Kurt Kanzenbach <[email protected]> writes:
> On Wed Jul 29 2020, Russell King - ARM Linux admin wrote:
>> Would it make more sense to do:
>>
>> u8 *data = skb_mac_header(skb);
>> u8 *ptr = data;
>>
>> if (type & PTP_CLASS_VLAN)
>> ptr += VLAN_HLEN;
>>
>> switch (type & PTP_CLASS_PMASK) {
>> case PTP_CLASS_IPV4:
>> ptr += IPV4_HLEN(ptr) + UDP_HLEN;
>> break;
>>
>> case PTP_CLASS_IPV6:
>> ptr += IP6_HLEN + UDP_HLEN;
>> break;
>>
>> case PTP_CLASS_L2:
>> break;
>>
>> default:
>> return NULL;
>> }
>>
>> ptr += ETH_HLEN;
>>
>> if (ptr + 34 > skb->data + skb->len)
>> return NULL;
>>
>> return ptr;
>>
>> in other words, compare pointers, so that whether skb_push() etc has
>> been used on the skb is irrelevant?
I like this!
> The ptp v1 code always does locate the message type at
>
> msgtype = data + offset + OFF_PTP_CONTROL
>
> OFF_PTP_CONTROL is 32. However, looking at the ptp v1 header, the
> message type is located at offset 20. What am I missing here?
0x20 == 32? I see it at offset 32 in IEEE 1588.
