DHCP-User

Compilation dependencies
Getting Started

The DHCP-User was implemented in order to enable the discovery of PoS entities according to the guidelines depicted in the RFC5678. It is a modification of the ”dhclient” software (version 4.2.5), which was extended to support the IEEE 802.21 standard and communicate via MIH protocol.

The DHCP-User has two modes of discovery operations: explicit discovery or bootstrap discovery. In the explicit discovery, the discovery process is initiated by a MIH-User, while at the boostrap discovery the available PoS entities are discovered during the aquisition of IP address.

In the explicit discovery, the discovery process is triggered by the reception of a "MIH_Capability_Discover.indication" message. In the bootstrap discovery, the process is triggered by a "Link_Up.indication" message (which indicates the occurence of a L2 attachement). In both cases the discovered entities are grouped in one single message and are forwarded to the MIHF through a "MIH_Capability_Discover.response" message.

	Note
	The DHCP-User is working only for Linux.

	Note
	ODTONE also provides the DHCP server application, which is an modified version of the "dhcpd" (version 4.2.5) supporting the IEEE 802.21 DHCP options.

Compilation dependencies

Bind9 library
libisc library

Getting Started

Registering with the MIHF
Configuration
Running

Registering with the MIHF

The DHCP-User does not need provide any information during the registration process. To give this entity the discovery role, it must be configured in the MIHF using the following option:

[mihf]
discovery = DHCP

Configuration

DHCP-User Configuration:
    --help                           Display configuration options
    --conf.file arg (=dhcp_usr.conf) Configuration File
    --user.id arg (=DHCP)            MIH User ID
    --conf.port arg (=1234)          Listening Port
    --conf.recv_buff_len arg (=4096) Receive Buffer Length
    --user.ip_version arg (=4)       IP Protocol Version (4/6)
    --user.nic arg                   Interface Info List
    --mihf.ip arg (=127.0.0.1)       MIHF Local Communications IP Address
    --mihf.local_port arg (=1025)    MIHF Local Communications Port

The DHCP-User can be configured based on a set of parameters, which can be configured either using an configuration file or passing them directly in the command line.

For defining the network interfaces that the DHCP-User will manage the user.nic option must be used. It also can only operate DHCPv4 or DHCPv6 at a time, not both. To use both protocols simultaneously, two instances of the DHCP-User are required, one with the user.ip_version option set to 6 and other to 4.

dhclient configuration

The dhclient.conf file contains configuration information for "dhclient", which is the core of our DHCP-User. You must place it on the "/etc/dhclient.conf".

The dhclient.conf file is a free-form ASCII text file. It is parsed by the recursive-descent parser built into dhclient. The file may contain extra tabs and newlines for formatting purposes. Keywords in the file are case-insensitive. Comments may be placed anywhere within the file (except within quotes). Comments begin with the # character and end at the end of the line.

The dhclient.conf file can be used to configure the behaviour of the client in a wide variety of ways: protocol timing, information requested from the server, information required of the server, defaults to use if the server does not provide certain information, values with which to override information provided by the server, or values to prepend or append to information provided by the server. The configuration file can also be preinitialized with addresses to use on networks that don't have DHCP servers.

dhclient.conf example:

# IPv4

request subnet-mask, broadcast-address, time-offset, routers,
		domain-name, domain-name-servers, domain-search, host-name,
		netbios-name-servers, netbios-scope, interface-mtu,
		ntp-servers, option-ipv4-address-mos_ip, option-ipv4-address-mos_fqdn
		;

# IPv6

also request dhcp6.option-ipv6-address-mos;
also request dhcp6.option-fqdn6-address-mos;

	Note
	For more information check the dhclient.conf man pages

dhcpd configuration

The dhcpd.conf file contains configuration information for dhcpd, the Internet Systems Consortium DHCP Server.

The dhcpd.conf file is a free-form ASCII text file. It is parsed by the recursive-descent parser built into dhcpd. The file may contain extra tabs and newlines for formatting purposes. Keywords in the file are case-insensitive. Comments may be placed anywhere within the file (except within quotes). Comments begin with the # character and end at the end of the line.

dhcpd.conf example:

# IPv4

option domain-name "odtone.test";
option domain-name-servers ns1.odtone.test, ns2.odtone.test;

default-lease-time 600;
max-lease-time 7200;
log-facility local7;

subnet 192.168.1.0 netmask 255.255.255.0 {
	    authoritative;
	    range 192.168.1.10 192.168.1.30;
	    option option-ipv4-address-mos.is 10.110.1.1;
	    option option-fqdn-address-mos.is "odtone.test";
}

# IPv6

default-lease-time 600;
max-lease-time 7200;
log-facility local7;
subnet6 2000:aaaa:bbbb:cccc::/64 {
	    # Range for clients
	    range6 2000:aaaa:bbbb:cccc::2 2000:aaaa:bbbb:cccc::20;
	    # Additional options
	    option dhcp6.name-servers fec0:0:0:1::1;
	    option dhcp6.domain-search "domain.example";
	    # Prefix range for delegation to sub-routers
	    prefix6 2001:db8:0:100:: 2001:db8:0:f00:: /56;
	    # Example for a fixed host address
	    host specialclient {
	            host-identifier option dhcp6.client-id 00:01:00:01:4a:1f:ba:e3:60:b9:1f:01:23:45;
	            fixed-address6 2001:db8:0:1::127;
	    }

	    option dhcp6.option-ipv4-address-mos 00:01:00:10:fe:80:00:00:00:00:00:00:02:03:1d:ff:fe:07:15:73 ;
	    option dhcp6.option-fqdn-address-mos 00:01:00:0d:06:6f:64:74:6f:6e:65:04:74:65:73:74:00 ;
}

	Note
	For more information check the dhcpd.conf man pages

Running

Before running the DHCP-User, the local MIHF should already be running. Otherwise, the DHCP-User will try to register with a non-exitent MIHF.