Re: [Qemu-devel] [PATCH COLO-Frame v11 34/39] net/filter-buffer: Add default filter-buffer for each netdev

[Wen Congyang]

On 11/24/2015 05:25 PM, zhanghailiang wrote:
> We add each netdev a default filter-buffer, which will be used for COLO
> or Micro-checkpoint to buffer VM's packets. The name of default filter-buffer
> is 'nop'.
> For the default filter-buffer, it will not buffer any packets in default.
> So it has no side effect for the netdev.

No, filter-buffer doesn't support vhost, so if you add default filter-buffer
for each netdev, you can't use vhost.

Thanks
Wen Congyang

> 
> Signed-off-by: zhanghailiang <address@hidden>
> Cc: Jason Wang <address@hidden>
> Cc: Yang Hongyang <address@hidden>
> ---
> v11:
> - New patch
> ---
>  include/net/filter.h |  3 +++
>  net/filter-buffer.c  | 74 
> ++++++++++++++++++++++++++++++++++++++++++++++++++++
>  net/net.c            |  8 ++++++
>  3 files changed, 85 insertions(+)
> 
> diff --git a/include/net/filter.h b/include/net/filter.h
> index 2deda36..01a7e90 100644
> --- a/include/net/filter.h
> +++ b/include/net/filter.h
> @@ -74,4 +74,7 @@ ssize_t qemu_netfilter_pass_to_next(NetClientState *sender,
>                                      int iovcnt,
>                                      void *opaque);
>  
> +void netdev_add_default_filter_buffer(const char *netdev_id,
> +                                      NetFilterDirection direction,
> +                                      Error **errp);
>  #endif /* QEMU_NET_FILTER_H */
> diff --git a/net/filter-buffer.c b/net/filter-buffer.c
> index 57be149..195af68 100644
> --- a/net/filter-buffer.c
> +++ b/net/filter-buffer.c
> @@ -14,6 +14,12 @@
>  #include "qapi/qmp/qerror.h"
>  #include "qapi-visit.h"
>  #include "qom/object.h"
> +#include "net/net.h"
> +#include "qapi/qmp/qdict.h"
> +#include "qapi/qmp-output-visitor.h"
> +#include "qapi/qmp-input-visitor.h"
> +#include "monitor/monitor.h"
> +#include "qmp-commands.h"
>  
>  #define TYPE_FILTER_BUFFER "filter-buffer"
>  
> @@ -26,6 +32,8 @@ typedef struct FilterBufferState {
>      NetQueue *incoming_queue;
>      uint32_t interval;
>      QEMUTimer release_timer;
> +    bool is_default;
> +    bool enable_buffer;
>  } FilterBufferState;
>  
>  static void filter_buffer_flush(NetFilterState *nf)
> @@ -65,6 +73,10 @@ static ssize_t filter_buffer_receive_iov(NetFilterState 
> *nf,
>  {
>      FilterBufferState *s = FILTER_BUFFER(nf);
>  
> +    /* Don't buffer any packets if the filter is not enabled */
> +    if (!s->enable_buffer) {
> +        return 0;
> +    }
>      /*
>       * We return size when buffer a packet, the sender will take it as
>       * a already sent packet, so sent_cb should not be called later.
> @@ -102,6 +114,7 @@ static void filter_buffer_cleanup(NetFilterState *nf)
>  static void filter_buffer_setup(NetFilterState *nf, Error **errp)
>  {
>      FilterBufferState *s = FILTER_BUFFER(nf);
> +    char *path = object_get_canonical_path_component(OBJECT(nf));
>  
>      /*
>       * We may want to accept zero interval when VM FT solutions like MC
> @@ -114,6 +127,7 @@ static void filter_buffer_setup(NetFilterState *nf, Error 
> **errp)
>      }
>  
>      s->incoming_queue = qemu_new_net_queue(qemu_netfilter_pass_to_next, nf);
> +    s->is_default = !strcmp(path, "nop");
>      if (s->interval) {
>          timer_init_us(&s->release_timer, QEMU_CLOCK_VIRTUAL,
>                        filter_buffer_release_timer, nf);
> @@ -163,6 +177,66 @@ out:
>      error_propagate(errp, local_err);
>  }
>  
> +/*
> +* This will be used by COLO or MC FT, for which they will need
> +* to buffer the packets of VM's net devices, Here we add a default
> +* buffer filter for each netdev. The name of default buffer filter is
> +* 'nop'
> +*/
> +void netdev_add_default_filter_buffer(const char *netdev_id,
> +                                      NetFilterDirection direction,
> +                                      Error **errp)
> +{
> +    QmpOutputVisitor *qov;
> +    QmpInputVisitor *qiv;
> +    Visitor *ov, *iv;
> +    QObject *obj = NULL;
> +    QDict *qdict;
> +    void *dummy = NULL;
> +    const char *id = "nop";
> +    char *queue = g_strdup(NetFilterDirection_lookup[direction]);
> +    NetClientState *nc = qemu_find_netdev(netdev_id);
> +    Error *err = NULL;
> +
> +    /* FIXME: Not support multiple queues */
> +    if (!nc || nc->queue_index > 1) {
> +        return;
> +    }
> +    qov = qmp_output_visitor_new();
> +    ov = qmp_output_get_visitor(qov);
> +    visit_start_struct(ov,  &dummy, NULL, NULL, 0, &err);
> +    if (err) {
> +        goto out;
> +    }
> +    visit_type_str(ov, &nc->name, "netdev", &err);
> +    if (err) {
> +        goto out;
> +    }
> +    visit_type_str(ov, &queue, "queue", &err);
> +    if (err) {
> +        goto out;
> +    }
> +    visit_end_struct(ov, &err);
> +    if (err) {
> +        goto out;
> +    }
> +    obj = qmp_output_get_qobject(qov);
> +    g_assert(obj != NULL);
> +    qdict = qobject_to_qdict(obj);
> +    qmp_output_visitor_cleanup(qov);
> +
> +    qiv = qmp_input_visitor_new(obj);
> +    iv = qmp_input_get_visitor(qiv);
> +    object_add(TYPE_FILTER_BUFFER, id, qdict, iv, &err);
> +    qmp_input_visitor_cleanup(qiv);
> +    qobject_decref(obj);
> +out:
> +    g_free(queue);
> +    if (err) {
> +        error_propagate(errp, err);
> +    }
> +}
> +
>  static void filter_buffer_init(Object *obj)
>  {
>      object_property_add(obj, "interval", "int",
> diff --git a/net/net.c b/net/net.c
> index ade6051..b36d49f 100644
> --- a/net/net.c
> +++ b/net/net.c
> @@ -1028,6 +1028,14 @@ static int net_client_init1(const void *object, int 
> is_netdev, Error **errp)
>          }
>          return -1;
>      }
> +
> +    if (is_netdev) {
> +        const Netdev *netdev = object;
> +
> +        netdev_add_default_filter_buffer(netdev->id,
> +                                         NET_FILTER_DIRECTION_RX,
> +                                         errp);
> +    }
>      return 0;
>  }
>  
>