path: root/libguile/socket.c

/*	Copyright (C) 1996,1997,1998 Free Software Foundation, Inc.
 * 
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this software; see the file COPYING.  If not, write to
 * the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
 * Boston, MA 02111-1307 USA
 *
 * As a special exception, the Free Software Foundation gives permission
 * for additional uses of the text contained in its release of GUILE.
 *
 * The exception is that, if you link the GUILE library with other files
 * to produce an executable, this does not by itself cause the
 * resulting executable to be covered by the GNU General Public License.
 * Your use of that executable is in no way restricted on account of
 * linking the GUILE library code into it.
 *
 * This exception does not however invalidate any other reasons why
 * the executable file might be covered by the GNU General Public License.
 *
 * This exception applies only to the code released by the
 * Free Software Foundation under the name GUILE.  If you copy
 * code from other Free Software Foundation releases into a copy of
 * GUILE, as the General Public License permits, the exception does
 * not apply to the code that you add in this way.  To avoid misleading
 * anyone as to the status of such modified files, you must delete
 * this exception notice from them.
 *
 * If you write modifications of your own for GUILE, it is your choice
 * whether to permit this exception to apply to your modifications.
 * If you do not wish that, delete this exception notice.  */

/* Software engineering face-lift by Greg J. Badros, 11-Dec-1999,
   gjb@cs.washington.edu, http://www.cs.washington.edu/homes/gjb */



#include <stdio.h>

#include "_scm.h"
#include "unif.h"
#include "feature.h"
#include "fports.h"

#include "scm_validate.h"
#include "socket.h"

#ifdef HAVE_STRING_H
#include <string.h>
#endif
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#include <sys/types.h>
#include <sys/socket.h>
#ifdef HAVE_UNIX_DOMAIN_SOCKETS
#include <sys/un.h>
#endif
#include <netinet/in.h>
#include <netdb.h>
#include <arpa/inet.h>



SCM_DEFINE (scm_htons, "htons", 1, 0, 0, 
            (SCM in),
"Returns a new integer from @var{value} by converting from host to
network order. @var{value} must be within the range of a C unsigned
short integer.")
#define FUNC_NAME s_scm_htons
{
  unsigned short c_in;

  SCM_VALIDATE_INUM_COPY(1,in,c_in);
  if (c_in != SCM_INUM (in))
    SCM_OUT_OF_RANGE (1,in);

  return SCM_MAKINUM (htons (c_in));
}
#undef FUNC_NAME

SCM_DEFINE (scm_ntohs, "ntohs", 1, 0, 0, 
            (SCM in),
"Returns a new integer from @var{value} by converting from network to
host order.  @var{value} must be within the range of a C unsigned short
integer.")
#define FUNC_NAME s_scm_ntohs
{
  unsigned short c_in;

  SCM_VALIDATE_INUM_COPY(1,in,c_in);
  if (c_in != SCM_INUM (in))
    SCM_OUT_OF_RANGE (1,in);

  return SCM_MAKINUM (ntohs (c_in));
}
#undef FUNC_NAME

SCM_DEFINE (scm_htonl, "htonl", 1, 0, 0, 
            (SCM in),
"Returns a new integer from @var{value} by converting from host to
network order. @var{value} must be within the range of a C unsigned
long integer.")
#define FUNC_NAME s_scm_htonl
{
  unsigned long c_in = SCM_NUM2ULONG (1,in);
  return scm_ulong2num (htonl (c_in));
}
#undef FUNC_NAME

SCM_DEFINE (scm_ntohl, "ntohl", 1, 0, 0, 
            (SCM in),
"Returns a new integer from @var{value} by converting from network to
host order. @var{value} must be within the range of a C unsigned
long integer.")
#define FUNC_NAME s_scm_ntohl
{
  unsigned long c_in = SCM_NUM2ULONG (1,in);
  return scm_ulong2num (ntohl (c_in));
}
#undef FUNC_NAME

SCM_SYMBOL (sym_socket, "socket");

static SCM
scm_sock_fd_to_port (int fd, const char *proc)
{
  SCM result;
  if (fd == -1)
    scm_syserror (proc);
  result = scm_fdes_to_port (fd, "r+0", sym_socket);
  return result;
}


#define SCM_SOCK_FD_TO_PORT(fd) (scm_sock_fd_to_port((fd),FUNC_NAME))

SCM_DEFINE (scm_socket, "socket", 3, 0, 0,
            (SCM family, SCM style, SCM proto),
"Returns a new socket port of the type specified by @var{family}, @var{style}
and @var{protocol}.  All three parameters are integers.  Typical values
for @var{family} are the values of @code{AF_UNIX}
and @code{AF_INET}.  Typical values for @var{style} are
the values of @code{SOCK_STREAM}, @code{SOCK_DGRAM} and @code{SOCK_RAW}.

@var{protocol} can be obtained from a protocol name using
@code{getprotobyname}.  A value of
zero specifies the default protocol, which is usually right.

A single socket port cannot by used for communication until
it has been connected to another socket.")
#define FUNC_NAME s_scm_socket
{
  int fd;
  SCM result;

  SCM_VALIDATE_INUM(1,family);
  SCM_VALIDATE_INUM(2,style);
  SCM_VALIDATE_INUM(3,proto);
  fd = socket (SCM_INUM (family), SCM_INUM (style), SCM_INUM (proto));
  result = SCM_SOCK_FD_TO_PORT (fd);
  return result;
}
#undef FUNC_NAME



#ifdef HAVE_SOCKETPAIR
SCM_DEFINE (scm_socketpair, "socketpair", 3, 0, 0,
            (SCM family, SCM style, SCM proto),
"Returns a pair of connected (but unnamed) socket ports of the type specified
by @var{family}, @var{style} and @var{protocol}.
Many systems support only
socket pairs of the @code{AF_UNIX} family.  Zero is likely to be
the only meaningful value for @var{protocol}.")
#define FUNC_NAME s_scm_socketpair
{
  int fam;
  int fd[2];
  SCM a;
  SCM b;

  SCM_VALIDATE_INUM(1,family);
  SCM_VALIDATE_INUM(2,style);
  SCM_VALIDATE_INUM(3,proto);

  fam = SCM_INUM (family);

  if (socketpair (fam, SCM_INUM (style), SCM_INUM (proto), fd) == -1)
    SCM_SYSERROR;

  a = SCM_SOCK_FD_TO_PORT(fd[0]);
  b = SCM_SOCK_FD_TO_PORT(fd[1]);
  return scm_cons (a, b);
}
#undef FUNC_NAME
#endif

SCM_DEFINE (scm_getsockopt, "getsockopt", 3, 0, 0,
            (SCM sock, SCM level, SCM optname),
"Returns the value of a particular socket option for the socket
port @var{socket}.  @var{level} is an integer code for type of option
being requested, e.g., @code{SOL_SOCKET} for socket-level options.
@var{optname} is an
integer code for the option required and should be specified using one of
the symbols @code{SO_DEBUG}, @code{SO_REUSEADDR} etc.

The returned value is typically an integer but @code{SO_LINGER} returns a
pair of integers.")
#define FUNC_NAME s_scm_getsockopt
{
  int fd;
  int optlen;
#ifdef HAVE_STRUCT_LINGER
  char optval[sizeof (struct linger)];
#else
  char optval[sizeof (scm_sizet)];
#endif
  int ilevel;
  int ioptname;

#ifdef HAVE_STRUCT_LINGER
  optlen = (int) sizeof (struct linger);
#else
  optlen = (int) sizeof (scm_sizet);
#endif

  sock = SCM_COERCE_OUTPORT (sock);
  SCM_VALIDATE_OPFPORT(1,sock);
  SCM_VALIDATE_INUM_COPY(2,level,ilevel);
  SCM_VALIDATE_INUM_COPY(3,optname,ioptname);

  fd = SCM_FPORT_FDES (sock);
  if (getsockopt (fd, ilevel, ioptname, (void *) optval, &optlen) == -1)
    SCM_SYSERROR;

#ifdef SO_LINGER
  if (ilevel == SOL_SOCKET && ioptname == SO_LINGER)
    {
#ifdef HAVE_STRUCT_LINGER
      struct linger *ling = (struct linger *) optval;
      return scm_cons (SCM_MAKINUM (ling->l_onoff),
		       SCM_MAKINUM (ling->l_linger));
#else
      scm_sizet *ling = (scm_sizet *) optval;
      return scm_cons (SCM_MAKINUM (*ling),
		       SCM_MAKINUM (0));
#endif
    }
#endif
#ifdef SO_SNDBUF
  if (ilevel == SOL_SOCKET && ioptname == SO_SNDBUF)
    {
      scm_sizet *bufsize = (scm_sizet *) optval;
      return SCM_MAKINUM (*bufsize);
    }
#endif
#ifdef SO_RCVBUF
  if (ilevel == SOL_SOCKET && ioptname == SO_RCVBUF)
    {
      scm_sizet *bufsize = (scm_sizet *) optval;
      return SCM_MAKINUM (*bufsize);
    }
#endif
  return SCM_MAKINUM (*(int *) optval);
}
#undef FUNC_NAME

SCM_DEFINE (scm_setsockopt, "setsockopt", 4, 0, 0,
            (SCM sock, SCM level, SCM optname, SCM value),
"Sets the value of a particular socket option for the socket
port @var{socket}.  @var{level} is an integer code for type of option
being set, e.g., @code{SOL_SOCKET} for socket-level options.
@var{optname} is an
integer code for the option to set and should be specified using one of
the symbols @code{SO_DEBUG}, @code{SO_REUSEADDR} etc.
@var{value} is the value to which the option should be set.  For
most options this must be an integer, but for @code{SO_LINGER} it must
be a pair.

The return value is unspecified.")
#define FUNC_NAME s_scm_setsockopt
{
  int fd;
  int optlen;
#ifdef HAVE_STRUCT_LINGER
  char optval[sizeof (struct linger)]; /* Biggest option :-(  */
#else
  char optval[sizeof (scm_sizet)];
#endif
  int ilevel, ioptname;
  sock = SCM_COERCE_OUTPORT (sock);
  SCM_VALIDATE_OPFPORT(1,sock);
  SCM_VALIDATE_INUM_COPY(2,level,ilevel);
  SCM_VALIDATE_INUM_COPY(3,optname,ioptname);
  fd = SCM_FPORT_FDES (sock);
  if (0);
#ifdef SO_LINGER
  else if (ilevel == SOL_SOCKET && ioptname == SO_LINGER)
    {
#ifdef HAVE_STRUCT_LINGER
      struct linger ling;
      SCM_ASSERT (SCM_CONSP (value)
		  && SCM_INUMP (SCM_CAR (value))
		  &&  SCM_INUMP (SCM_CDR (value)),
		  value, SCM_ARG4, FUNC_NAME);
      ling.l_onoff = SCM_INUM (SCM_CAR (value));
      ling.l_linger = SCM_INUM (SCM_CDR (value));
      optlen = (int) sizeof (struct linger);
      memcpy (optval, (void *) &ling, optlen);
#else
      scm_sizet ling;
      SCM_ASSERT (SCM_CONSP (value)
		  && SCM_INUMP (SCM_CAR (value))
		  &&  SCM_INUMP (SCM_CDR (value)),
		  value, SCM_ARG4, FUNC_NAME);
      ling = SCM_INUM (SCM_CAR (value));
      optlen = (int) sizeof (scm_sizet);
      (*(scm_sizet *) optval) = (scm_sizet) SCM_INUM (value);
#endif
    }
#endif
#ifdef SO_SNDBUF
  else if (ilevel == SOL_SOCKET && ioptname == SO_SNDBUF)
    {
      SCM_VALIDATE_INUM(4,value);
      optlen = (int) sizeof (scm_sizet);
      (*(scm_sizet *) optval) = (scm_sizet) SCM_INUM (value);
    }
#endif
#ifdef SO_RCVBUF
  else if (ilevel == SOL_SOCKET && ioptname == SO_RCVBUF)
    {
      SCM_VALIDATE_INUM(4,value);
      optlen = (int) sizeof (scm_sizet);
      (*(scm_sizet *) optval) = (scm_sizet) SCM_INUM (value);
    }
#endif
  else
    {
      /* Most options just take an int.  */
      SCM_VALIDATE_INUM(4,value);
      optlen = (int) sizeof (int);
      (*(int *) optval) = (int) SCM_INUM (value);
    }
  if (setsockopt (fd, ilevel, ioptname, (void *) optval, optlen) == -1)
    SCM_SYSERROR;
  return SCM_UNSPECIFIED;
}
#undef FUNC_NAME

SCM_DEFINE (scm_shutdown, "shutdown", 2, 0, 0,
          (SCM sock, SCM how),
"Sockets can be closed simply by using @code{close-port}. The
@code{shutdown} procedure allows reception or tranmission on a
connection to be shut down individually, according to the parameter
@var{how}:

@table @asis
@item 0
Stop receiving data for this socket.  If further data arrives,  reject it.
@item 1
Stop trying to transmit data from this socket.  Discard any
data waiting to be sent.  Stop looking for acknowledgement of
data already sent; don't retransmit it if it is lost.
@item 2
Stop both reception and transmission.
@end table

The return value is unspecified.")
#define FUNC_NAME s_scm_shutdown
{
  int fd;
  sock = SCM_COERCE_OUTPORT (sock);
  SCM_VALIDATE_OPFPORT(1,sock);
  SCM_VALIDATE_INUM(2,how);
  SCM_ASSERT_RANGE(2,how,0 <= SCM_INUM (how) && 2 >= SCM_INUM (how));
  fd = SCM_FPORT_FDES (sock);
  if (shutdown (fd, SCM_INUM (how)) == -1)
    SCM_SYSERROR;
  return SCM_UNSPECIFIED;
}
#undef FUNC_NAME

/* convert fam/address/args into a sockaddr of the appropriate type.
   args is modified by removing the arguments actually used.
   which_arg and proc are used when reporting errors:
   which_arg is the position of address in the original argument list.
   proc is the name of the original procedure.
   size returns the size of the structure allocated.  */


static struct sockaddr *
scm_fill_sockaddr (int fam,SCM address,SCM *args,int which_arg,const char *proc,scm_sizet *size)
{
  switch (fam)
    {
    case AF_INET:
      {
	SCM isport;
	struct sockaddr_in *soka;

	soka = (struct sockaddr_in *)
	  scm_must_malloc (sizeof (struct sockaddr_in), proc);
	/* e.g., for BSDs which don't like invalid sin_len.  */
	memset (soka, 0, sizeof (struct sockaddr_in));
	soka->sin_family = AF_INET;
	soka->sin_addr.s_addr =
	  htonl (scm_num2ulong (address, (char *) which_arg, proc));
	SCM_ASSERT (SCM_CONSP (*args), *args, 
		    which_arg + 1, proc);
	isport = SCM_CAR (*args);
	*args = SCM_CDR (*args);
	SCM_ASSERT (SCM_INUMP (isport), isport, which_arg + 1, proc);
	soka->sin_port = htons (SCM_INUM (isport));
	*size = sizeof (struct sockaddr_in);
	return (struct sockaddr *) soka;
      }
#ifdef HAVE_UNIX_DOMAIN_SOCKETS
    case AF_UNIX:
      {
	struct sockaddr_un *soka;

	soka = (struct sockaddr_un *)
	  scm_must_malloc (sizeof (struct sockaddr_un), proc);
	memset (soka, 0, sizeof (struct sockaddr_un));
	soka->sun_family = AF_UNIX;
	SCM_ASSERT (SCM_ROSTRINGP (address), address,
		    which_arg, proc);
	memcpy (soka->sun_path, SCM_ROCHARS (address),
		1 + SCM_ROLENGTH (address));
	*size = sizeof (struct sockaddr_un);
	return (struct sockaddr *) soka;
      }
#endif
    default:
      scm_out_of_range (proc, SCM_MAKINUM (fam));
    }
}
  
SCM_DEFINE (scm_connect, "connect", 3, 0, 1,
            (SCM sock, SCM fam, SCM address, SCM args),
"Initiates a connection from @var{socket} to the address
specified by @var{address} and possibly @var{arg @dots{}}.  The format
required for @var{address}
and @var{arg} @dots{} depends on the family of the socket.

For a socket of family @code{AF_UNIX},
only @code{address} is specified and must be a string with the
filename where the socket is to be created.

For a socket of family @code{AF_INET},
@code{address} must be an integer Internet host address and @var{arg} @dots{}
must be a single integer port number.

The return value is unspecified.")
#define FUNC_NAME s_scm_connect
{
  int fd;
  struct sockaddr *soka;
  scm_sizet size;

  sock = SCM_COERCE_OUTPORT (sock);
  SCM_VALIDATE_OPFPORT(1,sock);
  SCM_VALIDATE_INUM(2,fam);
  fd = SCM_FPORT_FDES (sock);
  soka = scm_fill_sockaddr (SCM_INUM (fam), address, &args, 3, FUNC_NAME, &size);
  if (connect (fd, soka, size) == -1)
    SCM_SYSERROR;
  scm_must_free ((char *) soka);
  return SCM_UNSPECIFIED;
}
#undef FUNC_NAME

SCM_DEFINE (scm_bind, "bind", 3, 0, 1,
            (SCM sock, SCM fam, SCM address, SCM args),
"Assigns an address to the socket port @var{socket}.
Generally this only needs to be done for server sockets,
so they know where to look for incoming connections.  A socket
without an address will be assigned one automatically when it
starts communicating.

The format of @var{address} and @var{ARG} @dots{} depends on the family
of the socket.

For a socket of family @code{AF_UNIX}, only @var{address}
is specified and must 
be a string with the filename where the socket is to be created.

For a socket of family @code{AF_INET}, @var{address} must be an integer
Internet host address and @var{arg} @dots{} must be a single integer
port number.

The values of the following variables can also be used for @var{address}:

@defvar INADDR_ANY
Allow connections from any address.
@end defvar

@defvar INADDR_LOOPBACK
The address of the local host using the loopback device.
@end defvar

@defvar INADDR_BROADCAST
The broadcast address on the local network.
@end defvar

@defvar INADDR_NONE
No address.
@end defvar

The return value is unspecified.")
#define FUNC_NAME s_scm_bind
{
  int rv;
  struct sockaddr *soka;
  scm_sizet size;
  int fd;

  sock = SCM_COERCE_OUTPORT (sock);
  SCM_VALIDATE_OPFPORT(1,sock);
  SCM_VALIDATE_INUM(2,fam);
  soka = scm_fill_sockaddr (SCM_INUM (fam), address, &args, 3, FUNC_NAME, &size);
  fd = SCM_FPORT_FDES (sock);
  rv = bind (fd, soka, size);
  if (rv == -1)
    SCM_SYSERROR;
  scm_must_free ((char *) soka);
  return SCM_UNSPECIFIED;
}
#undef FUNC_NAME

SCM_DEFINE (scm_listen, "listen", 2, 0, 0,
            (SCM sock, SCM backlog),
"This procedure enables @var{socket} to accept connection
requests.  @var{backlog} is an integer specifying
the maximum length of the queue for pending connections.
If the queue fills, new clients will fail to connect until the
server calls @code{accept} to accept a connection from the queue.

The return value is unspecified.")
#define FUNC_NAME s_scm_listen
{
  int fd;
  sock = SCM_COERCE_OUTPORT (sock);
  SCM_VALIDATE_OPFPORT(1,sock);
  SCM_VALIDATE_INUM(2,backlog);
  fd = SCM_FPORT_FDES (sock);
  if (listen (fd, SCM_INUM (backlog)) == -1)
    SCM_SYSERROR;
  return SCM_UNSPECIFIED;
}
#undef FUNC_NAME

/* Put the components of a sockaddr into a new SCM vector.  */

static SCM
scm_addr_vector (struct sockaddr *address,const char *proc)
{
  short int fam = address->sa_family;
  SCM result;
  SCM *ve;
#ifdef HAVE_UNIX_DOMAIN_SOCKETS
  if (fam == AF_UNIX)
    {
      struct sockaddr_un *nad = (struct sockaddr_un *) address;
      result = scm_make_vector (SCM_MAKINUM (2), SCM_UNSPECIFIED);
      ve = SCM_VELTS (result);
      ve[0] = scm_ulong2num ((unsigned long) fam);
      ve[1] = scm_makfromstr (nad->sun_path,
			      (scm_sizet) strlen (nad->sun_path), 0);
    }
  else 
#endif
  if (fam == AF_INET)
    {
      struct sockaddr_in *nad = (struct sockaddr_in *) address;
      result = scm_make_vector (SCM_MAKINUM (3), SCM_UNSPECIFIED);
      ve = SCM_VELTS (result);
      ve[0] = scm_ulong2num ((unsigned long) fam);
      ve[1] = scm_ulong2num (ntohl (nad->sin_addr.s_addr));
      ve[2] = scm_ulong2num ((unsigned long) ntohs (nad->sin_port));
    }
  else
    scm_misc_error (proc, "Unrecognised address family: %s",
		    scm_listify (SCM_MAKINUM (fam), SCM_UNDEFINED));

  return result;
}

/* Allocate a buffer large enough to hold any sockaddr type.  */
static char *scm_addr_buffer;
static int scm_addr_buffer_size;

static void
scm_init_addr_buffer (void)
{
  scm_addr_buffer_size =
#ifdef HAVE_UNIX_DOMAIN_SOCKETS
  (int) sizeof (struct sockaddr_un)
#else
  0
#endif
  ;
  if (sizeof (struct sockaddr_in) > scm_addr_buffer_size)
    scm_addr_buffer_size = (int) sizeof (struct sockaddr_in);
  scm_addr_buffer = scm_must_malloc (scm_addr_buffer_size, "address buffer");
}

SCM_DEFINE (scm_accept, "accept", 1, 0, 0, 
            (SCM sock),
"Accepts a connection on a bound, listening socket @var{socket}.  If there
are no pending connections in the queue, it waits until
one is available unless the non-blocking option has been set on the
socket.

The return value is a
pair in which the CAR is a new socket port for the connection and
the CDR is an object with address information about the client which
initiated the connection.

If the address is not available then the CDR will be an empty vector.

@var{socket} does not become part of the
connection and will continue to accept new requests.")
#define FUNC_NAME s_scm_accept
{
  int fd;
  int newfd;
  SCM address;
  SCM newsock;

  int tmp_size;
  sock = SCM_COERCE_OUTPORT (sock);
  SCM_VALIDATE_OPFPORT(1,sock);
  fd = SCM_FPORT_FDES (sock);
  tmp_size = scm_addr_buffer_size;
  newfd = accept (fd, (struct sockaddr *) scm_addr_buffer, &tmp_size);
  newsock = scm_sock_fd_to_port (newfd, FUNC_NAME);
  if (tmp_size > 0)
    address = scm_addr_vector ((struct sockaddr *) scm_addr_buffer, FUNC_NAME);
  else
    address = SCM_BOOL_F;
  
  return scm_cons (newsock, address);
}
#undef FUNC_NAME

SCM_DEFINE (scm_getsockname, "getsockname", 1, 0, 0, 
            (SCM sock),
"Returns the address of @var{socket}, in the same form as the object
returned by @code{accept}.  On many systems the address of a socket
in the @code{AF_FILE} namespace cannot be read.")
#define FUNC_NAME s_scm_getsockname
{
  int tmp_size;
  int fd;
  SCM result;
  sock = SCM_COERCE_OUTPORT (sock);
  SCM_VALIDATE_OPFPORT(1,sock);
  fd = SCM_FPORT_FDES (sock);
  tmp_size = scm_addr_buffer_size;
  if (getsockname (fd, (struct sockaddr *) scm_addr_buffer, &tmp_size) == -1)
    SCM_SYSERROR;
  if (tmp_size > 0)
    result = scm_addr_vector ((struct sockaddr *) scm_addr_buffer, FUNC_NAME);
  else
    result = SCM_BOOL_F;
  return result;
}
#undef FUNC_NAME

SCM_DEFINE (scm_getpeername, "getpeername", 1, 0, 0, 
            (SCM sock),
"Returns the address of the socket that the socket @var{socket} is connected to,
in the same form as the object
returned by @code{accept}.  On many systems the address of a socket
in the @code{AF_FILE} namespace cannot be read.")
#define FUNC_NAME s_scm_getpeername
{
  int tmp_size;
  int fd;
  SCM result;
  sock = SCM_COERCE_OUTPORT (sock);
  SCM_VALIDATE_OPFPORT(1,sock);
  fd = SCM_FPORT_FDES (sock);
  tmp_size = scm_addr_buffer_size;
  if (getpeername (fd, (struct sockaddr *) scm_addr_buffer, &tmp_size) == -1)
    SCM_SYSERROR;
  if (tmp_size > 0)
    result = scm_addr_vector ((struct sockaddr *) scm_addr_buffer, FUNC_NAME);
  else
    result = SCM_BOOL_F;
  return result;
}
#undef FUNC_NAME

SCM_DEFINE (scm_recv, "recv!", 2, 1, 0,
            (SCM sock, SCM buf, SCM flags),
"Receives data from the socket port @var{socket}.  @var{socket} must already
be bound to the address from which data is to be received.
@var{buf} is a string into which
the data will be written.  The size of @var{buf} limits the amount of
data which can be received: in the case of packet
protocols, if a packet larger than this limit is encountered then some data
will be irrevocably lost.

The optional @var{flags} argument is a value or
bitwise OR of MSG_OOB, MSG_PEEK, MSG_DONTROUTE etc.

The value returned is the number of bytes read from the socket.

Note that the data is read directly from the socket file descriptor:
any unread buffered port data is ignored.")
#define FUNC_NAME s_scm_recv
{
  int rv;
  int fd;
  int flg;

  SCM_VALIDATE_OPFPORT(1,sock);
  SCM_VALIDATE_STRING(2,buf);
  SCM_VALIDATE_INUM_DEF_COPY(3,flags,0,flg);
  fd = SCM_FPORT_FDES (sock);

  SCM_SYSCALL (rv = recv (fd, SCM_CHARS (buf), SCM_LENGTH (buf), flg));
  if (rv == -1)
    SCM_SYSERROR;

  return SCM_MAKINUM (rv);
}
#undef FUNC_NAME

SCM_DEFINE (scm_send, "send", 2, 1, 0,
            (SCM sock, SCM message, SCM flags),
"Transmits the string @var{message} on the socket port @var{socket}. 
@var{socket} must already be bound to a destination address.  The
value returned is the number of bytes transmitted -- it's possible for
this to be less than the length of @var{message} if the socket is
set to be non-blocking.  The optional @var{flags} argument is a value or
bitwise OR of MSG_OOB, MSG_PEEK, MSG_DONTROUTE etc.

Note that the data is written directly to the socket file descriptor:
any unflushed buffered port data is ignored.")
#define FUNC_NAME s_scm_send
{
  int rv;
  int fd;
  int flg;

  sock = SCM_COERCE_OUTPORT (sock);
  SCM_VALIDATE_OPFPORT(1,sock);
  SCM_VALIDATE_ROSTRING(2,message);
  SCM_VALIDATE_INUM_DEF_COPY(3,flags,0,flg);
  fd = SCM_FPORT_FDES (sock);

  SCM_SYSCALL (rv = send (fd, SCM_ROCHARS (message), SCM_ROLENGTH (message), flg));
  if (rv == -1)
    SCM_SYSERROR;
  return SCM_MAKINUM (rv);
}
#undef FUNC_NAME

SCM_DEFINE (scm_recvfrom, "recvfrom!", 2, 3, 0,
            (SCM sock, SCM buf, SCM flags, SCM start, SCM end),
"Returns data from the socket port @var{socket} and also information about
where the data was received from.  @var{socket} must already
be bound to the address from which data is to be received.
@code{buf}, is a string into which
the data will be written.  The size of @var{buf} limits the amount of
data which can be received: in the case of packet
protocols, if a packet larger than this limit is encountered then some data
will be irrevocably lost.

The optional @var{flags} argument is a value or
bitwise OR of MSG_OOB, MSG_PEEK, MSG_DONTROUTE etc.

The value returned is a pair: the CAR is the number of bytes read from
the socket and the CDR an address object in the same form as returned by
@code{accept}.

The @var{start} and @var{end} arguments specify a substring of @var{buf}
to which the data should be written.

Note that the data is read directly from the socket file descriptor:
any unread buffered port data is ignored.")
#define FUNC_NAME s_scm_recvfrom
{
  int rv;
  int fd;
  int flg;
  int offset = 0;
  int cend;
  int tmp_size;
  SCM address;

  SCM_VALIDATE_OPFPORT(1,sock);
  SCM_VALIDATE_STRING(2,buf);
  cend = SCM_LENGTH (buf);
  
  if (SCM_UNBNDP (flags))
    flg = 0;
  else
    {
      flg = SCM_NUM2ULONG (3,flags);

      if (!SCM_UNBNDP (start))
	{
	  offset = (int) SCM_NUM2LONG (4,start);
	  
	  if (offset < 0 || offset >= cend)
	    SCM_OUT_OF_RANGE (4, start);

	  if (!SCM_UNBNDP (end))
	    {
	      int tend = (int) SCM_NUM2LONG (5,end);
      
	      if (tend <= offset || tend > cend)
		SCM_OUT_OF_RANGE (5, end);

	      cend = tend;
	    }
	}
    }

  fd = SCM_FPORT_FDES (sock);

  tmp_size = scm_addr_buffer_size;
  SCM_SYSCALL (rv = recvfrom (fd, SCM_CHARS (buf) + offset,
			      cend - offset, flg,
			      (struct sockaddr *) scm_addr_buffer,
			      &tmp_size));
  if (rv == -1)
    SCM_SYSERROR;
  if (tmp_size > 0)
    address = scm_addr_vector ((struct sockaddr *) scm_addr_buffer, FUNC_NAME);
  else
    address = SCM_BOOL_F;

  return scm_cons (SCM_MAKINUM (rv), address);
}
#undef FUNC_NAME

SCM_DEFINE (scm_sendto, "sendto", 4, 0, 1,
            (SCM sock, SCM message, SCM fam, SCM address, SCM args_and_flags),
"Transmits the string @var{message} on the socket port @var{socket}.  The
destination address is specified using the @var{family}, @var{address} and
@var{arg} arguments, in a similar way to the @code{connect}
procedure.  The
value returned is the number of bytes transmitted -- it's possible for
this to be less than the length of @var{message} if the socket is
set to be non-blocking.  The optional @var{flags} argument is a value or
bitwise OR of MSG_OOB, MSG_PEEK, MSG_DONTROUTE etc.

Note that the data is written directly to the socket file descriptor:
any unflushed buffered port data is ignored.")
#define FUNC_NAME s_scm_sendto
{
  int rv;
  int fd;
  int flg;
  struct sockaddr *soka;
  scm_sizet size;
  int save_err;

  sock = SCM_COERCE_OUTPORT (sock);
  SCM_VALIDATE_FPORT(1,sock);
  SCM_VALIDATE_ROSTRING(2,message);
  SCM_VALIDATE_INUM(3,fam);
  fd = SCM_FPORT_FDES (sock);
  soka = scm_fill_sockaddr (SCM_INUM (fam), address, &args_and_flags, 4,
			    FUNC_NAME, &size);
  if (SCM_NULLP (args_and_flags))
    flg = 0;
  else
    {
      SCM_VALIDATE_CONS(5,args_and_flags);
      flg = SCM_NUM2ULONG (5,SCM_CAR (args_and_flags));
    }
  SCM_SYSCALL (rv = sendto (fd, SCM_ROCHARS (message), SCM_ROLENGTH (message),
			    flg, soka, size));
  save_err = errno;
  scm_must_free ((char *) soka);
  errno = save_err;
  if (rv == -1)
    SCM_SYSERROR;
  return SCM_MAKINUM (rv);
}
#undef FUNC_NAME



void
scm_init_socket ()
{
  /* protocol families.  */
#ifdef AF_UNSPEC
  scm_sysintern ("AF_UNSPEC", SCM_MAKINUM (AF_UNSPEC));
#endif
#ifdef AF_UNIX
  scm_sysintern ("AF_UNIX", SCM_MAKINUM (AF_UNIX));
#endif
#ifdef AF_INET
  scm_sysintern ("AF_INET", SCM_MAKINUM (AF_INET));
#endif

#ifdef PF_UNSPEC
  scm_sysintern ("PF_UNSPEC", SCM_MAKINUM (PF_UNSPEC));
#endif
#ifdef PF_UNIX
  scm_sysintern ("PF_UNIX", SCM_MAKINUM (PF_UNIX));
#endif
#ifdef PF_INET
  scm_sysintern ("PF_INET", SCM_MAKINUM (PF_INET));
#endif

  /* socket types.  */
#ifdef SOCK_STREAM
  scm_sysintern ("SOCK_STREAM", SCM_MAKINUM (SOCK_STREAM));
#endif
#ifdef SOCK_DGRAM
  scm_sysintern ("SOCK_DGRAM", SCM_MAKINUM (SOCK_DGRAM));
#endif
#ifdef SOCK_RAW
  scm_sysintern ("SOCK_RAW", SCM_MAKINUM (SOCK_RAW));
#endif

  /* setsockopt level.  */
#ifdef SOL_SOCKET
  scm_sysintern ("SOL_SOCKET", SCM_MAKINUM (SOL_SOCKET));
#endif
#ifdef SOL_IP
  scm_sysintern ("SOL_IP", SCM_MAKINUM (SOL_IP));
#endif
#ifdef SOL_TCP
  scm_sysintern ("SOL_TCP", SCM_MAKINUM (SOL_TCP));
#endif
#ifdef SOL_UDP
  scm_sysintern ("SOL_UDP", SCM_MAKINUM (SOL_UDP));
#endif

  /* setsockopt names.  */
#ifdef SO_DEBUG
  scm_sysintern ("SO_DEBUG", SCM_MAKINUM (SO_DEBUG));
#endif
#ifdef SO_REUSEADDR
  scm_sysintern ("SO_REUSEADDR", SCM_MAKINUM (SO_REUSEADDR));
#endif
#ifdef SO_STYLE
  scm_sysintern ("SO_STYLE", SCM_MAKINUM (SO_STYLE));
#endif
#ifdef SO_TYPE
  scm_sysintern ("SO_TYPE", SCM_MAKINUM (SO_TYPE));
#endif
#ifdef SO_ERROR
  scm_sysintern ("SO_ERROR", SCM_MAKINUM (SO_ERROR));
#endif
#ifdef SO_DONTROUTE
  scm_sysintern ("SO_DONTROUTE", SCM_MAKINUM (SO_DONTROUTE));
#endif
#ifdef SO_BROADCAST
  scm_sysintern ("SO_BROADCAST", SCM_MAKINUM (SO_BROADCAST));
#endif
#ifdef SO_SNDBUF
  scm_sysintern ("SO_SNDBUF", SCM_MAKINUM (SO_SNDBUF));
#endif
#ifdef SO_RCVBUF
  scm_sysintern ("SO_RCVBUF", SCM_MAKINUM (SO_RCVBUF));
#endif
#ifdef SO_KEEPALIVE
  scm_sysintern ("SO_KEEPALIVE", SCM_MAKINUM (SO_KEEPALIVE));
#endif
#ifdef SO_OOBINLINE
  scm_sysintern ("SO_OOBINLINE", SCM_MAKINUM (SO_OOBINLINE));
#endif
#ifdef SO_NO_CHECK
  scm_sysintern ("SO_NO_CHECK", SCM_MAKINUM (SO_NO_CHECK));
#endif
#ifdef SO_PRIORITY
  scm_sysintern ("SO_PRIORITY", SCM_MAKINUM (SO_PRIORITY));
#endif
#ifdef SO_LINGER
  scm_sysintern ("SO_LINGER", SCM_MAKINUM (SO_LINGER));
#endif

  /* recv/send options.  */
#ifdef MSG_OOB
  scm_sysintern ("MSG_OOB", SCM_MAKINUM (MSG_OOB));
#endif
#ifdef MSG_PEEK
  scm_sysintern ("MSG_PEEK", SCM_MAKINUM (MSG_PEEK));
#endif
#ifdef MSG_DONTROUTE
  scm_sysintern ("MSG_DONTROUTE", SCM_MAKINUM (MSG_DONTROUTE));
#endif

  scm_add_feature ("socket");
  scm_init_addr_buffer ();

#include "socket.x"
}