[PATCH v12 00/13] net: tcp: improve tcp support in legacy stack

[Mikhail Kshevetskiy]

On 05.11.2024 21:26, Tom Rini wrote:
> On Tue, Nov 05, 2024 at 09:07:17AM -0700, Simon Glass wrote:
>> Hi Tom,
>>
>> On Tue, 5 Nov 2024 at 08:47, Tom Rini <trini at konsulko.com> wrote:
>>> On Tue, Nov 05, 2024 at 08:15:25AM -0700, Simon Glass wrote:
>>>> Hi Peter,
>>>>
>>>> On Tue, 5 Nov 2024 at 06:10, Peter Robinson <pbrobinson at gmail.com> wrote:
>>>>> On Tue, 5 Nov 2024 at 13:03, Simon Glass <sjg at chromium.org> wrote:
>>>>>> Hi Tom,
>>>>>>
>>>>>> On Mon, 4 Nov 2024 at 16:32, Tom Rini <trini at konsulko.com> wrote:
>>>>>>> On Mon, Oct 28, 2024 at 05:31:30PM +0300, Mikhail Kshevetskiy wrote:
>>>>>>>
>>>>>>>> Legacy TCP stack is bad. Here are some of the known issues:
>>>>>>>>  * tcp packet from other connection can break a current one
>>>>>>>>  * tcp send sequence always starts from zero
>>>>>>>>  * bad tcp options processing
>>>>>>>>  * strange assumptions on packet size for selective acknowledge
>>>>>>>>  * tcp interface assumes one of the two scenarios:
>>>>>>>>      - data downloading from remote host to a board
>>>>>>>>      - request-response exchange with a small packets
>>>>>>>>    so it's not possible to upload large amount of data from the
>>>>>>>>    board to remote host.
>>>>>>>>  * wget test generate bad tcp stream, test should fail but it passes instead
>>>>>>>>
>>>>>>>> This series of patches fixes all of the above issues.
>>>>>>> I know Peter asked on the last one, but I want to ask as well. With lwIP
>>>>>>> merged, why do we want to add features to the old stack? I can see
>>>>>>> fixing issues, but not adding new functionality as well. Thanks.
>>>>>>>
>>>>>> Let's apply this. It has tests and the old stack is still used by a
>>>>>> lot of boards. At present lwip is only used on one. There is more work
>>>>>> to do on the new stack, including finishing off the sandbox
>>>>>> implementation.
>>>>> I agree with applying the fixes pieces, I do not agree with apply the
>>>>> HTTP server pieces. This series should actually be split into 3
>>>> But what is your objection?
>>>>
>>>> I would much rather just apply it ASAP. It has already gone through 12
>>>> versions, during which lwip has been prepared and applied.
>>> Yes, and to be blunt, the first bit of feedback I provided was "can you
>>> please look at the lwIP series instead?".
>>>
>>>> The HTTP server is a useful feature and we should be able to use it to
>>>> test networking in U-Boot in a more self-contained and performant
>>>> manner.
>>> I very much do not want to add more features to the legacy TCP stack.
>>> We're likely, long term, to still need some cut-back version of the old
>>> stack for the limited SPL cases.
>> This series has been in progress for a long time and it seems unfair
>> to just drop it, with one one board on the new stack.
> Well, I continue to not say that we should drop the series, but that we
> should take the fixes and not the new features. Because as far as I can
> tell, the current TCP stack is in such a shape that it's not
> production-usable anywhere and so the number of users argument is
> irrelevant.
>
I expected something like this when lwip was finally merged.
I was a bit surprised when Simon decide to merge this patch series.

At the moment we have no plans to update u-boot or backport lwip patches
to u-boot-2023.10.
So we will use our solution based on a legacy stack. I understand that
we should switch to lwip somewhere in the future. Unfortunately it's 
not a fast and easy process (update u-boot, rewrite http based firmware
upgrade, test new u-boot for several hardware configurations, test
customer devices migrations and so on).

Also we are limited in resources, so I am able to put my hands on u-boot
only from time to time.
So this is a long story.

Tom, Simon, Peter: what patches do you want to accept?

Mikhail Kshevetskiy