HostDB and DNS project

what is the situation?

• DNS and HostDB module have some small problmes:

1. TS-313: DNS and resolvers improvements --FIXED
2. TS-435: SplitDNS doesn't work --FIXING
3. TS-?: need a api to set hostdb map data directly
4. TS-492: Allow use of client supplied IP address for origin server. --PATCH on wccp branch

• DNS and HostDB require for enhancement:

1. SplitDNS need to get cleanup, we need to keep SplitDNS under DNS only, not mess up with codes in proxy/http2.
2. DNS codes a little mess, should get more localization, regarding for the old libresolv like codes
3. way to passthrough HostDB cache
4. easy way to setup Origin Source server IP, maybe something like Hosts.
5. need to get a way for DNS and(or) HostDB pluginable, can hooking somewhere.

what are we planning:

1. Fix SplitDNS: TS-435.
2. cleanup SplitDNS: keep SplitDNS under DNS only, not mess up with codes in proxy/http2.
3. make dns more flex:

• way to passthrough HostDB cache
• easy way to setup Origin Source server IP, maybe something like Hosts.
• need to get a way for DNS and(or) HostDB pluginable, can hooking somewhere.

1. cleanup old codes.