pfil_hook_get() is only used in pfil.c, so hide it
[dragonfly.git] / sys / net / pfil.c
CommitLineData
9e99d0a2 1/* $NetBSD: pfil.c,v 1.20 2001/11/12 23:49:46 lukem Exp $ */
03b72fbe 2/* $DragonFly: src/sys/net/pfil.c,v 1.6 2008/09/14 02:05:07 sephe Exp $ */
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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
afabe90c 44static int pfil_list_add(struct pfil_head *,
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45 int (*)(void *, struct mbuf **, struct ifnet *, int), void *, int);
46
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47static int pfil_list_remove(struct pfil_head *,
48 int (*)(void *, struct mbuf **, struct ifnet *, int), void *, int);
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49
50LIST_HEAD(, pfil_head) pfil_head_list =
51 LIST_HEAD_INITIALIZER(&pfil_head_list);
52
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53static __inline struct packet_filter_hook *
54pfil_hook_get(int dir, struct pfil_head *ph)
55{
56
57 if (dir == PFIL_IN)
58 return (TAILQ_FIRST(&ph->ph_in));
59 else if (dir == PFIL_OUT)
60 return (TAILQ_FIRST(&ph->ph_out));
61 else
62 return (NULL);
63}
64
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65/*
66 * pfil_run_hooks() runs the specified packet filter hooks.
67 */
68int
69pfil_run_hooks(struct pfil_head *ph, struct mbuf **mp, struct ifnet *ifp,
70 int dir)
71{
72 struct packet_filter_hook *pfh;
73 struct mbuf *m = *mp;
74 int rv = 0;
75
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);
80 if (rv != 0 || m == NULL)
81 break;
82 }
83 }
84
85 *mp = m;
86 return (rv);
87}
88
89/*
90 * pfil_head_register() registers a pfil_head with the packet filter
91 * hook mechanism.
92 */
93int
94pfil_head_register(struct pfil_head *ph)
95{
96 struct pfil_head *lph;
97
98 for (lph = LIST_FIRST(&pfil_head_list); lph != NULL;
99 lph = LIST_NEXT(lph, ph_list)) {
100 if (ph->ph_type == lph->ph_type &&
101 ph->ph_un.phu_val == lph->ph_un.phu_val)
102 return EEXIST;
103 }
104
105 TAILQ_INIT(&ph->ph_in);
106 TAILQ_INIT(&ph->ph_out);
afabe90c 107 ph->ph_hashooks = 0;
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108
109 LIST_INSERT_HEAD(&pfil_head_list, ph, ph_list);
110
111 return (0);
112}
113
114/*
115 * pfil_head_unregister() removes a pfil_head from the packet filter
116 * hook mechanism.
117 */
118int
119pfil_head_unregister(struct pfil_head *pfh)
120{
121
122 LIST_REMOVE(pfh, ph_list);
123 return (0);
124}
125
126/*
127 * pfil_head_get() returns the pfil_head for a given key/dlt.
128 */
129struct pfil_head *
130pfil_head_get(int type, u_long val)
131{
132 struct pfil_head *ph;
133
134 for (ph = LIST_FIRST(&pfil_head_list); ph != NULL;
135 ph = LIST_NEXT(ph, ph_list)) {
136 if (ph->ph_type == type &&
137 ph->ph_un.phu_val == val)
138 break;
139 }
140
141 return (ph);
142}
143
144/*
145 * pfil_add_hook() adds a function to the packet filter hook. the
146 * flags are:
147 * PFIL_IN call me on incoming packets
148 * PFIL_OUT call me on outgoing packets
149 * PFIL_ALL call me on all of the above
702cc4db 150 * PFIL_WAITOK OK to call kmalloc with M_WAITOK.
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151 */
152int
153pfil_add_hook(int (*func)(void *, struct mbuf **, struct ifnet *, int),
154 void *arg, int flags, struct pfil_head *ph)
155{
156 int err = 0;
157
158 if (flags & PFIL_IN) {
afabe90c 159 err = pfil_list_add(ph, func, arg, flags & ~PFIL_OUT);
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160 if (err)
161 return err;
162 }
163 if (flags & PFIL_OUT) {
afabe90c 164 err = pfil_list_add(ph, func, arg, flags & ~PFIL_IN);
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165 if (err) {
166 if (flags & PFIL_IN)
afabe90c 167 pfil_list_remove(ph, func, arg, PFIL_IN);
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168 return err;
169 }
170 }
171 return 0;
172}
173
174static int
afabe90c 175pfil_list_add(struct pfil_head *ph,
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176 int (*func)(void *, struct mbuf **, struct ifnet *, int), void *arg,
177 int flags)
178{
179 struct packet_filter_hook *pfh;
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180 pfil_list_t *list;
181
182 list = (flags & PFIL_IN) ? &ph->ph_in : &ph->ph_out;
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183
184 /*
185 * First make sure the hook is not already there.
186 */
187 for (pfh = TAILQ_FIRST(list); pfh != NULL;
188 pfh = TAILQ_NEXT(pfh, pfil_link)) {
189 if (pfh->pfil_func == func &&
190 pfh->pfil_arg == arg)
191 return EEXIST;
192 }
193
efda3bd0 194 pfh = (struct packet_filter_hook *)kmalloc(sizeof(*pfh), M_IFADDR,
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195 (flags & PFIL_WAITOK) ? M_WAITOK : M_NOWAIT);
196 if (pfh == NULL)
197 return ENOMEM;
198
199 pfh->pfil_func = func;
200 pfh->pfil_arg = arg;
201
202 /*
203 * insert the input list in reverse order of the output list
204 * so that the same path is followed in or out of the kernel.
205 */
206 if (flags & PFIL_IN)
207 TAILQ_INSERT_HEAD(list, pfh, pfil_link);
208 else
209 TAILQ_INSERT_TAIL(list, pfh, pfil_link);
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210 ph->ph_hashooks = 1;
211 return (0);
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212}
213
214/*
215 * pfil_remove_hook removes a specific function from the packet filter
216 * hook list.
217 */
218int
219pfil_remove_hook(int (*func)(void *, struct mbuf **, struct ifnet *, int),
220 void *arg, int flags, struct pfil_head *ph)
221{
222 int err = 0;
223
224 if (flags & PFIL_IN)
afabe90c 225 err = pfil_list_remove(ph, func, arg, PFIL_IN);
9e99d0a2 226 if ((err == 0) && (flags & PFIL_OUT))
afabe90c 227 err = pfil_list_remove(ph, func, arg, PFIL_OUT);
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228 return err;
229}
230
231/*
232 * pfil_list_remove is an internal function that takes a function off the
afabe90c 233 * specified list. Clear ph_hashooks if no functions remain on any list.
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234 */
235static int
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236pfil_list_remove(struct pfil_head *ph,
237 int (*func)(void *, struct mbuf **, struct ifnet *, int), void *arg,
238 int flags)
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239{
240 struct packet_filter_hook *pfh;
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241 pfil_list_t *list;
242
243 list = (flags & PFIL_IN) ? &ph->ph_in : &ph->ph_out;
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244
245 for (pfh = TAILQ_FIRST(list); pfh != NULL;
246 pfh = TAILQ_NEXT(pfh, pfil_link)) {
247 if (pfh->pfil_func == func && pfh->pfil_arg == arg) {
248 TAILQ_REMOVE(list, pfh, pfil_link);
efda3bd0 249 kfree(pfh, M_IFADDR);
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250 if (TAILQ_EMPTY(&ph->ph_in) && TAILQ_EMPTY(&ph->ph_out))
251 ph->ph_hashooks = 0;
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252 return 0;
253 }
254 }
255 return ENOENT;
256}