Fixed bug with IP address identification

.gitignore

@@ -1 +1,2 @@
-/target/
+/target/
+/nbproject/

src/main/java/com/offbynull/portmapper/common/RegexUtils.java

@@ -28,10 +28,20 @@
  */
 public final class RegexUtils {
     /**
-     * IPV4 Regex. Taken from http://stackoverflow.com/questions/106179/regular-expression-to-match-hostname-or-ip-address.
+     * Semi-IPV4 Regex. Groups 1 to 4 are the individual address components. Further checking needs to be done to
+     * ensure that each component is between 0 to 255 and that there are no trailing zeros.
+     * 
+     * This isn't being done in the regex due to complexity.
      */
     private static final Pattern IPV4_PATTERN = Pattern.compile(
-            "(([0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])\\.){3}([0-9]|[1-9][0-9]|1[0-9‌​]{2}|2[0-4][0-9]|25[0-5])");
+            "([0-9]{1,3})\\."
+            + "([0-9]{1,3})\\."
+            + "([0-9]{1,3})\\."
+            + "([0-9]{1,3})");
+
+    private static final int IPV4_COMPONENT_COUNT = 4;
+
+    private static final int IPV4_COMPONENT_MAX = 255;
 
     private RegexUtils() {
         // do nothing
@@ -49,7 +59,24 @@ public static List<String> findAllIpv4Addresses(String text) {
         List<String> ret = new LinkedList<>();
 
         Matcher matcher = IPV4_PATTERN.matcher(text);
+        top:
         while (matcher.find()) {
+            for (int i = 1; i <= IPV4_COMPONENT_COUNT; i++) {
+                String componentStr = matcher.group(i);
+                int component = Integer.parseInt(componentStr);
+
+                // Fail if component has trailing zeros
+                if (!String.valueOf(component).equals(componentStr)) {
+                    continue top;
+                }
+
+                // Fail if component is greater than 255. The regex ensures that it's never below 0.
+                if (component > IPV4_COMPONENT_MAX) {
+                    continue top;
+                }
+            }
+
+            // IP is valid, add it to the return list
             ret.add(matcher.group(0));
         }
 

src/test/java/com/offbynull/portmapper/common/RegexUtilsTest.java

@@ -0,0 +1,46 @@
+package com.offbynull.portmapper.common;
+
+import java.util.List;
+import org.junit.Assert;
+import org.junit.Test;
+
+public class RegexUtilsTest {
+
+    @Test
+    public void mustPassOnProperAddressesWithFullComponents() {
+        List<String> addresses = RegexUtils.findAllIpv4Addresses(
+                "sf sdf sd 212.123.222.199 fs\n\n \r\tfsf123.124.125.126sdfsfsdfs");
+
+        Assert.assertEquals(2, addresses.size());
+        Assert.assertEquals("212.123.222.199", addresses.get(0));
+        Assert.assertEquals("123.124.125.126", addresses.get(1));
+    }
+
+    @Test
+    public void mustPassOnProperAddressesWithNonFullComponents() {
+        List<String> addresses = RegexUtils.findAllIpv4Addresses(
+                "sf sdf sd 10.6.0.254 fs\n\n \r\tfsf10.6.0.2sdfsfsdfs");
+
+        Assert.assertEquals(2, addresses.size());
+        Assert.assertEquals("10.6.0.254", addresses.get(0));
+        Assert.assertEquals("10.6.0.2", addresses.get(1));
+    }
+
+    @Test
+    public void mustRejectComponentsWithTrailingZeros() {
+        List<String> addresses = RegexUtils.findAllIpv4Addresses(
+                "sf sdf sd 010.6.0.254 fs\n\n \r\tfsf10.6.0.2sdfsfsdfs");
+
+        Assert.assertEquals(1, addresses.size());
+        Assert.assertEquals("10.6.0.2", addresses.get(0));
+    }
+
+    @Test
+    public void mustRejectComponentsThatExceed255() {
+        List<String> addresses = RegexUtils.findAllIpv4Addresses(
+                "sf sdf sd 10.6.0.256 fs\n\n \r\tfsf10.6.0.2sdfsfsdfs");
+
+        Assert.assertEquals(1, addresses.size());
+        Assert.assertEquals("10.6.0.2", addresses.get(0));
+    }
+}