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
Thenghook
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 sent 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:
-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 default 1.
-s
- Use file descriptor 1 for input instead of the default 0.
SEE ALSO
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.