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 * $FreeBSD$
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/proc.h>
38 #include <sys/malloc.h>
39 #include <sys/mbuf.h>
40 #include <sys/protosw.h>
41 #include <sys/sysctl.h>
42 #include <sys/socket.h>
43 #include <sys/socketvar.h>
44 #include <sys/queue.h>
45
46 static SLIST_HEAD(, accept_filter) accept_filtlsthd =
47 SLIST_HEAD_INITIALIZER(&accept_filtlsthd);
48
49 MALLOC_DEFINE(M_ACCF, "accf", "accept filter data");
50
51 static int unloadable = 0;
52
53 SYSCTL_DECL(_net_inet); /* XXX: some header should do this for me */
54 SYSCTL_NODE(_net_inet, OID_AUTO, accf, CTLFLAG_RW, 0, "Accept filters");
55 SYSCTL_INT(_net_inet_accf, OID_AUTO, unloadable, CTLFLAG_RW, &unloadable, 0,
56 "Allow unload of accept filters (not recommended)");
57
58 /*
59 * must be passed a malloc'd structure so we don't explode if the kld
60 * is unloaded, we leak the struct on deallocation to deal with this,
61 * but if a filter is loaded with the same name as a leaked one we re-use
62 * the entry.
63 */
64 int
65 accept_filt_add(struct accept_filter *filt)
66 {
67 struct accept_filter *p;
68
69 SLIST_FOREACH(p, &accept_filtlsthd, accf_next)
70 if (strcmp(p->accf_name, filt->accf_name) == 0) {
71 if (p->accf_callback != NULL) {
72 return (EEXIST);
73 } else {
74 p->accf_callback = filt->accf_callback;
75 FREE(filt, M_ACCF);
76 return (0);
77 }
78 }
79
80 if (p == NULL)
81 SLIST_INSERT_HEAD(&accept_filtlsthd, filt, accf_next);
82 return (0);
83 }
84
85 int
86 accept_filt_del(char *name)
87 {
88 struct accept_filter *p;
89
90 p = accept_filt_get(name);
91 if (p == NULL)
92 return (ENOENT);
93
94 p->accf_callback = NULL;
95 return (0);
96 }
97
98 struct accept_filter *
99 accept_filt_get(char *name)
100 {
101 struct accept_filter *p;
102
103 SLIST_FOREACH(p, &accept_filtlsthd, accf_next)
104 if (strcmp(p->accf_name, name) == 0)
105 return (p);
106
107 return (NULL);
108 }
109
110 int
111 accept_filt_generic_mod_event(module_t mod, int event, void *data)
112 {
113 struct accept_filter *p;
114 struct accept_filter *accfp = (struct accept_filter *) data;
115 int s, error;
116
117 switch (event) {
118 case MOD_LOAD:
119 MALLOC(p, struct accept_filter *, sizeof(*p), M_ACCF, M_WAITOK);
120 bcopy(accfp, p, sizeof(*p));
121 s = splnet();
122 error = accept_filt_add(p);
123 splx(s);
124 break;
125
126 case MOD_UNLOAD:
127 /*
128 * Do not support unloading yet. we don't keep track of refcounts
129 * and unloading an accept filter callback and then having it called
130 * is a bad thing. A simple fix would be to track the refcount
131 * in the struct accept_filter.
132 */
133 if (unloadable != 0) {
134 s = splnet();
135 error = accept_filt_del(accfp->accf_name);
136 splx(s);
137 } else
138 error = EOPNOTSUPP;
139 break;
140
141 case MOD_SHUTDOWN:
142 error = 0;
143 break;
144
145 default:
146 error = EOPNOTSUPP;
147 break;
148 }
149
150 return (error);
151 }
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