Examples with SmtManyAnswerElement org.batfish.symbolic.answers.SmtManyAnswerElement used on opensource projects

Example 1 with SmtManyAnswerElement

use of org.batfish.symbolic.answers.SmtManyAnswerElement in project batfish by batfish.

the class PropertyChecker method checkLocalEquivalence.

/*
   * Computes whether or not two routers are equivalent.
   * To be equivalent, each router must have identical intefaces.
   *
   * We then relate the environments on each interface for each router
   * so that they are required to be equal.
   *
   * We finally check that their forwarding decisions and exported messages
   * will be equal given their equal inputs.
   */
public AnswerElement checkLocalEquivalence(Pattern n, boolean strict, boolean fullModel) {
    Graph graph = new Graph(_batfish);
    List<String> routers = PatternUtils.findMatchingNodes(graph, n, Pattern.compile(""));
    HeaderQuestion q = new HeaderQuestion();
    q.setFullModel(fullModel);
    q.setFailures(0);
    q.setBaseEnvironmentType(EnvironmentType.ANY);
    Collections.sort(routers);
    SortedMap<String, VerificationResult> result = new TreeMap<>();
    int len = routers.size();
    if (len <= 1) {
        return new SmtManyAnswerElement(new TreeMap<>());
    }
    for (int i = 0; i < len - 1; i++) {
        String r1 = routers.get(i);
        String r2 = routers.get(i + 1);
        // TODO: reorder to encode after checking if we can compare them
        // Create transfer function for router 1
        Set<String> toModel1 = new TreeSet<>();
        toModel1.add(r1);
        Graph g1 = new Graph(_batfish, null, toModel1);
        Encoder e1 = new Encoder(_settings, g1, q);
        e1.computeEncoding();
        Context ctx = e1.getCtx();
        // Create transfer function for router 2
        Set<String> toModel2 = new TreeSet<>();
        toModel2.add(r2);
        Graph g2 = new Graph(_batfish, null, toModel2);
        Encoder e2 = new Encoder(e1, g2);
        e2.computeEncoding();
        EncoderSlice slice1 = e1.getMainSlice();
        EncoderSlice slice2 = e2.getMainSlice();
        // Ensure that the two routers have the same interfaces for comparison
        Pattern p = Pattern.compile(".*");
        Pattern neg = Pattern.compile("");
        List<GraphEdge> edges1 = PatternUtils.findMatchingEdges(g1, p, neg, p, neg);
        List<GraphEdge> edges2 = PatternUtils.findMatchingEdges(g2, p, neg, p, neg);
        Set<String> ifaces1 = interfaces(edges1);
        Set<String> ifaces2 = interfaces(edges2);
        if (!(ifaces1.containsAll(ifaces2) && ifaces2.containsAll(ifaces1))) {
            String msg = String.format("Routers %s and %s have different interfaces", r1, r2);
            System.out.println(msg);
            return new SmtManyAnswerElement(new TreeMap<>());
        }
        // TODO: check running same protocols?
        Map<String, Map<Protocol, Map<String, EnumMap<EdgeType, LogicalEdge>>>> lgeMap2 = logicalEdgeMap(slice2);
        BoolExpr equalEnvs = ctx.mkBool(true);
        BoolExpr equalOutputs = ctx.mkBool(true);
        BoolExpr equalIncomingAcls = ctx.mkBool(true);
        Configuration conf1 = g1.getConfigurations().get(r1);
        Configuration conf2 = g2.getConfigurations().get(r2);
        // Set environments equal
        Set<String> communities = new HashSet<>();
        Set<SymbolicRoute> envRecords = new HashSet<>();
        for (Protocol proto1 : slice1.getProtocols().get(r1)) {
            for (ArrayList<LogicalEdge> es : slice1.getLogicalGraph().getLogicalEdges().get(r1).get(proto1)) {
                for (LogicalEdge lge1 : es) {
                    String ifaceName = lge1.getEdge().getStart().getName();
                    LogicalEdge lge2 = lgeMap2.get(r2).get(proto1).get(ifaceName).get(lge1.getEdgeType());
                    if (lge1.getEdgeType() == EdgeType.IMPORT) {
                        SymbolicRoute vars1 = slice1.getLogicalGraph().getEnvironmentVars().get(lge1);
                        SymbolicRoute vars2 = slice2.getLogicalGraph().getEnvironmentVars().get(lge2);
                        BoolExpr aclIn1 = slice1.getIncomingAcls().get(lge1.getEdge());
                        BoolExpr aclIn2 = slice2.getIncomingAcls().get(lge2.getEdge());
                        if (aclIn1 == null) {
                            aclIn1 = ctx.mkBool(true);
                        }
                        if (aclIn2 == null) {
                            aclIn2 = ctx.mkBool(true);
                        }
                        equalIncomingAcls = ctx.mkAnd(equalIncomingAcls, ctx.mkEq(aclIn1, aclIn2));
                        boolean hasEnv1 = (vars1 != null);
                        boolean hasEnv2 = (vars2 != null);
                        if (hasEnv1 && hasEnv2) {
                            BoolExpr samePermitted = ctx.mkEq(vars1.getPermitted(), vars2.getPermitted());
                            // Set communities equal
                            BoolExpr equalComms = e1.mkTrue();
                            for (Map.Entry<CommunityVar, BoolExpr> entry : vars1.getCommunities().entrySet()) {
                                CommunityVar cvar = entry.getKey();
                                BoolExpr ce1 = entry.getValue();
                                BoolExpr ce2 = vars2.getCommunities().get(cvar);
                                if (ce2 != null) {
                                    equalComms = e1.mkAnd(equalComms, e1.mkEq(ce1, ce2));
                                }
                            }
                            // Set communities belonging to one but not the other
                            // off, but give a warning of the difference
                            BoolExpr unsetComms = e1.mkTrue();
                            for (Map.Entry<CommunityVar, BoolExpr> entry : vars1.getCommunities().entrySet()) {
                                CommunityVar cvar = entry.getKey();
                                BoolExpr ce1 = entry.getValue();
                                BoolExpr ce2 = vars2.getCommunities().get(cvar);
                                if (ce2 == null) {
                                    if (!communities.contains(cvar.getValue())) {
                                        communities.add(cvar.getValue());
                                    /* String msg =
                       String.format(
                           "Warning: community %s found for router %s but not %s.",
                           cvar.getValue(), conf1.getEnvName(), conf2.getEnvName());
                      System.out.println(msg); */
                                    }
                                    unsetComms = e1.mkAnd(unsetComms, e1.mkNot(ce1));
                                }
                            }
                            // Do the same thing for communities missing from the other side
                            for (Map.Entry<CommunityVar, BoolExpr> entry : vars2.getCommunities().entrySet()) {
                                CommunityVar cvar = entry.getKey();
                                BoolExpr ce2 = entry.getValue();
                                BoolExpr ce1 = vars1.getCommunities().get(cvar);
                                if (ce1 == null) {
                                    if (!communities.contains(cvar.getValue())) {
                                        communities.add(cvar.getValue());
                                    /* String msg =
                       String.format(
                           "Warning: community %s found for router %s but not %s.",
                           cvar.getValue(), conf2.getEnvName(), conf1.getEnvName());
                      System.out.println(msg); */
                                    }
                                    unsetComms = e1.mkAnd(unsetComms, e1.mkNot(ce2));
                                }
                            }
                            envRecords.add(vars1);
                            BoolExpr equalVars = slice1.equal(conf1, proto1, vars1, vars2, lge1, true);
                            equalEnvs = ctx.mkAnd(equalEnvs, unsetComms, samePermitted, equalVars, equalComms);
                        } else if (hasEnv1 || hasEnv2) {
                            System.out.println("Edge1: " + lge1);
                            System.out.println("Edge2: " + lge2);
                            throw new BatfishException("one had environment");
                        }
                    } else {
                        SymbolicRoute out1 = lge1.getSymbolicRecord();
                        SymbolicRoute out2 = lge2.getSymbolicRecord();
                        equalOutputs = ctx.mkAnd(equalOutputs, slice1.equal(conf1, proto1, out1, out2, lge1, false));
                    }
                }
            }
        }
        // check the stronger version of local equivalence
        if (strict) {
            for (SymbolicRoute env1 : envRecords) {
                for (SymbolicRoute env2 : envRecords) {
                    if (!env1.equals(env2)) {
                        BoolExpr c = e2.mkImplies(env1.getPermitted(), e2.mkNot(env2.getPermitted()));
                        e2.add(c);
                    }
                }
            }
        }
        // TODO: check both have same environment vars (e.g., screw up configuring peer connection)
        // Create assumptions
        BoolExpr validDest;
        validDest = ignoredDestinations(ctx, slice1, r1, conf1);
        validDest = ctx.mkAnd(validDest, ignoredDestinations(ctx, slice2, r2, conf2));
        SymbolicPacket p1 = slice1.getSymbolicPacket();
        SymbolicPacket p2 = slice2.getSymbolicPacket();
        BoolExpr equalPackets = p1.mkEqual(p2);
        BoolExpr assumptions = ctx.mkAnd(equalEnvs, equalPackets, validDest);
        // Create the requirements
        // Best choices should be the same
        BoolExpr required;
        if (strict) {
            SymbolicRoute best1 = e1.getMainSlice().getSymbolicDecisions().getBestNeighbor().get(conf1.getName());
            SymbolicRoute best2 = e2.getMainSlice().getSymbolicDecisions().getBestNeighbor().get(conf2.getName());
            // Just pick some protocol for defaults, shouldn't matter for best choice
            required = equal(e2, conf2, best1, best2);
        } else {
            // Forwarding decisions should be the sames
            Map<String, GraphEdge> geMap2 = interfaceMap(edges2);
            BoolExpr sameForwarding = ctx.mkBool(true);
            for (GraphEdge ge1 : edges1) {
                GraphEdge ge2 = geMap2.get(ge1.getStart().getName());
                BoolExpr dataFwd1 = slice1.getSymbolicDecisions().getDataForwarding().get(r1, ge1);
                BoolExpr dataFwd2 = slice2.getSymbolicDecisions().getDataForwarding().get(r2, ge2);
                assert (dataFwd1 != null);
                assert (dataFwd2 != null);
                sameForwarding = ctx.mkAnd(sameForwarding, ctx.mkEq(dataFwd1, dataFwd2));
            }
            // equalOutputs, equalIncomingAcls);
            required = ctx.mkAnd(sameForwarding);
        }
        e2.add(assumptions);
        e2.add(ctx.mkNot(required));
        VerificationResult res = e2.verify().getFirst();
        String name = r1 + "<-->" + r2;
        result.put(name, res);
    }
    return new SmtManyAnswerElement(result);
}