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NG_IFACE(4)		     Kernel Interfaces Manual		     NG_IFACE(4)

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 inter-
     face as packets received into the corresponding protocol stack.   The  cur-
     rently 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 broad-
     cast 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 associated interface as a NUL-terminated ASCII
	  string.  Normally this is the same as the name of the node.

     NGM_IFACE_GET_IFINDEX
	  Returns the global index of the associated interface as a 32 bit inte-
	  ger.

     NGM_IFACE_POINT2POINT
	  Set the interface to point-to-point mode.  The interface must not cur-
	  rently be up.

     NGM_IFACE_BROADCAST
	  Set the interface to broadcast mode.	The interface must not currently
	  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.

ALTQ Support
     The  ng_iface  interface  supports ALTQ bandwidth management feature.  How-
     ever, 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 cor-
     responds 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 en-
     capsulated packets.  In case when your graph ends up with some kind of ser-
     ial  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>

FreeBSD 9.0			October 28, 2005		     NG_IFACE(4)
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