nghook(8)
NAME
nghook - connect to a netgraph(4) node
SYNOPSIS
nghook [-adlnSs] [-m msg] path [hookname] nghook -e [-n] [-m msg] path hookname program [args ...]
DESCRIPTION
- 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 remain - ing 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 sent to the node be - fore the loop
is entered. The nghook utility exits when EOF is detected - on standard
input in this case. - The options are as follows:
- -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
once. - -n Do not attempt to read any data from standard input.
- The nghook
- utility will continue reading from the node until
- stopped by a
signal. - -S Use file descriptor 0 for output instead of the de
- fault 1.
- -s Use file descriptor 1 for input instead of the de
- fault 0.
SEE ALSO
netgraph(3), netgraph(4), ngctl(8)
HISTORY
- The netgraph system was designed and first implemented at
- Whistle Communications, Inc. in a version of FreeBSD 2.2 customized for
- the Whistle
InterJet.
AUTHORS
Archie Cobbs <archie@whistle.com>
BUGS
- Although all input is read in unbuffered mode, there is no
- way to control
the packetization of the input. - If the node sends a response to a message (specified by -m),
- this
response is lost. - BSD October 24, 2003