pfil.c

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    1 /*      $FreeBSD: releng/8.4/sys/net/pfil.c 203605 2010-02-07 09:00:22Z julian $ */
    2 /*      $NetBSD: pfil.c,v 1.20 2001/11/12 23:49:46 lukem Exp $  */
    3 
    4 /*-
    5  * Copyright (c) 1996 Matthew R. Green
    6  * All rights reserved.
    7  *
    8  * Redistribution and use in source and binary forms, with or without
    9  * modification, are permitted provided that the following conditions
   10  * are met:
   11  * 1. Redistributions of source code must retain the above copyright
   12  *    notice, this list of conditions and the following disclaimer.
   13  * 2. Redistributions in binary form must reproduce the above copyright
   14  *    notice, this list of conditions and the following disclaimer in the
   15  *    documentation and/or other materials provided with the distribution.
   16  * 3. The name of the author may not be used to endorse or promote products
   17  *    derived from this software without specific prior written permission.
   18  *
   19  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
   20  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
   21  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
   22  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
   23  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
   24  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
   25  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
   26  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
   27  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   29  * SUCH DAMAGE.
   30  */
   31 
   32 #include <sys/param.h>
   33 #include <sys/kernel.h>
   34 #include <sys/errno.h>
   35 #include <sys/lock.h>
   36 #include <sys/malloc.h>
   37 #include <sys/rmlock.h>
   38 #include <sys/socket.h>
   39 #include <sys/socketvar.h>
   40 #include <sys/systm.h>
   41 #include <sys/condvar.h>
   42 #include <sys/lock.h>
   43 #include <sys/mutex.h>
   44 #include <sys/proc.h>
   45 #include <sys/queue.h>
   46 
   47 #include <net/if.h>
   48 #include <net/pfil.h>
   49 
   50 static struct mtx pfil_global_lock;
   51 
   52 MTX_SYSINIT(pfil_heads_lock, &pfil_global_lock, "pfil_head_list lock",
   53   MTX_DEF);
   54 
   55 static int pfil_list_add(pfil_list_t *, struct packet_filter_hook *, int);
   56 
   57 static int pfil_list_remove(pfil_list_t *,
   58     int (*)(void *, struct mbuf **, struct ifnet *, int, struct inpcb *),
   59     void *);
   60 
   61 LIST_HEAD(pfilheadhead, pfil_head);
   62 VNET_DEFINE(struct pfilheadhead, pfil_head_list);
   63 #define V_pfil_head_list        VNET(pfil_head_list)
   64 
   65 /*
   66  * pfil_run_hooks() runs the specified packet filter hooks.
   67  */
   68 int
   69 pfil_run_hooks(struct pfil_head *ph, struct mbuf **mp, struct ifnet *ifp,
   70     int dir, struct inpcb *inp)
   71 {
   72         struct rm_priotracker rmpt;
   73         struct packet_filter_hook *pfh;
   74         struct mbuf *m = *mp;
   75         int rv = 0;
   76 
   77         PFIL_RLOCK(ph, &rmpt);
   78         KASSERT(ph->ph_nhooks >= 0, ("Pfil hook count dropped < 0"));
   79         for (pfh = pfil_hook_get(dir, ph); pfh != NULL;
   80              pfh = TAILQ_NEXT(pfh, pfil_link)) {
   81                 if (pfh->pfil_func != NULL) {
   82                         rv = (*pfh->pfil_func)(pfh->pfil_arg, &m, ifp, dir,
   83                             inp);
   84                         if (rv != 0 || m == NULL)
   85                                 break;
   86                 }
   87         }
   88         PFIL_RUNLOCK(ph, &rmpt);
   89         *mp = m;
   90         return (rv);
   91 }
   92 
   93 /*
   94  * pfil_head_register() registers a pfil_head with the packet filter hook
   95  * mechanism.
   96  */
   97 int
   98 pfil_head_register(struct pfil_head *ph)
   99 {
  100         struct pfil_head *lph;
  101 
  102         PFIL_LIST_LOCK();
  103         LIST_FOREACH(lph, &V_pfil_head_list, ph_list) {
  104                 if (ph->ph_type == lph->ph_type &&
  105                     ph->ph_un.phu_val == lph->ph_un.phu_val) {
  106                         PFIL_LIST_UNLOCK();
  107                         return (EEXIST);
  108                 }
  109         }
  110         PFIL_LOCK_INIT(ph);
  111         ph->ph_nhooks = 0;
  112         TAILQ_INIT(&ph->ph_in);
  113         TAILQ_INIT(&ph->ph_out);
  114         LIST_INSERT_HEAD(&V_pfil_head_list, ph, ph_list);
  115         PFIL_LIST_UNLOCK();
  116         return (0);
  117 }
  118 
  119 /*
  120  * pfil_head_unregister() removes a pfil_head from the packet filter hook
  121  * mechanism.  The producer of the hook promises that all outstanding
  122  * invocations of the hook have completed before it unregisters the hook.
  123  */
  124 int
  125 pfil_head_unregister(struct pfil_head *ph)
  126 {
  127         struct packet_filter_hook *pfh, *pfnext;
  128                 
  129         PFIL_LIST_LOCK();
  130         LIST_REMOVE(ph, ph_list);
  131         PFIL_LIST_UNLOCK();
  132         TAILQ_FOREACH_SAFE(pfh, &ph->ph_in, pfil_link, pfnext)
  133                 free(pfh, M_IFADDR);
  134         TAILQ_FOREACH_SAFE(pfh, &ph->ph_out, pfil_link, pfnext)
  135                 free(pfh, M_IFADDR);
  136         PFIL_LOCK_DESTROY(ph);
  137         return (0);
  138 }
  139 
  140 /*
  141  * pfil_head_get() returns the pfil_head for a given key/dlt.
  142  */
  143 struct pfil_head *
  144 pfil_head_get(int type, u_long val)
  145 {
  146         struct pfil_head *ph;
  147 
  148         PFIL_LIST_LOCK();
  149         LIST_FOREACH(ph, &V_pfil_head_list, ph_list)
  150                 if (ph->ph_type == type && ph->ph_un.phu_val == val)
  151                         break;
  152         PFIL_LIST_UNLOCK();
  153         return (ph);
  154 }
  155 
  156 /*
  157  * pfil_add_hook() adds a function to the packet filter hook.  the
  158  * flags are:
  159  *      PFIL_IN         call me on incoming packets
  160  *      PFIL_OUT        call me on outgoing packets
  161  *      PFIL_ALL        call me on all of the above
  162  *      PFIL_WAITOK     OK to call malloc with M_WAITOK.
  163  */
  164 int
  165 pfil_add_hook(int (*func)(void *, struct mbuf **, struct ifnet *, int,
  166   struct inpcb *), void *arg, int flags, struct pfil_head *ph)
  167 {
  168         struct packet_filter_hook *pfh1 = NULL;
  169         struct packet_filter_hook *pfh2 = NULL;
  170         int err;
  171 
  172         if (flags & PFIL_IN) {
  173                 pfh1 = (struct packet_filter_hook *)malloc(sizeof(*pfh1), 
  174                     M_IFADDR, (flags & PFIL_WAITOK) ? M_WAITOK : M_NOWAIT);
  175                 if (pfh1 == NULL) {
  176                         err = ENOMEM;
  177                         goto error;
  178                 }
  179         }
  180         if (flags & PFIL_OUT) {
  181                 pfh2 = (struct packet_filter_hook *)malloc(sizeof(*pfh1),
  182                     M_IFADDR, (flags & PFIL_WAITOK) ? M_WAITOK : M_NOWAIT);
  183                 if (pfh2 == NULL) {
  184                         err = ENOMEM;
  185                         goto error;
  186                 }
  187         }
  188         PFIL_WLOCK(ph);
  189         if (flags & PFIL_IN) {
  190                 pfh1->pfil_func = func;
  191                 pfh1->pfil_arg = arg;
  192                 err = pfil_list_add(&ph->ph_in, pfh1, flags & ~PFIL_OUT);
  193                 if (err)
  194                         goto locked_error;
  195                 ph->ph_nhooks++;
  196         }
  197         if (flags & PFIL_OUT) {
  198                 pfh2->pfil_func = func;
  199                 pfh2->pfil_arg = arg;
  200                 err = pfil_list_add(&ph->ph_out, pfh2, flags & ~PFIL_IN);
  201                 if (err) {
  202                         if (flags & PFIL_IN)
  203                                 pfil_list_remove(&ph->ph_in, func, arg);
  204                         goto locked_error;
  205                 }
  206                 ph->ph_nhooks++;
  207         }
  208         PFIL_WUNLOCK(ph);
  209         return (0);
  210 locked_error:
  211         PFIL_WUNLOCK(ph);
  212 error:
  213         if (pfh1 != NULL)
  214                 free(pfh1, M_IFADDR);
  215         if (pfh2 != NULL)
  216                 free(pfh2, M_IFADDR);
  217         return (err);
  218 }
  219 
  220 /*
  221  * pfil_remove_hook removes a specific function from the packet filter hook
  222  * list.
  223  */
  224 int
  225 pfil_remove_hook(int (*func)(void *, struct mbuf **, struct ifnet *, int,
  226     struct inpcb *), void *arg, int flags, struct pfil_head *ph)
  227 {
  228         int err = 0;
  229 
  230         PFIL_WLOCK(ph);
  231         if (flags & PFIL_IN) {
  232                 err = pfil_list_remove(&ph->ph_in, func, arg);
  233                 if (err == 0)
  234                         ph->ph_nhooks--;
  235         }
  236         if ((err == 0) && (flags & PFIL_OUT)) {
  237                 err = pfil_list_remove(&ph->ph_out, func, arg);
  238                 if (err == 0)
  239                         ph->ph_nhooks--;
  240         }
  241         PFIL_WUNLOCK(ph);
  242         return (err);
  243 }
  244 
  245 static int
  246 pfil_list_add(pfil_list_t *list, struct packet_filter_hook *pfh1, int flags)
  247 {
  248         struct packet_filter_hook *pfh;
  249 
  250         /*
  251          * First make sure the hook is not already there.
  252          */
  253         TAILQ_FOREACH(pfh, list, pfil_link)
  254                 if (pfh->pfil_func == pfh1->pfil_func &&
  255                     pfh->pfil_arg == pfh1->pfil_arg)
  256                         return (EEXIST);
  257 
  258         /*
  259          * Insert the input list in reverse order of the output list so that
  260          * the same path is followed in or out of the kernel.
  261          */
  262         if (flags & PFIL_IN)
  263                 TAILQ_INSERT_HEAD(list, pfh1, pfil_link);
  264         else
  265                 TAILQ_INSERT_TAIL(list, pfh1, pfil_link);
  266         return (0);
  267 }
  268 
  269 /*
  270  * pfil_list_remove is an internal function that takes a function off the
  271  * specified list.
  272  */
  273 static int
  274 pfil_list_remove(pfil_list_t *list,
  275     int (*func)(void *, struct mbuf **, struct ifnet *, int, struct inpcb *),
  276     void *arg)
  277 {
  278         struct packet_filter_hook *pfh;
  279 
  280         TAILQ_FOREACH(pfh, list, pfil_link)
  281                 if (pfh->pfil_func == func && pfh->pfil_arg == arg) {
  282                         TAILQ_REMOVE(list, pfh, pfil_link);
  283                         free(pfh, M_IFADDR);
  284                         return (0);
  285                 }
  286         return (ENOENT);
  287 }
  288 
  289 /****************
  290  * Stuff that must be initialized for every instance
  291  * (including the first of course).
  292  */
  293 static int
  294 vnet_pfil_init(const void *unused)
  295 {
  296         LIST_INIT(&V_pfil_head_list);
  297         return (0);
  298 }
  299 
  300 /***********************
  301  * Called for the removal of each instance.
  302  */
  303 static int
  304 vnet_pfil_uninit(const void *unused)
  305 {
  306         /*  XXX should panic if list is not empty */
  307         return 0;
  308 }
  309 
  310 /* Define startup order. */
  311 #define PFIL_SYSINIT_ORDER      SI_SUB_PROTO_BEGIN
  312 #define PFIL_MODEVENT_ORDER     (SI_ORDER_FIRST) /* On boot slot in here. */
  313 #define PFIL_VNET_ORDER         (PFIL_MODEVENT_ORDER + 2) /* Later still. */
  314 
  315 /*
  316  * Starting up. 
  317  * VNET_SYSINIT is called for each existing vnet and each new vnet.
  318  */
  319 VNET_SYSINIT(vnet_pfil_init, PFIL_SYSINIT_ORDER, PFIL_VNET_ORDER,
  320             vnet_pfil_init, NULL);
  321  
  322 /*
  323  * Closing up shop. These are done in REVERSE ORDER, 
  324  * Not called on reboot.
  325  * VNET_SYSUNINIT is called for each exiting vnet as it exits.
  326  */
  327 VNET_SYSUNINIT(vnet_pfil_uninit, PFIL_SYSINIT_ORDER, PFIL_VNET_ORDER,
  328             vnet_pfil_uninit, NULL);
  329
Cache object: 9299379067b1440b08937633646dd9ba
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FreeBSD/Linux Kernel Cross Reference sys/net/pfil.c

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