ng_sppp —
sppp
netgraph node type
#include
<netgraph/ng_sppp.h>
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
alternative 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 corresponding to
sppp nodes are named
sppp0,
sppp1, etc. When a node
is shut down, the corresponding interface is removed, and the interface name
becomes 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 remains unnamed. The
sppp node allows
drivers written to the old
sppp(4) interface to
be rewritten using the newer more powerful
netgraph(4) interface, and still behave in a
compatible manner without supporting both network 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).
This node type supports the following hooks:
- downstream
- The connection to the synchronous line.
This node type supports the generic control messages, plus the following:
-
NGM_SPPP_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.
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.
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 interface, or via
spppcontrol(8) as an
sppp(4) interface.
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.
The
sppp node type was implemented for
FreeBSD 5.0. It was included to the system since
FreeBSD 5.3.
Copyright (C) 2003-2004
Roman Kurakin
<
[email protected]>