udhcpc 的配置记录

udhcpc scripts
Here's some debian scripts I wrote for
udhcpc
0.9.6.??I wanted to make
it easy to run local scripts for DHCP changes so I created
/etc/udhcpc.d.??All the /usr/share/udhcpc/default.* scripts
have been merged into /etc/udhcpc.d/S50default.??S99local
is an example script that patches resolv.conf and calls
a DNS update script.
? ?
/etc/init.d/
udhcpc
/etc/
udhcpc.script
/etc/udhcpc.d/
S50default
/etc/udhcpc.d/
S99local
? ?
Last modified: Mon Feb??4 10:23:49 PST 2002
单调的分割线
http://udhcp.busybox.net/README.udhcpc
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.
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, --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.
udhcp client scripts
-------------------
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.
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 same
network, with no entropy, you can either seed /dev/urandom by a method of
your own, or doing the following on startup:
ifconfig eth0 > /dev/urandom
in order to seed /dev/urandom with some data (mac address) unique to your
system. If reading /dev/urandom fails, udhcpc will fall back to its old
behavior 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 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
-------------------
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


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