uipc_accf.c revision 77598 
1129864Sstefanf/*
2129864Sstefanf * Copyright (c) 2000 Paycounter, Inc.
3129864Sstefanf * Author: Alfred Perlstein <alfred@paycounter.com>, <alfred@FreeBSD.org>
4129864Sstefanf * All rights reserved.
5129864Sstefanf *
6129864Sstefanf * Redistribution and use in source and binary forms, with or without
7129864Sstefanf * modification, are permitted provided that the following conditions
8129864Sstefanf * are met:
9129864Sstefanf * 1. Redistributions of source code must retain the above copyright
10129864Sstefanf *    notice, this list of conditions and the following disclaimer.
11129864Sstefanf * 2. Redistributions in binary form must reproduce the above copyright
12129864Sstefanf *    notice, this list of conditions and the following disclaimer in the
13129864Sstefanf *    documentation and/or other materials provided with the distribution.
14129864Sstefanf *
15129864Sstefanf * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16129864Sstefanf * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17129864Sstefanf * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18129864Sstefanf * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19129864Sstefanf * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20129864Sstefanf * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21129864Sstefanf * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22129864Sstefanf * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23129864Sstefanf * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24129864Sstefanf * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25129864Sstefanf * SUCH DAMAGE.
26129864Sstefanf *
27129864Sstefanf *	$FreeBSD: head/sys/kern/uipc_accf.c 77598 2001-06-01 21:47:34Z jesper $
28129864Sstefanf */
29129864Sstefanf
30189803Sdas#define ACCEPT_FILTER_MOD
31129864Sstefanf
32129864Sstefanf#include "opt_param.h"
33129864Sstefanf#include <sys/param.h>
34129864Sstefanf#include <sys/systm.h>
35189803Sdas#include <sys/domain.h>
36181374Sdas#include <sys/kernel.h>
37189803Sdas#include <sys/malloc.h>
38129864Sstefanf#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
45static SLIST_HEAD(, accept_filter) accept_filtlsthd =
46	SLIST_HEAD_INITIALIZER(&accept_filtlsthd);
47
48MALLOC_DEFINE(M_ACCF, "accf", "accept filter data");
49
50static int unloadable = 0;
51
52SYSCTL_DECL(_net_inet);	/* XXX: some header should do this for me */
53SYSCTL_NODE(_net_inet, OID_AUTO, accf, CTLFLAG_RW, 0, "Accept filters");
54SYSCTL_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 */
63int
64accept_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
84int
85accept_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
97struct accept_filter *
98accept_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
109int
110accept_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}
151