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

[Jason Wang]

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.

> +
>  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.

>      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.

> +    } 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.

> +
>      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)