Refactor Additional header for netconf hello message.

[controller.git] / opendaylight / netconf / netconf-util / src / main / java / org / opendaylight / controller / netconf / util / handler / NetconfXMLToHelloMessageDecoder.java

diff --git a/opendaylight/netconf/netconf-util/src/main/java/org/opendaylight/controller/netconf/util/handler/NetconfXMLToHelloMessageDecoder.java b/opendaylight/netconf/netconf-util/src/main/java/org/opendaylight/controller/netconf/util/handler/NetconfXMLToHelloMessageDecoder.java
new file mode 100644 (file)
index 0000000..42586a5
--- /dev/null
+++ b/opendaylight/netconf/netconf-util/src/main/java/org/opendaylight/controller/netconf/util/handler/NetconfXMLToHelloMessageDecoder.java
@@ -0,0 +1,124 @@
+/*
+ * Copyright (c) 2014 Cisco Systems, Inc. and others.  All rights reserved.
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License v1.0 which accompanies this distribution,
+ * and is available at http://www.eclipse.org/legal/epl-v10.html
+ */
+package org.opendaylight.controller.netconf.util.handler;
+
+import java.nio.ByteBuffer;
+import java.util.Arrays;
+import java.util.List;
+
+import org.opendaylight.controller.netconf.api.NetconfMessage;
+import org.opendaylight.controller.netconf.util.messages.NetconfHelloMessage;
+import org.opendaylight.controller.netconf.util.messages.NetconfHelloMessageAdditionalHeader;
+import org.w3c.dom.Document;
+
+import com.google.common.base.Charsets;
+import com.google.common.collect.ImmutableList;
+
+/**
+ * Customized NetconfXMLToMessageDecoder that reads additional header with
+ * session metadata from
+ * {@link org.opendaylight.controller.netconf.util.messages.NetconfHelloMessage}
+ * . Used by netconf server to retrieve information about session metadata.
+ */
+public class NetconfXMLToHelloMessageDecoder extends NetconfXMLToMessageDecoder {
+
+    private static final List<byte[]> POSSIBLE_ENDS = ImmutableList.of(
+            new byte[] { ']', '\n' },
+            new byte[] { ']', '\r', '\n' });
+    private static final List<byte[]> POSSIBLE_STARTS = ImmutableList.of(
+            new byte[] { '[' },
+            new byte[] { '\r', '\n', '[' },
+            new byte[] { '\n', '[' });
+
+    private String additionalHeaderCache;
+
+    @Override
+    protected byte[] preprocessMessageBytes(byte[] bytes) {
+        // Extract bytes containing header with additional metadata
+
+        if (startsWithAdditionalHeader(bytes)) {
+            // Auth information containing username, ip address... extracted for monitoring
+            int endOfAuthHeader = getAdditionalHeaderEndIndex(bytes);
+            if (endOfAuthHeader > -1) {
+                byte[] additionalHeaderBytes = Arrays.copyOfRange(bytes, 0, endOfAuthHeader + 2);
+                additionalHeaderCache = additionalHeaderToString(additionalHeaderBytes);
+                bytes = Arrays.copyOfRange(bytes, endOfAuthHeader + 2, bytes.length);
+            }
+        }
+
+        return bytes;
+    }
+
+    @Override
+    protected void cleanUpAfterDecode() {
+        additionalHeaderCache = null;
+    }
+
+    @Override
+    protected NetconfMessage buildNetconfMessage(Document doc) {
+        return new NetconfHelloMessage(doc, additionalHeaderCache == null ? null
+                : NetconfHelloMessageAdditionalHeader.fromString(additionalHeaderCache));
+    }
+
+    private int getAdditionalHeaderEndIndex(byte[] bytes) {
+        for (byte[] possibleEnd : POSSIBLE_ENDS) {
+            int idx = findByteSequence(bytes, possibleEnd);
+
+            if (idx != -1) {
+                return idx;
+            }
+        }
+
+        return -1;
+    }
+
+    private static int findByteSequence(final byte[] bytes, final byte[] sequence) {
+        if (bytes.length < sequence.length) {
+            throw new IllegalArgumentException("Sequence to be found is longer than the given byte array.");
+        }
+        if (bytes.length == sequence.length) {
+            if (Arrays.equals(bytes, sequence)) {
+                return 0;
+            } else {
+                return -1;
+            }
+        }
+        int j = 0;
+        for (int i = 0; i < bytes.length; i++) {
+            if (bytes[i] == sequence[j]) {
+                j++;
+                if (j == sequence.length) {
+                    return i - j + 1;
+                }
+            } else {
+                j = 0;
+            }
+        }
+        return -1;
+    }
+
+    private boolean startsWithAdditionalHeader(byte[] bytes) {
+        for (byte[] possibleStart : POSSIBLE_STARTS) {
+            int i = 0;
+            for (byte b : possibleStart) {
+                if(bytes[i++] != b)
+                    break;
+
+                if(i == possibleStart.length)
+                    return true;
+            }
+        }
+
+        return false;
+    }
+
+    private String additionalHeaderToString(byte[] bytes) {
+        return Charsets.UTF_8.decode(ByteBuffer.wrap(bytes)).toString();
+    }
+
+}