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. All advertising materials mentioning features or use of this software
  14  *    must display the following acknowledgement:
  15  *      This product includes software developed by the University of
  16  *      California, Berkeley and its contributors.
  17  * 4. Neither the name of the University nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  *
  33  *      @(#)if.c        8.3 (Berkeley) 1/4/94
  34  * $FreeBSD: src/sys/net/if.c,v 1.185 2004/03/13 02:35:03 brooks Exp $
  35  * $DragonFly: src/sys/net/if_clone.c,v 1.1 2008/01/11 11:59:40 sephe Exp $
  36  */
  37
  38 #include <sys/param.h>
  39 #include <sys/kernel.h>
  40 #include <sys/malloc.h>
  41
  42 #include <net/if.h>
  43 #include <net/if_clone.h>
  44
  45 static LIST_HEAD(, if_clone) if_cloners = LIST_HEAD_INITIALIZER(if_cloners);
  46 static int              if_cloners_count;
  47
  48 MALLOC_DEFINE(M_CLONE, "clone", "interface cloning framework");
  49
  50 static struct if_clone  *if_clone_lookup(const char *, int *);
  51
  52 /*
  53  * Create a clone network interface.
  54  */
  55 int
  56 if_clone_create(char *name, int len)
  57 {
  58         struct if_clone *ifc;
  59         char *dp;
  60         int wildcard, bytoff, bitoff;
  61         int unit;
  62         int err;
  63
  64         ifc = if_clone_lookup(name, &unit);
  65         if (ifc == NULL)
  66                 return (EINVAL);
  67
  68         if (ifunit(name) != NULL)
  69                 return (EEXIST);
  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);
  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;
 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         ifp = ifunit(name);
 145         if (ifp == NULL)
 146                 return (ENXIO);
 147
 148         if (ifc->ifc_destroy == NULL)
 149                 return (EOPNOTSUPP);
 150
 151         (*ifc->ifc_destroy)(ifp);
 152
 153         /*
 154          * Compute offset in the bitmap and deallocate the unit.
 155          */
 156         bytoff = unit >> 3;
 157         bitoff = unit - (bytoff << 3);
 158         KASSERT((ifc->ifc_units[bytoff] & (1 << bitoff)) != 0,
 159             ("%s: bit is already cleared", __func__));
 160         ifc->ifc_units[bytoff] &= ~(1 << bitoff);
 161         return (0);
 162 }
 163
 164 /*
 165  * Register a network interface cloner.
 166  */
 167 void
 168 if_clone_attach(struct if_clone *ifc)
 169 {
 170         int bytoff, bitoff;
 171         int err;
 172         int len, maxclone;
 173         int unit;
 174
 175         KASSERT(ifc->ifc_minifs - 1 <= ifc->ifc_maxunit,
 176             ("%s: %s requested more units then allowed (%d > %d)",
 177             __func__, ifc->ifc_name, ifc->ifc_minifs,
 178             ifc->ifc_maxunit + 1));
 179         /*
 180          * Compute bitmap size and allocate it.
 181          */
 182         maxclone = ifc->ifc_maxunit + 1;
 183         len = maxclone >> 3;
 184         if ((len << 3) < maxclone)
 185                 len++;
 186         ifc->ifc_units = kmalloc(len, M_CLONE, M_WAITOK | M_ZERO);
 187         ifc->ifc_bmlen = len;
 188
 189         LIST_INSERT_HEAD(&if_cloners, ifc, ifc_list);
 190         if_cloners_count++;
 191
 192         for (unit = 0; unit < ifc->ifc_minifs; unit++) {
 193                 err = (*ifc->ifc_create)(ifc, unit);
 194                 KASSERT(err == 0,
 195                     ("%s: failed to create required interface %s%d",
 196                     __func__, ifc->ifc_name, unit));
 197
 198                 /* Allocate the unit in the bitmap. */
 199                 bytoff = unit >> 3;
 200                 bitoff = unit - (bytoff << 3);
 201                 ifc->ifc_units[bytoff] |= (1 << bitoff);
 202         }
 203 }
 204
 205 /*
 206  * Unregister a network interface cloner.
 207  */
 208 void
 209 if_clone_detach(struct if_clone *ifc)
 210 {
 211
 212         LIST_REMOVE(ifc, ifc_list);
 213         kfree(ifc->ifc_units, M_CLONE);
 214         if_cloners_count--;
 215 }
 216
 217 /*
 218  * Provide list of interface cloners to userspace.
 219  */
 220 int
 221 if_clone_list(struct if_clonereq *ifcr)
 222 {
 223         char outbuf[IFNAMSIZ], *dst;
 224         struct if_clone *ifc;
 225         int count, error = 0;
 226
 227         ifcr->ifcr_total = if_cloners_count;
 228         if ((dst = ifcr->ifcr_buffer) == NULL) {
 229                 /* Just asking how many there are. */
 230                 return (0);
 231         }
 232
 233         if (ifcr->ifcr_count < 0)
 234                 return (EINVAL);
 235
 236         count = (if_cloners_count < ifcr->ifcr_count) ?
 237             if_cloners_count : ifcr->ifcr_count;
 238
 239         for (ifc = LIST_FIRST(&if_cloners); ifc != NULL && count != 0;
 240              ifc = LIST_NEXT(ifc, ifc_list), count--, dst += IFNAMSIZ) {
 241                 strlcpy(outbuf, ifc->ifc_name, IFNAMSIZ);
 242                 error = copyout(outbuf, dst, IFNAMSIZ);
 243                 if (error)
 244                         break;
 245         }
 246
 247         return (error);
 248 }
 249
 250 /*
 251  * Look up a network interface cloner.
 252  */
 253 static struct if_clone *
 254 if_clone_lookup(const char *name, int *unitp)
 255 {
 256         struct if_clone *ifc;
 257         const char *cp;
 258         int i;
 259
 260         for (ifc = LIST_FIRST(&if_cloners); ifc != NULL;) {
 261                 for (cp = name, i = 0; i < ifc->ifc_namelen; i++, cp++) {
 262                         if (ifc->ifc_name[i] != *cp)
 263                                 goto next_ifc;
 264                 }
 265                 goto found_name;
 266  next_ifc:
 267                 ifc = LIST_NEXT(ifc, ifc_list);
 268         }
 269
 270         /* No match. */
 271         return ((struct if_clone *)NULL);
 272
 273  found_name:
 274         if (*cp == '\0') {
 275                 i = -1;
 276         } else {
 277                 for (i = 0; *cp != '\0'; cp++) {
 278                         if (*cp < '0' || *cp > '9') {
 279                                 /* Bogus unit number. */
 280                                 return (NULL);
 281                         }
 282                         i = (i * 10) + (*cp - '0');
 283                 }
 284         }
 285
 286         if (unitp != NULL)
 287                 *unitp = i;
 288         return (ifc);
 289 }