Re: regression with forward proxy due to Revision 1912459

On Mon, May 19, 2025 at 7:42 PM Yann Ylavic <[email protected]> wrote:
>
> On Mon, May 19, 2025 at 5:47 PM Ruediger Pluem <[email protected]> wrote:
> >
> > On 5/19/25 5:27 PM, Yann Ylavic wrote:
> > > On Mon, May 19, 2025 at 4:54 PM Stefan Eissing via dev
> > > <[email protected]> wrote:
> > >>
> > >>> Am 19.05.2025 um 16:46 schrieb Yann Ylavic <[email protected]>:
> > >>>
> > >>>
> > >>> Hm, r1912459 added this test to disable reuse for CONNECT connections
> > >>> to ProxyRemote, because I thought that CONNECT requests were not
> > >>> reusable.
> > >>
> > >> Hmm, what kind of CONNECT connections are reusable? The common use case is a TLS tunnel, I think. It would not work to reuse that.
> > >
> > > I mean reusing the same TLS tunnel created with the target host
> > > through the RemoteProxy, pushing more data/requests to it as they
> > > come.
> > > I think it's no different than reusing a TLS connection to some direct
> > > backend, the same SSL* is used until it's shut down / closed (e.g.
> > > forward_info mismatch).
> >
> > Maybe I am lost now, but when the client uses us as a forward proxy and does a CONNECT to us the CONNECT to a remote proxy cannot
> > be used any longer once the client shuts down the connection to us.
>
> Yes but this is a case handled by mod_proxy_connect and there is no
> way that connections created by mod_proxy_connect are reused, they
> never go in the reslist, not using ap_proxy_determine_connection() or
> ap_proxy_release_connection().
>
> > It could work fine if the client uses a different HTTP method that requires us to do a CONNECT to the remote proxy. In this case
> > we could reuse the connection provided that host and port fit.
>
> This is the ap_proxy_determine_connection() case, where the origin
> server is to be connected through a ProxyRemote.
> This happens in reverse proxy configurations too, and in this case
> reusing the tunnel is useful because the target host/port is always
> the same (I think Jean Frederic is having a use case like this given
> the performance regression).
> For a forward proxy configuration I don't think keeping the tunnel
> alive is useful since the next request is likely for some other
> target, maybe we should not reuse ProxyRemote connections for this
> case only?

Actually connections attached to the "proxy:forward" worker are never
recycled so this last point is moot.
So I think we should be good by keeping conn->forward connections
alive (if not closed by other means) when the existing forward_info
still matches?

>
> Regards;
> Yann.