[#1695] added support for RAI relay suboption 11 (RAI_OPTION_SERVER_ID_OVERRIDE)

doc/sphinx/arm/dhcp4-srv.rst

@@ -2035,6 +2035,8 @@ to be configured with those options.
    +--------------------+------+----------------------------------------------------------------------+
    | subscriber-id      | 6    | Can be used with flex-id to identify hosts.                          |
    +--------------------+------+----------------------------------------------------------------------+
+   | server-id-override | 11   | If sent by the relay, Kea accepts it as the `server-id`.             |
+   +--------------------+------+----------------------------------------------------------------------+
    | relay-source-port  | 19   | If sent by the relay, Kea sends back its responses to this port.     |
    +--------------------+------+----------------------------------------------------------------------+
 
@@ -6699,28 +6701,27 @@ Supported DHCP Standards
 
 The following standards are currently supported in Kea:
 
--  *BOOTP Vendor Information Extensions*, `RFC
+-  *BOOTP Vendor Information Extensions*, `RFC 1497
-   1497 <https://tools.ietf.org/html/rfc1497>`__: This requires the open
+   <https://tools.ietf.org/html/rfc1497>`__: This requires the open source
-   source BOOTP hook to be loaded. See :ref:`hooks-bootp` for details.
+   BOOTP hook to be loaded. See :ref:`hooks-bootp` for details.
 
--  *Dynamic Host Configuration Protocol*, `RFC
+-  *Dynamic Host Configuration Protocol*, `RFC 2131
-   2131 <https://tools.ietf.org/html/rfc2131>`__: Supported messages are
+   <https://tools.ietf.org/html/rfc2131>`__: Supported messages are
    DHCPDISCOVER (1), DHCPOFFER (2), DHCPREQUEST (3), DHCPRELEASE (7),
    DHCPINFORM (8), DHCPACK (5), and DHCPNAK(6).
 
--  *DHCP Options and BOOTP Vendor Extensions*, `RFC
+-  *DHCP Options and BOOTP Vendor Extensions*, `RFC 2132
-   2132 <https://tools.ietf.org/html/rfc2132>`__: Supported options are
+   <https://tools.ietf.org/html/rfc2132>`__: Supported options are PAD (0),
-   PAD (0), END(255), Message Type(53), DHCP Server Identifier (54),
+   END(255), Message Type(53), DHCP Server Identifier (54), Domain Name (15),
-   Domain Name (15), DNS Servers (6), IP Address Lease Time (51), Subnet
+   DNS Servers (6), IP Address Lease Time (51), Subnet Mask (1), and Routers (3).
-   Mask (1), and Routers (3).
 
--  *The IPv4 Subnet Selection Option for DHCP*, `RFC
+-  *The IPv4 Subnet Selection Option for DHCP*, `RFC 3011
-   3011 <https://tools.ietf.org/html/rfc3011>`__: The subnet-selection option
+   <https://tools.ietf.org/html/rfc3011>`__: The subnet-selection option is
-   is supported; if received in a packet, it is used in the subnet-selection
+   supported; if received in a packet, it is used in the subnet-selection
    process.
 
--  *DHCP Relay Agent Information Option*, `RFC
+-  *DHCP Relay Agent Information Option*, `RFC 3046
-   3046 <https://tools.ietf.org/html/rfc3046>`__: Relay Agent Information,
+   <https://tools.ietf.org/html/rfc3046>`__: Relay Agent Information,
    Circuit ID, and Remote ID options are supported.
 
 -  *Link Selection sub-option for the Relay Agent Option*, `RFC 3527
@@ -6728,45 +6729,47 @@ The following standards are currently supported in Kea:
    is supported.
 
 -  *Vendor-Identifying Vendor Options for Dynamic Host Configuration
-   Protocol version 4*, `RFC
+   Protocol version 4*, `RFC 3925
-   3925 <https://tools.ietf.org/html/rfc3925>`__: The Vendor-Identifying
+   <https://tools.ietf.org/html/rfc3925>`__: The Vendor-Identifying Vendor Class
-   Vendor Class and Vendor-Identifying Vendor-Specific Information
+   and Vendor-Identifying Vendor-Specific Information options are supported.
-   options are supported.
 
--  *Subscriber-ID Suboption for the DHCP Relay Agent Option*, `RFC
+-  *Subscriber-ID Suboption for the DHCP Relay Agent Option*, `RFC 3993
-   3993 <https://tools.ietf.org/html/rfc3993>`__: The Subscriber-ID
+   <https://tools.ietf.org/html/rfc3993>`__: The Subscriber-ID option is
-   option is supported.
+   supported.
 
 -  *The Dynamic Host Configuration Protocol (DHCP) Client Fully
    Qualified Domain Name (FQDN) Option*, `RFC 4702
-   <https://tools.ietf.org/html/rfc4702>`__: The Kea server is able to
+   <https://tools.ietf.org/html/rfc4702>`__: The Kea server is able to handle
-   handle the Client FQDN option. Also, it is able to use the
+   the Client FQDN option. Also, it is able to use the ``kea-dhcp-ddns``
-   ``kea-dhcp-ddns`` component to initiate appropriate DNS Update
+   component to initiate appropriate DNS Update operations.
-   operations.
 
--  *Resolution of Fully Qualified Domain Name (FQDN) Conflicts among Dynamic Host
+-  *Resolution of Fully Qualified Domain Name (FQDN) Conflicts among Dynamic
-   Configuration Protocol (DHCP) Clients*, `RFC 4703
+   Host Configuration Protocol (DHCP) Clients*, `RFC 4703
    <https://tools.ietf.org/html/rfc4703>`__: The DHCPv6 server uses a DHCP-DDNS
    server to resolve conflicts.
 
--  *Client Identifier Option in DHCP Server Replies*, `RFC
+-  *Client Identifier Option in DHCP Server Replies*, `RFC 6842
-   6842 <https://tools.ietf.org/html/rfc6842>`__: The server by default sends
+   <https://tools.ietf.org/html/rfc6842>`__: The server by default sends back
-   back the ``client-id`` option. That capability can be disabled. See :ref:`dhcp4-echo-client-id` for details.
+   the ``client-id`` option. That capability can be disabled. See
+   :ref:`dhcp4-echo-client-id` for details.
 
--  *Generalized UDP Source Port for DHCP Relay*, `RFC 8357
+-  *Generalized UDP Source Port for the DHCP Relay Agent Option*, `RFC 8357
-   <https://tools.ietf.org/html/rfc8357>`__: The Kea server
+   <https://tools.ietf.org/html/rfc8357>`__: The Kea server handles the Relay
-   handles the Relay Agent Information Source Port sub-option in a received
+   Agent Information Source Port sub-option in a received message, remembers the
-   message, remembers the UDP port, and sends back a reply to the same relay
+   UDP port, and sends back a reply to the same relay agent using this UDP port.
-   agent using this UDP port.
 
--  *Captive-Portal Identification in DHCP and Router Advertisements (RAs)*, `RFC 8910
+-  *Captive-Portal Identification in DHCP and Router Advertisements (RAs)*, `RFC
-   <https://tools.ietf.org/html/rfc8910>`__: The Kea server can configure both v4
+   8910 <https://tools.ietf.org/html/rfc8910>`__: The Kea server can configure
-   and v6 versions of the captive portal options.
+   both v4 and v6 versions of the captive portal options.
 
 -  *IPv6-Only Preferred Option for DHCPv4*, `RFC 8925
-   <https://tools.ietf.org/html/rfc8925>`__: The Kea
+   <https://tools.ietf.org/html/rfc8925>`__: The Kea server is able to designate
-   server is able to designate its pools and subnets as IPv6-Only Preferred and send
+   its pools and subnets as IPv6-Only Preferred and send back the
-   back the ``v6-only-preferred`` option to clients that requested it.
+   ``v6-only-preferred`` option to clients that requested it.
+
+-  *Server Identifier Override sub-option for the Relay Agent Option*, `RFC 5107
+   <https://tools.ietf.org/html/rfc5107>`__: The server identifier override
+   sub-option is supported.
 
 Known RFC Violations
 --------------------

src/bin/dhcp4/dhcp4_srv.cc

@@ -3695,6 +3695,14 @@ Dhcpv4Srv::acceptServerId(const Pkt4Ptr& query) const {
         return (false);
     }
 
+    OptionPtr rai_option = query->getOption(DHO_DHCP_AGENT_OPTIONS);
+    if (rai_option) {
+        OptionPtr rai_suboption = rai_option->getOption(RAI_OPTION_SERVER_ID_OVERRIDE);
+        if (rai_suboption && (server_id.toBytes() == rai_suboption->toBinary())) {
+            return (true);
+        }
+    }
+
     // This function iterates over all interfaces on which the
     // server is listening to find the one which has a socket bound
     // to the address carried in the server identifier option.

src/bin/dhcp4/tests/dhcp4_srv_unittest.cc

@@ -2448,7 +2448,7 @@ TEST_F(Dhcpv4SrvTest, acceptServerId) {
     // used by the server. The accepted server ids are the IPv4 addresses
     // configured on the interfaces. The 10.1.2.3 is not configured on
     // any interfaces.
-    OptionCustomPtr other_serverid(new OptionCustom(def, Option::V6));
+    OptionCustomPtr other_serverid(new OptionCustom(def, Option::V4));
     other_serverid->writeAddress(IOAddress("10.1.2.3"));
     pkt->addOption(other_serverid);
     EXPECT_FALSE(srv.acceptServerId(pkt));
@@ -2458,7 +2458,7 @@ TEST_F(Dhcpv4SrvTest, acceptServerId) {
 
     // Add a server id being an IPv4 address configured on eth1 interface.
     // A DHCPv4 message holding this server identifier should be accepted.
-    OptionCustomPtr eth1_serverid(new OptionCustom(def, Option::V6));
+    OptionCustomPtr eth1_serverid(new OptionCustom(def, Option::V4));
     eth1_serverid->writeAddress(IOAddress("192.0.2.3"));
     ASSERT_NO_THROW(pkt->addOption(eth1_serverid));
     EXPECT_TRUE(srv.acceptServerId(pkt));
@@ -2468,7 +2468,7 @@ TEST_F(Dhcpv4SrvTest, acceptServerId) {
 
     // Add a server id being an IPv4 address configured on eth0 interface.
     // A DHCPv4 message holding this server identifier should be accepted.
-    OptionCustomPtr eth0_serverid(new OptionCustom(def, Option::V6));
+    OptionCustomPtr eth0_serverid(new OptionCustom(def, Option::V4));
     eth0_serverid->writeAddress(IOAddress("10.0.0.1"));
     ASSERT_NO_THROW(pkt->addOption(eth0_serverid));
     EXPECT_TRUE(srv.acceptServerId(pkt));
@@ -2478,7 +2478,7 @@ TEST_F(Dhcpv4SrvTest, acceptServerId) {
 
     // Add a server id being an IPv4 address configured on subnet3.
     // A DHCPv4 message holding this server identifier should be accepted.
-    OptionCustomPtr subnet_serverid(new OptionCustom(def, Option::V6));
+    OptionCustomPtr subnet_serverid(new OptionCustom(def, Option::V4));
     subnet_serverid->writeAddress(IOAddress("192.0.3.254"));
     ASSERT_NO_THROW(pkt->addOption(subnet_serverid));
     EXPECT_TRUE(srv.acceptServerId(pkt));
@@ -2488,7 +2488,7 @@ TEST_F(Dhcpv4SrvTest, acceptServerId) {
 
     // Add a server id being an IPv4 address configured on shared network1.
     // A DHCPv4 message holding this server identifier should be accepted.
-    OptionCustomPtr network_serverid(new OptionCustom(def, Option::V6));
+    OptionCustomPtr network_serverid(new OptionCustom(def, Option::V4));
     network_serverid->writeAddress(IOAddress("192.0.4.254"));
     ASSERT_NO_THROW(pkt->addOption(network_serverid));
     EXPECT_TRUE(srv.acceptServerId(pkt));
@@ -2499,7 +2499,7 @@ TEST_F(Dhcpv4SrvTest, acceptServerId) {
     // Add a server id being an IPv4 address configured on client class.
     // A DHCPv4 message holding this server identifier should be accepted.
     Pkt4Ptr pkt_with_classes(new Pkt4(DHCPREQUEST, 1234));
-    OptionCustomPtr class_serverid(new OptionCustom(def, Option::V6));
+    OptionCustomPtr class_serverid(new OptionCustom(def, Option::V4));
     class_serverid->writeAddress(IOAddress("192.0.5.254"));
     ASSERT_NO_THROW(pkt_with_classes->addOption(class_serverid));
     pkt_with_classes->addClass("foo");
@@ -2512,7 +2512,7 @@ TEST_F(Dhcpv4SrvTest, acceptServerId) {
     // The configured class does not define the server id option.
     // A DHCPv4 message holding this server identifier should be accepted.
     Pkt4Ptr pkt_with_classes_option_not_defined(new Pkt4(DHCPREQUEST, 1234));
-    OptionCustomPtr global_serverid(new OptionCustom(def, Option::V6));
+    OptionCustomPtr global_serverid(new OptionCustom(def, Option::V4));
     global_serverid->writeAddress(IOAddress("10.0.0.254"));
     ASSERT_NO_THROW(pkt_with_classes_option_not_defined->addOption(global_serverid));
     pkt_with_classes_option_not_defined->addClass("bar");
@@ -2539,6 +2539,32 @@ TEST_F(Dhcpv4SrvTest, acceptServerId) {
 
     // Remove the server identifier.
     ASSERT_NO_THROW(pkt->delOption(DHO_DHCP_SERVER_IDENTIFIER));
+
+    OptionDefinitionPtr rai_def = LibDHCP::getOptionDef(DHCP4_OPTION_SPACE,
+                                                        DHO_DHCP_AGENT_OPTIONS);
+
+    OptionBuffer override_server_id_buf(IOAddress("10.0.0.128").toBytes());
+
+    // Create RAI option.
+    OptionCustomPtr rai(new OptionCustom(*rai_def, Option::V4));
+    OptionPtr rai_override_server_id(new Option(Option::V4,
+                                                RAI_OPTION_SERVER_ID_OVERRIDE,
+                                                override_server_id_buf));
+    rai->addOption(rai_override_server_id);
+
+    // Add a server id being an IPv4 address matching RAI sub-option 11
+    // (RAI_OPTION_SERVER_ID_OVERRIDE).
+    // A DHCPv4 message holding this server identifier should be accepted.
+    Pkt4Ptr pkt_with_override_server_id(new Pkt4(DHCPREQUEST, 1234));
+    OptionCustomPtr override_serverid(new OptionCustom(def, Option::V4));
+    override_serverid->writeAddress(IOAddress("10.0.0.128"));
+
+    ASSERT_NO_THROW(pkt_with_override_server_id->addOption(override_serverid));
+    ASSERT_NO_THROW(pkt_with_override_server_id->addOption(rai));
+    EXPECT_TRUE(srv.acceptServerId(pkt_with_override_server_id));
+
+    // Remove the server identifier.
+    ASSERT_NO_THROW(pkt_with_override_server_id->delOption(DHO_DHCP_SERVER_IDENTIFIER));
 }
 
 // @todo: Implement tests for rejecting renewals