systems. It does however, strive to be fully functional, and RFC
compliant.
-udhcp server (udhcpd)
---------------------
-
-The only command line argument to udhcpd is an optional specifed
-config file. If no config file is specified, udhcpd uses the default
-config file, /etc/udhcpd.conf. Ex:
-
-udhcpd /etc/udhcpd.eth1.conf
-
-The udhcp server employs a number of simple config files:
-
-udhcpd.leases
-------------
-
-The udhcpd.leases behavior is designed for an embedded system. The
-file is written either every auto_time seconds, or when a SIGUSR1
-is received (the auto_time timer restarts if a SIGUSR1 is received).
-If you send a SIGTERM to udhcpd directly after a SIGUSR1, udhcpd will
-finish writing the leases file and wait for the aftermentioned script
-to be executed and finish before quiting, so you do not need to sleep
-between sending signals. When the file is written, a script can be
-optionally called to commit the file to flash. Lease times are stored
-in the file by time remaining in lease (for systems without clock
-that works when there is no power), or by the absolute time that it
-expires in seconds from epoch. In the remainig format, expired leases
-are stored as zero. The file is of the format:
-
-16 byte MAC
-4 byte ip address
-u32 expire time
-16 byte MAC
-4 byte ip address
-u32 expire time
-.
-etc.
-
-example: hexdump udhcpd.leases
-
-0000000 1000 c95a 27d9 0000 0000 0000 0000 0000
-0000010 a8c0 150a 0d00 2d29 5000 23fc 8566 0000
-0000020 0000 0000 0000 0000 a8c0 140a 0d00 4e29
-0000030
-
-
-udhcpd.conf
-----------
-
-The format is fairly simple, there is a sample file with all the
-available options and comments describing them in samples/udhcpd.conf
-
-
-udhcp client (udhcpc)
---------------------
-
-The udhcp client negotiates a lease with the DHCP server and notifies
-a set of scripts when a leases is obtained or lost. The command line
-options for the udhcp client are:
-
--c, --clientid=CLIENTID Client identifier
--H, --hostname=HOSTNAME Client hostname
--h, Alias for -H
--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 version
-
-If the requested IP address cannot be obtained, the client accepts the
-address that the server offers.
-
-When an event occurs, udhcpc calls the action script. The script by
-default is /usr/share/udhcpc/default.script but this can be changed via
-the command line 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 should 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
- 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 name
-
-additional options are easily added in options.c.
-
-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 to
-go into an inactive state (until it is killed, or receives a SIGUSR1). You do
-not need to sleep between sending signals, as signals received are processed
-sequencially in the order they are received.
-
-
compile time options
-------------------
code: The DHCP code for this option
+
busybox drop-in
--------------
udhcp is now a drop-in component for busybox (http://busybox.net).
The only two files udhcp does not provide are config.in and
Makefile.in, so these may need to be updated from time to time.
+
projects / oweals / busybox.git / blobdiff