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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.ChannelHandlerContext;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* A class for handling BGP NOTIFICATION messages.
*/
final class BgpNotification {
private static final Logger log =
LoggerFactory.getLogger(BgpNotification.class);
/**
* Default constructor.
* <p>
* The constructor is private to prevent creating an instance of
* this utility class.
*/
private BgpNotification() {
}
/**
* Processes BGP NOTIFICATION message.
*
* @param bgpSession the BGP Session to use
* @param ctx the Channel Handler Context
* @param message the message to process
*/
static void processBgpNotification(BgpSession bgpSession,
ChannelHandlerContext ctx,
ChannelBuffer message) {
int minLength =
BgpConstants.BGP_NOTIFICATION_MIN_LENGTH - BgpConstants.BGP_HEADER_LENGTH;
if (message.readableBytes() < minLength) {
log.debug("BGP RX NOTIFICATION Error from {}: " +
"Message length {} too short. Must be at least {}",
bgpSession.remoteInfo().address(),
message.readableBytes(), minLength);
//
// ERROR: Bad Message Length
//
// NOTE: We do NOT send NOTIFICATION in response to a notification
return;
}
//
// Parse the NOTIFICATION message
//
int errorCode = message.readUnsignedByte();
int errorSubcode = message.readUnsignedByte();
int dataLength = message.readableBytes();
log.debug("BGP RX NOTIFICATION message from {}: Error Code {} " +
"Error Subcode {} Data Length {}",
bgpSession.remoteInfo().address(), errorCode, errorSubcode,
dataLength);
//
// NOTE: If the peer sent a NOTIFICATION, we leave it to the peer to
// close the connection.
//
// Start the Session Timeout timer
bgpSession.restartSessionTimeoutTimer(ctx);
}
/**
* Prepares BGP NOTIFICATION message.
*
* @param errorCode the BGP NOTIFICATION Error Code
* @param errorSubcode the BGP NOTIFICATION Error Subcode if applicable,
* otherwise BgpConstants.Notifications.ERROR_SUBCODE_UNSPECIFIC
* @param data the BGP NOTIFICATION Data if applicable, otherwise null
* @return the message to transmit (BGP header included)
*/
static ChannelBuffer prepareBgpNotification(int errorCode,
int errorSubcode,
ChannelBuffer data) {
ChannelBuffer message =
ChannelBuffers.buffer(BgpConstants.BGP_MESSAGE_MAX_LENGTH);
//
// Prepare the NOTIFICATION message payload
//
message.writeByte(errorCode);
message.writeByte(errorSubcode);
if (data != null) {
message.writeBytes(data);
}
return BgpMessage.prepareBgpMessage(BgpConstants.BGP_TYPE_NOTIFICATION,
message);
}
/**
* Prepares BGP NOTIFICATION message: Bad Message Length.
*
* @param length the erroneous Length field
* @return the message to transmit (BGP header included)
*/
static ChannelBuffer prepareBgpNotificationBadMessageLength(int length) {
int errorCode = BgpConstants.Notifications.MessageHeaderError.ERROR_CODE;
int errorSubcode = BgpConstants.Notifications.MessageHeaderError.BAD_MESSAGE_LENGTH;
ChannelBuffer data = ChannelBuffers.buffer(2);
data.writeShort(length);
return prepareBgpNotification(errorCode, errorSubcode, data);
}
}
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