NG_IFACE(4) BSD Kernel Interfaces Manual NG_IFACE(4)NAMEng_iface — interface netgraph node type
SYNOPSIS
#include <netgraph/iface/ng_iface.h>
DESCRIPTION
An iface node is both a netgraph node and a system networking interface.
When an iface node is created, a new interface appears which is accessi‐
ble via ifconfig(8). Iface node interfaces are named ng0, ng1, etc.
When a node is shutdown, the corresponding interface is removed and the
interface name becomes available for reuse by future iface nodes; new
nodes always take the first unused interface. The node itself is
assigned the same name as its interface, unless the name already exists,
in which case the node remains unnamed.
An iface node has a single hook corresponding to each supported protocol.
Packets transmitted via the interface flow out the corresponding proto‐
col-specific hook. Similarly, packets received on a hook appear on the
interface as packets received into the corresponding protocol stack. The
currently supported protocols are IP, IPv6, AppleTalk, IPX, ATM, NATM,
and NS.
An iface node be configured as a point-to-point interface or a broadcast
interface. The configuration can only be changed when the interface is
down. The default mode is point-to-point.
Iface nodes support the Berkeley Packet Filter (BPF).
HOOKS
This node type supports the following hooks:
inet Transmission and reception of IP packets.
inet6 Transmission and reception of IPv6 packets.
atalk Transmission and reception of AppleTalk packets.
ipx Transmission and reception of IPX packets.
atm Transmission and reception of ATM packets.
natm Transmission and reception of NATM packets.
ns Transmission and reception of NS packets.
CONTROL MESSAGES
This node type supports the generic control messages, plus the following:
NGM_IFACE_GET_IFNAME
Returns the name of the interface corresponding to this node in a
struct ng_iface_ifname:
struct ng_iface_ifname {
char ngif_name[NG_IFACE_IFACE_NAME_MAX + 1];
};
NGM_IFACE_POINT2POINT
Set the interface to point-to-point mode. The interface must not
currently be up.
NGM_IFACE_BROADCAST
Set the interface to broadcast mode. The interface must not cur‐
rently be up.
NGM_CISCO_GET_IPADDR
This message is defined by the ng_cisco(4) node type; see
ng_cisco(4) for a description.
SHUTDOWN
This node shuts down upon receipt of a NGM_SHUTDOWN control message. The
associated interface is removed and becomes available for use by future
iface nodes.
Unlike most other node types, an iface node does not go away when all
hooks have been disconnected; rather, and explicit NGM_SHUTDOWN control
message is required.
SEE ALSObpf(4), netgraph(4), ng_cisco(4), ifconfig(8), ngctl(8)HISTORY
The iface node type was implemented in FreeBSD 4.0.
AUTHORS
Archie Cobbs ⟨archie@FreeBSD.org⟩
BSD January 19, 1999 BSD
