Package org.apache.catalina.util

Class NetMask

  • public final class NetMask
extends java.lang.Object
    A class representing a CIDR netmask.

    The constructor takes a string as an argument which represents a netmask, as per the CIDR notation -- whether this netmask be IPv4 or IPv6. It then extracts the network address (before the /) and the CIDR prefix (after the /), and tells through the #matches() method whether a candidate InetAddress object fits in the recorded range.

    As byte arrays as returned by InetAddress.getByName() are always in network byte order, finding a match is therefore as simple as testing whether the n first bits (where n is the CIDR) are the same in both byte arrays (the one of the network address and the one of the candidate address). We do that by first doing byte comparisons, then testing the last bits if any (that is, if the remainder of the integer division of the CIDR by 8 is not 0).

    As a bonus, if no '/' is found in the input, it is assumed that an exact address match is required.

    • Constructor Summary

      Constructors 
      Constructor Description
      NetMask​(java.lang.String input)
      Constructor

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      boolean equals​(java.lang.Object o)  
      int hashCode()  
      boolean matches​(java.net.InetAddress addr)
      Test if a given address matches this netmask.
      boolean matches​(java.net.InetAddress addr, boolean checkedPort)
      Test if a given address matches this netmask.
      boolean matches​(java.net.InetAddress addr, int port)
      Test if a given address and port matches this netmask.
      java.lang.String toString()  

      • Methods inherited from class java.lang.Object

        clone, finalize, getClass, notify, notifyAll, wait, wait, wait

    • Constructor Detail

      • NetMask

        public NetMask​(java.lang.String input)
        Constructor
        Parameters:
        input - the CIDR netmask
        Throws:
        java.lang.IllegalArgumentException - if the netmask is not correct (invalid address specification, malformed CIDR prefix, etc)

    • Method Detail

      • matches

        public boolean matches​(java.net.InetAddress addr,
                       int port)
        Test if a given address and port matches this netmask.
        Parameters:
        addr - The InetAddress to test
        port - The port to test
        Returns:
        true on match, false otherwise

      • matches

        public boolean matches​(java.net.InetAddress addr)
        Test if a given address matches this netmask.
        Parameters:
        addr - The InetAddress to test
        Returns:
        true on match, false otherwise

      • matches

        public boolean matches​(java.net.InetAddress addr,
                       boolean checkedPort)
        Test if a given address matches this netmask.
        Parameters:
        addr - The InetAddress to test
        checkedPort - Indicates, whether we already checked the port
        Returns:
        true on match, false otherwise

      • toString

        public java.lang.String toString()
        Overrides:
        toString in class java.lang.Object

      • equals

        public boolean equals​(java.lang.Object o)
        Overrides:
        equals in class java.lang.Object

      • hashCode

        public int hashCode()
        Overrides:
        hashCode in class java.lang.Object