4 * Copyright (c) 1996 Matthew R. Green
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. The name of the author may not be used to endorse or promote products
16 * derived from this software without specific prior written permission.
18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
19 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
20 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
21 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
22 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
23 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
24 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
25 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
26 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 #include <sys/param.h>
32 #include <sys/errno.h>
33 #include <sys/malloc.h>
34 #include <sys/socket.h>
35 #include <sys/socketvar.h>
36 #include <sys/systm.h>
38 #include <sys/queue.h>
43 static void pfil_init __P((struct pfil_head *));
44 static int pfil_list_add(pfil_list_t *,
45 int (*) __P((void *, int, struct ifnet *, int, struct mbuf **)), int);
46 static int pfil_list_remove(pfil_list_t *,
47 int (*) __P((void *, int, struct ifnet *, int, struct mbuf **)));
54 TAILQ_INIT(&ph->ph_in);
55 TAILQ_INIT(&ph->ph_out);
60 * pfil_add_hook() adds a function to the packet filter hook. the
62 * PFIL_IN call me on incoming packets
63 * PFIL_OUT call me on outgoing packets
64 * PFIL_ALL call me on all of the above
65 * PFIL_WAITOK OK to call malloc with M_WAITOK.
68 pfil_add_hook(func, flags, ph)
69 int (*func) __P((void *, int, struct ifnet *, int,
80 err = pfil_list_add(&ph->ph_in, func, flags & ~PFIL_OUT);
84 err = pfil_list_add(&ph->ph_out, func, flags & ~PFIL_IN);
87 pfil_list_remove(&ph->ph_in, func);
94 pfil_list_add(list, func, flags)
96 int (*func) __P((void *, int, struct ifnet *, int,
100 struct packet_filter_hook *pfh;
102 pfh = (struct packet_filter_hook *)malloc(sizeof(*pfh), M_IFADDR,
103 flags & PFIL_WAITOK ? M_WAITOK : M_NOWAIT);
106 pfh->pfil_func = func;
108 * insert the input list in reverse order of the output list
109 * so that the same path is followed in or out of the kernel.
113 TAILQ_INSERT_HEAD(list, pfh, pfil_link);
115 TAILQ_INSERT_TAIL(list, pfh, pfil_link);
120 * pfil_remove_hook removes a specific function from the packet filter
124 pfil_remove_hook(func, flags, ph)
125 int (*func) __P((void *, int, struct ifnet *, int,
128 struct pfil_head *ph;
132 if (ph->ph_init == 0)
136 err = pfil_list_remove(&ph->ph_in, func);
137 if ((err == 0) && (flags & PFIL_OUT))
138 err = pfil_list_remove(&ph->ph_out, func);
143 * pfil_list_remove is an internal function that takes a function off the
147 pfil_list_remove(list, func)
149 int (*func) __P((void *, int, struct ifnet *, int,
152 struct packet_filter_hook *pfh;
154 for (pfh = list->tqh_first; pfh; pfh = pfh->pfil_link.tqe_next)
155 if (pfh->pfil_func == func) {
156 TAILQ_REMOVE(list, pfh, pfil_link);
163 struct packet_filter_hook *
164 pfil_hook_get(flag, ph)
166 struct pfil_head *ph;
168 if (ph->ph_init != 0)
171 return (ph->ph_in.tqh_first);
173 return (ph->ph_out.tqh_first);