tcpip.c

keil LPC 2300 web application source code.

/******************************************************************
 *****                                                        *****
 *****  Name: tcpip.c                                         *****
 *****  Ver.: 1.0                                             *****
 *****  Date: 07/05/2001                                      *****
 *****  Auth: Andreas Dannenberg                              *****
 *****        HTWK Leipzig                                    *****
 *****        university of applied sciences                  *****
 *****        Germany                                         *****
 *****  Func: implements the TCP/IP-stack and provides a      *****
 *****        simple API to the user                          *****
 *****                                                        *****
 ******************************************************************/

#include "tcpip.h"
#include "EMAC.h"         // Keil: Line added
#include <string.h>       // Keil: Line added
#include <LPC23xx.h>      // Keil: Register definition file for LPC2378

const unsigned char MyMAC[6] =   // "M1-M2-M3-M4-M5-M6"
{
  MYMAC_1, MYMAC_2, MYMAC_3,
  MYMAC_4, MYMAC_5, MYMAC_6
};

// easyWEB-API function
// initalizes the LAN-controller, reset flags, starts timer-ISR

void TCPLowLevelInit(void)
{
// Keil: Timer 0 is used for TCP retransmission control
  T0MR0 = 3144000;                            // 262mSec
  T0MCR = 3;                                  // Interrupt and Reset on MR0
  T0TCR = 1;                                  // Timer0 Enable
  VICVectAddr4 = (unsigned int)TCPClockHandler;// set interrupt vector in 4
  VICIntEnable = 0x00000010;                  // Enable Timer0 Interrupt

  PCONP |= (1<<12);                           // Deliver clock to AD
  PINSEL1 = 0x00014000;                       // Enable AD0 and AD1 inputs

  Init_EMAC();
  TransmitControl = 0;
  TCPFlags = 0;
  TCPStateMachine = CLOSED;
  SocketStatus = 0;
}

// easyWEB-API function
// does a passive open (listen on 'MyIP:TCPLocalPort' for an incoming
// connection)

void TCPPassiveOpen(void)
{
  if (TCPStateMachine == CLOSED)
  {
    TCPFlags &= ~TCP_ACTIVE_OPEN;                // let's do a passive open!
    TCPStateMachine = LISTENING;
    SocketStatus = SOCK_ACTIVE;                  // reset, socket now active
  }
}

// easyWEB-API function
// does an active open (tries to establish a connection between
// 'MyIP:TCPLocalPort' and 'RemoteIP:TCPRemotePort')

void TCPActiveOpen(void)
{
  if ((TCPStateMachine == CLOSED) || (TCPStateMachine == LISTENING))
  {
    TCPFlags |= TCP_ACTIVE_OPEN;                 // let's do an active open!
    TCPFlags &= ~IP_ADDR_RESOLVED;               // we haven't opponents MAC yet
  
    PrepareARP_REQUEST();                        // ask for MAC by sending a broadcast
    LastFrameSent = ARP_REQUEST;
    TCPStartRetryTimer();
    SocketStatus = SOCK_ACTIVE;                  // reset, socket now active    
  }
}

// easyWEB-API function
// closes an open connection

void TCPClose(void)
{
  switch (TCPStateMachine)
  {
    case LISTENING :
    case SYN_SENT :
    {
      TCPStateMachine = CLOSED;
      TCPFlags = 0;
      SocketStatus = 0;
      break;
    }
    case SYN_RECD :
    case ESTABLISHED :
    {
      TCPFlags |= TCP_CLOSE_REQUESTED;
      break;
    }
  }
}

// easyWEB-API function
// releases the receive-buffer and allows easyWEB to store new data
// NOTE: rx-buffer MUST be released periodically, else the other TCP
//       get no ACKs for the data it sent

void TCPReleaseRxBuffer(void)
{
  SocketStatus &= ~SOCK_DATA_AVAILABLE;
}

// easyWEB-API function
// transmitts data stored in 'TCP_TX_BUF'
// NOTE: * number of bytes to transmit must have been written to 'TCPTxDataCount'
//       * data-count MUST NOT exceed 'MAX_TCP_TX_DATA_SIZE'

void TCPTransmitTxBuffer(void)
{
  if ((TCPStateMachine == ESTABLISHED) || (TCPStateMachine == CLOSE_WAIT))
    if (SocketStatus & SOCK_TX_BUF_RELEASED)
    {
      SocketStatus &= ~SOCK_TX_BUF_RELEASED;               // occupy tx-buffer
      TCPUNASeqNr += TCPTxDataCount;                       // advance UNA
      
      TxFrame1Size = ETH_HEADER_SIZE + IP_HEADER_SIZE + TCP_HEADER_SIZE + TCPTxDataCount;
      TransmitControl |= SEND_FRAME1;
      
      LastFrameSent = TCP_DATA_FRAME;
      TCPStartRetryTimer();
    }
}

// Reads the length of the received ethernet frame and checks if the 
// destination address is a broadcast message or not
unsigned int IsBroadcast(void) {
  unsigned short RecdDestMAC[3];         // 48 bit MAC

  RecdFrameLength = StartReadFrame();

  CopyFromFrame_EMAC(&RecdDestMAC,  6);           // receive DA to see if it was a broadcast
  CopyFromFrame_EMAC(&RecdFrameMAC, 6);           // store SA (for our answer)

  if ((RecdDestMAC[0] == 0xFFFF) && 
      (RecdDestMAC[1] == 0xFFFF) && 
      (RecdDestMAC[2] == 0xFFFF)) { 
    return(1);
  } else {
    return (0);
  }
}


// easyWEB's 'main()'-function
// must be called from user program periodically (the often - the better)
// handles network, TCP/IP-stack and user events

void DoNetworkStuff(void)
{
  if (CheckFrameReceived())                      // Packet received
  {
    if (IsBroadcast()) {
      ProcessEthBroadcastFrame();
    } else {
      ProcessEthIAFrame(); 
    }
    EndReadFrame();                              // release buffer in ethernet controller
  }

  if (TCPFlags & TCP_TIMER_RUNNING)
    if (TCPFlags & TIMER_TYPE_RETRY)
    {
      if (TCPTimer > RETRY_TIMEOUT)
      {
        TCPRestartTimer();                       // set a new timeout

        if (RetryCounter)
        {
          TCPHandleRetransmission();             // resend last frame
          RetryCounter--;
        }
        else
        {
          TCPStopTimer();
          TCPHandleTimeout();
        }
      }
    }
    else if (TCPTimer > FIN_TIMEOUT)
    {
      TCPStateMachine = CLOSED;
      TCPFlags = 0;                              // reset all flags, stop retransmission...
      SocketStatus &= SOCK_DATA_AVAILABLE;       // clear all flags but data available
    }

  switch (TCPStateMachine)
  {
    case CLOSED :
    case LISTENING :
    {
      if (TCPFlags & TCP_ACTIVE_OPEN)            // stack has to open a connection?
        if (TCPFlags & IP_ADDR_RESOLVED)         // IP resolved?
          if (!(TransmitControl & SEND_FRAME2))  // buffer free?
          {
            TCPSeqNr = ((unsigned long)ISNGenHigh << 16) | (T0TC & 0xFFFF);  // Keil: changed from TAR to T0TC; 
                                                                // set local ISN
            TCPUNASeqNr = TCPSeqNr;
            TCPAckNr = 0;                                       // we don't know what to ACK!
            TCPUNASeqNr++;                                      // count SYN as a byte
            PrepareTCP_FRAME(TCP_CODE_SYN);                     // send SYN frame
            LastFrameSent = TCP_SYN_FRAME;
            TCPStartRetryTimer();                               // we NEED a retry-timeout
            TCPStateMachine = SYN_SENT;
          }
      break;
    }
    case SYN_RECD :
    case ESTABLISHED :
    {
      if (TCPFlags & TCP_CLOSE_REQUESTED)                  // user has user initated a close?
        if (!(TransmitControl & (SEND_FRAME2 | SEND_FRAME1)))   // buffers free?
          if (TCPSeqNr == TCPUNASeqNr)                          // all data ACKed?
          {
            TCPUNASeqNr++;
            PrepareTCP_FRAME(TCP_CODE_FIN | TCP_CODE_ACK);
            LastFrameSent = TCP_FIN_FRAME;
            TCPStartRetryTimer();
            TCPStateMachine = FIN_WAIT_1;
          }
      break;
    }
    case CLOSE_WAIT :
    {
      if (!(TransmitControl & (SEND_FRAME2 | SEND_FRAME1)))     // buffers free?
        if (TCPSeqNr == TCPUNASeqNr)                            // all data ACKed?
        {
          TCPUNASeqNr++;                                        // count FIN as a byte
          PrepareTCP_FRAME(TCP_CODE_FIN | TCP_CODE_ACK);        // we NEED a retry-timeout
          LastFrameSent = TCP_FIN_FRAME;                        // time to say goodbye...
          TCPStartRetryTimer();
          TCPStateMachine = LAST_ACK;
        }
      break;
    }
  }

  if (TransmitControl & SEND_FRAME2)
  {
    RequestSend(TxFrame2Size);

    if (Rdy4Tx())                                // NOTE: when using a very fast MCU, maybe
      SendFrame2();                              // the EMAC isn't ready yet, include
    else {                                       // a kind of timer or counter here
      TCPStateMachine = CLOSED;
      SocketStatus = SOCK_ERR_ETHERNET;          // indicate an error to user
      TCPFlags = 0;                              // clear all flags, stop timers etc.
    }

    TransmitControl &= ~SEND_FRAME2;             // clear tx-flag
  }

  if (TransmitControl & SEND_FRAME1)
  {
    PrepareTCP_DATA_FRAME();                     // build frame w/ actual SEQ, ACK....
    RequestSend(TxFrame1Size);
  
    if (Rdy4Tx())                                // EMAC ready to accept our frame?
      SendFrame1();                              // (see note above)
    else {
      TCPStateMachine = CLOSED;
      SocketStatus = SOCK_ERR_ETHERNET;          // indicate an error to user
      TCPFlags = 0;                              // clear all flags, stop timers etc.
    }

    TransmitControl &= ~SEND_FRAME1;             // clear tx-flag
  }
}

// easyWEB internal function
// handles an incoming broadcast frame

void ProcessEthBroadcastFrame(void)
{
  unsigned short TargetIP[2];

  if (ReadFrameBE_EMAC() == FRAME_ARP)           // get frame type, check for ARP
    if (ReadFrameBE_EMAC() == HARDW_ETH10)       // Ethernet frame
      if (ReadFrameBE_EMAC() == FRAME_IP)        // check protocol
        if (ReadFrameBE_EMAC() == IP_HLEN_PLEN)  // check HLEN, PLEN
          if (ReadFrameBE_EMAC() == OP_ARP_REQUEST)
          {
            DummyReadFrame_EMAC(6);              // ignore sender's hardware address
            CopyFromFrame_EMAC(&RecdFrameIP, 4); // read sender's protocol address
            DummyReadFrame_EMAC(6);              // ignore target's hardware address
            CopyFromFrame_EMAC(&TargetIP, 4);    // read target's protocol address
            if (!memcmp(&MyIP, &TargetIP, 4))    // is it for us?
              PrepareARP_ANSWER();               // yes->create ARP_ANSWER frame
          }
}

// easyWEB internal function
// handles an incoming frame that passed EMAC's address filter
// (individual addressed = IA)

void ProcessEthIAFrame(void)
{
  unsigned short TargetIP[2];
  unsigned char ProtocolType;

  switch (ReadFrameBE_EMAC())                     // get frame type
  {
    case FRAME_ARP :                             // check for ARP
    {
      if ((TCPFlags & (TCP_ACTIVE_OPEN | IP_ADDR_RESOLVED)) == TCP_ACTIVE_OPEN)
        if (ReadFrameBE_EMAC() == HARDW_ETH10)         // check for the right prot. etc.
          if (ReadFrameBE_EMAC() == FRAME_IP)
            if (ReadFrameBE_EMAC() == IP_HLEN_PLEN)
              if (ReadFrameBE_EMAC() == OP_ARP_ANSWER)
              {
                TCPStopTimer();                       // OK, now we've the MAC we wanted ;-)
                CopyFromFrame_EMAC(&RemoteMAC, 6);    // extract opponents MAC
                TCPFlags |= IP_ADDR_RESOLVED;