DHCPCD-RUN-HOOKS(8) | System Manager's Manual | DHCPCD-RUN-HOOKS(8) |
NAME
dhcpcd-run-hooks
—
DHCP client configuration script
DESCRIPTION
dhcpcd-run-hooks
is used by
dhcpcd(8) to run any system and
user defined hook scripts. System hook scripts are found in
/usr/lib/dhcpcd/dhcpcd-hooks and the user defined
hooks are /etc/dhcpcd.enter-hook. and
/etc/dhcpcd.exit-hook. The default install supplies
hook scripts for configuring /etc/resolv.conf and
the hostname. Your distribution may have included other hook scripts to say
configure ntp or ypbind. A test hook is also supplied that simply echos the
dhcp variables to the console from DISCOVER message.
The hooks scripts are loaded into the current shell rather than
executed in their own process. This allows each hook script, such as
/etc/dhcpcd.enter-hook to customise environment
variables or provide alternative functions to hooks further down the chain.
As such, using the shell builtins exit
,
exec
or similar will cause
dhcpcd-run-hooks
to exit at that point.
Each time dhcpcd-run-hooks
is invoked,
$interface
is set to the interface that
dhcpcd
is run on and $reason
is set to the reason why dhcpcd-run-hooks
was
invoked. DHCP information to be configured is held in variables starting
with the word new_ and old DHCP information to be removed is held in
variables starting with the word old_. dhcpcd
can
display the full list of variables it knows about by using the
-V
, --variables
argument.
Here's a list of reasons why
dhcpcd-run-hooks
could be invoked:
PREINIT
- dhcpcd is starting up and any pre-initialisation required should be performed now.
CARRIER
- dhcpcd has detected the carrier is up. This is generally just a notification and no action need be taken.
NOCARRIER
- dhcpcd lost the carrier. The cable may have been unplugged or association to the wireless point lost.
NOCARRIER_ROAMING
- dhcpcd lost the carrier but the interface configuration is persisted. The OS has to support wireless roaming or IP Persistence for this to happen.
INFORM
|INFORM6
- dhcpcd informed a DHCP server about its address and obtained other configuration details.
BOUND
|BOUND6
- dhcpcd obtained a new lease from a DHCP server.
RENEW
|RENEW6
- dhcpcd renewed its lease.
REBIND
|REBIND6
- dhcpcd has rebound to a new DHCP server.
REBOOT
|REBOOT6
- dhcpcd successfully requested a lease from a DHCP server.
DELEGATED6
- dhcpcd assigned a delegated prefix to the interface.
IPV4LL
- dhcpcd obtained an IPV4LL address, or one was removed.
STATIC
- dhcpcd has been configured with a static configuration which has not been obtained from a DHCP server.
3RDPARTY
- dhcpcd is monitoring the interface for a 3rd party to give it an IP address.
TIMEOUT
- dhcpcd failed to contact any DHCP servers but was able to use an old lease.
EXPIRE
|EXPIRE6
- dhcpcd's lease or state expired and it failed to obtain a new one.
NAK
- dhcpcd received a NAK from the DHCP server. This should be treated as EXPIRE.
RECONFIGURE
- dhcpcd has been instructed to reconfigure an interface.
ROUTERADVERT
- dhcpcd has received an IPv6 Router Advertisement, or one has expired.
STOP
|STOP6
- dhcpcd stopped running on the interface.
STOPPED
- dhcpcd has stopped entirely.
DEPARTED
- The interface has been removed.
FAIL
- dhcpcd failed to operate on the interface. This normally happens when dhcpcd does not support the raw interface, which means it cannot work as a DHCP or ZeroConf client. Static configuration and DHCP INFORM is still allowed.
TEST
- dhcpcd received an OFFER from a DHCP server but will not configure the interface. This is primarily used to test the variables are filled correctly for the script to process them.
ENVIRONMENT
dhcpcd
will clear the environment
variables aside from $PATH
. The following variables
will then be set, along with any protocol supplied ones.
$interface
- the name of the interface.
$protocol
- the protocol that triggered the event.
$reason
- as described above.
$pid
- the pid of
dhcpcd
. $ifcarrier
- the link status of
$interface
:unknown
,up
ordown
. $ifmetric
$interface
preference, lower is better.$ifwireless
1 if
$interface
is wireless, otherwise0
.$ifflags
$interface
flags.$ifmtu
$interface
MTU.$ifssid
- the SSID the
interface
is connected to. $interface_order
- A list of interfaces, in order of preference.
$if_up
true
if theinterface
is up, otherwisefalse
. This is more than IFF_UP and may not be equal.$if_down
true
if theinterface
is down, otherwisefalse
. This is more than IFF_UP and may not be equal.$af_waiting
- Address family waiting for, as defined in dhcpcd.conf(5).
$profile
- the name of the profile selected from dhcpcd.conf(5).
$new_delegated_dhcp6_prefix
- space-separated list of delegated prefixes.
FILES
When dhcpcd-run-hooks
runs, it loads
/etc/dhcpcd.enter-hook, any scripts found in
/usr/lib/dhcpcd/dhcpcd-hooks in lexical order, then
finally /etc/dhcpcd.exit-hook.
SEE ALSO
AUTHORS
Roy Marples <roy@marples.name>
BUGS
Please report them to https://roy.marples.name/projects/dhcpcd
SECURITY CONSIDERATIONS
dhcpcd
will validate the content of each
option against its encoding. For string, ascii, raw or binhex encoding it's
up to the user to validate it for the intended purpose.
When used in a shell script, each variable must be quoted correctly.
August 31, 2022 | Linux 6.10.2-arch1-1 |