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

Example 41 with BoolExpr

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

the class Encoder method environmentBlockingClause.

/*
   * Generate a blocking clause for the encoding that says that one
   * of the environments that was true before must now be false.
   */
private BoolExpr environmentBlockingClause(Model m) {
    BoolExpr acc1 = mkFalse();
    BoolExpr acc2 = mkTrue();
    // Disable an environment edge if possible
    Map<LogicalEdge, SymbolicRoute> map = getMainSlice().getLogicalGraph().getEnvironmentVars();
    for (Map.Entry<LogicalEdge, SymbolicRoute> entry : map.entrySet()) {
        SymbolicRoute record = entry.getValue();
        BoolExpr per = record.getPermitted();
        Expr x = m.evaluate(per, false);
        if (x.toString().equals("true")) {
            acc1 = mkOr(acc1, mkNot(per));
        } else {
            acc2 = mkAnd(acc2, mkNot(per));
        }
    }
    // Disable a community value if possible
    for (Map.Entry<LogicalEdge, SymbolicRoute> entry : map.entrySet()) {
        SymbolicRoute record = entry.getValue();
        for (Map.Entry<CommunityVar, BoolExpr> centry : record.getCommunities().entrySet()) {
            BoolExpr comm = centry.getValue();
            Expr x = m.evaluate(comm, false);
            if (x.toString().equals("true")) {
                acc1 = mkOr(acc1, mkNot(comm));
            } else {
                acc2 = mkAnd(acc2, mkNot(comm));
            }
        }
    }
    return mkAnd(acc1, acc2);
}

Example 42 with BoolExpr

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

the class Encoder method verify.

/**
 * Checks that a property is always true by seeing if the encoding is unsatisfiable. mkIf the
 * model is satisfiable, then there is a counter example to the property.
 *
 * @return A VerificationResult indicating the status of the check.
 */
public Tuple<VerificationResult, Model> verify() {
    EncoderSlice mainSlice = _slices.get(MAIN_SLICE_NAME);
    int numVariables = _allVariables.size();
    int numConstraints = _solver.getAssertions().length;
    int numNodes = mainSlice.getGraph().getConfigurations().size();
    int numEdges = 0;
    for (Map.Entry<String, Set<String>> e : mainSlice.getGraph().getNeighbors().entrySet()) {
        numEdges += e.getValue().size();
    }
    long start = System.currentTimeMillis();
    Status status = _solver.check();
    long time = System.currentTimeMillis() - start;
    VerificationStats stats = null;
    if (_question.getBenchmark()) {
        stats = new VerificationStats();
        stats.setAvgNumNodes(numNodes);
        stats.setMaxNumNodes(numNodes);
        stats.setMinNumNodes(numNodes);
        stats.setAvgNumEdges(numEdges);
        stats.setMaxNumEdges(numEdges);
        stats.setMinNumEdges(numEdges);
        stats.setAvgNumVariables(numVariables);
        stats.setMaxNumVariables(numVariables);
        stats.setMinNumVariables(numVariables);
        stats.setAvgNumConstraints(numConstraints);
        stats.setMaxNumConstraints(numConstraints);
        stats.setMinNumConstraints(numConstraints);
        stats.setAvgSolverTime(time);
        stats.setMaxSolverTime(time);
        stats.setMinSolverTime(time);
    }
    if (status == Status.UNSATISFIABLE) {
        VerificationResult res = new VerificationResult(true, null, null, null, null, null, stats);
        return new Tuple<>(res, null);
    } else if (status == Status.UNKNOWN) {
        throw new BatfishException("ERROR: satisfiability unknown");
    } else {
        VerificationResult result;
        Model m;
        while (true) {
            m = _solver.getModel();
            SortedMap<String, String> model = new TreeMap<>();
            SortedMap<String, String> packetModel = new TreeMap<>();
            SortedSet<String> fwdModel = new TreeSet<>();
            SortedMap<String, SortedMap<String, String>> envModel = new TreeMap<>();
            SortedSet<String> failures = new TreeSet<>();
            buildCounterExample(this, m, model, packetModel, fwdModel, envModel, failures);
            if (_previousEncoder != null) {
                buildCounterExample(_previousEncoder, m, model, packetModel, fwdModel, envModel, failures);
            }
            result = new VerificationResult(false, model, packetModel, envModel, fwdModel, failures, stats);
            if (!_question.getMinimize()) {
                break;
            }
            BoolExpr blocking = environmentBlockingClause(m);
            add(blocking);
            Status s = _solver.check();
            if (s == Status.UNSATISFIABLE) {
                break;
            }
            if (s == Status.UNKNOWN) {
                throw new BatfishException("ERROR: satisfiability unknown");
            }
        }
        return new Tuple<>(result, m);
    }
}

Example 43 with BoolExpr

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

the class EncoderSlice method initForwardingAcross.

/*
   * Initialize boolean expressions to represent that traffic sent along
   * and edge will reach the other side of the edge.
   */
private void initForwardingAcross() {
    _symbolicDecisions.getDataForwarding().forEach((router, edge, var) -> {
        BoolExpr inAcl;
        if (edge.getEnd() == null) {
            inAcl = mkTrue();
        } else {
            GraphEdge ge = getGraph().getOtherEnd().get(edge);
            inAcl = _inboundAcls.get(ge);
            if (inAcl == null) {
                inAcl = mkTrue();
            }
        }
        _forwardsAcross.put(router, edge, mkAnd(var, inAcl));
    });
}

Example 44 with BoolExpr

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

the class EncoderSlice method equalCommunities.

private BoolExpr equalCommunities(SymbolicRoute best, SymbolicRoute vars) {
    BoolExpr acc = mkTrue();
    for (Map.Entry<CommunityVar, BoolExpr> entry : best.getCommunities().entrySet()) {
        CommunityVar cvar = entry.getKey();
        BoolExpr var = entry.getValue();
        BoolExpr other = vars.getCommunities().get(cvar);
        if (other == null) {
            acc = mkAnd(acc, mkNot(var));
        } else {
            acc = mkAnd(acc, mkEq(var, other));
        }
    }
    return acc;
}

Example 45 with BoolExpr

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

the class EncoderSlice method computeIpProtocols.

/*
   * Convert a set of ip protocols to a boolean expression on the symbolic packet
   */
private BoolExpr computeIpProtocols(Set<IpProtocol> ipProtos) {
    BoolExpr acc = mkFalse();
    for (IpProtocol proto : ipProtos) {
        ArithExpr protoNum = mkInt(proto.number());
        acc = mkOr(acc, mkEq(protoNum, _symbolicPacket.getIpProtocol()));
    }
    return (BoolExpr) acc.simplify();
}