netdev - Re: [PATCH net-next] tcp: change source port selection at bind() time

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Message-ID: <CANn89iJZ8RwFX-iy-2HkE=xD8gnsJ26BO5j=o0460yUt7HiYcA@mail.gmail.com>
Date: Mon, 19 Aug 2024 17:45:41 +0200
From: Eric Dumazet <edumazet@...gle.com>
To: Jason Xing <kerneljasonxing@...il.com>
Cc: davem@...emloft.net, kuba@...nel.org, pabeni@...hat.com, 
	dsahern@...nel.org, ncardwell@...gle.com, netdev@...r.kernel.org, 
	Jason Xing <kernelxing@...cent.com>
Subject: Re: [PATCH net-next] tcp: change source port selection at bind() time

On Fri, Aug 16, 2024 at 5:33 PM Jason Xing <kerneljasonxing@...il.com> wrote:
>
> From: Jason Xing <kernelxing@...cent.com>
>
> This is a follow-up patch to an eariler commit 207184853dbd ("tcp/dccp:
> change source port selection at connect() time").
>
> This patch extends the use of IP_LOCAL_PORT_RANGE option, so that we
> don't need to iterate every two ports which means only favouring odd
> number like the old days before 2016, which can be good for some
> users who want to keep in consistency with IP_LOCAL_PORT_RANGE in
> connect().

Except that bind() with a port reservation is not as common as a connect().
This is highly discouraged.

See IP_BIND_ADDRESS_NO_PORT

Can you provide a real use case ?

I really feel like you are trying to push patches 'just because you can'...

'The old days' before 2016 were not very nice, we had P0 all the time
because of port exhaustion.
Since 2016 and IP_BIND_ADDRESS_NO_PORT I no longer have war rooms stories.