NAME
ng_tee — netgraph ``tee'' node typeSYNOPSIS
#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 anNGM_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
tee(1), netgraph(4), ngctl(8)HISTORY
The ng_tee node type was implemented in FreeBSD 4.0.AUTHORS
Julian Elischer <[email protected]>| May 28, 2004 | Debian |