Re: inconsistent address treatment.

[Stephen Clark <sclark46@earthlink.net>]

On 12/26/2010 07:47 AM, Jan Engelhardt wrote:
> On Sunday 2010-12-26 13:10, Amos Jeffries wrote:
>
>    
>> On 25/12/10 10:48, Jan Engelhardt wrote:
>>      
>>> On Friday 2010-12-24 16:32, Stephen Clark wrote:
>>>        
>>>>>>> Because -d takes a prefix and --to-source takes an address range.
>>>>>>>                
>>>>>> So? you can't parse
>>>>>> 205.201.149.214/32-205.201.149.218/32
>>>>>>              
>>>>> a.b.c.d/32 is a prefix notation, even though it represents a single
>>>>> address. IMO it does not make sense to use a prefix notation in an
>>>>> interval, so I don't see why the parser should handle it. AFAICS, other
>>>>> commands such as 'ip' from iproute don't accept /32 prefixes where a
>>>>> single address is expected either.
>>>>>            
>>>> Well It is just one more idiosyncrasy one has to remember, when to me there
>>>> is no obvious reason
>>>>          
>>> Historical reasons.
>>>
>>> Possible extra explanations:
>>>
>>> - DNAT was added later than the -s argument, and someone thought
>>>    it's better to use a range, since a range can be more expressive
>>>    than addr[/prefixlen] for the same memory usage.
>>> - On the other hand, since iptables also accepts addr[/mask], and it
>>>    also allows /masks that are not representable as a /prefixlen, it
>>>    is not necessarily specifying a contiguous range which may be
>>>    useless to use with DNAT to some.
>>>        
>> FWIW: we (Squid project) use the syntax "ip[-ip][/mask]". This is simple enough
>> to parse and is a bit more flexible.
>>      
> Indeed, but we don't have the space for it ;-)
> There are just two uint32s available in the current struct ipt_ip,
> so it's either ip-ip or ip/mask.
> Of course, in the near future, the ipv4 match can be extended just like
> other extensions (revision bump).
>
>    
That is a reasonable answer.


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