Author: sebb
Date: Thu Mar 2 22:34:35 2017
New Revision: 1785208
URL: http://svn.apache.org/viewvc?rev=1785208&view=rev
Log:
NET-619 SubnetUtils - improve binary netmask algorithm
This fixes #6
Modified:
commons/proper/net/trunk/src/changes/changes.xml
commons/proper/net/trunk/src/main/java/org/apache/commons/net/util/SubnetUtils.java
Modified: commons/proper/net/trunk/src/changes/changes.xml
URL:
http://svn.apache.org/viewvc/commons/proper/net/trunk/src/changes/changes.xml?rev=1785208&r1=1785207&r2=1785208&view=diff
==============================================================================
--- commons/proper/net/trunk/src/changes/changes.xml [utf-8] (original)
+++ commons/proper/net/trunk/src/changes/changes.xml [utf-8] Thu Mar 2
22:34:35 2017
@@ -71,6 +71,9 @@ This is mainly a bug-fix release. See fu
However it is not source compatible with releases before 3.4, as some methods
were added to the interface NtpV3Packet in 3.4
">
+ <action issue="NET-619" type="fix" dev="sebb" due-to="Makoto
Sakaguchi">
+ SubnetUtils - improve binary netmask algorithm
+ </action>
<action issue="NET-613" type="fix" dev="sebb" due-to="Donald
Kwakkel">
System Information Leak in ftp parser
</action>
Modified:
commons/proper/net/trunk/src/main/java/org/apache/commons/net/util/SubnetUtils.java
URL:
http://svn.apache.org/viewvc/commons/proper/net/trunk/src/main/java/org/apache/commons/net/util/SubnetUtils.java?rev=1785208&r1=1785207&r2=1785208&view=diff
==============================================================================
---
commons/proper/net/trunk/src/main/java/org/apache/commons/net/util/SubnetUtils.java
(original)
+++
commons/proper/net/trunk/src/main/java/org/apache/commons/net/util/SubnetUtils.java
Thu Mar 2 22:34:35 2017
@@ -261,10 +261,17 @@ public class SubnetUtils {
address = matchAddress(matcher);
/* Create a binary netmask from the number of bits specification
/x */
- int cidrPart = rangeCheck(Integer.parseInt(matcher.group(5)), 0,
NBITS);
- for (int j = 0; j < cidrPart; ++j) {
- netmask |= (1 << 31 - j);
- }
+
+ int trailingZeroes = NBITS -
rangeCheck(Integer.parseInt(matcher.group(5)), 0, NBITS);
+ /*
+ * An IPv4 netmask consists of 32 bits, a contiguous sequence
+ * of the specified number of ones followed by all zeros.
+ * So, it can be obtained by shifting an unsigned integer (32
bits) to the left by
+ * the number of trailing zeros which is (32 - the # bits
specification).
+ * Note that there is no unsigned left shift operator, so we have
to use
+ * a long to ensure that the left-most bit is shifted out
correctly.
+ */
+ netmask = (int) (0x0FFFFFFFFL << trailingZeroes );
/* Calculate base network address */
network = (address & netmask);
