ng_sppp(4)

NAME

ng_sppp - sppp netgraph node type

SYNOPSIS

#include <netgraph/ng_sppp.h>

DESCRIPTION

An sppp node is a netgraph(4) interface to the original

sppp(4) network
module for synchronous lines. Currently, sppp(4) supports

PPP and Cisco
HDLC protocols. An sppp node could be considered as an al

ternative kernel mode PPP implementation to net/mpd port + ng_ppp(4), and

as an alternative to ng_cisco(4) node. While having less features than

net/mpd +
ng_ppp(4), it is significantly easier to use in the majority

of simple
configurations, and allows the administrator to not install

the net/mpd
port. With sppp you do not need any other nodes, not even

an ng_iface(4)
node. When an sppp node is created, a new interface appears

which is
accessible via ifconfig(8). Network interfaces correspond

ing to sppp
nodes are named sppp0, sppp1, etc. When a node is shut

down, the corresponding interface is removed, and the interface name be

comes available
for reuse by future sppp 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 re

mains unnamed.
The sppp node allows drivers written to the old sppp(4) in

terface to be
rewritten using the newer more powerful netgraph(4) inter

face, and still
behave in a compatible manner without supporting both net

work modules.

An sppp node has a single hook named downstream. Usually it

is connected
directly to a device driver hook.

The sppp nodes support the Berkeley Packet Filter, bpf(4).

HOOKS

This node type supports the following hooks:

downstream The connection to the synchronous line.

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.

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
sppp nodes.

Unlike most other node types and like ng_iface(4) does, an

sppp node does
not go away when all hooks have been disconnected; rather,

an explicit
NGM_SHUTDOWN control message is required.

EXAMPLES

For example, if you have the cx(4) device, you could run PPP

over it with
just one command:

ngctl mkpeer cx0: sppp rawdata downstream

Now you have the sppp0 interface (if this was the first sppp

node) which
can be accessed via ifconfig(8) as a normal network inter

face, or via
spppcontrol(8) as an sppp(4) interface.

SEE ALSO

bpf(4), cx(4), netgraph(4), ng_cisco(4), ng_iface(4),

ng_ppp(4), sppp(4),
ifconfig(8), ngctl(8), spppcontrol(8)

For complex networking topologies you may want to look at

net/mpd port.

HISTORY

The sppp node type was implemented for FreeBSD 5.0. It was

included to
the system since FreeBSD 5.3.

AUTHORS

Copyright (C) 2003-2004 Roman Kurakin <rik@cronyx.ru>.

BSD February 3, 2005

BSD