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

[Zhang Chen <zhangchen.fnst@cn.fujitsu.com>]

On 05/15/2017 11:28 AM, Jason Wang wrote:
>
>
> 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.
>

OK, I will add comments in next version.

>> +        } else {
>> +            error_report("filter get vnet_hdr_len failed");
>
> Why need error here, could we just use zero?

Yes,we can.

Thanks
Zhang Chen

>
> 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));
>>           }
>
>
>
> .
>

-- 
Thanks
Zhang Chen