[Feature] Passive Traceroute Observations

[mblauser]

Implement passive observation and adoption of traceroute results initiated by other nodes to significantly reduce network overhead.

Description

Could MeshSense be enhanced to passively monitor traceroute operations initiated by other nodes and MeshSense instances on the local mesh network? Utilizing these responses by others would allow each MeshSense instance to:

• Capture and store routing information discovered by peer nodes
• Update its topology from observed data
• Reset the tracerouteRateLimit timer for each node response observed
• Avoid redundant traceroute requests for recently observed paths

Technical Benefits

• Scalable Efficiency: Network overhead reduction scales linearly with the number of MeshSense instances (n) in the mesh
• Bandwidth Conservation: Dramatically reduces redundant traceroute packets in dense mesh environments
• Improved Battery Life: Fewer transmissions means lower power consumption for all nodes
• Fresher Topology Data: More frequent updates without additional network load

Implementation Considerations

• Stateless listener for traceroute response packets
• Verification mechanism to ensure observed traceroutes are valid before adoption
• Decision logic for nodes identified in traceroutes but not yet self-observed
• Staleness tracking for passively acquired traceroutes
• Possible priority system for self-initiated vs. passively observed traceroutes

This collaborative approach would improve the speed and efficiency of mesh traceroute discovery while maintaining topology accuracy.

[GUVWAF]

I think this is a good idea, but it requires modifications to the Meshtastic firmware. Currently non-broadcast messages not directed to the node are not sent to a client app.