[lwip-users] UDP routing over IPv6?

[Barnabás Králik]

Hi,

 

I’m trying to send a UDP packet in reply to a host outside the LwIP device’s own /64 subnet, but under the same /48 prefix.

The application is listening on port 9000 without a local IP set as IPs come and go. (It is an nRF52832 w/ lwIP 2.0.2 w/o an OS, communicating over 6LoWPAN-over-BLE)

Sending a packet fails with ERR_RTE (from udp.c:619) as ip6_select_source_address does not have any idea what IP address to use.

I also don’t see any reliable way to recover the destination address in the udp receive callback.

My only idea is to set up separate listeners for all IPs but that is wasteful with resources and defeats the purpose of listening on :: .

 

What would be your solution for the issue? Can this be solved in an elegant way without changing LwIP itself?

 

Thanks

Barnabás