if_clone.c

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    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  * 4. 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        8.5 (Berkeley) 1/9/95
   30  * $FreeBSD: releng/5.3/sys/net/if_clone.c 136588 2004-10-16 08:43:07Z cvs2svn $
   31  */
   32 
   33 #include <sys/param.h>
   34 #include <sys/malloc.h>
   35 #include <sys/lock.h>
   36 #include <sys/mutex.h>
   37 #include <sys/kernel.h>
   38 #include <sys/systm.h>
   39 #include <sys/types.h>
   40 #include <sys/socket.h>
   41 
   42 #include <net/if.h>
   43 #include <net/if_clone.h>
   44 #if 0
   45 #include <net/if_dl.h>
   46 #endif
   47 #include <net/if_types.h>
   48 #include <net/if_var.h>
   49 #include <net/radix.h>
   50 #include <net/route.h>
   51 
   52 static void             if_clone_free(struct if_clone *ifc);
   53 
   54 static struct mtx       if_cloners_mtx;
   55 static int              if_cloners_count;
   56 LIST_HEAD(, if_clone)   if_cloners = LIST_HEAD_INITIALIZER(if_cloners);
   57 
   58 #define IF_CLONERS_LOCK_INIT()          \
   59     mtx_init(&if_cloners_mtx, "if_cloners lock", NULL, MTX_DEF)
   60 #define IF_CLONERS_LOCK_ASSERT()        mtx_assert(&if_cloners_mtx, MA_OWNED)
   61 #define IF_CLONERS_LOCK()               mtx_lock(&if_cloners_mtx)
   62 #define IF_CLONERS_UNLOCK()             mtx_unlock(&if_cloners_mtx)
   63 
   64 #define IF_CLONE_LOCK_INIT(ifc)         \
   65     mtx_init(&(ifc)->ifc_mtx, "if_clone lock", NULL, MTX_DEF)
   66 #define IF_CLONE_LOCK_DESTROY(ifc)      mtx_destroy(&(ifc)->ifc_mtx)
   67 #define IF_CLONE_LOCK_ASSERT(ifc)       mtx_assert(&(ifc)->ifc_mtx, MA_OWNED)
   68 #define IF_CLONE_LOCK(ifc)              mtx_lock(&(ifc)->ifc_mtx)
   69 #define IF_CLONE_UNLOCK(ifc)            mtx_unlock(&(ifc)->ifc_mtx)
   70 
   71 #define IF_CLONE_ADDREF(ifc)                                            \
   72         do {                                                            \
   73                 IF_CLONE_LOCK(ifc);                                     \
   74                 IF_CLONE_ADDREF_LOCKED(ifc);                            \
   75                 IF_CLONE_UNLOCK(ifc);                                   \
   76         } while (0)
   77 #define IF_CLONE_ADDREF_LOCKED(ifc)                                     \
   78         do {                                                            \
   79                 IF_CLONE_LOCK_ASSERT(ifc);                              \
   80                 KASSERT((ifc)->ifc_refcnt >= 0,                         \
   81                     ("negative refcnt %ld", (ifc)->ifc_refcnt));        \
   82                 (ifc)->ifc_refcnt++;                                    \
   83         } while (0)
   84 #define IF_CLONE_REMREF(ifc)                                            \
   85         do {                                                            \
   86                 IF_CLONE_LOCK(ifc);                                     \
   87                 IF_CLONE_REMREF_LOCKED(ifc);                            \
   88         } while (0)
   89 #define IF_CLONE_REMREF_LOCKED(ifc)                                     \
   90         do {                                                            \
   91                 IF_CLONE_LOCK_ASSERT(ifc);                              \
   92                 KASSERT((ifc)->ifc_refcnt > 0,                          \
   93                     ("bogus refcnt %ld", (ifc)->ifc_refcnt));           \
   94                 if (--(ifc)->ifc_refcnt == 0) {                         \
   95                         IF_CLONE_UNLOCK(ifc);                           \
   96                         if_clone_free(ifc);                             \
   97                 } else {                                                \
   98                         /* silently free the lock */                    \
   99                         IF_CLONE_UNLOCK(ifc);                           \
  100                 }                                                       \
  101         } while (0)
  102 
  103 MALLOC_DEFINE(M_CLONE, "clone", "interface cloning framework");
  104 
  105 void
  106 if_clone_init(void)
  107 {
  108         IF_CLONERS_LOCK_INIT();
  109 }
  110 
  111 /*
  112  * Create a clone network interface.
  113  */
  114 int
  115 if_clone_create(char *name, size_t len)
  116 {
  117         int err;
  118         struct if_clone *ifc;
  119 
  120         if (ifunit(name) != NULL)
  121                 return (EEXIST);
  122 
  123         /* Try to find an applicable cloner for this request */
  124         IF_CLONERS_LOCK();
  125         LIST_FOREACH(ifc, &if_cloners, ifc_list) {
  126                 if (ifc->ifc_match(ifc, name)) {
  127                         IF_CLONE_ADDREF(ifc);
  128                         break;
  129                 }
  130         }
  131         IF_CLONERS_UNLOCK();
  132 
  133         if (ifc == NULL)
  134                 return (EINVAL);
  135 
  136         err = (*ifc->ifc_create)(ifc, name, len);
  137         IF_CLONE_REMREF(ifc);
  138         return (err);
  139 }
  140 
  141 /*
  142  * Destroy a clone network interface.
  143  */
  144 int
  145 if_clone_destroy(const char *name)
  146 {
  147         int err;
  148         struct if_clone *ifc;
  149         struct ifnet *ifp;
  150 
  151         ifp = ifunit(name);
  152         if (ifp == NULL)
  153                 return (ENXIO);
  154 
  155         /* Find the cloner for this interface */
  156         IF_CLONERS_LOCK();
  157         LIST_FOREACH(ifc, &if_cloners, ifc_list) {
  158                 if (strcmp(ifc->ifc_name, ifp->if_dname) == 0) {
  159                         IF_CLONE_ADDREF(ifc);
  160                         break;
  161                 }
  162         }
  163         IF_CLONERS_UNLOCK();
  164         if (ifc == NULL)
  165                 return (EINVAL);
  166 
  167         if (ifc->ifc_destroy == NULL) {
  168                 err = EOPNOTSUPP;
  169                 goto done;
  170         }
  171 
  172         err =  (*ifc->ifc_destroy)(ifc, ifp);
  173 
  174 done:
  175         IF_CLONE_REMREF(ifc);
  176         return (err);
  177 }
  178 
  179 /*
  180  * Register a network interface cloner.
  181  */
  182 void
  183 if_clone_attach(struct if_clone *ifc)
  184 {
  185         int len, maxclone;
  186 
  187         /*
  188          * Compute bitmap size and allocate it.
  189          */
  190         maxclone = ifc->ifc_maxunit + 1;
  191         len = maxclone >> 3;
  192         if ((len << 3) < maxclone)
  193                 len++;
  194         ifc->ifc_units = malloc(len, M_CLONE, M_WAITOK | M_ZERO);
  195         ifc->ifc_bmlen = len;
  196         IF_CLONE_LOCK_INIT(ifc);
  197         IF_CLONE_ADDREF(ifc);
  198 
  199         IF_CLONERS_LOCK();
  200         LIST_INSERT_HEAD(&if_cloners, ifc, ifc_list);
  201         if_cloners_count++;
  202         IF_CLONERS_UNLOCK();
  203 
  204         if (ifc->ifc_attach != NULL)
  205                 (*ifc->ifc_attach)(ifc);
  206         EVENTHANDLER_INVOKE(if_clone_event, ifc);
  207 }
  208 
  209 /*
  210  * Unregister a network interface cloner.
  211  */
  212 void
  213 if_clone_detach(struct if_clone *ifc)
  214 {
  215 
  216         IF_CLONERS_LOCK();
  217         LIST_REMOVE(ifc, ifc_list);
  218         if_cloners_count--;
  219         IF_CLONERS_UNLOCK();
  220 
  221         IF_CLONE_REMREF(ifc);
  222 }
  223 
  224 static void
  225 if_clone_free(struct if_clone *ifc)
  226 {
  227 
  228         IF_CLONE_LOCK_DESTROY(ifc);
  229         free(ifc->ifc_units, M_CLONE);
  230 }
  231 
  232 /*
  233  * Provide list of interface cloners to userspace.
  234  */
  235 int
  236 if_clone_list(struct if_clonereq *ifcr)
  237 {
  238         char *buf, *dst, *outbuf = NULL;
  239         struct if_clone *ifc;
  240         int buf_count, count, err = 0;
  241 
  242         IF_CLONERS_LOCK();
  243         /*
  244          * Set our internal output buffer size.  We could end up not
  245          * reporting a cloner that is added between the unlock and lock
  246          * below, but that's not a major problem.  Not caping our
  247          * allocation to the number of cloners actually in the system
  248          * could be because that would let arbitrary users cause us to
  249          * allocate abritrary amounts of kernel memory.
  250          */
  251         buf_count = (if_cloners_count < ifcr->ifcr_count) ?
  252             if_cloners_count : ifcr->ifcr_count;
  253         IF_CLONERS_UNLOCK();
  254 
  255         outbuf = malloc(IFNAMSIZ*buf_count, M_CLONE, M_WAITOK | M_ZERO);
  256 
  257         IF_CLONERS_LOCK();
  258 
  259         ifcr->ifcr_total = if_cloners_count;
  260         if ((dst = ifcr->ifcr_buffer) == NULL) {
  261                 /* Just asking how many there are. */
  262                 goto done;
  263         }
  264 
  265         if (ifcr->ifcr_count < 0) {
  266                 err = EINVAL;
  267                 goto done;
  268         }
  269 
  270         count = (if_cloners_count < buf_count) ?
  271             if_cloners_count : buf_count;
  272 
  273         for (ifc = LIST_FIRST(&if_cloners), buf = outbuf;
  274             ifc != NULL && count != 0;
  275             ifc = LIST_NEXT(ifc, ifc_list), count--, buf += IFNAMSIZ) {
  276                 strlcpy(buf, ifc->ifc_name, IFNAMSIZ);
  277         }
  278 
  279 done:
  280         IF_CLONERS_UNLOCK();
  281         if (err == 0)
  282                 err = copyout(outbuf, dst, buf_count*IFNAMSIZ);
  283         if (outbuf != NULL)
  284                 free(outbuf, M_CLONE);
  285         return (err);
  286 }
  287 
  288 /*
  289  * A utility function to extract unit numbers from interface names of
  290  * the form name###.
  291  *
  292  * Returns 0 on success and an error on failure.
  293  */
  294 int
  295 ifc_name2unit(const char *name, int *unit)
  296 {
  297         const char      *cp;
  298 
  299         for (cp = name; *cp != '\0' && (*cp < '' || *cp > '9'); cp++);
  300         if (*cp == '\0') {
  301                 *unit = -1;
  302         } else {
  303                 for (*unit = 0; *cp != '\0'; cp++) {
  304                         if (*cp < '' || *cp > '9') {
  305                                 /* Bogus unit number. */
  306                                 return (EINVAL);
  307                         }
  308                         *unit = (*unit * 10) + (*cp - '');
  309                 }
  310         }
  311 
  312         return (0);
  313 }
  314 
  315 int
  316 ifc_alloc_unit(struct if_clone *ifc, int *unit)
  317 {
  318         int wildcard, bytoff, bitoff;
  319         int err = 0;
  320 
  321         IF_CLONE_LOCK(ifc);
  322 
  323         bytoff = bitoff = 0;
  324         wildcard = (*unit < 0);
  325         /*
  326          * Find a free unit if none was given.
  327          */
  328         if (wildcard) {
  329                 while ((bytoff < ifc->ifc_bmlen)
  330                     && (ifc->ifc_units[bytoff] == 0xff))
  331                         bytoff++;
  332                 if (bytoff >= ifc->ifc_bmlen) {
  333                         err = ENOSPC;
  334                         goto done;
  335                 }
  336                 while ((ifc->ifc_units[bytoff] & (1 << bitoff)) != 0)
  337                         bitoff++;
  338                 *unit = (bytoff << 3) + bitoff;
  339         }
  340 
  341         if (*unit > ifc->ifc_maxunit) {
  342                 err = ENOSPC;
  343                 goto done;
  344         }
  345 
  346         if (!wildcard) {
  347                 bytoff = *unit >> 3;
  348                 bitoff = *unit - (bytoff << 3);
  349         }
  350 
  351         if((ifc->ifc_units[bytoff] & (1 << bitoff)) != 0) {
  352                 err = EEXIST;
  353                 goto done;
  354         }
  355         /*
  356          * Allocate the unit in the bitmap.
  357          */
  358         ifc->ifc_units[bytoff] |= (1 << bitoff);
  359 
  360 done:
  361         IF_CLONE_UNLOCK(ifc);
  362         return (err);
  363 }
  364 
  365 void
  366 ifc_free_unit(struct if_clone *ifc, int unit)
  367 {
  368         int bytoff, bitoff;
  369 
  370 
  371         /*
  372          * Compute offset in the bitmap and deallocate the unit.
  373          */
  374         bytoff = unit >> 3;
  375         bitoff = unit - (bytoff << 3);
  376 
  377         IF_CLONE_LOCK(ifc);
  378         KASSERT((ifc->ifc_units[bytoff] & (1 << bitoff)) != 0,
  379             ("%s: bit is already cleared", __func__));
  380         ifc->ifc_units[bytoff] &= ~(1 << bitoff);
  381         IF_CLONE_UNLOCK(ifc);
  382 }
  383 
  384 void
  385 ifc_simple_attach(struct if_clone *ifc)
  386 {
  387         int err;
  388         int unit;
  389         char name[IFNAMSIZ];
  390         struct ifc_simple_data *ifcs = ifc->ifc_data;
  391 
  392         KASSERT(ifcs->ifcs_minifs - 1 <= ifc->ifc_maxunit,
  393             ("%s: %s requested more units then allowed (%d > %d)",
  394             __func__, ifc->ifc_name, ifcs->ifcs_minifs,
  395             ifc->ifc_maxunit + 1));
  396 
  397         for (unit = 0; unit < ifcs->ifcs_minifs; unit++) {
  398                 snprintf(name, IFNAMSIZ, "%s%d", ifc->ifc_name, unit);
  399                 err = (*ifc->ifc_create)(ifc, name, IFNAMSIZ);
  400                 KASSERT(err == 0,
  401                     ("%s: failed to create required interface %s",
  402                     __func__, name));
  403         }
  404 }
  405 
  406 int
  407 ifc_simple_match(struct if_clone *ifc, const char *name)
  408 {
  409         const char *cp;
  410         int i;
  411         
  412         /* Match the name */
  413         for (cp = name, i = 0; i < strlen(ifc->ifc_name); i++, cp++) {
  414                 if (ifc->ifc_name[i] != *cp)
  415                         return (0);
  416         }
  417 
  418         /* Make sure there's a unit number or nothing after the name */
  419         for (; *cp != '\0'; cp++) {
  420                 if (*cp < '' || *cp > '9')
  421                         return (0);
  422         }
  423 
  424         return (1);
  425 }
  426 
  427 int
  428 ifc_simple_create(struct if_clone *ifc, char *name, size_t len)
  429 {
  430         char *dp;
  431         int wildcard;
  432         int unit;
  433         int err;
  434         struct ifc_simple_data *ifcs = ifc->ifc_data;
  435 
  436         err = ifc_name2unit(name, &unit);
  437         if (err != 0)
  438                 return (err);
  439 
  440         wildcard = (unit < 0);
  441 
  442         err = ifc_alloc_unit(ifc, &unit);
  443         if (err != 0)
  444                 return (err);
  445 
  446         err = ifcs->ifcs_create(ifc, unit);
  447         if (err != 0) {
  448                 ifc_free_unit(ifc, unit);
  449                 return (err);
  450         }
  451 
  452         /* In the wildcard case, we need to update the name. */
  453         if (wildcard) {
  454                 for (dp = name; *dp != '\0'; dp++);
  455                 if (snprintf(dp, len - (dp-name), "%d", unit) >
  456                     len - (dp-name) - 1) {
  457                         /*
  458                          * This can only be a programmer error and
  459                          * there's no straightforward way to recover if
  460                          * it happens.
  461                          */
  462                         panic("if_clone_create(): interface name too long");
  463                 }
  464 
  465         }
  466 
  467         return (0);
  468 }
  469 
  470 int
  471 ifc_simple_destroy(struct if_clone *ifc, struct ifnet *ifp)
  472 {
  473         int unit;
  474         struct ifc_simple_data *ifcs = ifc->ifc_data;
  475 
  476         unit = ifp->if_dunit;
  477 
  478         if (unit < ifcs->ifcs_minifs) 
  479                 return (EINVAL);
  480 
  481         ifcs->ifcs_destroy(ifp);
  482 
  483         ifc_free_unit(ifc, unit);
  484 
  485         return (0);
  486 }
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FreeBSD/Linux Kernel Cross Reference sys/net/if_clone.c

FreeBSD/Linux Kernel Cross Reference
sys/net/if_clone.c
