[Cake] openwrt build with latest cake and other qdiscs

[Sebastian Moeller]

Hi Jonathan,


On May 14, 2015, at 17:32 , Jonathan Morton <chromatix99 at gmail.com> wrote:

> 
>> On 14 May, 2015, at 17:57, Sebastian Moeller <moeller0 at gmx.de> wrote:
>> 
>> I am probably daft, but looking at the comment in front of skb_gso_network_seglen() (see http://lxr.free-electrons.com/ident?i=skb_gso_network_seglen ) makes me thick there is a way of getting the lengths of the individual segments of a GSO aggregate
> 
> All the segments (except possibly the last) will be MTU sized, I suspect.  The necessary headers would be duplicated, with fresh (sequential) IP IDs, adjusted TCP sequence numbers and recalculated checksums.  The size of the last segment (and maybe the number of segments) would depend on the header size, since a bigger header (due eg. to TCP timestamps) reduces the payload per packet.

	As I said, I am out of my league here ;), I would not be amazed if there was a way to get to the segment lengths without going to the data (as I believe the GSO header has all the information to pick the individual payloads out of the continuous GSO skb, but I lack the skill to find the correct reference)

> 
> I don’t immediately see how to reliably calculate the sizes of the resulting packets.  So I’d rather split them up and be certain about it, in the cases where it matters most, and take the size of the aggregate as sufficiently reliable in other cases.

	I guess your idea of peeling for ATM carrier and for >1ms wire time aggregates sounds like a decent idea…

Best Regards
	Sebastian

> 
> - Jonathan Morton
>