gpxe/src/core/interface.c

   1 /*
   2  * Copyright (C) 2007 Michael Brown <mbrown@fensystems.co.uk>.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public License as
   6  * published by the Free Software Foundation; either version 2 of the
   7  * License, or any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful, but
  10  * WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  17  */
  18
  19 FILE_LICENCE ( GPL2_OR_LATER );
  20
  21 #include <gpxe/interface.h>
  22
  23 /** @file
  24  *
  25  * Object communication interfaces
  26  *
  27  */
  28
  29 /**
  30  * Plug an interface into a new destination interface
  31  *
  32  * @v intf              Interface
  33  * @v dest              New destination interface
  34  *
  35  * The reference to the existing destination interface is dropped, a
  36  * reference to the new destination interface is obtained, and the
  37  * interface is updated to point to the new destination interface.
  38  *
  39  * Note that there is no "unplug" call; instead you must plug the
  40  * interface into a null interface.
  41  */
  42 void plug ( struct interface *intf, struct interface *dest ) {
  43         DBGC ( intf, "INTF %p moving from INTF %p to INTF %p\n",
  44                intf, intf->dest, dest );
  45         intf_put ( intf->dest );
  46         intf->dest = intf_get ( dest );
  47 }
  48
  49 /**
  50  * Plug two interfaces together
  51  *
  52  * @v a                 Interface A
  53  * @v b                 Interface B
  54  *
  55  * Plugs interface A into interface B, and interface B into interface
  56  * A.  (The basic plug() function is unidirectional; this function is
  57  * merely a shorthand for two calls to plug(), hence the name.)
  58  */
  59 void plug_plug ( struct interface *a, struct interface *b ) {
  60         plug ( a, b );
  61         plug ( b, a );
  62 }