Attachment 27686 Details for Bug 51953 – Netmask class

[patch] Netmask class

0001-Netmask-filtering-NetMask-class.patch (text/plain), 3.91 KB, created by Francis Galiegue on 2011-10-04 18:06:15 UTC

(hide)

Description:

Filename:

MIME Type:

Creator: Francis Galiegue

Created: 2011-10-04 18:06:15 UTC

Size: 3.91 KB

patch

obsolete

>From 379f36c26c0ab3872c5ab6594cadb83533dd8c66 Mon Sep 17 00:00:00 2001
>From: Francis Galiegue <fgaliegue@gmail.com>
>Date: Tue, 4 Oct 2011 19:57:24 +0200
>Subject: [PATCH 1/3] Netmask filtering: NetMask class
>
>---
> java/org/apache/catalina/util/NetMask.java |  103 ++++++++++++++++++++++++++++
> 1 files changed, 103 insertions(+), 0 deletions(-)
> create mode 100644 java/org/apache/catalina/util/NetMask.java
>
>diff --git a/java/org/apache/catalina/util/NetMask.java b/java/org/apache/catalina/util/NetMask.java
>new file mode 100644
>index 0000000..b834443
>--- /dev/null
>+++ b/java/org/apache/catalina/util/NetMask.java
>@@ -0,0 +1,103 @@
>+package org.apache.catalina.util;
>+
>+import java.math.BigInteger;
>+import java.net.InetAddress;
>+import java.net.UnknownHostException;
>+
>+/**
>+ * A class representing a netmask, which is at the core of this valve.
>+ *
>+ * <p>The constructor takes a {@link java.lang.String} representing a
>+ * CIDR netmask as an argument and extracts two informations from it: the
>+ * network address and the CIDR. It then turns the address into a {@link
>+ * java.math.BigInteger}, calculates the right shift and shifts that
>+ * BigInteger by it.</p>
>+ * <p>The process to verify whether an IP address falls within the mask
>+ * is to also convert it to a BigInteger, shifting it right and comparing
>+ * it to the stored BigInteger.
>+ * </p>
>+ */
>+
>+public final class NetMask {
>+    /**
>+     * The argument to the constructor, used for .toString()
>+     */
>+    private final String expression;
>+
>+    /**
>+     * The number of bits a matching candidate needs to be shifted right
>+     * in order to see if it matches
>+     */
>+    private final int shift;
>+
>+    /**
>+     * The network address, already shifted right
>+     */
>+    private final BigInteger mask;
>+
>+    /**
>+     * Constructor.
>+     *
>+     * @param expression the CIDR netmask
>+     * @throws IllegalArgumentException if the netmask is not correct
>+     * (invalid address specification, malformed CIDR prefix, etc)
>+     */
>+    public NetMask(final String expression) {
>+        final int idx = expression.indexOf("/");
>+        final int cidr, addrlen;
>+        final String addressPart;
>+        final InetAddress addr;
>+        final byte[] bytes;
>+
>+        if (idx == -1) {
>+            cidr = -1;
>+            addressPart = expression;
>+        } else {
>+            final String substring = expression.substring(idx + 1);
>+            try {
>+                cidr = Integer.parseInt(substring);
>+                if (cidr < 0)
>+                    throw new NumberFormatException("CIDR is negative");
>+            } catch (NumberFormatException ignored) {
>+                throw new IllegalArgumentException("provided CIDR mask ("
>+                    + substring + ") is invalid");
>+            }
>+            addressPart = expression.substring(0, idx);
>+        }
>+
>+        try {
>+            addr = InetAddress.getByName(addressPart);
>+        } catch (UnknownHostException e) {
>+            throw new IllegalArgumentException("provided address ("
>+                + addressPart + ") is invalid");
>+        }
>+
>+        bytes = addr.getAddress();
>+        addrlen = bytes.length * 8;
>+        shift = cidr == -1 ? 0 : addrlen - cidr;
>+
>+        if (shift < 0)
>+            throw new IllegalArgumentException("CIDR prefix (" + cidr
>+                + ") is greater than address length (" + addrlen + ")");
>+        mask = new BigInteger(bytes).shiftRight(shift);
>+        this.expression = expression;
>+    }
>+
>+    /**
>+     * Test if a given address matches this netmask
>+     *
>+     * @param addr The {@link java.net.InetAddress} to test
>+     * @return true on match, false otherwise
>+     */
>+    public boolean matches (final InetAddress addr) {
>+        final BigInteger provided = new BigInteger(addr.getAddress())
>+            .shiftRight(shift);
>+
>+        return mask.equals(provided);
>+    }
>+
>+    @Override
>+    public String toString() {
>+        return expression;
>+    }
>+}
>-- 
>1.7.6
>

Actions: View | Diff

Attachments on bug 51953: 27686 | 27687 | 27688 | 27689 | 27691 | 27694 | 27726 | 27782