.\" Copyright (c) 2005 Gleb Smirnoff
.\" All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\"    notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in the
.\"    documentation and/or other materials provided with the distribution.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
.Dd March 2, 2010
.Dt NG_IPFW 4
.Os
.Sh NAME
.Nm ng_ipfw
.Nd interface between netgraph and IP firewall
.Sh SYNOPSIS
.In netinet/ip_var.h
.In netgraph/ng_ipfw.h
.Sh DESCRIPTION
The
.Nm ipfw
node implements interface between
.Xr ipfw 4
and
.Xr netgraph 4
subsystems.
.Sh HOOKS
The
.Nm ipfw
node supports an arbitrary number of hooks,
which must be named using only numeric characters.
.Sh OPERATION
Once the
.Nm
module is loaded into the kernel, a single node named
.Va ipfw
is automatically created.
No more
.Nm ipfw
nodes can be created.
Once destroyed, the only way to recreate the node is to reload the
.Nm
module.
.Pp
Packets can be injected into
.Xr netgraph 4
using either the
.Cm netgraph
or
.Cm ngtee
commands of the
.Xr ipfw 8
utility.
These commands require a numeric cookie to be supplied as an argument.
Packets are sent out of the hook whose name equals the cookie value.
If no hook matches, packets are discarded.
Packets injected via the
.Cm netgraph
command are tagged with
.Vt "struct ipfw_rule_ref" .
This tag contains information that helps the packet to re-enter
.Xr ipfw 4
processing, should the packet come back from
.Xr netgraph 4
to
.Xr ipfw 4 .
.Pp
Packets received by a node from
.Xr netgraph 4
subsystem must be tagged with
.Vt "struct ipfw_rule_ref"
tag.
Packets re-enter IP firewall processing at the next rule.
If no tag is supplied, packets are discarded.
.Sh CONTROL MESSAGES
This node type supports only the generic control messages.
.Sh SHUTDOWN
This node shuts down upon receipt of a
.Dv NGM_SHUTDOWN
control message.
Do not do this, since the new
.Nm ipfw
node can only be created by reloading the
.Nm
module.
.Sh SEE ALSO
.Xr ipfw 4 ,
.Xr netgraph 4 ,
.Xr ipfw 8 ,
.Xr mbuf_tags 9
.Sh HISTORY
The
.Nm ipfw
node type was implemented in
.Fx 6.0 .
.Sh AUTHORS
The
.Nm ipfw
node was written by
.An Gleb Smirnoff Aq Mt glebius@FreeBSD.org .