Re: [PATCH V4 1/3] net/filter: Remove vnet_hdr from filter-mirror and filter-redirector

[Jason Wang <jasowang@redhat.com>]

在 2021/10/27 上午2:17, Zhang Chen 写道:
> Make the vnet header a necessary part of filter transfer protocol.
> So remove the module's vnet_hdr_support switch here.
> It make other modules(like another filter-redirector,colo-compare...)
> know how to parse net packet correctly. If local device is not the
> virtio-net-pci, vnet_hdr_len will be 0.
>
> Signed-off-by: Zhang Chen <chen.zhang@intel.com>
> ---
>   net/filter-mirror.c | 88 ++++++++++-----------------------------------
>   qemu-options.hx     | 14 ++++----
>   2 files changed, 25 insertions(+), 77 deletions(-)
>
> diff --git a/net/filter-mirror.c b/net/filter-mirror.c
> index f20240cc9f..4f0e26cc92 100644
> --- a/net/filter-mirror.c
> +++ b/net/filter-mirror.c
> @@ -39,7 +39,6 @@ struct MirrorState {
>       CharBackend chr_in;
>       CharBackend chr_out;
>       SocketReadState rs;
> -    bool vnet_hdr;
>   };
>   
>   static int filter_send(MirrorState *s,
> @@ -48,7 +47,7 @@ static int filter_send(MirrorState *s,
>   {
>       NetFilterState *nf = NETFILTER(s);
>       int ret = 0;
> -    ssize_t size = 0;
> +    ssize_t size = 0, vnet_hdr_len = 0;
>       uint32_t len = 0;
>       char *buf;
>   
> @@ -63,21 +62,18 @@ static int filter_send(MirrorState *s,
>           goto err;
>       }
>   
> -    if (s->vnet_hdr) {
> -        /*
> -         * If vnet_hdr = on, we send vnet header len to make other
> -         * module(like colo-compare) know how to parse net
> -         * packet correctly.
> -         */
> -        ssize_t vnet_hdr_len;
> -
> -        vnet_hdr_len = nf->netdev->vnet_hdr_len;
> +    /*
> +     * The vnet header is the necessary part of filter transfer protocol.
> +     * It make other module(like colo-compare) know how to parse net
> +     * packet correctly. If device is not the virtio-net-pci,
> +     * vnet_hdr_len will be 0.
> +     */
> +    vnet_hdr_len = nf->netdev->vnet_hdr_len;
>   
> -        len = htonl(vnet_hdr_len);
> -        ret = qemu_chr_fe_write_all(&s->chr_out, (uint8_t *)&len, sizeof(len));
> -        if (ret != sizeof(len)) {
> -            goto err;
> -        }
> +    len = htonl(vnet_hdr_len);
> +    ret = qemu_chr_fe_write_all(&s->chr_out, (uint8_t *)&len, sizeof(len));
> +    if (ret != sizeof(len)) {
> +        goto err;
>       }
>   
>       buf = g_malloc(size);
> @@ -232,6 +228,12 @@ static void redirector_rs_finalize(SocketReadState *rs)
>       MirrorState *s = container_of(rs, MirrorState, rs);
>       NetFilterState *nf = NETFILTER(s);
>   
> +    /* Check remote vnet_hdr */
> +    if (rs->vnet_hdr_len != nf->netdev->vnet_hdr_len) {
> +        error_report("filter redirector got a different packet vnet_hdr"
> +        " from local, please check the -device configuration");
> +    }
> +
>       redirector_to_filter(nf, rs->buf, rs->packet_len);
>   }
>   
> @@ -252,7 +254,7 @@ static void filter_redirector_setup(NetFilterState *nf, Error **errp)
>           }
>       }
>   
> -    net_socket_rs_init(&s->rs, redirector_rs_finalize, s->vnet_hdr);
> +    net_socket_rs_init(&s->rs, redirector_rs_finalize, true);
>   
>       if (s->indev) {
>           chr = qemu_chr_find(s->indev);
> @@ -323,20 +325,6 @@ static void filter_mirror_set_outdev(Object *obj,
>       }
>   }
>   
> -static bool filter_mirror_get_vnet_hdr(Object *obj, Error **errp)
> -{
> -    MirrorState *s = FILTER_MIRROR(obj);
> -
> -    return s->vnet_hdr;
> -}
> -
> -static void filter_mirror_set_vnet_hdr(Object *obj, bool value, Error **errp)
> -{
> -    MirrorState *s = FILTER_MIRROR(obj);
> -
> -    s->vnet_hdr = value;
> -}
> -
>   static char *filter_redirector_get_outdev(Object *obj, Error **errp)
>   {
>       MirrorState *s = FILTER_REDIRECTOR(obj);
> @@ -354,31 +342,12 @@ static void filter_redirector_set_outdev(Object *obj,
>       s->outdev = g_strdup(value);
>   }
>   
> -static bool filter_redirector_get_vnet_hdr(Object *obj, Error **errp)
> -{
> -    MirrorState *s = FILTER_REDIRECTOR(obj);
> -
> -    return s->vnet_hdr;
> -}
> -
> -static void filter_redirector_set_vnet_hdr(Object *obj,
> -                                           bool value,
> -                                           Error **errp)
> -{
> -    MirrorState *s = FILTER_REDIRECTOR(obj);
> -
> -    s->vnet_hdr = value;
> -}
> -
>   static void filter_mirror_class_init(ObjectClass *oc, void *data)
>   {
>       NetFilterClass *nfc = NETFILTER_CLASS(oc);
>   
>       object_class_property_add_str(oc, "outdev", filter_mirror_get_outdev,
>                                     filter_mirror_set_outdev);
> -    object_class_property_add_bool(oc, "vnet_hdr_support",
> -                                   filter_mirror_get_vnet_hdr,
> -                                   filter_mirror_set_vnet_hdr);
>   
>       nfc->setup = filter_mirror_setup;
>       nfc->cleanup = filter_mirror_cleanup;
> @@ -393,29 +362,12 @@ static void filter_redirector_class_init(ObjectClass *oc, void *data)
>                                     filter_redirector_set_indev);
>       object_class_property_add_str(oc, "outdev", filter_redirector_get_outdev,
>                                     filter_redirector_set_outdev);
> -    object_class_property_add_bool(oc, "vnet_hdr_support",
> -                                   filter_redirector_get_vnet_hdr,
> -                                   filter_redirector_set_vnet_hdr);
>   
>       nfc->setup = filter_redirector_setup;
>       nfc->cleanup = filter_redirector_cleanup;
>       nfc->receive_iov = filter_redirector_receive_iov;
>   }
>   
> -static void filter_mirror_init(Object *obj)
> -{
> -    MirrorState *s = FILTER_MIRROR(obj);
> -
> -    s->vnet_hdr = false;
> -}
> -
> -static void filter_redirector_init(Object *obj)
> -{
> -    MirrorState *s = FILTER_REDIRECTOR(obj);
> -
> -    s->vnet_hdr = false;
> -}
> -
>   static void filter_mirror_fini(Object *obj)
>   {
>       MirrorState *s = FILTER_MIRROR(obj);
> @@ -435,7 +387,6 @@ static const TypeInfo filter_redirector_info = {
>       .name = TYPE_FILTER_REDIRECTOR,
>       .parent = TYPE_NETFILTER,
>       .class_init = filter_redirector_class_init,
> -    .instance_init = filter_redirector_init,
>       .instance_finalize = filter_redirector_fini,
>       .instance_size = sizeof(MirrorState),
>   };
> @@ -444,7 +395,6 @@ static const TypeInfo filter_mirror_info = {
>       .name = TYPE_FILTER_MIRROR,
>       .parent = TYPE_NETFILTER,
>       .class_init = filter_mirror_class_init,
> -    .instance_init = filter_mirror_init,
>       .instance_finalize = filter_mirror_fini,
>       .instance_size = sizeof(MirrorState),
>   };
> diff --git a/qemu-options.hx b/qemu-options.hx
> index 5f375bbfa6..38c03812a7 100644
> --- a/qemu-options.hx
> +++ b/qemu-options.hx
> @@ -4946,18 +4946,16 @@ SRST
>   
>           ``behind``: insert behind the specified filter (default).
>   
> -    ``-object filter-mirror,id=id,netdev=netdevid,outdev=chardevid,queue=all|rx|tx[,vnet_hdr_support][,position=head|tail|id=<id>][,insert=behind|before]``
> +    ``-object filter-mirror,id=id,netdev=netdevid,outdev=chardevid,queue=all|rx|tx[,position=head|tail|id=<id>][,insert=behind|before]``


I wonder if we break management layer. If yes, maybe it's better to keep 
the vnet_hdr_support here.

Thanks


>           filter-mirror on netdev netdevid,mirror net packet to
> -        chardevchardevid, if it has the vnet\_hdr\_support flag,
> -        filter-mirror will mirror packet with vnet\_hdr\_len.
> +        chardev chardevid, filter-mirror will mirror packet with vnet\_hdr\_len.
>   
> -    ``-object filter-redirector,id=id,netdev=netdevid,indev=chardevid,outdev=chardevid,queue=all|rx|tx[,vnet_hdr_support][,position=head|tail|id=<id>][,insert=behind|before]``
> +    ``-object filter-redirector,id=id,netdev=netdevid,indev=chardevid,outdev=chardevid,queue=all|rx|tx[,position=head|tail|id=<id>][,insert=behind|before]``
>           filter-redirector on netdev netdevid,redirect filter's net
>           packet to chardev chardevid,and redirect indev's packet to
> -        filter.if it has the vnet\_hdr\_support flag, filter-redirector
> -        will redirect packet with vnet\_hdr\_len. Create a
> -        filter-redirector we need to differ outdev id from indev id, id
> -        can not be the same. we can just use indev or outdev, but at
> +        filter. filter-redirector will redirect packet with vnet\_hdr\_len.
> +        Create a filter-redirector we need to differ outdev id from indev id,
> +        id can not be the same. we can just use indev or outdev, but at
>           least one of indev or outdev need to be specified.
>   
>       ``-object filter-rewriter,id=id,netdev=netdevid,queue=all|rx|tx,[vnet_hdr_support][,position=head|tail|id=<id>][,insert=behind|before]``