[ 3.5.y.z extended stable ] Patch "net: qmi_wwan: prevent duplicate mac address on link" has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    net: qmi_wwan: prevent duplicate mac address on link

to the linux-3.5.y-queue branch of the 3.5.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.5.y-queue

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.5.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From 98164dba76cc1d0dd51bf3e595865156161288c8 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bj=C3=B8rn=20Mork?= <bjorn at mork.no>
Date: Thu, 18 Apr 2013 12:57:11 +0000
Subject: [PATCH] net: qmi_wwan: prevent duplicate mac address on link
 (firmware bug workaround)
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

commit cc6ba5fdaabea7a7b28de3ba1e0fe54d92232fe5 upstream.

We normally trust and use the CDC functional descriptors provided by a
number of devices.  But some of these will erroneously list the address
reserved for the device end of the link.  Attempting to use this on
both the device and host side will naturally not work.

Work around this bug by ignoring the functional descriptor and assign a
random address instead in this case.

Signed-off-by: Bjørn Mork <bjorn at mork.no>
Signed-off-by: David S. Miller <davem at davemloft.net>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/net/usb/qmi_wwan.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/drivers/net/usb/qmi_wwan.c b/drivers/net/usb/qmi_wwan.c
index 83a2a14..7589509 100644
--- a/drivers/net/usb/qmi_wwan.c
+++ b/drivers/net/usb/qmi_wwan.c
@@ -175,6 +175,9 @@ err:
 	return status;
 }

+/* default ethernet address used by the modem */
+static const u8 default_modem_addr[ETH_ALEN] = {0x02, 0x50, 0xf3};
+
 /* Make up an ethernet header if the packet doesn't have one.
  *
  * A firmware bug common among several devices cause them to send raw
@@ -342,6 +345,12 @@ static int qmi_wwan_bind_shared(struct usbnet *dev, struct usb_interface *intf)
 	/* save subdriver struct for suspend/resume wrappers */
 	dev->data[0] = (unsigned long)subdriver;

+	/* Never use the same address on both ends of the link, even
+	 * if the buggy firmware told us to.
+	 */
+	if (!compare_ether_addr(dev->net->dev_addr, default_modem_addr))
+		eth_hw_addr_random(dev->net);
+
 	/* make MAC addr easily distinguishable from an IP header */
 	if (possibly_iphdr(dev->net->dev_addr)) {
 		dev->net->dev_addr[0] |= 0x02;	/* set local assignment bit */
--
1.8.1.2