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
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, 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 〈julian@FreeBSD.org〉