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Date:      Thu, 4 Aug 2016 10:29:30 +0800
From:      Julian Elischer <julian@freebsd.org>
To:        "Dr. Rolf Jansen" <rj@obsigna.com>, ipfw mailing list <ipfw@freebsd.org>
Subject:   Re: your thoughts on a particualar ipfw action.
Message-ID:  <6253540c-9692-7869-825f-5453505d7e2b@freebsd.org>
In-Reply-To: <DA5D1FAE-79D9-4A19-8EFB-951C926265A0@obsigna.com>
References:  <7f573fc4-2820-ebd3-7b15-d8a1cd023372@freebsd.org> <AE91DE1F-82B5-413C-826C-085231906C5F@obsigna.com> <9fb7a057-aa02-9743-db9f-d4eef6df16f0@freebsd.org> <DA5D1FAE-79D9-4A19-8EFB-951C926265A0@obsigna.com>

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Wow, this is getting to be a very useful tool.
thanks for all the work. I look forward to the port..

On 4/08/2016 5:53 AM, Dr. Rolf Jansen wrote:
>> Am 03.08.2016 um 11:13 schrieb Julian Elischer <julian@freebsd.org>:
>>
>> On 2/08/2016 8:50 PM, Dr. Rolf Jansen wrote:
>>>> Am 02.08.2016 um 05:08 schrieb Julian Elischer <julian@freebsd.org>:
>>>>
>>>> looking for thoughts from people who know the new IPFW features well..
>>>>
>>>>
>>>> A recent addition to our armory is the geoip program that, given an address can tell you what country it is in and given a country code, can give an ipfw table that describes all the ip addresses in that country.
>>>>
>>>> SO I was thinking how to use this, and the obvious way would be to have a set of rules for each country, and use the "skipto tablearg" facility to skip to the right rules for each country. But the trouble is that a tablearg skipto is very inefficient. It's also a hard thing to set up with a set of rules for each country (how many countries are there in the internet allocation system?).
>>> As of today a total of 236 country codes are in use for IPv4 delegations. If this helps for anything, a command line switch to the geoip tool could be added for letting it output the country code (as the hex encoded CC taken as a plain decimal integer) as the value for the given table entry. In the moment you can give one value for all entries generated by geoip, with this switch set, the output of geoip could look like:
>>>
>>> $ geoip -t "DE:BR:US" -x
>>> ...
>>> table 0 add 93.157.48.0/21 4445
>>> table 0 add 93.158.236.0/22 4252
>>> table 0 add 93.159.96.0/19 4445
>>> table 0 add 93.159.248.0/21 4445
>>> table 0 add 93.180.72.0/21 4445
>>> table 0 add 93.180.152.0/21 4445
>>> table 0 add 93.181.0.0/18 4445
>>> table 0 add 93.183.0.0/18 5553
>>> ...
>>>
>>> Given that ...
>>> 0x4445 = 'DE'
>>> 0x4252 = 'BR'
>>> 0x5553 = 'US'
>> well it would have to be the decimal value so DE would be 6869, as while 4445 works 444F is a problem :-)
> Yes, you're right, I was taken away by the wave of enthusiasm, before thinking about the subject up to the end.
>
>> 0x444F would work but we waste even more address space.  You'd have to multiply the numbers by some scaler, because adjacent numbers would not be enough for one rule to do something and another rule to skip on to somewhere else. (well, you could have multiple rules at the same number but that has its limitations.
>> The idea would certainly work. it would mean setting aside all  the rules  between 6565 and 9090 however.
>> A more compact encoding could be something like ((name[0]-'A') * 32)+(name[1]-'A')) multiplied by some 'step' (maybe 10 by default) and offset by a given offset.
>>
>> so AF (Afghanistan) would be the first 0*32+5  * 10 would give an offset of 50.. plus a user supplied offset turns it into say, 15050..
> I understand the reasons, however, any complicated encoding will defeat the idea of the value can be sort of numeric mnemonic for the country code – well, so it is. I elaborated on your idea and came-up with the following formula:  val = (C1-60)*1000 + C2*10 + offset. The offset can be given as the parameter to the -x flag.
>
> $ geoip -t "DE:BR:US" -4 -x 30000
> ...
> table 0 add 93.157.48.0/21 38690
> table 0 add 93.158.236.0/22 36820
> table 0 add 93.159.96.0/19 38690
> table 0 add 93.159.248.0/21 38690
> table 0 add 93.180.72.0/21 38690
> table 0 add 93.180.152.0/21 38690
> table 0 add 93.181.0.0/18 38690
> table 0 add 93.183.0.0/18 55830
> ...
>
> The limits (without offset) are:
> AA = 5650  -- actually AD = 5680
> ZZ = 30900
>
> With this formula, the offset must be less than 34735. Although, this wastes a considerable amount of rule number space, the advantage is that the numbers are still accessible by mental arithmetic, and the other constraint of having a step > 1 is fulfilled as well. Anyway, this one is not graved in stone, we can agree on another one.
>
>> or there could be a translation into iso3166 numeric codes where Afghanistan is 004, but then you have the worry of keeping the data up to date as they add new country codes, which in my opinion makes it a bad solution.
> Agreed, too much dependencies, let's forget the numeric iso codes.
>
>
> BTW: The ipdb tools are now IPv6 aware.
>
> $ geoip 2001:1900:2254:206a::50:5
> 2001:1900:2254:206a::50:5 in 2001:1900:0:0:0:0:0:0 - 2001:1900:ffff:ffff:ffff:ffff:ffff:ffff in US
>
> $ geoip -t "DE:BR:US" -p
> ...
> ...
> 217.194.64.0/20
> 217.194.224.0/20
> 217.195.0.0/20
> 217.195.32.0/20
> 217.197.80.0/20
> 217.198.128.0/20
> 217.198.240.0/20
> 217.199.64.0/20
> 217.199.192.0/20
> 217.224.0.0/11
> 2001:400:0:0:0:0:0:0/32
> 2001:408:0:0:0:0:0:0/32
> 2001:418:0:0:0:0:0:0/32
> 2001:420:0:0:0:0:0:0/32
> 2001:428:0:0:0:0:0:0/32
> 2001:430:0:0:0:0:0:0/32
> 2001:438:0:0:0:0:0:0/32
> ...
> ...
>
> $ geoip -t "" -p | wc -l
>    137097
>
> For processing only IPv4 addresses, add the -4 switch (this reproduces the old behaviour)
> $ geoip -4 -t "" -p | wc -l
>    106637
>
> For processing only IPv6 addresses, add the -6 switch
> $ geoip -6 -t "" -p | wc -l
>     30460
>
> 106637+30460 = 137097
>
> After running 'make install' of the new version, the IP database needs to be updated using the ipdb-update.sh script. This will now generate two binary database files (*.v4 and *.v6).
>
> Best regards
>
> Rolf
>

>




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