#include <sys/socket.h> 
#include <netdb.h> 
#include <netinet/in.h>
#include <arpa/inet.h> 
#include <stdio.h> 
#include <unistd.h> 
#include <string.h> 
#include <errno.h>
#define BUFSIZE 8000

main(int argc, char * argv[])
{
    int  sock, nread, rc, server_len, client_len;
    int  port;
    struct sockaddr_in server, client;
    char buff[BUFSIZE];
    char hostname[64]; 
    char *str; 
    struct hostent *hp;
    int nOpt = 1;

    if (argc < 2)
    {
        printf("Useage: %s port [hostname]", argv[0]);
        exit(0);
    }
    port = atoi(argv[1]);
    gethostname(hostname, sizeof(hostname));
    if (argc >= 3)
        strcpy(hostname, argv[2]);
    hp = gethostbyname(hostname); 
    if (hp == NULL) 
    { 
        printf("\n%s: unknown host.\n", hostname); 
        exit(1); 
    } 
    
    if ((sock = socket(AF_INET, SOCK_DGRAM, 0)) < 0){
        perror("CLIENT socket ");
        exit(1);
    }
    printf("sock = %d\n",sock);
    setsockopt(sock, SOL_SOCKET, SO_BROADCAST, &nOpt, sizeof(int));

    // Somehow I need to |= ff the least significant byte and then
    // send to some port number.  This will end up broadcasting to 
    // all in the area
    
    // take a look at UMI Archives/DSS/doqmain.c.  It broadcasts to
    // an Initiator.  
    
    server.sin_family = AF_INET;
    memcpy(&server.sin_addr, hp->h_addr, hp->h_length); 
    server.sin_port  = htons(port);  
       
    // Note that we need to create a client address.
    // We didn't need to do this for connection oriented sockets
    // The connect statement did all of this stuff for us automatically
 
    client.sin_family = AF_INET;
    client.sin_addr.s_addr = htonl(INADDR_ANY);
    client.sin_port = htons(0);  // pick any free port

    // Note that we need to bind the client address to the socket
    // similar to what we have always done for servers.
    // Again, this detail was buried in the connect command for
    // connection oriented socket programming.

    if (bind(sock, (struct sockaddr *) &client, sizeof(client)) < 0)
    {
        perror("CLIENT bind ");
        close(sock);
        exit(2);
    }    
    
    for (;;)
    {
        printf("Enter buffer to send\n");
        str = fgets(buff, sizeof(buff), stdin);
        if (str == NULL) break; // shouldn't happen
        server_len = sizeof(server);

        rc = sendto(sock, buff, strlen(buff), 0, 
                (struct sockaddr *)&server, server_len);
        if (rc < 0)
        {
           perror("SERVER sendto ");
           close(sock);
           exit(5);
        }
        
        client_len = sizeof(client);
        memset(buff, 0, BUFSIZE);
        printf("msg sent and now waiting on recvfrom\n");
        nread = recvfrom (sock, buff, BUFSIZE, 0, 
                    (struct sockaddr *)&client, &client_len); 
        if (nread < 0)
        {
            perror("CLIENT recvfrom ");
            close(sock);
            exit(4);
        }  
        buff[nread] = 0;
        printf("received: %s\n", buff); 
    
    } // end of for loop
}