Re: [Qemu-devel] [PATCH 4/5] net/dump: Add dump option for netdev devices

[Thomas Huth <thuth@redhat.com>]

On Fri, 03 Jul 2015 13:28:45 +0200
Markus Armbruster <armbru@redhat.com> wrote:

> Thomas Huth <thuth@redhat.com> writes:
> 
> > So far it is not possible to dump network traffic with the "-netdev"
> > option yet - this is only possible with the "-net" option and an
> > internal "hub".
> > This patch now fixes this ugliness by adding a proper, generic
> > dumpfile parameter to the "-netdev" option.
> >
> > Signed-off-by: Thomas Huth <thuth@redhat.com>
> > ---
> >  include/net/net.h |  1 +
> >  net/net.c         | 48 ++++++++++++++++++++++++++++++++++++++++++++++++
> >  qapi-schema.json  | 12 ++++++++++--
> >  3 files changed, 59 insertions(+), 2 deletions(-)
> >
> > diff --git a/include/net/net.h b/include/net/net.h
> > index b265047..62abc98 100644
> > --- a/include/net/net.h
> > +++ b/include/net/net.h
...
> > @@ -877,6 +889,36 @@ static int net_init_nic(const NetClientOptions *opts, const char *name,
> >      return idx;
> >  }
> >  
> > +static int netdev_init_dumpfile(const Netdev *netdev, const char *name,
> > +                                Error **errp)
> > +{
> > +    NetClientState *nc;
> > +    int dumplen = 65536;
> > +    int rc;
> > +
> > +    if (netdev->opts->kind == NET_CLIENT_OPTIONS_KIND_TAP
> > +        && netdev->opts->tap->has_vhost && netdev->opts->tap->vhost) {
> > +        error_setg(errp, "dumping does not work with vhost enabled");
> > +        return -1;
> > +    }
> > +
> > +    if (netdev->has_dumplen) {
> > +        dumplen = netdev->dumplen;
> 
> I keep reading "dumpling" for some reason... %-)

Were you hungry while reading the patch? :-)

> > +    }
> > +
> > +    nc = qemu_find_netdev(name);
> > +    if (!nc) {
> > +        error_setg(errp, "failed to lookup netdev for dump");
> > +        return -1;
> 
> Can this happen?
> 
> Hmm, see below.
...
> net_client_init_fun() creates a netdev with this name.  Since it doesn't
> return it, we have to look it up with qemu_find_netdev().  So the answer
> to "can this happen?" appears to be no.  assert(!rc)?

I agree, an assert() should be enough here!

 Thomas