scyther/src/attackminimize.c

#include <stdio.h>
#include <stdlib.h>
#include "system.h"
#include "tracebuf.h"

//! Help counter for the number of unknowns.
int cUnk = 0;
//! Help counter for the number of todos.
int cTod = 0;

//! Mark all events of the same run before the event as required.
/**
 *@param sys The system.
 *@param tb The attack buffer.
 *@param ev The reference event index.
 */
void markback(const System sys, struct tracebuf *tb, int ev)
{
	int run = tb->run[ev];

	while (ev >= 0)
	{
		if (tb->run[ev] == run)
		{
			switch (tb->event[ev]->type)
			{
				case READ:
					switch (tb->status[ev])
					{
						case S_UNK:
							cUnk--;
						case S_RED:
							tb->status[ev] = S_TOD;
							cTod++;
							break;
						case S_TOD:
						case S_OKE:
							break;
					}
					break;
				case SEND:
				case CLAIM:
					if (tb->status[ev] == S_UNK)
					{
					    cUnk--;
					}
					tb->status[ev] = S_OKE;
					break;
			}
		}
		ev--;
	}
}

//! Minimize the attack.
void attackMinimize(const System sys, struct tracebuf *tb)
{
	int i;
	int j;

	cUnk = 0;
	cTod = 0;

	for (i=0; i < tb->length; i++)
	{
		switch (tb->status[i])
		{
		case S_UNK:
		    cUnk++;
		    break;
		case S_TOD:
		    cTod++;
		    break;
		default:
		    break;
		}
	}
	
	markback(sys, tb, tb->violatedclaim);

	while (cUnk + cTod > 0)
	{
		while (cTod > 0)
		{
			for (i = 0; i < tb->length; i++)
				// kies een i; laten we de eerste maar pakken
			{
				if (tb->status[i] == S_TOD)
					break;
			}
			if (i == tb->length)
			  {
			        printf("Some step error.\n");
				exit(1);
			  }
			
			j = i;
			while (j >= 0 && inKnowledge(tb->know[j], tb->event[i]->message))
			{
			    // zoek waar m in de kennis komt
			    j--;
			}
			tb->status[i] = S_OKE;
			cTod--;
			if (j>=0)
			{
			    markback(sys,tb,j);
			}
		}
		while (cTod == 0 && cUnk > 0)
		{
			for (i = tb->length-1; i>=0; i--)
				// pak laatste i
			{
				if (tb->status[i] == S_UNK)
					break;
			}
			if (i < 0)
			  {
			        printf("Some i<0 error.\n");
				exit(1);
			  }
			
			tb->status[i] = S_RED;
			cUnk--;
			tb->reallength--;

			j = tracebufRebuildKnow(tb);
			if (j>-1)
			{
			  	tb->reallength++;
				markback(sys,tb,i);
				if (j < tb->length)
				{
					tb->link[j] = (tb->link[j] > i ? tb->link[j] : i);
				}
			}
		}
	}
}