npf_alg.c revision 1.1 
1/*	$NetBSD: npf_alg.c,v 1.1 2010/08/22 18:56:22 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#ifdef _KERNEL
37#include <sys/cdefs.h>
38__KERNEL_RCSID(0, "$NetBSD: npf_alg.c,v 1.1 2010/08/22 18:56:22 rmind Exp $");
39
40#include <sys/param.h>
41#include <sys/kernel.h>
42#endif
43
44#include <sys/kmem.h>
45#include <sys/pool.h>
46#include <net/pfil.h>
47
48#include "npf_impl.h"
49
50/* NAT ALG structure for registration. */
51struct npf_alg {
52	LIST_ENTRY(npf_alg)		na_entry;
53	void *				na_ptr;
54	npf_algfunc_t			na_match_func;
55	npf_algfunc_t			na_out_func;
56	npf_algfunc_t			na_in_func;
57	npf_algfunc_t			na_seid_func;
58};
59
60static LIST_HEAD(, npf_alg)		nat_alg_list;
61
62void
63npf_alg_sysinit(void)
64{
65
66	LIST_INIT(&nat_alg_list);
67}
68
69void
70npf_alg_sysfini(void)
71{
72
73	KASSERT(LIST_EMPTY(&nat_alg_list));
74}
75
76/*
77 * npf_alg_register: register application-level gateway.
78 *
79 * XXX: Protected by module lock, but unify serialisation later.
80 */
81npf_alg_t *
82npf_alg_register(npf_algfunc_t match, npf_algfunc_t out, npf_algfunc_t in,
83    npf_algfunc_t seid)
84{
85	npf_alg_t *alg;
86
87	alg = kmem_alloc(sizeof(npf_alg_t), KM_SLEEP);
88	alg->na_ptr = alg;
89	alg->na_match_func = match;
90	alg->na_out_func = out;
91	alg->na_in_func = in;
92	alg->na_seid_func = seid;
93	LIST_INSERT_HEAD(&nat_alg_list, alg, na_entry);
94	return alg;
95}
96
97/*
98 * npf_alg_unregister: unregister application-level gateway.
99 */
100int
101npf_alg_unregister(npf_alg_t *alg)
102{
103	npf_alg_t *it;
104
105	LIST_FOREACH(it, &nat_alg_list, na_entry) {
106		if (alg == it)
107			break;
108	}
109	if (it != NULL) {
110		LIST_REMOVE(alg, na_entry);
111	}
112	/* TODO: Flush relevant sessions. */
113	kmem_free(alg, sizeof(npf_alg_t));
114	return 0;
115}
116
117void
118npf_alg_match(npf_cache_t *npc, nbuf_t *nbuf, npf_nat_t *nt)
119{
120	npf_alg_t *alg;
121	npf_algfunc_t func;
122
123	LIST_FOREACH(alg, &nat_alg_list, na_entry) {
124		func = alg->na_match_func;
125		if (__predict_true(func != NULL)) {
126			func(npc, nbuf, nt);
127			return;
128		}
129	}
130}
131
132/*
133 * npf_alg_exec: execute in/out inspection hooks of each ALG.
134 */
135void
136npf_alg_exec(npf_cache_t *npc, nbuf_t *nbuf, npf_nat_t *nt, const int di)
137{
138	npf_alg_t *alg;
139
140	LIST_FOREACH(alg, &nat_alg_list, na_entry) {
141		if ((di & PFIL_OUT) != 0 && alg->na_out_func != NULL) {
142			(alg->na_out_func)(npc, nbuf, nt);
143			continue;
144		}
145		if ((di & PFIL_IN) != 0 && alg->na_in_func != NULL) {
146			(alg->na_in_func)(npc, nbuf, nt);
147			continue;
148		}
149	}
150}
151
152bool
153npf_alg_sessionid(npf_cache_t *npc, nbuf_t *nbuf, npf_cache_t *key)
154{
155	npf_alg_t *alg;
156	npf_algfunc_t func;
157
158	LIST_FOREACH(alg, &nat_alg_list, na_entry) {
159		func = alg->na_seid_func;
160		if (__predict_true(func == NULL)) {
161			continue;
162		}
163		if (func(npc, nbuf, key)) {
164			return true;
165		}
166	}
167	return false;
168}
169