[master] Merged trac4057 (DHCPv4 Relay Agent Link Selection Option)

src/bin/dhcp4/dhcp4_srv.cc

@@ -292,6 +292,29 @@ Dhcpv4Srv::selectSubnet(const Pkt4Ptr& query) const {
     selector.client_classes_ = query->classes_;
     selector.iface_name_ = query->getIface();
 
+    // If the link-selection sub-option is present, extract its value.
+    // "The link-selection sub-option is used by any DHCP relay agent
+    // that desires to specify a subnet/link for a DHCP client request
+    // that it is relaying but needs the subnet/link specification to
+    // be different from the IP address the DHCP server should use
+    // when communicating with the relay agent." (RFC 3257)
+    OptionPtr rai = query->getOption(DHO_DHCP_AGENT_OPTIONS);
+    if (rai) {
+        OptionCustomPtr rai_custom =
+            boost::dynamic_pointer_cast<OptionCustom>(rai);
+        if (rai_custom) {
+            OptionPtr link_select =
+                rai_custom->getOption(RAI_OPTION_LINK_SELECTION);
+            if (link_select) {
+                OptionBuffer link_select_buf = link_select->getData();
+                if (link_select_buf.size() == sizeof(uint32_t)) {
+                    selector.option_select_ =
+                        IOAddress::fromBytes(AF_INET, &link_select_buf[0]);
+                }
+            }
+        }
+    }
+
     CfgMgr& cfgmgr = CfgMgr::instance();
     subnet = cfgmgr.getCurrentCfg()->getCfgSubnets4()->selectSubnet(selector);
 

src/bin/dhcp4/tests/dhcp4_srv_unittest.cc

@@ -3236,6 +3236,106 @@ TEST_F(Dhcpv4SrvTest, relayOverrideAndClientClass) {
     EXPECT_TRUE(subnet1 == srv_.selectSubnet(dis));
 }
 
+// Checks if a RAI link selection sub-option works as expected
+TEST_F(Dhcpv4SrvTest, relayLinkSelect) {
+
+    // We have 3 subnets defined.
+    string config = "{ \"interfaces-config\": {"
+        "    \"interfaces\": [ \"*\" ]"
+        "},"
+        "\"rebind-timer\": 2000, "
+        "\"renew-timer\": 1000, "
+        "\"subnet4\": [ "
+        "{   \"pools\": [ { \"pool\": \"192.0.2.2 - 192.0.2.100\" } ],"
+        "    \"relay\": { "
+        "        \"ip-address\": \"192.0.5.1\""
+        "    },"
+        "    \"subnet\": \"192.0.2.0/24\" }, "
+        "{   \"pools\": [ { \"pool\": \"192.0.3.1 - 192.0.3.100\" } ],"
+        "    \"subnet\": \"192.0.3.0/24\" }, "
+        "{   \"pools\": [ { \"pool\": \"192.0.4.1 - 192.0.4.100\" } ],"
+        "    \"client-class\": \"foo\", "
+        "    \"subnet\": \"192.0.4.0/24\" } "
+        "],"
+        "\"valid-lifetime\": 4000 }";
+
+    // Use this config to set up the server
+    ASSERT_NO_THROW(configure(config));
+
+    // Let's get the subnet configuration objects
+    const Subnet4Collection* subnets =
+        CfgMgr::instance().getCurrentCfg()->getCfgSubnets4()->getAll();
+    ASSERT_EQ(3, subnets->size());
+
+    // Let's get them for easy reference
+    Subnet4Ptr subnet1 = (*subnets)[0];
+    Subnet4Ptr subnet2 = (*subnets)[1];
+    Subnet4Ptr subnet3 = (*subnets)[2];
+    ASSERT_TRUE(subnet1);
+    ASSERT_TRUE(subnet2);
+    ASSERT_TRUE(subnet3);
+
+    // Let's create a packet.
+    Pkt4Ptr dis = Pkt4Ptr(new Pkt4(DHCPDISCOVER, 1234));
+    dis->setRemoteAddr(IOAddress("192.0.2.1"));
+    dis->setIface("eth0");
+    dis->setHops(1);
+    OptionPtr clientid = generateClientId();
+    dis->addOption(clientid);
+
+    // Let's create a Relay Agent Information option
+    OptionDefinitionPtr rai_def = LibDHCP::getOptionDef(Option::V4,
+                                                        DHO_DHCP_AGENT_OPTIONS);
+    ASSERT_TRUE(rai_def);
+    OptionCustomPtr rai(new OptionCustom(*rai_def, Option::V4));
+    ASSERT_TRUE(rai);
+    IOAddress addr("192.0.3.2");
+    OptionPtr ols(new Option(Option::V4,
+                             RAI_OPTION_LINK_SELECTION,
+                             addr.toBytes()));
+    ASSERT_TRUE(ols);
+    rai->addOption(ols);
+
+    // This is just a sanity check, we're using regular method: ciaddr 192.0.3.1
+    // belongs to the second subnet, so it is selected
+    dis->setGiaddr(IOAddress("192.0.3.1"));
+    EXPECT_TRUE(subnet2 == srv_.selectSubnet(dis));
+
+    // Setup a relay override for the first subnet as it has a high precedence
+    dis->setGiaddr(IOAddress("192.0.5.1"));
+    EXPECT_TRUE(subnet1 == srv_.selectSubnet(dis));
+
+    // Put a RAI to select back the second subnet as it has
+    // the highest precedence
+    dis->addOption(rai);
+    EXPECT_TRUE(subnet2 == srv_.selectSubnet(dis));
+
+    // Check client-classification still applies
+    IOAddress addr_foo("192.0.4.2");
+    ols.reset(new Option(Option::V4, RAI_OPTION_LINK_SELECTION,
+                         addr_foo.toBytes()));
+    rai->delOption(RAI_OPTION_LINK_SELECTION);
+    dis->delOption(DHO_DHCP_AGENT_OPTIONS);
+    rai->addOption(ols);
+    dis->addOption(rai);
+    // Note it shall fail (vs. try the next criterion).
+    EXPECT_FALSE(srv_.selectSubnet(dis));
+    // Add the packet to the class and check again: now it shall succeed
+    dis->addClass("foo");
+    EXPECT_TRUE(subnet3 == srv_.selectSubnet(dis));
+
+    // Check it fails with a bad address in the sub-option
+    IOAddress addr_bad("10.0.0.1");
+    ols.reset(new Option(Option::V4, RAI_OPTION_LINK_SELECTION,
+                         addr_bad.toBytes()));
+    rai->delOption(RAI_OPTION_LINK_SELECTION);
+    dis->delOption(DHO_DHCP_AGENT_OPTIONS);
+    rai->addOption(ols);
+    dis->addOption(rai);
+    EXPECT_FALSE(srv_.selectSubnet(dis));
+
+}
+
 // This test verifies that the direct message is dropped when it has been
 // received by the server via an interface for which there is no subnet
 // configured. It also checks that the message is not dropped (is processed)

src/lib/dhcpsrv/cfg_subnets4.cc

@@ -39,6 +39,12 @@ CfgSubnets4::add(const Subnet4Ptr& subnet) {
 
 Subnet4Ptr
 CfgSubnets4::selectSubnet(const SubnetSelector& selector) const {
+    // First use RAI link select sub-option or subnet select option
+    if (!selector.option_select_.isV4Zero()) {
+        return (selectSubnet(selector.option_select_,
+                             selector.client_classes_));
+    }
+
     // If relayed message has been received, try to match the giaddr with the
     // relay address specified for a subnet. It is also possible that the relay
     // address will not match with any of the relay addresses accross all

src/lib/dhcpsrv/cfg_subnets4.h

@@ -61,6 +61,9 @@ public:
     /// parameters extracted from the client's message using the following
     /// logic.
     ///
+    /// First when link select suboption of relay agent information option
+    /// or subnet select option in this order exists the address is used
+    ///
     /// If the giaddr value is set in the selector it means that the client's
     /// message was relayed. The subnet configuration allows for setting the
     /// relay address for each subnet to indicate that the subnet must be

src/lib/dhcpsrv/subnet_selector.h

@@ -1,4 +1,4 @@
-// Copyright (C) 2014 Internet Systems Consortium, Inc. ("ISC")
+// Copyright (C) 2014-2015 Internet Systems Consortium, Inc. ("ISC")
 //
 // Permission to use, copy, modify, and/or distribute this software for any
 // purpose with or without fee is hereby granted, provided that the above
@@ -35,6 +35,8 @@ struct SubnetSelector {
     asiolink::IOAddress ciaddr_;
     /// @brief giaddr from the client's message.
     asiolink::IOAddress giaddr_;
+    /// @brief RAI link select or subnet select option
+    asiolink::IOAddress option_select_;
     //@}
 
     /// @name DHCPv6 specific parameters.
@@ -60,6 +62,7 @@ struct SubnetSelector {
     SubnetSelector()
         : ciaddr_(asiolink::IOAddress("0.0.0.0")),
           giaddr_(asiolink::IOAddress("0.0.0.0")),
+          option_select_(asiolink::IOAddress("0.0.0.0")),
           interface_id_(),
           first_relay_linkaddr_(asiolink::IOAddress("::")),
           local_address_(asiolink::IOAddress("0.0.0.0")),

src/lib/dhcpsrv/tests/cfg_option_unittest.cc

@@ -132,7 +132,7 @@ TEST(CfgOptionTest, add) {
 }
 
 // This test verifies that two option configurations can be merged.
-TEST(CfgOption, merge) {
+TEST(CfgOptionTest, merge) {
     CfgOption cfg_src;
     CfgOption cfg_dst;
 
@@ -308,7 +308,7 @@ TEST(CfgOptionTest, encapsulate) {
 
 // This test verifies that single option can be retrieved from the configuration
 // using option code and option space.
-TEST(CfgOption, get) {
+TEST(CfgOptionTest, get) {
     CfgOption cfg;
 
     // Add 10 options to a "dhcp6" option space in the subnet.

src/lib/dhcpsrv/tests/cfg_subnets4_unittest.cc

@@ -143,9 +143,46 @@ TEST(CfgSubnets4Test, selectSubnetByClasses) {
     EXPECT_FALSE(cfg.selectSubnet(selector));
 }
 
+// This test verifies the option selection can be used and is only
+// used when present.
+TEST(CfgSubnets4Test, selectSubnetByOptionSelect) {
+    CfgSubnets4 cfg;
+
+    // Create 3 subnets.
+    Subnet4Ptr subnet1(new Subnet4(IOAddress("192.0.2.0"), 26, 1, 2, 3));
+    Subnet4Ptr subnet2(new Subnet4(IOAddress("192.0.2.64"), 26, 1, 2, 3));
+    Subnet4Ptr subnet3(new Subnet4(IOAddress("192.0.2.128"), 26, 1, 2, 3));
+
+    // Add them to the configuration.
+    cfg.add(subnet1);
+    cfg.add(subnet2);
+    cfg.add(subnet3);
+
+    SubnetSelector selector;
+
+    // Check that without option selection something else is used
+    selector.ciaddr_ = IOAddress("192.0.2.5");
+    EXPECT_EQ(subnet1, cfg.selectSubnet(selector));
+
+    // The option selection has precedence
+    selector.option_select_ = IOAddress("192.0.2.130");
+    EXPECT_EQ(subnet3, cfg.selectSubnet(selector));
+
+    // Over relay-info too
+    selector.giaddr_ = IOAddress("10.0.0.1");
+    subnet2->setRelayInfo(IOAddress("10.0.0.1"));
+    EXPECT_EQ(subnet3, cfg.selectSubnet(selector));
+    selector.option_select_ = IOAddress("0.0.0.0");
+    EXPECT_EQ(subnet2, cfg.selectSubnet(selector));
+
+    // Check that a not matching option selection it shall fail
+    selector.option_select_ = IOAddress("10.0.0.1");
+    EXPECT_FALSE(cfg.selectSubnet(selector));
+}
+
 // This test verifies that the relay information can be used to retrieve the
 // subnet.
-TEST(CfgSubnetsTest, selectSubnetByRelayAddress) {
+TEST(CfgSubnets4Test, selectSubnetByRelayAddress) {
     CfgSubnets4 cfg;
 
     // Create 3 subnets.
@@ -184,7 +221,7 @@ TEST(CfgSubnetsTest, selectSubnetByRelayAddress) {
 
 // This test verifies that the subnet can be selected for the client
 // using a source address if the client hasn't set the ciaddr.
-TEST(CfgSubnetsTest, selectSubnetNoCiaddr) {
+TEST(CfgSubnets4Test, selectSubnetNoCiaddr) {
     CfgSubnets4 cfg;
 
     // Create 3 subnets.
@@ -224,7 +261,7 @@ TEST(CfgSubnetsTest, selectSubnetNoCiaddr) {
 
 // This test verifies that the subnet can be selected using an address
 // set on the local interface.
-TEST(CfgSubnetsTest, selectSubnetInterface) {
+TEST(CfgSubnets4Test, selectSubnetInterface) {
     // The IfaceMgrTestConfig object initializes fake interfaces:
     // eth0, eth1 and lo on the configuration manager. The CfgSubnets4
     // object uses addresses assigned to these fake interfaces to
@@ -276,7 +313,7 @@ TEST(CfgSubnetsTest, selectSubnetInterface) {
 
 // Checks that detection of duplicated subnet IDs works as expected. It should
 // not be possible to add two IPv4 subnets holding the same ID.
-TEST(CfgSubnets4, duplication) {
+TEST(CfgSubnets4Test, duplication) {
     CfgSubnets4 cfg;
 
     Subnet4Ptr subnet1(new Subnet4(IOAddress("192.0.2.0"), 26, 1, 2, 3, 123));

src/lib/dhcpsrv/tests/cfg_subnets6_unittest.cc

@@ -337,7 +337,7 @@ TEST(CfgSubnets6Test, selectSubnetByInterfaceIdAndClassify) {
 
 // Checks that detection of duplicated subnet IDs works as expected. It should
 // not be possible to add two IPv6 subnets holding the same ID.
-TEST(CfgSubnets6, duplication) {
+TEST(CfgSubnets6Test, duplication) {
     CfgSubnets6 cfg;
 
     Subnet6Ptr subnet1(new Subnet6(IOAddress("2000::"), 48, 1, 2, 3, 4, 123));

src/lib/dhcpsrv/tests/pool_unittest.cc

@@ -119,7 +119,7 @@ TEST(Pool4Test, unique_id) {
 }
 
 // Simple check if toText returns reasonable values
-TEST(Poo4Test,toText) {
+TEST(Pool4Test,toText) {
     Pool4 pool1(IOAddress("192.0.2.7"), IOAddress("192.0.2.17"));
     EXPECT_EQ("type=V4, 192.0.2.7-192.0.2.17", pool1.toText());