FreeBSD/Linux Kernel Cross Reference
sys/kern/uipc_accf.c
1 /*
2 * Copyright (c) 2000 Paycounter, Inc.
3 * Author: Alfred Perlstein <alfred@paycounter.com>, <alfred@FreeBSD.org>
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
26 *
27 * $FreeBSD: releng/5.0/sys/kern/uipc_accf.c 77598 2001-06-01 21:47:34Z jesper $
28 */
29
30 #define ACCEPT_FILTER_MOD
31
32 #include "opt_param.h"
33 #include <sys/param.h>
34 #include <sys/systm.h>
35 #include <sys/domain.h>
36 #include <sys/kernel.h>
37 #include <sys/malloc.h>
38 #include <sys/mbuf.h>
39 #include <sys/protosw.h>
40 #include <sys/sysctl.h>
41 #include <sys/socket.h>
42 #include <sys/socketvar.h>
43 #include <sys/queue.h>
44
45 static SLIST_HEAD(, accept_filter) accept_filtlsthd =
46 SLIST_HEAD_INITIALIZER(&accept_filtlsthd);
47
48 MALLOC_DEFINE(M_ACCF, "accf", "accept filter data");
49
50 static int unloadable = 0;
51
52 SYSCTL_DECL(_net_inet); /* XXX: some header should do this for me */
53 SYSCTL_NODE(_net_inet, OID_AUTO, accf, CTLFLAG_RW, 0, "Accept filters");
54 SYSCTL_INT(_net_inet_accf, OID_AUTO, unloadable, CTLFLAG_RW, &unloadable, 0,
55 "Allow unload of accept filters (not recommended)");
56
57 /*
58 * must be passed a malloc'd structure so we don't explode if the kld
59 * is unloaded, we leak the struct on deallocation to deal with this,
60 * but if a filter is loaded with the same name as a leaked one we re-use
61 * the entry.
62 */
63 int
64 accept_filt_add(struct accept_filter *filt)
65 {
66 struct accept_filter *p;
67
68 SLIST_FOREACH(p, &accept_filtlsthd, accf_next)
69 if (strcmp(p->accf_name, filt->accf_name) == 0) {
70 if (p->accf_callback != NULL) {
71 return (EEXIST);
72 } else {
73 p->accf_callback = filt->accf_callback;
74 FREE(filt, M_ACCF);
75 return (0);
76 }
77 }
78
79 if (p == NULL)
80 SLIST_INSERT_HEAD(&accept_filtlsthd, filt, accf_next);
81 return (0);
82 }
83
84 int
85 accept_filt_del(char *name)
86 {
87 struct accept_filter *p;
88
89 p = accept_filt_get(name);
90 if (p == NULL)
91 return (ENOENT);
92
93 p->accf_callback = NULL;
94 return (0);
95 }
96
97 struct accept_filter *
98 accept_filt_get(char *name)
99 {
100 struct accept_filter *p;
101
102 SLIST_FOREACH(p, &accept_filtlsthd, accf_next)
103 if (strcmp(p->accf_name, name) == 0)
104 return (p);
105
106 return (NULL);
107 }
108
109 int
110 accept_filt_generic_mod_event(module_t mod, int event, void *data)
111 {
112 struct accept_filter *p;
113 struct accept_filter *accfp = (struct accept_filter *) data;
114 int s, error;
115
116 switch (event) {
117 case MOD_LOAD:
118 MALLOC(p, struct accept_filter *, sizeof(*p), M_ACCF, M_WAITOK);
119 bcopy(accfp, p, sizeof(*p));
120 s = splnet();
121 error = accept_filt_add(p);
122 splx(s);
123 break;
124
125 case MOD_UNLOAD:
126 /*
127 * Do not support unloading yet. we don't keep track of refcounts
128 * and unloading an accept filter callback and then having it called
129 * is a bad thing. A simple fix would be to track the refcount
130 * in the struct accept_filter.
131 */
132 if (unloadable != 0) {
133 s = splnet();
134 error = accept_filt_del(accfp->accf_name);
135 splx(s);
136 } else
137 error = EOPNOTSUPP;
138 break;
139
140 case MOD_SHUTDOWN:
141 error = 0;
142 break;
143
144 default:
145 error = EOPNOTSUPP;
146 break;
147 }
148
149 return (error);
150 }
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