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) 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 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 */
uint32_t rule_id; /* matching rule id */
uint32_t chain_id; /* ruleset id */
struct ifnet *ifp; /* interface, for ip_output */
int dir; /* packet direction */
#define NG_IPFW_OUT 0
#define NG_IPFW_IN 1
};
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⟩.