IFSTATED.CONF(5) OpenBSD Programmer's Manual IFSTATED.CONF(5)NAMEifstated.conf - Interface State daemon configuration file
DESCRIPTION
The ifstated(8) daemon runs commands in response to network state
changes, which it determines by monitoring interface link state or
running external tests. ifstated.conf is the configuration file for this
daemon.
SECTIONS
The ifstated.conf config file is divided into three main sections.
Global Configuration
Global settings for ifstated(8).
Macros
User-defined variables may be defined and used later, simplifying
configuration. Macros must be defined before they are referenced
in ifstated.conf.
State Definitions
Definitions of states and transitions.
GLOBAL CONFIGURATION
init-state state
Set the initial state to state instead of using the first state
defined.
MACROS
Macros can be defined that will later be expanded in context. Macro
names may not be reserved words like, for example state or run. Macros
are referenced with a shell-like notation as $macro. Macros are usually
used to define tests for state transitions like interface link state or
external tests.
Currently an interface can have three different link states:
up The physical link of the interface is up. For carp(4)
interfaces this equals the master state.
down The physical link of the interface is down. For carp(4)
interfaces this equals the backup state.
unknown The physical link of the interface is unknown. This is because
the interface driver does not provide information of the
physical link state. For carp(4) interfaces this equals the
init state.
In contrast to link state tests, external tests must be run periodically
to evaluate their status. The frequency at which an external test is run
has to be set with the every keyword.
For example:
carp_up = "carp0.link.up && carp1.link.up"
net = '( "ping -q -c 1 -w 1 192.168.0.1 > /dev/null" every 10 && \
"ping -q -c 1 -w 1 192.168.0.2 > /dev/null" every 10 )'
TESTS AND EVENTSifstated(8) delegates the process of testing to libevent which associates
a value with every test, in this case true or false. Whenever the value
of a test associated with the current state changes, an event is
triggered and the state's body is processed.
STATE DEFINITIONSifstated(8) operates on a finite state machine with states and
transitions.
Each state consists of an init block and a body. The init block is used
to initialise the state and is executed each time the state is entered.
The body of a state is only executed when that state is the current state
and an event occurs.
The action taken within a certain state is typically made dependent on
the evaluation of one or more if statements. Possible actions include
executing commands using the run statement, or triggering a state
transition with the set-state keyword. It is also possible to write
multiple nested if blocks.
For example:
state one {
init {
run "ifconfig carp0 advskew 10"
run "ifconfig carp1 advskew 10"
}
if ! $net
set-state two
if ! $carp_up {
run "ifconfig carp0 advskew 254"
run "ifconfig carp1 advskew 254"
set-state three
}
}
GRAMMAR
Syntax for ifstated.conf in BNF:
grammar = entry grammar | entry
entry = global_config | varset | action | state
global_config = initstate
initstate = "init-state" string
varset = string "=" string
action_list = action [ action_list ]
action = "run" string | "set-state" string |
"if" expr action_block
action_block = "{" action_list "}" | action
expr = "!" expr | expr "&&" expr | expr "||" expr | term
term = if_test | ext_test | "(" expr ")"
if_test = string ".link." ( "up" | "down" | "unknown" )
ext_test = string "every" number
state = "state" string "{" stateopt_list "}"
stateopt_list = stateopt [ stateopt_list ]
stateopt = init | action
init = "init" action_block
FILES
/etc/ifstated.conf ifstated(8) configuration file
SEE ALSOcarp(4), pf(4), ifstated(8)HISTORY
The ifstated.conf file format first appeared in OpenBSD 3.8.
OpenBSD 4.9 October 25, 2007 OpenBSD 4.9
