mdw@git.distorted.org.uk Git - tripe/blob - tun-unet.c

   1 /* -*-c-*-
   2  *
   3  * $Id$
   4  *
   5  * Tunnel interface based on Linux Usernet
   6  *
   7  * (c) 2001 Straylight/Edgeware
   8  */
   9
  10 /*----- Licensing notice --------------------------------------------------*
  11  *
  12  * This file is part of Trivial IP Encryption (TrIPE).
  13  *
  14  * TrIPE 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  * TrIPE 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 TrIPE; if not, write to the Free Software Foundation,
  26  * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  27  */
  28
  29 /*----- Header files ------------------------------------------------------*/
  30
  31 #define TUN_INTERNALS
  32
  33 #include "tripe.h"
  34
  35 #ifdef TUN_UNET
  36 #  include <sys/ioctl.h>
  37 #  include <net/if.h>
  38 #  include <unet.h>
  39 #endif
  40
  41 /*----- Main code ---------------------------------------------------------*/
  42
  43 #ifdef TUN_UNET
  44
  45 struct tunnel {
  46   const tunnel_ops *ops;                /* Pointer to operations */
  47   sel_file f;                           /* Selector for Usernet device */
  48   struct peer *p;                       /* Pointer to my peer */
  49 };
  50
  51 /* --- @t_ifname@ --- *
  52  *
  53  * Arguments:   @tunnel *t@ = pointer to tunnel block
  54  *
  55  * Returns:     A pointer to the tunnel's interface name.
  56  */
  57
  58 static const char *t_ifname(tunnel *t)
  59 {
  60   static char b[UNET_NAMEMAX];
  61   struct unet_info uni;
  62   if (ioctl(t->f.fd, UNIOCGINFO, &uni)) {
  63     a_warn("TUN - unet getinfo-error -- %s", strerror(errno));
  64     return ("<error>");
  65   }
  66   if (strlen(uni.uni_ifname) + 1 > sizeof(b)) {
  67     a_warn("TUN - unet ifname-too-long");
  68     return ("<error>");
  69   }
  70   strcpy(b, uni.uni_ifname);
  71   return (b);
  72 }
  73
  74 /* --- @t_read@ --- *
  75  *
  76  * Arguments:   @int fd@ = file descriptor to read
  77  *              @unsigned mode@ = what's happened
  78  *              @void *v@ = pointer to tunnel block
  79  *
  80  * Returns:     ---
  81  *
  82  * Use:         Reads data from the tunnel.
  83  */
  84
  85 static void t_read(int fd, unsigned mode, void *v)
  86 {
  87   tunnel *t = v;
  88   ssize_t n;
  89   buf b;
  90
  91   n = read(fd, buf_i, sizeof(buf_i));
  92   if (n < 0) {
  93     a_warn("TUN %s read-error -- %s", t_ifname(t), strerror(errno));
  94     return;
  95   }
  96   IF_TRACING(T_TUNNEL, {
  97     trace(T_TUNNEL, "tunnel: packet arrived");
  98     trace_block(T_PACKET, "tunnel: packet contents", buf_i, n);
  99   })
 100   buf_init(&b, buf_i, n);
 101   p_tun(t->p, &b);
 102 }
 103
 104 /* --- @t_init@ --- *
 105  *
 106  * Arguments:   ---
 107  *
 108  * Returns:     ---
 109  *
 110  * Use:         Initializes the tunneling system.  Maybe this will require
 111  *              opening file descriptors or something.
 112  */
 113
 114 static void t_init(void) { return; }
 115
 116 /* --- @t_create@ --- *
 117  *
 118  * Arguments:   @tunnel *t@ = pointer to tunnel block
 119  *              @peer *p@ = pointer to peer block
 120  *
 121  * Returns:     A tunnel block if it worked, or null on failure.
 122  *
 123  * Use:         Initializes a new tunnel.
 124  */
 125
 126 static tunnel *t_create(peer *p)
 127 {
 128   int fd;
 129   tunnel *t;
 130   int f;
 131
 132   if ((fd = open("/dev/unet", O_RDWR)) < 0) {
 133     a_warn("TUN - open-error /dev/unet -- %s", strerror(errno));
 134     return (0);
 135   }
 136   fdflags(fd, O_NONBLOCK, O_NONBLOCK, FD_CLOEXEC, FD_CLOEXEC);
 137   if ((f = ioctl(fd, UNIOCGIFFLAGS)) < 0 ||
 138       ioctl(fd, UNIOCSIFFLAGS, f | IFF_POINTOPOINT)) {
 139     a_warn("TUN - unet config-error -- %s", strerror(errno));
 140     close(fd);
 141     return (0);
 142   }
 143   t = CREATE(tunnel);
 144   t->ops = &tun_unet;
 145   t->p = p;
 146   sel_initfile(&sel, &t->f, fd, SEL_READ, t_read, t);
 147   sel_addfile(&t->f);
 148   T( trace(T_TUNNEL, "tunnel: attached interface %s to peer `%s'",
 149            t_ifname(t), p_name(p)); )
 150   return (t);
 151 }
 152
 153 /* --- @t_inject@ --- *
 154  *
 155  * Arguments:   @tunnel *t@ = pointer to tunnel block
 156  *              @buf *b@ = buffer to send
 157  *
 158  * Returns:     ---
 159  *
 160  * Use:         Injects a packet into the local network stack.
 161  */
 162
 163 static void t_inject(tunnel *t, buf *b)
 164 {
 165   IF_TRACING(T_TUNNEL, {
 166     trace(T_TUNNEL, "tunnel: inject decrypted packet");
 167     trace_block(T_PACKET, "tunnel: packet contents", BBASE(b), BLEN(b));
 168   })
 169   write(t->f.fd, BBASE(b), BLEN(b));
 170 }
 171
 172 /* --- @t_destroy@ --- *
 173  *
 174  * Arguments:   @tunnel *t@ = pointer to tunnel block
 175  *
 176  * Returns:     ---
 177  *
 178  * Use:         Destroys a tunnel.
 179  */
 180
 181 static void t_destroy(tunnel *t)
 182 {
 183   sel_rmfile(&t->f);
 184   close(t->f.fd);
 185   DESTROY(t);
 186 }
 187
 188 const tunnel_ops tun_unet = {
 189   "unet",
 190   t_init,
 191   t_create,
 192   t_ifname,
 193   t_inject,
 194   t_destroy
 195 };
 196
 197 #endif
 198
 199 /*----- That's all, folks -------------------------------------------------*/