Re: [PATCH] Change xt_TOS v1 target to zero-out semantic

[Patrick McHardy <kaber@trash.net>]

Jan Engelhardt wrote:
> On Dec 17 2007 14:04, Patrick McHardy wrote:
>
>> I'd prefer:
>>
>> --set-tos: set exact value, no mask
>> --or-tos: set single bits
>> --xor-tos: flip single bits
>> --and-tos: mask single bits
>>
> 
> Ok, I'll add these. However, since they get transformed to xmark 
> internally, they would normally be displayed as
> 
> 	--set-tos value/mask (iptables-save, iptables -nL)
> 	TOS set value/mask (iptables -L)
> 
> Is that ok, or should I figure out some math to transform it back to 
> --{or,xor,and}-tos for the human-readable (iptables -L) case?


That would be better. The mark patch I pointer you to some
time ago did this:

+print_mark(unsigned long mark, unsigned long mask, int numeric)
  {
-       printf("0x%lx ", mark);
+       if (mask == 0)
+               printf("set 0x%lx ", mark);
+       else if (mark == ~mask)
+               printf("or 0x%lx ", mark);
+       else if ((mark & mask) == 0)
+               printf("set 0x%lx/0x%lx ", mark, ~mask);
+       else {
+               if (mask != ~0UL)
+                       printf("and 0x%lx ", mask);
+               if (mark)
+                       printf("xor 0x%lx ", mark);
+       }
  }

which I guess would also work for tos.