Bind + ISC dhcpd integration (for intranet split-horizon, etc)

[Philip Prindeville]

Heads up that there’s a major change to the PR:

https://github.com/openwrt/packages/pull/14240

It adds support for “cname”, “domain”, “mxhost”, and “srvhost” config sections.  Thanks to Bjorn for pointing me at how to use nsupdate to do this.

Calling out run-time requirements on “named” and “nsupdate” in the dependencies.

Still trying to work through a start/boot problem where Bind doesn’t seem to listen on all interfaces (what’s surprising is that these aren’t even DHCP’d interfaces… even “wan” has a static address assigned).

If anyone has any suggestions on how to troubleshoot this, please speak up.

Looking at lib/ns/interfacemgr.c, it seems that Bind detects RTM_NEWADDR and RTM_DELADDR messages from Netlink so no external prodding should be required to handle interface changes.

(Though I don’t see RTM_NEWLINK in the source code… but maybe just catching addresses is enough; I’ve not dug very deep there.)