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[3282] Use DDNS configuration values in b10-dhcp4

Replaced hard-coded constants in dhcp4_srv.cc with methods and
logic in D2ClientMgr to implement behavior changes based on
dhcp-ddns configuration values.
Thomas Markwalder 11 years ago
parent
commit
c75896605b
2 changed files with 394 additions and 214 deletions
  1. 62 144
      src/bin/dhcp4/dhcp4_srv.cc
  2. 332 70
      src/bin/dhcp4/tests/fqdn_unittest.cc

+ 62 - 144
src/bin/dhcp4/dhcp4_srv.cc

@@ -79,36 +79,6 @@ Dhcp4Hooks Hooks;
 namespace isc {
 namespace dhcp {
 
-namespace {
-
-// @todo The following constants describe server's behavior with respect to the
-// DHCPv4 Client FQDN Option sent by a client. They will be removed
-// when DDNS parameters for DHCPv4 are implemented with the ticket #3033.
-
-// @todo Additional configuration parameter which we may consider is the one
-// that controls whether the DHCP server sends the removal NameChangeRequest
-// if it discovers that the entry for the particular client exists or that
-// it always updates the DNS.
-
-// Should server always include the FQDN option in its response, regardless
-// if it has been requested in Parameter Request List Option (Disabled).
-const bool FQDN_ALWAYS_INCLUDE = false;
-// Enable A RR update delegation to the client (Disabled).
-const bool FQDN_ALLOW_CLIENT_UPDATE = false;
-// 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).
-const bool FQDN_OVERRIDE_CLIENT_UPDATE = true;
-// The fully qualified domain-name suffix if partial name provided by
-// a client.
-const char* FQDN_PARTIAL_SUFFIX = "example.com";
-// Should server replace the domain-name supplied by the client (Disabled).
-const bool FQDN_REPLACE_CLIENT_NAME = false;
-
-}
-
 Dhcpv4Srv::Dhcpv4Srv(uint16_t port, const char* dbconfig, const bool use_bcast,
                      const bool direct_response_desired)
 : shutdown_(true), alloc_engine_(), port_(port),
@@ -580,8 +550,8 @@ Dhcpv4Srv::appendServerID(const Pkt4Ptr& response) {
     // The source address for the outbound message should have been set already.
     // This is the address that to the best of the server's knowledge will be
     // available from the client.
-    // @todo: perhaps we should consider some more sophisticated server id
-    // generation, but for the current use cases, it should be ok.
+    /// @todo: perhaps we should consider some more sophisticated server id
+    /// generation, but for the current use cases, it should be ok.
     response->addOption(OptionPtr(new Option4AddrLst(DHO_DHCP_SERVER_IDENTIFIER,
                                                      response->getLocalAddr()))
                         );
@@ -650,8 +620,8 @@ Dhcpv4Srv::appendRequestedVendorOptions(const Pkt4Ptr& question, Pkt4Ptr& answer
     uint32_t vendor_id = vendor_req->getVendorId();
 
     // Let's try to get ORO within that vendor-option
-    /// @todo This is very specific to vendor-id=4491 (Cable Labs). Other vendors
-    /// may have different policies.
+    /// @todo This is very specific to vendor-id=4491 (Cable Labs). Other
+    /// vendors may have different policies.
     OptionUint8ArrayPtr oro =
         boost::dynamic_pointer_cast<OptionUint8Array>(vendor_req->getOption(DOCSIS3_V4_ORO));
 
@@ -757,68 +727,19 @@ Dhcpv4Srv::processClientFqdnOption(const Option4ClientFqdnPtr& fqdn,
     // response to a client.
     Option4ClientFqdnPtr fqdn_resp(new Option4ClientFqdn(*fqdn));
 
-    // RFC4702, section 4 - set 'NOS' flags to 0.
-    fqdn_resp->setFlag(Option4ClientFqdn::FLAG_S, 0);
-    fqdn_resp->setFlag(Option4ClientFqdn::FLAG_O, 0);
-    fqdn_resp->setFlag(Option4ClientFqdn::FLAG_N, 0);
-
-    // Conditions when N flag has to be set to indicate that server will not
-    // perform DNS updates:
-    // 1. Updates are globally disabled,
-    // 2. Client requested no update and server respects it,
-    // 3. Client requested that the forward DNS update is delegated to the
-    //    client but server neither respects requests for forward update
-    //    delegation nor it is configured to send update on its own when
-    //    client requested delegation.
-    if (!FQDN_ENABLE_UPDATE ||
-        (fqdn->getFlag(Option4ClientFqdn::FLAG_N) &&
-         !FQDN_OVERRIDE_NO_UPDATE) ||
-        (!fqdn->getFlag(Option4ClientFqdn::FLAG_S) &&
-         !FQDN_ALLOW_CLIENT_UPDATE && !FQDN_OVERRIDE_CLIENT_UPDATE)) {
-        fqdn_resp->setFlag(Option4ClientFqdn::FLAG_N, true);
-
-    // Conditions when S flag is set to indicate that server will perform DNS
-    // update on its own:
-    // 1. Client requested that server performs DNS update and DNS updates are
-    //    globally enabled.
-    // 2. Client requested that server delegates forward update to the client
-    //    but server doesn't respect requests for delegation and it is
-    // configured to perform an update on its own when client requested the
-    // delegation.
-    } else  if (fqdn->getFlag(Option4ClientFqdn::FLAG_S) ||
-                (!fqdn->getFlag(Option4ClientFqdn::FLAG_S) &&
-                 !FQDN_ALLOW_CLIENT_UPDATE && FQDN_OVERRIDE_CLIENT_UPDATE)) {
-        fqdn_resp->setFlag(Option4ClientFqdn::FLAG_S, true);
-    }
-
-    // Server MUST set the O flag if it has overriden the client's setting
-    // of S flag.
-    if (fqdn->getFlag(Option4ClientFqdn::FLAG_S) !=
-        fqdn_resp->getFlag(Option4ClientFqdn::FLAG_S)) {
-        fqdn_resp->setFlag(Option4ClientFqdn::FLAG_O, true);
-    }
+    // Set the server S, N, and O flags based on client's flags and
+    // current configuration.
+    D2ClientMgr& d2_mgr = CfgMgr::instance().getD2ClientMgr();
+    d2_mgr.adjustFqdnFlags<Option4ClientFqdn>(*fqdn, *fqdn_resp);
 
-    // If client suppled partial or empty domain-name, server should generate
-    // one.
-    if (fqdn->getDomainNameType() == Option4ClientFqdn::PARTIAL) {
-        std::ostringstream name;
-        if (fqdn->getDomainName().empty() || FQDN_REPLACE_CLIENT_NAME) {
-            fqdn_resp->setDomainName("", Option4ClientFqdn::PARTIAL);
+    // Carry over the client's E flag.
+    fqdn_resp->setFlag(Option4ClientFqdn::FLAG_E,
+                       fqdn->getFlag(Option4ClientFqdn::FLAG_E));
 
-        } else {
-            name << fqdn->getDomainName();
-            name << "." << FQDN_PARTIAL_SUFFIX;
-            fqdn_resp->setDomainName(name.str(), Option4ClientFqdn::FULL);
 
-        }
-
-    // Server may be configured to replace a name supplied by a client, even if
-    // client supplied fully qualified domain-name. The empty domain-name is
-    // is set to indicate that the name must be generated when the new lease
-    // is acquired.
-    } else if(FQDN_REPLACE_CLIENT_NAME) {
-        fqdn_resp->setDomainName("", Option4ClientFqdn::PARTIAL);
-    }
+    // Adjust the domain name based on domain name value and type sent by the
+    // client and current configuration.
+    d2_mgr.adjustDomainName<Option4ClientFqdn>(*fqdn, *fqdn_resp);
 
     // Add FQDN option to the response message. Note that, there may be some
     // cases when server may choose not to include the FQDN option in a
@@ -838,15 +759,20 @@ Dhcpv4Srv::processClientFqdnOption(const Option4ClientFqdnPtr& fqdn,
 void
 Dhcpv4Srv::processHostnameOption(const OptionCustomPtr& opt_hostname,
                                  Pkt4Ptr& answer) {
+    // Fetch D2 configuration.
+    D2ClientMgr& d2_mgr = CfgMgr::instance().getD2ClientMgr();
+
     // Do nothing if the DNS updates are disabled.
-    if (!FQDN_ENABLE_UPDATE) {
+    if (!d2_mgr.ddnsEnabled()) {
         return;
     }
 
     std::string hostname = isc::util::str::trim(opt_hostname->readString());
     unsigned int label_count = OptionDataTypeUtil::getLabelCount(hostname);
     // The hostname option sent by the client should be at least 1 octet long.
-    // If it isn't we ignore this option.
+    // If it isn't we ignore this option. (Per RFC 2131, section 3.14)
+    /// @todo It would be more liberal to accept this and let it fall into
+    /// the case  of replace or less than two below.
     if (label_count == 0) {
         LOG_DEBUG(dhcp4_logger, DBG_DHCP4_DETAIL_DATA, DHCP4_EMPTY_HOSTNAME);
         return;
@@ -864,21 +790,20 @@ Dhcpv4Srv::processHostnameOption(const OptionCustomPtr& opt_hostname,
     // By checking the number of labels present in the hostname we may infer
     // whether client has sent the fully qualified or unqualified hostname.
 
-    // @todo We may want to reconsider whether it is appropriate for the
-    // client to send a root domain name as a Hostname. There are
-    // also extensions to the auto generation of the client's name,
-    // e.g. conversion to the puny code which may be considered at some point.
-    // For now, we just remain liberal and expect that the DNS will handle
-    // conversion if needed and possible.
-    if (FQDN_REPLACE_CLIENT_NAME || (label_count < 2)) {
+    /// @todo We may want to reconsider whether it is appropriate for the
+    /// client to send a root domain name as a Hostname. There are
+    /// also extensions to the auto generation of the client's name,
+    /// e.g. conversion to the puny code which may be considered at some point.
+    /// For now, we just remain liberal and expect that the DNS will handle
+    /// conversion if needed and possible.
+    if ((d2_mgr.getD2ClientConfig()->getReplaceClientName()) ||
+        (label_count < 2)) {
         opt_hostname_resp->writeString("");
-    // If there are two labels, it means that the client has specified
-    // the unqualified name. We have to concatenate the unqalified name
-    // with the domain name.
     } else if (label_count == 2) {
-        std::ostringstream resp_hostname;
-        resp_hostname << hostname << "." << FQDN_PARTIAL_SUFFIX << ".";
-        opt_hostname_resp->writeString(resp_hostname.str());
+        // If there are two labels, it means that the client has specified
+        // the unqualified name. We have to concatenate the unqalified name
+        // with the domain name.
+        opt_hostname_resp->writeString(d2_mgr.qualifyName(hostname));
     }
 
     answer->addOption(opt_hostname_resp);
@@ -969,9 +894,9 @@ queueNameChangeRequest(const isc::dhcp_ddns::NameChangeType chg_type,
 void
 Dhcpv4Srv::sendNameChangeRequests() {
     while (!name_change_reqs_.empty()) {
-        // @todo Once next NameChangeRequest is picked from the queue
-        // we should send it to the b10-dhcp_ddns module. Currently we
-        // just drop it.
+        /// @todo Once next NameChangeRequest is picked from the queue
+        /// we should send it to the b10-dhcp_ddns module. Currently we
+        /// just drop it.
         name_change_reqs_.pop();
     }
 }
@@ -990,8 +915,8 @@ Dhcpv4Srv::assignLease(const Pkt4Ptr& question, Pkt4Ptr& answer) {
         // thing this client can get is some global information (like DNS
         // servers).
 
-        // perhaps this should be logged on some higher level? This is most likely
-        // configuration bug.
+        // perhaps this should be logged on some higher level? This is most
+        // likely configuration bug.
         LOG_ERROR(dhcp4_logger, DHCP4_SUBNET_SELECTION_FAILED)
             .arg(question->getRemoteAddr().toText())
             .arg(serverReceivedPacketName(question->getType()));
@@ -1004,7 +929,7 @@ Dhcpv4Srv::assignLease(const Pkt4Ptr& question, Pkt4Ptr& answer) {
     // as siaddr has nothing to do with a lease, but otherwise we would have
     // to select subnet twice (performance hit) or update too many functions
     // at once.
-    // @todo: move subnet selection to a common code
+    /// @todo: move subnet selection to a common code
     answer->setSiaddr(subnet->getSiaddr());
 
     LOG_DEBUG(dhcp4_logger, DBG_DHCP4_DETAIL_DATA, DHCP4_SUBNET_SELECTED)
@@ -1047,8 +972,8 @@ Dhcpv4Srv::assignLease(const Pkt4Ptr& question, Pkt4Ptr& answer) {
             (answer->getOption(DHO_HOST_NAME));
         if (opt_hostname) {
             hostname = opt_hostname->readString();
-            // @todo It could be configurable what sort of updates the server
-            // is doing when Hostname option was sent.
+            /// @todo It could be configurable what sort of updates the
+            /// server is doing when Hostname option was sent.
             fqdn_fwd = true;
             fqdn_rev = true;
         }
@@ -1058,7 +983,7 @@ Dhcpv4Srv::assignLease(const Pkt4Ptr& question, Pkt4Ptr& answer) {
     // will try to honour the hint, but it is just a hint - some other address
     // may be used instead. If fake_allocation is set to false, the lease will
     // be inserted into the LeaseMgr as well.
-    // @todo pass the actual FQDN data.
+    /// @todo pass the actual FQDN data.
     Lease4Ptr old_lease;
     Lease4Ptr lease = alloc_engine_->allocateLease4(subnet, client_id, hwaddr,
                                                       hint, fqdn_fwd, fqdn_rev,
@@ -1083,14 +1008,9 @@ Dhcpv4Srv::assignLease(const Pkt4Ptr& question, Pkt4Ptr& answer) {
         // generating the entire hostname for the client. The example of the
         // client's name, generated from the IP address is: host-192-0-2-3.
         if ((fqdn || opt_hostname) && lease->hostname_.empty()) {
-            hostname = lease->addr_.toText();
-            // Replace dots with hyphens.
-            std::replace(hostname.begin(), hostname.end(), '.', '-');
-            ostringstream stream;
-            // The partial suffix will need to be replaced with the actual
-            // domain-name for the client when configuration is implemented.
-            stream << "host-" << hostname << "." << FQDN_PARTIAL_SUFFIX << ".";
-            lease->hostname_ = stream.str();
+            lease->hostname_ = CfgMgr::instance()
+                               .getD2ClientMgr().generateFqdn(lease->addr_);
+
             // The operations below are rather safe, but we want to catch
             // any potential exceptions (e.g. invalid lease database backend
             // implementation) and log an error.
@@ -1122,22 +1042,18 @@ Dhcpv4Srv::assignLease(const Pkt4Ptr& question, Pkt4Ptr& answer) {
         // Subnet mask (type 1)
         answer->addOption(getNetmaskOption(subnet));
 
-        // @todo: send renew timer option (T1, option 58)
-        // @todo: send rebind timer option (T2, option 59)
+        /// @todo: send renew timer option (T1, option 58)
+        /// @todo: send rebind timer option (T2, option 59)
 
-        // @todo Currently the NameChangeRequests are always generated if
-        // real (not fake) allocation is being performed. Should we have
-        // control switch to enable/disable NameChangeRequest creation?
-        // Perhaps we need a way to detect whether the b10-dhcp-ddns module
-        // is up an running?
-        if (!fake_allocation) {
+        // Create NameChangeRequests if DDNS is enabled and this is a
+        // real allocation.
+        if (!fake_allocation && CfgMgr::instance().ddnsEnabled()) {
             try {
                 createNameChangeRequests(lease, old_lease);
             } catch (const Exception& ex) {
                 LOG_ERROR(dhcp4_logger, DHCP4_NCR_CREATION_FAILED)
                     .arg(ex.what());
             }
-
         }
 
     } else {
@@ -1178,8 +1094,8 @@ Dhcpv4Srv::adjustIfaceData(const Pkt4Ptr& query, const Pkt4Ptr& response) {
     // address for the response. Instead, we have to check what address our
     // socket is bound to and use it as a source address. This operation
     // may throw if for some reason the socket is closed.
-    // @todo Consider an optimization that we use local address from
-    // the query if this address is not broadcast.
+    /// @todo Consider an optimization that we use local address from
+    /// the query if this address is not broadcast.
     SocketInfo sock_info = IfaceMgr::instance().getSocket(*query);
     // Set local adddress, port and interface.
     response->setLocalAddr(sock_info.addr_);
@@ -1294,7 +1210,7 @@ Pkt4Ptr
 Dhcpv4Srv::processRequest(Pkt4Ptr& request) {
 
     /// @todo Uncomment this (see ticket #3116)
-    // sanityCheck(request, MANDATORY);
+    /// sanityCheck(request, MANDATORY);
 
     Pkt4Ptr ack = Pkt4Ptr
         (new Pkt4(DHCPACK, request->getTransid()));
@@ -1336,7 +1252,7 @@ void
 Dhcpv4Srv::processRelease(Pkt4Ptr& release) {
 
     /// @todo Uncomment this (see ticket #3116)
-    // sanityCheck(release, MANDATORY);
+    /// sanityCheck(release, MANDATORY);
 
     // Try to find client-id
     ClientIdPtr client_id;
@@ -1361,7 +1277,7 @@ Dhcpv4Srv::processRelease(Pkt4Ptr& release) {
         // Does the hardware address match? We don't want one client releasing
         // second client's leases.
         if (lease->hwaddr_ != release->getHWAddr()->hwaddr_) {
-            // @todo: Print hwaddr from lease as part of ticket #2589
+            /// @todo: Print hwaddr from lease as part of ticket #2589
             LOG_DEBUG(dhcp4_logger, DBG_DHCP4_DETAIL, DHCP4_RELEASE_FAIL_WRONG_HWADDR)
                 .arg(release->getCiaddr().toText())
                 .arg(client_id ? client_id->toText() : "(no client-id)")
@@ -1419,9 +1335,11 @@ Dhcpv4Srv::processRelease(Pkt4Ptr& release) {
                     .arg(client_id ? client_id->toText() : "(no client-id)")
                     .arg(release->getHWAddr()->toText());
 
-                // Remove existing DNS entries for the lease, if any.
-                queueNameChangeRequest(isc::dhcp_ddns::CHG_REMOVE, lease);
-
+                if (CfgMgr::instance().ddnsEnabled() &&
+                    CfgMgr::instance().getD2ClientConfig()->getRemoveOnRenew()) {
+                    // Remove existing DNS entries for the lease, if any.
+                    queueNameChangeRequest(isc::dhcp_ddns::CHG_REMOVE, lease);
+                }
             } else {
                 // Release failed -
                 LOG_ERROR(dhcp4_logger, DHCP4_RELEASE_FAIL)
@@ -1662,8 +1580,8 @@ Dhcpv4Srv::openActiveSockets(const uint16_t port,
     }
     // Let's reopen active sockets. openSockets4 will check internally whether
     // sockets are marked active or inactive.
-    // @todo Optimization: we should not reopen all sockets but rather select
-    // those that have been affected by the new configuration.
+    /// @todo Optimization: we should not reopen all sockets but rather select
+    /// those that have been affected by the new configuration.
     isc::dhcp::IfaceMgrErrorMsgCallback error_handler =
         boost::bind(&Dhcpv4Srv::ifaceMgrSocket4ErrorHandler, _1);
     if (!IfaceMgr::instance().openSockets4(port, use_bcast, error_handler)) {

+ 332 - 70
src/bin/dhcp4/tests/fqdn_unittest.cc

@@ -18,6 +18,7 @@
 #include <dhcp/option_int_array.h>
 #include <dhcp4/tests/dhcp4_test_utils.h>
 #include <dhcp_ddns/ncr_msg.h>
+#include <dhcpsrv/cfgmgr.h>
 
 #include <gtest/gtest.h>
 #include <boost/scoped_ptr.hpp>
@@ -32,13 +33,55 @@ namespace {
 
 class NameDhcpv4SrvTest : public Dhcpv4SrvFakeIfaceTest {
 public:
+
+    // Bit Constants for turning on and off DDNS configuration options.
+    static const uint16_t REMOVE_ON_RENEW = 1;
+    static const uint16_t ALWAYS_INCLUDE_FQDN = 2;
+    static const uint16_t OVERRIDE_NO_UPDATE = 4;
+    static const uint16_t OVERRIDE_CLIENT_UPDATE = 8;
+    static const uint16_t REPLACE_CLIENT_NAME = 16;
+
     NameDhcpv4SrvTest() : Dhcpv4SrvFakeIfaceTest() {
         srv_ = new NakedDhcpv4Srv(0);
+        // Config DDNS to be enabled, all controls off
+        enableD2();
     }
+
     virtual ~NameDhcpv4SrvTest() {
         delete srv_;
     }
 
+    /// @brief Sets the server's DDNS configuration to ddns updates disabled.
+    void disableD2() {
+        // Default constructor creates a config with DHCP-DDNS updates
+        // disabled.
+        D2ClientConfigPtr cfg(new D2ClientConfig());
+        CfgMgr::instance().setD2ClientConfig(cfg);
+    }
+
+    /// @brief Enables DHCP-DDNS updates with the given options enabled.
+    ///
+    /// Replaces the current D2ClientConfiguration with a configuration
+    /// which as updates enabled and the control options set based upon
+    /// the bit mask of options.
+    ///
+    /// @param mask Bit mask of configuration options that should be enabled.
+    void enableD2(const uint16_t mask = 0) {
+        D2ClientConfigPtr cfg;
+
+        ASSERT_NO_THROW(cfg.reset(new D2ClientConfig(true,
+                                  isc::asiolink::IOAddress("192.0.2.1"), 477,
+                                  dhcp_ddns::NCR_UDP, dhcp_ddns::FMT_JSON,
+                                  (mask & REMOVE_ON_RENEW),
+                                  (mask & ALWAYS_INCLUDE_FQDN),
+                                  (mask & OVERRIDE_NO_UPDATE),
+                                  (mask & OVERRIDE_CLIENT_UPDATE),
+                                  (mask & REPLACE_CLIENT_NAME),
+                                  "myhost", "example.com")));
+
+        CfgMgr::instance().setD2ClientConfig(cfg);
+    }
+
     // Create a lease to be used by various tests.
     Lease4Ptr createLease(const isc::asiolink::IOAddress& addr,
                           const std::string& hostname,
@@ -78,15 +121,18 @@ public:
         return (opt_hostname);
     }
 
-    // Generates partial hostname from the address. The format of the
-    // generated address is: host-A-B-C-D, where A.B.C.D is an IP
-    // address.
+    /// @brief Convenience method for generating an FQDN from an IP address.
+    ///
+    /// This is just a wrapper method around the D2ClientMgr's method for
+    /// generating domain names from the configured prefix, suffix, and a
+    /// given IP address.  This is useful for verifying that fully generated
+    /// names are correct.
+    ///
+    /// @param addr IP address used in the lease.
+    ///
+    /// @return An std::string contained the generated FQDN.
     std::string generatedNameFromAddress(const IOAddress& addr) {
-        std::string gen_name = addr.toText();
-        std::replace(gen_name.begin(), gen_name.end(), '.', '-');
-        std::ostringstream hostname;
-        hostname << "host-" << gen_name;
-        return (hostname.str());
+        return(CfgMgr::instance().getD2ClientMgr().generateFqdn(addr));
     }
 
     // Get the Client FQDN Option from the given message.
@@ -182,6 +228,21 @@ public:
         Option4ClientFqdnPtr fqdn = getClientFqdnOption(answer);
         ASSERT_TRUE(fqdn);
 
+        checkFqdnFlags(answer, exp_flags);
+
+        EXPECT_EQ(exp_domain_name, fqdn->getDomainName());
+        EXPECT_EQ(exp_domain_type, fqdn->getDomainNameType());
+
+    }
+
+    /// @brief Checks the packet's FQDN option flags against a given mask
+    ///
+    /// @param pkt IPv4 packet whose FQDN flags should be checked.
+    /// @param exp_flags Bit mask of flags that are expected to be true.
+    void checkFqdnFlags(const Pkt4Ptr& pkt, const uint8_t exp_flags) {
+        Option4ClientFqdnPtr fqdn = getClientFqdnOption(pkt);
+        ASSERT_TRUE(fqdn);
+
         const bool flag_n = (exp_flags & Option4ClientFqdn::FLAG_N) != 0;
         const bool flag_s = (exp_flags & Option4ClientFqdn::FLAG_S) != 0;
         const bool flag_o = (exp_flags & Option4ClientFqdn::FLAG_O) != 0;
@@ -191,12 +252,9 @@ public:
         EXPECT_EQ(flag_s, fqdn->getFlag(Option4ClientFqdn::FLAG_S));
         EXPECT_EQ(flag_o, fqdn->getFlag(Option4ClientFqdn::FLAG_O));
         EXPECT_EQ(flag_e, fqdn->getFlag(Option4ClientFqdn::FLAG_E));
-
-        EXPECT_EQ(exp_domain_name, fqdn->getDomainName());
-        EXPECT_EQ(exp_domain_type, fqdn->getDomainNameType());
-
     }
 
+
     // Processes the Hostname option in the client's message and returns
     // the hostname option which would be sent to the client. It will
     // throw NULL pointer if the hostname option is not to be included
@@ -221,8 +279,8 @@ public:
 
     }
 
-    // Test that the client message holding an FQDN is processed and the
-    // NameChangeRequests are generated.
+    // Test that the client message holding an FQDN is processed and
+    // that the response packet is as expected.
     void testProcessMessageWithFqdn(const uint8_t msg_type,
                             const std::string& hostname) {
         Pkt4Ptr req = generatePktWithFqdn(msg_type, Option4ClientFqdn::FLAG_S |
@@ -287,6 +345,50 @@ public:
         srv_->name_change_reqs_.pop();
     }
 
+
+    /// @brief Tests processing a request with the given client flags
+    ///
+    /// This method creates a request with its FQDN flags set to the given
+    /// value and submits it to the server for processing.  It then checks
+    /// the following:
+    /// 1. Did the server generate an ACK with the correct FQDN flags
+    /// 2. If the server should have generated an NCR, did it? and If
+    /// so was it correct?
+    ///
+    /// @param client_flags Mask of client FQDN flags which are true
+    /// @param response_flags Mask of expected FQDN flags in the response
+    void flagVsConfigScenario(const uint8_t client_flags,
+                       const uint8_t response_flags) {
+        Pkt4Ptr req = generatePktWithFqdn(DHCPREQUEST, client_flags,
+                                          "myhost.example.com.",
+                                          Option4ClientFqdn::FULL, true);
+
+        // Process the request.
+        Pkt4Ptr reply;
+        ASSERT_NO_THROW(reply = srv_->processRequest(req));
+
+        // Verify the response and flags.
+        checkResponse(reply, DHCPACK, 1234);
+        checkFqdnFlags(reply, response_flags);
+
+        // There should be an NCR only if response S flag is 1.
+        /// @todo This logic will need to change if forward and reverse
+        /// updates are ever controlled independently.
+        if ((response_flags & Option4ClientFqdn::FLAG_S) == 0) {
+            ASSERT_EQ(0, srv_->name_change_reqs_.size());
+        } else {
+            // Verify that there is one NameChangeRequest generated as expected.
+            ASSERT_EQ(1, srv_->name_change_reqs_.size());
+            verifyNameChangeRequest(isc::dhcp_ddns::CHG_ADD, true, true,
+                                    reply->getYiaddr().toText(),
+                                    "myhost.example.com.",
+                                    "", // empty DHCID means don't check it
+                                    time(NULL) + subnet_->getValid(),
+                                    subnet_->getValid(), true);
+        }
+    }
+
+
     NakedDhcpv4Srv* srv_;
 
 };
@@ -348,21 +450,101 @@ TEST_F(NameDhcpv4SrvTest, dhcidComputeFromHWAddr) {
     EXPECT_EQ(dhcid_ref, dhcid.toStr());
 }
 
+// Tests the following scenario:
+//  - Updates are enabled
+//  - All overrides are off
+//  - Client requests forward update  (N = 0, S = 1)
+//
+//  Server should perform the update:
+//  - Reponse flags should N = 0, S = 1, O = 0
+//  - Should queue an NCR
+TEST_F(NameDhcpv4SrvTest, updatesEnabled) {
+    flagVsConfigScenario((Option4ClientFqdn::FLAG_E |
+                          Option4ClientFqdn::FLAG_S),
+                          (Option4ClientFqdn::FLAG_E |
+                           Option4ClientFqdn::FLAG_S));
+}
 
-// Test that server confirms to perform the forward and reverse DNS update,
-// when client asks for it.
-TEST_F(NameDhcpv4SrvTest, serverUpdateForwardFqdn) {
-    Pkt4Ptr query = generatePktWithFqdn(DHCPREQUEST,
-                                        Option4ClientFqdn::FLAG_E |
-                                        Option4ClientFqdn::FLAG_S,
-                                        "myhost.example.com.",
-                                        Option4ClientFqdn::FULL,
-                                        true);
+// Tests the following scenario
+//  - Updates are disabled
+//  - Client requests forward update  (N = 0, S = 1)
+//
+//  Server should NOT perform updates:
+//   - Response flags should N = 1, S = 0, O = 1
+//   - Should not queue any NCRs
+TEST_F(NameDhcpv4SrvTest, updatesDisabled) {
+    disableD2();
+    flagVsConfigScenario((Option4ClientFqdn::FLAG_E |
+                          Option4ClientFqdn::FLAG_S),
+                          (Option4ClientFqdn::FLAG_E |
+                           Option4ClientFqdn::FLAG_N |
+                           Option4ClientFqdn::FLAG_O));
+}
 
-    testProcessFqdn(query,
-                    Option4ClientFqdn::FLAG_E | Option4ClientFqdn::FLAG_S,
-                    "myhost.example.com.");
+// Tests the following scenario:
+//  - Updates are enabled
+//  - All overrides are off.
+//  - Client requests no updates  (N = 1, S = 0)
+//
+//  Server should NOT perform updates:
+//  - Response flags should N = 1, S = 0, O = 0
+//  - Should not queue any NCRs
+TEST_F(NameDhcpv4SrvTest, respectNoUpdate) {
+    flagVsConfigScenario((Option4ClientFqdn::FLAG_E |
+                          Option4ClientFqdn::FLAG_N),
+                          (Option4ClientFqdn::FLAG_E |
+                           Option4ClientFqdn::FLAG_N));
+}
 
+// Tests the following scenario:
+//  - Updates are enabled
+//  - override-no-update is on
+//  - Client requests no updates  (N = 1, S = 0)
+//
+// Server should override "no update" request and perform updates:
+// - Response flags should be  N = 0, S = 1, O = 1
+// - Should queue an NCR
+TEST_F(NameDhcpv4SrvTest, overrideNoUpdate) {
+    enableD2(OVERRIDE_NO_UPDATE);
+    flagVsConfigScenario((Option4ClientFqdn::FLAG_E |
+                          Option4ClientFqdn::FLAG_N),
+                          (Option4ClientFqdn::FLAG_E |
+                           Option4ClientFqdn::FLAG_S |
+                           Option4ClientFqdn::FLAG_O));
+}
+
+// Tests the following scenario:
+//  - Updates are enabled
+//  - All overrides are off.
+//  - Client requests delegation  (N = 0, S = 0)
+//
+// Server should respect client's delegation request and NOT do updates:
+
+// - Response flags should be  N = 1, S = 0, O = 0
+// - Should not queue any NCRs
+TEST_F(NameDhcpv4SrvTest, respectClientDelegation) {
+
+    flagVsConfigScenario(Option4ClientFqdn::FLAG_E,
+                         (Option4ClientFqdn::FLAG_E |
+                          Option4ClientFqdn::FLAG_N));
+}
+
+// Tests the following scenario:
+//  - Updates are enabled
+//  - override-client-update is on.
+//  - Client requests delegation  (N = 0, S = 0)
+//
+// Server should override client's delegation request and do updates:
+// - Response flags should be  N = 0, S = 1, O = 1
+// - Should queue an NCR
+TEST_F(NameDhcpv4SrvTest, overrideClientDelegation) {
+    // Turn on override-client-update.
+    enableD2(OVERRIDE_CLIENT_UPDATE);
+
+    flagVsConfigScenario(Option4ClientFqdn::FLAG_E,
+                         (Option4ClientFqdn::FLAG_E |
+                          Option4ClientFqdn::FLAG_S |
+                          Option4ClientFqdn::FLAG_O));
 }
 
 // Test that server processes the Hostname option sent by a client and
@@ -447,34 +629,6 @@ TEST_F(NameDhcpv4SrvTest, serverUpdateForwardNoNameFqdn) {
 
 }
 
-// Test server's response when client requests no DNS update.
-TEST_F(NameDhcpv4SrvTest, noUpdateFqdn) {
-    Pkt4Ptr query = generatePktWithFqdn(DHCPREQUEST,
-                                        Option4ClientFqdn::FLAG_E |
-                                        Option4ClientFqdn::FLAG_N,
-                                        "myhost.example.com.",
-                                        Option4ClientFqdn::FULL,
-                                        true);
-    testProcessFqdn(query, Option4ClientFqdn::FLAG_E |
-                    Option4ClientFqdn::FLAG_N,
-                    "myhost.example.com.");
-}
-
-// Test that server does not accept delegation of the forward DNS update
-// to a client.
-TEST_F(NameDhcpv4SrvTest, clientUpdateNotAllowedFqdn) {
-    Pkt4Ptr query = generatePktWithFqdn(DHCPREQUEST,
-                                        Option4ClientFqdn::FLAG_E,
-                                        "myhost.example.com.",
-                                        Option4ClientFqdn::FULL,
-                                        true);
-
-    testProcessFqdn(query, Option4ClientFqdn::FLAG_E |
-                    Option4ClientFqdn::FLAG_S | Option4ClientFqdn::FLAG_O,
-                    "myhost.example.com.");
-
-}
-
 // Test that exactly one NameChangeRequest is generated when the new lease
 // has been acquired (old lease is NULL).
 TEST_F(NameDhcpv4SrvTest, createNameChangeRequestsNewLease) {
@@ -600,18 +754,42 @@ TEST_F(NameDhcpv4SrvTest, processRequestFqdnEmptyDomainName) {
 
     // Verify that there is one NameChangeRequest generated.
     ASSERT_EQ(1, srv_->name_change_reqs_.size());
+
     // The hostname is generated from the IP address acquired (yiaddr).
-    std::ostringstream hostname;
-    hostname << generatedNameFromAddress(reply->getYiaddr())
-             << ".example.com.";
+    std::string hostname = generatedNameFromAddress(reply->getYiaddr());
+
     verifyNameChangeRequest(isc::dhcp_ddns::CHG_ADD, true, true,
-                            reply->getYiaddr().toText(), hostname.str(),
+                            reply->getYiaddr().toText(), hostname,
                             "", // empty DHCID forces that it is not checked
                             time(NULL) + subnet_->getValid(),
                             subnet_->getValid(), true);
 }
 
 // Test that server generates client's hostname from the IP address assigned
+// to it when DHCPv4 Client FQDN option specifies an empty domain-name  AND
+// ddns updates are disabled.
+TEST_F(NameDhcpv4SrvTest, processRequestEmptyDomainNameDisabled) {
+    disableD2();
+    Pkt4Ptr req = generatePktWithFqdn(DHCPREQUEST, Option4ClientFqdn::FLAG_S |
+                                      Option4ClientFqdn::FLAG_E,
+                                      "", Option4ClientFqdn::PARTIAL, true);
+    Pkt4Ptr reply;
+    ASSERT_NO_THROW(reply = srv_->processRequest(req));
+
+    checkResponse(reply, DHCPACK, 1234);
+
+    Option4ClientFqdnPtr fqdn = getClientFqdnOption(reply);
+    ASSERT_TRUE(fqdn);
+
+    // The hostname is generated from the IP address acquired (yiaddr).
+    std::string hostname = generatedNameFromAddress(reply->getYiaddr());
+
+    EXPECT_EQ(hostname, fqdn->getDomainName());
+    EXPECT_EQ(Option4ClientFqdn::FULL, fqdn->getDomainNameType());
+}
+
+
+// Test that server generates client's hostname from the IP address assigned
 // to it when Hostname option carries the top level domain-name.
 TEST_F(NameDhcpv4SrvTest, processRequestEmptyHostname) {
     Pkt4Ptr req = generatePktWithHostname(DHCPREQUEST, ".");
@@ -626,11 +804,12 @@ TEST_F(NameDhcpv4SrvTest, processRequestEmptyHostname) {
 
     // Verify that there is one NameChangeRequest generated.
     ASSERT_EQ(1, srv_->name_change_reqs_.size());
+
     // The hostname is generated from the IP address acquired (yiaddr).
-    std::ostringstream hostname;
-    hostname << generatedNameFromAddress(reply->getYiaddr()) << ".example.com.";
+    std::string hostname = generatedNameFromAddress(reply->getYiaddr());
+
     verifyNameChangeRequest(isc::dhcp_ddns::CHG_ADD, true, true,
-                            reply->getYiaddr().toText(), hostname.str(),
+                            reply->getYiaddr().toText(), hostname,
                             "", // empty DHCID forces that it is not checked
                             time(NULL), subnet_->getValid(), true);
 }
@@ -742,21 +921,26 @@ TEST_F(NameDhcpv4SrvTest, processTwoRequestsHostname) {
                             time(NULL), subnet_->getValid(), true);
 }
 
-// Test that when the Release message is sent for the previously acquired
-// lease, then server genenerates a NameChangeRequest to remove the entries
-// corresponding to the lease being released.
-TEST_F(NameDhcpv4SrvTest, processRequestRelease) {
+// Test that when a release message is sent for a previously acquired lease,
+// DDNS updates are enabled and remove-on-renew is true that the server
+// genenerates a NameChangeRequest to remove entries corresponding to the
+// released lease.
+TEST_F(NameDhcpv4SrvTest, processRequestReleaseRemoveOn) {
+    // Enable ddns updates and remove-on-renew .
+    enableD2(REMOVE_ON_RENEW);
+    ASSERT_TRUE(CfgMgr::instance().ddnsEnabled());
+    ASSERT_TRUE(CfgMgr::instance().getD2ClientConfig()->getRemoveOnRenew());
+
+    // Create and process a lease request so we have a lease to release.
     Pkt4Ptr req = generatePktWithFqdn(DHCPREQUEST, Option4ClientFqdn::FLAG_S |
                                       Option4ClientFqdn::FLAG_E,
                                       "myhost.example.com.",
                                       Option4ClientFqdn::FULL, true);
-
     Pkt4Ptr reply;
     ASSERT_NO_THROW(reply = srv_->processRequest(req));
-
     checkResponse(reply, DHCPACK, 1234);
 
-    // Verify that there is one NameChangeRequest generated.
+    // Verify that there is one NameChangeRequest generated for lease.
     ASSERT_EQ(1, srv_->name_change_reqs_.size());
     verifyNameChangeRequest(isc::dhcp_ddns::CHG_ADD, true, true,
                             reply->getYiaddr().toText(), "myhost.example.com.",
@@ -764,18 +948,96 @@ TEST_F(NameDhcpv4SrvTest, processRequestRelease) {
                             "965B68B6D438D98E680BF10B09F3BCF",
                             time(NULL), subnet_->getValid(), true);
 
-    // Create a Release message.
+    // Create and process the Release message.
     Pkt4Ptr rel = Pkt4Ptr(new Pkt4(DHCPRELEASE, 1234));
     rel->setCiaddr(reply->getYiaddr());
     rel->setRemoteAddr(IOAddress("192.0.2.3"));
     rel->addOption(generateClientId());
     rel->addOption(srv_->getServerID());
-
     ASSERT_NO_THROW(srv_->processRelease(rel));
 
     // The lease has been removed, so there should be a NameChangeRequest to
     // remove corresponding DNS entries.
     ASSERT_EQ(1, srv_->name_change_reqs_.size());
+    verifyNameChangeRequest(isc::dhcp_ddns::CHG_REMOVE, true, true,
+                            reply->getYiaddr().toText(), "myhost.example.com.",
+                            "00010132E91AA355CFBB753C0F0497A5A940436"
+                            "965B68B6D438D98E680BF10B09F3BCF",
+                            time(NULL), subnet_->getValid(), true);
 }
 
+// Test that when a Release message is sent for a previously acquired
+// lease and DDNS updates are enabled but remove-on-renew is off that server
+// does NOT generate NameChangeRequest to remove entries corresponding to
+// the released lease.
+TEST_F(NameDhcpv4SrvTest, processRequestReleaseRemoveOff) {
+    // Verify the config is as expected.
+    ASSERT_TRUE(CfgMgr::instance().ddnsEnabled());
+    ASSERT_FALSE(CfgMgr::instance().getD2ClientConfig()->getRemoveOnRenew());
+
+    // Create and process a lease request so we have a lease to release.
+    Pkt4Ptr req = generatePktWithFqdn(DHCPREQUEST, Option4ClientFqdn::FLAG_S |
+                                      Option4ClientFqdn::FLAG_E,
+                                      "myhost.example.com.",
+                                      Option4ClientFqdn::FULL, true);
+    Pkt4Ptr reply;
+    ASSERT_NO_THROW(reply = srv_->processRequest(req));
+    checkResponse(reply, DHCPACK, 1234);
+
+    // Verify that there is one NameChangeRequest generated for the new lease.
+    ASSERT_EQ(1, srv_->name_change_reqs_.size());
+    verifyNameChangeRequest(isc::dhcp_ddns::CHG_ADD, true, true,
+                            reply->getYiaddr().toText(), "myhost.example.com.",
+                            "00010132E91AA355CFBB753C0F0497A5A940436"
+                            "965B68B6D438D98E680BF10B09F3BCF",
+                            time(NULL), subnet_->getValid(), true);
+
+    // Create and process the Release message.
+    Pkt4Ptr rel = Pkt4Ptr(new Pkt4(DHCPRELEASE, 1234));
+    rel->setCiaddr(reply->getYiaddr());
+    rel->setRemoteAddr(IOAddress("192.0.2.3"));
+    rel->addOption(generateClientId());
+    rel->addOption(srv_->getServerID());
+    ASSERT_NO_THROW(srv_->processRelease(rel));
+
+    // With remove-on-renew off, there should be not be a NameChangeRequest
+    // for the remove.
+    ASSERT_EQ(0, srv_->name_change_reqs_.size());
+}
+
+// Test that when the Release message is sent for a previously acquired lease
+// and DDNS updates are disabled that server does NOT generate a
+// NameChangeRequest to remove entries corresponding to the released lease.
+TEST_F(NameDhcpv4SrvTest, processRequestReleaseUpdatesDisabled) {
+    // Disable DDNS.
+    disableD2();
+    ASSERT_FALSE(CfgMgr::instance().ddnsEnabled());
+
+    // Create and process a lease request so we have a lease to release.
+    Pkt4Ptr req = generatePktWithFqdn(DHCPREQUEST, Option4ClientFqdn::FLAG_S |
+                                      Option4ClientFqdn::FLAG_E,
+                                      "myhost.example.com.",
+                                      Option4ClientFqdn::FULL, true);
+    Pkt4Ptr reply;
+    ASSERT_NO_THROW(reply = srv_->processRequest(req));
+    checkResponse(reply, DHCPACK, 1234);
+
+    // With DDNS updates disabled, there should be not be a NameChangeRequest
+    // for the add.
+    ASSERT_EQ(0, srv_->name_change_reqs_.size());
+
+    // Create and process the Release message.
+    Pkt4Ptr rel = Pkt4Ptr(new Pkt4(DHCPRELEASE, 1234));
+    rel->setCiaddr(reply->getYiaddr());
+    rel->setRemoteAddr(IOAddress("192.0.2.3"));
+    rel->addOption(generateClientId());
+    rel->addOption(srv_->getServerID());
+    ASSERT_NO_THROW(srv_->processRelease(rel));
+
+    // With DDNS updates disabled, there should be not be a NameChangeRequest
+    // for the remove.
+    ASSERT_EQ(0, srv_->name_change_reqs_.size());
+}
+
+
 } // end of anonymous namespace