bionic (4) ng_ipfw.4freebsd.gz

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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
     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>.