unixdev.net


Switch to SpeakEasy.net DSL

The Modular Manual Browser

Home Page
Manual: (FreeBSD-5.4-RELEASE)
Page:
Section:
Apropos / Subsearch:
optional field

NGHOOK(8)                 BSD System Manager's Manual                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 remaining arguments
     as its arguments.  Before executing, the program Netgraph messages (spec-
     ified 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.

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.

SEE ALSO
     netgraph(3), netgraph(4), ngctl(8)

HISTORY
     The netgraph system was designed and first implemented at Whistle Commu-
     nications, Inc. in a version of FreeBSD 2.2 customized for the Whistle
     InterJet.

AUTHORS
     Archie Cobbs <archieATwhistle.com>

BSD                            October 24, 2003                            BSD