Move IP address resolution from ipaserver.install.installutils to ipapython.dnsutil

This is to make it reusable from other modules and to avoid future code
duplication.

https://fedorahosted.org/freeipa/ticket/5710

Reviewed-By: Martin Basti <mbasti@redhat.com>

ipapython/dnsutil.py

@@ -24,6 +24,9 @@ import copy
 
 import six
 
+from ipapython.ipautil import CheckedIPAddress
+from ipapython.ipa_log_manager import root_logger
+
 if six.PY3:
     unicode = str
 
@@ -231,6 +234,62 @@ def inside_auto_empty_zone(name):
     return False
 
 
+def resolve_rrsets(fqdn, rdtypes):
+    """
+    Get Resource Record sets for given FQDN.
+    CNAME chain is followed during resolution
+    but CNAMEs are not returned in the resulting rrset.
+
+    :returns:
+        set of dns.rrset.RRset objects, can be empty
+        if the FQDN does not exist or if none of rrtypes exist
+    """
+    # empty set of rdtypes would always return empty set of rrsets
+    assert rdtypes, "rdtypes must not be empty"
+
+    if not isinstance(fqdn, DNSName):
+        fqdn = DNSName(fqdn)
+
+    fqdn = fqdn.make_absolute()
+    rrsets = set()
+    for rdtype in rdtypes:
+        try:
+            answer = dns.resolver.query(fqdn, rdtype)
+            root_logger.debug('found %d %s records for %s: %s',
+                              len(answer), rdtype, fqdn, ' '.join(
+                                  str(rr) for rr in answer))
+            rrsets.add(answer.rrset)
+        except dns.resolver.NXDOMAIN as ex:
+            root_logger.debug(ex)
+            break  # no such FQDN, do not iterate
+        except dns.resolver.NoAnswer as ex:
+            root_logger.debug(ex)  # record type does not exist for given FQDN
+        except dns.exception.DNSException as ex:
+            root_logger.error('DNS query for %s %s failed: %s',
+                              fqdn, rdtype, ex)
+            raise
+
+    return rrsets
+
+
+def resolve_ip_addresses(fqdn):
+    """Get IP addresses from DNS A/AAAA records for given host.
+    :returns:
+        list of IP addresses as CheckedIPAddress objects
+    """
+    rrsets = resolve_rrsets(fqdn, ['A', 'AAAA'])
+    ip_addresses = set()
+    for rrset in rrsets:
+        ip_addresses.update({CheckedIPAddress(ip,  # accept whatever is in DNS
+                                              parse_netmask=False,
+                                              allow_network=True,
+                                              allow_loopback=True,
+                                              allow_broadcast=True,
+                                              allow_multicast=True)
+                             for ip in rrset})
+    return ip_addresses
+
+
 def check_zone_overlap(zone, raise_on_error=True):
     root_logger.info("Checking DNS domain %s, please wait ..." % zone)
     if not isinstance(zone, DNSName):

ipaserver/install/bindinstance.py

@@ -908,7 +908,9 @@ class BindInstance(service.Service):
             if fqdn == self.fqdn:
                 continue
 
-            addrs = installutils.resolve_host(fqdn)
+            addrs = dnsutil.resolve_ip_addresses(fqdn)
+            # hack, will go away with locations
+            addrs = [str(addr) for addr in addrs]
 
             root_logger.debug("Adding DNS records for master %s" % fqdn)
             self.__add_master_records(fqdn, addrs)
@@ -964,7 +966,9 @@ class BindInstance(service.Service):
                 if dns_zone_exists(zone, self.api):
                     addrs = get_fwd_rr(zone, host, api=self.api)
                 else:
-                    addrs = installutils.resolve_host(fqdn)
+                    addrs = dnsutil.resolve_ip_addresses(fqdn)
+                    # hack, will go away with locations
+                    addrs = [str(addr) for addr in addrs]
 
                 self.__add_ipa_ca_records(fqdn, addrs, True)
 
@@ -1084,7 +1088,9 @@ class BindInstance(service.Service):
         if dns_zone_exists(zone, self.api):
             addrs = get_fwd_rr(zone, host, api=self.api)
         else:
-            addrs = installutils.resolve_host(fqdn)
+            addrs = dnsutil.resolve_ip_addresses(fqdn)
+            # hack, will go away with locations
+            addrs = [str(addr) for addr in addrs]
 
         self.domain = domain_name
 
@@ -1172,7 +1178,9 @@ class BindInstance(service.Service):
         if dns_zone_exists(zone, self.api):
             addrs = get_fwd_rr(zone, host, api=self.api)
         else:
-            addrs = installutils.resolve_host(fqdn)
+            addrs = dnsutil.resolve_ip_addresses(fqdn)
+            # hack, will go away with locations
+            addrs = [str(addr) for addr in addrs]
 
         for addr in addrs:
             del_fwd_rr(domain_name, IPA_CA_RECORD, addr, api=self.api)

ipaserver/install/installutils.py

@@ -55,6 +55,7 @@ from ipaserver.install import certs, service, sysupgrade
 from ipaplatform import services
 from ipaplatform.paths import paths
 from ipaplatform.tasks import tasks
+from ipapython import dnsutil
 
 if six.PY3:
     unicode = str
@@ -444,24 +445,6 @@ def create_keytab(path, principal):
 
     kadmin("ktadd -k " + path + " " + principal)
 
-def resolve_host(host_name):
-    try:
-        addrinfos = socket.getaddrinfo(host_name, None,
-                                       socket.AF_UNSPEC, socket.SOCK_STREAM)
-
-        ip_list = []
-
-        for ai in addrinfos:
-            ip = ai[4][0]
-            if ip == "127.0.0.1" or ip == "::1":
-                raise HostnameLocalhost("The hostname resolves to the localhost address")
-
-            ip_list.append(ip)
-
-        return ip_list
-    except socket.error:
-        return []
-
 def get_host_name(no_host_dns):
     """
     Get the current FQDN from the socket and verify that it is valid.
@@ -477,9 +460,10 @@ def get_host_name(no_host_dns):
 
 def get_server_ip_address(host_name, unattended, setup_dns, ip_addresses):
     # Check we have a public IP that is associated with the hostname
-    try:
-        hostaddr = resolve_host(host_name)
-    except HostnameLocalhost:
+    hostaddr = dnsutil.resolve_ip_addresses(host_name)
+    if hostaddr.intersection(
+            {ipautil.CheckedIPAddress(ip, allow_loopback=True)
+             for ip in ['127.0.0.1', '::1']}):
         print("The hostname resolves to the localhost address (127.0.0.1/::1)", file=sys.stderr)
         print("Please change your /etc/hosts file so that the hostname", file=sys.stderr)
         print("resolves to the ip address of your network interface.", file=sys.stderr)