Fixed some nasty repeater-flag problems

CHANGELOG.md

@@ -36,3 +36,11 @@ All notable changes to this project will be documented in this file.
 
 ### Removed
 - Config.py as configuration is now completely removed. Configuration is now done completely via RPi-LoRa-KISS-TNC.ini
+
+## [0.0.4] - 2024-01-18
+
+Should now be possible to use it as a real digipeater with aprx software
+
+### Fixed
+- Added '*' to LoRa APRS TX string when the 'has-been-repeated' flag of the repeater(s) in the AX.25 frame is set.
+- Proper handling of 'has-been-repeated' asterix in LoRa RX frames, also when no SSID is received

KissHelper.py

@@ -30,6 +30,7 @@
 #
 # 2022-01-23: - in encode_address() added correct handling of has_been_repeated flag '*'
 # 2022-01-28: - in encode_kiss() and encode_address(): better exeption handling for corrupted or mal-formatted APRS frames
+# 2024-01-18: - in decode_kiss() add '*' to call when 'has-been-repeated' flag is set for reapeters
 #
 
 import struct
@@ -44,6 +45,15 @@ KISS_TFESC = 0xDD  # If after an escape, means there was an 0xDB in the source m
 # If it's the final address in the header, set the low bit to 1
 # Ignoring command/response for simple example
 def encode_address(s, final):
+
+    encoded_ssid = 0b00000000
+
+    # First we check if the call has the 'has_been_repeated' asterix at the ended.
+    # If so, set the 'has_been_repeated' flag and remove the asterix
+    if s[-1] == 42:
+        s = s[:-1]
+        encoded_ssid |= 0b10000000
+
     if b"-" not in s:
         s = s + b"-0"  # default to SSID 0
     call, ssid = s.split(b'-')
@@ -51,19 +61,6 @@ def encode_address(s, final):
         call = call + b" "*(6 - len(call)) # pad with spaces
     encoded_call = [x << 1 for x in call[0:6]]
     
-    encoded_ssid = 0b00000000
-    # If ssid ends with *, the message has been repeated, so we have to set the 'has_been_repeated' flag and remove the * from the ssid
-    if ssid[-1] == 42:
-        # print("Message has been repeated")
-        ssid = ssid[:-1]
-        encoded_ssid |= 0b10000000
-    
-    # If SSID was not pressent (and we added the default -0 to it), the has_been_repeated flag could be at the end of the call, so check that as well
-    # Also, there is a lot of bad software around (including this code) and ignorance of the specifications (are there any specs for LoRa APRS?), so always check for the has_been_repeated flag
-    if call[-1] == 42:
-        call = call[:-1]
-        encoded_ssid |= 0b10000000
-    
     # SSID should now be one or two postions long and contain a number (idealy between 0 and 15).
     if len(ssid) == 1 and ssid[0] > 47 and ssid[0] < 58:
         encoded_ssid |= (int(ssid) << 1) | 0b01100000 | (0b00000001 if final else 0)
@@ -194,6 +191,9 @@ def decode_kiss(frame):
         # print("RPT: ", rpt_addr)
         pos += 7
         result += b"," + rpt_addr.strip()
+        # Add repeater flag if set
+        if (rpt_hrr & 0x04) == 0x04:
+            result += b"*"
 
     result += b":"
 

README.md

@@ -1,14 +1,34 @@
 # Raspberry Pi LoRa KISS TNC
 
+This project adds LoRa APRS to the Raspberry Pi. It is fully integrated in the Linux AX.25 stack for maximum flexibility.
+
 This project was originally started by Tom Kottek (https://github.com/tomelec/RPi-LoRa-KISS-TNC). Because the program had some problems dealing with digipeated frames (it crashed when receiving a ssid with the 'has_been_digipeated' flag -*- set), I took on the task of fixing the code for my personal use.
 
+The software is stable and can handle repeated frames (incomming and outgoing) so it can be used with the aprx software to make a digipeater.
+
 ## Software
 
 The software controls the LoRa transceiver connected to the Raspberry´s SPI bus and emulates a KISS TNC over TCP. That makes it possible to use existing software like APRX. It is also possible to attach the KISS interface to the AX.25 stack via socat/kissattach.
 
+Assuming you installed and configured the AX.25 stack, start the LoRa KISS TNC with these commands:
+
+    #!/bin/bash
+
+    # Start TNC software
+    /usr/bin/python3 ~/RPi-LoRa-KISS-TNC/Start_lora-tnc.py &
+    sleep 10
+    # Attach TCP socket to virtual tty device located at /tmp/lorakisstnc
+    sudo /usr/bin/socat PTY,raw,echo=0,link=/tmp/lorakisstnc TCP4:127.0.0.1:10001 &
+    sleep 3
+    # Attach virtual tty to AX.25 stack (port ax2)
+    sudo /usr/sbin/kissattach /tmp/lorakisstnc ax2 &
+
 ## Hardware
 
+[![How to connect LoRa module to Raspberry Pi](./images/RPi_LoRa_shield.svg)](./images/RPi_LoRa_shield.svg)
+
 I also designed my own (open source) hardware for it: a board holding a Raspberry Pi Zero 2 W, an SX1278 LoRa transceiver and a power supply with on/off button to safely switch on and off the system. The design files can be found on my website: [RPi LoRa_shield](https://meezenest.nl/mees/RPi_LoRa_shield.html)
 
 ### To Do
+
 * Add raw TCP KISS socket for true AX.25 over KISS