Jonathan Hart | 20d8e51 | 2014-10-16 11:05:52 -0700 | [diff] [blame] | 1 | package org.onlab.onos.sdnip.bgp; |
| 2 | |
| 3 | import java.util.Collection; |
| 4 | |
| 5 | import org.jboss.netty.buffer.ChannelBuffer; |
| 6 | import org.jboss.netty.buffer.ChannelBuffers; |
| 7 | import org.jboss.netty.channel.ChannelHandlerContext; |
| 8 | import org.jboss.netty.channel.ChannelStateEvent; |
| 9 | import org.jboss.netty.channel.SimpleChannelHandler; |
| 10 | import org.onlab.packet.IpAddress; |
| 11 | import org.onlab.packet.IpPrefix; |
| 12 | |
| 13 | /** |
| 14 | * Class for handling the remote BGP Peer session. |
| 15 | */ |
| 16 | class TestBgpPeerChannelHandler extends SimpleChannelHandler { |
| 17 | static final long PEER_AS = 65001; |
| 18 | static final int PEER_HOLDTIME = 120; // 120 seconds |
| 19 | final IpAddress bgpId; // The BGP ID |
| 20 | final long localPref; // Local preference for routes |
| 21 | final long multiExitDisc = 20; // MED value |
| 22 | |
| 23 | ChannelHandlerContext savedCtx; |
| 24 | |
| 25 | /** |
| 26 | * Constructor for given BGP ID. |
| 27 | * |
| 28 | * @param bgpId the BGP ID to use |
| 29 | * @param localPref the local preference for the routes to use |
| 30 | */ |
| 31 | TestBgpPeerChannelHandler(IpAddress bgpId, |
| 32 | long localPref) { |
| 33 | this.bgpId = bgpId; |
| 34 | this.localPref = localPref; |
| 35 | } |
| 36 | |
| 37 | /** |
| 38 | * Closes the channel. |
| 39 | */ |
| 40 | void closeChannel() { |
| 41 | savedCtx.getChannel().close(); |
| 42 | } |
| 43 | |
| 44 | @Override |
| 45 | public void channelConnected(ChannelHandlerContext ctx, |
| 46 | ChannelStateEvent channelEvent) { |
| 47 | this.savedCtx = ctx; |
| 48 | // Prepare and transmit BGP OPEN message |
| 49 | ChannelBuffer message = prepareBgpOpen(); |
| 50 | ctx.getChannel().write(message); |
| 51 | |
| 52 | // Prepare and transmit BGP KEEPALIVE message |
| 53 | message = prepareBgpKeepalive(); |
| 54 | ctx.getChannel().write(message); |
| 55 | } |
| 56 | |
| 57 | @Override |
| 58 | public void channelDisconnected(ChannelHandlerContext ctx, |
| 59 | ChannelStateEvent channelEvent) { |
| 60 | // Nothing to do |
| 61 | } |
| 62 | |
| 63 | /** |
| 64 | * Prepares BGP OPEN message. |
| 65 | * |
| 66 | * @return the message to transmit (BGP header included) |
| 67 | */ |
| 68 | ChannelBuffer prepareBgpOpen() { |
| 69 | ChannelBuffer message = |
| 70 | ChannelBuffers.buffer(BgpConstants.BGP_MESSAGE_MAX_LENGTH); |
| 71 | message.writeByte(BgpConstants.BGP_VERSION); |
| 72 | message.writeShort((int) PEER_AS); |
| 73 | message.writeShort(PEER_HOLDTIME); |
| 74 | message.writeInt(bgpId.toInt()); |
| 75 | message.writeByte(0); // No Optional Parameters |
| 76 | return prepareBgpMessage(BgpConstants.BGP_TYPE_OPEN, message); |
| 77 | } |
| 78 | |
| 79 | /** |
| 80 | * Prepares BGP UPDATE message. |
| 81 | * |
| 82 | * @param nextHopRouter the next-hop router address for the routes to add |
| 83 | * @param addedRoutes the routes to add |
| 84 | * @param withdrawnRoutes the routes to withdraw |
| 85 | * @return the message to transmit (BGP header included) |
| 86 | */ |
| 87 | ChannelBuffer prepareBgpUpdate(IpAddress nextHopRouter, |
| 88 | Collection<IpPrefix> addedRoutes, |
| 89 | Collection<IpPrefix> withdrawnRoutes) { |
| 90 | int attrFlags; |
| 91 | ChannelBuffer message = |
| 92 | ChannelBuffers.buffer(BgpConstants.BGP_MESSAGE_MAX_LENGTH); |
| 93 | ChannelBuffer pathAttributes = |
| 94 | ChannelBuffers.buffer(BgpConstants.BGP_MESSAGE_MAX_LENGTH); |
| 95 | |
| 96 | // Encode the Withdrawn Routes |
| 97 | ChannelBuffer encodedPrefixes = encodePackedPrefixes(withdrawnRoutes); |
| 98 | message.writeShort(encodedPrefixes.readableBytes()); |
| 99 | message.writeBytes(encodedPrefixes); |
| 100 | |
| 101 | // Encode the Path Attributes |
| 102 | // ORIGIN: IGP |
| 103 | attrFlags = 0x40; // Transitive flag |
| 104 | pathAttributes.writeByte(attrFlags); |
| 105 | pathAttributes.writeByte(BgpConstants.Update.Origin.TYPE); |
| 106 | pathAttributes.writeByte(1); // Data length |
| 107 | pathAttributes.writeByte(BgpConstants.Update.Origin.IGP); |
| 108 | // AS_PATH: Two Path Segments of 3 ASes each |
| 109 | attrFlags = 0x40; // Transitive flag |
| 110 | pathAttributes.writeByte(attrFlags); |
| 111 | pathAttributes.writeByte(BgpConstants.Update.AsPath.TYPE); |
| 112 | pathAttributes.writeByte(16); // Data length |
| 113 | byte pathSegmentType1 = (byte) BgpConstants.Update.AsPath.AS_SEQUENCE; |
| 114 | pathAttributes.writeByte(pathSegmentType1); |
| 115 | pathAttributes.writeByte(3); // Three ASes |
| 116 | pathAttributes.writeShort(65010); // AS=65010 |
| 117 | pathAttributes.writeShort(65020); // AS=65020 |
| 118 | pathAttributes.writeShort(65030); // AS=65030 |
| 119 | byte pathSegmentType2 = (byte) BgpConstants.Update.AsPath.AS_SET; |
| 120 | pathAttributes.writeByte(pathSegmentType2); |
| 121 | pathAttributes.writeByte(3); // Three ASes |
| 122 | pathAttributes.writeShort(65041); // AS=65041 |
| 123 | pathAttributes.writeShort(65042); // AS=65042 |
| 124 | pathAttributes.writeShort(65043); // AS=65043 |
| 125 | // NEXT_HOP: nextHopRouter |
| 126 | attrFlags = 0x40; // Transitive flag |
| 127 | pathAttributes.writeByte(attrFlags); |
| 128 | pathAttributes.writeByte(BgpConstants.Update.NextHop.TYPE); |
| 129 | pathAttributes.writeByte(4); // Data length |
| 130 | pathAttributes.writeInt(nextHopRouter.toInt()); // Next-hop router |
| 131 | // LOCAL_PREF: localPref |
| 132 | attrFlags = 0x40; // Transitive flag |
| 133 | pathAttributes.writeByte(attrFlags); |
| 134 | pathAttributes.writeByte(BgpConstants.Update.LocalPref.TYPE); |
| 135 | pathAttributes.writeByte(4); // Data length |
| 136 | pathAttributes.writeInt((int) localPref); // Preference value |
| 137 | // MULTI_EXIT_DISC: multiExitDisc |
| 138 | attrFlags = 0x80; // Optional |
| 139 | // Non-Transitive flag |
| 140 | pathAttributes.writeByte(attrFlags); |
| 141 | pathAttributes.writeByte(BgpConstants.Update.MultiExitDisc.TYPE); |
| 142 | pathAttributes.writeByte(4); // Data length |
| 143 | pathAttributes.writeInt((int) multiExitDisc); // Preference value |
| 144 | // The NLRI prefixes |
| 145 | encodedPrefixes = encodePackedPrefixes(addedRoutes); |
| 146 | |
| 147 | // Write the Path Attributes, beginning with its length |
| 148 | message.writeShort(pathAttributes.readableBytes()); |
| 149 | message.writeBytes(pathAttributes); |
| 150 | message.writeBytes(encodedPrefixes); |
| 151 | |
| 152 | return prepareBgpMessage(BgpConstants.BGP_TYPE_UPDATE, message); |
| 153 | } |
| 154 | |
| 155 | /** |
| 156 | * Encodes a collection of IPv4 network prefixes in a packed format. |
| 157 | * <p> |
| 158 | * The IPv4 prefixes are encoded in the form: |
| 159 | * <Length, Prefix> where Length is the length in bits of the IPv4 prefix, |
| 160 | * and Prefix is the IPv4 prefix (padded with trailing bits to the end |
| 161 | * of an octet). |
| 162 | * |
| 163 | * @param prefixes the prefixes to encode |
| 164 | * @return the buffer with the encoded prefixes |
| 165 | */ |
| 166 | private ChannelBuffer encodePackedPrefixes(Collection<IpPrefix> prefixes) { |
| 167 | ChannelBuffer message = |
| 168 | ChannelBuffers.buffer(BgpConstants.BGP_MESSAGE_MAX_LENGTH); |
| 169 | |
| 170 | // Write each of the prefixes |
| 171 | for (IpPrefix prefix : prefixes) { |
| 172 | int prefixBitlen = prefix.prefixLength(); |
| 173 | int prefixBytelen = (prefixBitlen + 7) / 8; // Round-up |
| 174 | message.writeByte(prefixBitlen); |
| 175 | |
| 176 | IpAddress address = prefix.toIpAddress(); |
| 177 | long value = address.toInt() & 0xffffffffL; |
| 178 | for (int i = 0; i < IpAddress.INET_LEN; i++) { |
| 179 | if (prefixBytelen-- == 0) { |
| 180 | break; |
| 181 | } |
| 182 | long nextByte = |
| 183 | (value >> ((IpAddress.INET_LEN - i - 1) * 8)) & 0xff; |
| 184 | message.writeByte((int) nextByte); |
| 185 | } |
| 186 | } |
| 187 | |
| 188 | return message; |
| 189 | } |
| 190 | |
| 191 | /** |
| 192 | * Prepares BGP KEEPALIVE message. |
| 193 | * |
| 194 | * @return the message to transmit (BGP header included) |
| 195 | */ |
| 196 | ChannelBuffer prepareBgpKeepalive() { |
| 197 | ChannelBuffer message = |
| 198 | ChannelBuffers.buffer(BgpConstants.BGP_MESSAGE_MAX_LENGTH); |
| 199 | return prepareBgpMessage(BgpConstants.BGP_TYPE_KEEPALIVE, message); |
| 200 | } |
| 201 | |
| 202 | /** |
| 203 | * Prepares BGP NOTIFICATION message. |
| 204 | * |
| 205 | * @param errorCode the BGP NOTIFICATION Error Code |
| 206 | * @param errorSubcode the BGP NOTIFICATION Error Subcode if applicable, |
| 207 | * otherwise BgpConstants.Notifications.ERROR_SUBCODE_UNSPECIFIC |
| 208 | * @param payload the BGP NOTIFICATION Data if applicable, otherwise null |
| 209 | * @return the message to transmit (BGP header included) |
| 210 | */ |
| 211 | ChannelBuffer prepareBgpNotification(int errorCode, int errorSubcode, |
| 212 | ChannelBuffer data) { |
| 213 | ChannelBuffer message = |
| 214 | ChannelBuffers.buffer(BgpConstants.BGP_MESSAGE_MAX_LENGTH); |
| 215 | // Prepare the NOTIFICATION message payload |
| 216 | message.writeByte(errorCode); |
| 217 | message.writeByte(errorSubcode); |
| 218 | if (data != null) { |
| 219 | message.writeBytes(data); |
| 220 | } |
| 221 | return prepareBgpMessage(BgpConstants.BGP_TYPE_NOTIFICATION, message); |
| 222 | } |
| 223 | |
| 224 | /** |
| 225 | * Prepares BGP message. |
| 226 | * |
| 227 | * @param type the BGP message type |
| 228 | * @param payload the message payload to transmit (BGP header excluded) |
| 229 | * @return the message to transmit (BGP header included) |
| 230 | */ |
| 231 | private ChannelBuffer prepareBgpMessage(int type, ChannelBuffer payload) { |
| 232 | ChannelBuffer message = |
| 233 | ChannelBuffers.buffer(BgpConstants.BGP_HEADER_LENGTH + |
| 234 | payload.readableBytes()); |
| 235 | |
| 236 | // Write the marker |
| 237 | for (int i = 0; i < BgpConstants.BGP_HEADER_MARKER_LENGTH; i++) { |
| 238 | message.writeByte(0xff); |
| 239 | } |
| 240 | |
| 241 | // Write the rest of the BGP header |
| 242 | message.writeShort(BgpConstants.BGP_HEADER_LENGTH + |
| 243 | payload.readableBytes()); |
| 244 | message.writeByte(type); |
| 245 | |
| 246 | // Write the payload |
| 247 | message.writeBytes(payload); |
| 248 | return message; |
| 249 | } |
| 250 | } |