Re: [PATCH net v2 1/1] net: stmmac: Prevent DSA tags from breaking COE on stmmac

On Wed, Jan 3, 2024 at 9:10 PM Vladimir Oltean olteanv@gmail.com wrote:

On Tue, Jan 02, 2024 at 05:27:15PM +0100, Romain Gantois wrote:

...

+/* Check if ethertype will trigger IP

• • header checks/COE in hardware
• */

+static inline bool stmmac_has_ip_ethertype(struct sk_buff *skb) +{

• __be16 proto = eth_header_parse_protocol(skb);
  

• return (proto == htons(ETH_P_IP)) || (proto == htons(ETH_P_IPV6)) ||
  

•         (proto == htons(ETH_P_8021Q));
  

proto == htons(ETH_P_8021Q) means that the skb has an IP EtherType? What if an IP header does not follow after the VLAN header?

It's probably best to do like I do here: https://lore.kernel.org/netdev/20240102-new-gemini-ethernet-regression-v5-2-...

+ if (ethertype == ETH_P_8021Q) + ethertype = ntohs(__vlan_get_protocol(skb, htons(ethertype), NULL));

Yours, Linus Walleij