.\" Copyright (C) 2003-2004 Cronyx Engineering.
.\" Copyright (C) 2003-2004 Roman Kurakin <rik@cronyx.ru>
.\"
.\" This software is distributed with NO WARRANTIES, not even the implied
.\" warranties for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
.\"
.\" Authors grant any other persons or organisations a permission to use,
.\" modify and redistribute this software in source and binary forms,
.\" as long as this message is kept with the software, all derivative
.\" works or modified versions.
.\"
.\" Cronyx Id: ng_sppp.4,v 1.1.2.3 2004/03/30 14:28:34 rik Exp $
.\"
.Dd October 22, 2021
.Dt NG_SPPP 4
.Os
.Sh NAME
.Nm ng_sppp
.Nd sppp netgraph node type
.Sh SYNOPSIS
.In netgraph/ng_sppp.h
.Sh DEPRECATION NOTICE
The
.Nm
module is not present in
.Fx 14.0
and later.
.Sh DESCRIPTION
An
.Nm sppp
node is a
.Xr netgraph 4
interface to the original
.Xr sppp 4
network module for synchronous lines.
Currently,
.Xr sppp 4
supports PPP and Cisco HDLC protocols.
An
.Nm sppp
node could be considered as an alternative kernel mode PPP
implementation to
.Pa net/mpd
port +
.Xr ng_ppp 4 ,
and as an alternative to
.Xr ng_cisco 4
node.
While having less features than
.Pa net/mpd
+
.Xr ng_ppp 4 ,
it is significantly easier to use in the majority of simple configurations,
and allows the administrator to not install the
.Pa net/mpd
port.
With
.Nm sppp
you do not need any other nodes, not even an
.Xr ng_iface 4
node.
When an
.Nm sppp
node is created, a new interface appears which is accessible via
.Xr ifconfig 8 .
Network interfaces corresponding to
.Nm sppp
nodes are named
.Li sppp0 , sppp1 ,
etc.
When a node is shut down, the corresponding interface is removed,
and the interface name becomes available for reuse by future
.Nm 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 remains unnamed.
The
.Nm sppp
node allows drivers written to the old
.Xr sppp 4
interface to be rewritten using the
newer more powerful
.Xr netgraph 4
interface, and still behave in a compatible manner without supporting both
network modules.
.Pp
An
.Nm sppp
node has a single hook named
.Va downstream .
Usually it is connected directly to
a device driver hook.
.Pp
The
.Nm sppp
nodes support the Berkeley Packet Filter,
.Xr bpf 4 .
.Sh HOOKS
This node type supports the following hooks:
.Bl -tag -width ".Va downstream"
.It Va downstream
The connection to the synchronous line.
.El
.Sh CONTROL MESSAGES
This node type supports the generic control messages, plus the following:
.Bl -tag -width foo
.It Dv NGM_SPPP_GET_IFNAME Pq Ic getifname
Returns the name of the associated interface as a
.Dv NUL Ns -terminated
.Tn ASCII
string.
Normally this is the same as the name of the node.
.El
.Sh SHUTDOWN
This node shuts down upon receipt of a
.Dv NGM_SHUTDOWN
control message.
The associated interface is removed and becomes available
for use by future
.Nm sppp
nodes.
.Pp
Unlike most other node types and like
.Xr ng_iface 4
does, an
.Nm sppp
node does
.Em not
go away when all hooks have been disconnected; rather, an explicit
.Dv NGM_SHUTDOWN
control message is required.
.Sh EXAMPLES
For example, if you have the
.Xr cx 4
device, you could run PPP over it with just one command:
.Pp
.Dl "ngctl mkpeer cx0: sppp rawdata downstream"
.Pp
Now you have the
.Li sppp0
interface (if this was the first
.Nm sppp
node) which can be
accessed via
.Xr ifconfig 8
as a normal network interface,
or via
.Xr spppcontrol 8
as an
.Xr sppp 4
interface.
.Sh SEE ALSO
.Xr bpf 4 ,
.Xr cx 4 ,
.Xr netgraph 4 ,
.Xr ng_cisco 4 ,
.Xr ng_iface 4 ,
.Xr ng_ppp 4 ,
.Xr sppp 4 ,
.Xr ifconfig 8 ,
.Xr ngctl 8 ,
.Xr spppcontrol 8
.Pp
For complex networking topologies you may want to look at
.Pa net/mpd
port.
.Sh HISTORY
The
.Nm sppp
node type was implemented for
.Fx 5.0 .
It was included to the system since
.Fx 5.3 .
.Sh AUTHORS
Copyright (C) 2003-2004
.An Roman Kurakin Aq Mt rik@cronyx.ru