Re: [Qemu-devel] [PATCH V4 02/12] net/filter-mirror.c: Add new option to enable vnet support for filter-mirror

[Zhang Chen]

On 05/13/2017 09:49 AM, Hailiang Zhang wrote:
> Hi,
>
> On 2017/5/12 9:41, Zhang Chen wrote:
> > We add the vnet_hdr option for filter-mirror, default is disable.
> > If you use virtio-net-pci net driver, please enable it.
> > You can use it for example:
> > -object 
> > filter-mirror,id=m0,netdev=hn0,queue=tx,outdev=mirror0,vnet_hdr=on
>
> Is there any way to detect whether or not the vNIC using vnet_hdr ?

Yes, we can. but we can't ensure the backward compatibility.
Detail:
https://lists.nongnu.org/archive/html/qemu-devel/2017-05/msg01959.html

> I don't think it is a good idea to let users to confirm it, especially 
> for users who may not
> be so familiar with the vNIC realizing in qemu.

If you don't use virtio-net-pci that you need't add this option, default 
is false.

Thanks
Zhang Chen

> Thanks,
> Hailiang
>
> > Signed-off-by: Zhang Chen <address@hidden>
> > ---
> >   net/filter-mirror.c | 34 ++++++++++++++++++++++++++++++++++
> >   qemu-options.hx     |  5 +++--
> >   2 files changed, 37 insertions(+), 2 deletions(-)
> >
> > diff --git a/net/filter-mirror.c b/net/filter-mirror.c
> > index 72fa7c2..3766414 100644
> > --- a/net/filter-mirror.c
> > +++ b/net/filter-mirror.c
> > @@ -38,6 +38,7 @@ typedef struct MirrorState {
> >       NetFilterState parent_obj;
> >       char *indev;
> >       char *outdev;
> > +    bool vnet_hdr;
> >       CharBackend chr_in;
> >       CharBackend chr_out;
> >       SocketReadState rs;
> > @@ -308,6 +309,13 @@ static char *filter_mirror_get_outdev(Object 
> > *obj, Error **errp)
> >       return g_strdup(s->outdev);
> >   }
> >   +static char *filter_mirror_get_vnet_hdr(Object *obj, Error **errp)
> > +{
> > +    MirrorState *s = FILTER_MIRROR(obj);
> > +
> > +    return s->vnet_hdr ? g_strdup("on") : g_strdup("off");
> > +}
> > +
> >   static void
> >   filter_mirror_set_outdev(Object *obj, const char *value, Error **errp)
> >   {
> > @@ -322,6 +330,21 @@ filter_mirror_set_outdev(Object *obj, const char 
> > *value, Error **errp)
> >       }
> >   }
> >   +static void filter_mirror_set_vnet_hdr(Object *obj,
> > +                                       const char *value,
> > +                                       Error **errp)
> > +{
> > +    MirrorState *s = FILTER_MIRROR(obj);
> > +
> > +    if (strcmp(value, "on") && strcmp(value, "off")) {
> > +        error_setg(errp, "Invalid value for filter-mirror vnet_hdr, "
> > +                         "should be 'on' or 'off'");
> > +        return;
> > +    }
> > +
> > +    s->vnet_hdr = !strcmp(value, "on");
> > +}
> > +
> >   static char *filter_redirector_get_outdev(Object *obj, Error **errp)
> >   {
> >       MirrorState *s = FILTER_REDIRECTOR(obj);
> > @@ -340,8 +363,19 @@ filter_redirector_set_outdev(Object *obj, const 
> > char *value, Error **errp)
> >     static void filter_mirror_init(Object *obj)
> >   {
> > +    MirrorState *s = FILTER_MIRROR(obj);
> > +
> >       object_property_add_str(obj, "outdev", filter_mirror_get_outdev,
> >                               filter_mirror_set_outdev, NULL);
> > +
> > +    /*
> > +     * The vnet_hdr is disabled by default, if you want to enable
> > +     * this option, you must enable all the option on related modules
> > +     * (like other filter or colo-compare).
> > +     */
> > +    s->vnet_hdr = false;
> > +    object_property_add_str(obj, "vnet_hdr", 
> > filter_mirror_get_vnet_hdr,
> > +                             filter_mirror_set_vnet_hdr, NULL);
> >   }
> >     static void filter_redirector_init(Object *obj)
> > diff --git a/qemu-options.hx b/qemu-options.hx
> > index 70c0ded..1e08481 100644
> > --- a/qemu-options.hx
> > +++ b/qemu-options.hx
> > @@ -4024,10 +4024,11 @@ queue @var{all|rx|tx} is an option that can 
> > be applied to any netfilter.
> >   @option{tx}: the filter is attached to the transmit queue of the 
> > netdev,
> >                where it will receive packets sent by the netdev.
> >   address@hidden -object 
> > filter-mirror,address@hidden,address@hidden,address@hidden,address@hidden|rx|tx}]
> > address@hidden -object 
> > filter-mirror,address@hidden,address@hidden,address@hidden,address@hidden|off}[,address@hidden|rx|tx}]
> >     filter-mirror on netdev @var{netdevid},mirror net packet to chardev
> > address@hidden
> > address@hidden, if vnet_hdr = on, filter-mirror will mirror packet
> > +with vnet_hdr_len.
> >     @item -object 
> > filter-redirector,address@hidden,address@hidden,address@hidden,
> >   address@hidden,address@hidden|rx|tx}]
>
>
>
>
> .

--
Thanks
Zhang Chen