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>
48 #include <net/if_var.h>
51 static struct mtx pfil_global_lock;
53 MTX_SYSINIT(pfil_heads_lock, &pfil_global_lock, "pfil_head_list lock",
56 static struct packet_filter_hook *pfil_chain_get(int, struct pfil_head *);
57 static int pfil_chain_add(pfil_chain_t *, struct packet_filter_hook *, int);
58 static int pfil_chain_remove(pfil_chain_t *, pfil_func_t, void *);
60 LIST_HEAD(pfilheadhead, pfil_head);
61 VNET_DEFINE(struct pfilheadhead, pfil_head_list);
62 #define V_pfil_head_list VNET(pfil_head_list)
63 VNET_DEFINE(struct rmlock, pfil_lock);
64 #define V_pfil_lock VNET(pfil_lock)
66 #define PFIL_LOCK_INIT_REAL(l, t) \
67 rm_init_flags(l, "PFil " t " rmlock", RM_RECURSE)
68 #define PFIL_LOCK_DESTROY_REAL(l) \
70 #define PFIL_LOCK_INIT(p) do { \
71 if ((p)->flags & PFIL_FLAG_PRIVATE_LOCK) { \
72 PFIL_LOCK_INIT_REAL(&(p)->ph_lock, "private"); \
73 (p)->ph_plock = &(p)->ph_lock; \
75 (p)->ph_plock = &V_pfil_lock; \
77 #define PFIL_LOCK_DESTROY(p) do { \
78 if ((p)->flags & PFIL_FLAG_PRIVATE_LOCK) \
79 PFIL_LOCK_DESTROY_REAL((p)->ph_plock); \
82 #define PFIL_TRY_RLOCK(p, t) rm_try_rlock((p)->ph_plock, (t))
83 #define PFIL_RLOCK(p, t) rm_rlock((p)->ph_plock, (t))
84 #define PFIL_WLOCK(p) rm_wlock((p)->ph_plock)
85 #define PFIL_RUNLOCK(p, t) rm_runlock((p)->ph_plock, (t))
86 #define PFIL_WUNLOCK(p) rm_wunlock((p)->ph_plock)
87 #define PFIL_WOWNED(p) rm_wowned((p)->ph_plock)
89 #define PFIL_HEADLIST_LOCK() mtx_lock(&pfil_global_lock)
90 #define PFIL_HEADLIST_UNLOCK() mtx_unlock(&pfil_global_lock)
93 * pfil_run_hooks() runs the specified packet filter hook chain.
96 pfil_run_hooks(struct pfil_head *ph, struct mbuf **mp, struct ifnet *ifp,
97 int dir, struct inpcb *inp)
99 struct rm_priotracker rmpt;
100 struct packet_filter_hook *pfh;
101 struct mbuf *m = *mp;
104 PFIL_RLOCK(ph, &rmpt);
105 KASSERT(ph->ph_nhooks >= 0, ("Pfil hook count dropped < 0"));
106 for (pfh = pfil_chain_get(dir, ph); pfh != NULL;
107 pfh = TAILQ_NEXT(pfh, pfil_chain)) {
108 if (pfh->pfil_func != NULL) {
109 rv = (*pfh->pfil_func)(pfh->pfil_arg, &m, ifp, dir,
111 if (rv != 0 || m == NULL)
115 PFIL_RUNLOCK(ph, &rmpt);
120 static struct packet_filter_hook *
121 pfil_chain_get(int dir, struct pfil_head *ph)
125 return (TAILQ_FIRST(&ph->ph_in));
126 else if (dir == PFIL_OUT)
127 return (TAILQ_FIRST(&ph->ph_out));
133 * pfil_try_rlock() acquires rm reader lock for specified head
134 * if this is immediately possible.
137 pfil_try_rlock(struct pfil_head *ph, struct rm_priotracker *tracker)
140 return (PFIL_TRY_RLOCK(ph, tracker));
144 * pfil_rlock() acquires rm reader lock for specified head.
147 pfil_rlock(struct pfil_head *ph, struct rm_priotracker *tracker)
150 PFIL_RLOCK(ph, tracker);
154 * pfil_runlock() releases reader lock for specified head.
157 pfil_runlock(struct pfil_head *ph, struct rm_priotracker *tracker)
160 PFIL_RUNLOCK(ph, tracker);
164 * pfil_wlock() acquires writer lock for specified head.
167 pfil_wlock(struct pfil_head *ph)
174 * pfil_wunlock() releases writer lock for specified head.
177 pfil_wunlock(struct pfil_head *ph)
184 * pfil_wowned() returns a non-zero value if the current thread owns
188 pfil_wowned(struct pfil_head *ph)
191 return (PFIL_WOWNED(ph));
195 * pfil_head_register() registers a pfil_head with the packet filter hook
199 pfil_head_register(struct pfil_head *ph)
201 struct pfil_head *lph;
203 PFIL_HEADLIST_LOCK();
204 LIST_FOREACH(lph, &V_pfil_head_list, ph_list) {
205 if (ph->ph_type == lph->ph_type &&
206 ph->ph_un.phu_val == lph->ph_un.phu_val) {
207 PFIL_HEADLIST_UNLOCK();
213 TAILQ_INIT(&ph->ph_in);
214 TAILQ_INIT(&ph->ph_out);
215 LIST_INSERT_HEAD(&V_pfil_head_list, ph, ph_list);
216 PFIL_HEADLIST_UNLOCK();
221 * pfil_head_unregister() removes a pfil_head from the packet filter hook
222 * mechanism. The producer of the hook promises that all outstanding
223 * invocations of the hook have completed before it unregisters the hook.
226 pfil_head_unregister(struct pfil_head *ph)
228 struct packet_filter_hook *pfh, *pfnext;
230 PFIL_HEADLIST_LOCK();
231 LIST_REMOVE(ph, ph_list);
232 PFIL_HEADLIST_UNLOCK();
233 TAILQ_FOREACH_SAFE(pfh, &ph->ph_in, pfil_chain, pfnext)
235 TAILQ_FOREACH_SAFE(pfh, &ph->ph_out, pfil_chain, pfnext)
237 PFIL_LOCK_DESTROY(ph);
242 * pfil_head_get() returns the pfil_head for a given key/dlt.
245 pfil_head_get(int type, u_long val)
247 struct pfil_head *ph;
249 PFIL_HEADLIST_LOCK();
250 LIST_FOREACH(ph, &V_pfil_head_list, ph_list)
251 if (ph->ph_type == type && ph->ph_un.phu_val == val)
253 PFIL_HEADLIST_UNLOCK();
258 * pfil_add_hook() adds a function to the packet filter hook. the
260 * PFIL_IN call me on incoming packets
261 * PFIL_OUT call me on outgoing packets
262 * PFIL_ALL call me on all of the above
263 * PFIL_WAITOK OK to call malloc with M_WAITOK.
266 pfil_add_hook(pfil_func_t func, void *arg, int flags, struct pfil_head *ph)
268 struct packet_filter_hook *pfh1 = NULL;
269 struct packet_filter_hook *pfh2 = NULL;
272 if (flags & PFIL_IN) {
273 pfh1 = (struct packet_filter_hook *)malloc(sizeof(*pfh1),
274 M_IFADDR, (flags & PFIL_WAITOK) ? M_WAITOK : M_NOWAIT);
280 if (flags & PFIL_OUT) {
281 pfh2 = (struct packet_filter_hook *)malloc(sizeof(*pfh1),
282 M_IFADDR, (flags & PFIL_WAITOK) ? M_WAITOK : M_NOWAIT);
289 if (flags & PFIL_IN) {
290 pfh1->pfil_func = func;
291 pfh1->pfil_arg = arg;
292 err = pfil_chain_add(&ph->ph_in, pfh1, flags & ~PFIL_OUT);
297 if (flags & PFIL_OUT) {
298 pfh2->pfil_func = func;
299 pfh2->pfil_arg = arg;
300 err = pfil_chain_add(&ph->ph_out, pfh2, flags & ~PFIL_IN);
303 pfil_chain_remove(&ph->ph_in, func, arg);
314 free(pfh1, M_IFADDR);
316 free(pfh2, M_IFADDR);
321 * pfil_remove_hook removes a specific function from the packet filter hook
325 pfil_remove_hook(pfil_func_t func, void *arg, int flags, struct pfil_head *ph)
330 if (flags & PFIL_IN) {
331 err = pfil_chain_remove(&ph->ph_in, func, arg);
335 if ((err == 0) && (flags & PFIL_OUT)) {
336 err = pfil_chain_remove(&ph->ph_out, func, arg);
345 * Internal: Add a new pfil hook into a hook chain.
348 pfil_chain_add(pfil_chain_t *chain, struct packet_filter_hook *pfh1, int flags)
350 struct packet_filter_hook *pfh;
353 * First make sure the hook is not already there.
355 TAILQ_FOREACH(pfh, chain, pfil_chain)
356 if (pfh->pfil_func == pfh1->pfil_func &&
357 pfh->pfil_arg == pfh1->pfil_arg)
361 * Insert the input list in reverse order of the output list so that
362 * the same path is followed in or out of the kernel.
365 TAILQ_INSERT_HEAD(chain, pfh1, pfil_chain);
367 TAILQ_INSERT_TAIL(chain, pfh1, pfil_chain);
372 * Internal: Remove a pfil hook from a hook chain.
375 pfil_chain_remove(pfil_chain_t *chain, pfil_func_t func, void *arg)
377 struct packet_filter_hook *pfh;
379 TAILQ_FOREACH(pfh, chain, pfil_chain)
380 if (pfh->pfil_func == func && pfh->pfil_arg == arg) {
381 TAILQ_REMOVE(chain, pfh, pfil_chain);
389 * Stuff that must be initialized for every instance (including the first of
393 vnet_pfil_init(const void *unused __unused)
396 LIST_INIT(&V_pfil_head_list);
397 PFIL_LOCK_INIT_REAL(&V_pfil_lock, "shared");
401 * Called for the removal of each instance.
404 vnet_pfil_uninit(const void *unused __unused)
407 KASSERT(LIST_EMPTY(&V_pfil_head_list),
408 ("%s: pfil_head_list %p not empty", __func__, &V_pfil_head_list));
409 PFIL_LOCK_DESTROY_REAL(&V_pfil_lock);
415 * VNET_SYSINIT is called for each existing vnet and each new vnet.
416 * Make sure the pfil bits are first before any possible subsystem which
417 * might piggyback on the SI_SUB_PROTO_PFIL.
419 VNET_SYSINIT(vnet_pfil_init, SI_SUB_PROTO_PFIL, SI_ORDER_FIRST,
420 vnet_pfil_init, NULL);
423 * Closing up shop. These are done in REVERSE ORDER. Not called on reboot.
425 * VNET_SYSUNINIT is called for each exiting vnet as it exits.
427 VNET_SYSUNINIT(vnet_pfil_uninit, SI_SUB_PROTO_PFIL, SI_ORDER_FIRST,
428 vnet_pfil_uninit, NULL);