npf_alg.c revision 1.6 
1/*	$NetBSD: npf_alg.c,v 1.6 2012/12/24 19:05:42 rmind Exp $	*/
2
3/*-
4 * Copyright (c) 2010 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This material is based upon work partially supported by The
8 * NetBSD Foundation under a contract with Mindaugas Rasiukevicius.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 *    notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 *    notice, this list of conditions and the following disclaimer in the
17 *    documentation and/or other materials provided with the distribution.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 * POSSIBILITY OF SUCH DAMAGE.
30 */
31
32/*
33 * NPF interface for application level gateways (ALGs).
34 */
35
36#include <sys/cdefs.h>
37__KERNEL_RCSID(0, "$NetBSD: npf_alg.c,v 1.6 2012/12/24 19:05:42 rmind Exp $");
38
39#include <sys/param.h>
40#include <sys/types.h>
41
42#include <sys/kmem.h>
43#include <sys/pserialize.h>
44#include <sys/mutex.h>
45#include <net/pfil.h>
46
47#include "npf_impl.h"
48
49/* NAT ALG structure for registration. */
50struct npf_alg {
51	LIST_ENTRY(npf_alg)	na_entry;
52	npf_alg_t *		na_bptr;
53	npf_alg_func_t		na_match_func;
54	npf_alg_func_t		na_tr_func;
55	npf_alg_sfunc_t		na_se_func;
56};
57
58static LIST_HEAD(, npf_alg)	nat_alg_list	__cacheline_aligned;
59static kmutex_t			nat_alg_lock	__cacheline_aligned;
60static pserialize_t		nat_alg_psz	__cacheline_aligned;
61
62void
63npf_alg_sysinit(void)
64{
65
66	mutex_init(&nat_alg_lock, MUTEX_DEFAULT, IPL_NONE);
67	nat_alg_psz = pserialize_create();
68	LIST_INIT(&nat_alg_list);
69}
70
71void
72npf_alg_sysfini(void)
73{
74
75	KASSERT(LIST_EMPTY(&nat_alg_list));
76	pserialize_destroy(nat_alg_psz);
77	mutex_destroy(&nat_alg_lock);
78}
79
80/*
81 * npf_alg_register: register application-level gateway.
82 *
83 * XXX: Protected by module lock, but unify serialisation later.
84 */
85npf_alg_t *
86npf_alg_register(npf_alg_func_t mfunc, npf_alg_func_t tfunc,
87    npf_alg_sfunc_t sfunc)
88{
89	npf_alg_t *alg;
90
91	alg = kmem_zalloc(sizeof(npf_alg_t), KM_SLEEP);
92	alg->na_bptr = alg;
93	alg->na_match_func = mfunc;
94	alg->na_tr_func = tfunc;
95	alg->na_se_func = sfunc;
96
97	mutex_enter(&nat_alg_lock);
98	LIST_INSERT_HEAD(&nat_alg_list, alg, na_entry);
99	mutex_exit(&nat_alg_lock);
100
101	return alg;
102}
103
104/*
105 * npf_alg_unregister: unregister application-level gateway.
106 */
107int
108npf_alg_unregister(npf_alg_t *alg)
109{
110
111	mutex_enter(&nat_alg_lock);
112	LIST_REMOVE(alg, na_entry);
113	pserialize_perform(nat_alg_psz);
114	mutex_exit(&nat_alg_lock);
115
116	npf_core_enter();
117	npf_ruleset_freealg(npf_core_natset(), alg);
118	npf_core_exit();
119
120	kmem_free(alg, sizeof(npf_alg_t));
121	return 0;
122}
123
124/*
125 * npf_alg_match: call ALG matching inspectors, determine if any ALG matches.
126 */
127bool
128npf_alg_match(npf_cache_t *npc, nbuf_t *nbuf, npf_nat_t *nt, int di)
129{
130	npf_alg_t *alg;
131	bool match = false;
132	int s;
133
134	s = pserialize_read_enter();
135	LIST_FOREACH(alg, &nat_alg_list, na_entry) {
136		npf_alg_func_t func = alg->na_match_func;
137
138		if (func && func(npc, nbuf, nt, di)) {
139			match = true;
140			break;
141		}
142	}
143	pserialize_read_exit(s);
144	return match;
145}
146
147/*
148 * npf_alg_exec: execute ALG hooks for translation.
149 */
150void
151npf_alg_exec(npf_cache_t *npc, nbuf_t *nbuf, npf_nat_t *nt, int di)
152{
153	npf_alg_t *alg;
154	int s;
155
156	s = pserialize_read_enter();
157	LIST_FOREACH(alg, &nat_alg_list, na_entry) {
158		npf_alg_func_t func;
159
160		if ((func = alg->na_tr_func) != NULL) {
161			(func)(npc, nbuf, nt, di);
162		}
163	}
164	pserialize_read_exit(s);
165}
166
167npf_session_t *
168npf_alg_session(npf_cache_t *npc, nbuf_t *nbuf, int di)
169{
170	npf_session_t *se = NULL;
171	npf_alg_t *alg;
172	int s;
173
174	s = pserialize_read_enter();
175	LIST_FOREACH(alg, &nat_alg_list, na_entry) {
176		npf_alg_sfunc_t func = alg->na_se_func;
177
178		if (func && (se = func(npc, nbuf, di)) != NULL) {
179			break;
180		}
181	}
182	pserialize_read_exit(s);
183	return se;
184}
185