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authorClaudio Jeker <claudio@cvs.openbsd.org>2004-06-25 04:09:04 +0000
committerClaudio Jeker <claudio@cvs.openbsd.org>2004-06-25 04:09:04 +0000
commit9ec12ec025d2a7005ed46de607f5a6659a3a3cf9 (patch)
treeeb873a91be064de767415169e30a720b0d803bc4 /share/man
parent588e71dad85f222566ed8a308468679172b2068e (diff)
Add tap aka layer 2 tunneling support to tun(4). It can be enabled by setting
the link0 flag via ifconfig(8). OK markus@, canacar@ also tested by ish@
Diffstat (limited to 'share/man')
-rw-r--r--share/man/man4/tun.430
1 files changed, 23 insertions, 7 deletions
diff --git a/share/man/man4/tun.4 b/share/man/man4/tun.4
index e2955ec3e65..3246e35ef90 100644
--- a/share/man/man4/tun.4
+++ b/share/man/man4/tun.4
@@ -1,4 +1,4 @@
-.\" $OpenBSD: tun.4,v 1.27 2003/12/08 10:03:43 markus Exp $
+.\" $OpenBSD: tun.4,v 1.28 2004/06/25 04:09:02 claudio Exp $
.\"
.\" Copyright (c) 2003 Marcus D. Watts All rights reserved.
.\"
@@ -53,13 +53,24 @@ interface can be created at runtime using the
command or by opening the character special device
.Pa /dev/tunN .
.Pp
+Both layer 3 and layer 2 tunnenling is supported.
+Layer 3 tunneling is the default mode, to enable layer 2 tunneling mode the
+.Ar link0
+flag needs to be set with
+.Xr ifconfig 8 .
+In layer 2 mode the
+.Nm
+interface is simulating an Ethernet network interface.
+.Pp
Each device has the exclusive open property; it cannot be opened
if it is already open and in use by another process.
Each read returns at most one packet; if insufficient
buffer space is provided, the packet is truncated.
Each write supplies exactly one packet.
Each packet read or written is prefixed with a tunnel header consisting of
-a 4 byte network byte order integer containing the address family.
+a 4 byte network byte order integer containing the address family in the case
+of layer 3 tunneling.
+In layer 2 mode the 4 byte tunnel header is replaced with a Ethernet header.
On the last close of the device, all packets are discarded,
the device is marked down, and all routes via the device
are removed.
@@ -120,13 +131,16 @@ Can be used to set non-blocking I/O.
Can be used to cause signal
.Dv SIGIO
to be sent when a packet can be read.
-.It Dv TIOCSPGRP Fa int *pgpp
+.It Dv TIOCSPGRP Fa int *pgrp
.It Dv TIOCGPGRP Fa int *pgrp
Get or set the process group to which signals might be sent
via
.Dv FIOASYNC .
.It Dv FIONREAD Fa int *count
Gets the byte count of the next packet available to be read.
+.It Dv SIOCGIFADDR Fa struct ether_addr *addr
+.It Dv SIOCSIFADDR Fa struct ether_addr *addr
+Get or set the ethernet address of the device in layer 2 mode.
.El
.Sh FILES
.Bl -tag -width /dev/tun* -compact
@@ -164,16 +178,18 @@ recognized.
.Pp
Ioctl commands may fail with:
.Bl -tag -width Er
-.It Bq EBUSY
-.Dv TUNSIFMODE
-and the interface was up.
.It Bq EINVAL
Attempt to set both
.Dv IFF_POINTOPOINT
and
.Dv IFF_BROADCAST
with
-.Dv TUNSIFMODE .
+.Dv TUNSIFMODE
+or using
+.Dv SIOCGIFADDR
+or
+.Dv SIOCSIFADDR
+in layer 3 mode.
.It Bq ENOTTY
Unrecognized ioctl command.
.El