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.\" Copyright (c) 1996-2000 Whistle Communications, Inc.
.\" All rights reserved.
.\"
.\" Subject to the following obligations and disclaimer of warranty, use and
.\" redistribution of this software, in source or object code forms, with or
.\" without modifications are expressly permitted by Whistle Communications;
.\" provided, however, that:
.\" 1. Any and all reproductions of the source or object code must include the
.\" copyright notice above and the following disclaimer of warranties; and
.\" 2. No rights are granted, in any manner or form, to use Whistle
.\" Communications, Inc. trademarks, including the mark "WHISTLE
.\" COMMUNICATIONS" on advertising, endorsements, or otherwise except as
.\" such appears in the above copyright notice or in the software.
.\"
.\" THIS SOFTWARE IS BEING PROVIDED BY WHISTLE COMMUNICATIONS "AS IS", AND
.\" TO THE MAXIMUM EXTENT PERMITTED BY LAW, WHISTLE COMMUNICATIONS MAKES NO
.\" REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, REGARDING THIS SOFTWARE,
.\" INCLUDING WITHOUT LIMITATION, ANY AND ALL IMPLIED WARRANTIES OF
.\" MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT.
.\" WHISTLE COMMUNICATIONS DOES NOT WARRANT, GUARANTEE, OR MAKE ANY
.\" REPRESENTATIONS REGARDING THE USE OF, OR THE RESULTS OF THE USE OF THIS
.\" SOFTWARE IN TERMS OF ITS CORRECTNESS, ACCURACY, RELIABILITY OR OTHERWISE.
.\" IN NO EVENT SHALL WHISTLE COMMUNICATIONS BE LIABLE FOR ANY DAMAGES
.\" RESULTING FROM OR ARISING OUT OF ANY USE OF THIS SOFTWARE, INCLUDING
.\" WITHOUT LIMITATION, ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
.\" PUNITIVE, OR CONSEQUENTIAL DAMAGES, PROCUREMENT OF SUBSTITUTE GOODS OR
.\" SERVICES, LOSS OF USE, DATA OR PROFITS, HOWEVER CAUSED AND UNDER ANY
.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
.\" THIS SOFTWARE, EVEN IF WHISTLE COMMUNICATIONS IS ADVISED OF THE POSSIBILITY
.\" OF SUCH DAMAGE.
.\"
.\" Author: Archie Cobbs <archie@FreeBSD.org>
.\"
.\" $Whistle: ng_mppc.8,v 1.1 1999/12/08 20:20:39 archie Exp $
.\" $FreeBSD$
.\"
.Dd June 7, 2016
.Dt NG_MPPC 4
.Os
.Sh NAME
.Nm ng_mppc
.Nd Microsoft MPPC/MPPE compression and encryption netgraph node type
.Sh SYNOPSIS
.In sys/types.h
.In netgraph/ng_mppc.h
.Sh DESCRIPTION
The
.Nm mppc
node type implements the Microsoft Point-to-Point Compression (MPPC)
and Microsoft Point-to-Point Encryption (MPPE) sub-protocols of
the PPP protocol.
These protocols are often used in conjunction with the Point-to-Point
Tunneling Protocol (PPTP).
.Pp
The node has two hooks,
.Dv "comp"
for compression and
.Dv "decomp"
for decompression.
Typically one or both of these hooks would be connected to the
.Xr ng_ppp 4
node type hook of the same name.
Each direction of traffic flow is independent of the other.
.Sh HOOKS
This node type supports the following hooks:
.Bl -tag -width ".Va decomp"
.It Va comp
Connection to
.Xr ng_ppp 4
.Dv "comp"
hook.
Incoming frames are compressed and/or encrypted, and sent
back out the same hook.
.It Va decomp
Connection to
.Xr ng_ppp 4
.Dv "decomp"
hook.
Incoming frames are decompressed and/or decrypted, and sent
back out the same hook.
.El
.Sh CONTROL MESSAGES
This node type supports the generic control messages, plus the following:
.Bl -tag -width foo
.It Dv NGM_MPPC_CONFIG_COMP
This command resets and configures the node for a session in the
outgoing traffic direction (i.e., for compression and/or encryption).
This command takes a
.Dv "struct ng_mppc_config"
as an argument:
.Bd -literal -offset 0n
/* Length of MPPE key */
#define MPPE_KEY_LEN 16
/* MPPC/MPPE PPP negotiation bits */
#define MPPC_BIT 0x00000001 /* mppc compression bits */
#define MPPE_40 0x00000020 /* use 40 bit key */
#define MPPE_56 0x00000080 /* use 56 bit key */
#define MPPE_128 0x00000040 /* use 128 bit key */
#define MPPE_BITS 0x000000e0 /* mppe encryption bits */
#define MPPE_STATELESS 0x01000000 /* use stateless mode */
#define MPPC_VALID_BITS 0x010000e1 /* possibly valid bits */
/* Configuration for a session */
struct ng_mppc_config {
u_char enable; /* enable */
uint32_t bits; /* config bits */
u_char startkey[MPPE_KEY_LEN]; /* start key */
};
.Ed
The
.Dv enabled
field enables traffic flow through the node.
The
.Dv bits
field contains the bits as negotiated by the Compression Control Protocol
(CCP) in PPP.
The
.Dv startkey
is only necessary if MPPE was negotiated, and must be equal to the
session start key as defined for MPPE.
This key is based on the MS-CHAP credentials used at link authentication time.
.It Dv NGM_MPPC_CONFIG_DECOMP
This command resets and configures the node for a session in the
incoming traffic direction (i.e., for decompression and/or decryption).
This command takes a
.Dv "struct ng_mppc_config"
as an argument.
.It Dv NGM_MPPC_RESETREQ
This message contains no arguments, and is bi-directional.
If an error is detected during decompression, this message is sent by the
node to the originator of the
.Dv NGM_MPPC_CONFIG_DECOMP
message that initiated the session.
The receiver should respond by sending a PPP CCP Reset-Request to the peer.
.Pp
This message may also be received by this node type when a CCP Reset-Request
is received by the local PPP entity.
The node will respond by flushing its outgoing compression and encryption
state so the remote side can resynchronize.
.El
.Sh SHUTDOWN
This node shuts down upon receipt of a
.Dv NGM_SHUTDOWN
control message, or when both hooks have been disconnected.
.Sh COMPILATION
The kernel options
.Dv NETGRAPH_MPPC_COMPRESSION
and
.Dv NETGRAPH_MPPC_ENCRYPTION
are supplied to selectively compile in either or both capabilities.
At least one of these must be defined, or else this node type is useless.
.Pp
.Sh SEE ALSO
.Xr netgraph 4 ,
.Xr ng_ppp 4 ,
.Xr ngctl 8
.Rs
.%A G. Pall
.%T "Microsoft Point-To-Point Compression (MPPC) Protocol"
.%O RFC 2118
.Re
.Rs
.%A G. S. Pall
.%A G. Zorn
.%T "Microsoft Point-To-Point Encryption (MPPE) Protocol"
.%O draft-ietf-pppext-mppe-04.txt
.Re
.Rs
.%A K. Hamzeh
.%A G. Pall
.%A W. Verthein
.%A J. Taarud
.%A W. Little
.%A G. Zorn
.%T "Point-to-Point Tunneling Protocol (PPTP)"
.%O RFC 2637
.Re
.Sh AUTHORS
.An Archie Cobbs Aq Mt archie@FreeBSD.org
.Sh BUGS
In PPP, encryption should be handled by the Encryption Control Protocol (ECP)
rather than CCP.
However, Microsoft combined both compression and encryption into their
``compression'' algorithm, which is confusing.
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