verigraph/service/src/mcnet/netobjs/AclFirewall.java

   1 /*******************************************************************************
   2  * Copyright (c) 2017 Politecnico di Torino and others.
   3  *
   4  * All rights reserved. This program and the accompanying materials
   5  * are made available under the terms of the Apache License, Version 2.0
   6  * which accompanies this distribution, and is available at
   7  * http://www.apache.org/licenses/LICENSE-2.0
   8  *******************************************************************************/
   9
  10 package mcnet.netobjs;
  11
  12 import java.util.ArrayList;
  13 import java.util.List;
  14
  15 import com.microsoft.z3.BoolExpr;
  16 import com.microsoft.z3.Context;
  17 import com.microsoft.z3.DatatypeExpr;
  18 import com.microsoft.z3.Expr;
  19 import com.microsoft.z3.FuncDecl;
  20 import com.microsoft.z3.IntExpr;
  21 import com.microsoft.z3.Solver;
  22 import com.microsoft.z3.Sort;
  23
  24 import mcnet.components.NetContext;
  25 import mcnet.components.Network;
  26 import mcnet.components.NetworkObject;
  27 import mcnet.components.Tuple;
  28
  29 /** Represents a Firewall with the associated Access Control List
  30  *
  31  */
  32 public class AclFirewall extends NetworkObject{
  33
  34         List<BoolExpr> constraints;
  35         Context ctx;
  36         DatatypeExpr fw;
  37         ArrayList<Tuple<DatatypeExpr,DatatypeExpr>> acls;
  38         Network net;
  39         NetContext nctx;
  40         FuncDecl acl_func;
  41
  42         public AclFirewall(Context ctx, Object[]... args) {
  43                 super(ctx, args);
  44         }
  45
  46         @Override
  47         protected void init(Context ctx, Object[]... args) {
  48                 this.ctx = ctx;
  49                 isEndHost=false;
  50                 constraints = new ArrayList<BoolExpr>();
  51                 acls = new ArrayList<Tuple<DatatypeExpr,DatatypeExpr>>();
  52                 z3Node = ((NetworkObject)args[0][0]).getZ3Node();
  53         fw = z3Node;
  54             net = (Network)args[0][1];
  55             nctx = (NetContext)args[0][2];
  56             net.saneSend(this);
  57                 firewallSendRules();
  58         }
  59
  60         /**
  61          * Wrap add acls
  62          * @param policy
  63          */
  64         public void setPolicy(ArrayList<Tuple<DatatypeExpr, DatatypeExpr>> policy){
  65                 addAcls(policy);
  66         }
  67
  68         public void addAcls(ArrayList<Tuple<DatatypeExpr,DatatypeExpr>> acls){
  69                 this.acls.addAll(acls);
  70         }
  71
  72         @Override
  73         public DatatypeExpr getZ3Node() {
  74                 return fw;
  75         }
  76
  77
  78         @Override
  79         protected void addConstraints(Solver solver) {
  80                         BoolExpr[] constr = new BoolExpr[constraints.size()];
  81                     solver.add(constraints.toArray(constr));
  82                     aclConstraints(solver);
  83         }
  84
  85     private void firewallSendRules (){
  86         Expr p_0 = ctx.mkConst(fw+"_firewall_send_p_0", nctx.packet);
  87         Expr n_0 = ctx.mkConst(fw+"_firewall_send_n_0", nctx.node);
  88         Expr n_1 = ctx.mkConst(fw+"_firewall_send_n_1", nctx.node);
  89         IntExpr t_0 = ctx.mkIntConst(fw+"_firewall_send_t_0");
  90         IntExpr t_1 = ctx.mkIntConst(fw+"_firewall_send_t_1");
  91         acl_func = ctx.mkFuncDecl(fw+"_acl_func", new Sort[]{nctx.address, nctx.address},ctx.mkBoolSort());
  92
  93         //Constraint1           send(fw, n_0, p, t_0)  -> (exist n_1,t_1 : (recv(n_1, fw, p, t_1) &&
  94         //                              t_1 < t_0 && !acl_func(p.src,p.dest))
  95         constraints.add(
  96                 ctx.mkForall(new Expr[]{n_0, p_0, t_0},
  97                     ctx.mkImplies(
  98                         (BoolExpr)nctx.send.apply(new Expr[]{ fw, n_0, p_0, t_0}),
  99                         ctx.mkExists(new Expr[]{t_1},
 100                                         ctx.mkAnd(ctx.mkLt(t_1,t_0),
 101                                                                 ctx.mkExists(new Expr[]{n_1},
 102                                                                                 nctx.recv.apply(n_1, fw, p_0, t_1),1,null,null,null,null),
 103                                                                 ctx.mkNot((BoolExpr)acl_func.apply(nctx.pf.get("src").apply(p_0), nctx.pf.get("dest").apply(p_0)))),1,null,null,null,null)),1,null,null,null,null));
 104
 105     }
 106
 107     private void aclConstraints(Solver solver){
 108         if (acls.size() == 0)
 109             return;
 110         Expr a_0 = ctx.mkConst(fw+"_firewall_acl_a_0", nctx.address);
 111         Expr a_1 = ctx.mkConst(fw+"_firewall_acl_a_1", nctx.address);
 112         BoolExpr[] acl_map = new BoolExpr[acls.size()];
 113         for(int y=0;y<acls.size();y++){
 114                 Tuple<DatatypeExpr,DatatypeExpr> tp = acls.get(y);
 115                 acl_map[y] = ctx.mkOr(ctx.mkAnd(ctx.mkEq(a_0,tp._1),ctx.mkEq(a_1,tp._2)), ctx.mkAnd(ctx.mkEq(a_0,tp._2),ctx.mkEq(a_1,tp._1)));
 116         }
 117         //Constraint2           acl_func(a_0,a_1) == or(foreach ip1,ip2 in acl_map ((a_0 == ip1 && a_1 == ip2)||(a_0 == ip2 && a_1 == ip1)))
 118         solver.add(ctx.mkForall(new Expr[]{a_0, a_1},
 119                                                         ctx.mkEq(
 120                                                                         acl_func.apply(a_0, a_1),
 121                                                                         ctx.mkOr(acl_map)),1,null,null,null,null));
 122     }
 123 }