From be712d887af49474116185bb38bb2afce6527173 Mon Sep 17 00:00:00 2001 From: Mitchell E Berger Date: Sat, 4 Oct 2014 14:19:20 -0400 Subject: [PATCH 1/1] Be tolerant of requests for unimplemented record types. Fixes: Anders's home router Resolves: LP#1376373 --- debian/changelog | 9 +++++++++ invirt-dns | 24 +++++++++++++++++++++++- 2 files changed, 32 insertions(+), 1 deletion(-) diff --git a/debian/changelog b/debian/changelog index 1e721c4..5615a20 100644 --- a/debian/changelog +++ b/debian/changelog @@ -1,3 +1,12 @@ +invirt-dns (0.0.16) precise; urgency=low + + * Be tolerant of requests for record types that have not been + implemented by Twisted yet - instead of returning SERVFAIL, + return either NXDOMAIN or an empty result set with NOERROR + as appropriate depending on whether the name exists in our zones. + + -- Mitchell Berger Sat, 04 Oct 2014 14:10:00 - 0400 + invirt-dns (0.0.15) precise; urgency=low * Updating version for precise migration. diff --git a/invirt-dns b/invirt-dns index c320e51..8cd8337 100755 --- a/invirt-dns +++ b/invirt-dns @@ -4,6 +4,7 @@ from twisted.names import server from twisted.names import dns from twisted.names import common from twisted.names import authority +from twisted.names import resolve from twisted.internet import defer from twisted.python import failure @@ -220,6 +221,26 @@ class DelegatingQuotingBindAuthority(authority.BindAuthority): deferredResult = defer.succeed(([], nsResults, nsAdditional)) return deferredResult +class TypeLenientResolverChain(resolve.ResolverChain): + """ + This is a ResolverChain which is more lenient in its handling of + queries requesting unimplemented record types. + """ + + def query(self, query, timeout = None): + try: + return self.typeToMethod[query.type](str(query.name), timeout) + except KeyError, e: + # We don't support the requested record type. Twisted would + # have us return SERVFAIL. Instead, we'll check whether the + # name exists in our zone at all and return NXDOMAIN or an empty + # result set with NOERROR as appropriate. + deferredResult = self.lookupAllRecords(str(query.name), timeout) + if isinstance(deferredResult.result, failure.Failure): + return deferredResult + (results, authority, additional) = deferredResult.result + return defer.succeed(([], authority, additional)) + if '__main__' == __name__: resolvers = [] try: @@ -240,7 +261,8 @@ if '__main__' == __name__: resolvers.append(DatabaseAuthority()) verbosity = 0 - f = server.DNSServerFactory(authorities=resolvers, verbose=verbosity) + f = server.DNSServerFactory(verbose=verbosity) + f.resolver = TypeLenientResolverChain(resolvers) p = dns.DNSDatagramProtocol(f) f.noisy = p.noisy = verbosity -- 1.7.9.5