/*
UDP_Clie.c: UDP client demo program for uPAC-5000 series module

Compiler: BC++ 3.1, 
          Turbo C++ 1.01 (3.01)
          MSVC 1.52
      
Compile mode: large

Project: UDP_Clie.c 
         ..\..\..\Lib\uPAC5000.lib
         ..\..\Lib\tcp_dm32.lib
         
Description
    UDP Demo of using sendto() and recvfrom() functions.
    The acccept() and connect() functions isn't needed here since recvfrom() establishes the connection.

 >> int recvfrom(int s, char *buf, int len, int flags, struct sockaddr *from, int *fromlen);
    Receives a message from a connection. The recvfrom() function allows a connection to be made and a 
    message to be read from the connection. The flag MSG_WAITALL is not supported.
    
    Parameters:
      s     socket identifier;
      buf   Buffer in which information will be stored.
      len   Number of bytes to receive.
      flags Specifies optional behavior:
		    MSG_OOB returns urgent data.
		    MSG_PEEK returns information,allowing it to be read again on a subsequent call.
      from  Specifies the remote host to which the connection should be made.
      fromlen  Size of the from data structure.
    
    The finnal two arguments to recvfrom are similar to the final two arguments accept.
    
    Return Value:
       -1 Error.
      >=0 Number of bytes received.
      
 >> int sendto(int s, char *buf, int len, int flags, struct sockaddr *to, int tolen);
    Send a message. The sendto()function allows a connection to be made and a message to Be written to 
    the connection.
    
    Parameters:
      s     Socket identifier.
      buf   Buffer from which information will be sent.
      len   Number of bytes to send.
      flags Specifies optional behavior:
		    MSG_OOB sends the data as urgent data.
		    MSG_DONTROUTE ensures that the message is not sent through a default router.
      to    Specifies the remote host to which the connection should be made.
      tolen Size of the to data structure.

    Return Value:
       -1 Error.
      >=0 Number of bytes sent.
      
[Jan 05, 2012] by Liam
*/

#include <stdlib.h>
#include "..\..\..\lib\upac5000.h"
#include "..\..\lib\Tcpip32.h"

#define BUFSIZE     1024        // read/write buffer size
#define SERVICE     23       // define the service port for BBS Server

fd_set rfds;    // set of socket file descriptors for reading

unsigned long t1;
struct sockaddr_in sin;

char *ipaddr="10.1.119.78";

// when client is connected, receive data
int do_receive(int skt)
{
    int err;
    int sin_len=sizeof(sin);
    char buf[BUFSIZE];

    err=recvfrom(skt, buf, sizeof(buf), 0, (struct sockaddr*) &sin, &sin_len);

    if(err==0)
    {
        // disconnected
        shutdown(skt, 0);
        closesocket(skt);
        
        FD_CLR(skt, &rfds);
        
        return err;
    }
    else if(err<0)
    {
        // read error
        shutdown(skt, 0);
        closesocket(skt);
        
        FD_CLR(skt, &rfds);
    
        return err;
    }
    else
    {
        buf[err]=0;
        Print("%s\r\n", buf);
    }
    
    return 0;
}

void main(int argc, char *argv[])
{
    struct sockaddr_in ssin;    // client Internet endpoing address
    int client;
    int i, err, iQuit=0;
    
    InitLib();
  
    if(argc>1) 
        ipaddr=argv[1];
    
    if((err=NetStart())<0)
    {
        Print("Inint Ethernet error.\r\n");
        return;
    }

    err=client=socket(PF_INET, SOCK_DGRAM, 0); // UDP/IP
    if(client<0)
    {
        Print("can't create socket! error %d\r\n", err);
        Nterm();
        
        return;
    }

    // addressing for master socket
    memset(&sin, 0, sizeof(sin));   // bzero is a unix system call
    sin.sin_family=AF_INET;
    sin.sin_addr.s_addr=inet_addr(ipaddr);
    sin.sin_port=htons(SERVICE);
    
    t1=GetTimeTicks();

    if(connect(client, (struct sockaddr *) &sin, sizeof(sin)))
    {
        // on success return 0
        extern int errno;
        
        Print("connect() failed: %d\n", errno);
        return;
    }
    else
        Print("connect() success, time=%lu ms\n", GetTimeTicks()-t1);

    while(!iQuit)
    {
        if(Kbhit())
        {
            switch(Getch())
            {
                // press 'ESC' key to terminate the program
                case 27:
                    iQuit=1;
                    break;
                
                case 'a':
                case 'A': 
                    err=writesocket(client, "10", 2);
                    do_receive(client);
                    break;
                
                case 'b':
                case 'B': 
                    err=writesocket(client, "01", 2);
                    do_receive(client);
                    break;
                
                default:
                    err=writesocket(client, "[1234567890]", 12);
                    break;
            }
        }
    }
    
    closesocket(client);
    Nterm();
}