On 14/4/23 13:37, Akihiko Odaki wrote:
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
through , inclusively.
As QEMU processes packets without CRC, the number of bytes for CRC
need to be subtracted.
Signed-off-by: Akihiko Odaki
---
hw/net/e1000x_common.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/hw/net/e1000x_common.c b/hw/net/e1000x_common.c
index 6cc23138a8..b4dfc74b66 100644
--- a/hw/net/e1000x_common.c
+++ b/hw/net/e1000x_common.c
@@ -142,10 +142,10 @@ bool e1000x_is_oversized(uint32_t *mac, size_t size)
{
/* this is the size past which hardware will
drop packets when setting LPE=0 */
-static const int maximum_ethernet_vlan_size = 1522;
+static const int maximum_ethernet_vlan_size = 1522 - 4;
/* this is the size past which hardware will
drop packets when setting LPE=1 */
-static const int maximum_ethernet_lpe_size = 16 * KiB;
+static const int maximum_ethernet_lpe_size = 16 * KiB - 4;
if ((size > maximum_ethernet_lpe_size ||
(size > maximum_ethernet_vlan_size
IMHO this function could be simplified. Something like:
bool long_packet_enabled = mac[RCTL] & E1000_RCTL_LPE;
size_t oversize = long_packet_enabled ? 16 * KiB : ETH_VLAN_MAXSIZE;
size_t crc32_size = sizeof(uint32_t);
if (mac[RCTL] & E1000_RCTL_SBP) {
return false;
}
if (size + crc32_size > oversize ) {
...
return true;
}
return false;
}
