From: Paolo Abeni <pabeni@xxxxxxxxxx> commit 40ee363c844fcb6ae0f1f5cfea68aed7e268c2f4 upstream. Checking tunnel offloading, it turns out that offloading doesn't work as expected. The following script allows to reproduce the issue. Call it as `testscript DEVICE LOCALIP REMOTEIP NETMASK' === SNIP === if [ $# -ne 4 ] then echo "Usage $0 DEVICE LOCALIP REMOTEIP NETMASK" exit 1 fi DEVICE="$1" LOCAL_ADDRESS="$2" REMOTE_ADDRESS="$3" NWMASK="$4" echo "Driver: $(ethtool -i ${DEVICE} | awk '/^driver:/{print $2}') " ethtool -k "${DEVICE}" | grep tx-udp echo echo "Set up NIC and tunnel..." ip addr add "${LOCAL_ADDRESS}/${NWMASK}" dev "${DEVICE}" ip link set "${DEVICE}" up sleep 2 ip link add vxlan1 type vxlan id 42 \ remote "${REMOTE_ADDRESS}" \ local "${LOCAL_ADDRESS}" \ dstport 0 \ dev "${DEVICE}" ip addr add fc00::1/64 dev vxlan1 ip link set vxlan1 up sleep 2 rm -f vxlan.pcap echo "Running tcpdump and iperf3..." ( nohup tcpdump -i any -w vxlan.pcap >/dev/null 2>&1 ) & sleep 2 iperf3 -c fc00::2 >/dev/null pkill tcpdump echo echo -n "Max. Paket Size: " tcpdump -r vxlan.pcap -nnle 2>/dev/null \ | grep "${LOCAL_ADDRESS}.*> ${REMOTE_ADDRESS}.*OTV" \ | awk '{print $8}' | awk -F ':' '{print $1}' \ | sort -n | tail -1 echo ip link del vxlan1 ip addr del ${LOCAL_ADDRESS}/${NWMASK} dev "${DEVICE}" === SNAP === The expected outcome is Max. Paket Size: 64904 This is what you see on igb, the code igc has been taken from. However, on igc the output is Max. Paket Size: 1516 so the GSO aggregate packets are segmented by the kernel before calling igc_xmit_frame. Inside the subsequent call to igc_tso, the check for skb_is_gso(skb) fails and the function returns prematurely. It turns out that this occurs because the feature flags aren't set entirely correctly in igc_probe. In contrast to the original code from igb_probe, igc_probe neglects to set the flags required to allow tunnel offloading. Setting the same flags as igb fixes the issue on igc. Fixes: 34428dff3679 ("igc: Add GSO partial support") Signed-off-by: Paolo Abeni <pabeni@xxxxxxxxxx> Tested-by: Corinna Vinschen <vinschen@xxxxxxxxxx> Acked-by: Sasha Neftin <sasha.neftin@xxxxxxxxx> Tested-by: Nechama Kraus <nechamax.kraus@xxxxxxxxxxxxxxx> Signed-off-by: Tony Nguyen <anthony.l.nguyen@xxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/net/ethernet/intel/igc/igc_main.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) --- a/drivers/net/ethernet/intel/igc/igc_main.c +++ b/drivers/net/ethernet/intel/igc/igc_main.c @@ -5962,7 +5962,9 @@ static int igc_probe(struct pci_dev *pde if (pci_using_dac) netdev->features |= NETIF_F_HIGHDMA; - netdev->vlan_features |= netdev->features; + netdev->vlan_features |= netdev->features | NETIF_F_TSO_MANGLEID; + netdev->mpls_features |= NETIF_F_HW_CSUM; + netdev->hw_enc_features |= netdev->vlan_features; /* MTU range: 68 - 9216 */ netdev->min_mtu = ETH_MIN_MTU;