npf_alg.c revision 1.3 
1/*	$NetBSD: npf_alg.c,v 1.3 2012/02/20 00:18:19 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 * XXX: locking
36 */
37
38#include <sys/cdefs.h>
39__KERNEL_RCSID(0, "$NetBSD: npf_alg.c,v 1.3 2012/02/20 00:18:19 rmind Exp $");
40
41#include <sys/param.h>
42#include <sys/kmem.h>
43#include <sys/pool.h>
44#include <net/pfil.h>
45
46#include "npf_impl.h"
47
48/* NAT ALG structure for registration. */
49struct npf_alg {
50	LIST_ENTRY(npf_alg)		na_entry;
51	npf_alg_t *			na_bptr;
52	npf_algfunc_t			na_match_func;
53	npf_algfunc_t			na_out_func;
54	npf_algfunc_t			na_in_func;
55	npf_algfunc_t			na_seid_func;
56};
57
58static LIST_HEAD(, npf_alg)		nat_alg_list	__read_mostly;
59
60void
61npf_alg_sysinit(void)
62{
63
64	LIST_INIT(&nat_alg_list);
65}
66
67void
68npf_alg_sysfini(void)
69{
70
71	KASSERT(LIST_EMPTY(&nat_alg_list));
72}
73
74/*
75 * npf_alg_register: register application-level gateway.
76 *
77 * XXX: Protected by module lock, but unify serialisation later.
78 */
79npf_alg_t *
80npf_alg_register(npf_algfunc_t match, npf_algfunc_t out, npf_algfunc_t in,
81    npf_algfunc_t seid)
82{
83	npf_alg_t *alg;
84
85	alg = kmem_zalloc(sizeof(npf_alg_t), KM_SLEEP);
86	alg->na_bptr = alg;
87	alg->na_match_func = match;
88	alg->na_out_func = out;
89	alg->na_in_func = in;
90	alg->na_seid_func = seid;
91	LIST_INSERT_HEAD(&nat_alg_list, alg, na_entry);
92	return alg;
93}
94
95/*
96 * npf_alg_unregister: unregister application-level gateway.
97 */
98int
99npf_alg_unregister(npf_alg_t *alg)
100{
101	npf_alg_t *it;
102
103	LIST_FOREACH(it, &nat_alg_list, na_entry) {
104		if (alg == it)
105			break;
106	}
107	if (it != NULL) {
108		LIST_REMOVE(alg, na_entry);
109	}
110	/* TODO: Flush relevant sessions. */
111	kmem_free(alg, sizeof(npf_alg_t));
112	return 0;
113}
114
115/*
116 * npf_alg_match: call ALG matching inspectors, determine if any ALG matches.
117 */
118bool
119npf_alg_match(npf_cache_t *npc, nbuf_t *nbuf, npf_nat_t *nt)
120{
121	npf_alg_t *alg;
122	npf_algfunc_t func;
123
124	LIST_FOREACH(alg, &nat_alg_list, na_entry) {
125		func = alg->na_match_func;
126		if (func && func(npc, nbuf, nt)) {
127			return true;
128		}
129	}
130	return false;
131}
132
133/*
134 * npf_alg_exec: execute ALG hooks for translation.
135 */
136void
137npf_alg_exec(npf_cache_t *npc, nbuf_t *nbuf, npf_nat_t *nt, const int di)
138{
139	npf_alg_t *alg;
140
141	LIST_FOREACH(alg, &nat_alg_list, na_entry) {
142		if ((di & PFIL_OUT) != 0 && alg->na_out_func != NULL) {
143			(alg->na_out_func)(npc, nbuf, nt);
144			continue;
145		}
146		if ((di & PFIL_IN) != 0 && alg->na_in_func != NULL) {
147			(alg->na_in_func)(npc, nbuf, nt);
148			continue;
149		}
150	}
151}
152
153bool
154npf_alg_sessionid(npf_cache_t *npc, nbuf_t *nbuf, npf_cache_t *key)
155{
156	npf_alg_t *alg;
157	npf_algfunc_t func;
158
159	LIST_FOREACH(alg, &nat_alg_list, na_entry) {
160		func = alg->na_seid_func;
161		if (func && func(npc, nbuf, (npf_nat_t *)key)) {
162			return true;
163		}
164	}
165	return false;
166}
167