Adding upstream version 2:4.20.0+dfsg.upstream/2%4.20.0+dfsg

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 68 insertions, 0 deletions

diff --git a/python/samba/dnsresolver.py b/python/samba/dnsresolver.py
new file mode 100644
index 0000000..a627555
--- /dev/null
+++ b/python/samba/dnsresolver.py
@@ -0,0 +1,68 @@
+# Samba wrapper for DNS resolvers
+#
+# Copyright (C) Stanislav Levin <slev@altlinux.org>
+# Copyright (C) Alexander Bokovoy <ab@samba.org>
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+
+import dns.resolver
+import dns.rdatatype
+import dns.reversename
+
+class DNSResolver(dns.resolver.Resolver):
+    """DNS stub resolver compatible with both dnspython < 2.0.0
+    and dnspython >= 2.0.0.
+
+    Set `use_search_by_default` attribute to `True`, which
+    determines the default for whether the search list configured
+    in the system's resolver configuration is used for relative
+    names, and whether the resolver's domain may be added to relative
+    names.
+
+    Increase the default lifetime which determines the number of seconds
+    to spend trying to get an answer to the question. dnspython 2.0.0
+    changes this to 5sec, while the previous one was 30sec.
+    """
+    def __init__(self, *args, **kwargs):
+        super().__init__(*args, **kwargs)
+        self.reset_defaults()
+        self.resolve = getattr(super(), "resolve", self.query)
+        self.resolve_address = getattr(
+            super(),
+            "resolve_address",
+            self._resolve_address
+        )
+
+    def reset_defaults(self):
+        self.use_search_by_default = True
+        # the default is 5sec
+        self.lifetime = 15
+
+    def reset(self):
+        super().reset()
+        self.reset_defaults()
+
+    def _resolve_address(self, ip_address, *args, **kwargs):
+        """Query nameservers for PTR records.
+
+        :param ip_address: IPv4 or IPv6 address
+        :type ip_address: str
+        """
+        return self.resolve(
+            dns.reversename.from_address(ip_address),
+            rdtype=dns.rdatatype.PTR,
+            *args,
+            **kwargs,
+        )