com.maxmind.db.Network Maven / Gradle / Ivy
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package com.maxmind.db;
import java.net.InetAddress;
import java.net.UnknownHostException;
/**
* Network represents an IP network.
*/
public final class Network {
private final InetAddress ipAddress;
private final int prefixLength;
private InetAddress networkAddress = null;
/**
* Construct a Network
*
* @param ipAddress An IP address in the network. This does not have to be
* the first address in the network.
* @param prefixLength The prefix length for the network.
*/
public Network(InetAddress ipAddress, int prefixLength) {
this.ipAddress = ipAddress;
this.prefixLength = prefixLength;
}
/**
* @return The first address in the network.
*/
public InetAddress getNetworkAddress() {
if (networkAddress != null) {
return networkAddress;
}
byte[] ipBytes = ipAddress.getAddress();
byte[] networkBytes = new byte[ipBytes.length];
int curPrefix = prefixLength;
for (int i = 0; i < ipBytes.length && curPrefix > 0; i++) {
byte b = ipBytes[i];
if (curPrefix < 8) {
int shiftN = 8 - curPrefix;
b = (byte) ((b >> shiftN) << shiftN);
}
networkBytes[i] = b;
curPrefix -= 8;
}
try {
networkAddress = InetAddress.getByAddress(networkBytes);
} catch (UnknownHostException e) {
throw new RuntimeException(
"Illegal network address byte length of " + networkBytes.length);
}
return networkAddress;
}
/**
* @return The prefix length is the number of leading 1 bits in the subnet
* mask. Sometimes also known as netmask length.
*/
public int getPrefixLength() {
return prefixLength;
}
/**
* @return A string representation of the network in CIDR notation, e.g.,
* 1.2.3.0/24 or 2001::/8.
*/
public String toString() {
return getNetworkAddress().getHostAddress() + "/" + prefixLength;
}
}