[U-Boot] [PATCH] TCP and wget implementation. Ptch V5 1 of 3

[Heinrich Schuchardt]

On 01/29/2018 06:30 PM, Duncan Hare wrote:
>> The patch is trying to put everything into net.c. This is a mess and
>> not where we should head to.
> 
> Not at all. I tried that and it was correctly rejected. The TCP
> functions are in tcp.c, and the wget functions in wget.c
> 
> There is no  socket. There is no socket analogue. There is no
> widespread correct re-ordering of packets, because in a kernel download 
> the relative address of each block is derived for the tcp sequence
> number, and the kernel image in memory itself is in the correct order,
> as defined by tcp sequence number.

You wouldn't implement a TCP protocol that cannot be reused to implement
other higher protocols?

TCP packets are not expected to arrive in sequence. And the length of
packets may vary. You need a buffer for a few packets to put them into
the right sequence again.

> 
>>
>> We should have have one driver per protocol.
>>
>> The IP driver should enumerate all drivers protocols like TCP and UDP
>> that want to listen to it using a Linux list. This way we get rid of
>> all those needless #ifdef CONFIGs. Using the list the IP driver will
>> hand out packets to the respective higher protocol driver.
> 
> The choice was to make minimal changes to the
> current net.c, in consultation with other in the u-boot realm.
> 
>>
>> A separate driver shall implement the TCP protocol and provide methods
>> to open a socket, to read and write to the socket and to close the
>> socket.
>>
> "shall"? Please do not use the imperative, unless you are approaching
> me with money.
> 
>> Next we want a driver for the HTTP protocol. It should have function
>> to open a connection, to send a request, to receive a response, and to
>> close the connection. If this driver is requested to open a connection
>> it shall call the TCP driver to open a socket. It will then receive
>> all packets from the relevant IP address on the relevant port until it
>> closes the socket.
>>
> The http protocol is very simple, and consists of a TCP connection and a
> header, both for request and response.

For first use implementing GET is sufficient. But the structure of the
driver should allow to easily add POST and CONNECT.

> 
>> The wget command should be in a separate file. It will call the
>> appropriate functions of the HTTP driver to open a connection, post
>> the request, receive the response, and finally close the connection.
> 
> It is and it does. It also include the http headers, bec‭ause of their
> simplicity.
> 
>>
>> The work should start with refactoring the existing coding into
>> separate drivers for the existing protocols. When that is completed
>> you can start adding TCP relevant code.
> 
> Will you pay for that work?

The only thing that needs to be factored out of net.c is the IP protocol.

>  
>> Please, do not send single patches but complete patch series.
> 
> I do the best I can with my limited knowledge of the tools. I have sent
> a series. My understand of both git and patman is limited.

This is how I send a patch series:

git format-patch HEAD~5 -ns --cover-letter --subject-prefix='PATCH v5'

Edit the cover letter.
Add in each patch after the first --- the changes relative to the prior
version of the patch. Add another ---.

Put only these files into a directory (let's assume it is named 'patches').

git send-email \
--from="author <author at example.com>" \
--to="maintainer <mantainer at example.com" \
--cc="interested <interested at example.com>" \
--cc=u-boot at lists.denx.de \
patches\*

Best regards

Heinrich

> 
>>
>> Best regards
>>
>> Heinrich
> 
> 
> 
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