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", MTX_DEF);
54 static int pfil_list_add(pfil_list_t *, struct packet_filter_hook *, int);
56 static int pfil_list_remove(pfil_list_t *,
57 int (*)(void *, struct mbuf **, struct ifnet *, int, struct inpcb *), void *);
59 LIST_HEAD(, pfil_head) pfil_head_list =
60 LIST_HEAD_INITIALIZER(&pfil_head_list);
63 * pfil_run_hooks() runs the specified packet filter hooks.
66 pfil_run_hooks(struct pfil_head *ph, struct mbuf **mp, struct ifnet *ifp,
67 int dir, struct inpcb *inp)
69 struct rm_priotracker rmpt;
70 struct packet_filter_hook *pfh;
74 PFIL_RLOCK(ph, &rmpt);
75 KASSERT(ph->ph_nhooks >= 0, ("Pfil hook count dropped < 0"));
76 for (pfh = pfil_hook_get(dir, ph); pfh != NULL;
77 pfh = TAILQ_NEXT(pfh, pfil_link)) {
78 if (pfh->pfil_func != NULL) {
79 rv = (*pfh->pfil_func)(pfh->pfil_arg, &m, ifp, dir, inp);
80 if (rv != 0 || m == NULL)
84 PFIL_RUNLOCK(ph, &rmpt);
91 * pfil_head_register() registers a pfil_head with the packet filter
95 pfil_head_register(struct pfil_head *ph)
97 struct pfil_head *lph;
100 LIST_FOREACH(lph, &pfil_head_list, ph_list)
101 if (ph->ph_type == lph->ph_type &&
102 ph->ph_un.phu_val == lph->ph_un.phu_val) {
112 TAILQ_INIT(&ph->ph_in);
113 TAILQ_INIT(&ph->ph_out);
116 LIST_INSERT_HEAD(&pfil_head_list, ph, ph_list);
125 * pfil_head_unregister() removes a pfil_head from the packet filter
129 pfil_head_unregister(struct pfil_head *ph)
131 struct packet_filter_hook *pfh, *pfnext;
135 * LIST_REMOVE is safe for unlocked pfil_heads in ph_list.
136 * No need to WLOCK all of them.
138 LIST_REMOVE(ph, ph_list);
143 TAILQ_FOREACH_SAFE(pfh, &ph->ph_in, pfil_link, pfnext)
145 TAILQ_FOREACH_SAFE(pfh, &ph->ph_out, pfil_link, pfnext)
147 PFIL_LOCK_DESTROY(ph);
153 * pfil_head_get() returns the pfil_head for a given key/dlt.
156 pfil_head_get(int type, u_long val)
158 struct pfil_head *ph;
161 LIST_FOREACH(ph, &pfil_head_list, ph_list)
162 if (ph->ph_type == type && ph->ph_un.phu_val == val)
170 * pfil_add_hook() adds a function to the packet filter hook. the
172 * PFIL_IN call me on incoming packets
173 * PFIL_OUT call me on outgoing packets
174 * PFIL_ALL call me on all of the above
175 * PFIL_WAITOK OK to call malloc with M_WAITOK.
178 pfil_add_hook(int (*func)(void *, struct mbuf **, struct ifnet *, int, struct inpcb *),
179 void *arg, int flags, struct pfil_head *ph)
181 struct packet_filter_hook *pfh1 = NULL;
182 struct packet_filter_hook *pfh2 = NULL;
186 if (flags & PFIL_IN) {
187 pfh1 = (struct packet_filter_hook *)malloc(sizeof(*pfh1),
188 M_IFADDR, (flags & PFIL_WAITOK) ? M_WAITOK : M_NOWAIT);
194 if (flags & PFIL_OUT) {
195 pfh2 = (struct packet_filter_hook *)malloc(sizeof(*pfh1),
196 M_IFADDR, (flags & PFIL_WAITOK) ? M_WAITOK : M_NOWAIT);
207 if (flags & PFIL_IN) {
208 pfh1->pfil_func = func;
209 pfh1->pfil_arg = arg;
210 err = pfil_list_add(&ph->ph_in, pfh1, flags & ~PFIL_OUT);
215 if (flags & PFIL_OUT) {
216 pfh2->pfil_func = func;
217 pfh2->pfil_arg = arg;
218 err = pfil_list_add(&ph->ph_out, pfh2, flags & ~PFIL_IN);
221 pfil_list_remove(&ph->ph_in, func, arg);
234 free(pfh1, M_IFADDR);
236 free(pfh2, M_IFADDR);
241 * pfil_remove_hook removes a specific function from the packet filter
245 pfil_remove_hook(int (*func)(void *, struct mbuf **, struct ifnet *, int, struct inpcb *),
246 void *arg, int flags, struct pfil_head *ph)
252 if (flags & PFIL_IN) {
253 err = pfil_list_remove(&ph->ph_in, func, arg);
257 if ((err == 0) && (flags & PFIL_OUT)) {
258 err = pfil_list_remove(&ph->ph_out, func, arg);
268 pfil_list_add(pfil_list_t *list, struct packet_filter_hook *pfh1, int flags)
270 struct packet_filter_hook *pfh;
273 * First make sure the hook is not already there.
275 TAILQ_FOREACH(pfh, list, pfil_link)
276 if (pfh->pfil_func == pfh1->pfil_func &&
277 pfh->pfil_arg == pfh1->pfil_arg)
280 * insert the input list in reverse order of the output list
281 * so that the same path is followed in or out of the kernel.
284 TAILQ_INSERT_HEAD(list, pfh1, pfil_link);
286 TAILQ_INSERT_TAIL(list, pfh1, pfil_link);
292 * pfil_list_remove is an internal function that takes a function off the
296 pfil_list_remove(pfil_list_t *list,
297 int (*func)(void *, struct mbuf **, struct ifnet *, int, struct inpcb *), void *arg)
299 struct packet_filter_hook *pfh;
301 TAILQ_FOREACH(pfh, list, pfil_link)
302 if (pfh->pfil_func == func && pfh->pfil_arg == arg) {
303 TAILQ_REMOVE(list, pfh, pfil_link);