dns: Delete dnsNode objects when they are empty

If an update leaves the dnsNode without any entries, the dnsNode object
should be deleted. Thanks to Günter Kukkukk for his excellent debugging
work on this one.

This should fix bug #9559

Signed-off-by: Kai Blin <kai@samba.org>

Reviewed-by: Andrew Bartlett <abartlet@samba.org>

1 files changed, 117 insertions, 0 deletions

diff --git a/python/samba/tests/dns.py b/python/samba/tests/dns.py
index 15672a0b00..0ac9cf4b8b 100644
--- a/python/samba/tests/dns.py
+++ b/python/samba/tests/dns.py
@@ -534,6 +534,123 @@ class TestDNSUpdates(DNSTest):
         response = self.dns_transaction_udp(p)
         self.assert_dns_rcode_equals(response, dns.DNS_RCODE_NXDOMAIN)
 
+    def test_readd_record(self):
+        "Test if adding, deleting and then readding a records works"
+
+        NAME = "readdrec.%s" % self.get_dns_domain()
+
+        # Create the record
+        p = self.make_name_packet(dns.DNS_OPCODE_UPDATE)
+        updates = []
+
+        name = self.get_dns_domain()
+
+        u = self.make_name_question(name, dns.DNS_QTYPE_SOA, dns.DNS_QCLASS_IN)
+        updates.append(u)
+        self.finish_name_packet(p, updates)
+
+        updates = []
+        r = dns.res_rec()
+        r.name = NAME
+        r.rr_type = dns.DNS_QTYPE_TXT
+        r.rr_class = dns.DNS_QCLASS_IN
+        r.ttl = 900
+        r.length = 0xffff
+        rdata = dns.txt_record()
+        rdata.txt = '"This is a test"'
+        r.rdata = rdata
+        updates.append(r)
+        p.nscount = len(updates)
+        p.nsrecs = updates
+
+        response = self.dns_transaction_udp(p)
+        self.assert_dns_rcode_equals(response, dns.DNS_RCODE_OK)
+
+        # Now check the record is around
+        p = self.make_name_packet(dns.DNS_OPCODE_QUERY)
+        questions = []
+        q = self.make_name_question(NAME, dns.DNS_QTYPE_TXT, dns.DNS_QCLASS_IN)
+        questions.append(q)
+
+        self.finish_name_packet(p, questions)
+        response = self.dns_transaction_udp(p)
+        self.assert_dns_rcode_equals(response, dns.DNS_RCODE_OK)
+
+        # Now delete the record
+        p = self.make_name_packet(dns.DNS_OPCODE_UPDATE)
+        updates = []
+
+        name = self.get_dns_domain()
+
+        u = self.make_name_question(name, dns.DNS_QTYPE_SOA, dns.DNS_QCLASS_IN)
+        updates.append(u)
+        self.finish_name_packet(p, updates)
+
+        updates = []
+        r = dns.res_rec()
+        r.name = NAME
+        r.rr_type = dns.DNS_QTYPE_TXT
+        r.rr_class = dns.DNS_QCLASS_NONE
+        r.ttl = 0
+        r.length = 0xffff
+        rdata = dns.txt_record()
+        rdata.txt = '"This is a test"'
+        r.rdata = rdata
+        updates.append(r)
+        p.nscount = len(updates)
+        p.nsrecs = updates
+
+        response = self.dns_transaction_udp(p)
+        self.assert_dns_rcode_equals(response, dns.DNS_RCODE_OK)
+
+        # check it's gone
+        p = self.make_name_packet(dns.DNS_OPCODE_QUERY)
+        questions = []
+
+        q = self.make_name_question(NAME, dns.DNS_QTYPE_TXT, dns.DNS_QCLASS_IN)
+        questions.append(q)
+
+        self.finish_name_packet(p, questions)
+        response = self.dns_transaction_udp(p)
+        self.assert_dns_rcode_equals(response, dns.DNS_RCODE_NXDOMAIN)
+
+        # recreate the record
+        p = self.make_name_packet(dns.DNS_OPCODE_UPDATE)
+        updates = []
+
+        name = self.get_dns_domain()
+
+        u = self.make_name_question(name, dns.DNS_QTYPE_SOA, dns.DNS_QCLASS_IN)
+        updates.append(u)
+        self.finish_name_packet(p, updates)
+
+        updates = []
+        r = dns.res_rec()
+        r.name = NAME
+        r.rr_type = dns.DNS_QTYPE_TXT
+        r.rr_class = dns.DNS_QCLASS_IN
+        r.ttl = 900
+        r.length = 0xffff
+        rdata = dns.txt_record()
+        rdata.txt = '"This is a test"'
+        r.rdata = rdata
+        updates.append(r)
+        p.nscount = len(updates)
+        p.nsrecs = updates
+
+        response = self.dns_transaction_udp(p)
+        self.assert_dns_rcode_equals(response, dns.DNS_RCODE_OK)
+
+        # Now check the record is around
+        p = self.make_name_packet(dns.DNS_OPCODE_QUERY)
+        questions = []
+        q = self.make_name_question(NAME, dns.DNS_QTYPE_TXT, dns.DNS_QCLASS_IN)
+        questions.append(q)
+
+        self.finish_name_packet(p, questions)
+        response = self.dns_transaction_udp(p)
+        self.assert_dns_rcode_equals(response, dns.DNS_RCODE_OK)
+
     def test_update_add_mx_record(self):
         "test adding MX records works"
         p = self.make_name_packet(dns.DNS_OPCODE_UPDATE)