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NG_IPFW(4)		     Kernel Interfaces Manual		      NG_IPFW(4)

NAME
     ng_ipfw -- interface between netgraph and IP firewall

SYNOPSIS
     #include <netgraph/ng_ipfw.h>

DESCRIPTION
     The  ipfw node implements interface between ipfw(4) and netgraph(4) subsys-
     tems.

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 de-
     stroyed, 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.  Pack-
     ets  injected  via the netgraph command are tagged with struct ng_ipfw_tag.
     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).

	 struct ng_ipfw_tag {
		 struct m_tag	 mt;		 /* tag header */
		 struct ip_fw	 *rule; 	 /* matching rule */
		 struct ifnet	 *ifp;		 /* interface, for ip_output */
		 int		 dir;		 /* packet direction */
	 #define NG_IPFW_OUT	 0
	 #define NG_IPFW_IN	 1
		 int		 flags; 	 /* flags, for ip_output() */
	 };

     Packets  received	by  a  node  from netgraph(4) must be tagged with struct
     ng_ipfw_tag 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
     ipfw(4), netgraph(4), ipfw(8), mbuf_tags(9)

HISTORY
     The ipfw node type was implemented in FreeBSD 6.0.

AUTHORS
     The ipfw node was written by Gleb Smirnoff <glebius@FreeBSD.org>.

FreeBSD 6.0			February 5, 2005		      NG_IPFW(4)
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