| NG_IPFW(4) | Device Drivers Manual | NG_IPFW(4) |
ng_ipfw —
interface between netgraph and IP firewall
#include
<netinet/ip_var.h>
#include
<netgraph/ng_ipfw.h>
The ipfw node implements interface between
ipfw(4) and netgraph(4) subsystems.
The ipfw node supports an arbitrary number
of hooks, which must be named using only numeric characters.
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.
This node type supports only the generic control messages.
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.
The ipfw node type was implemented in
FreeBSD 6.0.
The ipfw node was written by
Gleb Smirnoff
<glebius@FreeBSD.org>.
| March 2, 2010 | Debian |