/* NetEcho Program
 *
 * On Hitachi-UX
 *  cc -Aa -D_HIUX_SOURCE -o netecho netecho.c
 *
 * On WinNT/Win95 Win32 console mode using Microsoft VC++ 4.0
 *  cl -DWIN32 netecho.c wsock32.lib
 */

#include <stdio.h>
#include <memory.h>
#ifdef WIN32
#define STRICT
#include <windows.h>
#include <winsock.h>
#else
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>
#include <arpa/inet.h>
#endif

#define SEND_BUFSIZE 256
#define RECV_BUFSIZE 512

#ifndef INADDR_NONE
#define INADDR_NONE 0xffffffff   /* should be in <netinet/in.h> */
#endif

#ifndef IPPORT_ECHO
#define IPPORT_ECHO 7    /* should be in <netinet/in.h> */
#endif

#ifndef WIN32
typedef int SOCKET;
#endif

int
netstart( void )
{
#ifdef WIN32
  WSADATA wsadata;
  WORD wsaversion;

  wsaversion = 0x0101;
  return( WSAStartup( wsaversion, &wsadata ) );
#else
  return(0);
#endif
}

void
netclose( SOCKET sockfd )
{
#ifdef WIN32
  closesocket( sockfd );
  WSACleanup();
#else
  close( sockfd );
#endif
  return;
}

int
netgetn( SOCKET sockfd, char *buf, int bufsize )
{
  int n, nrecv;
  char c;

  for( n = 0; n < (bufsize - 1); n++ )
  {
    if( (nrecv = recv( sockfd, &c, 1, 0 )) == 1 )
    {
      if( c == '\0' )
      {
        *buf = '\0';
        return (n + 1);
      }
      *buf++ = c;
    }
    else if( nrecv == 0 )
    {
      /* EOF */
      *buf = '\0';
      return n;
    }
    else
    {
      /* Error */
      return(-1);
    }
  }
  *buf = '\0';
  return (n + 1);
}

int
netputn( SOCKET sockfd, char *buf, int nput )
{
  int nleft, nsend;

  nleft = nput;
  while( nleft > 0 )
  {
    nsend = send( sockfd, buf, nleft, 0 );
    if( nsend <= 0 )
    {
      /* Error */
      return( nsend );
    }
    nleft -= nsend;
    buf += nsend;
  }
  return( nput - nleft );
}

void
main( int argc, char *argv[] )
{
  unsigned long inaddr;    /* 32bit Internet Address */
  struct hostent *hp;
  SOCKET sockfd;              /* Socket file descriptor */
  struct sockaddr_in serv_addr;
  char sendbuf[SEND_BUFSIZE];
  char recvbuf[RECV_BUFSIZE];
  int nsend, nrecv, c;

  /* Check the number of arguments */
  if( argc != 2 )
  {
    fprintf( stderr, "Usage: %s hostaddress\n", argv[0] );
    return;
  }

  /* Start network module */
  if( netstart() != 0 )
  {
    fprintf( stderr, "Cannot start the network.\n" );
    return;
  }

  /* Clear the server address */
  memset( (char *)&serv_addr, 0, sizeof( serv_addr ) );

  /* Get the server address */
  if( (inaddr = inet_addr( argv[1] )) != INADDR_NONE )
  {
    /* OK, It's dotted-decimal format */
    memcpy( (char *)&serv_addr.sin_addr, (char *)&inaddr, sizeof( inaddr ) );
  }
  else
  {
    /* Try to get hostaddress by using gethostbyname */
    if( (hp = gethostbyname( argv[1] )) == NULL )
    {
#ifdef WIN32
      WSACleanup();
#endif
      fprintf( stderr, "Error to get the hostaddress of %s\n", argv[1] );
      return;
    }
    memcpy( (char *)&serv_addr.sin_addr, hp->h_addr, hp->h_length );
    printf( "IP address of %s is %s\n", argv[1],
             inet_ntoa( serv_addr.sin_addr ) );
  }

  serv_addr.sin_port = htons( IPPORT_ECHO );
  serv_addr.sin_family = AF_INET;
  
  /* Create TCP socket */
#ifdef WIN32
  if( (sockfd = socket( AF_INET, SOCK_STREAM, 0 )) == INVALID_SOCKET )
  {
    WSACleanup();
#else
  if( (sockfd = socket( AF_INET, SOCK_STREAM, 0 )) < 0 )
  {
#endif
    fprintf( stderr, "Cannot create TCP socket\n" );
    return;
  }
  
  /* Connet to the server */
  if( connect( sockfd, (struct sockaddr *)&serv_addr, sizeof( serv_addr ) )
        < 0 )
  {
    netclose( sockfd );
    fprintf( stderr, "Cannot connect to the server\n" );
    return;
  }
  printf( "Connected to the host: %s\n", argv[1] );
  nsend = 0;
  while( (c = fgetc( stdin )) != EOF )
  {
    if( c == '\n' )
    {
      sendbuf[nsend++] = 0;  /* add NULL */
      printf( "Send: %d-bytes: %s\n", nsend, sendbuf );

      /* Send data including NULL */
      if( netputn( sockfd, sendbuf, nsend ) != nsend )
      {
        /* Error */
        netclose( sockfd );
        fprintf( stderr, "Send Error\n" );
        return;
      }
      /* Clear the receive buffer */
      memset( recvbuf, 0, RECV_BUFSIZE );
      if( (nrecv = netgetn( sockfd, recvbuf, RECV_BUFSIZE )) <= 0 )
      {
        /* Error */
        netclose( sockfd );
        fprintf( stderr, "Recv Error\n" );
        return;
      }
      printf( "Recv: %d-bytes: %s\n", nrecv, recvbuf );
      nsend = 0;
    }
    else
    {
      if( nsend < (SEND_BUFSIZE - 1) )
      {
        sendbuf[nsend++] = c;
      }
    }
  }
  netclose( sockfd );
  return;
}