From 369bd0ff9f3313ddf91702cb808bb5fd168a593a Mon Sep 17 00:00:00 2001
From: Anton Keks <anton@codeborne.com>
Date: Tue, 12 Mar 2013 00:24:02 +0200
Subject: [PATCH] make sure MAC is not resolved twice if both MACFetcher and
 MACVendorFetcher are active, but in random order

---
 src/net/azib/ipscan/fetchers/MACFetcher.java     | 16 +++++++++++-----
 src/net/azib/ipscan/fetchers/UnixMACFetcher.java | 11 +++++------
 src/net/azib/ipscan/fetchers/WinMACFetcher.java  |  9 +++++----
 3 files changed, 21 insertions(+), 15 deletions(-)

diff --git a/src/net/azib/ipscan/fetchers/MACFetcher.java b/src/net/azib/ipscan/fetchers/MACFetcher.java
index 0622d614..af5eedfc 100644
--- a/src/net/azib/ipscan/fetchers/MACFetcher.java
+++ b/src/net/azib/ipscan/fetchers/MACFetcher.java
@@ -2,6 +2,7 @@ package net.azib.ipscan.fetchers;
 
 import net.azib.ipscan.core.ScanningSubject;
 
+import java.net.InetAddress;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
@@ -13,6 +14,16 @@ public abstract class MACFetcher extends AbstractFetcher {
 		return ID;
 	}
 
+	@Override
+	public final String scan(ScanningSubject subject) {
+		String mac = (String) subject.getParameter(ID);
+		if (mac == null) mac = resolveMAC(subject.getAddress());
+		subject.setParameter(ID, mac);
+		return mac;
+	}
+
+	protected abstract String resolveMAC(InetAddress address);
+
 	static String bytesToMAC(byte[] bytes) {
 		StringBuilder mac = new StringBuilder();
 		for (byte b : bytes) mac.append(String.format("%02X", b)).append(":");
@@ -24,9 +35,4 @@ public abstract class MACFetcher extends AbstractFetcher {
 		Matcher m = macAddressPattern.matcher(line);
 		return m.find() ? m.group().toUpperCase() : null;
 	}
-
-	String remember(String mac, ScanningSubject subject) {
-		subject.setParameter(ID, mac);
-		return mac;
-	}
 }
diff --git a/src/net/azib/ipscan/fetchers/UnixMACFetcher.java b/src/net/azib/ipscan/fetchers/UnixMACFetcher.java
index 778c4ba0..445f14d0 100644
--- a/src/net/azib/ipscan/fetchers/UnixMACFetcher.java
+++ b/src/net/azib/ipscan/fetchers/UnixMACFetcher.java
@@ -1,6 +1,5 @@
 package net.azib.ipscan.fetchers;
 
-import net.azib.ipscan.core.ScanningSubject;
 import net.azib.ipscan.util.IOUtils;
 
 import java.io.BufferedReader;
@@ -13,8 +12,8 @@ public class UnixMACFetcher extends MACFetcher {
 	@Override public void init() {
 	}
 
-	@Override public String scan(ScanningSubject subject) {
-		String ip = subject.getAddress().getHostAddress();
+	@Override public String resolveMAC(InetAddress address) {
+		String ip = address.getHostAddress();
 		BufferedReader reader = null;
 		try {
 			// highly inefficient implementation, there must be a better way (using JNA?)
@@ -23,7 +22,7 @@ public class UnixMACFetcher extends MACFetcher {
 			String line;
 			while ((line = reader.readLine()) != null) {
 				if (line.contains(ip))
-					return remember(extractMAC(line), subject);
+					return extractMAC(line);
 			}
 
 			// see if it is a local address
@@ -34,8 +33,8 @@ public class UnixMACFetcher extends MACFetcher {
 					Enumeration<InetAddress> addrs = netif.getInetAddresses();
 					while (addrs.hasMoreElements()) {
 						InetAddress addr = addrs.nextElement();
-						if (addr.equals(subject.getAddress()))
-							return remember(bytesToMAC(netif.getHardwareAddress()), subject);
+						if (addr.equals(address))
+							return bytesToMAC(netif.getHardwareAddress());
 					}
 				}
 			}
diff --git a/src/net/azib/ipscan/fetchers/WinMACFetcher.java b/src/net/azib/ipscan/fetchers/WinMACFetcher.java
index 5eb8a787..a5dc9e35 100644
--- a/src/net/azib/ipscan/fetchers/WinMACFetcher.java
+++ b/src/net/azib/ipscan/fetchers/WinMACFetcher.java
@@ -2,10 +2,11 @@ package net.azib.ipscan.fetchers;
 
 import com.sun.jna.Memory;
 import com.sun.jna.Pointer;
-import net.azib.ipscan.core.ScanningSubject;
 import net.azib.ipscan.core.net.WinIpHlpDll;
 import net.azib.ipscan.core.net.WinIpHlpDll.IpAddrByVal;
 
+import java.net.InetAddress;
+
 public class WinMACFetcher extends MACFetcher {
 	private WinIpHlpDll dll;
 
@@ -13,9 +14,9 @@ public class WinMACFetcher extends MACFetcher {
 		dll = WinIpHlpDll.Loader.load();
 	}
 
-	@Override public String scan(ScanningSubject subject) {
+	@Override public String resolveMAC(InetAddress address) {
 		IpAddrByVal destIP = new IpAddrByVal();
-		destIP.bytes = subject.getAddress().getAddress();
+		destIP.bytes = address.getAddress();
 
 		Pointer pmac = new Memory(8);
 		Pointer plen = new Memory(4);
@@ -26,6 +27,6 @@ public class WinMACFetcher extends MACFetcher {
 		if (result != 0) return null;
 
 		byte[] bytes = pmac.getByteArray(0, plen.getInt(0));
-		return remember(bytesToMAC(bytes), subject);
+		return bytesToMAC(bytes);
 	}
 }