Add dns_discovery_domain option

The service discovery used to use the SSSD domain name to perform DNS
queries. This is not an optimal solution, for example from the point of
view of authconfig.

This patch introduces a new option "dns_discovery_domain" that allows to set
the domain part of a DNS SRV query. If this option is not set, the
default behavior is to use the domain part of the machine's hostname.

Fixes: #479

4 files changed, 29 insertions, 1 deletions

diff --git a/src/config/SSSDConfig.py b/src/config/SSSDConfig.py
index f1ff02aa..22013eeb 100644
--- a/src/config/SSSDConfig.py
+++ b/src/config/SSSDConfig.py
@@ -82,6 +82,7 @@ option_strings = {
     'lookup_family_order' : _('Restrict or prefer a specific address family when performing DNS lookups'),
     'account_cache_expiration' : _('How long to keep cached entries after last successful login (days)'),
     'dns_resolver_timeout' : _('How long to wait for replies from DNS when resolving servers (seconds)'),
+    'dns_discovery_domain' : _('The domain part of service discovery DNS query'),
 
     # [provider/ipa]
     'ipa_domain' : _('IPA domain'),
diff --git a/src/config/SSSDConfigTest.py b/src/config/SSSDConfigTest.py
index 63d1ad11..e99a7876 100755
--- a/src/config/SSSDConfigTest.py
+++ b/src/config/SSSDConfigTest.py
@@ -478,6 +478,7 @@ class SSSDConfigTestSSSDDomain(unittest.TestCase):
             'lookup_family_order',
             'account_cache_expiration',
             'dns_resolver_timeout',
+            'dns_discovery_domain',
             'id_provider',
             'auth_provider',
             'access_provider',
@@ -795,6 +796,7 @@ class SSSDConfigTestSSSDDomain(unittest.TestCase):
             'account_cache_expiration',
             'lookup_family_order',
             'dns_resolver_timeout',
+            'dns_discovery_domain',
             'id_provider',
             'auth_provider',
             'access_provider',
diff --git a/src/config/etc/sssd.api.conf b/src/config/etc/sssd.api.conf
index f0ef4114..ca85ed70 100644
--- a/src/config/etc/sssd.api.conf
+++ b/src/config/etc/sssd.api.conf
@@ -59,6 +59,7 @@ account_cache_expiration = int, None, false
 filter_users = list, str, false
 filter_groups = list, str, false
 dns_resolver_timeout = int, None, false
+dns_discovery_domain = str, None, false
 
 # Special providers
 [provider/permit]
diff --git a/src/config/upgrade_config.py b/src/config/upgrade_config.py
index d47fcd38..ff22b489 100644
--- a/src/config/upgrade_config.py
+++ b/src/config/upgrade_config.py
@@ -59,6 +59,28 @@ class SSSDConfigFile(SSSDChangeConf):
             if item:
                 item['name'] = new_name
 
+    def _add_dns_domain_name(self, domain):
+        id_provider = self.findOpts(domain['value'], 'option', 'id_provider')[1]
+        dns_domain_name = { 'type' : 'option',
+                            'name' : 'dns_discovery_domain',
+                            'value' : domain['name'].lstrip('domain/') }
+        if id_provider['value'] == 'ldap':
+            server = self.findOpts(domain['value'], 'option', 'ldap_uri')[1]
+            if not server or "__srv__" in server['value']:
+                domain['value'].insert(0, dns_domain_name)
+                return
+        elif id_provider['value'] == 'ipa':
+            server = self.findOpts(domain['value'], 'option', 'ipa_server')[1]
+            if not server or "__srv__" in server['value']:
+                domain['value'].insert(0, dns_domain_name)
+                return
+
+        auth_provider = self.findOpts(domain['value'], 'option', 'auth_provider')[1]
+        if auth_provider and auth_provider['value'] == 'krb5':
+            server = self.findOpts(domain['value'], 'option', 'krb5_kdcip')[1]
+            if not server or "__srv__" in server['value']:
+                domain['value'].insert(0, dns_domain_name)
+
     def _do_v2_changes(self):
         # remove Data Provider
         srvlist = self.get_option_index('sssd', 'services')[1]
@@ -69,9 +91,11 @@ class SSSDConfigFile(SSSDChangeConf):
             srvlist['value'] = ", ".join([srv for srv in services])
         self.delete_option('section', 'dp')
 
-        # remove magic_private_groups from all domains
         for domain in [ s for s in self.sections() if s['name'].startswith("domain/") ]:
+            # remove magic_private_groups from all domains
             self.delete_option_subtree(domain['value'], 'option', 'magic_private_groups')
+            # check if we need to add dns_domain
+            self._add_dns_domain_name(domain)
 
     def _update_option(self, to_section_name, from_section_name, opts):
         to_section = [ s for s in self.sections() if s['name'].strip() == to_section_name ]