[ONOS-2939] Let sdn-ip also can parse bird's bgp OPEN message

RFC5492 allows multiple Capability triples per Optional Parameter.
But our code only support parsing 1 Capability triple per Optional Parameter.
It works with Quagga, but failed parsing bird OPEN message.
This patch adds support for multiple Capability triples per Optional Parameter.

Change-Id: Iae6295d608e44676a44ef6a0ae1868d8dcd7648d

@@ -309,16 +309,25 @@ final class BgpOpen {
             case BgpConstants.Open.Capabilities.TYPE:
             case BgpConstants.Open.Capabilities.TYPE:
                 // Optional Parameter Type: Capabilities
                 // Optional Parameter Type: Capabilities
                 if (paramLen < BgpConstants.Open.Capabilities.MIN_LENGTH) {
                 if (paramLen < BgpConstants.Open.Capabilities.MIN_LENGTH) {
-                    // ERROR: Malformed Capability
-                    String errorMsg = "Malformed Capability Type " + paramType;
+                    // ERROR: Malformed Param Type
+                    String errorMsg = "Malformed Capabilities Optional "
+                            + "Parameter Type " + paramType;
+                    throw new BgpMessage.BgpParseException(errorMsg);
+                }
+                int paramEnd = message.readerIndex() + paramLen;
+                // Parse Capabilities
+                while (message.readerIndex() < paramEnd) {
+                    if (paramEnd - message.readerIndex() <
+                            BgpConstants.Open.Capabilities.MIN_LENGTH) {
+                        String errorMsg = "Malformed Capabilities";
                         throw new BgpMessage.BgpParseException(errorMsg);
                         throw new BgpMessage.BgpParseException(errorMsg);
                     }
                     }
-                int capabEnd = message.readerIndex() + paramLen;
                     int capabCode = message.readUnsignedByte();
                     int capabCode = message.readUnsignedByte();
                     int capabLen = message.readUnsignedByte();
                     int capabLen = message.readUnsignedByte();
-                if (message.readerIndex() + capabLen > capabEnd) {
+                    if (message.readerIndex() + capabLen > paramEnd) {
                         // ERROR: Malformed Capability
                         // ERROR: Malformed Capability
-                    String errorMsg = "Malformed Capability Type " + paramType;
+                        String errorMsg = "Malformed Capability instance with "
+                                + "code " + capabCode;
                         throw new BgpMessage.BgpParseException(errorMsg);
                         throw new BgpMessage.BgpParseException(errorMsg);
                     }
                     }
 
 
@@ -395,8 +404,9 @@ final class BgpOpen {
                         break;
                         break;
                     }
                     }
 
 
-                break;
 
 
+                }
+                break;
             default:
             default:
                 // Unknown Parameter Type: ignore it
                 // Unknown Parameter Type: ignore it
                 log.debug("BGP RX OPEN Parameter Type = {} Length = {}",
                 log.debug("BGP RX OPEN Parameter Type = {} Length = {}",