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<!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML//EN">
<html>
  <head>
    <title>LINUX VLAN + Cisco HOWTO</title>
  </head>

  <body bgcolor=#ffffff text=#000000>
    <center><h1>LINUX VLAN + Cisco HOWTO</h1></center>
<P>
<center>0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-0</center>
<pre>

  The Linux VLAN HOWTO
 
  VLAN Mailing list: <a href="mailto:vlan@candelatech.com">vlan@candelatech.com</a>
  Kristjan Kotkas <a href="mailto:kristjan@data.ee">kristjan@data.ee</a>
  Ben Greear <a href="mailto:greearb@candelatech.com">greearb@candelatech.com</a>

</pre>
<P>

<b>NOTE:  If you can get ping to work, but telnet/http/ssh/etc hangs, then you most
likely have a driver that is broken with regard to 802.1Q vlans.  There are various
patches for different drivers below.  As a last ditch effort, you can set the MTU
on your VLAN interface to 1496 as opposed to 1500.  If you are unaware of the
consequences of such a thing, please consider getting supported hardware and/or
ask the writer of your driver for a patch. --Ben
</b>
<P>
<h2>Contents</h2>
<ol>
  <li><a href="#targ1">Who, why and where</a></li>
  <li><a href="#targ2">Actual info on how to make it work.</a></li>
  <li><a href="#targ3">Specific work-arounds/patches for certain configurations.</a>
    <ul>
     <li><a href="#tulip">Tulip driver patch.</a></li>
     <li><a href="#eepro">eepro100 driver patch.</a></li>
     <li><a href="#syskonnect">SysKonnect sk98lin driver patch.</a></li>
     <li><a href="#3c59x">3c59X driver patch.</a></li>
     <li><a href="#natsemi">natsemi driver patch.</a></li>
     <li><a href="#3c905b">3c509b driver patch.</a></li>
     <li><a href="#pcmcia">pcmcia drivers.</a></li>
    </ul>
  <li><a href="#targ4">Scripts and Recipes.</a></li>
</ol>
<P>

<ol>
 <li><a name="targ1">META</a>
  <ol>
   <li>
	This is the first HOWTO for the "802.1Q VLAN implementation for Linux"<P>
	      
	Homepage: <a href="http://scry.wanfear.com/~greear/vlan.html">http://scry.wanfear.com/~greear/vlan.html</a>
	Mailing List: VLAN@Scry.WANfear.com
   </li>  
   <P>
   <li>Copyright<P>

  This document is part of the Linux HOWTO project. The copyright notice
  is the following: Unless otherwise stated, Linux HOWTO documents are
  copyrighted by their respective authors. Linux HOWTO documents may be
  reproduced and distributed in whole or in part, in any medium physical
  or electronic, as long as this copyright notice is retained on all
  copies. Commercial redistribution is allowed and encouraged; however,
  the author would like to be notified of any such distributions. All
  translations, derivative works, or aggregate works incorporating any
  Linux HOWTO documents must be covered under this copyright notice.
  That is, you may not produce a derivative work from a HOWTO and impose
  additional restrictions on its distribution. Exceptions to these rules
  may be granted under certain conditions; please contact the Linux
  HOWTO coordinator at the address given below. In short, we wish to
  promote dissemination of this information through as many channels as
  possible. However, we do wish to retain copyright on the HOWTO
  documents, and would like to be notified of any plans to redistribute
  the HOWTOs. If you have questions, please contact Tim Bynum, the Linux
  HOWTO coordinator, at linux-howto@sunsite.unc.edu via email.
   </li>
   <P>
   <li>Disclaimer<P>

  As usual: the author IS NOT responsible for any damage. For the correct
  wording, see the relevant part of the GNU GPL 0.1.1
   </li>
   <P>
   <li>Credits<P>

  Thanks to Ben Greear <a href="http://www.candelatech.com/~greear">http://www.candelatech.com/~greear</a>
  for the VLAN project and also to all the people who have contributed to the project.
   </li>
   <P>
   <li>General<P>

  What is VLAN is not described in this document. Info on the VLAN protocol
  can be found at
   <a href="http://standards.ieee.org/getieee802/download/802.1Q-1998.pdf">http://standards.ieee.org/getieee802/download/802.1Q-1998.pdf</a>.
   </li>
  </ol>
 </li>
 <P>
 <li><a name="targ2"><b>Software/Hardware (Cisco-specific setup, with some general info as well.)</b></a><P>
  <ol>
   <li>VLAN installation & Configuration on the Linux Side.<P>
<PRE>

NOTE:  This is fairly old.  I'm leaving it in for historical reasons, but
be aware that VLAN is included in the later 2.4 kernels, so most folks do
NOT have to patch their kernel. --Ben


* Linux kernel 2.2.14
* Vlan 0.0.10 Patched into it
* Cisco Catalyst 2900XL
* 3Com 3C509B NIC using patched driver 3c59x


Currently VLAN is not part of the kernel distribution so you need to patch
it into a supported Linux kernel and re-compile.

You need the kernel source.  If you don't have it already, you can get from
ftp.kernel.org or from one of its mirrors.  If this scares you, read the
KERNEL-HOWTO.

It is assumed that you have the linux kernel source extracted, and found at:
$HOME/linux  If your setup is different, then some of these commands may
need to be slightly different.

Download the VLAN package from the vlan homepage and extract it's contents.
tar -xvzf vlan*.tar.gz

Go to the vlan directory, build the vlan tools by just typing:
make

After this you get a programm named &lt;vconfig>. This program manages all VLAN
specific configurations.

Now patch the kernel.
Go to the linux directory 
cd linux
(if you installed the kernel source from some rpm based distribution it is 
something like /usr/src/linux)
patch the kernel by typing:

patch -p 1 &lt; $HOME/vlan/vlan.patch (patch is in the vlan directory)

Time to compile your kernel. Use the make menuconfig command in your
linux directory to select your kernel options. The option related to
802.1Q VLANs is found under the Networking options.

Additional help for kernel compilation can be found in KERNEL-HOWTO

Assuming your kernel compiled cleanly, you are now ready to use it. 
Install your kernel in the normal manner (fix up your /etc/lilo.conf file 
appropriately and run lilo as root.) 
Reboot your computer and choose your new kernel. 

As your computer comes back to life, there will be little sign that you are
now 802.1Q capable.
You should see something like this:

        802.1Q VLAN Support v0.10  Ben Greear &lt;greearb@candelatech.com>
        vlan Initialization complete.


Your system is now vlan ready, lets configure some vlans:
I'm assuming that your VLAN capable network card is eth0.

First, set the eth0 state to down:

ifconfig eth0 down
</pre>

<b>Ben's Note: &nbsp;  Regarding the next section, you can run plain ethernet
and VLAN over the same NIC, but you may not want to..</b><pre>
Whatever your previous netconf was, you should move everything to vlans.
This means, that you don't set ip address to the real interface, but set it to
vlan interface. To set your eth0 with no ip:

ifconfig eth0 0.0.0.0 up

!note!
YOU MUST SET THE ETH0 TO UP, or it wont work. (ifconfig eth0 up)

Add some vlans; goto your vlan directory where you previously compiled 
vconfig and type:

vconfig add eth0 2

! Little note about VLAN 1. In Cisco systems it is the default VLAN
so you MUST start using vlans from 2.

This will create device vlan0002 to your system. Linux will think, that it
is just another network device, so you can configure it like any other. Also
you should see the interface by typing

ifconfig -a

Lets make some conf on the vlan then:
ifconfig -i vlan0002 10.0.231.1 broadcast 10.0.231.0 netmask 255.255.255.0 up

This ends the configuration at the linux side.
</pre>
</li>
<P>
<li> Specific Extreme Networks Configuration<P><pre>
  From: Craig Metz: cmetz@inner.net

Extreme configuration example:

  create vlan v42
  config vlan v42 tag 42
  config vlan v42 add port 10 tagged

  ... will create a vlan named v42, whose 802.1Q tag is 42, and connect port
10 (tag 42) to that vlan.
</pre>
</li>
<P>
<li> Cisco-specific configuration<P>
<pre>
Cisco Conf
configure the port you want to use as the trunk:

telnet switch or use the console port

ena
(will prompt for password, so have it ready)

conf t
interface FastEthernet0/24 (it doesnt have to be 0/24)
 duplex full
 speed 100
 switchport trunk encapsulation dot1q
 switchport trunk allowed vlan 2
 switchport mode trunk


This conf will do the following:

Set the port to full duplex mode; force the port to 100Mb mode; set the port
vlan encapsulation to support 802.1Q; tell the
switch that the port is allowed to run vlans through (even if you set just
VLAN 2, cisco will automatically add VLAN 1 and VLAN 1002-1005) to the port 
and set the port to trunk mode aswell. Trunk mode tells the switch that 
a number of VLANS can go through it.

Last line is usually the mother of all screw-ups. If you forget that, you
won't get your VLAN working. Simple as that.

Now configure some other port to be used as the destination for the vlan:

conf t
interface FastEthernet0/1
 duplex half
 speed 10
 switchport access vlan 2
end

Here we tell the switch to force the port 1 to half duplex 10Mb mode (normal
10 Mb NIC) and only traffic from interface VLAN 2 can go through this port.
also you can use a number of ports with VLAN 2, like a HUB ;)

You should now connect some other device to port 1.

Let it have an ip of eg. 10.0.231.2 mask 255.255.255.0

Ping linux from it

ping 10.0.231.1

If it replies scream: "YESS!!" This means, that VLAN is working.

Hard truth: It's not over, till its over.
if this works, then you are out of the woods, if not, well I hear that
tcpdump is a good tool ;-) and tcpdump that came with the vlan package even
better tool. (if you want to dump, use the one that came with vlan package)
</PRE>
<b> NOTE:  <a href="http://ethereal.zing.org">Ethereal</a> also supports VLANs,
and is much more beautiful than tcpdump, if you have GUI capabilities.</b>
<pre>

If you can ping the linux and from linux the host, you should try the
following at linux side:

ping -s 1476 10.0.231.2

If there is no reply, there is something foggy with the NIC. and you
should start debugging.  If ping -s 100 10.0.231.2 works, then it is most likely
an MTU problem with your NIC/Driver.
</PRE>
</li>
</ol>
</li>
<P>
<li><a name="targ3"><h3>Specific patches and work-arounds for various configurations.</h3></a><P>
 <ol>

<a name="tulip">
  <li><B>My Tulip-based card has MTU problems.</B><P>
<pre>

   Here is a patch sent in by Ben McKeegan:
Dear VLAN list members,

Courtesy of my new employer, I've finally got around to updating my tulip
vlan patch for use with linux 2.4.x.  I've also taken the opportunity to
do a rewrite and fix various (non-critical) flaws in my previous patch
(which was against 2.2.x).  The patch allows the driver to receive vlan
frames with maximum MTU.

Hopefully this rewrite will help satisfy some of the concerns of the 2.4
kernel driver maintainers and thus aid inclusion of the patch in the
main driver.

The old patch would erroneously allow incoming frames sized between 1519
and 1536 bytes excluding the CRC.  The new patch should correctly limit
this to 1518, the maximum size for VLANs.  The old patch also needlessly
increased various constants.

I believe there was some suggestion that the old patch disabled all length
error checking and opened the system to DoS attacks from massively
oversized packets.  This is was never really the case, although the above
mentioned bug did exist.  The patch only disabled checking of the 'Frame
Too Long' flag which indicates the frame exceeds 1518 bytes (including the
CRC).  The NIC does not take any special action when this flag is set and
it does not stop the buffers getting filled up - the protection against
DoS comes from the receive timer which has a separate error flag that gets
set when length exceeds 2048 bytes.  The 'Frame Too Long' flag is
basically just a summary of the length bits that are passed as part of the
same descriptor as the flag.  The patch just explicitly checks the length
instead of relying on the flag.

The unpatched driver uses 'magic number' constants to check the receive
status code.  Having worked out what these meant from the documentation,
in the old patch I replaced them with a similar magic number.  The new
patch replaces them with a series of verbose enumerations.  Any worthwhile
compiler should optimize these down to a single constant, but these make
the code much easier to read.  (In fact, its a lot easier to tell what the
patched driver does than what the unpatched driver does. 

I have tested the new patch on our own systems (using chipset 21143 rev
65), and it works ok, but I would appreciate feedback from other people.  
With a lot of testing and a bit of luck and persuasion this patch might
make it into the kernel.

Ben, I would be grateful if you could update the section of your how-to
containing my old patch, and add a note about the problems with the old
patch alongside it.  (Perhaps someone else may wish to backport the new
patch to 2.2)


Regards,

Ben McKeegan.


diff -ur linux-2.4.19/drivers/net/tulip/interrupt.c linux-2.4.19-tulip-vlan/drivers/net/tulip/interrupt.c
--- linux-2.4.19/drivers/net/tulip/interrupt.c	Fri Nov  9 21:45:35 2001
+++ linux-2.4.19-tulip-vlan/drivers/net/tulip/interrupt.c	Mon Sep 16 13:17:40 2002
@@ -122,14 +122,36 @@
 	/* If we own the next entry, it is a new packet. Send it up. */
 	while ( ! (tp->rx_ring[entry].status & cpu_to_le32(DescOwned))) {
 		s32 status = le32_to_cpu(tp->rx_ring[entry].status);
+		short pkt_len;
 
 		if (tulip_debug > 5)
 			printk(KERN_DEBUG "%s: In tulip_rx(), entry %d %8.8x.\n",
 				   dev->name, entry, status);
 		if (--rx_work_limit < 0)
-			break;
-		if ((status & 0x38008300) != 0x0300) {
-			if ((status & 0x38000300) != 0x0300) {
+		        break;
+			
+		/*
+		  Omit the four octet CRC from the length.
+		  (May not be considered valid until we have
+		  checked status for RxLengthOver2047 bits)
+                */
+		pkt_len = ((status >> 16) & 0x7ff) - 4;
+
+		/*
+		  Maximum pkt_len is 1518 (1514 + vlan header)
+		  Anything higher than this is always invalid
+		  regardless of RxLengthOver2047 bits
+		*/
+
+		if ((status & (RxLengthOver2047 |
+			       RxDescCRCError |
+			       RxDescCollisionSeen |
+			       RxDescRunt |
+			       RxDescDescErr |
+			       RxWholePkt))        != RxWholePkt
+		    || pkt_len > 1518 ) {
+			if ((status & (RxLengthOver2047 |
+				       RxWholePkt))         != RxWholePkt) {
 				/* Ingore earlier buffers. */
 				if ((status & 0xffff) != 0x7fff) {
 					if (tulip_debug > 1)
@@ -138,31 +160,21 @@
 							   dev->name, status);
 					tp->stats.rx_length_errors++;
 				}
-			} else if (status & RxDescFatalErr) {
+			} else {
 				/* There was a fatal error. */
 				if (tulip_debug > 2)
 					printk(KERN_DEBUG "%s: Receive error, Rx status %8.8x.\n",
 						   dev->name, status);
 				tp->stats.rx_errors++; /* end of a packet.*/
-				if (status & 0x0890) tp->stats.rx_length_errors++;
+				if (pkt_len > 1518 ||
+				    status & RxDescRunt) tp->stats.rx_length_errors++;
 				if (status & 0x0004) tp->stats.rx_frame_errors++;
 				if (status & 0x0002) tp->stats.rx_crc_errors++;
 				if (status & 0x0001) tp->stats.rx_fifo_errors++;
 			}
 		} else {
-			/* Omit the four octet CRC from the length. */
-			short pkt_len = ((status >> 16) & 0x7ff) - 4;
 			struct sk_buff *skb;
 
-#ifndef final_version
-			if (pkt_len > 1518) {
-				printk(KERN_WARNING "%s: Bogus packet size of %d (%#x).\n",
-					   dev->name, pkt_len, pkt_len);
-				pkt_len = 1518;
-				tp->stats.rx_length_errors++;
-			}
-#endif
-
 #ifdef CONFIG_NET_HW_FLOWCONTROL
                         drop = atomic_read(&netdev_dropping);
                         if (drop)
diff -ur linux-2.4.19/drivers/net/tulip/tulip.h linux-2.4.19-tulip-vlan/drivers/net/tulip/tulip.h
--- linux-2.4.19/drivers/net/tulip/tulip.h	Fri Nov  9 21:45:35 2001
+++ linux-2.4.19-tulip-vlan/drivers/net/tulip/tulip.h	Mon Sep 16 11:55:33 2002
@@ -186,11 +186,44 @@
 
 enum desc_status_bits {
 	DescOwned = 0x80000000,
-	RxDescFatalErr = 0x8000,
+
+        /* 
+	   Error summary flag is logical or of 'CRC Error',
+	   'Collision Seen', 'Frame Too Long', 'Runt' and 
+	   'Descriptor Error' flags generated within tulip chip.
+	*/
+        RxDescErrorSummary = 0x8000, 
+	
+	RxDescCRCError = 0x0002,
+        RxDescCollisionSeen = 0x0040,
+	
+        /* 
+	   'Frame Too Long' flag is set if packet length including CRC
+	   exceeds 1518.  However, a full sized VLAN tagged frame is
+	   1522 bytes including CRC.
+	   
+	   The tulip chip does not block oversized frames, and if this
+	   flag is set on a receive descriptor it does not indicate
+	   the frame has been truncated.  The receive descriptor also
+	   includes the actual length.  Therefore we can safety ignore
+	   this flag and check the length ourselves. 
+        */
+        RxDescFrameTooLong = 0x0080,
+	RxDescRunt = 0x0800,
+	RxDescDescErr = 0x4000,
 	RxWholePkt = 0x0300,
+	
+	/*
+	  Top three bits of 14 bit frame length (status bits 27-29) 
+          should never be set as that would make frame over 2047 bytes.
+	  The Receive Watchdog flag (bit 4) may indicate the length is
+          over 2048 and the length field is invalid.
+	*/
+	RxLengthOver2047 = 0x38000010
 };
 
 
+
 enum t21041_csr13_bits {
 	csr13_eng = (0xEF0<<4), /* for eng. purposes only, hardcode at EF0h */
 	csr13_aui = (1<<3), /* clear to force 10bT, set to force AUI/BNC */

</pre>
</li>

<a name="eepro">
  <li><B>My eepro100 has MTU problems.</B><P>

NOTE:  Intel's e100 driver works out-of-the-box. --Ben
<P>

   Here is a patch sent in by gleb@nbase.co.il<br>

<pre>
     filename="linux-2.2.14-eepro100-vlan.patch"

--- linux/drivers/net/eepro100.c        Tue Oct 26 20:53:40 1999
+++ linux1/drivers/net/eepro100.c       Sun May 14 07:47:34 2000
@@ -377,12 +377,12 @@
 const char i82557_config_cmd[22] = {
        22, 0x08, 0, 0,  0, 0x80, 0x32, 0x03,  1, /* 1=Use MII  0=Use AUI */
        0, 0x2E, 0,  0x60, 0,
-       0xf2, 0x48,   0, 0x40, 0xf2, 0x80,              /* 0x40=Force full-duplex */
+       0xf2, 0x48,   0, 0x40, 0xfa, 0x80,              /* 0x40=Force full-duplex */
        0x3f, 0x05, };
 const char i82558_config_cmd[22] = {
        22, 0x08, 0, 1,  0, 0x80, 0x22, 0x03,  1, /* 1=Use MII  0=Use AUI */
        0, 0x2E, 0,  0x60, 0x08, 0x88,
-       0x68, 0, 0x40, 0xf2, 0xBD,              /* 0xBD->0xFD=Force full-duplex */
+       0x68, 0, 0x40, 0xfa, 0xBD,              /* 0xBD->0xFD=Force full-duplex */
        0x31, 0x05, };
 
 /* PHY media interface chips. */
</pre>
</li>
<P>
<a name="syskonnect">
<li><B>My SysKonnect sk98lin doesn't work</b> (submitted by:  Patrick Schaaf &lt;bof@bof.de>)<P>

Here's a piece needed to get SysKonnect sk98lin
driven cards to play nice; they recognize and drop incoming VLAN tagged
frames in the driver, the patch below removes that check. Tested a bit
with a Cisco Catalyst 6509 on the other side, and a fibre link, works
like a charm. The card and driver already supports MTUs up to over 9000,
so no problem on that side.
<P>
<PRE>
diff -urN linux/drivers/net/sk98lin/skge.c blues/drivers/net/sk98lin/skge.c
--- linux/drivers/net/sk98lin/skge.c    Mon Jun 19 20:42:38 2000
+++ blues/drivers/net/sk98lin/skge.c    Mon Aug  7 09:43:18 2000
@@ -1948,7 +1948,7 @@
                
                if ((Control & RX_CTRL_STAT_VALID) == RX_CTRL_STAT_VALID &&
                        (FrameStat & 
-                       (XMR_FS_ANY_ERR | XMR_FS_1L_VLAN | XMR_FS_2L_VLAN))
+                       (XMR_FS_ANY_ERR /*| XMR_FS_1L_VLAN*/ | XMR_FS_2L_VLAN))
                         == 0) {
                        SK_DBG_MSG(NULL, SK_DBGMOD_DRV,
                                SK_DBGCAT_DRV_RX_PROGRESS,("V"));

</pre>
</li>
<P>
<a name="3c59x">
<li><b>My 3C59X has MTU problems.</b><P>

Various contributors, most recently: Richard Fuchs

<pre>

--- 3c59x.c-ori	2003-07-02 15:26:26.000000000 +0200
+++ 3c59x.c	2003-07-02 15:40:26.000000000 +0200
@@ -308,6 +308,9 @@
    code size of a per-interface flag is not worthwhile. */
 static char mii_preamble_required;
 
+/* The Ethernet Type used for 802.1q tagged frames */
+#define VLAN_ETHER_TYPE 0x8100
+
 #define PFX DRV_NAME ": "
 
 
@@ -655,7 +658,7 @@
 	Wn2_ResetOptions=12,
 };
 enum Window3 {			/* Window 3: MAC/config bits. */
-	Wn3_Config=0, Wn3_MAC_Ctrl=6, Wn3_Options=8,
+	Wn3_Config=0, Wn3_MaxPktSize=4, Wn3_MAC_Ctrl=6, Wn3_Options=8,
 };
 
 #define BFEXT(value, offset, bitcount)  \
@@ -683,7 +686,8 @@
 	Media_LnkBeat = 0x0800,
 };
 enum Window7 {					/* Window 7: Bus Master control. */
-	Wn7_MasterAddr = 0, Wn7_MasterLen = 6, Wn7_MasterStatus = 12,
+	Wn7_MasterAddr = 0, Wn7_VlanEtherType=4, Wn7_MasterLen = 6,
+	Wn7_MasterStatus = 12,
 };
 /* Boomerang bus master control registers. */
 enum MasterCtrl {
@@ -780,7 +784,8 @@
 		pm_state_valid:1,				/* power_state[] has sane contents */
 		open:1,
 		medialock:1,
-		must_free_region:1;				/* Flag: if zero, Cardbus owns the I/O region */
+		must_free_region:1,				/* Flag: if zero, Cardbus owns the I/O region */
+		large_frames:1;					/* accept large frames */
 	int drv_flags;
 	u16 status_enable;
 	u16 intr_enable;
@@ -848,6 +853,9 @@
 static int vortex_ioctl(struct net_device *dev, struct ifreq *rq, int cmd);
 static void vortex_tx_timeout(struct net_device *dev);
 static void acpi_set_WOL(struct net_device *dev);
+#if defined(CONFIG_VLAN_8021Q) || defined(CONFIG_VLAN_8021Q_MODULE)
+static void set_8021q_mode(struct net_device *dev, int enable);
+#endif
 
 /* This driver uses 'options' to pass the media type, full-duplex flag, etc. */
 /* Option count limit only -- unlimited interfaces are supported. */
@@ -1031,6 +1039,7 @@
 	dev->base_addr = ioaddr;
 	dev->irq = irq;
 	dev->mtu = mtu;
+	vp->large_frames = mtu > 1500;
 	vp->drv_flags = vci->drv_flags;
 	vp->has_nway = (vci->drv_flags & HAS_NWAY) ? 1 : 0;
 	vp->io_size = vci->io_size;
@@ -1450,7 +1459,7 @@
 
 	/* Set the full-duplex bit. */
 	outw(	((vp->info1 & 0x8000) || vp->full_duplex ? 0x20 : 0) |
-		 	(dev->mtu > 1500 ? 0x40 : 0) |
+		 	(vp->large_frames ? 0x40 : 0) |
 			((vp->full_duplex && vp->flow_ctrl && vp->partner_flow_ctrl) ? 0x100 : 0),
 			ioaddr + Wn3_MAC_Ctrl);
 
@@ -1534,6 +1543,10 @@
 	}
 	/* Set receiver mode: presumably accept b-case and phys addr only. */
 	set_rx_mode(dev);
+#if defined(CONFIG_VLAN_8021Q) || defined(CONFIG_VLAN_8021Q_MODULE)
+	/* enable 802.1q tagged frames */
+	set_8021q_mode(dev, 1);
+#endif
 	outw(StatsEnable, ioaddr + EL3_CMD); /* Turn on statistics. */
 
 //	issue_and_wait(dev, SetTxStart|0x07ff);
@@ -1674,7 +1687,7 @@
 						/* Set the full-duplex bit. */
 						EL3WINDOW(3);
 						outw(	(vp->full_duplex ? 0x20 : 0) |
-								(dev->mtu > 1500 ? 0x40 : 0) |
+								(vp->large_frames ? 0x40 : 0) |
 								((vp->full_duplex && vp->flow_ctrl && vp->partner_flow_ctrl) ? 0x100 : 0),
 								ioaddr + Wn3_MAC_Ctrl);
 						if (vortex_debug > 1)
@@ -1897,6 +1910,10 @@
 			issue_and_wait(dev, RxReset|0x07);
 			/* Set the Rx filter to the current state. */
 			set_rx_mode(dev);
+#if defined(CONFIG_VLAN_8021Q) || defined(CONFIG_VLAN_8021Q_MODULE)
+			/* enable 802.1q VLAN tagged frames */
+			set_8021q_mode(dev, 1);
+#endif
 			outw(RxEnable, ioaddr + EL3_CMD); /* Re-enable the receiver. */
 			outw(AckIntr | HostError, ioaddr + EL3_CMD);
 		}
@@ -2494,6 +2511,11 @@
 	outw(RxDisable, ioaddr + EL3_CMD);
 	outw(TxDisable, ioaddr + EL3_CMD);
 
+#if defined(CONFIG_VLAN_8021Q) || defined(CONFIG_VLAN_8021Q_MODULE)
+	/* Disable receiving 802.1q tagged frames */
+	set_8021q_mode(dev, 0);
+#endif
+
 	if (dev->if_port == XCVR_10base2)
 		/* Turn off thinnet power.  Green! */
 		outw(StopCoax, ioaddr + EL3_CMD);
@@ -2758,6 +2780,50 @@
 	outw(new_mode, ioaddr + EL3_CMD);
 }
 
+#if defined(CONFIG_VLAN_8021Q) || defined(CONFIG_VLAN_8021Q_MODULE)
+/* Setup the card so that it can receive frames with an 802.1q VLAN tag.
+   Note that this must be done after each RxReset due to some backwards
+   compatibility logic in the Cyclone and Tornado ASICs */
+static void set_8021q_mode(struct net_device *dev, int enable)
+{
+	struct vortex_private *vp = (struct vortex_private *)dev->priv;
+	long ioaddr = dev->base_addr;
+	int old_window = inw(ioaddr + EL3_CMD);
+	int mac_ctrl;
+
+	if (vp->drv_flags&IS_CYCLONE || vp->drv_flags&IS_TORNADO) {
+		/* cyclone and tornado chipsets can recognize 802.1q
+		 * tagged frames and treat them correctly */
+
+		int max_pkt_size = dev->mtu+14;	/* MTU+Ethernet header */
+		if (enable)
+			max_pkt_size += 4;	/* 802.1Q VLAN tag */
+
+		EL3WINDOW(3);
+		outw(max_pkt_size, ioaddr+Wn3_MaxPktSize);
+
+		/* set VlanEtherType to let the hardware checksumming
+		   treat tagged frames correctly */
+		EL3WINDOW(7);
+		outw(VLAN_ETHER_TYPE, ioaddr+Wn7_VlanEtherType);
+	} else {
+		/* on older cards we have to enable large frames */
+
+		vp->large_frames = dev->mtu > 1500 || enable;
+
+		EL3WINDOW(3);
+		mac_ctrl = inw(ioaddr+Wn3_MAC_Ctrl);
+		if (vp->large_frames)
+			mac_ctrl |= 0x40;
+		else
+			mac_ctrl &= ~0x40;
+		outw(mac_ctrl, ioaddr+Wn3_MAC_Ctrl);
+	}
+
+	EL3WINDOW(old_window);
+}
+#endif
+
 /* MII transceiver control section.
    Read and write the MII registers using software-generated serial
    MDIO protocol.  See the MII specifications or DP83840A data sheet

</pre>
</li>
<P>

<a name="natsemi">
<li><b>My natsemi has MTU problems.</b><P>
By Peter Stuge:
<pre>

--- natsemi.c.orig	2002-12-30 21:38:04.000000000 +0100
+++ natsemi.c	2002-12-30 22:25:19.000000000 +0100
@@ -233,7 +233,7 @@
 #define NATSEMI_REGS_SIZE	(NATSEMI_NREGS * sizeof(u32))
 #define NATSEMI_EEPROM_SIZE	24 /* 12 16-bit values */
 
-#define PKT_BUF_SZ		1536 /* Size of each temporary Rx buffer. */
+#define PKT_BUF_SZ		2064 /* Size of each temporary Rx buffer. */
 
 /* These identify the driver base version and may not be removed. */
 static char version[] __devinitdata =
@@ -1290,7 +1290,7 @@
 	/* DRTH 0x10: start copying to memory if 128 bytes are in the fifo
 	 * MXDMA 0: up to 256 byte bursts
 	 */
-	np->rx_config = RxMxdma_256 | 0x20;
+	np->rx_config = RxAcceptLong | RxMxdma_256 | 0x20;
 	writel(np->rx_config, ioaddr + RxConfig);
 
 	/* Disable PME:
</pre>
</li>
<P>

<a name="3c905b">
<li><b>My 3C905B has MTU problems.</b><P>
As found
<a href="http://www.bewley.net/linux/vlan/patches/vlan-3c59x.patch">here</a>
at one point in time.<br>
Furnished by: Luis Miguel Cruz Miranda luismi@b2bi.es<br>
(I don't know the original author --Ben).

<PRE>
--- linux.orig/drivers/net/3c59x.c	Sun Sep 30 21:26:06 2001
+++ linux/drivers/net/3c59x.c	Wed Oct 24 21:52:10 2001
@@ -308,6 +308,9 @@
    code size of a per-interface flag is not worthwhile. */
 static char mii_preamble_required;
 
+/* The Ethernet Type used for 802.1q tagged frames */
+#define VLAN_ETHER_TYPE 0x8100
+
 #define PFX DRV_NAME ": "
 
 
@@ -651,7 +654,7 @@
 	Wn2_ResetOptions=12,
 };
 enum Window3 {			/* Window 3: MAC/config bits. */
-	Wn3_Config=0, Wn3_MAC_Ctrl=6, Wn3_Options=8,
+	Wn3_Config=0, Wn3_MaxPktSize=4, Wn3_MAC_Ctrl=6, Wn3_Options=8,
 };
 
 #define BFEXT(value, offset, bitcount)  \
@@ -679,7 +682,8 @@
 	Media_LnkBeat = 0x0800,
 };
 enum Window7 {					/* Window 7: Bus Master control. */
-	Wn7_MasterAddr = 0, Wn7_MasterLen = 6, Wn7_MasterStatus = 12,
+	Wn7_MasterAddr = 0, Wn7_VlanEtherType=4, Wn7_MasterLen = 6,
+	Wn7_MasterStatus = 12,
 };
 /* Boomerang bus master control registers. */
 enum MasterCtrl {
@@ -776,7 +780,8 @@
 		pm_state_valid:1,				/* power_state[] has sane contents */
 		open:1,
 		medialock:1,
-		must_free_region:1;				/* Flag: if zero, Cardbus owns the I/O region */
+		must_free_region:1,				/* Flag: if zero, Cardbus owns the I/O region */
+		large_frames:1;			/* accept large frames */
 	int drv_flags;
 	u16 status_enable;
 	u16 intr_enable;
@@ -844,6 +849,9 @@
 static int vortex_ioctl(struct net_device *dev, struct ifreq *rq, int cmd);
 static void vortex_tx_timeout(struct net_device *dev);
 static void acpi_set_WOL(struct net_device *dev);
+#if defined(CONFIG_VLAN_8021Q) || defined(CONFIG_VLAN_8021Q_MODULE)
+static void set_8021q_mode(struct net_device *dev, int enable);
+#endif
 
 /* This driver uses 'options' to pass the media type, full-duplex flag, etc. */
 /* Option count limit only -- unlimited interfaces are supported. */
@@ -1030,6 +1038,7 @@
 	dev->base_addr = ioaddr;
 	dev->irq = irq;
 	dev->mtu = mtu;
+	vp->large_frames = mtu > 1500;
 	vp->drv_flags = vci->drv_flags;
 	vp->has_nway = (vci->drv_flags & HAS_NWAY) ? 1 : 0;
 	vp->io_size = vci->io_size;
@@ -1461,7 +1470,7 @@
 
 	/* Set the full-duplex bit. */
 	outw(	((vp->info1 & 0x8000) || vp->full_duplex ? 0x20 : 0) |
-		 	(dev->mtu > 1500 ? 0x40 : 0) |
+		 	(vp->large_frames ? 0x40 : 0) |
 			((vp->full_duplex && vp->flow_ctrl && vp->partner_flow_ctrl) ? 0x100 : 0),
 			ioaddr + Wn3_MAC_Ctrl);
 
@@ -1545,6 +1554,10 @@
 	}
 	/* Set receiver mode: presumably accept b-case and phys addr only. */
 	set_rx_mode(dev);
+#if defined(CONFIG_VLAN_8021Q) || defined(CONFIG_VLAN_8021Q_MODULE)
+	/* enable 802.1q tagged frames */
+	set_8021q_mode(dev, 1);
+#endif
 	outw(StatsEnable, ioaddr + EL3_CMD); /* Turn on statistics. */
 
 //	issue_and_wait(dev, SetTxStart|0x07ff);
@@ -1680,7 +1693,7 @@
 						/* Set the full-duplex bit. */
 						EL3WINDOW(3);
 						outw(	(vp->full_duplex ? 0x20 : 0) |
-								(dev->mtu > 1500 ? 0x40 : 0) |
+								(vp->large_frames ? 0x40 : 0) |
 								((vp->full_duplex && vp->flow_ctrl && vp->partner_flow_ctrl) ? 0x100 : 0),
 								ioaddr + Wn3_MAC_Ctrl);
 						if (vortex_debug > 1)
@@ -1900,6 +1913,10 @@
 			issue_and_wait(dev, RxReset|0x07);
 			/* Set the Rx filter to the current state. */
 			set_rx_mode(dev);
+#if defined(CONFIG_VLAN_8021Q) || defined(CONFIG_VLAN_8021Q_MODULE)
+			/* enable 802.1q VLAN tagged frames */
+			set_8021q_mode(dev, 1);
+#endif
 			outw(RxEnable, ioaddr + EL3_CMD); /* Re-enable the receiver. */
 			outw(AckIntr | HostError, ioaddr + EL3_CMD);
 		}
@@ -2497,6 +2514,11 @@
 	outw(RxDisable, ioaddr + EL3_CMD);
 	outw(TxDisable, ioaddr + EL3_CMD);
 
+#if defined(CONFIG_VLAN_8021Q) || defined(CONFIG_VLAN_8021Q_MODULE)
+	/* Disable receiving 802.1q tagged frames */
+	set_8021q_mode(dev, 0);
+#endif
+
 	if (dev->if_port == XCVR_10base2)
 		/* Turn off thinnet power.  Green! */
 		outw(StopCoax, ioaddr + EL3_CMD);
@@ -2760,6 +2782,50 @@
 
 	outw(new_mode, ioaddr + EL3_CMD);
 }
+
+#if defined(CONFIG_VLAN_8021Q) || defined(CONFIG_VLAN_8021Q_MODULE)
+/* Setup the card so that it can receive frames with an 802.1q VLAN tag.
+   Note that this must be done after each RxReset due to some backwards
+   compatibility logic in the Cyclone and Tornado ASICs */
+static void set_8021q_mode(struct net_device *dev, int enable)
+{
+	struct vortex_private *vp = (struct vortex_private *)dev->priv;
+	long ioaddr = dev->base_addr;
+	int old_window = inw(ioaddr + EL3_CMD);
+	int mac_ctrl;
+	
+	if (vp->drv_flags&IS_CYCLONE || vp->drv_flags&IS_TORNADO) {
+		/* cyclone and tornado chipsets can recognize 802.1q
+		 * tagged frames and treat them correctly */
+
+		int max_pkt_size = dev->mtu+14;	/* MTU+Ethernet header */
+		if (enable)
+			max_pkt_size += 4;	/* 802.1Q VLAN tag */
+
+		EL3WINDOW(3);
+		outw(max_pkt_size, ioaddr+Wn3_MaxPktSize);
+
+		/* set VlanEtherType to let the hardware checksumming
+		   treat tagged frames correctly */
+		EL3WINDOW(7);
+		outw(VLAN_ETHER_TYPE, ioaddr+Wn7_VlanEtherType);
+	} else {
+		/* on older cards we have to enable large frames */
+
+		vp->large_frames = dev->mtu > 1500 || enable;
+
+		EL3WINDOW(3);
+		mac_ctrl = inw(ioaddr+Wn3_MAC_Ctrl);
+		if (vp->large_frames)
+			mac_ctrl |= 0x40;
+		else
+			mac_ctrl &= ~0x40;
+		outw(mac_ctrl, ioaddr+Wn3_MAC_Ctrl);
+	}
+
+	EL3WINDOW(old_window);
+}
+#endif
 
 /* MII transceiver control section.
    Read and write the MII registers using software-generated serial
</pre>
</li>
<P>

<a name="pcmcia">
<li><b>How to make my PCMCIA ethernet card work with VLANs?</b><P>
Per Peter Stuge:<P>

The problem was that the VLAN code in kernel header files weren't included
properly when compiling the PCMCIA stuff.  Exactly why?  I'm not sure, might
be because the PCMCIA stuff isn't the actual kernel and that means it's
missing defines that trigger the VLAN #ifdefs.
<P>
Commenting the #ifdefs in linux/netdevice.h and adding code to clear out
the struct vlan_dev_info* vlan_dev after having created the new network
device in the PCMCIA client for the networking card did the trick if I
remember correctly.  (The reason it doesn't work out-of-the-box is that the
kernel VLAN code has garbage data for the VLAN fields in struct device since
the device creator (PCMCIA client driver) doesn't know about them.)
<P>
Ben Adds:<P>
To clear out the garbage, the PCMCIA driver needs to mset the net_device structure
to zero (it should do this anyway..)  If anyone has a patch, please send it to me
and the owners of the PCMCIA code...
</pre>
</li>

</ol>
</li>
<P>
<li><a name="targ4"><h3>Scripts and Recipes.</h3></a><P>
 <ol>
  <li><B>Mandrake (RedHat-style) startup script for VLANs.</B><P>
   Contributed by: "MaxiM Basunov" &lt;maxim@idknet.com>
<PRE>
#!/bin/sh
#
# network       Bring up/down networking
#
# chkconfig: 2345 10 90
# description: Activates/Deactivates all network interfaces configured to \
#              start at boot time.
# probe: true

# Source function library.
. /etc/init.d/functions

if [ ! -f /etc/sysconfig/network ]; then
    exit 0
fi

. /etc/sysconfig/network

if [ -f /etc/sysconfig/pcmcia ]; then
 . /etc/sysconfig/pcmcia
fi


# Check that networking is up.
[ ${NETWORKING} = "no" ] && exit 0

[ -x /sbin/ifconfig ] || exit 0

# Even if IPX is configured, without the utilities we can't do much
[ ! -x /sbin/ipx_internal_net -o ! -x /sbin/ipx_configure ] && IPX=

CWD=`pwd`
cd /etc/sysconfig/network-scripts

# find all the interfaces besides loopback.
# ignore aliases, alternative configurations, and editor backup files
interfaces=`ls ifcfg* | egrep -v '(ifcfg-lo|:)' | \
            egrep -v 'ifcfg-ippp[0-9]+$' | \
>            egrep 'ifcfg-[a-z0-9\.]+$' | \
&lt;            egrep 'ifcfg-[a-z0-9]+$' | \
            sed 's/^ifcfg-//g'`

# See how we were called.
case "$1" in
  start)

   action "Setting network parameters: " sysctl -p /etc/sysctl.conf

 action "Bringing up interface lo: " ./ifup ifcfg-lo

 case "$IPX" in
   yes|true)
     /sbin/ipx_configure --auto_primary=$IPXAUTOPRIMARY \
       --auto_interface=$IPXAUTOFRAME
     if [ "$IPXINTERNALNETNUM" != "0" ]; then
        /sbin/ipx_internal_net add $IPXINTERNALNETNUM $IPXINTERNALNODENUM
     fi
     ;;
 esac
 # depreciated but we still use it.
 if [ -f /proc/sys/net/ipv4/ip_forward ] && [ "$FORWARD_IPV4" = "yes" ] ||
 "$FORWARD_IPV4" = "true" ];
     then
  action "Enabling IPv4 packet forwarding" sysctl -w net.ipv4.ip_forward=1
 fi

> action "Setting VLAN parameters: " vconfig set_name_type DEV_PLUS_VID

 for i in $interfaces; do
  if egrep -L "^ONBOOT=\"?[Nn][Oo]\"?" ifcfg-$i >/dev/null 2>&1; then
   # Probe module to preserve interface ordering
   /sbin/ifconfig $i >/dev/null 2>&1
  else
>   vlan=`echo $i | egrep -v '(lo|:)' | \
>        egrep -v 'ippp[0-9]+$' | \
>        egrep '[a-z0-9]+\.[0-9][0-9][0-9][0-9]$' | \
>        sed "s/^[a-z0-9]*\.//g;s/^0*//g"`
>   ifvlan=`echo $i | egrep -v '(lo|:)' | \
>        egrep -v 'ippp[0-9]+$' | \
>           egrep '[a-z0-9]+\.[0-9][0-9][0-9][0-9]$' | \
>        sed "s/\.[a-z0-9]*$//g"`

>   if [ -n "${vlan}" ]; then
>    action "Enable ${vlan} on {$ifvlan}: " vconfig add ${ifvlan} ${vlan}
>   fi
   action "Bringing up interface $i: " ./ifup $i boot
  fi
 done

 # Add non interface-specific static-routes.
 if [ -f /etc/sysconfig/static-routes ]; then
    grep "^any" /etc/sysconfig/static-routes | while read ignore type dest
netmask mask bogus args; do
       if [ "${bogus}" = "gw" ]; then
        /sbin/route add -$type $dest $netmask $mask $args
       else
        /sbin/route add -$type $dest $netmask $mask $bogus $args
       fi
    done
 fi

        touch /var/lock/subsys/network
        ;;
  stop)
   # If this is a final shutdown/halt, check for network FS,
 # and unmount them even if the user didn't turn on netfs

 if [ "$RUNLEVEL" = "6" -o "$RUNLEVEL" = "0" -o "$RUNLEVEL" = "1" ]; then
  NFSMTAB=`grep -v '^#' /proc/mounts | awk '{ if ($3 ~ /^nfs$/ ) print $2}'`
  SMBMTAB=`grep -v '^#' /proc/mounts | awk '{ if ($3 ~ /^smbfs$/ ) print
$2}'`
  NCPMTAB=`grep -v '^#' /proc/mounts | awk '{ if ($3 ~ /^ncpfs$/ ) print
$2}'`
  if [ -n "$NFSMTAB" -o -n "$SMBMTAB" -o -n "$NCPMTAB" ] ; then
   /etc/init.d/netfs stop
  fi
 fi

 for i in $interfaces ; do
         if ifconfig $i 2>/dev/null | grep -q "UP" >/dev/null 2>&1 ; then
     action "Shutting down interface $i: " ./ifdown $i boot
  fi
 done
 case "$IPX" in
   yes|true)
     if [ "$IPXINTERNALNETNUM" != "0" ]; then
        /sbin/ipx_internal_net del
     fi
     ;;
 esac
 ./ifdown ifcfg-lo
 if [ -d /proc/sys/net/ipv4 ]; then
   if [ -f /proc/sys/net/ipv4/ip_forward ]; then
  if [ `cat /proc/sys/net/ipv4/ip_forward` != 0 ]; then
   action "Disabling IPv4 packet forwarding: " sysctl -w
net.ipv4.ip_forward=0
  fi
   fi
   if [ -f /proc/sys/net/ipv4/ip_always_defrag ]; then
         if [ `cat /proc/sys/net/ipv4/ip_always_defrag` != 0 ]; then
          action "Disabling IPv4 automatic defragmentation: " sysctl -w
net.ipv4.ip_always_defrag=0
  fi
   fi
 fi
 if [ -f /proc/sys/net/ipv4/tcp_syncookies ];then
         if [ `cat /proc/sys/net/ipv4/tcp_syncookies` != 0 ]; then
      sysctl -w net.ipv4.tcp_syncookies=0
  fi
 fi

        rm -f /var/lock/subsys/network
        ;;
  status)
 echo "Configured devices:"
 echo lo $interfaces

 if [ -x /bin/linuxconf ] ; then
  eval `/bin/linuxconf --hint netdev`
  echo "Devices that are down:"
  echo $DEV_UP
  echo "Devices with modified configuration:"
  echo $DEV_RECONF
 else
  echo "Currently active devices:"
  echo `/sbin/ifconfig | grep ^[a-z] | awk '{print $1}'`
 fi
 ;;
  restart)
        cd $CWD
 $0 stop
 $0 start
 ;;
  reload)
 if [ -x /bin/linuxconf ] ; then
  eval `/bin/linuxconf --hint netdev`
  for device in $DEV_UP ; do
   action "Bringing up device $device: " ./ifup $device
  done
  for device in $DEV_DOWN ; do
   action "Shutting down device $device: " ./ifdown $device
  done
  for device in $DEV_RECONF ; do
   action "Shutting down device $device: " ./ifdown $device
   action "Bringing up device $device: " ./ifup $device
  done
  for device in $DEV_RECONF_ALIASES ; do
   action "Briging up alias $device: "
/etc/sysconfig/network-scripts/ifup-aliases $device
  done
  for device in $DEV_RECONF_ROUTES ; do
   action "Bringing up route $device: "
/etc/sysconfig/network-scripts/ifup-routes $device
  done
  case $IPX in yes|true)
    case $IPXINTERNALNET in
      reconf)
   action "Deleting internal IPX network: " /sbin/ipx_internal_net del
   action "Adding internal IPX network $IPXINTERNALNETNUM
$IPXINTERNALNODENUM: " /sbin/ipx_internal_net add $IPXINTERNALNETNUM \
            $IPXINTERNALNODENUM
   ;;
      add)
   action "Adding internal IPX network $IPXINTERNALNETNUM
$IPXINTERNALNODENUM: "/sbin/ipx_internal_net add $IPXINTERNALNETNUM \
            $IPXINTERNALNODENUM
   ;;
      del)
   action "Deleting internal IPX network: " /sbin/ipx_internal_net del
   ;;
    esac
    ;;
  esac
 else
         cd $CWD
  $0 restart
 fi
 ;;
  probe)
 if [ -x /bin/linuxconf ] ; then
  eval `/bin/linuxconf --hint netdev`
  [ -n "$DEV_UP$DEV_DOWN$DEV_RECONF$DEV_RECONF_ALIASES" -o \
    -n "$DEV_RECONF_ROUTES$IPXINTERNALNET" ] && \
   echo reload
  exit 0
 else
  # if linuxconf isn't around to figure stuff out for us,
  # we punt.  Probably better than completely reloading
  # networking if user isn't sure which to do.  If user
  # is sure, they would run restart or reload, not probe.
  exit 0
 fi
 ;;
  *)
        echo "Usage: network {start|stop|restart|reload|status|probe}"
        exit 1
esac

exit 0
</pre>
</li>

</ol>
<P>
<HR>
<pre>
Terv, 

-----------------------------
Kristjan Kotkas 
KPNQwest Estonia
kristjan.kotkas@kpnqwest.ee
t + 372 62 66299 m + 372 51 60697 f + 372 62 66292

</pre>


    <hr>
    <address><a href="mailto:greear@cyberhighway.net">Ben Greear</a></address>
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Last modified: Fri Jul  4 09:53:40 PDT 2003
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