dns: implement updating the master server

nsupdate/main/_tests/test_dnstools.py

@@ -4,13 +4,14 @@ Tests for dnstools module.
 
 import pytest
 
-from nsupdate.main.dnstools import (query_ns, NONEXISTING_HOST, WWW_HOST, WWW_IPV4_HOST, WWW_IPV4_IP,
+from nsupdate.main.dnstools import (query_ns, parse_name, update_ns,
+                                    BASEDOMAIN, NONEXISTING_HOST, WWW_HOST, WWW_IPV4_HOST, WWW_IPV4_IP,
                                     WWW_IPV6_HOST, WWW_IPV6_IP, )
 
 from dns.resolver import NXDOMAIN
 
 
-class Tests(object):
+class TestQuery(object):
     def test_queries_ok(self):
         """
         check some simple dns lookups
@@ -25,3 +26,87 @@ class Tests(object):
             query_ns(NONEXISTING_HOST, 'A')
         with pytest.raises(NXDOMAIN):
             query_ns(NONEXISTING_HOST, 'AAAA')
+
+
+class TestUpdate(object):
+    def test_parse1(self):
+        """
+        check fqdn parsing
+        """
+        origin, relname = parse_name('foo.' + BASEDOMAIN)
+        assert str(origin) == BASEDOMAIN + '.'
+        assert str(relname) == 'foo'
+
+    def test_parse2(self):
+        origin, relname = parse_name('foo.bar.' + BASEDOMAIN)
+        assert str(origin) == BASEDOMAIN + '.'
+        assert str(relname) == 'foo.bar'
+
+    def test_parse_with_origin(self):
+        origin, relname = parse_name('foo.bar.baz.org', 'bar.baz.org')
+        assert str(origin) == 'bar.baz.org' + '.'
+        assert str(relname) == 'foo'
+
+    def test_add_del_v4(self):
+        host, ip = 'test1.' + BASEDOMAIN, '1.1.1.1'
+        response = update_ns(host, 'A', ip, action='add', ttl=60)
+        print response
+        assert query_ns(host, 'A') == ip
+        response = update_ns(host, 'A', action='del')
+        print response
+        with pytest.raises(NXDOMAIN):
+            query_ns(host, 'A') == ip
+
+    def test_update_v4(self):
+        host, ip = 'test2.' + BASEDOMAIN, '2.2.2.2'
+        response = update_ns(host, 'A', ip, action='upd', ttl=60)
+        print response
+        assert query_ns(host, 'A') == ip
+
+        host, ip = 'test2.' + BASEDOMAIN, '3.3.3.3'
+        response = update_ns(host, 'A', ip, action='upd', ttl=60)
+        print response
+        assert query_ns(host, 'A') == ip
+
+    def test_add_del_v6(self):
+        host, ip = 'test3.' + BASEDOMAIN, '::1'
+        response = update_ns(host, 'AAAA', ip, action='add', ttl=60)
+        print response
+        assert query_ns(host, 'AAAA') == ip
+        response = update_ns(host, 'AAAA', action='del')
+        print response
+        with pytest.raises(NXDOMAIN):
+            query_ns(host, 'AAAA') == ip
+
+    def test_update_v6(self):
+        host, ip = 'test4.' + BASEDOMAIN, '::2'
+        response = update_ns(host, 'AAAA', ip, action='upd', ttl=60)
+        print response
+        assert query_ns(host, 'AAAA') == ip
+
+        host, ip = 'test4.' + BASEDOMAIN, '::3'
+        response = update_ns(host, 'AAAA', ip, action='upd', ttl=60)
+        print response
+        assert query_ns(host, 'AAAA') == ip
+
+    def test_update_mixed(self):
+        host4, ip4 = 'test5.' + BASEDOMAIN, '4.4.4.4'
+        response = update_ns(host4, 'A', ip4, action='upd', ttl=60)
+        print response
+        assert query_ns(host4, 'A') == ip4
+
+        host6, ip6 = 'test5.' + BASEDOMAIN, '::4'
+        response = update_ns(host6, 'AAAA', ip6, action='upd', ttl=60)
+        print response
+        assert query_ns(host6, 'AAAA') == ip6
+
+        # make sure the v4 is unchanged
+        assert query_ns(host4, 'A') == ip4
+
+        host4, ip4 = 'test5.' + BASEDOMAIN, '5.5.5.5'
+        response = update_ns(host4, 'A', ip4, action='upd', ttl=60)
+        print response
+        assert query_ns(host4, 'A') == ip4
+
+        # make sure the v6 is unchanged
+        assert query_ns(host6, 'AAAA') == ip6

nsupdate/main/dnstools.py

@@ -2,6 +2,14 @@
 Misc. DNS related code: query, dynamic update, etc.
 """
 
+import dns.name
+import dns.resolver
+import dns.query
+import dns.update
+import dns.tsig
+import dns.tsigkeyring
+
+
 SERVER = '85.10.192.104'  # ns1.thinkmo.de (master / dynamic upd server for nsupdate.info)
 BASEDOMAIN = 'nsupdate.info'
 
@@ -12,8 +20,9 @@ WWW_IPV6_HOST = 'www.ipv6.' + BASEDOMAIN
 WWW_IPV4_IP = '178.32.221.14'
 WWW_IPV6_IP = '2001:41d0:8:e00e::1'
 
-import dns.name
-import dns.resolver
+UPDATE_ALGO = dns.tsig.HMAC_SHA512
+UPDATE_KEY = 'YWFhYWFhYWFhYWFhYWFhYWFhYWFhYWFhYWFhYWFhYWFhYWFhYWFhYWFhYWFhYWFhYWFhYWFhYWFhYWFhYWFhYQ=='
+
 
 def query_ns(qname, rdtype):
     """
@@ -32,3 +41,48 @@ def query_ns(qname, rdtype):
     resolver.search = [dns.name.from_text(BASEDOMAIN), ]
     answer = resolver.query(qname, rdtype)
     return str(list(answer)[0])
+
+
+def parse_name(fqdn, origin=None):
+    """
+    Parse a fully qualified domain name into a relative name
+    and a origin zone. Please note that the origin return value will
+    have a trailing dot.
+
+    :param fqdn: fully qualified domain name (str)
+    :param origin: origin zone (optional, str)
+    :return: origin, relative name (both dns.name.Name)
+    """
+    fqdn = dns.name.from_text(fqdn)
+    if origin is None:
+        origin = dns.resolver.zone_for_name(fqdn)
+        rel_name = fqdn.relativize(origin)
+    else:
+        origin = dns.name.from_text(origin)
+        rel_name = fqdn - origin
+    return origin, rel_name
+
+
+def update_ns(fqdn, rdtype='A', ipaddr=None, origin=None, action='upd', ttl=60):
+    """
+    update our master server
+
+    :param qname: the name to update
+    :param rdtype: the record type
+    :param action: 'add', 'del' or 'upd'
+    """
+    assert action in ['add', 'del', 'upd', ]
+    origin, name = parse_name(fqdn, origin)
+    upd = dns.update.Update(origin,
+                            keyring=dns.tsigkeyring.from_text({BASEDOMAIN+'.': UPDATE_KEY}),
+                            keyalgorithm=UPDATE_ALGO)
+    if action == 'add':
+        assert ipaddr is not None
+        upd.add(name, ttl, rdtype, ipaddr)
+    elif action == 'del':
+        upd.delete(name, rdtype)
+    elif action == 'upd':
+        assert ipaddr is not None
+        upd.replace(name, ttl, rdtype, ipaddr)
+    response = dns.query.tcp(upd, SERVER)
+    return response