【kernel-openEuler-22.03-LTS-SP1】net/sched: flower: fix parsing of ethertype following VLAN header

【标题描述】
A tc flower filter matching TCA_FLOWER_KEY_VLAN_ETH_TYPE is expected to
match the L2 ethertype following the first VLAN header, as confirmed by
linked discussion with the maintainer. However, such rule also matches
packets that have additional second VLAN header, even though filter has
both eth_type and vlan_ethtype set to "ipv4". Looking at the code this
seems to be mostly an artifact of the way flower uses flow dissector.
First, even though looking at the uAPI eth_type and vlan_ethtype appear
like a distinct fields, in flower they are all mapped to the same
key->basic.n_proto. Second, flow dissector skips following VLAN header as
no keys for FLOW_DISSECTOR_KEY_CVLAN are set and eventually assigns the
value of n_proto to last parsed header. With these, such filters ignore any
headers present between first VLAN header and first "non magic"
header (ipv4 in this case) that doesn't result
FLOW_DISSECT_RET_PROTO_AGAIN.

Fix the issue by extending flow dissector VLAN key structure with new
'vlan_eth_type' field that matches first ethertype following previously
parsed VLAN header. Modify flower classifier to set the new
flow_dissector_key_vlan->vlan_eth_type with value obtained from
TCA_FLOWER_KEY_VLAN_ETH_TYPE/TCA_FLOWER_KEY_CVLAN_ETH_TYPE uAPIs

【环境信息】
kernel-openEuler-22.03-LTS-SP1

【解决方案】

社区已经补丁解决此问题
commit 845f44ce3d9f13e45a1e4bedbe7c15a262568523

git cherry-pick -s 845f44ce3d9 （with linux-stable v5.10.186 repo added）
Reference:https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=linux-5.10.y&id=845f44ce3d9f13e45a1e4bedbe7c15a262568523

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