bucket_lookup.c

Windows XP下的抓包程序实现

/*
 * Copyright (c) 2001 - 2003
 * NetGroup, Politecnico di Torino (Italy)
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 * notice, this list of conditions and the following disclaimer in the
 * documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the Politecnico di Torino nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */

#ifdef WIN32
#include "tme.h"
#include "bucket_lookup.h"
#endif

#ifdef __FreeBSD__

#ifdef _KERNEL
#include <net/tme/tme.h>
#include <net/tme/bucket_lookup.h>
#else
#include <tme/tme.h>
#include <tme/bucket_lookup.h>
#endif

#endif

#ifndef UNUSED
#define UNUSED(_x) (_x)
#endif


/* the key is represented by the initial and final value */
/* of the bucket. At the moment bucket_lookup is able to */
/* manage values of 16, 32 bits.                         */
uint32 bucket_lookup(uint8 *key, TME_DATA *data, MEM_TYPE *mem_ex, struct time_conv *time_ref)  
{
	uint32 value;
	uint32 i,j;
	int found=-1;
	uint32 blocks;
	uint32 block_size;
	uint8 *temp;

	UNUSED(mem_ex);

	if ((data->key_len!=1)&&  /*16 bit value*/
		(data->key_len!=2))   /*32 bit value*/
		return TME_ERROR;
	
	/*32 bit values*/
	blocks=data->filled_blocks-1;
	block_size=data->block_size;
	i=blocks/2; /*relative shift*/
	j=i;
	temp=data->shared_memory_base_address+block_size;

	if (data->key_len==2)
	{
		value=SW_ULONG_AT(key,0);
	
		if((value<SW_ULONG_AT(temp,0))||(value>SW_ULONG_AT(temp+block_size*(blocks-1),4)))
		{
			uint32 *key32=(uint32*) key;
			key32[0]=key32[1]=0;

			GET_TIME((struct timeval *)(data->shared_memory_base_address+8),time_ref);

			data->last_found=NULL;
			return TME_FALSE;
		}
			
		while(found==-1) /* search routine */
		{   
			i=(i==1)? 1:i>>1;
			if (SW_ULONG_AT(temp+block_size*j,0)>value)
				if (SW_ULONG_AT(temp+block_size*(j-1),4)<value)
					found=-2;
				else
					j-=i;
			else
				if (SW_ULONG_AT(temp+block_size*j,4)<value) 
					if (SW_ULONG_AT(temp+block_size*j,0)>value)
						found=-2;
					else
						j+=i;
				else found=j;
		}	
		if (found<0)
		{
			uint32 *key32=(uint32*) key;
			key32[0]=key32[1]=0;

			GET_TIME((struct timeval *)(data->shared_memory_base_address+8),time_ref);
			
			data->last_found=NULL;
			return TME_FALSE;
		}
	
		data->last_found=data->lut_base_address+found*sizeof(RECORD);

		COPY_MEMORY(key,temp+block_size*found,8);

		GET_TIME((struct timeval *)(temp+block_size*found+8),time_ref);

		return TME_TRUE;
	}
	else
	{
		value=SW_USHORT_AT(key,0);
	
		if((value<SW_USHORT_AT(temp,0))||(value>SW_USHORT_AT(temp+block_size*(blocks-1),2)))
		{
			uint16 *key16=(uint16*) key;
			key16[0]=key16[1]=0;
			
			GET_TIME((struct timeval *)(data->shared_memory_base_address+4),time_ref);

			data->last_found=NULL;
			return TME_FALSE;
		}
			
		while(found==-1) /* search routine */
		{   
			i=(i==1)? 1:i>>1;
			if (SW_USHORT_AT(temp+block_size*j,0)>value)
				if (SW_USHORT_AT(temp+block_size*(j-1),2)<value)
					found=-2;
				else
					j-=i;
			else
				if (SW_USHORT_AT(temp+block_size*j,2)<value) 
					if (SW_USHORT_AT(temp+block_size*j,0)>value)
						found=-2;
					else
						j+=i;
				else found=j;
		}	

		if (found<0)
		{
			uint16 *key16=(uint16*) key;
			key16[0]=key16[1]=0;

			GET_TIME((struct timeval *)(data->shared_memory_base_address+4),time_ref);

			data->last_found=NULL;
			return TME_FALSE;
		}
	
		data->last_found=data->lut_base_address+found*sizeof(RECORD);

		GET_TIME((struct timeval *)(temp+block_size*found+4),time_ref);

		COPY_MEMORY(key,temp+block_size*found,4);
		
		return TME_TRUE;
	}
		
}

uint32 bucket_lookup_insert(uint8 *key, TME_DATA *data, MEM_TYPE *mem_ex, struct time_conv *time_ref)   
{	
	RECORD *records=(RECORD*)data->lut_base_address;

	if ((data->key_len!=1)&&  /*16 bit value*/
		(data->key_len!=2))   /*32 bit value*/
		return TME_ERROR;

	if(data->key_len==2)
	{
		uint32 start,stop;
		uint8 *tmp;

		start=SW_ULONG_AT(key,0);	
		stop=SW_ULONG_AT(key,4);

		if (start>stop)
			return TME_ERROR;
		if (data->filled_entries>0)
		{
			tmp=mem_ex->buffer+SW_ULONG_AT(&records[data->filled_entries-1].block,0);		
			/*check if it is coherent with the previous block*/
			if (SW_ULONG_AT(tmp,4)>=start)
				return TME_ERROR;
		}
		
		if (data->filled_blocks==data->shared_memory_blocks)
			return TME_ERROR;

		if (data->filled_entries==data->lut_entries)
			return TME_ERROR;

		tmp=data->shared_memory_base_address+data->block_size*data->filled_blocks;		
		
		COPY_MEMORY(tmp,key,8);
		
		SW_ULONG_ASSIGN(&records[data->filled_entries].block,tmp-mem_ex->buffer);
		SW_ULONG_ASSIGN(&records[data->filled_entries].exec_fcn,data->default_exec);
		
		GET_TIME((struct timeval *)(tmp+8),time_ref);		
		
		data->filled_blocks++;
		data->filled_entries++;
		
		return TME_TRUE;
	}
	else
	{
		uint16 start,stop;
		uint8 *tmp;

		start=SW_USHORT_AT(key,0);	
		stop=SW_USHORT_AT(key,2);

		if (start>stop)
			return TME_ERROR;
		if (data->filled_entries>0)
		{
			tmp=mem_ex->buffer+SW_ULONG_AT(&records[data->filled_entries-1].block,0);		
			/*check if it is coherent with the previous block*/
			if (SW_USHORT_AT(tmp,2)>=start)
				return TME_ERROR;
		}
		
		if (data->filled_blocks==data->shared_memory_blocks)
			return TME_ERROR;

		if (data->filled_entries==data->lut_entries)
			return TME_ERROR;

		tmp=mem_ex->buffer+SW_ULONG_AT(&records[data->filled_entries].block,0);		
		
		COPY_MEMORY(tmp,key,4);
		
		SW_ULONG_ASSIGN(&records[data->filled_entries].block,tmp-mem_ex->buffer);
		SW_ULONG_ASSIGN(&records[data->filled_entries].exec_fcn,data->default_exec);
		
		GET_TIME((struct timeval *)(tmp+4),time_ref);		
		
		data->filled_blocks++;
		data->filled_entries++;
		
		return TME_TRUE;
	}
}