1.\" 2.\" Author: Alexander Motin <mav@alkar.net> 3.\" 4.\" Copyright (c) 2006, Alexander Motin <mav@alkar.net> 5.\" All rights reserved. 6.\" 7.\" Redistribution and use in source and binary forms, with or without 8.\" modification, are permitted provided that the following conditions 9.\" are met: 10.\" 1. Redistributions of source code must retain the above copyright 11.\" notice unmodified, this list of conditions, and the following 12.\" disclaimer. 13.\" 2. Redistributions in binary form must reproduce the above copyright 14.\" notice, this list of conditions and the following disclaimer in the 15.\" documentation and/or other materials provided with the distribution. 16.\" 17.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 18.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 21.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27.\" SUCH DAMAGE. 28.\" 29.Dd December 23, 2006 30.Dt NG_DEFLATE 4 31.Os 32.Sh NAME 33.Nm ng_deflate 34.Nd Deflate PPP compression (RFC 1979) netgraph node type 35.Sh SYNOPSIS 36.In sys/types.h 37.In netgraph/ng_deflate.h 38.Sh DESCRIPTION 39The 40.Nm deflate 41node type implements the Deflate sub-protocols of the Compression Control 42Protocol (CCP). 43.Pp 44The node has two hooks, 45.Va comp 46for compression and 47.Va decomp 48for decompression. 49Only one of them can be connected at the same time, specifying node's 50operation mode. 51Typically that hooks would be connected to the 52.Xr ng_ppp 4 53node type hook of the same name. 54Corresponding 55.Xr ng_ppp 4 56node hook must be switched to 57.Dv NG_PPP_DECOMPRESS_FULL 58mode to permit sending uncompressed frames. 59.Sh HOOKS 60This node type supports the following hooks: 61.Pp 62.Bl -tag -compact -width ".Va decomp" 63.It Va comp 64Connection to 65.Xr ng_ppp 4 66.Va comp 67hook. 68Incoming frames are compressed (if possible) and sent back out the same hook. 69.It Va decomp 70Connection to 71.Xr ng_ppp 4 72.Va decomp 73hook. 74Incoming frames are decompressed (if they are compressed), and sent 75back out the same hook. 76.El 77.Pp 78Only one hook can be connected at the same time, specifying node's 79operation mode. 80.Sh CONTROL MESSAGES 81This node type supports the generic control messages, plus the following: 82.Bl -tag -width foo 83.It Dv NGM_DEFLATE_CONFIG Pq Ic config 84This command resets and configures the node for a session 85(i.e., for compression or decompression). 86This command takes a 87.Vt "struct ng_deflate_config" 88as an argument: 89.Bd -literal -offset 0n 90struct ng_deflate_config { 91 u_char enable; /* node enabled */ 92 u_char windowBits; /* log2(Window size) */ 93}; 94.Ed 95The 96.Fa enabled 97field enables traffic flow through the node. 98The 99.Fa windowBits 100specify compression windows size as negotiated by the 101Compression Control Protocol (CCP) in PPP. 102.It Dv NGM_DEFLATE_RESETREQ Pq Ic resetreq 103This message contains no arguments, and is bi-directional. 104If an error is detected during decompression, this message is sent by the 105node to the originator of the 106.Dv NGM_DEFLATE_CONFIG 107message that initiated the session. 108The receiver should respond by sending a PPP CCP Reset-Request to the peer. 109.Pp 110This message may also be received by this node type when a CCP Reset-Request 111or Reset-Ack is received by the local PPP entity. 112The node will respond by flushing its compression state so the sides 113can resynchronize. 114.It Dv NGM_DEFLATE_GET_STATS Pq Ic getstats 115This control message obtains statistics for a given hook. 116The statistics are returned in 117.Vt "struct ng_deflate_stats" : 118.Bd -literal 119struct ng_deflate_stats { 120 uint64_t FramesPlain; 121 uint64_t FramesComp; 122 uint64_t FramesUncomp; 123 uint64_t InOctets; 124 uint64_t OutOctets; 125 uint64_t Errors; 126}; 127.Ed 128.It Dv NGM_DEFLATE_CLR_STATS Pq Ic clrstats 129This control message clears statistics for a given hook. 130.It Dv NGM_DEFLATE_GETCLR_STATS Pq Ic getclrstats 131This control message obtains and clears statistics for a given hook. 132.El 133.Sh SHUTDOWN 134This node shuts down upon receipt of a 135.Dv NGM_SHUTDOWN 136control message, or when hook have been disconnected. 137.Sh SEE ALSO 138.Xr netgraph 4 , 139.Xr ng_ppp 4 , 140.Xr ngctl 8 141.Rs 142.%A J. Woods 143.%T "PPP Deflate Protocol" 144.%O RFC 1979 145.Re 146.Rs 147.%A W. Simpson 148.%T "The Point-to-Point Protocol (PPP)" 149.%O RFC 1661 150.Re 151.Sh AUTHORS 152.An Alexander Motin Aq Mt mav@alkar.net 153.Sh BUGS 154Due to nature of netgraph PPP implementation there are possible race conditions 155between data packet and ResetAck CCP packet in case of packet loss. 156As result, 157packet loss can produce bigger performance degradation than supposed by protocol. 158