@@ -57,6 +57,32 @@ int asix_rx_fixup_internal(struct usbnet *dev, struct sk_buff *skb,
int offset = 0;
u16 size;
+ /* When an Ethernet frame spans multiple socket buffers,
+ * do a sanity test for the Data header synchronisation.
+ * Attempt to detect the situation of the previous socket buffer having
+ * been truncated or a socket buffer was missing. These situations
+ * cause a discontinuity in the data stream and therefore need to avoid
+ * appending bad data to the end of the current netdev socket buffer.
+ * Also avoid unnecessarily discarding a good current socket buffer.
+ */
+ if (rx->remaining && (rx->remaining + sizeof(u32) <= skb->len)) {
+ offset = ((rx->remaining + 1) & 0xfffe) + sizeof(u32);
+ rx->header = get_unaligned_le32(skb->data + offset);
+ offset = 0;
+
+ size = (u16) (rx->header & 0x7ff);
+ if (size != ((~rx->header >> 16) & 0x7ff)) {
+ netdev_err(dev->net, "asix_rx_fixup() Data Header synchronisation was lost, remaining %d\n",
+ rx->remaining);
+ kfree_skb(rx->ax_skb);
+ rx->ax_skb = NULL;
+ /* Assume the Data header is at the start of
+ * of the socket buffer.
+ */
+ rx->remaining = 0;
+ }
+ }
+
while (offset + sizeof(u16) <= skb->len) {
u16 copy_length;
unsigned char *data;
Note that the C1 variant of the DUB-E100 USB Ethernet adapter produces "Bad Header" errors. This modification will reduce the number of those error messages and instead provides a more informative reason for the error condition. The consequences of the error are reduced by not consuming bad Ethernet frames and unnecessarily discarding the next Ethernet frame that is probably good. When RX Ethernet frames span multiple socket buffers, the data stream can suffer a discontinuity which will cause the current Ethernet frame in the netdev socket buffer to be incomplete. This frame needs to be discarded instead of appending unrelated data from the current socket buffer to the Ethernet frame in the netdev socket buffer. A discontinuity can occur when the previous socket buffer held an incomplete Ethernet frame due to truncation or a socket buffer containing the end of the Ethernet frame was missing. Therefore, add a sanity test for when an Ethernet frame spans multiple socket buffers to check that the remaining bytes of the currently received Ethernet frame point to a good Data header 32-bit word of the next Ethernet frame. Upon error, reset the remaining byte variable to zero and discard the current netdev socket buffer. Assume that the Data header is located at the start of the current socket buffer and attempt to process the next Ethernet frame from there. This avoids unnecessarily discarding a good socket buffer that contains a new Ethernet frame. Signed-off-by: Dean Jenkins <Dean_Jenkins@mentor.com> --- drivers/net/usb/asix_common.c | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+)