sics/network.c

/*--------------------------------------------------------------------------

	Some networking functions. This version for TCP/IP.
	
	


	Mark Koennecke,    October 1996

	Copyright:

	Labor fuer Neutronenstreuung
	Paul Scherrer Institut
	CH-5423 Villigen-PSI


        The authors hereby grant permission to use, copy, modify, distribute,
        and license this software and its documentation for any purpose, provided
        that existing copyright notices are retained in all copies and that this
        notice is included verbatim in any distributions. No written agreement,
        license, or royalty fee is required for any of the authorized uses.
        Modifications to this software may be copyrighted by their authors
        and need not follow the licensing terms described here, provided that
        the new terms are clearly indicated on the first page of each file where
        they apply.

        IN NO EVENT SHALL THE AUTHORS OR DISTRIBUTORS BE LIABLE TO ANY PARTY
        FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
        ARISING OUT OF THE USE OF THIS SOFTWARE, ITS DOCUMENTATION, OR ANY
        DERIVATIVES THEREOF, EVEN IF THE AUTHORS HAVE BEEN ADVISED OF THE
        POSSIBILITY OF SUCH DAMAGE.

        THE AUTHORS AND DISTRIBUTORS SPECIFICALLY DISCLAIM ANY WARRANTIES,
        INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY,
        FITNESS FOR A PARTICULAR PURPOSE, AND NON-INFRINGEMENT.  THIS SOFTWARE
        IS PROVIDED ON AN "AS IS" BASIS, AND THE AUTHORS AND DISTRIBUTORS HAVE
        NO OBLIGATION TO PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR
        MODIFICATIONS.
----------------------------------------------------------------------------*/
#include "fortify.h"
#include "network.h"
#include <sys/time.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include <ctype.h>
#include <unistd.h>
#include <netdb.h>
#include <arpa/inet.h>
#include <assert.h>
#include <errno.h>
#include <fcntl.h>

#define PORT 1
#define SOCKET 2
#define UDP 3

/* wait time [ms] between a close and the next open */
#define WAIT_CLOSE_OPEN 500 

struct timeval lastclose={-1,0};
/*-----------------------------------------------------------------------
   Redefine this function if another means of error reporting is necessary.
*/
#include "Scommon.h"
 extern void SICSLogWrite(char *pText, OutCode eCode); /* servlog.c */
 
  static void NetError(char *pText)
  {
     SICSLogWrite(pText,eError);
  }

/* ---------------------------- Local ------------------------------------
     CreateSocketAdress stolen from Tcl. Thanks to John Ousterhout
*/

static int
CreateSocketAdress(
    struct sockaddr_in *sockaddrPtr,	/* Socket address */
    char *host,				/* Host.  NULL implies INADDR_ANY */
    int port)				/* Port number */
{
    struct hostent *hostent;		/* Host database entry */
    struct in_addr addr;		/* For 64/32 bit madness */

    (void) memset((char *) sockaddrPtr, '\0', sizeof(struct sockaddr_in));
    sockaddrPtr->sin_family = AF_INET;
    sockaddrPtr->sin_port = htons((unsigned short) (port & 0xFFFF));
    if (host == NULL) {
	addr.s_addr = INADDR_ANY;
    } else {
	hostent = gethostbyname(host);
	if (hostent != NULL) {
	    memcpy((char *) &addr,
		(char *) hostent->h_addr_list[0], (size_t) hostent->h_length);
	} else {
	    addr.s_addr = inet_addr(host);
	    if (addr.s_addr == (unsigned long)-1) {
		return 0;	/* error */
	    }
	}
    }
    /*
     * There is a rumor that this assignment may require care on
     * some 64 bit machines.
     */

    sockaddrPtr->sin_addr.s_addr = addr.s_addr;
    return 1;
}
/*-------------------------------------------------------------------------*/

   mkChannel *NETOpenPort(int iPort)
   {
   	mkChannel *pRes = NULL;
   	int iRet,i;
   	struct linger lili;
   	
   	pRes = (mkChannel *)malloc(sizeof(mkChannel));
   	if(!pRes)
   	     return NULL;
   	
   	/* open a socket */     
   	pRes->sockid = socket(AF_INET,SOCK_STREAM,0);
   	if(pRes->sockid < 0)
   	{
   	    free(pRes);
   	    return NULL;
   	}
        
        /* REUSEADDR, for restarts */
        i = 1;
        setsockopt(pRes->sockid,SOL_SOCKET,SO_REUSEADDR,&i,sizeof(int));
   	
   	/* bind */     
   	memset(&(pRes->adresse),0,sizeof(struct sockaddr_in));
   	pRes->adresse.sin_family = AF_INET;
   	pRes->adresse.sin_addr.s_addr = htonl(INADDR_ANY);
   	pRes->adresse.sin_port =  htons(iPort);
        iRet = bind(pRes->sockid,(struct sockaddr *)&(pRes->adresse),
                    sizeof(struct sockaddr_in));
        if(iRet < 0)
        {
        	free(pRes);
        	return NULL;
        }
        
        /* listen */
        iRet = listen(pRes->sockid,8);
        if(iRet < 0)
        {
        	free(pRes);
        	return NULL;
        }   
        i = sizeof(struct linger);
        lili.l_onoff = 1;
        lili.l_linger = 1;
        /*
        setsockopt(pRes->sockid,SOL_SOCKET,SO_LINGER,&lili,i);
 		*/
        pRes->iType = PORT;
        pRes->lMagic = NETMAGIC;       	
       	return pRes;     
   }
/*---------------------------------------------------------------------------*/

   mkChannel *NETAccept(mkChannel *self, long timeout)
   {
         mkChannel *pRes = NULL;
         int iRet;
         fd_set lMask;
         struct timeval tmo = {1,0};
         int iLen, i;
         struct linger lili;
         
         assert(self != NULL);
         
         if(timeout >= 0)
         {
            /* select first */
            tmo.tv_usec = (timeout % 1000) * 1000;
            tmo.tv_sec = timeout / 1000;
            FD_ZERO(&lMask);
            FD_SET(self->sockid,&lMask);
            if((self->sockid >= FD_SETSIZE) || (self->sockid < 0) ) /* invalid descriptor */
            {
              return NULL; /* eof */
            }
            iRet = select( (self->sockid + 1),(fd_set *)&lMask, NULL, NULL,&tmo);
            if( iRet <= 0)
            {
         	/* failure, or no request */
         	return NULL;
            }
         }
         
         /* positive: accept */
         iLen = sizeof(struct sockaddr);
         pRes = (mkChannel *)malloc(sizeof(mkChannel));
         if(!pRes) return NULL;
          
         pRes->sockid = accept(self->sockid, 
                              (struct sockaddr *)&(pRes->adresse),
                              &iLen);
         if(pRes->sockid < 0)
         {
         	free(pRes);
         	return NULL;
         }
         /*
         i = sizeof(struct linger);
         lili.l_onoff = 1;
         lili.l_linger = 1;
         setsockopt(pRes->sockid,SOL_SOCKET,SO_LINGER,&lili,i);
         i = 1;
         setsockopt(pRes->sockid,SOL_SOCKET,SO_REUSEADDR,&i,sizeof(int));
         */
         pRes->iType =  SOCKET;
         pRes->lMagic = NETMAGIC;
         return pRes;
                            
   }  
/*--------------------------------------------------------------------------*/
   mkChannel *NETConnectWithFlags(char *name, int port, int flags)
   {
      mkChannel *pRes = NULL;
      int iRet, i, cnt;
      char pBueffel[80];
      struct hostent *pServer = NULL;
      struct linger lili;
      struct timeval now;
      long dif;
      int oldopts;
      
      assert(port > 0);
      
   /* default name to localhost */
      if(name == NULL)
      {
       strcpy(pBueffel,"localhost");
       name = pBueffel;	
      }
      
    /* new channel */  
      pRes = (mkChannel *)malloc(sizeof(mkChannel));
      if(!pRes)
            return NULL;

     /* connect */
      iRet = CreateSocketAdress(&(pRes->adresse),name,port);
      if(!iRet)
      {
      		free(pRes);
      		return NULL;
      }	
     pRes->sockid = socket(AF_INET,SOCK_STREAM,0);
     if(pRes->sockid < 0)
     {
     	free(pRes);
     	return NULL;
     }
     
     if (flags & 2) { /* wait if closed recently */
       /* workaround for a bug in Lantronix terminal server:
          if a channel is closed and reopened within short time
          the connect will be succesful, but a message will be
          sent on the channel! */
        
       if (lastclose.tv_sec >= 0) {
         gettimeofday(&now, NULL);
         dif = (now.tv_sec-lastclose.tv_sec)*1000+(now.tv_usec-lastclose.tv_usec)/1000;
         if (dif < 0) dif += 24*3600*1000;
       } else {
         dif = 0;
       }
       if (dif < WAIT_CLOSE_OPEN) {
         usleep((WAIT_CLOSE_OPEN-dif)*1000);
       }
     }
     
     if (flags & 1) { /* open in non blocking mode */
       oldopts = fcntl(pRes->sockid, F_GETFL, 0);
       fcntl(pRes->sockid, F_SETFL, oldopts | O_NONBLOCK);
     }
     
     iRet = connect(pRes->sockid,(struct sockaddr *)&(pRes->adresse),
                    sizeof(struct sockaddr_in));
      if(iRet < 0)
      {
        if (errno != EINPROGRESS) {
      	  free(pRes);
      	  return NULL;
      	}
      }
      /*
      i = sizeof(struct linger);
      lili.l_onoff = 1;
      lili.l_linger = 1;
      setsockopt(pRes->sockid,SOL_SOCKET,SO_LINGER,&lili,i);
      i = 1;
      setsockopt(pRes->sockid,SOL_SOCKET,SO_REUSEADDR,&i,sizeof(int));
      */
      pRes->iType = SOCKET;
      pRes->lMagic = NETMAGIC;
      return pRes;      
   }
/*--------------------------------------------------------------------------*/
   mkChannel *NETConnect(char *name, int port) {
     return NETConnectWithFlags(name, port, 0);
   }
/*--------------------------------------------------------------------------*/
   int NETConnectFinished(mkChannel *self) {
     fd_set wmask, rmask;
     struct timeval tmo = {0,0};
     int iret;
     int oldopts;
     
     if (self->sockid == 0) {
       errno = ENOTCONN;
       return -1;
     }
     oldopts = fcntl(self->sockid, F_GETFL, 0);
     if (! (oldopts | O_NONBLOCK)) {
       /* assume success when in blocking mode */
       return 1;
     }
     FD_ZERO(&wmask);
     FD_ZERO(&rmask);
     FD_SET(self->sockid, &wmask);
     FD_SET(self->sockid, &rmask);
     iret = select(self->sockid+1, &rmask, &wmask, NULL, &tmo);
     if (iret == 0) return 0; /* in progress */
     if (iret > 0) {
       /* the connection has either succeded or failed
          - the write flag indicates success
          - the read flag indicates, if there is already data pending
          the read flag should not appear without the write flag
       */
       if (FD_ISSET(self->sockid, &wmask)) { /* should always be true */
         if (FD_ISSET(self->sockid, &rmask)) { /* there may already be data for read */ 
           iret = recv(self->sockid, NULL, 0, 0); /* zero length, check only return value */
           if (iret >= 0) {
             iret = 1; /* success */
           } /* else failure */
         } else {
           iret = send(self->sockid, NULL, 0, 0); /* zero length, check only return value */
           if (iret >= 0) {
             iret = 1; /* success */
           } /* else failure */
         }
       }
     }
     /* reset to blocking mode */
     fcntl(self->sockid, F_SETFL, oldopts | ~ O_NONBLOCK);
     return iret;
   }
/*------------------------------------------------------------------------*/
   int VerifyChannel(mkChannel *self)
   {
     if(!self)
     {
       return 0;
     }
     if(self->lMagic != NETMAGIC)
     {
       NetError("CORRUPTED MAGIC: network channel data corrupted");
       return 0;
     }
    if( (self->sockid < 0) || (self->sockid > 65000) )
    {
      NetError("MAGIC DEAD: Invalid socket number, data corrupted");
      return 0;
    } 
    return 1;
   }   
/*------------------------------------------------------------------------*/
   int NETInfo(mkChannel *self, char *pCompost, int iBufLen)
   {

      int t;
      int len;
      struct sockaddr_in sin;
      struct hostent *host;
     
      if(!VerifyChannel(self))
      {
        return 0;
      }

      len = sizeof sin;
      if (getpeername(self->sockid, (struct sockaddr *) &sin, &len) < 0)
      {
          return 0;
      } 
      else 
      {
          if ((host = gethostbyaddr((char *) &sin.sin_addr,
                                    sizeof sin.sin_addr,
                                    AF_INET)) == NULL)
          {
              return 0;
          }    
          else 
          {
             strncpy(pCompost,host->h_name,iBufLen);
          }   
      }
      return 1;      
   }   
/*--------------------------------------------------------------------------*/
   int NETWrite(mkChannel *self, char *buffer, long lLen)
   {
        int iRet;
        fd_set lMask;
        struct timeval tmo ={0,1};
        
   
        if(!VerifyChannel(self))
        {
          return 0;
        }
        if(!(self->iType == SOCKET))
        { 
           return 0;
        }    
        
#ifndef CYGNUS
        /* setup for select first */
        tmo.tv_usec = 100;
        FD_ZERO(&lMask);
        FD_SET(self->sockid,&lMask);
        if((self->sockid >= FD_SETSIZE) || (self->sockid < 0) ) 
        /* invalid descriptor */
        {
          return -1; /* eof */
        }
        iRet = select( (self->sockid + 1),NULL, &lMask, NULL,&tmo);
        if( iRet <= 0)
        {
          /* failure, or no data */
         	return -1;
        }
        /* blocking on write */
        if(!FD_ISSET(self->sockid,&lMask))
        {
           return -2;
        }
#endif        
        iRet = send(self->sockid,buffer,lLen,0);
        if(iRet != lLen)
        {
	      if(iRet < 0)
	      {
	        if (errno != EPIPE) { /* do not write "broken pipe" error */
		  printf("System error: %s\n",strerror(errno));
		}
              } else {
                printf("Incomplete send: %d to %ld\n",iRet,lLen);
              }
              return 0;
        }
        else
        {
              return 1;
        }      	
        
   }
/* -------------------------------------------------------------------------*/
   long NETRead(mkChannel *self, char *buffer, long lLen, long timeout)
   {
      fd_set lMask;
      struct timeval tmo ={0,1};
      long iRet;
      
      if(!VerifyChannel(self))
      {
          return 0;
      }
      
      if(timeout >= 0)
      {
         /* setup for select first */
         tmo.tv_usec = (timeout % 1000) *1000;
         tmo.tv_sec = timeout / 1000;
         FD_ZERO(&lMask);
         FD_SET(self->sockid,&lMask);
         if((self->sockid >= FD_SETSIZE) || (self->sockid < 0) ) /* invalid descriptor */
         {
            return -1; /* eof */
         }
         iRet = select( (self->sockid + 1),&lMask, NULL, NULL,&tmo);
         if( iRet <= 0)
         {
            /* failure, or no data 
            printf(" %d %d\n", iRet, errno);
            */
          	return 0;
         }
      }
      
      /* data or block for read, read */
      memset(buffer,0,lLen);
      iRet = recv(self->sockid,buffer,lLen,0);
      if(iRet == 0)
      {/* eof */
         return -1;
      }
      if(iRet < 0)
      {
      	return 0;
      }
      else
      {
        return iRet;
      }
   }
/*---------------------------------------------------------------------*/
   int NETAvailable(mkChannel *self, long timeout)
   { 
      fd_set lMask;
      struct timeval tmo ={0,1};
      int iRet;
      
      if(!VerifyChannel(self))
      {
          return 0;
      }
      
      /* setup for select  */
      tmo.tv_usec = (timeout % 1000) * 1000;
      tmo.tv_sec = timeout / 1000;
      FD_ZERO(&lMask);
      FD_SET(self->sockid,&lMask);
      if((self->sockid >= FD_SETSIZE) || (self->sockid < 0) ) 
         /* invalid descriptor */
      {
            return -1; /* eof */
      }
      iRet = select( (self->sockid + 1),&lMask, NULL, NULL,&tmo);
      if( iRet < 0)
      {
         return -1;
      }
      if(FD_ISSET(self->sockid,&lMask))
      {
	return 1;
      }
      else
      {
	return 0;
      }
   }
/*-------------------------------------------------------------------------*/
int NETReadTillTerm(mkChannel *self, long timeout, 
                    char *pTerm, char *pBuffer, int iBufLen)
{
  struct timeval start, now;
  int bufPtr = 0, status, i, length, matchIndex=1;
  char c;
  long dif;

  if(!VerifyChannel(self))
  {
    return -1;
  }
  
  gettimeofday(&start, NULL);

  if (pTerm == NULL) pTerm="";
  
  length = strlen(pTerm);
  memset(pBuffer,0,iBufLen);
  
  status = NETAvailable(self,timeout); /* first time: full timeout */
  if(status <= 0) /* return on error or on timeout */
  {
    return status;
  }
  while (status > 0) 
  {
    status = recv(self->sockid,&c,1,0);
    if(status <= 0)
    {
      return status;
    }
    if ('&' != pTerm[0]) {
      for(i = 0; i < length; i++)
      {
        if(c == pTerm[i])
        {
          return bufPtr+1;
        }
      }
    } else {
      if (matchIndex == 1 && c == pTerm[1]) {
        matchIndex++;
      } else {
        if (c== pTerm[matchIndex] && matchIndex < length -1) {
          matchIndex++;
        } else {
          if (c == pTerm[matchIndex] && matchIndex == length - 1) {
            bufPtr = bufPtr - matchIndex + 1;
            pBuffer[bufPtr] = '\0';
            return bufPtr;
          } else {
            matchIndex == 1;
          }
        }
      }
    }
    if (c == 0 && *pTerm != 0)
    {
      /* a null character is an error, except when no terminator is defined (binary data) */
      return -1;
    }
    if(bufPtr >= iBufLen-1)
    {
      if (*pTerm != 0) { /* terminator expected */
        return -1; /* overflow */
      }
      pBuffer[bufPtr] = c;
      return bufPtr+1;
    }
    pBuffer[bufPtr] = c;
    bufPtr++;
    /*
      wait for more data
    */
    status = NETAvailable(self,0); /* timeout 0 (just poll) */
    if (status == 0 && timeout > 0)
    {
      gettimeofday(&now, NULL);
      dif = (now.tv_sec-start.tv_sec)*1000+(now.tv_usec-start.tv_usec)/1000;
      if (dif < 0) dif += 24*3600*1000; /* treat midnight correctly */
      if(dif > timeout)
      {
        return 0; /* timeout */
      }
      status = NETAvailable(self,timeout-dif);
    };
  };
  assert(bufPtr > 0);
  return bufPtr;
}
/*---------------------------------------------------------------------------*/
   int NETClosePort(mkChannel *self)
   {
       int iRet;

      if(!VerifyChannel(self))
      {
          return 0;
      }
       
       iRet = close(self->sockid);
       gettimeofday(&lastclose, NULL);
       self->iType = 0;
       self->sockid = 0;
       if(iRet < 0)
          return 0;
       else
          return 1;
          
   }
/* ################### UDP -functions ######################################*/
   mkChannel *UDPOpen(int iPort)
   {
   	mkChannel *pRes = NULL;
   	int iRet, i;
   	
   	pRes = (mkChannel *)malloc(sizeof(mkChannel));
   	if(!pRes)
   	     return NULL;
   	
   	/* open a socket */     
   	pRes->sockid = socket(AF_INET,SOCK_DGRAM,0);
   	if(pRes->sockid < 0)
   	{
   	    free(pRes);
   	    return NULL;
   	}
  
        /* REUSEADDR for restarting ability */
        i = 1;
        setsockopt(pRes->sockid,SOL_SOCKET,SO_REUSEADDR,&i,sizeof(int));
   	
   	assert(pRes->sockid < (sizeof(long)*8));
   	/* if this fails the masks for select will be to
   	   short.
   	*/
   	
   	
   	/* bind */     
   	memset(&(pRes->adresse),0,sizeof(struct sockaddr_in));
   	pRes->adresse.sin_family = AF_INET;
   	pRes->adresse.sin_addr.s_addr = htonl(INADDR_ANY);
   	pRes->adresse.sin_port =  htons(iPort);
        iRet = bind(pRes->sockid,(struct sockaddr *)&(pRes->adresse),
                    sizeof(struct sockaddr_in));
        if(iRet < 0)
        {
        	free(pRes);
        	return NULL;
        }

        pRes->iType = UDP;
        pRes->lMagic = NETMAGIC;
       	return pRes;     
   }    
/*--------------------------------------------------------------------------*/       
   mkChannel *UDPConnect(char *name, int port)
   {
      mkChannel *pRes = NULL;
      int iRet, i;
      char pBueffel[80];
      struct hostent *pServer = NULL;
      
      assert(port > 0);
      
   /* default name to localhost */
      if(name == NULL)
      {
       strcpy(pBueffel,"localhost");
       name = pBueffel;	
      }
      
    /* new channel */  
      pRes = (mkChannel *)malloc(sizeof(mkChannel));
      if(!pRes)
            return NULL;

     /* connect */
      iRet = CreateSocketAdress(&(pRes->adresse),name,port);
      if(!iRet)
      {
      		free(pRes);
      		return NULL;
      }	
     pRes->sockid = socket(AF_INET,SOCK_DGRAM,0);
     if(pRes->sockid < 0)
     {
     	free(pRes);
     	return NULL;
     }
     /*
     iRet = connect(pRes->sockid,(struct sockaddr *)&(pRes->adresse),
                    sizeof(struct sockaddr_in));
     */
      iRet = 1; 
      if(iRet < 0)
      {
      	  free(pRes);
      	  return NULL;
      }

/*      i = 1;
      setsockopt(pRes->sockid,SOL_SOCKET,SO_REUSEADDR,&i,sizeof(int));
*/
      pRes->iType = UDP;
      pRes->lMagic = NETMAGIC;
      return pRes;      
   } 
/*--------------------------------------------------------------------------*/      
   long UDPRead(mkChannel *self, char *buffer, long lLen, int timeout)
   {
      long lMask = 0L;
      struct timeval tmo ={0,1};
      long iRet;
      int iLang;
      
      if(!VerifyChannel(self))
      {
          return 0;
      }
      assert(self->iType == UDP);
      
      if(timeout >= 0)
      {
        /* setup for select first */
        tmo.tv_usec = (timeout % 1000) *1000;
        tmo.tv_sec = timeout / 1000;
        lMask = (1 << self->sockid);
        iRet = select( (self->sockid + 1),(fd_set *)&lMask, NULL, NULL,&tmo);
        if( iRet <= 0)
        {
           /* failure, or no data */
          	return 0;
        }
      }
      
      /* data, read */
      buffer[0] = '\0';
      iLang = sizeof(struct sockaddr_in);
      iRet = recvfrom(self->sockid,buffer,lLen,0,
                     (struct sockaddr *)&(self->adresse),
                      &iLang);
      if(iRet == 0)
      {/* eof */
         return -1;
      }
      if(iRet < 0)
      {
      	return 0;
      }
      else
      {
        buffer[iRet] = '\0';
        return iRet;
      }
   }
/*--------------------------------------------------------------------------*/
   int UDPWrite(mkChannel *self, char *buffer, long lLen)
   {
        int iRet;
   
        if(!VerifyChannel(self))
        {
           return 0;
        }
        assert(self->iType == UDP);
        
        iRet = sendto(self->sockid,buffer,lLen,0,
               (struct sockaddr *)&(self->adresse),sizeof(struct sockaddr_in));
        fsync(self->sockid);
        if(iRet < 0)
        {
              return 0;
        }
        else
        {
              return 1;
        }      	
   }
                                                                  
/* ==========================================================================

	TestCode. Compile with DBCLIENT defined to get a test client,
	with DBSERVER defined to get a test server.
*/

#ifdef DBCLIENT


  int main(int argc, char *argv[])
  {
     char pBueffel[80];
     mkChannel *pChan = NULL;
     int iRet;
     
     pChan = NETConnect("localhost",4711);
     if(!pChan)
     {
     	puts("No connection to server");
     	exit(2);
     }
     
     for( ; ; )
     {
        printf("Client> ");
        gets(pBueffel);
        if(strcmp(pBueffel,"exit") == 0)
                      break;
        iRet = NETWrite(pChan,pBueffel,strlen(pBueffel));
        if(!iRet)
             puts("Write error");
             
       iRet = NETRead(pChan,pBueffel,79,2000);
       if(iRet < -1)
       {
       	   puts("Read error");
       }      
       else if(iRet > 0)
       {
          pBueffel[iRet] = '\0';
          puts(pBueffel);
       }
     }
     NETClosePort(pChan);
     return 0;
  }
#endif

#ifdef DBSERVER
    int main(int argc, char *argv[])
    {
	mkChannel *pPort = NULL;
	mkChannel *pCon[20];
	int i,iRet, iPtr = 0;
	char pBueffel[132];
	
	pPort = NETOpenPort(4711);
	if(!pPort)
	{
          puts("Cannot start server");
	  exit(1);
	}
	
	while(1)
	{
	  /* accept new connections */
	   pCon[iPtr] = NETAccept(pPort,200);
	   if(pCon[iPtr])
	   {
	   	printf("Connection accepted on socket %d\n",pCon[iPtr]->sockid);
		iPtr++;
	   }
	   
	   /* look for messages */
	   for(i = 0; i < iPtr; i++)
	   {
	      if(pCon[i])
	      {
	        iRet = NETRead(pCon[i],pBueffel,131,200);
	        if(iRet < 0)
	        {
	          printf("closing socket %d\n",pCon[i]->sockid);
	          NETClosePort(pCon[i]);
	          free(pCon[i]);
	          pCon[i] = NULL;
	        }
	        else if(iRet > 0)
	        {
	          pBueffel[iRet] = '\0';
	          printf("Received - %s - from %d\n",pBueffel,pCon[i]->sockid);
	          NETWrite(pCon[i],"Acknowledge",strlen("Acknowledge"));
	        }
	      }  
	   }
	   
	}
		

    }
#endif