socket.c

OpenVPN is a robust and highly flexible tunneling application that uses all of the encryption, authe

  struct sockaddr_in si;
  CLEAR (si);
  si.sin_addr.s_addr = htonl (addr);
  setenv_sockaddr (name_prefix, &si);
}

/*
 * Convert protocol names between index and ascii form.
 */

struct proto_names {
  const char *short_form;
  const char *display_form;
};

/* Indexed by PROTO_x */
static const struct proto_names proto_names[] = {
  {"udp",        "UDPv4"},
  {"tcp-server", "TCPv4_SERVER"},
  {"tcp-client", "TCPv4_CLIENT"}
};

int
ascii2proto (const char* proto_name)
{
  int i;
  ASSERT (PROTO_N == SIZE (proto_names));
  for (i = 0; i < PROTO_N; ++i)
    if (!strcmp (proto_name, proto_names[i].short_form))
      return i;
  return -1;
}

const char *
proto2ascii (int proto, bool display_form)
{
  ASSERT (PROTO_N == SIZE (proto_names));
  if (proto < 0 || proto >= PROTO_N)
    return "[unknown protocol]";
  else if (display_form)
    return proto_names[proto].display_form;
  else
    return proto_names[proto].short_form;
}

const char *
proto2ascii_all (struct gc_arena *gc)
{
  struct buffer out = alloc_buf_gc (256, gc);
  int i;

  ASSERT (PROTO_N == SIZE (proto_names));
  for (i = 0; i < PROTO_N; ++i)
    {
      if (i)
	buf_printf(&out, " ");
      buf_printf(&out, "[%s]", proto2ascii(i, false));
    }
  return BSTR (&out);
}

/*
 * Given a local proto, return local proto
 * if !remote, or compatible remote proto
 * if remote.
 *
 * This is used for options compatibility
 * checking.
 */
int
proto_remote (int proto, bool remote)
{
  ASSERT (proto >= 0 && proto < PROTO_N);
  if (remote)
    {
      if (proto == PROTO_TCPv4_SERVER)
	return PROTO_TCPv4_CLIENT;
      if (proto == PROTO_TCPv4_CLIENT)
	return PROTO_TCPv4_SERVER;
    }
  return proto;
}

/*
 * Bad incoming address lengths that differ from what
 * we expect are considered to be fatal errors.
 */
void
bad_address_length (int actual, int expected)
{
  msg (M_FATAL, "ERROR: received strange incoming packet with an address length of %d -- we only accept address lengths of %d.",
       actual,
       expected);
}

/*
 * Socket Read Routines
 */

int
link_socket_read_tcp (struct link_socket *sock,
		      struct buffer *buf)
{
  int len = 0;

  if (!sock->stream_buf.residual_fully_formed)
    {
#ifdef WIN32
      len = socket_finalize (sock->sd, &sock->reads, buf, NULL);
#else
      struct buffer frag;
      stream_buf_get_next (&sock->stream_buf, &frag);
      len = recv (sock->sd, BPTR (&frag), BLEN (&frag), MSG_NOSIGNAL);
#endif

      if (!len)
	sock->stream_reset = true;
      if (len <= 0)
	return buf->len = len;
    }

  if (sock->stream_buf.residual_fully_formed
      || stream_buf_added (&sock->stream_buf, len)) /* packet complete? */
    {
      stream_buf_get_final (&sock->stream_buf, buf);
      stream_buf_reset (&sock->stream_buf);
      return buf->len;
    }
  else
    return buf->len = 0; /* no error, but packet is still incomplete */
}

#ifndef WIN32

int
link_socket_read_udp_posix (struct link_socket *sock,
			    struct buffer *buf,
			    int maxsize,
			    struct sockaddr_in *from)
{
  socklen_t fromlen = sizeof (*from);
  CLEAR (*from);
  ASSERT (buf_safe (buf, maxsize));
  buf->len = recvfrom (sock->sd, BPTR (buf), maxsize, 0,
		       (struct sockaddr *) from, &fromlen);
  if (fromlen != sizeof (*from))
    bad_address_length (fromlen, sizeof (*from));
  return buf->len;
}

#endif

/*
 * Socket Write Routines
 */

int
link_socket_write_tcp (struct link_socket *sock,
		       struct buffer *buf,
		       struct sockaddr_in *to)
{
  packet_size_type len = BLEN (buf);
  msg (D_STREAM_DEBUG, "STREAM: WRITE %d offset=%d", (int)len, buf->offset);
  ASSERT (len <= sock->stream_buf.maxlen);
  len = htonps (len);
  ASSERT (buf_write_prepend (buf, &len, sizeof (len)));
#ifdef WIN32
  return link_socket_write_win32 (sock, buf, to);
#else
  return link_socket_write_tcp_posix (sock, buf, to);  
#endif
}

/*
 * Win32 overlapped socket I/O functions.
 */

#ifdef WIN32

int
socket_recv_queue (struct link_socket *sock, int maxsize)
{
  if (sock->reads.iostate == IOSTATE_INITIAL)
    {
      WSABUF wsabuf[1];
      int status;

      /* reset buf to its initial state */
      if (sock->info.proto == PROTO_UDPv4)
	{
	  sock->reads.buf = sock->reads.buf_init;
	}
      else if (sock->info.proto == PROTO_TCPv4_CLIENT || sock->info.proto == PROTO_TCPv4_SERVER)
	{
	  stream_buf_get_next (&sock->stream_buf, &sock->reads.buf);
	}
      else
	{
	  ASSERT (0);
	}

      /* Win32 docs say it's okay to allocate the wsabuf on the stack */
      wsabuf[0].buf = BPTR (&sock->reads.buf);
      wsabuf[0].len = maxsize ? maxsize : BLEN (&sock->reads.buf);

      /* check for buffer overflow */
      ASSERT (wsabuf[0].len <= BLEN (&sock->reads.buf));

      /* the overlapped read will signal this event on I/O completion */
      ASSERT (ResetEvent (sock->reads.overlapped.hEvent));
      sock->reads.flags = 0;

      if (sock->info.proto == PROTO_UDPv4)
	{
	  sock->reads.addr_defined = true;
	  sock->reads.addrlen = sizeof (sock->reads.addr);
	  status = WSARecvFrom(
			       sock->sd,
			       wsabuf,
			       1,
			       &sock->reads.size,
			       &sock->reads.flags,
			       (struct sockaddr *) &sock->reads.addr,
			       &sock->reads.addrlen,
			       &sock->reads.overlapped,
			       NULL);
	}
      else if (sock->info.proto == PROTO_TCPv4_CLIENT || sock->info.proto == PROTO_TCPv4_SERVER)
	{
	  sock->reads.addr_defined = false;
	  status = WSARecv(
			   sock->sd,
			   wsabuf,
			   1,
			   &sock->reads.size,
			   &sock->reads.flags,
			   &sock->reads.overlapped,
			   NULL);
	}
      else
	{
	  status = 0;
	  ASSERT (0);
	}

      if (!status) /* operation completed immediately? */
	{
	  if (sock->reads.addr_defined && sock->reads.addrlen != sizeof (sock->reads.addr))
	    bad_address_length (sock->reads.addrlen, sizeof (sock->reads.addr));

	  sock->reads.iostate = IOSTATE_IMMEDIATE_RETURN;

	  /* since we got an immediate return, we must signal the event object ourselves */
	  ASSERT (SetEvent (sock->reads.overlapped.hEvent));
	  sock->reads.status = 0;

	  msg (D_WIN32_IO, "WIN32 I/O: Socket Receive immediate return [%d,%d]",
	       (int) wsabuf[0].len,
	       (int) sock->reads.size);	       
	}
      else
	{
	  status = WSAGetLastError (); 
	  if (status == WSA_IO_PENDING) /* operation queued? */
	    {
	      sock->reads.iostate = IOSTATE_QUEUED;
	      sock->reads.status = status;
	      msg (D_WIN32_IO, "WIN32 I/O: Socket Receive queued [%d]",
		   (int) wsabuf[0].len);
	    }
	  else /* error occurred */
	    {
	      struct gc_arena gc = gc_new ();
	      ASSERT (SetEvent (sock->reads.overlapped.hEvent));
	      sock->reads.iostate = IOSTATE_IMMEDIATE_RETURN;
	      sock->reads.status = status;
	      msg (D_WIN32_IO, "WIN32 I/O: Socket Receive error [%d]: %s",
		   (int) wsabuf[0].len,
		   strerror_win32 (status, &gc));
	      gc_free (&gc);
	    }
	}
    }
  return sock->reads.iostate;
}

int
socket_send_queue (struct link_socket *sock, struct buffer *buf, const struct sockaddr_in *to)
{
  if (sock->writes.iostate == IOSTATE_INITIAL)
    {
      WSABUF wsabuf[1];
      int status;
 
      /* make a private copy of buf */
      sock->writes.buf = sock->writes.buf_init;
      sock->writes.buf.len = 0;
      ASSERT (buf_copy (&sock->writes.buf, buf));

      /* Win32 docs say it's okay to allocate the wsabuf on the stack */
      wsabuf[0].buf = BPTR (&sock->writes.buf);
      wsabuf[0].len = BLEN (&sock->writes.buf);

      /* the overlapped write will signal this event on I/O completion */
      ASSERT (ResetEvent (sock->writes.overlapped.hEvent));
      sock->writes.flags = 0;

      if (sock->info.proto == PROTO_UDPv4)
	{
	  /* set destination address for UDP writes */
	  sock->writes.addr_defined = true;
	  sock->writes.addr = *to;
	  sock->writes.addrlen = sizeof (sock->writes.addr);

	  status = WSASendTo(
			       sock->sd,
			       wsabuf,
			       1,
			       &sock->writes.size,
			       sock->writes.flags,
			       (struct sockaddr *) &sock->writes.addr,
			       sock->writes.addrlen,
			       &sock->writes.overlapped,
			       NULL);
	}
      else if (sock->info.proto == PROTO_TCPv4_CLIENT || sock->info.proto == PROTO_TCPv4_SERVER)
	{
	  /* destination address for TCP writes was established on connection initiation */
	  sock->writes.addr_defined = false;

	  status = WSASend(
			   sock->sd,
			   wsabuf,
			   1,
			   &sock->writes.size,
			   sock->writes.flags,
			   &sock->writes.overlapped,
			   NULL);
	}
      else 
	{
	  status = 0;
	  ASSERT (0);
	}

      if (!status) /* operation completed immediately? */
	{
	  sock->writes.iostate = IOSTATE_IMMEDIATE_RETURN;

	  /* since we got an immediate return, we must signal the event object ourselves */
	  ASSERT (SetEvent (sock->writes.overlapped.hEvent));

	  sock->writes.status = 0;

	  msg (D_WIN32_IO, "WIN32 I/O: Socket Send immediate return [%d,%d]",
	       (int) wsabuf[0].len,
	       (int) sock->writes.size);	       
	}
      else
	{
	  status = WSAGetLastError (); 
	  if (status == WSA_IO_PENDING) /* operation queued? */
	    {
	      sock->writes.iostate = IOSTATE_QUEUED;
	      sock->writes.status = status;
	      msg (D_WIN32_IO, "WIN32 I/O: Socket Send queued [%d]",
		   (int) wsabuf[0].len);
	    }
	  else /* error occurred */
	    {
	      struct gc_arena gc = gc_new ();
	      ASSERT (SetEvent (sock->writes.overlapped.hEvent));
	      sock->writes.iostate = IOSTATE_IMMEDIATE_RETURN;
	      sock->writes.status = status;

	      msg (D_WIN32_IO, "WIN32 I/O: Socket Send error [%d]: %s",
		   (int) wsabuf[0].len,
		   strerror_win32 (status, &gc));

	      gc_free (&gc);
	    }
	}
    }
  return sock->writes.iostate;
}

int
socket_finalize (
		 SOCKET s,
		 struct overlapped_io *io,
		 struct buffer *buf,
		 struct sockaddr_in *from)
{
  int ret = -1;
  BOOL status;

  switch (io->iostate)
    {
    case IOSTATE_QUEUED:
      status = WSAGetOverlappedResult(
				      s,
				      &io->overlapped,
				      &io->size,
				      FALSE,
				      &io->flags
				      );
      if (status)
	{
	  /* successful return for a queued operation */
	  if (buf)
	    *buf = io->buf;
	  ret = io->size;
	  io->iostate = IOSTATE_INITIAL;
	  ASSERT (ResetEvent (io->overlapped.hEvent));

	  msg (D_WIN32_IO, "WIN32 I/O: Socket Completion success [%d]", ret);
	}
      else
	{
	  /* error during a queued operation */
	  ret = -1;
	  if (WSAGetLastError() != WSA_IO_INCOMPLETE)
	    {
	      /* if no error (i.e. just not finished yet), then DON'T execute this code */
	      io->iostate = IOSTATE_INITIAL;
	      ASSERT (ResetEvent (io->overlapped.hEvent));
	      msg (D_WIN32_IO | M_ERRNO_SOCK, "WIN32 I/O: Socket Completion error");
	    }
	}
      break;

    case IOSTATE_IMMEDIATE_RETURN:
      io->iostate = IOSTATE_INITIAL;
      ASSERT (ResetEvent (io->overlapped.hEvent));
      if (io->status)
	{
	  /* error return for a non-queued operation */
	  WSASetLastError (io->status);
	  ret = -1;
	  msg (D_WIN32_IO | M_ERRNO_SOCK, "WIN32 I/O: Socket Completion non-queued error");
	}
      else
	{
	  /* successful return for a non-queued operation */
	  if (buf)
	    *buf = io->buf;
	  ret = io->size;
	  msg (D_WIN32_IO, "WIN32 I/O: Socket Completion non-queued success [%d]", ret);
	}
      break;

    case IOSTATE_INITIAL: /* were we called without proper queueing? */
      WSASetLastError (WSAEINVAL);
      ret = -1;
      msg (D_WIN32_IO, "WIN32 I/O: Socket Completion BAD STATE");
      break;

    default:
      ASSERT (0);
    }
  
  /* return from address if requested */
  if (from)
    {
      if (ret >= 0 && io->addr_defined)
	{
	  if (io->addrlen != sizeof (io->addr))
	    bad_address_length (io->addrlen, sizeof (io->addr));
	  *from = io->addr;
	}
      else
	CLEAR (*from);
    }
  
  if (buf)
    buf->len = ret;
  return ret;
}

#endif /* WIN32 */