On Fri, 26 Jun 2015 10:44:59 +0100 Stefan Hajnoczi <stefa...@gmail.com> wrote:
> On Wed, Jun 24, 2015 at 05:56:20PM +0200, Thomas Huth wrote:
> > diff --git a/net/net.c b/net/net.c
> > index cc36c7b..8871b77 100644
> > --- a/net/net.c
> > +++ b/net/net.c
> > @@ -568,6 +568,12 @@ ssize_t qemu_deliver_packet(NetClientState *sender,
> > return 0;
> > }
> >
> > + if (nc->netdev_dump_enabled) {
> > + net_dump_receive(nc, data, size);
> > + } else if (sender->netdev_dump_enabled) {
> > + net_dump_receive(sender, data, size);
> > + }
...
> Perhaps dumping should happen after ->receive() has returned size. If
> ->receive() returns -1 the packet is discarded, and if it returns 0 the
> packet is queued (not delivered yet).
>
> If you dump unconditionally before ->receive() you will see queued
> packets dumped multiple times (each time the queue gets flushed).
I've now tried this, but then I suddenly get the packets in the wrong
order in the dump file (when using slirp networking), e.g.:
1 0.000000 10.0.2.2 -> 255.255.255.255 DHCP 590 DHCP Offer
2 0.000012 0.0.0.0 -> 255.255.255.255 DHCP 342 DHCP Discover
instead of:
1 0.000000 0.0.0.0 -> 255.255.255.255 DHCP 342 DHCP Discover
2 0.000035 10.0.2.2 -> 255.255.255.255 DHCP 590 DHCP Offer
Looks like with slirp, the answer is already sent before the initial
receive() function returns?
Any idea how to avoid that issue? If not, I think I'll simply keep the
dump hooks before calling the receive functions.
Thomas
pgpo2YC9SdJvd.pgp
Description: OpenPGP digital signature
