FreeBSD Man Pages

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 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 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 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_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 ALSO

     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 5.4		       January 19, 1999 		   FreeBSD 5.4

SPONSORED LINKS