Dear Kohei,
Thank you for your patch.
Am 25.03.26 um 21:50 schrieb Kohei Enju:
i40e advertises IFF_SUPP_NOFCS, allowing users to use the SO_NOFCS
socket option. However, this option is silently ignored, as the driver
does not check skb->no_fcs, and always enables FCS insertion offload.
Fix this by removing the advertisement of IFF_SUPP_NOFCS.
This behavior can be reproduced with a simple AF_PACKET socket:
import socket
s = socket.socket(socket.AF_PACKET, socket.SOCK_RAW)
s.setsockopt(socket.SOL_SOCKET, 43, 1) # SO_NOFCS
s.bind(("eth0", 0))
s.send(b'\xff' * 64)
Previously, send() succeeds but the driver ignores SO_NOFCS.
Would I check that with tcpdump?
With this change, send() fails with -EPROTONOSUPPORT, as expected.
Great commit message! Thank you.
One question, did you look into, what is needed to implement working
SO_NOFC support?
Fixes: 41c445ff0f48 ("i40e: main driver core")
Signed-off-by: Kohei Enju <[email protected]>
---
drivers/net/ethernet/intel/i40e/i40e_main.c | 1 -
1 file changed, 1 deletion(-)
diff --git a/drivers/net/ethernet/intel/i40e/i40e_main.c
b/drivers/net/ethernet/intel/i40e/i40e_main.c
index 3749f32ef95a..a3c52aa6255b 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_main.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_main.c
@@ -13831,7 +13831,6 @@ static int i40e_config_netdev(struct i40e_vsi *vsi)
netdev->neigh_priv_len = sizeof(u32) * 4;
netdev->priv_flags |= IFF_UNICAST_FLT;
- netdev->priv_flags |= IFF_SUPP_NOFCS;
/* Setup netdev TC information */
i40e_vsi_config_netdev_tc(vsi, vsi->tc_config.enabled_tc);
Nice catch.
Kind regards,
Paul
