关于专用网络IP过滤

Question

I am trying to filter out private network IPfrom URLs.
Previously I had this code

 if(!sCurrentLine.startsWith("192.168") && !sCurrentLine.startsWith("172.") && !sCurrentLine.startsWith("10.")&& !sCurrentLine.startsWith("127.0.0"))

Data Example

10.1.1.83/nagiosxi/
10.1.1.83/nagiosxi//rr.php?uid=18-c96b5fb53f9
127.0.0.1/tkb/internet/
172.18.20.200/cgi-bin/topstats.pl?submit_type=topstats&time=00:2

Here is my new code

 Pattern privateIp=Pattern.compile("(^127\\.0\\.0\\.1)|(^10\\.)|(^172\\.1[6-9]\\.)|(^172\\.2[0-9]\\.)|(^172\\.3[0-1]\\.)|(^192\\.168\\.)");
 while((sCurrentLine=br.readLine())!=null)
{

            Matcher pnm=privateIp.matcher(sCurrentLine);

            if(!pnm.matches())
            {
              System.out.println("not match");

            }
}

I am thinking of using Pattern Match. However, Pattern.compile doesn't take this regular expression.

Or is there any function that can handle private network IP.

Any thought on that?

Answer 1

It is just a guess but is it possible that you are not escaping \\ in String representing pattern because

Pattern.compile("(^127\\.0\\.0\\.1)|(^10\\.)|(^172\\.1[6-9]\\.)|(^172\\.2[0-9]\\.)|(^172\\.3[0-1]\\.)|(^192\\.168\\.)");

compiles fine for me (although I didn't test it on any data yet).

Update after your edit

I can see that you are using matches method to check if you regex is at start of line. This wont work because matches checks if regex matches entire data. Try changing this method to find

if (!pnm.find()) {
    System.out.println("not match");
}

Answer 2

Use the InetAddress class:

public static void main(String[] args) {
    String[] addrs = {"127.0.0.1", "8.8.8.8", "172.1.2.3", "10.200.34.5", "192.168.111.1", "fc00::1", "www.google.com"};
    for (String a : addrs) {
        try {
            InetAddress ina = InetAddress.getByName(a);
            System.out.printf("Is %s private? %s\n", ina.toString(), ina.isSiteLocalAddress());
        } catch (UnknownHostException e) {
            e.printStackTrace();
        }
    }
}

produces:

Is /127.0.0.1 private? false
Is /8.8.8.8 private? false
Is /172.1.2.3 private? false
Is /10.200.34.5 private? true
Is /192.168.0.1 private? true
Is /fc00:0:0:0:0:0:0:1 private? false
Is www.google.com/173.194.46.20 private? false

Answer 3

You can use following code to find out if the IPAddress is Local or external. This checks for RFC 1918

String ipAddressAr[]    =   
            { "192.168.1.1" , 
              "172.18.20.200",
              "10.1.1.83",
              "127.0.0.1",
              "172.18.20.200"


            };


        String ipAddress    =   null;
        String ipAddressSplit[] =   null;
        int ipAddressIntSplit[] =   {0,0,0,0};

        for (int i = 0; i < ipAddressAr.length; i++) {
            ipAddress = ipAddressAr[i];
            ipAddressSplit = ipAddress.split("\\.");
            ipAddressIntSplit[0]    = Integer.parseInt ( ipAddressSplit[0] );
            ipAddressIntSplit[1]    = Integer.parseInt ( ipAddressSplit[1] );
            ipAddressIntSplit[2]    = Integer.parseInt ( ipAddressSplit[2] );
            ipAddressIntSplit[3]    = Integer.parseInt ( ipAddressSplit[3] );

            /*
             * RFC 1918
             * 
            The Internet Assigned Numbers Authority (IANA) has reserved the
               following three blocks of the IP address space for private internets:

                 10.0.0.0        -   10.255.255.255  (10/8 prefix)
                 172.16.0.0      -   172.31.255.255  (172.16/12 prefix)
                 192.168.0.0     -   192.168.255.255 (192.168/16 prefix)
            */ 
            if ( 
                    ( ipAddressIntSplit[0] == 10 ) ||
                    ( ( ipAddressIntSplit[0] == 172 ) && ( ipAddressIntSplit[1] >= 16 && ipAddressIntSplit[1] <= 31 ) ) ||
                    ( ipAddressIntSplit[0] ==   192  && ipAddressIntSplit[1] == 168  ) ||
                    ( ipAddressIntSplit[0] ==   127  && ipAddressIntSplit[1] == 0 && ipAddressIntSplit[2] == 0  ) 
                    ){
                System.out.println( "IP Address: " + ipAddress + " is Local. ");
            }else{
                System.out.println( "IP Address: " + ipAddress + " is NOT Local. ");
            }
        }