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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 .\" .\" $FreeBSD: src/share/man/man4/ng_pptpgre.4,v 1.16.2.2 2002/03/19 18:24:07 schweikh Exp $ .\" $Whistle: ng_pptpgre.8,v 1.2 1999/12/08 00:20:53 archie Exp $ .\" .Dd December 7, 2001 .Dt NG_PPTPGRE 4 .Os .Sh NAME .Nm ng_pptpgre .Nd PPTP GRE protocol netgraph node type .Sh SYNOPSIS .In netgraph/pptpgre/ng_pptpgre.h .Sh DESCRIPTION The .Nm pptpgre node type performs Generic Routing Encapsulation (GRE) over IP for the PPTP protocol as specified by RFC 2637. This involves packet encapsulation, sequencing, acknowledgement, and an adaptive timeout sliding window mechanism. This node type does not handle any of the TCP control protocol or call negotiation defined by PPTP. .Pp This node type expects to receive complete IP packets, including the IP header, on the .Dq Li lower hook, but it transmits outgoing frames without any IP header. The typical use for this node type would be to connect the .Dq Li upper hook to one of the link hooks of a .Xr ng_ppp 4 node, and the .Dq Li lower hook to the .Dq Li "inet/raw/gre" hook of a .Xr ng_ksocket 4 node. .Sh HOOKS This node type supports the following hooks: .Pp .Bl -tag -compact -width ".Li upper" .It Li upper Connection to the upper protocol layers .It Li lower Connection to the lower protocol layers .El .Sh CONTROL MESSAGES This node type supports the generic control messages, plus the following: .Bl -tag -width indent .It Dv NGM_PPTPGRE_SET_CONFIG This command resets and configures the node for a session. This command takes a .Vt "struct ng_pptpgre_conf" as an argument: .Bd -literal /* Configuration for a session */ struct ng_pptpgre_conf { u_char enabled; /* enables traffic flow */ u_char enableDelayedAck; /* enables delayed acks */ u_char enableAlwaysAck; /* always send ack with data */ u_int16_t cid; /* my call id */ u_int16_t peerCid; /* peer call id */ u_int16_t recvWin; /* peer recv window size */ u_int16_t peerPpd; /* peer packet processing delay (in 1/10 of a second) */ }; .Ed .Pp The .Va enabled field enables traffic flow through the node. The .Va enableDelayedAck field enables delayed acknowledgement (maximum 250 milliseconds), which is a useful optimization and should generally be turned on. .Va enableAlwaysAck field enables sending acknowledgements with every data packet, which is probably helpful as well. The remaining fields are as supplied by the PPTP virtual call setup process. .It Dv NGM_PPTPGRE_GET_CONFIG Returns the current configuration as a .Vt "struct ng_pptpgre_conf" . .It Dv NGM_PPTPGRE_GET_STATS This command returns a .Vt "struct ng_pptpgre_stats" containing various node statistics. .It Dv NGM_PPTPGRE_CLR_STATS This command resets the node statistics. .It Dv NGM_PPTPGRE_GETCLR_STATS This command atomically gets and resets the node statistics, returning a .Vt "struct ng_pptpgre_stats" . .El .Sh SHUTDOWN This node shuts down upon receipt of a .Dv NGM_SHUTDOWN control message, or when both hooks have been disconnected. .Sh SEE ALSO .Xr netgraph 4 , .Xr ng_ksocket 4 , .Xr ng_ppp 4 , .Xr ngctl 8 .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 .Rs .%A S. Hanks .%A T. \&Li .%A D. Farinacci .%A P. Traina .%T "Generic Routing Encapsulation over IPv4 networks" .%O RFC 1702 .Re .Sh HISTORY The .Nm node type was implemented in .Fx 4.0 . .Sh AUTHORS .An Archie Cobbs Aq Mt archie@FreeBSD.org .Sh BUGS The node should not expect incoming GRE packets to have an IP header. This behavior is inherited from the (converse) behavior of raw IP sockets. An intermediate node that strips IP headers in one direction should be used instead.