ex_tcp_client.c

This example program shows how to use the TCP/IP stack in client mode. It sends a single TCP message after the server's MAC address has been resolved via ARP. The message is sent to socket 10.1.0.101:54124 (IP address 10.1.0.101, port 54124).

#include "net\stacktsk.h"
#include "net\tick.h"
#include "net\helpers.h"
#include "net\tcp.h"
#include "net\arp.h"
#include "net\arptsk.h"

//Create a TCP socket for receiving and sending data
static TCP_SOCKET tcpSocketUser = INVALID_SOCKET;

//TCP State machine
#define SM_TCP_SEND_ARP     0
#define SM_TCP_WAIT_RESOLVE 1
#define SM_TCP_RESOLVED     2
#define SM_TCP_SENT         3
static BYTE smTcp = SM_TCP_SEND_ARP;

//Timers
TICK8  tsecArpRequested = 0;   //Time last ARP request was sent
TICK16 tsecMsgSent = 0;        //Time last message was sent

void tcpExample(void)
{
    BYTE c;
    NODE_INFO tcpServerNode;

    //Initialize remote IP and address with 10.1.0.101. The MAC address is
    //is not intialized yet, but after we receive an ARP responce.
    tcpServerNode.IPAddr.v[0] = 10;
    tcpServerNode.IPAddr.v[1] = 1;
    tcpServerNode.IPAddr.v[2] = 0;
    tcpServerNode.IPAddr.v[3] = 101;

    tcpSocketUser = INVALID_SOCKET;

    //Infinite loop. Check if anything is received on TCP port
    while(1)
    {
        switch (smTcp) {
        case SM_TCP_SEND_ARP:
            if (ARPIsTxReady()) {
                tsecArpRequested = TickGet8bitSec();   //Remember when we sent last request
                
                //Send ARP request for given IP address
                ARPResolve(&tcpServerNode.IPAddr);
                
                smTcp = SM_TCP_WAIT_RESOLVE;
            }
            break;
        case SM_TCP_WAIT_RESOLVE:
            //The IP address has been resolved, we now have the MAC address of the
            //node at 10.1.0.101
            if (ARPIsResolved(&tcpServerNode.IPAddr, &tcpServerNode.MACAddr)) {
                smTcp = SM_TCP_RESOLVED;

                //We can now connect, seeing that we have the remote server node
                //info (MAC and IP address)
                tcpSocketUser = TCPConnect(&tcpServerNode, 54124);
    
                //An error occurred during the TCPListen() function
                if (tcpSocketUser == INVALID_SOCKET) {
                    //Add user code here to take action if required!
                }
            }
            //If not resolved after 2 seconds, send next request
            else {
                if (TickGetDiff8bitSec(tsecArpRequested) >= 2) {
                    smTcp = SM_TCP_SEND_ARP;
                }
            }
            break;
        case SM_TCP_RESOLVED:
            //Checks if there is a transmit buffer ready for accepting data
            if (TCPIsPutReady(tcpSocketUser)) {
                //Send a TCP Message with "Hello"
                TCPPut(tcpSocketUser, 'H');
                TCPPut(tcpSocketUser, 'e');
                TCPPut(tcpSocketUser, 'l');
                TCPPut(tcpSocketUser, 'l');
                TCPPut(tcpSocketUser, 'o');

                //Send contents of transmit buffer, and free buffer
                TCPFlush(tcpSocketUser);
                smTcp = SM_TCP_SENT;    //Set to "message sent" state
            }
            break;
        case SM_TCP_SENT:
            //Message sent state. If the user wants to resend the message, smTcp must be reset
            //to SM_TCP_RESOLVED
            break;
        }

        //This task performs normal stack task including checking for incoming
        //packet, type of packet and calling appropriate stack entity to
        //process it.
        StackTask();
    }
}

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