NAME
ng_ipfw —
interface between netgraph and IP
firewall
SYNOPSIS
#include
<netinet/ip_var.h>
#include
<netgraph/ng_ipfw.h>
DESCRIPTION
The ipfw node implements interface between
ipfw(4) and
netgraph(4) subsystems.
HOOKS
The ipfw node supports an arbitrary number
of hooks, which must be named using only numeric characters.
OPERATION
Once the ng_ipfw module is loaded into the
kernel, a single node named ipfw is automatically
created. No more ipfw nodes can be created. Once
destroyed, the only way to recreate the node is to reload the
ng_ipfw module.
Packets can be injected into
netgraph(4) using either the netgraph or
ngtee commands of the
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 netgraph command are tagged with
struct ipfw_rule_ref. This tag contains information
that helps the packet to re-enter
ipfw(4) processing, should the packet come back from
netgraph(4) to
ipfw(4).
Packets received by a node from netgraph(4) subsystem must be tagged with struct ipfw_rule_ref tag. Packets re-enter IP firewall processing at the next rule. If no tag is supplied, packets are discarded.
CONTROL MESSAGES
This node type supports only the generic control messages.
SHUTDOWN
This node shuts down upon receipt of a
NGM_SHUTDOWN control message. Do not do this, since
the new ipfw node can only be created by reloading
the ng_ipfw module.
SEE ALSO
HISTORY
The ipfw node type was implemented in
FreeBSD 6.0.
AUTHORS
The ipfw node was written by
Gleb Smirnoff
<glebius@FreeBSD.org>.