2 /* $NetBSD: pfil.c,v 1.20 2001/11/12 23:49:46 lukem Exp $ */
5 * Copyright (c) 1996 Matthew R. Green
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
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.
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
32 #include <sys/param.h>
33 #include <sys/kernel.h>
34 #include <sys/errno.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>
43 #include <sys/mutex.h>
45 #include <sys/queue.h>
50 static struct mtx pfil_global_lock;
52 MTX_SYSINIT(pfil_heads_lock, &pfil_global_lock, "pfil_head_list lock",
55 static struct packet_filter_hook *pfil_chain_get(int, struct pfil_head *);
56 static int pfil_chain_add(pfil_chain_t *, struct packet_filter_hook *, int);
57 static int pfil_chain_remove(pfil_chain_t *, pfil_func_t, void *);
59 LIST_HEAD(pfilheadhead, pfil_head);
60 VNET_DEFINE(struct pfilheadhead, pfil_head_list);
61 #define V_pfil_head_list VNET(pfil_head_list)
62 VNET_DEFINE(struct rmlock, pfil_lock);
63 #define V_pfil_lock VNET(pfil_lock)
66 * pfil_run_hooks() runs the specified packet filter hook chain.
69 pfil_run_hooks(struct pfil_head *ph, struct mbuf **mp, struct ifnet *ifp,
70 int dir, struct inpcb *inp)
72 struct rm_priotracker rmpt;
73 struct packet_filter_hook *pfh;
77 PFIL_RLOCK(ph, &rmpt);
78 KASSERT(ph->ph_nhooks >= 0, ("Pfil hook count dropped < 0"));
79 for (pfh = pfil_chain_get(dir, ph); pfh != NULL;
80 pfh = TAILQ_NEXT(pfh, pfil_chain)) {
81 if (pfh->pfil_func != NULL) {
82 rv = (*pfh->pfil_func)(pfh->pfil_arg, &m, ifp, dir,
84 if (rv != 0 || m == NULL)
88 PFIL_RUNLOCK(ph, &rmpt);
93 static struct packet_filter_hook *
94 pfil_chain_get(int dir, struct pfil_head *ph)
98 return (TAILQ_FIRST(&ph->ph_in));
99 else if (dir == PFIL_OUT)
100 return (TAILQ_FIRST(&ph->ph_out));
106 * pfil_try_rlock() acquires rm reader lock for specified head
107 * if this is immediately possible.
110 pfil_try_rlock(struct pfil_head *ph, struct rm_priotracker *tracker)
113 return (PFIL_TRY_RLOCK(ph, tracker));
117 * pfil_rlock() acquires rm reader lock for specified head.
120 pfil_rlock(struct pfil_head *ph, struct rm_priotracker *tracker)
123 PFIL_RLOCK(ph, tracker);
127 * pfil_runlock() releases reader lock for specified head.
130 pfil_runlock(struct pfil_head *ph, struct rm_priotracker *tracker)
133 PFIL_RUNLOCK(ph, tracker);
137 * pfil_wlock() acquires writer lock for specified head.
140 pfil_wlock(struct pfil_head *ph)
147 * pfil_wunlock() releases writer lock for specified head.
150 pfil_wunlock(struct pfil_head *ph)
157 * pfil_wowned() returns a non-zero value if the current thread owns
161 pfil_wowned(struct pfil_head *ph)
164 return (PFIL_WOWNED(ph));
168 * pfil_head_register() registers a pfil_head with the packet filter hook
172 pfil_head_register(struct pfil_head *ph)
174 struct pfil_head *lph;
176 PFIL_HEADLIST_LOCK();
177 LIST_FOREACH(lph, &V_pfil_head_list, ph_list) {
178 if (ph->ph_type == lph->ph_type &&
179 ph->ph_un.phu_val == lph->ph_un.phu_val) {
180 PFIL_HEADLIST_UNLOCK();
186 TAILQ_INIT(&ph->ph_in);
187 TAILQ_INIT(&ph->ph_out);
188 LIST_INSERT_HEAD(&V_pfil_head_list, ph, ph_list);
189 PFIL_HEADLIST_UNLOCK();
194 * pfil_head_unregister() removes a pfil_head from the packet filter hook
195 * mechanism. The producer of the hook promises that all outstanding
196 * invocations of the hook have completed before it unregisters the hook.
199 pfil_head_unregister(struct pfil_head *ph)
201 struct packet_filter_hook *pfh, *pfnext;
203 PFIL_HEADLIST_LOCK();
204 LIST_REMOVE(ph, ph_list);
205 PFIL_HEADLIST_UNLOCK();
206 TAILQ_FOREACH_SAFE(pfh, &ph->ph_in, pfil_chain, pfnext)
208 TAILQ_FOREACH_SAFE(pfh, &ph->ph_out, pfil_chain, pfnext)
210 PFIL_LOCK_DESTROY(ph);
215 * pfil_head_get() returns the pfil_head for a given key/dlt.
218 pfil_head_get(int type, u_long val)
220 struct pfil_head *ph;
222 PFIL_HEADLIST_LOCK();
223 LIST_FOREACH(ph, &V_pfil_head_list, ph_list)
224 if (ph->ph_type == type && ph->ph_un.phu_val == val)
226 PFIL_HEADLIST_UNLOCK();
231 * pfil_add_hook() adds a function to the packet filter hook. the
233 * PFIL_IN call me on incoming packets
234 * PFIL_OUT call me on outgoing packets
235 * PFIL_ALL call me on all of the above
236 * PFIL_WAITOK OK to call malloc with M_WAITOK.
239 pfil_add_hook(pfil_func_t func, void *arg, int flags, struct pfil_head *ph)
241 struct packet_filter_hook *pfh1 = NULL;
242 struct packet_filter_hook *pfh2 = NULL;
245 if (flags & PFIL_IN) {
246 pfh1 = (struct packet_filter_hook *)malloc(sizeof(*pfh1),
247 M_IFADDR, (flags & PFIL_WAITOK) ? M_WAITOK : M_NOWAIT);
253 if (flags & PFIL_OUT) {
254 pfh2 = (struct packet_filter_hook *)malloc(sizeof(*pfh1),
255 M_IFADDR, (flags & PFIL_WAITOK) ? M_WAITOK : M_NOWAIT);
262 if (flags & PFIL_IN) {
263 pfh1->pfil_func = func;
264 pfh1->pfil_arg = arg;
265 err = pfil_chain_add(&ph->ph_in, pfh1, flags & ~PFIL_OUT);
270 if (flags & PFIL_OUT) {
271 pfh2->pfil_func = func;
272 pfh2->pfil_arg = arg;
273 err = pfil_chain_add(&ph->ph_out, pfh2, flags & ~PFIL_IN);
276 pfil_chain_remove(&ph->ph_in, func, arg);
287 free(pfh1, M_IFADDR);
289 free(pfh2, M_IFADDR);
294 * pfil_remove_hook removes a specific function from the packet filter hook
298 pfil_remove_hook(pfil_func_t func, void *arg, int flags, struct pfil_head *ph)
303 if (flags & PFIL_IN) {
304 err = pfil_chain_remove(&ph->ph_in, func, arg);
308 if ((err == 0) && (flags & PFIL_OUT)) {
309 err = pfil_chain_remove(&ph->ph_out, func, arg);
318 * Internal: Add a new pfil hook into a hook chain.
321 pfil_chain_add(pfil_chain_t *chain, struct packet_filter_hook *pfh1, int flags)
323 struct packet_filter_hook *pfh;
326 * First make sure the hook is not already there.
328 TAILQ_FOREACH(pfh, chain, pfil_chain)
329 if (pfh->pfil_func == pfh1->pfil_func &&
330 pfh->pfil_arg == pfh1->pfil_arg)
334 * Insert the input list in reverse order of the output list so that
335 * the same path is followed in or out of the kernel.
338 TAILQ_INSERT_HEAD(chain, pfh1, pfil_chain);
340 TAILQ_INSERT_TAIL(chain, pfh1, pfil_chain);
345 * Internal: Remove a pfil hook from a hook chain.
348 pfil_chain_remove(pfil_chain_t *chain, pfil_func_t func, void *arg)
350 struct packet_filter_hook *pfh;
352 TAILQ_FOREACH(pfh, chain, pfil_chain)
353 if (pfh->pfil_func == func && pfh->pfil_arg == arg) {
354 TAILQ_REMOVE(chain, pfh, pfil_chain);
362 * Stuff that must be initialized for every instance (including the first of
366 vnet_pfil_init(const void *unused)
369 LIST_INIT(&V_pfil_head_list);
370 PFIL_LOCK_INIT_REAL(&V_pfil_lock, "shared");
375 * Called for the removal of each instance.
378 vnet_pfil_uninit(const void *unused)
381 KASSERT(LIST_EMPTY(&V_pfil_head_list),
382 ("%s: pfil_head_list %p not empty", __func__, &V_pfil_head_list));
383 PFIL_LOCK_DESTROY_REAL(&V_pfil_lock);
387 /* Define startup order. */
388 #define PFIL_SYSINIT_ORDER SI_SUB_PROTO_BEGIN
389 #define PFIL_MODEVENT_ORDER (SI_ORDER_FIRST) /* On boot slot in here. */
390 #define PFIL_VNET_ORDER (PFIL_MODEVENT_ORDER + 2) /* Later still. */
395 * VNET_SYSINIT is called for each existing vnet and each new vnet.
397 VNET_SYSINIT(vnet_pfil_init, PFIL_SYSINIT_ORDER, PFIL_VNET_ORDER,
398 vnet_pfil_init, NULL);
401 * Closing up shop. These are done in REVERSE ORDER. Not called on reboot.
403 * VNET_SYSUNINIT is called for each exiting vnet as it exits.
405 VNET_SYSUNINIT(vnet_pfil_uninit, PFIL_SYSINIT_ORDER, PFIL_VNET_ORDER,
406 vnet_pfil_uninit, NULL);