Messages in this thread | | | Date | Mon, 24 Aug 2009 15:54:28 +0800 | From | Wei Yongjun <> | Subject | Re: [PATCH] sctp: fix the check for path failure detection |
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Luo Chunbo 写道: > On Fri, 2009-08-21 at 17:47 -0400, Vlad Yasevich wrote: > >> Chunbo Luo wrote: >> >>> The transport is marked DOWN immediately after sending the max+1 HB, >>> which is equal to not sending the max+1 HB at all. We should wait >>> a next period and make sure the last HB is not acknowledged. >>> >>> >> I don't think this code does what you want either... >> >> Let's say path_max_rxt = 2. What we'll get is: >> timeout: >> err++ (1) >> if (err > 2) false >> send HB >> reset timer >> timeout: >> err++ (2) >> if (err > 2) false >> send HB >> reset timer >> timeout: >> err++ (3) >> if (err > 2) >> set transport DOWN >> send HB >> reset timer. >> >> We only had 2 unacknowledged HB when we should have had 3. >> > > The error count is increment after the HB was sent, and the error count > check is before sending HB. > > Let's say path_max_rxt =2 . What we really get is: > > timeout: > if( err > 2) false > send HB > err++ (1) > reset timer > timeout: > if( err > 2) false > send HB > err++ (2) > reset timer > timeout: > if( err > 2) false > send HB > err++ (3) > reset timer > timeout: > if( err > 2) > set transport DOWN > send HB > reset timer > > Here We had 3 unacknowledged HBs
But with Vlad's advice, you just need to do little change to the kernel codes, may be two lines's patch, and it can do the same thing.
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