NAME
ng_tee
—
netgraph ``tee'' node type
SYNOPSIS
#include
<netgraph/tee/ng_tee.h>
DESCRIPTION
The tee
node type has a purpose similar to
the tee(1) command. Tee
nodes are useful for
debugging or “snooping” on a connection between 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
,
respectively.
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 a
NGM_SHUTDOWN
control message, or when all hooks have
been disconnected.
SEE ALSO
HISTORY
The ng_tee
node type was implemented in
FreeBSD 4.0.
AUTHORS
Julian Elischer <julian@FreeBSD.org>