1 /* datagram.c - datagram sockets server
13 /* socket and bind stuff */
14 #include <sys/types.h>
15 #include <sys/socket.h>
18 #include <netinet/in.h>
21 #include <arpa/inet.h>
29 int main(int argc, char *argv[]) {
31 struct sockaddr_in local_addr, remote_addr;
32 // socklen_t remote_addr_len;
33 int send_bytes, read_bytes;
36 printf("usage: %s <target-ip/broadcast-addr> <port>\n",argv[0]);
40 if((send_fd=socket(AF_INET,SOCK_DGRAM,0)) == -1) {
41 printf("can't open socket.\n");
45 memset(&local_addr,0,sizeof(local_addr));
46 local_addr.sin_family=AF_INET;
47 local_addr.sin_port=htons(atoi(argv[2]));
48 local_addr.sin_addr.s_addr=htonl(INADDR_ANY);
50 if(bind(send_fd,(struct sockaddr *)&local_addr,sizeof(local_addr))==-1) {
51 printf("unable to bind on port %d.\n",atoi(argv[1]));
56 // remote_addr_len=sizeof(remote_addr);
57 memset(&remote_addr,0,sizeof(remote_addr));
58 remote_addr.sin_family=AF_INET;
59 remote_addr.sin_port=htons(atoi(argv[2]));
60 remote_addr.sin_addr.s_addr=inet_addr(argv[1]);
65 unsigned char buf[1000];
66 read_bytes=read(0,buf,sizeof(buf));
67 send_bytes=sendto(send_fd,buf,sizeof(buf),0,&remote_addr,sizeof(remote_addr));
71 printf("connection closed ...\n");
72 printf("%d from %d total bytes sent.\n",send_bytes,read_bytes);