[1555] Implemented configuration parameter to select interfaces for DHCPv4

src/bin/dhcp4/config_parser.cc

@@ -347,7 +347,7 @@ DhcpConfigParser* createGlobalDhcp4ConfigParser(const std::string& config_id) {
         (config_id.compare("rebind-timer") == 0))  {
         parser = new Uint32Parser(config_id, 
                                  globalContext()->uint32_values_);
-    } else if (config_id.compare("interface") == 0) {
+    } else if (config_id.compare("interfaces") == 0) {
         parser = new InterfaceListConfigParser(config_id);
     } else if (config_id.compare("subnet4") == 0) {
         parser = new Subnets4ListConfigParser(config_id);
@@ -397,6 +397,7 @@ configureDhcp4Server(Dhcpv4Srv&, isc::data::ConstElementPtr config_set) {
     ParserCollection independent_parsers;
     ParserPtr subnet_parser;
     ParserPtr option_parser;
+    ParserPtr iface_parser;
 
     // The subnet parsers implement data inheritance by directly
     // accessing global storage. For this reason the global data
@@ -428,6 +429,11 @@ configureDhcp4Server(Dhcpv4Srv&, isc::data::ConstElementPtr config_set) {
                 subnet_parser = parser;
             } else if (config_pair.first == "option-data") {
                 option_parser = parser;
+            } else if (config_pair.first == "interfaces") {
+                // The interface parser is independent from any other
+                // parser and can be run here before any other parsers.
+                iface_parser = parser;
+                parser->build(config_pair.second);
             } else {
                 // Those parsers should be started before other
                 // parsers so we can call build straight away.
@@ -483,6 +489,10 @@ configureDhcp4Server(Dhcpv4Srv&, isc::data::ConstElementPtr config_set) {
             if (subnet_parser) {
                 subnet_parser->commit();
             }
+
+            if (iface_parser) {
+                iface_parser->commit();
+            }
         }
         catch (const isc::Exception& ex) {
             LOG_ERROR(dhcp4_logger, DHCP4_PARSER_COMMIT_FAIL).arg(ex.what());

src/bin/dhcp4/dhcp4.spec

@@ -3,7 +3,7 @@
     "module_name": "Dhcp4",
     "module_description": "DHCPv4 server daemon",
     "config_data": [
-      { "item_name": "interface",
+      { "item_name": "interfaces",
         "item_type": "list",
         "item_optional": false,
         "item_default": [ "all" ],

src/bin/dhcp4/tests/config_parser_unittest.cc

@@ -51,6 +51,7 @@ public:
         // deal with sockets here, just check if configuration handling
         // is sane.
         srv_.reset(new Dhcpv4Srv(0));
+        CfgMgr::instance().deleteActiveIfaces();
     }
 
     // Checks if global parameter of name have expected_value
@@ -138,7 +139,7 @@ public:
     /// describing an option.
     std::string createConfigWithOption(const std::map<std::string, std::string>& params) {
         std::ostringstream stream;
-        stream << "{ \"interface\": [ \"all\" ],"
+        stream << "{ \"interfaces\": [ \"all\" ],"
             "\"rebind-timer\": 2000, "
             "\"renew-timer\": 1000, "
             "\"subnet4\": [ { "
@@ -245,7 +246,7 @@ public:
     void resetConfiguration() {
         ConstElementPtr status;
 
-        string config = "{ \"interface\": [ \"all\" ],"
+        string config = "{ \"interfaces\": [ \"all\" ],"
             "\"rebind-timer\": 2000, "
             "\"renew-timer\": 1000, "
             "\"valid-lifetime\": 4000, "
@@ -322,7 +323,7 @@ TEST_F(Dhcp4ParserTest, emptySubnet) {
     ConstElementPtr status;
 
     EXPECT_NO_THROW(status = configureDhcp4Server(*srv_,
-                    Element::fromJSON("{ \"interface\": [ \"all\" ],"
+                    Element::fromJSON("{ \"interfaces\": [ \"all\" ],"
                                       "\"rebind-timer\": 2000, "
                                       "\"renew-timer\": 1000, "
                                       "\"subnet4\": [  ], "
@@ -342,7 +343,7 @@ TEST_F(Dhcp4ParserTest, subnetGlobalDefaults) {
 
     ConstElementPtr status;
 
-    string config = "{ \"interface\": [ \"all\" ],"
+    string config = "{ \"interfaces\": [ \"all\" ],"
         "\"rebind-timer\": 2000, "
         "\"renew-timer\": 1000, "
         "\"subnet4\": [ { "
@@ -372,7 +373,7 @@ TEST_F(Dhcp4ParserTest, subnetLocal) {
 
     ConstElementPtr status;
 
-    string config = "{ \"interface\": [ \"all\" ],"
+    string config = "{ \"interfaces\": [ \"all\" ],"
         "\"rebind-timer\": 2000, "
         "\"renew-timer\": 1000, "
         "\"subnet4\": [ { "
@@ -403,7 +404,7 @@ TEST_F(Dhcp4ParserTest, poolOutOfSubnet) {
 
     ConstElementPtr status;
 
-    string config = "{ \"interface\": [ \"all\" ],"
+    string config = "{ \"interfaces\": [ \"all\" ],"
         "\"rebind-timer\": 2000, "
         "\"renew-timer\": 1000, "
         "\"subnet4\": [ { "
@@ -427,7 +428,7 @@ TEST_F(Dhcp4ParserTest, poolPrefixLen) {
 
     ConstElementPtr status;
 
-    string config = "{ \"interface\": [ \"all\" ],"
+    string config = "{ \"interfaces\": [ \"all\" ],"
         "\"rebind-timer\": 2000, "
         "\"renew-timer\": 1000, "
         "\"subnet4\": [ { "
@@ -949,7 +950,7 @@ TEST_F(Dhcp4ParserTest, optionStandardDefOverride) {
 // configuration does not include options configuration.
 TEST_F(Dhcp4ParserTest, optionDataDefaults) {
     ConstElementPtr x;
-    string config = "{ \"interface\": [ \"all\" ],"
+    string config = "{ \"interfaces\": [ \"all\" ],"
         "\"rebind-timer\": 2000,"
         "\"renew-timer\": 1000,"
         "\"option-data\": [ {"
@@ -1022,7 +1023,7 @@ TEST_F(Dhcp4ParserTest, optionDataTwoSpaces) {
     // The definition is not required for the option that
     // belongs to the 'dhcp4' option space as it is the
     // standard option.
-    string config = "{ \"interface\": [ \"all\" ],"
+    string config = "{ \"interfaces\": [ \"all\" ],"
         "\"rebind-timer\": 2000,"
         "\"renew-timer\": 1000,"
         "\"option-data\": [ {"
@@ -1100,7 +1101,7 @@ TEST_F(Dhcp4ParserTest, optionDataEncapsulate) {
     // at the very end (when all other parameters are configured).
 
     // Starting stage 1. Configure sub-options and their definitions.
-    string config = "{ \"interface\": [ \"all\" ],"
+    string config = "{ \"interfaces\": [ \"all\" ],"
         "\"rebind-timer\": 2000,"
         "\"renew-timer\": 1000,"
         "\"option-data\": [ {"
@@ -1149,7 +1150,7 @@ TEST_F(Dhcp4ParserTest, optionDataEncapsulate) {
     // the configuration from the stage 2 is repeated because BIND
     // configuration manager sends whole configuration for the lists
     // where at least one element is being modified or added.
-    config = "{ \"interface\": [ \"all\" ],"
+    config = "{ \"interfaces\": [ \"all\" ],"
         "\"rebind-timer\": 2000,"
         "\"renew-timer\": 1000,"
         "\"option-data\": [ {"
@@ -1245,7 +1246,7 @@ TEST_F(Dhcp4ParserTest, optionDataEncapsulate) {
 // option setting.
 TEST_F(Dhcp4ParserTest, optionDataInSingleSubnet) {
     ConstElementPtr x;
-    string config = "{ \"interface\": [ \"all\" ],"
+    string config = "{ \"interfaces\": [ \"all\" ],"
         "\"rebind-timer\": 2000, "
         "\"renew-timer\": 1000, "
         "\"option-data\": [ {"
@@ -1317,7 +1318,7 @@ TEST_F(Dhcp4ParserTest, optionDataInSingleSubnet) {
 // for multiple subnets.
 TEST_F(Dhcp4ParserTest, optionDataInMultipleSubnets) {
     ConstElementPtr x;
-    string config = "{ \"interface\": [ \"all\" ],"
+    string config = "{ \"interfaces\": [ \"all\" ],"
         "\"rebind-timer\": 2000, "
         "\"renew-timer\": 1000, "
         "\"subnet4\": [ { "
@@ -1597,7 +1598,7 @@ TEST_F(Dhcp4ParserTest, stdOptionDataEncapsulate) {
     // In the first stahe we create definitions of suboptions
     // that we will add to the base option.
     // Let's create some dummy options: foo and foo2.
-    string config = "{ \"interface\": [ \"all\" ],"
+    string config = "{ \"interfaces\": [ \"all\" ],"
         "\"rebind-timer\": 2000,"
         "\"renew-timer\": 1000,"
         "\"option-data\": [ {"
@@ -1650,7 +1651,7 @@ TEST_F(Dhcp4ParserTest, stdOptionDataEncapsulate) {
     // We add our dummy options to this option space and thus
     // they should be included as sub-options in the 'vendor-opts'
     // option.
-    config = "{ \"interface\": [ \"all\" ],"
+    config = "{ \"interfaces\": [ \"all\" ],"
         "\"rebind-timer\": 2000,"
         "\"renew-timer\": 1000,"
         "\"option-data\": [ {"
@@ -1749,5 +1750,69 @@ TEST_F(Dhcp4ParserTest, stdOptionDataEncapsulate) {
     EXPECT_FALSE(desc.option->getOption(3));
 }
 
+// This test verifies that it is possible to select subset of interfaces
+// on which server should listen.
+TEST_F(Dhcp4ParserTest, selectedInterfaces) {
+    ConstElementPtr x;
+    string config = "{ \"interfaces\": [ \"eth0\", \"eth1\" ],"
+        "\"rebind-timer\": 2000, "
+        "\"renew-timer\": 1000, "
+        "\"valid-lifetime\": 4000 }";
 
-};
+    ElementPtr json = Element::fromJSON(config);
+
+    ConstElementPtr status;
+
+    // Make sure the config manager is clean and there is no hanging
+    // interface configuration.
+    ASSERT_FALSE(CfgMgr::instance().isActiveIface("eth0"));
+    ASSERT_FALSE(CfgMgr::instance().isActiveIface("eth1"));
+    ASSERT_FALSE(CfgMgr::instance().isActiveIface("eth2"));
+
+    // Apply configuration.
+    EXPECT_NO_THROW(status = configureDhcp4Server(*srv_, json));
+    ASSERT_TRUE(status);
+    checkResult(status, 0);
+
+    // eth0 and eth1 were explicitly selected. eth2 was not.
+    EXPECT_TRUE(CfgMgr::instance().isActiveIface("eth0"));
+    EXPECT_TRUE(CfgMgr::instance().isActiveIface("eth1"));
+    EXPECT_FALSE(CfgMgr::instance().isActiveIface("eth2"));
+}
+
+// This test verifies that it is possible to configure the server in such a way
+// that it listens on all interfaces.
+TEST_F(Dhcp4ParserTest, allInterfaces) {
+    ConstElementPtr x;
+    // This configuration specifies two interfaces on which server should listen
+    // but it also includes keyword 'all'. This keyword switches server into the
+    // mode when it listens on all interfaces regardless of what interface names
+    // were specified in the "interfaces" parameter.
+    string config = "{ \"interfaces\": [ \"eth0\",\"all\",\"eth1\" ],"
+        "\"rebind-timer\": 2000, "
+        "\"renew-timer\": 1000, "
+        "\"valid-lifetime\": 4000 }";
+
+    ElementPtr json = Element::fromJSON(config);
+
+    ConstElementPtr status;
+
+    // Make sure there is no old configuration.
+    ASSERT_FALSE(CfgMgr::instance().isActiveIface("eth0"));
+    ASSERT_FALSE(CfgMgr::instance().isActiveIface("eth1"));
+    ASSERT_FALSE(CfgMgr::instance().isActiveIface("eth2"));
+
+    // Apply configuration.
+    EXPECT_NO_THROW(status = configureDhcp4Server(*srv_, json));
+    ASSERT_TRUE(status);
+    checkResult(status, 0);
+
+    // All interfaces should be now active.
+    EXPECT_TRUE(CfgMgr::instance().isActiveIface("eth0"));
+    EXPECT_TRUE(CfgMgr::instance().isActiveIface("eth1"));
+    EXPECT_TRUE(CfgMgr::instance().isActiveIface("eth2"));
+}
+
+
+
+}

src/bin/dhcp6/dhcp6.spec

@@ -3,7 +3,7 @@
     "module_name": "Dhcp6",
     "module_description": "DHCPv6 server daemon",
     "config_data": [
-      { "item_name": "interface",
+      { "item_name": "interfaces",
         "item_type": "list",
         "item_optional": false,
         "item_default": [ "all" ],

src/lib/dhcpsrv/cfgmgr.cc

@@ -266,9 +266,61 @@ std::string CfgMgr::getDataDir() {
     return (datadir_);
 }
 
+void
+CfgMgr::addActiveIface(const std::string& iface) {
+    if (isIfaceListedActive(iface)) {
+        isc_throw(DuplicateListeningIface,
+                  "attempt to add duplicate interface '" << iface << "'"
+                  " to the set of interfaces on which server listens");
+    }
+    LOG_DEBUG(dhcpsrv_logger, DHCPSRV_DBG_TRACE, DHCPSRV_CFGMGR_ADD_IFACE)
+        .arg(iface);
+    active_ifaces_.push_back(iface);
+}
+
+void
+CfgMgr::activateAllIfaces() {
+    LOG_DEBUG(dhcpsrv_logger, DHCPSRV_DBG_TRACE,
+              DHCPSRV_CFGMGR_ALL_IFACES_ACTIVE);
+    all_ifaces_active_ = true;
+}
+
+void
+CfgMgr::deleteActiveIfaces() {
+    LOG_DEBUG(dhcpsrv_logger, DHCPSRV_DBG_TRACE,
+              DHCPSRV_CFGMGR_CLEAR_ACTIVE_IFACES);
+    active_ifaces_.clear();
+    all_ifaces_active_ = false;
+}
+
+bool
+CfgMgr::isActiveIface(const std::string& iface) const {
+
+    // @todo Verify that the interface with the specified name is
+    // present in the system.
+
+    // If all interfaces are marked active, there is no need to check that
+    // the name of this interface has been explicitly listed.
+    if (all_ifaces_active_) {
+        return (true);
+    }
+    return (isIfaceListedActive(iface));
+}
+
+bool
+CfgMgr::isIfaceListedActive(const std::string& iface) const {
+    for (ActiveIfacesCollection::const_iterator it = active_ifaces_.begin();
+         it != active_ifaces_.end(); ++it) {
+        if (iface == *it) {
+            return (true);
+        }
+    }
+    return (false);
+}
 
 CfgMgr::CfgMgr()
-    :datadir_(DHCP_DATA_DIR) {
+    : datadir_(DHCP_DATA_DIR),
+      all_ifaces_active_(false) {
     // DHCP_DATA_DIR must be set set with -DDHCP_DATA_DIR="..." in Makefile.am
     // Note: the definition of DHCP_DATA_DIR needs to include quotation marks
     // See AM_CPPFLAGS definition in Makefile.am

src/lib/dhcpsrv/cfgmgr.h

@@ -30,10 +30,21 @@
 #include <map>
 #include <string>
 #include <vector>
+#include <list>
 
 namespace isc {
 namespace dhcp {
 
+/// @brief Exception thrown when the same interface has been specified twice.
+///
+/// In particular, this exception is thrown when adding interface to the set
+/// of interfaces on which server is supposed to listen.
+class DuplicateListeningIface : public Exception {
+public:
+    DuplicateListeningIface(const char* file, size_t line, const char* what) :
+        isc::Exception(file, line, what) { };
+};
+
 
 /// @brief Configuration Manager
 ///
@@ -237,6 +248,36 @@ public:
     /// @return data directory
     std::string getDataDir();
 
+    /// @brief Adds the name of the interface to the set of interfaces on which
+    /// server should listen.
+    ///
+    /// @param iface A name of the interface being added to the listening set.
+    void addActiveIface(const std::string& iface);
+
+    /// @brief Configures the server to listen on all interfaces.
+    ///
+    /// This function configrues the server to listen on all available
+    /// interfaces regardless of the interfaces specified with
+    /// @c CfgMgr::addListeningInterface.
+    void activateAllIfaces();
+
+    /// @brief Clear the collection of the interfaces that server is configured
+    /// to use to listen for incoming requests.
+    ///
+    /// Apart from clearing the list of interfaces specified with
+    /// @c CfgMgr::addListeningInterface, it also disables listening on all
+    /// interfaces if it has been enabled using @c CfgMgr::listenAllInterfaces.
+    void deleteActiveIfaces();
+
+    /// @brief Check if server is configured to listen on the interface which
+    /// name is specified as an argument to this function.
+    ///
+    /// @param iface A name of the interface to be checked.
+    ///
+    /// @return true if the specified interface belongs to the set of the
+    /// interfaces on which server is configured to listen.
+    bool isActiveIface(const std::string& iface) const;
+
 protected:
 
     /// @brief Protected constructor.
@@ -268,6 +309,20 @@ protected:
 
 private:
 
+    /// @brief Checks if the specified interface is listed as active.
+    ///
+    /// This function searches for the specified interface name on the list of
+    /// active interfaces: @c CfgMgr::active_ifaces_. It does not take into
+    /// account @c CfgMgr::all_ifaces_active_ flag. If this flag is set to true
+    /// but the specified interface does not belong to
+    /// @c CfgMgr::active_ifaces_, it will return false.
+    ///
+    /// @param iface interface name.
+    ///
+    /// @return true if specified interface belongs to
+    /// @c CfgMgr::active_ifaces_.
+    bool isIfaceListedActive(const std::string& iface) const;
+
     /// @brief A collection of option definitions.
     ///
     /// A collection of option definitions that can be accessed
@@ -283,6 +338,16 @@ private:
 
     /// @brief directory where data files (e.g. server-id) are stored
     std::string datadir_;
+
+    /// @name A collection of interface names on which server listens.
+    //@{
+    typedef std::list<std::string> ActiveIfacesCollection;
+    std::list<std::string> active_ifaces_;
+    //@}
+
+    /// A flag which indicates that server should listen on all available
+    /// interfaces.
+    bool all_ifaces_active_;
 };
 
 } // namespace isc::dhcp

src/lib/dhcpsrv/dhcp_parsers.cc

@@ -33,6 +33,10 @@ using namespace isc::data;
 namespace isc {
 namespace dhcp {
 
+namespace {
+const char* ALL_IFACES_KEYWORD = "all";
+}
+
 // *********************** ParserContext  *************************
 
 ParserContext::ParserContext(Option::Universe universe):
@@ -140,9 +144,11 @@ template <> void ValueParser<std::string>::build(ConstElementPtr value) {
 
 // ******************** InterfaceListConfigParser *************************
 
-InterfaceListConfigParser::InterfaceListConfigParser(const std::string& 
+InterfaceListConfigParser::
-                                                     param_name) {
+InterfaceListConfigParser(const std::string& param_name)
-    if (param_name != "interface") {
+    : activate_all_(false),
+      param_name_(param_name) {
+    if (param_name_ != "interfaces") {
         isc_throw(BadValue, "Internal error. Interface configuration "
             "parser called for the wrong parameter: " << param_name);
     }
@@ -150,15 +156,63 @@ InterfaceListConfigParser::InterfaceListConfigParser(const std::string&
 
 void
 InterfaceListConfigParser::build(ConstElementPtr value) {
+    // First, we iterate over all specified entries and add it to the
+    // local container so as we can do some basic validation, e.g. eliminate
+    // duplicates.
     BOOST_FOREACH(ConstElementPtr iface, value->listValue()) {
-        interfaces_.push_back(iface->str());
+        std::string iface_name = iface->stringValue();
+        if (iface_name != ALL_IFACES_KEYWORD) {
+            // Let's eliminate duplicates. We could possibly allow duplicates,
+            // but if someone specified duplicated interface name it is likely
+            // that he mistyped the configuration. Failing here should draw his
+            // attention.
+            if (isIfaceAdded(iface_name)) {
+                isc_throw(isc::dhcp::DhcpConfigError, "duplicate interface"
+                          << " name '" << iface_name << "' specified in '"
+                          << param_name_ << "' configuration parameter");
+            }
+            // @todo check that this interface exists in the system!
+            // The IfaceMgr exposes mechanisms to check this.
+
+            // Add the interface name if ok.
+            interfaces_.push_back(iface_name);
+
+        } else {
+            activate_all_ = true;
+
+        }
     }
 }
 
 void
 InterfaceListConfigParser::commit() {
-    /// @todo: Implement per interface listening. Currently always listening
+    CfgMgr& cfg_mgr = CfgMgr::instance();
-    /// on all interfaces.
+    // Remove active interfaces and clear a flag which marks all interfaces
+    // active
+    cfg_mgr.deleteActiveIfaces();
+
+    if (activate_all_) {
+        // Activate all interfaces. There is not need to add their names
+        // explicitly.
+        cfg_mgr.activateAllIfaces();
+
+    } else {
+        // Explicitly add names of the interfaces which server should listen on.
+        BOOST_FOREACH(std::string iface, interfaces_) {
+            cfg_mgr.addActiveIface(iface);
+        }
+    }
+}
+
+bool
+InterfaceListConfigParser::isIfaceAdded(const std::string& iface) const {
+    for (IfaceListStorage::const_iterator it = interfaces_.begin();
+         it != interfaces_.end(); ++it) {
+        if (iface == *it) {
+            return (true);
+        }
+    }
+    return (false);
 }
 
 // **************************** OptionDataParser *************************

src/lib/dhcpsrv/dhcp_parsers.h

@@ -302,8 +302,23 @@ public:
     virtual void commit();
 
 private:
+    /// @brief Check that specified interface exists in
+    /// @c InterfaceListConfigParser::interfaces_.
+    ///
+    /// @param iface A name of the interface.
+    ///
+    /// @return true if specified interface name was found.
+    bool isIfaceAdded(const std::string& iface) const;
+
     /// contains list of network interfaces
-    std::vector<std::string> interfaces_;
+    typedef std::list<std::string> IfaceListStorage;
+    IfaceListStorage interfaces_;
+
+    // Should server listen on all interfaces.
+    bool activate_all_;
+
+    // Parsed parameter name
+    std::string param_name_;
 };
 
 

src/lib/dhcpsrv/dhcpsrv_messages.mes

@@ -54,6 +54,10 @@ consider reducing the lease lifetime.  In this way, addresses allocated
 to clients that are no longer active on the network will become available
 available sooner.
 
+% DHCPSRV_CFGMGR_ADD_IFACE adding listening interface %1
+A debug message issued when new interface is being added to the collection of
+interfaces on which server listens to DHCP messages.
+
 % DHCPSRV_CFGMGR_ADD_SUBNET4 adding subnet %1
 A debug message reported when the DHCP configuration manager is adding the
 specified IPv4 subnet to its database.
@@ -62,6 +66,16 @@ specified IPv4 subnet to its database.
 A debug message reported when the DHCP configuration manager is adding the
 specified IPv6 subnet to its database.
 
+% DHCPSRV_CFGMGR_ALL_IFACES_ACTIVE enabling listening on all interfaces
+A debug message issued when server is being configured to listen on all
+interfaces.
+
+% DHCPSRV_CFGMGR_CLEAR_ACTIVE_IFACES stop listening on all interfaces
+A debug message issued when configuration manager clears the internal list
+of active interfaces. This doesn't prevent the server from listening to
+the DHCP traffic through open sockets, but will rather be used by Interface
+Manager to select active interfaces when sockets are re-opened.
+
 % DHCPSRV_CFGMGR_DELETE_SUBNET4 deleting all IPv4 subnets
 A debug message noting that the DHCP configuration manager has deleted all IPv4
 subnets in its database.

src/lib/dhcpsrv/tests/cfgmgr_unittest.cc

@@ -165,6 +165,7 @@ public:
         CfgMgr::instance().deleteSubnets4();
         CfgMgr::instance().deleteSubnets6();
         CfgMgr::instance().deleteOptionDefs();
+        CfgMgr::instance().deleteActiveIfaces();
     }
 
     /// @brief generates interface-id option based on provided text
@@ -573,6 +574,50 @@ TEST_F(CfgMgrTest, optionSpace6) {
     // @todo decide if a duplicate vendor space is allowed.
 }
 
+// This test verifies that it is possible to specify interfaces that server
+// should listen on.
+TEST_F(CfgMgrTest, addActiveIface) {
+    CfgMgr& cfg_mgr = CfgMgr::instance();
+
+    cfg_mgr.addActiveIface("eth0");
+    cfg_mgr.addActiveIface("eth1");
+
+    EXPECT_TRUE(cfg_mgr.isActiveIface("eth0"));
+    EXPECT_TRUE(cfg_mgr.isActiveIface("eth1"));
+    EXPECT_FALSE(cfg_mgr.isActiveIface("eth2"));
+
+    cfg_mgr.deleteActiveIfaces();
+
+    EXPECT_FALSE(cfg_mgr.isActiveIface("eth0"));
+    EXPECT_FALSE(cfg_mgr.isActiveIface("eth1"));
+    EXPECT_FALSE(cfg_mgr.isActiveIface("eth2"));
+}
+
+// This test verifies that it is possible to set the flag which configures the
+// server to listen on all interfaces.
+TEST_F(CfgMgrTest, activateAllIfaces) {
+    CfgMgr& cfg_mgr = CfgMgr::instance();
+
+    cfg_mgr.addActiveIface("eth0");
+    cfg_mgr.addActiveIface("eth1");
+
+    ASSERT_TRUE(cfg_mgr.isActiveIface("eth0"));
+    ASSERT_TRUE(cfg_mgr.isActiveIface("eth1"));
+    ASSERT_FALSE(cfg_mgr.isActiveIface("eth2"));
+
+    cfg_mgr.activateAllIfaces();
+
+    EXPECT_TRUE(cfg_mgr.isActiveIface("eth0"));
+    EXPECT_TRUE(cfg_mgr.isActiveIface("eth1"));
+    EXPECT_TRUE(cfg_mgr.isActiveIface("eth2"));
+
+    cfg_mgr.deleteActiveIfaces();
+
+    EXPECT_FALSE(cfg_mgr.isActiveIface("eth0"));
+    EXPECT_FALSE(cfg_mgr.isActiveIface("eth1"));
+    EXPECT_FALSE(cfg_mgr.isActiveIface("eth2"));
+}
+
 // No specific tests for getSubnet6. That method (2 overloaded versions) is tested
 // in Dhcpv6SrvTest.selectSubnetAddr and Dhcpv6SrvTest.selectSubnetIface
 // (see src/bin/dhcp6/tests/dhcp6_srv_unittest.cc)

src/lib/dhcpsrv/tests/dhcp_parsers_unittest.cc

@@ -42,6 +42,7 @@ public:
     /// @brief Constructor
     ///
     DhcpParserTest() {
+        CfgMgr::instance().deleteActiveIfaces();
     }
 };
 
@@ -197,21 +198,52 @@ TEST_F(DhcpParserTest, uint32ParserTest) {
 ///
 /// Verifies that the parser:
 /// 1. Does not allow empty for storage.
-/// 2. Does not allow name other than "interface"
+/// 2. Does not allow name other than "interfaces"
-///
+/// 3. Parses list of interfaces and adds them to CfgMgr
-/// InterfaceListParser doesn't do very much, this test will need to 
+/// 4. Parses 'all' keyword and sets a CfgMgr flag which indicates that
-/// expand once it does.
+///    server will listen on all interfaces.
 TEST_F(DhcpParserTest, interfaceListParserTest) {
 
-    const std::string name = "interface";
+    const std::string name = "interfaces";
 
     // Verify that parser constructor fails if parameter name isn't "interface"
     EXPECT_THROW(InterfaceListConfigParser("bogus_name"), isc::BadValue);
 
-    InterfaceListConfigParser parser(name);
+    boost::scoped_ptr<InterfaceListConfigParser>
+        parser(new InterfaceListConfigParser(name));
     ElementPtr list_element = Element::createList();
     list_element->add(Element::create("eth0"));
     list_element->add(Element::create("eth1"));
+
+    // Make sure there are no interfaces added yet.
+    ASSERT_FALSE(CfgMgr::instance().isActiveIface("eth0"));
+    ASSERT_FALSE(CfgMgr::instance().isActiveIface("eth1"));
+
+    // This should parse the configuration and add eth0 and eth1 to the list
+    // of interfaces that server should listen on.
+    parser->build(list_element);
+    parser->commit();
+
+    // Use CfgMgr instance to check if eth0 and eth1 was added, and that
+    // eth2 was not added.
+    CfgMgr& cfg_mgr = CfgMgr::instance();
+    EXPECT_TRUE(cfg_mgr.isActiveIface("eth0"));
+    EXPECT_TRUE(cfg_mgr.isActiveIface("eth1"));
+    EXPECT_FALSE(cfg_mgr.isActiveIface("eth2"));
+
+    // Add keyword all to the configuration. This should activate all
+    // interfaces, including eth2, even though it has not been explicitly
+    // added.
+    list_element->add(Element::create("all"));
+
+    // Reset parser's state.
+    parser.reset(new InterfaceListConfigParser(name));
+    parser->build(list_element);
+    parser->commit();
+
+    EXPECT_TRUE(cfg_mgr.isActiveIface("eth0"));
+    EXPECT_TRUE(cfg_mgr.isActiveIface("eth1"));
+    EXPECT_TRUE(cfg_mgr.isActiveIface("eth2"));
 }
 
 /// @brief Test Implementation of abstract OptionDataParser class. Allows