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

Example 61 with Context

use of com.microsoft.z3.Context 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 62 with Context

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

the class PropertyChecker method ignoredDestinations.

/*
   * Creates a boolean variable representing destinations we don't want
   * to consider due to local differences.
   */
private BoolExpr ignoredDestinations(Context ctx, EncoderSlice e1, String r1, Configuration conf1) {
    BoolExpr validDest = ctx.mkBool(true);
    for (Protocol proto1 : e1.getProtocols().get(r1)) {
        Set<Prefix> prefixes = Graph.getOriginatedNetworks(conf1, proto1);
        BoolExpr dest = e1.relevantOrigination(prefixes);
        validDest = ctx.mkAnd(validDest, ctx.mkNot(dest));
    }
    return validDest;
}

Example 63 with Context

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

the class NodFirstUnsatJob method call.

@Override
public NodFirstUnsatResult<KeyT, ResultT> call() {
    long startTime = System.currentTimeMillis();
    try (Context ctx = new Context()) {
        ReachabilityProgram baseProgram = _query.synthesizeBaseProgram(_synthesizer);
        ReachabilityProgram queryProgram = _query.getReachabilityProgram(_synthesizer.getInput());
        NodProgram program = new NodProgram(ctx, baseProgram, queryProgram);
        Fixedpoint fix = mkFixedpoint(program, false);
        KeyT key = _query.getKey();
        for (int queryNum = 0; queryNum < program.getQueries().size(); queryNum++) {
            BoolExpr query = program.getQueries().get(queryNum);
            Status status = fix.query(query);
            switch(status) {
                case SATISFIABLE:
                    break;
                case UNKNOWN:
                    return new NodFirstUnsatResult<>(startTime, _logger.getHistory(), new BatfishException("Query satisfiability unknown"));
                case UNSATISFIABLE:
                    return new NodFirstUnsatResult<>(key, queryNum, _query.getResultsByQueryIndex().get(queryNum), _logger.getHistory(), startTime);
                default:
                    return new NodFirstUnsatResult<>(startTime, _logger.getHistory(), new BatfishException("invalid status"));
            }
        }
        return new NodFirstUnsatResult<>(key, null, null, _logger.getHistory(), startTime);
    } catch (Z3Exception e) {
        return new NodFirstUnsatResult<>(startTime, _logger.getHistory(), new BatfishException("Error running NoD on concatenated data plane", e));
    }
}

Example 64 with Context

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

the class NodJob method computeSmtInput.

@Override
protected SmtInput computeSmtInput(long startTime, Context ctx) {
    NodProgram program = getNodProgram(ctx);
    BoolExpr expr = computeSmtConstraintsViaNod(program, _querySynthesizer.getNegate());
    Map<String, BitVecExpr> variablesAsConsts = program.getNodContext().getVariablesAsConsts();
    return new SmtInput(expr, variablesAsConsts);
}

Example 65 with Context

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

the class NodSatJob method call.

@Override
public NodSatResult<KeyT> call() {
    Map<KeyT, Boolean> results = new LinkedHashMap<>();
    long startTime = System.currentTimeMillis();
    try (Context ctx = new Context()) {
        ReachabilityProgram baseProgram = _query.synthesizeBaseProgram(_synthesizer);
        ReachabilityProgram queryProgram = _query.getReachabilityProgram(_synthesizer.getInput());
        NodProgram program = new NodProgram(ctx, baseProgram, queryProgram);
        Fixedpoint fix = mkFixedpoint(program, false);
        for (int queryNum = 0; queryNum < program.getQueries().size(); queryNum++) {
            BoolExpr query = program.getQueries().get(queryNum);
            KeyT key = _query.getKeys().get(queryNum);
            Status status = fix.query(query);
            switch(status) {
                case SATISFIABLE:
                    results.put(key, true);
                    break;
                case UNKNOWN:
                    return new NodSatResult<>(startTime, _logger.getHistory(), new BatfishException("Query satisfiability unknown"));
                case UNSATISFIABLE:
                    results.put(key, false);
                    break;
                default:
                    return new NodSatResult<>(startTime, _logger.getHistory(), new BatfishException("invalid status"));
            }
        }
        return new NodSatResult<>(results, _logger.getHistory(), startTime);
    } catch (Z3Exception e) {
        return new NodSatResult<>(startTime, _logger.getHistory(), new BatfishException("Error running NoD on concatenated data plane", e));
    }
}