Add support for compressed form of IPv6

[ghost]

Resolves issue: #2

[ip2location-com]

Something seems wrong with your code. For IP 2001:4860:4860::8844, I am getting 9 chunks when we expect a max of 8 chunks for IPv6.

[ghost]

I do not get that in a test script that makes use of my changes posted in the commit. I get 8 chunks. Is there an extra :?

[ip2location-com]

My test code below:

bn = require("nums.bn")

function checkip(ip)
local R = {ERROR = 0, IPV4 = 4, IPV6 = 6}
if type(ip) ~= "string" then return R.ERROR end

-- check for format 1.11.111.111 for ipv4
local chunks = {ip:match("^(%d+)%.(%d+)%.(%d+)%.(%d+)$")}
if #chunks == 4 then
local ipnum = bn.ZERO
local octet = 0
for x,v in pairs(chunks) do
octet = tonumber(v)
if octet > 255 then return R.ERROR end
ipnum = ipnum + (bn(octet) << (8 * (4 - x)))
end

local ipindex = 0;
if self.ipv4indexbaseaddr > 0 then
  ipindex = ((ipnum >> 16) << 3):asnumber() + self.ipv4indexbaseaddr
end
return R.IPV4, ipnum, ipindex

end

local isIPv6 = false;
local hextets = 8;

if #chunks == 0 then
-- parse the ipv6 string using the expected pattern
for hextet in ip:gmatch("[a-fA-F0-9]*") do
print("hextet: " .. hextet)
table.insert(chunks, hextet)
end
if #chunks > 0 then isIPv6 = true; end
end

-- expand the ipv6 address and add zeroes
if isIPv6 == true then
for i = 1, #chunks do
if chunks[i] == "" then
for j = 1 , hextets - (#chunks - 1) - 1 do
if j == 1 then chunks[i] = "0" end
table.insert(chunks, i, "0")
end
end
end
if chunks[hextets] == "" then chunks[hextets] = "0" end
end

for i = 1, #chunks do
print("chunks " .. i .. ": " .. chunks[i])
end

print("no. of chunks: " .. #chunks)
end

checkip("2001:4860:4860::8844")

The output I'm seeing is:

hextet: 2001
hextet:
hextet: 4860
hextet:
hextet: 4860
hextet:
hextet:
hextet: 8844
hextet:
chunks 1: 2001
chunks 2:
chunks 3: 4860
chunks 4:
chunks 5: 4860
chunks 6:
chunks 7:
chunks 8: 8844
chunks 9:
no. of chunks: 9

Is that how it's supposed to appear?

[ghost]

No. The output of mine looks like this:

Address =       2001:4860:4860::8844
Parsed chunks =         5
Total chunks =  8
1        --     2001
2        --     4860
3        --     4860
4        --     0
5        --     0
6        --     0
7        --     0
8        --     8844

The only difference I see between your test and mine is that I am using single quotes in a variable assignment in the script instead of this function:

checkip("2001:4860:4860::8844")

We have also tested this on our server and it appears to be working properly.

[ip2location-com]

Can you please share your test script? We need to check if there is any issue with our Lua version.

[ghost]

-- provide test ipv6 address, edit here for testing
ip = '2001:4860:4860::8844';
print("Address = ", ip);

-- define empty table and ipv6 expanded address size
local chunks = {};
local hextets = 8;

-- insert data into a table when it represents 'xxxx', null when it doesn't 
for hextet in ip:gmatch("[a-fA-F0-9]*")
do
    table.insert(chunks, hextet);
end

print("Parsed chunks = ", #chunks);

-- iterate through the table
for i = 1, #chunks
do
    -- '::' is added to the table as a null
    if (chunks[i] == "") then
        -- count the remaining spaces in the table to add '0'
        -- and insert with padding
        for j = 1 , hextets - (#chunks - 1) - 1
        do
            if (j == 1) then
                chunks[i] = "0";
            end
            table.insert(chunks, i, "0");
        end
    end
end

print("Total chunks = ", #chunks);

if (chunks[hextets] == "") then
    chunks[hextets] = "0";
end

for key, value in pairs(chunks)
do
    print(key, " -- " , value);
end

I am using 5.4.1. It has also been tested in version 5.3 on our server.

Thanks for the help. :)

[ip2location-com]

I'm getting the below:

Address = 2001:4860:4860::8844
Parsed chunks = 9
Total chunks = 9
1 -- 2001
2 --
3 -- 4860
4 --
5 -- 4860
6 --
7 --
8 -- 8844
9 --

Starting to look like an issue with my Lua 5.3 running on ZeroBrane Studio.

[ghost]

I am running it in a standard terminal on Manjaro Linux. You might try that just to confirm.

[ip2location-com]

Works just fine in Debian. So I'll merge this pull request first then check on the ZeroBrane issue.

Address = 2001:4860:4860::8844
Parsed chunks = 5
Total chunks = 8
1 -- 2001
2 -- 4860
3 -- 4860
4 -- 0
5 -- 0
6 -- 0
7 -- 0
8 -- 8844

[ghost]

Thank you for the quick response!