e1000x: Take CRC into consideration for size check

Section 13.7.15 Receive Length Error Count says:
>  Packets over 1522 bytes are oversized if LongPacketEnable is 0b
> (RCTL.LPE). If LongPacketEnable (LPE) is 1b, then an incoming packet
> is considered oversized if it exceeds 16384 bytes.

> These lengths are based on bytes in the received packet from
> <Destination Address> through <CRC>, inclusively.

As QEMU processes packets without CRC, the number of bytes for CRC
need to be subtracted. This change adds some size definitions to be used
to derive the new size thresholds to eth.h.

Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>

1 files changed, 5 insertions, 5 deletions

diff --git a/hw/net/e1000x_common.c b/hw/net/e1000x_common.c
index 6cc23138a8..212873fd77 100644
--- a/hw/net/e1000x_common.c
+++ b/hw/net/e1000x_common.c
@@ -140,16 +140,16 @@ bool e1000x_hw_rx_enabled(uint32_t *mac)
 
 bool e1000x_is_oversized(uint32_t *mac, size_t size)
 {
+    size_t header_size = sizeof(struct eth_header) + sizeof(struct vlan_header);
     /* this is the size past which hardware will
        drop packets when setting LPE=0 */
-    static const int maximum_ethernet_vlan_size = 1522;
+    size_t maximum_short_size = header_size + ETH_MTU;
     /* this is the size past which hardware will
        drop packets when setting LPE=1 */
-    static const int maximum_ethernet_lpe_size = 16 * KiB;
+    size_t maximum_large_size = 16 * KiB - ETH_FCS_LEN;
 
-    if ((size > maximum_ethernet_lpe_size ||
-        (size > maximum_ethernet_vlan_size
-            && !(mac[RCTL] & E1000_RCTL_LPE)))
+    if ((size > maximum_large_size ||
+        (size > maximum_short_size && !(mac[RCTL] & E1000_RCTL_LPE)))
         && !(mac[RCTL] & E1000_RCTL_SBP)) {
         e1000x_inc_reg_if_not_full(mac, ROC);
         trace_e1000x_rx_oversized(size);