1 /*******************************************************************************
2 * Copyright (c) 2017 Politecnico di Torino and others.
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 *******************************************************************************/
10 package mcnet.components;
12 import java.util.ArrayList;
13 import java.util.HashMap;
14 import java.util.List;
16 import com.microsoft.z3.BoolExpr;
17 import com.microsoft.z3.Constructor;
18 import com.microsoft.z3.Context;
19 import com.microsoft.z3.DatatypeExpr;
20 import com.microsoft.z3.DatatypeSort;
21 import com.microsoft.z3.EnumSort;
22 import com.microsoft.z3.Expr;
23 import com.microsoft.z3.FuncDecl;
24 import com.microsoft.z3.IntExpr;
25 import com.microsoft.z3.Solver;
26 import com.microsoft.z3.Sort;
28 import mcnet.netobjs.DumbNode;
31 * Basic fields and other things required for model checking.
34 public class NetContext extends Core{
37 List<BoolExpr> constraints;
40 public HashMap<String,NetworkObject> nm; //list of nodes, callable by node name
41 public HashMap<String,DatatypeExpr> am; // list of addresses, callable by address name
42 public HashMap<String,FuncDecl> pf;
44 public EnumSort node,address;
45 public FuncDecl src_port,dest_port,nodeHasAddr,addrToNode,send,recv;
46 public DatatypeSort packet;
48 /* Constants definition
49 - used in the packet proto field */
50 public final int HTTP_REQUEST = 1;
51 public final int HTTP_RESPONSE = 2;
52 public final int POP3_REQUEST = 3;
53 public final int POP3_RESPONSE = 4;
56 * Context for all of the rest that follows. Every network needs one of these
60 public NetContext(Context ctx,Object[]... args ){
66 protected void init(Context ctx, Object[]... args) {
68 nm = new HashMap<String,NetworkObject>(); //list of nodes, callable by node name
69 am = new HashMap<String,DatatypeExpr>(); // list of addresses, callable by address name
70 pf= new HashMap<String,FuncDecl>() ;
72 mkTypes((String[])args[0],(String[])args[1]);
74 constraints = new ArrayList<BoolExpr>();
75 policies = new ArrayList<Core>();
81 * A policy is a collection of shared algorithms or functions used by multiple components
82 * (for instance compression or DPI policies etc).
85 public void AddPolicy (NetworkObject policy){
90 protected void addConstraints(Solver solver) {
91 BoolExpr[] constr = new BoolExpr[constraints.size()];
92 solver.add(constraints.toArray(constr));
93 for (Core policy : policies){
94 policy.addConstraints(solver);
98 private void mkTypes (String[] nodes, String[] addresses){
100 node = ctx.mkEnumSort("Node", nodes);
101 for(int i=0;i<node.getConsts().length;i++){
102 DatatypeExpr fd = (DatatypeExpr)node.getConst(i);
103 DumbNode dn =new DumbNode(ctx,new Object[]{fd});
104 nm.put(fd.toString(),dn);
107 //Addresses for this network
108 String[] new_addr = new String[addresses.length+1];
109 for(int k=0;k<addresses.length;k++)
110 new_addr[k] = addresses[k];
112 new_addr[new_addr.length-1] = "null";
113 address = ctx.mkEnumSort("Address", new_addr);
114 for(int i=0;i<address.getConsts().length;i++){
115 DatatypeExpr fd = (DatatypeExpr)address.getConst(i);
116 am.put(fd.toString(),fd);
119 // Type for packets, contains (some of these are currently represented as relations):
120 // - src: Source address
121 // - dest: Destination address
122 // - origin: Node where the data originated. (Node)
123 // - body: Packet contents. (Integer)
124 // - seq: Sequence number for packets. (Integer)
125 // - options: A representation for IP options. (Integer)
127 String[] fieldNames = new String[]{
128 "src","dest","inner_src","inner_dest","origin","orig_body","body","seq","proto","emailFrom","url","options","encrypted"};
129 Sort[] srt = new Sort[]{
130 address,address,address,address,node,ctx.mkIntSort(),ctx.mkIntSort(),ctx.mkIntSort(),
131 ctx.mkIntSort(),ctx.mkIntSort(),ctx.mkIntSort(),ctx.mkIntSort(),ctx.mkBoolSort()};
132 Constructor packetcon = ctx.mkConstructor("packet", "is_packet", fieldNames, srt, null);
133 packet = ctx.mkDatatypeSort("packet", new Constructor[] {packetcon});
135 for(int i=0;i<fieldNames.length;i++){
136 pf.put(fieldNames[i], packet.getAccessors()[0][i]); // pf to get packet's function declarations by name
139 src_port = ctx.mkFuncDecl("sport", packet, ctx.mkIntSort());
140 dest_port = ctx.mkFuncDecl("dport", packet, ctx.mkIntSort());
142 // Some commonly used relations
144 // nodeHasAddr: node -> address -> boolean
145 nodeHasAddr = ctx.mkFuncDecl("nodeHasAddr", new Sort[]{node, address},ctx.mkBoolSort());
147 // addrToNode: address -> node
148 addrToNode = ctx.mkFuncDecl("addrToNode", address, node);
150 // Send and receive both have the form:
151 // source-> destination -> packet-> int-> bool
153 // send: node -> node -> packet-> int-> bool
154 send = ctx.mkFuncDecl("send", new Sort[]{ node, node, packet, ctx.mkIntSort()},ctx.mkBoolSort());
156 // recv: node -> node -> packet-> int-> bool
157 recv = ctx.mkFuncDecl("recv", new Sort[]{ node, node, packet, ctx.mkIntSort()},ctx.mkBoolSort());
162 * Set up base conditions for the network
164 private void baseCondition(){
165 // Basic constraints for the overall model
166 Expr n_0 = ctx.mkConst("ctx_base_n_0", node);
167 Expr n_1 = ctx.mkConst("ctx_base_n_1", node);
168 Expr n_2 = ctx.mkConst("ctx_base_n_2", node);
169 Expr p_0 = ctx.mkConst("ctx_base_p_0", packet);
170 Expr p_1 = ctx.mkConst("ctx_base_p_1", packet);
171 IntExpr t_0 = ctx.mkIntConst("ctx_base_t_0");
172 IntExpr t_1 = ctx.mkIntConst("ctx_base_t_1");
174 // Constraint1 send(n_0, n_1, p_0, t_0) -> n_0 != n_1
176 ctx.mkForall(new Expr[]{n_0, n_1, p_0, t_0},
177 ctx.mkImplies((BoolExpr)send.apply(n_0, n_1, p_0, t_0),ctx.mkNot(ctx.mkEq( n_0, n_1))),1,null,null,null,null));
179 // Constraint2 recv(n_0, n_1, p_0, t_0) -> n_0 != n_1
181 ctx.mkForall(new Expr[]{n_0, n_1, p_0, t_0},
182 ctx.mkImplies((BoolExpr)recv.apply(n_0, n_1, p_0, t_0),ctx.mkNot(ctx.mkEq( n_0, n_1))),1,null,null,null,null));
184 // Constraint3 send(n_0, n_1, p_0, t_0) -> p_0.src != p_0.dest
186 ctx.mkForall(new Expr[]{n_0, n_1, p_0, t_0},
187 ctx.mkImplies((BoolExpr)send.apply(n_0, n_1, p_0, t_0),
188 ctx.mkNot(ctx.mkEq( pf.get("src").apply(p_0), pf.get("dest").apply(p_0)))),1,null,null,null,null));
190 // Constraint4 recv(n_0, n_1, p_0, t_0) -> p_0.src != p_0.dest
192 ctx.mkForall(new Expr[]{n_0, n_1, p_0, t_0},
193 ctx.mkImplies((BoolExpr)recv.apply(n_0, n_1, p_0, t_0),
194 ctx.mkNot(ctx.mkEq(pf.get("src").apply(p_0),pf.get("dest").apply(p_0)))),1,null,null,null,null));
196 // Constraint5 recv(n_0, n_1, p, t_0) -> send(n_0, n_1, p, t_1) && t_1 < t_0
198 ctx.mkForall(new Expr[]{n_0, n_1, p_0, t_0},
199 ctx.mkImplies((BoolExpr)recv.apply(n_0, n_1, p_0, t_0),
200 ctx.mkExists(new Expr[]{t_1},
201 ctx.mkAnd((BoolExpr)send.apply(n_0, n_1, p_0, t_1),
202 ctx.mkLt(t_1, t_0)),1,null,null,null,null)),1,null,null,null,null));
204 // Constraint6 send(n_0, n_1, p, t_0) -> p.src_port > 0 && p.dest_port < MAX_PORT
206 ctx.mkForall(new Expr[]{n_0, n_1, p_0, t_0},
207 ctx.mkImplies((BoolExpr)send.apply(n_0, n_1, p_0, t_0),
208 ctx.mkAnd( ctx.mkGe((IntExpr)src_port.apply(p_0),(IntExpr)ctx.mkInt(0)),
209 ctx.mkLt((IntExpr)src_port.apply(p_0),(IntExpr) ctx.mkInt(MAX_PORT)))),1,null,null,null,null));
211 // Constraint7 recv(n_0, n_1, p, t_0) -> p.src_port > 0 && p.dest_port < MAX_PORT
213 ctx.mkForall(new Expr[]{n_0, n_1, p_0, t_0},
214 ctx.mkImplies((BoolExpr)recv.apply(n_0, n_1, p_0, t_0),
215 ctx.mkAnd( ctx.mkGe((IntExpr)dest_port.apply(p_0),(IntExpr)ctx.mkInt(0)),
216 ctx.mkLt((IntExpr)dest_port.apply(p_0),(IntExpr) ctx.mkInt(MAX_PORT)))),1,null,null,null,null));
218 // Constraint8 recv(n_0, n_1, p_0, t_0) -> t_0 > 0
220 ctx.mkForall(new Expr[]{n_0, n_1, p_0, t_0},
221 ctx.mkImplies((BoolExpr)recv.apply(n_0, n_1, p_0, t_0),
222 ctx.mkGt(t_0,ctx.mkInt(0))),1,null,null,null,null));
224 // Constraint9 send(n_0, n_1, p_0, t_0) -> t_0 > 0
226 ctx.mkForall(new Expr[]{n_0, n_1, p_0, t_0},
227 ctx.mkImplies((BoolExpr)send.apply(n_0, n_1, p_0, t_0),
228 ctx.mkGt(t_0,ctx.mkInt(0))),1,null,null,null,null));
230 // Extra constriants for supporting the VPN gateway
232 ctx.mkForall(new Expr[]{n_0, n_1, p_0, t_0},
234 ctx.mkAnd((BoolExpr)send.apply(n_0, n_1, p_0, t_0),
235 ctx.mkNot(ctx.mkEq(this.pf.get("inner_src").apply(p_0), this.am.get("null")))),
236 ctx.mkNot(ctx.mkEq(this.pf.get("inner_src").apply(p_0), this.pf.get("inner_dest").apply(p_0)))),1,null,null,null,null));
239 ctx.mkForall(new Expr[]{n_0, n_1, p_0, t_0},
241 ctx.mkAnd((BoolExpr)send.apply(n_0, n_1, p_0, t_0),
242 ctx.mkEq(this.pf.get("inner_src").apply(p_0), this.am.get("null"))),
243 ctx.mkEq(this.pf.get("inner_src").apply(p_0), this.pf.get("inner_dest").apply(p_0))),1,null,null,null,null));
246 ctx.mkForall(new Expr[]{n_0, n_1, p_0, t_0},
248 ctx.mkAnd((BoolExpr)send.apply(n_0, n_1, p_0, t_0),
249 ctx.mkEq(this.pf.get("inner_dest").apply(p_0), this.am.get("null"))),
250 ctx.mkEq(this.pf.get("inner_src").apply(p_0), this.pf.get("inner_dest").apply(p_0))),1,null,null,null,null));
253 ctx.mkForall(new Expr[]{n_0, n_1, p_0, t_0},
255 ctx.mkAnd((BoolExpr)recv.apply(n_0, n_1, p_0, t_0),
256 ctx.mkNot(ctx.mkEq(this.pf.get("inner_src").apply(p_0), this.am.get("null")))),
257 ctx.mkNot(ctx.mkEq(this.pf.get("inner_src").apply(p_0), this.pf.get("inner_dest").apply(p_0)))),1,null,null,null,null));
260 ctx.mkForall(new Expr[]{n_0, n_1, p_0, t_0},
262 ctx.mkAnd((BoolExpr)recv.apply(n_0, n_1, p_0, t_0),
263 ctx.mkEq(this.pf.get("inner_src").apply(p_0), this.am.get("null"))),
264 ctx.mkEq(this.pf.get("inner_src").apply(p_0), this.pf.get("inner_dest").apply(p_0))),1,null,null,null,null));
267 ctx.mkForall(new Expr[]{n_0, n_1, p_0, t_0},
269 ctx.mkAnd((BoolExpr)recv.apply(n_0, n_1, p_0, t_0),
270 ctx.mkEq(this.pf.get("inner_dest").apply(p_0), this.am.get("null"))),
271 ctx.mkEq(this.pf.get("inner_src").apply(p_0), this.pf.get("inner_dest").apply(p_0))),1,null,null,null,null));
274 ctx.mkForall(new Expr[]{n_0, n_1, p_0, t_0, n_2, p_1, t_1},
278 (BoolExpr)send.apply(n_0, n_1, p_0, t_0),
279 (BoolExpr)this.pf.get("encrypted").apply(p_1),
280 (BoolExpr)recv.apply(n_2, n_0, p_1, t_1),
281 (BoolExpr)this.pf.get("encrypted").apply(p_0)),
283 ctx.mkEq(this.pf.get("inner_src").apply(p_1), this.pf.get("inner_src").apply(p_0)),
284 ctx.mkEq(this.pf.get("inner_dest").apply(p_1), this.pf.get("inner_dest").apply(p_0)),
285 ctx.mkEq(this.pf.get("origin").apply(p_1), this.pf.get("origin").apply(p_0)),
286 ctx.mkEq(this.pf.get("orig_body").apply(p_1), this.pf.get("orig_body").apply(p_0)),
287 ctx.mkEq(this.pf.get("body").apply(p_1), this.pf.get("body").apply(p_0)),
288 ctx.mkEq(this.pf.get("seq").apply(p_1), this.pf.get("seq").apply(p_0)),
289 ctx.mkEq(this.pf.get("proto").apply(p_1), this.pf.get("proto").apply(p_0)),
290 ctx.mkEq(this.pf.get("emailFrom").apply(p_1), this.pf.get("emailFrom").apply(p_0)),
291 ctx.mkEq(this.pf.get("url").apply(p_1), this.pf.get("url").apply(p_0)),
292 ctx.mkEq(this.pf.get("options").apply(p_1), this.pf.get("options").apply(p_0)))),1,null,null,null,null)
297 * Two packets have equal headers
302 public BoolExpr PacketsHeadersEqual(Expr p1, Expr p2){
303 return ctx.mkAnd(new BoolExpr[]{
304 ctx.mkEq(pf.get("src").apply(p1), pf.get("src").apply(p2)),
305 ctx.mkEq(pf.get("dest").apply(p1), pf.get("dest").apply(p2)),
306 ctx.mkEq(pf.get("origin").apply(p1), pf.get("origin").apply(p2)),
307 ctx.mkEq(pf.get("seq").apply(p1), pf.get("seq").apply(p2)),
308 ctx.mkEq(src_port.apply(p1), src_port.apply(p2)),
309 ctx.mkEq(dest_port.apply(p1), dest_port.apply(p2)),
310 ctx.mkEq(pf.get("options").apply(p1), pf.get("options").apply(p2))});
314 * Two packets have equal bodies
319 public BoolExpr PacketContentEqual(Expr p1, Expr p2){
320 return ctx.mkEq(pf.get("body").apply(p1), pf.get("body").apply(p2));
324 /* seems to be useless
326 public Function failurePredicate (NetContext context)
328 return (NetworkObject node) -> ctx.mkNot(context.failed (node.z3Node));
332 public BoolExpr destAddrPredicate (Expr p, DatatypeExpr address){
333 return ctx.mkEq(pf.get("dest").apply(p),address);
336 public BoolExpr srcAddrPredicate (Expr p, DatatypeExpr address){
337 return ctx.mkEq(pf.get("src").apply(p),address);