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/*
* Copyright 2014-2015 Open Networking Laboratory
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.onosproject.routing.bgp;
import org.jboss.netty.buffer.ChannelBuffer;
import org.jboss.netty.buffer.ChannelBuffers;
import org.jboss.netty.channel.Channel;
import org.jboss.netty.channel.ChannelHandlerContext;
import org.jboss.netty.handler.codec.frame.FrameDecoder;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* Class for handling the decoding of the BGP messages.
*/
class BgpFrameDecoder extends FrameDecoder {
private static final Logger log =
LoggerFactory.getLogger(BgpFrameDecoder.class);
private final BgpSession bgpSession;
/**
* Constructor for a given BGP Session.
*
* @param bgpSession the BGP session state to use.
*/
BgpFrameDecoder(BgpSession bgpSession) {
this.bgpSession = bgpSession;
}
@Override
protected Object decode(ChannelHandlerContext ctx,
Channel channel,
ChannelBuffer buf) throws Exception {
//
// NOTE: If we close the channel during the decoding, we might still
// see some incoming messages while the channel closing is completed.
//
if (bgpSession.isClosed()) {
return null;
}
log.trace("BGP Peer: decode(): remoteAddr = {} localAddr = {} " +
"messageSize = {}",
ctx.getChannel().getRemoteAddress(),
ctx.getChannel().getLocalAddress(),
buf.readableBytes());
// Test for minimum length of the BGP message
if (buf.readableBytes() < BgpConstants.BGP_HEADER_LENGTH) {
// No enough data received
return null;
}
//
// Mark the current buffer position in case we haven't received
// the whole message.
//
buf.markReaderIndex();
//
// Read and check the BGP message Marker field: it must be all ones
// (See RFC 4271, Section 4.1)
//
byte[] marker = new byte[BgpConstants.BGP_HEADER_MARKER_LENGTH];
buf.readBytes(marker);
for (int i = 0; i < marker.length; i++) {
if (marker[i] != (byte) 0xff) {
log.debug("BGP RX Error: invalid marker {} at position {}",
marker[i], i);
//
// ERROR: Connection Not Synchronized
//
// Send NOTIFICATION and close the connection
int errorCode = BgpConstants.Notifications.MessageHeaderError.ERROR_CODE;
int errorSubcode =
BgpConstants.Notifications.MessageHeaderError.CONNECTION_NOT_SYNCHRONIZED;
ChannelBuffer txMessage =
BgpNotification.prepareBgpNotification(errorCode,
errorSubcode,
null);
ctx.getChannel().write(txMessage);
bgpSession.closeSession(ctx);
return null;
}
}
//
// Read and check the BGP message Length field
//
int length = buf.readUnsignedShort();
if ((length < BgpConstants.BGP_HEADER_LENGTH) ||
(length > BgpConstants.BGP_MESSAGE_MAX_LENGTH)) {
log.debug("BGP RX Error: invalid Length field {}. " +
"Must be between {} and {}",
length,
BgpConstants.BGP_HEADER_LENGTH,
BgpConstants.BGP_MESSAGE_MAX_LENGTH);
//
// ERROR: Bad Message Length
//
// Send NOTIFICATION and close the connection
ChannelBuffer txMessage =
BgpNotification.prepareBgpNotificationBadMessageLength(length);
ctx.getChannel().write(txMessage);
bgpSession.closeSession(ctx);
return null;
}
//
// Test whether the rest of the message is received:
// So far we have read the Marker (16 octets) and the
// Length (2 octets) fields.
//
int remainingMessageLen =
length - BgpConstants.BGP_HEADER_MARKER_LENGTH - 2;
if (buf.readableBytes() < remainingMessageLen) {
// No enough data received
buf.resetReaderIndex();
return null;
}
//
// Read the BGP message Type field, and process based on that type
//
int type = buf.readUnsignedByte();
remainingMessageLen--; // Adjust after reading the type
ChannelBuffer message = buf.readBytes(remainingMessageLen);
//
// Process the remaining of the message based on the message type
//
switch (type) {
case BgpConstants.BGP_TYPE_OPEN:
BgpOpen.processBgpOpen(bgpSession, ctx, message);
break;
case BgpConstants.BGP_TYPE_UPDATE:
BgpUpdate.processBgpUpdate(bgpSession, ctx, message);
break;
case BgpConstants.BGP_TYPE_NOTIFICATION:
BgpNotification.processBgpNotification(bgpSession, ctx, message);
break;
case BgpConstants.BGP_TYPE_KEEPALIVE:
BgpKeepalive.processBgpKeepalive(bgpSession, ctx, message);
break;
default:
//
// ERROR: Bad Message Type
//
// Send NOTIFICATION and close the connection
int errorCode = BgpConstants.Notifications.MessageHeaderError.ERROR_CODE;
int errorSubcode = BgpConstants.Notifications.MessageHeaderError.BAD_MESSAGE_TYPE;
ChannelBuffer data = ChannelBuffers.buffer(1);
data.writeByte(type);
ChannelBuffer txMessage =
BgpNotification.prepareBgpNotification(errorCode, errorSubcode,
data);
ctx.getChannel().write(txMessage);
bgpSession.closeSession(ctx);
return null;
}
return null;
}
}
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