ng_tee(4)

NAME

ng_tee - netgraph ``tee'' node type

SYNOPSIS

#include <sys/types.h>
#include <netgraph/ng_tee.h>

DESCRIPTION

The tee node type has a purpose similar to the tee(1) com

mand. Tee nodes
are useful for debugging or ``snooping'' on a connection be

tween two netgraph nodes. Tee nodes have four hooks, right, left,

right2left, and
left2right. All data received on right is sent unmodified

to both hooks
left and right2left. Similarly, all data received on left

is sent unmodified to both right and left2right.

Packets may also be received on right2left and left2right;

if so, they
are forwarded unchanged out hooks right and left, respec

tively.

HOOKS

This node type supports the following hooks:

right The connection to the node on the right.

left The connection to the node on the left.

right2left Tap for right to left traffic.

left2right Tap for left to right traffic.

CONTROL MESSAGES

This node type supports the generic control messages, plus

the following.

NGM_TEE_GET_STATS

Get statistics, returned as a struct ng_tee_stats.

NGM_TEE_CLR_STATS

Clear statistics.

SHUTDOWN

This node shuts down upon receipt of an NGM_SHUTDOWN control

message, or
when all hooks have been disconnected. If both right and

left hooks are
present, node removes itself from the chain gently, connect

ing right and
left together.

SEE ALSO

tee(1), netgraph(4), ngctl(8)

HISTORY

The ng_tee node type was implemented in FreeBSD 4.0.

AUTHORS

Julian Elischer <julian@FreeBSD.org>

BSD May 28, 2004

BSD