nghook -- connect to a netgraph(4) node
nghook [-Sadlns] [-m msg] path [hookname]
nghook -e [-n] [-m msg] path hookname program [args...]
The nghook utility creates a ng_socket(4) socket type node and connects
it to hook hookname of the node found at path. If hookname is omitted,
``debug'' is assumed.
If the -e option is given the third argument is interpreted as the path
to a program and this program is executed with the remaining arguments as
its arguments. Before executing the program netgraph messages (specified
by the -m option) are sent to the node. The program is executed with its
standard input (unless closed by -n) and output connected to the hook.
If the -e option is not given all data written to standard input is sent
to the node and all data received from the node is relayed to standard
output. Messages specified with -m are send to the node before the loop
is entered. The nghook utility exits when EOF is detected on standard
input in this case.
The options are as follows:
-S Use file descriptor 0 for output instead of the default 1.
-a Output each packet read in human-readable decoded ASCII form
instead of raw binary.
-d Increase the debugging verbosity level.
-e Execute the program specified by the third argument.
-l Loops all received data back to the hook in addition to writing
it to standard output.
-m msg Before executing the program (in -e mode) send the given ASCII
control message to the node. This option may be given more than
-n Don't attempt to read any data from standard input. The nghook
utility will continue reading from the node until stopped by a
-s Use file descriptor 1 for input instead of the default 0.
Although all input is read in unbuffered mode, there's no way to control
the packetization of the input.
If the node sends a reponse to a message (specified by -m), this response
netgraph(3), netgraph(4), ngctl(8)
The netgraph system was designed and first implemented at Whistle Communications,
Inc. in a version of FreeBSD 2.2 customized for the Whistle
Archie Cobbs <email@example.com>
FreeBSD 5.2.1 January 19, 1999 FreeBSD 5.2.1 [ Back ]