udhcp client (udhcpc)--------------------The udhcp client negotiates a lease with the DHCP server and notifiesa set of scripts when a leases is obtained or lost.command line options-------------------The command line options for the udhcp client are:-c, --clientid=CLIENTID         Client identifier-H, --hostname=HOSTNAME         Client hostname-h,                             Alias for -H-F, --fqdn=FQDN                 Client fully qualified domain name-f, --foreground                Do not fork after getting lease-b, --background                Fork to background if lease cannot be                                immediately negotiated.-i, --interface=INTERFACE       Interface to use (default: eth0)-n, --now                       Exit with failure if lease cannot be                                immediately negotiated.-p, --pidfile=file              Store process ID of daemon in file-q, --quit                      Quit after obtaining lease-r, --request=IP                IP address to request (default: none)-s, --script=file               Run file at dhcp events (default:                                /usr/share/udhcpc/default.script)-v, --version                   Display versionIf the requested IP address cannot be obtained, the client accepts theaddress that the server offers.udhcp client scripts-------------------When an event occurs, udhcpc calls the action script. udhcpc never doesany configuration of the network interface itself, but instead relies ona set of scripts. The script by default is/usr/share/udhcpc/default.script but this can be changed via the commandline arguments. The three possible arguments to the script are:	deconfig: This argument is used when udhcpc starts, and	when a leases is lost. The script must put the interface in an	up, but deconfigured state, ie: ifconfig $interface 0.0.0.0.	bound: This argument is used when udhcpc moves from an	unbound, to a bound state. All of the paramaters are set in	enviromental variables, The script should configure the interface,	and set any other relavent parameters (default gateway, dns server,	etc).	renew: This argument is used when a DHCP lease is renewed. All of	the paramaters are set in enviromental variables. This argument is	used when the interface is already configured, so the IP address,	will not change, however, the other DHCP paramaters, such as the	default gateway, subnet mask, and dns server may change.	nak: This argument is used with udhcpc receives a NAK message.	The script with the deconfig argument will be called directly	afterwards, so no changes to the network interface are neccessary.	This hook is provided for purely informational purposes (the	message option may contain a reason for the NAK).The paramaters for enviromental variables are as follows:	$HOME		- The set $HOME env or "/"	$PATH		- the set $PATH env or "/bin:/usr/bin:/sbin:/usr/sbin"	$1		- What action the script should perform	interface	- The interface this was obtained on	ip		- The obtained IP	mask		- The number of bits in the netmask (ie: 24)	siaddr		- The bootp next server option	sname		- The bootp server name option	boot_file	- The bootp boot file option	subnet		- The assigend subnet mask	timezone	- Offset in seconds from UTC	router		- A list of routers	timesvr		- A list of time servers	namesvr		- A list of IEN 116 name servers	dns		- A list of DNS server	logsvr		- A list of MIT-LCS UDP log servers	cookiesvr	- A list of RFC 865 cookie servers	lprsvr		- A list of LPR servers	hostname	- The assigned hostname	bootsize	- The length in 512 octect blocks of the bootfile	domain		- The domain name of the network	swapsvr		- The IP address of the client's swap server	rootpath	- The path name of the client's root disk	ipttl		- The TTL to use for this network	mtu		- The MTU to use for this network	broadcast	- The broadcast address for this network	ntpsrv		- A list of NTP servers	wins		- A list of WINS servers	lease		- The lease time, in seconds	dhcptype	- DHCP message type (safely ignored)	serverid	- The IP of the server	message		- Reason for a DHCPNAK	tftp		- The TFTP server name	bootfile	- The bootfile nameadditional options are easily added in options.c.note on udhcpc's random seed---------------------------udhcpc will seed its random number generator (used for generating xid's)by reading /dev/urandom. If you have a lot of embedded systems on the samenetwork, with no entropy, you can either seed /dev/urandom by a method ofyour own, or doing the following on startup:ifconfig eth0 > /dev/urandomin order to seed /dev/urandom with some data (mac address) unique to yoursystem. If reading /dev/urandom fails, udhcpc will fall back to its oldbehavior of seeding with time(0).signals accepted by udhcpc-------------------------udhcpc also responds to SIGUSR1 and SIGUSR2. SIGUSR1 will force a renew state,and SIGUSR2 will force a release of the current lease, and cause udhcpc togo into an inactive state (until it is killed, or receives a SIGUSR1). You donot need to sleep between sending signals, as signals received are processedsequencially in the order they are received.compile time options-------------------options.c contains a set of dhcp options for the client:	name[10]: The name of the option as it will appear in scripts	flags: The type of option, as well as if it will be requested	by the client (OPTION_REQ)	code: The DHCP code for this option