Re: [Qemu-devel] [PULL 00/14] Net patches

[Wen Congyang]

On 03/08/2016 05:06 PM, Zhang Chen wrote:
> 
> 
> On 03/08/2016 03:56 PM, Jason Wang wrote:
>>
>> On 03/08/2016 03:50 PM, Wen Congyang wrote:
>>> On 03/08/2016 03:33 PM, Jason Wang wrote:
>>>> On 03/08/2016 12:51 PM, Peter Maydell wrote:
>>>>> On 7 March 2016 at 10:12, Jason Wang <address@hidden> wrote:
>>>>>> The following changes since commit 
>>>>>> 1464ad45cd6cdeb0b5c1a54d3d3791396e47e52f:
>>>>>>
>>>>>>    Merge remote-tracking branch 
>>>>>> 'remotes/armbru/tags/pull-qapi-2016-03-04' into staging (2016-03-06 
>>>>>> 11:53:27 +0000)
>>>>>>
>>>>>> are available in the git repository at:
>>>>>>
>>>>>>    https://github.com/jasowang/qemu.git tags/net-pull-request
>>>>>>
>>>>>> for you to fetch changes up to a2f2e45c6edbba9e1961056fa77c696208b40c8e:
>>>>>>
>>>>>>    net: check packet payload length (2016-03-07 10:15:48 +0800)
>>>>>>
>>>>>> ----------------------------------------------------------------
>>>>>>
>>>>>> - a new netfilter implementation: mirror
>>>>>> - netfilter could be disabled and enabled through qom-set now
>>>>>> - fix netfilter crash when specifiying wrong parameters
>>>>>> - rocker switch now can allow user to specifiy world
>>>>>> - fix OOB access for ne2000
>>>>> Hi; I'm afraid this makes "make check" hang for me (Linux, x86-64):
>>>>>
>>>>> TEST: tests/test-netfilter... (pid=26854)
>>>>>    /i386/netfilter/addremove_one:                                       OK
>>>>>    /i386/netfilter/remove_netdev_one:                                   OK
>>>>>    /i386/netfilter/addremove_multi:                                     OK
>>>>>    /i386/netfilter/remove_netdev_multi:                                 OK
>>>>> PASS: tests/test-netfilter
>>>>> TEST: tests/test-filter-mirror... (pid=26858)
>>>>>    /i386/netfilter/mirror:
>>>>>
>>>>> (consistently, every time I run make check, on the same test).
>>>>>
>>>>> thanks
>>>>> -- PMM
>>>> Sorry, it manages to pass on my machine before submitting the pull
>>>> request. But when I re-try this several times, it fails.
>>>>
>>>> This probably means we have bug in mirror implementation. Chen and
>>>> Congyang, please try to fix this bug and resubmit a new version of the
>>>> patch.
>>>>
>>>> Will drop mirror from this pull request and submit a V2.
>>> OK. what is the version of the kernel that you use?
>> 4.2 but probably unrelated. Gdb shows the test wait at recv().
> 
> Hi~ Jason.
> 
> I found the reason for this problem is that
> unix_connect() have not connect to sock_path before iov_send().

After unix_connect() returns, the connection is established.
qemu char device will call qemu_chr_accept() after the connection
is established. If we send data before qemu_chr_accept() is called,
the data will be dropped by qemu char device:
static int tcp_chr_write(CharDriverState *chr, const uint8_t *buf, int len)     
    
{                                                                               
    TCPCharDriver *s = chr->opaque;                                             
    if (s->connected) {                                                         
...
        return ret;                                                             
    } else {                                                                    
        /* XXX: indicate an error ? */                                          
        return len;                                                             
    }                                                                           
}                              

We should wait some to let qemu_chr_accept() is called before sending
data.

Thanks
Wen Congyang

> It need time to establish connection. so can we fix it with usleep()
> like this:
> 
>     recv_sock = unix_connect(sock_path, NULL);
>     g_assert_cmpint(recv_sock, !=, -1);
> +    usleep(1000);
> 
>     ret = iov_send(send_sock[0], iov, 2, 0, sizeof(size) + sizeof(send_buf));
>     g_assert_cmpint(ret, ==, sizeof(send_buf) + sizeof(size));
>     close(send_sock[0]);
> 
>     ret = qemu_recv(recv_sock, &len, sizeof(len), 0);
> 
> 
> 
>>> Thanks
>>> Wen Congyang
>>>
>>>> Thanks
>>>>
>>>>
>>>> .
>>>>
>>>
>>
>>
>> .
>>
>