tcp_wsk.c

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/* ========================================================================
 * Copyright 1988-2008 University of Washington
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * 
 * ========================================================================
 */

/*
 * Program:	Winsock TCP/IP routines
 *
 * Author:	Mark Crispin from Mike Seibel's Winsock code
 *		Networks and Distributed Computing
 *		Computing & Communications
 *		University of Washington
 *		Administration Building, AG-44
 *		Seattle, WA  98195
 *		Internet: [e-mail]
 *
 * Date:	11 April 1989
 * Last Edited:	13 January 2008
 */


#define TCPMAXSEND 32768

/* Private functions */

int tcp_socket_open (struct sockaddr_in *sin,char *tmp,char *hst,
		     unsigned long port);
static char *tcp_getline_work (TCPSTREAM *stream,unsigned long *size,
			       long *contd);
long tcp_abort (TCPSTREAM *stream);
long tcp_close_socket (SOCKET *sock);
char *tcp_name (struct sockaddr_in *sin,long flag);
char *tcp_name_valid (char *s);


/* Private data */

int wsa_initted = 0;		/* init ? */
static int wsa_sock_open = 0;	/* keep track of open sockets */
static tcptimeout_t tmoh = NIL;	/* TCP timeout handler routine */
static long ttmo_read = 0;	/* TCP timeouts, in seconds */
static long ttmo_write = 0;
static long allowreversedns = T;/* allow reverse DNS lookup */
static long tcpdebug = NIL;	/* extra TCP debugging telemetry */

/* TCP/IP manipulate parameters
 * Accepts: function code
 *	    function-dependent value
 * Returns: function-dependent return value
 */

void *tcp_parameters (long function,void *value)
{
  void *ret = NIL;
  switch ((int) function) {
  case SET_TIMEOUT:
    tmoh = (tcptimeout_t) value;
  case GET_TIMEOUT:
    ret = (void *) tmoh;
    break;
  case SET_READTIMEOUT:
    ttmo_read = (long) value;
  case GET_READTIMEOUT:
    ret = (void *) ttmo_read;
    break;
  case SET_WRITETIMEOUT:
    ttmo_write = (long) value;
  case GET_WRITETIMEOUT:
    ret = (void *) ttmo_write;
    break;
  case SET_ALLOWREVERSEDNS:
    allowreversedns = (long) value;
  case GET_ALLOWREVERSEDNS:
    ret = (void *) allowreversedns;
    break;
  case SET_TCPDEBUG:
    tcpdebug = (long) value;
  case GET_TCPDEBUG:
    ret = (void *) tcpdebug;
    break;
  }
  return ret;
}

/* TCP/IP open
 * Accepts: host name
 *	    contact service name
 *	    contact port number and optional silent flag
 * Returns: TCP/IP stream if success else NIL
 */

TCPSTREAM *tcp_open (char *host,char *service,unsigned long port)
{
  TCPSTREAM *stream = NIL;
  int i;
  SOCKET sock = INVALID_SOCKET;
  int silent = (port & NET_SILENT) ? T : NIL;
  char *s;
  struct sockaddr_in sin;
  struct hostent *he;
  char hostname[MAILTMPLEN];
  char tmp[MAILTMPLEN];
  struct servent *sv = NIL;
  blocknotify_t bn = (blocknotify_t) mail_parameters (NIL,GET_BLOCKNOTIFY,NIL);
  if (!wsa_initted++) {		/* init Windows Sockets */
    WSADATA wsock;
    if (i = (int) WSAStartup (WSA_VERSION,&wsock)) {
      wsa_initted = 0;		/* in case we try again */
      sprintf (tmp,"Unable to start Windows Sockets (%d)",i);
      mm_log (tmp,ERROR);
      return NIL;
    }
  }
  port &= 0xffff;		/* erase flags */
				/* lookup service */
  if (service && (sv = getservbyname (service,"tcp")))
    port = ntohs (sin.sin_port = sv->s_port);
 				/* copy port number in network format */
  else sin.sin_port = htons ((u_short) port);
  /* The domain literal form is used (rather than simply the dotted decimal
     as with other Windows programs) because it has to be a valid "host name"
     in mailsystem terminology. */
  sin.sin_family = AF_INET;	/* family is always Internet */
				/* look like domain literal? */
  if (host[0] == '[' && host[(strlen (host))-1] == ']') {
    strcpy (tmp,host+1);	/* yes, copy number part */
    tmp[strlen (tmp)-1] = '\0';
    if ((sin.sin_addr.s_addr = inet_addr (tmp)) == INADDR_NONE) {
      sprintf (tmp,"Bad format domain-literal: %.80s",host);
      mm_log (tmp,ERROR);
      return NIL;
    }
    else {
      sin.sin_family = AF_INET;	/* family is always Internet */
      strcpy (hostname,host);
      (*bn) (BLOCK_TCPOPEN,NIL);
      sock = tcp_socket_open (&sin,tmp,hostname,port);
      (*bn) (BLOCK_NONE,NIL);
    }
  }

  else {			/* lookup host name */
    if (tcpdebug) {
      sprintf (tmp,"DNS resolution %.80s",host);
      mm_log (tmp,TCPDEBUG);
    }
    (*bn) (BLOCK_DNSLOOKUP,NIL);/* look up name */
    if (!(he = gethostbyname (lcase (strcpy (tmp,host)))))
      sprintf (tmp,"Host not found (#%d): %s",WSAGetLastError(),host);
    (*bn) (BLOCK_NONE,NIL);
    if (he) {			/* DNS resolution won? */
      if (tcpdebug) mm_log ("DNS resolution done",TCPDEBUG);
				/* copy address type */
      sin.sin_family = he->h_addrtype;
				/* copy host name */
      strcpy (hostname,he->h_name);
      wsa_sock_open++;		/* prevent tcp_close_socket() from freeing in
				   loop */
      for (i = 0; (sock == INVALID_SOCKET) && (s = he->h_addr_list[i]); i++) {
	if (i && !silent) mm_log (tmp,WARN);
	memcpy (&sin.sin_addr,s,he->h_length);
	(*bn) (BLOCK_TCPOPEN,NIL);
	sock = tcp_socket_open (&sin,tmp,hostname,port);
	(*bn) (BLOCK_NONE,NIL);
      }
      wsa_sock_open--;		/* undo protection */
    }
  }
  if (sock == INVALID_SOCKET) {	/* error? */
    if (!silent) mm_log (tmp,ERROR);
    tcp_close_socket (&sock);	/* do possible cleanup action */
  }
  else {			/* got a socket, create TCP/IP stream */
    stream = (TCPSTREAM *) memset (fs_get (sizeof (TCPSTREAM)),0,
				   sizeof (TCPSTREAM));
    stream->port = port;	/* port number */
				/* init socket */
    stream->tcpsi = stream->tcpso = sock;
    stream->ictr = 0;		/* init input counter */
				/* copy official host name */
    stream->host = cpystr (hostname);
    if (tcpdebug) mm_log ("Stream open and ready for read",TCPDEBUG);
  }
  return stream;		/* return success */
}

/* Open a TCP socket
 * Accepts: Internet socket address block
 *	    scratch buffer
 *	    host name for error message
 *	    port number for error message
 * Returns: socket if success, else -1 with error string in scratch buffer
 */

int tcp_socket_open (struct sockaddr_in *sin,char *tmp,char *hst,
		     unsigned long port)
{
  int sock;
  char *s;
  sprintf (tmp,"Trying IP address [%s]",inet_ntoa (sin->sin_addr));
  mm_log (tmp,NIL);
				/* get a TCP stream */
  if ((sock = socket (sin->sin_family,SOCK_STREAM,0)) == INVALID_SOCKET) {
    sprintf (tmp,"Unable to create TCP socket (%d)",WSAGetLastError());
    return -1;
  }
  wsa_sock_open++;		/* count this socket as open */
				/* open connection */
  if (connect (sock,(struct sockaddr *) sin,sizeof (struct sockaddr_in)) ==
      SOCKET_ERROR) {
    switch (WSAGetLastError ()){/* analyze error */
    case WSAECONNREFUSED:
      s = "Refused";
      break;
    case WSAENOBUFS:
      s = "Insufficient system resources";
      break;
    case WSAETIMEDOUT:
      s = "Timed out";
      break;
    case WSAEHOSTUNREACH:
      s = "Host unreachable";
      break;
    default:
      s = "Unknown error";
      break;
    }
    sprintf (tmp,"Can't connect to %.80s,%ld: %s (%d)",hst,port,s,
	     WSAGetLastError ());
    tcp_close_socket (&sock);	/* flush socket */
    sock = INVALID_SOCKET;
  }
  return sock;			/* return the socket */
}
  
/* TCP/IP authenticated open
 * Accepts: NETMBX specifier
 *	    service name
 *	    returned user name buffer
 * Returns: TCP/IP stream if success else NIL
 */

TCPSTREAM *tcp_aopen (NETMBX *mb,char *service,char *usrbuf)
{
  return NIL;			/* always NIL on Windows */
}

/* TCP receive line
 * Accepts: TCP stream
 * Returns: text line string or NIL if failure
 */

char *tcp_getline (TCPSTREAM *stream)
{
  unsigned long n,contd;
  char *ret = tcp_getline_work (stream,&n,&contd);
  if (ret && contd) {		/* got a line needing continuation? */
    STRINGLIST *stl = mail_newstringlist ();
    STRINGLIST *stc = stl;
    do {			/* collect additional lines */
      stc->text.data = (unsigned char *) ret;
      stc->text.size = n;
      stc = stc->next = mail_newstringlist ();
      ret = tcp_getline_work (stream,&n,&contd);
    } while (ret && contd);
    if (ret) {			/* stash final part of line on list */
      stc->text.data = (unsigned char *) ret;
      stc->text.size = n;
				/* determine how large a buffer we need */
      for (n = 0, stc = stl; stc; stc = stc->next) n += stc->text.size;
      ret = fs_get (n + 1);	/* copy parts into buffer */
      for (n = 0, stc = stl; stc; n += stc->text.size, stc = stc->next)
	memcpy (ret + n,stc->text.data,stc->text.size);
      ret[n] = '\0';
    }
    mail_free_stringlist (&stl);/* either way, done with list */
  }
  return ret;
}

/* TCP receive line or partial line
 * Accepts: TCP stream
 *	    pointer to return size
 *	    pointer to return continuation flag
 * Returns: text line string, size and continuation flag, or NIL if failure
 */

static char *tcp_getline_work (TCPSTREAM *stream,unsigned long *size,
			       long *contd)
{
  unsigned long n;
  char *s,*ret,c,d;
  *contd = NIL;			/* assume no continuation */
				/* make sure have data */
  if (!tcp_getdata (stream)) return NIL;
  for (s = stream->iptr, n = 0, c = '\0'; stream->ictr--; n++, c = d) {
    d = *stream->iptr++;	/* slurp another character */
    if ((c == '\015') && (d == '\012')) {
      ret = (char *) fs_get (n--);
      memcpy (ret,s,*size = n);	/* copy into a free storage string */
      ret[n] = '\0';		/* tie off string with null */
      return ret;
    }
  }
				/* copy partial string from buffer */
  memcpy ((ret = (char *) fs_get (n)),s,*size = n);
				/* get more data from the net */
  if (!tcp_getdata (stream)) fs_give ((void **) &ret);
				/* special case of newline broken by buffer */
  else if ((c == '\015') && (*stream->iptr == '\012')) {
    stream->iptr++;		/* eat the line feed */
    stream->ictr--;
    ret[*size = --n] = '\0';	/* tie off string with null */
  }
  else *contd = LONGT;		/* continuation needed */
  return ret;
}

/* TCP/IP receive buffer
 * Accepts: TCP/IP stream
 *	    size in bytes
 *	    buffer to read into
 * Returns: T if success, NIL otherwise
 */

long tcp_getbuffer (TCPSTREAM *stream,unsigned long size,char *s)
{
  unsigned long n;
				/* make sure socket still alive */
  if (stream->tcpsi == INVALID_SOCKET) return NIL;
				/* can transfer bytes from buffer? */
  if (n = min (size,stream->ictr)) {
    memcpy (s,stream->iptr,n);	/* yes, slurp as much as we can from it */
    s += n;			/* update pointer */
    stream->iptr +=n;
    size -= n;			/* update # of bytes to do */
    stream->ictr -=n;
  }
  if (size) {
    int i;
    fd_set fds;
    struct timeval tmo;
    time_t tc,t = time (0);
    blocknotify_t bn=(blocknotify_t) mail_parameters (NIL,GET_BLOCKNOTIFY,NIL);
    (*bn) (BLOCK_TCPREAD,NIL);
    while (size > 0) {		/* until request satisfied */
      time_t tl = time (0);
      if (tcpdebug) mm_log ("Reading TCP buffer",TCPDEBUG);
      FD_ZERO (&fds);		/* initialize selection vector */
      FD_SET (stream->tcpsi,&fds);/* set bit in selection vector */
      tmo.tv_sec = ttmo_read;
      tmo.tv_usec = 0;
				/* block and read */
      switch ((stream->tcpsi == stream->tcpso) ?
	      select (stream->tcpsi+1,&fds,0,0,
		      ttmo_read ? &tmo : (struct timeval *) 0) : 1) {
      case SOCKET_ERROR:		/* error */
	if (WSAGetLastError () != WSAEINTR) return tcp_abort (stream);
	break;
      case 0:			/* timeout */
	tc = time (0);
	if (tmoh && ((*tmoh) (tc - t,tc - tl))) break;
	return tcp_abort (stream);
      default:
	if (stream->tcpsi == stream->tcpso)
	  while (((i = recv (stream->tcpsi,s,(int) min (maxposint,size),0)) ==
		  SOCKET_ERROR) && (WSAGetLastError () == WSAEINTR));
	else while (((i = read (stream->tcpsi,s,(int) min (maxposint,size))) <
		     0) && (errno == EINTR));
	switch (i) {
	case SOCKET_ERROR:	/* error */
	case 0:			/* no data read */
	  return tcp_abort (stream);
	default:
	  s += i;		/* point at new place to write */
	  size -= i;		/* reduce byte count */
	  if (tcpdebug) mm_log ("Successfully read TCP buffer",TCPDEBUG);
	}
      }
    }
    (*bn) (BLOCK_NONE,NIL);
  }
  *s = '\0';			/* tie off string */
  return T;
}

/* TCP/IP receive data
 * Accepts: TCP/IP stream
 * Returns: T if success, NIL otherwise
 */

long tcp_getdata (TCPSTREAM *stream)
{
  struct timeval tmo;
  int i;
  fd_set fds;
  time_t tc,t = time (0);
  blocknotify_t bn = (blocknotify_t) mail_parameters (NIL,GET_BLOCKNOTIFY,NIL);
  FD_ZERO (&fds);		/* initialize selection vector */
  if (stream->tcpsi == INVALID_SOCKET) return NIL;
  (*bn) (BLOCK_TCPREAD,NIL);
  tmo.tv_sec = ttmo_read;