tcp_ami.c

这是用C编写IMAP源代码

/*
 * Program:	Amiga TCP/IP routines
 *
 * Author:	Mark Crispin
 *		Networks and Distributed Computing
 *		Computing & Communications
 *		University of Washington
 *		Administration Building, AG-44
 *		Seattle, WA  98195
 *		Internet: [e-mail]
 *
 * Date:	1 August 1988
 * Last Edited:	20 February 2004
 * 
 * The IMAP toolkit provided in this Distribution is
 * Copyright 2004 University of Washington.
 * The full text of our legal notices is contained in the file called
 * CPYRIGHT, included with this Distribution.
 */

#undef write			/* don't use redefined write() */
 
static tcptimeout_t tmoh = NIL;	/* TCP timeout handler routine */
static long ttmo_open = 0;	/* TCP timeouts, in seconds */
static long ttmo_read = 0;
static long ttmo_write = 0;
static long allowreversedns = T;/* allow reverse DNS lookup */
static long tcpdebug = NIL;	/* extra TCP debugging telemetry */

extern long maxposint;		/* get this from write.c */

/* Local function prototypes */

int tcp_socket_open (struct sockaddr_in *sin,char *tmp,int *ctr,char *hst,
		     unsigned long port);
long tcp_abort (TCPSTREAM *stream);
char *tcp_name (struct sockaddr_in *sin,long flag);
char *tcp_name_valid (char *s);

/* 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_OPENTIMEOUT:
    ttmo_open = (long) value;
  case GET_OPENTIMEOUT:
    ret = (void *) ttmo_open;
    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;
  int sock = -1;
  int ctr = 0;
  int silent = (port & NET_SILENT) ? T : NIL;
  int *ctrp = (port & NET_NOOPENTIMEOUT) ? NIL : &ctr;
  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);
  void *data;
  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 (port);
  /* The domain literal form is used (rather than simply the dotted decimal
     as with other Amiga programs) because it has to be a valid "host name"
     in mailsystem terminology. */
				/* look like domain literal? */
  if (host[0] == '[' && host[(strlen (host))-1] == ']') {
    strcpy (hostname,host+1);	/* yes, copy number part */
    hostname[(strlen (hostname))-1] = '\0';
    if ((sin.sin_addr.s_addr = inet_addr (hostname)) == -1)
      sprintf (tmp,"Bad format domain-literal: %.80s",host);
    else {
      sin.sin_family = AF_INET;	/* family is always Internet */
      strcpy (hostname,host);	/* hostname is user's argument */
      (*bn) (BLOCK_TCPOPEN,NIL);
				/* get an open socket for this system */
      sock = tcp_socket_open (&sin,tmp,ctrp,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);/* quell alarms */
    data = (*bn) (BLOCK_SENSITIVE,NIL);
    if (!(he = gethostbyname (lcase (strcpy (hostname,host)))))
      sprintf (tmp,"No such host as %.80s",host);
    (*bn) (BLOCK_NONSENSITIVE,data);
    (*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);
#ifdef HOST_NOT_FOUND		/* muliple addresses only on DNS systems */
      for (sock = -1,i = 0; (sock < 0) && (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,ctrp,hostname,port);
	(*bn) (BLOCK_NONE,NIL);
      }
#else				/* the one true address then */
      memcpy (&sin.sin_addr,he->h_addr,he->h_length);
      (*bn) (BLOCK_TCPOPEN,NIL);
      sock = tcp_socket_open (&sin,tmp,ctrp,hostname,port);
      (*bn) (BLOCK_NONE,NIL);
#endif
    }
  }
  if (sock >= 0)  {		/* won */
    stream = (TCPSTREAM *) memset (fs_get (sizeof (TCPSTREAM)),0,
				   sizeof (TCPSTREAM));
    stream->port = port;	/* port number */
				/* init sockets */
    stream->tcpsi = stream->tcpso = sock;
				/* stash in the snuck-in byte */
    if (stream->ictr = ctr) *(stream->iptr = stream->ibuf) = tmp[0];
				/* copy official host name */
    stream->host = cpystr (hostname);
    if (tcpdebug) mm_log ("Stream open and ready for read",TCPDEBUG);
  }
  else if (!silent) mm_log (tmp,ERROR);
  return stream;		/* return success */
}

/* Open a TCP socket
 * Accepts: Internet socket address block
 *	    scratch buffer
 *	    pointer to "first byte read in" storage or NIL
 *	    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,int *ctr,char *hst,
		     unsigned long port)
{
  int i,ti,sock,flgs;
  time_t now;
  struct protoent *pt = getprotobyname ("tcp");
  fd_set fds,efds;
  struct timeval tmo;
  blocknotify_t bn = (blocknotify_t) mail_parameters (NIL,GET_BLOCKNOTIFY,NIL);
  void *data = (*bn) (BLOCK_SENSITIVE,NIL);
  sprintf (tmp,"Trying IP address [%s]",inet_ntoa (sin->sin_addr));
  mm_log (tmp,NIL);
				/* make a socket */
  if ((sock = socket (sin->sin_family,SOCK_STREAM,pt ? pt->p_proto : 0)) < 0) {
    sprintf (tmp,"Unable to create TCP socket: %s",strerror (errno));
    (*bn) (BLOCK_NONSENSITIVE,data);
    return -1;
  }
  flgs = fcntl (sock,F_GETFL,0);/* get current socket flags */
				/* set non-blocking if want open timeout */
  if (ctr) fcntl (sock,F_SETFL,flgs | FNDELAY);
				/* open connection */
  while ((i = connect (sock,(struct sockaddr *) sin,
		       sizeof (struct sockaddr_in))) < 0 && (errno == EINTR));
  (*bn) (BLOCK_NONSENSITIVE,data);
  if (i < 0) switch (errno) {	/* failed? */
  case EAGAIN:			/* DG brain damage */
  case EINPROGRESS:		/* what we expect to happen */
  case EALREADY:		/* or another form of it */
  case EISCONN:			/* restart after interrupt? */
  case EADDRINUSE:		/* restart after interrupt? */
    break;			/* well, not really, it was interrupted */
  default:
    sprintf (tmp,"Can't connect to %.80s,%lu: %s",hst,port,strerror (errno));
    close (sock);		/* flush socket */
    return -1;
  }

  if (ctr) {			/* want open timeout */
    now = time (0);		/* open timeout */
    ti = ttmo_open ? now + ttmo_open : 0;
    tmo.tv_usec = 0;
    FD_ZERO (&fds);		/* initialize selection vector */
    FD_ZERO (&efds);		/* handle errors too */
    FD_SET (sock,&fds);		/* block for error or readable */
    FD_SET (sock,&efds);
    do {			/* block under timeout */
      tmo.tv_sec = ti ? ti - now : 0;
      i = select (sock+1,&fds,0,&efds,ti ? &tmo : 0);
      now = time (0);		/* fake timeout if interrupt & time expired */
      if ((i < 0) && (errno == EINTR) && ti && (ti <= now)) i = 0;
    } while ((i < 0) && (errno == EINTR));
    if (i > 0) {		/* success, make sure really connected */
      fcntl (sock,F_SETFL,flgs);/* restore blocking status */
      /* This used to be a zero-byte read(), but that crashes Solaris */
				/* get socket status */
      while (((i = *ctr = read (sock,tmp,1)) < 0) && (errno == EINTR));
    }	
    if (i <= 0) {		/* timeout or error? */
      i = i ? errno : ETIMEDOUT;/* determine error code */
      close (sock);		/* flush socket */
      errno = i;		/* return error code */
      sprintf (tmp,"Connection failed to %.80s,%lu: %s",hst,port,
	       strerror (errno));
      return -1;
    }
  }
  return sock;			/* return the socket */
}
  
/* TCP/IP authenticated open
 * Accepts: host name
 *	    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;			/* disabled */
}

/* TCP/IP receive line
 * Accepts: TCP/IP stream
 * Returns: text line string or NIL if failure
 */

char *tcp_getline (TCPSTREAM *stream)
{
  int n,m;
  char *st,*ret,*stp;
  char c = '\0';
  char d;
				/* make sure have data */
  if (!tcp_getdata (stream)) return NIL;
  st = stream->iptr;		/* save start of string */
  n = 0;			/* init string count */
  while (stream->ictr--) {	/* look for end of line */
    d = *stream->iptr++;	/* slurp another character */
    if ((c == '\015') && (d == '\012')) {
      ret = (char *) fs_get (n--);
      memcpy (ret,st,n);	/* copy into a free storage string */
      ret[n] = '\0';		/* tie off string with null */
      return ret;
    }
    n++;			/* count another character searched */
    c = d;			/* remember previous character */
  }
				/* copy partial string from buffer */
  memcpy ((ret = stp = (char *) fs_get (n)),st,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[n - 1] = '\0';		/* tie off string with null */
  }
				/* else recurse to get remainder */
  else if (st = tcp_getline (stream)) {
    ret = (char *) fs_get (n + 1 + (m = strlen (st)));
    memcpy (ret,stp,n);		/* copy first part */
    memcpy (ret + n,st,m);	/* and second part */
    fs_give ((void **) &stp);	/* flush first part */
    fs_give ((void **) &st);	/* flush second part */
    ret[n + m] = '\0';		/* tie off string with null */
  }
  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 < 0) 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,efds;
    struct timeval tmo;
    time_t 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);
      time_t now = tl;
      int ti = ttmo_read ? now + ttmo_read : 0;
      if (tcpdebug) mm_log ("Reading TCP buffer",TCPDEBUG);
      tmo.tv_usec = 0;
      FD_ZERO (&fds);		/* initialize selection vector */
      FD_ZERO (&efds);		/* handle errors too */
      FD_SET (stream->tcpsi,&fds);
      FD_SET (stream->tcpsi,&efds);
      errno = NIL;		/* block and read */
      do {			/* block under timeout */
	tmo.tv_sec = ti ? ti - now : 0;
	i = select (stream->tcpsi+1,&fds,0,&efds,ti ? &tmo : 0);
	now = time (0);		/* fake timeout if interrupt & time expired */
	if ((i < 0) && (errno == EINTR) && ti && (ti <= now)) i = 0;
      } while ((i < 0) && (errno == EINTR));
      if (i > 0) {		/* select says there's data to read? */
	while (((i = read (stream->tcpsi,s,(int) min (maxposint,size))) < 0) &&
	       (errno == EINTR));
	if (i < 1) return tcp_abort (stream);
	s += i;			/* point at new place to write */
	size -= i;		/* reduce byte count */
	if (tcpdebug) mm_log ("Successfully read TCP buffer",TCPDEBUG);
      }
      else if (i || !tmoh || !(*tmoh) (now - t,now - tl))
	return tcp_abort (stream);
    }
    (*bn) (BLOCK_NONE,NIL);
  }
  *s = '\0';			/* tie off string */
  return T;
}