nat_api.c

vxworks下ppp的实现源码

	ipList = &nat.natg.ip_translation_list;
	localAddress = (IP_ADDRESS) ntohl(inet_addr(localAddr));
	globalAddress = (IP_ADDRESS) ntohl(inet_addr(globalAddr));
	if (localAddress == 0 || globalAddress == 0)
		{
		printf("Give a valid IP address.\n");
		return (ERROR);
		}

	if (match_sa_with_local_address (localAddress, ipList) != NULL ||
		match_sa_with_global_address (globalAddress, ipList) != NULL)
		{
		printf("Local/global address is in use.\n");
		return (ERROR);
		}

	/* create a new static IP translation entry */
	memset(&bind_info,0,sizeof(bind_info));
	bind_info.agent_id = 0;			/* agent is NAT */
	bind_info.type = NAT_BIND_BASIC;
	bind_info.direction = NAT_OUTBOUND;
	bind_info.protocol = IPPROTO_IP;
	bind_info.static_entry = TRUE;
	bind_info.local_addr = localAddress;
	bind_info.global_addr = globalAddress;
	
	status = natSetBind((u_long)&nat, 0, &bind_info);
	if(status != NAT_OK)
		{
		printf ("Failed to bind the requested static entry, status = %d\n", status);
		return(ERROR);
		}
						
	return (OK);
}

/******************************************************************************
Description:
	Delete an IP static address translation entry (Basic NAT only).
******************************************************************************/
STATUS natIpStaticDelete(char *localAddr, char *globalAddr)
{
	IP_ADDRESS	localAddress, globalAddress;
	IP_TRANSLATION_HEADER	*ipList;
	IP_TRANSLATION_ENTRY	*ipEntryLoc, *ipEntryGlob;
	NAT_STATUS			status;

	ipList = &nat.natg.ip_translation_list;
	localAddress = (IP_ADDRESS) ntohl(inet_addr(localAddr));
	globalAddress = (IP_ADDRESS) ntohl(inet_addr(globalAddr));

	if (localAddress == 0 || globalAddress == 0)
		{
		printf("Give a valid IP address.\n");
		return (ERROR);
		}

	ipEntryGlob = match_sa_with_global_address (globalAddress, ipList);
	if (ipEntryGlob == NULL)
	{
		printf("Given global address not found.\n");
		return (ERROR);
	}

	ipEntryLoc = match_sa_with_local_address (localAddress, ipList);
	if (ipEntryLoc == NULL)
	{
		printf("Given local address not found.\n");
		return (ERROR);
	}

	if (ipEntryGlob != ipEntryLoc)
	{
		printf("Can't find the match for given local/global address pair\n");
		return (ERROR);
	}

	if (ipEntryLoc->static_entry == FALSE)
	{
		printf("Given local/global address pair is not a static entry\n");
		return (ERROR);
	}

	status = natFreeBind((u_long)&nat, 0, ipEntryLoc->bind_id);

	if (status != NAT_OK)
	{
		printf("Failed to delete static IP entry, status = %d\n", status);
		return (ERROR);
	}

	return (OK);
}
#endif	/* _STATIC_IP_API */


/*@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
  The following NAT API functions are intended for use by software agent to
  interact with NAT core, such as calls to create TCP, UDP, and IP control
  blocks.  For example, these api functions may be called by ALG API functions
  to create a translation entry.

  NOTE:  
  Unlike the API functions defined above, all the API functions defined below 
  are not intended for user to run from the command shell.
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@*/

/*******************************************************************************
Description:

  This function is called to add a translation entry in the TCP translation list 
  (effectively to add TCP control block).  Since the tuples of address and port 
  for both the source and destination must be known, this function is intended 
  for use by an external software agent (e.g. ALG) as one does not usually 
  know what the client's port number will be (until after the packet is received).  

  If the static_entry is set to TRUE, the TCP control block will not be deleted 
  once its default time stamp expires.  Subsequent traffic to the same destination 
  from the same source will reuse the same TCP control block and reset the time 
  stamp to its default value.   

Returns:
	Pointer to the new translation entry
	NULL,	failed to add the entry (e.g. memory allocation error)
*******************************************************************************/
u_long natTcpXlatAdd(u_long localAddr, u_short localPort,
					 u_long remoteAddr, u_short remotePort, 
					 BOOL static_entry)
{
	TCP_TRANSLATION_ENTRY*	new_tcp_entry;
	TCP_TRANSLATION_HEADER* xlat_list;

	if (nat.single_global_address_enabled == TRUE)	/* NAPT */
		{
		xlat_list=&nat.nats.tcp_translation_list;
		}
	else	/* Basic NAT */
		{
		printf("This function applies to NAPT only.\n");
		return((u_long)NULL);
		}

	semTake (tcpListLock, WAIT_FOREVER);

	new_tcp_entry = new_tcp_translation_entry (
				xlat_list, htonl(localAddr), 
				htons(localPort),
				remoteAddr, htons(remotePort), 
				static_entry);

	semGive (tcpListLock);
				
	return((u_long)new_tcp_entry);
}
/**********************************************************************************
Description:
	This function is called by the external agent to delete a translation entry 
	from the TCP translation list.  This function is intended for use by an external 
	software agent (e.g. ALG) only.

Returns:
	OK,
	ERROR,	entry not found in the translation list
**********************************************************************************/
STATUS natTcpXlatDelete(u_long localAddr, u_short localPort,
							u_long remoteAddr, u_short remotePort)
{
	IP_TRANSLATION_ENTRY*	ip_entry;
	TCP_TRANSLATION_ENTRY*	tcp_entry;

	semTake (tcpListLock, WAIT_FOREVER);

	if(nat.single_global_address_enabled == TRUE)	/* NAPT */
		{
		tcp_entry = (TCP_TRANSLATION_ENTRY *) DLL_FIRST(
			(DL_LIST *) &nat.nats.tcp_translation_list);

		while (tcp_entry != NULL) 
			{
			if(tcp_entry->local_address == localAddr
				&& tcp_entry->local_port == localPort
				&& tcp_entry->remote_address == remoteAddr
				&& tcp_entry->remote_port == remotePort) 
				{
				dllRemove ((DL_LIST *) &nat.nats.tcp_translation_list, (DL_NODE *)tcp_entry);
				free(tcp_entry);
                                nat_printf(NAT_PRINTF_TRACE, "TCP entry deleted\n");
				semGive (tcpListLock);
				return(OK);
				}

			tcp_entry = (TCP_TRANSLATION_ENTRY *) DLL_NEXT(
				(DL_NODE *) tcp_entry);
			}
		}
	
	/* Basic NAT */

	ip_entry = (IP_TRANSLATION_ENTRY *) DLL_FIRST(
			(DL_LIST *) &nat.natg.ip_translation_list);

	while (ip_entry != NULL) 
		{
		tcp_entry = (TCP_TRANSLATION_ENTRY *) DLL_FIRST(
			(DL_LIST *) &ip_entry->tcp_translation_list);

		while (tcp_entry != NULL) 
			{	
			if(tcp_entry->local_address == localAddr
				&& tcp_entry->local_port == localPort
				&& tcp_entry->remote_address == remoteAddr
				&& tcp_entry->remote_port == remotePort) 
				{
				dllRemove ((DL_LIST *) &ip_entry->tcp_translation_list, (DL_NODE *)tcp_entry);
				free(tcp_entry);
				semGive (tcpListLock);
				return(OK);
				}

			tcp_entry = (TCP_TRANSLATION_ENTRY *) DLL_NEXT(
				(DL_NODE *) tcp_entry);
			}

		ip_entry = (IP_TRANSLATION_ENTRY *) DLL_NEXT(
			(DL_NODE *) ip_entry);
		}
	semGive (tcpListLock);
	return(ERROR);	/* Translation entry not found */
}

/**********************************************************************************
Description:

  This function is called to add a translation entry in the UDP translation list 
  (effectively to add UDP control block).  Since the tuples of address and port 
  for both the source and destination must be known, this function is intended 
  for use by an external software agent (e.g. ALG) as one does not usually 
  know what the client's port number will be (until after the packet is received).  

  If the static_entry is set to TRUE, the UDP control block will not be deleted 
  once its default time stamp expires.  Subsequent traffic to the same destination 
  from the same source will reuse the same UDP control block and reset the time 
  stamp to its default value.   

Returns:
	Pointer to the new translation entry
	NULL,	failed to add the entry (e.g. memory allocation error)
**********************************************************************************/
u_long natUdpXlatAdd(u_long localAddr, u_short localPort, 
					 u_long remoteAddr, u_short remotePort, BOOL static_entry)
{
	UDP_TRANSLATION_ENTRY*	new_udp_entry;
	UDP_TRANSLATION_HEADER* xlat_list;

	if (nat.single_global_address_enabled == TRUE)	/* NAPT */
		{
		xlat_list=&nat.nats.udp_translation_list;
		}
	else	/* Basic NAT */
		{
		printf("This function applies to NAPT only.\n");
		return((u_long)NULL);
		}

	semTake (udpListLock, WAIT_FOREVER);

	new_udp_entry = new_udp_translation_entry (xlat_list, htonl(localAddr), htons(localPort), 
									remoteAddr, htons(remotePort), static_entry);

	semGive (udpListLock);
				
	return((u_long)new_udp_entry);
}
/***********************************************************************************
Description:
	This function is called by the external agent to delete a translation entry 
	from the TCP translation list.  This function is intended for use by an external 
	software agent (e.g. ALG) only.

Returns:
	OK,
	ERROR,	entry not found in the translation list
***********************************************************************************/
STATUS natUdpXlatDelete(u_long localAddr, u_short localPort, 
								u_long remoteAddr, u_short remotePort)
{
	UDP_TRANSLATION_ENTRY*	udp_entry;
	
	if(nat.single_global_address_enabled == TRUE)	/* NAPT */
		{
		semTake (udpListLock, WAIT_FOREVER);

		udp_entry = (UDP_TRANSLATION_ENTRY *) DLL_FIRST(
			(DL_LIST *) &nat.nats.udp_translation_list);

		while (udp_entry != NULL) 
			{	
			if(udp_entry->local_address == localAddr
				&& udp_entry->local_port == localPort
				&& udp_entry->remote_address == remoteAddr
				&& udp_entry->remote_port == remotePort) 
				{
				dllRemove ((DL_LIST *) &nat.nats.udp_translation_list, (DL_NODE *)udp_entry);
				free(udp_entry);
                                nat_printf(NAT_PRINTF_TRACE, "UDP entry deleted\n"); 
				semGive (udpListLock);
				return(OK);
				}

			udp_entry = (UDP_TRANSLATION_ENTRY *) DLL_NEXT(
				(DL_NODE *) udp_entry);
			}
		semGive (udpListLock);
		return (ERROR);
		}

	/* Basic NAT */
	
	return(ERROR);	/* Use natXlatDelete instead */
}

/*******************************************************************************
Description:

  This function is called to add an address (IP) translation entry in the IP 
  translation list.
  
Returns:
	Pointer to the new translation entry
	NULL,	failed to add the entry (e.g. memory allocation error)
*******************************************************************************/
u_long natIpXlatAdd(u_long localAddr, BOOL static_entry)
{
	IP_TRANSLATION_ENTRY*	new_ip_entry;

	semTake (ipListLock, WAIT_FOREVER);

	new_ip_entry = new_ip_translation_entry (
						&nat.natg.ip_translation_list,
						localAddr,
						static_entry);

	semGive (ipListLock);

	return((u_long)new_ip_entry);
}

/*******************************************************************************
Description:

  This function is called to delete an address (IP) translation entry in the IP 
  translation list.
*******************************************************************************/
STATUS natIpXlatDelete(u_long localAddr)
{
	IP_TRANSLATION_ENTRY*	ip_entry;
	struct 	in_addr	iaddr;
	char	asciiAddr[INET_ADDR_LEN];

	semTake (ipListLock, WAIT_FOREVER);

	ip_entry = (IP_TRANSLATION_ENTRY *) DLL_FIRST(
			(DL_LIST *) &nat.natg.ip_translation_list);

	while (ip_entry != NULL) 
		{
		if (ip_entry->sa_local_address == localAddr)
			{
			iaddr.s_addr = htonl(ip_entry->sa_global_address);
			inet_ntoa_b(iaddr, asciiAddr);
			arpDelete(asciiAddr);
			dllRemove ((DL_LIST *) &nat.natg.ip_translation_list
				,(DL_NODE *)ip_entry);
			free(ip_entry);
			semGive (ipListLock);
			return(OK);
			}				

		ip_entry = (IP_TRANSLATION_ENTRY *) DLL_NEXT(
			(DL_NODE *) ip_entry);
		}
	semGive (ipListLock);
	return(ERROR);	/* Translation entry not found */
}

/* API to get the ethernet address of the given port number */
STATUS natEtherAddr(int portNum)
{
	struct ifnet *pIf;
	char	targetAddr[INET_ADDR_LEN];
	unsigned char	eHdr[6];
	struct 	in_addr	iaddr;
	char	buf[18];

	pIf = nat.port[portNum].ifunit;
	iaddr.s_addr = htonl(nat.port[portNum].address);
	inet_ntoa_b(iaddr, targetAddr);
	printf("internet address = %s\n", targetAddr);
	if (etherAddrResolve(pIf, targetAddr, (char *)eHdr, 2, 5) == OK)
	{		
		sprintf(buf, "%x:%x:%x:%x:%x:%x", eHdr[0], eHdr[1], eHdr[2], eHdr[3], eHdr[4], eHdr[5]);
		printf("ethernet address = ");
		printf("%s",buf);
		printf("\n");
		return(OK);
	}
	return(ERROR);
}