NAME¶
ng_iface
—
interface netgraph node type
SYNOPSIS¶
#include
<netgraph/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 accessible 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 protocol-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 can 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
(getifname
)
- Returns the name of the associated interface as a
NUL
-terminated ASCII string. Normally
this is the same as the name of the node.
NGM_IFACE_GET_IFINDEX
(getifindex
)
- Returns the global index of the associated interface as a 32 bit
integer.
NGM_IFACE_POINT2POINT
(point2point
)
- Set the interface to point-to-point mode. The interface must not currently
be up.
NGM_IFACE_BROADCAST
(broadcast
)
- Set the interface to broadcast mode. The interface must not currently be
up.
NGM_CISCO_GET_IPADDR
(getipaddr
)
- 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.
ALTQ Support¶
The
ng_iface
interface supports ALTQ
bandwidth management feature. However,
ng_iface
is a special case, since it is not
a physical interface with limited bandwidth. One should not turn ALTQ on
ng_iface
if the latter corresponds to some
tunneled connection, e.g. PPPoE or PPTP. In this case, ALTQ should be
configured on the interface that is used to transmit the encapsulated packets.
In case when your graph ends up with some kind of serial line, either
synchronous or modem, the
ng_iface
is the
right place to turn ALTQ on.
SEE ALSO¶
altq(4),
bpf(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⟩