On 08/06/2015 03:28 PM, Yang Hongyang wrote:
>
>
> On 08/06/2015 03:13 PM, Jason Wang wrote:
>>
>>
>> On 08/04/2015 04:30 PM, Yang Hongyang wrote:
>>> Capture packets that will be sent.
>>>
>>> Signed-off-by: Yang Hongyang <yan...@cn.fujitsu.com>
>>> ---
>>> net/net.c | 66
>>> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
>>> 1 file changed, 65 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/net/net.c b/net/net.c
>>> index 03b2296..efccd56 100644
>>> --- a/net/net.c
>>> +++ b/net/net.c
>>> @@ -569,6 +569,42 @@ int qemu_can_send_packet(NetClientState *sender)
>>> return 1;
>>> }
>>>
>>> +static ssize_t filter_receive_iov(NetClientState *nc, int chain,
>>> + NetClientState *sender,
>>> + unsigned flags,
>>> + const struct iovec *iov,
>>> + int iovcnt)
>>> +{
>>> + ssize_t ret = 0;
>>> + NetFilterState *nf = NULL;
>>> + ssize_t size = iov_size(iov, iovcnt);
>>> +
>>> + QTAILQ_FOREACH(nf, &nc->filters, next) {
>>> + if (nf->chain == chain || nf->chain == NET_FILTER_ALL) {
>>> + ret = nf->info->receive_iov(nf, sender, flags, iov,
>>> iovcnt);
>>> + if (ret == size) {
>>> + return ret;
>>> + }
>>> + }
>>> + }
>>> +
>>> + return ret;
>>> +}
>>> +
>>> +static ssize_t filter_receive(NetClientState *nc, int chain,
>>> + NetClientState *sender,
>>> + unsigned flags,
>>> + const uint8_t *data,
>>> + size_t size)
>>> +{
>>> + struct iovec iov = {
>>> + .iov_base = (void *)data,
>>> + .iov_len = size
>>> + };
>>> +
>>> + return filter_receive_iov(nc, chain, sender, flags, &iov, 1);
>>> +}
>>> +
>>> ssize_t qemu_deliver_packet(NetClientState *sender,
>>> unsigned flags,
>>> const uint8_t *data,
>>> @@ -640,6 +676,7 @@ static ssize_t
>>> qemu_send_packet_async_with_flags(NetClientState *sender,
>>> NetPacketSent
>>> *sent_cb)
>>> {
>>> NetQueue *queue;
>>> + int ret;
>>>
>>> #ifdef DEBUG_NET
>>> printf("qemu_send_packet_async:\n");
>>> @@ -650,6 +687,18 @@ static ssize_t
>>> qemu_send_packet_async_with_flags(NetClientState *sender,
>>> return size;
>>> }
>>>
>>> + /* Let filters handle the packet first */
>>> + ret = filter_receive(sender, NET_FILTER_OUT, sender, flags,
>>> buf, size);
>>> + if (ret == size) {
>>> + return size;
>>> + }
>>> +
>>> + ret = filter_receive(sender->peer, NET_FILTER_IN,
>>> + sender, flags, buf, size);
>>> + if (ret == size) {
>>> + return size;
>>> + }
>>
>> I think we can just trust the return value of filter_receive(), no need
>> to check it against iov_size.
>
> You mean:
> if (ret)
> return ret;
> ? We need to check ret however.
Yes, but the problem is you check it against size. What if
filter_receive() returns a value which is greater than 0 but smaller
than size. If this could not happen, probably no need to check. Not a
must but better to change this.
>
>>
>> Also sent_cb was lost track if the packet was held by filter which seems
>> wrong.
>
> So we need to extend the params of filter's receive_iov API, add a
> sent_cb
> param.
Yes.
> BTW, it seems that sent_cb will only been called when packet is
> queueed and then sent, if the packet being sent directly sent_cb won't
> be called? am I right? or I missed somthing from the code...
Yes, but if for some reason it couldn't. Sent cb is usually used to let
main loop to re-poll network backend.
>
>>
>> [...]
>> .
>>
>
