; //reset idle flag by dummy read
 		if(port->rxBufferHead != 0)
 		{
-			if((port->rxBuffer[0] == 0xC0) && (port->rxBuffer[port->rxBufferHead - 1] == 0xC0)) //data starts with 0xc0 and ends with 0xc0 - this is a KISS frame
-			{
-				port->rxType = DATA_KISS;
-				port->kissTimer = 0;
-			}
-			else if(((port->rxBuffer[port->rxBufferHead - 1] == '\r') || (port->rxBuffer[port->rxBufferHead - 1] == '\n'))) //data ends with \r or \n, process as data
+			if(((port->rxBuffer[port->rxBufferHead - 1] == '\r') || (port->rxBuffer[port->rxBufferHead - 1] == '\n'))) //data ends with \r or \n, process as data
 			{
 				port->rxType = DATA_TERM;
-				port->kissTimer = 0;
 			}
 		}
 	}
@@ -61,7 +55,7 @@ static void handleInterrupt(Uart *port)
 	{
 		if((port->txBufferHead != port->txBufferTail) || port->txBufferFull) //if there is anything to transmit
 		{
-			port->port->DR = port->txBuffer[port->txBufferTail++]; //push it to the refister
+			port->port->DR = port->txBuffer[port->txBufferTail++]; //push it to the register
 			port->txBufferTail %= UART_BUFFER_SIZE;
 			port->txBufferFull = 0;
 		}
@@ -70,13 +64,6 @@ static void handleInterrupt(Uart *port)
 			port->port->CR1 &= ~USART_CR1_TXEIE;
 		}
 	}
-
-	if((port->kissTimer > 0) && (SysTickGet() >= port->kissTimer)) //KISS timer timeout
-	{
-		port->kissTimer = 0;
-		port->rxBufferHead = 0;
-		memset(port->rxBuffer, 0, sizeof(port->rxBuffer));
-	}
 }
 
 void USART1_IRQHandler(void) __attribute__ ((interrupt));
@@ -160,12 +147,13 @@ void UartInit(Uart *port, USART_TypeDef *uart, uint32_t baud)
 	port->txBufferHead = 0;
 	port->txBufferTail = 0;
 	port->txBufferFull = 0;
+	port->kissBufferHead = 0;
 	port->mode = MODE_KISS;
 	port->enabled = 0;
-	port->kissTimer = 0;
 	port->lastRxBufferHead = 0;
 	memset(port->rxBuffer, 0, sizeof(port->rxBuffer));
 	memset(port->txBuffer, 0, sizeof(port->txBuffer));
+	memset(port->kissBuffer, 0, sizeof(port->kissBuffer));
 }
 
 
@@ -236,13 +224,3 @@ void UartClearRx(Uart *port)
 	port->rxBufferHead = 0;
 	port->rxType = DATA_NOTHING;
 }
-
-void UartHandleKissTimeout(Uart *port)
-{
-	if((port->kissTimer > 0) && (SysTickGet() >= port->kissTimer)) //KISS timer timeout
-	{
-		port->kissTimer = 0;
-		port->rxBufferHead = 0;
-		memset(port->rxBuffer, 0, sizeof(port->rxBuffer));
-	}
-}

Src/kiss.c

@@ -0,0 +1,98 @@
+/*
+Copyright 2020-2023 Piotr Wilkon
+
+This file is part of VP-Digi.
+
+VP-Digi is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 3 of the License, or
+(at your option) any later version.
+
+VP-Digi is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with VP-Digi.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include "kiss.h"
+#include "ax25.h"
+#include "digipeater.h"
+
+void KissSend(Uart *port, uint8_t *buf, uint16_t size)
+{
+	if(port->mode == MODE_KISS)
+	{
+		UartSendByte(port, 0xC0);
+		UartSendByte(port, 0x00);
+		for(uint16_t i = 0; i < size; i++)
+		{
+			if(buf[i] == 0xC0) //frame end in data
+			{
+				UartSendByte(port, 0xDB); //frame escape
+				UartSendByte(port, 0xDC); //transposed frame end
+			}
+			else if(buf[i] == 0xDB) //frame escape in data
+			{
+				UartSendByte(port, 0xDB); //frame escape
+				UartSendByte(port, 0xDD); //transposed frame escape
+			}
+			else
+				UartSendByte(port, buf[i]);
+		}
+		UartSendByte(port, 0xC0);
+	}
+}
+
+
+void KissParse(Uart *port, uint8_t data)
+{
+	if(data == 0xC0) //frame end marker
+	{
+		if(port->kissBufferHead < 17) //command+source+destination+PID+Control=17
+		{
+			port->kissBufferHead = 0;
+			return;
+		}
+
+		if((port->kissBuffer[0] & 0xF) != 0) //check if this is an actual frame
+		{
+			port->kissBufferHead = 0;
+			return;
+		}
+
+		//simple sanity check
+		//check if LSbits in the first 13 bytes are set to 0
+		//they should always be in an AX.25 frame
+		for(uint8_t i = 0; i < 13; i++)
+		{
+			if((port->kissBuffer[i + 1] & 1) != 0)
+			{
+				port->kissBufferHead = 0;
+				return;
+			}
+		}
+
+		Ax25WriteTxFrame(&port->kissBuffer[1], port->kissBufferHead - 1);
+		DigiStoreDeDupe(&port->kissBuffer[1], port->kissBufferHead - 1);
+		port->kissBufferHead = 0;
+		return;
+	}
+	else if(port->kissBufferHead > 0)
+	{
+		if((data == 0xDC) && (port->kissBuffer[port->kissBufferHead - 1] == 0xDB)) //escape character with transposed frame end
+		{
+			port->kissBuffer[port->kissBufferHead - 1] = 0xC0;
+			return;
+		}
+		else if((data == 0xDD) && (port->kissBuffer[port->kissBufferHead - 1] == 0xDB)) //escape character with transposed escape character
+		{
+			port->kissBuffer[port->kissBufferHead - 1] = 0xDB;
+			return;
+		}
+	}
+	port->kissBuffer[port->kissBufferHead++] = data;
+	port->kissBufferHead %= sizeof(port->kissBuffer);
+}

Src/main.c

@@ -290,7 +290,6 @@ int main(void)
 		  TermParse(&Uart2);
 		  UartClearRx(&Uart2);
 	  }
-	  UartHandleKissTimeout(&UartUsb);
 
 	  BeaconCheck(); //check beacons
 

Src/terminal.c

@@ -25,6 +25,7 @@ along with VP-Digi.  If not, see <http://www.gnu.org/licenses/>.
 #include "drivers/modem.h"
 #include "ax25.h"
 #include "drivers/systick.h"
+#include "kiss.h"
 
 void TermHandleSpecial(Uart *u)
 {
@@ -60,38 +61,13 @@ void TermHandleSpecial(Uart *u)
 }
 
 
-static void sendKiss(Uart *port, uint8_t *buf, uint16_t len)
-{
-	if(port->mode == MODE_KISS)
-	{
-		UartSendByte(port, 0xC0);
-		UartSendByte(port, 0x00);
-		for(uint16_t i = 0; i < len; i++)
-		{
-			if(buf[i] == 0xC0) //frame end in data
-			{
-				UartSendByte(port, 0xDB); //frame escape
-				UartSendByte(port, 0xDC); //transposed frame end
-			}
-			else if(buf[i] == 0xDB) //frame escape in data
-			{
-				UartSendByte(port, 0xDB); //frame escape
-				UartSendByte(port, 0xDD); //transposed frame escape
-			}
-			else
-				UartSendByte(port, buf[i]);
-		}
-		UartSendByte(port, 0xC0);
-	}
-}
-
 void TermSendToAll(enum UartMode mode, uint8_t *data, uint16_t size)
 {
 	if(MODE_KISS == mode)
 	{
-		sendKiss(&Uart1, data, size);
-		sendKiss(&Uart2, data, size);
-		sendKiss(&UartUsb, data, size);
+		KissSend(&Uart1, data, size);
+		KissSend(&Uart2, data, size);
+		KissSend(&UartUsb, data, size);
 	}
 	else if(MODE_MONITOR == mode)
 	{
@@ -119,9 +95,6 @@ void TermSendNumberToAll(enum UartMode mode, int32_t n)
 
 }
 
-
-
-
 static const char monitorHelp[] = "\r\nCommans available in monitor mode:\r\n"
 		"help - shows this help page\r\n"
 		"cal {low|high|alt|stop} - transmits/stops transmitter calibration pattern\r\n"
@@ -391,14 +364,6 @@ void TermParse(Uart *src)
 		src->mode = MODE_MONITOR;
 		return;
 	}
-	/*
-	 * KISS parsing
-	 */
-	else if((src->mode == MODE_KISS) && (src->rxType == DATA_KISS))
-	{
-		Ax25TxKiss(src->rxBuffer, src->rxBufferHead);
-		return;
-	}
 	/*
 	 * Monitor mode handling
 	 */

Src/usbd_cdc_if.c

@@ -26,6 +26,7 @@
 #include "drivers/uart.h"
 #include "drivers/systick.h"
 #include "terminal.h"
+#include "kiss.h"
 /* USER CODE END INCLUDE */
 
 /* Private typedef -----------------------------------------------------------*/
@@ -274,6 +275,7 @@ static int8_t CDC_Receive_FS(uint8_t* Buf, uint32_t *Len)
 	for(uint16_t i = 0; i < *Len; i++)
 	{
 		UartUsb.rxBuffer[UartUsb.rxBufferHead++] = Buf[i];
+		KissParse(&UartUsb, Buf[i]);
 		UartUsb.rxBufferHead %= UART_BUFFER_SIZE;
 	}
 
@@ -322,20 +324,11 @@ uint8_t CDC_Transmit_FS(uint8_t* Buf, uint16_t Len)
 /* USER CODE BEGIN PRIVATE_FUNCTIONS_IMPLEMENTATION */
 static void handleUsbInterrupt(Uart *port)
 {
-	if(port->mode == MODE_KISS)
-		port->kissTimer = SysTickGet() + (5000 / SYSTICK_INTERVAL); //set timeout to 5s in KISS mode
-
 	if(port->rxBufferHead != 0)
 	{
-		if((port->rxBuffer[0] == 0xC0) && (port->rxBuffer[port->rxBufferHead - 1] == 0xC0)) //data starts with 0xc0 and ends with 0xc0 - this is a KISS frame
-		{
-			port->rxType = DATA_KISS;
-			port->kissTimer = 0;
-		}
-		else if(((port->rxBuffer[port->rxBufferHead - 1] == '\r') || (port->rxBuffer[port->rxBufferHead - 1] == '\n'))) //data ends with \r or \n, process as data
+		if(((port->rxBuffer[port->rxBufferHead - 1] == '\r') || (port->rxBuffer[port->rxBufferHead - 1] == '\n'))) //data ends with \r or \n, process as data
 		{
 			port->rxType = DATA_TERM;
-			port->kissTimer = 0;
 		}
 	}
 }