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

Example 6 with BitVecExpr

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

the class Z3ContextJob method getSolverInput.

protected BoolExpr getSolverInput(Expr answer, NodProgram program, boolean negate) {
    BoolExpr solverInput;
    if (answer.getArgs().length > 0) {
        Map<String, BitVecExpr> variablesAsConsts = program.getNodContext().getVariablesAsConsts();
        List<BitVecExpr> reversedVars = Lists.reverse(program.getNodContext().getVariableNames().stream().filter(name -> !TransformationHeaderField.transformationHeaderFieldNames.contains(name)).map(variablesAsConsts::get).collect(Collectors.toList()));
        Expr substitutedAnswer = answer.substituteVars(reversedVars.toArray(new Expr[] {}));
        solverInput = (BoolExpr) substitutedAnswer;
    } else {
        solverInput = (BoolExpr) answer;
    }
    if (negate) {
        solverInput = program.getNodContext().getContext().mkNot(solverInput);
    }
    return solverInput;
}

Example 7 with BitVecExpr

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

the class BitVecExprTransformer method visitVarIntExpr.

@Override
public BitVecExpr visitVarIntExpr(VarIntExpr varIntExpr) {
    String headerField = varIntExpr.getField().getName();
    BitVecExpr ret = _nodContext.getVariables().get(headerField);
    if (ret == null) {
        throw new BatfishException("nodContext missing mapping for variable: '" + headerField + "'");
    }
    return ret;
}

Example 8 with BitVecExpr

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

the class EncoderSlice method computeWildcardMatch.

/*
   * Convert a set of wildcards and a packet field to a symbolic boolean expression
   */
private BoolExpr computeWildcardMatch(Set<IpWildcard> wcs, BitVecExpr field) {
    BoolExpr acc = mkFalse();
    for (IpWildcard wc : wcs) {
        ipWildCardBound(field, wc);
        acc = mkOr(acc, ipWildCardBound(field, wc));
    }
    return (BoolExpr) acc.simplify();
}

Example 9 with BitVecExpr

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

the class EncoderSlice method addControlForwardingConstraints.

/*
   * Constraints that define control-plane forwarding.
   * If there is some valid import, then control plane forwarding
   * will occur out an interface when this is the best choice.
   * Otherwise, it will not occur.
   */
private void addControlForwardingConstraints() {
    for (Entry<String, Configuration> entry : getGraph().getConfigurations().entrySet()) {
        String router = entry.getKey();
        Configuration conf = entry.getValue();
        boolean someEdge = false;
        SymbolicRoute best = _symbolicDecisions.getBestNeighbor().get(router);
        Map<GraphEdge, BoolExpr> cfExprs = new HashMap<>();
        Set<GraphEdge> constrained = new HashSet<>();
        for (Protocol proto : getProtocols().get(router)) {
            for (LogicalEdge e : collectAllImportLogicalEdges(router, conf, proto)) {
                someEdge = true;
                constrained.add(e.getEdge());
                SymbolicRoute vars = correctVars(e);
                BoolExpr choice = _symbolicDecisions.getChoiceVariables().get(router, proto, e);
                BoolExpr isBest = mkAnd(choice, equal(conf, proto, best, vars, e, false));
                GraphEdge ge = e.getEdge();
                // Connected routes should only forward if not absorbed by interface
                GraphEdge other = getGraph().getOtherEnd().get(ge);
                BoolExpr connectedWillSend;
                if (other == null || getGraph().isHost(ge.getPeer())) {
                    Ip ip = ge.getStart().getAddress().getIp();
                    BitVecExpr val = getCtx().mkBV(ip.asLong(), 32);
                    connectedWillSend = mkNot(mkEq(_symbolicPacket.getDstIp(), val));
                } else {
                    Ip ip = other.getStart().getAddress().getIp();
                    BitVecExpr val = getCtx().mkBV(ip.asLong(), 32);
                    connectedWillSend = mkEq(_symbolicPacket.getDstIp(), val);
                }
                BoolExpr canSend = (proto.isConnected() ? connectedWillSend : mkTrue());
                BoolExpr sends = mkAnd(canSend, isBest);
                BoolExpr cForward = _symbolicDecisions.getControlForwarding().get(router, ge);
                assert (cForward != null);
                add(mkImplies(sends, cForward));
                // record the negation as well
                cfExprs.merge(ge, sends, (a, b) -> mkOr(a, b));
            }
        }
        // For edges that are never used, we constraint them to not be forwarded out of
        for (GraphEdge ge : getGraph().getEdgeMap().get(router)) {
            if (!constrained.contains(ge)) {
                BoolExpr cForward = _symbolicDecisions.getControlForwarding().get(router, ge);
                assert (cForward != null);
                add(mkNot(cForward));
            }
        }
        // Handle the case that the router has no protocol running
        if (!someEdge) {
            for (GraphEdge ge : getGraph().getEdgeMap().get(router)) {
                BoolExpr cForward = _symbolicDecisions.getControlForwarding().get(router, ge);
                assert (cForward != null);
                add(mkNot(cForward));
            }
        } else {
            // If no best route, then no forwarding
            Map<Protocol, List<ArrayList<LogicalEdge>>> map = _logicalGraph.getLogicalEdges().get(router);
            Set<GraphEdge> seen = new HashSet<>();
            for (List<ArrayList<LogicalEdge>> eList : map.values()) {
                for (ArrayList<LogicalEdge> edges : eList) {
                    for (LogicalEdge le : edges) {
                        GraphEdge ge = le.getEdge();
                        if (seen.contains(ge)) {
                            continue;
                        }
                        seen.add(ge);
                        BoolExpr expr = cfExprs.get(ge);
                        BoolExpr cForward = _symbolicDecisions.getControlForwarding().get(router, ge);
                        assert (cForward != null);
                        if (expr != null) {
                            add(mkImplies(mkNot(expr), mkNot(cForward)));
                        } else {
                            add(mkNot(cForward));
                        }
                    }
                }
            }
        }
    }
}

Example 10 with BitVecExpr

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

the class EncoderSlice method greaterOrEqual.

/*
   * Check if a (best) symbolic record is better than another
   * symbolic record (vars). This is done using a recursive lexicographic
   * encoding. The encoding is as follows:
   *
   * (best.length > vars.length) or
   * (best.length = vars.length) and (
   *    (best.adminDist < vars.adminDist) or
   *    (best.adminDist = vars.adminDist) and (
   *     ...
   *    )
   * )
   *
   * This recursive encoding introduces a new variable for each subexpressions,
   * which ends up being much more efficient than expanding out options.
   */
private BoolExpr greaterOrEqual(Configuration conf, Protocol proto, SymbolicRoute best, SymbolicRoute vars, @Nullable LogicalEdge e) {
    ArithExpr defaultLocal = mkInt(defaultLocalPref());
    ArithExpr defaultAdmin = defaultAdminDistance(conf, proto, vars);
    ArithExpr defaultMet = mkInt(defaultMetric());
    ArithExpr defaultMed = mkInt(defaultMed(proto));
    ArithExpr defaultLen = mkInt(defaultLength());
    ArithExpr defaultIgp = mkInt(defaultIgpMetric());
    ArithExpr defaultId = mkInt(0);
    BitVecExpr defaultOspfType = defaultOspfType();
    BoolExpr betterLen = geBetterHelper(best.getPrefixLength(), vars.getPrefixLength(), defaultLen, false);
    BoolExpr equalLen = geEqualHelper(best.getPrefixLength(), vars.getPrefixLength(), defaultLen);
    BoolExpr betterAd = geBetterHelper(best.getAdminDist(), vars.getAdminDist(), defaultAdmin, true);
    BoolExpr equalAd = geEqualHelper(best.getAdminDist(), vars.getAdminDist(), defaultAdmin);
    BoolExpr betterLp = geBetterHelper(best.getLocalPref(), vars.getLocalPref(), defaultLocal, false);
    BoolExpr equalLp = geEqualHelper(best.getLocalPref(), vars.getLocalPref(), defaultLocal);
    BoolExpr betterMet = geBetterHelper(best.getMetric(), vars.getMetric(), defaultMet, true);
    BoolExpr equalMet = geEqualHelper(best.getMetric(), vars.getMetric(), defaultMet);
    BoolExpr betterMed = geBetterHelper(best.getMed(), vars.getMed(), defaultMed, true);
    BoolExpr equalMed = geEqualHelper(best.getMed(), vars.getMed(), defaultMed);
    BitVecExpr bestType = (best.getOspfType() == null ? null : best.getOspfType().getBitVec());
    BitVecExpr varsType = (vars.getOspfType() == null ? null : vars.getOspfType().getBitVec());
    BoolExpr betterOspfType = geBetterHelper(bestType, varsType, defaultOspfType, true);
    BoolExpr equalOspfType = geEqualHelper(bestType, varsType, defaultOspfType);
    BoolExpr betterInternal = geBetterHelper(best.getBgpInternal(), vars.getBgpInternal(), mkFalse(), true);
    BoolExpr equalInternal = geEqualHelper(best.getBgpInternal(), vars.getBgpInternal(), mkFalse());
    BoolExpr betterIgpMet = geBetterHelper(best.getIgpMetric(), vars.getIgpMetric(), defaultIgp, true);
    BoolExpr equalIgpMet = geEqualHelper(best.getIgpMetric(), vars.getIgpMetric(), defaultIgp);
    BoolExpr tiebreak;
    if (vars.getRouterId() != null) {
        tiebreak = mkLe(best.getRouterId(), vars.getRouterId());
    } else if (best.getRouterId() != null) {
        if (e == null) {
            tiebreak = mkLe(best.getRouterId(), defaultId);
        } else {
            long peerId = getGraph().findRouterId(e.getEdge(), proto);
            tiebreak = mkLe(best.getRouterId(), mkInt(peerId));
        }
    } else {
        tiebreak = mkTrue();
    }
    BoolExpr b = mkAnd(equalOspfType, tiebreak);
    BoolExpr b1 = mkOr(betterOspfType, b);
    BoolExpr b2 = mkAnd(equalIgpMet, b1);
    BoolExpr b3 = mkOr(betterIgpMet, b2);
    BoolExpr b4 = mkAnd(equalInternal, b3);
    BoolExpr b5 = mkOr(betterInternal, b4);
    BoolExpr b6 = mkAnd(equalMed, b5);
    BoolExpr b7 = mkOr(betterMed, b6);
    BoolExpr b8 = mkAnd(equalMet, b7);
    BoolExpr b9 = mkOr(betterMet, b8);
    BoolExpr b10 = mkAnd(equalLp, b9);
    BoolExpr b11 = mkOr(betterLp, b10);
    BoolExpr b12 = mkAnd(equalAd, b11);
    BoolExpr b13 = mkOr(betterAd, b12);
    BoolExpr b14 = mkAnd(equalLen, b13);
    return mkOr(betterLen, b14);
}