Feature Request: Include the related address:port in a warning/warnings

[drjaska]

Hey, I have used software which is built on top of librespot and thus also uses this library. Thank you for your amazing work but recently I have been frustrated with the lack of information in logged messages when debugging networking issues.

[WARN libmdns::fsm] error sending packet Os { code: 99, kind: AddrNotAvailable, message: "Cannot assign requested address" }

Could this message please include the information about the requested port? Was it TCP or UDP? At the very least what address:port combination was requested but not assignable? This information would help debugging related issues a lot, cheers.

I am unaware if other messages could and should receive similar improvements.

[willstott101]

That sounds reasonable. It would definitely be helpful if we could see the iface and address and such.

FYI mdns uses only UDP, much of the communication is over multicast at the addresses here. We attempt to join UDP multicast for every non-loopback interface on both ipv4 and ipv6 at the standard mdns address. I believe it is relatively common for some networks to limit/prevent multicast communication, and we have seen issues in the past with libmdns detecting non-loopback but virtual network interfaces like docker ones and such - which may not always make sense to broadcast on.