Re: [Lksctp-developers] [RFC PATCH v2] Fast retransmit fixes

Re: [Lksctp-developers] [RFC PATCH v2] Fast retransmit fixes

[Wei Yongjun]

Hi Vlad:

This patch set cannot resolve Fast Recovery problem correctly.

Test Procedure:

Endpoint A                       Endpoint B
DATA (TSN = 1)  ------------->
DATA (TSN = 2)  -- (lost)---->
DATA (TSN = 3)  ---(lost)---->
DATA (TSN = 4)  ------------->
DATA (TSN = 5)  ------------->
                <-------------   SACK (CTSN = 1)
DATA (TSN = 6)  ------------->
                <-------------   SACK (CTSN = 1, GAP-START = 3, GAP-ENT = 3)
                <------------    SACK (CTSN = 1, GAP-START = 3, GAP-ENT = 4)
                <------------    SACK (CTSN = 1, GAP-START = 3, GAP-ENT = 5) 
DATA (TSN = 2)  -(fast rtx)-->
                <-------------   SACK (CTSN = 2, GAP-START = 2, GAP-ENT = 4)
DATA (TSN = 3)  -(can not do fast rtx)--

I am not sure is this a bug of your patch because I used this patchset 
manually. Can you check for this test?

Wei Yongjun


Vlad Yasevich wrote:
> This is an update to the Fast retransmit changes.
>
> This fixes a small bug introduced by a prior series where the fast_rtx
> hint in the outq structure was never cleared.
>
> All prior comments still stand.
>
>
>   

Re: [Lksctp-developers] [RFC PATCH v2] Fast retransmit fixes

[Vlad Yasevich]

Wei Yongjun wrote:
> Hi Vlad:
> 
> This patch set cannot resolve Fast Recovery problem correctly.
> 
> Test Procedure:
> 
> Endpoint A                       Endpoint B
> DATA (TSN = 1)  ------------->
> DATA (TSN = 2)  -- (lost)---->
> DATA (TSN = 3)  ---(lost)---->
> DATA (TSN = 4)  ------------->
> DATA (TSN = 5)  ------------->
>                <-------------   SACK (CTSN = 1)
> DATA (TSN = 6)  ------------->
>                <-------------   SACK (CTSN = 1, GAP-START = 3, GAP-ENT = 3)
>                <------------    SACK (CTSN = 1, GAP-START = 3, GAP-ENT = 4)
>                <------------    SACK (CTSN = 1, GAP-START = 3, GAP-ENT = 
> 5) DATA (TSN = 2)  -(fast rtx)-->
>                <-------------   SACK (CTSN = 2, GAP-START = 2, GAP-ENT = 4)
> DATA (TSN = 3)  -(can not do fast rtx)--
> 
> I am not sure is this a bug of your patch because I used this patchset 
> manually. Can you check for this test?
> 

Hi Wei

Yes,  I forgot to remove the call to sctp_list_dequeue() in sctp_outq_flush_rtx().
That's what was causing this error.

There was only one other small bug in the patch that I found with this scenario.  These
all stem from me attempting to break on 1 big patch into 3 smaller ones.

Anyway, I'll repost.

Thanks
-vlad