Re: [Qemu-devel] [PATCH COLO-Frame v14 31/40] net/filter: Add a 'status' property for filter object

[Hailiang Zhang]

Hi Jason,

Happy spring festival! ;)

On 2016/2/18 11:00, Jason Wang wrote:
> On 02/06/2016 05:28 PM, zhanghailiang wrote:
> > With this property, users can control if this filter is 'enable'
> > or 'disable'. The default behavior for filter is enabled.
> >
> > We will skip the disabled filter when delivering packets in net layer.
> >
> > Signed-off-by: zhanghailiang <address@hidden>
> > Cc: Jason Wang <address@hidden>
> > Cc: Yang Hongyang <address@hidden>
> > ---
> >   include/net/filter.h |  1 +
> >   net/filter.c         | 45 +++++++++++++++++++++++++++++++++++++++++++++
> >   2 files changed, 46 insertions(+)
> >
> > diff --git a/include/net/filter.h b/include/net/filter.h
> > index 5639976..af3c53c 100644
> > --- a/include/net/filter.h
> > +++ b/include/net/filter.h
> > @@ -55,6 +55,7 @@ struct NetFilterState {
> >       char *netdev_id;
> >       NetClientState *netdev;
> >       NetFilterDirection direction;
> > +    bool enabled;
> >       QTAILQ_ENTRY(NetFilterState) next;
> >   };
> >
> > diff --git a/net/filter.c b/net/filter.c
> > index d2a514e..5551cf1 100644
> > --- a/net/filter.c
> > +++ b/net/filter.c
> > @@ -17,6 +17,11 @@
> >   #include "qom/object_interfaces.h"
> >   #include "qemu/iov.h"
> >
> > +static inline bool qemu_need_skip_netfilter(NetFilterState *nf)
> > +{
> > +    return nf->enabled ? false : true;
> > +}
>
> Suggest to rename this to qemu_netfilter_can_skip.

OK, i will fix it.

> > +
> >   ssize_t qemu_netfilter_receive(NetFilterState *nf,
> >                                  NetFilterDirection direction,
> >                                  NetClientState *sender,
> > @@ -25,6 +30,10 @@ ssize_t qemu_netfilter_receive(NetFilterState *nf,
> >                                  int iovcnt,
> >                                  NetPacketSent *sent_cb)
> >   {
> > +    /* Don't go through the filter if it is disabled */
> > +    if (qemu_need_skip_netfilter(nf)) {
> > +        return 0;
> > +    }
>
> The code is self explained, so the commnet is useless.

OK, i will remove it.

> >       if (nf->direction == direction ||
> >           nf->direction == NET_FILTER_DIRECTION_ALL) {
> >           return NETFILTER_GET_CLASS(OBJECT(nf))->receive_iov(
> > @@ -134,8 +143,41 @@ static void netfilter_set_direction(Object *obj, int 
> > direction, Error **errp)
> >       nf->direction = direction;
> >   }
> >
> > +static char *netfilter_get_status(Object *obj, Error **errp)
> > +{
> > +    NetFilterState *nf = NETFILTER(obj);
> > +
> > +    if (nf->enabled) {
> > +        return g_strdup("enable");
> > +    } else {
> > +        return g_strdup("disable");
> > +    }
> > +}
> > +
> > +static void netfilter_set_status(Object *obj, const char *str, Error **errp)
> > +{
> > +    NetFilterState *nf = NETFILTER(obj);
> > +
> > +    if (!strcmp(str, "enable")) {
> > +        nf->enabled = true;
> > +    } else if (!strcmp(str, "disable")) {
> > +        nf->enabled = false;
>
> Do we need a filter specific callback here to drain filter's queue? E.g
> for filter-buffer ,need to release all the packets that has been buffered.

I don't think we need to do that here, we drain the filter's queue explicitly
when we try to change the filter's status .
Besides, it seems that, we didn't have a callback in filter layer to process
the queued packets for different types of filters.

> > +    } else {
> > +        error_setg(errp, "Invalid value for netfilter status, "
> > +                         "should be 'enable' or 'disable'");
> > +    }
> > +}
> > +
> >   static void netfilter_init(Object *obj)
> >   {
> > +    NetFilterState *nf = NETFILTER(obj);
> > +
> > +    /*
> > +    * If not configured with 'status' property, the default status
> > +    * for netfilter will be enabled.
> > +    */
> > +    nf->enabled = true;
>
> The code is clear too, so the comment need to be moved to qemu-options.hx.

OK, i will fix it in next version.

Thanks,
Hailiang

> > +
> >       object_property_add_str(obj, "netdev",
> >                               netfilter_get_netdev_id, netfilter_set_netdev_id,
> >                               NULL);
> > @@ -143,6 +185,9 @@ static void netfilter_init(Object *obj)
> >                                NetFilterDirection_lookup,
> >                                netfilter_get_direction, netfilter_set_direction,
> >                                NULL);
> > +    object_property_add_str(obj, "status",
> > +                            netfilter_get_status, netfilter_set_status,
> > +                            NULL);
> >   }
> >
> >   static void netfilter_complete(UserCreatable *uc, Error **errp)
>
>
> .