[PATCH 4/5] dns: Add support for MX queries

[Kai Blin]

Due to an oversight, the internal DNS server supports MX record updates,
but not MX record queries. Add support for MX queries and tests.

This should fix bug #9485

Signed-off-by: Kai Blin <kai at samba.org>
---
 python/samba/tests/dns.py      | 43 ++++++++++++++++++++++++++++++++++++++++++
 source4/dns_server/dns_query.c |  8 ++++++++
 2 files changed, 51 insertions(+)

diff --git a/python/samba/tests/dns.py b/python/samba/tests/dns.py
index 49d699e..a29025d 100644
--- a/python/samba/tests/dns.py
+++ b/python/samba/tests/dns.py
@@ -510,6 +510,49 @@ class TestDNSUpdates(DNSTest):
         response = self.dns_transaction_udp(p)
         self.assert_dns_rcode_equals(response, dns.DNS_RCODE_NXDOMAIN)
 
+    def test_update_add_mx_record(self):
+        "test adding MX records works"
+        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 = "%s" % self.get_dns_domain()
+        r.rr_type = dns.DNS_QTYPE_MX
+        r.rr_class = dns.DNS_QCLASS_IN
+        r.ttl = 900
+        r.length = 0xffff
+        rdata = dns.mx_record()
+        rdata.preference = 10
+        rdata.exchange = 'mail.%s' % self.get_dns_domain()
+        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)
+
+        p = self.make_name_packet(dns.DNS_OPCODE_QUERY)
+        questions = []
+
+        name = "%s" % self.get_dns_domain()
+        q = self.make_name_question(name, dns.DNS_QTYPE_MX, 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)
+        self.assertEqual(response.ancount, 1)
+        self.assertEqual(response.answers[0].rdata.preference, 10)
+        self.assertEqual(response.answers[0].rdata.exchange, 'mail.%s' % self.get_dns_domain())
+
 
 class TestComplexQueries(DNSTest):
 
diff --git a/source4/dns_server/dns_query.c b/source4/dns_server/dns_query.c
index 3592110..4ad14b9 100644
--- a/source4/dns_server/dns_query.c
+++ b/source4/dns_server/dns_query.c
@@ -92,6 +92,14 @@ static WERROR create_response_rr(const struct dns_name_question *question,
 	case DNS_QTYPE_PTR:
 		ans[ai].rdata.ptr_record = talloc_strdup(ans, rec->data.ptr);
 		break;
+	case DNS_QTYPE_MX:
+		ans[ai].rdata.mx_record.preference = rec->data.mx.wPriority;
+		ans[ai].rdata.mx_record.exchange = talloc_strdup(
+			ans, rec->data.mx.nameTarget);
+		if (ans[ai].rdata.mx_record.exchange == NULL) {
+			return WERR_NOMEM;
+		}
+		break;
 	case DNS_QTYPE_TXT:
 		tmp = talloc_asprintf(ans, "\"%s\"", rec->data.txt.str[0]);
 		W_ERROR_HAVE_NO_MEMORY(tmp);
-- 
1.8.1.2