`automatic-interface-scan no` does not prevent routing socket usage

Summary

Configuration automatic-interface-scan no; still opens routing socket and processes routing messages - and then drops the results. I think we should not start listening on routing sockets at all. It makes my testing harder that it needs to be.

BIND version affected

• Affects v9.19: 67b95109
• Affects v9.18: 7f81d5eb
• Older versions were not tested albeit I believe that it also Affects v9.16.

Steps to reproduce

1. use options { automatic-interface-scan no; };
2. named -g -c named.conf -d 99
3. Observe that routing messages are still received and processed

What is the current bug behavior?

Routing messages are listened to and processed.

This makes named testing more noisy because there is one more variable at play, and I have no control over routing messages. Don't even look at strace, it's even bigger mess than debug log.

It seems that call sites to ns_interfacemgr_create() have hardcoded parameter scan to true. IMHO this parameter should be taken from named.conf automatic-interface-scan statement.

What is the expected correct behavior?

Routing messages are not received/subscribed to at all.

Relevant logs

On a system - doing nothing - this gets logged quite often.

05-Jun-2024 10:26:52.712 route_recv: success
05-Jun-2024 10:26:52.729 route_recv: success
05-Jun-2024 10:26:56.715 route_recv: success
05-Jun-2024 10:26:56.825 route_recv: success

Log from commit 67b95109.