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

[Hailiang Zhang]

On 2015/12/3 9:17, Wen Congyang wrote:

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.

Have you tested it ? Did the default filter-buffer break vhost ?
It's not supposed to break vhost, I will look into it. Thanks.

Thanks
Wen Congyang

Signed-off-by: zhanghailiang <zhang.zhanghaili...@huawei.com>
Cc: Jason Wang <jasow...@redhat.com>
Cc: Yang Hongyang <hongyang.y...@easystack.cn>
---
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;
  }

.