Examples with BoolExpr com.microsoft.z3.BoolExpr used on opensource projects

Example 66 with BoolExpr

use of com.microsoft.z3.BoolExpr 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);
        }
    }
}

Example 67 with BoolExpr

use of com.microsoft.z3.BoolExpr in project batfish by batfish.

the class CounterExample method buildFlowHistoryDiff.

/*
   * Create a trace-based counterexample demonstrating
   * the difference between two networks on a single packet.
   */
FlowHistory buildFlowHistoryDiff(String testRigName, Collection<String> sourceRouters, Encoder enc, Encoder enc2, Map<String, BoolExpr> reach, Map<String, BoolExpr> reach2) {
    FlowHistory fh = new FlowHistory();
    assert (reach2 != null);
    for (String source : sourceRouters) {
        BoolExpr sourceVar1 = reach.get(source);
        BoolExpr sourceVar2 = reach2.get(source);
        String val1 = evaluate(sourceVar1);
        String val2 = evaluate(sourceVar2);
        if (!Objects.equals(val1, val2)) {
            Tuple<Flow, FlowTrace> diff = buildFlowTrace(enc, source);
            Tuple<Flow, FlowTrace> base = buildFlowTrace(enc2, source);
            SortedSet<Edge> failedLinksDiff = buildFailedLinks(enc);
            SortedSet<Edge> failedLinksBase = buildFailedLinks(enc2);
            SortedSet<BgpAdvertisement> envRoutesDiff = buildEnvRoutingTable(enc);
            SortedSet<BgpAdvertisement> envRoutesBase = buildEnvRoutingTable(enc2);
            Environment baseEnv = new Environment("BASE", testRigName, failedLinksBase, null, null, null, null, envRoutesBase);
            Environment failedEnv = new Environment("DELTA", testRigName, failedLinksDiff, null, null, null, null, envRoutesDiff);
            fh.addFlowTrace(base.getFirst(), "BASE", baseEnv, base.getSecond());
            fh.addFlowTrace(diff.getFirst(), "DELTA", failedEnv, diff.getSecond());
        }
    }
    return fh;
}

Example 68 with BoolExpr

use of com.microsoft.z3.BoolExpr in project batfish by batfish.

the class CounterExample method buildEnvRoutingTable.

SortedSet<BgpAdvertisement> buildEnvRoutingTable(Encoder enc) {
    SortedSet<BgpAdvertisement> routes = new TreeSet<>();
    EncoderSlice slice = enc.getMainSlice();
    LogicalGraph lg = slice.getLogicalGraph();
    for (Entry<LogicalEdge, SymbolicRoute> entry : lg.getEnvironmentVars().entrySet()) {
        LogicalEdge lge = entry.getKey();
        SymbolicRoute record = entry.getValue();
        // If there is an external advertisement
        if (boolVal(record.getPermitted())) {
            // If we actually use it
            GraphEdge ge = lge.getEdge();
            String router = ge.getRouter();
            SymbolicDecisions decisions = slice.getSymbolicDecisions();
            BoolExpr ctrFwd = decisions.getControlForwarding().get(router, ge);
            assert ctrFwd != null;
            if (boolVal(ctrFwd)) {
                SymbolicRoute r = decisions.getBestNeighbor().get(router);
                SymbolicPacket pkt = slice.getSymbolicPacket();
                Flow f = buildFlow(pkt, router);
                Prefix pfx = buildPrefix(r, f);
                int pathLength = intVal(r.getMetric());
                // Create dummy information
                BgpNeighbor n = slice.getGraph().getEbgpNeighbors().get(lge.getEdge());
                String srcNode = "as" + n.getRemoteAs();
                Ip zeroIp = new Ip(0);
                Ip dstIp = n.getLocalIp();
                // Recover AS path
                List<SortedSet<Integer>> asSets = new ArrayList<>();
                for (int i = 0; i < pathLength; i++) {
                    SortedSet<Integer> asSet = new TreeSet<>();
                    asSet.add(-1);
                    asSets.add(asSet);
                }
                AsPath path = new AsPath(asSets);
                // Recover communities
                SortedSet<Long> communities = new TreeSet<>();
                for (Entry<CommunityVar, BoolExpr> entry2 : r.getCommunities().entrySet()) {
                    CommunityVar cvar = entry2.getKey();
                    BoolExpr expr = entry2.getValue();
                    if (cvar.getType() == Type.EXACT && boolVal(expr)) {
                        communities.add(cvar.asLong());
                    }
                }
                BgpAdvertisement adv = new BgpAdvertisement(BgpAdvertisementType.EBGP_RECEIVED, pfx, zeroIp, srcNode, "default", zeroIp, router, "default", dstIp, RoutingProtocol.BGP, OriginType.EGP, 100, 80, zeroIp, path, communities, new TreeSet<>(), 0);
                routes.add(adv);
            }
        }
    }
    return routes;
}

Example 69 with BoolExpr

use of com.microsoft.z3.BoolExpr in project batfish by batfish.

the class PropertyChecker method checkDeterminism.

/*
   * Check if there exist multiple stable solutions to the network.
   * If so, reports the forwarding differences between the two cases.
   */
public AnswerElement checkDeterminism(HeaderQuestion q) {
    Graph graph = new Graph(_batfish);
    Encoder enc1 = new Encoder(_settings, graph, q);
    Encoder enc2 = new Encoder(enc1, graph, q);
    enc1.computeEncoding();
    enc2.computeEncoding();
    addEnvironmentConstraints(enc1, q.getBaseEnvironmentType());
    BoolExpr relatedFailures = relateFailures(enc1, enc2);
    BoolExpr relatedEnvs = relateEnvironments(enc1, enc2);
    BoolExpr relatedPkts = relatePackets(enc1, enc2);
    BoolExpr related = enc1.mkAnd(relatedFailures, relatedEnvs, relatedPkts);
    BoolExpr required = enc1.mkTrue();
    for (GraphEdge ge : graph.getAllRealEdges()) {
        SymbolicDecisions d1 = enc1.getMainSlice().getSymbolicDecisions();
        SymbolicDecisions d2 = enc2.getMainSlice().getSymbolicDecisions();
        BoolExpr dataFwd1 = d1.getDataForwarding().get(ge.getRouter(), ge);
        BoolExpr dataFwd2 = d2.getDataForwarding().get(ge.getRouter(), ge);
        assert dataFwd1 != null;
        assert dataFwd2 != null;
        required = enc1.mkAnd(required, enc1.mkEq(dataFwd1, dataFwd2));
    }
    enc1.add(related);
    enc1.add(enc1.mkNot(required));
    Tuple<VerificationResult, Model> tup = enc1.verify();
    VerificationResult res = tup.getFirst();
    Model model = tup.getSecond();
    SortedSet<String> case1 = null;
    SortedSet<String> case2 = null;
    Flow flow = null;
    CounterExample ce = new CounterExample(model);
    if (!res.isVerified()) {
        case1 = new TreeSet<>();
        case2 = new TreeSet<>();
        flow = ce.buildFlow(enc1.getMainSlice().getSymbolicPacket(), "(none)");
        for (GraphEdge ge : graph.getAllRealEdges()) {
            SymbolicDecisions d1 = enc1.getMainSlice().getSymbolicDecisions();
            SymbolicDecisions d2 = enc2.getMainSlice().getSymbolicDecisions();
            BoolExpr dataFwd1 = d1.getDataForwarding().get(ge.getRouter(), ge);
            BoolExpr dataFwd2 = d2.getDataForwarding().get(ge.getRouter(), ge);
            assert dataFwd1 != null;
            assert dataFwd2 != null;
            boolean b1 = ce.boolVal(dataFwd1);
            boolean b2 = ce.boolVal(dataFwd2);
            if (b1 != b2) {
                if (b1) {
                    String route = ce.buildRoute(enc1.getMainSlice(), ge);
                    String msg = ge + " -- " + route;
                    case1.add(msg);
                }
                if (b2) {
                    String route = ce.buildRoute(enc2.getMainSlice(), ge);
                    String msg = ge + " -- " + route;
                    case2.add(msg);
                }
            }
        }
    }
    // Ensure canonical order
    boolean less = (case1 == null || (case1.first().compareTo(case2.first()) < 0));
    if (less) {
        return new SmtDeterminismAnswerElement(flow, case1, case2);
    } else {
        return new SmtDeterminismAnswerElement(flow, case2, case1);
    }
}

Example 70 with BoolExpr

use of com.microsoft.z3.BoolExpr in project batfish by batfish.

the class PropertyChecker method checkBoundedLength.

/*
   * Compute whether the path length will always be bounded by a constant k
   * for a collection of source routers to any of a number of destination ports.
   */
public AnswerElement checkBoundedLength(HeaderLocationQuestion q, int k) {
    return checkProperty(q, (enc, srcRouters, destPorts) -> {
        ArithExpr bound = enc.mkInt(k);
        PropertyAdder pa = new PropertyAdder(enc.getMainSlice());
        Map<String, ArithExpr> lenVars = pa.instrumentPathLength(destPorts);
        Map<String, BoolExpr> boundVars = new HashMap<>();
        lenVars.forEach((n, ae) -> boundVars.put(n, enc.mkLe(ae, bound)));
        return boundVars;
    }, (vp) -> new SmtOneAnswerElement(vp.getResult()));
}