Messages in this thread | | | Date | Tue, 21 Apr 2020 08:28:10 +0200 | From | Steffen Klassert <> | Subject | Re: [PATCH net-next] xfrm: policy: Remove obsolete WARN while xfrm policy inserting |
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On Fri, Apr 17, 2020 at 07:01:52PM +0800, Yuehaibing wrote: > On 2020/4/15 15:14, Steffen Klassert wrote: > > On Thu, Apr 09, 2020 at 04:19:37PM +0800, Yuehaibing wrote: > >> > >> > >> On 2020/4/6 17:03, Steffen Klassert wrote: > >>> On Mon, Mar 30, 2020 at 10:05:32PM +0800, Yuehaibing wrote: > >>>> On 2020/3/28 19:23, Steffen Klassert wrote: > >>>>> On Fri, Mar 27, 2020 at 08:34:43PM +0800, YueHaibing wrote: > >>>>>> Since commit 7cb8a93968e3 ("xfrm: Allow inserting policies with matching > >>>>>> mark and different priorities"), we allow duplicate policies with > >>>>>> different priority, this WARN is not needed any more. > >>>>> > >>>>> Can you please describe a bit more detailed why this warning > >>>>> can't trigger anymore? > >>>> > >>>> No, this warning is triggered while detect a duplicate entry in the policy list > >>>> > >>>> regardless of the priority. If we insert policy like this: > >>>> > >>>> policy A (mark.v = 3475289, mark.m = 0, priority = 1) //A is inserted > >>>> policy B (mark.v = 0, mark.m = 0, priority = 0) //B is inserted > >>>> policy C (mark.v = 3475289, mark.m = 0, priority = 0) //C is inserted and B is deleted > >>> > >>> The codepath that replaces a policy by another should just trigger > >>> on policy updates (XFRM_MSG_UPDPOLICY). Is that the case in your > >>> test? > >> > >> Yes, this is triggered by XFRM_MSG_UPDPOLICY > >> > >>> > >>> It should not be possible to add policy C with XFRM_MSG_NEWPOLICY > >>> as long as you have policy B inserted. > >>> > >>> The update replaces an old policy by a new one, the lookup keys of > >>> the old policy must match the lookup keys of the new one. But policy > >>> B has not the same lookup keys as C, the mark is different. So B should > >>> not be replaced with C. > >> > >> 1436 static bool xfrm_policy_mark_match(struct xfrm_policy *policy, > >> 1437 struct xfrm_policy *pol) > >> 1438 { > >> 1439 u32 mark = policy->mark.v & policy->mark.m; > >> 1440 > >> 1441 if (policy->mark.v == pol->mark.v && policy->mark.m == pol->mark.m) > >> 1442 return true; > >> 1443 > >> 1444 if ((mark & pol->mark.m) == pol->mark.v && //policy is C, pol is B, so mark is 0, pol->mark.m is 0, pol->mark.v is 0 > >> 1445 policy->priority == pol->priority) //priority is same zero, so return true, B is replaced with C > >> 1446 return true; > >> 1447 > >> 1448 return false; > >> 1449 } > >> > >> Should xfrm_policy_mark_match be fixed? > > > > Yes, xfrm_policy_mark_match should only replace if the found > > policy has the same lookup keys. > > I'm wonder that lookup keys means association of mark.v and mark.m, or the mark (mark.v & mark.m).
Good point. I'd say the lookup lookup keys are identical if the policy lookup can't distinguish between the policies. So (mark.v & mark.m) should be it.
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