mdw@git.distorted.org.uk Git - unet/blob - unet.h

   1 /* -*-c-*-
   2  *
   3  * $Id: unet.h,v 1.2 2001/02/19 19:10:28 mdw Exp $
   4  *
   5  * User-space network device support.
   6  *
   7  * (c) 1998 Mark Wooding
   8  */
   9
  10 /*----- Licensing notice --------------------------------------------------*
  11  *
  12  * This file is part of Usernet.
  13  *
  14  * Usernet is free software; you can redistribute it and/or modify
  15  * it under the terms of the GNU General Public License as published by
  16  * the Free Software Foundation; either version 2 of the License, or
  17  * (at your option) any later version.
  18  *
  19  * Usernet is distributed in the hope that it will be useful,
  20  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  21  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  22  * GNU General Public License for more details.
  23  *
  24  * You should have received a copy of the GNU General Public License
  25  * along with Usernet; if not, write to the Free Software Foundation,
  26  * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  27  */
  28
  29 /*----- Revision history --------------------------------------------------*
  30  *
  31  * $Log: unet.h,v $
  32  * Revision 1.2  2001/02/19 19:10:28  mdw
  33  * New option to allow changing interface flags.
  34  *
  35  * Revision 1.1  2001/01/25 22:03:39  mdw
  36  * Initial check-in (somewhat belated).
  37  *
  38  */
  39
  40 #ifndef _LINUX_UNET_H
  41 #define _LINUX_UNET_H
  42
  43 #ifdef __cplusplus
  44   extern "C" {
  45 #endif
  46
  47 /*----- What's the story? -------------------------------------------------*
  48  *
  49  * Based on a conversation with Clive Jones about FreeBSD's tunnel device,
  50  * I've decided to try to write something similar.  The basic idea is to
  51  * tie together a character device and a network interface, so that anything
  52  * written to one pops out the other.  I create a device /dev/unet.
  53  * Each open(2) of my device creates a network device, whose name can be
  54  * read by calling ioctl(2).  A read(2) on the device fetches the next
  55  * packet received from the network interface; conversely, a write(2) sends
  56  * a network packet through the interface.
  57  *
  58  * Permissions on /dev/unet ought to be fairly strict.  Remember that
  59  * anyone who can get access to it can inject arbitrary IP packets.
  60  *
  61  * This is my first stab at hacking Linux, so there'll be mistakes and
  62  * infelicities.  All I ask is that you tell me what they are.
  63  *
  64  *                                              [mdw]
  65  *                                              mdw@excessus.demon.co.uk
  66  */
  67
  68 /*----- @ioctl@(2) calls supported ----------------------------------------*/
  69
  70 /* --- @UNIOCGINFO@ --- *
  71  *
  72  * Reads useful information about a unet.  The argument is a pointer to a
  73  * @unet_info@ structure, which is filled in by the call.  As a special case,
  74  * the argument may be a null pointer, in which case the call does nothing
  75  * and may be used to verify that a file descriptor refers to a Usernet
  76  * attachment.
  77  */
  78
  79 #define UNIOCGINFO _IOR('U', 0, sizeof(struct unet_info))
  80
  81 #define UNET_NAMEMAX 20
  82
  83 struct unet_info {
  84   char uni_ifname[UNET_NAMEMAX];        /* Interface name string */
  85   unsigned short uni_mtu;               /* Maximum transmission unit */
  86   unsigned short uni_family;            /* My address family */
  87   unsigned short uni_proto;             /* Protocol to stamp on packets */
  88   unsigned int uni_flags;               /* Various useful flags */
  89 };
  90
  91 #define UNIF_TRANS 1                    /* This device is transient */
  92 #define UNIF_OPEN 2                     /* Not useful to users */
  93 #define UNIF_DEBUG 4                    /* Debugging enable flag */
  94
  95 /* --- @UNIOCSDEBUG@ --- *
  96  *
  97  * Sets the debugging state for the attachment.  When the debug flag is set,
  98  * all packets sent and received by the device will be logged, as will other
  99  * events.
 100  */
 101
 102 #define UNIOCSDEBUG _IO('U', 1)
 103
 104 /* --- @UNIOCGPROTO@ --- *
 105  *
 106  * Reads the protocol stamped on packets received through the character
 107  * device interface.  The default is @ETH_P_IP@; the various values are
 108  * defined in @<linux/if_ether.h>@.
 109  */
 110
 111 #define UNIOCGPROTO _IO('U', 2)
 112
 113 /* --- @UNIOCSPROTO@ --- *
 114  *
 115  * Sets the protocol to be stamped on outgoing packets.
 116  */
 117
 118 #define UNIOCSPROTO _IO('U', 3)
 119
 120 /* --- @UNIOCGGDEBUG@ --- *
 121  *
 122  * Gets the global debugging flag.
 123  */
 124
 125 #define UNIOCGGDEBUG _IO('U', 4)
 126
 127 /* --- @UNIOCSGDEBUG@ --- *
 128  *
 129  * Sets the global debugging flag.  This is only available when runtime
 130  * debugging configuration is compiled in.
 131  */
 132
 133 #define UNIOCSGDEBUG _IO('U', 5)
 134
 135 /* --- @UNIOCDUMP@ --- *
 136  *
 137  * Dumps a unet block's information to the debug device.
 138  */
 139
 140 #define UNIOCDUMP _IO('U', 6)
 141
 142 /* --- @UNIOCGMAXIF@ --- *
 143  *
 144  * Returns the maximum number of interfaces allowed.
 145  */
 146
 147 #define UNIOCGMAXIF _IO('U', 7)
 148
 149 /* --- @UNIOCGMAXIF@ --- *
 150  *
 151  * Sets the maximum number of interfaces allowed.  It's an error to lower
 152  * this below the number of the highest currently-used interface.
 153  */
 154
 155 #define UNIOCSMAXIF _IO('U', 8)
 156
 157 /* --- @UNIOCGIFFLAGS@ --- *
 158  *
 159  * Gets interface flags.  To complement @UNIOCSIFFLAGS@.
 160  */
 161
 162 #define UNIOCGIFFLAGS _IO('U', 9)
 163
 164 /* --- @UNIOCSIFFLAGS@ --- *
 165  *
 166  * Sets interface flags.  This is required because there's no other sensible
 167  * way to (e.g.) change the point-to-point flag.
 168  */
 169
 170 #define UNIOCSIFFLAGS _IO('U', 10)
 171
 172 /*----- That's all, folks -------------------------------------------------*/
 173
 174 #ifdef __cplusplus
 175   }
 176 #endif
 177
 178 #endif