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npf_alg.c revision 1.2.16.4 
      1 /*	$NetBSD: npf_alg.c,v 1.2.16.4 2013/02/08 19:18:11 riz 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 1.2.16.4 2013/02/08 19:18:11 riz 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. */
     50 struct 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 
     58 static LIST_HEAD(, npf_alg)	nat_alg_list	__cacheline_aligned;
     59 static kmutex_t			nat_alg_lock	__cacheline_aligned;
     60 static pserialize_t		nat_alg_psz	__cacheline_aligned;
     61 
     62 void
     63 npf_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 
     71 void
     72 npf_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  */
     85 npf_alg_t *
     86 npf_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  */
    107 int
    108 npf_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  */
    127 bool
    128 npf_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  */
    150 void
    151 npf_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 
    167 npf_session_t *
    168 npf_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