| /* |
| * Copyright 2017-present 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.jboss.netty.channel.ChannelStateEvent; |
| import org.jboss.netty.channel.SimpleChannelHandler; |
| import org.onlab.packet.Ip4Address; |
| import org.onlab.packet.Ip4Prefix; |
| |
| import java.util.Collection; |
| |
| /** |
| * Class for handling the remote BGP Peer session. |
| */ |
| class TestBgpPeerChannelHandler extends SimpleChannelHandler { |
| static final long PEER_AS = 65001; |
| static final long PEER_AS4 = 0x12345678; |
| static final int PEER_HOLDTIME = 120; // 120 seconds |
| |
| final BgpSessionInfo localInfo = new BgpSessionInfo(); |
| ChannelHandlerContext savedCtx; |
| |
| /** |
| * Constructor for given BGP ID. |
| * |
| * @param bgpId the BGP ID to use |
| */ |
| TestBgpPeerChannelHandler(Ip4Address bgpId) { |
| this.localInfo.setBgpVersion(BgpConstants.BGP_VERSION); |
| this.localInfo.setBgpId(bgpId); |
| this.localInfo.setAsNumber(PEER_AS); |
| this.localInfo.setHoldtime(PEER_HOLDTIME); |
| } |
| |
| /** |
| * Closes the channel. |
| */ |
| void closeChannel() { |
| savedCtx.getChannel().close(); |
| } |
| |
| @Override |
| public void channelConnected(ChannelHandlerContext ctx, |
| ChannelStateEvent channelEvent) { |
| this.savedCtx = ctx; |
| // Prepare and transmit BGP OPEN message |
| ChannelBuffer message = BgpOpen.prepareBgpOpen(localInfo); |
| ctx.getChannel().write(message); |
| |
| // Prepare and transmit BGP KEEPALIVE message |
| message = BgpKeepalive.prepareBgpKeepalive(); |
| ctx.getChannel().write(message); |
| } |
| |
| @Override |
| public void channelDisconnected(ChannelHandlerContext ctx, |
| ChannelStateEvent channelEvent) { |
| // Nothing to do |
| } |
| |
| /** |
| * Prepares BGP UPDATE message. |
| * |
| * @param nextHopRouter the next-hop router address for the routes to add |
| * @param localPref the local preference for the routes to use |
| * @param multiExitDisc the MED value |
| * @param asPath the AS path for the routes to add |
| * @param addedRoutes the routes to add |
| * @param withdrawnRoutes the routes to withdraw |
| * @return the message to transmit (BGP header included) |
| */ |
| ChannelBuffer prepareBgpUpdate(Ip4Address nextHopRouter, |
| long localPref, |
| long multiExitDisc, |
| BgpRouteEntry.AsPath asPath, |
| Collection<Ip4Prefix> addedRoutes, |
| Collection<Ip4Prefix> withdrawnRoutes) { |
| int attrFlags; |
| ChannelBuffer message = |
| ChannelBuffers.buffer(BgpConstants.BGP_MESSAGE_MAX_LENGTH); |
| ChannelBuffer pathAttributes = |
| ChannelBuffers.buffer(BgpConstants.BGP_MESSAGE_MAX_LENGTH); |
| |
| // Encode the Withdrawn Routes |
| ChannelBuffer encodedPrefixes = encodePackedPrefixes(withdrawnRoutes); |
| message.writeShort(encodedPrefixes.readableBytes()); |
| message.writeBytes(encodedPrefixes); |
| |
| // Encode the Path Attributes |
| // ORIGIN: IGP |
| attrFlags = 0x40; // Transitive flag |
| pathAttributes.writeByte(attrFlags); |
| pathAttributes.writeByte(BgpConstants.Update.Origin.TYPE); |
| pathAttributes.writeByte(1); // Data length |
| pathAttributes.writeByte(BgpConstants.Update.Origin.IGP); |
| |
| // AS_PATH: asPath |
| attrFlags = 0x40; // Transitive flag |
| pathAttributes.writeByte(attrFlags); |
| pathAttributes.writeByte(BgpConstants.Update.AsPath.TYPE); |
| ChannelBuffer encodedAsPath = encodeAsPath(asPath); |
| pathAttributes.writeByte(encodedAsPath.readableBytes()); // Data length |
| pathAttributes.writeBytes(encodedAsPath); |
| // NEXT_HOP: nextHopRouter |
| attrFlags = 0x40; // Transitive flag |
| pathAttributes.writeByte(attrFlags); |
| pathAttributes.writeByte(BgpConstants.Update.NextHop.TYPE); |
| pathAttributes.writeByte(4); // Data length |
| pathAttributes.writeInt(nextHopRouter.toInt()); // Next-hop router |
| // LOCAL_PREF: localPref |
| attrFlags = 0x40; // Transitive flag |
| pathAttributes.writeByte(attrFlags); |
| pathAttributes.writeByte(BgpConstants.Update.LocalPref.TYPE); |
| pathAttributes.writeByte(4); // Data length |
| pathAttributes.writeInt((int) localPref); // Preference value |
| // MULTI_EXIT_DISC: multiExitDisc |
| attrFlags = 0x80; // Optional |
| // Non-Transitive flag |
| pathAttributes.writeByte(attrFlags); |
| pathAttributes.writeByte(BgpConstants.Update.MultiExitDisc.TYPE); |
| pathAttributes.writeByte(4); // Data length |
| pathAttributes.writeInt((int) multiExitDisc); // Preference value |
| // The NLRI prefixes |
| encodedPrefixes = encodePackedPrefixes(addedRoutes); |
| |
| // Write the Path Attributes, beginning with its length |
| message.writeShort(pathAttributes.readableBytes()); |
| message.writeBytes(pathAttributes); |
| message.writeBytes(encodedPrefixes); |
| |
| return BgpMessage.prepareBgpMessage(BgpConstants.BGP_TYPE_UPDATE, |
| message); |
| } |
| |
| /** |
| * Encodes a collection of IPv4 network prefixes in a packed format. |
| * <p> |
| * The IPv4 prefixes are encoded in the form: |
| * <Length, Prefix> where Length is the length in bits of the IPv4 prefix, |
| * and Prefix is the IPv4 prefix (padded with trailing bits to the end |
| * of an octet). |
| * |
| * @param prefixes the prefixes to encode |
| * @return the buffer with the encoded prefixes |
| */ |
| private ChannelBuffer encodePackedPrefixes(Collection<Ip4Prefix> prefixes) { |
| ChannelBuffer message = |
| ChannelBuffers.buffer(BgpConstants.BGP_MESSAGE_MAX_LENGTH); |
| |
| // Write each of the prefixes |
| for (Ip4Prefix prefix : prefixes) { |
| int prefixBitlen = prefix.prefixLength(); |
| int prefixBytelen = (prefixBitlen + 7) / 8; // Round-up |
| message.writeByte(prefixBitlen); |
| |
| Ip4Address address = prefix.address(); |
| long value = address.toInt() & 0xffffffffL; |
| for (int i = 0; i < Ip4Address.BYTE_LENGTH; i++) { |
| if (prefixBytelen-- == 0) { |
| break; |
| } |
| long nextByte = |
| (value >> ((Ip4Address.BYTE_LENGTH - i - 1) * 8)) & 0xff; |
| message.writeByte((int) nextByte); |
| } |
| } |
| |
| return message; |
| } |
| |
| /** |
| * Encodes an AS path. |
| * |
| * @param asPath the AS path to encode |
| * @return the buffer with the encoded AS path |
| */ |
| private ChannelBuffer encodeAsPath(BgpRouteEntry.AsPath asPath) { |
| ChannelBuffer message = |
| ChannelBuffers.buffer(BgpConstants.BGP_MESSAGE_MAX_LENGTH); |
| |
| for (BgpRouteEntry.PathSegment pathSegment : asPath.getPathSegments()) { |
| message.writeByte(pathSegment.getType()); |
| message.writeByte(pathSegment.getSegmentAsNumbers().size()); |
| for (Long asNumber : pathSegment.getSegmentAsNumbers()) { |
| message.writeShort(asNumber.intValue()); |
| } |
| } |
| |
| return message; |
| } |
| } |