Add the packet filtering files.
[dragonfly.git] / sys / net / pfil.c
CommitLineData
9e99d0a2
JR
1/* $NetBSD: pfil.c,v 1.20 2001/11/12 23:49:46 lukem Exp $ */
2/* $DragonFly: src/sys/net/pfil.c,v 1.1 2003/12/02 09:18:17 asmodai Exp $ */
3
4/*
5 * Copyright (c) 1996 Matthew R. Green
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
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.
18 *
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
29 * SUCH DAMAGE.
30 */
31
32#include <sys/param.h>
33#include <sys/errno.h>
34#include <sys/malloc.h>
35#include <sys/socket.h>
36#include <sys/socketvar.h>
37#include <sys/systm.h>
38#include <sys/proc.h>
39#include <sys/queue.h>
40
41#include <net/if.h>
42#include <net/pfil.h>
43
44static int pfil_list_add(pfil_list_t *,
45 int (*)(void *, struct mbuf **, struct ifnet *, int), void *, int);
46
47static int pfil_list_remove(pfil_list_t *,
48 int (*)(void *, struct mbuf **, struct ifnet *, int), void *);
49
50LIST_HEAD(, pfil_head) pfil_head_list =
51 LIST_HEAD_INITIALIZER(&pfil_head_list);
52
53/*
54 * pfil_run_hooks() runs the specified packet filter hooks.
55 */
56int
57pfil_run_hooks(struct pfil_head *ph, struct mbuf **mp, struct ifnet *ifp,
58 int dir)
59{
60 struct packet_filter_hook *pfh;
61 struct mbuf *m = *mp;
62 int rv = 0;
63
64 for (pfh = pfil_hook_get(dir, ph); pfh != NULL;
65 pfh = TAILQ_NEXT(pfh, pfil_link)) {
66 if (pfh->pfil_func != NULL) {
67 rv = (*pfh->pfil_func)(pfh->pfil_arg, &m, ifp, dir);
68 if (rv != 0 || m == NULL)
69 break;
70 }
71 }
72
73 *mp = m;
74 return (rv);
75}
76
77/*
78 * pfil_head_register() registers a pfil_head with the packet filter
79 * hook mechanism.
80 */
81int
82pfil_head_register(struct pfil_head *ph)
83{
84 struct pfil_head *lph;
85
86 for (lph = LIST_FIRST(&pfil_head_list); lph != NULL;
87 lph = LIST_NEXT(lph, ph_list)) {
88 if (ph->ph_type == lph->ph_type &&
89 ph->ph_un.phu_val == lph->ph_un.phu_val)
90 return EEXIST;
91 }
92
93 TAILQ_INIT(&ph->ph_in);
94 TAILQ_INIT(&ph->ph_out);
95
96 LIST_INSERT_HEAD(&pfil_head_list, ph, ph_list);
97
98 return (0);
99}
100
101/*
102 * pfil_head_unregister() removes a pfil_head from the packet filter
103 * hook mechanism.
104 */
105int
106pfil_head_unregister(struct pfil_head *pfh)
107{
108
109 LIST_REMOVE(pfh, ph_list);
110 return (0);
111}
112
113/*
114 * pfil_head_get() returns the pfil_head for a given key/dlt.
115 */
116struct pfil_head *
117pfil_head_get(int type, u_long val)
118{
119 struct pfil_head *ph;
120
121 for (ph = LIST_FIRST(&pfil_head_list); ph != NULL;
122 ph = LIST_NEXT(ph, ph_list)) {
123 if (ph->ph_type == type &&
124 ph->ph_un.phu_val == val)
125 break;
126 }
127
128 return (ph);
129}
130
131/*
132 * pfil_add_hook() adds a function to the packet filter hook. the
133 * flags are:
134 * PFIL_IN call me on incoming packets
135 * PFIL_OUT call me on outgoing packets
136 * PFIL_ALL call me on all of the above
137 * PFIL_WAITOK OK to call malloc with M_WAITOK.
138 */
139int
140pfil_add_hook(int (*func)(void *, struct mbuf **, struct ifnet *, int),
141 void *arg, int flags, struct pfil_head *ph)
142{
143 int err = 0;
144
145 if (flags & PFIL_IN) {
146 err = pfil_list_add(&ph->ph_in, func, arg, flags & ~PFIL_OUT);
147 if (err)
148 return err;
149 }
150 if (flags & PFIL_OUT) {
151 err = pfil_list_add(&ph->ph_out, func, arg, flags & ~PFIL_IN);
152 if (err) {
153 if (flags & PFIL_IN)
154 pfil_list_remove(&ph->ph_in, func, arg);
155 return err;
156 }
157 }
158 return 0;
159}
160
161static int
162pfil_list_add(pfil_list_t *list,
163 int (*func)(void *, struct mbuf **, struct ifnet *, int), void *arg,
164 int flags)
165{
166 struct packet_filter_hook *pfh;
167
168 /*
169 * First make sure the hook is not already there.
170 */
171 for (pfh = TAILQ_FIRST(list); pfh != NULL;
172 pfh = TAILQ_NEXT(pfh, pfil_link)) {
173 if (pfh->pfil_func == func &&
174 pfh->pfil_arg == arg)
175 return EEXIST;
176 }
177
178 pfh = (struct packet_filter_hook *)malloc(sizeof(*pfh), M_IFADDR,
179 (flags & PFIL_WAITOK) ? M_WAITOK : M_NOWAIT);
180 if (pfh == NULL)
181 return ENOMEM;
182
183 pfh->pfil_func = func;
184 pfh->pfil_arg = arg;
185
186 /*
187 * insert the input list in reverse order of the output list
188 * so that the same path is followed in or out of the kernel.
189 */
190 if (flags & PFIL_IN)
191 TAILQ_INSERT_HEAD(list, pfh, pfil_link);
192 else
193 TAILQ_INSERT_TAIL(list, pfh, pfil_link);
194
195 return 0;
196}
197
198/*
199 * pfil_remove_hook removes a specific function from the packet filter
200 * hook list.
201 */
202int
203pfil_remove_hook(int (*func)(void *, struct mbuf **, struct ifnet *, int),
204 void *arg, int flags, struct pfil_head *ph)
205{
206 int err = 0;
207
208 if (flags & PFIL_IN)
209 err = pfil_list_remove(&ph->ph_in, func, arg);
210 if ((err == 0) && (flags & PFIL_OUT))
211 err = pfil_list_remove(&ph->ph_out, func, arg);
212 return err;
213}
214
215/*
216 * pfil_list_remove is an internal function that takes a function off the
217 * specified list.
218 */
219static int
220pfil_list_remove(pfil_list_t *list,
221 int (*func)(void *, struct mbuf **, struct ifnet *, int), void *arg)
222{
223 struct packet_filter_hook *pfh;
224
225 for (pfh = TAILQ_FIRST(list); pfh != NULL;
226 pfh = TAILQ_NEXT(pfh, pfil_link)) {
227 if (pfh->pfil_func == func && pfh->pfil_arg == arg) {
228 TAILQ_REMOVE(list, pfh, pfil_link);
229 free(pfh, M_IFADDR);
230 return 0;
231 }
232 }
233 return ENOENT;
234}