.TH VDETAPLIB 1 "December 6, 2006" "Virtual Distributed Ethernet"
.SH NAME
vdetaplib \- Virtual Distributed Ethernet tap emulation library
.SH SYNOPSIS
No synopsis

.br
.SH DESCRIPTION
\fBvdetaplib\fP 
is a library that emulates tap (tuntap level2 interface, see
in kernel sources Documentation/networking/tun.c) and connects
tap virtual interfaces to vde networks.

To use it, the libvdetab.so library must be preloaded
(sh, ksh or bash syntax):
.RS
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.B 
export LD_PRELOAD=/usr/lib/vde2/libvdetap.so
.RE
(csh, tcsh syntax):
.RS
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.B
setenv LD_PRELOAD /usr/lib/vde2/libvdetap.so
.RE

If you want to divert all tap requests to a single vde_switch set the
variable VDEALLTAP to the vde socket. 
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(sh, ksh or bash syntax):
.RS
.br
.B
export VDEALLTAP=/tmp/vde.ctl
.RE
(csh, tcsh syntax):
.RS
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.B
setenv VDEALLTAP /tmp/vde.ctl
.RE

It is possible to set each single interface to different vde_switches
by setting the environment variable with the same name of the interface.
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(sh, ksh or bash syntax):
.RS
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.B
export tap0=/tmp/vde.ctl
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.B
export tap1=/tmp/myvde.ctl
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.B
export ppc=/tmp/ppc.ctl
.RE
(csh, tcsh syntax):
.RS
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.B
setenv tap0 /tmp/vde.ctl
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.B
setenv tap1 /tmp/myvde.ctl
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.B
setenv ppc /tmp/ppc.ctl
.RE
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It is also possible to specify \fBport\fP, \fBgroup\fP or \fBmode\fP for a given
interface setting environment variables as in the following example.
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(sh, ksh or bash syntax):
.RS
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.B
export tap0_port=5
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.B
export tap0_group=vde-net
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.B
export tap0_mode=0660
.RE
(csh, tcsh, syntax):
.RS
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.B
setenv tap0_port 5
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.B
setenv tap0_group vde-net
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.B
setenv tap0_mode 0660
.RE
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The variable to set the specific interface is checked first then
VDEALLTAP. VDEALLTAP thus works as a default choice for the vde switch
to be used.
If VDEALLTAP is not set and there is no specific environment variable
(and for tun -- IFF_TUN interfaces) the kernel provided interface is used.
In this latter case access to /dev/net/tun is required, generally root access.
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.SH NOTICE
Virtual Distributed Ethernet is not related in any way with
www.vde.com ("Verband der Elektrotechnik, Elektronik und Informationstechnik"
i.e. the German "Association for Electrical, Electronic & Information
Technologies").

.SH SEE ALSO
\fBvde_switch\fP(1),
\fBvdeq\fP(1).
.br
.SH AUTHOR
VDE is a project by Renzo Davoli <renzo@cs.unibo.it>