| /* |
| * 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.onlab.packet.Ip4Address; |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| /** |
| * A class for handling BGP OPEN messages. |
| */ |
| final class BgpOpen { |
| private static final Logger log = LoggerFactory.getLogger(BgpOpen.class); |
| |
| /** |
| * Default constructor. |
| * <p> |
| * The constructor is private to prevent creating an instance of |
| * this utility class. |
| */ |
| private BgpOpen() { |
| } |
| |
| /** |
| * Processes BGP OPEN message. |
| * |
| * @param bgpSession the BGP Session to use |
| * @param ctx the Channel Handler Context |
| * @param message the message to process |
| */ |
| static void processBgpOpen(BgpSession bgpSession, |
| ChannelHandlerContext ctx, |
| ChannelBuffer message) { |
| int minLength = |
| BgpConstants.BGP_OPEN_MIN_LENGTH - BgpConstants.BGP_HEADER_LENGTH; |
| if (message.readableBytes() < minLength) { |
| log.debug("BGP RX OPEN Error from {}: " + |
| "Message length {} too short. Must be at least {}", |
| bgpSession.remoteInfo().address(), |
| message.readableBytes(), minLength); |
| // |
| // ERROR: Bad Message Length |
| // |
| // Send NOTIFICATION and close the connection |
| ChannelBuffer txMessage = |
| BgpNotification.prepareBgpNotificationBadMessageLength( |
| message.readableBytes() + BgpConstants.BGP_HEADER_LENGTH); |
| ctx.getChannel().write(txMessage); |
| bgpSession.closeSession(ctx); |
| return; |
| } |
| |
| // |
| // Parse the OPEN message |
| // |
| // Remote BGP version |
| int remoteBgpVersion = message.readUnsignedByte(); |
| if (remoteBgpVersion != BgpConstants.BGP_VERSION) { |
| log.debug("BGP RX OPEN Error from {}: " + |
| "Unsupported BGP version {}. Should be {}", |
| bgpSession.remoteInfo().address(), remoteBgpVersion, |
| BgpConstants.BGP_VERSION); |
| // |
| // ERROR: Unsupported Version Number |
| // |
| // Send NOTIFICATION and close the connection |
| int errorCode = BgpConstants.Notifications.OpenMessageError.ERROR_CODE; |
| int errorSubcode = BgpConstants.Notifications.OpenMessageError.UNSUPPORTED_VERSION_NUMBER; |
| ChannelBuffer data = ChannelBuffers.buffer(2); |
| data.writeShort(BgpConstants.BGP_VERSION); |
| ChannelBuffer txMessage = |
| BgpNotification.prepareBgpNotification(errorCode, errorSubcode, |
| data); |
| ctx.getChannel().write(txMessage); |
| bgpSession.closeSession(ctx); |
| return; |
| } |
| bgpSession.remoteInfo().setBgpVersion(remoteBgpVersion); |
| |
| // Remote AS number |
| long remoteAs = message.readUnsignedShort(); |
| bgpSession.remoteInfo().setAsNumber(remoteAs); |
| // |
| // NOTE: Currently, the local AS number is always set to the remote AS. |
| // This is done, because the peer setup is always iBGP. |
| // In the future, the local AS number should be configured as part |
| // of an explicit BGP peering configuration. |
| // |
| bgpSession.localInfo().setAsNumber(remoteAs); |
| |
| // Remote Hold Time |
| long remoteHoldtime = message.readUnsignedShort(); |
| if ((remoteHoldtime != 0) && |
| (remoteHoldtime < BgpConstants.BGP_KEEPALIVE_MIN_HOLDTIME)) { |
| log.debug("BGP RX OPEN Error from {}: " + |
| "Unacceptable Hold Time field {}. " + |
| "Should be 0 or at least {}", |
| bgpSession.remoteInfo().address(), remoteHoldtime, |
| BgpConstants.BGP_KEEPALIVE_MIN_HOLDTIME); |
| // |
| // ERROR: Unacceptable Hold Time |
| // |
| // Send NOTIFICATION and close the connection |
| int errorCode = BgpConstants.Notifications.OpenMessageError.ERROR_CODE; |
| int errorSubcode = BgpConstants.Notifications.OpenMessageError.UNACCEPTABLE_HOLD_TIME; |
| ChannelBuffer txMessage = |
| BgpNotification.prepareBgpNotification(errorCode, errorSubcode, |
| null); |
| ctx.getChannel().write(txMessage); |
| bgpSession.closeSession(ctx); |
| return; |
| } |
| bgpSession.remoteInfo().setHoldtime(remoteHoldtime); |
| // |
| // NOTE: Currently. the local BGP Holdtime is always set to the remote |
| // BGP holdtime. |
| // In the future, the local BGP Holdtime should be configured as part |
| // of an explicit BGP peering configuration. |
| // |
| bgpSession.localInfo().setHoldtime(remoteHoldtime); |
| |
| // Remote BGP Identifier |
| Ip4Address remoteBgpId = |
| Ip4Address.valueOf((int) message.readUnsignedInt()); |
| bgpSession.remoteInfo().setBgpId(remoteBgpId); |
| |
| // Parse the Optional Parameters |
| try { |
| parseOptionalParameters(bgpSession, ctx, message); |
| } catch (BgpMessage.BgpParseException e) { |
| // ERROR: Error parsing optional parameters |
| log.debug("BGP RX OPEN Error from {}: " + |
| "Exception parsing Optional Parameters: {}", |
| bgpSession.remoteInfo().address(), e); |
| // |
| // ERROR: Invalid Optional Parameters: Unspecific |
| // |
| // Send NOTIFICATION and close the connection |
| int errorCode = BgpConstants.Notifications.OpenMessageError.ERROR_CODE; |
| int errorSubcode = BgpConstants.Notifications.ERROR_SUBCODE_UNSPECIFIC; |
| ChannelBuffer txMessage = |
| BgpNotification.prepareBgpNotification(errorCode, errorSubcode, |
| null); |
| ctx.getChannel().write(txMessage); |
| bgpSession.closeSession(ctx); |
| return; |
| } |
| |
| // |
| // NOTE: Prepare the BGP OPEN message before the original local AS |
| // is overwritten by the 4-octet AS number |
| // |
| ChannelBuffer txOpenMessage = prepareBgpOpen(bgpSession.localInfo()); |
| |
| // |
| // Use the 4-octet AS number in lieu of the "My AS" field |
| // See RFC 6793, Section 4.1, second paragraph. |
| // |
| if (bgpSession.remoteInfo().as4OctetCapability()) { |
| long as4Number = bgpSession.remoteInfo().as4Number(); |
| bgpSession.remoteInfo().setAsNumber(as4Number); |
| bgpSession.localInfo().setAsNumber(as4Number); |
| } |
| |
| // |
| // Verify that the AS number is same for all other BGP Sessions |
| // NOTE: This check applies only for our use-case where all BGP |
| // sessions are iBGP. |
| // |
| for (BgpSession bs : bgpSession.getBgpSessionManager().getBgpSessions()) { |
| if ((bs.remoteInfo().asNumber() != 0) && |
| (bgpSession.remoteInfo().asNumber() != |
| bs.remoteInfo().asNumber())) { |
| log.debug("BGP RX OPEN Error from {}: Bad Peer AS {}. " + |
| "Expected {}", |
| bgpSession.remoteInfo().address(), |
| bgpSession.remoteInfo().asNumber(), |
| bs.remoteInfo().asNumber()); |
| // |
| // ERROR: Bad Peer AS |
| // |
| // Send NOTIFICATION and close the connection |
| int errorCode = BgpConstants.Notifications.OpenMessageError.ERROR_CODE; |
| int errorSubcode = BgpConstants.Notifications.OpenMessageError.BAD_PEER_AS; |
| ChannelBuffer txMessage = |
| BgpNotification.prepareBgpNotification(errorCode, |
| errorSubcode, null); |
| ctx.getChannel().write(txMessage); |
| bgpSession.closeSession(ctx); |
| return; |
| } |
| } |
| |
| log.debug("BGP RX OPEN message from {}: " + |
| "BGPv{} AS {} BGP-ID {} Holdtime {}", |
| bgpSession.remoteInfo().address(), |
| bgpSession.remoteInfo().bgpVersion(), |
| bgpSession.remoteInfo().asNumber(), |
| bgpSession.remoteInfo().bgpId(), |
| bgpSession.remoteInfo().holdtime()); |
| |
| // Send my OPEN followed by KEEPALIVE |
| ctx.getChannel().write(txOpenMessage); |
| // |
| ChannelBuffer txMessage = BgpKeepalive.prepareBgpKeepalive(); |
| ctx.getChannel().write(txMessage); |
| |
| // Start the KEEPALIVE timer |
| bgpSession.restartKeepaliveTimer(ctx); |
| |
| // Start the Session Timeout timer |
| bgpSession.restartSessionTimeoutTimer(ctx); |
| } |
| |
| /** |
| * Prepares BGP OPEN message. |
| * |
| * @param localInfo the BGP Session local information to use |
| * @return the message to transmit (BGP header included) |
| */ |
| static ChannelBuffer prepareBgpOpen(BgpSessionInfo localInfo) { |
| ChannelBuffer message = |
| ChannelBuffers.buffer(BgpConstants.BGP_MESSAGE_MAX_LENGTH); |
| |
| // |
| // Prepare the OPEN message payload |
| // |
| message.writeByte(localInfo.bgpVersion()); |
| message.writeShort((int) localInfo.asNumber()); |
| message.writeShort((int) localInfo.holdtime()); |
| message.writeInt(localInfo.bgpId().toInt()); |
| |
| // Prepare the optional BGP Capabilities |
| ChannelBuffer capabilitiesMessage = |
| prepareBgpOpenCapabilities(localInfo); |
| message.writeByte(capabilitiesMessage.readableBytes()); |
| message.writeBytes(capabilitiesMessage); |
| |
| return BgpMessage.prepareBgpMessage(BgpConstants.BGP_TYPE_OPEN, |
| message); |
| } |
| |
| /** |
| * Parses BGP OPEN Optional Parameters. |
| * |
| * @param bgpSession the BGP Session to use |
| * @param ctx the Channel Handler Context |
| * @param message the message to process |
| * @throws BgpMessage.BgpParseException |
| */ |
| private static void parseOptionalParameters(BgpSession bgpSession, |
| ChannelHandlerContext ctx, |
| ChannelBuffer message) |
| throws BgpMessage.BgpParseException { |
| |
| // |
| // Get and verify the Optional Parameters Length |
| // |
| int optParamLength = message.readUnsignedByte(); |
| if (optParamLength > message.readableBytes()) { |
| // ERROR: Invalid Optional Parameter Length |
| String errorMsg = "Invalid Optional Parameter Length field " + |
| optParamLength + ". Remaining Optional Parameters " + |
| message.readableBytes(); |
| throw new BgpMessage.BgpParseException(errorMsg); |
| } |
| if (optParamLength == 0) { |
| return; // No Optional Parameters |
| } |
| |
| // |
| // Parse the Optional Parameters |
| // |
| int optParamEnd = message.readerIndex() + optParamLength; |
| while (message.readerIndex() < optParamEnd) { |
| int paramType = message.readUnsignedByte(); |
| if (message.readerIndex() >= optParamEnd) { |
| // ERROR: Malformed Optional Parameters |
| String errorMsg = "Malformed Optional Parameters"; |
| throw new BgpMessage.BgpParseException(errorMsg); |
| } |
| int paramLen = message.readUnsignedByte(); |
| if (message.readerIndex() + paramLen > optParamEnd) { |
| // ERROR: Malformed Optional Parameters |
| String errorMsg = "Malformed Optional Parameters"; |
| throw new BgpMessage.BgpParseException(errorMsg); |
| } |
| |
| // |
| // Extract the Optional Parameter Value based on the Parameter Type |
| // |
| switch (paramType) { |
| case BgpConstants.Open.Capabilities.TYPE: |
| // Optional Parameter Type: Capabilities |
| if (paramLen < BgpConstants.Open.Capabilities.MIN_LENGTH) { |
| // ERROR: Malformed Param Type |
| String errorMsg = "Malformed Capabilities Optional " |
| + "Parameter Type " + paramType; |
| throw new BgpMessage.BgpParseException(errorMsg); |
| } |
| int paramEnd = message.readerIndex() + paramLen; |
| // Parse Capabilities |
| while (message.readerIndex() < paramEnd) { |
| if (paramEnd - message.readerIndex() < |
| BgpConstants.Open.Capabilities.MIN_LENGTH) { |
| String errorMsg = "Malformed Capabilities"; |
| throw new BgpMessage.BgpParseException(errorMsg); |
| } |
| int capabCode = message.readUnsignedByte(); |
| int capabLen = message.readUnsignedByte(); |
| if (message.readerIndex() + capabLen > paramEnd) { |
| // ERROR: Malformed Capability |
| String errorMsg = "Malformed Capability instance with " |
| + "code " + capabCode; |
| throw new BgpMessage.BgpParseException(errorMsg); |
| } |
| |
| switch (capabCode) { |
| case BgpConstants.Open.Capabilities.MultiprotocolExtensions.CODE: |
| // Multiprotocol Extensions Capabilities (RFC 4760) |
| if (capabLen != BgpConstants.Open.Capabilities.MultiprotocolExtensions.LENGTH) { |
| // ERROR: Multiprotocol Extension Length Error |
| String errorMsg = "Multiprotocol Extension Length Error"; |
| throw new BgpMessage.BgpParseException(errorMsg); |
| } |
| // Decode the AFI (2 octets) and SAFI (1 octet) |
| int afi = message.readUnsignedShort(); |
| int reserved = message.readUnsignedByte(); |
| int safi = message.readUnsignedByte(); |
| log.debug("BGP RX OPEN Capability: AFI = {} SAFI = {}", |
| afi, safi); |
| // |
| // Setup the AFI/SAFI in the BgpSession |
| // |
| // NOTE: For now we just copy the remote AFI/SAFI setting |
| // to the local configuration. |
| // |
| if (afi == BgpConstants.Open.Capabilities.MultiprotocolExtensions.AFI_IPV4 && |
| safi == BgpConstants.Open.Capabilities.MultiprotocolExtensions.SAFI_UNICAST) { |
| bgpSession.remoteInfo().setIpv4Unicast(); |
| bgpSession.localInfo().setIpv4Unicast(); |
| } else if (afi == BgpConstants.Open.Capabilities.MultiprotocolExtensions.AFI_IPV4 && |
| safi == BgpConstants.Open.Capabilities.MultiprotocolExtensions.SAFI_MULTICAST) { |
| bgpSession.remoteInfo().setIpv4Multicast(); |
| bgpSession.localInfo().setIpv4Multicast(); |
| } else if (afi == BgpConstants.Open.Capabilities.MultiprotocolExtensions.AFI_IPV6 && |
| safi == BgpConstants.Open.Capabilities.MultiprotocolExtensions.SAFI_UNICAST) { |
| bgpSession.remoteInfo().setIpv6Unicast(); |
| bgpSession.localInfo().setIpv6Unicast(); |
| } else if (afi == BgpConstants.Open.Capabilities.MultiprotocolExtensions.AFI_IPV6 && |
| safi == BgpConstants.Open.Capabilities.MultiprotocolExtensions.SAFI_MULTICAST) { |
| bgpSession.remoteInfo().setIpv6Multicast(); |
| bgpSession.localInfo().setIpv6Multicast(); |
| } else { |
| log.debug("BGP RX OPEN Capability: Unknown AFI = {} SAFI = {}", |
| afi, safi); |
| } |
| break; |
| |
| case BgpConstants.Open.Capabilities.As4Octet.CODE: |
| // Support for 4-octet AS Number Capabilities (RFC 6793) |
| if (capabLen != BgpConstants.Open.Capabilities.As4Octet.LENGTH) { |
| // ERROR: 4-octet AS Number Capability Length Error |
| String errorMsg = "4-octet AS Number Capability Length Error"; |
| throw new BgpMessage.BgpParseException(errorMsg); |
| } |
| long as4Number = message.readUnsignedInt(); |
| |
| bgpSession.remoteInfo().setAs4OctetCapability(); |
| bgpSession.remoteInfo().setAs4Number(as4Number); |
| |
| // |
| // Copy remote 4-octet AS Number Capabilities and AS |
| // Number. This is a temporary setting until local AS |
| // number configuration is supported. |
| // |
| bgpSession.localInfo().setAs4OctetCapability(); |
| bgpSession.localInfo().setAs4Number(as4Number); |
| log.debug("BGP RX OPEN Capability: AS4 Number = {}", |
| as4Number); |
| break; |
| |
| default: |
| // Unknown Capability: ignore it |
| log.debug("BGP RX OPEN Capability Code = {} Length = {}", |
| capabCode, capabLen); |
| message.readBytes(capabLen); |
| break; |
| } |
| |
| |
| } |
| break; |
| default: |
| // Unknown Parameter Type: ignore it |
| log.debug("BGP RX OPEN Parameter Type = {} Length = {}", |
| paramType, paramLen); |
| message.readBytes(paramLen); |
| break; |
| } |
| } |
| } |
| |
| /** |
| * Prepares the Capabilities for the BGP OPEN message. |
| * |
| * @param localInfo the BGP Session local information to use |
| * @return the buffer with the BGP Capabilities to transmit |
| */ |
| private static ChannelBuffer prepareBgpOpenCapabilities( |
| BgpSessionInfo localInfo) { |
| ChannelBuffer message = |
| ChannelBuffers.buffer(BgpConstants.BGP_MESSAGE_MAX_LENGTH); |
| |
| // |
| // Write the Multiprotocol Extensions Capabilities |
| // |
| |
| // IPv4 unicast |
| if (localInfo.ipv4Unicast()) { |
| message.writeByte(BgpConstants.Open.Capabilities.TYPE); // Param type |
| message.writeByte(BgpConstants.Open.Capabilities.MIN_LENGTH + |
| BgpConstants.Open.Capabilities.MultiprotocolExtensions.LENGTH); // Param len |
| message.writeByte( |
| BgpConstants.Open.Capabilities.MultiprotocolExtensions.CODE); // Capab. code |
| message.writeByte( |
| BgpConstants.Open.Capabilities.MultiprotocolExtensions.LENGTH); // Capab. len |
| message.writeShort( |
| BgpConstants.Open.Capabilities.MultiprotocolExtensions.AFI_IPV4); |
| message.writeByte(0); // Reserved field |
| message.writeByte( |
| BgpConstants.Open.Capabilities.MultiprotocolExtensions.SAFI_UNICAST); |
| } |
| // IPv4 multicast |
| if (localInfo.ipv4Multicast()) { |
| message.writeByte(BgpConstants.Open.Capabilities.TYPE); // Param type |
| message.writeByte(BgpConstants.Open.Capabilities.MIN_LENGTH + |
| BgpConstants.Open.Capabilities.MultiprotocolExtensions.LENGTH); // Param len |
| message.writeByte( |
| BgpConstants.Open.Capabilities.MultiprotocolExtensions.CODE); // Capab. code |
| message.writeByte( |
| BgpConstants.Open.Capabilities.MultiprotocolExtensions.LENGTH); // Capab. len |
| message.writeShort( |
| BgpConstants.Open.Capabilities.MultiprotocolExtensions.AFI_IPV4); |
| message.writeByte(0); // Reserved field |
| message.writeByte( |
| BgpConstants.Open.Capabilities.MultiprotocolExtensions.SAFI_MULTICAST); |
| } |
| // IPv6 unicast |
| if (localInfo.ipv6Unicast()) { |
| message.writeByte(BgpConstants.Open.Capabilities.TYPE); // Param type |
| message.writeByte(BgpConstants.Open.Capabilities.MIN_LENGTH + |
| BgpConstants.Open.Capabilities.MultiprotocolExtensions.LENGTH); // Param len |
| message.writeByte( |
| BgpConstants.Open.Capabilities.MultiprotocolExtensions.CODE); // Capab. code |
| message.writeByte( |
| BgpConstants.Open.Capabilities.MultiprotocolExtensions.LENGTH); // Capab. len |
| message.writeShort( |
| BgpConstants.Open.Capabilities.MultiprotocolExtensions.AFI_IPV6); |
| message.writeByte(0); // Reserved field |
| message.writeByte( |
| BgpConstants.Open.Capabilities.MultiprotocolExtensions.SAFI_UNICAST); |
| } |
| // IPv6 multicast |
| if (localInfo.ipv6Multicast()) { |
| message.writeByte(BgpConstants.Open.Capabilities.TYPE); // Param type |
| message.writeByte(BgpConstants.Open.Capabilities.MIN_LENGTH + |
| BgpConstants.Open.Capabilities.MultiprotocolExtensions.LENGTH); // Param len |
| message.writeByte( |
| BgpConstants.Open.Capabilities.MultiprotocolExtensions.CODE); // Capab. code |
| message.writeByte( |
| BgpConstants.Open.Capabilities.MultiprotocolExtensions.LENGTH); // Capab. len |
| message.writeShort( |
| BgpConstants.Open.Capabilities.MultiprotocolExtensions.AFI_IPV6); |
| message.writeByte(0); // Reserved field |
| message.writeByte( |
| BgpConstants.Open.Capabilities.MultiprotocolExtensions.SAFI_MULTICAST); |
| } |
| |
| // 4 octet AS path capability |
| if (localInfo.as4OctetCapability()) { |
| message.writeByte(BgpConstants.Open.Capabilities.TYPE); // Param type |
| message.writeByte(BgpConstants.Open.Capabilities.MIN_LENGTH + |
| BgpConstants.Open.Capabilities.As4Octet.LENGTH); // Param len |
| message.writeByte(BgpConstants.Open.Capabilities.As4Octet.CODE); // Capab. code |
| message.writeByte(BgpConstants.Open.Capabilities.As4Octet.LENGTH); // Capab. len |
| message.writeInt((int) localInfo.as4Number()); |
| } |
| return message; |
| } |
| } |