uipc_accf.c revision 129876 
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 129876 2004-05-30 17:57:46Z phk $");
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/module.h>
41#include <sys/protosw.h>
42#include <sys/sysctl.h>
43#include <sys/socket.h>
44#include <sys/socketvar.h>
45#include <sys/queue.h>
46
47static SLIST_HEAD(, accept_filter) accept_filtlsthd =
48	SLIST_HEAD_INITIALIZER(&accept_filtlsthd);
49
50MALLOC_DEFINE(M_ACCF, "accf", "accept filter data");
51
52static int unloadable = 0;
53
54SYSCTL_DECL(_net_inet);	/* XXX: some header should do this for me */
55SYSCTL_NODE(_net_inet, OID_AUTO, accf, CTLFLAG_RW, 0, "Accept filters");
56SYSCTL_INT(_net_inet_accf, OID_AUTO, unloadable, CTLFLAG_RW, &unloadable, 0,
57	"Allow unload of accept filters (not recommended)");
58
59/*
60 * must be passed a malloc'd structure so we don't explode if the kld
61 * is unloaded, we leak the struct on deallocation to deal with this,
62 * but if a filter is loaded with the same name as a leaked one we re-use
63 * the entry.
64 */
65int
66accept_filt_add(struct accept_filter *filt)
67{
68	struct accept_filter *p;
69
70	SLIST_FOREACH(p, &accept_filtlsthd, accf_next)
71		if (strcmp(p->accf_name, filt->accf_name) == 0)  {
72			if (p->accf_callback != NULL) {
73				return (EEXIST);
74			} else {
75				p->accf_callback = filt->accf_callback;
76				FREE(filt, M_ACCF);
77				return (0);
78			}
79		}
80
81	if (p == NULL)
82		SLIST_INSERT_HEAD(&accept_filtlsthd, filt, accf_next);
83	return (0);
84}
85
86int
87accept_filt_del(char *name)
88{
89	struct accept_filter *p;
90
91	p = accept_filt_get(name);
92	if (p == NULL)
93		return (ENOENT);
94
95	p->accf_callback = NULL;
96	return (0);
97}
98
99struct accept_filter *
100accept_filt_get(char *name)
101{
102	struct accept_filter *p;
103
104	SLIST_FOREACH(p, &accept_filtlsthd, accf_next)
105		if (strcmp(p->accf_name, name) == 0)
106			return (p);
107
108	return (NULL);
109}
110
111int
112accept_filt_generic_mod_event(module_t mod, int event, void *data)
113{
114	struct accept_filter *p;
115	struct accept_filter *accfp = (struct accept_filter *) data;
116	int	s, error;
117
118	switch (event) {
119	case MOD_LOAD:
120		MALLOC(p, struct accept_filter *, sizeof(*p), M_ACCF, M_WAITOK);
121		bcopy(accfp, p, sizeof(*p));
122		s = splnet();
123		error = accept_filt_add(p);
124		splx(s);
125		break;
126
127	case MOD_UNLOAD:
128		/*
129		 * Do not support unloading yet. we don't keep track of refcounts
130		 * and unloading an accept filter callback and then having it called
131		 * is a bad thing.  A simple fix would be to track the refcount
132		 * in the struct accept_filter.
133		 */
134		if (unloadable != 0) {
135			s = splnet();
136			error = accept_filt_del(accfp->accf_name);
137			splx(s);
138		} else
139			error = EOPNOTSUPP;
140		break;
141
142	case MOD_SHUTDOWN:
143		error = 0;
144		break;
145
146	default:
147		error = EOPNOTSUPP;
148		break;
149	}
150
151	return (error);
152}
153