From f6113a50009aff9dcb28bc1df522901a7c15a101 Mon Sep 17 00:00:00 2001
From: Damian Minkov <damencho@jitsi.org>
Date: Thu, 17 Dec 2009 16:58:51 +0000
Subject: [PATCH] Add padding when creating extension header and remove
 extensions after process the sound levels coming from the focus.

---
 .../neomedia/RTPConnectorInputStream.java     |  1 -
 .../communicator/impl/neomedia/RawPacket.java | 20 +++++++++++++++++++
 .../transform/csrc/CsrcTransformEngine.java   | 12 ++++++++++-
 .../transform/srtp/SRTPCryptoContext.java     | 20 +++++++++++--------
 4 files changed, 43 insertions(+), 10 deletions(-)

diff --git a/src/net/java/sip/communicator/impl/neomedia/RTPConnectorInputStream.java b/src/net/java/sip/communicator/impl/neomedia/RTPConnectorInputStream.java
index 714a14421..f8f2f696b 100755
--- a/src/net/java/sip/communicator/impl/neomedia/RTPConnectorInputStream.java
+++ b/src/net/java/sip/communicator/impl/neomedia/RTPConnectorInputStream.java
@@ -10,7 +10,6 @@
 import java.net.*;
 
 import javax.media.protocol.*;
-import javax.media.rtp.*;
 
 /**
  * @author Bing SU (nova.su@gmail.com)
diff --git a/src/net/java/sip/communicator/impl/neomedia/RawPacket.java b/src/net/java/sip/communicator/impl/neomedia/RawPacket.java
index d1a787cb2..7ec773f99 100755
--- a/src/net/java/sip/communicator/impl/neomedia/RawPacket.java
+++ b/src/net/java/sip/communicator/impl/neomedia/RawPacket.java
@@ -587,6 +587,26 @@ public void addExtension(byte[] extBuff, int newExtensionLen)
         this.length = newBuffLen - offset;
     }
 
+    /**
+     * Removes the extension from the packet and its header.
+     */
+    public void removeExtension()
+    {
+        if(!getExtensionBit())
+            return;
+
+        int payloadOffset = offset + getHeaderLength();
+
+        int extHeaderLen = getExtensionLength() + EXT_HEADER_SIZE;
+
+        System.arraycopy(buffer, payloadOffset,
+            buffer, payloadOffset - extHeaderLen, getPayloadLength());
+
+        this.length -= extHeaderLen;
+
+        setExtensionBit(false);
+    }
+
     /**
      * Returns a bi-dimensional byte array containing a map binding CSRC IDs to
      * audio levels as reported by the remote party that sent this packet.
diff --git a/src/net/java/sip/communicator/impl/neomedia/transform/csrc/CsrcTransformEngine.java b/src/net/java/sip/communicator/impl/neomedia/transform/csrc/CsrcTransformEngine.java
index 61838de26..11959d78c 100644
--- a/src/net/java/sip/communicator/impl/neomedia/transform/csrc/CsrcTransformEngine.java
+++ b/src/net/java/sip/communicator/impl/neomedia/transform/csrc/CsrcTransformEngine.java
@@ -120,6 +120,8 @@ public RawPacket reverseTransform(RawPacket pkt)
 
                 csrcLevelDispatcher.addLevels(levels);
             }
+
+            pkt.removeExtension();
         }
         return pkt;
     }
@@ -161,7 +163,6 @@ public synchronized RawPacket transform(RawPacket pkt)
             byte[] levelsExt = createLevelExtensionBuffer(csrcList);
 
             pkt.addExtension(levelsExt, extensionBuffLen);
-
         }
 
         return pkt;
@@ -208,6 +209,15 @@ private byte[] createLevelExtensionBuffer(long[] csrcList)
     {
         int buffLen = 1 + //CSRC one byte extension hdr
                       csrcList.length;
+
+        // calculate extension padding
+        int padLen = 4 - buffLen%4;
+
+        if(padLen == 4)
+            padLen = 0;
+
+        buffLen += padLen;
+
         byte[] extensionBuff = getExtensionBuff(buffLen);
 
         extensionBuff[0] =
diff --git a/src/net/java/sip/communicator/impl/neomedia/transform/srtp/SRTPCryptoContext.java b/src/net/java/sip/communicator/impl/neomedia/transform/srtp/SRTPCryptoContext.java
index dc2f0fb0c..5e7b7cc58 100644
--- a/src/net/java/sip/communicator/impl/neomedia/transform/srtp/SRTPCryptoContext.java
+++ b/src/net/java/sip/communicator/impl/neomedia/transform/srtp/SRTPCryptoContext.java
@@ -347,26 +347,30 @@ public void setROC(int rocIn) {
      *
      * @param pkt the RTP packet that is going to be sent out
      */
-    public void transformPacket(RawPacket pkt) {
+    public void transformPacket(RawPacket pkt)
+    {
         /* Encrypt the packet using Counter Mode encryption */
-        if (policy.getEncType() == SRTPPolicy.AESCM_ENCRYPTION) {
+        if (policy.getEncType() == SRTPPolicy.AESCM_ENCRYPTION)
+        {
             processPacketAESCM(pkt);
         }
-
-        /* Encrypt the packet using F8 Mode encryption */
-        else if (policy.getEncType() == SRTPPolicy.AESF8_ENCRYPTION) {
+        else if (policy.getEncType() == SRTPPolicy.AESF8_ENCRYPTION) 
+        {
+            /* Encrypt the packet using F8 Mode encryption */
             processPacketAESF8(pkt);
         }
 
         /* Authenticate the packet */
-        if (policy.getAuthType() == SRTPPolicy.HMACSHA1_AUTHENTICATION) {
+        if (policy.getAuthType() == SRTPPolicy.HMACSHA1_AUTHENTICATION)
+        {
             authenticatePacketHMCSHA1(pkt, roc);
             pkt.append(tagStore, policy.getAuthTagLength());
         }
 
         /* Update the ROC if necessary */
         int seqNo = pkt.getSequenceNumber();
-        if (seqNo == 0xFFFF) {
+        if (seqNo == 0xFFFF)
+        {
             roc++;
         }
     }
@@ -509,7 +513,7 @@ public void processPacketAESF8(RawPacket pkt) {
      */
     private void authenticatePacketHMCSHA1(RawPacket pkt, int rocIn) 
     {
-        hmacSha1.update(pkt.getBuffer(), 0, pkt.getLength());
+        hmacSha1.update(pkt.getBuffer(), pkt.getOffset(), pkt.getLength());
         // byte[] rb = new byte[4];
         rbStore[0] = (byte) (rocIn >> 24);
         rbStore[1] = (byte) (rocIn >> 16);