Jonathan Hart | ab63aac | 2014-10-16 08:52:55 -0700 | [diff] [blame] | 1 | package org.onlab.onos.sdnip.bgp; |
| 2 | |
| 3 | import static com.google.common.base.Preconditions.checkNotNull; |
| 4 | |
| 5 | import java.util.ArrayList; |
| 6 | import java.util.Objects; |
| 7 | |
| 8 | import org.onlab.onos.sdnip.RouteEntry; |
| 9 | import org.onlab.packet.IpAddress; |
| 10 | import org.onlab.packet.IpPrefix; |
| 11 | |
| 12 | import com.google.common.base.MoreObjects; |
| 13 | |
| 14 | /** |
| 15 | * Represents a route in BGP. |
| 16 | */ |
| 17 | public class BgpRouteEntry extends RouteEntry { |
| 18 | private final BgpSession bgpSession; // The BGP Session the route was |
| 19 | // received on |
| 20 | private final byte origin; // Route ORIGIN: IGP, EGP, INCOMPLETE |
| 21 | private final AsPath asPath; // The AS Path |
| 22 | private final long localPref; // The local preference for the route |
| 23 | private long multiExitDisc = |
| 24 | BgpConstants.Update.MultiExitDisc.LOWEST_MULTI_EXIT_DISC; |
| 25 | |
| 26 | /** |
| 27 | * Class constructor. |
| 28 | * |
| 29 | * @param bgpSession the BGP Session the route was received on |
| 30 | * @param prefix the prefix of the route |
| 31 | * @param nextHop the next hop of the route |
| 32 | * @param origin the route origin: 0=IGP, 1=EGP, 2=INCOMPLETE |
| 33 | * @param asPath the AS path |
| 34 | * @param localPref the route local preference |
| 35 | */ |
| 36 | public BgpRouteEntry(BgpSession bgpSession, IpPrefix prefix, |
| 37 | IpAddress nextHop, byte origin, |
| 38 | BgpRouteEntry.AsPath asPath, long localPref) { |
| 39 | super(prefix, nextHop); |
| 40 | this.bgpSession = checkNotNull(bgpSession); |
| 41 | this.origin = origin; |
| 42 | this.asPath = checkNotNull(asPath); |
| 43 | this.localPref = localPref; |
| 44 | } |
| 45 | |
| 46 | /** |
| 47 | * Gets the BGP Session the route was received on. |
| 48 | * |
| 49 | * @return the BGP Session the route was received on |
| 50 | */ |
| 51 | public BgpSession getBgpSession() { |
| 52 | return bgpSession; |
| 53 | } |
| 54 | |
| 55 | /** |
| 56 | * Gets the route origin: 0=IGP, 1=EGP, 2=INCOMPLETE. |
| 57 | * |
| 58 | * @return the route origin: 0=IGP, 1=EGP, 2=INCOMPLETE |
| 59 | */ |
| 60 | public byte getOrigin() { |
| 61 | return origin; |
| 62 | } |
| 63 | |
| 64 | /** |
| 65 | * Gets the route AS path. |
| 66 | * |
| 67 | * @return the route AS path |
| 68 | */ |
| 69 | public BgpRouteEntry.AsPath getAsPath() { |
| 70 | return asPath; |
| 71 | } |
| 72 | |
| 73 | /** |
| 74 | * Gets the route local preference. |
| 75 | * |
| 76 | * @return the route local preference |
| 77 | */ |
| 78 | public long getLocalPref() { |
| 79 | return localPref; |
| 80 | } |
| 81 | |
| 82 | /** |
| 83 | * Gets the route MED (Multi-Exit Discriminator). |
| 84 | * |
| 85 | * @return the route MED (Multi-Exit Discriminator) |
| 86 | */ |
| 87 | public long getMultiExitDisc() { |
| 88 | return multiExitDisc; |
| 89 | } |
| 90 | |
| 91 | /** |
| 92 | * Sets the route MED (Multi-Exit Discriminator). |
| 93 | * |
| 94 | * @param multiExitDisc the route MED (Multi-Exit Discriminator) to set |
| 95 | */ |
| 96 | void setMultiExitDisc(long multiExitDisc) { |
| 97 | this.multiExitDisc = multiExitDisc; |
| 98 | } |
| 99 | |
| 100 | /** |
| 101 | * Tests whether the route is originated from the local AS. |
| 102 | * <p/> |
| 103 | * The route is considered originated from the local AS if the AS Path |
| 104 | * is empty or if it begins with an AS_SET. |
| 105 | * |
| 106 | * @return true if the route is originated from the local AS, otherwise |
| 107 | * false |
| 108 | */ |
| 109 | boolean isLocalRoute() { |
| 110 | if (asPath.getPathSegments().isEmpty()) { |
| 111 | return true; |
| 112 | } |
| 113 | PathSegment firstPathSegment = asPath.getPathSegments().get(0); |
| 114 | if (firstPathSegment.getType() == BgpConstants.Update.AsPath.AS_SET) { |
| 115 | return true; |
| 116 | } |
| 117 | return false; |
| 118 | } |
| 119 | |
| 120 | /** |
| 121 | * Gets the BGP Neighbor AS number the route was received from. |
| 122 | * <p/> |
| 123 | * If the router is originated from the local AS, the return value is |
| 124 | * zero (BGP_AS_0). |
| 125 | * |
| 126 | * @return the BGP Neighbor AS number the route was received from. |
| 127 | */ |
| 128 | long getNeighborAs() { |
| 129 | if (isLocalRoute()) { |
| 130 | return BgpConstants.BGP_AS_0; |
| 131 | } |
| 132 | PathSegment firstPathSegment = asPath.getPathSegments().get(0); |
| 133 | if (firstPathSegment.getSegmentAsNumbers().isEmpty()) { |
| 134 | // TODO: Shouldn't happen. Should check during the parsing. |
| 135 | return BgpConstants.BGP_AS_0; |
| 136 | } |
| 137 | return firstPathSegment.getSegmentAsNumbers().get(0); |
| 138 | } |
| 139 | |
| 140 | /** |
| 141 | * Tests whether the AS Path contains a loop. |
| 142 | * <p/> |
| 143 | * The test is done by comparing whether the AS Path contains the |
| 144 | * local AS number. |
| 145 | * |
| 146 | * @param localAsNumber the local AS number to compare against |
| 147 | * @return true if the AS Path contains a loop, otherwise false |
| 148 | */ |
| 149 | boolean hasAsPathLoop(long localAsNumber) { |
| 150 | for (PathSegment pathSegment : asPath.getPathSegments()) { |
| 151 | for (Long asNumber : pathSegment.getSegmentAsNumbers()) { |
| 152 | if (asNumber.equals(localAsNumber)) { |
| 153 | return true; |
| 154 | } |
| 155 | } |
| 156 | } |
| 157 | return false; |
| 158 | } |
| 159 | |
| 160 | /** |
| 161 | * Compares this BGP route against another BGP route by using the |
| 162 | * BGP Decision Process. |
| 163 | * <p/> |
| 164 | * NOTE: The comparison needs to be performed only on routes that have |
| 165 | * same IP Prefix. |
| 166 | * |
| 167 | * @param other the BGP route to compare against |
| 168 | * @return true if this BGP route is better than the other BGP route |
| 169 | * or same, otherwise false |
| 170 | */ |
| 171 | boolean isBetterThan(BgpRouteEntry other) { |
| 172 | if (this == other) { |
| 173 | return true; // Return true if same route |
| 174 | } |
| 175 | |
| 176 | // Compare the LOCAL_PREF values: larger is better |
| 177 | if (getLocalPref() != other.getLocalPref()) { |
| 178 | return (getLocalPref() > other.getLocalPref()); |
| 179 | } |
| 180 | |
| 181 | // Compare the AS number in the path: smaller is better |
| 182 | if (getAsPath().getAsPathLength() != |
| 183 | other.getAsPath().getAsPathLength()) { |
| 184 | return getAsPath().getAsPathLength() < |
| 185 | other.getAsPath().getAsPathLength(); |
| 186 | } |
| 187 | |
| 188 | // Compare the Origin number: lower is better |
| 189 | if (getOrigin() != other.getOrigin()) { |
| 190 | return (getOrigin() < other.getOrigin()); |
| 191 | } |
| 192 | |
| 193 | // Compare the MED if the neighbor AS is same: larger is better |
| 194 | medLabel: { |
| 195 | boolean thisIsLocalRoute = isLocalRoute(); |
| 196 | if (thisIsLocalRoute != other.isLocalRoute()) { |
| 197 | break medLabel; // AS number is different |
| 198 | } |
| 199 | if (!thisIsLocalRoute) { |
| 200 | long thisNeighborAs = getNeighborAs(); |
| 201 | if (thisNeighborAs != other.getNeighborAs()) { |
| 202 | break medLabel; // AS number is different |
| 203 | } |
| 204 | if (thisNeighborAs == BgpConstants.BGP_AS_0) { |
| 205 | break medLabel; // Invalid AS number |
| 206 | } |
| 207 | } |
| 208 | |
| 209 | // Compare the MED |
| 210 | if (getMultiExitDisc() != other.getMultiExitDisc()) { |
| 211 | return (getMultiExitDisc() > other.getMultiExitDisc()); |
| 212 | } |
| 213 | } |
| 214 | |
| 215 | // Compare the peer BGP ID: lower is better |
| 216 | IpAddress peerBgpId = getBgpSession().getRemoteBgpId(); |
| 217 | IpAddress otherPeerBgpId = other.getBgpSession().getRemoteBgpId(); |
| 218 | if (!peerBgpId.equals(otherPeerBgpId)) { |
| 219 | return (peerBgpId.compareTo(otherPeerBgpId) < 0); |
| 220 | } |
| 221 | |
| 222 | // Compare the peer BGP address: lower is better |
| 223 | IpAddress peerAddress = getBgpSession().getRemoteIp4Address(); |
| 224 | IpAddress otherPeerAddress = |
| 225 | other.getBgpSession().getRemoteIp4Address(); |
| 226 | if (!peerAddress.equals(otherPeerAddress)) { |
| 227 | return (peerAddress.compareTo(otherPeerAddress) < 0); |
| 228 | } |
| 229 | |
| 230 | return true; // Routes are same. Shouldn't happen? |
| 231 | } |
| 232 | |
| 233 | /** |
| 234 | * A class to represent AS Path Segment. |
| 235 | */ |
| 236 | public static class PathSegment { |
| 237 | private final byte type; // Segment type: AS_SET, AS_SEQUENCE |
| 238 | private final ArrayList<Long> segmentAsNumbers; // Segment AS numbers |
| 239 | |
| 240 | /** |
| 241 | * Constructor. |
| 242 | * |
| 243 | * @param type the Path Segment Type: 1=AS_SET, 2=AS_SEQUENCE |
| 244 | * @param segmentAsNumbers the Segment AS numbers |
| 245 | */ |
| 246 | PathSegment(byte type, ArrayList<Long> segmentAsNumbers) { |
| 247 | this.type = type; |
| 248 | this.segmentAsNumbers = checkNotNull(segmentAsNumbers); |
| 249 | } |
| 250 | |
| 251 | /** |
| 252 | * Gets the Path Segment Type: AS_SET, AS_SEQUENCE. |
| 253 | * |
| 254 | * @return the Path Segment Type: AS_SET, AS_SEQUENCE |
| 255 | */ |
| 256 | public byte getType() { |
| 257 | return type; |
| 258 | } |
| 259 | |
| 260 | /** |
| 261 | * Gets the Path Segment AS Numbers. |
| 262 | * |
| 263 | * @return the Path Segment AS Numbers |
| 264 | */ |
| 265 | public ArrayList<Long> getSegmentAsNumbers() { |
| 266 | return segmentAsNumbers; |
| 267 | } |
| 268 | |
| 269 | @Override |
| 270 | public boolean equals(Object other) { |
| 271 | if (this == other) { |
| 272 | return true; |
| 273 | } |
| 274 | |
| 275 | if (!(other instanceof PathSegment)) { |
| 276 | return false; |
| 277 | } |
| 278 | |
| 279 | PathSegment otherPathSegment = (PathSegment) other; |
| 280 | return Objects.equals(this.type, otherPathSegment.type) && |
| 281 | Objects.equals(this.segmentAsNumbers, |
| 282 | otherPathSegment.segmentAsNumbers); |
| 283 | } |
| 284 | |
| 285 | @Override |
| 286 | public int hashCode() { |
| 287 | return Objects.hash(type, segmentAsNumbers); |
| 288 | } |
| 289 | |
| 290 | @Override |
| 291 | public String toString() { |
| 292 | return MoreObjects.toStringHelper(getClass()) |
| 293 | .add("type", this.type) |
| 294 | .add("segmentAsNumbers", this.segmentAsNumbers) |
| 295 | .toString(); |
| 296 | } |
| 297 | } |
| 298 | |
| 299 | /** |
| 300 | * A class to represent AS Path. |
| 301 | */ |
| 302 | public static class AsPath { |
| 303 | private final ArrayList<PathSegment> pathSegments; |
| 304 | private final int asPathLength; // Precomputed AS Path Length |
| 305 | |
| 306 | /** |
| 307 | * Constructor. |
| 308 | * |
| 309 | * @param pathSegments the Path Segments of the Path |
| 310 | */ |
| 311 | AsPath(ArrayList<PathSegment> pathSegments) { |
| 312 | this.pathSegments = checkNotNull(pathSegments); |
| 313 | |
| 314 | // |
| 315 | // Precompute the AS Path Length: |
| 316 | // - AS_SET counts as 1 |
| 317 | // |
| 318 | int pl = 0; |
| 319 | for (PathSegment pathSegment : pathSegments) { |
| 320 | if (pathSegment.getType() == |
| 321 | BgpConstants.Update.AsPath.AS_SET) { |
| 322 | pl++; |
| 323 | continue; |
| 324 | } |
| 325 | pl += pathSegment.getSegmentAsNumbers().size(); |
| 326 | } |
| 327 | asPathLength = pl; |
| 328 | } |
| 329 | |
| 330 | /** |
| 331 | * Gets the AS Path Segments. |
| 332 | * |
| 333 | * @return the AS Path Segments |
| 334 | */ |
| 335 | public ArrayList<PathSegment> getPathSegments() { |
| 336 | return pathSegments; |
| 337 | } |
| 338 | |
| 339 | /** |
| 340 | * Gets the AS Path Length as considered by the BGP Decision Process. |
| 341 | * |
| 342 | * @return the AS Path Length as considered by the BGP Decision Process |
| 343 | */ |
| 344 | int getAsPathLength() { |
| 345 | return asPathLength; |
| 346 | } |
| 347 | |
| 348 | @Override |
| 349 | public boolean equals(Object other) { |
| 350 | if (this == other) { |
| 351 | return true; |
| 352 | } |
| 353 | |
| 354 | if (!(other instanceof AsPath)) { |
| 355 | return false; |
| 356 | } |
| 357 | |
| 358 | AsPath otherAsPath = (AsPath) other; |
| 359 | return Objects.equals(this.pathSegments, otherAsPath.pathSegments); |
| 360 | } |
| 361 | |
| 362 | @Override |
| 363 | public int hashCode() { |
| 364 | return Objects.hash(pathSegments); |
| 365 | } |
| 366 | |
| 367 | @Override |
| 368 | public String toString() { |
| 369 | return MoreObjects.toStringHelper(getClass()) |
| 370 | .add("pathSegments", this.pathSegments) |
| 371 | .toString(); |
| 372 | } |
| 373 | } |
| 374 | |
| 375 | /** |
| 376 | * Compares whether two objects are equal. |
| 377 | * <p/> |
| 378 | * NOTE: The bgpSession field is excluded from the comparison. |
| 379 | * |
| 380 | * @return true if the two objects are equal, otherwise false. |
| 381 | */ |
| 382 | @Override |
| 383 | public boolean equals(Object other) { |
| 384 | if (this == other) { |
| 385 | return true; |
| 386 | } |
| 387 | |
| 388 | // |
| 389 | // NOTE: Subclasses are considered as change of identity, hence |
| 390 | // equals() will return false if the class type doesn't match. |
| 391 | // |
| 392 | if (other == null || getClass() != other.getClass()) { |
| 393 | return false; |
| 394 | } |
| 395 | |
| 396 | if (!super.equals(other)) { |
| 397 | return false; |
| 398 | } |
| 399 | |
| 400 | // NOTE: The bgpSession field is excluded from the comparison |
| 401 | BgpRouteEntry otherRoute = (BgpRouteEntry) other; |
| 402 | return (this.origin == otherRoute.origin) && |
| 403 | Objects.equals(this.asPath, otherRoute.asPath) && |
| 404 | (this.localPref == otherRoute.localPref) && |
| 405 | (this.multiExitDisc == otherRoute.multiExitDisc); |
| 406 | } |
| 407 | |
| 408 | /** |
| 409 | * Computes the hash code. |
| 410 | * <p/> |
| 411 | * NOTE: We return the base class hash code to avoid expensive computation |
| 412 | * |
| 413 | * @return the object hash code |
| 414 | */ |
| 415 | @Override |
| 416 | public int hashCode() { |
| 417 | return super.hashCode(); |
| 418 | } |
| 419 | |
| 420 | @Override |
| 421 | public String toString() { |
| 422 | return MoreObjects.toStringHelper(getClass()) |
| 423 | .add("prefix", prefix()) |
| 424 | .add("nextHop", nextHop()) |
| 425 | .add("bgpId", bgpSession.getRemoteBgpId()) |
| 426 | .add("origin", origin) |
| 427 | .add("asPath", asPath) |
| 428 | .add("localPref", localPref) |
| 429 | .add("multiExitDisc", multiExitDisc) |
| 430 | .toString(); |
| 431 | } |
| 432 | } |