[Spice-devel] [PATCH] Use non-zero data for initial ping

[Yaniv Kaul]

On 02/14/2012 10:40 AM, Alon Levy wrote:

<SNIP>

>
> Other then that looks good, and like you say probably better - although
> I'm not convinced that by checking several common desktop compression
> programs you are checking whatever compression scheme vpn's are using.

VPNs usually use DEFLATE (which is close to gzip).
Both SSL/TLS and IPsec do, at least.
Y.

> But it's probably a good indication of the compressability.
>
>> +    /* this produces ascending and descending byte runs which vary in offset
>> +     * every 512 bytes, preventing prevents compression from being able to
>> +     * influence the resulting size of the ping data too much */
>> +    for(i = 0; i<  size; i++) {
>> +        div_t result = div(i, 256);
>> +        if(result.quot % 2 == 0) {
>> +            ping_data[i] = (result.quot + 1) * result.rem;
>> +        } else {
>> +            ping_data[i] = 512 - (result.quot * result.rem);
>> +        }
>>       }
>> +
>> +    spice_marshaller_add(m, ping_data, size);
>>   }
>>
>>   void main_channel_push_mouse_mode(MainChannel *main_chan, int current_mode,
>> -- 
>> 1.7.9
>>
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