X-Git-Url: http://xvm.mit.edu/gitweb/invirt/packages/invirt-dns.git/blobdiff_plain/56cffcd902204e35cc28915efb27eea559a6618d..50039d25b73ab7fe80d17407602e1e0b1082f24e:/invirt-dns diff --git a/invirt-dns b/invirt-dns index d5fa021..188d1ce 100755 --- a/invirt-dns +++ b/invirt-dns @@ -4,16 +4,19 @@ 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 from invirt.common import InvirtConfigError from invirt.config import structs as config import invirt.database +from invirt.database import NIC import psycopg2 import sqlalchemy import time import re +import sys class DatabaseAuthority(common.ResolverBase): """An Authority that is loaded from a file.""" @@ -45,7 +48,7 @@ class DatabaseAuthority(common.ResolverBase): for i in range(3): try: value = self._lookup_unsafe(name, cls, type, timeout = None) - except (psycopg2.OperationalError, sqlalchemy.exceptions.SQLError): + except (psycopg2.OperationalError, sqlalchemy.exceptions.DBAPIError): if i == 2: raise print "Reloading database" @@ -93,10 +96,12 @@ class DatabaseAuthority(common.ResolverBase): if name.endswith(".in-addr.arpa"): if type in (dns.PTR, dns.ALL_RECORDS): ip = '.'.join(reversed(name.split('.')[:-2])) - value = invirt.database.NIC.query.filter_by(ip=ip).first() + value = invirt.database.NIC.query.filter((NIC.ip == ip) | (NIC.other_ip == ip)).first() if value and value.hostname: hostname = value.hostname if '.' not in hostname: + if ip == value.other_ip: + hostname = hostname + ".other" hostname = hostname + "." + config.dns.domains[0] record = dns.Record_PTR(hostname, ttl) results.append(dns.RRHeader(name, dns.PTR, dns.IN, @@ -108,7 +113,7 @@ class DatabaseAuthority(common.ResolverBase): ttl, self.soa, auth=True)) # FIXME: Should only return success with no records if the name actually exists - elif name == domain or name == '.'+domain: + elif name == domain or name == '.'+domain or name == 'other.'+domain: if type in (dns.A, dns.ALL_RECORDS): record = dns.Record_A(config.dns.nameservers[0].ip, ttl) results.append(dns.RRHeader(name, dns.A, dns.IN, @@ -123,13 +128,25 @@ class DatabaseAuthority(common.ResolverBase): else: host = name[:-len(domain)-1] + other = False + if host.endswith(".other"): + host = host[:-len(".other")] + other = True value = invirt.database.NIC.query.filter_by(hostname=host).first() if value: - ip = value.ip + if other: + ip = value.other_ip + action = value.other_action + else: + ip = value.ip else: - value = invirt.database.Machine.query().filter_by(name=host).first() + value = invirt.database.Machine.query.filter_by(name=host).first() if value: - ip = value.nics[0].ip + if other: + ip = value.nics[0].other_ip + action = value.nics[0].other_action + else: + ip = value.nics[0].ip else: return defer.fail(failure.Failure(dns.AuthoritativeDomainError(name))) if ip is None: @@ -138,7 +155,11 @@ class DatabaseAuthority(common.ResolverBase): record = dns.Record_A(ip, ttl) results.append(dns.RRHeader(name, dns.A, dns.IN, ttl, record, auth=True)) - elif type == dns.SOA: + if other and type in (dns.TXT, dns.ALL_RECORDS): + record = dns.Record_TXT(action if action else '', ttl=ttl) + results.append(dns.RRHeader(name, dns.TXT, dns.IN, + ttl, record, auth=True)) + if type == dns.SOA: results.append(dns.RRHeader(domain, dns.SOA, dns.IN, ttl, self.soa, auth=True)) @@ -147,9 +168,9 @@ class DatabaseAuthority(common.ResolverBase): additional = [] return defer.succeed((results, authority, additional)) -class QuotingBindAuthority(authority.BindAuthority): +class DelegatingQuotingBindAuthority(authority.BindAuthority): """ - A BindAuthority that (almost) deals with quoting correctly + A delegating BindAuthority that (almost) deals with quoting correctly This will catch double quotes as marking the start or end of a quoted phrase, unless the double quote is escaped by a backslash @@ -194,14 +215,68 @@ class QuotingBindAuthority(authority.BindAuthority): L.append(split_line) return filter(None, L) + # See https://twistedmatrix.com/documents/13.1.0/api/twisted.internet.defer.html#inlineCallbacks + @defer.inlineCallbacks + def _lookup(self, name, cls, type, timeout = None): + try: + result = yield authority.BindAuthority._lookup(self, name, cls, + type, timeout) + defer.returnValue(result) + except Exception as e: + # XXX: Twisted returns DomainError even if it is + # authoritative for the domain because our SOA record + # incorrectly contains (origin + "." + origin) + if not isinstance(e, (dns.DomainError, dns.AuthoritativeDomainError)): + sys.stderr.write("while looking up '%s', got: %s\n" % (name, e)) + + # If we didn't find an exact match for the name we were + # seeking, check if it's within a subdomain we're supposed + # to delegate to some other DNS server. + while '.' in name: + _, name = name.split('.', 1) + try: + # BindAuthority puts the NS in the authority + # section automatically for us, so just return + # it. We override the type to NS. + result = yield authority.BindAuthority._lookup(self, name, cls, + dns.NS, timeout) + defer.returnValue(result) + except Exception: # Should be one of (dns.DomainError, dns.AuthoritativeDomainError) + pass + # We didn't find a delegation, so return the original + # NXDOMAIN. + raise + +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 + return defer.succeed(([], [], [])) + if '__main__' == __name__: resolvers = [] try: for zone in config.dns.zone_files: for origin in config.dns.domains: - r = QuotingBindAuthority(zone) + r = DelegatingQuotingBindAuthority(zone) # This sucks, but if I want a generic zone file, I have to # reload the information by hand + # XXX: This causes our SOA record to contain + # (origin + "." + origin) + # As a result the resolver never believes it is authoritative. r.origin = origin lines = open(zone).readlines() lines = r.collapseContinuations(r.stripComments(lines)) @@ -214,7 +289,8 @@ 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