forked from Minki/linux
docs: networking: convert ppp_generic.txt to ReST
- add SPDX header; - adjust title markup; - mark code blocks and literals as such; - mark tables as such; - adjust identation, whitespaces and blank lines where needed; - add to networking/index.rst. Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Mauro Carvalho Chehab
David S. Miller
parent
32c01266c0
commit
71120802eb
@ -93,6 +93,7 @@ Contents:
|
||||
phonet
|
||||
pktgen
|
||||
plip
|
||||
ppp_generic
|
||||
|
||||
.. only:: subproject and html
|
||||
|
||||
|
||||
@ -1,8 +1,12 @@
|
||||
PPP Generic Driver and Channel Interface
|
||||
----------------------------------------
|
||||
.. SPDX-License-Identifier: GPL-2.0
|
||||
|
||||
Paul Mackerras
|
||||
========================================
|
||||
PPP Generic Driver and Channel Interface
|
||||
========================================
|
||||
|
||||
Paul Mackerras
|
||||
paulus@samba.org
|
||||
|
||||
7 Feb 2002
|
||||
|
||||
The generic PPP driver in linux-2.4 provides an implementation of the
|
||||
@ -19,7 +23,7 @@ functionality which is of use in any PPP implementation, including:
|
||||
* simple packet filtering
|
||||
|
||||
For sending and receiving PPP frames, the generic PPP driver calls on
|
||||
the services of PPP `channels'. A PPP channel encapsulates a
|
||||
the services of PPP ``channels``. A PPP channel encapsulates a
|
||||
mechanism for transporting PPP frames from one machine to another. A
|
||||
PPP channel implementation can be arbitrarily complex internally but
|
||||
has a very simple interface with the generic PPP code: it merely has
|
||||
@ -102,7 +106,7 @@ communications medium and prepare it to do PPP. For example, with an
|
||||
async tty, this can involve setting the tty speed and modes, issuing
|
||||
modem commands, and then going through some sort of dialog with the
|
||||
remote system to invoke PPP service there. We refer to this process
|
||||
as `discovery'. Then the user-level process tells the medium to
|
||||
as ``discovery``. Then the user-level process tells the medium to
|
||||
become a PPP channel and register itself with the generic PPP layer.
|
||||
The channel then has to report the channel number assigned to it back
|
||||
to the user-level process. From that point, the PPP negotiation code
|
||||
@ -111,8 +115,8 @@ negotiation, accessing the channel through the /dev/ppp interface.
|
||||
|
||||
At the interface to the PPP generic layer, PPP frames are stored in
|
||||
skbuff structures and start with the two-byte PPP protocol number.
|
||||
The frame does *not* include the 0xff `address' byte or the 0x03
|
||||
`control' byte that are optionally used in async PPP. Nor is there
|
||||
The frame does *not* include the 0xff ``address`` byte or the 0x03
|
||||
``control`` byte that are optionally used in async PPP. Nor is there
|
||||
any escaping of control characters, nor are there any FCS or framing
|
||||
characters included. That is all the responsibility of the channel
|
||||
code, if it is needed for the particular medium. That is, the skbuffs
|
||||
@ -121,16 +125,16 @@ protocol number and the data, and the skbuffs presented to ppp_input()
|
||||
must be in the same format.
|
||||
|
||||
The channel must provide an instance of a ppp_channel struct to
|
||||
represent the channel. The channel is free to use the `private' field
|
||||
however it wishes. The channel should initialize the `mtu' and
|
||||
`hdrlen' fields before calling ppp_register_channel() and not change
|
||||
them until after ppp_unregister_channel() returns. The `mtu' field
|
||||
represent the channel. The channel is free to use the ``private`` field
|
||||
however it wishes. The channel should initialize the ``mtu`` and
|
||||
``hdrlen`` fields before calling ppp_register_channel() and not change
|
||||
them until after ppp_unregister_channel() returns. The ``mtu`` field
|
||||
represents the maximum size of the data part of the PPP frames, that
|
||||
is, it does not include the 2-byte protocol number.
|
||||
|
||||
If the channel needs some headroom in the skbuffs presented to it for
|
||||
transmission (i.e., some space free in the skbuff data area before the
|
||||
start of the PPP frame), it should set the `hdrlen' field of the
|
||||
start of the PPP frame), it should set the ``hdrlen`` field of the
|
||||
ppp_channel struct to the amount of headroom required. The generic
|
||||
PPP layer will attempt to provide that much headroom but the channel
|
||||
should still check if there is sufficient headroom and copy the skbuff
|
||||
@ -322,6 +326,8 @@ an interface unit are:
|
||||
interface. The argument should be a pointer to an int containing
|
||||
the new flags value. The bits in the flags value that can be set
|
||||
are:
|
||||
|
||||
================ ========================================
|
||||
SC_COMP_TCP enable transmit TCP header compression
|
||||
SC_NO_TCP_CCID disable connection-id compression for
|
||||
TCP header compression
|
||||
@ -335,6 +341,7 @@ an interface unit are:
|
||||
SC_MP_SHORTSEQ expect short multilink sequence
|
||||
numbers on received multilink fragments
|
||||
SC_MP_XSHORTSEQ transmit short multilink sequence nos.
|
||||
================ ========================================
|
||||
|
||||
The values of these flags are defined in <linux/ppp-ioctl.h>. Note
|
||||
that the values of the SC_MULTILINK, SC_MP_SHORTSEQ and
|
||||
@ -345,17 +352,20 @@ an interface unit are:
|
||||
interface unit. The argument should point to an int where the ioctl
|
||||
will store the flags value. As well as the values listed above for
|
||||
PPPIOCSFLAGS, the following bits may be set in the returned value:
|
||||
|
||||
================ =========================================
|
||||
SC_COMP_RUN CCP compressor is running
|
||||
SC_DECOMP_RUN CCP decompressor is running
|
||||
SC_DC_ERROR CCP decompressor detected non-fatal error
|
||||
SC_DC_FERROR CCP decompressor detected fatal error
|
||||
================ =========================================
|
||||
|
||||
* PPPIOCSCOMPRESS sets the parameters for packet compression or
|
||||
decompression. The argument should point to a ppp_option_data
|
||||
structure (defined in <linux/ppp-ioctl.h>), which contains a
|
||||
pointer/length pair which should describe a block of memory
|
||||
containing a CCP option specifying a compression method and its
|
||||
parameters. The ppp_option_data struct also contains a `transmit'
|
||||
parameters. The ppp_option_data struct also contains a ``transmit``
|
||||
field. If this is 0, the ioctl will affect the receive path,
|
||||
otherwise the transmit path.
|
||||
|
||||
@ -377,7 +387,7 @@ an interface unit are:
|
||||
ppp_idle structure (defined in <linux/ppp_defs.h>). If the
|
||||
CONFIG_PPP_FILTER option is enabled, the set of packets which reset
|
||||
the transmit and receive idle timers is restricted to those which
|
||||
pass the `active' packet filter.
|
||||
pass the ``active`` packet filter.
|
||||
Two versions of this command exist, to deal with user space
|
||||
expecting times as either 32-bit or 64-bit time_t seconds.
|
||||
|
||||
@ -391,31 +401,33 @@ an interface unit are:
|
||||
|
||||
* PPPIOCSNPMODE sets the network-protocol mode for a given network
|
||||
protocol. The argument should point to an npioctl struct (defined
|
||||
in <linux/ppp-ioctl.h>). The `protocol' field gives the PPP protocol
|
||||
number for the protocol to be affected, and the `mode' field
|
||||
in <linux/ppp-ioctl.h>). The ``protocol`` field gives the PPP protocol
|
||||
number for the protocol to be affected, and the ``mode`` field
|
||||
specifies what to do with packets for that protocol:
|
||||
|
||||
============= ==============================================
|
||||
NPMODE_PASS normal operation, transmit and receive packets
|
||||
NPMODE_DROP silently drop packets for this protocol
|
||||
NPMODE_ERROR drop packets and return an error on transmit
|
||||
NPMODE_QUEUE queue up packets for transmit, drop received
|
||||
packets
|
||||
============= ==============================================
|
||||
|
||||
At present NPMODE_ERROR and NPMODE_QUEUE have the same effect as
|
||||
NPMODE_DROP.
|
||||
|
||||
* PPPIOCGNPMODE returns the network-protocol mode for a given
|
||||
protocol. The argument should point to an npioctl struct with the
|
||||
`protocol' field set to the PPP protocol number for the protocol of
|
||||
interest. On return the `mode' field will be set to the network-
|
||||
``protocol`` field set to the PPP protocol number for the protocol of
|
||||
interest. On return the ``mode`` field will be set to the network-
|
||||
protocol mode for that protocol.
|
||||
|
||||
* PPPIOCSPASS and PPPIOCSACTIVE set the `pass' and `active' packet
|
||||
* PPPIOCSPASS and PPPIOCSACTIVE set the ``pass`` and ``active`` packet
|
||||
filters. These ioctls are only available if the CONFIG_PPP_FILTER
|
||||
option is selected. The argument should point to a sock_fprog
|
||||
structure (defined in <linux/filter.h>) containing the compiled BPF
|
||||
instructions for the filter. Packets are dropped if they fail the
|
||||
`pass' filter; otherwise, if they fail the `active' filter they are
|
||||
``pass`` filter; otherwise, if they fail the ``active`` filter they are
|
||||
passed but they do not reset the transmit or receive idle timer.
|
||||
|
||||
* PPPIOCSMRRU enables or disables multilink processing for received
|
||||
Loading…
Reference in New Issue
Block a user