[3.8.y.z,extended,stable] Patch "net: qmi_wwan: fixup missing ethernet header (firmware bug" has been added to staging queue

diff --git a/drivers/net/usb/qmi_wwan.c b/drivers/net/usb/qmi_wwan.c
index 38734fd..5025ca6 100644
--- a/drivers/net/usb/qmi_wwan.c
+++ b/drivers/net/usb/qmi_wwan.c
@@ -13,6 +13,7 @@ 
 #include <linux/module.h>
 #include <linux/netdevice.h>
 #include <linux/ethtool.h>
+#include <linux/etherdevice.h>
 #include <linux/mii.h>
 #include <linux/usb.h>
 #include <linux/usb/cdc.h>
@@ -52,6 +53,79 @@  struct qmi_wwan_state {
 	struct usb_interface *data;
 };

+/* Make up an ethernet header if the packet doesn't have one.
+ *
+ * A firmware bug common among several devices cause them to send raw
+ * IP packets under some circumstances.  There is no way for the
+ * driver/host to know when this will happen.  And even when the bug
+ * hits, some packets will still arrive with an intact header.
+ *
+ * The supported devices are only capably of sending IPv4, IPv6 and
+ * ARP packets on a point-to-point link. Any packet with an ethernet
+ * header will have either our address or a broadcast/multicast
+ * address as destination.  ARP packets will always have a header.
+ *
+ * This means that this function will reliably add the appropriate
+ * header iff necessary, provided our hardware address does not start
+ * with 4 or 6.
+ */
+static int qmi_wwan_rx_fixup(struct usbnet *dev, struct sk_buff *skb)
+{
+	__be16 proto;
+
+	/* usbnet rx_complete guarantees that skb->len is at least
+	 * hard_header_len, so we can inspect the dest address without
+	 * checking skb->len
+	 */
+	switch (skb->data[0] & 0xf0) {
+	case 0x40:
+		proto = htons(ETH_P_IP);
+		break;
+	case 0x60:
+		proto = htons(ETH_P_IPV6);
+		break;
+	default:
+		/* pass along other packets without modifications */
+		return 1;
+	}
+	if (skb_headroom(skb) < ETH_HLEN)
+		return 0;
+	skb_push(skb, ETH_HLEN);
+	skb_reset_mac_header(skb);
+	eth_hdr(skb)->h_proto = proto;
+	memset(eth_hdr(skb)->h_source, 0, ETH_ALEN);
+	memcpy(eth_hdr(skb)->h_dest, dev->net->dev_addr, ETH_ALEN);
+	return 1;
+}
+
+/* very simplistic detection of IPv4 or IPv6 headers */
+static bool possibly_iphdr(const char *data)
+{
+	return (data[0] & 0xd0) == 0x40;
+}
+
+/* disallow addresses which may be confused with IP headers */
+static int qmi_wwan_mac_addr(struct net_device *dev, void *p)
+{
+	struct sockaddr *addr = p;
+
+	if (!is_valid_ether_addr(addr->sa_data) ||
+	    possibly_iphdr(addr->sa_data))
+		return -EADDRNOTAVAIL;
+	memcpy(dev->dev_addr, addr->sa_data, ETH_ALEN);
+	return 0;
+}
+
+static const struct net_device_ops qmi_wwan_netdev_ops = {
+	.ndo_open		= usbnet_open,
+	.ndo_stop		= usbnet_stop,
+	.ndo_start_xmit		= usbnet_start_xmit,
+	.ndo_tx_timeout		= usbnet_tx_timeout,
+	.ndo_change_mtu		= usbnet_change_mtu,
+	.ndo_set_mac_address	= qmi_wwan_mac_addr,
+	.ndo_validate_addr	= eth_validate_addr,
+};
+
 /* using a counter to merge subdriver requests with our own into a combined state */
 static int qmi_wwan_manage_power(struct usbnet *dev, int on)
 {
@@ -229,6 +303,12 @@  next_desc:
 		usb_driver_release_interface(driver, info->data);
 	}

+	/* 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 */
+		dev->net->dev_addr[0] &= 0xbf;	/* clear "IP" bit */
+	}
+	dev->net->netdev_ops = &qmi_wwan_netdev_ops;
 err:
 	return status;
 }
@@ -307,6 +387,7 @@  static const struct driver_info	qmi_wwan_info = {
 	.bind		= qmi_wwan_bind,
 	.unbind		= qmi_wwan_unbind,
 	.manage_power	= qmi_wwan_manage_power,
+	.rx_fixup       = qmi_wwan_rx_fixup,
 };

 #define HUAWEI_VENDOR_ID	0x12D1