[3034] Replaced constant with CfgMgr::ddnsEnabled() in Dhcpv6Srv

Dhcpv6Srv now uses method in CfgMgr to test whether or not ddns updates
are enabled.  Add unit tests to verify NCRs are or are not created
accordingly.

src/bin/dhcp6/dhcp6_srv.cc

@@ -104,8 +104,6 @@ namespace {
 // DHCPv6 Client FQDN Option sent by a client. They will be removed
 // when DDNS parameters for DHCPv6 are implemented with the ticket #3034.
 
-// Globally enable updates (Enabled).
-const bool FQDN_ENABLE_UPDATE = true;
 // Do update, even if client requested no updates with N flag (Disabled).
 const bool FQDN_OVERRIDE_NO_UPDATE = false;
 // Server performs an update when client requested delegation (Enabled).
@@ -1030,7 +1028,7 @@ Dhcpv6Srv::processClientFqdn(const Pkt6Ptr& question, const Pkt6Ptr& answer) {
 void
 Dhcpv6Srv::createNameChangeRequests(const Pkt6Ptr& answer) {
     // Don't create NameChangeRequests if DNS updates are disabled.
-    if (!FQDN_ENABLE_UPDATE) {
+    if (!CfgMgr::instance().ddnsEnabled()) {
         return;
     }
 
@@ -1117,7 +1115,7 @@ Dhcpv6Srv::createNameChangeRequests(const Pkt6Ptr& answer) {
 void
 Dhcpv6Srv::createRemovalNameChangeRequest(const Lease6Ptr& lease) {
     // Don't create NameChangeRequests if DNS updates are disabled.
-    if (!FQDN_ENABLE_UPDATE) {
+    if (!CfgMgr::instance().ddnsEnabled()) {
         return;
     }
 

src/bin/dhcp6/tests/fqdn_unittest.cc

@@ -588,6 +588,34 @@ TEST_F(FqdnDhcpv6SrvTest, createNameChangeRequests) {
 
 }
 
+// Checks that NameChangeRequests to add entries are not
+// created when ddns updates are disabled.
+TEST_F(FqdnDhcpv6SrvTest, noAddRequestsWhenDisabled) {
+    NakedDhcpv6Srv srv(0);
+
+    // Disable DDNS udpates.
+    disableD2();
+
+    // Create Reply message with Client Id and Server id.
+    Pkt6Ptr answer = generateMessageWithIds(DHCPV6_REPLY, srv);
+
+    // Create three IAs, each having different address.
+    addIA(1234, IOAddress("2001:db8:1::1"), answer);
+
+    // Use domain name in upper case. It should be converted to lower-case
+    // before DHCID is calculated. So, we should get the same result as if
+    // we typed domain name in lower-case.
+    Option6ClientFqdnPtr fqdn = createClientFqdn(Option6ClientFqdn::FLAG_S,
+                                                 "MYHOST.EXAMPLE.COM",
+                                                 Option6ClientFqdn::FULL);
+    answer->addOption(fqdn);
+
+    // Create NameChangeRequest for the first allocated address.
+    ASSERT_NO_THROW(srv.createNameChangeRequests(answer));
+    ASSERT_TRUE(srv.name_change_reqs_.empty());
+}
+
+
 // Test creation of the NameChangeRequest to remove both forward and reverse
 // mapping for the given lease.
 TEST_F(FqdnDhcpv6SrvTest, createRemovalNameChangeRequestFwdRev) {
@@ -612,6 +640,27 @@ TEST_F(FqdnDhcpv6SrvTest, createRemovalNameChangeRequestFwdRev) {
 
 }
 
+// Checks that NameChangeRequests to remove entries are not created
+// when ddns updates are disabled.
+TEST_F(FqdnDhcpv6SrvTest, noRemovalsWhenDisabled) {
+    NakedDhcpv6Srv srv(0);
+
+    // Disable DDNS updates.
+    disableD2();
+
+    lease_->fqdn_fwd_ = true;
+    lease_->fqdn_rev_ = true;
+    // Part of the domain name is in upper case, to test that it gets converted
+    // to lower case before DHCID is computed. So, we should get the same DHCID
+    // as if we typed domain-name in lower case.
+    lease_->hostname_ = "MYHOST.example.com.";
+
+    ASSERT_NO_THROW(srv.createRemovalNameChangeRequest(lease_));
+
+    ASSERT_TRUE(srv.name_change_reqs_.empty());
+}
+
+
 // Test creation of the NameChangeRequest to remove reverse mapping for the
 // given lease.
 TEST_F(FqdnDhcpv6SrvTest, createRemovalNameChangeRequestRev) {