Проект OpenNet: MAN ng_ipfw (4) Специальные файлы /dev/* (FreeBSD и Linux)

Интерактивная система просмотра системных руководств (man-ов)

ng_ipfw (4)

>> ng_ipfw (4) ( FreeBSD man: Специальные файлы /dev/* )

BSD mandoc

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 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 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 Vt 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 Vt 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 module.