[En-Nut-Discussion] local tcp port randomisation

Harald Kipp harald.kipp at egnite.de
Tue Jul 3 16:30:33 CEST 2012

Hi Nathan,

On 03.07.2012 16:13, Nathan Moore wrote:
> Is there any reason not to just use the negative port numbers (if you
> interpret them as signed int so top bit = 1) as the ephemeral ports?
> The range testing is greatly simplified.

Let me resend my code fragment:

 ticks = (uint16_t) NutGetMillis();
 if (first)
  port = ticks;
  port += ticks & 0x000F;
 port |= 0xC000;

Where do you think that signed interpretation combined with a increased range of 32768 to 65535 could simplify the code above. Note, that the IANA range of 49152 to 65535 includes all shorts with two MSBs set.



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