uipc_accf.c revision 116182 
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
28#include <sys/cdefs.h>
29__FBSDID("$FreeBSD: head/sys/kern/uipc_accf.c 116182 2003-06-11 00:56:59Z obrien $");
30
31#define ACCEPT_FILTER_MOD
32
33#include "opt_param.h"
34#include <sys/param.h>
35#include <sys/systm.h>
36#include <sys/domain.h>
37#include <sys/kernel.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
46static SLIST_HEAD(, accept_filter) accept_filtlsthd =
47	SLIST_HEAD_INITIALIZER(&accept_filtlsthd);
48
49MALLOC_DEFINE(M_ACCF, "accf", "accept filter data");
50
51static int unloadable = 0;
52
53SYSCTL_DECL(_net_inet);	/* XXX: some header should do this for me */
54SYSCTL_NODE(_net_inet, OID_AUTO, accf, CTLFLAG_RW, 0, "Accept filters");
55SYSCTL_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 */
64int
65accept_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
85int
86accept_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
98struct accept_filter *
99accept_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
110int
111accept_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}
152