Re: [PATCH net-next v9 7/8] hsr: Move struct hsr_ethhdr to a global header

[Sebastian Andrzej Siewior <bigeasy@linutronix.de>]

On 2026-10-16 11:38:53 [+0200], Daniel Machon wrote:
> > In the offloading case the network driver needs to inspect the HSR
> > header to find out if the encapsulated type is a PTP packet where it
> > needs suppress offloading of the packet.
> > 
> > Move the header so it can be included the driver.
> 
> nits:
> 
> s/needs suppress/needs to suppress/
> s/included the driver/included by the driver/
> 
> This is the header that drivers needs to poke into, to find out if they should
> steer the frame and add a header or not, right? Would it make sense to add a few
> helpers here?

This is correct. Could we talk about the helper once we have the first
driver using them so there is an idea how a helper could look like?

In icssg, for PRP I have just
	"eth_hdr(skb)->h_proto != htons(ETH_P_1588"

as a check among a handful driver internal checks to figure out if
offloading here applies (so no header, no sending on both ports).
For HSR I have this:

|                       /*
|                        * On HSR:
|                        * - all packets except HSR including PTP get a
|                        *   header added
|                        * - HSR including a PTP frame or PTP frames are not
|                        *   sent on both ports, everything else is.
|                        */
|                       is_P_1588 = skb->protocol == htons(ETH_P_1588);
|                       is_P_HSR = skb->protocol == htons(ETH_P_HSR);
|                       if (is_P_HSR) {
|                               struct hsr_ethhdr *hsr_hdr;
|
|                               hsr_hdr = (struct hsr_ethhdr *)skb_mac_header(skb);
|                               if (hsr_hdr->hsr_tag.encap_proto == htons(ETH_P_1588))
|                                       inner_is_P_1588 = true;
|                       }

so it could get this logic and have is_P_1588 + is_P_HSR as returned/
set arguments in the driver logic, that follows.

> /Daniel

Sebastian