| Message ID | 20210614111322.26914-1-boris.sukholitko@broadcom.com |
|---|---|
| State | Superseded |
| Headers | show |
| Series | [net-next] net/sched: cls_flower: Remove match on n_proto | expand |
Hello: This patch was applied to netdev/net-next.git (refs/heads/master): On Mon, 14 Jun 2021 14:13:22 +0300 you wrote: > The following flower filters fail to match packets: > > tc filter add dev eth0 ingress protocol 0x8864 flower \ > action simple sdata hi64 > tc filter add dev eth0 ingress protocol 802.1q flower \ > vlan_ethtype 0x8864 action simple sdata "hi vlan" > > [...] Here is the summary with links: - [net-next] net/sched: cls_flower: Remove match on n_proto https://git.kernel.org/netdev/net-next/c/0dca2c7404a9 You are awesome, thank you! -- Deet-doot-dot, I am a bot. https://korg.docs.kernel.org/patchwork/pwbot.html
diff --git a/net/sched/cls_flower.c b/net/sched/cls_flower.c index d7869a984881..2e704c7a105a 100644 --- a/net/sched/cls_flower.c +++ b/net/sched/cls_flower.c @@ -1531,14 +1531,13 @@ static int fl_set_key(struct net *net, struct nlattr **tb, &mask->basic.n_proto, TCA_FLOWER_UNSPEC, sizeof(key->basic.n_proto)); + mask->basic.n_proto = cpu_to_be16(0); } else { key->basic.n_proto = ethertype; - mask->basic.n_proto = cpu_to_be16(~0); } } } else { key->basic.n_proto = ethertype; - mask->basic.n_proto = cpu_to_be16(~0); } }
The following flower filters fail to match packets: tc filter add dev eth0 ingress protocol 0x8864 flower \ action simple sdata hi64 tc filter add dev eth0 ingress protocol 802.1q flower \ vlan_ethtype 0x8864 action simple sdata "hi vlan" The protocol 0x8864 (ETH_P_PPP_SES) is a tunnel protocol. As such, it is being dissected by __skb_flow_dissect and it's internal protocol is being set as key->basic.n_proto. IOW, the existence of ETH_P_PPP_SES tunnel is transparent to the callers of __skb_flow_dissect. OTOH, in the filters above, cls_flower configures its key->basic.n_proto to the ETH_P_PPP_SES value configured by the user. Matching on this key fails because of __skb_flow_dissect "transparency" mentioned above. In the following, I would argue that the problem lies with cls_flower, unnessary attempting key->basic.n_proto match. There are 3 close places in fl_set_key in cls_flower setting up mask->basic.n_proto. They are (in reverse order of appearance in the code) due to: (a) No vlan is given: use TCA_FLOWER_KEY_ETH_TYPE parameter (b) One vlan tag is given: use TCA_FLOWER_KEY_VLAN_ETH_TYPE (c) Two vlans are given: use TCA_FLOWER_KEY_CVLAN_ETH_TYPE The match in case (a) is unneeded because flower has no its own eth_type parameter. It was removed by Jamal Hadi Salim in commit 488b41d020fb06428b90289f70a41210718f52b7 in iproute2. For TCA_FLOWER_KEY_ETH_TYPE the userspace uses the generic tc filter protocol field. Therefore the match for the case (a) is done by tc itself. The matches in cases (b), (c) are unneeded because the protocol will appear in and will be matched by flow_dissector_key_vlan.vlan_tpid. Therefore in the best case, key->basic.n_proto will try to repeat vlan key match again. The below patch removes mask->basic.n_proto setting and resets it to 0 in case (c). Signed-off-by: Boris Sukholitko <boris.sukholitko@broadcom.com> --- net/sched/cls_flower.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)