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>

Debian                                            May 28, 2004                                         NG_TEE(4)