Handle IP fragments and packet parsing errors

src/main/java/net/floodlightcontroller/packet/BasePacket.java

@@ -17,12 +17,16 @@
 
 package net.floodlightcontroller.packet;
 
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
 
 /**
 *
 * @author David Erickson (daviderickson@cs.stanford.edu)
 */
 public abstract class BasePacket implements IPacket {
+    public static final Logger log = LoggerFactory.getLogger(BasePacket.class);
     protected IPacket parent;
     protected IPacket payload;
 
@@ -113,4 +117,4 @@ public abstract class BasePacket implements IPacket {
         pkt.setParent(this.parent);
         return pkt;
     }
-}
\ No newline at end of file
+}

src/main/java/net/floodlightcontroller/packet/Ethernet.java

@@ -22,6 +22,7 @@ import java.util.Arrays;
 import java.util.HashMap;
 import java.util.Map;
 
+import net.floodlightcontroller.core.annotations.LogMessageDoc;
 import net.floodlightcontroller.util.MACAddress;
 import org.openflow.util.HexString;
 
@@ -228,9 +229,15 @@ public class Ethernet extends BasePacket {
         return data;
     }
 
+    @LogMessageDoc(level="INFO",
+            message="Failed to parse ethernet packet payload",
+            explanation="Was unable to parse ethernet payload, often caused " +
+                    "by packet truncation. Packet is forwarded as a plain " +
+                    "ethernet packet.",
+            recommendation=LogMessageDoc.GENERIC_ACTION)
     @Override
     public IPacket deserialize(byte[] data, int offset, int length) {
-        if (length <= 0)
+        if (length <= 16)  // Ethernet packet minium should be 60, this is reasonable
             return null;
         ByteBuffer bb = ByteBuffer.wrap(data, offset, length);
         if (this.destinationMACAddress == null)
@@ -261,13 +268,22 @@ public class Ethernet extends BasePacket {
             Class<? extends IPacket> clazz = Ethernet.etherTypeClassMap.get(this.etherType);
             try {
                 payload = clazz.newInstance();
+                this.payload = payload.deserialize(data, bb.position(), bb.limit()-bb.position());
             } catch (Exception e) {
-                throw new RuntimeException("Error parsing payload for Ethernet packet", e);
+                log.info("Failed to parse ethernet packet {}->{} payload as {}," +
+                         " treat as plain ethernet packet",
+                         new Object[] {this.sourceMACAddress, this.destinationMACAddress,
+                                       clazz.getClass().getName()});
+                if (log.isDebugEnabled()) {
+                    log.debug("Exception from parsing {}", e);
+                }
+                payload = new Data();
+                this.payload = payload.deserialize(data, bb.position(), bb.limit()-bb.position());
             }
         } else {
             payload = new Data();
+            this.payload = payload.deserialize(data, bb.position(), bb.limit()-bb.position());
         }
-        this.payload = payload.deserialize(data, bb.position(), bb.limit()-bb.position());
         this.payload.setParent(this);
         return this;
     }

src/main/java/net/floodlightcontroller/packet/IPv4.java

@@ -26,6 +26,8 @@ import java.util.Collection;
 import java.util.HashMap;
 import java.util.Map;
 
+import net.floodlightcontroller.core.annotations.LogMessageDoc;
+
 /**
  * @author David Erickson (daviderickson@cs.stanford.edu)
  *
@@ -334,6 +336,11 @@ public class IPv4 extends BasePacket {
         return data;
     }
 
+    @LogMessageDoc(level="INFO",
+            message="IP fragment detected",
+            explanation="Packet in is an IP fragment. Controller forwards " +
+                    "it using IP header only. Transport headers are ignored.",
+            recommendation=LogMessageDoc.GENERIC_ACTION)
     @Override
     public IPacket deserialize(byte[] data, int offset, int length) {
         ByteBuffer bb = ByteBuffer.wrap(data, offset, length);
@@ -361,7 +368,8 @@ public class IPv4 extends BasePacket {
         }
 
         IPacket payload;
-        if (IPv4.protocolClassMap.containsKey(this.protocol)) {
+        boolean is_frag = ((this.flags & 0x1) != 0) || (this.fragmentOffset != 0);
+        if (!is_frag && IPv4.protocolClassMap.containsKey(this.protocol)) {
             Class<? extends IPacket> clazz = IPv4.protocolClassMap.get(this.protocol);
             try {
                 payload = clazz.newInstance();
@@ -369,6 +377,11 @@ public class IPv4 extends BasePacket {
                 throw new RuntimeException("Error parsing payload for IPv4 packet", e);
             }
         } else {
+            if (is_frag) {
+                log.info("IPv4 fragment detected {}->{}, forward using IP header only",
+                        fromIPv4Address(this.sourceAddress),
+                        fromIPv4Address(this.destinationAddress));
+            }
             payload = new Data();
         }
         int payloadLength = this.totalLength - this.headerLength * 4;
@@ -493,7 +506,7 @@ public class IPv4 extends BasePacket {
      * @return The IP address separated into bytes.
      */
     public static byte[] toIPv4AddressBytes(int ipAddress) {
-    	return new byte[] {
+        return new byte[] {
                 (byte)(ipAddress >>> 24),
                 (byte)(ipAddress >>> 16),
                 (byte)(ipAddress >>> 8),