Re: [Qemu-devel] [PATCH V4 03/12] net/filter-mirror.c: Make filter_mirror_send support vnet support.

[Jason Wang <jasowang@redhat.com>]

On 2017年05月12日 09:41, Zhang Chen wrote:
> In this patch, if vnet_hdr=on we change the send packet format from
> struct {int size; const uint8_t buf[];} to {int size; int vnet_hdr_len; const uint8_t buf[];}.
> make other module(like colo-compare) know how to parse net packet correctly.
>
> Signed-off-by: Zhang Chen <zhangchen.fnst@cn.fujitsu.com>
> ---
>   net/filter-mirror.c | 35 ++++++++++++++++++++++++++++++-----
>   1 file changed, 30 insertions(+), 5 deletions(-)
>
> diff --git a/net/filter-mirror.c b/net/filter-mirror.c
> index 3766414..64323fc 100644
> --- a/net/filter-mirror.c
> +++ b/net/filter-mirror.c
> @@ -44,10 +44,11 @@ typedef struct MirrorState {
>       SocketReadState rs;
>   } MirrorState;
>   
> -static int filter_mirror_send(CharBackend *chr_out,
> +static int filter_mirror_send(MirrorState *s,
>                                 const struct iovec *iov,
>                                 int iovcnt)
>   {
> +    NetFilterState *nf = NETFILTER(s);
>       int ret = 0;
>       ssize_t size = 0;
>       uint32_t len = 0;
> @@ -59,14 +60,38 @@ static int filter_mirror_send(CharBackend *chr_out,
>       }
>   
>       len = htonl(size);
> -    ret = qemu_chr_fe_write_all(chr_out, (uint8_t *)&len, sizeof(len));
> +    ret = qemu_chr_fe_write_all(&s->chr_out, (uint8_t *)&len, sizeof(len));
>       if (ret != sizeof(len)) {
>           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;
> +
> +        if (nf->netdev->using_vnet_hdr) {
> +            vnet_hdr_len = nf->netdev->vnet_hdr_len;
> +        } else if (nf->netdev->peer->using_vnet_hdr) {
> +            vnet_hdr_len = nf->netdev->peer->vnet_hdr_len;

Still questionable here, may need a comment to explain.

> +        } else {
> +            error_report("filter get vnet_hdr_len failed");

Why need error here, could we just use zero?

Thanks

> +            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);
>       iov_to_buf(iov, iovcnt, 0, buf, size);
> -    ret = qemu_chr_fe_write_all(chr_out, (uint8_t *)buf, size);
> +    ret = qemu_chr_fe_write_all(&s->chr_out, (uint8_t *)buf, size);
>       g_free(buf);
>       if (ret != size) {
>           goto err;
> @@ -142,7 +167,7 @@ static ssize_t filter_mirror_receive_iov(NetFilterState *nf,
>       MirrorState *s = FILTER_MIRROR(nf);
>       int ret;
>   
> -    ret = filter_mirror_send(&s->chr_out, iov, iovcnt);
> +    ret = filter_mirror_send(s, iov, iovcnt);
>       if (ret) {
>           error_report("filter_mirror_send failed(%s)", strerror(-ret));
>       }
> @@ -165,7 +190,7 @@ static ssize_t filter_redirector_receive_iov(NetFilterState *nf,
>       int ret;
>   
>       if (qemu_chr_fe_get_driver(&s->chr_out)) {
> -        ret = filter_mirror_send(&s->chr_out, iov, iovcnt);
> +        ret = filter_mirror_send(s, iov, iovcnt);
>           if (ret) {
>               error_report("filter_mirror_send failed(%s)", strerror(-ret));
>           }