sys/net/if_clone.c

   1 /*
   2  * Copyright (c) 1980, 1986, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 3. Neither the name of the University nor the names of its contributors
  14  *    may be used to endorse or promote products derived from this software
  15  *    without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  *
  29  *      @(#)if.c        8.3 (Berkeley) 1/4/94
  30  * $FreeBSD: src/sys/net/if.c,v 1.185 2004/03/13 02:35:03 brooks Exp $
  31  * $DragonFly: src/sys/net/if_clone.c,v 1.1 2008/01/11 11:59:40 sephe Exp $
  32  */
  33
  34 #include <sys/param.h>
  35 #include <sys/kernel.h>
  36 #include <sys/malloc.h>
  37
  38 #include <net/if.h>
  39 #include <net/if_clone.h>
  40
  41 static LIST_HEAD(, if_clone) if_cloners = LIST_HEAD_INITIALIZER(if_cloners);
  42 static int              if_cloners_count;
  43
  44 MALLOC_DEFINE(M_CLONE, "clone", "interface cloning framework");
  45
  46 static struct if_clone  *if_clone_lookup(const char *, int *);
  47
  48 /*
  49  * Create a clone network interface.
  50  */
  51 int
  52 if_clone_create(char *name, int len, caddr_t params)
  53 {
  54         struct if_clone *ifc;
  55         char *dp;
  56         int wildcard, bytoff, bitoff;
  57         int unit;
  58         int err;
  59
  60         ifc = if_clone_lookup(name, &unit);
  61         if (ifc == NULL)
  62                 return (EINVAL);
  63
  64         ifnet_lock();
  65         if (ifunit(name) != NULL) {
  66                 ifnet_unlock();
  67                 return (EEXIST);
  68         }
  69         ifnet_unlock();
  70
  71         bytoff = bitoff = 0;
  72         wildcard = (unit < 0);
  73         /*
  74          * Find a free unit if none was given.
  75          */
  76         if (wildcard) {
  77                 while (bytoff < ifc->ifc_bmlen &&
  78                     ifc->ifc_units[bytoff] == 0xff)
  79                         bytoff++;
  80                 if (bytoff >= ifc->ifc_bmlen)
  81                         return (ENOSPC);
  82                 while ((ifc->ifc_units[bytoff] & (1 << bitoff)) != 0)
  83                         bitoff++;
  84                 unit = (bytoff << 3) + bitoff;
  85         }
  86
  87         if (unit > ifc->ifc_maxunit)
  88                 return (ENXIO);
  89
  90         err = (*ifc->ifc_create)(ifc, unit, params);
  91         if (err != 0)
  92                 return (err);
  93
  94         if (!wildcard) {
  95                 bytoff = unit >> 3;
  96                 bitoff = unit - (bytoff << 3);
  97         }
  98
  99         /*
 100          * Allocate the unit in the bitmap.
 101          */
 102         KASSERT((ifc->ifc_units[bytoff] & (1 << bitoff)) == 0,
 103             ("%s: bit is already set", __func__));
 104         ifc->ifc_units[bytoff] |= (1 << bitoff);
 105
 106         /* In the wildcard case, we need to update the name. */
 107         if (wildcard) {
 108                 for (dp = name; *dp != '\0'; dp++);
 109                 if (ksnprintf(dp, len - (dp-name), "%d", unit) >
 110                     len - (dp-name) - 1) {
 111                         /*
 112                          * This can only be a programmer error and
 113                          * there's no straightforward way to recover if
 114                          * it happens.
 115                          */
 116                         panic("if_clone_create(): interface name too long");
 117                 }
 118
 119         }
 120
 121         EVENTHANDLER_INVOKE(if_clone_event, ifc);
 122
 123         return (0);
 124 }
 125
 126 /*
 127  * Destroy a clone network interface.
 128  */
 129 int
 130 if_clone_destroy(const char *name)
 131 {
 132         struct if_clone *ifc;
 133         struct ifnet *ifp;
 134         int bytoff, bitoff;
 135         int unit, error;
 136
 137         ifc = if_clone_lookup(name, &unit);
 138         if (ifc == NULL)
 139                 return (EINVAL);
 140
 141         if (unit < ifc->ifc_minifs)
 142                 return (EINVAL);
 143
 144         ifnet_lock();
 145
 146         ifp = ifunit(name);
 147         if (ifp == NULL) {
 148                 ifnet_unlock();
 149                 return (ENXIO);
 150         }
 151
 152         if (ifc->ifc_destroy == NULL) {
 153                 ifnet_unlock();
 154                 return (EOPNOTSUPP);
 155         }
 156
 157         error = ifc->ifc_destroy(ifp);
 158         if (error) {
 159                 ifnet_unlock();
 160                 return error;
 161         }
 162
 163         ifnet_unlock();
 164
 165         /*
 166          * Compute offset in the bitmap and deallocate the unit.
 167          */
 168         bytoff = unit >> 3;
 169         bitoff = unit - (bytoff << 3);
 170         KASSERT((ifc->ifc_units[bytoff] & (1 << bitoff)) != 0,
 171             ("%s: bit is already cleared", __func__));
 172         ifc->ifc_units[bytoff] &= ~(1 << bitoff);
 173         return (0);
 174 }
 175
 176 /*
 177  * Register a network interface cloner.
 178  */
 179 void
 180 if_clone_attach(struct if_clone *ifc)
 181 {
 182         int bytoff, bitoff;
 183         int err;
 184         int len, maxclone;
 185         int unit;
 186         struct if_clone *ifct;
 187
 188         /* Duplicate entries in if_cloners lead
 189            to infinite loops in if_clone_create */
 190         LIST_FOREACH(ifct, &if_cloners, ifc_list) {
 191                 if (ifct == ifc) {
 192                         panic("%s: duplicate entry %s\n",
 193                               __func__, ifc->ifc_name);
 194                 }
 195         }
 196
 197         KASSERT(ifc->ifc_minifs - 1 <= ifc->ifc_maxunit,
 198             ("%s: %s requested more units then allowed (%d > %d)",
 199             __func__, ifc->ifc_name, ifc->ifc_minifs,
 200             ifc->ifc_maxunit + 1));
 201         /*
 202          * Compute bitmap size and allocate it.
 203          */
 204         maxclone = ifc->ifc_maxunit + 1;
 205         len = maxclone >> 3;
 206         if ((len << 3) < maxclone)
 207                 len++;
 208         ifc->ifc_units = kmalloc(len, M_CLONE, M_WAITOK | M_ZERO);
 209         ifc->ifc_bmlen = len;
 210
 211         LIST_INSERT_HEAD(&if_cloners, ifc, ifc_list);
 212         if_cloners_count++;
 213
 214         for (unit = 0; unit < ifc->ifc_minifs; unit++) {
 215                 err = (*ifc->ifc_create)(ifc, unit, NULL);
 216                 KASSERT(err == 0,
 217                     ("%s: failed to create required interface %s%d",
 218                     __func__, ifc->ifc_name, unit));
 219
 220                 /* Allocate the unit in the bitmap. */
 221                 bytoff = unit >> 3;
 222                 bitoff = unit - (bytoff << 3);
 223                 ifc->ifc_units[bytoff] |= (1 << bitoff);
 224         }
 225 }
 226
 227 /*
 228  * Unregister a network interface cloner.
 229  */
 230 void
 231 if_clone_detach(struct if_clone *ifc)
 232 {
 233
 234         LIST_REMOVE(ifc, ifc_list);
 235         kfree(ifc->ifc_units, M_CLONE);
 236         if_cloners_count--;
 237 }
 238
 239 /*
 240  * Provide list of interface cloners to userspace.
 241  */
 242 int
 243 if_clone_list(struct if_clonereq *ifcr)
 244 {
 245         char outbuf[IFNAMSIZ], *dst;
 246         struct if_clone *ifc;
 247         int count, error = 0;
 248
 249         ifcr->ifcr_total = if_cloners_count;
 250         if ((dst = ifcr->ifcr_buffer) == NULL) {
 251                 /* Just asking how many there are. */
 252                 return (0);
 253         }
 254
 255         if (ifcr->ifcr_count < 0)
 256                 return (EINVAL);
 257
 258         count = (if_cloners_count < ifcr->ifcr_count) ?
 259             if_cloners_count : ifcr->ifcr_count;
 260
 261         for (ifc = LIST_FIRST(&if_cloners); ifc != NULL && count != 0;
 262              ifc = LIST_NEXT(ifc, ifc_list), count--, dst += IFNAMSIZ) {
 263                 strlcpy(outbuf, ifc->ifc_name, IFNAMSIZ);
 264                 error = copyout(outbuf, dst, IFNAMSIZ);
 265                 if (error)
 266                         break;
 267         }
 268
 269         return (error);
 270 }
 271
 272 /*
 273  * Look up a network interface cloner.
 274  */
 275 static struct if_clone *
 276 if_clone_lookup(const char *name, int *unitp)
 277 {
 278         struct if_clone *ifc;
 279         const char *cp;
 280         int i;
 281
 282         for (ifc = LIST_FIRST(&if_cloners); ifc != NULL;) {
 283                 for (cp = name, i = 0; i < ifc->ifc_namelen; i++, cp++) {
 284                         if (ifc->ifc_name[i] != *cp)
 285                                 goto next_ifc;
 286                 }
 287                 goto found_name;
 288  next_ifc:
 289                 ifc = LIST_NEXT(ifc, ifc_list);
 290         }
 291
 292         /* No match. */
 293         return (NULL);
 294
 295  found_name:
 296         if (*cp == '\0') {
 297                 i = -1;
 298         } else {
 299                 for (i = 0; *cp != '\0'; cp++) {
 300                         if (*cp < '0' || *cp > '9') {
 301                                 /* Bogus unit number. */
 302                                 return (NULL);
 303                         }
 304                         i = (i * 10) + (*cp - '0');
 305                 }
 306         }
 307
 308         if (unitp != NULL)
 309                 *unitp = i;
 310         return (ifc);
 311 }