[Intel-wired-lan] [PATCH] igc: fix tunnel offloading

[Sasha Neftin <sasha.neftin@intel.com>]

On 8/17/2021 16:42, Sasha Neftin wrote:
> On 8/17/2021 16:16, Corinna Vinschen wrote:
>> From: Paolo Abeni <pabeni@redhat.com>
>>
>> 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.
>>
>> Signed-off-by: Paolo Abeni <pabeni@redhat.com>
>> Tested-by: Corinna Vinschen <vinschen@redhat.com>
>> ---
>> ? drivers/net/ethernet/intel/igc/igc_main.c | 4 +++-
>> ? 1 file changed, 3 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/net/ethernet/intel/igc/igc_main.c 
>> b/drivers/net/ethernet/intel/igc/igc_main.c
>> index b7aab35c1132..79efb3e6a03e 100644
>> --- a/drivers/net/ethernet/intel/igc/igc_main.c
>> +++ b/drivers/net/ethernet/intel/igc/igc_main.c
>> @@ -6264,7 +6264,9 @@ static int igc_probe(struct pci_dev *pdev,
>> ????? 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;
>Acked-by: Sasha Neftin <sasha.neftin@intel.com>