80 lines
3.5 KiB
C#
80 lines
3.5 KiB
C#
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using System;
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using System.Collections.Generic;
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using System.Linq;
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namespace IP_Filtering
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{
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class Program
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{
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static void Main(string[] args)
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{
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Console.WriteLine(IsInStringContext("192.168.0.1")); //Should return true
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Console.WriteLine(IsInStringContext("192.168.0.2")); //Should return true
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Console.WriteLine(IsInStringContext("192.168.0.3")); //Should return false
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Console.WriteLine(IsInStringContext("192.168.1.133")); //Should return true (in range)
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Console.WriteLine(IsInStringContext("192.168.4.54")); //Should return true (in range)
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Console.WriteLine(IsInStringContext("192.168.4.53")); //Should return false (not in range)
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Console.WriteLine(IsInStringContext("192.168.2.34")); //Should return true (in CIDR range)
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Console.WriteLine(IsInStringContext("192.168.3.34")); //Should return false (not in CIDR range)
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Console.WriteLine(IsInStringContext("192.168.3.212")); //Should return true (in CIDR range) !!
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}
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private static readonly List<string> StringDataContext = new List<string>{
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"192.168.0.1", "192.168.0.2", "192.168.1.0 - 192.168.1.255", "192.168.2.0/24", "192.168.3.128/25", "192.168.4.54 - 192.168.4.62"
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};
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public static bool IsInStringContext(string ip)
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{
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//Check if it's explicitly in the data context
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if (StringDataContext.Exists(d => d == ip))
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return true;
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var givenIPOctets = ip.Split('.');
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//Next, check if it's in range
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//For this, I am going to assume IP ranges can only be a range of the last octet
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foreach (string address in StringDataContext.Where(sdc => sdc.Contains('-')))
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{
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string[] addresses = address.Replace(" ", "").Split('-');
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string[] firstAddressOctets = addresses[0].Split('.');
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string[] secondAddressOctets = addresses[1].Split('.');
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//Make sure first three octets are the same
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if (givenIPOctets[0] != firstAddressOctets[0] ||
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givenIPOctets[1] != firstAddressOctets[1] ||
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givenIPOctets[2] != firstAddressOctets[2])
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{
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continue;
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}
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int ipAddressLastOctet = int.Parse(givenIPOctets[3]);
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int firstAddressLastOctet = int.Parse(firstAddressOctets[3]);
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int secondAddressLastOctet = int.Parse(secondAddressOctets[3]);
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if (ipAddressLastOctet >= firstAddressLastOctet && ipAddressLastOctet <= secondAddressLastOctet)
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return true;
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}
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//Lastly, check if it's in CIDR range.
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//Again, I'm going to assume IP ranges can only be part of the last octet.
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foreach (string address in StringDataContext.Where(sdc => sdc.Contains('/')))
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{
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string[] ipAddress = address.Split('/');
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string[] octets = ipAddress[0].Split('.');
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if (givenIPOctets[0] != octets[0] ||
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givenIPOctets[1] != octets[1] ||
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givenIPOctets[2] != octets[2])
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{
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continue;
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}
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int maxOctet = (int)Math.Pow(2, 32 - int.Parse(ipAddress[1])) + int.Parse(octets[3]);
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if (int.Parse(givenIPOctets[3]) >= int.Parse(octets[3]) && int.Parse(givenIPOctets[3]) <= maxOctet)
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return true;
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}
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return false;
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}
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}
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}
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