dgramrcv.c

   1 /* dgramrcv.c - receive from udp server
   2  *
   3  * author: hackbard
   4  *
   5  */
   6
   7 #include <stdio.h>
   8 #include <stdlib.h>
   9
  10 /* memset */
  11 #include <string.h>
  12
  13 /* socket and bind stuff */
  14 #include <sys/types.h>
  15 #include <sys/socket.h>
  16
  17 /* sockkaddr_in */
  18 #include <netinet/in.h>
  19
  20 /* inet_ntoa ... */
  21 #include <arpa/inet.h>
  22
  23 /* errno stuff ... */
  24 #include <errno.h>
  25
  26 /* read, close */
  27 #include <unistd.h>
  28
  29 int main(int argc, char *argv[]) {
  30   int receive_fd;
  31   struct sockaddr_in target_addr;
  32   int receive_bytes, write_bytes;
  33   socklen_t target_addr_len,optlen;
  34
  35   if(argc!=3) {
  36     printf("usage: %s <target-ip> <port>\n",argv[0]);
  37     exit(1);
  38   }
  39
  40   if((receive_fd=socket(AF_INET,SOCK_DGRAM,0)) == -1) {
  41     printf("can't open socket.\n");
  42     exit(1);
  43   }
  44
  45   optlen=1;
  46   setsockopt(receive_fd,SOL_SOCKET,SO_BROADCAST,NULL,optlen);
  47
  48   memset(&target_addr,0,sizeof(target_addr));
  49   target_addr.sin_family=AF_INET;
  50   target_addr.sin_port=htons(atoi(argv[2]));
  51   target_addr.sin_addr.s_addr=inet_addr(argv[1]);
  52   target_addr_len=sizeof(target_addr);
  53
  54   receive_bytes=1;
  55   while(receive_bytes>0) {
  56         unsigned char buf[1000];
  57         receive_bytes=recvfrom(receive_fd,buf,sizeof(buf),0,(struct sockaddr *)&target_addr,&target_addr_len);
  58         write_bytes=write(1,buf,receive_bytes);
  59   }
  60
  61   close(receive_fd);
  62   printf("connection closed ...\n");
  63   printf("%d from %d total bytes written.\n",write_bytes,receive_bytes);
  64
  65   return 0;
  66 }