Pavlin Radoslavov | 80f3e18 | 2014-12-15 10:46:18 -0800 | [diff] [blame] | 1 | /* |
| 2 | * Copyright 2014 Open Networking Laboratory |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | package org.onosproject.sdnip.bgp; |
| 17 | |
| 18 | import org.jboss.netty.buffer.ChannelBuffer; |
| 19 | import org.jboss.netty.buffer.ChannelBuffers; |
| 20 | import org.jboss.netty.channel.ChannelHandlerContext; |
| 21 | import org.onlab.packet.Ip4Address; |
| 22 | import org.onosproject.sdnip.bgp.BgpConstants.Notifications; |
| 23 | import org.onosproject.sdnip.bgp.BgpConstants.Notifications.OpenMessageError; |
Pavlin Radoslavov | 278cdde | 2014-12-16 14:09:31 -0800 | [diff] [blame] | 24 | import org.onosproject.sdnip.bgp.BgpConstants.Open.Capabilities; |
| 25 | import org.onosproject.sdnip.bgp.BgpConstants.Open.Capabilities.MultiprotocolExtensions; |
| 26 | import org.onosproject.sdnip.bgp.BgpMessage.BgpParseException; |
Pavlin Radoslavov | 80f3e18 | 2014-12-15 10:46:18 -0800 | [diff] [blame] | 27 | import org.slf4j.Logger; |
| 28 | import org.slf4j.LoggerFactory; |
| 29 | |
| 30 | /** |
| 31 | * A class for handling BGP OPEN messages. |
| 32 | */ |
| 33 | final class BgpOpen { |
| 34 | private static final Logger log = LoggerFactory.getLogger(BgpOpen.class); |
| 35 | |
| 36 | /** |
| 37 | * Default constructor. |
| 38 | * <p> |
| 39 | * The constructor is private to prevent creating an instance of |
| 40 | * this utility class. |
| 41 | */ |
| 42 | private BgpOpen() { |
| 43 | } |
| 44 | |
| 45 | /** |
| 46 | * Processes BGP OPEN message. |
| 47 | * |
| 48 | * @param bgpSession the BGP Session to use |
| 49 | * @param ctx the Channel Handler Context |
| 50 | * @param message the message to process |
| 51 | */ |
| 52 | static void processBgpOpen(BgpSession bgpSession, |
| 53 | ChannelHandlerContext ctx, |
| 54 | ChannelBuffer message) { |
| 55 | int minLength = |
| 56 | BgpConstants.BGP_OPEN_MIN_LENGTH - BgpConstants.BGP_HEADER_LENGTH; |
| 57 | if (message.readableBytes() < minLength) { |
| 58 | log.debug("BGP RX OPEN Error from {}: " + |
| 59 | "Message length {} too short. Must be at least {}", |
| 60 | bgpSession.getRemoteAddress(), message.readableBytes(), |
| 61 | minLength); |
| 62 | // |
| 63 | // ERROR: Bad Message Length |
| 64 | // |
| 65 | // Send NOTIFICATION and close the connection |
| 66 | ChannelBuffer txMessage = |
| 67 | BgpNotification.prepareBgpNotificationBadMessageLength( |
| 68 | message.readableBytes() + BgpConstants.BGP_HEADER_LENGTH); |
| 69 | ctx.getChannel().write(txMessage); |
| 70 | bgpSession.closeSession(ctx); |
| 71 | return; |
| 72 | } |
| 73 | |
| 74 | // |
| 75 | // Parse the OPEN message |
| 76 | // |
| 77 | // Remote BGP version |
| 78 | int remoteBgpVersion = message.readUnsignedByte(); |
| 79 | if (remoteBgpVersion != BgpConstants.BGP_VERSION) { |
| 80 | log.debug("BGP RX OPEN Error from {}: " + |
| 81 | "Unsupported BGP version {}. Should be {}", |
| 82 | bgpSession.getRemoteAddress(), remoteBgpVersion, |
| 83 | BgpConstants.BGP_VERSION); |
| 84 | // |
| 85 | // ERROR: Unsupported Version Number |
| 86 | // |
| 87 | // Send NOTIFICATION and close the connection |
| 88 | int errorCode = OpenMessageError.ERROR_CODE; |
| 89 | int errorSubcode = OpenMessageError.UNSUPPORTED_VERSION_NUMBER; |
| 90 | ChannelBuffer data = ChannelBuffers.buffer(2); |
| 91 | data.writeShort(BgpConstants.BGP_VERSION); |
| 92 | ChannelBuffer txMessage = |
| 93 | BgpNotification.prepareBgpNotification(errorCode, errorSubcode, |
| 94 | data); |
| 95 | ctx.getChannel().write(txMessage); |
| 96 | bgpSession.closeSession(ctx); |
| 97 | return; |
| 98 | } |
| 99 | bgpSession.setRemoteBgpVersion(remoteBgpVersion); |
| 100 | |
| 101 | // Remote AS number |
| 102 | long remoteAs = message.readUnsignedShort(); |
| 103 | // |
| 104 | // Verify that the AS number is same for all other BGP Sessions |
| 105 | // NOTE: This check applies only for our use-case where all BGP |
| 106 | // sessions are iBGP. |
| 107 | // |
| 108 | for (BgpSession bs : bgpSession.getBgpSessionManager().getBgpSessions()) { |
| 109 | if ((bs.getRemoteAs() != 0) && (remoteAs != bs.getRemoteAs())) { |
| 110 | log.debug("BGP RX OPEN Error from {}: Bad Peer AS {}. " + |
| 111 | "Expected {}", |
| 112 | bgpSession.getRemoteAddress(), remoteAs, |
| 113 | bs.getRemoteAs()); |
| 114 | // |
| 115 | // ERROR: Bad Peer AS |
| 116 | // |
| 117 | // Send NOTIFICATION and close the connection |
| 118 | int errorCode = OpenMessageError.ERROR_CODE; |
| 119 | int errorSubcode = OpenMessageError.BAD_PEER_AS; |
| 120 | ChannelBuffer txMessage = |
| 121 | BgpNotification.prepareBgpNotification(errorCode, |
| 122 | errorSubcode, null); |
| 123 | ctx.getChannel().write(txMessage); |
| 124 | bgpSession.closeSession(ctx); |
| 125 | return; |
| 126 | } |
| 127 | } |
| 128 | bgpSession.setRemoteAs(remoteAs); |
| 129 | |
| 130 | // Remote Hold Time |
| 131 | long remoteHoldtime = message.readUnsignedShort(); |
| 132 | if ((remoteHoldtime != 0) && |
| 133 | (remoteHoldtime < BgpConstants.BGP_KEEPALIVE_MIN_HOLDTIME)) { |
| 134 | log.debug("BGP RX OPEN Error from {}: " + |
| 135 | "Unacceptable Hold Time field {}. " + |
| 136 | "Should be 0 or at least {}", |
| 137 | bgpSession.getRemoteAddress(), remoteHoldtime, |
| 138 | BgpConstants.BGP_KEEPALIVE_MIN_HOLDTIME); |
| 139 | // |
| 140 | // ERROR: Unacceptable Hold Time |
| 141 | // |
| 142 | // Send NOTIFICATION and close the connection |
| 143 | int errorCode = OpenMessageError.ERROR_CODE; |
| 144 | int errorSubcode = OpenMessageError.UNACCEPTABLE_HOLD_TIME; |
| 145 | ChannelBuffer txMessage = |
| 146 | BgpNotification.prepareBgpNotification(errorCode, errorSubcode, |
| 147 | null); |
| 148 | ctx.getChannel().write(txMessage); |
| 149 | bgpSession.closeSession(ctx); |
| 150 | return; |
| 151 | } |
| 152 | bgpSession.setRemoteHoldtime(remoteHoldtime); |
| 153 | |
| 154 | // Remote BGP Identifier |
| 155 | Ip4Address remoteBgpId = |
| 156 | Ip4Address.valueOf((int) message.readUnsignedInt()); |
| 157 | bgpSession.setRemoteBgpId(remoteBgpId); |
| 158 | |
Pavlin Radoslavov | 278cdde | 2014-12-16 14:09:31 -0800 | [diff] [blame] | 159 | // Parse the Optional Parameters |
| 160 | try { |
| 161 | parseOptionalParameters(bgpSession, ctx, message); |
| 162 | } catch (BgpParseException e) { |
| 163 | // ERROR: Error parsing optional parameters |
Pavlin Radoslavov | 80f3e18 | 2014-12-15 10:46:18 -0800 | [diff] [blame] | 164 | log.debug("BGP RX OPEN Error from {}: " + |
Pavlin Radoslavov | 278cdde | 2014-12-16 14:09:31 -0800 | [diff] [blame] | 165 | "Exception parsing Optional Parameters: {}", |
| 166 | bgpSession.getRemoteAddress(), e); |
Pavlin Radoslavov | 80f3e18 | 2014-12-15 10:46:18 -0800 | [diff] [blame] | 167 | // |
Pavlin Radoslavov | 278cdde | 2014-12-16 14:09:31 -0800 | [diff] [blame] | 168 | // ERROR: Invalid Optional Parameters: Unspecific |
Pavlin Radoslavov | 80f3e18 | 2014-12-15 10:46:18 -0800 | [diff] [blame] | 169 | // |
| 170 | // Send NOTIFICATION and close the connection |
| 171 | int errorCode = OpenMessageError.ERROR_CODE; |
| 172 | int errorSubcode = Notifications.ERROR_SUBCODE_UNSPECIFIC; |
| 173 | ChannelBuffer txMessage = |
| 174 | BgpNotification.prepareBgpNotification(errorCode, errorSubcode, |
| 175 | null); |
| 176 | ctx.getChannel().write(txMessage); |
| 177 | bgpSession.closeSession(ctx); |
| 178 | return; |
| 179 | } |
Pavlin Radoslavov | 80f3e18 | 2014-12-15 10:46:18 -0800 | [diff] [blame] | 180 | |
| 181 | log.debug("BGP RX OPEN message from {}: " + |
| 182 | "BGPv{} AS {} BGP-ID {} Holdtime {}", |
| 183 | bgpSession.getRemoteAddress(), remoteBgpVersion, remoteAs, |
| 184 | remoteBgpId, remoteHoldtime); |
| 185 | |
| 186 | // Send my OPEN followed by KEEPALIVE |
| 187 | ChannelBuffer txMessage = prepareBgpOpen(bgpSession); |
| 188 | ctx.getChannel().write(txMessage); |
| 189 | // |
| 190 | txMessage = BgpKeepalive.prepareBgpKeepalive(); |
| 191 | ctx.getChannel().write(txMessage); |
| 192 | |
| 193 | // Start the KEEPALIVE timer |
| 194 | bgpSession.restartKeepaliveTimer(ctx); |
| 195 | |
| 196 | // Start the Session Timeout timer |
| 197 | bgpSession.restartSessionTimeoutTimer(ctx); |
| 198 | } |
| 199 | |
| 200 | /** |
| 201 | * Prepares BGP OPEN message. |
| 202 | * |
| 203 | * @param bgpSession the BGP Session to use |
| 204 | * @return the message to transmit (BGP header included) |
| 205 | */ |
| 206 | private static ChannelBuffer prepareBgpOpen(BgpSession bgpSession) { |
| 207 | ChannelBuffer message = |
| 208 | ChannelBuffers.buffer(BgpConstants.BGP_MESSAGE_MAX_LENGTH); |
| 209 | |
| 210 | // |
| 211 | // Prepare the OPEN message payload |
| 212 | // |
| 213 | message.writeByte(bgpSession.getLocalBgpVersion()); |
| 214 | message.writeShort((int) bgpSession.getLocalAs()); |
| 215 | message.writeShort((int) bgpSession.getLocalHoldtime()); |
| 216 | message.writeInt(bgpSession.getLocalBgpId().toInt()); |
Pavlin Radoslavov | 278cdde | 2014-12-16 14:09:31 -0800 | [diff] [blame] | 217 | |
| 218 | // Prepare the optional BGP Capabilities |
| 219 | ChannelBuffer capabilitiesMessage = |
| 220 | prepareBgpOpenCapabilities(bgpSession); |
| 221 | message.writeByte(capabilitiesMessage.readableBytes()); |
| 222 | message.writeBytes(capabilitiesMessage); |
| 223 | |
Pavlin Radoslavov | 80f3e18 | 2014-12-15 10:46:18 -0800 | [diff] [blame] | 224 | return BgpMessage.prepareBgpMessage(BgpConstants.BGP_TYPE_OPEN, |
| 225 | message); |
| 226 | } |
Pavlin Radoslavov | 278cdde | 2014-12-16 14:09:31 -0800 | [diff] [blame] | 227 | |
| 228 | /** |
| 229 | * Parses BGP OPEN Optional Parameters. |
| 230 | * |
| 231 | * @param bgpSession the BGP Session to use |
| 232 | * @param ctx the Channel Handler Context |
| 233 | * @param message the message to process |
| 234 | * @throws BgpParseException |
| 235 | */ |
| 236 | private static void parseOptionalParameters(BgpSession bgpSession, |
| 237 | ChannelHandlerContext ctx, |
| 238 | ChannelBuffer message) |
| 239 | throws BgpParseException { |
| 240 | |
| 241 | // |
| 242 | // Get and verify the Optional Parameters Length |
| 243 | // |
| 244 | int optParamLength = message.readUnsignedByte(); |
| 245 | if (optParamLength > message.readableBytes()) { |
| 246 | // ERROR: Invalid Optional Parameter Length |
| 247 | String errorMsg = "Invalid Optional Parameter Length field " + |
| 248 | optParamLength + ". Remaining Optional Parameters " + |
| 249 | message.readableBytes(); |
| 250 | throw new BgpParseException(errorMsg); |
| 251 | } |
| 252 | if (optParamLength == 0) { |
| 253 | return; // No Optional Parameters |
| 254 | } |
| 255 | |
| 256 | // |
| 257 | // Parse the Optional Parameters |
| 258 | // |
| 259 | int optParamEnd = message.readerIndex() + optParamLength; |
| 260 | while (message.readerIndex() < optParamEnd) { |
| 261 | int paramType = message.readUnsignedByte(); |
| 262 | if (message.readerIndex() >= optParamEnd) { |
| 263 | // ERROR: Malformed Optional Parameters |
| 264 | String errorMsg = "Malformed Optional Parameters"; |
| 265 | throw new BgpParseException(errorMsg); |
| 266 | } |
| 267 | int paramLen = message.readUnsignedByte(); |
| 268 | if (message.readerIndex() + paramLen > optParamEnd) { |
| 269 | // ERROR: Malformed Optional Parameters |
| 270 | String errorMsg = "Malformed Optional Parameters"; |
| 271 | throw new BgpParseException(errorMsg); |
| 272 | } |
| 273 | |
| 274 | // |
| 275 | // Extract the Optional Parameter Value based on the Parameter Type |
| 276 | // |
| 277 | switch (paramType) { |
| 278 | case Capabilities.TYPE: |
| 279 | // Optional Parameter Type: Capabilities |
| 280 | if (paramLen < Capabilities.MIN_LENGTH) { |
| 281 | // ERROR: Malformed Capability |
| 282 | String errorMsg = "Malformed Capability Type " + paramType; |
| 283 | throw new BgpParseException(errorMsg); |
| 284 | } |
| 285 | int capabEnd = message.readerIndex() + paramLen; |
| 286 | int capabCode = message.readUnsignedByte(); |
| 287 | int capabLen = message.readUnsignedByte(); |
| 288 | if (message.readerIndex() + capabLen > capabEnd) { |
| 289 | // ERROR: Malformed Capability |
| 290 | String errorMsg = "Malformed Capability Type " + paramType; |
| 291 | throw new BgpParseException(errorMsg); |
| 292 | } |
| 293 | |
| 294 | switch (capabCode) { |
| 295 | case MultiprotocolExtensions.CODE: |
| 296 | // Multiprotocol Extensions Capabilities (RFC 4760) |
| 297 | if (capabLen != MultiprotocolExtensions.LENGTH) { |
| 298 | // ERROR: Multiprotocol Extension Length Error |
| 299 | String errorMsg = "Multiprotocol Extension Length Error"; |
| 300 | throw new BgpParseException(errorMsg); |
| 301 | } |
| 302 | // Decode the AFI (2 octets) and SAFI (1 octet) |
| 303 | int afi = message.readUnsignedShort(); |
| 304 | int reserved = message.readUnsignedByte(); |
| 305 | int safi = message.readUnsignedByte(); |
| 306 | log.debug("BGP RX OPEN Capability: AFI = {} SAFI = {}", |
| 307 | afi, safi); |
| 308 | // |
| 309 | // Setup the AFI/SAFI in the BgpSession |
| 310 | // |
| 311 | if (afi == MultiprotocolExtensions.AFI_IPV4 && |
| 312 | safi == MultiprotocolExtensions.SAFI_UNICAST) { |
| 313 | bgpSession.setRemoteIpv4Unicast(); |
| 314 | } else if (afi == MultiprotocolExtensions.AFI_IPV4 && |
| 315 | safi == MultiprotocolExtensions.SAFI_MULTICAST) { |
| 316 | bgpSession.setRemoteIpv4Multicast(); |
| 317 | } else if (afi == MultiprotocolExtensions.AFI_IPV6 && |
| 318 | safi == MultiprotocolExtensions.SAFI_UNICAST) { |
| 319 | bgpSession.setRemoteIpv6Unicast(); |
| 320 | } else if (afi == MultiprotocolExtensions.AFI_IPV6 && |
| 321 | safi == MultiprotocolExtensions.SAFI_MULTICAST) { |
| 322 | bgpSession.setRemoteIpv6Multicast(); |
| 323 | } else { |
| 324 | log.debug("BGP RX OPEN Capability: Unknown AFI = {} SAFI = {}", |
| 325 | afi, safi); |
| 326 | } |
| 327 | break; |
| 328 | |
| 329 | case Capabilities.As4Octet.CODE: |
| 330 | // Support for 4-octet AS Number Capabilities (RFC 6793) |
| 331 | if (capabLen != Capabilities.As4Octet.LENGTH) { |
| 332 | // ERROR: 4-octet AS Number Capability Length Error |
| 333 | String errorMsg = "4-octet AS Number Capability Length Error"; |
| 334 | throw new BgpParseException(errorMsg); |
| 335 | } |
| 336 | long as4Number = message.readUnsignedInt(); |
| 337 | // TODO: Implement support for 4-octet AS Numbers |
| 338 | log.debug("BGP RX OPEN Capability: AS4 Number = {}", |
| 339 | as4Number); |
| 340 | break; |
| 341 | |
| 342 | default: |
| 343 | // Unknown Capability: ignore it |
| 344 | log.debug("BGP RX OPEN Capability Code = {} Length = {}", |
| 345 | capabCode, capabLen); |
| 346 | message.readBytes(capabLen); |
| 347 | break; |
| 348 | } |
| 349 | |
| 350 | break; |
| 351 | |
| 352 | default: |
| 353 | // Unknown Parameter Type: ignore it |
| 354 | log.debug("BGP RX OPEN Parameter Type = {} Length = {}", |
| 355 | paramType, paramLen); |
| 356 | message.readBytes(paramLen); |
| 357 | break; |
| 358 | } |
| 359 | } |
| 360 | } |
| 361 | |
| 362 | /** |
| 363 | * Prepares the Capabilities for the BGP OPEN message. |
| 364 | * |
| 365 | * @param bgpSession the BGP Session to use |
| 366 | * @return the buffer with the BGP Capabilities to transmit |
| 367 | */ |
| 368 | private static ChannelBuffer prepareBgpOpenCapabilities( |
| 369 | BgpSession bgpSession) { |
| 370 | ChannelBuffer message = |
| 371 | ChannelBuffers.buffer(BgpConstants.BGP_MESSAGE_MAX_LENGTH); |
| 372 | |
| 373 | // |
| 374 | // Write the Multiprotocol Extensions Capabilities |
| 375 | // |
| 376 | |
| 377 | // IPv4 unicast |
| 378 | if (bgpSession.getLocalIpv4Unicast()) { |
| 379 | message.writeByte(Capabilities.TYPE); // Param type |
| 380 | message.writeByte(Capabilities.MIN_LENGTH + |
| 381 | MultiprotocolExtensions.LENGTH); // Param len |
| 382 | message.writeByte(MultiprotocolExtensions.CODE); // Capab. code |
| 383 | message.writeByte(MultiprotocolExtensions.LENGTH); // Capab. len |
| 384 | message.writeShort(MultiprotocolExtensions.AFI_IPV4); |
| 385 | message.writeByte(0); // Reserved field |
| 386 | message.writeByte(MultiprotocolExtensions.SAFI_UNICAST); |
| 387 | } |
| 388 | // IPv4 multicast |
| 389 | if (bgpSession.getLocalIpv4Multicast()) { |
| 390 | message.writeByte(Capabilities.TYPE); // Param type |
| 391 | message.writeByte(Capabilities.MIN_LENGTH + |
| 392 | MultiprotocolExtensions.LENGTH); // Param len |
| 393 | message.writeByte(MultiprotocolExtensions.CODE); // Capab. code |
| 394 | message.writeByte(MultiprotocolExtensions.LENGTH); // Capab. len |
| 395 | message.writeShort(MultiprotocolExtensions.AFI_IPV4); |
| 396 | message.writeByte(0); // Reserved field |
| 397 | message.writeByte(MultiprotocolExtensions.SAFI_MULTICAST); |
| 398 | } |
| 399 | // IPv6 unicast |
| 400 | if (bgpSession.getLocalIpv6Unicast()) { |
| 401 | message.writeByte(Capabilities.TYPE); // Param type |
| 402 | message.writeByte(Capabilities.MIN_LENGTH + |
| 403 | MultiprotocolExtensions.LENGTH); // Param len |
| 404 | message.writeByte(MultiprotocolExtensions.CODE); // Capab. code |
| 405 | message.writeByte(MultiprotocolExtensions.LENGTH); // Capab. len |
| 406 | message.writeShort(MultiprotocolExtensions.AFI_IPV6); |
| 407 | message.writeByte(0); // Reserved field |
| 408 | message.writeByte(MultiprotocolExtensions.SAFI_UNICAST); |
| 409 | } |
| 410 | // IPv6 multicast |
| 411 | if (bgpSession.getLocalIpv6Multicast()) { |
| 412 | message.writeByte(Capabilities.TYPE); // Param type |
| 413 | message.writeByte(Capabilities.MIN_LENGTH + |
| 414 | MultiprotocolExtensions.LENGTH); // Param len |
| 415 | message.writeByte(MultiprotocolExtensions.CODE); // Capab. code |
| 416 | message.writeByte(MultiprotocolExtensions.LENGTH); // Capab. len |
| 417 | message.writeShort(MultiprotocolExtensions.AFI_IPV6); |
| 418 | message.writeByte(0); // Reserved field |
| 419 | message.writeByte(MultiprotocolExtensions.SAFI_MULTICAST); |
| 420 | } |
| 421 | |
| 422 | return message; |
| 423 | } |
Pavlin Radoslavov | 80f3e18 | 2014-12-15 10:46:18 -0800 | [diff] [blame] | 424 | } |