Re: [Qemu-devel] [PATCH 0/3] slirp: deliver received TCP RSTs to the guest

[Samuel Thibault <samuel.thibault@gnu.org>]

Hello,

Thanks for this!

steven@steven676.net, on Tue 05 Apr 2016 17:13:58 -0700, wrote:
> The second,
> which fixes delivery of an RST interrupting an already-established TCP
> connection, was submitted by Edgar Iglesias in 2008 and appears to have
> been missed then.  The last patch fixes the case where the remote end
> sends RST in reply to our SYN (rejects our incoming connection attempt).

It seems I'm getting another crash with these: sowrite would be called
too for the reseted socket, while the socket has been freed and is not
even on the polling list any more, I had to additionally do the patch
below, could you review it so I can push the whole series?

> I've been unable to test the specific case it
> addresses (an established connection interrupted by RST),

It's actually quite easy: just reboot the server :) The new instance of
the server will send a RST whenever the client sends more data.

Samuel


diff --git a/slirp/slirp.c b/slirp/slirp.c
index fef526c..b13b9af 100644
--- a/slirp/slirp.c
+++ b/slirp/slirp.c
@@ -553,6 +553,11 @@ void slirp_pollfds_poll(GArray *pollfds, int select_error)
                     if (ret > 0) {
                         tcp_output(sototcpcb(so));
                     }
+                    if (ret < 0) {
+                        /* Socket error and thus removed, do not try to do
+                         * anything more with it.  */
+                        continue;
+                    }
                 }
 
                 /*