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No rights are granted, in any manner or form, to use Whistle 11.\" Communications, Inc. trademarks, including the mark "WHISTLE 12.\" COMMUNICATIONS" on advertising, endorsements, or otherwise except as 13.\" such appears in the above copyright notice or in the software. 14.\" 15.\" THIS SOFTWARE IS BEING PROVIDED BY WHISTLE COMMUNICATIONS "AS IS", AND 16.\" TO THE MAXIMUM EXTENT PERMITTED BY LAW, WHISTLE COMMUNICATIONS MAKES NO 17.\" REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, REGARDING THIS SOFTWARE, 18.\" INCLUDING WITHOUT LIMITATION, ANY AND ALL IMPLIED WARRANTIES OF 19.\" MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT. 20.\" WHISTLE COMMUNICATIONS DOES NOT WARRANT, GUARANTEE, OR MAKE ANY 21.\" REPRESENTATIONS REGARDING THE USE OF, OR THE RESULTS OF THE USE OF THIS 22.\" SOFTWARE IN TERMS OF ITS CORRECTNESS, ACCURACY, RELIABILITY OR OTHERWISE. 23.\" IN NO EVENT SHALL WHISTLE COMMUNICATIONS BE LIABLE FOR ANY DAMAGES 24.\" RESULTING FROM OR ARISING OUT OF ANY USE OF THIS SOFTWARE, INCLUDING 25.\" WITHOUT LIMITATION, ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, 26.\" PUNITIVE, OR CONSEQUENTIAL DAMAGES, PROCUREMENT OF SUBSTITUTE GOODS OR 27.\" SERVICES, LOSS OF USE, DATA OR PROFITS, HOWEVER CAUSED AND UNDER ANY 28.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 29.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 30.\" THIS SOFTWARE, EVEN IF WHISTLE COMMUNICATIONS IS ADVISED OF THE POSSIBILITY 31.\" OF SUCH DAMAGE. 32.\" 33.\" Author: Archie Cobbs <archie@FreeBSD.org> 34.\" 35.\" $FreeBSD: src/share/man/man4/ng_pptpgre.4,v 1.16.2.2 2002/03/19 18:24:07 schweikh Exp $ 36.\" $Whistle: ng_pptpgre.8,v 1.2 1999/12/08 00:20:53 archie Exp $ 37.\" 38.Dd December 7, 2001 39.Dt NG_PPTPGRE 4 40.Os 41.Sh NAME 42.Nm ng_pptpgre 43.Nd PPTP GRE protocol netgraph node type 44.Sh SYNOPSIS 45.In netgraph/pptpgre/ng_pptpgre.h 46.Sh DESCRIPTION 47The 48.Nm pptpgre 49node type performs Generic Routing Encapsulation (GRE) over IP 50for the PPTP protocol as specified by RFC 2637. 51This involves packet 52encapsulation, sequencing, acknowledgement, and an adaptive timeout 53sliding window mechanism. 54This node type does not handle any of 55the TCP control protocol or call negotiation defined by PPTP. 56.Pp 57This node type expects to receive complete IP packets, 58including the IP header, on the 59.Dq Li lower 60hook, but it transmits outgoing frames without any IP header. 61The typical use for this node type would be to connect the 62.Dq Li upper 63hook to one of the link hooks of a 64.Xr ng_ppp 4 65node, and the 66.Dq Li lower 67hook to the 68.Dq Li "inet/raw/gre" 69hook of a 70.Xr ng_ksocket 4 71node. 72.Sh HOOKS 73This node type supports the following hooks: 74.Pp 75.Bl -tag -compact -width ".Li upper" 76.It Li upper 77Connection to the upper protocol layers 78.It Li lower 79Connection to the lower protocol layers 80.El 81.Sh CONTROL MESSAGES 82This node type supports the generic control messages, plus the following: 83.Bl -tag -width indent 84.It Dv NGM_PPTPGRE_SET_CONFIG 85This command resets and configures the node for a session. 86This command takes a 87.Vt "struct ng_pptpgre_conf" 88as an argument: 89.Bd -literal 90/* Configuration for a session */ 91struct ng_pptpgre_conf { 92 u_char enabled; /* enables traffic flow */ 93 u_char enableDelayedAck; /* enables delayed acks */ 94 u_char enableAlwaysAck; /* always send ack with data */ 95 u_int16_t cid; /* my call id */ 96 u_int16_t peerCid; /* peer call id */ 97 u_int16_t recvWin; /* peer recv window size */ 98 u_int16_t peerPpd; /* peer packet processing delay 99 (in 1/10 of a second) */ 100}; 101.Ed 102.Pp 103The 104.Va enabled 105field enables traffic flow through the node. 106The 107.Va enableDelayedAck 108field enables delayed acknowledgement (maximum 250 milliseconds), which 109is a useful optimization and should generally be turned on. 110.Va enableAlwaysAck 111field enables sending acknowledgements with every data packet, which 112is probably helpful as well. 113The remaining fields are as supplied by the PPTP virtual call setup process. 114.It Dv NGM_PPTPGRE_GET_CONFIG 115Returns the current configuration as a 116.Vt "struct ng_pptpgre_conf" . 117.It Dv NGM_PPTPGRE_GET_STATS 118This command returns a 119.Vt "struct ng_pptpgre_stats" 120containing various node statistics. 121.It Dv NGM_PPTPGRE_CLR_STATS 122This command resets the node statistics. 123.It Dv NGM_PPTPGRE_GETCLR_STATS 124This command atomically gets and resets the node statistics, returning a 125.Vt "struct ng_pptpgre_stats" . 126.El 127.Sh SHUTDOWN 128This node shuts down upon receipt of a 129.Dv NGM_SHUTDOWN 130control message, or when both hooks have been disconnected. 131.Sh SEE ALSO 132.Xr netgraph 4 , 133.Xr ng_ksocket 4 , 134.Xr ng_ppp 4 , 135.Xr ngctl 8 136.Rs 137.%A K. Hamzeh 138.%A G. Pall 139.%A W. Verthein 140.%A J. Taarud 141.%A W. Little 142.%A G. Zorn 143.%T "Point-to-Point Tunneling Protocol (PPTP)" 144.%O RFC 2637 145.Re 146.Rs 147.%A S. Hanks 148.%A T. \&Li 149.%A D. Farinacci 150.%A P. Traina 151.%T "Generic Routing Encapsulation over IPv4 networks" 152.%O RFC 1702 153.Re 154.Sh HISTORY 155The 156.Nm 157node type was implemented in 158.Fx 4.0 . 159.Sh AUTHORS 160.An Archie Cobbs Aq Mt archie@FreeBSD.org 161.Sh BUGS 162The node should not expect incoming GRE packets to have an IP header. 163This behavior is inherited from the (converse) behavior of raw IP sockets. 164An intermediate node that strips IP headers in one direction 165should be used instead. 166