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Diffstat (limited to 'framework/src/onos/bgp/ctl/src/main/java/org/onosproject/bgp/controller/impl/BgpSelectionAlgo.java')
| -rw-r--r-- | framework/src/onos/bgp/ctl/src/main/java/org/onosproject/bgp/controller/impl/BgpSelectionAlgo.java | 242 |
1 files changed, 242 insertions, 0 deletions
diff --git a/framework/src/onos/bgp/ctl/src/main/java/org/onosproject/bgp/controller/impl/BgpSelectionAlgo.java b/framework/src/onos/bgp/ctl/src/main/java/org/onosproject/bgp/controller/impl/BgpSelectionAlgo.java new file mode 100644 index 00000000..d3065f43 --- /dev/null +++ b/framework/src/onos/bgp/ctl/src/main/java/org/onosproject/bgp/controller/impl/BgpSelectionAlgo.java @@ -0,0 +1,242 @@ +/* + * Copyright 2015 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.bgp.controller.impl; + +import java.util.Comparator; +import java.util.List; +import java.util.ListIterator; + +import org.onosproject.bgpio.protocol.linkstate.PathAttrNlriDetailsLocalRib; +import org.onosproject.bgpio.types.AsPath; +import org.onosproject.bgpio.types.BgpValueType; +import org.onosproject.bgpio.types.LocalPref; +import org.onosproject.bgpio.types.Med; +import org.onosproject.bgpio.types.Origin; +import org.onosproject.bgpio.types.Origin.ORIGINTYPE; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +/** + * Implementation of BGP best path Selection process. + */ +public final class BgpSelectionAlgo implements Comparator<PathAttrNlriDetailsLocalRib> { + private static final Logger log = LoggerFactory.getLogger(BgpSelectionAlgo.class); + LocalPref obj1LocPref = null; + AsPath obj1Aspath = null; + Origin obj1Origin = null; + Med obj1Med = null; + LocalPref obj2LocPref = null; + AsPath obj2Aspath = null; + Origin obj2Origin = null; + Med obj2Med = null; + + @Override + public int compare(PathAttrNlriDetailsLocalRib pathNlriDetails1, PathAttrNlriDetailsLocalRib pathNlriDetails2) { + if (pathNlriDetails1 == null) { + return -1; + } + if (pathNlriDetails2 == null) { + return 1; + } + if (pathNlriDetails1.equals(pathNlriDetails2)) { + return 0; + } + + List<BgpValueType> o1 = pathNlriDetails1.localRibNlridetails().pathAttributes(); + List<BgpValueType> o2 = pathNlriDetails2.localRibNlridetails().pathAttributes(); + ListIterator<BgpValueType> listIteratorObj1 = o1.listIterator(); + ListIterator<BgpValueType> listIteratorObj2 = o2.listIterator(); + storeAttr(listIteratorObj1, listIteratorObj2); + + // prefer attribute with higher local preference + if (obj1LocPref != null || obj2LocPref != null && (obj1LocPref != null && !obj1LocPref.equals(obj2LocPref))) { + return compareLocalPref(obj1LocPref, obj2LocPref); + } + + // prefer attribute with shortest Aspath + if (!obj1Aspath.equals(obj2Aspath)) { + Integer obj1Size = countASSize(obj1Aspath); + Integer obj2Size = countASSize(obj2Aspath); + if (obj1Size != obj2Size) { + return compareAsPath(obj1Size, obj2Size); + } + } + + // prefer attribute with lowest origin type + if (!obj1Origin.equals(obj2Origin)) { + return compareOrigin(obj1Origin, obj2Origin); + } + + // prefer attribute with lowest MED + if (obj1Med != null || obj2Med != null && (obj1Med != null && !obj1Med.equals(obj2Med))) { + return compareMed(obj1Med, obj2Med); + } + + if ((pathNlriDetails1 != null || pathNlriDetails2 != null) && (pathNlriDetails1 != null && !pathNlriDetails1 + .equals(pathNlriDetails2))) { + return comparePeerDetails(pathNlriDetails1, pathNlriDetails2); + } + return 0; + } + + /** + * Compares local preference of two objects and returns object with higher preference. + * + * @param obj1LocPref local preference object1 + * @param obj2LocPref local preference object2 + * @return object with higher preference + */ + int compareLocalPref(LocalPref obj1LocPref, LocalPref obj2LocPref) { + return ((Integer) (obj1LocPref.localPref())).compareTo((Integer) (obj2LocPref.localPref())); + } + + /** + * Compares AsPath of two objects and returns object with shortest AsPath. + * + * @param obj1Size object1 AS count + * @param obj2Size object2 AS count + * @return + */ + int compareAsPath(Integer obj1Size, Integer obj2Size) { + return obj1Size.compareTo(obj2Size); + } + + /** + * Compare Origin of two objects and returns object with lowest origin value. + * + * @param obj1Origin Origin object1 + * @param obj2Origin Origin object1 + * @return object with lowest origin value + */ + int compareOrigin(Origin obj1Origin, Origin obj2Origin) { + if (obj1Origin.origin() == ORIGINTYPE.IGP) { + return 1; + } + if (obj2Origin.origin() == ORIGINTYPE.IGP) { + return -1; + } + if (obj1Origin.origin() == ORIGINTYPE.EGP) { + return 1; + } else { + return -1; + } + } + + /** + * Compare Med of two objects and returns object with lowestMed value. + * + * @param obj1Med Med object1 + * @param obj2Med Med object2 + * @return returns object with lowestMed value + */ + int compareMed(Med obj1Med, Med obj2Med) { + return ((Integer) (obj2Med.med())).compareTo((Integer) (obj1Med.med())); + } + + /** + * Compares EBGP over IBGP, BGP identifier value and peer address. + * + * @param pathNlriDetails1 PathAttrNlriDetailsLocalRib object1 + * @param pathNlriDetails2 PathAttrNlriDetailsLocalRib object2 + * @return object which as EBGP over IBGP, lowest BGP identifier value and lowest peer address + */ + int comparePeerDetails(PathAttrNlriDetailsLocalRib pathNlriDetails1, PathAttrNlriDetailsLocalRib pathNlriDetails2) { + // consider EBGP over IBGP + if (pathNlriDetails1.isLocalRibIbgpSession() != pathNlriDetails2.isLocalRibIbgpSession()) { + if (pathNlriDetails1 == null || pathNlriDetails1.isLocalRibIbgpSession()) { + return -1; + } + if (pathNlriDetails2 == null || pathNlriDetails2.isLocalRibIbgpSession()) { + return 1; + } + } + // prefer lowest BGP identifier value. + if (pathNlriDetails1.localRibIdentifier() != pathNlriDetails2.localRibIdentifier()) { + return ((Integer) pathNlriDetails2.localRibIdentifier()) + .compareTo(pathNlriDetails1.localRibIdentifier()); + } + //prefer lowest peer address + if (pathNlriDetails1.localRibIpAddress() != pathNlriDetails2.localRibIpAddress()) { + return pathNlriDetails2.localRibIpAddress().compareTo(pathNlriDetails1.localRibIpAddress()); + } + return 0; + } + + /** + * Returns ASes count of AsPath attribute , if AS_SET is present then count as 1. + * + * @param aspath object of AsPath + * @return count of ASes + */ + Integer countASSize(AsPath aspath) { + boolean isASSet = false; + int count = 0; + if (!aspath.asPathSet().isEmpty()) { + isASSet = true; + } + if (!aspath.asPathSeq().isEmpty()) { + count = aspath.asPathSeq().size(); + } + return isASSet ? ++count : count; + } + + /** + * Stores BGP basic attributes of two objects. + * + * @param listIteratorObj1 list iterator of object1 + * @param listIteratorObj2 list iterator of object2 + */ + void storeAttr(ListIterator<BgpValueType> listIteratorObj1, ListIterator<BgpValueType> listIteratorObj2) { + while (listIteratorObj1.hasNext()) { + BgpValueType pathAttributeObj1 = listIteratorObj1.next(); + switch (pathAttributeObj1.getType()) { + case LocalPref.LOCAL_PREF_TYPE: + obj1LocPref = (LocalPref) pathAttributeObj1; + break; + case AsPath.ASPATH_TYPE: + obj1Aspath = (AsPath) pathAttributeObj1; + break; + case Origin.ORIGIN_TYPE: + obj1Origin = (Origin) pathAttributeObj1; + break; + case Med.MED_TYPE: + obj1Med = (Med) pathAttributeObj1; + break; + default: + log.debug("Got other type, Not required: " + pathAttributeObj1.getType()); + } + } + while (listIteratorObj2.hasNext()) { + BgpValueType pathAttributeObj2 = listIteratorObj2.next(); + switch (pathAttributeObj2.getType()) { + case LocalPref.LOCAL_PREF_TYPE: + obj2LocPref = (LocalPref) pathAttributeObj2; + break; + case AsPath.ASPATH_TYPE: + obj2Aspath = (AsPath) pathAttributeObj2; + break; + case Origin.ORIGIN_TYPE: + obj2Origin = (Origin) pathAttributeObj2; + break; + case Med.MED_TYPE: + obj2Med = (Med) pathAttributeObj2; + break; + default: + log.debug("Got other type, Not required: " + pathAttributeObj2.getType()); + } + } + } +}
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