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diff --git a/share/man/man4/ng_async.4 b/share/man/man4/ng_async.4 new file mode 100644 index 0000000..324fa41 --- /dev/null +++ b/share/man/man4/ng_async.4 @@ -0,0 +1,172 @@ +.\" Copyright (c) 1996-1999 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> +.\" +.\" $FreeBSD$ +.\" $Whistle: ng_async.8,v 1.6 1999/01/25 23:46:25 archie Exp $ +.\" +.Dd November 13, 2012 +.Dt NG_ASYNC 4 +.Os +.Sh NAME +.Nm ng_async +.Nd asynchronous framing netgraph node type +.Sh SYNOPSIS +.In sys/types.h +.In netgraph/ng_async.h +.Sh DESCRIPTION +The +.Nm async +node type performs conversion between synchronous frames and +asynchronous frames, as defined for the PPP protocol in RFC 1662. +Asynchronous framing uses flag bytes and octet-stuffing +to simulate a frame oriented connection over an octet-oriented +asynchronous serial line. +.Pp +The node transmits and receives asynchronous data on the +.Dv async +hook. +Mbuf boundaries of incoming data are ignored. +Once a complete packet has been received, it is decoded and +stripped of all framing bytes, and transmitted out the +.Dv sync +hook as a single frame. +.Pp +Synchronous frames are transmitted and received on the +.Dv sync +hook. +Packets received on this hook are encoded as asynchronous frames +and sent out on +.Dv async . +Received packets should start with the address and control fields, +or the PPP protocol field if address and control field compression +is employed, and contain no checksum field. +If the first four bytes are +.Dv "0xff 0x03 0xc0 0x21" +(an LCP protocol frame) then complete control character escaping +is enabled for that frame (in PPP, LCP packets are always sent with +no address and control field compression and all control characters +escaped). +.Pp +This node supports +.Dq flag sharing +for packets transmitted on +.Dv async . +This is an optimization where the trailing flag byte +of one frame is shared with the opening flag byte of the next. +Flag sharing between frames is disabled after one second of transmit +idle time. +.Sh HOOKS +This node type supports the following hooks: +.Bl -tag -width ".Va async" +.It Va async +Asynchronous connection. +Typically this hook would be connected to a +.Xr ng_tty 4 +node, which handles transmission of serial data over a tty device. +.It Va sync +Synchronous connection. +This hook sends and receives synchronous frames. +For PPP, these frames should contain address, control, and protocol fields, +but no checksum field. +Typically this hook would be connected to an individual link hook of a +.Xr ng_ppp 4 +type node. +.El +.Sh CONTROL MESSAGES +This node type supports the generic control messages, plus the following: +.Bl -tag -width foo +.It Dv NGM_ASYNC_CMD_SET_CONFIG Pq Ic setconfig +Sets the node configuration, which is described by a +.Dv "struct ng_async_cfg" : +.Bd -literal -offset 4n +struct ng_async_cfg { + u_char enabled; /* Turn encoding on/off */ + uint16_t amru; /* Max receive async frame length */ + uint16_t smru; /* Max receive sync frame length */ + uint32_t accm; /* ACCM encoding */ +}; +.Ed +The +.Dv enabled +field enables or disables all encoding/decoding functions (default disabled). +When disabled, the node operates in simple +.Dq pass through +mode. +The +.Dv amru +and +.Dv smru +fields are the asynchronous and synchronous MRU (maximum receive unit) values, +respectively. +These both default to 1600; note that the async MRU +applies to the incoming frame length after asynchronous decoding. +The +.Dv accm +field is the asynchronous character control map, which controls the escaping +of characters 0x00 thorough 0x1f (default 0xffffffff). +.It Dv NGM_ASYNC_CMD_GET_CONFIG Pq Ic getconfig +This command returns the current configuration structure. +.It Dv NGM_ASYNC_CMD_GET_STATS Pq Ic getstats +This command returns a +.Dv "struct ng_async_stat" +containing node statistics for packet, octet, and error counts. +.It Dv NGM_ASYNC_CMD_CLR_STATS Pq Ic clrstats +Clears the node statistics. +.El +.Sh SHUTDOWN +This node shuts down upon receipt of a +.Dv NGM_SHUTDOWN +control message, or when all hooks have been disconnected. +.Sh SEE ALSO +.Xr netgraph 4 , +.Xr ng_ppp 4 , +.Xr ng_tty 4 , +.Xr ngctl 8 +.Rs +.%A W. Simpson +.%T "PPP in HDLC-link Framing" +.%O RFC 1662 +.Re +.Rs +.%A W. Simpson +.%T "The Point-to-Point Protocol (PPP)" +.%O RFC 1661 +.Re +.Sh HISTORY +The +.Nm +node type was implemented in +.Fx 4.0 . +.Sh AUTHORS +.An Archie Cobbs Aq archie@FreeBSD.org |
