Examples with HeaderLocationQuestion org.batfish.datamodel.questions.smt.HeaderLocationQuestion used on opensource projects

Example 1 with HeaderLocationQuestion

use of org.batfish.datamodel.questions.smt.HeaderLocationQuestion in project batfish by batfish.

the class PropertyChecker method checkReachability.

/*
   * Check if a collection of routers will be reachable to
   * one or more destinations.
   */
public AnswerElement checkReachability(HeaderLocationQuestion q) {
    return checkProperty(q, (enc, srcRouters, destPorts) -> {
        PropertyAdder pa = new PropertyAdder(enc.getMainSlice());
        return pa.instrumentReachability(destPorts);
    }, (vp) -> {
        if (vp.getResult().isVerified()) {
            return new SmtReachabilityAnswerElement(vp.getResult(), new FlowHistory());
        } else {
            FlowHistory fh;
            CounterExample ce = new CounterExample(vp.getModel());
            String testrigName = _batfish.getTestrigName();
            if (q.getDiffType() != null) {
                fh = ce.buildFlowHistoryDiff(testrigName, vp.getSrcRouters(), vp.getEnc(), vp.getEncDiff(), vp.getProp(), vp.getPropDiff());
            } else {
                Map<String, Boolean> reachVals = vp.getProp().entrySet().stream().collect(Collectors.toMap(Map.Entry::getKey, entry -> ce.isTrue(entry.getValue()) ^ q.getNegate()));
                fh = ce.buildFlowHistory(testrigName, vp.getSrcRouters(), vp.getEnc(), reachVals);
            }
            return new SmtReachabilityAnswerElement(vp.getResult(), fh);
        }
    });
}

Example 2 with HeaderLocationQuestion

use of org.batfish.datamodel.questions.smt.HeaderLocationQuestion in project batfish by batfish.

the class PropertyChecker method checkProperty.

/*
   * General purpose logic for checking a property that holds that
   * handles the various flags and parameters for a query with endpoints
   *
   * q is the question from the user.
   * instrument instruments each router in the graph as needed to check the property.
   * answer takes the result from Z3 and produces the answer for the user.
   *
   */
private AnswerElement checkProperty(HeaderLocationQuestion q, TriFunction<Encoder, Set<String>, Set<GraphEdge>, Map<String, BoolExpr>> instrument, Function<VerifyParam, AnswerElement> answer) {
    long totalTime = System.currentTimeMillis();
    PathRegexes p = new PathRegexes(q);
    Graph graph = new Graph(_batfish);
    Set<GraphEdge> destPorts = findFinalInterfaces(graph, p);
    List<String> sourceRouters = PatternUtils.findMatchingSourceNodes(graph, p);
    if (destPorts.isEmpty()) {
        throw new BatfishException("Set of valid destination interfaces is empty");
    }
    if (sourceRouters.isEmpty()) {
        throw new BatfishException("Set of valid ingress nodes is empty");
    }
    inferDestinationHeaderSpace(graph, destPorts, q);
    Set<GraphEdge> failOptions = failLinkSet(graph, q);
    Tuple<Stream<Supplier<NetworkSlice>>, Long> ecs = findAllNetworkSlices(q, graph, true);
    Stream<Supplier<NetworkSlice>> stream = ecs.getFirst();
    Long timeAbstraction = ecs.getSecond();
    AnswerElement[] answerElement = new AnswerElement[1];
    VerificationResult[] result = new VerificationResult[2];
    List<VerificationStats> ecStats = new ArrayList<>();
    // Checks ECs in parallel, but short circuits when a counterexample is found
    boolean hasCounterExample = stream.anyMatch(lazyEc -> {
        long timeEc = System.currentTimeMillis();
        NetworkSlice slice = lazyEc.get();
        timeEc = System.currentTimeMillis() - timeEc;
        synchronized (_lock) {
            // Make sure the headerspace is correct
            HeaderLocationQuestion question = new HeaderLocationQuestion(q);
            question.setHeaderSpace(slice.getHeaderSpace());
            // Get the EC graph and mapping
            Graph g = slice.getGraph();
            Set<String> srcRouters = mapConcreteToAbstract(slice, sourceRouters);
            long timeEncoding = System.currentTimeMillis();
            Encoder enc = new Encoder(_settings, g, question);
            enc.computeEncoding();
            timeEncoding = System.currentTimeMillis() - timeEncoding;
            // Add environment constraints for base case
            if (question.getDiffType() != null) {
                if (question.getEnvDiff()) {
                    addEnvironmentConstraints(enc, question.getDeltaEnvironmentType());
                }
            } else {
                addEnvironmentConstraints(enc, question.getBaseEnvironmentType());
            }
            Map<String, BoolExpr> prop = instrument.apply(enc, srcRouters, destPorts);
            // If this is a equivalence query, we create a second copy of the network
            Encoder enc2 = null;
            Map<String, BoolExpr> prop2 = null;
            if (question.getDiffType() != null) {
                HeaderLocationQuestion q2 = new HeaderLocationQuestion(question);
                q2.setFailures(0);
                long timeDiffEncoding = System.currentTimeMillis();
                enc2 = new Encoder(enc, g, q2);
                enc2.computeEncoding();
                timeDiffEncoding = System.currentTimeMillis() - timeDiffEncoding;
                timeEncoding += timeDiffEncoding;
            }
            if (question.getDiffType() != null) {
                assert (enc2 != null);
                // create a map for enc2 to lookup a related environment variable from enc
                Table2<GraphEdge, EdgeType, SymbolicRoute> relatedEnv = new Table2<>();
                enc2.getMainSlice().getLogicalGraph().getEnvironmentVars().forEach((lge, r) -> relatedEnv.put(lge.getEdge(), lge.getEdgeType(), r));
                BoolExpr related = enc.mkTrue();
                addEnvironmentConstraints(enc2, question.getBaseEnvironmentType());
                if (!question.getEnvDiff()) {
                    related = relateEnvironments(enc, enc2);
                }
                prop2 = instrument.apply(enc2, srcRouters, destPorts);
                // Add diff constraints
                BoolExpr required = enc.mkTrue();
                for (String source : srcRouters) {
                    BoolExpr sourceProp1 = prop.get(source);
                    BoolExpr sourceProp2 = prop2.get(source);
                    BoolExpr val;
                    switch(q.getDiffType()) {
                        case INCREASED:
                            val = enc.mkImplies(sourceProp1, sourceProp2);
                            break;
                        case REDUCED:
                            val = enc.mkImplies(sourceProp2, sourceProp1);
                            break;
                        case ANY:
                            val = enc.mkEq(sourceProp1, sourceProp2);
                            break;
                        default:
                            throw new BatfishException("Missing case: " + q.getDiffType());
                    }
                    required = enc.mkAnd(required, val);
                }
                related = enc.mkAnd(related, relatePackets(enc, enc2));
                enc.add(related);
                enc.add(enc.mkNot(required));
            } else {
                // Not a differential query; just a query on a single version of the network.
                BoolExpr allProp = enc.mkTrue();
                for (String router : srcRouters) {
                    BoolExpr r = prop.get(router);
                    if (q.getNegate()) {
                        r = enc.mkNot(r);
                    }
                    allProp = enc.mkAnd(allProp, r);
                }
                enc.add(enc.mkNot(allProp));
            }
            addFailureConstraints(enc, destPorts, failOptions);
            Tuple<VerificationResult, Model> tup = enc.verify();
            VerificationResult res = tup.getFirst();
            Model model = tup.getSecond();
            if (q.getBenchmark()) {
                VerificationStats stats = res.getStats();
                stats.setAvgComputeEcTime(timeEc);
                stats.setMaxComputeEcTime(timeEc);
                stats.setMinComputeEcTime(timeEc);
                stats.setAvgEncodingTime(timeEncoding);
                stats.setMaxEncodingTime(timeEncoding);
                stats.setMinEncodingTime(timeEncoding);
                stats.setTimeCreateBdds((double) timeAbstraction);
                synchronized (_lock) {
                    ecStats.add(stats);
                }
            }
            if (!res.isVerified()) {
                VerifyParam vp = new VerifyParam(res, model, srcRouters, enc, enc2, prop, prop2);
                AnswerElement ae = answer.apply(vp);
                synchronized (_lock) {
                    answerElement[0] = ae;
                    result[0] = res;
                }
                return true;
            }
            synchronized (_lock) {
                result[1] = res;
            }
            return false;
        }
    });
    totalTime = (System.currentTimeMillis() - totalTime);
    VerificationResult res;
    AnswerElement ae;
    if (hasCounterExample) {
        res = result[0];
        ae = answerElement[0];
    } else {
        res = result[1];
        VerifyParam vp = new VerifyParam(res, null, null, null, null, null, null);
        ae = answer.apply(vp);
    }
    if (q.getBenchmark()) {
        VerificationStats stats = VerificationStats.combineAll(ecStats, totalTime);
        res.setStats(stats);
    }
    return ae;
}