[PATCH 0/2] Fix CDC_EEM with 802.1Q VLAN and 1500 MTU

cdc_eem USB host driver and gadget driver both are broken in 1500 MTU
case when using 802.1Q VLANs. In both cases, this is due to incomplete
assumptions of Ethernet frame size.

Ian Coolidge (2):
  usb: gadget: g_ether: fix frame size check
  net: usb: cdc_eem: Fix rx skb allocation for 802.1Q VLANs

 drivers/net/usb/cdc_eem.c    |    4 ++++
 drivers/usb/gadget/u_ether.c |    3 ++-
 2 files changed, 6 insertions(+), 1 deletions(-)

-- 
1.7.6.5

Checking skb->len against ETH_FRAME_LEN assumes a 1514
ethernet frame size. With an 802.1Q VLAN header, ethernet
frame length can now be 1518. Validate frame length against that.

Signed-off-by: Ian Coolidge <redacted>
---
 drivers/usb/gadget/u_ether.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/drivers/usb/gadget/u_ether.c b/drivers/usb/gadget/u_ether.c
index 29c854b..ff2c70b 100644
--- a/drivers/usb/gadget/u_ether.c
+++ b/drivers/usb/gadget/u_ether.c

@@ -19,6 +19,7 @@
 #include <linux/ctype.h>
 #include <linux/etherdevice.h>
 #include <linux/ethtool.h>
+#include <linux/if_vlan.h>
 
 #include "u_ether.h"
 

@@ -301,7 +302,7 @@ static void rx_complete(struct usb_ep *ep, struct usb_request *req)
 		while (skb2) {
 			if (status < 0
 					|| ETH_HLEN > skb2->len
-					|| skb2->len > ETH_FRAME_LEN) {
+					|| skb2->len > VLAN_ETH_FRAME_LEN) {
 				dev->net->stats.rx_errors++;
 				dev->net->stats.rx_length_errors++;
 				DBG(dev, "rx length %d\n", skb2->len);

-- 
1.7.6.5

cdc_eem frames might need to contain 802.1Q VLAN Ethernet frames.
Provide this information as an override to usbnet->rx_urb_size

Signed-off-by: Ian Coolidge <redacted>
---
 drivers/net/usb/cdc_eem.c |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)

diff --git a/drivers/net/usb/cdc_eem.c b/drivers/net/usb/cdc_eem.c
index 439690b..63c38dc 100644
--- a/drivers/net/usb/cdc_eem.c
+++ b/drivers/net/usb/cdc_eem.c

@@ -31,6 +31,7 @@
 #include <linux/usb/cdc.h>
 #include <linux/usb/usbnet.h>
 #include <linux/gfp.h>
+#include <linux/if_vlan.h>
 
 
 /*

@@ -94,6 +95,9 @@ static int eem_bind(struct usbnet *dev, struct usb_interface *intf)
 
 	dev->net->hard_header_len += EEM_HEAD + ETH_FCS_LEN;
 
+	/* octets we need to rx for a single ethernet frame */
+	dev->rx_urb_size = EEM_HEAD + ETH_FCS_LEN + VLAN_ETH_FRAME_LEN;
+
 	return 0;
 }
 

-- 
1.7.6.5