api.c

Adhoc无线网络路由协议源码

#include "api.h"
#include "common.h"
#include "raw_sock.h"
#include "tun_dev.h"
#include "packet_ops.h"
#include "utils.h"
#include "krt.h"


/* raw socket descriptor to out put packets */
int fraw ;
extern int krt ;

int route_add(addr_t d, addr_t nh, char *dev)
{
	int r=0;
	char *dev_temp=NULL;
	
#ifdef DEBUG
		fprintf(stdout, "route_add() : dev is %s \n", dev);
#endif
		
	if(nh==0)
	{
		dev_temp = (char *) malloc(4*sizeof(char));
		/* nh =0 implies defferred route, so change the device to tun */
		memset(dev_temp,0,4);
		sprintf(dev_temp,"%s",TUN_DEV_NAME);

		// FIXME : This is here becuase you cannot add a route for
		// a host like 10.0.0.23 with 0 next hop.
		nh=d ;
		r=add_kroute(d,nh,dev_temp);
		if( r >= 0)
		{
#ifdef DEBUG
			fprintf(stdout, "added defferred route for %s \n", dot_ip(d));
			system("/sbin/route -n");
#endif
		}
	} else
	{
		r = add_kroute(d,nh,dev);
		if( r >= 0)
		{
#ifdef DEBUG
			fprintf(stdout, "added normal route for %s \n", dot_ip(d));
			system("/sbin/route -n");
#endif
		}

	}
	
		return r ;
}

int
route_del(addr_t d)
{
	int r;
	r = del_kroute(d,0,0);
	if( r >= 0)
	{
#ifdef DEBUG
		fprintf(stdout, "deleted defferred route for %s \n", dot_ip(d));
		system("/sbin/route -n");
#endif
	}
	return r ;
}


int
open_route_request ()
{
	/* tun file descriptor, to read in packets */
	int ftun ;
	//FIXME : put a check to make sure that open_route_request 
	//FIXME : is not called twice from within the same program

#ifdef DEBUG
	fprintf(stdout,"\n\nIn open_route_request\n");
#endif
	
	/* Open tun device and return the descriptor */
	if ( (ftun = tun_init()) < 0) {
		perror("open_route_request(): tun_init()");
		return -1 ;
	}
	
#ifdef DEBUG
	fprintf(stdout,"open_route_request() : tun_init() done.\n");
#endif
	
	/* Open raw socket and return the descriptor */
	if ( (fraw = rawsock_init()) < 0) {
		perror("open_route_request(): rawsock_init()");
		return -1 ;
	}
	
#ifdef DEBUG
	fprintf(stdout,"open_route_request() : rawsock_init() done.\n");
#endif

 	/* for the krt socket : to add or delete routes to the kernel */
	if ((krt = init_rtsocket()) < 0)
	{	
		perror("open_route_request() : Initializing krt socket");
    	return -1; /* Unable to create socket */
	}

#ifdef DEBUG
	fprintf(stdout,"open_route_request() : init_rtsocket() done; krt ready.\n");
#endif
	
	/* initialize the data struct to store the packets */
	packet_table_init();

#ifdef DEBUG
	fprintf(stdout,"open_route_request() : packet_table_init() done.\n");
#endif

#ifdef DEBUG
	fprintf(stdout,"open_route_request() : inserting route_check module in the kernel\n");
	fprintf(stderr,"If insmod returned error, check that  route_check is properly installed\n insmod ::");
#endif
	//FIXME : find better way to insmod
	system("/sbin/insmod route_check");
	
#ifdef DEBUG
	fprintf(stdout,"open_route_request() : done.\n\n");
#endif
	
	return ftun ;
}


/* This function should be called by the routing daemon before it exits.
* It takes care of doing all the clean up job.
* It returns 0 on success,
* -1 if something unexpected occurs */
int
close_route_request(int fd)
{
	
	/* Close the tun device */
	if(close(fd) < 0 )
		perror("close_route_request() : tun device ");
#ifdef DEBUG
	fprintf(stdout,"\nclose_route_request() : tun device closed\n");
#endif

	/* Close the raw socket */
	if(close(fraw) < 0 )
		perror("close_route_request() : raw socket ");
#ifdef DEBUG
	fprintf(stdout,"close_route_request() : raw socket closed\n");
#endif

	/* destroy packet_table */
	if(destroy_packet_table() < 0)
		perror("close_route_request() : destroy_packet_table()");
#ifdef DEBUG
	fprintf(stdout,"close_route_request() : packet_table destroyed\n");
#endif

	
	/* remove the route_check module */
	// FIXME : find a way to replace the "system" call
	system("/sbin/rmmod route_check");
#ifdef DEBUG
	fprintf(stdout,"close_route_request() : route_check module removed from the  kernel\n");
#endif

	
#ifdef DEBUG
	fprintf(stdout,"close_route_request() : Route request shutdown complete. \n\n");
#endif
	
	return 0;
}



/* blocks until a route request is read from fd
* Fills in the route_info structure.
* memory should be allocated beforehand by the user ;
* return number of bytes read ;
* a negative number if there is an error.
* 0 if route_discovery is already in progress. */

int
read_route_request(int fd, struct route_info *r_info)
{
	unsigned char buf[BUFSIZE];
	unsigned char *rbuf;
	unsigned char *dest, *src;
	addr_t dest_ip=0, src_ip=0 ;
	int rlen=0;
	int retval=0;

	/* read from  the tun device
	* Note this function is called only when something is available here*/
	
#ifdef DEBUG
		fprintf(stdout, "\n read_route_request() :blocked reading from tun device\n");
#endif
		rlen = tun_in(fd, buf); 
		
		if(rlen < 0){
			perror("read_route_request() : Error reading from tun");
			exit(1);
		}
	
#ifdef DEBUG
		fprintf(stdout, "read_route_request() :read %d bytes from tun device.\n", rlen);
#endif
	
		/* We should store only the number of bytes that haven been read
		* and not the whole buf */	
		//FIXME do not forget to check if this works okay */
		rbuf = (unsigned char *) malloc(rlen*sizeof(unsigned char));
		
		memcpy(rbuf, buf, rlen);
		
				
		dest = get_dest_ip(rbuf) ;
		src =  get_src_ip(rbuf);
		
		memcpy(&dest_ip, dest, 4);
		memcpy(&src_ip, src, 4);
		
#ifdef DEBUG
	fprintf(stdout,"read_route_request() dest is %lu, %s \n",(unsigned long)dest_ip, dot_ip(dest_ip));
	fprintf(stdout,"read_route_request() src is %lu, %s \n",(unsigned long)src_ip, dot_ip(src_ip));
#endif
			
		/* write the dest_ip on fuser only if there a route_discovery
		* for that dest is not already on progress. */ 
		if(!route_discovery_pending(dest))
		{
#ifdef DEBUG
			fprintf(stdout,"route discovery is not pending\n");
#endif
			r_info->dest_ip = (unsigned long) dest_ip ;
			r_info->src_ip = (unsigned long) src_ip;
			r_info->protocol = get_protocol(rbuf);
			retval =1;
		} else
		{
#ifdef DEBUG
			fprintf(stdout,"route discovery is pending\n");
#endif
			retval=0;
		}
		
		
		/* insert rbuf in the packet table */
		if( packet_add(rbuf, rlen) < 0)
		{
			perror("Error adding to packet_table");
			return -1;
		}		
		
		
#ifdef DEBUG
		fprintf(stdout, "read_route_request() : added packet to packet_table.\n\n");
#endif

		return retval ;

}
	

/* the routing daemon informs the ODRM that route discovery is complete
* and the kernel route table has been populated 
* result argument has two values :
*  ASL_NO_ROUTE  if routing daemon could not find a route,
*  ASL_ROUTE_FOUND  if a route was found for addr_t.
*  or it wants the packet to be dropped. 
*  returns -1 if there is an error. 0 if no problem */
int
route_discovery_done(addr_t dest, int result)
{
	if((result != ASL_ROUTE_FOUND)&&(result!=ASL_NO_ROUTE))
	{
		fprintf(stderr,"route_discovery_done() : arg 2 is %d\n",result);
		perror("route_discovery_done() : argument 2 invalid\n");
		return -1 ;
	}		
	
	if( clear_packets(dest, result) < 0)
		return -1;

	return 0;
}

/* returns the idle time of the route in msec.
* vFlag argument has following meaning associated with it's values:
* vFlag = 1, retreive idle time since a packet was forwarded last to dest_ip
* vFlag = 0, retreive idle time since a packet was received last from dest_ip
* returns -1 on error or if there is no entry in /proc for that dest */
int
query_route_idle_time(addr_t dest, int recv_flag)
{
	FILE *fp;
	char sip[20];
	char title[80];
	int	 vFlag;
	u_int32_t ip ;
	// FIXME : I do not know how to scang u_int64_t 
	//u_int64_t last_use_time ;
	unsigned long last_use_time=0;
	int		idle_time = -1;
	struct in_addr inp;
	
	fp=fopen("/proc/asl/route_check","r");
	if(fp==NULL)
	{
		fprintf(stderr, "Probably the route_check module has not been insmod\n");
		perror("Opening the proc file");
		return -1 ;
	}
		
	/* ignore the first line */
	fgets(title, 120, fp); 
	
	while(fscanf(fp, "%s %lu %d\n", sip, &last_use_time, &vFlag) != EOF)
	{
#ifdef DEBUG
		fprintf(stderr, "query_route_idle_time() : %s %lu %d\n", sip, last_use_time, vFlag);
#endif
		if( inet_aton(sip, &inp) == 0)
		{
			perror("inet_aton: Invalid address");
			return -1;
		}
		
		ip=inp.s_addr ;
		
		if((ip==dest) && (recv_flag == vFlag))
		{
			idle_time = getcurrtime() - last_use_time;
		}
	}
	
	fclose(fp);
	return idle_time ;	
	
}