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 <zhangchen.f...@cn.fujitsu.com>
---
  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.
  -@item -object 
filter-mirror,id=@var{id},netdev=@var{netdevid},outdev=@var{chardevid}[,queue=@var{all|rx|tx}]
+@item -object 
filter-mirror,id=@var{id},netdev=@var{netdevid},outdev=@var{chardevid},vnet_hdr=@var{on|off}[,queue=@var{all|rx|tx}]
    filter-mirror on netdev @var{netdevid},mirror net packet to chardev
-@var{chardevid}
+@var{chardevid}, if vnet_hdr = on, filter-mirror will mirror packet
+with vnet_hdr_len.
    @item -object 
filter-redirector,id=@var{id},netdev=@var{netdevid},indev=@var{chardevid},
  outdev=@var{chardevid}[,queue=@var{all|rx|tx}]




.


--
Thanks
Zhang Chen