Add EthernetBridge: UDP mesh packet tunneling over Ethernet#1
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rfb wants to merge 1 commit intorgregg:rak-ethernetfrom
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Add EthernetBridge: UDP mesh packet tunneling over Ethernet#1rfb wants to merge 1 commit intorgregg:rak-ethernetfrom
rfb wants to merge 1 commit intorgregg:rak-ethernetfrom
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Introduces EthernetBridge, a new bridge implementation that transports
mesh packets over UDP datagrams. Follows the same BridgeBase pattern as
RS232Bridge and ESPNowBridge, using identical wire framing (magic header,
length, Fletcher-16 checksum) for cross-bridge compatibility.
Features:
- Broadcast mode (default): forwards packets to 255.255.255.255 for
passive network analysis / monitor mode
- Unicast mode: set ETHERNET_BRIDGE_DEST_IP to bridge two ethernet-
enabled nodes together over IP
- Bidirectional: listens on the same UDP port for packet injection back
into the mesh
- Enabled via WITH_ETHERNET_BRIDGE build flag; port defaults to 5005
Changes:
- src/helpers/bridges/EthernetBridge.h/.cpp — new bridge class
- src/helpers/CommonCLI.h — add WITH_ETHERNET_BRIDGE to WITH_BRIDGE guard
- examples/simple_repeater/MyMesh.h/.cpp — wire in EthernetBridge
- variants/rak4631/platformio.ini — enable bridge in RAK_4631_repeater_ethernet env
- tools/bridge_monitor.py — Python UDP monitor that decodes mesh packets,
including group channel decryption (AES128-ECB + HMAC-SHA256)
---
Setting up a RAK4631 repeater in monitor mode
1. Build and flash
In variants/rak4631/platformio.ini the RAK_4631_repeater_ethernet environment already has WITH_ETHERNET_BRIDGE
enabled. Flash it:
pio run -e RAK_4631_repeater_ethernet --target upload
2. Configure the repeater via serial or telnet
Once booted, connect on serial (pio device monitor) or telnet to port 23, then:
# Forward every packet the repeater hears (not just ones it sends)
set bridge.source rx
# Confirm it's running
get bridge.enabled → on
get bridge.source → logRx
These settings persist across reboots.
3. Run the monitor on your workstation
# Install optional dependency for channel decryption
pip install pycryptodome
# Basic — shows all packet types, group messages shown as encrypted
python3 tools/bridge_monitor.py
# With Public channel decryption
python3 tools/bridge_monitor.py \
--channel "Public:8b3387e9c5cdea6ac9e5edbaa115cd72"
# With a custom private channel (get the secret from the companion app export)
python3 tools/bridge_monitor.py \
--channel "Public:8b3387e9c5cdea6ac9e5edbaa115cd72" \
--channel "MyTeam:<your-64-char-hex-secret>"
# Show raw hex dump of every packet
python3 tools/bridge_monitor.py --hex
4. Example output
[21:12:20.568] 192.168.88.170
Type: ADVERT (FLOOD, ver=0)
Node: Alice's Node [chat]
ID: 8b3387... (pub_key prefix)
Time: 2025-03-24 21:12:18 UTC
[21:12:45.101] 192.168.88.170
Type: GRP_TXT (FLOOD, ver=0)
Channel: Public (0x11)
Time: 21:12:43 UTC
Message: Alice: anyone on?
Notes
- The bridge uses UDP broadcast by default — the monitor just needs to be on the same LAN segment, no IP
configuration required.
- For bridging two nodes together instead of monitoring, set ETHERNET_BRIDGE_DEST_IP in the build flags to the
peer node's IP on both devices.
- bridge.source rx captures everything the repeater hears. bridge.source tx (the default) only forwards packets
the node itself transmitted.
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Hi Ryan - Just wanted to share this with you. My goal here is to bridge to remote repeaters.. I know - not in the spirit of meshcore, but I live in an isolated location and I want to connect to a friend's isolated mesh so we can share messages...
I don't imagine you'll pull this - Just wanted to share what I built off your work.