[MaraDNS list] Deadwood 3.1.01 released

[Sam Trenholme]

While everyone else in the USA has been celebrating Thanksgiving (OK,
that's a slight exaggeration...I also have been celebrating
Thanksgiving but made as much time as I could to work on Deadwood), I
have been taking advantage of the days off from my day job to
implement something in Deadwood that I didn't have a chance to
implement before. I would like to thank Nicholas Bamber, again, for
his sponsorship that makes this work possible.

One issue Deadwood 3.0 has had is that it doesn't use cached
incomplete CNAME referrals. Let me explain...

When trying to resolve, say, news.yahoo.com, we end up getting a reply
like this: "news.yahoo.com's name is actually
some-horrible-really-long-name.yahoodns.net, and I am not going to
tell you where to find some-horrible-really-long-name.yahoodns.net".
So, Deadwood has to go to all of the effort to locate this really long
horrible name.

Now, 15 minutes later, once news.yahoo.com has expired from the cache,
let us suppose someone else asks for news.yahoo.com. While Deadwood,
in fact, notes that news.yahoo.com really uses some other name,
Deadwood 3 does not actually use this information and has to start
over to find news.yahoo.com.

Deadwood 3.1.01 fixes all this. Deadwood will now use an incomplete
CNAME record that is in its cache to speed up solving these kinds of
difficult-to-resolve CNAME chains. Since Deadwood has always cached
these records, this change to the code doesn't even change the binary
format for Deadwood's cache file.

Since this required re-factoring quite a bit of Deadwood's recursive
resolver, it was rather difficult to implement. Also, due to the
amount of code rewritten, this is a testing release. Please only use
this release if you are willing to remain subscribed to the MaraDNS
mailing list to report bugs. It can be downloaded here:

    http://www.maradns.org/deadwood/testing/

- Sam