[3222] b10-dhcp6 now controls D2ClientMgr

Added D2ClientMgr send mode control and error handler
to Dhcp6vSrv and use of each to ControlledDhcpv6Srv.
Added new unit test files d2_unittest.h and cc.

src/bin/dhcp6/ctrl_dhcp6_srv.cc

@@ -114,6 +114,16 @@ ControlledDhcpv6Srv::dhcp6ConfigHandler(ConstElementPtr new_config) {
         return (answer);
     }
 
+    // Server will start DDNS communications if its enabled.
+    try {
+        server_->startD2();
+    } catch (const std::exception& ex) {
+        std::ostringstream err;
+        err << "error starting DHCP_DDNS client "
+                " after server reconfiguration: " << ex.what();
+        return (isc::config::createAnswer(1, err.str()));
+    }
+
     // Configuration may change active interfaces. Therefore, we have to reopen
     // sockets according to new configuration. This operation is not exception
     // safe and we really don't want to emit exceptions to the callback caller.
@@ -212,6 +222,10 @@ void ControlledDhcpv6Srv::establishSession() {
     try {
         // Pull the full configuration out from the session.
         configureDhcp6Server(*this, config_session_->getFullConfig());
+
+        // Server will start DDNS communications if its enabled.
+        server_->startD2();
+
         // Configuration may disable or enable interfaces so we have to
         // reopen sockets according to new configuration.
         openActiveSockets(getPort());

src/bin/dhcp6/dhcp6_messages.mes

@@ -544,3 +544,8 @@ recently and does not recognize its well-behaving clients. This is more
 probable if you see many such messages. Clients will recover from this,
 but they will most likely get a different IP addresses and experience
 a brief service interruption.
+
+% DHCP6_DDNS_REQUEST_SEND_FAILED failed sending a request to b10-dhcp-ddns, error : %1,  ncr: %2
+This error message indicates that IPv6 DHCP server attempted to send a DDNS
+update reqeust to the DHCP-DDNS server.  This is most likely a configuration or
+networking error.

src/bin/dhcp6/dhcp6_srv.cc

@@ -2455,5 +2455,29 @@ Dhcpv6Srv::generateFqdn(const Pkt6Ptr& answer) {
     }
 }
 
+void
+Dhcpv6Srv::startD2() {
+    D2ClientMgr& d2_mgr = CfgMgr::instance().getD2ClientMgr();
+    if (d2_mgr.ddnsEnabled()) {
+        // Updates are enabled, so lets start the sender, passing in
+        // our error handler.
+        // This may throw so wherever this is called needs to ready.
+        d2_mgr.startSender(boost::bind(&Dhcpv6Srv::d2ClientErrorHandler,
+                                       this, _1, _2));
+    }
+}
+
+void
+Dhcpv6Srv::d2ClientErrorHandler(const
+                                dhcp_ddns::NameChangeSender::Result result,
+                                dhcp_ddns::NameChangeRequestPtr& ncr) {
+    LOG_ERROR(dhcp6_logger, DHCP6_DDNS_REQUEST_SEND_FAILED).
+              arg(result).arg((ncr ? ncr->toText() : " NULL "));
+    // We cannot communicate with b10-dhcp-ddns, suspend futher updates.
+    /// @todo We may wish to revisit this, but for now we will simpy turn
+    /// them off.
+    CfgMgr::instance().getD2ClientMgr().suspendUpdates();
+}
+
 };
 };

src/bin/dhcp6/dhcp6_srv.h

@@ -24,6 +24,7 @@
 #include <dhcp/option_definition.h>
 #include <dhcp/pkt6.h>
 #include <dhcpsrv/alloc_engine.h>
+#include <dhcpsrv/d2_client_mgr.h>
 #include <dhcpsrv/subnet.h>
 #include <hooks/callout_handle.h>
 
@@ -117,6 +118,31 @@ public:
     /// @param port UDP port on which server should listen.
     static void openActiveSockets(const uint16_t port);
 
+    /// @brief Starts DHCP_DDNS client IO if DDNS updates are enabled.
+    ///
+    /// If updates are enabled, it Instructs the D2ClientMgr singleton to
+    /// enter send mode.  If D2ClientMgr encounters errors it may throw
+    /// D2ClientErrors. This method does not catch exceptions.
+    void startD2();
+
+    /// @brief Implements the error handler for DHCP_DDNS IO errors
+    ///
+    /// Invoked when a NameChangeRequest send to b10-dhcp-ddns completes with
+    /// a failed status.  These are communications errors, not data related
+    /// failures.
+    ///
+    /// This method logs the failure and then suspends all further updates.
+    /// Updating can only be restored by reconfiguration or restarting the
+    /// server.  There is currently no retry logic so the first IO error that
+    /// occurs will suspend updates.
+    /// @todo We may wish to make this more robust or sophisticated.
+    ///
+    /// @param result Result code of the send operation.
+    /// @param ncr NameChangeRequest which failed to send.
+    virtual void d2ClientErrorHandler(const dhcp_ddns::
+                                      NameChangeSender::Result result,
+                                      dhcp_ddns::NameChangeRequestPtr& ncr);
+
 protected:
 
     /// @brief Compare received server id with our server id

src/bin/dhcp6/tests/Makefile.am

@@ -75,6 +75,7 @@ dhcp6_unittests_SOURCES += hooks_unittest.cc
 dhcp6_unittests_SOURCES += dhcp6_test_utils.cc dhcp6_test_utils.h
 dhcp6_unittests_SOURCES += ctrl_dhcp6_srv_unittest.cc
 dhcp6_unittests_SOURCES += config_parser_unittest.cc
+dhcp6_unittests_SOURCES += d2_unittest.cc d2_unittest.h
 dhcp6_unittests_SOURCES += marker_file.cc
 dhcp6_unittests_SOURCES += ../dhcp6_srv.h ../dhcp6_srv.cc
 dhcp6_unittests_SOURCES += ../dhcp6_log.h ../dhcp6_log.cc