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; |
| 24 | import org.slf4j.Logger; |
| 25 | import org.slf4j.LoggerFactory; |
| 26 | |
| 27 | /** |
| 28 | * A class for handling BGP OPEN messages. |
| 29 | */ |
| 30 | final class BgpOpen { |
| 31 | private static final Logger log = LoggerFactory.getLogger(BgpOpen.class); |
| 32 | |
| 33 | /** |
| 34 | * Default constructor. |
| 35 | * <p> |
| 36 | * The constructor is private to prevent creating an instance of |
| 37 | * this utility class. |
| 38 | */ |
| 39 | private BgpOpen() { |
| 40 | } |
| 41 | |
| 42 | /** |
| 43 | * Processes BGP OPEN message. |
| 44 | * |
| 45 | * @param bgpSession the BGP Session to use |
| 46 | * @param ctx the Channel Handler Context |
| 47 | * @param message the message to process |
| 48 | */ |
| 49 | static void processBgpOpen(BgpSession bgpSession, |
| 50 | ChannelHandlerContext ctx, |
| 51 | ChannelBuffer message) { |
| 52 | int minLength = |
| 53 | BgpConstants.BGP_OPEN_MIN_LENGTH - BgpConstants.BGP_HEADER_LENGTH; |
| 54 | if (message.readableBytes() < minLength) { |
| 55 | log.debug("BGP RX OPEN Error from {}: " + |
| 56 | "Message length {} too short. Must be at least {}", |
| 57 | bgpSession.getRemoteAddress(), message.readableBytes(), |
| 58 | minLength); |
| 59 | // |
| 60 | // ERROR: Bad Message Length |
| 61 | // |
| 62 | // Send NOTIFICATION and close the connection |
| 63 | ChannelBuffer txMessage = |
| 64 | BgpNotification.prepareBgpNotificationBadMessageLength( |
| 65 | message.readableBytes() + BgpConstants.BGP_HEADER_LENGTH); |
| 66 | ctx.getChannel().write(txMessage); |
| 67 | bgpSession.closeSession(ctx); |
| 68 | return; |
| 69 | } |
| 70 | |
| 71 | // |
| 72 | // Parse the OPEN message |
| 73 | // |
| 74 | // Remote BGP version |
| 75 | int remoteBgpVersion = message.readUnsignedByte(); |
| 76 | if (remoteBgpVersion != BgpConstants.BGP_VERSION) { |
| 77 | log.debug("BGP RX OPEN Error from {}: " + |
| 78 | "Unsupported BGP version {}. Should be {}", |
| 79 | bgpSession.getRemoteAddress(), remoteBgpVersion, |
| 80 | BgpConstants.BGP_VERSION); |
| 81 | // |
| 82 | // ERROR: Unsupported Version Number |
| 83 | // |
| 84 | // Send NOTIFICATION and close the connection |
| 85 | int errorCode = OpenMessageError.ERROR_CODE; |
| 86 | int errorSubcode = OpenMessageError.UNSUPPORTED_VERSION_NUMBER; |
| 87 | ChannelBuffer data = ChannelBuffers.buffer(2); |
| 88 | data.writeShort(BgpConstants.BGP_VERSION); |
| 89 | ChannelBuffer txMessage = |
| 90 | BgpNotification.prepareBgpNotification(errorCode, errorSubcode, |
| 91 | data); |
| 92 | ctx.getChannel().write(txMessage); |
| 93 | bgpSession.closeSession(ctx); |
| 94 | return; |
| 95 | } |
| 96 | bgpSession.setRemoteBgpVersion(remoteBgpVersion); |
| 97 | |
| 98 | // Remote AS number |
| 99 | long remoteAs = message.readUnsignedShort(); |
| 100 | // |
| 101 | // Verify that the AS number is same for all other BGP Sessions |
| 102 | // NOTE: This check applies only for our use-case where all BGP |
| 103 | // sessions are iBGP. |
| 104 | // |
| 105 | for (BgpSession bs : bgpSession.getBgpSessionManager().getBgpSessions()) { |
| 106 | if ((bs.getRemoteAs() != 0) && (remoteAs != bs.getRemoteAs())) { |
| 107 | log.debug("BGP RX OPEN Error from {}: Bad Peer AS {}. " + |
| 108 | "Expected {}", |
| 109 | bgpSession.getRemoteAddress(), remoteAs, |
| 110 | bs.getRemoteAs()); |
| 111 | // |
| 112 | // ERROR: Bad Peer AS |
| 113 | // |
| 114 | // Send NOTIFICATION and close the connection |
| 115 | int errorCode = OpenMessageError.ERROR_CODE; |
| 116 | int errorSubcode = OpenMessageError.BAD_PEER_AS; |
| 117 | ChannelBuffer txMessage = |
| 118 | BgpNotification.prepareBgpNotification(errorCode, |
| 119 | errorSubcode, null); |
| 120 | ctx.getChannel().write(txMessage); |
| 121 | bgpSession.closeSession(ctx); |
| 122 | return; |
| 123 | } |
| 124 | } |
| 125 | bgpSession.setRemoteAs(remoteAs); |
| 126 | |
| 127 | // Remote Hold Time |
| 128 | long remoteHoldtime = message.readUnsignedShort(); |
| 129 | if ((remoteHoldtime != 0) && |
| 130 | (remoteHoldtime < BgpConstants.BGP_KEEPALIVE_MIN_HOLDTIME)) { |
| 131 | log.debug("BGP RX OPEN Error from {}: " + |
| 132 | "Unacceptable Hold Time field {}. " + |
| 133 | "Should be 0 or at least {}", |
| 134 | bgpSession.getRemoteAddress(), remoteHoldtime, |
| 135 | BgpConstants.BGP_KEEPALIVE_MIN_HOLDTIME); |
| 136 | // |
| 137 | // ERROR: Unacceptable Hold Time |
| 138 | // |
| 139 | // Send NOTIFICATION and close the connection |
| 140 | int errorCode = OpenMessageError.ERROR_CODE; |
| 141 | int errorSubcode = OpenMessageError.UNACCEPTABLE_HOLD_TIME; |
| 142 | ChannelBuffer txMessage = |
| 143 | BgpNotification.prepareBgpNotification(errorCode, errorSubcode, |
| 144 | null); |
| 145 | ctx.getChannel().write(txMessage); |
| 146 | bgpSession.closeSession(ctx); |
| 147 | return; |
| 148 | } |
| 149 | bgpSession.setRemoteHoldtime(remoteHoldtime); |
| 150 | |
| 151 | // Remote BGP Identifier |
| 152 | Ip4Address remoteBgpId = |
| 153 | Ip4Address.valueOf((int) message.readUnsignedInt()); |
| 154 | bgpSession.setRemoteBgpId(remoteBgpId); |
| 155 | |
| 156 | // Optional Parameters |
| 157 | int optParamLen = message.readUnsignedByte(); |
| 158 | if (message.readableBytes() < optParamLen) { |
| 159 | log.debug("BGP RX OPEN Error from {}: " + |
| 160 | "Invalid Optional Parameter Length field {}. " + |
| 161 | "Remaining Optional Parameters {}", |
| 162 | bgpSession.getRemoteAddress(), optParamLen, |
| 163 | message.readableBytes()); |
| 164 | // |
| 165 | // ERROR: Invalid Optional Parameter Length field: Unspecific |
| 166 | // |
| 167 | // Send NOTIFICATION and close the connection |
| 168 | int errorCode = OpenMessageError.ERROR_CODE; |
| 169 | int errorSubcode = Notifications.ERROR_SUBCODE_UNSPECIFIC; |
| 170 | ChannelBuffer txMessage = |
| 171 | BgpNotification.prepareBgpNotification(errorCode, errorSubcode, |
| 172 | null); |
| 173 | ctx.getChannel().write(txMessage); |
| 174 | bgpSession.closeSession(ctx); |
| 175 | return; |
| 176 | } |
| 177 | // NOTE: Parse the optional parameters (if needed) |
| 178 | message.readBytes(optParamLen); // NOTE: data ignored |
| 179 | |
| 180 | log.debug("BGP RX OPEN message from {}: " + |
| 181 | "BGPv{} AS {} BGP-ID {} Holdtime {}", |
| 182 | bgpSession.getRemoteAddress(), remoteBgpVersion, remoteAs, |
| 183 | remoteBgpId, remoteHoldtime); |
| 184 | |
| 185 | // Send my OPEN followed by KEEPALIVE |
| 186 | ChannelBuffer txMessage = prepareBgpOpen(bgpSession); |
| 187 | ctx.getChannel().write(txMessage); |
| 188 | // |
| 189 | txMessage = BgpKeepalive.prepareBgpKeepalive(); |
| 190 | ctx.getChannel().write(txMessage); |
| 191 | |
| 192 | // Start the KEEPALIVE timer |
| 193 | bgpSession.restartKeepaliveTimer(ctx); |
| 194 | |
| 195 | // Start the Session Timeout timer |
| 196 | bgpSession.restartSessionTimeoutTimer(ctx); |
| 197 | } |
| 198 | |
| 199 | /** |
| 200 | * Prepares BGP OPEN message. |
| 201 | * |
| 202 | * @param bgpSession the BGP Session to use |
| 203 | * @return the message to transmit (BGP header included) |
| 204 | */ |
| 205 | private static ChannelBuffer prepareBgpOpen(BgpSession bgpSession) { |
| 206 | ChannelBuffer message = |
| 207 | ChannelBuffers.buffer(BgpConstants.BGP_MESSAGE_MAX_LENGTH); |
| 208 | |
| 209 | // |
| 210 | // Prepare the OPEN message payload |
| 211 | // |
| 212 | message.writeByte(bgpSession.getLocalBgpVersion()); |
| 213 | message.writeShort((int) bgpSession.getLocalAs()); |
| 214 | message.writeShort((int) bgpSession.getLocalHoldtime()); |
| 215 | message.writeInt(bgpSession.getLocalBgpId().toInt()); |
| 216 | message.writeByte(0); // No Optional Parameters |
| 217 | return BgpMessage.prepareBgpMessage(BgpConstants.BGP_TYPE_OPEN, |
| 218 | message); |
| 219 | } |
| 220 | } |