1 files changed, 83 insertions, 0 deletions
diff --git a/src/main/java/com/btr/proxy/selector/whitelist/IpRangeFilter.java b/src/main/java/com/btr/proxy/selector/whitelist/IpRangeFilter.java
new file mode 100644
index 0000000..293f520
--- /dev/null
+++ b/src/main/java/com/btr/proxy/selector/whitelist/IpRangeFilter.java
@@ -0,0 +1,83 @@
+package com.btr.proxy.selector.whitelist;
+
+import java.net.InetAddress;
+import java.net.URI;
+import java.net.UnknownHostException;
+
+import com.btr.proxy.util.UriFilter;
+
+/*****************************************************************************
+ * Filters an URI by inspecting it's IP address is in a given range. 
+ * The range  as must be defined in CIDR notation.
+ * e.g. 192.0.2.1/24,
+ *
+ * @author Bernd Rosstauscher (proxyvole@rosstauscher.de) Copyright 2009
+ ****************************************************************************/
+
+public class IpRangeFilter implements UriFilter {
+
+	private byte[] matchTo;
+	int numOfBits;
+
+	/*************************************************************************
+	 * Constructor
+	 * @param matchTo the match subnet in CIDR notation.
+	 ************************************************************************/
+	
+	public IpRangeFilter(String matchTo) {
+		super();
+		
+		String[] parts = matchTo.split("/");
+		if (parts.length != 2) {
+			throw new IllegalArgumentException("IP range is not valid:"+matchTo);
+		}
+		
+		try {
+			InetAddress address = InetAddress.getByName(parts[0].trim());
+			this.matchTo = address.getAddress();
+		} catch (UnknownHostException e) {
+			throw new IllegalArgumentException("IP range is not valid:"+matchTo);
+		}
+		
+		this.numOfBits = Integer.parseInt(parts[1].trim());
+	}
+	
+	/*************************************************************************
+	 * accept
+	 * @see com.btr.proxy.util.UriFilter#accept(java.net.URI)
+	 ************************************************************************/
+
+	public boolean accept(URI uri) {
+		if (uri == null || uri.getHost() == null) {
+			return false;
+		}
+		try {
+			InetAddress address = InetAddress.getByName(uri.getHost());
+			byte[] addr = address.getAddress();
+			
+			// Comparing IP6 against IP4?
+			if (addr.length != this.matchTo.length) {
+				return false;
+			}
+
+			int bit = 0;
+			for (int nibble = 0; nibble < addr.length; nibble++) {
+				for (int nibblePos = 7; nibblePos >= 0; nibblePos--) {
+					int mask = 1 << nibblePos;
+					if ((this.matchTo[nibble] & mask) != (addr[nibble] & mask)) {
+						return false;
+					}
+					bit++;
+					if (bit >= this.numOfBits) {
+						return true;
+					}
+				}
+			}
+			
+		} catch (UnknownHostException e) {
+			// In this case we can not get the IP do not match.
+		}
+		return false;
+	}
+
+}