Offline algorithm to turn an IP4 address into a country name

[Virchanza]

I'm currently writing a program that will have no access to the internet.

I need to be able to turn IP4 addresses into country names. (It doesn't have to be 100% accurate). So the code would be something like:

if ( 62 == ip_address.first_octet )
    return "Ireland";

else if ( 41 == ip_address.first_octet )
    return "Nigeria";

else if ( 158 == ip_address.first_octet )
    return "Chile";

else
    return 0;

Does anyone have such code available? I'd really appreciate if you could post it here (it can be in any programming language at all).

[snafu777]

Do you have a list of all the country codes? I could find them I'm sure online, but too lazy for such things. You give me a list and ill write ya something in bash

[Virchanza]

It's grand, I've got all the data I need, now I just have to parse it.

I'll post it here when I've got it done.

[shadowzero]

Found a sample actually: http://www.codeproject.com/KB/aspnet/aspxcode_net.aspx

[Virchanza]

Here's the C code. It turns 32-Bit IP address numbers into a two-letter country code:

http://virjacode.com/ip_address_c_code.txt

[Gitsnik]

Sorry Virchanza I only just saw this. I am the first to admit this isn't running from my BT system, but it might make things easier for you

# geoiplookup 173.245.60.120 | awk -F:\  '{print $2}' | sed 's/,.*//'

It used to be that I would download a copy of the lookup tables daily from a particular site (via a crontab), but it looks like the latest version has a program built to let you update it when you are online anyway.

You have the benefit then of looking up the information from a data file, which is updateable and modifiable, AND you should have a lot less code than a sequence of if statements like that. Would save you a lot of time.

For those following along at home, there are even plugins to Apache, lighthttpd, pecl, rubnet and ruby gems for GeoIP lookups. I used to use it to plot IP addresses to approximate GPS coordinates on a world map (a nifty way of using an IRC bot really, nothing more).

[Virchanza]

Is anyone here handy with Java and Eclipse? (I don't have much experience with them at all, I stick to C and C++).

I have to do an Interactive Media Design project for college, and the lecturer is using a Java library so I have to try put something together in Java.

So I took my C code and tried to turn it into Java code. Here's the contents of "IP_Converter.java":

http://virjacode.com/IP_Converter.txt (This file is 1.8 megabytes)

When I try to build this in Eclipse, I get:

Too many constants, the constant pool for IP_Converter would exceed 65536 entries IP_Converter.java /processing_tesing/src line 2 Java Problem

Is there anything I can do to get around this?

[Virchanza]

OK I've decided to go with a different strategy. Instead of having a boat load of IF statements, I'm gonna have a class that loads a CSV file into a vector.

Anyway, first of all, here's the format of the CSV file:

Two-letter country code,starting ip,ending ip

So here's the first few entries of the CSV file:

ad,3265150976,3265159167
ad,1432264704,1432272895
ad,1538998272,1539006463
ae,3265921024,3265986559
ae,3286564864,3286630399
ae,3561742336,3561750527
ae,3582205952,3582214143
ae,3576299520,3576365055
ae,3651403776,3651534847
ae,1357053952,1357119487

Now I actually have to code this in Java..... but since I'm shite at Java I decided to write it in C++ first, get it working, and then see about bending and squeezing it into Java.
Anyway here's what I've got:

#include <fstream>   // ifstream
#include <vector>    // vector
#include <string>    // string
#include <cstdlib>   // strtoul
#include <iostream>  // ostream
#include <stdint.h>  // uint_fast32_t

struct RangeEntry {

    uint_fast32_t a, z;

    char cty_code[3];

};

class IP_Tracer {

protected:

    std::ifstream csv_file;

    typedef std::vector<RangeEntry> ContainerType;
    
    ContainerType ranges;

public:

    IP_Tracer(char const *const arg_filename) : csv_file(arg_filename)
    {
        if ( !csv_file.is_open() )
            throw -1;

        std::string str;

        while ( std::getline(csv_file,str) )
        {
            if ( str.length() < 18 )  // Start off with aa,1.1.1.1,1.1.1.1
                continue;

            RangeEntry re;

            char const *const p = str.c_str();

            re.cty_code[0] = p[0];
            re.cty_code[1] = p[1];
            re.cty_code[2] = '\0';

            str.erase(0,3); // Leaves us with 1.1.1.1,1.1.1.1

            std::string const &a = str.substr(  0, str.find_first_of(',')  );
            
            std::string const &z = str.substr(  str.find_first_of(',') + 1  );

            re.a = std::strtoul( a.c_str(), 0, 10 );
 
            re.z = std::strtoul( z.c_str(), 0, 10 );

            ranges.push_back(re);
        }
    }

    void Display_All_Ranges(std::ostream &os) const
    {
        for ( ContainerType::const_iterator p = ranges.begin(); p != ranges.end(); ++p )
        {
            os << p->cty_code << " / " << p->a << " / " << p->z << '\n';
        }        
    }

    char const *IP_to_Country( uint_fast32_t const ip ) const
    {
        // Return value is valid until IP_Tracer object is destroyed

        for ( ContainerType::const_iterator p = ranges.begin(); p != ranges.end(); ++p )
        {
            if ( ip >= p->a && ip <= p->z )
                return p->cty_code;
        }

        return 0;
    }
};

Seeing as how my CSV file is 1.8 MB, containing over 28 thousand lines, I thought there would be a delay of a few seconds when I create an object of this class.... but funnily enough it's pretty much instantaneous on my laptop.

Now I just have to try turn the above class into Java code I tried playing around with Eclipse, but when I hit Build, it seems like it's actually running the program. It's giving me errors about unhandled exceptions...... so either it's running the program and exceptions are being thrown...... or the Java compiler is telling me that every exception needs to be caught in Java...... I dunno I'm not a Java guy.

[Virchanza]

OK I'm trying to turn the above C++ code in Java code. Could someone give me a hand please? I'm hopeless at Java. Here's what I have so far:

import java.io.*;
import java.util.*;

class RangeEntry {

    long a, z;

    String cty_code;

};

public class IP_Tracer {

    protected Vector<RangeEntry> ranges;

    public IP_Tracer(String arg_filename)
    {
        FileInputStream fis;
        DataInputStream dis;
        BufferedReader br;
        
        fis = new FileInputStream(arg_filename);
        
        dis = new DataInputStream(fis);
        
        br = new BufferedReader( new InputStreamReader(dis) );
        
        String str;

        while ( (str = br.readLine()) != null )
        {
            if ( str.length() < 18 )  // Start off with aa,1.1.1.1,1.1.1.1
                continue;

            RangeEntry re = new RangeEntry();

            re.cty_code = str.substring(0,1);
            
            str = str.substring(3); // Leaves us with 1.1.1.1,1.1.1.1

            String a = str.substring(  0, str.indexOf(',') - 1 );
            
            String z = str.substring(  str.indexOf(',') + 1  );

            re.a = Long.valueOf(a);
 
            re.z = Long.valueOf(z);
            
            ranges.add(re);
        }
    }

    String IP_to_Country( long ip )
    {
        for ( RangeEntry re : ranges )
        {
            if ( ip >= re.a && ip <= re.z )
                return re.cty_code;
        }

        return null;
    }
};

Is that looking alright?

When I hit Build, it gave me:

Description    Resource    Path    Location    Type
Unhandled exception type FileNotFoundException    IP_Tracer.java    /src    line 22    Java Problem
Unhandled exception type IOException    IP_Tracer.java    /src    line 30    Java Problem

Why is it moaning about unhandled exceptions? Do you need to have a try-catch block for every exception in Java?!

[Gitsnik]

Why is it moaning about unhandled exceptions? Do you need to have a try-catch block for every exception in Java?!

Just around the statements on line 22 and 30.

I usually cheat (though it's been a while):

try {
blah
} catch exception (e) {
meh
}

Saves having to argue with IOExceptions and all the rest. You'll have to look up the proper format, it has been a few years.