The Design and Implementation of the FreeBSD Operating System, Second Edition
Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)


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FreeBSD/Linux Kernel Cross Reference
sys/net/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  * $FreeBSD$
   31  */
   32 
   33 #include <sys/param.h>
   34 #include <sys/malloc.h>
   35 #include <sys/limits.h>
   36 #include <sys/lock.h>
   37 #include <sys/mutex.h>
   38 #include <sys/kernel.h>
   39 #include <sys/systm.h>
   40 #include <sys/types.h>
   41 #include <sys/socket.h>
   42 
   43 #include <net/if.h>
   44 #include <net/if_clone.h>
   45 #if 0
   46 #include <net/if_dl.h>
   47 #endif
   48 #include <net/if_types.h>
   49 #include <net/if_var.h>
   50 #include <net/radix.h>
   51 #include <net/route.h>
   52 
   53 static void     if_clone_free(struct if_clone *ifc);
   54 static int      if_clone_createif(struct if_clone *ifc, char *name, size_t len,
   55                     caddr_t params);
   56 static int      if_clone_destroyif(struct if_clone *ifc, struct ifnet *ifp);
   57 
   58 static struct mtx       if_cloners_mtx;
   59 static int              if_cloners_count;
   60 LIST_HEAD(, if_clone)   if_cloners = LIST_HEAD_INITIALIZER(if_cloners);
   61 
   62 #define IF_CLONERS_LOCK_INIT()          \
   63     mtx_init(&if_cloners_mtx, "if_cloners lock", NULL, MTX_DEF)
   64 #define IF_CLONERS_LOCK_ASSERT()        mtx_assert(&if_cloners_mtx, MA_OWNED)
   65 #define IF_CLONERS_LOCK()               mtx_lock(&if_cloners_mtx)
   66 #define IF_CLONERS_UNLOCK()             mtx_unlock(&if_cloners_mtx)
   67 
   68 #define IF_CLONE_LOCK_INIT(ifc)         \
   69     mtx_init(&(ifc)->ifc_mtx, "if_clone lock", NULL, MTX_DEF)
   70 #define IF_CLONE_LOCK_DESTROY(ifc)      mtx_destroy(&(ifc)->ifc_mtx)
   71 #define IF_CLONE_LOCK_ASSERT(ifc)       mtx_assert(&(ifc)->ifc_mtx, MA_OWNED)
   72 #define IF_CLONE_LOCK(ifc)              mtx_lock(&(ifc)->ifc_mtx)
   73 #define IF_CLONE_UNLOCK(ifc)            mtx_unlock(&(ifc)->ifc_mtx)
   74 
   75 #define IF_CLONE_ADDREF(ifc)                                            \
   76         do {                                                            \
   77                 IF_CLONE_LOCK(ifc);                                     \
   78                 IF_CLONE_ADDREF_LOCKED(ifc);                            \
   79                 IF_CLONE_UNLOCK(ifc);                                   \
   80         } while (0)
   81 #define IF_CLONE_ADDREF_LOCKED(ifc)                                     \
   82         do {                                                            \
   83                 IF_CLONE_LOCK_ASSERT(ifc);                              \
   84                 KASSERT((ifc)->ifc_refcnt >= 0,                         \
   85                     ("negative refcnt %ld", (ifc)->ifc_refcnt));        \
   86                 (ifc)->ifc_refcnt++;                                    \
   87         } while (0)
   88 #define IF_CLONE_REMREF(ifc)                                            \
   89         do {                                                            \
   90                 IF_CLONE_LOCK(ifc);                                     \
   91                 IF_CLONE_REMREF_LOCKED(ifc);                            \
   92         } while (0)
   93 #define IF_CLONE_REMREF_LOCKED(ifc)                                     \
   94         do {                                                            \
   95                 IF_CLONE_LOCK_ASSERT(ifc);                              \
   96                 KASSERT((ifc)->ifc_refcnt > 0,                          \
   97                     ("bogus refcnt %ld", (ifc)->ifc_refcnt));           \
   98                 if (--(ifc)->ifc_refcnt == 0) {                         \
   99                         IF_CLONE_UNLOCK(ifc);                           \
  100                         if_clone_free(ifc);                             \
  101                 } else {                                                \
  102                         /* silently free the lock */                    \
  103                         IF_CLONE_UNLOCK(ifc);                           \
  104                 }                                                       \
  105         } while (0)
  106 
  107 #define IFC_IFLIST_INSERT(_ifc, _ifp)                                   \
  108         LIST_INSERT_HEAD(&_ifc->ifc_iflist, _ifp, if_clones)
  109 #define IFC_IFLIST_REMOVE(_ifc, _ifp)                                   \
  110         LIST_REMOVE(_ifp, if_clones)
  111 
  112 static MALLOC_DEFINE(M_CLONE, "clone", "interface cloning framework");
  113 
  114 void
  115 if_clone_init(void)
  116 {
  117         IF_CLONERS_LOCK_INIT();
  118 }
  119 
  120 /*
  121  * Lookup and create a clone network interface.
  122  */
  123 int
  124 if_clone_create(char *name, size_t len, caddr_t params)
  125 {
  126         struct if_clone *ifc;
  127 
  128         /* Try to find an applicable cloner for this request */
  129         IF_CLONERS_LOCK();
  130         LIST_FOREACH(ifc, &if_cloners, ifc_list) {
  131                 if (ifc->ifc_match(ifc, name)) {
  132                         break;
  133                 }
  134         }
  135         IF_CLONERS_UNLOCK();
  136 
  137         if (ifc == NULL)
  138                 return (EINVAL);
  139 
  140         return (if_clone_createif(ifc, name, len, params));
  141 }
  142 
  143 /*
  144  * Create a clone network interface.
  145  */
  146 static int
  147 if_clone_createif(struct if_clone *ifc, char *name, size_t len, caddr_t params)
  148 {
  149         int err;
  150         struct ifnet *ifp;
  151 
  152         if (ifunit(name) != NULL)
  153                 return (EEXIST);
  154 
  155         err = (*ifc->ifc_create)(ifc, name, len, params);
  156         
  157         if (!err) {
  158                 ifp = ifunit(name);
  159                 if (ifp == NULL)
  160                         panic("%s: lookup failed for %s", __func__, name);
  161 
  162                 if_addgroup(ifp, ifc->ifc_name);
  163 
  164                 IF_CLONE_LOCK(ifc);
  165                 IFC_IFLIST_INSERT(ifc, ifp);
  166                 IF_CLONE_UNLOCK(ifc);
  167         }
  168 
  169         return (err);
  170 }
  171 
  172 /*
  173  * Lookup and destroy a clone network interface.
  174  */
  175 int
  176 if_clone_destroy(const char *name)
  177 {
  178         struct if_clone *ifc;
  179         struct ifnet *ifp;
  180 
  181         ifp = ifunit(name);
  182         if (ifp == NULL)
  183                 return (ENXIO);
  184 
  185         /* Find the cloner for this interface */
  186         IF_CLONERS_LOCK();
  187         LIST_FOREACH(ifc, &if_cloners, ifc_list) {
  188                 if (strcmp(ifc->ifc_name, ifp->if_dname) == 0) {
  189                         break;
  190                 }
  191         }
  192         IF_CLONERS_UNLOCK();
  193         if (ifc == NULL)
  194                 return (EINVAL);
  195 
  196         return (if_clone_destroyif(ifc, ifp));
  197 }
  198 
  199 /*
  200  * Destroy a clone network interface.
  201  */
  202 static int
  203 if_clone_destroyif(struct if_clone *ifc, struct ifnet *ifp)
  204 {
  205         int err;
  206 
  207         if (ifc->ifc_destroy == NULL) {
  208                 err = EOPNOTSUPP;
  209                 goto done;
  210         }
  211 
  212         IF_CLONE_LOCK(ifc);
  213         IFC_IFLIST_REMOVE(ifc, ifp);
  214         IF_CLONE_UNLOCK(ifc);
  215 
  216         if_delgroup(ifp, ifc->ifc_name);
  217 
  218         err =  (*ifc->ifc_destroy)(ifc, ifp);
  219 
  220         if (err != 0) {
  221                 if_addgroup(ifp, ifc->ifc_name);
  222 
  223                 IF_CLONE_LOCK(ifc);
  224                 IFC_IFLIST_INSERT(ifc, ifp);
  225                 IF_CLONE_UNLOCK(ifc);
  226         }
  227 
  228 done:
  229         return (err);
  230 }
  231 
  232 /*
  233  * Register a network interface cloner.
  234  */
  235 void
  236 if_clone_attach(struct if_clone *ifc)
  237 {
  238         int len, maxclone;
  239 
  240         /*
  241          * Compute bitmap size and allocate it.
  242          */
  243         maxclone = ifc->ifc_maxunit + 1;
  244         len = maxclone >> 3;
  245         if ((len << 3) < maxclone)
  246                 len++;
  247         ifc->ifc_units = malloc(len, M_CLONE, M_WAITOK | M_ZERO);
  248         ifc->ifc_bmlen = len;
  249         IF_CLONE_LOCK_INIT(ifc);
  250         IF_CLONE_ADDREF(ifc);
  251 
  252         IF_CLONERS_LOCK();
  253         LIST_INSERT_HEAD(&if_cloners, ifc, ifc_list);
  254         if_cloners_count++;
  255         IF_CLONERS_UNLOCK();
  256 
  257         LIST_INIT(&ifc->ifc_iflist);
  258 
  259         if (ifc->ifc_attach != NULL)
  260                 (*ifc->ifc_attach)(ifc);
  261         EVENTHANDLER_INVOKE(if_clone_event, ifc);
  262 }
  263 
  264 /*
  265  * Unregister a network interface cloner.
  266  */
  267 void
  268 if_clone_detach(struct if_clone *ifc)
  269 {
  270         struct ifc_simple_data *ifcs = ifc->ifc_data;
  271 
  272         IF_CLONERS_LOCK();
  273         LIST_REMOVE(ifc, ifc_list);
  274         if_cloners_count--;
  275         IF_CLONERS_UNLOCK();
  276 
  277         /* Allow all simples to be destroyed */
  278         if (ifc->ifc_attach == ifc_simple_attach)
  279                 ifcs->ifcs_minifs = 0;
  280 
  281         /* destroy all interfaces for this cloner */
  282         while (!LIST_EMPTY(&ifc->ifc_iflist))
  283                 if_clone_destroyif(ifc, LIST_FIRST(&ifc->ifc_iflist));
  284         
  285         IF_CLONE_REMREF(ifc);
  286 }
  287 
  288 static void
  289 if_clone_free(struct if_clone *ifc)
  290 {
  291         for (int bytoff = 0; bytoff < ifc->ifc_bmlen; bytoff++) {
  292                 KASSERT(ifc->ifc_units[bytoff] == 0x00,
  293                     ("ifc_units[%d] is not empty", bytoff));
  294         }
  295 
  296         KASSERT(LIST_EMPTY(&ifc->ifc_iflist),
  297             ("%s: ifc_iflist not empty", __func__));
  298 
  299         IF_CLONE_LOCK_DESTROY(ifc);
  300         free(ifc->ifc_units, M_CLONE);
  301 }
  302 
  303 /*
  304  * Provide list of interface cloners to userspace.
  305  */
  306 int
  307 if_clone_list(struct if_clonereq *ifcr)
  308 {
  309         char *buf, *dst, *outbuf = NULL;
  310         struct if_clone *ifc;
  311         int buf_count, count, err = 0;
  312 
  313         if (ifcr->ifcr_count < 0)
  314                 return (EINVAL);
  315 
  316         IF_CLONERS_LOCK();
  317         /*
  318          * Set our internal output buffer size.  We could end up not
  319          * reporting a cloner that is added between the unlock and lock
  320          * below, but that's not a major problem.  Not caping our
  321          * allocation to the number of cloners actually in the system
  322          * could be because that would let arbitrary users cause us to
  323          * allocate abritrary amounts of kernel memory.
  324          */
  325         buf_count = (if_cloners_count < ifcr->ifcr_count) ?
  326             if_cloners_count : ifcr->ifcr_count;
  327         IF_CLONERS_UNLOCK();
  328 
  329         outbuf = malloc(IFNAMSIZ*buf_count, M_CLONE, M_WAITOK | M_ZERO);
  330 
  331         IF_CLONERS_LOCK();
  332 
  333         ifcr->ifcr_total = if_cloners_count;
  334         if ((dst = ifcr->ifcr_buffer) == NULL) {
  335                 /* Just asking how many there are. */
  336                 goto done;
  337         }
  338         count = (if_cloners_count < buf_count) ?
  339             if_cloners_count : buf_count;
  340 
  341         for (ifc = LIST_FIRST(&if_cloners), buf = outbuf;
  342             ifc != NULL && count != 0;
  343             ifc = LIST_NEXT(ifc, ifc_list), count--, buf += IFNAMSIZ) {
  344                 strlcpy(buf, ifc->ifc_name, IFNAMSIZ);
  345         }
  346 
  347 done:
  348         IF_CLONERS_UNLOCK();
  349         if (err == 0)
  350                 err = copyout(outbuf, dst, buf_count*IFNAMSIZ);
  351         if (outbuf != NULL)
  352                 free(outbuf, M_CLONE);
  353         return (err);
  354 }
  355 
  356 /*
  357  * A utility function to extract unit numbers from interface names of
  358  * the form name###.
  359  *
  360  * Returns 0 on success and an error on failure.
  361  */
  362 int
  363 ifc_name2unit(const char *name, int *unit)
  364 {
  365         const char      *cp;
  366         int             cutoff = INT_MAX / 10;
  367         int             cutlim = INT_MAX % 10;
  368 
  369         for (cp = name; *cp != '\0' && (*cp < '' || *cp > '9'); cp++);
  370         if (*cp == '\0') {
  371                 *unit = -1;
  372         } else if (cp[0] == '' && cp[1] != '\0') {
  373                 /* Disallow leading zeroes. */
  374                 return (EINVAL);
  375         } else {
  376                 for (*unit = 0; *cp != '\0'; cp++) {
  377                         if (*cp < '' || *cp > '9') {
  378                                 /* Bogus unit number. */
  379                                 return (EINVAL);
  380                         }
  381                         if (*unit > cutoff ||
  382                             (*unit == cutoff && *cp - '' > cutlim))
  383                                 return (EINVAL);
  384                         *unit = (*unit * 10) + (*cp - '');
  385                 }
  386         }
  387 
  388         return (0);
  389 }
  390 
  391 int
  392 ifc_alloc_unit(struct if_clone *ifc, int *unit)
  393 {
  394         int wildcard, bytoff, bitoff;
  395         int err = 0;
  396 
  397         IF_CLONE_LOCK(ifc);
  398 
  399         bytoff = bitoff = 0;
  400         wildcard = (*unit < 0);
  401         /*
  402          * Find a free unit if none was given.
  403          */
  404         if (wildcard) {
  405                 while ((bytoff < ifc->ifc_bmlen)
  406                     && (ifc->ifc_units[bytoff] == 0xff))
  407                         bytoff++;
  408                 if (bytoff >= ifc->ifc_bmlen) {
  409                         err = ENOSPC;
  410                         goto done;
  411                 }
  412                 while ((ifc->ifc_units[bytoff] & (1 << bitoff)) != 0)
  413                         bitoff++;
  414                 *unit = (bytoff << 3) + bitoff;
  415         }
  416 
  417         if (*unit > ifc->ifc_maxunit) {
  418                 err = ENOSPC;
  419                 goto done;
  420         }
  421 
  422         if (!wildcard) {
  423                 bytoff = *unit >> 3;
  424                 bitoff = *unit - (bytoff << 3);
  425         }
  426 
  427         if((ifc->ifc_units[bytoff] & (1 << bitoff)) != 0) {
  428                 err = EEXIST;
  429                 goto done;
  430         }
  431         /*
  432          * Allocate the unit in the bitmap.
  433          */
  434         KASSERT((ifc->ifc_units[bytoff] & (1 << bitoff)) == 0,
  435             ("%s: bit is already set", __func__));
  436         ifc->ifc_units[bytoff] |= (1 << bitoff);
  437         IF_CLONE_ADDREF_LOCKED(ifc);
  438 
  439 done:
  440         IF_CLONE_UNLOCK(ifc);
  441         return (err);
  442 }
  443 
  444 void
  445 ifc_free_unit(struct if_clone *ifc, int unit)
  446 {
  447         int bytoff, bitoff;
  448 
  449 
  450         /*
  451          * Compute offset in the bitmap and deallocate the unit.
  452          */
  453         bytoff = unit >> 3;
  454         bitoff = unit - (bytoff << 3);
  455 
  456         IF_CLONE_LOCK(ifc);
  457         KASSERT((ifc->ifc_units[bytoff] & (1 << bitoff)) != 0,
  458             ("%s: bit is already cleared", __func__));
  459         ifc->ifc_units[bytoff] &= ~(1 << bitoff);
  460         IF_CLONE_REMREF_LOCKED(ifc);    /* releases lock */
  461 }
  462 
  463 void
  464 ifc_simple_attach(struct if_clone *ifc)
  465 {
  466         int err;
  467         int unit;
  468         char name[IFNAMSIZ];
  469         struct ifc_simple_data *ifcs = ifc->ifc_data;
  470 
  471         KASSERT(ifcs->ifcs_minifs - 1 <= ifc->ifc_maxunit,
  472             ("%s: %s requested more units than allowed (%d > %d)",
  473             __func__, ifc->ifc_name, ifcs->ifcs_minifs,
  474             ifc->ifc_maxunit + 1));
  475 
  476         for (unit = 0; unit < ifcs->ifcs_minifs; unit++) {
  477                 snprintf(name, IFNAMSIZ, "%s%d", ifc->ifc_name, unit);
  478                 err = if_clone_createif(ifc, name, IFNAMSIZ, NULL);
  479                 KASSERT(err == 0,
  480                     ("%s: failed to create required interface %s",
  481                     __func__, name));
  482         }
  483 }
  484 
  485 int
  486 ifc_simple_match(struct if_clone *ifc, const char *name)
  487 {
  488         const char *cp;
  489         int i;
  490         
  491         /* Match the name */
  492         for (cp = name, i = 0; i < strlen(ifc->ifc_name); i++, cp++) {
  493                 if (ifc->ifc_name[i] != *cp)
  494                         return (0);
  495         }
  496 
  497         /* Make sure there's a unit number or nothing after the name */
  498         for (; *cp != '\0'; cp++) {
  499                 if (*cp < '' || *cp > '9')
  500                         return (0);
  501         }
  502 
  503         return (1);
  504 }
  505 
  506 int
  507 ifc_simple_create(struct if_clone *ifc, char *name, size_t len, caddr_t params)
  508 {
  509         char *dp;
  510         int wildcard;
  511         int unit;
  512         int err;
  513         struct ifc_simple_data *ifcs = ifc->ifc_data;
  514 
  515         err = ifc_name2unit(name, &unit);
  516         if (err != 0)
  517                 return (err);
  518 
  519         wildcard = (unit < 0);
  520 
  521         err = ifc_alloc_unit(ifc, &unit);
  522         if (err != 0)
  523                 return (err);
  524 
  525         err = ifcs->ifcs_create(ifc, unit, params);
  526         if (err != 0) {
  527                 ifc_free_unit(ifc, unit);
  528                 return (err);
  529         }
  530 
  531         /* In the wildcard case, we need to update the name. */
  532         if (wildcard) {
  533                 for (dp = name; *dp != '\0'; dp++);
  534                 if (snprintf(dp, len - (dp-name), "%d", unit) >
  535                     len - (dp-name) - 1) {
  536                         /*
  537                          * This can only be a programmer error and
  538                          * there's no straightforward way to recover if
  539                          * it happens.
  540                          */
  541                         panic("if_clone_create(): interface name too long");
  542                 }
  543 
  544         }
  545 
  546         return (0);
  547 }
  548 
  549 int
  550 ifc_simple_destroy(struct if_clone *ifc, struct ifnet *ifp)
  551 {
  552         int unit;
  553         struct ifc_simple_data *ifcs = ifc->ifc_data;
  554 
  555         unit = ifp->if_dunit;
  556 
  557         if (unit < ifcs->ifcs_minifs) 
  558                 return (EINVAL);
  559 
  560         ifcs->ifcs_destroy(ifp);
  561 
  562         ifc_free_unit(ifc, unit);
  563 
  564         return (0);
  565 }

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