Examples with FlowProcessor org.batfish.common.plugin.FlowProcessor used on opensource projects

Example 1 with FlowProcessor

use of org.batfish.common.plugin.FlowProcessor in project batfish by batfish.

the class CommonUtil method initRemoteBgpNeighbors.

/**
 * Initialize BGP neighbors for all nodes.
 *
 * @param configurations map of all configurations, keyed by hostname
 * @param ipOwners mapping of Ips to a set of nodes (hostnames) that owns those IPs
 * @param checkReachability whether bgp neighbor reachability should be checked
 * @param flowProcessor dataplane plugin to use to check reachability. Must not be {@code null} if
 *     {@code checkReachability = true}
 * @param dp dataplane to use to check reachability. Must not be {@code null} if {@code
 *     checkReachability = true}
 */
public static void initRemoteBgpNeighbors(Map<String, Configuration> configurations, Map<Ip, Set<String>> ipOwners, boolean checkReachability, @Nullable FlowProcessor flowProcessor, @Nullable DataPlane dp) {
    // TODO: handle duplicate ips on different vrfs
    Map<BgpNeighbor, Ip> remoteAddresses = new IdentityHashMap<>();
    Map<Ip, Set<BgpNeighbor>> localAddresses = new HashMap<>();
    /*
     * Construct maps indicating which neighbor owns which Ip Address
     */
    for (Configuration node : configurations.values()) {
        String hostname = node.getHostname();
        for (Vrf vrf : node.getVrfs().values()) {
            BgpProcess proc = vrf.getBgpProcess();
            if (proc == null) {
                // nothing to do if no bgp process on this VRF
                continue;
            }
            for (BgpNeighbor bgpNeighbor : proc.getNeighbors().values()) {
                /*
           * Begin by initializing candidate neighbors to an empty set
           */
                bgpNeighbor.initCandidateRemoteBgpNeighbors();
                // Skip things we don't handle
                if (bgpNeighbor.getPrefix().getPrefixLength() < Prefix.MAX_PREFIX_LENGTH) {
                    throw new BatfishException(hostname + ": Do not support dynamic bgp sessions at this time: " + bgpNeighbor.getPrefix());
                }
                Ip remoteAddress = bgpNeighbor.getAddress();
                if (remoteAddress == null) {
                    throw new BatfishException(hostname + ": Could not determine remote address of bgp neighbor: " + bgpNeighbor);
                }
                Ip localAddress = bgpNeighbor.getLocalIp();
                if (localAddress == null || !ipOwners.containsKey(localAddress) || !ipOwners.get(localAddress).contains(hostname)) {
                    // Local address is not owned by anybody
                    continue;
                }
                remoteAddresses.put(bgpNeighbor, remoteAddress);
                // Add this neighbor as owner of its local address
                localAddresses.computeIfAbsent(localAddress, k -> Collections.newSetFromMap(new IdentityHashMap<>())).add(bgpNeighbor);
            }
        }
    }
    /*
     * For each neighbor, construct the set of candidate neighbors, then filter out impossible
     * sessions.
     */
    for (Entry<BgpNeighbor, Ip> e : remoteAddresses.entrySet()) {
        BgpNeighbor bgpNeighbor = e.getKey();
        Ip remoteAddress = e.getValue();
        Ip localAddress = bgpNeighbor.getLocalIp();
        int localLocalAs = bgpNeighbor.getLocalAs();
        int localRemoteAs = bgpNeighbor.getRemoteAs();
        /*
       * Let the set of candidate neighbors be set of neighbors that own the remoteAddress
       */
        Set<BgpNeighbor> remoteBgpNeighborCandidates = localAddresses.get(remoteAddress);
        if (remoteBgpNeighborCandidates == null) {
            // No possible remote neighbors
            continue;
        }
        /*
       * Filter the set of candidate neighbors based on these checks:
       * - Remote neighbor's remote address is the same as our local address
       * - Remote neighbor's remote AS is the same as our local AS (and vice-versa)
       */
        for (BgpNeighbor remoteBgpNeighborCandidate : remoteBgpNeighborCandidates) {
            int remoteLocalAs = remoteBgpNeighborCandidate.getLocalAs();
            int remoteRemoteAs = remoteBgpNeighborCandidate.getRemoteAs();
            Ip reciprocalRemoteIp = remoteBgpNeighborCandidate.getAddress();
            if (localAddress.equals(reciprocalRemoteIp) && localLocalAs == remoteRemoteAs && localRemoteAs == remoteLocalAs) {
                /*
           * Fairly confident establishing the session is possible here, but still check
           * reachability if needed.
           * We should check reachability only for eBgp multihop or iBgp
           */
                if (checkReachability && (bgpNeighbor.getEbgpMultihop() || localLocalAs == remoteLocalAs)) {
                    /*
             * Ensure that the session can be established by running traceroute in both directions
             */
                    if (flowProcessor == null || dp == null) {
                        throw new BatfishException("Cannot compute neighbor reachability without a dataplane");
                    }
                    Flow.Builder fb = new Flow.Builder();
                    fb.setIpProtocol(IpProtocol.TCP);
                    fb.setTag("neighbor-resolution");
                    fb.setIngressNode(bgpNeighbor.getOwner().getHostname());
                    fb.setSrcIp(localAddress);
                    fb.setDstIp(remoteAddress);
                    fb.setSrcPort(NamedPort.EPHEMERAL_LOWEST.number());
                    fb.setDstPort(NamedPort.BGP.number());
                    Flow forwardFlow = fb.build();
                    fb.setIngressNode(remoteBgpNeighborCandidate.getOwner().getHostname());
                    fb.setSrcIp(forwardFlow.getDstIp());
                    fb.setDstIp(forwardFlow.getSrcIp());
                    fb.setSrcPort(forwardFlow.getDstPort());
                    fb.setDstPort(forwardFlow.getSrcPort());
                    Flow backwardFlow = fb.build();
                    SortedMap<Flow, Set<FlowTrace>> traces = flowProcessor.processFlows(dp, ImmutableSet.of(forwardFlow, backwardFlow));
                    if (traces.values().stream().map(fts -> fts.stream().allMatch(ft -> ft.getDisposition() != FlowDisposition.ACCEPTED)).anyMatch(Predicate.isEqual(true))) {
                        /*
               * If either flow has all traceroutes fail, do not consider the neighbor valid
               */
                        continue;
                    }
                    bgpNeighbor.getCandidateRemoteBgpNeighbors().add(remoteBgpNeighborCandidate);
                } else {
                    bgpNeighbor.getCandidateRemoteBgpNeighbors().add(remoteBgpNeighborCandidate);
                }
            }
        }
        Set<BgpNeighbor> finalCandidates = bgpNeighbor.getCandidateRemoteBgpNeighbors();
        if (finalCandidates.size() > 1) {
            /* If we still have not narrowed it down to a single neighbor,
         * pick based on sorted hostnames
         */
            SortedMap<String, BgpNeighbor> hostnameToNeighbor = finalCandidates.stream().collect(ImmutableSortedMap.toImmutableSortedMap(String::compareTo, k -> k.getOwner().getHostname(), Function.identity()));
            bgpNeighbor.setRemoteBgpNeighbor(hostnameToNeighbor.get(hostnameToNeighbor.firstKey()));
        } else if (finalCandidates.size() == 1) {
            bgpNeighbor.setRemoteBgpNeighbor(finalCandidates.iterator().next());
        } else {
            bgpNeighbor.setRemoteBgpNeighbor(null);
        }
    }
}