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) 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(getstats)- Get statistics, returned as a
struct ng_tee_stats. NGM_TEE_CLR_STATS(clrstats)- 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, connecting right and
left together.
SEE ALSO
HISTORY
The ng_tee node type was implemented in
FreeBSD 4.0.
AUTHORS
Julian Elischer <julian@FreeBSD.org>