[3295] Generate client FQDN using leased IP address.

src/bin/dhcp6/dhcp6_srv.cc

@@ -1017,13 +1017,14 @@ Dhcpv6Srv::processClientFqdn(const Pkt6Ptr& question, const Pkt6Ptr& answer) {
     // generate one.
     if (fqdn->getDomainNameType() == Option6ClientFqdn::PARTIAL) {
         std::ostringstream name;
-        if (fqdn->getDomainName().empty()) {
-            name << FQDN_GENERATED_PARTIAL_NAME;
+        if (fqdn->getDomainName().empty() || FQDN_REPLACE_CLIENT_NAME) {
+            fqdn->setDomainName("", Option6ClientFqdn::PARTIAL);
+
         } else {
             name << fqdn->getDomainName();
+            name << "." << FQDN_PARTIAL_SUFFIX;
+            fqdn_resp->setDomainName(name.str(), Option6ClientFqdn::FULL);
         }
-        name << "." << FQDN_PARTIAL_SUFFIX;
-        fqdn_resp->setDomainName(name.str(), Option6ClientFqdn::FULL);
 
     // Server may be configured to replace a name supplied by a client,
     // even if client supplied fully qualified domain-name.

src/bin/dhcp6/tests/fqdn_unittest.cc

@@ -266,7 +266,19 @@ public:
         EXPECT_EQ(flag_o, answ_fqdn->getFlag(Option6ClientFqdn::FLAG_O));
 
         EXPECT_EQ(exp_domain_name, answ_fqdn->getDomainName());
-        EXPECT_EQ(Option6ClientFqdn::FULL, answ_fqdn->getDomainNameType());
+        // If server is configured to generate full FQDN for a client, and/or
+        // client sent empty FQDN the expected result of the processing by
+        // processClientFqdn is an empty, partial FQDN. This is an indication
+        // for the code which performs lease allocation that the FQDN has to
+        // be generated from the lease address.
+        if (exp_domain_name.empty()) {
+            EXPECT_EQ(Option6ClientFqdn::PARTIAL,
+                      answ_fqdn->getDomainNameType());
+
+        } else {
+            EXPECT_EQ(Option6ClientFqdn::FULL, answ_fqdn->getDomainNameType());
+
+        }
     }
 
     /// @brief Tests that the client's message holding an FQDN is processed
@@ -409,8 +421,7 @@ TEST_F(FqdnDhcpv6SrvTest, serverAAAAUpdatePartialName) {
 // that server performs AAAA update.
 TEST_F(FqdnDhcpv6SrvTest, serverAAAAUpdateNoName) {
     testFqdn(DHCPV6_SOLICIT, Option6ClientFqdn::FLAG_S, "",
-             Option6ClientFqdn::PARTIAL, Option6ClientFqdn::FLAG_S,
-             "myhost.example.com.");
+             Option6ClientFqdn::PARTIAL, Option6ClientFqdn::FLAG_S, "");
 }
 
 // Test server's response when client requests no DNS update.