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 int pfil_list_add(pfil_list_t *, struct packet_filter_hook *, int);
57 static int pfil_list_remove(pfil_list_t *,
58 int (*)(void *, struct mbuf **, struct ifnet *, int, struct inpcb *),
61 LIST_HEAD(, pfil_head) pfil_head_list =
62 LIST_HEAD_INITIALIZER(&pfil_head_list);
65 * pfil_run_hooks() runs the specified packet filter hooks.
68 pfil_run_hooks(struct pfil_head *ph, struct mbuf **mp, struct ifnet *ifp,
69 int dir, struct inpcb *inp)
71 struct rm_priotracker rmpt;
72 struct packet_filter_hook *pfh;
76 PFIL_RLOCK(ph, &rmpt);
77 KASSERT(ph->ph_nhooks >= 0, ("Pfil hook count dropped < 0"));
78 for (pfh = pfil_hook_get(dir, ph); pfh != NULL;
79 pfh = TAILQ_NEXT(pfh, pfil_link)) {
80 if (pfh->pfil_func != NULL) {
81 rv = (*pfh->pfil_func)(pfh->pfil_arg, &m, ifp, dir,
83 if (rv != 0 || m == NULL)
87 PFIL_RUNLOCK(ph, &rmpt);
93 * pfil_head_register() registers a pfil_head with the packet filter hook
97 pfil_head_register(struct pfil_head *ph)
99 struct pfil_head *lph;
102 LIST_FOREACH(lph, &pfil_head_list, ph_list) {
103 if (ph->ph_type == lph->ph_type &&
104 ph->ph_un.phu_val == lph->ph_un.phu_val) {
111 TAILQ_INIT(&ph->ph_in);
112 TAILQ_INIT(&ph->ph_out);
113 LIST_INSERT_HEAD(&pfil_head_list, ph, ph_list);
119 * pfil_head_unregister() removes a pfil_head from the packet filter hook
120 * mechanism. The producer of the hook promises that all outstanding
121 * invocations of the hook have completed before it unregisters the hook.
124 pfil_head_unregister(struct pfil_head *ph)
126 struct packet_filter_hook *pfh, *pfnext;
129 LIST_REMOVE(ph, ph_list);
131 TAILQ_FOREACH_SAFE(pfh, &ph->ph_in, pfil_link, pfnext)
133 TAILQ_FOREACH_SAFE(pfh, &ph->ph_out, pfil_link, pfnext)
135 PFIL_LOCK_DESTROY(ph);
140 * pfil_head_get() returns the pfil_head for a given key/dlt.
143 pfil_head_get(int type, u_long val)
145 struct pfil_head *ph;
148 LIST_FOREACH(ph, &pfil_head_list, ph_list)
149 if (ph->ph_type == type && ph->ph_un.phu_val == val)
156 * pfil_add_hook() adds a function to the packet filter hook. the
158 * PFIL_IN call me on incoming packets
159 * PFIL_OUT call me on outgoing packets
160 * PFIL_ALL call me on all of the above
161 * PFIL_WAITOK OK to call malloc with M_WAITOK.
164 pfil_add_hook(int (*func)(void *, struct mbuf **, struct ifnet *, int,
165 struct inpcb *), void *arg, int flags, struct pfil_head *ph)
167 struct packet_filter_hook *pfh1 = NULL;
168 struct packet_filter_hook *pfh2 = NULL;
171 if (flags & PFIL_IN) {
172 pfh1 = (struct packet_filter_hook *)malloc(sizeof(*pfh1),
173 M_IFADDR, (flags & PFIL_WAITOK) ? M_WAITOK : M_NOWAIT);
179 if (flags & PFIL_OUT) {
180 pfh2 = (struct packet_filter_hook *)malloc(sizeof(*pfh1),
181 M_IFADDR, (flags & PFIL_WAITOK) ? M_WAITOK : M_NOWAIT);
188 if (flags & PFIL_IN) {
189 pfh1->pfil_func = func;
190 pfh1->pfil_arg = arg;
191 err = pfil_list_add(&ph->ph_in, pfh1, flags & ~PFIL_OUT);
196 if (flags & PFIL_OUT) {
197 pfh2->pfil_func = func;
198 pfh2->pfil_arg = arg;
199 err = pfil_list_add(&ph->ph_out, pfh2, flags & ~PFIL_IN);
202 pfil_list_remove(&ph->ph_in, func, arg);
213 free(pfh1, M_IFADDR);
215 free(pfh2, M_IFADDR);
220 * pfil_remove_hook removes a specific function from the packet filter hook
224 pfil_remove_hook(int (*func)(void *, struct mbuf **, struct ifnet *, int,
225 struct inpcb *), void *arg, int flags, struct pfil_head *ph)
230 if (flags & PFIL_IN) {
231 err = pfil_list_remove(&ph->ph_in, func, arg);
235 if ((err == 0) && (flags & PFIL_OUT)) {
236 err = pfil_list_remove(&ph->ph_out, func, arg);
245 pfil_list_add(pfil_list_t *list, struct packet_filter_hook *pfh1, int flags)
247 struct packet_filter_hook *pfh;
250 * First make sure the hook is not already there.
252 TAILQ_FOREACH(pfh, list, pfil_link)
253 if (pfh->pfil_func == pfh1->pfil_func &&
254 pfh->pfil_arg == pfh1->pfil_arg)
258 * Insert the input list in reverse order of the output list so that
259 * the same path is followed in or out of the kernel.
262 TAILQ_INSERT_HEAD(list, pfh1, pfil_link);
264 TAILQ_INSERT_TAIL(list, pfh1, pfil_link);
269 * pfil_list_remove is an internal function that takes a function off the
273 pfil_list_remove(pfil_list_t *list,
274 int (*func)(void *, struct mbuf **, struct ifnet *, int, struct inpcb *),
277 struct packet_filter_hook *pfh;
279 TAILQ_FOREACH(pfh, list, pfil_link)
280 if (pfh->pfil_func == func && pfh->pfil_arg == arg) {
281 TAILQ_REMOVE(list, pfh, pfil_link);