| /* |
| * Copyright 2014 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.sdnip.bgp; |
| |
| import java.util.ArrayList; |
| import java.util.Collection; |
| import java.util.HashMap; |
| import java.util.Map; |
| |
| import org.apache.commons.lang3.tuple.Pair; |
| 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.onlab.packet.Ip4Prefix; |
| import org.onosproject.sdnip.bgp.BgpConstants.Update.AsPath; |
| import org.onosproject.sdnip.bgp.BgpConstants.Notifications.UpdateMessageError; |
| import org.onosproject.sdnip.bgp.BgpMessage.BgpParseException; |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| /** |
| * A class for handling BGP UPDATE messages. |
| */ |
| final class BgpUpdate { |
| private static final Logger log = LoggerFactory.getLogger(BgpUpdate.class); |
| |
| /** |
| * Default constructor. |
| * <p> |
| * The constructor is private to prevent creating an instance of |
| * this utility class. |
| */ |
| private BgpUpdate() { |
| } |
| |
| /** |
| * Processes BGP UPDATE message. |
| * |
| * @param bgpSession the BGP Session to use |
| * @param ctx the Channel Handler Context |
| * @param message the message to process |
| */ |
| static void processBgpUpdate(BgpSession bgpSession, |
| ChannelHandlerContext ctx, |
| ChannelBuffer message) { |
| Collection<BgpRouteEntry> addedRoutes = null; |
| Map<Ip4Prefix, BgpRouteEntry> deletedRoutes = new HashMap<>(); |
| |
| int minLength = |
| BgpConstants.BGP_UPDATE_MIN_LENGTH - BgpConstants.BGP_HEADER_LENGTH; |
| if (message.readableBytes() < minLength) { |
| log.debug("BGP RX UPDATE Error from {}: " + |
| "Message length {} too short. Must be at least {}", |
| bgpSession.getRemoteAddress(), 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; |
| } |
| |
| log.debug("BGP RX UPDATE message from {}", |
| bgpSession.getRemoteAddress()); |
| |
| // |
| // Parse the UPDATE message |
| // |
| |
| // |
| // Parse the Withdrawn Routes |
| // |
| int withdrawnRoutesLength = message.readUnsignedShort(); |
| if (withdrawnRoutesLength > message.readableBytes()) { |
| // ERROR: Malformed Attribute List |
| actionsBgpUpdateMalformedAttributeList(bgpSession, ctx); |
| return; |
| } |
| Collection<Ip4Prefix> withdrawnPrefixes = null; |
| try { |
| withdrawnPrefixes = parsePackedPrefixes(withdrawnRoutesLength, |
| message); |
| } catch (BgpParseException e) { |
| // ERROR: Invalid Network Field |
| log.debug("Exception parsing Withdrawn Prefixes from BGP peer {}: ", |
| bgpSession.getRemoteBgpId(), e); |
| actionsBgpUpdateInvalidNetworkField(bgpSession, ctx); |
| return; |
| } |
| for (Ip4Prefix prefix : withdrawnPrefixes) { |
| log.debug("BGP RX UPDATE message WITHDRAWN from {}: {}", |
| bgpSession.getRemoteAddress(), prefix); |
| BgpRouteEntry bgpRouteEntry = bgpSession.bgpRibIn().get(prefix); |
| if (bgpRouteEntry != null) { |
| deletedRoutes.put(prefix, bgpRouteEntry); |
| } |
| } |
| |
| // |
| // Parse the Path Attributes |
| // |
| try { |
| addedRoutes = parsePathAttributes(bgpSession, ctx, message); |
| } catch (BgpParseException e) { |
| log.debug("Exception parsing Path Attributes from BGP peer {}: ", |
| bgpSession.getRemoteBgpId(), e); |
| // NOTE: The session was already closed, so nothing else to do |
| return; |
| } |
| // Ignore WITHDRAWN routes that are ADDED |
| for (BgpRouteEntry bgpRouteEntry : addedRoutes) { |
| deletedRoutes.remove(bgpRouteEntry.prefix()); |
| } |
| |
| // Update the BGP RIB-IN |
| for (BgpRouteEntry bgpRouteEntry : deletedRoutes.values()) { |
| bgpSession.bgpRibIn().remove(bgpRouteEntry.prefix()); |
| } |
| for (BgpRouteEntry bgpRouteEntry : addedRoutes) { |
| bgpSession.bgpRibIn().put(bgpRouteEntry.prefix(), bgpRouteEntry); |
| } |
| |
| // Push the updates to the BGP Merged RIB |
| BgpSessionManager.BgpRouteSelector bgpRouteSelector = |
| bgpSession.getBgpSessionManager().getBgpRouteSelector(); |
| bgpRouteSelector.routeUpdates(bgpSession, addedRoutes, |
| deletedRoutes.values()); |
| |
| // Start the Session Timeout timer |
| bgpSession.restartSessionTimeoutTimer(ctx); |
| } |
| |
| /** |
| * Parse BGP Path Attributes from the BGP UPDATE message. |
| * |
| * @param bgpSession the BGP Session to use |
| * @param ctx the Channel Handler Context |
| * @param message the message to parse |
| * @return a collection of the result BGP Route Entries |
| * @throws BgpParseException |
| */ |
| private static Collection<BgpRouteEntry> parsePathAttributes( |
| BgpSession bgpSession, |
| ChannelHandlerContext ctx, |
| ChannelBuffer message) |
| throws BgpParseException { |
| Map<Ip4Prefix, BgpRouteEntry> addedRoutes = new HashMap<>(); |
| |
| // |
| // Parsed values |
| // |
| Short origin = -1; // Mandatory |
| BgpRouteEntry.AsPath asPath = null; // Mandatory |
| Ip4Address nextHop = null; // Mandatory |
| long multiExitDisc = // Optional |
| BgpConstants.Update.MultiExitDisc.LOWEST_MULTI_EXIT_DISC; |
| Long localPref = null; // Mandatory |
| Long aggregatorAsNumber = null; // Optional: unused |
| Ip4Address aggregatorIpAddress = null; // Optional: unused |
| |
| // |
| // Get and verify the Path Attributes Length |
| // |
| int pathAttributeLength = message.readUnsignedShort(); |
| if (pathAttributeLength > message.readableBytes()) { |
| // ERROR: Malformed Attribute List |
| actionsBgpUpdateMalformedAttributeList(bgpSession, ctx); |
| String errorMsg = "Malformed Attribute List"; |
| throw new BgpParseException(errorMsg); |
| } |
| if (pathAttributeLength == 0) { |
| return addedRoutes.values(); |
| } |
| |
| // |
| // Parse the Path Attributes |
| // |
| int pathAttributeEnd = message.readerIndex() + pathAttributeLength; |
| while (message.readerIndex() < pathAttributeEnd) { |
| int attrFlags = message.readUnsignedByte(); |
| if (message.readerIndex() >= pathAttributeEnd) { |
| // ERROR: Malformed Attribute List |
| actionsBgpUpdateMalformedAttributeList(bgpSession, ctx); |
| String errorMsg = "Malformed Attribute List"; |
| throw new BgpParseException(errorMsg); |
| } |
| int attrTypeCode = message.readUnsignedByte(); |
| |
| // The Attribute Flags |
| boolean optionalBit = ((0x80 & attrFlags) != 0); |
| boolean transitiveBit = ((0x40 & attrFlags) != 0); |
| boolean partialBit = ((0x20 & attrFlags) != 0); |
| boolean extendedLengthBit = ((0x10 & attrFlags) != 0); |
| |
| // The Attribute Length |
| int attrLen = 0; |
| int attrLenOctets = 1; |
| if (extendedLengthBit) { |
| attrLenOctets = 2; |
| } |
| if (message.readerIndex() + attrLenOctets > pathAttributeEnd) { |
| // ERROR: Malformed Attribute List |
| actionsBgpUpdateMalformedAttributeList(bgpSession, ctx); |
| String errorMsg = "Malformed Attribute List"; |
| throw new BgpParseException(errorMsg); |
| } |
| if (extendedLengthBit) { |
| attrLen = message.readUnsignedShort(); |
| } else { |
| attrLen = message.readUnsignedByte(); |
| } |
| if (message.readerIndex() + attrLen > pathAttributeEnd) { |
| // ERROR: Malformed Attribute List |
| actionsBgpUpdateMalformedAttributeList(bgpSession, ctx); |
| String errorMsg = "Malformed Attribute List"; |
| throw new BgpParseException(errorMsg); |
| } |
| |
| // Verify the Attribute Flags |
| verifyBgpUpdateAttributeFlags(bgpSession, ctx, attrTypeCode, |
| attrLen, attrFlags, message); |
| |
| // |
| // Extract the Attribute Value based on the Attribute Type Code |
| // |
| switch (attrTypeCode) { |
| |
| case BgpConstants.Update.Origin.TYPE: |
| // Attribute Type Code ORIGIN |
| origin = parseAttributeTypeOrigin(bgpSession, ctx, |
| attrTypeCode, attrLen, |
| attrFlags, message); |
| break; |
| |
| case BgpConstants.Update.AsPath.TYPE: |
| // Attribute Type Code AS_PATH |
| asPath = parseAttributeTypeAsPath(bgpSession, ctx, |
| attrTypeCode, attrLen, |
| attrFlags, message); |
| break; |
| |
| case BgpConstants.Update.NextHop.TYPE: |
| // Attribute Type Code NEXT_HOP |
| nextHop = parseAttributeTypeNextHop(bgpSession, ctx, |
| attrTypeCode, attrLen, |
| attrFlags, message); |
| break; |
| |
| case BgpConstants.Update.MultiExitDisc.TYPE: |
| // Attribute Type Code MULTI_EXIT_DISC |
| multiExitDisc = |
| parseAttributeTypeMultiExitDisc(bgpSession, ctx, |
| attrTypeCode, attrLen, |
| attrFlags, message); |
| break; |
| |
| case BgpConstants.Update.LocalPref.TYPE: |
| // Attribute Type Code LOCAL_PREF |
| localPref = |
| parseAttributeTypeLocalPref(bgpSession, ctx, |
| attrTypeCode, attrLen, |
| attrFlags, message); |
| break; |
| |
| case BgpConstants.Update.AtomicAggregate.TYPE: |
| // Attribute Type Code ATOMIC_AGGREGATE |
| parseAttributeTypeAtomicAggregate(bgpSession, ctx, |
| attrTypeCode, attrLen, |
| attrFlags, message); |
| // Nothing to do: this attribute is primarily informational |
| break; |
| |
| case BgpConstants.Update.Aggregator.TYPE: |
| // Attribute Type Code AGGREGATOR |
| Pair<Long, Ip4Address> aggregator = |
| parseAttributeTypeAggregator(bgpSession, ctx, |
| attrTypeCode, attrLen, |
| attrFlags, message); |
| aggregatorAsNumber = aggregator.getLeft(); |
| aggregatorIpAddress = aggregator.getRight(); |
| break; |
| |
| default: |
| // NOTE: Parse any new Attribute Types if needed |
| if (!optionalBit) { |
| // ERROR: Unrecognized Well-known Attribute |
| actionsBgpUpdateUnrecognizedWellKnownAttribute( |
| bgpSession, ctx, attrTypeCode, attrLen, attrFlags, |
| message); |
| String errorMsg = "Unrecognized Well-known Attribute: " + |
| attrTypeCode; |
| throw new BgpParseException(errorMsg); |
| } |
| |
| // Skip the data from the unrecognized attribute |
| log.debug("BGP RX UPDATE message from {}: " + |
| "Unrecognized Attribute Type {}", |
| bgpSession.getRemoteAddress(), attrTypeCode); |
| message.skipBytes(attrLen); |
| break; |
| } |
| } |
| |
| // Verify the Well-known Attributes |
| verifyBgpUpdateWellKnownAttributes(bgpSession, ctx, origin, asPath, |
| nextHop, localPref); |
| |
| // |
| // Parse the NLRI (Network Layer Reachability Information) |
| // |
| Collection<Ip4Prefix> addedPrefixes = null; |
| int nlriLength = message.readableBytes(); |
| try { |
| addedPrefixes = parsePackedPrefixes(nlriLength, message); |
| } catch (BgpParseException e) { |
| // ERROR: Invalid Network Field |
| log.debug("Exception parsing NLRI from BGP peer {}: ", |
| bgpSession.getRemoteBgpId(), e); |
| actionsBgpUpdateInvalidNetworkField(bgpSession, ctx); |
| // Rethrow the exception |
| throw e; |
| } |
| |
| // Generate the added routes |
| for (Ip4Prefix prefix : addedPrefixes) { |
| BgpRouteEntry bgpRouteEntry = |
| new BgpRouteEntry(bgpSession, prefix, nextHop, |
| origin.byteValue(), asPath, localPref); |
| bgpRouteEntry.setMultiExitDisc(multiExitDisc); |
| if (bgpRouteEntry.hasAsPathLoop(bgpSession.getLocalAs())) { |
| log.debug("BGP RX UPDATE message IGNORED from {}: {} " + |
| "nextHop {}: contains AS Path loop", |
| bgpSession.getRemoteAddress(), prefix, nextHop); |
| continue; |
| } else { |
| log.debug("BGP RX UPDATE message ADDED from {}: {} nextHop {}", |
| bgpSession.getRemoteAddress(), prefix, nextHop); |
| } |
| addedRoutes.put(prefix, bgpRouteEntry); |
| } |
| |
| return addedRoutes.values(); |
| } |
| |
| /** |
| * Verifies BGP UPDATE Well-known Attributes. |
| * |
| * @param bgpSession the BGP Session to use |
| * @param ctx the Channel Handler Context |
| * @param origin the ORIGIN well-known mandatory attribute |
| * @param asPath the AS_PATH well-known mandatory attribute |
| * @param nextHop the NEXT_HOP well-known mandatory attribute |
| * @param localPref the LOCAL_PREF required attribute |
| * @throws BgpParseException |
| */ |
| private static void verifyBgpUpdateWellKnownAttributes( |
| BgpSession bgpSession, |
| ChannelHandlerContext ctx, |
| Short origin, |
| BgpRouteEntry.AsPath asPath, |
| Ip4Address nextHop, |
| Long localPref) |
| throws BgpParseException { |
| // |
| // Check for Missing Well-known Attributes |
| // |
| if ((origin == null) || (origin == -1)) { |
| // Missing Attribute Type Code ORIGIN |
| int type = BgpConstants.Update.Origin.TYPE; |
| actionsBgpUpdateMissingWellKnownAttribute(bgpSession, ctx, type); |
| String errorMsg = "Missing Well-known Attribute: ORIGIN"; |
| throw new BgpParseException(errorMsg); |
| } |
| if (asPath == null) { |
| // Missing Attribute Type Code AS_PATH |
| int type = BgpConstants.Update.AsPath.TYPE; |
| actionsBgpUpdateMissingWellKnownAttribute(bgpSession, ctx, type); |
| String errorMsg = "Missing Well-known Attribute: AS_PATH"; |
| throw new BgpParseException(errorMsg); |
| } |
| if (nextHop == null) { |
| // Missing Attribute Type Code NEXT_HOP |
| int type = BgpConstants.Update.NextHop.TYPE; |
| actionsBgpUpdateMissingWellKnownAttribute(bgpSession, ctx, type); |
| String errorMsg = "Missing Well-known Attribute: NEXT_HOP"; |
| throw new BgpParseException(errorMsg); |
| } |
| if (localPref == null) { |
| // Missing Attribute Type Code LOCAL_PREF |
| // NOTE: Required for iBGP |
| int type = BgpConstants.Update.LocalPref.TYPE; |
| actionsBgpUpdateMissingWellKnownAttribute(bgpSession, ctx, type); |
| String errorMsg = "Missing Well-known Attribute: LOCAL_PREF"; |
| throw new BgpParseException(errorMsg); |
| } |
| } |
| |
| /** |
| * Verifies the BGP UPDATE Attribute Flags. |
| * |
| * @param bgpSession the BGP Session to use |
| * @param ctx the Channel Handler Context |
| * @param attrTypeCode the attribute type code |
| * @param attrLen the attribute length (in octets) |
| * @param attrFlags the attribute flags |
| * @param message the message to parse |
| * @throws BgpParseException |
| */ |
| private static void verifyBgpUpdateAttributeFlags( |
| BgpSession bgpSession, |
| ChannelHandlerContext ctx, |
| int attrTypeCode, |
| int attrLen, |
| int attrFlags, |
| ChannelBuffer message) |
| throws BgpParseException { |
| |
| // |
| // Assign the Attribute Type Name and the Well-known flag |
| // |
| String typeName = "UNKNOWN"; |
| boolean isWellKnown = false; |
| switch (attrTypeCode) { |
| case BgpConstants.Update.Origin.TYPE: |
| isWellKnown = true; |
| typeName = "ORIGIN"; |
| break; |
| case BgpConstants.Update.AsPath.TYPE: |
| isWellKnown = true; |
| typeName = "AS_PATH"; |
| break; |
| case BgpConstants.Update.NextHop.TYPE: |
| isWellKnown = true; |
| typeName = "NEXT_HOP"; |
| break; |
| case BgpConstants.Update.MultiExitDisc.TYPE: |
| isWellKnown = false; |
| typeName = "MULTI_EXIT_DISC"; |
| break; |
| case BgpConstants.Update.LocalPref.TYPE: |
| isWellKnown = true; |
| typeName = "LOCAL_PREF"; |
| break; |
| case BgpConstants.Update.AtomicAggregate.TYPE: |
| isWellKnown = true; |
| typeName = "ATOMIC_AGGREGATE"; |
| break; |
| case BgpConstants.Update.Aggregator.TYPE: |
| isWellKnown = false; |
| typeName = "AGGREGATOR"; |
| break; |
| default: |
| isWellKnown = false; |
| typeName = "UNKNOWN(" + attrTypeCode + ")"; |
| break; |
| } |
| |
| // |
| // Verify the Attribute Flags |
| // |
| boolean optionalBit = ((0x80 & attrFlags) != 0); |
| boolean transitiveBit = ((0x40 & attrFlags) != 0); |
| boolean partialBit = ((0x20 & attrFlags) != 0); |
| if ((isWellKnown && optionalBit) || |
| (isWellKnown && (!transitiveBit)) || |
| (isWellKnown && partialBit) || |
| (optionalBit && (!transitiveBit) && partialBit)) { |
| // |
| // ERROR: The Optional bit cannot be set for Well-known attributes |
| // ERROR: The Transtive bit MUST be 1 for well-known attributes |
| // ERROR: The Partial bit MUST be 0 for well-known attributes |
| // ERROR: The Partial bit MUST be 0 for optional non-transitive |
| // attributes |
| // |
| actionsBgpUpdateAttributeFlagsError( |
| bgpSession, ctx, attrTypeCode, attrLen, attrFlags, message); |
| String errorMsg = "Attribute Flags Error for " + typeName + ": " + |
| attrFlags; |
| throw new BgpParseException(errorMsg); |
| } |
| } |
| |
| /** |
| * Parses BGP UPDATE Attribute Type ORIGIN. |
| * |
| * @param bgpSession the BGP Session to use |
| * @param ctx the Channel Handler Context |
| * @param attrTypeCode the attribute type code |
| * @param attrLen the attribute length (in octets) |
| * @param attrFlags the attribute flags |
| * @param message the message to parse |
| * @return the parsed ORIGIN value |
| * @throws BgpParseException |
| */ |
| private static short parseAttributeTypeOrigin( |
| BgpSession bgpSession, |
| ChannelHandlerContext ctx, |
| int attrTypeCode, |
| int attrLen, |
| int attrFlags, |
| ChannelBuffer message) |
| throws BgpParseException { |
| |
| // Check the Attribute Length |
| if (attrLen != BgpConstants.Update.Origin.LENGTH) { |
| // ERROR: Attribute Length Error |
| actionsBgpUpdateAttributeLengthError( |
| bgpSession, ctx, attrTypeCode, attrLen, attrFlags, message); |
| String errorMsg = "Attribute Length Error"; |
| throw new BgpParseException(errorMsg); |
| } |
| |
| message.markReaderIndex(); |
| short origin = message.readUnsignedByte(); |
| switch (origin) { |
| case BgpConstants.Update.Origin.IGP: |
| // FALLTHROUGH |
| case BgpConstants.Update.Origin.EGP: |
| // FALLTHROUGH |
| case BgpConstants.Update.Origin.INCOMPLETE: |
| break; |
| default: |
| // ERROR: Invalid ORIGIN Attribute |
| message.resetReaderIndex(); |
| actionsBgpUpdateInvalidOriginAttribute( |
| bgpSession, ctx, attrTypeCode, attrLen, attrFlags, message, |
| origin); |
| String errorMsg = "Invalid ORIGIN Attribute: " + origin; |
| throw new BgpParseException(errorMsg); |
| } |
| |
| return origin; |
| } |
| |
| /** |
| * Parses BGP UPDATE Attribute AS Path. |
| * |
| * @param bgpSession the BGP Session to use |
| * @param ctx the Channel Handler Context |
| * @param attrTypeCode the attribute type code |
| * @param attrLen the attribute length (in octets) |
| * @param attrFlags the attribute flags |
| * @param message the message to parse |
| * @return the parsed AS Path |
| * @throws BgpParseException |
| */ |
| private static BgpRouteEntry.AsPath parseAttributeTypeAsPath( |
| BgpSession bgpSession, |
| ChannelHandlerContext ctx, |
| int attrTypeCode, |
| int attrLen, |
| int attrFlags, |
| ChannelBuffer message) |
| throws BgpParseException { |
| ArrayList<BgpRouteEntry.PathSegment> pathSegments = new ArrayList<>(); |
| |
| // |
| // Parse the message |
| // |
| while (attrLen > 0) { |
| if (attrLen < 2) { |
| // ERROR: Malformed AS_PATH |
| actionsBgpUpdateMalformedAsPath(bgpSession, ctx); |
| String errorMsg = "Malformed AS Path"; |
| throw new BgpParseException(errorMsg); |
| } |
| // Get the Path Segment Type and Length (in number of ASes) |
| short pathSegmentType = message.readUnsignedByte(); |
| short pathSegmentLength = message.readUnsignedByte(); |
| attrLen -= 2; |
| |
| // Verify the Path Segment Type |
| switch (pathSegmentType) { |
| case BgpConstants.Update.AsPath.AS_SET: |
| // FALLTHROUGH |
| case BgpConstants.Update.AsPath.AS_SEQUENCE: |
| // FALLTHROUGH |
| case BgpConstants.Update.AsPath.AS_CONFED_SEQUENCE: |
| // FALLTHROUGH |
| case BgpConstants.Update.AsPath.AS_CONFED_SET: |
| break; |
| default: |
| // ERROR: Invalid Path Segment Type |
| // |
| // NOTE: The BGP Spec (RFC 4271) doesn't contain Error Subcode |
| // for "Invalid Path Segment Type", hence we return |
| // the error as "Malformed AS_PATH". |
| // |
| actionsBgpUpdateMalformedAsPath(bgpSession, ctx); |
| String errorMsg = |
| "Invalid AS Path Segment Type: " + pathSegmentType; |
| throw new BgpParseException(errorMsg); |
| } |
| |
| // 4-octet AS number handling. |
| int asPathLen; |
| if (bgpSession.isAs4OctetCapable()) { |
| asPathLen = AsPath.AS_4OCTET_LENGTH; |
| } else { |
| asPathLen = AsPath.AS_LENGTH; |
| } |
| |
| // Parse the AS numbers |
| if (asPathLen * pathSegmentLength > attrLen) { |
| // ERROR: Malformed AS_PATH |
| actionsBgpUpdateMalformedAsPath(bgpSession, ctx); |
| String errorMsg = "Malformed AS Path"; |
| throw new BgpParseException(errorMsg); |
| } |
| attrLen -= (asPathLen * pathSegmentLength); |
| ArrayList<Long> segmentAsNumbers = new ArrayList<>(); |
| while (pathSegmentLength-- > 0) { |
| long asNumber; |
| if (asPathLen == AsPath.AS_4OCTET_LENGTH) { |
| asNumber = message.readUnsignedInt(); |
| } else { |
| asNumber = message.readUnsignedShort(); |
| } |
| segmentAsNumbers.add(asNumber); |
| } |
| |
| BgpRouteEntry.PathSegment pathSegment = |
| new BgpRouteEntry.PathSegment((byte) pathSegmentType, |
| segmentAsNumbers); |
| pathSegments.add(pathSegment); |
| } |
| |
| return new BgpRouteEntry.AsPath(pathSegments); |
| } |
| |
| /** |
| * Parses BGP UPDATE Attribute Type NEXT_HOP. |
| * |
| * @param bgpSession the BGP Session to use |
| * @param ctx the Channel Handler Context |
| * @param attrTypeCode the attribute type code |
| * @param attrLen the attribute length (in octets) |
| * @param attrFlags the attribute flags |
| * @param message the message to parse |
| * @return the parsed NEXT_HOP value |
| * @throws BgpParseException |
| */ |
| private static Ip4Address parseAttributeTypeNextHop( |
| BgpSession bgpSession, |
| ChannelHandlerContext ctx, |
| int attrTypeCode, |
| int attrLen, |
| int attrFlags, |
| ChannelBuffer message) |
| throws BgpParseException { |
| |
| // Check the Attribute Length |
| if (attrLen != BgpConstants.Update.NextHop.LENGTH) { |
| // ERROR: Attribute Length Error |
| actionsBgpUpdateAttributeLengthError( |
| bgpSession, ctx, attrTypeCode, attrLen, attrFlags, message); |
| String errorMsg = "Attribute Length Error"; |
| throw new BgpParseException(errorMsg); |
| } |
| |
| message.markReaderIndex(); |
| Ip4Address nextHopAddress = |
| Ip4Address.valueOf((int) message.readUnsignedInt()); |
| // |
| // Check whether the NEXT_HOP IP address is semantically correct. |
| // As per RFC 4271, Section 6.3: |
| // |
| // a) It MUST NOT be the IP address of the receiving speaker |
| // b) In the case of an EBGP .... |
| // |
| // Here we check only (a), because (b) doesn't apply for us: all our |
| // peers are iBGP. |
| // |
| if (nextHopAddress.equals(bgpSession.getLocalIp4Address())) { |
| // ERROR: Invalid NEXT_HOP Attribute |
| message.resetReaderIndex(); |
| actionsBgpUpdateInvalidNextHopAttribute( |
| bgpSession, ctx, attrTypeCode, attrLen, attrFlags, message, |
| nextHopAddress); |
| String errorMsg = "Invalid NEXT_HOP Attribute: " + nextHopAddress; |
| throw new BgpParseException(errorMsg); |
| } |
| |
| return nextHopAddress; |
| } |
| |
| /** |
| * Parses BGP UPDATE Attribute Type MULTI_EXIT_DISC. |
| * |
| * @param bgpSession the BGP Session to use |
| * @param ctx the Channel Handler Context |
| * @param attrTypeCode the attribute type code |
| * @param attrLen the attribute length (in octets) |
| * @param attrFlags the attribute flags |
| * @param message the message to parse |
| * @return the parsed MULTI_EXIT_DISC value |
| * @throws BgpParseException |
| */ |
| private static long parseAttributeTypeMultiExitDisc( |
| BgpSession bgpSession, |
| ChannelHandlerContext ctx, |
| int attrTypeCode, |
| int attrLen, |
| int attrFlags, |
| ChannelBuffer message) |
| throws BgpParseException { |
| |
| // Check the Attribute Length |
| if (attrLen != BgpConstants.Update.MultiExitDisc.LENGTH) { |
| // ERROR: Attribute Length Error |
| actionsBgpUpdateAttributeLengthError( |
| bgpSession, ctx, attrTypeCode, attrLen, attrFlags, message); |
| String errorMsg = "Attribute Length Error"; |
| throw new BgpParseException(errorMsg); |
| } |
| |
| long multiExitDisc = message.readUnsignedInt(); |
| return multiExitDisc; |
| } |
| |
| /** |
| * Parses BGP UPDATE Attribute Type LOCAL_PREF. |
| * |
| * @param bgpSession the BGP Session to use |
| * @param ctx the Channel Handler Context |
| * @param attrTypeCode the attribute type code |
| * @param attrLen the attribute length (in octets) |
| * @param attrFlags the attribute flags |
| * @param message the message to parse |
| * @return the parsed LOCAL_PREF value |
| * @throws BgpParseException |
| */ |
| private static long parseAttributeTypeLocalPref( |
| BgpSession bgpSession, |
| ChannelHandlerContext ctx, |
| int attrTypeCode, |
| int attrLen, |
| int attrFlags, |
| ChannelBuffer message) |
| throws BgpParseException { |
| |
| // Check the Attribute Length |
| if (attrLen != BgpConstants.Update.LocalPref.LENGTH) { |
| // ERROR: Attribute Length Error |
| actionsBgpUpdateAttributeLengthError( |
| bgpSession, ctx, attrTypeCode, attrLen, attrFlags, message); |
| String errorMsg = "Attribute Length Error"; |
| throw new BgpParseException(errorMsg); |
| } |
| |
| long localPref = message.readUnsignedInt(); |
| return localPref; |
| } |
| |
| /** |
| * Parses BGP UPDATE Attribute Type ATOMIC_AGGREGATE. |
| * |
| * @param bgpSession the BGP Session to use |
| * @param ctx the Channel Handler Context |
| * @param attrTypeCode the attribute type code |
| * @param attrLen the attribute length (in octets) |
| * @param attrFlags the attribute flags |
| * @param message the message to parse |
| * @throws BgpParseException |
| */ |
| private static void parseAttributeTypeAtomicAggregate( |
| BgpSession bgpSession, |
| ChannelHandlerContext ctx, |
| int attrTypeCode, |
| int attrLen, |
| int attrFlags, |
| ChannelBuffer message) |
| throws BgpParseException { |
| |
| // Check the Attribute Length |
| if (attrLen != BgpConstants.Update.AtomicAggregate.LENGTH) { |
| // ERROR: Attribute Length Error |
| actionsBgpUpdateAttributeLengthError( |
| bgpSession, ctx, attrTypeCode, attrLen, attrFlags, message); |
| String errorMsg = "Attribute Length Error"; |
| throw new BgpParseException(errorMsg); |
| } |
| |
| // Nothing to do: this attribute is primarily informational |
| } |
| |
| /** |
| * Parses BGP UPDATE Attribute Type AGGREGATOR. |
| * |
| * @param bgpSession the BGP Session to use |
| * @param ctx the Channel Handler Context |
| * @param attrTypeCode the attribute type code |
| * @param attrLen the attribute length (in octets) |
| * @param attrFlags the attribute flags |
| * @param message the message to parse |
| * @return the parsed AGGREGATOR value: a tuple of <AS-Number, IP-Address> |
| * @throws BgpParseException |
| */ |
| private static Pair<Long, Ip4Address> parseAttributeTypeAggregator( |
| BgpSession bgpSession, |
| ChannelHandlerContext ctx, |
| int attrTypeCode, |
| int attrLen, |
| int attrFlags, |
| ChannelBuffer message) |
| throws BgpParseException { |
| |
| // Check the Attribute Length |
| if (attrLen != BgpConstants.Update.Aggregator.LENGTH) { |
| // ERROR: Attribute Length Error |
| actionsBgpUpdateAttributeLengthError( |
| bgpSession, ctx, attrTypeCode, attrLen, attrFlags, message); |
| String errorMsg = "Attribute Length Error"; |
| throw new BgpParseException(errorMsg); |
| } |
| |
| // The AGGREGATOR AS number |
| long aggregatorAsNumber = message.readUnsignedShort(); |
| // The AGGREGATOR IP address |
| Ip4Address aggregatorIpAddress = |
| Ip4Address.valueOf((int) message.readUnsignedInt()); |
| |
| Pair<Long, Ip4Address> aggregator = Pair.of(aggregatorAsNumber, |
| aggregatorIpAddress); |
| return aggregator; |
| } |
| |
| /** |
| * Parses a message that contains encoded IPv4 network prefixes. |
| * <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 totalLength the total length of the data to parse |
| * @param message the message with data to parse |
| * @return a collection of parsed IPv4 network prefixes |
| * @throws BgpParseException |
| */ |
| private static Collection<Ip4Prefix> parsePackedPrefixes( |
| int totalLength, |
| ChannelBuffer message) |
| throws BgpParseException { |
| Collection<Ip4Prefix> result = new ArrayList<>(); |
| |
| if (totalLength == 0) { |
| return result; |
| } |
| |
| // Parse the data |
| int dataEnd = message.readerIndex() + totalLength; |
| while (message.readerIndex() < dataEnd) { |
| int prefixBitlen = message.readUnsignedByte(); |
| int prefixBytelen = (prefixBitlen + 7) / 8; // Round-up |
| if (message.readerIndex() + prefixBytelen > dataEnd) { |
| String errorMsg = "Malformed Network Prefixes"; |
| throw new BgpParseException(errorMsg); |
| } |
| |
| long address = 0; |
| long extraShift = (4 - prefixBytelen) * 8; |
| while (prefixBytelen > 0) { |
| address <<= 8; |
| address |= message.readUnsignedByte(); |
| prefixBytelen--; |
| } |
| address <<= extraShift; |
| Ip4Prefix prefix = |
| Ip4Prefix.valueOf(Ip4Address.valueOf((int) address), |
| prefixBitlen); |
| result.add(prefix); |
| } |
| |
| return result; |
| } |
| |
| /** |
| * Applies the appropriate actions after detecting BGP UPDATE |
| * Invalid Network Field Error: send NOTIFICATION and close the channel. |
| * |
| * @param bgpSession the BGP Session to use |
| * @param ctx the Channel Handler Context |
| */ |
| private static void actionsBgpUpdateInvalidNetworkField( |
| BgpSession bgpSession, |
| ChannelHandlerContext ctx) { |
| log.debug("BGP RX UPDATE Error from {}: Invalid Network Field", |
| bgpSession.getRemoteAddress()); |
| |
| // |
| // ERROR: Invalid Network Field |
| // |
| // Send NOTIFICATION and close the connection |
| int errorCode = UpdateMessageError.ERROR_CODE; |
| int errorSubcode = UpdateMessageError.INVALID_NETWORK_FIELD; |
| ChannelBuffer txMessage = |
| BgpNotification.prepareBgpNotification(errorCode, errorSubcode, |
| null); |
| ctx.getChannel().write(txMessage); |
| bgpSession.closeSession(ctx); |
| } |
| |
| /** |
| * Applies the appropriate actions after detecting BGP UPDATE |
| * Malformed Attribute List Error: send NOTIFICATION and close the channel. |
| * |
| * @param bgpSession the BGP Session to use |
| * @param ctx the Channel Handler Context |
| */ |
| private static void actionsBgpUpdateMalformedAttributeList( |
| BgpSession bgpSession, |
| ChannelHandlerContext ctx) { |
| log.debug("BGP RX UPDATE Error from {}: Malformed Attribute List", |
| bgpSession.getRemoteAddress()); |
| |
| // |
| // ERROR: Malformed Attribute List |
| // |
| // Send NOTIFICATION and close the connection |
| int errorCode = UpdateMessageError.ERROR_CODE; |
| int errorSubcode = UpdateMessageError.MALFORMED_ATTRIBUTE_LIST; |
| ChannelBuffer txMessage = |
| BgpNotification.prepareBgpNotification(errorCode, errorSubcode, |
| null); |
| ctx.getChannel().write(txMessage); |
| bgpSession.closeSession(ctx); |
| } |
| |
| /** |
| * Applies the appropriate actions after detecting BGP UPDATE |
| * Missing Well-known Attribute Error: send NOTIFICATION and close the |
| * channel. |
| * |
| * @param bgpSession the BGP Session to use |
| * @param ctx the Channel Handler Context |
| * @param missingAttrTypeCode the missing attribute type code |
| */ |
| private static void actionsBgpUpdateMissingWellKnownAttribute( |
| BgpSession bgpSession, |
| ChannelHandlerContext ctx, |
| int missingAttrTypeCode) { |
| log.debug("BGP RX UPDATE Error from {}: Missing Well-known Attribute: {}", |
| bgpSession.getRemoteAddress(), missingAttrTypeCode); |
| |
| // |
| // ERROR: Missing Well-known Attribute |
| // |
| // Send NOTIFICATION and close the connection |
| int errorCode = UpdateMessageError.ERROR_CODE; |
| int errorSubcode = UpdateMessageError.MISSING_WELL_KNOWN_ATTRIBUTE; |
| ChannelBuffer data = ChannelBuffers.buffer(1); |
| data.writeByte(missingAttrTypeCode); |
| ChannelBuffer txMessage = |
| BgpNotification.prepareBgpNotification(errorCode, errorSubcode, |
| data); |
| ctx.getChannel().write(txMessage); |
| bgpSession.closeSession(ctx); |
| } |
| |
| /** |
| * Applies the appropriate actions after detecting BGP UPDATE |
| * Invalid ORIGIN Attribute Error: send NOTIFICATION and close the channel. |
| * |
| * @param bgpSession the BGP Session to use |
| * @param ctx the Channel Handler Context |
| * @param attrTypeCode the attribute type code |
| * @param attrLen the attribute length (in octets) |
| * @param attrFlags the attribute flags |
| * @param message the message with the data |
| * @param origin the ORIGIN attribute value |
| */ |
| private static void actionsBgpUpdateInvalidOriginAttribute( |
| BgpSession bgpSession, |
| ChannelHandlerContext ctx, |
| int attrTypeCode, |
| int attrLen, |
| int attrFlags, |
| ChannelBuffer message, |
| short origin) { |
| log.debug("BGP RX UPDATE Error from {}: Invalid ORIGIN Attribute", |
| bgpSession.getRemoteAddress()); |
| |
| // |
| // ERROR: Invalid ORIGIN Attribute |
| // |
| // Send NOTIFICATION and close the connection |
| int errorCode = UpdateMessageError.ERROR_CODE; |
| int errorSubcode = UpdateMessageError.INVALID_ORIGIN_ATTRIBUTE; |
| ChannelBuffer data = |
| prepareBgpUpdateNotificationDataPayload(attrTypeCode, attrLen, |
| attrFlags, message); |
| ChannelBuffer txMessage = |
| BgpNotification.prepareBgpNotification(errorCode, errorSubcode, |
| data); |
| ctx.getChannel().write(txMessage); |
| bgpSession.closeSession(ctx); |
| } |
| |
| /** |
| * Applies the appropriate actions after detecting BGP UPDATE |
| * Attribute Flags Error: send NOTIFICATION and close the channel. |
| * |
| * @param bgpSession the BGP Session to use |
| * @param ctx the Channel Handler Context |
| * @param attrTypeCode the attribute type code |
| * @param attrLen the attribute length (in octets) |
| * @param attrFlags the attribute flags |
| * @param message the message with the data |
| */ |
| private static void actionsBgpUpdateAttributeFlagsError( |
| BgpSession bgpSession, |
| ChannelHandlerContext ctx, |
| int attrTypeCode, |
| int attrLen, |
| int attrFlags, |
| ChannelBuffer message) { |
| log.debug("BGP RX UPDATE Error from {}: Attribute Flags Error", |
| bgpSession.getRemoteAddress()); |
| |
| // |
| // ERROR: Attribute Flags Error |
| // |
| // Send NOTIFICATION and close the connection |
| int errorCode = UpdateMessageError.ERROR_CODE; |
| int errorSubcode = UpdateMessageError.ATTRIBUTE_FLAGS_ERROR; |
| ChannelBuffer data = |
| prepareBgpUpdateNotificationDataPayload(attrTypeCode, attrLen, |
| attrFlags, message); |
| ChannelBuffer txMessage = |
| BgpNotification.prepareBgpNotification(errorCode, errorSubcode, |
| data); |
| ctx.getChannel().write(txMessage); |
| bgpSession.closeSession(ctx); |
| } |
| |
| /** |
| * Applies the appropriate actions after detecting BGP UPDATE |
| * Invalid NEXT_HOP Attribute Error: send NOTIFICATION and close the |
| * channel. |
| * |
| * @param bgpSession the BGP Session to use |
| * @param ctx the Channel Handler Context |
| * @param attrTypeCode the attribute type code |
| * @param attrLen the attribute length (in octets) |
| * @param attrFlags the attribute flags |
| * @param message the message with the data |
| * @param nextHop the NEXT_HOP attribute value |
| */ |
| private static void actionsBgpUpdateInvalidNextHopAttribute( |
| BgpSession bgpSession, |
| ChannelHandlerContext ctx, |
| int attrTypeCode, |
| int attrLen, |
| int attrFlags, |
| ChannelBuffer message, |
| Ip4Address nextHop) { |
| log.debug("BGP RX UPDATE Error from {}: Invalid NEXT_HOP Attribute {}", |
| bgpSession.getRemoteAddress(), nextHop); |
| |
| // |
| // ERROR: Invalid ORIGIN Attribute |
| // |
| // Send NOTIFICATION and close the connection |
| int errorCode = UpdateMessageError.ERROR_CODE; |
| int errorSubcode = UpdateMessageError.INVALID_NEXT_HOP_ATTRIBUTE; |
| ChannelBuffer data = |
| prepareBgpUpdateNotificationDataPayload(attrTypeCode, attrLen, |
| attrFlags, message); |
| ChannelBuffer txMessage = |
| BgpNotification.prepareBgpNotification(errorCode, errorSubcode, |
| data); |
| ctx.getChannel().write(txMessage); |
| bgpSession.closeSession(ctx); |
| } |
| |
| /** |
| * Applies the appropriate actions after detecting BGP UPDATE |
| * Unrecognized Well-known Attribute Error: send NOTIFICATION and close |
| * the channel. |
| * |
| * @param bgpSession the BGP Session to use |
| * @param ctx the Channel Handler Context |
| * @param attrTypeCode the attribute type code |
| * @param attrLen the attribute length (in octets) |
| * @param attrFlags the attribute flags |
| * @param message the message with the data |
| */ |
| private static void actionsBgpUpdateUnrecognizedWellKnownAttribute( |
| BgpSession bgpSession, |
| ChannelHandlerContext ctx, |
| int attrTypeCode, |
| int attrLen, |
| int attrFlags, |
| ChannelBuffer message) { |
| log.debug("BGP RX UPDATE Error from {}: " + |
| "Unrecognized Well-known Attribute Error: {}", |
| bgpSession.getRemoteAddress(), attrTypeCode); |
| |
| // |
| // ERROR: Unrecognized Well-known Attribute |
| // |
| // Send NOTIFICATION and close the connection |
| int errorCode = UpdateMessageError.ERROR_CODE; |
| int errorSubcode = |
| UpdateMessageError.UNRECOGNIZED_WELL_KNOWN_ATTRIBUTE; |
| ChannelBuffer data = |
| prepareBgpUpdateNotificationDataPayload(attrTypeCode, attrLen, |
| attrFlags, message); |
| ChannelBuffer txMessage = |
| BgpNotification.prepareBgpNotification(errorCode, errorSubcode, |
| data); |
| ctx.getChannel().write(txMessage); |
| bgpSession.closeSession(ctx); |
| } |
| |
| /** |
| * Applies the appropriate actions after detecting BGP UPDATE |
| * Attribute Length Error: send NOTIFICATION and close the channel. |
| * |
| * @param bgpSession the BGP Session to use |
| * @param ctx the Channel Handler Context |
| * @param attrTypeCode the attribute type code |
| * @param attrLen the attribute length (in octets) |
| * @param attrFlags the attribute flags |
| * @param message the message with the data |
| */ |
| private static void actionsBgpUpdateAttributeLengthError( |
| BgpSession bgpSession, |
| ChannelHandlerContext ctx, |
| int attrTypeCode, |
| int attrLen, |
| int attrFlags, |
| ChannelBuffer message) { |
| log.debug("BGP RX UPDATE Error from {}: Attribute Length Error", |
| bgpSession.getRemoteAddress()); |
| |
| // |
| // ERROR: Attribute Length Error |
| // |
| // Send NOTIFICATION and close the connection |
| int errorCode = UpdateMessageError.ERROR_CODE; |
| int errorSubcode = UpdateMessageError.ATTRIBUTE_LENGTH_ERROR; |
| ChannelBuffer data = |
| prepareBgpUpdateNotificationDataPayload(attrTypeCode, attrLen, |
| attrFlags, message); |
| ChannelBuffer txMessage = |
| BgpNotification.prepareBgpNotification(errorCode, errorSubcode, |
| data); |
| ctx.getChannel().write(txMessage); |
| bgpSession.closeSession(ctx); |
| } |
| |
| /** |
| * Applies the appropriate actions after detecting BGP UPDATE |
| * Malformed AS_PATH Error: send NOTIFICATION and close the channel. |
| * |
| * @param bgpSession the BGP Session to use |
| * @param ctx the Channel Handler Context |
| */ |
| private static void actionsBgpUpdateMalformedAsPath( |
| BgpSession bgpSession, |
| ChannelHandlerContext ctx) { |
| log.debug("BGP RX UPDATE Error from {}: Malformed AS Path", |
| bgpSession.getRemoteAddress()); |
| |
| // |
| // ERROR: Malformed AS_PATH |
| // |
| // Send NOTIFICATION and close the connection |
| int errorCode = UpdateMessageError.ERROR_CODE; |
| int errorSubcode = UpdateMessageError.MALFORMED_AS_PATH; |
| ChannelBuffer txMessage = |
| BgpNotification.prepareBgpNotification(errorCode, errorSubcode, |
| null); |
| ctx.getChannel().write(txMessage); |
| bgpSession.closeSession(ctx); |
| } |
| |
| /** |
| * Prepares BGP UPDATE Notification data payload. |
| * |
| * @param attrTypeCode the attribute type code |
| * @param attrLen the attribute length (in octets) |
| * @param attrFlags the attribute flags |
| * @param message the message with the data |
| * @return the buffer with the data payload for the BGP UPDATE Notification |
| */ |
| private static ChannelBuffer prepareBgpUpdateNotificationDataPayload( |
| int attrTypeCode, |
| int attrLen, |
| int attrFlags, |
| ChannelBuffer message) { |
| // Compute the attribute length field octets |
| boolean extendedLengthBit = ((0x10 & attrFlags) != 0); |
| int attrLenOctets = 1; |
| if (extendedLengthBit) { |
| attrLenOctets = 2; |
| } |
| ChannelBuffer data = |
| ChannelBuffers.buffer(attrLen + attrLenOctets + 1); |
| data.writeByte(attrTypeCode); |
| if (extendedLengthBit) { |
| data.writeShort(attrLen); |
| } else { |
| data.writeByte(attrLen); |
| } |
| data.writeBytes(message, attrLen); |
| return data; |
| } |
| } |