#include<stdio.h>
#include<string.h>
#include<stdlib.h>
#include <time.h>
#include <unistd.h>
#include<arpa/inet.h>
#include<sys/socket.h>

char* server="192.168.10.25";
unsigned port=8888;
size_t buflen=1400;


void die(char *s) { perror(s); exit(1); }

char* MakeBuf(size_t s)
{
 int i;
 char* buf =  (char*) malloc(s);
 if (!buf) die("Can't allocate memory");
 for (i = 0; i < s - 1; i++)
      buf[i] = 'a' + rand()%26;
   buf[i] = '\0';
 return buf;
}

void Usage()
{
 printf("Usage: udpsender [OPTIONS]\n"
 "OPTIONS:\n"
 "-d host - Destination host\n"
 "-p port - Destination port\n"
 "-s size - Packet size\n"
 );
}

int ParceArgs(int argc, char *argv[])
{
 int opt;
 while((opt = getopt(argc, argv, "hp:d:s:")) != -1)
  {
   switch(opt)
    {
     case 'p':
            port = atoi(optarg);
            break;
     case 's':
            buflen = atoi(optarg);
            break;
     case 'd':
            server = strdup(optarg);
            break;
     default:
            Usage();
            exit(1);
    }
  }
 return 1;
}
 
int main(int argc, char *argv[])
{
 struct sockaddr_in si;
 int s, i;
 
 ParceArgs(argc,argv);
 
 char* testmsg = MakeBuf(buflen);
 
 if ( (s=socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP)) == -1)
  { die("Error: socket()"); }
 
 memset((char *) &si, 0, sizeof(si));
 si.sin_family = AF_INET;
 si.sin_port = htons(port);
 
 if (inet_aton(server , &si.sin_addr) == 0).
  { fprintf(stderr, "inet_aton() failed\n");  exit(1); }
 
 while(1)
 {
  if ( sendto(s, testmsg, strlen(testmsg) , 0 , (struct sockaddr *) &si, sizeof(si)) == -1 )
   { die("Error: sendto()"); }
 }
   
 close(s);
 return 0;
}