[master] Merge branch 'trac2637'

Conflicts:
	src/bin/dhcp4/config_parser.cc
	src/bin/dhcp6/config_parser.cc
	src/lib/dhcpsrv/dhcpsrv_messages.mes
	src/lib/dhcpsrv/memfile_lease_mgr.cc

diff --cc src/bin/dhcp4/config_parser.cc
Simple merge

diff --cc src/bin/dhcp4/dhcp4.spec
Simple merge

diff --cc src/bin/dhcp4/tests/config_parser_unittest.cc
Simple merge

diff --cc src/bin/dhcp4/tests/dhcp4_srv_unittest.cc
Simple merge

diff --cc src/bin/dhcp6/config_parser.cc
Simple merge

diff --cc src/bin/dhcp6/ctrl_dhcp6_srv.cc
index a1fe4e5f9ce93a6321f6a011b224c8e08406b366,f41e240eec4ea8b6f5e223fd7cb6dc6767fbd738..e4e17f1eaae6828f3e1d2d1a641659243d4098dd
--- 1/src/bin/dhcp6/ctrl_dhcp6_srv.cc
--- 2/src/bin/dhcp6/ctrl_dhcp6_srv.cc
+++ b/src/bin/dhcp6/ctrl_dhcp6_srv.cc
@@@ -42,22 -42,66 +42,65 @@@ using namespace std
  namespace isc {
  namespace dhcp {
  
 -
  ControlledDhcpv6Srv* ControlledDhcpv6Srv::server_ = NULL;
  
+ ConstElementPtr
+ ControlledDhcpv6Srv::dhcp6StubConfigHandler(ConstElementPtr) {
+     // This configuration handler is intended to be used only
+     // when the initial configuration comes in. To receive this
+     // configuration a pointer to this handler must be passed
+     // using ModuleCCSession constructor. This constructor will
+     // invoke the handler and will store the configuration for
+     // the configuration session when the handler returns success.
+     // Since this configuration is partial we just pretend to
+     // parse it and always return success. The function that
+     // initiates the session must get the configuration on its
+     // own using getFullConfig.
+     return (isc::config::createAnswer(0, "Configuration accepted."));
+ }
+ 
  ConstElementPtr
  ControlledDhcpv6Srv::dhcp6ConfigHandler(ConstElementPtr new_config) {
-     LOG_DEBUG(dhcp6_logger, DBG_DHCP6_COMMAND, DHCP6_CONFIG_UPDATE)
-               .arg(new_config->str());
  
-     if (server_) {
-         return (configureDhcp6Server(*server_, new_config));
+     if (!server_ || !server_->config_session_) {
+         // That should never happen as we install config_handler
+         // after we instantiate the server.
+         ConstElementPtr answer =
+             isc::config::createAnswer(1, "Configuration rejected,"
+                                       " server is during startup/shutdown phase.");
+         return (answer);
      }
  
-     // That should never happen as we install config_handler after we instantiate
-     // the server.
-     ConstElementPtr answer = isc::config::createAnswer(1,
-            "Configuration rejected, server is during startup/shutdown phase.");
-     return (answer);
+     // The configuration passed to this handler function is partial.
+     // In other words, it just includes the values being modified.
+     // In the same time, there are dependencies between various
+     // DHCP configuration parsers. For example: the option value can
+     // be set if the definition of this option is set. If someone removes
+     // an existing option definition then the partial configuration that
+     // removes that definition is triggered while a relevant option value
+     // may remain configured. This eventually results in the DHCP server
+     // configuration being in the inconsistent state.
+     // In order to work around this problem we need to merge the new
+     // configuration with the existing (full) configuration.
+ 
+     // Let's create a new object that will hold the merged configuration.
+     boost::shared_ptr<MapElement> merged_config(new MapElement());
+     // Let's get the existing configuration.
+     ConstElementPtr full_config = server_->config_session_->getFullConfig();
+     // The full_config and merged_config should be always non-NULL
+     // but to provide some level of exception safety we check that they
+     // really are (in case we go out of memory).
+     if (full_config && merged_config) {
+         merged_config->setValue(full_config->mapValue());
+ 
+         // Merge an existing and new configuration.
+         isc::data::merge(merged_config, new_config);
+         LOG_DEBUG(dhcp6_logger, DBG_DHCP6_COMMAND, DHCP6_CONFIG_UPDATE)
+             .arg(merged_config->str());
+     }
+ 
+     // Configure the server.
+     return (configureDhcp6Server(*server_, merged_config));
  }
  
  ConstElementPtr

diff --cc src/bin/dhcp6/ctrl_dhcp6_srv.h
Simple merge

diff --cc src/bin/dhcp6/dhcp6.spec
Simple merge

diff --cc src/bin/dhcp6/dhcp6_srv.cc
Simple merge

diff --cc src/bin/dhcp6/tests/config_parser_unittest.cc
Simple merge

diff --cc src/lib/dhcp/libdhcp++.cc
Simple merge

diff --cc src/lib/dhcp/option_custom.h
Simple merge

diff --cc src/lib/dhcp/option_definition.cc
Simple merge

diff --cc src/lib/dhcp/tests/libdhcp++_unittest.cc
Simple merge