xref: /freebsd/share/man/man4/ng_ipfw.4 (revision 2be1a816b9ff69588e55be0a84cbe2a31efc0f2f)
1.\" Copyright (c) 2005 Gleb Smirnoff
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25.\" $FreeBSD$
26.\"
27.Dd February 5, 2005
28.Dt NG_IPFW 4
29.Os
30.Sh NAME
31.Nm ng_ipfw
32.Nd interface between netgraph and IP firewall
33.Sh SYNOPSIS
34.In netgraph/ng_ipfw.h
35.Sh DESCRIPTION
36The
37.Nm ipfw
38node implements interface between
39.Xr ipfw 4
40and
41.Xr netgraph 4
42subsystems.
43.Sh HOOKS
44The
45.Nm ipfw
46node supports an arbitrary number of hooks,
47which must be named using only numeric characters.
48.Sh OPERATION
49Once the
50.Nm
51module is loaded into the kernel, a single node named
52.Va ipfw
53is automatically created.
54No more
55.Nm ipfw
56nodes can be created.
57Once destroyed, the only way to recreate the node is to reload the
58.Nm
59module.
60.Pp
61Packets can be injected into
62.Xr netgraph 4
63using either the
64.Cm netgraph
65or
66.Cm ngtee
67commands of the
68.Xr ipfw 8
69utility.
70These commands require a numeric cookie to be supplied as an argument.
71Packets are sent out of the hook whose name equals the cookie value.
72If no hook matches, packets are discarded.
73Packets injected via the
74.Cm netgraph
75command are tagged with
76.Vt "struct ng_ipfw_tag" .
77This tag contains information that helps the packet to re-enter
78.Xr ipfw 4
79processing, should the packet come back from
80.Xr netgraph 4
81to
82.Xr ipfw 4 .
83.Bd -literal -offset 4n
84struct ng_ipfw_tag {
85	struct m_tag	mt;		/* tag header */
86	struct ip_fw	*rule;		/* matching rule */
87        struct ifnet	*ifp;		/* interface, for ip_output */
88	int		dir;		/* packet direction */
89#define	NG_IPFW_OUT	0
90#define	NG_IPFW_IN	1
91	int		flags;		/* flags, for ip_output() */
92};
93.Ed
94.Pp
95Packets received by a node from
96.Xr netgraph 4
97must be tagged with
98.Vt "struct ng_ipfw_tag"
99tag.
100Packets re-enter IP firewall processing at the next rule.
101If no tag is supplied, packets are discarded.
102.Sh CONTROL MESSAGES
103This node type supports only the generic control messages.
104.Sh SHUTDOWN
105This node shuts down upon receipt of a
106.Dv NGM_SHUTDOWN
107control message.
108Do not do this, since the new
109.Nm ipfw
110node can only be created by reloading the
111.Nm
112module.
113.Sh SEE ALSO
114.Xr ipfw 4 ,
115.Xr netgraph 4 ,
116.Xr ipfw 8 ,
117.Xr mbuf_tags 9
118.Sh HISTORY
119The
120.Nm ipfw
121node type was implemented in
122.Fx 6.0 .
123.Sh AUTHORS
124The
125.Nm ipfw
126node was written by
127.An "Gleb Smirnoff" Aq glebius@FreeBSD.org .
128