#include <stdlib.h>
#include <stdio.h>
#include <time.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/ioctl.h> 
#include <netinet/in.h>
#include <arpa/inet.h>
#include <ifaddrs.h>
#include <errno.h>
#include <net/if_dl.h>


#define IP_EN0 "192.168.0.101"
#define IP_EN1 "192.168.1.101"
#define IP_MCAST_GROUP "224.0.1.129"

#define UDP_PORT 333
char packet[400] = { "dummy" };

static int s;
/* this routine tests sending to a socket
 * which is bound to all interfaces
 */
 
int initTestAll(void)
{
	unsigned char on = 0;
	struct sockaddr_in addr;
	struct ip_mreq imr;
	struct in_addr groupAddr;

	if( (s = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP) ) == -1	)
	{
		printf("Could not create socket: %s\n",sys_errlist[errno]);
		return -1;
	}
	
   /* set non-blocking reads */ 
   on = 1;
   if( -1 == ioctl (s, FIONBIO,(int) &on))
   {
		printf("Could not set non-blocking reads: %s\n",sys_errlist[errno]);
		return -2;
   }
   
    memset(&addr, 0, sizeof(addr));
	addr.sin_family = AF_INET;
	addr.sin_addr.s_addr = htonl(INADDR_ANY);
	addr.sin_port = htons(UDP_PORT);
	
	if(bind(s, (struct sockaddr*)&addr, sizeof(struct sockaddr_in)) == -1)
	{
	  printf("failed to bind event socket %s\n",sys_errlist[errno]);
	  return -3;
	}
  
      imr.imr_interface.s_addr = htonl(INADDR_ANY); 
	  if( setsockopt(s, IPPROTO_IP, IP_MULTICAST_IF,
		(char *)&imr.imr_interface.s_addr, sizeof(struct in_addr)) == -1)
	  {
	    printf("failed to set multicast flag for interface: %s",sys_errlist[errno]);
	    return -4;
	  }
  
      if(!inet_aton(IP_MCAST_GROUP,&groupAddr))
      {
	    printf("could not convert address:  %s\n",sys_errlist[errno]);
	    return -5;
      }
      imr.imr_multiaddr.s_addr = groupAddr.s_addr;
  
	  /* join multicast group (for receiving) on specified interface */
	  if( setsockopt(s, IPPROTO_IP, IP_ADD_MEMBERSHIP, (char *)&imr, sizeof(struct ip_mreq)) == -1)
	  {
	    printf("failed to join multicast group:  %s\n",sys_errlist[errno]);
	    return -6;
	  }
	return 0;
}


int initTestEn1(void)
{
	unsigned char on = 0;
	struct sockaddr_in addr;
	struct ip_mreq imr;
	struct in_addr groupAddr,tmpAddr;

	if( (s = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP) ) == -1	)
	{
		printf("Could not create socket: %s\n",sys_errlist[errno]);
		return -1;
	}
	
   /* set non-blocking reads */ 
   on = 1;
   if( -1 == ioctl (s, FIONBIO,(int) &on))
   {
		printf("Could not set non-blocking reads: %s\n",sys_errlist[errno]);
		return -2;
   }
   
    memset(&addr, 0, sizeof(addr));
	addr.sin_family = AF_INET;

    if(!inet_aton(IP_EN1,&tmpAddr))
    {
	  printf("could not convert address:  %s\n",sys_errlist[errno]);
	  return -10;
    }
	
	addr.sin_addr.s_addr = tmpAddr.s_addr;
	addr.sin_port = htons(UDP_PORT);
	
	if(bind(s, (struct sockaddr*)&addr, sizeof(struct sockaddr_in)) == -1)
	{
	  printf("failed to bind event socket %s\n",sys_errlist[errno]);
	  return -3;
	}
  
      imr.imr_interface.s_addr = tmpAddr.s_addr; 
	  if( setsockopt(s, IPPROTO_IP, IP_MULTICAST_IF,
		(char *)&imr.imr_interface.s_addr, sizeof(struct in_addr)) == -1)
	  {
	    printf("failed to set multicast flag for interface: %s",sys_errlist[errno]);
	    return -4;
	  }
  
      if(!inet_aton(IP_MCAST_GROUP,&groupAddr))
      {
	    printf("could not convert address:  %s\n",sys_errlist[errno]);
	    return -5;
      }
      imr.imr_multiaddr.s_addr = groupAddr.s_addr;
  
	  /* join multicast group (for receiving) on specified interface */
	  if( setsockopt(s, IPPROTO_IP, IP_ADD_MEMBERSHIP, (char *)&imr, sizeof(struct ip_mreq)) == -1)
	  {
	    printf("failed to join multicast group:  %s\n",sys_errlist[errno]);
	    return -6;
	  }
	return 0;
}


int initTestEn0(void)
{
	unsigned char on = 0;
	struct sockaddr_in addr;
	struct ip_mreq imr;
	struct in_addr groupAddr,tmpAddr;

	if( (s = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP) ) == -1	)
	{
		printf("Could not create socket: %s\n",sys_errlist[errno]);
		return -1;
	}
	
   /* set non-blocking reads */ 
   on = 1;
   if( -1 == ioctl (s, FIONBIO,(int) &on))
   {
		printf("Could not set non-blocking reads: %s\n",sys_errlist[errno]);
		return -2;
   }
   
    memset(&addr, 0, sizeof(addr));
	addr.sin_family = AF_INET;

    if(!inet_aton(IP_EN0,&tmpAddr))
    {
	  printf("could not convert address:  %s\n",sys_errlist[errno]);
	  return -10;
    }
	
	addr.sin_addr.s_addr = tmpAddr.s_addr;
	addr.sin_port = htons(UDP_PORT);
	
	if(bind(s, (struct sockaddr*)&addr, sizeof(struct sockaddr_in)) == -1)
	{
	  printf("failed to bind event socket %s\n",sys_errlist[errno]);
	  return -3;
	}
  
      imr.imr_interface.s_addr = tmpAddr.s_addr; 
	  if( setsockopt(s, IPPROTO_IP, IP_MULTICAST_IF,
		(char *)&imr.imr_interface.s_addr, sizeof(struct in_addr)) == -1)
	  {
	    printf("failed to set multicast flag for interface: %s",sys_errlist[errno]);
	    return -4;
	  }
  
      if(!inet_aton(IP_MCAST_GROUP,&groupAddr))
      {
	    printf("could not convert address:  %s\n",sys_errlist[errno]);
	    return -5;
      }
      imr.imr_multiaddr.s_addr = groupAddr.s_addr;
  
	  /* join multicast group (for receiving) on specified interface */
	  if( setsockopt(s, IPPROTO_IP, IP_ADD_MEMBERSHIP, (char *)&imr, sizeof(struct ip_mreq)) == -1)
	  {
	    printf("failed to join multicast group:  %s\n",sys_errlist[errno]);
	    return -6;
	  }
	return 0;
}


void idle()
{
  struct timespec req,rem;
  req.tv_sec = 0;
  req.tv_nsec = 500000000;
  nanosleep(&req,&rem);
}
 
 /*
 * check if we are able to send multicast packets
 * 
 * @param interface_bound 0 bound to en0, 1 bound to en1, 2 bound to INADDR_ANY
 */
 
void sendTest(int interface_bound)
{
	int i;
	struct in_addr tmp;
	struct sockaddr_in addr;
	
	switch (interface_bound)
	{
		case 0:
			if(initTestEn0())
			{
				close(s);
				return;
			}
			break;
		
		case 1:
			if(initTestEn1())
			{
				close(s);
				return;
			}
			break;
			
		case 2:
			if(initTestAll())
			{
				close(s);
				return;
			}
			break;
		default:
			printf("don't know what todo\n");
	}
	
    memset(&addr, 0, sizeof(addr));
	addr.sin_family = AF_INET;
	addr.sin_port = htons(UDP_PORT);
	
	if(!inet_aton(IP_MCAST_GROUP,&tmp))
	{
		printf("Could not convert address: %s\n",sys_errlist[errno]);
		close(s);
		return;
	}

	addr.sin_addr.s_addr = tmp.s_addr;
	  
	for(i=0;i<20;i++)
	{
	  if(sendto(s, packet, sizeof(packet), 0,(struct sockaddr *)&addr, sizeof(struct sockaddr)) < 0)
	  {
	    printf("error sending multicast message %s\n",sys_errlist[errno]);
	    return;
	  }

	  idle();
	}
	
	close(s);
}

/*
 * check if we are able to recive multicast packets
 * 
 * @param interface_bound 0 bound to en0, 1 bound to en1, 2 bound to INADDR_ANY
 */

void receiveTest(int interface_bound)
{
	int i;
	struct sockaddr_in addr;
	int addr_len = sizeof(struct sockaddr),len = 0;
	
	switch (interface_bound)
	{
		case 0:
			if(initTestEn0())
			{
				close(s);
				return;
			}
			break;
		
		case 1:
			if(initTestEn1())
			{
				close(s);
				return;
			}
			break;
			
		case 2:
			if(initTestAll())
			{
				close(s);
				return;
			}
			break;
		default:
			printf("don't know what todo\n");
	}
			
  
    for(i=0;i<20;i++)
    {
	    len = recvfrom(s, packet, sizeof(packet), 0, (struct sockaddr *)&addr,(int *)&addr_len);
	    if(len > 0)
	    {
	    	printf("packet received with len %d \n",len);
	    }
	    idle();
    }
	
	close(s);
}


int main(int argc, char *argv[]) {
	
	if(argc != 3)
	{
		printf("usage: %s <r|s> <0|1|2>",argv[0]);
	}

	if(*argv[1] == 'r')
	{
		switch(*argv[2])
		{
			case '0':
			case '1':
			case '2':
				receiveTest(atoi(argv[2]));
				break;
			default:
		    	printf("unknown parameter %s \n",argv[2]);
		    	break;
		}
		
		return EXIT_SUCCESS;

	}
	
	if(*argv[1] == 's')
	{
		switch(*argv[2])
		{
			case '0':
			case '1':
			case '2':
				sendTest(atoi(argv[2]));
				break;
			default:
		    	printf("unknown parameter %s \n",argv[2]);
		    	break;
		}
		
		return EXIT_SUCCESS;
	}
	
   	printf("unknown parameter %s \n",argv[1]);
	return EXIT_SUCCESS;
}