Examples with GraphEdge org.batfish.symbolic.GraphEdge used on opensource projects

Example 16 with GraphEdge

use of org.batfish.symbolic.GraphEdge in project batfish by batfish.

the class PropertyAdder method instrumentLoop.

/*
   * Instruments the network to check if a router will be part
   * of a routing loop.
   */
BoolExpr instrumentLoop(String router) {
    Context ctx = _encoderSlice.getCtx();
    Solver solver = _encoderSlice.getSolver();
    String sliceName = _encoderSlice.getSliceName();
    // Add on-loop variables to track a loop
    Map<String, BoolExpr> onLoop = new HashMap<>();
    Graph graph = _encoderSlice.getGraph();
    for (String r : graph.getRouters()) {
        String name = _encoderSlice.getEncoder().getId() + "_" + sliceName + "_on-loop_" + router + "_" + r;
        BoolExpr var = ctx.mkBoolConst(name);
        onLoop.put(r, var);
        _encoderSlice.getAllVariables().put(var.toString(), var);
    }
    for (Entry<String, List<GraphEdge>> entry : graph.getEdgeMap().entrySet()) {
        String r = entry.getKey();
        List<GraphEdge> edges = entry.getValue();
        BoolExpr var = onLoop.get(r);
        BoolExpr acc = ctx.mkBool(false);
        for (GraphEdge edge : edges) {
            if (!edge.isAbstract()) {
                BoolExpr fwd = _encoderSlice.getForwardsAcross().get(r, edge);
                String peer = edge.getPeer();
                if (peer != null) {
                    if (peer.equals(router)) {
                        // If next hop is static route router, then on loop
                        acc = ctx.mkOr(acc, fwd);
                    } else {
                        // Otherwise check if next hop also is on the loop
                        BoolExpr peerOnLoop = onLoop.get(peer);
                        acc = ctx.mkOr(acc, ctx.mkAnd(fwd, peerOnLoop));
                    }
                }
            }
        }
        solver.add(ctx.mkEq(var, acc));
    }
    return onLoop.get(router);
}

Example 17 with GraphEdge

use of org.batfish.symbolic.GraphEdge in project batfish by batfish.

the class PropertyChecker method inferDestinationHeaderSpace.

private void inferDestinationHeaderSpace(Graph g, Collection<GraphEdge> destPorts, HeaderLocationQuestion q) {
    // Skip inference if the destination IP headerspace does not need to be inferred.
    if (!q.getHeaderSpace().getDstIps().isEmpty()) {
        return;
    }
    // Infer relevant destination IP headerspace from interfaces
    HeaderSpace headerSpace = q.getHeaderSpace();
    for (GraphEdge ge : destPorts) {
        // it can be any prefix, so we leave it unconstrained
        if (g.isExternal(ge)) {
            headerSpace.setDstIps(Collections.emptySet());
            headerSpace.setNotDstIps(Collections.emptySet());
            break;
        }
        // If we don't know what is on the other end
        if (ge.getPeer() == null) {
            Prefix pfx = ge.getStart().getAddress().getPrefix();
            IpWildcard dst = new IpWildcard(pfx);
            headerSpace.setDstIps(Iterables.concat(headerSpace.getDstIps(), Collections.singleton(dst)));
        } else {
            // If host, add the subnet but not the neighbor's address
            if (g.isHost(ge.getRouter())) {
                Prefix pfx = ge.getStart().getAddress().getPrefix();
                IpWildcard dst = new IpWildcard(pfx);
                headerSpace.setDstIps(Iterables.concat(headerSpace.getDstIps(), Collections.singleton(dst)));
                Ip ip = ge.getEnd().getAddress().getIp();
                IpWildcard dst2 = new IpWildcard(ip);
                headerSpace.setNotDstIps(Iterables.concat(headerSpace.getNotDstIps(), Collections.singleton(dst2)));
            } else {
                // Otherwise, we add the exact address
                Ip ip = ge.getStart().getAddress().getIp();
                IpWildcard dst = new IpWildcard(ip);
                headerSpace.setDstIps(Iterables.concat(headerSpace.getDstIps(), Collections.singleton(dst)));
            }
        }
    }
}

Example 18 with GraphEdge

use of org.batfish.symbolic.GraphEdge in project batfish by batfish.

the class PropertyChecker method relateFailures.

private BoolExpr relateFailures(Encoder enc1, Encoder enc2) {
    BoolExpr related = enc1.mkTrue();
    for (GraphEdge ge : enc1.getMainSlice().getGraph().getAllRealEdges()) {
        ArithExpr a1 = enc1.getSymbolicFailures().getFailedVariable(ge);
        ArithExpr a2 = enc2.getSymbolicFailures().getFailedVariable(ge);
        assert a1 != null;
        assert a2 != null;
        related = enc1.mkEq(a1, a2);
    }
    return related;
}

Example 19 with GraphEdge

use of org.batfish.symbolic.GraphEdge in project batfish by batfish.

the class PropertyChecker method checkBlackHole.

/*
   * Compute if there can ever be a black hole for routers that are
   * not at the edge of the network. This is almost certainly a bug.
   */
public AnswerElement checkBlackHole(HeaderQuestion q) {
    Graph graph = new Graph(_batfish);
    Encoder enc = new Encoder(_settings, graph, q);
    enc.computeEncoding();
    Context ctx = enc.getCtx();
    EncoderSlice slice = enc.getMainSlice();
    // Collect routers that have no host/environment edge
    List<String> toCheck = new ArrayList<>();
    for (Entry<String, List<GraphEdge>> entry : graph.getEdgeMap().entrySet()) {
        String router = entry.getKey();
        List<GraphEdge> edges = entry.getValue();
        boolean check = true;
        for (GraphEdge edge : edges) {
            if (edge.getEnd() == null) {
                check = false;
                break;
            }
        }
        if (check) {
            toCheck.add(router);
        }
    }
    // Ensure the router never receives traffic and then drops the traffic
    BoolExpr someBlackHole = ctx.mkBool(false);
    for (String router : toCheck) {
        Map<GraphEdge, BoolExpr> edges = slice.getSymbolicDecisions().getDataForwarding().get(router);
        BoolExpr doesNotFwd = ctx.mkBool(true);
        for (Map.Entry<GraphEdge, BoolExpr> entry : edges.entrySet()) {
            BoolExpr dataFwd = entry.getValue();
            doesNotFwd = ctx.mkAnd(doesNotFwd, ctx.mkNot(dataFwd));
        }
        BoolExpr isFwdTo = ctx.mkBool(false);
        Set<String> neighbors = graph.getNeighbors().get(router);
        for (String n : neighbors) {
            for (Map.Entry<GraphEdge, BoolExpr> entry : slice.getSymbolicDecisions().getDataForwarding().get(n).entrySet()) {
                GraphEdge ge = entry.getKey();
                BoolExpr fwd = entry.getValue();
                if (router.equals(ge.getPeer())) {
                    isFwdTo = ctx.mkOr(isFwdTo, fwd);
                }
            }
        }
        someBlackHole = ctx.mkOr(someBlackHole, ctx.mkAnd(isFwdTo, doesNotFwd));
    }
    enc.add(someBlackHole);
    VerificationResult result = enc.verify().getFirst();
    return new SmtOneAnswerElement(result);
}

Example 20 with GraphEdge

use of org.batfish.symbolic.GraphEdge in project batfish by batfish.

the class CounterExample method buildFlowTrace.

/*
   * Build flow information for a given hop along a path
   */
Tuple<Flow, FlowTrace> buildFlowTrace(Encoder enc, String router) {
    EncoderSlice slice = enc.getMainSlice();
    SymbolicPacket pkt = slice.getSymbolicPacket();
    SymbolicDecisions decisions = slice.getSymbolicDecisions();
    Flow f = buildFlow(pkt, router);
    SortedSet<String> visited = new TreeSet<>();
    List<FlowTraceHop> hops = new ArrayList<>();
    String current = router;
    while (true) {
        visited.add(current);
        // Get the forwarding variables
        Map<GraphEdge, BoolExpr> dfwd = decisions.getDataForwarding().get(current);
        Map<GraphEdge, BoolExpr> cfwd = decisions.getControlForwarding().get(current);
        Map<GraphEdge, BoolExpr> across = enc.getMainSlice().getForwardsAcross().get(current);
        // Find the route used
        SymbolicRoute r = decisions.getBestNeighbor().get(current);
        Protocol proto = buildProcotol(r, slice, current);
        Prefix pfx = buildPrefix(r, f);
        // pick the next router
        boolean found = false;
        for (Entry<GraphEdge, BoolExpr> entry : dfwd.entrySet()) {
            GraphEdge ge = entry.getKey();
            BoolExpr dexpr = entry.getValue();
            BoolExpr cexpr = cfwd.get(ge);
            BoolExpr aexpr = across.get(ge);
            String route = buildRoute(pfx, proto, ge);
            if (isTrue(dexpr)) {
                hops.add(buildFlowTraceHop(ge, route));
                if (ge.getPeer() != null && visited.contains(ge.getPeer())) {
                    FlowTrace ft = new FlowTrace(FlowDisposition.LOOP, hops, "LOOP");
                    return new Tuple<>(f, ft);
                }
                if (isFalse(aexpr)) {
                    Interface i = ge.getEnd();
                    IpAccessList acl = i.getIncomingFilter();
                    FilterResult fr = acl.filter(f);
                    String line = "default deny";
                    if (fr.getMatchLine() != null) {
                        line = acl.getLines().get(fr.getMatchLine()).getName();
                    }
                    String note = String.format("DENIED_IN{%s}{%s}", acl.getName(), line);
                    FlowTrace ft = new FlowTrace(FlowDisposition.DENIED_IN, hops, note);
                    return new Tuple<>(f, ft);
                }
                boolean isLoopback = slice.getGraph().isLoopback(ge);
                if (isLoopback) {
                    FlowTrace ft = new FlowTrace(FlowDisposition.ACCEPTED, hops, "ACCEPTED");
                    return new Tuple<>(f, ft);
                }
                if (ge.getPeer() == null) {
                    boolean isBgpPeering = slice.getGraph().getEbgpNeighbors().get(ge) != null;
                    if (isBgpPeering) {
                        FlowTrace ft = new FlowTrace(FlowDisposition.ACCEPTED, hops, "ACCEPTED");
                        return new Tuple<>(f, ft);
                    } else {
                        FlowTrace ft = new FlowTrace(FlowDisposition.NEIGHBOR_UNREACHABLE_OR_EXITS_NETWORK, hops, "NEIGHBOR_UNREACHABLE_OR_EXITS_NETWORK");
                        return new Tuple<>(f, ft);
                    }
                }
                if (slice.getGraph().isHost(ge.getPeer())) {
                    FlowTrace ft = new FlowTrace(FlowDisposition.ACCEPTED, hops, "ACCEPTED");
                    return new Tuple<>(f, ft);
                }
                current = ge.getPeer();
                found = true;
                break;
            } else if (isTrue(cexpr)) {
                hops.add(buildFlowTraceHop(ge, route));
                Interface i = ge.getStart();
                IpAccessList acl = i.getOutgoingFilter();
                FilterResult fr = acl.filter(f);
                IpAccessListLine line = acl.getLines().get(fr.getMatchLine());
                String note = String.format("DENIED_OUT{%s}{%s}", acl.getName(), line.getName());
                FlowTrace ft = new FlowTrace(FlowDisposition.DENIED_OUT, hops, note);
                return new Tuple<>(f, ft);
            }
        }
        if (!found) {
            BoolExpr permitted = r.getPermitted();
            if (boolVal(permitted)) {
                // Check if there is an accepting interface
                for (GraphEdge ge : slice.getGraph().getEdgeMap().get(current)) {
                    Interface i = ge.getStart();
                    Ip ip = i.getAddress().getIp();
                    if (ip.equals(f.getDstIp())) {
                        FlowTrace ft = new FlowTrace(FlowDisposition.ACCEPTED, hops, "ACCEPTED");
                        return new Tuple<>(f, ft);
                    }
                }
                FlowTrace ft = new FlowTrace(FlowDisposition.NEIGHBOR_UNREACHABLE_OR_EXITS_NETWORK, hops, "NEIGHBOR_UNREACHABLE_OR_EXITS_NETWORK");
                return new Tuple<>(f, ft);
            }
            FlowTrace ft = new FlowTrace(FlowDisposition.NO_ROUTE, hops, "NO_ROUTE");
            return new Tuple<>(f, ft);
        }
    }
}