Fri, Sep 29, 2017 at 07:59:35PM CEST, t...@herbertland.com wrote: >On Fri, Sep 29, 2017 at 10:42 AM, David Miller <da...@davemloft.net> wrote: >> From: Tom Herbert <t...@herbertland.com> >> Date: Fri, 29 Sep 2017 08:48:55 -0700 >> >>> The flow_dissector interface is not a uAPI. >> >> That's not true, insofar as cls_flower.c uses the flow_dissector >> therefore if you change the flow_dissector in certain ways then >> cls_flower.c might have it's behavior changed and that is in fact UAPI >> facing. > >Then I would suggest adding another flag like FLOW_DISSECTOR_F_FLOWER >and when anyone puts new code into flow_dissector they can wrap it >with "if !(flags & FLOW_DISSECTOR_F_FLOWER)". If the flower uAPI is >subsequently update then the conditional can be removed. This way >flower can support maintain its APIs, but we can still still extend >and improve flow_dissector for othersuse cases.
This is not flower-specific problem. Flow_dissector is a servant of many. As such, it is instructed what should it do. If you want to change the way inner headers are parsed, you should either: 1) change the callers so they are behaving the same as before 2) make the flow_dissection change optional so the caller can say if he wants original or new behaviour.
