Re: (OS 10048)Only one usage of each socket address (protocol/network address/port) is normally permitted

On Wed, Feb 12, 2025 at 12:07 PM Yann Ylavic <[email protected]> wrote:
>
> On Wed, Feb 12, 2025 at 11:16 AM jean-frederic clere <[email protected]> wrote:
> >
> > According to my tests for some reasons ap_proxy_release_connection() now
> > does an apr_pool_clear() and was doing a connection_cleanup() before 2.4.58.
>
> What does your ProxyPass/ProxyPassMatch look like?
> AFAICT connection_cleanup() closes the connection by clearing its pool
> only if !worker->s->is_address_reusable ([1]), meaning disablereuse=on
> or enablereuse=off was set ([2]), or the ProxyPassMatch contains a
> $-substitution in the hostname[:port] part of the URL ([3]).
>
> [1] https://github.com/apache/httpd/blob/2.4.63/modules/proxy/proxy_util.c#L1657-L1661
> [2] https://github.com/apache/httpd/blob/2.4.63/modules/proxy/proxy_util.c#L2270-L2273
> [3] https://github.com/apache/httpd/blob/2.4.63/modules/proxy/proxy_util.c#L1989-L2034

Oh, and there is also this ProxyPassMatch case ([4]) where we force
disablereuse for compatibility with < 2.4.47 which never reused
connections.
So if there is a $-substitution *anywhere* in the worker URL then
connection reuse is disabled by default, but it can still be enabled
explicitly with enablereuse=on.
However it seems that [4] will cause worker->s->is_address_reusable =
0 in [3] (i.e. disable DNS reuse altogether) which is not really
expected, and would explain why the pool is cleared in
connection_cleanup(). Though whether the pool is cleared
(!is_address_reusable) or the connection only is closed (disablereuse)
shouldn't make a difference for your issue, in both cases the socket
gets closed for each request..

[4] https://github.com/apache/httpd/blob/2.4.63/modules/proxy/proxy_util.c#L2140-L2159

>
> But it seems that mod_proxy_cluster is creating and initializing its
> own proxy workers, and I don't know which games it plays on its own
> with worker->s->disablereuse or worker->s->is_address_reusable or
> worker->s->is_address_reusable.
>
>
> Regards;
> Yann.